9H-fluorene

9H-fluorene (flor′en)

Parent compound of 2-acetylaminofluorene; occurs in coal tar.

H
H

Abbreviation or symbol for hydrogen; hyperopia; hyperopic; horizontal; Hauch; Holzknecht unit; henry, unit of electrical inductance; the Fraunhofer line at λ 3968 due to calcium; histidine; magnetic field strength; heroin; histone; histamine.

H+
H⁺

Symbol for hydrogen ion, the proton.

1H
¹H

Symbol for hydrogen-1.

2H
²H

Symbol for hydrogen-2.

3H
³H

Symbol for hydrogen-3.

H
H

Symbol for enthalpy, heat content, in the equation for free energy; fluence; magnetic field strength.

h
h

Symbol for hecto-; height; hour.

hν
hν

Symbol for photon, and represents photon energy, where h = Planck's constant and ν = frequency of electromagnetic wave.

h
h

Symbol for Planck constant; h = h/2π.

HAA
HAA

Abbreviation for hepatitis-associated antigen.

Haab
Haab

Otto, Swiss ophthalmologist, 1850–1931.

Haase rule
Haase rule

See under rule.

habena
habena, pl .habenae (ha-be′na, -be′ne)

1. A frenum or restricting fibrous band. 2. A restraining bandage. 3. SYN: habenula (2) . [L. strap]

habenal
habenal, habenar (hab′e-nal, ha-be′nar)

Relating to a habena.

habenula
habenula, pl .habenulae (ha-ben′u-la, -le) [TA]

1. SYN: frenulum. 2. [TA] In neuroanatomy, the term originally denoted the stalk of the pineal gland (pineal h.; pedunculus of pineal body), but gradually came to refer to a neighboring group of nerve cells with which the pineal gland was believed to be associated, the habenular nucleus. Currently, the TA term refers exclusively to this circumscript cell mass in the caudal and dorsal aspect of the dorsal thalamus, embedded in the posterior end of the medullary stria from which it receives most of its afferent fibers. By way of the retroflex fasciculus (habenulointerpeduncular tract) it projects to the interpeduncular nucleus and other paramedian cell groups of the midbrain tegmentum. Despite its proximity to the pineal stalk, no habenulopineal fiber connection is known to exist. It is a part of the epithalamus. SYN: habena (3) . [L.]
h. of cecum extension of the mesocolic tenia, dorsal or ventral to the terminal ileum.
Haller h. rarely used term for the cordlike remains of the vaginal process of the peritoneum. SYN: Scarpa h..
habenulae perforatae SYN: foramina nervosa, under foramen.
pineal h. the peduncle or stalk of the pineal gland. See h. (2) .
Scarpa h. SYN: Haller h..
h. urethralis one of two fine, whitish lines running from the meatus urethrae to the clitoris in girls and young women; the vestiges of the anterior part of the corpus spongiosum.

habenular
habenular (ha-ben′u-lar)

Relating to a habenula, especially the stalk of the pineal body.

Haber
Haber

Henry, British dermatologist, 1900–1962. See H. syndrome.

Habermann
Habermann

R., German dermatologist, 1884–1941. See Mucha-H. disease.

habit
habit

1. An act, behavioral response, practice, or custom established in one's repertoire by frequent repetition of the same act. SEE ALSO: addiction. 2. A basic variable in the study of conditioning and learning used to designate a new response learned either by association or by being followed by a reward or reinforced event. See conditioning, learning. [L. habeo, pp. habitus, to have]

habituation
habituation (ha-bit-choo-a′shun)

1. The process of forming a habit, referring generally to psychological dependence on the continued use of a drug to maintain a sense of well-being, which can result in drug addiction. 2. The method by which the nervous system reduces or inhibits responsiveness during repeated stimulation.

habitus
habitus (hab′i-tus)

The physical characteristics of a person. [L. habit]
fetal h. relationship of one fetal part to another. SYN: fetal attitude.
gracile h. small stature, frail, underweight appearance.

Habronema
Habronema (ha-bro-ne′ma)

A genus of spiruroid nematodes inhabiting the stomach of horses. The larvae develop in housefly and stable fly maggots living in manure, become infective when the fly larvae pupate, and are carried by adult flies to open wounds on horses, where they are left and cause cutaneous habronemiasis; reinfection of the horse's stomach by H. occurs by accidental ingestion of infected flies or from licking wounds in which infective larvae are found. [G. habros, graceful, delicate, + nema, a thread]
H. majus one of two species (the other being H. microstoma) similar in appearance, hosts, distribution, and life cycle to H. muscae; the intermediate host is the stable fly, Stomoxys calcitrans.
H. megastoma a species that causes tumors in gastric mucosa containing large numbers of the small nematodes; the larvae cause cutaneous habronemiasis; the intermediate host is the common housefly, Musca domestica.
H. microstoma H. majus.
H. muscae a species that occurs in the stomach of the horse, mule, ass, or zebra; the intermediate host is the common housefly, Musca domestica, or related flies.

hacking
hacking (hak′ing)

A chopping stroke made with the edge of the hand in massage.

Hadfield
Hadfield

Geoffrey, British physician, 1889–1968. See Clarke-H. syndrome.

Hadrurus
Hadrurus (ha-droo′rus)

A genus of scorpions found in the southwestern U.S., characterized by numerous setae on the stinger; the commonest species is H. arizonensis, the olive hairy scorpion. SEE ALSO: Scorpionida. [G. hadros, thick, stout, + ouro, tail]

Haeckel
Haeckel

Ernst H.P.A., German naturalist, 1834–1919. See H. gastrea theory, H. law.

haem- haem-

See hem-.

Haemadipsa ceylonica
Haemadipsa ceylonica (he-ma-dip′sa sa-lon′i-ka)

A species of land leech found in Sri Lanka; it attaches itself to the skin of animals or humans. Its bite is painful, and numerous bites may cause anemia. [G. haima, blood, + dipsa, thirst]

Haemamoeba
Haemamoeba (he-ma-me′ba)

Old term for ameboid protozoa now classified in the suborder Haemosporina, blood parasites that include the genus Plasmodium. [G. haima, blood, + amoibe, change]

Haemaphysalis
Haemaphysalis (he-ma-fi′sa-lis)

A genus of small, eyeless, inornate ticks. As larvae and nymphs, they are found chiefly on small mammals and birds; as adults, they are found on larger mammals and some birds. They are important as vectors of protozoa and viruses, (e.g., Kyasanur Forest disease virus). [G. haima, blood, + physaleos, full of wind]
H. cinnabarina a tick that occurs chiefly in the dry district of British Columbia; this species can cause tick paralysis in both humans and animals. [G. kinnabarinos, like cinnabar, vermilion]
H. concinna common rodent tick species of the area formerly known as the U.S.S.R. that is a vector and reservoir of tick typhus.
H. leachi a species of Africa, Asia, and Australia that occurs on domestic and wild carnivores, on small rodents, and occasionally on cattle; it transmits canine babesiosis and boutonneuse fever.
H. spinigera a tropical forest species in India that is a vector of Kyasanur Forest disease; various rodents and insectivores serve as hosts of immature ticks of this species, which carry an arbovirus of the Russian spring-summer B group complex; monkeys act as reservoirs of human infection.

Haematopinus
Haematopinus (he′ma-to-pi′nus)

An important genus of sucking lice (family Haematopinidae) affecting swine and other domestic and wild animals; it is normally nonpathogenic. H. asini affects horses, mules, and asses; H. eurysternus and H. quadripertusus, cattle; and H. suis, swine. [G. haima, blood, + L. pinus, pine tree]

Haemococcidium
Haemococcidium (he′mo-kok-sid′e-um)

Old name for Plasmodium species. [G. haima, blood, + kokkos, berry]

Haemodipsus ventricosus
Haemodipsus ventricosus (he-mo-dip′sus ven-tri-ko′sus)

The rabbit louse, a transmitter of Francisella tularensis. [G. haima, blood, + dipsos, thirst; L. venter (ventr-), belly]

Haemogregarina
Haemogregarina (he′mo-greg-a-ri′na)

A sporozoan coccidian genus (order Eucoccidiida, family Haemogregarinidae) that parasitizes the blood cells of cold-blooded animals and the digestive system of invertebrate primary hosts in an obligatory two-host cycle. [G. haima, blood, + L. grex, a flock]

Haemonchus
Haemonchus (he-mong′kus)

An economically important genus of nematode parasites (family Trichostrongylidae) occurring in the abomasum of ruminant animals and causing severe anemia, especially in younger or previously unexposed animals. Some significant species are Haemonchus placei (in cattle, sheep, and goats), Haemonchus similis (in cattle and sheep), and Haemonchus contortus, the stomach, barberpole, or twisted wire worm of cattle, sheep, goats, and other ruminants, of which a few cases have been reported from humans; accidental parasite of humans. [G. haima, blood, + onchos, spear]

Haemophilus
Haemophilus (he-mof′i-lus)

A genus of aerobic to facultatively anaerobic, nonmotile bacteria (family Brucellaceae) containing minute, Gram-negative, rod-shaped cells that sometimes form threads and are pleomorphic. These organisms are strictly parasitic, growing best, or only, on media containing blood. They may or may not be pathogenic. They occur in various lesions and secretions, as well as in normal respiratory tracts, of vertebrates. The type species is H. influenzae. [G. haima, blood, + philos, fond]
H. actinomycetemcomitans SYN: Actinobacillus actinomycetemcomitans.
H. aegyptius a bacterial species that causes acute or subacute infectious conjunctivitis in warm climates. SYN: Koch-Weeks bacillus.
H. aphrophilus a bacterial species found in the blood and, rarely, on the heart valve as a cause of endocarditis.
H. ducreyi a bacterial species that causes the sexually transmitted soft chancre (chancroid). SYN: Ducrey bacillus.
H. haemolyticus a bacterial species that is usually nonpathogenic but which, on rare occasions, causes subacute endocarditis.
H. influenzae a bacterial species found in the respiratory tract that causes acute respiratory infections, including pneumonia, acute conjunctivitis, otitis, and purulent meningitis in children (rarely in adults in whom it contributes to sinusitis and chronic bronchitis). Originally considered to be the cause of influenza, it is the type species of the genus H.. SYN: influenza bacillus, Weeks bacillus.
H. influenzae Type b the most virulent serotype (there are six, a–f, based on antigenic typing of the polysaccharide capsule); species responsible for meningitis and respiratory infections in young children.
nontypeable H. influenzae bacterial species that is a major pathogen in acute otitis media.
H. parahaemolyticus a bacterial species found in the upper respiratory tract and associated frequently with pharyngitis; occasionally causes subacute endocarditis.
H. parainfluenzae a bacterial species that is usually nonpathogenic but which occasionally causes subacute endocarditis.
H. paratropicalis a relatively nonpathogenic bacterial species that has been associated with human infection, including cases of endocarditis.
H. segnis a usually saprophytic bacterial species that occasionally causes endocarditis, meningitis, and other infections in humans.

Haemoproteus
Haemoproteus (he′mo-pro′te-us)

A genus of sporozoa (suborder Haemosporina) parasitic in birds and reptiles, combined with Leucocytozoon, Hepatocystis, and other genera in the family Haemoproteidae. Schizogony occurs in endothelial cells of blood vessels, especially in the lungs of the host, while halter-shaped gametocytes are found in the red blood cells. Infection is transmitted by pupiparous Diptera, such as louse flies (Hippoboscidae) and by bloodsucking midges (Culicoides) [G. haima, blood, + Proteus, a sea god who had the power of assuming different shapes]

Haemosporina
Haemosporina (he′mo-spo-ri′na)

A suborder of coccidia (class Sporozoea) that lack syzygy, with separate development of macrogamete and microgamont, the latter producing eight flagellated microgametes; heteroxenous with merogany in vertebrates and sporogony in bloodsucking insects; includes the genera Haemoproteus, Leucocytozoon, and Plasmodium. [G. haima, blood, + sporos, seed]

Haenszel
Haenszel

William M., U.S. epidemiologist/statistician, 1910–1998. See Mantel-H. test.

Haffkine
Haffkine

Waldemar M.W., Russian physician, 1860–1930. See H. vaccine.

Hafnia
Hafnia (haf′ne-ah)

Genus in the family Enterobacteriaceae; found in human feces, a rare cause of nosocomial infection; associated with diarrheal disease of undefined mechanism. There is a single species, H. alvei.

hafnium
hafnium (Hf) (haf′ne-um)

A rare chemical element, atomic no. 72, atomic wt. 178.49. [L. Hafnia, Copenhagen]

Hagedorn
Hagedorn

Hans Christian, Danish physician, *1888. See NPH insulin.

Hagedorn
Hagedorn

Werner, German surgeon, 1831–1894. See H. needle.

Hageman Hageman

Surname of person in whom deficiency of H. factor was first observed.

hagiotherapy
hagiotherapy (hag′e-o-thar′a-pe)

Treatment of the sick by contact with relics of the saints, visits to shrines, and other religious observances. [G. hagios, sacred]

Haglund
Haglund

S.E. Patrik, Swedish orthopedist, 1870–1937. See H. deformity, H. disease.

Hahnemann
Hahnemann

Christian F.S., German physician and founder of homeopathy, 1755–1843. See hahnemannian.

hahnemannian hahnemannian (hah-ne-mahn′e-an)

Relating to homeopathy as taught by Hahnemann.

Hahn oxine reagent
Hahn oxine reagent

See under reagent.

Haidinger
Haidinger

Wilhelm von, Austrian mineralogist, 1795–1871. See H. brushes, under brush.

Hailey
Hailey

Hugh E., U.S. dermatologist, *1909. See H.-H. disease.

Hailey
Hailey

W. Howard, U.S. dermatologist, 1898–1967. See H.-H. disease.

hair
hair (har) [TA]

1. One of the fine, keratinized filamentous epidermal growths arising from the skin of the body of mammals except the palms, soles, and flexor surfaces of the joints; the full length and texture of h. varies markedly in different body sites. SYN: pilus (1) [TA] . 2. One of the fine, hairlike processes of the auditory cells of the labyrinth, and of other sensory cells, called auditory h., sensory h., etc. SYN: thrix [TA] . [A.S. haer]
auditory hairs cilia on the free surface of the auditory cells.
axillary hairs [TA] h. of the armpit. SYN: hircus (2) .
bamboo h. h. with regularly spaced nodules along the shaft caused by intermittent fractures with invagination of the distal h. into the proximal portion, with intervening lengths of normal h., giving the appearance of bamboo; seen in Netherton syndrome; autosomal recessive trait. SYN: trichorrhexis invaginata.
bayonet h. a spindle-shaped developmental defect occurring at the tapered end of the h..
beaded h. SYN: monilethrix.
burrowing hairs SYN: ingrown hairs.
club h. a h. in resting state, prior to shedding, in which the bulb has become a club-shaped mass.
downy h. [TA] fine, soft, lightly pigmented fetal h. with minute shafts and large papillae; it appears toward the end of the third month of gestation. SYN: lanugo [TA] , primary h.&star, lanugo h..
exclamation point h. the type of dystrophic anagen h. found at margins of patches of alopecia areata; the bulb is absent.
Frey hairs short hairs of varying degrees of stiffness, set at right angles into the end of a light wooden handle; used for assessing sensation.
hairs of head [TA] a h. of the scalp of the head. SYN: scalp h..
ingrown hairs hairs that grow at more acute angles than is normal, and in all directions; they incompletely clear the follicle, turn back in, and cause pseudofolliculitis. SYN: burrowing hairs.
kinky h. tightly curled or bent h.. See kinky-h. disease.
lanugo h. SYN: downy h..
moniliform h. SYN: monilethrix.
nettling hairs sharp-pointed barbed hairs of certain caterpillars which cause a dermatitis when brought in contact with the skin.
primary h. downy h..
pubic h. [TA] one of the pubic hairs; the h. of the pubic region just above the external genitals. SYN: pubes (1) [TA] .
ringed h. a rare condition in which the h. shows alternate pigmented and bright segments, the latter due to air cavities within the cortex. SYN: pili annulati.
scalp h. SYN: hairs of head.
Schridde cancer hairs thick lusterless hairs scattered in the beard and the temporal region, said to occur in cancerous patients but found also in persons with other cachectic conditions.
spun glass h. SYN: uncombable h. syndrome.
stellate h. h. split in several strands at the free end.
taste hairs hairlike projections of gustatory cells of taste buds; electron micrographs show them to be clusters of microvilli.
terminal h. a mature pigmented, coarse h..
hairs of tragus [TA] hairs growing from the tragus of the auricle.
twisted hairs SYN: pili torti, under pilus.
vellus h. colorless, soft, fine postnatal to adult h..
hairs of vestibule of nose [TA] one of the hairs growing at the nares, or vestibule of the nose. SYN: vibrissa [TA] .
woolly h. tightly coiled h., oval in cross-section, with the texture of wool.

hairpin
hairpin ( har′pin)

1. The structure formed by a polynucleic acid by base-pairing between neighboring complementary sequences of a single strand of either DNA or RNA. 2. The structure seen in a prostaglandin where two segments of the molecule fold back on one another.

hairworm
hairworm (har′werm)

See Trichostrongylus, Gordius.

hairy
hairy (har′e)

1. Of or resembling hair. 2. Covered with hair. SEE ALSO: hirsutism. SYN: pilar, pilary, pilose.

halation
halation (ha-la′shun)

Blurring of the visual image by glare.

halazone
halazone (hal′a-zon)

A chloramine used for the sterilization of drinking water.

Halbeisen
Halbeisen

William A., U.S. physician, *1915. See Stryker-H. syndrome.

Halberstaedter
Halberstaedter

Ludwig, German physician, 1876–1949. See H.-Prowazek bodies, under body.

Haldane
Haldane

John B.S., English biochemist and geneticist, 1892–1964. See H. relationship.

Haldane
Haldane

John S., Scottish physiologist at Oxford, 1860–1936. See H. apparatus, H. effect, H. transformation, H. tube, H.-Priestley sample.

Hale colloidal iron stain
Hale colloidal iron stain

See under stain.

Hales
Hales

Stephen, English physiologist, 1677–1761. See H. piesimeter.

half-hapten
half-hapten (haf-hap′ten)

A substance that elicits an antigen-antibody reaction, but no precipitation.

half-life
half-life (haf′lif)

The period in which the radioactivity or number of atoms of a radioactive substance decreases by half; similarly applied to any substance, such as a drug in serum, whose quantity decreases exponentially with time. Cf.:half-time.
biologic half-life the time required for one-half of an amount of a substance to be lost through biologic processes.
effective half-life the time required for the body burden of an administered quantity of radioactivity to decrease by half through a combination of radioactive decay and biologic elimination.
physical half-life the time required for half the atoms of a radionuclide to undergo disintegration.

half-moon
half-moon (haf′moon)

SYN: lunule of nail.
red half-moon irregular red discoloration of the usually pale demilune at the base of the fingernail; may be seen in congestive failure, malignant disease, or liver disease, but not specific for any of these.

half-time
half-time (haf′tim)

The time, in a first-order chemical (or enzymic) reaction, for half of the substance (substrate) to be converted or to disappear. Cf.:half-life.

halfway house
halfway house (haf′wa hows)

A facility for individuals who no longer require the complete facilities of a hospital or institution but are not yet prepared to return to independent living.

halibut liver oil
halibut liver oil (hal′i-but)

The fixed oil obtained from the fresh or suitably preserved livers of halibut species of the genus Hippoglossus (family Pleuronectidae); a supplementary source of vitamins A and D.

halide
halide (hal′id)

A salt of a halogen.

haliphagia
haliphagia (hal-i-fa′je-a)

Ingestion of an excessive quantity of a salt or salts, especially of sodium chloride, calcium, magnesium, or potassium salts, or of sodium bicarbonate. [G. hals, salt, + phago, to eat]

halisteresis
halisteresis (ha-lis-ter-e′sis)

A deficiency of lime salts in the bones. SYN: halosteresis. [G. hals, salt, + steresis, privation, fr. stereo, to deprive]

halisteretic
halisteretic (ha-lis-ter-et′ik)

Relating to or marked by halisteresis.

halitosis
halitosis (hal-i-to′sis)

A foul odor from the mouth. SYN: fetor oris, ozostomia, stomatodysodia. [L. halitus, breath, + G. -osis, condition]

halitus
halitus (hal′i-tus)

Any exhalation, as of a breath or vapor. [L., fr. halo, to breathe]

hallachrome
hallachrome (hal′a-krom)

A quinone intermediate, derived from l-dopa, in the formation of melanin from l-tyrosine.

Hallé
Hallé

Adrien J.M.N., French physician, 1859–1947. See Hallé point.

Haller
Haller

Albrecht von, Swiss physiologist, 1708–1777. See H. ansa, H. anulus, H. arches, under arch, H. circle, H. cones, under cone, H. habenula, H. insula, H. line, H. plexus, H. rete, H. vascular tissue, H. tripod, H. tunica vasculosa, H. unguis, H. vas aberrans.

Hallermann
Hallermann

Wilhelm, German ophthalmologist, 1901–1976. See H.-Streiff syndrome, H.-Streiff-François syndrome.

Hallervorden
Hallervorden

Julius, German neurologist, 1882–1965. See H. syndrome, H.-Spatz disease, H.-Spatz syndrome.

hallex
hallex, pl .hallices (hal′eks, hal′i-sez)

SYN: great toe I. [L.]

Hallgren
Hallgren

Bertil, 20th century Swedish geneticist. See H. syndrome.

Hallopeau
Hallopeau

François H., French dermatologist, 1842–1919. See H. disease.

Hallpike
Hallpike

C.S., 20th century British otologist. See Dix-H. maneuver.

hallucal
hallucal (hal′oo-kal)

Relating to the hallux.

hallucination
hallucination (ha-loo′si-na′shun)

The apparent, often strong subjective perception of an object or event when no such stimulus or situation is present; may be visual, auditory, olfactory, gustatory, or tactile. [L. alucinor, to wander in mind]
auditory h. a symptom frequently observed in a schizophrenic disorder consisting, in the absence of an external source, of hearing a voice or other auditory stimulus that other individuals do not perceive.
command h. a symptom, usually auditory but sometimes visual, consisting of a message, from no external source, to do something.
formed visual h. h. composed of scenes, often landscapes.
gustatory h. the sensation of taste in the absence of a gustatory stimulus; may be seen in temporal lobe epilepsy.
haptic h. the sensation of touch in the absence of stimuli; may be seen in alcoholic delirium tremens.
hypnagogic h. h. occurring when going to sleep in the period between wakefulness and sleep; one of the components of narcolepsy.
hypnopompic h. vivid hallucinations that occur when wakening from sleep; occurs with narcolepsy, but grouped with hypnagogic h..
kinesthesia h. the sense of movement of one or more muscles, when no movement is taking place.
lilliputian h. h. of reduced size of objects or persons.
mood-congruent h. h. in which the content is mood appropriate.
mood-incongruent h. h. that is not consistent with external stimuli; content is not consistent with either manic or depressed mood.
olfactory h. false perception in smell.
stump h. SYN: phantom limb pain.
tactile h. false perception of movement or sensation, as from an amputated limb, or crawling sensation on the skin.
unformed visual h. h. composed of sparks, lights, or bursting spheres of light.

hallucinogen
hallucinogen (ha-loo′si-no-jen)

A mind-altering chemical, drug, or agent, specifically a chemical whose most prominent pharmacologic action is on the central nervous system ( e.g., mescaline); in normal subjects, it elicits optical or auditory hallucinations, depersonalization, perceptual disturbances, and disturbances of thought processes. SYN: psychedelic drug, psychodysleptic drug, psycholytic drug, psychotomimetic drug. [L. alucinor, to wander in mind, + G. -gen, producing]

hallucinogenesis
hallucinogenesis (ha-loo′si-no-jen′e-sis)

The process of producing an hallucination.

hallucinogenic
hallucinogenic (ha-loo′si-no-jen′ik)

SYN: psychedelic.

hallucinosis
hallucinosis (ha-loo-si-no′sis)

A syndrome, usually of organic origin, characterized by more or less persistent hallucinations e.g., alcoholic h..
organic h. the state of experiencing a false sensory perception in the absence of external stimulus observed in individuals with one of the organic mental disorders ( e.g., the frightening sensations experienced in alcoholic h. or by a person who has ingested LSD or another of the mind-altering drugs). See hallucination.

hallus
hallus (hal′us)

SYN: great toe I.

hallux
hallux, pl .halluces (hal′uks, hal′u-sez) [TA]

SYN: great toe I. [a Mod. L. form for L. hallex (hallic-), great toe]
h. dolorosus a condition, usually associated with flatfoot, in which walking causes severe pain in the metatarsophalangeal joint of the great toe. SYN: painful toe.
h. extensus a deformity in which the great toe is held rigidly in the extended position.
h. flexus SYN: h. malleus.
h. malleus hammer toe involving the first toe. SYN: h. flexus.
h. rigidus a condition in which stiffness appears in the first metatarsophalangeal joint; usually associated with the development of bone spurs on the dorsal surface. SYN: stiff toe.
h. valgus a deviation of the tip of the great toe, or main axis of the toe, toward the outer or lateral side of the foot.
h. varus deviation of the main axis of the great toe to the inner side of the foot away from the second toe.

halo
halo (ha′lo)

1. A reddish yellow ring surrounding the optic disk, due to a widening of the scleral ring making the deeper structures visible. 2. An annular flare of light surrounding a luminous body or a depigmented ring around a mole. See h. nevus. 3. SYN: areola (4) . 4. A circular metal band used in a h. cast or h. brace, attached to the skull with pins. [G. halos, threshing floor on which oxen trod a circle; the h. round the sun or moon]
anemic h. pale, relatively avascular areas in the skin seen around vascular spiders, cherry angiomas, and sometimes in acute macular eruptions.
glaucomatous h. 1. a yellowish white ring surrounding the optic disk, indicating atrophy of the choroid in glaucoma; SYN: glaucomatous ring. 2. a h. surrounding lights, caused by corneal edema in glaucoma. SYN: rainbow symptom.
senile h. circumpapillary h. seen in choroidal atrophy of the aged.

haloalkylamines
haloalkylamines (hal-o-al-kil′a-menz)

A class of drugs, including phenoxybenzamine and diabenamine, which binds so as to alkylate α-adrenergic receptors so that they are irreversibly inactivated.

halogen
halogen (hal′o-jen)

One of the chlorine group (fluorine, chlorine, bromine, iodine, astatine) of elements; halogens form monobasic acids with hydrogen, and their hydroxides (fluorine forms none) are also monobasic acids. [G. hals, salt, + -gen, producing]

halogenation
halogenation (hal′o-je-na′shun)

Incorporation of one or more halogen atoms into a molecule.

halogenoderma
halogenoderma (hal-o-gen′o-der-ma)

Dermatosis caused by ingestion or injection of halogens, most notably bromides and iodides. [halogen + G. derma, skin]

Halogeton
Halogeton (hal-o-je′ton)

A genus of plants (family Chenopodiaceae) on range lands in the western U.S. and other arid regions of the world; it causes poisoning in cattle and sheep because of the presence of soluble oxalates.

halometer
halometer (hal-om′e-ter)

An instrument used to measure the diffraction halo of a red blood cell; based on the premise that the halo of the large erythrocyte of pernicious anemia is smaller than that of the normal cell; the hazy colorless halo of normal size is characteristic of secondary anemia.

halophil
halophil, halophile (hal′o-fil, -fil)

A microorganism whose growth is enhanced by or dependent on a high salt concentration. [G. hals, salt, + philos, fond]

halophilic
halophilic (hal-o-fil′ik)

Requiring a high concentration of salt for growth.

halosteresis
halosteresis (ha-los-te-re′sis)

SYN: halisteresis.

halothane
halothane (hal′o-than)

A widely used potent nonflammable and nonexplosive inhalation anesthetic, with rapid onset and reversal; side effects include respiratory and cardiovascular depression, and sensitization to epinephrine-induced arrhythmias. Often used in children, as the odor is less pungent than some other anesthetic agents.

Halstead
Halstead

Ward C., U.S. psychologist, 1908–1968. See H.-Reitan battery.

Halsted
Halsted

William Stewart, U.S. surgeon, 1852–1922. See H. law, H. operation, H. suture.

Halteridium
Halteridium (hawl-te-rid′e-um)

Former name for Haemoproteus. [G. halteres, weights held in the hand in leaping]

halzoun
halzoun (hal′zun)

Local name of a buccopharyngeal infection occurring in Lebanon, probably caused by pentastomid larvae of the dog tongue worm, Linguatula serrata, which wander into the throat of the human host after ingestion of infected raw sheep, or goat liver or lymph nodes. [Ar., snail]

Ham
Ham

Thomas Hale, U.S. physician, 1905–1987. See H. test.

ham
ham

1. SYN: popliteal fossa. 2. The buttock and back part of the thigh. [A.S.]

HAMA
HAMA

Abbreviation for human antimouse antibody.

hamamelis
hamamelis (ham′a-me′lis)

A shrub or small tree, H. virginiana (family Harmarmelidaceae), whose bark and dried leaves have been used externally as an application to contusions and other injuries, in headache, and for the cure of noninflammatory hemorrhoids; the water, popularly known as “extract of witch hazel,” is made from the bark and contains 14% alcohol. SYN: witch hazel. [Mod. L., fr. G. hama- melis, fr. hama, together with, + melon, apple]

hamartia
hamartia (ham-ar′she-a)

A localized developmental disturbance characterized by abnormal arrangement and/or combinations of the tissues normally present in the area. [G. hamartion, a bodily defect]

hamartoblastoma
hamartoblastoma (ha-mar′to-blas-to′ma)

A malignant neoplasm of undifferentiated anaplastic cells thought to be derived from a hamartoma. [hamartoma + blastoma]

hamartochondromatosis
hamartochondromatosis (ham-ar′to-kon′dro-ma-to′sis)

Neoplasm-like foci of cartilaginous tissue in sites where cartilage is a normal constituent, but in which the growth of cartilage cells is out of proportion to the other elements of the organ. [G. hamartion, bodily defect, + chondros, cartilage, + -osis, condition]

hamartoma
hamartoma (ham-ar-to′ma)

A focal malformation that resembles a neoplasm, grossly and even microscopically, but results from faulty development in an organ; composed of an abnormal mixture of tissue elements, or an abnormal proportion of a single element, normally present in that site, which develop and grow at virtually the same rate as normal components, and are not likely to result in compression of adjacent tissue (in contrast to a neoplasm). [G. hamartion, a bodily defect, + -oma, tumor]
fibrous h. of infancy a tumor appearing usually in the upper arm or shoulder in the first two years of life and consisting of cellular fibrous tissue infiltrating the subcutis.
pulmonary h. h. of the lung, producing a coin lesion composed primarily of cartilage and bronchial epithelium.

hamartomatous
hamartomatous (ham-ar-to′ma-tus)

Relating to hamartoma.

hamartophobia
hamartophobia (ham′ar-to-fo′be-a)

Morbid fear of error or sin. [G. hamartia, fault, + phobos, fear]

hamate
hamate

See h. (bone).

hamatum
hamatum (ha-ma′tum)

SYN: hamate (bone). [L. neut. of hamatus, hooked, fr. hamus, a hook]

Hamburger
Hamburger

Hartog J., Dutch physiologist, 1859–1924. See H. phenomenon.

Hamman
Hamman

Louis, U.S. physician, 1877–1946. See H. disease, H. murmur, H. sign, H. syndrome, H.-Rich syndrome.

Hammarsten
Hammarsten

Olof, Swedish physiological chemist, 1841–1932. See H. reagent.

hammer
hammer (ham′er)

SYN: malleus.

Hammerschlag
Hammerschlag

Albert, Austrian physician, 1863–1935. See H. method.

Hammond
Hammond

William A., U.S. neurologist, 1828–1900. See H. disease.

Hampton
Hampton

Aubrey Otis, U.S. radiologist, 1900–1955. See H. line, H. maneuver, H. technique, H. hump.

hamster
hamster

Any of four genera (subfamily Cricetinae, family Muridae) of small rodents widely used in research and as pets: Cricetus, Cricetulus, Mesocricetus, and Phodopus. All hamsters are seed and plant feeders, store food, hibernate in winter, and breed throughout the year under laboratory conditions.

hamstring
hamstring

1. One of the tendons bounding the popliteal space on either side; the medial h. comprises the tendons of the semimembranosus and semitendinosus muscles; the lateral h. is the tendon of the biceps femoris muscle. H. muscles (a) have origin from the ischial tuberosity, (b) act across (at) both the hip and knee joints (producing extension and flexion, respectively), and (c) are innervated by the tibial portion of the sciatic nerve. The medial h. contributes to medial rotation of the leg at the flexed knee joint, while the lateral h. contributes to lateral rotation. 2. In domestic animals, the combined tendons of the superficial digital flexor, triceps surae, biceps femoris, and semitendinosus muscles which are referred to as the common calcanean tendon (tendo calcaneus communis); it is attached to the tuber calcis of the hock.

hamular
hamular (ham′u-lar)

Hook-shaped; unciform. [L. hamulus, q.v.]

hamulus
hamulus, gen. and pl. hamuli (ham′u-lus, -li) [TA]

Any hooklike structure. SYN: hook (2) &star. [L. dim. of hamus, hook]
h. cochleae SYN: h. of spiral lamina.
lacrimal h. [TA] the hooklike lower end of the lacrimal crest, curving between the frontal process and orbital surface of the maxilla to form the upper aperture of the bony portion of the nasolacrimal canal. SYN: h. lacrimalis [TA] , hamular process of lacrimal bone.
h. lacrimalis [TA] SYN: lacrimal h..
h. laminae spiralis [TA] SYN: h. of spiral lamina.
h. ossis hamati [TA] SYN: hook of hamate.
pterygoid h. [TA] the inferior, hook-shaped extremity of the medial plate of the pterygoid process, which serves as a pulley (trochlea) for the tendon of the tensor veli palati muscle. SYN: hamular process of sphenoid bone, h. pterygoideus.
h. pterygoideus SYN: pterygoid h..
h. of spiral lamina [TA] the upper hooklike termination of the bony spiral lamina at the apex of the cochlea. SYN: h. laminae spiralis [TA] , h. cochleae, hook of spiral lamina.

Hancock
Hancock

Henry, English surgeon, 1809–1880. See H. amputation.

Hand
Hand

Alfred, U.S. pediatrician, 1868–1949. See H.-Schüller-Christian disease.

hand
hand [TA]

The portion of the upper limb distal to the radiocarpal joint, comprising the wrist, palm, and fingers. SYN: manus [TA] , main. [A.S.]
accoucheur h. position of the h. in tetany or in muscular dystrophy; the fingers are flexed at the metacarpophalangeal joints and extended at the phalangeal joints, with the thumb flexed and adducted into the palm; in resemblance to the position of the physician's h. in making a vaginal examination. SYN: obstetric h..
ape h. a deformity marked by extension of the thumb in the same plane as the palm and fingers. SYN: monkey h., monkey-paw.
claw h. clawhand.
cleft h. a congenital deformity in which the division between the fingers, especially between the third and fourth, extends into the metacarpal region. SEE ALSO: lobster-claw deformity. SYN: split h..
club h. congenital or acquired angulation deformity of h. associated with partial or complete absence of radius or ulna; usually with intrinsic deformities of the h. in congenital variants.
crab h. SYN: erysipeloid.
dorsum of h. [TA] the back of the h.. SYN: dorsum manus [TA] .
drop h. SYN: wrist-drop.
ghoul h. a condition seen in African blacks, probably a manifestation of tertiary yaws, marked by depigmentation of the palms and contraction of the skin which give a clawlike and corpselike appearance to the hands.
Marinesco succulent h. edema of the h. with coldness and lividity of the skin, observed in syringomyelia. SYN: main succulente.
monkey h. SYN: ape h..
obstetric h. SYN: accoucheur h..
opera-glass h. a deformity of the h. seen in chronic absorptive arthritis, the fingers and wrists being shortened and the covering skin wrinkled into transverse folds; the phalanges appear to be retracted into one another like an opera glass or miniature telescope.
simian h. deformity in which there is flattening of the thenar eminence, and the thumb lies adducted and extended; usually due to a median nerve lesion.
skeleton h. extension of fingers with atrophy of tissues; occurs in progressive muscular atrophy.
spade h. the coarse, thick, square h. of acromegaly or myxedema.
split h. SYN: cleft h..
trident h. a h. in which the fingers are of nearly equal length and deflected at the first interphalangeal joint, so as to give a forklike shape; seen in achondroplasia.
writing h. a contraction of the h. muscles in parkinsonism, bringing the fingers somewhat into the position of holding a pen.

handedness
handedness (hand′ed-nes)

Preference for the use of one hand, most commonly the right, associated with dominance of the opposite cerebral hemisphere; may also be the result of training or habit.

handicap
handicap (hand′i-kap)

1. A physical, mental, or emotional condition that interferes with an individual's normal functioning. 2. Reduction in a person's capacity to fulfill a social role as a consequence of an impairment, inadequate training for the role, or other circumstances. SEE ALSO: disability. [fr. hand in cap, (game)]

handpiece
handpiece (hand′pes)

A powered dental instrument held in the hand, used to hold rotary cutting, grinding, or polishing implements while they are being revolved.

handshapes
handshapes (hand′shaps)

Manual symbols of speech sounds used in cued speech.

HANE
HANE

Acronym for hereditary angioneurotic edema.

hangnail
hangnail (hang′nal)

A loose triangular tag of skin attached proximally in the medial or lateral nail fold.

Hanhart
Hanhart

Ernst, Swiss internist, 1891–1973. See H. syndrome.

Hanks
Hanks

Horace Tracy, U.S. surgeon, 1837–1900. See H. dilators.

Hanks solution
Hanks solution

See under solution.

Hanlon
Hanlon

C. Rollins, U.S. cardiovascular and thoracic surgeon, *1915. See Blalock-H. operation.

Hannover
Hannover

Adolph, Danish anatomist, 1814–1894. See H. canal.

Hanot
Hanot

Victor C., French physician, 1844–1896. See H. cirrhosis.

Hansen
Hansen

Gerhard A., Norwegian physician, 1841–1912. See H. bacillus, H. disease.

Hantavirus
Hantavirus (han′ta-va-rus)

A genus of Bunyaviridae responsible for pneumonia and hemorrhagic fevers. At least 7 members of the genus are thus far recognized: Hantaan, Puumala, Seoul, Prospect Hill, Thailand, Thottapalayam, and Sin Nombre virus. A number of other species have not been classified as yet. Hantaan virus causes Korean hemorrhagic fever. Various rodent species are the asymptomatic carriers of these viruses, which are shed in saliva, urine, and feces. Human infection is direct, or by the respiratory route from contaminated specimens; person-to-person spread is thought to be rare. An outbreak of h. infection, the H. Pulmonary Syndrome (HPS), causing severe and often fatal pulmonary symptoms was identified in the Four-Corners region of the western U.S. in 1993 and the agent was subsequently named Sin Nombre virus.

hapalonychia
hapalonychia (hap′a-lo-nik′e-a)

Thinning of nails resulting in bending and breaking of the free edge, with longitudinal fissures. SYN: egg shell nail. [G. hapalos, soft + G. onyx (onych-), nail]

haphalgesia
haphalgesia (haf-al-je′ze-a)

Pain or an extremely disagreeable sensation caused by the merest touch. SYN: Pitres sign (1) . [G. haphe, touch, + algesis, sense of pain]

haphazard
haphazard

Lacking any coherent system, organization, or objective; not to be confused with random or chaotic.

haphephobia
haphephobia (haf-e-fo′be-a)

A morbid dislike or fear of being touched. [G. haphe, touch, + phobos, fear]

haplo- haplo-

Simple, single. [G. haplous]

haplodont
haplodont (hap′lo-dont)

Having molar teeth with simple crowns, i.e., simple conical teeth without ridges or tubercles. [haplo- + G. odous, tooth]

haploid
haploid (hap′loyd)

Denoting the number of chromosomes in sperm or ova, which is half the number in somatic (diploid) cells; the h. number in normal human beings is 23. SYN: monoploid. [G. haplos, simple, + eidos, appearance]

haplology
haplology (hap-lol′o-je)

The omission of syllables because of excessive speed of utterance. [haplo- + G. logos, study]

haploprotein
haploprotein (hap-lo-pro′ten)

The functional complex between an apoprotein and the prosthetic group that together are responsible for biologic activity.

haploscope
haploscope (hap′lo-skop)

An instrument for presenting separate views to each eye so that they may be seen as one. [haplo- + G. skopeo, to view]
mirror h. a h. using mirrors to displace the field of view of the two eyes, as in Worth amblyoscope and the synoptophore.

haploscopic
haploscopic (hap-lo-skop′ik)

Relating to a haploscope.

Haplosporidia
Haplosporidia (hap′lo-spo-rid′e-a)

An order of sporozoans, now placed in the protozoan phylum Ascetospora, class Stellatosporea, that reproduce asexually by schizogony and produce spores but no flagella, though pseudopodia may be present. [haplo- + G. sporos, seed]

haplotype
haplotype (hap′lo-tip)

1. The genetic constitution of an individual with respect to one member of a pair of allelic genes; individuals are of the same h. (but of different genotypes) if alike with respect to one allele of a pair but different with respect to the other allele of a pair. 2. In immunogenetics, that portion of the phenotype determined by a set of closely linked genes inherited from one parent ( i.e., genes located on one of the pair of chromosomes). [haplo- + G. typos, impression, model]

hapten
hapten (hap′-ten)

A molecule that is incapable, alone, of causing the production of antibodies but can, however, combine with a larger antigenic molecule called a carrier. A h.-carrier complex can stimulate production of antibodies, some of which combine with the h. portion of the complex. SEE ALSO: h. inhibition of precipitation. SYN: incomplete antigen, partial antigen. [G. hapto, to fasten, bind]
conjugated h. a h. that may cause the production of antibodies when it has been covalently linked to protein. SYN: conjugated antigen.
Forssman h. a glycolipid from mammalian organs; it is a ceramide pentasaccharide. Cf.:Forssman antibody, Forssman antigen.
half h. half-h..

haptodysphoria
haptodysphoria (hap′to-dis-fo′re-a)

An unpleasant sensation derived from touching certain objects. [G. hapto, to touch, + dysphoria]

haptoglobin
haptoglobin (HP) (hap-to-glo′bin) [MIM*140100 & MIM*140210]

A group of α₂-globulins in human serum, so called because of their ability to combine with hemoglobin, preventing loss in the urine; variant types form a polymorphic system, with α- and β-polypeptide chains controlled by separate genetic loci. Levels are decreased in hemolytic disorders and increased in inflammatory conditions or with tissue damage. [G. hapto, to grasp, + hemoglobin]

haptometer
haptometer (hap-tom′e-ter)

Instrument for measuring sensitivity to touch. [G. hapto, to touch, + metron, measure]

Har
Har

Abbreviation for homoarginine.

Harada
Harada

Einosuke, Japanese surgeon, 1892–1947. See H. disease, H. syndrome, H.-Ito procedure.

Harada
Harada

T., 20th century Japanese pathologist. See H.-Mori filter paper strip culture.

Harden
Harden

Sir Arthur, English biochemist and Nobel laureate, 1865–1940. See H.-Young ester.

hardening
hardening (har′den-ing)

1. A condition of lessened reactions to allergens from repeated or prolonged nontherapeutic exposure, similar to hyposensitization. 2. Any procedure in tissue preparation for examinations, such as sectioning for microscopy, that renders the tissue firmer.

hardiness
hardiness (har′di-nes)

A health-enhancing behavior trait believed to increase one's resistance to illness, characterized by a high level of personal control, commitment, and action in responding to events of daily life. [M.E., fr. O.Fr. hardi, fr. Germanic]

Harding
Harding

Harold E., 20th century British pathologist. See H.-Passey melanoma.

hardness
hardness (hard′nes)

1. The degree of firmness of a solid, as determined by its resistance to deformation, scratching, or abrasion. SEE ALSO: h. scale, number. 2. The relative penetrating power of a beam of x-rays, used both within the diagnostic range of energy and in radiation therapy; expressed in terms of half-value layer.
indentation h. a number related to the size of the impression made by an indenter (or tool) of specific size and shape under a known load.

hardware
hardware

The electronic component of a computer.

Hardy
Hardy

George H., English mathematician, 1877–1947. See H.-Weinberg equilibrium, H.-Weinberg law.

Hardy
Hardy

LeGrand H., U.S. ophthalmologist, 1894–1954. See H.-Rand-Ritter test.

harelip
harelip (har′lip)

SYN: cleft lip.

harmaline
harmaline (har′ma-lin)

An amine oxidase inhibitor and a central nervous system stimulant; obtained from the seeds of Peganum harmala (family Zygophyllaceae) and from Banisteria caapi (family Malpighiaceae); has been used in parkinsonism. SYN: harmidine.

harmidine
harmidine (har′mi-den)

SYN: harmaline.

harmine
harmine (har′men)

A central nervous system stimulant and potent monoamine oxidase inhibitor obtained from Peganum harmala (family Zygophyllaceae) and Banisteria caapi (family Malpighaceae); psychic effects resemble those of LSD, but sedative and depressive qualities may predominate over hallucinatory manifestations. SYN: banisterine, leucoharmine, telepathine. [G. harmala, harmal, fr. Ar. harmalah, + -ine]

harmonia
harmonia (har-mo′ne-a)

SYN: plane suture. [L. and G. a joining]

harmonic
harmonic (har-mon′ik)

A component of complex sound, the frequency of which is a multiple of the fundamental frequency. The fundamental frequency is called the first h.; the second h. has twice the frequency of the fundamental, and so forth.

harmony
harmony (har′mo-ne)

Denoting, in a complex sound, a mathematical relationship among the frequencies of the fundamental tone and its overtones so that the frequencies of the overtones are whole number multiples or partials of the frequency of the fundamental tone; the resulting auditory effect has a musical or pleasant quality, as opposed to noise. [G., L. harmonia, agreement, articulation, fr. harmos, joint]
functional occlusal h. such occlusal relationship of opposing teeth in all functional ranges and movements as will provide the greatest masticatory efficiency without causing undue strain or trauma upon the supporting tissues, teeth, and muscles.
occlusal h. occlusion without deflective or interceptive occlusal contacts in centric jaw relation as well as eccentric movements.

harpaxophobia
harpaxophobia (har′paks-o-fo′be-a)

Morbid fear of robbers. [G. harpax, robber, + phobos, fear]

harpoon
harpoon (har-poon′)

A small, sharp-pointed instrument with a barbed head used for extracting bits of tissue for microscopic examination.

Harrington
Harrington

David O., U.S. ophthalmologist, *1904. See H.-Flocks test.

Harris
Harris

Henry A., English anatomist, 1886–1968. See H. lines, under line.

Harris
Harris

Henry F., U.S. physician, 1867–1926. See H. hematoxylin.

Harris
Harris

R.I., 20th century Canadian orthopedist. See Salter-H. classification of epiphysial plate injuries.

Harris
Harris

Seale, U.S. physician, 1870–1957, investigated food conditions and nutritional diseases. See H. syndrome.

Harris
Harris

Wilfred, English neurologist, 1869–1960. See H. migraine.

Harrison
Harrison

Edward, English physician, 1766–1838. See H. groove.

Harris and Ray test
Harris and Ray test

See under test.

Hartel
Hartel

Fritz, German surgeon. See H. technique.

Hartman
Hartman

LeRoy L., U.S. dentist, 1893–1951. See H. solution.

Hartmann
Hartmann

Alexis F., U.S. pediatrician, 1898–1964. See H. solution, Shaffer-H. method.

Hartmann
Hartmann

Arthur, German laryngologist, 1849–1931. See H. curette.

Hartmann
Hartmann

Henri A.C.A., French surgeon, 1860–1952. See H. operation, H. pouch.

Hartmannella
Hartmannella (hart-ma-nel′a)

A common free-living ameba found in soil, sewage, and water, known to invade invertebrates (snails, grasshoppers, oysters); suspected but not established as an agent of human primary amebic meningoencephalitis.

Hartnup Hartnup

Surname of British family in which the disease was first described. See H. disease, H. syndrome.

hartshorn
hartshorn (harts′horn)

A mixture of ammonium bicarbonate and ammonium carbamate obtained from ammonium sulfate and calcium carbonate by sublimation; used as an expectorant and in smelling salts; so called because originally obtained from deer antlers.

harvest bug
harvest bug

The larva of Trombicula species.

Harvey
Harvey

William, 1578–1657. English anatomist, physiologist, and physician who first described the circulation of the blood in 1628. He understood that the interventricular septum is not porous so blood cannot pass through it. He demonstrated the volume of blood that passes unidirectionally through a segment of a peripheral vein exceeds the volume of blood within the body, so blood must recirculate. He described the organization of the fetal circulation and the transition to the postnatal organization.

hasamiyami
hasamiyami (has′a-me-yah′me)

A fever occurring in Japan in the autumn; resembles Weil disease, but is milder and is caused by the autumnalis serovar of Leptospira interrogans. SYN: akiyami, autumn fever (2) , sakushu fever, seven-day fever (2) .

Häser
Häser

Heinrich, German physician, 1811–1884. See H. formula, Trapp-H. formula.

Hashimoto
Hashimoto

Japanese surgeon, 1881–1934. See H. disease, H. struma, H. thyroiditis.

hashish
hashish (hash′ish)

A form of cannabis that consists largely of resin from the flowering tops and sprouts of cultivated female plants; contains the highest concentration of cannabinols among the preparations derived from cannabis. [Ar. hay]

Hasner
Hasner

Joseph Ritter von, Czechoslovakian ophthalmologist, 1819–1892. See H. fold.

Hassall
Hassall

Arthur, British physician, 1817–1894. See H. bodies, under body, H. concentric corpuscle, under corpuscle, H.-Henle bodies, under body, Virchow-H. bodies, under body.

Hasselbalch
Hasselbalch

Karl, Danish biochemist and physician, 1874–1962. See Henderson-H. equation.

hatchet
hatchet

A dental instrument with an end cutting blade set at an angle to the axis of the handle and having one or two bevels; in the former case, made as right and left pairs called enamel hatchets; used for removing enamel and dentin on teeth.

Haubenfelder
Haubenfelder (how′ben-fel′der)

See fields of Forel, under field. [Ger.]

Hauch
Hauch (H) (howkh)

A term used to designate the flagellar antigen of bacteria. SEE ALSO: H antigen. [Ger. breath]

Haudek
Haudek

Martin, Austrian roentgenologist, 1880–1931. See H. niche.

Hauser
Hauser

G.A., 20th century German gynecologist. See Mayer-Rokitansky-Küster-H. syndrome, Rokitansky-Küster-H. syndrome.

haustorium
haustorium, pl .haustoria (haw-sto′re-um, -sto′re-a)

An organ for the absorption of nutriment. [Mod. L. fr. L. haustus, a drinking]

haustra
haustra (haw′stra)

Plural of haustrum. [L.]

haustral
haustral (hos′tral)

Relating to a haustrum.

haustration
haustration (hos′tra′shun)

1. The process of formation of a haustrum. 2. An increase in prominence of the haustra.
haustrations of colon SYN: haustra of colon, under haustrum.

haustrum
haustrum, pl .haustra (hos′trum, haw′stra) [TA]

One of a series of saccules or pouches, so called because of a fancied resemblance to the buckets on a water wheel. [L. a machine for drawing water, fr. haurio, pp. haustus, to draw up, drink up]
haustra coli [TA] SYN: haustra of colon.
haustra of colon [TA] the sacculations of the colon, caused by the teniae, or longitudinal bands, which are slightly shorter than the gut so that the latter is thrown into tucks or pouches. SYN: haustra coli [TA] , cellulae coli, haustrations of colon, sacculation of colon.

haustus
haustus (haws′tus)

A potion or medicinal draft. [L. a drink, draft]

HAV
HAV

Abbreviation for hepatitis A virus.

Haverhillia multiformis
Haverhillia multiformis (ha-ver-hil′e-a mul-ti-for′mis)

See Streptobacillus moniliformis.

Havers
Havers

Clopton, British anatomist, 1650–1702. See haversian canals, under canal, haversian lamella, haversian spaces, under space, haversian system.

haversian haversian (ha-ver′shan)

Relating to Clopton Havers and the various osseous structures described by him.

Hawley
Hawley

C.A., U.S. orthodontist. See H. appliance, H. retainer.

Haworth
Haworth

Sir Walter Norman, British chemist and Nobel laureate, 1883–1950. See H. conformational formulas of cyclic sugars, H. perspective formulas of cyclic sugars.

Hayem
Hayem

Georges, French physician, 1841–1933. See H. hematoblast, H. solution, H.-Widal syndrome.

Hayflick
Hayflick

Leonard, U.S. microbiologist, *1928. See H. limit.

Haygarth
Haygarth

John, English physician, 1740–1827. See H. nodes, under node.

hazelwort
hazelwort (ha′zel-wort)

SYN: Asarum europaeum.

Hb
Hb

Abbreviation for hemoglobin.

HbChesapeake
Hb_Chesapeake

Abbreviation for hemoglobin Chesapeake.

HBeAb
HB_eAb

Abbreviation for antibody to the hepatitis B e antigen.

HBsAb
HB_sAb

Abbreviation for antibody to the hepatitis B surface antigen.

HBcAb
HB_cAb

Abbreviation for antibody to the hepatitis B core antigen.

HBsAg
HB_sAg

Abbreviation for hepatitis B surface antigen.

HBcAg
HB_cAg

Abbreviation for hepatitis B core antigen.

HbCO
HbCO

Abbreviation for carboxyhemoglobin.

HBE
HBE

Abbreviation for His bundle electrogram.

HBe
HBe, HB_eAg

Abbreviation for hepatitis B e antigen.

HbO2
HbO₂

Abbreviation for oxyhemoglobin.

Hb S
Hb S

Abbreviation for sickle cell hemoglobin.

HBV
HBV

Abbreviation for hepatitis B virus.

HCC
HCC

Abbreviation for 25-hydroxycholecalciferol.

HCFA
HCFA

Abbreviation for Health Care Financing Administration.

HCG
HCG, hCG

Abbreviation for human chorionic gonadotropin.

H chain
H chain

SYN: heavy chain.

HCS
HCS

Abbreviation for human chorionic somatomammotropic hormone; human chorionic somatomammotropin.

Hct
Hct

Abbreviation for hematocrit.

HCV
HCV

Abbreviation for hepatitis C virus.

Hcy
Hcy

Abbreviation for homocysteine.

HD
HD

Abbreviation for mustard gas.

h.d.
h.d.

Abbreviation for L. hora decubitus, at bedtime.

HDCV
HDCV

Abbreviation for human diploid cell vaccine; human diploid cell rabies vaccine.

HDL
HDL

Abbreviation for high density lipoprotein. See lipoprotein.

HDV
HDV

Abbreviation for hepatitis delta virus.

He
He

Symbol for helium.

3He
³He, ⁴He

Symbols for helium-3 and helium-4, respectively.

Head
Head

Sir Henry, English neurologist, 1861–1940. See H. areas, under area, H. lines, under line, H. zones, under zone.

head
head (hed) [TA]

1. [TA] The upper or anterior extremity of the animal body, containing the brain and the organs of sight, hearing, taste, and smell. 2. [TA] The upper, anterior, or larger extremity, expanded or rounded, of any body, organ, or other anatomic structure. 3. The rounded extremity of a bone. 4. That end of a muscle that is attached to the less movable part of the skeleton. SYN: caput [TA] . [A.S. heafod]
bulldog h. the broad h. with high vault occurring in achondroplasia.
h. of caudate nucleus [TA] the h. or anterior extremity of the caudate nucleus projecting into the anterior horn of the lateral ventricle. SYN: caput nuclei caudati [TA] , anterior extremity of caudate nucleus.
clavicular h. of pectoralis major muscle [TA] See pectoralis major (muscle). SYN: pars clavicularis musculi pectoralis majoris [TA] , clavicular part of pectoralis major (muscle).
deep h. of flexor pollicis brevis [TA] the h. of short flexor of the thumb that arises from the trapezoid and capitate bones and transverse carpal ligaments. It is innervated by the deep ulnar nerve, and considered by many to be the first palmar interosseous muscle. SYN: caput profundum musculi flexoris pollicis brevis [TA] .
h. of epididymis [TA] the upper and larger extremity of the epididymis. SYN: caput epididymidis [TA] , caput epididymis, globus major.
h. of femur [TA] the hemispheric articular surface at the upper extremity of the thigh bone. SYN: caput femoris [TA] , caput ossis femoris, h. of thigh bone.
h. of fibula [TA] the superior extremity of the fibula, which articulates by a facet with the undersurface of the lateral condyle of the tibia. SYN: caput fibulae [TA] , upper extremity of fibula.
hourglass h. in congenital syphilis, a skull with depressed coronal suture.
humeral h. [TA] the name applied to the heads of forearm muscles that attach to the humerus. Terminologia Anatomica lists humeral heads (caput humerale ...) of the following: 1) flexor carpli ulnaris (... musculi flexoris carpi ulnaris [TA]); 2) pronator teres (... musculi pronatoris teretis [TA]); and 3) extensor carpi ulnaris (...musculi extensoris carpi ulnaris [TA]). SYN: caput humerale [TA] .
humeroulnar h. of flexor digitorum superficialis muscle [TA] the h. of the superficial flexor of the digits that attaches to both the humerus and the ulna. SYN: caput humeroulnare musculi flexoris digitorum superificialis [TA] .
h. of humerus [TA] the upper rounded extremity fitting into the glenoid cavity of the scapula. SYN: caput humeri [TA] .
lateral h. [TA] h. of origin farthest from the midline. Terminologia Anatomica lists lateral heads (caput laterale ...) of the following: 1) triceps brachii (... musculi tricipitis brachii [TA]); 2) gastrocnemius (... musculi gastrocnemii [TA]); and 3) flexor hallucis brevis (...musculi flexoris hallucis brevis [TA]). SYN: caput laterale [TA] .
little h. of humerus SYN: capitulum of humerus.
long h. [TA] the h. that has the more proximal origin. Terminologia Anatomica lists long heads (caput longum ...) of the following: 1) biceps brachii (... musculi bicipitis brachii [TA]); 2) biceps femoris (... musculi bicipitis femoris [TA]); and 3) triceps brachii (... musculi tricipitis brachii [TA]). SYN: caput longum [TA] .
h. of malleus [TA] the rounded portion of the malleus articulating with the body of the incus. SYN: caput mallei [TA] .
h. of mandible [TA] the expanded articular portion of the condylar process of the mandible. SYN: caput mandibulae [TA] .
medial h. [TA] the h. of origin closest to the midline. Terminologia Anatomica lists medial h. (caput mediale) of the following: 1) triceps brachii (... musculi tricipitis brachii [TA]); 2) gastrocnemius (... musculi gastrocnemii [TA]); and 3) flexor hallucis brevis (... musculi flexoris hallucis brevis [TA]). SYN: caput mediale [TA] .
Medusa h. SYN: caput medusae.
h. of metacarpal [TA] the expanded distal end of a metacarpal that articulates with the proximal phalanx of the same digit. SYN: caput ossis metacarpalis [TA] .
h. of metatarsal [TA] the expanded distal end of a metatarsal bone that articulates with the proximal phalanx of the same digit. SYN: caput ossis metatarsalis [TA] .
oblique h. [TA] h. of origin which is diagonally situated. Terminologia Anatomica lists oblique heads (caput obliquum ...) of the following: 1) adductor hallucis (... musculi adductoris hallucis [TA]); and 2) adductor pollicis (... musculi adductoris pollicis [TA]). SYN: caput obliquum [TA] .
optic nerve h. SYN: optic disk.
h. of pancreas [TA] that portion of the pancreas lying in the concavity of the duodenum. SYN: caput pancreatis [TA] .
h. of phalanx (of hand or foot) [TA] the rounded articular surface at the distal end of the proximal and middle phalanx of each finger and toe. SYN: caput phalangis (manus et pedis) [TA] .
h. of radius [TA] the disk-shaped upper extremity articulating with the capitulum of the humerus. SYN: caput radii [TA] .
h. of rib [TA] the rounded medial extremity of a rib that, except for ribs 1, 10, 11, and 12, articulates by two facets with the bodies of two contiguous vertebrae. SYN: caput costae [TA] .
saddle h. SYN: clinocephaly.
short h. [TA] for a muscle with two heads of origin (a “biceps” muscle), the h. originating nearest the insertion. See short h. of biceps brachii, short h. of biceps femoris. SYN: caput breve [TA] .
short h. of biceps brachii [TA] h. of biceps brachii originating from coracoid process of scapula. SYN: caput breve musculi bicipitis brachii [TA] .
short h. of biceps femoris [TA] part of biceps femoris originating from linea aspera of distal half of femur. SYN: caput breve musculi bicipitis femoris [TA] .
h. of stapes [TA] the portion of the stapes that articulates with the lenticular process of the incus. SYN: caput stapedis [TA] .
sternocostal h. of pectoralis major (muscle) [TA] portion of pectoralis major (muscle) originating from the sternum and ribs; acting alone the ternocostal part extends the arm at the shoulder joint; acting with the clavicular h. it adducts the arm. See pectoralis major (muscle). SYN: pars sternocostalis musculi pectoralis majoris [TA] , sternocostal part of pectoralis major muscle.
superficial h. of flexor pollicis brevis [TA] the h. of the short flexor of the thumb that arises from the transverse carpal ligament (flexor retinaculum) and the trapezium. It is innervated by the recurrent branch of the median nerve. SYN: caput superficiale musculi flexoris pollicis brevis [TA] .
h. of talus [TA] the rounded anterior portion of the talus articulating with the navicular bone. SYN: caput tali [TA] .
h. of thigh bone SYN: h. of femur.
transverse h. [TA] h. of origin of a muscle that is transversely situated. Terminologia Anatomica lists transverse heads (caput transversum ...) of the following: 1) adductor hallucis (... musculi adductoris hallucis [TA]); and 2) adductor pollicis (... musculi adductoris pollicis [TA]). SYN: caput transversum [TA] .
h. of ulna [TA] the small rounded distal extremity of the ulna articulating with the ulnar notch of the radius and the articular disk. SYN: caput ulnae [TA] .
ulnar h. [TA] the name applied to a h. of origin of a forearm muscle arising from the ulna. Terminologia Antomica lists ulnar heads (caput ulnare ...) of the following: 1) flexor carpi ulnaris (... musculi flexoris carpi ulnaris [TA]); 2) pronator teres (... musculi pronatoris teritis [TA]); and 3) extensor carpi ulnaris (... musculi extensoris carpi ulnaris [TA]). SYN: caput ulnare [TA] .

headache
headache (hed′ak)

Pain in various parts of the head, not confined to the area of distribution of any nerve. SEE ALSO: cephalodynia. SYN: cephalalgia, encephalalgia, encephalodynia.
benign exertional h. h. occurring with exertion or straining in the absence of any intracranial disease.
bilious h. SYN: migraine.
blind h. SYN: migraine.
cluster h. possibly due to a hypersensitivity to histamine; characterized by recurrent, severe, unilateral orbitotemporal headaches associated with ipsilateral photophobia, lacrimation, and nasal congestion. SYN: histaminic cephalalgia, histaminic h., Horton cephalalgia, Horton h..
coital h. a form of benign exertional h. occurring during sexual activity. SYN: benign coital cephalalgia.
fibrositic h. h. centered in the occipital region due to fibrositis of the occipital muscles; tender areas are present and, commonly, tender nodules are found in the scalp in the lower occipital region.
histaminic h. SYN: cluster h..
Horton h. SYN: cluster h..
ice pick h. SYN: idiopathic stabbing h..
idiopathic stabbing h. brief repetitive sharp pains in the temporal-parietal area of the head. SYN: ice pick h..
migraine h. migraine.
muscle contraction h. SYN: tension h..
nodular h. radiating pain in the head accompanied by nodular swellings in the splenius, frontalis, trapezius, and other muscles.
organic h. h. due to intracranial disease.
posttraumatic h. h. following trauma to the head or neck.
reflex h. SYN: symptomatic h..
sick h. SYN: migraine.
spinal h. h., usually frontal or occipital, that follows lumbar puncture; precipitated by patient's sitting or standing, and relieved by lying down; due to leakage of cerebrospinal (CSF) fluid through the puncture site, with resulting reduction in CSF pressure and traction on the dural and cerebral vessels. SYN: post–lumbar puncture syndrome.
symptomatic h. a h. secondary to another organic condition. SYN: reflex h..
tension h. h. associated with nervous tension, anxiety, etc., often related to chronic contraction of the scalp muscles. SEE ALSO: posttraumatic neck syndrome. SYN: muscle contraction h., tension-type h..
tension-type h. SYN: tension h..
thunderclap h. sudden severe nonlocalizing head pain not associated with any abnormal neurological findings; of varied etiology, including subarachnoid hemorrhage, migraine, carotid or vertebral artery dissection, cavernous sinus thrombosis, and idiopathic.
vacuum h. h. due to closure of the frontal sinus.
vascular h. SYN: migraine.

headgear
headgear (hed′ger)

A removable extraoral appliance used as a source of traction to apply force to the teeth and jaws.

headgut
headgut (hed′gut)

SYN: foregut.

head-nodding
head-nodding (hed′nod-ing)

Head movements associated with congenital nystagmus, spasmus nutans, and miner's nystagmus. SYN: head tremors.

head-tilt
head-tilt (hed′tilt)

An abnormal position of the head adopted to prevent double vision resulting from underaction of the vertical ocular muscles.

heal
heal (hel)

1. To restore to health, especially to cause an ulcer or wound to cicatrize or unite. 2. To become well, to be cured; to cicatrize or close, said of an ulcer or wound. [A.S. healan]

healer
healer (he′ler)

1. A physician; one who heals or cures. 2. One who claims to cure by prayer, mysticism, new thought, or other form of suggestion.

healing
healing (hel′ing)

1. Restoring to health; promoting the closure of wounds and ulcers. 2. The process of a return to health. 3. Closing of a wound. SEE ALSO: union.
faith h. a treatment utilized since antiquity based upon prayer and a profound belief in divine intervention in human affairs.
h. by first intention h. by fibrous adhesion, without suppuration or granulation tissue formation. SYN: primary adhesion, primary union.
h. by second intention delayed closure of two granulating surfaces. SYN: secondary adhesion, secondary union.
h. by third intention the slow filling of a wound cavity or ulcer by granulations, with subsequent cicatrization.

health
health (helth)

1. The state of the organism when it functions optimally without evidence of disease or abnormality. 2. A state of dynamic balance in which an individual's or a group's capacity to cope with all the circumstances of living is at an optimum level. 3. A state characterized by anatomic, physiologic, and psychologic integrity, ability to perform personally valued family, work, and community roles; ability to deal with physical, biologic, psychologic, and social stress; a feeling of well-being; and freedom from the risk of disease and untimely death. [A.S. haelth]
behavioral h. an interdisciplinary field dedicated to promoting a philosophy of h. that stresses individual responsibility in the application of behavioral and biomedical science knowledge and techniques to the maintenance of h. and prevention of illness and dysfunction by a variety of self-initiated individual and shared activities.
h. education process by which individuals and groups learn to behave in a manner conducive to promotion, maintenance, or restoration of h..
mental h. emotional, behavioral, and social maturity or normality; the absence of a mental or behavioral disorder; a state of psychological well-being in which one has achieved a satisfactory integration of one's instinctual drives acceptable to both oneself and one's social milieu; an appropriate balance of love, work, and leisure pursuits.
public h. the art and science of community h., concerned with statistics, epidemiology, hygiene, and the prevention and eradication of epidemic diseases; an effort organized by society to promote, protect, and restore the people's h.; public h. is a social institution, a service, and a practice.

Health Care Financing Administration
Health Care Financing Administration (HCFA)

The federal agency that determines reimbursement for federal programs.

health center
health center

An institution or group of institutions providing all types of medical care and preventive services to a population.

Health Resources and Services Administration
Health Resources and Services Administration (HRSA)

A federal agency responsible for managing national data banks, such as the National Practitioner Data Bank, as well as other health care programs.

healthy
healthy (helth′e)

Well; in a state of normal functioning; free from disease.

Heaney
Heaney

Noble Sproat, U.S. gynecological surgeon and obstetrician, 1880–1955. See H. operation.

hear
hear (her)

To perceive sounds; denoting the function of the ear. [A.S. heran]

hearing
hearing (her′ing)

The ability to perceive sound; the sensation of sound as opposed to vibration. SYN: audition.
color h. a subjective perception of color produced by certain sounds. SEE ALSO: pseudochromesthesia. SYN: chromatic audition.
normal h. SYN: acusis.

hearing aid
hearing aid (her′ing ad)

An electronic amplifying device designed to bring sound into the ear; it consists of a microphone, amplifier, and receiver. SYN: hearing instrument.
behind-the-ear h. h. that rests on the medial aspect of the pinna.
completely in the canal h. (CIC) a h. that fits entirely in the external auditory canal and is not visible at the surface of the body.
digital h. programmable h. that can be customized to the extent of the user's hearing loss.
in-the-canal h. h. that is placed in the external auditory canal but is still visible.
in-the-ear h. h. that fits into the shell of the ear.

hearing impairment
hearing impairment, hearing loss

A reduction in the ability to perceive sound; may range from slight inability to complete deafness. SEE ALSO: deafness, threshold shift.
acoustic trauma hearing loss sensory hearing loss due to exposure to high-intensity noise.
Alexander h. [MIM*203500] high frequency deafness due to membranous cochlear dysplasia.
boilermaker's hearing loss SYN: noise-induced hearing loss.
conductive h. a form of h. due to a lesion in the external auditory canal or middle ear.
functional h. SYN: psychogenic h..
hereditary h. h. occurring in syndromic forms (in which there are other anomalies in addition to the h.) and nonsyndromic forms (in which h. is the only unusual finding) with autosomal dominant and recessive, X-linked, and mitochondrial modes of transmission; may be congenital, of early onset in childhood, or late onset in mid-life and advanced age.
high-frequency h. selective loss of hearing for high frequencies, usually associated with sensory damage; common in acoustic trauma and noise-induced hearing loss.
hysterical h. SYN: psychogenic h..
industrial hearing loss SYN: noise-induced hearing loss.
low-tone hearing loss inability to hear low notes or frequencies.
mixed hearing loss combination of conductive and sensorineural hearing loss.
Mondini h. the h. resulting from the structural aberration of Mondini dysplasia.
neural hearing loss form of sensorineural hearing loss due to a lesion in the auditory division of the 8th cranial nerve.
noise-induced hearing loss sensory hearing loss due to exposure to intense impulse or continuous sound. SYN: boilermaker's hearing loss, industrial hearing loss, occupational hearing loss.
occupational hearing loss SYN: noise-induced hearing loss.
organic h. deafness due to a pathologic process or an organic cause, as opposed to psychogenic h..
perceptive h. former term for sensorineural deafness.
psychogenic h. h. without evidence of organic cause; often follows severe psychic shock. SYN: functional h., hysterical h..
retrocochlear hearing loss term for sensorineural h.; suggesting a lesion proximal to the cochlea.
Scheibe h. h. due to cochleosaccular dysplasia; usually autosomal recessive inheritance.
sensorineural hearing loss a form of hearing loss due to a lesion of the auditory division of the 8th cranial nerve or the inner ear.
sensory h. form of sensorineural h. caused by a lesion in the inner ear.

heart
heart (hart) [TA]

A hollow muscular organ that receives the blood from the veins and propels it into the arteries. In mammals it is divided by a musculomembranous septum into two halves—right or venous and left or arterial—each of which consists of a receiving chamber (atrium) and an ejecting chamber (ventricle). SYN: cor [TA] , coeur. [A.S. heorte]
armor h. extensive to complete calcification (rarely ossification) of the pericardium usually producing constrictive pericarditis.
armored h. calcareous deposits in the pericardium due to subacute or chronic pericarditis. SYN: panzerherz.
artificial h. a mechanical pump used to replace the function of a damaged h., either temporarily or as a permanent prosthesis.
athlete's h. a more or less loose designation for cardiac findings in healthy athletes that would be or could be abnormal in patients with disease, including atrioventricular blocks, left ventricular hypertrophy and, sometimes, benign arrhythmias and atrioventricular blocks.
athletic h. hypertrophy of the h. supposedly due to systematic athletic conditioning.
beer h. SYN: alcoholic cardiomyopathy.
beriberi h. h. disease due to thiamine deficiency that may be epidemic or sporadic as characterized by cardiac metabolic damage and myocardial failure, often of the “high output” type, with edema (except in “dry” shoshin beriberi) and polyneuritis. The term is derived from Singhalese, “I am unable.”
bony h. the presence of extensive calcareous patches in the pericardium and walls of the h., some of which chronically develop bony changes.
chaotic h. apparently totally uncoordinated cardiac action or rhythm.
crisscross h. an anomaly in which the ventricular relationships are not as expected for the given atrioventricular connection.
drop h. SYN: cardioptosia.
fatty h. 1. fatty degeneration of the myocardium; 2. accumulation of adipose tissue on the external surface of the h. with occasional infiltration of fat between the muscle bundles of the h. wall. SYN: cor adiposum.
frosted h. hyaloserositis involving the pericardium. SYN: icing h..
globular h. SYN: round h..
hairy h. SYN: fibrinous pericarditis.
Holmes h. a variant of double inlet left ventricle where the ventricular-arterial connection is concordant and the right ventricle is rudimentary.
horizontal h. description of the hearts electrical position; recognized in the electrocardiogram when the QRS in lead aVL resembles that in V₆ and QRS in aVF resembles that in V₁; also, loosely, when the electrical axis lies between −30° and +30°.
hyperthyroid h. response of the h. to hyperthyroidism, essentially the result of sympathetic stimulation producing rapid h. rates and ultimately cardiac failure and atrial fibrillation if untreated.
hypoplastic h. a small h., as seen in Addison disease.
icing h. SYN: frosted h..
intermediate h. loosely, description of the hearts electrical axis when this is directed at approximately between +30° and +60°. For cardiac position, recognized in the electrocardiogram when the QRS complexes in both lead aVL and aVF resemble that in V₆.
Jarvik artificial h. a pneumatic artificial h..
left h. the left atrium and left ventricle.
mechanical h. term loosely applied to any mechanical circulatory assist device.
movable h. SYN: cor mobile.
myxedema h. the enlarged h. associated with untreated severe hypothyroidism, often accompanied by pericardial effusion; rare in modern medicine.
ox h. a very large h., due to chronic hypertension or, more often, to aortic valve disease, especially regurgitation. SYN: bucardia, cor bovinum.
parchment h. a congenital or acquired condition in which there is thinning of the right ventricular myocardium. See Uhl anomaly. SYN: right ventricular hypoplasia.
pendulous h. SYN: cor pendulum.
pulmonary h. the right atrium and ventricle, receiving the venous blood and propelling it to the lungs. SEE ALSO: cor pulmonale.
right h. the right atrium and right ventricle.
round h. abnormally smooth arcuate contours of the h. on imaging due either to disease of the ventricles or to a false cardiac appearance produced by excessive pericardial fluid. SYN: globular h..
sabot h. SYN: coeur en sabot.
semihorizontal h. loosely refers to the hearts electrical axis when this is directed at approximately 0°. As a cardiac electrical position, recognized in the electrocardiogram when the QRS complex in lead aVL resembles V₆ while that in aVF is small algebraically or absolutely.
semivertical h. loosely descriptive of the hearts electrical axis when this is directed at approximately +60°. As a cardiac electrical position, recognized in the electrocardiogram when the QRS complex in lead aVF resembles V₆ while that in aVL is small algebraically or absolutely.
stone h. SYN: ischemic contracture of the left ventricle.
systemic h. the left atrium and ventricle, receiving the aerated blood from the lungs and propelling it throughout the body.
three-chambered h. congenital abnormality in which there may be a single atrium with two ventricles or a single ventricle with two atria. Rudimentary parts of the atrial and ventricular septa may be present but are incompetent to prevent a virtual single chamber in either case.
tiger h. a fatty degenerated h. in which the fat is disposed in the form of broken stripes in the subendocardial myocardium.
tobacco h. cardiac irritability marked by irregular action, palpitation, and sometimes pain, believed to occur as a result of the heavy use of tobacco.
univentricular h. an anomaly in which all blood flows through one ventricle or in which the arterioventricular valves are committed to empty into only one chamber in the ventricular mass.
venous h. the right side, including both the atrium and ventricle, of the h..
vertical h. loosely descriptive of the hearts electrical axis when this is directed at approximately +90°. As a cardiac electrical position, recognized in the electrocardiogram when the QRS complex in lead aVL resembles V₁ while that in aVF resembles V₆.
wooden-shoe h. SYN: coeur en sabot.

heartbeat
heartbeat (hart′bet)

A single complete cycle of contraction and dilation of heart muscle.

heartburn
heartburn (hart′bern)

SYN: pyrosis.

heartworm
heartworm

SYN: Dirofilaria immitis.

heat
heat (q) (het)

1. A high temperature; the sensation produced by proximity to fire or an incandescent object, as opposed to cold. 2. The kinetic energy of atoms and molecules, as well as rotation and vibration. 3. SYN: estrus. 4. SYN: enthalpy. [A.S. haete]
atomic h. the amount of h. required to raise an atom from 0° to 1°C; approximately the same for all elements (about 25 kJ/g-atom).
h. of combustion the quantity of h. liberated per gram-molecular weight when a substance undergoes complete oxidation.
h. of compression h. produced when a gas is compressed.
conductive h. h. transmitted by direct contact, as by an electric pad or hot-water bottle.
convective h. h. conveyed by a warm medium, such as air or water, in motion from its source.
conversive h. h. produced in a body by the absorption of waves that are not in themselves hot, such as the sun's rays or infrared radiation.
h. of crystallization the quantity of h. liberated or absorbed per mol when a substance passes into the crystalline state.
h. of dissociation the h. (expressed in calories or joules) expended in the dissociation of 1 mol of a substance into specified products.
h. of evaporation the h. absorbed in the evaporation of water, sweat or other liquid; for water it amounts to 540 cal/g at 100°C. SYN: h. of vaporization.
h. of formation the h. (expressed in calories or joules) absorbed or liberated during the (hypothetical) reaction in which a mole of a compound is formed from the necessary elements, in elemental form.
initial h. the first burst of h. produced after the beginning of a muscle twitch, described by A. V. Hill.
latent h. the amount of h. that a substance may absorb without an increase in temperature, as in conversion from solid to liquid state (ice to water at 0°C), or from liquid to gaseous state (water to steam at 100°C). Cf.:sensible h..
molecular h. the product of the specific h. of a body multiplied by its molecular weight.
prickly h. SYN: miliaria rubra.
radiant h. h. given off from any body in the form of infrared waves.
sensible h. the amount of h. that, when absorbed by a substance, causes a rise in temperature. Cf.:latent h..
h. of solution the quantity of h. absorbed or evolved when a solid is dissolved in a liquid.
specific h. the amount of h. required to raise any substance through 1°C of temperature, compared with that raising the same volume of water 1°C.
h. of vaporization SYN: h. of evaporation.

heat-labile
heat-labile (het′la′bl)

Destroyed or altered by heat.

heat-stable
heat-stable (het′sta′bl)

SYN: thermostabile.

heatstroke
heatstroke (het′strok)

A severe and often fatal illness produced by exposure to excessively high temperatures, especially when accompanied by marked exertion; characterized by headache, vertigo, confusion, hot dry skin, and a slight rise in body temperature; in severe cases, very high fever, vascular collapse, and coma develop. SYN: heat apoplexy (1) , heat hyperpyrexia, malignant hyperpyrexia, thermic fever.

Hebeloma
Hebeloma (heb-e-lo′ma)

A genus of mushrooms that is a source of gastrointestinal toxins.

hebephrenia
hebephrenia (he-be-fre′ne-a, heb′e-)

A syndrome characterized by shallow and inappropriate affect, giggling, and silly, regressive behavior and mannerisms; a subtype of schizophrenia now renamed disorganized schizophrenia. [G. hebe, puberty, + phren, the mind]

hebephrenic
hebephrenic (he-be-fren′ik, heb-e-)

Relating to or characterized by hebephrenia.

Heberden
Heberden

William, English physician, 1710–1801. See H. angina, H. nodes, under node, Rougnon-H. disease.

hebetic
hebetic (he-bet′ik)

Pertaining to youth. [G. hebetikos, youthful, fr. hebe, youth]

hebetude
hebetude (heb′e-tood)

SYN: moria (1) . [L. hebetudo, fr. hebeo, to be dull]

hebiatrics
hebiatrics (he-be-at′riks)

SYN: adolescent medicine. [G. hebe, youth, + iatrikos, relating to medicine]

Hebra
Hebra

Ferdinand von, Austrian dermatologist, 1816–1880. See H. prurigo.

hecateromeric
hecateromeric (hek′a-ter-o-mer′ik)

Denoting a spinal neuron whose axon divides and gives off processes to both sides of the cord; usually the same as a heteromeric neuron. SYN: hecatomeral, hecatomeric. [G. hekateros, each of two, + meros, part]

hecatomeral
hecatomeral, hecatomeric (hek′a-tom′er-al, hek′a-to-mer′ik)

SYN: hecateromeric.

Hecht
Hecht

Victor, early 20th century Austrian pathologist. See H. pneumonia.

Heck
Heck

John W., U.S. dentist, *1923. See H. disease.

hectic
hectic (hek′tik)

Denoting a daily afternoon rise of temperature, accompanied by a flush on the cheeks, occurring in active tuberculosis and other infections; use of the term is based on the appearance of the temperature chart. [G. hektikos, habitual, h., consumptive, fr. hexis, habit]

hecto- hecto- (h)

Prefix used in the SI and metric system to signify multiples of one hundred (10²). [G. hekaton, one hundred]

hectogram
hectogram (hek′to-gram)

One hundred grams, the equivalent of 1543.7 grains.

hectoliter
hectoliter (hek′to-le-ter)

One hundred liters, the equivalent of 105.7 quarts or 26.4 American (22 imperial) gallons.

hedeoma
hedeoma (he-de-o′ma)

See pennyroyal.

hederiform
hederiform (hed′er-i-form)

Ivy-shaped; a term used for certain sensory endings in the skin. [L. hedera, ivy, + forma, shape]

hedonophobia
hedonophobia (he′do-no-fo′be-a)

Morbid fear of pleasure. [G. hedone, delight, + phobos, fear]

Hedström
Hedström

Gustav, Swedish endodontist. See H. file.

heel
heel (hel) [TA]

1. Proximal portion of the plantar surface of the foot. 2. SYN: calx (2) . 3. SYN: distal end. [A.S. hela]
black h. SYN: calcaneal petechiae.
cracked h. SYN: keratoderma plantare sulcatum.
painful h. a condition in which bearing weight on the h. causes pain of varying severity. SYN: calcaneodynia.
prominent h. a condition marked by a tender swelling on the os calcis due to a thickening of the periosteum or fibrous tissue covering the back of the os calcis.

Heerfordt
Heerfordt

Christian Frederick, Danish ophthalmologist, *1871. See H. disease.

Hegar
Hegar

Alfred, German gynecologist, 1830–1914. See H. dilators, under dilator, H. sign.

Hegglin
Hegglin

Robert M.P., Swiss physician, 1907–1970. See H. anomaly, H. syndrome, May-H. anomaly.

Hehner
Hehner

Otto, British chemist, 1853–1924. See H. number.

Heidenhain
Heidenhain

Rudolph P.H., German histologist and physiologist, 1834–1897. See H. crescents, under crescent, H. demilunes, under demilune, H. law, H. azan stain, H. iron hematoxylin stain, H. pouch, Biondi-H. stain.

height
height (h) (hit)

Vertical measurement.
anterior facial h. (AFH) in cephalometrics, the linear measurement from the nasion to the menton.
h. of contour the line encircling a tooth or other structure at its greatest bulge or diameter. It relates to a selected path of insertion of a dental appliance or device.
cusp h. 1. the shortest distance between the tip of a cusp and its base plane; 2. the shortest distance between the deepest part of the central fossa of a posterior tooth and a line connecting the points of the cusps of the tooth.
facial h. the linear dimension in the midline from the hairline to the menton.
nasal h. the distance between the nasion and the lower border of the nasal aperture.
orbital h. the distance between the midpoints of the upper and lower margins of the orbit.

Heilbronner
Heilbronner

Karl, Dutch physician, 1869–1914. See H. thigh.

Heim
Heim

Ernst L., German physician, 1747–1834. See H.-Kreysig sign.

Heimlich
Heimlich

Henry J., U.S. thoracic surgeon, *1920. See H. maneuver.

Heine
Heine

Leopold, German ophthalmologist, 1870–1940.

Heineke
Heineke

Walter, German surgeon, 1834–1901. See H.-Mikulicz pyloroplasty.

Heinz
Heinz

Robert, German pathologist, 1865–1924. See H. body anemia, H. bodies, under body, H. body test, H.-Ehrlich body, H. body anemia.

Heister
Heister

Lorenz, German anatomist, 1683–1758. See H. diverticulum, H. valve.

HeLa
HeLa (he′la)

Referring to cells of the first continuously cultured (human cervical) carcinoma strain. [Henrietta Lacks (d. 1951), whose cervical carcinoma was the source of the cell line]

helcomenia
helcomenia (hel-ko-me′ne-a)

Occurrence of ulcers at the time of a menstruation. [G. helkos, ulcer, + emmenos, monthly]

Held
Held

Hans, German anatomist, 1866–1942. See H. bundle, H. decussation.

helianthine
helianthine (he-li-an′thin)

SYN: methyl orange.

helical
helical (hel′i-kal)

1. Relating to a helix. SYN: helicine (2) . 2. SYN: helicoid. [G. helix, a coil]

helices
helices (hel′i-sez)

Plural of helix.

helicine
helicine (hel′i-sen)

1. Coiled. 2. SYN: helical (1) . [G. helix, a coil]

Helicobacter
Helicobacter (hel′i-ko-bak′ter)

A genus of helical, curved, or straight microaerophilic bacteria with rounded ends and multiple sheathed flagella (unipolar or bipolar and lateral) with terminal bulbs. Form nonpigmented, translucent colonies, 1–2 mm in diameter. Catalase and oxidase positive. Found in gastric mucosa of primates, including human beings and ferrets. Some species are associated with gastric and peptic ulcers and predispose to gastric carcinoma. The type species is H. pylori.
H. cinaedi a bacterial species associated with cases of proctitis and colitis in homosexual men.
H. fennelliae a bacterial species reported associated with proctitis and colitis in homosexual men.
H. heilmannii species observed in gastric mucosa. This agent has a low prevalence (less than 1% in patients), has not been cultured in vitro, and is of unknown pathogenic significance.
H. pylori a bacterial species that produces urease and causes gastritis and is involved in most cases of peptic ulcer disease of the stomach and duodenum; infection with this organism also plays an etiologic role (probably along with dietary cofactors) in dysplasia and metaplasia of gastric mucosa, distal gastric adenocarcinoma, and non-Hodgkin lymphoma of the stomach. SYN: Campylobacter pylori.The organism was first observed in 1982 by Robin Warren and Barry J. Marshall at Royal Perth Hospital in Western Australia in biopsy specimens from patients with chronic gastritis. Originally believed to be a species of Campylobacter, the organism was reclassified as H. pylori in 1989. H. pylori, a curved or spiral, flagellated Gram-negative bacillus, colonizes the gastric mucosa, attaching itself to the surface of mucus-secreting columnar cells. The ability of the organism to survive in an acid medium is due to its production of urease, which converts urea to ammonia and alkalizes the film of mucus in which it resides. Infection with H. pylori is common worldwide, and the incidence of infection increases with age, reaching about 50% among persons aged 60. Transmission is believed to be from person to person by the fecal-oral route. Familial clustering of infection and a higher incidence among blacks and Hispanics have been attributed to social rather than genetic factors. Once infection occurs, it typically remains for life unless treated with antibiotics. Newly acquired infection results in extensive damage to parietal cells, with acute gastritis accompanied by impairment of acid production, which may be transitory. Most people infected have no symptoms (possibly because some strains of H. pylori do not produce cytotoxins) but about 1% of H. pylori–infected adults each year develop peptic ulcer. The risk of progression to peptic ulcer disease is increased by cigarette smoking and long-term use of nonsteroidal antiinflammatory agents. About 70% of all people with gastric ulcers and 90% of those with duodenal ulcers are found to be infected with H. pylori. In the U.S., about 500,000 new cases of peptic ulcer disease occur each year. The disease is responsible for 3–4 million physician visits and approximately 16,000 deaths annually. H. pylori infection has not been associated with nonulcer dyspepsia or inflammatory disorders of the digestive tract other than peptic ulceration. However, the incidence of both gastric adenocarcinoma and gastric lymphoma is higher in infected persons. In addition, the organism has been implicated in some cases of cholecystitis and autoimmune thyroiditis, and some studies have suggested that gastric infection with H. pylori may be a factor, by an unknown mechanism, in some cases of sudden infant death syndrome (SIDS). Diagnosis of H. pylori infection can be confirmed by identification of the organism in stained sections of gastric biopsy material, by culture from biopsy material, by testing biopsy material for urease activity, by identification of bacterial antigen in stool, by finding IgG antibody to the organism in the serum (the method of choice to confirm infection in a previously untreated patient), or by detection of urease activity with various biochemical tests. The urea breath test is more useful than serologic testing to confirm eradication of H. pylori after a course of treatment, since IgG antibody may remain elevated for more than 1 year after eradication. Eradication of the organism with antibiotic therapy does not yield faster healing of a peptic ulcer than treatment with antisecretory agents, but it greatly reduces the likelihood of ulcer recurrence. Recommended regimens for eradication of H. pylori include combinations of bismuth subsalicylate with 2 antibiotics (metronidazole or clarithomycin and tetracycline or amoxicillin). Acquired resistance of H. pylori to the macrolide and imidazole antibiotics is a growing problem. It is estimated that about 30% of strains of the organism in the U.S. are resistant to metronidazole and that almost 10% are resistant to macrolides. A major factor in the emergence of resistant strains appears to be an inadequate or failed first course of treatment. Active vaccination by oral administration of an enzymatically inactive recombinant subunit of H. pylori urease combined with a mucosal adjuvant (labile toxin of Escherichia coli) has elicited microbiologic and clinical cure of H. pylori infection in animal studies and limited human trials.

helicoid
helicoid (hel′i-koyd)

Resembling a helix. SYN: helical (2) . [G. helix, a coil, + eidos, resemblance]

helicopodia
helicopodia (hel′i-ko-po′de-a)

SYN: helicopod gait. [G. helix, a coil, + pous, foot]

helicotrema
helicotrema (hel′i-ko-tre′ma) [TA]

A semilunar opening at the apex of the cochlea through which the scala vestibuli and the scala tympani of the cochlea communicate with one another. SYN: Breschet hiatus, Scarpa hiatus. [G. helix, a spiral, + trema, a hole]

Helie
Helie

Louis T., French gynecologist, 1804–1867. See H. bundle.

heliencephalitis
heliencephalitis (he-le-en-sef-a-li′tis)

Inflammation of the brain following sunstroke. [G. helios, sun, + enkephalos, brain, + -itis, inflammation]

helio- helio-

The sun. [G. helios]

helioaerotherapy
helioaerotherapy (he′le-o-ar-o-thar′a-pe)

Treatment of disease by exposure to sunshine and fresh air.

heliopathy
heliopathy (he-le-op′a-the)

Injury from exposure to sunlight. [helio- + G. pathos, suffering]

heliophobia
heliophobia (he′le-o-fo′be-a)

Morbid fear of exposure to the sun's rays. [helio- + G. phobos, fear]

heliosis
heliosis (he-le-o′sis)

SYN: sunstroke. [helio- + G. -osis, condition]

heliotaxis
heliotaxis (he-le-o-tak′sis)

A form of phototaxis, and perhaps of thermotaxis, in which there is a tendency to growth or movement toward (positive h.) or away from (negative h.) the sun or the sunlight. SYN: heliotropism. [helio- + G. taxis, orderly arrangement]

heliotropism
heliotropism (he-le-ot′ro-pizm)

SYN: heliotaxis. [helio- + G. trope, a turning]

Heliozoea
Heliozoea (he′le-o-zo′e-a)

A class of protozoans (subphylum Sarcodina) distinguished by stiff radiating axopodia on all sides, usually naked, though some have a skeleton of siliceous scales and spines, but without a central capsule. They are mostly fresh water dwellers, and colonial forms are common. [helio- + G. zoon, animal]

helium
helium (He) (he′le-um)

A gaseous element present in minute amounts in the atmosphere (0.000524% of dry volume); atomic no. 2, atomic wt. 4.002602; used as a diluent of medicinal gases; used as a diluent of oxygen principally in nonmedical applications, and in its liquid form as the coolant for super-conducting magnets (as in magnetic resonance imaging). [G. helios, the sun]

helium-3
helium-3

The rare stable isotope of helium (1.37 parts per million of ordinary helium); produced by the beta decay of tritium.

helium-4
helium-4

The common helium isotope, making up 99.999% of natural helium; it is emitted in the form of alpha rays (which are helium nuclei), from a variety of radionuclides.

helix
helix, pl .helices (he′liks, hel′i-sez) [TA]

1. [NA] The margin of the auricle; a folded rim of cartilage forming the upper part of the anterior, the superior, and the greater part of the posterior edges of the auricle. 2. A line in the shape of a coil (or a spring, or the threads on a bolt), each point being equidistant from a straight line that is the axis of the cylinder in which each point of the h. lies; often, mistakenly, applied to a spiral. [L. fr. G. h., a coil]
3₁₀ h. a type of right-handed h. found in small pieces in a number of proteins; has three amino acid residues per turn.
3.6₁₃ h. SYN: α h..
α h. the helical (commonly right-handed) form present in many proteins, deduced by Pauling and Corey from x-ray diffraction studies of proteins such as α-keratin; the h. is stabilized by hydrogen bonds between, e.g., R₂C&dbond;O and HNR₂′ groups (symbolized by the center dot in R₂CO&chmpnt;HNR₂′) of different eupeptide bonds. In a true α h., there are 3.6 amino acid residues per turn of the h. and a rise of 1.5 Å per residue. SYN: 3.6₁₃ h., Pauling-Corey h..
collagen h. an extended left-handed h. resulting from the high levels of glycine, l-proline, and l-hydroxyproline present in the collagens. There are 3.3 amino acids per turn of the h.. Three of those left-handed helices form a triple superhelix that is right-handed.
DNA h. SYN: Watson-Crick h..
double h. SYN: Watson-Crick h..
π h. a rare right-handed h. found only in small portions of certain proteins. Stabilized by similar hydrogen bonds as in an α h.; there are 4.3 amino acid residues per turn of this h..
Pauling-Corey h. SYN: α h..
triple h. the superhelix formed (right-handed) from three individual collagen helices (each being left-handed).
twin h. SYN: Watson-Crick h..
Watson-Crick h. the helical structure assumed by two strands of deoxyribonucleic acid, held together throughout their length by hydrogen bonds between bases on opposite strands, referred to as Watson-Crick base pairing. See base pair. SYN: DNA h., double h., twin h..

hellebore
hellebore (hel′e-bor)

A plant of the genus Helleborus, especially H. niger (black h.). SEE ALSO: Veratrum album, Veratrum viride. [G. helleboros]
false h. SYN: adonis.

helleborin
helleborin (he-leb′o-rin, hel-e-bo′rin)

A toxic glycoside from Veratrum viride (green hellebore); a narcotic.

helleborism
helleborism (hel′e-bor-izm)

A condition resulting from poisoning by Veratrum Helleborus.

helleborus
helleborus (he-leb′o-rus)

Black hellebore, the dried rhizome and roots of H. niger (family Ranunculaceae); used as a cardiac and arterial tonic, diuretic, and cathartic. [G. helleboros]

Heller
Heller

Arnold L.G., German pathologist, 1840–1913. See H. plexus.

Heller
Heller

Ernst, German surgeon, 1877–1964. See H. operation.

Hellin
Hellin

Dyonizy (Dionys), Polish pathologist, 1867–1935. See H. law.

Helly
Helly

Konrad, Swiss pathologist, *1875. See H. fixative.

Helmholtz
Helmholtz

Hermann L.F. von, German physician, physicist, and physiologist, 1821–1894. See H. axis ligament, H. energy, H. theory of accommodation, H. theory of color vision, H. theory of hearing, H.-Gibbs theory, Gibbs-H. equation, Young-H. theory of color vision.

helminth
helminth (hel′minth)

An intestinal vermiform parasite, primarily nematodes, cestodes, trematodes, and acanthocephalans. [G. helmins, worm]

helminthagogue
helminthagogue (hel-minth′a-gog)

SYN: anthelmintic (1) . [G. helmins, worm, + agogos, leading]

helminthemesis
helminthemesis (hel-min-them′e-sis)

The vomiting or expulsion through the mouth of intestinal worms. [G. helmins, a worm, + emesis, vomiting]

helminthiasis
helminthiasis (hel-min-thi′a-sis)

The condition of having intestinal vermiform parasites. SYN: helminthism, invermination.

helminthic
helminthic (hel-min′thik)

1. Helmintic. 2. SYN: anthelmintic (1) .

helminthism
helminthism (hel′min-thizm)

SYN: helminthiasis.

helminthoid
helminthoid (hel-min′thoyd)

Wormlike. [G. helminthodes, wormlike, fr. helmins, worm, + eidos, resemblance]

helminthology
helminthology (hel-min-thol′o-je)

The branch of science concerned with worms; especially the branch of zoology and of medicine concerned with intestinal vermiform parasites. SYN: scolecology. [G. helmins, worm, + logos, study]

helminthoma
helminthoma (hel-min-tho′ma)

A discrete nodule of granulomatous inflammation (including the healed stage) caused by a helminth or its products, so termed on the basis of certain gross resemblances to a neoplasm. [G. helmins, worm, + -oma, tumor]

helminthophobia
helminthophobia (hel′min-tho-fo′be-a)

Morbid fear of worms. [G. helmins, worm, + phobos, fear]

Helminthosporium
Helminthosporium (hel-min-tho-spor′e-um)

A saprobic fungus that is usually isolated in clinical laboratories; it has determinant parallel-walled conidiophores; commonly misapplied to isolates of Drechslera.

helmintic
helmintic (hel-min′tik)

1. Relating to or infected with parasitic worms. 2. SYN: anthelmintic (1) .

Heloderma
Heloderma (he-lo-der′ma)

The only genus of poisonous lizards, such as the Gila monster, so named because of the tubercular scales which cover their bodies. They are native to Mexico and the southwestern U.S. [G. helos, nail, + derma, skin]

Helvella esculenta
Helvella esculenta (hel-vel′a es-ku-len′ta)

SYN: Gyromitra esculenta.

Helweg
Helweg

Hans K.S., Danish physician, 1847–1901. See H. bundle.

Helweg-Larssen
Helweg-Larssen

H., Hans F., 20th century Danish dermatologist. See Helweg-Larssen syndrome.

hem- hem-, hema-

Blood. SEE ALSO: hemat-, hemato-, hemo-. [G. haima]

hemachrome
hemachrome (he′ma-krom, hem′a-)

The coloring matter of the blood, hemoglobin or hematin. [hema- + G. chroma, color]

hemacytometer
hemacytometer (he′ma-si-tom′e-ter, hem′a-)

SYN: hemocytometer.

hemacytozoon
hemacytozoon (he′ma-si-to-zo′on, hem′a)

SYN: hemocytozoon.

hemadostenosis
hemadostenosis (he′ma-do-ste-no′sis, hem′ad-o)

Contraction of the arteries. [G. haimas (haimad-), a stream of blood, + stenosis, a narrowing]

hemadsorption
hemadsorption (he′mad-sorp-shun, hem′ad-)

A phenomenon manifested by an agent or substance adhering to or being adsorbed on the surface of a red blood cell.

hemafacient
hemafacient (he-ma-fa′she-ent, hem-a-)

SYN: hemopoietic.

hemagglutination
hemagglutination (he-ma-gloo′ti-na′shun)

The agglutination of red blood cells; may be immune as a result of specific antibody either for red blood cell antigens per se or other antigens which coat the red blood cells, or may be nonimmune as in h. caused by viruses or other microbes. SYN: hemoagglutination.
passive h. a kind of passive agglutination in which erythrocytes, usually modified by mild treatment with tannic acid or other chemicals, are used to adsorb soluble antigen onto their surface, and which then agglutinate in the presence of antiserum specific for the adsorbed antigen. SYN: indirect h. test.
reverse passive h. a diagnostic technique for virus infection using agglutination by viruses of red blood cells that previously have been coated with antibody specific to the virus.
viral h. the nonimmune agglutination of suspended red blood cells by certain of a wide range of otherwise unrelated viruses, usually by the virion itself but in some instances by products of viral growth ( e.g., subunits), the species of erythrocyte agglutinated differing with the different viruses. SEE ALSO: h. inhibition.

hemagglutinin
hemagglutinin (he′ma-gloo′ti-nin, hem-)

A substance, antibody or other, that causes hemagglutination. SYN: hemoagglutinin.

hemagogic
hemagogic (he-ma-goj′ik, hem-a-)

Promoting a flow of blood.

hemal
hemal (he′mal)

1. Relating to the blood or blood vessels. 2. Referring to the ventral side of the vertebral bodies or their precursors, where the heart and great vessels are located, as opposed to neural (2). [G. haima, blood]

hemalum
hemalum (he-mal′um, hem-)

A solution of hematoxylin and alum used as a nuclear stain in histology, especially with eosin as a counterstain.

hemamebiasis
hemamebiasis (he′ma-me-bi′a-sis, hem′a-)

Any infection with ameboid forms of parasites in red blood cells, as in malaria.

hemanalysis
hemanalysis (he-ma-nal′i-sis, hem-)

Analysis of the blood; an examination of blood, especially with reference to chemical methods. [G. haima, blood, + analysis]

hemangiectasis
hemangiectasis, hemangiectasia (he-man-je-ek′tasis, hem-an-; -ek-ta′ze-a)

Dilation of blood vessels. [G. haima, blood, + angeion, vessel, + ektasis, a stretching]

hemangio- hemangio-

The blood vessels. [G. haima, blood, + angeion, vessel]

hemangioblast
hemangioblast (he-man′je-o-blast)

A primitive embryonic cell of mesodermal origin producing cells from which are derived vascular endothelium, reticuloendothelial elements, and blood-forming cells of all types. [hemangio- + G. blastos, germ]

hemangioblastoma
hemangioblastoma (he-man′je-o-blas-to′ma)

A benign neoplasm frequently arising in the cerebellum composed of capillary vessel–forming endothelial cells and stromal cells; a slowly growing tumor that affects, primarily, middle-aged individuals; increased incidence in von Hippel-Lindau disease. SYN: angioblastoma, Lindau tumor.

hemangioendothelioblastoma
hemangioendothelioblastoma (he-man′je-o-en-do-the′-le-o-blasto′ma)

Hemangioendothelioma in which the endothelial cells seem to be especially immature forms. [hemangio- + endothelium + G. blastos, germ, + -oma, tumor]

hemangioendothelioma
hemangioendothelioma (he-man′je-o-en-do-the-le-o′ma)

A neoplasm derived from blood vessels, characterized by numerous prominent endothelial cells that occur singly, in aggregates, and as the lining of congeries of vascular tubes or channels; in the elderly, may be malignant (angiosarcoma or hemangiosarcoma), but in children are benign and probably represent a growing stage of capillary hemangioma. [hemangio- + endothelium + G. -oma, tumor]
h. tuberosum multiplex an eruption of pinkish papules, caused by hyperplasia of the endothelium of the superficial blood vessels.

hemangiofibroma
hemangiofibroma (he-man′je-o-fi-bro′ma)

A hemangioma with an abundant fibrous tissue framework.
juvenile h. SYN: juvenile angiofibroma.

hemangioma
hemangioma (he-man′je-o′ma)

A congenital anomaly, in which proliferation of blood vessels leads to a mass that resembles a neoplasm; it can occur anywhere in the body but is most frequently noticed in the skin and subcutaneous tissues; most hemangiomas undergo spontaneouos regression. SEE ALSO: nevus. [hemangio- + G. -oma, tumor]
capillary h. an overgrowth of capillary blood vessels, seen most commonly in the skin, at or soon after birth, as a soft bright red to purple nodule or plaque that usually disappears by the fifth year. The most common type of h.. SYN: capillary angioma, capillary h. of infancy, nevus vascularis, nevus vasculosus, superficial angioma.
capillary h. of infancy SYN: capillary h..
cavernous h. old term for deep cutaneous h. that manifests spontaneous involution. Also used incorrectly for venous malformation.
lobular capillary h. SYN: pyogenic granuloma.
racemose h. SYN: cirsoid aneurysm.
sclerosing h. 1. a benign lung or bronchial lesion, often subpleural, sometimes multiple, which forms hyalinized connective tissue. 2. SYN: dermatofibroma.
senile h. red papules caused by weakening of dermal capillary walls, that do not blanch on pressure, seen mostly in persons over 30 years of age. SYN: cherry angioma, De Morgan spots.
spider h. SYN: spider angioma.
strawberry h. hyperproliferation of immature capillary vessels, usually on the head and neck, present at birth or within the first 2–3 months postnatally, which commonly regresses without scar formation.
verrucous h. incorrect term for cutaneous vascular malformation comprised of abnormal capillaries and lymphatics.

hemangiomatosis
hemangiomatosis (he-man′je-o-ma-to′sis)

A condition in which there are numerous hemangiomas.

hemangiopericytoma
hemangiopericytoma (he-man′je-o-per′i-si-to′ma)

An uncommon vascular, usually benign, neoplasm composed of round and spindle cells that are derived from the pericytes and surround endothelium-lined vessels; malignant hemangiopericytomas are difficult to distinguish microscopically from the benign. [hemangio- + pericyte + G. -oma, tumor]

hemangiosarcoma
hemangiosarcoma (he-man′je-o-sar-ko′ma)

A rare malignant neoplasm characterized by rapidly proliferating, extensively infiltrating, anaplastic cells derived from blood vessels and lining irregular blood-filled or lumpy spaces.

hemapheic
hemapheic (he-ma-fe′ik, hem-a-)

Pertaining to or containing hemaphein.

hemaphein
hemaphein (he-ma-fe′in, hem-a-)

A brown pathologic pigment derived from hemoglobin; said to be a combination of indican and urobilin. [G. haima, blood, + phaios, dusky]

hemapheism
hemapheism (he-ma-fe′izm, hem-a-)

The presence of hemaphein in the blood plasma and urine.

hemarthrosis
hemarthrosis (he′mar-thro′sis, hem′ar-)

Blood in a joint. [G. haima, blood, + arthron, joint]

hemastrontium
hemastrontium (he-ma-stron′she-um, hem-a-)

A stain made by adding strontium chloride to a solution of hematein and aluminum chloride in citric acid and alcohol; used in histology.

hemat- hemat-

Blood. SEE ALSO: hem-, hemato-, hemo-. [G. haima (haimat-)]

hematachometer
hematachometer (he′ma-ta-kom′e-ter, hem′a-)

SYN: hemotachometer.

hematapostema
hematapostema (he′mat-a-pos-te′ma, hem′at-)

An abscess into which blood has effused. [hemat- + G. apostema, abscess]

hematein
hematein (he-ma-te′in, hem-a)

An oxidation product of hematoxylin.
Baker acid h. an acidic solution of oxidized hematoxylin used on frozen sections for staining phospholipids.

hematemesis
hematemesis (he-ma-tem′e-sis, hem-a-)

Vomiting of blood. SYN: vomitus cruentes. [hemat- + G. emesis, vomiting]

hematencephalon
hematencephalon (he′mat-en-sef′a-lon, hem′at-)

SYN: cerebral hemorrhage. [hemat- + G. enkephalos, brain]

hematherapy
hematherapy (he′ma-thar′a-pe, hem′a-)

SYN: hemotherapy.

hematherm
hematherm (he′ma-therm, hem′a-)

SYN: homeotherm. [G. haima, blood, + thermos, warm]

hemathermal
hemathermal (he-ma-ther′mal, hem-a-)

SYN: homeothermic. [G. haima, blood, + thermos, warm]

hemathermous
hemathermous (he-ma-ther′mus, hem-a-)

SYN: homeothermic.

hemathorax
hemathorax (he-ma-thor′aks, hem-a-)

SYN: hemothorax.

hematic
hematic (he-mat′ik)

1. Relating to blood. SYN: hemic. 2. SYN: hematinic (2) .

hematid
hematid (he′ma-tid, hem′a-)

1. Obsolete term for a red blood cell. 2. Obsolete term for a cutaneous eruption presumed to be caused by a substance in the circulating blood. [hemat- + -id]

hematidrosis
hematidrosis (he′mat-i-dro′sis, hem′at-)

Excretion of blood or blood pigment in the sweat; an extremely rare disorder. [hemat- + G. hidros, sweat]

hematimeter
hematimeter (he-ma-tim′e-ter, hem-a-)

SYN: hemocytometer.

hematin
hematin (he′ma-tin, hem′a-)

Heme in which the iron is Fe(III) (Fe³⁺); the prosthetic group of methemoglobin. SYN: ferriheme, hematosin, hydroxyhemin, oxyheme, oxyhemochromogen, phenodin.
h. chloride SYN: hemin.
reduced h. SYN: heme.

hematinemia
hematinemia (he′ma-ti-ne′me-a, hem′a-)

The presence of heme in the circulating blood. [hematin + G. haima, blood]

hematinic
hematinic (he-ma-tin′ik, hem-a-)

1. Improving the condition of the blood. 2. An agent that improves the quality of blood by increasing the number of erythrocytes and/or the hemoglobin concentration. SYN: hematic (2) . SYN: hematonic.

hemato- hemato-

Combining form denoting blood. SEE ALSO: hem-, hemat-, hemo-. [G. haima (haimat-)]

hematobilia
hematobilia (he′ma-to-bil′e-a, hem′a-)

SYN: hemobilia.

hematobium
hematobium (he-ma-to′be-um, hem-a-)

Any microorganism that is parasitic in the blood, especially an animal form or hemozoon. [hemato- + G. bios, life]

hematoblast
hematoblast (he′ma-to-blast, hem′a-)

A primitive, undifferentiated form of blood cell from which erythroblasts, lymphoblasts, myeloblasts, and other immature blood cells are derived; probably identical or closely similar to hemocytoblast and hemohistioblast; in normal bone marrow, present only in small numbers and difficult to identify in smears, inasmuch as hematoblasts are fragile and easily disintegrated; when marrow is hyperplastic, they may be observed in small groups. [hemato- + G. blastos, germ]
Hayem h. obsolete term for platelet.

hematocele
hematocele (he′ma-to-sel, hem′a-)

1. SYN: hemorrhagic cyst. 2. Effusion of blood into a canal or a cavity of the body. 3. Swelling due to effusion of blood into the tunica vaginalis testis. [hemato- + G. kele, tumor]
pelvic h. intraperitoneal effusion of blood into the pelvis.
pudendal h. effusion of blood into the labium majus.

hematocephaly
hematocephaly (he′ma-to-sef′a-le, hem′a-)

Intracranial effusion of blood, commonly in a fetus. [hemato- + G. kephale, head]

hematochezia
hematochezia (he′ma-to-ke′ze-a, hem′a-)

Passage of bloody stools, in contradistinction to melena, or tarry stools. [hemato- + G. chezo, to go to stool]

hematochlorin
hematochlorin (he′ma-to-klo′rin, hem′a)

A green coloring matter derived from hemoglobin obtained from the placenta. [hemato- + G. chloros, light green + -in]

hematochyluria
hematochyluria (he′ma-to-ki-loo′re-a, hem′a-)

Presence of blood as well as chyle in the urine. [hemato- + G. chylos, juice, + ouron, urine]

hematocolpometra
hematocolpometra (he′ma-to-kol′po-me′tra)

Accumulation of blood in the uterus and vagina resulting from an imperforate hymen or other lower vaginal obstruction. [hemato- + G. kolpos, vagina, + metra, womb]

hematocolpos
hematocolpos (he′ma-to-kol′pos, hem′a-)

An accumulation of menstrual blood in the vagina in consequence of imperforate hymen or other obstruction. SYN: retained menstruation. [hemato- + G. kolpos, vagina]

hematocrit
hematocrit (Hct) (he′ma-to-krit, hem′a-)

1. Percentage of the volume of a blood sample occupied by cells. Cf.:plasmacrit. 2. Obsolete term for a centrifuge or device for separating the cells and other particulate elements of the blood from the plasma. [hemato- + G. krino, to separate]

hematocryal
hematocryal (he-ma-tok′re-al, hem-a-)

SYN: poikilothermic. [hemato- + G. kryos, cold]

hematocyst
hematocyst (he′ma-to-sist, hem′a-)

SYN: hemorrhagic cyst.

hematocystis
hematocystis (he′ma-to-sis′tis, hem′a-)

Presence of blood in the bladder. [hemato- + G. kystis, bladder]

hematocyte
hematocyte (he′ma-to-sit, hem′a-)

SYN: hemocyte.

hematocytoblast
hematocytoblast (he′ma-to-si′to-blast, hem′a-)

SYN: hemocytoblast.

hematocytolysis
hematocytolysis (he′ma-to-si-tol′e-sis, hem′a-)

SYN: hemocytolysis.

hematocytometer
hematocytometer (he′ma-to-si-tom′e-ter, hem′a-)

SYN: hemocytometer.

hematocytozoon
hematocytozoon (he′ma-to-si′to-zo′on, hem′a-)

SYN: hemocytozoon.

hematodyscrasia
hematodyscrasia (he′ma-to-dis-kra′ze-a, hem′a-)

SYN: hemodyscrasia.

hematodystrophy
hematodystrophy (he′ma-to-dis′tro-fe, hem′a-)

SYN: hemodystrophy.

hematogenesis
hematogenesis (he′ma-to-jen′e-sis, hem′a-)

SYN: hemopoiesis. [hemato- + G. genesis, production]

hematogenic
hematogenic, hematogenous (he′ma-to-jen′ik, hem′a-; hem-a-toj′en-us)

1. SYN: hemopoietic. 2. Pertaining to anything produced from, derived from, or transported by the blood.

hematohistioblast
hematohistioblast (he′ma-to-his′te-o-blast, hem′a-)

SYN: hemohistioblast.

hematohiston
hematohiston (he′ma-to-his′ton, hem′a-)

SYN: globin.

hematoidin
hematoidin (he-ma-toy′din)

A pigment derived from hemoglobin that contains no iron but is closely related to or identical to bilirubin. H. is formed intracellularly, presumably within reticuloendothelial cells, but is often found extracellularly after 5–7 days in foci of previous hemorrhage. It occurs as refractile, yellow-brown and orange-red granules, but more characteristically as rhomboid plates arranged in a radial pattern, so-called h. burrs. SYN: blood crystals, h. crystals. [hemato- + G. eidos, resemblance, + -in]

hematologist
hematologist (he-ma-tol′o-jist, hem-a-)

A physician trained and experienced in hematology, i.e., skilled in performing diagnostic examinations of blood and bone marrow, or in treatment of such diseases, or both.

hematology
hematology (he-ma-tol′o-je, hem-a-)

The medical specialty that pertains to the anatomy, physiology, pathology, symptomatology, and therapeutics related to the blood and blood-forming tissues. SYN: hemology. [hemato- + G. logos, study]

hematolymphangioma
hematolymphangioma (he′ma-to-limf′an-je-o′-ma)

A congenital anomaly consisting of numerous, closely packed, variably sized lymphatic vessels and larger channels, in association with a moderate number of blood vessels of a similar type.

hematolysis
hematolysis (he-ma-tol′i-sis, hem-a-)

SYN: hemolysis.

hematolytic
hematolytic (he′ma-to-lit′ik, hem′a)

SYN: hemolytic.

hematoma
hematoma (he-ma-to′ma, hem-a-)

A localized mass of extravasated blood that is relatively or completely confined within an organ or tissue, a space, or a potential space; the blood is usually clotted (or partly clotted), and, depending on how long it has been there, may manifest various degrees of organization and decolorization. [hemato- + G. -oma, tumor]
communicating h. SYN: pseudoaneurysm.
corpus luteum h. SYN: corpus hemorrhagicum.
epidural h. SYN: extradural hemorrhage.
intracranial h. intracranial hemorrhage.
intramural h. a h. in the wall of a structure, such as the bowel or bladder, usually resulting from trauma or excessive anticoagulation.
pulsatile h. SYN: pseudoaneurysm.
subdural h. SYN: subdural hemorrhage.

hematometra
hematometra (he′ma-to-me′tra, hem′a-)

A collection or retention of blood in the uterine cavity. SYN: hemometra. [hemato- + G. metra, uterus]

hematometry
hematometry (he-ma-tom′e-tre, hem-a)

Examination of the blood in order to determine any or all of the following: 1) the total number, types, and relative proportions of various blood cells; 2) the number or proportion of other formed elements; 3) the percentage of hemoglobin. In some instances, h. is used to include a determination of blood pressure. SYN: hemometry. [hemato- + G. metron, measure]

hematomphalocele
hematomphalocele (he′mat-om-fal′o-sel, hem′at-)

Umbilical hernia into which an effusion of blood has taken place. [hemato- + G. omphalos, umbilicus, + kele, hernia]

hematomyelia
hematomyelia (he′ma-to-me′e-le-a)

Hemorrhage into the substance of the spinal cord; it is usually a posttraumatic lesion but may also be encountered in instances of spinal cord capillary telangiectases. SYN: hematorrhachis interna, myelapoplexy, myelorrhagia. [hemato- + G. myelos, marrow]

hematomyelopore
hematomyelopore (he′ma-to-mi′e-lo-por)

Formation of porosities in the spinal cord as a result of hemorrhages. [hemato- + G. myelos, marrow, + poros, a pore]

hematonic
hematonic (he-ma-ton′ik, hem-a-)

SYN: hematinic.

hematopathology
hematopathology (he′ma-to-path-ol′o-je, hem′a-)

The division of pathology concerned with diseases of the blood and of hemopoietic and lymphoid tissues. SYN: hemopathology. [hemato- + G. pathos, suffering, + logos, study]

hematopathy
hematopathy (he-ma-top′a-the, hem-a-)

SYN: hemopathy.

hematopenia
hematopenia (he′ma-to-pe′ne-a, hem′a-)

Deficiency of blood, including hypocytosis or cytopenia. [hemato- + G. penia, poverty]

hematophagia
hematophagia (he′ma-to-fa′je-a, hem′a-)

Living on the blood of another animal, as does the vampire bat or a leech. SYN: hemophagia. [hemato- + G. phago, to eat]

hematophagous
hematophagous (he′ma-tof′a-gus, hem′a-)

Subsisting on blood. [hemato- + G. phago, to eat]

hematophagus
hematophagus (he′ma-tof′a-gus, hem′a-)

A blood eater, especially bloodsucking insects. [hemato- + G. phago, to eat]

hematoplastic
hematoplastic (he′ma-to-plas′tik, hem′a)

SYN: hemopoietic. [hemato- + G. plasso, to form]

hematopoiesis
hematopoiesis (he′ma-to-poy-e′sis, hem′a-)

SYN: hemopoiesis.

hematopoietic
hematopoietic (he′ma-to-poy-et′ik)

SYN: hemopoietic.

hematopoietin
hematopoietin (he′ma-to-poy′e-tin, hem′a-)

SYN: erythropoietin.

hematoporphyria
hematoporphyria (he′ma-to-por-fir′e-a, hem′a-)

Obsolete term for any disorder of porphyrin metabolism, regardless of the cause. [hemato- + G. porphyra, purple]

hematoporphyrin
hematoporphyrin (he′ma-to-por′fi-rin, hem′a-)

A dark red, almost purple, porphyrin resulting from the decomposition of hemoglobin; chemical composition is that of heme with the iron removed and the two vinyl (–CH&dbond;CH₂) groups hydrated to hydroxyethyl (–CH(OH)–CH₃). SYN: hemoporphyrin.

hematoporphyrinemia
hematoporphyrinemia (he′ma-to-por′fi-ri-ne′me-a, hem′a-)

Older term used to designate the occurrence of hematoporphyrin in the circulating blood.

hematoporphyrinuria
hematoporphyrinuria (he′ma-to-por′fi-ri-noo′re-a, hem′a-)

Older term used to designate enhanced urinary excretion of porphyrins.

hematopsia
hematopsia (he-ma-top′se-a, hem-a-)

SYN: hemophthalmia. [hemato- + G. opsis, vision]

hematorrhachis
hematorrhachis (he-ma-tor′a-kis, hem-a-)

A spinal hemorrhage. [hemato- + G. rhachis, spine]
h. externa hemorrhage into the spinal canal external to the cord, either within or outside the dura. SYN: extradural h., subdural h..
extradural h. SYN: h. externa.
h. interna SYN: hematomyelia.
subdural h. SYN: h. externa.

hematosalpinx
hematosalpinx (he′ma-to-sal′pinks, hem′a-)

Collection of blood in a tube, often associated with a tubal pregnancy. SYN: hemosalpinx. [hemato- + G. salpinx, a trumpet]

hematosepsis
hematosepsis (he′ma-to-sep′sis, hem′a)

Obsolete term for septicemia.

hematosin
hematosin (he-ma-to′sin, hem-a-)

SYN: hematin.

hematosis
hematosis (he-ma-to′sis, hem-a-)

1. SYN: hemopoiesis. 2. Oxygenation of the venous blood in the lungs.

hematospectroscope
hematospectroscope (he′ma-to-spek′tro-skop, hem′a-)

A spectroscope especially adapted to examination of the blood.

hematospectroscopy
hematospectroscopy (he′ma-to-spek-tros′ko-pe, hem′a-)

Examination of the blood by means of a spectroscope.

hematospermatocele
hematospermatocele (he′ma-to-sper′ma-to-sel, hem′a-)

A spermatocele that contains blood.

hematospermia
hematospermia (he′ma-to-sper′me-a, hem′a-)

SYN: hemospermia.

hematostatic
hematostatic (he′ma-to-stat′ik, hem′a-)

1. Variant of hemostatic. 2. Due to stagnation or arrest of blood in the vessels of the part.

hematostaxis
hematostaxis (he′ma-to-stak′sis, hem′a-)

Spontaneous bleeding due to a disease of the blood. [hemato- + G. staxis, a dripping]

hematosteon
hematosteon (he-ma-tos′te-on, hem-a)

Bleeding in the medullary cavity of a bone. [hemato- + G. osteon, bone]

hematothermal
hematothermal (he′ma-to-ther′mal, hem′a-)

SYN: homeothermic.

hematotoxin
hematotoxin (he′ma-to-toks′in, hem′a-)

SYN: hemotoxin.

hematotropic
hematotropic (he′ma-to-trop′ik, hem′a-)

SYN: hemotropic.

hematotympanum
hematotympanum (he′ma-to-tim′pan-um, hem′a-)

SYN: hemotympanum.

hematoxin
hematoxin (he-ma-toks′in, hem-a)

SYN: hemotoxin.

hematoxylin
hematoxylin (he-ma-toks′i-lin, hem-a-) [C.I. 75290]

A crystalline compound, containing the coloring matter of Haematoxylon campechianum (logwood), from which it is obtained by extraction with ether. It is used as a dye in histology, especially for cell nuclei and chromosomes, muscle cross-striations, and enterochromaffin cells; its staining properties depend upon its oxidation to hematein and mordanting with chrome and iron alums. It is also used as an indicator (red to yellow at pH 0.0 to 1.0, yellow to violet at pH 5.0 to 6.0).
Boehmer h. an alum type of h. in which natural ripening occurs in about 8 to 10 days, and the solution is good for many months.
Delafield h. an alum type of h. used in histology; natural ripening takes about 2 months and the solution is good for years.
Harris h. an alum type of h. similar to Delafield h., but which uses chemical ripening to produce oxidation of h. for immediate use.
iron h. unique ferric lakes of hematein that produce deep blue-black stains; useful for studies of cytologic detail, such as chromosomes, spindle fibers, Golgi apparatus, myofibrils, and mitochrondria; also useful to demonstrate Entamoeba histolytica. SEE ALSO: Heidenhain iron h. stain, Weigert iron h. stain.
phosphotungstic acid h. (PTAH) a stain with broad application in cytology and histology; nuclei, mitochrondria, fibrin, neuroglial fibrils, and cross-striations of skeletal and cardiac muscle stain blue; cartilage ground substance, bone reticulum, and elastin appear in shades of yellow-orange and brownish red; also useful for demonstrating abnormal or diseased astrocytes, often in combination with periodic acid-Schiff stain and Luxol fast blue. SYN: Mallory phosphotungstic acid h. stain.

hematozoic
hematozoic (he′ma-to-zo′ik, hem′a)

SYN: hemozoic.

hematozoon
hematozoon (he′ma-to-zo′on, hem′a-)

SYN: hemozoon.

hematuria
hematuria (he-ma-too′-re-a, hem-a-)

Presence of blood or red blood cells in the urine. [hemato- + G. ouron, urine]
Egyptian h. SYN: schistosomiasis haematobium.
endemic h. SYN: schistosomiasis haematobium.
false h. SYN: pseudohematuria.
gross h. the presence of blood in the urine in sufficient quantity to be visible to the naked eye.
initial h. the presence of blood only in the first fraction of voided urine, usually indicating a urethral or prostatic source of bleeding.
microscopic h. presence of blood cells in urine, visible only under the microscope.
painful h. h. associated with dysuria, usually indicating the coexistence of infection, trauma, calculi, or foreign bodies within the lower urinary tract.
painless h. h. not associated with dysuria, often connoting a vascular or neoplastic etiology.
renal h. h. resulting from extravasation of blood into the glomerular spaces, or tubules, or pelves of the kidneys.
terminal h. the presence of blood only in the last fraction of voided urine, usually indicating a prostatic source of bleeding.
total h. blood throughout all fractions of the voided urine, commonly indicating an upper or mid-urinary tract source of bleeding.
urethral h. h. in which the site of bleeding is in the urethra.
vesical h. h. in which the site of bleeding is in the urinary bladder.

heme
heme (hem)

1. The porphyrin chelate of iron in which the iron is Fe(II) (or Fe²⁺); the oxygen-carrying, color-furnishing, prosthetic group of hemoglobin. 2. Iron complexed with nonporphyrins but related tetrapyrrole structures ( e.g., biliverdin h.). 3. Iron chelated with any porphyrin, irrespective of the valence state of the iron atom. SYN: ferroheme, ferroprotoporphyrin, reduced hematin. [G. haima, blood]
h. a a derivative of h. found in cytochrome aa₃.
h. c a derivative of h. found in cytochromes c, b₄, and f.

hemeralopia
hemeralopia (hem′er-al-o′pe-a)

Inability to see as distinctly in a bright light as in reduced illumination; seen in patients with impaired cone function. SYN: day blindness, hemeranopia, night sight. [G. hemera, day, + alaos, obscure, + ops, eye]

hemeranopia
hemeranopia (hem′er-a-no′pe-a)

SYN: hemeralopia. [G. hemera, day, + an-, priv., + ops, eye]

hemerythrins
hemerythrins (he-me-rith′rinz, hem-e-)

Iron-containing, oxygen-binding proteins in certain invertebrates, with molecular weights approximately that of hemoglobin but differing from hemoglobin in that the molecules do not contain porphyrin groups. Oxygenated h. is oxyhemerythrin. [G. haima, blood, + G. erythros, red, + -in]

hemi- hemi-

One-half. Cf.:semi-. [G.]

hemiacardius
hemiacardius (hem′e-a-kar′de-us)

One of twin fetuses, in which only a part of the circulation is effected by its own heart, the rest by the heart of the other twin. [hemi- + G. a- priv. + kardia, heart]

hemiacetal
hemiacetal (hem′e-as′e-tal)

RCH(OH)OR′, a product of the addition of an alcohol to an aldehyde (an acetal is formed by the addition of an alcohol to a h.). In the aldose sugars, the h. formation is internal and labile, brought about by the 4-OH or 5-OH attack on the carbonyl O, yielding the furanose or pyranose structures; the h. forms of the sugars are involved in all polysaccharides, as glycosyls or glycosides. SEE ALSO: hemiketal, acetal.

hemiacrosomia
hemiacrosomia (hem′e-ak-ro-so′me-a)

A congenital form of hemihypertrophy of an extremity. [hemi- + G. akron, extremity, + soma, body]

hemiageusia
hemiageusia (hem′e-a-goo′se-a)

Loss of taste from one side of the tongue. SYN: hemiageustia, hemigeusia. [hemi- + G. a- priv. + geusis, taste]

hemiageustia
hemiageustia (hem′e-a-goos′te-a)

SYN: hemiageusia.

hemialgia
hemialgia (hem-e-al′je-a)

Pain affecting one entire half of the body. [hemi- + G. algos, pain]

hemianalgesia
hemianalgesia (hem′e-an′al-je′ze-a)

Analgesia affecting one side of the body.

hemianencephaly
hemianencephaly (hem′e-an-en-sef′a-le)

Anencephaly on one side only, or involving one side much more extensively than the other.

hemianesthesia
hemianesthesia (hem′e-an-es-the′-ze-a)

Anesthesia on one side of the body. SYN: unilateral anesthesia.
alternate h. h. affecting the head on one side and the body and extremities on the other side. SYN: crossed h..
crossed h. SYN: alternate h..

hemianopia
hemianopia (hem′e-a-no′pe-a)

Loss of vision for one half of the visual field of one or both eyes. SYN: hemianopsia.
absolute h. hemianopsia in which the affected field is totally insensitive to all visual stimuli. SYN: complete h..
altitudinal h. a defect in the visual field in which the upper or lower half is lost; may be unilateral or bilateral.
binasal h. blindness in the nasal field of vision of both eyes.
bitemporal h. blindness in the temporal field of vision of both eyes.
complete h. SYN: absolute h..
congruous h. hemianopsia in which the visual field defects in both eyes are completely symmetric in extent and intensity.
crossed h. SYN: heteronymous h..
heteronymous h. attitudinal h. involving the upper field of one eye and the lower field of the other; or a binasal or bitemporal h.. SYN: crossed h..
homonymous h. blindness in the corresponding (right or left) field of vision of each eye.
incomplete h. hemianopsia involving less than half the visual field of each eye.
incongruous h. an incomplete or asymmetric homonymous hemianopsia.
pseudo-h. a condition in which individual stimuli are seen correctly, but when the nasal visual field of one eye and the temporal visual field of the fellow eye are stimulated simultaneously, one field is blind. SYN: visual extinction.
quadrantic h. SYN: quadrantanopia.
unilateral h. loss of sight in one-half of the visual field of one eye only. SYN: unilocular h..
unilocular h. SYN: unilateral h..

hemianopic
hemianopic (hem′e-an-op′ik)

Pertaining to hemianopia.

hemianopsia
hemianopsia (hem′e-an-op′se-a)

SYN: hemianopia. [hemi- + G. an- priv. + opsis, vision]

hemianosmia
hemianosmia (hem′e-an-oz′me-a)

Loss of the sense of smell on one side. [hemi- + G. an- priv. + osme, smell]

hemiaplasia
hemiaplasia (hem′e-a-pla′ze-a)

Absence of one lobe of a bilobed organ; used especially with reference to the thyroid gland. [hemi- + aplasia]

hemiapraxia
hemiapraxia (hem′e-a-prak′se-a)

Apraxia affecting one side of the body.

hemiarthroplasty
hemiarthroplasty (hem-e-ar′thro-plas-te)

Arthroplasty in which one joint surface is replaced with artificial material, usually metal.

hemiasynergia
hemiasynergia (hem′e-a-sin-er′je-a)

Asynergia affecting one side of the body.

hemiataxia
hemiataxia (hem′e-a-tak′se-a)

Ataxia affecting one side of the body.

hemiathetosis
hemiathetosis (hem′e-ath′e-to′sis)

Athetosis affecting one hand, or one hand and foot, only.

hemiatrophy
hemiatrophy (hem-e-at′ro-fe)

Atrophy of one lateral half of a part or of an organ, as the face or tongue.
facial h. atrophy, usually progressive, affecting the tissues of one side of the face. SYN: facial h. of Romberg, Romberg disease, Romberg syndrome.
facial h. of Romberg SYN: facial h..
lingual h. atrophy of one lateral half of the tongue.

hemiballism
hemiballism (hem-e-bal′izm)

SYN: hemiballismus. [hemi- + G. ballismos, jumping about]

hemiballismus
hemiballismus (hem-e-bal-iz′mus)

Ballism involving one side of the body. SYN: hemiballism. [hemi- + G. ballismos, jumping about]

hemiblock
hemiblock (hem′e-blok)

SYN: divisional block.

hemic
hemic (he′mik)

SYN: hematic (1) .

hemicardia
hemicardia (hem-e-kar′de-a)

1. Either lateral half, including atrium and ventricle, of the heart. 2. A congenital malformation of the heart in which only two of the usual four chambers are formed. [hemi- + G. kardia, heart]
h. dextra right side of the heart.
h. sinistra left side of the heart.

hemicellulose
hemicellulose (hem-e-sel′u-los)

Plant cell-wall polysaccharides closely associated with cellulose, such as xylans, mannans, and galactans. SYN: cellulosan.

hemicentrum
hemicentrum (hem′e-sen′trum)

One of the two lateral halves of the body of the vertebra. [hemi- + G. kentron, center]

hemicephalalgia
hemicephalalgia (hem′e-sef′a-lal′je-a)

The unilateral headache characteristic of typical migraine. SYN: hemicrania (2) . [hemi- + G. kephale, head, + algos, pain]

hemicephalia
hemicephalia (hem-e-se-fa′le-a)

Congenital failure of the cerebrum to develop normally; usually the cerebellum and basal ganglia are represented at least in rudimentary form. SYN: partial anencephaly. [hemi- + G. kephale, head]

hemicerebrum
hemicerebrum (hem′e-ser′e-brum)

A cerebral hemisphere.

hemicholinium
hemicholinium (hem′e-ko-lin′e-um)

A chemical which interferes with the synthesis of acetylcholine in cholinergic nerve terminals.

Hemichorda
Hemichorda (hem-e-kor′da)

SYN: Hemichordata.

Hemichordata
Hemichordata (hem′e-kor-da′ta)

A phylum composed of soft-bodied, bilaterally symmetric wormlike marine animals with gill-slits to the pharynx and a conical proboscis; a ciliated larval stage resembles that of echinoderms. SYN: Hemichorda. [hemi- + Mod. L. chordata, having a notochord, fr. G. chorde, string]

hemichorea
hemichorea (hem′e-kor-e′a)

Chorea involving the muscles on one side only. SYN: hemilateral chorea.

hemicolectomy
hemicolectomy (hem′e-ko-lek′to-me)

Removal of the right or left side of the colon. [hemi- + G. kolon, colon, + ektome, excision]

hemicorporectomy
hemicorporectomy (hem′e-kor-po-rek′to-me)

Surgical removal of the lower half of the body, including the lower extremities, bony pelvis, genitalia, and various of the pelvic contents including the lower part of the rectum and the anus. [hemi- + L. corpus, body, + G. ektome, excision]

hemicrania
hemicrania (hem-e-kra′ne-a)

1. SYN: migraine. 2. SYN: hemicephalalgia. [hemi- + G. kranion, skull]

hemicraniectomy
hemicraniectomy (hem′e-kra-ne-ek′tome)

SYN: hemicraniotomy. [hemi- + G. kranion, skull, + ektome, excision]

hemicraniosis
hemicraniosis (hem′e-kra-ne-o′sis)

Enlargement of one side of the cranium.

hemicraniotomy
hemicraniotomy (hem′e-kra-ne-ot′o-me)

Separation and reflection of the greater part or all of one half of the cranium, as a preliminary to an operation upon the brain. SYN: hemicraniectomy. [hemi- + G. kranion, skull, + tome, cut]

hemidesmosomes
hemidesmosomes (hem-e-des′mo-somz)

Half desmosomes that occur on the basal surface of the stratum basalis of stratified squamous epithelium.

hemidiaphoresis
hemidiaphoresis (hem′e-di-a-fo-re′sis)

Diaphoresis, or sweating, on one side of the body. SYN: hemidrosis, hemihidrosis.

hemidrosis
hemidrosis (hem-i-dro′sis)

SYN: hemidiaphoresis.

hemidysesthesia
hemidysesthesia (hem′e-dis-es-the′-ze-a)

Dysesthesia affecting one side of the body.

hemidystrophy
hemidystrophy (hem-e-dis′tro-fe)

Underdevelopment of one lateral half of the body. [hemi- + G. dys-, ill, + trophe, nourishment, growth]

hemiectromelia
hemiectromelia (hem′e-ek-tro-me′le-a)

Defective development of the limbs on one side of the body. [hemi- + ectromelia]

hemifacial
hemifacial (hem-e-fa′shal)

Pertaining to one side of the face.

hemigastrectomy
hemigastrectomy (hem′e-gas-trek-to-me)

Excision of the distal one-half of the stomach.

hemigeusia
hemigeusia (hem′e-goo′se-a)

SYN: hemiageusia.

hemiglossal
hemiglossal (hem′e-glos′al)

SYN: hemilingual. [hemi- + G. glossa, tongue]

hemiglossectomy
hemiglossectomy (hem′e-glos-ek′to-me)

Surgical removal of one-half of the tongue. [hemi- + G. glossa, tongue, + ektome, excision]

hemiglossitis
hemiglossitis (hem′e-glos-i′tis)

A vesicular eruption on one side of the tongue and the corresponding inner surface of the cheek, probably herpetic. [hemi- + G. glossa, tongue, + -itis, inflammation]

hemignathia
hemignathia (hem-e-nath′e-a)

Defective development of one side of the mandible. [hemi- + G. gnathos, jaw]

hemihepatectomy
hemihepatectomy (hem′e-hep-a-tek′to-me)

Surgical removal of one-half or a lobe of the liver.

hemihidrosis
hemihidrosis (hem′e-hi-dro′sis)

SYN: hemidiaphoresis.

hemihydranencephaly
hemihydranencephaly (hem-e-hi′dran-en-sef′a-le)

A unilateral form of hydranencephaly.

hemihypalgesia
hemihypalgesia (hem′e-hi-pal-je′ze-a)

Hypalgesia affecting one side of the body.

hemihyperesthesia
hemihyperesthesia (hem′e-hi′per-es-the′ze-a)

Hyperesthesia, or increased tactile and painful sensibility, affecting one side of the body.

hemihyperhidrosis
hemihyperhidrosis (hem′e-hi-per-hi-dro′sis)

Excessive sweating confined to one side of the body. [hemi- + G. hyper, over, + hidrosis, sweating]

hemihypertonia
hemihypertonia (hem′e-hi-per-to′ne-a)

Exaggerated muscular tonicity on one side of the body. [hemi- + G. hyper, over, + tonos, tone]

hemihypertrophy
hemihypertrophy (hem′e-hi-per′tro-fe)

Muscular or osseous hypertrophy of one side of the face or body.

hemihypesthesia
hemihypesthesia (hem′e-hi-pes-the′ze-a)

Diminished sensibility in one side of the body. SYN: hemihypoesthesia. [hemi- + G. hypo, under, + aestheses, sensation]

hemihypoesthesia
hemihypoesthesia (hem′e-hi-po-es-the′ze-a)

SYN: hemihypesthesia. [hemi- + G. hypo, under, + aistheses, sensation]

hemihypotonia
hemihypotonia (hem′e-hi-po-to′ne-a)

Partial loss of muscular tonicity on one side of the body. [hemi- + G. hypo, under, + tonos, tone]

hemikaryon
hemikaryon (hem-i-kar′i-on)

A cell nucleus containing a haploid set of chromosomes. [hemi- + G. karyon, nut (nucleus)]

hemiketal
hemiketal (hem′e-ke-tal)

RC(R′)(OH)OR&dprime;, a product of the addition of an alcohol to a ketone. In the ketose sugars, the h. formation is from an attack by an internal OH on the ketone carbonyl leading to intramolecular cyclization (furanose or pyranose); the h. forms of the sugars are involved in polysaccharide formation, as glycosyls or glycosides. SEE ALSO: hemiacetal, ketal.

hemilaminectomy
hemilaminectomy (hem′e-lam-i-nek′to-me)

Removal of a portion of a vertebral lamina, usually performed for exploration of, access to, or decompression of the intraspinal contents. [hemi- + L. lamina, layer, + G. ektome, excision]

hemilaryngectomy
hemilaryngectomy (hem′e-lar-in-jek′to-me)

Excision of one lateral half of the larynx. [hemi- + G. larnyx (laryng-), larynx, + ektome, excision]

hemilateral
hemilateral (hem-e-lat′er-al)

Relating to one lateral half.

hemilesion
hemilesion (hem-e-le′zhun)

A unilateral lesion.

hemilingual
hemilingual (hem-e-ling′gwal)

Relating to one lateral half of the tongue. SYN: hemiglossal. [hemi- + L. lingua, tongue]

hemimacroglossia
hemimacroglossia (hem′e-mak′ro-glos′e-a)

Enlargement of half the tongue. [hemi- + G. makros, large, + glossa, tongue]

hemimandibulectomy
hemimandibulectomy (hem′e-man-dib′u-lek′to-me)

Resection of one-half of the mandible.

hemimelia
hemimelia (hem-e-mel′e-a)

Congenital partial absence of a part of an extremity; for example, absence of the fibula and presence of the tibia. [hemi- + G. melos,limb, + -ia]

hemimetabolous
hemimetabolous (hem′e-me-tab′o-lus)

Pertaining to a member of the series of insect orders, the Hemimetabola, in which simple or incomplete metamorphosis is found. [hemi- + G. metabole, change]

hemin
hemin (hem′in)

1. Chloride of heme in which Fe²⁺ has become Fe³⁺. H. crystals are called Teichmann crystals, under crystal. 2. Any coordination complex of chloro(porphyrinato)iron(III). SYN: chlorohemin, factor X for Haemophilus, ferriheme chloride, ferriporphyrin chloride, ferriprotoporphyrin, hematin chloride.

hemiopalgia
hemiopalgia (hem′e-o-pal′je-a)

Pain in one eye, usually accompanied by hemicrania. [hemi- + G. ops, eye, + algos, pain]

hemipagus
hemipagus (hem-ip′a-gus)

Conjoined twins that are united laterally at the thorax; the zone of union may also involve the neck and jaws. See conjoined twins, under twin. [hemi- + G. pagos, something fixed]

hemipancreatectomy
hemipancreatectomy (hem′e-pan′-kre-a- tek′to-me)

Surgical resection of half of the pancreas.

hemiparesis
hemiparesis (hem-e-pa-re′sis, -par′e-sis)

Weakness affecting one side of the body.

hemipelvectomy
hemipelvectomy (hem′e-pel-vek′to-me)

Amputation of an entire lower extremity together with a portion of the ipsilateral pelvis. SYN: hindquarter amputation, Jaboulay amputation. [hemi- + L. pelvis, basin (pelvis), + G. ektome, excision]

hemiplegia
hemiplegia (hem-e-ple′je-a)

Paralysis of one side of the body. [hemi- + G. plege, a stroke]
alternating h. h. on one side with contralateral cranial nerve palsies. SYN: crossed h., crossed paralysis.
contralateral h. paralysis occurring on the side opposite to the causal central lesion.
crossed h. SYN: alternating h..
double h. SYN: diplegia.
facial h. paralysis of one side of the face, the muscles of the extremities being unaffected.
infantile h. acute hemiparesis that occurs in infancy and is usually caused by a vascular accident such as cerebral infarction or thrombosis; frequently associated with seizures.
spastic h. a h. with increased tone in the antigravity muscles of the affected side.

hemiplegic
hemiplegic (hem-e-ple′jik)

Relating to hemiplegia.

Hemiptera
Hemiptera (hem-ip′ter-a)

An arthropod order of the class Insecta that includes many plant lice and other true bugs; those of the subfamily Triatominae are bloodsuckers and of medical importance. The best known species is Cimex lectularius, the common bedbug. [hemi- + G. pteron, wing]

hemisection
hemisection (hem-e-sek′shun)

Surgical removal of a root and its related coronal portion of a multirooted tooth.

hemisensory
hemisensory (hem′e-sen′sor-e)

Loss of sensation on one side of the body. Cf.:hemianesthesia.

hemiseptum
hemiseptum (hem-e-sep′tum)

A lateral half of any septum.

hemispasm
hemispasm (hem′e-spazm)

A spasm affecting one or more muscles of one side of the face or body.

hemisphere
hemisphere (hem′i-sfer) [TA]

Half of a spherical structure. SYN: cerebral h. (1) [TA] . [hemi- + G. sphaira, ball, globe]
h. of bulb of penis one of the lateral halves of the bulb of the penis that are separated by a median groove on the posterior part of the undersurface. SYN: hemispherium bulbi urethrae.
h. of cerebellum SYN: h. of cerebellum HII–HX.
h. of cerebellum HII–HX the large part of the cerebellum lateral to the vermis cerebelli. SYN: hemispherium cerebelli [HII–HX] [TA] , hemispherium (2) [TA] , h. of cerebellum, hemisphericum cerebelli HII–HX, hemisphericum.
cerebral h. [TA] 1. SYN: h.. 2. the large mass of the telencephalon, on either side of the midline, consisting of the cerebral cortex and its associated fiber systems, together with the deeper-lying subcortical telencephalic nuclei ( i.e., basal ganglia [nuclei]). SYN: hemispherium cerebri [TA] , hemispherium (1) [TA] .
dominant h. that cerebral h. containing the representation of speech and controlling the arm and leg used preferentially in skilled movements; usually the left h..

hemispherectomy
hemispherectomy (hem′e-sfer-ek′to-me)

Excision of one cerebral hemisphere; undertaken for malignant tumors, intractable epilepsy usually associated with infantile hemiplegia due to birth injury, and other cerebral conditions.

hemisphericum
hemisphericum

SYN: hemisphere of cerebellum HII–HX.
h. cerebelli HII–HX SYN: hemisphere of cerebellum HII–HX.

hemispherium
hemispherium (hem′i-sfer′e-um) [TA]

1. SYN: cerebral hemisphere. 2. SYN: hemisphere of cerebellum HII–HX. [G. hemisphairion]
h. bulbi urethrae SYN: hemisphere of bulb of penis.
h. cerebelli [HII–HX] [TA] SYN: hemisphere of cerebellum HII–HX.
h. cerebri [TA] SYN: cerebral hemisphere.

Hemispora
Hemispora (hem′e-spo′ra)

Generic name for certain species of Fungi Imperfecti in which chains of conidia develop from tubular structures that form as the result of a constriction at the end of each of a series of short hyphal branches; close septations divide the contents of the tube into relatively square, thick-walled, deeply staining segments that eventually separate and become rounded, thick-walled spores with rough surfaces. H. organisms occur fairly frequently as contaminants in cultures for other fungi; they are usually regarded as nonpathogenic forms, but there are a few reported instances in which they were apparently the causal agents of disease. [hemi- + G. sporos, seed]

hemistrumectomy
hemistrumectomy (hem′e-stroo-mek′to-me)

Rarely used term for excision of approximately one-half of a goiter. [hemi- + L. struma, + G. ektome, excision]

hemisubstance
hemisubstance (hem′e-sub′stans)

An amorphous substance found in cell walls.

hemisyndrome
hemisyndrome (hem′e-sin-drom)

1. A condition in which one-half of the body is atrophied or hypertrophied. 2. Unilateral lesion of the spinal cord.

hemiterpene
hemiterpene (hem-e-ter′pen)

Isoprene or a derivative of a single isoprene.

hemithermoanesthesia
hemithermoanesthesia (hem′e-ther′mo-an-es-the′ze-a)

Loss of sensibility to heat and cold affecting one side of the body.

hemithorax
hemithorax (hem-e-tho′raks)

One side of the thorax.

hemitremor
hemitremor (hem′e-trem′er, -tre′mer)

Tremor affecting the muscles of one side of the body.

hemitruncus
hemitruncus (hem′e-trunk′us)

A variant truncus arteriosus in which only one pulmonary artery originates from the truncal artery.

hemivertebra
hemivertebra (hem-e-ver′te-bra)

A congenital defect of the spine in which one side of a vertebra fails to develop completely.

hemizygosity
hemizygosity (hem′i-zi-gos′i-te)

The state of being hemizygous.

hemizygote
hemizygote (hem-i-zi′got)

An individual hemizygous with respect to one or more specified loci; e.g., a normal male is a h. with respect to the gene for all X-linked or Y-linked genes in his genome. [hemi- + G. zygotos, yoked]

hemizygotic
hemizygotic (hem′i-zi-got′ik)

SYN: hemizygous.

hemizygous
hemizygous (hem-i-zi′gus)

Having unpaired genes in an otherwise diploid cell; males are normally h. for genes on both sex chromosomes. SYN: hemizygotic.

hemlock
hemlock (hem′lok)

SYN: conium.

hemo- hemo-

Combining form denoting blood. SEE ALSO: hem-, hemat-, hemato-. [G. haima]

hemoagglutination
hemoagglutination (he′mo-a-gloo′ti-na′shun)

SYN: hemagglutination.

hemoagglutinin
hemoagglutinin (he′mo-a-gloo′ti-nin)

SYN: hemagglutinin.

hemoantitoxin
hemoantitoxin (he′mo-an-ti-tok′sin)

An antibody that neutralizes the effects of a hemotoxin, such as the hemolytic material in cobra venom.

hemobilia
hemobilia (he-mo-bil′e-a)

Bleeding into the biliary passages, usually as a result of hepatic trauma or a neoplasm in the liver or biliary tract. SYN: hematobilia.

hemoblast
hemoblast (hem′o-blast)

SYN: hemocytoblast.
lymphoid h. of Pappenheim obsolete term for pronormoblast. SEE ALSO: erythroblast.

hemoblastosis
hemoblastosis (he′mo-blas-to′sis)

A proliferative condition of the hematopoietic tissues in general.

hemocatharsis
hemocatharsis (he′mo-ka-thar′sis)

Cleansing the blood. [hemo- + G. katharsis, a cleansing]

hemocatheresis
hemocatheresis (he′mo-kath-e-re′sis)

Destruction of the blood cells, especially of erythrocytes (hemocytocatheresis). [hemo- + G. kathairesis, destruction]

hemocatheretic
hemocatheretic (he′mo-kath-e-ret′ik)

Pertaining to or characterized by hemocatheresis.

hemocele
hemocele (he′mo-sel)

The system of blood-containing spaces pervading the body in arthropods. [hemo- + G. koiloma, cavity]

hemocholecystitis
hemocholecystitis (he′mo-ko′le-sis-ti′tis)

Hemorrhagic cholecystitis.

hemochromatosis
hemochromatosis (he′mo-kro-ma-to′sis)

A disorder of iron metabolism characterized by excessive absorption of ingested iron, saturation of iron-binding protein, and deposition of hemosiderin in tissue, particularly in the liver, pancreas, and skin; cirrhosis of the liver, diabetes (bronze diabetes), bronze pigmentation of the skin, and, eventually heart failure may occur; also can result from administration of large amounts of iron orally, by injection, or in forms of blood transfusion therapy. [hemo- + G. chroma, color, + -osis, condition]
exogenous h. hemosiderosis due to repeated blood transfusions; it can progress to pigmentary cirrhosis.
primary h. [MIM*235200] a specific inherited metabolic defect with increased absorption and accumulation of iron on a normal diet; autosomal recessive inheritance caused by a mutation in the h. gene (HFE) on 6p, less florid in females; juvenile h. may represent a homozygous state of the same gene.
secondary h. increased intake and accumulation of iron secondary to known cause, such as oral iron therapy or multiple transfusions.

hemochrome
hemochrome (he′mo-krom)

SYN: hemochromogen.

hemochromogen
hemochromogen (he-mo-kro′mo-jen)

Term originally used for combinations of ferro- or ferriporphyrins with 2 mol of a nitrogenous base or protein, e.g., pyridine ferroporphyrin. SYN: hemochrome. [hemo- + G. chroma, color, + -gen, producing]

hemoclasis
hemoclasis, hemoclasia (he-mok′la-sis, he′mo-kla′ze-a)

Rupture, dissolution (hemolysis), or other type of destruction of red blood cells. [hemo- + G. klasis, a breaking]

hemoclastic
hemoclastic (he′mo-klas′tik)

Pertaining to hemoclasis.

hemoconcentration
hemoconcentration (he′mo-kon-sen-tra′shun)

Decrease in the volume of plasma in relation to the number of red blood cells; increase in the concentration of red blood cells in the circulating blood.

hemoconia
hemoconia (he-mo-ko′ne-a)

An obsolete term for small refractive particles in the circulating blood, probably lipid material associated with fragmented stroma from red blood cells. SYN: blood dust, blood motes, dust corpuscles. [hemo- + G. konis, dust]

hemoconiosis
hemoconiosis (he′mo-ko-ne-o′sis)

A condition in which there is an abnormal amount of hemoconia in the blood.

hemocryoscopy
hemocryoscopy (he′mo-kri-os′ko-pe)

Determination of the freezing point of blood. [hemo- + G. kryos, cold, + skopeo, to examine]

hemocuprein
hemocuprein (he-mo-koo′pre-in)

SYN: cytocuprein.

hemocyanin
hemocyanin (he-mo-si′a-nin)

An oxygen-carrying pigment (molecular weights between 0.45 and 13 × 10⁶) of lower sea animals (including molluscs and crustacea) and arthropods; copper is an essential component, but it contains no heme; used as an experimental antigen.

hemocyte
hemocyte (he′mo-sit)

Any cell or formed element of the blood. SYN: hematocyte. [hemo- + G. kytos, a hollow (cell)]

hemocytoblast
hemocytoblast (he′mo-si′to-blast)

A blood cell derived from embryonic mesenchyme, characterized by basophilic cytoplasm and a relatively large nucleus with a spongy, loose network of chromatin and several nucleoli; mitochondria are extremely fine and delicate. Hemocytoblasts represent the primitive stem cells of the monophyletic theory of the origin of blood and have the potentiality of developing into erythroblasts, young forms of the granulocytic series, megakaryocytes, etc. SYN: hematocytoblast, hemoblast. [hemo- + G. kytos, cell, + blastos, germ]

hemocytocatheresis
hemocytocatheresis (he′mo-si′to-ka-ther′e-sis)

Hemolysis, or other type of destruction of red blood cells. [hemo- + G. kytos, a hollow (cell), + kathairesis, destruction]

hemocytolysis
hemocytolysis (he′mo-si-tol′i-sis)

The dissolution of blood cells, including hemolysis. SYN: hematocytolysis. [hemo- + G. kytos, cell, + lysis, dissolution]

hemocytometer
hemocytometer (he′mo-si-tom′e-ter)

An apparatus for estimating the number of blood cells in a quantitatively measured volume of blood; it consists of a glass pipette with an ampulla for collecting and diluting the blood, and a counting chamber marked in squares. SYN: hemacytometer, hematimeter, hematocytometer. [hemo- + G. kytos, cell, + metron, measure]

hemocytometry
hemocytometry (he′mo-si-tom′e-tre)

The counting of red blood cells.

hemocytotripsis
hemocytotripsis (he′mo-si-to-trip′sis)

Fragmentation or disintegration of blood cells by means of mechanical trauma, e.g., compression between hard surfaces. [hemo- + G. kytos, + tripsis, a grinding]

hemocytozoon
hemocytozoon (he′mo-si-to-zo′on)

A protozoon parasite of the blood cells. SYN: hemacytozoon, hematocytozoon. [hemo- + G. kytos, cell, + zoon, animal]

hemodiagnosis
hemodiagnosis (he′mo-di-ag-no′sis)

Diagnosis by means of examination of the blood.

hemodialysis
hemodialysis (he′mo-di-al′i-sis)

Dialysis of soluble substances and water from the blood by diffusion through a semipermeable membrane; separation of cellular elements and colloids from soluble substances is achieved by pore size in the membrane and rates of diffusion.

hemodialyzer
hemodialyzer (he-mo-di′a-li-zer)

A machine for hemodialysis in acute or chronic renal failure; toxic substances in the blood are removed by exposure to dialyzing fluid across a semipermeable membrane. SYN: artificial kidney.
ultrafiltration h. a h. that uses fluid pressure differentials to bring about loss (usually) of protein-free fluid from the blood to the bath.

hemodiastase
hemodiastase (he-mo-di′as-tas)

Blood amylase.

hemodilution
hemodilution (he′mo-di-loo′shun)

Increase in the volume of plasma in relation to red blood cells; reduced concentration of red blood cells in the circulation.

hemodynamic
hemodynamic (he′mo-di-nam′ik)

Relating to the physical aspects of the blood circulation.

hemodynamics
hemodynamics (he′mo-di-nam′iks)

The study of the dynamics of the blood circulation. [hemo- + G. dynamis, power]

hemodyscrasia
hemodyscrasia (he′mo-dis-kra′ze-a)

Any abnormal condition or disorder of the blood and hemopoietic tissue, used especially with reference to those resulting in changes in the formed elements. SYN: hematodyscrasia. [hemo- + G. dyscrasia, bad temperament]

hemodystrophy
hemodystrophy (he-mo-dis′tro-fe)

Any disease or abnormal condition of the blood and hemopoietic tissues, exclusive of simple transitory changes. SYN: hematodystrophy.

hemofiltration
hemofiltration (he′mo-fil-tra′shun)

A process, similar to hemodialysis, by which blood is dialyzed using ultrafiltration, and usually to remove a specific product of fluid volume.

hemoflagellates
hemoflagellates (he-mo-flaj′e-lats)

Protozoan flagellates in the family Trypanosomatidae that are parasitic in the blood of many species of domestic and wild animals and birds, and of humans; they include the genera Leishmania and Trypanosoma, several species of which are important pathogens. [hemo- + L. flagellum, dim. of flagrum, a whip]

hemofuscin
hemofuscin (he-mo-fus′in)

A brown pigment derived from hemoglobin that occurs in urine occasionally along with hemosiderin, usually indicative of increased red blood cell destruction; occurs also in the liver with hemosiderin in cases of hemochromatosis.

hemogenesis
hemogenesis (he-mo-jen′e-sis)

SYN: hemopoiesis.

hemogenic
hemogenic (he-mo-jen′ik)

SYN: hemopoietic.

hemoglobin
hemoglobin (Hb) (he-mo-glo′bin) [MIM*141800–142310]

The red respiratory protein of erythrocytes, consisting of approximately 3.8% heme and 96.2% globin, with a molecular weight of 64,450, which as oxyhemoglobin (HbO₂) transports oxygen from the lungs to the tissues where the oxygen is readily released and HbO₂ becomes Hb. When Hb is exposed to certain chemicals, its normal respiratory function is blocked; e.g., the oxygen in HbO₂ is easily displaced by carbon monoxide, thereby resulting in the formation of fairly stable carboxyhemoglobin (HbCO), as in asphyxiation resulting from inhalation of exhaust fumes from gasoline engines. When the iron in Hb is oxidized from the ferrous to ferric state, as in poisoning with nitrates and certain other chemicals, a nonrespiratory compound, methemoglobin (MetHb), is formed. In humans there are at least five kinds of normal Hb: two embryonic Hb's (Hb Gower-1, Hb Gower-2), fetal (Hb F), and two adult types (Hb A, Hb A₂). There are two α globin chains containing 141 amino acid residues, and two of another kind (β, γ, δ, ε, or ζ), each containing 146 amino acid residues in four of the Hb's. Hb Gower-1 has two ζ chains and two ε chains. The production of each kind of globin chain is controlled by a structural gene of similar Greek letter designation; normal individuals are homozygous for the normal allele at each locus. Substitution of one amino acid for another in the polypeptide chain can occur at any codon in any of the five loci and have resulted in the production of many hundreds of abnormal Hb types, most of no known clinical significance. In addition, deletions of one or more amino acid residues are known, as well as gene rearrangements due to unequal crossing over between homologous chromosomes. The Hb types below are the main abnormal types known to be of clinical significance. Newly discovered abnormal Hb types are first assigned a name, usually the location where discovered, and a molecular formula is added when determined. The formula consists of Greek letters to designate the basic chains, with subscript 2 if there are two identical chains; a superscript letter (^A if normal for adult Hb, etc.) is added, or the superscript may designate the site of amino acid substitution (numbering amino acid residues from the N-terminus of the polypeptide) and specifying the change, using standard abbreviations for the amino acids. There is an exhaustive listing of variant hemoglobins in MIM where a composite numbering system is used.
h. A [MIM*141800] normal adult Hb (Hb A) with formula α₂^Aβ₂^A or α₂β₂.
h. A₂ [MIM*141850] the normal Hb (Hb A₂) of the formula α₂^Aδ₂ or α₂δ₂, which makes up approximately 2.5% of the total adult h. concentration. At least 18 mutant variants of the δ chain have been reported.
h. A_Ic the major fraction of glycosylated h..
aberrant h. a mutant Hb that functions abnormally. Cf.:variant h..
h. anti-Lepore a group of abnormal hemoglobins similar to h. Lepore. These hemoglobins have normal α chains, but the non-α chain consists of the N-terminal portion of the β chain joined to the C-terminal portion of the δ chain. This is the opposite crossing over pattern observed in h. Lepore. Examples of h. anti-Lepore include Hb_Miyada, Hb P_Congo, Hb P_Nilotic, and Hb_{Lincoln Park}. There is also one variant that is both h. Lepore and h. anti-Lepore (Hb_Parchman). Cf.:h. Lepore.
h. Bart [MIM*142309] a Hb homotetramer (all four polypeptides identical) of formula γ₄, found in the early embryo and in α-thalassemia 2; not effective in oxygen transport; does not display a Bohr effect.
bile pigment h. SYN: choleglobin.
h. C [MIM*141900.0038] an abnormal Hb with substitution of lysyl residue for glutamyl at the 6th position of the β chain, of formula α₂2^Aβ₂^6Glu→Lys, this type reduces the normal plasticity of erythrocytes. Heterozygotes: Hb C trait, about 28–44% of total Hb is Hb C, no anemia. Homozygotes: nearly all Hb is Hb C, moderate normocytic hemolytic anemia. Individuals heterozygous for both Hb C and Hb S (Hb SC disease) and for Hb C and thalassemia are known, and have atypical hemolytic anemias; sickling is enhanced in Hb SC disease.
h. C_Georgetown, h. C_Harlem [MIM*141900.0039] two abnormal Hb's, both with the substitution of a valyl residue for a glutamyl residue at the 6th position of the β chain as in Hb S, and in addition, each has a second substitution of an asparaginyl residue for an aspartyl residue at position 73 of the β chain; both types cause sickling of erythrocytes similar to Hb S.
carbon monoxide h. SYN: carboxyhemoglobin.
h. Chesapeake (Hb_Chesapeake) [MIM*141800.0018] an abnormal h. with a single α chain substitution, molecular formula α₂^92Arg→Leuβ₂^A; heterozygotes have polycythemia, apparently to compensate for the increased oxygen affinity of this Hb, resulting in decreased liberation of oxygen in the tissues.
h. Constant Spring an abnormal h. having an extended polypeptide chain (31 additional amino acyl residues) on the α chain (thus, the α chain is 172 amino acids long); approximately 20% of the individuals with Hb H disease also have this defect.
h. D_Punjab [MIM*141900.0065] an abnormal Hb with a single β chain substitution, molecular formula α₂^Aβ₂^121Glu→Gln; heterozygotes are asymptomatic, homozygotes have mild hemolytic anemia; there is an increase in O₂ affinity; identical to h. D_{Los Angeles}, h. D_{North Carolina}, h. D_Portugal, h. D_Chicago, and hemoblogin Oak Ridge.
h. E [MIM*141900.0071] an abnormal Hb with a single β chain substitution, molecular formula α₂^Aβ₂^26Glu→Lys, common in Southeast Asia, especially Thailand; heterozygotes are asymptomatic with 35–45% Hb E; homozygotes have mild to moderate hemolytic anemia with 90–100% Hb E and the remainder Hb F.
embryonic h. h. Gower-1, h. Gower-2.
h. F [MIM*142200] normal fetal Hb (Hb F) of molecular formula α₂^Aγ₂^F, which is the major Hb component during intrauterine life, decreasing rapidly during infancy to reach a concentration of less than 0.5% in normal children and adults; the concentration of Hb F is increased in some hemoglobinopathies and in some cases of hypoplastic anemia, pernicious anemia, and leukemia; Hb F has a weaker affinity for 2,3-bisphosphoglycerate than does Hb A. More than 50 mutant variants of the γ chain have been reported. SYN: fetal h..
fetal h. SYN: h. F.
h. F (hereditary persistence of) [MIM*142200.0026] a condition due to an allele that depresses synthesis of β and δ chains (as in thalassemia), but this is fully compensated by increased γ chain synthesis and there is no anemia; there are 3 types: 1) African type, no β or δ chain synthesis by the chromosome with the abnormal gene, heterozygotes have 20–30% Hb F and Hb A₂ slightly decreased, homozygotes form no Hb A or Hb A₂; 2) Greek type, reduced β and δ chain synthesis, heterozygotes have 10–20% Hb F and normal Hb A₂; 3) Swiss type, heterozygotes have only 1 to 3% Hb F and normal Hb A₂.
glycosylated h. any one of four h. A fractions (A_Ia1, A_Ia2, A_Ib, or A_Ic) to which d-glucose and related monosaccharides are covalently linked; concentrations are increased in the erythrocytes of patients with diabetes mellitus and can be used as a retrospective index of glucose control over time in such patients.
h. Gower-1 a Hb of molecular formula ζ₂ε₂, found as a minor Hb in the early embryo; disappears by the third month of pregnancy in favor of h. Gower-2 and hemaglobin Portland and then by Hb F; the ζ chain has 141 amino acid residues. Synthesis of the ζ chain is deficient in cases of hydrops fetalis. Cf.:h. Gower-2, h. Portland.
h. Gower-2 a normal Hb of molecular formula α₂^Aε₂, which is a major Hb component of the early embryo; production of ε chains normally ceases at about the third month of fetal development and is replaced by Hb F. Cf.:h. Gower-1, h. Portland.
green h. SYN: choleglobin.
h. H [MIM*142309] a homotetramer of Hb (all four polypeptides identical) of molecular formula β₄, found only when α chain synthesis is depressed and not effective in oxygen transport. Hb H disease (α-thalassemia intermedia) is a thalassemialike syndrome in individuals heterozygous for both severe and mild genes for α-thalassemia; moderate anemia and red cell abnormalities with 25–35% Hb Bart at birth, but with Hb Bart later replaced by Hb H and with Hb A₂ decreased. Hb H shows no cooperativity with O₂ binding and does not exhibit a Bohr effect.
h. I [MIM*141800.0055] an abnormal Hb with a single α chain substitution, molecular formula α₂^16Lys→Gluβ₂^A; a thalassemialike syndrome has been found in persons heterozygous for both Hb I and α-thalassemia genes, with formation of about 70% Hb I.
h. J_Capetown [MIM*141800.0063] an abnormal Hb with a single α chain substitution, molecular formula α₂^92Arg→Glnβ₂^A; heterozygotes have polycythemia because of increased oxygen affinity of this Hb.
h. Kansas [MIM*141900.0145] an abnormal Hb of molecular formula α₂^Aβ₂^102Asn→Thr; found in association with familial cyanosis due to decreased oxygen affinity of this Hb.
h. Lepore [MIM 142000-various] a group of abnormal Hb's with normal α chains, but the non-α chains consist of the N-terminal portion of the δ chain joined to the C-terminal portion of the β chain, apparently as the result of nonhomologous pairing and crossing over between the genes for β and δ chains. The major types are Hb Lepore_Boston (identical to Hb Lepore_Washington), Hb Lepore_Hollandia, and Hb Lepore_Baltimore, which differ in the region of crossing over (δ87–β116, δ22–β50, and δ50–β86, respectively). Heterozygotes form about 10% Hb Lepore, normal amounts of Hb A₂, and moderately increased amounts of Hb F and usually have mild anemia, microcytosis, and hypochromia; homozygotes form only Hb Lepore and Hb F and have severe anemia. Cf.:h. anti-Lepore.
h. M [MIM*142310 & various] a group of abnormal Hb's in which a single amino acid substitution favors the formation of methemoglobin in spite of normal quantities of methemoglobin reductase. Strictly speaking, Hb's M are hemoglobins with mutations at the proximal or distal histidyl residues. Other Hb's M tend to favor the Fe(III) state. Heterozygotes have congenital methemoglobinemia; the homozygous state of these genes is unknown and is presumably lethal. Specific types include: Hb M_Iwate, α^87His→Tyr (α chain, position 87, histidine replaced by tyrosine); Hb M _{Hyde Park}, β^92His→Tyr; Hb M_Boston, α^58His→Tyr; Hb M_Saskatoon, β^63His→Tyr; Hb M_Milwaukee-1, β^67Val→Glu.
mean corpuscular h. (MCH) the h. content of the average red cell, calculated from the h. therein and the red cell count, in erythrocyte indices.
muscle h. SYN: myoglobin.
oxygenated h. SYN: oxyhemoglobin.
h. Portland a form of embryonic h. containing the ζ chains of h. Gower-1 and the γ chains of Hb F, thus having the formula ζ₂γ₂; essentially disappears by the third month of pregnancy. Cf.:h. Gower-1, h. Gower-2.
h. Rainier [MIM*141900-0232] an abnormal Hb of the molecular formula α₂^Aβ₂^145Tyr→Cys; heterozygotes have polycythemia because of increased oxygen affinity of this Hb.
reduced h. the form of Hb in red blood cells after the oxygen of oxyhemoglobin is released in the tissues.
h. S [MIM*141900] an abnormal Hb with substitution of valine for glutamic acid at the 6th position of the β chain; the formula is α₂^Aβ₂^S, or, more specifically, α₂^Aβ₂^6Glu→Val. Heterozygous state: sickle cell trait, no anemia, Hb S 20–45% of total, the rest Hb A. Homozygous state: sickle cell anemia, Hb S 75–100% of total, the rest Hb F or Hb A₂. SYN: sickle cell h..
sickle cell h. (Hb S) SYN: h. S.
unstable hemoglobins a group of rare Hb's with amino acid substitutions (or amino acid deletions in three types) that alter the three-dimensional shape of the globin in a manner that renders the molecule unstable; they have an increased but variable tendency to autooxidation and Heinz body formation and are associated with congenital nonspherocytic hemolytic anemia. The unstable β-chain abnormalities include Hb's Genova, Gun Hill, Hammersmith, Köln, Philly, Sabine, Santa Ana, Sydney, Wien, and Zürich; unstable α-chain abnormalities include Hb's Bibba, Sinai, and Torino.
variant h. a harmless mutant form of Hb.
h. Yakima [MIM*141900-0301] an abnormal Hb of the molecular formula α₂^Aβ₂^99Asp→His; heterozygotes have polycythemia because of increased oxygen affinity of this Hb.

hemoglobinemia
hemoglobinemia (he′mo-glo-bi-ne′me-a)

The presence of free hemoglobin in the blood plasma, as when intravascular hemolysis occurs.
paroxysmal nocturnal h. an acquired hematopoietic stem cell disorder characterized by formation of defective platelets, granulocytes, erythrocytes, and possibly lymphocytes. The red cell abnormality causes complement-mediated intravascular lysis, which may be expressed in an irregular or even occult manner.
puerperal h. SYN: postparturient hemoglobinuria.

hemoglobinocholia
hemoglobinocholia (he′mo-glo′bi-no-ko′le-a)

The presence of hemoglobin in the bile. [hemoglobin + G. chole, bile]

hemoglobinolysis
hemoglobinolysis (he′mo-glo-bi-nol′i-sis)

Destruction or chemical splitting of hemoglobin. SYN: hemoglobinopepsia. [hemoglobin + G. lysis, dissolution]

hemoglobinopathy
hemoglobinopathy (he′mo-glo-bi-nop′a-the)

A disorder or disease caused by or associated with the presence of abnormal hemoglobins in the blood, e.g., sickle cell disease, hemoglobin C, D, E, H, or I disorders. Occasionally, combinations of abnormal hemoglobins are seen in hemoglobinopathies. [hemoglobin + G. pathos, disease]

hemoglobinopepsia
hemoglobinopepsia (he-mo-glo′bi-no-pep′se-a)

SYN: hemoglobinolysis. [hemoglobin + G. pepsis, digestion]

hemoglobinophilic
hemoglobinophilic (he′mo-glo′bi-no-fil′ik)

Denoting certain microorganisms that cannot be cultured except in the presence of hemoglobin. [hemoglobin + G. phileo, to love]

hemoglobinuria
hemoglobinuria (he′mo-glo-bi-noo′re-a)

The presence of hemoglobin in the urine, including certain closely related pigments that are formed from slight alteration of the hemoglobin molecule; when present in sufficient quantities, they result in the urine being colored varying shades from light red-yellow to fairly dark red. [hemoglobin + G. ouron, urine]
epidemic h. the presence of hemoglobin, or of pigments derived from it, in the urine of young infants, attended with cyanosis, jaundice, and other conditions; may be due to secondary methemoglobinemia; also called Winckel disease.
intermittent h. recurrent episodic attacks of h. characteristic of paroxysmal nocturnal h. or paroxysmal cold h..
malarial h. a condition, now uncommon, resulting from Plasmodium falciparum infection (malignant tertian malaria with severe hemolysis); seen in whites after interrupted treatment. SYN: blackwater fever, hemoglobinuric fever, West African fever.
march h. a form occurring after marathon races, protracted marching, or heavy physical exercise.
paroxysmal cold h. a rare disorder in which acute severe hemolysis follows exposure to cold.
paroxysmal nocturnal h. an infrequent disorder with insidious onset (usually in the third or fourth decade) and chronic course, characterized by episodes of hemolytic anemia, h. (chiefly at night), pallor, icterus or bronzing of the skin, a moderate degree of splenomegaly, and sometimes hepatomegaly; red blood cells are usually macrocytic and vary considerably in size, but there is no evidence of spherocytosis, erythrophagocytosis, or abnormal leukocytes. The disorder is a result of an abnormality of the red cell membrane which makes the red cell unusually sensitive to lysis by complement. SYN: Marchiafava-Micheli anemia, Marchiafava-Micheli syndrome.
postparturient h. a sudden, severe hemolytic disease that appears sporadically in well-nourished dairy cows 2–4 weeks after calving, and usually occurs in stabled animals in the winter and early spring; the cause is not known, although the disease is often associated with hypophosphatemia. SYN: puerperal hemoglobinemia.
toxic h. h. occurring after the ingestion of various poisons, in certain blood diseases, and in certain infections.

hemoglobinuric
hemoglobinuric (he′mo-glo-bi-noo′rik)

Relating to or marked by hemoglobinuria.

hemogram
hemogram (he′mo-gram)

A complete detailed record of the findings in a thorough examination of the blood, especially with reference to the numbers, proportions, and morphologic features of the formed elements. [hemo- + G. gramma, a drawing]

hemohistioblast
hemohistioblast (he′mo-his′te-o-blast)

A primitive mesenchymal cell believed to be capable of developing into all types of blood cells, including monocytes, and into histiocytes. SYN: Ferrata cell, hematohistioblast. [hemo- + G. histion, web, + blastos, germ]

hemolamella
hemolamella (he′mo-la-mel′a)

Obsolete term for platelet.

hemolipase
hemolipase (he-mo-lip′as)

Blood lipase.

hemolith
hemolith (he′mo-lith)

A concretion in the wall of a blood vessel. [hemo- + G. lithos, stone]

hemology
hemology (he-mol′o-je)

SYN: hematology.

hemolymph
hemolymph (he′mo-limf)

1. The blood and lymph, in the sense of a “circulating tissue.” 2. The nutrient fluid of certain invertebrates. [hemo- + L. lympha, clear water]

hemolysate
hemolysate (he-mol′i-sat)

Preparation resulting from the lysis of erythrocytes.

hemolysin
hemolysin (he-mol′i-sin)

1. Any substance elaborated by a living agent and capable of causing lysis of red blood cells and liberation of their hemoglobin. SYN: erythrocytolysin, erythrolysin. 2. A sensitizing (complement-fixing) antibody that combines with red blood cells of the antigenic type that stimulated formation of the h., a fixing complement with the antibody-cell union resulting in lysis of the cells.
α h. α′ hemolysis.
β h. β hemolysis.
bacterial h. any hemolytic agent elaborated by various species of bacteria, or by certain strains within a species.
cold h. SYN: Donath-Landsteiner cold autoantibody.
heterophil h. a sensitizing antibody that can combine with red blood cells of various species (in addition to those used as the antigen in stimulating the formation of the h.), resulting in hemolysis when the proper amount of complement is present.
immune h. a sensitizing, complement-fixing, hemolytic antibody formed in an animal as the result of parenteral administration of red blood cells or whole blood from another species; immune h. may also be formed in human beings who are transfused with human blood that is antigenic in the recipient, e.g., the formation of anti-Rh antibody in an Rh-negative person who is treated with Rh-positive red blood cells.
natural h. h. occurring in the plasma of an animal of one species, e.g., a dog, which fixes complement with the red blood cells of some other species, e.g., a rabbit, thereby causing hemolysis of the cells of the rabbit, although the dog was not previously exposed to antigenic stimulation with such cells.
specific h. a sensitizing, complement-fixing, hemolytic antibody that reacts totally or completely with red blood cells of the antigenic type used to stimulate the formation of the h..
warm-cold h. h. which combines with red blood cells at temperatures below 20°C and are eluted at warmer temperatures, e.g., 30–37°C. See Donath-Landsteiner cold autoantibody, hemagglutinating cold autoantibody.

hemolysinogen
hemolysinogen (he′mo-li-sin′o-jen)

The antigenic material in red blood cells that stimulates the formation of hemolysin.

hemolysis
hemolysis (he-mol′i-sis)

Alteration, dissolution, or destruction of red blood cells in such a manner that hemoglobin is liberated into the medium in which the cells are suspended, e.g., by specific complement-fixing antibodies, toxins, various chemical agents, tonicity, alteration of temperature. SYN: erythrocytolysis, erythrolysis, hematolysis. [hemo- + G. lysis, destruction]
α′ h. h. observed in blood agar cultures of occasional strains of pneumococci or streptococci; the zone of h. about the colony is greenish caused by a partial decomposition of hemoglobin.
β h. complete or “true” h. observed in blood agar cultures of various bacteria, especially hemolytic streptococci and staphylococci; virtually all of the erythrocytes are destroyed in a relatively wide, regularly circumscribed, circular zone about the colony, thereby resulting in a clear “halo” of transparent agar; the zone of h. is frequently much wider than the diameter of the colony; the degree of change varies with species of erythrocytes.
biologic h. h. caused by materials elaborated by various living organisms.
conditioned h. SYN: immune h..
γ h. a term sometimes used to indicate that there is no h. in relation to bacterial colonies in or on blood agar; thus, nonhemolytic organisms may be referred to as producing γ h..
immune h. h. caused by complement when erythrocytes have been sensitized by specific complement-fixing antibody. SYN: conditioned h..
phenylhydrazine h. (fen′il-hi′-dra-zin) an in vitro test for glucose-6-phosphate dehydrogenase (G6PD) deficiency; hem olysis resulting from in vitro addition of phenylhydrazine to blood with red cells which are deficient in G6PD, with the appearance of Heinz-Ehrlich bodies.
venom h. that caused by hemolytic material in the venom of various species of snakes or other venomous animals.
viridans h. α′ h..

hemolytic
hemolytic (he-mo-lit′ik)

Destructive to blood cells, resulting in liberation of hemoglobin. SYN: hematolytic, hemotoxic (2) , hematotoxic, hematoxic.

hemolyzation
hemolyzation (he′mol-i-za′shun)

The production or occurrence of hemolysis.

hemolyze
hemolyze (he′mo-liz)

To produce hemolysis or liberation of the hemoglobin from red blood cells.

hemomediastinum
hemomediastinum (he′mo-me-de-a-sti′num)

Blood in the mediastinum.

hemometra
hemometra (he-mo-me′tra)

SYN: hematometra.

hemometry
hemometry (he-mom′e-tre)

SYN: hematometry.

hemopathology
hemopathology (he′mo-pa-thol′o-je)

SYN: hematopathology.

hemopathy
hemopathy (he-mop′a-the)

Any abnormal condition or disease of the blood or hemopoietic tissues. SYN: hematopathy. [hemo- + G. pathos, suffering]

hemoperfusion
hemoperfusion (he′mo-per-fu′zhun)

Passage of blood through columns of adsorptive material, such as activated charcoal, to remove toxic substances from the blood. [hemo- + L. perfusio, to pass through]

hemopericardium
hemopericardium (he′mo-par′-i-kar′de-um)

Blood in the pericardial sac.

hemoperitoneum
hemoperitoneum (he′mo-par-i-to-ne′um)

Blood in the peritoneal cavity.

hemopexin
hemopexin (hem-o-peks′in)

A serum glycoprotein related to β-globulins, with molecular weight around 57,000, containing 22% carbohydrate; important in binding heme and porphyrins, preventing excretion, and perhaps regulating heme in drug metabolism. [hemo- + G. pexis, fixation, + -in]

hemophagia
hemophagia (he-mo-fa′je-a)

SYN: hematophagia. [hemo- + G. phagein, to eat]

hemophagocytosis
hemophagocytosis (he′mo-fag′o-si-to′sis)

The process of engulfment (and usually destruction) of blood cells by the various types of phagocytic cells; used especially with reference to the engulfment of erythrocytes and others of the erythroid series.

hemophil
hemophil, hemophile (he′mo-fil, -fil)

A microorganism growing preferably in media containing blood. [hemo- + G. philos, fond]

hemophilia
hemophilia (he-mo-fil′e-a)

An inherited disorder of blood coagulation characterized by a permanent tendency to hemorrhages, spontaneous or traumatic, because of a defect in the blood coagulating mechanism. [hemo- + G. philos, fond]
h. A [MIM*306700-various] h. due to deficiency of factor VIII; an X-linked recessive condition, occurring almost exclusively in human males and also affecting several breeds of dogs, characterized by prolonged clotting time, decreased formation of thromboplastin, and diminished conversion of prothrombin. SYN: classic h..
h. B [MIM*306900-various] a clotting disorder resembling h. A, caused by hereditary deficiency of factor IX; also seen as an X-linked recessive condition in the Cairn terrier breed of dogs. SYN: Christmas disease.
h. C h. due to deficiency of factor XI; clinically resembles h. A and B but is transmitted as an autosomal dominant inheritance; occurs primarily in persons of Jewish ancestry.
classic h. SYN: h. A.

hemophiliac
hemophiliac (he-mo-fil′e-ak)

A person suffering from hemophilia.

hemophilic
hemophilic (he-mo-fil′ik)

Relating to hemophilia.

hemophilosis
hemophilosis (he-mo-fil-o′sis)

Any disease caused by bacteria of the genus Haemophilus.

hemophobia
hemophobia (he-mo-fo′be-a)

Morbid fear of blood or of bleeding. [hemo- + G. phobos, fear]

hemophoresis
hemophoresis (he′mo-fo-re′sis)

Blood convection or irrigation of tissues. [hemo- + G. phoreo, to bear]

hemophthalmia
hemophthalmia, hemophthalmus (he-mof-thal′me-ah, -mof-thal′mus)

A blood-filled eye. SYN: hematopsia. [hemo- + G. ophthalmos, eye]

hemophthisis
hemophthisis (he-mof′thi-sis, he-mof-thi′sis)

An obsolete term for anemia resulting from abnormal degeneration or destruction, or a deficiency in the formation of red blood cells. [hemo- + G. phthisis, a wasting away]

hemoplastic
hemoplastic (he-mo-plas′tik)

SYN: hemopoietic.

hemoplasty
hemoplasty (he′mo-plas-te)

Formation or elaboration of blood by the hemopoietic tissues. [hemo- + G. plasso, to form]

hemopneumopericardium
hemopneumopericardium (he′mo-noo′mo-par-i-kar′de-um)

Concurrence of blood and air in the pericardium. SYN: pneumohemopericardium. [hemo- + G. pneuma, air, + pericardium]

hemopneumothorax
hemopneumothorax (he′mo-noo-mo-tho′raks)

Accumulation of air and blood in the pleural cavity. SYN: pneumohemothorax. [hemo- + G. pneuma, air, + thorax]

hemopoiesis
hemopoiesis (he′mo-poy-e′sis)

The process of formation and development of the various types of blood cells and other formed elements. SYN: hematogenesis, hematopoiesis, hematosis (1) , hemogenesis, sanguification. [hemo- + G. poiesis, a making]

hemopoietic
hemopoietic (he′mo-poy-et′ik)

Pertaining to or related to the formation of blood cells. SYN: hemafacient, hematogenic (1) , hematogenous, hematoplastic, hematopoietic, hemogenic, hemoplastic, sanguifacient.

hemopoietin
hemopoietin (he-mo-poy′e-tin)

SYN: erythropoietin.

hemoporphyrin
hemoporphyrin (he-mo-por′fi-rin)

SYN: hematoporphyrin.

hemoprecipitin
hemoprecipitin (he′mo-pre-sip′i-tin)

An antibody that combines with and precipitates soluble antigenic material from erythrocytes.

hemoprotein
hemoprotein (he-mo-pro′ten)

Protein linked to a metal-porphyrin compound ( e.g., cytochromes, myoglobin, catalase).

hemoptysis
hemoptysis (he-mop′ti-sis)

Spitting of blood derived from the lungs or bronchial tubes as a result of pulmonary or bronchial hemorrhage. SYN: bronchostaxis. [hemo- + G. ptysis, a spitting]
endemic h. SYN: parasitic h..
parasitic h. the clinical expression of paragonimiasis, marked by a cough and spitting of blood from the lungs. SYN: endemic h..

hemopyelectasis
hemopyelectasis, hemopyelectasia (he′mo-pi′e-lek′ta-sis, -lek-ta′ze-a)

Obsolete term for dilation of the pelvis of the kidney with blood and urine. [hemo- + pyelectasia]

hemorepellant
hemorepellant (he′mo-re-pel′ant)

1. A substance or surface that discourages the adherence of blood. 2. Having such an action.

hemorheology
hemorheology (he′mo-re-ol′o-je)

The science of the flow of blood in relation to the pressures, flow, volumes, and resistances in blood vessels, especially in terms of blood viscosity and red cell deformation in the microcirculation. [hemo- + G. rheos, stream, flow, + logos, study]

hemorrhage
hemorrhage (hem′o-rij)

1. An escape of blood from the intravascular space. 2. To bleed. [G. haimorrhagia, fr. haima, blood, + rhegnymi, to burst forth]
brainstem h. h. into the pons or mesencephalon, often secondary to brainstem distortion by transtentorial herniations due to rapidly expanding intracranial lesions.
cerebral h. h. into the substance of the cerebrum, usually in the region of the internal capsule by the rupture of the lenticulostriate artery. SYN: hematencephalon, intracerebral h..
concealed h. SYN: internal h..
Duret h. small brainstem h. resulting from brainstem distortion secondary to transtentorial herniation.
extradural h. an accumulation of blood between the skull and the dura mater. SYN: epidural hematoma.
gastric h. SYN: gastrorrhagia.
intermediate h. h. that is recurrent.
internal h. bleeding into organs or cavities of the body. SYN: concealed h..
intracerebral h. SYN: cerebral h..
intracranial h. bleeding within the cranial vault; includes cerebral h. and subarachnoid h..
intrapartum h. h. occurring in the course of normal labor and delivery.
intraventricular h. extravasation of blood into the ventricular system of the brain.
nasal h. SYN: epistaxis.
parenchymatous h. bleeding into the substance of an organ.
h. per rhexis h. due to the rupture of a blood vessel.
petechial h. capillary h. into the skin that forms petechiae. SYN: punctate h..
pontine h. h. occurring in the substance of the pons, typically in hypertensive patients.
postpartum h. h. from the birth canal in excess of 500 ml after a vaginal delivery or 1000 mL after a cesarean delivery during the first 24 hours after birth.
primary h. h. immediately after an injury or operation, as distinguished from intermediate or secondary h..
punctate h. SYN: petechial h..
renal h. hematuria, of which the kidney is the source.
secondary h. h. at an interval after an injury or an operation.
serous h. obsolete term for a profuse transudation of plasma through the walls of the capillaries.
splinter hemorrhages tiny longitudinal subungual hemorrhages typically seen in but not diagnostic of bacterial endocarditis, trichinosis, etc.
subarachnoid h. extravasation of blood into the subarachnoid space, often due to aneurysm rupture and usually spreading throughout the cerebrospinal fluid pathways.
subdural h. extravasation of blood between the dural and arachnoidal membranes; acute and chronic forms occur; chronic hematomas may become encapsulated by neomembranes. SYN: subdural hematoma.
subgaleal h. collection of blood beneath the galea aponeurotica.
syringomyelic h. h. into a syringomyelic cavity.

hemorrhagic
hemorrhagic (hem-o-raj′ik)

Relating to or marked by hemorrhage.

hemorrhagins
hemorrhagins (hem-o-raj′inz, -ra′jins)

Cytolysins found in certain venoms and poisonous material from some plants, e.g., rattlesnake venom and ricin; h. cause degeneration and lysis of endothelial cells in capillaries and small vessels, thereby resulting in numerous small hemorrhages in the tissues. [hemorrhage + -in]

hemorrhoid
hemorrhoid (hem′o-royd)

Denoting one of the tumors or varices constituting hemorrhoids.

hemorrhoidal
hemorrhoidal (hem-o-roy′dal)

1. Relating to hemorrhoids. 2. Formerly applied to certain arteries and veins supplying the region of the rectum and anus, currently described by “anal” or “rectal.”

hemorrhoidectomy
hemorrhoidectomy (hem′o-roy-dek′to-me)

Surgical removal of hemorrhoids; usually accomplished by excision of hemorrhoidal tissues by sharp dissection, or by application of elastic ligature at the base of the hemorrhoidal bundles to produce ischemic necrosis and ultimate ablation of the h.. [hemorrhoids + G. ektome, excision]

hemorrhoids
hemorrhoids (hem′o-roydz)

A varicose condition of the external hemorrhoidal veins causing painful swellings at the anus. SYN: piles. [G. haimorrhois, pl. haimorrhoides, veins likely to bleed, fr. haima, blood, + rhoia, a flow]
cutaneous h. hyperplasia of the connective tissue in one or more of the normal radiating folds of the skin immediately surrounding the anus.
external h. dilated veins forming tumors at the outer side of the external sphincter.
internal h. dilated veins beneath the mucous membrane within the sphincter.

hemosalpinx
hemosalpinx (he′mo-sal′pinks)

SYN: hematosalpinx.

hemosialemesis
hemosialemesis (he′mo-si-al-em′e-sis)

Vomiting of blood and saliva. [hemo- + G. sialon, saliva, + emesis, vomiting]

hemosiderin
hemosiderin (he-mo-sid′er-in)

A golden yellow or yellow-brown insoluble protein produced by phagocytic digestion of hematin; found in most tissues, especially in the liver, spleen, and bone marrow, in the form of granules much larger than ferritin molecules (of which they are believed to be aggregates), but with a higher content, as much as 37%, of iron; stains blue with Perl Prussian blue stain. [hemo- + G. sideros, iron, + -in]

hemosiderosis
hemosiderosis (he′mo-sid-er-o′sis)

Accumulation of hemosiderin in tissue, particularly in liver and spleen. See hemochromatosis. [hemosiderin + -osis, condition]
idiopathic pulmonary h. repeated sudden attacks of dyspnea and hemoptysis leading to diffuse pulmonary h., seen most commonly in children; of unknown cause, but some cases may be associated with Goodpasture syndrome. SYN: Ceelen-Gellerstedt syndrome.
nutritional h. a disease that results from ingestion of iron in foodstuffs prepared in iron vessels.

hemospermia
hemospermia (he′mo-sper′me-a)

Presence of blood in the seminal fluid. SYN: hematospermia. [hemo- + G. sperma, seed]
h. spuria h. occurring in the prostatic urethra.
h. vera h. from the seminal vesicles.

hemosporidium
hemosporidium (he′mo-spo-rid′e-um)

A blood parasite of the order Haemosporidia. [hemo- + Mod. L. dim. of G. sporos, seed]

hemosporines
hemosporines (he′mo-spo-renz)

Common term for members of the order Haemosporidia.

hemostasia
hemostasia (he-mo-sta′ze-a)

SYN: hemostasis.

hemostasis
hemostasis (he′mo-sta-sis, he-mos′ta-sis)

1. The arrest of bleeding. 2. The arrest of circulation in a part. 3. Stagnation of blood. SYN: hemostasia. [hemo- + G. stasis, a standing]

hemostat
hemostat (he′mo-stat)

1. Any agent that arrests, chemically or mechanically, the flow of blood from an open vessel. 2. An instrument for arresting hemorrhage by compression of the bleeding vessel.

hemostatic
hemostatic (he-mo-stat′ik)

1. Arresting the flow of blood within the vessels. 2. SYN: antihemorrhagic.

hemostyptic
hemostyptic (he-mo-stip′tik)

SYN: styptic (2) . [hemo- + G. styptikos, astringent]

hemosuccus pancreaticus
hemosuccus pancreaticus

Bleeding into the pancreatic duct, usually as a result of trauma, tumor, inflammation, or pseudoaneurysm associated with pseudocyst.

hemotachogram
hemotachogram (he-mo-ta′cho-gram)

The record produced by hemotachometer. [hemo + tachos + G. gramma, something written]

hemotachometer
hemotachometer (he′mo-ta-kom′e-ter)

An instrument for measuring the rapidity of the flow of blood in the arteries. SYN: hematachometer. [hemo- + G. tachos, swiftness, + metron, measure]

hemotherapy
hemotherapy, hemotherapeutics (he′mo-thar′a-pe, thar-a-pu′tiks)

Treatment of disease by the use of blood or blood derivatives, as in transfusion. SYN: hematherapy.

hemothorax
hemothorax (he-mo-thor′aks)

Blood in the pleural cavity. SYN: hemathorax.

hemotoxic
hemotoxic, hematotoxic, hematoxic (he-mo-tok′sik; he′ma-to-toks′ik, hem′a-; he-ma-toks′ik, hem-a-)

1. Causing blood poisoning. 2. SYN: hemolytic.

hemotoxin
hemotoxin (he-mo-tok′sin)

Any substance that causes destruction of red blood cells, including various hemolysins; usually used with reference to substances of biologic origin, in contrast to chemicals. SYN: hematotoxin, hematoxin.
cobra h. the constituent in cobra venom that hemolyzes the red blood cells of various species.

hemotroph
hemotroph, hemotrophe (hem′o-trof)

The nutritive materials supplied to the embryos of placental mammals through the maternal bloodstream. Cf.:embryotroph, histotroph. [hemo- + G. trophe, food]

hemotropic
hemotropic (he-mo-trop′ik)

Pertaining to the mechanism by which a substance in or on blood cells, especially the erythrocytes, attracts phagocytic cells; the latter change direction and migrate toward the h. cells. SYN: hematotropic. [hemo- + G. tropos, direction (or trope, a turning)]

hemotympanum
hemotympanum (he′mo-tim′pa-num)

The presence of blood in the middle ear. SYN: hematotympanum.

hemozoic
hemozoic (he-mo-zo′ik)

Parasitic in the blood of vertebrates; denoting certain protozoa. SYN: hematozoic.

hemozoon
hemozoon (he-mo-zo′on)

A blood-dwelling parasitic animal such as the trypanosomes or microfilariae of Wuchereria or Brugia. SYN: hematozoon. [hemo- + G. zoon, animal]

HEMPAS
HEMPAS

Abbreviation for hereditary erythroblastic multinuclearity associated with positive acidified serum. See H. cells, under cell.

henbane
henbane (hen′ban)

SYN: hyoscyamus.

Henderson
Henderson

Lawrence J., U.S. biochemist, 1878–1942. See H.-Hasselbalch equation.

Hendersonula toruloidea
Hendersonula toruloidea

SYN: Nattrassia mangiferae.

Henke
Henke

Wilhelm, German anatomist, 1834–1896. See H. space.

Henle
Henle

Friedrich G.J., German anatomist, pathologist, and histologist, 1809–1885. See crypts of H., under crypt, H. ampulla, H. ansa, H. glands, under gland, H. fissures, under fissure, H. layer, H. fiber layer, H. nervous layer, H. loop, H. membrane, H. fenestrated elastic membrane, H. reaction, H. sheath, H. spine, H. tubules, under tubule, H. warts, under wart, Hassall-H. bodies, under body.

henna
henna (hen′a)

The leaves of the Egyptian privet, Lawsonia inermis; used as a cosmetic and hair dye. [Ar. h.]

Hennebert
Hennebert

Camille, Belgian otologist, 1867–1958. See H. sign.

Henoch
Henoch

Eduard H., German pediatrician, 1820–1910. See H. chorea, H. purpura, H.-Schönlein purpura, H.-Schönlein syndrome, Schönlein-H. syndrome.

henpuye
henpuye (hen-poo′ye)

SYN: goundou. [native term on the Gold Coast (Ghana) meaning “dog-nose”]

Henri
Henri

Victor, French 20th-century biochemist. See Michaelis-Menten equation, H.-Michaelis-Menten equation.

Henry
Henry

James Paget, U. S. physiologist, *1914. See H.-Gauer response.

Henry
Henry

Joseph, U.S. physicist, 1797–1878. See Dalton-H. law.

Henry
Henry

William, British chemist, 1774–1836. See H. law.

henry
henry (H) (hen′re)

The unit of electrical inductance, when 1 V is induced by a change in current of 1 A/sec. [Joseph H.]

Henseleit
Henseleit

K., German internist, *1907. See Krebs-H. cycle.

Hensen
Hensen

Victor, German anatomist and physiologist, 1835–1924. See H. canal, H. cell, H. disk, H. duct, H. knot, H. line, H. node, H. stripe.

Hensing
Hensing

Friedrich W., German anatomist, 1719–1745. See H. ligament.

Hepadnaviridae
Hepadnaviridae (he-pa′d′na-vi′ra-da)

A family of lipid-containing icosahedral DNA-containing viruses 42 mm in diameter whose genome consists of a single molecule of noncovalently closed, circular DNA that is partially single-stranded and partially double-stranded; associated with hepatitis in a number of animal species. The principal genus ortho Hepadnavirus is associated with hepatitis B in mammals and the genus Avihepadnavirus with disease in birds; persistant infection is common and is associated with chronic disease and liver cancer. [hepatitis + DNA + virus]

hepar
hepar, gen. hepatis (he′par, he′pah-tis) [TA]

SYN: liver. [L. borrowed fr. G. h., gen. hepatos, the liver]
h. lobatum a fissured liver, from the scars of healed syphilitic gummas.

heparan N-sulfatase
heparan N-sulfatase (hep′a-ran)

An enzyme that participates in the stepwise degradation of heparan sulfate; heparan N-sulfatase hydrolyzes the sulfate moiety attached to the amino group of the glucosamine residue of heparan sulfate; a deficiency of this enzyme is associated with mucopolysaccharidose IIIA (Sanfilippo syndrome A).

heparan sulfate
heparan sulfate

SYN: heparitin sulfate.

heparin
heparin (hep′a-rin)

An anticoagulant principle that is a component of various tissues (especially liver and lung) and mast cells in humans and several mammalian species; its principal and active constituent is a glycosaminoglycan composed of d-glucuronic acid and d-glucosamine, both sulfated, in 1,4-α linkage, of molecular weight 6,000–20,000. In conjunction with a serum protein cofactor (the so-called h. cofactor), h. acts as an antithrombin and an antiprothrombin. Synthetic preparations are commonly used in therapeutic anticoagulation. It also enhances activity of “clearing factors” (lipoprotein lipases). SYN: heparinic acid.
h. eliminase SYN: h. lyase.
h. lyase an enzyme eliminating &Udelta;-4,5-d-glucuronate residues from h. and similar 1,4-linked polyglucuronates. SYN: h. eliminase, heparinase.
h. sodium a mixture of active principles (usually obtained from various tissues of domestic animals) having the properties of prolonging the clotting time of human blood.

heparinase
heparinase (hep′a-rin-as)

SYN: heparin lyase.

heparinemia
heparinemia (hep′a-ri-ne′me-a)

The presence of demonstrable levels of heparin in the circulating blood.

heparinic acid
heparinic acid (hep-a-rin′ik)

SYN: heparin.

heparinize
heparinize (hep′a-rin-iz)

To perform therapeutic administration of heparin.

heparitin sulfate
heparitin sulfate (hep′a-rit-in)

A heteropolysaccharide that has the same repeating disaccharide as heparin but with fewer sulfates and more acetyl groups; accumulates in individuals with certain types of mucopolysaccharidosis. SYN: heparan sulfate.

hepat- hepat-, hepato-

The liver. [G. hepar (hepat-)]

hepatatrophia
hepatatrophia, hepatatrophy (hep′a-ta-tro′fe-a, hep-a-tat′ro-fe)

Atrophy of the liver.

hepatectomy
hepatectomy (hep-a-tek′to-me)

Removal of the liver, whole or in part. [hepat- + G. ektome, excision]

hepatic
hepatic (he-pat′ik)

Relating to the liver. [G. hepatikos]

hepaticodochotomy
hepaticodochotomy (he-pat′i-ko-do-kot′o-me)

Combined hepaticotomy and choledochotomy.

hepaticoduodenostomy
hepaticoduodenostomy (he-pat′i-ko-doo′o-de-nos′to-me)

Establishment of a communication between the hepatic ducts and the duodenum. SYN: hepatoduodenostomy. [hepatico- + duodenostomy]

hepaticoenterostomy
hepaticoenterostomy (he-pat′i-ko-en-ter-os′to-me)

Establishment of a communication between the hepatic ducts and the intestine. SYN: hepatocholangioenterostomy. [hepatico- + enterostomy]

hepaticogastrostomy
hepaticogastrostomy (he-pat′i-ko-gas-tros′to-me)

Establishment of a communication between the hepatic duct and the stomach. [hepatico- + gastrostomy]

hepaticolithotomy
hepaticolithotomy (he-pat′i-ko-li-thot′o-me)

Removal of a stone from a hepatic duct. [hepatico- + G. lithos, stone, + tome, a cutting]

hepaticolithotripsy
hepaticolithotripsy (he-pat′i-ko-lith′o-trip-se)

The crushing or fragmentation of a biliary calculus in a hepatic duct. [hepatico- + G. lithos, stone, + tripsis, a rubbing]

hepaticopulmonary
hepaticopulmonary (he-pat′i-ko-pul′mo-nar-e)

SYN: hepatopneumonic.

hepaticostomy
hepaticostomy (he-pat-i-kos′to-me)

Establishment of an opening into the hepatic duct. [hepatico- + G. stoma, mouth]

hepaticotomy
hepaticotomy (he-pat-i-kot′o-me)

Incision into the hepatic duct. [hepatico- + G. tome, incision]

hepatin
hepatin (hep′a-tin)

SYN: glycogen.

hepatitic
hepatitic (hep-a-tit′ik)

Relating to hepatitis.

hepatitis
hepatitis (hep-a-ti′tis)

Inflammation of the liver, due usually to viral infection but sometimes to toxic agents. [hepat- + -itis] Previously endemic throughout much of the developing world, viral h. now ranks as a major public health problem in industrialized nations. The 3 most common types of viral h. (A, B, and C) afflict millions worldwide. Acute viral h. is characterized by varying degrees of fever, malaise, weakness, anorexia, nausea, and abdominal distress. Hepatocellular damage causes bilirubin retention, often with jaundice, and a rise in serum levels of certain enzymes (particularly transaminases). H. A, caused by an enterovirus, is spread by the fecal-oral route, most often through ingestion of contaminated food or water. The case fatality rate is less than 1%, and recovery is complete. The presence of antibody to h. A virus indicates prior infection, noninfectivity, and immunity to future attacks. H. B, due to a small DNA virus, is transmitted through sexual contact, sharing of needles by IV drug abusers, needlestick injuries among health care workers, and from mother to fetus. The annual incidence in the U.S. is 300,000 cases. The incubation period is 6–24 weeks. Some patients become carriers, and in some an immune response to the virus induces a chronic phase leading to cirrhosis, hepatic failure, and risk of hepatocellular carcinoma. H. B surface antigen (HBsAg) is detectable early in serum; its persistence correlates with chronic infection and infectivity. Core antigen (HBcAg) appears later and also indicates infectivity. H. C is the principal form of transfusion-induced h.; a chronic active form often develops. Acute infection with h. B or C has a higher mortality rate than h. A. Effective vaccines are available for active immunization against h. A and h. B. Interferon-alpha brings about clinical remission in some cases of h. B and h. C. H. D is due to an RNA virus capable of causing disease only in persons previously infected with h. B. H. E, which occurs chiefly in the tropics, resembles h. A in that it is transmitted by the fecal-oral route and does not become chronic or lead to a carrier state, but it has a much higher mortality rate.
h. A SYN: viral h. type A.
acute parenchymatous h. SYN: acute massive liver necrosis.
anicteric h. h. without jaundice.
anicteric virus h. a relatively mild h., without jaundice, due to a virus; the principal physical signs and symptoms are enlargement of the liver, lymph nodes, and often the spleen, together with headache, continuous fatigue, nausea, anorexia, sudden distaste for smoking, abdominal pains, and sometimes mild fever; laboratory tests reveal evidence of h..
h. B SYN: viral h. type B.
h. C SYN: viral h. type C.
cholangiolitic h. h. with inflammatory changes around small bile ducts, producing mainly obstructive jaundice; may be due to viral or bacterial infection ascending biliary tree because of obstruction.
cholestatic h. jaundice with bile stasis in inflamed intrahepatic bile ducts; usually due to toxic effects of a drug.
chronic h. any of several types of h. persisting for more than six months, often progressing to cirrhosis. SYN: chronic active liver disease.
chronic active h. h. with chronic portal inflammation that extends into the parenchyma, with piecemeal necrosis and fibrosis which usually progresses to a coarsely nodular postnecrotic cirrhosis. SYN: juvenile cirrhosis, posthepatitic cirrhosis, subacute h..
chronic interstitial h. obsolete term for cirrhosis of the liver.
chronic persistent h. SYN: chronic persisting h..
chronic persisting h. a form of chronic h. that is usually benign, not progressing to cirrhosis, and usually asymptomatic without physical findings but with continuing abnormalities of tests of liver status. SYN: chronic persistent h..
h. D SYN: viral h. type D.
delta h. SYN: viral h. type D.
drug-induced h. hepatocellular damage produced by a drug.
h. E SYN: viral h. type E.
epidemic h. SYN: viral h. type A.
h. externa SYN: perihepatitis.
h. F a disease caused by an as yet poorly characterized DNA virus.
fulminant h. severe, rapidly progressive loss of hepatic function due to viral infection or other cause of inflammatory destruction of liver tissue.
h. G a disease caused by an RNA virus similar to h. virus.
giant cell h. SYN: neonatal h..
halothane h. hepatocellular damage said to result from the administration of halothane anesthesia.
infectious h. (IH) SYN: viral h. type A.
long incubation h. outdated name for h. B based on the longer incubation period (range 30–180 days, usually 60–90) compared with h. A (15–45 days, mean 30).
lupoid h. jaundice with evidence of liver cell damage and positive antinuclear antibody or LE cell tests, but without evidence of systemic lupus erythematosus; liver biopsies usually show chronic active h. with infiltration by plasma cells, or postnecrotic cirrhosis; serum is negative for h. B antigen. SYN: plasma cell h..
MS-1 h. SYN: viral h. type A.
NANB h. SYN: non-A, non-B h..
NANBNC h. abbreviation for non-A, non-B, non-C h..
neonatal h. h. in the neonatal period presumed to be due to any of a variety of causes, chiefly viral; characterized by direct and indirect bilirubinemia, hepatocellular degeneration, and appearance of multinucleated giant cells; may be difficult to distinguish from biliary atresia, but is more likely to end with recovery, although cirrhosis may develop. SYN: giant cell h..
non–A-E h. an acute h. not caused by any of the identified viral agents A through E.
non-A, non-B h. h. caused by any number of infectious agents not detectable by methods that reveal the presence of h. viruses A and B. SYN: NANB h..
non-A, non-B, non-C h. (NANBNC h.) h. caused by viral organisms other than h. viruses A, B, or C.
peliosis h. a rare condition in which the liver contains very numerous small blood-filled spaces, sometimes lined with endothelium; it may be found incidentally or rupture may cause intraperitoneal hemorrhage.
plasma cell h. SYN: lupoid h..
serum h. (SH) SYN: viral h. type B.
short incubation h. SYN: viral h. type A.
subacute h. SYN: chronic active h..
suppurative h. h. with abscess formation; often amebic in origin.
transfusion h. SYN: viral h. type B.
viral h. 1. h. caused by any one of at least 7 immunologically unrelated viruses: h. A virus, h. B virus, h. C virus, h. D virus, h. E virus, h. F virus, h. G virus; 2. h. caused by a viral infection, including that by Epstein-Barr virus and cytomegalovirus. SYN: virus h..
viral h. type A a virus disease with a short incubation period (usually 15–50 days), caused by h. A virus, a member of the family Picornaviridae, often transmitted by fecal-oral route; may be inapparent, mild, severe, or occasionally fatal and occurs sporadically or in epidemics, commonly in school-age children and young adults; necrosis of periportal liver cells with lymphocytic and plasma cell infiltration is characteristic and jaundice is a common symptom. SYN: epidemic h., h. A, infectious h., MS-1 h., short incubation h., virus A h..
viral h. type B a virus disease with a long incubation period (usually 50–160 days), caused by a h. B virus, a DNA virus and member of the family Hepadnaviridae, usually transmitted by injection of infected blood or blood derivatives or by use of contaminated needles, lancets, or other instruments; clinically and pathologically similar to viral h. type A, but there is no cross-protective immunity; HB_sAg is found in the serum and the h. delta virus occurs in some patients. SYN: h. B, serum h., transfusion h., virus B h..
viral h. type C (NANB); principal cause of non-A, non-B posttransfusion h. caused by an RNA virus that is classified with the Flaviviridae family. The incubation period is 6–8 weeks with about 75% of infections subclinical and giving rise to chronic persistent infection. A high percentage of these develop chronic liver disease leading to cirrhosis and possible hepatocellular carcinoma. SYN: h. C, virus C h..
viral h. type D acute or chronic h. caused by a satellite virus, the h. deltavirus, a defective RNA virus requiring HBV for replication since it uses HB_sAg as its own coat. The acute type occurs in two forms: 1) coinfection, the simultaneous occurrence of h. B virus and h. delta virus infections, which usually is self-limiting; 2) superinfection, the appearance of h. delta virus infection in a h. B virus carrier, which often leads to chronic h. The chronic type appears to be more severe than other types of viral h.. SYN: delta h., h. D.
viral h. type E h. caused by a nonenveloped, single-stranded, positive-sense RNA virus 27–34 nm in diameter, unrelated to other h. and belonging to the family Caliciviridae; it is the principal cause of enterically transmitted, waterborne, epidemic NANB h. occurring primarily in Asia, Africa and South America. SYN: h. E.
virus h. SYN: viral h..
virus A h. SYN: viral h. type A.
virus B h. SYN: viral h. type B.
virus C h. SYN: viral h. type C.

hepatization
hepatization (hep′a-ti-za′shun)

Conversion of a loose tissue into a firm mass like the substance of the liver macroscopically, denoting especially such a change in the lungs in the consolidation of pneumonia.
gray h. the second stage of h. in pneumonia, when the exudate is beginning to degenerate prior to breaking down; the color is a yellowish gray or mottled.
red h. the first stage of h. in which the exudate is blood-stained.
yellow h. the final stage of h. in which the exudate is becoming purulent.

hepato- hepato-

See hepat-.

hepatoblastoma
hepatoblastoma (hep′a-to-blas-to′ma)

A malignant neoplasm occurring in young children, primarily in the liver, composed of tissue resembling embryonal or fetal hepatic epithelium, or mixed epithelial and mesenchymal tissues.

hepatocarcinoma
hepatocarcinoma (hep′a-to-kar-si-no′ma)

SYN: hepatocellular carcinoma.

hepatocele
hepatocele (hep′a-to-sel, he-pat′o-sel)

Protrusion of part of the liver through the abdominal wall or the diaphragm. [hepato- + G. kele, hernia]

hepatocholangioenterostomy
hepatocholangioenterostomy (hep′a-to-ko-lan′je-o-en-ter-os′to-me)

SYN: hepaticoenterostomy. [hepato- + G. chole, bile, + angeion, vessel, + enteron, intestine, + stoma, mouth]

hepatocholangiojejunostomy
hepatocholangiojejunostomy (hep′a-to-ko-lan′je-o-je-joo-nos′to-me)

Union of the hepatic duct to the jejunum. [hepato- + G. chole, bile, + angeion, vessel, + jejunostomy]

hepatocholangiostomy
hepatocholangiostomy (hep′a-to-ko-lan-je-os′to-me)

Creation of an opening into the common bile duct to establish drainage.

hepatocholangitis
hepatocholangitis (hep′a-to-ko-lan-ji′tis)

Inflammation of the liver and biliary tree.

hepatocuprein
hepatocuprein (hep′a-to-koo′pre-in)

SYN: cytocuprein.

hepatocystic
hepatocystic (hep′a-to-sis′tik)

Relating to the gallbladder, or to both liver and gallbladder. [hepato- + G. kystis, bladder]

Hepatocystis
Hepatocystis (hep′a-to-sis′tis)

A genus of blood-parasitizing hemosporines (family Plasmodiidae) with gametocytes in red cells and cystlike exoerythrocytic schizonts in the liver parenchyma; parasitic in Old World primates, bats, and squirrels, but not in domestic animals or in the western hemisphere. The species H. kochi, a common parasite of African baboons and other monkeys, is transmitted by the biting midge, Culicoides. [hepato- + G. kystis, bladder]

hepatocyte
hepatocyte (hep′a-to-sit)

A parenchymal liver cell.

hepatoduodenostomy
hepatoduodenostomy (hep′a-to-doo-o-de-nos′to-me)

SYN: hepaticoduodenostomy.

hepatodysentery
hepatodysentery (hep′a-to-dis′en-ter-e)

Dysentery associated with liver disease.

hepatoenteric
hepatoenteric (hep′a-to-en-ter′ik)

Relating to the liver and the intestine. [hepato- + G. enteron, intestine]

hepatofugal
hepatofugal (hep′a-to-fu′gal)

Away from the liver, usually referring to portal blood flow.

hepatogastric
hepatogastric (hep′a-to-gas′trik)

Relating to the liver and the stomach.

hepatogenic
hepatogenic, hepatogenous (hep-a-to-jen′ik, -toj′en-us)

Of hepatic origin; formed in the liver.

hepatography
hepatography (hep-a-tog′ra-fe)

Radiography of the liver. [hepato- + G. graphe, a writing]

hepatohemia
hepatohemia (hep′a-to-he′me-a)

Rarely used term for congestion of the liver. [hepato- + G. haima, blood]

hepatoid
hepatoid (hep′a-toyd)

Resembling or like the liver. [hepato- + G. eidos, resemblance]

hepatojugularometer
hepatojugularometer (hep′a-to-jug′u-la-rom′e-ter)

An apparatus for the quantitative control and measurement of the pressure and force applied over the liver to test the hepatojugular reflux. [hepato- + L. jugulum, throat, + G. metron, measure]

hepatolienography
hepatolienography (hep′a-to-li-en-og′ra-fe)

SYN: hepatosplenography. [hepato- + L. lien, spleen, + G. graphe, a writing]

hepatolienomegaly
hepatolienomegaly (hep′a-to-li′e-no-meg′a-le)

SYN: hepatosplenomegaly.

hepatolith
hepatolith (hep′a-to-lith)

A concretion in the liver. [hepato- + G. lithos, stone]

hepatolithectomy
hepatolithectomy (hep′a-to-li-thek′to-me)

Removal of a calculus from the liver. [hepato- + G. lithos, stone, + ektome, excision]

hepatolithiasis
hepatolithiasis (hep′a-to-li-thi′a-sis)

Presence of calculi in the liver. [hepato- + G. lithiasis, presence of a calculus]

hepatologist
hepatologist (hep-a-tol′o-jist)

A specialist in hepatology.

hepatology
hepatology (hep-a-tol′o-je)

The branch of medicine concerned with diseases of the liver. [hepato- + G. logos, study]

hepatolysin
hepatolysin (hep-a-tol′i-sin)

A cytolysin that destroys parenchymal cells of the liver.

hepatoma
hepatoma (hep-a-to′ma)

See malignant h.. [hepato- + G. -oma, tumor]
malignant h. SYN: hepatocellular carcinoma.

hepatomalacia
hepatomalacia (hep′a-to-ma-la′she-a)

Softening of the liver. [hepato- + G. malakia, softening]

hepatomegaly
hepatomegaly, hepatomegalia (hep′a-to-meg′a-le, -me-ga′le-a)

Enlargement of the liver. [hepato- + G. megas, large]

hepatomelanosis
hepatomelanosis (hep′a-to-mel′a-no′sis)

Heavy pigmentation of the liver. [hepato- + G. melas, black, + -osis, condition]

hepatomphalocele
hepatomphalocele (hep′a-tom-fal′o-sel, hep-a-tom′fa-lo-sel)

Umbilical hernia with involvement of the liver. SYN: hepatomphalos. [hepato- + omphalocele]

hepatomphalos
hepatomphalos (hep-a-tom′fa-los)

SYN: hepatomphalocele.

hepatonecrosis
hepatonecrosis (hep′a-to-ne-kro′sis)

Death of liver cells.

hepatonephric
hepatonephric (hep′a-to-nef′rik)

SYN: hepatorenal.

hepatonephromegaly
hepatonephromegaly (hep′a-to-nef′ro-meg′a-le)

Enlargement of both liver and kidney or kidneys. [hepato- + G. nephros, kidney, + megas, great]

hepatopathic
hepatopathic (hep′a-to-path′ik)

Damaging the liver.

hepatopathy
hepatopathy (hep-a-top′a-the)

Disease of the liver. [hepato- + G. pathos, suffering]

hepatoperitonitis
hepatoperitonitis (hep′a-to-par′i-to-ni′tis)

SYN: perihepatitis.

hepatopetal
hepatopetal (hep′a-to-pet′al)

Toward the liver, usually referring to the normal direction of portal blood flow.

hepatopexy
hepatopexy (hep′a-to-pek-se)

Anchoring of the liver to the abdominal wall. [hepato- + G. pexis, fixation]

hepatophyma
hepatophyma (hep′a-to-fi′ma)

Rounded or nodular tumor of the liver. [hepato- + G. phyma, tumor]

hepatopneumonic
hepatopneumonic (hep′a-to-noo-mon′ik)

Relating to the liver and the lungs. SYN: hepaticopulmonary, hepatopulmonary. [hepato- + G. pneumonikos, pulmonary]

hepatoportal
hepatoportal (hep′a-to-por′tal)

Relating to the portal system of the liver.

hepatoptosis
hepatoptosis (hep′a-top-to′sis, to-to′sis)

A downward displacement of the liver. SYN: wandering liver. [hepato- + G. ptosis, a falling]

hepatopulmonary
hepatopulmonary (hep′a-to-pul′mo-nar′e)

SYN: hepatopneumonic.

hepatorenal
hepatorenal (hep-a-to-re′nal)

Relating to the liver and the kidney. SYN: hepatonephric. [hepato- + L. renalis, renal, fr. renes, kidneys]

hepatorrhagia
hepatorrhagia (hep′a-to-ra′je-a)

Hemorrhage into or from the liver. [hepato- + G. rhegnymi, to burst forth]

hepatorrhaphy
hepatorrhaphy (hep-a-tor′a-fe)

Suture of a wound of the liver. [hepato- + G. rhaphe, a suture]

hepatorrhexis
hepatorrhexis (hep′a-to-rek′sis)

Rupture of the liver. [hepato- + G. rhexis, rupture]

hepatoscopy
hepatoscopy (hep-a-tos′ko-pe)

Examination of the liver. [hepato- + G. skopeo, to examine]

hepatosplenitis
hepatosplenitis (hep′a-to-sple-ni′tis)

Inflammation of the liver and spleen.

hepatosplenography
hepatosplenography (hep′a-to-sple-nog′ra-fe)

The use of a contrast medium to outline or depict the liver and spleen radiographically. SYN: hepatolienography.

hepatosplenomegaly
hepatosplenomegaly (hep′a-to-sple-no-meg′a-le)

Enlargement of the liver and spleen. SYN: hepatolienomegaly. [hepato- + G. splen, spleen, + megas, large]

hepatosplenopathy
hepatosplenopathy (hep′a-to-sple-nop′a-the)

Disease of the liver and spleen.

hepatostomy
hepatostomy (hep-a-tos′to-me)

Establishment of a fissure into the liver. [hepato- + G. stoma, mouth]

hepatotherapy
hepatotherapy (hep′a-to-thar′a-pe)

Rarely used term for: 1. Treatment of disease of the liver. 2. Therapeutic use of liver extract or of the raw substance of the liver.

hepatotomy
hepatotomy (hep-a-tot′o-me)

Incision into the liver. [hepato- + G. tome, incision]

hepatotoxemia
hepatotoxemia (hep′a-to-tok-se′me-a)

Autointoxication assumed to be due to improper functioning of the liver. [hepato- + G. toxikon, poison, + haima, blood]

hepatotoxic
hepatotoxic (hep′a-to-tok′sik)

Relating to an agent that damages the liver, or pertaining to any such action.

hepatotoxicity
hepatotoxicity

The capacity of a drug, chemical, or other exposure to produce injury to the liver. Agents with recognized h. include carbon tetrachloride, alcohol, dantrolene sodium, valproic acid, isonicotinic acid hydrazide.

hepatotoxin
hepatotoxin (hep′a-to-tok′sin)

A toxin that is destructive to parenchymal cells of the liver.

Hepatozoon
Hepatozoon (hep′a-to-zo′on)

A genus of coccidian parasites (family Haemogregarinidae), in which schizogony occurs in the visceral organs, gametogony in the leukocytes or erythrocytes of vertebrate animals, and sporogony in certain ticks and other blood-sucking invertebrates. H. canis occurs in dogs, cats, jackals, and hyenas, but is most pathogenic in dogs, in which it may cause serious disease and death; other species have been described from rats, mice, rabbits, and squirrels. [hepato- + G. zoon, animal]

HEPES
HEPES

A compound lacking in pharmacologic effects and widely used as a biological buffer in in vitro experiments.

hepta- hepta-

Prefix denoting seven. Cf.:septi-, sept-. [G. hepta]

heptachlor
heptachlor (hep′ta-klor)

A chlorinated hydrocarbon insecticide for control of cotton boll weevil. It is a poison which may enter the body via skin contamination, inhalation or ingestion. Because of human toxicity concerns, this chemical has only limited application.

heptad
heptad (hep′tad)

A septivalent chemical element or radical.

heptanal
heptanal (hep′ta-nal)

Obtained from the ricinoleic acid of castor oil by chemical means; used in the manufacture of ethyl oenanthate, a constituent of many artificial essences (flavors). SYN: enanthal, oenanthal.

heptapeptide
heptapeptide (hep-ta-pep′tid)

A peptide containing seven amino acids.

heptose
heptose (hep′tos)

A sugar with seven carbon atoms in its molecule; e.g., sedoheptulose.

heptulose
heptulose (hep′too-los)

SYN: ketoheptose.

Herbert
Herbert

H., English ophthalmic surgeon, 1865–1942.

herbivorous
herbivorous (her-biv′o-rus)

Feeding on plants. [L. herba, herb, + voro, to devour]

herd
herd (herd)

A group of people or animals in a given area. [O.E. heord]

hereditary
hereditary (he-red′i-ter-e)

Transmissible from parent to offspring by information encoded in the parental germ cell. [L. hereditarius; fr. heres (hered-), an heir]

heredity
heredity (he-red′i-te)

1. The transmission of characters from parent to offspring by information encoded in the parental germ cells. 2. Genealogy. [L. hereditas, inheritance, fr. heres (hered-), heir]

heredo- heredo-

Heredity. [L. heres, an heir]

heredopathia atactica polyneuritiformis
heredopathia atactica polyneuritiformis (her′e-do-path′e-a a-tak′ti-ka pol′e-noo-ri-ti-for′mis)

SYN: Refsum disease.

heredotaxia
heredotaxia

SYN: Friedreich ataxia.

Herelle
Herelle

Felix H. See d'H..

Herellea
Herellea (he-rel′e-a)

A bacterial generic name which has been officially rejected because its type species, H. vaginicola, is a member of the genus Acinetobacter.

Hering
Hering

Heinrich Ewald, German physiologist, 1866–1948. See sinus nerve of H., H.-Breuer reflex, Traube-H. curves, under curve.

Hering
Hering

Karl E.K., German physiologist, 1834–1918. See H. test, H. theory of color vision, canal of H., Traube-H. curves, under curve, Traube-H. waves, under wave, Semon-H. theory.

heritability
heritability (her′i-ta-bil′i-te)

1. In psychometrics, a statistical term used to denote the extent of variance of an individual's total score or response that is attributable to a presumed genetic component, in contrast to an acquired component. 2. In genetics, a statistical term used to denote the proportion of phenotypic variance due to variance in genotypes that is genetically determined, denoted by the traditional symbol h². [see heredity]
h. in the broad sense the proportion of the total phenotypic variance that can be ascribed to genetic factors of any kind (additive, those due to dominance effects, epistasis and hypostasis, and interactions of all kinds).
h. in the narrow sense the proportion of the total phenotypic variance that can be ascribed to additive genetic variance alone. It reflects the similarity between parent and offspring, and is related to the commercial breeding value.

heritage
heritage (her′i-tij)

The total of all the inherited characters. [O. Fr.]

Herlitz
Herlitz

Gillis, Swedish pediatrician, *1902. See H. syndrome.

Herman Herman

E., 20th century U.S. histologist. See Padykula-H. stain for myosin ATPase. See Padykula-H. stain for myosin ATPase.

Hermann
Hermann

Friedrich, German anatomist, 1859–1920. See H. fixative.

Hermansky
Hermansky

Frantisek, 20th century Czech physician. See H.-Pudlak syndrome.

hermaphrodism
hermaphrodism (her-maf′ro-dizm)

SYN: hermaphroditism.

hermaphrodite
hermaphrodite (her-maf′ro-dit)

A person with hermaphroditism. [G. Hermaphroditos, the son of Hermes, Mercury, + Aphrodite, Venus]

hermaphroditism
hermaphroditism (her-maf′ro-dit-izm)

The presence in one individual of both ovarian and testicular tissue; i.e., true h.. SYN: hermaphrodism.
adrenal h. altered appearance of the genitalia due to disorders of adrenocortical function, most often female virilization; not an example of true h..
bilateral h. true h. with an ovotestis on both sides.
dimidiate h. SYN: lateral h..
false h. SYN: pseudohermaphroditism.
female h. ambiguity of reproductive organs so that the sex of the individual is neither exclusively male or female, but predominantly female h. in which only ovaries are present.
lateral h. a form in which a testis is present on one side and an ovary on the other. SYN: dimidiate h..
male h. more correctly designated as male pseudohermaphroditism, as the term is commonly used; however, it may designate an instance of true h. in which overt bodily characteristics are predominantly male h. in which only testes are present.
transverse h. pseudohermaphroditism in which the external genitalia are characteristic of one sex and the gonads are characteristic of the other sex.
true h. h. in which both ovarian and testicular tissue are present. Somatic characteristics of both sexes are present; also called true intersex.
unilateral h. h. in which the doubling of sex characteristics occurs on one side only: ovotestis on one side and either ovary or testis on the other.

hermetic
hermetic (her-met′ik)

Airtight; denoting a vessel closed or sealed in such a way that air can neither enter it nor issue from it.

hernia
hernia (her′ne-a)

Protrusion of a part or structure through the tissues normally containing it. SYN: rupture (1) . [L. rupture]
abdominal h. a h. protruding through or into any part of the abdominal wall. SYN: laparocele.
Barth h. a loop of intestine between a persistent vitelline duct and the abdominal wall.
Béclard h. a h. through the opening for the saphenous vein.
bilocular femoral h. SYN: Cooper h..
h. of the broad ligament of the uterus a coil of intestine contained in a pouch projecting into the substance of the broad ligament.
cecal h. a h. containing cecum.
cerebral h. protrusion of brain substance through a defect in the skull.
Cloquet h. a femoral h. perforating the aponeurosis of the pectineus and insinuating itself between this aponeurosis and the muscle, lying therefore behind the femoral vessels.
complete h. an indirect inguinal h. in which the contents extend into the tunica vaginalis.
concealed h. a h. not found on inspection or palpation.
congenital diaphragmatic h. 1. absence of the left pleuroperitoneal membrane; 2. SYN: Morgagni foramen h..
Cooper h. a femoral h. with two sacs, the first being in the femoral canal, and the second passing through a defect in the superficial fascia and appearing immediately beneath the skin. SYN: bilocular femoral h., Hey h..
crural h. SYN: femoral h..
diaphragmatic h. protrusion of abdominal contents into the chest through a weakness in the respiratory diaphragm; a common type is the hiatal h..
direct inguinal h. inguinal h..
double loop h. SYN: “w” h..
dry h. a h. with adherent sac and contents.
duodenojejunal h. a h. in the subperitoneal tissues. SYN: retroperitoneal h., Treitz h..
h. en bissac SYN: properitoneal inguinal h..
epigastric h. h. through the linea alba above the navel.
extrasaccular h. SYN: sliding h..
fascial h. a bulging of muscle through a defect in its fascia.
fat h. a h. in which the tissue protruding out of its normal location is composed only of fat.
fatty h. SYN: pannicular h..
femoral h. h. through the femoral ring. SYN: crural h., femorocele.
foramen of Bochdalek h. SYN: Morgagni foramen h..
gastroesophageal h. a hiatal h. into the thorax.
gluteal h. SYN: sciatic h..
Hesselbach h. h. with diverticula through the cribriform fascia, presenting a lobular outline.
Hey h. SYN: Cooper h..
hiatal h., hiatus h. h. of a part of the stomach through the esophageal hiatus of the diaphragm; they are classified as sliding (esophagogastric junction above the diaphragm) or paraesophageal (esophagogastric junction below the diaphragm).
Holthouse h. inguinal h. with extension of the loop of intestine along Poupart ligament.
iliacosubfascial h. a h. the sac of which passes through the iliac fascia and lies in the iliac fossa in contact with the iliacus muscle.
incarcerated h. SYN: irreducible h..
incisional h. h. occurring through a surgical incision or scar.
indirect inguinal h. inguinal h..
infantile h. a h. in which an intestinal loop descends behind the tunica vaginalis, having, therefore, three peritoneal layers in front of it.
inguinal h. a h. at the inguinal region: direct inguinal h. involves the abdominal wall between the deep epigastric artery and the edge of the rectus muscle; indirect inguinal h. involves the internal inguinal ring and passes into the inguinal canal.
inguinocrural h., inguinofemoral h. a bilocular or double h., both inguinal and femoral.
inguinolabial h. an inguinal h. descending into the labium.
inguinoscrotal h. an inguinal h. descending into the scrotum.
inguinosuperficial h. an inguinal h. that has turned cephalad away from the scrotum and lies subcutaneously on the abdominal wall.
internal h. protrusion of an intraperitoneal viscus into a compartment or under a constricting band within the abdominal cavity.
intersigmoid h. a h. into the intersigmoid fossa on the under surface of the root of the mesosigmoid near the inner border of the psoas magnus muscle.
interstitial h. a h. in which the protrusion is between any two of the layers of the abdominal wall.
intraepiploic h. a coil of intestine incarcerated in an omental sac.
intrailiac h. an interstitial h. projecting from the internal inguinal ring.
intrapelvic h. an interstitial h. projecting into the pelvis from the internal inguinal ring.
irreducible h. a h. that cannot be reduced without operation. SYN: incarcerated h..
ischiatic h. a h. through the sacrosciatic foramen.
Krönlein h. SYN: properitoneal inguinal h..
labial h. h. through the canal of Nuck.
lateral ventral h. SYN: spigelian h..
Laugier h. a h. passing through an opening in the lacunar ligament.
levator h. SYN: perineal h..
Littré h. 1. SYN: parietal h.. 2. h. of Meckel diverticulum.
lumbar h. a h. between the last rib and the iliac crest where the aponeurosis of the transversus muscle is covered only by the latissimus dorsi.
Malgaigne h. infantile inguinal h. prior to the descent of the testis.
meningeal h. herniation of meninges through a spina bifida or cranioschesis.
mesenteric h. h. through a hole in the mesentery.
Morgagni foramen h. a congenital anterior, retrosternal h. of abdominal contents, most often only omentum but occasionally stomach, usually through the right retrosternal Morgagni foramen, through which the internal mammary artery passes to become the superior epigastric artery; often asymptomatic. SYN: congenital diaphragmatic h. (2) , foramen of Bochdalek h., parasternal h., retrosternal h..
obturator h. h. through the obturator foramen.
orbital h. displacement of orbital fat through a defect in the orbital septum or Tenon capsule into the subcutaneous tissues of the eyelid or subconjunctivally.
pannicular h. the escape of subcutaneous fat through a gap in a fascia or an aponeurosis. SYN: fatty h..
pantaloon h. an inguinal h. that involves both an indirect and a direct component.
paraduodenal h. a type of internal h., resulting from abnormal or incomplete midgut rotation, which involves one of several paraduodenal spaces.
paraesophageal h. a h. through or adjacent to the esophageal hiatus of the diaphragm in which the esophagogastric junction remains below the diaphragm and the stomach rolls up into the chest.
parahiatal h. a h. through the diaphragm that occurs at a point separate from the esophageal hiatus.
paraperitoneal h. a vesical h. in which only a part of the protruded organ is covered by the peritoneum of the sac.
parasaccular h. SYN: sliding h..
parasternal h. SYN: Morgagni foramen h..
parietal h. a h. in which only a portion of the wall of the intestine is engaged. SYN: Littré h. (1) , partial enterocele, Richter h..
perineal h. a h. protruding through the pelvic diaphragm. SYN: levator h., pudendal h..
Petit h. lumbar h., occurring in Petit triangle.
posterior vaginal h. downward displacement of Douglas pouch.
properitoneal inguinal h. a complicated h. having a double sac, one part in the inguinal canal, the other projecting from the internal inguinal ring in the subperitoneal tissues. SYN: h. en bissac, Krönlein h..
pudendal h. SYN: perineal h..
reducible h. a h. in which the contents of the sac can be returned to their normal location.
retrograde h. a double loop h. the central loop of which lies in the abdominal cavity.
retroperitoneal h. SYN: duodenojejunal h..
retropubic h. a h. projecting downward, in the subperitoneal tissues, from the internal inguinal ring.
retrosternal h. SYN: Morgagni foramen h..
Richter h. SYN: parietal h..
Rokitansky h. a separation of the muscular fibers of the bowel allowing protrusion of a sac of the mucous membrane.
sciatic h. protrusion of intestine through the great sacrosciatic foramen. SYN: gluteal h., ischiocele.
scrotal h. complete inguinal h., located in the scrotum.
sliding h. a h. in which an abdominal viscus forms part of the sac. SYN: extrasaccular h., parasaccular h., slipped h..
sliding esophageal hiatal h. displacement of the cardioesophageal junction and the stomach through the esophageal hiatus into the mediastinum. SYN: sliding hiatal h..
sliding hiatal h. SYN: sliding esophageal hiatal h..
slipped h. SYN: sliding h..
spigelian h. abdominal h. through the semilunar line. SYN: lateral ventral h..
strangulated h. an irreducible h. in which the circulation is arrested; gangrene occurs unless relief is prompt.
synovial h. protrusion of a fold of the stratum synoviale through a rent in the stratum fibrosum of a joint capsule.
Treitz h. SYN: duodenojejunal h..
umbilical h. a h. in which bowel or omentum protrudes through the abdominal wall under the skin at the umbilicus. SEE ALSO: omphalocele. SYN: exomphalos (2) , exumbilication (2) .
h. uteri inguinale SYN: persistent müllerian duct syndrome.
Velpeau h. femoral h. in which the intestine is in front of the blood vessels.
ventral h. an abdominal incisional h..
vesicle h. protrusion of a segment of the bladder through the abdominal wall or into the inguinal canal and into the scrotum.
vitreous h. prolapse of the vitreous humor into the anterior chamber; may follow removal or displacement of the lens from the lenticular space.
“w” h. the presence of two loops of intestine in a hernial sac. SYN: double loop h..

hernial
hernial (her′ne-al)

Relating to hernia.

herniated
herniated (her′ne-a-ted)

Denoting any structure protruded through a hernial opening.

herniation
herniation (her-ne-a′shun)

Protrusion of an anatomic structure ( e.g., intervertebral disk) from its normal anatomic position.
caudal transtentorial h. displacement of medial temporal structures through the incisura, with or without rostrocaudal brainstem shift. SYN: uncal h..
cingulate h. displacement of the cingulate gyrus beneath the falx.
contained disk h. herniated disk material that remains covered by a thin layer of posterior annulus fibrosus or posterior longitudinal ligament; a disk protrusion is an example of a contained disk h..
disk h. extension of disk material beyond the posterior annulus fibrosus and posterior longitudinal ligament and into the spinal canal.
foraminal h. displacement of cerebellar tonsils through the foramen magnum.
noncontained disk h. herniated disk material that comes directly in contact with the anterior epidural space through a complete defect in the posterior annulus fibrosus and posterior longitudinal ligament; of two main types: (1) extrusions, herniated material that is in continuity with the disk space, but extends completely into the epidural space and (2) sequestered, material that has lost continuity with the disk space and becomes a free fragment in the epidural space.
rostral transtentorial h. displacement of anterior cerebellar structures through the incisura, with or without caudorostral brainstem shift.
sphenoidal h. displacement of ventral frontal lobar tissue over the sphenoid ridge.
subfalcial h. h. beneath the falx cerebri; usually of the cingulate gyrus.
tonsillar h. h. of the cerebellar tonsils through the foramen magnum.
transtentorial h. h. into the incisura, either from above (rostral transtentorial h.) or below (caudal transtentorial h.).
uncal h. SYN: caudal transtentorial h..

hernio- hernio-

A hernia. [L. hernia, rupture]

hernioenterotomy
hernioenterotomy (her′ne-o-en-ter-ot′o-me)

Incision of the intestine following the reduction of a hernia.

herniography
herniography (her-ne-og′ra-fe)

Radiographic examination of a hernia following injection of a contrast medium into the hernial sac. [hernia + G. grapho, to write]

hernioid
hernioid (her′ne-oyd)

Resembling hernia. [hernio- + G. eidos, resemblance]

herniolaparotomy
herniolaparotomy (her′ne-o-lap-a-rot′o-me)

Laparotomy for correction of hernia.

herniopuncture
herniopuncture (her′ne-o-punk′choor)

Insertion of a hollow needle into a hernia in order to reduce the size of the tumor by withdrawing gas or liquid.

herniorrhaphy
herniorrhaphy (her′ne-or′a-fe)

Surgical repair of a hernia. [hernio- + G. rhaphe, a seam]
Bassini h. an operation for an indirect inguinal hernia repair; after reduction of the hernia, the sac is twisted, ligated, and cut off, then a new inguinal floor is made by uniting the edge of the internal oblique muscle to the inguinal ligament, placing on this the cord, and covering the latter by the external oblique muscle. SYN: Bassini operation.

herniotome
herniotome (her′ne-o-tom)

SYN: hernia knife.
Cooper h. a slender bistoury with short cutting edge for dividing the constricting tissues at the neck of a hernial sac.

herniotomy
herniotomy (her-ne-ot′o-me)

Surgical division of the constriction or strangulation of a hernia, often followed by herniorrhaphy. [hernio- + G. tome, a cutting]
Petit h. h. without incision into the sac.

heroic
heroic (he-ro′ik)

Denoting an aggressive, daring procedure in a dangerously ill patient which in itself may endanger the patient but which also has a possibility of being successful, whereas lesser action would result in failure. [G. heroikos, pertaining to a hero]

heroin
heroin (H) (her′o-in)

An alkaloid, C₁₇H₁₇(OC₂H₃O)₂ON, prepared from morphine by acetylation; rapidly metabolized to morphine in the body; formerly used for the relief of cough. Except for research, its use in the United States is prohibited by federal law because of its potential for abuse. SYN: diacetylmorphine. [trade name (it was marketed as the “heroine” of analgesic drugs)]

Herophilus Herophilus

Greek physician and anatomist of the Alexandrian school, circa 300 B.C. See torcular herophili.

herpangina
herpangina (her-pan′ji-na, herp-an-ji′na)

A disease caused by types of Coxsackievirus and marked by vesiculopapular lesions about 1–2 mm in diameter that are present around the fauces and soon break down to form grayish yellow ulcers; accompanied by sudden onset of fever, loss of appetite, dysphagia, sore throat, and sometimes abdominal pain, nausea, and vomiting. [G. herpes, vesicular eruption, + L. angina, quinsy, fr. ango, to strangle]

herpes
herpes (her′pez)

An inflammatory skin disease caused by h. simplex virus or varicella-zoster virus; an eruption of groups of deep-seated vesicles on erythematous bases. SYN: serpigo (2) . [G. h., a spreading skin eruption, shingles, fr. herpo, to creep]
h. catarrhalis SYN: h. simplex.
h. corneae SYN: herpetic keratitis.
h. digitalis h. simplex infection of the finger.
h. facialis SYN: h. simplex.
h. febrilis SYN: h. simplex.
h. generalisatus generalized h. simplex virus infection.
h. genitalis, genital h. h. simplex infection on the genitals, most commonly h. simplex-2 virus.
h. gestationis a polymorphous, bullous eruption, more common on the extremities and abdomen than on the upper trunk, with the appearance of pemphigoid or dermatitis herpetiformis; beginning in the second or third trimester, flaring about the time of delivery and subsequently resolving; usually recurrent during subsequent pregnancy. Linear C3 is shown in the epidermal basement membrane by direct immunofluorescence. Not caused by viral infection.
h. gladiatorum h. simplex infection associated with trauma to cutaneous tissue.
h. labialis SYN: h. simplex.
neonatal h. h. simplex virus type 1 or 2 infection transmitted from the mother to the newborn infant, often during passage through an infected birth canal; severity varies from mild to fatal generalized infection, the latter especially with primary maternal genital h..
h. progenitalis genital h. infection caused by h. simplex virus.
h. simplex a variety of infections caused by herpesvirus types 1 and 2; type 1 infections are marked most commonly by the eruption of one or more groups of vesicles on the vermilion border of the lips or at the external nares, type 2 by such lesions on the genitalia; both types often are recrudescent and reappear during other febrile illnesses or even physiologic states such as menstruation. The viruses frequently become latent and may not be expressed for years. SYN: h. catarrhalis, h. facialis, h. febrilis, h. labialis, Simplexvirus.
traumatic h. h. simplex infection at the site of trauma or of a burn, sometimes accompanied by temperature elevation and malaise.
h. whitlow h. simplex inflammation at base of fingernail.
h. zoster an infection caused by a herpesvirus (varicella-zoster virus), characterized by an eruption of groups of vesicles on one side of the body following the course of a nerve due to inflammation of ganglia and dorsal nerve roots resulting from activation of the virus, which in many instances has remained latent for years following a primary chickenpox infection; the condition is self-limited but may be accompanied by or followed by severe postherpetic pain. SEE ALSO: varicella. SYN: zona (2) [TA] , shingles, zoster.
h. zoster ophthalmicus a herpetic involvement of the ophthalmic branch of the trigeminal nerve, which may lead to corneal ulceration.
h. zoster oticus a painful varicella virus infection presenting with a vesicular eruption on the pinna, with or without facial nerve paralysis. SYN: geniculate zoster, Ramsay Hunt syndrome (2) .
h. zoster varicellosus h. zoster associated with disseminated varicelliform lesions.

Herpesviridae
Herpesviridae (her′pes-vir′i-de)

A heterogeneous family of morphologically similar viruses, all of which contain double-stranded DNA and which infect man and a wide variety of other vertebrates. Infections produce type A inclusion bodies; in many instances, infection may remain latent for many years, even in the presence of specific circulating antibodies. Virions are enveloped, ether-sensitive, and vary up to 200 nm in diameter; the nucleocapsids are 100 nm in diameter and of icosahedral symmetry, with 162 capsomeres. The family is subdivided into 3 subfamilies Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae, and includes herpes simplex virus, varicella-zoster virus, cytomegalovirus, and EB virus (all of which infect humans), pseudorabies virus of swine, equine rhinopneumonitis virus, infectious bovine rhinotracheitis virus, canine herpesvirus, B virus of Old World monkeys, several viruses of New World monkeys, virus III of rabbits, infectious laryngotracheitis virus of fowl, Marek disease virus of chickens, Lucké tumor virus of frogs, and many others.

herpesvirus
herpesvirus (her′pez-vi′rus)

Any virus belonging to the family Herpesviridae.
cercopithecrine h. an h., in the family Herpesviridae, affecting Old World monkeys, that is very similar morphologically to herpes simplex virus; fatal infection may occur in humans following the bite of an infected monkey, although other modes of transmission have also been documented. SYN: B virus.
human h. 1 herpes simplex virus, type 1. See herpes simplex.
human h. 2 herpes simplex virus, type 2. See herpes simplex.
human h. 3 SYN: varicella-zoster virus.
human h. 4 SYN: Epstein-Barr virus.
human h. 5 a highly species-specific h. (Cytomegalovirus) with particular affinity for the salivary gland tissue. SYN: salivary gland virus, salivary virus.
human h. 6 a human h. that was found in certain lymphoproliferative disorders, replicates in a number of different types of leukocytes, and is associated with the childhood disease roseola (exanthema subitum).
human h. 7 virus found in association with human T lymphocytes and is shed in the saliva of most adults; however, a causal relationship to any known disease has not been determined.
human h. 8 a linear double-stranded DNA virus that induces Kaposi sarcoma (KS) in immunodeficient persons. DNA sequences unique to this virus are regularly found in KS specimens from HIV-negative persons as well. The virus is also associated with several uncommon lymphoproliferative syndromes in AIDS patients, including multicentric Castleman disease and primary effusion lymphoma (body cavity–based lymphoma).Among persons with AIDS, Kaposi sarcoma occurs in 15–25% of male homosexuals but only in 1–3% of persons who acquire AIDS by nonsexual routes ( e.g., hemophiliacs and other transfusion recipients). These facts support the hypothesis that the virus is sexually transmitted. KS is characterized histologically by abnormal vascularization and the presence of proliferating endothelial cells, fibroblasts, infiltrating leukocytes, and spindle-shaped tumor cells. Replication of HHV8 occurs only in a small subset of spindle cells, but the majority of such cells are latently infected. Spindle cell proliferation is apparently triggered by growth factors released from HIV-infected cells. Spindle cells, in turn, produce factors that promote angiogenesis. HHV8 DNA can also be found in circulating CD19 B lymphocytes in 40–50% of AIDS patients with KS. Serologic assays are available for anti-HHV8 antibodies, most of them using viral antigen from cell lines derived from body cavity–based lymphomas. Viral replication is insensitive to acyclovir, but is inhibited by ganciclovir, foscarnet, cidofovir, and interferon alpha.
H. saimiri an ubiquitous infection of squirrel monkeys that is highly oncogenic when injected into other monkey species.
suid h. the causative agent of pseudorabies.

herpetic
herpetic (her-pet′ik)

1. Relating to or characterized by herpes. 2. Relating to or caused by a herpesvirus.

herpetiform
herpetiform (her-pet′i-form)

Resembling herpes.

herpetologist
herpetologist (her-pet-ol′o-jist)

One who specializes in herpetology.

herpetology
herpetology (her-pet-ol′o-je)

The branch of zoology concerned with the study of reptiles and amphibians.

Herpetomonas
Herpetomonas (her-pe-tom′o-nas)

A genus of asexual monogenetic flagellates (family Trypanosomatidae) that are strictly insect parasites, with a variety of body forms including promastigote (leptomad), epimastigote (crithidial), amastigote (leishmanial), and trypomastigote (trypanosome-like); infective forms are passed in the host feces. H. muscae domesticae, the type species, is found in the common housefly. [G. herpeton, a reptile (fr. herpo, to creep), + monas, unit (one of the Monadidae)]

Herpetoviridae
Herpetoviridae

Obsolete term for Herpesviridae.

herpetovirus
herpetovirus (her′pe-to-vi′rus)

Obsolete name for a virus belonging to the family Herpesviridae. SEE ALSO: herpesvirus.

Herring
Herring

Percy T., English physiologist, 1872–1967. See H. bodies, under body.

Herrmann
Herrmann

C., Jr., 20th century. See H. syndrome.

Hers
Hers

G., French biochemist. See H. disease.

hersage
hersage (ar-sahzh′)

Separating the individual fibers of a nerve trunk. [Fr. (from L. hirpex, a large rake), a harrowing]

Hertwig
Hertwig

Wilhelm A.O., German embryologist, 1849–1922. See H. sheath.

Hertwig
Hertwig

Richard, German zoologist, 1850–1937. See Magendie-H. sign, Magendie-H. syndrome.

Hertz
Hertz

Heinrich R., German physicist, 1857–1894. See h., hertzian experiments, under experiment.

hertz
hertz (Hz) (herts)

A unit of frequency equivalent to 1 cycle/sec; this term should not be used for radial (circular) frequency or for angular velocity, in which cases the term sec⁻¹ should be used. [H.R. H.]

hertzian hertzian (hert′ze-an)

Attributed to or described by Heinrich R. Hertz.

Herxheimer
Herxheimer

Karl, German dermatologist, 1861–1944. See H. reaction, Jarisch-H. reaction.

herzstoss
herzstoss (harz′stos)

Cardiac systole producing a diffuse precordial heave with or without any definite point of maximal impulse. [Ger. heart thrust]

Heschl
Heschl

Richard L., Austrian pathologist, 1824–1881. See H. gyri, under gyrus.

hesitancy
hesitancy (hez′i-tan-se)

An involuntary delay or inability in starting the urinary stream.

hesitant
hesitant (hez′i-tant)

Term used to descibe the state of RNA polymerase when it is susceptible to pause, arrest or termination signals. SEE ALSO: overdrive, antitermination.

hesperidin
hesperidin (hes-per′i-din)

A flavone diglycoside obtained from unripe citrus fruit, which reputedly possesses vitamin P activity. SYN: cirantin.

Hess
Hess

Carl von, German ophthalmologist, 1860–1923. See H. screen.

Hess
Hess

Walter R., Swiss physiologist and Nobel laureate, 1881–1973. See trophotropic zone of H..

Hesselbach
Hesselbach

Franz K., German anatomist and surgeon, 1759–1816. See H. fascia, H. hernia, H. ligament, H. triangle.

hetastarch
hetastarch (het′a-starch)

A carbohydrate starch derivative used as a cryoprotective agent for erythrocytes. Also used as an extender of blood plasma volume.

heter- heter-

See hetero-.

heteradelphus
heteradelphus (het-er-a-del′fus)

Unequal conjoined twins in which the smaller incomplete parasite is attached to the larger, more nearly normal autosite. See conjoined twins, under twin. [heter- + G. adelphos, brother]

heteralius
heteralius (het-er-a′le-us)

Unequal conjoined twins in which the parasite appears as little more than an excrescence on the autosite. See conjoined twins, under twin. [heter- + G. halios, useless]

heteraxial
heteraxial (het-er-ak′se-al)

Having mutually perpendicular axes of unequal length.

heterecious
heterecious (het-er-e′shus)

Having more than one host; said of a parasite passing different stages of its life cycle in different animals. SYN: metoxenous. [heter- + G. oikion, home]

heterecism
heterecism (het′er-e-sizm)

The occurrence, in a parasite, of two cycles of development passed in two different hosts. SYN: metoxeny (1) . [heter- + G. oikion, home]

heteresthesia
heteresthesia (het-er-es-the′ze-a)

A change occurring in the degree (either plus or minus) of the sensory response to a cutaneous stimulus as the latter crosses a certain line on the surface. [heter- + G. aisthesis, sensation]

hetero- hetero-, heter-

The other, different; opposite of homo- [G. heteros, other]

heteroagglutinin
heteroagglutinin (het′er-o-a-gloo′ti-nin)

A form of hemagglutinin, one that agglutinates the red blood cells of species other than that in which the h. occurs. SEE ALSO: hemagglutinin.

heteroalleles
heteroalleles (het′er-o-a-lelz′)

Genes that have undergone mutation at different nucleotide positions and therefore result from different mutational events. Cf.:eualleles.

heteroantibody
heteroantibody (het′er-o-an′ti-bod-e)

Antibody that is heterologous with respect to antigen, in contradistinction to isoantibody.

heteroantiserum
heteroantiserum (het′er-o-an′ti-se-rum)

Antiserum developed in one animal species against antigens or cells of another species.

heteroatom
heteroatom (het′er-o-at′om)

An atom, other than carbon, located in the ring structure of an organic compound, as the N in pyridines or pyrimidines (heterocyclic compounds).

heteroblastic
heteroblastic (het-er-o-blas′tik)

Developing from more than a single type of tissue. [hetero- + G. blastos, germ]

heterocellular
heterocellular (het′er-o-sel′u-lar)

Formed of cells of different kinds.

heterocentric
heterocentric (het′er-o-sen′trik)

1. Having different centers; said of rays that do not meet at a common focus. Cf.:homocentric. 2. SYN: allocentric. [hetero- + G. kentron, center]

heterocephalus
heterocephalus (het-er-o-sef′a-lus)

Conjoined twins with heads of unequal size. See conjoined twins, under twin. [hetero- + G. kephale, head]

heterocheiral
heterocheiral, heterochiral (het-er-o-ki′ral)

Relating to or referred to the other hand. [hetero- + G. cheir, hand]

heterochromatic
heterochromatic (het′er-o-kro-mat′ik)

Characteristic of heterochromatin.

heterochromatin
heterochromatin (het′er-o-kro′ma-tin)

The part of the chromonema that remains tightly coiled and condensed during interphase and thus stains readily. SYN: heteropyknotic chromatin.
constitutive h. repetitive h. that lies in secondary constrictions in the nucleolar organizers.
facultative h. nonrepetitive h. that comprises translatable sequences of DNA.
satellite-rich h. h. that codes for 18 S and 28 S components of ribosomal RNA and is located close to the centromeres of certain chromosomes.

heterochromia
heterochromia (het′er-o-kro′me-a)

A difference in coloration in two structures which are normally alike in color. [hetero- + G. chroma, color]
atrophic h. h. iridis after trauma or inflammation, or in old age.
binocular h. an increase or decrease in pigmentation of one eye, with or without extraocular pigmentary defects.
h. iridis, h. of iris a difference in coloration of the irides. See binocular h..
monocular h. SYN: iris bicolor.
simple h. h. iridis appearing as a developmental defect, without any innervation defect.
sympathetic h. h. iridis occurring after lesions of the cervical sympathetic nerves.

heterochromous
heterochromous (het′er-o-kro′mus)

Having an abnormal difference in coloration.

heterochron
heterochron (het′er-o-kron)

Having varying chronaxies. [hetero- + G. chronos, time]

heterochronia
heterochronia (het-er-o-kro′ne-a)

Origin or development of tissues or organs at an unusual time or out of the regular sequence. Cf.:synchronia. [hetero- + G. chronos, time]

heterochronic
heterochronic (het-er-o-kron′ik)

SYN: heterochronous.

heterochronous
heterochronous (het-er-ok′ro-nus)

Relating to heterochronia. SYN: heterochronic.

heterocladic
heterocladic (het′er-o-klad′ik)

Denoting an anastomosis between branches of different arterial trunks, as distinguished from homocladic. [hetero- + G. klados, a twig]

heterocrine
heterocrine (het′er-o-krin)

Denoting the secretion of two or more kinds of material. [hetero- + G. krino, to separate]

heterocrisis
heterocrisis (het′er-o-kri′sis)

Rarely used term for an irregular crisis, one occurring at an abnormal time or with unusual symptoms.

heterocytotropic
heterocytotropic (het′er-o-si′to-trop′ik)

Having an affinity for cells of a different species. [hetero- + G. kytos, cell, + trope, a turning toward]

heterodisperse
heterodisperse (het′er-o-dis-pers′)

Of varying size; describing aerosols whose particles are not uniform in size.

heterodont
heterodont (het′er-o-dont)

Having teeth of varying shapes, such as those of humans and the majority of mammals, in contrast to homodont. [hetero- + G. odous, tooth]

Heterodoxus spiniger
Heterodoxus spiniger (het-er-o-dok′sus spi′ni-ger)

A biting louse of the dog, sometimes called the kangaroo louse.

heterodromous
heterodromous (het-er-od′ro-mus)

Moving in the opposite direction. [hetero- + G. dromos, running]

heteroduplex
heteroduplex (het′er-o-doo′pleks)

1. A DNA molecule, the two constitutive strands of which derive from distinct sources and hence are likely to be somewhat mismatched. 2. A DNA-RNA hybrid. [hetero- + L. duplex, two-fold]

heterodymus
heterodymus (het-er-od′i-mus)

Unequal conjoined twins in which the incomplete parasite, consisting of head and neck and, to some extent, thorax, is attached to the anterior surface of the autosite. See conjoined twins, under twin. [hetero- + G. didymos, twin]

heteroeroticism
heteroeroticism (het′er-o-e-rot′i-sism)

A condition of sexual excitement brought about by congress with a person of the opposite sex.

heterogametic
heterogametic (het′er-o-ga-met′ik)

Having sex gametes of contrasting types; human males are h.. SYN: digametic. [hetero- + G. gametikos, connubial]

heterogamous
heterogamous (het-er-og′a-mus)

Relating to heterogamy.

heterogamy
heterogamy (het-er-og′a-me)

1. Conjugation of unlike gametes. 2. Bearing different types of flowers. 3. Reproduction by indirect methods of pollination. [hetero- + G. gamos, marriage]

heterogeneity
heterogeneity (het′er-o-je-ne′i-te)

Heterogeneous state or quality.
genetic h. the character of a phenotype produced by mutation at more than one gene or by more than one genetic mechanism. See genocopy.

heterogeneous
heterogeneous (het′er-o-je′ne-us)

Comprising elements with various and dissimilar properties.

heterogenesis
heterogenesis (het′er-o-jen′e-sis)

1. Alternation of generations. 2. SYN: asexual generation. 3. SYN: spontaneous generation. [hetero- + G. genesis, production]

heterogenetic
heterogenetic (het′er-o-je-net′ik)

Relating to heterogenesis.

heterogenic
heterogenic, heterogeneic (het′er-o-jen′ik, -je-ne′ik)

Having different gene constitutions, especially in diverse species.

heterogenote
heterogenote (het′er-o-je′not)

In microbial genetics, an organism that contains exogenous genetic material that differs somewhat from the corresponding region of its own original genome, but in a very limited way resembles a heterozygote.

heterogenous
heterogenous (het-er-oj′e-nus)

Of foreign origin. Commonly confused with heterogeneous.

heteroglycan
heteroglycan (het′er-o-gli′kan)

SYN: heteropolysaccharide.

heterograft
heterograft (het′er-o-graft)

SYN: xenograft.

heterokaryon
heterokaryon (het′er-o-kar′e-on)

A cell containing diverse nuclei inside a common cytoplasm, usually resulting from the artificial fusion of two cells from different species. [hetero- + G. karyon, kernel, nut]

heterokaryotic
heterokaryotic (het′er-o-kar-e-ot′ik)

Exhibiting the properties of a heterokaryon.

heterokeratoplasty
heterokeratoplasty (het′er-o-ker′a-to-plas-te)

Keratoplasty in which the cornea from one species of animal is grafted to the eye of another species.

heterokinesia
heterokinesia (het′er-o-ki-ne′ze-a)

Executing movements the reverse of those one is told to make. SYN: heterokinesis (2) . [hetero- + G. kinesis, movement]

heterokinesis
heterokinesis (het′er-o-ki-ne′sis)

1. Differential distribution of X and Y chromosomes during meiotic cell division. 2. SYN: heterokinesia. [hetero- + G. kinesis, movement hetero- + G. kinesis, movement]

heterolateral
heterolateral (het′er-o-lat′er-al)

SYN: contralateral. [hetero- + L. latus, side]

heterolipids
heterolipids (het′er-o-lip′idz)

1. Lipids containing N and P atoms in addition to the usual C, H, and O. 2. Any complex lipids. Cf.:homolipids.

heteroliteral
heteroliteral (het′er-o-lit′er-al)

Substitution of one letter for another in the pronunciation of certain words. [hetero- + L. littera, letter]

heterologous
heterologous (het-er-ol′o-gus)

1. Pertaining to cytologic or histologic elements occurring where they are not normally found. SEE ALSO: xenogeneic. 2. Derived from an animal of a different species, as the serum of a horse is h. for a rabbit. [hetero- + G. logos, ratio, relation]

heterology
heterology (het-er-ol′o-je)

A departure from the normal in structure, arrangement, or mode or time of development.

heterolysin
heterolysin (het-er-ol′i-sin)

A lysin that is formed in one species of animal and manifests lytic activity on the cells of a different species.

heterolysis
heterolysis (het-er-ol′i-sis)

Dissolution or digestion of cells or protein components from one species by a lytic agent from a different species. [hetero- + G. lysis, a loosening]

heterolytic
heterolytic (het′er-o-lit′ik)

Pertaining to heterolysis or to the effect of a heterolysin.

heteromastigote
heteromastigote (het-er-o-mas′ti-got)

A flagellate having two flagella, one anterior and one posterior. [hetero- + G. mastix, a whip]

heteromeral
heteromeral (het′er-om′er-al)

SYN: heteromeric (2) .

heteromeric
heteromeric (het′er-o-mar′ik)

1. Having a different chemical composition. 2. Denoting spinal neurons that have processes passing over to the opposite side of the cord. SYN: heteromeral, heteromerous. [hetero- + G. meros, part]

heteromerous
heteromerous (het′er-om′er-us)

SYN: heteromeric (2) .

heterometabolous
heterometabolous (het′er-o-me-tab′o-lus)

Pertaining to a member of the Heterometabola, a superorder sometimes used for a series of insect orders in which incomplete metamorphosis is found. [hetero- + G. metabole, change]

heterometaplasia
heterometaplasia (het′er-o-met-a-pla′ze-a)

Tissue transformation resulting in production of a tissue foreign to the part where produced.

heterometric
heterometric (het′er-o-met′rik)

Involving or depending upon a change in size. [hetero- + G. metron, measure]

heterometropia
heterometropia (het′er-o-me-tro′pe-a)

A condition in which the refraction is different in the two eyes. [hetero- + G. metron, measure, + ops, eye]

heteromorphism
heteromorphism (het′er-o-morf′izm)

In cytogenetics, a difference of shape or size in metaphase between the two homologous chromosomes. [hetero- + G. morphe, shape]

heteromorphosis
heteromorphosis (het′er-o-mor-fo′sis)

1. Development of one tissue from a tissue of another kind or type. 2. Embryonic development of tissue or an organ inappropriate to its site. [hetero- + G. morphosis, a molding]

heteromorphous
heteromorphous (het′er-o-mor′fus)

Differing from the normal form.

heteronomous
heteronomous (het-er-on′o-mus)

1. Different from the type; abnormal. 2. Subject to the direction or control of another; not self-governing. Cf.:autonomous. [hetero- + G. nomos, law]

heteronomy
heteronomy (het-er-on′o-me)

The condition or state of being heteronomous. [hetero- + G. nomos, law]

heteronuclear
heteronuclear (het′er-o-noo′kle-er)

Denoting a heterokaryon that has lost some of the nuclear material of which the cell line was originally constituted.

heteronymous
heteronymous (het-er-on′i-mus)

Having different names or expressed in different terms. [G. heteronymos, having a different name, fr. onyma, or onoma, name]

heteropagus
heteropagus (het-er-op′a-gus)

Unequal conjoined twins in which the imperfectly developed parasite is attached to the ventral portion of the autosite. See conjoined twins, under twin. SEE ALSO: epigastrius. [hetero- + G. pagos, fixed]

heteropathy
heteropathy (het′er-op′a-the)

1. Abnormal sensitivity to stimuli. 2. SYN: allopathy. [hetero- + G. pathos, suffering]

heterophagy
heterophagy (het-er-of′a-je)

Digestion within a cell of an exogenous substance phagocytosed from the cell's environment. [hetero- + G. phago, to eat]

heterophil
heterophil, heterophile (het′er-o-fil, -fil)

1. Pertaining to heterogenetic or cross-reacting antigens occurring in different species or to antibodies directed against such antigens. 2. The neutrophilic leukocyte in man; in some animals the granules vary in size and staining reaction. [hetero- + G. philos, fond]

heterophonia
heterophonia (het′er-o-fo′ne-a)

1. The change of voice at puberty. 2. Any abnormality in the voice sounds. SYN: heterophthongia. [hetero- + G. phone, voice]

heterophoria
heterophoria (het′er-o-fo′re-a)

A tendency for deviation of the eyes from parallelism, prevented by binocular vision. [hetero- + G. phora, movement]

heterophthalmus
heterophthalmus (het′er-of-thal′mus)

A seldom-used term for a difference in the appearance of the two eyes, usually due to heterochromia iridis. SYN: allophthalmia. [hetero- + G. ophthalmos, eye]

heterophthongia
heterophthongia (het-er-of-thon′je-a)

SYN: heterophonia. [G. heterophthongos, fr. heteros, different, + phthongos, sound, voice]

Heterophyes
Heterophyes (het-er-of′i-ez)

A genus of digenetic flukes (family Heterophyidae) parasitic in fish-eating birds and mammals, including man; cercariae from infected snails penetrate and encyst in fish, which are eaten by the final hosts. [hetero- + G. phye, stature, form]
H. brevicaeca a species reported in humans in the Philippines and implicated in heart lesions caused by the eggs of this minute fluke, carried from the intestinal mucosa to obstruct coronary capillaries.
H. h. the Egyptian intestinal or small intestinal fluke, a species infecting the small intestine and cecum in humans and other fish-eating mammals in Egypt and the Far East.
H. katsuradai a species, somewhat smaller than H. h., found in Japan.

heterophyiasis
heterophyiasis (het′er-o-fi-i′a-sis)

Infection with a heterophyid trematode, particularly Heterophyes heterophyes. SYN: heterophyidiasis.

heterophyid
heterophyid (het′er-o-fi′id)

Common name for a member of the family Heterophyidae.

Heterophyidae
Heterophyidae (het′er-o-fi′i-de)

A family of tiny fish-borne trematodes, including the genus Heterophyes and its common human parasite, H. heterophyes.

heterophyidiasis
heterophyidiasis (het′er-o-fi-id-i′a-sis)

SYN: heterophyiasis.

heteroplasia
heteroplasia (het′er-o-pla′ze-a)

1. Development of cytologic and histologic elements that are not normal for the organ or part in question, as the growth of bone in a site where there is normally fibrous connective tissue. 2. Malposition of tissue or a part that is otherwise normal, as a ureter that develops at the lower pole of a kidney. SYN: alloplasia. [hetero- + G. plasis, a forming]

heteroplastic
heteroplastic (het′er-o-plas′tik)

1. Pertaining to or manifesting heteroplasia. 2. Relating to heteroplasty.

heteroplastid
heteroplastid (het′er-o-plas′tid)

The graft in heteroplasty.

heteroploid
heteroploid (het′er-o-ployd)

Relating to heteroploidy.

heteroploidy
heteroploidy (het′er-o-ploy′de)

The state of a cell possessing some number of complete haploid sets other than the normal. [hetero- + G. ploides, in form]

heteropolysaccharide
heteropolysaccharide (het′er-o-pol-e-sak′a-rid)

A polysaccharide composed of two or more different types of monosaccharides. Cf.:glycan, homoglycan. SYN: heteroglycan.

heteroproteose
heteroproteose (het′er-o-pro′te-os)

See primary proteose.

heteropyknosis
heteropyknosis (het′er-o-pik-no′sis)

Any state of variable density or condensation, usually in different chromosomes or between different regions of the same chromosome; a region may be attentuated (negative h) or accentuated (positive h). [hetero- + G. pyknos, dense]

heteropyknotic
heteropyknotic (het′er-o-pik-not′ik)

Relating to or characterized by heteropyknosis.

heteroreceptor
heteroreceptor (het′er-o-re-sep′ter)

A site on a neuron that binds a modulatory neuroregulator other than that released by the neuron. [hetero- + receptor]

heterosaccharide
heterosaccharide (het′er-o-sak′a-rid)

A glycoside in which a sugar group is attached to a nonsugar group; e.g., amygdalin.

heteroscedasticity
heteroscedasticity (het′er-o-sked-as-tis′i-te)

Non-constancy of the variance of a measure over the levels of the factor under study. [hetero + G. skedastikos, pertaining to scattering, fr. skedannumi, to scatter]

heterosexual
heterosexual (het′er-o-sek′shoo-al)

1. A person whose sexual orientation is toward persons of the opposite sex. 2. Relating to or characteristic of heterosexuality. 3. One whose interests and behavior are characteristic of heterosexuality.

heterosexuality
heterosexuality (het′er-o-sek-shoo-al′i-te)

Erotic attraction, predisposition, or activity, including sexual congress between persons of the opposite sex.

heteroside
heteroside (het′er-o-sid)

A compound containing two or more different carbohydrate residues that are covalently linked to a noncarbohydrate moiety.

heterosis
heterosis (het-er-o′sis)

The beneficial effect on the phenotype of crossing (hybridization) upon growth, vigor, and physical or mental qualities in a strain of plants or in animal stock, as measured by the difference between the midparent mean phenotype and that of F₁; also referred to as hybrid vigor. [hetero- + -osis, condition]

heterosmia
heterosmia (het′er-os′me-a)

SYN: allotriosmia.

heterosome
heterosome (het′er-o-som)

In genetics, the chromosome pair that is different in the two sexes. See sex chromosomes, under chromosome. [hetero- + G. soma, body]

heterospecific
heterospecific (het′er-o-spe-sif′ik)

Heterologous, as pertains to grafts.

heterosuggestion
heterosuggestion (het′er-o-sug-jes′chun)

A rarely used term for hypnotic suggestion received from another person; opposed to autosuggestion.

heterotaxia
heterotaxia (het′er-o-taks′e-a)

Abnormal arrangement of organs or parts of the body in relation to each other. SYN: heterotaxis, heterotaxy. [hetero- + G. taxis, arrangement]
cardiac h. dextrocardia.

heterotaxic
heterotaxic (het-er-o-taks′ik)

Abnormally placed or arranged.

heterotaxis
heterotaxis, heterotaxy (het-er-o-taks′is, het′er-o-taks-e)

SYN: heterotaxia.

heterothallic
heterothallic (het′er-o-thal′ik)

In fungi, denoting a kind of sexual reproduction in which a sexual spore is produced only by fusion with a nucleus of another mating type. Cf.:homothallic. [hetero- + G. thallos, a young shoot]

heterotherm
heterotherm (het′er-o-therm)

A heterothermic animal.

heterothermic
heterothermic (het′er-o-ther′mik)

Having partial regulation of body temperature; between poikilothermic and homeothermic.

heterotic
heterotic (het-er-ot′ik)

Relating to heterosis.

heterotonia
heterotonia (het′er-o-to′ne-a)

Abnormality or variation in tension or tonus. [hetero- + G. tonos, tension]

heterotopia
heterotopia (het-er-o-to′pe-a)

1. SYN: ectopia. 2. In neuropathology, displacement of gray matter, typically into the deep cerebral white matter. [hetero- + G. topos, place]
h. maculae SYN: ectopia maculae.

heterotopic
heterotopic (het-er-o-top′ik)

1. SYN: ectopic (1) . 2. Relating to heterotopia (2). [hetero- + topos, place, + suffix -ic, pertaining to]

heterotopous
heterotopous (het-er-ot′o-pus)

Heterotopic, especially in reference to teratomas composed of tissues that are out of place in the region where found.

heterotransplantation
heterotransplantation (het′er-o-tranz-plan-ta′shun)

Transfer of a heterograft (xenograft).

heterotrichosis
heterotrichosis (het′er-o-tri-ko′sis)

A condition characterized by hair growth of variegated color. [hetero- + G. trichosis, growth of hair]

heterotroph
heterotroph (het′er-o-trof, -trof)

A microorganism that obtains its carbon, as well as its energy, from organic compounds. SEE ALSO: autotroph. [hetero- + G. trophe, nourishment]

heterotrophic
heterotrophic (het′er-o-tro-fik)

1. Relating to or exhibiting the properties of heterotrophy. 2. Relating to a heterotroph.

heterotrophy
heterotrophy (het′er-o-tro-fe)

The ability or requirement to synthesize all metabolites from organic compounds.

heterotropia
heterotropia, heterotropy (het′er-o-tro′pe-a, het-er-ot′ro-pe)

SYN: strabismus. [hetero- + G. trope, a turning]

heterotypic
heterotypic (het′er-o-tip′ik)

Of a different or unusual type or form.

heteroxanthine
heteroxanthine (het′er-o-zan′thin)

7-Methylxanthine;one of the alloxuric bases in urine, representing end products of purine metabolism.

heteroxenous
heteroxenous (het-er-oks′e-nus)

SYN: digenetic (1) . [hetero- + G. xenos, stranger]

heterozoic
heterozoic (het-er-o-zo′ik)

Relating to another animal or another species of animal. [hetero- + G. zoikos, relating to an animal]

heterozygosity
heterozygosity, heterozygosis (het′er-o-zi-gos′i-te, -zi-go′sis)

The state of being heterozygous. [hetero- + G. zygon, a yoke]

heterozygote
heterozygote (het′er-o-zi′got)

A heterozygous individual. [hetero- + G. zygotos, yoked]
compound h. in medical genetics, the presence of two different mutant alleles at the same loci. SYN: genetic compound.
manifesting h. an organism heterozygous for what is ordinarily a recessive condition which, as a result of special mechanisms (such as lyonization, allelic exclusion, or a deletion in the homologous chromosome), has phenotypic manifestations. SYN: manifesting carrier.

heterozygous
heterozygous (het′er-o-zi′gus)

Having different alleles at one locus regarding a specific character; heterotic.
doubly h. in the analysis of linkage between two loci, denoting that genotype in which a parent is h. at both loci, the state that on average contains the maximum information about the linkage.

Heubner
Heubner

Johann O.L., German pediatrician, 1843–1926. See artery of H., H. arteritis.

Heurenius
Heurenius

Johannes. See van Horne.

Heuser
Heuser

Chester H., U.S. embryologist, 1885–1965. See H. membrane.

HEV
HEV

Abbreviation for hepatitis E virus.

hexa- hexa-, hex-

Prefix denoting six. [G. hex]

hexacanth
hexacanth (hek′sa-kanth)

The motile six-hooked first-stage larva of cyclophyllidean cestodes; it emerges from the egg and actively claws its way through the intermediate host's intestine prior to development into the next larval stage; e.g., the h. of Taenia saginata, which penetrates the intestine of a cow that ingested the egg, then forms a cysticercus in the muscles of the intermediate host. SYN: oncosphere. [hexa- + G. akantha, hook or thorn]

hexachlorocyclohexane
hexachlorocyclohexane (hek-sa-klo′ro-si-klo-hek′san)

SYN: gamma benzene hexachloride.

hexachlorophane
hexachlorophane (hek-sa-klo′ro-fan)

SYN: hexachlorophene.

hexachlorophene
hexachlorophene (hek-sa-klo′ro-fen)

An antibacterial; formerly widely used in soaps and detergents to inhibit bacterial growth; excessive use causes neurologic lesions; currently limited use. SYN: hexachlorophane.

hexacosanoic acid
hexacosanoic acid (heks′a-ko′san-o-ik)

Systemic name for cerotinic acid.

hexacosanol
hexacosanol (heks-a-ko′sa-nol)

See ceryl.

hexacosyl
hexacosyl (heks-a-ko′sil)

SYN: ceryl.

hexad
hexad (heks′ad)

A sexivalent element or radical.

hexadactyly
hexadactyly, hexadactylism (hek′sa-dak′ti-le, -lizm)

The presence of six fingers or six toes on one or both hands or feet. [hexa- + G. daktylos, finger]

hexadecanoic acid
hexadecanoic acid (hek′sa-dek-a-no′ik)

SYN: palmitic acid.

1-hexadecanol
1-hexadecanol (hek-sa-dek′a-nol)

SYN: cetyl alcohol.

hexafluorenium bromide
hexafluorenium bromide (hek′sa-floo-ren′e-um)

A potentiator for succinylcholine in anesthesiology by producing a mild nondepolarizing neuromuscular blockade; also inhibits plasma cholinesterase.

hexamer
hexamer (hek′sa-mer)

1. A group of six protein subunits that form a capsomere on the surface of an icosohedral virus. 2. A complex or compound containing six subunits or moieties ( e.g., a protein complex with six polypeptide chains or an oligopeptide with six amino acid residues). [hexa- + G. meros, part]

hexameric
hexameric (heks′a-mer-ik)

Containing six subunits or moieties.

hexametazime
hexametazime (HMPAO)

A lipophilic substance that readily crosses the blood-brain barrier; combined with ^99mTc to produce a radiopharmaceutical for SPECT imaging or cerebral blood flow estimates. SYN: hexamethylpropyleneamine oxime.

hexamethylpropyleneamine oxime
hexamethylpropyleneamine oxime (heks-a-meth′il-pro′pi-len- a-men oks′em)

SYN: hexametazime.

hexamidine isethionate
hexamidine isethionate (hek-sam′i-den)

A topical antiseptic.

hexamine
hexamine (hek′sa-men)

SYN: methenamine.

hexane
hexane (hek′san)

A saturated hydrocarbon, C₆H₁₄, of the paraffin series (typically n-h., CH₃&cbond;(CH₂)₄&cbond;CH₃).

hexanoate
hexanoate (hek′sa-no-at)

SYN: caproylate.

hexanoyl
hexanoyl (hek′sa-no-il)

SYN: caproyl.

hexapeptide
hexapeptide (heks′a-pep′tid)

A peptide containing six amino acid residues.

hexaploidy
hexaploidy (heks′a-ploy-de)

See polyploidy.

Hexapoda
Hexapoda (hek-sap′o-da)

SYN: Insecta. [hexa- + G. pous, foot]

hexestrol
hexestrol (hek-ses′trol)

A synthetic meso-compound with estrogenic activity.

hexitol
hexitol (heks′i-tol)

The polyol (sugar alcohol) obtained on the reduction of a hexose ( e.g., d-sorbitol).

hexokinase
hexokinase (heks-o-ki′nas)

A phosphotransferase present in yeast, muscle, brain, and other tissues that catalyzes the ATP-dependent phosphorylation of d-glucose and other hexoses to form d-glucose 6-phosphate (or other hexose 6-phosphates); the first step in glycolysis; a deficiency of h. can result in hemolytic anemia and impaired glycolysis.

hexon
hexon (heks′on)

One of a group of six protein units (hexamer unit) on the triangular face of an icosohedral capsomere on certain viruses. [hex- + -on]

hexonic acid
hexonic acid (heks-on′ik)

The aldonic acid obtained on the oxidation of the aldehyde group of an aldohexose to a carboxylic acid ( e.g., gluconic acid from glucose).

hexosamine
hexosamine (hek′so-sam′en)

The amine derivative (NH₂ replacing OH) of a hexose; e.g., glucosamine.

hexosaminidase
hexosaminidase (hek′so-sa-min′i-das)

General term for enzymes cleaving N-acetylhexose ( e.g., N-acetylglucosamine) residues from gangliosidelike oligosaccharides. At least four specific enzymes carrying out this type of reaction are known: α-N-acetyl-d-galactosaminidase, α-N-acetyl-d-glucosaminidase, β-N-acetyl-d-h., and β-N-acetyl-d-galactosaminidase, each being specific for the configuration and type of sugar included in the name.
h. A a hydrolytic enzyme that acts on ganglioside G_M2, producing N-acetyl-d-galactosamine and ganglioside G_M3; a deficiency of this enzyme is associated with Tay-Sachs disease.
h. B a hydrolytic enzyme that acts on ganglioside G_M1, producing ganglioside G_M1 and galactose, as well as on globoside, producing N-acetylgalactosamine and trihexosylceramide; a deficiency of this enzyme is associated with Sandhoff disease.

hexosans
hexosans (hek′so-sanz)

Polysaccharides with the general formula (C₆H₁₀O₅)_x that, on hydrolysis, yield hexoses; included are glucosans (glucans), mannans, galactans, and fructosans (fructans). SYN: polyhexoses.

hexose
hexose (hek′sos)

A monosaccharide containing six carbon atoms in the molecule (C₆H₁₂O₆); d-glucose is the principal h. in nature.

hexosebisphosphatase
hexosebisphosphatase, hexosediphosphatase (hek′sos-bis-fos′fa-tas, -di-)

SYN: fructose 1,6-bisphosphate.

hexose phosphatase
hexose phosphatase (hek′sos fos′fa-taz)

An enzyme catalyzing the hydrolysis of a hexose phosphate to a hexose ( e.g., glucose-6-phosphatase).

hexosephosphate isomerase
hexosephosphate isomerase (hek-sos-fos′fat)

SYN: glucose-phosphate isomerase.

hexose-1-phosphate uridylyltransferase
hexose-1-phosphate uridylyltransferase

SYN: UDPglucose-hexose-1-phosphate uridylyltransferase.

hexulose
hexulose (hek′su-los)

SYN: ketohexose.

hexuronic acid
hexuronic acid (hek-sur-on′ik)

The uronic acid of a hexose.

hexyl
hexyl (hek′sil)

The radical of hexane, CH₃(CH₂)₄CH₂&cbond;.

hexylresorcinol
hexylresorcinol (hek′sil-re-sor′si-nol)

A broad spectrum anthelmintic and antiseptic.

Hey
Hey

William, English surgeon, 1736–1819. See H. amputation, H. hernia, H. ligament.

Heyer
Heyer

W.T., U.S. scientist, *1902. See H.-Pudenz valve.

Hf
Hf

Symbol for hafnium.

Hg
Hg

Symbol for mercury (hydrargyrum).

HGE
HGE

Abbreviation for human granulocytic ehrlichiosis.

HGF
HGF

Abbreviation for hyperglycemic-glycogenolytic factor.

HGH
HGH

Abbreviation for human growth hormone. See somatotropin.

HGPRT
HGPRT

Abbreviation for hypoxanthine guanine phosphoribosyltransferase.

HGSIL
HGSIL

Abbreviation for high-grade squamous intraepithelial lesion.

HGV
HGV

Abbreviation for hepatitis G virus.

HHV
HHV

Abbreviation for human herpesvirus.

hiatal
hiatal (hi-a′tal)

Relating to a hiatus.

hiatus
hiatus (hi-a′tus) [TA]

An aperture, opening, or foramen. [L. an aperture, fr. hio, pp. h., to yawn]
adductor h. [TA] the aperture in the aponeurotic insertion of the adductor magnus that transmits the femoral artery and vein from the adductor canal to the popliteal space. SYN: h. adductorius [TA] , femoral opening, h. tendineus, tendinous opening.
h. adductorius [TA] SYN: adductor h..
aortic h. [TA] the opening in the diaphragm bounded by the two crura, the vertebral column, and the median arcuate ligament, through which pass the aorta and thoracic duct. SYN: h. aorticus [TA] , aortic foramen, aortic opening.
h. aorticus [TA] SYN: aortic h..
Breschet h. SYN: helicotrema.
h. canalis facialis SYN: h. for greater petrosal nerve.
h. canalis nervi petrosi majoris [TA] SYN: h. for greater petrosal nerve.
h. canalis nervi petrosi minoris [TA] SYN: h. for lesser petrosal nerve.
esophageal h. [TA] the opening in the right crus of the diaphragm, between the central tendon and the h. aorticus, through which pass the esophagus and the two vagus nerves. SYN: h. esophageus [TA] , esophageal opening.
h. esophageus [TA] SYN: esophageal h..
h. ethmoidalis SYN: semilunar h..
h. of facial canal SYN: h. for greater petrosal nerve.
fallopian h. SYN: h. for greater petrosal nerve.
h. for greater petrosal nerve [TA] the opening on the anterior aspect of the petrous part of the temporal bone that leads to the facial canal and gives passage to the greater petrosal nerve. SYN: h. canalis nervi petrosi majoris [TA] , fallopian h., Ferrein foramen, h. canalis facialis, h. of facial canal.
h. for lesser petrosal nerve [TA] the small opening in the petrous bone lateral to the h. for greater petrosal nerve that gives passage to the lesser petrosal nerve. SYN: h. canalis nervi petrosi minoris [TA] , Arnold canal, canalis nervi petrosi superficialis minoris.
h. maxillaris [TA] SYN: maxillary h..
maxillary h. [TA] the large opening into the maxillary sinus on the nasal surface of the maxilla. SYN: h. maxillaris [TA] .
pleuropericardial h. an opening connecting the pleural and pericardial cavities; usually the result of incomplete development of the pleuropericardial fold of the embryo.
pleuroperitoneal h. an opening through the diaphragm, connecting pleural and peritoneal cavities, usually the result of defective development of the pleuroperitoneal membrane in the embryo; if the defect is extensive there may be herniation of digestive organs into the pleural cavity. SEE ALSO: diaphragmatic hernia. SYN: Bochdalek foramen.
sacral h. [TA] a normally occurring gap at the lower end of the sacrum, exposing the vertebral canal, due to failure of the laminae of the last sacral segment to coalesce. It is closed by the sacrococcygeal ligament, and provides cannular access to the sacral epidural space for administration of anesthetics (caudal nerve blocks). SYN: h. sacralis [TA] .
h. sacralis [TA] SYN: sacral h..
saphenous h. SYN: saphenous opening.
h. saphenus [TA] SYN: saphenous opening.
scalene h. triangular gap bounded by the scalenus anterior and scalenus medius muscles and the first rib to which the muscles attach; the h. provides passage for the subclavian artery and the roots of the brachial plexus. Compression of the structures passing through the h. by any means is manifest as “thoracic outlet syndrome.” SYN: interscalene triangle.
Scarpa h. SYN: helicotrema.
semilunar h. [TA] a deep, narrow groove in the lateral wall of the middle meatus of the nasal cavity, into which the maxillary sinus, the frontonasal duct, and the middle ethmoid cells open. SYN: h. semilunaris [TA] , h. ethmoidalis.
h. semilunaris [TA] SYN: semilunar h..
h. subarcuatus SYN: subarcuate fossa.
h. tendineus SYN: adductor h..
h. totalis sacralis developmental clefting in all sacral vertebrae; may also involve adjacent lumbar vertebrae.

hibernation
hibernation (hi-ber-na′shun)

A torpid condition in which certain animals pass the cold months. True hibernators, such as woodchucks, ground squirrels, dormice, and some others, have body temperatures reduced to near the freezing point, with a very slow heartbeat, low metabolism, and infrequent respirations. Partial hibernators, such as bears, skunks, and raccoons, have reduced physiologic activity during the cold months, but they are not comatose. Cf.:estivation. SYN: winter sleep. [L. hibernus, relating to winter]

hibernoma
hibernoma (hi′ber-no′ma)

A rare type of benign neoplasm in humans, consisting of brown fat that resembles the fat in certain hibernating animals; individual tumor cells contain multiple lipid droplets. SEE ALSO: brown fat. [L. hibernus, pertaining to winter, + G. -oma, tumor]
interscapular h. SYN: brown fat.

hiccup
hiccup, hiccough (hik′up)

A diaphragmatic spasm causing a sudden inhalation that is interrupted by a spasmodic closure of the glottis, producing a noise. SYN: singultus.
epidemic h. a persistent h. occurring as a complication of influenza.

Hickman
Hickman

Robert o., 20th century U.S. pediatric surgeon. See H. catheter.

Hicks
Hicks

See Braxton H..

HIDA
HIDA

Abbreviation for dimethyl iminodiacetic acid.

hidr- hidr-

See hidro-.

hidradenitis
hidradenitis (hi-drad′e-ni′tis)

Inflammation of the sweat glands. SYN: hydradenitis. [G. hidros, sweat, + aden, gland, + -itis, inflammation]
h. suppurativa chronic suppurative folliculitis of apocrine sweat-gland–bearing skin of the perianal, axillary, and genital areas or under the breasts, developing after puberty and producing abscesses or sinuses with scarring.
neutrophilic eccrine h. an inflammatory condition occuring in patients receiving chemotherapy, with deep eccrine gland neutrophil infiltration.

hidradenoma
hidradenoma (hi-drad-e-no′ma)

A benign neoplasm derived from epithelial cells of sweat glands. SYN: hydradenoma. [G. hidros, sweat, + aden, gland, + -oma, tumor]
clear cell h. a tumor derived from eccrine sweat glands, composed of glycogen-rich clear cells. SYN: eccrine acrospiroma, nodular h..
nodular h. SYN: clear cell h..
papillary h. a solitary benign tumor occurring in women usually in the labia majora, cystic and papillary, and composed of epithelium resembling that of apocrine glands. SYN: apocrine adenoma, h. papilliferum.
h. papilliferum SYN: papillary h..

hidro- hidro-, hidr-

Sweat, sweat glands. Cf.:sudor-. [G. hidros]

hidroa
hidroa (hi-dro′a)

SYN: hydroa.

hidrocystoma
hidrocystoma (hi′dro-sis-to′ma)

A cystic form of hidradenoma, usually apocrine. SYN: hydrocystoma (2) , syringocystoma. [hidro- + G. kystis, bladder, + -oma, tumor]
apocrine h. SYN: sudoriferous cyst.

hidromeiosis
hidromeiosis (hi′dro-mi-o′sis)

A decline in the rate of sweating during exposure to heat, especially that from warm baths. [hidro- + G. meiosis, a lessening]

hidropoiesis
hidropoiesis (hi′dro-poy-e′sis, hid′ro-)

The formation of sweat. [hidro- + G. poiesis, formation]

hidroschesis
hidroschesis (hi-dros′ke-sis, hid-ros′)

Suppression of sweating. [hidro- + G. schesis, a checking]

hidrosis
hidrosis (hi-dro′sis, hi-)

The production and excretion of sweat. [G. hidros, sweat, + -osis, condition]

hidrotic
hidrotic (hi-drot′ik, hi-)

Relating to or causing hidrosis.

hierarchy
hierarchy (hi′er-ar-ke, hi-rar′ke)

1. Any system of persons or things ranked one above the other. 2. In psychology and psychiatry, an organization of habits or concepts in which simpler components are combined to form increasingly complex integrations. [G. hierarchia, rule or power of the high priest]
dominance h. a social situation in which one organism dominates all below it, the next all below it, and so on down to the organism dominated by all; e.g., the pecking order in apes, seals, barnyard hens, and other species.
Maslow h. a ranking of needs which humans presumably fills successively in the order of lowest to highest: physiological needs, love and belonging, self-esteem, and self-actualization.
response h. alternative reactions or modes of adjustment to a given situation arranged in the probable order of prior effectiveness; e.g., a mother attempting to discipline an unruly child may first request, cajole, then plead, scold, and finally punish; her behaviors can be ordered along a response h. for further monitoring of effectiveness.
h. of terms in radiology, the semantic concept of using different terms to describe anatomic or pathologic structures versus the resultant diagnostic images.

hierophobia
hierophobia (hi′er-o-fo′be-a)

Morbid fear of religious or sacred objects. [G. hieros, holy, + phobos, fear]

hierotherapy
hierotherapy (hi′er-o-thar′a-pe)

Treatment of disease by prayer and religious practices. [G. hieros, holy, + therapeia, therapy]

Higashi
Higashi

Ototaka. Japanese physician. See Chédiak-H. disease, Chédiak-Steinbrinck-H. anomaly, Chédiak-Steinbrinck-H. syndrome.

Highmore
Highmore

Nathaniel, British anatomist, 1613–1685. See antrum of H., H. body.

Higoumenakia sign
Higoumenakia sign

See under sign.

hila
hila (hi′la)

Plural of hilum.

hilar
hilar (hi′lar)

Pertaining to a hilum.

hilitis
hilitis (hi-li′tis)

Inflammation of the lining membrane of any hilus.

Hill
Hill

Archibald V., English biophysicist and Nobel laureate, 1886–1977. See H. equation, H. plot, initial heat.

Hill
Hill

Austin Bradford, British medical statistician, 1897–1991. See H.'s criteria of evidence, under criterion.

Hill
Hill

Harold A., 20th century U.S. radiologist. See H.-Sachs lesion.

Hill
Hill

Sir Leonard Erskine, English physiologist, 1866-1952. See H. sign, H. phenomenon.

Hill
Hill

Lucius D., U.S. thoracic surgeon, *1921. See H. operation.

Hill
Hill

Robert, British plant physiologist, *1899. See H. reaction.

Hillis
Hillis

David S., U.S. obstetrician-gynecologist, 1873–1942. See H.-Müller maneuver.

hillock
hillock (hil′lok)

In anatomy, any small elevation or prominence.
axon h. the conical area of origin of the axon from the nerve cell body; it contains parallel arrays of microtubules and is devoid of Nissl substance. SYN: implantation cone.
facial h. SYN: facial colliculus.
seminal h. SYN: seminal colliculus.

Hilton
Hilton

John, English surgeon, 1804–1878. See H. law, H. white line, H. method, H. sac.

hilum
hilum, pl .hila (hi′lum, hi′la) [TA]

1. The part of an organ where the nerves and vessels enter and leave. SYN: porta (1) . 2. A depression or slit resembling the h. in the olivary nucleus of the brain. [L. a small bit or trifle]
h. of dentate nucleus [TA] the mouth of the flasklike dentate nucleus of the cerebellum, directed inward, and giving exit to many of the fibers which compose the superior cerebellar peduncle or brachium conjunctivum. SYN: h. nuclei dentati [TA] .
h. of inferior olivary nucleus [TA] the medially oriented opening in the folded cell layer composing the inferior olivary nucleus through which the efferent fibers of the nucleus make their exit. SYN: h. nuclei olivaris inferioris [TA] .
h. of kidney [TA] the depression on the medial border of the kidney through which pass the segmental renal vessels and renal nerves and where the apex of the renal pelvis occurs. SYN: h. renalis [TA] , porta renis.
h. lienis splenic h..
h. of lung [TA] a wedge-shaped depression on the mediastinal surface of each lung, where the bronchus, blood vessels, nerves, and lymphatics enter or leave the viscus. SYN: h. pulmonis [TA] , porta pulmonis.
h. of lymph node [TA] the depressed area of the surface of a lymph node through which the efferent lymphatics emerge from the medulla and through which blood vessels enter and leave the node. SYN: h. nodi lymphatici [TA] .
h. nodi lymphatici [TA] SYN: h. of lymph node.
h. nuclei dentati [TA] SYN: h. of dentate nucleus.
h. nuclei olivaris inferioris [TA] SYN: h. of inferior olivary nucleus.
h. ovarii SYN: h. of ovary.
h. of ovary the depression along the mesovarian margin, at the insertion of the mesovarium, where vessels and nerves enter or leave the ovary. SYN: h. ovarii.
h. pulmonis [TA] SYN: h. of lung.
h. renalis [TA] SYN: h. of kidney.
h. of spleen SYN: splenic h..
splenic h. [TA] a fissure on the gastric surface of the spleen, giving passage to the splenic vessels and nerves. SYN: h. splenicum [TA] , h. lienis&star, h. of spleen, porta lienis.
h. splenicum [TA] SYN: splenic h..

hilus
hilus (hi′lus)

Former incorrect designation for hilum. [an Eng. variant of L. hilum]

himantosis
himantosis (hi-man-to′sis)

An unusually long uvula. [G. himas, strap, + -osis, condition]

hindbrain
hindbrain (hind′bran) [TA]

SYN: rhombencephalon.

hindgut
hindgut (hind′gut)

1. The caudal or terminal part of the embryonic gut. 2. Descending and sigmoid colon, rectum and anal canal; some include entire large intestine. SYN: endgut.

hindwater
hindwater (hind′wah-ter)

Colloquialism for amniotic fluid in utero behind the presenting part of the fetus.

hinge-bow
hinge-bow (hinj′bo)

SYN: face-bow.

Hinman
Hinman

Frank, Jr., U.S. urologist, *1915. See H. syndrome.

Hinton
Hinton

William A., U.S. physician, 1883–1959. See H. test, Mueller-H. agar.

hip
hip

1. The lateral prominence of the pelvis from the waist to the thigh. SYN: coxa (1) [TA] . 2. Head, neck, and greater and lesser trochanter of femur. It is this sense that is meant in the common phrases “h. fracture” or “h. replacement.” 3. More strictly, the h. joint. [A.S. hype]
snapping h. a condition in which the fascia lata or gluteus maximus muscle under tension, moving over the greater trochanter of the proximal end of the femur or the iliopsoas tendon moves over the lesser trochanter and causes a click.

hipberries
hipberries

SYN: rose hips.

Hippel
Hippel

Eugen von. See von H..

Hippelates
Hippelates (hip-e-la′tez)

The eye gnats, a genus of flies in the family Chloropidae (fruit flies) that are attracted to the body secretions and fluids of animals and humans, particularly those in the eyes. H. is suspected of transmitting certain types of conjunctivitis (such as pinkeye), bovine mastitis, and yaws (frambesia tropica). [G. h., driver of horses]

Hippobosca
Hippobosca (hip-o-bos′ka)

A genus of pupiparous louse flies (family Hippoboscidae) related to the tsetse flies; they are ectoparasites on birds and mammals. [G. hippos, horse, + boskein, to feed]

hippocampal
hippocampal (hip-o-kam′pal)

Relating to the hippocampus.

hippocampus
hippocampus (hip-o-kam′pus) [TA]

The complex, internally convoluted structure that forms the medial margin (“hem”) of the cortical mantle of the cerebral hemisphere, bordering the choroid fissure of the lateral ventricle, and composed of two gyri (Ammon horn and the dentate gyrus), together with their white matter, the alveus and fimbria hippocampi. In monkeys, apes, and humans the h. is confined to the temporal lobe by the massive development of the corpus callosum. Cytoarchitecturally a unique form of allocortex (archicortex), the h. forms part of the limbic system (formerly rhinencephalon). Its major afferent connections are with the entorhinal area of the parahippocampal gyrus, and transparent septum; by way of the fornix it projects to the septum, anterior nucleus of the thalamus, and mamillary body. SYN: h. major, major h.. [G. hippocampos, seahorse]
h. major SYN: h..
major h. SYN: h..
h. minor SYN: calcarine spur.
minor h. SYN: calcarine spur.

Hippocrates of Cos Hippocrates of Cos

Greek physician, called the “Father of Medicine,” circa 460–377 B.C. See hippocratic facies, hippocratic fingers, under finger, Hippocratic nails, under nail, hippocratic school, hippocratic succussion.

hippocratic hippocratic (hip-o-krat′ik)

Relating to, described by, or attributed to Hippocrates.

Hippocratic Oath Hippocratic Oath

An oath usually taken by physicians about to enter the practice of their profession, that, though usually attributed to Hippocrates of Cos, is probably an ancient oath of the Asclepiads. Its original form, now often revised, appears in a book of the Hippocratic collection as follows: “I swear by Apollo the physician, by Aesculapius, Hygeia, and Panacea, and I take to witness all the gods, all the goddesses, to keep according to my ability and my judgment the following Oath: To consider dear to me as my parents him who taught me this art; to live in common with him and if necessary to share my goods with him; to look upon his children as my own brothers, to teach them this art if they so desire without fee or written promise; to impart to my sons and the sons of the master who taught me and the disciples who have enrolled themselves and have agreed to the rules of the profession, but to these alone, the precepts and the instruction. I will prescribe regimen for the good of my patients according to my ability and my judgment and never do harm to anyone. To please no one will I prescribe a deadly drug, nor give advice which may cause his death. Nor will I give a woman a pessary to procure abortion. But I will preserve the purity of my life and my art. I will not cut for stone, even for patients in whom the disease is manifest; I will leave this operation to be performed by practitioners (specialists in this art). In every house where I come I will enter only for the good of my patients, keeping myself far from all intentional ill-doing and all seduction, and especially from the pleasures of love with women or with men, be they free or slaves. All that may come to my knowledge in the exercise of my profession or outside of my profession or in daily commerce with men, which ought not to be spread abroad, I will keep secret and will never reveal. If I keep this oath faithfully, may I enjoy my life and practice my art, respected by all men and in all times; but if I swerve from it or violate it, may the reverse be my lot.”

hippocratism hippocratism (hi-pok′ra-tizm)

A system of medicine, attributed to Hippocrates and his disciples, based on the imitation of nature's processes in the therapeutic management of disease.

hippurate
hippurate (hip′u-rat)

A salt or ester of hippuric acid.

hippuria
hippuria (hi-pu′re-a)

The excretion of an abnormally large amount of hippuric acid in the urine.

hippuric acid
hippuric acid (hi-pur′ik)

A detoxification and excretory product of benzoate found in the urine of humans and many herbivorous animals; used therapeutically in the form of its salts (hippurates of calcium and ammonium). [G. hippos, horse, + ouron, urine]

hippuricase
hippuricase (hi-pur′i-cas)

SYN: aminoacylase.

hippus
hippus (hip′us)

Intermittent pupillary dilation and constriction, independent of illumination, convergence, or psychic stimuli. [G. hippos, horse, from a fancied suggestion of galloping movements]
respiratory h. dilation of the pupils occurring during forced, voluntary inspiration, and contraction during expiration.

hirci hirci

Plural of hircus.

hircismus
hircismus (her-siz′mus)

Offensive odor of the axillae. [L. hircus, goat]

hircus
hircus, gen. and pl. hirci (her′kus, her′si)

1. The odor of the axillae. 2. [TA] SYN: axillary hairs, under hair. 3. SYN: tragus (1) . [L. he-goat]

Hirschberg
Hirschberg

Julius, German ophthalmologist, 1843–1925. See H. method.

Hirschfeld
Hirschfeld

Isador, U.S. dentist, 1881–1965. See H. canals, under canal.

Hirsch-Peiffer stain
Hirsch-Peiffer stain

See under stain.

Hirschsprung
Hirschsprung

Harald, Danish physician, 1830–1916. See H. disease.

hirsute
hirsute (her-soot′)

Relating to or characterized by hirsutism. [L. hirsutus, shaggy]

hirsuties
hirsuties (her-su′te-ez)

SYN: hirsutism. [Mod. L. fr. L. hirsutus, shaggy]

hirsutism
hirsutism (her′soo-tizm)

Presence of excessive bodily and facial hair, usually in a male pattern, especially in women; may be present in normal adults as an expression of an ethnic characteristic or may develop in children or adults as the result of androgen excess due to tumors or drugs, or nonandrogenetic drugs. SYN: hirsuties, pilosis. [L. hirsutus, shaggy]
constitutional h. mild to moderate degree of h. present in an individual exhibiting otherwise normal endocrine and reproductive function.
idiopathic h. h. of uncertain origin in women, who may additionally exhibit menstrual abnormalities and infertility.

hirtellous
hirtellous (hir′te-lus)

Having or resembling fine hairs; term describing the filamentous protein polysaccharide coating of microvilli. See glycocalyx. [L. hirtus, hairy, shaggy]

hirudicide
hirudicide (hi-roo′di-sid)

An agent that kills leeches. [L. hirudo, leech, + caedo, to kill]

hirudin
hirudin (hir′u-din)

An antithrombin substance extracted from the salivary glands of the leech that has the property of preventing coagulation of the blood. [L. hirudo, leech]

Hirudinea
Hirudinea (hir′oo-din′e-a)

The leeches, a class of worms (phylum Annelida) with flat, segmented bodies, a sucker at the posterior end, and often a smaller sucker at the anterior end; they are predatory on invertebrate tissues, or feed on blood and tissue exudates of vertebrates. [L. hirudo, leech]

hirudiniasis
hirudiniasis (hi-roo-di-ni′a-sis)

A condition resulting from leeches attaching themselves to the skin or being taken into the mouth or nose while drinking. [L. hirudo, leech, + G. -iasis, condition]

hirudinization
hirudinization (hi-roo′di-ni-za′shun)

1. The process of rendering the blood noncoagulable by the injection of hirudin. 2. The application of leeches.

Hirudo
Hirudo (hi-roo′do)

A genus of leeches (class Hirudinea, family Gnathobdellidae). Species previously used in medicine are: H. australis, Australian leech; H. decora, American leech; H. interrupta or H. troctina, a leech of northern Africa; H. medicinalis, speckled, Swedish, or German leech, the species previously in most general use; H. m. officinalis, a variety of the preceding; H. provincialis, the green or Hungarian leech; H. quinquestriata, five-striped leech. [L. leech]

His
His

Wilhelm, Jr., German physician, 1863–1934. See H. band, H. bundle, H. bundle electrogram, H. spindle, Kent-H. bundle, H.-Tawara system.

His
His

Wilhelm, Sr., Swiss anatomist and embryologist in Germany, 1831–1904. See H. copula, H. line, H. perivascular space, isthmus of H..

His&cbond;
His&cbond;, &cbond;His&cbond;

Symbol for histidyl.

&cbond;His
&cbond;His

Symbol for histidino.

His
His

Symbol for histidine.

Hiss
Hiss

Philip, U.S. bacteriologist, 1868–1913. See H. stain.

histaminase
histaminase (his-tam′i-nas)

SYN: amine oxidase (copper-containing).

histamine
histamine (H) (his′ta-men)

A vasodepressor amine derived from histidine by histidine decarboxylase and present in ergot and in animal tissues. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, and a vasodilator (capillaries and arterioles) that causes a fall in blood pressure. H., or a substance indistinguishable in action from it, is liberated in the skin as a result of injury. When injected intradermally in high dilution, it causes the triple response.
h. phosphate used in the treatment of certain allergies, cephalalgia, and acute multiple sclerosis with varying results; also used to test gastric secretory function, in the diagnosis of pheochromocytoma and in the treatment of Ménière disease; also available as h. acid phosphate.

histamine-fast
histamine-fast

Indicating the absence of the normal response to histamine, especially in speaking of true gastric anacidity.

histaminemia
histaminemia (his′ta-mi-ne′me-a)

The presence of histamine in the circulating blood. [histamine + G. haima, blood]

histaminuria
histaminuria (his′ta-mi-noo′re-a)

The excretion of histamine in the urine. [histidine + G. ouron, urine]

histangic
histangic (his-tan′jik)

SYN: histoangic.

histidase
histidase (his′ti-das)

SYN: histidine ammonia-lyase.

histidinal
histidinal (his′ti-din-al)

The aldehyde analog of histidine (–CHO replacing –COOH).

histidinase
histidinase (his′ti-di-nas)

SYN: histidine ammonia-lyase.

histidine
histidine (H, His) (his′ti-den)

α-Amino-β-(4-imidazolyl)propionic acid;the l-isomer is a basic amino acid found in most proteins. It is a nutritionally essential amino acid in mammals.
h. ammonia-lyase an enzyme catalyzing deamination of l-h. to urocanate and ammonia; this enzyme is absent or deficient in individuals with histidinemia. SYN: histidase, histidinase, h. deaminase.
h. deaminase SYN: h. ammonia-lyase.
h. decarboxylase an enzyme catalyzing the pyridoxal-phosphate-dependent decarboxylation of l-h. to histamine and CO₂; thus, it plays a role in constriction of bronchial smooth muscle.

histidinemia
histidinemia (his′ti-di-ne′me-a) [MIM*235800]

A metabolic disorder characterized by speech defects, growth deficiency, and mild mental retardation in some patients; associated with elevation of blood histidine level and excretion of histidine and related imidazole metabolites in urine due to deficiency of histidine ammonia lyase or histidinase; autosomal recessive inheritance, caused by mutation in the histidinase gene (HIS) on chromosome 12q. [histidine + G. haima, blood, + -ia]

histidino
histidino (&cbond;His) (his′ti-din-o)

The radical of histidine produced by removal of a hydrogen from a nitrogen atom; prefixed by N^α, N^τ, or N^π.

histidinol
histidinol (his′ti-di-nol)

The alcohol analog of histidine (–COOH becomes –CH₂OH).

histidinuria
histidinuria (his′ti-di-noo′re-a)

Excretion of considerable amounts of histidine in the urine; frequently observed in later months of pregnancy, and in histidinemia.

histidyl
histidyl (His&cbond;) (his′ti-dil)

The acyl radical of histidine.

histio- histio-

Tissue, especially connective tissue. [G. histion, web (tissue)]

histioblast
histioblast (his′te-o-blast)

A tissue-forming cell. SYN: histoblast. [histio- + G. blastos, germ]

histiocyte
histiocyte (his′te-o-sit)

A tissue macrophage; the class includes hepatic Kupffer cells, alveolar macrophages, giant cells of granulomas, osteoclasts, and dermal Langerhans cells. These cells derive from precursors that normally reside in bone marrow but migrate through the bloodstream to egress into tissues for final differentiation. SYN: histocyte. [histio- + G. kytos, cell]
cardiac h. a large mononuclear cell found in connective tissue of the heart wall in inflammatory conditions, especially in the Aschoff body. The ovoid nucleus contains a central chromatin mass appearing as a wavy bar in longitudinal section. SYN: Anitschkow cell, Anitschkow myocyte, caterpillar cell.
sea-blue h. a h. containing cytoplasmic granules that stain bright blue with hematologic stains such as Wright-Giemsa; found in bone marrow and in the spleen, associated with hepatosplenomegaly and thrombocytopenic purpura and in other blood diseases.

histiocytoma
histiocytoma (his′te-o-si-to′ma)

A tumor composed of histiocytes. [histio- + G. kytos, cell, + -oma, tumor]
fibrous h. SYN: dermatofibroma. See dermatofibroma.
generalized eruptive h. a rare recurring generalized eruption in adults of flesh colored or erythematous papules remaining localized to the skin and consisting of dermal nodules of mononuclear histiocytes that do not stain for lipid. SYN: nodular non-X histiocytosis.
malignant fibrous h. a sarcoma of variable malignant potential, occurring most often in the extremities and retroperitoneum; often recurs locally after resection, less often metastasizes; shows partial fibroblastic and histiocytic differentiation with a variable storiform pattern, myxoid areas, and giant cells.

histiocytosis
histiocytosis (his′te-o-si-to′sis)

A generalized proliferation of histiocytes. SYN: histocytosis.
Langerhans cell h. a set of closely related disorders unified by a common proliferating element, the Langerhans cell. Three overlapping clinical syndromes are recognized: a single site disease (eosinophilic granuloma), a multifocal unisystem process (Hand-Schuller-Christian syndrome), and a multifocal, multisystem h. (Letter-Siwe syndrome.) Formerly this process was known as h. X. SYN: h. X.
lipid h. h. with cytoplasmic accumulation of lipid, either phospholipid (Niemann-Pick disease) or glucocerebroside (Gaucher disease).
malignant h. a rapidly fatal form of lymphoma, characterized by fever, jaundice, pancytopenia, and enlargement of the liver, spleen, and lymph nodes; the affected organs show focal necrosis and hemorrhage, with proliferation of histiocytes and phagocytosis of red blood cells.
nodular non-X h. SYN: generalized eruptive histiocytoma.
nonlipid h. SYN: Letterer-Siwe disease.
sinus h. with massive lymphadenopathy a chronic disease occurring in children and characterized by massive painless cervical lymphadenopathy due to distension of the lymphatic sinuses by macrophages containing ingested lymphocytes, and by capsular and pericapsular fibrosis. SYN: Rosai-Dorfman disease.
h. X SYN: Langerhans cell h..
h. Y SYN: verrucous xanthoma.

histiogenic
histiogenic (his′te-o-jen′ik)

SYN: histogenous.

histioid
histioid (his′te-oyd)

SYN: histoid.

histioma
histioma (his-te-o′ma)

SYN: histoma.

histionic
histionic (his-te-on′ik)

Relating to any tissue.

histo- histo-

Tissue. [G. histos, web (tissue)]

histoangic
histoangic (his-to-an′jik)

Relating to the structure of blood vessels, especially in terms of their function. SYN: histangic. [histo- + G. angeion, vessel]

histoblast
histoblast (his′to-blast)

SYN: histioblast.

histochemistry
histochemistry (his′to-kem′is-tre)

SYN: cytochemistry.

histocompatibility
histocompatibility (his′to-kom-pat-i-bil′i-te)

A state of immunologic similarity (or identity) that permits successful homograft transplantation.

histocyte
histocyte (his′to-sit)

SYN: histiocyte.

histocytosis
histocytosis (his′to-si-to′sis)

SYN: histiocytosis.

histodifferentiation
histodifferentiation (his′to-dif-er-en-she-a′shun)

The morphologic appearance of tissue characteristics during development.

histofluorescence
histofluorescence (his-to-flor-es′ens)

Fluorescence of the tissues under exposure to ultraviolet rays following the injection of a fluorescent substance or as a result of a natural fluorescing substance.

histogenesis
histogenesis (his-to-jen′e-sis)

The origin of a tissue; the formation and development of the tissues of the body. SYN: histogeny. [histo- + G. genesis, origin]

histogenetic
histogenetic (his-to-je-net′ik)

Relating to histogenesis.

histogenous
histogenous (his-toj′e-nus)

Formed by the tissues; e.g., the h. cells in an exudate arising from proliferation of the fixed tissue cells. SYN: histiogenic. [histo- + G. -gen, producing]

histogeny
histogeny (his-toj′e-ne)

SYN: histogenesis.

histogram
histogram (his′to-gram)

1. A graphic columnar or bar representation to compare the magnitudes of frequencies or numbers of items. 2. Graphical representation of the frequency distribution of a variable, in which rectangles are drawn with their bases on a uniform linear scale representing intervals, and their heights are proportional to the values within each of the intervals. [histo- + G. gramma, a writing]

histoid
histoid (his′toyd)

1. Resembling in structure one of the tissues of the body. 2. Sometimes used with reference to the histologic structure of a neoplasm derived from and consisting of a single, relatively simple type of neoplastic tissue that closely resembles the normal, as in certain fibromas and leiomyomas. SYN: histioid. [histo- + G. eidos, resemblance]

histoincompatibility
histoincompatibility (his′to-in′kom-pat-i-bil′i-te)

A state of immunologic dissimilarity of tissues sufficient to cause rejection of a homograft when tissue is transplanted from one individual to another; implies a difference in histocompatibility genes in donor and recipient.

histologic
histologic, histological (his-to-loj′ik, i-kal)

Pertaining to histology.

histologist
histologist (his-tol′o-jist)

One who specializes in the science of histology. SYN: microanatomist.

histology
histology (his-tol′o-je)

The science concerned with the minute structure of cells, tissues, and organs in relation to their function. See microscopic anatomy. SYN: microanatomy. [histo- + G. logos, study]
pathologic h. SYN: histopathology.

histolysis
histolysis (his-tol′i-sis)

Disintegration of tissue. [histo- + G. lysis, dissolution]

histoma
histoma (his-to′ma)

A benign neoplasm in which the cytologic and histologic elements are closely similar to those of normal tissue from which the neoplastic cells are derived. SYN: histioma. [histo- + G. -oma, tumor]

histometaplastic
histometaplastic (his′to-met-a-plas′tik)

Exciting tissue metaplasia.

histomorphometry
histomorphometry (his′to-mor-fom′e-tre)

The quantitative measurement and characterization of microscopical images using a computer; manual or automated digital image analysis typically involves measurements and comparisons of selected geometric areas, perimeters, length angle of orientation, form factors, center of gravity coordinates, as well as image enhancement. [histo- + G. morphe, shape, + metron, measure]

histone
histone (H) (his′ton)

One of a number of simple proteins (often found in the cell nucleus) that contains a high proportion of basic amino acids, are soluble in water, dilute acids, and alkalies, and are not coagulable by heat; e.g., the proteins associated with nucleic acids in the nuclei of plant and animal tissues. They constitute about half of the mass of the chromosomes of eukaryotic cells.

histonectomy
histonectomy (his-to-nek′to-me)

SYN: periarterial sympathectomy. [histo- + G. ektome, excision]

histoneurology
histoneurology (his-to-noo-rol′o-je)

SYN: neurohistology.

histonomy
histonomy (his-ton′o-me)

A law of the development and structure of the tissues of the body. [histo- + G. nomos, law]

histonuria
histonuria (his-to-noo′re-a)

The excretion of histone in the urine, as observed in certain instances of leukemia, febrile illnesses, and wasting diseases. [histone + G. ouron, urine]

histopathogenesis
histopathogenesis (his′to-path-o-jen′e-sis)

Abnormal embryonic development or growth of tissue. [histogenesis + pathogenesis]

histopathology
histopathology (his′to-pa-thol′o-je)

The science or study dealing with the cytologic and histologic structure of abnormal or diseased tissue. SYN: pathologic histology.

histophysiology
histophysiology (his′to-fiz-e-ol′o-je)

The microscopic study of tissues in relation to their functions.

Histoplasma capsulatum
Histoplasma capsulatum (his-to-plaz′ma kap-soo-la′tum)

A dimorphic fungus species of worldwide distribution that causes histoplasmosis in humans and other mammals; its ascomycetous state is Ajellomyces capsulatum. The organism's natural habitat is soil fertilized with bird and bat droppings, where it grows as a mold, fragments of which, following inhalation, produce the primary pulmonary infection; within the mammalian host tissues, inhaled mycelial fragments grow as uninuclear yeasts that reproduce by budding. This parasitic form may also be induced in the laboratory by culturing the mycelial phase at 37°C on a blood-enriched medium; growth reverts to the mycelial form when the temperature is below 37°C. H. var. duboisii causes a clinically distinct disease, African histoplasmosis, in which large yeast cells with thicker walls are found in tissues, in contrast to the small yeast cells of H. var. farciminosum, which causes epizootic lymphangitis. [histo- + G. plasma, something formed]

histoplasmin
histoplasmin (his′to-plas′min)

An antigenic extract of Histoplasma capsulatum, used in immunological tests for the diagnosis of histoplasmosis; also used in skin test surveys of populations to determine the geographic distribution of the fungus and to predict those that are endemic for histoplasmosis.

histoplasmoma
histoplasmoma (his′to-plaz-mo′ma)

An infectious granuloma caused by Histoplasma capsulatum.

histoplasmosis
histoplasmosis (his′to-plaz-mo′sis)

A widely distributed infectious disease caused by Histoplasma capsulatum and occurring occasionally in outbreaks; usually acquired by inhalation of spores of the fungus in soil dust and manifested by a self-limited pneumonia. In patients with emphysema, infection may be chronic and cause pulmonary fibrocavitary disease resembling tuberculosis; in immunosuppressed patients and, rarely, in normals, h. may cause disseminated disease of the reticuloendothelial system, which is manifested by fever, emaciation, splenomegaly, and leukopenia. SYN: Darling disease.
acute h. caused by inhalation of microconidia, resulting in illness ranging from flulike to the acute diffuse pneumonitis seen with heavy exposure. Often, following illness, lesions heal, leaving calcified nodules.
African h. a form of h. caused by the fungus Histoplasma capsulatum var. duboisii, observed only in tropical Africa; infection is manifest as chronic granulomatous lesions in bone, skin, and other organs.
chronic h. disease usually seen in patients with underlying abnormal lung parenchyma, particularly emphysema and bullous lung disease. The disease is indolent, characterized by cough and sputum production, and radiographically by gradual loss of lung volume.
chronic mediastinal h. mediastinal fibrosis caused by lymph node involvement by h.. Can cause a huge fibrotic mass involving many critical structures in the mediastinum.
disseminated h. widespread infection that involves many organs; occurs in infants and immunocompromised patients, such as those with AIDS.
presumed ocular h. subretinal neovascularization in the macular region associated with chorioretinal atrophy and pigment proliferation adjacent to the optic disk, and peripheral chorioretinal atrophy (“histo-spots”).

historadiography
historadiography (his′to-ra-de-og′ra-fe)

Radiography of tissue, specifically microscopic sections; usually microradiography.

historrhexis
historrhexis (his-to-rek′sis)

Breakdown of tissue by some agency other than infection. [histo- + G. rhexis, rupture]

histotome
histotome (his′to-tom)

SYN: microtome. [histo- + G. tome, cut]

histotomy
histotomy (his-tot′o-me)

SYN: microtomy.

histotope
histotope (his′to-top)

That part of the Class II major histocompatibility molecule that interacts with the T cell receptor. [histo- + -tope]

histotoxic
histotoxic (his-to-tok′sik)

Relating to poisoning of the respiratory enzyme system of the tissues.

histotroph
histotroph (his′to-trof)

The part of the nutrition of the embryo derived from cellular sources other than blood. Cf.:embryotroph, hemotroph.

histotrophic
histotrophic (his-to-trof′ik)

Providing nourishment for or favoring the formation of tissue. [histo- + G. trophe, nourishment]

histotropic
histotropic (his-to-trop′ik)

Attracted toward the tissues; denoting certain parasites, stains, and chemical compounds. [histo- + G. tropikos, turning]

histozoic
histozoic (his-to-zo′ik)

Living in the tissues outside of a cell body; denoting certain parasitic protozoa. [histo- + G. zoikos, relating to an animal]

histozyme
histozyme (his′to-zim)

SYN: aminoacylase.

hitchhiker
hitchhiker (hitch′hik-er)

A gene that has no selective advantage, or may even be harmful, but that nevertheless temporarily becomes widespread because it is closely linked and coupled with a highly advantageous gene that is strongly selected.

Hitzig
Hitzig

Eduard, German psychiatrist, 1838–1907. See H. girdle.

HIV
HIV

Abbreviation for human immunodeficiency virus.

HIV-1
HIV-1

Abbreviation for human immunodeficiency virus-1.

HIV-2
HIV-2

Abbreviation for human immunodeficiency virus-2. See human immunodeficiency virus.

hives
hives (hivz)

1. SYN: urticaria. 2. SYN: wheal.
giant h. SYN: angioedema.

hK3
hK3

Abbreviation for human glandular kallikrein 3.

HL-7
HL-7

Abbreviation for Health Level 7, a medical informatics standard that facilitates communication among different digital systems.

HLA
HLA

Abbreviation for human leukocyte antigens, under antigen.

HMB-45
HMB-45

An antibody to a premelanosome glycoprotein found to be present in melanomas and other tumors derived from melanocytes.

HME
HME

Abbreviation for human monocytic ehrlichiosis.

HMG
HMG, hMG

Abbreviation for human menopausal gonadotropin.

HMG-CoA
HMG-CoA

Abbreviation for β-hydroxy-β-methylglutaryl-CoA.

HMO
HMO

Abbreviation for hypothetical mean organism; health maintenance organization.

HMPAO
HMPAO

Abbreviation for hexametazime or hexamethylpropyleneamine oxime.

HMS
HMS

Abbreviation for hypothetical mean strain.

HN2
HN2

Symbol for nitrogen mustard. See nitrogen mustards, under mustard.

hnRNA
hnRNA

Abbreviation for heterogeneous nuclear RNA.

Ho
Ho

Symbol for holmium.

Hoagland sign
Hoagland sign

See under sign.

hoarse
hoarse (hors)

Having a noisy voice. [A.S. has]

hoarseness
hoarseness (hors′nes)

A noisy quality of the voice.

Hoboken
Hoboken

Nicholaus van, Dutch anatomist and physician, 1632–1678. See H. gemmules, under gemmule, H. nodules, under nodule, H. valves, under valve.

HOCA
HOCA

SYN: HOCM.

Hoche
Hoche

Alfred E., German psychiatrist, 1865–1943. See H. bundle, H. tract.

HOCM
HOCM

Abbreviation for high osmolar contrast medium. SYN: HOCA.

Hodge
Hodge

Hugh L., U.S. gynecologist, 1796–1873. See H. pessary.

Hodgkin
Hodgkin

Alan L., British physiologist and Nobel laureate, *1914. See Goldman-H.-Katz equation.

Hodgkin
Hodgkin

Thomas, British physician, 1798–1866. See H. disease, H.-Key murmur, non-H. lymphoma.

Hodgson
Hodgson

Joseph, British physician, 1788–1869. See H. disease.

hodoneuromere
hodoneuromere (ho-do-noo′ro-mer)

In embryology, obsolete term for a metameric segment of the neural tube with its pair of nerves and their branches. [G. hodos, path, + neuron, nerve, + meros, part]

hodophobia
hodophobia (ho-do-fo′be-a)

Morbid fear of traveling. [G. hodos, path, + phobos, fear]

<SMCAP>hoechst</SMCAP> 33258
hoechst 33258

A bisbenzimidazole dye employed in cytochemistry and fluorescence microscopy as a sensitive indicator of DNA in chromosomes, specifically constitutive heterochromatin.

Hoeppli
Hoeppli

Reinhard J.C., German parasitologist, 1893–1973. See Splendore-H. phenomenon.

hof
hof (hof)

The hollow in the cytoplasm of a cell that lodges the nucleus. [Ger. court]

Hofbauer
Hofbauer

J. Isfred I., U.S. gynecologist, 1878–1961. See H. cell.

Hoffa
Hoffa

Albert, German surgeon, 1859–1907. See H. operation.

Hoffman
Hoffman

August Wilhelm, German chemist, 1818–1892. See Frei-Hoffmann reaction, H. violet.

Hoffmann
Hoffmann

Friedrich (Fredericus), German physician, 1660–1742. Professor of Anatomy and Surgery at Halle, noted for clinical observations of a variety of infectious diseases.

Hoffmann
Hoffmann

Johann, German neurologist, 1857–1919. See H. muscular atrophy, H. phenomenon, H. reflex, H. sign, Werdnig-H. disease, Werdnig-H. muscular atrophy.

Hoffmann
Hoffmann

Moritz, German anatomist, 1622–1698. See H. duct.

Hofmann
Hofmann, Hofmann-Wellenhof

Georg von, Austrian bacteriologist, 1843–1890. See H. bacillus.

Hofmeister
Hofmeister

Franz von, German surgeon, 1867–1926. See H. operation, H.-Pólya anastomosis.

Hofmeister
Hofmeister

Franz, German biochemist, 1850–1922. See H. series, H. gastrectomy.

Hogben
Hogben

Lawrence, British mathematician, *1895. See H. number.

Hogness
Hogness

D.S., U.S. molecular biologist, *1925. See Grunstein-H. assay, H. box.

holandric
holandric (hol-an′drik)

Related to genes located on the Y chromosome. [G. holos, entire, + aner, human male]

holarthritic
holarthritic (hol-ar-thrit′ik)

Relating to holarthritis.

holarthritis
holarthritis (hol-ar-thri′tis)

Inflammation of all or a great number of the joints. [G. holos, entire, + arthron, joint, + -itis, inflammation]

Holden
Holden

Luther, English anatomist, 1815–1905. See H. line.

Holder Holder

See Virchow-H. angle.

hole in retina
hole in retina

A break in the continuity of the sensory retina, permitting separation between the retinal pigment epithelium and sensory retina.

holism
holism (ho′lizm)

1. The principle that an organism, or one of its actions, is not equal to merely the sum of its parts but must be perceived or studied as a whole. 2. The approach to the study of a psychological phenomenon through the analysis of a phenomenon as a complete entity in itself. Cf.:atomism. [G. holos, entire]

holistic
holistic (ho-lis′tik)

Pertaining to the characteristics of holism or h. psychologies.

Holl
Holl

Mortiz, Austrian surgeon, 1852–1920. See H. ligament.

Hollander
Hollander

Franklin, U.S. physiologist, 1899–1966. See H. test.

Hollenhorst
Hollenhorst

Robert W., U.S. ophthalmologist, *1913. See H. plaques, under plaque.

Holliday
Holliday

R. See H. junction, H. structure.

hollow
hollow (hol′o)

A concavity or depression.
Sebileau h. depression between the inferior aspect of the tongue and the sublingual glands.

Holmes
Holmes

Sir Gordon M., English neurologist, 1876–1965. See H.-Adie pupil, H.-Adie syndrome, Stewart-H. sign.

Holmes
Holmes

Oliver Wendell. American physician, 1809–1894, identified the mode of spread and control of puerperal fever,

Holmes
Holmes

Thomas, U.S. psychiatrist, *1918. See H.-Rahe questionnaire.

Holmes
Holmes

Walter Chapin, 1884–1932. See H. stain.

Holmgren
Holmgren

Alarik Frithiof, Swedish physiologist, 1831–1897. See H. wool test.

Holmgren
Holmgren

Emil A., Swedish histologist, 1866–1922. See Holmgrén-Golgi canals, under canal.

holmium
holmium (Ho) (hol′me-um)

An element of the lanthanide group, atomic no. 67, atomic wt. 164.93032. [L. Holmia, for Stockholm]

holo- holo-

Whole, entire, complete. [G. holos]

holoacardius
holoacardius (hol′o-a-kar′de-us)

A separate, grossly defective twin lacking a heart of its own, its blood supply being dependent on a shunt from the placental circulation of a more nearly normal twin; a placental parasitic twin or omphalosite. Cf.:acardius. [holo- + G. a- priv. + kardia, heart]
h. acephalus a h. also lacking a head.
h. amorphus a h. in which the body of the parasite is represented by only a shapeless mass. SEE ALSO: anideus.

holo-ACP synthase
holo-ACP synthase

An enzyme catalyzing transfer of the 4′-phosphopantetheinyl residue from coenzyme A to a serine of apo-ACP (acyl carrier protein) to form holo-ACP, releasing adenosine 3′,5′-bisphosphate; a required step if fatty acid biosynthesis is to function.

holoacrania
holoacrania (hol′o-a-kra′ne-a)

A congenital skull defect in which bones of the vault are absent. [holo- + G. a- priv. + kranion, skull]

holoanencephaly
holoanencephaly (hol′o-an-en-sef′a-le)

Complete absence of cranium and brain. [holo- + G. an- priv. + enkephalos, brain]

holoblastic
holoblastic (hol-o-blas′tik)

Denoting the involvement of the entire (isolecithal or moderately telolecithal) ovum in cleavage. [holo- + G. blastos, germ]

holocarboxylase synthetase
holocarboxylase synthetase (hol-o-kar-boks′il-as sen′the-tas)

One of several enzymes that biotinylate other proteins ( e.g., carboxylases); a deficiency of h. will result in organic acidemia.

holocephalic
holocephalic (hol′o-se-fal′ik)

Denoting a fetus with a complete head but having deficiencies in other body parts. [holo- + G. kephale, head]

holocord
holocord (hol′o-kord)

Relating to the entire spinal cord, extending from the cervicomedullary junction to the conus medullaris.

holocrine
holocrine (hol′o-krin)

See h. gland. [holo- + G. krino, to separate]

holodiastolic
holodiastolic (hol′o-di-a-stol′ik)

Relating to or occupying the entire diastolic period.

holoendemic
holoendemic (hol′o-en-dem′ik)

Endemic in the entire population, as trachoma in the villages of Saudi Arabia.

holoenzyme
holoenzyme (hol-o-en′zim)

A complete enzyme, i.e., apoenzyme plus coenzyme, cofactor, metal ion, and/or prosthetic group.

hologastroschisis
hologastroschisis (hol′o-gas-tros′ki-sis)

A congenital malformation in which a cleft extends the entire length of the abdomen. [holo- + G. gaster, belly, + schisis, cleaving]

hologram
hologram (hol′o-gram)

A three-dimensional image produced by wavefront reconstruction and recorded on a photographic plate. [holo- + G. gramma, something written]

holography
holography (ho-log′ra-fe)

The process of creating a hologram.

hologynic
hologynic (hol-o-jin′ik)

Related to characters manifest only in females. [holo- + G. gyne, woman]

holomastigote
holomastigote (hol-o-mas′ti-got)

Possessing flagella over the entire surface. [holo- + G. mastix, whip]

holometabolous
holometabolous (hol′o-me-tab′o-lus)

Pertaining to a member of the Holometabola, a series of insect orders in which complex or complete metamorphosis is found. [holo- + G. metabole, change]

holomiantic (infection)
holomiantic (infection) (hol′om-i-an-tik)

Infectious outbreak due to exposure of a group of persons to an agent that affects or is common to all members of the group. [holo + C. miantos, defiled, fr. miaino. to defile, + -ic]

holomorphosis
holomorphosis (hol′o-mor-fo′sis)

Rarely used term for attainment or reestablishment of physical wholeness. [holo- + G. morphosis, shaping]

holophytic
holophytic (hol-o-fit′ik)

Having a plantlike mode of obtaining nourishment; denoting certain photosynthesizing protozoans, e.g., Euglena. [holo- + G. phyton, plant]

holoprosencephaly
holoprosencephaly (hol′o-pros-en-sef′a-le)

Presence of a single forebrain hemisphere or lobe; cycloplia occurs in the severest form. It is often accompanied by a deficit in median facial development. [holo- + G. proso, forward, + enkephalos, brain]

holoprotein
holoprotein (ho-lo-pro-ten)

A complete protein; I.E., apoprotein plus metal ion and/or prosthetic group.

holorachischisis
holorachischisis (hol′o-ra-kis′ki-sis)

Spina bifida of the entire spinal column. SYN: araphia, rachischisis totalis. [holo- + G. rhachis, spine, + schisis, fissure]

holoside
holoside (hol′o-sid)

A compound containing one or more identical, glycosidically linked carbohydrates.

holosystolic
holosystolic (hol′o-sis-tol′ik)

SYN: pansystolic.

holotelencephaly
holotelencephaly (hol′o-tel-en-sef′a-le)

Holoprosencephaly associated with arrhinencephaly. [holo- + telencephalon]

holothurins
holothurins (hol-o-thu′rins)

A class of highly toxic sulfated steroid glycosides secreted by sea cucumbers (Holothurioidea).

holotrichous
holotrichous (ho-lot′ri-kus)

Possessing cilia over the entire surface. [holo- + G. thrix, hair]

holozoic
holozoic (hol-o-zo′ik)

Animal-like in mode of obtaining nourishment, lacking photosynthetic capacity; denoting certain protozoans, in distinction to others that are holophytic. [holo- + G. zoon, animal]

Holt
Holt

Mary, 20th century English cardiologist. See H.-Oram syndrome.

Holter
Holter

Norman, U.S. biophysicist, 1914–1983. See H. monitor.

Holthouse
Holthouse

Carsten, British surgeon, 1810–1901. See H. hernia.

Holzknecht
Holzknecht

Guido, Austrian radiologist, 1872–1931. See H. unit.

homalocephalous
homalocephalous (hom′a-lo-sef′a-lus)

Having a flattened head. [G. homalos, level, + kephale, head]

Homalomyia
Homalomyia (hom′a-lo-mi′ya)

A genus of flies the larvae of which sometimes infect human or animal intestines. [G. homalos, even, + myia, a fly]

homaluria
homaluria (hom-a-loo′re-a)

Rarely used term for normal urine flow. [G. homalos, level, + ouron, urine]

Homans
Homans

John, U.S. surgeon, 1877–1954. See H. sign.

homatropine
homatropine (ho-mat′ro-pen)

An anticholinergic, mydriatic, and cycloplegic agent; available as the hydrobromide and the methylbromide. SYN: mandelytropine, tropine mandelate.

homaxial
homaxial (ho-mak′se-al)

Having all the axes alike, as a sphere. [G. homos, the same, + axis]

Home
Home

Sir Everard, English surgeon, 1756–1832. See H. lobe.

homeo- homeo-

The same, alike. SEE ALSO: homo- (1) . [G. homoios, similar]

homeobox
homeobox

A highly conserved DNA sequence of about 180 base pairs near the 3′ end of specific homeotic genes; it encodes a DNA-binding domain that allows the h. proteins to bind to and regulate gene expression in development. SYN: homeodomain.

homeodomain
homeodomain (ho′me-o-do- man′)

SYN: homeobox.

homeometric
homeometric (ho′me-o-met′rik)

Without change in size. [homeo- + G. metron, measure]

homeomorphous
homeomorphous (ho′me-o-mor′fus)

Of similar shape, but not necessarily of the same composition. [homeo- + G. morphe, shape]

homeopath
homeopath (ho′me-o-path)

SYN: homeopathist.

homeopathic
homeopathic (ho′me-o-path′ik)

1. Relating to homeopathy. SYN: homeotherapeutic (1) . 2. Denoting an extremely small dose of a pharmacologic agent that theoreticaly mimics the symptoms produced by the condition being treated, such as might be used in homeopathy; more generally, a dose believed to be too small to produce the effect usually expected from that agent. An alternative form of medicine to allopathic, in which drugs antagonize the effects of the disease. Cf.:pharmacologic (2) , physiologic (4) , supraphysiologic. [homeo- + G. pathos, disease]

homeopathist
homeopathist (ho-me-op′a-thist)

A medical practitioner of homeopathy. SYN: homeopath.

homeopathy
homeopathy (ho-me-op′a-the)

A system of therapy developed by Samuel Hahnemann based on the “law of similia,” from the aphorism, similia similibus curantur (likes are cured by likes), which holds that a medicinal substance that can evoke certain symptoms in healthy individuals may be effective in the treatment of illnesses having similar symptoms, if given in very small doses [homeo- + G. pathos, suffering]

homeoplasia
homeoplasia (ho′me-o-pla′ze-a)

The formation of new tissue of the same character as that already existing in the part. SYN: homoioplasia. [homeo- + G. plasis, a molding]

homeoplastic
homeoplastic (ho′me-o-plas′tik)

Relating to or characterized by homeoplasia.

homeorrhesis
homeorrhesis (ho′me-o-re′sis)

The set of processes by which imbalances and other defects in ontogeny are corrected before development is completed. SYN: ontogenic homeostasis, waddingtonian homeostasis. [homeo- + G. rheos, stream, current]

homeosis
homeosis (ho-me-o′sis)

Formation of a body part having characteristics normally found in a related or homologous part at another location in the body. [homeo- + G. -osis, condition]

homeostasis
homeostasis (ho′me-o-sta′sis, -os′ta-sis)

1. The state of equilibrium (balance between opposing pressures) in the body with respect to various functions and to the chemical compositions of the fluids and tissues. 2. The processes through which such bodily equilibrium is maintained. [homeo- + G. stasis, standing]
Bernard-Cannon h. the set of mechanisms responsible for the cybernetic adjustment of physiologic and biochemical states in postnatal life. SYN: physiologic h..
genetic h. SYN: Lerner h..
Lerner h. the restorative mechanisms that tend to correct perturbations in the genetic composition of a population. SYN: genetic h..
ontogenic h. SYN: homeorrhesis.
physiologic h. SYN: Bernard-Cannon h..
waddingtonian h. SYN: homeorrhesis.

homeostatic
homeostatic (ho′me-o-stat′ik)

Relating to homeostasis.

homeotherapeutic
homeotherapeutic (ho′me-o-thar-a-pu′tik)

1. SYN: homeopathic (1) . 2. Relating to homeotherapy.

homeotherapy
homeotherapy, homeotherapeutics (ho′me-o-thar′a-pe, -thar-a-pu′tiks)

Treatment or prevention of a disease using the principles of homeopathy.

homeotherm
homeotherm (ho′me-o-therm)

Any of the animals, including mammals and birds, that tend to maintain a constant body temperature. SYN: hematherm, warm-blooded animal. [homeo- + G. thermos, warm]

homeothermal
homeothermal (ho′me-o-ther′mal)

SYN: homeothermic.

homeothermic
homeothermic (ho′me-o-ther′mik)

Pertaining to, or having the essential characteristic of, homeotherms. Cf.:poikilothermic, heterothermic. SYN: hemathermal, hemathermous, hematothermal, homeothermal, homoiothermal, homothermal, warm-blooded.

homeotic
homeotic (ho-me-ot′ik)

Pertaining to or characterized by homeosis.

homeotypical
homeotypical (ho′me-o-tip′i-kal)

Of or resembling the usual type.

homergy
homergy (hom′er-je)

Obsolete term for normal metabolism and its results. [G. homos, same, + ergon, work]

homicidal
homicidal (hom-i-si′dal)

Having a tendency toward homicide.

homicide
homicide (hom′i-sid)

The killing of one human being by another. [L. homo, man, + caedo, to kill]

homidium bromide
homidium bromide (ho-mid′e-um)

A trypanocide used in veterinary medicine. SYN: ethidium.

Hominidae
Hominidae (ho-min′i-de)

The primate family, which includes modern humans (Homo sapiens) and several fossil groups.

Hominoidea
Hominoidea (hom-i-noy′de-a)

A superfamily of the Primates including the anthropoid apes and humans. Divided into the families Pongidae (anthropoid apes) and Hominidae (humans). [L. homo (homin-), man, + G. eidos, form]

Homo
Homo (ho′mo)

The genus of primates that includes humans. [L. man]
H. sapiens modern human beings. [L. wise man]

homo- homo-

1. Combining form meaning the same, alike; opposite of hetero-. SEE ALSO: homeo-. 2. In chemistry, prefix used to indicate insertion of one more carbon atom in a chain ( i.e., insertion of a methylene moiety). [G. homos, the same]

homoarginine
homoarginine (Har) (ho-mo-ar′ji-nen)

A homolog of arginine having an additional methylene group.

homobiotin
homobiotin (ho-mo-bi′o-tin)

A compound resembling biotin except for the substitution of an oxygen atom for the sulfur and the presence of an additional CH₂ group in the side chain; an active biotin antagonist.

homoblastic
homoblastic (ho-mo-blas′tik)

Developing from a single type of tissue. [homo- + G. blastos, germ]

homocarnosine
homocarnosine (ho-mo-kar′no-sen)

N²-(4-Aminobutyryl)-l-histidine;a constituent of the brain formed from l-histidine and γ-aminobutyric acid.

homocarnosinosis
homocarnosinosis (ho-mo-kar′no-sen-o-sis)

An inborn error in metabolism in which homocarnosine levels are elevated, particularly in the cerebral spinal fluid.

homocentric
homocentric (ho′mo-sen′trik)

Having the same center; denoting rays that meet at a common focus. Cf.:heterocentric (1) .

homochronous
homochronous (ho-mok′ro-nus)

1. SYN: synchronous. 2. Occurring at the same age in each generation. [homo- + G. chronos, time]

homocitrullinuria
homocitrullinuria (ho-mo-sit′ru-len-oor′e-a)

An inherited disorder associated with elevated urinary levels of homocitrulline.

homocladic
homocladic (ho-mo-klad′ik)

Denoting an anastomosis between branches of the same arterial trunk, as distinguished from heterocladic. [homo- + G. klados, a branch]

homocysteine homocysteine (Hcy) (ho-mo-sis′te-en, - sis′tin)

HSCH₂CH₂CH(NH₃)+COO-;a homolog of cysteine, produced by the demethylation of methionine, and an intermediate in the biosynthesis of l-cysteine from l-methionine via l-cystathionine. Elevated levels of h. have been associated with certain forms of heart disease. SEE ALSO: folic acid.Elevation of the level of h. in the plasma is an independent risk factor for cardiovascular disease (including myocardial infarction, stroke, thromboembolic disease, and intermittent claudication) and (in pregnant women) for fetal neural tube defects such as spina bifida and anencephaly. An increased plasma total h. level has been reported to confer an independent risk of vascular disease similar to that of smoking or hyperlipidemia, and to compound the risk associated with smoking and hypertension. Approximately 25% of people with atherosclerosis are found to have elevation of plasma h. above 15 mmol/L. Because h. rises after myocardial infarction and remains elevated for months, some have questioned the causal role assigned to it in vascular disease. Several prospective studies have failed to establish a connection between h. levels and coronary disease risk. H. appears to exert a direct toxic effect on the intima of arteries, besides inducing oxidation of low-density lipoproteins and predisposing to thrombus formation by activating platelets and coagulation factors. In animal reproduction studies it promotes neural tube defects, cardiac anomalies, and failure of ventral closure. Elevation of plasma h. occurs in various conditions, including genetic disorders, nutritional deficiencies, and chronic diseases. The level is higher in men and tends to rise with advancing age. Premature cardiovascular disease was first linked to elevation of h. in people with homocystinuria, a rare genetic disorder in which deficiency of the enzyme cystathionine β-synthase leads to elevation of h. in plasma and of its oxidation product, homocystine, in urine. A more common genetic disorder associated with abnormally high levels of h. results from mutation of the gene that encodes the enzyme methylene tetrahydrofolate reductase. The marked increase in h. levels after menopause may play a role in the increased incidence of vascular disease, cancer, and osteoporosis in postmenopausal women. Dietary deficiency of folic acid, vitamin B₆ (pyridoxine), and vitamin B₁₂ is also associated with elevation of h., as are chronic renal failure, hypothyroidism, and some malignancies. Lowering the serum concentration of h. by administration of folic acid has been shown to reduce the risk of adverse cardiovascular events in people with homocystinuria. In animal studies, administration of folic acid prevents the teratogenic effect of h.. Screening for elevated h. levels is advised for people with coronary artery disease out of proportion to known risk factors, or for those with a family history of premature atherosclerotic disease. Administration of folic acid in a dose of 1 mg/day or more reduces h. levels nearly to normal and protects against both vascular disease and birth defects.

homocystine
homocystine (ho-mo-sis′ten)

The disulfide resulting from the mild oxidation of homocysteine; an analog of cystine.

homocystinemia
homocystinemia (ho′mo-sis-ti-ne′me-a)

Presence of an excess of homocystine in the plasma, as in homocystinuria.

homocystinuria
homocystinuria (ho′mo-sis-ti-noo′re-a) [MIM*236200]

A metabolic disorder characterized by sparse blond hair, long limbs, pectus excavatum, dislocation of lens, failure to thrive, mental retardation, psychiatric disturbances, and thromboembolic episodes; some patients have alleviation of symptoms with pyridoxine while others are not responsive; associated with increased urinary excretion of homocystine and methionine. Autosomal recessive inheritance, but carriers have an increased risk of occlusive vascular disease; caused by mutation in the cysthathione beta-synthase gene (CBS) on chromosome 21q. In addition, there are seven other causes of h.: (1) defect in vitamin B12 metabolism [MIM*277400], (2) deficiency of N-methylene-tetrahydrofolate reductase [MIM*236250], (3) selective intestinal malabsorption of vitamin B12 [MIM*261100], (4) vitamin B12 responsive h., cblE type [MIM*236270], (5) methylcobalamin deficiency, cblG type [MIM*250940], (6) vitamin B12 metabolic defect type 2 [MIM*277410], and (7) transcobalamin II deficiency [MIM*275350].

homocytotropic
homocytotropic (ho′mo-si′to-trop′ik)

Having an affinity for cells of the same or a closely related species. [homo- + G. kytos, cell, + trope, a turning toward]

homodont
homodont (ho′mo-dont)

Having teeth all alike in form, as those of the lower vertebrates, in contrast to heterodont. [homo- + G. odous, tooth]

homodromous
homodromous (ho-mod′ro-mus)

Moving in the same direction. [homo- + G. dromos, running]

homoeo- homoeo-

See homeo-.

homoerotism
homoerotism, homoeroticism (ho-mo-er′o-tizm, -e-rot′i-sizm)

SYN: homosexuality. [homo- + G. eros, love]

homogametic
homogametic (ho′mo-ga-met′ik)

Producing only one type of gamete with respect to sex chromosomes; in humans and most animals, the female is h.. SYN: monogametic. [homo- + G. gametikos, connubial]

homogamy
homogamy (ho-mog′a-me)

Similarity of husband and wife in a specific trait. [homo- + G. gamos, marriage]

homogenate
homogenate (ho-moj′e-nat)

Tissue ground into a creamy consistency in which the cell structure is disintegrated (so-called “cell-free”). Cf.:brei.

homogeneous
homogeneous (ho-mo-je′ne-us)

Of uniform structure or composition throughout. [homo- + G. genos, race]

homogenesis
homogenesis (ho-mo-jen′e-sis)

Production of offspring similar to the parents, in contrast to heterogenesis. SYN: homogeny. [homo- + G. genesis, production]

homogenization
homogenization (ho-moj′e-ni-za′shun)

The process by which a material is made homogeneous.

homogenize
homogenize (ho-moj′e-niz)

To make homogeneous.

homogenous
homogenous (ho-moj′e-nus)

Having a structural similarity because of descent from a common ancestor. Commonly confused with homogeneous. [homo- + G. genos, family, kind]

homogentisate 1,2-dioxygenase
homogentisate 1,2-dioxygenase (ho-mo-jen′tis-at)

An iron-containing enzyme that catalyzes the oxidative cleavage of the benzene ring in homogentisic acid by O₂, forming 4-maleylacetoacetate; an absence or deficiency of this enzyme will result in alcaptonuria. SYN: homogentisic acid oxidase.

homogentisic acid
homogentisic acid (ho′mo-jen-tis′ik)

Glycosuric acid; (2,5-dihydroxyphenyl)acetic acid;an intermediate in l-phenylalanine and l-tyrosine catabolism; if made alkaline, it oxidizes rapidly in air to a quinone that polymerizes to a melaninlike material; elevated levels are observed in individuals having alcaptonuria. SYN: alcapton, alkapton.
h. oxidase SYN: homogentisate 1,2-dioxygenase.

homogeny
homogeny (ho-moj′e-ne)

SYN: homogenesis.

homoglycan
homoglycan (ho-mo-gli′kan)

A polysaccharide consisting of only one type of monosaccharide subunit ( e.g., glucan). Cf.:heteroglycan, glycan.

homograft
homograft (ho′mo-graft)

SYN: allograft.

homoioplasia
homoioplasia (ho′moy-o-pla′ze-a)

SYN: homeoplasia.

homoiothermal
homoiothermal (ho-moy-o-ther′mal)

SYN: homeothermic.

homokaryon
homokaryon (ho-mo-kar′e-on)

Genetically identical multiple nuclei in a common cytoplasm, usually resulting from fusion of two cells from the same species. [homo- + G. karyon, kernel, nut]

homokaryotic
homokaryotic (ho′mo-kar-e-ot′ik)

Exhibiting the properties of a homokaryon.

homokeratoplasty
homokeratoplasty (ho′mo-ker′a-to-plas-te)

Corneal transplant between members of the same species.

homolateral
homolateral (ho-mo-lat′er-al)

SYN: ipsilateral. [homo- + L. latus, side]

homolipids
homolipids (ho-mo-lip′idz)

Lipids containing only C, H, and O. Cf.:heterolipids. SYN: simple lipids.

homolog
homolog, homologue (hom′o-log)

A member of a homologous pair or series. [homo- + G. logos, word, ratio, relation]

homologous
homologous (ho-mol′o-gus)

Corresponding or alike in certain critical attributes. 1. In biology or zoology, denoting organs or parts corresponding in evolutionary origin and similar to some extent in structure, but not necessarily similar in function. 2. In chemistry, denoting a single chemical series, differing by fixed increments. 3. In genetics, denoting chromosomes or chromosome parts identical with respect to their construction and genetic content. 4. In immunology, denoting serum or tissue derived from members of a single species, or an antibody with respect to the antigen that produced it. 5. Proteins having identical or similar functions (particularly with respect to proteins from different species). [see homolog]

homology
homology (ho-mol′o-je)

The state of being homologous.
h. of chains the degree of similarity between the base sequences of strands of two DNAs. SYN: h. of strands.
DNA h. the degree (or percentage) of hybridization capable between the DNA of different microorganisms.
h. of strands SYN: h. of chains.

homolysin
homolysin (ho-mol′i-sin)

A sensitizing hemolytic antibody (hemolysin) formed as the result of stimulation by an antigen derived from an animal of the same species. [homo- + hemolysin]

homolysis
homolysis (ho-mol′i-sis)

Lysis of red blood cells by a homolysin and complement.

homomorphic
homomorphic (ho-mo-mor′fik)

Denoting two or more structures of similar size and shape. [homo- + G. morphe, shape, appearance]

homonomous
homonomous (ho-mon′o-mus)

Denoting parts, having similar form and structure, arranged in a series, as the fingers or toes. [G. homonomos, under the same laws, fr. homos, same, + nomos, law]

homonomy
homonomy (ho-mon′o-me)

The condition of being homonomous.

homonuclear
homonuclear (ho-mo-noo′kle-er)

Denoting a cell line that retains the original chromosome complement.

homonymous
homonymous (ho-mon′i-mus)

Having the same name or expressed in the same terms, e.g., the corresponding halves (right or left, superior or inferior) of the retinas. [G. h., of the same name, fr. onyma, name]

homophenes
homophenes (ho′mo-fenz)

Words in which the visible organs of speech behave the same, e.g., tug, tongue, tuck.

homophil
homophil (ho′mo-fil)

Denoting an antibody that reacts only with the specific antigen which induced its formation. [homo- + G. philos, fond]

homophobia
homophobia (ho-mo-fo′be-a)

Irrational fear of homosexual feelings, thoughts, behaviors, or persons.
internalized h. h. occurring in a homosexual person, often associated with self-loathing, self-censure, and self-censorship.

homoplastic
homoplastic (ho-mo-plas′tik)

Similar in form and structure, but not in origin. [homo- + G. plastos, formed]

homopolymer
homopolymer (ho-mo-pol′i-mer)

A polymer composed of a series of identical moieties; e.g., polylysine, poly(adenylic acid), polyglucose.

homoproline
homoproline (ho-mo-pro′len)

SYN: pipecolic acid.

homoprotocatechuic acid
homoprotocatechuic acid (ho′mo-pro′to-kat-e-choo′ik)

(3,4-Dihydroxyphenyl)acetic acid;an isomer of homogentisic acid found in urine; a degradation product of l-tyrosine, l-dopa, and hydroxytyramine.

homorganic
homorganic (hom-or-gan′ik)

Produced by the same organs, or by homologous organs.

homosalate
homosalate (ho-mo-sal′at)

An ultraviolet screening agent for topical application to the skin.

homoscedasticity
homoscedasticity (ho′mo-ske-das-tis′i-te)

Constancy of the variance of a measure over the levels of the factor under study.

homoserine
homoserine (ho-mo-ser′en)

Amino-4-hydroxybutyric acid;a hydroxyamino acid differing from serine in the possession of an additional CH₂ group. An intermediate in the biosynthesis of cystathionine, threonine, and methionine.
h. deaminase SYN: cystathionine γ-lyase.
h. dehydratase SYN: cystathionine γ-lyase.
h. lactone the cyclic ester ( i.e., the δ-lactone) of h.; formed by the reaction of cyanogen bromide on methionyl residues in peptides and proteins.

homosexual
homosexual (ho-mo-sek′shoo-al)

1. Relating to or characteristic of homosexuality. 2. One whose interests and behavior are characteristic of homosexuality. See gay, lesbian.

homosexuality
homosexuality (ho′mo-sek-shoo-al′i-te)

Erotic attraction or activity, including sexual congress, between individuals of the same sex, especially past puberty. SYN: homoerotism, homoeroticism.
ego-dystonic h. a psychological or psychiatric disorder in which an individual experiences persistent distress associated with same-sex preference and a strong need to change the behavior or, at least, to alleviate the distress associated with the h.; no longer a DSM-recognized diagnosis; now included under sexual disorder, not otherwise specified.
female h. erotic predisposition, or activity, including sexual congress, between two women past the age of puberty.
latent h. an erotic inclination toward members of the same sex not consciously experienced or expressed in overt action, as opposed to overt h. Use of this term is disappearing because of both its potentially iatrogenic effect and the inability to validate the phenomenon by techniques outside of psychoanalytic theory. SYN: unconscious h..
male h. erotic predisposition, or activity, including sexual congress, between two men, past the age of puberty.
overt h. homosexual inclinations consciously experienced and expressed in actual homosexual behavior.
unconscious h. SYN: latent h..

homosteroid
homosteroid

A steroid that has had at least one of the rings in its structure expanded.

4-homosulfanilamide
4-homosulfanilamide (ho′mo-sul-fa-nil′a-mid)

SYN: mafenide.

homothallic
homothallic (ho-mo-thal′ik)

In fungi, denoting a kind of sexual reproduction in which a nucleus of a thallus is capable of fusing with another nucleus from the same thallus or mating type. Cf.:heterothallic. [homo- + G. thallos, a young shoot]

homothermal
homothermal (ho-mo-ther′mal)

SYN: homeothermic. [homo- + G. therme, heat]

homotonic
homotonic (ho-mo-ton′ik)

Of uniform tension or tonus.

homotopic
homotopic (ho-mo-top′ik)

Pertaining to or occurring at the same place or part of the body. [homo- + G. topos, place]

homotransplantation
homotransplantation (ho′mo-tranz-plan-ta′shun)

SYN: allotransplantation.

homotropic
homotropic (ho-mo-tro-pik)

Referring to the binding of the same ligand to a macromolecule; E.G., the binding of four O₂ to hemoglobin is h. cooperativity.

homotype
homotype (ho′mo-tip)

Any part or organ of the same structure or function as another, especially as one on the opposite side of the body. [homo- + G. typos, type]

homotypic
homotypic, homotypical (ho-mo-tip′ik, i-kal)

Of the same type or form; corresponding to the other one of two paired organs or parts.

homovanillic acid
homovanillic acid (HVA) (ho′mo-va-nil′ik)

4-Hydroxy-3-methoxyphenylacetic acid;a phenol found in human urine; produced through the methylation of homoprotocatechuic acid on the meta-OH group. It is the principal urinary metabolite of dopa and dopamine.

homozoic
homozoic (ho-mo-zo′ik)

Relating to the same animal or the same species of animal. [homo- + G. zoikos, relating to an animal]

homozygosity
homozygosity, homozygosis (ho′mo-zi-gos′i-te, -zi-go′sis)

The state of being homozygous. [homo- + G. zygon, yoke]

homozygote
homozygote (ho-mo-zi′got)

A homozygous individual. [homo- + G. zygotos, yoke]

homozygous
homozygous (ho-mo-zi′gus)

Having identical alleles at one or more loci.

homozygous by descent
homozygous by descent

Possessing two identical alleles at a given locus that are descended from a single source, as may occur in consanguineous mating.

homunculus
homunculus (ho-mungk′u-lus)

1. An exceedingly minute body which, according to the views of development held by some medical scientists of the 16th and 17th centuries, was contained in a sex cell. From this preformed but infinitely small structure the human body was thought to be developed. SEE ALSO: preformation theory, animalcule. 2. The figure of a human sometimes superimposed on pictures of the surface of the brain to represent the motor or sensory regions of the body represented there. [L. dim. of homo, man]

Honduras bark
Honduras bark (hon-doo′ras)

SYN: cascara amara.

honey
honey (hon′e)

Clarified h., a saccharine substance deposited in the honeycomb by the honeybee, Apis mellifera; used as an excipient, as a flavor in gargles and cough remedies, and as a food. SYN: mel (1) . [A.S. hunig]

honk
honk (hawnk)

1. In medical terms, a sound that can be likened to the call of a goose. 2. Sometimes specifically used to denote a sound of laryngeal origin made by vocal cords vibrating in a forced expiration because of a congenital vascular ring compressing the trachea. [echoic]
systolic h. a somewhat musical systolic murmur likened to the honking of a goose; sometimes of innocent but unexplained origin, at other times a sign of mitral insufficiency. SYN: systolic whoop.

hood
hood (hud)

1. The anterior part of the integument of soft ticks (family Argasidae) that extends over the capitulum and forms the roof of the camerostome. 2. An expanded, covering structure that resembles the h. of robe or cloak in shape or function, such as the extensor digital expansions that overly the dorsal aspect of the heads of the metacarpals. [O.E. hod, hat]
dorsal h. SYN: extensor digital expansion.

hook
hook (huk)

1. An instrument curved or bent near its tip, used for fixation of a part or traction. 2. hamulus. [A.S. hok]
calvarial h. an instrument used in prying off the top of the skull after it has been sawed around, at autopsies and dissections.
h. of hamate a hooklike process on the distal and medial part of the palmar surface of the hamate bone. SYN: hamulus ossis hamati [TA] .
palate h. an instrument for pulling forward the soft palate in order to facilitate posterior rhinoscopy.
sliding h. a movable attachment used on an orthodontic wire for the application of elastic traction or headgear force.
h. of spiral lamina SYN: hamulus of spiral lamina.
squint h. a surgical instrument used to lift ocular muscles.
tracheotomy h. right-angled h. used in holding the trachea steady during tracheotomy.

Hooke
Hooke

Robert, British experimental physicist, 1635–1703. See hookean behavior, H. law.

hooklets
hooklets (huk′letz)

1. Clawlike, retractile chitinous hooks that encircle or line the rostellum of the scolex of certain taenioid tapeworms for attachment to the intestinal mucosa, with the additional aid of suckers; the h. can be withdrawn and the rostellum inverted when the tapeworm moves. Various arrangements and forms of the h. characterize the families of taenioid cestodes. 2. H. of degenerated scoleces of Echinococcus species in the fluids of the hydatid cyst. 3. The h. of the oncosphere, by which it claws out of its membrane sheath after hatching and penetrates the host gut wall; these h. can later be found in the cercomer of the procercoid or cysticercoid.

hookworm
hookworm (huk′werm)

Common name for bloodsucking nematodes of the family Ancyclostomatidae, chiefly members of the genera Ancylostoma (the Old World h.), Necator, and Uncinaria, and including the species A. caninum (dog h.) and N. americanus (New World h.).

Hoover
Hoover

Charles F., U.S. physician, 1865–1927. See H. signs, under sign.

Hopkins
Hopkins

Sir Frederick G., English biochemist and Nobel laureate, 1861–1947. See Benedict-H.-Cole reagent.

Hopkins
Hopkins

H. H., 20th century Br. optical physicist. See H. rod-lens telescope.

Hoplopsyllus anomalus
Hoplopsyllus anomalus (hop-lo-sil′us a-nom′a-lus)

A species of flea parasitic on ground squirrels of the western U.S., and a vector of plague. [G. hoplo, tool, weapon, + psyll, flea]

Hopmann
Hopmann

Carl M., German rhinologist, 1849–1925. See H. papilloma, H. polyp.

hops
hops

SYN: humulus.

hor. decub.
hor. decub.

Abbreviation for L. hora decubitus, at bedtime.

hordenine
hordenine (hor′den-en)

A biogenic amine first isolated from barley; increases blood pressure. [L. hordeum, barley, + -in]

hordeolum
hordeolum (hor-de′o-lum)

A suppurative inflammation of a gland of the eyelid. [Mod. L., hordeolus, a sty in the eye, dim. of hordeum, barley]
h. externum inflammation of the sebaceous gland of an eyelash. SYN: sty, stye.
h. internum an acute purulent infection of a meibomian (tarsal) gland. SYN: acute chalazion, h. meibomianum, meibomian sty.
h. meibomianum SYN: h. internum.

Horecker
Horecker

Bernard L., U.S. biochemist, *1914. See Warburg-Dickens-H. shunt.

horehound
horehound, hoarhound (hor-hound)

Marrubium vulgare (family Labitae); bitter principle is marrubium, a volatile oil. A compound alleged to have expectorant properties and often found in cough drops and other patent medicines. [O.E. har, hoary, + hune, herb]

horizontalis
horizontalis (hor-i-zon-ta′lis)

Horizontal, referring to the plane of the body, perpendicular to the vertical plane, at right angles both to the median and coronal planes, that separates the body into upper and lower parts. [L.]

hormesis
hormesis (hor-me′sis)

The stimulating effect of subinhibitory concentrations of any toxic substance on any organism. [Gr. h., rapid motion]

hormion
hormion (hor′me-on)

A craniometric point at the junction of the posterior border of the vomer with the sphenoid bone. [G. hormos, cord, chain, necklace]

hormogonal
hormogonal (hor-mo′go-nal)

Referring to a class of Cyanobacteria in which the cells grow in filaments.

hormonal
hormonal (hor-mon′al)

Pertaining to hormones.

hormone
hormone (hor′mon)

A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part; depending on the specificity of their effects, hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them. A number of hormones are formed by ductless glands, but secretin, cholecystokinin, and pancreozymin, formed in the gastrointestinal tract, by definition are also hormones. For hormones not listed below, see specific names. [G. hormon, pres. part. of hormao, to rouse or set in motion]
adipokinetic h. SYN: adipokinin.
adrenal androgen-stimulating h. (AASH) a putative pituitary h. that may be responsible for increased secretion of adrenal androgens at the time of puberty.
adrenocortical hormones hormones secreted by the human adrenal cortex; e.g., cortisol, aldosterone, corticosterone.
adrenocorticotropic h. (ACTH) the h. of the anterior lobe of the hypophysis that governs the nutrition and growth of the adrenal cortex, stimulates it to functional activity, and also possesses extraadrenal adipokinetic activity; it is a polypeptide containing 39 amino acids, but exact structure varies from one species to another; sometimes prefixed by α to distinguish it from β-corticotropin. The first 13 amino acids at the N-terminal region are identical to α-melanotropin. SYN: adrenocorticotropin, adrenotropic h., adrenotropin, corticotropic h., corticotropin (1) .
adrenomedullary hormones hormones produced by the adrenal medulla, particularly the catecholamines epinephrine and norepinephrine.
adrenotropic h. SYN: adrenocorticotropic h..
androgenic h. any h. that produces a masculinizing effect; of the naturally occurring androgenic hormones, testosterone is the most potent.
antidiuretic h. (ADH) SYN: vasopressin.
anti-müllerian h. SYN: müllerian inhibiting substance.
cardiac h. SYN: herz h..
chorionic gonadotropic h., chorionic gonadotrophic h. SYN: chorionic gonadotropin.
chorionic “growth h.-prolactin” (CGP) SYN: human placental lactogen.
cortical hormones steroid hormones produced by the adrenal cortex.
corticotropic h. SYN: adrenocorticotropic h..
corticotropin-releasing h. (CRH) a factor secreted by the hypothalamus that stimulates the pituitary to release adrenocorticotropic h.. SYN: corticotropin-releasing factor.
ectopic h. a h. formed by tissue outside the normal endocrine site of production; e.g., adrenocorticotropic h. produced by a bronchogenic carcinoma. SYN: inappropriate h..
endocrine hormones hormones produced by the endocrine system. Cf.:tissue hormones.
erythropoietic h. 1. generally, any h. that promotes the formation of red blood cells, e.g., testosterone; 2. SYN: erythropoietin.
estrogenic h. SYN: estradiol.
follicle-stimulating h. (FSH) SYN: follitropin.
follicular h. SYN: estrone.
galactopoietic h. SYN: prolactin.
gametokinetic h. SYN: follitropin.
gastrointestinal h. any secretion of the gastrointestinal mucosa affecting the timing and quantity of various digestive secretions ( e.g., secretin) or causing enhanced motility of the target organ ( e.g., cholecystokinin).
gonadal hormones SYN: sex hormones.
gonadotropic h. SYN: gonadotropin.
gonadotropin-releasing h. (GnRH, GRH) SYN: gonadoliberin (1) .
growth h. (GH) SYN: somatotropin.
growth h.-inhibiting h. (GIH) SYN: somatostatin.
growth h.-releasing h. (GHRH, GH-RH) SYN: somatoliberin.
heart h. SYN: herz h..
herz h. a substance present in extracts of cardiac tissue that augments cardiac contraction; possibly adenosine, a catecholamine, or some nonspecific stimulant present generally in tissues. SYN: cardiac h., heart h..
human chorionic somatomammotropic h. (HCS) SYN: human placental lactogen.
hypophysiotropic h. a h. that stimulates the rate of secretion of hypophysial hormones; e.g., a releasing factor; hypothalamic (regulatory) factor.
inappropriate h. SYN: ectopic h..
interstitial cell-stimulating h. (ICSH) SYN: lutropin.
lactation h. SYN: prolactin.
lactogenic h. SYN: prolactin.
lipid-mobilizing h. SYN: lipotropin.
lipotropic h. (LPH) , lipotropic pituitary h. SYN: lipotropin.
local h. a metabolic product secreted by one set of cells that affects the function of nearby cells; an autacoid; e.g., prostaglandins and neurotransmitters.
luteinizing h. (LH) SYN: lutropin.
luteinizing h.-releasing h. (LH-RH, LRH) SYN: luliberin.
mammotropic h. SYN: prolactin.
melanocyte-stimulating h. (MSH) SYN: melanotropin.
melanotropin release-inhibiting h. (MIH) SYN: melanostatin.
melanotropin-releasing h. (MRH) SYN: melanoliberin.
neurohypophysial hormones hormones produced in the hypothalamus; E.G., oxytocin, vasopressin.
ovarian h. SYN: relaxin.
pancreatic hyperglycemic h. SYN: glucagon.
parathyroid h. (PTH) a peptide h. formed by the parathyroid glands; it raises the serum calcium levels when administered parenterally by causing bone resorption, reducing renal clearance of calcium and increasing efficiency of calcium absorption in the intestine. It acts in conjunction with calcitonin and other hormones. SYN: parathormone, parathyrin.
pituitary gonadotropic h. SYN: anterior pituitary gonadotropin.
pituitary growth h. SYN: somatotropin.
placental growth h. SYN: human placental lactogen.
pregnancy h. SYN: progesterone.
progestational h. SYN: progesterone.
proparathyroid h. the immediate precursor of parathyroid h.; proparathyroid differs from parathyroid h. by an N-terminal hexapeptide extension.
releasing h. (RH) SYN: releasing factors.
salivary gland h. SYN: parotin.
sex hormones a general term covering those steroid hormones that are formed by testicular, ovarian, and adrenocortical tissues, and that are androgens or estrogens. SYN: gonadal hormones.
somatotropic h. (STH) SYN: somatotropin.
somatotropin release-inhibiting h. (SIH) SYN: somatostatin.
somatotropin-releasing h. (SRH) SYN: somatoliberin.
steroid hormones those hormones possessing the steroid ring system; e.g., androgens, estrogens, adrenocortical hormones.
sympathetic h. SYN: sympathin.
thyroid-stimulating h. (TSH) SYN: thyrotropin.
thyrotropic h. SYN: thyrotropin.
thyrotropin-releasing h. (TRH) SYN: thyroliberin.
tissue hormones hormones synthesized by cells other than those in the endocrine system. Cf.:endocrine hormones.
tropic hormones, trophic hormones those hormones of the anterior lobe of the pituitary that affect the growth, nutrition, or function of other endocrine glands ( e.g., TRH, ACTH).
vertebrate hormones hormones synthesized in vertebrates.

hormonogenesis
hormonogenesis (hor′mo-no-jen′e-sis)

The formation of hormones. SYN: hormonopoiesis.

hormonogenic
hormonogenic (hor′mo-no-jen′ik)

Pertaining to the formation of a hormone. SYN: hormonopoietic.

hormonopoiesis
hormonopoiesis (hor′mo-no-poy-e′sis)

SYN: hormonogenesis. [hormone + G. poiesis, production]

hormonopoietic
hormonopoietic (hor′mo-no-poy-et′ik)

SYN: hormonogenic.

hormonoprivia
hormonoprivia (hor′mo-no-priv′e-a)

Obsolete term meaning partial or total deprivation of hormones. [hormone + G. privus, deprived of]

hormonotherapy
hormonotherapy (hor′mo-no-thar′a-pe)

Treatment with hormones.

horn
horn (horn) [TA]

Any structure resembling a h. in shape. SYN: cornu (1) . [A.S.]
Ammon h. [TA] one of the two interlocking gyri composing the hippocampus, the other being the dentate gyrus. Based on cytoarchitectural features, Ammon h. can be divided into region I [TA] (regio I cornus ammonis [TA]), region II [TA] (regio II cornus ammonis [TA]), region III [TA] (regio III cornus ammonis [TA]) and region IV [TA] (regio IV cornus ammonis [TA]). SYN: cornu ammonis. [G. Ammon, the Egyptian deity Amun]
anterior h. [TA] 1. the frontal or anterior division of the lateral ventricle of the brain, extending forward from Monro interventricular foramen; See lateral ventricle. 2. the anterior h. or ventral gray column of the spinal cord as appearing in cross section. The anterior h. is composed of the spinal lamina VIII-IV [TA] of Rexed with portions of VII also extending into its geographical boundaries in lumbosacral and cervical levels. The nuclei of the anterior h. are the anterolateral nucleus [TA] or ventrolateral nucleus [TAalt] (nucleus anterolateralis [TA]), anterior nucleus [TA] (nucleus anterior [TA]), anteromedial nucleus [TA] or ventromedial nucleus [TAalt], (nucleus anteromedialis [TA]), posterolateral nucleus [TA] or dorsolateral nucleus [TAalt] (nucleus posterolateralis [TA]), retroposterior lateral nucleus [TA] or retrodorsal lateral nucleus [TAalt] (nucleus retroposterolateralis [TA]), posteromedial nucleus [TA] or dorsomedial nucleus [TAalt] (nucleus posteromedialis [TA]), central nucleus [TA] (nucleus centralis [TA]) and the accessory nucleus and phrenic nucleus, both found in cervical levels only. SEE ALSO: anterior column, gray columns, under column. SYN: cornu anterius [TA] , ventral h..
cicatricial h. a keratinous h. projecting outward from a scar.
coccygeal h. SYN: coccygeal cornu.
cutaneous h. a protruding keratotic growth of the skin; the base may show changes of actinic keratosis or carcinoma. SYN: cornu cutaneum, warty h..
frontal h. [TA] See inferior h. of lateral ventricle, inferior h..
greater h. of hyoid bone [TA] the larger and more lateral of the two processes on either side of the hyoid bone. SYN: cornu majus ossis hyoidei [TA] .
horns of hyoid bone See greater h. of hyoid bone, lesser h. of hyoid.
iliac h. bony spur of posterior part of ilium, often found in nail-patella syndrome.
inferior h. a lower or downward prolongation of a part or structure of the body. SYN: cornu inferius [TA] .
inferior h. of falciform margin of saphenous opening [TA] the lower part of the falciform margin of the opening in the fascia lata through which the greater saphenous vein passes. SYN: cornu inferius marginis falciformis hiatus sapheni [TA] , crus inferius marginis falciformis hiatus sapheni&star.
inferior h. of lateral ventricle the part of the lateral ventricle extending downward and forward into the medial part of the temporal lobe. See lateral ventricle. SYN: cornu inferius ventriculi lateralis [TA] , cornu temporale ventriculi lateralis [TA] , temporal h. [TA] .
inferior h. of thyroid cartilage [TA] one of the pair of downward prolongations at the back of the thyroid cartilage; it articulates on each side with the cricoid cartilage. SYN: cornu inferius cartilaginis thyroideae [TA] .
lateral h. [TA] the small lateral gray column of the spinal cord as appearing in transverse section containing the interomedial cell column. SEE ALSO: gray columns, under column. SYN: cornu laterale [TA] .
lesser h. of hyoid [TA] the shorter and more medial of the two processes on either side of the hyoid. SYN: cornu minus ossis hyoidei [TA] , styloid cornu.
occipital h. [TA] SYN: posterior h..
posterior h. 1. the occipital or posterior division of the lateral ventricle of the brain, extending backward into the occipital lobe; SEE ALSO: posterior column. 2. [TA] the posterior h. or gray column of the spinal cord as appearing in cross section. The posterior h. [TA] or dorsal h. [TAalt] contains spinal laminae I-VI [TA] of Rexed. The nuclei of the posterior h. are the marginal nucleus [TA] (nucleus marginalis [TA]), gelatinous substance [TA] (substantia gelatinosa [TA]), nucleus proprius [TA], secondary visceral grey substance [TA] (substantia visceralis secundaria [TA]), internal basilar nucleus [TA] (nucleus basilar internus [TA]), medial cervical nucleus [TA] (nucleus cervicalis medialis [TA]), posterior nucleus of lateral funiculus [TA] (nucleus posterior funiculi lateralis [TA]) and the lateral cervical nucleus. SYN: cornu posterius ventriculi lateralis [TA] , cornu posterius [TA] , occipital h. [TA] , cornu of spinal cord.
pulp h. a prolongation of the pulp extending toward the cusp of a tooth.
sacral h. sacral cornu.
horns of saphenous opening inferior h. of falciform margin of saphenous opening, superior h. of falciform margin of saphenous opening.
sebaceous h. a solid outgrowth from a sebaceous cyst.
superior h. of falciform margin of saphenous opening [TA] the upper part of the falciform margin of the opening in the fascia lata through which the greater saphenous vein passes. SYN: cornu superius marginalis falciformis [TA] , Burns falciform process, Burns ligament, crus superius marginis falciformis hiatus sapheni, Hey ligament.
superior h. of thyroid cartilage [TA] one of the pair of upward prolongations from the thyroid cartilage to which the lateral hyothyroid ligament attaches. SYN: cornu superius cartilaginis thyroideae [TA] .
temporal h. [TA] SYN: inferior h. of lateral ventricle.
horns of thyroid cartilage inferior h. of thyroid cartilage, superior h. of thyroid cartilage.
uterine h., h. of uterus [TA] the portion of the uterus to which the intramural section of the uterine tube enters on either the right or left. SYN: cornu uteri [TA] .
ventral h. SYN: anterior h..
warty h. SYN: cutaneous h..

Horner
Horner

Johann F., Swiss ophthalmologist, 1831–1886. See H. syndrome, H. pupil, Bernard-H. syndrome, H.-Trantas dots, under dot.

Horner
Horner

William E., U.S. anatomist, 1793–1853. See H. muscle, H. teeth, under tooth.

horny
horny (horn′e)

Of the nature or structure of horn. SYN: keratinous (2) .

horopter
horopter (ho-rop′ter)

The sum of the points in space, the images of which for a given fixation point fall on corresponding retinal points. If the fixation point is 2 m., the h. is a straight line; if less, a curve concave to the face; if more, a convex curve. [G. horos, limit, + opter, spy, scout, fr. orao, fut. opsomai, to see]
empirical h. an experimentally determined ellipse passing through the optical centers of two eyes by which points adjacent to the point of fixation, both lying on the ellipse, are perceived to be stimulating corresponding retinal points.

horripilation
horripilation (ho-rip-i-la′shun)

Erection of the fine hairs on contraction of the arrectores pilorum. [L. horreo, to bristle, + pilus, hair]

horror
horror (hor′er)

Dread; fear. [L.]
h. autotoxicus a term introduced by Ehrlich, meaning that immunity is directed against foreign materials but not against the constituents of one's own body; exceptions to this concept are the autoallergic reactions and diseases. SYN: self-tolerance. [L., dread of self-poisoning]
h. fusionis simultaneous projection into consciousness of retinal images so different that fusion is impossible. SYN: macular evasion. [L., dread of intermingling]

horsefly
horsefly (hors′fli)

See Tabanus, Anthomyia canicularis.

horsepower
horsepower (hors′pow-er)

A unit of power, 550 foot-pounds/sec, or 745.7 W.

Horsfall
Horsfall

Frank L., Jr., U.S. physician, 1906–1971. See Tamm-H. mucoprotein, Tamm-H. protein.

Horsley
Horsley

Sir Victor A.H., English surgeon, 1857–1916. See H. bone wax.

hor. som.
hor. som.

Abbreviation for L. hora somni, before sleep, at bedtime.

Hortega
Hortega

Pio del Rio, Spanish neurohistologist in South America, 1882–1945. See H. cells, under cell, H. neuroglia stain.

Horton
Horton

Bayard T., U.S. physician, *1895. See H. arteritis, H. cephalalgia, H. headache.

hospice
hospice (hos′pis)

An institution that provides a centralized program of palliative and supportive services to dying persons and their families, in the form of physical, psychological, social, and spiritual care; such services are provided by an interdisciplinary team of professionals and volunteers who are available at home and in specialized inpatient settings. [L. hospitium, hospitality, lodging, fr. hospes, guest]

hospital
hospital (hos′pi-tal)

An institution for the treatment, care, and cure of the sick and wounded, for the study of disease, and for the training of physicians, nurses, and allied health personnel. [L. hospitalis, for a guest, fr. hospes (hospit-), a host, a guest]
base h. a h. unit located in a military or recreational encampment; usually of small size and limited facilities, for immediate care of illnesses and injuries. SYN: camp h..
camp h. SYN: base h..
closed h. a h. that restricts membership on its attending or consulting staff, sometimes to employed physicians or physicians on a selective membership list, thereby limits who may admit and treat patients.
day h. a special facility, or an arrangement within a h. setting, that enables the patient to come to the h. for treatment during the day and return home or to another facility at night. Cf.:night h..
general h. any large civilian h. that is equipped to care for medical, surgical, maternity, and psychiatric cases, and usually has a resident medical staff.
government h. a h. administered by officials of the city, county, state, or nation. SYN: public h..
group h. a private h. organized and controlled by a group of physicians and restricted to the reception and care of their own patients.
maternity h. a special h. for the care of women in childbirth.
mental h. a medical institution for the care and treatment of persons with psychiatric and psychologic disorders.
municipal h. a government h. administered by city officials.
night h. a special facility, or an arrangement within a h. setting, providing treatment and lodging at night for patients able to work in the community during the day. Cf.:day h..
open h. a h. where all physicians, not only members of the regular staff, or those on a selective membership list, are permitted to send their patients and control their treatment; extremely rare, as most hospitals limit physician access to some degree.
philanthropic h. SYN: voluntary h..
private h. 1. a h. similar to a group h. except that it is controlled by a single practitioner or by the practitioner and the associates in his or her office; 2. a h. operated for profit. SYN: proprietary h..
proprietary h. SYN: private h..
public h. SYN: government h..
special h. a h. for the medical and surgical care of patients with specific types of diseases, as of the ear, nose, and throat, eyes, or mental illness.
state h. a h. supported in part by taxpayers and administered by state government officials.
teaching h. a h. that also functions as a formal center of learning for the training of physicians, nurses, and allied health personnel.
Veterans Administration h. a h. operated at federal government expense and administered by the Veterans Administration for care of veterans of U.S. wars and retired military personnel.
voluntary h. a h. supported in part by voluntary contributions and under the control of a local, usually self-appointed, board of managers; a non-profit h.. SYN: philanthropic h..
weekend h. a special facility, or an arrangement within a h. setting, which enables a patient to work in the community during the work week and receive treatment in the h. during the weekend.

hospitalist hospitalist (hos′pit-al-ist)

1. A physician whose professional activities are performed chiefly within a hospital, e.g., anesthesiologists, emergency department physicians, intensivists (intensive care specialists), pathologists, and radiologists. SYN: hospital-based physician. 2. A primary care physician (not a house officer) who assumes responsibility for the observation and treatment of hospitalized patients and returns them to the care of their private physicians when they are discharged from the hospital. [hospital + -ist] Hospitalists may be employees of a hospital or HMO, contractors, or private practitioners. Hospital-based primary care physicians free general practitioners from the need to make daily rounds to visit hospitalized patients. While the availability of physicians oriented to inpatient care improves the efficiency of health care delivery and shortens hospital stays, some have viewed it as a threat to the integrity of the traditional patient-physician relationship. Organized medicine has opposed contractual relationships, including managed-care arrangements, whereby private physicians are required to turn over to a h. the care of all patients admitted to a hospital. While this arrangement bears many similarities to the British system of consultants and general practitioners, some have noted that limiting primary care physicians to office practice may lead to a weakening of critical diagnostic and therapeutic skills and a decline of prestige among both colleagues and the public. The impact of the h. system on medical education and on the hospital staff system, whereby practitioners and consultants maintain staff “privileges” by providing inpatient care to their own patients in compliance with regulations or by-laws, has also raised concerns.

hospitalization
hospitalization (hos′pi-tal-i-za′shun)

Confinement in a hospital as a patient for diagnostic study and treatment.

host
host

The organism in or on which a parasite lives, deriving its body substance or energy from the h.. [L. hospes, a h.]
accidental h. one that harbors an organism which usually does not infect it.
amplifier h. a h. in which infectious agents multiply rapidly to high levels, providing an important source of infection for vectors in vector-borne diseases.
dead-end h. a h. from which infectious agents are not transmitted to other susceptible hosts.
definitive h. one in which a parasite reaches the adult or sexually mature stage. SYN: final h..
final h. SYN: definitive h..
intermediate h., intermediary h. 1. one in which larval or developmental stages occur; 2. a h. through which a microorganism can pass or which contains an asexual stage of a parasite. SYN: secondary h..
paratenic h. an intermediate h. in which no development of the parasite occurs, although its presence may be required as an essential link in the completion of the parasite's life cycle; e.g., the successive fish hosts that carry the plerocercoid of Diphyllobothrium latum, the broad fish tapeworm, to larger food fish eventually eaten by humans or other final hosts. SYN: transport h..
reservoir h. the h. of an infection in which the infectious agent multiplies and/or develops, and upon which the agent is dependent for survival in nature; the h. essential for the maintenance of the infection during times when active transmission is not occurring.
secondary h. SYN: intermediate h..
transport h. SYN: paratenic h..

Hounsfield
Hounsfield

Godfrey N., British electronics engineer, *1919. Developed first practical computed tomography device, the EMI scanner; received the Nobel prize in Medicine in 1979 jointly with physicist A. M. Cormack. See H. unit, H. number.

housefly
housefly (hows′fli)

See Musca, Fannia.

house officer
house officer

A person with a medical degree employed by a hospital to provide service to patients while receiving training in a medical specialty.

Houssay
Houssay

Bernardo A., Argentinian physiologist and Nobel laureate, 1887–1971. See H. animal, H. phenomenon, H. syndrome.

Houston
Houston

John, Irish physician, 1802–1845. See H. folds, under fold, H. muscle.

Hovius
Hovius

Jacob, Dutch ophthalmologist, 1710–1786. See canal of H..

Howard
Howard

John Eager, U.S. internist and endocrinologist, 1902–1985. See H. test, Ellsworth-H. test.

Howell
Howell

William H., U.S. physiologist, 1860–1945. See H. unit, H.-Jolly bodies, under body.

Howship
Howship

John, British surgeon, 1781–1841. See H. lacunae, under lacuna.

Hoyer
Hoyer

Heinrich F., Polish anatomist and histologist, 1834–1907. See H. anastomoses, under anastomosis, H. canals, under canal, Sucquet-H. canals, under canal.

HP
HP

Abbreviation for haptoglobin.

HPL
HPL

Abbreviation for human placental lactogen.

HPLC
HPLC

Abbreviation for high-pressure liquid chromatography; high-performance liquid chromatography.

HPV
HPV

Abbreviation for human papillomavirus.

H2Q
H₂Q

Symbol for ubiquinol.

h.r.a.
h.r.a.

Abbreviation for health risk assessment.

HRCT
HRCT

Abbreviation for high-resolution computed tomography.

HRSA
HRSA

Abbreviation for Health Resources and Services Administration.

HRT
HRT

Abbreviation for hormone replacement therapy.

h.s.
h.s.

Abbreviation for L. hora somni, before sleep, at bedtime.

HSIL
HSIL

Abbreviation for high-grade squamous intraepithelial lesion.

hsp
hsp

Abbreviation for heat shock proteins, under protein.

HSV
HSV

Abbreviation for herpes simplex virus.

5-HT
5-HT

Abbreviation for 5-hydroxytryptamine.

Ht
Ht

Abbreviation for total hyperopia.

HTLV
HTLV

Abbreviation for human T-cell lymphoma/leukemia virus.

HTLV-I
HTLV-I

Abbreviation for T-cell lymphotrophic virus type I; human lymphotropic virus, type 1.

HTLV-II
HTLV-II

Abbreviation for T-cell lymphotrophic virus type II; human lymphotropic virus, type 2.

HTLV-III
HTLV-III

Old abbreviation for human T-cell lymphotropic virus type III. See human immunodeficiency virus.

hU
hU, hu

Abbreviation for dihydrouridine.

Hubrecht
Hubrecht

Ambrosius A.W., Dutch zoologist and comparative anatomist, 1853–1915. See H. protochordal knot.

Hucker-Conn stain
Hucker-Conn stain

See under stain.

Hudson
Hudson

Arthur Cyril, British ophthalmologist, 1875–1962. See H.-Stähli line.

hue
hue (hu)

One of the three qualities of color; that property by which colors of the spectrum are distinguished from each other and from grays of similar brightness; determined by the wavelength or a combination of wavelengths of light.

Hueck
Hueck

Alexander F., German anatomist, 1802–1842. See H. ligament.

Huët
Huët

G.J., Dutch physician, *1879. See Pelger-H. nuclear anomaly.

Hueter
Hueter

Karl, German surgeon, 1838–1882. See H. maneuver.

Hüfner
Hüfner

Carl Gustav von, German physician, 1840–1908. See H. equation.

Huguier
Huguier

Pierre C., French surgeon, 1804–1873. See H. canal, H. circle, H. sinus.

Huhner
Huhner

Max, U.S. urologist, 1873–1947. See H. test.

Hull
Hull

Edgar, U.S. cardiologist, *1904.

hum
hum (hum)

A low continuous murmur. [echoic]
venous h. brief or continuous noise originating from the neck veins that may be confused with cardiac murmurs, particularly with the continuous murmur of patent ductus arteriosus. SYN: bruit de diable, nun's murmur.

Human Genome Initiative
Human Genome Initiative

SYN: Human Genome Project.

Human Genome Project Human Genome Project

A comprehensive effort by molecular biologists worldwide to map the human genome, which consists of about 100,000 genes, or 3 billion nucleotide base pairs. SYN: Human Genome Initiative.Initiated by Congress in 1990, the U.S. H. is a 15-year multidisciplinary effort, jointly administered by the Department of Energy and the National Institutes of Health, to map and sequence the human genome. Similar undertakings have been launched by Great Britain, Japan, and other countries, as well as by privately funded organizations. If printed out, the entire human genome would fill 1000 large-city telephone books, each having 1000 pages. Sequencing the DNA in all 46 chromosomes is expected to take 15 years and cost $3 billion, even with the help of polymerase chain reactions, fluorescent in situ hybridization, cloning of DNA segments, and automated sequencing technology. The resulting map will be a highly idealized representation, like an illustration in an anatomy atlas, since no 2 persons, except (perhaps) identical twins, have exactly the same genetic makeup. Completion of the genomic map will broaden our understanding of human biology and facilitate the detection and treatment of genetic diseases. Projects also under way to study the genomes of bacteria, yeasts, crop plants, farm animals, and other organisms will foster advances in agriculture, environmental science, and industrial processes. About 5% of the budget of the H. has been devoted to anticipating and resolving the ethical, legal, and social issues likely to arise from this research.

human papillomavirus human papillomavirus (HPV)

an icosahedral DNA virus, 55 nm in diameter, of the genus Papillomavirus, family Papovaviridae; certain types cause cutaneous and genital warts; other types are associated with severe cervical intraepithelial neoplasia and anogenital and laryngeal carcinomas. Over 70 types have been characterized on the basis of DNA relatedness. SYN: infectious papilloma virus.H. infection is the most common sexually transmitted viral disease. The interval between exposure and clinical evidence of disease ranges from 3 weeks to 8 months. A single unprotected contact with an infected person carries a 60% risk of infection. At least 80% of cervical cancers are attributable to HPV infection, and 25% of all irregularities seen on Pap smears are believed to result from the presence of the virus, which is often otherwise asymptomatic. HPV typing in women with atypical squamous cells of undetermined significance (ASCUS) on cervical Pap smear helps to identify those in whom more intensive surveillance for premalignant change is warranted. Invasive cervical cancer is associated with types 16, 18, 31, 33, and others. Some 40% of HIV-positive women develop severe cervical dysplasia caused by HPV, which in many cases proceeds to fatal cancer with an aggressiveness not commonly seen among non–HIV-positive women. External genital warts (condylomata acuminata) are usually due to HPV type 6 or 11. Women with external genital warts are not at increased risk of cervical cancer and do not need colposcopy or other special surveillance if routine Pap smears are negative. About 20–30% of HPV infections regress spontaneously. Diagnosis of HPV infection is based on visual inspection (including colposcopy with application of acetic acid to the cervix), Pap smear, and biopsy, with detection of viral DNA in tissue. Treatment options include surgical excision, cryosurgery, laser ablation, loop electrosurgical excision, and intralesional injection of interferon. External genital warts usually respond to topical treatment of podofilox gel or to imiquimod (a cytokine-inducing agent), which can be applied by the patient. Subclinical HPV infection, detectable only by Pap smear or other laboratory methods, may prove impossible to eradicate. The virus cannot be cultured, and there is no test to confirm cure.

humectant
humectant (hu-mek′tant)

1. Moistening. 2. A substance used to obtain a moistening effect ( e.g., glycerin solution).

humectation
humectation (hu-mek-ta′shun)

1. Therapeutic application of moisture. 2. Serous infiltration of the tissues. 3. Soaking of a crude drug in water preparatory to the making of an extract. [L. humecto, pp. -mectus, to moisten, fr. humeo, to be damp]

humeral
humeral (hu′mer-al)

Relating to the humerus.

humeroradial
humeroradial (hu′mer-o-ra′de-al)

Relating to both humerus and radius; denoting especially the ratio of length of one to the other.

humeroscapular
humeroscapular (hu′mer-o-skap′u-lar)

Relating to both humerus and scapula.

humeroulnar
humeroulnar (hu′mer-o-ul′nar)

Relating to both humerus and ulna; denoting especially the ratio of length of one to the other.

humerus
humerus, gen. and pl. humeri (hu′mer-us, -i) [TA]

The bone of the arm, articulating with the scapula above and the radius and ulna below. SYN: arm bone. [L. shoulder]

humidity
humidity (hu-mid′i-te)

Moisture or dampness, as of the air. [L. humiditas, dampness]
absolute h. the mass of water vapor actually present per unit volume of gas or air.
relative h. the actual amount of water vapor present in the air or in a gas, divided by the amount necessary for saturation at the same temperature and pressure; expressed as a percentage.

humin
humin (hu′min)

An insoluble brownish or blackish residue obtained upon acid hydrolysis of glycoproteins.

Hummelsheim
Hummelsheim

Eduard K.M.J., German ophthalmologist, 1868–1952. See H. operation, H. procedure.

humor
humor, gen. humoris (hu′mer, hu-mor′is) [TA]

1. [NA] Any clear fluid or semifluid hyaline anatomic substance. 2. One of the elemental body fluids that were the basis of the physiologic and pathologic teachings of the hippocratic school: blood, yellow bile, black bile, and phlegm. SEE ALSO: humoral doctrine. [L. correctly, umor, liquid]
aqueous h. [TA] the watery fluid that fills the anterior and posterior chambers of the eye. It is secreted by the ciliary processes within the posterior chambers and passes through the the pupil into the anterior chamber where it filters through the trabecular meshwork and is reabsorbed into the venous system at the iridocorneal angle by way of the sinus venosus of the sclera; SYN: h. aquosus [TA] , intraocular fluid.
h. aquosus [TA] SYN: aqueous h..
Morgagni h. SYN: Morgagni liquor.
ocular h. one of the two humors of the eye: aqueous and vitreous.
peccant humors based on the historic humoral theory of disease, such humors or deranged fluids in the body were regarded as the direct causes of various illnesses.
vitreous h. [TA] the fluid component of the vitreous body, with which it is often erroneausly equated. SYN: h. vitreus [TA] .
h. vitreus [TA] SYN: vitreous h..

humoral
humoral (hu′mor-al)

Relating to a humor in any sense.

humoralism humoralism, humorism (hu′mor-al-izm, -mor-izm)

SYN: humoral doctrine. [L. umor, humor, moisture]

hump
hump (hump)

A rounded protuberance or bulge.
buffalo h. SYN: buffalo type.
dowager h. postmenopausal cervical kyphosis of older women due to osteoporosis and compression fractures of vertebra.
Hampton h. a juxtapleural pulmonary soft tissue density on a chest radiograph, convex toward the hilum, usually at the costophrenic angle; described as a manifestation of pulmonary infarction, due to pulmonary embolism.

humpback
humpback (hump′bak)

Nonmedical term for kyphosis or gibbus.

Humphry
Humphry

Sir George M., English surgeon, 1820–1896. See H. ligament.

humulin
humulin (hu′moo-lin)

SYN: lupulin.

humulus
humulus (hu′moo-lus)

The dried fruits (strobiles) of H. lupulus (family Moraceae), a climbing herb of central and northern Asia, Europe, and North America; an aromatic bitter, mildly sedative, and a diuretic; primarily used in the brewing industry for giving aroma and flavor to beer. SYN: hops. [Mediev. L.]

hunchback
hunchback (hunch′bak)

Nonmedical term for kyphosis or gibbus.

Hünermann
Hünermann

Carl, German physician. See Conradi-H. disease.

hunger
hunger (hun′ger)

1. A desire or need for food. 2. Any appetite, strong desire, or craving. [A.S.]
affect h. emotional h. for maternal love and feelings of protection and care implied in the mother-child relationship.
narcotic h. the physiological craving for narcotics.

Hunner
Hunner

Guy L., U.S. surgeon, 1868–1957. See H. ulcer, Fenwick-H. ulcer.

Hunt
Hunt

James Ramsay, U.S. neurologist, 1872–1937. See H. neuralgia, H. paradoxic phenomenon, H. syndrome, Ramsay H. syndrome.

Hunt
Hunt

William E., U.S. neurosurgeon, *1921. See Tolosa-H. syndrome.

Hunter
Hunter

William, Scottish anatomist and obstetrician, 1718–1783. See H. ligament, H. line, H. membrane.

Hunter
Hunter

John, Scottish surgeon, anatomist, physiologist and pathologist, 1728–1793. See H. canal, H. gubernaculum, H. operation, H.-Schreger bands, under band, H.-Schreger lines, under line.

Hunter
Hunter

Charles, Canadian physician, 1872–1955. See H. syndrome.

Hunter
Hunter

William, English pathologist, 1861–1937. See H. glossitis.

hunting
hunting (hunt′ing)

The oscillation of a controlled variable, such as the temperature of a thermostat, around its set point. See h. reaction.

Huntington
Huntington

George, U.S. physician, 1850–1916. See H. chorea, H. disease.

Hurler
Hurler

Gertrud, Austrian pediatrician, 1889–1965. See H. disease, H. syndrome, Pfaundler-H. syndrome.

Hurst
Hurst

Sir Arthur Frederick (born Hertz), English physician, 1879–1944.

Hurst
Hurst

Edward Weston, 20th century Australian physician. See H. disease.

Hürthle
Hürthle

Karl W., German histologist, 1860–1945. See H. cell, H. cell adenoma, H. cell carcinoma.

Huschke
Huschke

Emil, German anatomist, 1797–1858. See H. cartilages, under cartilage, H. foramen, H. auditory teeth, under tooth, H. valve.

Hutchinson
Hutchinson

Sir Jonathan, British surgeon, 1828–1913. See H. facies, H. freckle, H. mask, H. crescentic notch, H. patch, H. pupil, H. teeth, under tooth, H. triad, H.-Gilford disease, H.-Gilford syndrome.

Hutchison
Hutchison

Sir Robert, English pediatrician, 1871–1960. See H. syndrome.

Huxley
Huxley

Thomas H., English biologist, physiologist, and comparative anatomist, 1825–1895. See H. layer, H. membrane, H. sheath.

Huygens
Huygens

Christian, Dutch physicist, 1629–1695. See H. ocular, H. principle.

HV
HV

Abbreviation for half-value.

HVA
HVA

Abbreviation for homovanillic acid.

HVL
HVL

Abbreviation for half-value layer.

hyal- hyal-

See hyalo-.

hyalin
hyalin (hi′a-lin)

A clear, eosinophilic, homogeneous substance occurring in cellular degeneration; e.g., in arteriolar walls in arteriolar sclerosis and in glomerular tufts in diabetic glomerulosclerosis. [G. hyalos, glass]
alcoholic h. SYN: Mallory bodies, under body.

hyaline
hyaline (hi′a-lin, -len)

Relating to transparent or colorless hyphae or other fungal structures. SYN: hyaloid. [G. hyalos, glass]

hyalinization
hyalinization (hi′a-lin-i-za′shun)

The formation of hyalin.

hyalinosis
hyalinosis (hi′a-li-no′sis)

hyaline degeneration, especially that of relatively extensive degree.
h. cutis et mucosae SYN: lipoid proteinosis.
systemic h. SYN: juvenile hyalin fibromatosis.

hyalinuria
hyalinuria (hi-a-li-noo′re-a)

The excretion of hyalin or casts of hyaline material in the urine. [hyalin + G. ouron, urine]

hyalitis
hyalitis (hi-a-li′tis)

SYN: vitreitis.
suppurative h. purulent vitreous humor due to exudation from adjacent structures, as in panophthalmitis.

hyalo- hyalo-, hyal-

Glassy, hyalin; vitreous. Cf.:vitreo-. [G. hyalos, glass]

hyalobiuronic acid
hyalobiuronic acid (hi′a-lo-bi-ur-on′ik)

A disaccharide made up of d-glucuronic acid and N-acetyl-d-glucosamine in a β1,3 linkage; occurs in hyaluronic acid as the repeating unit.

hyalocyte
hyalocyte (hi′a-lo-sit)

SYN: vitreous cell. [hyalo- + G. kytos, cell]

hyalogens
hyalogens (hi-al′o-jenz)

Substances similar to mucoids that are found in many animal structures ( e.g., cartilage, vitreous humor, hydatid cysts) and yield sugars on hydrolysis.

hyalohyphomycosis
hyalohyphomycosis (hi′a-lo-hi′fo-mi-ko′sis)

A general term for infection in tissue caused by a fungus with hyaline (colorless) mycelium. If the mold can be identified, disease should be given a specific name, such as aspergillosis or fusariosis. [hyalo- + G. hyphe, web, + mykes, fungus, + -osis, condition]

hyaloid
hyaloid (hi′a-loyd)

SYN: hyaline. [hyalo- + G. eidos, resemblance]

hyalomere
hyalomere (hi′a-lo-mer)

The clear periphery of a blood platelet. [hyalo- + G. meros, part]

Hyalomma
Hyalomma (hi-a-lom′a)

An Old World genus (about 21 species) of large ixodid ticks with submarginal eyes, coalesced festoons, an ornate scutum, and a long rostrum. Adults parasitize all domestic animals and a wide variety of wild animals; larvae or nymphs may parasitize small mammals, birds, and reptiles. Species harbor a great variety of pathogens of humans and animals, and also cause considerable mechanical injury. [hyalo- + G. omma, eye]
H. anatolicum former name for H. anatolicum anatolicum.
H. anatolicum anatolicum a subspecies infesting cattle, camels and horses in Asia, the Near and Middle East, southeastern Europe, and North Africa; it is a vector of bovine tropical theileriosis, of equine babesiosis, and of human Crimean-Congo hemorrhagic fever.
H. marginatum a particularly common species of tick carried by birds migrating between Europe and Asia and Africa, and the probable vector of the virus of Crimean hemorrhagic fever.
H. variegatum species of tick that is the vector of the viral agent of lymphocytic choriomeningitis in Ethiopia.

hyalophagia
hyalophagia, hyalophagy (hi′a-lo-fa′je-a, hi-a-lof′a-je)

The eating or chewing of glass. [hyalo- + G. phago, to eat]

hyalophobia
hyalophobia (hi′a-lo-fo′be-a)

Morbid fear of glass objects. SYN: crystallophobia. [hyalo- + G. phobos, fear]

hyaloplasm
hyaloplasm, hyaloplasma (hi′a-lo-plazm, -plaz′ma)

The protoplasmic fluid substance of a cell. [hyalo- + G. plasma, thing formed]
nuclear h. SYN: karyolymph.

hyaloserositis
hyaloserositis (hi′a-lo-ser-o-si′tis)

Inflammation of a serous membrane with a fibrinous exudate that eventually becomes hyalinized, resulting in a relatively thick, dense, opaque, glistening, white or gray-white coating; when the process involves the visceral serous membranes of various organs, the grossly apparent condition is sometimes colloquially termed icing liver, sugar-coated spleen, frosted heart, and so on, depending on the site. [hyalo- + Mod. L. serosa, serous membrane, + -itis, inflammation]

hyalosis
hyalosis (hi-a-lo′sis)

Degenerative changes in the vitreous body. [hyalo- + G. -osis, condition]
asteroid h. numerous small spherical bodies (“snowball” opacities) in the corpus vitreum, visible ophthalmoscopically; an age change, usually unilateral, and not affecting vision.
punctate h. a condition marked by minute opacities in the vitreous.

hyalosome
hyalosome (hi-al′o-som)

An oval or round structure within a cell nucleus that stains faintly but otherwise resembles a nucleolus. [hyalo- + G. soma, body]

hyalurate
hyalurate (hi-a-loo′rat)

SYN: hyaluronate.

hyaluronate
hyaluronate (hi-a-loo′ron-at)

A salt or ester of hyaluronic acid. SYN: hyalurate.
h. lyase a lyase that catalyzes the cleavage of hyaluronic acids, producing a number of 3-(4-deoxy-β-d-gluc-4-enuronosyl)-N-acetyl-d-glucosamines (hyalobiuronic acid). SEE ALSO: hyaluronidase (1) , hyaluronoglucosaminidase. SYN: hyaluronic lyase.

hyaluronic acid
hyaluronic acid (hi′a-loo-ron′ik)

A mucopolysaccharide made up of alternating β1,4-linked residues of hyalobiuronic acid, forming a gelatinous material in the tissue spaces and acting as a lubricant and shock absorbant generally throughout the body; it is hydrolyzed to disaccharide or tetrasaccharide units by hyaluronidase.

hyaluronic lyase
hyaluronic lyase

SYN: hyaluronate lyase.

hyaluronidase
hyaluronidase (hi′a-loo-ron′i-das)

1. Term used loosely for hyaluronate lyase, hyaluronoglucosaminidase, and hyaluronoglucuronidase, one or more of which are present in testis, sperm, other organs, bee and snake venoms, type II pneumonococci, certain hemolytic streptococci, etc. SYN: diffusing factor, Duran-Reynals permeability factor, Duran-Reynals spreading factor, invasin, spreading factor. 2. A soluble enzyme product prepared from mammalian testes; it is used to increase the effect of local anesthetics and to permit wider infiltration of subcutaneously administered fluids, is suggested in the treatment of certain forms of arthritis to promote resolution of redundant tissue, is used to speed the resorption of traumatic or postoperative edema and hematoma, is used in combination with collagenase to dissociate organs such as liver and heart into viable cell suspensions, and in histochemistry is used on tissue secretions to verify the presence of hyaluronic acid or chondroitin sulfates.

hyaluronoglucosaminidase
hyaluronoglucosaminidase (hi-a-loo′ron-o-gloo′ko-sa-min′i-das)

An enzyme hydrolyzing β1,4 linkages in hyaluronates. SEE ALSO: hyaluronidase (1) , hyaluronate lyase.

hyaluronoglucuronidase
hyaluronoglucuronidase (hi-a-loo′ron-o-gloo-kur-on′i-das)

An enzyme hydrolyzing β1,3 linkages in hyaluronates. SEE ALSO: hyaluronidase (1) .

hybaroxia
hybaroxia (hi-ba-rok′se-a)

Oxygen therapy with pressures greater than 1 atmosphere or ambient oxygen pressure applied to the entire body in a chamber or room. [G. hyper, above, + baros, pressure, + oxys, acute]

hybenzate
hybenzate (hi-ben′zat)

USAN-approved contraction for o-(4-hydroxybenzoyl)benzoate.

hybrid
hybrid (hi′brid)

1. An individual (plant or animal) whose parents are different varieties of the same species or belong to different but closely allied species. 2. Fused tissue culture cells, as in a hybridoma. 3. A bond or valence orbital obtained by the linear combination of two or more different atomic orbitals. SYN: crossbreed (1) . [L. hybrida, offspring of a tame sow and a wild boar, fr. G. hybris, violation, wantonness]
DNA-RNA h. double-stranded polynucleic acids in which one strand is DNA and the other strand is the complementary RNA; formed during transcription and during multiplication of oncogenic RNA viruses.
SV40-adenovirus h. a virion consisting of SV40 genetic material encased in an adenovirus capsid.

hybridism
hybridism (hi′brid-izm)

The state of being hybrid.

hybridization
hybridization (hi′brid-i-za′shun)

1. The process of breeding a hybrid. 2. Crossing over between related but nonallelic genes. 3. The specific reassociation of complementary strands of polynucleic acids; e.g., the formation of a DNA-RNA hybrid. 4. The process or act of forming a macromolecular hybrid in which the subunits are obtained from different sources. SYN: crossbreeding.
cell h. fusion of two or more dissimilar cells, leading to formation of a synkaryon.
cross h. annealing of a DNA probe to an imperfectly matching DNA molecule.
DNA h. a technique used to determine the relatedness of microorganisms by the speed and efficiency of the reassociation of single-stranded DNA to form double-stranded DNA when one of the strands originates from one organism and the other strand from another organism; occurs when the base sequences are complementary or nearly so.
fluorescence in situ h. SYN: fluorescent in situ h..
fluorescent in situ h. a method used to determine the chromosomal location or expression pattern of genomic DNA or cDNA fragments. The piece of DNA to be mapped (the “probe”) is labeled with a fluorescent dye and hybridized to a chromosome preparation or to a tissue section. The probe anneals to complementary DNA or RNA sequences. Examination of the chromosomes or tissue section under a fluorescence microscope reveals the number, size, and location of the target sequences. SYN: fluorescence in situ h..
nucleic acid h. SYN: anneal (5) .
overlap h. SYN: chromosome walking.
in situ h. a technique developed in 1969 for annealing nucleic acid probes to cellular DNA for detection by autoradiography. Under proper laboratory conditions, the binding process occurs spontaneously. In situ h. constitutes a key step in DNA fingerprinting. SYN: in situ nucleic acid h..
in situ nucleic acid h. SYN: in situ h..
somatic cell h. production of a heterokaryon.

hybridoma
hybridoma (hi-brid-o′ma)

A tumor of hybrid cells used in the in vitro production of specific monoclonal antibodies; produced by fusion of an established tissue culture line of lymphocyte tumor cells ( e.g., mouse plasmacytoma cells) and specific antibody-producing cells ( e.g., splenocytes from specifically immunized mice); fusions are accomplished by use of polyethylene glycol or other methods. [G. hybris, violation, wantonness, + -oma, tumor]

hyclate
hyclate (hi′klat)

USAN-approved contraction for monohydrochloride hemiethanolate hemihydrate, HCl&chmpnt;12C₂H₅OH&chmpnt;12H₂O.

hydantoin
hydantoin (hi-dan′to-in)

2,4-Imidazolidinedione;derived from urea or from allantoin; the NH–CH₂–CO group is prototypical of α-amino acids. H. derivatives are formed by the reaction of phenylisothiocyanate and a polypeptide. SYN: glycolylurea.

hydantoinate
hydantoinate (hi-dan-to′in-at)

A salt of hydantoin.

hydatid
hydatid (hi′da-tid)

1. SYN: h. cyst. 2. A vesicular structure resembling an Echinococcus cyst. [G. hydatis, a drop of water, a hyatid]
Morgagni h. SYN: vesicular appendages of epoophoron, under appendage.
nonpedunculated h. SYN: appendix of testis.
pedunculated h. SYN: appendix of epididymidis.
sessile h. SYN: appendix of testis.
stalked h. SYN: vesicular appendages of epoophoron, under appendage.

hydatidiform
hydatidiform (hi-da-tid′i-form)

Having the form or appearance of a hydatid.

hydatidocele
hydatidocele (hi-da-tid′o-sel)

A cystic mass composed of one or more hydatids formed in the scrotum. [hydatid + G. kele, tumor]

hydatidosis
hydatidosis (hi′da-ti-do′sis)

The morbid state caused by the presence of hydatid cysts.

hydatidostomy
hydatidostomy (hi′da-ti-dos′to-me)

Surgical evacuation of a hydatid cyst. [hydatid + G. stoma, mouth]

Hydatigera taeniaeformis
Hydatigera taeniaeformis (hi-da-tij′er-a te-ni-e-for′mis)

SYN: Taenia taeniaeformis.

hydatoid
hydatoid (hi′da-toyd)

1. The aqueous humor. 2. The hyaloid membrane. 3. Relating to the aqueous humor. 4. Watery or resembling water. [G. hydor (hydat-), water, + eidos, resemblance]

hydnocarpus oil
hydnocarpus oil (hid-no-kar′pus)

SYN: chaulmoogra oil.

hydr- hydr-

See hydro-.

hydracetin
hydracetin (hi-dras′e-tin)

Pure form of acetylphenylhydrazine.

hydradenitis
hydradenitis (hi′drad-e-ni′tis)

SYN: hidradenitis.

hydradenoma
hydradenoma (hi′drad-e-no′ma)

SYN: hidradenoma.

hydragogue
hydragogue (hi′dra-gog)

Producing a discharge of watery fluid; denoting a class of cathartics that retain fluids in the intestine and aid in the removal of edematous fluids, e.g., saline cathartics. [hydr- + G. agogos, drawing forth]

hydralazine hydrochloride
hydralazine hydrochloride (hi-dral′a-zen)

A vasodilating antihypertensive agent.

hydrallostane
hydrallostane (hi-dral′o-stan)

11β,17α,21-Trihydroxy-5β-pregnane-3,20-dione;a metabolite of cortisole, reduced at the 4,5 double bond. SYN: 4,5α-dihydrocortisol.

hydramitrazine tartrate
hydramitrazine tartrate (hi-dra-mi′tra-zen)

An intestinal antispasmodic.

hydramnios
hydramnios, hydramnion (hi-dram′ne-os, -ne-on)

Presence of an excessive amount of amniotic fluid, usually over 2,000 mL. SYN: polyhydramnios. [G. hydor, water, + amnion]

hydranencephaly
hydranencephaly (hi′dran-en-sef′a-le)

Absence of cereberal hemispheres, which have been replaced by fluid-filled sacs, lined by leptomeninges. The skull and its brain cavities are normal. [hydr- + G. an- priv. + enkephalos, brain]

hydrargyria
hydrargyria, hydrargyrism (hi-drar-jir′e-a, hi-drar′jir-izm)

SYN: mercury poisoning. [L. hydrargyrum, mercury]

hydrargyrum
hydrargyrum (hi-drar′ji-rum)

SYN: mercury. [G. hydrargyros, quicksilver, fr. hydor, water, + argyros, silver]

hydrarthrodial
hydrarthrodial (hi-drar-thro′de-al)

Relating to hydrarthrosis.

hydrarthrosis
hydrarthrosis (hi-drar-thro′sis)

Effusion of a serous fluid into a joint cavity. [hydr- + G. arthron, joint]
intermittent h. a disorder characterized by a periodically recurring serous effusion into the cavity of a joint; the articulation may be the seat of a chronic arthritis or may apparently be normal in the intervals of the attacks.

hydrase
hydrase (hi′dras)

Former name for hydratase.

hydrastine
hydrastine (hi-dras′ten)

An alkaloid of hydrastis; an isoquinoline chemically related to narcotine. As the hydrochloride, was used locally in the treatment of catarrhal inflammation of the mucous membranes, and internally in the treatment of gastric inflammation, as a uterine stimulant, and to check uterine hemorrhage.

hydrastinine
hydrastinine (hi-dras′ti-nen)

A semisynthetic alkaloid prepared from hydrastine; the hydrochloride has been used in uterine hemorrhage and as an oxytocic; in large doses, it is a powerful depressant of the entire motor system (motor cortex, nerve, and muscle).

hydrastis
hydrastis (hi-dras′tis)

The dried rhizome of H. canadensis (family Ranunculaceae), a native of the eastern U.S.; formerly used in the treatment of chronic catarrhal states of the mucous membranes and in metrorrhagia. SYN: golden seal, jaundice root, yellow root. [Mod. L. fr. G. hydor (hydro-), water, + drao, to accomplish]

hydratase
hydratase (hi′dra-tas)

Trivial name applied, together with dehydratase, to certain hydro-lyases (EC 4.2.1.x) catalyzing hydration-dehydration; e.g., fumarate-malate interconversion by fumarate h..

hydrate
hydrate (hi′drat)

An aqueous solvate (in older terminology, a hydroxide); a compound crystallizing with one or more molecules of water; e.g., CuSO₄&chmpnt;5H₂O.

hydrated
hydrated (hi′drat-ed)

Combined with water, forming a hydrate. SYN: hydrous.

hydration
hydration (hi-dra′shun)

1. Chemically, the addition of water; differentiated from hydrolysis, where the union with water is accompanied by a splitting of the original molecule and the water molecule. SEE ALSO: solvation. 2. Clinically, the taking in of water; used commonly in the sense of reduced h. or dehydration. 3. The formation of a shell of water molecules around a molecular entity.
absolute h. actual water excess as measured by a difference from the normal or from a given water content.

hydrazide
hydrazide (hi′dra-zid)

An organic compound of the general formula RCO–NHNH₂; an acyl derivative of hydrazine.

hydrazine
hydrazine (hi′dra-zen)

H₂N–NH₂, an oily liquid from which phenylhydrazine and similar products are derived. It is very toxic and possibly a carcinogen.

hydrazine yellow
hydrazine yellow

SYN: tartrazine.

hydrazinolysis
hydrazinolysis (hi′dra-zi-nol′i-sis)

Cleavage of chemical bonds by hydrazine; applied in protein and nucleic acid degradations.

hydrazone
hydrazone (hi′dra-zon)

A substance derived from aldehydes and ketones by reaction with hydrazine or a hydrazine derivative to give the grouping R′R&dprime;C&dbond;N&cbond;NHR.

hydremia
hydremia (hi-dre′me-a)

A condition in which the blood volume is increased as a result of an increase in the water content of plasma, with or without a reduction in the concentration of protein; there is an excess of plasma in proportion to the cellular elements and a corresponding decrease in hematocrit. SYN: dilution anemia, polyplasmia. [hydr- + G. haima, blood]

hydrencephalocele
hydrencephalocele (hi-dren-sef′a-lo-sel)

Protrusion, through a cleft in the skull, of brain substance expanded into a sac containing fluid. SYN: encephalocystocele, hydrocephalocele, hydroencephalocele. [hydr- + G. enkephalos, brain, + kele, tumor]

hydrencephalomeningocele
hydrencephalomeningocele (hi′dren-sef′a-lo-me-ning′go-sel)

Protrusion, through a defect in the skull, of a sac containing meninges, brain substance, and cerebrospinal fluid.

hydrencephalus
hydrencephalus (hi-dren-sef′a-lus)

Rarely used term for internal hydrocephalus. [hydr- + G. enkephalos, brain]

hydriatric
hydriatric, hydriatic (hi-dre-at′rik, -at′ik)

Relating to the obsolete use of water to treat or cure disease. SYN: hydrotherapeutic. [hydr- + G. iatrikos, relating to medicine]

hydric
hydric (hi′drik)

Relating to hydrogen in chemical combination.

hydride
hydride (hi′drid)

A negatively charged hydrogen ( i.e., H:⁻) or a compound of hydrogen in which it assumes a formal negative charge, e.g., sodium borohydride (NaBH₄).

hydrindantin
hydrindantin (hi-drin-dan′tin)

The reduced form of ninhydrin. It is often used in conjunction with ninhydrin in the detection of amino or imino groups.

hydro- hydro-, hydr-

1. Water, watery. 2. Containing or combined with hydrogen. 3. A hydatid. [G. hydor, water]

hydroa
hydroa (hi-dro′a)

Any vesicular or bullous eruption. SYN: hidroa. [hydro + G. oon, egg]
h. aestivale SYN: h. vacciniforme.
h. puerorum SYN: h. vacciniforme.
h. vacciniforme a recurrent eruption of erythema evolving to umbilicated bullae, occurring on exposure to the sun and affecting chiefly male children with resolution before adult life. In severe cases, hand and face deformities and corneal opacity may develop. SYN: h. aestivale, h. puerorum.

hydroadipsia
hydroadipsia (hi′dro-a-dip′se-a)

Absence of thirst for water. [hydro- + G. a- priv. + dipsa, thirst]

hydroappendix
hydroappendix (hi′dro-a-pen′diks)

Distention of the vermiform appendix with a serous fluid.

hydrobilirubin
hydrobilirubin (hi′dro-bil-i-roo′bin)

A dark brown-red pigment that may be formed when bilirubin is reduced.

hydrobromate
hydrobromate (hi-dro-bro′mat)

A salt of hydrobromic acid.

hydrobromic acid
hydrobromic acid (hi-dro-bro′mik)

An aqueous solution of hydrogen bromide (HBr); its salts are bromides.

hydrocalycosis
hydrocalycosis (hi′dro-kal-i-ko′sis)

A usually symptomless anomaly of the renal calix that is dilated from obstruction of the infundibulum; usually discovered incidentally at pyelography or autopsy; may become infected. [hydro- + G. kalyx, cup of a flower]

hydrocarbon
hydrocarbon (hi-dro-kar′bon)

A compound containing only hydrogen and carbon.
Diels h. a phenanthrene derivative obtained by the dehydrogenation of various steroids.
saturated h. a h. that contains the greatest possible number of hydrogen atoms, so that the molecule contains neither rings nor multiple bonds.

hydrocele
hydrocele (hi′dro-sel)

A collection of serous fluid in a sacculated cavity; specifically, such a collection in the space of the tunica vaginalis testis, or in a separate pocket along the spermatic cord. [hydro- + G. kele, hernia]
cervical h. a cyst formed by secretion into a persistent duct or fissure of the neck; when it involves lymph channels, it is usually a lymphangioma. SYN: h. colli.
h. colli SYN: cervical h..
communicating h. associated with patent processus vaginalis.
congenital h. a collection of fluid in the patent processus vaginalis leading from the abdominal cavity to the investing sac of the testis.
cord h. isolated h. of spermatic cord. SYN: funicular h..
Dupuytren h. bilocular h. in which the sac fills the scrotum and also extends into the abdominal cavity beneath the peritoneum.
h. feminae accumulation of serous fluid in the labium majus or in Nuck canal. SYN: Nuck h..
filarial h. h. due to microfilaria (chiefly of Wuchereria bancrofti) in the tunica vaginalis.
funicular h. SYN: cord h..
noncommunicating h. cord or scrotal h. without communication to peritoneal cavity because processus vaginalis is not patent.
Nuck h. SYN: h. feminae.
h. spinalis SYN: spina bifida.

hydrocelectomy
hydrocelectomy (hi′dro-se-lek′to-me)

Excision of a hydrocele by drainage of its fluids and, sometimes partial excision of tunical vaginalis. [hydrocele + G. ektome, excision]

hydrocephalic
hydrocephalic (hi′dro-se-fal′ik)

Relating to or suffering from hydrocephalus.

hydrocephalocele
hydrocephalocele (hi-dro-sef′a-lo-sel)

SYN: hydrencephalocele.

hydrocephaloid
hydrocephaloid (hi-dro-sef′a-loyd)

1. Resembling hydrocephalus. 2. A condition in infants suffering from diarrhea or other debilitating disease, in which there are dehydration and general symptoms resembling those of hydrocephalus without, however, any abnormal accumulation of cerebrospinal fluid.

hydrocephalus
hydrocephalus (hi-dro-sef′a-lus)

A condition marked by an excessive accumulation of cerebrospinal fluid resulting in dilation of the cerebral ventricles and raised intracranial pressure; may also result in enlargement of the cranium and atrophy of the brain. SYN: hydrocephaly. [hydro- + G. kephale, head]
communicating h. type of h. in which there is an abnormality in cerebrospinal fluid absorption; there is no obstruction to cerebrospinal fluid flow in the ventricular system or where the cerebrospinal fluid passes into the spinal canal.
congenital h. h. due to a developmental defect of the brain. SYN: primary h..
double compartment h. independent supra- and infratentorial h. usually due to a veil occlusion of the aqueduct of Sylvius.
external h. 1. accumulation of fluid in the subarachnoid spaces of the brain; 2. accumulation of fluid in the subdural space owing to a persistent communication between the subarachnoid and subdural spaces.
h. ex vacuo h. due to loss or atrophy of brain tissue; less commonly associated with raised intracranial pressure.
internal h. h. in which the accumulation of fluid is confined to the ventricles.
noncommunicating h. SYN: obstructive h..
normal pressure h. a type of h. developing usually in older people, due to failure of cerebrospinal fluid to be absorbed by the pacchionian granulations, and characterized clinically by progressive dementia, unsteady gait, urinary incontinence, and usually, a normal spinal fluid pressure. SYN: occult h..
obstructive h. h. secondary to a block in cerebrospinal fluid flow in the ventricular system or between the ventricular system and spinal canal. SYN: noncommunicating h..
occult h. SYN: normal pressure h..
otitic h. a form of h. associated with otitis media and thrombosis of one or both sigmoid sinuses of the dura, characterized by marked increase in cerebrospinal fluid pressure.
postmeningitic h. ventricular dilation following meningitis and secondary to obstruction of cerebrospinal fluid pathways.
posttraumatic h. ventricular dilation following injury, due either to impaired circulation and/or absorption of cerebrospinal fluid or due to loss of brain substance (h. ex vacuo).
primary h. SYN: congenital h..
secondary h. an accumulation of fluid in the cranial cavity, due to meningitis or obstruction to the venous flow.
thrombotic h. increase in cerebrospinal fluid and of intracranial pressure following thrombosis of the cerebral veins or sinuses; caused by septic infection, dehydration, tuberculosis, typhoid, leukemia, and other conditions.
toxic h. thrombotic h. associated with some general infection or toxic state.

hydrocephaly
hydrocephaly (hi-dro-sef′a-le)

SYN: hydrocephalus.

hydrochloric acid
hydrochloric acid (hi-dro-klor′ik)

HCl;the acid of gastric juice. The commercial product is used as an escharotic; the gas and the concentrated solution are strong irritants. SYN: muriatic acid.
diluted h. a preparation that contains, in each 100 mL, 10 g of HCl; used internally for achlorhydria.

hydrochloride
hydrochloride (hi-dro-klor′id)

A compound formed by the addition of a hydrochloric acid molecule to a basic moiety on the substance; e.g., guanine h., glycine h..

hydrochlorothiazide
hydrochlorothiazide (hi′dro-klor-o-thi′a-zid)

A potent orally effective diuretic and antihypertensive agent related to chlorothiazide; can cause hypokalemia and hyperglycemia.

hydrocholecystis
hydrocholecystis (hi′dro-ko-le-sis′tis)

Rarely used term for an effusion of serous fluid into the gallbladder. [hydro- + G. chole, bile, + kystis, bladder]

hydrocholeresis
hydrocholeresis (hi′dro-ko-ler-e′sis, -kol-er-)

Increased output of a watery bile of low specific gravity, viscosity, and solid content. [hydro- + G. chole, bile, + hairesis, a taking]

hydrocholeretic
hydrocholeretic (hi′dro-ko-ler-et′ik)

Pertaining to hydrocholeresis.

hydrocodone
hydrocodone (hi-dro-ko′don)

A potent analgesic derivative of codeine used as an antitussive and analgesic. Often used combined with aspirin or acetaminophen. SYN: dihydrocodeinone.

hydrocolloid
hydrocolloid (hi-dro-kol′oyd)

A gelatinous colloid in unstable equilibrium with its contained water, useful in dentistry for impressions because of its dimensional stability under controlled conditions.
irreversible h. a h. whose physical state is changed by an irreversible chemical reaction when water is added to a powder and an insoluble substance is formed.
reversible h. a h. composed of a base substance whose physical state may be changed from a solid or semisolid to a liquid by the application of heat and then changed to that of an elastic gel by cooling.

hydrocolpocele
hydrocolpocele, hydrocolpos (hi-dro-kol′po-sel, -kol′pos)

Accumulation of mucus or other nonsanguineous fluid in the vagina. [hydro- + G. kolpos, bosom (vagina)]

hydrocortamate hydrochloride
hydrocortamate hydrochloride (hi-dro-kor′ta-mat)

An ester-salt of hydrocortisone, used topically in the treatment of acute and chronic dermatoses.

hydrocortisone
hydrocortisone (hi-dro-kor′ti-son)

A reduction product (at C-11) of cortisone; a steroid hormone secreted by the adrenal cortex (the active hormone secreted in the greatest quantity by the adrenals) and the most potent of the naturally occurring glucocorticoids in humans; an antiinflammatory agent. SYN: cortisol.
h. acetate an ester of h. with similar actions and uses as h.. SYN: cortisol acetate.
h. cyclopentylpropionate an ester of h..
h. cypionate the cyclopentanepropionic ester of cortisone, for oral administration.
h. hydrogen succinate a form of h. administered intravenously.
h. sodium phosphate an anti-inflammatory agent for intravenous or intramuscular administration.
h. sodium succinate a very soluble ester salt of h. (cortisol), used parenterally in the management of emergencies resulting from acute adrenal insufficiency.

hydrocotarnine
hydrocotarnine (hi′dro-ko-tar′nen)

An alkaloidal principle derived from cotarnine; it is the basic hydrolytic product of narcotine; also obtained from the mother liquors of thebaine.

hydrocyanic acid
hydrocyanic acid (hi′dro-si-an′ik)

HCN;a colorless, very toxic liquid, with the odor of bitter almonds, present in bitter almonds (amygdalin), the stones of peaches, plums and other fruits, and laurel leaves; inhalation of 300 p.p.m. causes death. SYN: hydrogen cyanide, prussic acid.

hydrocyanism
hydrocyanism (hi-dro-si′an-izm)

Poisoning with hydrocyanic acid.

hydrocyst
hydrocyst (hi′dro-sist)

A cyst with clear, watery contents. [hydro- + G. kystis, bladder]

hydrocystoma
hydrocystoma (hi′dro-sis-to′ma)

1. An eruption of deeply seated vesicles, due to retention of fluid in the sweat follicles. 2. SYN: hidrocystoma. [hydro- + G. kystis, bladder, + -oma, tumor]

hydrodipsia
hydrodipsia (hi-dro-dip′se-a)

Water thirst, a characteristic of animals that ordinarily drink water. [hydro- + G. dipsa, thirst]

hydrodipsomania
hydrodipsomania (hi′dro-dip′so-ma′ne-a)

Periodic episodes of uncontrollable thirst, occasionally found in epileptic patients. [hydro- + G. dipsa, thirst, + mania, frenzy]

hydrodiuresis
hydrodiuresis (hi′dro-di-u-re′sis)

Diuresis effected by water.

hydrodynamics
hydrodynamics (hi′dro-di-nam′iks)

The branch of physics concerned with the flow of liquids. [hydro- + G. dynamis, force]

hydroencephalocele
hydroencephalocele (hi′dro-en-sef′a-lo-sel)

SYN: hydrencephalocele.

hydrofluoric acid
hydrofluoric acid (hi-dro-flor′ik)

A solution of hydrogen fluoride gas in water; a poisonous, caustic, foaming liquid that is used to clean metals and can etch glass; extremely irritating to skin and lungs.

hydrogel
hydrogel (hi′dro-jel)

A colloid in which the particles are in the external or dispersion phase and water in the internal or dispersed phase. Cf.:hydrosol.

hydrogen
hydrogen (H) (hi′dro-jen)

1. A gaseous element, atomic no. 1, atomic wt. 1.00794. 2. The molecular form (H₂) of the element. SYN: dihydrogen. [hydro- + G. -gen, producing]
activated h. h. removed by a dehydrogenase, e.g., via a flavoprotein, from a metabolite for transference to another substance with which it combines.
arseniureted h. SYN: arsine.
h. bromide HBr;a colorless gas that has a very irritating odor and fumes in moist air; in aqueous solution, it is hydrobromic acid.
h. chloride HCl;a very soluble gas which, in solution, forms hydrochloric acid.
h. cyanide SYN: hydrocyanic acid.
h. dehydrogenase a flavoprotein catalyzing the conversion of NAD⁺ to NADH by molecular h. (H₂); i.e., H₂ + NAD⁺ → H⁺ + NADH.
h. dioxide SYN: h. peroxide.
heavy h. SYN: h.-2.
h. peroxide an unstable compound readily broken down to water and oxygen, a reaction catalyzed by various powdered metals and by the enzyme, catalase; a 3% solution is used as a mild antiseptic for skin and mucous membranes. SYN: h. dioxide, hydroperoxide.
h. phosphide SYN: phosphine.
phosphureted h. SYN: phosphine.
h. sulfide H₂S;a colorless, flammable, toxic gas with a familiar “rotten egg” odor, formed in the decomposition of organic matter containing sulfur; used as a reagent, and in the manufacture of chemicals. SYN: sulfureted h..
sulfureted h. SYN: h. sulfide.

hydrogen-1
hydrogen-1 (¹H)

The common h. isotope, making up 99.985% of the h. atoms occurring in nature. SYN: protium.

hydrogen-2
hydrogen-2 (²H)

The isotope of h. of atomic wt. 2; the less common stable isotope of h., making up 0.015% of the h. atoms occurring in nature; the nucleus consists of a proton and a neutron. SYN: deuterium, heavy hydrogen.

hydrogen-3
hydrogen-3 (³H)

A hydrogen isotope of atomic wt. 3; weakly radioactive, emitting beta particles to become the stable helium-3; half-life, 12.32 years. SYN: tritium.

hydrogenase
hydrogenase (hi′dro-je-nas, hi-droj′e-nas)

1. Any enzyme that removes a hydride ion (or H:⁻) from NADH (or NADPH). SYN: hydrogenlyase. 2. The enzyme that catalyzes the reaction of 2H⁺ with ferricytochrome or ferredoxin to generate H₂.

hydrogenation
hydrogenation (hi′dro-je-na′shun, hi-droj′e-na-shun)

Addition of hydrogen to a compound, especially to an unsaturated fat or fatty acid; thus, soft fats or oils are solidified or “hardened.”

hydrogen exponent
hydrogen exponent

The decadic logarithm of the hydrogen ion concentration in blood or other fluid; its negative is the pH of that fluid.

hydrogenlyase
hydrogenlyase (hi′dro-gen-li′as)

SYN: hydrogenase (1) .

hydrokinetic
hydrokinetic (hi′dro-ki-net′ik)

Pertaining to the motion of fluids and the forces giving rise to such motion.

hydrokinetics
hydrokinetics (hi′dro-ki-net′iks)

That branch of kinetics concerned with fluids in motion.

hydrolabile
hydrolabile (hi-dro-la′bil)

Unstable in the presence of water.

hydrolability
hydrolability (hi′dro-la-bil′i-te)

A state in which the fluid in the tissues readily changes in amount.

hydrolases
hydrolases (hi′dro-las-ez)

Enzymes (EC class 3) cleaving substrates with addition of H₂O at the point of cleavage; e.g., esterases, phosphatases, nucleases, peptidases. SYN: hydrolyzing enzymes.
cysteine h. h. that utilize an active site cysteinyl residue for the catalytic event.
serine h. h. that utilize an active site seryl residue for the catalytic event.

hydro-lyases
hydro-lyases (hi-dro-li′as-ez)

A class of lyases (EC 4.2.1.x) comprising enzymes removing H and OH as water, leading to formation of new double bonds within the affected molecule; the trivial names usually contain dehydratase or hydratase.

hydrolymph
hydrolymph (hi′dro-limf)

The circulating fluid in many of the invertebrates.

hydrolysate
hydrolysate (hi-drol′i-sat)

A solution containing the products of hydrolysis.

hydrolysis
hydrolysis (hi-drol′i-sis)

A chemical process whereby a compound is cleaved into two or more simpler compounds with the uptake of the H and OH parts of a water molecule on either side of the chemical bond cleaved; h. is effected by the action of acids, alkalies, or enzymes. Cf.:hydration. SYN: hydrolytic cleavage. [hydro- + G. lysis, dissolution]

hydrolytic
hydrolytic (hi-dro-lit′ik)

Referring to or causing hydrolysis.

hydrolyze
hydrolyze (hi′dro-liz)

To subject to hydrolysis.

hydroma
hydroma (hi-dro′ma)

SYN: hygroma.

hydromassage
hydromassage (hi′dro-ma-sahzh)

Massage produced by streams of water.

hydromeningocele
hydromeningocele (hi′dro-men-ing′go-sel)

Protrusion of the meninges of brain or spinal cord through a defect in the bony wall, the sac so formed containing cerebrospinal fluid. [hydro- + G. meninx, membrane, + kele, hernia]

hydrometer
hydrometer (hi-drom′e-ter)

An instrument for determining the specific gravity or density of a liquid. SYN: areometer, gravimeter. [hydro- + G. meron, measure]

hydrometra
hydrometra (hi-dro-me′tra)

Accumulation of thin mucus or other watery fluid in the cavity of the uterus. [hydro- + G. metra, uterus]

hydrometric
hydrometric (hi-dro-met′rik)

Relating to hydrometry or the hydrometer.

hydrometrocolpos
hydrometrocolpos (hi′dro-me-tro-kol′pos)

Distention of uterus and vagina by fluid other than blood or pus. [hydro- + G. metra, uterus, + kolpos, bosom (vagina)]

hydrometry
hydrometry (hi-drom′e-tre)

Determination of the specific gravity of a fluid by means of a hydrometer.

hydromicrocephaly
hydromicrocephaly (hi′dro-mi-kro-sef′a-le)

Microcephaly associated with an increased amount of cerebrospinal fluid.

hydromorphone hydrochloride
hydromorphone hydrochloride (hi-dro-mor′fon)

A synthetic derivative of morphine, with analgesic potency about 10 times that of morphine. SYN: dihydromorphinone hydrochloride.

hydromphalus
hydromphalus (hi-drom′fa-lus)

A cystic tumor at the umbilicus, most commonly a vitellointestinal cyst. [hydro- + G. omphalos, umbilicus]

hydromyelia
hydromyelia (hi-dro-mi-e′le-a)

An increase of fluid in the dilated central canal of the spinal cord, or in congenital cavities elsewhere in the cord substance. [hydro- + G. myelos, marrow]

hydromyelocele
hydromyelocele (hi-dro-mi′e-lo-sel)

Protrusion of a portion of cord, thinned out into a sac distended with cerebrospinal fluid, through a spina bifida. [hydro- + G. myelos, marrow, + kele, tumor, hernia]

hydronephrosis
hydronephrosis (hi′dro-ne-fro′sis)

Dilation of the pelvis and calices of one or both kidneys. This may result from obstruction to the flow of urine, vesicoureteral reflux, or it may be a primary congenital deformity without an apparent cause. SYN: pelvocaliectasis, pyeloureterectasis. [hydro- + G. nephros, kidney, + -osis, condition]

hydronephrotic
hydronephrotic (hi′dro-ne-frot′ik)

Relating to hydronephrosis.

hydronium
hydronium (hi-dro′ne-um)

See h. ion.

hydroparasalpinx
hydroparasalpinx (hi′dro-par-a-sal′pinks)

Accumulation of serous fluid in the accessory tubes of the oviduct. [hydro- + G. para, beside, + salpinx, trumpet]

hydropathic
hydropathic (hi-dro-path′ik)

Relating to hydropathy.

hydropathy
hydropathy (hi-drop′a-the)

The obsolete use of water to treat and cure disease.

hydropenia
hydropenia (hi-dro-pe′ne-a)

Reduction or deprivation of water. [hydro- + G. penia, poverty]

hydropenic
hydropenic (hi-dro-pe′nik)

Pertaining to or characterized by hydropenia.

hydropericardium
hydropericardium (hi′dro-par-i-kar′de-um)

A noninflammatory accumulation of fluid in the pericardial sac.

hydroperitoneum
hydroperitoneum, hydroperitonia (hi′dro-par-i-to-ne′um, -to′ne-a)

SYN: ascites. [hydro- + peritoneum]

hydroperoxidases
hydroperoxidases (hi′dro-per-oks′i-da-sez)

Those oxidoreductases that require H₂O₂ as hydrogen acceptors; e.g., peroxidases, catalase.

hydroperoxide
hydroperoxide (hi′dro-per-ok′sid)

SYN: hydrogen peroxide.

hydrophil
hydrophil, hydrophile (hi′dro-fil, -fil)

A substance that is hydrophilic.

hydrophilia
hydrophilia (hi-dro-fil′e-a)

A tendency of the blood and tissues to absorb fluid. [hydro- + G. philos, fond]

hydrophilic
hydrophilic (hi-dro-fil′ik)

1. Denoting the property of attracting or associating with water molecules, possessed by polar radicals or ions, as opposed to hydrophobic (2). 2. Tending to dissolve in water. 3. Polar. SYN: hydrophilous.

hydrophilous
hydrophilous (hi-drof′i-lus)

SYN: hydrophilic.

hydrophobia
hydrophobia (hi-dro-fo′be-a)

SYN: rabies. [hydro- + G. phobos, fear; from reports of inability to swallow and resultant resistance to oral fluids in human and animal rabies]

hydrophobic
hydrophobic (hi-dro-fob′ik)

1. Relating to or suffering from hydrophobia. 2. Lacking an affinity for water molecules, as opposed to hydrophilic. SYN: apolar (2) . 3. Tending not to dissolve in water. 4. Nonpolar.

hydrophthalmia
hydrophthalmia, hydrophthalmos, hydrophthalmus (hi′drof-thal′me-a, -thal′mos)

SYN: buphthalmia. [hydro- + G. ophthalmos, eye]

Hydrophyidae
Hydrophyidae (hi-dro-fi′i-de)

A family of snakes, the true sea snakes, characterized by a vertically compressed tail, giving it a paddle- or oarlike appearance; their fangs, like those of cobras, are small, grooved, and permanently erect. They are common in shallow waters along coastal margins in many regions of the Pacific basin and are important medically in western Malaysia and coastal Vietnam. There are numerous species, all venomous, but few bite humans.

hydropic
hydropic (hi-drop′ik)

Containing an excess of water or of watery fluid. SYN: dropsical.

hydropneumatosis
hydropneumatosis (hi-dro-noo-ma-to′sis)

Combined emphysema and edema; the presence of liquid and gas in tissues. [hydro- + G. pneuma, breath, spirit]

hydropneumopericardium
hydropneumopericardium (hi-dro-noo′mo-per-i-kar′de-um)

The presence of a serous effusion and of gas in the pericardial sac. SYN: pneumohydropericardium. [hydro- + G. pneuma, air, + pericardium]

hydropneumoperitoneum
hydropneumoperitoneum (hi-dro-noo′mo-par-i-to-ne′um)

The presence of gas and serous fluid in the peritoneal cavity. SYN: pneumohydroperitoneum. [hydro- + G. pneuma, air, + peritoneum]

hydropneumothorax
hydropneumothorax (hi′dro-noo-mo-thor′aks)

The presence of both gas and fluids in the pleural cavity. SYN: pneumohydrothorax, pneumoserothorax. [hydro- + G. pneuma, air, + thorax]

hydroposia
hydroposia (hi-dro-po′ze-a)

Water-drinking, a characteristic of animals that ordinarily drink water. [hydro- + G. posis, drinking]

hydrops
hydrops (hi′drops)

An excessive accumulation of clear, watery fluid in any of the tissues or cavities of the body; synonymous, according to its character and location, with ascites, anasarca, edema, etc. [G. h.]
endolymphatic h. SYN: Ménière disease.
fetal h., h. fetalis abnormal accumulation of serous fluid in the fetal tissues, as in erythroblastosis fetalis.
h. folliculi accumulation of fluid in a graafian follicle.
h. of gallbladder accumulation of clear watery fluid in the gallbladder as a result of long-standing cystic duct obstruction.
immune fetal h. fetal edema and ascites secondary to maternal/fetal blood group incompatibility.
nonimmune fetal h. fetal edema and ascites unrelated to maternal/fetal blood group incompatibilities; multiple etiologies include fetal cardiac disease, fetal viral disease, and fetal structural anomalies.
h. ovarii SYN: hydrovarium.
h. pericardii (hi′drops per-i-kar′de-i) an obsolete term for pericardial effusion.
h. tubae SYN: hydrosalpinx.
h. tubae profluens SYN: intermittent hydrosalpinx.

hydropyonephrosis
hydropyonephrosis (hi′dro-pi′o-ne-fro′sis)

Presence of purulent urine in the pelvis and calices of the kidney following obstruction of the ureter. [hydro- + G. pyon, pus, + nephrosis]

hydroquinol
hydroquinol (hi-dro-kwin′ol)

SYN: hydroquinone.

hydroquinone
hydroquinone (hi-dro-kwin′on)

An antioxidant used in ointments. SYN: hydroquinol, quinol.

hydrorchis
hydrorchis (hi-dror′kis)

A collection of fluid (hydrocele) around the testis, as in the tunica vaginalis or along the spermatic cord. [hydro- + G. orchis, testicle]

hydrorheostat
hydrorheostat (hi-dro-re′o-stat)

A rheostat in which resistance to the flow of electric current is provided by water.

hydrorrhea
hydrorrhea (hi-dro-re′a)

A profuse discharge of watery fluid from any part of the body. [hydro- + G. rhoia, flow]
h. gravidae, h. gravidarum discharge of a watery fluid from the vagina during pregnancy.

hydrosalpinx
hydrosalpinx (hi-dro-sal′pinks)

Accumulation of serous fluid in the fallopian tube, often an end result of pyosalpinx. SYN: hydrops tubae. [hydro- + G. salpinx, trumpet]
intermittent h. intermittent discharge of watery fluid from the oviduct. SYN: hydrops tubae profluens.

hydrosarca
hydrosarca (hi-dro-sar′ka)

SYN: anasarca. [hydro- + G. sarx, flesh]

hydrosarcocele
hydrosarcocele (hi-dro-sar′ko-sel)

A chronic swelling of the testis complicated with hydrocele. [hydro- + G. sarx, flesh, + kele, tumor]

hydrosol
hydrosol (hi′dro-sol)

A colloid in aqueous solution, the particles being in the dispersed or internal phase and the water in the external or dispersion phase. Cf.:hydrogel.

hydrosphygmograph
hydrosphygmograph (hi-dro-sfig′mo-graf)

A sphygmograph in which the pulse beat is transmitted to the recorder through a column of water.

hydrostat
hydrostat (hi′dro-stat)

A device for regulating water level. [hydro- + G. statikos, causing to stand]

hydrostatic
hydrostatic (hi-dro-stat′ik)

Relating to the pressure of fluids or to their properties when in equilibrium.

hydrosudopathy
hydrosudopathy (hi′dro-soo-dop′a-the)

SYN: hydrosudotherapy. [hydro- + L. sudor, sweat, + G. pathos, suffering]

hydrosudotherapy
hydrosudotherapy (hi′dro-soo′do-thar′a-pe)

Hydrotherapy combined with induced sweating, as in the Turkish bath. SYN: hydrosudopathy.

hydrosyringomyelia
hydrosyringomyelia (hi′dro-si-rin′go-mi-e′le-a)

SYN: syringomyelia. [hydro- + G. hydor, water, + syrinx, a tube, + myelos, marrow]

hydrotaxis
hydrotaxis (hi-dro-tak′sis)

The movement of cells or organisms in relation to water. [hydro- + G. taxis, arrangement]

hydrotherapeutic
hydrotherapeutic (hi′dro-thar′a-pu′tik)

SYN: hydriatric.

hydrotherapeutics
hydrotherapeutics (hi′dro-thar′a-pu′tiks)

SYN: hydrotherapy.

hydrotherapy
hydrotherapy (hi-dro-thar′a-pe)

Therapeutic use of water by external application, either for its pressure effect or as a means of applying physical energy to the tissues. SYN: hydrotherapeutics. [hydro- + G. therapeia, therapy]

hydrothermal
hydrothermal (hi-dro-ther′mal)

Relating to hot water. [hydro- + G. therme, heat]

hydrothionemia
hydrothionemia (hi′dro-thi-o-ne′me-a)

The presence of hydrogen sulfide in the circulating blood. [hydro- + G. theion, sulfur, + haima, blood]

hydrothionuria
hydrothionuria (hi′dro-thi-o-noo′re-a)

The excretion of hydrogen sulfide in the urine. [hydro- + G. theion, sulfur, + ouron, urine]

hydrothorax
hydrothorax (hi-dro-thor′aks)

SYN: pleural effusion.
chylous h. SYN: chylothorax.

hydrotomy
hydrotomy (hi-drot′o-me)

In histology, tearing apart the tissue elements by injection of water. [hydro- + G. tome, a cutting]

hydrotropism
hydrotropism (hi-dro-tro′pizm, hi-drot′ro-pizm)

The property in growing organisms of turning toward a moist surface (positive h.) or away from a moist surface (negative h.). [hydro- + G. tropos, a turning]

hydrotubation
hydrotubation (hi′dro-too-ba′shun)

Injection of a liquid medication or saline solution through the cervix into the uterine cavity and fallopian tubes for dilation and/or treatment of the tubes.

hydroureter
hydroureter (hi′dro-u-re′ter, -ur′e-ter)

SYN: ureterectasia.

hydroureteronephrosis
hydroureteronephrosis (hi-dro-u-re′ter-o-net-ro′sis)

SYN: ureterohydronephrosis.

hydrous
hydrous (hi′drus)

SYN: hydrated.

hydrovarium
hydrovarium (hi-dro-va′re-um)

A collection of fluid in the ovary. SYN: hydrops ovarii.

hydroxamic acids
hydroxamic acids (hi-drok-sam′ik)

R&cbond;CO&cbond;NH&cbond;OH ⇆ RC(OH)&dbond;N&cbond;OH;hydroxylamine derivatives of carboxylic acids, including amino acids, formed by the action of hydroxylamine.

hydroxide
hydroxide (hi-drok′sid)

1. A compound containing a potentially ionizable hydroxyl group; particularly a compound that liberates OH⁻ upon dissolving in water. 2. The h. anion, OH⁻.

hydroxocobalamin
hydroxocobalamin (hi-drok′so-ko-bal′a-min)

Vitamin B_12b, differing from cyanocobalamin (vitamin B₁₂) in the presence of a hydroxyl ion in place of the cyanide ion at the sixth coordinate position on the cobalt atom. SEE ALSO: vitamin B₁₂. SYN: hydroxocobemine.

hydroxocobemine
hydroxocobemine (hi-drok′so-ko-be-men)

SYN: hydroxocobalamin.

hydroxy- hydroxy-

Prefix indicating addition or substitution of the –OH group to or in the compound whose name follows. SEE ALSO: oxa-, oxo-, oxy-.

hydroxyacetic acid
hydroxyacetic acid (hi-drok′se-a-se′tik)

SYN: glycolic acid.

hydroxy acid
hydroxy acid (hi-drok′se)

An organic acid containing both OH and COOH groups; e.g., lactic acid.

3-hydroxyacyl-CoA dehydrogenase
3-hydroxyacyl-CoA dehydrogenase (hi-drok′se-as′il)

β-Hydroxyacyl dehydrogenase;an enzyme catalyzing the oxidation of an l-3-hydroxyacyl-CoA to a 3-ketoacyl-CoA with the concomitant reduction of NAD⁺; one of the enzymes of the β oxidation of fatty acids. SYN: β-ketohydrogenase, β-ketoreductase.

hydroxyacylglutathione hydrolase
hydroxyacylglutathione hydrolase (hi-drok′se-as′il-gloo-ta-thi′on)

An enzyme with catalytic activity similar to that of lactoylglutathione lyase, but more general; catalyzes the hydrolysis of an S-2-hydroxyacylglutathione, producing glutathione and a 2-hydroxy acid anion. SEE ALSO: glyoxalase.

3-hydroxyanthranilic acid
3-hydroxyanthranilic acid (hi-drok′se-anth-ra-nil′ik)

A metabolite of tryptophan degradation that can serve as a precursor for the biosynthesis of NAD⁺.

hydroxyapatite
hydroxyapatite (hi-drok′se-ap-a-tit)

A natural mineral structure that the crystal lattice of bones and teeth ( i.e., amorphous h.) closely resembles; used in chromatography of nucleic acids; also found in pathologic calcifications ( e.g., atherosclerotic aortas). SYN: hydroxylapatite.
amorphous h. containing ion contaminants ( e.g., 6–8% CO₃²⁻, 3–5% Mg²⁺, F⁻, Cl⁻, etc.); found in mineralized connective tissue ( e.g., bone, dentin, cementum). SYN: poorly crystalline h..
poorly crystalline h. SYN: amorphous h..

3-hydroxybutanoic acid
3-hydroxybutanoic acid

SYN: 3-hydroxybutyric acid.

4-hydroxybutyrate
4-hydroxybutyrate

SYN: γ-hydroxybutyrate.

3-hydroxybutyric acid
3-hydroxybutyric acid (hi-drok′se-bu-tir′ik)

The d-stereoisomer is one of the ketone bodies and is formed in ketogenesis; it is an important fuel for extrahepatic tissues; as an acyl derivative it is also an intermediate in fatty acid biosynthesis. The l-isomer is found as a coenzyme A derivative in β oxidation of fatty acids. SYN: 3-hydroxybutanoic acid, β-hydroxybutyric acid.
d-3-hydroxybutyric acid dehydrogenase an enzyme that reversibly catalyzes the interconversion of the two main ketone bodies, catalyzing acetoacetate + NADH + H⁺ ⇆ d-3-hydroxybutyrate + NAD⁺.

4-hydroxybutyric aciduria
4-hydroxybutyric aciduria (hi-drok′se-bu-tir′ik)

Elevated levels of 4-hydroxybutyrate in the urine. An inherited disorder that can lead to hypotonia and mental retardation.

hydroxycarbamide
hydroxycarbamide (hi-drok′se-kar′ba-mid)

SYN: hydroxyurea.

hydroxychloroquine sulfate
hydroxychloroquine sulfate (hi-drok′se-klor′o-kwin)

A quinoline derivative; an antimalarial agent whose actions and uses resemble those of chloroquine phosphate; also used in the treatment of lupus erythematosus and rheumatoid arthritis.

25-hydroxycholecalciferol
25-hydroxycholecalciferol (HCC) (hi-drok′se-ko′le-kal-sif′er-ol)

SYN: calcidiol.

hydroxychroman
hydroxychroman (hi-drok-se-kro′man)

SYN: chromanol.

hydroxychromene
hydroxychromene (hi-drok-se-kro′men)

SYN: chromenol.

hydroxyephedrine
hydroxyephedrine (hi-drok′se-e-fed′ren)

A sympathomimetic agent for the treatment of shock.

25-hydroxyergocalciferol
25-hydroxyergocalciferol (hi-drok′ser′go-kal-sif′er-ol)

A biologically active and major circulatory metabolite of vitamin D₂. SYN: ercalcidiol.

hydroxyfatty acid
hydroxyfatty acid (hi-drok′se-fat′te)

A fatty acid that has a hydroxyl group covalently attached to it ( E.G., in hydroxynervone).

3-hydroxyglutaric acid
3-hydroxyglutaric acid (hi-drok′se-gloo-tar′ik)

A dicarboxylic acid that accumulates in individuals with glutaric acidemia type I.

hydroxyhemin
hydroxyhemin (hi-drok-se-he′min)

SYN: hematin.

hydroxykynureninuria
hydroxykynureninuria (hi-drok′se-ki-noo′re-ni-noo′re-a) [MIM*236800]

An abnormality in tryptophan metabolism, probably due to a defect in kynureninase, characterized by mild mental retardation, migraine-like headaches, and urinary excretion of large amounts of kynurenine, 3-hydoxykynurenine, and xanthurenic acid; autosomal recessive inheritance.

hydroxyl
hydroxyl (hi-drok′sil)

The radical or moiety, –OH.

hydroxylamine
hydroxylamine (hi-drok′sil-a′men)

1. NH₂OH;a partially oxidized derivative of ammonia; reacts with carbonyl groups to produce oximes; forms acid salts, e.g., h. hydrochloride. It is a chemical mutagen that causes deamination of cytosine residues in DNA. 2. Any compound containing RNH&cbond;OH.
h. reductase an enzyme catalyzing the reversible reduction of h. to ammonia with a variety of donors ( e.g., methylene blue, flavin). SEE ALSO: NADH-h. reductase.

hydroxylamino
hydroxylamino (hi-drok′sil-am-i-no)

The monovalent group or moiety, &cbond;NH&cbond;OH.

hydroxylapatite
hydroxylapatite (hi-drok′sil-ap-a-tit)

SYN: hydroxyapatite.

hydroxylases
hydroxylases (hi-drok′si-la-sez)

Enzymes catalyzing formation of hydroxyl groups by addition of an oxygen atom, hence oxidizing the substrate; most are found in EC subclass 1.14.

hydroxylation
hydroxylation (hi-drok-si-la′shun)

Placing of a hydroxyl group on a compound in a position where one did not exist before.

5-hydroxylysine
5-hydroxylysine (5Hyl)

A hydroxylated amino acid found in certain collagens. The decreased ability to form h. is associated with Ehlers-Danlos syndrome type VI. SYN: δ-hydroxylysine.

3-hydroxy-3-methylglutaryl-CoA
3-hydroxy-3-methylglutaryl-CoA

SYN: β-hydroxy-β-methylglutaryl-CoA.

hydroxynervone
hydroxynervone (hi-drok-se-ner′von)

A cerebroside containing α-hydroxynervonic acid. SYN: oxynervone.

hydroxynervonic acid
hydroxynervonic acid (hi-drok′se-ner-von′ik)

An important constituent of certain cerebrosides.

hydroxyphenyluria
hydroxyphenyluria (hi-drok′se-fen-il-oo′re-a)

Urinary excretion of tyrosine and phenylalanine, as a result of ascorbic acid deficiency; occurs notably in those premature infants who lack this vitamin.

21-hydroxyprogesterone
21-hydroxyprogesterone

SYN: deoxycorticosterone.

3-hydroxyproline
3-hydroxyproline (3Hyp) (hi-drok′se-pro′len)

A derivative of proline found in certain collagens, particularly basement membrane collagen. SYN: 3-hydroxy-2-pyrrolidinecarboxylic acid.

4-hydroxyproline
4-hydroxyproline (4Hyp, Hyp)

4-Hydroxy-2-pyrrolidinecarboxylic acid;the trans-l-isomer is a pyrrolidine found among the hydrolysis products of collagen; not found in proteins other than those of connective tissue. A vitamin C deficiency will result in impaired formation of hydroxyproline.
4-hydroxyproline oxidase 1. a flavoenzyme that catalyzes the conversion of h. to Δ′-pyrroline-3-hydroxy-5-carboxylate using FAD; this enzyme appears to be deficient in individuals with hyperhydroxyprolinemia; 2. an enzyme that catalyzes the reaction of h. with NAD⁺ to form NADH and 4-oxoproline. SYN: 4-oxoproline reductase.

hydroxyprolinemia
hydroxyprolinemia (hi-drok′se-pro-li-ne′me-a) [MIM*237000]

A metabolic disorder characterized by mental retardation and microscopic hematuria in some patients; associated with enhanced plasma concentration and urinary excretion of free hydroxyproline because of a deficiency of hydroxyproline oxidase; autosomal recessive inheritance.

15-hydroxyprostaglandin dehydrogenase
15-hydroxyprostaglandin dehydrogenase (hi-drok′se-pros-ta-glan′din)

An enzyme that catalyzes the oxidation of prostaglandins, rendering them inactive, by converting the 15-hydroxyl group to a keto group using NAD⁺.

6-hydroxypurine
6-hydroxypurine

SYN: hypoxanthine.

3-hydroxy-2-pyrrolidinecarboxylic acid
3-hydroxy-2-pyrrolidinecarboxylic acid

SYN: 3-hydroxyproline.

8-hydroxyquinoline
8-hydroxyquinoline (hi-drok-se-kwin′o-lin)

A fungistat and chelating agent. SYN: quinolinol.

hydroxystilbamidine isethionate
hydroxystilbamidine isethionate (hi-drok′se-stil-bam′i-den)

An antifungal and antiprotozoan agent used in the treatment of the nonprogressive cutaneous form of blastomycosis.

hydroxytoluic acid
hydroxytoluic acid (hi-drok′se-to-loo′ik)

SYN: mandelic acid.

5-hydroxytryptamine
5-hydroxytryptamine (5-HT) (hi-drok-se-trip′ta-men)

SYN: serotonin.

hydroxytryptophan decarboxylase
hydroxytryptophan decarboxylase (hi-drok-se-trip′to-fan)

SYN: aromatic d-amino acid decarboxylase.

3-hydroxytyramine
3-hydroxytyramine (hi-drok-se-ti′ra-men)

SYN: dopamine.

hydroxyurea
hydroxyurea (hi-drok′se-u-re′a)

An oral antineoplastic agent that inhibits DNA synthesis; used in the treatment of a variety of malignancies including melanoma, chronic myelocytic leukemia, and carcinoma of the ovary. SYN: hydroxycarbamide.

hydroxyzine
hydroxyzine (hi-drok′si-zen)

A mild sedative and minor tranquilizer used in neuroses; available as the hydrochloride and pamoate. Often used to prevent nausea and to enhance the effects of narcotics.

Hydrozoa
Hydrozoa (hi-dro-zo′a)

A class of coelenterates or jellyfishes, including Hydra, a freshwater polyp, Physalia, the “Portuguese man-of-war,” Millepora, a stinging coral, and the sea wasps, Chironex heckeri and Chiropsalmus quadrigatus, whose stings can cause severe wheals, pain, and skin necrosis, and occasionally rapid death from respiratory and cardiac depression. [hydro- + G. zoon, animal]

hygieiology
hygieiology (hi-je-yol′o-je)

The science of hygiene and sanitation, and the practice thereof. [G. hygieia, health, + -logia]

hygieist
hygieist (hi′je-ist)

SYN: hygienist. [G. hygieia, health]

hygiene
hygiene (hi′jen)

1. The science of health and its maintenance. 2. Cleanliness that promotes health and well being, especially of a personal nature. [G. hygieinos, healthful, fr. hygies, healthy]
criminal h. obsolete term for the branch of mental h. or penology devoted to the study of the causes and prevention of criminality and the treatment of criminals.
industrial h. practices adopted by an industrial concern to minimize occupation-related disease and/or injury.
mental h. the science and practice of maintaining and restoring mental health; a branch of early twentieth century psychiatry that has become an interdisciplinary field including subspecialties in psychology, nursing, social work, law, and other professions.
oral h. the cleaning of the mouth by means of brushing, flossing, irrigating, massaging, or the use of other devices. SEE ALSO: oral physiotherapy.

hygienic
hygienic (hi-jen′ik, hi-je-en′ik)

Healthful; relating to hygiene; tending to maintain health.

hygienist
hygienist (hi-je′nist, hi′je-en-ist)

One who is skilled in the science of health and its maintenance. SYN: hygieist.
dental h. a licensed, professional auxiliary in dentistry who is both an oral health educator and clinician, and who uses preventive, therapeutic, and educational methods for the control of oral diseases.

hygr- hygr-

See hygro-.

hygric
hygric (hi′grik)

Relating to moisture. [G. hygros, moist]

hygric acid
hygric acid

N-Methylproline, the methylbetaine of which is stachydrine.

hygro- hygro-, hygr-

Moisture, humidity; opposite of xero-. [G. hygros, moist]

hygroma
hygroma (hi-gro′ma)

A cystic swelling containing a serous fluid, such as housemaid's knee, etc. SYN: hydroma. [hygro- + G. -oma, tumor]
h. axillare h. of the axillary region.
cervical h. a benign cystic overgrowth of lymphatics of the neck, present at birth, which may form a large tumor-like mass. SYN: h. colli cysticum.
h. colli cysticum SYN: cervical h..
cystic h. fetal malformation of fluid accumulations, usually around the neck and shoulders; may be simple or complex; often associated with Turner syndrome.
subdural h. accumulation in the subdural space of proteinaceous fluid, usually derived from serum, or of cerebrospinal fluid due to a tear in the arachnoid membrane.

hygrometer
hygrometer (hi-grom′e-ter)

Any device for measuring the water vapor in the atmosphere, usually indicating relative humidity directly. [hygro- + G. metron, measure]

hygrometry
hygrometry (hi-grom′e-tre)

SYN: psychrometry.

hygrophobia
hygrophobia (hi-gro-fo′be-a)

Morbid fear of dampness or moisture. [hygro- + G. phobos, fear]

hygroscopic
hygroscopic (hi-gro-skop′ik)

Denoting a substance capable of readily absorbing and retaining moisture; e.g., NaOH, CaCl₂.

hygrostomia
hygrostomia (hi′gro-sto′me-a)

SYN: sialorrhea. [hygro- + G. stoma, mouth]

Hyl
Hyl

Symbol for hydroxylysine or hydroxylysyl (5Hyl specifically refers to 5-hydroxylysine).

5Hyl
5Hyl

Abbreviation for 5-hydroxylysine.

hyla
hyla (hi′la)

A lateral extension of the cerebral (or sylvian) aqueduct. [G. hyle, wood]

hylephobia
hylephobia (hi-le-fo′be-a)

Morbid fear of forests. [G. hyle, forest, + phobos, fear]

hymen
hymen (hi′men) [TA]

A thin membranous fold highly variable in appearance which partly occludes the ostium of the vagina prior to its rupture (which may occur for a variety of reasons). It is frequently absent (even in virgins) although remnants are commonly present as hymenal caruncula tags. [G. h., membrane]
h. bifenestratus, h. biforis a h. in which there are two openings separated by a wide septum. Cf.:septate h..
cribriform h. a h. with a number of small perforations.
denticulate h. a h. with markedly serrated edges.
imperforate h. a h. in which there is no opening, the membrane completely occluding the vagina.
infundibuliform h. a projecting, funnel-shaped h. with a central opening with sloping edges.
h. sculptatus a h. with markedly uneven and ragged edges.
septate h. a h. in which there are two openings separated by a narrow band of tissue. Cf.:h. bifenestratus.
h. subseptus a h. in which the opening is partly closed by a septum.
vertical h. a h. in which the opening is perpendicular.

hymenal
hymenal (hi′men-al)

Relating to the hymen.

hymenectomy
hymenectomy (hi-me-nek′to-me)

Excision of the hymen. [G. hymen, membrane, + ektome, excision]

hymenitis
hymenitis (hi-me-ni′tis)

Inflammation of the hymen.

hymenoid
hymenoid (hi′men-oyd)

1. SYN: membranous. 2. Resembling the hymen.

hymenolepiasis
hymenolepiasis (hi′me-no-le-pi′a-sis)

Illness produced by infection with tapeworms of the genus Hymenolepis.

hymenolepidid
hymenolepidid (hi′men-o-lep′i-did)

Common name for tapeworms of the family Hymenolepididae.

Hymenolepididae
Hymenolepididae (hi′men-o-lep′i-did-e)

A family of tapeworms (order Cyclophyllidea) that includes the medically important genus Hymenolepis. [G. hymen, membrane, + lepis, rind]

Hymenolepis
Hymenolepis (hi-me-nol′e-pis)

The largest genus (family Hymenolepididae) of tapeworms in the order Cyclophyllidea; especially common parasites of rodents, shrews, and aquatic birds. [G. hymen, membrane, + lepis, rind]
H. diminuta a tapeworm species of rats and mice, rarely found in man; its cysticercoid larvae are harbored by beetles, fleas, caterpillars, and other insects.
H. lanceolata a tapeworm of aquatic birds, rarely found in humans.
H. nana the dwarf or dwarf mouse tapeworm; a small tapeworm of man, sometimes found in great numbers in the intestine; the cysticercoid can develop by two pathways: in the final host, with the egg from one human directly infective to another human host, in which both larval and adult stages occur, or through two hosts, an insect (or crustacean) intermediate and a vertebrate final host, the obligate two-host cycle of most cyclophylidean cestodes; in addition, H. nana can internally reinfect the same human or rodent host, producing a massive reinfection.
H. nana, fraterna a race, strain, or subspecies of H. nana adapted to mice, although infectivity to humans may remain; the human form, H. nana, presumably is derived from the rodent strain.

hymenology
hymenology (hi-me-nol′o-je)

The branch of anatomy and physiology concerned with the membranes of the body. [G. hymen, membrane, + logos, study]

Hymenoptera
Hymenoptera (hi-me-nop′ter-a)

An order of insects, including bees, wasps, and ants, characterized by locked pairs of membranous wings and high development of social or colonial behavior. [G. hymen, membrane, + pteron, wing]

hymenorrhaphy
hymenorrhaphy (hi-me-nor′a-fe)

Obsolete procedure of suturing the hymen in order to close the vagina. [G. hymen, membrane, + raphe, a suture]

hymenotomy
hymenotomy (hi-me-not′o-me)

Surgical division of a hymen. [G. hymen, membrane, + tome, incision]

Hynes
Hynes

Wilfred, British plastic surgeon, *1903.

hyo- hyo-

U-shaped, hyoid. [G. hyoeides, shaped like the letter upsilon, Υ]

hyoepiglottic
hyoepiglottic (hi′o-ep-i-glot′ik)

Relating to the hyoid bone and the epiglottis; denoting the elastic h. ligament connecting the two structures. SYN: hyoepiglottidean.

hyoepiglottidean
hyoepiglottidean (hi′o-ep-i-glo-tid′e-an)

SYN: hyoepiglottic.

hyoglossal
hyoglossal (hi′o-glos′al)

Relating to the hyoid bone and the tongue. SYN: glossohyal.

hyoglossus
hyoglossus (hi′o-glos′us)

SYN: h. (muscle).

hyoid
hyoid (hi′oyd)

U-shaped or V-shaped; denoting the h. bone and the h. apparatus. [G. hyoeides, shaped like the letter upsilon, Υ]

hyopharyngeus
hyopharyngeus (hi′o-far′in-je′us)

See middle constrictor (muscle) of pharynx.

hyoscine
hyoscine (hi′o-sen)

SYN: scopolamine.
h. hydrobromide SYN: scopolamine hydrobromide.

hyoscyamine
hyoscyamine (hi-o-si′a-men)

An alkaloid found in hyoscyamus, belladonna, duboisine, and stramonium; the levorotatory component of the racemic mixture, atropine; used as an antispasmodic, analgesic, and sedative; h. hydrobromide is used for the same purposes. SYN: daturine.
h. sulfate an antispasmodic, hypnotic, and sedative, also used in parkinsonism to relieve tremor, rigidity, and excessive salivation.

hyoscyamus
hyoscyamus (hi-o-si′a-mus)

The leaves and flowering tops of H. niger (family Solanaceae); it contains hyoscyamine and hyoscine (scopolamine); an anticholinergic and antispasmodic. SYN: henbane. [G. hyoskyamos, henbane or hog's bean, fr. hys, gen. hyos, a hog, + kyamos, a bean]

hyothyroid
hyothyroid (hi′o-thi′royd)

See thyrohyoid membrane.

Hyp
Hyp

Abbreviation for hypoxanthine; hydroxyproline (3Hyp and 4Hyp specifically refer to 3-hydroxyproline and 4-hydroxyproline, respectively).

3Hyp
3Hyp

Abbreviation for 3-hydroxyproline.

4Hyp
4Hyp

Abbreviation for 4-hydroxyproline.

hyp- hyp-

Variation of the prefix hypo-, often used before a vowel. Cf.:sub-.

hypacusia
hypacusia (hi′pa-koo′ze-a, hip′a-)

SYN: hypacusis.

hypacusis
hypacusis (hi′pa-koo′sis, hip′a-)

Hearing impairment of a conductive or sensorineural nature. SYN: hypacusia, hypoacusis. [hypo- + G. akousis, hearing]

hypalbuminemia
hypalbuminemia (hi′pal-bu-mi-ne′me-a, hip′al-)

SYN: hypoalbuminemia. [G. hypo, under, + albuminemia]

hypalgesia
hypalgesia (hi′pal-je′ze-a, hip′al-)

Decreased sensibility to pain. SYN: hypoalgesia. [G. hypo, under, + algesis, sense of pain]

hypalgesic
hypalgesic, hypalgetic (hi′pal-je′sik, hip′al-; -jet′ik)

Relating to hypalgesia; having diminished sensitiveness to pain.

hypamnion
hypamnion, hypamnios (hi-pam′ne-on, -ne-os)

SYN: oligohydramnios.

hypanakinesia
hypanakinesia, hypanakinesis (hi-pan′a-ki-ne′se-a, -kin-e′sis)

Diminution in the normal gastric or intestinal movements. [G. hypo, under, + anakinesis, a to-and-fro movement]

hyparterial
hyparterial (hi′par-ter′e-al, hip′ar-)

Below or beneath an artery. [G. hypo, beneath, + arteria, artery]

hypaxial
hypaxial (hi-pak′se-al, hip-ak′)

Below any axis, such as the spinal axis or the axis of a limb. See hypomere. [G. hypo, beneath, + axis]

hypazoturia
hypazoturia (hi′paz-o-too′re-a)

SYN: hypoazoturia.

hypencephalon
hypencephalon (hi′pen-sef′a-lon)

The midbrain, pons, and medulla. [G. hypo, under, + enkephalos, brain]

hypengyophobia
hypengyophobia (hi-pen′gi-o-fo′be-a)

Morbid fear of responsibility. [G. hypengyos, responsible, + phobos, fear]

hyper- hyper-

Excessive, above normal; opposite of hypo-. [G. hyper, above, over]

hyperabduction
hyperabduction

SYN: superabduction.

hyperacidity
hyperacidity (hi′per-a-sid′i-te)

An abnormally high degree of acidity, as of the gastric juice.

hyperactivity
hyperactivity (hi′per-ak-tiv′i-te)

1. SYN: superactivity. 2. General restlessness or excessive movement such as that characterizing children with attention deficit disorder or hyperkinesis.

hyperacusis
hyperacusis, hyperacusia (hi′per-a-koo′sis, -koo′se-a)

Abnormal hearing sensitivity. SYN: auditory hyperesthesia. [hyper- + G. akousis, a hearing]

hyperadenosis
hyperadenosis (hi′per-ad-e-no′sis)

Glandular enlargement, especially of the lymphatic glands. [hyper- + G. aden, gland, + -osis, condition]

hyperadiposis
hyperadiposis, hyperadiposity (hi′per-ad-i-po′sis, -pos′i-te)

An extreme degree of adiposis or fatness.

hyperadrenalcorticalism
hyperadrenalcorticalism (hi′per-a-dre′nal-kor′ti-kal-izm)

SYN: hypercorticoidism.

hyperadrenocorticalism
hyperadrenocorticalism (hi′per-a-dre′no-kor′ti-kal-izm)

SYN: hypercorticoidism.

hyperalaninemia
hyperalaninemia (hi′per-al′a-nen-e′me-a)

Elevated levels of alanine in the serum.

hyper-β-alaninemia
hyper-β-alaninemia (hi′per-ba′ta-al′a-nen-e′me-a)

Elevated levels of β-alanine in the serum; believed to be due to a deficiency of β-alanine:pyruvate aminotransferase; leads to impaired CNS function.

hyperaldosteronism
hyperaldosteronism (hi′per-al-dos′ter-on-izm)

SYN: aldosteronism.

hyperalgesia
hyperalgesia (hi-per-al-je′ze-a)

Extreme sensitivity to painful stimuli. [hyper- + G. algos, pain]

hyperalgesic
hyperalgesic, hyperalgetic (hi′per-al-je′sik, -jet′ik)

Relating to hyperalgesia.

hyperalimentation
hyperalimentation (hi′per-al′i-men-ta′shun)

Administration or consumption of nutrients beyond minimum normal requirements, in an attempt to replace nutritional deficiencies. SYN: superalimentation, suralimentation.
enteral h. h. by the administration of elemental nutrients via a catheter placed within the intestinal tract; usually used in patients with at least a portion of functional small intestine.
parenteral h. h. of nutrients via central venous catheter in patients who cannot consume adequate nutrition by the enteral route.

hyperallantoinuria
hyperallantoinuria (hi′per-a-lan′to-i-noo′re-a)

Increased excretion of allantoin in the urine.

hyperalphalipoproteinemia
hyperalphalipoproteinemia (hi′per-al′fa-lip-o-pro′ten-e′me-a)

An inherited defect that results in elevated levels of high-density lipoproteins in the serum.

hyperaminoaciduria
hyperaminoaciduria (hi′per-am′i-no-as-i-doo′re-a)

SYN: aminoaciduria.

hyper-β-aminoisobutyric aciduria
hyper-β-aminoisobutyric aciduria

Elevated levels of β-aminoisobutyric acid in the urine; believed to be due to a deficiency of liver β-aminoisobutyrate:pyruvate aminotransferase.

hyperammonemia
hyperammonemia (hi′per-am-o-ne′me-a)

SYN: ammonemia.

hyperamylasemia
hyperamylasemia (hi′per-am′i-la-se′me-a)

Elevated serum amylase, usually seen as one of the manifestations of acute pancreatitis. [hyper- + amylase, + G. haima, blood]

hyperanacinesia
hyperanacinesia, hyperanacinesis (hi′per-an-a-si-ne′ze-a, -ne′sis)

SYN: hyperanakinesia.

hyperanakinesia
hyperanakinesia, hyperanakinesis (hi′per-an-a-ki-ne′ze-a, -ki-ne′sis)

Excessive to-and-fro movement, e.g., of the stomach or intestine. SYN: hyperanacinesia, hyperanacinesis. [hyper- + G. anakinesis, to-and-fro movement]

hyperaphia
hyperaphia (hi′per-a′fe-a)

Extreme sensitivity to touch. SYN: oxyaphia, tactile hyperesthesia. [hyper- + G. haphe, touch]

hyperaphic
hyperaphic (hi-per-af′ik)

Marked by hyperaphia.

hyperargininemia
hyperargininemia (hi′per-ar-jen-in-e-me-a)

Elevated levels of arginine in the blood plasma; usually associated with a deficiency of arginase.

hyperbaric
hyperbaric (hi-per-bar′ik)

1. Pertaining to pressure of ambient gases greater than 1 atmosphere. 2. Concerning solutions, more dense than the diluent or medium; e.g., in spinal anesthesia, a h. solution has a density greater than that of spinal fluid. [hyper- + G. baros, weight]

hyperbarism
hyperbarism (hi-per-bar′izm)

Disturbances in the body resulting from the pressure of ambient gases at greater than 1 atmosphere; e.g., nitrogen narcosis, oxygen toxicity, bends. [hyper- + G. baros, weight]

hyperbetalipoproteinemia
hyperbetalipoproteinemia (hi′per-bet-a-lip′o-pro-te-ne′me-a)

Enhanced concentration of β-lipoproteins in the blood.
familial h. See type II familial hyperlipoproteinemia.
familial h. and hyperprebetalipoproteinemia SYN: type III familial hyperlipoproteinemia.

hyperbilirubinemia
hyperbilirubinemia (hi′per-bil′i-roo-bi-ne′me-a)

An abnormally large amount of bilirubin in the circulating blood, resulting in clinically apparent icterus or jaundice when the concentration is sufficient.
neonatal h. serum bilirubin greater than 12.9 mg/dl (220 μol/L) or rising at a rate greater than 5 mg/dl per day; also applied to a nonphysiologic pattern of h., i.e., jaundice in the first 24 hours of life or extending beyond the first week of life in term infants.

hyperbrachycephaly
hyperbrachycephaly (hi′per-brak-e-sef′a-le)

An extreme degree of brachycephaly, with a cephalic index of over 85. [hyper- + G. brachys, short, + kephale, head]

hypercalcemia
hypercalcemia (hi′per-kal-se′me-a)

An abnormally high concentration of calcium compounds in the circulating blood; commonly used to indicate an elevated concentration of calcium ions in the blood.
humoral h. of benignancy h. induced by parathyroid hormonelike protein of benign tumor.
idiopathic h. of infants persistent h. of unknown cause in very young children, associated with osteosclerosis, renal insufficiency, and sometimes hypertension; also may be associated with supravalvular aortic stenosis, elfin facies, and mental retardation.

hypercalcinuria
hypercalcinuria (hi′per-kal-si-noo′re-a)

SYN: hypercalciuria.

hypercalciuria
hypercalciuria (hi′per-kal-se-yu′re-a)

Excretion of abnormally large amounts of calcium in the urine, as in hyperparathyroidism and types of hereditary hypophosphatemic rickets. SYN: calcinuric diabetes, hypercalcinuria, hypercalcuria.

hypercalcuria
hypercalcuria (hi′per-kal-ku′re-a)

SYN: hypercalciuria.

hypercapnia
hypercapnia (hi-per-kap′ne-a)

Abnormally increased arterial carbon dioxide tension. SYN: hypercarbia. [hyper- + G. kapnos, smoke, vapor]

hypercarbia
hypercarbia (hi-per-kar′be-a)

SYN: hypercapnia.

hypercardia
hypercardia (hi-per-kar′de-a)

Hypertrophy of the heart. [hyper- + G. kardia, heart]

hypercatabolic
hypercatabolic (hi′per-kat-a-bol′ik)

Pertaining to hypercatabolism.

hypercatabolism
hypercatabolism (hi′per-ka-tab′o-lizm)

Excessive metabolic breakdown of a specific substance or of body tissue in general, leading to weight loss and wasting.

hypercatharsis
hypercatharsis (hi′per-ka-thar′sis)

Excessive and frequent defecation. [hyper- + G. katharsis, a cleansing]

hypercathexis
hypercathexis (hi′per-ka-thek′sis)

In psychoanalysis, an individual's excessive investment of libido or interest in an object, person, or idea. [hyper- + G. kathexis, a holding in, retention]

hypercementosis
hypercementosis (hi′per-se-men-to′sis)

Excessive deposition of secondary cementum on the root of a tooth, which may be caused by localized trauma or inflammation, excessive tooth eruption, or osteitis deformans, or may occur idiopathically. SYN: cementum hyperplasia. [hyper- + L. caementum, a rough quarry stone, + -osis, condition]

hyperchloremia
hyperchloremia (hi′per-klo-re′me-a)

An abnormally large amount of chloride ions in the circulating blood. SYN: chloremia (2) .

hyperchlorhydria
hyperchlorhydria (hi′per-klor-hi′dre-a)

Presence of an excessive amount of hydrochloric acid in the stomach. SYN: chlorhydria, hyperhydrochloria. [hyper- + chlorhydric (acid)]

hyperchloruria
hyperchloruria (hi′per-klor-u′re-a)

Increased excretion of chloride ions in the urine.

hypercholesteremia
hypercholesteremia (hi′per-ko-les′ter-e′me-a)

SYN: hypercholesterolemia.

hypercholesterinemia
hypercholesterinemia (hi′per-ko-les′ter-i-ne′me-a)

SYN: hypercholesterolemia.

hypercholesterolemia
hypercholesterolemia (hi′per-ko-les′ter-ol-e′me-a)

The presence of an abnormally large amount of cholesterol in the blood. SYN: hypercholesteremia, hypercholesterinemia.
familial h. See type II familial hyperlipoproteinemia.
familial h. with hyperlipemia SYN: type III familial hyperlipoproteinemia.

hypercholesterolia
hypercholesterolia (hi′per-ko-les′ter-o′le-a)

The presence of an abnormally large quantity of cholesterol in the bile.

hypercholia
hypercholia (hi-per-ko′le-a)

A condition in which an abnormally large amount of bile is formed in the liver. [hyper- + G. chole, bile]

hyperchromaffinism
hyperchromaffinism (hi′per-kro′maf-in-izm)

Presence of a functioning pheochromocytoma.

hyperchromasia
hyperchromasia (hi′per-kro-ma′ze-a)

SYN: hyperchromatism.

hyperchromatic
hyperchromatic (hi′per-kro-mat′ik)

1. Abnormally highly colored, excessively stained, or overpigmented. SYN: hyperchromic (1) . 2. Showing increased chromatin. [hyper- + G. chroma, color]

hyperchromatism
hyperchromatism (hi′per-kro′ma-tizm)

1. Excessive pigmentation. 2. Increased staining capacity, especially of cell nuclei for hematoxylin. 3. An increase in chromatin in cell nuclei. SYN: hyperchromasia, hyperchromia. [hyper- + G. chroma, color]

hyperchromia
hyperchromia (hi-per-kro′me-a)

SYN: hyperchromatism.
macrocytic h. hyperchromatic macrocythemia; a misnomer inasmuch as the red blood cells are larger than normal, the total amount of hemoglobin per cell is increased, but the percentage of hemoglobin per cell is usually in the normochromic range.

hyperchromic
hyperchromic (hi-per-krom′ik)

1. SYN: hyperchromatic (1) . 2. Denoting increased light absorption. 3. Denoting more highly colored than normal. 4. Describing erythrocytes that contain, or appear to contain, more hemoglobin than normal.

hyperchylia
hyperchylia (hi-per-ki′le-a)

Excessive secretion of gastric juice. [hyper- + G. chylos, juice]

hyperchylomicronemia
hyperchylomicronemia (hi′per-ki′lo-mi-kro-ne′me-a)

Increased plasma concentrations of chylomicrons.
familial h. SYN: type I familial hyperlipoproteinemia.
familial h. with hyperprebetalipoproteinemia SYN: type V familial hyperlipoproteinemia.

hypercinesis
hypercinesis, hypercinesia (hi′per-si-ne′sis, -si-ne′ze-a)

SYN: hyperkinesis.

hypercoagulability
hypercoagulability (hi′per-ko-ag′oo-la-bil-i-te)

Abnormally increased coagulability.

hypercoagulable
hypercoagulable (hi′-per-ko-ag′oo-la-bl)

Characterized by abnormally increased coagulation.

hypercorticoidism
hypercorticoidism (hi′per-kor′ti-koyd-izm)

Excessive secretion of one or more steroid hormones of the adrenal cortex; sometimes used also to designate the state produced by therapeutic administration of large quantities of steroids having glucocorticoid activity, e.g., hydrocortisone. SEE ALSO: Cushing syndrome. SYN: adrenalism, hyperadrenalcorticalism, hyperadrenocorticalism.

hypercortisolism
hypercortisolism (hi′per-kor′ti-sol-izm)

See hyperadrenocorticalism.

hypercryalgesia
hypercryalgesia (hi′per-kri-al-je′ze-a)

SYN: hypercryesthesia. [hyper- + G. kryos, cold, + algesis, the sense of pain]

hypercryesthesia
hypercryesthesia (hi′per-kri-es-the′ze-a)

Extreme sensibility to cold. SYN: hypercryalgesia. [hyper- + G. kryos, cold, + aisthesis, sensation]

hypercupremia
hypercupremia (hi′per-koo-pre′me-a)

An abnormally high level of plasma copper. [hyper- + L. cuprum, copper, + G. haima, blood]

hypercyanotic
hypercyanotic (hi′per-si-a-not′ik)

Marked by extreme cyanosis.

hypercyesis
hypercyesis, hypercyesia (hi′per-si-e′sis, -e′ze-a)

SYN: superfetation. [hyper- + G. kyesis, pregnancy]

hypercythemia
hypercythemia (hi′per-si-the′me-a)

The presence of an abnormally high number of red blood cells in the circulating blood. SYN: hypererythrocythemia. [hyper- + G. kytos, cell, + haima, blood]

hypercytochromia
hypercytochromia (hi′per-si-to-kro′me-a)

Increased intensity of staining of a cell, especially blood cells. [hyper- + G. kytos, cell, + chroma, color]

hypercytosis
hypercytosis (hi′per-si-to′sis)

Obsolete term for any condition in which there is an abnormal increase in the number of cells in the circulating blood or the tissues; frequently used synonymously with leukocytosis.

hyperdicrotic
hyperdicrotic (hi′per-di-krot′ik)

Pronouncedly dicrotic. SYN: superdicrotic.

hyperdicrotism
hyperdicrotism (hi-per-dik′ro-tizm, -di′kro-tizm)

Extreme dicrotism.

hyperdiploid
hyperdiploid (hi′per-dip′loid)

Having a chromosome number greater than the diploid number.

hyperdipsia
hyperdipsia (hi-per-dip′se-a)

Intense thirst that is relatively temporary. [hyper- + G. dipsa, thirst]

hyperdistention
hyperdistention (hi′per-dis-ten′shun)

Extreme distention. SYN: superdistention.

hyperechoic
hyperechoic (hi′per-e-ko′ik)

1. In ultrasonography, pertaining to material that produces echoes of higher amplitude or density than the surrounding medium. 2. Denoting a region in an ultrasound image in which the echoes are stronger than normal or than surrounding structures.

hyperekplexia
hyperekplexia (hi′per-ek-pleks′e-a) [MIM#149400]

A hereditary disorder in which there are pathologic startle responses, i.e., protective reactions to unanticipated, potentially threatening, stimuli of any type, particularly auditory; the stimuli induce often widespread and violent sudden contractions of the head, neck, spinal, and sometimes limb musculature, resulting in involuntary shouting, jerking, jumping, and falling; autosomal dominant and recessive inheritance forms, with the responsible gene localized to chromosome 5q; probably the result of lack of inhibitory neurotransmitters, glycine, or GABA. SYN: kok disease, startle disease. [hyper- + G. ekplexia, sudden shock, fr. ekplesso, to startle]

hyperemesis
hyperemesis (hi-per-em′e-sis)

Excessive vomiting. [hyper- + G. emesis, vomiting]
h. gravidarum pernicious vomiting in pregnancy.
h. lactentium vomiting by nursing infants with pyloric stenosis.

hyperemetic
hyperemetic (hi′per-e-met′ik)

Marked by excessive vomiting.

hyperemia
hyperemia (hi-per-e′me-a)

The presence of an increased amount of bloodflow in a part or organ. SEE ALSO: congestion. [hyper- + G. haima, blood]
active h. h. due to an increased afflux of arterial blood into dilated capillaries. SYN: arterial h., fluxionary h..
arterial h. SYN: active h..
Bier h. obsolete term for h. produced by Bier method (2) .
collateral h. increased blood flow through abundant collateral channels when the circulation through the main artery to a part is arrested.
fluxionary h. SYN: active h..
passive h. h. due to an obstruction in the flow of blood from the affected part, the venous radicles becoming distended. SYN: venous h..
peristatic h. SYN: peristasis.
reactive h. h. following the arrest and subsequent restoration of the blood supply to a part.
venous h. SYN: passive h..

hyperemic
hyperemic (hi-per-e′mik)

Denoting hyperemia.

hyperencephaly
hyperencephaly (hi′per-en-sef′a-le)

A fetal developmental deficiency of the vault of the cranium, exposing the poorly formed brain. [hyper- + G. enkephalos, brain]

hypereosinophilia
hypereosinophilia (hi′per-e-o-sin-o-fil′e-a)

A greater degree of abnormal increase in the number of eosinophilic granulocytes in the circulating blood or the tissues; e.g., in diseases where the degree of eosinophilia usually ranges from 10–30%, an increase to 50 or 60% (or more) might be regarded as h..

hyperergia
hyperergia (hi′per-er′je-a)

An allergic hypersensitivity. SYN: hypergia.

hyperergic
hyperergic (hi-per-er′jik)

Relating to hyperergia. SYN: hypergic.

hypererythrocythemia
hypererythrocythemia (hi′per-e-rith′ro-si-the′me-a)

SYN: hypercythemia.

hyperesophoria
hyperesophoria (hi′per-es-o-fo′re-a)

A tendency of one eye to deviate upward and inward, prevented by binocular vision. [hyper- + G. eso, inward, + phora, movement]

hyperesthesia
hyperesthesia (hi′per-es-the′ze-a)

Abnormal acuteness of sensitivity to touch, pain, or other sensory stimuli. [hyper- + G. aisthesis, sensation]
auditory h. SYN: hyperacusis.
cervical h. the hypersensitivity of teeth in the cervical area due to exposure of the dentin.
gustatory h. SYN: hypergeusia.
muscular h. sensitiveness of the muscles to pressure.
olfactory h., h. olfactoria SYN: hyperosmia.
h. optica extreme sensitivity of the eyes to light. See photophobia, photosensitivity.
tactile h. SYN: hyperaphia.

hyperesthetic
hyperesthetic (hi′per-es-thet′ik)

Marked by hyperesthesia.

hypereuryprosopic
hypereuryprosopic (hi′per-u′ri-pro-sop′ik)

Pertaining to or characterized by a very low and wide face. [hyper- + G. eurys, wide, + prosopon, face]

hyperexophoria
hyperexophoria (hi′per-ek-so-fo′re-a)

A tendency of one eye to deviate upward and outward, prevented by binocular vision. [hyper- + G. exo, outward, + phora, movement]

hyperextension
hyperextension (hi′per-eks-ten′shun)

Extension of a limb or part beyond the normal limit. SYN: overextension, superextension.

hyperferremia
hyperferremia (hi′per-fer-e′me-a)

High serum iron level; found in hemochromatosis.

hyperfibrinogenemia
hyperfibrinogenemia (hi′per-fi-brin′o-je-ne′e-a)

An increased level of fibrinogen in the blood. SYN: fibrinogenemia.

hyperfibrinolysis
hyperfibrinolysis (hi′per-fi-brin-ol′i-sis)

Markedly increased fibrinolysis, as in subdural hematomas.

hyperflexion
hyperflexion (hi-per-flek′shun)

Flexion of a limb or part beyond the normal limit. SYN: superflexion.

hyperfructosemia
hyperfructosemia (hi′per-fruk-to-se-me-a)

Elevated serum fructose levels.

hypergalactosis
hypergalactosis (hi′per-ga-lak-to′sis)

Excessive secretion of milk. [hyper- + G. gala, milk, + -osis, condition]

hypergammaglobulinemia
hypergammaglobulinemia (hi′per-gam-a-glob′u-li-ne′me-a)

An increased amount of the γ-globulins in the plasma, such as that frequently observed in chronic infectious diseases.

hyperganglionosis
hyperganglionosis (hi-per-ga′ng-gle-o-no′sis)

SYN: neuronal hyperplasia.

hypergenesis
hypergenesis (hi-per-jen′e-sis)

Excessive development or redundant production of parts or organs of the body. [hyper- + G. genesis, production]

hypergenetic
hypergenetic (hi-per-je-net′ik)

Relating to hypergenesis.

hypergenitalism
hypergenitalism (hi-per-jen′i-tal-izm)

Abnormal overdevelopment of genitalia.

hypergeusia
hypergeusia (hi-per-goo′se-a, -joo′se-a)

Abnormal acuteness of the sense of taste. SYN: gustatory hyperesthesia. [hyper- + G. geusis, taste]

hypergia
hypergia (hi-per′je-a)

SYN: hyperergia.

hypergic
hypergic (hi-per′jik)

SYN: hyperergic.

hyperglandular
hyperglandular (hi-per-glan′dyu-lar)

Characterized by overactivity or increased size of a gland.

hyperglobulia
hyperglobulia, hyperglobulism (hi′per-glob-u′le-a, -glob′u-lizm)

Old term for polycythemia. [hyper- + L. globulus, globule]

hyperglobulinemia
hyperglobulinemia (hi′per-glob′u-lin-e′me-a)

An abnormally high concentration of globulins in the circulating blood plasma.

hyperglycemia
hyperglycemia (hi′per-gli-se′me-a)

An abnormally high concentration of glucose in the circulating blood, seen especially in patients with diabetes mellitus. SYN: hyperglycosemia. [hyper- + G. glykys, sweet, + haima, blood]
ketotic h. an inborn error of glycine metabolism characterized by lethargy, vomiting, convulsions, hypertonia, and difficulty breathing; milk protein and casein induce attacks; autosomal recessive inheritance.
nonketotic h. SYN: hyperosmolar (hyperglycemic) nonketotic coma.
posthypoglycemic h. SYN: Somogyi phenomenon.

hyperglyceridemia
hyperglyceridemia (hi′per-glis′er-i-de′me-a)

Elevated plasma concentration of glycerides.
endogenous h. type IV familial hyperlipoproteinemia or, more commonly, a nonfamilial sporadic variety.
exogenous h. persistent h. due to retarded rate of removal from plasma of chylomicrons of dietary origin; occurs in alcoholism, hypothyroidism, insulinopenic diabetes mellitus, types I and V hyperlipoproteinemia, and during acute pancreatitis.

hyperglycinemia
hyperglycinemia (hi′per-gli-si-ne′me-a)

Elevated plasma glycine concentration.
ketotic h. an inherited metabolic defect which results from a deficiency of propionyl Coenzyme A carboxylase, the enzyme that converts propionate to methylmalonate; the enzyme requires biotin as a cofactor; clinically, affected infants have overwhelming illness, with lethargy, metabolic acidosis with ketosis, hypotonia; coma and seizures typically develop with early death; propionic acid is markedly elevated in plasma and urine; there is also hyperammonemia, and elevated levels of other metabolites as well, including glycine, hence the original name for the syndrome. SYN: methylmalonic acidemia, propionic acidemia.
nonketotic h. [MIM*238300] an inborn error of glycine metabolism, due to a deficiency of glycine dicarboxylase P protein (GCSP), a component of glycine cleavage system; characteristically overwhelming disease in the newborn period, with coma, seizures and death, or, less often, gradual onset with failure to thrive, focal seizures, and mental retardation; there is massive elevation of plasma glycine, with increased levels in cerebrospinal fluid and urine; plasma hyperosmolality, severe dehydration occur without ketoacidosis; autosomal recessive inheritance; caused by mutation in the GCSP gene on chromosome 9p.

hyperglycinuria
hyperglycinuria (hi′per-gli-si-noo′re-a)

Enhanced urinary excretion of glycine.

hyperglycogenolysis
hyperglycogenolysis (hi′per-gli′ko-je-nol′i-sis)

Excessive glycogenolysis. [hyper- + glycogen + G. lysis, loosening]

hyperglycorrhachia
hyperglycorrhachia (hi′per-gli-ko-rak′e-a)

Excessive sugar in the cerebrospinal fluid. [hyper- + G. glykys, sweet, + rhachis, spine]

hyperglycosemia
hyperglycosemia (hi′per-gli-ko-se′me-a)

SYN: hyperglycemia.

hyperglycosuria
hyperglycosuria (hi′per-gli-ko-soo′re-a)

Persistent excretion of unusually large amounts of glucose in the urine; i.e., an extreme degree of glucosuria.

hyperglyoxylemia
hyperglyoxylemia (hi′per-gli-ok′si-le′me-a)

Enhanced plasma (and possibly tissue) concentrations of glyoxylate; may develop during thiamine deficiency.

hypergnosis
hypergnosis (hi-per-no′sis)

1. Projection of inner conflicts into the environment. 2. Exaggerated perception, such as the expansion of an isolated thought. [hyper- + G. gnosis, knowledge]

hypergonadism
hypergonadism (hi-per-go′nad-izm)

A clinical state resulting from enhanced secretion of gonadal hormones.

hypergonadotropic
hypergonadotropic (hi′per-go′na-do-trop′ik)

Indicating an increased production or excretion of gonadotropic hormones.

hypergranulosis
hypergranulosis (hi′per-gran-u-lo′sis)

Increased thickness of the granular layer of the epidermis, associated with hyperkeratosis. [hyper- + (stratum) granulosum + -osis, condition]

hyperguanidinemia
hyperguanidinemia (hi′per-gwan′i-di-ne′me-a)

A condition in which there is an abnormally large amount of guanidine in the circulating blood.

hypergynecosmia
hypergynecosmia (hi′per-gi-ne-koz′me-a)

Overdevelopment of secondary sex characteristics of the mature female or their precocious development in the young girl. [hyper- + G. gyne, woman, + kosmeo, to decorate]

hyperhedonia
hyperhedonia, hyperhedonism (hi′per-he-do′ne-a, -he′don-izm)

The feeling of an abnormally great pleasure in any act or from any happening. [hyper- + G. hedone, pleasure]

hyperhemoglobinemia
hyperhemoglobinemia (hi′per-he′mo-glo-bi-ne′mme-a)

An unusually large amount of hemoglobin in the circulating blood plasma; i.e., much more than that ordinarily observed in most examples of hemoglobinemia.

hyperheparinemia
hyperheparinemia (hi′per-hep′ar-in-e′me-a) [MIM*144050]

Elevated plasma concentrations of heparin; believed to be the cause of a heritable bleeding tendency; probably autosomal dominant inheritance.

hyperhidrosis
hyperhidrosis (hi′per-hi-dro′sis)

Excessive or profuse sweating. SYN: polyhidrosis, sudorrhea. [hyper- + hidrosis]
gustatory h. excessive sweating of the lips, nose, and forehead after eating certain foods; it is physiologic in many persons, but sometimes occurs after parotid surgery or as a result of damage to the parasympathetic or sympathetic nerves of the head and neck.

hyperhydration
hyperhydration (hi′per-hi-dra′shun)

Excess water content of the body; may result from the intravenous administration of unduly large amounts of glucose solution. SYN: overhydration.

hyperhydrochloria
hyperhydrochloria (hi′per-hi-dro-klor′e-a)

SYN: hyperchlorhydria.

hyperhydrochloridia
hyperhydrochloridia (hi′-per-hi′dro-chlor-id-e-a)

Excessive acid secretion by the stomach; associated with peptic ulcer disease. [hyper + hydrochloric, acid + -ia]

hyperhydropexy
hyperhydropexy, hyperhydropexis (hi-per-hi′dro-pek-se, hi′per-hi-dro-pek′sis)

Increased fixation of water in tissues. [hyper- + G. hydor, water, + pegnymi, to fasten]

hyperhydroxyprolinemia
hyperhydroxyprolinemia (hi′per-hi-drok′se-pro-len-e-me-a)

See hydroxyprolinemia.

hyperimidodipeptiduria
hyperimidodipeptiduria (hi′per-im′i-do-di-pep′tid-oor-e-a)

Elevated levels of imidodipeptides ( e.g., Xaa&cbond;Pro) in the urine; due to a deficiency of prolidase.

hyperimmune
hyperimmune (hi′per-im-mum′)

Having large quantities of specific antibodies in the serum from repeated immunizations or infections.

hyperimmunity
hyperimmunity (hi′per-i-mu′-ni-te)

A high degree of immunity.

hyperimmunization
hyperimmunization (hi′per-im-oo-ni-zashun)

1. The induction of a heightened state of immunity by the administration of repeated doses of antigen, often used in allergy desensitization. 2. Passively acquired immunity by the injection of hyperimmune gamma globulin.

hyperindicanemia
hyperindicanemia (hi′per-in′di-kan-e′me-a)

An unusually large amount of indican in the circulating blood; i.e., greater than that observed in most instances of indicanemia.

hyperinfection
hyperinfection (hi′per-in-fek′shun)

Infection by very large numbers of organisms as a result of immunologic deficiency. Cf.:superinfection.

hyperinflation
hyperinflation (hi-per-in-fla′shun)

Overdistention of airways and alveoli, sometimes leading to emphysema, caused by obstructive lung disease; occurs reversibly with asthma, and can occur locally with aspiration of a foreign body with a subsequent ball-valve phenomenon. [hyper- + inflation]

hyperinosemia
hyperinosemia (hi′per-i′no-se′me-a, hi′per-in′o-)

A greatly increased quantity of fibrinogen in the circulating blood; under certain conditions, unusually large amounts of fibrin may be formed, thereby resulting in a greater degree of coagulability of the blood. SYN: hyperinosis. [hyper- + G. is (in-), fiber, + haima, blood]

hyperinosis
hyperinosis (hi-per-i-no′sis)

SYN: hyperinosemia.

hyperinsulinemia
hyperinsulinemia (hi′per-in′soo-lin-e′me-a)

SYN: hyperinsulinism.

hyperinsulinism
hyperinsulinism (hi′per-in′soo-lin-izm)

Increased levels of insulin in the plasma due to increased secretion of insulin by the beta cells of the pancreatic islets; decreased hepatic removal of insulin is a cause in some patients, although h. usually is associated with insulin resistance and is commonly found in obesity in association with varying degrees of hyperglycemia. SYN: hyperinsulinemia.
alimentary h. elevated levels of insulin in the plasma following ingestion of meals by individuals with abnormally rapid gastric emptying ( e.g., following gastroenterostomy or vagotomy); rapid glucose absorption leads to excessive insulin release which in turn can lead to a marked fall in blood glucose to hypoglycemic levels.

hyperinvolution
hyperinvolution (hi′per-in′vo-loo′shun)

SYN: superinvolution.

hyperisotonic
hyperisotonic (hi′per-i-so-ton′ik)

SYN: hypertonic.

hyperkalemia
hyperkalemia (hi′per-ka-le′me-a)

A greater than normal concentration of potassium ions in the circulating blood. SYN: hyperkaliemia, hyperpotassemia. [hyper- + Mod. L. kalium, potash, + G. haima, blood]

hyperkaliemia
hyperkaliemia (hi′per-kal-i-e′me-a)

SYN: hyperkalemia.

hyperkaluresis
hyperkaluresis (hi′per-kal-u-re′sis)

Excessive urinary excretion of potassium. [hyper- + Mod. L. kalium, potassium, + G. oureo, to urinate]

hyperkeratinization
hyperkeratinization (hi′per-ker′at-i-ni-za′shun)

SYN: hyperkeratosis.

hyperkeratosis
hyperkeratosis (hi′per-ker-a-to′sis)

Thickening of the horny layer of the epidermis or mucous membrane. SEE ALSO: keratoderma, keratosis. SYN: hyperkeratinization.
h. congenita SYN: ichthyosis vulgaris.
diffuse h. of palms and soles an autosomal dominant disorder with onset in early infancy; characterized by hyperkeratotic, scaling plaques and often hyperhidrosis on the palms and soles. SYN: Unna-Thost syndrome.
epidermolytic h. [MIM*144200] characterized by localized lesions, keratosis palmaris and plantaris, and elevated IgE, associated with h., hypergranulosis, and reticular degeneration in the upper epidermis; autosomal dominant inheritance, caused by mutation in the epidermolytic palmoplantar keratoderma gene (EPPK) on chromosome 17q. Generalized epidermolytic h. is present in bullous congenital ichthyosiform erythroderma. SYN: porcupine skin.
h. follicularis et parafollicularis discrete and confluent horny follicular plugs on a crateriform base, often occurring on the arms and legs in diabetics with renal failure; possibly a severe form of perforating folliculitis. SEE ALSO: perforating folliculitis. SYN: Kyrle disease.
generalized epidermolytic h. SYN: bullous congenital ichthyosiform erythroderma.
h. lenticularis perstans [MIM*144150] small hyperkeratotic papules on the dorsa of the feet and legs and occasionally elsewhere, with pinpoint keratotic papules of the palms and soles; onset in the third and fourth decades; an autosomal dominant trait. SYN: Flegel disease.

hyperketonemia
hyperketonemia (hi′per-ke′to-ne′me-a)

Elevated concentrations of ketone bodies in the blood.

hyperketonuria
hyperketonuria (hi′per-ke′to-noo′re-a)

Increased urinary excretion of ketonic compounds.

hyperkinemia
hyperkinemia (hi′per-ki-ne′me-a)

Increased circulation rate; increased volume flow through the circulation; supernormal cardiac output. [hyper- + G. kineo, to move, + haima, blood]

hyperkinesis
hyperkinesis, hyperkinesia (hi′per-ki-ne′sis, -ne′ze-a)

1. Excessive motility. 2. Excessive muscular activity. SYN: hypercinesis, hypercinesia, supermotility. [hyper- + G. kinesis, motion]

hyperkinetic
hyperkinetic (hi′per-ki-net′ik)

Pertaining to or characterized by hyperkinesia.

hyperlactation
hyperlactation (hi′per-lak-ta′shun)

SYN: superlactation.

hyperleukocytosis
hyperleukocytosis (hi′per-loo′ko-si-to′sis)

An unusually great increase in the number and proportion of leukocytes in the circulating blood or the tissues; i.e., much more than that ordinarily observed in most instances of leukocytosis.

hyperlexia
hyperlexia (hi-per-lek′se-a)

In mentally retarded children, the presence of relatively advanced reading ability. [hyper- + G. lexis, word, phrase]

hyperlipemia
hyperlipemia (hi′per-li-pe′me-a)

Elevated levels of lipids in the blood plasma. There are several types of h.. One is associated with a deficiency of δ-aminoadipic semialdehyde synthase. SEE ALSO: lipemia.
carbohydrate-induced h. SYN: type III familial hyperlipoproteinemia, type IV familial hyperlipoproteinemia.
combined fat- and carbohydrate-induced h. SYN: type V familial hyperlipoproteinemia.
familial combined h. familial hyperlipoproteinemia.
familial fat-induced h. SYN: type I familial hyperlipoproteinemia.
idiopathic h. SYN: type I familial hyperlipoproteinemia.
mixed h. SYN: type V familial hyperlipoproteinemia.

hyperlipidemia
hyperlipidemia (hi′per-lip-i-de′me-a)

SYN: lipemia.
mixed h. SYN: mixed hyperlipoproteinemia familial, type 5 h..
mixed hyperlipoproteinemia familial, type 5 h. elevations of VLDL and chylomicrons found in plasma. SYN: mixed h..

hyperlipoidemia
hyperlipoidemia (hi′per-lip-oy-de′me-a)

SYN: lipemia.

hyperlipoproteinemia
hyperlipoproteinemia (hi′per-lip′o-pro′te-in-e′me-a, -pro′ten-)

An increase in the lipoprotein concentration of the blood.
acquired h. nonfamilial h. that develops as a consequence of some primary disease, such as thyroid deficiency.
familial h. a group of diseases characterized by changes in concentration of β-lipoproteins and pre-β-lipoproteins and the lipids associated with them. See type I familial h., type II familial h., type III familial h., type IV familial h., type V familial h..
lipoprotein(a) h. elevated levels of lipoprotein(a) in the serum; associated with an increased risk of coronary disease.
type I familial h. [MIM*238600] h. characterized by the presence of large amounts of chylomicrons and triglycerides in the plasma when the patient has a normal diet, and their disappearance on a fat-free diet; low α- and β-lipoproteins on a normal diet, with increase on a fat-free diet; decreased plasma postheparin lipolytic activity; and low tissue lipoprotein lipase activity. It is accompanied by bouts of abdominal pain, hepatosplenomegaly, pancreatitis, and eruptive xanthomas; autosomal recessive inheritance; caused by mutation in the lipoprotein lipase gene (LPL) on chromosome 8p. SEE ALSO: familial lipoprotein lipase inhibitor. SYN: Bürger-Grütz syndrome, familial fat-induced hyperlipemia, familial hyperchylomicronemia, familial hypertriglyceridemia (1) , idiopathic hyperlipemia.
type II familial h. [MIM*143890 and MIM*144400] h. characterized by increased plasma levels of β-lipoproteins and cholesterol, elevated or normal levels of triglycerides; heterozygotes have mild lipid changes and are susceptible to atherosclerosis in middle age, but homozygotes have severe changes—often with generalized xanthomatosis, xanthelesma, corneal arcus, and frank clinical atherosclerosis as young adults. This disorder is divided into two classes, both inherited as autosomal dominant with homozygotes more severely affected than heterozygotes: 1) type IIA, which is characterized by elevated LDL but normal triglycerides and is due to a deficiency of the LDL receptor, a defect of the receptor or a modified LDL-apolipoprotein B-100, caused by mutation in the LDL receptor (LDLR) gene on chromosome 19p. SYN familial hypercholesterolemia; 2) type IIB has elevated LDL, cholesterol, and triglycerides, due to dysregulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase), the rate-controlling enzyme in cholesterol biosynthesis. SYN familial hyperbetalipoproteinemia, familial hypercholesterolemic xanthomatosis.
type III familial h. [MIM*107741] h. characterized by increased plasma levels of LDL, β-lipoproteins, pre-β-lipoproteins, cholesterol, phospholipids, and triglycerides; hypertriglyceridemia induced by a high carbohydrate diet, and glucose tolerance is abnormal; frequent eruptive xanthomas and atheromatosis, particularly coronary artery disease; biochemical defect lies in apolipoproteins; there are many varieties; one variety is caused by mutation in the APOE gene on chromosome 19q. SYN: carbohydrate-induced hyperlipemia, dysbetalipoproteinemia, familial hyperbetalipoproteinemia and hyperprebetalipoproteinemia, familial hypercholesterolemia with hyperlipemia.
type IV familial h. [MIM*144600] plasma levels of VLDL, pre-β-lipoproteins and triglycerides are increased on a normal diet, but β-lipoproteins, cholesterol, and phospholipids are normal; hypertriglyceridemia is induced by a high carbohydrate diet; may be accompanied by abnormal glucose tolerance and susceptibility to ischemic heart disease; probably autosomal dominant inheritance but genetic heterogeneity is a possibility. SYN: carbohydrate-induced hyperlipemia, familial hyperprebetalipoproteinemia, familial hypertriglyceridemia (2) .
type V familial h. [MIM*144650] h. characterized by increased plasma levels of chylomicrons, VLDL, pre-β-lipoproteins, and triglycerides, and slight rise of cholesterol on a normal diet, with β-lipoproteins normal; may be accompanied by bouts of abdominal pain, hepatosplenomegaly, susceptibility to atherosclerosis, and abnormal glucose tolerance; probably autosomal recessive inheritance. SYN: combined fat- and carbohydrate-induced hyperlipemia, familial hyperchylomicronemia with hyperprebetalipoproteinemia, mixed hyperlipemia.

hyperliposis
hyperliposis (hi′per-li-po′sis)

1. Excessive adiposity. 2. An extreme degree of fatty degeneration. [hyper- + G. lipos, fat]

hyperlithuria
hyperlithuria (hi′per-li-thu′re-a)

An excessive excretion of uric (lithic) acid in the urine.

hyperlogia
hyperlogia (hi-per-lo′je-a)

Morbid verbosity or loquacity. See logorrhea. [hyper- + G. logios, eloquent]

hyperlordosis
hyperlordosis (hi′per-lor-do′sis)

Extreme lordosis.

hyperlucent
hyperlucent (hi′-per-loo′sent)

A region on a chest film showing greater than normal film blackening from increased transmission of x-rays. See unilateral h. lung. [hyper- + L. lucens, shining, fr. luceo, to shine]

hyperlysinemia
hyperlysinemia (hi′per-li-si-ne′me-a) [MIM*238700]

A metabolic disorder characterized by mental retardation, convulsions, anemia, and asthenia; associated with an abnormal increase of the amino acid lysine in the circulating blood due to a deficiency of lysine-ketoglutarate reductase. One variant [MIM*268700] is associated with a deficiency of α-aminoadipic semialdehyde synthase, resulting in h. and saccharopinemia.

hyperlysinuria
hyperlysinuria (hi′per-li-si-noo′re-a)

The presence of abnormally high concentrations of lysine in the urine; a form of aminoaciduria that occurs in cystinuria, hepatolenticular degeneration, and the Fanconi syndrome.

hypermagnesemia
hypermagnesemia (hi′per-mag-ne-se′me-a)

An abnormally large concentration of magnesium in the blood serum.

hypermastia
hypermastia (hi-per-mas′te-a)

1. SYN: polymastia. 2. Excessively large mammary glands. [hyper- + G. mastos, breast]

hypermenorrhea
hypermenorrhea (hi′per-men-o-re′a)

Excessively prolonged or profuse menses. SYN: menorrhagia. [hyper- + G. men, month, + rhoia, flow]

hypermetabolism
hypermetabolism (hi′per-me-tab′o-lizm)

Heat production by the body above normal, as in thyrotoxicosis.
extrathyroidal h. a state of increased metabolic rate with normal levels of thyroid hormone production.

hypermetamorphosis
hypermetamorphosis (hi′per-met-a-mor′fo-sis)

Excessive and rapid change of ideas occurring in a mental disorder. See mania, manic-depressive, manic excitement. [hyper- + G. metamorphosis, transformation]

hypermethioninemia
hypermethioninemia (hi-per-meth-i-o-men-e-me-a)

Elevated levels of methionine in the sera.

hypermetria
hypermetria (hi-per-me′tre-a)

Ataxia characterized by overreaching a desired object or goal; usually seen with cerebellar disorders. Cf.:hypometria. [hyper- + G. metron, measure]

hypermetrope
hypermetrope (hi-per-met′rop)

SYN: hyperope.

hypermetropia
hypermetropia (hi′per-me-tro′pe-a)

SYN: hyperopia. [hyper- + G. metron, measure, + ops, eye]
index h. h. arising from decreased refractivity of the lens.

hypermnesia
hypermnesia (hi-per-ne′ze-a)

1. Extreme power of memory. 2. A capacity under hypnosis for immediate registration and precise recall of many more individual items than is thought possible under ordinary circumstances. Cf.:hypomnesia. [hyper- + G. mneme, memory]

hypermobility
hypermobility (hi′per-mo-bil′i-te)

Increased range of movement of joints, and joint laxity, occurring normally in children and adolescents or as a result of disease, e.g., Marfan or Ehlers-Danlos syndrome.

hypermorph
hypermorph (hi′per-morf)

1. Person whose sitting height is low in proportion to the standing height, owing to excessive length of limb. Cf.:hypomorph, ectomorph. 2. A mutant gene that causes an increase in the activity controlled by the gene. Cf.:hypomorph. [hyper- + G. morphe, form]

hypermyotrophy
hypermyotrophy (hi′per-mi-ot′ro-fe)

Muscular hypertrophy. [hyper- + G. mys, muscle, + trophe, nourishment]

hypernatremia
hypernatremia (hi′per-na-tre′me-a)

An abnormally high plasma concentration of sodium ions. [hyper- + natrium, + G. haima, blood]

hyperneocytosis
hyperneocytosis (hi′per-ne′o-si-to′sis)

Hyperleukocytosis in which there are considerable numbers of immature and young cells (especially in the granulocytic series); i.e., a “shift to the left” in the hemogram. SYN: hyperskeocytosis. [hyper- + G. neos, new, + kytos, cell, + -osis, condition]

hypernephroid
hypernephroid (hi-per-nef′royd)

Resembling or of the type of the adrenal gland. [hyper- + G. nephros, kidney, + eidos, appearance]

hypernoia
hypernoia (hi-per-noy′a)

1. Great rapidity of thought. 2. Excessive mental activity or imagination of the type seen in the manic phase of manic depression. See depression. [hyper- + G. noeo, to think]

hypernomic
hypernomic (hi-per-nom′ik)

Controlled to excess. [hyper- + G. nomos, law]

hypernutrition
hypernutrition (hi′per-noo-trish′un)

SYN: supernutrition.

hyperoncotic
hyperoncotic (hi′per-on-kot′ik)

Indicating an oncotic pressure higher than normal, e.g., of blood plasma.

hyperonychia
hyperonychia (hi′per-o-nik′e-a)

Hypertrophy of the nails. [hyper- + G. onyx, (onych-), nail]

hyperope
hyperope (hi′per-op)

One suffering from hyperopia. SYN: hypermetrope.

hyperopia
hyperopia (H) (hi-per-o′pe-a)

Longsightedness; that optical condition in which only convergent rays can be brought to focus on the retina. SYN: far sight, farsightedness, hypermetropia, long sight. [hyper- + G. ops, eye]
absolute h. manifest h. that cannot be overcome by an effort of accommodation.
axial h. h. due to shortening of the anteroposterior diameter of the globe of the eye.
curvature h. h. due to decreased refraction of the anterior ocular segment.
facultative h. SYN: manifest h..
latent h. the difference between total and manifest h..
manifest h. h. that can be compensated by accommodation. SYN: facultative h..
total h. (Ht) that which can be determined after complete paralysis of accommodation by means of a cycloplegic.

hyperopic
hyperopic (H) (hi-per-o′pik)

Pertaining to hyperopia.

hyperorality
hyperorality (hi′per-o-ral′i-te)

A condition in which inappropriate objects are placed in the mouth. [hyper- + L. os (or-), mouth]

hyperorexia
hyperorexia (hi′per-o-rek′se-a)

SYN: bulimia nervosa. [hyper- + G. orexis, appetite]

hyperornithinemia
hyperornithinemia (hi′per-orn′a-then-e-me-a)

Elevated levels of ornithine in the serum; sometimes associated with hyperammonemia and homocitrullinuria.

hyperorthocytosis
hyperorthocytosis (hi′per-or′tho-si-to′sis)

Hyperleukocytosis in which the relative percentages of the various types of white blood cells are within the normal range and immature forms are not observed. [hyper- + G. orthos, correct, + kytos, cell, + -osis, condition]

hyperosmia
hyperosmia (hi-per-oz′me-a)

An exaggerated or abnormally acute sense of smell. SYN: olfactory hyperesthesia, hyperesthesia olfactoria. [hyper- + G. osme, sense of smell]

hyperosmolality
hyperosmolality (hi′per-oz-mo-lal′i-te)

Increased osmotic concentration of a solution expressed as osmoles of solute per kilogram of serum water.

hyperosmolarity
hyperosmolarity (hi′per-oz-mo-lar′i-te)

An increase in the osmotic concentration of a solution expressed as osmoles of solute per liter of solution.

hyperosmotic
hyperosmotic (hi′per-oz-mot′ik)

1. Having an osmolality greater than another fluid, ordinarily assumed to be plasma or extracellular fluid. 2. Relating to increased osmosis.

hyperosteoidosis
hyperosteoidosis (hi′per-os-te-oy-do′sis)

Excessive formation of osteoid, as seen in rickets and osteomalacia.

hyperostosis
hyperostosis (hi′per-os-to′sis)

1. Hypertrophy of bone. 2. SYN: exostosis. [hyper- + G. osteon, bone, + -osis, condition]
ankylosing h. SYN: diffuse idiopathic skeletal h..
h. corticalis deformans [MIM*239000] marked irregular thickening of the skull and bone cortex, with thickening and widening of the shafts of long bones and high serum alkaline phosphatase; autosomal recessive inheritance.
diffuse idiopathic skeletal h. (DISH) a generalized spinal and extraspinal articular disorder characterized by calcification and ossification of ligaments, particularly of the anterior longitudinal ligament; distinct from ankylosing spondylitis or degenerative joint disease. SYN: ankylosing h., Forestier disease, hyperostotic spondylosis.
flowing h. SYN: rheostosis.
h. frontalis interna abnormal deposition of bone on the inner aspect of the os frontale, visible by x-ray; may be a part of Morgagni syndrome.
generalized cortical h. SYN: van Buchem syndrome.
infantile cortical h. [MIM*114000] neonatal subperiosteal bone formation over many bones, especially the mandible, clavicles, and the shafts of long bones; it follows fever, usually appearing before 6 months of age and disappearing during childhood; familial cases are inherited as autosomal dominant. SYN: Caffey disease, Caffey syndrome, Caffey-Silverman syndrome.
streak h. SYN: rheostosis.

hyperovarianism
hyperovarianism (hi′per-o-va′re-an-izm)

Sexual precocity in young girls due to premature maturation of the hypotholomic-pituitary axis and development of ovaries accompanied by the secretion of ovarian hormones. SYN: true precocious puberty.

hyperoxaluria
hyperoxaluria (hi′per-ok-sa-loo′re-a)

Presence of an unusually large amount of oxalic acid or oxalates in the urine; renal stones may occur. SYN: oxaluria.
primary h. and oxalosis [MIM*259900 & MIM*260000] a metabolic disorder, usually evident clinically in the first decade of life, characterized by calcium oxalate nephrocalcinosis and nephrolithiasis, extrarenal oxalosis, and increased urinary output of oxalic and glycolic acids, leading to progressive renal failure and uremia. Type I is due to a deficiency in alanine-glyoxylate aminotransferase and type II to a deficiency in D-glycerate dehydrogenase; the latter is a milder disease with a better long-term prognosis for renal function. Both types are inherited as autosomal recessive, caused by mutation in the alanine-glyoxylate aminotransferase gene (AGXT) on 2q.

hyperoxia
hyperoxia (hi-per-ok′se-a)

1. An increased amount of oxygen in tissues and organs. 2. A greater oxygen tension than normal, such as that produced by breathing air or oxygen at pressures greater than 1 atmosphere.

hyperoxidation
hyperoxidation (hi′per-oks-i-da′shun)

Excessive oxidation.

hyperpancreatism
hyperpancreatism (hi′per-pan′kre-a-tizm)

A condition of increased activity of the pancreas, trypsin being in excess among the enzymes.

hyperparasite
hyperparasite (hi-per-par′a-sit)

A secondary parasite capable of development within a previously existing parasite.

hyperparasitism
hyperparasitism (hi-per-par′a-sit-izm)

A condition in which a secondary parasite develops within a previously existing parasite. SYN: biparasitism.

hyperparathyroidism
hyperparathyroidism (hi′per-par-a-thi′royd-izm)

A condition due to an increase in the secretion of the parathyroids, causing elevated serum calcium, decreased serum phosphorus, and increased excretion of both calcium and phosphorus, calcium stones and sometimes generalized osteitis fibrosa cystica.
primary h. h. due to neoplasms or idiopathic hyperplasia of the parathyroid glands.
secondary h. h. that arises as a result of disordered metabolism producing hypocalcemia, as in chronic uremia due to renal disease, malabsorption, rickets, or osteomalacia; associated with hyperplasia of the parathyroid glands.

hyperparotidism
hyperparotidism (hi′per-pa-rot′i-dizm)

Increased activity of the parotid glands.

hyperpathia
hyperpathia (hi-per-path′e-a)

Exaggerated subjective response to painful stimuli, with a continuing sensation of pain after the stimulation has ceased. [hyper- + G. pathos, suffering]

hyperpepsia
hyperpepsia (hi-per-pep′se-a)

1. Abnormally rapid digestion. 2. Impaired digestion with hyperchlorhydria. [hyper- + G. pepsis, digestion]

hyperpepsinia
hyperpepsinia (hi′per-pep-sin′e-a)

An excess of pepsin in the gastric juice.

hyperperistalsis
hyperperistalsis (hi′per-per-i-stal′sis)

Excessive rapidity of the passage of food through the stomach and intestine.

hyperphagia
hyperphagia (hi-per-fa′je-a)

Gluttony; overeating. [hyper- + G. phagein, to eat]

hyperphalangism
hyperphalangism (hi′per-fa-lan′jizm)

Presence of a supernumerary phalanx in a finger or toe. SYN: polyphalangism.

hyperphenylalaninemia
hyperphenylalaninemia (hi′per-fen′il-al-a-ni-ne′me-a)

The presence of abnormally high blood levels of phenylalanine, which may or may not be associated with elevated tyrosine levels, in newborn infants (premature and full-term), associated with the heterozygous state of phenylketonuria, maternal phenylketonuria, or transient deficiency of phenylalanine hydroxylase or p-hydroxyphenylpyruvic acid oxidase.
malignant h. 1. dHPR-deficient form; an inherited disorder in which there is an absence or deficiency of dihydropteridine reductase (DHPR); this results in impaired regeneration of tetrahydrobiopterin, causing an elevation in phenylalanine levels; 2. gTP-CH form; an inherited disorder in which there is a deficiency of guanosine triphosphate cyclohydrolase, an enzyme used in the biosynthesis of tetrahydrobiopterin; 3. 6-PTS form; an inherited disorder in which there is a deficiency of 6-pyruvoyl tetrahydropterin synthase, an enzyme that participates in the biosynthesis of tetrahydrobiopterin. SYN: nonclassical phenylketonuria.
non-PKU h. a benign phenotype in which phenylalanine monooxygenase is deficient but is greater than 1% of normal levels.

hyperphonesis
hyperphonesis (hi′per-fo-ne′sis)

An increase in the percussion sound or of the voice sound in auscultation. [hyper- + G. phonesis, a sounding]

hyperphonia
hyperphonia (hi′per-fo′ne-a)

Excessive effort in voice production characterized by loudness and undue tension of the vocal muscles. [hyper- + G. phone, sound, voice]

hyperphoria
hyperphoria (hi-per-fo′re-a)

A tendency of the visual axis of one eye to deviate upward, prevented by binocular vision. [hyper- + G. phora, motion]

hyperphosphatasemia
hyperphosphatasemia (hi′per-fos′fa-ta-se′me-a)

Abnormally high content of alkaline phosphatase in the circulating blood. SEE ALSO: hyperphosphatasia.

hyperphosphatasia
hyperphosphatasia (hi′per-fos-fa-ta′ze-a) [MIM*239000 and MIM*239300]

A skeletal dysplasia characterized by dwarfism, macrocranium, expansion of the diaphyses of tubular bones with multiple fractures, patchy osteosclerosis, leg bowing, and occasionally mental retardation; serum alkaline phosphatase is elevated; autosomal recessive inheritance.

hyperphosphatemia
hyperphosphatemia (hi′per-fos-fa-te′me-a)

Abnormally high concentration of phosphates in the circulating blood.

hyperphosphaturia
hyperphosphaturia (hi′per-fos-fa-too′re-a)

An increased excretion of phosphates in the urine.

hyperphrenia
hyperphrenia (hi-per-fre′ne-a)

Rarely used term for an excessive degree of intellectual activity; a form of mania. [hyper- + G. phren, mind]

hyperpiesis
hyperpiesis, hyperpiesia (hi′per-pi-e′sis, -pi-e′ze-a)

SYN: hypertension. [hyper- + G. piesis, pressure]

hyperpietic
hyperpietic (hi-per-pi-et′ik)

Relating to or marked by high blood pressure.

hyperpigmentation
hyperpigmentation (hi′per-pig-men-ta′shun)

An excess of pigment in a tissue or part.

hyperpipecolatemia
hyperpipecolatemia (hi-per-pip′e-ko-la-te′me-a)

A metabolic disorder in which serum concentration of pipecolic acid is greatly increased; characterized by hepatomegaly and progressive, generalized demyelination of the nervous system. SYN: hyperpipecolic acidemia.

hyperpipecolic acidemia
hyperpipecolic acidemia (hi′per-pi′pe-ko-lik)

SYN: hyperpipecolatemia.

hyperpituitarism
hyperpituitarism (hi′per-pi-too′i-ta-rizm)

Excessive production of anterior pituitary hormones, especially growth hormone; may result in gigantism or acromegaly.

hyperplasia
hyperplasia (hi-per-pla′zhe-a)

An increase in number of normal cells in a tissue or organ, excluding tumor formation, whereby the bulk of the part or organ may be increased. SEE ALSO: hypertrophy. SYN: numerical hypertrophy, quantitative hypertrophy. [hyper- + G. plasis, a molding]
adenomatous h. SYN: complex endometrial h..
angiofollicular mediastinal lymph node h. SYN: benign giant lymph node h..
angiolymphoid h. with eosinophilia solitary or multiple small benign cutaneous erythematous nodules, occurring mainly on the head and neck in young adults, characterized by dermal proliferation of blood vessels with vacuolated histiocytoid endothelial cells and with a varied infiltrate of eosinophils, lymphocytes which may form follicles, and histiocytes. SYN: Kimura disease.
atypical endometrial h. increase in the number of glands, which have little, if any, stroma separating them but retain an orderly architecture distinguishing them from adenocarcinoma.
atypical melanocytic h. proliferation of melanocytes showing nuclear atypicality, especially as scattered single cells high in the epidermis; interpreted by some pathologists as malignant melanoma in situ.
basal cell h. increase in the number of cells in an epithelium resembling the basal cells.
benign giant lymph node h. solitary masses of lymphoid tissue containing concentric perivascular aggregates of lymphocytes, occurring usually in the mediastinum or hilar region of young adults; similar changes have been reported outside the mediastinum and, if associated with interfollicular sheets of plasma cells, may progress to lymphoma or plasmacytoma. SYN: angiofollicular mediastinal lymph node h., Castleman disease.
benign prostatic h. progressive enlargement of the prostate due to h. of both glandular and stromal components, typically beginning in the fifth decade and sometimes causing obstructive or irritative symptoms, or both; does not evolve into cancer.
cementum h. SYN: hypercementosis.
complex endometrial h. closely packed endometrial glands, with a single layer of cells with slightly enlarged nuclei that are generally basally located. SYN: adenomatous h..
congenital adrenal h. a group of autosomal recessively inherited disorders associated with a deficiency of one of the enzymes involved in cortisol biosynthesis, resulting in elevation of ACTH levels and overproduction and accumulation of cortisol precursors proximal to the block; androgens are produced in excess, causing virilization. The most common disorder is the 21-hydroxylase deficiency, caused by mutation in the cytochrome P450 21-hydroxylase gene (CYP21) on chromosome 6p. There are four major types with some clinical similarities but distinctive genetic and biochemical differences: 1) the salt-losing form [MIM*201710, MIM*201810, and MIM*201910], 2) the hypertensive form [MIM*202010 and MIM*202110], 3) the simple virilizing form [MIM*201910], and 4) the pseudohermaphrodite form [MIM*201810 and MIM*202110].
congenital virilizing adrenal h. a series of inherited inborn errors of metabolism with h. of the adrenal cortex and overproduction of virilizing hormones. Most common forms are due to partial or complete 21-hydroxylase deficiency, leading to increased ACTH production by the pituitary, stimulating adrenal growth and function. Severe form is characterized by salt-losing state.
cystic h. formation of multiple retention cysts from obstruction of ducts or glands by h. of the lining epithelium, as in fibrocystic disease of the breast and metropathia hemorrhagica.
cystic h. of the breast SYN: fibrocystic condition of the breast.
denture h. SYN: inflammatory fibrous h..
ductal h. h. characterized by intraductal proliferation of epithelial cells, e.g., in the breast.
endometrial h. increase in the number of endometrial glands, usually secondary to hyperestrinism; classified as simple h., complex h., or complex h. with atypia; the latter may progress to adenocarcinoma.
fibromuscular h. thickening of arterial media by fibrosis and muscular h., usually involving the renal arteries and causing multifocal stenosis and hypertension; a variety of fibromuscular dysplasia.
focal epithelial h. multiple soft nodular lesions of the lips, buccal mucosa, tongue, and other oral sites in children and adolescents; lesions spontaneously regress after a period of several months, and have been attributed to papovaviruses. SYN: Heck disease.
gingival h. gingival enlargement due to proliferation of fibrous connective tissue. SYN: gingival proliferation.
inflammatory fibrous h. overgrowth of tissue in the mucobuccal or labial fold, induced by chronic trauma from ill-fitting dentures. SYN: denture h., epulis fissuratum.
inflammatory papillary h. closely arranged papules of the palatal mucosa underlying an ill-fitting denture. SYN: palatal papillomatosis.
intravascular papillary endothelial h. a benign florid papillary endothelial proliferation within the veins of the skin or subcutis, less often in visceral blood vessels.
neuronal h. increased numbers of ganglion cells with myenteric plexus h. and increased acetylcholinesterase activity in nerves of the mucosa and submucosa. Clinically, neuronal h. mimics Hirschsprung disease. Similar findings are seen in patients with multiple endocrine neoplasia syndrome, type IIB, and in neurofibromatosis. SYN: hyperganglionosis, neuronal intestinal dysplasia.
nodular h. of prostate glandular and stromal h. occurring very commonly in the transition zone and anterior fibromuscular stroma of older men, forming nodules that may increasingly obstruct the urethra.
nodular regenerative h. SYN: nodular transformation of the liver.
pseudoepitheliomatous h., pseudocarcinomatous h. a benign marked increase and downgrowth of epidermal cells, observed in chronic inflammatory dermatoses and over some dermal neoplasms and nevi; microscopically, it resembles well-differentiated squamous cell carcinoma.
senile sebaceous h. h. of mature sebaceous glands, forming a nodule on the skin of the face or forehead in elderly persons.
simple endometrial h. increase in the amount of endometrial tissue, with glands separated by abundant stroma. SYN: Swiss cheese endometrium.
squamous cell h. increase in the number of cells in a squamous epithelium. SYN: hypertrophic dystrophy.
verrucous h. h. of the oral mucosa, occurring in the elderly, characterized by sharp or blunt upward papillary projections of squamous epithelium.

hyperplastic
hyperplastic (hi-per-plas′tik)

Relating to hyperplasia.

hyperpnea
hyperpnea (hi-per-ne′a, hi-perp′ne-a)

Breathing that is deeper and more rapid than is normal at rest. [hyper- + G. pnoe, breathing]

hyperpolarization
hyperpolarization (hi′per-po′lar-i-za′shun)

An increase in polarization of membranes of nerves or muscle cells; the reverse change from that associated with excitatory action.

hyperpotassemia
hyperpotassemia (hi′per-po-tas-e′me-a)

SYN: hyperkalemia.

hyperprebetalipoproteinemia
hyperprebetalipoproteinemia (hi′per-pre-ba′ta-lip-o-pro′te-in-e′me-a, -pro′ten-)

Increased concentrations of pre-β-lipoproteins in the blood.
familial h. SYN: type IV familial hyperlipoproteinemia.

hyperprochoresis
hyperprochoresis (hi′per-pro-kor-e′sis)

Rarely used term for hyperperistalsis. [hyper- + G. pro-choreo, to go forward]

hyperproinsulinemia
hyperproinsulinemia (hi′per-pro-in′sul-i-ne′me-a)

Elevated plasma levels of proinsulin or proinsulin-like material.

hyperprolactinemia
hyperprolactinemia (hi′per-pro-lak-ti-ne′me-a)

Elevated levels of prolactin in the blood, which is a normal physiological reaction during lactation, but pathological otherwise; prolactin may also be elevated in cases of certain pituitary tumors, and amenorrhea is often present.

hyperprolinemia
hyperprolinemia (hi′per-pro-li-ne′me-a) [MIM*239500 & MIM*239510]

A metabolic disorder characterized by enhanced plasma proline concentrations and urinary excretion of proline, hydroxyproline, and glycine; autosomal recessive inheritance. Type I h. is associated with a deficiency of proline oxidase and renal disease; Type II h. is associated with a deficiency of Δ-pyrroline-5-carboxylate dehydrogenase, mental retardation, and convulsions and is caused by mutation in the δ-pyrroline 5 carboxylate gene (P5CD) on 1p.

hyperproteinemia
hyperproteinemia (hi′per-pro′te-in-e′me-a, -pro′ten-)

An abnormally large concentration of protein in plasma.

hyperproteosis
hyperproteosis (hi′per-pro-te-o′sis)

The condition due to an excessive amount of protein in the diet.

hyperpyretic
hyperpyretic (hi′per-pi-ret′ik)

Relating to hyperpyrexia. SYN: hyperpyrexial.

hyperpyrexia
hyperpyrexia (hi′per-pi-rek′se-a)

Extremely high fever. [hyper- + G. pyrexis, feverishness]
fulminant h. SYN: malignant hyperthermia.
heat h. SYN: heatstroke.
malignant h. SYN: heatstroke.

hyperpyrexial
hyperpyrexial (hi′per-pi-rek′se-al)

SYN: hyperpyretic.

hyperreflexia
hyperreflexia (hi′per-re-flek′se-a)

A condition in which the deep tendon reflexes are exaggerated.
detrusor h. SYN: detrusor instability.

hyperresonance
hyperresonance (hi-per-rez′o-nans)

1. An extreme degree of resonance. 2. Resonance increased above the normal, and often of lower pitch, on percussion of an area of the body; occurs in the chest due to overinflation of the lung as in emphysema or pneumothorax and in the abdomen over distended bowel.

hypersalemia
hypersalemia (hi′per-sal-e′me-a)

Obsolete term for an increase in the salt content of the circulating blood.

hypersaline
hypersaline (hi-per-sa′len, -sa′lin)

Marked by increased salt concentrations in a saline solution.

hypersalivation
hypersalivation (hi′per-sal-i-va′shun)

Increased salivation.

hypersarcosinemia
hypersarcosinemia (hi′per-sar-ko-si-ne′me-a)

SYN: sarcosinemia.

hypersecretion hypersecretion

Excessive secretion of any tissue or gland.
gastric h. excessive formation of gastric juice, especially the acid component.

hypersegmentation
hypersegmentation

Excessive division of a tissue or part into segments.
hereditary h. of neutrophils an autosomal dominant condition characterized by neutrophil h.; affected persons are asymptomatic.

hypersensitivity
hypersensitivity (hi′per-sen-si-tiv′i-te)

Abnormal sensitivity, a condition in which there is an exaggerated response by the body to the stimulus of a foreign agent. See allergy.
contact h. 1. SYN: contact dermatitis. 2. SYN: delayed reaction.
delayed h. 1. SYN: cell-mediated immunity. 2. SYN: delayed reaction. 3. a cell-mediated response that occurs in immune individuals peaking at 24–48 hours after challenge with the same antigen used in an initial challenge. The interaction of T-helper I lymphocytes with MHC class II positive antigen-presenting cells initiates the response. This interaction induces the T helper 1 and macrophages at the site to secrete cytokines, which are the major players in the reaction. Called tuberculin-type h..
immediate h. an exaggerated immune response mediated by antibodies occurring within minutes after exposing a sensitized individual to the approximate antigen; also called Type I h.. Clinical symptoms include atopic allergy and systemic anaphylaxis. The antigen induces IgE antibodies, which bind to most cells and basophils. Subsequent exposure to antigen causes binding with the cytophilic IgE resulting in the release of mediators. See allergy.
tuberculin-type h. SYN: delayed reaction.

hypersensitization
hypersensitization (hi′per-sen′si-ti-za′shun)

The immunological process by which hypersensitivity is induced.

hyperserotonemia
hyperserotonemia (hi′per-ser′o-to-ne′me-a)

Unusually large amounts of serotonin in the circulating blood; probable cause of some of the symptoms and signs in the carcinoid syndrome.

hyperskeocytosis
hyperskeocytosis (hi′per-ske′o-si-to′sis)

SYN: hyperneocytosis. [G. skaios, left, + kytos, cell, + -osis, condition]

hypersomatotropism
hypersomatotropism (hi′per-so′ma-to-tro′pizm)

A state characterized by abnormally enhanced secretion of pituitary growth hormone (somatotropin).

hypersomnia
hypersomnia (hi-per-som′ne-a)

A condition in which sleep periods are excessively long, but the person responds normally in the intervals; distinguished from somnolence. [hyper- + L. somnus, sleep]

hypersonic
hypersonic (hi-per-son′ik)

Pertaining to or characterized by supersonic speeds of Mach 5 or greater. While any speed above the speed of sound may be referred to as supersonic, speeds of Mach 5 or greater are specifically referred to as h.. [hyper- + L. sonus, sound]

hypersphyxia
hypersphyxia (hi-per-sfik′se-a)

A condition of high blood pressure and increased circulatory activity. [hyper- + G. sphyxis, pulse]

hypersplenism
hypersplenism (hi-per-splen′izm)

Any of a group of conditions in which the cellular components of the blood or platelets are removed at an abnormally high rate by the spleen, resulting in low circulating levels.

hypersteatosis
hypersteatosis (hi′per-ste-a-to′sis)

Excessive sebaceous secretion.

hypersthenia
hypersthenia (hi-per-sthe′ne-a)

Excessive tension or strength. [hyper- + G. sthenos, strength]

hypersthenic
hypersthenic (hi-per-sthen′ik)

Pertaining to or marked by hypersthenia.

hypersthenuria
hypersthenuria (hi′per-sthen-u′re-a)

Excretion of urine of unusually high specific gravity and concentration of solutes, resulting usually from loss or deprivation of water. [hyper- + G. sthenos, strength, + ouron, urine]

hypersusceptibility
hypersusceptibility (hi′per-su-sep-ti-bil′i-te)

Increased susceptibility or response to an infective, chemical, or other agent.

hypersystole
hypersystole (hi-per-sis′to-le)

Abnormal force or duration of the cardiac systole.

hypersystolic
hypersystolic (hi′per-sis-tol′ik)

Relating to or marked by hypersystole.

hypertelorism
hypertelorism (hi-per-tel′or-izm)

Abnormal distance between two paired organs. [hyper- + G. tele, far off, + horizo, to separate, fr. horos, a boundary]
Bixler type h. accompanying features are microtia and clefting of the lip, palate, and nose, mental deficiency, atresia of the auditory canals, ectopic kidneys, and thenar hypoplasia; autosomal recessive inheritance
canthal h. SYN: telecanthus.
ocular h. [MIM*145400] increased width between the eyes due to an arrest in development of the greater wings of the sphenoid, thus fixing the orbits in the widely separated fetal position; autosomal dominant inheritance. Ocular h. is a feature of many syndromes. A distinct form [MIM*145410] shows other congenital defects such as hypospadias and esophageal anomalies. SEE ALSO: faciodigitogenital dysplasia. SYN: Greig syndrome, Opitz BBB syndrome, Opitz G syndrome.

hypertensin
hypertensin (hi-per-ten′sin)

Former name for angiotensin.

hypertensinogen
hypertensinogen (hi′per-ten-sin′o-jen)

Former name for angiotensinogen.

hypertension hypertension (hi′per-ten′shun)

High blood pressure; transitory or sustained elevation of systemic arterial blood pressure to a level likely to induce cardiovascular damage or other adverse consequences. H. has been arbitrarily defined as a systolic blood pressure above 140 mm Hg or a diastolic blood pressure above 90 mm Hg. Consequences of uncontrolled h. include retinal vascular damage (Keith-Wagener-Barker changes), cerebrovascular disease and stroke, left ventricular hypertrophy and failure, myocardial infarction, dissecting aneurysm, and renovascular disease. An underlying disorder ( e.g., renal disease, Cushing syndrome, pheochromocytoma) is identified in fewer than 10% of all cases of h.. The remainder, traditionally labeled “essential” h., probably arise from a variety of disturbances in normal pressure-regulating mechanisms (which involve baroreceptors, autonomic influences on the rate and force of cardiac contraction and vascular tone, renal retention of salt and water, formation of angiotensin II under the influence of renin and angiotensin-converting enzyme, and other factors known and unknown), and most are probably genetically conditioned. SYN: hyperpiesis, hyperpiesia. [hyper- + L. tensio, tension] Because of its wide prevalence and its impact on cardiovascular health, h. is a major cause of disease and death in industrialized societies. It is estimated that 50–70 million Americans, including about 50% of all people over age 60, have h., but that only about one-third of these are aware of their condition and are under appropriate treatment. H. causes 35,000 deaths annually in the U.S., and is a contributing factor in a further 180,000 deaths. It is associated with a 3-fold increase in the risk of heart attack and a 7- to 10-fold increase in the risk of stroke. The prevalence of h. and the incidence of nonfatal and fatal consequences are substantially higher in African-Americans. Although people with extremely high diastolic pressure may experience headache, dizziness, and even encephalopathy, uncomplicated h. seldom causes symptoms. Hence the diagnosis of h. is usually made by screening apparently healthy persons or those under treatment for another condition. Risk factors for h. include a family history of h., African-American race, advancing age, the postmenopausal state, excessive dietary sodium, obesity, excessive use of alcohol, sedentary lifestyle, and chronic emotional stress. Treatment options include lifestyle changes (maintenance of healthful weight; at least 30 minutes of aerobic exercise several days a week; limitation of sodium intake to 2.4 g daily and of ethanol to 1 oz daily; consumption of adequate potassium, calcium, and magnesium; and avoidance of excessive emotional stress) and a broad range of drugs, including diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, α₁-adrenergic antagonists, centrally acting alpha-agonists, and others. In recent decades, early detection and aggressive treatment of h. have reduced associated morbidity and mortality. Current practice standards call for still more diligent management, including prevention through avoidance of known risk factors, particularly in persons with a family history of h., and control of cofactors known to increase the risk of cardiovascular damage in persons with h. (smoking, hypercholesterolemia, diabetes mellitus). Some studies suggest that the goal of treatment should be a diastolic blood pressure of 80 or lower.
accelerated h. h. advancing rapidly with increasing blood pressure and associated with acute and rapidly worsening signs and symptoms.
adrenal h. h. due to an adrenal medullary pheochromocytoma or to hyperactivity or functioning tumor of the adrenal cortex.
benign h. h. that runs a relatively long and symptomless course.
borderline h. by consensus, that blood pressure zone between highest acceptable “normal” blood pressure and hypertensive blood pressure. The Framingham Heart Study defines this as pressures between 140 and 160 mm Hg systolic and 90 and 95 mm Hg diastolic.
episodic h. h. manifest intermittently, triggered by anxiety or emotional factors. SYN: paroxysmal h..
essential h. h. without known cause. SYN: idiopathic h., primary h..
gestational h. h. during pregnancy in a previously normotensive woman or aggravation of h. during pregnancy in a hypertensive woman. SYN: pregnancy-induced h..
Goldblatt h. increased blood pressure following obstruction of blood flow to one kidney.
idiopathic h. SYN: essential h..
labile h. frequently changing levels of elevated blood pressure.
malignant h. severe h. that runs a rapid course, causing necrosis of arteriolar walls in kidney, retina, etc.; hemorrhages occur, and death most frequently is caused by uremia or rupture of a cerebral vessel.
pale h. h. with pallor of the skin, a severe form with pronounced constriction of peripheral vessels.
paroxysmal h. SYN: episodic h..
portal h. h. in the portal system as seen in cirrhosis of the liver and other conditions causing obstruction to the portal vein.
postpartum h. increased blood pressure immediately following the completion of labor.
pregnancy-induced h. SYN: gestational h..
primary h. SYN: essential h..
pulmonary h. h. in the pulmonary circuit; may be primary, or secondary to pulmonary or cardiac disease, e.g., fibrosis of the lung or mitral stenosis.
renal h. h. secondary to renal disease.
renovascular h. h. produced by renal arterial obstruction.
secondary h. arterial h. produced by a known cause, e.g., hyperthyroidism, kidney disease, etc., in contrast to primary h. that is of unknown cause.
systemic venous h. increased pressure in the veins ultimately leading to the right atrium nearly always due to disease of the right heart or pericardium but occasionally due to blockade of one or both venae cavae.

hypertensive
hypertensive (hi-per-ten′siv)

1. Marked by an increased blood pressure. 2. Denoting a person suffering from high blood pressure.

hypertensor
hypertensor (hi-per-ten′ser, -sor)

SYN: pressor.

hypertestoidism
hypertestoidism (hi-per-tes′toyd-izm)

Hypergonadism in the male, characterized by proliferation of Leydig cells with excessive production of testosterone.

hyperthecosis
hyperthecosis (hi′per-the-ko′sis)

Diffuse hyperplasia of the theca cells of the graafian follicles.
stromal h. condition in which luteinized cells are present in ovarian stroma at a distance from follicular structures.

hyperthelia
hyperthelia (hi-per-the′le-a)

SYN: polythelia. [hyper- + G. thele, nipple]

hyperthermalgesia
hyperthermalgesia (hi′per-ther-mal-je′ze-a)

Extreme sensitiveness to heat. [hyper- + G. therme, heat, + algesis, pain]

hyperthermia
hyperthermia (hi-per-ther′me-a)

Therapeutically induced hyperpyrexia. [hyper- + G. therme, heat]
malignant h. rapid onset of extremely high fever with muscle rigidity, precipitated by exogenous agents in genetically susceptible persons, especially by halothane or succinylcholine. Cf.:futile cycle. SYN: fulminant hyperpyrexia.

hyperthermoesthesia
hyperthermoesthesia (hi-per-ther′mo-es-the′ze-a)

Extreme sensitiveness to heat. [hyper- + G. therme, heat, + aisthesis, feeling]

hyperthrombinemia
hyperthrombinemia (hi′per-throm-bi-ne′me-a)

An abnormal increase of thrombin in the blood, frequently resulting in a tendency to intravascular coagulation.

hyperthymia
hyperthymia (hi-per-thi′me-a)

State of overactivity, greater than average and less than the overactivity of the manic state of manic-depressive disorder. [hyper- + G. thymos, soul, thought]

hyperthymic
hyperthymic (hi-per-thi′mik)

1. Pertaining to hyperthymia. 2. Pertaining to hyperthymism.

hyperthymism
hyperthymism (hi-per-thi′mizm)

Excessive activity of the thymus gland; formerly postulated to be a causal factor in certain instances of unexpected and sudden death, such as status thymicolymphaticus. SYN: hyperthymization.

hyperthymization
hyperthymization (hi′per-thi-mi-za′shun)

SYN: hyperthymism.

hyperthyrea
hyperthyrea (hi′per-thi-re-a)

SYN: hyperthyroidism.

hyperthyroidism
hyperthyroidism (hi-per-thi′royd-izm)

An abnormality of the thyroid gland in which secretion of thyroid hormone is usually increased and is no longer under regulatory control of hypothalamic-pituitary centers; characterized by a hypermetabolic state, usually with weight loss, tremulousness, elevated plasma levels of thyroxin and/or triiodothyronine, and sometimes exophthalmos; may progress to severe weakness, wasting, hyperpyrexia, and other manifestations of thyroid storm; often associated with exophthalmos (Graves disease). SEE ALSO: thyrotoxicosis. SYN: hyperthyrea, thyroidism (1) , thyrointoxication.
hereditary h. a rare inherited (autosomal dominant) disorder with constitutive stimulation of the thyrocytes.
iodine-induced h. SYN: Jod-Basedow phenomenon.
masked h. h. occurring without the usual manifestations, especially lack of hyperactivity and eye findings, often with hypoactivity, even somnolence. Manifestation can be limited to heart failure.
ophthalmic h. SYN: Graves disease.
primary h. h. due to a disorder originating within the thyroid gland, in contrast to one of pituitary origin; may be due to generalized overactivity of the gland, to a localized hyperactive nodule, or to circulating antibody, which stimulates the gland (long-acting thyroid stimulator).
secondary h. h. due to stimulation of the thyroid gland by an excess of thyrotrophin secreted by the pituitary gland.

hyperthyroxinemia
hyperthyroxinemia (hi′per-thi-rok-si-ne′me-a)

An elevated thyroxine concentration in the blood.

hypertonia
hypertonia (hi-per-to′ne-a)

Extreme tension of the muscles or arteries. SYN: hypertonicity (1) . [hyper- + G. tonos, tension]
h. polycythemica a form of polycythemia without a prominent degree of splenomegaly, but with increased blood pressure.
sympathetic h. overfunction of the sympathetic nervous system, often experienced as anxiety.

hypertonic
hypertonic (hi-per-ton′ik)

1. Having a greater degree of tension. SYN: spastic (1) . 2. Having a greater osmotic pressure than a reference solution, which is ordinarily assumed to be blood plasma or interstitial fluid; more specifically, refers to a fluid in which cells shrink. SYN: hyperisotonic.

hypertonicity
hypertonicity (hi′per-to-nis′i-te)

1. SYN: hypertonia. 2. An increased effective osmotic pressure of body fluids.

hypertrichiasis
hypertrichiasis (hi′per-tri-ki′a-sis)

SYN: hypertrichosis.

hypertrichophrydia
hypertrichophrydia (hi′per-trik-o-fri′de-a)

Excessively thick eyebrows. [hyper- + G. thrix, hair, + ophrys, eyebrow]

hypertrichosis
hypertrichosis (hi′per-tri-ko′sis)

Growth of hair in excess of the normal. SEE ALSO: hirsutism. SYN: hypertrichiasis. [hyper- + G. trichosis, being hairy]
h. lanuginosa excessive growth of lanugo hair associated with internal malignancy.
nevoid h. congenital growth of hair abnormal for its site, texture, color, or length; often associated with congenital melanocytic nevi.
h. partialis abnormally excessive hair growth in patches in unusual areas.
h. universalis generalized excessive hair growth.

hypertriglyceridemia
hypertriglyceridemia (hi′per-tri-glis′er-i-de′me-a)

Elevated triglyceride concentration in the blood.
familial h. 1. SYN: type I familial hyperlipoproteinemia. 2. SYN: type IV familial hyperlipoproteinemia.

hypertroph
hypertroph (hi′per-trof)

A microorganism that requires living cells to supply the enzyme systems necessary for growth and reproduction.

hypertrophia
hypertrophia (hi-per-tro′fe-a)

SYN: hypertrophy.

hypertrophic
hypertrophic (hi-per-trof′ik)

Relating to or characterized by hypertrophy.

hypertrophy
hypertrophy (hi-per′tro-fe)

General increase in bulk of a part or organ, not due to tumor formation. Use of the term may be restricted to denote greater bulk through increase in size, but not in number, of cells or other individual tissue elements. Cf.:hyperplasia. SYN: hypertrophia. [hyper- + G. trophe, nourishment]
adaptive h. thickening of the walls of a hollow organ, like the urinary bladder, when there is obstruction to outflow.
benign prostatic h. erroneous term that is often considered a synonym of nodular hyperplasia of prostate.
compensatory h. increase in size of an organ or part of an organ or tissue, when called upon to do additional work or perform the work of destroyed tissue or of a paired organ.
compensatory h. of the heart thickening of the walls of the heart in response to vascular, valvular, other heart disease, or athletic conditioning.
complementary h. increase in size or expansion of part of an organ or tissue to fill the space left by the destruction of another portion of the same organ or tissue.
concentric h. thickening of the walls of the heart or any cavity with apparent diminution of the capacity of the cavity.
eccentric h. thickening of the wall of the heart or other cavity, with dilation.
endemic h. enlargement of the calcaneus preceded by fever and pain in the heel, reported from the Gold Coast (now Ghana) and in Taiwan among the indigenous population.
false h. SYN: pseudohypertrophy.
functional h. SYN: physiologic h..
giant h. of gastric mucosa SYN: Ménétrier disease.
hemangiectatic h. SYN: Klippel-Trenaunay-Weber syndrome.
lipomatous h. SYN: lipomatous infiltration.
numerical h. SYN: hyperplasia.
physiologic h. temporary increase in size of an organ or part to provide for a natural increase of function, such as the kind that occurs in the walls of the uterus and in the mammae during pregnancy. SYN: functional h..
quantitative h. SYN: hyperplasia.
simple h. increase in size of cells.
simulated h. increased size of a part due to continued growth unrestrained by attritions, as is seen in the case of the teeth of certain animals when the opposing teeth have been destroyed.
true h. an increase in size involving all the different tissues composing the part.
vicarious h. h. of an organ following failure of another organ because of a functional relationship between them; e.g., enlargement of the pituitary gland, after destruction of the thyroid.

hypertropia
hypertropia (hi′per-tro′pe-a)

An ocular deviation with one eye higher than the other. [hyper- + G. trope, a turn]

hypertyrosinemia
hypertyrosinemia (hi′per-ti′ro-si-ne′me-a)

SYN: tyrosinemia.

hyperuracil thyminuria
hyperuracil thyminuria (hi′per-oor′a-sil)

An inherited disorder in which there are elevated levels of uracil and thymine in the urine; associated with a deficiency of dihydropyrimidine dehydrogenase and resultant impaired CNS function.

hyperuricemia
hyperuricemia (hi′per-u-re-se′me-a)

Enhanced blood concentrations of uric acid.

hyperuricemic
hyperuricemic (hi′per-u-ri-se′mik)

Relating to or characterized by hyperuricemia.

hyperuricuria
hyperuricuria (hi′per-u-ri-ku′re-a)

Increased urinary excretion of uric acid.

hypervaccination
hypervaccination (hi′per-vak-si-na′shun)

Repeated inoculation of an individual already immunized; used as a means of preparing a highly potent antiserum.

hypervalinemia
hypervalinemia (hi′per-val-i-ne′me-a)

Abnormally high plasma concentrations of valine, a common finding in maple syrup urine disease.

hypervascular
hypervascular (hi′per-vas′ku-ler)

Abnormally vascular; containing an excessive number of blood vessels. [hyper- + L. vas, a vessel]

hyperventilation
hyperventilation (hi′per-ven-ti-la′shun)

Increased alveolar ventilation relative to metabolic carbon dioxide production, so that alveolar carbon dioxide pressure decreases to below normal. SYN: overventilation.

hypervitaminosis
hypervitaminosis (hi′per-vi′ta-mi-no′sis)

A condition resulting from the ingestion of an excessive amount of a vitamin preparation, symptoms varying according to the particular vitamin implicated; serious effects may be caused by overdosage with fat-soluble vitamins, especially A or D, and rarely with water-soluble vitamins.

hypervolemia
hypervolemia (hi′per-vo-le′me-a)

Abnormally increased volume of blood. SYN: plethora (1) , repletion. [hyper- + L. volumen, volume, + G. haima, blood]

hypervolemic
hypervolemic (hi′per-vo-le′mik)

Pertaining to or characterized by hypervolemia.

hypervolia
hypervolia (hi-per-vo′le-a)

Augmented water content or volume of a given compartment; e.g., cellular h..

hypesthesia
hypesthesia (hi-pes-the′ze-a)

Diminished sensitivity to stimulation. SYN: hypoesthesia. [G. hypo, under, + aisthesis, feeling]
olfactory h. SYN: hyposmia.

hypha
hypha, pl .hyphae (hi′fa, hi′fe)

A branching tubular cell characteristic of the filamentous fungi (molds). In most species the hyphae are divided by cross-walls (septa) into multicellular hyphae; intercommunicating hyphae constitute a mycelium, the visible colony on natural substrates or artificial laboratory media. The terms h. and mycelium often are used interchangeably. [G. hyphe, a web]
racquet h. a vegetative h. with distal ends of successive cells inflated, resembling a string of elongated snowshoes or tennis racquets; seen in many mycelial fungi, e.g., many dermatophyte species in culture.
spiral hyphae hyphae that end in a flat or helical coil, as in laboratory colonies of Trichophyton mentagrophytes.

hyphedonia
hyphedonia (hip-he-do′ne-a)

A habitually lessened or attenuated degree of pleasure from that which should normally give great pleasure. [G. hypo, under, + hedone, pleasure]

hyphema
hyphema (hi-fe′ma)

Blood in the anterior chamber of the eye. [G. hyphaimos, suffused with blood]

hyphemia
hyphemia (hi-fe′me-a)

SYN: hypovolemia. [hypo- + G. haima, blood]
intertropical h., tropical h. SYN: ancylostomiasis.

Hyphomyces destruens
Hyphomyces destruens (hi-fo-mi′ses des′troo-enz)

Older name for Pythium insidiosum.

Hyphomycetes
Hyphomycetes (hi′fo-mi-se′tes)

A class of fungi that includes all of the filamentous members of the Fungi Imperfecti that form neither acervuli nor pycnidia. No sexual reproduction occurs; most members of this group produce asexual spores. [G. hyphe, web, + mykes, fungus]

hyphomycosis
hyphomycosis (hi′fo-mi-ko′sis)

A disease of horses and mules (rarely of humans) caused by the fungus Pythium insidiosum (Hyphomyces destruens), characterized by granulomatous and necrotic lesions that appear on the head and lower legs, ulcerate, and enlarge by subcutaneous extension.

hypn- hypn-

See hypno-.

hypnagogic
hypnagogic (hip-na-goj′ik)

Denoting a transitional state, related to the hypnoidal, preceding sleep; applied also to various hallucinations that may manifest themselves at that time. See hypnoidal. [hypno- + G. agogos, leading]

hypno- hypno-, hypn-

Sleep, hypnosis. [G. hypnos,]

hypnoanalysis
hypnoanalysis (hip′no-a-nal′i-sis)

Psychoanalysis or other psychotherapy which employs hypnosis as an adjunctive technique.

hypnoanalytic
hypnoanalytic (hip′no-an-a-lit′ik)

Pertaining to hypnoanalysis.

hypnocatharsis
hypnocatharsis (hip′no-ka-thar′sis)

Ventilation of suppressed or repressed emotional tension, conflicts, and anxiety under hypnosis. [hypno- + G. katharsis, purification]

hypnocyst
hypnocyst (hip′no-sist)

A quiescent or “sleeping” cyst; an encysted protozoon, the reproductive activity of which is in abeyance. [hypno- + G. kystis, bladder (cyst)]

hypnogenesis
hypnogenesis (hip-no-jen′e-sis)

The induction of sleep or of the hypnotic state. [hypno- + G. genesis, production]

hypnogenic
hypnogenic, hypnogenous (hip-no-jen′ik, -noj′e-nus)

1. Relating to hypnogenesis. 2. An agent capable of inducing a hypnotic state. See hypnosis.

hypnoid
hypnoid

SYN: hypnoidal.

hypnoidal
hypnoidal (hip-noy′dal)

Resembling hypnosis; denoting the subwaking state, a mental condition intermediate between sleeping and waking. See hypnagogic. SYN: hypnoid. [hypno- + G. eidos, resemblance]

hypnophobia
hypnophobia (hip-no-fo′be-a)

Morbid fear of falling asleep. [hypno- + G. phobos, fear]

hypnopompic
hypnopompic (hip-no-pom′pik)

Denoting the occurrence of visions or dreams during the drowsy state following sleep. [hypno- + G. pompe, procession]

hypnosis
hypnosis (hip-no′sis)

An artificially induced trancelike state, resembling somnambulism, in which the subject is highly susceptible to suggestion, oblivious to all else, and responds readily to the commands of the hypnotist; its scientific validity has been accepted and rejected through several cycles during the past two centuries. See mesmerism. SYN: hypnotic sleep, hypnotic state. [G. hypnos, sleep, + -osis, condition]
lethargic h. the deep sleep following major h.. SYN: trance coma.
major h. a state of extreme suggestibility in h. in which the subject is insensible to all outside impressions except the commands of the hypnotist.
minor h. an induced state resembling normal sleep in which the subject is susceptible to suggestion, though not to the extent of catalepsy or somnambulism.

hypnotherapy
hypnotherapy (hip-no-thar′a-pe)

1. Psychotherapeutic treatment by means of hypnotism. 2. Treatment of disease by inducing a trance-like sleep.

hypnotic
hypnotic (hip-not′ik)

1. Causing sleep. 2. An agent that promotes sleep. SYN: soporific (2) . 3. Relating to hypnotism. [G. hypnotikos, causing one to sleep]

hypnotism
hypnotism (hip′no-tizm)

1. The process or act of inducing hypnosis. SYN: somnolism. 2. The practice or study of hypnosis. See mesmerism. [G. hypnos, sleep]

hypnotist
hypnotist (hip′no-tist)

One who practices hypnotism.

hypnotize
hypnotize (hip′no-tiz)

To induct one into hypnosis.

hypnozoite
hypnozoite (hip-no-zo′it)

Exoerythrocytic schizozoite of Plasmodium vivax or P. ovale in the human liver, characterized by delayed primary development; thought to be responsible for malarial relapse.

hypo- hypo-

1. Prefix denoting deficient, below normal. SEE ALSO: hyp-. Cf.:sub-. 2. In chemistry, denoting the lowest, or least rich in oxygen, of a series of chemical compounds. [G. hypo, under]

hypoacidity
hypoacidity (hi′po-a-sid′i-te)

A lower than normal degree of acidity, as of the gastric juice.

hypoacusis
hypoacusis (hi′po-a-koo′sis)

SYN: hypacusis.

hypoadenia
hypoadenia (hi-po-a-de′ne-a)

Any deficiency in the function of a glandular organ or tissue. [hypo- + G. aden, gland]

hypoadrenalism
hypoadrenalism (hi′po-a-dre′nal-izm)

Reduced adrenocortical function.

hypoalbuminemia
hypoalbuminemia (hi′po-al-boo-mi-ne′me-a)

An abnormally low concentration of albumin in the blood. SYN: hypalbuminemia.

hypoaldosteronism
hypoaldosteronism (hi′po-al-dos′ter-on-izm)

A condition due to deficient secretion of aldosterone; can occur in two forms: 1) as part of generalized adrenocortical insufficiency; 2) as a selective deficiency caused by a primary defect of the adrenal gland or a defect in control of aldosterone secretion.
hyporeninemic h. selective aldosterone deficiency resulting from low renin production.
isolated h. SYN: selective h..
selective h. aldosterone deficiency without a concomitant deficiency of glucocorticoid hormones. SYN: isolated h..

hypoaldosteronuria
hypoaldosteronuria (hi′po-al-dos′ter-on-oo′re-a)

Abnormally low levels of aldosterone in the urine.

hypoalgesia
hypoalgesia (hi-po-al-je′ze-a)

SYN: hypalgesia. [hypo- + G. algesis, a sense of pain]

hypoalimentation
hypoalimentation (hi′po-al-i-men-ta′shun)

SYN: subalimentation.

hypoazoturia
hypoazoturia (hi′po-az-o-too′re-a)

Excretion of abnormally small quantities of nonprotein nitrogenous material (especially urea) in the urine. SYN: hypazoturia. [hypo- + Fr. azote, nitrogen, + G. ouron, urine]

hypobaria
hypobaria (hi-po-bar′e-a)

SYN: hypobarism.

hypobaric
hypobaric (hi-po-bar′ik)

1. Pertaining to pressure of ambient gases below 1 atmosphere. 2. With respect to solutions, less dense than the diluent or medium; e.g., in spinal anesthesia, a h. solution has a density lower than that of spinal fluid. [hypo- + G. baros, weight]

hypobarism
hypobarism (hi-po-bar′izm)

Dysbarism resulting from decreasing barometric pressure on the body without hypoxia; gas in body cavities tends to expand, and gases dissolved in body fluids tend to come out of solution as bubbles. Cf.:decompression sickness. SYN: hypobaria.

hypobaropathy
hypobaropathy (hi′po-ba-rop′a-the)

Sickness produced by reduced barometric pressure; not always distinguished from hypobarism and altitude sickness. [hypo- + G. baros, weight, + pathos, suffering]

hypobetalipoproteinemia
hypobetalipoproteinemia (hi′po-ba′ta-lip′o-pro′ten-e′me-a) [MIM*107730]

Abnormally low levels of β-lipoproteins in the plasma, occasionally with acanthocytosis and neurological signs; autosomal dominant inheritance; caused by mutation in the apolipoprotein B gene (APOB) on 2p. SEE ALSO: abetalipoproteinemia.
familial h. a disorder similar to abetalipoproteinemia; chylomicron formation still occurs, but LDL levels are typically low.
h. with apo B-37 a disorder in which LDL levels are very low, there is a mild fat malabsorption, and a truncated apolipoprotein B-37 is formed.

hypoblast
hypoblast (hi′po-blast)

Cell layer adjacent to the yolk sac cavity and subjacent to the epiblast of a bilayered embryo. [hypo- + G. blastos, germ]

hypoblastic
hypoblastic (hi-po-blas′tik)

Relating to or derived from the hypoblast.

hypobranchial
hypobranchial (hi-po-brang′ke-al)

Located beneath the branchial apparatus.

hypobromite
hypobromite (hi-po-bro′mit)

A salt of hypobromous acid.

hypobromous acid
hypobromous acid (hi-po-bro′mus)

An acid, HOBr, the aqueous solution of which possesses oxidizing and bleaching properties.

hypocalcemia
hypocalcemia (hi′po-kal-se′me-a)

Abnormally low levels of calcium in the circulating blood; commonly denotes subnormal concentrations of calcium ions.

hypocalcification
hypocalcification (hi′po-kal-si-fi-ka′shun)

Deficient calcification of bone or teeth.
enamel h. [MIM*104500] a defect of enamel maturation, characterized by soft opaque or yellowish white lusterless enamel. A variety of amelogenesis imperfecta. Autosomal dominant, autosomal recessive, and X-linked recessive forms exist.

hypocapnia
hypocapnia (hi-po-kap′ne-a)

Abnormally decreased arterial carbon dioxide tension. SYN: hypocarbia. [hypo- + G. kapnos, smoke, vapor]

hypocarbia
hypocarbia (hi-po-kar′be-a)

SYN: hypocapnia.

hypocelom
hypocelom (hi-po-se′lom)

Rarely used term for the ventral portion of the celom, or body cavity, of the embryo. [hypo- + G. koilos, hollow]

hypochloremia
hypochloremia (hi′po-klo-re′me-a)

An abnormally low level of chloride ions in the circulating blood.

hypochloremic
hypochloremic (hi′po-klo-re′mik)

Pertaining to or characterized by hypochloremia.

hypochlorhydria
hypochlorhydria (hi′po-klor-hi′dre-a, -hid′ri-ah)

Presence of an abnormally small amount of hydrochloric acid in the stomach. SYN: hypohydrochloria.

hypochlorite
hypochlorite (hi-po-klor′it)

A salt of hypochlorous acid.

hypochlorous acid
hypochlorous acid (hi-po-klor′us)

An acid, HOCl, having oxidizing and bleaching properties.

hypochloruria
hypochloruria (hi′po-klor-u′re-a)

Excretion of abnormally small quantities of chloride ions in the urine.

hypocholesteremia
hypocholesteremia (hi′po-ko-les-te-re′me-a)

SYN: hypocholesterolemia.

hypocholesterinemia
hypocholesterinemia (hi′po-ko-les′te-ri-ne′me-a)

SYN: hypocholesterolemia.

hypocholesterolemia
hypocholesterolemia (hi′po-ko-les′ter-ol-e′me-a)

The presence of abnormally small amounts of cholesterol in the circulating blood. SYN: hypocholesteremia, hypocholesterinemia.

hypocholia
hypocholia (hi-po-ko′le-a)

Rarely used term for oligocholia.

hypochondria
hypochondria (hi-po-kon′dre-a)

SYN: hypochondriasis.

hypochondriac
hypochondriac (hi-po-kon′dre-ak)

1. A person with a somatic overconcern, including morbid attention to the details of bodily functioning and exaggeration of any symptoms no matter how insignificant. 2. A person manifesting hypochondriasis. 3. Beneath the ribs; relating to the hypochondrium.

hypochondriacal
hypochondriacal (hi′po-kon-dri′a-kal)

Relating to or suffering from hypochondriasis.

hypochondriasis
hypochondriasis (hi′po-kon-dri′a-sis)

A morbid concern about one's own health and exaggerated attention to any unusual bodily or mental sensations; a delusion that one is suffering from some disease for which no physical basis is evident. SYN: hypochondria, hypochondriacal neurosis. [fr. hypochondrium, regarded as the site of hypochondria, + G. -iasis, condition]

hypochondrium
hypochondrium, pl .hypochondria (hi-po-kon′dre-um, -a) [TA]

SYN: hypochondriac region. [L. fr. G. hypochondrion, abdomen, belly, from hypo, under, + chondros, cartilage (of ribs)]

hypochondroplasia
hypochondroplasia (hi′po-kon-dro-pla′ze-a) [MIM*146000]

A skeletal dysplasia characterized by dwarfism with features similar to but much milder than achondroplasia; the skull and facies are normal; features not clinically evident until mid-childhood. Autosomal dominant inheritance, caused in some cases by mutation in the fibroblast growth factor receptor 3 (FGFR3) gene on chromosome 4p. [hypo- + G. chondros, cartilage, + plasis, a molding]

hypochordal
hypochordal (hi-po-kor′dal)

On the ventral side of the spinal cord. [hypo- + G. chorde, cord]

hypochromasia
hypochromasia (hi′po-kro-ma′ze-a)

SYN: hypochromia.

hypochromatic
hypochromatic (hi′-po-kro-mat′ik)

Containing a small amount of pigment, or less than the normal amount for the individual tissue. SYN: hypochromic (1) . [hypo- + G. chroma, color]

hypochromatism
hypochromatism (hi-po-kro′ma-tizm)

1. The condition of being hypochromatic. 2. SYN: hypochromia.

hypochromia
hypochromia (hi-po-kro′me-a)

An anemic condition in which the percentage of hemoglobin in the red blood cells is less than the normal range. SYN: hypochromasia, hypochromatism (2) , hypochrosis. [hypo- + G. chroma, color]

hypochromic
hypochromic (hi-po-kro′mik)

1. SYN: hypochromatic. 2. Denoting decrease in light absorption with a shift in wavelength to a lower wavelength.

hypochrosis
hypochrosis (hi-po-kro′sis)

SYN: hypochromia. [hypo- + G. chrosis, a tinting]

hypochylia
hypochylia (hi-po-ki′le-a)

Rarely used term for oligochylia. [hypo- + G. chylos, juice]

hypocinesis
hypocinesis, hypocinesia (hi′po-si-ne′sis, -ne′ze-a)

SYN: hypokinesis.

hypocitraturia
hypocitraturia (hi′po-si-tra-toor′e-a)

Abnormally low concentration of citrate in the urine.

hypocomplementemia
hypocomplementemia (hi′po-kom′ple-men-te′me-a)

A condition in which one or another component of complement is lacking or reduced in amount; associated with immune complex diseases and cases of membranoproliferative glomerulonephritis in which nephritic factor is present. Various autosomal forms are known, domimant [MIM*120550 and MIM*120980] and recessive [MIM*216950 and MIM*217070].

hypocone
hypocone (hi′po-kon)

The distolingual cusp of an upper molar tooth. [hypo- + G. konos, pine cone]

hypoconid
hypoconid (hi-po-kon′id)

The distobuccal cusp of a lower molar tooth.

hypoconule
hypoconule (hi-po-kon′ul)

The distal, or fifth, cusp of an upper molar tooth. [hypo- + Mod. L. dim. of L. conus, cone]

hypoconulid
hypoconulid (hi-po-kon′u-lid)

The distal, or fifth, cusp of a lower molar tooth. [hypo- + Mod. L. dim. of L. conus, cone]

hypocorticoidism
hypocorticoidism (hi-po-kor′ti-koyd-izm)

SYN: adrenocortical insufficiency.

hypocupremia
hypocupremia (hi′po-koo-pre′me-a)

Reduced copper content of the blood; found in Wilson disease because ceruloplasmin is depressed, even though serum albumin-attached copper is increased. [hypo- + L. cuprum, copper, + G. haima, blood]

hypocycloidal
hypocycloidal (hi′-po-si-kloy′dal)

A tricyclic motion used by mechanical tomography units to optimize blurring and reduce artifacts. [hypo- + G. kuklos, circle, + -oeides, appearance]

hypocystotomy
hypocystotomy (hi′po-sis-tot′o-me)

Perineal cystotomy.

hypocythemia
hypocythemia (hi′po-si-the′me-a)

Hypocytosis of the circulating blood, such as that observed in aplastic anemia. [hypo- + G. kytos, cell, + haima, blood]

hypocytosis
hypocytosis (hi′po-si-to′sis)

Varying degrees of abnormally low numbers of red and white cells and other formed elements of the blood; in some instances, the term is also used to indicate a paucity of component cells of any tissue. SEE ALSO: cytopenia, pancytopenia. [hypo- + G. kytos, cell, + -osis, condition]

hypodactyly
hypodactyly, hypodactylia, hypodactylism (hi′po-dak′ti-le, -dak-til′e-a, -dak′til-izm)

Less than the full normal complement of digits. [hypo- + G. daktylos, finger]

hypoderm
hypoderm (hi′po-derm)

SYN: subcutaneous tissue. [hypo- + G. derma, skin]

Hypoderma
Hypoderma (hi-po-der′ma)

A genus of botflies whose larvae are the cause of a tropical form of myiasis linearis (cutaneous larva migrans) of man; occasionally they invade the interior of the eye. Two species, H. bovis and H. lineatum, are botflies of cattle. The ova of H. bovis are deposited on hairs of the legs, and the larvae penetrate the skin and migrate through the tissues to the skin of the back, where they appear during late winter as the common warbles; these ulcerate to the surface and mature larvae escape in early summer, fall to the ground, pupate, and give rise to a new generation of flies. [hypo- + G. derma, skin]

hypodermatoclysis
hypodermatoclysis (hi′po-der-ma-tok′li-sis)

Rarely used spelling of hypodermoclysis.

hypodermatomy
hypodermatomy (hi′po-der-mat′o-me)

Subcutaneous division of a structure. [hypo- + G. derma, skin, + tome, incision]

hypodermatosis
hypodermatosis (hi′po-der-ma-to′sis)

Infection of herbivores and humans with larvae of flies of the genus Hypoderma.

hypodermic
hypodermic (hi′po-der′mik)

1. SYN: subcutaneous. 2. SYN: h. injection. 3. SYN: h. syringe.

hypodermis
hypodermis (hi-po-der′mis)

subcutaneous tissue.

hypodermoclysis
hypodermoclysis (hi′po-der-mok′li-sis)

Subcutaneous injection of a saline or other solution. [hypo- + G. derma, skin, + klysis, a washing out]

hypodiploid
hypodiploid (hi′-po-dip′loid)

Having a chromosome number less than the diploid number.

hypodipsia
hypodipsia (hi-po-dip′se-a)

A physiologic condition, perhaps caused by hypertonicity of body fluids, insufficient to initiate drinking but at times sufficient to sustain drinking when started; loosely, oligodipsia. SYN: insensible thirst, subliminal thirst. [hypo- + G. dipsa, thirst]

hypodontia
hypodontia (hi-po-don′she-a)

A condition of having fewer than the normal complement of teeth, either congenital or acquired. SYN: oligodontia, partial anodontia. [hypo- + G. odous, tooth]

hypodynamia
hypodynamia (hi′po-di-na′me-a, -di-nam′e-a)

Diminished power. [hypo- + G. dynamis, force]
h. cordis diminished force of cardiac contraction.

hypodynamic
hypodynamic (hi′po-di-nam′ik)

Possessing or exhibiting subnormal power or force.

hypoeccrisis
hypoeccrisis (hi′po-ek′ri-sis)

Reduced excretion of waste matter. [hypo- + G. eccrisis, separation]

hypoeccritic
hypoeccritic (hi′po-e-krit′ik)

Characterized by hypoeccrisis.

hypoechoic
hypoechoic (hi′po-e-ko′ik)

A region in an ultrasound image in which the echoes are weaker or fewer than normal or in the surrounding regions. [hypo- + echo + -ic]

hypoeosinophilia
hypoeosinophilia (hi′po-e′o-sin-o-fil′e-a)

SYN: eosinopenia.

hypoesophoria
hypoesophoria (hi′po-es-o-fo′re-a)

A tendency of the visual axis of one eye to deviate downward and inward, prevented by binocular vision. [hypo- + G. eso, within, + phoros, bearing]

hypoesthesia
hypoesthesia (hi′po-es-the′ze-a)

SYN: hypesthesia.

hypoexophoria
hypoexophoria (hi′po-ek-so-fo′re-a)

A tendency of the visual axis of one eye to deviate downward and outward, prevented by binocular vision. [hypo- + G. exo, without, + phoros, bearing]

hypoferremia
hypoferremia (hi′po-fer-e′me-a)

A deficiency of iron in the circulating blood.

hypofibrinogenemia
hypofibrinogenemia (hi′po-fi-brin′o-je-ne′me-a)

Abnormally low concentration of fibrinogen in the circulating blood plasma.

hypofrontality
hypofrontality (hi′po-fron-tal′i-te)

A decrease in the neuronal activity of various areas of the frontal lobes, arising from various etiologies and associated with a number of clinical symptoms or disorders.

hypofunction
hypofunction (hi′po-funk-shun)

Reduced, low, or inadequate function.

hypogalactia
hypogalactia (hi′po-ga-lak′she-a)

Less than normal milk secretion. [hypo- + G. gala, milk]

hypogalactous
hypogalactous (hi′po-ga-lak′tus)

Producing or secreting a less than normal amount of milk.

hypogammaglobinemia
hypogammaglobinemia (hi′po-gam′a-glo′bi-ne′me-a)

SYN: hypogammaglobulinemia.

hypogammaglobulinemia
hypogammaglobulinemia (hi′po-gam′a-glob′u-li-ne′me-a)

Decreased quantity of the gamma fraction of serum globulin; sometimes used loosely to denote decreased quantity of immunoglobulins in general; associated with increased susceptibility to pyogenic infections. SYN: hypogammaglobinemia.
acquired h. SYN: common variable immunodeficiency.
primary h. h. due to a primary immunodeficiency of immunoglobulin-forming cells (B-lymphocytes).
secondary h. SYN: secondary immunodeficiency.
transient h. of infancy a type of primary immunodeficiency that occurs in infants of both sexes, usually before the sixth month of life, probably resulting from immaturity of lymphoid tissue. SYN: transient agammaglobulinemia.
X-linked h., X-linked infantile h. a congenital, primary immunodeficiency characterized by decreased numbers (or absence) of circulating B lymphocytes with corresponding decrease in immunoglobulins of the five classes; associated with marked susceptibility to infection by pyogenic bacteria (notably, pneumococci and Haemophilus influenzae) beginning after loss of maternal antibodies; X-linked recessive inheritance caused by mutation in the Bruton tyrosine kinase gene (BTK) on Xq.
X-linked h. with growth hormone deficiency h. combined with a reduced number of B cells; characterized by short stature, delayed puberty, and recurrent infections.

hypoganglionosis
hypoganglionosis (hi′po-gang-le-on-o′sis)

A reduction in the number of ganglionic nerve cells.

hypogastric
hypogastric (hi-po-gas′trik)

Relating to the hypogastrium.

hypogastrium
hypogastrium (hi′po-gas′tre-um) [TA]

SYN: pubic region, pubic region. [G. hypogastrion, lower belly, fr. hypo, under, + gaster, belly]

hypogastrocele
hypogastrocele (hi′po-gas′tro-sel)

Hernia of the lower part of the abdomen. [hypogastrium + G. kele, hernia]

hypogastropagus
hypogastropagus (hi′po-gas-trop′a-gus)

Twins joined at the hypogastrium. See conjoined twins, under twin. [hypogastrium + G. pagos, fr. pegnynai, to fasten]

hypogastroschisis
hypogastroschisis (hi′po-gas-tros′ki-sis)

Congenital fissure of the abdominal wall in the hypogastric region. [hypogastrium + G. schisis, cleaving]

hypogenesis
hypogenesis (hi′po-jen′e-sis)

Congenital defect of growth with underdevelopment of parts or organs of the body. [hypo- + G. genesis, origin]
polar h. a less than normal degree of development at the cephalic or caudal extremity of the embryo.

hypogenetic
hypogenetic (hi′po-je-net′ik)

Relating to hypogenesis.

hypogenitalism
hypogenitalism (hi-po-jen′i-tal-izm)

Partial or complete failure of maturation of the genitalia; commonly, a consequence of hypogonadism.

hypogeusia
hypogeusia (hi-po-gu′se-a)

Diminished sense of taste. It may be: 1) general to all tastants, partial to some tastants, or specific to one or more tastants; 2) due to transport disorders (in access to the interior of the taste bud) or to sensorineural disorders (affecting the gustatory sensory cells or nerves or the central gustatory neural pathways); and 3) hereditary or acquired. [hypo- + G. geusis, taste]

hypoglobulia
hypoglobulia (hi′po-glo-bu′le-a)

Obsolete term for abnormally low numbers of red blood cells in the circulating blood; also used infrequently with reference to abnormally decreased proportions of erythroid elements in the bone marrow. [hypo- + G. globulus, globule]

hypoglossal
hypoglossal (hi-po-glos′al)

1. Below the tongue. 2. Relating to the twelfth cranial nerve, nervus hypoglossus. SYN: hypoglossus. [L. hypoglossus fr. hypo- + glossus, tongue]

hypoglossis
hypoglossis (hi-po-glos′is)

SYN: hypoglottis.

hypoglossus
hypoglossus (hi′po-glos′us)

SYN: hypoglossal, hypoglossal. [L.]

hypoglottis
hypoglottis (hi′po-glot′is)

The undersurface of the tongue. SYN: hypoglossis. [G. hypoglossis, or -glottis, undersurface of tongue, fr. hypo, under, + glossa, tongue]

hypoglycemia
hypoglycemia (hi′po-gli-se′me-a)

1. Symptoms resulting from low blood glucose (normal glucose range 60–100 mg/dL (3.3 to 5.6 mmol/L)) which are either autonomic or neuroglycopenic. Autonomic symptoms include sweating, trembling, feelings of warmth, anxiety, and nausea. Neuroglycopenic symptoms include feelings of dizziness, confusion, tiredness, difficulty speaking, headache and inability to concentrate. 2. Organic disease more often leads to neuroglycopenic symptoms, functional disorders to autonomic symptoms. Functional h. is of doubtful existence; the so-called post-prandial hypoglycemic syndrome has not been confirmed by blood sugar measurements. No convincing evidence has been found of the existence of early-diabetes h., or alimentary h.. SYN: glucopenia.
fasting h. excessively low blood glucose in association with fasting; can be seen in patients with hyperinsulinism but also occurs without definable disease.
ketotic h. the most common form of childhood h. after the neonatal period; it usually presents between the ages of 18 months and 5 years, and resolves spontaneously by late childhood; manifested by hypoglycemic episodes usually occurring during minor illnesses that cause decreased appetite; probably due to a defect in gluconeogenesis and limited glycogen stores.
leucine h. reduction in blood glucose concentration produced by administration of leucine; believed to reflect the ability of this amino acid to stimulate insulin secretion.
leucine-induced h. rare cause of h. occurring following ingestion of leucine. Seen especially in infants. SYN: leucine-sensitive h..
leucine-sensitive h. SYN: leucine-induced h..
mixed h. h. due to more than one cause.
neonatal h. [MIM*240900] familial onset of symptomatic h. during infancy, with persistently low blood glucose; a variant form [MIM*240800] is leucine-induced with hyperinsulinism and variable mental retardation.

hypoglycemic
hypoglycemic (hi′po-gli-se′mik)

Pertaining to or characterized by hypoglycemia.

hypoglycogenolysis
hypoglycogenolysis (hi′po-gli′ko-je-nol′i-sis)

Deficient glycogenolysis.

hypoglycorrhachia
hypoglycorrhachia (hi′po-gli-ko-rak′e-a)

Depressed concentration of glucose in the cerebrospinal fluid; a characteristic of bacterial, fungal, and tuberculous meningitis. [hypo- + G. glykys, sweet, + rhachis, spine]

hypognathous
hypognathous (hi′po-nath′us, hi-pog′na-thus)

Having a congenitally defectively developed small lower jaw. [hypo- + G. gnathos, jaw]

hypognathus
hypognathus (hi′po-nath′us, hi-pog′na-thus)

Unequal conjoined twins in which the rudimentary parasite is attached to the mandible of the autosite. See conjoined twins, under twin. [hypo- + G. gnathos, jaw]

hypogonadism
hypogonadism (hi′po-go′nad-izm)

Inadequate gonadal function, as manifested by deficiencies in gametogenesis and/or the secretion of gonadal hormones; results in atrophy or deficient development of secondary sexual characteristics and, when occurring in prepubertal males, in altered body habitus characterized by a short trunk and long limbs.
familial hypogonadotropic h. [MIM*312100 & MIM*307300] a group of disorders characterized by failure of sexual development, owing to inadequate secretion of pituitary gonadotropins; perhaps X-linked, but probably autosomal dominant and recessive modes of inheritance also exist.
hypergonadotropic h. defective gonadal development or function of the gonads, resulting from elevated levels of gonadotropins.
hypogonadotropic h. defective gonadal development or function, or both, resulting from inadequate secretion of pituitary gonadotropins. SYN: hypogonadotropic eunuchoidism, secondary h..
male h. SYN: eunuchoidism.
primary h. defective gonadal development or function, or both, due to abnormality or loss of the gonad itself.
secondary h. SYN: hypogonadotropic h..
h. with anosmia failure of sexual development secondary to inadequate secretion of pituitary gonadotrophins, associated with anosmia due to agenesis of the olfactory lobes of the brain. Autosomal dominant [MIM*147950], autosomal recessive [MIM*244200], and X-linked recessive [MIM*308700] forms exist; the X-linked form is caused by mutation in the Kallmann gene (KAL1) on Xp. SYN: Kallmann syndrome.

hypogonadotropic
hypogonadotropic (hi′po-gon′a-do-trop′ik)

Indicating inadequate secretion of gonadotropins and its consequences.

hypogranulocytosis
hypogranulocytosis (hi′po-gran′u-lo-si-to′sis)

SYN: granulocytopenia.

hypohepatia
hypohepatia (hi′po-he-pat′e-a)

Rarely used term for underfunctioning of the liver. [hypo- + G. hepar, liver]

hypohidrosis
hypohidrosis (hi′po-hi-dro′sis)

Diminished perspiration.

hypohydremia
hypohydremia (hi′po-hi-dre′me-a)

Any deficiency in the amount of fluid in the blood. [hypo- + G. hydor, water, + haima, blood]

hypohydrochloria
hypohydrochloria (hi′po-hi-dro-klor′e-a)

SYN: hypochlorhydria.

hypoisotonic
hypoisotonic (hi′po-i-so-ton′ik)

SYN: hypotonic.

hypokalemia
hypokalemia (hi′po-ka-le′me-a)

The presence of an abnormally small concentration of potassium ions in the circulating blood; occurs in familial periodic paralysis and in potassium depletion due to excessive loss from the gastrointestinal tract or kidneys. The changes of h. may include vacuolation of renal tubular epithelial cytoplasm with impairment of urinary concentrating power and acidification, flattening of the T wave of the electrocardiogram, and muscle weakness. SYN: hypopotassemia. [hypo- + Mod. L. kalium, potassium, + G. haima, blood]

hypokinemia
hypokinemia (hi′po-ki-ne′me-a)

Reduced circulation rate; reduced volume flow through the circulation; subnormal cardiac output. [hypo- + G. kineo, to move, + haima, blood]

hypokinesis
hypokinesis, hypokinesia (hi′po-ki-ne′sis, -ne′ze-a)

Diminished or slow movement. SYN: hypocinesis, hypocinesia, hypomotility. [hypo- + G. kinesis, movement]

hypokinetic
hypokinetic (hi′po-ki-net′ik)

Relating to or characterized by hypokinesis.

hypoleukemia
hypoleukemia (hi′po-loo-ke′me-a)

SYN: subleukemic leukemia.

hypoleydigism
hypoleydigism (hi-po-li′dig-izm)

Subnormal secretion of androgens by the interstitial (Leydig) cells of the testes.

hypolipoproteinemia
hypolipoproteinemia (hi′po-lip′o-pro-ten-e-me-a)

Decreased levels of a lipoprotein in the serum.

hypoliposis
hypoliposis (hi′po-li-po′sis)

Presence of an abnormally small amount of fat in the tissues.

hypologia
hypologia (hi′po-lo′je-a)

Lack of ability for speech. [hypo- + G. logos, word]

hypolymphemia
hypolymphemia (hi′po-lim-fe′me-a)

Abnormally small numbers of lymphocytes in the circulating blood.

hypomagnesemia
hypomagnesemia (hi′po-mag-ne-se′me-a)

Subnormal blood serum concentration of magnesium; may cause convulsions and concurrent hypocalcemia.

hypomania
hypomania (hi′po-ma′ne-a)

A mild degree of mania.

hypomastia
hypomastia (hi′po-mas′te-a)

Atrophy or congenital smallness of the breasts. [hypo- + G. mastos, breast]

hypomelancholia
hypomelancholia (hi′po-mel-an-ko′le-a)

A mild degree of mental depression.

hypomelanosis
hypomelanosis (hi′po-mel-a-no′sis)

SYN: leukoderma.
h. of Ito [MIM*146150 and MIM*308300] not a specific entity but rather represents features of many different forms of mosaicism; characterized by unilateral or bilateral hypopigmented macules in whorls, streaks, and patches in a “marble-cake” pattern, variably associated with epidermal nevi, alopecia, and ocular, skeletal, and neural abnormalities. SEE ALSO: incontinentia pigmenti. SYN: incontinentia pigmenti achromians.

hypomelia
hypomelia (hi-po-me′le-a)

General term for hypoplasia of some or all parts of one or more limbs. [hypo- + G. melos, limb]

hypomenorrhea
hypomenorrhea (hi′po-men-o-re′a)

Diminution of the flow or a shortening of the duration of menstruation. [hypo- + G. men, month, + rhoia, flow]

hypomere
hypomere (hi′po-mer)

1. The portion of the myotome that extends ventrolaterally to form body-wall and limb muscle, innervated by the primary ventral ramus of a spinal nerve. See hypaxial. 2. Less commonly, the somatic and splanchnic layers of the lateral mesoderm which give rise to the lining of the celom. [hypo- + G. meros, part]

hypometabolism
hypometabolism (hi′po-me-tab′o-lizm)

Reduced metabolism. SEE ALSO: hypometabolic state.
euthyroid h. an unusual condition resembling myxedema but with an apparently normal thyroid gland.

hypometria
hypometria (hi-po-me′tre-a)

Ataxia characterized by underreaching an object or goal; seen with cerebellar disease. Cf.:hypermetria. [hypo- + G. metron, measure]

hypomnesia
hypomnesia (hi-po-ne′ze-a)

Impaired memory. Cf.:hypermnesia. [hypo- + G. mneme, memory]

hypomorph
hypomorph (hi′po-morf)

1. A person whose standing height is short in proportion to the sitting height, owing to shortness of the limbs. Cf.:hypermorph, endomorph. 2. A mutant gene that causes a partial decrease in the activity controlled by the gene. Cf.:hypermorph. [hypo- + G. morphe, form]

hypomotility
hypomotility (hi′po-mo-til′i-te)

SYN: hypokinesis.

hypomyelination
hypomyelination, hypomyelinogenesis (hi′po-mi′e-lin-a-shun, -o-jen′e-sis)

Defective formation of myelin in the spinal cord and brain; the basis for a number of demyelinating diseases.

hypomyotonia
hypomyotonia (hi′po-mi-o-to′ne-a)

A condition of diminished muscular tonus. [hypo- + G. mys (myo-) muscle, + tonos, tension]

hypomyxia
hypomyxia (hi′po-mik′se-a)

A condition in which the secretion of mucus is diminished. [hypo- + G. myxa, mucus]

hyponatremia
hyponatremia (hi′po-na-tre′me-a)

Abnormally low concentrations of sodium ions in the circulating blood. [hypo- + natrium, + G. haima, blood]
depletional h. decreased serum sodium concentration associated with loss of sodium from the circulating blood via the GI tract, kidney, skin, or into “third space.” Accompanied by hypovolemic and hypotonic state.

hyponeocytosis
hyponeocytosis (hi′po-ne′o-si-to′sis)

Leukopenia associated with the presence of immature and young leukocytes (especially in the granulocytic series), i.e., a “shift to the left” in the hemogram. SYN: hyposkeocytosis. [hypo- + G. neos, new, + kytos, cell, + -osis, condition]

hyponoia
hyponoia (hi′po-noy′-a)

Deficient or sluggish mental activity or imagination. [hypo- + G. noeo, to think]

hyponychial
hyponychial (hi′po-nik′e-al)

1. SYN: subungual. 2. Relating to the hyponychium.

hyponychium
hyponychium (hi′po-nik′e-um) [TA]

The epithelium of the nail bed, particularly its proximal part in the region of the nailroot and lunula, forming the nail matrix. [hypo- + G. onyx, nail]

hyponychon
hyponychon (hi-pon′i-kon)

Subungual hemorrhage. [hypo- + G. onyx, nail]

hypooncotic
hypooncotic (hi′po-on-kot′ik)

Indicating an oncotic pressure less than normal, e.g., of blood plasma.

hypoorthocytosis
hypoorthocytosis (hi′po-or′tho-si-to′sis)

Leukopenia in which the relative numbers of the various types of white blood cells are within the normal range, and no immature cells are found in the circulating blood. [hypo- + G. orthos, correct, + kytos, cell, + -osis, condition]

hypoovarianism
hypoovarianism (hi′po-o-va′re-an-izm)

Inadequate ovarian function, commonly referring to reduced secretion of ovarian hormones. SYN: hypovarianism.

hypopancreatism
hypopancreatism (hi′po-pan′kre-a-tizm)

A condition of diminished activity of digestive enzyme secretion by the pancreas.

hypopancreorrhea
hypopancreorrhea (hi′po-pan′kre-o-re′a)

Reduced delivery of pancreatic digestive enzyme secretions. [hypo- + pancreas + G. rhoia, flow]

hypoparathyroidism
hypoparathyroidism (hi′po-par-a-thi′royd-izm)

A condition due to diminution or absence of the secretion of the parathyroid hormones, with low serum calcium and tetany, and sometimes with increased bone density. SEE ALSO: pseudohypoparathyroidism. SYN: parathyroid insufficiency.
familial h. inherited isolated h. characterized by hypocalcemia, hyperphosphatemia, cataracts, intracerebral calcifications, and tetany; all three mendelian forms (sex-linked, autosomal dominant and recessive) of inheritance are known [MIM*146200, MIM*241400, and MIM*307700]. The autosomal dominant form is caused by mutation in either the parathyroid hormone gene (PTH) on chromosome 11p or the calcium sensing receptor gene (CASR) on 3q.

hypopepsia
hypopepsia (hi-po-pep′se-a)

Impaired digestion, especially that due to a deficiency of pepsin. SYN: oligopepsia. [hypo- + G. pepsis, digestion]

hypoperistalsis
hypoperistalsis (hi′po-per-i-stal′sis)

Reduced or inadequate peristalsis.

hypophalangism
hypophalangism (hi′po-fa-lan′jizm)

Congenital absence of one or more of the phalanges of a finger or toe.

hypopharynx
hypopharynx (hi′po-far′inks)

laryngopharynx.

hypophonesis
hypophonesis (hi′po-fo-ne′sis)

In percussion or auscultation, a sound that is diminished or fainter than usual. [hypo- + G. phonesis, a sounding]

hypophonia
hypophonia (hi′po-fo′ne-a)

An abnormally weak voice due to incoordination of the muscles concerned in vocalization. SYN: leptophonia, microphonia, microphony. [hypo- + G. phone, voice]

hypophoria
hypophoria (hi′po-fo′re-a)

A tendency of the visual axis of one eye to deviate downward, prevented by binocular vision. [hypo- + G. phora, motion]

hypophosphatasemia
hypophosphatasemia (hi′po-fos′fa-ta-se′me-a)

SYN: hypophosphatasia.

hypophosphatasia
hypophosphatasia (hi′po-fos′fa-ta′ze-a)

An abnormally low content of alkaline phosphatase in the circulating blood. SYN: hypophosphatasemia.
adult h. an autosomal dominant trait with early loss of teeth, bowing, and beaten-copper skull; there is evidence that the basic defect is in liver alkaline phosphatase.
childhood h. a relatively mild autosomal recessive form of h.; it may be allelic with congenital h..
congenital h. [MIM*241500] a rare disorder associated with a low level of serum alkaline phosphatase, hyperphosphaturia, hypercalcemia, skeletal abnormalities, pathologic fractures, craniostenosis, premature loss of teeth, and often early death; eyes may show blue sclerae, lid retraction, band-shaped keratopathy, cataracts, papilledema, and optic atrophy; autosomal recessive inheritance, caused by mutation in the liver alkaline phosphatase gene (ALPL) on chromosome 1p.

hypophosphatemia
hypophosphatemia (hi′po-fos-fa-te′me-a)

Abnormally low concentrations of phosphates in the circulating blood. See also entries under rickets.

hypophosphaturia
hypophosphaturia (hi′po-fos′fa-too′re-a)

Reduced urinary excretion of phosphates.

hypophosphorous acid
hypophosphorous acid (hi-po-fos′fo-rus)

An aqueous solution containing 31% HPH₂O₂; used as a stabilizing reducing agent in pharmaceutical preparations.

hypophrasia
hypophrasia (hi′po-fra′ze-a)

Slowness or lack of speech associated with a psychosis or brain injury. [hypo- + G. phrasis, speaking]

hypophyseal
hypophyseal (hi′po-fiz′e-al)

SYN: hypophysial.

hypophysectomize
hypophysectomize (hi′pof-i-sek′to-miz)

To remove the pituitary gland.

hypophysectomy
hypophysectomy (hi′pof-i-sek′to-me)

Surgical removal of the hypophysis or pituitary gland.

hypophyseoprivic
hypophyseoprivic (hi′po-fiz′e-o-priv′ik)

SYN: hypophysioprivic.

hypophyseotropic
hypophyseotropic (hi′po-fiz′e-o-trop′ik)

SYN: hypophysiotropic.

hypophysial
hypophysial (hi′po-fiz′e-al)

Relating to a hypophysis. SYN: hypophyseal.

hypophysin
hypophysin (hi-pof′i-sin)

An aqueous extract of the posterior lobe of the fresh hypophysis of cattle; contains oxytocin and vasopressin.

hypophysioprivic
hypophysioprivic (hi′po-fiz′e-o-priv′ik)

Denoting the condition in which the pituitary gland may be functionally inactive or may be absent, as after hypophysectomy. SYN: hypophyseoprivic. [hypophysis + L. privus, deprived of]

hypophysiotropic
hypophysiotropic (hi′po-fiz′e-o-trop′ik)

Denoting a stimulatory hormone that acts on the pituitary gland (hypophysis). SYN: hypophyseotropic.

hypophysis
hypophysis (hi-pof′i-sis) [TA]

SYN: pituitary gland. SEE ALSO: hypothalamus. [G. an undergrowth]
h. cerebri SYN: pituitary gland.
pharyngeal h. residual tissue derived from the hypophysial diverticulum that lies in the lamina propria of the nasopharynx; its cells and their arrangement are identical with those of the pars distalis. SYN: pars pharyngea hypophyseos.
h. sicca SYN: posterior pituitary.

hypophysitis
hypophysitis (hi-pof-i-si′tis)

Inflammation of the hypophysis.
lymphocytic h. an acute anterior pituitary lymphocytic reaction characterized clinically by signs and symptoms of anterior pituitary insufficiency; probably an autoimmune disorder because antipituitary antibodies are present in the serum. SYN: lymphoid h..
lymphoid h. SYN: lymphocytic h..

hypopiesis
hypopiesis (hi′po-pi-e′sis)

SYN: hypotension (1) . [hypo- + G. piesis, pressure]
orthostatic h. SYN: orthostatic hypotension.

hypopigmentation
hypopigmentation (hi′po-pig-men-ta′shun)

Deficiency of cutaneous melanin relative to surrounding skin. See albinism. [hypo- + pigmentation]

hypopituitarism
hypopituitarism (hi′po-pi-too′i-ta-rizm)

A condition due to diminished activity of the anterior lobe of the hypophysis, with inadequate secretion, to varying degrees, of one or more anterior pituitary hormones.

hypoplasia
hypoplasia (hi′po-pla′ze-a)

1. Underdevelopment of a tissue or organ, usually due to a deficiency in the number of cells. 2. Atrophy due to destruction of some of the elements and not merely to their general reduction in size. [hypo- + G. plasis, a molding]
cartilage-hair h. [MIM*250250 & MIM*250460] a skeletal dysplasia prevalent among the Amish, characterized by short-limb dwarfism, sparse, light-colored hair, T-cell immunologic defect rendering them susceptible to infections, and radiographic findings of metaphyseal dysplasia. Autosomal recessive inheritance, the gene maps to 9p. SYN: McKusick metaphyseal dysplasia.
enamel h. a developmental disturbance of teeth characterized by deficient or defective enamel matrix formation; may be hereditary, as in amelogenesis imperfecta, or acquired, as encountered in dental fluorosis, local infection, childhood fevers, and congenital syphilis.
focal dermal h. [MIM*305600] inherited as an X-linked dominant with in utero lethality in males; characterized by linear areas of dermal atrophy or h., herniation of fat through the dermal defects, and papillomata of the mucus membranes or skin; may be associated with digital, ocular, and oral anomalies; mental retardation; and bony striations. SYN: Goltz syndrome.
optic nerve h. congenitally small optic disk resulting from a reduced number of retinal ganglion cells and, therefore, a reduced number of axons; visual impairment may be marked. See de Morsier syndrome.
renal h. an abnormally small kidney that is morphologically normal but has either a reduced number of nephrons or smaller nephrons.
h. of right ventricle failure of development of the right ventricle resulting in its having little muscle and much connective tissue instead of the reverse.
right ventricular h. SYN: parchment heart.
thymic h. SYN: DiGeorge syndrome.

hypoplastic
hypoplastic (hi′po-plas′tik)

Pertaining to or characterized by hypoplasia.

hypopnea
hypopnea (hi-pop′ne-a)

Breathing that is shallower, and/or slower, than normal. SYN: oligopnea. [hypo- + G. pnoe, breathing]

hypoposia
hypoposia (hi′po-po′se-a)

Hypodipsia, primarily due to reduced tendency to drink rather than the reduced sensation of thirst. [hypo- + G. posis, drinking]

hypopotassemia
hypopotassemia (hi′po-po-ta-se′me-a)

SYN: hypokalemia.

hypoproaccelerinemia
hypoproaccelerinemia (hi′po-pro-ak-sel′er-i-ne′me-a)

Abnormally low concentration of blood-clotting factor V, i.e., proaccelerin, in the circulating blood.

hypoproconvertinemia
hypoproconvertinemia (hi′po-pro-kon-ver′ti-ne′me-a)

Abnormally low concentration of blood-clotting factor VII, i.e., proconvertin, in the circulating blood; a deficiency causes a quantitative prolongation of the prothrombin time.

hypoproteinemia
hypoproteinemia (hi′po-pro′te-in-e′me-a, -pro-ten-)

Abnormally small amounts of total protein in the circulating blood plasma.

hypoproteinosis
hypoproteinosis (hi′po-pro′te-in-o′sis, -pro′ten-)

A condition, especially in children, due to a dietary deficiency of protein; characterized by anorexia, vomiting, retardation of growth, anemia, and increased susceptibility to infections.

hypoprothrombinemia
hypoprothrombinemia (hi′po-pro-throm′bin-e′me-a)

Abnormally small amounts of prothrombin in the circulating blood. SYN: prothrombinopenia.

hypoptyalism
hypoptyalism (hi′po-ti′a-lizm)

SYN: hyposalivation. [hypo- + G. ptyalon, saliva]

hypopyon
hypopyon (hi-po′pi-on)

The presence of leukocytes in the anterior chamber of the eye. [hypo- + G. pyon, pus]
recurrent h. SYN: Behçet syndrome.

hyporeflexia
hyporeflexia (hi′po-re-flek′se-a)

A condition in which the reflexes are weakened.

hyporeninemia
hyporeninemia (hi′po-ren-i-ne′me-a)

Low levels of renin in the circulating blood.

hyporeninemic
hyporeninemic (hi′po-ren-i-ne′mik)

Denoting or characterized by hyporeninemia.

hyporiboflavinosis
hyporiboflavinosis (hi′po-ri′bo-fla-vi-no′sis)

A more correct term than the more commonly used ariboflavinosis, q.v.

hyposalivation
hyposalivation (hi′po-sal′i-va′shun)

Reduced salivation. SYN: hypoptyalism.

hyposcheotomy
hyposcheotomy (hi-pos-ke-ot′o-me)

Incision or puncture into a hydrocele at its most dependent point. [hypo- + G. oscheon, scrotum, + tome, incision]

hyposcleral
hyposcleral (hi-po-skler′al)

Beneath the sclerotic coat of the eyeball.

hyposensitivity
hyposensitivity (hi′po-sen-si-tiv′i-te)

A condition of subnormal sensitivity, in which the response to a stimulus is unusually delayed or lessened in degree.

hyposensitization
hyposensitization

SYN: desensitization.

hyposkeocytosis
hyposkeocytosis (hi′po-ske′o-si-to′sis)

SYN: hyponeocytosis. [hypo- + skaios, left, + kytos, cell, + -osis, condition]

hyposmia
hyposmia (hi-poz′me-a)

Diminished sense of smell. It may be: 1) general to all odorants, partial to some odorants, or specific to one or more odorants; 2) due to transport disorders (in nasal obstruction) or to sensorineural disorders (affecting the olfactory neuroepithelium or the central olfactory neural pathways); and 3) hereditary or acquired. SYN: olfactory hypesthesia. [hypo- + G. osme, smell]

hyposmosis
hyposmosis (hi-pos-mo′sis)

A reduction in the rapidity of osmosis.

hyposmotic
hyposmotic (hi-pos-mot′ik)

Having an osmolality less than another fluid, ordinarily assumed to be plasma or extracellular fluid.

hyposomatotropism
hyposomatotropism (hi′po-so′ma-to-tro′pizm)

A state characterized by deficient secretion of pituitary growth hormone (somatotropin).

hyposomia
hyposomia (hi′po-so′me-a)

Inadequate development of the body. [hypo- + G. soma, body]

hyposomniac
hyposomniac (hi′po-som′ne-ak)

A person with a reduction in sleep time. [hypo- + L. somnus, sleep]

hypospadiac
hypospadiac (hi′po-spa′de-ak)

Relating to hypospadias.

hypospadias
hypospadias (hi′po-spa′de-as)

A developmental anomaly characterized by a defect on the ventral surface of the penis so that the urethral meatus is proximal to its normal glanular location; may be associated with chordee; also a similar defect in the female in which the urethra opens into the vagina. Cf.:epispadias. SYN: urogenital sinus anomaly. [hypo- + G. spao, to tear or gouge]
balanic h. SYN: glanular h..
coronal h. ventral and proximal malposition of meatus in the coronal sulcus.
glanular h. ventral and proximal glanular malposition of urethral meatus in a male. SYN: balanic h..
penile h. malposition of the urethral meatus on the ventral penile shaft.
penoscrotal h. malposition of the urethral opening at the junction of the penis and scrotum.
perineal h. h. in which the urethral meatus opens in the perineum near the anus; the scrotum is usually cleft.
scrotal h. h. with the urethral opening on the scrotal surface.
subcoronal h. malposition of the meatus in the coronal sulcus.

hyposphygmia
hyposphygmia (hi′po-sfig′me-a)

Abnormally low blood pressure with sluggishness of the circulation. [hypo- + G. sphyxis, pulse]

hyposplenism
hyposplenism (hi′po-splen′izm)

Absent or reduced splenic function, usually due to surgical removal, congenital aplasia, tumor replacement, or splenic vascular accident. Red cell abnormalities, including the presence of inclusions, nucleated erythrocytes, and target cells, are commonly present. Patients with h. are at increased risk of bacterial sepsis, especially due to pneumococcus.

hypostasis
hypostasis (hi-pos′ta-sis)

1. Formation of a sediment at the bottom of a liquid. 2. SYN: hypostatic congestion. 3. The phenomenon whereby the phenotype that would ordinarily be manifested at one locus is obscured by the genotype at another epistatic locus; e.g., in humans, the phenotype for the ABO blood group locus can be expressed only in the presence of its precursor, H substance. The Bombay factor in the homozygous state blocks H formation and obscures the ABO phenotype. [G. hypo-stasis, a standing under, sediment]
postmortem h. SYN: postmortem livedo.
pulmonary h. hydrostatic congestion of the lung.

hypostatic
hypostatic (hi-po-stat′ik)

1. Sedimentary;resulting from a dependent position. 2. Relating to hypostasis.

hyposthenuria
hyposthenuria (hi′pos-the-noo′re-a)

Excretion of urine of low specific gravity, due to inability of the tubules of the kidneys to produce a concentrated urine; also occurs following excessive water ingestion in diabetes insipidus. [hypo- + G. sthenos, strength, + ouron, urine]

hypostome
hypostome (hi′po-stom)

The central unpaired holdfast organ of the tick capitulum; the h. is covered with recurved spines that enable it to serve as an anchoring device while the tick feeds. [hypo- + G. stoma, mouth]

hypostomia
hypostomia (hi′po-sto′me-a)

A form of microstomia in which the oral opening is a small vertical slit. [hypo- + G. stoma, mouth]

hypostosis
hypostosis (hip-os-to′sis)

Deficient development of bone. [hypo- + G. osteon, bone, + -osis, condition]

hyposupradrenalism
hyposupradrenalism (hi′po-soo′pra-a-dre′nal-izm)

SYN: chronic adrenocortical insufficiency.

hyposystole
hyposystole (hi′po-sis′to-le)

A weak or incomplete cardiac systole.

hypotelorism
hypotelorism (hi-po-tel′or-izm)

Abnormal closeness of eyes. [hypo- + G. tele, far off, + horizo, to separate, fr. horos, boundary]

hypotension
hypotension (hi′po-ten′shun)

1. Subnormal arterial blood pressure. SYN: hypopiesis. 2. Reduced pressure or tension of any kind. [hypo- + L. tensio, a stretching]
arterial h. h. (1) .
idiopathic orthostatic h. the tendency for blood pressure to drop for unknown reasons on assuming upright posture.
induced h., controlled h. deliberate acute reduction of arterial blood pressure to reduce operative blood loss by pharmacologic means during anesthesia and surgery.
intracranial h. subnormal pressure of cerebrospinal fluid; most commonly following lumbar puncture and associated with headache, nausea, vomiting, stiffness of the neck, and sometimes fever; may also result from dehydration.
orthostatic h. a form of low blood pressure that occurs in a standing posture. SYN: orthostatic hypopiesis, postural h..
postural h. SYN: orthostatic h..

hypotensive
hypotensive (hi′po-ten′siv)

Characterized by low blood pressure or causing reduction in blood pressure.

hypotensor
hypotensor (hi-po-ten′ser, -sor)

SYN: depressor (4) .

hypothalamohypophysial
hypothalamohypophysial (hi′po-thal′a-mo-hi′po-fiz′e-al)

Relating to both the hypothalamus and the hypophysis.

hypothalamus
hypothalamus (hi′po-thal′a-mus) [TA]

The ventral and medial region of the diencephalon forming the walls of the ventral half of the third ventricle; it is delineated from the thalamus by the hypothalamic sulcus, lying medial to the internal capsule and subthalamus, continuous with the precommissural septum anteriorly and with the mesencephalic tegmentum and central gray substance posteriorly. Its ventral surface is marked by, from before backward, the optic chiasma, the unpaired infundibulum that extends by way of the infundibular stalk into the posterior lobe of the hypophysis, and the paired mamillary bodies. The h. consists of the anterior hypothalamic area [TA], dorsal hypothalamic area [TA], intermediate hypothalamic area [TA], lateral hypothalamic area [TA], and posterior hypothalamic area [TA], each of these containing specific nuclei. It has afferent fiber connections with the mesencephalon, limbic system, cerebellum, and efferent fiber connections with the same structures and with the posterior lobe of the hypophysis; its functional connection with the anterior lobe of the hypophysis is established by the hypothalamohypophysial portal system. The h. is prominently involved in the functions of the autonomic (visceral motor) nervous system and, through its vascular link with the anterior lobe of the hypophysis, in endocrine mechanisms; it also appears to play a role in neural mechanisms underlying moods and motivational states. SEE ALSO: pituitary gland. [hypo- + thalamus]

hypothenar
hypothenar (hi′po-the′nar, hi-poth′e-nar) [TA]

1. [NA] SYN: h. eminence. 2. Denoting any structure in relation with the h. eminence or its underlying collective components. [hypo- + G. thenar, the palm]

hypothermal
hypothermal (hi-po-ther′mal)

Denoting hypothermia.

hypothermia
hypothermia (hi′po-ther′me-a)

A body temperature significantly below 98.6°F (37°C). [hypo- + G. therme, heat]
accidental h. unintentional decrease in body temperature, especially in the newborn, infants, and elderly, particularly during operations.
moderate h. a body temperature of 23–32°C. induced by surface cooling.
profound h. a body temperature of 12–20°C.
regional h. reduction of the temperature of an extremity or organ by external cold or perfusion with cold blood or solutions.
total body h. the deliberate reduction of total body temperature, in order to reduce tissue metabolism.

hypothesis
hypothesis (hi-poth′e-sis)

A conjecture advanced for heuristic purposes, cast in a form that is amenable to confirmation or refutation by the conductance of definable experiments and the critical assembly of empiric data; not to be confused with assumption, postulation, or unfocused speculation. SEE ALSO: postulate, theory. [G. foundation, assumption fr. hypotithenai, to lay down]
adaptor h. a h., proposed by F.H.C. Crick, that an adaptor molecule must be present between the information-containing DNA and the protein being synthesized.
alternative h. in Neyman-Pearson testing of a h., the h. or family of hypotheses about the numerical value of a parameter if and only if the null h. is rejected as untenable.
autocrine h. that tumor cells containing viral oncogenes may have encoded a growth factor, normally produced by other cell types, and thereby produce the factor autonomously, leading to uncontrolled proliferation.
Avogadro h. SYN: Avogadro law.
Bayesian h. an array of surmised values of a parameter to be severally explored in the light of a current set of data, with logical symmetry being preserved among all. The merits of each h. entertained are based on quantity, the prior probability. The probability of the data conditional on the h. is computed as the conditional probability for each; the product of the two for each h. is the joint probability, and the ratio of each joint probability to the sum of all the joint probabilities is the posterior probability for that h.. Unlike the Neyman-Pearson test of hypotheses, the answer is a statement about the h., not about the sample conditional on the h.. No h. is preferred or prevails by default. The procedure may be applied recursively any number of times, as the data becomes available.
frustration-aggression h. the theory that frustration may lead to aggression, but that aggression is always the result of some form of frustration.
gate-control h. SYN: gate-control theory.
Goldie-Coldman h. a mathematic model that predicts that tumor cells mutate to a resistant phenotype at a rate dependent on their intrinsic genetic instability. The probability that a cancer would contain drug-resistant clones depends on the mutation rate and the size of the tumor. According to this h., even the smallest detectable cancers would contain at least 1 drug-resistant clone; therefore, the best chance of cure would be to use all effective chemotherapy drugs; in practice, this has meant using 2 different non–cross-resistant chemotherapy regimens in alternating cycles.
Gompertz h. a theory that the force of mortality increases in geometrical progression, being based on the assumption that the average exhaustion of an individual's power to avoid death is such that at the end of equal infinitely small intervals of time the individual loses equal proportions of the power to oppose destruction that were available at the commencement of each of these intervals.
insular h. obsolete theory of the origin of diabetes mellitus from destruction or loss of function of the islets of Langerhans in the pancreas.
Knudsen h. an explanation for the bilateral (and earlier) occurrence of hereditary retinoblastoma; if one tumor suppressor gene is mutated by inheritance, only one somatic mutation is needed inactivate the other allele. In the sporadic form, 2 mutations, which inactivate each allele, are necessary.
Lyon h. SYN: lyonization.
Makeham h. a development of Gompertz h. as to the force of mortality following some mathematical law. Makeham assumed that death was the consequence of two generally coexisting causes: 1) chance; 2) a deterioration or increased inability to withstand destruction. The first of these is constant, the second is an increasing geometrical progression.
Michaelis-Menten h. a h. that a complex is formed between an enzyme and its substrate (also known as the O'Sullivan-Tompson h.), which complex then decomposes to yield free enzyme and the reaction products (also referred to as the Brown h.), the latter step being the rate-determining step for the overall rate of substrate-product conversion. SEE ALSO: Michaelis-Menten constant, Michaelis-Menten equation.
mnemic h. the theory that stimuli or irritants leave definite traces (engrams) on the protoplasm of the animal, and when these stimuli are regularly repeated they induce a habit which persists after the stimuli cease. SYN: mnemic theory, mnemism, Semon-Hering theory.
monoamine h. the classical theory of the neurochemical basis of depression linking it to a deficiency of at least one of three monoamine neurotransmitters, norepinephrine, serotonin, or dopamine.
Neyman-Pearson statistical h. a formal conjecture about the numerical value of a parameter to be tested exclusively in the light of an immediate set of data without attention to prior knowledge or convictions and ignoring other sets of evidence treated in a similar fashion. The answer is a statement not about whether the h. is true but whether it is an acceptable explanation of the data or should be rejected in favor of another h..
Norton-Simon h. h. that a tumor is composed of populations of faster-growing cells, which are sensitive to therapy, and slower-growing, more resistant cells. Since only therapy that completely eradicates all tumor cells will be curative, this is most likely to occur with sequential, non–cross-resistant regimens. The initial regimen must be effective enough to result in a low residual tumor burden and is followed by one or more non–cross-resistant treatments to eradicate the remainder of the cancer.
null h. the statistical h. that one variable has no association with another variable or set of variables, or that two or more populations do not differ from each other; the statement that results do not differ from those that might be expected by the operation of chance alone; if rejected, it increases confidence in the h..
sequence h. that the amino acid sequence of a protein is determined by a particular sequence of nucleotides (the cistron) in the DNA of the organism producing the protein.
sliding filament h. the theory that the contracting muscle shortens because two sets of filaments slide past each other.
Starling h. the principle that net filtration through capillary membranes is proportional to the transmembrane hydrostatic pressure difference minus the transmembrane oncotic pressure difference; although well established, it is called Starling h. to distinguish it from Starling law of the heart.
upregulation/downregulation h. a theory of the neurochemical basis of depression (an elaboration of the monoamine h.) linking it to an increase in number (upregulation) of postsynaptic monoamine receptors, which are then effectively decreased in number (downregulation) as a result of antidepressant activity. SEE ALSO: monoamine h..
wobble h. wobble base, wobble.
zwitter h. that an amphoteric molecule ( e.g., an amino acid) has, at its isoelectric point, equal numbers of positive and negative charges, thus becoming a zwitterion.

hypothrombinemia
hypothrombinemia (hi′po-throm-bin-e′me-a)

Abnormally small amounts of thrombin in the circulating blood, resulting in bleeding tendency.

hypothromboplastinemia
hypothromboplastinemia (hi′po-throm′bo-plas-ti-ne′me-a)

Abnormally small amounts of thromboplastin in the blood, as a result of deficient quantities being released from the tissues.

hypothymia
hypothymia (hi′po-thi′me-a)

Depression of spirits; the “blues.” [hypo- + G. thymos, mind, soul]

hypothymic
hypothymic (hi-po-the′mik)

Denoting or characteristic of hypothymia.

hypothymism
hypothymism (hi′po-thi′mizm)

Obsolete term for inadequate function of the thymus.

hypothyroid
hypothyroid (hi′po-thi′royd)

Marked by reduced thyroid function.

hypothyroidism
hypothyroidism (hi′po-thi′royd-izm)

Diminished production of thyroid hormone, leading to clinical manifestations of thyroid insufficiency, including low metabolic rate, tendency to weight gain, somnolence and sometimes myxedema. SYN: athyrea (1) . [hypo- + G. thyreoeides, thyroid]
congenital h. lack of thyroid secretion. See infantile h..
infantile h. can be due to endemic congenital goiter, nonendemic cases are usually due to defective thyroidal embryogenesis, defective hypothalamic-pituitary function, congenital defects in thyroid hormone synthesis or action, or intrauterine exposure to goitrogenic agents. SYN: Brissaud infantilism, congenital myxedema, dysthyroidal infantilism, hypothyroid dwarfism, hypothyroid infantilism, infantile myxedema, myxedematous infantilism.
secondary h. h. that arises as a consequence of inadequate thyrotropin secretion by the anterior pituitary gland.

hypothyroxinemia
hypothyroxinemia (hi′po-thi-rok-sin-e′me-a)

A subnormal thyroxine concentration in the blood.

hypotonia
hypotonia (hi′po-to′ne-a)

1. Reduced tension in any part, as in the eyeball. 2. Relaxation of the arteries. 3. A condition in which there is a diminution or loss of muscular tonicity. SYN: hypotonicity (1) , hypotonus, hypotony. [hypo- + G. tonos, tone]
benign congenital h. nonprogressive h. of unknown etiology in infants and children; other known causes of hyptonia must be excluded.

hypotonic
hypotonic (hi-po-ton′ik)

1. Having a lesser degree of tension. 2. Having a lesser osmotic pressure than a reference solution, which is ordinarily assumed to be blood plasma or interstitial fluid; more specifically, refers to a fluid in which cells would swell. SYN: hypoisotonic.

hypotonicity
hypotonicity (hi′po-to-nis′i-te)

1. SYN: hypotonia. 2. A decreased effective osmotic pressure.

hypotonus
hypotonus, hypotony (hi′po-to′nus, hi-pot′o-ne)

SYN: hypotonia.

hypotrichiasis
hypotrichiasis (hi′po-tri-ki′a-sis)

1. SYN: hypotrichosis. 2. SYN: alopecia congenitalis. [hypo- + G. trichiasis, hairiness]

hypotrichosis
hypotrichosis (hi′po-tri-ko′sis)

A less than normal amount of hair on the head and/or body. SYN: hypotrichiasis (1) , oligotrichia, oligotrichosis. [hypo- + G. trichosis, hairiness]

hypotropia
hypotropia (hi-po-tro′pe-a)

An ocular deviation with one eye lower than the other. [hypo- + G. trope, turn]

hypotympanotomy
hypotympanotomy (hi′po-tim-pa-not′o-me)

Operative procedure for the excision, without sacrifice of hearing, of small tumors confined to the lower portion of the tympanic cavity. [hypo- + G. tympanon, tympanum, + tome, incision]

hypotympanum
hypotympanum (hi′po-tim′pa-num)

The lower part of the tympanic cavity. It is separated by a bony wall from the jugular bulb.

hypouresis
hypouresis (hi′po-u-re′sis)

Reduced flow of urine.

hypouricemia
hypouricemia (hi′po-u-ri-se′me-a)

Reduced blood concentration of uric acid.

hypouricuria
hypouricuria (hi′po-u′ri-ku′re-a)

Reduced excretion of uric acid in the urine.
hereditary renal h. an autosomal recessive disorder caused by defective reabsorption of urate in the renal proximal tubule.

hypovarianism
hypovarianism (hi′po-va′re-an-izm)

SYN: hypoovarianism.

hypoventilation
hypoventilation (hi′po-ven-ti-la′shun)

Reduced alveolar ventilation relative to metabolic carbon dioxide production, so that alveolar carbon dioxide pressure increases above normal. SYN: underventilation.

hypovitaminosis
hypovitaminosis (hi′po-vi′ta-min-o′sis)

A nutritional deficiency state characterized by relative insufficiency of one or more vitamins in the diet; manifested first by depletion of tissue levels, then by functional changes, and finally by appearance of morphologic lesions. Cf.:avitaminosis.

hypovolemia
hypovolemia (hi′po-vo-le′me-a)

A decreased amount of blood in the body. SYN: hyphemia. [hypo- + L. volumen, volume, + G. haima, blood]

hypovolemic
hypovolemic (hi′po-vo-le′mik)

Pertaining to or characterized by hypovolemia.

hypovolia
hypovolia (hi-po-vo′le-a)

Diminished water content or volume of a given compartment; e.g., extracellular h.. [hypo- + L. volumen, volume]

hypoxanthine
hypoxanthine (Hyp) (hi-po-zan′thin)

6-Oxypurine; purin-6(1H)-one;a purine present in the muscles and other tissues, formed during purine catabolism by deamination of adenine; elevated in molybdenum-cofactor deficiency. SYN: 6-hydroxypurine.
h. guanine phosphoribosyltransferase (HGPRT) SYN: h. phosphoribosyltransferase.
h. oxidase SYN: xanthine oxidase.
h. phosphoribosyltransferase an enzyme present in human tissue that converts h. and guanine to their respective 5′ nucleotides, with 5-phosphoribose 1-diphosphate as the ribose-phosphate donor; a partial deficiency of this enzyme can result in elevated purine biosynthesis resulting in gout; another level of deficiency is associated with Lesch-Nyhan syndrome. SYN: h. guanine phosphoribosyltransferase.

hypoxanthinosine
hypoxanthinosine (hi′po-zan-then′o-sen)

SYN: inosine.

hypoxemia
hypoxemia (hi-pok-se′me-a)

Subnormal oxygenation of arterial blood, short of anoxia. [hypo- + oxygen, + G. haima, blood]

hypoxia
hypoxia (hi-pok′se-a)

Decrease below normal levels of oxygen in inspired gases, arterial blood, or tissue, short of anoxia. [hypo- + oxygen]
anemic h. h. resulting from a decreased concentration of functional hemoglobin or a reduced number of erythrocytes; it is caused by hemorrhage or anemia of various types, or by poisoning with carbon monoxide, nitrites, or chlorates.
diffusion h. abrupt transient decrease in alveolar oxygen tension when room air is inhaled at the conclusion of a nitrous oxide anesthesia, because nitrous oxide diffusing out of the blood dilutes the alveolar oxygen.
hypoxic h. h. resulting from a defective mechanism of oxygenation in the lungs; may be caused by a low tension of oxygen, abnormal pulmonary function or respiratory obstruction, or a right-to-left shunt in the heart.
ischemic h. tissue h. characterized by tissue oligemia and caused by arterial or arteriolar obstruction or vasoconstriction.
oxygen affinity h. h. due to reduced ability of hemoglobin to release oxygen.
stagnant h. tissue h. characterized not by tissue oligemia (tissue blood volume being normal or even increased), but by intravascular stasis due to impairment of venous outflow or (in some instances) to decreased arterial inflow.

hypoxic
hypoxic (hi-pok′sik)

Denoting or characterized by hypoxia.

hypsarhythmia
hypsarhythmia, hypsarrhythmia (hip′sa-rith′me-a)

The abnormal and characteristically chaotic electroencephalogram commonly found in patients with infantile spasms. [G. hypsi, high, + a- priv. + rhythmos, rhythm]

hypsi- hypsi-, hypso-

High, height. [G. hypsos, height]

hypsibrachycephalic
hypsibrachycephalic (hip-se-brak′e-se-fal′ik)

Having a high broad head. [hypsi- + G. brachys, broad, + kephale, head]

hypsicephaly
hypsicephaly (hip-si-sef′a-le)

SYN: oxycephaly. [hypsi- + G. kephale, head]

hypsiconchous
hypsiconchous (hip-si-kon′kus)

Having a high orbit, with an orbital index above 85. [hypsi- + G. konchos, a shell, the upper part of the skull]

hypsiloid
hypsiloid (hip′si-loyd)

Y-shaped; U-shaped. SYN: upsiloid, ypsiliform. [G. upsilon (ypsilon)]

hypsistaphylia
hypsistaphylia (hip′si-sta-fil′e-a)

A condition in which the palate is high and narrow. [hypsi- + G. staphyle, uvula]

hypsistenocephalic
hypsistenocephalic (hip-si-sten′o-se-fal′ik)

Having a high, narrow head. [hypsi- + G. stenos, narrow, + kephale, head]

hypso- hypso-

See hypsi-.

hypsocephaly
hypsocephaly (hip-so-sef′a-le)

SYN: oxycephaly. [hypso- + G. kephale, head]

hypsochromic
hypsochromic (hip-so-krom′ik)

Denoting the shift of an absorption spectrum maximum to a shorter wavelength (greater energy). [hypso- + G. chroma, color]

hypsodont
hypsodont (hip′so-dont)

Having long teeth. [hypso- + G. odous, tooth]

hypurgia
hypurgia (hi-per′je-a)

A rarely used term for any minor factor(s) modifying the course of a disease for good or for ill, especially the former. [G. hypourgia, help, service, fr. hypo, + ergon, work]

Hyrtl
Hyrtl

Joseph, Austrian anatomist, 1811–1894. See H. anastomosis, H. foramen, H. loop, H. epitympanic recess, H. sphincter.

hyster- hyster-

See hystero-.

hysteralgia
hysteralgia (his′ter-al′je-a)

Pain in the uterus. SYN: hysterodynia, metrodynia. [hystero- + G. algos, pain]

hysteratresia
hysteratresia (his′ter-a-tre′ze-a)

Atresia of the uterine cavity, usually resulting from inflammatory endocervical adhesions.

hysterectomy
hysterectomy (his-ter-ek′to-me)

Removal of the uterus; unless otherwise specified, usually denotes complete removal of the uterus (corpus and cervix). [hystero- + G. ektome, excision]
abdominal h. removal of the uterus through an incision in the abominal wall. SYN: abdominohysterectomy.
abdominovaginal h. a combined vaginal and abdominal surgical approach that allows partial or complete removal of vagina, vulva, rectum, and perineum (abdominoperineal approach), as well as pelvic organs; usually done in cases of advanced pelvic cancer.
cesarean h. cesarean section followed by h.. SYN: Porro h..
laparoscopic-assisted vaginal h. vaginal h. in which the ovarian pedicle, broad ligament, and uterosacral ligaments are surgically severed using laparoscopic instruments and the procedure completed through a colpotomy done in the typical fashion.
modified radical h. an extended h. in which a portion of the upper vagina is removed; the ureters are exposed and pulled back laterally without dissection from the ureteral bed. SYN: TeLinde operation.
Porro h. SYN: cesarean h..
radical h. complete removal of the uterus, upper vagina, and parametrium.
subtotal h. SYN: supracervical h..
supracervical h. removal of the fundus of the uterus, leaving the cervix in situ. SYN: subtotal h..
vaginal h. removal of the uterus through the vagina without incising the wall of the abdomen. SYN: colpohysterectomy, vaginohysterectomy.

hysteresis
hysteresis (his-ter-e′sis)

1. Failure of either one of two related phenomena to keep pace with the other; or any situation in which the value of one depends upon whether the other has been increasing or decreasing. 2. The lag of a magnetic effect behind its cause. SYN: magnetic inertia. 3. The temperature differential that exists when a substance, such as reversible hydrocolloid, melts at one temperature and solidifies at another. 4. The basis of a type of cooperativity observed in many enzyme-catalyzed reactions in which the degree of cooperativity is associated with a slow conformational change of the enzyme. Cf.:allosterism, cooperativity. [G. h., a coming later]
static h. the difference in the value reached by a dependent variable at a particular constant value of the independent variable, depending on whether the latter value had been approached from above or below; e.g., in measuring the pressure volume relations of the lungs, if one completely expires and then inspires to a particular volume and holds it constant, the transpulmonary pressure required to maintain that lung volume is greater than if one had completely inspired and then expired to the same volume and held it constant.

hysteria
hysteria (his-ter′e-a, his-ter′)

A somatoform (psychoneurotic or psychosomatic) disorder in which there is an alteration or loss of physical functioning that suggests a physical disorder such as paralysis of an arm or disturbance of vision, but that is instead apparently an expression of a psychological conflict or need; a diagnostic term, referable to a wide variety of psychogenic symptoms involving disorder of function, which may be mental, sensory, motor, or visceral. See somatoform disorder. [G. hystera, womb, from the original notion of womb-related disturbances in women]
anxiety h. h. characterized by manifest anxiety.
conversion h. h. characterized by the substitution, through psychic transformation, of physical signs or symptoms for anxiety; generally restricted to such major symptoms as blindness, deafness, and paralysis, or lesser ones such as blurred vision and numbness. SYN: conversion h. neurosis, conversion neurosis, conversion reaction.
dissociative h. an unconscious process sometimes seen in patients with multiple personalities, or in h., in which a group of mental processes is separated from the rest of the thinking processes, resulting in an independent functioning of these processes and a loss of the usual relationships among them.
epidemic h. SYN: mass h..
mass h. 1. spontaneous, en masse development of identical physical and/or emotional symptoms among a group of individuals, as seen in a classroom of schoolchildren; 2. a socially contagious frenzy of irrational behavior in a group of people as a reaction to an event. SYN: epidemic h., mass sociogenic illness.

hysterical
hysterical, hysteric (his-ter′e-kal, -ter′ik)

Relating to or characterized by hysteria.

hysterics
hysterics (his-ter′iks)

An expression of emotion accompanied often by crying, laughing, and screaming.

hystero- hystero-, hyster-

1. The uterus. SEE ALSO: metr-, utero-. [G. hystera, womb (uterus)] 2. Hysteria. [G. hystera, womb (uterus)] 3. Later, following. [G. hysteros, later]

hysterocatalepsy
hysterocatalepsy (his′ter-o-kat′a-lep-se)

Hysteria with cataleptic manifestations.

hysterocele
hysterocele (his′ter-o-sel)

1. An abdominal or perineal hernia containing part or all of the uterus. 2. Protrusion of uterine contents into a weakened, bulging area of uterine wall. [hystero- + G. kele, hernia]

hysterocleisis
hysterocleisis (his′ter-o-kli′sis)

Operative occlusion of the uterus. [hystero- + G. kleisis, closure]

hysterocolposcope
hysterocolposcope (his′ter-o-kol′po-skop)

Instrument for inspection of the uterine cavity and vagina. [hystero- + G. kolpos, vagina, + skopeo, to view]

hysterocystopexy
hysterocystopexy (his′ter-o-sis′to-pek-se)

Attachment of both uterus and bladder to the abdominal wall to correct prolapse. [hystero- + G. kystis, bladder, + pexis, fixation]

hysterodynia
hysterodynia (his′ter-o-din′e-a)

SYN: hysteralgia. [hystero- + G. odyne, pain]

hysterogenic
hysterogenic, hysterogenous (his-ter-o-jen′ik, his-ter-oj′e-nus)

Causing hysterical symptoms or reactions. [hysteria + G. -gen, producing]

hysterogram
hysterogram (his′ter-o-gram)

1. X-ray examination of the uterus, usually using a contrast medium. 2. A recording of the strength of uterine contractions.

hysterograph
hysterograph (his′ter-o-graf)

Apparatus for recording the strength of uterine contractions.

hysterography
hysterography (his′ter-og′ra-fe)

1. Radiographic examination of the uterine cavity filled with a contrast medium. 2. Graphic procedure used to record uterine contractions. [hystero- + G. grapho, to write]

hysteroid
hysteroid (his′ter-oyd)

Resembling or simulating hysteria. [hystero- + G. eidos, resemblance]

hysterolysis
hysterolysis (his-ter-ol′i-sis)

Breaking up of adhesions between the uterus and neighboring parts. [hystero- + G. lysis, dissolution]

hysterometer
hysterometer (his-ter-om′e-ter)

A graduated sound for measuring the depth of the uterine cavity. SYN: uterometer. [hystero- + G. metron, measure]

hysteromyomectomy
hysteromyomectomy (his′ter-o-mi-o-mek′to-me)

SYN: myomectomy. [hysteromyoma + G. ektome, excision]

hysteromyotomy
hysteromyotomy (his′ter-o-mi-ot′o-me)

Incision into the muscles of the uterus. [hystero- + G. mys, muscle, + tome, incision]

hystero-oophorectomy
hystero-oophorectomy (his′ter-o-o′of-o-rek′to-me)

Surgical removal of the uterus and ovaries. [hystero- + G. oon, egg, + phoros, bearing, + ektome, excision]

hysteropathy
hysteropathy (his-ter-op′a-the)

Any disease of the uterus. [hystero- + G. pathos, suffering]

hysteropexy
hysteropexy (his′ter-o-pek-se)

Fixation of a displaced or abnormally movable uterus. SYN: uterofixation, uteropexy. [hystero- + G. pexis, fixation]
abdominal h. attachment of the uterus to the anterior abdominal wall.

hysteroplasty
hysteroplasty (his′ter-o-plas-te)

SYN: uteroplasty.

hysterorrhaphy
hysterorrhaphy (his-ter-or′a-fe)

Sutural repair of a lacerated uterus. [hystero- + G. rhaphe, suture]

hysterosalpingectomy
hysterosalpingectomy (his′ter-o-sal-pin-jek′to-me)

Operation for the removal of the uterus and one or both uterine tubes. [hystero- + G. salpinx, a trumpet, + ektome, excision]

hysterosalpingography
hysterosalpingography (his′ter-o-sal-ping-gog′ra-fe)

Radiography of the uterus and fallopian tubes after the injection of radiopaque material. SYN: hysterotubography, uterosalpingography, uterotubography. [hystero- + G. salpinx, a trumpet, + grapho, to write]

hysterosalpingo-oophorectomy
hysterosalpingo-oophorectomy (his′ter-o-sal-ping′go-o-of-o-rek′to-me)

Excision of the uterus, oviducts, and ovaries. [hystero- + G. salpinx, trumpet, + oon, egg, + phoros, bearing, + ektome, excision]

hysterosalpingostomy
hysterosalpingostomy (his′ter-o-sal-ping-gos′to-me)

Operation to restore patency of a uterine tube. [hystero- + G. salpinx, trumpet, + stoma, mouth]

hysteroscope
hysteroscope (his′ter-o-skop)

An endoscope used in direct visual examination of the uterine cavity. SYN: uteroscope. [hystero- + G. skopeo, to view]
contact h. h. with a graded refractive index rod lens; it does not require distension for visualization and affords very short focal length views; suitable for localizing hemorrhages.
flexible h. steerable flexible h. of small diameter for operative or diagnostic procedures, that does not require an outer sheath, has fiberoptics for visualization, and must be used with a distending gas.

hysteroscopy
hysteroscopy (his-ter-os′ko-pe)

Visual instrumental inspection of the uterine cavity. SYN: uteroscopy.

hysterospasm
hysterospasm (his′ter-o-spazm)

Spasm of the uterus.

hysterosystole
hysterosystole (his-ter-o-sis′to-le)

A delayed contraction of the heart; opposed to premature contraction or extrasystole. [G. hysteros, following, after, + systole, a contracting]

hysterothermometry
hysterothermometry (his′ter-o-ther-mom′e-tre)

Measurement of uterine temperature.

hysterotomy
hysterotomy (his-ter-ot′o-me)

Incision of the uterus. SYN: metrotomy, uterotomy. [hystero- + G. tome, incision]
abdominal h. transabdominal incision into the uterus. SYN: abdominohysterotomy.
vaginal h. incision into the uterus via the vagina. SYN: colpohysterotomy.

hysterotrachelectomy
hysterotrachelectomy (his′ter-o-trak-el-ek′to-me)

Removal of the cervix uteri. [hystero- + G. trachelos, neck, + ektome, excision]

hysterotracheloplasty
hysterotracheloplasty (his′ter-o-trak′e-lo-plas-te)

Plastic surgery of the cervix uteri. [hystero- + G. trachelos, neck, + plastos, formed, shaped]

hysterotrachelorrhaphy
hysterotrachelorrhaphy (his′ter-o-trak-e-lor′a-fe)

Sutural repair of a lacerated cervix uteri. [hystero- + G. trachelos, neck, + rhaphe, a seam]

hysterotrachelotomy
hysterotrachelotomy (his′ter-o-trak-e-lot′o-me)

Incision of the cervix uteri. [hystero- + G. trachelos, neck, + tome, incision]

hysterotubography
hysterotubography (his′ter-o-too-bog′ra-fe)

SYN: hysterosalpingography.

Hz
Hz

Abbreviation for hertz.