halo - Harpagophytum
[L., from Gr. halōs disk of the sun or moon]
1. a luminous or colored circle, such as the colored circle seen around a light in glaucoma.
2. a ring seen around the macula luteae in ophthalmoscopical examination.
3. the imprint of the ciliary processes upon the vitreous body.
4. a metal or plastic band that encircles the head or neck, providing support and stability as part of a halo orthosis.
a colored circle appearing around a light, caused by the wearing of contact lenses; see also Fick's phenomenon.
, glaucomatous h.
peripapillary atrophy seen in severe or chronic glaucoma.
a zone of variable width surrounding the optic papilla, caused by exposure of various elements of the choroid as a result
of senile atrophy of the pigmented epithelium.
[Gr. hals, gen. halos salt]
a combining form denoting relationship to a salt.
plural of halobacterium.
a family of aerobic, rod-shaped and coccoid bacteria, made up of chemo-organotrophic organisms that require at least 8 per
cent and in most cases 17 to 23 per cent sodium chloride for growth. These extremely halophilic bacteria, which belong to
the archaeobacteria group, do not contain peptidoglycan in their cell walls and differ from other bacteria in ribosomal RNA
and cell lipid structures. They contain carotenoid pigments, and they are found in pools of evaporating sea water and material
preserved with sea salts. The family contains the genera Halobacterium and Halococcus.
[halo- + bacterium]
a genus of gram-negative, aerobic, pleomorphic, rod-shaped bacteria of the family Halobacteriaceae that require a high concentration
of sodium chloride (15 per cent or greater) for growth and are found in evaporating sea water, salt lakes, and heavily salted
protein materials. They contain a purple pigment (bacteriorhodopsin), which powers a system of photosynthesis, and some contain
a red carotenoid pigment (bacterioruberin). The type species is H. salina´rium.
Any member of the genus Halobacterium.
halobetasol propionate (hal·o·be·ta·sol pro·pi·o·nate)
a very high potency synthetic corticosteroid used topically for the relief of inflammation and pruritus in corticosteroid-responsive dermatoses.
[halo- + coccus]
a genus of gram-negative aerobic bacteria of the family Halobacteriaceae, made up of coccoid cells that require a high concentration
of sodium chloride (15 per cent or greater) for growth. They contain a red carotenoid pigment and are found in salted meats
and fish. The type species is H. morrhu´ae.
any skin eruption caused by a halide.
trademark for a combination preparation of fluoxymesterone and ethinyl estradiol.
[halo- + L. durare to endure]
capable of existing in a medium containing a high concentration of salt.
halofantrine hydrochloride (hal·o·fan·trine hy·dro·chlor·ide)
an antimalarial chemically related to quinine and mefloquine, effective against the asexual forms of Plasmodium in the blood stream; used in the treatment of acute malaria caused by P. falciparum and P. vivax.
trademark for preparations of halcinonide.
[halo- + -gen]
an element of a closely related chemical family, all of which form similar (saltlike) compounds in combination with sodium
and most other metals. The halogens are bromine, chlorine, fluorine, iodine, and astatine.
incorporation of a halogen into a chemical compound.
a genus of small plants of the family Polygonaceae, which were introduced into the southwestern United States; they contain
soluble oxalates that can be highly poisonous to grazing animals, causing respiratory difficulty, hemorrhage, and hypocalcemia. The major
species is H. glomera´tus (Bieb.) C. A. Mey. See also oxalate poisoning, under poisoning.
[halo- + -oid]
saltlike; derived from or resembling a halogen.
[halo + -meter]
1. an instrument for measuring ocular halos; see halo (def. 1).
2. an instrument for estimating the size of erythrocytes by measuring the halos formed around them when a beam of light shines
on them and is diffracted.
the measurement of halos with a halometer.
[USP] an antipsychotic agent of the butyrophenone group, which also has antiemetic, hypotensive, and hypothermic actions; used especially
in the management of psychoses and for the control of the vocal utterances and tics of Gilles de la Tourette's syndrome, administered
orally and intramuscularly.
the decanoate ester of haloperidol, having the same actions as the base but of longer duration; administered intramuscularly
in maintenance therapy for psychotic disorders.
a microorganism that requires a high concentration of salt for optimal growth.
[halo- + -philic]
pertaining to or characterized by an affinity for salt; applied to microorganisms which require a high concentration of salt
for optimal growth.
a synthetic topical antifungal used in the treatment of various forms of tinea.
trademark for a preparation of fluoxymesterone.
trademark for a preparation of haloprogin.
[USP] a potent inhalational anesthetic, widely used for induction and maintenance of general anesthesia; it is nonflammable, induction
and recovery are smooth and rapid, and the depth of anesthesia is rapidly altered.
BAN for halquinols.
a topical anti-infective compound, consisting of a mixture of 5,7-dichloro-8-quinolinol, 5-chloro-8-quinolinol, and 7-chloro-8-quinolinol
in proportions resulting naturally from chlorination of 8-quinolinol; it has antiamebic, antifungal, and antibacterial actions.
Halsted's mastectomy, operation, suture (Hal·sted's mastectomy, operation, suture)
[William Stewart Halsted, American surgeon, 18521922]
see under operation and suture and see radical mastectomy, under mastectomy.
Haltia-Santavuori disease (Hal·tia-San·ta·vu·ori disease)
[M. Haltia, Finnish physician, 20th century; Pirkko Santavuori, Finnish physician, 20th century]
see under disease.
Haly Abbas (Haly Ab·bas)
see Ali Abbas.
a pharyngeal form of fascioliasis occurring in the Middle East, caused by eating raw animal livers infected with Fasciola; young adult worms attach to the pharyngeal mucosa and produce pain, bleeding, and facial and neck edema.
Ham's test (Ham's test)
[Thomas Hale Ham, American physician, born 1905]
acidified serum test.
[Gr. hama together + mēlon apple]
a genus of trees and shrubs of the family Hamamelidaceae. H. virginia´na is witch hazel; an extract of its twigs is made into the astringent liquid also called witch hazel.
the dried leaves of Hamamelis virginiana, which have been used as an astringent; see also witch hazel (def. 2).
a defect in tissue combination during development.
pertaining to or exhibiting a hamartia.
[Gr. hamartia fault]
a combining form denoting relationship to a defect or to a hamartoma.
[hamarto- + blastoma]
a tumor developing from a hamartoma.
[hamart- + -oma]
a benign tumorlike nodule composed of an overgrowth of mature cells and tissues that normally occur in the affected part,
but with disorganization and often with one element predominating.
fibrous h. of infancy
a benign, nonencapsulated tumor, sometimes present at birth but usually appearing during the first year of life, most frequently
in the shoulder, axilla, or upper arm. It is a firm, painless, skin-colored nodule composed of well-defined fibrous trabeculae,
immature mesenchymal tissue, and mature adipose cells; invasion of the surrounding subcutaneous tissue frequently occurs.
a benign tumor, usually a circumscribed nodule or coin lesion in peripheral lung parenchyma or in a bronchus; tissue types
and degree of calcification vary.
sclerosing epithelial h.
the development of multiple hamartomas.
pertaining to a disturbance in growth of a tissue in which the cells of a circumscribed area outstrip those of the surrounding
shaped like a hook (hamulus). Cf. uncinate.
2. os hamatum.
Hamburger phenomenon (interchange) (Ham·bur·ger phenomenon (interchange))
[Hartog Jakob Hamburger, Dutch physiologist, 18591924]
Hamilton's test (Ham·il·ton's test)
[Frank Hastings Hamilton, American surgeon, 18131886]
see under test.
Hamman's disease, syndrome, sign (Ham·man's disease, syndrome, sign)
[Louis Hamman, American physician, 18771946]
see pneumomediastinum, and see under sign.
Hamman-Rich syndrome (Ham·man-Rich syndrome)
[L. Hamman; Arnold Rice Rich, American pathologist, 18931968]
idiopathic pulmonary fibrosis.
1. an instrument with a head designed for striking blows.
a small rubber-headed hammer used to tap tendons, nerves, or muscles to test various reflexes, such as the patellar reflex.
Hammond's disease (Ham·mond's disease)
[William Alexander Hammond, American neurologist, 18281900]
any member of four genera of the rodent family Muridae; genera used as laboratory animals are Cricetulus, Cricetus, and Mesocricetus.
Cricetulus griseus, a species that was formerly a common laboratory animal and is the source of the Chinese hamster ovary (CHO) cell line.
Cricetus cricetus, a species native to Europe and the Middle East, commonly used as a laboratory animal.
Mesocricetus auratus, a species widely used as a laboratory animal and pet. Called also Syrian h.
Syrian cardiomyopathic h.
an inbred strain of Syrian hamster used as an animal model of hypertrophic cardiomyopathy.
1. one of the tendons that bound the popliteal fossa laterally and medially.
2. pertaining to or related to these tendons; see under muscle.
the tendons of the gracilis, sartorius, and two other muscles.
the tendon of the biceps flexor femoris.
shaped like a hook.
[L. “little hook”]
[TA] hook: anatomical nomenclature for a long, thin, curved structure.
h. laminae spiralis.
h. of ethmoid bone
processus uncinatus ossis ethmoidalis.
, h. fronta´lis
ala cristae galli.
h. of hamate bone
h. ossis hamati.
lacrimal hamulus: the hooklike process on the anterior part of the inferolateral border of the lacrimal bone, articulating
with the maxilla.
h. la´minae spira´lis
hamulus of spiral lamina: the hooklike upper end of the osseous spiral lamina.
h. os´sis hama´ti
hook of hamate bone: a hooklike process on the volar surface of the hamate bone, to which numerous structures are attached. Called also hamulus of hamate bone.
pterygoid hamulus: a hooklike process on the inferior extremity of the medial pterygoid plate of the sphenoid bone, around
which the tendon of the tensor veli palatini muscle passes.
h. of spiral lamina
h. laminae spiralis.
Hancock's amputation (operation) (Han·cock's amputation (operation))
[Henry Hancock, English surgeon, 18091880]
see under amputation.
Hand's disease (Hand's disease)
[Alfred Hand, Jr., American pediatrician, 18681949]
Hand-Schüller-Christian disease; see under disease.
Hand-Schüller-Christian disease, syndrome (Hand-Schül·ler-Chris·tian disease, syndrome)
(hand shūl´ər kris´chən)
[A. Hand, Jr.; Arthur Schüller, Austrian neurologist, 18741958; Henry Asbury Christian, American physician, 18761951]
see under disease and syndrome.
the distal region of the upper limb, including the carpus, metacarpus, and digits. In offical terminology, called manus.
a hand with the thumb permanently extended.
a hand in which the ring and little fingers are flexed; there is weakness of abduction and adduction of the index and middle
fingers but they can be extended normally, and the thumb remains normal; seen in ulnar paralysis and syringomyelia.
a congenital anomaly of the hand in which the division between the fingers extends into the metacarpus; often there are just
two large digits, one on either side of the cleft. Called also lobster-claw h. or deformity, split h., split-hand deformity, and main fourchée. See also EEC syndrome, under syndrome.
an occupational disorder seen sometimes in those who use vibratory tools, and apparently caused by the multitude of concussions.
The hands are painful and dark blue in color, but blanch on exposure to cold.
stiffness of the hand resulting from edema accompanying trauma.
Marinesco's succulent h.
a soft, swollen, cyanotic, and cold hand caused by thickening and edema of the subcutaneous tissues; seen in syringomyelia.
Called also main succulente and Marinesco's sign. See also Morvan's syndrome (def. 2), under syndrome.
an anomaly in which there are two crude hands growing from a common wrist.
a hand in which several fingers are fused together and have a common nail.
a condition in which the thumb lies in adduction and extension and cannot be opposed so as to touch the tips of the other
fingers, because of thenar muscle weakness, sometimes caused by lesions of the median nerve. Called also main en singe and monkey paw.
the contraction of the hand in tetany, flexed at the wrist with fingers at the metacarpophalangeal joints but extended at
the interphalangeal joints, the thumb being strongly flexed into the palm; so called because of a dubious resemblance to the
position assumed by the hand of the obstetrician when examining the vagina.
a pawlike hand marked by telescoping of the fingers caused by absorption of the phalanges; it may occur in chronic inflammatory
a paresthetic feeling as if the hand were still present after amputation.
a hand markedly atrophied and held in a position of extension: seen in progressive muscular atrophy; called also main en squelette.
the thick square hand of myxedema and acromegaly.
contracture or other incapacity of the hand from frostbite; so called from its occurrence in the trenches during World War
the characteristic hand of achondroplasia: the fingers are relatively of the same length, and there is a peculiar separation
of the second and third fingers at the second phalangeal joint, causing the fingers to spread out.
a peculiar position of the hand in which the hand appears poised for writing; seen in paralysis agitans.
H and E (H and E)
hematoxylin-eosin; see Stains and Staining Methods, under stain.
the preferential use in voluntary motor acts of the hand of one side; see dextrality and sinistrality.
the preferential use in voluntary motor acts of the left hand.
the preferential use in voluntary motor acts of the right hand.
any physical or mental defect or characteristic, congenital or acquired, preventing or restricting a person from participating
in normal life or limiting his capacity to work.
a part of a larger object enabling it to be grasped with the hand; see also manubrium.
h. of malleus
a hand-held device that engages rotary instruments used for removing tooth structures, cleaning teeth, and polishing dental
restorations, connected to the dental engine by an adjustable arm in the case of a belt-driven instrument or by flexible tubing
if air driven.
a handpiece in which two or more angles or bends are used to set the shaft at a desired angle in order to access hard-to-reach
areas of the oral cavity.
hereditary angioneurotic edema; see hereditary angioedema, under angioedema.
a shred of eponychium on a proximal or lateral nail fold.
Hanhart's syndrome (Han·hart's syndrome)
[Ernst Hanhart, Swiss physician, 18911973]
see under syndrome.
Hannover's canal (Han·no·ver's canal)
[Adolph Hannover, Danish anatomist, 18141894]
see under canal.
Hanot-Chauffard syndrome (Ha·not-Chauf·fard syndrome)
[Victor Charles Hanot, French physician, 18441896; Anatole Marie Emile Chauffard, French physician, 18551932]
see under syndrome.
Hansemann macrophages (Han·se·mann macrophages)
[David Paul von Hansemann, German pathologist, 18581920]
von Hansemann cells.
Hansen's bacillus, disease (Han·sen's bacillus, disease)
[Gerhard Henrik Armauer Hansen, Norwegian physician, 18411912]
see Mycobacterium leprae and leprosy.
a genus of yeasts of the family Saccharomycetaceae, formerly called Willia. H. ano´mala is a species commonly found in soil and as normal flora in the human respiratory and intestinal tracts.
[Hantaan River, Korea]
a genus of viruses of the family Bunyaviridae that cause epidemic hemorrhagic fever or pneumonia, comprising at least 20 species included in one serogroup and unclassified species. Each species appears to
have a single rodent species as a host; transmission to humans is believed to be by contact, direct or indirect, with the
excreta of infected rodents.
a genus of octopus. H. maculo´sa is the venomous blue-ringed octopus (q.v.).
[Gr. haphē touch + algesia]
a type of tactile hyperesthesia in which normally painless touch sensations cause pain, as in Pitres' sign (def. 1) or certain mental disorders.
[Gr. haphē touch + -phobia]
irrational fear of being touched.
[Gr. haploos simple, single]
a combining form meaning simple or single.
a genus of small fish. H. pan´chax, called ikan kapala timah in Malay, is a species placed in fishponds in Indonesia to eat the larvae of Anopheles mosquitoes.
[haplo- + diploidy]
the state in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are
diploid, as in honeybees.
[haplo- + Gr. odous tooth]
having molar teeth without cusps or ridges.
1. having a single set of chromosomes, as normally carried by a gamete, or having one complete set of nonhomologous chromosomes.
In man, the haploid number is 23. Symbol, n. Cf. diploid (def. 1).
2. an individual or cell having only one member of each pair of homologous chromosomes.
sharing a haplotype; having the same alleles at a set of closely linked genes on one chromosome.
the condition of being haploidentical.
the state of having only one member of each pair of homologous chromosomes.
[Gr. haploun to make single]
a haploid individual.
a genus of composite-flowered plants (family Compositae). Several species, such as H. hetero´phyllus, the rayless goldenrod, contain the toxin tremetol and cause trembles in cattle and sheep.
[haplo- + -pathy]
an uncomplicated disease.
that phase in the life history of germ cells when the nuclei are haploid.
[hapl- + -opia]
single vision; the condition in which an object looked at is seen single and not double.
a genus of minute trematodes found in tropical areas; they are intestinal parasites of dogs, cats, and other vertebrates.
H. tai´chui infects birds and mammals, occasionally including humans.
[haplo- + -scope]
an instrument that presents two separate views to the two eyes so that the views may be seen as one integrated view; it is
used to measure, test, or stimulate various binocular functions.
a haploscope that uses mirrors to separate or displace the fields of vision of the two eyes.
pertaining to a haploscope; stereoscopic.
an antigen derived from the fungus Emmonsia parva.
[haplo- + type]
1. a set of alleles of a group of closely linked genes, such as the HLA complex, which is usually inherited as a unit.
2. the genetic constitution of an individual at a set of closely linked genes on a given chromosome.
Hapsburg jaw, lip, disease (Haps·burg jaw, lip, disease)
[Hapsburg, a German-Austrian royal family, including rulers of several European states, such as Austria (12781918) and Spain (15041700)]
see under jaw and lip, and see hemophilia.
[Ger., from Gr. haptein to fasten]
a small molecule, not antigenic by itself, that can react with antibodies of appropriate specificity and elicit the formation
of such antibodies when conjugated to a larger antigenic molecule, usually a protein, called in this context the carrier or
schlepper. Antibody production involves activation of B lymphocytes by the hapten and helper T lymphocytes by the carrier.
pertaining to or caused by haptens.
[hapt- + -phobia]
[Gr. haptikos able to lay hold of]
the study of the sense of touch; see touch.
[Gr. haptein to fasten, grasp, touch]
a combining form denoting relationship to touch or to binding.
a 100,000-dalton plasma glycoprotein with alpha electrophoretic mobility that irreversibly binds free hemoglobin resulting
in prompt removal of the hemoglobin-haptoglobin complex by the liver, preventing loss of free hemoglobin in the urine. Haptoglobin
levels are decreased by hemolysis and increased owing to increased synthesis in conditions resulting in extensive tissue damage
and necrosis. Haptoglobin has two major genetic variants, designated Hp 1 and Hp 2.
[hapto- + -meter]
an instrument for measuring sensitivity to touch.
Harada syndrome (Ha·ra·da syndrome)
[Einosuke Harada, Japanese ophthalmologist, 18921947]
Vogt-Koyanagi-Harada syndrome; see under syndrome.
1. an allergic skin reaction caused by bites of the sand fly Phlebotomus papatasii, seen in the Middle East, and characterized by urticarial and inflammatory papules and blisters. Immunity usually follows
the initial exposure. Called also urticaria multiformis endemica.
2. popular name for any of various other skin eruptions.
Harden-Young ester (Har·den-Young ester)
[Sir Arthur Harden, English biochemist, 18651940; William John Young, Australian biochemist, 20th century]
1. induration (def. 2).
3. the procedure of rendering tissue firm, so that it may be more readily cut for purposes of microscopic examination.
h. of arteries
popular term for arteriosclerosis.
Harder's glands (Har·der's glands)
[Johann Jacob Harder, Swiss physician, 16561711]
see under gland.
named for Johann Jacob Harder, as harderian fossa or harderian glands.
a severe variant of hereditary coproporphyria differing in having earlier onset of attacks, excretion of harderoporphyrin
in the feces, and virtual absence of coproporphyrinogen oxidase activity.
an intermediate in heme biosynthesis, formed in the conversion of coproporphyrinogen to protoporphyrinogen and excreted excessively
in the feces in harderoporphyria.
1. a quality of water produced by soluble salts of calcium and magnesium or other substances which form an insoluble curd with
soap and thus interfere with its cleansing power.
2. the quality of firmness produced by cohesion of the particles composing a substance, as evidenced by its inflexibility or
resistance to indentation, distortion, or scratching. See also hardness number, under number.
3. the quality of x-rays that determines their penetrating power; hardness depends on wavelength: the shorter the wavelength
the harder the rays and the greater their penetrating power.
4. the degree of refraction of the residual gas in a glass tube: the higher the vacuum the shorter the wavelength of the resulting
diamond pyramid h.
Vickers hardness number.
hardness of water not removed by boiling; it is usually due to sulfates and chlorides.
hardness of water removed by boiling; it is due to soluble bicarbonates, which lose CO2 on boiling and precipitate as normal carbonates.
Hardy-Weinberg law (Har·dy-Wein·berg law)
[Godfrey Harold Hardy, British mathematician, 18771947; Wilhelm Weinberg, German physician, 18621937]
see under law.
Hare's syndrome (Hare's syndrome)
[Edward Selleck Hare, British surgeon, 18121838]
Pancoast's syndrome (def. 1).
1. a person or animal decorated like Harlequin, an old stock character in European comedies who wore colorful checkered clothing.
2. coral snake.
an alkaloid that has hallucinogenic properties, found in the seeds of African rue (Peganum harmala) and the South American vine Banisteria caapi.
an alkaloid that has hallucinogenic properties, found in the seeds of African rue (Peganum harmala) and the South American vine Banisteria caapi. Called also banisterine.
the state of working together smoothly.
proper occlusion of the teeth occurring in various positions of the mandible.
occlusal h., functional
such occlusion of the teeth in all positions of the mandible during mastication as will provide the greatest masticatory efficiency
without imposing undue strain or trauma on the supporting tissues.
trademark for preparations of deserpidine.
the combination of straps, bands, and other pieces that forms the working gear of a draft animal, or a device resembling such
a device used to correct hip dislocations in infants with developmental dysplasia of the hip, consisting of a set of straps that hold the hips in flexion and abduction.
[L. harpago grappling hook + Gr. phyton plant]
a genus of herbs native to southern Africa, including H. procum´bens, the devil's claw, which is used medicinally.