|Medical Dictionary - Dictionary of Medicine and Human Biology|
An unusually long uvula. [G. himas, strap, + -osis, condition]
hindbrain (hind′bran) [TA]
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.
Colloquialism for amniotic fluid in utero behind the presenting part of the fetus.
Frank, Jr., U.S. urologist, *1915. See H. syndrome.
William A., U.S. physician, 1883–1959. See H. test, Mueller-H. agar.
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.
SYN: rose hips.
Eugen von. See von H..
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]
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]
Relating to the 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
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.
Relating to, described by, or attributed to Hippocrates.
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.”
A system of medicine, attributed to Hippocrates and his disciples, based on the imitation of nature's processes in the therapeutic management of disease.
A salt or ester of hippuric acid.
The excretion of an abnormally large amount of hippuric acid in the urine.
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]
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.
Plural of hircus.
Offensive odor of the axillae. [L. hircus, goat]
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]
Julius, German ophthalmologist, 1843–1925. See H. method.
Isador, U.S. dentist, 1881–1965. See H. canals, under canal.
See under stain.
Harald, Danish physician, 1830–1916. See H. disease.
Relating to or characterized by hirsutism. [L. hirsutus, shaggy]
SYN: hirsutism. [Mod. L. fr. L. hirsutus, shaggy]
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.
Having or resembling fine hairs; term describing the filamentous protein polysaccharide coating of microvilli. See glycocalyx. [L. hirtus, hairy, shaggy]
An agent that kills leeches. [L. hirudo, leech, + caedo, to kill]
An antithrombin substance extracted from the salivary glands of the leech that has the property of preventing coagulation of the blood. [L. hirudo, leech]
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]
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]
1. The process of rendering the blood noncoagulable by the injection of hirudin. 2. The application of leeches.
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]
Wilhelm, Jr., German physician, 1863–1934. See H. band, H. bundle, H. bundle electrogram, H. spindle, Kent-H. bundle, H.-Tawara system.
Wilhelm, Sr., Swiss anatomist and embryologist in Germany, 1831–1904. See H. copula, H. line, H. perivascular space, isthmus of H..
Symbol for histidyl.
Symbol for histidino.
Symbol for histidine.
Philip, U.S. bacteriologist, 1868–1913. See H. stain.
SYN: amine oxidase (copper-containing).
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.
Indicating the absence of the normal response to histamine, especially in speaking of true gastric anacidity.
The presence of histamine in the circulating blood. [histamine + G. haima, blood]
The excretion of histamine in the urine. [histidine + G. ouron, urine]
SYN: histidine ammonia-lyase.
The aldehyde analog of histidine (–CHO replacing –COOH).
SYN: histidine ammonia-lyase.
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 (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 (&cbond;His) (his′ti-din-o)
The radical of histidine produced by removal of a hydrogen from a nitrogen atom; prefixed by Nα, Nτ, or Nπ.
The alcohol analog of histidine (–COOH becomes –CH2OH).
Excretion of considerable amounts of histidine in the urine; frequently observed in later months of pregnancy, and in histidinemia.
histidyl (His&cbond;) (his′ti-dil)
The acyl radical of histidine.
Tissue, especially connective tissue. [G. histion, web (tissue)]
A tissue-forming cell. SYN: histoblast. [histio- + G. blastos, germ]
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.
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.
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.
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