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Medical Dictionary


hormonogenic (hor′mo-no-jen′ik)
Pertaining to the formation of a hormone. SYN: hormonopoietic.

hormonopoiesis (hor′mo-no-poy-e′sis)
SYN: hormonogenesis. [hormone + G. poiesis, production]

hormonopoietic (hor′mo-no-poy-et′ik)
SYN: hormonogenic.

hormonoprivia (hor′mo-no-priv′e-a)
Obsolete term meaning partial or total deprivation of hormones. [hormone + G. privus, deprived of]

hormonotherapy (hor′mo-no-thar′a-pe)
Treatment with hormones.

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..

Johann F., Swiss ophthalmologist, 1831–1886. See H. syndrome, H. pupil, Bernard-H. syndrome, H.-Trantas dots, under dot.

William E., U.S. anatomist, 1793–1853. See H. muscle, H. teeth, under tooth.

horny (horn′e)
Of the nature or structure of horn. SYN: keratinous (2) .

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 (ho-rip-i-la′shun)
Erection of the fine hairs on contraction of the arrectores pilorum. [L. horreo, to bristle, + pilus, hair]

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 (hors′fli)
See Tabanus, Anthomyia canicularis.

horsepower (hors′pow-er)
A unit of power, 550 foot-pounds/sec, or 745.7 W.

Frank L., Jr., U.S. physician, 1906–1971. See Tamm-H. mucoprotein, Tamm-H. protein.

Sir Victor A.H., English surgeon, 1857–1916. See H. bone wax.

hor. som.
Abbreviation for L. hora somni, before sleep, at bedtime.

Pio del Rio, Spanish neurohistologist in South America, 1882–1945. See H. cells, under cell, H. neuroglia stain.

Bayard T., U.S. physician, *1895. See H. arteritis, H. cephalalgia, H. headache.

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 (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 (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 (hos′pi-tal-i-za′shun)
Confinement in a hospital as a patient for diagnostic study and treatment.

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..

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 (hows′fli)
See Musca, Fannia.

house officer
A person with a medical degree employed by a hospital to provide service to patients while receiving training in a medical specialty.

Bernardo A., Argentinian physiologist and Nobel laureate, 1887–1971. See H. animal, H. phenomenon, H. syndrome.

John, Irish physician, 1802–1845. See H. folds, under fold, H. muscle.

Jacob, Dutch ophthalmologist, 1710–1786. See canal of H..

John Eager, U.S. internist and endocrinologist, 1902–1985. See H. test, Ellsworth-H. test.

William H., U.S. physiologist, 1860–1945. See H. unit, H.-Jolly bodies, under body.

John, British surgeon, 1781–1841. See H. lacunae, under lacuna.

Heinrich F., Polish anatomist and histologist, 1834–1907. See H. anastomoses, under anastomosis, H. canals, under canal, Sucquet-H. canals, under canal.

Abbreviation for haptoglobin.

Abbreviation for human placental lactogen.

Abbreviation for high-pressure liquid chromatography; high-performance liquid chromatography.

Abbreviation for human papillomavirus.

Symbol for ubiquinol.

Abbreviation for health risk assessment.

Abbreviation for high-resolution computed tomography.

Abbreviation for Health Resources and Services Administration.

Abbreviation for hormone replacement therapy.

Abbreviation for L. hora somni, before sleep, at bedtime.

Abbreviation for high-grade squamous intraepithelial lesion.

Abbreviation for heat shock proteins, under protein.

Abbreviation for herpes simplex virus.

Abbreviation for 5-hydroxytryptamine.

Abbreviation for total hyperopia.

Abbreviation for human T-cell lymphoma/leukemia virus.

Abbreviation for T-cell lymphotrophic virus type I; human lymphotropic virus, type 1.

Abbreviation for T-cell lymphotrophic virus type II; human lymphotropic virus, type 2.

Old abbreviation for human T-cell lymphotropic virus type III. See human immunodeficiency virus.

hU, hu
Abbreviation for dihydrouridine.

Ambrosius A.W., Dutch zoologist and comparative anatomist, 1853–1915. See H. protochordal knot.

Hucker-Conn stain
See under stain.

Arthur Cyril, British ophthalmologist, 1875–1962. See H.-Stähli line.

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.

Alexander F., German anatomist, 1802–1842. See H. ligament.

G.J., Dutch physician, *1879. See Pelger-H. nuclear anomaly.

Karl, German surgeon, 1838–1882. See H. maneuver.

Carl Gustav von, German physician, 1840–1908. See H. equation.

Pierre C., French surgeon, 1804–1873. See H. canal, H. circle, H. sinus.

Max, U.S. urologist, 1873–1947. See H. test.

Edgar, U.S. cardiologist, *1904.

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
SYN: 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 (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 (hu-mek′tant)
1. Moistening. 2. A substance used to obtain a moistening effect ( e.g., glycerin solution).


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