Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

histotroph
(his´to-trōf) the sum total of nutritive material derived from maternal tissue other than the blood, utilized by the early embryo.

histotrophic
(his″to-tro´fik) encouraging formation of tissue. pertaining to histotroph.

histotropic
(his″to-tro´pik) having affinity for tissue cells.

histrelin
(his-trel´in) a synthetic preparation of gonadotropin-releasing hormone, used as the acetate ester in treatment of precocious puberty.

histrionic personality disorder
a personality disorder characterized by dramatic, attention-seeking, overly reactive, and intensely expressed behavior. Individuals with this disorder are prone to emotional display, such as angry outbursts and tantrums. They are often perceived by others as shallow and fickle; in their relationships they may be superfici...

Hitzelberger sign
anesthesia of medial, posterior, or superior areas of the external auditory canal caused by an acoustic neuroma that is pressing against the facial nerve.

Hitzig test
(for functioning of the vestibular apparatus) the positive electrode of a galvanic current is applied just in front of the ear being examined while the negative electrode is held in the hand of a patient who stands with feet together and eyes closed. A current of 5 milliamperes causes a leaning toward the positive pole in...

HIV
human immunodeficiency virus. HIV-positive having a positive reaction on a test for the human immunodeficiency virus; used to indicate that an individual has been infected with the human immunodeficiency virus but does not yet have AIDS. Persons who are HIV-positive require sensitive cou...

HIV encephalopathy
HIV-related encephalopathy a progressive primary encephalopathy caused by infection with human immunodeficiency virus type I, manifested by a variety of cognitive, motor, and behavioral abnormalities. Called also AIDS encephalopathy.

HIV protease inhibitor
any of a group of antiretroviral drugs active against the human immunodeficiency virus; they prevent protease-mediated cleavage of viral polyproteins, causing production of immature viral particles that are noninfective. Examples include indinavir sulfate, nelfinavir mesylate, ritonavir, and saquinavir.

HIV wasting syndrome
wasting syndrome.

HIV-associated nephropathy
renal pathology in patients infected with the human immunodeficiency virus, similar to focal segmental glomerulosclerosis, with proteinuria, enlarged kidneys, and dilated tubules containing proteinaceous casts; it may progress to end-stage renal disease within weeks.

hives
(hīvz) urticaria.

Hl
latent hyperopia.

HLA antigens
the human major histocompatibility complex, located on the short arm of chromosome 6. Five loci have been identified, designated HLA-A, HLA-B, HLA-C, HLA-D, and HLA-DR (D related), each with multiple alleles, designated by numerals (such as HLA-B5). Provisionally identified alleles are designated by the letter w (such as HLA-Bw...

HLA complex
the human major histocompatibility complex, which contains the hla antigens.

Hm
manifest hyperopia.

hMG
human menopausal gonadotropin.

HMG-CoA reductase inhibitors
a group of drugs that competitively inhibit the enzyme that catalyzes the rate-limiting step in cholesterol biosynthesis, and are used to lower plasma lipoprotein levels in the treatment of hyperlipoproteinemia. Called also statins.

HMO
health maintenance organization.

hnRNA
heterogeneous nuclear RNA.

hnRNP proteins
a diverse group of approximately 30 proteins that associate with nascent heterogeneous nuclear RNA (hnRNA), as it is transcribed, forming heterogeneous nuclear ribonucleoprotein particles; they are involved in packaging, splicing, and other posttranscriptional processing of pre-mRNAs, staying bound until the mature mRNAs are tr...

Ho
holmium.

hoarseness
(hors´nis) a rough quality of the voice.

Hodgkin cells
Reed-Sternberg cells.

Hodgkin disease
(hoj´kin) Hodgkin lymphoma a form of malignant lymphoma characterized by painless, progressive enlargement of the lymph nodes, spleen, and lymphoid tissues generally. It often begins in a lymph node on the side of the neck and then spreads through the body. The first sign of the disease usually is an enlargement of lymph nodes...

Hodgkin sarcoma
(hoj´kin) Hodgkin disease, lymphocyte depletion type.

Hodgson disease
(hoj´son) aneurysmal dilatation of the proximal part of the aorta; it is sometimes accompanied by dilatation of the heart.

hodoneuromere
(ho″do-noor´o-mēr) a segment of the embryonic trunk with its pair of nerves and their branches.

Hoehne sign
absence of uterine contractions during delivery despite repeated injections of oxytocics, regarded as a sign of rupture of the uterus.

Hofbauer cells
large, globular cells filled with vacuoles and large spherical nuclei, found in the connective tissue core of the chorionic villi of the placenta; they are probably macrophages.

Hoffa disease
(haw´fә) traumatic proliferation of fatty tissue (solitary lipoma) in the knee joint.

Hoffa operation
Hoffa-Lorenz operation Lorenz operation.

Hoffmann atrophy
Werdnig-Hoffmann spinal muscular atrophy.

Hoffmann phenomenon
increased excitability to electrical stimulation in the sensory nerves; the ulnar nerve is usually tested. Called also Hoffmann sign.

Hoffmann reflex
Hoffmann sign (def. 2).

Hoffmann sign
(hawf´mahn) increased mechanical irritability of the sensory nerves in tetany; the ulnar nerve is usually tested. a sudden nipping of the nail of the index, middle, or ring finger produces flexion of the terminal phalanx of the thumb and of the second and third phalanx of some other finger; called also dig...

Hoffmann test
(for tyrosine) add mercuric nitrate to the suspected liquid and boil it; then add nitric acid with a little nitrous acid. A red color is produced if tyrosine is present, and a red precipitate is seen.

Hoffmann-Werdnig syndrome
(hawf´mahn vәrd´nig) Werdnig-Hoffmann spinal muscular atrophy.

Hofmeister test
(for leucine) warm the suspected liquid with mercurous nitrate; if leucine is present, metallic mercury is deposited. (for peptones) mix phosphotungstic and hydrochloric acids; let the mixture stand twenty-four hours, and filter. With this reagent a solution containing peptones with no albumin will afford a precip...

holandric
(hol-an´drik) inherited exclusively through the male descent; transmitted through genes located on the Y chromosome.

holandric gene
one that is located on the Y chromosome and thus appears only in males.

holandric inheritance
Y-linked inheritance.

holiday heart syndrome
paroxysms of arrhythmias, most commonly atrial fibrillation, in patients without overt cardiomyopathy after a weekend bout of alcoholic consumption, especially during the year-end holiday season.

holistic
(ho-lis´tik) pertaining to totality, or to the whole; holistic health includes the physical, mental, social, and spiritual aspects of a person's life as an integrated whole.

holistic medicine
a system of medicine that considers the human being as an integrated whole or functioning unit.

Hollenhorst plaques
atheromatous emboli containing cholesterol crystals in the retinal arterioles.

Holmes sign
rebound phenomenon.

Holmes-Adie syndrome
(hōmz´ a´de) Adie syndrome.

holmium
(Ho) (hōl´me-әm) a chemical element, atomic number 67, atomic weight 164.930.

holoacardius
(hōl″o-ә-kahr´de-әs) a malformed monozygotic twin fetus in which the heart is entirely absent.

holoblastic
(hōl″o-blas´tik) undergoing cleavage in which the entire zygote participates; completely dividing.

holocrine
(ho´lo-krin) wholly secretory, denoting that type of glandular secretion in which the entire secreting cell, along with its accumulated secretion, forms the secreted matter of the gland, as in the sebaceous glands. See also apocrine and merocrine.

holocrine gland
one whose discharged secretion contains the entire secreting cells.

holodiastolic
(hōl″o-di″ә-stol´ik) pertaining to the entire diastole.

holoendemic
(hōl″o-en-dem´ik) endemic at a high level in a population, affecting most of the children but affecting the adults in the population less often; see also hyperendemic.

holoendemic disease
an endemic disease occurring at a high level in a population so that most of the children are affected, the adults in the same population then being less so. Cf. hyperendemic disease.

holoenzyme
(hōl″o-en´zīm) the active compound formed by combination of a coenzyme and an apoenzyme.

holoprosencephaly
(hōl″o-pros″әn-sef´ә-le) a developmental anomaly consisting of failure of cleavage of the prechordal mesoderm with a deficit in the forebrain and midline facial development; in the severe form there may be cyclopia. It is sometimes associated with trisomy 13 syndrome.

holorachischisis
(hōl″o-rә-kis´kĭ-sis) fissure of the entire vertebral column with prolapse of the spinal cord.

holosystolic
(hōl″o-sis-tol´ik) pertaining to the entire systole.

Holt-Oram syndrome
(hōlt´ or´әm) autosomal dominant heart disease of varying severity, usually an atrial or ventricular septal defect, associated with skeletal malformation (hypoplastic thumb and short forearm). Called also heart-hand syndrome.

Holth operation
excision of the sclera by punch operation.

Holthouse hernia
an inguinal hernia that has turned outward into the groin.

Homans operation
a formerly common treatment for elephantiasis and other types of massive edema of the lower limb, consisting of excision of subcutaneous tissue and redundant skin on the lateral and medial aspects.

Homans sign
(ho´manz) discomfort behind the knee on forced dorsiflexion of the foot; a sign of thrombosis in the lower limb.

homatropine
(ho-mat´ro-pēn) an anticholinergic and antimuscarinic producing sympathetic blockade effects similar to but weaker than those of atropine; the hydrobromide salt is used as a mydriatic and cycloplegic and the methylbromide salt is used as an inhibitor of gastric spasm and secretion.

home
(hōmz) a place where someone lives. nursing home long-term care facility. informal misnomer for a residential care home. residential care home , rest home a residence where room, board, and personal care are provided f...

home health care
services provided by a certified agency using an interdisciplinary team to meet the needs of patients being cared for in out-of-hospital settings such as private homes, boarding homes, hospices, shelters, and so on.

Homén syndrome
(ho´mān) postconcussional syndrome.

homeomorphous
(ho″me-o-mor´fәs) of like form and structure.

homeopathy
(ho″me-op´ә-the) a system of therapeutics founded by Samuel Hahnemann (1755–1843). Diseases are treated by drugs that are capable of producing in healthy persons symptoms like those of the disease to be treated, the drug being administered in minute doses. adj., homeopath´ic., adj.

homeoplasia
(ho″me-o-pla´zhә) formation of new tissue like that normal to the part. adj., homeoplas´tic., adj.

homeostasis
(ho″me-o-sta´sis) the tendency of a biological system to maintain relatively constant conditions in its internal environment while it continuously interacts with and adjusts to changes on the outside. Through homeostatic mechanisms, the human body maintains body temperature, the osmotic pressure of the blood, and ...

homeotherapy
(ho″me-o-ther´ә-pe) treatment with a substance similar to the causative agent of the disease.

homeotherm
(ho´me-o-thәrm″) an animal that exhibits homeothermy; a warm-blooded animal. endotherm.

homeothermy
(ho´me-o-thur″me) the maintenance of a constant body temperature despite changes in the environmental temperature, as seen in mammals and birds. adj., homeother´mal, homeother´mic., adj.

homergic
(hōm-ur´jik) having the same effect; said of two drugs each of which produces the same overt effect.

homocentric
(ho″mo-sen´trik) having the same center or focus.

homochronic
(ho″mo-kron´ik) homochronous (ho-mok´ro-nәs) occurring at the same age or life stage in successive generations. denoting the same age or stage of development, as tissue from one organism transplanted into another of the developmental stage.

homocitrulline
(ho″mo-sit´roo-lēn) an unusual amino acid that is not normally present in urine but is excreted in hyperornithinemia-hyperammonemia-homocitrullinuria syndrome.

homocitrullinuria
(ho″mo-sit″roo-lĭ-nu´re-ә) excess of homocitrulline in the urine; see hyperornithinemia-hyperammonemia-homocitrullinuria syndrome.

homocyclic
(ho″mo-sik´lik) (-si´klik) having or pertaining to a closed chain or ring formation that contains only atoms of the same element.

homocysteine
(ho″mo-sis´te-ēn) a sulfur-containing amino acid homologous with cysteine and produced by demethylation of methionine; it can form cystine or methionine.

homocystine
(ho″mo-sis´tēn) a homologue of cystine that results from demethylation of methionine.

homocystinuria
(ho″mo-sis″tin-u´re-ә) an inborn error of metabolism of sulfur-containing amino acids due to lack of the enzyme cystathionine synthase; it is characterized by homocystine in the urine and by mental retardation, enlargement of the liver, displacement of the lens of the eye, and cardiovascular and skelet...

homocytotropic
(ho″mo-si″to-tro´pik) having an affinity for cells of individuals of the same species.

homodromous
(ho-mod´ro-mәs) moving or acting in the same or in the usual direction.

homoeroticism
(ho″mo-ә-rot´ĭ-siz-әm) sexual feeling directed toward a person of the same sex. adj., homoerot´ic., adj.

homogamete
(ho″mo-gam´ēt) one of two gametes of the same size and structure, as the X chromosome in the human female.

homogametic
(ho″mo-gә-met´ik) pertaining to production of gametes containing only one kind of sex chromosome, as in the human female.

homogenate
(ho-moj´ә-nāt) material obtained by homogenization.

homogeneity
(ho″mo-jә-ne´ĭ-te) the state of being homogeneous.

homogeneous
(ho″mo-je´ne-әs) of uniform quality, composition, or structure.

homogeneous system
a system or structure made up of parts which cannot be mechanically separated, as a solution.

homogenesis
(ho″mo-jen´ә-sis) reproduction by the same process in each generation. adj., homogenet´ic, adj. .

homogenize
(ho-moj´ә-nīz) to convert into material that is of uniform quality or consistency throughout; to render homogeneous.

homogenized milk
milk treated so the fats form a permanent emulsion and the cream does not separate.

homogentisic acid
(ho″mo-jen-tis´ik) 2,5-dihydroxyphenyl acetic acid, an intermediate product in the metabolism of tyrosine and phenylalanine, excreted in the urine in the inborn error of metabolism known as phenylketonuria.

homograft
(ho´mo-graft) allograft.