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Medical Dictionary


dolichocranial (dol-i-ko-kra′ne-al)
SYN: dolichocephalic.

dolichofacial (dol-i-ko-fa′shal)
SYN: dolichoprosopic.

dolichol (dol′i-kol)
Polyisoprenes in which the terminal member is saturated and oxidized to an alcohol, usually phosphorylated and often glycosylated; found in endoplasmic reticulum, but not in mitochondrial or plasma membranes; urinary levels are elevated in disorders exhibiting abnormal skin, rectal, or brain profiles in electron microscopy of biopsies. d. phosphate an intermediate in the glycosylation of proteins and lipids; contains 11–24 isoprene units; a product of the isoprenylation pathway; participates in the formation of glycosylphosphatidylinositol anchors of proteins in biomembranes.

dolichopellic, dolichopelvic (dol-i-ko-pel′ik, -pel′vik)
Having a disproportionately long pelvis; denoting a pelvis with a pelvic index above 95. [dolicho- + G. pellis, bowl (pelvis)]

dolichoprosopic, dolichoprosopous (dol-i-ko-pros-o′pik, -ko-pros′o-pus)
Having a disproportionately long face. SYN: dolichofacial. [dolicho- + G. prosopikos, facial]

dolichostenomelia (dol′i-ko-sten′o-me′le-a)
Narrow body habitus which, like arachnodactyly, is a common feature of several kinds of hereditary disorders of connective tissue. [dolicho- + G. stenos, narrow, + melos, limb]

dolichouranic, dolichuranic (dol′i-ko-u-ran′ik, dol-ik-u-)
Having a long palate, with a palatal index below 110. [dolicho- + G. ouranos, vault of the palate]

Richard, British epidemiologist, *1912. See Armitage-D. model.

dolor (do′lor)
Pain, as one of the four signs of inflammation (d., calor, rubor, tumor) enunciated by Celsus. [L.] d. capitis headache, especially due to changes in the scalp or bones rather than in the intracranial structures.

dolorific (do-lor-if′ik)

dolorimetry (do-lo-rim′e-tre)
The measurement of pain. [L. dolor, pain, + G. metron, measure]

dolorology (do-lor-ol′o-je)
The study and treatment of pain. [L. dolor, pain, + G. logos, study]

Abbreviation for 2,5-dimethoxy-4-methylamphetamine.

domain (do-man′)
1. Homologous unit of approximately 110–120 amino acids, groups of which make up the light and heavy chains of the immunoglobulin molecule; each serves a specific function. The light chain has two domains, one in the variable region and one in the constant region of the chain; the heavy chain has four to five domains, depending upon the class of immunoglobulin, one in the variable region and the remaining ones in the constant region. 2. A region of a protein having some distinctive physical feature or role. 3. An independently folded, globular structure composed of one section of a polypeptide chain. A d. may interact with another d.; it may be associated with a particular function. Domains can vary in size. [Fr. domaine, fr. L. dominium, property, dominion] dinucleotide d. SYN: dinucleotide fold.

Dombrock blood group
See Blood Groups appendix.


domestic violence
Intentionally inflicted injury perpetrated by and on family member(s); varieties include spouse abuse, child abuse, and sexual abuse, including incest. Various kinds of abuse, such as sexual abuse, also happen outside the family unit. The American Medical Association, like similar organizations in other countries, has issued advisory notices to physicians on the detection and treatment of d..

domiciliated (do-mi-sil′e-at-ed)
A state of close association of an organism within human abodes or activities, such that partial domestication results, leading to the organism's dependence on continued association with the human environment; this frequently results in the d. organism becoming a noxious pest, a vector, or an intermediate host of human disease. [L. domicilium, a dwelling]

dominance (dom′i-nans)
The state of being dominant. cerebral d. the fact that one hemisphere is dominant over the other and will exercise greater influence over certain functions; the left cerebral hemisphere is usually dominant in the control of speech, language and analytical processing, and mathematics, while the right hemisphere (usually nondominant) processes spatial concepts and language as related to certain types of visual images; handedness (right-handed people have left cerebral d.) is considered a general example of cerebral d.. false d. SYN: quasidominance. genetic d. denoting a pattern of inheritance of an autosomal mendelian trait due to a gene that always manifests itself phenotypically; generally, the phenotype in the homozygote is more severe than in the heterozygote, but details depend on what criterion of phenotyping is used. d. of traits an expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). At a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant.

dominant (dom′i-nant)
1. Ruling or controlling. 2. In genetics, denoting an allele possessed by one of the parents of a hybrid which is expressed in the latter to the exclusion of a contrasting allele (the recessive) from the other parent. [L. dominans, pres. p. of dominor, to rule, fr. dominus, lord, master, fr. domus, house]

domiodol (do-me′o-dol)
An organic form of iodine complexed with glycerol; used as a mucolytic/expectorant.

domiphen bromide (do′mi-fen)
An antiseptic.

domperidone (dom-per′i-don)
A dopamine antagonist (like chlorpromazine) with antiemetic properties.

Julius, German physician, 1870–1950. See D.-Landsteiner phenomenon, D.-Landsteiner cold autoantibody, Landsteiner-D. test.

Franz C., Dutch ophthalmologist, 1818–1889. See D. law, D. pressure, space of D..

Don Juan (don wan)
In psychiatry, a term used to denote males with compulsive sexual or romantic overactivity, usually with a succession of female partners. [legendary Spanish nobleman]

Don Juanism (don wan′izm)
See Don Juan.

Frederick G., English physical chemist, 1870–1956. See D. equilibrium, Gibbs-D. equilibrium.

Alfred, French physician, 1801–1878. See Donné corpuscle.

William L., Canadian pediatric pathologist, 1906–1984. See D. disease.

donor (do′ner)
1. An individual from whom blood, tissue, or an organ is taken for transplantation. 2. A compound that will transfer an atom or a radical to an acceptor; e.g., methionine is a methyl d.; glutathione is a glutamyl d.. 3. An atom that readily yields electrons to an acceptor; e.g., nitrogen, which will donate both electrons to a shared pool in forming a coordinate bond. [L. dono, pp. donatus, to donate, to give] hydrogen d. a metabolite from which hydrogen is removed (by a dehydrogenase system) and transferred by a hydrogen carrier to another metabolite, which is thus reduced. universal d. in blood grouping, a person belonging to group O; i.e., one whose erythrocytes do not contain either agglutinogen A or B and are, therefore, not agglutinated by plasma containing either of the ordinary isoagglutinins.

Charles, Irish surgeon, 1863–1951. See D. bodies, under body, Leishman-D. body.

H., 20th century German pediatrician and epileptologist. See D. syndrome.

dopa, DOPA, Dopa (do′pa)
An intermediate in the catabolism of l-phenylalanine and l-tyrosine, and in the biosynthesis of norepinephrine, epinephrine, and melanin; the l form, levodopa, is biologically active. See d. reaction. SYN: 3,4-dihydroxyphenylalanine. alpha methyl d. SYN: methyldopa. d. decarboxylase SYN: aromatic d-amino acid decarboxylase. decarboxylated d. SYN: dopamine. d. oxidase provisional name given the enzyme(s) catalyzing the formation of melanins from d.; it now appears that the copper-containing monophenol monooxygenases and/or catechol oxidases are responsible for the oxidation of l-tyrosine to d. and d. quinone. d. quinone an oxidation product of d. and an intermediate in the formation of melanin from tyrosine.

dopamine (DM) (do′pa-men)
An intermediate in tyrosine metabolism and precursor of norepinephrine and epinephrine; it accounts for 90% of the catecholamines; its presence in the central nervous system and localization in the basal ganglia (caudate and lentiform nuclei) suggest that d. may have other functions. Depletion of d. produces Parkinson disease. SYN: 3-hydroxytyramine, decarboxylated dopa. d. hydrochloride a biogenic amine and neural transmitter substance, used as a vasopressor agent for treatment of shock.

dopamine β-hydroxylase
SYN: dopamine β-monooxygenase.

dopamine β-monooxygenase
A copper-containing enzyme catalyzing oxidation of ascorbate and 3,4-dihydroxyphenylethylamine simultaneously by O2 to yield norepinephrine, dehydroascorbate, and water; a crucial step in catecholamine metabolism. The enzyme is stimulated by fumarate. SYN: dopamine β-hydroxylase.

dopaminergic (do′pa-min-er′jik)
Relating to nerve cells or fibers that employ dopamine as their neurotransmitter. [dopamine + G. ergon, work]

dope (dop)
1. Any drug, either stimulating or depressing, administered for its temporary effect, or taken habitually or addictively. 2. To administer or take such a drug. [Dutch, doop, sauce]

doping (dop′ing)
The administration of foreign substances to an individual; often used in reference to athletes who try to stimulate physical and psychological strength.

Johann Christian, Austrian mathematician and physicist, 1803–1853. See D. echocardiography, D. effect, D. phenomenon, D. shift, D. ultrasonography.

A diagnostic instrument that emits an ultrasonic beam into the body; the ultrasound reflected from moving structures changes its frequency (D. effect). Of diagnostic value in peripheral vascular and cardiac disease.

doraphobia (do-ra-fo′be-a)
Morbid fear of touching the skin or fur of animals. [G. dora, hide, skin, + phobos, fear]

P., Italian anatomist, *1872. See D. canal.

H., German physician, *1866. See D. sign.

Maurice L., 20th century Israeli dermatologist. See D.-Chanarin syndrome.

G., 20th century German neurologist. See Pette-D. disease.

dornase (dor′nas)
Obsolete contraction of deoxyribonuclease. SEE ALSO: streptodornase. pancreatic d. a stabilized deoxyribonuclease preparation from beef pancreas; used by inhalation in the form of aerosols to reduce thick mucopurulent secretions in certain bronchopulmonary infections.

Carl, Swiss climatologist, 1865–1942.

doromania (do-ro-ma′ne-a)
An abnormal desire to give presents. [G. doron, gift, + mania, insanity]

dorsa (dor′sa)
Plural of dorsum.

dorsabdominal (dor-sab-dom′i-nal)
Relating to the back and the abdomen.

dorsad (dor′sad)
Toward or in the direction of the back. [L. dorsum, back, + ad, to]

dorsal (dor′sal) [TA]
1. Pertaining to the back or any dorsum. SYN: tergal. 2. SYN: posterior (2) . 3. In veterinary anatomy, pertaining to the back or upper surface of an animal. Often used to indicate the position of one structure relative to another; i.e., nearer the back surface of the body. 4. Old term meaning thoracic, in a limited sense; e.g., d. vertebrae. [Mediev. L. dorsalis, fr. dorsum, back]

dorsalis (dor-sa′lis) [TA]
SYN: posterior (2) . [L.]

Marion, U.S. bacteriologist, 1872–1935. See D. culture egg medium.

dorsiduct (dor′si-dukt)
To draw backward or toward the back. [L. dorsum, back, + duco, pp. ductus, to draw]

dorsiflexion (dor-si-flek′shun)
Upward movement (extension) of the foot or toes or of the hand or fingers.

dorsiscapular (dor′si-skap′u-lar)
Relating to the dorsal surface of the scapula.

dorsispinal (dor′si-spi′nal)
Relating to the vertebral column, especially to its dorsal aspect.

dorsocephalad (dor′so-sef′a-lad)
Toward the occiput, or back of the head. [L. dorsum, back, + G. kephale, head, + L. ad, to]

dorsolateral (dor-so-lat′er-al)
Relating to the back and the side.

dorsolumbar (dor-so-lum′bar)
Referring to the back in the region of the lower thoracic and upper lumbar vertebrae.

dorsoventrad (dor-so-ven′trad)
In a direction from the dorsal to the ventral aspect.

dorsum, gen. dorsi, pl .dorsa (dor′sum, -si, -sa) [TA]
1. The back of the body. 2. The upper or posterior surface, or the back, of any part. SYN: tergum. [L. back] d. ephippii SYN: d. sellae. d. of foot [TA] the back, or upper surface, of the foot. SYN: d. pedis [TA] . d. of hand [TA] the back of the hand; surface of hand opposite the palm. d. linguae [TA] SYN: d. of tongue. d. manus [TA] SYN: d. of hand. d. nasi [TA] SYN: d. of nose. d. of nose [TA] the external ridge of the nose, looking forward and upward. SYN: d. nasi [TA] . d. pedis [TA] SYN: d. of foot. d. of penis [TA] the aspect of the penis opposite to that of the urethra. SYN: d. penis [TA] . d. penis [TA] SYN: d. of penis. d. scapulae the posterior surface of the scapula. d. sellae [TA] a square portion of bone on the body of the sphenoid posterior to the sella turcica or hypophysial fossa. SYN: d. ephippii. d. of tongue [TA] the back of the tongue; the upper surface of the tongue divided by the sulcus terminalis into an anterior two-thirds, the pars presulcalis (presulcal part), and a posterior one-third, the pars postsulcalis (postsulcal part). SYN: d. linguae [TA] .

dosage (do′sij)
1. The giving of medicine or other therapeutic agent in prescribed amounts. 2. The determination of the proper dose of a remedy. Cf.:dose. 3. In nuclear medicine, quantity of radiopharmaceutical given.

dose (dos)
1. The quantity of a drug or other remedy to be taken or applied all at one time or in fractional amounts within a given period. Cf.:dosage (2) . 2. In nuclear medicine, amount of energy absorbed per unit mass of irradiated material (absorbed d.). SEE ALSO: dosage (3) . [G. dosis, a giving] absorbed d. the amount of energy absorbed per unit mass of irradiated material at the target site; in radiation therapy, the former unit for absorbed d. is the rad (100 ergs/g); the current (SI) unit is the gray (1 J/kg or 100 rad). air d. SYN: exposure d.. bone marrow d. the cumulative d. to the blood-forming organ from therapeutic or nuclear fallout irradiation; the presumed leukemogenic d.. booster d. a d. given at some time after an initial d. to enhance the effect, said usually of antigens for the production of antibodies. cumulative d. the total d. resulting from repeated exposures to radiation or chemotherapy of the same part of the body or of the whole body. curative d. (CD, CD50) 1. the quantity of any substance required to effect the cure of a disease or that will correct the manifestations of a deficiency of a particular factor in the diet; 2. effective d. used with therapeutically applied compounds. SEE ALSO: CD50. SYN: therapeutic d.. daily d. the total amount of a remedy that is to be taken within 24 hours. depth d. the d. of radiation at a distance beneath the surface, including secondary radiation or scatter, in proportion to the d. at the surface. divided d. a definite fraction of a full d.; given repeatedly at short intervals so that the full d. is taken within a specified period, usually one day. SYN: fractional d.. effective d. (ED) 1. the d. that produces a specific effect; when followed by a subscript (generally “ED50”), it denotes the d. having such an effect on a certain percentage ( e.g., 50%) of the test animals; ED50 is the median effective d.; 2. in radiation protection, the sum of the equivalent doses in all tissues and organs of the body weighted for tissue effects of radiation. The SI unit of effective d. is the sievert (Sv) (=100 rem). 3. in diagnostic radiology, if a patient weighing W absorbs A joules of energy, and the experimentally derived ratio of effective d. to energy absorbed in an anthropomorphic phantom with mass M is R, then the effective d. is A·R· M/W. This formula results in a larger value for children despite their lesser absorption of radiation. epilation d. the minimum amount of radiation sufficient to produce hair loss, usually in 10 to 14 days. equianalgesic d. the qualitative ratio between actual milligram potency of comparable analgesics required to achieve the equivalent therapeutic effect. equivalent d. in radiation protection, the absorbed d. averaged over a tissue or organ and weighted for the quality of the type of radiation. The unit of equivalent d. is the sievert. erythema d. the minimum amount of x-rays or other form of radiation sufficient to produce erythema; historically, this d. was indicated by the Sabouraud meter as the B tint, the Holzknecht as 5(5H), the Hampson as 4, and the Kienbock as 10. exit d. the exposure d. of radiation leaving a body opposite the portal of entry. exposure d. the radiation d., expressed in roentgens, delivered at a point in free air. SYN: air d.. fractional d. SYN: divided d.. gonad d. the exposure d. to the male or female gonad, usually from incidental secondary radiation in diagnostic or therapeutic irradiation, or from whole-body irradiation. SYN: gonadal d.. gonadal d. SYN: gonad d.. initial d. SYN: loading d.. integral d. the total energy absorbed by the body, the product of the mass of tissue irradiated and the absorbed d.; unit, the gram rad. L doses a group of terms that indicate the relative activity or potency of diphtheria toxin; the L doses are distinctly different from the minimal lethal d. and minimal reacting d., inasmuch as the latter two represent the direct effects of toxin, whereas the L doses pertain to the combining power of toxin with specific antitoxin. [“L” for L. limes, limit, boundary] L+ d., L+ d. alternatives for L&dag;, the limes tod d. of diphtheria toxin, i.e., the smallest amount of toxin that, when mixed with one unit of antitoxin and injected subcutaneously into a 250-g guinea pig, results in death of the animal within 96 hours (based on the average in a series); on theoretical grounds, one might expect that the difference between the L+ and L0 doses would be identical to 1 MLD, but this is not so in actual practice; with various toxic filtrates, the difference may range from several to more than 100 MLDs, indicating that the toxin-antitoxin combination is not a firm chemical union that occurs in constant proportions. lethal d. (LD) the d. of a chemical or biologic preparation ( e.g., a bacterial exotoxin or a suspension of bacteria) that is likely to cause death; it varies in relation to the type of animal and the route of administration; when followed by a subscript (generally “LD50” or median lethal d.), it denotes the d. likely to cause death in a certain percentage ( e.g., 50%) of the test animals; median lethal d. is LD50, absolute lethal d. is LD100, and minimal lethal d. is LD05. Lf d., Lf d. the limes flocculation d. of diphtheria toxin, i.e., the smallest amount of toxin that, when mixed with one unit of antitoxin, yields the most rapid flocculation in the Ramon test (in vitro); in general, the Lf d. is slightly less than the Lr d.. Lo d., Lo d. the limes nul d. of diphtheria toxin, i.e., the largest amount of toxin that, when mixed with one unit of antitoxin and injected subcutaneously into a 250-g guinea pig, yields no recognizable reaction in the average of a series; actually, the Lod. is usually recorded as the one that causes a barely perceptible local edema at the site of inoculation. loading d. a comparatively large d. given at the beginning of treatment to start getting the effect of a drug, especially one with slow clearance thus requiring a long period to achieve stable blood levels without a high initial d.. SYN: initial d.. Lr d., Lr d. the limes reacting d. of diphtheria toxin, i.e., the smallest amount of toxin that, when mixed with one unit of antitoxin and injected intracutaneously in the shaved skin of a susceptible guinea pig, yields a minimal, positive reaction and inflammation localized to the region of the injection; the Lrd. closely approximates the Lod., as would be expected, inasmuch as a slight excess of unneutralized toxin results in a reaction. maintenance d. maintenance drug therapy. maximal d. the largest amount of a drug or physical procedure that an adult can take with safety. maximal permissible d. See maximum permissible d.. maximum permissible d. (MPD) defined by the International Commission on Radiological Protection as the greatest d. of radiation which, in the light of present knowledge, is not expected to cause detectable bodily injury to persons at any time during their lifetime. This d. has been reduced with each Commission report. The MPD is given in terms of acute or chronic exposure of the whole body or of organs, systems, or regions of the body and differs for persons who are occupationally exposed versus the public at large. maximum tolerated d. d. that produces grade 3 (severe) or grade 4 (life-threatening) toxicity in 30% or fewer of the patients tested. median effective d. (ED50) effective d.. minimal d. the smallest amount of a drug or physical procedure that will produce a desired physiologic effect in an adult. minimal infecting d. (MID) the smallest quantity of infectious material regularly producing infection; usually expressed as I.D.50, the quantity causing infection in 50% of a suitable series of animals or cells (cell cultures). minimal lethal d. (MLD, mld) 1. the minimal d. of a toxic substance or infectious agent that is lethal, as assayed in various experimental animals ( e.g., the least amount of diphtheria toxin that, on an average, kills a 250-g guinea pig within 96 h after subcutaneous inoculation); when followed by a subscript (generally “MLD50”), denotes the minimal d. that is lethal to a certain percentage ( e.g., 50%) of animals so assayed; 2. lD05. See lethal d.. minimal reacting d. (MRD, mrd) the minimal d. of a toxic substance causing a reaction, as manifested in the skin of a series of susceptible test animals; the assay is based on the development of a characteristic, minimal but definite, “standard,” focal inflammation (congestion and edema, induration, degenerative changes, and desquamation of epidermal cells). optimum d. the d. of a drug or radiation that will produce the desired effect with minimum likelihood of undesirable symptoms. preventive d. the smallest amount of any substance that will prevent occurrence of symptoms of a disease or the consequences of a lack of a particular factor in the diet. sensitizing d. in experimental anaphylaxis, the antigenic inoculum that renders an animal susceptible (sensitive) to anaphylactic shock following a subsequent inoculum (shocking d.) of the same antigen (anaphylactogen). shocking d. in experimental anaphylaxis, the inoculum of antigen that causes anaphylactic shock in an animal sensitized by a previous inoculum (sensitizing d.) of the same antigen. skin d. the absorbed d. of radiation delivered to the skin surface. therapeutic d. SYN: curative d.. tissue culture infectious d. (TCID50, TCD50) the quantity of a cytopathogenic agent, such as a virus, that will produce a cytopathic effect in 50% of the cultures inoculated. tolerance d. the largest d. of a remedy that can be accepted without the production of injurious symptoms.

dosimeter (do-sim′e-ter)
A device for measuring radiation, especially x-rays. [G. dosis, dose, + metron, measure]


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