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Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


dihydrotestosterone (di-hi′dro-tes-tos′ter-on)
SYN: stanolone.

dihydrouracil (di-hi-dro-ur′a-sil)
5,6-D.;a reduction product of uracil and one of the intermediates of uracil catabolism.

dihydrouracil dehydrogenase
SYN: dihydropyrimidine dehydrogenase.

dihydrouridine (hU, hu, D) (di-hi-dro-ur′i-den)
Uridine in which the 5,6-double bond has been saturated by addition of two hydrogen atoms; a rare constituent of transfer ribonucleic acids.

Prefix denoting addition of two hydroxyl groups; as a suffix, becomes -diol.

dihydroxyacetone (di′hi-drok-se-as′e-ton)
HOCH2–CO–CH2OH; 1,3-dihydroxy-2-propanone;glycerone; the simplest ketose. SYN: glycerulose. d. phosphate (DHAP) one of the intermediates in the glycolytic pathway and in fat biosynthesis; glycerone phosphate. d. phosphate acyltransferase an enzyme that catalyzes an important step in plasmalogen biosynthesis; an acyl group from acyl-CoA is transferred to d. phosphate producing free coenzyme A and 1-acyldihydroxyacetone phosphate.

2,8-dihydroxyadenine (di-hi-drok′se-ad′e-nen)
An insoluble minor product of adenine catabolism that is elevated in individuals with an absence of adenine phosphoribosyltransferase.

dihydroxyaluminum aminoacetate (di-hi-drok′se-a-loo′mi-num am′i-no-as′e-tat)
Basic aluminum glycinate, a basic aluminum salt of aminoacetic acid containing small amounts of aluminum hydroxide and aminoacetic acid; used as an antacid in hyperchlorhydria and peptic ulcer.

dihydroxyaluminum sodium carbonate
A gastric antacid.

1,25-dihydroxyergocalciferol (di-hi-drok′se-er′go-kal-sif′er-ol)
A biologically active metabolite of vitamin D2. SYN: ercalcitriol.

3,4-dihydroxyphenylalanine (di-hi-droks′e-fen-il-al′a-nen)
SYN: dopa.

diiodide (di-i′o-did)
A compound containing two atoms of iodine per molecule.

Prefix indicating two atoms of iodine. [G. di, + ioeides, violet flower color]

diiodohydroxyquin (di-i-o′do-hi-drok′si-kwin)
C9H5I2NO;an antiprotozoal agent, used in the treatment of intestinal amebiasis. SYN: diodoquin.

diiodotyrosine (DIT) (di′i-o-do-ti′ro-sen)
An intermediate in the biosynthesis of thyroid hormone.

diisopromine (di-i-so-pro′men)
A cholagogue. SYN: disopromine.

diisopropyl fluorophosphate (DFP) (di-i-so-pro′pil flor-o-fos′fat)
SYN: isofluorphate.

diisopropyl iminodiacetic acid (DISIDA) (di-e-so-pro′pil im′i- no-di-a-se-tik)
A radiopharmaceutical labeled with 99mTc, used for cholescintigraphy. SYN: disofenin.

2,6-diisopropyl phenol
SYN: propofol.

A product of catabolism of vitamin C; formed from l-dehydroascorbate; it has no vitamin C activity.

diketohydrindylidene-diketohydrindamine (di-ke′to-hi-drin-dil′i-den di-ke′to-hi-drind′a-men)
The colored product formed in the reaction of an α-amino acid and ninhydrin (triketohydrindene hydrate); a reaction used in the quantitative assay of α-amino acids.

diketone (di-ke′ton)
A molecule containing two carbonyl groups; e.g., acetylacetone (CH3COCH2COCH3).

diketopiperazines (di-ke′to-pi-per′a-zenz)
A class of organic compounds with a closed ring structure formed from two α-amino acids by the joining of the α-amino group of each to the carboxyl group of the other, with the loss of two molecules of water.

Abbreviation for L. dilue, dilute, or L. dilutus, diluted.

dilaceration (di-las-er-a′shun)
Displacement of some portion of a developing tooth which is then further developed in its new relation, resulting in a tooth with sharply angulated root(s). [L. di-lacero, pp. laceratus, to tear in pieces, fr. lacer, mangled]

dilatancy (di-la′tan-se)
An increasing viscosity with increasing rate of shear accompanied by volumetric expansion. [L. dilato, to dilate]

dilatation (dil-a-ta′shun)
SYN: dilation. digital d. use of the finger or finger-tip to enlarge an orifice or opening, such as enlarging the orifice of a sclerosed mitral valve surgically.

dilatator (dil′a-ta-ter, -tor)
SYN: dilator.

dilate (di′lat)
To perform or undergo dilation.

dilation (di-la′shun)
1. Physiologic or artificial enlargement of a hollow structure or opening. 2. The act of stretching or enlarging an opening or the lumen of a hollow structure. SYN: dilatation. [L. dilato, pp. dilatatus, to spread out, dilate] d. and extraction a form of abortion in which the cervix is dilated and the fetus extracted in pieces using surgical forceps; technique used to complete a second trimester spontaneous abortion or as a form of induced abortion. post-stenotic d. d. of an artery, most commonly the pulmonary artery or the aorta, distal to an area of narrowing. d. and suction SYN: suction curettage. urethral d. increasing the caliber of the urethra by passage of a dilator.

dilation and curettage (D & C)
Dilation of the cervix and curettement of the endometrium.

dilation and evacuation (D & E)
Dilation of the cervix and removal of the products of conception.

dilator (di′la-ter)
1. An instrument designed for enlarging a hollow structure or opening. 2. A muscle that pulls open an orifice. 3. A substance that causes dilation or enlargement of an opening or the lumen of a hollow structure. SEE ALSO: bougie. SYN: dilatator. Chevalier-Jackson d. an esophageal d. that passes through a rigid endoscope. Hanks dilators uterine dilators of solid metal construction. Hegar dilators a series of cylindrical bougies of graduated sizes used to dilate the cervical canal. hydrostatic d. an instrument for dilating esophageal strictures; fluid pressure is delivered into a flexible area of the instrument placed in the stricture to establish a uniform dilating pressure. d. iridis SYN: d. pupillae muscle. Kollmann d. a metallic expandable instrument used to dilate urethral strictures. pneumatic d. any of a variety of catheters fitted with distal balloons that can be inflated to desired pressures for overcoming obstructions in hollow viscera; most often used to rupture the lower esophageal sphincter to treat achalasia. Pratt dilators cylindrical metal rods of graduated sizes used to dilate the cervical canal. d. of pupil SYN: d. pupillae muscle. Walther d. a gently curved instrument that tapers to an increased diameter, used to dilate the female urethra.

dildo, dildoe (dil′do)
An artificial penis; an object having the approximate shape and size of an erect penis, and commonly made of wood, plastic, or rubber; utilized for sexual pleasure.


dill oil
A volatile oil distilled from the fruit of Anethum graveolens (family Umbelliferae); a carminative.

diloxanide furoate (di-lok′sa-nid fu′ro-at)
An amebicide used in the treatment of dysentery.

diltiazem hydrochloride (dil-ti′a-zem)
A calcium channel blocking agent used as a coronary vasodilator, an antiarrhythmic, and antihypertensive.

1. Ingredient in a medicinal preparation that lacks pharmacologic activity but is pharmaceutically necessary or desirable. In tablet or capsule dosage forms, this may be lactose or starch; it is particularly useful in increasing the bulk of potent drug substances whose mass is too small for dosage form manufacture or administration. May be a liquid for the dissolution of drug(s) to be injected, ingested, or inhaled. 2. Denoting that which dilutes; the diluting agent.

dilute (dil.) (di-loot′)
1. To reduce a solution or mixture in concentration, strength, quality, or purity. 2. Diluted; denoting a solution or mixture so effected. [L. di-luo, to wash away, d.]

dilution (di-loo′shun)
1. The act of being diluted. 2. A diluted solution or mixture. 3. In microbiologic techniques, a method for counting the number of viable cells in a suspension; a sample is diluted to the point where an aliquot, when plated, yields a countable number of separate colonies.

Abbreviation for L. dimidius, one-half.

dimazole dihydrochloride (di′ma-zol)
SYN: diamthazole dihydrochloride.

dimazon (di-ma′zon)
An azo compound occurring in red crystals; used with petrolatum as an ointment to stimulate epithelial cell proliferation and thus promote the healing of superficial wounds.

dimelia (di-me′le-a)
Congenital duplication of the whole or a part of a limb. [G. di-, two, + melos, limb]

dimenhydrinate (di-men-hi′dri-nat)
The 8-chlorotheophylline salt of the antihistamine, diphenhydramine; used for the prevention of motion sickness, as an antihistamine and mild sedative. Also used in the treatment of Parkinson disease, as it has appreciable anticholinergic properties.

dimension (di-men′shun)
Scope, size, magnitude; denoting, in the plural, linear measurements of length, width, and height. buccolingual d. the diameter or d. of a premolar or molar tooth from buccal to lingual surface. occlusal vertical d. the vertical d. of the face when the teeth or occlusion rims are in contact in centric occlusion; decrease in occlusal vertical d. may result from modification of tooth form by attrition or grinding, drifting of teeth, or, in edentulous patients, by resorption of residual ridges; increase may result from modifications of tooth form, tooth position, height of occlusion rims, rebasing or relining, or occlusal splints. rest vertical d. the vertical d. of the face with the jaws in rest relation; decrease in rest vertical d. may or may not accompany a decrease in occlusal vertical d.; it may occur without a decrease in occlusal vertical d. in patients with a preponderant activity of the jaw-closing musculature, as in patients with muscular hypertenseness or in chronic gum chewers; increase in rest vertical d. may or may not accompany an increase in occlusal vertical d.; it sometimes occurs after the removal of remaining occlusal contacts, perhaps as a result of the removal of noxious reflex stimuli. vertical d. a vertical measurement of the face between any two arbitrarily selected points which are conveniently located, one above and one below the mouth, usually in the midline. SYN: vertical opening.

dimer (di′mer)
A compound or unit produced by the combination of two like molecules; in the strictest sense, without loss of atoms (thus nitrogen tetroxide, N2O4, is the d. of nitrogen dioxide, NO2), but usually by elimination of H2O or a similar small molecule between the two ( e.g., a disaccharide), or by simple noncovalent association (as of two identical protein molecules); higher orders of complexity are called trimers, tetramers, oligomers, and polymers. [G. di-, two, + -mer] pyrimidine d. a product of ultraviolet radiation of pyrimidines in nucleic acids; most frequently thymidine dimers. thymine d. a product of ultraviolet irradiation of thymine (free in ice or bound in nucleic acids) in which two thymine residues become linked by formation of a cyclobutane ring involving both C-5's and both C-6's at the expense of the two double bonds; several stereoisomeric forms are possible.

dimercaprol (di-mer-kap′rol)
A chelating agent, developed as an antidote for lewisite and other arsenical poisons. It acts by competing for the metal with the essential —SH groups in the pyruvate oxidase system of the cells and forms, with arsenic, a stable, relatively nontoxic cyclic compound, the metal having a greater affinity for it than for the —SH groups of the cell proteins; also used as an antidote for antimony, bismuth, chromium, mercury, gold, and nickel. SYN: antilewisite, British anti-Lewisite.

dimercurion (di-mer′kur-i′on)
The mercuric ion, Hg2+.

dimeric (di′mer-ik)
Having the characteristics of a dimer.

dimerous (dim′er-us)
Consisting of two parts. [G. di-, two, + meros, part]

dimetacrine tartrate (di-met′a-kren)
An antidepressant.

dimethadione (di-meth-a-di′on)
The active metabolite formed by the N-demethylation of trimethadione, an oxazolidinedione type antiepileptic agent. Can be used for in vivo measurement of intracellular pH.

dimethicone (di-meth′i-kon)
A silicone oil consisting of dimethylsiloxane polymers, usually incorporated into a petrolatum base or a nongreasy preparation and used for the protection of normal skin against various, chiefly industrial, skin irritants; may also be used to prevent diaper dermatitis.

dimethindene maleate (di-meth′in-den)
An antihistamine also used as an antipruritic.

dimethisterone (di-me-this′ter-on)
A modified testosterone or ethisterone; an orally effective synthetic progestin used alone or in combination with ethynyl estradiol as a contraceptive agent.

dimethothiazine mesylate (di-meth-o-thi′a-zen)
SYN: fonazine mesylate.

dimethoxanate hydrochloride (di′me-thok′sa-nat)
A non-narcotic antitussive agent, less effective than codeine.

dimethoxyamphetamine (DMA)
A hallucinogen with properties resembling lysergic acid diethylamide (LSD).

2,5-dimethoxy-4-methylamphetamine (DOM)
An hallucinogenic agent chemically related to amphetamine and mescaline, a drug of abuse.

dimethylallylpyrophosphate (di-meth′il-al′lil-pi′ro -fos′fat)
An intermediate in steroid and terpene biosynthesis.

dimethylaminoazobenzene (di-meth′il-a-me-no-az-o-ben′zen) [C.I. 11160]
SYN: butter yellow.

dimethylarsinic acid (di-meth′il-ar-sin′ik)
SYN: cacodylic acid.

dimethylbenzene (di-meth-il-ben′zen)
SYN: xylol.

5,6-dimethylbenzimidazole (di-meth′il-benz-e-mid-a-zol)
A structural moiety found in one of the cobalamins.

dimethylcarbinol (di-meth-il-kar′bi-nol)
SYN: isopropyl alcohol.

dimethyl-1-carbomethoxy-1-propen-2-yl phosphate
An organic phosphorus compound used as a systemic poison for the extermination of such pests as mites, aphids, and houseflies.

dimethyl iminodiacetic acid (HIDA) (di-meth′il im′i-no-di-a-se-tik)
A radiopharmaceutical labeled with 99mTc, an early agent used for cholescintigraphy.

dimethyl ketone (di-meth′il ke′ton)
SYN: acetone.

dimethylmercury (di-meth-il-mer′ku-re)
A contaminant of seafood products synthesized in sediments from mercury and mercury-containing chemicals dumped in waters supporting marine life. The methylmercury is concentrated in aquatic life forms and can thus be deposited in fishes intended for human consumption. Probable cause of Minimata disease, a teratogenic condition characterized by multiple birth defects. An inorganic reagent. SEE ALSO: Minamata disease. SYN: methylmercury.


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