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Medical Dictionary


dideoxyinosine (DDI) (di′-de-oks-e-i′-no-sen)
Antiviral agent; has been used in treatment of AIDS.

An acronym for Wolfram syndrome, which comprises diabetes insipidus, diabetes mellitus, optic atrophy, and deafness.

didym-, didymo-
The didymus, testis. [G. didymos, twin]

didymus (did′e-mus)
SYN: testis. [G. didymos, a twin, pl. didymoi, testes]

A conjoined twin, with the first element of the complete word designating fused parts. SEE ALSO: -dymus, -pagus. [G. didymos, twin]

die (di)
In dentistry, the positive reproduction of the form of a prepared tooth in any suitable hard substance, usually in metal or specially prepared artificial stone. SEE ALSO: counterdie.

dieb. alt.
Abbreviation for L. diebus alternis, every other day.

diecious (di-e′shus)
Denoting animals or plants that are sexually distinct, the individuals being of one or the other sex. [G. di-, two, + oikia, house]

Johann F., German surgeon, 1792–1847.

Diego blood group, Di blood group
See Blood Groups appendix.

diel (di′el)
Term frequently used synonymously with diurnal (2) or circadian. [irreg., fr. L. dies, day]

dieldrin (di-el′drin)
A chlorinated hydrocarbon used as an insecticide; may cause toxic effects in persons and animals exposed to its action through skin contact, inhalation, or food contamination.

dielectrography (di-e-lek-trog′ra-fe)
SYN: impedance plethysmography.

dielectrolysis (di′e-lek-trol′i-sis)
SYN: electrophoresis.

Otto, German chemist and Nobel laureate, 1876–1954. See D. hydrocarbon.

diencephalohypophysial (di-en-sef′a-lo-hi-po-fiz′e-al)
Relating to the diencephalon and hypophysis.

diencephalon, pl .diencephala (di-en-sef′a-lon, -sef′a-la) [TA]
The caudal part of the prosencephalon composed of the epithalamus, thalamus, and hypothalamus. [G. dia, through, + enkephalos, brain]

diener (de′ner)
A laboratory worker who assists in cleaning; most commonly applied to laboratory workers who assist in the performance of autopsies and maintenance of morgues. [Ger. D., servant]

dienestrol (di-en-es′trol)
An estrogenic agent. SYN: estrodienol.

Dientamoeba fragilis (di-ent-a-me′ba fraj′i-lis)
A species of small amebalike flagellates, formerly considered a true ameba, now recognized as an ameboflagellate related to Trichomonas, parasitic in the large intestine of humans and certain monkeys; may be nonpathogenic, but believed to be capable of sometimes causing low-grade inflammation with mucous diarrhea and gastrointestinal disturbance in humans.

dieresis (di-er′e-sis)
SYN: solution of continuity. [G. diairesis, a division]

dieretic (di-er-et′ik)
1. Relating to dieresis. 2. Dividing; ulcerating; corroding.

diesterase (di-es′ter-as)
See phosphodiesterases.

diestrous (di-es′trus)
Pertaining to diestrus.

diestrus (di-es′trus)
A period of sexual quiescence intervening between two periods of estrus. [G. dia, between, + oistros, desire]

diet (di′et)
1. Food and drink in general. 2. A prescribed course of eating and drinking in which the amount and kind of food, as well as the times at which it is to be taken, are regulated for therapeutic purposes. 3. Reduction of caloric intake so as to lose weight. 4. To follow any prescribed or specific d.. [G. diaita, a way of life; a d.] acid-ash d. SYN: alkaline-ash d.. alkaline-ash d. a d. consisting mainly of fruits, vegetables, and milk (with minimal amounts of meat, fish, eggs, cheese, and cereals), which, when catabolized, leave an alkaline residue to be excreted in the urine. SYN: acid-ash d., basic d.. balanced d. a d. containing the essential nutrients with a reasonable ration of all the major food groups. basal d. 1. a d. having a caloric value equal to the basal heat production and sufficient quanties of essential nutrients to meet basic needs; 2. in experiments in nutrition, a d. complete and adequate except for a single constituent ( e.g., a vitamin, mineral, or amino acid), the nutritional value of which is to be determined, is omitted for a period and the effects observed; the subject is observed for a second period during which the ingredient being studied is added to the d.. basic d. SYN: alkaline-ash d.. bland d. a regular d. omitting foods that mechanically or chemically irritate the gastrointestinal tract. BRAT d. a limited d. often used in regimens for acute gastroenteritides; acronym for bananas, rice, apples (juice or sauce), and toast. challenge d. a d. in which one or more specific substances are included for the purpose of determining whether an abnormal reaction occurs. clear liquid d. a d., often used postoperatively, consisting usually of water, tea, coffee, gelatin preparations, and clear soups or broth. diabetic d. a dietary adjustment for patients with diabetes mellitus intended to decrease the need for insulin or oral diabetic agents and control weight by adjusting caloric and carbohydrate intake. elimination d. a d. designed to detect what ingredient of the food causes allergic manifestations in the patient; food items to which the patient may be sensitive are withdrawn separately and successively from the d. until that which causes the symptoms is discovered. full liquid d. a d. consisting only of liquids but including cream soups, ice cream, and milk. Giordano-Giovannetti d. a d. designed for patients with renal failure; it provides small amounts of protein, primarily as essential amino acids, along with alpha-keto derivatives of amino acids; breakdown of protein in skeletal muscle is retarded and, because transaminase reactions are reversible, a small proportion of the ammonia released by urea breakdown is used for synthesis of nonessential amino acids. SYN: Giovannetti d.. Giovannetti d. SYN: Giordano-Giovannetti d.. gluten-free d. elimination of all wheat, rye, barley, and oat gluten from the d.; treatment for gluten-sensitive enteropathy (celiac disease). See celiac disease. gout d. a d. containing a minimal quantity of purine bases (meats); liver, kidney, and sweetbread especially are excluded and replaced by dairy products, fruits, and cereals; alcoholic beverages also are excluded. SYN: purine-free d.. high-calorie d. a d. containing upward of 4,000 calories per day. high-fat d. a d. containing large amounts of fat. high-fiber d. a d. high in the nondigestible part of plants, which is fiber. Fiber is found in fruits, vegetables, whole grains, and legumes. Insoluble fiber increases stool bulk, decreases transit time of food in the bowel, and decreases constipation and the risk of colon cancer. Soluble fiber delays absorption of glucose, which helps to control blood sugar in diabetes mellitus, and delays absorption of lipids, which helps to control hyperlipidemia. Recommended in treatment of diverticular disease of the colon. Kempner d. SYN: rice d.. ketogenic d. a high-fat, low-carbohydrate, and normal protein d. causing ketosis. low-calorie d. a d. of 1,200 calories or less per day. low-fat d. a d. containing a minimal proportion of fat.Diets containing low amounts of fat and cholesterol are designed to reduce the risk of cardiovascular disease, specifically atherosclerosis. The National Cholesterol Education Program recommends maintaining a total cholesterol level of no more than 200 mg/dL, with LDL cholesterol less than 130 mg/dL and HDL cholesterol at least 60 mg/dL. (According to the National Institutes of Health, LDL cholesterol in patients with atherosclerotic heart disease should not exceed 100 mg/dL.) About one-half of adult Americans exceed these total cholesterol and LDL cholesterol limits; for many, the reason is an inborn metabolic disorder of lipid metabolism not correctable by dietary restrictions alone. A low-fat d. should derive less than 10% of its calories from saturated fat (meats, dairy products) and should be low in cholesterol (<300 mg/d) and trans fatty acids (e.g., hydrogenated oils as in stick margarine and shortening) and rich in whole grains, fresh fruits and vegetables, and legumes. People who follow an extremely low-fat d. experience some reversal in atherosclerosis despite a concomitant decrease in HDL cholesterol. A low-fat d. may also help decrease body weight or prevent weight gain, because fats and oils yield more than twice as many calories per gram as carbohydrate and protein foods. See atherosclerosis; free radical. low purine d. a d. low in precursors of purines (such as tissues rich in cells with abundant nuclei, as in liver, glandular meats, etc.) to minimize formation of uric acid. Useful in treatment of patients with gout or urate-containing renal calculi. low residue d. a d. that leaves minimal unabsorbed components in the intestine, to minimize functional stress on the colon. low salt d. a d. with restricted amounts of sodium chloride, useful in the treatment of some cases of hypertension, heart failure, and other syndromes characterized by fluid retention and/or edema formation. macrobiotic d. a d. claimed to promote longevity, often by promoting an emphasis on natural foods and restrictions on noncereal foods, as well as liquids. Meulengracht d. a feeding program for patients with peptic ulcer disease, containing a relatively full d. free of acidic or highly seasoned food. Minot-Murphy d. the use of large amounts of raw liver in the treatment of pernicious anemia. First successes in the treatment of this disease occurred with this d. and led to development of liver extract for treatment. Ornish prevention diets relaxed versions of the Ornish reversal d., which is designed to prevent coronary artery disease. These diets reduce dietary fat in proportion to blood cholesterol level. Ornish reversal d. a d. designed by Dean Ornish, who has evidence that it will reverse coronary artery disease. It consists of 10% of calories from fat (mostly polyunsaturated or monounsaturated, with 5 mg cholesterol per day), 70–75% from carbohydrate, and 15–20% from protein. purine-free d. SYN: gout d.. purine-restricted d. gout d.. rachitic d. a d. that will induce rickets in susceptible experimental animals. reducing d. a d. in which caloric expenditure is greater than caloric intake. rice d. a d. of rice, fruit, and sugar, plus vitamin and iron supplements, devised by Kempner to treat hypertension. In 2,000 calories, the d. contains 5 gm or less of fat, about 20 gm of protein, and not more than 150 mg of sodium. SYN: Kempner d.. Schmidt d. SYN: Schmidt-Strassburger d.. Schmidt-Strassburger d. an obsolete d. designed to facilitate examination of the stools in patients with diarrhea, consisting of milk, zwieback, oatmeal gruel, eggs, butter, small amounts of beef and potato. SYN: Schmidt d.. Sippy d. a d. formerly used in the initial stages of treatment of peptic ulcer, beginning with milk and cream every hour or two to keep gastric acid neutralized, gradually increasing to include cereal, eggs and crackers after three days, pureed vegetables later. smooth d. a d. containing little roughage; used primarily in diseases of the colon. soft d. a normal d. limited to soft foods for those who have difficulty chewing or swallowing; there are no restrictions on seasoning or method of food preparation. subsistence d. a meager d. providing barely enough for sustenance. Wilder d. obsolete d., low in potassium, for treating Addison disease.

dietary (di′e-tar-e)
Relating to the diet.

Dieterle stain
See under stain.

dietetic (di′e-tet′ik)
1. Relating to the diet. 2. Descriptive of food that, naturally or through processing, has a low caloric content.

dietetics (di-e-tet′iks)
The practical application of diet in the prophylaxis and treatment of disease.

diethadione (di-eth-a-di′on)
An analeptic.

diethanolamine (di-eth-a-nol′a-men)
Used as an emulsifier and as a dispersing agent in cosmetics and pharmaceuticals. SYN: diethylolamine.

diethazine (di-eth′a-zen)
An anticholinergic agent.

diethyl (di-eth′il)
A compound containing two ethyl radicals.

5,5-diethylbarbituric acid (di-eth′il-bar-bi-tu′rik)
SYN: barbital.

diethylcarbamazine citrate (di-eth′il-kar-bam′a-zen)
An effective microfilaricide, although relatively ineffective against the adult filariae.

diethylenediamine (di-eth′il-en-di′a-men)
SYN: piperazine.

1,4-diethylene dioxide (di-eth′il-en)
SYN: dioxane.

diethylene glycol (di-eth′il-en)
An organic solvent chemically related to ethylene glycol. Upon metabolic conversion it becomes oxalic acid, which is toxic to the kidney. A sweet, viscous liquid that was used to make the infamous elixir of sulfanilamide that proved fatal to over 100 children in 1937, leading to the mandate to the FDA to monitor drug safety.

diethylenetriamine pentaacetic acid (DTPA) (di-eth′il-en-tri′a-men pen-ta-a-se′tik as′id)
An important chelating agent used in therapy ( e.g., in therapy for lead poisoning), and in metal-containing diagnostic agents for magnetic resonance imaging and nuclear scanning.

diethyl ether
A flammable, volatile organic solvent formerly widely used in surgical procedures; was used as an inhalation anesthetic; shortcomings include: irritating vapor, slow onset and prolonged recovery phase, explosion hazard. SYN: ethyl ether, ethyl oxide, sulfuric ether.

diethylolamine (di-eth-i-lol′a-men)
SYN: diethanolamine.

diethylpropion hydrochloride (di-eth-il-pro′pe-on)
A sympathomimetic drug resembling amphetamine in its actions and used as an appetite suppressant. Increases blood pressure, heart rate.

diethylstilbestrol (DES) (di-eth′il-stil-bes′trol)
A synthetic nonsteroidal estrogenic compound. Sometimes used as a postcoital antipregnancy agent to prevent implantation of the fertilized ovum. The first demonstrated transplacental carcinogen responsible for a delayed clear cell vaginal carcinoma in female offspring of mothers who took the drug during pregnancy when the drug was erroneously thought to prevent threatened abortion. SYN: stilbestrol.

diethyltoluamide (di-eth′il-to-loo′a-mid)
An insect repellent.

diethyltryptamine (DET) (di-eth-il-trip′ta-men)
A hallucinogenic agent similar to dimethyltryptamine.

dietitian (di-e-tish′un)
An expert in dietetics.

Józef, Polish physician, 1804–1878. See D. crisis.

Dieuaide diagram
See under diagram.

Georges, French physician, 1839–1911. See D. erosion.

difarnesyl group (di-far′ne-sil)
A 30-carbon open chain hexaisoprenoid hydrocarbon radical; occurs as a side chain in vitamin K2.

difenoxin (di-fen-ok′sin)
An antidiarrheal agent with actions similar to those of diphenoxylate. SYN: difenoxylic acid.

difenoxylic acid (di-fen-ok′si-lik)
SYN: difenoxin.

difference (dif′er-ens)
The magnitude or degree by which one quality or quantity differs from another of the same kind. alveolar-arterial oxygen d. the d. or gradient between the partial pressure of oxygen in the alveolar spaces and the arterial blood: P(A–a)02. Normally in young adults this value is less than 20 mm Hg. SEE ALSO: alveolar gas equation. arteriovenous carbon dioxide d. the d. in carbon dioxide content (in mL per 100 mL blood) between arterial and venous blood. arteriovenous oxygen d. the d. in the oxygen content (in mL per 100 mL blood) between arterial and venous blood. AV d. abbreviation for arteriovenous d. of concentration of a substance. cation-anion d. SYN: anion gap. individual differences in clinical psychology, deviations of individuals from the group average or from each other. light d. 1. the d. in light sensitivity of the two eyes; 2. SYN: brightness d. threshold. masking level d. a technique of comparing threshold responses with masking noise presented in phase and out of phase with the test signal; release from masking is normal and indicates an intact brainstem auditory pathway. standard error of d. a statistical index of the probability that a d. between two sample means is greater than zero.

differential (dif-er-en′shal)
Relating to, or characterized by, a difference; distinguishing. [L. dif-fero, to carry apart, differ, fr. dis, apart] threshold d. SYN: d. threshold.

differentiated (dif-er-en′she-a-ted)
Having a different character or function from the surrounding structures or from the original type; said of tissues, cells, or portions of the cytoplasm.

differentiation (dif′er-en-she-a′shun)
1. The acquisition or possession of one or more characteristics or functions different from that of the original type. SYN: specialization (2) . 2. SYN: differential diagnosis. 3. Partial removal of a stain from a histologic section to accentuate the staining differences of tissue components. correlative d. d. due to the interaction of different parts of an organism. echocardiographic d. the processing of a signal so that the output depends upon the rate of change of the input; e.g., it will display changes in amplitude but will reduce the duration of the waveform. invisible d. SYN: chemodifferentiation. pressure pulse d. the processing of a pressure pulse signal so that the output depends upon the rate of change of the input, yielding dP/dt (pressure) or, for noninvasively recorded pulses, dD/dt (rate of change of displacement).

diffluence (dif′loo-ens)
The process of becoming fluid. [L. dif-fluo, to flow in different directions, dissolve]

diffraction (di-frak′shun)
Deflection of the rays of light from a straight line in passing by the edge of an opaque body or in passing an obstacle of about the size of the wavelength of the light. [L. dif- fringo, pp. -fractus, to break in pieces]

diffraction grating
A variety of filter composed of lined grooves in a thin layer of aluminum-copper alloy on a glass surface; used in spectrophotometers to disperse light into a spectrum. See monochromator.

diffusate (di-fu′zat)
SYN: dialysate. [L. dif-fundo, pp. -fusus, to pour in different directions]

diffuse (di-fus)
1. (di-fuz′)To disseminate; to spread about. 2. (di-fus′)Disseminated; spread about; not restricted. [L. dif-fundo, pp. -fusus, to pour in different directions]

diffusible (di-fuz′i-bl)
Capable of diffusing.

diffusion (di-fu′zhun)
1. The random movement of molecules or ions or small particles in solution or suspension under the influence of brownian (thermal) motion toward a uniform distribution throughout the available volume; the rate is relatively rapid among liquids and gases, but takes place very slowly among solids. 2. Light scattering. facilitated d. See facilitated transport. gel d. d. in a gel, as in the case of gel d. precipitin tests in which the immune reactants diffuse in agar. SEE ALSO: immunodiffusion. passive d. See facilitated transport.

diflorasone diacetate (di-flor′a-son)
An anti-inflammatory corticosteroid used in topical preparations.

diflucortolone (di-floo-kor′ti-lon)
A synthetic glucocorticoid steroid analog.


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