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Medical Dictionary


deacylase (de-as′il-as)
1. A member of the subclass of hydrolases (EC class 3), especially of that subclass of esterases, lipases, lactonases, and hydrolases (EC subclass 3.1). 2. Any enzyme catalyzing the hydrolytic cleavage of an acyl group (R&cbond;CO&cbond;) in an ester linkage; also includes enzymes cleaving amide linkages (EC subclass 3.5) and similar acyl compounds.

dead (ded)
1. Without life. SEE ALSO: death. 2. Numb.

SYN: O-diethylaminoethyl cellulose.

deaf (def)
Unable to hear. [A.S. deáf]

deafferentation (de-af′er-en-ta′shun)
A loss of the sensory input from a portion of the body, usually caused by interruption of the peripheral sensory fibers. [L. de, from, + afferent]

deafness (def′nes)
General term for inability to hear. central d. d. due to disorder of the auditory system of the brainstem or cerebral cortex. cortical d. d. resulting from bilateral lesions of the primary receptive area of the temporal lobe. hereditary d. See hereditary hearing impairment. nerve d., neural d. former terms for sensorineural hearing loss. postlingual d. hearing impairment occurring after speech and language skills have been developed. prelingual d. hearing impairment occurring before development of speech and language skills. sudden d. a profound sensory hearing loss that develops in 24 hrs or less; generally thought to be due to a viral infection in the inner ear. word d. SYN: auditory aphasia.

dealbation (de-al-ba′shun)
The act of whitening, bleaching, or blanching. [L. de-albo, pp. -atus, to whiten]

dealcoholization (de-al′ko-hol-i-za′shun)
The removal of alcohol from a fluid; in histologic technique, the removal of alcohol from a specimen that has been previously immersed in this fluid.

deallergize (de-al′er-jiz)
Obsolete term for desensitize.

deamidases (de-am′i-da-sez)
SYN: amidohydrolases.

deamidation, deamidization (de-am-i-da′shun, de-am′i-di-za′shun)
The hydrolytic removal of an amide group.

deamidize (de-am′i-diz)
To perform deamidation. SYN: desamidize.

deaminases (de-am′i-na-sez) [EC 3.5.4.x]
Enzymes catalyzing simple hydrolysis of C&cbond;NH2 bonds of purines, pyrimidines, and pterins, thus producing ammonia (usually named in terms of the substrate, e.g., guanine d., adenosine d., AMP d., pterin d.); not generally used for deamination of noncyclic amides. D. are distinguished from ammonia-lyases (EC 4.3.1.x) in that the latter produce an unsaturation at the point of NH3 removal. SYN: deaminating enzymes.

deamination, deaminization (de-am-i-na′shun, de-am′i-ni-za′shun)
Removal, usually by hydrolysis, of the NH2 group from an amino compound. oxidative d. d. by enzymes that uses flavin or pyridine nucleotides (such as FAD or NAD+).

deaminize (de-am′i-niz)
To perform deamination.

Henry Trendley, U.S. dentist and epidemiologist, 1893–1962. See D. fluorosis index.

deanol acetamidobenzoate (de′a-nol as-e-tam′i-do-ben′zo-at)
The p-acetamidobenzoic acid salt of 2-dimethylaminoethanol; a central nervous system stimulant.

death (deth)
The cessation of life. In lower multicellular organisms, d. is a gradual process at the cellular level, because tissues vary in their ability to withstand deprivation of oxygen; in higher organisms, a cessation of integrated tissue and organ functions; in humans, manifested by the loss of heartbeat, by the absence of spontaneous breathing, and by cerebral d.. SYN: mors. [A.S. d.] black d. term applied to the worldwide epidemic of the 14th century, of which some 60 million persons are said to have died; the descriptions indicate that it was pneumonic plague. brain d. SYN: cerebral d.. cerebral d. a clinical syndrome characterized by the permanent loss of cerebral and brainstem function, manifested by absence of responsiveness to external stimuli, absence of cephalic reflexes, and apnea. An isoelectric electroencephalogram for at least 30 minutes in the absence of hypothermia and poisoning by central nervous system depressants supports the diagnosis. SYN: brain d.. d. certificate official, legal document and vital record, signed by a licensed physician or other designated authority, that includes cause of d., decedent's name, sex, place of residence, date of d.; other information, e.g., birth date, birth place, occupation may be included; the immediate cause of d. is recorded on the first line of the certificate, followed by the condition(s) giving rise to this, with the underlying cause on the last line; the underlying cause is coded and tabulated in official publications of mortality. cot d. SYN: sudden infant d. syndrome. crib d. SYN: sudden infant d. syndrome. crude d. rate SYN: d. rate. fetal d. d. prior to the complete expulsion or extraction from the mother of a product of conception, irrespective of the duration of pregnancy. Fetal d. is considered early if it takes place in the first 20 weeks of gestation; middle (intermediate) if it takes place from 21–28 weeks of gestation, and late if it takes place after 28 weeks. genetic d. d. of the bearer of a gene at any age before generating living offspring. May be compatible with good health and long life. SEE ALSO: genetic lethal. infant d. d. of a liveborn infant within the first year. local d. d. of a part of the body or of a tissue by necrosis. maternal d. d. of a woman while pregnant or within 42 days after the termination of gestation, irrespective of the duration and site of pregnancy and the cause of d.; two periods are recognized in the 42-day interval: period one includes day 1 to day 7; period two includes day 8 to day 42. Maternal deaths are further classified as: direct maternal d., d. resulting from obstetric complications of the gestation, labor, or puerperium, and from interventions, omissions, incorrect treatment, or a chain of events caused by any of the above; indirect maternal d., an obstetric d. resulting from previously existing disease or from disease developing during pregnancy, labor, or the puerperium; it is not directly due to obstetric causes, but to conditions aggravated by the physiologic effects of pregnancy. neonatal d. d. of a young, liveborn infant; classified as: early neonatal d., d. of a liveborn infant occurring fewer than 7 completed days (168 hours) from the time of birth; late neonatal d., d. of a liveborn infant occurring after 7 completed days of age but before 28 completed days. perinatal d. an inclusive term referring to both stillborn infants and neonatal deaths. programmed cell d. SYN: apoptosis. somatic d., systemic d. d. of the entire body, as distinguished from local d.. sudden d. d. occurring rapidly and generally unexpectedly; usually from a cardiac dysrhythmia or myocardial infarction, but also from any cause of rapid d., e.g., pulmonary embolus, stroke, ruptured aortic aneurysm, aortic dissection.

death-rattle (deth′rat′l)
A respiratory gurgling or rattling in the pharynx or trachea of a dying person, caused by the loss of the cough reflex and accumulation of mucus.

John Blair, U.S. surgeon, 1855–1931. See D. incision.

George G., U.S. physiatrist, 1890–1973. See D. method.

Michael Ellis, U.S. heart surgeon, *1908. See D. classification, D. forceps.

debanding (de-band′ing)
The removal of fixed orthodontic appliances.

debilitant (de-bil′i-tant)
1. Weakening; causing debility. 2. Obsolete term for a quieting agent or one that subdues excitement. [L. debilito, to weaken, fr. de, neg., + habilis, able]

debilitating (de-bil′i-tat-ing)
Denoting or characteristic of a morbid process that causes weakness.

debility (de-bil′i-te)
Weakness. [L. debilitas, fr. debilis, weak, fr. de- priv. + habilis, able]

debond (de-bond′)
To separate a dental appliance such as an orthodontic band from the tooth to which it has been attached or bonded by a resin cement. [de- + bond]

debouch (de-boosh′)
To open or empty into another part. [Fr. bouche, mouth]

débouchement (da-boosh-mon′)
Opening or emptying into another part. [Fr.]

Robert, French pediatrician and infectious disease specialist, 1882–1978. See Debré phenomenon, Debré-Sémélaigne syndrome, Kocher-Debré-Sémélaigne syndrome.

débridement (da-bred-mon′)
Excision of devitalized tissue and foreign matter from a wound. [Fr. unbridle]

debris (de-bre)
A useless accumulation of miscellaneous particles; waste in the form of fragments. [Fr. débris, fr. O.Fr. desbrisier, to break apart, (fr. des- down, away + brisier to break) rubble, rubbish] particulate wear d. microscopic particles produced by friction between articulating surfaces in a total joint replacement; d. can include particles of metal, polyethylene, and polymethylmethacrylate cement, and can induce osteolysis.

debrisoquine sulfate (de-bris′o-kwin)
An antihypertensive agent resembling guanethidine; also used in drug metabolism studies.

debt (det)
A deficit; a liability. [L. debitum, d.] alactic oxygen d. that part of the oxygen d. that is not lactacid oxygen d.; during recovery, stores of ATP and creatine phosphate must be replenished by oxidative metabolism, and a small amount of oxygen is also needed to restore the normal oxyhemoglobin levels throughout the circulating blood. lactacid oxygen d. that part of an oxygen d. represented by the production of lactic acid by anaerobic glycolysis during exercise and, therefore, by the need to eliminate it by oxidative metabolism during recovery. oxygen d. the extra oxygen, taken in by the body during recovery from exercise, beyond the resting needs of the body; sometimes used as if synonymous with oxygen deficit.

deca- (da)
Prefix used in the SI and metric system to signify multiples of 10. Also spelled deka-. [G. deka, ten]

decagram (dek′a-gram)
Ten grams.

decalcification (de′kal-si-fi-ka′shun)
1. Removal of lime or calcium salts, chiefly tricalcium phosphate, from bones and teeth, either in vitro or in vivo as a result of a pathologic process. 2. Precipitation of calcium from blood as by oxalate or fluoride, or the conversion of blood calcium to an un-ionized form as by citrate, thus preventing or delaying coagulation. [L. de-, away, + calx (calc-), lime, + facio, to make]

decalcify (de-kal′si-fi)
To remove lime or calcium salts, especially from bones or teeth.

decalcifying (de-kal′si-fi-ing)
Denoting an agent, measure, or process that causes decalcification.

decaliter (dek′a-le-ter)
Ten liters.

decalvant (de-kal′vant)
Removing the hair; making bald. [L. decalvare, to make bald]

decameter (dek′a-me-ter)
Ten meters.

decamethonium bromide (dek-a-me-tho′ne-um)
A synthetic nondepolarizing neuromuscular blocking agent used to produce muscular relaxation during general anesthesia.

decamine (dek′a-men)
SYN: dequalinium acetate.

decannulation (de-kan-u-la′shun)
Planned or accidental removal of a tracheostomy tube.

decanoin (dek-a-no′in)
SYN: caprin.

decanormal (dek-a-nor′mal)
Rarely used term denoting the concentration of a solution 10 times that of normal.

decant (de-kant′)
To pour off gently the upper clear portion of a fluid, leaving the sediment in the vessel. [Mediev. L. decantho, fr. de- + canthus, the beak of a jug, fr. G. kanthos, corner of the eye]

decantation (de-kan-ta′shun)
Pouring off the clear upper portion of a fluid, leaving a sediment or precipitate.

decapacitation (de′ka-pas-i-ta′shun)
Prevention of spermatozoa from undergoing capacitation and thus from becoming able to fertilize ova. SEE ALSO: d. factor.

decapeptide (dek′a-pep′tid)
An oligopeptide containing 10 amino acids.

decapitate (de-kap′i-tat)
1. To cut off the head; specifically, to remove the head of a fetus to facilitate delivery in cases of irremediable dystocia; to cut off the head of an animal in preparation for certain physiologic experiments; obsolete term. 2. Relating to an experimental animal with the head removed. [L. de-, away, + caput, head]

decapitation (de-kap-i-ta′shun)
Removal of a head. See decapitate.

decapsulation (de-kap-soo-la′shun)
Incision and removal of a capsule or enveloping membrane. d. of kidney removing or stripping off the capsule of the kidney.

decarbonization (de-kar′bon-i-za′shun)
Rarely used term denoting the process of arterialization of the blood by oxygenation and the removal of carbon dioxide in the lungs.

decarboxylase (de-kar-boks′e-las)
Any enzyme (EC 4.1.1.x) that removes a molecule of carbon dioxide from a carboxylic group ( e.g., from an α-amino acid, converting it into an amine).

decarboxylation (de′kar-boks-e-la′shun)
A reaction involving the removal of a molecule of carbon dioxide from a carboxylic acid. oxidative d. d. requiring the participation of coenzymes such as NAD+, NADP+, FAD, or FMN.

decay (de-ka′)
1. Destruction of an organic substance by slow combustion or gradual oxidation. 2. SYN: putrefaction. 3. To deteriorate; to undergo slow combustion or putrefaction. 4. In dentistry, caries. 5. In psychology, loss of information registered by the senses and processed into short-term memory. SEE ALSO: memory. 6. Loss of radioactivity with time; spontaneous emission of radiation or charged particles or both from an unstable nucleus. [L. de, down, + cado, to fall] free induction d. (FID) in magnetic resonance imaging, the d. curve that is detected by the receiver coil after the application of an excitation pulse, without additional pulses.

deceleration (de-sel-er-a′shun)
1. The act of decelerating. 2. The rate of decrease in velocity per unit of time. early d. slowing of the fetal heart rate early in the uterine contraction phase, denoting compression of the fetal head. late d. any transient fetal bradycardia, the nadir of which occurs after the peak of the uterine contraction. This may represent uteroplacental insufficiency. variable d. transient fetal bradycardia usually denoting compression of the umbilical cord, which may occur at any time in relation to a uterine contraction.

decentration (de-sen-tra′shun)
Removal from the center.

decerebrate (de-ser′e-brat)
1. To cause decerebration. 2. Denoting an animal so prepared, or a patient whose brain has suffered an injury which renders the patient, in neurologic behavior, comparable to a d. animal.

decerebration (de-ser′e-bra′shun)
Removal of the brain above the lower border of the corpora quadrigemina, or a complete section of the brain at this level or somewhat below. bloodless d. destroying the function of the cerebrum by tying the basilar artery at about the middle of the pons and the common carotid arteries in the neck.

decerebrize (de-ser′e-briz)
To remove the brain.

dechloridation (de′klor-i-da′shun)
Reduction of sodium chloride in the tissues and fluids of the body by reducing its intake or increasing its excretion. SYN: dechlorination, dechloruration.

dechlorination (de′klor-i-na′shun)
SYN: dechloridation.

dechloruration (de′klor-oo-ra′shun)
SYN: dechloridation.


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