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Medical Dictionary


demilune (dem′e-loon)
1. A small body with a form similar to that of a half-moon or a crescent. 2. Term frequently used for the gametocyte of Plasmodium falciparum. [Fr. half-moon] Giannuzzi demilunes SYN: serous demilunes. Heidenhain demilunes SYN: serous demilunes. serous demilunes the serous cells at the distal end of a mucous, tubuloalveolar secretory unit of certain salivary glands. SYN: Giannuzzi crescents, Giannuzzi demilunes, Heidenhain crescents, Heidenhain demilunes.

demineralization (de-min′er-al-i-za′shun)
A loss or decrease of the mineral constituents of the body or individual tissues, especially of bone.

demipenniform (dem′e-pen′i-form)
SYN: semipennate.

Demodex (dem′o-deks)
A genus of very minute (0.1–0.4 mm) follicular mites (family Demodicidae) that inhabit the skin and are usually found in the sebaceous glands and hair follicles of mammals, including humans. Some cases of blepharitis in humans have been attributed to D. infection; use of facial creams promotes D. infection in older women, resulting in facial erythema with follicular scaling. [G. demos, tallow, + dex, a woodworm] D. folliculorum a very common, universally distributed, and usually nonpathogenic species of mite that inhabits the hair follicles and sebaceous glands of humans, commonly of the face around the nose and scalp margins. SYN: Acarus folliculorum.

demography (de-mog′ra-fe)
The study of populations, especially with reference to size, density, fertility, mortality, growth rate, age distribution, migration, and vital statistics. [G. demos, people, + grapho, to write] dynamic d. a study of the functioning of a community, including statistical records.

Abraham, English mathematician, 1667–1754. See D. formula.

demoniac (de-mo′ne-ak)
Frenzied, fiendish, as if possessed by evil spirits. [G. daimon, a spirit]

demonstrator (dem′on-stra-ter, -tor)
An assistant to a professor of anatomy, surgery, etc., who prepares for the lecture by dissections or collection of patients, or who instructs small classes supplementary to the regular lectures; a d. corresponds in a general way to the Dozent of a German university. [L. de-monstro, pp. -atus, to point out]

De Morgan
Campbell, English physician, 1811–1876. See D. spots, under spot.

demorphinization (de-mor′fin-i-za′shun)
1. Removal of morphine from an opiate. 2. Gradual withdrawal of morphine as a method of overcoming morphine dependence.

de Morsier
Georges, 20th century Swiss neurologist. See de Morsier syndrome.

demucosation (de-mu-ko-sa′shun)
Rarely used term for excision or stripping of the mucosa of any part.

demulcent (de-mul′sent)
1. Soothing; relieving irritation. 2. An agent, such as a mucilage or oil, that soothes and relieves irritation, especially of the mucous surfaces. [L. de-mulceo, pp. -mulctus, to stroke lightly, to soften]

de Musset
Alfred. See Musset.

demyelination, demyelinization (de-mi′e-li-na′shun, de-mi′e-lin-i-za′shun)
Loss of myelin with preservation of the axons or fiber tracts. Central d. occurs within the central nervous system ( e.g., the d. seen with multiple sclerosis); peripheral d. affects the peripheral nervous system ( e.g., the d. seen with Guillain-Barré syndrome).

denarcotize (de-nar′ko-tiz)
To remove narcotic properties from an opiate; to deprive of narcotic properties.

denatonium benzoate (de-na-to′ne-um)
An alcohol denaturant.

denaturation (de-na-tu-ra′shun)
The process of becoming denatured.

denatured (de-na′turd)
1. Made unnatural or changed from the normal in any of its characteristics; often applied to proteins or nucleic acids heated or otherwise treated to the point where tertiary structural characteristics are altered. 2. Adulterated, as by addition of methanol to ethanol.

dendriform (den′dri-form)
Tree-shaped, or branching. SYN: arborescent, dendritic (1) , dendroid. [G. dendron, tree, + L. forma, form]

dendrite (den′drit)
1. One of the two types of branching protoplasmic processes of the nerve cell (the other being the axon). SYN: dendritic process, dendron, neurodendrite, neurodendron. 2. A crystalline treelike structure formed during the freezing of an alloy. [G. dendrites, relating to a tree] apical d. SYN: apical process.

dendritic (den-drit′ik)
1. SYN: dendriform. 2. Relating to the dendrites of nerve cells.

dendrogram (den′dro-gram)
A treelike figure used to represent graphically a hierarchy. [dendron, tree, + gramma, a drawing]

dendroid (den′droyd)
SYN: dendriform. [G. dendron, tree, + eidos, appearance]

SYN: dendrite (1) . [G. a tree]

denervate (de-ner′vat)
To cause denervation.

denervation (de-ner-va′shun)
Loss of nerve supply.

dengue (den′ga)
A disease of tropical and subtropical regions that occurs epidemically, is caused by d. virus, a member of the family Flaviviridae. There are 4 antigenic types, and they are transmitted by a mosquito of the genus Aedes (usually A. aegypti, but frequently A. albopictus). Four grades of severity are recognized: grade I, fever and constitutional symptoms; grade II, grade I plus spontaneous bleeding (of skin, gums, or gastrointestinal tract); grade III, grade II plus agitation and circulatory failure; grade IV, profound shock. SYN: Aden fever, bouquet fever, breakbone fever, dandy fever, date fever, d. fever, d. hemorrhagic fever, exanthesis arthrosia, polka fever, scarlatina rheumatica, solar fever (1) . [Sp. corruption of “dandy” fever] hemorrhagic d. a more severe form of d. characterized by hemorrhagic skin lesions, which has erupted in a number of epidemic outbreaks in the Pacific basin.

denial (de-ni′al)
An unconscious defense mechanism used to allay anxiety by denying the existence of important conflicts, troublesome impulses, events, actions, or illness. SYN: negation. [M.E., fr, O.Fr., fr. L. denegare, to say no]

denidation (den-i-da′shun)
Exfoliation of the superficial portion of the mucous membrane of the uterus; stripping off of the menstrual decidua. [L. de, from, + nidus, nest]

denitration (de-ni-tra′shun)
SYN: denitrification.

denitrification (de-ni′tri-fi-ka′shun)
1. Removal of nitrogen from any material or chemical compound; especially from the soil, as by certain (denitrifying) bacteria that render the nitrogen unavailable for plant growth. 2. Withdrawal of nitrogen from soil by plant growth. SYN: denitration.

denitrify (de-ni′tri-fi)
To remove nitrogen from any material or chemical compound.

denitrogenation (de-ni′tro-je-na′shun)
Elimination of nitrogen from lungs and body tissues by breathing gases devoid of nitrogen.

Charles Clayton, U.S. dermatologist, 1883–1971. See D.-Morgan fold, D. line.

denominator (de-nom′i-na-tor)
The lower portion of a fraction used to calculate a rate or ratio; the population at risk in the calculation of a rate or ratio.

Charles P., French surgeon, 1808–1872. See D. aponeurosis, D. ligament.

de novo (di-no′vo)
Anew; often applied to particular biochemical pathways in which metabolites are newly biosynthesized ( e.g., d. purine biosynthesis). [L.]

dens, pl .dentes (denz, den′tez) [TA]
1. SYN: tooth. 2. A strong toothlike process projecting upward from the body of the axis, or epistropheus, around which the atlas rotates. SYN: d. axis [TA] , odontoid process of epistropheus, odontoid process. [L.] dentes acustici [TA] SYN: acoustic teeth. d. angularis SYN: canine tooth. d. axis [TA] SYN: d. (2) . d. bicuspidus, pl .dentes bicuspidi SYN: premolar tooth. d. caninus, pl .dentes canini [TA] SYN: canine tooth. d. cuspidatus, pl .dentes cuspidati SYN: canine tooth. d. deciduus, pl .dentes decidui [TA] SYN: deciduous tooth. d. in dente a developmental disturbance in tooth formation resulting from invagination of the epithelium associated with crown development into the area destined to become pulp space; after calcification there is an invagination of enamel and dentin into the pulp space, giving the radiographic appearance of a “tooth within a tooth.” SYN: d. invaginatus. d. incisivus, pl .dentes incisivi [TA] SYN: incisor tooth. d. invaginatus (denz in′va-ge-na′-tus) SYN: d. in dente. [Mediev. L. folded inward, fr. L. vagina, sheath] d. lacteus SYN: deciduous tooth. d. molaris, pl .dentes molares [TA] SYN: molar tooth. SEE ALSO: molar. d. molaris tertius [TA] SYN: third-year molar tooth. d. permanens, pl .dentes permanentes [TA] SYN: permanent tooth. d. premolaris, pl .dentes premolares [TA] SYN: premolar tooth. d. sapientiae SYN: third-year molar tooth. [L. sapientia, wisdom] d. serotinus third-year molar tooth. d. succedaneus SYN: permanent tooth.

densimeter (den-sim′e-ter)
SYN: densitometer (1) . [L. densitas, density, + G. metron, measure]

densitometer (den-si-tom′e-ter)
1. An instrument for measuring the density of a fluid. SYN: densimeter. 2. An instrument for measuring, by virtue of relative turbidity, the growth of bacteria in broth; useful in microbiologic assay of nutrients and antibiotics, phage studies, etc. 3. An instrument for measuring the density of components ( e.g., protein fractions) separated by electrophoresis or chromatography, utilizing light absorption or reflection. 4. An electronic instrument for measuring the blackening of radiographic film by x-ray exposure; used for film sensitometry, bone densitometry, measurement of line spread function (microdensitometer). 5. An instrument for measuring the extent to which a material absorbs or reflects light. [L. densitas, density, + G. metron, measure]

densitometry (den-si-tom′e-tre)
A procedure utilizing a densitometer.

density (ρ) (den′si-te)
1. The compactness of a substance; the ratio of mass to unit volume, usually expressed as g/cm3 (kg/m3 in the SI system). 2. The quantity of electricity on a given surface or in a given time per unit of volume. 3. In radiological physics, the opacity to light of an exposed radiographic or photographic film; the darker the film, the greater the measured d.. 4. In clinical radiology, a less exposed area on a film, corresponding to a region of greater x-ray attenuation (radiopacity) in the subject; the more light transmitted by the film, the greater the d. of the subject; this is not actually the opposite of the prior definition, since one concerns film d. and the other subject d.. [L. densitas, fr. densus, thick] bone d. quantitative measurement of the mineral content of bone, used as an indicator of the structural strength of the bone and as a screen for osteoporosis buoyant d. the d. that allows a substance to float in some standard fluid. count d. SYN: photon d.. flux d. 1. SYN: flux (4) . 2. either particle flux d., the particle fluence rate, or energy flux d., the energy fluence rate of intensity. Cf.:fluence. incidence d. the person-time incidence rate. optic d. (OD) SYN: absorbance. photon d. the number of counted events recorded in scintigraphy per square centimeter or per square inch of imaged area. SYN: count d.. spin d. the number of nuclear dipoles per unit volume. vapor d. the mass per unit volume of a vapor; since the vapor d. changes with temperature and pressure, it is commonly expressed as a specific gravity, i.e., the weight of the vapor divided by the weight of an equal volume of a reference gas ( e.g., oxygen or hydrogen) at the same temperature and pressure.

dent-, denti-, dento-
Teeth; dental. SEE ALSO: odonto-. [L. dens, tooth]

dental (den′tal)
Relating to the teeth. [L. dens, tooth]

dental engine
The motive power of a dental handpiece that causes it to rotate.

dentalgia (den-tal′je-a)
SYN: toothache. [L. dens, tooth, + G. algos, pain]

dentate (den′tat)
Notched; toothed; cogged. [L. dentatus, toothed]

dentatectomy (den-ta-tek′to-me)
Surgical destruction of the dentate nucleus of the cerebellum. [dentate (nucleus) + G. ectome, excision]

dentatum (den-ta′tum, den-tah′tum)
SYN: dentate nucleus of cerebellum. [L. neut. of dentatus, toothed]

dentes (den′tez)
Plural of dens. [L.]

See dent-.

dentia (den-te′a)
The process of tooth development or eruption. Also serves to denote a relationship to the teeth. [dent- + suffix -ia, condition, process] d. praecox (den-te′a pre-coks) premature tooth eruption. [L. premature] d. tarda (den-tea′ tar′da) delayed tooth eruption. [L. delayed]

denticle (den′ti-kl)
1. SYN: endolith. 2. A toothlike projection from a hard surface. [L. denticulus, a small tooth]

denticulate, denticulated (den-tik′u-lat, -lat-ed)
1. Finely dentated, notched, or serrated. 2. Having small teeth.

dentiform (den′ti-form)
Tooth-shaped; pegged. SEE ALSO: odontoid (1) . [denti- + L. forma, form]

dentifrice (den′ti-fris)
Any preparation used in the cleansing of the teeth, e.g., a tooth powder, toothpaste, or tooth wash. [L. dentifricium, fr. dens, tooth, + frico, pp. frictus, to rub]

dentigerous (den-tij′er-us)
Arising from or associated with teeth, as a d. cyst. [denti- + L. gero, to bear]

dentilabial (den′ti-la′be-al)
Relating to the teeth and lips. [denti- + L. labium, lip]

dentilingual (den-ti-ling′gwal)
Relating to the teeth and tongue. [denti- + L. lingua, tongue]

dentin (den′tin)
SYN: dentine. [L. dens, tooth] hereditary opalescent d. 1. SYN: dentinogenesis imperfecta. 2. SYN: opalescent d.. hypersensitive d. exposed d., usually at the cervical portion of a tooth, painful to touch, sweetness, or temperature changes. interglobular d. imperfectly calcified matrix of d. situated between the calcified globules near the dentinal periphery. irregular d., irritation d. SYN: tertiary d.. opalescent d. d. usually associated with dentinogenesis imperfecta. It gives an unusual opalescent or translucent appearance to the teeth. SYN: hereditary opalescent d. (2) . peritubular d. an electron-dense layer of d. observed adjacent to the odontoblastic process. primary d. d. which forms until the root is completed. reparative d. SYN: tertiary d.. sclerotic d. d. characterized by calcification of the dentinal tubules as a result of injury or normal aging. SYN: transparent d.. secondary d. d. formed by normal pulp function after root end formation is complete. tertiary d. morphologically irregular d. formed in response to an irritant. SYN: irregular d., irritation d., reparative d.. transparent d. SYN: sclerotic d.. vascular d. SYN: vasodentin.

dentinal (den′ti-nal)
Relating to dentin.

dentinalgia (den-ti-nal′je-a)
Dentinal sensitivity or pain. [dentin + G. algos, pain]

dentine (den′ten) [TA]
The ivory forming the mass of the tooth. About 20% is organic matrix, mostly collagen, with some elastin and a small amount of mucopolysaccharide; the inorganic fraction (70%) is mainly hydroxyapatite, with some carbonate, magnesium, and fluoride. The dentinum is traversed by a large number of fine tubules running from the pulp cavity outward; within the tubules are processes from the odontoblasts. SYN: dentinum [TA] , dentin, ebur dentis, substantia eburnea.

dentinocemental (den′ti-no-se-men′tal)
Relating to the dentin and cementum of teeth. SYN: cementodentinal.

dentinoenamel (den′ti-no-e-nam′el)
Relating to the dentin and enamel of teeth. SYN: amelodentinal.


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