|Medical Dictionary - Dictionary of Medicine and Human Biology|
Energy associated with the death or destructive instinct. [coinage on the analogy of libido fr. L. destruo, to destroy]
Enzymes or groups of enzymes catalyzing the removal of a molecule of H2S or substituted H2S from a compound, as in the conversion of cysteine to pyruvic acid by cysteine desulfhydrase (cystathionine γ-lyase). SYN: desulfurases.
Term sometimes applied to the enzyme (aspartate-4-decarboxylase) removing sulfite: 1) from cysteinesulfinate, an intermediate in cysteine degradation, yielding alanine; 2) from sulfinylpyruvate, previously postulated to be formed by deamination of cysteinesulfinate, yielding pyruvate; degradation of sulfinylpyruvate is now considered to be spontaneous, not requiring an enzyme.
A genus of rod-shaped (straight or curved), anaerobic, chemoorganotrophic motile bacteria that stain Gram-negative but have Gram-positive cell walls. Found in soil, the rumen and elsewhere. The type species is D. nigrificans. D. nigrificans a species found in spoiled foods showing “sulfur stinker ” spoilage as a result of hydrogen sulfide production. It is not pathogenic.
Lack of synchrony, as in brain waves. [de- + G. syn, with, + chronos, time]
Abbreviation for diethyltryptamine.
Abbreviation for L. detur, give. [let it be given]
1. A voluntary or involuntary feeling or emotion that accompanies a sense of separation from normal associations or environment. 2. Separation of a structure from its support. exudative retinal d. d. of the retina without retinal breaks, arising from inflammatory disease of choroid, retinal tumors, and retinal angiomatosis. retinal d., d. of retina loss of apposition between the sensory retina and the retinal pigment epithelium. SYN: detached retina, separation of retina. rhegmatogenous retinal d. retinal separation associated with a break, a hole, or a tear in the sensory retina. vitreous d. separation of the peripheral vitreous humor from the retina.
1. The act of discovery. 2. In chromatography, visualization of the separated material.
detector (de-tek′ter, -tor)
The component of a laboratory instrument which detects the chemical or physical signal indicating the presence or quantity of the substance of interest. solid-state d. a d. that uses a crystalline scintillating material rather than an ionization chamber to detect or measure radiation.
1. Cleansing. 2. A cleansing or purging agent, usually salts of long-chain aliphatic bases or acids ( e.g., quaternary ammonium or sulfonic acid compounds) which, through a surface action that depends on their possessing both hydrophilic and hydrophobic properties, exert cleansing (oil-dissolving) and antibacterial effects; acridine derivatives ( e.g., acriflavine, proflavine) as well as other dyes ( e.g., brilliant green, crystal violet) have d. properties for the same reasons. SYN: detersive. [L. de-tergeo, pp. -tersus, to wipe off] anionic detergents detergents, such as soaps (alkali metal salts of long-chain fatty acids), that carry a negative electric charge on a lipidlike molecule and exert a limited antibacterial effect. cationic detergents detergents, such as the amine salts or quaternary ammonium or pyridinium compounds of long-chain fatty acids, that have positively charged groups attached to the larger hydrophobic portions. zwitterionic d. SYN: zwittergents.
The process or condition of becoming worse. [L. deterior, worse] alcoholic d. dementia occurring in persons chronically addicted to alcohol. See chronic alcoholism. senile d. a slowly progressing decline in physical and mental health, apparently due to natural causes attendant upon the processes of aging. See Alzheimer disease.
The factor that contributes to the generation of a trait. [L. determans, determining, limiting] allotypic determinants antigenic determinants of allotypes. antigenic d. the particular chemical group of a molecule that determines immunological specificity. SYN: d. group. disease determinants any variables that directly or indirectly influence the frequency of occurrence and/or the distribution of any given disease; they include specific disease agents, host characteristics, and environmental factors. genetic d. any antigenic d. or identifying characteristic, particularly those of allotypes. SYN: genetic marker. idiotypic antigenic d. SYN: idiotope. isoallotypic determinants genetic determinants that are both isotypic and allotypic in that they appear on heavy chains of all members of at least one subclass of immunoglobulin but also on heavy chains of another subclass of the same species. mathematical d. a formal algebraic operation on the terms of a square matrix of quantities, fundamental in solving multiple simultaneous equations and widely used in regression analysis, notably in epidemiology and quantitative genetics. If d. is zero, the equations have no unambiguous solution.
1. A change, for the better or for the worse, in the course of a disease. 2. A general move toward a given point. 3. The measurement or estimation of any quantity or quality in scientific or laboratory investigation. 4. Discernment of a state or category ( e.g., in diagnosis). 5. A process, both necessary and sufficient, whereby an effect is caused. [L. de-termino, pp. -atus, to limit, determine, fr. terminus, a boundary] cell d. the process by which embryonic cells, previously undifferentiated, take on a specific developmental character. See morphogenesis, induction, evocator. sex d. d. of the sex of a fetus in utero by identification of fetal chromosomes.
The proposition that all behavior is caused exclusively by genetic and environmental influences with no random components, and independent of free will. [L. determino, to limit, fr. terminus, boundary + -ism] psychic d. in psychoanalysis, the concept that all psychological and behavioral phenomena result from antecedent, unconsciously operating causes.
To diminish or remove the poisonous quality of any substance; to lessen the virulence of any pathogenic organism. SYN: detoxify. [L. de, from, + toxicum, poison]
SYN: detoxification. ammonia d. the d. of ammonia and ammonium ion by the formation of ammonium salts, specific nitrogen-excretion products, or l-glutamine.
1. Recovery from the toxic effects of a drug. 2. Removal of the toxic properties from a poison. 3. Metabolic conversion of pharmacologically active principles to pharmacologically less active principles. SYN: detoxication.
A wearing away by use or friction. [L. de-tero, pp. -tritus, to rub off]
Any broken-down material, carious or gangrenous matter, gravel, etc. [L. (see detrition)]
detrusor (de-troo′ser, -sor)
1. A muscle that has the action of expelling a substance. 2. See d. (muscle). [L. detrudo, to drive away]
A procedure in which bladder muscle (detrusor) is reconstructed around the ureterovesical junction to form a competent one-way valve. SEE ALSO: ureteroneocystostomy. SYN: extravesical reimplantation. [detrusor + G. rhaphe, a seam]
Subsidence of a swelling. [L. de, from, + tumesco, to swell up, fr. tumeo, to swell]
The mechanism by which the stroma of the cornea remains relatively dehydrated. [L. de, from, + turgesco, to begin to swell]
Rarely used term for diencephalon. [G. deuteros, second, + enkephalos, brain]
A form of anomalous trichromatism due to a defect of the green-sensitive retinal cones. [G. deuteros, second, + anomalia, anomaly]
A person affected with deuteranopia.
A congenital abnormality of the retina in which there are two rather than three retinal cone pigments (dichromatism) and complete insensitivity to middle wavelengths (green). [G. deuteros, second, + anopia]
Prefix indicating “containing deuterium.”
deuterium (D) (doo-te-r′e-um)
SYN: hydrogen-2. [G. deuteros, second] d. oxide SYN: heavy water.
deutero-, deut-, deuto-
Combining forms meaning two, or second (in a series); secondary. [G. deuteros, second]
Members of the class D. or the phylum Deuteromycota.
A phylum in which the sexual (teleomorph or perfect) part of the life cycle has not been discovered; only the asexual (anamorph or imperfect) part of the life cycle has been found. SEE ALSO: Fungi Imperfecti.
The nucleus of hydrogen-2, composed of one neutron and one proton; it thus has the one positive charge characteristic of a hydrogen nucleus. SYN: deuton, diplon.
Relating to a deuteropathy.
A secondary disease or symptom. [deutero- + G. pathos, suffering]
SYN: deutoplasm. [deutero- + G. plasma, thing formed]
A porphyrin derivative resembling the protoporphyrins except that the two vinyl side chains are replaced by hydrogen.
Dense spherical fibrous granules that occur in the centrosphere and act in the development of centrioles or basal bodies. SYN: procentriole organizer.
A form of parthenogenesis in which the female has offspring of both sexes. SYN: deuterotoky. [deutero- + G. tokos, childbirth]
Of secondary origin following an inductive influence. [deuto- + G. -gen, production]
The posterior nucleated portion of an attached cephalont in a gregarine protozoan, separated by an ectoplasmic septum from the anterior portion, or protomerite. [deuto- + L. meros, part]
The third stage of a mite.
The yolk of a meroblastic egg; the nonliving material in the cytoplasm, especially that stored in the ovum as food for the developing embryo, the commonest types being lipoid droplets and yolk granules. SYN: deuteroplasm. [deuto- + G. plasma, thing formed]
Relating to the deutoplasm.
That which produces or gives rise to deutoplasm. [deutoplasm + G. genos, birth]
The disintegration of deutoplasm. [deutoplasm + G. lysis, dissolution]
Carl E. W., German surgeon, 1872–1942. See D. disease.
Abbreviation for duck embryo origin vaccine.
Occlusion of all or most of the blood vessels to any part or organ. [L. de, away, + vasculum, small vessel, + G. izo, to cause]
To process an exposed photographic or radiographic film in order to turn the latent image into a permanent one. [O.Fr. desveloper, to unwrap, fr. voloper, to wrap]
1. An individual or procedure that develops. 2. SYN: eluent. 3. The chemicals used to develop film by reducing the light-activated silver halide molecules to atomic silver. 4. The factor(s) causing a cell, organ, or organism to undergo a series of orderly changes.
1. The act or process of natural progression in physical and psychological maturation from a previous, lower, or embryonic stage to a later, more complex, or adult stage. 2. The process of chromatography. cognitive d. the evolving d. of the infant's and child's intellectual functions. life-span d. d. and mastery (or loss) of differing biologic, intellectual, behavioral, and social skills in different epochs of the life-span from the prenatal through the gerontological periods of growth. psychosexual d. maturation and d. of the psychic and behavioral phases of sexuality from birth to adult life through the oral, anal, phallic, latency, and genital phases.
Hendrik van, Dutch obstetrician, 1651–1724. See D. pelvis.
SYN: deviation (3) .
1. Denoting or indicative of deviation. 2. An individual exhibiting deviation, especially sexual.
1. A turning away or aside from the normal point or course. 2. An abnormality. 3. In psychiatry and the behavioral sciences, a departure from an accepted norm, role, or rule. SYN: deviance. 4. A statistical measure representing the difference between an individual value in a set of values and the mean value in that set. [L. devio, to turn from the straight path, fr. de, from, + via, way] axis d. deflection of the electrical axis of the heart to the right or left of the normal. SEE ALSO: left axis d., right axis d., axis. SYN: axis shift. conjugate d. of the eyes 1. rotation of the eyes equally and simultaneously in the same direction, as occurs normally; 2. a condition in which both eyes are turned to the same side as a result of either paralysis or muscular spasm. dissociated horizontal d. a tendency often associated with repaired congenital esotropia in which an eye abducts when it is covered, in violation of Herring law. dissociated vertical d. a tendency often associated with congenital esotropia, in which an eye elevates, abducts, and extorts when covered, in violation of Herring law. immune d. SYN: split tolerance. d. to the left SYN: shift to the left (1) . left axis d. a mean electrical axis of the heart pointing to −30° or more negative. See hexaxial reference system. primary d. the ocular d. seen in paralysis of an ocular muscle when the nonparalyzed eye is used for fixation. d. to the right SYN: shift to the right (1) . right axis d. a mean electrical axis of the heart pointing to the right of +90°. See hexaxial reference system. secondary d. ocular d. seen in paralysis of an ocular muscle when the paralyzed eye is used for fixation. sexual d. a sexual practice that is biologically atypical, considered morally wrong, or legally prohibited. See bestiality, pedophilia. SYN: sexual perversion. skew d. a hypertropia in which the eyes move in opposite directions equally; an acquired hypertropia, often fairly comitant, not fitting the characteristic pattern of trochlear nerve damage or of ocular muscle abnormality; often due to a brainstem or cerebellar lesion. standard d. (SD, σ) 1. statistical index of the degree of d. from central tendency, namely, of the variability within a distribution; the square root of the average of the squared deviations from the mean. 2. a measure of dispersion or variation used to describe a characteristic of a frequency distribution.
Eugène, French physician, 1869–1930. See D. disease.
An appliance, usually mechanical, designed to perform a specific function, such as prosthesis or orthesis. [M.E., fr. O.Fr. devis, fr. L. divisum, divided] central-bearing d. in dentistry, a d. which provides a central point of bearing, or support, between upper and lower record bases; it consists of a contacting point which is attached to one base and a plate attached to the other which provides the surface on which the bearing point rests or moves. central-bearing tracing d. in dentistry, a central-bearing d. used for making a tracing and/or for support between upper and lower bases. contraceptive d. a d. used to prevent pregnancy; e.g., occlusive diaphragm, condom, intrauterine d.. intrauterine devices (IUD) pieces of plastic or metal of various shapes ( e.g., coil, loop, bow “T”) inserted into the uterus to exert a contraceptive effect. SYN: intrauterine contraceptive devices. intrauterine contraceptive devices (IUCD) SYN: intrauterine devices. left-ventricular assist d. mechanical pump inserted at some point in the circulation to parallel the activity of the left ventricle and thereby reduce its load. ventricular assist d. any of a variety of mechanical devices that support or replace the pumping function of the left (LVAD) or right ventricle (RVAD). The inflow end of the pump is connected to the ventricle and the outflow end to the aorta (LVAD) or pulmonary artery (RVAD). Most or all of the cardiac output is directed through the d. to allow time for recovery of the patient's damaged heart muscle after myocardial infraction or heart surgery. Also used as “a bridge to transplantation,” i.e., to maintain the patient whose heart will not recover until a donor heart becomes available.
A form of strabismometer.
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