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Medical Dictionary


eczematoid (ek-zem′a-toyd)
Resembling eczema in appearance.

eczematous (ek-zem′a-tus)
Marked by or resembling eczema.

Abbreviation for effective dose; ethyldichloroarsine.

Abbreviation for median effective dose.

edathamil (e-dath′a-mil)
SYN: ethylenediaminetetraacetic acid.

Abbreviation for estimated date of confinement. See Nägele rule.

edea (e-de′a)
The external genitals. [G. aidoia, genitals]

edema (e-de′ma)
An accumulation of an excessive amount of watery fluid in cells or intercellular tissues. [G. oidema, a swelling] ambulant e. e. forming during periods of walking with the legs dependent. angioneurotic e. SYN: angioedema. Berlin e. retinal e. after blunt trauma to the globe. blue e. the swelling and cyanosis of an extremity in hysterical paralysis. brain e. SYN: cerebral e.. brawny e. SYN: nonpitting e.. brown e. e. of the lungs associated with chronic passive congestion. bullous e. a reddened, swollen appearance of the ureteral orifice in the bladder wall, frequently observed with distal ureteral calculi or in tuberculosis of the ureter. bullous e. vesicae a prominent area of focal e. involving the bladder epithelium, consisting of elevated masses of edematous tissue or clusters of clear fluid-filled vesicles; often associated with chronic inflammation or irritation secondary to tubes, foreign bodies, or perivesical inflammation. cachectic e. e. occurring in diseases characterized by wasting and hypoproteinemia; due to low plasma oncotic pressure. SYN: marantic e.. cardiac e. e. resulting from congestive heart failure. cerebral e. brain swelling due to increased volume of the extravascular compartment from the uptake of water in the neuropile and white matter. SEE ALSO: brain swelling. SYN: brain e.. cystoid macular e. e. of the posterior pole of the eye secondary to abnormal permeability of capillaries of the central sensory retina. dependent e. a clinically detectable increase in extracellular fluid volume localized in a dependent area, as of a limb, characterized by swelling or pitting. gestational e. occurrence of a generalized and excessive accumulation of fluid in the tissues of greater than 1+ pitting after 12 hours' bed rest, or of a weight gain of 5 pounds or more in 1 week due to the influence of pregnancy. e. glottidis e. of the larynx. heat e. e. caused by excessively high external temperature. hereditary angioneurotic e. (HANE) [MIM*106100] a relatively rare form of e. characterized by onset, usually in adolescence, of erythema followed by e., involving the upper respiratory or gastrointestinal tracts, associated with either a deficiency of C1 esterase inhibitor or a functionally inactive form of the inhibitor. There are two clinically indistinguishable forms: type I, in which the serum level of C1 esterase inhibitor is low (up to 30% of normal) and type II, in which the level is normal or elevated. There is uncontrolled activation of early complement components and production of a kininlike factor that induces the angioedema; death may occur from upper respiratory tract e. and asphyxia. Inheritance is autosomal dominant, caused by mutation in the C1-esterase inhibitor gene (C1NH) on chromosome 11q. hydremic e. obsolete term for e. occurring in states marked by pronounced hydremia. infantile acute hemorrhagic e. of the skin a generally benign form of cutaneous vasculitis, characterized by ecchymotic purpura, often in a cockade pattern, and inflammatory e. in infants. inflammatory e. a swelling due to effusion of fluid in the soft parts surrounding a focus of inflammation. lymphatic e. e. due to stasis in the lymph channels. marantic e. SYN: cachectic e.. menstrual e. retention of water and increase in weight, which occurs during or preceding menstruation. e. neonatorum a diffuse, firm, and commonly fatal e. occurring in the newborn, usually beginning in the legs and spreading upward. nephrotic e. e. resulting from renal dysfunction. noninflammatory e. e. due to mechanical or other causes, not marked by inflammation or congestion. nonpitting e. swelling of subcutaneous tissues which cannot be indented easily by compression. Usually due to metabolic abnormality, such as increased glycosaminoglycan content, like that which occurs in Graves disease (pretibial myxedema) or in early phase of scleroderma. SYN: brawny e.. nutritional e. a form of swelling caused by insufficient protein intake resulting in hypoproteinemia and low plasma oncotic pressure. periodic e. SYN: angioedema. pitting e. e. that retains for a time the indentation produced by pressure. premenstrual e. menstrual e.. pulmonary e. e. of lungs usually resulting from mitral stenosis or left ventricular failure. salt e. e. from excessive intake or retention of sodium chloride. solid e. infiltration of the subcutaneous tissues by mucoid material, as in myxedema. Yangtze e. SYN: gnathostomiasis.

edematization (e-dem′a-ti-za′shun)
Making edematous.

edematous (e-dem′a-tus)
Marked by edema.

edentate (e-den′tat)
SYN: edentulous. [L. edentatus]

edentulous (e-den′tu-lus)
Toothless, having lost the natural teeth. SYN: edentate. [L. edentulus, toothless]

edestin (e-des′tin)
A hexameric globulin derived from the castor oil bean, hemp seed, and other seeds. It will support the growth of animals in the absence of other dietary proteins.

edetate (ed′e-tat)
USAN-approved contraction for ethylenediaminetetraacetate, the anion of ethylenediaminetetraacetic acid; various edetates are used as chelating agents to carry cations in ( e.g., ferric sodium e. as an iron ion carrier) or out ( e.g., sodium e. for calcium or heavy metal ion removal).

edetate calcium disodium
Contracted name for a salt of ethylenediaminetetraacetate, an agent used as a chelator of lead and some other heavy metals. Available in several forms: disodium, sodium, and trisodium.

edetic acid (e-det′ik)
SYN: ethylenediaminetetraacetic acid.

edge (ej)
A line at which a surface terminates. SEE ALSO: border, margin. cutting e. 1. the beveled, knifelike, sharpened working angle of a dental hand instrument; 2. SYN: incisal margin. denture e. SYN: denture border. incisal e. SYN: incisal margin. leading e. the initial part of a waveform. shearing e. SYN: incisal margin.

Ludwig, German anatomist, 1855–1918. See E.-Westphal nucleus.

edisylate (e-dis′i-lat)
USAN-approved contraction for 1,2-ethanedisulfonate, -O3S(CH2)2SO3-.

Gustav J.F., German physician, 1842–1910. See E. reagent.

Abbreviation for multiple epiphyseal dysplasia.

Pehr, Australian scientist, 1916–1977. See E. method, E. reagent.

Acronym for endothelium-derived relaxing factor, now known to be nitric oxide.

Frederick W., English ophthalmologist, 1863–1953. See Edridge-Green lamp.

edrophonium chloride (ed-ro-fo′ne-um)
A short-duration competitive antagonist of skeletal muscle relaxants (curare derivatives and gallamine triethiodide) and an anticholinesterase, used as an antidote for curariform drugs, as a diagnostic agent in myasthenia gravis, and in myasthenic crisis.

Abbreviation for Ehlers-Danlos syndrome.

Abbreviation for expanded disability status scale.

Abbreviation for ethylenediaminetetraacetic acid.

educt (e′dukt)
An extract.

edulcorant (e-dul′ko-rant)

edulcorate (e-dul′ko-rat)
To sweeten or render less acrid. [L. e- intensive, + dulcoro, to sweeten, fr. dulcor, sweetness, fr. dulcis, sweet]

James Hilton, English physician and medical geneticist, *1928. See E. syndrome.

M.L., U.S. physician, *1906. See Carpentier-E. valve, Starr-E. valve.

Edwardsiella (ed′ward-se-el′la)
A genus of Gram-negative, facultatively anaerobic bacteria (family Enterobacteriaceae) containing motile, peritrichous, nonencapsulated rods. The type species is E. tarda, which is occasionally isolated from the stools of both healthy humans and those with diarrhea, from the blood of humans and other animals, and from human urine. E. tarda is an etiologic agent of gastroenteritis in humans. The two other species in this genus are E. hoshinae and E. ictaluri.

Abbreviation for eastern equine encephalomyelitis.

Abbreviation for electroencephalogram; electroencephalography.

eel (el)
Any of a number of scaleless, snakelike fish. [M.E. ele, fr. O.E. ael] vinegar e. SYN: Turbatrix aceti.

Abbreviation for eye, ear, nose, and throat. See also ENT.

effacement (e-fas′ment)
The thinning out of the cervix just before or during labor.

effect (e-fekt′)
The result or consequence of an action. [L. efficio, pp. effectus, to accomplish, fr. facio, to do] abscopal e. a reaction produced following irradiation but occurring outside the zone of actual radiation absorption. additive e. an e. wherein two or more substances or actions used in combination produce a total e., the same as the arithmetic sum of the individual effects. after-e. aftereffect. Anrep e. a small transient positive inotropic e. of abrupt increases of systolic aortic and left ventricular pressures related to recovery from transient subendocardial ischemia ( e.g., cold pressor test). Arias-Stella e. SYN: Arias-Stella phenomenon. autokinetic e. in psychology, the apparent drifting about of a small, fixed, spot of light which is being observed in a dark room. Bernoulli e. the decrease in fluid pressure that occurs in converting potential to kinetic energy when motion of the fluid is accelerated, in accordance with Bernoulli law; applied in water aspirators, atomizers, and humidifiers in which a gas is accelerated across the end of a narrow, fluid-filled orifice. Bohr e. the influence exerted by carbon dioxide on the oxygen dissociation curve of blood, i.e., the curve is shifted to the right, which means an apparent reduction in the affinity of hemoglobin for oxygen. Cf.:Haldane e.. Bowditch e. homeometric autoregulation of cardiac function induced by changing heart rate. Circe e. an e. observed in enzyme catalysis in which accelerated diffusion of the substrate occurs through attractive forces of the enzyme's active site. clasp-knife e. SYN: clasp-knife spasticity. Compton e. in the absorption of electromagnetic radiation of medium energy, a decrease in energy of the bombarding photon with the dislodgement of an orbital electron, usually from an outer shell. SYN: Compton scattering. Cotton e. the positive and negative displacement from zero of the rotation of plane polarized monochromatic light and the change of monochromatic circularly polarized light into elliptically polarized light in the immediate vicinity of the absorption band of the substance through which the light passes. SEE ALSO: optic rotatory dispersion, circular dichroism. Crabtree e. inhibition of cellular respiration of isolated systems by high concentrations of glucose; a “reciprocal” of Pasteur e.; due, in part, to the inhibition of hexokinase by elevated glucose 6-phosphate. Cf.:Pasteur e.. cumulative e. the condition in which repeated administration of a drug may produce effects that are more pronounced than those produced by the first dose. SYN: cumulative action. Cushing e. SYN: Cushing phenomenon. cytopathic e. degenerative changes in cells (especially in tissue culture) associated with the multiplication of certain viruses; when, in tissue culture, spread of virus is restricted by an overlay of agar (or other suitable substance) the cytopathic e. may lead to formation of plaque. Doppler e. a change in frequency observed when the sound source and observer are in relative motion away from or toward each other. SEE ALSO: Doppler shift. SYN: Doppler phenomenon. electrophonic e. the sensation of hearing produced when an alternating current of suitable frequency and magnitude is passed from an external source through the head of a person. experimenter effects the influence of the experimenter's behavior, personality traits, or expectancies on the results of that person's own research. See double blind study. Fahraeus-Lindqvist e. the decrease in apparent viscosity that occurs when a suspension, such as blood, is made to flow through a tube of smaller diameter; observed in tubes less than about 0.3 mm in diameter. SYN: sigma e.. Fenn e. the increased liberation of heat in a stimulated muscle when it is allowed to do mechanical work; the amount of heat liberated is increased in proportion to the distance the muscle is allowed to shorten and in proportion to the tension it must develop ( e.g., the weight it lifts) during shortening; thus increased chemical energy is consumed both to liberate increased heat and to do increased mechanical work. first-pass e. SYN: first-pass metabolism. flash-lag e. the apparent lagging behind a moving object of a portion of it that flashes briefly. founder e. an unusually high frequency of a gene in a particular population derived from a small set of unrepresentative ancestors. gene dosage e. in codominant alleles, the more or less linear relationship between the phenotypic value and the number of genes of one type substituted by another type. generation e. variation in health status arising from the different causal factors of disease to which each successive generation born is exposed as it passes through life. Haldane e. the promotion of carbon dioxide dissociation in blood by an increase in the oxygenation of hemoglobin. halo e. 1. the e. (usually beneficial) that the manner, attention, and caring of a provider have on a patient during a medical encounter, regardless of what medical procedure or services the encounter involves; 2. the influence upon an observation of the observer's perception of the characteristics of the individual observed (other than the characteristics under study) or the influence of the observer's recollection or knowledge of findings on a previous occasion. Hawthorne e. the e. (usually positive or beneficial) of being under study, upon the persons being studied; their knowledge of the study often influences their behavior. [city in Illinois; site of the Western Electric plant] healthy worker e. phenomenon observed initially in studies of occupational diseases; workers usually exhibit lower overall death rates than the general population because severely ill and disabled people are excluded from employment. hyperchromic e. an increase in absorptivity (or extinction) at a particular wavelength of light by a solution or substance due to structural changes in a molecule. hypochromic e. a phenomenon in which an individual molecule, containing several chromophores, has a certain absorptivity (or optical density) at a given wavelength that is less than the sum of the optical densities of the individual chromophores (at that same wavelength). Mach e. the appearance of a light or dark line on a radiograph where there is a concave or convex interface in the subject, a physiologic optical form of edge enhancement. SEE ALSO: Mach band. e. modifier a factor that modifies the e. of a putative causal factor under study; e.g., age is an e. modifier for many conditions. nuclear Overhauser e. (NOE) an enzyme seen in nuclear magnetic resonance in which there is a through-space nearest-neighbor interaction. Orbeli e. the fatigue of a muscle stimulated by its nerve ( i.e., indirectly) is reduced by concurrent stimulation of sympathetic fibers to the muscle; thought to be caused by norepinephrine diffusing from adrenergic fibers which innervate blood vessels in the muscle. oxygen e. enhancement of radiosensitivity of cells by a high concentration of oxygen, and, conversely, decreased radiosensitivity in a hypoxic environment. Pasteur e. the inhibition of fermentation by oxygen, first observed by Pasteur; either not observed, or only slightly observed, in malignant tumors. Cf.:Crabtree e.. photechic e. the ability of an agent, other than light, to make a developable latent image in a photographic film emulsion. SYN: Russell e.. photoelectric e. 1. the loss of electrons from the surface of a metal upon exposure to light; 2. a mode of interaction of radiation with matter in which all of the energy of the incident photon is absorbed, with ejection of a photoelectron and characteristic radiation from filling the vacancy from another shell; since the energy absorption per gram of tissue is proportional to the cube of the atomic number, this mode is important in diagnostic radiography. piezoelectric e. the property of certain crystalline or ceramic materials to emit electricity when deformed and to deform when an electric current is passed across them, a mechanism of interconverting electrical and acoustic energy; an ultrasound transducer sends and receives acoustic energy using this e.. position e. a change in the phenotypic expression of one or more genes due to a change in its physical location with respect to other genes; may result from change in chromosome structure or from crossing-over. Purkinje e. SYN: Purkinje phenomenon. quantal e. an e. that can be expressed only in binary terms, as occurring or not occurring. Raman e. a change in frequency undergone by monochromatic light scattered in passage through a transparent substance whose characteristics determine the amount of change, yielding a spectrum in which the incident wavelength band is flanked by small satellite bands of greater and lesser wavelengths. Rivero-Carvallo e. inspiratory increase in the systolic murmur of tricuspid insufficiency; the characteristic distinguishing tricuspid insufficiency from mitral insufficiency. Russell e. SYN: photechic e.. second gas e. when a constant concentration of an anesthetic like halothane is inspired, the increase in alveolar concentration is accelerated by concomitant administration of nitrous oxide, because alveolar uptake of the latter creates a potential subatmospheric intrapulmonary pressure that leads to increased tracheal inflow. sigma e. SYN: Fahraeus-Lindqvist e.. Somogyi e. in diabetes, a rebound phenomenon of reactive hyperglycemia in response to a preceding period of relative hypoglycemia that has increased secretion of hyperglycemic agents (epinephrine, norepinephrine, glucagon, cortisol, and growth hormone); described in diabetic patients given too much insulin who developed unrecognized nocturnal hypoglycemia that made them hyperglycemic (suggesting insufficient insulin) when tested the next morning. Staub-Traugott e. in normal persons, a drop in blood glucose which follows a second oral dose of glucose given 30 minutes or so after the first. Stiles-Crawford e. light that enters through the center of the pupil produces a greater visual e. than light that enters obliquely. synergistic e. SYN: synergism. Tyndall e. SYN: Tyndall phenomenon. Venturi e. term applied to the operation of a Venturi tube and similar systems. Wedensky e. a relatively long enhancing e. following application of a maximal shock or stimulus to a neuromuscular preparation during which a subthreshold stimulation, otherwise too small to evoke a response, will produce a response; a relatively prolonged lowered threshold of excitability following a maximal shock. Wolff-Chaikoff e. SYN: Wolff-Chaikoff block. Zeeman e. the splitting of spectral lines into three or more symmetrically placed lines when the light source is subjected to a magnetic field.

1. A measure of the accuracy or success of a diagnostic or therapeutic technique when carried out in an average clinical environment. Cf.:efficacy. 2. The extent to which a treatment achieves its intended purpose. relative biologic e. (RBE) a factor used to compare the biologic effect of absorbed doses of different types and energies of ionizing radiation. It is determined by the ratio of an absorbed dose of the particular radiation in question to the absorbed dose of a reference radiation required to produce an identical biologic effect in a specific organism, organ, or tissue.

effector (e-fek′tor, -tor)
1. C. Sherrington term for a peripheral tissue that receives nerve impulses and reacts by contraction (muscle), secretion (gland), or a discharge of electricity (electric organ of certain bony fishes). 2. A small metabolic molecule that by combining with a repressor gene depresses the activity of an operon. 3. A small molecule that binds to a protein and, in so doing, alters the activity of that protein. 4. A substance, technique, procedure, or individual that causes an effect. [L. producer]

effemination (e-fem-i-na′shun)
Acquisition of feminine characteristics, either physiologically as part of female maturation, or pathologically by individuals of either sex. [L. ef-femino, pp. -atus, to make feminine, fr. ex, out, + femina, woman]

efferent (ef′er-ent)
Conducting (fluid or a nerve impulse) outward from a given organ or part thereof; e.g., the e. connections of a group of nerve cells, e. blood vessels, or the excretory duct of an organ. [L. efferens, fr. effero, to bring out] gamma e. the thin axon of a gamma motor neuron innervating the intrafusal muscle fibers of a muscle spindle.

effervesce (ef-er-ves′)
To boil up or form bubbles rising to the surface of a fluid in large numbers, as in the evolution of CO2 from aqueous solution when the pressure is reduced. [L. ef-fervesco, to boil up, from ferveo, to boil]

effervescent (ef-er-ves′ent)
1. Boiling; bubbling; effervescing. 2. Causing to effervesce, as an e. powder. 3. Tending to effervesce when freed from pressure, as an e. solution.

efficacy (ef′i-ka-se)
The extent to which a specific intervention, procedure, regimen, or service produces a beneficial result under ideal conditions. Cf.:effectiveness. [L. efficacia, fr, ef-ficio, to perform, accomplish]

efficiency (e-fish′en-se)
1. The production of the desired effects or results with minimum waste of time, money, effort, or skill. 2. A measure of effectiveness; specifically, the useful work output divided by the energy input. quantum e. SYN: quantum yield. visual e. a rating used in computing compensation for industrial ocular injuries, incorporating measurements of central acuity, visual field, and ocular motility.

effleurage (e-fler-ahz′)
A stroking movement in massage. [Fr. effleurer, to touch lightly]

effloresce (e-flor-es′)
To become powdery by losing the water of crystallization on exposure to a dry atmosphere. [L. ef-floresco (exf-), to blossom, fr. flos (flor-), flower]

efflorescent (e-flor-es′ent)
Denoting a crystalline body that gradually changes to a powder by losing its water of crystallization on exposure to a dry atmosphere.

effluvium, pl .effluvia (e-floo′ve-um, -e-a)
Shedding of hair. SEE ALSO: defluxion (1) . [L. a flowing out, fr. ef-fluo, to flow out] anagen e. sudden diffuse hair shedding with cancer chemotherapy or radiation, usually reversible when treatment ends. telogen e. increased transient shedding of normal club hairs by premature development of telogen in anagen follicles, resulting from various kinds of stress, e.g., childbirth, shock, drug intake or cessation of an oral contraceptive, fever, and dieting with marked weight loss.

effort (ef′ert)
Deliberate exertion of physical or mental power. distributed e. in psychology, learning that involves small units of work and interpolated rest periods, as contrasted with massed learning, in which the individual works continually until the skill is mastered.

effuse (ef-uz′)
Thin and widely spread; denoting the surface character of a bacterial culture. [L. ef-fundo, pp. -fusus; to pour out]

effusion (e-fu′zhun)
1. The escape of fluid from the blood vessels or lymphatics into the tissues or a cavity. 2. A collection of the fluid effused. [L. effusio, a pouring out] complex pleural e. a pleural e. without actual infection but with signs of a high degree of inflammation ( e.g., low pH, low glucose, high lactate dehydrogenase, many white cells). joint e. increased fluid in synovial cavity of a joint. loculated pleural e. pleural e. that is confined to one or more fixed pockets in the pleural space. middle-ear e. a condition in which the air in the middle ear has been replaced with serous or mucoid fluid as a consequence of otitis media. SYN: secretory otitis media, serous otitis media. parapneumonic e. pleural e. associated with pneumonia pericardial e. increased fluid within the pericardial sac; can cause circulatory compromise by compression of the heart; most often caused by inflammation, infection, malignancy, and uremia. SYN: dropsy of pericardium. pleural e. increased fluid in the pleural space; can cause shortness of breath by compression of the lung and/or increased intrathoracic pressure resulting in mediastinal shift and increased work of breathing; a transudative e. has low protein content and is usually due to heart failure, uremia, or hypoalbuminemia; an exudative e. has high protein and cell count and is due most often to inflammation, malignancy, or infection; an infected pleural e. is an empyema; a pleural e. associated with pneumonia is a parapneumonic e.; a pleural e. without actual infection but with signs of a high degree of inflammation ( e.g., low pH, low glucose, high lactate dehydrogenase, many white cells) is a complex pleural e. and is frequently associated with pneumonia; a loculated pleural e. is not free-flowing in the pleural space but rather confined to one or more fixed pockets. SYN: hydrothorax. subpulmonic e. a collection of fluid in the pleural space mostly located radiographically between the diaphragm and the basal surface of the lung.

eflornithine hydrochloride (e-flor′ni-then)
An antineoplastic and antiprotozoal orphan drug used in the treatment of Pneumocystis carinii pneumonia in AIDS and of Trypanosoma brucei gambiense sleeping sickness.

Abbreviation for esophagogastroduodenoscopy.

egesta (e-jes′ta)
Unabsorbed food residues that are discharged from the digestive tract. [L. e-gero, pp. -gestus, to carry out, discharge]

Abbreviation for epidermal growth factor.

Abbreviation for epidermal growth factor receptor .

egg (eg)
The female sexual cell, or gamete; after fertilization and fusion of the pronuclei it is a zygote and no longer an e.. In reptiles and birds, the e. is provided with a protective shell, membranes, albumin, and yolk for the nourishment of the embryo. SEE ALSO: oocyte, ovum. [A.S. aeg] centrolecithal e. an e. in which the yolk is concentrated near the center of the e. cell, as is the case in many of the insects. homolecithal e. an e. in which the total amount of yolk is small and fairly uniformly distributed throughout the cytoplasm. SYN: isolecithal e.. isolecithal e. SYN: homolecithal e.. microlecithal e. an e. containing a small amount of deutoplasm. telolecithal e. an e. containing a relatively large quantity of deutoplasm concentrated at the abapical pole; e.g., eggs of reptiles and birds.

egg cluster
One of the clumps of cells resulting from the breaking up of the gonadal cords in the ovarian cortex; these clumps later develop into primary ovarian follicles.

Fritz, Swiss internist, 1863–1938. See E. line.

Cary, U.S. physician, 1884–1966. See E. method, Bradbury-E. syndrome.

The calcareous envelope of a bird's egg.


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