Medical Dictionary

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entoptic (en-top′tik)
Within the eyeball. Often used to describe visual phenomena generated by mechanical or electrical stimulations of the retina. [ento- + G. optikos, relating to vision]

entoretina (en-to-ret′i-na)
The layers of the retina from the outer plexiform to the nerve fiber layer inclusive. SYN: Henle nervous layer.

entosarc (en′to-sark)
SYN: endosarc.

Entozoa (en-to-zo′a)
A nontaxonomic name for the branch of the kingdom Animalia, whose members possess a digestive cavity or tract; includes all vertebrates and higher invertebrate forms. [ento- + G. zoon, animal]

entozoal (en-to-zo′al)
Relating to entozoa.

entozoon, pl .entozoa (en-to-zo′on, -a)
An animal parasite whose habitat is any of the internal organs or tissues. [ento- + G. zoon, animal]

entrails (en′tralz)
The viscera of an animal.

entropion, entropium (en-tro′pe-on, -pe-um)
1. Inversion or turning inward of a part. 2. The infolding of the margin of an eyelid. [G. en, in, + trope, a turning] atonic e. e. that follows loss of tone of the orbicularis oculi muscle or elasticity of the skin. cicatricial e. e. that follows scarring of the palpebral conjunctiva. spastic e. e. that arises from excessive contracture of the orbicularis oculi muscle.

entropionize (en-tro′pe-on-iz)
To invert a part.

entropy (S) (en′tro-pe)
That fraction of heat (energy) content not available for the performance of work, usually because (in a chemical reaction) it has been used to increase the random motion of the atoms or molecules in the system; thus, e. is a measure of randomness or disorder. E. occurs in the Gibbs free energy (G) equation: ΔG = ΔH − TΔS (ΔH, change in enthalpy or heat content; T, absolute temperature; ΔS, change in e.). SEE ALSO: second law of thermodynamics. [G. entropia, a turning toward]

entypy (en′ti-pe)
A type of gastrulation seen in some early mammalian embryos in which the endoderm covers the embryonic and amniotic ectoderm; part of the preplacental trophoblast may also be covered. [G. entype, pattern]

enucleate (e-noo′kle-at)
To remove entirely; to shell like a nut, as in the removal of an eye from its capsule or a tumor from its compressed surrounding tissue.

enucleation (e-noo-kle-a′shun)
1. Removal of an entire structure (such as an eyeball or tumor), without rupture, as one shells the kernel of a nut. 2. Removal or destruction of the nucleus of a cell. [L. enucleo, to remove the kernel, fr. e, out, + nucleus, nut, kernel]

enuresis (en-u-re′sis)
Involuntary discharge or leakage of urine. [G. en-oureo, to urinate in] diurnal e. urinary accidents during wakefulness. nocturnal e. urinary incontinence during sleep. SYN: bed-wetting.

envelope (en′ve-lop)
In anatomy, a structure that encloses or covers. corneocyte e. an electron-dense, 10–15 nm thick layer of highly cross-linked protein on the cytoplasmic surface of the cell membrane of epidermal corneocytes; it is highly resistant to proteolytic agents. SYN: subplasmalemmal dense zone. nuclear e. the double membrane at the boundary of the nucleoplasm; it has regularly spaced pores covered by a disklike nuclear pore complex and a space or cisterna about 150 Å wide between the two layers; the outer membrane is continuous at intervals with the endoplasmic reticulum. SYN: caryotheca, karyotheca, nuclear membrane. viral e. the outer structure or coat that encloses the nucleocapsids of some viruses that mature by budding through the membrane cell; may contain lipoprotein.

envenomation (en-ven-o-ma′shun)
The act of injecting a poisonous material (venom) by sting, spine, bite, or other venom apparatus.

environment (en-vi′ron-ment)
The milieu; the aggregate of all of the external conditions and influences affecting the life and development of an organism. It can be divided into physical, biological, social, cultural, etc., any or all of which can influence the health status of the population. [Fr. environ, around]

envy (en′ve)
One's feeling of discontent or jealousy resulting from comparison with another person. penis e. the psychoanalytic concept in which a female envies male characteristics or capabilities, especially the possession of a penis.

enzootic (en-zo-ot′ik)
SYN: endemic. [G. en, in, + zoon, animal]

enzygotic (en-zi-got′ik)
Derived from a single fertilized ovum; denoting twins so derived. [G. eis (en), one, + zygote]

enzymatic (en-zi-mat′ik)
Relating to an enzyme. SYN: enzymic.

enzyme (en′zim)
A protein that acts as a catalyst to induce chemical changes in other substances, itself remaining apparently unchanged by the process. Enzymes, with the exception of those discovered long ago ( e.g., pepsin, emulsin), are generally named by adding -ase to the name of the substrate on which the e. acts ( e.g., glucosidase), the substance activated ( e.g., hydrogenase), and/or the type of reaction ( e.g., oxidoreductase, transferase, hydrolase, lyase, isomerase, ligase or synthetase—these being the six main groups in the E. Nomenclature Recommendations of the International Union of Biochemistry). For individual enzymes not listed below, see the specific name. SYN: organic catalyst (1) . [G. + L. en, in + zyme, leaven] acetyl-activating e. SYN: acetyl-CoA ligase. acyl-activating e. 1. SYN: long-chain fatty acid-CoA ligase. 2. SYN: butyrate-CoA ligase. adaptive e. SYN: induced e.. allosteric e. an e. that exhibits the property of allosterism. amino acid activating e. SYN: aminoacyl-tRNA synthetases. angiotensin-converting e. (ACE) SYN: peptidyl dipeptidase A. antitumor e. an e. that stimulates the degradation of a particular metabolite that cannot be synthesized by tumor cells, inhibits the synthesis of a metabolite needed by tumor cells, or inhibits tumor-specific DNA utilization; E.G., asparaginase. autolytic e. an e. capable of causing lysis of the cell forming it. branching e. SYN: 1,4-α-d-glucan-branching e.. β-carotene-cleavage e. SYN: β-carotene 15,15′-dioxygenase. citrate-cleavage e. SYN: ATP citrate (pro-3S)-lyase. cold-sensitive e. an e. that loses its stability as the temperature is lowered. condensing e. SYN: citrate synthase. constitutive e. an e. that is constantly produced by the cell, regardless of the growth conditions. Cf.:induced e.. cooperative e. an e. that exhibits the property of cooperativity. D e. SYN: 4-α-d-glucanotransferase. deamidizing enzymes SYN: amidohydrolases. deaminating enzymes SYN: deaminases. debranching enzymes enzymes that bring about destruction of branches in glycogen; formerly considered to be one e., now known to be a mixture of transferases (4-α-d-glucanotransferase) and hydrolases (amylo-1,6-glucosidase). SYN: debranching factors. digestive enzymes 1. enzymes that are utilized in the digestive system; 2. enzymes that are hydrolases of macromolecules ( E.G., amylases, proteinases). disproportionating e. SYN: 4-α-d-glucanotransferase. extracellular e. an e. performing its functions outside a cell; e.g., the various digestive enzymes. SYN: exoenzyme. heat-stable e. SYN: thermostable e.. hydrolyzing enzymes SYN: hydrolases. immobilized e. an e. that has been bound, usually covalently, to an insoluble organic or inorganic matrix or has been encapsulated. induced e., inducible e. 1. an e. that can be detected in a growing culture of a microorganism, after the addition of a particular substance (inducer) to the culture medium, but was not detectable prior to the addition and can act on the inducer. A prototype is the β-galactosidase of Escherichia coli, synthesized upon the addition of various galactosides, whether or not these are good substrates. Cf.:constitutive e.. 2. any e. that has its rate of biosynthesis increased due to the presence of the substrate or some other molecular entity. SYN: adaptive e.. intracellular e. an e. that performs its functions within the cell that produces it; most enzymes are intracellular enzymes. SYN: endoenzyme (1) . Kornberg e. dNA polymerase I from Escherichia coli. malate-condensing e. SYN: malate synthase. malic e. SYN: malate dehydrogenase. marker e. an e. that is used to identify a specific cell type, cell organelle, or cell component. membrane e. an e. present or embedded in a biomembrane. methionine-activating e. SYN: methionine adenosyltransferase. new yellow e. a former name for the d-amino-acid oxidase found in yeast, a flavoenzyme; so-called to distinguish it from Warburg old yellow e.. Cf.:amino acid oxidases. old yellow e. SYN: NADPH dehydrogenase. P e. SYN: phosphorylase. pantoate-activating e. SYN: pantothenate synthetase. phosphorylase-rupturing e. (PR e.) SYN: phosphorylase phosphatase. photoreactivating e. (PR e.) SYN: deoxyribodipyrimidine photolyase. PR e. abbreviation for phosphorylase-rupturing e.; photoreactivating e.. Q e. 1,4-α-glucan branching e. in plants. R e. SYN: α-dextrin endo-1,6-α-glucosidase. reducing e. SYN: reductase. repair e. an e. that can catalyze the repair of damaged DNA; E.G., DNA ligase. repressible e. an e. that is produced continuously unless production is repressed by excess of an inhibitor (corepressor). SEE ALSO: inactive repressor. respiratory e. a tissue e. that is part of an oxidation-reduction system accomplishing the conversion of substrates to CO2 and H2O and the transfer of the electrons removed to O2. restriction e. SYN: restriction endonuclease. RNA e. SYN: ribozyme. Schardinger e. SYN: xanthine oxidase. splitting enzymes enzymes that, like aldolases, catalyze the conversion of a molecule into two smaller molecules without the addition or subtraction of any atoms. T e. 1,4-α-d-glucan 6-α-d-glucosyltransferase. terminal addition e. SYN: DNA nucleotidylexotransferase. thermostable e. an e. that is not readily subject to destruction or alteration by heat. SYN: heat-stable e.. thiol e. an e. whose activity depends on a free thiol group. transferring enzymes SYN: transferases. Warburg old yellow e. SYN: NADPH dehydrogenase. SEE ALSO: new yellow e., yellow e.. Warburg respiratory e. SYN: Atmungsferment. yellow e. SYN: flavoenzyme. SEE ALSO: Warburg old yellow e., new yellow e..

Enzyme Commission
See EC.

enzymic (en-zi′mik)
SYN: enzymatic.

enzymologist (en-zi-mol′o-jist)
A specialist in enzymology.

enzymology (en-zi-mol′o-je)
The branch of chemistry concerned with the properties and actions of enzymes. [enzyme + G. logos, study]

enzymolysis (en-zi-mol′i-sis)
1. The splitting or cleavage of a substance into smaller parts by means of enzymatic action. 2. Lysis by the action of an enzyme. [enzyme + G. lysis, dissolution]

enzymopathy (en-zi-mop′a-the)
Any disturbance of enzyme function, including genetic deficiency or defect in specific enzymes. [enzyme + G. pathos, disease]

EOG
Abbreviation for electrooculography; electroolfactogram.

eosin (e′o-sin)
A derivative of fluorescein used as a fluorescent acid dye for cytoplasmic stains and counterstains in histology and in Romanovsky-type blood stains. [G. eos, dawn] e. B the disodium salt of 4′,5′-dibromo-2′,7′-dinitrofluorescein. SYN: acid red 91, e. I bluish. [C.I. 45400] e. I bluish SYN: e. B. e. y, e. Y the disodium salt of 2′,4′,5′,7′-tetrabromofluorescein. SYN: acid red 87, e. yellowish. [C.I. 45380] e. yellowish SYN: e. y.

eosinocyte (e-o-sin′o-sit)
SYN: eosinophilic leukocyte.

eosinopenia (e′o-sin-o-pe′ne-a)
The presence of eosinophils in an abnormally small number in the peripheral bloodstream. SYN: hypoeosinophilia. [eosino(phil) + G. penia, poverty]

eosinophil, eosinophile (e-o-sin′o-fil, -fil)
SYN: eosinophilic leukocyte. [eosin + G. philos, fond]

eosinophilia (e′o-sin-o-fil′e-a)
SYN: eosinophilic leukocytosis. simple pulmonary e. pulmonary infiltrates seen as transient migratory shadows on the chest x-ray, accompanied by blood e.; often symptomless, but there may be cough, fever, and breathlessness; most cases are due to worm infestation, especially by Ascaris lumbricoides; a few cases follow administration of drugs. SYN: Löffler syndrome (1) . tropical e. e. associated with cough and asthma, caused by occult filarial infection without evidence of microfilaremia, occurring most frequently in India and Southeast Asia.

eosinophilic (e-o-sin-o-fil′ik)
Staining readily with eosin dyes; denoting such cell or tissue elements.

eosinophiluria (e-o-sin′o-fil-u′re-a)
Presence of eosinophils in the urine.

eosinotactic (e′o-sin-o-tak′tik)
Exerting a force of attraction or repulsion on eosinophile cells. [eosino(phile) + G. taktikos, in orderly arrangement]

eosinotaxis (e′o-sin-o-tak′sis)
Movement of eosinophils with reference to a stimulus which attracts or repels them.

eosophobia (e-o-so-fo′be-a)
Morbid dread of the dawn. [G. eos, dawn, + phobos, fear]

EP
Abbreviation for endogenous pyrogen.

epactal (e-pak′tal)
SYN: supernumerary. [G. epaktos, imported, fr. epago, to bring on or in]

epamniotic (ep′am-ne-ot′ik)
Upon or above the amnion. [G. epi, upon, + amnion]

eparterial (ep′ar-ter-e-al)
Upon or superior to an artery. [G. epi, upon, + arteia, artery]

epaxial (ep-ak′se-al)
Above or behind any axis, such as the spinal axis or the axis of a limb. [G. epi, upon, + L. axis, axis]

EPEC
Abbreviation for enteropathogenic Escherichia coli.

ependyma (ep-en′di-ma) [TA]
The cellular membrane lining the central canal of the spinal cord and the brain ventricles. SYN: endyma. [G. e., an upper garment]

ependymal (ep-en′di-mal)
Relating to the ependyma.

ependymitis (ep-en-di-mi′tis)
Inflammation of the ependyma.

ependymoblast (ep-en′di-mo-blast)
An embryonic ependymal cell. [ependyma + G. blastos, germ]

ependymoblastoma (ep-en′di-mo-blas-to′ma)
A glial neoplasm of the central nervous system, occurring typically in childhood; the prototype tumor cells resemble ependymoblasts. [ependymoblast + G. -oma, tumor]

ependymocyte (ep-en′di-mo-sit)
An ependymal cell. [ependyma + G. kytos, cell]

ependymoma (ep-en-di-mo′ma)
A glioma derived from relatively undifferentiated ependymal cells, comprising approximately 1–3% of all intracranial neoplasms; ependymomas occur in all age groups and may originate from the lining of any of the ventricles or, more commonly, from the central canal of the spinal cord; histologically, the neoplastic cells tend to be arranged radially about blood vessels, to which they are attached by means of fibrillary processes. myxopapillary e. a slow-growing e. of the filum terminale, occurring most often in young adults, consisting of cuboidal cells in papillary arrangement around a mucinous vascular core.

ephapse (ef′aps)
A place where two or more nerve cell processes (axons, dendrites) touch without forming a typical synaptic contact; some form of neural transmission may occur at such nonsynaptic contact sites. [G. ephapsis, contact]

ephaptic (e-fap′tik)
Relating to an ephapse.

ephebic (e-fe′bik)
Rarely used term relating to the period of puberty or to a youth. [G. ephebikos, relating to youth, fr. hebe, youth]

ephebology (ef-e-bol′o-je)
Rarely used term for the study of the morphologic and other changes incidental to puberty. [G. ephebos, puberty, + logos, study]

ephedra (e-fed′rah)
E. equisetina (family Gnetaceae). Ma Huang; the plant source for the alkaloid ephedrine. Indigenous to China and India, it is 0.75 to over 1% ephedrine; also contains some pseudoephedrine.

ephedrine (e-fed′rin, ef′e-drin)
An alkaloid from the leaves of Ephedra equisetina, E. sinica, and other species (family Gnetaceae), or produced synthetically; an adrenergic (sympathomimetic) agent with actions similar to those of epinephrine; used as a bronchodilator, mydriatic, pressor agent, and topical vasoconstrictor. Generally used salts are e. hydrochloride and e. sulfate.

ephelis, pl .ephelides (ef-e′lis, ef-e′li-dez)
SYN: freckle. [G.]

epi-
Upon, following, or subsequent to. [G.]

epi-coprostanol
5β-Cholestan-3α-ol. For the structure of cholestane, see steroids. SYN: e.coprosterol.

epi-coprosterol
SYN: e.coprostanol.

epiandrosterone (ep′i-an-dros′ter-on)
Inactive isomer (3β instead of 3α) of androsterone; found in urine and in testicular and ovarian tissue. SYN: isoandrosterone.

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