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Medical Dictionary


echinococcosis (e-ki′no-kok-ko′sis)
Infection with Echinococcus; larval infection is called hydatid disease. SYN: echinococciasis, echinococcus disease.

Echinococcus (e-ki′no-kok′us)
A genus of very small taeniid tapeworms, two to five segments in adult worms; adults are found in various carnivores but not in humans; larvae, in the form of hydatid cysts, are found in the liver and other organs of ruminants, pigs, horses, rodents, and, under certain epidemiologic circumstances, humans ( e.g., sheep herders living closely with their infected dogs). [echino- + G. kokkos, a berry] E. granulosus hydatid tapeworm, a species in which adults infect canids and the larval form (osseous and unilocular hydatid cysts) infects sheep and other ruminants, pigs, and horses; may also occur in humans, giving rise to a large cyst in the liver or other organs and tissues. E. multilocularis a north temperate and Arctic species of tapeworm that occurs, in the adult form, in foxes; the larva (alveolar hydatid cyst) is found in the liver of microtine rodents and in humans; it produces a proliferative, often slow-growing cyst in the liver that, in humans, is usually fatal. E. vogeli a species reported from humid tropical forests of Panama and northern South America causing a polycystic form of human hydatid disease intermediate between cystic and alveolar hydatid disease; the typical cycle involves domestic dogs and wild canids as host of the adult tapeworm, and rodents such as the paca (Cuniculus paca) as the intermediate host for the cystic form.

echinocyte (ek′i-no-sit)
A crenated red blood cell. [echino- + G. kytos, cell]

echinoderm (e-ki′no-derm)
A member of the phylum Echinodermata.

Echinodermata (e-ki-no-der′ma-ta)
A phylum of Metazoa that includes starfish, sea urchins, sea lilies, and other classes. All but the sea cucumbers (Holothuroidea) are basically radially symmetrical and most possess a calcareous endoskeleton with external spines. They inhabit the sea bottom, some near shore, others in deep water. [echino- + G. derma, skin]

Echinorhynchus (e-ki-no-ring′kus)
A genus of acanthocephalid (thorny-headed) worms which originally included species now contained in Macracanthorhynchus, Gigantorhynchus, and other genera. [echino- + G. rhynchos, snout]

echinosis (ek-i-no′sis)
A condition in which the red blood cells have lost their smooth outlines, resembling an echinus or sea urchin. [echino- + G. -osis, condition]

Echinostoma (e-ki-no-sto′ma, ek-i-nos′to-ma)
A genus of digenetic flukes (family Echinostomatidae) with characteristic oral spines; widely distributed and parasitic in a broad range of bird and mammal hosts; several species have been reported in humans from Southeast Asia. [echino- + G. stoma, mouth] E. ilocanum a species reported from humans in the Philippines. E. malayanum a species typically found in the pig, but reported occasionally from humans in Malaysia; infection results from ingestion of snails with infective cysts (metacercariae).

echinostomiasis (e-ki′no-sto-mi′a-sis)
Infection of birds and mammals, including humans, with trematodes of the genus Echinostoma.

echinulate (e-kin′u-lat)
Prickly or spinous. Covered with small spines. SYN: echinate. [Mod. L. echinulus, dim. of L. echinus, hedgehog]

Echis (ek′is, e′kis)
The saw-scaled or carpet viper, a genus of small (under 1 m), irritable, and alert snakes with a highly toxic venom; they are responsible for numerous snakebite cases with many fatalities. [G. e., a viper]

echo (ek′o)
1. A reverberating sound sometimes heard during auscultation of the chest. 2. In ultrasonography, the acoustic signal received from scattering or reflecting structures or the corresponding pattern of light on a CRT or ultrasonogram. 3. In magnetic resonance imaging, the signal detected following an inverting pulse. [G.] atrial e. electrical reactivation of the atrium by a retrograde impulse returning from the A-V node while the antegrade impulse continues to the ventricle; characterized electrocardiographically, by a pair of P waves enclosing a QRS complex, the second P wave being opposite in polarity (usually inverted in lead II), indicating that it is the reverse (the retrograde pathway) of the pathway of the first P wave (the antegrade pathway). navigator e. a method of respiratory gating q.v., used in magnetic resonance imaging to limit respiratory motion artifact; a signal is derived from the top of the diaphragm, and image data are collected only when it is in a selected range. nodus sinuatrialis e., NS e. a postectopic sinus beat occurring earlier than would be expected from the preceding sinus node discharge interval; i.e., the interval following a premature beat of supraventricular origin is less than the ordinary cycle length between sinus beats, whereas ordinarily the interval would be expected to exceed cycle length. e. planar a method of magnetic resonance imaging that allows rapid image acquisition during free induction decay, using technically demanding rapidly oscillating radiofrequency gradients. spin e. a commonly used technique to recover T1 and T2 relaxation signals in magnetic resonance imaging, by using a 180° inverting pulse in the pulse sequence to compensate for loss of transverse magnetization caused by magnetic field inhomogeneities.

echoacousia (ek′o-a-koo′ze-a)
A subjective disturbance of hearing in which a sound appears to be repeated. [echo + G. akouo, to hear]

echoaortography (ek′o-a-or-tog′ra-fe)
Application of ultrasound techniques to the diagnosis and study of the aorta. [echo + aortography]

echocardiogram (ek-o-kar′de-o-gram)
The record obtained by echocardiography. See ultrasonography.

echocardiography (ek′o-kar-de-og′ra-fe)
The use of ultrasound in the investigation of the heart and great vessels and diagnosis of cardiovascular lesions. SYN: ultrasonic cardiography, ultrasound cardiography. [echo + cardiography] contrast e. the injection of contrast media of high echo reflectants ( e.g., bubbles) to outline a chamber or delineate a shunt within the heart. cross-sectional e. SYN: two-dimensional e.. Doppler e. use of Doppler ultrasonography techniques to augment two-dimensional e. by allowing velocities to be registered within the echocardiographic image. See duplex ultrasonography, Doppler ultrasonography. M-mode e. See M-mode. real-time e. SYN: two-dimensional e.. sector e. two-dimensional e. with a stationary transducer. stress e. echocardiographic monitoring of a circulatory challenge, usually exercise. transesophageal e. recording of the echocardiogram from a transducer swallowed by the patient to predetermined distances in the esophagus and stomach. transthoracic e. the standard e. recorded from echocardiographic “windows” on the chest wall, jugular notch, or epigastrium. two-dimensional e. e. in which an image is reconstructed from the echoes stimulated and detected by a linear array or moving transducers. SYN: cross-sectional e., real-time e..

echoencephalography (ek′o-en-sef-a-log′ra-fe)
The use of reflected ultrasound in the diagnosis of intracranial processes. [echo + encephalography]

echo-free (ek′o-fre)
SYN: anechoic.

echogenic (ek-o-jen′ik)
Pertaining to a structure or medium ( e.g., tissue) that has internal echoes. Cf. hypoechoic, hyperechoic, and anechoic, which refer, respectively, to paucity, abundance, and absence of echoes displayed in the image of a structure.

echogram (ek′o-gram)
A record obtained using acoustic reflection techniques in any one of the various display modes, especially an echocardiogram. SEE ALSO: ultrasonogram. [echo + G. gramma, a diagram]

echographer (e-kog′ra-fer)
SYN: ultrasonographer.

echographia (ek-o-graf′e-a)
A form of agraphia in which one cannot write spontaneously, but can write from dictation or copy. [echo + G. grapho, to write]

echography (e-kog′ra-fe)
SYN: ultrasonography. [echo + G. grapho, to write]

echolalia (ek-o-la′le-a)
Involuntary parrotlike repetition of a word or sentence just spoken by another person. Usually seen with schizophrenia. SYN: echo reaction, echo speech, echophrasia. [echo + G. lalia, a form of speech]

echolocation (ek′o-lo-ka′shun)
Term applied to the method by which bats direct their flight and avoid solid objects. The creatures emit high-pitched cries that, though inaudible to human ears, are heard by the bats themselves as reflected sounds (echoes) from objects in their path.

echomotism (ek′o-mo′tizm)
SYN: echopraxia. [echo + L. motio, motion]

echopathy (e-kop′a-the)
A form of psychopathology, usually associated with schizophrenia, in which the words (echolalia) or actions (echopraxia) of another are imitated and repeated. [echo + G. pathos, suffering]

echophony, echophonia (e-kof′o-ne, ek-o-fo′ne-a)
A duplication of the voice sound occasionally heard during auscultation of the chest. [echo + G. phone, voice]

echophrasia (ek-o-fra′ze-a)
SYN: echolalia. [echo + phrasis, speech]

echopraxia (ek′o-prak′se-a)
Involuntary imitation of movements made by another. See echopathy. SYN: echomotism. [echo + G. praxis, action]

echoscope (ek′o-skop)
Instrument for displaying echoes by means of ultrasonic pulses on an oscilloscope to demonstrate structures lying at depths within the body. [echo + G. skopeo, to view]

echothiophate iodide (ek-o-thi′o-fat)
A potent organophosphorus compound and cholinesterase inhibitor, used in the eye in the treatment of glaucoma.

Echovirus 28 (ek′o-vi′rus)
Reclassified as Rhinovirus type 1.

echovirus (ek′o-vi-rus)
SYN: ECHO virus.

Nikolai V., Russian physiologist, 1849–1917. See E. fistula, reverse E. fistula.

Enrique Eduardo., U.S. bacteriologist, 1887–1966. See Rees-E. fluid.

Alexander, German anatomist, 1816–1887. See E. fissure.

eclabium (ek-la′be-um)
Eversion of a lip. [G. ek, out, + L. labium, lip]

eclampsia (ek-lamp′se-a)
Occurrence of one or more convulsions, not attributable to other cerebral conditions such as epilepsy or cerebral hemorrhage, in a patient with preeclampsia. [G. eklampsis, a shining forth] puerperal e. convulsions and coma associated with hypertension, edema, or proteinuria occurring in a woman following delivery. superimposed e. convulsions occuring in a woman with superimposed preeclampsia.

eclamptic (ek-lamp′tik)
Relating to eclampsia.

eclamptogenic, eclamptogenous (ek-lamp-to-jen′ik, -tog′e-nus)
Causing eclampsia.

eclectic (ek-lek′tik)
Picking out from different sources what appears to be the best or most desirable. [G. eklektikos, selecting, fr. ek, out, + lego, to select]

eclecticism (ek-lek′ti-sizm)
1. A now defunct system of medicine that advocated use of indigenous plants to effect specific cures of certain signs and symptoms. 2. A system of medicine practiced by ancient Greek and Roman physicians who were not affiliated with a medical sect but who adopted the practice and teachings that they considered best from other systems.

The environment. [G. oikos, house, household, habitation]

ecoendocrinology (e′ko-en′do-kri-nol′o-je)
The study of the interactions of endocrine systems with the environment.

Abbreviation for electrocorticography.

ecological fallacy
The bias that may occur because an association observed between variables at an aggregate level does not necessarily represent an association that exists at an individual level; an error of inference due to failure to distinguish between different levels of organization.

ecology (e-kol′o-je)
The branch of biology concerned with the total complex of interrelationships among living organisms, encompassing the relations of organisms to each other, to the environment, and to the entire energy balance within a given ecosystem. SYN: bioecology, bionomics (2) . [eco- + G. logos, study] human e. the relations of persons to their total (biologic and social) environment. landscape e. the study of the reciprocal effects of spatial pattern on ecologic processes.

econazole (e-kon′a-zol)
A broad spectrum antifungal agent used in the treatment of tinea pedis and related fungal infections.

See von E..

economy (e-kon′o-me)
System; the body regarded as an aggregate of functioning organs. [G. oikonomia, management of the house, fr. oikos, house, + nomos, usage, law]

ecospecies (e-ko-spe′shez)
Two or more populations of a species isolated by ecologic barriers, theoretically able to exchange genes and interbreed, but partially separated from one another by differences in habitat or behavior.

ecosystem (e′ko-sis-tem)
1. The fundamental unit in ecology, comprising the living organisms and the nonliving elements that interact in a defined region. 2. A biocenosis (biotic community) and its biotope. SYN: ecological system. parasite-host e. SYN: parasitocenose.

ecotaxis (e-ko-tak′sis)
Migration of lymphocytes “homing” from the thymus and bone marrow into tissues possessing an appropriate microenvironment. [eco- + G. taxis, order, arrangement]

écouvillon (a-koo-ve-yohn′)
A brush with firm bristles for freshening sores or abrading the interior of a cavity. [Fr., cleaning brush]

Abbreviation for eosinophil cationic protein.

ecphyma (ek-fi′ma)
A warty growth or protuberance. [G. a pimply eruption]

Abbreviation for electrocerebral silence.

ecstasy (ek′sta-se)
Mental exaltation, and/or a rapturous experience. [G. ekstasis, astonishment]

ecstatic (ek-stat′ik)
Relating to or marked by ecstasy.

ecstrophe (ek′stro-fe)
SYN: exstrophy.

Abbreviation for electroconvulsive therapy, electroshock therapy.

See ecto-.

ectad (ek′tad)
Outward. [G. ektos, outside, + L. ad, to]

ectal (ek′tal)
Outer; external. [G. ektos, outside]

ectasia, ectasis (ek-ta′ze-a, ek′ta-sis)
Dilation of a tubular structure. [G. ektasis, a stretching] annuloaortic e. supravalvular dilation of the aorta involving both its wall and the valve ring, which, however, remains of smaller diameter than the more distal ectatic wall; many cases are related to Marfan syndrome. SYN: aortoannular e.. aortoannular e. SYN: annuloaortic e.. e. cordis dilation of the heart. corneal e. SYN: keratoectasia. diffuse arterial e. spontaneous enlargement with dilation of the vessels. familial aortic e. (ek′ta-ze-a) SYN: familial aortic e. syndrome. hypostatic e. dilation of a blood vessel, usually a vein, in a dependent portion of the body, as in varicose veins of the leg. mammary duct e. dilation of mammary ducts by lipid and cellular debris in older women; rupture of ducts may result in granulomatous inflammation and infiltration by plasma cells. SEE ALSO: plasma cell mastitis. scleral e. SYN: sclerectasia. e. ventriculi paradoxa SYN: hourglass stomach.

-ectasia, -ectasis
Dilation, expansion. [G. ektasis, a stretching]

ectatic (ek-tat′ik)
Relating to, or marked by, ectasis.


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