| declamping phenomenon | Shock or hypotension following abrupt release of clamps from a large portion of the vascular bed, as from the aorta; apparently caused by transient pooling of blood in a previously ischemic area. Synonym: declamping shock. (05 Mar 2000) |
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| deja vu phenomenon | The mental impression that a new experience (e.g., a scene, sight, sound, or action) has happened before; a common phenomenon in normal persons that may occur more frequently or continuously in certain emotional or organic disorders. Also variously referred to as deja entendu, deja eprouve, deja fait, deja pense, deja raconte, deja vecu, or deja voulu, depending on the experience or sense that is evoked. (05 Mar 2000) |
| Dejerine-Lichtheim phenomenon | <clinical sign> In subcortical aphasia, the patient can indicate by use of the fingers the number of syllables of a word he has in mind but cannot speak. Synonym: Dejerine-Lichtheim phenomenon. (05 Mar 2000) |
| Dejerine's hand phenomenon | Clonic contractions of the flexors of the hand (wrist) on tapping the dorsum of the hand or the volar side of the forearm near the wrist; occurs in normal persons but is exaggerated in pyramidal tract lesions. Synonym: Dejerine's reflex. (05 Mar 2000) |
| symbiotic fermentation phenomenon | "two organisms, neither of which alone produces gas fermentation in certain carbohydrates, may do so when living in symbiosis or when artificially mixed" (Castellani). (05 Mar 2000) |
| Denys-Leclef phenomenon | Enhanced phagocytosis by leukocytes of microorganisms in the presence of immune serum. (05 Mar 2000) |
| d'Herelle phenomenon | The lysis of bacteria by bacteriophage. Synonym: bacteriophagia, d'Herelle phenomenon, Twort phenomenon. (05 Mar 2000) |
| dip phenomenon | Complete disappearance of ventricular excitability followed by progressive recovery within a few microseconds at the end of excitation; the muscle as a whole repolarises somewhat inhomogeneously, so that this period is one of special sensitivity to exogenous or endogenous stimuli and reentry. (05 Mar 2000) |
| Donath-Landsteiner phenomenon | The haemolysis which results in a sample of blood of a subject of paroxysmal haemoglobinuria when the sample is cooled to around 5캜 and then warmed again. (05 Mar 2000) |
| Doppler phenomenon | <radiobiology> Variation in the frequency of a wave (as measured by an observer) due to relative motion between the observer and the source of the wave. (The observed frequency increases if the source is moving towards the observer and vice versa.) The equation can be found in most optics texts and many introductory physics texts. (09 Oct 1997) |
| Duckworth's phenomenon | Respiratory arrest before cardiac arrest as a result of intracranial disease. (05 Mar 2000) |
| immune adherence phenomenon | A phenomenon manifested by the adherence of antigen-antibody-complement complex to "indicator cells" (microorganisms, platelets, leukocytes, or erythrocytes), the reaction being sensitive and specific for the antigen and antibody in the complex. Synonym: erythrocyte adherence phenomenon, immune adherence phenomenon, red cell adherence phenomenon. (05 Mar 2000) |
| quellung phenomenon | Increase in opacity and visibility of the capsule of capsulated organisms exposed to specific agglutinating anticapsular antibodies. Synonym: Neufeld reaction, quellung phenomenon, quellung reaction, quellung test. Scrotal swelling, the swelling formed after the embryonic genital swellings have fused together, become spherical, and migrated caudally to the base of the penis; just before birth the testis comes to lie within it. Spielmeyer's acute swelling, a form of degeneration of nerve cells in which the cell body and its processes swell and stain palely and diffusely. (05 Mar 2000) |
| on-off phenomenon | A state in the treatment of Parkinson's disease by l-dopa, in which there is a rapid fluctuation of akinetic (off) and choreoathetotic (on) movements. (05 Mar 2000) |
| orbicularis phenomenon | A constriction of both pupils when an effort is made to close eyelids forcibly held apart. A variant of the pupil response to near vision. Synonym: Galassi's pupillary phenomenon, Gifford's reflex, lid-closure reaction, orbicularis phenomenon, orbicularis pupillary reflex, Piltz sign, Westphal's pupillary reflex, Westphal-Piltz phenomenon. (05 Mar 2000) |