| vari | <zoology> The ringtailed lemur (Lemur catta) of Madagascar. Its long tail is annulated with black and white. Origin: Cf. F. Vari. Source: Websters Dictionary (01 Mar 1998) |
|---|---|
| variability | The state of being variable. (18 Nov 1997) |
| variable | One of a battery of antigenicdeterminants expressed by a microorganismto elude immune detection. (09 Oct 1997) |
| variable antigen | <immunology> Term usually applied to the surface antigens of those parasitic or pathogenic organisms that can alter their antigenic character to evade host immune responses. (See antigenic variation). (18 Nov 1997) |
| variable deceleration | Transient foetal bradycardia usually denoting compression of the umbilical cord which may occur at any time in relation to a uterine contraction. (05 Mar 2000) |
| variable gene | <molecular biology> Those regions in the amino acid sequence of both the heavy and the light chains of immunoglobulins where there is considerable sequence variability from one immunoglobulin to other of the same class, in contrast to constant sequence (C) regions. The V regions are associated with the antigen binding areas. They contain hypervariable regions of particularly high sequence diversity. (18 Nov 1997) |
| variable region | <molecular biology> Those regions in the amino acid sequence of both the heavy and the light chains of immunoglobulins where there is considerable sequence variability from one immunoglobulin to other of the same class, in contrast to constant sequence (C) regions. The V regions are associated with the antigen binding areas. They contain hypervariable regions of particularly high sequence diversity. (18 Nov 1997) |
| variable surface glycoprotein | <protein> One of a battery of antigenicdeterminants expressed by a microorganism to elude immune detection. (09 Oct 1997) |
| variance | 1. The state of being variable, different, divergent, or deviate; a degree of deviation. 2. A measure of the variation shown by a set of observations, defined as the sum of squares of deviations from the mean, divided by the number of degrees of freedom in the set of observations. (05 Mar 2000) |
| variance ratio | The distribution of the ratio of two independent estimates of the same variance from a gaussian distribution based on samples of sizes (n + 1) and (m + 1) respectively. Estimates are usually based on one such sample analyzed in such a way as to make them independent e.g., analysis of variance; and F may be used to test a null hypothesis that the observed differences among sample means is no greater than could readily be accounted for by chance. (05 Mar 2000) |
| variant | Something which differs in form from another thing, though really the same; as, a variant from a type in natural history; a variant of a story or a word. Origin: Cf. F. Variante. Source: Websters Dictionary (01 Mar 1998) |
| variant angina | A sudden vasoconstriction of a coronary artery depriving the myocardium of blood flow and oxygen. This may clinically manifest as chest pain referred to as variant angina or Printzmetal's angina. May be precipitated by emotional stress, medications, street drugs (cocaine) or on exposure to cold. Treatment includes nitroglycerin or beta-blocker medications. (27 Sep 1997) |
| variant angina pectoris | A form of angina pectoris, characterised by pain that is not precipitated by cardiac work, is of longer duration, is usually more severe, and is associated with unusual electrocardiographic manifestations including elevated ST segments in leads that are ordinarily depressed in typical angina, and usually without reciprocal ST changes; occurring at night in bed. Synonym: angina inversa, variant angina pectoris. (05 Mar 2000) |
| variant haemoglobin | A harmless mutant form of Hb. (05 Mar 2000) |
| variant surface glycoproteins, trypanosoma | Glycoproteins attached to the surface coat of the trypanosome. Many of these glycoproteins show amino acid sequence diversity expressed as antigenic variations. This continuous development of antigenically distinct variants in the course of infection ensures that some trypanosomes always survive the development of immune response to propagate the infection. (12 Dec 1998) |