| anaphylactic reaction | <immunology> A serious, often life-threatening allergic reaction that is characterised by low blood pressure, shock (poor tissue perfusion) and difficulty breathing. (27 Sep 1997) |
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| anaphylactic shock | <immunology> A serious, often life-threatening allergic reaction that is characterised by low blood pressure, shock (poor tissue perfusion) and difficulty breathing. (27 Sep 1997) |
| anaphylactogen | A substance (antigen) capable of rendering an individual susceptible to anaphylaxis; a substance (antigen) that will cause an anaphylactic reaction in such a sensitised individual. (05 Mar 2000) |
| anaphylactogenesis | <immunology> The process of causing or creating anaphylactic shock. (09 Oct 1997) |
| anaphylactogenic | Producing anaphylaxis; pertaining to substances (antigens) that result in an individual becoming susceptible to anaphylaxis. (05 Mar 2000) |
| anaphylactoid | <immunology> Resembling anaphylaxis, an immediate, transient allergic reaction. (09 Oct 1997) |
| anaphylactoid crisis | A reaction that is similar to anaphylactic shock, but which does not require the incubation period characteristic of induced sensitivity (anaphylaxis); it is unrelated to antigen-antibody reactions. Synonym: anaphylactoid crisis, pseudoanaphylactic shock. (05 Mar 2000) |
| anaphylactoid purpura | <dermatology> This relatively rare disorder is characterised by skin purpura, joint pains, abdominal pain and renal disease (glomerulonephritis). Although Henoch-Schonlein purpura or anaphylactoid purpura, is thought to be a immune complex mediated disease, its exact cause is unknown. Its typical benign coarse can, however, include renal failure. (27 Sep 1997) |
| anaphylactoid shock | A reaction that is similar to anaphylactic shock, but which does not require the incubation period characteristic of induced sensitivity (anaphylaxis); it is unrelated to antigen-antibody reactions. Synonym: anaphylactoid crisis, pseudoanaphylactic shock. (05 Mar 2000) |
| anaphylatoxin | <protein> Originally used as an antigen that reacted with an IgE antibody thus precipitating reactions of anaphylaxis. Now restricted to defining a property of complement fragments C3a and C5a, both of which bind to the surfaces of mast cells and basophils and cause the release of inflammatory mediators. (18 Nov 1997) |
| anaphylatoxin inactivator | An alpha-globulin (MW 300,000) which destroys the activity of the anaphylatoxic complement fragments. See: anaphylatoxin. (05 Mar 2000) |
| anaphylatoxins | The family of peptides c3a, c4a, c5a, and c5a des-arginine produced in the serum during complement activation. They produce smooth muscle contraction, mast cell histamine release, affect platelet aggregation, and act as mediators of the local inflammatory process. The order of anaphylatoxin activity from strongest to weakest is c5a, c3a, c4a, and c5a des-arginine. The latter is the so-called "classical" anaphylatoxin but shows no spasmogenic activity though it contains some chemotactic ability. (12 Dec 1998) |
| anaphylaxis | <pharmacology> As opposed to prophylaxis. A system or treatment that leads to damaging effects on the organism. <immunology> Now reserved for those inflammatory reactions resulting from combination of a soluble antigen with IgE bound to a mast cell that leads to degranulation of the mast cell and release of histamine and histamine like substances, causing localised or global immune reponses. Results in an acute allergic reaction with shortness of breath, rash, wheezing, hypotension. See: hypersensitivity. (18 Nov 1997) |
| anaphylotoxin | <protein> A substance which stimulates the release of histamines (which causes tissue inflammation) as part of an immunological response toward a foreign antigen.This can lead to anaphylactic shock. (09 Oct 1997) |
| anaplasia | <pathology, oncology> Characteristics of a cell (structure and orientation) that make it identifiable as a cancer cell and malignant. There is lack of differentiation, which is characteristic of some tumour cells. Origin: Gr. Plassein = to form (16 Dec 1997) |