| Shwartzman reaction | <investigation> Reaction that occurs when two injections of endotoxin are given to the same animal, particularly rabbits, 24h apart. In the local Shwartzman reaction the first injection is given intradermally, the second intravenously and a haemorrhagic reaction develops at the dermal site. If both injections are intravenous the result is a generalised Shwartzman reaction, often accompanied by disseminated intravascular coagulation. The reaction depends upon the response of platelets and neutrophils to endotoxin. (18 Nov 1997) |
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| generalised Shwartzman phenomenon | When both the primary injection of endotoxin-containing filtrate and the secondary injection are given intravenously 24 hours apart, the animal usually dies within 24 hours after the second inoculation; the characteristic lesions in the rabbit include widespread haemorrhages in the lung, liver, and other organs and bilateral cortical necrosis of the kidney. This reaction has no immunological basis. Synonym: Sanarelli phenomenon, Sanarelli-Shwartzman phenomenon. (05 Mar 2000) |
| Sanarelli-Shwartzman phenomenon | When both the primary injection of endotoxin-containing filtrate and the secondary injection are given intravenously 24 hours apart, the animal usually dies within 24 hours after the second inoculation; the characteristic lesions in the rabbit include widespread haemorrhages in the lung, liver, and other organs and bilateral cortical necrosis of the kidney. This reaction has no immunological basis. Synonym: Sanarelli phenomenon, Sanarelli-Shwartzman phenomenon. (05 Mar 2000) |
| Shwartzman, Gregory | <person> Russian bacteriologist in U.S., 1896-1965. See: Shwartzman phenomenon, Shwartzman reaction, generalised Shwartzman phenomenon, Sanarelli-Shwartzman phenomenon. (05 Mar 2000) |
| shwartzman phenomenon | A two-stage reaction in which a first encounter with endotoxin produces intravascular fibrin thrombi whose clearance results in reticuloendothelial blockade which prevents the clearance of thrombi caused by a second encounter with endotoxin, resulting in tissue necrosis and/or haemorrhage. In pregnancy gram-negative septicaemia during delivery or abortion may serve as the first or provocative encounter. The phenomenon is non-immunologic and is known to occur only in rabbits and man. (12 Dec 1998) |
| accelerated reaction | A response occurring in a shorter time than expected; the cutaneous manifestations occurring during the period between the second and tenth day following smallpox vaccination; because it is intermediate between a primary reaction and an immediate reaction, it is regarded as evidence of some degree of resistance. Synonym: vaccinoid reaction. (05 Mar 2000) |
| acid reaction | Any test by which an acid reaction is recognised such as the change of blue litmus paper to red, an excess of hydrogen ions over hydroxide ions in aqueous solution indicated by a pH value less than 7 (at 22캜). Compare: dissociation constant of water. (05 Mar 2000) |
| acute-phase reaction | <immunology, rheumatology> Refers to the changes in synthesis of certain proteins within the serum during an inflammatory response, which provides rapid protection for the host against microorganisms via non-specific defense mechanisms. It consists of fever, an increase in inflammatory humoral factors, and an increased synthesis by hepatocytes of a number of proteins or glycoproteins usually found in the plasma; the reaction is mediated by endogenous pyrogens, the hypothalamus, adrenal hormones, and other factors. (12 Jul 2000) |
| acute situational reaction | An acute emotional reaction related to extreme environmental stress. Synonym: acute situational reaction. (05 Mar 2000) |
| acute stress reaction | A sudden bout of anxiety that is often accompanied by the features of hyperventilation (tingling around mouth and in fingertips, rapid breathing, faintness or fainting). (27 Sep 1997) |
| addition reaction | <chemistry> Any reaction in which two chemicals combine to form a single chemical. (15 Jan 1998) |
| adverse drug reaction reporting systems | Systems developed for collecting reports from government agencies, manufacturers, hospitals, physicians, and other sources on adverse drug reactions. (12 Dec 1998) |
| adverse reaction | Any undesirable or unwanted consequence of a preventive, diagnostic, or therapeutic procedure or regimen. (05 Mar 2000) |
| agar-gel reaction | <immunology> The reaction between an antibody and an antigen during an immunology lab procedure where the two are allowed to diffuse toward each other through an agar-gel medium. Lines of precipitation form in the places on the gel where the two react with each other and shows where the reaction has occurred. (09 Oct 1997) |
| alarm reaction | The various phenomena, e.g., stimulated endocrine activity, which the body exhibits as an adaptive response to injury or stress; first phase of the general adaptation syndrome. (05 Mar 2000) |