| capsular precipitation reaction | Swelling of the capsule surrounding a bacterium as a result of interaction with anticapsular antibody, consequently the capsule becomes more refractile and conspicuous. (18 Nov 1997) |
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| ammonium sulphate precipitation | <technique> In this technique, ammonium sulphate is used to make proteins precipitate out of a solution, the proteins are then collected by centrifugation. (09 Oct 1997) |
| precipitation | The act or process of precipitating. Origin: L. Praecipitatio (18 Nov 1997) |
| precipitation curve | A graph of the quantity of precipitate formed as a function of the quantity of antigen added during the titration of an antibody with an antigen. Synonym: Heidelberger curve. (05 Mar 2000) |
| precipitation test | An in vitro test in which antigen is in soluble form and precipitates when it combines with added specific antibody in the presence of an electrolyte. See: gel diffusion precipitin tests, ring precipitin test. Synonym: precipitation test. (05 Mar 2000) |
| hapten inhibition of precipitation | Inhibition of precipitation that occurs when the precipitin has combined with hapten of the same specificity as the subsequently added antigen. (05 Mar 2000) |
| double antibody precipitation | A method of separating antibody-bound antigen (e.g., insulin) from free antigen by precipitating the former with antibody specific for immunoglobulin. Synonym: double antibody immunoassay, double antibody method. (05 Mar 2000) |
| immune precipitation | <immunology> The precipitation of a multivalent antigen by a bivalent antibody, resulting in the formation of a large complex. The antibody and antigen must be soluble. Precipitation usually occurs when there is near equivalence between antibody and antigen concentrations. (18 Nov 1997) |
| isopropanol precipitation test | A test using the principle that the internal bonds of haemoglobin are weakened by nonpolar solvents; thus, unstable haemoglobins will precipitate more rapidly than other haemoglobins in isopropanol. (05 Mar 2000) |
| 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) |