| irreversible reaction | A reaction or response by the tissues to a pathogenic agent characterised by a permanent pathologic change. (05 Mar 2000) |
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| oxidase reaction | The formation of indol blue when a blood smear containing myeloid leukocytes is treated with a mixture of alpha-naphthol and p-dimethylaniline sulfate; the myeloid leukocytes contain an oxidase that catalyses this reaction, the lymphoid leukocytes do not, in bacteriology, a reaction that depends on the presence of certain oxidases in some bacteria that catalyze the transport of electrons between electron donors in the bacteria and an oxidation reduction dye, such as tetramethyl-p-phenylenediamine; the dye is reduced to a blue or black colour. (05 Mar 2000) |
| oxidation-reduction reaction | <chemistry> Any reaction in which electrons are removed from one molecule or atom and given to another molecule or atom. (09 Oct 1997) |
| thermonuclear reaction | <radiobiology> See thermonuclear fusion, above. (09 Oct 1997) |
| thermoprecipitin reaction | The throwing down of a precipitate on the application of heat, as in the case of proteinaceous urine. (05 Mar 2000) |
| early reaction | Local or generalised response that begins within a few minutes to about an hour after exposure to an antigen to which the individual has been sensitised. See: skin test, wheal-and-erythema reaction. Synonym: early reaction. (05 Mar 2000) |
| echo reaction | A disorder of speech where there is an involuntary repetition several times of the same word. (27 Sep 1997) |
| Ehrlich reaction | The reaction of the indole derivatives with aromatic aldehydes; e.g., tryptophan and p-dimethylaminobenzaldehyde in H2SO4 give a red-violet colour useful in assaying proteins for tryptophan content. Synonym: Ehrlich reaction. (05 Mar 2000) |
| Ehrlich's benzaldehyde reaction | A test for urobilinogen in the urine, by dissolving 2 g of dimethyl-p-aminobenzaldehyde in 100 ml of 5% hydrochloric acid and adding this reagent to urine; a red colour in the cold indicates the presence of an excessive amount of urobilinogen. (05 Mar 2000) |
| Ehrlich's diazo reaction | The reaction of diazotised sulfanilic acid with bilirubin to form azobilirubin, which forms the basis of quantitating the amount of bilirubin in biological fluids. See: van den Bergh's test. Synonym: Ehrlich's diazo reaction. (05 Mar 2000) |
| transfusion reaction | A reaction to a blood transfusion secondary to some incompatibility in type, RH factor or other surface antigens. May be manifest by haemolytic anaemia, heart failure, and-or renal failure. Symptoms include facial flushing, angioedema, headache, wheezing, anaphylaxis, shock, fever, chills and breathing difficulty. (27 Sep 1997) |
| transplantation reaction | <immunology> The set of cellular phenomena observed after an allogeneic (mismatched) graft is made to an organism that leads to destruction, detachment or isolation of the graft. In mammals this includes the invasion and destruction of the graft by cytotoxic lymphocytes, inhibition of angiogenesis and other processes. (18 Nov 1997) |
| Treponema pallidum immobilization reaction | A test for syphilis in which an antibody other than Wassermann antibody is present in the serum of a syphilitic patient, which in the presence of complement causes the immobilization of actively motile Treponema pallidum obtained from testes of a rabbit infected with syphilis. Synonym: TPI test, Treponema pallidum immobilization reaction. (05 Mar 2000) |
| eosinopenic reaction | Reduction in the numbers of circulating eosinophils by ACTH or by adrenal corticoids. (05 Mar 2000) |
| triketohydrindene reaction | <technique> A technique for detecting amino acids and proteins by heating a material with ninhydrin, if amino molecules are present, there is a colour reaction. (09 Oct 1997) |