| depressive reaction | 1. A lowering or decrease of functional activity. 2. <psychiatry> A mental state of depressed mood characterised by feelings of sadness, despair and discouragement. Depression ranges from normal feelings of the blues through dysthymia to major depression. It in many ways resembles the grief and mourning that follow bereavement, there are often feelings of low self esteem, guilt and self reproach, withdrawal from interpersonal contact and somatic symptoms such as eating and sleep disturbances. Origin: L. Depremere = to press down (18 Nov 1997) |
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| dermotuberculin reaction | A cutaneous tuberculin test. (05 Mar 2000) |
| detoxification reaction | Reactions taking place generally in the liver or kidney in order to inactivate toxins, either by degradation or else by conjugation of residues to a hydrophilic moiety to promote excretion. (18 Nov 1997) |
| 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) |
| digitonin reaction | The reaction of naturally occurring steroids with 3b-hydroxyl groups with digitonin, a steroid glycoside, resulting in the formation of an insoluble precipitate; useful in determining the presence of cholesterol and ergosterol. (05 Mar 2000) |
| Dische reaction | The assay of DNA by means of the blue colour formed with diphenylamine in acid (Dische reagent). (05 Mar 2000) |
| dissociative reaction | Reaction characterised by such dissociative behaviour as amnesia, fugues, sleepwalking, and dream states. (05 Mar 2000) |
| DNA-driven reaction | <molecular biology> A lab technique to mark highly-repeated DNA sequences with a radioactive RNA tracer, by having a much larger amount of complementary DNA molecules than radioactive RNA tracer molecules. (09 Oct 1997) |
| dopa reaction | A dark staining observed in fresh tissue sections to which a solution of dopa has been applied, presumably due to the presence of dopa oxidase in the protoplasm of certain cells. Synonym: Bloch's reaction. (05 Mar 2000) |
| id reaction | An allergic manifestation of candidiasis, the dermatophytoses, and other mycoses characterised by itching, vesicular lesions that appear in response to circulating antigens at sites that are often far distant from the primary fungal lesion itself. See: dermatophytid, -id. (05 Mar 2000) |
| dystonic reaction | <pharmacology> Prolonged muscle contractions that may cause twisting and repetitive movements or abnormal posture. May occur in the form of rhythmic jerks. Can be seen as a side effect from antipsychotic medications and drugs used in the treatment of Parkinson's disease. (27 Sep 1997) |
| immediate hypersensitivity reaction | An immune response mediated by antibody, usually IgE, which occurs within minutes after a second encounter with an antigen, resulting in the release of histamine and subsequent swelling and vasodilation. (05 Mar 2000) |
| immediate 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) |
| immune adherence reaction | A method for the detection of very small quantities of antibody in which the antigen-antibody-complement complex adheres to indicator cells, usually primate erythrocytes or nonprimate blood platelets. The reaction is dependent on the number of bound c3 molecules on the c3b receptor sites of the indicator cell. (12 Dec 1998) |
| immune reaction | Antigen-antibody reaction indicating a certain degree of resistance, usually in reference to the 36-to 48-hour reaction in vaccination against smallpox; because the degree of resistance indicated by the reaction is not true immunity and may disappear relatively rapidly there is a tendency to refer to the immune reaction as an allergic reaction. (05 Mar 2000) |