| active formyl | The formyl group taking part in transformylation reactions with a folic acid derivative in the role of carrier. (05 Mar 2000) |
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| active immunity | <immunology> An organisms resistance to disease or infection, developed because the organisms immune system has produced antibodies after an infection or innoculation. (06 May 1997) |
| active immunization | The production of active immunity. (05 Mar 2000) |
| active inflammation | Any inflammation that has a fairly rapid onset, quickly becomes severe, usually manifested for only a few days, but may persist for several days or even a few weeks. Synonym: active inflammation. (05 Mar 2000) |
| active labour | Contractions resulting in progressive effacement and dilation of the cervix. (05 Mar 2000) |
| active length-tension curve | The relationship between active isometric tension and preload (rest length) for a contracting muscle. (05 Mar 2000) |
| active metal | <chemistry> Any very reactive metal, such as magnesium or sodium, most are located in the first two columns of the periodic table. (15 Jan 1998) |
| active methionine | S-(5'-deoxy-5'-adenosyl)-l-methionine;condensation product of adenosine and l-methionine involving replacement of the -OPO3H2 of adenylic acid by -S+ (CH3)CH2CH2CH(NH3+)CO 2 of methionine; a sulfonium compound bearing a methyl group that is transferred in transmethylation reactions. See: methionine adenosyltransferase. Synonym: active methionine. Acronym: SAM (05 Mar 2000) |
| active methyl | A methyl group attached to a quaternary ammonium ion or a tertiary sulfonium ion that can take part in transmethylation reactions; e.g., methyl groups in choline and in S-adenosyl-l-methionine, which are thus methyl donors. (05 Mar 2000) |
| active movement | Movement effected by the organism itself, unaided by external influences. (05 Mar 2000) |
| active mutant | A mutant with overt phenotypic expression. (05 Mar 2000) |
| active placebo | <pharmacology> Any dummy medical treatment, originally, a medicinal preparation having no specific pharmacological activity against the patients illness or complaint given solely for the psychophysiological effects of the treatment, more recently, a dummy treatment administered to the control group in a controlled clinical trial in order that the specific and non-specific effects of the experimental treatment can be distinguished i.e., the experimental treatment must produce better results than the placebo in order to be considered effective. (18 Nov 1997) |
| active principle | A constituent of a drug, usually an alkaloid or glycoside, upon the presence of which the characteristic therapeutic action of the substance largely depends. (05 Mar 2000) |
| active prophylaxis | Use of an antigenic (immunogenic) agent to actively stimulate the immunological mechanism. (05 Mar 2000) |
| active psychoanalysis | Psychoanalysis in which the analyst intervenes directly and actively in the patient's life, e.g., by making prohibitions, assigning tasks. (05 Mar 2000) |