| modified radical mastectomy | <procedure, surgery> The most common type of mastectomy. Breast skin, nipple, areola and underarm lymph nodes are removed. The chest muscles are saved. (09 Oct 1997) |
|---|---|
| colour radical | The part of a visibly coloured molecule responsible for light absorption over a range of wavelengths thus giving rise to the colour. By extension the term may be applied to UV or IR absorbing parts of molecules. Do not confuse with chromatophores. (18 Nov 1997) |
| hydroxyl radical | <chemical> Hydroxyl. The univalent radical oh. This radical is characteristic of hydroxides, oxygen acids, alcohols, glycols, phenols, and hemiacetals. Chemical name: Hydroxyl (12 Dec 1998) |
| oxygen radical | <chemistry> Any oxygen species that carries an unpaired electron (except free oxygen). Examples are the hydroxyl radical and the superoxide anion. These radicals are very powerful oxidizing agents and cause structural damage to proteins and nucleic acids. They mediate the damaging effects of ionising radiation. (18 Nov 1997) |
| extended radical mastectomy | Excision of the entire breast including the nipple, areola, and overlying skin, as well as the pectoral muscles and the lymphatic-bearing tissues of the axilla and chest wall and internal mammary chain of lymph nodes. (05 Mar 2000) |
| free radical | A chemically active atom or molecular fragment containing a chemical charge due to an excess or deficient number of electrons. Radicals seek to receive or release electrons in order to achieve a more stable configuration, a process that can damage the large molecules within cells. See: Oxidation. (09 Oct 1997) |
| free radical reductase | <enzyme> Catalyses conversion of carbon-centreed lipid radicals into an inactive species by utilizing vitamin e at one end and glutathione at the other Registry number: EC 1.8.4.- (26 Jun 1999) |
| free radical scavengers | Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries. (12 Dec 1998) |
| Rambourg's chromic acid-phosphotungstic acid stain | <technique> A stain for glycoproteins, used with an electron microscope, with which ultrathin tissue sections reveal complex carbohydrates in the same locations as shown by Rambourg's periodic acid-chromic methenamine-silver stain. (05 Mar 2000) |
| a1-acid glycoprotein | <biology> Plasma protein of mammals and birds, 38% carbohydrate. In humans a single chain glycoprotein of 39 kD. Increased levels are associated with inflammation, pregnancy and various diseases. (18 Nov 1997) |
| abscisic acid | <biochemistry> A lipid hormone that inhibits cell growth in plants, it is associated with fruit drop, leaf death and seed dormancy. It is synthesised in the plastids from carotenoids. This hormone helps plants deal with water loss, and its effects can be reversed with gibberellins. (06 May 1997) |
| abscisic acid 8'-hydroxylase | <enzyme> Catalyses conversion of abscisic acid to 8'-hydroxyabscisic acid, which rearranges to phaseic acid Registry number: EC 1.14.99.- Synonym: aba 8'-hydroxylase (26 Jun 1999) |
| acetic acid | <chemical> The acid most commonly associated with vinegar, it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and Acetobacter but, except for making vinegar, is usually made through synthetic processes. Derivatives of acetic acid which may be formed by substitution reactions. Mono- and di-substituted, as well as, halogenated compounds have been synthesised. Experimentally, alpha- and n2- substituted acetic acids have been examined for their anti-inflammatory activity and effect on the central nervous system respectively. Additionally, limited exposure data has been collected on dibromo and dichloroacetic acids to determine whether they pose health effects. Synonym: ethanoic acid. (26 Jun 1999) |
| acetoacetic acid | CH3COCH2COOH;one of the ketone bodies, formed in excess and appearing in the urine in starvation or diabetes. Synonym: diacetic acid. (05 Mar 2000) |
| acetohydroxamic acid | C2H5NO2; N-Hydroxyacetamide;an inhibitor of urease, used as adjunctive therapy in chronic urea-splitting urinary infections. (05 Mar 2000) |