| haematoporphyrin derivative | <chemical> A complex mixture of monomeric and aggregated porphyrins used in the photodynamic therapy of tumours (haematoporphyrin photoradiation). A purified component of this mixture is known as dihematoporphyrin ether. Pharmacological action: antineoplastic agent, photosensitizing agents. Chemical name: Haematoporphyrin D (12 Dec 1998) |
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| purified protein derivative of tuberculin | Purified tuberculin containing the active protein fraction; the tuberculin from which it is prepared differs from tuberculin chiefly in that the bacteria are grown in a synthetic rather than in a broth medium. (05 Mar 2000) |
| derivative | A chemical substance derived from another substance either directly or by modification or partial substitution. (18 Nov 1997) |
| derivative chromosome | An anomalous chromosome generated by translocation. Synonym: translocation chromosome. (05 Mar 2000) |
| radioactive isotope | <physics, radiobiology> An isotope of an element that has an unstable nucleus, it tries to stabilise itself by giving off ionising radiation. (09 Oct 1997) |
| stable isotope | A nonradioactive nuclide; an isotope that shows no tendency to undergo radioactive decomposition. (05 Mar 2000) |
| daughter isotope | An element produced by radioactive decay of another. See: radionuclide generator, cow. (05 Mar 2000) |
| isotope | <radiobiology> One of several nuclides having the same number of protons in their nuclei and hence having the same atomic number, but differing in the number of neutrons and therefore, in the mass number. Almost identical chemical properties exist between isotopes of a particular element. The use of this term as a synonym for nuclide is to be discouraged. (16 Dec 1997) |
| isotope clearance | The rate at which an isotope is removed (usually by blood flow) from a tissue or organ such as the brain. (05 Mar 2000) |
| isotope labeling | Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labelled substances unless the methods of labeling are substantively discussed. Tracers that may be labelled include chemical substances, cells, or microorganisms. (12 Dec 1998) |
| Abbott's method | A method of treatment of scoliosis by use of a series of plaster jackets applied after partial correction of the curvature by external force. (05 Mar 2000) |
| Abell-Kendall method | A standard method for estimation of total serum cholesterol involving saponification of cholesterol ester by hydroxide, extraction with petroleum ether, and colour development with acetic anhydride-sulfuric acid; the method avoids interference by bilirubin, protein, and haemoglobin. (05 Mar 2000) |
| activated sludge method | A method of sewage disposal in which the sewage is treated with 15% bacterially active, liquid sludge, which is produced by repeated vigorous aeration of fresh sewage to form floccules or sediment; when this flocculation process is complete, the resulting activated sludge contains large numbers of bacteria, together with yeasts, molds, and protozoa, which actively effect the oxidation of organic compounds; this mixture is piped to a sedimentation tank, the effluent from which is completely treated sewage. (05 Mar 2000) |
| Altmann-Gersh method | The method of rapidly freezing a tissue and dehydrating it in a vacuum. (05 Mar 2000) |
| Anel's method | Ligation of an artery immediately above (on the proximal side of) an aneurysm. (05 Mar 2000) |