No abstract available

[en] Cells derived from individuals with ataxia-telangiectasia (A-T) are known to exhibit increased sensitivity to ionizing radiation and certain radiomimetic chemical agents. Here we summarize our findings regarding the role of chromosome damage and repair in this radiosensitivity. Lymphoblastoid cells derived from A-T homozygotes were characterized for initial chromosome (premature chromosome condensation) and DNA (neutral filter elution) damage and repair kinetics in cells from G1 and G2 cell cycle phases. Despite initial levels of DNA damage being similar to normal controls, A-T cells exhibited nearly a two-fold higher initial amount of chromosome damage. Different A-T cell lines exhibited differing chromosome repair capacities compared with control lymphoblastoid cell lines. These results suggest that A-T cells have an altered chromatin structure whereby DNA double-strand breaks are apparently more efficiently converted into chromosome breaks. (author)

[en] Individual variations in mammalian radiosensitivity have been discussed with particular emphasis to the relationship between individual sensitivity and regulatory functions. A concept on the contribution of efficiency variations of regulatory mechanisms to individual radioresistance has been proposed. The concept is based on the results demonstrating a relationship between individual radiosensitivity electrolytic function balance, adrenal cortex activation, serotonin release, and metabolic activity

[en] The present report is the third in a series dealing with dosimetric problems in radiotherapy. Its purpose is to define important volumes, areas and absorbed dose patterns and to recommend methods for specifying the absorbed dose in reports of treatments with external radiation beams. A subsidiary purpose of the present report, in addition to the specification of treatment volumes and absorbed doses, is therefore to make recommendations on the minimum requirements for reporting external beam therapy. These recommendations are intended to be applicable to most clinical situations, past or present, and to most radiotherapy centers. In some situations factors additional to those listed may be considered to have clinical implications and should therefore be reported as well

[en] The transfer of soluble Np(V) nitrate was measured in gastrointestinal segments from adult rats by instillation perfusion. These assays allowed accurate measurement of the Np(V) transferred from the intestine to the whole body. The amount measured was proportional to segment length and to the duration of the experiments, which lasted for periods of 0.25 to 2 h. Under these experimental conditions, hourly transfer values were about 2%, both per millilitre of Np(V) solution instilled and per 10 cm of jejunum perfused. This flux is very much greater than that which may be deduced from studies in which Np was gavaged into intact rats. Intestinal transfer of Np was constant for Np concentrations ranging from 5 x 10^-12 M to 1 x 10^-4 M. Raising the concentration of Np(V) to more than 1 x 10^-4 M reduced its intestinal transfer. Addition of Fe(II) also reduced it. The small intestine was the main site of Np(V) absorption, since the transfer from instilled jejunum was about 20 times that observed from the stomach, and no difference was noted between jejunal and duodenal transfer. (author)

[en] The author reviews the current state of knowledge of the role of hypoxia as a determinant factor in cancer radiotherapy, and concludes that it is reasonable to suppose that before treatment between one-third and one-half of breast, cervix and head and neck carcinomas contain radiobiologically hypoxic cells. The development of pO₂ measurements in human tumours together with more experimental data from biopsies and the search for relationships between measured pO₂ and the outcome of radiotherapy are called for. (UK)

[en] The incidence of adverse reactions to radiopharmaceuticals in nuclear medicine reported to the European Scheme during 1984-1986 together with details of the reporting mechanism used is given. The types of adverse reactions observed and the causative agents such as diphosphonates, colloids, albumin particulates and DTPA radiopharmaceuticals are discussed. A brief review is also given of drug/radiopharmaceutical incompatibilities under the headings of 1) unusual handling of the radiopharmaceuticals as a result of the pharmacological effect of the drug, 2) physicochemical interaction between the radiopharmaceutical and the drug and 3) drug-induced disease. (UK)

[en] The taktivin immune correction action on irradiated organism immune system is studied. There were two series of experiments with 50 animals in each serial. The intacted and irradiated animals served as control ones. Irradiated animals have got the taktivin course 1,5-2,0 μg each 1 kg of mass intraperitoneally, during 3 days. Under tactivin action the immunity's T-sells quality and quantitative ability has been increased, and the lymphoid cells in the bone morrow and thymus have been normalized, and its quantity in spleen and small intestine's lymph nodes have been rise. The activation of energetic exchange within spleen has being carried out

[en] Radiosensitization of hypoxic yeast cells (various strains of Saccharomyces cerevisiae) by oxygen and metronidazole was compared in wild-type and various X-ray radiosensitive mutants. The oxygen-enhancement ratio (o.e.r.) depended markedly on cell genotypes. Yeast strains which were deficient in ability to repair radiation damage had lower o.e.r. values than their more radioresistant parents. The relationship between o.e.r. and Dsub(o) was almost linear. Metronidazole was found to enhance radiosensitivity of hypoxic cells only of those strains that showed an o.e.r. more than 2.2. Some possible explanations of these effects are discussed

[en] Short communication