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[en] The theory underlying radiation protection was developed from studies of people, laboratory animals, tissues, cells and macromolecules. Data on people were obtained from opportunistic studies of individuals previously exposed to radiation. Rarely has it been possible to conduct prospective studies of people exposed to known quantities of radiation, which sharply restricts the nature of questions that they can address. In contrast, studies using laboratory animals and simpler biological systems can be designed to address specific questions, using controlled exposure conditions. In-vitro research with macromolecules, cells and tissues leads to understanding normal and disease processes in isolated biological components. Studies of the intact animals provide opportunities to study in vivo interactive mechanisms observed in vitro and their role in development of radiation-induced diseases such as cancer. In the future, studies of intact animals should prove increasingly valuable in linking new knowledge at the subanimal level with the more fragmentary information obtained from direct observations on people. This will provide insight into important issues such as (a) effects of low-level radiation exposures, (b) mechanism of cancer induction at high versus low radiation doses, and (c) influence of factors such as nutrition and exposure to chemicals on radiation-induced cancer. This presentation describes strategies for conducting and integrating results of research using macromolecules, cells, tissues, laboratory animals and people to improve our understanding of radiation-induced cancer. It will also emphasize the problems encountered in studies at all levels of biological organization when the disease is observed in low excess incidence long after exposure to the toxicant

[en] A comparison is made between the mutagenic effects of various chemicals (mutagens) and ionizing radiation. The following topics are included in the discussion; differences between the effects of chemicals and irradiation; relationship between mutations and chromosome aberrations; specificity; dose effect relationships; and the mutation spectrum

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[en] Physical efficiency and factors affecting it for persons exposed to irradiation (the radiation dose being in the range up to 0.75 Gy) has been studied. 670 participants of liquidating the consequences of ChNPP accident have been examined. Depending on the radiation doses to which the people have been exposed the liquidators have been subdivided into 4 groups: for the 1st group the radiation doses ranging from 0.25 to 0.75 Gy; for the 2nd group the radiation doses ranging from 0.10 to 0.24 Gy; for the 3rd group the radiation doses ranging from 0.05 to 0.10 Gy; for the 4th group the radiation dose being up to 0.05 Gy. The physical load was ensured with veloergometer. The results have made it possible to estimate one of the basic health criterion for liquidators of consequences of ChNPP accident (i.e. exercise (effort) tolerance). No direct relationship of the exercise magnitude and the radiation dose within the range up to 0.75 Gy and the irradiation time have been observed. The correlation of the exercise magnitude with due account to age has been provided. 15 refs.; 2 tabs

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[en] Short communication

[en] The increasing use of combined radiation, chemotherapy, and surgery has led to an increased incidence of acute and late complications. The complications are, in general, similar to those seen with each modality alone, but occur with increased incidence. Enhanced effects of combined radiation and surgery are modest in number and consist primarily of problems with wound healing and fibrosis, as well as late gastrointestinal damage. Combinations of radiotherapy and chemotherapy have shown a greater degree of enhanced acute and late reactions. Drugs, such as actinomycin-D and Adriamycin, are particularly dangerous if the marked enhancement of radiation effects caused by the drugs in almost all organs is not appreciated and the radiation dose not adjusted accordingly. Proper selection of drugs can lead to enhanced local control by radiotherapy and/or surgery, as well as eradication of microscopic distant metastases, without increased normal tissue injury. Late induction of malignancy can occur with either radiation or chemotherapy alone and, in some cases, this appears to be enhanced when they are combined

[en] The report evaluates the draft report with respect to the scientific considerations underlying the establishment of radioepidemiological tables to be used to determine the probability that given cancers occurring in people with previous radiation exposure have been caused by such exposure