Action of Chronic Irradiation on the Cytogenetic Damage of Human Lymphocyte Culture

Abstract

Biophysics, Pushchino, Moscow Region, Russia The action of chronic irradiation (dose rate 2.9 Gy/day) on human lymphocyte culture was investigated. Whole blood was irradiated at 370C. Aliquots (0.2 ml) of whole blood were cultivated by the standard method. A medium containing phytohemagglutinin was added immediately after irradiation. All structural chromosome-and chromatid-type changes were recorded. The experimental data showed that the conditions of irradiation of lymphocytes affected neither the background level of chromosome damage nor their radiosensitivity. The obtained dose-response curve of chromosome aberrations was described by a linear regression, which then became a plateau. There is no statistically significant difference between the results for the low doses (10-50 cGy) of chronic and acute radiation.

Low Doses of Gamma-Radiation Induce Nonlinear Dose Responses in Mammalian and Plant Cells

“…Many years ago it was shown by Russel (1965) that the mutation yield per unit dose was higher at low doses of radiation than at high doses. Similar results were obtained by studying radiation-induced cytogenetic damage (Luchnik and Sevankaev, 1976;Pohl-Rulling et al, 1983;Lloyd et al, 1988;Zaichkina et al, 1997), transformation (Oftedal, 1990), and cell survival (Joiner, 1994;Joiner et al, 1996). Joiner et al (2001) showed that most cell lines have hyperradiosensitivity to very low radiation doses, which is not predicted by backextrapolation of the cell survival curve from higher doses.…”

“…All structural chromosometype and chromatid-type changes were recorded. Preliminary experiments showed that the conditions of blood-sample irradiation affected neither the background level of chromosomal damage nor radiosensitivity (Zaichkina et al, 1997).…”

“…Other blood samples were also chronically irradiated at a dose rate of 0.0061 Gy/h at a 37 • C temperature during 0.5, 1, and 2 days with cumulative doses of 0.07, 0.13, and 0.27 Gy, respectively. Whole blood (0.2 ml) was cultivated by the micromethod (Zaichkina et al, 1997). Cytogenetic analysis was carried out based on 150-200 metaphase cells scored from each blood sample.…”

Adaptation and Radiation-Induced Chromosomal Instability Studied by Statistical Modeling~!2009-12-10~!2010-02-20~!2010-03-30~!

“…The induction of genome instability by low-dose irradiation is well documented [9]. The study of genetic instability across generations of mice irradiated with low-dose-rate radiation indicates a genetic instability in the F1, F2, and F3 generations from irradiated males [53]. Our analysis of the structure of distributions of samples from persons living in settl.…”