[Chromosome aberrations in human peripheral blood lymphocytes after single and split-dose x-irradiation].

Effects of single exposures to 125 or 250 R and those of fractionated irradiations of 2.125 R on human lymphocytes were studied upon the chromosome aberration yields in blood maintained in a refrigerator at 5 degrees C for the intervals between the irradiations. Single irradiations succeeded venepuncture; the same holds for the first dose from the fractionated one, while he second was delivered at one of the following intervals: 2.8 or 24 hours. Immediately after completion of irradiation, blood was cultured to obtain metaphase slides for cytogenetic analysis. No repair processes were observed in the hereditary cell structures of fractionatedly irradiated blood if it was maintained at 5 degrees C for the intervals between irradiations. More chromosomes fragments, interstitial deletions, aberrant cells, and breakage of cells were scored, on the opposite, in fractionatedly irradiated blood, which was stored for 24 hours. These were even with high statistically significant differences when compared with singly exposed cells to the same doses. This effect was likely to be due to blood stirage.