[DNA degradation during radiation death of cultured cells]

The method of flow cytofluorometry was used to study postirradiation changes in plasma membrane permeability and DNA content of the Burkitt's lymphoma cells (Raji line). At a dose of 10 Gy, the increase in membrane permeability preceded the appearance of cells with diminished DNA content. The synchronization of cells in phase G2 was associated with a virtually complete radiation arrest of mitoses. The postirradiation electrophoretic analysis of DNA of the Burkitt's lymphoma cells and of Syrian and Chinese hamster fibroblasts showed that the DNA degradation is unordered and results perhaps from activation of hydrolases in the dead cells.