Reproductive and interphase death after X-ray microirradiation of hamster ovary fibroblasts

Analysis of a total of 82 genealogical trees of irradiated cells and 75 genealogical trees of non-irradiated control cells revealed the following results: 1) For a damage fraction of 50% in comparison with the irradiation of cell populations. Single cell irradiation results in dose multiplication factors of 10 for the r- and of 27 for the s-death. 2) Up to date, a definite topological distinction between r- and s-damage is not possible. 3) The s-damage is strongly dependent on the size of the region directless around the irradiated point. 4) The r-1-death is closely connected with the formation of giant cells and multiple divisions and already incurs in cell nucleus irradiation. The following conclusions could be drawn from these results, in consideration of recent literature: 1) r- and s-damage are independent from each other; 2) For r1-and rsub(n)-damage, different damaging mechanisms are likely. (orig./AJ)