MECHANISMS IN SHOULDERED SURVIVAL CURVES

电离辐射损伤哺乳动物细胞DNA的修复 对细胞存活至关重要。 哺乳动物细胞辐射存活的肩膀 曲线可以通过调用修复过程的饱和度来解释， 更高剂量 为了探究这一假设，需要对损伤进行分析 其可以在低辐射剂量下使用（在肩部内）， 高辐射剂量。 本文提出了有效的此类测定法 低至10拉德，这些将用于测试修复的饱和度， 测量DNA单链断裂、“双链”断裂和“双链”断裂的修复率 断裂”，以及作为辐射剂量函数的基底损伤。 探测 这三种类型的病变在引起细胞死亡或 转化，将试图抑制修复过程， 测试这种抑制对细胞存活或转化的结果。 此外，已显示影响细胞存活的程序将被 研究它们对修复的影响。 希望这些信息 从这些低剂量DNA损伤和修复的研究中获得的信息将是 用于（a）确定哺乳动物肩状存活曲线的原因 和（B）确定引起细胞死亡和转化的DNA损伤 这样，随着细胞修复能力的知识，低的危害， 辐射剂量可以外推。

Repair of ionizing radiation induced damage in mammalian cell DNA is crucial to cell survival. Shoulders on mammalian cell radiation survival curves can be explained by invoking saturation of a repair process at higher doses. To probe this hypothesis, assays of damage are required which can be used at low radiation doses (within the shoulder) as well as high radiation doses. Such assays are proposed here which are effective down to 10 rads, these will be used to test for saturation of repair, measuring rates of repair of DNA single strand breaks, "double strand breaks", and base damage as a function of radiation dose. To probe the significance of these three types of lesions in causing cell death or transformation, attempts will be made to inhibit the repair process and test the result of this inhibition on cell survival or transformation. Also procedures which have been shown to affect cell survival will be probed as to their effects on repair. It is hoped that the information gained from these studies of DNA damage and repair at low doses will be useful in (a) determining the cause of mammalian shouldered survival curves and (b) determining the DNA lesions causing cell death and transformation so that, with the knowledge of cell repair capacity, the hazards of low dose radiation can be extrapolated.