Blazek E R, Peak J G, Peak M J
Biological, Environmental, and Medical Research Division, Argonne National Laboratory, Illinois 60439-4833.
Radiat Res. 1989 Sep;119(3):466-77.
We have used nondenaturing filter elution performed at both pH 7.2 and pH 9.6 to measure the induction of double-strand breaks (DSBs) in the DNA of Chinese hamster V79 cells by 60Co gamma-radiation doses between 10 and 120 Gy. The absolute DSB yields as measured by this assay were determined by using our recent calibration of the assay based upon disintegrations of 125I incorporated into the DNA. An analysis of the dose-response relationship for the induction of DSBs by 60Co gamma rays showed that the number of DSBs induced per dalton of DNA was proportional to the square of the applied dose throughout the dose range used. The contribution made by the dose to the first power was small at pH 9.6 and negligible at pH 7.2. These results suggest that DSB induction in cells by gamma rays may be entirely a two-hit event.
我们使用在pH 7.2和pH 9.6条件下进行的非变性滤膜洗脱法，来测定60Coγ射线剂量在10至120 Gy之间时，对中国仓鼠V79细胞DNA双链断裂（DSB）的诱导情况。通过该检测方法测得的绝对DSB产率，是根据我们近期基于掺入DNA中的125I衰变对该检测方法进行的校准来确定的。对60Coγ射线诱导DSB的剂量反应关系分析表明，在所使用的整个剂量范围内，每道尔顿DNA诱导产生的DSB数量与所施加剂量的平方成正比。剂量的一次方贡献在pH 9.6时较小，在pH 7.2时可忽略不计。这些结果表明，γ射线对细胞中DSB的诱导可能完全是一个双打击事件。
