Dikomey E
Institute of Biophysics and Radiobiology, University of Hamburg, Federal Republic of Germany.
Int J Radiat Biol Relat Stud Phys Chem Med. 1988 Apr;53(4):667-78. doi: 10.1080/09553008814550991.
Survival as well as repair of DNA strand breaks were studied in CHO cells after exposure to internal beta-rays from incorporated [3H]thymidine at 4 degrees C (equivalent to an exposure at 'infinitely high' dose rate) and at 37 degrees C (low dose rate). DNA strand breaks were determined by the alkaline unwinding technique. In cells exposed at 4 degrees C cell killing was five times higher (Do = 250 decays per cell) than in cells exposed at 37 degrees C (Do = 1280 decays per cell). Strand breaks induced by 3H decay at 37 degrees C were repaired with the same kinetics as those generated at 4 degrees C. Therefore the different degrees of cell killing at 4 degrees C and 37 degrees C cannot be attributed to a difference in the repair kinetics for DNA strand breaks.
在4℃（相当于“无限高”剂量率照射）和37℃（低剂量率）下，对暴露于掺入的[3H]胸腺嘧啶产生的内源性β射线后的中国仓鼠卵巢（CHO）细胞的存活情况以及DNA链断裂的修复情况进行了研究。通过碱性解旋技术测定DNA链断裂。在4℃照射的细胞中，细胞杀伤率比在37℃照射的细胞高5倍（Do = 每个细胞250次衰变）（Do = 每个细胞1280次衰变）。37℃下3H衰变诱导的链断裂与4℃下产生的链断裂以相同的动力学进行修复。因此，4℃和37℃下不同程度的细胞杀伤不能归因于DNA链断裂修复动力学的差异。
