Edgren M, Révész L, Larsson A
Int J Radiat Biol Relat Stud Phys Chem Med. 1981 Oct;40(4):355-63. doi: 10.1080/09553008114551311.
Using the unwinding technique in weak alkali, the induction and repair of DNA single-strand breaks was determined after aerobic and anerobic X-irradiation of human fibroblasts, obtained from a patient suffering from 5-oxoprolinuria, and from a clinically healthy control. The metabolic disorder associated with 5-oxprolinuria is a deficiency in glutathione synthetase activity resulting in a greatly reduced glutathione content in the cells. A small dose-modifying effect of oxygen (o.e.r. = 1.1) was found for these cells in comparison to an o.e.r. of 2.5 for control cells with normal glutathione content. No significant difference was found between the repair capacity of cells with normal and deficient glutathione content, and repair was nearly completed within 60 min of anoxic irradiation in each case. In contrast, after aerobic irradiation of glutathione-deficient cells repaired less than 70 per cent of the breaks during the same period. When the glutathione-deficient cells were incubated with either dithiothreitol or mercaptopropionylglycine directly after aerobic irradiation, almost complete repair was obtained within 60 Min. The data are interpreted as indicating that the repair mechanism for oxically and anoxically induced single-strand breaks is qualitatively different, and requires glutathione in the former case.
运用弱碱解旋技术，对从一名患有5-氧脯氨酸尿症的患者以及一名临床健康对照者获取的人成纤维细胞进行需氧和厌氧X射线照射后，测定DNA单链断裂的诱导和修复情况。与5-氧脯氨酸尿症相关的代谢紊乱是谷胱甘肽合成酶活性缺乏，导致细胞内谷胱甘肽含量大幅降低。与谷胱甘肽含量正常的对照细胞的氧增强比（o.e.r.）为2.5相比，发现这些细胞的氧有较小的剂量修饰效应（o.e.r. = 1.1）。谷胱甘肽含量正常和缺乏的细胞的修复能力之间未发现显著差异，并且在每种情况下，缺氧照射后60分钟内修复几乎完成。相比之下，需氧照射后，谷胱甘肽缺乏的细胞在同一时期内修复的断裂少于70%。当谷胱甘肽缺乏的细胞在需氧照射后立即用二硫苏糖醇或巯基丙酰甘氨酸孵育时，60分钟内几乎可实现完全修复。这些数据被解释为表明需氧和厌氧诱导的单链断裂的修复机制在性质上不同，并且在前一种情况下需要谷胱甘肽。
