Cornforth M N, Bedford J S
Science. 1985 Mar 29;227(4694):1589-91. doi: 10.1126/science.3975628.
The cells and tissues of patients with ataxia-telangiectasia (A-T), an inherited disease characterized by a high degree of proneness to cancer, are abnormally sensitive to ionizing radiation. Noncycling cultures of normal human and A-T fibroblasts were exposed to x-rays so that the breakage and rejoining of prematurely condensed chromosomes in the G1 phase could be compared. After a dose of 6.0 grays, both cell types had the same initial frequency of breaks and the same rate for rejoining of the breaks, but the fraction of breaks that did not rejoin was five to six times greater for the A-T cells. The results also show that progression of cells into the S phase is not a prerequisite for the increased frequency of chromosome fragments that appear in mitosis after A-T cells are irradiated in the G1 or G0 phase.
共济失调毛细血管扩张症（A-T）是一种遗传性疾病，其特征是极易患癌症，该疾病患者的细胞和组织对电离辐射异常敏感。将正常人及A-T成纤维细胞的非循环培养物暴露于X射线下，以便比较G1期过早凝聚染色体的断裂和重新连接情况。给予6.0戈瑞的剂量后，两种细胞类型具有相同的初始断裂频率和相同的断裂重新连接速率，但A-T细胞中未重新连接的断裂部分是正常细胞的五到六倍。结果还表明，细胞进入S期并非G1或G0期照射A-T细胞后有丝分裂中出现的染色体片段频率增加的先决条件。
