Selby C P, Tofilon P J, Deen D F
Department of Neurological Surgery, School of Medicine, University of California, San Francisco 94143-0520.
Radiat Res. 1988 Jul;115(1):187-91.
In 1984, Tofilon and Deen reported that X irradiation of 9L cells immediately after treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) produced greater than additive induction of sister chromatid exchanges (SCEs) compared to the sum of SCEs induced by each agent alone [Radiat. Res. 97, 171-177 (1984)]. We (C.P.S., D.F.D.) repeated experiments conducted by Tofilon and Deen, scored SCEs in a blind manner, and were unable to reproduce the original findings. Instead, we found that X rays and BCNU induced SCEs in an additive manner. The slides prepared in the original study are extant; they were coded and recounted blind. Data obtained in this reevaluation do not substantiate the previous report. We conclude that the original findings were apparently the result of bias introduced in the SCE scoring process. Our experience with the SCE assay emphasizes the need to recode SCE slide preparations and count SCEs blind.
1984年，托菲隆和迪恩报告称，在用1,3-双（2-氯乙基）-1-亚硝基脲（BCNU）处理9L细胞后立即进行X射线照射，与单独使用每种试剂诱导的姐妹染色单体交换（SCE）之和相比，产生了大于相加效应的SCE诱导[《辐射研究》97, 171 - 177（1984年）]。我们（C.P.S.，D.F.D.）重复了托菲隆和迪恩进行的实验，以盲法对SCE进行评分，但未能重现原始发现。相反，我们发现X射线和BCNU以相加方式诱导SCE。原始研究中制备的玻片现存；它们被编码并进行了盲法重新计数。此次重新评估获得的数据不能证实先前的报告。我们得出结论，原始发现显然是SCE评分过程中引入偏差的结果。我们在SCE检测方面的经验强调了对SCE玻片制备进行重新编码并以盲法计数SCE的必要性。
