Milligan J R, Aguilera J A, Wu C C, Ng J Y, Ward J F
Department of Radiology, University of California at San Diego, La Jolla, 92093-0610, USA.
Radiat Res. 1996 Apr;145(4):442-8.
Using agarose gel electrophoresis, we have measured the yields of DN A single- and double-strand breaks (SSBs and DSBs) for plasmid DNA irradiated in aerobic aqueous solution with either 137Cs gamma rays or 4He ions with a mean LET of 94 or 150 keV micron-1. The presence of dimethyl sulfoxide (DMSO) resulted in a decrease in the yields of both SSBs and DSBs, with a greater decrease being apparent for gamma irradiation than for 4He-ion irradiation. Irradiation by 4He ions in the presence of N-(2-thioethyl)- 1,3-diaminopropane (WR-1065) resulted in a decrease in the yield of SSBs and a slightly larger decrease in the yield of DSBs. Together with results obtained previously, these observations suggest a substantial contribution to the formation of SSBs and DSBs by 4He ions by species containing at least two radicals and more than two radicals, respectively.
我们使用琼脂糖凝胶电泳法，测量了在有氧水溶液中用平均传能线密度（LET）为94或150 keV/μm的¹³⁷Csγ射线或⁴He离子辐照质粒DNA时产生的单链和双链DNA断裂（SSB和DSB）的产额。二甲基亚砜（DMSO）的存在导致SSB和DSB的产额均降低，γ射线辐照时的降低幅度比⁴He离子辐照时更明显。在N-（2-硫代乙基）-1,3-二氨基丙烷（WR-1065）存在的情况下，用⁴He离子辐照导致SSB产额降低，DSB产额降低幅度稍大。与之前获得的结果一起，这些观察结果表明，至少含两个自由基和含两个以上自由基的物种分别对⁴He离子诱导形成SSB和DSB有很大贡献。
