Makrigiorgos G M, Berman R M, Baranowska-Kortylewicz J, Bump E, Humm J L, Adelstein S J, Kassis A I
Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115.
Radiat Res. 1992 Mar;129(3):309-14.
The neutral elution technique (pH 9.6) has been used to compare the damage produced in the DNA of V79 cells following the decay of the Auger-electron emitters 123I and 125I incorporated into DNA in the form of 5-[123I/125I]iodo-2'-deoxyuridine (123IdU, 125IdU) or after 60Co gamma irradiation. Elution profiles of retained radioactivity versus eluted volume were generally found to be nonlinear and partially dependent on the cell treatment prior to elution. Plots of a suitable function of radioactivity retention on the filters versus total decays for 123I or 125I and dose (Gy) for gamma radiation were linear. Assuming that each 125I decay produces one double-strand break (DSB), the 60Co efficiency in DSB production was found to be 53.4 DSBs/Gy/cell (or 17.8 DSBs/Gy/10(12) Da), in agreement with values reported previously. The decay of 123I led to 0.74 DSB/decay/cell if decays occurring only during nonrepair conditions were counted. This DSB production efficiency is in agreement with Monte Carlo semiempirical models of the action of radiation on DNA.
采用中性洗脱技术（pH 9.6）比较了V79细胞DNA在掺入5-[123I/125I]碘-2'-脱氧尿苷（123IdU、125IdU）形式的俄歇电子发射体123I和125I衰变后或经60Coγ射线照射后所产生的损伤。保留放射性与洗脱体积的洗脱曲线通常呈非线性，且部分取决于洗脱前的细胞处理。滤膜上放射性保留的合适函数与123I或125I的总衰变数以及γ射线剂量（Gy）的关系图呈线性。假设每次125I衰变产生一个双链断裂（DSB），发现60Co产生DSB的效率为53.4 DSBs/Gy/细胞（或17.8 DSBs/Gy/10(12) Da），与先前报道的值一致。如果仅计算在非修复条件下发生的衰变，123I的衰变导致0.74 DSB/衰变/细胞。这种DSB产生效率与辐射对DNA作用的蒙特卡罗半经验模型一致。
