BALB/3T3小鼠胚胎成纤维细胞中掺入的放射性核素诱导的恶性转化。
Malignant transformation induced by incorporated radionuclides in BALB/3T3 mouse embryo fibroblasts.
作者信息
LeMotte P K, Adelstein S J, Little J B
出版信息
Proc Natl Acad Sci U S A. 1982 Dec;79(24):7763-7. doi: 10.1073/pnas.79.24.7763.
The induction of lethality and malignant transformation by 5-[125I]iododeoxyuridine and [3H]thymidine incorporated into cellular DNA and by x-irradiation was studied in vitro in BALB/3T3 cells. Under these conditions, 125I radiation is highly localized to small regions of the DNA at the site of each decay and produces DNA double-strand breaks with high efficiency. Incorporated 125I was found to be 12-16 times as lethal per decay as incorporated 3H. For the induction of malignant transformation, however, 125I was approximately 25 times as effective per decay as 3H. When the frequencies of transformation induced at various levels of survival by 125I, 3H, and x-rays were compared, lethality was found to correlate closely with transformation at doses that yielded significant cell killing. An exception occurred at low doses, where 125I appeared much more efficient than x-irradiation in inducing transformation; transformation frequencies equal to those induced by 3-5 Gy of x-rays resulted from 125I exposures that yielded little or no cell killing.
在体外对BALB/3T3细胞研究了掺入细胞DNA中的5-[¹²⁵I]碘脱氧尿苷和[³H]胸腺嘧啶核苷以及X射线诱导的致死性和恶性转化。在这些条件下，¹²⁵I辐射高度定位于每次衰变位点处DNA的小区域，并高效产生DNA双链断裂。发现掺入的¹²⁵I每次衰变的致死性是掺入的³H的12 - 16倍。然而，对于恶性转化的诱导，¹²⁵I每次衰变的有效性约为³H的25倍。当比较¹²⁵I、³H和X射线在不同存活水平诱导的转化频率时，发现在产生显著细胞杀伤的剂量下，致死性与转化密切相关。在低剂量时出现了一个例外，此时¹²⁵I在诱导转化方面似乎比X射线更有效；¹²⁵I照射产生的转化频率与3 - 5 Gy X射线诱导的频率相当，但几乎没有或没有细胞杀伤。
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