Departments of Molecular Biosciences, Radiation Effects Research Foundation, Hiroshima, Japan.
Int J Radiat Biol. 2024;100(8):1155-1164. doi: 10.1080/09553002.2024.2373750. Epub 2024 Jul 11.
For Hiroshima and Nagasaki survivors, it has not been possible to calculate individual doses from the cytogenetic data and compare them with the physically estimated doses. This is because the cytogenetic studies used solid Giemsa staining which only provides the percent of cells bearing at least one stable-type aberration (most of the unstable-type aberrations had already disappeared), and a gamma-ray dose plus a 10-times neutron dose was used to integrate the data for both cities.
To compare the FISH-derived gamma-ray dose with the DS02R1-derived gamma-ray dose after correcting for a contribution of the neutron dose. It was also an attempt to determine if the frequency of stable-type aberrations had remained unchanged after the exposure.
Stable exchange-type aberration data was obtained using the 2-color FISH method from 1,868 atomic bomb survivors in Hiroshima and Nagasaki. The collected frequency was first extended to a genome-equivalent frequency. Then, by using known induction rates of exchange-type aberrations in vitro caused by neutrons and gamma-rays, respectively, and the mean relationship between the neutron and gamma-ray doses in the DS02R1 estimates for the survivors, the gamma-ray effect was estimated from the total yield of translocations.
It was found that over 95% of individual cytogenetic gamma-ray doses fell within the expected range of plus/minus about 1 Gy from the DS02R1 dose and the mean slope for the linear regression was 0.98, which reassures us of the validity of the DS02R1 study.
The present results demonstrate the validity of the individual DS02R1 doses, and that the frequency of stable-type aberrations in blood lymphocytes did not decay over the years, and thus is useful for retrospective dose evaluations of exposures which took place in the distant past.
对于广岛和长崎的幸存者来说，由于无法从细胞遗传学数据中计算出个体剂量并将其与物理估计剂量进行比较，因此一直无法做到这一点。这是因为细胞遗传学研究使用了固体吉姆萨染色，该染色仅提供至少带有一种稳定型畸变的细胞的百分比（大多数不稳定型畸变已经消失），并且使用γ射线剂量加 10 倍的中子剂量来整合两个城市的数据。
比较 FISH 衍生的γ射线剂量与 DS02R1 衍生的γ射线剂量，同时校正中子剂量的贡献。这也是尝试确定暴露后稳定型畸变的频率是否保持不变。
从广岛和长崎的 1868 名原子弹幸存者中使用双色 FISH 方法获得稳定易位型畸变数据。首先将收集到的频率扩展到基因组等效频率。然后，分别使用已知的体外中子和γ射线引起的易位型畸变的诱导率，以及幸存者的 DS02R1 估计中的中子和γ射线剂量之间的平均关系，从总易位产额估算γ射线的效应。
发现超过 95%的个体细胞遗传学γ射线剂量落在 DS02R1 剂量的正负 1Gy 左右的预期范围内，线性回归的平均斜率为 0.98，这使我们对 DS02R1 研究的有效性充满信心。
目前的结果证明了个体 DS02R1 剂量的有效性，并且血液淋巴细胞中的稳定型畸变频率多年来没有衰减，因此对于回溯评估遥远过去的暴露剂量是有用的。
