Kanda R, Minamihisamatsu M, Hayata I
Radiation Hazards Research Group, National Institute of Radiological Sciences, Chiba, Japan.
Int J Radiat Biol. 2002 Sep;78(9):857-62. doi: 10.1080/09553000210152953.
To investigate the dynamics of chromosome aberrations in the blood cells of three workers severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan, in 1999.
The change with time of the frequency of' chromosome aberrations in the three patients was examined using a new analysis to score drug-induced prematurely condensed ring chromosomes (PCC-R) and a conventional meta-phase analysis.
The frequencies and cellular distributions of PCC-R, dicentrics and rings did not change significantly among the samples obtained at 9-48h after the accident while the first depletion of lymphocytes occurred. The distributions of these aberrations in the cells of two patients showed a slight overdispersion compared with a Poisson distribution reflecting neutron and non-uniform exposures. The dose response curve of rings paralleled that of dicentrics, but not PCC-R. The half-lives of PCC-R (8.5 months) and of rings (8.7 months) were shorter than that of dicentrics (13.5 months).
In the three patients of the Tokai-mura accident, lymphocytes in the circulating and extravascular pools had reached equilibrium at 9h, and highly damaged lymphocytes did not selectively move away from the circulatory system during the first rapid depletion of lymphocytes after exposure. Data on the in vivo half-life of PCC-R as well as dicentrics and rings obtained in the present study may be useful for retrospective dosimetry.
研究1999年发生在日本东海村临界事故中3名严重暴露于中子和γ射线的工人血细胞中染色体畸变的动态变化。
采用一种新的分析方法对药物诱导的早熟凝集环染色体（PCC-R）进行评分，并结合传统的中期分析，检测3例患者染色体畸变频率随时间的变化。
在事故发生后9 - 48小时采集样本时，淋巴细胞首次出现减少，此时PCC-R、双着丝粒染色体和环状染色体的频率及细胞分布无显著变化。与反映中子和非均匀照射的泊松分布相比，2例患者细胞中这些畸变的分布略有过度离散。环状染色体的剂量反应曲线与双着丝粒染色体平行，但与PCC-R不同。PCC-R（8.5个月）和环状染色体（8.7个月）的半衰期短于双着丝粒染色体（13.5个月）。
在东海村事故的3例患者中，循环池和血管外池中的淋巴细胞在9小时时达到平衡，暴露后淋巴细胞首次快速减少期间，高度受损的淋巴细胞并未选择性地从循环系统中移出。本研究获得的PCC-R以及双着丝粒染色体和环状染色体的体内半衰期数据可能有助于回顾性剂量测定。
