Molecular and cytogenetic studies on hematopoietic cells in heavily exposed A-bomb survivors

1 .目前无临床症状的重度暴露原子弹幸存者的研究；a)细胞遗传学研究显示外周淋巴细胞有5 ~ 45.6%的染色体异常。据估计轰炸时的辐射量为9- 650 rad。b)抗bast抗体的血清学研究表明，近端暴露组的位置病例百分比明显更高。c)分子生物学研究显示，分别在2名和1名幸存者中发现了转化-N-ras和K-ras基因。有原子弹辐照史的白血病患者的研究。a)急性白血病的细胞遗传学研究：对广岛75例与辐射有关的白血病（急性非淋巴细胞）进行了细胞遗传学检查，其中包括16例暴露于一种以上Gray的患者。根据DS86估计骨髓剂量对幸存者染色体畸变频率的数据进行统计分析，发现重度暴露患者的染色体畸变率明显高于非暴露患者。此外，观察到幸存者的染色体畸变具有更复杂的性质，并具有继发性白血病的特征。b)对暴露组和非暴露组进行了急性和慢性白血病转化基因和慢性髓细胞白血病bcr基因的分子生物学研究。到目前为止，在N-点突变的频率和位点上没有观察到明显的差异。和K-ras基因或bcr基因重排，最终得出辐射诱导白血病特异性的结论。

I. Studies on heavily exposed A-bomb survivors who have no clinical trouble at present ;a)Cytogenetic studies revealed 5- 45.6% of chromosome abnormalities in the peripheral lymphocytes, which were. estimated to be 9- 650 rad of exposure at the time of bombing.b)Serological studies for anti-BAST antibody shown that percent of position cases was significantly higher in the proximally exposed group.c)Molecular-biological studies revealed the transforming -N-ras and K-ras genes in two and one survivors, respectively.II. Studies on leukemia patients with a history of exposed to Atomic Bomb Radiation.a)Cytogenetic study on acute leukemia :Seventy five radiation--'related leukemia(acute non-lymphocyte)in Hiroshima including 16 patients exposed to more than one Gray were cytogenetically examined. Statistical analysis of the data on the frequencies of chromosomal aberrations in survivors according to the bone marrow doses of DS86 estimation revealed that heavily exposed patients tended to have significantly higher aberration rates as compared, -with non-exposed patients. Furthermore, the chromosomal aberrations in the survivors were-observed to be of a more complex nature and had characteristic findings of secondary leukemia.b)Molecular biological studies on transforming genes in acute and chronic leukemia and the bcr gene in chronic myelocytic leukemia have been performed in exposed and non-exposed groups. So far, no distinctive differences have been observed in the frequency and the sites of point mutations in N-. and K-ras genes or in the rearrangement of the bcr gene, for a final conclusion of the specificity of radiation induced leukemia.