Easy biodosimetry for high-dose radiation exposures using drug-induced, prematurely condensed chromosomes

Abstract

Purpose : To propose a practical method of biodosimetry for highdose estimation. Materials and methods : Okadaic acid in the range 100nm to 500nm was given for 1-6h to cultured lymphocytes that had been exposed in the range of 0Gy to 40Gy. The frequency of the cells with prematurely condensed chromosomes (PCC) was compared with that of metaphases accumulated by 0.05 mu g/ml colcemid. The dose-response relationship of the yield of prematurely condensed ring chromosomes (PCC rings) in the irradiated lymphocytes was examined. Results : The 0.05 mu g/ml colcemid collected few metaphases when lymphocytes were irradiated to over 10Gy. However, 500nm okadaic acid produced a substantial number of analysable PCC in lymphocytes that had been exposed in the range of 0Gy to 40Gy. After 1h of treatment, the 500nm okadaic acid gave the most suitable chromosome morphology for the analysis. PCC rings were narrow, which facilitated their detection in Giemsastained preparations. The yield of PCC rings increased dosedependently up to 20Gy. Conclusion : PCC rings are a more suitable indicator than dicentrics at high doses over 10Gy. This technique requires no particular equipment or exceptional skill. After a serious radiation accident, it can be easily performed in a short time in most medical facilities to obtain dose information to assist physicians.