Abstract:

OBJECTIVE: To investigate the value of prematurely drug induced condensed chromosomes ring (PCC-R) assay in estimating the biological doses in the victims of radiation accident. METHODS：Samples of peripheral blood were collected from the five victims (subjects 1-5) of the radiation accident of Taiyuan，Shanxi，16 hours after the accident. Bone marrow samples were collected 23 h after and peripheral blood sample 24 h after the accident from subject 1. The frequencies of PCC-R in PCC cells obtained by Okadaic acid (OA) induction were counted. A biological dose estimation was performed by a dose-effect curve of PCC-R (1-20 Gy). The frequencies of the PCC-R for the 4 victims (subjects 2-5) were analyzed 31 days after the accident. The results from PCC-R assay were verified by dicentrics plus centric rings (dic+r)，Cytokinesis-block micronuclei (CBMN) assay and physical method. RESULTS：No or rare PCC cells were observed in the peripheral blood cultures from subject 1. However，PCC cells were obtained from bone marrow cultures in subject 1 and in peripheral blood cultures from subject 2-5. The doses estimated for subject 1-5 were 12.4，3.6，3.2，1.7 and 1.5 Gy，respectively. A decrease of PCC-R frequencies were observed 31 days after the accident，and the extent of the decrease were 51%，69%，69% and 44% for the subjects 2-5，respectively，compared with the data 16 h after the accident. The estimated doses were in accordance with those doses estimated by dic+r，CBMN assay，physical method and clinical symptoms. CONCLUSION：Drug induced PCC-R assay is convenient and rapid，and the new curve of PCC-R is accurate and reliable. It is especially suitable for estimating higher dose of irradiation. However，blood samples should be collected as soon as possible and should be done within one month after the accident.

Key words: radiation accident, prematurely condensed chromos romesing, biodosimetry