FISH examination of lymphocytes from Mayak workers for assessment of translocation induction rate under chronic radiation exposures

Burak LE, Kodama Y, Nakano M, Ohtaki K, Itoh M, Okladnikova ND, Vasilenko EK, Cologne JB, Nakamura N
Int J Radiat Biol 77(8):901-8, 2001

Summary

Purpose

To estimate the translocation-induction rate under chronic exposure conditions by measuring chromosome aberration frequencies in lymphocytes from Mayak nuclear workers using fluorescence in situ hybridization (FISH).

Materials and methods

Lymphocytes were examined from 27 nuclear workers at the Mayak Production Association and two control individuals using FISH with probes for chromosomes 1, 2 and 4. Official doses derived from worker film-badge records varied from 0 to 8.50 Gy.

Results

The mean (plus or minus SD) genome-equivalent translocation frequency (FG) was 2.30 (plus or minus 0.75)% in the zero-dose group (n = 7), and Poisson regression analysis provided the best-fit equation of FG(%) = 2.96(plus or minus 0.39) + 0.69(plus or minus 0.l4)D + 0.12(plus or minus 0.05)A, where D is the film-badge-derived dose (Gy), and A is age centred at 67 years. The induction rate would increase to nearly 1% Gy^-1 if the radiation dose to bone marrow, one of the major organs for lymphocytes and where their precursor cells reside, is considered.

Conclusion

The estimated induction rate in vivo appeared substantially smaller than linear coefficients estimated from various in vitro studies.