Increasedhprt mutant frequencies in Brazilian children accidentally exposed to ionizing radiation

Dose-Rate Effect on the Induction ofHPRTMutants in Human G0Lymphocytes ExposedIn Vitroto Gamma Radiation

“…In recent times, estimating the somatic mutant frequency at the HPRT locus using a clonogenic assay has gained importance as a biomarker of radiation exposure and radiation effect as seen from studies of radiotherapy technicians (9), cancer patients undergoing radiation therapy (10), Brazilian children accidentally exposed to ionizing radiation (11), and Chernobyl cleanup workers with semi-acute lowdose radiation exposures (12).…”

hprt mutant frequencies, nonpulmonary malignancies, and domestic radon exposure: ?Postmortem? analysis of an interesting hypothesis

“…Based on previous studies of persons exposed to low-LET radiation, it appears that elevations in hprt mutant frequencies can be reliably detected at total body doses above 1 Sv [Messing and Bradley, 1985;Nicklas et al, 1990Nicklas et al, , 1991Sala-Trepat et al, 1990;Albertini et al, 1992;da Cruz et al, 1996Saddi et al, 1996;Thomas et al, 1999]. For doses lower than 1 Sv but higher than 10 mSV, the dose-response data are inconsistent Hakoda et al, 1998a], and for doses lower than 10 mSv, the assay is unreliable as a biomarker for dose [Cole and Skopek, 1994].…”

“…There is similar evidence from persons exposed in radiation accidents in Gioania, Brazil [da Cruz et al, 1996, 1997Saddi et al, 1996; and Chernobyl [Moore et al, 1997;Thomas et al, 1999]. In contrast to the in vitro studies, many of the epidemiologic studies showed only weak increases in hprt mutation frequency with dose, and none showed strong dose-response relations.…”

“…Specifically, dose-response relations have not been detected in uranium miners exposed to radon and its progeny [Shanahan et al, 1996], in radiation workers [Seifert et al, 1993], and in flight engineers [Zwingmann et al, 1998]. The discrepancies between results from laboratory and epidemiologic studies suggest that hprt mutant frequency is not a reliable biomarker for exposures that result in doses below 1 Gy [da Cruz et al, 1996Saddi et al, 1996], and that the results from this assay must be interpreted with caution.…”