Chromosomal aberrations in peripheral lymphocytes from healthy subjects asdetected in first cell division

Baseline frequencies of chromosomal aberrations were analysed in human peri pheral lymphocytes and the influence of age, sex and smoking habits was con sidered. From 53 healthy subjects (29 males, 24 females) 54,689 exclusively first division cells (M1) were scored. The frequencies of chromosome aberr ations per 1800 cells were 1.15 +/- 0.15 dicentrics (dic), 2.6 +/- 0.3 exce ss acentric fragments lace) and 7.0 +/- 0.6 chromatid breaks (crb). An age dependency could only be established for ace. Between males and females no differences in any of the aberration types were observed. For heavy smokers (> 30 cigarettes per day) a significant increase was only found for dic (2 .5 +/- 0.6 per 1000 cells). Dicentric frequency was compared with backgroun d levels of other studies in which results were reported also from exclusiv ely M1 cells. Despite cell cycle control, differences between laboratories can be observed which may be partly influenced by environmental conditions. But on the other hand the mean frequency of dic (excluding heavy smokers) of 0.95 per 1000 cells reported here is consistent for more than one decade . Since such a consistency of the mean frequency of dic is reported also fr om another laboratory, the conclusion is drawn that especially for the dete ction of low-level exposures, each laboratory should establish its own base line data, otherwise, the interpretation of the findings is dependent on t he selected background level from the literature. (C) 1999 Elsevier Science B.V. All rights reserved.