GENOTOXICOLOGICAL INVESTIGATION OF HOSPITAL NURSES OCCUPATIONALLY EXPOSED TO ETHYLENE-OXIDE .1. CHROMOSOME-ABERRATIONS, SISTER-CHROMATID EXCHANGES, CELL-CYCLE KINETICS, AND UV-INDUCED DNA-SYNTHESIS IN PERIPHERAL-BLOOD LYMPHOCYTES

Structural, and numeric chromosome aberrations (CA), sister-chromatid exchange (SCE), phytohemagglutinin stimulation (LI), proliferative rat e index (PRI), and UV light-induced unscheduled DNA-synthesis (UDS) we re investigated in peripheral blood lymphocytes (PBL) of 48 historical controls (''Controls''); of 14 hospital controls in Budapest, Hungary (''Budapest controls''); of 9 nurses occupationally exposed to low-do se ethylene-oxide (ETO) in Budapest (''Budapest exposed''); of 10 hosp ital controls in Eger, Hungary (''Eger controls''); and of 27 high dos e ETC-exposed nurses in Eger (''Eger exposed''), where neoplasias, mai nly breast cancers, were observed. ETO concentrations in the ambient a ir samples varied from 5 to 20 mg/m(3) in Budapest; and from 5 to 100 mg/m(3) in Eger. Both LI and PRI were depressed in Budapest exposed, i ndicating ETO-induced cytotoxicity and, however, normal in Eger expose d. SCE was slightly elevated in Budapest exposed, but significantly in creased in Eger exposed. The yields of cells with high frequency SCE ( HFC) were only increased in Eger exposed. The expected low CA frequenc ies were found in Controls and in Budapest controls. ETO exposures sig nificantly increased the CA frequencies in Budapest and Eger exposed. In Budopest exposed, as expected, we found deletions; in a lesser exte nt chromatid exchanges and dicentrics; but no rings were detected. The se results are in a good accordance to the published data of other inv estigations carried out on ETC-exposed human populations. However, in Eger exposed, beside the increased yields of deletions, the frequencie s of dicentrics and rings showed a significant excess compared to the reviewed data. An unexpected, significant increase of dicentric and ri ng frequencies was also detected among the hospital controls in Eger c ontrols without known clastogenic exposure. The role of confounding fa ctors (age, smoking and drinking habit, total leukocyte count and hema tocrit) was investigated by an analysis of variance on CA and SCE freq uencies in Controls and in Eger exposed. Leukocyte count and mean age showed only significant effects on CA in Eger exposed and on SCE in Co ntrols, respectively. A possible active confounding factor could be th e temporary natural radioactivity of the local tap water. UDS in Budap est exposed and in Eger control were significantly higher then in the Controls and in Budapest controls. In Eger exposed UDS was significant ly decreased compared to the Budapest exposed and Eger control groups. The explanation of the present results is difficult on the basis of t he reviewed data on ETC-induced CA frequencies in exposed human popula tions, and it raises an issue of an independent genotoxic effect in Eg er, which is common both in Eger controls and in Eger exposed, such as natural radioactivity. (C) 1996 Wiley-Liss, Inc.