INCREASED FREQUENCY OF SISTER CHROMATID EXCHANGE IN WORKERS EXPOSED TO HIGH-DOSES OF METHYLMETHACRYLATE

Methylmethacrylate (MMA) is a volatile liquid widely used in the manufacture of acrylic polymers. Apart from its general toxicity (cardiac, respiratory, cutaneous, etc.), MMA is a potential mutagenic agent. Data on the mutagenicity of MMA is available almost exclusively with in vitro systems, thus the demonstration of genetic effects produced by monomeric MMA vapours in exposed workers is valuable additional information. An in vivo sister chromatid exchange (SCE) test was performed using lymphocytes from 31 workers occupationally exposed to MMA and a control group of 31 men whose mean age and smoking habits were similar. Our results indicate that the number of SCE in exposed workers (7.85 +/- 2.66) was not higher than the control group (7.49 +/- 2.33). However, the rate of SCE was significantly higher in the group exposed to MMA at peak concentrations ranging from 114 to 400 p.p.m. A few cells with a large number of SCE, called 'high frequency cells' (HFC), are responsible for this increase.