Chromosome aberrations in individuals occupationally exposed to ethylene oxide, and in a large control population.

Chromosome aberration frequencies in 61 employees potentially exposed to ethylene oxide (ETO) were compared with those in unexposed control groups. We studied 3 worksites with differing historical ambient levels of ETO. Within worksites, groups were classified as high potential exposed, low potential exposed, or controls. Further control groups including an off-site community control group were added to give a total of 304 control individuals. Blood samples were drawn several times over a 24-month period. Aberrations were analyzed in 100 cells per sample after culture for 48-51 h. Worksites I, II and III respectively represented increasing levels of potential ETO exposure. At worksites I and II, no consistent differences in aberration frequencies were found among groups. At worksite III aberration frequencies in potentially exposed individuals were significantly increased compared with controls. The frequencies of cells with aberrations were 5.6% for the 2 individuals in the high potential exposure category and 2.6% for 23 persons in the low potential exposure group. The overall frequency of cells with aberrations in the matched control individuals was 1.4%. In the total control group of 304 individuals we found significant increases in aberrations associated with smoking and with increasing age. We have also reported previously an association between sister-chromatid exchange (SCE) frequency and ETO exposure (Stolley et al., 1984). When aberration frequencies were compared with levels of SCEs there was only a weak overall association. The correlation was found in potentially exposed but not in control groups, and for any individual, one observation could not be used to predict the other.

Prolymphocytic leukemia: flow microfluorometric, immunologic, and cytogenetic observations.

Cells isolated from four patients with prolymphocytic leukemia were evaluated by surface markers, cytogenetics, and flow microfluorometric analysis of cell size and DNA content. All four patients had B-cell markers with a high density of IgM, kappa type, and Ia-like antigen. Less intense staining for surface IgD was also observed. In each patient studied, chromosomal modes were in the hypodiploid or near-diploid range. Despite the karyotypic abnormalities, the cellular DNA content, as determined by flow microfluorometry, was within the normal limits in all cases. This suggests that the variability in chromosome numbers seen in these patients may reflect an abnormality in DNA package rather than differences in total DNA content. The modal electronic cell size of the prolymphocytes, determined by light scatter, was readily distinguishable from that of normal peripheral blood lymphocytes and the lymphocytes of chronic lymphocytic leukemia. Fewer than 4% of the peripheral prolymphocytes had S-phase DNA content, a finding consistent with the chronic nature of this leukemia.