(1990). Formaldehyde Toxicity—New Understanding. Critical Reviews in Toxicology: Vol. 20, No. 6, pp. 397-426.

Formaldehyde Toxicity—New Understanding

The implausibility of leukemia induction by formaldehyde: a critical review of the biological evidence on distant-site toxicity.

This paper reviews the ability of a number of chemicals to induce sister-chromatid exchanges (SCEs). The SCE data for animal cells in vivo and in vitro, and human cells in vitro are presented in 6 tables according to their relative effectiveness. A seventh table summarizes what is known about the effects of specific chemicals on SCEs for humans exposed in vivo. The data support the concept that SCEs provide a useful indication of exposure, although the mechanism and biological significance of SCE formation still remain to be elucidated.

ReviewSister-chromatid exchange: second report of the Gene-Tox program

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.

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

Sister-chromatid exchange (SCE) frequencies in employees potentially exposed to ethylene oxide (ETO) were compared with those in unexposed control groups. Three worksites where the previous environmental control of ETO was known to have differed were chosen. Within these worksites, subjects were categorized into high potential exposed, low potential exposed and control groups. An additional community control group was obtained. Blood samples for chromosomes studies of peripheral lymphocytes were dawn at several time points over a period of 24 months. The effects on SCE of age, sex, smoking habits and reader variation were considered. Worksites I, II and III, respectively, represented increasing levels of exposure. At Worksite III large differences among groups persisted over 24 months. At Worksite II, the SCEs in the high potential exposed workers were higher than those in the other groups. At no time was the low potential exposed group at Worksite II statistically significantly higher in mean SCE than the worksite controls. No consistent differences among groups were noted in Worksite I.

M.E. Phelps

Papers

Sister-chromatid exchange induction in peripheral blood lymphocytes of rats exposed to ethylene oxide by inhalation.