Risk of cancer in an occupationally exposed cohort with increased level of chromosomal aberrations.

We used cytogenetic analysis to carry out a cohort study in which the major objective was to test the association between frequency of chromosomal aberrations and subsequent risk of cancer. In spite of the extensive use of the cytogenetic analysis of human peripheral blood lymphocytes in biomonitoring of exposure to various mutagens and carcinogens on an ecologic level, the long-term effects of an increased frequency of chromosomal aberrations in individuals are still uncertain. Few epidemiologic studies have addressed this issue, and a moderate risk of cancer in individuals with an elevated frequency of chromosomal aberrations has been observed.

Study of the genotoxicity of toluene.

Chromosome analysis was conducted for peripheral lymphocytes of 23 printers exposed to toluene concentrations of 590 mg/m3 in a rotary machine workshop and to rotogravure printing inks. The percentages of aberrant cells were 2.30 in the printers and 1.

Immunofluorescence studies on amphibian myoblast differentiation.

Differentiating myoblasts from urodele amphibians were cultivated in vitro and treated by immunofluorescence techniques and (or) inhibitors of RNA and protein syntheses. These experiments lead to the conclusion that the differentiation of these cells is directed by long-lived m-RNAs which are already present in morphologically undifferentiated cells and may act for at least 6 days. Contrary to observations on cultivated myogenic cells from other groups, the fusion of urodele myoblasts is not a prerequisite for a normal and functional differentiation (contractions) since isolated myoblasts differentiate quite normally.