Environment: Peculiar Pigment Cell Neoplasm in Fish

Chromatophoroma in the croaker (Nibea mitsukurii) showed a unique geographic distribution. The contribution of environmental chemicals to the cause of chromatophoroma in the feral croaker is considered likely on the basis of the following results in our studies. 1) Chromatophoroma was induced in tank-reared N. mitsukurii by administration of certain kinds of known carcinogens such as 7,12-dimethyl-benz(a)anthra-cene, N-methyl-N'-nitro-N-nitrosoguanidine, and nifurpirinol. 2) Local accumulation of pigment-cell hyperplasia in the catfish (Protosus anguillaris) showed similar tendencies to those of chromatophoroma in N. mitsukurii. 3) Removal of contaminated sediment from the harbor and the river appeared to reduce the incidence from 47% in 1973–1983 to about 20% in 1985–1987. 4) Waste water from a factory located at the station where the incidence of the neoplasm was the highest contained mutagenic substances such as chloroacetones and glyoxals [5]. Exposure of catfish to the waste water induced pigment-cell hyperplasia on the skin. J Invest Dermatol 92:248S–254S, 198

Genotoxicity of nano/microparticles in in vitro micronuclei, in vivo comet and mutation assay systems

<p>Abstract</p> <p>Background</p> <p>Recently, manufactured nano/microparticles such as fullerenes (C₆₀), carbon black (CB) and ceramic fiber are being widely used because of their desirable properties in industrial, medical and cosmetic fields. However, there are few data on these particles in mammalian mutagenesis and carcinogenesis. To examine genotoxic effects by C₆₀, CB and kaolin, an <it>in vitro </it>micronuclei (MN) test was conducted with human lung cancer cell line, A549 cells. In addition, DNA damage and mutations were analyzed by <it>in vivo </it>assay systems using male C57BL/6J or <it>gpt </it>delta transgenic mice which were intratracheally instilled with single or multiple doses of 0.2 mg per animal of particles.</p> <p>Results</p> <p>In <it>in vitro </it>genotoxic analysis, increased MN frequencies were observed in A549 cells treated with C₆₀, CB and kaolin in a dose-dependent manner. These three nano/microparticles also induced DNA damage in the lungs of C57BL/6J mice measured by comet assay. Moreover, single or multiple instillations of C₆₀and kaolin, increased either or both of <it>gpt </it>and Spi^-mutant frequencies in the lungs of <it>gpt </it>delta transgenic mice. Mutation spectra analysis showed transversions were predominant, and more than 60% of the base substitutions occurred at G:C base pairs in the <it>gpt </it>genes. The G:C to C:G transversion was commonly increased by these particle instillations.</p> <p>Conclusion</p> <p>Manufactured nano/microparticles, CB, C₆₀and kaolin, were shown to be genotoxic in <it>in vitro </it>and <it>in vivo </it>assay systems.</p