Journal of Environmental Pathology, Toxicology and Oncology

ISSN for PRINT: 0731-8898

For Online Access

Best Paper Award Selection - Editorial Board Site

2006, Volume25

Issue 3

82 pages

Issue price - $172.00

Michiharu Matsumoto
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Shigetoshi Aiso
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Hideki Senoh
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Kazunori Yamazaki
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Heihachiro Arito
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Kasuke Nagano
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Seigo Yamamoto
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Taijiro Matsushima, Ph.D.
Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hirasawa, Hadano, Kanagawa, Japan

Carcinogenicity and chronic toxicity of para-chloronitrobenzene (p-CNB) were examined by feeding diets containing p-CNB to rats and mice of both sexes for two years. The dietary concentration of p-CNB was 0 (control), 40, 200, or 1000 ppm (w/w) for rats and 0, 125, 500, or 2000 ppm for mice. Survival rates of the high-dosed male rats and male mice were significantly decreased compared with those of the respective controls, and this was attributed to the increased number of cancer deaths. Therefore, the high-dose levels were considered not to exceed the maximum tolerated dose. Significant decreases in red blood cell counts and hematocrit value and an increase in mean corpuscular volume were noted in the p-CNB-fed rats and mice. Nonneoplastic splenic lesions were characterized by capsule hyperplasia, fibrosis, fatty metamorphosis, and increased extramedullary hematopoiesis in rats, and congestion, increased extramedullary hematopoiesis, hemosiderin deposition, and ossification in mice. Incidences of fibromas, fibrosarcomas, osteosarcomas, sarcomas (NOS), and hemangiosarcomas in males and fibrosarcomas in females were significantly increased in the spleen of high-dosed rats. The most frequently observed splenic tumor was fibrosarcomas, followed by fibromas. The tumor incidences were increased in a dose-related manner and were more prevalent in males than in females. The malignant tumors metastasized mainly to the liver, peritoneum, and pancreas. Adrena/medullary hyperplasia and pheochromocytomas were significantly increased in the p-CNB-fed females. No tumor was induced in any of the p-CNB-fed mice of either sex except hepatic hemangiosarcomas in the 2000 ppm-fed females. Causative factors of p-CNB-induced carcinogenicity and chronic toxicity are discussed in light of the subchronic and chronic hematotoxicity reported in our present and previous studies and in the literature.

Download article, 571-584 pages

Article price - $35.00

<< Previous article   Next article >>