Inhalation Carcinogenicity and ChronicToxicity of Indium-tin Oxide in Rats and Mice: Kasuke NagaNo, et al. Japan Bioassay Research Center, Japan Industrial Safety and Health Association-Objectives: Carcinogenicity and chronic toxicity of indium-tin oxide (ITO) were examined by inhalation exposure of rats and mice to ITO aerosol. Methods: Fifty mice of both sexes were exposed to ITO at 0 (control), 0.01, 0.03 or 0.1 mg/m 3 for 6 h/day, 5 day/wk for 104 wk, and 50 rats of both sexes were exposed to 0, 0.01 or 0.03 mg/m 3 ITO for the same time period. The repeated exposure of 50 rats of both sexes to 0.1 mg/m 3 ITO was discontinued at the 26th wk, followed by clean air exposure for the remaining 78 wk. Results: In rats, incidences of bronchiolo-alveolar adenomas and carcinomas, bronchiolo-alveolar hyperplasia, alveolar wall fibrosis and thickened pleural wall, alveolar proteinosis and infiltrations of alveolar macrophages and inflammatory cells were significantly increased. Combined incidences of malignant lung tumors in male rats and total lung tumors in male and female rats were significantly increased at exposure to 0.01 mg/m 3 ITO. In mice, no carcinogenic response occurred, but thickened pleural wall, alveolar proteinosis and alveolar macrophage infiltration were induced. Mice were less susceptible to ITO than rats. The lung content of indium was the greatest, followed by the spleen, kidney and liver. Blood indium levels increased dosedependently. Conclusions: There was clear evidence of carcinogenicity of inhaled ITO in male and female rats but not clear evidence in mice, together with occurrence of the chronic pulmonary lesions in both rats and mice. (J Occup Health 2011; 53: 175-187)

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DMF vapor absorptions via the skin and the lung were estimated to be 40.4 and 59.6%, respectively. Workers need to be aware of the risk of dermal absorption of DMF vapor as well as of the liquid. Though NMF concentrations adjusted by creatinine, specific gravity, and urinary volume showed good correlation with total NMF excretion and the absolute amount of NMF at each sampling time, creatinine-adjusted NMF concentration correlated better than the others. The biological half-life of urinary NMF after dermal exposure, 4.75 +/- 1.63 h, was longer than that after respiratory exposure, 2.42 +/- 0.63 h.

Objective-A prospective cohort study was designed to clarify the relations between occupational exposure to carbon disulphide (CS 2 ) and its eVects on arteriosclerosis in workers in 11 Japanese rayon manufacturing factories. This report is a cross sectional baseline observation in the first study year. Methods-Study subjects were 432 male rayon workers (mean (range) age 35.5 (19.1-47.8); duration of exposure 13.4 (0.3-29.0)) and 402 male referent workers (age 35.8 (18.9-49.8)). Exposure to CS 2 was assessed by determining the concentration of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Mean (SD) TTCA was 3.42 (2.73) mg/g creatinine (Cr) (n=422). About a quarter of the urine samples were >5 mg/g Cr, a biological exposure index recommended by the American Conference of Governmental Industrial Hygienists. Health eVects on arteriosclerosis were evaluated by measuring blood pressure, serum lipids, pulse wave velocity of the aorta, stiVness and blood flow of the carotid artery, and blood coagulation and fibrinolysis indices, and by use of brain magnetic resonance imaging, electrocardiogram (at rest and after exercise), ophthalmograph, and Rose's questionnaire. Information on potential confounding factors was collected by self administered questionnaire. Results-Prevalence of microaneurysm of the retinal artery was significantly higher in workers exposed to CS 2 (8.1%) than in referent workers (3.4%), and increased with age. Other examinations did not show any diVerences between the two groups even after allowance for confounding factors. Conclusions-Significant eVects of CS 2 on arteriosclerosis were not found in current rayon manufacturing workers, with the exception of induction of microaneurysm of the retinal artery.