We performed a 90-day repeated-dose inhalation toxicity study of soluble hexavalent chromium trioxide (CrO3 (VI)). Male Sprague-Dawley (SD) rats were exposed to doses of CrO3 in the form of 0.5 approximately 5.0 microm aerosol at 0.00, 0.20, 0.50, and 1.25 mg/m3 for 6 h/day, 5 days/week for 13 weeks using inhalation chamber. CrO3 induced decrease of activity, alopecia and nasal hemorrhage. Body weights of the high-dose 1.25-mg/m3 exposure group were significantly lower than those of the control group. Hematological results revealed the reduction of the number of red blood cell and hematocrit values in the 1.25-mg/m3 exposure group. In addition, the hemoglobin values in the 0.50- and 1.25-mg/m3 exposure groups were significantly decreased compared with those of the control group. Clinical biochemical measurements revealed the reduction in total protein, albumin and alanine aminotransferase (ALT) level of the 0.50- and 1.25-mg/m3 exposure groups. Microscopic examination of the lung showed inflammation reactions caused by Cr exposure. In conclusion, the 13-week repeated exposure with soluble CrO3 demonstrated the injury in SD rats with the no observed adverse effect level (NOAEL) under 0.20 mg/m3.
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http://dx.doi.org/10.1007/s00204-004-0553-4 | DOI Listing |
J Toxicol Environ Health B Crit Rev
April 2005
CANTOX Health Sciences International, Mississauga, Ontario, Canada.
Styrene is a highly reactive monomer widely used in the plastics industry. The potential for styrene to produce genotoxic effects has been studied extensively in experimental systems. Styrene can induce sister chromatid exchanges (SCE) and chromosome aberrations (CA) in vitro under test conditions that enhance metabolism of styrene to styrene 7,8-oxide (SO)or reduce detoxification of 50 by epoxide hydrolase.
View Article and Find Full Text PDFInt J Occup Med Environ Health
March 2003
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Lódź, Poland.
Trimetylbenzene isomers: pseudocumene, hemimellitene and mesitylene, are major components of numerous commercial solvents and high-grade fuels. In our earlier research on rats we have proved that inhalation exposure to pseudocumene or hemimellitene at concentrations close to the MAC value results in behavioral changes detectable many weeks after cessation of the exposure. The aim of our present study is to determine whether exposure to mesitylene causes effects similar to those observed for pseudocumene and hemimellitene.
View Article and Find Full Text PDFInt J Occup Med Environ Health
March 1999
Department of Toxicity and Carcinogenesis, Nofer Institute of Occupational Medicine, Lódź, Poland.
Trimethylbenzene isomers (TMBs): 1,2,4-TMB (pseudocumene--PS), 1,2,3-TMB (hemimellitene--HM) and 1,3,5-TMB (mesitylene--MES) are important constituents of solvent mixtures. In the US, the adopted TLV-TWA value for TMBs is 125 mg/m3 or 25 ppm (ACGIH 1996). Recent experiments at our laboratory have revealed an impaired learning of passive and active avoidance responses and a longer persistence of an effect of footshock (increase in latency of the paw-lick response to heat) in rats tested several weeks after a four-week inhalation exposure (6h/day, five days/week) to PS at a concentration of 100 or 250 ppm (15).
View Article and Find Full Text PDFExperiments were conducted on 80 noninbred female rats. Inhalation exposures of the experimental animals to polysulfide of natural gas and condensate was daily made for 4 hours 5 times a week for 20 days. The mean concentration of chemical components was 2.
View Article and Find Full Text PDFFundam Appl Toxicol
January 1989
Monsanto Company, St. Louis, Missouri 63167.
Groups of 15 male and 35 female Sprague-Dawley rats were exposed to O,O'-dimethylphosphorodithioate (DMPDT) 6 hr/day, 5 days/week for 11 weeks. Initial target concentrations were 0, 4, 25, and 200 mg/m3. However, because of excessive toxicity, the high-exposure level was reduced to 125 mg/m3 after 8 weeks.
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