The oxidation of metallic mercury in vitro by red blood cells of normal, hypocatalasemia and acatalasemia human subjects is not always in proportion to catalase activity. Methemoglobin-hydrogen peroxide compounds and glutathione peroxidase in red blood cells appeared to accelerate mercury oxidation. The oxidation of metallic mercury in vivo in the lungs and blood of normal, hypocatalasemia and acatalasemia mice exposed to metallic mercury vapor was roughly proportional to the decrease in catalase activity. Six ferric compounds, catalase, cytochrome C, methemoglobin, lactoperoxidase, ferritin and ferric ion, had the ability to oxidize metallic mercury in the presence of hydrogen peroxide. The oxidation of metallic mercury by catalase extracts prepared from mushrooms, hay bacillus and spinach was also observed.
The hepatic mitochondrial and microsomal recovery of rats intoxicated with CCl4 was investigated with specific reference to the oxygen utilization of liver slices. In control rats, the major oxygen utilization of the liver slices was at-tributed to mitochondrial particles. Since the mitochondrial oxygen utilization was inhibited by cyanide, the microsomal oxygen utilization was induced by NADPH and phenobarbital (a substrate for microsomal mixed function oxidase). Changes in oxygen utilization were observed in the recovery course of rats intoxicated with CCl4, and the recovery of mitochondria was found to be faster than that of micro-somes. A sex difference was present in the recovery mechanism of the microsomes.
An attempt has been made to characterize the pathotoxicologic effects of 2, 5-Hexane diol (2, 5-Hxdl) on lymphoid organs in rats. Six week-old female albino rats were fed orally 2, 5-Hxdl at 0.0, 0.25, 0.5, 0.75 and 1.0 m//kg body weight dose levels for 7 days. There was a dose-related reduction in absolute and relative lymphoid organ weights. The magnitude of reduction in organ weights observed was in the following order : Thymus> Spleen>Lymph nodes. Histological examination of thymus revealed a preferential involution of the cortical region together with prominence of cortical epithelial cells. When allowed a rest period of 3 weeks after one week initial treatment of 2, 5-Hxdl, the recovery in lymphoid organ wt/body wt ratio was evident. Further in vitro experiments revealed a dose and time dependent cytotoxic effect to rat thymocytes. Significance of the findings has been discussed in the light of pathotoxicologic effects of 2, 5-Hxdl to lymphoid organs.
Inhalation exposure of guaranteed reagent grade trichloroethylene was performed in female ICR mice and female SD rats at 50, 150 and 450 ppm for 7 hours a day, 5 days a week, for 104 weeks followed by an observation period of 3 weeks. Tumors were distributed mainly in the hematopoietic systems, lungs and mammary glands in the mice, and in the pituitary glands and mammary glands in the rats, while several types of tumors were observed in other organs at low inci-dences. The average number of lung tumors per mouse in mice exposed to 150 ppm or 450 ppm was more than 3-fold the incidence in control mice. The incidences of pulmonary adenocarcinomas in mice exposed to 150 ppm and 450 ppm were 16% and 15%, respectively, which was significantly (p<0.05) higher than that of the controls (2%). No significant differences in the incidences of other types of tumors, tumors of specific organs by site of origin or numbers of animals with tumors were recognized between the controls and dosed groups of mice and rats.
By acute exposure of dogs to 1, 1, 1-trichloroethane and observing the changes in hematologic parameters during and after exposure, the following results were obtained. A marked but temporary decrease in leukocytes was noted 30 minutes after the start of exposure, but no change was observed in the erythrocytes, hematocrit values or thrombocytes. According to leukocyte differential counts, all types of leukocytes showed a decrease. The decrease in neutrophils was particularly pro-minent. A dose-response relationship was seen between the exposure concentrations of 1, 1, 1-trichloroethane from 200 to 700 ppm. and the grade of decrease in leuko-cyte counts.
Daily oral administration of carbon tetrachloride (0.5 ml/kg/day) for a period of 15 days, followed by endosulfan (2.0 and 4.0 mg/kg/d), carbaryl (50 and 100 mg/kg/d) and phosphamidon (0.5 and 1.0 mg/kg/d) for 15 days to different groups of male rats triggered significant enzymatic changes. Whereas treatment of CCl4 alone for a period of 15 days (group 5) elicited altered morphology of hepatocytes and a highly significant increase in the activity of serum transaminases, alkaline phosphatase, bilirubin content and severe hypoglycemia, CCl4-insecticide treatment did not suggest a synergistic efiect of the two groups of agro industrial chemicals in experimental animals. On the contrary, the values of enzymatic activity and blood sugar in CCl4-insecticide exposed animals were nearer to those of normal. A significant inhibition of acetylcholinesterase activity of brain and red blood cell was seen after phosphamidon alone (group 4) and after CCl4-phosphamidon treat-ments (groups 10 and 11) which also support lack of synergistic efiect of CCl4-phosphamidon.
The effect of maternally administered lead (Pb 5.0 mg/kg) and/or manganese (Mn 6 mg/kg) on the brain growth and some biochemicals was investi-gated in 21 day old pups exposed during gestation and/or lactation. The pups continuously exposed to the mixture of Pb and Mn during pre-and postnatal life presented with significant alterations in the body, brain weights, contents of DNA, RNA, protein and accumulation of both the metals in the brain, the magnitude of these changes was greater in pups exposed to the mixture of Pb and Mn during gestation+lactation than observed in pups identically exposed during gestation only. Pups subjected to any regime of metal exposure during lactation were least affected as indicated by no changes in the brain growth and biochemical parameters. Accumulation of Pb in the brain increased several folds in the animals exposed to the mixture of Pb and Mn in comparison to that observed after exposure to Pb alone. These data suggest that exposure to the two metal ions during prenatal and early postnatal life is more injurious to the brain growth than the identical exposure during the lactation alone.
A cross-sectional study on pulmonary functions and respiratory symptoms was undertaken in Japanese male workers in 18 viscose rayon plants to detect pulmonay effects associated with viscose exposure, especially to H2S. Measurement of the occupational exposure level (OEL) of H2S by personal passive diffusion dosimetry, and the forced expiratory flow-volume test before and after an eight-hour shift on the same workday was undertaken in 30 matched pairs of exposed and non-exposed workers. The OEL of H2S was 0.3 to 7.8 ppm, 3 ppm on the average, for the viscose exposed workers and less than 0.1 ppm for the referents. No significant difference in the eight-hour pulmonary function changes between the pairs was observed, and no significant correlation between the individual pulmo-nary function changes and individual OEL of H2S was obtained. Indices of the forced expiratory flow-volume test for 324 workers appeared to be better in ex-posed non-smokers than in non-exposed non-smokers. The prevalence rates of respiratory symptoms in 2379 exposed and 2968 referent workers using a modified self-administered BMRC questionnaire showed significant associations with smoking habits, but not with rayon work-history. No evidence of any appreciable effect of viscose exposure on pulmonary functions and symptoms was revealed in the Japanese rayon plant workers.