Journal of toxicology and environmental health
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J Toxicol Environ Health · May 1980
Reaction of hemoglobin with nitric oxide and nitrogen dioxide in mice.
The reaction of hemoglobin with NO and NO2 was compared in mice exposed to these cases. Nitrosyl hemoglobin (NOHb) and methemoglobin (MetHb) were determined simultaneously by electron spin resonance spectrometry at -140 degrees C. In mice exposed to 40 ppm NO, NOHb became constant (0.7%) in 30 min and declined rapidly with a half-life of several minutes when the mice were removed to room air. ⋯ Dose-effect relationships were determined with both gases at concentrations ranging from 20 to 80 ppm. A linear relationship could be observed between the concentrations of the gases and NOHb, but NO produced more NOHb than did NO2. There was an exponential increase of MetHb, particularly at high concentrations of NO.
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An appraisal is made of these chemical carcinogens available in the human environment that have been implicated in the etiology of liver cancer. The possible role of mycotoxins is discussed in detail, in particular the association between the aflatoxins and liver cancer in Africa and the Far East.
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J Toxicol Environ Health · Sep 1978
Respiratory tract lesions in guinea pigs exposed to sulfuric acid mist.
Guinea pigs were exposed inhalation chambers to 25 mg/m3 sulfuric acid mist 6 h/d for 2 d, and the acute respiratory effects were correlated by light and electron microscopy. This concentration of acid was selected since lower concentrations result in only slight effects while higher concentrations result in death. By light microscopy, the most prominent pulmonary lesion at 48 h was segmental alveolar hemorrhage and edema accompanied by proliferation of alveolar macrophages and type 2 pneumocytes. The segmental distribution of the pulmonary lesion was reaffirmed by scanning electron microscopy, while transmission electron microscopy showed injury to the distal airways and changes in the vascular endothelium.
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J Toxicol Environ Health · Sep 1978
Effects in rats and guinea pigs of six-month exposures to sulfuric acid mist, ozone, and their combination.
Rats and guinea pigs were exposed to 0.5 ppm O3, 10 mg/m3 sulfuric acid (H2SO4) mist, or their combination for 6 h/d, 5 d/wk for 6 mo. Microscopic alterations were seen in the lungs of guinea pigs exposed to O3 alone or in combination with H2SO4 mist. No other microscopic lesions were present in either rats or guinea pigs. No biologically meaningful synergistic effects were noted in animals exposed to the combination of O3 and H2SO4 mist.
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J Toxicol Environ Health · Oct 1977
Effects in rats and guinea pigs of short-term exposures to sulfuric acid mist, ozone, and their combination.
Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. ⋯ The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3 sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone.