Handbook of Solvents - George Wypych - ChemTech - Ventech!

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proximately 4 days following the exposure. While looking at enzyme levels in the blood after
exposure to 1,1,1-trichloroethane, there was no evidence of elevated serum enzyme
levels. 80,82,83,84 Case studies of people exposed to a high concentration of
1,1,1-trichloroethane did not show elevated liver enzymes. 81,85 Histopathological examination
of the liver of patients who died following inhalation of a high concentration of
1,1,1-trichloroethane showed minimal changes, mainly those of mild fatty changes of the
liver. 86,87 Kramer et al. 88 studied humans at low levels of exposure and found minor changes
in liver enzymes. Experimental animal studies showed mild histopathological changes and
effects on liver enzymes. 89,90 Truffert et al. 91 showed that intermittent duration and intermittent
exposure to a low concentration of 1,1,1-trichloroethane produced a 67% increase in
the synthesis of DNA of the livers of exposed rats, and concluded that the DNA synthesis
measurements may be a more sensitive indicator of liver damage than just measurements of
liver enzymes. McNutt et al. 92 showed histological damage following exposure to
1,1,1-trichloroethane with hepatocyte necrosis. The most commonly reported effects of
1,1,1-trichloroethane on the liver in experimental animals is increased fat accumulation.
93,94,95 The function of duration of exposure played an important role in experimental
rats, and was seen in those who were exposed for 7 hours, but was not seen in those exposed
for 2 hours in high levels. Savolainen et al. 96 showed that exposure to a moderate concentration
in experimental animals caused decreased microsomal cytochrome P450 enzyme activity.
Overall, the animal studies and human studies suggest an effect of 1,1,1-trichloroethane
on the liver, but the severity appears to be related to the dose and duration of the exposure.
20.7.11 SUMMARY
In summary, from the available data, it is clear that exposure to solvents and hepatotoxicity
must be evaluated in context of the individual variability, exposure to mixture of solvents,
and synergistic toxicity.
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