Biomedical Engineering Reference
In-Depth Information
histopathological lesions were seen in the liver in rats exposed at
2500mg/kg methanol. No treatment-related effects were seen in
body weights, food consumption, and clinical signs of toxicity, opthal-
mological evaluation, mortality, as well as gross and microscopic tissue
evaluation. The NOAEL was judged to be 500mg/kg (USEPA, 1986).
In limited earlier studies, only biochemical changes in the brain were
reported in five rats given 790mg/kg orally for 7 days (Saad, 1976).
In another study, no significant changes in physiological parameters
were noted in rats given 1%methanol in the drinking water for 6 months
(Lington and Bevan, 1994).
4.6.2 Non-Human Primates
In a study to develop information on the monkey as a model of
humans, six rhesus monkeys were given 2000 mg/kg bw methanol and
then followed with five doses of 500 mg/kg methanol within 1.5-6
days to prolong the state of intoxication. Acidosis, accumulation of
formic acid, and optic effects (little or no response to light and
pathological effects) were reported suggesting that the monkey was
a good model to study methanol poisoning in humans (Martin-Amat
et al., 1977).
4.6.3 Mice
In an oral life time study in mice (Apaja, 1980), three levels of
methanol in the drinking water were used as “special” control groups.
All groups had 30 mice per sex. This study was designed to assess
carcinogenicity of malonaldehyde in drinking water, but each of the
three test levels of malonaldehyde released a different amount of
methanol, which was used initially to stabilize malonaldehyde The
three “special” methanol control groups had levels of 0.22%, 0.444%,
or 0.898% methanol only in their drinking water. Therefore, this study
could give information on the potential effects of repeat oral exposure
of methanol in mice. No toxic effects due to methanol treatment were
reported in female mice. This study is discussed in more detail in
Chapter 8 on carcinogenicity.
