Biomedical Engineering Reference
In-Depth Information
(hyperplasia of reactive astroglias in the white matter) of questionable
significance (reversible during recovery?) were also seen at the final
sacrifice in all treatment groups (2.5 years). The nervous system effects
were judged to be transient and reversible after exposure was terminated.
Slight changes in liver and kidney were noted in monkeys exposed to
1000 ppm and kidney effects were reported at 100 ppm in the final
sacrifice. ECG indicated slight myocardial effects and degeneration of
the thalamus at 100 ppm and higher.
No changes in feed consumption, water consumption, body temper-
ature, hematology, the cerebral cortex, and the peripheral nerves or in
the retina, were noted. The NOAEL was
<
10 ppm and the LOAEL was
10 ppm based on the reported slight pathological changes in the nervous
system.
The doses in this study were the basic for the doses used in the NEDO
chronic and carcinogenicity studies in mice and rats.
Andrews et al. (1987) reported on a subchronic inhalation study of
methanol in rats and monkeys. The targeted exposure concentrations
were 0, 500, 2000, or 5000 ppm for 5 days per week, 6 hours per day for
4 weeks. Five male and five females Sprague Dawley rats and three
male and three females M. cynomolgus monkeys were exposed at each
test level. The methanol used was 99.85% pure. Body weights were
measured weekly, and clinical observations were made twice daily. In
addition, ophthalmic examinations were made pretest and at termina-
tion of the study. At termination organ weights were taken (adrenal
gland, heart kidney, liver, lung spleen, testes, and ovaries). Approxi-
mately 35 tissues were examined microscopically.
The chamber mean measured concentrations were 550, 1980, and
5010 ppm. In rats, lacrimation and nasal discharge were observed in the
treated animals, but only mucoid discharges were dose related. No
treatment related clinical signs were noted in the monkey. No treatment
related effects were noted in organ weight or body weights in any
treated group of rats or monkeys. No ocular abnormalities were noted at
the termination of the study. Gross and histological examination at
termination of the study revealed no treatment related effects. No ocular
abnormalities were noted in any of the high dose monkeys or rats when
compared to controls.
