Biomedical Engineering Reference
In-Depth Information
nodes were seen in 2/52, 4/52, 5/52, and 10/52 at concentrations of 0,
10, 100, and 1000 ppmmethanol, respectively. At the top dose methanol
concentration (1000 ppm) the increase in nodes is statically significant.
Lung papillary adenomas in males were seen in 1/52, 5/50, 2/52, and
6/52 at concentrations of 0, 10, 100, and 1000 ppm methanol, respec-
tively. The increase in lung papillary adenomas was not significantly
different from the historical control rate.
The authors of the study concluded that “ methanol did not induce any
carcinogenic or toxic effects in rats at dose level of 1000 ppm or less.”
8.2.2.2 Mice
The design of the mouse inhalation study conducted by
NEDO (1986, 1987) was very similar in design to the inhalation rat study
just discussed. The major difference was the study ran for 18 months
instead of 2 years as in the rat study. Exposure was by inhalation for
19 hours per day, 7 days per week for 18 months with concentrations of
methanol of 0, 10, 100, or 1000 ppm. CRJ:B6C3F mice were used, 52
males and 53 females per group. OECD testing guidelines were used, and
again no indication that the studywas conducted under GLP. Clinical tests,
including checking for infection, body weight, feed consumption, and
organ weights were measured in addition to macroscopic and histological
evaluations of the standard tissues were evaluated. Survival was 93-100%
at termination (78 weeks). Blood methanol was not measured.
No treatment-related effects were observed in clinical tests, body
weight, feed consumption, organ weights, or histopathological exami-
nations. The lack of effect on body weight indicates that the top dose
may have been below a maximum tolerated dose (MTD). The authors of
the study concluded that “methanol did not induce any carcinogenic or
toxic effects in mice at dose level of 1000 ppm or less.”
8.2.3 Dermal
8.2.3.1 Mice
Methanol was used as a control/solvent in a topical
application study of photocarcinogenesis of retinoic acid. Retinoic acid
was dissolved in methanol for application to the back of 30 males and 30
females hairless mice (20 cm
2
) daily for 30 weeks. A control group
received 100 ul methanol only daily for 30 weeks. In a second group of
