Biomedical Engineering Reference
In-Depth Information
methanol/gasoline, gasoline, 5 days per week 6 hours per day for
4 weeks (Poon et al., 1994, 1995). In the first study, methanol exposure
was 300 or 3000 ppm. Mild to moderate changes in the thyroid were
noted in all treated groups (methanol, toluene, and methanol/ toluene).
Changes in the nasal cavity were also noted in high dose methanol
group (Poon et al., 1994). In the second study, only the methanol level
was changed (2500 ppm). The treatment-related effects were mild
changes in the nasal cavity, hepatmegaly, and liver enzyme changes
attributed primary to the gasoline in the gasoline only or combination of
methanol/gasoline (Poon et al., 1995).
4.5.3 Mice
The design of the mouse chronic inhalation study conducted by NEDO
was very similar to the chronic rat study just discussed (NEDO, 1986,
1987). Exposure was by inhalation for 20 hours per day for 12 months
with concentrations of methanol of 0, 10, 100, or 1000 ppm. CRJ:
B6C3F mice were used, 30 males and 30 females per group. This study
was run at the same time as an 18-month carcinogenicity in mice, which
is discussed in more detail in Chapter 8 on cancer. OECD testing
guidelines were used, and again no indication that the study was
conducted under GLP was mentioned. Ten mice per group were
sacrificed at 6 months and the remaining 20 per group were scarified
at 12 months. Clinical tests, plus checking for infection, body weight,
feed consumption, and organ weights were evaluated. In addition,
macroscopic and histological evaluations of the standard tissues
were conducted. No treatment-related effects were observed in clinical
tests, organ weights, or in histopathological examinations at 100 ppm or
lower. Food consumption varied based on dose, time in the study, and
body weight change. However, no clear treatment-related trend was
observed. Slight changes that may be treatment related (weight gain,
organ weight, and fatty liver degeneration) were observed in male mice
exposed at 1000 ppm methanol. One mouse died during the study and
one was sacrificed (100 ppm). The NOEAL appeared to be 100 ppm
with small possible treatment-related increased body weight and fatty
liver seen at the LOAEL of 1000 ppm.
