Biomedical Engineering Reference
In-Depth Information
problems, only the top MDA group (1.2%) and the methanol control
were kept for a lifetime. There was no difference in survival or body
weight between the top dose MA group and the methanol control. No
skin tumors were observed, but the top MDA group had a significantly
larger number of malignant lymphomas (17) than the methanol controls
(6). The lymphoma incidence was within the normal historical range at
Eppley. It should be noted that no water only control group was included
in this experiment. There were no differences between the top dose
MDA group and the methanol control in any other tumor incidences
(Apaja, 1980).
8.3 POSSIBLE MECHANISMS
8.3.1 Genotoxicity
8.3.1.1 In Vitro
Methanol did not show activity in the Salmonella test
with or without metabolic activation in Salmonella strain TA 1535, TA
1537, TA 1538, TA 98, and TA 100 in several studies (Simmon et al.,
1977; Deflora, 1981; NEDO, 1986). Methanol is also negative in
Escherichia coli (WP2 WP 67 CM 871), Spombe ade 6 locus and
Neurospora crassa tests with and without activation (IPCS, 1997).
Methanol did not show activity in E. coli (WP2uvrA) (Shimizu et al.,
1995). Methanol induced chromosomal malsegregation in Aspergillus
niduians (Crebelli et al., 1989). Methanol does not cause sister chro-
matid exchange in Chinese hamster cells (IPCS, 1997; NEDO, 1986).
Methanol was also negative in cell transformation assays (Syrian
hamster embryo clonal system and Rausher leukemia virus infected
rat embryo cells) (IPCS, 1997). Methanol was negative in the L5178Y
mouse lymphoma cells without activation, but positive with activation
(McGregor et al., 1988). Heidelberger et al. (1983) found methanol
negative in Syrian hamster cell (SHE) and did not increase transforma-
tion in SHE with and without transformation by simian adenovirus.
8.3.1.2 In Vivo
Cytogenic effects of methanol in blood erythrocytes,
lung cells, and testicular germ cells of mice were evaluated following
exposure to 800 or 4000 ppm for 6 hours per day for 5 days. No increase
