Biomedical Engineering Reference
In-Depth Information
30 males and 30 females hairless mice, the mice received UVR (2 hours
of simulated sunlight) in addition to methanol. The animals were
observed until 55 weeks of age. No skin tumors were observed in
the methanol only treated group at 55 weeks. Twenty-three animals
treated with methanol and UVR had skin tumors (carcinomas) out of 51
survivors at 55 weeks. Mice receiving retinoic acid and UVR or croton
oil plus retinoic acid had closed to 100% of the survivors with skin
tumors (multiple tumors per animal). Limited necropsies were pre-
formed. Hyperplasic, but no metastases, in the lymph nodes, spleen, and
salivary gland were noted in animals with tumors. The skin of the
methanol only treated mice and the methanol plus UVR-treated mice
appeared normal. Methanol by itself was not a tumor producer, but
methanol with 2 hours of simulated sunlight produced a tumor rate of
45%. Retinoic acid treatment on the other hand, produced multiple
tumors per animal in about 100% of the mice (Forbes et al., 1979).
A study to evaluate the dermal toxicity and carcinogenicity of
malonaldehyde was conducted at the Eppley Institute (Apaja, 1980).
Malonaldehyde (MDA), which is a product of oxidative lipid deteriora-
tion in rancid beef, had previously reported to be carcinogenic in a two-
stage skin-painting study using acetone as a solvent. Malonaldehydewas
found to be too unstable in acetone, so methanol, which helped stabilize
MDA, was used in the Eppley study. MDAwas prepared for this study as
a dilute solution, that is more stable than pure MDA, by dissolving
malonaldehyde bis diethylacetal and 6 N HCL in water. Methanol was
released by the hydrolysis of the acetal groups and MDAwas produced.
In the Eppley skin-painting study, the control group was treated with
0.05ml of methanol (containing 0.625% methanol in water). Groups of
40 female shaved Swiss mice were treated with various levels of MDA
andmethanol control three times aweek for life. Themicewere observed
daily (dermal irritation), weighed weekly, and sacrificed when mori-
bund. Complete autopsy were conducted and section of skin, lung, liver,
spleen, pancreas, kidney, adrenal glands, esophagus, stomach, small and
large intestine, rectum urinary bladder, uterus and ovaries, vesicular
glands, and any gross lesions including tumors.
There was no treatment-related skin irritation in any group. Because
of lower than expected doses in the lower MDA groups due to technical
