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Biomedical subjects

M J Wolfe

Publications and source records attributed to M J Wolfe.

4 recordsLinked to original sources

DNA alterations and enzyme activities in Japanese medaka (Oryzias latipes) exposed to diethylnitrosamine.

Several molecular and biochemical markers of genotoxicity were adapted for measurement in the medaka, and were used to describe the effects of treatment of the organism with diethylnitrosamine (DEN). DEN treatment inhibited the activity of a detoxication enzyme activity (ethoxyresorufin-O-deethylase) and increased the activity of glutathione-S-transferase. This pattern of response has been described in preneoplastic rodent cells. No O6-ethyl guanine adducts were detected, and a slight, but statistically significant, increase in DNA strand breaks was observed. These results are consistent with the hypothesis that prolonged exposure to high levels of DEN induced alkyltransferase activity which enzymatically removes any O6-ethyl guanine adducts but does not result in strand breaks or hypomethylation of the DNA such as might be expected from excision repair of chemically modified DNA.

Animals

Seasonal prevalence of skin tumors from walleye (Stizostedion vitreum) from Oneida Lake, New York.

A seasonal survey of skin tumor prevalence in walleyes (Stizostedion vitreum) was conducted during the ice-free period on Oneida Lake, New York in 1986. During the survey, 1,028 walleyes were collected and examined for the presence of lymphocystis disease, dermal sarcoma, discrete epidermal hyperplasia and diffuse epidermal hyperplasia. Skin growths were high in prevalence in early spring, low in prevalence during the summer, and again high in prevalence in the fall. Lymphocystis disease and dermal sarcoma were more frequently observed than either discrete or diffuse epidermal hyperplasia. Histologically, a moderate to severe inflammatory response was associated with dermal sarcoma in the early spring and late spring but not in the fall. Regardless of the time of year, varying degrees of inflammatory response were seen associated with lymphocystis disease. Samples were inadequate to assess seasonal trends in incidence of discrete and diffuse epidermal hyperplasia.

Animals

A lymphosarcoma in an Atlantic salmon (Salmo salar).

A lymphosarcoma that appeared to be of thymic origin and of lymphoblastic type was found in a 3.5-yr-old Atlantic salmon (Salmo salar). The fish was from a population of 60 broodfish maintained at a research fish laboratory. A large tumor mass was found under the left operculum. Small tumor nodules were found on the swim bladder and in the abdominal adipose tissue. The location of this neoplasm differed from those of previously described tumors in this fish species.

Animals