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D E Stevenson

Publications and source records attributed to D E Stevenson.

70 records · Page 4Linked to original sources
PubMed1967

Toxicological studies with the molluscicide N-tritylmorpholine.

The mammalian and avian toxicities of N-tritylmorpholine (Frescon, WL 8008), a compound active against the snails that are the intermediate hosts of schistosomes, are reported. The acute oral, acute percutaneous, dermal irritation, sensitization and subacute toxicity methods used are described and the results obtained are discussed.The acute oral toxicity of N-tritylmorpholine ranges from 40 mg/kg to over 4000 mg/kg, depending on the formulation tested. The lower toxicity rating is closely related to the toxicity of the solvent rather than to that of the molluscicide. Administered percutaneously to rats, N-tritylmorpholine produced no ill-effects at 1000 mg/kg. N-Tritylmorpholine fed in the diets of rats at 100 ppm for 90 days produced no significant effect.It is concluded that N-tritylmorpholine will not constitute a hazard to people who ingest or apply the material under normal conditions of use.

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PubMedDate not supplied

The carcinogenic response in mice to the topical application of propane sultone to the skin.

The carcinogenic effects of limited and repeated skin applications of propane sultone were investigated in three strains of mice, CF1, C3H and CBah (a hairless strain). Propane sultone was shown to be carcinogenic when given as a single application of a 25% w/v solution in toluene and also following twice weekly application of a 2.5% w/v solution for up to 58 weeks. More limited exposure to 2.5% w/v solutions of propane sultone resulted in a few skin tumours, although the incidences were not statistically significant. Most neoplasms were papillomas or carcinomas, although a small number of mesenchymal tumours of dermal origin also developed. No skin neoplasms were found in any control mice. The skin application of propane sultone was associated with a statistically significant increase in the incidence of systematic neoplasia in CFl and C3H mice. The exposed CFl mice had a higher incidence of neoplasms of lymphoreticular and lung origin, while female C3H mice showed a higher incidence of mammary gland and uterine tumours. In mice exposed to beta-propiolactone as a positive control, neoplasms developed at the site of application but, there was no evidence of increased systemic neoplasis in contrast to the findings with ptopane sultone.

Animals↗
PubMedDate not supplied

Role of oxidative stress in the mechanism of dieldrin's hepatotoxicity.

The production of reactive oxygen species (ROS) by toxic chemicals has been implicated in acute and chronic disease states, including cancer. This increase in cellular ROS can lead to a state of oxidative stress. Many compounds selectively induce hepatic tumors in mice but not rats. The mechanism for the induction of hepatic cancer by these compounds and the observed species selectivity of this effect are not known but may be related to the induction of oxidative stress. Dieldrin is one such compound and is used in the present study to characterize the relationship between oxidative stress and the observed selective hepatotoxicity of dieldrin in mice. It was found that dieldrin induced oxidative stress in the mouse but not the rat, and the observed oxidative stress correlated with the induction of DNA S-phase synthesis. This evidence suggests that the induction of oxidative stress may be a mechanism by which dieldrin and other mouse specific compounds selectively induce their hepatic toxic effects in mice.

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