Biomedical subjects
D G Lindsay
Publications and source records attributed to D G Lindsay.
Zeranol--a 'nature-identical' oestrogen?
The use of implants of zeranol (alpha-zearalanol), a widely-used anabolic growth promoter, in food animals results in very low residues of this compound in the edible tissues. In comparison, residues of myco-oestrogens--specifically the beta-resorcylic acid lactones (RALs) such as zearalenone and its metabolites--commonly found as contaminants of cereals are much greater. Zeranol, the RALs and their metabolites are all closely related chemically, sterically and biologically. The biological effects of these compounds on reproduction, oestrogenicity, teratogenicity, genotoxicity and carcinogenicity are compared. No toxicological effects have been reported that cannot be attributed to the oestrogenic character of these molecules. In comparison with oestradiol, zeranol and the related myco-oestrogens are 100-1000 times less active hormonally. It is concluded that a likely no-observed-effect level (NOEL) for these compounds will be of the order of 0.05-0.1 mg/kg body weight/day. This would result in a safety margin greater than 500-fold between the expected dietary exposure to these compounds (considered together) and the likely NOEL. On the basis of exposure to zeranol alone, this margin of safety would increase to more than 35,000.
Duplicate diet study on fishing communities in the United Kingdom: mercury exposure in a "critical group".
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Reorganization of the UK total diet study for monitoring minor constituents of food.
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Receptor-binding region of insulin.
X-ray analysis, circular dichroism, receptor binding and biological potencies of chemically modified insulins suggest that the conformation of the insulin molecule is critical to the formation of both the zinc insulin hexamer and the insulin-receptor complex. Results are consistent with an insulin receptor-binding region including many of the hydrophobic residues important to dimerisation in addition to more polar surface residues. There is a further possibility of formation of an antiparallel sheet structure between the insulin and receptor molecules in the complex similar to that between monomers in the insulin dimer.
X-linked mental retardation without physical abnormality (Renpenning's syndrome) in sibs in an institution.
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Lipid compsition on comedones compared with that of human skin surface in acne patients.
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Estimation of the dietary intake of chemicals in food.
Methods for estimating the exposure of individuals to chemical substances present in the diet require information to be obtained about the patterns of food consumption in a community as well as the concentration of these chemicals in the diet. Methods of estimating food intakes using food diaries/weighed intake studies, dietary recall studies, food frequency and food disappearance methods are described. Their use, together with calculations derived from the data they provide are described to estimate normal and atypical food consumption patterns. The methods which have been used to estimate the exposure to existing chemicals in food are briefly reviewed and include total diet studies, selective studies on individual foods and duplicate portion studies. These methods are inappropriate for estimating the prospective intake of a chemical in food and the ways in which this issue may be approached, both nationally and internationally, are described with particular reference to the intakes of pesticide residues and food additives.