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Biomedical subjects

A Chisholm

Publications and source records attributed to A Chisholm.

5 recordsLinked to original sources

Should mono- or poly-unsaturated fats replace saturated fat in the diet?

The effects of diets differing in saturated, monounsaturated and polyunsaturated fatty acid composition (SAFA, MUFA and PUFA, respectively) on plasma lipoproteins and factor VIIc were investigated in 28 middle-aged men and women with mild to moderate hyperlipidaemia. The subjects were stabilized on a diet with a total fat content fairly typical of New Zealand, containing approximately 40% energy as fat, before entering a randomized cross-over trial of diets high in PUFA (20% energy; SAFA and MUFA 10% each) or a high MUFA diet (20% energy; SAFA and PUFA 10% each). After 6-week periods on each diet the subjects returned to a high SAFA diet. Body weight and blood pressure remained unchanged during the study. Total and LDL cholesterol, HDL cholesterol and the HDL2 subfraction were significantly lower on both the MUFA and the PUFA diet than on SAFA. However, there were no statistically significant differences in lipoprotein concentrations on the MUFA and PUFA diet. Factor VIIc concentrations were similar on the three diets. The proportion of PUFA in a MUFA diet appears to be a major determinant of the relative lipoprotein response to such a diet. In order to avoid a reduction in HDL-C when replacing SAFA with MUFA it may be necessary to ensure that PUFA does not provide more than about 8% total energy. Thus careful planning is needed to identify the most appropriate foods to replace those rich in SAFA in diets designed to reduce the lipoprotein-mediated risk of coronary heart disease.

Aged

Control of cell fate in the tail region of C. elegans by the gene egl-5.

The tail region of C. elegans contains a number of blast cell and neuron types that either are found only in the tail, or are different from more anterior homologues. In egl-5 mutants, the fates of many of these tail cells are abnormal or transformed to those of anterior homologues. The affected cells are related only by position and not by ancestry. egl-5 is also required for normal development of the somatic gonad and sex muscles in males. The function of egl-5 in all these tissues is cell autonomous. By genetic mapping, egl-5 lies very close to mab-5, a gene with an analogous role in the immediately anterior body region. egl-5 and mab-5 may constitute a 'mini-cluster' of regional determination genes, similar to those described in other animal phyla.

Animals

Dietary management of patients with familial hypercholesterolaemia treated with simvastatin.

The effect of diet on plasma lipids and lipoproteins was examined in 19 patients with familial hypercholesterolaemia treated with the HMGCoA reductase inhibitor, simvastatin. The study was a randomized double-blind cross-over trial of two diets: a low fat diet and a higher fat diet, and was performed to determine whether ongoing attention to diet is necessary for patients receiving this drug for the treatment of familial hypercholesterolaemia. Plasma cholesterol concentration was 6.5 per cent lower on the low fat diet than on the high fat diet. The difference was within the range predicted by the Jacobs modification of the Keys formula from the reported intake on the two diets. The fall on the low fat diet was principally accounted for by a reduction in low density lipoprotein cholesterol, although high density lipoprotein cholesterol and apolipoprotein A1 also fell. Patients taking HMGCoA reductase inhibitors for the treatment of familial hypercholesterolaemia respond to changes in dietary fat intake. They are thus likely to achieve further reduction in their coronary heart disease risk, and should remain on a low saturated fat low cholesterol diet even when taking these powerful lipid lowering drugs.

Adult