A weighted combination of two routine laboratory measurements, i.e., fasting insulin and triglycerides, provides a simple means of screening for insulin resistance in the general population.

No abstract

To investigate the effects of meal frequency on plasma lipid and carbohydrate metabolism, 19 healthy normocholesterolemic free-living men and women consumed their usual diet as three or nine meals per day in random order for 2 wk each. There was no significant difference in macronutrient intake. Compared with the three-meal/d diet, nine meals per day reduced fasting plasma total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol by 6.5% (P < 0.005), 8.1% (P < 0.005), and 4.1% (P < 0.05), respectively. Body weight, fasting triglycerides, apolipoproteins A-I and B, and the LDL-HDL cholesterol ratios were not different for the two diets, as were 24-h urinary C peptide-creatinine ratios and insulin-glucose response to a glucose load. The insulin-glucose curve measured over 3 h in the evening after the evening meal was flatter for the nine meals, but the areas under the curves were not significantly different. Increasing meal frequency while maintaining a constant nutrient intake produces a small but significant decrease in LDL cholesterol in normolipidemic free-living subjects.

Objective: To compare two low fat diets one rich in walnuts on parameters of lipid metabolism in a group of hyperlipidaemic subjects. Design: A randomised cross over study. Setting: Department of Human Nutrition, University of Otago, Dunedin, New Zealand Subjects: Twenty one men with mean (s.d) levels of total and LDL cholesterol of 6.58 (0.60) and 4.63 (0.58) respectively. Interventions: For two periods of four weeks subjects were asked to consume two low fat diets (fat 30% total energy), one containing, on average, 78 gad walnuts. Walnuts obtained through Lincoln University and the Walnut Growers Group (South Canterbury). Results: Participants reported a higher total fat intake on the walnut diet (38% compared with 30% on the low fat diet P`0.01) The most consistent change in fatty acid pro®le of triacylglycerol, phospholipid and cholesterol ester on the walnut diet was a signi®cant (P`0.01) increase in linoleic acid. Triacylglycerol linolenate also increased signi®cantly (P`0.01). Total and LDL cholesterol were lower on both experimental diets than at baseline, 0.25 mmolal and 0.36 mmolal respectively on the walnut diet and 0.13 mmolal and 0.20 mmolal respectively on the low fat diet. High density lipoprotein cholesterol was higher on both the walnut and low fat diets when compared to baseline (0.15 mmolal and 0.12 mmolal, respectively). When comparing the walnut and low fat diets only apo B was signi®cantly lower (P`0.05) on the walnut diet. Conclusions: Despite an unintended increase in the total fat intake on the walnut diet, fatty acid pro®le of the major lipid fractions showed changes which might be expected to reduce risk of cardiovascular disease. The reduction of apolipoprotein B suggests a reduction in lipoprotein mediated risk, the relatively low myristic acid content of both diets perhaps explaining the absence of more extensive differences in lipoprotein levels on the two diets.

SUMMARYThe anhydrobiotic plant-parasitic nematode Ditylenchus dipsaci undergoes a decrease in permeability (the permeability slump) during the early stages of desiccation and this produces the slow rate of water loss necessary for its survival. There were no changes in annulation spacing, followed in individual nematodes by confocal microscopy, that would account for the permeability slump. Nile Red staining reveals that the surface of the nematode is coated with an extracuticular layer of lipid. This material can be seen in unstained desiccated nematodes where it forms an oil that adheres to the coverslip and to adjacent nematodes. The oily material leaves impressions on the coverslip (cuticle prints) after the nematode has detached upon rehydration. The presence of the surface lipid was confirmed using attenuated total reflection infrared spectroscopy. This material was shown to be a triglyceride and the proportion of fatty acids determined, using thin layer and gas chromatography. The production of the surface lipid material may be responsible for the permeability slump observed during the early phases of desiccation and its removal upon immersion in water may explain the paradox that cuticular permeability decreases during the permeability slump and yet desiccated nematodes are more permeable than are fully hydrated nematodes.