Role of adiponectin in the development of high fat diet-induced metabolic abnormalities in mice.

The adipokine adiponectin is decreased in severe obesity and is inversely associated with adipose mass. Adiponectin is associated with insulin sensitivity and cardioprotection. Obesity frequently results in the development of a "cardiometabolic syndrome" characterized by increased circulating insulin and leptin, and cardiac hypertrophy and dysfunction. This study examined if adiponectin-deficiency affects the development of metabolic and cardiac abnormalities in response to modest obesity. Mice were studied under normal conditions and with mild cardiac pressure-overload induced by abdominal aortic banding. After surgery, wild type and adiponectin-deficient mice were fed a high-fat diet for 8 weeks (45% energy from fat vs. 10%). In wild type mice the high-fat diet increased fat and whole body mass, which corresponded with elevated circulating insulin and leptin and a decrease the glucose/insulin ratio. On the other hand, in adiponectin-deficient mice the high-fat diet had less impact on body mass and no effect on fat mass, insulin, leptin, or glucose/insulin. There was modest cardiac hypertrophy with aortic banding, but no cardiac dysfunction or effects of adiponectin deficiency or diet. The results suggest that the increase in adipose mass, leptin and insulin induced by a high fat diet is dependent on adiponectin. The lack of accelerated cardiac hypertrophy and dysfunction in the adiponectin-deficient mice subjected to aortic banding and the high-fat diet suggest that adiponectin may not play a major role in protecting the heart during the early stages of diet-induced obesity.

Effect of tsetse control on trypanosome prevalence in livestock: problems of experimental design and statistical interpretation--a case study in northern Côte d'Ivoire.

As part of a study on livestock productivity under trypanosomosis risk in the region of Boundiali, northern Côte d'Ivoire, 21 herds of cattle (N'Dama, Baoulé and Zebu crosses) and 20 flocks of Djallonké and Djallonké x Sahel sheep were monitored monthly for body weight, packed red cell volume and trypanosomal parasitaemia over various periods between January 1984 and December 1992. A tsetse control campaign using biconical traps impregnated with alpha-cypermethrin started in December 1987. Tsetse control reduced the relative tsetse density by over 95% between 1988 and 1992, and this was associated with reductions in the prevalence of Trypanosoma congolense over the same period of over 90% both in sheep and cattle. Average reductions in the prevalence of T. vivax were lower, on average 68% in adults and 85% in young animals. Attempts were made in the design of the study to allow comparisons between controlled and uncontrolled areas; however, there were too many confounding and uncontrollable factors to allow such comparisons to be made. It was necessary, therefore, to compare data collected from all herds and flocks before and after the intervention, with the consequential difficulties in accounting for uncontrollable year-to-year variations in factors affecting trypanosome prevalence in livestock.