41 research outputs found

    Polynomial algorithm for finding the largest independent sets in graphs without forks

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    AbstractA fork is a graph that is obtained from K1,3 by subdividing one edge. It is known [6–8] that for K1,3-free graphs the problem of finding the largest independent set can be solved in a polynomial time. In this paper, we prove that this is also true for the wider class of fork-free graphs

    Effects of energy restriction on acute adrenoceptor and metabolic responses to exercise in obese subjects

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    Effects of energy restriction on acute adrenoceptor and metabolic responses to exercise in obese subjects. Kempen KP, Saris WH, Senden JM, Menheere PP, Blaak EE, van Baak MA. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. This study was intended to investigate the effects of energy restriction on the acute responses of platelet alpha 2- and lymphocyte beta 2-adrenoceptors to exercise in obese female subjects. Seven obese females were restricted to a low-energy formula diet (2.0 MJ/day) for 4 wk. As result of the diet, there was a 7.8-kg weight loss. No significant changes could be detected in sleeping and resting metabolic rate expressed per kilogram fat-free mass. Basal venous glucose, insulin, and norepinephrine levels decreased as a result of the diet, whereas free fatty acid values increased. Before the diet, 60 min of exercise (45% peak mechanical power) caused no alteration in the density of lymphocyte beta 2-adrenoceptors. At the end of 4 wk of dieting, the density was significantly increased in response to exercise, together with a higher thermogenic and lipolytic response and decreased venous insulin levels. Energy restriction resulted in an increased basal platelet alpha 2-adrenoceptor density, whereas exercise did not modify density and affinity of platelet alpha 2-adrenoceptors. The results indicate that adrenoceptor numbers can be modulated by energy restriction in obesity. Modulation of adrenoceptor density may play a role in increased exercise-induced lipolysis during energy restrictio

    Basal glucose metabolism and peripheral insulin sensitivity in equine pituitary pars intermedia dysfunction

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    Background: Glucocorticoids are suggested to precipitate laminitis and induce insulin resistance in horses. Hypothesis/Objectives: To assess insulin sensitivity and the basal amount of glucose metabolized in equine pituitary pars intermedia dysfunction (PPID). Animals and methods: The euglycaemic hyperinsulinaemic clamp (EHC) technique was performed in seven horses with a diagnosis of PPID based on the presence of hypertrichosis and positive dexamethasone suppression-test results comprising one gelding and six mares with a mean age of 21.1 +/- 5.8 (SD; range 15-34) years. Results were compared with those from five negative (healthy) controls comprising two geldings and two mares with a mean age of 10.0 +/- 2.5 (range 7-13) years and six positive (diseased) controls comprising two geldings and four mares with a mean age of 12.5 +/- 4.5 (range 8-21) years examined during the same period. Differences were assessed by means of the Mann-Whitney U test. Results: Mean basal rate of glucose metabolism (9.0 +/- 4.2 versus 16.0 +/- 5.2 micromol/kg BW/min; p = 0.030) and mean glucose metabolism rate-to-plasma insulin concentration ratio (2.9 +/- 1.6 versus 6.2 +/- 2.7 x 10(-6); p = 0.048) were significantly lower in PPID horses than in negative controls, respectively. No differences were found between both control groups. Conclusions and clinical importance: In horses suffering from PPID it seems important to reduce the insulin resistance, thereby potentially decreasing the risk of laminitis as being a major complication of equine PPID. Plasma glucose concentration following fasting might be considered in the screening of horses for PPID
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