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Ken Walder Carolyn R. Dascaliuc Paul A. Lewandowski Andrew J. Sanigorski Paul Zimmet Greg R. Collier 《Obesity (Silver Spring, Md.)》1997,5(3):193-200
Food intake was restricted to 75% of ad libitum levels in 37 male Psammomys obesus (Israeli Sand Rats) from the ages of 4 (weaning) to 10 weeks. Energy restriction reduced the mean body weight at 10 weeks by 29% compared with 44 ad libitum fed controls. Hyperglycemia was prevented completely in the food-restricted group, and mean blood glucose concentrations were significantly reduced (3.8 ± 0.2 vs. 5.5 ± 0.4 μmol/L; p<0.05) compared with control animals. Plasma insulin concentrations were also decreased significantly compared with ad libitum fed controls (105 ± 13 vs. 241 ± 29 mU/L;p<0.05). Although energy restriction prevented hyperglycemia from developing in 10-week-old P. obesus, 19% of the food restricted animals still developed hyperinsu-linemia. We concluded that hyperphagia between the ages of 4 to 10 weeks may be essential for the development of noninsulin-dependent diabetes mellitus in P. obesus, but that hyperinsulinemia may still occur in the absence of hyperphagia and hyperglycemia, suggesting a significant genetic influence on the development of hyperinsulinemia in this animal model. 相似文献
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J. Sherrod DeVerse Keith A. Bailey Greg A. Foster Vaishali Mittal Stuart M. Altman Scott I. Simon Anthony G. Passerini 《Journal of visualized experiments : JoVE》2012,(65)
Atherogenesis is potentiated by metabolic abnormalities that contribute to a heightened state of systemic inflammation resulting in endothelial dysfunction. However, early functional changes in endothelium that signify an individual''s level of risk are not directly assessed clinically to help guide therapeutic strategy. Moreover, the regulation of inflammation by local hemodynamics contributes to the non-random spatial distribution of atherosclerosis, but the mechanisms are difficult to delineate in vivo. We describe a lab-on-a-chip based approach to quantitatively assay metabolic perturbation of inflammatory events in human endothelial cells (EC) and monocytes under precise flow conditions. Standard methods of soft lithography are used to microfabricate vascular mimetic microfluidic chambers (VMMC), which are bound directly to cultured EC monolayers.1 These devices have the advantage of using small volumes of reagents while providing a platform for directly imaging the inflammatory events at the membrane of EC exposed to a well-defined shear field. We have successfully applied these devices to investigate cytokine-,2 lipid-3, 4 and RAGE-induced5 inflammation in human aortic EC (HAEC). Here we document the use of the VMMC to assay monocytic cell (THP-1) rolling and arrest on HAEC monolayers that are conditioned under differential shear characteristics and activated by the inflammatory cytokine TNF-α. Studies such as these are providing mechanistic insight into atherosusceptibility under metabolic risk factors. 相似文献
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Summary Transforming growth factor beta (TGF-) activates ATP citrate lyase in freshly isolated rat liver hepatocytes in a time dependent manner. Maximal stimulation of the enzyme occurred with less than thirty minutes of incubation of the cells with TGF-. The half maximal effect on the enzyme determined in hepatocytes incubated with TGF- for 10 min at 37°C was elicited by TGF- concentrations in the 10–11 – 10–12 M range. The potential role of TGF- stimulation of ATP citrate lyase activity in new membrane synthesis is discussed. 相似文献
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Testosterone, and winning and losing in human competition 总被引:9,自引:4,他引:5
Alan Booth Greg Shelley Allan Mazur Gerry Tharp Roger Kittok 《Hormones and behavior》1989,23(4):556-571
Testosterone and cortisol were measured in six university tennis players across six matches during their varsity season. Testosterone rose just before most matches, and players with the highest prematch testosterone had the most positive improvement in mood before their matches. After matches, mean testosterone rose for winners relative to losers, especially for winners with very positive moods after their victories and who evaluated their own performance highly. Winners with rising testosterone had higher testosterone before their next match, in contrast to losers with falling testosterone, who had lower testosterone before their next match. Cortisol was not related to winning or losing, but it was related to seed (top players having low cortisol), and cortisol generally declined as the season progressed. These results are consistent with a biosocial theory of status. 相似文献
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Sexual dimorphism in leg length among orb-weaving spiders: a possible role for sexual cannibalism 总被引:1,自引:0,他引:1
The degree and direction of sexual dimorphism across different species is commonly attributed to differences in the selection pressures acting on males and females. The extent of these differences is especially apparent in species that practise sexual cannibalism, where the female attempts to capture and eat a courting male. Here, we investigate the relationship between sexual dimorphism in size and leg length, sexual cannibalism and courtship behaviour in three taxonomic groups of orb-weaving spiders, using morphological data from 249 species in 36 genera. Females are larger than males in all three taxonomic groups, and males have relatively longer legs than females in both the Araneinae and Tetragnathidae. Across genera within each taxonomic group, male body size is positively correlated with both female body size and male leg length, and female body size is positively correlated with female leg length. Sexual size dimorphism is negatively correlated with relative male leg length within the Araneinae, but not within either the Tetragnathidae or the Gasteracanthinae. There was no negative correlation between sexual size dimorphism and relative female leg length in any taxonomic group. We argue that the relationship between sexual size dimorphism and relative male leg length within the Araneinae may be the result of selection imposed by sexual cannibalism by females. 相似文献
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Greg S. Spicer 《Journal of molecular evolution》1988,27(3):250-260
Summary The evolutionary and phylogenetic relationships of sevenDrosophila species groups (represented byD. melanogaster, D. mulleri, D. mercatorum, D. robusta, D. virilis, D. immigrans, D. funebris, andD. melanica) were investigated by the use of two-dimensional electrophoresis. The resulting phylogeny is congruent with the current views of evolution among these groups based on morphological characters and immunological distances. Previous studies indicated that the ability of one-dimensional electrophoresis to resolve relationships between distantly related taxa extended to about the Miocene [25 million years (Myr) ago], but the present study demonstrates that two-dimensional electrophoresis is a useful indicator of phylogeny even back to the Paleocene (65 Myr ago). In addition, two-dimensional electrophoresis is shown to be a useful technique for detecting slowly evolving structural proteins such as actins and tropomyosins. 相似文献
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