The agouti gene product inhibits lipolysis in human adipocytes via a Ca2+-dependent mechanism

Overexpression of the murine agouti gene results in obesity. The human homologue of agouti is expressed primarily in human adipocytes, and we have shown recombinant agouti protein to increase adipocyte intracellular Ca2+([Ca2+]i) and thereby stimulate lipogenesis. However, since recent data demonstrate that increasing adipocyte [Ca2+]i may also inhibit lipolysis, we have investigated the role of agouti-induced [Ca2+]i increases in regulating lipolysis in human adipocytes. Short-term (1 h) exposure to recombinant agouti (100 nM) protein had no effect on basal lipolysis, although longer term treatment (24 h) caused a 60% decrease in basal lipolysis (P<0.0001). Short-term agouti treatment totally inhibited ACTH-induced lipolysis (P<0.05). Since melanocortin receptors (MCR) are involved in some actions of agouti, we next determined whether agouti's antilipolytic effect is exerted through competitive antagonism of the ACTH receptor (MCR-2). Forskolin (1 microM), an adenylate cyclase activator, induced a 48% increase in lipolysis in human adipocytes (P<0.05); this effect was reversed by 100 nM agouti (P<005), demonstrating that the antilipolytic effect of agouti is distal to the ACTH receptor. To determine the role of [Ca2+]i in the antilipolytic effect of agouti, human adipocytes were treated with KCl or arginine vasopressin to stimulate voltage- and receptor-stimulated Ca2+ influx, respectively. Both agents caused inhibition of forskolin-induced lipolysis (P<0.005). Furthermore, agouti's antilipolytic effect was also blocked by the Ca2+ channel blocker nitrendipine. These data demonstrate that agouti exerts a potent antilipolytic effect in human adipocytes via a Ca2+-dependent mechanism. This effect, combined with agouti-induced lipogenesis, represents a coordinate control of adipocyte lipid metabolism that may contribute to an agouti-induced obesity syndrome.     

Antimicrobial susceptibilities of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens spp. isolated in Spain

The susceptibilities of 143 Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens isolates to 18 antimicrobial agents were tested. All P. gingivalis isolates were susceptible. In contrast, some Prevotella spp. (17%) were resistant to beta-lactams, erythromycin, clindamycin, or tetracycline and carried resistance genes, ermF or tetQ, or beta-lactamases.     

Effect of essential and nonessential fatty acids in complex mixture on fatty acid composition of liver lipids

Linoleate, linolenate, arachidonate, docosahexenoate and six other fatty acids were major components of 24 ester preparations fed as 5% of the diet for 60 days to groups of male white rats. The experiment was designed so as to provide that all major fatty acid components were independent of each other in the sense that the intake of each was poorly correlated with the intake of any of the others. Fatty acid compositions of liver lipids were determined and were related to the composition of the diet lipids. Linolenate and docosahexaenoate contents of diet and tissue revealed the same relationships reported previously from experiments in which individual pure acid esters were added to a fat-free diet. Linoleate, when fed in lipid mixtures, was more effective in raising the linoleate concentration in liver lipids than when fed alone, but this increase did not change the shape of the dose-response curve or the estimated nutritional requirement. Large amounts of fish oil in the diet tended to depress the arachidonate concentration in tissue lipids.     

一种可调的全密封大功率氦-氖激光管

本文介绍一种采用玻璃封接工艺制作的全密封大功率氦-激光管。该管系全内腔可调结构，腔长1米，在不同加磁场，不用氦-3的条件下，可在6328A输出40mW以上的多模功率，寿命可保用三年。     

Prognostic significance of vascular invasion in colorectal cancer of Dukes' B class

To further characterize important prognostic factors in colorectal cancer of the Dukes' B class the pathologic material from 143 Dukes' B patients was reviewed for the presence of lymphatic and/or blood vessel invasion and correlated with the postoperative tumor-free interval and overall length of survival. In 27 patients with vascular invasion within the bowel wall, both the tumor-free interval and the overall survival time were not significantly different from the same parameters in 116 patients without vascular invasion (P = 0.28, P = 0.12 respectively). These data suggest that vascular invasion within the bowel wall per se is not an important prognostic factor among patients with colorectal cancer of the Dukes' B class.