No abstract

The aim of this study was to evaluate whether high-intensity endurance training would alleviate exercise-induced oxidative stress. Nine untrained male subjects (aged 19-21 years) participated in a 12-week training programme, and performed an acute period of exhausting exercise on a cycle ergometer before and after training. The training programme consisted of running at 80% maximal exercise heart rate for 60 min.day-1, 5 days.week-1 for 12 weeks. Blood samples were collected at rest and immediately after exhausting exercise for measurements of indices of oxidative stress, and antioxidant enzyme activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT)] in the erythrocytes. Maximal oxygen uptake (VO2max) increased significantly (P < 0.001) after training, indicating an improvement in aerobic capacity. A period of exhausting exercise caused an increase (P < 0.01) in the ability to produce neutrophil superoxide anion (O2.-) both before and after endurance training, but the magnitude of the increase was smaller after training (P < 0.05). There was a significant increase in lipid peroxidation in the erythrocyte membrane, but not in oxidative protein, after exhausting exercise, however training attenuated this effect. At rest, SOD and GPX activities were increased after training. However, there was no evidence that exhausting exercise enhanced the levels of any antioxidant enzyme activity. The CAT activity was unchanged either by training or by exhausting exercise. These results indicate that high-intensity endurance training can elevate antioxidant enzyme activities in erythrocytes, and decrease neutrophil O2.- production in response to exhausting exercise. Furthermore, this up-regulation in antioxidant defences was accompanied by a reduction in exercise-induced lipid peroxidation in erythrocyte membrane.

Although mouse liver F4/80(+) Kupffer cells consist of cytokine-producing CD11b(+) cells and phagocytic CD68(+) cells, an undefined CD11b(-) CD68(-) subset (30%) also exists. We herein demonstrate a more fundamental classification by adding CD32 (FcγRII), which covers most liver F4/80(+) cells and the distinct functions of them. Among the F4/80(+) cells, 50%, 40%, and 30% of cells were CD32(+), CD68(+), and CD11b(+), respectively, and one-half of the CD68(+) cells coexpressed CD32. CD68(+) and CD32(+) cells, but not CD11b(+) cells, expressed a phagocytosis-related CRIg. Gy (6) irradiation depleted liver CD11b(+) cells and those in the spleen, bone marrow, and peripheral blood but not liver CD32/CD68(+) cells. Transfer of bone marrow cells into the irradiated mice reconstituted liver CD11b(+) cells. Conversely, clodronate pretreatment depleted only liver CD32/CD68(+) cells but not liver CD11b(+) cells and peripheral blood or spleen CD11b(+) monocytes/macrophages. Moreover, the CD32(+) cells might be precursors of CD68(+) cells, as a large proportion of CD32(+) cells expressed the c-kit (CD117), and CD34 and CD32(+) cells acquired CD68 immediately after bacteria administration. CD32/CD68(+) cells, but not CD11b(+) cells, expressed resident macrophage-specific MerTK and CD64 (FcγRI). Challenge with Staphylococcus aureus or liver metastatic EL-4 tumor cells indicated that the CD68(+) subset is engaged in systemic bactericidal activity, whereas the CD11b(+) subset is pivotal for liver antitumor immunity. Human liver CD14(+) Kupffer cells could also be classified into three similar subsets. These results suggest that liver CD68(+) Kupffer cells and CD11b(+) Kupffer cells/macrophages are developmentally and functionally distinct subsets.

Nelumbo nucifera Gaertn. (Nymphaceae) has been used for various medicinal purposes as in Chinese herbal medicine. In particular, the leaves are known for diuretic and astringent properties, and are used to treat obesity. During our search for a plant-derived anti-obesity agent from natural products, we have found that a 50% ethanol (EtOH) extract prepared from the leaves of N. nucifera (NN) stimulated lipolysis in the white adipose tissue (WAT) of mice and that the beta-adrenergic receptor (beta-AR) pathway was involved in this effect. In subsequent experiments, dietary supplementation of NN resulted in a significant suppression of body weight gain in A/J mice fed a high-fat diet. Bioassay-guided fractionation and repeated chromatography of NN has led to the isolation and identification of quercetin 3-O-alpha-arabinopyranosyl-(1-->2)-beta-galactopyranoside (1), rutin (2), (+)-catechin (3), hyperoside (4), isoquercitrin (5), quercetin (6) and astragalin (7). Of these, compounds 1, 3, 4, 5 and 7 exhibited lipolytic activity, especially in visceral adipose tissue. Our results indicate that the effects of NN in preventing diet-induced obesity appear to be due to various flavonoids and that the activation of beta-AR pathway was involved, at least in part.

Bacterial infections, including surgical site infections (SSI), are a common and serious complication of diabetes. Staphylococcus aureus, which is eliminated mainly by neutrophils, is a major cause of SSI in diabetic patients. However, the precise mechanisms by which diabetes predisposes to staphylococcal infection are not fully elucidated. The effect of insulin on this infection is also not well understood. We therefore investigated the effect of insulin treatment on SSI and neutrophil function in diabetic mice. S. aureus was inoculated into the abdominal muscle in diabetic db/db and high-fat-diet (HFD)-fed mice with or without insulin treatment. Although the diabetic db/db mice developed SSI, insulin treatment ameliorated the infection. db/db mice had neutrophil dysfunction, such as decreased phagocytosis, superoxide production, and killing activity of S. aureus; however, insulin treatment restored these functions. Ex vivo treatment (coincubation) of neutrophils with insulin and euglycemic control by phlorizin suggest that insulin may directly activate neutrophil phagocytic and bactericidal activity independently of its euglycemic effect. However, insulin may indirectly restore superoxide production by neutrophils through its euglycemic effect. HFD-fed mice with mild hyperglycemia also developed more severe SSI by S. aureus than control mice and had impaired neutrophil phagocytic and bactericidal activity, which was improved by insulin treatment. Unlike db/db mice, in HFD mice, superoxide production was increased in neutrophils and subsequently suppressed by insulin treatment. Glycemic control by insulin also normalized the neutrophil superoxide-producing capability in HFD mice. Thus, insulin may restore neutrophil phagocytosis and bactericidal activity, thereby ameliorating SSI.T he number of patients with diabetes mellitus has increased greatly worldwide (8,48). It is well known that diabetic patients are more prone to bacterial infections, including surgical site infections (SSI), than healthy individuals. Although many clinical reports have demonstrated that glycemic control reduces the risk of infections, the precise mechanisms by which diabetes predisposes to infections are not well understood (2, 21, 38). Control of bacterial infections has become more important for diabetic patients than in the past, because of the increase in diabetic patients and their susceptibility to infections. Foot infections following skin ulceration are also common causes of hospitalization for diabetic patients (6). These infectious complications seriously impair prognoses for diabetic patients (44).Gram-positive bacteria cause more than half of cases of diabetesrelated wound infections. Especially, Staphylococcus aureus is a major pathogen in these infections (44). Methicillin-resistant S. aureus (MRSA) also has become prevalent among both nosocomial and community-acquired infections in diabetic patients (44). Neutrophils play crucial roles in eliminating bacteria, including S. aureus, from hosts (22). Therefore, neutrophil ...