It has been well demonstrated that the principal factor responsible for oxidative damage during exercise is the increase in oxygen consumption. However, other theoretical factors (acidosis, catecholamine autoxidation, ischemia-reperfusion syndrome, etc.) that are known to induce, in vitro, oxidative damage may also be operative during short-term supramaximal anaerobic exercise. Therefore, we hypothesized that short-term supramaximal anaerobic exercise (30-s Wingate test) could induce an oxidative stress. Lipid peroxidation markers [serum lipid radical production detected by electron spin resonance (ESR) spectroscopy and plasma malondialdehyde (MDA) levels detected by the thiobarbituric acid reactive substances (TBARS) method], as well as erythrocyte antioxidant enzyme activities [glutathione peroxidase (GPx), superoxide dismutase (SOD)] and erythrocyte glutathione (GSH) levels, were measured at rest, after the Wingate test and during the 40 min of recovery. The recovery of exercise was associated with a significant increase (x2.7) in lipid radical production detected by ESR spectroscopy, as well as with changes in the erythrocyte GSH level (-13.6%) and SOD activity (-11.7%). The paradoxical decrease in plasma TBARS (-23.7%) which was correlated with the peak power developed during the Wingate test ( r=-0.7), strongly suggests that such exercise stimulates the elimination of MDA. In conclusion, this study demonstrates that short-term supramaximal anaerobic exercise induces an oxidative stress and that the plasma TBARS level is not a suitable marker during this type of exercise.

The process of measles virus (MV) assembly and subsequent budding is thought to occur in localized regions of the plasma membrane, to favor specific incorporation of viral components, and to facilitate the exclusion of host proteins. We demonstrate that during the course of virus replication, a significant proportion of MV structural proteins were selectively enriched in the detergent-resistant glycosphingolipids and cholesterol-rich membranes (rafts). Isolated rafts could infect the cell through a membrane fusion step and thus contained all of the components required to create a functional virion. However, they could be distinguished from the mature virions with regards to density and Triton X-100 resistance behavior. We further show that raft localization of the viral internal nucleoprotein and matrix protein was independent of the envelope glycoproteins, indicating that raft membranes could provide a platform for MV assembly. Finally, at least part of the raft MV components were included in the viral particle during the budding process. Taken together, these results strongly suggest a role for raft membranes in the processes of MV assembly and budding.

. When expressed alone, the M but not N protein shows a low partitioning (around 10%) into rafts; this distribution is unchanged when all of the internal proteins, M, N, P, and L, are coexpressed. After infection with MGV, a chimeric MV where both H and F proteins have been replaced by vesicular stomatitis virus G protein, both the M and N proteins were found enriched in membrane rafts, whereas the G protein was not. These data suggest that assembly of internal MV proteins into rafts requires the presence of the MV genome. The F but not H glycoprotein has the intrinsic ability to be localized in rafts. When coexpressed with F, the H glycoprotein is dragged into the rafts. This is not observed following coexpression of either the M or N protein. We propose a model for MV assembly into membrane rafts where the virus envelope and the ribonucleoparticle colocalize and associate.

Thyroid hormones act directly on transcription by binding to TRalpha1, TRbeta1, and TRbeta2 nuclear receptors, regulating many aspects of postnatal development and homeostasis. To analyze precisely the implication of the widely expressed TRalpha1 isoform in this pleiotropic action, we have generated transgenic mice with a point mutation in the TRalpha1 coding sequence, which is expressed only after CRE/loxP-mediated DNA recombination. The amino acid change prevents interaction between TRalpha1 and histone acetyltransferase coactivators and the release of corepressors. Early expression of this dominant-negative receptor deeply affects postnatal development and adult homeostasis, recapitulating many aspects of congenital and adult hypothyroidism, except in tissues and cells where TRbeta1 and TRbeta2 are predominantly expressed. Both respective abundance and intrinsic properties of TRalpha1 and TRbeta1/2 seem to govern specificity of action.

BW loss during the marathon was inversely related to race finishing time in 643 marathon runners and was >3% in runners completing the race in less than 3 h. These data are not compatible with laboratory-derived data suggesting that BW loss greater than 2% during exercise impairs athletic performance. They match an extensive body of evidence showing that the most successful athletes in marathon and ultra-marathon running and triathlon events are frequently those who lose substantially more than 3-4% BW during competition.

Epidemiological data indicate that physical inactivity, a main factor of global energetic imbalance, is involved in the worldwide epidemic of obesity and metabolic disorders such as insulin resistance. Although the complex pathogenesis of insulin resistance is not fully understood, literature data accumulated during the past decades clearly indicate that the activation of the oxidative-inflammatory loop plays a major role. By activating the oxidative-inflammatory loop in insulin-sensitive tissues, fat gain and adipose tissue dysfunction likely contribute to induce insulin resistance during chronic and prolonged physical inactivity. However, in the past years, evidence has emerged showing that early insulin resistance also occurs after very short-term exposure to physical inactivity (1-7 days) without any fat gain or energetic imbalance. The possible role of liver disturbances or endothelial dysfunction is suggested, but further studies are necessary to really conclude. Inactive skeletal muscle probably constitutes the primary triggering tissue for the development of early insulin resistance. In the present review, we discuss on the current knowledge about the effect of physical inactivity on whole-body and peripheral insulin sensitivity, and how local inflammation and oxidative stress arising with physical inactivity could potentially induce insulin resistance. We assume that early muscle insulin resistance allows the excess nutrients to shift in the storage tissues to withstand starvation through energy storage. We also consider when chronic and prolonged, physical inactivity over an extended period of time is an underestimated contributor to pathological insulin resistance and hence indirectly to numerous chronic diseases.

Symptoms of delirium and severe nutritional impairment led patients to geriatric institutions. Therefore, these institutions need to implement policies that address both of these issues.

The purpose of this study is to examine the effects of the "Marathon of Sands" (MS), a 7-day, self-sufficient-diet, multi-stage running race across a section of the Moroccan desert, on body weight and plasma volume variation (PVV) and the relationship of these factors to performance in athletes who are well-trained in endurance. Sixteen MS runners agreed to participate in this study. Weight and body composition were measured and venous blood samples were taken before the first stage (D0), after the third stage (D3) and at the end of the MS (after the sixth stage: D6). Haematocrit and haemoglobin were used to calculate PVV at (D0, D3, and D6). No significant plasma volume decrease was observed throughout the race. Significant decreases in total body weight (BW), fat-free mass (FFM) and fat mass (FM) were observed in D3 and D6 (-4.3%, -3.5%, -0.8%; and -6.1%, -5%, -1.1%, respectively, for BW, FFM and FM at D3 and D6). This study clearly shows that, despite extreme conditions, the MS did not lead to a significant PV decrease in athletes well-trained in endurance. This study also supports the hypothesis that significant body weight loss may not systematically affect performances during long duration multiple-stage races.