The effect of unbound palmitic acid (PA) at plasma physiological concentration range on reactive oxygen species (ROS) production by cultured rat skeletal muscle cells was investigated. The participation of the main sites of ROS production was also examined. Production of ROS was evaluated by cytochrome c reduction and dihydroethidium oxidation assays. PA increased ROS production after 1 h incubation. A xanthine oxidase inhibitor did not change PA-induced ROS production. However, the treatment with a mitochondrial uncoupler and mitochondrial complex III inhibitor decreased superoxide production induced by PA. The importance of mitochondria was also evaluated in 1 h incubated rat soleus and extensor digitorum longus (EDL) muscles. Soleus muscle, which has a greater number of mitochondria than EDL, showed a higher superoxide production induced by PA. These results indicate that mitochondrial electron transport chain is an important contributor for superoxide formation induced by PA in skeletal muscle. Results obtained with etomoxir and bromopalmitate treatment indicate that PA has to be oxidized to raise ROS production. A partial inhibition of superoxide formation induced by PA was observed by treatment with diphenylene iodonium, an inhibitor of NADPH oxidase. The participation of this enzyme complex was confirmed through an increase of p47(phox) phosphorylation after treatment with PA.

This work was undertaken to provide further insight into the role of mammalian target of rapamycin complex 1 (mTORC1) in skeletal muscle regeneration, focusing on myofiber size recovery. Rats were treated or not with rapamycin, an mTORC1 inhibitor. Soleus muscles were then subjected to cryolesion and analyzed 1, 10, and 21 days later. A decrease in soleus myofiber cross-section area on post-cryolesion days 10 and 21 was accentuated by rapamycin, which was also effective in reducing protein synthesis in these freeze-injured muscles. The incidence of proliferating satellite cells during regeneration was unaltered by rapamycin, although immunolabeling for neonatal myosin heavy chain (MHC) was weaker in cryolesion+rapamycin muscles than in cryolesion-only muscles. In addition, the decline in tetanic contraction of freeze-injured muscles was accentuated by rapamycin. This study indicates that mTORC1 plays a key role in the recovery of muscle mass and the differentiation of regenerating myofibers, independently of necrosis and satellite cell proliferation mechanisms.

O treinamento físico, de intensidade moderada, melhora os sistemas de defesa, enquanto que o treinamento intenso causa imunossupressão. Os mecanismos subjacentes estão associados à comunicação entre os sistemas nervoso, endócrino e imunológico, sugerindo vias autonômicas e modulação da resposta imune. Células do sistema imune, quando expostas a pequenas cargas de estresse, desenvolvem mecanismo de tolerância. Em muitos tecidos tem-se demonstrado que a resposta a situações agressivas parece ser atenuada pelo treinamento físico aplicado previamente, isto é, o treinamento induz tolerância para situações agressivas/estressantes. Nesta revisão são relatados estudos sugerindo os mecanismos adaptativos do sistema imunológico em resposta ao treinamento físico.

RESUMOOs ácidos graxos (AG) representam uma fonte importante de energia durante exercícios de intensidade leve ou moderada, e principalmente naqueles de duração prolongada. A utilização dos AG pelos músculos esqueléticos depende de passos importantes como a mobilização, transporte via corrente sangüínea, passagem pelas membranas plasmática e mitocôndrial, β-oxidação e, finalmente, a oxidação no ciclo de Krebs e atividade da cadeia respiratória. O exercício agudo e o treinamento induzem adaptações que possibilitam maior aproveitamento dos AG como fonte de energia, ao mesmo tempo em que o glicogênio muscular é preservado. Contudo, as tentativas de manipulação da dieta e suplementação com agentes ativos para aumentar a mobilização e utilização dos AG durante o exercício não apresentam resultados conclusivos. Nesse trabalho, a hipótese de que o ciclo de Krebs é o fator limitante da utilização de ácidos graxos pelo tecido muscular no exercício prolongado é apresentada. ABSTRACTThe Krebs Cycle as Limiting Factor for Fatty Acids Utilization During Aerobic Exercise. Fatty acids are important fuels for muscle during moderate and prolonged exercise. The utilization of fatty acids by skeletal muscle depends on important key steps such as lipolysis in the adipose tissue, plasma fatty acids transport, and passage through plasma and mitochondrial membranes, β-oxidation, and finally oxidation through the Krebs cycle and respiratory chain activity. Acute exercise and exercise training induce adaptations that lead to an increase in fatty acid oxidation. As a result muscle glycogen is preserved. Nevertheless, diet manipulation and supplementation with lipolytic agents that raise fatty acids mobilization and oxidation during exercise failed to show beneficial results on exercise performance. The hypothesis that Krebs cycle is a limiting factor for fatty acid oxidation by the skeletal muscle during prolonged exercise is presented herein.

We determined the prevalence of metabolic syndrome (MetS) among military police officers (MPOs) from the radio patrol program of the Military Police of Sao Paulo State (PMESP). Towards this goal, we analyzed the following characteristics: shift duty (daytime or nighttime patrol), service length in the PMESP, education level attained, weekly alcohol consumption, smoking, and physical activity of 93 MPOs. The MPO groups were created based on work shift [daytime (n=48) or nighttime (n=45)], and years of MPO experience [≤3 years (n=48) or ≥10 years (n=45)]. The overall prevalence of MetS among the 93 MPOs was 43%. There was a higher prevalence of MetS in the group with ≥ten years (53.3%) than that with ≤three years (33.3%); so, 1,6 times higher. The more prevalent MetS indicators (n=93) included waist circumference (76.3%), hypertension (55.9%), reduced plasma HDL-cholesterol levels (44%), hypertriglyceridemia (32.2%), and hyperglycemia (20.4%). Greater waist circumference, hypertension, hypertriglyceridemia, higher glycated hemoglobin A1c (HbA1c) levels, and MetS itself were associated with the service length (i.e., ≥ten years). The work shift was not associated with any MetS indicator. Those who were overweight or obese were 2.2. times more likely to develop MetS. Hypertriglyceridemia, the best indicator of the MetS, increased the chance of developing MetS by 16 times. Conclusion: MPOs exhibit a high prevalence of MetS, associated with the years of service and age.

Phosphate-dependent glutaminase (PDG) activity, a key enzyme of glutamine metabolism, was determined in neutrophils obtained from the intra-peritoneal cavity (PC) or bronchoalveolar space (BAS) after administration of 1 ml or 100 microl, respectively of saline, glycogen solution (1%) or lipopolysaccharide (LPS 0.1 mg (100 microl)(-1)). Neutrophils were obtained by lavage of both sites with 20 ml saline 24 h after the administration of the stimuli. Glycogen and LPS, depending on the site the cells were obtained from, differently modulated PDG activity. Cells from BAS stimulated by glycogen or LPS had raised PDG activity to 30.5 +/- 5.2 and 42.7 +/- 12.1 nmol min(-1) mg(-1) protein, respectively, when compared with saline (9.1 +/- 0.9 nmol min(-1) mg(-1) protein); mean +/- SEM. On the other hand, cells from PC showed different PDG activity: 52.0 +/- 12.6 nmol min(-1) mg(-1) for saline, 36.5 +/- 9.5 nmol min(-1) mg(-1) for glycogen, and 76.6 +/- 11.2 nmol min(-1) mg(-1) for LPS; mean +/- SEM. Therefore, PDG activity varies with the site from which neutrophils are obtained and the stimulus imposed. The effect of glutamine on nitric oxide (NO) and tumour necrosis factor (TNF) production by peritoneal neutrophils, obtained after glycogen administration, cultured in the presence of LPS (0.5 microg ml(-1)) was also examined. The addition of glutamine at concentrations varying from 2 to 20 mM did not markedly affect NO production. Glutamine alone at 2 mM did not modify the production of TNF but in the presence of LPS caused a significant decrease. So, glutamine may preserve the function of neutrophils during infections and injuries.

The health promotion efficacy of a dietary regimen and physical activity guidance program applied to the São Paulo state military ppre-obese policemen exhibitedolice working in São Paulo city was investigated. The guidance program consisted of the delivery of a 10-minute talk on healthy nutritional habits and the beneficial effects of a regular physical activity practice for each volunteer personally. The physical fitness parameters related to the health of the volunteers were evaluated before and eight weeks after the interventional program. The study included 58 policemen working in São Paulo city, aged 34.9 ± 0.8 years (mean ± SEM). The application of the guidance program could decrease body fat percentage (BFP) (by 5.7%), abdominal circumference (ABC) (by 1.1%), and systolic blood pressure (SBP) (by 2.4%), and increase flexibility (FLEX) (by 8.8%) and abdominal resistance (ABR) (by 5.2%). A change in physical activity behavior was also reported. Increases in the number of volunteers in very active (VA) (3.45%), active (ACT) (10.35%), and irregular active A (IRA) (5.17%) groups, and reductions in irregular active B (IRB) (13.79%) and sedentary (SED) (5.17%) groups were found. The policemen were classified (before-after) as obese (29.3%-24.1%) and pre-obese (39.7%-43.1%). Foty-three percent of preobese policemen exhibited more daily physical activity after the guidance program implementation. The guidance program was effective in increasing the adherence of pre-obese policemen to the physical activity practice, reduced the percentage of body fat and abdominal circumference, and improved lower limbs flexibility and abdominal muscle resistance.

SummaryBackground: the purpose of this study was to verify the validity of respiratory compensation threshold (RCT) measured during a new single judo specific incremental test (JSIT) for aerobic demand evaluation. Methods: to test the validity of the new test, the JSIT was compared with Maximal Lactate Steady State (MLSS), which is the gold standard procedure for aerobic demand measuring. Eight well-trained male competitive judo players (24.3 ± 7.9 years; height of 169.3 ± 6.7cm; fat mass of 12.7 ± 3.9%) performed a maximal incremental specific test for judo to assess the RCT and performed on 30-minute MLSS test, where both tests were performed mimicking the UchiKomi drills. Results: the intensity at RCT measured on JSIT was not significantly different compared to MLSS (p=0.40). In addition, it was observed high and significant correlation between MLSS and RCT (r=0.90, p=0.002), as well as a high agreement. Conclusions: RCT measured during JSIT is a valid procedure to measure the aerobic demand, respecting the ecological validity of Judo. KEY WORDS: ergometer, domain intensity, field test, metabolic demand, second ventilatory threshold.