Biochemical and Hormone Markers in Firefighters: Effects of "Search, Rescue, and Survival Training" and Its Recovery.

ABSTRACT: Ponce, T, Mainenti, MRM, de Barros, T, Cahuê, FLC, Fernanda, C, Piazera, BKL, Salerno, VP, and Vaisman, M. Biochemical and hormone markers in firefighters: effects of "search, rescue, and survival training" and its recovery. J Strength Cond Res 38(4): e189-e201, 2024-This study aimed to evaluate the hormonal and biochemical responses in military firefighter cadets to a search, rescue, and survival training (SRST) course. Forty-three male volunteers participated in the SRST over 15 days consisting of intense physical effort, sleep deprivation, and a survival period with food deprivation. At 3 timepoints (baseline, SRST, and 1 week rec), subjects submitted to blood collections, body composition examinations, physical performance evaluations, and cognitive function tests. After the SRST, lower values were registered for testosterone (764.0; 565.1-895.0 to 180.6; 133.6-253.5 ng·dl -1 ) and insulin-like growth factor-1 (IGF-1) (217; 180-238 to 116; 102-143 ng·ml -1 ). Increases were observed for cortisol (9.7; 8.2-11.7 to 18.3; 16.5-21,2 µg·dl -1 ), growth hormone (GH) (0.11; 0.06-0.20 to 2.17; 1.4-3.4 ng·ml -1 ), CP, GSSG, lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase as well as the antioxidant response of superoxide dismutase and glutathione peroxidase. The values of gamma-glutamyl transferase were reduced. After 1 week of recovery, levels of GH, creatine kinase, GSH, and GSSG returned to baseline values ( p < 0.05). Vertical jump performance presented a regular positive correlation with testosterone (rho = 0.56 and p < 0.0001) and a strong negative correlation with cortisol (rho = -0.61 and p < 0.0001). Body fat showed a regular and positive correlation with both testosterone and IGF-1. We conclude that participation in the SRST caused significant hormonal and biochemical changes in individuals that correlated with a loss in physical performance. Importantly, the results suggest the need for longer recovery times before a return to normal military duties.

Acute Hormone Responses Subsequent to Agonist-Antagonist Paired Set vs. Traditional Straight Set Resistance Training.

Miranda, H, de Souza, JAAA, Scudese, E, Paz, GA, Salerno, VP, Vigário, PdS, and Willardson, JM. Acute hormone responses subsequent to agonist-antagonist paired set vs. traditional straight set resistance training. J Strength Cond Res 34(6): 1591-1599, 2020-The purpose of this study was to compare acute hormone responses and rating of perceived exertion (OMNI-Res) subsequent to the agonist-antagonist paired set (PS) vs. the traditional straight set (TS) resistance training method. Twelve recreationally trained men (25.7 ± 4.7 years, 173 ± 6.3 cm and 71.5 ± 6.6 kg) participated in the current study. After 10 repetition maximum (RM) load determination, each subject performed the following 2 experimental sessions in random order: TS session-3 sets of 10 repetitions at 85% of 10RM for the machine seated row and barbell bench press with 2-minute rest intervals between sets; and PS-3 sets of 10 repetitions with 85% of 10RM alternating machine seated row and barbell bench press for the total of 6 PSs with 2-minute rest intervals between sets. Total testosterone (TT), free testosterone (FT), cortisol, TT/cortisol ratio, growth hormone (GH), and blood lactate concentrations were measured before workout and immediately after workout and 15 and 30 minutes after workout. The OMNI-RES was recorded at the end of each set for both exercises within each session. Under the TS session, TT significantly increased immediately post-workout vs. the pre-workout time point. For the PS session, TT significantly decreased at 30-minute post-workout vs. the immediate post-workout time point, whereas, FT significantly increased immediately post-workout and 15-minute post-workout vs. the pre-workout time point. For the TS session, GH significantly increased immediately post-workout, and at the 15- and 30-minute post-workout time points vs. the pre-workout time point, respectively. For the PS session, GH was significantly increased immediately post-workout vs. the pre-workout time point. Blood lactate significantly increased at all post-workout time points vs. the pre-workout time point under both sessions. The cortisol and TT/cortisol ratio showed no differences between sessions. In conclusion, from an acute standpoint, the TS approach showed a tendency to cause greater disruption in hormone levels, despite the lack of significant differences vs. the PS approach at all time points. However, both strategies may promote similar acute hormone responses.

Neuromuscular responses for resistance training sessions adopting traditional, superset, paired set and circuit methods.

BACKGROUND: A challenging aspect of research in sports science is designing and conducting studies that simulate actual workout scenarios, especially with application to resistance training (RT). Therefore, the purpose of this study was to compare the effects of RT sessions performed in differing workout formats on myoelectric activity, strength performance, and metabolic markers (creatine kinase, lactate dehydrogenase, blood lactate) over 24, 48 and 72 hours post-workout. METHODS: Twenty-two trained men (25.2±4.1 years, 182.1±12.3 cm and 91.2±5.9 kg) performed the following four training protocols with 10-repetition maximum loads in random order: 1) traditional set (TS): three sets were performed in succession for the barbell bench press (BP), lat pulldown (LPD), 45° incline bench press (BP45), seated close-grip row (SCR), triceps extension (TE) and biceps curl (BC) on a pulley; 2) paired set (PS): three paired sets were performed as follows: BP-LPD, BP45-SCR, and TC-B; 3) super-set (SS): similar to the PS protocol, but without rest between paired exercises; 4) circuit training (CT): one set of each exercise was performed sequentially three times. RESULTS: The results showed greater total volume under the SS (8063.2±2270.5 kg) protocol versus the TS (7356.8±2279.7 kg). Total work (repetitions) was also significantly greater for the SS and CT protocols versus the TS (P<0.05). CONCLUSIONS: Therefore, the practitioners should consider utilizing the SS method during time-constrained periods with the goal to achieve greater training volume in time-efficient manner versus the TS, PS and CT methods.

Immunomodulation From Moderate Exercise Promotes Control of Experimental Cutaneous Leishmaniasis.

Physical exercise has been described as an important tool in the prevention and treatment of numerous diseases as it promotes a range of responses and adaptations in several biological systems, including the immune system. Studies on the effect of exercise on the immune system could play a critical role in improving public health. Current literature suggests that moderate intensity exercise can modulate the Th1/Th2 dichotomy directing the immune system to a Th1 cellular immune response, which favors the resolution of infections caused by intracellular microorganisms. Leishmaniasis is a group of diseases presenting a wide spectrum of clinical manifestations that range from self-limiting lesions to visceral injuries whose severity can lead to death. The etiological agents responsible for this group of diseases are protozoa of the genus Leishmania. Infections by the parasite Leishmania major in mice (Balb/c) provide a prototype model for the polarization of CD4+ T cell responses of both Th1 (resistance) or Th2 (susceptibility), which determines the progression of infections. The aim of this study was to evaluate the effect of exercise on the development of L. major experimental infections by scanning the pattern of immune response caused by exercise. Groups of Balb/c mice infected with L. major were divided into groups that preformed a physical exercise of swimming three times a week or were sedentary along with treatment or not with the reference drug, meglumine antimoniate. Animals in groups submitted to physical exercise did not appear to develop lesions and presented a significantly lower parasite load independent of drug treatment. They also showed a positive delayed hypersensitivity response to a specific Leishmania antigen compared to control animals. The IFN-γ/IL-4 and IFN-γ/IL10 ratios in trained animals were clearly tilted to a Th1 response in lymph node cells. These data suggest that moderate intensity exercise is able to modulate the Th1 response that provides a protective effect against the development of leishmanial lesions.

The synergism of high-intensity intermittent exercise and every-other-day intermittent fasting regimen on energy metabolism adaptations includes hexokinase activity and mitochondrial efficiency.

Visceral lipid accumulation, organ hypertrophy and a reduction in skeletal muscle strength are all signs associated with the severity of obesity-related disease. Intermittent fasting (IF) and high-intensity intermittent exercise (HIIE) are natural strategies that, individually, can prevent and help treat obesity along with metabolic syndrome and its associated diseases. However, the combinatorial effect of IF and HIIE on energetic metabolism is currently not well understood. We hypothesized that their combination could have a potential for more than strictly additive benefits. Here, we show that two months of every-other-day intermittent fasting regimen combined with a high-intensity intermittent exercise protocol (IF/HIIE) produced a synergistic effect, enhancing physical endurance (vs. control, HIIE and IF) and optimizing metabolic pathways of energy production in male Wistar rats. The IF/HIIE group presented enhanced glucose tolerance (vs. control, HIIE and IF), lower levels of plasma insulin (vs. control and HIIE), and a global activation of low Km hexokinases in liver (vs. control, HIIE and IF), heart (vs. control and HIIE) and skeletal muscle (vs. control, HIIE and IF). The IF/HIIE synergism, rather than a simply additive effect, is evidenced by increase in muscle mass and cross-section area, activation of the FoF1 ATP synthase, and the gain of characteristics suggestive of augmented mitochondrial mass and efficiency observed in this group. Finally, important reductions in plasma oxidative stress markers were present preferentially in IF/HIIE group. These findings provide new insights for the implementation of non-pharmaceutical strategies to prevent/treat metabolic syndrome and associated diseases.

Evaluation of redox profiles in exogenous subclinical hyperthyroidism at two different levels of TSH suppression.

OBJECTIVE: Evaluate the relationship between exogenous subclinical hyperthyroidism and oxidative stress through the analysis of the redox profile of patients with subclinical hyperthyroidism exogenous (SCH) grade I (TSH = 0.1 to 0.4 IU/mL) and grade II (TSH < 0.1 IU/mL). SUBJECTS AND METHODS: We analyzed 46 patients with SCH due to the use of TSH suppressive therapy with LT4 after total thyroidectomy along with 6 control euthyroid individuals (3M and 3W). Patients were divided into two groups, G1 with TSH ≥ 0.1-0.4 IU/mL (n = 25; and 7M 14W) and G2 with TSH < 0.1 IU/mL (n = 25; and 4M 21W). Venous blood samples were collected to measure the levels of markers for oxidative damage (TBARS, FOX and protein carbonylation), muscle and liver damage (CK, AST, ALT, GGT) and antioxidants (GSH, GSSG and catalase). RESULTS: Individuals in G2 showed a GSH/GSSG ratio ~ 30% greater than those in G1 (p = 0.004) and a catalase activity that was 4 times higher (p = 0.005). For lipid peroxidation, the levels measured in G2 were higher than both control and G1 (p = 0.05). No differences were observed for both protein carbonyl markers. G1 and G2 presented with greater indications of cell injury markers than the control group. CONCLUSION: TSH suppression therapy with LT4 that results in subclinical hyperthyroidism can cause a redox imbalance. The greater antioxidant capacity observed in the more suppressed group was not sufficient to avoid lipid peroxidation and cellular damage.

Evaluation of redox profiles in exogenous subclinical hyperthyroidism at two different levels of TSH suppression

ABSTRACT Objective: Evaluate the relationship between exogenous subclinical hyperthyroidism and oxidative stress through the analysis of the redox profile of patients with subclinical hyperthyroidism exogenous (SCH) grade I (TSH = 0.1 to 0.4 IU/mL) and grade II (TSH < 0.1 IU/mL). Subjects and methods: We analyzed 46 patients with SCH due to the use of TSH suppressive therapy with LT4 after total thyroidectomy along with 6 control euthyroid individuals (3M and 3W). Patients were divided into two groups, G1 with TSH ≥ 0.1-0.4 IU/mL (n = 25; and 7M 14W) and G2 with TSH < 0.1 IU/mL (n = 25; and 4M 21W). Venous blood samples were collected to measure the levels of markers for oxidative damage (TBARS, FOX and protein carbonylation), muscle and liver damage (CK, AST, ALT, GGT) and antioxidants (GSH, GSSG and catalase). Results: Individuals in G2 showed a GSH/GSSG ratio ~ 30% greater than those in G1 (p = 0.004) and a catalase activity that was 4 times higher (p = 0.005). For lipid peroxidation, the levels measured in G2 were higher than both control and G1 (p = 0.05). No differences were observed for both protein carbonyl markers. G1 and G2 presented with greater indications of cell injury markers than the control group. Conclusion: TSH suppression therapy with LT4 that results in subclinical hyperthyroidism can cause a redox imbalance. The greater antioxidant capacity observed in the more suppressed group was not sufficient to avoid lipid peroxidation and cellular damage.

Does a resistance exercise session with continuous or intermittent blood flow restriction promote muscle damage and increase oxidative stress?

The aim of this study was to compare the effect of low-load resistance exercise (LLRE) with continuous and intermittent blood flow restriction (BFR) on the creatine kinase (CK), lactate dehydrogenase (LDH), protein carbonyl (PC), thiobarbituric acid-reactive substance (TBARS) and uric acid (UA) levels in military men. The study included 10 recreationally trained men aged 19 ± 0.82 years who underwent the following experimental protocols in random order on separate days (72-96 h): 4 LLRE sessions at a 20% 1RM (one-repetition maximum [1RM]) with continuous BFR (LLRE + CBFR); 4 LLRE sessions at 20% 1RM with intermittent BFR (LLRE + IBFR) and 4 high-intensity resistance exercise (HIRE) sessions at 80% 1RM. The CK and LDH (markers of muscle damage) levels were measured before exercise (BE), 24 h post-exercise and 48 h post-exercise, and the PC, TBARS and UA (markers of oxidative stress) levels were measured BE and immediately after each exercise session. There was a significant increase in CK in the HIRE 24 post-exercise samples compared with the LLRE + CBFR and LLRE + IBFR (P = 0.035, P = 0.036, respectively), as well as between HIRE 48 post-exercise and LLRE + CBFR (P = 0.049). Additionally, there was a significant increase in CK in the LLRE + CBFR samples BE and immediately after each exercise (Δ = 21.9%) and in the HIRE samples BE and immediately after each exercise, BE and 24 post-exercise, and BE and 48 post-exercise (Δ values of 35%, 177.6%, and 177.6%, respectively). However, there were no significant changes in LDH, PC, TBARS, and UA between the protocols (P > 0.05). Therefore, a physical exercise session with continuous or intermittent BFR did not promote muscle damage; moreover, neither protocol seemed to affect the oxidative stress markers.

The influence of exercise order on strength performance in post menopause women / A influência da ordem dos exercícios sobre o desempenho da força muscular em mulheres na pós-menopausa

OBJECTIVE: Verify the influence of different exercise orders on the performance of the number of maximal repetitions in older women. METHODS: Twelve older women (65.7 ± 5.6 years, 66.9 ± 9.5 kg, 1.56 ± 0.67 m, 27.4 ± 3.6 kg/m2) underwent four nonconsecutive visits and two different orders of Resistance Training. At the first visit, the volunteers were submitted to anamnesis, anthropometric evaluation and a 10RM test. On the second visit, a re-test of 10RM was performed. On the third and fourth visits, the volunteers performed two exercise sequences: sequence A: bench press, latissimus pulldown close grip, biceps curl, triceps extension; for sequence B the order was inverted. Performance was measured by the number of repetitions in each exercise. To determine differences in performance for sequence A vs. sequence B, repeated measures were performed by two-way ANOVA followed by the Tuckey post-hoc test. RESULTS: The number of repetitions of each exercise varied significantly for the bench press, biceps curl and triceps extension between the exercise sequences. CONCLUSIONS: The order of the exercises performed in a resistance training session can affect the performance in the number of repetitions in older women.

OBJETIVO: Verificar a influência de diferentes sequências de exercícios no desempenho do número de repetições máximas em mulheres idosas. MÉTODOS: Doze mulheres idosas (65,7 ± 5,6 anos, 66,9 ± 9,5 kg, 1,56 ± 0,67 m; 27,4 ± 3,6 kg/m2) foram submetidas a diferentes sequências de exercícios no Treinamento Resistido. Na primeira visita, as voluntárias foram submetidas à anamnese, avaliação antropométrica e teste de 10 RM. Na segunda visita, foi feito um re-teste de 10RM. Na terceira e quarta visita, as voluntárias realizaram as duas sequências: SEQ A - supino horizontal, puxador alto fechado, rosca bíceps e rosca tríceps e, SEQ B - a ordem foi inversa. O desempenho foi medido pelo número de repetições em cada exercício. A fim de verificar as diferenças nos dados obtidos no desempenho em diferentes sequências e séries, foram realizadas medidas repetidas pela ANOVA two-way seguido do teste post-hoc de Tuckey. RESULTADOS: Os resultados demonstraram que o número de repetições de cada exercício variou significativamente entre as sequências nos exercícios de supino horizontal, rosca bíceps e rosca tríceps. CONCLUSÕES: A ordem dos exercícios realizada em uma sessão de treinamento resistido pode afetar o desempenho no número de repetições em mulheres idosas.

Impairing the function of MLCK, myosin Va or myosin Vb disrupts Rhinovirus B14 replication.

Together, the three human rhinovirus (RV) species are the most frequent cause of the common cold. Because of their high similarity with other viral species of the genus Enterovirus, within the large family Picornaviridae, studies on RV infectious activities often offer a less pathogenic model for more aggressive enteroviruses, e.g. poliovirus or EV71. Picornaviruses enter via receptor mediated endocytosis and replicate in the cytosol. Most of them depend on functional F-actin, Rab proteins, and probably motor proteins. To assess the latter, we evaluated the role of myosin light chain kinase (MLCK) and two myosin V isoforms (Va and Vb) in RV-B14 infection. We report that ML-9, a very specific MLCK inhibitor, dramatically reduced RV-B14 entry. We also demonstrate that RV-B14 infection in cells expressing dominant-negative forms of myosin Va and Vb was impaired after virus entry. Using immunofluorescent localization and immunoprecipitation, we show that myosin Va co-localized with RV-B14 exclusively after viral entry (15 min post infection) and that myosin Vb was present in the clusters of newly synthesized RNA in infected cells. These clusters, observed at 180 min post infection, are reminiscent of replication sites. Taken together, these results identify myosin light chain kinase, myosin Va and myosin Vb as new players in RV-B14 infection that participate directly or indirectly in different stages of the viral cycle.

Short-term consumption of Ilex paraguariensis extracts protects isolated hearts from ischemia/reperfusion injury and contradicts exercise-mediated cardioprotection.

Perfusion of hearts with extracts of Ilex paraguariensis (IP/mate) appears to reduce ischemia/reperfusion (I/R) injury. To determine if oral consumption of IP/mate can provide similar cardioprotection, short-term consumption was investigated alone or in association with exercise in rats. Animals were grouped into control (C), IP/mate consumption (M), exercise (E), and exercise with mate (E+M). M and E+M groups consumed IP/mate (1 g·kg-1 body weight in 1 mL water) by gavage. E and E+M groups swam 7× per week for 30 min carrying an additional 5% of body weight. After 1 week, hearts were tested ex vivo to measure left ventricle developed pressure (LVDP), systolic and end diastolic pressure (LVSP/LVEDP), maximum velocity of contraction and relaxation (dP/dt+ and dP/dt-) during I/R and infarction size. In addition, cardiac tissue was analyzed for oxidative stress by lipid peroxidation and protein carbonyl levels along with activity of catalase and superoxide dismutase (SOD). LVDP was higher in hearts from M and E groups as well as decreased infarction sizes than others. At the end of reperfusion, dP/dt+ was increased in E and M and dP/dt- was higher in M. LVSP was higher in M and E compared with C. Protein carbonyl and thiobarbituric acid reactive substances levels were higher in M while SOD activity was increased in E. No differences were observed in other activities. The results suggest that short-term consumption of IP/mate has protective effects on heart I/R injury similar to exercise, but the combination of these interventions appears to contradict the beneficial adaptations from exercise.

Oxidative stress and antioxidant biomarker responses after a moderate-intensity soccer training session.

The present study investigated the effects of a moderate-intensity soccer training session on the production of reactive oxygen species (ROS) and the antioxidant capacity in athletes along with the biomarkers creatine kinase and transaminases for lesions in muscle and liver cells. Twenty-two male soccer players participated in this study. Blood samples were collected 5 min before and after a moderate-intensity game simulation. The results showed a decrease in the concentration of reduced glutathione (GSH) from an elevation in the production of ROS that maintained the redox homeostasis. Although the session promoted an elevated energy demand, observed by an increase in lactate and glucose levels, damage to muscle and/or liver cells was only suggested by a significant elevation in the levels of alanine transaminase (ALT). Of the two biomarkers analysed, the results suggest that measurements of the ALT levels could be adopted as a method to monitor recovery in athletes.

Efeito do treinamento de força na potência muscular de membros inferiores de idosos coronariopatas / Effect of resistance training on muscular power of lower limbs of elderly with coronary artery disease

Introdução: A força e a potência muscular têm relação direta com a capacidade funcional de idosos. Objetivo: Verificar o efeito absoluto e relativo da potência muscular de membros inferiores em idosos portadores de doença arterial coronariana. Métodos: Dez homens sedentários participaram de 24 sessões de treinamento de força compostas por 2 séries de 6 a 8 repetições máximas e 1 minuto de intervalo. No início, os exercícios foram: meio agachamento, step, flexão plantar. E após: extensão e flexão dos joelhos, adução e abdução do quadril sentado. A potência muscular foi mensurada nos momentos: pré, após 12 e 24 sessões. Resultados: Após 24 sessões de treinamento de força foram encontrados aumentos na potência muscular absoluta (p< 0.0001) e relativa (p<0.0001; p<0.0001) em relação à condição pré-treinamento, respectivamente. Conclusão: Vinte e quatro sessões de treinamento de força parecem ser suficientes para aumentar a PM absoluta e relativa de idosos coronariopatas. (AU)

Introduction: Strength and muscle power have a direct relationship with functional capacity in elderly people. Objective: Verify absolute and relative gains in muscle power of lower limbs in elderly people with coronary artery disease. Methods: Ten untrained men subjects participated of 24 sessions of resistance training composed by 2 sets of 6 to 8 maximum repetitions and 1 minute rest interval. Initially, the exercises were: half squat, step up and plantar flexion. And after: leg extension, leg curl, seated hip adduction and seated hip abduction. The muscle power was measured at times: pre, post 12 and 24 sessions. Results: After 24 sessions of resistance training were found increases in absolute muscle power (p< 0.0001) and relative (p< 0.0001) regarding the condition pre-training, respectively. Conclusion: Twenty four sessions of resistance training appear to be sufficient to increase absolute and relative muscle power in elderly people with coronary artery disease. (AU)

Acute Effects of Resistance Exercise With Continuous and Intermittent Blood Flow Restriction on Hemodynamic Measurements and Perceived Exertion.

This study compared the acute effects of low-intensity resistance exercise (RE) sessions for the upper limb with continuous and intermittent blood flow restriction (BFR) and high-intensity RE with no BFR on lactate, heart rate, double product (DP; heart rate times systolic blood pressure), and perceived exertion (RPE). Ten recreationally trained men (1-5 years strength training; age mean = 19 ± 0.82 years) performed three experimental protocols in random order: (a) low-intensity RE at 20% one-repetition maximum (1RM) with intermittent BFR (LI + IBFR), (b) low-intensity RE at 20% 1RM with continuous BFR (LI + CBFR), and (c) high-intensity RE at 80% 1RM. The three RE protocols increased lactate and DP at the end of the session ( p < .05) and increased heart rate at the end of each exercise ( p < .05). However, greater local and general RPE was observed in the high-intensity protocol compared with LI + IBFR and LI + CBFR in the lat pull-down, triceps curl, and biceps curl exercises ( p < .05). A greater percentage change in DP and lactate was observed for continuous BFR compared with intermittent BFR; however, RPE was lower for intermittent BFR. In conclusion, intermittent BFR appears to be an excellent option for physical training because it did not differ significantly from continuous BFR in any variable and promoted a lower percentage change in DP and RPE.

Protein carbonyl levels correlate with performance in elite field hockey players.

Excess and incorrectly selected exercise can degrade athletic performance from an imbalance in redox homeostasis and oxidative stress, but well-planned training and nutrition can improve antioxidant capacity. The aim of the study was to investigate how nutrient intake could influence oxidative stress and cell lesion biomarkers after 5 days of training followed by a game. Blood was collected from 10 athletes at the start of training (basal), after training (pre-game), and postgame. Their acceleration capacity also was measured pre- and postgame. Blood analysis showed an increase in lactate concentration postgame (13%) and total antioxidant capacity increased both pre-game (13.1%) and postgame (12.7%), all in comparison with basal levels. An oxidative stress marker, protein carbonyl (PC), increased 3-fold over the course of the game, which correlated with a decreased acceleration (r = 0.749). For biomarkers of tissue damage, creatine kinase and aspartate transaminase (AST) increased postgame by 150% and 75%, respectively. The AST variation had a high negative correlation with energy and carbohydrate consumption and a moderate correlation with lipid and vitamin C intake. Protein intake had a positive but moderate correlation with reduced glutathione. The observed correlations suggest that nutritional monitoring can improve exercise physiological homeostasis and that PC serves as a good biomarker for oxidative stress and performance loss.

Exogenous ß-amyloid peptide interferes with GLUT4 localization in neurons.

Aging represents a major risk factor for numerous illnesses that are of increasing importance to society, including two of the most prevalent: diabetes and Alzheimer's disease. Studies have shown that diabetes is a risk factor for spontaneous Alzheimer's disease. While these studies suggest that diabetes can contribute to Alzheimer's disease, the implications of AD on diabetes are practically unexplored. The major mediator of the pathophysiological effects, the Aß42 peptide, has been shown to enter neurons and lead to an alteration of the intracellular distribution of the molecular motor myosin Vb. Myosin Vb functions in memory and learning by participating in the strengthening of the long-term potentiation (LTP) of synaptic transmissions. It has also been implicated in the translocation of the glucose transporter, GLUT4, to the plasma membrane in response to insulin, a process that is defective in diabetes. Here, the effect on GLUT4 upon entry of the Aß42 peptide into cultured chick retinal neurons was explored. The results suggest an alteration in distribution and a reduced level at the cell surface, as well as an increased colocalization with myosin Vb, which can partially explain the changes in glucose metabolism associated with AD. It is also shown that the presence of the Aß40 peptide inhibits the internalization of the Aß42 peptide in cultured cells. Together, the results provide additional targets for the development of therapeutics against the progression and effects of Alzheimer's disease.

Resistance Training in Type 2 Diabetic Patients Improves Uric Acid levels.

Resistance training (RT) can provide several benefits for individuals with Type 2 diabetes. The aim of this study was to investigate the effects of resistance training on the strength levels and uric acid (UA) concentration in individuals with Type 2 diabetes. The study included 68 patients (57.7±9.0 years) that participated in an organized program of RT for 12 weeks. The volunteers were divided into two groups: an experimental group (EG; n=34) that performed the resistance training program consisting of seven exercises executed in an alternating order based on segments; and a control group (CG; n=34) that maintained their normal daily life activities. Muscle strength and uric acid were measured both pre- and post-experiment. The results showed a significant increase in strength of the subjects in the EG for all exercises included in the study (p<0.001). Comparing the strength levels of the post-test, intergroup differences were found in supine sitting (p<0.001), leg extension (p<0.001), shoulder press (p<0.001), leg curl (p=0.001), seated row (p<0.001), leg press (p=0.001) and high pulley (p<0.001). The measured uric acid was significantly increased in both experimental and control groups (p<0.001 and p=0.001, respectively). The intergroup comparison showed a significant increase for the EG (p=0.024). We conclude that the training program was effective for strength gains despite an increase in uric acid in Type 2 diabetics.

Acute endocrine responses to different strength exercise order in men.

This study compared the effects of order of muscle groups' exercised (larger to smaller muscles vs. smaller to larger muscles) on the acute levels of total testosterone, free testosterone and cortisol during resistance training (RT) sessions. Healthy male participants (n=8; age: 28.8 ± 6.4 years; body mass: 87.0 ± 10.6 kg; body height: 181.0 ± 0.7 cm; BMI: 26.5 ± 4.1) were randomly separated into two experimental groups. The first group (LG-SM) performed an RT session (3 sets of 10 repetitions and a 2 min rest period) of the exercises in following order: bench press (BP), lat pulldown (LP), barbell shoulder press (BSP), triceps pushdown (TP) and barbell cut (BC). The second group (SM-LG) performed an RT session in following order: BC, TP, BSP, LA, BP. Blood was collected at the end of the last repetition of each session. Control samples of blood were taken after 30 min of rest. Significant differences were observed in the concentrations of total testosterone (p < 0.05), free testosterone (p < 0.0001) and cortisol (p < 0.0001) after both RT sessions in comparison to rest. However, when comparing LG-SM and SM-LG, no significant differences were found. The results suggest that, while RT sessions induce an acute change in the levels of testosterone and cortisol, this response is independent of the order of exercising muscle groups.

Biomarkers of oxidative stress and tissue damage released by muscle and liver after a single bout of swimming exercise.

Both acute exercise and excessive training can cause oxidative stress. The resulting increase in free radicals and the inadequate response from antioxidant systems can lead to a framework of cellular damage. An association between affected tissue and the biomarkers of oxidative stress that appear in plasma has not been clearly established. The aim of this study was to evaluate the source of oxidative stress biomarkers found in the plasma of untrained rats after a single bout of swimming exercise at 2 different intensities: low intensity (SBLIE) or high intensity (SBHIE). Immediately after the exercise, aspartate transaminase (AST), alanine transaminase (ALT), γ-glutamyltransferase (GGT), and lactate dehydrogenase (LDH) were measured in plasma to characterize cell damage. Oxidative stress was assessed using protein carbonylation (PC), total antioxidant capacity (TAC), and thiobarbituric acid reactive substances (TBARS) quantified by malondialdehyde concentration. SBHIE raised levels of plasma AST (93%) and ALT (17%), and both exercise regimens produced an increase in GGT (7%) and LDH (∼55%). Plasma levels of PC and TBARS were greater in the SBHIE group; there were no changes in TAC. SBLIE caused only a modest increase in TBARS. In muscle, there were no changes in TAC, PC, or TBARS, regardless of exercise intensity, In the liver, TAC and TBARS increased significantly in both the SBLIE and SBHIE groups. This indicates that the oxidative stress biomarkers measured in the plasma immediately after a single bout of swimming exercise were generated primarily in the liver, not in muscle.

Interactions between Leishmania braziliensis and Macrophages Are Dependent on the Cytoskeleton and Myosin Va.

Leishmaniasis is a neglected tropical disease with no effective vaccines. Actin, microtubules and the actin-based molecular motor myosin Va were investigated for their involvement in Leishmania braziliensis macrophage interactions. Results showed a decrease in the association index when macrophages were without F-actin or microtubules regardless of the activation state of the macrophage. In the absence of F-actin, the production of NO in non-activated cells increased, while in activated cells, the production of NO was reduced independent of parasites. The opposite effect of an increased NO production was observed in the absence of microtubules. In activated cells, the loss of cytoskeletal components inhibited the release of IL-10 during parasite interactions. The production of IL-10 also decreased in the absence of actin or microtubules in non-activated macrophages. Only the disruption of actin altered the production of TNF-α in activated macrophages. The expression of myosin Va tail resulted in an acute decrease in the association index between transfected macrophages and L. braziliensis promastigotes. These data reveal the importance of F-actin, microtubules, and myosin-Va suggesting that modulation of the cytoskeleton may be a mechanism used by L. braziliensis to overcome the natural responses of macrophages to establish infections.