Exhaustive exercise in a hot environment can impair performance. Higher epinephrine plasma levels occur during exercise in heat, indicating greater sympathetic activity. This study examined the ...influence of exercise in the heat on stress levels. Nine young healthy men performed a maximal progressive test on a cycle ergometer at two different environmental conditions: hot (40°C) and normal (22°C), both between 40% and 50% relative humidity. Venous blood and saliva samples were collected pre-test and post-test. Before exercise there were no significant changes in salivary biomarkers (salivary IgA: p = 0.12; α-amylase: p = 0.66; cortisol: p = 0.95; nitric oxide: p = 0.13; total proteins: p = 0.07) or blood lactate (p = 0.14) between the two thermal environments. Following exercise, there were significant increases in all variables (salivary IgA 22°C: p = 0.04, 40°C: p = 0.0002; α-amylase 22°C: p = 0.0002, 40°C: p = 0.0002; cortisol 22°C: p = 0.02, 40°C: p = 0.0002; nitric oxide 22°C: p = 0.0005, 40°C: p = 0.0003, total proteins 22°C: p<0.0001, 40°C: p<0.0001 and; blood lactate 22°C: p<0.0001, 40°C: p<0.0001) both at 22°C and 40°C. There was no significant adjustment regarding IgA levels between the two thermal environments (p = 0.74), however the levels of α-amylase (p = 0.02), cortisol (p<0.0001), nitric oxide (p = 0.02) and total proteins (p = 0.01) in saliva were higher in the hotter conditions. Blood lactate was lower under the hot environment (p = 0.01). In conclusion, enduring hot temperature intensified stressful responses elicited by exercise. This study advocates that hot temperature deteriorates exercise performance under exhaustive stress and effort conditions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study aimed to evaluate the effect of head pre‐cooling on the 5‐km time‐trial performance of amateur runners in the heat. In a counterbalanced design, 15 male amateur runners (22.6 ± 3.5 y; VO2 ...max in heat 42.3 ± 4.4 mLO2/kg/min) completed two 5‐km time trials performed in the heat (35°C, 50% relative humidity). In one trial (HCOOL), participants underwent 20 min of head cooling in a temperate environment (23°C, 70% relative humidity) prior to exercise. In another trial (CON), exercise was preceded by 20 min of rest under the same temperature conditions. Exercise time was shorter in HCOOL (25 min and 36 s ± 3 min) compared to CON (27 ± 3 min; p = 0.02). Rectal temperature was reduced during the pre‐exercise intervention in HCOOL (p < 0.001), but not in CON (p = 0.55). Relative changes in rectal temperature and mean head temperature were lower throughout HCOOL when compared with CON condition (p = 0.005 and p = 0.022, respectively). Mean skin temperature, heart rate, and rating of perceived exertion did not differ between HCOOL and CON conditions throughout exercise (p = 0.20, p = 0.52 and 0.31, respectively). Thermal comfort was lower in HCOOL condition in pre‐exercise (p = 0.014) with no differences observed throughout exercise (p = 0.61). 5‐km running performance in a hot environment was improved after a 20‐min head cooling intervention, suggesting that this method may be practical as pre‐cooling strategy and easily administered to both professional and amateur runners alike.
In addition to autophagy, proteasomes are critical for regulating intracellular protein levels and removing misfolded proteins. The 20S proteasome (20SPT), the central catalytic unit, is sometimes ...flanked by regulatory units at one or both ends. Additionally, proteosomal activation has been associated with increased lifespan in many organisms. Our group previously reported that the gating (open/closed) of the free 20S proteasome is redox controlled, and that S-glutathionylation of two Cys residues (Cys76 and Cys221) in the α5 subunit promotes gate opening. The present study constructed site-directed mutants of these Cys residues, and evaluated the effects these mutations have on proteosome gate opening and yeast cell survival. Notably, the double mutation of both Cys residues (Cys76 and Cys221) rendered the cells nonviable, whereas the lifespan of the yeast carrying the single mutations (α5-C76S or α5-C221S) was attenuated when compared to the wild type counterpart. Furthermore, it was found that α5-C76S or α5-C221S 20SPT were more likely to be found with the gate in a closed conformation. In contrast, a random α5-subunit double mutation (S35P/C221S) promoted gate opening, increased chronological lifespan and provided resistance to oxidative stress. The 20SPT core particle purified from the long-lived strain degraded model proteins (e.g., α-synuclein) more efficiently than preparations obtained from the wild-type counterpart, and also displayed an increased chymotrypsin-like activity. Mass spectrometric analyses of the C76S, C221S, S35P/C221S, S35P and S35P/C76S mutants provided evidence that the highly conserved Cys76 residue of the α5-subunit is the key determinant for gate opening and cellular survival. The present study reveals a sophisticated regulatory mechanism that controls gate opening, which appears to be based on the interactions among multiple residues within the α5-subunit, and consequently impacts the lifespan of yeast.
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•α5-C76 and α5-C221 residues of the yeast 20S proteasome are redox modified.•The double mutation α5-C76S/C221S rendered unviable cells.•Single α5-C76S or C221S mutated-particles prevail in the closed conformation.•The random double mutant α5- S35P/C221S prevails in the open conformation.•20SPT gate conformation was associated to the chronological lifespan of yeast cells.
Abstract Aims: Movement specific warm-up is a widely accepted practice in the sports environment; however, little is known regarding the ideal intensity of its performance. To verify the effects of ...adding high-intensity sets to the warm-up on strength, muscular electrical activity, and body temperature in the bench press exercise. Methods: Twelve men (21±1.7 years, 23.9±3.5 kg.m2) were evaluated by a maximal repetition test (1-RM), after which the volunteers performed three procedures: Low-intensity warm-up (LIW), low-intensity warm-up with high-intensity sets (WHI), and no warm-up (CON). Next, they performed maximal isometric voluntary contractions (MIVC) of the chest press to assess the electromyographic activity of the pectoralis major, peak rate of force, development (RFDpeak), and maximum strength (Smax). The skin temperature was evaluated before starting the test. Results: No between-condition differences (p≤0.05) were found for Smax (CON = 320.3±83.8 N; LIW = 300.1±131.6 N, HIW = 327.0±113.9 N; p = 0.689), RFDpeak (CON = 4399±1776 Ns-1; LIW = 3476±1905 Ns-1; HIW = 4715±2184 Ns-1; p = 0.243), skin temperature (CON = 34.0±1.0 °C, LIW = 34.9±0.8 °C, HIW = 34.8±1.1 °C; p = 0.078) or myoelectric activity according to the root mean square index of sternocostal (p = 0.402) and clavicular (p = 0.535) heads, as well as the median frequency data of sternocostal (p = 0.169) and clavicular heads (p = 0.456). Conclusion: In conclusion, the proposed warm-up protocols were not able to modify strength, muscle electrical activity, or skin temperature in the bench press exercise.
The aim of this study was to verify the acute effects of a single bout of a 30-sec anaerobic power exercise session (Wingate Test) on heart rate (HR) and blood pressure (BP) responses. Ten sedentary ...subjects (one male and nine females) 22.6 + or - 3.8 yrs old, 60.7 + or - 9.8 kg, and 162 + or - 8 cm participated in the study. Heart rate, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were evaluated before and after an anaerobic exercise bout. Subjects remained seated for 5 min for HR and BP measurements at rest and, then, they performed the 30-sec Wingate Test with a 7.5% of body mass load. HR and BP were measured just after the test and at 30, 60, 90, and 120 min after the test during which all subjects remained seated. The results were analyzed by an ANOVA with repeated measures and Tukey post hoc test (P < 0.05). The post-exercise 120-min SBP of 95.0 + or - 12.5 mmHg was significantly lower than the resting value of 110.5 + or - 6.0 mmHg. The post-exercise 120-min DBP (64.0 + or - 5.2 mmHg) was not significantly lower than the pre-exercise value (71.5 + or - 9.4 mmHg), and the post-exercise 120-min HR (83 + or - 16 beatsmin-1) was significantly higher than the resting value of 71 + or - 10 beatsmin-1. We concluded that a single short power anaerobic exercise (such as the 30-sec Wingate Test) resulted in a post-exercise hypotension response that may contribute to a better control of blood pressure. Key Words: Hypertension, Blood pressure, Physical exercise
Recently, new serine integrases have been identified, increasing the possibility of scaling up genomic modulation tools. Here, we describe the use of unidirectional genetic switches to evaluate the ...functionality of six serine integrases in different eukaryotic systems: the HEK 293T cell lineage, bovine fibroblasts and plant protoplasts. Moreover, integrase activity was also tested in human cell types of therapeutic interest: peripheral blood mononuclear cells (PBMCs), neural stem cells (NSCs) and undifferentiated embryonic stem (ES) cells. The switches were composed of plasmids designed to flip two different genetic parts driven by serine integrases. Cell-based assays were evaluated by measurement of EGFP fluorescence and by molecular analysis of attL/attR sites formation after integrase functionality. Our results demonstrate that all the integrases were capable of inverting the targeted DNA sequences, exhibiting distinct performances based on the cell type or the switchable genetic sequence. These results should support the development of tunable genetic circuits to regulate eukaryotic gene expression.
Osteoporotic vertebral fractures result in increased kyphosis angle, an alteration that may lead to disturbance in physical capacity.
We sought to evaluate physical capacity and disability in a group ...of osteoporotic patients.
Fifteen women with osteoporosis and vertebral fractures (G1), 20 women with osteoporosis without vertebral fractures (G2), and 20 control women (G3) were selected. The variables of physical capacity were measured using a treadmill. The patients spent 4 min standing quietly, 4 min walking at 3 km/h, and 10 min walking at 4 km/h. The SF-36 questionnaire was also applied.
The results showed that women with osteoporosis and vertebral fractures (G1) had increased kyphosis angle (median 60 degrees ), while the angle was 43.5 degrees for G2 and 37 degrees for G3. Oxygen consumption (VO(2) (kg)), METS (metabolic equivalent), and energy expenditure (kcal/h) during the standing period were higher in G1 than in G2 (G1 vs G2, p=0.016, p=0.017, and p=0.012, respectively), whereas no difference in these parameters was observed between groups during the walking period. The energy expenditure during walking at 3 km/h and at 4 km/h showed a correlation with thoracic kyphosis in G1 (p=0.01 and p=0.017, respectively). No difference in SF-36 scores was observed between the three groups.
Energy expenditure showed a correlation with the angle of thoracic kyphosis. Patients with or without osteoporosis showed the same energy expenditure during the walking period. The SF-36 score was similar for the three groups.
A total of 209 events of quasi-monochromatic atmospheric gravity waves (QMGWs) were acquired over 5 years of gravity waves (GWs) observation in southern Brazil. The observations were made by ...measuring the OH (hydroxyl radical) emission using an all-sky imager hosted by the Southern Space Observatory (SSO) coordinated by the National Institute for Space Research at São Martinho da Serra (RS) (29.44° S, 53.82° W). Using a two-dimensional fast-Fourier-Transform-based spectral analysis, it has been shown that the QMGWs have horizontal wavelengths of 10–55 km, periods of 5–74 min, and phase speeds up to 100 m s−1. The waves exhibited clear seasonal dependence on the propagation direction with anisotropic behavior, propagating mainly toward the southeast during the summer and autumn seasons and mainly toward the northwest during the winter. On the other hand, the propagation directions in the spring season exhibited a wide range from northwest to south. A complementary backward ray-tracing result revealed that the significant factors contributing to the propagation direction of the QMGWs are their source locations and the dynamics of the background winds per season. Three case studies in winter were selected to investigate further the propagation dynamics of the waves and determine their possible source location. We found that the jet stream associated with the cold front and their interaction generated these three GW events.
•Surveillance of deaths in NHPs is a key point for the prevention of YF in humans.•Determination of hepatic pathological features are crucial for screening YF in NHPs.•YF-associated hepatic injuries ...may vary between South American NHPs genera.•Humans and NHPs show marked differences in the set of YF-associated hepatic lesions.
The early detection and diagnosis of deaths in free-ranging non-human primates (NHPs) are key points for the surveillance of Yellow Fever (YF) in Brazil. The histopathological identification of infectious diseases remains very useful and reliable in the screening and detection of emerging zoonotic diseases such as YF. We surveyed data records and liver slides stained with hematoxylin and eosin from the Epizootics Surveillance Network to control YF, Ministry of Health of Brazil, to evaluate histopathological hallmarks for the diagnosis of the YF virus infection. We selected natural fatal cases in NHPs from the genera Alouatta spp., Callithrix spp., and Sapajus spp. with a positive immunohistochemical assay for YF in liver samples. Our findings showed the full-spectrum YF-associated hepatic lesions in all NHPs, but some histopathological findings differed in the distribution and intensity between the three genera. In our study, South American NHPs showed significant differences in the YF-associated hepatic histopathological features compared to fatal cases reported in humans.
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