Time-course effects of aerobic physical training in the prevention of cigarette smoke-induced COPD
A previous study by our group showed that regular exercise training (ET) attenuated pulmonary injury in an experimental model of chronic exposure to cigarette smoke (CS) in mice, but the time-course effects of the mechanisms involved in this protection remain poorly understood. We evaluated the temporal effects of regular ET in an experimental model of chronic CS exposure. Male C57BL/6 mice were divided into four groups: Control (sedentary + air), Exercise (aerobic training + air), Smoke (sedentary + smoke), and Smoke + Exercise (aerobic training + smoke). Mice were exposed to CS and ET for 4, 8, or 12 wk. Exercise protect...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Toledo-Arruda, A. C., Vieira, R. P., Guarnier, F. A., Suehiro, C. L., Caleman-Neto, A., Olivo, C. R., Arantes, P. M. M., Almeida, F. M., Lopes, F. D. T. Q. S., Ramos, E. M. C., Cecchini, R., Lin, C. J., Martins, M. A. Tags: RESEARCH ARTICLE Source Type: research
Adaptations of motoneuron properties after weight-lifting training in rats
Resistance training, with repeated short-term and high-intensity exercises, is responsible for an increase in muscle mass and force. The aim of this study was to determine whether such training induces adaptations in the electrophysiological properties of motoneurons innervating the trained muscles and to relate these adaptive changes to previous observations made on motor unit contractile properties. The study was performed on adult male Wistar rats. Animals from the training group were subjected to a 5-wk voluntary progressive weight-lifting program, whereas control rats were restricted to standard cage activity. Intrace...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Krutki, P., Mrowczynski, W., Baczyk, M., Łochynski, D., Celichowski, J. Tags: RESEARCH ARTICLE Source Type: research
Reduced collagen accumulation and augmented MMP-2 activity in left ventricle of old rats submitted to high-intensity resistance training
In conclusion, RT attenuated age-associated collagen accumulation, concomitant to the increase in MMP-2 activity and decreased expression of COL-I, TGF-β1, and TIMP-1 in LV, illustrating a cardioprotective effect of RT on ventricular structure and function.
NEW & NOTEWORTHY We demonstrated the beneficial resistance-training effect against age-related left ventricle collagen accumulation in the left ventricle, which was associated with decreased type I collagen (COL-I), transforming growth factor-β1 (TGF-β1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) gene expression and matrix metalloproteinas...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Guzzoni, V., Marqueti, R. d. C., Durigan, J. L. Q., Faustino de Carvalho, H., Lino, R. L. B., Mekaro, M. S., Costa Santos, T. O., Mecawi, A. S., Rodrigues, J. A., Hord, J. M., Lawler, J. M., Davel, A. P., Selistre-de-Araujo, H. S. Tags: RESEARCH ARTICLE Source Type: research
CORP: The assessment of total hemoglobin mass by carbon monoxide rebreathing
In this Cores of Reproducibility in Physiology (CORP) article, we present the theory and practical aspects of the carbon monoxide (CO) rebreathing method for the determination of total hemoglobin mass in humans. With CO rebreathing, a small quantity of CO is diluted in O2 and rebreathed for a specified time period, during which most of the CO is absorbed and bound to circulating hemoglobin. The dilution principle then allows calculation of the total number of circulating hemoglobin molecules based on the number of absorbed CO molecules and the resulting changes in the fraction of carboxyhemoglobin in blood. Total hemoglobi...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Siebenmann, C., Keiser, S., Robach, P., Lundby, C. Tags: REVIEW Source Type: research
Sodium nitrate ingestion increases skeletal muscle nitrate content in humans
In conclusion, basal NO3– concentrations are substantially higher in human skeletal muscle tissue compared with plasma. Ingestion of a bolus of dietary NO3– increases both plasma and muscle NO3– contents in humans.
NEW & NOTEWORTHY Literature of the pharmacokinetics following dietary nitrate ingestion is usually limited to the changes observed in plasma nitrate and nitrite concentrations. The present investigation assessed the skeletal muscle nitrate content in humans during the postabsorptive state, as well as following dietary nitrate ingestion. We show that basal nitrate content is higher in skelet...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Nyakayiru, J., Kouw, I. W. K., Cermak, N. M., Senden, J. M., van Loon, L. J. C., Verdijk, L. B. Tags: RESEARCH ARTICLE Source Type: research
CORP: Improving the status quo for measuring whole body sweat losses
The measurement of whole body sweat losses (WBSL) is important to the study of body heat balance, body water balance, establishing guidelines for water and electrolyte consumption, and the study of metabolism and health. In principal, WBSL is measured by an acute change in body mass (BM) in response to a thermoregulatory sweating stimulus. In this Cores of Reproducibility in Physiology (CORP) review, we revisit several basic, but rarely discussed, assumptions important to WBSL research, including the common equivalences: mass = weight = water = sweat. Sources of large potential measurement errors are also discussed, as are...
Source: Journal of Applied Physiology - September 25, 2017 Category: Physiology Authors: Cheuvront, S. N., Kenefick, R. W. Tags: REVIEW Source Type: research
Leg blood flow is impaired during small muscle mass exercise in patients with COPD
This study demonstrates that chronic obstructive pulmonary disease (COPD) is associated with a reduced blood flow to skeletal muscle during small muscle mass exercise. In contrast to healthy individuals, interstitial prostacyclin levels did not increase during exercise and plasma endothelin-1 levels were higher in the patients with COPD. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Iepsen, U. W., Munch, G. W., Rugbjerg, M., Ryrso, C. K., Secher, N. H., Hellsten, Y., Lange, P., Pedersen, B. K., Thaning, P., Mortensen, S. P. Tags: RESEARCH ARTICLE Source Type: research
Potential involvement of lactate and interleukin-6 in the appetite-regulatory hormonal response to an acute exercise bout
This study examines the involvement of two potential mechanisms (lactate and IL-6) that may explain the intensity-dependent effects of acute exercise on appetite-related parameters. Our findings support a clear intensity-dependent paradigm for appetite regulation following exercise, as highlighted by the change in acylated ghrelin and the suppression of appetite and energy intake after vigorous exercise (continuous and intermittent). Further, our findings extend previous work in animal/cell models by providing evidence for the potential role of lactate and IL-6 in mediating changes in appetite-related parameters following ...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Islam, H., Townsend, L. K., McKie, G. L., Medeiros, P. J., Gurd, B. J., Hazell, T. J. Tags: RESEARCH ARTICLE Source Type: research
Timing of postexercise carbohydrate-protein supplementation: roles of gastrointestinal blood flow and mucosal cell damage on gastric emptying in humans
In conclusion, the CABF response after exercise seems to modulate the subsequent GE rate and SMABF response.
NEW & NOTEWORTHY A carbohydrate-protein drink was ingested at either 5 min (i.e., profoundly decreased celiac artery blood flow; CABF) or 30 min (i.e., already recovered CABF) postexercise. In the 5-min postexercise trial, the gastric emptying (GE) rate and superior mesenteric artery blood flow (SMABF) response were slower than those in the 30-min postexercise trial. The GE rate and SMABF response may be altered depending on the postexercise CABF response. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Kashima, H., Harada, N., Miyamoto, K., Fujimoto, M., Fujita, C., Endo, M. Y., Kobayashi, T., Miura, A., Fukuba, Y. Tags: RESEARCH ARTICLE Source Type: research
Dietary nitrate restores compensatory vasodilation and exercise capacity in response to a compromise in oxygen delivery in the noncompensator phenotype
In conclusion, dietary nitrate supplementation during a perfusion pressure challenge is an effective means of restoring exercise capacity and enabling compensatory vasodilation.
NEW & NOTEWORTHY Previously, we identified young, healthy persons who suffer compromised exercise tolerance when exercising muscle perfusion pressure is reduced as a result of a lack of compensatory vasodilation. The ability of nitrate supplementation to restore compensatory vasodilation in such noncompensators is unknown. We demonstrated that beetroot juice supplementation led to compensatory vasodilation and restored perfusion and exercise ca...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Bentley, R. F., Walsh, J. J., Drouin, P. J., Velickovic, A., Kitner, S. J., Fenuta, A. M., Tschakovsky, M. E. Tags: RESEARCH ARTICLE Source Type: research
Dynamic hyperinflation and exercise limitations in obese asthmatic women
This study shows that dynamic hyperinflation is a common condition in obese asthmatics; they have reduced fitness for activities of daily living compared to nonobese asthmatics. However, peripheral limitation was the main factor associated with reduced capacity of exercise in these patients.
NEW & NOTEWORTHY This is the first study to investigate the occurrence of dynamic hyperinflation (DH) in obese asthmatics. Our results demonstrate that obese asthmatics present a higher frequency and intensity of DH than nonobese asthmatics. We also show that physical deconditioning in this population is linearly associated with ca...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Ferreira, P. G., Freitas, P. D., Silva, A. G., Porras, D. C., Stelmach, R., Cukier, A., Fernandes, F. L. A., Martins, M. A., Carvalho, C. R. F. Tags: RESEARCH ARTICLE Source Type: research
Novel analysis of 4DCT imaging quantifies progressive increases in anatomic dead space during mechanical ventilation in mice
Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV. Detailed measurements of airway vo...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Kim, E. H., Preissner, M., Carnibella, R. P., Samarage, C. R., Bennett, E., Diniz, M. A., Fouras, A., Zosky, G. R., Jones, H. D. Tags: RESEARCH ARTICLE Source Type: research
Exercise training improves cardiac autonomic control, cardiac function, and arrhythmogenesis in rats with preserved-ejection fraction heart failure
Chronic heart failure is characterized by autonomic imbalance, cardiac dysfunction, and arrhythmogenesis. It has been shown that exercise training (ExT) improves central nervous system oxidative stress, autonomic control, and cardiac function in heart failure with reduced ejection fraction; however, to date no comprehensive studies have addressed the effects of ExT, if any, on oxidative stress in brain stem cardiovascular areas, cardiac autonomic balance, arrhythmogenesis, and cardiac function in heart failure with preserved ejection fraction (HFpEF). We hypothesize that ExT reduces brain stem oxidative stress, improves ca...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Andrade, D. C., Arce-Alvarez, A., Toledo, C., Diaz, H. S., Lucero, C., Schultz, H. D., Marcus, N. J., Del Rio, R. Tags: RESEARCH ARTICLE Source Type: research
Random squat/stand maneuvers: a novel approach for assessment of dynamic cerebral autoregulation?
In conclusion, RFSSMs are an effective and noninvasive method of assessing dCA. There is no difference in the ARI estimates in comparison with FFSSMs. Although FFSSMs have been well tolerated previously, RFSSMs are preferred by healthy subjects and thus may be better tolerated by a patient population in a clinical setting.
NEW & NOTEWORTHY RFSSMs provided comparable estimates of autoregulatory indices to FFSSMs. Instead of point estimates at the driven frequency, RFSSMs generate a broader power spectrum of changes in arterial blood pressure and cerebral blood flow velocity, allowing direct comparison with spontaneous f...
Source: Journal of Applied Physiology - September 14, 2017 Category: Physiology Authors: Barnes, S. C., Ball, N., Panerai, R. B., Robinson, T. G., Haunton, V. J. Tags: INNOVATIVE METHODOLOGY Source Type: research
Pretreatment with indomethacin results in increased heat stroke severity during recovery in a rodent model of heat stroke
It has been suggested that medications can increase heat stroke (HS) susceptibility/severity. We investigated whether the nonsteroidal anti-inflammatory drug (NSAID) indomethacin (INDO) increases HS severity in a rodent model. Core temperature (Tc) of male, C57BL/6J mice (n = 45) was monitored continuously, and mice were given a dose of INDO [low dose (LO) 1 mg/kg or high dose (HI) 5 mg/kg in flavored treat] or vehicle (flavored treat) before heating. HS animals were heated to 42.4°C and euthanized at three time points for histological, molecular, and metabolic analysis: onset of HS [maximal core temperature (Tc,Max)],...
Source: Journal of Applied Physiology - September 6, 2017 Category: Physiology Authors: Audet, G. N., Dineen, S. M., Stewart, D. A., Plamper, M. L., Pathmasiri, W. W., McRitchie, S. L., Sumner, S. J., Leon, L. R. Tags: RESEARCH ARTICLE Source Type: research
