Physiology Research This is an OPML file. It can be used to export all the MedWorm RSS feeds on this topic into your personal RSS reader (usually you have to save this file to your own computer before clicking on an Import OPML command in your own feed reader to upload the file which will then import all the feeds) or it can be used by webmasters to integrate MedWorm feeds with their own website. This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.
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When worlds collide--elite sport, doping, and scientific research
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Wagner, P. D. Tags: EDITORIALS Source Type: research
Reconsideration of a Tour de France cyclist
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Coyle, E. F. Tags: EDITORIALS Source Type: research
Ethical considerations for experiments involving elite athletes and "doping"
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Schumacher, Y. O., Garvican, L. A., Pottgiesser, T., Martin, D. T., Ahlgrim, C., Gore, C. J. Tags: LETTERS TO THE EDITOR Source Type: research
Reply to Schumacher et al.
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Lundby, C., Robach, P. Tags: LETTERS TO THE EDITOR Source Type: research
Scientific research using elite athletes: WADA point of view
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Howman, D. Tags: LETTERS TO THE EDITOR Source Type: research
Phosphorylation of myocardial eNOS is altered in patients suffering from type 2 diabetes
The present study investigated whether endothelial nitric oxide synthase (eNOS) activation may be dysregulated in cardiac tissue of patients suffering from type 2 diabetes (T2D). We performed immunohistochemical measurements of translocated eNOS activation as well as eNOS phosphorylation at Ser1177, Thr495, Ser 635, Ser114, and of the protein kinase B (Akt) in isolated right atrial trabeculae of patients undergoing cardiac bypass or valve surgery with (n = 12, 68.1 ± 2.5 yr) and without T2D (n = 12, 64.7 ± 2.7 yr). In addition, we investigated oxidative (8-isoprostane) and nitrosative stress markers (nitrotyr...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Streit, U., Reuter, H., Bloch, W., Wahlers, T., Schwinger, R. H. G., Brixius, K. Tags: ARTICLES Source Type: research
Racial differences in the response of cardiorespiratory fitness to aerobic exercise training in Caucasian and African American postmenopausal women
African American (AA) women have an elevated risk of cardiovascular disease and have been reported to have lower cardiorespiratory fitness (CRF) compared with Caucasian American (CA) women. However, little data exist that evaluate racial differences in the change in CRF following aerobic exercise training. CA (n = 264) and AA (n = 122) postmenopausal women from the Dose-Response to Exercise in Women study were randomized to 4, 8, and 12 kcal·kg body wt–1·wk–13 (KKW) of aerobic training or the control group for 6 mo. CRF was evaluated using a cycle ergometer. A greater increase in relative CRF was ...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Swift, D. L., Johannsen, N. M., Lavie, C. J., Earnest, C. P., Johnson, W. D., Blair, S. N., Church, T. S., Newton, R. L. Tags: ARTICLES Source Type: research
Cerebrovascular reactivity is associated with maximal aerobic capacity in healthy older adults
Recently, several high-impact reviews suggest that regular aerobic exercise is beneficial for maintaining cognitive function in aging adults. Higher cerebral blood flow and/or cerebrovascular reactivity may explain the favorable effect of exercise on cognition. In addition, prostaglandin-mediated vasodilator responses may be influenced by regular exercise. Therefore, our purpose was to evaluate middle cerebral artery (MCA) vasodilator responses in healthy adults before and after cyclooxygenase inhibition. A total of 16 young (26 ± 6 yr; 8 males, 8 females) and 13 older (64 ± 6 yr; 7 males, 6 females) healthy ...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Barnes, J. N., Taylor, J. L., Kluck, B. N., Johnson, C. P., Joyner, M. J. Tags: ARTICLES Source Type: research
Inactivity-induced phrenic and hypoglossal motor facilitation are differentially expressed following intermittent vs. sustained neural apnea
Reduced respiratory neural activity elicits a rebound increase in phrenic and hypoglossal motor output known as inactivity-induced phrenic and hypoglossal motor facilitation (iPMF and iHMF, respectively). We hypothesized that, similar to other forms of respiratory plasticity, iPMF and iHMF are pattern sensitive. Central respiratory neural activity was reversibly reduced in ventilated rats by hyperventilating below the CO2 apneic threshold to create brief intermittent neural apneas (5, ~1.5 min each, separated by 5 min), a single brief massed neural apnea (7.5 min), or a single prolonged neural apnea (30 min). Upon restorat...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Baertsch, N. A., Baker-Herman, T. L. Tags: ARTICLES Source Type: research
Bubbles, microparticles, and neutrophil activation: changes with exercise level and breathing gas during open-water SCUBA diving
The study goal was to evaluate responses in humans following decompression from open-water SCUBA diving with the hypothesis that exertion underwater and use of a breathing mixture containing more oxygen and less nitrogen (enriched air nitrox) would alter annexin V-positive microparticle (MP) production and size changes and neutrophil activation, as well as their relationships to intravascular bubble formation. Twenty-four divers followed a uniform dive profile to 18 m of sea water breathing air or 22.5 m breathing 32% oxygen/68% nitrogen for 47 min, either swimming with moderately heavy exertion underwater or remaining sta...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Thom, S. R., Milovanova, T. N., Bogush, M., Yang, M., Bhopale, V. M., Pollock, N. W., Ljubkovic, M., Denoble, P., Madden, D., Lozo, M., Dujic, Z. Tags: ARTICLES Source Type: research
Active, passive, and motor imagery paradigms: component analysis to assess neurovascular coupling
The association between neural activity and cerebral blood flow (CBF) has been used to assess neurovascular coupling (NVC) in health and diseases states, but little attention has been given to the contribution of simultaneous changes in peripheral covariates. We used an innovative approach to assess the contributions of arterial blood pressure (BP), PaCO2, and the stimulus itself to changes in CBF velocities (CBFv) during active (MA), passive (MP), and motor imagery (MI) paradigms. Continuous recordings of CBFv, beat-to-beat BP, heart rate, and breath-by-breath end-tidal CO2 (EtCO2) were performed in 17 right-handed subjec...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Salinet, A. S. M., Robinson, T. G., Panerai, R. B. Tags: ARTICLES Source Type: research
Antibody and CD8+ T cell memory response to influenza A/PR/8/34 infection is reduced in treadmill-exercised mice, yet still protective
Moderate exercise may decrease the severity of influenza infection and reduce lung viral load. The possibility that an exercise-associated reduction in lung viral load early in infection could contribute to decreased serum antibody and reduced memory response were investigated. BALB/c mice exercised for 8 wk and were then infected with influenza A/PR/8/34 (intranasal route). Influenza-specific serum antibody was assessed for 6 mo post primary infection, at which time mice were infected again with influenza A/PR/8/34. After primary infection, exercise reduced morbidity/mortality, attenuated lung cytokines, and decreased ser...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Warren, K., Thompson, N., Wannemuehler, M., Kohut, M. Tags: ARTICLES Source Type: research
Local metabolic rate during whole body vibration
Whole body vibration (WBV) platforms are currently used for muscle training and rehabilitation. However, the effectiveness of WBV training remains elusive, since scientific studies vary largely in the vibration parameters used. The origin of this issue may be related to a lack in understanding of the training intensity that is imposed on individual muscles by WBV. Therefore, this study evaluates the training intensity in terms of metabolic rate of two lower-extremity muscles during WBV under different vibration parameters. Fourteen healthy male subjects were randomly exposed to 0 (control)-, 10-, 17-, and 28-Hz vibrations ...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Friesenbichler, B., Nigg, B. M., Dunn, J. F. Tags: ARTICLES Source Type: research
Comparison of neuromuscular adjustments associated with sustained isometric contractions of four different muscle groups
In conclusion, despite different times to task failure when sustaining an isometric contraction at 50% MVC force for as long as possible, diverse muscle groups present similar loss of MVC force after task failure. Thus the extent of muscle fatigue is not affected by time to task failure, whereas this latter determines the etiology of fatigue. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Neyroud, D., Ruttimann, J., Mannion, A. F., Millet, G. Y., Maffiuletti, N. A., Kayser, B., Place, N. Tags: ARTICLES Source Type: research
Dihydrotestosterone is elevated following sprint exercise in healthy young men
In conclusion, our data demonstrate that DHT is acutely elevated following sprint cycle exercise and that this response is influenced by cycling cadence. The importance of DHT in the context of exercise training and sports performance remains to be determined. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Smith, A. A., Toone, R., Peacock, O., Drawer, S., Stokes, K. A., Cook, C. J. Tags: ARTICLES Source Type: research
Altitude, pasture type, and sheep breed affect bone metabolism and serum 25-hydroxyvitamin D in grazing lambs
This study aimed to investigate the bone development of two mountain sheep breeds during natural summer grazing either in the lowlands or on different characteristic alpine pastures. Pasture types differed in topographic slope, plant species composition, general nutritional feeding value, Ca and P content, and Ca:P ratio of herbage. Twenty-seven Engadine sheep (ES) lambs and 27 Valaisian Black Nose sheep (VS) lambs were divided into four groups of 6 to 7 animals per breed and allocated to three contrasting alpine pasture types and one lowland pasture type. The lambs were slaughtered after 9 wk of experimental grazing. The ...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Willems, H., Leiber, F., Kohler, M., Kreuzer, M., Liesegang, A. Tags: ARTICLES Source Type: research
Two-layer model of coronary artery vasoactivity
Since vascular tone is regulated by smooth muscle cells in the media layer, a multilayer mechanical model is required for blood vessels. Here, we performed biaxial mechanical tests in the intima-media layer of right coronary artery to determine the passive and active properties in conjunction with the passive properties of adventitia for a full vessel wall model. A two-layer (intima-media and adventitia) model was developed to determine the transmural stress and stretch across the vessel wall. The mean ± SE values of the outer diameters of intima-media layers at transmural pressure of 60 mmHg in active state were 3....
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Huo, Y., Zhao, X., Cheng, Y., Lu, X., Kassab, G. S. Tags: ARTICLES Source Type: research
Airway narrowing and bronchodilation to deep inspiration in bronchial segments from subjects with and without reported asthma
The present study presents preliminary findings on how structural/functional abnormalities of the airway wall relate to excessive airway narrowing and reduced bronchodilatory response to deep inspiration (DI) in subjects with a history of asthma. Bronchial segments were acquired from subjects undergoing surgery, mostly to remove pulmonary neoplasms. Subjects reported prior doctor-diagnosed asthma (n = 5) or had no history of asthma (n = 8). In vitro airway narrowing in response to acetylcholine was assessed to determine maximal bronchoconstriction and sensitivity, under static conditions and during simulated tidal and DI m...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Noble, P. B., Jones, R. L., Cairncross, A., Elliot, J. G., Mitchell, H. W., James, A. L., McFawn, P. K. Tags: ARTICLES Source Type: research
Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements
Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left (LA) and right (RA) atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3 T, including a four-dimensional phase-contrast flow sequence. Mean LA KE was lower than RA KE (1.1 ± 0.1 vs. 1.7 ± 0.1 mJ, P < 0.01). Three KE peaks were seen in both atria: one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak (P &...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Arvidsson, P. M., Toger, J., Heiberg, E., Carlsson, M., Arheden, H. Tags: ARTICLES Source Type: research
Calpain and caspase-3 play required roles in immobilization-induced limb muscle atrophy
Prolonged skeletal muscle inactivity results in a rapid decrease in fiber size, primarily due to accelerated proteolysis. Although several proteases are known to contribute to disuse muscle atrophy, the ubiquitin proteasome system is often considered the most important proteolytic system during many conditions that promote muscle wasting. Emerging evidence suggests that calpain and caspase-3 may also play key roles in inactivity-induced atrophy of respiratory muscles, but it remains unknown if these proteases are essential for disuse atrophy in limb skeletal muscles. Therefore, we tested the hypothesis that activation of b...
Source: Journal of Applied Physiology - May 16, 2013 Category: Physiology Authors: Talbert, E. E., Smuder, A. J., Min, K., Kwon, O. S., Powers, S. K. Tags: ARTICLES Source Type: research
The ubiquitin proteasome system in human cardiomyopathies and heart failure
Maintenance of protein quality control is a critical function of the ubiquitin proteasome system (UPS). Evidence is rapidly mounting to link proteasome dysfunction with a multitude of cardiac diseases, including ischemia, reperfusion, atherosclerosis, hypertrophy, heart failure, and cardiomyopathies. Recent studies have demonstrated a remarkable level of complexity in the regulation of the UPS in the heart and suggest that our understanding of how UPS dysfunction might contribute to the pathophysiology of such a wide range of cardiac afflictions is still very limited. Whereas experimental systems, including animal models, ...
Source: AJP: Heart and Circulatory Physiology - May 15, 2013 Category: Cardiology Authors: Day, S. M. Tags: REVIEW Source Type: research
Interactions between A2A adenosine receptors, hydrogen peroxide, and KATP channels in coronary reactive hyperemia
In this study, we investigated the role of adenosine A2A and A2B receptors and their signaling mechanisms in reactive hyperemia. We hypothesized that coronary reactive hyperemia involves A2A receptors, hydrogen peroxide (H2O2), and KATP channels. We used A2A and A2B knockout (KO) and A2A/2B double KO (DKO) mouse hearts for Langendorff experiments. Flow debt for a 15-s occlusion was repaid 128 ± 8% in hearts from wild-type (WT) mice; this was reduced in hearts from A2A KO and A2A/2B DKO mice (98 ± 9 and 105 ± 6%; P < 0.05), but not A2B KO mice (123 ± 13%). Patch-clamp experiments demonstrated ...
Source: AJP: Heart and Circulatory Physiology - May 15, 2013 Category: Cardiology Authors: Sharifi-Sanjani, M., Zhou, X., Asano, S., Tilley, S., Ledent, C., Teng, B., Dick, G. M., Mustafa, S. J. Tags: VASCULAR BIOLOGY AND MICROCIRCULATION Source Type: research
Modulation of stretch-induced myocyte remodeling and gene expression by nitric oxide: a novel role for lipoma preferred partner in myofibrillogenesis
We examined the effect of cyclic mechanical stretch on myocyte adaptation using neonatal rat ventricular myocytes with 10% (adaptive) or 20% (maladaptive) maximum strain at 1 Hz for 48 h to mimic in vivo mechanical stress. Cells were also treated with and without nitro-l-arginine methyl ester (l-NAME), a general nitric oxide synthase (NOS) inhibitor to suppress NO production. Maladaptive 20% mechanical stretch led to a significant loss of intact sarcomeres that were rescued by l-NAME (P < 0.05; n ≥ 5 cultures). We hypothesized that the mechanism was through NO-induced alteration of myocyte gene expression. l-NAME upr...
Source: AJP: Heart and Circulatory Physiology - May 15, 2013 Category: Cardiology Authors: Hooper, C. L., Paudyal, A., Dash, P. R., Boateng, S. Y. Tags: SIGNALING AND STRESS RESPONSE Source Type: research
Physiologic and molecular characterization of a murine model of right ventricular volume overload
We describe the physiologic and molecular characteristics of the first murine model of RV volume overload. PI was created by entrapping the pulmonary valve leaflets with sutures. Imaging, catheterization, and exercise testing were performed at 1, 3, and 6 mo and compared with sham controls. RNA from the RV free wall was hybridized to Agilent whole genome oligonucleotide microarrays. Volume overload resulted in RV enlargement, decreased RV outflow tract shortening fraction at 1 mo followed by normalization at 3 and 6 mo (39 ± 2, 44 ± 2, and 41 ± 2 vs. 46 ± 3% in sham), early reversal of early and...
Source: AJP: Heart and Circulatory Physiology - May 15, 2013 Category: Cardiology Authors: Reddy, S., Zhao, M., Hu, D.-Q., Fajardo, G., Katznelson, E., Punn, R., Spin, J. M., Chan, F. P., Bernstein, D. Tags: SIGNALING AND STRESS RESPONSE Source Type: research