Microscale distribution and dynamic surface tension of pulmonary surfactant normalize the recruitment of asymmetric bifurcating airways
We investigate the influence of bifurcation geometry, asymmetry of daughter airways, surfactant distribution, and physicochemical properties on the uniformity of airway recruitment of asymmetric bifurcating airways. To do so, we developed microfluidic idealized in vitro models of bifurcating airways, through which we can independently evaluate the impact of carina location and daughter airway width and length. We explore the uniformity of recruitment and its relationship to the dynamic surface tension of the lining fluid and relate this behavior to the hydraulic (PHyd) and capillary (PCap) pressure drops. These studies dem...
Source: Journal of Applied Physiology - May 9, 2017 Category: Physiology Authors: Yamaguchi, E., Nolan, L. P., Gaver, D. P. Tags: RESEARCH ARTICLE Source Type: research
Quantitative MRI volumetry, diffusivity, cerebrovascular flow, and cranial hydrodynamics during head-down tilt and hypercapnia: the SPACECOT study
To improve the pathophysiological understanding of visual changes observed in astronauts, we aimed to use quantitative MRI to measure anatomic and physiological responses during a ground-based spaceflight analog (head-down tilt, HDT) combined with increased ambient carbon dioxide (CO2). Six healthy, male subjects participated in the double-blinded, randomized crossover design study with two conditions: 26.5 h of –12° HDT with ambient air and with 0.5% CO2, both followed by 2.5-h exposure to 3% CO2. Volume and mean diffusivity quantification of the lateral ventricle and phase-contrast flow sequences of the interna...
Source: Journal of Applied Physiology - May 9, 2017 Category: Physiology Authors: Kramer, L. A., Hasan, K. M., Sargsyan, A. E., Marshall-Goebel, K., Rittweger, J., Donoviel, D., Higashi, S., Mwangi, B., Gerlach, D. A., Bershad, E. M., SPACECOT Investigators Group Tags: RESEARCH ARTICLE Source Type: research
Exercise-induced upregulation of endothelial adhesion molecules in human skeletal muscle and number of circulating cells with remodeling properties
In conclusion, exercise increases MO subsets with different temporal patterns and enhances the capacity of skeletal muscle tissue to recruit circulating cells as shown by increased expression of endothelial adhesion molecules.
NEW & NOTEWORTHY In the present study we showed for the first time that the adhesion molecules ICAM-1, VCAM-1, and E-selectin, known to be able to recruit circulating cells to the peripheral tissue, increased in exercised human skeletal muscle concurrently with increased circulating levels of cells shown to have importance for skeletal muscle remodeling. These findings support the concept of cell...
Source: Journal of Applied Physiology - May 9, 2017 Category: Physiology Authors: Strömberg, A., Rullman, E., Jansson, E., Gustafsson, T. Tags: RESEARCH ARTICLE Source Type: research
Frequency characteristics of human muscle and cortical responses evoked by noisy Achilles tendon vibration
Noisy stimuli, along with linear systems analysis, have proven to be effective for mapping functional neural connections. We explored the use of noisy (10–115 Hz) Achilles tendon vibration to examine somatosensory reflexes in the triceps surae muscles in standing healthy young adults (n = 8). We also examined the association between noisy vibration and electrical activity recorded over the sensorimotor cortex using electroencephalography. We applied 2 min of vibration and recorded ongoing muscle activity of the soleus and gastrocnemii using surface electromyography (EMG). Vibration amplitude was varied to characteriz...
Source: Journal of Applied Physiology - May 9, 2017 Category: Physiology Authors: Mildren, R. L., Peters, R. M., Hill, A. J., Blouin, J.-S., Carpenter, M. G., Inglis, J. T. Tags: INNOVATIVE METHODOLOGY Source Type: research
Dynamics of middle cerebral artery blood flow velocity during moderate-intensity exercise
We report a novel method of measuring cerebrovascular blood velocity (MCAv) kinetics under ecologically valid conditions from rest to moderate-intensity exercise. This technique reveals that brain blood flow increases exponentially following the onset of exercise with 1) a strong bilateral coherence in young healthy individuals, and 2) a potential for unique age- and disease-specific profiles. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 9, 2017 Category: Physiology Authors: Billinger, S. A., Craig, J. C., Kwapiszeski, S. J., Sisante, J.-F. V., Vidoni, E. D., Maletsky, R., Poole, D. C. Tags: INNOVATIVE METHODOLOGY Source Type: research
Acute intermittent hypoxia in rats activates muscle proteolytic pathways through a gluccorticoid-dependent mechanism
Although it is well known that chronic hypoxia induces muscle wasting, the effects of intermittent hypoxia on skeletal muscle protein metabolism remain unclear. We hypothesized that acute intermittent hypoxia (AIH), a challenge that activates the hypothalamic-pituitary-adrenal axis, would alter muscle protein homeostasis through a glucocorticoid-dependent mechanism. Three-week-old rats were submitted to adrenalectomy (ADX) and exposed to 8 h of AIH (6% O2 for 40 s at 9-min intervals). Animals were euthanized, and the soleus and extensor digitorum longus (EDL) muscles were harvested and incubated in vitro for measurements o...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Przygodda, F., Manfredi, L. H., Machado, J., Goncalves, D. A. P., Zanon, N. M., Bonagamba, L. G. H., Machado, B. H., Kettelhut, I. C., Navegantes, L. C. C. Tags: RESEARCH ARTICLE Source Type: research
Comparison between the phase angle and phase shift parameters to assess thoracoabdominal asynchrony in COPD patients
This study contributes to advance the knowledge over the previous lack of consensus on the assessment of thoracoabdominal asynchrony. We rigorously evaluated the related features that interfere in the measurement of the asynchrony (measurement tool, chest wall model and calculation parameter). Our results suggest that phase angle detects more suitably thoracoabdominal asynchrony that occurs on the lower ribcage and leads to a reduction in the chest wall volume during exercise in COPD patients. (Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Cano Porras, D., Lunardi, A. C., Marques da Silva, C. C. B., Paisani, D. M., Stelmach, R., Moriya, H. T., Carvalho, C. R. F. Tags: RESEARCH ARTICLE Source Type: research
Involvement of glycogen synthase kinase-3{beta} in liver ischemic conditioning induced cardioprotection against myocardial ischemia and reperfusion injury in rats
Remote ischemic conditioning has been convincingly shown to render the myocardium resistant to a subsequent more severe sustained episode of ischemia. Compared with other organs, little is known regarding the effect of transient liver ischemic conditioning. We proposed the existence of cardioprotection induced by remote liver conditioning. Male Sprague-Dawley rats were divided into sham-operated control (no further hepatic intervention) and remote liver ischemic conditioning groups. For liver ischemic conditioning, three cycles of 5 min of liver ischemia-reperfusion stimuli were conducted before-(liver preconditioning), po...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Yang, S., Abbott, G. W., Gao, W. D., Liu, J., Luo, C., Hu, Z. Tags: RESEARCH ARTICLE Source Type: research
Development of a technique for determination of pulmonary artery pulse wave velocity in horses
This study aimed to develop a technique to determine PA-PWV in horses and, secondarily, to investigate a potential association between PA-PWV and arterial fibro-calcification. A dual-pressure sensor catheter (PSC) was placed in the main PA of 10 sedated horses. The pressure waves were used to determine PWV along the PA, using the statistical phase offset method. Histological analysis of the PA was performed to investigate the presence of fibro-calcified lesions. The mean (±SD) PWV was 2.3 ± 0.7 m/s in the proximal PA trunk and 1.1 ± 0.1 m/s further distal (15 cm) in a main PA branch. The mean (±...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Silva, G. T. d. A., Guest, B. B., Gomez, D. E., McGregor, M., Viel, L., OSullivan, M. L., Runciman, J., Arroyo, L. G. Tags: INNOVATIVE METHODOLOGY Source Type: research
Recovery of the immune system after exercise
The notion that prolonged, intense exercise causes an "open window" of immunodepression during recovery after exercise is well accepted. Repeated exercise bouts or intensified training without sufficient recovery may increase the risk of illness. However, except for salivary IgA, clear and consistent markers of this immunodepression remain elusive. Exercise increases circulating neutrophil and monocyte counts and reduces circulating lymphocyte count during recovery. This lymphopenia results from preferential egress of lymphocyte subtypes with potent effector functions [e.g., natural killer (NK) cells, T cells, and CD8+ T c...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Peake, J. M., Neubauer, O., Walsh, N. P., Simpson, R. J. Tags: REVIEW Source Type: research
Recovery of central and peripheral neuromuscular fatigue after exercise
Sustained physical exercise leads to a reduced capacity to produce voluntary force that typically outlasts the exercise bout. This "fatigue" can be due both to impaired muscle function, termed "peripheral fatigue," and a reduction in the capacity of the central nervous system to activate muscles, termed "central fatigue." In this review we consider the factors that determine the recovery of voluntary force generating capacity after various types of exercise. After brief, high-intensity exercise there is typically a rapid restitution of force that is due to recovery of central fatigue (typically within 2 min) and aspects of...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Carroll, T. J., Taylor, J. L., Gandevia, S. C. Tags: REVIEW Source Type: research
Postexercise muscle glycogen resynthesis in humans
Since the pioneering studies conducted in the 1960s in which glycogen status was investigated using the muscle biopsy technique, sports scientists have developed a sophisticated appreciation of the role of glycogen in cellular adaptation and exercise performance, as well as sites of storage of this important metabolic fuel. While sports nutrition guidelines have evolved during the past decade to incorporate sport-specific and periodized manipulation of carbohydrate (CHO) availability, athletes attempt to maximize muscle glycogen synthesis between important workouts or competitive events so that fuel stores closely match th...
Source: Journal of Applied Physiology - May 1, 2017 Category: Physiology Authors: Burke, L. M., van Loon, L. J. C., Hawley, J. A. Tags: REVIEW Source Type: research
Corrigendum
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - April 18, 2017 Category: Physiology Tags: CORRIGENDA Source Type: research
Muscle damage: Scientific fundamentals
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - April 18, 2017 Category: Physiology Authors: Mirzayev, J. A. Tags: LETTERS TO THE EDITOR Source Type: research
Work of breathing and sleep pattern behavior in COPD. How much oxygen or high-flow nasal cannula?
(Source: Journal of Applied Physiology)
Source: Journal of Applied Physiology - April 18, 2017 Category: Physiology Authors: Silva Santos, P., Cruz, C., Esquinas, A. M. Tags: LETTERS TO THE EDITOR Source Type: research
