Read by QxMD icon Read

Journal of Applied Physiology

Swati Anil Bhatawadekar, Mark D Inman, Jeffrey J Fredberg, Susan M Tarlo, Owen D Lyons, Gabriel Keller, Azadeh Yadollahi
INTRODUCTION: In asthma, supine posture and sleep increase intrathoracic airway narrowing. When supine, due to gravity, fluid moves out of the legs and accumulates in the thorax. We hypothesized that fluid shift out of the legs into the thorax contributes to the intrathoracic airway narrowing in asthma. METHODS: Healthy and asthmatic subjects sat for 30min and then lay supine for 30min. To simulate overnight fluid shift, supine subjects were randomized to receive increased fluid shift out of the legs using lower body positive pressure (LBPP, 10 to 30min) or none (control), and crossed over...
January 12, 2017: Journal of Applied Physiology
Grace M Niemiro, Justin Parel, Joseph Beals, Stephan van Vliet, Scott A Paluska, Daniel Ryan Moore, Nicholas A Burd, Michael De Lisio
Circulating progenitor cells (CPCs) are a heterogeneous population of stem/progenitor cells in peripheral blood that includes hematopoietic stem and progenitor cells (HSPCs and HSCs), endothelial progenitor cells (EPCs), and mesenchymal stem cells (MSCs). CPC mobilization during exercise remains uncharacterized in young adults. The purpose of this study was to investigate the kinetics of CPC mobilization during and after submaximal treadmill running and their relationship to mobilization factors. Seven men (age=25...
January 12, 2017: Journal of Applied Physiology
Ryan L Hoiland, Anthony Richard Bain, Michael M Tymko, Mathew G Rieger, Connor A Howe, Christopher K Willie, Alex B Hansen, Daniela Flück, Kevin W Wildfong, Mike Stembridge, Prajan Subedi, James D Anholm, Philip N Ainslie
Hypoxia increases cerebral blood flow (CBF) with the underlying signaling processes potentially including adenosine. A randomized, double-blinded, placebo controlled design, was implemented to determine if adenosine receptor antagonism (theophylline, 3.75 mg/Kg) would reduce the CBF response to normobaric and hypobaric hypoxia. In 12 participants the partial pressures of end-tidal oxygen (PETO2) and carbon dioxide (PETCO2), ventilation (pneumotachography), blood pressure (finger-photoplethysmography), heart-rate (electrocardiogram), CBF (duplex ultrasound), and intra-cranial blood velocities (transcranial Doppler ultrasound) were measured during five-minute stages of isocapnic hypoxia at sea-level (98, 90, 80, & 70% SaO2)...
January 12, 2017: Journal of Applied Physiology
Mark S Miller, Damien M Callahan, Timothy W Tourville, James R Slauterbeck, Anna Kaplan, Brad R Fiske, Patrick D Savage, Philip A Ades, Bruce D Beynnon, Michael J Toth
High-intensity resistance exercise (REX) training increases physical capacity, in part, by improving muscle cell size and function. Moderate-intensity REX, which is more feasible for many older adults with disease and disability, also increases physical function, but the mechanisms underlying such improvements are not understood. Therefore, we measured skeletal muscle structure and function from the molecular to the tissue level in response to 14 weeks of moderate-intensity, REX in physically-inactive, older adults with knee osteoarthritis (n=17; 70 +/- 1 yrs)...
January 12, 2017: Journal of Applied Physiology
Anne-Sophie G T Bronzwaer, Jasper Verbree, Wim J Stok, Mat J A P Daemen, Mark A van Buchem, Matthias J P van Osch, Johannes J Van Lieshout
Lower body negative pressure (LBNP) has been proposed as a MRI-compatible surrogate for orthostatic stress. Although the effects of LBNP on cerebral hemodynamic behavior have been considered to reflect those of orthostatic stress, a direct comparison with actual orthostasis is lacking. We assessed the effects of LBNP (-50 mmHg) versus head-up tilt (HUT; at 70°) in 10 healthy subjects (5 female) on transcranial Doppler determined cerebral blood flow velocity (CBFv) in the middle cerebral artery and cerebral perfusion pressure (CPP) as estimated from the blood pressure signal (finger plethysmography)...
January 12, 2017: Journal of Applied Physiology
Noah P Jouett, Gilbert Moralez, Peter B Raven, Michael L Smith
Obstructive sleep apnea (OSA) is characterized by intermittent hypoxemia (IH), which produces elevations in sympathetic nerve activity (SNA) and associated hypertension in experimental models that persist beyond the initial exposure. We tested the hypotheses that angiotensin receptor blockade in humans using Losartan attenuates the immediate and immediately persistent increases in (a) SNA discharge and (b) mean arterial pressure (MAP) after hyper-acute intermittent hypoxia training (IHT) using a randomized, placebo controlled repeated-measures experimental design...
January 12, 2017: Journal of Applied Physiology
Nathalie Pattyn, Olivier Mairesse, Aisha Cortoos, Nele Marcoen, Xavier Neyt, Romain Meeusen
Sleep complaints are consistently cited as the most prominent health and well-being problem in Arctic and Antarctic expeditions, without clear evidence to identify the causal mechanisms. The present investigation aimed at studying sleep and determining circadian regulation and mood during a 4 months Antarctic summer expedition. All data collection was performed during the continuous illumination of the Antarctic summer. After an habituation night and acclimatization to the environment (3 weeks), ambulatory polysomnography (PSG) was performed in 21 healthy male subjects, free of medication...
January 12, 2017: Journal of Applied Physiology
Stian Kwak Nyberg, Ole Kristian Berg, Jan Helgerud, Eivind Wang
The vascular strain is very high during heavy handgrip exercise, but the intensity and kinetics to reach peak blood flow, and peak oxygen uptake, are uncertain. We included 9 young (25±2yr) healthy males to evaluate blood flow and oxygen uptake responses during continuous dynamic handgrip exercise with increasing intensity. Blood flow was measured using Doppler-ultrasound and venous blood was drawn from a deep forearm vein to determine arteriovenous oxygen difference (a-vO2diff) during 6-minutes bouts of 60, 80 and 100% of maximal work rate (WRmax), respectively...
January 5, 2017: Journal of Applied Physiology
Theodore R Mellors, Lionel Blanchet, JoAnne L Flynn, Jaime Tomko, Melanie O'Malley, Charles A Scanga, Philana L Lin, Jane E Hill
Breath is hypothesized to contain clinically relevant information, useful for the diagnosis and monitoring of disease, as well as understanding underlying pathogenesis. Non-human primates, such as the cynomolgus macaque, serve as an important model for the study of human disease, including over 70 different human infections. In this feasibility study, exhaled breath was successfully collected in less than five minutes under Biosafety Level 3 conditions from five anesthetized, intubated cynomolgus and rhesus macaques, before and after lung infection with M...
January 5, 2017: Journal of Applied Physiology
Gwenaelle Begue, Ulrika Raue, Bozena Jemiolo, Scott W Trappe
A new application of the Reduced Representation Bisulfite Sequencing method was developed using low-DNA input to investigate the epigenetic profile of human slow- and fast-twitch skeletal muscle fibers. Successful library construction was completed with as little as 15 ng of DNA and high quality sequencing data were obtained with 32 ng of DNA. Analysis identified 143,160 differentially methylated CpG-sites across 14,046 genes. In both fiber types, selected genes predominantly expressed in slow or fast fibers were hypomethylated, which was supported by the RNA-Seq analysis...
January 5, 2017: Journal of Applied Physiology
Roberta Francesca Capogrosso, Paola Mantuano, Anna Cozzoli, Francesca Sanarica, Ada Maria Massari, Elena Conte, Adriano Fonzino, Arcangela Giustino, Jean-Francois Rolland, Angelo Quaranta, Michela De Bellis, Giulia Maria Camerino, Robert W Grange, Annamaria De Luca
Progressive weakness is a typical feature of Duchenne muscular dystrophy (DMD) patients and is exacerbated in the benign mdx mouse model by in vivo treadmill exercise. We hypothesized a different threshold for functional adaptation of mdx muscles in response to the duration of the exercise protocol. In vivo weakness was confirmed by grip strength after 4, 8 and 12 weeks of exercise in mdx mice. Torque measurements revealed that exercise-related weakness in mdx mice correlated with the duration of the protocol, while wild-type (wt) mice were stronger...
January 5, 2017: Journal of Applied Physiology
Eiichiro Yamaguchi, Liam P Nolan, Donald P Gaver
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 micro-fluidic idealized in vitro models of bifurcating airways, through which we can independently evaluate the impact of carina location, and the 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 and capillary pressure drops (PHyd and PCap, respectively)...
January 5, 2017: Journal of Applied Physiology
Michael D Patz, Rui Carlos Sá, Chantal Darquenne, Ann R Elliott, Amran K Assadi, Rebecca J Theilmann, David J Dubowitz, Erik Richard Swenson, Gordon Kim Prisk, Susan Roberta Hopkins
High altitude pulmonary edema (HAPE) is a potentially fatal condition affecting high altitude sojourners. The biggest predictor of HAPE development is a history of prior HAPE. Magnetic resonance imaging (MRI) shows HAPE-susceptible, with a history of HAPE, but not HAPE-resistant (a history of repeated ascents without illness) individuals develop greater heterogeneity of regional pulmonary perfusion breathing hypoxic gas (O2=12.5%), consistent with uneven hypoxic pulmonary vasoconstriction (HPV). Why HPV is uneven in HAPE-susceptibles is unknown, but may arise from regionally heterogeneous ventilation resulting in an uneven stimulus to HPV...
January 5, 2017: Journal of Applied Physiology
Ryan M Sapp, Daniel D Shill, Stephen M Roth, James M Hagberg
MicroRNAs (miRNAs) are short, non-coding RNAs that influence biological processes by regulating gene expression post-transcriptionally. It was recently discovered that miRNAs are released into the circulation (ci-miRNAs) where they are highly stable and can act as intercellular messengers to affect physiological processes. This review provides a comprehensive summary of the studies, to date, that have investigated the effects of acute exercise and exercise training on ci-miRNAs in humans. Findings indicate that specific ci-miRNAs are altered in response to different protocols of acute and chronic exercise in both healthy and diseased populations...
December 29, 2016: Journal of Applied Physiology
Jonathan M Peake, Oliver Neubauer, Paul A Della Gatta, Kazunori Nosaka
Unaccustomed exercise consisting of eccentric (i.e., lengthening) muscle contractions often results in muscle damage characterized by ultrastructural alterations in muscle tissue, clinical signs and symptoms (e.g., reduced muscle strength and range of motion, increased muscle soreness and swelling, efflux of myocellular proteins). The time course of recovery following exercise-induced muscle damage depends on the extent of initial muscle damage, which in turn is influenced by the intensity and duration of exercise, joint angle/muscle length and muscle groups used during exercise...
December 29, 2016: Journal of Applied Physiology
Matthew D Muller, Tariq Ali Ahmad, Alvaro F Vargas Pelaez, David N Proctor, Anthony S Bonavia, J Carter Luck, Stephan R Maman, Amanda J Ross, Urs A Leuenberger, Patrick M McQuillan
Despite its widespread clinical use, the β1 adrenergic receptor antagonist esmolol hydrochloride is not commonly used in human physiology research and the effective dose (compared to the nonselective β-blocker propranolol) is unclear. In four separate studies, we used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate (HR)- lowering effect of esmolol compared to propranolol and saline in healthy humans. In Cohort 1, both esmolol (ΔHR: 57 ± 6) and propranolol (ΔHR: 56 ± 7) attenuated exercise tachycardia compared to saline (ΔHR: 88 ± 17)...
December 29, 2016: Journal of Applied Physiology
Veronique Louise Billat, Gilles Dhonneur, Laurence Mille-Hamard, Laurence Le Moyec, Iman Momken, Thierry Launay, Jean-Pierre Koralsztein, Sophie Besse
: The purpose of this study was to examine the physiological characteristics of an elite centenarian cyclist who, at 101 years old, established the one-hour cycling record for individuals ≥ 100 years old (24.25 km) and to determine the physiological factors associated with his performance improvement two years later at 103 years old (26.92 km; +11%). Before each record, he performed an incremental test on a cycling ergometer. For two years, he trained 5,000 km a year with a polarized training that involved cycling 80% of mileage at "light" RPE ≤ 12 and 20% at "hard" RPE ≥ 15 at a cadence between 50 and 70 rpm...
December 29, 2016: Journal of Applied Physiology
Stephen Dubsky, Graeme R Zosky, Kara Perks, Chaminda R Samarage, Yann Henon, Stuart B Hooper, Andreas Fouras
Detailed information on the distribution of airway diameters during bronchoconstriction in situ is required in order to understand the regional response of the lungs. Imaging studies using computed tomography (CT) have previously measured airway diameters and changes in response to bronchoconstricting agents, but the manual measurements used have severely limited the number of airways measured per subject. Hence, the detailed distribution and heterogeneity of airway responses is unknown. We have developed and applied dynamic imaging and advanced image-processing methods to quantify and compare hundreds of airways in vivo...
December 29, 2016: Journal of Applied Physiology
Alexandra Malgoyre, Clovis Chabert, Julia Tonini, Nathalie Koulmann, Xavier Bigard, Hervé Sanchez
We investigated the effects of chronic hypoxia on the maximal use of and sensitivity of mitochondrial to different substrates in rat slow-oxidative (soleus, SOL) and fast-glycolytic (extensor digitorum longus, EDL) muscles. We studied mitochondrial respiration in situ in permeabilized myofibers, using pyruvate, octanoate, palmitoyl-carnitine (PC) or palmitoyl-coenzyme A (PCoA). The hypophagia induced by hypoxia may also alter metabolism. We therefore used a group of pair-fed rats (reproducing the same caloric restriction as observed in hypoxic animals) in addition to the normoxic control fed ad libitum...
December 29, 2016: Journal of Applied Physiology
Matthew I Black, Andrew M Jones, Jamie R Blackwell, Stephen J Bailey, Lee J Wylie, Sinead T J McDonagh, Christopher Thompson, James Kelly, Paul Sumners, Katya J Mileva, Joanna L Bowtell, Anni Vanhatalo
The lactate or gas exchange threshold (GET) and the critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven males performed a ramp incremental exercise test, 4-5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; <CP but >GET) CWR test until Tlim, and a moderate-intensity (MOD; <GET) CWR test until Tlim Muscle biopsies revealed that a similar (P>0...
December 22, 2016: Journal of Applied Physiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"