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Physiological Reports

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https://www.readbyqxmd.com/read/28912130/near-infrared-spectroscopy-of-superficial-and-deep-rectus-femoris-reveals-markedly-different-exercise-response-to-superficial-vastus-lateralis
#1
Shunsaku Koga, Dai Okushima, Thomas J Barstow, Harry B Rossiter, Narihiko Kondo, David C Poole
To date our knowledge of skeletal muscle deoxygenation as measured by near-infrared spectroscopy (NIRS) is predicated almost exclusively on sampling of superficial muscle(s), most commonly the vastus lateralis (VL-s). Recently developed high power NIRS facilitates simultaneous sampling of deep (i.e., rectus femoris, RF-d) and superficial muscles of RF (RF-s) and VL-s. Because deeper muscle is more oxidative with greater capillarity and sustains higher blood flows than superficial muscle, we used time-resolved NIRS to test the hypotheses that, following exercise onset, the RF-d has slower deoxy[Hb+Mb] kinetics with reduced amplitude than superficial muscles...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28912129/the-efficacy-of-unsupervised-home-based-exercise-regimens-in-comparison-to-supervised-laboratory-based-exercise-training-upon-cardio-respiratory-health-facets
#2
James Blackwell, Philip J Atherton, Kenneth Smith, Brett Doleman, John P Williams, Jonathan N Lund, Bethan E Phillips
Supervised high-intensity interval training (HIIT) can rapidly improve cardiorespiratory fitness (CRF). However, the effectiveness of time-efficient unsupervised home-based interventions is unknown. Eighteen volunteers completed either: laboratory-HIIT (L-HIIT); home-HIIT (H-HIIT) or home-isometric hand-grip training (H-IHGT). CRF improved significantly in L-HIIT and H-HIIT groups, with blood pressure improvements in the H-IHGT group only. H-HIIT offers a practical, time-efficient exercise mode to improve CRF, away from the laboratory environment...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28912128/aging-modifies-the-effect-of-cardiac-output-on-middle-cerebral-artery-blood-flow-velocity
#3
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
An association between cerebral blood flow (CBF) and cardiac output (CO) has been established in young healthy subjects. As of yet it is unclear how this association evolves over the life span. To that purpose, we continuously recorded mean arterial pressure (MAP; finger plethysmography), CO (pulse contour; CO-trek), mean blood flow velocity in the middle cerebral artery (MCAV; transcranial Doppler ultrasonography), and end-tidal CO2 partial pressure (PetCO2) in healthy young (19-27 years), middle-aged (51-61 years), and elderly subjects (70-79 years)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904083/assessing-the-effects-of-mitofusin-2-deficiency-in-the-adult-heart-using-3d-electron-tomography
#4
Siavash Beikoghli Kalkhoran, Andrew R Hall, Ian J White, Jackie Cooper, Qiao Fan, Sang-Bing Ong, Sauri Hernández-Reséndiz, Hector Cabrera-Fuentes, Kroekkiat Chinda, Bibhas Chakraborty, Gerald W Dorn, Derek M Yellon, Derek J Hausenloy
The effects of mitofusin 2 (MFN2) deficiency, on mitochondrial morphology and the mitochondria-junctional sarcoplasmic reticulum (jSR) complex in the adult heart, have been previously investigated using 2D electron microscopy, an approach which is unable to provide a 3D spatial assessment of these imaging parameters. Here, we use 3D electron tomography to show that MFN2-deficient mitochondria are larger in volume, more elongated, and less rounded; have fewer mitochondria-jSR contacts, and an increase in the distance between mitochondria and jSR, when compared to WT mitochondria...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904082/a-relative-l-arginine-deficiency-contributes-to-endothelial-dysfunction-across-the-stages-of-the-menopausal-transition
#5
Jelena Klawitter, Kerry L Hildreth, Uwe Christians, Wendy M Kohrt, Kerrie L Moreau
Vascular endothelial function declines across the menopause transition in women. We tested the hypothesis that reduced availability of the endothelial nitric oxide synthase [eNOS] substrate L-arginine is an underlying mechanism to vascular endothelial dysfunction across menopause stages. Endothelial function (brachial artery flow-mediated dilation [FMD]) and plasma markers of L-arginine metabolism (citrulline, N(G)-mono-methyl-ւ-arginine [L-NMMA] asymmetric dimethylarginine [ADMA] and N(G)-N('G)-dimethyl-l-arginine [SDMA]), were measured in 129 women: 36 premenopausal (33 ± 7 years), 16 early- (49 ± 3 years) or 21 late- (50 ± 4 years) perimenopausal, and 21 early- (55 ± 3 years) or 35 late- (61 ± 4 years) postmenopausal...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904081/variable-setpoint-as-a-relaxing-component-in-physiological-control
#6
Geir B Risvoll, Kristian Thorsen, Peter Ruoff, Tormod Drengstig
Setpoints in physiology have been a puzzle for decades, and especially the notion of fixed or variable setpoints have received much attention. In this paper, we show how previously presented homeostatic controller motifs, extended with saturable signaling kinetics, can be described as variable setpoint controllers. The benefit of a variable setpoint controller is that an observed change in the concentration of the regulated biochemical species (the controlled variable) is fully characterized, and is not considered a deviation from a fixed setpoint...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904080/pressure-and-stretch-differentially-affect-proliferation-of-renal-proximal-tubular-cells
#7
Diane Felsen, Bianca J Diaz, Jie Chen, Juana Gonzalez, Marie Louise V Kristensen, Anja B Bohn, Brendan T Roth, Dix P Poppas, Rikke Nørregaard
Renal obstruction is frequently found in adults and children. Mechanical stimuli, including pressure and stretch in the obstructed kidney, contribute to damage; animal models of obstruction are characterized by increased cellular proliferation. We were interested in the direct effects of pressure and stretch on renal tubular cell proliferation. Human HKC-8 or rat NRK-52E proximal tubule cells were subjected to either pressure [0, 60 or 90 mmHg] or static stretch [0 or 20%] for 24 or 48 h. Cell proliferation was measured by cell counting, cell cycle analyzed by flow cytometry, and PCNA and Skp2 expression were determined by qPCR or western blot...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904079/ascorbic-acid-promotes-a-tgf%C3%AE-1-induced-myofibroblast-phenotype-switch
#8
Bram Piersma, Olaf Y Wouters, Saskia de Rond, Miriam Boersema, Rutger A F Gjaltema, Ruud A Bank
l-Ascorbic acid (AA), generally known as vitamin C, is a crucial cofactor for a variety of enzymes, including prolyl-3-hydroxylase (P3H), prolyl-4-hydroxylase (P4H), and lysyl hydroxylase (LH)-mediated collagen maturation. Here, we investigated whether AA has additional functions in the regulation of the myofibroblast phenotype, besides its function in collagen biosynthesis. We found that AA positively influences TGFβ1-induced expression of COL1A1, ACTA2, and COL4A1 Moreover, we demonstrated that AA promotes αSMA stress fiber formation as well as the synthesis and deposition of collagens type I and IV Additionally, AA amplified the contractile phenotype of the myofibroblasts, as seen by increased contraction of a 3D collagen lattice...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899914/military-training-elicits-marked-increases-in-plasma-metabolomic-signatures-of-energy-metabolism-lipolysis-fatty-acid-oxidation-and-ketogenesis
#9
J Philip Karl, Lee M Margolis, Nancy E Murphy, Christopher T Carrigan, John W Castellani, Elisabeth H Madslien, Hilde-Kristin Teien, Svein Martini, Scott J Montain, Stefan M Pasiakos
Military training studies provide unique insight into metabolic responses to extreme physiologic stress induced by multiple stressor environments, and the impacts of nutrition in mediating these responses. Advances in metabolomics have provided new approaches for extending current understanding of factors modulating dynamic metabolic responses in these environments. In this study, whole-body metabolic responses to strenuous military training were explored in relation to energy balance and macronutrient intake by performing nontargeted global metabolite profiling on plasma collected from 25 male soldiers before and after completing a 4-day, 51-km cross-country ski march that produced high total daily energy expenditures (25...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899913/central-chemoreflex-activation-induces-sympatho-excitation-without-altering-static-or-dynamic-baroreflex-function-in-normal-rats
#10
Keita Saku, Takeshi Tohyama, Masako Shinoda, Takuya Kishi, Kazuya Hosokawa, Takuya Nishikawa, Yasuhiro Oga, Takafumi Sakamoto, Hiroyuki Tsutsui, Tadayoshi Miyamoto, Kenji Sunagawa
Central chemoreflex activation induces sympatho-excitation. However, how central chemoreflex interacts with baroreflex function remains unknown. This study aimed to examine the impact of central chemoreflex on the dynamic as well as static baroreflex functions under open-loop conditions. In 15 anesthetized, vagotomized Sprague-Dawley rats, we isolated bilateral carotid sinuses and controlled intra-sinus pressure (CSP). We then recorded sympathetic nerve activity (SNA) at the celiac ganglia, and activated central chemoreflex by a gas mixture containing various concentrations of CO2 Under the baroreflex open-loop condition (CSP = 100 mmHg), central chemoreflex activation linearly increased SNA and arterial pressure (AP)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899912/do-nitric-oxide-synthase-and-cyclooxygenase-contribute-to-sweating-response-during-passive-heating-in-endurance-trained-athletes
#11
Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo
The aim of our study was to determine if habitual endurance training can influence the relative contribution of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the regulation of sweating during a passive heat stress in young adults. Ten trained athletes and nine untrained counterparts were passively heated until oral temperature (as estimated by sublingual temperature, Tor) increased by 1.5°C above baseline resting. Forearm sweat rate (ventilated capsule) was measured at three skin sites continuously perfused with either lactated Ringer's solution (Control), 10 mmol/L N(G) -nitro-L-arginine methyl ester (L-NAME, non-selective NOS inhibitor), or 10 mmol/L ketorolac (Ketorolac, non-selective COX inhibitor) via intradermal microdialysis...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899911/correlation-of-end-tidal-carbon-dioxide-amplitude-spectrum-area-and-coronary-perfusion-pressure-in-a-porcine-model-of-cardiac-arrest
#12
Nicolas Segal, Anja K Metzger, Johanna C Moore, Laura India, Michael C Lick, Paul S Berger, Wanchun Tang, David G Benditt, Keith G Lurie
Amplitude Spectrum Area (AMSA) values during ventricular fibrillation (VF) correlate with myocardial energy stores and predict defibrillation success. By contrast, end tidal CO2 (ETCO2) values provide a noninvasive assessment of coronary perfusion pressure and myocardial perfusion during cardiopulmonary resuscitation (CPR). Given the importance of the timing of defibrillation shock delivery on clinical outcome, we tested the hypothesis that AMSA and ETCO2 correlate with each other and can be used interchangably to correlate with myocardial perfusion in an animal laboratory preclinical, randomized, prospective investigation...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899910/human-hypoxic-pulmonary-vasoconstriction-is-unaltered-by-8%C3%A2-h-of-preceding-isocapnic-hyperoxia
#13
Hung-Yuan Cheng, Quentin P P Croft, Matthew C Frise, Nick P Talbot, Nayia Petousi, Peter A Robbins, Keith L Dorrington
Exposure to sustained hypoxia of 8 h duration increases the sensitivity of the pulmonary vasculature to acute hypoxia, but it is not known whether exposure to sustained hyperoxia affects human pulmonary vascular control. We hypothesized that exposure to 8 h of hyperoxia would diminish the hypoxic pulmonary vasoconstriction (HPV) that occurs in response to a brief exposure to hypoxia. Eleven healthy volunteers were studied in a crossover protocol with randomization of order. Each volunteer was exposed to acute isocapnic hypoxia (end-tidal PO2 = 50 mmHg for 10 min) before and after 8 h of hyperoxia (end-tidal PO2 = 420 mmHg) or euoxia (end-tidal PO2 = 100 mmHg)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899909/depletion-of-the-mrna-translation-initiation-inhibitor-programmed-cell-death-protein-4-pdcd4-impairs-l6-myotube-formation
#14
Naomi Maeda, Abdikarim Abdullahi, Brendan Beatty, Zameer Dhanani, Olasunkanmi A J Adegoke
The mechanistic (mammalian) target of rapamycin complex 1 (mTORC1) signaling is vital for optimal muscle mass and function. Although the significance of mTORC1 in stimulating muscle growth is unequivocal, evidence in support of its role during muscle regeneration is less clear. Here, we showed that the abundance (protein and mRNA) of the mTORC1/S6K1 substrate, programmed cell death protein 4 (PDCD4), is upregulated at the onset of differentiation of L6 and C2C12 cells. The increase in PDCD4 was not associated with any changes in S6K1 activation, but the abundance of beta transducing repeat-containing protein (β-TrCP), the ubiquitin ligase that targets PDCD4 for degradation, increased...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28899908/activation-of-the-splenocardiac-axis-by-electronic-and-tobacco-cigarettes-in-otherwise-healthy-young-adults
#15
Zachary Boas, Pawan Gupta, Roya S Moheimani, May Bhetraratana, Fen Yin, Kacey M Peters, Jeffrey Gornbein, Jesus A Araujo, Johannes Czernin, Holly R Middlekauff
The "Splenocardiac Axis" describes an inflammatory signaling network underlying acute cardiac ischemia, characterized by sympathetic nerve stimulation of hematopoietic tissues, such as the bone marrow and spleen, which then release proinflammatory monocytes that populate atherosclerotic plaques, thereby promoting ischemic heart disease. Electronic (e) cigarettes, like tobacco cigarettes trigger sympathetic nerve activation, but virtually nothing is known about their influence on hematopoietic and vascular tissues and cardiovascular risks...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28867675/resting-sympathetic-activity-is-associated-with-the-sympathetically-mediated-component-of-energy-expenditure-following-a-meal
#16
Jacqueline K Limberg, Katherine R Malterer, Luke J Matzek, James A Levine, Nisha Charkoudian, John M Miles, Michael J Joyner, Timothy B Curry
Individuals with high plasma norepinephrine (NE) levels at rest have a smaller reduction in resting energy expenditure (REE) following β-adrenergic blockade. If this finding extends to the response to a meal, it could have important implications for the role of the sympathetic nervous system in energy balance and weight gain. We hypothesized high muscle sympathetic nerve activity (MSNA) would be associated with a low sympathetically mediated component of energy expenditure following a meal. Fourteen young, healthy adults completed two visits randomized to continuous saline (control) or intravenous propranolol to achieve systemic β-adrenergic blockade...
August 2017: Physiological Reports
https://www.readbyqxmd.com/read/28867674/acute-changes-in-extracellular-volume-fraction-in-skeletal-muscle-monitored-by-23-na-nmr-spectroscopy
#17
Teresa Gerhalter, Pierre G Carlier, Benjamin Marty
In this article, we induced acute changes in extracellular volume fraction in skeletal muscle tissue and compared the sensitivity of a standard (1)H T2 imaging method with different (23)Na-NMR spectroscopy parameters within acquisition times compatible with clinical investigations. First, we analyzed the effect of a short ischemia on the sodium distribution in the skeletal muscle. Then, the lower leg of 21 healthy volunteers was scanned under different vascular filling conditions (vascular draining, filling, and normal condition) expected to modify exclusively the extracellular volume...
August 2017: Physiological Reports
https://www.readbyqxmd.com/read/28867673/bmp7-dose-dependently-stimulates-proliferation-and-cadherin-11-expression-via-erk-and-p38-in-a-murine-metanephric-mesenchymal-cell-line
#18
Midori Awazu, Michio Nagata, Mariko Hida
BMP7 is expressed in ureteric buds and cap mesenchyme of the fetal kidney, mediating branching morphogenesis and survival and priming of metanephric mesenchyme. Although dose-dependent effects of BMP7 in collecting duct cells have been reported, studies in metanephric mesenchymal cells are lacking. We examined the effects of BMP7 on MAP kinase activation, proliferation, and expression of cadherins in a metanephric mesenchymal cell line MS7 by thymidine incorporation, immunoblot analysis, and quantitative real-time PCR The levels of phosphorylated ERK (P-ERK) and phosphorylated p38 (P-p38) were not altered at 10 min, 1 h, and 6 h with low-dose BMP7 (0...
August 2017: Physiological Reports
https://www.readbyqxmd.com/read/28867672/phagocytosis-and-inflammation-exploring-the-effects-of-the-components-of-e-cigarette-vapor-on-macrophages
#19
Miranda P Ween, Jonathan J Whittall, Rhys Hamon, Paul N Reynolds, Sandra J Hodge
E-cigarettes are perceived as harmless; however, evidence of their safety is lacking. New data suggests E-cigarettes discharge a range of compounds capable of physiological damage to users. We previously established that cigarette smoke caused defective alveolar macrophage phagocytosis. The present study compared the effect E-cigarette of components; E-liquid flavors, nicotine, vegetable glycerine, and propylene glycol on phagocytosis, proinflammatory cytokine secretion, and phagocytic recognition molecule expression using differentiated THP-1 macrophages...
August 2017: Physiological Reports
https://www.readbyqxmd.com/read/28839114/paradoxical-effect-of-ikk%C3%AE-inhibition-on-the-expression-of-e3-ubiquitin-ligases-and-unloading-induced-skeletal-muscle-atrophy
#20
Svetlana P Belova, Boris S Shenkman, Tatiana Y Kostrominova, Tatiana L Nemirovskaya
We tested whether NF-κB pathway is indispensable for the increase in expression of E3-ligases and unloading-induced muscle atrophy using IKKβ inhibitor IMD-0354. Three groups of rats were used: nontreated control (C), 3 days of unloading/hindlimb suspension with (HS+IMD) or without (HS) IMD-0354. Levels of IκBα were higher in HS+IMD (1.16-fold) and lower in HS (0.82-fold) when compared with C group. IMD-0354 treatment during unloading: had no effect on loss of muscle mass; increased mRNA levels of MuRF1 and MAFbx; increased levels of pFoxO3; and had no effect on levels of Bcl-3, p105, and p50 proteins...
August 2017: Physiological Reports
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