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Physiological Reports

Andrea Nicolò, Michele Girardi, Ilenia Bazzucchi, Francesco Felici, Massimo Sacchetti
Differentiating between respiratory frequency (fR ) and tidal volume (VT ) may improve our understanding of exercise hyperpnoea because fR and VT seem to be regulated by different inputs. We designed a series of exercise manipulations to improve our understanding of how fR and VT are regulated during exercise. Twelve cyclists performed an incremental test and three randomized experimental sessions in separate visits. In two of the three experimental visits, participants performed a moderate-intensity sinusoidal test followed, after recovery, by a moderate-to-severe-intensity sinusoidal test...
November 2018: Physiological Reports
Severin Ruoss, Philipp Kindt, Linus Oberholzer, Marco Rohner, Ladina Jungck, Sara Abdel-Aziz, Daniel Fitze, Andrea B Rosskopf, Karina Klein, Brigitte von Rechenberg, Christian Gerber, Karl Wieser, Martin Flück
Chronic rotator cuff (RC) tears are characterized by retraction, fat accumulation, and atrophy of the affected muscle. These features pose an intractable problem for surgical repair and subsequent recovery, and their prevention may be easier than reversal. Using an established ovine model, we tested the hypothesis that inhibition of the protease calpain mitigates m. infraspinatus atrophy by preservation of the myofibers' structural anchors in the sarcolemma (the costameres). Already 2 weeks of distal tendon release led to a reduction in muscle volume (-11...
November 2018: Physiological Reports
Robert M Gifford, Christopher J Boos, Rebecca M Reynolds, David R Woods
The relationship between autonomic function and recovery following prolonged arduous exercise in women has not been examined. We undertook an exploratory study that aimed to examine the temporal change in linear and nonlinear measures of heart rate variability (HRV) following prolonged arduous exercise in the form of first all-female (mean age 32.7 ± 3.1 years) team to attempt an unassisted Antarctic traverse. HRV analysis was performed before and 1, 4, and 15 days postexpedition. The traverse was completed in 61 days...
November 2018: Physiological Reports
Hitoshi Wakabayashi, Mizuki Osawa, Shunsaku Koga, Ke Li, Hiroyuki Sakaue, Yasuo Sengoku, Hideki Takagi
This study investigated effects of skeletal muscle cooling on the metabolic response and kinetics of pulmonary oxygen uptake ( <mml:math xmlns:mml=""> <mml:mover> <mml:mi>V</mml:mi> <mml:mo>˙</mml:mo> </mml:mover> </mml:math> O2 ) and skeletal muscle deoxygenation during submaximal exercise. In the cooling condition (C), after immersion of the lower body into 12°C water for 30 min, eight healthy males performed 30-min cycling exercise at the lactate threshold while undergoing thigh cooling by a water-circulating pad...
November 2018: Physiological Reports
Daphne P M de Wijs-Meijler, Dirk J Duncker, A H Jan Danser, Irwin K M Reiss, Daphne Merkus
Neonatal pulmonary vascular disease (PVD) is increasingly recognized as a disease that complicates the cardiopulmonary adaptations after birth and predisposes to long-term cardiopulmonary disease. There is growing evidence that PVD is associated with disruptions in the nitric oxide (NO)-cGMP-phosphodiesterase 5 (PDE5) pathway. Examination of the functionality of different parts of this pathway is required for better understanding of the pathogenesis of neonatal PVD. For this purpose, the role of the NO-cGMP-PDE5 pathway in regulation of pulmonary vascular function was investigated in vivo, both at rest and during exercise, and in isolated pulmonary small arteries in vitro, in a neonatal swine model with hypoxia-induced PVD...
October 2018: Physiological Reports
Mikako Harata, Siming Liu, Joseph A Promes, Anthony J Burand, James A Ankrum, Yumi Imai
Rodent islets are widely used to study the pathophysiology of beta cells and islet function, however, structural and functional differences exist between human and rodent islets, highlighting the need for human islet studies. Human islets are highly variable, deteriorate during culture, and are difficult to genetically modify, making mechanistic studies difficult to conduct and reproduce. To overcome these limitations, we tested whether pseudoislets, created by dissociation and reaggregation of islet cell suspensions, allow for assessment of dynamic islet function after genetic modulation...
October 2018: Physiological Reports
Gioia Tartaglione, Giuseppe Spaziano, Manuela Sgambato, Teresa Palmira Russo, Angela Liparulo, Renata Esposito, Salvatore Mirra, Rosanna Filosa, Fiorentina Roviezzo, Francesca Polverino, Bruno D'Agostino
It is widely recognized that airway inflammation and remodeling play a key role not only in the central airway but also small airway pathology during asthma. Nociceptin/Orphanin FQ (N/OFQ), an endogenous peptide, and its receptor N/OFQ peptide (NOP) are involved in airway hyperresponsiveness (AHR). We studied a murine model of AHR in order to understand the role of N/OFQ in the inflammation and remodeling of the small airways. Balb/c mice were sensitized to ovalbumin (OVA). At days 0 and 7 (pre-OVA sensitization) or from day 21 to 23 (post-OVA sensitization), the mice were treated intraperitoneally with N/OFQ or saline solution...
October 2018: Physiological Reports
Nina Brandt, Dorota Kotowska, Caroline M Kristensen, Jesper Olesen, Ditte O Lützhøft, Jens F Halling, Martin Hansen, Waleed A Al-Soud, Lars Hansen, Pia Kiilerich, Henriette Pilegaard
The aim of this study was to examine the effect of exercise training and dietary supplementation of resveratrol on the composition of gut microbiota and to test the hypothesis that exercise training and resveratrol can prevent high-fat diet (HFD)-induced changes in the gut microbiota. Mice fed a HFD supplemented with resveratrol (4 g/kg food) were protected against diet-induced obesity, while exercise trained HFD-fed animals (running on average 50 km/week) were not. Dietary resveratrol supplementation induced changes predominantly in the low-abundant bacteria, while exercise training induced changes in the high-abundant bacteria in the gut as analyzed by ADONIS test with Weighted UniFrac distances...
October 2018: Physiological Reports
James R Sackett, Zachary J Schlader, Carol Cruz, David Hostler, Blair D Johnson
The partial pressure of end tidal carbon dioxide (PETCO2 ), ventilatory sensitivity to CO2 , and cerebral perfusion are augmented during thermoneutral head out water immersion (HOWI). We tested the hypotheses that HOWI and acute hypercapnia augments minute ventilation, ventilatory sensitivity to CO2 , cerebral perfusion, and cerebrovascular reactivity to CO2 . Twelve subjects (age: 24 ± 3 years, BMI: 25.3 ± 2.9 kg/m2 , 6 women) participated in two experimental visits: a HOWI visit (HOWI) and a matched hypercapnia visit (Dry + CO2 )...
October 2018: Physiological Reports
Takumi Yokokawa, Kohei Kido, Tadashi Suga, Tadao Isaka, Tatsuya Hayashi, Satoshi Fujita
The process of mitochondrial translation, in which mitochondrial (mt)DNA-encoded genes are translated into proteins, is crucial for mitochondrial function and biogenesis. In each phase, a series of mitochondrial translation factors is required for the synthesis of mtDNA-encoded mitochondrial proteins. Two mitochondrial initiation factors (mtIF2 and mtIF3), three mitochondrial elongation factors (mtEFTu, mtEFTs, and mtEFG1), one mitochondrial release factor (mtRF1L), and two mitochondrial recycling factors (mtRRF1 and mtRRF2) are mitochondrial translation factors that coordinate each translational phase...
October 2018: Physiological Reports
Cecilia Y Cheung, Victoria H J Roberts, Antonio E Frias, Robert A Brace
During pregnancy, high fat diet (HFD) induces maternal obesity, insulin resistance, and placental inflammatory responses that compromise placental and fetal development. Whether maternal HFD would adversely affect amniotic fluid volume (AFV) has not been explored. Vascular endothelial growth factor (VEGF) is expressed in the amnion and has been proposed as a regulator of AFV. Our aim was to investigate the effects of HFD on AFV and the associated changes in VEGF and soluble VEGF receptor 1 (sFlt-1) expression profiles in three amnion regions of a nonhuman primate model...
October 2018: Physiological Reports
Jae-Hoon Chung, Benjamin D Canan, Bryan A Whitson, Ahmet Kilic, Paul M L Janssen
In this study, we investigated the quantitative and qualitative role of the sarcoplasmic reticulum (SR) in the regulation of the force-frequency relationship (FFR). We blocked the function of SR with cyclopiazonic acid (CPA) and ryanodine and measured twitch kinetics and developed force at various stimulation frequencies in nonfailing and failing intact human right ventricular trabeculae. We found that developed forces are only slightly reduced upon SR blockade, while the positive FFR in nonfailing trabeculae and negative FFR in failing trabeculae were both preserved...
October 2018: Physiological Reports
Mohamed Issouf, Amandine Vargas, Roxane Boivin, Jean-Pierre Lavoie
Smooth muscle has a central role in bronchospasm-induced airway obstruction in asthma. Alternative mRNA splicing of the smooth muscle myosin heavy chain (myh11) gene produces four different isoforms, one of which (SMB) is characterized by the inclusion of the exon5b, which doubles the smooth muscle cells contraction velocity. Deciphering the regulation of the expression levels of the SMB isoform would represent a major step for the understanding of the triggers and pathways leading to airway smooth muscle contraction in asthma...
October 2018: Physiological Reports
Marcelo B Bastos, Elske T Massolt, Boen L R Kam, Robin P Peeters, Nicolas M Van Mieghem, W Edward Visser, Corstiaan A den Uil
Thyroid hormone importantly affects the cardiovascular system. However, evaluation of stroke volume (SV) and its determinants is confounded by variations in volume status that occur along different thyroid states. This study applied the pressure-volume (PV) framework to obtain relatively load-independent estimates of cardiac function in hypothyroidism as compared to euthyroidism. Ten athyroid patients were assessed echocardiographically after 4 weeks in deep hypothyroid state, and again after supplementation with oral Levothyroxine (LT4) for 3 months...
October 2018: Physiological Reports
Hailu K Alemayehu, Desy Salvadego, Miriam Isola, Gabriella Tringali, Roberta De Micheli, Mara Caccavale, Alessandro Sartorio, Bruno Grassi
Obese adolescents (OB) have an increased O2 cost of exercise, attributable in part to an increased O2 cost of breathing. In a previous work a short (3-week) program of respiratory muscle endurance training (RMET) slightly reduced in OB the O2 cost of high-intensity cycling and improved exercise tolerance. We hypothesized that during treadmill walking the effects of RMET would be more pronounced than those observed during cycling. Sixteen OB (age 16.0 ± 0.8 years; body mass [BM] 127.7 ± 14.2 kg; body mass index 40...
October 2018: Physiological Reports
Eilidh Craigie, Robert I Menzies, Casper K Larsen, Grégory Jacquillet, Monique Carrel, Scott S Wildman, Johannes Loffing, Jens Leipziger, David G Shirley, Matthew A Bailey, Robert J Unwin
In the kidney, purinergic (P2) receptor-mediated ATP signaling has been shown to be an important local regulator of epithelial sodium transport. Appropriate sodium regulation is crucial for blood pressure (BP) control and disturbances in sodium balance can lead to hypo- or hypertension. Links have already been established between P2 receptor signaling and the development of hypertension, attributed mainly to vascular and/or inflammatory effects. A transgenic mouse model with deletion of the P2X4 receptor (P2X4-/- ) is known to have hypertension, which is thought to reflect endothelial dysfunction and impaired nitric oxide (NO) release...
October 2018: Physiological Reports
Joshua D Winward, Christina M Ragan, Ana G Jimenez
Life-history theory posits that differences in reproductive strategies may dictate lifespans of organisms. Animals that have higher investments in reproduction in terms of litter size and frequency of litters tend to have shorter lifespans. The accumulation of oxidative stress damage has been proposed to be a cost of reproduction and a mediator of life-histories among animals, however, the implications of reproduction on oxidative stress still remain unclear. We tested physiological consequences of reproduction on metabolism and oxidative stress of Sprague-Dawley Rats (Rattus norvegicus) with various reproductive experiences at the cell level...
October 2018: Physiological Reports
John B West
Pulmonary gas exchange is the primary function of the lung, and during my lifetime, its measurement has passed through many stages. When I was born, many physiologists still believed that the lung secreted oxygen. When I was a medical student, the only way we had to recognize defective gas exchange was whether the patient was cyanosed. The advent of the oximeter soon showed that this sign could be very misleading. A breakthrough was the introduction of blood gas electrodes that could measure the PO2 , PCO2 , and pH of a small sample of arterial blood...
October 2018: Physiological Reports
Chase B Hellmer, Melissa Rampino Clemons, Scott Nawy, Tomomi Ichinose
The canonical mGluR6-Trpm1 pathway that generates the sign-inverting signal between photoreceptors and ON bipolar cells has been well described. However, one type of ON bipolar cell, the rod bipolar cell (RBC), additionally is thought to express the group I mGluRs whose function is unknown. We examined the role of group I mGluRs in mouse RBCs and here provide evidence that it controls synaptic gain between rods and RBCs. In dark-adapted conditions, the mGluR1 antagonists LY367385 and (RS)-1-Aminoindan-1,5-dicarboxylic acid, but not the mGluR5 antagonist 2-Methyl-6-(phenylethynyl)pyridine hydrochloride reduced the light-evoked responses in RBCs indicating that mGluR1, but not mGluR5, serves to potentiate RBC responses...
October 2018: Physiological Reports
Takuro Washio, Jennifer R Vranish, Jasdeep Kaur, Benjamin E Young, Keisho Katayama, Paul J Fadel, Shigehiko Ogoh
The mechanism(s) for the increased occurrence of a grayout or blackout, syncope, immediately after heavy resistance exercise are unclear. It is well-known that orthostatic stress increases the occurrence of postexercise syncope. In addition, previous findings have suggested that hypo-perfusion, especially in the posterior cerebral circulation rather than anterior cerebral circulation, may be associated with the occurrence of syncope. Herein, we hypothesized that the postexercise decrease in posterior, but not anterior, cerebral blood flow (CBF) would be greater during orthostatic stress...
October 2018: Physiological Reports
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