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Physiological Reports

Stephen P Fitzgerald, Nigel G Bean
The prevailing teaching regarding homeostasis, and in particular endocrine homeostasis, includes the fundamental concept of a "set point," which represents a target or optimum level defended by physiological control mechanisms. Analogies for the description and teaching of this concept have included thermostats and cruise controls. We previously demonstrated that such a set-point model of regulation implies that in population data of parameter set point/controlling hormone levels, correlations between the parameter and its controlling hormone must be in the direction of the response of the parameter to its controlling hormone, and that in thyroid homeostasis this relationship is not observed...
January 2018: Physiological Reports
Cécyl G Claudel, Waqas Ahmed, Vibeke S Elbrønd, Adrian P Harrison, Else Marie Bartels
This study aimed at looking at the frequency (T-score) and the amplitude (S-score) of fiber use during contraction of a forearm muscle, m. palmaris longus, as measured by acoustic myography (AMG). An additional aim was to relate the T- and S-scores to the recorded force obtained from a hand dynamometer. The hypothesis being that temporal and spatial summation of muscle fiber contraction in a given muscle during a given movement, can together describe a given obtained force. Force measurements were carried out on 12 healthy human subjects aged 19-68 years (6 men & 6 women), while their m...
January 2018: Physiological Reports
Lena Rubi, Hannes Todt, Helmut Kubista, Xaver Koenig, Karlheinz Hilber
Duchenne muscular dystrophy (DMD), caused by mutations in the gene encoding for the cytoskeletal protein dystrophin, is linked with severe cardiac complications including cardiomyopathy development and cardiac arrhythmias. We and others recently reported that currents through L-type calcium (Ca) channels were significantly increased, and channel inactivation was reduced in dystrophin-deficient ventricular cardiomyocytes derived from the mdx mouse, the most commonly used animal model for human DMD. These gain-of-function Ca channel abnormalities may enhance the risk of Ca-dependent arrhythmias and cellular Ca overload in the dystrophic heart...
January 2018: Physiological Reports
Christopher Hazlett, Heather Edgell
Orthostatic intolerance is more common in women than men, and some studies have found that women in the early follicular (EF) phase of the menstrual cycle experience the greatest feelings of lightheadedness. Chemoreflex function while supine or upright was investigated to determine the potential contribution of ventilatory control to these phenomena. Men (n = 13) and women (n = 14) were tested while supine and 70° upright (head-up tilt [HUT]) and given: (1) normoxia or (2) hypercapnia (5% CO2 ). Women were tested during the EF phase (days 2-5) and the midluteal phase (ML; days 18-24)...
January 2018: Physiological Reports
Sienna Kohn, Rowan R Smart, Jennifer M Jakobi
Elbow flexion force depends on forearm orientation with supinated and neutral being stronger than pronated. The purpose of this study was to assess the influence of forearm orientation on voluntary activation (VA), postactivation potentiation (PAP), and twitch properties. Eleven males (23 ± 3 years) performed isometric elbow flexion maximal voluntary contractions (MVC) in supinated, neutral, and pronated forearm orientations with supramaximal stimulation to the biceps brachii muscle belly before, during, and after the MVC...
January 2018: Physiological Reports
Xin-Hua Liu, Rita De Gasperi, William A Bauman, Christopher P Cardozo
Signaling via the androgen receptor (AR) stimulates myogenic progenitor differentiation. In addition, myogenic differentiation factor D (MyoD) and Numb, a Notch inhibitor, play key roles in regulating myogenic differentiation. Nandrolone, an anabolic steroid, upregulates both MyoD and Numb expression in myogenic cells. However, the molecular mechanisms by which MyoD is upregulated by nandrolone are unclear. Moreover, the potential crosstalk between nandrolone, MyoD, and Numb is not well understood. With these considerations in mind, we examined the effects of nandrolone on the expression of MyoD mRNA and protein, and determined the interactions of MyoD and Numb in the presence or absence of nandrolone in differentiating C2C12 myoblasts...
January 2018: Physiological Reports
Neesirg M Patel, Ethan A G Baker, Samuel R Wittman, Isaiah C Engstrom, George H Bourdages, Andrew A McCall, Derek M Miller, Bill J Yates
It is well-documented that feedforward cardiovascular responses occur at the onset of exercise, but it is unclear if such responses are associated with other types of movements. In this study, we tested the hypothesis that feedforward cardiovascular responses occur when a passive (imposed) 60° head-up tilt is anticipated, such that changes in heart rate and carotid artery blood flow (CBF) commence prior to the onset of the rotation. A light cue preceded head-up tilts by 10 sec, and heart rate and CBF were determined for 5-sec time periods prior to and during tilts...
January 2018: Physiological Reports
Andy J King, John P O'Hara, Douglas J Morrison, Tom Preston, Roderick F G J King
This study investigated the effect of carbohydrate (CHO) dose and composition on fuel selection during exercise, specifically exogenous and endogenous (liver and muscle) CHO oxidation. Ten trained males cycled in a double-blind randomized order on 5 occasions at 77% V˙O2max for 2 h, followed by a 30-min time-trial (TT) while ingesting either 60 g·h-1 (LG) or 75 g·h-113 C-glucose (HG), 90 g·h-1 (LGF) or 112.5 g·h-113 C-glucose-13 C-fructose ([2:1] HGF) or placebo. CHO doses met or exceed reported intestinal transporter saturation for glucose and fructose...
January 2018: Physiological Reports
Stefanie Klinger, Patrick Lange, Elisabeth Brandt, Karin Hustedt, Bernd Schröder, Gerhard Breves, Jens Herrmann
Glucose-induced electrogenic ion transport is higher in the porcine ileum compared with the jejunum despite equal apical abundance of SGLT1. The objective of this study was a detailed determination of SGLT1 and GLUT2 expressions at mRNA and protein levels along the porcine small intestinal axis. Phosphorylation of SGLT1 at serine 418 was assessed as a potential modulator of activity. Porcine intestinal tissues taken along the intestinal axis 1 h or 3 h after feeding were analyzed for relative mRNA (RT-PCR) and protein levels (immunoblot) of SGLT1, pSGLT1, GLUT2, (p)AMPK, β2 -receptor, and PKA substrates...
January 2018: Physiological Reports
Susan Wray
No abstract text is available yet for this article.
December 2017: Physiological Reports
Hiromi Honda, Minoru Fujimoto, Satoshi Serada, Hayato Urushima, Takashi Mishima, Hyun Lee, Tomoharu Ohkawara, Nobuoki Kohno, Noboru Hattori, Akihito Yokoyama, Tetsuji Naka
TGF-β has an important role in fibrotic diseases, including idiopathic pulmonary fibrosis (IPF). Detailed analysis of TGF-β signaling in pulmonary fibrosis at the molecular level is needed to identify novel therapeutic targets. Recently, leucine-rich alpha-2 glycoprotein (LRG) was reported to function as a modulator of TGF-β signaling in angiogenesis and tumor progression. However, the involvement of LRG in fibrotic disorders, including IPF, has not yet been investigated. In this study, we investigated the role of LRG in fibrosis by analyzing LRG knockout (KO) mice with bleomycin-induced lung fibrosis, an animal model of pulmonary fibrosis...
December 2017: Physiological Reports
Jasleen K Singh, Varderes Barsegyan, Nikhil Bassi, William Marszalec, Shannon Tai, Shruthi Mothkur, Maaz Mulla, Elsa Nico, Yohannes Shiferaw, Gary L Aistrup, John Andrew Wasserstrom
A highly organized transverse-tubule (TT) system is essential to normal Ca2+ cycling and cardiac function. We explored the relationship between the progressive disruption of TTs and resulting Ca2+ cycling during the development of heart failure (HF). Confocal imaging was used to measure Ca2+ transients and 2-D z-stack images in left ventricular epicardial myocytes of intact hearts from spontaneously hypertensive rats (SHR) and Wistar-Kyoto control rats. TT organization was measured as the organizational index (OI) derived from a fast Fourier transform of TT organization...
December 2017: Physiological Reports
Fei Ma, Dimitrios E Kouzoukas, Katherine L Meyer-Siegler, David E Hunt, Lin Leng, Richard Bucala, Pedro L Vera
Macrophage migration inhibitory factor (MIF) mediates pain although the mechanisms are not well understood. Urothelial activation of protease activated receptor 4 (PAR4) results in urothelial MIF release, urothelial high mobility group box 1 (HMGB1) release and bladder pain in mice without bladder inflammation. All three effects are prevented by MIF inhibition while intravesical disulfide HMGB1 alone can induce bladder pain. This study utilizes genetic MIF deletion to determine whether MIF mediates PAR4-induced bladder pain and is upstream of HMGB1-induced bladder pain...
December 2017: Physiological Reports
Coen C W G Bongers, Mohammad Alsady, Tom Nijenhuis, Yvonne A W Hartman, Thijs M H Eijsvogels, Peter M T Deen, Maria T E Hopman
Exercise may lead to kidney injury through several mechanisms. Urinary Kidney Injury Molecule-1 (uKIM1) and Neutrophil Gelatinase-Associated Lipocalin (uNGAL) are known biomarkers for acute kidney injury, but their response to repetitive exercise remains unknown. We examined the effects of a single versus repetitive bouts of exercise on markers for kidney injury in a middle-aged population. Sixty subjects (aged 29-78 years, 50% male) were included and walked 30, 40 or 50 km for three consecutive days. At baseline and after exercise day 1 and 3, a urine sample was collected to determine uNGAL and uKIM1...
December 2017: Physiological Reports
Pippa J Gunn, Charlotte J Green, Camilla Pramfalk, Leanne Hodson
Human primary hepatocytes are the gold standard for investigating lipid metabolism in nonalcoholic fatty liver disease (NAFLD); however, due to limitations including availability and donor variability, the hepatoma cell lines Huh7 and HepG2 are commonly used. Culturing these cell lines in human serum (HS) has been reported to improve functionality; however, direct comparison of fatty acid (FA) metabolism in response to culturing in HS is lacking. The aim of this study was to compare FA metabolism between HepG2 and Huh7 cells in response to culturing in different sera...
December 2017: Physiological Reports
Subhra Nag, Andrew Resnick
Given the importance of the transcriptional regulator hypoxia-inducible factor-1 (HIF-1) for adaptive hypoxia responses, we examined the effect of stabilized HIF-1α on renal epithelial permeability and directed sodium transport. This study was motivated by histological analysis of cystic kidneys showing increased expression levels of HIF-1α and HIF-2α We hypothesize that compression induced localized ischemia-hypoxia of normal epithelia near a cyst leads to local stabilization of HIF-1α, leading to altered transepithelial transport that encourages cyst expansion...
December 2017: Physiological Reports
Nina Zeng, Randall F D'Souza, Vandre C Figueiredo, James F Markworth, Llion A Roberts, Jonathan M Peake, Cameron J Mitchell, David Cameron-Smith
Sestrins (1, 2, 3) are a family of stress-inducible proteins capable of attenuating oxidative stress, regulating metabolism, and stimulating autophagy. Sequestosome1 (p62) is also a stress-inducible multifunctional protein acting as a signaling hub for oxidative stress and selective autophagy. It is unclear whether Sestrin and p62Ser403 are regulated acutely or chronically by resistance exercise (RE) or training (RT) in human skeletal muscle. Therefore, the acute and chronic effects of RE on Sestrin and p62 in human skeletal muscle were examined through two studies...
December 2017: Physiological Reports
Alexander Jenke, Robert Schur, Carsten Röger, Zehra Karadeniz, Mathias Grüger, Luise Holzhauser, Kostas Savvatis, Wolfgang Poller, Heinz-Peter Schultheiss, Ulf Landmesser, Carsten Skurk
Adiponectin (APN) is a multifunctional adipocytokine that inhibits myocardial fibrosis, dilatation, and left ventricular (LV) dysfunction after myocardial infarction (MI). Coxsackievirus B3 (CVB3) myocarditis is associated with intense extracellular matrix (ECM) remodeling which might progress to dilated cardiomyopathy. Here, we investigated in experimental CVB3 myocarditis whether APN inhibits adverse ECM remodeling following cardiac injury by affecting matrix metalloproteinase (MMP) expression. Cardiac injury was induced by CVB3 infection in APN knockout (APN-KO) and wild-type (WT) mice...
December 2017: Physiological Reports
Guy Trudel, Hans K Uhthoff, Odette Laneuville
Hemoconcentration is observed in bed rest studies, descent from altitude, and exposure to microgravity. Hemoconcentration triggers erythrocyte losses to subsequently normalize erythrocyte concentration. The mechanisms of erythrocyte loss may involve enhanced hemolysis, but has never been measured directly in bed rest studies. Steady-state hemolysis was evaluated by measuring two heme degradation products, endogenous carbon monoxide concentration [CO] and urobilinogen in feces, in 10 healthy men, before, during, and after two campaigns of 21 days of 6° head-down-tilt (HDT) bed rest...
December 2017: Physiological Reports
Muhammad J Ali, Balasekaran Govindasamay, Hoon Kay Hiang, Gerald Seet Gim Lee
This study investigated the physiological difference in recreational runners between a noncontinuous and a continuous endurance training protocol. It also aimed to determine physiological surrogate that could monitor metabolic demand of prolonged running in real-time. For data collection, a total of 18 active male recreational runners were recruited. Physiological (HR, RR, RER, ṼO2, BLa), and overall perceptual (RPEO) responses were recorded against three designed test sessions. Session 1 included ṼO2submax test to determine critical speed (CS) at anaerobic threshold (AT)...
December 2017: Physiological Reports
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