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David Rizo-Roca, Juan Gabriel Ríos-Kristjánsson, Cristian Núñez-Espinosa, Estela Santos-Alves, Ines O Goncalves, Jose Magalhaes, Antonio A Ascensao, Teresa Pagès, Ginés Viscor, Joan Ramon Torrella
Unaccustomed eccentric exercise leads to muscle morphological and functional alterations, including microvasculature damage, the repair of which is modulated by hypoxia. Here we present the effects of intermittent hypobaric hypoxia and exercise on recovery from eccentric-induced muscle damage (EEIMD). Soleus muscles from trained rats were excised pre- (CTRL) and 1, 3, 7 and 14 days after a double session of EEIMD protocol. A recovery treatment consisting of one of the following protocols was applied one day after the EEIMD: passive normobaric recovery (PNR), a 4-hour daily exposure to passive hypobaric hypoxia at 4000m (PHR) or hypobaric hypoxia exposure followed by aerobic exercise (AHR)...
October 20, 2016: Journal of Applied Physiology
William Spencer Cheyne, Alexandra Mackenzie Williams, Megan Harper, Neil Derek Eves
COPD is associated with dynamic lung hyperinflation (DH), increased pulmonary vascular resistance (PVR) and large increases in negative intrathoracic pressure (nITP). The individual and interactive effect of these stressors on left ventricular (LV) filling, emptying and geometry, and the role of direct ventricular interaction (DVI) in mediating these interactions have not been fully elucidated. Twenty healthy subjects were exposed to the following stressors alone and in combination: 1) inspiratory resistive loading of -20 cmH2O (nITP), 2) expiratory resistive loading to cause dynamic hyperinflation (DH), and 3) normobaric-hypoxia to increase PVR (hPVR)...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Jason J Rose, Ling Wang, Qinzi Xu, Charles F McTiernan, Sruti Shiva, Jesus Tejero, Mark T Gladwin
Carbon monoxide (CO) poisoning affects 50,000 people a year in the United States. The clinical presentation runs a spectrum, ranging from headache and dizziness to coma and death, with a mortality rate ranging from 1-3%. A significant number of patients who survive CO poisoning suffer from long term neurologic and affective sequelae. The neurologic deficits do not necessarily correlate with blood CO levels, but likely result from the pleiotropic effects of CO on cellular mitochondrial respiration, cellular energy utilization, inflammation and free radical generation, especially in the brain and heart...
October 18, 2016: American Journal of Respiratory and Critical Care Medicine
Grégoire P Millet, Franck Brocherie, Raphael Faiss, Olivier Girard
The authors report that many LHTL studies in normobaric hypoxia (NH) "failed to show a positive outcome", which in our view is only partially true. In a cross-over design, we (Saugy et al. 2016) recently tested if LHTL in hypobaric hypoxia (HH) would lead to larger performance enhancement than in NH. Our hypothesis was that HH (i.e. natural altitude) would lead to larger enhancement than NH but the results were contrary to this hypothesis. So we cannot support the affirmation by Lundby & Robach that "natural altitude remains the best approach"...
October 17, 2016: Experimental Physiology
Masahiro Horiuchi, Yoko Handa, Daijiro Abe, Yoshiyuki Fukuoka
We measured oxygen consumption during walking per unit distance (Cw) values for 12 human healthy young males at six speeds from 0.667 to 1.639 m s(-1) (four min per stage) on a level gradient under normobaric normoxia, moderate hypoxia (15% O2), and severe hypoxia (11% O2). Muscle deoxygenation (HHb) was measured at the vastus lateralis muscle using near-infrared spectroscopy. Economical speed which can minimize the Cw in each individual was calculated from a U-shaped relationship. We found a significantly slower economical speed (ES) under severe hypoxia [1...
October 15, 2016: Biology Open
Geoffrey E Ciarlone, Jay B Dean
Central CO2 chemosensitive neurons in the caudal solitary complex (cSC) are stimulated not only by hypercapnic acidosis (HA), but by hyperoxia as well. While a cellular mechanism for the CO2 response has yet to be isolated, previous data show that a redox-sensitive mechanism underlies neuronal excitability to hyperoxia. However, it remains unknown how changes in pO2 affect the production of reactive oxygen and nitrogen species (RONS) in the cSC that can lead to increased cellular excitability and with larger doses, cellular dysfunction and death...
October 12, 2016: American Journal of Physiology. Cell Physiology
Matthew Schuldes, Jeffrey B Riley, Stephen G Francis, Sean Clingan
Gaseous microemboli (GME) are an abnormal physiological occurrence during cardiopulmonary bypass and extracorporeal membrane oxygenation (ECMO). Several studies have correlated negative sequelae with exposure to increased amounts of GME. Hypobaric oxygenation is effective at eliminating GME in hollow-fiber microporous membrane oxygenators. However, hollow-fiber diffusion membrane oxygenators, which are commonly used for ECMO, have yet to be validated. The purpose of this study was to determine if hypobaric oxygenation, compared against normobaric oxygenation, can reduce introduced GME when used on diffusion membrane oxygenators...
September 2016: Journal of Extra-corporeal Technology
Hiroshi Nagahisa, Kazutaka Mukai, Hajime Ohmura, Toshiyuki Takahashi, Hirofumi Miyata
Hypoxic training is believed to increase endurance capacity in association with hypoxia inducible factor-1α (HIF-1α), a modulator of vascular endothelial growth factor-A (VEGF-A), and to influence activation of satellite cells (SCs). However, the effect of hypoxic training on SC activation and its relation to angiogenesis has not been thoroughly investigated. Eight Thoroughbred horses were subjected to normoxic (FIO2 = 21%) or hypoxic (FIO2 = 15%) training for 3 days/week (100%  [Formula: see text]) for 4 weeks...
2016: Oxidative Medicine and Cellular Longevity
Leonard A Temme, Paul St Onge, Joseph Bleiberg
INTRODUCTION: Physiological and emotional stressors increase symptoms of concussion in recently injured individuals and both forms of stress-induced symptoms in people recovering from mild traumatic brain injury (mTBI), but who are asymptomatic when not stressed or are at rest. METHODS: Healthy asymptomatic adults (25.0 ± 5.1 years) with a history of mTBI (n = 36) and matched healthy controls (HC) (n = 36) with no mTBI history were exposed to three levels of normobaric hypoxic stress generated with the Reduced Oxygen Breathing Device (ROBD) (Environics, Inc...
2016: Frontiers in Neurology
Mathew J Wong, Crystal Kantores, Julijana Ivanovska, Amish Jain, Robert P Jankov
Chronic neonatal pulmonary hypertension (PHT) frequently results in early death. Systemically administered Rho-kinase (ROCK) inhibitors prevent and reverse chronic PHT in neonatal rats, but at the cost of severe adverse effects, including systemic hypotension and growth restriction. Simvastatin has pleiotropic inhibitory effects on isoprenoid intermediates that may limit activity of RhoA, which signals upstream of ROCK. We therefore hypothesized that statin treatment would safely limit pulmonary vascular RhoA activity and prevent and reverse experimental chronic neonatal PHT via downstream inhibitory effects on pathological ROCK activity...
September 30, 2016: American Journal of Physiology. Lung Cellular and Molecular Physiology
Dale R Wagner, Skyler Saunders, Brady Robertson, John E Davis
: Wagner, Dale R., Skyler Saunders, Brady Robertson, and John E. Davis. Normobaric hypoxia effects on balance measured by computerized dynamic posturography. High Alt Med Biol. 17:222-227, 2016.-Background/Aim: Equilibrium was measured by computerized dynamic posturography at varying levels of normobaric hypoxia before and after exercise. METHODS: Following a familiarization trial, 12 males (27.3 ± 7.1 years) completed three sessions in random order on a NeuroCom SMART Balance Master: a sham trial at the ambient altitude of 1500 m and simulated altitudes of 3000 and 5000 m created by a hypoxic generator...
September 2016: High Altitude Medicine & Biology
Taner Ozgurtas, Sercan Tekin, Fatih Yesildal, Umut Karaca, Fevzi Nuri Aydin, Muhammed Talha Ugurlu, Mehmet Ozler, Hakan Durukan
AIM: To examine changes in retinal vasculature after treatment with different oxygen concentrations from common retinopathy of prematurity (ROP) models and to determine a novel and practical ROP model. METHODS: A sample of 14 newborn Sprague-Dawley rats was used. The study group (n=7) was exposed to 95% oxygen for 4h per day followed by normoxic laboratory conditions for 20h. This cycle was repeated for 14d. The control group (n=7) was subjected to normobaric normoxic conditions...
2016: International Journal of Ophthalmology
Chen Yao, Gang Li, Yeyong Qian, Ming Cai, Hong Yin, Li Xiao, Wei Tang, Fengjie Guo, Bingyi Shi
To investigate the effect of pentoxifylline (PTX) on spermatogenesis dysfunction induced by intermittent hypobaric hypoxia (IHH) and unveil the underlying mechanism, experimental animals were assigned to Control, IHH+Vehicle, and IHH+PTX groups and exposed to 4 cycles of 96 h of hypobaric hypoxia followed by 96 h of normobaric normoxia for 32 days. PTX was administered for 32 days. Blood and tissue samples were collected 7 days thereafter. Serum malondialdehyde levels were used to assess lipid peroxidation; ferric-reducing antioxidant power (FRAP), superoxide dismutase, and catalase and glutathione peroxidase enzyme activities were assessed to determine antioxidant capacity in various samples...
2016: Oxidative Medicine and Cellular Longevity
Taku Tanaka, Takeshi Kashimura, Marii Ise, Brandon D Lohman, Yasuhiko Taira
BACKGROUND: Because treatment modalities for carbon monoxide (CO) poisoning, especially normobaric oxygen and hyperbaric oxygen therapies, have limited effects and hyperbaric oxygen is not available at the scene where treatment is most needed, we conducted a study to determine and compare rates of carboxyhemoglobin (COHb) dissociation achieved in human in vitro blood samples under light radiation emitted at three levels of illuminance. This was done with a view toward eventual on-site application...
2016: Journal of Intensive Care
Shane A Bielko, Allison J Campbell, Chad C Wiggins, Timothy D Mickleborough, Robert F Chapman
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Pinar Ulker
: Backround:Possible toxic effects of hyperoxia have been reported previously. However, the number of studies investigating the influence of hyperoxia on blood cells is limited and there are no data regarding its hemorheological effects. OBJECTIVE: The aim of this study was to investigate the effects of acute hyperoxia, performed in human subjects at normal atmospheric pressure, on the rheological properties of blood. METHOD: The study was conducted with 12 brain death patients mechanically ventilated in the intensive care unit...
August 10, 2016: Biorheology
Oliver Michael Shannon, Lauren Duckworth, Matthew John Barlow, David Woods, Jose Lara, Mario Siervo, John Paul O'Hara
Nitrate-rich beetroot juice (BRJ) increases plasma nitrite concentrations, lowers the oxygen cost (V⋅O2) of steady-state exercise and improves exercise performance in sedentary and moderately-trained, but rarely in well-trained individuals exercising at sea-level. BRJ supplementation may be more effective in a hypoxic environment, where the reduction of nitrite into nitric oxide (NO) is potentiated, such that well-trained and less well-trained individuals may derive a similar ergogenic effect. We conducted a randomised, counterbalanced, double-blind placebo controlled trial to determine the effects of BRJ on treadmill running performance in moderate normobaric hypoxia (equivalent to 2500 m altitude) in participants with a range of aerobic fitness levels...
September 30, 2016: Nitric Oxide: Biology and Chemistry
Hwang-Woon Moon, Sub Sunoo, Hun-Young Park, Dong-Jun Lee, Sang-Seok Nam
PURPOSE: Evaluation of metabolic parameters and cardiac function is important to determine the decrease in aerobic exercise capacity under hypoxic conditions. However, the variations in metabolic parameters and cardiac function and the reasons for the decrease in aerobic exercise capacity under hypoxic conditions have not been clearly explained. The purpose of this study was to compare the responses between sea level and various acute normobaric hypoxic conditions on metabolic parameters and cardiac function during exercise and recovery in order to evaluate aerobic exercise capacity...
2016: SpringerPlus
Alan J Richardson, Rebecca L Relf, Arron Saunders, Oliver R Gibson
Sprint interval training (SIT) is an efficient intervention capable of improving aerobic capacity and exercise performance. This experiment aimed to determine differences in training adaptations and the inflammatory responses following 2 weeks of SIT (30 s maximal work, 4 min recovery; 4-7 repetitions) performed in normoxia or hypoxia. Forty-two untrained participants [(mean ± SD), age 21 ±1 years, body mass 72.1 ±11.4 kg, and height 173 ±10 cm] were equally and randomly assigned to one of three groups; control (CONT; no training, n = 14), normoxic (NORM; SIT in FiO2: 0...
2016: Frontiers in Physiology
Mohammad Pakravan, Nasrin Sanjari, Hamed Esfandiari, Parastou Pakravan, Mehdi Yaseri
BACKGROUND: To evaluate the effect of high-dose intravenous steroids, as well as normobaric oxygen therapy, in the management of recent onset non-arteritic anterior ischemic optic neuropathy (NAION). METHOD: Ninety eyes of 90 patients diagnosed with NAION within 14 days of onset were included in this single masked randomized clinical trial. Thirty patients were randomized into each set as group 1 (control), group 2 (steroids), and group 3 (oxygen). Controls received placebo; group 2 received methylprednisolone 500 mg twice a day for 3 days followed by 2 weeks of oral prednisolone 1 mg/kg/day; group 3 received 100 % normobaric oxygen with mask, at a flow rate of 5 liters per minute for 1 hour twice a day for two weeks...
October 2016: Graefe's Archive for Clinical and Experimental Ophthalmology
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