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https://www.readbyqxmd.com/read/27867486/effects-of-normobaric-versus-hyperbaric-oxygen-on-cell-injury-induced-by-oxygen-and-glucose-deprivation-in-acute-brain-slices
#1
Laurent Chazalviel, Jean-Eric Blatteau, Nicolas Vallée, Jean-Jacques Risso, Stéphane Besnard, Jacques H Abraini
Normobaric oxygen (NBO) and hyperbaric oxygen (HBO) are emerging as a possible co-treatment of acute ischemic stroke. Both have been shown to reduce infarct volume, to improve neurologic outcome, to promote endogenous tissue plasminogen activator-induced thrombolysis and cerebral blood flow, and to improve tissue oxygenation through oxygen diffusion in the ischemic areas, thereby questioning the interest of HBO compared to NBO. In the present study, in order to investigate and compare the oxygen diffusion effects of NBO and HBO on acute ischemic stroke independently of their effects at the vascular level, we used acute brain slices exposed to oxygen and glucose deprivation, an ex vivo model of brain ischemia that allows investigating the acute effects of NBO (partial pressure of oxygen (pO2) = 1 atmospheres absolute (ATA) = 0...
July 2016: Medical Gas Research
https://www.readbyqxmd.com/read/27867482/normobaric-oxygen-treatment-in-acute-ischemic-stroke-a-clinical-perspective
#2
REVIEW
Shu-Hai Shi, Zhi-Feng Qi, Yu-Min Luo, Xun-Ming Ji, Ke Jian Liu
Acute ischemic stroke is a common and serious neurological disease. Oxygen therapy has been shown to increase oxygen supply to ischemic tissues and improve outcomes after cerebral ischemia/reperfusion. Normobaric hyperoxia (NBO), an easily applicable and non-invasive method, shows protective effects on acute ischemic stroke animals and patients in pilot studies. However, many critical scientific questions are still unclear, such as the therapeutic time window of NBO, the long-term effects and the benefits of NBO in large clinic trials...
July 2016: Medical Gas Research
https://www.readbyqxmd.com/read/27867474/nitric-oxide-and-hyperoxic-acute-lung-injury
#3
REVIEW
Wen-Wu Liu, Cui-Hong Han, Pei-Xi Zhang, Juan Zheng, Kan Liu, Xue-Jun Sun
Hyperoxic acute lung injury (HALI) refers to the damage to the lungs secondary to exposure to elevated oxygen partial pressure. HALI has been a concern in clinical practice with the development of deep diving and the use of normobaric as well as hyperbaric oxygen in clinical practice. Although the pathogenesis of HALI has been extensively studied, the findings are still controversial. Nitric oxide (NO) is an intercellular messenger and has been considered as a signaling molecule involved in many physiological and pathological processes...
April 2016: Medical Gas Research
https://www.readbyqxmd.com/read/27867469/hyperbaric-oxygen-increases-tissue-plasminogen-activator-induced-thrombolysis-in-vitro-and-reduces-ischemic-brain-damage-and-edema-in-rats-subjected-to-thromboembolic-brain-ischemia
#4
Laurent Chazalviel, Benoit Haelewyn, Mickael Degoulet, Jean-Eric Blatteau, Nicolas Vallée, Jean-Jacques Risso, Stéphane Besnard, Jacques H Abraini
Recent data have shown that normobaric oxygen (NBO) increases the catalytic and thrombolytic efficiency of recombinant tissue plasminogen activator (rtPA) in vitro, and is as efficient as rtPA at restoring cerebral blood flow in rats subjected to thromboembolic brain ischemia. Therefore, in the present study, we studied the effects of hyperbaric oxygen (HBO) (i) on rtPA-induced thrombolysis in vitro and (ii) in rats subjected to thromboembolic middle cerebral artery occlusion-induced brain ischemia. HBO increases rtPA-induced thrombolysis in vitro to a greater extent than NBO; in addition, HBO treatment of 5-minute duration, but not of 25-minute duration, reduces brain damage and edema in vivo...
April 2016: Medical Gas Research
https://www.readbyqxmd.com/read/27864638/effects-of-caffeine-on-neuromuscular-fatigue-and-performance-during-high-intensity-cycling%C3%A2-exercise-in-moderate-hypoxia
#5
Bruno P C Smirmaul, Antonio Carlos de Moraes, Luca Angius, Samuele M Marcora
PURPOSE: To investigate the effects of caffeine on performance, neuromuscular fatigue and perception of effort during high-intensity cycling exercise in moderate hypoxia. METHODS: Seven adult male participants firstly underwent an incremental exercise test on a cycle ergometer in conditions of acute normobaric hypoxia (fraction inspired oxygen = 0.15) to establish peak power output (PPO). In the following two visits, they performed a time to exhaustion test (78 ± 3% PPO) in the same hypoxic conditions after caffeine ingestion (4 mg kg(-1)) and one after placebo ingestion in a double-blind, randomized, counterbalanced cross-over design...
November 18, 2016: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/27856711/pulmonary-vascular-collagen-content-not-cross-linking-contributes-to-right-ventricular-pulsatile-afterload-and-overload-in-early-pulmonary-hypertension
#6
Zhijie Wang, David A Schreier, Hinnah Abid, Timothy A Hacker, Naomi C Chesler
Hypoxic pulmonary hypertension (HPH) is associated with pulmonary artery (PA) remodeling and right ventricular (RV) overload. We have previously uncovered collagen-mediated mechanisms of proximal PA stiffening in early HPH by manipulating collagen degradation and crosslinking using a transgenic mouse strain and a potent collagen cross-link inhibitor β-aminopropionitrile (BAPN). However, the roles of collagen in distal PA remodeling, overall RV afterload and RV hypertrophy in HPH remain unknown. Here, we used the same experimental strategy to investigate the impact of pulmonary vascular collagen content and cross-linking on steady and pulsatile RV afterload as well as RV hypertrophy in early HPH...
November 17, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27847819/acute-mountain-sickness-symptoms-depend-on-normobaric-versus-hypobaric-hypoxia
#7
Dana M DiPasquale, Gary E Strangman, N Stuart Harris, Stephen R Muza
Acute mountain sickness (AMS), characterized by headache, nausea, fatigue, and dizziness when unacclimatized individuals rapidly ascend to high altitude, is exacerbated by exercise and can be disabling. Although AMS is observed in both normobaric (NH) and hypobaric hypoxia (HH), recent evidence suggests that NH and HH produce different physiological responses. We evaluated whether AMS symptoms were different in NH and HH during the initial stages of exposure and if the assessment tool mattered. Seventy-two 8 h exposures to normobaric normoxia (NN), NH, or HH were experienced by 36 subjects...
2016: BioMed Research International
https://www.readbyqxmd.com/read/27837190/hyperoxia-results-in-increased-aerobic-metabolism-following-acute-brain-injury
#8
Arnab Ghosh, David Highton, Christina Kolyva, Ilias Tachtsidis, Clare E Elwell, Martin Smith
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24-72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy...
November 11, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27826421/cocktail-treatment-a-promising-strategy-to-treat-acute-cerebral-ischemic-stroke
#9
REVIEW
Li-Jun Liang, Jin-Ming Yang, Xin-Chun Jin
Up to now, over 1,000 experimental treatments found in cells and rodents have been difficult to translate to human ischemic stroke. Since ischemia and reperfusion, two separate stages of ischemic stroke, have different pathophysiological mechanisms leading to brain injury, a combination of protective agents targeting ischemia and reperfusion respectively may obtain substantially better results than a single agent. Normobaric hyperoxia (NBO) has been shown to exhibit neuro- and vaso-protective effects by improving tissue oxygenation when it is given during ischemia, however the effect of NBO would diminish when the duration of ischemia and reperfusion was extended...
March 2016: Medical Gas Research
https://www.readbyqxmd.com/read/27810458/effect-of-hyperoxia-on-cerebral-blood-flow-velocity-and-regional-oxygen-saturation-in-patients-operated-upon-for-severe-traumatic-brain-injury-the-influence-of-cerebral-blood-flow-autoregulation
#10
Sarasa Sahoo, Veena Sheshadri, Kamath Sriganesh, K R Madhsudana Reddy, M Radhakrishnan, G S Umamaheswara Rao
BACKGROUND: The effect of normobaric hyperoxia on brain oxygenation in the presence or absence of intact autoregulation has not been studied till now in acute traumatic brain injury (TBI). METHODS: In this prospective clinical investigation in fifty patients operated for severe TBI, cerebral blood flow (CBF) velocity in the middle cerebral artery (MCA) was measured using transcranial doppler (TCD). Regional cerebral oxygen saturation (rSO2) using near infra-red spectroscopy (NIRS) at three different inspired oxygen fractions (FiO2 of 0...
October 31, 2016: World Neurosurgery
https://www.readbyqxmd.com/read/27800505/fifteen-days-of-3-200-m-simulated-hypoxia-marginally-regulates-markers-for-protein-synthesis-and-degradation-in-human-skeletal-muscle
#11
Gommaar D'Hulst, Alessandra Ferri, Damien Naslain, Luc Bertrand, Sandrine Horman, Marc Francaux, David J Bishop, Louise Deldicque
Chronic hypoxia leads to muscle atrophy. The molecular mechanisms responsible for this phenomenon are not well defined in vivo. We sought to determine how chronic hypoxia regulates molecular markers of protein synthesis and degradation in human skeletal muscle and whether these regulations were related to the regulation of the hypoxia-inducible factor (HIF) pathway. Eight young male subjects lived in a normobaric hypoxic hotel (FiO2 14.1%, 3,200 m) for 15 days in well-controlled conditions for nutrition and physical activity...
2016: Hypoxia
https://www.readbyqxmd.com/read/27765844/intermittent-hypobaric-hypoxia-combined-with-aerobic-exercise-improves-muscle-morphofunctional-recovery-after-eccentric-exercise-to-exhaustion-in-trained-rats
#12
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
https://www.readbyqxmd.com/read/27765746/heart-lung-interaction-in-a-model-of-copd-the-importance-of-lung-volume-and-direct-ventricular-interaction
#13
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
https://www.readbyqxmd.com/read/27753502/carbon-monoxide-poisoning-pathogenesis-management-and-future-directions-of-therapy
#14
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
https://www.readbyqxmd.com/read/27750391/clarification-on-altitude-training
#15
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
https://www.readbyqxmd.com/read/27744292/walking-economy-at-simulated-high-altitude-in-human-healthy-young-male-lowlanders
#16
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
https://www.readbyqxmd.com/read/27733362/normobaric-hyperoxia-stimulates-superoxide-and-nitric-oxide-production-in-the-caudal-solitary-complex-of-rat-brain-slices
#17
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
https://www.readbyqxmd.com/read/27729706/effect-of-normobaric-versus-hypobaric-oxygenation-on-gaseous-microemboli-removal-in-a-diffusion-membrane-oxygenator-an-in-vitro-comparison
#18
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
https://www.readbyqxmd.com/read/27721912/effect-of-high-intensity-training-in-normobaric-hypoxia-on-thoroughbred-skeletal-muscle
#19
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
https://www.readbyqxmd.com/read/27708611/a-history-of-mild-traumatic-brain-injury-affects-peripheral-pulse-oximetry-during-normobaric-hypoxia
#20
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
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