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acute intermittent hypoxia

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https://www.readbyqxmd.com/read/28620058/intermittent-hypercapnic-hypoxia-during-sleep-does-not-induce-ventilatory-long-term-facilitation-in-healthy-males
#1
Naomi Louise Deacon, Doug R McEvoy, Daniel L Stadler, Peter G Catcheside
Intermittent hypoxia induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO2 levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus, the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans...
June 15, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28592693/non-genomic-actions-of-17-%C3%AE-estradiol-restore-respiratory-neuroplasticity-in-young-ovariectomized-female-rats
#2
Brendan J Dougherty, Elizabeth S Kopp, Jyoti J Watters
Gonadal steroids modulate CNS plasticity, including phrenic long-term facilitation (pLTF), a form of spinal respiratory neuroplasticity resulting in increased phrenic nerve motor output following exposure to acute intermittent hypoxia (aIH; three 5 min episodes, 10.5% O2). Despite the importance of respiratory system neuroplasticity, and its dependence on estrogen in males, little is known about pLTF expression or mechanisms of estrogen signaling in females. Here, we tested the hypotheses that: 1) pLTF expression in young, gonadally intact female rats would be expressed during estrous cycle stages in which 17β-estradiol (E2) is naturally high (e...
June 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28585890/hypoxic-conditioning-and-the-central-nervous-system-a-new-therapeutic-opportunity-for-brain-and-spinal-cord-injuries
#3
S Baillieul, S Chacaroun, S Doutreleau, O Detante, J L Pépin, S Verges
Central nervous system diseases are among the most disabling in the world. Neuroprotection and brain recovery from either acute or chronic neurodegeneration still represent a challenge in neurology and neurorehabilitation as pharmacology treatments are often insufficiently effective. Conditioning the central nervous system has been proposed as a potential non-pharmacological neuro-therapeutic. Conditioning refers to a procedure by which a potentially deleterious stimulus is applied near to but below the threshold of damage to the organism to increase resistance to the same or even different noxious stimuli given above the threshold of damage...
June 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28567018/acute-normobaric-hypoxia-increases-post-exercise-lipid-oxidation-in-healthy-males
#4
Liam P Kelly, Fabien A Basset
The primary objective of the current study was to determine the effect of moderate normobaric hypoxia exposure during constant load cycling on post-exercise energy metabolism recorded in normoxia. Indirect calorimetry was used to examine whole body substrate oxidation before, during, 40-60 min post, and 22 h after performing 60 min of cycling exercise at two different fractions of inspired oxygen (FIO2): (i) FIO2 = 0.2091 (normoxia) and (ii) FIO2 = 0.15 (hypoxia). Seven active healthy male participants (26 ± 4 years of age) completed both experimental trials in randomized order with a 7-day washout period to avoid carryover effects between conditions...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28549897/daily-acute-intermittent-hypoxia-improves-breathing-function-with-acute-and-chronic-spinal-injury-via-distinct-mechanisms
#5
B J Dougherty, J Terada, S R Springborn, S Vinit, P M MacFarlane, G S Mitchell
Daily acute intermittent hypoxia (dAIH) elicits respiratory plasticity, enhancing respiratory motor output and restoring breathing capacity after incomplete cervical spinal injuries (cSCI). We hypothesized that dAIH-induced functional recovery of breathing capacity would occur after both acute (2 weeks) and chronic (8 weeks) cSCI, but through distinct cellular mechanisms. Specifically, we hypothesized that dAIH-induced breathing recovery would occur through serotonin-independent mechanisms 2wks post C2 cervical hemisection (C2Hs), versus serotonin-dependent mechanisms 8wks post C2Hs...
May 24, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28522758/regulation-of-erythropoiesis-after-normoxic-return-from-chronic-sustained-and-intermittent-hypoxia
#6
Jihyun Song, Krishna Sundar, Radhika Gangaraju, Josef T Prchal
Hypoxia increases erythropoiesis mediated by hypoxia-inducible transcription factors (HIF) which regulate erythropoietin (EPO) transcription. Neocytolysis is a physiological mechanism that corrects polycythemia from chronic sustained hypoxemia (CSH) by transient, preferential destruction of young RBCs after normoxia is restored. We showed that neocytolysis is caused by excessive mitochondrial-derived reactive oxygen species (ROS) in reticulocytes mediated by down-regulation of HIF-controlled BNIP3L regulated mitophagy and a decrease in RBC antioxidant catalase (CAT) in hypoxia-produced erythrocytes...
May 18, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28506824/hypoxia-and-nicotine-effects-on-pituitary-adenylate-cyclase-activating-polypeptide-pacap-and-its-receptor-1-pac1-in-the-developing-piglet-brainstem
#7
J Huang, K A Waters, R Machaalani
Pituitary adenylate cyclase activating polypeptide (PACAP) and its cognate receptor 1 (PAC1), have been implicated in the pathophysiology of the Sudden Infant Death Syndrome (SIDS). Two main risk factors for SIDS are prone sleeping and cigarette smoke exposure. Using piglet models of these risk factors, intermittent hypercapnic hypoxia (IHH-mimicking rebreathing in prone position) and nicotine (main reinforcing element of cigarettes), this study aimed to determine their effects on PACAP and PAC1 protein expression in the medulla...
May 12, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28500219/mechanisms-of-enhanced-phrenic-long-term-facilitation-in-sod1-g93a-rats
#8
Nicole L Nichols, Irawan Satriotomo, Latoya L Allen, Ashley M Grebe, Gordon S Mitchell
Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease, causing muscle paralysis and death from respiratory failure. Effective means to preserve/restore ventilation are necessary to increase the quality and duration of life in ALS patients. At disease end-stage in a rat ALS model (SOD1(G93A) ), acute intermittent hypoxia (AIH) restores phrenic nerve activity to normal levels via enhanced phrenic long-term facilitation (pLTF). Mechanisms enhancing pLTF in end-stage SOD1(G93A) rats are not known...
June 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28483998/hypoxia-treatment-reverses-neurodegenerative-disease-in-a-mouse-model-of-leigh-syndrome
#9
Michele Ferrari, Isha H Jain, Olga Goldberger, Emanuele Rezoagli, Robrecht Thoonen, Kai-Hung Chen, David E Sosnovik, Marielle Scherrer-Crosbie, Vamsi K Mootha, Warren M Zapol
The most common pediatric mitochondrial disease is Leigh syndrome, an episodic, subacute neurodegeneration that can lead to death within the first few years of life, for which there are no proven general therapies. Mice lacking the complex I subunit, Ndufs4, develop a fatal progressive encephalopathy resembling Leigh syndrome and die at ≈60 d of age. We previously reported that continuously breathing normobaric 11% O2 from an early age prevents neurological disease and dramatically improves survival in these mice...
May 23, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28464406/sustained-apnea-induces-endothelial-activation
#10
Lars Eichhorn, Ramona Dolscheid-Pommerich, Felix Erdfelder, Muhammad Ajmal Ayub, Theresa Schmitz, Nikos Werner, Felix Jansen
BACKGROUND: Apnea diving has gained worldwide popularity, even though the pathophysiological consequences of this challenging sport on the human body are poorly investigated and understood. This study aims to assess the influence of sustained apnea in healthy volunteers on circulating microparticles (MPs) and microRNAs (miRs), which are established biomarkers reflecting vascular function. HYPOTHESIS: Short intermittent hypoxia due to voluntary breath-holding affects circulating levels of endothelial cell-derived MPs (EMPs) and endothelial cell-derived miRs...
May 2, 2017: Clinical Cardiology
https://www.readbyqxmd.com/read/28459156/antioxidant-tempol-suppresses-heart-cytosolic-phospholipase-a2%C3%AE-stimulated-by-chronic-intermittent-hypoxia
#11
Petra Míčová, Martina Klevstig, Kristýna Holzerová, Marek Vecka, Jitka Žurmanová, Jan Neckář, František Kolář, Olga Nováková, Jiří Novotný, Markéta Hlaváčková
Adaptation to chronic intermittent hypoxia (CIH) is associated with reactive oxygen species (ROS) generation implicated in the improved cardiac tolerance against acute ischemia-reperfusion injury. Phospholipases A2 (PLA2s) play an important role in cardiomyocyte phospholipid metabolism influencing membrane homeostasis. Here we aimed to determine the effect of CIH (7000 m, 8 h/day, 5 weeks) on the expression of cytosolic PLA2 (cPLA2α), its phosphorylated form (p-cPLA2α), calcium-independent (iPLA2), and secretory (sPLA2IIA) at protein and mRNA levels, as well as fatty acids (FA) profile in left ventricular myocardium of adult male Wistar rats...
April 30, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28451849/role-of-carotid-body-in-intermittent-hypoxia-related-hypertension
#12
REVIEW
Rodrigo Iturriaga, María Paz Oyarce, Ana Carolina Rodrigues Dias
Obstructive sleep apnea (OSA), a common breathing disorder, is recognized as an independent risk factor for systemic hypertension. Among the alterations induced by OSA, the chronic intermittent hypoxia (CIH) is considered the main factor for the hypertension. Exposure of rodents to CIH is the gold-standard method to study the mechanisms involved in the cardiovascular alterations induced by OSA. Although it is well known that CIH produces hypertension, the underlying mechanisms are not totally elucidated. It is likely that the CIH-induced systemic oxidative stress and inflammation may elicit endothelial dysfunction and increase the arterial blood pressure...
May 2017: Current Hypertension Reports
https://www.readbyqxmd.com/read/28413125/transient-dysautonomia-in-an-acute-phase-of-encephalopathy-with-biphasic-seizures-and-late-reduced-diffusion
#13
Yuko Ichimiya, Noriyuki Kaku, Yasunari Sakai, Fumiya Yamashita, Wakato Matsuoka, Mamoru Muraoka, Satoshi Akamine, Soichi Mizuguchi, Michiko Torio, Yoshitomo Motomura, Yuichiro Hirata, Yoshito Ishizaki, Masafumi Sanefuji, Hiroyuki Torisu, Hidetoshi Takada, Yoshihiko Maehara, Shouichi Ohga
Paroxysmal sympathetic hyperactivity (PSH) is a dysautonomic condition that is associated with various types of acquired brain injuries. Traumatic brain lesions have been documented as the leading cause of PSH. However, detailed clinical features of pediatric PSH caused by intrinsic brain lesions remain to be elusive. We present a 3-year-old boy, who had been diagnosed as having cerebral palsy, developmental delay and epilepsy after perinatal hypoxia-induced brain injury. He developed status epilepticus with fever on the third day of respiratory infection...
April 13, 2017: Brain & Development
https://www.readbyqxmd.com/read/28386237/prediction-of-critical-power-and-w-in-hypoxia-application-to-work-balance-modelling
#14
Nathan E Townsend, David S Nichols, Philip F Skiba, Sebastien Racinais, Julien D Périard
Purpose: Develop a prediction equation for critical power (CP) and work above CP (W') in hypoxia for use in the work-balance ([Formula: see text]) model. Methods: Nine trained male cyclists completed cycling time trials (TT; 12, 7, and 3 min) to determine CP and W' at five altitudes (250, 1,250, 2,250, 3,250, and 4,250 m). Least squares regression was used to predict CP and W' at altitude. A high-intensity intermittent test (HIIT) was performed at 250 and 2,250 m. Actual and predicted CP and W' were used to compute W' during HIIT using differential ([Formula: see text]) and integral ([Formula: see text]) forms of the [Formula: see text] model...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28332435/mild-acute-intermittent-hypoxia-improves-respiratory-function-in-unanesthetized-rats-with-midcervical-contusion
#15
Kun-Ze Lee, Shu-Chi Chiang, Yu-Jie Li
BACKGROUND: Mild intermittent hypoxia has been considered a potential approach to induce respiratory neuroplasticity. OBJECTIVE: The purpose of the present study was to investigate whether mild acute intermittent hypoxia can improve breathing function in a clinically relevant spinal cord injury animal model. METHODS: Adult male rats received laminectomy or unilateral contusion at the C3-C4 spinal cord using a MASCIS Impactor (height: 6.25 or 12...
April 2017: Neurorehabilitation and Neural Repair
https://www.readbyqxmd.com/read/28238671/cardiac-autonomic-ganglia-ablation-suppresses-atrial-fibrillation-in-a-canine-model-of-acute-intermittent-hypoxia
#16
Xiaomei Yu, Zhibing Lu, Wenbo He, Bo He, Ruisong Ma, Jing Xie, Hong Jiang
BACKGROUND: Atrial fibrillation (AF) is associated with hypoxia in which cardiac autonomic nerve system (ANS) plays an important role. Our previous studies indicated that ANS is activated in an intermittent hypoxia model and contributes to AF initiation. This study aimed to investigate the effects of cardiac ganglionated plexus (GP) ablation on AF in this model. METHODS AND RESULTS: In thirteen anesthetized male dogs, GP ablation was applied after 1h of intermittent hypoxia in the first group (n=7) and before that in the second group (n=6)...
February 23, 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28235547/intermittent-hypercapnic-hypoxia-effects-on-the-nicotinic-acetylcholine-receptors-in-the-developing-piglet-hippocampus-and-brainstem
#17
Arunnjah Vivekanandarajah, Atqiya Aishah, Karen A Waters, Rita Machaalani
This study investigated the effects of acute (1 day) vs repeated (4 days) exposure to intermittent hypercapnic hypoxia (IHH) on the immunohistochemical expression of α2, α3, α5, α7, α9 and β2 nicotinic acetylcholine receptor (nAChR) subunits in the developing piglet hippocampus and brainstem medulla, and how prior nicotine exposure alters the response to acute IHH. Five piglet groups included: 1day IHH (1D IHH, n=9), 4days IHH (4D IHH, n=8), controls exposed only to air cycles for 1day (1D Air, n=6) or 4days (4D Air, n=5), and pre-exposed to nicotine for 13days prior to 1day IHH (Nic+1D IHH, n=7)...
February 22, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28167915/the-role-of-acute-intermittent-hypoxia-in-neutrophil-generated-superoxide-sympathovagal-balance-and-vascular-function-in-healthy-subjects
#18
Germana P L Almeida, Ivani C Trombetta, Felipe X Cepeda, Elaine Hatanaka, Rui Curi, Cristiano Mostarda, Maria C Irigoyen, José A S Barreto-Filho, Eduardo M Krieger, Fernanda M Consolim-Colombo
Introduction: Recurrent hypoxia (HPX), a hallmark of the obstructive sleep apnea (OSA), impairs autonomic balance, and increases arterial blood pressure (BP). Oxidative stress is one of the mechanisms involved in these alterations. The cumulative effect of acute intermittent HPX and the chronicity may determine whether the response crosses the threshold from having protective value to pathology. However, the impact of acute intermittent HPX-reoxygenation on markers of oxidative stress in healthy individuals remains to be fully understood...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28087818/three-hours-of-intermittent-hypoxia-increases-circulating-glucose-levels-in-healthy-adults
#19
Lauren P Newhouse, Michael J Joyner, Timothy B Curry, Marcello C Laurenti, Chiara Dalla Man, Claudio Cobelli, Adrian Vella, Jacqueline K Limberg
An independent association exists between sleep apnea and diabetes. Animal models suggest exposure to intermittent hypoxia, a consequence of sleep apnea, results in altered glucose metabolism and fasting hyperglycemia. However, it is unknown if acute exposure to intermittent hypoxia increases glucose concentrations in nondiabetic humans. We hypothesized plasma glucose would be increased from baseline following 3 h of intermittent hypoxia in healthy humans independent of any effect on insulin sensitivity. Eight (7M/1F, 21-34 years) healthy subjects completed two study visits randomized to 3 h of intermittent hypoxia or continuous normoxia, followed by an oral glucose tolerance test...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28068279/identifying-predictors-of-central-sleep-apnea-cheyne-stokes-breathing-in-chronic-heart-failure-a-pathophysiological-approach
#20
REVIEW
Aneliya I Draganova, Kiril V Terziyski, Stefan S Kostianev
Chronic heart failure (CHF) is a major health problem associated with increased mortality, despite modern treatment options. Central sleep apnea (CSA)/Cheyne-Stokes breathing (CSB) is a common and yet largely under-diagnosed co-morbidity, adding significantly to the poor prognosis in CHF because of a number of acute and chronic effects, including intermittent hypoxia, sympathetic overactivation, disturbed sleep architecture and impaired physical tolerance. It is characterized by repetitive periods of crescendo-decrescendo ventilatory pattern, alternating with central apneas and hypopneas...
December 1, 2016: Folia Medica
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