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Respiratory Physiology & Neurobiology

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https://www.readbyqxmd.com/read/29129751/hypoglossal-motoneurons-are-endogenously-activated-by-serotonin-during-the-active-period-of-circadian-cycle
#1
Leszek Kubin, Graziella L Mann
In obstructive sleep apnea patients, contraction of lingual muscles protects the pharyngeal airway from collapse. Hypoglossal (XII) motoneurons innervate the muscles of the tongue and are themselves under wake-related excitatory drives, including that mediated by serotonin (5-HT). Estimates of endogenous 5-HT activation vary among different studies. We tested whether endogenous drive mediated by 5-HT is present in rat XII motoneurons when measured during the active period of the circadian cycle. We monitored sleep-wake states and lingual and nuchal electromyograms (EMGs) while perfusing the XII nucleus with a vehicle or a 5-HT2 receptor antagonist (mianserin, 0...
November 9, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29129750/k-complex-morphological-features-in-male-obstructive-sleep-apnea-hypopnea-syndrome-patients
#2
Lin Sun, Xiangmin Zhang, Shaoxiong Huang, Jiuxing Liang, Yuxi Luo
This study characterized the differences in K-complex (KC) morphology features between obstructive sleep apnea-hypopnea syndrome (OSAHS) patients and healthy controls and analyzed the effect of respiratory events on KC morphology. We enrolled 42 male subjects (21 OSAHS patients and 21 age-matched healthy controls) who underwent overnight polysomnography. KCs in stage N2 were manually identified. We found that KCs in healthy controls had larger negative and whole amplitudes, longer durations, and smoother positive waves than OSAHS patients but smaller positive amplitudes...
November 9, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29128524/numerical-study-of-the-airflow-structures-in-an-idealized-mouth-throat-under-light-and-heavy-breathing-intensities-using-large-eddy-simulation
#3
Xinguang Cui, Wenwang Wu, Eva Gutheil
An excellent understanding of the airflow structures is critical to enhance the efficiency of drug delivery via the human oral airway. The present paper investigates the characteristics of both steady and unsteady airflow structures in an idealized mouth-throat using large eddy simulation (LES). Representative inhalation flow rates of 15L/min at rest and 60L/min in exercise are considered. The study shows that there are more secondary vortices in the pharynx and the laryngeal jet is much longer and more concave in the steady flow field at 15L/min compared to the higher inspiration rate, which decreases the possibility of drug impinging on the wall...
November 8, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29102807/microstructural-cerebral-lesions-are-associated-with-the-severity-of-central-sleep-apnea-with-cheyne-stokes-respiration-in-heart-failure-and-are-modified-by-pap-therapy
#4
Anna Heidbreder, Jens Spießhöfer, Jörg Stypmann, Matthias Boentert, Peter Young, Thomas Duning
This study investigated the association of microstructural cerebral lesions with central sleep apnea with Cheyne-Stokes-respiration (CSA-CSR) in heart failure (HF) patients and the effect of positive airway pressure therapy (PAP) of CSA-CSR on these lesions. PAP-therapy was initiated in patients with HF with midrange and with reduced ejection fraction (NYHA≥II; left ventricular ejection fraction <50%) and proven CSA-CSR. Cerebral magnetic resonance imaging (MRI) scans at 3T including diffusion tensor imaging were obtained before and after 4 months of PAP-therapy...
November 2, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29081358/spinal-activation-of-protein-kinase-c-elicits-phrenic-motor-facilitation
#5
Michael J Devinney, Gordon S Mitchell
The protein kinase C family regulates many cellular functions, including multiple forms of neuroplasticity. The novel PKCθ and atypical PKCζ isoforms have been implicated in distinct forms of spinal, respiratory motor plasticity, including phrenic motor facilitation (pMF) following acute intermittent hypoxia or inactivity, respectively. Although these PKC isoforms are critical in regulating spinal motor plasticity, other isoforms may be important for phrenic motor plasticity. We tested the impact of conventional/novel PKC activator, phorbol 12-myristate 13-acetate (PMA) on pMF...
November 2, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29097171/the-impact-of-intermittent-or-sustained-carbon-dioxide-on-intermittent-hypoxia-initiated-respiratory-plasticity-what-is-the-effect-of-these-combined-stimuli-on-apnea-severity
#6
REVIEW
Jason H Mateika, Gino Panza, Raichel Alex, Mohamad El-Chami
The following review explores the effect that intermittent or sustained hypercapnia coupled to intermittent hypoxia has on respiratory plasticity. The review explores published work which suggests that intermittent hypercapnia leads to long-term depression of respiration when administered in isolation and prevents the initiation of long-term facilitation when administered in combination with intermittent hypoxia. The review also explores the impact that sustained hypercapnia alone and in combination with intermittent hypoxia has on the magnitude of long-term facilitation...
October 30, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29107737/respiratory-functional-and-motor-control-deficits-in-children-with-spinal-cord-injury
#7
Goutam Singh, Andrea L Behrman, Sevda C Aslan, Shelley Trimble, Alexander V Ovechkin
Children with spinal cord injury (SCI) are at high risk for developing complications due to respiratory motor control deficits. However, underlying mechanisms of these abnormalities with respect to age, development, and injury characteristics are unclear. To evaluate the effect of SCI and age on respiratory motor control in children with SCI, we compared pulmonary function and respiratory motor control outcome measures in healthy typically developing (TD) children to age-matched children with chronic SCI. We hypothesized that the deficits in respiratory functional performance in children with SCI are due to the abnormal and age-dependent respiratory muscle activation patterns...
October 28, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29111228/the-effects-of-truncal-adiposity-in-forced-spirometry-sex-differences
#8
Rafael Martín Holguera, Ana Isabel Turrión Nieves, Rosa Rodríguez Torres, María Concepción Alonso
The aim of the current paper is to establish the influence of truncal fat accumulation on the spirometric results of a group of healthy individuals. A cross-sectional study of 305 healthy, non-smoking adult subjects (144 males, 161 females) was conducted. Forced spirometry and dual-energy X-ray absorptiometry to quantify body fat were performed. Partial correlation and multiple linear regression analyses were performed. In females, abdominal fat was negatively correlated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV1)...
October 27, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29074449/intermittent-but-not-sustained-moderate-hypoxia-elicits-long-term-facilitation-of-hypoglossal-motor-output
#9
Julia E R Wilkerson, Michael Devinney, Gordon S Mitchell
Phrenic long-term facilitation (pLTF) is a form of serotonin-dependent respiratory motor plasticity induced by moderate acute intermittent hypoxia (AIH), but not by moderate acute sustained hypoxia (ASH) of similar cumulative duration. Thus, moderate AIH-induced pLTF is sensitive to the pattern of hypoxia. On the other hand, pLTF induced by severe AIH protocols is neither pattern sensitive nor serotonin dependent (it converts to an adenosine-dependent mechanism). Although moderate AIH also induces hypoglossal LTF (hLTF), no data are available concerning its sensitivity/insensitivity to the pattern of hypoxia...
October 23, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29037770/dietary-nitrate-supplementation-opposes-the-elevated-diaphragm-blood-flow-in-chronic-heart-failure-during-submaximal-exercise
#10
Joshua R Smith, Scott K Ferguson, K Sue Hageman, Craig A Harms, David C Poole, Timothy I Musch
Chronic heart failure (CHF) results in a greater cost of breathing and necessitates an elevated diaphragm blood flow (BF). Dietary nitrate (NO3‾) supplementation lowers the cost of exercise. We hypothesized that dietary NO3‾ supplementation would attenuate the CHF-induced greater cost of breathing and thus the heightened diaphragm BF during exercise. CHF rats received either 5days of NO3‾-rich beetroot (BR) juice (CHF+BR, n=10) or a placebo (CHF, n=10). Respiratory muscle BFs (radiolabeled microspheres) were measured at rest and during submaximal exercise (20m/min, 5% grade)...
October 14, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29037769/activation-of-respiratory-muscles-during-respiratory-muscle-training
#11
Stephan Walterspacher, Fabian Pietsch, David Johannes Walker, Kai Röcker, Hans-Joachim Kabitz
It is unknown which respiratory muscles are mainly activated by respiratory muscle training. This study evaluated Inspiratory Pressure Threshold Loading (IPTL), Inspiratory Flow Resistive Loading (IFRL) and Voluntary Isocapnic Hyperpnea (VIH) with regard to electromyographic (EMG) activation of the sternocleidomastoid muscle (SCM), parasternal muscles (PARA) and the diaphragm (DIA) in randomized order. Surface EMG were analyzed at the end of each training session and normalized using the peak EMG recorded during maximum inspiratory maneuvers (Sniff nasal pressure: SnPna, maximal inspiratory mouth occlusion pressure: PImax)...
October 14, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29031573/aerosol-furosemide-for-dyspnea-controlled-delivery-does-not-improve-effectiveness
#12
Capucine Morélot-Panzini, Carl R O'Donnell, Robert W Lansing, Richard M Schwartzstein, Robert B Banzett
Aerosolized furosemide has been shown to relieve dyspnea; nevertheless, all published studies have shown great variability in response. This dyspnea relief is thought to result from the stimulation of slowly adapting pulmonary stretch receptors simulating larger tidal volume. We hypothesized that better control over aerosol administration would produce more consistent dyspnea relief; we used a clinical ventilator to control inspiratory flow and tidal volume. Twelve healthy volunteers inhaled furosemide (40mg) or placebo in a double blind, randomized, crossover study...
October 12, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29024783/oxygen-uptake-kinetics-following-six-weeks-of-interval-and-continuous-endurance-exercise-training-an-explorative-pilot-study
#13
U Drescher, T Schefter, J Koschate, T Schiffer, K Brixius, S Schneider, U Hoffmann
PURPOSE: The aim of the study was to compare the responses of pulmonary (V˙O2pulm) and muscle (V˙O2musc) oxygen uptake kinetics before (PRE) and after (POST) six weeks of endurance exercise training. METHODS: Nine untrained individuals performed pseudo-random binary sequences work rate changes between 30W and 80W at PRE and POST training intervention. Heart rate (HR) and V˙O2pulm were measured beat-to-beat and breath-by-breath, respectively. V˙O2musc was estimated applying the approach of Hoffmann et al...
October 9, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29017972/spirometry-reference-values-for-an-andean-high-altitude-population
#14
Orlando R López Jové, Santiago C Arce, Rene W Chávez, Alejandro Alaniz, Diana Lancellotti, María Nélida Chiapella, Alicia Julián, Eduardo L De Vito, Hernando L Sala
We compared the spirometric values of people living at High Altitude at the Andean Plateau with those predicted for lowland population. RATIONALE: Spirometry reference values are not yet available for the millions of people living at high altitude in the Andean High Plateau. OBJECTIVE: To obtain spirometric prediction equations from a healthy subset of adults living in Argentina at 3440m above sea level. METHODS: We randomly recruited 172 healthy men and 235 healthy women, ages 20-70...
October 7, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28993264/sensory-mechanical-effects-of-a-dual-bronchodilator-and-its-anticholinergic-component-in-copd
#15
Denis E O'Donnell, Amany F Elbehairy, Azmy Faisal, J Alberto Neder, Katherine A Webb
This randomized, double-blind, crossover study examined the physiological rationale for using a dual long-acting bronchodilator (umeclidinium/vilanterol (UME/VIL)) versus its muscarinic-antagonist component (UME) as treatment for dyspnea and exercise intolerance in moderate COPD. After each 4-week treatment period, subjects performed pulmonary function and symptom-limited constant-work rate cycling tests with diaphragm electromyogram (EMGdi), esophageal (Pes), gastric (Pga) and transdiaphragmatic (Pdi) pressure measurements...
October 7, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28993263/angiotensin-1-7-in-the-rostro-ventrolateral-medulla-increases-blood-pressure-and-splanchnic-sympathetic-nerve-activity-in-anesthetized-rats
#16
Mark S Bilodeau, J C Leiter
Angiotensin 1-7 (ANG-(1-7)), a derivative of angiotensin I or II, is involved in the propagation of sympathetic output to the heart and vasculature, and the receptor for ANG-(1-7), the Mas receptor, is expressed on astrocytes in the rostral ventrolateral medulla (RVLM). We recorded blood pressure (BP) and splanchnic sympathetic nerve activity (SSNA) before and after focal injection of ANG-(1-7) into the RVLM of rats. Unilateral injection of ANG-(1-7) into the RVLM, acting through the Mas receptor, increased SSNA and BP, and glutamate receptor antagonists, CNQX and D-AP5, partially reduced the ANG-(1-7) effect...
October 6, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28965822/a-new-method-for-noninvasive-measurement-of-pulmonary-gas-exchange-using-expired-gas
#17
John B West, G Kim Prisk
Measurement of the gas exchange efficiency of the lung is often required in the practice of pulmonary medicine and in other settings. The traditional standard is the values of the PO2, PCO2, and pH of arterial blood. However arterial puncture requires technical expertise, is invasive, uncomfortable for the patient, and expensive. Here we describe how the composition of expired gas can be used in conjunction with pulse oximetry to obtain useful measures of gas exchange efficiency. The new procedure is noninvasive, well tolerated by the patient, and takes only a few minutes...
September 29, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28964937/hypoxia-induces-the-dysfunction-of-human-endothelial-colony-forming-cells-via-hif-1%C3%AE-signaling
#18
Mengyu He, Shuying Ma, Qing Cai, Yan Wu, Chengjie Shao, Hui Kong, Hong Wang, Xiaoning Zeng, Weiping Xie
Endothelial injury is considered as a trigger of pulmonary vascular lesions in the pathogenesis of hypoxic pulmonary hypertension (HPH). Although endothelial colony-forming cells (ECFCs) have vascular regeneration potential to maintain endothelial integrity, hypoxia-induced precise alteration in ECFCs function remains controversial. This study investigated the impact of hypoxia on human ECFCs function in vitro and the underlying mechanism. We found that hypoxia inhibited ECFCs proliferation, migration and angiogenesis...
September 28, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28963087/metformin-influences-on-respiratory-system-in-obese-mice-induced-by-postnatal-overnutrition
#19
Maycon Daniel Dias, Melissa Goulart, Cecilia Dalécio, Silvia Enes-Marques, Évila da Silva Lopes Salles, Marina Venâncio, Elisângela Monteiro Pereira, Valdemar Antonio Paffaro, Erika Kristina Incerpi, Roseli Soncini
Many studies have confirmed the merits of metformin to treat type 2 diabetes, but few studies have addressed its effect on the respiratory system. Moreover, vascular endothelial growth factor (VEGF) is critical to many lung functions. In this way, we evaluated the metformin impact on the lung in treated obese Swiss mice, induced by postnatal overnutrition. Glucose and insulin were detected and the insulin resistance index (HOMA) was calculated; inflammatory cells and nitrite/nitrate concentration (NOx) was quantified from bronchoalveolar lavage, collagen and lung VEGF-a was analysed in the lung tissue and lung mechanics were evaluated by methacholine-induced bronchoconstriction...
September 28, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28963086/developing-an-exogenous-pulmonary-surfactant-glucocorticoids-association-effect-of-corticoid-concentration-on-the-biophysical-properties-of-the-surfactant
#20
Alejandra Cimato, Graciela Facorro, Margarita Martínez Sarrasague
Glucocorticoids (GCs) are used to treat lung disease. GCs incorporated in an exogenous pulmonary surfactant (EPS) could be an alternative management to improve drug delivery avoiding side effects. In the development of these pharmaceutical products, it is important to know the maximum amount of GC that can be incorporated and if increasing quantities of GCs alter EPS biophysical properties. Formulations containing EPS and beclomethasone, budesonide or fluticasone were analyzed (PL 10mg/ml; GC 1-2mg/ml). The microstructure was evaluated by electron paramagnetic resonance spectroscopy, GCs incorporated were determined by UV absorption and polarized light microscopy and surfactant activity with pulsating bubble surfactometer...
September 27, 2017: Respiratory Physiology & Neurobiology
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