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Respiratory Physiology & Neurobiology

Arietta Spinou
Cough can be viewed as a continuum where extremes represent disease phenotypes. Under this unified concept, non-pharmacological treatment for the extremes of the cough spectrum includes both cough augmentation and cough control techniques. Supporting the cough motor output and exercising the cognitive control on coughing are the main directions of these techniques. Cough augmentation can be provided to patients who present low ability to generate adequate peak cough flows, with the aim to develop the sheering forces that are essential for effective airway clearance...
March 9, 2018: Respiratory Physiology & Neurobiology
Tanmay Pal, Pranab Kumar Dutta, Srinivasu Maka
Periodic Breathing (PB) is a diseased condition of the cardiorespiratory system, and mathematically it is modelled as an oscillation. Modeling approaches replicate periodic oscillation in the minute ventilation due to a higher than normal gain of the feedback signals from the chemoreceptors coupled with a longer than normal latency in feedback, and do not consider the waxing-waning pattern of the oronasal airflow. In this work, a noted regulation model is extended by integrating respiratory mechanics and respiratory Central Pattern Generator (rCPG) model, using modulation-demodulation1 hypothesis...
March 8, 2018: Respiratory Physiology & Neurobiology
Ron Dueck, Eric G Wong, G Kim Prisk, Randolph H Hastings
Patients with end-expiratory flow limitation (eEFL) demonstrate a terminal rise in capnography slope. The high slope could represent phase 5, a phenomenon described for single breath N2 tests but previously unreported during capnography. This study evaluated 6 healthy subjects exhaling from total lung capacity to residual volume at several set constant rates. We measured the volumes of flow limitation (VFL ) and phase 5 (VP5 ) for CO2 and N2 . A distinct phase 5 occurred shortly after eEFL for both gases. Increased expiratory flow rate resulted in parallel increases in VFL and VP5 ...
March 8, 2018: Respiratory Physiology & Neurobiology
Stéphanie Conotte, Alexandra Tassin, Raphaël Conotte, Jean-Marie Colet, Karim Zouaoui Boudjeltia, Alexandre Legrand
Chronic intermittent hypoxia (ChIH) is a dominant feature of obstructive sleep apnoea (OSA) and is associated to metabolic alterations and oxidative stress (OS). Although management of OSA is well established, the research of new biomarkers that are independent of confounding factors remains necessary to improve the early detection of comorbidity and therapeutic follow-up. In this study, the urinary metabonomic profile associated to intermittent hypoxia was evaluated in a mouse model. When exposed to intermittent hypoxia, animals showed a significant alteration in energy metabolism towards anaerobic pathways and signs of OS imbalance...
March 6, 2018: Respiratory Physiology & Neurobiology
Z L Rai, H E Fowles, C Wright, H Joseph, A H Morice
INTRODUCTION: Citric acid has been used for over six decades to induce cough; however the mechanism of its pro-tussive effect is still not fully understood. We assessed the response to inhalation of citric acid at varying levels of acidity to determine if the pH of the solution plays a role in the induction of cough. Data was collected from both healthy volunteers and patients with chronic cough. METHODS: 20 chronic cough patients and 20 healthy volunteers were recruited and underwent three cough challenges on separate days...
March 6, 2018: Respiratory Physiology & Neurobiology
Xinguang Cui, Eva Gutheil
An excellent understanding of the airflow properties is critical to improve the drug delivery efficiency via the extrathoracic airway. The present numerical study focuses on the investigation the characteristics of important airflow structures such as the secondary vortices, the impinging jet and the recirculation zone under unsteady inspiration flow conditions in a circular idealized mouth-throat model using large eddy simulation (LES). Five inhalation cycles are simulated, the last one of which is analyzed in detail at five different times...
March 5, 2018: Respiratory Physiology & Neurobiology
Min-Seok Kim, Jin-Young Han, Sung-Hwan Kim, Doin Jeon, Hyeon-Young Kim, Seung Woong Lee, Mun-Chual Rho, Kyuhong Lee
Oleanolic acid acetate (OAA), triterpenoid compound isolated from Vigna angularis (azuki bean), has been revealed anti-inflammatory in several studies. We investigated the effects of OAA against polyhexamethylene guanidine phosphate (PHMG-P)-induced pulmonary inflammation and fibrosis in mice. OAA treatment effectively alleviated PHMG-P-induced lung injury, including the number of total and differential cell in BAL fluid, histopathological lesions and hydroxyproline content in a dose dependent manner. Moreover, OAA treatment significantly decreased the elevations of IL-1β, IL-6, TNF-α, TGF-β1, and fibronectin, and the activation of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in the lungs of PHMG-P-treated mice...
March 2, 2018: Respiratory Physiology & Neurobiology
Kevin McGuinness, Katie Ward, Charles C Reilly, Julie Morris, Jaclyn A Smith
Very few studies have addressed how coughing varies in intensity. We assessed the influence of cough effort and operating volume on the mechanics of coughing using respiratory muscle surface electromyography (EMG), oesophageal/gastric pressures and cough sounds recorded from 15 healthy subjects [8 female, median age 30(IQR 30-50)years] performing 120 voluntary coughs from controlled operating volume/effort and three cough peals. For single coughs, low operating volumes and high efforts were associated with the highest EMG activity (p < 0...
February 27, 2018: Respiratory Physiology & Neurobiology
P S de Campos, L R S M Kawamura, K Hasegawa, Y Kumei, J L Zeredo
Parkinson's disease (PD) is known to cause tremor and rigidity, but other symptoms such as respiratory and autonomic dysfunctions are a major cause of disability and mortality in patients. In this study, we examined respiratory movements by using cineradiography on a murine model of late/advanced PD. Under surgical anesthesia, C57BL/6J mice received an injection of either 6-OHDA or vehicle solution to the right striatum. Two weeks after surgery, the animals had their respiratory movements recorded by video X-ray without any restraint...
February 23, 2018: Respiratory Physiology & Neurobiology
Daniel A Keir, Michael Pollock, Piramilan Thuraisingam, Donald H Paterson, George J F Heigenhauser, Harry B Rossiter, John M Kowalchuk
We examined whether slower pulmonary O2 uptake (V̇O2p ) kinetics in hypoxia is a consequence of: a) hypoxia alone (lowered arterial O2 pressure), b) hyperventilation-induced hypocapnia (lowered arterial CO2 pressure), or c) a combination of both. Eleven participants performed 3-5 repetitions of step-changes in cycle ergometer power output from 20W to 80% lactate threshold in the following conditions: i) normoxia (CON; room air); ii) hypoxia (HX, inspired O2  = 12%; lowered end-tidal O2 pressure [PET O2 ] and end-tidal CO2 pressure [PET CO2 ]); iii) hyperventilation (HV; increased PET O2 and lowered PET CO2 ); and iv) normocapnic hypoxia (NC-HX; lowered PET O2 and PET CO2 matched to CON)...
February 22, 2018: Respiratory Physiology & Neurobiology
Z Kotmanova, M Simera, M Veternik, L Martvon, J Misek, J Jakus, T Y Shen, M N Musselwhite, T Pitts, D C Bolser, I Poliacek
GABA, muscimol, and baclofen were microinjected into the rostral (rNTS) and caudal solitary tract nucleus (cNTS) in 24 anesthetized cats. Electromyograms (EMGs) of diaphragm (DIA) and abdominal muscles (ABD), blood pressure and esophageal pressure (EP) were recorded and analysed. Bilateral microinjections of 1 mM GABA (total 66 ± 4 nl), 1 mM baclofen (64 ± 4 nl) and unilateral microinjections of 0.5 mM muscimol (33 ± 1 nl) in the rNTS significantly reduced cough number (CN), amplitudes of ABD EMGs, expiratory EP, and prolonged the duration of the cough inspiratory phase...
February 20, 2018: Respiratory Physiology & Neurobiology
Ioan Iulia, Demoulin Bruno, Leblanc Anne-Laure, Schweitzer Cyril, Marchal François, Foucaud Laurent, Demoulin-Alexikova Silvia
Lung hyperinflation may alter the pattern of ventilatory reflexes in chronic respiratory disorders. The aim of the study was to test the effect of continuous positive airway pressure (CPAP) on ventilatory responses to mechanical stimulation of the trachea.
February 20, 2018: Respiratory Physiology & Neurobiology
Meihua Sun, Yuanyuan Huang, Feng Li, Haibo Li, Bo Zhang, Lianhua Jin
Pro-inflammatory cytokines-induced airway remodeling was a significant feature of asthma disease. The aim of the present study was to explore the functional significance of miR-874 in tumor necrosis factor (TNF)-α-treated human fetal airway smooth muscle (fASM) cells. Here, we found that TNF-α treatment significantly down-regulated the expression of miR-874 in fASM cells. MiR-874 overexpression markedly inhibited cell viability and migration, suppressed the expression of PCNA and Ki67, reduced the expression of collagen I and collagen III, decreased the expression and activity of matrix metalloproteinase (MMP)-9 and MMP-2, and induced an obvious elevation of tissue inhibitors of metalloproteinases (TIMPs)...
February 12, 2018: Respiratory Physiology & Neurobiology
Mariana Brozmanova, Jan Hanacek
Hyperoxia-induced lung injury is well known in animal and human studies. The respiratory epithelium including sensory nerve endings is a major target for oxidative injury that manifested in lung function changes including cough. On the basis of available information we supposed that hyperoxia alone or in combination with primary lung tissue injury should have a damaging effect on lungs, including the airway nerve endings with the changes in the sensitivity of the central and peripheral neuronal pathways regulating cough...
February 10, 2018: Respiratory Physiology & Neurobiology
Michael G Crooks, Timothy Brown, Alyn H Morice
Chronic obstructive pulmonary disease is predicted to become the 4th leading cause of death worldwide by 2030. The natural history of the disease includes progressive symptoms punctuated by acute exacerbations during which symptoms rapidly deteriorate. The resulting disability places significant burden on health and social care systems. Cough is the second most common symptom reported by COPD patients, is a source of significant distress and is associated with adverse outcomes. We discuss the importance of cough in COPD, its mechanism and the relationship between cough and COPD exacerbations...
February 10, 2018: Respiratory Physiology & Neurobiology
Danny Cantin, Djamal Djeddi, Nathalie Samson, Charlène Nadeau, Jean-Paul Praud
Nasal high-frequency oscillatory ventilation (nHFOV) in neonates is increasingly considered due to enhanced alveolar ventilation, absence of patient-ventilator asynchrony and lessened ventilator-induced lung injury. Although any type of non-invasive respiratory support can lead to gastric distension via esophageal air passage and thus promote gastroesophageal refluxes (GERs), we have shown that nasal continuous positive airway pressure (CPAP; 6 cmH 2 O) and intermittent positive pressure ventilation (15/4 cmH 2 O) conversely inhibit GERs in lambs...
February 10, 2018: Respiratory Physiology & Neurobiology
Ji-Woong Kim, Nguyen Lu Phuong, Shin-Ichiro Aramaki, Kazuhide Ito
Studies concerning inhalation toxicology and respiratory drug-delivery systems require biological testing involving experiments performed on animals. Particle image velocimetry (PIV) is an effective in vitro technique that reveals detailed inhalation flow patterns, thereby assisting analyses of inhalation exposure to various substances. A realistic model of a rhesus-monkey upper airway was developed to investigate flow patterns in its oral and nasal cavities through PIV experiments performed under steady-state constant inhalation conditions at various flow rates-4, 10, and 20 L/min...
February 10, 2018: Respiratory Physiology & Neurobiology
Janos Porszasz, Nicolò Carraro, Robert Cao, Ashwani Gore, Shuyi Ma, Thomas Jiang, François Maltais, Gary T Ferguson, Denis E O'Donnell, Asif Shaikh, Harry B Rossiter, Richard Casaburi
This substudy of a large, randomized, controlled trial (NCT01072396) examined tiotropium (18 μg qd) effects on dynamic hyperinflation during constant work rate treadmill exercise. Areas-under-the-spontaneous expiratory flow-volume (SEFV)-curves were compared in 20 COPD patients and 16 age-matched untreated controls, using rectangular area ratio (RAR) between peak intrabreath and end-expiratory flow. Seven patients exhibited SEFV curve concavity with RAR ≤ 0.5 (RAR low ) in ≥1 test without tiotropium; (mean ± SD FEV 1 : 1...
February 10, 2018: Respiratory Physiology & Neurobiology
Mufaddal I Baghdadwala, Maryana Duchcherer, William M Trask, Paul A Gray, Richard J A Wilson
No abstract text is available yet for this article.
February 8, 2018: Respiratory Physiology & Neurobiology
Kei Hatano, Kazuki Shirakawa, Noboru Usuda, Ryouta Matsuura, Yoshinori Ohtsuka, Takahiro Yunoki
The aim of the present study was to determine the effect of hypercapnia on motor neuromuscular activity of the human triceps surae muscle. Nine subjects participated in trials in a normal breathing condition and a CO2 rebreathing condition. In both conditions, in order to provoke self-sustained muscle activity, percutaneous electrical train stimulation was applied to the tibial nerve while each subject lay on a bed. Self-sustained muscle activity, which is an indirect observation of plateau potentials in spinal motoneurons, was measured for 30 sec after the train stimulation by using surface electromyography...
February 8, 2018: Respiratory Physiology & Neurobiology
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