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Respiratory Physiology & Neurobiology

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https://www.readbyqxmd.com/read/28330778/intratracheal-lps-administration-attenuates-the-acute-hypoxic-ventilatory-response-role-of-brainstem-il-1%C3%AE-receptors
#1
A P Ribeiro, C A Mayer, C G Wilson, R J Martin, P M MacFarlane
Perinatal inflammation and infection are commonly associated with various respiratory morbidities in preterm infants including apnea of prematurity. In this study, we investigated whether pulmonary inflammation via intra-tracheal micro-injection of lipopolysaccharide (LPS) into neonatal rats modifies respiratory neural control via an IL-1β receptor-dependent mechanism. Prior to an intra-tracheal micro-injection of LPS (1mg/kg), 10day old (Postnatal age, P10) rats received an intraperitoneal (i.p.) or intracisternal (i...
March 19, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28323205/modelling-mixing-within-the-dead-space-of-the-lung-improves-predictions-of-functional-residual-capacity
#2
Chris D Harrison, Phi Anh Phan, Cathy Zhang, Daniel Geer, Andrew D Farmery, Stephen J Payne
Routine estimation of functional residual capacity (FRC) in ventilated patients has been a long held goal, with many methods previously proposed, but none have been used in routine clinical practice. This paper proposes three models for determining FRC using the nitrous oxide concentration from the entire expired breath in order to improve the precision of the estimate. Of the three models proposed, a dead space with two mixing compartments provided the best results, reducing the mean limits of agreement with the FRC measured by whole body plethysmography by up to 41%...
March 18, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28323204/nitric-oxide-uptake-in-the-lung-it-is-about-time-that-clinicians-use-this-test-routinely
#3
EDITORIAL
Gerald S Zavorsky
No abstract text is available yet for this article.
March 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28323203/the-association-between-cardiorespiratory-fitness-and-pulmonary-diffusing-capacity
#4
Gerald S Zavorsky, James M Smoliga
Pulmonary diffusing capacity for nitric oxide (DL,NO) and carbon monoxide (DL,CO) measured at rest (mL/min/mmHg) is strongly associated with aerobic capacity (cardiorespiratory fitness or peak oxygen uptake, VO2peak) measured in L/min. Data from healthy, non-obese individuals from various studies (n=121 males and 81 females) were combined to examine this association. Subjects that were above the upper limit of normal (ULN, 97.5th percentile for age and sex and height) for DL,NO and DLCO had a higher median VO2peak compared to subjects below the ULN (Above the ULN=4...
March 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28300726/a-computational-comparison-of-the-multiple-breath-washout-and-forced-oscillation-technique-as-markers-of-bronchoconstriction
#5
Brody H Foy, David Kay
Many types of lung disease lead to constriction of airways within the conducting zone, causing increases in airway resistance and ventilation heterogeneity (VH). The multiple-breath washout (MBW) and forced oscillation technique (FOT) are two clinical measures of small airway bronchoconstriction. Within this study computational modelling of the MBW and FOT was applied to the analysis of thousands of bronchoconstriction scenarios in the conducting zone of the lungs. The simulations show that MBW indices primarily respond to the severity of constriction, while FOT indices may be able to distinguish between constrictions at differing airway depths...
March 12, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28288844/forced-vital-capacity-and-not-central-chemoreflex-predicts-maximal-hyperoxic-breath-hold-duration-in-elite-apneists
#6
Anthony R Bain, Otto F Barak, Ryan L Hoiland, Ivan Drvis, Damian M Bailey, Zeljko Dujic, Tanja Mijacika, Antoinette Santoro, Daniel K DeMasi, David B MacLeod, Philip N Ainslie
The determining mechanisms of a maximal hyperoxic apnea duration in elite apneists have remained unexplored. We tested the hypothesis that maximal hyperoxic apnea duration in elite apneists is related to forced vital capacity (FVC) but not the central chemoreflex (for CO2). Eleven elite apneists performed a maximal dry static-apnea with prior hyperoxic (100% oxygen) pre-breathing, and a central chemoreflex test via a hyperoxic re-breathing technique (hyperoxic-hypercapnic ventilatory response: HCVR); expressed as the increase in ventilation (pneumotachometry) per increase in arterial CO2 tension (PaCO2; radial artery)...
March 10, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28286249/immediate-effects-of-respiratory-muscle-stretching-on-chest-wall-kinematics-and-electromyography-in-copd-patients
#7
Rafaela Barros de Sá, Maíra Florentino Pessoa, Ana Gabriela Leal Cavalcanti, Shirley Lima Campos, César Amorim, Armèle Dornelas de Andrade
This study evaluated the immediate effects of respiratory muscle stretching on chest wall kinematics and electromyographic activity in COPD patients. 28 patients with COPD were randomized into two groups: 14 to the treatment group (TG) and 14 to the control group (CG). The TG underwent a stretching protocol of the rib cage muscles, while the CG remained at rest under similar conditions. After a single session, TG increased the tidal volume of the pulmonary rib cage (Vrcp) (p=0.020) and tidal volume of abdominal rib cage (Vrca) (p=0...
March 10, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28279732/intra-individual-variability-in-cerebrovascular-and-respiratory-chemosensitivity-can-we-characterize-a-chemoreflex-reactivity-profile
#8
Kennedy J Borle, Jamie R Pfoh, Lindsey M Boulet, Maria Abrosimova, Michael M Tymko, Rachel J Skow, Amy Varner, Trevor A Day
Intra-individual variability in the magnitude of human cerebrovascular and respiratory chemoreflex responses is largely unexplored. By comparing response magnitudes of cerebrovascular CO2 reactivity (CVR; middle and posterior cerebral arteries; MCA, PCA), central (CCR; CO2) and peripheral respiratory chemoreflexes (PCR; CO2 and O2), we tested the hypothesis that a within-individual reactivity magnitude profile could be characterized. The magnitudes of CVR and CCR were tested with hyperoxic rebreathing and PCR magnitudes were tested through transient respiratory tests (TT-CO2, hypercapnia; TT-N2, hypoxia)...
March 6, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28274780/analysis-of-heart-rate-and-oxygen-uptake-kinetics-studied-by-two-different-pseudo-random-binary-sequence-work-rate-amplitudes
#9
U Drescher, J Koschate, T Schiffer, S Schneider, U Hoffmann
PURPOSE: The aim of the study was to compare the kinetics responses of heart rate (HR), pulmonary (V'O2pulm) and predicted muscular (V'O2musc) oxygen uptake between two different pseudo-random binary sequence (PRBS) work rate (WR) amplitudes both below anaerobic threshold. METHODS: Eight healthy individuals performed two PRBS WR protocols implying changes between 30W to 80W and between 30W to 110W. HR and V'O2pulm were measured beat-to-beat and breath-by-breath, respectively...
March 5, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28259748/the-blood-transfer-conductance-for-co-and-no
#10
Colin Borland, J Michael B Hughes, Hervé Guénard
Nitric oxide was introduced over 30 years ago as a test gas for alveolar capillary diffusion. As for CO its transfer has been interpreted according to the Roughton Forster relationship: 1/DL=1/DM+1/θVc. There has been disagreement, since the first measurements of DLNO, over whether θNO is infinite and thus DLNO=DMNO. There is overwhelming in vitro evidence that θNO is finite yet several groups (Coffman et al., 2017; Tamhane et al., 2001) use an infinite value in vivo. They also assume that DMNO is greater than twice DMCO, making DMCO less than that predicted by the physical laws of diffusion...
March 1, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28249804/hypothesis-why-%C3%AE-no-could-be-finite-in-vitro-but-infinite-in-vivo
#11
Colin Borland, Suhani Patel, Qingyu Zhu, Alain Vuylsteke
There is controversy as to whether the lung Diffusing Capacity for Nitric Oxide (DLNO) is a direct measure of DM in the Roughton-Forster equation or whether θNO is finite and DM is greater than DLNO. Despite in vitro evidence that θNO is finite, some groups believe that it is infinite in vivo and that DMNO/DMCO (α) is greater than predicted by the combined Fick/Graham law of Gas Diffusion through a membrane. We here present a hypothesis applying the fundamental rules of combined diffusion and chemical reaction to a red cell to explain (i) why θNO could be finite in vitro but effectively infinite in vivo and (ii) why ∝ could appear greater than predicted...
February 26, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28238903/responsiveness-to-bronchodilator-procaterol-in-copd-as-assessed-by-forced-oscillation-technique
#12
Satoru Ito, Akemi Uchida, Yoshitaka Isobe, Yoshinori Hasegawa
The aim of this retrospective study was to assess responses to a bronchodilator by forced oscillation technique (FOT) and to relate the results of respiratory impedance (Zrs) to spirometric parameters in patients with chronic obstructive pulmonary disease (COPD). Zrs was measured as a function of frequency from 4 to 36Hz before and after inhalation of procaterol, a short-acting β2-agonist (n=60). Respiratory resistance (Rrs) and reactance (Xrs) were significantly frequency-dependent, and inspiratory and expiratory phases were different both before and after procaterol inhalation...
February 24, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28254562/cb1-receptor-mediated-respiratory-depression-by-endocannabinoids
#13
András Iring, László Hricisák, Zoltán Benyó
Endocannabinoids (ECs) are bioactive lipid mediators acting on two distinct cannabinoid receptors (CB1 and CB2), which are ubiquitously expressed in many tissues including the respiratory system. Despite numerous experimental data showing that cannabinomimetics influence respiration, the role of endogenously produced ECs in respiratory control has not been verified yet. Pulse oximetry was used in the present study to directly measure changes in respiratory parameters during elevation of EC levels. The cannabinoid reuptake inhibitor AM-404 (10mgkg(-1), i...
February 22, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28232221/respiratory-responses-to-progesterone-and-allopregnanolone-following-chronic-caffeine-treatment-in-newborn-female-rats
#14
Naga Praveena Uppari, Vincent Joseph, Aida Bairam
We recently showed that in 12-day-old male rats exposed to caffeine for 10 consecutive days, progesterone inhibits the respiratory response to hypoxia and increases apnea frequency (Uppari et al., 2016). This was partly due to a higher inhibitory response of GABAa receptor to allopregnanolone, the neuroactive metabolite of progesterone. In the present study, we addressed whether similar effects occur in females. We used newborn female rats daily gavaged with water (control) or caffeine (15mg/kg) between the postnatal (P) days 3-12...
February 20, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28232071/expiratory-flow-limitation-and-operating-lung-volumes-during-exercise-in-older-and-younger-adults
#15
Joshua R Smith, Stephanie P Kurti, Kayla Meskimen, Craig A Harms
We determined the effect of aging on expiratory flow limitation (EFL) and operating lung volumes when matched for lung size. We hypothesized that older adults will exhibit greater EFL and increases in EELV during exercise compared to younger controls. Ten older (5M/5W; >60years old) and nineteen height-matched young adults (10M/9W) were recruited. Young adults were matched for%predicted forced vital capacity (FVC) (Y-matched%Pred FVC; n=10) and absolute FVC (Y-matched FVC; n=10). Tidal flow-volume loops were recorded during the incremental exercise test with maximal flow-volume loops measured pre- and post-exercise...
February 20, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28219747/is-pulmonary-diffusion-capacity-for-nitric-oxide-dl-no-likely-to-become-a-routine-pulmonary-function-test
#16
Irene Steenbruggen, Frans de Jongh
DL,CO measurements are often used to evaluate and monitor lung diseases as well as cardiovascular diseases. Whether the combination of DL,CO and DL,NO will improve the management of cardiovascular diseases needs to be investigated. It is hoped that the standardization of the DL,NO measurement will facilitate research. Scientific evidence that DL,NO can provide more accurate information than DL,CO alone, can take away the barriers that prevents DL,NO to become a routine test in pulmonology.
February 17, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28215595/gas-exchange-kinetics-following-concentric-eccentric-isokinetic-arm-and-leg-exercise
#17
U Drescher, S Mookerjee, A Steegmanns, A Knicker, U Hoffmann
PURPOSE: To evaluate the effects of exercise velocity (60, 150, 240deg∙s(-1)) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO2) following high-intensity concentric-eccentric isokinetic exercise. METHODS: Fourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t1/2) for oxygen uptake (V˙O2pulm), carbon dioxide output (V˙CO2pulm), and ventilation (V˙E)...
February 17, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28215596/sex-specific-respiratory-effects-of-acute-and-chronic-caffeine-administration-in-newborn-rats
#18
REVIEW
Hayet Kouchi, NagaPraveena Uppari, Vincent Joseph, Aida Bairam
Caffeine is widely used for the treatment of apnea of prematurity (AoP) but whether this effect varies with sex is unknown. To shed some light on this question, we present a summary of data obtained on the effects of caffeine on the respiratory chemoreflexes and apnea frequency in 1- and 12-days old male and female rats. Caffeine was either administered as a single acute injection (10mg/kg, i.p.) or for 10 consecutive days (7.5mg/kg/day between 3 and 12days of life by gavage, simulating its clinical use). Acute caffeine had little effects on breathing in 1-day old male and female rats...
February 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28214605/the-effect-of-sitting-and-calf-activity-on-leg-fluid-and-snoring
#19
Bhajan Singh, Azadeh Yadollahi, Owen Lyons, Hisham Alshaer, T Douglas Bradley
Prolonged sitting may promote leg fluid retention that redistributes to the neck during sleep and contributes to snoring. This could be attenuated by calf activity while sitting. In 16 healthy non-obese subjects we measured leg fluid volume (LFV) below the knees using bioelectrical impedance while sitting for 4h, snoring using a portable BresoDx™ device, and Mallampati grade. Using a double cross-over study design, subjects were randomized to one of two arms and crossed-over one week later: control arm - no calf exercise while sitting; intervention arm - calf contraction against a pedal resistance while sitting...
February 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28213202/determinants-of-cough-effectiveness-in-patients-with-respiratory-muscle-weakness
#20
Franco Laghi, Veeranna Maddipati, Timothy Schnell, W Edwin Langbein, Martin J Tobin
Experiments were undertaken to mechanistically define expiratory-muscle contribution to effectiveness of cough while controlling glottic movement. We hypothesized that electrical abdominal-muscle stimulation in patients with respiratory-muscle weakness produces effective coughs only when glottic closure accompanies coughs. In ten spinal-cord-injury patients, esophago-gastric pressure and airflow were recorded during solicited-coughs, coughs augmented by abdominal-muscle stimulation, and passive open-glottis exhalations...
February 16, 2017: Respiratory Physiology & Neurobiology
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