Silicon central pattern generators for cardiac diseases

PubMed Central

Nogaret, Alain; O'Callaghan, Erin L; Lataro, Renata M; Salgado, Helio C; Meliza, C Daniel; Duncan, Edward; Abarbanel, Henry D I; Paton, Julian F R

2015-01-01

Cardiac rhythm management devices provide therapies for both arrhythmias and resynchronisation but not heart failure, which affects millions of patients worldwide. This paper reviews recent advances in biophysics and mathematical engineering that provide a novel technological platform for addressing heart disease and enabling beat-to-beat adaptation of cardiac pacing in response to physiological feedback. The technology consists of silicon hardware central pattern generators (hCPGs) that may be trained to emulate accurately the dynamical response of biological central pattern generators (bCPGs). We discuss the limitations of present CPGs and appraise the advantages of analog over digital circuits for application in bioelectronic medicine. To test the system, we have focused on the cardio-respiratory oscillators in the medulla oblongata that modulate heart rate in phase with respiration to induce respiratory sinus arrhythmia (RSA). We describe here a novel, scalable hCPG comprising physiologically realistic (Hodgkin–Huxley type) neurones and synapses. Our hCPG comprises two neurones that antagonise each other to provide rhythmic motor drive to the vagus nerve to slow the heart. We show how recent advances in modelling allow the motor output to adapt to physiological feedback such as respiration. In rats, we report on the restoration of RSA using an hCPG that receives diaphragmatic electromyography input and use it to stimulate the vagus nerve at specific time points of the respiratory cycle to slow the heart rate. We have validated the adaptation of stimulation to alterations in respiratory rate. We demonstrate that the hCPG is tuneable in terms of the depth and timing of the RSA relative to respiratory phase. These pioneering studies will now permit an analysis of the physiological role of RSA as well as its any potential therapeutic use in cardiac disease. PMID:25433077

Respiratory muscles stretching acutely increases expansion in hemiparetic chest wall.

PubMed

Rattes, Catarina; Campos, Shirley Lima; Morais, Caio; Gonçalves, Thiago; Sayão, Larissa Bouwman; Galindo-Filho, Valdecir Castor; Parreira, Verônica; Aliverti, Andrea; Dornelas de Andrade, Armèle

2018-08-01

Individuals post-stroke may present restrictive ventilatory pattern generated from changes in the functionality of respiratory system due to muscle spasticity and contractures. Objective was to assess the acute effects after respiratory muscle stretching on the ventilatory pattern and volume distribution of the chest wall in stroke subjects. Ten volunteers with right hemiparesis after stroke and a mean age of 60 ± 5.7 years were randomised into the following interventions: respiratory muscle stretching and at rest (control). The ventilatory pattern and chest wall volume distribution were evaluated through optoelectronic plethysmography before and immediately after each intervention. Respiratory muscle stretching promoted a significant acute increase of 120 mL in tidal volume, with an increase in minute ventilation, mean inspiratory flow and mean expiratory flow compared with the control group. Pulmonary ribcage increased 50 mL after stretching, with 30 mL of contribution to the right pulmonary rib cage (hemiparetic side) in comparison to the control group. Respiratory muscle stretching in patients with right hemiparesis post-stroke demonstrated that acute effects improve the expansion of the respiratory system during tidal breathing. NCT02416349 (URL: https://clinicaltrials.gov/ct2/show/ NCT02416349). Copyright © 2018 Elsevier B.V. All rights reserved.

Networks within networks: The neuronal control of breathing

PubMed Central

Garcia, Alfredo J.; Zanella, Sebastien; Koch, Henner; Doi, Atsushi; Ramirez, Jan-Marino

2013-01-01

Breathing emerges through complex network interactions involving neurons distributed throughout the nervous system. The respiratory rhythm generating network is composed of micro networks functioning within larger networks to generate distinct rhythms and patterns that characterize breathing. The pre-Bötzinger complex, a rhythm generating network located within the ventrolateral medulla assumes a core function without which respiratory rhythm generation and breathing cease altogether. It contains subnetworks with distinct synaptic and intrinsic membrane properties that give rise to different types of respiratory rhythmic activities including eupneic, sigh, and gasping activities. While critical aspects of these rhythmic activities are preserved when isolated in in vitro preparations, the pre-Bötzinger complex functions in the behaving animal as part of a larger network that receives important inputs from areas such as the pons and parafacial nucleus. The respiratory network is also an integrator of modulatory and sensory inputs that imbue the network with the important ability to adapt to changes in the behavioral, metabolic, and developmental conditions of the organism. This review summarizes our current understanding of these interactions and relates the emerging concepts to insights gained in other rhythm generating networks. PMID:21333801

Laser ablation of Dbx1 neurons in the pre-Bötzinger complex stops inspiratory rhythm and impairs output in neonatal mice

PubMed Central

Wang, Xueying; Hayes, John A; Revill, Ann L; Song, Hanbing; Kottick, Andrew; Vann, Nikolas C; LaMar, M Drew; Picardo, Maria Cristina D; Akins, Victoria T; Funk, Gregory D; Del Negro, Christopher A

2014-01-01

To understand the neural origins of rhythmic behavior one must characterize the central pattern generator circuit and quantify the population size needed to sustain functionality. Breathing-related interneurons of the brainstem pre-Bötzinger complex (preBötC) that putatively comprise the core respiratory rhythm generator in mammals are derived from Dbx1-expressing precursors. Here, we show that selective photonic destruction of Dbx1 preBötC neurons in neonatal mouse slices impairs respiratory rhythm but surprisingly also the magnitude of motor output; respiratory hypoglossal nerve discharge decreased and its frequency steadily diminished until rhythm stopped irreversibly after 85±20 (mean ± SEM) cellular ablations, which corresponds to ∼15% of the estimated population. These results demonstrate that a single canonical interneuron class generates respiratory rhythm and contributes in a premotor capacity, whereas these functions are normally attributed to discrete populations. We also establish quantitative cellular parameters that govern network viability, which may have ramifications for respiratory pathology in disease states. DOI: http://dx.doi.org/10.7554/eLife.03427.001 PMID:25027440

Peripheral mechanisms for vocal production in birds - differences and similarities to human speech and singing.

PubMed

Riede, Tobias; Goller, Franz

2010-10-01

Song production in songbirds is a model system for studying learned vocal behavior. As in humans, bird phonation involves three main motor systems (respiration, vocal organ and vocal tract). The avian respiratory mechanism uses pressure regulation in air sacs to ventilate a rigid lung. In songbirds sound is generated with two independently controlled sound sources, which reside in a uniquely avian vocal organ, the syrinx. However, the physical sound generation mechanism in the syrinx shows strong analogies to that in the human larynx, such that both can be characterized as myoelastic-aerodynamic sound sources. Similarities include active adduction and abduction, oscillating tissue masses which modulate flow rate through the organ and a layered structure of the oscillating tissue masses giving rise to complex viscoelastic properties. Differences in the functional morphology of the sound producing system between birds and humans require specific motor control patterns. The songbird vocal apparatus is adapted for high speed, suggesting that temporal patterns and fast modulation of sound features are important in acoustic communication. Rapid respiratory patterns determine the coarse temporal structure of song and maintain gas exchange even during very long songs. The respiratory system also contributes to the fine control of airflow. Muscular control of the vocal organ regulates airflow and acoustic features. The upper vocal tract of birds filters the sounds generated in the syrinx, and filter properties are actively adjusted. Nonlinear source-filter interactions may also play a role. The unique morphology and biomechanical system for sound production in birds presents an interesting model for exploring parallels in control mechanisms that give rise to highly convergent physical patterns of sound generation. More comparative work should provide a rich source for our understanding of the evolution of complex sound producing systems. Copyright © 2009 Elsevier Inc. All rights reserved.

Spatial Correlation Analysis between Particulate Matter 10 (PM10) Hazard and Respiratory Diseases in Chiang Mai Province, Thailand

NASA Astrophysics Data System (ADS)

Trang, N. Ha; Tripathi, N. K.

2014-11-01

Every year, during dry season, Chiang Mai and other northern provinces of Thailand face the problem of haze which is mainly generated by the burning of agricultural waste and forest fire, contained high percentage of particulate matter. Particulate matter 10 (PM10), being very small in size, can be inhaled easily to the deepest parts of the human lung and throat respiratory functions. Due to this, it increases the risk of respiratory diseases mainly in the case of continuous exposure to this seasonal smog. MODIS aerosol images (MOD04) have been used for four weeks in March 2007 for generating the hazard map by linking to in-situ values of PM10. Simple linear regression model between PM10 and AOD got fair correlation with R2 = 0.7 and was applied to transform PM10 pattern. The hazard maps showed the dominance of PM10 in northern part of Chiang Mai, especially in second week of March when PM10 level was three to four times higher than standard. The respiratory disease records and public health station of each village were collected from Provincial Public Health Department in Chiang Mai province. There are about 300 public health stations out of 2070 villages; hence thiessen polygon was created to determine the representative area of each public health station. Within each thiessen polygon, respiratory disease incident rate (RDIR) was calculated based on the number of patients and population. Global Moran's I was computed for RDIR to explore spatial pattern of diseases through four weeks of March. Moran's I index depicted a cluster pattern of respiratory diseases in 2nd week than other weeks. That made sense for a relationship between PM10 and respiratory diseases infections. In order to examine how PM10 affect the human respiratory system, geographically weighted regression model was used to observe local correlation coefficient between RDIR and PM10 across study area. The result captured a high correlation between respiratory diseases and high level of PM10 in northeast districts of Chiang Mai in second week of March.

Reciprocal functional interactions between the brainstem and the lower spinal cord

PubMed Central

Yazawa, Itaru

2014-01-01

The interplay of the neuronal discharge patterns regarding respiration and locomotion was investigated using electrophysiological techniques in a decerebrate and arterially perfused in situ mouse preparation. The phrenic, tibial, and/or peroneal nerve discharge became clearly organized into discharge episodes of increasing frequency and duration, punctuated by periods of quiescence as the perfusion flow rate increased at room temperature. The modulated sympathetic tone induced by the hyperoxic/normocapnic state was found to activate the locomotor pattern generator (LPG) via descending pathways and generate a left and right alternating discharge during discharge episodes in the motor nerves. The rhythm coupling of respiration and locomotion occurred at a 1:1 frequency ratio. Although the phrenic discharge synchronized with the tibial discharge at all flow rates tested, the time lag between peaks of the two discharges during locomotion was ≈400 ms rather than ≈200 ms, suggesting spinal feedback via ascending pathways. The incidence of the phrenic and tibial discharge episodes decreased by ≈50% after spinalization at the twelfth thoracic cord and the respiratory rhythm was more regular. These results indicate that: (i) locomotion can be generated in a hyperoxic/normocapnic state induced by specific respiratory conditions, (ii) the central mechanism regarding entrainment of respiratory and locomotor rhythms relies on spinal feedback via ascending pathways, initiated by the activated LPG generating locomotion, and (iii) the increase in respiratory rate seen during locomotion is caused not only by afferent mechanical and nociceptive inputs but also by impulses from the activated spinal cord producing a locomotor-like discharge via ascending pathways. PMID:24910591

Usefulness of a new online patient-specific quality assurance system for respiratory-gated radiotherapy.

PubMed

Kurosawa, Tomoyuki; Tachibana, Hidenobu; Moriya, Shunsuke; Miyakawa, Shin; Nishio, Teiji; Sato, Masanori

2017-11-01

The accuracy of gated irradiation may decrease when treatment is performed with short "beam-on" times. Also, the dose is subject to variation between treatment sessions if the respiratory rate is irregular. We therefore evaluated the impact of the differences between gated and non-gated treatment on doses using a new online quality assurance (QA) system for respiratory-gated radiotherapy. We generated dose estimation models to associate dose and pulse information using a 0.6 cc Farmer chamber and our QA system. During gated irradiation with each of seven regular and irregular respiratory patterns, with the Farmer chamber readings as references, we evaluated our QA system's accuracy. We then used the QA system to assess the impact of respiratory patterns on dose distribution for three lung and three liver radiotherapy plans. Gated and non-gated plans were generated and compared. There was agreement within 1.7% between the ionization chamber and our system for several regular and irregular motion patterns. For dose distributions with measured errors, there were larger differences between gated and non-gated treatment for high-dose regions within the planned treatment volume (PTV). Compared with a non-gated plan, PTV D 95% for a gated plan decreased by -1.5% to -2.6%. Doses to organs at risk were similar with both plans. Our simple system estimated the radiation dose to the patient using only pulse information from the linac, even during irregular respiration. The quality of gated irradiation for each patient can be verified fraction by fraction. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Brainstem mechanisms underlying the cough reflex and its regulation.

PubMed

Mutolo, Donatella

2017-09-01

Cough is a very important airway protective reflex. Cough-related inputs are conveyed to the caudal nucleus tractus solitarii (cNTS) that projects to the brainstem respiratory network. The latter is reconfigured to generate the cough motor pattern. A high degree of modulation is exerted on second-order neurons and the brainstem respiratory network by sensory inputs and higher brain areas. Two medullary structures proved to have key functions in cough production and to be strategic sites of action for centrally active drugs: the cNTS and the caudal ventral respiratory group (cVRG). Drugs microinjected into these medullary structures caused downregulation or upregulation of the cough reflex. The results suggest that inhibition and disinhibition are prominent regulatory mechanisms of this reflex and that both the cNTS and the cVRG are essential in the generation of the entire cough motor pattern. Studies on the basic neural mechanisms subserving the cough reflex may provide hints for novel therapeutic approaches. Different proposals for further investigations are advanced. Copyright © 2017 Elsevier B.V. All rights reserved.

[Central Pattern Generators: Mechanisms of the Activity and Their Role in the Control of "Automatic" Movements].

PubMed

Arshavsky, I; Deliagina, T G; Orlovsky, G N

2015-01-01

Central pattern generators (CPGs) are a set of interconnected neurons capable of generating a basic pattern of motor output underlying "automatic" movements (breathing, locomotion, chewing, swallowing, and so on) in the absence of afferent signals from the executive motor apparatus. They can be divided into the constitutive CPGs active throughout the entire lifetime (respiratory CPGs) and conditional CPGs controlling episodic movements (locomotion, chewing, swallowing, and others). Since a motor output of CPGs is determined by their internal organization, the activities of the conditional CPGs are initiated by simple commands coming from higher centers. We describe the structural and functional organization of the locomotor CPGs in the marine mollusk Clione limacina, lamprey, frog embryo, and laboratory mammals (cat, mouse, and rat), CPGs controlling the respiratory and swallowing movements in mammals, and CPGs controlling discharges of the electric organ in the gymnotiform fish. It is shown that in all these cases, the generation of rhythmic motor output is based both on the endogenous (pacemaker) activity of specific groups of interneurons and on interneural interactions. These two interrelated mechanisms complement each other, ensuring the high reliability of CPG functionality. We discuss how the experience obtained in studying CPGs can be used to understand mechanisms of more complex functions of the brain, including its cognitive functions.

Respiration in vitro: I. Spontaneous activity.

PubMed

Hamada, O; Garcia-Rill, E; Skinner, R D

1992-01-01

The present report describes respiratory-like activity recorded from intercostal muscles in the neonatal rat in vitro brain stem-spinal cord, rib-attached preparation. In this preparation from 1- to 4-day-old rats, spontaneous rhythmic and synchronized upward movements of the rib cage coincided with the recorded muscle activity. Spontaneous respiratory-like activity showed a frequency in the range of 0.05-0.2 Hz, with single-, double-, and mixed-burst patterns. Spontaneous activity declined over time, but increased in frequency as temperature increased. Multilevel recordings showed a cephalocaudal order of bursting of intercostal muscles. Brain stem transections at the prepontine level did not affect spontaneous frequency, whereas premedullary transections resulted in an increase in spontaneous respiratory frequency. High spinal transections eliminated spontaneous respiratory-like activity. These results suggest that there is a well-organized pontomedullary pattern generator for respiratory-like activity in this preparation, which can be modulated by temperature. The characteristics of these electromyographic (EMG) recordings allow comparison with previous in vitro studies of respiratory-like activity using nerve activity and in vivo studies using EMG activity. These results provide basic information on the spontaneous activity of this preparation as a prelude to the study of the effects of electrical stimulation of the spinal cord to induce respiratory-like activity, as described in the companion article.

Age-specific excess mortality patterns and transmissibility during the 1889-1890 influenza pandemic in Madrid, Spain.

PubMed

Ramiro, Diego; Garcia, Sara; Casado, Yolanda; Cilek, Laura; Chowell, Gerardo

2018-05-01

Although the 1889-1890 influenza pandemic was one of the most important epidemic events of the 19th century, little is known about the mortality impact of this pandemic based on detailed respiratory mortality data sets. We estimated excess mortality rates for the 1889-1890 pandemic in Madrid from high-resolution respiratory and all-cause individual-level mortality data retrieved from the Gazeta de Madrid, the Official Bulletin of the Spanish government. We also generated estimates of the reproduction number from the early growth phase of the pandemic. The main pandemic wave in Madrid was evident from respiratory and all-cause mortality rates during the winter of 1889-1890. Our estimates of excess mortality for this pandemic were 58.3 per 10,000 for all-cause mortality and 44.5 per 10,000 for respiratory mortality. Age-specific excess mortality rates displayed a J-shape pattern, with school children aged 5-14 years experiencing the lowest respiratory excess death rates (8.8 excess respiratory deaths per 10,000), whereas older populations aged greater than or equal to 70 years had the highest rates (367.9 per 10,000). Although seniors experienced the highest absolute excess death rates, the standardized mortality ratio was highest among young adults aged 15-24 years. The early growth phase of the pandemic displayed dynamics consistent with an exponentially growing transmission process. Using the generalized-growth method, we estimated the reproduction number in the range of 1.2-1.3 assuming a 3-day mean generation interval and of 1.3-1.5 assuming a 4-day mean generation interval. Our study adds to our understanding of the mortality impact and transmissibility of the 1889-1890 influenza pandemic using detailed individual-level mortality data sets. More quantitative studies are needed to quantify the variability of the mortality impact of this understudied pandemic at regional and global scales. Copyright © 2017 Elsevier Inc. All rights reserved.

Transient Receptor Potential Channels TRPM4 and TRPC3 Critically Contribute to Respiratory Motor Pattern Formation but not Rhythmogenesis in Rodent Brainstem Circuits

PubMed Central

Tariq, Mohammad F.; Phillips, Ryan S.; Mosher, Bryan; Thompson, Ryan; Zhang, Ruli

2018-01-01

Abstract Transient receptor potential channel, TRPM4, the putative molecular substrate for Ca2+-activated nonselective cation current (ICAN), is hypothesized to generate bursting activity of pre-Bötzinger complex (pre-BötC) inspiratory neurons and critically contribute to respiratory rhythmogenesis. Another TRP channel, TRPC3, which mediates Na+/Ca2+ fluxes, may be involved in regulating Ca2+-related signaling, including affecting TRPM4/ICAN in respiratory pre-BötC neurons. However, TRPM4 and TRPC3 expression in pre-BötC inspiratory neurons and functional roles of these channels remain to be determined. By single-cell multiplex RT-PCR, we show mRNA expression for these channels in pre-BötC inspiratory neurons in rhythmically active medullary in vitro slices from neonatal rats and mice. Functional contributions were analyzed with pharmacological inhibitors of TRPM4 or TRPC3 in vitro as well as in mature rodent arterially perfused in situ brainstem–spinal cord preparations. Perturbations of respiratory circuit activity were also compared with those by a blocker of ICAN. Pharmacologically attenuating endogenous activation of TRPM4, TRPC3, or ICAN in vitro similarly reduced the amplitude of inspiratory motoneuronal activity without significant perturbations of inspiratory frequency or variability of the rhythm. Amplitude perturbations were correlated with reduced inspiratory glutamatergic pre-BötC neuronal activity, monitored by multicellular dynamic calcium imaging in vitro. In more intact circuits in situ, the reduction of pre-BötC and motoneuronal inspiratory activity amplitude was accompanied by reduced post-inspiratory motoneuronal activity, without disruption of rhythm generation. We conclude that endogenously activated TRPM4, which likely mediates ICAN, and TRPC3 channels in pre-BötC inspiratory neurons play fundamental roles in respiratory pattern formation but are not critically involved in respiratory rhythm generation. PMID:29435486

A Sodium Leak Current Regulates Pacemaker Activity of Adult Central Pattern Generator Neurons in Lymnaea Stagnalis

PubMed Central

Lu, Tom Z.; Feng, Zhong-Ping

2011-01-01

The resting membrane potential of the pacemaker neurons is one of the essential mechanisms underlying rhythm generation. In this study, we described the biophysical properties of an uncharacterized channel (U-type channel) and investigated the role of the channel in the rhythmic activity of a respiratory pacemaker neuron and the respiratory behaviour in adult freshwater snail Lymnaea stagnalis. Our results show that the channel conducts an inward leak current carried by Na+ (ILeak-Na). The ILeak-Na contributed to the resting membrane potential and was required for maintaining rhythmic action potential bursting activity of the identified pacemaker RPeD1 neurons. Partial knockdown of the U-type channel suppressed the aerial respiratory behaviour of the adult snail in vivo. These findings identified the Na+ leak conductance via the U-type channel, likely a NALCN-like channel, as one of the fundamental mechanisms regulating rhythm activity of pacemaker neurons and respiratory behaviour in adult animals. PMID:21526173

Activation of respiratory muscles does not occur during cold-submergence in bullfrogs, Lithobates catesbeianus.

PubMed

Santin, Joseph M; Hartzler, Lynn K

2017-04-01

Semiaquatic frogs may not breathe air for several months because they overwinter in ice-covered ponds. In contrast to many vertebrates that experience decreased motor performance after inactivity, bullfrogs, Lithobates catesbeianus , retain functional respiratory motor processes following cold-submergence. Unlike mammalian hibernators with unloaded limb muscles and inactive locomotor systems, respiratory mechanics of frogs counterintuitively allow for ventilatory maneuvers when submerged. Thus, we hypothesized that bullfrogs generate respiratory motor patterns during cold-submergence to avoid disuse and preserve motor performance. Accordingly, we measured activity of respiratory muscles (buccal floor compressor and glottal dilator) via electromyography in freely behaving bullfrogs at 20 and 2°C. Although we confirm that ventilation cycles occur underwater at 20°C, bullfrogs did not activate either respiratory muscle when submerged acutely or chronically at 2°C. We conclude that cold-submerged bullfrogs endure respiratory motor inactivity, implying that other mechanisms, excluding underwater muscle activation, maintain a functional respiratory motor system throughout overwintering. © 2017. Published by The Company of Biologists Ltd.

Breathing simulator of workers for respirator performance test.

PubMed

Yuasa, Hisashi; Kumita, Mikio; Honda, Takeshi; Kimura, Kazushi; Nozaki, Kosuke; Emi, Hitoshi; Otani, Yoshio

2015-01-01

Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker's respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns.

SU-E-T-651: Quantification of Dosimetric Accuracy of Respiratory Gated Stereotactic Body Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thiyagarajan, Rajesh; Vikraman, S; Maragathaveni, S

2015-06-15

Purpose: To quantify the dosimetric accuracy of respiratory gated stereotactic body radiation therapy delivery using dynamic thorax phantom. Methods: Three patients with mobile target (2 lung, 1liver) were chosen. Retrospective 4DCT image sets were acquired for using Varian RPM system. An in-house MATLAB program was designed for MIP, MinIP and AvgIP generation. ITV was contoured on MIP image set for lung patients and on MinIP for liver patient. Dynamic IMRT plans were generated on selected phase bin image set in Eclipse (v10.0) planning system. CIRS dynamic thorax phantom was used to perform the dosimetric quality assurance. Patient breathing pattern filemore » from RPM system was converted to phantom compatible file by an in-house MATLAB program. This respiratory pattern fed to the CIRS dynamic thorax phantom. 4DCT image set was acquired for this phantom using patient breathing pattern. Verification plans were generated using patient gating window and delivered on the phantom. Measurements were carried out using with ion chamber and EBT2 film. Exposed films were analyzed and evaluated in FilmQA software. Results: The stability of gated output in comparison with un-gated output was within 0.5%. The Ion chamber measured and TPS calculated dose compared for all the patients. The difference observed was 0.45%, −0.52% and −0.54 for Patient 1, Patient2 and Patient 3 respectively.Gamma value evaluated from EBT film shows pass rates from 92.41% to 99.93% for 3% dose difference and 3mm distance to agreement criteria. Conclusion: Dosimetric accuracy of respiratory gated SBRT delivery for lung and liver was dosimetrically acceptable. The Ion chamber measured dose was within 0.203±0.5659% of the expected dose. Gamma pass rates were within 96.63±3.84% of the expected dose.« less

Sleep-disordered breathing after targeted ablation of preBötzinger complex neurons.

PubMed

McKay, Leanne C; Janczewski, Wiktor A; Feldman, Jack L

2005-09-01

Ablation of preBötzinger complex (preBötC) neurons, critical for respiratory rhythm generation, resulted in a progressive, increasingly severe disruption of respiratory pattern, initially during sleep and then also during wakefulness in adult rats. Sleep-disordered breathing is highly prevalent in elderly humans and in some patients with neurodegenerative disease. We propose that sleep-disordered breathing results from loss of preBötC neurons and could underlie death during sleep in these populations.

Sleep-disordered breathing after targeted ablation of preBötzinger complex neurons

PubMed Central

McKay, Leanne C; Janczewski, Wiktor A; Feldman, Jack L

2010-01-01

Ablation of preBötzinger complex (preBötC) neurons, critical for respiratory rhythm generation, resulted in a progressive, increasingly severe disruption of respiratory pattern, initially during sleep and then also during wakefulness in adult rats. Sleep-disordered breathing is highly prevalent in elderly humans and in some patients with neurodegenerative disease. We propose that sleep-disordered breathing results from loss of preBötC neurons and could underlie death during sleep in these populations. PMID:16116455

Discharge properties of upper airway motor units during wakefulness and sleep.

PubMed

Trinder, John; Jordan, Amy S; Nicholas, Christian L

2014-01-01

Upper airway muscle motoneurons, as assessed at the level of the motor unit, have a range of different discharge patterns, varying as to whether their activity is modulated in phase with the respiratory cycle, are predominantly inspiratory or expiratory, or are phasic as opposed to tonic. Two fundamental questions raised by this observation are: how are synaptic inputs from premotor neurons distributed over motoneurons to achieve these different discharge patterns; and how do different discharge patterns contribute to muscle function? We and others have studied the behavior of genioglossus (GG) and tensor palatini (TP) single motor units at transitions from wakefulness to sleep (sleep onset), from sleep to wakefulness (arousal from sleep), and during hypercapnia. Results indicate that decreases or increases in GG and TP muscle activity occur as a consequence of derecruitment or recruitment, respectively, of phasic and tonic inspiratory-modulated motoneurons, with only minor changes in rate coding. Further, sleep-wake state and chemical inputs to this "inspiratory system" appear to be mediated through the respiratory pattern generator. In contrast, phasic and tonic expiratory units and units with a purely tonic pattern, the "tonic system," are largely unaffected by sleep-wake state, and are only weakly influenced by chemical stimuli and the respiratory cycle. We speculate that the "inspiratory system" produces gross changes in upper airway muscle activity in response to changes in respiratory drive, while the "tonic system" fine tunes airway configuration with activity in this system being determined by local mechanical conditions. © 2014 Elsevier B.V. All rights reserved.

Timescales and Mechanisms of Sigh-Like Bursting and Spiking in Models of Rhythmic Respiratory Neurons.

PubMed

Wang, Yangyang; Rubin, Jonathan E

2017-12-01

Neural networks generate a variety of rhythmic activity patterns, often involving different timescales. One example arises in the respiratory network in the pre-Bötzinger complex of the mammalian brainstem, which can generate the eupneic rhythm associated with normal respiration as well as recurrent low-frequency, large-amplitude bursts associated with sighing. Two competing hypotheses have been proposed to explain sigh generation: the recruitment of a neuronal population distinct from the eupneic rhythm-generating subpopulation or the reconfiguration of activity within a single population. Here, we consider two recent computational models, one of which represents each of the hypotheses. We use methods of dynamical systems theory, such as fast-slow decomposition, averaging, and bifurcation analysis, to understand the multiple-timescale mechanisms underlying sigh generation in each model. In the course of our analysis, we discover that a third timescale is required to generate sighs in both models. Furthermore, we identify the similarities of the underlying mechanisms in the two models and the aspects in which they differ.

Anatomical architecture and responses to acidosis of a novel respiratory neuron group in the high cervical spinal cord (HCRG) of the neonatal rat.

PubMed

Okada, Y; Yokota, S; Shinozaki, Y; Aoyama, R; Yasui, Y; Ishiguro, M; Oku, Y

2009-01-01

It has been postulated that there exists a neuronal mechanism that generates respiratory rhythm and modulates respiratory output pattern in the high cervical spinal cord. Recently, we have found a novel respiratory neuron group in the ventral portion of the high cervical spinal cord, and named it the high cervical spinal cord respiratory group (HCRG). In the present study, we analyzed the detailed anatomical architecture of the HCRG region by double immunostaining of the region using a neuron-specific marker (NeuN) and a marker for motoneurons (ChAT) in the neonatal rat. We found a large number of small NeuN-positive cells without ChAT-immunoreactivity, which were considered interneurons. We also found two and three clusters of motoneurons in the ventral portion of the ventral horn at C1 and C2 levels, respectively. Next, we examined responses of HCRG neurons to respiratory and metabolic acidosis in vitro by voltage-imaging together with cross correlation techniques, i.e., by correlation coefficient imaging, in order to understand the functional role of HCRG neurons. Both respiratory and metabolic acidosis caused the same pattern of changes in their spatiotemporal activation profiles, and the respiratory-related area was enlarged in the HCRG region. After acidosis was introduced, preinspiratory phase-dominant activity was recruited in a number of pixels, and more remarkably inspiratory phase-dominant activity was recruited in a large number of pixels. We suggest that the HCRG composes a local respiratory neuronal network consisting of interneurons and motoneurons and plays an important role in respiratory augmentation in response to acidosis.

The action of the insecticide imidacloprid on the respiratory rhythm of an insect: the beetle Tenebrio molitor.

PubMed

Zafeiridou, Georgia; Theophilidis, George

2004-07-29

Imidacloprid is an insecticide which has the nicotinic acetylcholine receptors (nAChRs) as its primary site of action; acetylcholine is the major excitatory neurotransmitter in the insect central nervous system (CNS). In this study, the action of imidacloprid was tested using the synapses of the respiratory central pattern generator of the beetle Tenebrio molitor. The no observed effect concentration (NOEC) for imidacloprid was estimated to be between 0.001 and 0.010 microM. A concentration of 0.10 microM caused hyperexcitation in firing of the respiratory motoneurons, while the concentration of 1.00 microM caused an abrupt increase in their frequency and then a complete inhibition of the activity of the respiratory motoneurons. The possible implication of the action of such low concentrations of imidacloprid in the contraction of the respiratory muscles is also demonstrated and discussed.

Developmental nicotine exposure adversely effects respiratory patterning in the barbiturate anesthetized neonatal rat.

PubMed

Barreda, Santiago; Kidder, Ian J; Mudery, Jordan A; Bailey, E Fiona

2015-03-01

Neonates at risk for sudden infant death syndrome (SIDS) are hospitalized for cardiorespiratory monitoring however, monitoring is costly and generates large quantities of averaged data that serve as poor predictors of infant risk. In this study we used a traditional autocorrelation function (ACF) testing its suitability as a tool to detect subtle alterations in respiratory patterning in vivo. We applied the ACF to chest wall motion tracings obtained from rat pups in the period corresponding to the mid-to-end of the third trimester of human pregnancy. Pups were drawn from two groups: nicotine-exposed and saline-exposed at each age (i.e., P7, P8, P9, and P10). Respiratory-related motions of the chest wall were recorded in room air and in response to an arousal stimulus (FIO2 14%). The autocorrelation function was used to determine measures of breathing rate and respiratory patterning. Unlike alternative tools such as Poincare plots that depict an averaged difference in a measure breath to breath, the ACF when applied to a digitized chest wall trace yields an instantaneous sample of data points that can be used to compare (data) points at the same time in the next breath or in any subsequent number of breaths. The moment-to-moment evaluation of chest wall motion detected subtle differences in respiratory pattern in rat pups exposed to nicotine in utero and aged matched saline-exposed peers. The ACF can be applied online as well as to existing data sets and requires comparatively short sampling windows (∼2 min). As shown here, the ACF could be used to identify factors that precipitate or minimize instability and thus, offers a quantitative measure of risk in vulnerable populations. Copyright © 2015 Elsevier B.V. All rights reserved.

Breathing simulator of workers for respirator performance test

PubMed Central

YUASA, Hisashi; KUMITA, Mikio; HONDA, Takeshi; KIMURA, Kazushi; NOZAKI, Kosuke; EMI, Hitoshi; OTANI, Yoshio

2014-01-01

Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker’s respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns. PMID:25382381

APEX_SCOPE: A graphical user interface for visualization of multi-modal data in inter-disciplinary studies.

PubMed

Kanbar, Lara J; Shalish, Wissam; Precup, Doina; Brown, Karen; Sant'Anna, Guilherme M; Kearney, Robert E

2017-07-01

In multi-disciplinary studies, different forms of data are often collected for analysis. For example, APEX, a study on the automated prediction of extubation readiness in extremely preterm infants, collects clinical parameters and cardiorespiratory signals. A variety of cardiorespiratory metrics are computed from these signals and used to assign a cardiorespiratory pattern at each time. In such a situation, exploratory analysis requires a visualization tool capable of displaying these different types of acquired and computed signals in an integrated environment. Thus, we developed APEX_SCOPE, a graphical tool for the visualization of multi-modal data comprising cardiorespiratory signals, automated cardiorespiratory metrics, automated respiratory patterns, manually classified respiratory patterns, and manual annotations by clinicians during data acquisition. This MATLAB-based application provides a means for collaborators to view combinations of signals to promote discussion, generate hypotheses and develop features.

A circular model for song motor control in Serinus canaria

PubMed Central

Alonso, Rodrigo G.; Trevisan, Marcos A.; Amador, Ana; Goller, Franz; Mindlin, Gabriel B.

2015-01-01

Song production in songbirds is controlled by a network of nuclei distributed across several brain regions, which drives respiratory and vocal motor systems to generate sound. We built a model for birdsong production, whose variables are the average activities of different neural populations within these nuclei of the song system. We focus on the predictions of respiratory patterns of song, because these can be easily measured and therefore provide a validation for the model. We test the hypothesis that it is possible to construct a model in which (1) the activity of an expiratory related (ER) neural population fits the observed pressure patterns used by canaries during singing, and (2) a higher forebrain neural population, HVC, is sparsely active, simultaneously with significant motor instances of the pressure patterns. We show that in order to achieve these two requirements, the ER neural population needs to receive two inputs: a direct one, and its copy after being processed by other areas of the song system. The model is capable of reproducing the measured respiratory patterns and makes specific predictions on the timing of HVC activity during their production. These results suggest that vocal production is controlled by a circular network rather than by a simple top-down architecture. PMID:25904860

Lung respiratory rhythm and pattern generation in the bullfrog: role of neurokinin-1 and mu-opioid receptors.

PubMed

Davies, B L; Brundage, C M; Harris, M B; Taylor, B E

2009-07-01

Location of the lung respiratory rhythm generator (RRG) in the bullfrog brainstem was investigated by examining neurokinin-1 and mu-opioid receptor (NK1R, muOR) colocalization by immunohistochemistry and characterizing the role of these receptors in lung rhythm and episodic pattern generation. NK1R and muOR occurred in brainstems from all developmental stages. In juvenile bullfrogs a distinct area of colocalization was coincident with high-intensity fluorescent labeling of muOR; high-intensity labeling of muOR was not distinctly and consistently localized in tadpole brainstems. NK1R labeling intensity did not change with development. Similarity in colocalization is consistent with similarity in responses to substance P (SP, NK1R agonist) and DAMGO (muOR agonist) when bath applied to bullfrog brainstems of different developmental stages. In early stage tadpoles and juvenile bullfrogs, SP increased and DAMGO decreased lung burst frequency. In juvenile bullfrogs, SP increased lung burst frequency, episode frequency, but decreased number of lung bursts per episode and lung burst duration. In contrast, DAMGO decreased lung burst frequency and burst cycle frequency, episode frequency, and number of lung bursts per episode but increased all other lung burst parameters. Based on these results, we hypothesize that NK1R and muOR colocalization together with a metamorphosis-related increase in muOR intensity marks the location of the lung RRG but not necessarily the lung episodic pattern generator.

Changes in breathing pattern in the normal horse at rest up to age one year.

PubMed

Koterba, A M; Wozniak, J A; Kosch, P C

1995-07-01

Changes in pattern of airflow, sequence of respiratory muscle activation and generated pressures were measured serially in a group of foals during the first year post partum, in order to describe the maturation of the equine breathing pattern. In neonatal foals, inspiration and expiration were both primarily active and airflow pattern was essentially monophasic. By age 1 year, foals displayed essentially the same breathing pattern previously described in adult horses, utilising a combination of active and passive inspiration and expiration to breathe around, rather than from, the relaxation volume of the respiratory system (Vrx). A strong temporal relationship during growth was found between the timing of changes observed in airflow pattern and in the neuromuscular strategy of breathing. The transition to the adult breathing pattern appeared to involve a time delay in activation of both inspiratory and expiratory muscle groups, establishing a passive and active component to both inspiration and expiration. Throughout the study period, concurrent with the increase in delay of abdominal muscle activation, the expiratory flow pattern became progressively more biphasic in appearance. The time of appearance of a consistent biphasic inspiratory flow pattern was considerably later, at approximately age 1 year and coincided with the appearance of a delay in inspiratory muscle activation. From our results, we conclude that the transition from the neonatal to the adult breathing strategy in the horse appears not to be induced by the time course of chest wall stiffening during maturation. While changes in relative body proportions and size of abdominal contents during growth may influence the transition in breathing, our results also indicate that respiratory control mechanisms play an essential role in the expression of the polyphasic breathing pattern.

Respiratory research networks in Europe and beyond: aims, achievements and aspirations for the 21st century

PubMed Central

Zampieri, Fernando; Povoa, Pedro; Ranzani, Otavio; Bos, Lieuwe D.; Aliberti, Stefano; Torres, Antoni

2017-01-01

Healthcare-associated infection, such as intensive care unit (ICU)-related respiratory infections, remain the most frequently encountered morbidity of ICU admission, prolonging hospital stay and increasing mortality rates. The epidemiology of ICU-related respiratory infections, particularly nonventilated ICU-associated pneumonia and ventilator-associated tracheobronchitis, appears to be quite different among different countries. European countries have different prevalence, patterns and mechanism of resistance, as well as different treatments chosen by different attending physicians. The classical clinical research process in respiratory infections consists of the following loop: 1) identification of knowledge gaps; 2) systematic review and search for adequate answers; 3) generation of study hypotheses; 4) design of study protocols; 5) collection clinical data; 6) analysis and interpretation of the results; and 7) implementation of the results in clinical practice. PMID:28894481

Blockade of brain stem gap junctions increases phrenic burst frequency and reduces phrenic burst synchronization in adult rat.

PubMed

Solomon, Irene C; Chon, Ki H; Rodriguez, Melissa N

2003-01-01

Recent investigations have examined the influence of gap junctional communication on generation and modulation of respiratory rhythm and inspiratory motoneuron synchronization in vitro using transverse medullary slice and en bloc brain stem-spinal cord preparations obtained from neonatal (1-5 days postnatal) mice. Gap junction proteins, however, have been identified in both neurons and glia in brain stem regions implicated in respiratory control in both neonatal and adult rodents. Here, we used an in vitro arterially perfused rat preparation to examine the role of gap junctional communication on generation and modulation of respiratory rhythm and inspiratory motoneuron synchronization in adult rodents. We recorded rhythmic inspiratory motor activity from one or both phrenic nerves before and during pharmacological blockade (i.e., uncoupling) of brain stem gap junctions using carbenoxolone (100 microM), 18alpha-glycyrrhetinic acid (25-100 microM), 18beta-glycyrrhetinic acid (25-100 microM), octanol (200-300 microM), or heptanol (200 microM). During perfusion with a gap junction uncoupling agent, we observed an increase in the frequency of phrenic bursts (~95% above baseline frequency; P < 0.001) and a decrease in peak amplitude of integrated phrenic nerve discharge (P < 0.001). The increase in frequency of phrenic bursts resulted from a decrease in both T(I) (P < 0.01) and T(E) (P < 0.01). In addition, the pattern of phrenic nerve discharge shifted from an augmenting discharge pattern to a "bell-shaped" or square-wave discharge pattern in most experiments. Spectral analyses using a fast Fourier transform (FFT) algorithm revealed a reduction in the peak power of both the 40- to 50-Hz peak (corresponding to the MFO) and 90- to 110-Hz peak (corresponding to the HFO) although spurious higher frequency activity (> or =130 Hz) was observed, suggesting an overall loss or reduction in inspiratory-phase synchronization. Although additional experiments are required to identify the specific brain stem regions and cell types (i.e., neurons, glia) mediating the observed modulations in phrenic motor output, these findings suggest that gap junction communication modulates generation of respiratory rhythm and inspiratory motoneuron synchronization in adult rodents in vitro.

Organization of the core respiratory network: Insights from optogenetic and modeling studies

PubMed Central

John, Tibin T.; Zhang, Ruli; Smith, Jeffrey C.

2018-01-01

The circuit organization within the mammalian brainstem respiratory network, specifically within and between the pre-Bötzinger (pre-BötC) and Bötzinger (BötC) complexes, and the roles of these circuits in respiratory pattern generation are continuously debated. We address these issues with a combination of optogenetic experiments and modeling studies. We used transgenic mice expressing channelrhodopsin-2 under the VGAT-promoter to investigate perturbations of respiratory circuit activity by site-specific photostimulation of inhibitory neurons within the pre-BötC or BötC. The stimulation effects were dependent on the intensity and phase of the photostimulation. Specifically: (1) Low intensity (≤ 1.0 mW) pulses delivered to the pre-BötC during inspiration did not terminate activity, whereas stronger stimulations (≥ 2.0 mW) terminated inspiration. (2) When the pre-BötC stimulation ended in or was applied during expiration, rebound activation of inspiration occurred after a fixed latency. (3) Relatively weak sustained stimulation (20 Hz, 0.5–2.0 mW) of pre-BötC inhibitory neurons increased respiratory frequency, while a further increase of stimulus intensity (> 3.0 mW) reduced frequency and finally (≥ 5.0 mW) terminated respiratory oscillations. (4) Single pulses (0.2–5.0 s) applied to the BötC inhibited rhythmic activity for the duration of the stimulation. (5) Sustained stimulation (20 Hz, 0.5–3.0 mW) of the BötC reduced respiratory frequency and finally led to apnea. We have revised our computational model of pre-BötC and BötC microcircuits by incorporating an additional population of post-inspiratory inhibitory neurons in the pre-BötC that interacts with other neurons in the network. This model was able to reproduce the above experimental findings as well as previously published results of optogenetic activation of pre-BötC or BötC neurons obtained by other laboratories. The proposed organization of pre-BötC and BötC circuits leads to testable predictions about their specific roles in respiratory pattern generation and provides important insights into key circuit interactions operating within brainstem respiratory networks. PMID:29698394

Quantitative Evaluation of PET Respiratory Motion Correction Using MR Derived Simulated Data

NASA Astrophysics Data System (ADS)

Polycarpou, Irene; Tsoumpas, Charalampos; King, Andrew P.; Marsden, Paul K.

2015-12-01

The impact of respiratory motion correction on quantitative accuracy in PET imaging is evaluated using simulations for variable patient specific characteristics such as tumor uptake and respiratory pattern. Respiratory patterns from real patients were acquired, with long quiescent motion periods (type-1) as commonly observed in most patients and with long-term amplitude variability as is expected under conditions of difficult breathing (type-2). The respiratory patterns were combined with an MR-derived motion model to simulate real-time 4-D PET-MR datasets. Lung and liver tumors were simulated with diameters of 10 and 12 mm and tumor-to-background ratio ranging from 3:1 to 6:1. Projection data for 6- and 3-mm PET resolution were generated for the Philips Gemini scanner and reconstructed without and with motion correction using OSEM (2 iterations, 23 subsets). Motion correction was incorporated into the reconstruction process based on MR-derived motion fields. Tumor peak standardized uptake values (SUVpeak) were calculated from 30 noise realizations. Respiratory motion correction improves the quantitative performance with the greatest benefit observed for patients of breathing type-2. For breathing type-1 after applying motion correction, SUVpeak of 12-mm liver tumor with 6:1 contrast was increased by 46% for a current PET resolution (i.e., 6 mm) and by 47% for a higher PET resolution (i.e., 3 mm). Furthermore, the results of this study indicate that the benefit of higher scanner resolution is small unless motion correction is applied. In particular, for large liver tumor (12 mm) with low contrast (3:1) after motion correction, the SUVpeak was increased by 34% for 6-mm resolution and by 50% for a higher PET resolution (i.e., 3-mm resolution. This investigation indicates that there is a high impact of respiratory motion correction on tumor quantitative accuracy and that motion correction is important in order to benefit from the increased resolution of future PET scanners.

4D CT sorting based on patient internal anatomy

NASA Astrophysics Data System (ADS)

Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

2009-08-01

Respiratory motion during free-breathing computed tomography (CT) scan may cause significant errors in target definition for tumors in the thorax and upper abdomen. A four-dimensional (4D) CT technique has been widely used for treatment simulation of thoracic and abdominal cancer radiotherapy. The current 4D CT techniques require retrospective sorting of the reconstructed CT slices oversampled at the same couch position. Most sorting methods depend on external surrogates of respiratory motion recorded by extra instruments. However, respiratory signals obtained from these external surrogates may not always accurately represent the internal target motion, especially when irregular breathing patterns occur. We have proposed a new sorting method based on multiple internal anatomical features for multi-slice CT scan acquired in the cine mode. Four features are analyzed in this study, including the air content, lung area, lung density and body area. We use a measure called spatial coherence to select the optimal internal feature at each couch position and to generate the respiratory signals for 4D CT sorting. The proposed method has been evaluated for ten cancer patients (eight with thoracic cancer and two with abdominal cancer). For nine patients, the respiratory signals generated from the combined internal features are well correlated to those from external surrogates recorded by the real-time position management (RPM) system (average correlation: 0.95 ± 0.02), which is better than any individual internal measures at 95% confidence level. For these nine patients, the 4D CT images sorted by the combined internal features are almost identical to those sorted by the RPM signal. For one patient with an irregular breathing pattern, the respiratory signals given by the combined internal features do not correlate well with those from RPM (correlation: 0.68 ± 0.42). In this case, the 4D CT image sorted by our method presents fewer artifacts than that from the RPM signal. Our 4D CT internal sorting method eliminates the need of externally recorded surrogates of respiratory motion. It is an automatic, accurate, robust, cost efficient and yet simple method and therefore can be readily implemented in clinical settings.

The influence of respiratory motion on CT image volume definition.

PubMed

Rodríguez-Romero, Ruth; Castro-Tejero, Pablo

2014-04-01

Radiotherapy treatments are based on geometric and density information acquired from patient CT scans. It is well established that breathing motion during scan acquisition induces motion artifacts in CT images, which can alter the size, shape, and density of a patient's anatomy. The aim of this work is to examine and evaluate the impact of breathing motion on multislice CT imaging with respiratory synchronization (4DCT) and without it (3DCT). A specific phantom with a movable insert was used. Static and dynamic phantom acquisitions were obtained with a multislice CT. Four sinusoidal breath patterns were simulated to move known geometric structures longitudinally. Respiratory synchronized acquisitions (4DCT) were performed to generate images during inhale, intermediate, and exhale phases using prospective and retrospective techniques. Static phantom data were acquired in helical and sequential mode to define a baseline for each type of respiratory 4DCT technique. Taking into account the fact that respiratory 4DCT is not always available, 3DCT helical image studies were also acquired for several CT rotation periods. To study breath and acquisition coupling when respiratory 4DCT was not performed, the beginning of the CT image acquisition was matched with inhale, intermediate, or exhale respiratory phases, for each breath pattern. Other coupling scenarios were evaluated by simulating different phantom and CT acquisition parameters. Motion induced variations in shape and density were quantified by automatic threshold volume generation and Dice similarity coefficient calculation. The structure mass center positions were also determined to make a comparison with their theoretical expected position. 4DCT acquisitions provided volume and position accuracies within ± 3% and ± 2 mm for structure dimensions >2 cm, breath amplitude ≤ 15 mm, and breath period ≥ 3 s. The smallest object (1 cm diameter) exceeded 5% volume variation for the breath patterns of higher frequency and amplitude motion. Larger volume differences (>10%) and inconsistencies between the relative positions of objects were detected in image studies acquired without respiratory control. Increasing the 3DCT rotation period caused a higher distortion in structures without obtaining their envelope. Simulated data showed that the slice acquisition time should be at least twice the breath period to average object movement. Respiratory 4DCT images provide accurate volume and position of organs affected by breath motion detecting higher volume discrepancies as amplitude length or breath frequency are increased. For 3DCT acquisitions, a CT should be considered slow enough to include lesion envelope as long as the slice acquisition time exceeds twice the breathing period. If this requirement cannot be satisfied, a fast CT (along with breath-hold inhale and exhale CTs to estimate roughly the ITV) is recommended in order to minimize structure distortion. Even with an awareness of a patient's respiratory cycle, its coupling with 3DCT acquisition cannot be predicted since patient anatomy is not accurately known. © 2014 American Association of Physicists in Medicine.

The influence of respiratory motion on CT image volume definition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodríguez-Romero, Ruth, E-mail: rrromero@salud.madrid.org; Castro-Tejero, Pablo, E-mail: pablo.castro@salud.madrid.org

Purpose: Radiotherapy treatments are based on geometric and density information acquired from patient CT scans. It is well established that breathing motion during scan acquisition induces motion artifacts in CT images, which can alter the size, shape, and density of a patient's anatomy. The aim of this work is to examine and evaluate the impact of breathing motion on multislice CT imaging with respiratory synchronization (4DCT) and without it (3DCT). Methods: A specific phantom with a movable insert was used. Static and dynamic phantom acquisitions were obtained with a multislice CT. Four sinusoidal breath patterns were simulated to move knownmore » geometric structures longitudinally. Respiratory synchronized acquisitions (4DCT) were performed to generate images during inhale, intermediate, and exhale phases using prospective and retrospective techniques. Static phantom data were acquired in helical and sequential mode to define a baseline for each type of respiratory 4DCT technique. Taking into account the fact that respiratory 4DCT is not always available, 3DCT helical image studies were also acquired for several CT rotation periods. To study breath and acquisition coupling when respiratory 4DCT was not performed, the beginning of the CT image acquisition was matched with inhale, intermediate, or exhale respiratory phases, for each breath pattern. Other coupling scenarios were evaluated by simulating different phantom and CT acquisition parameters. Motion induced variations in shape and density were quantified by automatic threshold volume generation and Dice similarity coefficient calculation. The structure mass center positions were also determined to make a comparison with their theoretical expected position. Results: 4DCT acquisitions provided volume and position accuracies within ±3% and ±2 mm for structure dimensions >2 cm, breath amplitude ≤15 mm, and breath period ≥3 s. The smallest object (1 cm diameter) exceeded 5% volume variation for the breath patterns of higher frequency and amplitude motion. Larger volume differences (>10%) and inconsistencies between the relative positions of objects were detected in image studies acquired without respiratory control. Increasing the 3DCT rotation period caused a higher distortion in structures without obtaining their envelope. Simulated data showed that the slice acquisition time should be at least twice the breath period to average object movement. Conclusions: Respiratory 4DCT images provide accurate volume and position of organs affected by breath motion detecting higher volume discrepancies as amplitude length or breath frequency are increased. For 3DCT acquisitions, a CT should be considered slow enough to include lesion envelope as long as the slice acquisition time exceeds twice the breathing period. If this requirement cannot be satisfied, a fast CT (along with breath-hold inhale and exhale CTs to estimate roughly the ITV) is recommended in order to minimize structure distortion. Even with an awareness of a patient's respiratory cycle, its coupling with 3DCT acquisition cannot be predicted since patient anatomy is not accurately known.« less

Hierarchy of orofacial rhythms revealed through whisking and breathing

PubMed Central

Moore, Jeffrey D.; Deschênes, Martin; Furuta, Takahiro; Huber, Daniel; Smear, Matthew C.; Demers, Maxime; Kleinfeld, David

2014-01-01

Whisking and sniffing are predominant aspects of exploratory behavior in rodents, yet the neural mechanisms that generate their motor patterns remain largely uncharacterized. We use anatomical, behavioral, electrophysiological, and pharmacological tools to demonstrate that these patterns are coordinated by respiratory centers in the ventral medulla. We delineate a distinct region in the ventral medulla that provides rhythmic input to the facial motoneurons that drive protraction of the vibrissae. Neuronal output from this region is reset at each inspiration by direct input from the preBötzinger complex, such that high frequency sniffing has a one-to-one coordination with whisking while basal respiration is accompanied by intervening whisks that occur between breaths. We conjecture that the respiratory nuclei, which project to other premotor regions for oral and facial control, function as a master clock for behaviors that coordinate with breathing. PMID:23624373

Bursting Transition Dynamics Within the Pre-Bötzinger Complex

NASA Astrophysics Data System (ADS)

Duan, Lixia; Chen, Xi; Tang, Xuhui; Su, Jianzhong

The pre-Bötzinger complex of the mammalian brain stem plays a crucial role in the respiratory rhythms generation. Neurons within the pre-Bötzinger complex have been found experimentally to yield different firing activities. In this paper, we study the spiking and bursting activities related to the respiratory rhythms in the pre-Bötzinger complex based on a mathematical model proposed by Butera. Using the one-dimensional first recurrence map induced by dynamics, we investigate the different bursting patterns and their transition of the pre-Bötzinger complex neurons based on the Butera model, after we derived a one-dimensional map from the dynamical characters of the differential equations, and we obtained conditions for the transition of different bursting patterns. These analytical results were verified through numerical simulations. We conclude that the one-dimensional map contains similar rhythmic patterns as the Butera model and can be used as a simpler modeling tool to study fast-slow models like pre-Bötzinger complex neural circuit.

WE-D-303-02: Applications of Volumetric Images Generated with a Respiratory Motion Model Based On An External Surrogate Signal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurwitz, M; Williams, C; Dhou, S

Purpose: Respiratory motion can vary significantly over the course of simulation and treatment. Our goal is to use volumetric images generated with a respiratory motion model to improve the definition of the internal target volume (ITV) and the estimate of delivered dose. Methods: Ten irregular patient breathing patterns spanning 35 seconds each were incorporated into a digital phantom. Ten images over the first five seconds of breathing were used to emulate a 4DCT scan, build the ITV, and generate a patient-specific respiratory motion model which correlated the measured trajectories of markers placed on the patients’ chests with the motion ofmore » the internal anatomy. This model was used to generate volumetric images over the subsequent thirty seconds of breathing. The increase in the ITV taking into account the full 35 seconds of breathing was assessed with ground-truth and model-generated images. For one patient, a treatment plan based on the initial ITV was created and the delivered dose was estimated using images from the first five seconds as well as ground-truth and model-generated images from the next 30 seconds. Results: The increase in the ITV ranged from 0.2 cc to 6.9 cc for the ten patients based on ground-truth information. The model predicted this increase in the ITV with an average error of 0.8 cc. The delivered dose to the tumor (D95) changed significantly from 57 Gy to 41 Gy when estimated using 5 seconds and 30 seconds, respectively. The model captured this effect, giving an estimated D95 of 44 Gy. Conclusion: A respiratory motion model generating volumetric images of the internal patient anatomy could be useful in estimating the increase in the ITV due to irregular breathing during simulation and in assessing delivered dose during treatment. This project was supported, in part, through a Master Research Agreement with Varian Medical Systems, Inc. and Radiological Society of North America Research Scholar Grant #RSCH1206.« less

Functional Interactions between Mammalian Respiratory Rhythmogenic and Premotor Circuitry

PubMed Central

Song, Hanbing; Hayes, John A.; Vann, Nikolas C.; Wang, Xueying; LaMar, M. Drew

2016-01-01

Breathing in mammals depends on rhythms that originate from the preBötzinger complex (preBötC) of the ventral medulla and a network of brainstem and spinal premotor neurons. The rhythm-generating core of the preBötC, as well as some premotor circuits, consist of interneurons derived from Dbx1-expressing precursors (Dbx1 neurons), but the structure and function of these networks remain incompletely understood. We previously developed a cell-specific detection and laser ablation system to interrogate respiratory network structure and function in a slice model of breathing that retains the preBötC, the respiratory-related hypoglossal (XII) motor nucleus and XII premotor circuits. In spontaneously rhythmic slices, cumulative ablation of Dbx1 preBötC neurons decreased XII motor output by ∼50% after ∼15 cell deletions, and then decelerated and terminated rhythmic function altogether as the tally increased to ∼85 neurons. In contrast, cumulatively deleting Dbx1 XII premotor neurons decreased motor output monotonically but did not affect frequency nor stop XII output regardless of the ablation tally. Here, we couple an existing preBötC model with a premotor population in several topological configurations to investigate which one may replicate the laser ablation experiments best. If the XII premotor population is a “small-world” network (rich in local connections with sparse long-range connections among constituent premotor neurons) and connected with the preBötC such that the total number of incoming synapses remains fixed, then the in silico system successfully replicates the in vitro laser ablation experiments. This study proposes a feasible configuration for circuits consisting of Dbx1-derived interneurons that generate inspiratory rhythm and motor pattern. SIGNIFICANCE STATEMENT To produce a breathing-related motor pattern, a brainstem core oscillator circuit projects to a population of premotor interneurons, but the assemblage of this network remains incompletely understood. Here we applied network modeling and numerical simulation to discover respiratory circuit configurations that successfully replicate photonic cell ablation experiments targeting either the core oscillator or premotor network, respectively. If premotor neurons are interconnected in a so-called “small-world” network with a fixed number of incoming synapses balanced between premotor and rhythmogenic neurons, then our simulations match their experimental benchmarks. These results provide a framework of experimentally testable predictions regarding the rudimentary structure and function of respiratory rhythm- and pattern-generating circuits in the brainstem of mammals. PMID:27383596

Bidirectional plasticity of pontine pneumotaxic postinspiratory drive: implication for a pontomedullary respiratory central pattern generator.

PubMed

Poon, Chi-Sang; Song, Gang

2014-01-01

The "pneumotaxic center" in the rostral dorsolateral pons as delineated by Lumsden nine decades ago is known to play an important role in promoting the inspiratory off-switch (IOS) for inspiratory-expiratory phase transition as a fail-safe mechanism for preventing apneusis in the absence of vagal input. Traditionally, the pontine pneumotaxic mechanism has been thought to contribute a tonic descending input that lowers the IOS threshold in medullary respiratory central pattern generator (rCPG) circuits, but otherwise does not constitute part of the rCPG. Recent evidence indicates that descending input from the Kölliker-Fuse nucleus (KFN) within the pneumotaxic center is essential for gating the postinspiratory phase of the three-phase respiratory rhythm to control the IOS in vagotomized animals. A critical question arising is whether such a descending pneumotaxic input from KFN that drives postinspiratory activity is tonic (null hypothesis) or rhythmic with postinspiratory phase modulation (alternative hypothesis). Here, we show that multifarious evidence reported in the literature collectively indicates that the descending pneumotaxic input may exhibit NMDA receptor-dependent short-term plasticity in the form of a biphasic neural differentiator that bidirectionally and phase-selectively modulates postinspiratory phase duration in response to vagal and peripheral chemoreceptor inputs independent of the responses in inspiratory and late-expiratory activities. The phase-selectivity property of the descending pneumotaxic input implicates a population of pontine early-expiratory (postinspiratory/expiratory-decrementing) neurons as the most likely neural correlate of the pneumotaxic mechanism that drives post-I activity, suggesting that the pontine pneumotaxic mechanism may be an integral part of a pontomedullary rCPG that underlies the three-phase respiratory rhythm. © 2014 Elsevier B.V. All rights reserved.

Metabotropic glutamate receptors activate dendritic calcium waves and TRPM channels which drive rhythmic respiratory patterns in mice

PubMed Central

Mironov, S L

2008-01-01

Respiration in vertebrates is generated by a compact network which is located in the lower brainstem but cellular mechanisms which underlie persistent oscillatory activity of the respiratory network are yet unknown. Using two-photon imaging and patch-clamp recordings in functional brainstem preparations of mice containing pre-Bötzinger complex (preBötC), we examined the actions of metabotropic glutamate receptors (mGluR1/5) on the respiratory patterns. The agonist DHPG potentiated and antagonist LY367385 depressed respiration-related activities. In the inspiratory neurons, we observed rhythmic activation of non-selective channels which had a conductance of 24 pS. Their activity was enhanced with membrane depolarization and after elevation of calcium from the cytoplasmic side of the membrane. They were activated by a non-hydrolysable PIP2 analogue and blocked by flufenamate, ATP4− and Gd3+. All these properties correspond well to those of TRPM4 channels. Calcium imaging of functional slices revealed rhythmic transients in small clusters of neurons present in a network. Calcium transients in the soma were preceded by the waves in dendrites which were dependent on mGluR activation. Initiation and propagation of waves required calcium influx and calcium release from internal stores. Calcium waves activated TPRM4-like channels in the soma and promoted generation of inspiratory bursts. Simulations of activity of neurons communicated via dendritic calcium waves showed emerging activity within neuronal clusters and its synchronization between the clusters. The experimental and theoretical data provide a subcellular basis for a recently proposed group-pacemaker hypothesis and describe a novel mechanism of rhythm generation in neuronal networks. PMID:18308826

Interactive simulation system for artificial ventilation on the internet: virtual ventilator.

PubMed

Takeuchi, Akihiro; Abe, Tadashi; Hirose, Minoru; Kamioka, Koichi; Hamada, Atsushi; Ikeda, Noriaki

2004-12-01

To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.

Pharmacology of Vagal Afferent Influences on Disordered Breathing During Sleep

PubMed Central

Carley, David W; Radulovacki, Miodrag

2008-01-01

Sleep related breathing disorders (SRBD) are a significant public health concern, with a prevalence in the US general population of ∼2% of women and ∼4% of men. Although significant strides have been made in our understanding of these disorders with respect to epidemiology, risk factors, pathogenesis and consequences, work to understand these factors in terms of the underlying cellular, molecular and neuromodulatory processes remains in its infancy. Current primary treatments are surgical or mechanical, with no drug treatments available. Basic investigations into the neurochemistry and neuropharmacology of sleep-related changes in respiratory pattern generation and modulation will be essential to clarify the pathogenic processes underlying SRBD and to identify rational and specific pharmacotherapeutic opportunities. Here we summarize emerging work suggesting the importance of vagal afferent feedback systems in sleep related respiratory pattern disturbances and pointing toward a rich but complex array of neurochemical and neuromodulatory processes that may be involved. PMID:18694851

Pattern of deposition of stainless steel welding fume particles inhaled into the respiratory systems of Sprague-Dawley rats exposed to a novel welding fume generating system.

PubMed

Yu, I J; Kim, K J; Chang, H K; Song, K S; Han, K T; Han, J H; Maeng, S H; Chung, Y H; Park, S H; Chung, K H; Han, J S; Chung, H K

2000-07-27

In order to investigate occupational diseases related to welding fume exposure, such as nasal septum perforation, pneumoconiosis and manganese intoxication, we built a welding fume exposure system that included a welding fume generator, exposure chamber and fume collector. The fume concentrations in the exposure chamber were monitored every 15 min during a 2-h exposure. Fume (mg/m(3)) concentrations of major metals, including Fe, Mn, Cr, and Ni were found to be consistently maintained. An acute inhalation toxicity study was conducted by exposing male Sprague-Dawley rats to the welding fumes generated in this apparatus by stainless steel arc welding. The rats were exposed in the inhalation chamber to a welding fume with a concentration of 62 mg/m(3) total suspended particulates for 4 h. Animals were sacrificed at 4 h and at 1, 3, 7, 10, and 14 days after exposure. Histopathological examinations were conducted on the animals' upper respiratory tracts, including the nasal pathway and the conducting airway, and on the gas exchange region including the alveolar ducts, alveolar sacs, and alveoli. Diameters of fume particles varied from 0.02 to 0.81 microm and were distributed log normally, with a mean diameter of 0.1 microm and geometric standard deviation of 1.42. Rats exposed to the welding fume for 4 h did not show any significant respiratory system toxicity. The mean particle diameter of 0.1 microm resulted in little adsorption of the welding fume particles in the upper respiratory tract. Particle adsorption took place principally in the lower respiratory tracts, including bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Postnatal developmental changes in activation profiles of the respiratory neuronal network in the rat ventral medulla

PubMed Central

Oku, Yoshitaka; Masumiya, Haruko; Okada, Yasumasa

2007-01-01

Two putative respiratory rhythm generators (RRGs), the para-facial respiratory group (pFRG) and the pre-Bötzinger complex (preBötC), have been identified in the neonatal rodent brainstem. To elucidate their functional roles during the neonatal period, we evaluated developmental changes of these RRGs by optical imaging using a voltage-sensitive dye. Optical signals, recorded from the ventral medulla of brainstem–spinal cord preparations of neonatal (P0–P4) rats (n = 44), were analysed by a cross correlation method. With development during the first few postnatal days, the respiratory-related activity in the pFRG reduced and shifted from a preinspiratory (P0–P1) to an inspiratory (P2–P4) pattern, whereas preBötC activity remained unchanged. The μ-opioid agonist [d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO) augmented preinspiratory activity in the pFRG, while the μ-opioid antagonist naloxone induced changes in spatiotemporal activation profiles that closely mimicked the developmental changes. These results are consistent with the recently proposed hypothesis by Janczewski and Feldman that the pFRG is activated to compensate for the depression of the preBötC by perinatal opiate surge. We conclude that significant reorganization of the respiratory neuronal network, characterized by a reduction of preinspiratory activity in the pFRG, occurs at P1–P2 in rats. The changes in spatiotemporal activation profiles of the pFRG neurones may reflect changes in the mode of coupling of the two respiratory rhythm generators. PMID:17884928

Prognosis in Acute Cerebrovascular Accidents in Relation to Respiratory Pattern and Blood—gas Tensions

PubMed Central

Rout, M. W.; Lane, D. J.; Wollner, L.

1971-01-01

Respiratory pattern and arterial blood gas tensions were assessed in patients with acute cerebrovascular accidents. Hyperventilation, low Pco2, and high arterial pH were associated with a poor prognosis, whereas patients with normal respiratory pattern and blood gas tensions survived. Periodic and Cheyne-Stokes breathing carried an intermediate prognosis. PMID:5091916

Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification.

PubMed

Wang, Shouyi; Bowen, Stephen R; Chaovalitwongse, W Art; Sandison, George A; Grabowski, Thomas J; Kinahan, Paul E

2014-02-21

The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUV(peak)) over lesions of interest. Relative differences in SUV(peak) between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUV(peak) values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion compensation when clinicians quantitatively assess PET/CT for therapy target definition and response assessment.

Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

NASA Astrophysics Data System (ADS)

Wang, Shouyi; Bowen, Stephen R.; Chaovalitwongse, W. Art; Sandison, George A.; Grabowski, Thomas J.; Kinahan, Paul E.

2014-02-01

The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUVpeak) over lesions of interest. Relative differences in SUVpeak between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUVpeak values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion compensation when clinicians quantitatively assess PET/CT for therapy target definition and response assessment.

Substance P modulation of TRPC3/7 channels improves respiratory rhythm regularity and ICAN-dependent pacemaker activity

PubMed Central

Ben-Mabrouk, Faiza; Tryba, Andrew Kieran

2011-01-01

Neuromodulators, such as Substance P (SubP) play an important role in modulating many rhythmic activities driven by central pattern generators (e.g., locomotion, respiration). However, the mechanism by which SubP enhances breathing regularity has not been determined. Here, we used mouse brainstem slices containing the pre-Bötzinger Complex (Pre-BötC) to demonstrate, for the first time, that SubP activates transient receptor protein canonical (TRPC) channels to enhance respiratory rhythm regularity. Moreover, SubP enhancement of network regularity is accomplished via selective enhancement of ICAN-dependent intrinsic bursting properties. In contrast to INaP-dependant pacemakers, ICAN-dependant pacemaker bursting activity is TRPC dependent. Western Blots reveal TRPC3 and TRPC7 channels are expressed in rhythmically active ventral respiratory group (VRG) island preparations. Taken together, these data suggest that SubP-mediated activation of TRPC3/7 channels underlies rhythmic ICAN-dependent pacemaker activity and enhances the regularity of respiratory rhythm activity. PMID:20345918

Substance P modulation of TRPC3/7 channels improves respiratory rhythm regularity and ICAN-dependent pacemaker activity.

PubMed

Ben-Mabrouk, Faiza; Tryba, Andrew K

2010-04-01

Neuromodulators, such as substance P (SubP), play an important role in modulating many rhythmic activities driven by central pattern generators (e.g. locomotion, respiration). However, the mechanism by which SubP enhances breathing regularity has not been determined. Here, we used mouse brainstem slices containing the pre-Bötzinger complex to demonstrate, for the first time, that SubP activates transient receptor protein canonical (TRPC) channels to enhance respiratory rhythm regularity. Moreover, SubP enhancement of network regularity is accomplished via selective enhancement of ICAN (inward non-specific cation current)-dependent intrinsic bursting properties. In contrast to INaP (persistent sodium current)-dependent pacemakers, ICAN-dependent pacemaker bursting activity is TRPC-dependent. Western Blots reveal TRPC3 and TRPC7 channels are expressed in rhythmically active ventral respiratory group island preparations. Taken together, these data suggest that SubP-mediated activation of TRPC3/7 channels underlies rhythmic ICAN-dependent pacemaker activity and enhances the regularity of respiratory rhythm activity.

Evidence and control of bifurcations in a respiratory system.

PubMed

Goldin, Matías A; Mindlin, Gabriel B

2013-12-01

We studied the pressure patterns used by domestic canaries in the production of birdsong. Acoustically different sound elements ("syllables") were generated by qualitatively different pressure gestures. We found that some ubiquitous transitions between syllables can be interpreted as bifurcations of a low dimensional dynamical system. We interpreted these results as evidence supporting a model in which different timescales interact nonlinearly.

Evidence and control of bifurcations in a respiratory system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldin, Matías A., E-mail: mgoldin@df.uba.ar; Mindlin, Gabriel B.

2013-12-15

We studied the pressure patterns used by domestic canaries in the production of birdsong. Acoustically different sound elements (“syllables”) were generated by qualitatively different pressure gestures. We found that some ubiquitous transitions between syllables can be interpreted as bifurcations of a low dimensional dynamical system. We interpreted these results as evidence supporting a model in which different timescales interact nonlinearly.

Maintaining a Distinction Between Possible and Impossible Topics of Conversation in the Outpatient Respiratory Medical Clinic

PubMed Central

Jensen, Lone Birgitte Skov; Larsen, Kristian; Konradsen, Hanne

2016-01-01

The aim of this study is to generate a grounded theory explaining patterns of behavior among health care professionals (HCPs) during interactions with patients in outpatient respiratory medical clinics. The findings suggest that the HCPs managed contradictory expectations to the interaction by maintaining a distinction between possible and impossible topics to counseling. Three subcategories explaining the effort that maintain the impossible and possible topics separated were identified: (a) an effort to maintain the diseased lungs as the main task in counseling, (b) navigating interactions to avoid strong emotions of suffering in patients to reveal, (c) avoiding the appearance of the non-alterable life circumstances of the patients. The HCPs’ attitudes toward what patients could be offered generated a distance and a difficulty during counseling and created further suffering in the patients but likewise a discomfort and frustration among the HCPs. PMID:28462333

Maintaining a Distinction Between Possible and Impossible Topics of Conversation in the Outpatient Respiratory Medical Clinic.

PubMed

Jensen, Lone Birgitte Skov; Larsen, Kristian; Konradsen, Hanne

2016-01-01

The aim of this study is to generate a grounded theory explaining patterns of behavior among health care professionals (HCPs) during interactions with patients in outpatient respiratory medical clinics. The findings suggest that the HCPs managed contradictory expectations to the interaction by maintaining a distinction between possible and impossible topics to counseling. Three subcategories explaining the effort that maintain the impossible and possible topics separated were identified: (a) an effort to maintain the diseased lungs as the main task in counseling, (b) navigating interactions to avoid strong emotions of suffering in patients to reveal, (c) avoiding the appearance of the non-alterable life circumstances of the patients. The HCPs' attitudes toward what patients could be offered generated a distance and a difficulty during counseling and created further suffering in the patients but likewise a discomfort and frustration among the HCPs.

Pacifier Stiffness Alters the Dynamics of the Suck Central Pattern Generator.

PubMed

Zimmerman, Emily; Barlow, Steven M

2008-06-01

Variation in pacifier stiffness on non-nutritive suck (NNS) dynamics was examined among infants born prematurely with a history of respiratory distress syndrome. Three types of silicone pacifiers used in the NICU were tested for stiffness, revealing the Super Soothie™ nipple is 7 times stiffer than the Wee™ or Soothie™ pacifiers even though shape and displaced volume are identical. Suck dynamics among 20 preterm infants were subsequently sampled using the Soothie™ and Super Soothie™ pacifiers during follow-up at approximately 3 months of age. ANOVA revealed significant differences in NNS cycles/min, NNS amplitude, NNS cycles/burst, and NNS cycle periods as a function of pacifier stiffness. Infants modify the spatiotemporal output of their suck central pattern generator when presented with pacifiers with significantly different mechanical properties. Infants show a non-preference to suck due to high stiffness in the selected pacifier. Therefore, excessive pacifier stiffness may decrease ororhythmic patterning and impact feeding outcomes.

Pacifier Stiffness Alters the Dynamics of the Suck Central Pattern Generator

PubMed Central

Zimmerman, Emily; Barlow, Steven M.

2008-01-01

Variation in pacifier stiffness on non-nutritive suck (NNS) dynamics was examined among infants born prematurely with a history of respiratory distress syndrome. Three types of silicone pacifiers used in the NICU were tested for stiffness, revealing the Super Soothie™ nipple is 7 times stiffer than the Wee™ or Soothie™ pacifiers even though shape and displaced volume are identical. Suck dynamics among 20 preterm infants were subsequently sampled using the Soothie™ and Super Soothie™ pacifiers during follow-up at approximately 3 months of age. ANOVA revealed significant differences in NNS cycles/min, NNS amplitude, NNS cycles/burst, and NNS cycle periods as a function of pacifier stiffness. Infants modify the spatiotemporal output of their suck central pattern generator when presented with pacifiers with significantly different mechanical properties. Infants show a non-preference to suck due to high stiffness in the selected pacifier. Therefore, excessive pacifier stiffness may decrease ororhythmic patterning and impact feeding outcomes. PMID:19492006

A Randomized Clinical Trial Comparing the Effects of Antitussive Agents on Respiratory Center Output in Patients With Chronic Cough.

PubMed

Mannini, Claudia; Lavorini, Federico; Zanasi, Alessandro; Saibene, Federico; Lanata, Luigi; Fontana, Giovanni

2017-06-01

Cough is produced by the same neuronal pool implicated in respiratory rhythm generation, and antitussive drugs acting at the central level, such as opioids, may depress ventilation. Levodropropizine is classified as a nonopioid peripherally acting antitussive drug that acts at the level of airway sensory nerves. However, the lack of a central action by levodropropizine remains to be fully established. We set out to compare the effects of levodropropizine and the opioid antitussive agent dihydrocodeine on the respiratory responses to a conventional CO 2 rebreathing test in patients with chronic cough of any origin. Twenty-four outpatients (aged 39-70 years) with chronic cough were studied. On separate runs, each patient was randomly administered 60 mg levodropropizine, 15 mg dihydrocodeine, or a matching placebo. Subsequently, patients breathed a mixture of 93% oxygen and 7% CO 2 for 5 min. Fractional end-tidal CO 2 (Fetco 2 ) and inspiratory minute ventilation (V˙i) were continuously monitored. Changes in breathing pattern variables were also assessed. At variance with dihydrocodeine, levodropropizine and placebo did not affect respiratory responses to hypercapnia (P < .01). The ventilatory increases by hypercapnia were mainly accounted for by a rise in the volume components of the breathing pattern. The results are consistent with a peripheral action by levodropropizine; the assessment of ventilatory responses to CO 2 may represent a useful tool to investigate the central respiratory effects of antitussive agents. European Union Clinical Trials Register (EudraCT No.: 2013-004735-68); URL: https://www.clinicaltrialsregister.eu/. Copyright © 2017. Published by Elsevier Inc.

Assessment of human respiration patterns via noncontact sensing using Doppler multi-radar system.

PubMed

Gu, Changzhan; Li, Changzhi

2015-03-16

Human respiratory patterns at chest and abdomen are associated with both physical and emotional states. Accurate measurement of the respiratory patterns provides an approach to assess and analyze the physical and emotional states of the subject persons. Not many research efforts have been made to wirelessly assess different respiration patterns, largely due to the inaccuracy of the conventional continuous-wave radar sensor to track the original signal pattern of slow respiratory movements. This paper presents the accurate assessment of different respiratory patterns based on noncontact Doppler radar sensing. This paper evaluates the feasibility of accurately monitoring different human respiration patterns via noncontact radar sensing. A 2.4 GHz DC coupled multi-radar system was used for accurate measurement of the complete respiration patterns without any signal distortion. Experiments were carried out in the lab environment to measure the different respiration patterns when the subject person performed natural breathing, chest breathing and diaphragmatic breathing. The experimental results showed that accurate assessment of different respiration patterns is feasible using the proposed noncontact radar sensing technique.

Assessment of Human Respiration Patterns via Noncontact Sensing Using Doppler Multi-Radar System

PubMed Central

Gu, Changzhan; Li, Changzhi

2015-01-01

Human respiratory patterns at chest and abdomen are associated with both physical and emotional states. Accurate measurement of the respiratory patterns provides an approach to assess and analyze the physical and emotional states of the subject persons. Not many research efforts have been made to wirelessly assess different respiration patterns, largely due to the inaccuracy of the conventional continuous-wave radar sensor to track the original signal pattern of slow respiratory movements. This paper presents the accurate assessment of different respiratory patterns based on noncontact Doppler radar sensing. This paper evaluates the feasibility of accurately monitoring different human respiration patterns via noncontact radar sensing. A 2.4 GHz DC coupled multi-radar system was used for accurate measurement of the complete respiration patterns without any signal distortion. Experiments were carried out in the lab environment to measure the different respiration patterns when the subject person performed natural breathing, chest breathing and diaphragmatic breathing. The experimental results showed that accurate assessment of different respiration patterns is feasible using the proposed noncontact radar sensing technique. PMID:25785310

The Cellular Building Blocks of Breathing

PubMed Central

Ramirez, J.M.; Doi, A.; Garcia, A.J.; Elsen, F.P.; Koch, H.; Wei, A.D.

2013-01-01

Respiratory brainstem neurons fulfill critical roles in controlling breathing: they generate the activity patterns for breathing and contribute to various sensory responses including changes in O2 and CO2. These complex sensorimotor tasks depend on the dynamic interplay between numerous cellular building blocks that consist of voltage-, calcium-, and ATP-dependent ionic conductances, various ionotropic and metabotropic synaptic mechanisms, as well as neuromodulators acting on G-protein coupled receptors and second messenger systems. As described in this review, the sensorimotor responses of the respiratory network emerge through the state-dependent integration of all these building blocks. There is no known respiratory function that involves only a small number of intrinsic, synaptic, or modulatory properties. Because of the complex integration of numerous intrinsic, synaptic, and modulatory mechanisms, the respiratory network is capable of continuously adapting to changes in the external and internal environment, which makes breathing one of the most integrated behaviors. Not surprisingly, inspiration is critical not only in the control of ventilation, but also in the context of “inspiring behaviors” such as arousal of the mind and even creativity. Far-reaching implications apply also to the underlying network mechanisms, as lessons learned from the respiratory network apply to network functions in general. PMID:23720262

Central cholinergic regulation of respiration: nicotinic receptors

PubMed Central

Shao, Xuesi M; Feldman, Jack L

2009-01-01

Nicotinic acetylcholine receptors (nAChRs) are expressed in brainstem and spinal cord regions involved in the control of breathing. These receptors mediate central cholinergic regulation of respiration and effects of the exogenous ligand nicotine on respiratory pattern. Activation of α4* nAChRs in the preBötzinger Complex (preBötC), an essential site for normal respiratory rhythm generation in mammals, modulates excitatory glutamatergic neurotransmission and depolarizes preBötC inspiratory neurons, leading to increases in respiratory frequency. nAChRs are also present in motor nuclei innervating respiratory muscles. Activation of post- and/or extra-synaptic α4* nAChRs on hypoglossal (XII) motoneurons depolarizes these neurons, potentiating tonic and respiratory-related rhythmic activity. As perinatal nicotine exposure may contribute to the pathogenesis of sudden infant death syndrome (SIDS), we discuss the effects of perinatal nicotine exposure on development of the cholinergic and other neurotransmitter systems involved in control of breathing. Advances in understanding of the mechanisms underlying central cholinergic/nicotinic modulation of respiration provide a pharmacological basis for exploiting nAChRs as therapeutic targets for neurological disorders related to neural control of breathing such as sleep apnea and SIDS. PMID:19498418

Respiratory and metabolic acidosis differentially affect the respiratory neuronal network in the ventral medulla of neonatal rats.

PubMed

Okada, Yasumasa; Masumiya, Haruko; Tamura, Yoshiyasu; Oku, Yoshitaka

2007-11-01

Two respiratory-related areas, the para-facial respiratory group/retrotrapezoid nucleus (pFRG/RTN) and the pre-Bötzinger complex/ventral respiratory group (preBötC/VRG), are thought to play key roles in respiratory rhythm. Because respiratory output patterns in response to respiratory and metabolic acidosis differ, we hypothesized that the responses of the medullary respiratory neuronal network to respiratory and metabolic acidosis are different. To test these hypotheses, we analysed respiratory-related activity in the pFRG/RTN and preBötC/VRG of the neonatal rat brainstem-spinal cord in vitro by optical imaging using a voltage-sensitive dye, and compared the effects of respiratory and metabolic acidosis on these two populations. We found that the spatiotemporal responses of respiratory-related regional activities to respiratory and metabolic acidosis are fundamentally different, although both acidosis similarly augmented respiratory output by increasing respiratory frequency. PreBötC/VRG activity, which is mainly inspiratory, was augmented by respiratory acidosis. Respiratory-modulated pixels increased in the preBötC/VRG area in response to respiratory acidosis. Metabolic acidosis shifted the respiratory phase in the pFRG/RTN; the pre-inspiratory dominant pattern shifted to inspiratory dominant. The responses of the pFRG/RTN activity to respiratory and metabolic acidosis are complex, and involve either augmentation or reduction in the size of respiratory-related areas. Furthermore, the activation pattern in the pFRG/RTN switched bi-directionally between pre-inspiratory/inspiratory and post-inspiratory. Electrophysiological study supported the results of our optical imaging study. We conclude that respiratory and metabolic acidosis differentially affect activities of the pFRG/RTN and preBötC/VRG, inducing switching and shifts of the respiratory phase. We suggest that they differently influence the coupling states between the pFRG/RTN and preBötC/VRG.

[Respiratory infections caused by metapneumovirus in elderly patients].

PubMed

Fica C, Alberto; Hernández C, Loreto; Porte T, Lorena; Castro S, Marcelo; Weitzel, Thomas

2011-04-01

Human metapneumovirus infections are increasingly recognized among adult patients and the aim of this report is to present a series of 4 cases admitted during the winter of 2010. All were detected by direct fluorescence anti-bodies assay of respiratory samples and all were female patients with an age range of 79 to 95 years, including two bedridden cases, one with dementia and three with chronic obstructive pulmonary disease. One patient presented with parainfluenza 3 virus coinfection. Patients presented with pneumonía in 3 cases (interstitial pattern in 2 and lobar consolidation in the other) or acute exacerbation of chronic bronchitis in the remaining case. Symptoms were present for 3 to 7 days before admission and 3 have wheezing. All had hypoxemic or global respiratory failure and lymphopenia (< 1.000/mm³). Hospitalization lasted for 5 to 20 days, marked in the 3 cases that survived by prolonged bronchial obstructive manifestations. Two cases required non invasive mechanical ventilation. Human metapneumovirus infections can decompensate elderly patients with chronic respiratory diseases generating hospital admission and a prolonged morbidity marked by obstructive manifestations and sometimes can become into death.

The control effect of histamine on body temperature and respiratory function in IgE-dependent systemic anaphylaxis.

PubMed

Makabe-Kobayashi, Yoko; Hori, Yoshio; Adachi, Tetsuya; Ishigaki-Suzuki, Satsuki; Kikuchi, Yoshihiro; Kagaya, Yutaka; Shirato, Kunio; Nagy, András; Ujike, Azusa; Takai, Toshiyuki; Watanabe, Takehiko; Ohtsu, Hiroshi

2002-08-01

The systemic anaphylaxis reaction comprises various symptoms, including hypotension, changes in respiration pattern, and hypothermia. To elucidate the role of histamine in each of these symptoms, we induced the passive systemic anaphylaxis reaction in histidine decarboxylase gene knockout (HDC [-/-]) mice, which lack histamine. HDC(-/-) mice were generated by knocking out the HDC gene, which codes for the unique histamine-synthesizing enzyme. Twenty-four hours after the injection of IgE, HDC(+/+) and HDC(-/-) mice were injected with allergen and body temperature, blood pressure, and respiratory function were monitored in each mouse. Blood pressure dropped in both the HDC(-/-) mice and the HDC(+/+) mice. In contrast, respiratory frequency dropped and the expiratory respiration time was elongated only in the HDC(+/+) mice. Body temperature was decreased in the HDC(+/+) mice and was practically unchanged in the HDC(-/-) mice. Histamine receptor antagonists blocked the body temperature drop in the HDC(+/+) mice. Intravenous histamine induced similar patterns of body temperature decrease in the HDC(+/+) mice and the HDC(-/-) mice. Mast cell-deficient W/W (v) mice did not show the decrease in body temperature; this suggests that the histamine that contributed to the decrease in body temperature was derived from mast cells. According to the results of this investigation, in the passive systemic anaphylaxis reaction, respiratory frequency, expiratory time, and body temperature are shown to be controlled by the activity of histamine, but its contribution to blood pressure is negligible.

Pathogens, patterns of pneumonia, and epidemiologic risk factors associated with respiratory disease in recently weaned cattle in Ireland.

PubMed

Murray, Gerard M; More, Simon J; Sammin, Dónal; Casey, Mìcheàl J; McElroy, Máire C; O'Neill, Rónan G; Byrne, William J; Earley, Bernadette; Clegg, Tracy A; Ball, Hywel; Bell, Colin J; Cassidy, Joseph P

2017-01-01

We examined the pathogens, morphologic patterns, and risk factors associated with bovine respiratory disease (BRD) in 136 recently weaned cattle ("weanlings"), 6-12 mo of age, that were submitted for postmortem examination to regional veterinary laboratories in Ireland. A standardized sampling protocol included routine microbiologic investigations as well as polymerase chain reaction and immunohistochemistry. Lungs with histologic lesions were categorized into 1 of 5 morphologic patterns of pneumonia. Fibrinosuppurative bronchopneumonia (49%) and interstitial pneumonia (48%) were the morphologic patterns recorded most frequently. The various morphologic patterns of pulmonary lesions suggest the involvement of variable combinations of initiating and compounding infectious agents that hindered any simple classification of the etiopathogenesis of the pneumonias. Dual infections were detected in 58% of lungs, with Mannheimia haemolytica and Histophilus somni most frequently recorded in concert. M. haemolytica (43%) was the most frequently detected respiratory pathogen; H. somni was also shown to be frequently implicated in pneumonia in this age group of cattle. Bovine parainfluenza virus 3 (BPIV-3) and Bovine respiratory syncytial virus (16% each) were the viral agents detected most frequently. Potential respiratory pathogens (particularly Pasteurella multocida, BPIV-3, and H. somni) were frequently detected (64%) in lungs that had neither gross nor histologic pulmonary lesions, raising questions regarding their role in the pathogenesis of BRD. The breadth of respiratory pathogens detected in bovine lungs by various detection methods highlights the diagnostic value of parallel analyses in respiratory disease postmortem investigation.

[Characteristics of auto-CPAP devices during the simulation of sleep-related breathing flow patterns].

PubMed

Rühle, K H; Karweina, D; Domanski, U; Nilius, G

2009-07-01

The function of automatic CPAP devices is difficult to investigate using clinical examinations due to the high variability of breathing disorders. With a flow generator, however, identical breathing patterns can be reproduced so that comparative studies on the behaviour of pressure of APAP devices are possible. Because the algorithms of APAP devices based on the experience of users can be modified without much effort, also previously investigated devices should regularly be reviewed with regard to programme changes. Had changes occurred in the algorithms of 3 selected devices--compared to the previously published benchmark studies? Do the current versions of these investigated devices differentiate between open and closed apnoeas? With a self-developed respiratory pump, sleep-related breathing patterns and, with the help of a computerised valve, resistances of the upper respiratory tract were simulated. Three different auto-CPAP devices were subjected to a bench test with and without feedback (open/closed loop). Open loop: the 3 devices showed marked differences in the rate of pressure rise but did not differ from the earlier published results. From an initial pressure of 4 mbar the pressure increased to 10 mbar after a different number of apnoeas (1-6 repetitive apnoeas). Only one device differentiated between closed and open apnoeas. Closed loop: due to the pressure increase, the flow generator simulated reduced obstruction of the upper airways (apnoeas changed to hypopnoeas, hypopnoeas changed to flattening) but different patterns of pressure regulation could still be observed. By applying bench-testing, the algorithms of auto-CPAP devices can regularly be reviewed to detect changes in the software. The differentiation between open and closed apnoeas should be improved in several APAP devices.

[Disturbed respiratory cycle accompanying hypoxic-ischemic encephalopathy].

PubMed

Saito, Yoshiaki; Masuko, Kaori; Kaneko, Kaori; Saito, Kazuyo; Chikumaru, Yuri; Iwamoto, Hiroko; Matsui, Akira; Kimura, Seiji

2005-09-01

We report the case of a 2-year-old boy who experienced total asphyxia at 4 months of age, and suffered abnormalities at specific phases of the respiratory cycle. The patient was bedridden due to severe tetraplegia and showed little response to external stimuli. He has been tube-fed since the initial asphyxia and a tracheotomy was performed after recurrent hypoxic episodes as a result of the respiratory dysfunction. Upon examination, his respiratory pattern was characterized by arrest during the inspiratory phase with a possible over-riding secondary inspiration. The respiratory pause at the inspiratory phase was markedly prolonged during an episode of pulmonary infection, resulting in recurrent cyanosis that necessitated artificial ventilation. The "second" inspiration typically occurred during the mid- or late-inspiratory phases, with this pattern often shown to be variable after epileptic seizures. The characteristic breathing of this patient suggested that difficulty in forming a normal respiratory cycle, other than during periods of hypoventilation or apnoea, could be a significant respiratory dysfunction following asphyxiation. Strategies for the management of such patients should be carefully designed after close observation of breathing patterns within the respiratory cycle, and with consideration for the influence of epileptic seizures and other inputs from somatic afferents.

Respiratory Patterns in Students Enrolled in Schools for Disruptive Behaviour before, during, and after "Yoga Nidra" Relaxation

ERIC Educational Resources Information Center

Jensen, P. S.; Stevens, P. J.; Kenny, D. T.

2012-01-01

This study investigated the effects of one session of "Yoga Nidra" (relaxation technique) on the breathing patterns/respiratory effort in the thoracic and abdominal chest regions of boys with disruptive behaviour using a Respiratory Inductive Plethysmography (RIP). The participants (n = 7) were aged 10-15 years and attending NSW, Department of…

SU-F-T-634: Feasibility Study of Respiratory Gated RapidArc SBRT Using a 6MV FFF Photon Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dou, K; Safaraz, M; Rodgers, J

Purpose: To conduct a feasibility study on retrospective respiratory gating and marker tracking for lung stereotactic body radiotherapy (SBRT) with a gated RapidArc delivery using a 6MV flattened filter free photon mode. Methods: A CIRS dynamic thorax phantom Model 008A with different inserts was used for treatment planning and respiratory gating. 4D CT had a free breathing simulation followed by a respiration gated, ten phased CT using a Philips Brilliance CT with a Varian RPM respiratory gating system. The internal target volume was created from the ten phase gated CT images, followed by exporting to a Varian Eclipse TPS v11more » for treatment planning on the free breath images. Both MIP and AIP were also generated for comparison of planning and target motion tracking. The planned dose was delivered with a 6MV FFF photon beam from a Varian TrueBeam accelerator. Gated target motion was also verified by tracking the implanted makers during delivery using continuous kV imaging in addition to CBCT, kV and MV localization and verification. Results: Gating was studied in three situations of lower, normal, and faster breathing at a respiratory cycle of 5, 15 and 25 breaths per minute, respectively. 4D treatment planning was performed at a normal breathing of 15 breaths per minute. The gated patterns obtained using the TrueBeam IR camera were compared with the planned ones while gating operation was added prior to delivery . Gating was realized only when the measured respiratory patterns matched to the planned ones. The gated target motion was verified within the tolerance by kV and MV imaging. Either free breathing CT or averaged CT images were studied to be good for image guidance to align the target. Conclusion: Gated RapidArc SBRT delivered with a 6MV FFF photon beam is realized using a dynamic lung phantom.« less

The effect of ambient humidity and metabolic rate on the gas-exchange pattern of the semi-aquatic insect Aquarius remigis.

PubMed

Contreras, Heidy L; Bradley, Timothy J

2011-04-01

We have examined the effects of temperature on metabolic rate and respiratory pattern in the water strider Aquarius remigis. As temperature was increased from 10 to 30°C, the metabolic rate of the insects increased and the respiratory pattern transitioned from discontinuous, to cyclic, to continuous. The discontinuous gas-exchange cycle (DGC) was observed even in insects standing on water when the respirometry chamber was being perfused with humid (>95% relative humidity) air. Comparisons of insects at 20°C in humid and dry air showed no statistically significant differences in metabolic rate or respiratory pattern (P>0.05). The proportion of time that the spiracles were closed was greater at 10°C than at 20°C (P<0.01), and greater at 20°C than at 30°C (P<0.05). These results are compatible with the hypothesis that the respiratory patterns of insects are determined by the relationship between oxygen supply and oxygen demand. There was no evidence in this insect that humidity had any effect on the respiratory pattern. The results are discussed in the context of the ongoing discussion in the literature of the origin, maintenance and adaptive significance of the DGC in insects.

Respiratory comfort and breathing pattern during volume proportional assist ventilation and pressure support ventilation: a study on volunteers with artificially reduced compliance.

PubMed

Mols, G; von Ungern-Sternberg, B; Rohr, E; Haberthür, C; Geiger, K; Guttmann, J

2000-06-01

To assess respiratory comfort and associated breathing pattern during volume assist (VA) as a component of proportional assist ventilation and during pressure support ventilation (PSV). Prospective, double-blind, interventional study. Laboratory. A total of 15 healthy volunteers (11 females, 4 males) aged 21-31 yrs. Decreased respiratory system compliance was simulated by banding of the thorax and abdomen. Volunteers breathed via a mouthpiece with VA and PSV each applied at two levels (VA, 8 cm H2O/L and 12 cm H2O/L; PSV, 10 cm H2O and 15 cm H2O) using a positive end-expiratory pressure of 5 cm H2O throughout. The study was subdivided into two parts. In Part 1, volunteers breathed three times with each of the four settings for 2 mins in random order. In Part 2, the first breath effects of multiple, randomly applied mode, and level shifts were studied. In Part 1, the volunteers were asked to estimate respiratory comfort in comparison with normal breathing using a visual analog scale. In Part 2, they were asked to estimate the change of respiratory comfort as increased, decreased, or unchanged immediately after a mode shift. Concomitantly, the respiratory pattern (change) was characterized with continuously measured tidal volume, respiratory rate, pressure, and gas flow. Respiratory comfort during VA was higher than during PSV. The higher support level was less important during VA but had a major negative influence on comfort during PSV. Both modes differed with respect to the associated breathing pattern. Variability of breathing was higher during VA than during PSV (Part 1). Changes in respiratory variables were associated with changes in respiratory comfort (Part 2). For volunteers breathing with artificially reduced respiratory system compliance, respiratory comfort is higher with VA than with PSV. This is probably caused by a better adaptation of the ventilatory support to the volunteer's need with VA.

Formation of a stable mimic of ambient particulate matter containing viable infectious respiratory syncytial virus and its dry-deposition directly onto cell cultures.

PubMed

Cruz-Sanchez, Teresita M; Haddrell, Allen E; Hackett, Tillie L; Singhera, Gurpreet K; Marchant, David; Lekivetz, Ryan; Meredith, Anna; Horne, Derrick; Knight, Darryl A; van Eeden, Stephen F; Bai, Tony R; Hegele, Richard G; Dorscheid, Delbert R; Agnes, George R

2013-01-15

Epidemiological associations of worse respiratory outcomes from combined exposure to ambient particulate matter (PM) and respiratory viral infection suggest possible interactions between PM and viruses. To characterize outcomes of such exposures, we developed an in vitro mimic of the in vivo event of exposure to PM contaminated with respiratory syncytial virus (RSV). Concentration of infectious RSV stocks and a particle levitation apparatus were the foundations of the methodology developed to generate specific numbers of PM mimics (PM(Mimics)) of known composition for dry, direct deposition onto airway epithelial cell cultures. Three types of PM(Mimics) were generated for this study: (i) carbon alone (P(C)), (ii) carbon and infectious RSV (P(C+RSV)), and (iii) aerosols consisting of RSV (A(RSV)). P(C+RSV) were stable in solution and harbored infectious RSV for up to 6 months. Unlike A(RSV) infection, P(C+RSV) infection was found to be dynamin dependent and to cause lysosomal rupture. Cells dosed with PM(Mimics) comprised of RSV (A(RSV)), carbon (P(C)), or RSV and carbon (P(C+RSV)) responded differentially as exemplified by the secretion patterns of IL-6 and IL-8. Upon infection, and prior to lung cell death due to viral infection, regression analysis of these two mediators in response to incubation with A(RSV), P(C), or P(C+RSV) yielded higher concentrations upon infection with the latter and at earlier time points than the other PM(Mimics). In conclusion, this experimental platform provides an approach to study the combined effects of PM-viral interactions and airway epithelial exposures in the pathogenesis of respiratory diseases involving inhalation of environmental agents.

A compartment model of alveolar-capillary oxygen diffusion with ventilation-perfusion gradient and dynamics of air transport through the respiratory tract.

PubMed

Jaworski, Jacek; Redlarski, Grzegorz

2014-08-01

This paper presents a model of alveolar-capillary oxygen diffusion with dynamics of air transport through the respiratory tract. For this purpose electrical model representing the respiratory tract mechanics and differential equations representing oxygen membrane diffusion are combined. Relevant thermodynamic relations describing the mass of oxygen transported into the human body are proposed as the connection between these models, as well as the influence of ventilation-perfusion mismatch on the oxygen diffusion. The model is verified based on simulation results of varying exercise intensities and statistical calculations of the results obtained during various clinical trials. The benefit of the approach proposed is its application in simulation-based research aimed to generate quantitative data of normal and pathological conditions. Based on the model presented, taking into account many essential physiological processes and air transport dynamics, comprehensive and combined studies of the respiratory efficiency can be performed. The impact of physical exercise, precise changes in respiratory tract mechanics and alterations in breathing pattern can be analyzed together with the impact of various changes in alveolar-capillary oxygen diffusion. This may be useful in simulation of effects of many severe medical conditions and increased activity level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Measurement of Cyclic Flows in Trachea Using PIV and Numerical simulation

NASA Astrophysics Data System (ADS)

Bělka, Miloslav; Elcner, Jakub; Jedelský, Jan; Boiron, Olivier; Knapp, Yannick; Bailly, Lucie

2015-05-01

Inhalation of pharmaceutical aerosols is a convenient way to treat lung or even systemic diseases. For effective treatment it is very important to understand air flow characteristics within respiratory airways and determine deposition hot spots. In this paper the air flow in trachea was investigated by numerical simulations. To validate these results we carried out particle image velocimetry experiments and compared resulting velocity fields. Simplified geometry of respiratory airways from oral cavity to 4th generation of branching was employed. Air flow characteristics were analysed during sinusoidal breathing pattern for light activity conditions (period 4 s and tidal volume 1 l). The observed flow fields indicated that the flow in trachea is turbulent during the sinusoidal flow except phases of flow turnarounds. The flow was skewed to front side of the trachea during inspiration and had twin-peak profile during expiration because of the mixing from daughter branches. The methods were compared and good agreement was found. This validation of CFD simulation can result into its further usage in respiratory airflow studies.

Respiratory muscle tension as symptom generator in individuals with high anxiety sensitivity.

PubMed

Ritz, Thomas; Meuret, Alicia E; Bhaskara, Lavanya; Petersen, Sibylle

2013-02-01

Anxiety and panic are associated with the experience of a range of bodily symptoms, in particular unpleasant breathing sensations (dyspnea). Respiratory theories of panic disorder have focused on disturbances in blood gas regulation, but respiratory muscle tension as a source of dyspnea has not been considered. We therefore examined the potential of intercostal muscle tension to elicit dyspnea in individuals with high anxiety sensitivity, a risk factor for developing panic disorder. Individuals high and low in anxiety sensitivity (total N=62) completed four tasks: electromyogram biofeedback for tensing intercostal muscle, electromyogram biofeedback for tensing leg muscles, paced breathing at three different speeds, and a fine motor task. Global dyspnea, individual respiratory sensations, nonrespiratory sensations, and discomfort were assessed after each task, whereas respiratory pattern (respiratory inductance plethysmography) and end-tidal carbon dioxide (capnography) were measured continuously. In individuals with high compared to low anxiety sensitivity, intercostal muscle tension elicited a particularly strong report of obstruction (M=5.1, SD=3.6 versus M=2.5, SD=3.0), air hunger (M=1.9, SD=2.1 versus M=0.4, SD=0.8), hyperventilation symptoms (M=0.6, SD=0.6 versus M=0.1, SD=0.1), and discomfort (M=5.1, SD=3.2 versus M=2.2, SD=2.1) (all p values<.05). This effect was not explained by site-unspecific muscle tension, voluntary manipulation of respiration, or sustained task-related attention. Nonrespiratory control sensations were not significantly affected by tasks (F<1), and respiratory variables did not reflect any specific responding of high-Anxiety Sensitivity Index participants to intercostal muscle tension. Respiratory muscle tension may contribute to the respiratory sensations experienced by panic-prone individuals. Theories and treatments for panic disorder should consider this potential source of symptoms.

Stress-induced thermotolerance of ventilatory motor pattern generation in the locust, Locusta migratoria.

PubMed

Newman, Amy E M; Foerster, Melody; Shoemaker, Kelly L; Robertson, R Meldrum

2003-11-01

Ventilation is a crucial motor activity that provides organisms with an adequate circulation of respiratory gases. For animals that exist in harsh environments, an important goal is to protect ventilation under extreme conditions. Heat shock, anoxia, and cold shock are environmental stresses that have previously been shown to trigger protective responses. We used the locust to examine stress-induced thermotolerance by monitoring the ability of the central nervous system to generate ventilatory motor patterns during a subsequent heat exposure. Preparations from pre-stressed animals had an increased incidence of motor pattern recovery following heat-induced failure, however, prior stress did not alter the characteristics of the ventilatory motor pattern. During constant heat exposure at sub-lethal temperatures, we observed a protective effect of heat shock pre-treatment. Serotonin application had similar effects on motor patterns when compared to prior heat shock. These studies are consistent with previous studies that indicate prior exposure to extreme temperatures and hypoxia can protect neural operation against high temperature stress. They further suggest that the protective mechanism is a time-dependent process best revealed during prolonged exposure to extreme temperatures and is mediated by a neuromodulator such as serotonin.

Xenograft model for therapeutic drug testing in recurrent respiratory papillomatosis.

PubMed

Ahn, Julie; Bishop, Justin A; Akpeng, Belinda; Pai, Sara I; Best, Simon R A

2015-02-01

Identifying effective treatment for papillomatosis is limited by a lack of animal models, and there is currently no preclinical model for testing potential therapeutic agents. We hypothesized that xenografting of papilloma may facilitate in vivo drug testing to identify novel treatment options. A biopsy of fresh tracheal papilloma was xenografted into a NOD-scid-IL2Rgamma(null) (NSG) mouse. The xenograft began growing after 5 weeks and was serially passaged over multiple generations. Each generation showed a consistent log-growth pattern, and in all xenografts, the presence of the human papillomavirus (HPV) genome was confirmed by polymerase chain reaction (PCR). Histopathologic analysis demonstrated that the squamous architecture of the original papilloma was maintained in each generation. In vivo drug testing with bevacizumab (5 mg/kg i.p. twice weekly for 3 weeks) showed a dramatic therapeutic response compared to saline control. We report here the first successful case of serial xenografting of a tracheal papilloma in vivo with a therapeutic response observed with drug testing. In severely immunocompromised mice, the HPV genome and squamous differentiation of the papilloma can be maintained for multiple generations. This is a feasible approach to identify therapeutic agents in the treatment of recurrent respiratory papillomatosis. © The Author(s) 2014.

Evaluation of a turbine flow meter (Ventilometer Mark 2) in the measurement of ventilation.

PubMed

Cooper, C B; Harris, N D; Howard, P

1990-01-01

We have evaluated a turbine flow meter (Ventilometer Mark 2, PK Morgan, Kent, UK) at low flow rates and levels of ventilation which are likely to be encountered during exercise in patients with chronic respiratory disease. Pulsatile flows were generated from a volume-cycled mechanical ventilator, the flow wave-form was modified by damping to simulate a human breathing pattern. Comparative measurements of ventilation were made whilst varying tidal volume (VT) from 0.22 to 1.131 and respiratory rate (fR) from 10 to 35 min-1. At lower levels of ventilation the instrument tended to underread especially with increasing fR. The calibration factor must be adjusted to match the level of ventilation if the measurement errors are to be within 5%.

Morphology of Dbx1 respiratory neurons in the preBötzinger complex and reticular formation of neonatal mice.

PubMed

Akins, Victoria T; Weragalaarachchi, Krishanthi; Picardo, Maria Cristina D; Revill, Ann L; Del Negro, Christopher A

2017-08-01

The relationship between neuron morphology and function is a perennial issue in neuroscience. Information about synaptic integration, network connectivity, and the specific roles of neuronal subpopulations can be obtained through morphological analysis of key neurons within a microcircuit. Here we present morphologies of two classes of brainstem respiratory neurons. First, interneurons derived from Dbx1-expressing precursors (Dbx1 neurons) in the preBötzinger complex (preBötC) of the ventral medulla that generate the rhythm for inspiratory breathing movements. Second, Dbx1 neurons of the intermediate reticular formation that influence the motor pattern of pharyngeal and lingual movements during the inspiratory phase of the breathing cycle. We describe the image acquisition and subsequent digitization of morphologies of respiratory Dbx1 neurons from the preBötC and the intermediate reticular formation that were first recorded in vitro. These data can be analyzed comparatively to examine how morphology influences the roles of Dbx1 preBötC and Dbx1 reticular interneurons in respiration and can also be utilized to create morphologically accurate compartmental models for simulation and modeling of respiratory circuits.

Deposition and clearance of inhaled particles.

PubMed Central

Stuart, B O

1984-01-01

Theoretical models of respiratory tract deposition of inhaled particles are compared to experimental studies of deposition patterns in humans and animals, as governed principally by particle size, density, respiratory rate and flow parameters. Various models of inhaled particle deposition make use of approximations of the respiratory tract to predict fractional deposition caused by fundamental physical processes of particle impaction, sedimentation, and diffusion. These models for both total deposition and regional (nasopharyngeal, tracheobronchial, and pulmonary) deposition are compared with early and recent experimental studies. Reasonable correlation has been obtained between theoretical and experimental studies, but the behavior in the respiratory tract of very fine (less than 0.1 micron) particles requires further investigation. Properties of particle shape, charge and hygroscopicity as well as the degree of respiratory tract pathology also influence deposition patterns; definitive experimental work is needed in these areas. The influence upon deposition patterns of dynamic alterations in inspiratory flow profiles caused by a variety of breathing patterns also requires further study, and the use of differing ventilation techniques with selected inhaled particle sizes holds promise in diagnosis of respiratory tract diseases. Mechanisms of conducting airway and alveolar clearance processes involving the pulmonary macrophage, mucociliary clearance, dissolution, transport to systemic circulation, and translocation via regional lymphatic vessels are discussed. PMID:6376108

Discharge Identity of Medullary Inspiratory Neurons is Altered during Repetitive Fictive Cough

PubMed Central

Segers, L. S.; Nuding, S. C.; Vovk, A.; Pitts, T.; Baekey, D. M.; O’Connor, R.; Morris, K. F.; Lindsey, B. G.; Shannon, R.; Bolser, Donald C.

2012-01-01

This study investigated the stability of the discharge identity of inspiratory decrementing (I-Dec) and augmenting (I-Aug) neurons in the caudal (cVRC) and rostral (rVRC) ventral respiratory column during repetitive fictive cough in the cat. Inspiratory neurons in the cVRC (n = 23) and rVRC (n = 17) were recorded with microelectrodes. Fictive cough was elicited by mechanical stimulation of the intrathoracic trachea. Approximately 43% (10 of 23) of I-Dec neurons shifted to an augmenting discharge pattern during the first cough cycle (C1). By the second cough cycle (C2), half of these returned to a decrementing pattern. Approximately 94% (16 of 17) of I-Aug neurons retained an augmenting pattern during C1 of a multi-cough response episode. Phrenic burst amplitude and inspiratory duration increased during C1, but decreased with each subsequent cough in a series of repetitive coughs. As a step in evaluating the model-driven hypothesis that VRC I-Dec neurons contribute to the augmentation of inspiratory drive during cough via inhibition of VRC tonic expiratory neurons that inhibit premotor inspiratory neurons, cross-correlation analysis was used to assess relationships of tonic expiratory cells with simultaneously recorded inspiratory neurons. Our results suggest that reconfiguration of inspiratory-related sub-networks of the respiratory pattern generator occurs on a cycle-by-cycle basis during repetitive coughing. PMID:22754536

SU-G-JeP4-02: An Investigation of Respiratory Surrogate Motion Data Requirements for Multiple-Step Ahead Prediction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zawisza, I; Ren, L; Yin, F

Purpose: Respiratory-gated radiotherapy and dynamic tracking employ real-time imaging and surrogate motion-monitoring methods with tumor motion prediction in advance of real-time. This study investigated respiratory motion data length on prediction accuracy of tumor motion. Methods: Predictions generated from the algorithm are validated against a one-dimensional surrogate signal of amplitude versus time. Prediction consists of three major components: extracting top-ranked subcomponents from training data matching the last respiratory cycle; calculating weighting factors from best-matched subcomponents; fusing data proceeding best-matched subcomponents with respective weighting factors to form predictions. Predictions for one respiratory cycle (∼3-6seconds) were assessed using 351 patient data from themore » respiratory management device. Performance was evaluated for correlation coefficient and root mean square error (RMSE) between prediction and final respiratory cycle. Results: Respiratory prediction results fell into two classes, where best predictions for 70 cycles or less performed using relative prediction and greater than 70 cycles are predicted similarly using relative and derivative relative. For 70 respiratory cycles or less, the average correlation between prediction and final respiratory cycle was 0.9999±0.0001, 0.9999±0.0001, 0.9988±0.0003, 0.9985±0.0023, and 0.9981±0.0023 with RMSE values of 0.0091±0.0030, 0.0091±0.0030, 0.0305±0.0051, 0.0299±0.0259, and 0.0299±0.0259 for equal, relative, pattern, derivative equal and derivative relative weighting methods, respectively. Respectively, the total best prediction for each method was 37, 65, 20, 22, and 22. For data with greater than 70 cycles average correlation was 0.9999±0.0001, 0.9999±0.0001, 0.9988±0.0004, 0.9988±0.0020, and 0.9988±0.0020 with RMSE values of 0.0081±0.0031, 0.0082±0.0033, 0.0306±0.0056, 0.0218±0.0222, and 0.0218±0.0222 for equal, relative, pattern, derivative equal and derivative relative weighting methods, respectively. Respectively, the total best prediction for each method was 24, 44, 42, 30, and 45. Conclusion: The prediction algorithms are effective in estimating surrogate motion in advance. These results indicate an advantage in using relative prediction for shorter data and either relative or derivative relative prediction for longer data.« less

Singing with reduced air sac volume causes uniform decrease in airflow and sound amplitude in the zebra finch.

PubMed

Plummer, Emily Megan; Goller, Franz

2008-01-01

Song of the zebra finch (Taeniopygia guttata) is a complex temporal sequence generated by a drastic change to the regular oscillations of the normal respiratory pattern. It is not known how respiratory functions, such as supply of air volume and gas exchange, are controlled during song. To understand the integration between respiration and song, we manipulated respiration during song by injecting inert dental medium into the air sacs. Increased respiratory rate after injections indicates that the reduction of air affected quiet respiration and that birds compensated for the reduced air volume. During song, air sac pressure, tracheal airflow and sound amplitude decreased substantially with each injection. This decrease was consistently present during each expiratory pulse of the song motif irrespective of the air volume used. Few changes to the temporal pattern of song were noted, such as the increased duration of a minibreath in one bird and the decrease in duration of a long syllable in another bird. Despite the drastic reduction in air sac pressure, airflow and sound amplitude, no increase in abdominal muscle activity was seen. This suggests that during song, birds do not compensate for the reduced physiological or acoustic parameters. Neither somatosensory nor auditory feedback mechanisms appear to effect a correction in expiratory effort to compensate for reduced air sac pressure and sound amplitude.

Poster - Thur Eve - 11: A realistic respiratory trace generator and its application to respiratory management techniques.

PubMed

Quirk, S; Becker, N; Smith, W L

2012-07-01

Respiratory motion complicates radiotherapy treatment of thoracic and abdominal tumours. Simplified respiratory motions such as sinusoidal and single patient traces are often used to determine the impact of motion on respiratory management techniques in radiotherapy. Such simplifications only accurately model a small portion of patients, as most patients exhibit variability and irregularity beyond these models. We have preformed a comprehensive analysis of respiratory motion and developed a software tool that allows for explicit inclusion of variability. We utilize our realistic respiratory generator to customize respiratory traces to test the robustness of the estimate of internal gross target volumes (IGTV) by 4DCT and CBCT. We confirmed that good agreement is found between 4DCT and CBCT for regular breathing motion. When amplitude variability was introduced the accuracy of the estimate slightly, but the absolute differences were still < 3 mm for both modalities. Poor agreement was shown with the addition of baseline drifts. Both modalities were found to underestimate the IGTV by as much as 30% for 4DCT and 25% for CBCT. Both large and small drifts deteriorated the estimate accuracy. The respiratory trace generator was advantageous for examining the difference between 4DCT and CBCT IGTV estimation under variable motions. It provided useful implementation abilities to test specific attributes of respiratory motion and detected issues that were not seen with the regular motion studies. This is just one example of how the respiratory trace generator can be utilized to test applications of respiratory management techniques. © 2012 American Association of Physicists in Medicine.

Early postnatal changes in respiratory activity in rat in vitro and modulatory effects of substance P.

PubMed

Shvarev, Y N; Lagercrantz, H

2006-10-01

Developmental changes in the respiratory activity and its modulation by substance P (SP) were studied in the neonatal rat brainstem-spinal cord preparation from the day of birth to day 3 (P0-P3). The respiratory network activity in the ventrolateral medulla was represented by two types of bursts: basic regular bursts with typical decrementing shape and biphasic bursts appearing after augmented biphasic discharges in inspiratory neurons. With advancing postnatal age the respiratory output was considerably modified; the basic rhythm became faster by 20%, whereas the biphasic burst rate, which was originally 15 times slower, declined further by 180% and the C4 burst duration significantly decreased by 20% due to reduced decay time without preceding changes in the central inspiratory drive. SP had an age-dependent excitatory effect on respiratory activity. In the basic rhythm, SP could induce transient rhythm cessations on P0-P2 but not on P3. For the biphasic burst frequency, the sensitivity to SP significantly decreased from P0 to P3, whereas the range of SP-induced changes increased. In both types of bursts, SP prolonged C4 burst duration due to increasing decay time. This effect was three times greater on P3 and did not depend on the central inspiratory drive. Our results suggest that the potency of SP to regulate the respiratory activity elevates during the early postnatal period. The developmental changes in the respiratory activity appear to represent the transient stage in the maturation of rhythm and pattern generation mechanisms facilitating adaptive behavior of a quickly growing organism.

Changes of Respiratory Mechanics in COPD Patients from Stable State to Acute Exacerbations with Respiratory Failure.

PubMed

Ceriana, Piero; Vitacca, Michele; Carlucci, Annalisa; Paneroni, Mara; Pisani, Lara; Nava, Stefano

2017-04-01

Symptoms, clinical course, functional and biological data during an exacerbation of chronic obstructive pulmonary disease (EXCOPD) have been investigated, but data on physiological changes of respiratory mechanics during a severe exacerbation with respiratory acidosis requiring noninvasive mechanical ventilation (NIMV) are scant. The aim of this study was to evaluate changes of respiratory mechanics in COPD patients comparing data observed during EXCOPD with those observed during stable state in the recovery phase. In 18 COPD patients having severe EXCOPD requiring NIMV for global respiratory failure, we measured respiratory mechanics during both EXCOPD (T0) and once the patients achieved a stable state (T1). The diaphragm and inspiratory muscles effort was significantly increased under relapse, as well as the pressure-time product of the diaphragm and the inspiratory muscle (PTPdi and PTPes). The resistive loads to breathe (i.e., PEEPi,dyn, compliance and inspiratory resistances) were also markedly increased, while the maximal pressures generated by the diaphragm and the inspiratory muscles, together with forced expired volumes were decreased. All these indices statistically improved but with a great intrasubject variability in stable condition. Moreover, tension-time index (TTdi) significantly improved from the EXCOPD state to the condition of clinical stability (0.156 ± 0.04 at T0 vs. 0.082 ± 0.02 at T1 p < 0.001). During an EXCOPD, the load/capacity of the respiratory pump is impaired, and although the patients exhibit a rapid shallow breathing pattern, this does not necessarily correlate with a TTdi ≥ 0.15. These changes are reverted once they recover from the EXCOPD, despite a large variability between patients.

Cardiac and respiratory patterns synchronize between persons during choir singing.

PubMed

Müller, Viktor; Lindenberger, Ulman

2011-01-01

Dyadic and collective activities requiring temporally coordinated action are likely to be associated with cardiac and respiratory patterns that synchronize within and between people. However, the extent and functional significance of cardiac and respiratory between-person couplings have not been investigated thus far. Here, we report interpersonal oscillatory couplings among eleven singers and one conductor engaged in choir singing. We find that: (a) phase synchronization both in respiration and heart rate variability increase significantly during singing relative to a rest condition; (b) phase synchronization is higher when singing in unison than when singing pieces with multiple voice parts; (c) directed coupling measures are consistent with the presence of causal effects of the conductor on the singers at high modulation frequencies; (d) the different voices of the choir are reflected in network analyses of cardiac and respiratory activity based on graph theory. Our results suggest that oscillatory coupling of cardiac and respiratory patterns provide a physiological basis for interpersonal action coordination.

Cardiac and Respiratory Patterns Synchronize between Persons during Choir Singing

PubMed Central

Müller, Viktor; Lindenberger, Ulman

2011-01-01

Dyadic and collective activities requiring temporally coordinated action are likely to be associated with cardiac and respiratory patterns that synchronize within and between people. However, the extent and functional significance of cardiac and respiratory between-person couplings have not been investigated thus far. Here, we report interpersonal oscillatory couplings among eleven singers and one conductor engaged in choir singing. We find that: (a) phase synchronization both in respiration and heart rate variability increase significantly during singing relative to a rest condition; (b) phase synchronization is higher when singing in unison than when singing pieces with multiple voice parts; (c) directed coupling measures are consistent with the presence of causal effects of the conductor on the singers at high modulation frequencies; (d) the different voices of the choir are reflected in network analyses of cardiac and respiratory activity based on graph theory. Our results suggest that oscillatory coupling of cardiac and respiratory patterns provide a physiological basis for interpersonal action coordination. PMID:21957466

Coupled in silico platform: Computational fluid dynamics (CFD) and physiologically-based pharmacokinetic (PBPK) modelling.

PubMed

Vulović, Aleksandra; Šušteršič, Tijana; Cvijić, Sandra; Ibrić, Svetlana; Filipović, Nenad

2018-02-15

One of the critical components of the respiratory drug delivery is the manner in which the inhaled aerosol is deposited in respiratory tract compartments. Depending on formulation properties, device characteristics and breathing pattern, only a certain fraction of the dose will reach the target site in the lungs, while the rest of the drug will deposit in the inhalation device or in the mouth-throat region. The aim of this study was to link the Computational fluid dynamics (CFD) with physiologically-based pharmacokinetic (PBPK) modelling in order to predict aerolisolization of different dry powder formulations, and estimate concomitant in vivo deposition and absorption of amiloride hydrochloride. Drug physicochemical properties were experimentally determined and used as inputs for the CFD simulations of particle flow in the generated 3D geometric model of Aerolizer® dry powder inhaler (DPI). CFD simulations were used to simulate air flow through Aerolizer® inhaler and Discrete Phase Method (DPM) was used to simulate aerosol particles deposition within the fluid domain. The simulated values for the percent emitted dose were comparable to the values obtained using Andersen cascade impactor (ACI). However, CFD predictions indicated that aerosolized DPI have smaller particle size and narrower size distribution than assumed based on ACI measurements. Comparison with the literature in vivo data revealed that the constructed drug-specific PBPK model was able to capture amiloride absorption pattern following oral and inhalation administration. The PBPK simulation results, based on the CFD generated particle distribution data as input, illustrated the influence of formulation properties on the expected drug plasma concentration profiles. The model also predicted the influence of potential changes in physiological parameters on the extent of inhaled amiloride absorption. Overall, this study demonstrated the potential of the combined CFD-PBPK approach to model inhaled drug bioperformance, and suggested that CFD generated results might serve as input for the prediction of drug deposition pattern in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

CO2-evoked release of PGE2 modulates sighs and inspiration as demonstrated in brainstem organotypic culture

PubMed Central

Forsberg, David; Horn, Zachi; Tserga, Evangelia; Smedler, Erik; Silberberg, Gilad; Shvarev, Yuri; Kaila, Kai; Uhlén, Per; Herlenius, Eric

2016-01-01

Inflammation-induced release of prostaglandin E2 (PGE2) changes breathing patterns and the response to CO2 levels. This may have fatal consequences in newborn babies and result in sudden infant death. To elucidate the underlying mechanisms, we present a novel breathing brainstem organotypic culture that generates rhythmic neural network and motor activity for 3 weeks. We show that increased CO2 elicits a gap junction-dependent release of PGE2. This alters neural network activity in the preBötzinger rhythm-generating complex and in the chemosensitive brainstem respiratory regions, thereby increasing sigh frequency and the depth of inspiration. We used mice lacking eicosanoid prostanoid 3 receptors (EP3R), breathing brainstem organotypic slices and optogenetic inhibition of EP3R+/+ cells to demonstrate that the EP3R is important for the ventilatory response to hypercapnia. Our study identifies a novel pathway linking the inflammatory and respiratory systems, with implications for inspiration and sighs throughout life, and the ability to autoresuscitate when breathing fails. DOI: http://dx.doi.org/10.7554/eLife.14170.001 PMID:27377173

An open-loop controlled active lung simulator for preterm infants.

PubMed

Cecchini, Stefano; Schena, Emiliano; Silvestri, Sergio

2011-01-01

We describe the underlying theory, design and experimental evaluation of an electromechanical analogue infant lung to simulate spontaneous breathing patterns of preterm infants. The aim of this work is to test the possibility to obtain breathing patterns of preterm infants by taking into consideration the air compressibility. Respiratory volume function represents the actuation pattern, and pulmonary pressure and flow-rate waveforms are mathematically obtained through the application of the perfect gas and adiabatic laws. The mathematical model reduces the simulation interval into a step shorter than 1 ms, allowing to consider an entire respiratory act as composed of a large number of almost instantaneous adiabatic transformations. The device consists of a spherical chamber where the air is compressed by four cylinder-pistons, moved by stepper motors, and flows through a fluid-dynamic resistance, which also works as flow-rate sensor. Specifically designed software generates the actuators motion, based on the desired ventilation parameters, without controlling the gas pneumatic parameters with a closed-loop. The system is able to simulate tidal volumes from 3 to 8 ml, breathing frequencies from 60 to 120 bpm and functional residual capacities from 25 to 80 ml. The simulated waveforms appear very close to the measured ones. Percentage differences on the tidal volume waveform vary from 7% for the tidal volume of 3 ml, down to 2.2-3.5% for tidal volumes in the range of 4-7 ml, and 1.3% for the tidal volume equal to 8 ml in the whole breathing frequency and functional residual capacity ranges. The open-loop electromechanical simulator shows that gas compressibility can be theoretically assessed in the typical pneumatic variable range of preterm infant respiratory mechanics. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Correlation of respiratory symptoms and spirometric lung patterns in a rural community setting, Sindh, Pakistan: a cross sectional survey

PubMed Central

2012-01-01

Background Symptom-based questionnaires can be a cost effective tool enabling identification and diagnosis of patients with respiratory illnesses in resource limited setting. This study aimed to determine the correlation of respiratory symptoms and spirometric lung patterns and validity of ATS respiratory questionnaire in a rural community setting. Methods This cross sectional survey was conducted between January – March 2009 on a sample of 200 adults selected from two villages of district Khairpur, Sindh, Pakistan. A modified version of the American thoracic society division of lung disease questionnaire was used to record the presence of respiratory symptoms. Predicted lung volumes i.e. forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and their ratio (FEV1/FVC) were recorded using portable spirometer. Results In the study sample there were 91 (45.5%) males and 109 (54.5%) females with overall mean age of 34 years (±11.69). Predominant respiratory symptom was phlegm (19%) followed by cough (17.5%), wheeze (14%) and dyspnea (10.5%). Prevalence of physician diagnosed and self-reported asthma was 5.5% and 9.5% respectively. Frequency of obstructive pattern on spirometry was 28.72% and that of restrictive pattern was 19.68%. After adjustment for age, gender, socioeconomic status, spoken dialect, education, smoking status, height, weight and arsenic in drinking water, FVC was significantly reduced for phlegm (OR 3.01; 95% CI: 1.14 – 7.94), wheeze (OR 7.22; 95% CI: 2.52 – 20.67) and shortness of breath (OR 4.91; 95% CI: 1.57 – 15.36); and FEV1 was significantly reduced for cough (OR 2.69; 95% CI: 1.12 – 6.43), phlegm (OR 3.01; 95% CI: 1.26 – 7.16) and wheeze (OR 10.77; 95% CI: 3.45 – 33.6). Presence of respiratory symptoms was significantly associated with restrictive and/or obstructive patterns after controlling for confounders. Similar findings were observed through linear regression where respiratory symptoms were found to be significantly associated with decrements in lung volumes. Specificity and positive predictive values were found to be higher for all the symptoms compared to sensitivity and negative predictive values. Conclusion Symptoms based respiratory questionnaires are a valuable tool for screening of respiratory symptoms in resource poor, rural community setting. PMID:23249311

Depletion of substance P and glutamate by capsaicin blocks respiratory rhythm in neonatal rat in vitro

PubMed Central

Morgado-Valle, Consuelo; Feldman, Jack L

2004-01-01

The specific role of the neuromodulator substance P (SP) and its target, the neurokinin 1 receptor (NK1R), in the generation and regulation of respiratory activity is not known. The preBötzinger complex (preBötC), an essential site for respiratory rhythm generation, contains glutamatergic NK1R-expressing neurones that are strongly modulated by exogenously applied SP or acute pharmacological blockade of NK1Rs. We investigated the effects of capsaicin, which depletes neuropeptides (including SP) and glutamate from presynaptic terminals, on respiratory motor output in medullary slice preparations of neonatal rat that generate respiratory-related activity. Bath application of capsaicin slowed respiratory motor output in a dose- and time-dependent manner. Respiratory rhythm could be restored by bath application of SP or glutamate transporter blockers. Capsaicin also evoked dose-dependent glutamate release and depleted SP in fibres within the preBötC. Our results suggest that depletion of SP (or other peptides) and/or glutamate by capsaicin causes a cessation of respiratory rhythm in neonatal rat slices. PMID:14724197

Depletion of substance P and glutamate by capsaicin blocks respiratory rhythm in neonatal rat in vitro.

PubMed

Morgado-Valle, Consuelo; Feldman, Jack L

2004-03-16

The specific role of the neuromodulator substance P (SP) and its target, the neurokinin 1 receptor (NK1R), in the generation and regulation of respiratory activity is not known. The preBötzinger complex (preBötC), an essential site for respiratory rhythm generation, contains glutamatergic NK1R-expressing neurones that are strongly modulated by exogenously applied SP or acute pharmacological blockade of NK1Rs. We investigated the effects of capsaicin, which depletes neuropeptides (including SP) and glutamate from presynaptic terminals, on respiratory motor output in medullary slice preparations of neonatal rat that generate respiratory-related activity. Bath application of capsaicin slowed respiratory motor output in a dose- and time-dependent manner. Respiratory rhythm could be restored by bath application of SP or glutamate transporter blockers. Capsaicin also evoked dose-dependent glutamate release and depleted SP in fibres within the preBötC. Our results suggest that depletion of SP (or other peptides) and/or glutamate by capsaicin causes a cessation of respiratory rhythm in neonatal rat slices.

Respiratory motor training and neuromuscular plasticity in patients with chronic obstructive pulmonary disease: A pilot study.

PubMed

Ovechkin, Alexander V; Sayenko, Dimitry G; Ovechkina, Elena N; Aslan, Sevda C; Pitts, Teresa; Folz, Rodney J

2016-07-15

The objective of this study was to examine the feasibility of a full-scale investigation of the neurophysiological mechanisms of COPD-induced respiratory neuromuscular control deficits. Characterization of respiratory single- and multi-muscle activation patterns using surface electromyography (sEMG) were assessed along with functional measures at baseline and following 21±2 (mean±SD) sessions of respiratory motor training (RMT) performed during a one-month period in four patients with GOLD stage II or III COPD. Pre-training, the individuals with COPD showed significantly increased (p<0.05) overall respiratory muscle activity and disorganized multi-muscle activation patterns in association with lowered spirometrical measures and decreased fast- and slow-twitch fiber activity as compared to healthy controls (N=4). Following RMT, functional and respiratory sEMG activation outcomes during quite breathing and forced expiratory efforts were improved suggesting that functional improvements, induced by task-specific RMT, are evidence respiratory neuromuscular networks re-organization. Published by Elsevier B.V.

Patterns of antimicrobial use for respiratory tract infections in older residents of long-term care facilities

USDA-ARS?s Scientific Manuscript database

OBJECTIVE: To describe patterns of antimicrobial use for respiratory tract infections (RTIs) among elderly residents of long-term care facilities (LTCFs). DESIGN: Data from a prospective, randomized, controlled study conducted from April 1998 through August 2001 to investigate the effect of vitamin ...

MODULAR APPLICATION OF COMPUTATIONAL MODELS OF INHALED REACTIVE GAS DOSIMETRY FOR RISK ASSESSMENT OF RESPIRATORY TRACT TOXICITY: CHLORINE

EPA Science Inventory

Inhaled reactive gases typically cause respiratory tract toxicity with a prominent proximal to distal lesion pattern. This pattern is largely driven by airflow and interspecies differences between rodents and humans result from factors such as airway architecture, ventilation ra...

Effect of Facemask Use on Respiratory Patterns of Women in Speech and Singing

ERIC Educational Resources Information Center

Collyer, Sally; Davis, Pamela J.

2006-01-01

Purpose: Research into respiratory behavior during singing and speech makes extensive use of standard respiratory and vented pneumotachograph facemasks. This study investigated whether the use of such facemasks would affect respiratory behavior in terms of lung volume (excursion, at initiation and at termination) or duration (of inspiration and of…

Respiratory mechanics and breathing pattern in the neonatal foal.

PubMed

Koterba, A M; Kosch, P C

1987-01-01

Breathing pattern, respiratory muscle activation pattern, lung volumes and volume-pressure characteristics of the respiratory system of normal, term, neonatal foals on Days 2 and 7 of age were determined to test the hypothesis that the foal actively maintains end-expiratory lung volume (EEV) greater than the relaxation volume of the respiratory system (Vrx) because of a highly compliant chest wall. Breathing pattern was measured in the awake, unsedated foal during quiet breathing in lateral and standing positions. The typical neonatal foal breathing pattern was characterized by a monophasic inspiratory and expiratory flow pattern. Both inspiration and expiration were active, with onset of Edi activity preceding onset of inspiratory flow, and phasic abdominal muscle activity detectable throughout most of expiration. No evidence was found to support the hypothesis that the normal, term neonatal foal actively maintains EEV greater than Vrx. In the neonatal foal, normalized lung volume and lung compliance values were similar to those reported for neonates of other species, while normalized chest wall compliance was considerably lower. We conclude that the chest wall of the term neonatal foal is sufficiently rigid to prevent a low Vrx. This characteristic probably prevents the foal from having to use a breathing strategy which maintains an EEV greater than Vrx.

Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

PubMed Central

Persson, Karin; Rekling, Jens C

2011-01-01

Abstract The brainstem contains rhythm and pattern forming circuits, which drive cranial and spinal motor pools to produce respiratory and other motor patterns. Here we used calcium imaging combined with nerve recordings in newborn mice to reveal spontaneous population activity in the ventral brainstem and in the facial nucleus. In Fluo-8 AM loaded brainstem–spinal cord preparations, respiratory activity on cervical nerves was synchronized with calcium signals at the ventrolateral brainstem surface. Individual ventrolateral neurons at the level of the parafacial respiratory group showed perfect or partial synchrony with respiratory nerve bursts. In brainstem–spinal cord preparations, cut at the level of the mid-facial nucleus, calcium signals were recorded in the dorsal, lateral and medial facial subnuclei during respiratory activity. Strong activity initiated in the dorsal subnucleus, followed by activity in lateral and medial subnuclei. Whole-cell recordings from facial motoneurons showed weak respiratory drives, and electrical field potential recordings confirmed respiratory drive to particularly the dorsal and lateral subnuclei. Putative facial premotoneurons showed respiratory-related calcium signals, and were predominantly located dorsomedial to the facial nucleus. A novel motor activity on facial, cervical and thoracic nerves was synchronized with calcium signals at the ventromedial brainstem extending from the level of the facial nucleus to the medulla–spinal cord border. Cervical dorsal root stimulation induced similar ventromedial activity. The medial facial subnucleus showed calcium signals synchronized with this novel motor activity on cervical nerves, and cervical dorsal root stimulation induced similar medial facial subnucleus activity. In conclusion, the dorsal and lateral facial subnuclei are strongly respiratory-modulated, and the brainstem contains a novel pattern forming circuit that drives the medial facial subnucleus and cervical motor pools. PMID:21486812

Respiration in neonate sea turtles.

PubMed

Price, Edwin R; Paladino, Frank V; Strohl, Kingman P; Santidrián T, Pilar; Klann, Kenneth; Spotila, James R

2007-03-01

The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings' response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species' resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults.

Optimized respiratory-resolved motion-compensated 3D Cartesian coronary MR angiography.

PubMed

Correia, Teresa; Ginami, Giulia; Cruz, Gastão; Neji, Radhouene; Rashid, Imran; Botnar, René M; Prieto, Claudia

2018-04-22

To develop a robust and efficient reconstruction framework that provides high-quality motion-compensated respiratory-resolved images from free-breathing 3D whole-heart Cartesian coronary magnetic resonance angiography (CMRA) acquisitions. Recently, XD-GRASP (eXtra-Dimensional Golden-angle RAdial Sparse Parallel MRI) was proposed to achieve 100% scan efficiency and provide respiratory-resolved 3D radial CMRA images by exploiting sparsity in the respiratory dimension. Here, a reconstruction framework for Cartesian CMRA imaging is proposed, which provides respiratory-resolved motion-compensated images by incorporating 2D beat-to-beat translational motion information to increase sparsity in the respiratory dimension. The motion information is extracted from interleaved image navigators and is also used to compensate for 2D translational motion within each respiratory phase. The proposed Optimized Respiratory-resolved Cartesian Coronary MR Angiography (XD-ORCCA) method was tested on 10 healthy subjects and 2 patients with cardiovascular disease, and compared against XD-GRASP. The proposed XD-ORCCA provides high-quality respiratory-resolved images, allowing clear visualization of the right and left coronary arteries, even for irregular breathing patterns. Compared with XD-GRASP, the proposed method improves the visibility and sharpness of both coronaries. Significant differences (p < .05) in visible vessel length and proximal vessel sharpness were found between the 2 methods. The XD-GRASP method provides good-quality images in the absence of intraphase motion. However, motion blurring is observed in XD-GRASP images for respiratory phases with larger motion amplitudes and subjects with irregular breathing patterns. A robust respiratory-resolved motion-compensated framework for Cartesian CMRA has been proposed and tested in healthy subjects and patients. The proposed XD-ORCCA provides high-quality images for all respiratory phases, independently of the regularity of the breathing pattern. © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Measurement of various respiratory dynamics parameters following acute inhalational exposure to soman vapor in conscious rats.

PubMed

Perkins, Michael W; Wong, Benjamin; Rodriguez, Ashley; Devorak, Jennifer; Sciuto, Alfred M

2015-01-01

Respiratory dynamics were investigated in head-out plethysmography chambers following inhalational exposure to soman in untreated, non-anesthetized rats. A multipass saturator cell was used to generate 520, 560 and 600 mg × min/m(3) of soman vapor in a customized inhalational exposure system. Various respiratory dynamic parameters were collected from male Sprague-Dawley rats (300--350 g) during (20 min) and 24 h (10 min) after inhalational exposure. Signs of CWNA-induced cholinergic crisis were observed in all soman-exposed animals. Percentage body weight loss and lung edema were observed in all soman-exposed animals, with significant increases in both at 24 h following exposure to 600 mg × min/m(3). Exposure to soman resulted in increases in respiratory frequency (RF) in animals exposed to 560 and 600 mg × min/m(3) with significant increases following exposure to 560 mg × min/m(3) at 24 h. No significant alterations in inspiratory time (IT) or expiratory time (ET) were observed in soman-exposed animals 24 h post-exposure. Prominent increases in tidal volume (TV) and minute volume (MV) were observed at 24 h post-exposure in animals exposed to 600 mg × min/m(3). Peak inspiratory (PIF) and expiratory flow (PEF) followed similar patterns and increased 24 h post-exposure to 600 mg × min/m(3) of soman. Results demonstrate that inhalational exposure to 600 mg × min/m(3) soman produces notable alterations in various respiratory dynamic parameters at 24 h. The following multitude of physiological changes in respiratory dynamics highlights the need to develop countermeasures that protect against respiratory toxicity and lung injury.

Social contact patterns relevant to the spread of respiratory infectious diseases in Hong Kong.

PubMed

Leung, Kathy; Jit, Mark; Lau, Eric H Y; Wu, Joseph T

2017-08-11

The spread of many respiratory infections is determined by contact patterns between infectious and susceptible individuals in the population. There are no published data for quantifying social contact patterns relevant to the spread of respiratory infectious diseases in Hong Kong which is a hotspot for emerging infectious diseases due to its high population density and connectivity in the air transportation network. We adopted a commonly used diary-based design to conduct a social contact survey in Hong Kong in 2015/16 using both paper and online questionnaires. Participants using paper questionnaires reported more contacts and longer contact duration than those using online questionnaires. Participants reported 13 person-hours of contact and 8 contacts per day on average, which decreased over age but increased with household size, years of education and income level. Prolonged and frequent contacts, and contacts at home, school and work were more likely to involve physical contacts. Strong age-assortativity was observed in all age groups. We evaluated the characteristics of social contact patterns relevant to the spread of respiratory infectious diseases in Hong Kong. Our findings could help to improve the design of future social contact surveys, parameterize transmission models of respiratory infectious diseases, and inform intervention strategies based on model outputs.

Transmission characteristics of MERS and SARS in the healthcare setting: a comparative study.

PubMed

Chowell, Gerardo; Abdirizak, Fatima; Lee, Sunmi; Lee, Jonggul; Jung, Eunok; Nishiura, Hiroshi; Viboud, Cécile

2015-09-03

The Middle East respiratory syndrome (MERS) coronavirus has caused recurrent outbreaks in the Arabian Peninsula since 2012. Although MERS has low overall human-to-human transmission potential, there is occasional amplification in the healthcare setting, a pattern reminiscent of the dynamics of the severe acute respiratory syndrome (SARS) outbreaks in 2003. Here we provide a head-to-head comparison of exposure patterns and transmission dynamics of large hospital clusters of MERS and SARS, including the most recent South Korean outbreak of MERS in 2015. To assess the unexpected nature of the recent South Korean nosocomial outbreak of MERS and estimate the probability of future large hospital clusters, we compared exposure and transmission patterns for previously reported hospital clusters of MERS and SARS, based on individual-level data and transmission tree information. We carried out simulations of nosocomial outbreaks of MERS and SARS using branching process models rooted in transmission tree data, and inferred the probability and characteristics of large outbreaks. A significant fraction of MERS cases were linked to the healthcare setting, ranging from 43.5 % for the nosocomial outbreak in Jeddah, Saudi Arabia, in 2014 to 100 % for both the outbreak in Al-Hasa, Saudi Arabia, in 2013 and the outbreak in South Korea in 2015. Both MERS and SARS nosocomial outbreaks are characterized by early nosocomial super-spreading events, with the reproduction number dropping below 1 within three to five disease generations. There was a systematic difference in the exposure patterns of MERS and SARS: a majority of MERS cases occurred among patients who sought care in the same facilities as the index case, whereas there was a greater concentration of SARS cases among healthcare workers throughout the outbreak. Exposure patterns differed slightly by disease generation, however, especially for SARS. Moreover, the distributions of secondary cases per single primary case varied highly across individual hospital outbreaks (Kruskal-Wallis test; P < 0.0001), with significantly higher transmission heterogeneity in the distribution of secondary cases for MERS than SARS. Simulations indicate a 2-fold higher probability of occurrence of large outbreaks (>100 cases) for SARS than MERS (2 % versus 1 %); however, owing to higher transmission heterogeneity, the largest outbreaks of MERS are characterized by sharper incidence peaks. The probability of occurrence of MERS outbreaks larger than the South Korean cluster (n = 186) is of the order of 1 %. Our study suggests that the South Korean outbreak followed a similar progression to previously described hospital clusters involving coronaviruses, with early super-spreading events generating a disproportionately large number of secondary infections, and the transmission potential diminishing greatly in subsequent generations. Differences in relative exposure patterns and transmission heterogeneity of MERS and SARS could point to changes in hospital practices since 2003 or differences in transmission mechanisms of these coronaviruses.

Role of dorsolateral periaqueductal grey in the coordinated regulation of cardiovascular and respiratory function.

PubMed

Dampney, Roger A L; Furlong, Teri M; Horiuchi, Jouji; Iigaya, Kamon

2013-04-01

The midbrain periaqueductal grey (PAG) contains four longitudinal columns, referred to as the dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG) subdivisions, which collectively have a pivotal role in integrating behavioural and physiological responses to external stressors as well as other functions. This review is focussed on the dlPAG, which is believed to be an important component of the central mechanisms that generate the defensive response to acute psychological stressors, such as the presence of a predator or other immediate threat. The anatomical connections of the dlPAG are highly specific and distinctly different from those of the other PAG subregions. The chemical properties of the dlPAG are also distinctly different from the other PAG subregions (e.g. there is a very high density of neurons that synthesize nitric oxide in the dlPAG but very few such neurons in the other PAG subregions). Recent functional studies have demonstrated that neurons in the dlPAG exert a powerful control over both sympathetic and respiratory activity, and that the pattern of the evoked respiratory changes is also distinctly different from those evoked from other PAG subregions. These studies also showed that the sympathetic and respiratory changes evoked from the dlPAG are highly correlated, suggesting the possibility that a common population of "command neurons" within this region may generate the sympathetic and respiratory changes that accompany defensive behavioural responses to acute psychological stressors. Finally, although the anatomical connections and functional properties of the dlPAG are distinctly different from the other PAG subregions, they have many similarities with adjacent parts of the superior colliculus, suggesting that the dlPAG and deep layers of the superior colliculus may be part of a common defence system in the midbrain. Copyright © 2013 Elsevier B.V. All rights reserved.

Phrenic nerve deficits and neurological immunopathology associated with acute West Nile virus infection in mice and hamsters.

PubMed

Zukor, Katherine; Wang, Hong; Hurst, Brett L; Siddharthan, Venkatraman; Van Wettere, Arnaud; Pilowsky, Paul M; Morrey, John D

2017-04-01

Neurological respiratory deficits are serious outcomes of West Nile virus (WNV) disease. WNV patients requiring intubation have a poor prognosis. We previously reported that WNV-infected rodents also appear to have respiratory deficits when assessed by whole-body plethysmography and diaphragmatic electromyography. The purpose of this study was to determine if the nature of the respiratory deficits in WNV-infected rodents is neurological and if deficits are due to a disorder of brainstem respiratory centers, cervical spinal cord (CSC) phrenic motor neuron (PMN) circuitry, or both. We recorded phrenic nerve (PN) activity and found that in WNV-infected mice, PN amplitude is reduced, corroborating a neurological basis for respiratory deficits. These results were associated with a reduction in CSC motor neuron number. We found no dramatic deficits, however, in brainstem-mediated breathing rhythm generation or responses to hypercapnia. PN frequency and pattern parameters were normal, and all PN parameters changed appropriately upon a CO 2 challenge. Histological analysis revealed generalized microglia activation, astrocyte reactivity, T cell and neutrophil infiltration, and mild histopathologic lesions in both the brainstem and CSC, but none of these were tightly correlated with PN function. Similar results in PN activity, brainstem function, motor neuron number, and histopathology were seen in WNV-infected hamsters, except that histopathologic lesions were more severe. Taken together, the results suggest that respiratory deficits in acute WNV infection are primarily due to a lower motor neuron disorder affecting PMNs and the PN rather than a brainstem disorder. Future efforts should focus on markers of neuronal dysfunction, axonal degeneration, and myelination.

Respiration-related discharge of hyoglossus muscle motor units in the rat.

PubMed

Powell, Gregory L; Rice, Amber; Bennett-Cross, Seres J; Fregosi, Ralph F

2014-01-01

Although respiratory muscle motor units have been studied during natural breathing, simultaneous measures of muscle force have never been obtained. Tongue retractor muscles, such as the hyoglossus (HG), play an important role in swallowing, licking, chewing, breathing, and, in humans, speech. The HG is phasically recruited during the inspiratory phase of the respiratory cycle. Moreover, in urethane anesthetized rats the drive to the HG waxes and wanes spontaneously, providing a unique opportunity to study motor unit firing patterns as the muscle is driven naturally by the central pattern generator for breathing. We recorded tongue retraction force, the whole HG muscle EMG and the activity of 38 HG motor units in spontaneously breathing anesthetized rats under low-force and high-force conditions. Activity in all cases was confined to the inspiratory phase of the respiratory cycle. Changes in the EMG were correlated significantly with corresponding changes in force, with the change in EMG able to predict 53-68% of the force variation. Mean and peak motor unit firing rates were greater under high-force conditions, although the magnitude of discharge rate modulation varied widely across the population. Changes in mean and peak firing rates were significantly correlated with the corresponding changes in force, but the correlations were weak (r(2) = 0.27 and 0.25, respectively). These data indicate that, during spontaneous breathing, recruitment of HG motor units plays a critical role in the control of muscle force, with firing rate modulation playing an important but lesser role.

Respiratory Patterns and Strategies during Feeding in Preterm Infants

ERIC Educational Resources Information Center

Vice, Frank L.; Gewolb, Ira H.

2008-01-01

Because patterns of integration of respiration into rhythmic suck-swallow efforts are highly variable, we examined the vagaries of respiratory efforts as they evolve from the first tentative attempts at integration through more complex rhythmic interactions, with a focus on several strategies in which breathing and suck-swallow are coordinated.…

Pontine Mechanisms of Respiratory Control

PubMed Central

Dutschmann, Mathias; Dick, Thomas E.

2015-01-01

Pontine respiratory nuclei provide synaptic input to medullary rhythmogenic circuits to shape and adapt the breathing pattern. An understanding of this statement depends on appreciating breathing as a behavior, rather than a stereotypic rhythm. In this review, we focus on the pontine-mediated inspiratory off-switch (IOS) associated with postinspiratory glottal constriction. Further, IOS is examined in the context of pontine regulation of glottal resistance in response to multimodal sensory inputs and higher commands, which in turn rules timing, duration, and patterning of respiratory airflow. In addition, network plasticity in respiratory control emerges during the development of the pons. Synaptic plasticity is required for dynamic and efficient modulation of the expiratory breathing pattern to cope with rapid changes from eupneic to adaptive breathing linked to exploratory (foraging and sniffing) and expulsive (vocalizing, coughing, sneezing, and retching) behaviors, as well as conveyance of basic emotions. The speed and complexity of changes in the breathing pattern of behaving animals implies that “learning to breathe” is necessary to adjust to changing internal and external states to maintain homeostasis and survival. PMID:23720253

Automatic classification of canine PRG neuronal discharge patterns using K-means clustering.

PubMed

Zuperku, Edward J; Prkic, Ivana; Stucke, Astrid G; Miller, Justin R; Hopp, Francis A; Stuth, Eckehard A

2015-02-01

Respiratory-related neurons in the parabrachial-Kölliker-Fuse (PB-KF) region of the pons play a key role in the control of breathing. The neuronal activities of these pontine respiratory group (PRG) neurons exhibit a variety of inspiratory (I), expiratory (E), phase spanning and non-respiratory related (NRM) discharge patterns. Due to the variety of patterns, it can be difficult to classify them into distinct subgroups according to their discharge contours. This report presents a method that automatically classifies neurons according to their discharge patterns and derives an average subgroup contour of each class. It is based on the K-means clustering technique and it is implemented via SigmaPlot User-Defined transform scripts. The discharge patterns of 135 canine PRG neurons were classified into seven distinct subgroups. Additional methods for choosing the optimal number of clusters are described. Analysis of the results suggests that the K-means clustering method offers a robust objective means of both automatically categorizing neuron patterns and establishing the underlying archetypical contours of subtypes based on the discharge patterns of group of neurons. Published by Elsevier B.V.

A Nano-Thin Film-Based Prototype QCM Sensor Array for Monitoring Human Breath and Respiratory Patterns.

PubMed

Selyanchyn, Roman; Wakamatsu, Shunichi; Hayashi, Kenshi; Lee, Seung-Woo

2015-07-31

Quartz crystal microbalance (QCM) sensor array was developed for multi-purpose human respiration assessment. The sensor system was designed to provide feedback for human respiration. Thorough optimization of measurement conditions: air flow, temperature in the QCM chamber, frequency measurement rate, and electrode position regarding to the gas flow-was performed. As shown, acquisition of respiratory parameters (rate and respiratory pattern) could be achieved even with a single electrode used in the system. The prototype system contains eight available QCM channels that can be potentially used for selective responses to certain breath chemicals. At present, the prototype machine is ready for the assessment of respiratory functions in larger populations in order to gain statistical validation. To the best of our knowledge, the developed prototype is the only respiratory assessment system based on surface modified QCM sensors.

Respiratory rate detection using a wearable electromagnetic generator.

PubMed

Padasdao, Bryson; Boric-Lubecke, Olga

2011-01-01

Wearable health and fitness monitoring systems are a promising new way of collecting physiological data without inconveniencing patients. Human energy harvesting may be used to power wearable sensors. In this paper, we explore this zero-net energy biosensor concept through sensing and harvesting of respiratory effort. An off the shelf servo motor operation in reverse was used to successfully obtain respiratory rate, while also demonstrating significant harvested power. These are the first reported respiratory rate sensing results using electromagnetic generators.

TH-E-17A-01: Internal Respiratory Surrogate for 4D CT Using Fourier Transform and Anatomical Features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hui, C; Suh, Y; Robertson, D

Purpose: To develop a novel algorithm to generate internal respiratory signals for sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm extracted multiple time resolved features as potential respiratory signals. These features were taken from the 4D CT images and its Fourier transformed space. Several low-frequency locations in the Fourier space and selected anatomical features from the images were used as potential respiratory signals. A clustering algorithm was then used to search for the group of appropriate potential respiratory signals. The chosen signals were then normalized and averaged to form the final internal respiratory signal. Performance ofmore » the algorithm was tested in 50 4D CT data sets and results were compared with external signals from the real-time position management (RPM) system. Results: In almost all cases, the proposed algorithm generated internal respiratory signals that visibly matched the external respiratory signals from the RPM system. On average, the end inspiration times calculated by the proposed algorithm were within 0.1 s of those given by the RPM system. Less than 3% of the calculated end inspiration times were more than one time frame away from those given by the RPM system. In 3 out of the 50 cases, the proposed algorithm generated internal respiratory signals that were significantly smoother than the RPM signals. In these cases, images sorted using the internal respiratory signals showed fewer artifacts in locations corresponding to the discrepancy in the internal and external respiratory signals. Conclusion: We developed a robust algorithm that generates internal respiratory signals from 4D CT images. In some cases, it even showed the potential to outperform the RPM system. The proposed algorithm is completely automatic and generally takes less than 2 min to process. It can be easily implemented into the clinic and can potentially replace the use of external surrogates.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Heng, E-mail: hengli@mdanderson.org; Zhu, X. Ronald; Zhang, Xiaodong

Purpose: To develop and validate a novel delivery strategy for reducing the respiratory motion–induced dose uncertainty of spot-scanning proton therapy. Methods and Materials: The spot delivery sequence was optimized to reduce dose uncertainty. The effectiveness of the delivery sequence optimization was evaluated using measurements and patient simulation. One hundred ninety-one 2-dimensional measurements using different delivery sequences of a single-layer uniform pattern were obtained with a detector array on a 1-dimensional moving platform. Intensity modulated proton therapy plans were generated for 10 lung cancer patients, and dose uncertainties for different delivery sequences were evaluated by simulation. Results: Without delivery sequence optimization,more » the maximum absolute dose error can be up to 97.2% in a single measurement, whereas the optimized delivery sequence results in a maximum absolute dose error of ≤11.8%. In patient simulation, the optimized delivery sequence reduces the mean of fractional maximum absolute dose error compared with the regular delivery sequence by 3.3% to 10.6% (32.5-68.0% relative reduction) for different patients. Conclusions: Optimizing the delivery sequence can reduce dose uncertainty due to respiratory motion in spot-scanning proton therapy, assuming the 4-dimensional CT is a true representation of the patients' breathing patterns.« less

Testing the hypothesis of neurodegeneracy in respiratory network function with a priori transected arterially perfused brain stem preparation of rat

PubMed Central

Jones, Sarah E.

2016-01-01

Degeneracy of respiratory network function would imply that anatomically discrete aspects of the brain stem are capable of producing respiratory rhythm. To test this theory we a priori transected brain stem preparations before reperfusion and reoxygenation at 4 rostrocaudal levels: 1.5 mm caudal to obex (n = 5), at obex (n = 5), and 1.5 (n = 7) and 3 mm (n = 6) rostral to obex. The respiratory activity of these preparations was assessed via recordings of phrenic and vagal nerves and lumbar spinal expiratory motor output. Preparations with a priori transection at level of the caudal brain stem did not produce stable rhythmic respiratory bursting, even when the arterial chemoreceptors were stimulated with sodium cyanide (NaCN). Reperfusion of brain stems that preserved the pre-Bötzinger complex (pre-BötC) showed spontaneous and sustained rhythmic respiratory bursting at low phrenic nerve activity (PNA) amplitude that occurred simultaneously in all respiratory motor outputs. We refer to this rhythm as the pre-BötC burstlet-type rhythm. Conserving circuitry up to the pontomedullary junction consistently produced robust high-amplitude PNA at lower burst rates, whereas sequential motor patterning across the respiratory motor outputs remained absent. Some of the rostrally transected preparations expressed both burstlet-type and regular PNA amplitude rhythms. Further analysis showed that the burstlet-type rhythm and high-amplitude PNA had 1:2 quantal relation, with burstlets appearing to trigger high-amplitude bursts. We conclude that no degenerate rhythmogenic circuits are located in the caudal medulla oblongata and confirm the pre-BötC as the primary rhythmogenic kernel. The absence of sequential motor patterning in a priori transected preparations suggests that pontine circuits govern respiratory pattern formation. PMID:26888109

Testing the hypothesis of neurodegeneracy in respiratory network function with a priori transected arterially perfused brain stem preparation of rat.

PubMed

Jones, Sarah E; Dutschmann, Mathias

2016-05-01

Degeneracy of respiratory network function would imply that anatomically discrete aspects of the brain stem are capable of producing respiratory rhythm. To test this theory we a priori transected brain stem preparations before reperfusion and reoxygenation at 4 rostrocaudal levels: 1.5 mm caudal to obex (n = 5), at obex (n = 5), and 1.5 (n = 7) and 3 mm (n = 6) rostral to obex. The respiratory activity of these preparations was assessed via recordings of phrenic and vagal nerves and lumbar spinal expiratory motor output. Preparations with a priori transection at level of the caudal brain stem did not produce stable rhythmic respiratory bursting, even when the arterial chemoreceptors were stimulated with sodium cyanide (NaCN). Reperfusion of brain stems that preserved the pre-Bötzinger complex (pre-BötC) showed spontaneous and sustained rhythmic respiratory bursting at low phrenic nerve activity (PNA) amplitude that occurred simultaneously in all respiratory motor outputs. We refer to this rhythm as the pre-BötC burstlet-type rhythm. Conserving circuitry up to the pontomedullary junction consistently produced robust high-amplitude PNA at lower burst rates, whereas sequential motor patterning across the respiratory motor outputs remained absent. Some of the rostrally transected preparations expressed both burstlet-type and regular PNA amplitude rhythms. Further analysis showed that the burstlet-type rhythm and high-amplitude PNA had 1:2 quantal relation, with burstlets appearing to trigger high-amplitude bursts. We conclude that no degenerate rhythmogenic circuits are located in the caudal medulla oblongata and confirm the pre-BötC as the primary rhythmogenic kernel. The absence of sequential motor patterning in a priori transected preparations suggests that pontine circuits govern respiratory pattern formation. Copyright © 2016 the American Physiological Society.

Interaction between telencephalic signals and respiratory dynamics in songbirds

PubMed Central

Méndez, Jorge M.; Mindlin, Gabriel B.

2012-01-01

The mechanisms by which telencephalic areas affect motor activities are largely unknown. They could either take over motor control from downstream motor circuits or interact with the intrinsic dynamics of these circuits. Both models have been proposed for telencephalic control of respiration during learned vocal behavior in birds. The interactive model postulates that simple signals from the telencephalic song control areas are sufficient to drive the nonlinear respiratory network into producing complex temporal sequences. We tested this basic assumption by electrically stimulating telencephalic song control areas and analyzing the resulting respiratory patterns in zebra finches and in canaries. We found strong evidence for interaction between the rhythm of stimulation and the intrinsic respiratory rhythm, including naturally emerging subharmonic behavior and integration of lateralized telencephalic input. The evidence for clear interaction in our experimental paradigm suggests that telencephalic vocal control also uses a similar mechanism. Furthermore, species differences in the response of the respiratory system to stimulation show parallels to differences in the respiratory patterns of song, suggesting that the interactive production of respiratory rhythms is manifested in species-specific specialization of the involved circuitry. PMID:22402649

A Nano-Thin Film-Based Prototype QCM Sensor Array for Monitoring Human Breath and Respiratory Patterns

PubMed Central

Selyanchyn, Roman; Wakamatsu, Shunichi; Hayashi, Kenshi; Lee, Seung-Woo

2015-01-01

Quartz crystal microbalance (QCM) sensor array was developed for multi-purpose human respiration assessment. The sensor system was designed to provide feedback for human respiration. Thorough optimization of measurement conditions: air flow, temperature in the QCM chamber, frequency measurement rate, and electrode position regarding to the gas flow—was performed. As shown, acquisition of respiratory parameters (rate and respiratory pattern) could be achieved even with a single electrode used in the system. The prototype system contains eight available QCM channels that can be potentially used for selective responses to certain breath chemicals. At present, the prototype machine is ready for the assessment of respiratory functions in larger populations in order to gain statistical validation. To the best of our knowledge, the developed prototype is the only respiratory assessment system based on surface modified QCM sensors. PMID:26263994

The effects of breathing exercise types on respiratory muscle activity and body function in patients with mild chronic obstructive pulmonary disease.

PubMed

Kang, Jeong-Il; Jeong, Dae-Keun; Choi, Hyun

2016-01-01

[Purpose] Fragmentary studies on characteristics of respiratory muscles are being done to increase respiratory capacity by classifying exercises into voluntary respiratory exercise which relieves symptoms and prevents COPD and exercise using breathing exercise equipment. But this study found changes on respiratory pattern through changes on the activity pattern of agonist and synergist respiratory muscles and studied what effect they can have on body function improvement. [Subjects and Methods] Fifteen subjects in experimental group I that respiratory exercise of diaphragm and 15 subjects in experimental group II that feedback respiratory exercise were randomly selected among COPD patients to find the effective intervention method for COPD patients. And intervention program was conducted for 5 weeks, three times a week, once a day and 30 minutes a session. They were measured with BODE index using respiratory muscle activity, pulmonary function, the six-minute walking test, dyspnea criteria and BMI Then the results obtained were compared and analyzed. [Results] There was a significant difference in sternocleidomastoid muscle and scalene muscle and in 6-minute walk and BODE index for body function. Thus the group performing feedback respiratory had more effective results for mild COPD patients. [Conclusion] Therefore, the improvement was significant regarding the activity of respiratory muscles synergists when breathing before doing breathing exercise. Although, it is valuable to reduce too much mobilization of respiratory muscles synergists through the proper intervention it is necessary to study body function regarding improvement of respiratory function for patients with COPD.

Polyvinylidene fluoride film based nasal sensor to monitor human respiration pattern: an initial clinical study.

PubMed

Roopa Manjunatha, G; Rajanna, K; Mahapatra, D Roy; Nayak, M M; Krishnaswamy, Uma Maheswari; Srinivasa, R

2013-12-01

Design and development of a piezoelectric polyvinylidene fluoride (PVDF) thin film based nasal sensor to monitor human respiration pattern (RP) from each nostril simultaneously is presented in this paper. Thin film based PVDF nasal sensor is designed in a cantilever beam configuration. Two cantilevers are mounted on a spectacle frame in such a way that the air flow from each nostril impinges on this sensor causing bending of the cantilever beams. Voltage signal produced due to air flow induced dynamic piezoelectric effect produce a respective RP. A group of 23 healthy awake human subjects are studied. The RP in terms of respiratory rate (RR) and Respiratory air-flow changes/alterations obtained from the developed PVDF nasal sensor are compared with RP obtained from respiratory inductance plethysmograph (RIP) device. The mean RR of the developed nasal sensor (19.65 ± 4.1) and the RIP (19.57 ± 4.1) are found to be almost same (difference not significant, p > 0.05) with the correlation coefficient 0.96, p < 0.0001. It was observed that any change/alterations in the pattern of RIP is followed by same amount of change/alterations in the pattern of PVDF nasal sensor with k = 0.815 indicating strong agreement between the PVDF nasal sensor and RIP respiratory air-flow pattern. The developed sensor is simple in design, non-invasive, patient friendly and hence shows promising routine clinical usage. The preliminary result shows that this new method can have various applications in respiratory monitoring and diagnosis.

Learning to breathe and sing: development of respiratory-vocal coordination in young songbirds

PubMed Central

Veit, Lena; Aronov, Dmitriy

2011-01-01

How do animals with learned vocalizations coordinate vocal production with respiration? Songbirds such as the zebra finch learn their songs, beginning with highly variable babbling vocalizations known as subsong. After several weeks of practice, zebra finches are able to produce a precisely timed pattern of syllables and silences, precisely coordinated with expiratory and inspiratory pulses (Franz M, Goller F. J Neurobiol 51: 129–141, 2002). While respiration in adult song is well described, relatively little is known about respiratory patterns in subsong or about the processes by which respiratory and vocal patterns become coordinated. To address these questions, we recorded thoracic air sac pressure in juvenile zebra finches prior to the appearance of any consistent temporal or acoustic structure in their songs. We found that subsong contains brief inspiratory pulses (50 ms) alternating with longer pulses of sustained expiratory pressure (50–500 ms). In striking contrast to adult song, expiratory pulses often contained multiple (0–8) variably timed syllables separated by expiratory gaps and were only partially vocalized. During development, expiratory pulses became shorter and more stereotyped in duration with shorter and fewer nonvocalized parts. These developmental changes eventually resulted in the production of a single syllable per expiratory pulse and a single inspiratory pulse filling each gap, forming a coordinated sequence similar to that of adult song. To examine the role of forebrain song-control nuclei in the development of respiratory patterns, we performed pressure recordings before and after lesions of nucleus HVC (proper name) and found that this manipulation reverses the developmental trends in measures of the respiratory pattern. PMID:21697438

Learning to breathe and sing: development of respiratory-vocal coordination in young songbirds.

PubMed

Veit, Lena; Aronov, Dmitriy; Fee, Michale S

2011-10-01

How do animals with learned vocalizations coordinate vocal production with respiration? Songbirds such as the zebra finch learn their songs, beginning with highly variable babbling vocalizations known as subsong. After several weeks of practice, zebra finches are able to produce a precisely timed pattern of syllables and silences, precisely coordinated with expiratory and inspiratory pulses (Franz M, Goller F. J Neurobiol 51: 129-141, 2002). While respiration in adult song is well described, relatively little is known about respiratory patterns in subsong or about the processes by which respiratory and vocal patterns become coordinated. To address these questions, we recorded thoracic air sac pressure in juvenile zebra finches prior to the appearance of any consistent temporal or acoustic structure in their songs. We found that subsong contains brief inspiratory pulses (50 ms) alternating with longer pulses of sustained expiratory pressure (50-500 ms). In striking contrast to adult song, expiratory pulses often contained multiple (0-8) variably timed syllables separated by expiratory gaps and were only partially vocalized. During development, expiratory pulses became shorter and more stereotyped in duration with shorter and fewer nonvocalized parts. These developmental changes eventually resulted in the production of a single syllable per expiratory pulse and a single inspiratory pulse filling each gap, forming a coordinated sequence similar to that of adult song. To examine the role of forebrain song-control nuclei in the development of respiratory patterns, we performed pressure recordings before and after lesions of nucleus HVC (proper name) and found that this manipulation reverses the developmental trends in measures of the respiratory pattern.

Automatic verification of SSD and generation of respiratory signal with lasers in radiotherapy: a preliminary study.

PubMed

Prabhakar, Ramachandran

2012-01-01

Source to surface distance (SSD) plays a very important role in external beam radiotherapy treatment verification. In this study, a simple technique has been developed to verify the SSD automatically with lasers. The study also suggests a methodology for determining the respiratory signal with lasers. Two lasers, red and green are mounted on the collimator head of a Clinac 2300 C/D linac along with a camera to determine the SSD. A software (SSDLas) was developed to estimate the SSD automatically from the images captured by a 12-megapixel camera. To determine the SSD to a patient surface, the external body contour of the central axis transverse computed tomography (CT) cut is imported into the software. Another important aspect in radiotherapy is the generation of respiratory signal. The changes in the lasers separation as the patient breathes are converted to produce a respiratory signal. Multiple frames of laser images were acquired from the camera mounted on the collimator head and each frame was analyzed with SSDLas to generate the respiratory signal. The SSD as observed with the ODI on the machine and SSD measured by the SSDlas software was found to be within the tolerance limit. The methodology described for generating the respiratory signals will be useful for the treatment of mobile tumors such as lung, liver, breast, pancreas etc. The technique described for determining the SSD and the generation of respiratory signals using lasers is cost effective and simple to implement. Copyright © 2011 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Graded hypoxia acts through a network of distributed peripheral oxygen chemoreceptors to produce changes in respiratory behaviour and plasticity.

PubMed

Janes, Tara A; Xu, Fenglian; Syed, Naweed I

2015-07-01

Respiratory behaviour relies critically upon sensory feedback from peripheral oxygen chemoreceptors. During environmental or systemic hypoxia, chemoreceptor input modulates respiratory central pattern generator activity to produce reflex-based increases in respiration and also shapes respiratory plasticity over longer timescales. The best-studied oxygen chemoreceptors are undoubtedly the mammalian carotid bodies; however, questions remain regarding this complex organ's role in shaping respiration in response to varying oxygen levels. Furthermore, many taxa possess distinct oxygen chemoreceptors located within the lungs, airways and cardiovasculature, but the functional advantage of multiple chemoreceptor sites is unclear. In this study, it is demonstrated that a distributed network of peripheral oxygen chemoreceptors exists in Lymnaea stagnalis and significantly modulates aerial respiration. Specifically, Lymnaea breath frequency and duration represent parameters that are shaped by interactions between hypoxic severity and its time-course. Using a combination of behaviour and electrophysiology approaches, the chemosensory pathways underlying hypoxia-induced changes in breath frequency/duration were explored. The current findings demonstrate that breath frequency is uniquely modulated by the known osphradial ganglion oxygen chemoreceptors during moderate hypoxia, while a newly discovered area of pneumostome oxygen chemoreception serves a similar function specifically during more severe hypoxia. Together, these findings suggest that multiple oxygen chemosensory sites, each with their own sensory and modulatory properties, act synergistically to form a functionally distributed network that dynamically shapes respiration in response to changing systemic or environmental oxygen levels. These distributed networks may represent an evolutionarily conserved strategy vis-à-vis respiratory adaptability and have significant implications for the understanding of fundamental respiratory control systems. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Breathing strategy of the adult horse (Equus caballus) at rest.

PubMed

Koterba, A M; Kosch, P C; Beech, J; Whitlock, T

1988-01-01

To investigate the mechanism underlying the polyphasic airflow pattern of the equine species, we recorded airflow, tidal volum, rib cage and abdominal motion, and the sequence of activation of the diaphragm, intercostal, and abdominal muscles during quiet breathing in nine adult horses standing at rest. In addition, esophageal, abdominal, and transdiaphragmatic pressures were simultaneously recorded using balloon-tipped catheters. Analysis of tidal flow-volume loops showed that, unlike humans, the horse at rest breathes around, rather than from, the relaxed volume of the respiratory system (Vrx). Analysis of the pattern of electromyographic activities and changes in generated pressures during the breathing cycle indicate that the first part of expiration is passive, as in humans, with deflation toward Vrx, but subsequent abdominal activity is responsible for a second phase of expiration: active deflation to below Vrx. From this end-expiratory volume, passive inflation occurs toward Vrx, followed by a second phase of inspiration: active inflation to above Vrx, brought about by inspiratory muscle contraction. Under these conditions the abdominal muscles appear to share the principal pumping duties with the diaphragm. Adoption of this breathing strategy by the horse may relate to its peculiar thoracoabdominal anatomic arrangement and to its very low passive chest wall compliance. We conclude that there is a passive and active phase to both inspiration and expiration due to the coordinated action of the respiratory pump muscles responsible for the resting adult horse's biphasic inspiratory and expiratory airflow pattern. This unique breathing pattern perhaps represents a strategy of minimizing the high elastic work of breathing in this species, at least at resting breathing frequencies.

Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: a digital phantom study.

PubMed

Bernatowicz, K; Keall, P; Mishra, P; Knopf, A; Lomax, A; Kipritidis, J

2015-01-01

Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CT can significantly reduce lung imaging artifacts. Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) "conventional" 4D CT that uses a constant imaging and couch-shift frequency, (ii) "beam paused" 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) "respiratory-gated" 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm(3) spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Averaged across all simulations and phase bins, respiratory-gating reduced overall thoracic MSE by 46% compared to conventional 4D CT (p ∼ 10(-19)). Gating leads to small but significant (p < 0.02) reductions in lung volume errors (1.8%-1.4%), false positives (4.0%-2.6%), and false negatives (2.7%-1.3%). These percentage reductions correspond to gating reducing image artifacts by 24-90 cm(3) of lung tissue. Similar to earlier studies, gating reduced patient image dose by up to 22%, but with scan time increased by up to 135%. Beam paused 4D CT did not significantly impact normal lung tissue image quality, but did yield similar dose reductions as for respiratory-gating, without the added cost in scanning time. For a typical 6 L lung, respiratory-gated 4D CT can reduce image artifacts affecting up to 90 cm(3) of normal lung tissue compared to conventional acquisition. This image improvement could have important implications for dose calculations based on 4D CT. Where image quality is less critical, beam paused 4D CT is a simple strategy to reduce imaging dose without sacrificing acquisition time.

Physiology of respiratory disturbances in muscular dystrophies

PubMed Central

Lo Mauro, Antonella

2016-01-01

Muscular dystrophy is a group of inherited myopathies characterised by progressive skeletal muscle wasting, including of the respiratory muscles. Respiratory failure, i.e. when the respiratory system fails in its gas exchange functions, is a common feature in muscular dystrophy, being the main cause of death, and it is a consequence of lung failure, pump failure or a combination of the two. The former is due to recurrent aspiration, the latter to progressive weakness of respiratory muscles and an increase in the load against which they must contract. In fact, both the resistive and elastic components of the work of breathing increase due to airway obstruction and chest wall and lung stiffening, respectively. The respiratory disturbances in muscular dystrophy are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. They can be present at different rates according to the type of muscular dystrophy and its progression, leading to different onset of each symptom, prognosis and degree of respiratory involvement. Key points A common feature of muscular dystrophy is respiratory failure, i.e. the inability of the respiratory system to provide proper oxygenation and carbon dioxide elimination. In the lung, respiratory failure is caused by recurrent aspiration, and leads to hypoxaemia and hypercarbia. Ventilatory failure in muscular dystrophy is caused by increased respiratory load and respiratory muscles weakness. Respiratory load increases in muscular dystrophy because scoliosis makes chest wall compliance decrease, atelectasis and fibrosis make lung compliance decrease, and airway obstruction makes airway resistance increase. The consequences of respiratory pump failure are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. Educational aims To understand the mechanisms leading to respiratory disturbances in patients with muscular dystrophy. To understand the impact of respiratory disturbances in patients with muscular dystrophy. To provide a brief description of the main forms of muscular dystrophy with their respiratory implications. PMID:28210319

Physiology of respiratory disturbances in muscular dystrophies.

PubMed

Lo Mauro, Antonella; Aliverti, Andrea

2016-12-01

Muscular dystrophy is a group of inherited myopathies characterised by progressive skeletal muscle wasting, including of the respiratory muscles. Respiratory failure, i.e . when the respiratory system fails in its gas exchange functions, is a common feature in muscular dystrophy, being the main cause of death, and it is a consequence of lung failure, pump failure or a combination of the two. The former is due to recurrent aspiration, the latter to progressive weakness of respiratory muscles and an increase in the load against which they must contract. In fact, both the resistive and elastic components of the work of breathing increase due to airway obstruction and chest wall and lung stiffening, respectively. The respiratory disturbances in muscular dystrophy are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. They can be present at different rates according to the type of muscular dystrophy and its progression, leading to different onset of each symptom, prognosis and degree of respiratory involvement. A common feature of muscular dystrophy is respiratory failure, i.e. the inability of the respiratory system to provide proper oxygenation and carbon dioxide elimination.In the lung, respiratory failure is caused by recurrent aspiration, and leads to hypoxaemia and hypercarbia.Ventilatory failure in muscular dystrophy is caused by increased respiratory load and respiratory muscles weakness.Respiratory load increases in muscular dystrophy because scoliosis makes chest wall compliance decrease, atelectasis and fibrosis make lung compliance decrease, and airway obstruction makes airway resistance increase.The consequences of respiratory pump failure are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. To understand the mechanisms leading to respiratory disturbances in patients with muscular dystrophy.To understand the impact of respiratory disturbances in patients with muscular dystrophy.To provide a brief description of the main forms of muscular dystrophy with their respiratory implications.

Robustness of external/internal correlation models for real-time tumor tracking to breathing motion variations

NASA Astrophysics Data System (ADS)

Seregni, M.; Cerveri, P.; Riboldi, M.; Pella, A.; Baroni, G.

2012-11-01

In radiotherapy, organ motion mitigation by means of dynamic tumor tracking requires continuous information about the internal tumor position, which can be estimated relying on external/internal correlation models as a function of external surface surrogates. In this work, we propose a validation of a time-independent artificial neural networks-based tumor tracking method in the presence of changes in the breathing pattern, evaluating the performance on two datasets. First, simulated breathing motion traces were specifically generated to include gradually increasing respiratory irregularities. Then, seven publically available human liver motion traces were analyzed for the assessment of tracking accuracy, whose sensitivity with respect to the structural parameters of the model was also investigated. Results on simulated data showed that the proposed method was not affected by hysteretic target trajectories and it was able to cope with different respiratory irregularities, such as baseline drift and internal/external phase shift. The analysis of the liver motion traces reported an average RMS error equal to 1.10 mm, with five out of seven cases below 1 mm. In conclusion, this validation study proved that the proposed method is able to deal with respiratory irregularities both in controlled and real conditions.

Respiratory Nursing Diagnoses: Presenting Evidence for Identification of the Defining Characteristics in Neonatal and Pediatric Populations.

PubMed

Avena, Marta J; da Luz Gonçalves Pedreira, Mavilde; Herdman, T Heather; Gutiérrez, Maria G R

2016-10-01

To identify and summarize clinical data supporting selection of nursing diagnoses related to the respiratory system for pediatric and neonatal populations. A literature review conducted in indexed publications was used. The final sample consisted of 13 studies conducted in children with cardiac disease, respiratory infection, and asthma with nursing diagnoses such as ineffective breathing pattern, impaired gas exchange, and ineffective airway clearance. The higher frequency defining characteristics were dyspnea, abnormal breathing pattern, use of accessory muscle to breathe, change in frequency and respiratory rate, decreased SaO 2 , and agitation. This literature review may provide a basis for consideration of important diagnostic criteria in the pediatric population; however, clinical validation in different stages of development is critical for ensuring diagnostic accuracy. © 2015 NANDA International, Inc.

Discharge patterns of human tensor palatini motor units during sleep onset.

PubMed

Nicholas, Christian L; Jordan, Amy S; Heckel, Leila; Worsnop, Christopher; Bei, Bei; Saboisky, Julian P; Eckert, Danny J; White, David P; Malhotra, Atul; Trinder, John

2012-05-01

Upper airway muscles such as genioglossus (GG) and tensor palatini (TP) reduce activity at sleep onset. In GG reduced muscle activity is primarily due to inspiratory modulated motor units becoming silent, suggesting reduced respiratory pattern generator (RPG) output. However, unlike GG, TP shows minimal respiratory modulation and presumably has few inspiratory modulated motor units and minimal input from the RPG. Thus, we investigated the mechanism by which TP reduces activity at sleep onset. The activity of TP motor units were studied during relaxed wakefulness and over the transition from wakefulness to sleep. Sleep laboratory. Nine young (21.4 ± 3.4 years) males were studied on a total of 11 nights. Sleep onset. Two TP EMGs (thin, hooked wire electrodes), and sleep and respiratory measures were recorded. One hundred twenty-one sleep onsets were identified (13.4 ± 7.2/subject), resulting in 128 motor units (14.3 ± 13.0/subject); 29% of units were tonic, 43% inspiratory modulated (inspiratory phasic 18%, inspiratory tonic 25%), and 28% expiratory modulated (expiratory phasic 21%, expiratory tonic 7%). There was a reduction in both expiratory and inspiratory modulated units, but not tonic units, at sleep onset. Reduced TP activity was almost entirely due to de-recruitment. TP showed a similar distribution of motor units as other airway muscles. However, a greater proportion of expiratory modulated motor units were active in TP and these expiratory units, along with inspiratory units, tended to become silent over sleep onset. The data suggest that both expiratory and inspiratory drive components from the RPG are reduced at sleep onset in TP.

Temporal and spatial patterns of ambient endotoxin concentrations in Fresno, California.

PubMed

Tager, Ira B; Lurmann, Frederick W; Haight, Thaddeus; Alcorn, Siana; Penfold, Bryan; Hammond, S Katharine

2010-10-01

Endotoxins are found in indoor dust generated by human activity and pets, in soil, and adsorbed onto the surfaces of ambient combustion particles. Endotoxin concentrations have been associated with respiratory symptoms and the risk of atopy and asthma in children. We characterized the temporal and spatial variability of ambient endotoxin in Fresno/Clovis, California, located in California's Central Valley, to identify correlates and potential predictors of ambient endotoxin concentrations in a cohort of children with asthma [Fresno Asthmatic Children's Environment Study (FACES)]. Between May 2001 and October 2004, daily ambient endotoxin and air pollutants were collected at the central ambient monitoring site of the California Air Resources Board in Fresno and, for shorter time periods, at 10 schools and indoors and outdoors at 84 residences in the community. Analyses were restricted to May-October, the dry months during which endotoxin concentrations are highest. Daily endotoxin concentration patterns were determined mainly by meteorologic factors, particularly the degree of air stagnation. Overall concentrations were lowest in areas distant from agricultural activities. Highest concentrations were found in areas immediately downwind from agricultural/pasture land. Among three other measured air pollutants [fine particulate matter, elemental carbon (a marker of traffic in Fresno), and coarse particulate matter (PMc)], PMc was the only pollutant correlated with endotoxin. Endotoxin, however, was the most spatially variable. Our data support the need to evaluate the spatial/temporal variability of endotoxin concentrations, rather than relying on a few measurements made at one location, in studies of exposure and and respiratory health effects, particularly in children with asthma and other chronic respiratory diseases.

Lung Ultrasound Pattern Is Normal during the Last Gestational Weeks: An Observational Pilot Study.

PubMed

Arbeid, Erik; Demi, Alessio; Brogi, Etrusca; Gori, Elisa; Giusto, Teresa; Soldati, Gino; Vetrugno, Luigi; Giunta, Francesco; Forfori, Francesco

2017-01-01

The normal lung ultrasound (US) pattern during a regular pregnancy has not been evaluated extensively in the current literature. Pregnancy-related changes in the respiratory tract affect maternal predisposition to several respiratory complications; consequently, it is important to differentiate between a physiologic pattern during pregnancy and a pathologic lung pattern, due to respiratory failure. The goal of our study was to assess the normal US lung pattern in women without known comorbidities in the last weeks of pregnancy. We conducted a prospective cross-sectional observational pilot study. Chest wall was examined in 8 areas, 1 scan for each area with women in supine position. One hundred fifty parturients were enrolled during the 36th-38th gestational weeks. None of the participants showed pleural effusion, pneumothorax or lung consolidation. None presented an interstitial syndrome US pattern. One hundred thirteen participants out of 150 (75%) showed A-lines in all the regions. The remaining 25% showed 1 or 2 B-lines in at least 3 regions. Only 2 participants showed 2 positive regions also. We found that, in the majority of the women examined, the lung US pattern matches the physiological pattern in non-pregnant patients. Lung US assessment is a feasible and a helpful diagnostic tool during pregnancy. © 2016 S. Karger AG, Basel.

Study of the distribution patterns of the constituent herbs in classical Chinese medicine prescriptions treating respiratory disease by data mining methods.

PubMed

Fu, Xian-Jun; Song, Xu-Xia; Wei, Lin-Bo; Wang, Zhen-Guo

2013-08-01

To provide the distribution pattern and compatibility laws of the constituent herbs in prescriptions, for doctor's convenience to make decision in choosing correct herbs and prescriptions for treating respiratory disease. Classical prescriptions treating respiratory disease were selected from authoritative prescription books. Data mining methods (frequent itemsets and association rules) were used to analyze the regular patterns and compatibility laws of the constituent herbs in the selected prescriptions. A total of 562 prescriptions were selected to be studied. The result exhibited that, Radix glycyrrhizae was the most frequently used in 47.2% prescriptions, other frequently used were Semen armeniacae amarum, Fructus schisandrae Chinese, Herba ephedrae, and Radix ginseng. Herbal ephedrae was always coupled with Semen armeniacae amarum with the confidence of 73.3%, and many herbs were always accompanied by Radix glycyrrhizae with high confidence. More over, Fructus schisandrae Chinese, Herba ephedrae and Rhizoma pinelliae was most commonly used to treat cough, dyspnoea and associated sputum respectively besides Radix glycyrrhizae and Semen armeniacae amarum. The prescriptions treating dyspnoea often used double herb group of Herba ephedrae & Radix glycyrrhizae, while prescriptions treating sputum often used double herb group of Rhizoma pinelliae & Radix glycyrrhizae and Rhizoma pinelliae & Semen armeniacae amarum, triple herb groups of Rhizoma pinelliae & Semen armeniacae amarum & Radix glycyrrhizae and Pericarpium citri reticulatae & Rhizoma pinelliae & Radix glycyrrhizae. The prescriptions treating respiratory disease showed common compatibility laws in using herbs and special compatibility laws for treating different respiratory symptoms. These principle patterns and special compatibility laws reported here could be useful for doctors to choose correct herbs and prescriptions in treating respiratory disease.

Continuous on-line measurements of respiratory system, lung and chest wall mechanics during mechanic ventilation.

PubMed

Kárason, S; Søndergaard, S; Lundin, S; Stenqvist, O

2001-08-01

We present a concept of on-line, manoeuvre-free monitoring of respiratory mechanics during dynamic conditions, displaying calculated alveolar pressure/volume curves continuously and separating lung and chest wall mechanics. Prospective observational study. Intensive care unit of a university hospital. Ten ventilator-treated patients with acute lung injury. Different positive end-expiratory pressure (PEEP) and tidal volumes, low flow inflation. Previously validated methods were used to present a single-value dynostatic compliance for the whole breath and a dynostatic volume-dependent initial, middle and final compliance within the breath. A high individual variation of respiratory mechanics was observed. Reproducibility of repeated measurements was satisfactory (coefficients of variations for dynostatic volume-dependent compliance: < or =9.2% for total respiratory system, < or =18% for lung). Volume-dependent compliance showed a statistically significant pattern of successively decreasing compliance from the initial segment through the middle and final parts within each breath at all respiratory settings. This pattern became more prominent with increasing PEEP and tidal volume, indicating a greater distension of alveoli. No lower inflection point (LIP) was seen in patients with respiratory rate 20/min and PEEP at 4 cmH2O. A trial with low flow inflation in four of the patients showed formation of a LIP in three of them and an upper inflection in one. The monitoring concept revealed a constant pattern of successively decreasing compliance within each breath, which became more prominent with increasing PEEP and tidal volume. The monitoring concept offers a simple and reliable method of monitoring respiratory mechanics during ongoing ventilator treatment.

Effect of exposure to fentanyl aerosol in mice on breathing pattern and respiratory variables.

PubMed

Manral, Laxmi; Muniappan, Natrajan; Gupta, Pradeep K; Ganesan, Kumaran; Malhotra, Ramesh Chandra; Vijayaraghavan, Rajagopalan

2009-01-01

The breathing pattern of mice that were exposed to fentanyl aerosol was studied (2.7, 5.7, 6.0, 10.0, and 23.6 microg/m(3); for 1 hour), using dimethyl sulfoxide as a vehicle. This study was conducted in a head-only exposure assembly. Body plethysmographs connected to a volumetric pressure transducer were used to capture the respiratory signals, and an on-line computer program capable of recognizing the changes in the breathing pattern was used for monitoring the respiratory pattern. The response of mice to fentanyl exposure was found to be concentration dependent. A lower concentration (2.7 microg/m(3)) showed fast recovery and no mortality, while 100% mortality was observed at a higher concentration (23.6 microg/m(3)). No sensory, pulmonary irritation, and airway limitation in mice was observed, and death occurred probably due to respiratory depression. The concentration that decreased 50% of the respiratory frequency (RD(50)) was estimated to be 6.4 microg/m(3). The extrapolated human threshold limit value, calculated from the RD(50) value, was found to be 0.192 microg/m(3). The concentration that caused 50% mortality in exposed mice (LC(50)) was estimated to be 8.8 microg/m(3). This study shows that aerosolized fentanyl does not cause sensory and pulmonary irritation, and since the RD(50) and LC(50) are very close with a low safety margin, this type of sedative should not be used as an incapacitating agent.

Vagal-dependent nonlinear variability in the respiratory pattern of anesthetized, spontaneously breathing rats

PubMed Central

Dhingra, R. R.; Jacono, F. J.; Fishman, M.; Loparo, K. A.; Rybak, I. A.

2011-01-01

Physiological rhythms, including respiration, exhibit endogenous variability associated with health, and deviations from this are associated with disease. Specific changes in the linear and nonlinear sources of breathing variability have not been investigated. In this study, we used information theory-based techniques, combined with surrogate data testing, to quantify and characterize the vagal-dependent nonlinear pattern variability in urethane-anesthetized, spontaneously breathing adult rats. Surrogate data sets preserved the amplitude distribution and linear correlations of the original data set, but nonlinear correlation structure in the data was removed. Differences in mutual information and sample entropy between original and surrogate data sets indicated the presence of deterministic nonlinear or stochastic non-Gaussian variability. With vagi intact (n = 11), the respiratory cycle exhibited significant nonlinear behavior in templates of points separated by time delays ranging from one sample to one cycle length. After vagotomy (n = 6), even though nonlinear variability was reduced significantly, nonlinear properties were still evident at various time delays. Nonlinear deterministic variability did not change further after subsequent bilateral microinjection of MK-801, an N-methyl-d-aspartate receptor antagonist, in the Kölliker-Fuse nuclei. Reversing the sequence (n = 5), blocking N-methyl-d-aspartate receptors bilaterally in the dorsolateral pons significantly decreased nonlinear variability in the respiratory pattern, even with the vagi intact, and subsequent vagotomy did not change nonlinear variability. Thus both vagal and dorsolateral pontine influences contribute to nonlinear respiratory pattern variability. Furthermore, breathing dynamics of the intact system are mutually dependent on vagal and pontine sources of nonlinear complexity. Understanding the structure and modulation of variability provides insight into disease effects on respiratory patterning. PMID:21527661

Discharge Patterns of Human Tensor Palatini Motor Units During Sleep Onset

PubMed Central

Nicholas, Christian L.; Jordan, Amy S.; Heckel, Leila; Worsnop, Christopher; Bei, Bei; Saboisky, Julian P.; Eckert, Danny J.; White, David P.; Malhotra, Atul; Trinder, John

2012-01-01

Study Objectives: Upper airway muscles such as genioglossus (GG) and tensor palatini (TP) reduce activity at sleep onset. In GG reduced muscle activity is primarily due to inspiratory modulated motor units becoming silent, suggesting reduced respiratory pattern generator (RPG) output. However, unlike GG, TP shows minimal respiratory modulation and presumably has few inspiratory modulated motor units and minimal input from the RPG. Thus, we investigated the mechanism by which TP reduces activity at sleep onset. Design: The activity of TP motor units were studied during relaxed wakefulness and over the transition from wakefulness to sleep. Setting: Sleep laboratory. Participants: Nine young (21.4 ± 3.4 years) males were studied on a total of 11 nights. Intervention: Sleep onset. Measurements and Results: Two TP EMGs (thin, hooked wire electrodes), and sleep and respiratory measures were recorded. One hundred twenty-one sleep onsets were identified (13.4 ± 7.2/subject), resulting in 128 motor units (14.3 ± 13.0/subject); 29% of units were tonic, 43% inspiratory modulated (inspiratory phasic 18%, inspiratory tonic 25%), and 28% expiratory modulated (expiratory phasic 21%, expiratory tonic 7%). There was a reduction in both expiratory and inspiratory modulated units, but not tonic units, at sleep onset. Reduced TP activity was almost entirely due to de-recruitment. Conclusions: TP showed a similar distribution of motor units as other airway muscles. However, a greater proportion of expiratory modulated motor units were active in TP and these expiratory units, along with inspiratory units, tended to become silent over sleep onset. The data suggest that both expiratory and inspiratory drive components from the RPG are reduced at sleep onset in TP. Citation: Nicholas CL; Jordan AS; Heckel L; Worsnop C; Bei B: Saboisky JP; Eckert DJ; White DP; Malhotra A; Trinder J. Discharge patterns of human tensor palatini motor units during sleep onset. SLEEP 2012;35(5):699-707. PMID:22547896

Detection of severe respiratory disease epidemic outbreaks by CUSUM-based overcrowd-severe-respiratory-disease-index model.

PubMed

Polanco, Carlos; Castañón-González, Jorge Alberto; Macías, Alejandro E; Samaniego, José Lino; Buhse, Thomas; Villanueva-Martínez, Sebastián

2013-01-01

A severe respiratory disease epidemic outbreak correlates with a high demand of specific supplies and specialized personnel to hold it back in a wide region or set of regions; these supplies would be beds, storage areas, hemodynamic monitors, and mechanical ventilators, as well as physicians, respiratory technicians, and specialized nurses. We describe an online cumulative sum based model named Overcrowd-Severe-Respiratory-Disease-Index based on the Modified Overcrowd Index that simultaneously monitors and informs the demand of those supplies and personnel in a healthcare network generating early warnings of severe respiratory disease epidemic outbreaks through the interpretation of such variables. A post hoc historical archive is generated, helping physicians in charge to improve the transit and future allocation of supplies in the entire hospital network during the outbreak. The model was thoroughly verified in a virtual scenario, generating multiple epidemic outbreaks in a 6-year span for a 13-hospital network. When it was superimposed over the H1N1 influenza outbreak census (2008-2010) taken by the National Institute of Medical Sciences and Nutrition Salvador Zubiran in Mexico City, it showed that it is an effective algorithm to notify early warnings of severe respiratory disease epidemic outbreaks with a minimal rate of false alerts.

Detection of Severe Respiratory Disease Epidemic Outbreaks by CUSUM-Based Overcrowd-Severe-Respiratory-Disease-Index Model

PubMed Central

Castañón-González, Jorge Alberto; Macías, Alejandro E.; Samaniego, José Lino; Buhse, Thomas; Villanueva-Martínez, Sebastián

2013-01-01

A severe respiratory disease epidemic outbreak correlates with a high demand of specific supplies and specialized personnel to hold it back in a wide region or set of regions; these supplies would be beds, storage areas, hemodynamic monitors, and mechanical ventilators, as well as physicians, respiratory technicians, and specialized nurses. We describe an online cumulative sum based model named Overcrowd-Severe-Respiratory-Disease-Index based on the Modified Overcrowd Index that simultaneously monitors and informs the demand of those supplies and personnel in a healthcare network generating early warnings of severe respiratory disease epidemic outbreaks through the interpretation of such variables. A post hoc historical archive is generated, helping physicians in charge to improve the transit and future allocation of supplies in the entire hospital network during the outbreak. The model was thoroughly verified in a virtual scenario, generating multiple epidemic outbreaks in a 6-year span for a 13-hospital network. When it was superimposed over the H1N1 influenza outbreak census (2008–2010) taken by the National Institute of Medical Sciences and Nutrition Salvador Zubiran in Mexico City, it showed that it is an effective algorithm to notify early warnings of severe respiratory disease epidemic outbreaks with a minimal rate of false alerts. PMID:24069063

Attend or defend? Sex differences in behavioral, autonomic, and respiratory response patterns to emotion-eliciting films.

PubMed

Wilhelm, Frank H; Rattel, Julina A; Wegerer, Melanie; Liedlgruber, Michael; Schweighofer, Simon; Kreibig, Sylvia D; Kolodyazhniy, Vitaliy; Blechert, Jens

2017-12-01

Sex differences in emotional reactivity have been studied primarily for negative but less so for positive stimuli; likewise, sex differences in the psychophysiological response-patterning during such stimuli are poorly understood. Thus, the present study examined sex differences in response to negative/positive and high/low arousing films (classified as threat-, loss-, achievement-, and recreation-related, vs. neutral films), while measuring 18 muscular, autonomic, and respiratory parameters. Sex differences emerged for all films, but were most prominent for threat-related films: Despite equivalent valence and arousal ratings, women displayed more facial-muscular and respiratory responding than men and pronounced sympathetic activation (preejection period, other cardiovascular and electrodermal measures), while men showed coactivated sympathetic/parasympathetic responding (including increased respiratory sinus arrhythmia). This indicates a prototypical threat-related defense response in women, while men showed a pattern of sustained orienting, which can be understood as a shift toward less threat proximity in the defense cascade model. Clinical implications are discussed within a socio-evolutionary framework. Copyright © 2017 Elsevier B.V. All rights reserved.

Smart textile for respiratory monitoring and thoraco-abdominal motion pattern evaluation.

PubMed

Massaroni, Carlo; Venanzi, Cecilia; Silvatti, Amanda P; Lo Presti, Daniela; Saccomandi, Paola; Formica, Domenico; Giurazza, Francesco; Caponero, Michele A; Schena, Emiliano

2018-05-01

The use of wearable systems for monitoring vital parameters has gained wide popularity in several medical fields. The focus of the present study is the experimental assessment of a smart textile based on 12 fiber Bragg grating sensors for breathing monitoring and thoraco-abdominal motion pattern analysis. The feasibility of the smart textile for monitoring several temporal respiratory parameters (ie, breath-by-breath respiratory period, breathing frequency, duration of inspiratory and expiratory phases), volume variations of the whole chest wall and of its compartments is performed on 8 healthy male volunteers. Values gathered by the textile are compared to the data obtained by a motion analysis system, used as the reference instrument. Good agreement between the 2 systems on both respiratory period (bias of 0.01 seconds), breathing frequency (bias of -0.02 breaths/min) and tidal volume (bias of 0.09 L) values is demonstrated. Smart textile shows good performance in the monitoring of thoraco-abdominal pattern and its variation, as well. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inspiratory High Frequency Airway Oscillation Attenuates Resistive Loaded Dyspnea and Modulates Respiratory Function in Young Healthy Individuals

PubMed Central

Morris, Theresa; Sumners, David Paul; Green, David Andrew

2014-01-01

Direct chest-wall percussion can reduce breathlessness in Chronic Obstructive Pulmonary Disease and respiratory function may be improved, in health and disease, by respiratory muscle training (RMT). We tested whether high-frequency airway oscillation (HFAO), a novel form of airflow oscillation generation can modulate induced dyspnoea and respiratory strength and/or patterns following 5 weeks of HFAO training (n = 20) compared to a SHAM-RMT (conventional flow-resistive RMT) device (n = 15) in healthy volunteers (13 males; aged 20–36 yrs). HFAO causes oscillations with peak-to-peak amplitude of 1 cm H2O, whereas the SHAM-RMT device was identical but created no pressure oscillation. Respiratory function, dyspnoea and ventilation during 3 minutes of spontaneous resting ventilation, 1 minute of maximal voluntary hyperventilation and 1 minute breathing against a moderate inspiratory resistance, were compared PRE and POST 5-weeks of training (2×30 breaths at 70% peak flow, 5 days a week). Training significantly reduced NRS dyspnoea scores during resistive loaded ventilation, both in the HFAO (p = 0.003) and SHAM-RMT (p = 0.005) groups. Maximum inspiratory static pressure (cm H2O) was significantly increased by HFAO training (vs. PRE; p<0.001). Maximum inspiratory dynamic pressure was increased by training in both the HFAO (vs. PRE; p<0.001) and SHAM-RMT (vs. PRE; p = 0.021) groups. Peak inspiratory flow rate (L.s−1) achieved during the maximum inspiratory dynamic pressure manoeuvre increased significantly POST (vs. PRE; p = 0.001) in the HFAO group only. HFAO reduced inspiratory resistive loading–induced dyspnoea and augments static and dynamic maximal respiratory manoeuvre performance in excess of flow-resistive IMT (SHAM-RMT) in healthy individuals without the respiratory discomfort associated with RMT. PMID:24651392

Structure of a human pulmonary acinus.

PubMed

Berend, N; Rynell, A C; Ward, H E

1991-02-01

The structure of the human pulmonary acinus has been described infrequently. The aim of the study was to determine the branching pattern of respiratory bronchioles and alveolar ducts in a human acinus from the peripheral part of the lung, where space constraints may have affected airway branching patterns. The lungs were obtained from an 18 year old victim of a motor vehicle accident and fixed in inflation under a pressure of 25 cm H2O. A block was cut from the lower edge of the right lower lobe and embedded in plastic. Serial sections were cut and the branching pattern of airways subtended by a terminal bronchiole were followed. The acinus was bounded on two sides by pleura and on the remaining sides by connective tissue septa. The terminal bronchiole divided into two respiratory bronchioles, each of which gave rise to four systems of alveolar ducts. Between successive systems of alveolar ducts the respiratory bronchioles continued as single airways, becoming progressively more alveolated towards the periphery but not subtending further branches of respiratory bronchioles. The duct systems became less complex towards the periphery, near to the edge of the lung. The total volume of the acinus was similar to that found in previous studies. This branching pattern has not been described previously in a human acinus.

Numerical investigation of diesel exhaust particle transport and deposition in the CT-scan based lung airway

NASA Astrophysics Data System (ADS)

Islam, Mohammad S.; Saha, Suvash C.; Sauret, Emilie; Gu, Y. T.; Molla, Md Mamun

2017-06-01

Diesel exhaust particulates matter (DEPM) is a compound mixture of gasses and fine particles that contain more than 40 toxic air pollutants including benzene, formaldehyde, and nitrogen oxides. Exposure of DEPM to human lung airway during respiratory inhalation causes severe health hazards like diverse pulmonary diseases. This paper studies the DEPM transport and deposition in upper three generations of the realistic lung airways. A 3-D digital airway bifurcation model is constructed from the computerized tomography (CT) scan data of a healthy adult man. The Euler-Lagrange approach is used to solve the continuum and disperse phases of the calculation. Local averaged Navier-Stokes equations are solved to calculate the transport of the continuum phase. Lagrangian based Discrete Phase Model (DPM) is used to investigate the particle transport and deposition in the current anatomical model. The effects of size specific monodispersed particles on deposition are extensively investigated during different breathing pattern. The numerical results illustrate that particle diameter and breathing pattern have a substantial impact on particles transport and deposition in the tracheobronchial airways. The present realistic bifurcation model also depicts a new deposition hot spot which could advance the understanding of the therapeutic drug delivery system to the specific position of the respiratory airways.

Effect of the bifurcation angle on the flow within a synthetic model of lower human airways

NASA Astrophysics Data System (ADS)

Espinosa Moreno, Andres Santiago; Duque Daza, Carlos Alberto

2016-11-01

The effect of the bifurcation angle on the flow pattern developed during respiratory inhalation and exhalation processes was explored numerically using a synthetic model of lower human airways featuring three generations of a dichotomous morphology as described by a Weibel model. Laminar flow simulations were performed for six bifurcation angles and four Reynolds numbers relevant to human respiratory flow. Numerical results of the inhalation process showed a peak displacement trend of the velocity profile towards the inner walls of the model. This displacement exhibited correlation with Dean-type secondary flow patterns, as well as with the onset and location of vortices. High wall shear stress regions on the inner walls were observed for a range of bifurcation angles. Noteworthy, specific bifurcation angles produced higher values of pressure drop, compared to the average behavior, as well as changes in the volumetric flow through the branches. Results of the simulations for exhalation process showed a different picture, mainly the appearance of symmetrical velocity profiles and the change of location of the regions of high wall shear stress. The use of this modelling methodology for biomedical applications is discussed considering the validity of the obtained results. Department of Mechanical and Mechatronics Engineering, Universidad Nacional de Colombia.

Scoring Tools for the Analysis of Infant Respiratory Inductive Plethysmography Signals.

PubMed

Robles-Rubio, Carlos Alejandro; Bertolizio, Gianluca; Brown, Karen A; Kearney, Robert E

2015-01-01

Infants recovering from anesthesia are at risk of life threatening Postoperative Apnea (POA). POA events are rare, and so the study of POA requires the analysis of long cardiorespiratory records. Manual scoring is the preferred method of analysis for these data, but it is limited by low intra- and inter-scorer repeatability. Furthermore, recommended scoring rules do not provide a comprehensive description of the respiratory patterns. This work describes a set of manual scoring tools that address these limitations. These tools include: (i) a set of definitions and scoring rules for 6 mutually exclusive, unique patterns that fully characterize infant respiratory inductive plethysmography (RIP) signals; (ii) RIPScore, a graphical, manual scoring software to apply these rules to infant data; (iii) a library of data segments representing each of the 6 patterns; (iv) a fully automated, interactive formal training protocol to standardize the analysis and establish intra- and inter-scorer repeatability; and (v) a quality control method to monitor scorer ongoing performance over time. To evaluate these tools, three scorers from varied backgrounds were recruited and trained to reach a performance level similar to that of an expert. These scorers used RIPScore to analyze data from infants at risk of POA in two separate, independent instances. Scorers performed with high accuracy and consistency, analyzed data efficiently, had very good intra- and inter-scorer repeatability, and exhibited only minor confusion between patterns. These results indicate that our tools represent an excellent method for the analysis of respiratory patterns in long data records. Although the tools were developed for the study of POA, their use extends to any study of respiratory patterns using RIP (e.g., sleep apnea, extubation readiness). Moreover, by establishing and monitoring scorer repeatability, our tools enable the analysis of large data sets by multiple scorers, which is essential for longitudinal and multicenter studies.

Dysrhythmias of the respiratory oscillator

NASA Astrophysics Data System (ADS)

Paydarfar, David; Buerkel, Daniel M.

1995-03-01

Breathing is regulated by a central neural oscillator that produces rhythmic output to the respiratory muscles. Pathological disturbances in rhythm (dysrhythmias) are observed in the breathing pattern of children and adults with neurological and cardiopulmonary diseases. The mechanisms responsible for genesis of respiratory dysrhythmias are poorly understood. The present studies take a novel approach to this problem. The basic postulate is that the rhythm of the respiratory oscillator can be altered by a variety of stimuli. When the oscillator recovers its rhythm after such perturbations, its phase may be reset relative to the original rhythm. The amount of phase resetting is dependent upon stimulus parameters and the level of respiratory drive. The long-range hypothesis is that respiratory dysrhythmias can be induced by stimuli that impinge upon or arise within the respiratory oscillator with certain combinations of strength and timing relative to the respiratory cycle. Animal studies were performed in anesthetized or decerebrate preparations. Neural respiratory rhythmicity is represented by phrenic nerve activity, allowing use of open-loop experimental conditions which avoid negative chemical feedback associated with changes in ventilation. In animal experiments, respiratory dysrhythmias can be induced by stimuli having specific combinations of strength and timing. Newborn animals readily exhibit spontaneous dysrhythmias which become more prominent at lower respiratory drives. In human subjects, swallowing was studied as a physiological perturbation of respiratory rhythm, causing a pattern of phase resetting that is characterized topologically as type 0. Computational studies of the Bonhoeffer-van der Pol (BvP) equations, whose qualitative behavior is representative of many excitable systems, supports a unified interpretation of these experimental findings. Rhythmicity is observed when the BvP model exhibits recurrent periods of excitation alternating with refractory periods. The same system can be perturbed to a state in which amplitude of oscillation is attenuated or abolished. We have characterized critical perturbations which induce transitions between these two states, giving rise to patterns of dysrhythmic activity that are similar to those seen in the experiments. We illustrate the importance of noise in initiation and termination of rhythm, comparable to normal respiratory rhythm intermixed with spontaneous dysrhythmias. In the BvP system the incidence and duration of dysrhythmia is shown to be strongly influenced by the level of noise. These studies should lead to greater understanding of rhythmicity and integrative responses of the respiratory control system, and provide insight into disturbances in control mechanisms that cause apnea and aspiration in clinical disease states.

Pattern of respiratory diseases in children presenting to the paediatric emergency unit of the University of Nigeria Teaching Hospital, Enugu: a case series report.

PubMed

Oguonu, Tagbo; Adaeze Ayuk, Chikaodinaka; Edelu, Benedict Onyeka; Ndu, Ikenna Kingsley

2014-06-10

Respiratory diseases are one of the causes of childhood morbidity and mortality as well as hospitalization globally. The patterns of different respiratory illnesses in several parts of the world have been reported but there are few on the combined burden of the diseases. Determination of the burden of respiratory diseases as a group will help ascertain their collective impact on the health systems in order to develop intervention measures. Data from case notes of children with respiratory diseases admitted to the University of Nigeria Teaching Hospital Enugu, Nigeria over a six year period were extracted. Age, gender, admission rates, types of respiratory illness, duration of admission, season of presentation and outcome were analysed. Descriptive and inferential (Chi square) statistics were used to describe the various disease types and ascertain association of the disease outcome, seasonal pattern with the types of diseases. Of the total of 8974 children admissions, 2214 (24.7%) were due to respiratory diseases. The mean age of all the children with respiratory diseases was 3.3 years (SD 3.9). Communicable diseases were the common cause of admission cases throughout the seasons, p < 0.001. The highest admission rates were for pneumonia, (34.0%), acute bronchial asthma, (27.7%) and rhinosinusitis (14.6%) p < 0.001. The frequency of respiratory disease decreases with age and children less than five years of age and of low socio-economic status were commonly affected, p=0.01. The median duration of hospital stay was two days [range 1 to 8 days], children less than five years old and those of low socio-economic status, spent more than four days (p=0.01 and p < 0.001 respectively). The all-cause mortality was 0.5% (11/2214) of which 81.8% (9/11) was due to pneumonia. Respiratory diseases constitute a significant burden of childhood illnesses in our centre. Efforts are required to reduce the impact as part of the steps towards the achievement of the Millennium Development Goals.

[Antibiotic prescribing in acute respiratory tract infections in general practice].

PubMed

Malo, S; Bjerrum, L; Feja, C; Lallana, M J; Poncel, A; Rabanaque, M J

2015-06-01

Antimicrobial resistance is a worldwide threat to public health. Acute respiratory tract infections are the main reason for antibiotic prescribing in the Spanish paediatric population. The aim of the study was to describe the frequency of antibiotic prescription and their pattern of use in acute respiratory tract infections diagnosed in children in Primary Care in Aragón (Spain). A study was conducted over a 1-year period on children between 0 and 14 years-old, recording all episodes of acute otitis, acute pharyngotonsillitis, non-specific upper respiratory infection, and acute bronchitis. The proportion of episodes within each diagnosis receiving an antibiotic prescription was calculated, and the prescribing pattern was determined. Half (50%) of the children in Aragón were diagnosed with a respiratory tract infection during the study period. Non-specific upper respiratory infection was the most frequent diagnosis. An antibiotic was prescribed in 75% of pharyngotonsillitis episodes, 72% of otitis, 27% of bronchitis, and 16% of non-specific upper respiratory infections. Broad spectrum antibiotics, mainly amoxicillin and amoxicillin-clavulanic, were predominantly prescribed. Antibiotic prescribing in respiratory tract infections in children was generally high, and the choice of antibiotics was probably inappropriate in a high percentage of cases. Therefore an improvement in antibiotic prescribing in children appears to be needed. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

Prevalence and seasonality of six respiratory viruses during five consecutive epidemic seasons in Belgium.

PubMed

Ramaekers, Kaat; Keyaerts, Els; Rector, Annabel; Borremans, Annie; Beuselinck, Kurt; Lagrou, Katrien; Van Ranst, Marc

2017-09-01

Acute Respiratory Infections (ARIs) are a major health problem, especially in young children and the elderly. Insights into the seasonality of respiratory viruses can help us understand when the burden on society is highest and which age groups are most vulnerable. We monitored six respiratory viruses during five consecutive seasons (2011-2016) in Belgium. Patient specimens (n=22876), tested for one or more of the following respiratory viruses, were included in this analysis: Influenza viruses (IAV & IBV), Human respiratory syncytial virus (hRSV), Human metapneumovirus (hMPV), Adenovirus (ADV) and Human parainfluenza virus (hPIV). Data were analysed for four age categories: <6y, 6-17y, 18-64y and ≥65y. Children <6y had the highest infection rates (39% positive vs. 20% positive adults) and the highest frequency of co-infections. hRSV (28%) and IAV (32%) caused the most common respiratory viral infections and followed, like hMPV, a seasonal pattern with winter peaks. hRSV followed an annual pattern with two peaks: first in young children and ±7 weeks later in elderly. This phenomenon has not been described in literature so far. hPIV and ADV occurred throughout the year with higher rates in winter. Children <6y are most vulnerable for respiratory viral infections and have a higher risk for co-infections. hRSV and IAV are the most common respiratory infections with peaks during the winter season in Belgium. Copyright © 2017 Elsevier B.V. All rights reserved.

Neural breathing patterns in preterm newborns supported with non-invasive neurally adjusted ventilatory assist.

PubMed

García-Muñoz Rodrigo, Fermín; Urquía Martí, Lourdes; Galán Henríquez, Gloria; Rivero Rodríguez, Sonia; Hernández Gómez, Alberto

2018-06-18

To characterize the neural breathing pattern in preterm infants supported with non-invasive neurally adjusted ventilatory assist (NIV-NAVA). Single-center prospective observational study. The electrical activity of the diaphragm (EAdi) was periodically recorded in 30-second series with the Edi catheter and the Servo-n software (Maquet, Solna, Sweden) in preterm infants supported with NIV-NAVA. The EAdi Peak , EAdi Min , EAdi Tonic , EAdi Phasic , neural inspiratory, and expiratory times (nTi and nTe) and the neural respiratory rate (nRR) were calculated. EAdi curves were generated by Excel for visual examination and classified according to the predominant pattern. 291 observations were analyzed in 19 patients with a mean GA of 27.3 weeks (range 24-36 weeks), birth weight 1028 g (510-2945 g), and a median (IQR) postnatal age of 18 days (4-27 days). The distribution of respiratory patterns was phasic without tonic activity 61.9%, phasic with basal tonic activity 18.6, tonic burst 3.8%, central apnea 7.9%, and mixed pattern 7.9%. In addition, 12% of the records showed apneas of >10 seconds, and 50.2% one or more "sighs", defined as breaths with an EAdi Peak and/or nTi greater than twice the average EAdi Peak and/or nTi of the recording. Neural times were measurable in 252 observations. The nTi was, median (IQR): 279 ms (253-285 ms), the nTe 764 ms (642-925 ms), and the nRR 63 bpm (51-70), with a great intra and inter-subjects variability. The neural breathing patterns in preterm infants supported with NIV-NAVA are quite variable and are characterized by the presence of significant tonic activity. Central apneas and sighs are common in this group of patients. The nTi seems to be shorter than the mechanical Ti commonly used in assisted ventilation.

Central pattern generation involved in oral and respiratory control for feeding in the term infant

PubMed Central

Barlow, Steven M.

2009-01-01

Purpose of review Drinking and eating are essential skills for survival and benefit from the coordination of several pattern generating networks and their musculoskeletal effectors to achieve safe swallows. Oral-pharyngo-esophageal motility develops during infancy and early childhood, and is influenced by various factors, including neuromuscular maturation, dietary and postural habits, arousal state, ongoing illnesses, congenital anomalies, and the effects of medical or surgical interventions. Gastroesophageal reflux is frequent in neonates and infants, and its role in neonatal morbidity including dysphagia, chronic lung disease, or apparent life-threatening events is not well understood. This review highlights recent studies aimed at understanding the development of oral feeding skills, and cross-system interactions among the brainstem, spinal, and cerebral networks involved in feeding. Recent Findings Functional linkages between suck-swallow and swallow-respiration manifest transitional forms during late gestation through the first year of life which can be delayed or modified by sensory experience and/or disease processes. Relevant central pattern generator (CPG) networks and their neuromuscular targets attain functional status at different rates, which ultimately influences cross-system CPG interactions. Entrainment of trigeminal primary afferents accelerates pattern genesis for the suck CPG and transition-to-oral feed in the RDS preterm infant. Summary The genesis of within-system CPG control for rate and amplitude scaling matures differentially for suck, mastication, swallow, and respiration. Cross-system interactions among these CPGs represent targets of opportunity for new interventions which optimize experience-dependent mechanisms to promote safe swallows among newborn and pediatric patients. PMID:19417662

Loss of CDKL5 disrupts respiratory function in mice.

PubMed

Lee, Kun-Ze; Liao, Wenlin

2018-01-01

Cyclin-dependent kinase-like 5 (CDKL5) is an X-linked gene encoding a serine-threonine kinase that is highly expressed in the central nervous system. Mutations in CDKL5 cause neurological and psychiatric symptoms, including early-onset seizures, motor dysfunction, autistic features and sleep breathing abnormalities in patients. It remains to be addressed whether loss of CDKL5 causes respiratory dysfunction in mice. Here, we examined the respiratory pattern of male Cdkl5 -/y mice at 1-3 months of age during resting breathing and respiratory challenge (i.e., hypoxia and hypercapnia) via whole body plethysmography. The results demonstrated that the resting respiratory frequency and tidal volume of Cdkl5 -/y mice was unaltered compared to that of WT mice at 1 month of age. However, these mutant mice exhibit transient reduction in tidal volume during respiratory challenge even the reduction was restored at 2 months of age. Notably, the sigh-breathing pattern was changed in Cdkl5 -/y mice, showing a transient reduction in sigh volume at 1-2 month of age and long-term attenuation of peak expiratory airflow from 1 to 3 month of age. Therefore, loss of CDKL5 causes breathing deficiency, supporting a CDKL5-mediated regulation of respiratory function in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

The mechanisms underlying the production of discontinuous gas exchange cycles in insects.

PubMed

Matthews, Philip G D

2018-03-01

This review examines the control of gas exchange in insects, specifically examining what mechanisms could explain the emergence of discontinuous gas exchange cycles (DGCs). DGCs are gas exchange patterns consisting of alternating breath-hold periods and bouts of gas exchange. While all insects are capable of displaying a continuous pattern of gas exchange, this episodic pattern is known to occur within only some groups of insects and then only sporadically or during certain phases of their life cycle. Investigations into DGCs have tended to emphasise the role of chemosensory thresholds in triggering spiracle opening as critical for producing these gas exchange patterns. However, a chemosensory basis for episodic breathing also requires an as-of-yet unidentified hysteresis between internal respiratory stimuli, chemoreceptors, and the spiracles. What has been less appreciated is the role that the insect's central nervous system (CNS) might play in generating episodic patterns of ventilation. The active ventilation displayed by many insects during DGCs suggests that this pattern could be the product of directed control by the CNS rather than arising passively as a result of self-sustaining oscillations in internal oxygen and carbon dioxide levels. This paper attempts to summarise what is currently known about insect gas exchange regulation, examining the location and control of ventilatory pattern generators in the CNS, the influence of chemoreceptor feedback in the form of O 2 and CO 2 /pH fluctuations in the haemolymph, and the role of state-dependent changes in CNS activity on ventilatory control. This information is placed in the context of what is currently known regarding the production of discontinuous gas exchange patterns.

Antibiotic Prescription, Organisms and its Resistance Pattern in Patients Admitted to Respiratory ICU with Respiratory Infection in Mysuru.

PubMed

Mahendra, M; Jayaraj, B S; Lokesh, K S; Chaya, S K; Veerapaneni, Vivek Vardhan; Limaye, Sneha; Dhar, Raja; Swarnakar, Rajesh; Ambalkar, Shrikant; Mahesh, P A

2018-04-01

Respiratory infections account for significant morbidity, mortality and expenses to patients getting admitted to ICU. Antibiotic resistance is a major worldwide concern in ICU, including India. It is important to know the antibiotic prescribing pattern in ICU, organisms and its resistance pattern as there is sparse data on Indian ICUs. We conducted a prospective study from August 2015 to February 2016. All patients getting admitted to RICU with respiratory infection who were treated with antibiotics were included into study. Demographic details, comorbidities, Clinco-pathological score (CPI) on day1 and 2 of admission, duration of ICU admission, number of antibiotics used, antibiotic prescription, antimicrobial resistance pattern of patients were collected using APRISE questionnaire. During study period 352 patients were screened and 303 patients were included into study. Mean age was 56.05±16.37 and 190 (62.70%) were men. Most common diagnosis was Pneumonia (66%). Piperacillin-tazobactam was most common empirical antibiotic used. We found 60% resistance to piperacillin-tazobactam. Acinetobacter baumanii was the most common organism isolated (29.2%) and was highly resistant to Carbapenem (60%). Klebsiella pneumoniae was resistant to Amikacin (45%), piperacillin (55%) and Ceftazidime (50%). Piperacillin-tazobactam was the most common antibiotic prescribed to patients with respiratory infection admitted to ICU. More than half of patients (60%) had resistance to the empirical antibiotic used in our ICU, highlighting the need for antibiogram for each ICU. Thirty six percent of patient had prior antibiotic use and had mainly gram negative organisms with high resistance to commonly used antibiotics.

Assessment of Factors Related to Auto-PEEP.

PubMed

Natalini, Giuseppe; Tuzzo, Daniele; Rosano, Antonio; Testa, Marco; Grazioli, Michele; Pennestrì, Vincenzo; Amodeo, Guido; Marsilia, Paolo F; Tinnirello, Andrea; Berruto, Francesco; Fiorillo, Marialinda; Filippini, Matteo; Peratoner, Alberto; Minelli, Cosetta; Bernardini, Achille

2016-02-01

Previous physiological studies have identified factors that are involved in auto-PEEP generation. In our study, we examined how much auto-PEEP is generated from factors that are involved in its development. One hundred eighty-six subjects undergoing controlled mechanical ventilation with persistent expiratory flow at the beginning of each inspiration were enrolled in the study. Volume-controlled continuous mandatory ventilation with PEEP of 0 cm H2O was applied while maintaining the ventilator setting as chosen by the attending physician. End-expiratory and end-inspiratory airway occlusion maneuvers were performed to calculate respiratory mechanics, and tidal flow limitation was assessed by a maneuver of manual compression of the abdomen. The variable with the strongest effect on auto-PEEP was flow limitation, which was associated with an increase of 2.4 cm H2O in auto-PEEP values. Moreover, auto-PEEP values were directly related to resistance of the respiratory system and body mass index and inversely related to expiratory time/time constant. Variables that were associated with the breathing pattern (tidal volume, frequency minute ventilation, and expiratory time) did not show any relationship with auto-PEEP values. The risk of auto-PEEP ≥5 cm H2O was increased by flow limitation (adjusted odds ratio 17; 95% CI: 6-56.2), expiratory time/time constant ratio <1.85 (12.6; 4.7-39.6), respiratory system resistance >15 cm H2O/L s (3; 1.3-6.9), age >65 y (2.8; 1.2-6.5), and body mass index >26 kg/m(2) (2.6; 1.1-6.1). Flow limitation, expiratory time/time constant, resistance of the respiratory system, and obesity are the most important variables that affect auto-PEEP values. Frequency expiratory time, tidal volume, and minute ventilation were not independently associated with auto-PEEP. Therapeutic strategies aimed at reducing auto-PEEP and its adverse effects should be primarily oriented to the variables that mainly affect auto-PEEP values. Copyright © 2016 by Daedalus Enterprises.

Electrophysiological diagnosis and patterns of response to treatment of botulism with neuromuscular respiratory failure.

PubMed

Kongsaengdao, Subsai; Samintarapanya, Kanoksri; Rusmeechan, Siwarit; Sithinamsuwan, Pasiri; Tanprawate, Surat

2009-08-01

In this study we describe the electrophysiological findings in botulism patients with neuromuscular respiratory failure from major botulism outbreaks in Thailand. High-rate repetitive nerve stimulation testing (RNST) of the abductor digiti minimi (ADM) muscle of 17 botulism patients with neuromuscular respiratory failure showed mostly incremental responses, especially in response to >20-HZ stimulation. In the most severe stage of neuromuscular respiratory failure, RNST failed to elicit a compound muscle action potential (CMAP) of the ADM muscle. In the moderately severe stage, the initial CMAPs were of very low amplitude, and a 3-HZ RNST elicited incremental or decremental responses. A 10-HZ RNST elicited mainly decremental responses. In the early recovery stage, the initial CMAP amplitudes of the ADM muscle improved, with initially low amplitudes and an incremental response to 3- and 10-HZ RNSTs. Improved electrophysiological patterns of the ADM muscle correlated with improved respiratory muscle function. Incremental responses to 20-HZ RNST were most useful for diagnosis. The initial electrodiagnostic sign of recovery following treatment of neuromuscular respiratory failure was an increased CMAP amplitude and an incremental response to 10-20-HZ RNST. Muscle Nerve 40: 271-278, 2009.

Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: A digital phantom study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernatowicz, K., E-mail: kingab@student.ethz.ch; Knopf, A.; Lomax, A.

Purpose: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CTmore » can significantly reduce lung imaging artifacts. Methods: Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) “conventional” 4D CT that uses a constant imaging and couch-shift frequency, (ii) “beam paused” 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) “respiratory-gated” 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm{sup 3} spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Results: Averaged across all simulations and phase bins, respiratory-gating reduced overall thoracic MSE by 46% compared to conventional 4D CT (p ∼ 10{sup −19}). Gating leads to small but significant (p < 0.02) reductions in lung volume errors (1.8%–1.4%), false positives (4.0%–2.6%), and false negatives (2.7%–1.3%). These percentage reductions correspond to gating reducing image artifacts by 24–90 cm{sup 3} of lung tissue. Similar to earlier studies, gating reduced patient image dose by up to 22%, but with scan time increased by up to 135%. Beam paused 4D CT did not significantly impact normal lung tissue image quality, but did yield similar dose reductions as for respiratory-gating, without the added cost in scanning time. Conclusions: For a typical 6 L lung, respiratory-gated 4D CT can reduce image artifacts affecting up to 90 cm{sup 3} of normal lung tissue compared to conventional acquisition. This image improvement could have important implications for dose calculations based on 4D CT. Where image quality is less critical, beam paused 4D CT is a simple strategy to reduce imaging dose without sacrificing acquisition time.« less

SU-F-T-255: Accuracy and Precision of Dynamic Tracking Irradiation with VERO-4DRT System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashi, N; Takada, Y; Mizuno, T

2016-06-15

Purpose: The VERO-4DRT system is able to provide dynamic tracking irradiation (DTI) for the target with respiratory motion. This technique requires enough commissioning for clinical implementation. The purpose of this study is to make sure the accuracy and precision of DTI using VERO- 4DRT through commissioning from fundamental evaluation to end-to-end test. Method: We evaluated several contents for DTI commissioning: the accuracy of absorption dose at isocenter in DTI, the field size and penumbra of DTI, the accuracy of 4D modeling in DTI. All evaluations were performed by respiratory motion phantom (Quasar phantom). These contents were compared the results betweenmore » static irradiation and DTI. The shape of radiation field was set to square from 3 cm × 3 cm to 10 cm × 10 cm. The micro 3D chamber and Gafchromic EBT3 film were used for absorbed dose and relative dose distribution measurement, respectively. The sine and irregular shaped waves were used for demonstrative respiratory motion. The visicoil was implanted into the phantom for guidance of respiratory motion. The respiration patterns of frequency and motion amount were set to 10–15 BPM and 1–2 cm, respectively. Results: As the result of absorbed dose of DTI in comparison with static irradiation, the average dose error at isocenter was 0.5% even though various respiratory patterns were set on. As the result of relative dose distribution, the field size (set it on 50% dose line) was not significantly changed in all respiratory patterns. However, the penumbra was larger in greater respiratory motion (up to 4.1 mm). The 4D modeling coincidence between actual and created waves was within 1%. Conclusion: The DTI using VERO-4DRT can provide sufficient accuracy and precision in absorbed dose and distribution. However, the patientspecific quantitative internal margin corresponding respiratory motion should be taken into consideration with image guidance.« less

Design and development of a micro-thermocouple sensor for determining temperature and relative humidity patterns within an airstream.

PubMed

Eisner, A D; Martonen, T B

1989-11-01

This paper describes the production and calibration of a miniature psychrometer treated with a specially developed porous coating. The investigation was conducted to determine localized patterns of rapidly changing temperature and relative humidity in dynamic flowing gas environments (e.g., with particular attention to future applications to the human respiratory system). The technique involved the use of dry miniature thermocouples and wetted miniature thermocouples coated with boron nitride to act as a wicking material. A precision humidity generator was developed for calibrating the psychrometer. It was found that, in most cases, the measured and expected (i.e., theoretically predicted) relative humidity agreed to within 0.5 to 1.0 percent relative humidity. Procedures that would decrease this discrepancy even further were pinpointed, and advantages of using the miniature psychrometer were assessed.

Changes in the activity of a CpG neuron after the reinforcement of an operantly conditioned behavior in Lymnaea.

PubMed

Spencer, Gaynor E; Kazmi, Mustapha H; Syed, Naweed I; Lukowiak, Ken

2002-10-01

We have previously shown that the aerial respiratory behavior of the mollusk Lymnaea stagnalis can be operantly conditioned, and the central pattern generating (CPG) neurons underlying this behavior have been identified. As neural correlates of operant conditioning remain poorly defined in both vertebrates and invertebrates, we have used the Lymnaea respiratory CPG to investigate neuronal changes associated with the change in behavior after conditioning. After operant conditioning of the intact animals, semi-intact preparations were dissected, so that changes in the respiratory behavior (pneumostome openings) and underlying activity of the identified CPG neuron, right pedal dorsal 1 (RPeD1), could be monitored simultaneously. RPeD1 was studied because it initiates the rhythmic activity of the CPG and receives chemo-sensory input from the pneumostome area. Pneumostome openings and RPeD1 activity were monitored both before and after a reinforcing training stimulus applied to the open pneumostome of operantly conditioned and yoked control preparations. After presentation of the reinforcing stimulus, there was a significant reduction in both breathing behavior and RPeD1 activity in operant preparations but not in yoked and naïve controls. Furthermore these changes were only significant in the subgroup of operantly conditioned animals described as good learners and not in poor learners. These data strongly suggest that changes in RPeD1 activity may underlie the behavioral changes associated with the reinforcement of operant conditioning of the respiratory behavior.

Relationship between dysfunctional breathing patterns and ability to achieve target heart rate variability with features of "coherence" during biofeedback.

PubMed

Courtney, Rosalba; Cohen, Marc; van Dixhoorn, Jan

2011-01-01

Heart rate variability (HRV) biofeedback is a self-regulation strategy used to improve conditions including asthma, stress, hypertension, and chronic obstructive pulmonary disease. Respiratory muscle function affects hemodynamic influences on respiratory sinus arrhythmia (RSA), and HRV and HRV-biofeedback protocols often include slow abdominal breathing to achieve physiologically optimal patterns of HRV with power spectral distribution concentrated around the 0.1-Hz frequency and large amplitude. It is likely that optimal balanced breathing patterns and ability to entrain heart rhythms to breathing reflect physiological efficiency and resilience and that individuals with dysfunctional breathing patterns may have difficulty voluntarily modulating HRV and RSA. The relationship between breathing movement patterns and HRV, however, has not been investigated. This study examines how individuals' habitual breathing patterns correspond with their ability to optimize HRV and RSA. Breathing pattern was assessed using the Manual Assessment of Respiratory Motion (MARM) and the Hi Lo manual palpation techniques in 83 people with possible dysfunctional breathing before they attempted HRV biofeedback. Mean respiratory rate was also assessed. Subsequently, participants applied a brief 5-minute biofeedback protocol, involving breathing and positive emotional focus, to achieve HRV patterns proposed to reflect physiological "coherence" and entrainment of heart rhythm oscillations to other oscillating body systems. Thoracic-dominant breathing was associated with decreased coherence of HRV (r = -.463, P = .0001). Individuals with paradoxical breathing had the lowest HRV coherence (t(8) = 10.7, P = .001), and the negative relationship between coherence of HRV and extent of thoracic breathing was strongest in this group (r = -.768, P = .03). Dysfunctional breathing patterns are associated with decreased ability to achieve HRV patterns that reflect cardiorespiratory efficiency and autonomic nervous system balance. This suggests that dysfunctional breathing patterns are not only biomechanically inefficient but also reflect decreased physiological resilience. Breathing assessment using simple manual techniques such as the MARM and Hi Lo may be useful in HRV biofeedback to identify if poor responders require more emphasis on correction of dysfunctional breathing.

Temporal and Spatial Patterns of Ambient Endotoxin Concentrations in Fresno, California

PubMed Central

Tager, Ira B.; Lurmann, Frederick W.; Haight, Thaddeus; Alcorn, Siana; Penfold, Bryan; Hammond, S. Katharine

2010-01-01

Background Endotoxins are found in indoor dust generated by human activity and pets, in soil, and adsorbed onto the surfaces of ambient combustion particles. Endotoxin concentrations have been associated with respiratory symptoms and the risk of atopy and asthma in children. Objective We characterized the temporal and spatial variability of ambient endotoxin in Fresno/Clovis, California, located in California’s Central Valley, to identify correlates and potential predictors of ambient endotoxin concentrations in a cohort of children with asthma [Fresno Asthmatic Children’s Environment Study (FACES)]. Methods Between May 2001 and October 2004, daily ambient endotoxin and air pollutants were collected at the central ambient monitoring site of the California Air Resources Board in Fresno and, for shorter time periods, at 10 schools and indoors and outdoors at 84 residences in the community. Analyses were restricted to May–October, the dry months during which endotoxin concentrations are highest. Results Daily endotoxin concentration patterns were determined mainly by meteorologic factors, particularly the degree of air stagnation. Overall concentrations were lowest in areas distant from agricultural activities. Highest concentrations were found in areas immediately downwind from agricultural/pasture land. Among three other measured air pollutants [fine particulate matter, elemental carbon (a marker of traffic in Fresno), and coarse particulate matter (PMc)], PMc was the only pollutant correlated with endotoxin. Endotoxin, however, was the most spatially variable. Conclusions Our data support the need to evaluate the spatial/temporal variability of endotoxin concentrations, rather than relying on a few measurements made at one location, in studies of exposure and and respiratory health effects, particularly in children with asthma and other chronic respiratory diseases. PMID:20494854

Synchronization of presynaptic input to motor units of tongue, inspiratory intercostal, and diaphragm muscles.

PubMed

Rice, Amber; Fuglevand, Andrew J; Laine, Christopher M; Fregosi, Ralph F

2011-05-01

The respiratory central pattern generator distributes rhythmic excitatory input to phrenic, intercostal, and hypoglossal premotor neurons. The degree to which this input shapes motor neuron activity can vary across respiratory muscles and motor neuron pools. We evaluated the extent to which respiratory drive synchronizes the activation of motor unit pairs in tongue (genioglossus, hyoglossus) and chest-wall (diaphragm, external intercostals) muscles using coherence analysis. This is a frequency domain technique, which characterizes the frequency and relative strength of neural inputs that are common to each of the recorded motor units. We also examined coherence across the two tongue muscles, as our previous work shows that, despite being antagonists, they are strongly coactivated during the inspiratory phase, suggesting that excitatory input from the premotor neurons is distributed broadly throughout the hypoglossal motoneuron pool. All motor unit pairs showed highly correlated activity in the low-frequency range (1-8 Hz), reflecting the fundamental respiratory frequency and its harmonics. Coherence of motor unit pairs recorded either within or across the tongue muscles was similar, consistent with broadly distributed premotor input to the hypoglossal motoneuron pool. Interestingly, motor units from diaphragm and external intercostal muscles showed significantly higher coherence across the 10-20-Hz bandwidth than tongue-muscle units. We propose that the lower coherence in tongue-muscle motor units over this range reflects a larger constellation of presynaptic inputs, which collectively lead to a reduction in the coherence between hypoglossal motoneurons in this frequency band. This, in turn, may reflect the relative simplicity of the respiratory drive to the diaphragm and intercostal muscles, compared with the greater diversity of functions fulfilled by muscles of the tongue.

Clinical and Molecular Epidemiology of Human Parainfluenza Viruses 1-4 in Children from Viet Nam.

PubMed

Linster, Martin; Do, Lien Anh Ha; Minh, Ngo Ngoc Quang; Chen, Yihui; Zhe, Zhu; Tuan, Tran Anh; Tuan, Ha Manh; Su, Yvonne C F; van Doorn, H Rogier; Moorthy, Mahesh; Smith, Gavin J D

2018-05-01

HPIVs are serologically and genetically grouped into four species that account for up to 10% of all hospitalizations due to acute respiratory infection in children under the age of five. Genetic and epidemiological data for the four HPIVs derived from two pediatric cohorts in Viet Nam are presented. Respiratory samples were screened for HPIV1-4 by real-time PCR. Demographic and clinical data of patients infected with different HPIV were compared. We used a hemi-nested PCR approach to generate viral genome sequences from HPIV-positive samples and conducted a comprehensive phylogenetic analysis. In total, 170 samples tested positive for HPIV. HPIV3 was most commonly detected in our cohort and 80 co-detections of HPIV with other respiratory viruses were found. Phylogenetic analyses suggest local endemic circulation as well as punctuated introductions of new HPIV lineages. Viral gene flow analysis revealed that Viet Nam is a net importer of viral genetic diversity. Epidemiological analyses imply similar disease severity for all HPIV species. HPIV sequences from Viet Nam formed local clusters and were interspersed with sequences from diverse geographic regions. Combined, this new knowledge will help to investigate global HPIV circulation patterns in more detail and ultimately define more suitable vaccine strains.

Respiratory morbidity of pattern and model makers exposed to wood, plastic, and metal products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robins, T.G.; Haboubi, G.; Demers, R.Y.

Pattern and model makers are skilled tradespersons who may be exposed to hardwoods, softwoods, phenol-formaldehyde resin-impregnated woods, epoxy and polyester/styrene resin systems, and welding and metal-casting fumes. The relationship of respiratory symptoms (wheezing, chronic bronchitis, dyspnea) and pulmonary function (FVC% predicted, FEV1% predicted, FEV1/FVC% predicted) with interview-derived cumulative exposure estimates to specific workplace agents and to all work with wood, plastic, or metal products was investigated in 751 pattern and model makers in southeast Michigan. In stratified analyses and age- and smoking-adjusted linear and logistic regression models, measures of cumulative wood exposures were associated with decrements in pulmonary function andmore » dyspnea, but not with other symptoms. In similar analyses, measures of cumulative plastic exposures were associated with wheezing, chronic bronchitis, and dyspnea, but not with decrements in pulmonary function. Prior studies of exposure levels among pattern and model makers and of respiratory health effects of specific agents among other occupational groups support the plausibility of wood-related effects more strongly than that of plastic-related effects.« less

TH-AB-202-07: Radar Tracking of Respiratory Motion in Real Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fung, A; Li, C; Torres, C

Purpose: To propose a method of real time tracking of respiratory motion in patients undergoing radiation therapy. Radar technology can be employed to detection the movement of diaphragm and thoracic anatomy. Methods: A radar transceiver was specially designed. During experiment, the radar device was securely attached to a fixed frame. Respiratory motion was simulated with: 1) Varian RPM phantom, 2) Standard Imaging Respiratory Gating Platform. Signals recorded with radar equipment were compared with those measured with Varian RPM system as a reference. Results: Motion generated by Varian RPM phantom was recorded by the radar device, and compared to the signalsmore » recorded by RPM camera. The results showed exact agreement between the two monitoring equipments. Motion was also generated by Standard Imaging Respiratory Motion Platform. The results showed the radar device was capable of measuring motion of various amplitudes and periods. Conclusion: The proposed radar device is able to measure movements such as respiratory motion. Compared to state-of-the-art respiratory detection instrument, the radar device is shown to be equally precise and effective for monitoring respiration in radiation oncology patients.« less

The etiologic and epidemiologic spectrum of bronchiolitis in pediatric practice.

PubMed

Henderson, F W; Clyde, W A; Collier, A M; Denny, F W; Senior, R J; Sheaffer, C I; Conley, W G; Christian, R M

1979-08-01

To develop a broad understanding of the causes and patterns of occurrence of wheezing associated respiratory infections, we analyzed data from an 11-year study of acute lower respiratory illness in a pediatric practice. Although half of the WARI occurred in children less than 2 years of age, wheezing continued to be observed in 19% of children greater than 9 years of age who had lower respiratory illness. Males experienced LRI 1.25 times more often than did females; the relative risk of males for WARI was 1.35. A nonbacterial pathogen was recovered from 21% of patients with WARI; respiratory syncytial virus, parainfluenza virus types 1 and 3, adenoviruses, and Mycoplasma pneumoniae accounted for 81% of the isolates. Patient age influenced the pattern of recovery of these agents. The most common cause of WARI in children under 5 years of age was RSV whereas Mycoplasma pneumoniae was the most frequent isolate from school age children with wheezing illness. The data expand our understanding of the causes of WARI and are useful to diagnosticians and to researchers interested in the control of lower respiratory disease.

Respiratory muscle function in infants with spinal muscular atrophy type I.

PubMed

Finkel, Richard S; Weiner, Daniel J; Mayer, Oscar H; McDonough, Joseph M; Panitch, Howard B

2014-12-01

To determine the feasibility and safety of respiratory muscle function testing in weak infants with a progressive neuromuscular disorder. Respiratory insufficiency is the major cause of morbidity and mortality in infants with spinal muscular atrophy type I (SMA-I). Tests of respiratory muscle strength, endurance, and breathing patterns can be performed safely in SMA-I infants. Useful data can be collected which parallels the clinical course of pulmonary function in SMA-I. An exploratory study of respiratory muscle function testing and breathing patterns in seven infants with SMA-I seen in our neuromuscular clinic. Measurements were made at initial study visit and, where possible, longitudinally over time. We measured maximal inspiratory (MIP) and transdiaphragmatic pressures, mean transdiaphragmatic pressure, airway occlusion pressure at 100 msec of inspiration, inspiratory and total respiratory cycle time, and aspects of relative thoracoabdominal motion using respiratory inductive plethysmography (RIP). The tension time index of the diaphragm and of the respiratory muscles, phase angle (Φ), phase relation during the total breath, and labored breathing index were calculated. Age at baseline study was 54-237 (median 131) days. Reliable data were obtained safely for MIP, phase angle, labored breathing index, and the invasive and non-invasive tension time indices, even in very weak infants. Data obtained corresponded to the clinical estimate of severity and predicted the need for respiratory support. The testing employed was both safe and feasible. Measurements of MIP and RIP are easily performed tests that are well tolerated and provide clinically useful information for infants with SMA-I. © 2014 Wiley Periodicals, Inc.

Lung function, respiratory symptoms and venous thromboembolism risk: the Atherosclerosis Risk in Communities Study.

PubMed

Kubota, Y; London, S J; Cushman, M; Chamberlain, A M; Rosamond, W D; Heckbert, S R; Zakai, N; Folsom, A R

2016-12-01

Essentials The association of lung function with venous thromboembolism (VTE) is unclear. Chronic obstructive pulmonary disease (COPD) patterns were associated with a higher risk of VTE. Symptoms were also associated with a higher risk of VTE, but a restrictive pattern was not. COPD may increase the risk of VTE and respiratory symptoms may be a novel risk marker for VTE. Background The evidence for the association between chronic obstructive pulmonary disease (COPD) and venous thromboembolism (VTE) is limited. There is no study investigating the association between restrictive lung disease (RLD) and respiratory symptoms with VTE. Objectives To investigate prospectively the association of lung function and respiratory symptoms with VTE. Patients/Methods In 1987-1989, we assessed lung function by using spirometry, and obtained information on respiratory symptoms (cough, phlegm, and dyspnea) in 14 654 participants aged 45-64 years, without a history of VTE or anticoagulant use, and followed them through 2011. Participants were classified into four mutually exclusive groups: 'COPD' (forced expiratory volume in 1 s [FEV 1 ]/forced vital capacity [FVC] below the lower limit of normal [LLN]), 'RLD' (FEV 1 /FVC ≥ LLN and FVC < LLN), 'respiratory symptoms with normal spirometic results' (without RLD or COPD), and 'normal' (without respiratory symptoms, RLD, or COPD). Results We documented 639 VTEs (238 unprovoked and 401 provoked VTEs). After adjustment for VTE risk factors, VTE risk was increased for individuals with either respiratory symptoms with normal spirometric results (hazard ratio [HR] 1.40, 95% confidence interval [CI] 1.12-1.73) or COPD (HR 1.33, 95% CI 1.07-1.67) but not for those with RLD (HR 1.15, 95% CI 0.82-1.60). These elevated risks of VTE were derived from both unprovoked and provoked VTE. Moreover, FEV 1 and FEV 1 /FVC showed dose-response relationships with VTE. COPD was more strongly associated with pulmonary embolism than with deep vein thrombosis. Conclusions Obstructive spirometric patterns were associated with an increased risk of VTE, suggesting that COPD may increase the risk of VTE. Respiratory symptoms may represent a novel risk marker for VTE. © 2016 International Society on Thrombosis and Haemostasis.

Motion robust high resolution 3D free-breathing pulmonary MRI using dynamic 3D image self-navigator.

PubMed

Jiang, Wenwen; Ong, Frank; Johnson, Kevin M; Nagle, Scott K; Hope, Thomas A; Lustig, Michael; Larson, Peder E Z

2018-06-01

To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states. Respiratory motion estimation derived from the proposed dynamic 3D self-navigator of 7.5 mm isotropic reconstruction resolution and a temporal resolution of 300 ms was successful for estimating complex respiratory motion patterns. This estimation improved image quality compared to respiratory belt and DC-based navigators. Respiratory motion compensation with soft-gating and respiratory motion-resolved techniques provided good image quality from highly undersampled data in volunteers and clinical patients. An optimized 3D UTE sequence combined with the proposed reconstruction methods can provide high-resolution motion robust pulmonary MRI. Feasibility was shown in patients who had irregular breathing patterns in which our approach could depict clinically relevant pulmonary pathologies. Magn Reson Med 79:2954-2967, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Ventilatory accommodation of oxygen demand and respiratory water loss in kangaroos from mesic and arid environments, the eastern grey kangaroo (Macropus giganteus) and the red kangaroo (Macropus rufus).

PubMed

Dawson, T J; Munn, A J; Blaney, C E; Krockenberger, A; Maloney, S K

2000-01-01

We studied ventilation in kangaroos from mesic and arid environments, the eastern grey kangaroo (Macropus giganteus) and the red kangaroo (Macropus rufus), respectively, within the range of ambient temperatures (T(a)) from -5 degrees to 45 degrees C. At thermoneutral temperatures (Ta=25 degrees C), there were no differences between the species in respiratory frequency, tidal volume, total ventilation, or oxygen extraction. The ventilatory patterns of the kangaroos were markedly different from those predicted from the allometric equation derived for placentals. The kangaroos had low respiratory frequencies and higher tidal volumes, even when adjustment was made for their lower basal metabolism. At Ta>25 degrees C, ventilation was increased in the kangaroos to facilitate respiratory water loss, with percent oxygen extraction being markedly lowered. Ventilation was via the nares; the mouth was closed. Differences in ventilation between the two species occurred at higher temperatures, and at 45 degrees C were associated with differences in respiratory evaporative heat loss, with that of M. giganteus being higher. Panting in kangaroos occurred as a graded increase in respiratory frequency, during which tidal volume was lowered. When panting, the desert red kangaroo had larger tidal volumes and lower respiratory frequencies at equivalent T(a) than the eastern grey kangaroo, which generally inhabits mesic forests. The inference made from this pattern is that the red kangaroo has the potential to increase respiratory evaporative heat loss to a greater level.

[Effects of transections and electrical coagulations in the medulla oblongata upon the activities in the respiratory muscles of the crucian carp (author's transl)].

PubMed

Fukuda, H

1975-06-01

The following conclusions may be drawn from the results in this work. The respiratory cycles are formed by the neuronal machinery in the reticular formation under the posterior part of the vagal motor nucleus. The motor neurones or the neuronal networks composing the motor nucleus of the respiratory muscles tonically discharge the action potentials, when the neurones or the networks are released from the inhibitory influences of the interneurones connecting the neuronal machinery to the motor neurones. Furthermore, the interneurones probably generate the tonic discharges after removing the inhibitory influences of the other interneurones or the neuronal machinery on them. A reflex mouth closing is elicited by a mechanical stimulus applying on the upper lip. The motor neurones of the m. adductor mandibulae are activated via only one synapse in the reflex. The reflex action potentials recorded from the motor nerve reduce in amplitude at the resting phase of the nerve in the respiratory cycles. These results suggest that the respiratory motor neurones are by nature spontaneous generators of the tonic action potentials and, in the time of the normal breathing, the tonic activity is interrupted by an inhibitory influence of the neuronal machinery generating the respiratory cycles.

Antibiotic Prescription, Organisms and its Resistance Pattern in Patients Admitted to Respiratory ICU with Respiratory Infection in Mysuru

PubMed Central

Mahendra, M; Jayaraj, BS; Lokesh, KS; Chaya, SK; Veerapaneni, Vivek Vardhan; Limaye, Sneha; Dhar, Raja; Swarnakar, Rajesh; Ambalkar, Shrikant; Mahesh, PA

2018-01-01

Aim of Study: Respiratory infections account for significant morbidity, mortality and expenses to patients getting admitted to ICU. Antibiotic resistance is a major worldwide concern in ICU, including India. It is important to know the antibiotic prescribing pattern in ICU, organisms and its resistance pattern as there is sparse data on Indian ICUs. Materials and Methods: We conducted a prospective study from August 2015 to February 2016. All patients getting admitted to RICU with respiratory infection who were treated with antibiotics were included into study. Demographic details, comorbidities, Clinco-pathological score (CPI) on day1 and 2 of admission, duration of ICU admission, number of antibiotics used, antibiotic prescription, antimicrobial resistance pattern of patients were collected using APRISE questionnaire. Results: During study period 352 patients were screened and 303 patients were included into study. Mean age was 56.05±16.37 and 190 (62.70%) were men. Most common diagnosis was Pneumonia (66%). Piperacillin-tazobactam was most common empirical antibiotic used. We found 60% resistance to piperacillin-tazobactam. Acinetobacter baumanii was the most common organism isolated (29.2%) and was highly resistant to Carbapenem (60%). Klebsiella pneumoniae was resistant to Amikacin (45%), piperacillin (55%) and Ceftazidime (50%). Conclusion: Piperacillin-tazobactam was the most common antibiotic prescribed to patients with respiratory infection admitted to ICU. More than half of patients (60%) had resistance to the empirical antibiotic used in our ICU, highlighting the need for antibiogram for each ICU. Thirty six percent of patient had prior antibiotic use and had mainly gram negative organisms with high resistance to commonly used antibiotics. PMID:29743760

Comparison of particle tracking algorithms in commercial CFD packages: sedimentation and diffusion.

PubMed

Robinson, Risa J; Snyder, Pam; Oldham, Michael J

2007-05-01

Computational fluid dynamic modeling software has enabled microdosimetry patterns of inhaled toxins and toxicants to be predicted and visualized, and is being used in inhalation toxicology and risk assessment. These predicted microdosimetry patterns in airway structures are derived from predicted airflow patterns within these airways and particle tracking algorithms used in computational fluid dynamics (CFD) software packages. Although these commercial CFD codes have been tested for accuracy under various conditions, they have not been well tested for respiratory flows in general. Nor has their particle tracking algorithm accuracy been well studied. In this study, three software packages, Fluent Discrete Phase Model (DPM), Fluent Fine Particle Model (FPM), and ANSYS CFX, were evaluated. Sedimentation and diffusion were each isolated in a straight tube geometry and tested for accuracy. A range of flow rates corresponding to adult low activity (minute ventilation = 10 L/min) and to heavy exertion (minute ventilation = 60 L/min) were tested by varying the range of dimensionless diffusion and sedimentation parameters found using the Weibel symmetric 23 generation lung morphology. Numerical results for fully developed parabolic and uniform (slip) profiles were compared respectively, to Pich (1972) and Yu (1977) analytical sedimentation solutions. Schum and Yeh (1980) equations for sedimentation were also compared. Numerical results for diffusional deposition were compared to analytical solutions of Ingham (1975) for parabolic and uniform profiles. Significant differences were found among the various CFD software packages and between numerical and analytical solutions. Therefore, it is prudent to validate CFD predictions against analytical solutions in idealized geometry before tackling the complex geometries of the respiratory tract.

A computational study of the respiratory airflow characteristics in normal and obstructed human airways.

PubMed

Sul, Bora; Wallqvist, Anders; Morris, Michael J; Reifman, Jaques; Rakesh, Vineet

2014-09-01

Obstructive lung diseases in the lower airways are a leading health concern worldwide. To improve our understanding of the pathophysiology of lower airways, we studied airflow characteristics in the lung between the 8th and the 14th generations using a three-dimensional computational fluid dynamics model, where we compared normal and obstructed airways for a range of breathing conditions. We employed a novel technique based on computing the Pearson׳s correlation coefficient to quantitatively characterize the differences in airflow patterns between the normal and obstructed airways. We found that the airflow patterns demonstrated clear differences between normal and diseased conditions for high expiratory flow rates (>2300ml/s), but not for inspiratory flow rates. Moreover, airflow patterns subjected to filtering demonstrated higher sensitivity than airway resistance for differentiating normal and diseased conditions. Further, we showed that wall shear stresses were not only dependent on breathing rates, but also on the distribution of the obstructed sites in the lung: for the same degree of obstruction and breathing rate, we observed as much as two-fold differences in shear stresses. In contrast to previous studies that suggest increased wall shear stress due to obstructions as a possible damage mechanism for small airways, our model demonstrated that for flow rates corresponding to heavy activities, the wall shear stress in both normal and obstructed airways was <0.3Pa, which is within the physiological limit needed to promote respiratory defense mechanisms. In summary, our model enables the study of airflow characteristics that may be impractical to assess experimentally. Published by Elsevier Ltd.

Measurement of Flow Patterns and Dispersion in the Human Airways

NASA Astrophysics Data System (ADS)

Fresconi, Frank E.; Prasad, Ajay K.

2006-03-01

A detailed knowledge of the flow and dispersion within the human respiratory tract is desirable for numerous reasons. Both risk assessments of exposure to toxic particles in the environment and the design of medical delivery systems targeting both lung-specific conditions (asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD)) and system-wide ailments (diabetes, cancer, hormone replacement) would profit from such an understanding. The present work features experimental efforts aimed at elucidating the fluid mechanics of the lung. Particle image velocimetry (PIV) and laser induced fluorescence (LIF) measurements of oscillatory flows were undertaken in anatomically accurate models (single and multi-generational) of the conductive region of the lung. PIV results captured primary and secondary velocity fields. LIF was used to determine the amount of convective dispersion across an individual generation of the lung.

Isolated and synergistic effects of PM10 and average temperature on cardiovascular and respiratory mortality.

PubMed

Pinheiro, Samya de Lara Lins de Araujo; Saldiva, Paulo Hilário Nascimento; Schwartz, Joel; Zanobetti, Antonella

2014-12-01

OBJECTIVE To analyze the effect of air pollution and temperature on mortality due to cardiovascular and respiratory diseases. METHODS We evaluated the isolated and synergistic effects of temperature and particulate matter with aerodynamic diameter < 10 µm (PM10) on the mortality of individuals > 40 years old due to cardiovascular disease and that of individuals > 60 years old due to respiratory diseases in Sao Paulo, SP, Southeastern Brazil, between 1998 and 2008. Three methodologies were used to evaluate the isolated association: time-series analysis using Poisson regression model, bidirectional case-crossover analysis matched by period, and case-crossover analysis matched by the confounding factor, i.e., average temperature or pollutant concentration. The graphical representation of the response surface, generated by the interaction term between these factors added to the Poisson regression model, was interpreted to evaluate the synergistic effect of the risk factors. RESULTS No differences were observed between the results of the case-crossover and time-series analyses. The percentage change in the relative risk of cardiovascular and respiratory mortality was 0.85% (0.45;1.25) and 1.60% (0.74;2.46), respectively, due to an increase of 10 μg/m3 in the PM10 concentration. The pattern of correlation of the temperature with cardiovascular mortality was U-shaped and that with respiratory mortality was J-shaped, indicating an increased relative risk at high temperatures. The values for the interaction term indicated a higher relative risk for cardiovascular and respiratory mortalities at low temperatures and high temperatures, respectively, when the pollution levels reached approximately 60 μg/m3. CONCLUSIONS The positive association standardized in the Poisson regression model for pollutant concentration is not confounded by temperature, and the effect of temperature is not confounded by the pollutant levels in the time-series analysis. The simultaneous exposure to different levels of environmental factors can create synergistic effects that are as disturbing as those caused by extreme concentrations.

Respiratory Tract Lung Geometry and Dosimetry Model for Male Sprague-Dawley Rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Frederick J.; Asgharian, Bahman; Schroeter, Jeffry D.

2015-07-24

While inhalation toxicological studies of various compounds have been conducted using a number of different strains of rats, mechanistic dosimetry models have only had tracheobronchial (TB) structural data for Long-Evans rats, detailed morphometric data on the alveolar region of Sprague-Dawley rats and limited alveolar data on other strains. Based upon CT imaging data for two male Sprague-Dawley rats, a 15-generation, symmetric typical path model was developed for the TB region. Literature data for the alveolar region of Sprague-Dawley rats were analyzed to develop an eight-generation model, and the two regions were joined to provide a complete lower respiratory tract modelmore » for Sprague-Dawley rats. The resulting lung model was used to examine particle deposition in Sprague-Dawley rats and to compare these results with predicted deposition in Long-Evans rats. Relationships of various physiologic variables and lung volumes were either developed in this study or extracted from the literature to provide the necessary input data for examining particle deposition. While the lengths, diameters and branching angles of the TB airways differed between the two Sprague-Dawley rats, the predicted deposition patterns in the three major respiratory tract regions were very similar. Between Sprague-Dawley and Long-Evans rats, significant differences in TB and alveolar predicted deposition fractions were observed over a wide range of particle sizes, with TB deposition fractions being up to 3- to 4-fold greater in Sprague-Dawley rats and alveolar deposition being significantly greater in Long-Evans rats. Thus, strain-specific lung geometry models should be used for particle deposition calculations and interspecies dose comparisons.« less

Respiratory tract lung geometry and dosimetry model for male Sprague-Dawley rats.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Frederick J.; Asgharian, Bahman; Schroeter, Jeffry D.

2014-08-26

While inhalation toxicological studies of various compounds have been conducted using a number of different strains of rats, mechanistic dosimetry models have only had tracheobronchial (TB) structural data for Long-Evans rats, detailed morphometric data on the alveolar region of Sprague-Dawley rats and limited alveolar data on other strains. Based upon CT imaging data for two male Sprague-Dawley rats, a 15-generation, symmetric typical path model was developed for the TB region. Literature data for the alveolar region of Sprague-Dawley rats were analyzed to develop an eight-generation model, and the two regions were joined to provide a complete lower respiratory tract modelmore » for Sprague-Dawley rats. The resulting lung model was used to examine particle deposition in Sprague-Dawley rats and to compare these results with predicted deposition in Long-Evans rats. Relationships of various physiologic variables and lung volumes were either developed in this study or extracted from the literature to provide the necessary input data for examining particle deposition. While the lengths, diameters and branching angles of the TB airways differed between the two Sprague- Dawley rats, the predicted deposition patterns in the three major respiratory tract regions were very similar. Between Sprague-Dawley and Long-Evans rats, significant differences in TB and alveolar predicted deposition fractions were observed over a wide range of particle sizes, with TB deposition fractions being up to 3- to 4-fold greater in Sprague-Dawley rats and alveolar deposition being significantly greater in Long-Evans rats. Thus, strain-specific lung geometry models should be used for particle deposition calculations and interspecies dose comparisons.« less

CFD simulation of aerosol delivery to a human lung via surface acoustic wave nebulization.

PubMed

Yousefi, Morteza; Pourmehran, Oveis; Gorji-Bandpy, Mofid; Inthavong, Kiao; Yeo, Leslie; Tu, Jiyuan

2017-12-01

Administration of drug in the form of particles through inhalation is generally preferable in the treatment of respiratory disorders. Conventional inhalation therapy devices such as inhalers and nebulizers, nevertheless, suffer from low delivery efficiencies, wherein only a small fraction of the inhaled drug reaches the lower respiratory tract. This is primarily because these devices are not able to produce a sufficiently fine drug mist that has aerodynamic diameters on the order of a few microns. This study employs computational fluid dynamics to investigate the transport and deposition of the drug particles produced by a new aerosolization technique driven by surface acoustic waves (SAWs) into an in silico lung model geometrically reconstructed using computed tomography scanning. The particles generated by the SAW are released in different locations in a spacer chamber attached to a lung model extending from the mouth to the 6th generation of the lung bronchial tree. An Eulerian approach is used to solve the Navier-Stokes equations that govern the airflow within the respiratory tract, and a Lagrangian approach is adopted to track the particles, which are assumed to be spherical and inert. Due to the complexity of the lung geometry, the airflow patterns vary as it penetrates deeper into the lung. High inertia particles tend to deposit at locations where the geometry experiences a significant reduction in cross section. Our findings, nevertheless, show that the injection location can influence the delivery efficiency: Injection points close to the spacer centerline result in deeper penetration into the lung. Additionally, we found that the ratio of drug particles entering the right lung is significantly higher than the left lung, independent of the injection location. This is in good agreement with this fact that the most of airflow enters to the right lobes.

SU-F-T-91: Development of Real Time Abdominal Compression Force (ACF) Monitoring System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, T; Kim, D; Kang, S

Purpose: Hard-plate based abdominal compression is known to be effective, but no explicit method exists to quantify abdominal compression force (ACF) and maintain the proper ACF through the whole procedure. In addition, even with compression, it is necessary to do 4D CT to manage residual motion but, 4D CT is often not possible due to reduced surrogating sensitivity. In this study, we developed and evaluated a system that both monitors ACF in real time and provides surrogating signal even under compression. The system can also provide visual-biofeedback. Methods: The system developed consists of a compression plate, an ACF monitoring unitmore » and a visual-biofeedback device. The ACF monitoring unit contains a thin air balloon in the size of compression plate and a gas pressure sensor. The unit is attached to the bottom of the plate thus, placed between the plate and the patient when compression is applied, and detects compression pressure. For reliability test, 3 volunteers were directed to take several different breathing patterns and the ACF variation was compared with the respiratory flow and external respiratory signal to assure that the system provides corresponding behavior. In addition, guiding waveform were generated based on free breathing, and then applied for evaluating the effectiveness of visual-biofeedback. Results: We could monitor ACF variation in real time and confirmed that the data was correlated with both respiratory flow data and external respiratory signal. Even under abdominal compression, in addition, it was possible to make the subjects successfully follow the guide patterns using the visual biofeedback system. Conclusion: The developed real time ACF monitoring system was found to be functional as intended and consistent. With the capability of both providing real time surrogating signal under compression and enabling visual-biofeedback, it is considered that the system would improve the quality of respiratory motion management in radiation therapy. This research was supported by the Mid-career Researcher Program through NRF funded by the Ministry of Science, ICT & Future Planning of Korea (NRF-2014R1A2A1A10050270) and by the Radiation Technology R&D program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (No. 2013M2A2A7038291)« less

Using Mathematical Transmission Modelling to Investigate Drivers of Respiratory Syncytial Virus Seasonality in Children in the Philippines

PubMed Central

Paynter, Stuart; Yakob, Laith; Simões, Eric A. F.; Lucero, Marilla G.; Tallo, Veronica; Nohynek, Hanna; Ware, Robert S.; Weinstein, Philip; Williams, Gail; Sly, Peter D.

2014-01-01

We used a mathematical transmission model to estimate when ecological drivers of respiratory syncytial virus (RSV) transmissibility would need to act in order to produce the observed seasonality of RSV in the Philippines. We estimated that a seasonal peak in transmissibility would need to occur approximately 51 days prior to the observed peak in RSV cases (range 49 to 67 days). We then compared this estimated seasonal pattern of transmissibility to the seasonal patterns of possible ecological drivers of transmissibility: rainfall, humidity and temperature patterns, nutritional status, and school holidays. The timing of the seasonal patterns of nutritional status and rainfall were both consistent with the estimated seasonal pattern of transmissibility and these are both plausible drivers of the seasonality of RSV in this setting. PMID:24587222

Metagenomic analysis of viral diversity in respiratory samples from patients with respiratory tract infections in Kuwait.

PubMed

Madi, Nada; Al-Nakib, Widad; Mustafa, Abu Salim; Habibi, Nazima

2018-03-01

A metagenomic approach based on target independent next-generation sequencing has become a known method for the detection of both known and novel viruses in clinical samples. This study aimed to use the metagenomic sequencing approach to characterize the viral diversity in respiratory samples from patients with respiratory tract infections. We have investigated 86 respiratory samples received from various hospitals in Kuwait between 2015 and 2016 for the diagnosis of respiratory tract infections. A metagenomic approach using the next-generation sequencer to characterize viruses was used. According to the metagenomic analysis, an average of 145, 019 reads were identified, and 2% of these reads were of viral origin. Also, metagenomic analysis of the viral sequences revealed many known respiratory viruses, which were detected in 30.2% of the clinical samples. Also, sequences of non-respiratory viruses were detected in 14% of the clinical samples, while sequences of non-human viruses were detected in 55.8% of the clinical samples. The average genome coverage of the viruses was 12% with the highest genome coverage of 99.2% for respiratory syncytial virus, and the lowest was 1% for torque teno midi virus 2. Our results showed 47.7% agreement between multiplex Real-Time PCR and metagenomics sequencing in the detection of respiratory viruses in the clinical samples. Though there are some difficulties in using this method to clinical samples such as specimen quality, these observations are indicative of the promising utility of the metagenomic sequencing approach for the identification of respiratory viruses in patients with respiratory tract infections. © 2017 Wiley Periodicals, Inc.

Seasonal and pandemic human influenza viruses attach better to human upper respiratory tract epithelium than avian influenza viruses.

PubMed

van Riel, Debby; den Bakker, Michael A; Leijten, Lonneke M E; Chutinimitkul, Salin; Munster, Vincent J; de Wit, Emmie; Rimmelzwaan, Guus F; Fouchier, Ron A M; Osterhaus, Albert D M E; Kuiken, Thijs

2010-04-01

Influenza viruses vary markedly in their efficiency of human-to-human transmission. This variation has been speculated to be determined in part by the tropism of influenza virus for the human upper respiratory tract. To study this tropism, we determined the pattern of virus attachment by virus histochemistry of three human and three avian influenza viruses in human nasal septum, conchae, nasopharynx, paranasal sinuses, and larynx. We found that the human influenza viruses-two seasonal influenza viruses and pandemic H1N1 virus-attached abundantly to ciliated epithelial cells and goblet cells throughout the upper respiratory tract. In contrast, the avian influenza viruses, including the highly pathogenic H5N1 virus, attached only rarely to epithelial cells or goblet cells. Both human and avian viruses attached occasionally to cells of the submucosal glands. The pattern of virus attachment was similar among the different sites of the human upper respiratory tract for each virus tested. We conclude that influenza viruses that are transmitted efficiently among humans attach abundantly to human upper respiratory tract, whereas inefficiently transmitted influenza viruses attach rarely. These results suggest that the ability of an influenza virus to attach to human upper respiratory tract is a critical factor for efficient transmission in the human population.

Inactivity-induced phrenic and hypoglossal motor facilitation are differentially expressed following intermittent vs. sustained neural apnea

PubMed Central

Baertsch, N. A.

2013-01-01

Reduced respiratory neural activity elicits a rebound increase in phrenic and hypoglossal motor output known as inactivity-induced phrenic and hypoglossal motor facilitation (iPMF and iHMF, respectively). We hypothesized that, similar to other forms of respiratory plasticity, iPMF and iHMF are pattern sensitive. Central respiratory neural activity was reversibly reduced in ventilated rats by hyperventilating below the CO2 apneic threshold to create brief intermittent neural apneas (5, ∼1.5 min each, separated by 5 min), a single brief massed neural apnea (7.5 min), or a single prolonged neural apnea (30 min). Upon restoration of respiratory neural activity, long-lasting (>60 min) iPMF was apparent following brief intermittent and prolonged, but not brief massed, neural apnea. Further, brief intermittent and prolonged neural apnea elicited an increase in the maximum phrenic response to high CO2, suggesting that iPMF is associated with an increase in phrenic dynamic range. By contrast, only prolonged neural apnea elicited iHMF, which was transient in duration (<15 min). Intermittent, massed, and prolonged neural apnea all elicited a modest transient facilitation of respiratory frequency. These results indicate that iPMF, but not iHMF, is pattern sensitive, and that the response to respiratory neural inactivity is motor pool specific. PMID:23493368

Stereotypic Laryngeal and Respiratory Motor Patterns Generate Different Call Types in Rat Ultrasound Vocalization

PubMed Central

RIEDE, TOBIAS

2014-01-01

Rodents produce highly variable ultrasound whistles as communication signals unlike many other mammals, who employ flow-induced vocal fold oscillations to produce sound. The role of larynx muscles in controlling sound features across different call types in ultrasound vocalization (USV) was investigated using laryngeal muscle electromyographic (EMG) activity, subglottal pressure measurements and vocal sound output in awake and spontaneously behaving Sprague–Dawley rats. Results support the hypothesis that glottal shape determines fundamental frequency. EMG activities of thyroarytenoid and cricothyroid muscles were aligned with call duration. EMG intensity increased with fundamental frequency. Phasic activities of both muscles were aligned with fast changing fundamental frequency contours, for example in trills. Activities of the sternothyroid and sternohyoid muscles, two muscles involved in vocal production in other mammals, are not critical for the production of rat USV. To test how stereotypic laryngeal and respiratory activity are across call types and individuals, sets of ten EMG and subglottal pressure parameters were measured in six different call types from six rats. Using discriminant function analysis, on average 80% of parameter sets were correctly assigned to their respective call type. This was significantly higher than the chance level. Since fundamental frequency features of USV are tightly associated with stereotypic activity of intrinsic laryngeal muscles and muscles contributing to build-up of subglottal pressure, USV provide insight into the neurophysiological control of peripheral vocal motor patterns. PMID:23423862

Patient training in respiratory-gated radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kini, Vijay R.; Vedam, Subrahmanya S.; Keall, Paul J.

2003-03-31

Respiratory gating is used to counter the effects of organ motion during radiotherapy for chest tumors. The effects of variations in patient breathing patterns during a single treatment and from day to day are unknown. We evaluated the feasibility of using patient training tools and their effect on the breathing cycle regularity and reproducibility during respiratory-gated radiotherapy. To monitor respiratory patterns, we used a component of a commercially available respiratory-gated radiotherapy system (Real Time Position Management (RPM) System, Varian Oncology Systems, Palo Alto, CA 94304). This passive marker video tracking system consists of reflective markers placed on the patient's chestmore » or abdomen, which are detected by a wall-mounted video camera. Software installed on a PC interfaced to this camera detects the marker motion digitally and records it. The marker position as a function of time serves as the motion signal that may be used to trigger imaging or treatment. The training tools used were audio prompting and visual feedback, with free breathing as a control. The audio prompting method used instructions to 'breathe in' or 'breathe out' at periodic intervals deduced from patients' own breathing patterns. In the visual feedback method, patients were shown a real-time trace of their abdominal wall motion due to breathing. Using this, they were asked to maintain a constant amplitude of motion. Motion traces of the abdominal wall were recorded for each patient for various maneuvers. Free breathing showed a variable amplitude and frequency. Audio prompting resulted in a reproducible frequency; however, the variability and the magnitude of amplitude increased. Visual feedback gave a better control over the amplitude but showed minor variations in frequency. We concluded that training improves the reproducibility of amplitude and frequency of patient breathing cycles. This may increase the accuracy of respiratory-gated radiation therapy.« less

Deposition efficiency of inhaled particles (15-5000 nm) related to breathing pattern and lung function: an experimental study in healthy children and adults.

PubMed

Rissler, Jenny; Gudmundsson, Anders; Nicklasson, Hanna; Swietlicki, Erik; Wollmer, Per; Löndahl, Jakob

2017-04-08

Exposure to airborne particles has a major impact on global health. The probability of these particles to deposit in the respiratory tract during breathing is essential for their toxic effects. Observations have shown that there is a substantial variability in deposition between subjects, not only due to respiratory diseases, but also among individuals with healthy lungs. The factors determining this variability are, however, not fully understood. In this study we experimentally investigate factors that determine individual differences in the respiratory tract depositions of inhaled particles for healthy subjects at relaxed breathing. The study covers particles of diameters 15-5000 nm and includes 67 subjects aged 7-70 years. A comprehensive examination of lung function was performed for all subjects. Principal component analyses and multiple regression analyses were used to explore the relationships between subject characteristics and particle deposition. A large individual variability in respiratory tract deposition efficiency was found. Individuals with high deposition of a certain particle size generally had high deposition for all particles <3500 nm. The individual variability was explained by two factors: breathing pattern, and lung structural and functional properties. The most important predictors were found to be breathing frequency and anatomical airway dead space. We also present a linear regression model describing the deposition based on four variables: tidal volume, breathing frequency, anatomical dead space and resistance of the respiratory system (the latter measured with impulse oscillometry). To understand why some individuals are more susceptible to airborne particles we must understand, and take into account, the individual variability in the probability of particles to deposit in the respiratory tract by considering not only breathing patterns but also adequate measures of relevant structural and functional properties.

Generation of a three-dimensional ultrastructural model of human respiratory cilia.

PubMed

Burgoyne, Thomas; Dixon, Mellisa; Luther, Pradeep; Hogg, Claire; Shoemark, Amelia

2012-12-01

The ultrastructures of cilia and flagella are highly similar and well conserved through evolution. Consequently, Chlamydomonas is commonly used as a model organism for the study of human respiratory cilia. Since detailed models of Chlamydomonas axonemes were generated using cryoelectron tomography, disparities among some of the ultrastructural features have become apparent when compared with human cilia. Extrapolating information on human disease from the Chlamydomonas model may lead to discrepancies in translational research. This study aimed to establish the first three-dimensional ultrastructural model of human cilia. Tomograms of transverse sections (n = 6) and longitudinal sections (n = 9) of human nasal respiratory cilia were generated from three healthy volunteers. Key features of the cilium were resolved using subatomic averaging, and were measured. For validation of the method, a model of the well characterized structure of Chlamydomonas reinhardtii was simultaneously generated. Data were combined to create a fully quantified three-dimensional reconstruction of human nasal respiratory cilia. We highlight key differences in the axonemal sheath, microtubular doublets, radial spokes, and dynein arms between the two structures. We show a decreased axial periodicity of the radial spokes, inner dynein arms, and central pair protrusions in the human model. We propose that this first human model will provide a basis for research into the function and structure of human respiratory cilia in health and in disease.

Comparison of Contact Patterns Relevant for Transmission of Respiratory Pathogens in Thailand and the Netherlands Using Respondent-Driven Sampling

PubMed Central

Stein, Mart L.; van Steenbergen, Jim E.; Buskens, Vincent; van der Heijden, Peter G. M.; Chanyasanha, Charnchudhi; Tipayamongkholgul, Mathuros; Thorson, Anna E.; Bengtsson, Linus; Lu, Xin; Kretzschmar, Mirjam E. E.

2014-01-01

Understanding infection dynamics of respiratory diseases requires the identification and quantification of behavioural, social and environmental factors that permit the transmission of these infections between humans. Little empirical information is available about contact patterns within real-world social networks, let alone on differences in these contact networks between populations that differ considerably on a socio-cultural level. Here we compared contact network data that were collected in the Netherlands and Thailand using a similar online respondent-driven method. By asking participants to recruit contact persons we studied network links relevant for the transmission of respiratory infections. We studied correlations between recruiter and recruited contacts to investigate mixing patterns in the observed social network components. In both countries, mixing patterns were assortative by demographic variables and random by total numbers of contacts. However, in Thailand participants reported overall more contacts which resulted in higher effective contact rates. Our findings provide new insights on numbers of contacts and mixing patterns in two different populations. These data could be used to improve parameterisation of mathematical models used to design control strategies. Although the spread of infections through populations depends on more factors, found similarities suggest that spread may be similar in the Netherlands and Thailand. PMID:25423343

FLOW SIMULATION IN THE HUMAN UPPER RESPIRATORY TRACT

EPA Science Inventory

ABSTRACT

Computer simulations of airflow patterns within the human upper respiratory tract (URT) are presented. The URT model includes airways of the head (nasal and oral), throat (pharyngeal and laryngeal), and lungs (trachea and main bronchi). The head and throat mor...

Oscillation patterns are enhanced and firing threshold is lowered in medullary respiratory neuron discharges by threshold doses of a μ-opioid receptor agonist

PubMed Central

Mifflin, Steve W.

2017-01-01

μ-Opioid receptors are distributed widely in the brain stem respiratory network, and opioids with selectivity for μ-type receptors slow in vivo respiratory rhythm in lowest effective doses. Several studies have reported μ-opioid receptor effects on the three-phase rhythm of respiratory neurons, but there are until now no reports of opioid effects on oscillatory activity within respiratory discharges. In this study, effects of the μ-opioid receptor agonist fentanyl on spike train discharge properties of several different types of rhythm-modulating medullary respiratory neuron discharges were analyzed. Doses of fentanyl that were just sufficient for prolongation of discharges and slowing of the three-phase respiratory rhythm also produced pronounced enhancement of spike train properties. Oscillation and burst patterns detected by autocorrelation measurements were greatly enhanced, and interspike intervals were prolonged. Spike train properties under control conditions and after fentanyl were uniform within each experiment, but varied considerably between experiments, which might be related to variability in acid-base balance in the brain stem extracellular fluid. Discharge threshold was shifted to more negative levels of membrane potential. The effects on threshold are postulated to result from opioid-mediated disinhibition and postsynaptic enhancement of N-methyl-d- aspartate receptor current. Lowering of firing threshold, enhancement of spike train oscillations and bursts and prolongation of discharges by lowest effective doses of fentanyl could represent compensatory adjustments in the brain stem respiratory network to override opioid blunting of CO2/pH chemosensitivity. PMID:28202437

Sleep-Disordered Breathing in Children with Rare Skeletal Disorders: A Survey of Clinical Records.

PubMed

Zaffanello, Marco; Piacentini, Giorgio; Sacchetto, Luca; Pietrobelli, Angelo; Gasperi, Emma; Barillari, Marco; Cardobi, Nicolò; Nosetti, Luana; Ramaroli, Diego; Antoniazzi, Franco

2018-06-21

Craniofacial disharmony in skeletal diseases is strongly associated with sleep-disordered breathing. Our aim was to study sleep respiratory patterns in young children with rare skeletal disorders. This retrospective study included children with achondroplasia, osteogenesis imperfecta and Ellis van Creveld Syndrome. Our subjects underwent an in-laboratory overnight respiratory polygraph between January 2012 and April 2016. All medical records were reviewed and brain Magnetic Resonance Imaging was conducted on patients with achondroplasia, nasopharynx, oropharynx and laryngopharynx spaces. 24 children were enrolled, 13 with Achondroplasia, 2 with spondyloepiphyseal dysplasia, 1 with odontochondrodysplasia, 6 with osteogenesis imperfecta and 2 with Ellis van Creveld Syndrome. Children with achondroplasia, who had adenotonsillectomy, showed fewer sleep respiratory involvement than untreated children. Among 13 patients with Achondroplasia, brain magnetic resonance imaging was available in 10 subjects and significant negative correlation was found between sleep respiratory patterns, nasopharynx and oropharynx space (p < 0.05). In 2 patients with spondyloepiphyseal dysplasia, mild to moderate sleep respiratory involvement was found. Both subjects had history of adenotonsillectomy. Mild sleep respiratory involvement was also shown in 4 out of 6 patients with osteogenesis imperfecta. One patient with Ellis van Creveld syndrome had mild sleep respiratory disturbance. Sleep respiratory disturbances were detected in children with achondroplasia, and with less severity also in osteogenesis imperfecta and Ellis van Creveld syndrome. Adenotonsillectomy was successful in achondroplasia in reducing symptoms. In light of our findings, multicenter studies are needed to obtain further information on these rare skeletal diseases. ©2018The Author(s). Published by S. Karger AG, Basel.

Oscillation patterns are enhanced and firing threshold is lowered in medullary respiratory neuron discharges by threshold doses of a μ-opioid receptor agonist.

PubMed

Lalley, Peter M; Mifflin, Steve W

2017-05-01

μ-Opioid receptors are distributed widely in the brain stem respiratory network, and opioids with selectivity for μ-type receptors slow in vivo respiratory rhythm in lowest effective doses. Several studies have reported μ-opioid receptor effects on the three-phase rhythm of respiratory neurons, but there are until now no reports of opioid effects on oscillatory activity within respiratory discharges. In this study, effects of the μ-opioid receptor agonist fentanyl on spike train discharge properties of several different types of rhythm-modulating medullary respiratory neuron discharges were analyzed. Doses of fentanyl that were just sufficient for prolongation of discharges and slowing of the three-phase respiratory rhythm also produced pronounced enhancement of spike train properties. Oscillation and burst patterns detected by autocorrelation measurements were greatly enhanced, and interspike intervals were prolonged. Spike train properties under control conditions and after fentanyl were uniform within each experiment, but varied considerably between experiments, which might be related to variability in acid-base balance in the brain stem extracellular fluid. Discharge threshold was shifted to more negative levels of membrane potential. The effects on threshold are postulated to result from opioid-mediated disinhibition and postsynaptic enhancement of N -methyl-d- aspartate receptor current. Lowering of firing threshold, enhancement of spike train oscillations and bursts and prolongation of discharges by lowest effective doses of fentanyl could represent compensatory adjustments in the brain stem respiratory network to override opioid blunting of CO 2 /pH chemosensitivity. Copyright © 2017 the American Physiological Society.

Optimal ventilatory patterns in periodic breathing.

PubMed

Ghazanshahi, S D; Khoo, M C

1993-01-01

The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

Respiratory Constraints in Verbal and Non-verbal Communication.

PubMed

Włodarczak, Marcin; Heldner, Mattias

2017-01-01

In the present paper we address the old question of respiratory planning in speech production. We recast the problem in terms of speakers' communicative goals and propose that speakers try to minimize respiratory effort in line with the H&H theory. We analyze respiratory cycles coinciding with no speech (i.e., silence), short verbal feedback expressions (SFE's) as well as longer vocalizations in terms of parameters of the respiratory cycle and find little evidence for respiratory planning in feedback production. We also investigate timing of speech and SFEs in the exhalation and contrast it with nods. We find that while speech is strongly tied to the exhalation onset, SFEs are distributed much more uniformly throughout the exhalation and are often produced on residual air. Given that nods, which do not have any respiratory constraints, tend to be more frequent toward the end of an exhalation, we propose a mechanism whereby respiratory patterns are determined by the trade-off between speakers' communicative goals and respiratory constraints.

Biomimetics of fetal alveolar flow phenomena using microfluidics.

PubMed

Tenenbaum-Katan, Janna; Fishler, Rami; Rothen-Rutishauser, Barbara; Sznitman, Josué

2015-01-01

At the onset of life in utero, the respiratory system begins as a liquid-filled tubular organ and undergoes significant morphological changes during fetal development towards establishing a respiratory organ optimized for gas exchange. As airspace morphology evolves, respiratory alveolar flows have been hypothesized to exhibit evolving flow patterns. In the present study, we have investigated flow topologies during increasing phases of embryonic life within an anatomically inspired microfluidic device, reproducing real-scale features of fetal airways representative of three distinct phases of in utero gestation. Micro-particle image velocimetry measurements, supported by computational fluid dynamics simulations, reveal distinct respiratory alveolar flow patterns throughout different stages of fetal life. While attached, streamlined flows characterize the shallow structures of premature alveoli indicative of the onset of saccular stage, separated recirculating vortex flows become the signature of developed and extruded alveoli characteristic of the advanced stages of fetal development. To further mimic physiological aspects of the cellular environment of developing airways, our biomimetic devices integrate an alveolar epithelium using the A549 cell line, recreating a confluent monolayer that produces pulmonary surfactant. Overall, our in vitro biomimetic fetal airways model delivers a robust and reliable platform combining key features of alveolar morphology, flow patterns, and physiological aspects of fetal lungs developing in utero.

Correction of respiratory motion for IMRT using aperture adaptive technique and visual guidance: A feasibility study

NASA Astrophysics Data System (ADS)

Chen, Ho-Hsing; Wu, Jay; Chuang, Keh-Shih; Kuo, Hsiang-Chi

2007-07-01

Intensity-modulated radiation therapy (IMRT) utilizes nonuniform beam profile to deliver precise radiation doses to a tumor while minimizing radiation exposure to surrounding normal tissues. However, the problem of intrafraction organ motion distorts the dose distribution and leads to significant dosimetric errors. In this research, we applied an aperture adaptive technique with a visual guiding system to toggle the problem of respiratory motion. A homemade computer program showing a cyclic moving pattern was projected onto the ceiling to visually help patients adjust their respiratory patterns. Once the respiratory motion becomes regular, the leaf sequence can be synchronized with the target motion. An oscillator was employed to simulate the patient's breathing pattern. Two simple fields and one IMRT field were measured to verify the accuracy. Preliminary results showed that after appropriate training, the amplitude and duration of volunteer's breathing can be well controlled by the visual guiding system. The sharp dose gradient at the edge of the radiation fields was successfully restored. The maximum dosimetric error in the IMRT field was significantly decreased from 63% to 3%. We conclude that the aperture adaptive technique with the visual guiding system can be an inexpensive and feasible alternative without compromising delivery efficiency in clinical practice.

Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens

PubMed Central

Martínez, Isidoro; Oliveros, Juan C.; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Menéndez, Margarita; Moranta, David; Nieto, Amelia; Ortín, Juan; Pérez-González, Alicia; Prat, Cristina; Ramos-Sevillano, Elisa; Regueiro, Verónica; Rodriguez-Frandsen, Ariel; Solís, Dolores; Yuste, José; Bengoechea, José A.; Melero, José A.

2017-01-01

Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here. PMID:28298903

Effect of Rho-kinase inhibition on complexity of breathing pattern in a guinea pig model of asthma

PubMed Central

Pazhoohan, Saeed; Javan, Mohammad; Hajizadeh, Sohrab

2017-01-01

Asthma represents an episodic and fluctuating behavior characterized with decreased complexity of respiratory dynamics. Several evidence indicate that asthma severity or control is associated with alteration in variability of lung function. The pathophysiological basis of alteration in complexity of breathing pattern in asthma has remained poorly understood. Regarding the point that Rho-kinase is involved in pathophysiology of asthma, in present study we investigated the effect of Rho-kinase inhibition on complexity of respiratory dynamics in a guinea pig model of asthma. Male Dunkin Hartley guinea pigs were exposed to 12 series of inhalations with ovalbumin or saline. Animals were treated by the Rho-kinase inhibitor Y-27632 (1mM aerosols) prior to each allergen challenge. We recorded respiration of conscious animals using whole-body plethysmography. Exposure to ovalbumin induced lung inflammation, airway hyperresponsiveness and remodeling including goblet cell hyperplasia, increase in the thickness of airways smooth muscles and subepithelial collagen deposition. Complexity analysis of respiratory dynamics revealed a dramatic decrease in irregularity of respiratory rhythm representing less complexity in asthmatic guinea pigs. Inhibition of Rho-kinase reduced the airway remodeling and hyperreponsiveness, but had no significant effect on lung inflammation and complexity of respiratory dynamics in asthmatic animals. It seems that airway hyperresponsiveness and remodeling do not significantly affect the complexity of respiratory dynamics. Our results suggest that inflammation might be the probable cause of shift in the respiratory dynamics away from the normal fluctuation in asthma. PMID:29088265

Frequency of Respiratory Nursing Diagnoses and Accuracy of Clinical Indicators in Preterm Infants.

PubMed

Avena, Marta José; Pedreira, Mavilde da Luz Gonçalves; Bassolli de Oliveira Alves, Lucas; Herdman, T Heather; de Gutiérrez, Maria Gaby Rivero

2018-03-05

To identify the frequency of the nursing diagnoses, ineffective breathing pattern, impaired gas exchange and impaired spontaneous ventilation in newborns; and, to analyze the accuracy of diagnostic indicators identified for each of these diagnoses. This was a cross-sectional study conducted with a nonprobability sample of 92 infants. Data collected were represented by demographic and clinical variables, clinical indicators of the three respiratory nursing diagnoses from NANDA International, and were analyzed according to frequency and agreement between pairs of expert nurses (Kappa). Ineffective breathing pattern was identified in 74.5% of infants; impaired gas exchange was noted in 31.5%; impaired spontaneous ventilation was found in 16.8% of subjects. Use of accessory muscles to breathe showed the highest sensitivity for ineffective breathing pattern; abnormal blood gases had the best predictive value for impaired gas exchange. Use of accessory muscles to breathe had the highest sensitivity for impaired spontaneous ventilation. Ineffective breathing pattern was the most frequently identified; use of accessory muscles, alteration in depth of breathing, abnormal breathing, and dyspnea were the most representative signs/symptoms. Early recognition of respiratory conditions can support safe interventions to ensure appropriate outcomes. © 2018 NANDA International, Inc.

Early childhood growth patterns and school-age respiratory resistance, fractional exhaled nitric oxide and asthma.

PubMed

Casas, Maribel; den Dekker, Herman T; Kruithof, Claudia J; Reiss, Irwin K; Vrijheid, Martine; de Jongste, Johan C; Jaddoe, Vincent W V; Duijts, Liesbeth

2016-12-01

Greater infant weight gain is associated with lower lung function and increased risk of childhood asthma. The role of early childhood peak growth patterns is unclear. We assessed the associations of individually derived early childhood peak growth patterns with respiratory resistance, fractional exhaled nitric oxide, wheezing patterns, and asthma until school-age. We performed a population-based prospective cohort study among 5364 children. Repeated growth measurements between 0 and 3 years of age were used to derive standard deviation scores (s.d.s) of peak height and weight velocities (PHV and PWV, respectively), and body mass index (BMI) and age at adiposity peak. Respiratory resistance and fractional exhaled nitric oxide were measured at 6 years of age. Wheezing patterns and asthma were prospectively assessed by annual questionnaires. We also assessed whether any association was explained by childhood weight status. Greater PHV was associated with lower respiratory resistance [Z-score (95% CI): -0.03 (-0.04, -0.01) per s.d.s increase] (n = 3382). Greater PWV and BMI at adiposity peak were associated with increased risks of early wheezing [relative risk ratio (95% CI): 1.11 (1.06, 1.16), 1.26 (1.11, 1.43), respectively] and persistent wheezing [relative risk ratio (95% CI): 1.09 (1.03, 1.16), 1.37 (1.17, 1.60), respectively] (n = 3189 and n = 3005, respectively). Childhood weight status partly explained these associations. No other associations were observed. PWV and BMI at adiposity peak are critical for lung developmental and risk of school-age wheezing. Follow-up studies at older ages are needed to elucidate whether these effects persist at later ages. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

THREE-DIMENSIONAL COMPUTATIONAL FLUID DYNAMICS SIMULATIONS OF LOCAL PARTICLE DEPOSITION PATTERNS IN LUNG AIRWAYS

EPA Science Inventory

EPA has identified respirable particulate matter (PM) as a significant threat to human health, particularly in the elderly, in children, and in persons with respiratory disease. However, deposition of PM in the respiratory system is highly variable, depending upon particle chara...

LOWER RESPIRATORY TRACT STRUCTURE OF LABORATORY ANIMALS AND HUMANS: DOSIMETRY IMPLICATIONS

EPA Science Inventory

Significant differences in lower respiratory tract structure exist both within an animal and between species at each level of anatomy. rregular bipodial and tripodial branching patterns of airways are present in human an nonhuman primate lungs. n contrast, the dog and common labo...

Developmental Regulation of Effector and Resident Memory T Cell Generation during Pediatric Viral Respiratory Tract Infection.

PubMed

Connors, Thomas J; Baird, J Scott; Yopes, Margot C; Zens, Kyra D; Pethe, Kalpana; Ravindranath, Thyyar M; Ho, Siu-Hong; Farber, Donna L

2018-05-30

Viral respiratory tract infections (VRTI) remain a leading cause of morbidity and mortality among infants and young children. In mice, optimal protection to VRTI is mediated by recruitment of effector T cells to the lungs and respiratory tract, and subsequent establishment of tissue resident memory T cells (Trm), which provide long-term protection. These critical processes of T cell recruitment to the respiratory tract, their role in disease pathogenesis, and establishment of local protective immunity remain undefined in pediatric VRTI. In this study, we investigated T cell responses in the upper respiratory tract (URT) and lower respiratory tract (LRT) of infants and young children with VRTI, revealing developmental regulation of T cell differentiation and Trm generation in situ. We show a direct concurrence between T cell responses in the URT and LRT, including a preponderance of effector CD8 + T cells that was associated with disease severity. During infant VRTI, there was an accumulation of terminally differentiated effector cells (effector memory RA + T cells) in the URT and LRT with reduced Trm in the early neonatal period, and decreased effector memory RA + T cell and increased Trm formation with age during the early years of childhood. Moreover, human infant T cells exhibit increased expression of the transcription factor T-bet compared with adult T cells, suggesting a mechanism for preferential generation of effector over Trm. The developmental regulation of respiratory T cell responses as revealed in the present study is important for diagnosing, monitoring, and treating VRTI in the critical early life stages. Copyright © 2018 by The American Association of Immunologists, Inc.

A review of the effects of some endocrinological factors on respiratory mechanics.

PubMed

Rubini, Alessandro; Frigo, Alessandro; Carniel, Emanuele Luigi

2016-12-01

Endocrinological factors have been recently described to affect respiratory mechanics. To review recent literature data, most of all obtained by the end-inflation occlusion method, describing the effects of molecules of endocrinological interest such as endothelin, erythropoietin and renin-angiotensin, on respiratory mechanics parameters. The papers considered in this review were found by inserting in Pubmed/Medline the following indexing terms: hormones, endothelin, erythropoietin, angiotensin and respiratory mechanics. It was found that the above cited molecules, beside their well known physiological main effects, exhibit influences on respiratory mechanics, most of all on the airflow resistance, which was described to be increased by endothelin and angiotensin, and decreased by erythropoietin. A number of molecules of biological interest exhibit unexpected influences on respiratory mechanics. The clinical effects depend on the consequences of modified inspiratory pressure values the respiratory muscles have to perform for a given breathing pattern.

Are pacemaker properties required for respiratory rhythm generation in adult turtle brain stems in vitro?

PubMed

Johnson, Stephen M; Wiegel, Liana M; Majewski, David J

2007-08-01

The role of pacemaker properties in vertebrate respiratory rhythm generation is not well understood. To address this question from a comparative perspective, brain stems from adult turtles were isolated in vitro, and respiratory motor bursts were recorded on hypoglossal (XII) nerve rootlets. The goal was to test whether burst frequency could be altered by conditions known to alter respiratory pacemaker neuron activity in mammals (e.g., increased bath KCl or blockade of specific inward currents). While bathed in artificial cerebrospinal fluid (aCSF), respiratory burst frequency was not correlated with changes in bath KCl (0.5-10.0 mM). Riluzole (50 microM; persistent Na(+) channel blocker) increased burst frequency by 31 +/- 5% (P < 0.05) and decreased burst amplitude by 42 +/- 4% (P < 0.05). In contrast, flufenamic acid (FFA, 20-500 microM; Ca(2+)-activated cation channel blocker) reduced and abolished burst frequency in a dose- and time-dependent manner (P < 0.05). During synaptic inhibition blockade with bicuculline (50 microM; GABA(A) channel blocker) and strychnine (50 muM; glycine receptor blocker), rhythmic motor activity persisted, and burst frequency was directly correlated with extracellular KCl (0.5-10.0 mM; P = 0.005). During synaptic inhibition blockade, riluzole (50 microM) did not alter burst frequency, whereas FFA (100 microM) abolished burst frequency (P < 0.05). These data are most consistent with the hypothesis that turtle respiratory rhythm generation requires Ca(2+)-activated cation channels but not pacemaker neurons, which thereby favors the group-pacemaker model. During synaptic inhibition blockade, however, the rhythm generator appears to be transformed into a pacemaker-driven network that requires Ca(2+)-activated cation channels.

Amyloidosis involving the respiratory system: 5-year's experience of a multi-disciplinary group's activity.

PubMed

Scala, Raffaele; Maccari, Uberto; Madioni, Chiara; Venezia, Duccio; La Magra, Lidia Calogera

2015-01-01

Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice.

Cardiorespiratory interactions during resistive load breathing.

PubMed

Calabrese, P; Perrault, H; Dinh, T P; Eberhard, A; Benchetrit, G

2000-12-01

The addition to the respiratory system of a resistive load results in breathing pattern changes and in negative intrathoracic pressure increases. The aim of this study was to use resistive load breathing as a stimulus to the cardiorespiratory interaction and to examine the extent of the changes in heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) in relation to the breathing pattern changes. HRV and RSA were studied in seven healthy subjects where four resistive loads were applied in a random order during the breath and 8-min recording made in each condition. The HRV spectral power components were computed from the R-R interval sequences, and the RSA amplitude and phase were computed from the sinusoid fitting the instantaneous heart rate within each breath. Adding resistive loads resulted in 1) increasing respiratory period, 2) unchanging heart rate, and 3) increasing HRV and changing RSA characteristics. HRV and RSA characteristics are linearly correlated to the respiratory period. These modifications appear to be linked to load-induced changes in the respiratory period in each individual, because HRV and RSA characteristics are similar at a respiratory period obtained either by loading or by imposed frequency breathing. The present results are discussed with regard to the importance of the breathing cycle duration in these cardiorespiratory interactions, suggesting that these interactions may depend on the time necessary for activation and dissipation of neurotransmitters involved in RSA.

Amyloidosis involving the respiratory system: 5-year's experience of a multi-disciplinary group's activity

PubMed Central

Scala, Raffaele; Maccari, Uberto; Madioni, Chiara; Venezia, Duccio; La Magra, Lidia Calogera

2015-01-01

Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice. PMID:26229565

Expression profiles of genes for mitochondrial respiratory energy-dissipating systems and antioxidant enzymes in wheat leaves during de-etiolation.

PubMed

Garmash, Elena V; Velegzhaninov, Ilya O; Grabelnych, Olga I; Borovik, Olga A; Silina, Ekaterina V; Voinikov, Victor K; Golovko, Tamara K

2017-08-01

Mitochondrial respiratory components participate in the maintenance of chloroplast functional activity. This study investigates the effects 48h de-etiolation of spring wheat seedlings (Triticum aestivum L., var. Irgina) on the expression of genes that encode energy-dissipating respiratory components and antioxidant enzymes under continuous light conditions. The expression of AOX1a following the prolonged darkness exhibited a pattern indicating a prominent dependence on light. The expression of other respiratory genes, including NDA2, NDB2, and UCP1b, increased during de-etiolation and dark-to-light transition; however, changes in the expression of these genes occurred later than those in AOX1a expression. A high expression of NDA1 was detected after 12h of de-etiolation. The suppression of AOX1a, NDA2, NDB2, and UCP1b was observed 24h after de-etiolation when the photosynthetic apparatus and its defence systems against excess light were completely developed. The expression patterns of the respiratory genes and several genes encoding antioxidant enzymes (MnSOD, Cu-ZnSOD, t-APX, GR, and GRX) were quite similar. Our data indicate that the induction of nuclear genes encoding respiratory and antioxidant enzymes allow the plants to control reactive oxygen species (ROS) production and avoid oxidative stress during de-etiolation. Copyright © 2017 Elsevier GmbH. All rights reserved.

Rapid prototyping raw models on the basis of high resolution computed tomography lung data for respiratory flow dynamics.

PubMed

Giesel, Frederik L; Mehndiratta, Amit; von Tengg-Kobligk, Hendrik; Schaeffer, A; Teh, Kevin; Hoffman, E A; Kauczor, Hans-Ulrich; van Beek, E J R; Wild, Jim M

2009-04-01

Three-dimensional image reconstruction by volume rendering and rapid prototyping has made it possible to visualize anatomic structures in three dimensions for interventional planning and academic research. Volumetric chest computed tomography was performed on a healthy volunteer. Computed tomographic images of the larger bronchial branches were segmented by an extended three-dimensional region-growing algorithm, converted into a stereolithography file, and used for computer-aided design on a laser sintering machine. The injection of gases for respiratory flow modeling and measurements using magnetic resonance imaging were done on a hollow cast. Manufacturing the rapid prototype took about 40 minutes and included the airway tree from trackea to segmental bronchi (fifth generation). The branching of the airways are clearly visible in the (3)He images, and the radial imaging has the potential to elucidate the airway dimensions. The results for flow patterns in the human bronchial tree using the rapid-prototype model with hyperpolarized helium-3 magnetic resonance imaging show the value of this model for flow phantom studies.

Next Generation Respiratory Viral Vaccine System: Advanced and Emerging Bioengineered Human Lung Epithelia Model (HLEM) Organoid Technology

NASA Technical Reports Server (NTRS)

Goodwin, Thomas J.; Schneider, Sandra L.; MacIntosh, Victor; Gibbons, Thomas F.

2010-01-01

Acute respiratory infections, including pneumonia and influenza, are the S t" leading cause of United States and worldwide deaths. Newly emerging pathogens signaled the need for an advanced generation of vaccine technology.. Human bronchial-tracheal epithelial tissue was bioengineered to detect, identify, host and study the pathogenesis of acute respiratory viral disease. The 3-dimensional (3D) human lung epithelio-mesechymal tissue-like assemblies (HLEM TLAs) share characteristics with human respiratory epithelium: tight junctions, desmosomes, microvilli, functional markers villin, keratins and production of tissue mucin. Respiratory Syntial Virus (RSV) studies demonstrate viral growth kinetics and membrane bound glycoproteins up to day 20 post infection in the human lung-orgainoid infected cell system. Peak replication of RSV occurred on day 10 at 7 log10 particles forming units per ml/day. HLEM is an advanced virus vaccine model and biosentinel system for emergent viral infectious diseases to support DoD global surveillance and military readiness.

Cardiorespiratory Coupling: Common Rhythms in Cardiac, Sympathetic, and Respiratory Activities

PubMed Central

Dick, Thomas E.; Hsieh, Yee-Hsee; Dhingra, Rishi R.; Baekey, David M.; Galán, Roberto F.; Wehrwein, Erica; Morris, Kendall F.

2014-01-01

Cardiorespiratory coupling is an encompassing term describing more than the well-recognized influences of respiration on heart rate and blood pressure. Our data indicate that cardiorespiratory coupling reflects a reciprocal interaction between autonomic and respiratory control systems, and the cardiovascular system modulates the ventilatory pattern as well. For example, cardioventilatory coupling refers to the influence of heart beats and arterial pulse pressure on respiration and is the tendency for the next inspiration to start at a preferred latency after the last heart beat in expiration. Multiple complementary, well-described mechanisms mediate respiration’s influence on cardiovascular function, whereas mechanisms mediating the cardiovascular system’s influence on respiration may only be through the baroreceptors but are just being identified. Our review will describe a differential effect of conditioning rats with either chronic intermittent or sustained hypoxia on sympathetic nerve activity but also on ventilatory pattern variability. Both intermittent and sustained hypoxia increase sympathetic nerve activity after 2 weeks but affect sympatho-respiratory coupling differentially. Intermittent hypoxia enhances sympatho-respiratory coupling, which is associated with low variability in the ventilatory pattern. In contrast, after constant hypobaric hypoxia, 1-to-1 coupling between bursts of sympathetic and phrenic nerve activity is replaced by 2-to-3 coupling. This change in coupling pattern is associated with increased variability of the ventilatory pattern. After baro-denervating hypobaric hypoxic-conditioned rats, splanchnic sympathetic nerve activity becomes tonic (distinct bursts are absent) with decreases during phrenic nerve bursts and ventilatory pattern becomes regular. Thus, conditioning rats to either intermittent or sustained hypoxia accentuates the reciprocal nature of cardiorespiratory coupling. Finally, identifying a compelling physiologic purpose for cardiorespiratory coupling is the biggest barrier for recognizing its significance. Cardiorespiratory coupling has only a small effect on the efficiency of gas exchange; rather, we propose that cardiorespiratory control system may act as weakly coupled oscillator to maintain rhythms within a bounded variability. PMID:24746049

Extracting a respiratory signal from raw dynamic PET data that contain tracer kinetics.

PubMed

Schleyer, P J; Thielemans, K; Marsden, P K

2014-08-07

Data driven gating (DDG) methods provide an alternative to hardware based respiratory gating for PET imaging. Several existing DDG approaches obtain a respiratory signal by observing the change in PET-counts within specific regions of acquired PET data. Currently, these methods do not allow for tracer kinetics which can interfere with the respiratory signal and introduce error. In this work, we produced a DDG method for dynamic PET studies that exhibit tracer kinetics. Our method is based on an existing approach that uses frequency-domain analysis to locate regions within raw PET data that are subject to respiratory motion. In the new approach, an optimised non-stationary short-time Fourier transform was used to create a time-varying 4D map of motion affected regions. Additional processing was required to ensure that the relationship between the sign of the respiratory signal and the physical direction of movement remained consistent for each temporal segment of the 4D map. The change in PET-counts within the 4D map during the PET acquisition was then used to generate a respiratory curve. Using 26 min dynamic cardiac NH3 PET acquisitions which included a hardware derived respiratory measurement, we show that tracer kinetics can severely degrade the respiratory signal generated by the original DDG method. In some cases, the transition of tracer from the liver to the lungs caused the respiratory signal to invert. The new approach successfully compensated for tracer kinetics and improved the correlation between the data-driven and hardware based signals. On average, good correlation was maintained throughout the PET acquisitions.

Estimating respiratory rate from FBG optical sensors by using signal quality measurement.

PubMed

Yongwei Zhu; Maniyeri, Jayachandran; Fook, Victor Foo Siang; Haihong Zhang

2015-08-01

Non-intrusiveness is one of the advantages of in-bed optical sensor device for monitoring vital signs, including heart rate and respiratory rate. Estimating respiratory rate reliably using such sensors, however, is challenging, due to body movement, signal variation according to different subjects or body positions, etc. This paper presents a method for reliable respiratory rate estimation for FBG optical sensors by introducing signal quality estimation. The method estimates the quality of the signal waveform by detecting regularly repetitive patterns using proposed spectrum and cepstrum analysis. Multiple window sizes are used to cater for a wide range of target respiratory rates. Furthermore, the readings of multiple sensors are fused to derive a final respiratory rate. Experiments with 12 subjects and 2 body positions were conducted using polysomnography belt signal as groundtruth. The results demonstrated the effectiveness of the method.

Sleep/wake firing patterns of human genioglossus motor units.

PubMed

Bailey, E Fiona; Fridel, Keith W; Rice, Amber D

2007-12-01

Although studies of the principal tongue protrudor muscle genioglossus (GG) suggest that whole muscle GG electromyographic (EMG) activities are preserved in nonrapid eye movement (NREM) sleep, it is unclear what influence sleep exerts on individual GG motor unit (MU) activities. We characterized the firing patterns of human GG MUs in wakefulness and NREM sleep with the aim of determining 1) whether the range of MU discharge patterns evident in wakefulness is preserved in sleep and 2) what effect the removal of the "wakefulness" input has on the magnitude of the respiratory modulation of MU activities. Microelectrodes inserted into the extrinsic tongue protrudor muscle, the genioglossus, were used to follow the discharge of single MUs. We categorized MU activities on the basis of the temporal relationship between the spike train and the respiration cycle and quantified the magnitude of the respiratory modulation of each MU using the eta (eta(2)) index, in wakefulness and sleep. The majority of MUs exhibited subtle increases or decreases in respiratory modulation but were otherwise unaffected by NREM sleep. In contrast, 30% of MUs exhibited marked sleep-associated changes in discharge frequency and respiratory modulation. We suggest that GG MUs should not be considered exclusively tonic or phasic; rather, the discharge pattern appears to be a flexible feature of GG activities in healthy young adults. Whether such flexibility is important in the response to changes in the chemical and/or mechanical environment and whether it is preserved as a function of aging or in individuals with obstructive sleep apnea are critical questions for future research.

Possible prevalence and transmission of acute respiratory tract infections caused by Streptococcus pneumoniae and Haemophilus influenzae among the internally displaced persons in tsunami disaster evacuation camps of Sri Lanka.

PubMed

Watanabe, Hiroshi; Batuwanthudawe, Ranjith; Thevanesam, Vasanthi; Kaji, Chiharu; Qin, Liang; Nishikiori, Nobuyuki; Saito, Wakana; Saito, Mariko; Watanabe, Kiwao; Oishi, Kazunori; Abeysinghe, Nihal; Kunii, Osamu

2007-01-01

The objective of this prospective study was to investigate the status of acute respiratory tract infections caused by Haemophilus influenzae and Streptococcus pneumoniae in tsunami disaster evacuation camps. Nasopharyngeal swabs (NP) of 324 internally displaced persons (IDP) in 3 different tsunami disaster evacuation camps of Sri Lanka were collected between March 18th and 20th, 2005, and analyzed for MIC, beta-lactamase production, serotypes, PCR and pulsed-field gel electrophoresis (PFGE). Many IDP had respiratory symptoms and the prevalence of cough and/or sputum was 84%, 70.5% and 64.7% in the three camps. Twenty-one H. influenzae from 20 IDP and 25 S. pneumoniae from 22 IDP were isolated from the NP. All H. influenzae isolates were nontypeable, and 5 were beta-lactamase producing. Seventeen pneumococci were susceptible, 5 showed intermediate resistance and 3 were fully resistant to penicillin G. Molecular analysis showed the 21 H. influenzae strains had 13 PFGE patterns and 25 pneumococci had 16 PFGE patterns. All 4 different PFGE patterns of H. influenzae strains were detected in a few IDP in camps 1 and 3, and 5 different PFGE patterns of serotype 3, 22A, 9A, 10A and 11A pneumococci were detected in a few IDP in camps 1 and 3. Our data indicate acute respiratory tract infections caused by various types of H. influenzae and S. pneumoniae appear to have been prevalent, some of which were potentially transmitted from person to person in tsunami disaster evacuation camps.

Cardiorespiratory interactions in patients with atrial flutter.

PubMed

Masè, Michela; Disertori, Marcello; Ravelli, Flavia

2009-01-01

Respiratory sinus arrhythmia (RSA) is generally known as the autonomically mediated modulation of the sinus node pacemaker frequency in synchrony with respiration. Cardiorespiratory interactions have been largely investigated during sinus rhythm, whereas little is known about interactions during reentrant arrhythmias. In this study, cardiorespiratory interactions at the atrial and ventricular level were investigated during atrial flutter (AFL), a supraventricular arrhythmia based on a reentry, by using cross-spectral analysis and computer modeling. The coherence and phase between respiration and atrial (gamma(AA)(2), phi(AA)) and ventricular (gamma(RR)(2), phi(RR)) interval series were estimated in 20 patients with typical AFL (68.0 +/- 8.8 yr) and some degree of atrioventricular (AV) conduction block. In all patients, atrial intervals displayed oscillations strongly coupled and in phase with respiration (gamma(AA)(2)= 0.97 +/- 0.05, phi(AA) = 0.71 +/- 0.31 rad), corresponding to a paradoxical lengthening of intervals during inspiration. The modulation pattern was frequency independent, with in-phase oscillations and short time delays (0.40 +/- 0.15 s) for respiratory frequencies in the range 0.1-0.4 Hz. Ventricular patterns were affected by AV conduction type. In patients with fixed AV conduction, ventricular intervals displayed oscillations strongly coupled (gamma(RR)(2)= 0.97 +/- 0.03) and in phase with respiration (phi(RR) = 1.08 +/- 0.80 rad). Differently, in patients with variable AV conduction, respiratory oscillations were secondary to Wencheback rhythmicity, resulting in a decreased level of coupling (gamma(RR)(2)= 0.50 +/- 0.21). Simulations with a simplified model of AV conduction showed ventricular patterns to originate from the combination of a respiratory modulated atrial input with the functional properties of the AV node. The paradoxical frequency-independent modulation pattern of atrial interval, the short time delays, and the complexity of ventricular rhythm characterize respiratory arrhythmia during AFL and distinguish it from normal RSA. These peculiar features can be explained by assuming a direct mechanical action of respiration on AFL reentrant circuit.

Autonomic nervous system response patterns specificity to basic emotions.

PubMed

Collet, C; Vernet-Maury, E; Delhomme, G; Dittmar, A

1997-01-12

The aim of this study was to test the assumption that the autonomic nervous system responses to emotional stimuli are specific. A series of six slides was randomly presented to the subjects while six autonomic nervous system (ANS) parameters were recorded: skin conductance, skin potential, skin resistance, skin blood flow, skin temperature and instantaneous respiratory frequency. Each slide induced a basic emotion: happiness, surprise, anger, fear, sadness and disgust. Results have been first considered with reference to electrodermal responses (EDR) and secondly through thermo-vascular and respiratory variations. Classical as well as original indices were used to quantify autonomic responses. The six basic emotions were distinguished by Friedman variance analysis. Thus, ANS values corresponding to each emotion were compared two-by-two. EDR distinguished 13 emotion-pairs out of 15. 10 emotion-pairs were separated by skin resistance as well as skin conductance ohmic perturbation duration indices whereas conductance amplitude was only capable of distinguishing 7 emotion-pairs. Skin potential responses distinguished surprise and fear from sadness, and fear from disgust, according to their elementary pattern analysis in form and sign. Two-by-two comparisons of skin temperature, skin blood flow (estimated by the new non-oscillary duration index) and instantaneous respiratory frequency, enabled the distinction of 14 emotion-pairs out of 15. 9 emotion-pairs were distinguished by the non-oscillatory duration index values. Skin temperature was demonstrated to be different i.e. positive versus negative in response to anger and fear. The instantaneous respiratory frequency perturbation duration index was the only one capable of separating sadness from disgust. From the six ANS parameters study, different autonomic patterns were identified, each characterizing one of the six basic emotion used as inducing signals. No index alone, nor group of parameters (EDR and thermovascular for instance) were capable of distinguishing each emotion from another. However, electrodermal, thermo-vascular and respiratory responses taken as a whole, redundantly separated each emotion thus demonstrating the specificity of autonomic patterns.

Effects of mesh style and grid convergence on particle deposition in bifurcating airway models with comparisons to experimental data.

PubMed

Longest, P Worth; Vinchurkar, Samir

2007-04-01

A number of research studies have employed a wide variety of mesh styles and levels of grid convergence to assess velocity fields and particle deposition patterns in models of branching biological systems. Generating structured meshes based on hexahedral elements requires significant time and effort; however, these meshes are often associated with high quality solutions. Unstructured meshes that employ tetrahedral elements can be constructed much faster but may increase levels of numerical diffusion, especially in tubular flow systems with a primary flow direction. The objective of this study is to better establish the effects of mesh generation techniques and grid convergence on velocity fields and particle deposition patterns in bifurcating respiratory models. In order to achieve this objective, four widely used mesh styles including structured hexahedral, unstructured tetrahedral, flow adaptive tetrahedral, and hybrid grids have been considered for two respiratory airway configurations. Initial particle conditions tested are based on the inlet velocity profile or the local inlet mass flow rate. Accuracy of the simulations has been assessed by comparisons to experimental in vitro data available in the literature for the steady-state velocity field in a single bifurcation model as well as the local particle deposition fraction in a double bifurcation model. Quantitative grid convergence was assessed based on a grid convergence index (GCI), which accounts for the degree of grid refinement. The hexahedral mesh was observed to have GCI values that were an order of magnitude below the unstructured tetrahedral mesh values for all resolutions considered. Moreover, the hexahedral mesh style provided GCI values of approximately 1% and reduced run times by a factor of 3. Based on comparisons to empirical data, it was shown that inlet particle seedings should be consistent with the local inlet mass flow rate. Furthermore, the mesh style was found to have an observable effect on cumulative particle depositions with the hexahedral solution most closely matching empirical results. Future studies are needed to assess other mesh generation options including various forms of the hybrid configuration and unstructured hexahedral meshes.

Distinct rhythm generators for inspiration and expiration in the juvenile rat

PubMed Central

Janczewski, Wiktor A; Feldman, Jack L

2006-01-01

Inspiration and active expiration are commonly viewed as antagonistic phases of a unitary oscillator that generates respiratory rhythm. This view conflicts with observations we report here in juvenile rats, where by administration of fentanyl, a selective μ-opiate agonist, and induction of lung reflexes, we separately manipulated the frequency of inspirations and expirations. Moreover, completely transecting the brainstem at the caudal end of the facial nucleus abolished active expirations, while rhythmic inspirations continued. We hypothesize that inspiration and expiration are generated by coupled, anatomically separate rhythm generators, one generating active expiration located close to the facial nucleus in the region of the retrotrapezoid nucleus/parafacial respiratory group, the other generating inspiration located more caudally in the preBötzinger Complex. PMID:16293645

Strength and Cycle Time of Ventilatory Oscillations in Unacclimatized Humans at High Altitude,

DTIC Science & Technology

1983-03-04

that our respiratory monitor- ing techniques were identical. We assume this difference is due to lack of acclimatization in our current subjects. In the...instability in the blood gas feedback con- trol system. Respiratory control system modeling by Khoo et al (8) has shown that such instability is...In a respiratory control sys- tem model a stronger pattern corresponds to increased loop gain at a phase angle of 180 degrees. As shown by Khoo, et

Assessment of breathing patterns and respiratory muscle recruitment during singing and speech in quadriplegia.

PubMed

Tamplin, Jeanette; Brazzale, Danny J; Pretto, Jeffrey J; Ruehland, Warren R; Buttifant, Mary; Brown, Douglas J; Berlowitz, David J

2011-02-01

To explore how respiratory impairment after cervical spinal cord injury affects vocal function, and to explore muscle recruitment strategies used during vocal tasks after quadriplegia. It was hypothesized that to achieve the increased respiratory support required for singing and loud speech, people with quadriplegia use different patterns of muscle recruitment and control strategies compared with control subjects without spinal cord injury. Matched, parallel-group design. Large university-affiliated public hospital. Consenting participants with motor-complete C5-7 quadriplegia (n=6) and able-bodied age-matched controls (n=6) were assessed on physiologic and voice measures during vocal tasks. Not applicable. Standard respiratory function testing, surface electromyographic activity from accessory respiratory muscles, sound pressure levels during vocal tasks, the Voice Handicap Index, and the Perceptual Voice Profile. The group with quadriplegia had a reduced lung capacity (vital capacity, 71% vs 102% of predicted; P=.028), more perceived voice problems (Voice Handicap Index score, 22.5 vs 6.5; P=.046), and greater recruitment of accessory respiratory muscles during both loud and soft volumes (P=.028) than the able-bodied controls. The group with quadriplegia also demonstrated higher accessory muscle activation in changing from soft to loud speech (P=.028). People with quadriplegia have impaired vocal ability and use different muscle recruitment strategies during speech than the able-bodied. These findings will enable us to target specific measurements of respiratory physiology for assessing functional improvements in response to formal therapeutic singing training. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Afferent Neural Feedback Overrides the Modulating Effects of Arousal, Hypercapnia and Hypoxemia on Neonatal Cardio-respiratory Control.

PubMed

Lumb, Kathleen J; Schneider, Jennifer M; Ibrahim, Thowfique; Rigaux, Anita; Hasan, Shabih U

2018-04-20

Evidence at whole animal, organ-system, and cellular and molecular levels suggests that afferent volume feedback is critical for establishment of adequate ventilation at birth. Due to the irreversible nature of vagal ablation studies to date, it was difficult to quantify the roles of afferent volume input, arousal and changes in blood gas tensions on neonatal respiratory control. During reversible perineural vagal block, profound apneas, and hypoxemia and hypercarbia were observed necessitating termination of perineural blockade. Respiratory depression and apneas were independent of the sleep states. We demonstrate that profound apneas and life-threatening respiratory failure in vagally denervated animals do not result from lack of arousal or hypoxemia. Change in sleep state and concomitant respiratory depression result from lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period. Afferent volume feedback plays a vital role in neonatal respiratory control. Mechanisms for the profound respiratory depression and life-threatening apneas observed in vagally denervated neonatal animals remain unclear. We investigated the roles of sleep states, hypoxic-hypercapnia and afferent volume feedback on respiratory depression using reversible perineural vagal block during early postnatal period. Seven lambs were instrumented during the first 48h of life to record/analyze sleep states, diaphragmatic electromyograph, arterial blood gas tensions, systemic arterial blood pressure and rectal temperature. Perineural cuffs were placed around the vagi to attain reversible blockade. Post-operatively, during the awake state, both vagi were blocked using 2% xylocaine for up to 30 minutes. Compared with baseline values, pHa, PaO 2 and SaO 2 decreased and PaCO 2 increased during perineural blockade (P < 0.05). Four of seven animals exhibited apneas of ≥20 sec requiring immediate termination of perineural blockade. Breathing rates decreased from the baseline value of 53 ± 12 to 24 ± 20 breaths/min during blockade despite an increased PaCO 2 (P < 0.001). Following blockade, breathing patterns returned to baseline values despite marked hypocapnia (PaCO 2 33 ± 3 torr; P = 0.03). Respiratory depression and apneas were independent of sleep states. This study provides the much needed physiologic evidence that profound apneas and life-threatening respiratory failure in vagally denervated animals do not result from lack of arousal or hypoxemia. Rather, change in sleep state and concomitant respiratory depression result from lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Numerical study of dynamic glottis and tidal breathing on respiratory sounds in a human upper airway model

PubMed Central

Wang, Zhaoxuan; Talaat, Khaled; Glide-Hurst, Carri; Dong, Haibo

2018-01-01

Background Human snores are caused by vibrating anatomical structures in the upper airway. The glottis is a highly variable structure and a critical organ regulating inhaled flows. However, the effects of the glottis motion on airflow and breathing sound are not well understood, while static glottises have been implemented in most previous in silico studies. The objective of this study is to develop a computational acoustic model of human airways with a dynamic glottis and quantify the effects of glottis motion and tidal breathing on airflow and sound generation. Methods Large eddy simulation and FW-H models were adopted to compute airflows and respiratory sounds in an image-based mouth-lung model. User-defined functions were developed that governed the glottis kinematics. Varying breathing scenarios (static vs. dynamic glottis; constant vs. sinusoidal inhalations) were simulated to understand the effects of glottis motion and inhalation pattern on sound generation. Pressure distributions were measured in airway casts with different glottal openings for model validation purpose. Results Significant flow fluctuations were predicted in the upper airways at peak inhalation rates or during glottal constriction. The inhalation speed through the glottis was the predominating factor in the sound generation while the transient effects were less important. For all frequencies considered (20–2500 Hz), the static glottis substantially underestimated the intensity of the generated sounds, which was most pronounced in the range of 100–500 Hz. Adopting an equivalent steady flow rather than a tidal breathing further underestimated the sound intensity. An increase of 25 dB in average was observed for the life condition (sine-dynamic) compared to the idealized condition (constant-rigid) for the broadband frequencies, with the largest increase of approximately 40 dB at the frequency around 250 Hz. Conclusion Results show that a severely narrowing glottis during inhalation, as well as flow fluctuations in the downstream trachea, can generate audible sound levels. PMID:29101633

Numerical study of dynamic glottis and tidal breathing on respiratory sounds in a human upper airway model.

PubMed

Xi, Jinxiang; Wang, Zhaoxuan; Talaat, Khaled; Glide-Hurst, Carri; Dong, Haibo

2018-05-01

Human snores are caused by vibrating anatomical structures in the upper airway. The glottis is a highly variable structure and a critical organ regulating inhaled flows. However, the effects of the glottis motion on airflow and breathing sound are not well understood, while static glottises have been implemented in most previous in silico studies. The objective of this study is to develop a computational acoustic model of human airways with a dynamic glottis and quantify the effects of glottis motion and tidal breathing on airflow and sound generation. Large eddy simulation and FW-H models were adopted to compute airflows and respiratory sounds in an image-based mouth-lung model. User-defined functions were developed that governed the glottis kinematics. Varying breathing scenarios (static vs. dynamic glottis; constant vs. sinusoidal inhalations) were simulated to understand the effects of glottis motion and inhalation pattern on sound generation. Pressure distributions were measured in airway casts with different glottal openings for model validation purpose. Significant flow fluctuations were predicted in the upper airways at peak inhalation rates or during glottal constriction. The inhalation speed through the glottis was the predominating factor in the sound generation while the transient effects were less important. For all frequencies considered (20-2500 Hz), the static glottis substantially underestimated the intensity of the generated sounds, which was most pronounced in the range of 100-500 Hz. Adopting an equivalent steady flow rather than a tidal breathing further underestimated the sound intensity. An increase of 25 dB in average was observed for the life condition (sine-dynamic) compared to the idealized condition (constant-rigid) for the broadband frequencies, with the largest increase of approximately 40 dB at the frequency around 250 Hz. Results show that a severely narrowing glottis during inhalation, as well as flow fluctuations in the downstream trachea, can generate audible sound levels.

Sleep Related Breathing Disorders in Adults with Down Syndrome.

ERIC Educational Resources Information Center

Resta, Onofrio; Barbaro, Maria Pia Foschino; Giliberti, Tiziana; Caratozzolo, Gennaro; Cagnazzo, Maria Grazia; Scarpelli, Franco; Nocerino, Maria Cristina

2003-01-01

This study evaluated sleep-related breathing disorders in six adults with Down syndrome. Five were found to have respiratory events justifying the diagnosis of sleep apnea syndrome. Results suggest that the nocturnal respiratory pattern of adults with Down syndrome depends on several pathogenetic factors such as age, severity of upper airway…

Climate change, extreme weather events, air pollution and respiratory health in Europe.

PubMed

De Sario, M; Katsouyanni, K; Michelozzi, P

2013-09-01

Due to climate change and other factors, air pollution patterns are changing in several urbanised areas of the world, with a significant effect on respiratory health both independently and synergistically with weather conditions; climate scenarios show Europe as one of the most vulnerable regions. European studies on heatwave episodes have consistently shown a synergistic effect of air pollution and high temperatures, while the potential weather-air pollution interaction during wildfires and dust storms is unknown. Allergen patterns are also changing in response to climate change, and air pollution can modify the allergenic potential of pollens, especially in the presence of specific weather conditions. The underlying mechanisms of all these interactions are not well known; the health consequences vary from decreases in lung function to allergic diseases, new onset of diseases, exacerbation of chronic respiratory diseases, and premature death. These multidimensional climate-pollution-allergen effects need to be taken into account in estimating both climate and air pollution-related respiratory effects, in order to set up adequate policy and public health actions to face both the current and future climate and pollution challenges.

Running and Breathing in Mammals

NASA Astrophysics Data System (ADS)

Bramble, Dennis M.; Carrier, David R.

1983-01-01

Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.

Cumulative lesioning of respiratory interneurons disrupts and precludes motor rhythms in vitro

PubMed Central

Hayes, John A.; Wang, Xueying; Del Negro, Christopher A.

2012-01-01

How brain functions degenerate in the face of progressive cell loss is an important issue that pertains to neurodegenerative diseases and basic properties of neural networks. We developed an automated system that uses two-photon microscopy to detect rhythmic neurons from calcium activity, and then individually laser ablates the targets while monitoring network function in real time. We applied this system to the mammalian respiratory oscillator located in the pre-Bötzinger Complex (preBötC) of the ventral medulla, which spontaneously generates breathing-related motor activity in vitro. Here, we show that cumulatively deleting preBötC neurons progressively decreases respiratory frequency and the amplitude of motor output. On average, the deletion of 120 ± 45 neurons stopped spontaneous respiratory rhythm, and our data suggest ≈82% of the rhythm-generating neurons remain unlesioned. Cumulative ablations in other medullary respiratory regions did not affect frequency but diminished the amplitude of motor output to a lesser degree. These results suggest that the preBötC can sustain insults that destroy no more than ≈18% of its constituent interneurons, which may have implications for the onset of respiratory pathologies in disease states. PMID:22566628

A respiratory alert model for the Shenandoah Valley, Virginia, USA

NASA Astrophysics Data System (ADS)

Hondula, David M.; Davis, Robert E.; Knight, David B.; Sitka, Luke J.; Enfield, Kyle; Gawtry, Stephen B.; Stenger, Phillip J.; Deaton, Michael L.; Normile, Caroline P.; Lee, Temple R.

2013-01-01

Respiratory morbidity (particularly COPD and asthma) can be influenced by short-term weather fluctuations that affect air quality and lung function. We developed a model to evaluate meteorological conditions associated with respiratory hospital admissions in the Shenandoah Valley of Virginia, USA. We generated ensembles of classification trees based on six years of respiratory-related hospital admissions (64,620 cases) and a suite of 83 potential environmental predictor variables. As our goal was to identify short-term weather linkages to high admission periods, the dependent variable was formulated as a binary classification of five-day moving average respiratory admission departures from the seasonal mean value. Accounting for seasonality removed the long-term apparent inverse relationship between temperature and admissions. We generated eight total models specific to the northern and southern portions of the valley for each season. All eight models demonstrate predictive skill (mean odds ratio = 3.635) when evaluated using a randomization procedure. The predictor variables selected by the ensembling algorithm vary across models, and both meteorological and air quality variables are included. In general, the models indicate complex linkages between respiratory health and environmental conditions that may be difficult to identify using more traditional approaches.

Improved attenuation correction for respiratory gated PET/CT with extended-duration cine CT: a simulation study

NASA Astrophysics Data System (ADS)

Zhang, Ruoqiao; Alessio, Adam M.; Pierce, Larry A.; Byrd, Darrin W.; Lee, Tzu-Cheng; De Man, Bruno; Kinahan, Paul E.

2017-03-01

Due to the wide variability of intra-patient respiratory motion patterns, traditional short-duration cine CT used in respiratory gated PET/CT may be insufficient to match the PET scan data, resulting in suboptimal attenuation correction that eventually compromises the PET quantitative accuracy. Thus, extending the duration of cine CT can be beneficial to address this data mismatch issue. In this work, we propose to use a long-duration cine CT for respiratory gated PET/CT, whose cine acquisition time is ten times longer than a traditional short-duration cine CT. We compare the proposed long-duration cine CT with the traditional short-duration cine CT through numerous phantom simulations with 11 respiratory traces measured during patient PET/CT scans. Experimental results show that, the long-duration cine CT reduces the motion mismatch between PET and CT by 41% and improves the overall reconstruction accuracy by 42% on average, as compared to the traditional short-duration cine CT. The long-duration cine CT also reduces artifacts in PET images caused by misalignment and mismatch between adjacent slices in phase-gated CT images. The improvement in motion matching between PET and CT by extending the cine duration depends on the patient, with potentially greater benefits for patients with irregular breathing patterns or larger diaphragm movements.

A new paradigm in respiratory hygiene: modulating respiratory secretions to contain cough bioaerosol without affecting mucus clearance.

PubMed

Zayas, Gustavo; Valle, Juan C; Alonso, Mauricio; Alfaro, Henry; Vega, Daniel; Bonilla, Gloria; Reyes, Miguel; King, Malcolm

2007-08-13

Several strategies and devices have been designed to protect health care providers from acquiring transmissible respiratory diseases while providing care. In modulating the physical characteristics of the respiratory secretions to minimize the aerosolization that facilitates transmission of airborne diseases, a fundamental premise is that the prototype drugs have no adverse effect on the first line of respiratory defense, clearance of mucus by ciliary action. To assess and demonstrate the primary mechanism of our mucomodulators (XLs), we have built our evidence moving from basic laboratory studies to an ex-vivo model and then to an in-vivo large animal model. We exposed anesthetized dogs without hypersecretion to different dose concentrations of aerosolized XL "B", XL "D" and XL "S". We assessed: cardio-respiratory pattern, tracheal mucus clearance, airway patency, and mucus viscoelastic changes. Exposure of frog palate mucus to XLs did not affect the clearance of mucus by ciliary action. Dogs maintained normal cardio-respiratory pattern with XL administration. Tracheal mucociliary clearance in anesthetized dogs indicated a sustained 40% mean increase. Tracheal mucus showed increased filance, and there was no mucus retention in the airways. The ex-vivo frog palate and the in-vivo mammalian models used in this study, appear to be appropriate and complement each other to better assess the effects that our mucomodulators exert on the mucociliary clearance defence mechanism. The physiological function of the mucociliary apparatus was not negatively affected in any of the two epithelial models. Airway mucus crosslinked by mucomodulators is better cleared from an intact airway and normally functioning respiratory system, either due to enhanced interaction with cilia or airflow-dependent mechanisms. Data obtained in this study allow us to assure that we have complied with the fundamental requirement criteria established in the initial phase of developing the concept of mucomodulation: Can we modulate the physical characteristics of the respiratory secretions to reduce aerosolization without affecting normal mucociliary clearance function, or even better improving it?

Superinfection between Influenza and RSV Alternating Patterns in San Luis Potosí State, México

PubMed Central

Velasco-Hernández, Jorge Xicoténcatl; Núñez-López, Mayra; Comas-García, Andreu; Cherpitel, Daniel Ernesto Noyola; Ocampo, Marcos Capistrán

2015-01-01

The objective of this paper is to explain through the ecological hypothesis superinfection and competitive interaction between two viral populations and niche (host) availability, the alternating patterns of Respiratory Syncytial Virus (RSV) and influenza observed in a regional hospital in San Luis Potosí State, México using a mathematical model as a methodological tool. The data analyzed consists of community-based and hospital-based Acute Respiratory Infections (ARI) consultations provided by health-care institutions reported to the State Health Service Epidemiology Department from 2003 through 2009. PMID:25803450

Impact of an annual retreat on process improvement in a respiratory therapy section.

PubMed

Roberts, Vincent T; Kester, Lucy; Stoller, James K

2005-12-01

In order to fulfill the mission of providing superb respiratory care, managing respiratory care services requires communication and collaboration. To enhance communication and collaboration in our Section of Respiratory Therapy at the Cleveland Clinic Foundation, and to generate ideas for improvement, since 1996 we have conducted annual retreats for the Section, during which important challenges and opportunities are discussed in a large-group forum. The current report describes the retreat process and outcomes, namely the ideas generated during these retreats and the frequency with which ideas were implemented successfully. The annual retreat brings together all clinical specialists, supervisors, and managers in the Section of Respiratory Therapy, along with the medical director of Respiratory Therapy and representatives of the staff from each shift. In advance of the annual half-day retreat, supervisors and clinical specialists are asked to write a brief description of things that need improvement and actionable proposed solutions to these challenges. These documents are reviewed by the supervisors, managers, education coordinator, and medical director, and a list of discussion topics for the retreat is formulated. The retreat day begins with a brief introduction and summary of the year's activities and then encourages open-ended discussions regarding the various topics, with the explicit, repeated goal of generating solutions. Minutes are kept to identify specific action items, a list of which is visited repeatedly throughout the year, to assess progress toward successful completion of each action item. In the current analysis, the primary outcome measures are the number of ideas generated as action items during the retreats and the frequency with which these ideas have been implemented. Over the 8 years of annual retreats, 103 action items have been generated, of which 84% (n = 87) have been successfully implemented or completed. As evidence of the importance of this group-based activity, we cite several examples of suggestions and action items that were felt to uniquely represent group process and wisdom and which were not proposed beforehand by individuals. On the basis of this experience, we recommend conducting annual respiratory therapy department retreats. We believe the benefits include collective problem-solving in a public forum to identify solutions not advanced by individuals. Also, we believe that the direct communication in such retreats contributes to enhanced morale, further evidence of which is the very low turnover rate among our respiratory therapists during the 8 years in which we have conducted annual retreats.

Toll-Like Receptor 3 Signaling via TRIF Contributes to a Protective Innate Immune Response to Severe Acute Respiratory Syndrome Coronavirus Infection

PubMed Central

Totura, Allison L.; Whitmore, Alan; Agnihothram, Sudhakar; Schäfer, Alexandra; Katze, Michael G.; Heise, Mark T.

2015-01-01

ABSTRACT Toll-like receptors (TLRs) are sensors that recognize molecular patterns from viruses, bacteria, and fungi to initiate innate immune responses to invading pathogens. The emergence of highly pathogenic coronaviruses severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) is a concern for global public health, as there is a lack of efficacious vaccine platforms and antiviral therapeutic strategies. Previously, it was shown that MyD88, an adaptor protein necessary for signaling by multiple TLRs, is a required component of the innate immune response to mouse-adapted SARS-CoV infection in vivo. Here, we demonstrate that TLR3−/−, TLR4−/−, and TRAM−/− mice are more susceptible to SARS-CoV than wild-type mice but experience only transient weight loss with no mortality in response to infection. In contrast, mice deficient in the TLR3/TLR4 adaptor TRIF are highly susceptible to SARS-CoV infection, showing increased weight loss, mortality, reduced lung function, increased lung pathology, and higher viral titers. Distinct alterations in inflammation were present in TRIF−/− mice infected with SARS-CoV, including excess infiltration of neutrophils and inflammatory cell types that correlate with increased pathology of other known causes of acute respiratory distress syndrome (ARDS), including influenza virus infections. Aberrant proinflammatory cytokine, chemokine, and interferon-stimulated gene (ISG) signaling programs were also noted following infection of TRIF−/− mice that were similar to those seen in human patients with poor disease outcome following SARS-CoV or MERS-CoV infection. These findings highlight the importance of TLR adaptor signaling in generating a balanced protective innate immune response to highly pathogenic coronavirus infections. PMID:26015500

A Wearable Capacitive Sensor for Monitoring Human Respiratory Rate

NASA Astrophysics Data System (ADS)

Kundu, Subrata Kumar; Kumagai, Shinya; Sasaki, Minoru

2013-04-01

Realizing an untethered, low-cost, and comfortably wearable respiratory rate sensor for long-term breathing monitoring application still remains a challenge. In this paper, a conductive-textile-based wearable respiratory rate sensing technique based on the capacitive sensing approach is proposed. The sensing unit consists of two conductive textile electrodes that can be easily fabricated, laminated, and integrated in garments. Respiration cycle is detected by measuring the capacitance of two electrodes placed on the inner anterior and posterior sides of a T-shirt at either the abdomen or chest position. A convenient wearable respiratory sensor setup with a capacitance-to-voltage converter has been devised. Respiratory rate as well as breathing mode can be accurately identified using the designed sensor. The sensor output provides significant information on respiratory flow. The effectiveness of the proposed system for different breathing patterns has been evaluated by experiments.

Chronic respiratory effects of exposure to diesel emissions in coal mines.

PubMed

Ames, R G; Hall, D S; Reger, R B

1984-01-01

A 5-yr prospective design was employed to test the hypothesis that exposure to diesel emissions leads to chronic respiratory effects among underground coal miners. Changes in respiratory function and development of chronic respiratory symptoms were measured during a 5-yr study period (i.e., 1977 to 1982) in 280 diesel-exposed and 838 control miners from Eastern and Western United States underground coal mines. Spirometry measures of respiratory function included forced expiratory volume in 1 sec (FEV1.0), forced vital capacity (FVC), and forced expiratory flow rate at 50% of FVC (FEF50). Chronic respiratory symptom measures, which included chronic cough, chronic phlegm, and breathlessness, were obtained by questionnaires, as were smoking status and occupational history. Based upon these data, the pattern of evidence did not support the hypothesis either in an age-adjusted comparison of diesel vs. nondiesel miners or in an internal analysis by cumulative years of diesel exposure.

Viral Co-Infections in Pediatric Patients Hospitalized with Lower Tract Acute Respiratory Infections.

PubMed

Cebey-López, Miriam; Herberg, Jethro; Pardo-Seco, Jacobo; Gómez-Carballa, Alberto; Martinón-Torres, Nazareth; Salas, Antonio; Martinón-Sánchez, José María; Gormley, Stuart; Sumner, Edward; Fink, Colin; Martinón-Torres, Federico

2015-01-01

Molecular techniques can often reveal a broader range of pathogens in respiratory infections. We aim to investigate the prevalence and age pattern of viral co-infection in children hospitalized with lower tract acute respiratory infection (LT-ARI), using molecular techniques. A nested polymerase chain reaction approach was used to detect Influenza (A, B), metapneumovirus, respiratory syncytial virus (RSV), parainfluenza (1-4), rhinovirus, adenovirus (A-F), bocavirus and coronaviruses (NL63, 229E, OC43) in respiratory samples of children with acute respiratory infection prospectively admitted to any of the GENDRES network hospitals between 2011-2013. The results were corroborated in an independent cohort collected in the UK. A total of 204 and 97 nasopharyngeal samples were collected in the GENDRES and UK cohorts, respectively. In both cohorts, RSV was the most frequent pathogen (52.9% and 36.1% of the cohorts, respectively). Co-infection with multiple viruses was found in 92 samples (45.1%) and 29 samples (29.9%), respectively; this was most frequent in the 12-24 months age group. The most frequently observed co-infection patterns were RSV-Rhinovirus (23 patients, 11.3%, GENDRES cohort) and RSV-bocavirus / bocavirus-influenza (5 patients, 5.2%, UK cohort). The presence of more than one virus in pediatric patients admitted to hospital with LT-ARI is very frequent and seems to peak at 12-24 months of age. The clinical significance of these findings is unclear but should warrant further analysis.

Nutrition in the first 1000 days and respiratory health: A descriptive review of the last five years' literature.

PubMed

Verduci, E; Martelli, A; Miniello, V L; Landi, M; Mariani, B; Brambilla, M; Diaferio, L; Peroni, D G

The aim of this paper is to discuss the current evidence regarding short and long-term health respiratory effects of nutrients and dietary patterns during the first 1000 days from conception. Population of interest included children from birth to two years and their mothers (during pregnancy and lactation). Studies were searched on MEDLINE® and Cochrane database, inserting individually and using the Boolean ANDs and ORs, 'nutrients', 'micronutrients', 'LC-PUFA', 'Mediterranean Diet', 'human milk', 'complementary food', 'pregnancy', 'respiratory disease', 'pulmonary disease', 'asthma', 'epigenetics', 'first 1000 days', 'maternal diet' and 'respiratory health'. All sources were retrieved between 01-09-2015 and 07-12-2016. While unhealthy maternal dietary patterns (high fat intake) during pregnancy can result in alteration of foetal lung development, with increased risk of respiratory disorders, Mediterranean diet has been associated with a lower risk of allergic sensitisation and allergic rhinitis. Breastfeeding has beneficial effects on respiratory infections while evidences about its protective effect on allergic disorders are unclear. During complementary feeding there is no evidence to avoid or encourage exposition to 'highly allergenic' foods to have modification of tolerance development. In children from birth to two years of age, Mediterranean diet has been associated with a lower risk of atopy, wheezing and asthma. Micronutrients, antioxidant and LCPUFA supplementation is not recommended and a whole food approach should be preferred, except for Vitamin D. Copyright © 2017 SEICAP. Published by Elsevier España, S.L.U. All rights reserved.

Viral Co-Infections in Pediatric Patients Hospitalized with Lower Tract Acute Respiratory Infections

PubMed Central

Cebey-López, Miriam; Herberg, Jethro; Pardo-Seco, Jacobo; Gómez-Carballa, Alberto; Martinón-Torres, Nazareth; Salas, Antonio; Martinón-Sánchez, José María; Gormley, Stuart; Sumner, Edward; Fink, Colin; Martinón-Torres, Federico

2015-01-01

Background Molecular techniques can often reveal a broader range of pathogens in respiratory infections. We aim to investigate the prevalence and age pattern of viral co-infection in children hospitalized with lower tract acute respiratory infection (LT-ARI), using molecular techniques. Methods A nested polymerase chain reaction approach was used to detect Influenza (A, B), metapneumovirus, respiratory syncytial virus (RSV), parainfluenza (1–4), rhinovirus, adenovirus (A—F), bocavirus and coronaviruses (NL63, 229E, OC43) in respiratory samples of children with acute respiratory infection prospectively admitted to any of the GENDRES network hospitals between 2011–2013. The results were corroborated in an independent cohort collected in the UK. Results A total of 204 and 97 nasopharyngeal samples were collected in the GENDRES and UK cohorts, respectively. In both cohorts, RSV was the most frequent pathogen (52.9% and 36.1% of the cohorts, respectively). Co-infection with multiple viruses was found in 92 samples (45.1%) and 29 samples (29.9%), respectively; this was most frequent in the 12–24 months age group. The most frequently observed co-infection patterns were RSV—Rhinovirus (23 patients, 11.3%, GENDRES cohort) and RSV—bocavirus / bocavirus—influenza (5 patients, 5.2%, UK cohort). Conclusion The presence of more than one virus in pediatric patients admitted to hospital with LT-ARI is very frequent and seems to peak at 12–24 months of age. The clinical significance of these findings is unclear but should warrant further analysis. PMID:26332375

Functional and histopathological identification of the respiratory failure in a DMSXL transgenic mouse model of myotonic dystrophy

PubMed Central

Panaite, Petrica-Adrian; Kuntzer, Thierry; Gourdon, Geneviève; Lobrinus, Johannes Alexander; Barakat-Walter, Ibtissam

2013-01-01

SUMMARY Acute and chronic respiratory failure is one of the major and potentially life-threatening features in individuals with myotonic dystrophy type 1 (DM1). Despite several clinical demonstrations showing respiratory problems in DM1 patients, the mechanisms are still not completely understood. This study was designed to investigate whether the DMSXL transgenic mouse model for DM1 exhibits respiratory disorders and, if so, to identify the pathological changes underlying these respiratory problems. Using pressure plethysmography, we assessed the breathing function in control mice and DMSXL mice generated after large expansions of the CTG repeat in successive generations of DM1 transgenic mice. Statistical analysis of breathing function measurements revealed a significant decrease in the most relevant respiratory parameters in DMSXL mice, indicating impaired respiratory function. Histological and morphometric analysis showed pathological changes in diaphragmatic muscle of DMSXL mice, characterized by an increase in the percentage of type I muscle fibers, the presence of central nuclei, partial denervation of end-plates (EPs) and a significant reduction in their size, shape complexity and density of acetylcholine receptors, all of which reflect a possible breakdown in communication between the diaphragmatic muscles fibers and the nerve terminals. Diaphragm muscle abnormalities were accompanied by an accumulation of mutant DMPK RNA foci in muscle fiber nuclei. Moreover, in DMSXL mice, the unmyelinated phrenic afferents are significantly lower. Also in these mice, significant neuronopathy was not detected in either cervical phrenic motor neurons or brainstem respiratory neurons. Because EPs are involved in the transmission of action potentials and the unmyelinated phrenic afferents exert a modulating influence on the respiratory drive, the pathological alterations affecting these structures might underlie the respiratory impairment detected in DMSXL mice. Understanding mechanisms of respiratory deficiency should guide pharmaceutical and clinical research towards better therapy for the respiratory deficits associated with DM1. PMID:23180777

Design and performance of a respiratory amplitude gating device for PET/CT imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang Guoping; Chang Tingting; Clark, John W. Jr.

2010-04-15

Purpose: Recently, the authors proposed a free-breathing amplitude gating (FBAG) technique for PET/CT scanners. The implementation of this technique required specialized hardware and software components that were specifically designed to interface with commercial respiratory gating devices to generate the necessary triggers required for the FBAG technique. The objective of this technical note is to introduce an in-house device that integrates all the necessary hardware and software components as well as tracks the patient's respiratory motion to realize amplitude gating on PET/CT scanners. Methods: The in-house device is composed of a piezoelectric transducer coupled to a data-acquisition system in order tomore » monitor the respiratory waveform. A LABVIEW program was designed to control the data-acquisition device and inject triggers into the PET list stream whenever the detected respiratory amplitude crossed a predetermined amplitude range. A timer was also programmed to stop the scan when the accumulated time within the selected amplitude range reached a user-set interval. This device was tested using a volunteer and a phantom study. Results: The results from the volunteer and phantom studies showed that the in-house device can detect similar respiratory signals as commercially available respiratory gating systems and is able to generate the necessary triggers to suppress respiratory motion artifacts. Conclusions: The proposed in-house device can be used to implement the FBAG technique in current PET/CT scanners.« less

Multi-Scale Human Respiratory System Simulations to Study Health Effects of Aging, Disease, and Inhaled Substances

NASA Astrophysics Data System (ADS)

Kunz, Robert; Haworth, Daniel; Dogan, Gulkiz; Kriete, Andres

2006-11-01

Three-dimensional, unsteady simulations of multiphase flow, gas exchange, and particle/aerosol deposition in the human lung are reported. Surface data for human tracheo-bronchial trees are derived from CT scans, and are used to generate three- dimensional CFD meshes for the first several generations of branching. One-dimensional meshes for the remaining generations down to the respiratory units are generated using branching algorithms based on those that have been proposed in the literature, and a zero-dimensional respiratory unit (pulmonary acinus) model is attached at the end of each terminal bronchiole. The process is automated to facilitate rapid model generation. The model is exercised through multiple breathing cycles to compute the spatial and temporal variations in flow, gas exchange, and particle/aerosol deposition. The depth of the 3D/1D transition (at branching generation n) is a key parameter, and can be varied. High-fidelity models (large n) are run on massively parallel distributed-memory clusters, and are used to generate physical insight and to calibrate/validate the 1D and 0D models. Suitably validated lower-order models (small n) can be run on single-processor PC’s with run times that allow model-based clinical intervention for individual patients.

Human respiratory syncytial virus genomic and antigenic variants isolated in two hospitals during one epidemic, in Santiago, Chile.

PubMed

Luchsinger, Vivian; Noy, Andrea Elgueta; Avendaño, Luis F

2008-07-01

Human respiratory syncytial virus (HRSV) is a major cause of severe lower respiratory tract infection (LRI) in children. Distinct variants of the viruses have been described. The objective was to compare the antigenic and genetic variability of HRSV strains recovered from infants admitted to two hospitals during one epidemic in a big city. We analyzed nasopharyngeal aspirates from 201 infants admitted for LRI to two hospitals during 2002 in Santiago, Chile. The analyses were carried out using a panel of monoclonal antibodies against G glycoprotein epitopes (EIA) and RFLP for N and G genes. No differences in HRSV groups A/B and in N patterns distribution were observed among both hospitals. On the contrary, antigenic and genetic G patterns displayed a wide diversity of strains circulating during one epidemic, in one big city. RSV variability assessment depended rather on the tool used for analysis than on the geographical location.

Acute respiratory disease in University of the Philippines and University of Wisconsin students. A comparative study.

PubMed

Evans, A S; D'Allessio, D A; Espiritu-Campos, L; Dick, E C

1967-01-01

In a comparison of acute respiratory disease patterns and incidence in students in a semi-tropical climate at the University of the Philippines with those in students in a temperate climate at the University of Wisconsin, USA, it was found that, while respiratory infections were the commonest cause of infirmary admissions in both institutions, yet, contrary to expectations, their incidence and relative importance were actually greater in the Philippine students than in the Wisconsin students. Peak rates occurred during the rainy season in the Philippines and during the coldest months in Wisconsin. Acute infectious mononucleosis was absent in the Philippines and streptococcal sore throat and primary atypical pneumonia were rare, but the three conditions were common in Wisconsin. The authors suggest that this difference in clinical pattern may be due to immunity in the Philippines students as a result of prior childhood infection.

Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function

PubMed Central

Jiang, Heidi; Zhou, Guangyu; Arora, Nikita; Schuele, Stephan; Rosenow, Joshua; Gottfried, Jay A.

2016-01-01

The need to breathe links the mammalian olfactory system inextricably to the respiratory rhythms that draw air through the nose. In rodents and other small animals, slow oscillations of local field potential activity are driven at the rate of breathing (∼2–12 Hz) in olfactory bulb and cortex, and faster oscillatory bursts are coupled to specific phases of the respiratory cycle. These dynamic rhythms are thought to regulate cortical excitability and coordinate network interactions, helping to shape olfactory coding, memory, and behavior. However, while respiratory oscillations are a ubiquitous hallmark of olfactory system function in animals, direct evidence for such patterns is lacking in humans. In this study, we acquired intracranial EEG data from rare patients (Ps) with medically refractory epilepsy, enabling us to test the hypothesis that cortical oscillatory activity would be entrained to the human respiratory cycle, albeit at the much slower rhythm of ∼0.16–0.33 Hz. Our results reveal that natural breathing synchronizes electrical activity in human piriform (olfactory) cortex, as well as in limbic-related brain areas, including amygdala and hippocampus. Notably, oscillatory power peaked during inspiration and dissipated when breathing was diverted from nose to mouth. Parallel behavioral experiments showed that breathing phase enhances fear discrimination and memory retrieval. Our findings provide a unique framework for understanding the pivotal role of nasal breathing in coordinating neuronal oscillations to support stimulus processing and behavior. SIGNIFICANCE STATEMENT Animal studies have long shown that olfactory oscillatory activity emerges in line with the natural rhythm of breathing, even in the absence of an odor stimulus. Whether the breathing cycle induces cortical oscillations in the human brain is poorly understood. In this study, we collected intracranial EEG data from rare patients with medically intractable epilepsy, and found evidence for respiratory entrainment of local field potential activity in human piriform cortex, amygdala, and hippocampus. These effects diminished when breathing was diverted to the mouth, highlighting the importance of nasal airflow for generating respiratory oscillations. Finally, behavioral data in healthy subjects suggest that breathing phase systematically influences cognitive tasks related to amygdala and hippocampal functions. PMID:27927961

Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function.

PubMed

Zelano, Christina; Jiang, Heidi; Zhou, Guangyu; Arora, Nikita; Schuele, Stephan; Rosenow, Joshua; Gottfried, Jay A

2016-12-07

The need to breathe links the mammalian olfactory system inextricably to the respiratory rhythms that draw air through the nose. In rodents and other small animals, slow oscillations of local field potential activity are driven at the rate of breathing (∼2-12 Hz) in olfactory bulb and cortex, and faster oscillatory bursts are coupled to specific phases of the respiratory cycle. These dynamic rhythms are thought to regulate cortical excitability and coordinate network interactions, helping to shape olfactory coding, memory, and behavior. However, while respiratory oscillations are a ubiquitous hallmark of olfactory system function in animals, direct evidence for such patterns is lacking in humans. In this study, we acquired intracranial EEG data from rare patients (Ps) with medically refractory epilepsy, enabling us to test the hypothesis that cortical oscillatory activity would be entrained to the human respiratory cycle, albeit at the much slower rhythm of ∼0.16-0.33 Hz. Our results reveal that natural breathing synchronizes electrical activity in human piriform (olfactory) cortex, as well as in limbic-related brain areas, including amygdala and hippocampus. Notably, oscillatory power peaked during inspiration and dissipated when breathing was diverted from nose to mouth. Parallel behavioral experiments showed that breathing phase enhances fear discrimination and memory retrieval. Our findings provide a unique framework for understanding the pivotal role of nasal breathing in coordinating neuronal oscillations to support stimulus processing and behavior. Animal studies have long shown that olfactory oscillatory activity emerges in line with the natural rhythm of breathing, even in the absence of an odor stimulus. Whether the breathing cycle induces cortical oscillations in the human brain is poorly understood. In this study, we collected intracranial EEG data from rare patients with medically intractable epilepsy, and found evidence for respiratory entrainment of local field potential activity in human piriform cortex, amygdala, and hippocampus. These effects diminished when breathing was diverted to the mouth, highlighting the importance of nasal airflow for generating respiratory oscillations. Finally, behavioral data in healthy subjects suggest that breathing phase systematically influences cognitive tasks related to amygdala and hippocampal functions. Copyright © 2016 the authors 0270-6474/16/3612448-20$15.00/0.

Imaging and dosimetric errors in 4D PET/CT-guided radiotherapy from patient-specific respiratory patterns: a dynamic motion phantom end-to-end study

NASA Astrophysics Data System (ADS)

Bowen, S. R.; Nyflot, M. J.; Herrmann, C.; Groh, C. M.; Meyer, J.; Wollenweber, S. D.; Stearns, C. W.; Kinahan, P. E.; Sandison, G. A.

2015-05-01

Effective positron emission tomography / computed tomography (PET/CT) guidance in radiotherapy of lung cancer requires estimation and mitigation of errors due to respiratory motion. An end-to-end workflow was developed to measure patient-specific motion-induced uncertainties in imaging, treatment planning, and radiation delivery with respiratory motion phantoms and dosimeters. A custom torso phantom with inserts mimicking normal lung tissue and lung lesion was filled with [18F]FDG. The lung lesion insert was driven by six different patient-specific respiratory patterns or kept stationary. PET/CT images were acquired under motionless ground truth, tidal breathing motion-averaged (3D), and respiratory phase-correlated (4D) conditions. Target volumes were estimated by standardized uptake value (SUV) thresholds that accurately defined the ground-truth lesion volume. Non-uniform dose-painting plans using volumetrically modulated arc therapy were optimized for fixed normal lung and spinal cord objectives and variable PET-based target objectives. Resulting plans were delivered to a cylindrical diode array at rest, in motion on a platform driven by the same respiratory patterns (3D), or motion-compensated by a robotic couch with an infrared camera tracking system (4D). Errors were estimated relative to the static ground truth condition for mean target-to-background (T/Bmean) ratios, target volumes, planned equivalent uniform target doses, and 2%-2 mm gamma delivery passing rates. Relative to motionless ground truth conditions, PET/CT imaging errors were on the order of 10-20%, treatment planning errors were 5-10%, and treatment delivery errors were 5-30% without motion compensation. Errors from residual motion following compensation methods were reduced to 5-10% in PET/CT imaging, <5% in treatment planning, and <2% in treatment delivery. We have demonstrated that estimation of respiratory motion uncertainty and its propagation from PET/CT imaging to RT planning, and RT delivery under a dose painting paradigm is feasible within an integrated respiratory motion phantom workflow. For a limited set of cases, the magnitude of errors was comparable during PET/CT imaging and treatment delivery without motion compensation. Errors were moderately mitigated during PET/CT imaging and significantly mitigated during RT delivery with motion compensation. This dynamic motion phantom end-to-end workflow provides a method for quality assurance of 4D PET/CT-guided radiotherapy, including evaluation of respiratory motion compensation methods during imaging and treatment delivery.

Imaging and dosimetric errors in 4D PET/CT-guided radiotherapy from patient-specific respiratory patterns: a dynamic motion phantom end-to-end study.

PubMed

Bowen, S R; Nyflot, M J; Herrmann, C; Groh, C M; Meyer, J; Wollenweber, S D; Stearns, C W; Kinahan, P E; Sandison, G A

2015-05-07

Effective positron emission tomography / computed tomography (PET/CT) guidance in radiotherapy of lung cancer requires estimation and mitigation of errors due to respiratory motion. An end-to-end workflow was developed to measure patient-specific motion-induced uncertainties in imaging, treatment planning, and radiation delivery with respiratory motion phantoms and dosimeters. A custom torso phantom with inserts mimicking normal lung tissue and lung lesion was filled with [(18)F]FDG. The lung lesion insert was driven by six different patient-specific respiratory patterns or kept stationary. PET/CT images were acquired under motionless ground truth, tidal breathing motion-averaged (3D), and respiratory phase-correlated (4D) conditions. Target volumes were estimated by standardized uptake value (SUV) thresholds that accurately defined the ground-truth lesion volume. Non-uniform dose-painting plans using volumetrically modulated arc therapy were optimized for fixed normal lung and spinal cord objectives and variable PET-based target objectives. Resulting plans were delivered to a cylindrical diode array at rest, in motion on a platform driven by the same respiratory patterns (3D), or motion-compensated by a robotic couch with an infrared camera tracking system (4D). Errors were estimated relative to the static ground truth condition for mean target-to-background (T/Bmean) ratios, target volumes, planned equivalent uniform target doses, and 2%-2 mm gamma delivery passing rates. Relative to motionless ground truth conditions, PET/CT imaging errors were on the order of 10-20%, treatment planning errors were 5-10%, and treatment delivery errors were 5-30% without motion compensation. Errors from residual motion following compensation methods were reduced to 5-10% in PET/CT imaging, <5% in treatment planning, and <2% in treatment delivery. We have demonstrated that estimation of respiratory motion uncertainty and its propagation from PET/CT imaging to RT planning, and RT delivery under a dose painting paradigm is feasible within an integrated respiratory motion phantom workflow. For a limited set of cases, the magnitude of errors was comparable during PET/CT imaging and treatment delivery without motion compensation. Errors were moderately mitigated during PET/CT imaging and significantly mitigated during RT delivery with motion compensation. This dynamic motion phantom end-to-end workflow provides a method for quality assurance of 4D PET/CT-guided radiotherapy, including evaluation of respiratory motion compensation methods during imaging and treatment delivery.

Imaging and dosimetric errors in 4D PET/CT-guided radiotherapy from patient-specific respiratory patterns: a dynamic motion phantom end-to-end study

PubMed Central

Bowen, S R; Nyflot, M J; Hermann, C; Groh, C; Meyer, J; Wollenweber, S D; Stearns, C W; Kinahan, P E; Sandison, G A

2015-01-01

Effective positron emission tomography/computed tomography (PET/CT) guidance in radiotherapy of lung cancer requires estimation and mitigation of errors due to respiratory motion. An end-to-end workflow was developed to measure patient-specific motion-induced uncertainties in imaging, treatment planning, and radiation delivery with respiratory motion phantoms and dosimeters. A custom torso phantom with inserts mimicking normal lung tissue and lung lesion was filled with [18F]FDG. The lung lesion insert was driven by 6 different patient-specific respiratory patterns or kept stationary. PET/CT images were acquired under motionless ground truth, tidal breathing motion-averaged (3D), and respiratory phase-correlated (4D) conditions. Target volumes were estimated by standardized uptake value (SUV) thresholds that accurately defined the ground-truth lesion volume. Non-uniform dose-painting plans using volumetrically modulated arc therapy (VMAT) were optimized for fixed normal lung and spinal cord objectives and variable PET-based target objectives. Resulting plans were delivered to a cylindrical diode array at rest, in motion on a platform driven by the same respiratory patterns (3D), or motion-compensated by a robotic couch with an infrared camera tracking system (4D). Errors were estimated relative to the static ground truth condition for mean target-to-background (T/Bmean) ratios, target volumes, planned equivalent uniform target doses (EUD), and 2%-2mm gamma delivery passing rates. Relative to motionless ground truth conditions, PET/CT imaging errors were on the order of 10–20%, treatment planning errors were 5–10%, and treatment delivery errors were 5–30% without motion compensation. Errors from residual motion following compensation methods were reduced to 5–10% in PET/CT imaging, < 5% in treatment planning, and < 2% in treatment delivery. We have demonstrated that estimation of respiratory motion uncertainty and its propagation from PET/CT imaging to RT planning, and RT delivery under a dose painting paradigm is feasible within an integrated respiratory motion phantom workflow. For a limited set of cases, the magnitude of errors was comparable during PET/CT imaging and treatment delivery without motion compensation. Errors were moderately mitigated during PET/CT imaging and significantly mitigated during RT delivery with motion compensation. This dynamic motion phantom end-to-end workflow provides a method for quality assurance of 4D PET/CT-guided radiotherapy, including evaluation of respiratory motion compensation methods during imaging and treatment delivery. PMID:25884892

Simulation of range imaging-based estimation of respiratory lung motion. Influence of noise, signal dimensionality and sampling patterns.

PubMed

Wilms, M; Werner, R; Blendowski, M; Ortmüller, J; Handels, H

2014-01-01

A major problem associated with the irradiation of thoracic and abdominal tumors is respiratory motion. In clinical practice, motion compensation approaches are frequently steered by low-dimensional breathing signals (e.g., spirometry) and patient-specific correspondence models, which are used to estimate the sought internal motion given a signal measurement. Recently, the use of multidimensional signals derived from range images of the moving skin surface has been proposed to better account for complex motion patterns. In this work, a simulation study is carried out to investigate the motion estimation accuracy of such multidimensional signals and the influence of noise, the signal dimensionality, and different sampling patterns (points, lines, regions). A diffeomorphic correspondence modeling framework is employed to relate multidimensional breathing signals derived from simulated range images to internal motion patterns represented by diffeomorphic non-linear transformations. Furthermore, an automatic approach for the selection of optimal signal combinations/patterns within this framework is presented. This simulation study focuses on lung motion estimation and is based on 28 4D CT data sets. The results show that the use of multidimensional signals instead of one-dimensional signals significantly improves the motion estimation accuracy, which is, however, highly affected by noise. Only small differences exist between different multidimensional sampling patterns (lines and regions). Automatically determined optimal combinations of points and lines do not lead to accuracy improvements compared to results obtained by using all points or lines. Our results show the potential of multidimensional breathing signals derived from range images for the model-based estimation of respiratory motion in radiation therapy.

Assessing Airflow Sensitivity to Healthy and Diseased Lung Conditions in a Computational Fluid Dynamics Model Validated In Vitro.

PubMed

Sul, Bora; Oppito, Zachary; Jayasekera, Shehan; Vanger, Brian; Zeller, Amy; Morris, Michael; Ruppert, Kai; Altes, Talissa; Rakesh, Vineet; Day, Steven; Robinson, Risa; Reifman, Jaques; Wallqvist, Anders

2018-05-01

Computational models are useful for understanding respiratory physiology. Crucial to such models are the boundary conditions specifying the flow conditions at truncated airway branches (terminal flow rates). However, most studies make assumptions about these values, which are difficult to obtain in vivo. We developed a computational fluid dynamics (CFD) model of airflows for steady expiration to investigate how terminal flows affect airflow patterns in respiratory airways. First, we measured in vitro airflow patterns in a physical airway model, using particle image velocimetry (PIV). The measured and computed airflow patterns agreed well, validating our CFD model. Next, we used the lobar flow fractions from a healthy or chronic obstructive pulmonary disease (COPD) subject as constraints to derive different terminal flow rates (i.e., three healthy and one COPD) and computed the corresponding airflow patterns in the same geometry. To assess airflow sensitivity to the boundary conditions, we used the correlation coefficient of the shape similarity (R) and the root-mean-square of the velocity magnitude difference (Drms) between two velocity contours. Airflow patterns in the central airways were similar across healthy conditions (minimum R, 0.80) despite variations in terminal flow rates but markedly different for COPD (minimum R, 0.26; maximum Drms, ten times that of healthy cases). In contrast, those in the upper airway were similar for all cases. Our findings quantify how variability in terminal and lobar flows contributes to airflow patterns in respiratory airways. They highlight the importance of using lobar flow fractions to examine physiologically relevant airflow characteristics.

Productive Infection of Human Embryonic Stem Cell-Derived NKX2.1+ Respiratory Progenitors with Human Rhinovirus.

PubMed

Jenny, Robert A; Hirst, Claire; Lim, Sue Mei; Goulburn, Adam L; Micallef, Suzanne J; Labonne, Tanya; Kicic, Anthony; Ling, Kak-Ming; Stick, Stephen M; Ng, Elizabeth S; Trounson, Alan; Giudice, Antonietta; Elefanty, Andrew G; Stanley, Edouard G

2015-06-01

Airway epithelial cells generated from pluripotent stem cells (PSCs) represent a resource for research into a variety of human respiratory conditions, including those resulting from infection with common human pathogens. Using an NKX2.1-GFP reporter human embryonic stem cell line, we developed a serum-free protocol for the generation of NKX2.1(+) endoderm that, when transplanted into immunodeficient mice, matured into respiratory cell types identified by expression of CC10, MUC5AC, and surfactant proteins. Gene profiling experiments indicated that day 10 NKX2.1(+) endoderm expressed markers indicative of early foregut but lacked genes associated with later stages of respiratory epithelial cell differentiation. Nevertheless, NKX2.1(+) endoderm supported the infection and replication of the common respiratory pathogen human rhinovirus HRV1b. Moreover, NKX2.1(+) endoderm upregulated expression of IL-6, IL-8, and IL-1B in response to infection, a characteristic of human airway epithelial cells. Our experiments provide proof of principle for the use of PSC-derived respiratory epithelial cells in the study of cell-virus interactions. This report provides proof-of-principle experiments demonstrating, for the first time, that human respiratory progenitor cells derived from stem cells in the laboratory can be productively infected with human rhinovirus, the predominant cause of the common cold. ©AlphaMed Press.

Evaluation of bovine coronavirus antibody levels, virus shedding, and respiratory disease incidence throughout the beef cattle production cycle

USDA-ARS?s Scientific Manuscript database

Objective- Determine how levels of serum antibody to bovine coronavirus (BCV) are related to virus shedding patterns and respiratory disease incidence in beef calves at various production stages. Animals- 890 crossbred beef calves from four separately managed herds at the U.S. Meat Animal Research C...

Deposition of Aerosols in the Lung: Physiological Factors

EPA Science Inventory

Ventilation and mechanics of breathing are an integral part of respiratory physiology that directly affect aerosol transport and deposition in the lung. Although natural breathing pattern varies widely among individuals, breathing pattern is controllable, and by using an appropri...

Effectiveness of respiratory-gated radiotherapy with audio-visual biofeedback for synchrotron-based scanned heavy-ion beam delivery

NASA Astrophysics Data System (ADS)

He, Pengbo; Li, Qiang; Zhao, Ting; Liu, Xinguo; Dai, Zhongying; Ma, Yuanyuan

2016-12-01

A synchrotron-based heavy-ion accelerator operates in pulse mode at a low repetition rate that is comparable to a patient’s breathing rate. To overcome inefficiencies and interplay effects between the residual motion of the target and the scanned heavy-ion beam delivery process for conventional free breathing (FB)-based gating therapy, a novel respiratory guidance method was developed to help patients synchronize their breathing patterns with the synchrotron excitation patterns by performing short breath holds with the aid of personalized audio-visual biofeedback (BFB) system. The purpose of this study was to evaluate the treatment precision, efficiency and reproducibility of the respiratory guidance method in scanned heavy-ion beam delivery mode. Using 96 breathing traces from eight healthy volunteers who were asked to breathe freely and guided to perform short breath holds with the aid of BFB, a series of dedicated four-dimensional dose calculations (4DDC) were performed on a geometric model which was developed assuming a linear relationship between external surrogate and internal tumor motions. The outcome of the 4DDCs was quantified in terms of the treatment time, dose-volume histograms (DVH) and dose homogeneity index. Our results show that with the respiratory guidance method the treatment efficiency increased by a factor of 2.23-3.94 compared with FB gating, depending on the duty cycle settings. The magnitude of dose inhomogeneity for the respiratory guidance methods was 7.5 times less than that of the non-gated irradiation, and good reproducibility of breathing guidance among different fractions was achieved. Thus, our study indicates that the respiratory guidance method not only improved the overall treatment efficiency of respiratory-gated scanned heavy-ion beam delivery, but also had the advantages of lower dose uncertainty and better reproducibility among fractions.

A multivariate time-frequency method to characterize the influence of respiration over heart period and arterial pressure

NASA Astrophysics Data System (ADS)

Orini, Michele; Bailón, Raquel; Laguna, Pablo; Mainardi, Luca T.; Barbieri, Riccardo

2012-12-01

Respiratory activity introduces oscillations both in arterial pressure and heart period, through mechanical and autonomic mechanisms. Respiration, arterial pressure, and heart period are, generally, non-stationary processes and the interactions between them are dynamic. In this study we present a methodology to robustly estimate the time course of cross spectral indices to characterize dynamic interactions between respiratory oscillations of heart period and blood pressure, as well as their interactions with respiratory activity. Time-frequency distributions belonging to Cohen's class are used to estimate time-frequency (TF) representations of coherence, partial coherence and phase difference. The characterization is based on the estimation of the time course of cross spectral indices estimated in specific TF regions around the respiratory frequency. We used this methodology to describe the interactions between respiration, heart period variability (HPV) and systolic arterial pressure variability (SAPV) during tilt table test with both spontaneous and controlled respiratory patterns. The effect of selective autonomic blockade was also studied. Results suggest the presence of common underling mechanisms of regulation between cardiovascular signals, whose interactions are time-varying. SAPV changes followed respiratory flow both in supine and standing positions and even after selective autonomic blockade. During head-up tilt, phase differences between respiration and SAPV increased. Phase differences between respiration and HPV were comparable to those between respiration and SAPV during supine position, and significantly increased during standing. As a result, respiratory oscillations in SAPV preceded respiratory oscillations in HPV during standing. Partial coherence was the most sensitive index to orthostatic stress. Phase difference estimates were consistent among spontaneous and controlled breathing patterns, whereas coherence was higher in spontaneous breathing. Parasympathetic blockade did not affect interactions between respiration and SAPV, reduced the coherence between SAPV and HPV and between respiration and HPV. Our results support the hypothesis that non-autonomic, possibly mechanically mediated, mechanisms also contributes to the respiratory oscillations in HPV. A small contribution of sympathetic activity on HPV-SAPV interactions around the respiratory frequency was also observed.

Auscultation of the respiratory system

PubMed Central

Sarkar, Malay; Madabhavi, Irappa; Niranjan, Narasimhalu; Dogra, Megha

2015-01-01

Auscultation of the lung is an important part of the respiratory examination and is helpful in diagnosing various respiratory disorders. Auscultation assesses airflow through the trachea-bronchial tree. It is important to distinguish normal respiratory sounds from abnormal ones for example crackles, wheezes, and pleural rub in order to make correct diagnosis. It is necessary to understand the underlying pathophysiology of various lung sounds generation for better understanding of disease processes. Bedside teaching should be strengthened in order to avoid erosion in this age old procedure in the era of technological explosion. PMID:26229557

TH-EF-BRA-06: A Novel Retrospective 3D K-Space Sorting 4D-MRI Technique Using a Radial K-Space Acquisition MRI Sequence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y; Subashi, E; Yin, F

Purpose: Current retrospective 4D-MRI provides superior tumor-to-tissue contrast and accurate respiratory motion information for radiotherapy motion management. The developed 4D-MRI techniques based on 2D-MRI image sorting require a high frame-rate of the MR sequences. However, several MRI sequences provide excellent image quality but have low frame-rate. This study aims at developing a novel retrospective 3D k-space sorting 4D-MRI technique using radial k-space acquisition MRI sequences to improve 4D-MRI image quality and temporal-resolution for imaging irregular organ/tumor respiratory motion. Methods: The method is based on a RF-spoiled, steady-state, gradient-recalled sequence with minimal echo time. A 3D radial k-space data acquisition trajectorymore » was used for sampling the datasets. Each radial spoke readout data line starts from the 3D center of Field-of-View. Respiratory signal can be extracted from the k-space center data point of each spoke. The spoke data was sorted based on its self-synchronized respiratory signal using phase sorting. Subsequently, 3D reconstruction was conducted to generate the time-resolved 4D-MRI images. As a feasibility study, this technique was implemented on a digital human phantom XCAT. The respiratory motion was controlled by an irregular motion profile. To validate using k-space center data as a respiratory surrogate, we compared it with the XCAT input controlling breathing profile. Tumor motion trajectories measured on reconstructed 4D-MRI were compared to the average input trajectory. The mean absolute amplitude difference (D) was calculated. Results: The signal extracted from k-space center data matches well with the input controlling respiratory profile of XCAT. The relative amplitude error was 8.6% and the relative phase error was 3.5%. XCAT 4D-MRI demonstrated a clear motion pattern with little serrated artifacts. D of tumor trajectories was 0.21mm, 0.23mm and 0.23mm in SI, AP and ML directions, respectively. Conclusion: A novel retrospective 3D k-space sorting 4D-MRI technique has been developed and evaluated on human digital phantom. NIH (1R21CA165384-01A1)« less

Ponto-medullary nuclei involved in the generation of sequential pharyngeal swallowing and concomitant protective laryngeal adduction in situ

PubMed Central

Bautista, Tara G; Dutschmann, Mathias

2014-01-01

Both swallowing and respiration involve postinspiratory laryngeal adduction. Swallowing-related postinspiratory neurons are likely to be located in the nucleus of the solitary tract (NTS) and those involved in respiration are found in the Kölliker–Fuse nucleus (KF). The function of KF and NTS in the generation of swallowing and its coordination with respiration was investigated in perfused brainstem preparations of juvenile rats (n = 41). Orally injected water evoked sequential pharyngeal swallowing (s-PSW) seen as phasic, spindle-shaped bursting of vagal nerve activity (VNA) against tonic postinspiratory discharge. KF inhibition by microinjecting isoguvacine (GABAA receptor agonist) selectively attenuated tonic postinspiratory VNA (n = 10, P < 0.001) but had no effect on frequency or timing of s-PSW. KF disinhibition after bicuculline (GABAA receptor antagonist) microinjections caused an increase of the tonic VNA (n = 8, P < 0.01) resulting in obscured and delayed phasic s-PSW. Occurrence of spontaneous PSW significantly increased after KF inhibition (P < 0.0001) but not after KF disinhibition (P = 0.14). NTS isoguvacine microinjections attenuated the occurrence of all PSW (n = 5, P < 0.01). NTS bicuculline microinjections (n = 6) resulted in spontaneous activation of a disordered PSW pattern and long-lasting suppression of respiratory activity. Pharmacological manipulation of either KF or NTS also triggered profound changes in respiratory postinspiratory VNA. Our results indicate that the s-PSW comprises two functionally distinct components. While the primary s-PSW is generated within the NTS, a KF-mediated laryngeal adductor reflex safeguards the lower airways from aspiration. Synaptic interaction between KF and NTS is required for s-PSW coordination with respiration as well as for proper gating and timing of s-PSW. PMID:24639482

Effects of temperature on complexes I and II mediated respiration, ROS generation and oxidative stress status in isolated gill mitochondria of the mud crab Scylla serrata.

PubMed

Paital, Biswaranjan; Chainy, G B N

2014-04-01

Effects of fluctuations in habitat temperature (18-30°) on mitochondrial respiratory behavior and oxidative metabolic responses in the euryhaline ectotherm Scylla serrata are not fully understood. In the present study, effects of different temperatures ranging from 12 to 40°C on glutamate and succinate mediated mitochondrial respiration, respiratory control ratio (RCR), ATP generation rate, ratio for the utilization of phosphate molecules per atomic oxygen consumption (P/O), levels of lipid peroxidation and H2O2 in isolated gill mitochondria of S. serrata are reported. The pattern of variation in the studied parameters was similar for the two substrates at different temperatures. The values recorded for RCR (≥3) and P/O ratio (1.4-2.7) at the temperature range of 15-25°C were within the normal range reported for other animals (3-10 for RCR and 1.5-3 for P/O). Values for P/O ratio, ATP generation rate and RCR were highest at 18°C when compared to the other assay temperatures. However, at low and high extreme temperatures, i.e. at 12 and 40°C, states III and IV respiration rates were not clearly distinguishable from each other indicating that mitochondria were completely uncoupled. Positive correlations were noticed between temperature and the levels of both lipid peroxidation and H2O2. It is inferred that fluctuations on either side of ambient habitat temperature may adversely influence mitochondrial respiration and oxidative metabolism in S. serrata. The results provide baseline data to understand the impacts of acute changes in temperature on ectotherms inhabiting estuarine or marine environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Control of respiration in fish, amphibians and reptiles.

PubMed

Taylor, E W; Leite, C A C; McKenzie, D J; Wang, T

2010-05-01

Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate the air-breathing organ in air-breathing fishes. Some reptiles retain a buccal force pump for use during hypoxia or exercise. All vertebrates have respiratory rhythm generators (RRG) located in the brainstem. In cyclostomes and possibly jawed fishes, this may comprise elements of the trigeminal nucleus, though in the latter group RRG neurons have been located in the reticular formation. In air-breathing fishes and amphibians, there may be separate RRG for gill and lung ventilation. There is some evidence for multiple RRG in reptiles. Both amphibians and reptiles show episodic breathing patterns that may be centrally generated, though they do respond to changes in oxygen supply. Fish and larval amphibians have chemoreceptors sensitive to oxygen partial pressure located on the gills. Hypoxia induces increased ventilation and a reflex bradycardia and may trigger aquatic surface respiration or air-breathing, though these latter activities also respond to behavioural cues. Adult amphibians and reptiles have peripheral chemoreceptors located on the carotid arteries and central chemoreceptors sensitive to blood carbon dioxide levels. Lung perfusion may be regulated by cardiac shunting and lung ventilation stimulates lung stretch receptors.

Mitochondrial respiratory chain complexes as sources and targets of thiol-based redox-regulation.

PubMed

Dröse, Stefan; Brandt, Ulrich; Wittig, Ilka

2014-08-01

The respiratory chain of the inner mitochondrial membrane is a unique assembly of protein complexes that transfers the electrons of reducing equivalents extracted from foodstuff to molecular oxygen to generate a proton-motive force as the primary energy source for cellular ATP-synthesis. Recent evidence indicates that redox reactions are also involved in regulating mitochondrial function via redox-modification of specific cysteine-thiol groups in subunits of respiratory chain complexes. Vice versa the generation of reactive oxygen species (ROS) by respiratory chain complexes may have an impact on the mitochondrial redox balance through reversible and irreversible thiol-modification of specific target proteins involved in redox signaling, but also pathophysiological processes. Recent evidence indicates that thiol-based redox regulation of the respiratory chain activity and especially S-nitrosylation of complex I could be a strategy to prevent elevated ROS production, oxidative damage and tissue necrosis during ischemia-reperfusion injury. This review focuses on the thiol-based redox processes involving the respiratory chain as a source as well as a target, including a general overview on mitochondria as highly compartmentalized redox organelles and on methods to investigate the redox state of mitochondrial proteins. This article is part of a Special Issue entitled: Thiol-Based Redox Processes. Copyright © 2014 Elsevier B.V. All rights reserved.

DEPOSITION PATTERNS OF RAGWEED POLLEN IN THE HUMAN RESPIRATORY TRACT

EPA Science Inventory

Inhaled particle deposition sites must be identified to effectively treat human airway diseases. e have determined distribution patterns of a selected aeroallergen, ragweed pollen, among human extrathoracic (ET: .e., oro-nasopharyngeal) regions and the lung. A predictive model va...

Visual and Quantitative Analysis Methods of Respiratory Patterns for Respiratory Gated PET/CT.

PubMed

Son, Hye Joo; Jeong, Young Jin; Yoon, Hyun Jin; Park, Jong-Hwan; Kang, Do-Young

2016-01-01

We integrated visual and quantitative methods for analyzing the stability of respiration using four methods: phase space diagrams, Fourier spectra, Poincaré maps, and Lyapunov exponents. Respiratory patterns of 139 patients were grouped based on the combination of the regularity of amplitude, period, and baseline positions. Visual grading was done by inspecting the shape of diagram and classified into two states: regular and irregular. Quantitation was done by measuring standard deviation of x and v coordinates of Poincaré map (SD x , SD v ) or the height of the fundamental peak ( A 1 ) in Fourier spectrum or calculating the difference between maximal upward and downward drift. Each group showed characteristic pattern on visual analysis. There was difference of quantitative parameters (SD x , SD v , A 1 , and MUD-MDD) among four groups (one way ANOVA, p = 0.0001 for MUD-MDD, SD x , and SD v , p = 0.0002 for A 1 ). In ROC analysis, the cutoff values were 0.11 for SD x (AUC: 0.982, p < 0.0001), 0.062 for SD v (AUC: 0.847, p < 0.0001), 0.117 for A 1 (AUC: 0.876, p < 0.0001), and 0.349 for MUD-MDD (AUC: 0.948, p < 0.0001). This is the first study to analyze multiple aspects of respiration using various mathematical constructs and provides quantitative indices of respiratory stability and determining quantitative cutoff value for differentiating regular and irregular respiration.

Mechanisms of CO2/H+ chemoreception by respiratory rhythm generator neurons in the medulla from newborn rats in vitro.

PubMed

Kawai, Akira; Onimaru, Hiroshi; Homma, Ikuo

2006-04-15

We investigated mechanisms of CO(2)/H(+) chemoreception in the respiratory centre of the medulla by measuring membrane potentials of pre-inspiratory neurons, which are putative respiratory rhythm generators, in the brainstem-spinal cord preparation of the neonatal rat. Neuronal response was tested by changing superfusate CO(2) concentration from 2% to 8% at constant HCO(3)(-) concentration (26 mm) or by changing pH from 7.8 to 7.2 by reducing HCO(3)(-) concentration at constant CO(2) (5%). Both respiratory and metabolic acidosis lead to depolarization of neurons with increased excitatory synaptic input and increased burst rate. Respiratory acidosis potentiated the amplitude of the neuronal drive potential. In the presence of tetrodotoxin (TTX), membrane depolarization persisted during respiratory and metabolic acidosis. However, the depolarization was smaller than that before application of TTX, which suggests that some neurons are intrinsically, and others synaptically, chemosensitive to CO(2)/H(+). Application of Ba(2+) blocked membrane depolarization by respiratory acidosis, whereas significant depolarization in response to metabolic acidosis still remained after application of Cd(2+) and Ba(2+). We concluded that the intrinsic responses to CO(2)/H(+)changes were mediated by potassium channels during respiratory acidosis, and that some other mechanisms operate during metabolic acidosis. In low-Ca(2+), high-Mg(2+) solution, an increased CO(2) concentration induced a membrane depolarization with a simultaneous increase of the burst rate. Pre-inspiratory neurons could adapt their baseline membrane potential to external CO(2)/H(+) changes by integration of these mechanisms to modulate their burst rates. Thus, pre-inspiratory neurons might play an important role in modulation of respiratory rhythm by central chemoreception in the brainstem-spinal cord preparation.

Mechanisms of CO2/H+ chemoreception by respiratory rhythm generator neurons in the medulla from newborn rats in vitro

PubMed Central

Kawai, Akira; Onimaru, Hiroshi; Homma, Ikuo

2006-01-01

We investigated mechanisms of CO2/H+ chemoreception in the respiratory centre of the medulla by measuring membrane potentials of pre-inspiratory neurons, which are putative respiratory rhythm generators, in the brainstem–spinal cord preparation of the neonatal rat. Neuronal response was tested by changing superfusate CO2 concentration from 2% to 8% at constant HCO3− concentration (26 mm) or by changing pH from 7.8 to 7.2 by reducing HCO3− concentration at constant CO2 (5%). Both respiratory and metabolic acidosis lead to depolarization of neurons with increased excitatory synaptic input and increased burst rate. Respiratory acidosis potentiated the amplitude of the neuronal drive potential. In the presence of tetrodotoxin (TTX), membrane depolarization persisted during respiratory and metabolic acidosis. However, the depolarization was smaller than that before application of TTX, which suggests that some neurons are intrinsically, and others synaptically, chemosensitive to CO2/H+. Application of Ba2+ blocked membrane depolarization by respiratory acidosis, whereas significant depolarization in response to metabolic acidosis still remained after application of Cd2+ and Ba2+. We concluded that the intrinsic responses to CO2/H+changes were mediated by potassium channels during respiratory acidosis, and that some other mechanisms operate during metabolic acidosis. In low-Ca2+, high-Mg2+ solution, an increased CO2 concentration induced a membrane depolarization with a simultaneous increase of the burst rate. Pre-inspiratory neurons could adapt their baseline membrane potential to external CO2/H+ changes by integration of these mechanisms to modulate their burst rates. Thus, pre-inspiratory neurons might play an important role in modulation of respiratory rhythm by central chemoreception in the brainstem–spinal cord preparation. PMID:16469786

Pre-Bötzinger Complex Receives Glutamatergic Innervation From Galaninergic and Other Retrotrapezoid Nucleus Neurons

PubMed Central

Bochorishvili, Genrieta; Stornetta, Ruth L.; Coates, Melissa B.; Guyenet, Patrice G.

2014-01-01

The retrotrapezoid nucleus (RTN) contains CO2-responsive neurons that regulate breathing frequency and amplitude. These neurons (RTN-Phox2b neurons) contain the transcription factor Phox2b, vesicular glutamate transporter 2 (VGLUT2) mRNA, and a subset contains preprogalanin mRNA. We wished to determine whether the terminals of RTN-Phox2b neurons contain galanin and VGLUT2 proteins, to identify the specific projections of the galaninergic subset, to test whether RTN-Phox2b neurons contact neurons in the pre-Bötzinger complex, and to identify the ultrastructure of these synapses. The axonal projections of RTN-Phox2b neurons were traced by using biotinylated dextran amine (BDA), and many BDA-ir boutons were found to contain galanin immunoreactivity. RTN galaninergic neurons had ipsilateral projections that were identical with those of this nucleus at large: the ventral respiratory column, the caudolateral nucleus of the solitary tract, and the pontine Köliker-Fuse, intertrigeminal region, and lateral parabrachial nucleus. For ultrastructural studies, RTN-Phox2b neurons (galaninergic and others) were transfected with a lentiviral vector that expresses mCherry almost exclusively in Phox2b-ir neurons. After spinal cord injections of a catecholamine neuron-selective toxin, there was a depletion of C1 neurons in the RTN area; thus it was determined that the mCherry-positive terminals located in the pre-Bötzinger complex originated almost exclusively from the RTN-Phox2b (non-C1) neurons. These terminals were generally VGLUT2-immunoreactive and formed numerous close appositions with neurokinin-1 receptor-ir pre-Bötzinger complex neurons. Their boutons (n = 48) formed asymmetric synapses filled with small clear vesicles. In summary, RTN-Phox2b neurons, including the galaninergic subset, selectively innervate the respiratory pattern generator plus a portion of the dorsolateral pons. RTN-Phox2b neurons establish classic excitatory glutamatergic synapses with pre-Bötzinger complex neurons presumed to generate the respiratory rhythm. PMID:21935944

Analysis of respiratory and muscle activity by means of cross information function between ventilatory and myographic signals.

PubMed

Alonso, J F; Mañanas, M A; Hoyer, D; Topor, Z L; Bruce, E N

2004-01-01

Analysis of respiratory muscle activity is a promising technique for the study of pulmonary diseases such as obstructive sleep apnea syndrome (OSAS). Evaluation of interactions between muscles is very useful in order to determine the muscular pattern during an exercise. These interactions have already been assessed by means of different linear techniques like cross-spectrum, magnitude squared coherence or cross-correlation. The aim of this work is to evaluate interactions between respiratory and myographic signals through nonlinear analysis by means of cross mutual information function (CMIF), and finding out what information can be extracted from it. Some parameters are defined and calculated from CMIF between ventilatory and myographic signals of three respiratory muscles. Finally, differences in certain parameters were obtained between OSAS patients and healthy subjects indicating different respiratory muscle couplings.

Acute respiraotry diseases in students at the University of the Philippines, 1964-69.

PubMed

Evans, A S; Espiritu-Campos, L

1971-01-01

Acute respiratory infections have been found to be a common cause of morbidity in young adults in the tropical setting of the Philippines, with incidence rates equalling those of colder northern countries. Influenza outbreaks have occurred as part of a worldwide pattern and parainfluenza infections are common, as revealed by serological tests on such students. About half of the respiratory infections could be identified etiologically. In contrast, clinical infections from group A haemolytic streptococci, Mycoplasma pneumoniae, adenoviruses, and infections due to Epstein-Barr virus (infectious mononucleosis) were rare in this population. The role of prior immunity is discussed in relation to these patterns.

Cell-specific Expression of CYP2A5 in the Mouse Respiratory Tract: Effects of Olfactory Toxicants

PubMed Central

Piras, Elena; Franzén, Anna; Fernández, Estíbaliz L.; Bergström, Ulrika; Raffalli-Mathieu, Françoise; Lang, Matti; Brittebo, Eva B.

2003-01-01

We performed a detailed analysis of mouse cytochrome P450 2A5 (CYP2A5) expression by in situ hybridization (ISH) and immunohistochemistry (IHC) in the respiratory tissues of mice. The CYP2A5 mRNA and the corresponding protein co-localized at most sites and were predominantly detected in the olfactory region, with an expression in sustentacular cells, Bowman's gland, and duct cells. In the respiratory and transitional epithelium there was no or only weak expression. The nasolacrimal duct and the excretory ducts of nasal and salivary glands displayed expression, whereas no expression occurred in the acini. There was decreasing expression along the epithelial linings of the trachea and lower respiratory tract, whereas no expression occurred in the alveoli. The hepatic CYP2A5 inducers pyrazole and phenobarbital neither changed the CYP2A5 expression pattern nor damaged the olfactory mucosa. In contrast, the olfactory toxicants dichlobenil and methimazole induced characteristic changes. The damaged Bowman's glands displayed no expression, whereas the damaged epithelium expressed the enzyme. The CYP2A5 expression pattern is in accordance with previously reported localization of protein and DNA adducts and the toxicity of some CYP2A5 substrates. This suggests that CYP2A5 is an important determinant for the susceptibility of the nasal and respiratory epithelia to protoxicants and procarcinogens. PMID:14566026

Development of respiratory rhythms in perinatal chick embryos.

PubMed

Chiba, Y; Khandoker, A H; Nobuta, M; Moriya, K; Akiyama, R; Tazawa, H

2002-04-01

In chick embryos, gas exchange takes place via the chorioallantoic membrane (CAM) and the lungs at approximately 1 day prior to hatching. The present study was designed to elucidate the development of respiratory rhythms in the chick embryo during the whole pipping (perinatal) period with a condenser-microphone measuring system. The microphone was hermetically attached on the eggshell over the air cell on day 18 of incubation. It first detected a cardiogenic signal (i.e. acoustocardiogram), and then beak clapping and breathing signals (acoustorespirogram, ARG). The first signals of lung ventilation appeared intermittently and irregularly approximately once per 5 s among the clapping signals after the embryo penetrated its beak into the air cell (internal pipping, IP). The respiratory rhythm then developed irregularly, with a subsequent more regular rate. The envelope pattern of breathing from the onset of IP through external pipping (EP) to hatching was constructed by a specially devised procedure, which eliminated external and internal noises. The envelope patterns indicated that the IP, EP and whole perinatal periods of 10 embryos were 14.1+/-6.4 (S.D.), 13.6+/-4.0 and 27.6+/-5.4 h, respectively. In addition, they also indicated the period of embryonic hatching activity (i.e. climax) which was 48+/-19 min. The development of respiratory rhythm was also shown by the instantaneous respiratory rate (IRR) which was designated as an inverse value of two adjacent ARG waves.

Image acquisition optimization of a limited-angle intrafraction verification (LIVE) system for lung radiotherapy.

PubMed

Zhang, Yawei; Deng, Xinchen; Yin, Fang-Fang; Ren, Lei

2018-01-01

Limited-angle intrafraction verification (LIVE) has been previously developed for four-dimensional (4D) intrafraction target verification either during arc delivery or between three-dimensional (3D)/IMRT beams. Preliminary studies showed that LIVE can accurately estimate the target volume using kV/MV projections acquired over orthogonal view 30° scan angles. Currently, the LIVE imaging acquisition requires slow gantry rotation and is not clinically optimized. The goal of this study is to optimize the image acquisition parameters of LIVE for different patient respiratory periods and gantry rotation speeds for the effective clinical implementation of the system. Limited-angle intrafraction verification imaging acquisition was optimized using a digital anthropomorphic phantom (XCAT) with simulated respiratory periods varying from 3 s to 6 s and gantry rotation speeds varying from 1°/s to 6°/s. LIVE scanning time was optimized by minimizing the number of respiratory cycles needed for the four-dimensional scan, and imaging dose was optimized by minimizing the number of kV and MV projections needed for four-dimensional estimation. The estimation accuracy was evaluated by calculating both the center-of-mass-shift (COMS) and three-dimensional volume-percentage-difference (VPD) between the tumor in estimated images and the ground truth images. The robustness of LIVE was evaluated with varied respiratory patterns, tumor sizes, and tumor locations in XCAT simulation. A dynamic thoracic phantom (CIRS) was used to further validate the optimized imaging schemes from XCAT study with changes of respiratory patterns, tumor sizes, and imaging scanning directions. Respiratory periods, gantry rotation speeds, number of respiratory cycles scanned and number of kV/MV projections acquired were all positively correlated with the estimation accuracy of LIVE. Faster gantry rotation speed or longer respiratory period allowed less respiratory cycles to be scanned and less kV/MV projections to be acquired to estimate the target volume accurately. Regarding the scanning time minimization, for patient respiratory periods of 3-4 s, gantry rotation speeds of 1°/s, 2°/s, 3-6°/s required scanning of five, four, and three respiratory cycles, respectively. For patient respiratory periods of 5-6 s, the corresponding respiratory cycles required in the scan changed to four, three, and two cycles, respectively. Regarding the imaging dose minimization, for patient respiratory periods of 3-4 s, gantry rotation speeds of 1°/s, 2-4°/s, 5-6°/s required acquiring of 7, 5, 4 kV and MV projections, respectively. For patient respiratory periods of 5-6 s, 5 kV and 5 MV projections are sufficient for all gantry rotation speeds. The optimized LIVE system was robust against breathing pattern, tumor size and tumor location changes. In the CIRS study, the optimized LIVE system achieved the average center-of-mass-shift (COMS)/volume-percentage-difference (VPD) of 0.3 ± 0.1 mm/7.7 ± 2.0% for the scanning time priority case, 0.2 ± 0.1 mm/6.1 ± 1.2% for the imaging dose priority case, respectively, among all gantry rotation speeds tested. LIVE was robust against different scanning directions investigated. The LIVE system has been preliminarily optimized for different patient respiratory periods and treatment gantry rotation speeds using digital and physical phantoms. The optimized imaging parameters, including number of respiratory cycles scanned and kV/MV projection numbers acquired, provide guidelines for optimizing the scanning time and imaging dose of the LIVE system for its future evaluations and clinical implementations through patient studies. © 2017 American Association of Physicists in Medicine.

Impact of nasopharyngeal microbiota on the development of respiratory tract diseases.

PubMed

Esposito, S; Principi, N

2018-01-01

Knowledge of whether and how respiratory microbiota composition can prime the immune system and provide colonisation resistance, limiting consecutive pathobiont overgrowth and infections, is essential to improving the prevention and therapy of respiratory disorders. Modulation of dysbiotic ecosystems or reconstitution of missing microbes might be a possible measure to reduce respiratory diseases. The aim of this review is to analyse the role of nasopharyngeal microbiota in the development of respiratory tract disease in paediatric-age subjects. PubMed was used to search for all studies published over the last 15 years using the following key words: "microbiota" or "microbioma" and "nasopharyngeal" or "respiratory" or "nasal" and "children" or "paediatric" or "infant". Analysis of the literature showed that respiratory microbiota can regulate health and disease development in the respiratory tract. Like the gut microbiota, the respiratory microbiota is established at birth, and early respiratory microbiota composition determines bacterial succession patterns and respiratory health in children. Protective and dangerous bacteria have been identified, and this can be considered the base for developing new approaches to diseases that respond poorly to traditional interventions. Reconstitution of missing microbes can be achieved by the administration of pre- and probiotics. Modulation of respiratory microbiota by favouring colonisation of the upper respiratory tract by beneficial commensals can interfere with the proliferation and activity of resident pathobionts and is a possible new measure to reduce the risk of disease. However, further studies are needed because a deeper understanding of these and related issues can be transferred to clinical practice.

Drug utilization review of cephalosporins in a secondary care hospital in United Arab Emirates.

PubMed

Abou-Shaaban, Mohammad; Ali, Areeg Anwer; Rao, Padma G M; Majid, Asif

2016-12-01

Background Cephalosporins are one of the most commonly used antibiotics in United Arab Emirates (UAE). Few studies have been carried out to evaluate the antibiotic utilization pattern in UAE in spite of the obvious increase in cephalosporins resistance during the past decade. Objective To assess the prescriptions pattern of cephalosporins among physicians at a secondary care hospital in Ras Al Khaimah, UAE. Method This observational prospective study was carried out during October 2013 to April 2014. The data of in patients were documented in the predesigned patient profile form and was analyzed for patient's, drug's and drug's therapy related parameters. Results The 3rd generation cephalosporins constituted 83.6 % of the prescriptions, with ceftriaxone being the most commonly used one (81.1 %). They were mainly prescribed for the treatment of the lower respiratory tract infections (60.2 %). Seven (3.5 %) different ADRs linked to cephalosporin use were observed ranging from oral thrush to clostridium difficile infection. A total of 1039 antimicrobial and nonantimicrobial medications were prescribed concomitantly with cephalosporins. Conclusion The 3rd generation cephalosporins were commonly prescribed by parenteral route. Thus, there is a strong need for rationalizing their use to preserve their efficacy and prevent the development of resistance in the region.

Effect of Cues to Increase Sound Pressure Level on Respiratory Kinematic Patterns during Connected Speech

ERIC Educational Resources Information Center

Huber, Jessica E.

2007-01-01

Purpose: This study examined the response of the respiratory system to 3 cues used to elicit increased vocal loudness to determine whether the effects of cueing, shown previously in sentence tasks, were present in connected speech tasks and to describe differences among tasks. Method: Fifteen young men and 15 young women produced a 2-paragraph…

EFFECT OF RAPID SHALLOW BREATHING ON THE DISTRIBUTION OF 18-O-LABELED OZONE REACTION PRODUCT IN THE RESPIRATORY TRACT OF THE RAT

EPA Science Inventory

We examined the effect of breathing pattern on ozone reaction product content within the respiratory tract. Thirty-four anesthetized, maleWistar rats were exposed to oxygen-18 (18O)-labeled ozone at 1.0 ppm for 2 h using a dual-chamber, negative-pressure ventilation system. Fre...

Respiratory Sinus Arrhythmia as an Index of Vagal Activity during Stress in Infants: Respiratory Influences and Their Control

PubMed Central

Ritz, Thomas; Bosquet Enlow, Michelle; Schulz, Stefan M.; Kitts, Robert; Staudenmayer, John; Wright, Rosalind J.

2012-01-01

Respiratory sinus arrhythmia (RSA) is related to cardiac vagal outflow and the respiratory pattern. Prior infant studies have not systematically examined respiration rate and tidal volume influences on infant RSA or the extent to which infants' breathing is too fast to extract a valid RSA. We therefore monitored cardiac activity, respiration, and physical activity in 23 six-month old infants during a standardized laboratory stressor protocol. On average, 12.6% (range 0–58.2%) of analyzed breaths were too short for RSA extraction. Higher respiration rate was associated with lower RSA amplitude in most infants, and lower tidal volume was associated with lower RSA amplitude in some infants. RSA amplitude corrected for respiration rate and tidal volume influences showed theoretically expected strong reductions during stress, whereas performance of uncorrected RSA was less consistent. We conclude that stress-induced changes of peak-valley RSA and effects of variations in breathing patterns on RSA can be determined for a representative percentage of infant breaths. As expected, breathing substantially affects infant RSA and needs to be considered in studies of infant psychophysiology. PMID:23300753

Acute pulmonary and innate immunity health effects in mice inhaling cookstove emissions

EPA Science Inventory

Background: Burning of solid-fuels in rudimentary stoves generates harmful emissions that contribute to poor indoor air quality and have detrimental impacts on human health. Acute health effects include respiratory and eye irritation, cough, acute lower respiratory infection and ...

The pattern of pediatric respiratory illnesses admitted in ebonyi state university teaching hospital South-East Nigeria.

PubMed

Ezeonu, Ct; Uneke, Cj; Ojukwu, Jo; Anyanwu, Ou; Okike, Co; Ezeanosike, Ob; Agumadu, Hu

2015-01-01

Reports from the developed nations reveal respiratory tract infections as the leading cause of childhood hospital admissions. Children may be admitted for a variety of respiratory illnesses. Data on the spectrum of pediatric respiratory illnesses admitted in the hospital is scarce. To determine the pattern of pediatrics respiratory illness admissions, seasonal frequency, underlying risk factors and outcome. A retrospective assessment of respiratory cases admitted in the pediatric ward from 2005 to 2010 was conducted using case notes. Parameters considered included month of presentation, age, sex, immunization and nutritional status, tools of diagnosis and patient outcome. Results were analyzed using the Statistical Package for the Social Sciences with the level of significance P ≤ 0.05. Of the 239 cases admitted, there were more males than females (1.4:1). The commonest case was Bronchopneumonia, 71.6% (171/239 out of which 161 were uncomplicated, 5 had effusions and 6 were associated with measles). Other cases were Pulmonary Tuberculosis, 10.9% (26/239), Lobar pneumonia 8.8% (21/239), Bronchiolitis, 5% (12/239), Aspiration pneumonitis 2.1% (5/239) and Bronchial asthma, 0.8% (2/239). Mortality was 7.5% (18/239) mostly from Bronchopneumonia amongst the 1-5 years old. Mortality was significantly associated with malnutrition (P < 0.001) and poor immunization status (P < 0.01). Bronchopneumonia was found to be the commonest illness with significant mortality and peak occurrence in the rainy season. More emphasis must be laid on anticipatory guidance and prevention by encouraging the immunization, good nutrition and increased attention on children even after 1 year of age.

The role of alternative oxidase in tomato fruit ripening and its regulatory interaction with ethylene

PubMed Central

Lin, Hong-Hui

2012-01-01

Although the alternative oxidase (AOX) has been proposed to play a role in fruit development, the function of AOX in fruit ripening is unclear. To gain further insight into the role of AOX in tomato fruit ripening, transgenic tomato plants 35S-AOX1a and 35S-AOX-RNAi were generated. Tomato plants with reduced LeAOX levels exhibited retarded ripening; reduced carotenoids, respiration, and ethylene production; and the down-regulation of ripening-associated genes. Moreover, no apparent respiratory climacteric occurred in the AOX-reduced tomato fruit, indicating that AOX might play an important role in climacteric respiration. In contrast, the fruit that overexpressed LeAOX1a accumulated more lycopene, though they displayed a similar pattern of ripening to wild-type fruit. Ethylene application promoted fruit ripening and anticipated ethylene production and respiration, including the alternative pathway respiration. Interestingly, the transgenic plants with reduced LeAOX levels failed to ripen after 1-methylcyclopropene (1-MCP) treatment, while such inhibition was notably less effective in 35S-AOX1a fruit. These findings indicate that AOX is involved in respiratory climacteric and ethylene-mediated fruit ripening of tomato. PMID:22915749

The effects of locomotor-respiratory coupling on the pattern of breathing in horses.

PubMed Central

Lafortuna, C L; Reinach, E; Saibene, F

1996-01-01

1. To investigate the effect of locomotor activity on the pattern of breathing in quadrupeds, ventilatory response was studied in four healthy horses during horizontal and inclined (7%) treadmill exercise at different velocities (1.4-6.9 m s(-1)) and during chemical stimulation with a rebreathing method. Stride frequency (f(s)) and locomotor-respiratory coupling (LRC) were also simultaneously determined by means of video recordings synchronized with respiratory events. 2. Tidal volume (V(T)) was positively correlated with pulmonary ventilation (V(E)) but significantly different linear regression equations were found between the experimental conditions (P < 0.0001), since the chemical hyperventilation was mainly due to increases in V(T), whereas the major contribution to exercise hyperpnoea came from changes in respiratory frequency (f(R)). 3. The average f(R) at each exercise level was not significantly different from f(S), although there was not always a tight 1:1 LRC. At constant speeds, f(S) was independent of the treadmill slope and hence the greater V(E) during inclined exercise was due to increased V(T). 4. At any ventilatory level, the differences in breathing patterns between locomotion and rebreathing or locomotion at different slopes derived from different set points of the inspiratory off-switch mechanism. 5. The percentage of single breaths entrained with locomotor rhythm rose progressively and significantly with treadmill speed (P < 0.0001) up to a 1:1 LRC and was significantly affected by treadmill slope (P < 0.001). 6. A LRC of 1:1 was systematically observed at canter (10 out of 10 trials) and sometimes at trot (5 out of 14) and it entailed (i) a 4- to 5-fold reduction in both V(T) and f(R) variability, and (ii) a gait-specific phase locking of inspiratory onset during the locomotor cycle. 7. It is concluded that different patterns of breathing are employed during locomotion and rebreathing due to the interference between locomotor and respiratory functions, which may play a role in the optimization and control of exercise ventilation in horses. PMID:9019552

Changing patterns of inpatient respiratory care services over a decade at the Cleveland Clinic: challenges posed and proposed responses.

PubMed

Orens, Douglas K; Kester, Lucy; Konrad, Dale J; Stoller, James K

2005-08-01

Changing characteristics of hospitalized patients over the last decade have created challenges for all health-care providers in delivering optimal care. In the specific case of respiratory care, trends that hospitalized patients have generally become sicker over time and that average lengths of stay have generally become shorter have posed the challenge of meeting demands for more services delivered with greater immediacy. We undertook the current analysis to assess how the delivery of respiratory care services at a tertiary-care academic medical center, the Cleveland Clinic Foundation Hospital, has evolved over the decade 1991 to 2001. In this observational study, we examined concurrent departmental trends and speculated that the capability to increase clinical activity with maintained or improved clinical outcomes, preserved costs, and a lower turnover rate among respiratory therapists reflects features of the professional environment within our Section of Respiratory Therapy. This analysis compares patterns of respiratory care service delivery in two 5-year intervals: from 1991 to 1996 and from 1996 to 2001. Data were collected using a respiratory care information-management system and an inpatient hospital information system, which track the volume and actual cost of services provided. These analyses accounted for the actual time-based cost of the services, including labor (with benefits), necessary equipment and supplies, medications, and equipment maintenance and depreciation. Hospital case-mix index values were determined according to guidelines from the Centers for Medicare and Medicaid Services, as the weighted average of resource allocation scores assigned to diagnosis-related-group categories of hospitalized patients. From 1991 to 2001, there were important expansions in the scope of respiratory care practice by our Section of Respiratory Care, while the volume of respiratory care services delivered per year increased 1.96-fold (from 339,600 to 665,921 services/y). The number of respiratory therapy consults performed yearly, beginning in 1992 when the service was first implemented, rose to over 10,000/y by 2001. At the same time, the cost of respiratory therapy services delivered per patient decreased by 4.2%. Regarding staffing trends, the number of full-time-equivalent employees increased by 50% (from 65 to 97.5). However, the percent turnover rate among respiratory therapists decreased by 2.3-fold (from 11.5% to 5%). In the face of these trends, the hospital mortality rate for patients with diagnosis-related group 088 (high users of respiratory care services) decreased by 53%, and the length of hospital stay for all patients receiving respiratory treatments decreased by 30%. This analysis shows that trends of growing demands for respiratory care services have been accompanied by generally improving clinical outcomes and favorable retention of respiratory therapists in our section. We believe that a focus on the process of care, including enhanced professionalism, communication, and participation, has permitted a favorable response to these rising demands.

Computationally efficient analysis of particle transport and deposition in a human whole-lung-airway model. Part I: Theory and model validation.

PubMed

Kolanjiyil, Arun V; Kleinstreuer, Clement

2016-12-01

Computational predictions of aerosol transport and deposition in the human respiratory tract can assist in evaluating detrimental or therapeutic health effects when inhaling toxic particles or administering drugs. However, the sheer complexity of the human lung, featuring a total of 16 million tubular airways, prohibits detailed computer simulations of the fluid-particle dynamics for the entire respiratory system. Thus, in order to obtain useful and efficient particle deposition results, an alternative modeling approach is necessary where the whole-lung geometry is approximated and physiological boundary conditions are implemented to simulate breathing. In Part I, the present new whole-lung-airway model (WLAM) represents the actual lung geometry via a basic 3-D mouth-to-trachea configuration while all subsequent airways are lumped together, i.e., reduced to an exponentially expanding 1-D conduit. The diameter for each generation of the 1-D extension can be obtained on a subject-specific basis from the calculated total volume which represents each generation of the individual. The alveolar volume was added based on the approximate number of alveoli per generation. A wall-displacement boundary condition was applied at the bottom surface of the first-generation WLAM, so that any breathing pattern due to the negative alveolar pressure can be reproduced. Specifically, different inhalation/exhalation scenarios (rest, exercise, etc.) were implemented by controlling the wall/mesh displacements to simulate realistic breathing cycles in the WLAM. Total and regional particle deposition results agree with experimental lung deposition results. The outcomes provide critical insight to and quantitative results of aerosol deposition in human whole-lung airways with modest computational resources. Hence, the WLAM can be used in analyzing human exposure to toxic particulate matter or it can assist in estimating pharmacological effects of administered drug-aerosols. As a practical WLAM application, the transport and deposition of asthma drugs from a commercial dry-powder inhaler is discussed in Part II. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Influenza Vaccination on Acute Respiratory Symptoms in Malaysian Hajj Pilgrims.

PubMed

Hasan, Habsah; Deris, Zakuan Zainy; Sulaiman, Siti Amrah; Abdul Wahab, Mohd Suhaimi; Naing, Nyi Nyi; Ab Rahman, Zulkefle; Othman, Nor Hayati

2015-08-01

Respiratory illness were a major problem and caused high hospital admission during hajj seasons. One of the contributing cause to this illness is infection. Various measures had been implemented to reduce respiratory infections. The aim on the study is to determine the effect of influenza vaccination against acute respiratory illness among Malaysian Hajj pilgrims. This is an observational cohort study. Influenza vaccination was given to pilgrims at least 2 weeks prior to departure. The occurrence of symptoms for respiratory illness such as cough, fever, sore throat and runny nose was monitored daily for 6 weeks during pilgrimage using a health diary. A total of 65 vaccinated hajj pilgrims and 41 controls were analyzed. There was no significant difference in pattern of occurrence of symptoms of respiratory illness by duration of pilgrimage as well as the number of symptoms between both groups. Hajj pilgrims have frequent respiratory symptoms. We were unable to document benefit from influenza vaccination, but our study was limited by a small sample size and lack of laboratory testing for influenza.

Particle retention by respiratory epithelial cells is associated with persistent biological effect

EPA Science Inventory

The biological effect of particles on respiratory epithelial cells involves, in part, the generation of an oxidative stress and a consequent cascade of reactions culminating in inflammatory mediator release. Whether there is either an immediate, transitory activation or a persist...

Replication and Shedding of MERS-CoV in Upper Respiratory Tract of Inoculated Dromedary Camels

PubMed Central

Adney, Danielle R.; van Doremalen, Neeltje; Brown, Vienna R.; Bushmaker, Trenton; Scott, Dana; de Wit, Emmie; Munster, Vincent J.

2014-01-01

In 2012, a novel coronavirus associated with severe respiratory disease in humans emerged in the Middle East. Epidemiologic investigations identified dromedary camels as the likely source of zoonotic transmission of Middle East respiratory syndrome coronavirus (MERS-CoV). Here we provide experimental support for camels as a reservoir for MERS-CoV. We inoculated 3 adult camels with a human isolate of MERS-CoV and a transient, primarily upper respiratory tract infection developed in each of the 3 animals. Clinical signs of the MERS-CoV infection were benign, but each of the camels shed large quantities of virus from the upper respiratory tract. We detected infectious virus in nasal secretions through 7 days postinoculation, and viral RNA up to 35 days postinoculation. The pattern of shedding and propensity for the upper respiratory tract infection in dromedary camels may help explain the lack of systemic illness among naturally infected camels and the means of efficient camel-to-camel and camel-to-human transmission. PMID:25418529

Correction of respiratory disorders in a mouse model of Rett syndrome

PubMed Central

Abdala, Ana P. L.; Dutschmann, Mathias; Bissonnette, John M.; Paton, Julian F. R.

2010-01-01

Rett syndrome (RTT) is an autism spectrum disorder caused by mutations in the X-linked gene that encodes the transcription factor methyl-CpG-binding protein 2 (MeCP2). A major debilitating phenotype in affected females is frequent apneas, and heterozygous Mecp2-deficient female mice mimic the human respiratory disorder. GABA defects have been demonstrated in the brainstem of Mecp2-deficient mice. Here, using an intact respiratory network, we show that apnea in RTT mice is characterized by excessive excitatory activity in expiratory cranial and spinal nerves. Augmenting GABA markedly improves the respiratory phenotype. In addition, a serotonin 1a receptor agonist that depresses expiratory neuron activity also reduces apnea, corrects the irregular breathing pattern, and prolongs survival in MeCP2 null males. Combining a GABA reuptake blocker with a serotonin 1a agonist in heterozygous females completely corrects their respiratory defects. The results indicate that GABA and serotonin 1a receptor activity are candidates for treatment of the respiratory disorders in Rett syndrome. PMID:20921395

Mucosal immunoglobulins at respiratory surfaces mark an ancient association that predates the emergence of tetrapods

PubMed Central

Xu, Zhen; Takizawa, Fumio; Parra, David; Gómez, Daniela; von Gersdorff Jørgensen, Louise; LaPatra, Scott E.; Sunyer, J. Oriol

2016-01-01

Gas-exchange structures are critical for acquiring oxygen, but they also represent portals for pathogen entry. Local mucosal immunoglobulin responses against pathogens in specialized respiratory organs have only been described in tetrapods. Since fish gills are considered a mucosal surface, we hypothesized that a dedicated mucosal immunoglobulin response would be generated within its mucosa on microbial exposure. Supporting this hypothesis, here we demonstrate that following pathogen exposure, IgT+ B cells proliferate and generate pathogen-specific IgT within the gills of fish, thus providing the first example of locally induced immunoglobulin in the mucosa of a cold-blooded species. Moreover, we demonstrate that gill microbiota is predominantly coated with IgT, thus providing previously unappreciated evidence that the microbiota present at a respiratory surface of a vertebrate is recognized by a mucosal immunoglobulin. Our findings indicate that respiratory surfaces and mucosal immunoglobulins are part of an ancient association that predates the emergence of tetrapods. PMID:26869478

Middle East respiratory syndrome in children. Dental considerations.

PubMed

Al-Sehaibany, Fares S

2017-04-01

As of January 2016, 1,633 laboratory-confirmed cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection and 587 MERS-related deaths have been reported by the World Health Organization globally. Middle East Respiratory Syndrome Coronavirus  may occur sporadically in communities or may be transmitted within families or hospitals. The number of confirmed MERS-CoV cases among healthcare workers has been increasing. Middle East Respiratory Syndrome Coronavirus may also spread through aerosols generated during various dental treatments, resulting in transmission between patients and dentists. As MERS-CoV cases have also been reported among children, pediatric dentists are at risk of MERS-CoV infection. This review discusses MERS-CoV infection in children and healthcare workers, especially pediatric dentists, and considerations pertaining to pediatric dentistry. Although no cases of MERS-CoV transmission between a patient and a dentist have yet been reported, the risk of MERS-CoV transmission from an infected patient may be high due to the unique work environment of dentists (aerosol generation).

[Development of expert diagnostic system for common respiratory diseases].

PubMed

Xu, Wei-hua; Chen, You-ling; Yan, Zheng

2014-03-01

To develop an internet-based expert diagnostic system for common respiratory diseases. SaaS system was used to build architecture; pattern of forward reasoning was applied for inference engine design; ASP.NET with C# from the tool pack of Microsoft Visual Studio 2005 was used for website-interview medical expert system.The database of the system was constructed with Microsoft SQL Server 2005. The developed expert system contained large data memory and high efficient function of data interview and data analysis for diagnosis of various diseases.The users were able to perform this system to obtain diagnosis for common respiratory diseases via internet. The developed expert system may be used for internet-based diagnosis of various respiratory diseases,particularly in telemedicine setting.

Respiratory Magnetogram Detected with a MEMS Device

PubMed Central

Dominguez-Nicolas, Saul M.; Juarez-Aguirre, Raul; Herrera-May, Agustin L.; Garcia-Ramirez, Pedro; Figueras, Eduard; Gutierrez-D., Edmundo A.; Tapia, Jesus A.; Trejo, Argelia; Manjarrez, Elias

2013-01-01

Magnetic fields generated by the brain or the heart are very useful in clinical diagnostics. Therefore, magnetic signals produced by other organs are also of considerable interest. Here we show first evidence that thoracic muscles can produce a strong magnetic flux density during respiratory activity, that we name respiratory magnetogram. We used a small magnetometer based on microelectromechanical systems (MEMS), which was positioned inside the open thoracic cage of anaesthetized and ventilated rats. With this new MEMS sensor of about 20 nT resolution, we recorded a strong and rhythmic respiratory magnetogram of about 600 nT. PMID:24046516

A new paradigm in respiratory hygiene: modulating respiratory secretions to contain cough bioaerosol without affecting mucus clearance

PubMed Central

Zayas, Gustavo; Valle, Juan C; Alonso, Mauricio; Alfaro, Henry; Vega, Daniel; Bonilla, Gloria; Reyes, Miguel; King, Malcolm

2007-01-01

Background Several strategies and devices have been designed to protect health care providers from acquiring transmissible respiratory diseases while providing care. In modulating the physical characteristics of the respiratory secretions to minimize the aerosolization that facilitates transmission of airborne diseases, a fundamental premise is that the prototype drugs have no adverse effect on the first line of respiratory defense, clearance of mucus by ciliary action. Methods To assess and demonstrate the primary mechanism of our mucomodulators (XLs), we have built our evidence moving from basic laboratory studies to an ex-vivo model and then to an in-vivo large animal model. We exposed anesthetized dogs without hypersecretion to different dose concentrations of aerosolized XL "B", XL "D" and XL "S". We assessed: cardio-respiratory pattern, tracheal mucus clearance, airway patency, and mucus viscoelastic changes. Results Exposure of frog palate mucus to XLs did not affect the clearance of mucus by ciliary action. Dogs maintained normal cardio-respiratory pattern with XL administration. Tracheal mucociliary clearance in anesthetized dogs indicated a sustained 40% mean increase. Tracheal mucus showed increased filance, and there was no mucus retention in the airways. Conclusion The ex-vivo frog palate and the in-vivo mammalian models used in this study, appear to be appropriate and complement each other to better assess the effects that our mucomodulators exert on the mucociliary clearance defence mechanism. The physiological function of the mucociliary apparatus was not negatively affected in any of the two epithelial models. Airway mucus crosslinked by mucomodulators is better cleared from an intact airway and normally functioning respiratory system, either due to enhanced interaction with cilia or airflow-dependent mechanisms. Data obtained in this study allow us to assure that we have complied with the fundamental requirement criteria established in the initial phase of developing the concept of mucomodulation: Can we modulate the physical characteristics of the respiratory secretions to reduce aerosolization without affecting normal mucociliary clearance function, or even better improving it? PMID:17697323

A Molecular atlas of Xenopus respiratory system development.

PubMed

Rankin, Scott A; Thi Tran, Hong; Wlizla, Marcin; Mancini, Pamela; Shifley, Emily T; Bloor, Sean D; Han, Lu; Vleminckx, Kris; Wert, Susan E; Zorn, Aaron M

2015-01-01

Respiratory system development is regulated by a complex series of endoderm-mesoderm interactions that are not fully understood. Recently Xenopus has emerged as an alternative model to investigate early respiratory system development, but the extent to which the morphogenesis and molecular pathways involved are conserved between Xenopus and mammals has not been systematically documented. In this study, we provide a histological and molecular atlas of Xenopus respiratory system development, focusing on Nkx2.1+ respiratory cell fate specification in the developing foregut. We document the expression patterns of Wnt/β-catenin, fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) signaling components in the foregut and show that the molecular mechanisms of respiratory lineage induction are remarkably conserved between Xenopus and mice. Finally, using several functional experiments we refine the epistatic relationships among FGF, Wnt, and BMP signaling in early Xenopus respiratory system development. We demonstrate that Xenopus trachea and lung development, before metamorphosis, is comparable at the cellular and molecular levels to embryonic stages of mouse respiratory system development between embryonic days 8.5 and 10.5. This molecular atlas provides a fundamental starting point for further studies using Xenopus as a model to define the conserved genetic programs controlling early respiratory system development. © 2014 Wiley Periodicals, Inc.

Respiratory virus transmission dynamics determine timing of asthma exacerbation peaks: Evidence from a population-level model.

PubMed

Eggo, Rosalind M; Scott, James G; Galvani, Alison P; Meyers, Lauren Ancel

2016-02-23

Asthma exacerbations exhibit a consistent annual pattern, closely mirroring the school calendar. Although respiratory viruses--the "common cold" viruses--are implicated as a principal cause, there is little evidence to link viral prevalence to seasonal differences in risk. We jointly fit a common cold transmission model and a model of biological and environmental exacerbation triggers to estimate effects on hospitalization risk. Asthma hospitalization rate, influenza prevalence, and air quality measures are available, but common cold circulation is not; therefore, we generate estimates of viral prevalence using a transmission model. Our deterministic multivirus transmission model includes transmission rates that vary when school is closed. We jointly fit the two models to 7 y of daily asthma hospitalizations in adults and children (66,000 events) in eight metropolitan areas. For children, we find that daily viral prevalence is the strongest predictor of asthma hospitalizations, with transmission reduced by 45% (95% credible interval =41-49%) during school closures. We detect a transient period of nonspecific immunity between infections lasting 19 (17-21) d. For adults, hospitalizations are more variable, with influenza driving wintertime peaks. Neither particulate matter nor ozone was an important predictor, perhaps because of the large geographic area of the populations. The school calendar clearly and predictably drives seasonal variation in common cold prevalence, which results in the "back-to-school" asthma exacerbation pattern seen in children and indirectly contributes to exacerbation risk in adults. This study provides a framework for anticipating the seasonal dynamics of common colds and the associated risks for asthmatics.

Cough aerosol in healthy participants: fundamental knowledge to optimize droplet-spread infectious respiratory disease management

PubMed Central

2012-01-01

Background The Influenza A H1N1 virus can be transmitted via direct, indirect, and airborne route to non-infected subjects when an infected patient coughs, which expels a number of different sized droplets to the surrounding environment as an aerosol. The objective of the current study was to characterize the human cough aerosol pattern with the aim of developing a standard human cough bioaerosol model for Influenza Pandemic control. Method 45 healthy non-smokers participated in the open bench study by giving their best effort cough. A laser diffraction system was used to obtain accurate, time-dependent, quantitative measurements of the size and number of droplets expelled by the cough aerosol. Results Voluntary coughs generated droplets ranging from 0.1 - 900 microns in size. Droplets of less than one-micron size represent 97% of the total number of measured droplets contained in the cough aerosol. Age, sex, weight, height and corporal mass have no statistically significant effect on the aerosol composition in terms of size and number of droplets. Conclusions We have developed a standard human cough aerosol model. We have quantitatively characterized the pattern, size, and number of droplets present in the most important mode of person-to-person transmission of IRD: the cough bioaerosol. Small size droplets (< 1 μm) predominated the total number of droplets expelled when coughing. The cough aerosol is the single source of direct, indirect and/or airborne transmission of respiratory infections like the Influenza A H1N1 virus. Study design Open bench, Observational, Cough, Aerosol study PMID:22436202

Simple and Inexpensive but Highly Discriminating Method for Computer-Assisted DNA Fingerprinting of Pseudomonas aeruginosa

PubMed Central

Al-Samarrai, Taha H.; Zhang, Ningxin; Lamont, Iain L.; Martin, Lois; Kolbe, John; Wilsher, Margaret; Morris, Arthur J.; Schmid, Jan

2000-01-01

We describe here a method for computer-assisted fingerprinting of Pseudomonas aeruginosa. In this method, DNA is digested with SalI, and bands with molecular sizes of ≥9.7 kb are visually scored after electrophoresis on agarose gels. Pattern scores are entered into a Microsoft Excel database. In scoring, the number of bands within each of a set of molecular size ranges is scored, rather than the absolute molecular size of each band, substantially enhancing the speed and reproducibility of the method, while eliminating the need for using expensive gel scanning equipment and software. Pattern scores are used to generate matrices of genetic distance values, which can be visualized in neighbor-joining trees. The method reliably distinguishes two epidemiologically unrelated isolates in 99.3% of all comparisons. The genetic relationships between isolates observed with the method were consistent with those obtained by analysis of two P. aeruginosa genes, indicating that it provides valid estimates of genetic divergence between isolates. Using the method, respiratory tract isolates from cystic fibrosis patients in Green Lane Hospital in Auckland, New Zealand, were shown to be genetically less diverse than epidemiologically unrelated isolates from other patients. This finding was not due to the existence of clusters of related strains specialized toward colonization of the respiratory tract and thus was indicative of transmission between patients. Analysis of multiple isolates from individual cystic fibrosis patients suggested that up to five separate clusters of genetically related strains may simultaneously be present in a patient. The method described should significantly enhance our ability to investigate the epidemiology of P. aeruginosa. PMID:11101578

Respiratory virus transmission dynamics determine timing of asthma exacerbation peaks: Evidence from a population-level model

PubMed Central

Scott, James G.; Galvani, Alison P.; Meyers, Lauren Ancel

2016-01-01

Asthma exacerbations exhibit a consistent annual pattern, closely mirroring the school calendar. Although respiratory viruses—the “common cold” viruses—are implicated as a principal cause, there is little evidence to link viral prevalence to seasonal differences in risk. We jointly fit a common cold transmission model and a model of biological and environmental exacerbation triggers to estimate effects on hospitalization risk. Asthma hospitalization rate, influenza prevalence, and air quality measures are available, but common cold circulation is not; therefore, we generate estimates of viral prevalence using a transmission model. Our deterministic multivirus transmission model includes transmission rates that vary when school is closed. We jointly fit the two models to 7 y of daily asthma hospitalizations in adults and children (66,000 events) in eight metropolitan areas. For children, we find that daily viral prevalence is the strongest predictor of asthma hospitalizations, with transmission reduced by 45% (95% credible interval =41–49%) during school closures. We detect a transient period of nonspecific immunity between infections lasting 19 (17–21) d. For adults, hospitalizations are more variable, with influenza driving wintertime peaks. Neither particulate matter nor ozone was an important predictor, perhaps because of the large geographic area of the populations. The school calendar clearly and predictably drives seasonal variation in common cold prevalence, which results in the “back-to-school” asthma exacerbation pattern seen in children and indirectly contributes to exacerbation risk in adults. This study provides a framework for anticipating the seasonal dynamics of common colds and the associated risks for asthmatics. PMID:26858436

Cough aerosol in healthy participants: fundamental knowledge to optimize droplet-spread infectious respiratory disease management.

PubMed

Zayas, Gustavo; Chiang, Ming C; Wong, Eric; MacDonald, Fred; Lange, Carlos F; Senthilselvan, Ambikaipakan; King, Malcolm

2012-03-21

The Influenza A H1N1 virus can be transmitted via direct, indirect, and airborne route to non-infected subjects when an infected patient coughs, which expels a number of different sized droplets to the surrounding environment as an aerosol. The objective of the current study was to characterize the human cough aerosol pattern with the aim of developing a standard human cough bioaerosol model for Influenza Pandemic control. 45 healthy non-smokers participated in the open bench study by giving their best effort cough. A laser diffraction system was used to obtain accurate, time-dependent, quantitative measurements of the size and number of droplets expelled by the cough aerosol. Voluntary coughs generated droplets ranging from 0.1 - 900 microns in size. Droplets of less than one-micron size represent 97% of the total number of measured droplets contained in the cough aerosol. Age, sex, weight, height and corporal mass have no statistically significant effect on the aerosol composition in terms of size and number of droplets. We have developed a standard human cough aerosol model. We have quantitatively characterized the pattern, size, and number of droplets present in the most important mode of person-to-person transmission of IRD: the cough bioaerosol. Small size droplets (< 1 μm) predominated the total number of droplets expelled when coughing. The cough aerosol is the single source of direct, indirect and/or airborne transmission of respiratory infections like the Influenza A H1N1 virus. Open bench, Observational, Cough, Aerosol study. © 2012 Zayas et al; licensee BioMed Central Ltd.

Comparative Computational Modeling of Airflows and Vapor Dosimetry in the Respiratory Tracts of Rat, Monkey, and Human

PubMed Central

Corley, Richard A.

2012-01-01

Computational fluid dynamics (CFD) models are useful for predicting site-specific dosimetry of airborne materials in the respiratory tract and elucidating the importance of species differences in anatomy, physiology, and breathing patterns. We improved the imaging and model development methods to the point where CFD models for the rat, monkey, and human now encompass airways from the nose or mouth to the lung. A total of 1272, 2172, and 135 pulmonary airways representing 17±7, 19±9, or 9±2 airway generations were included in the rat, monkey and human models, respectively. A CFD/physiologically based pharmacokinetic model previously developed for acrolein was adapted for these anatomically correct extended airway models. Model parameters were obtained from the literature or measured directly. Airflow and acrolein uptake patterns were determined under steady-state inhalation conditions to provide direct comparisons with prior data and nasal-only simulations. Results confirmed that regional uptake was sensitive to airway geometry, airflow rates, acrolein concentrations, air:tissue partition coefficients, tissue thickness, and the maximum rate of metabolism. Nasal extraction efficiencies were predicted to be greatest in the rat, followed by the monkey, and then the human. For both nasal and oral breathing modes in humans, higher uptake rates were predicted for lower tracheobronchial tissues than either the rat or monkey. These extended airway models provide a unique foundation for comparing material transport and site-specific tissue uptake across a significantly greater range of conducting airways in the rat, monkey, and human than prior CFD models. PMID:22584687

The movement and deposition of PM2.5 in the upper respiratory tract for the patients with heart failure: an elementary CFD study.

PubMed

Zhang, Tiantian; Gao, Bin; Zhou, Zhixiang; Chang, Yu

2016-12-28

PM2.5 is an important factor to affect the patients with respiratory and cardiovascular diseases. Clinical studies have found that the morbidity and mortality of patients with heart failure (HF) have a close relationship with the movement and deposition state of PM2.5. One reason is that the breathing pattern of patients with HF has obvious difference with healthy people, however the effect caused by these differences on the distribution regularity of PM2.5 in the respiratory tract is still unclear. Hence, a computational fluid dynamics simulation was conducted to clarify the aerodynamic effect of breathing pattern of patients with HF on respiratory system. Ideal upper respiratory tract geometric model was established based on standardized aerosol research laboratory of Alberta and Weibel A dimension. The discrete phase method is used to calculate the movement of the airflow and particles. The flow rate were chosen as the inlet boundary conditions, and the outlets are set at a constant pressure. The rate of particle deposition, distribution location, wall pressure, flow velocity and wall shear stress are obtained, and compared to the normal control. The results demonstrated that the rate of escaped particles in every bronchial outlet of the patients with HF was more than the normal controls, meanwhile the trapped was less (1024 < 1160). There was higher by 12.9% possibility that the PM2.5 entered the lungs than the normal control. The aerodynamic performances of HF patients are different from normal control. Compared to the normal control, under similar environment, there is higher possibility of PM2.5 moving into lungs, and these particles could affect the function of the respiratory system, resulting in the deterioration of the state of cardiovascular system. In short, it's necessary to pay more attention to the living environment of HF patients, to reduce the content of PM2.5 particles in the air, and reduce the damage of PM2.5 particles caused by breathing patterns.

Efficiency index: a new parameter to define breathing patterns during dynamic Xe-127 ventilation studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slosman, D.; Susskind, H.; Bossuyt, A.

1986-03-01

Ventilation imaging can be improved by gating scintigraphic data with the respiratory cycle using temporal Fourier analysis (TFA) to quantify the temporal behavior of the ventilation. Sixteen consecutive images, representing equal-time increments of an average respiratory cycle, were produced by TFA in the posterior view on a pixel-by-pixel basis. An Efficiency Index (EFF), defined as the ratio of the summation of all the differences between maximum and minimum counts for each pixel to that for the entire lung during the respiratory cycle, was derived to describe the pattern of ventilation. The gated ventilation studies were carried out with Xe-127 inmore » 12 subjects: normal lung function (4), small airway disease (2), COPD (5), and restrictive disease (1). EFF for the first three harmonics correlated linearly with FEV1 (r = 0.701, p< 0.01). This approach is suggested as a very sensitive method to quantify the extent and regional distribution of airway obstruction.« less

Rett syndrome: stimulation of endogenous biogenic amines.

PubMed

Pelligra, R; Norton, R D; Wilkinson, R; Leon, H A; Matson, W R

1992-06-01

Transient hypercapnic hyperoxemia was induced in two Rett syndrome children by the administration of a gaseous mixture of 80% O2 and 20% CO2. Time course studies of neurotransmitters and their metabolites showed an immediate and marked increase in central biogenic amine turnover following inhalation of the gas mixture. The increased turnover of biogenic amines was associated with improved clinical changes. This suggests a coupled relationship and provides further support for an etiological role of neurotransmitter dysfunction in Rett syndrome. In a complementary study, elevation of pulmonary CO2 by application of a simple rebreathing device resulted in improvement of abnormal blood gases and elimination of the Cheyne-Stokes-like respiratory pattern of the Rett syndrome. Near normalization of the EEG occurred when a normal respiratory pattern was imposed by means of a respirator. Taken together, these results lead to the preliminary conclusion that cerebral hypoxemia secondary to abnormal respiratory function may contribute to diminished production of biogenic amines in Rett syndrome.

Neurotoxicity in Snakebite—The Limits of Our Knowledge

PubMed Central

Ranawaka, Udaya K.; Lalloo, David G.; de Silva, H. Janaka

2013-01-01

Snakebite is classified by the WHO as a neglected tropical disease. Envenoming is a significant public health problem in tropical and subtropical regions. Neurotoxicity is a key feature of some envenomings, and there are many unanswered questions regarding this manifestation. Acute neuromuscular weakness with respiratory involvement is the most clinically important neurotoxic effect. Data is limited on the many other acute neurotoxic manifestations, and especially delayed neurotoxicity. Symptom evolution and recovery, patterns of weakness, respiratory involvement, and response to antivenom and acetyl cholinesterase inhibitors are variable, and seem to depend on the snake species, type of neurotoxicity, and geographical variations. Recent data have challenged the traditional concepts of neurotoxicity in snake envenoming, and highlight the rich diversity of snake neurotoxins. A uniform system of classification of the pattern of neuromuscular weakness and models for predicting type of toxicity and development of respiratory weakness are still lacking, and would greatly aid clinical decision making and future research. This review attempts to update the reader on the current state of knowledge regarding this important issue. PMID:24130909

Rett syndrome - Stimulation of endogenous biogenic amines

NASA Technical Reports Server (NTRS)

Pelligra, R.; Norton, R. D.; Wilkinson, R.; Leon, H. A.; Matson, W. R.

1992-01-01

Transient hypercapnic hyperoxemia was induced in two Rett syndrome children by the administration of a gaseous mixture of 80 percent O2 and 20 percent CO2. Time course studies of neurotransmitters and their metabolites showed an immediate and marked increase in central biogenic amine turnover following inhalation of the gas mixture. The increased turnover of biogenic amines was associated with improved clinical changes. This suggests a coupled relationship and provides further support for an etiological role of neurotransmitter dysfunction in Rett syndrome. In a complementary study, elevation of pulmonary CO2 by application of a simple rebreathing device resulted in improvement of abnormal blood gases and elimination of the Cheyne-Stokes-like respiratory pattern of the Rett syndrome. Near normalization of the EEG occurred when a normal respiratory pattern was imposed by means of a respirator. Taken together, these results lead to the preliminary conclusion that cerebral hypoxemia secondary to abnormal respiratory function may contribute to diminished production of biogenic amines in Rett syndrome.

Analyzing non-respiratory movements of the chest: methods and devices

NASA Astrophysics Data System (ADS)

Pariaszewska, Katarzyna; Młyńczak, Marcel; Cybulski, Gerard

2015-09-01

Respiration is the main reason of the chest movements. However, there are also non-respiratory ones, resulting from e.g. snoring, wheezing, stridor, throat clearing or coughing. They may exist sporadically, however should be examined in case when their incidences increase. Detecting non-respiratory movements is very important, because many of them are symptoms of respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD) or lung cancer. Assessment of the presence of non-respiratory movements could be important element of effective diagnosis. It is also necessary to provide quantitative and objective results for intra-subject studies. Most of these events generate vibroacoustic signals that contain components of sound and vibrations. This work provides the review of the solutions and devices for monitoring of the non-respiratory movements, primarily considering the accuracy of the chest movements' detection and distinguishing.

Modification of medullary respiratory-related discharge patterns by behaviors and states of arousal.

PubMed

Chang, F C

1992-02-07

The modulatory influences of behaviors and states of arousal on bulbar respiratory-related unit (RRU) discharge patterns were studied in an unanesthetized, freely behaving guinea pig respiratory model system. When fully instrumented, this model system permits concurrent monitoring and recording of (i) single units from either Bötzinger complex or nucleus para-ambiguus; (ii) electrocorticogram; and, (iii) diaphragmatic EMG. In addition to being used in surveys of RRU discharge patterns in freely behaving states, the model system also offered a unique opportunity in investigating the effects of pentobarbital on RRU discharge patterns before, throughout the course of, and during recovery from anesthesia. In anesthetized preparations, a particular RRU discharge pattern (such as tonic, incrementing or decrementing) typically displayed little, if any notable variation. The most striking development following pentobarbital was a state of progressive bradypnea attributable to a significantly augmented RRU cycle duration, burst duration and an increase in the RRU spike frequencies during anesthesia. In freely behaving states, medullary RRU activities rarely adhered to a fixed, immutable discharge pattern. More specifically, the temporal organization (such as burst duration, cycle duration, and the extent of modulation of within-burst spike frequencies) of RRU discharge patterns regularly showed complex and striking variations, not only with states of arousal (sleep/wakefulness, anesthesia) but also with discrete alterations in electrocorticogram (ECoG) activities and a multitude of on-going behavioral repertoires such as volitional movement, postural modification, phonation, mastication, deglutition, sniffing/exploratory behavior, alerting/startle reflexes. Only during sleep, and on occasions when the animal assumed a motionless, resting posture, could burst patterns of relatively invariable periodicity and uniform temporal attributes be observed. RRU activities during sniffing reflex is worthy of further note in that, based on power spectrum analyses of concurrently recorded ECoG activities, this particular discharge pattern was clearly associated with the activation of a 6-10 Hz theta rhythm. These findings indicated that bulbar RRU activity patterns are subject to change by not only behaviors and sleep/wakefulness cycles, but also a variety of modulatory influences and feedback/feedforward biases from other central and peripheral physiological control mechanisms.

Phylogenetic trends in respiratory rhythmogenesis: insights from ectothermic vertebrates.

PubMed

Kinkead, Richard

2009-08-31

Understanding the neural substrate driving breathing has puzzled physiologists for more than a century. The discovery of the pre-Bötzinger complex (preBötC) in newborn rodents as a structure with a unique physiological function in respiratory rhythm generation was an important progress in respiratory neurobiology that stimulated much research. Owing to the extensive literature describing the location, organisation, and function of the preBötC mainly in newborn rodents, this structure has become the point of reference in studies addressing respiratory rhythm generation in other mammals and various classes of vertebrates. This paper reviews recent progress made in non-mammalian vertebrates in our understanding of the location and function of the neural networks driving respiratory activity. As in newborn rodents, data from lampreys, air breathing fish, and amphibians show that the production of eupnea is the result of interactions between multiple (at least two) rhythmogenic networks. These networks are located in anatomically distinct areas and show different functional properties in terms of their ability to produce (or not) bursting activity in the absence of synaptic inputs (e.g. pacemaker neurons) and their sensitivity to specific neuromodulators such as substance P, somatostatin, and opioids. Current data indicate that respiratory rhythmogenesis is a phylogenetically ancient function that was highly conserved throughout evolution and that a comparative approach remains important to derive broader biological principles and a more comprehensive view.

The Effects of Electronic Cigarette (ECIG)-Generated Aerosol and Conventional Cigarette Smoke on the Mucociliary Transport Velocity (MTV) Using the Bullfrog (R. catesbiana) Palate Paradigm

PubMed Central

Palazzolo, Dominic L.; Nelson, John M.; Ely, Emily A.; Crow, Andrew P.; Distin, James; Kunigelis, Stan C.

2017-01-01

Background: While ECIGs are under scrutiny concerning safety, particularly in reference to the physiological impact that aerosolized ECIG liquid (E-liquid) may have on respiratory tissues, others believe that ECIGs are a “Harm Reduction” alternative to conventional cigarettes. Previous studies investigating ciliated respiratory epithelium indicate that smoking shortens cilia length, reduces cilia beat frequency and disrupts respiratory epithelium, which most likely contributes to the inhibition of mucocilliary clearance. Monitoring mucous clearance of respiratory tissues exposed to ECIG-generated aerosol or conventional cigarette smoke, as indexed by mucous transport velocity (MTV), is one way to gauge the impact aerosol and smoke have on the respiratory tract. Therefore, we designed an experiment to test the effect of ECIG-generated aerosol and smoke on MTV using the frog palate paradigm. Methods: Peristaltic pumps transport ECIG-generated aerosol and conventional cigarette smoke into custom-made chambers containing excised bullfrog palates. MTVs were determined before exposure, immediately after exposure and approximately 1 day following exposure. MTVs were also determined (at the same time points) for palates exposed to air (control). Surface and cross sectional SEM images of palates from all three groups were obtained to support MTV data. Results: The results indicate that ECIG-generated aerosol has a modest inhibitory effect (p < 0.05) on MTV 1 day post-exposure (0.09 ± 0.01) compared to control MTV (0.16 ± 0.03 mm/s). In contrast, smoke completely inhibits MTV from 0.14 ± 0.03 mm/s immediately before exposure to 0.00 mm/sec immediately after exposure and the MTV is unable to recover 1 day later. SEM images of control palates and palates exposed to ECIG-generated aerosol both show cilia throughout their epithelial surface, while some areas of palates exposed to smoke are completely devoid of cilia. Additionally, the epithelial thickness of aerosol-exposed palates appears thicker than control palates while smoke-exposed palates appear to be thinner due to epithelial disruption. Conclusions: These results indicate that ECIG-generated aerosol has only a modest effect on mucocilary clearance of bullfrog palates and aerosol sedimentation accounts for epithelial thickening. In accordance with the primary literature, conventional cigarette smoke dramatically inhibits mucociliary clearance and is, in part, due to decreased number of cilia and disruption of the smoke-exposed epithelium. PMID:29321743

Smoking-related interstitial lung diseases.

PubMed

Caminati, A; Graziano, P; Sverzellati, N; Harari, S

2010-12-01

In pulmonary pathology, a wide spectrum of morphological changes is related to the consequences of smoking, and recognizing them on surgical specimens and on small transbronchial biopsies represents a challenge for the pathologist. Respiratory bronchiolitis, also referred to as smoker's bronchiolitis, is a common histologic feature found in the lung tissue of cigarette smokers. When identified as the sole histopathologic finding in the clinical setting of symptomatic interstitial lung disease, a diagnosis of respiratory bronchiolitis-interstitial lung disease is made. Since smoking is recognized to cause a variety of histologic patterns encompassing respiratory bronchiolitis, respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia and pulmonary Langerhans cell hystiocytosis, smoking-related interstitial lung disease may be a useful concept to keep in mind for the pathologists. The relationship of smoking with each of these entities has been largely established on the basis of epidemiologic evidence. Although they have been retained as distinct and separate conditions in various classifications of interstitial lung diseases, these entities share a number of clinical, radiologic, and pathologic features suggesting that they represent a spectrum of patterns of interstitial lung disease occurring in predisposed individuals who smoke. Evaluation of histologic features, particularly in surgical lung biopsy samples, is important in making the distinction between these disorders. However, even after tissue biopsy, it may sometimes be difficult to clearly separate these entities. Recently, respiratory bronchiolitis-interstitial lung disease with fibrosis has been described and postulated that this is a smoking-related condition distinct from fibrotic non-specific interstitial pneumonia.

Air pollution and cardiovascular and respiratory emergency visits in Central Arkansas: A time-series analysis.

PubMed

Rodopoulou, Sophia; Samoli, Evangelia; Chalbot, Marie-Cecile G; Kavouras, Ilias G

2015-12-01

Heart disease and stroke mortality and morbidity rates in Arkansas are among the highest in the U.S. While the effect of air pollution on cardiovascular health was identified in traffic-dominated metropolitan areas, there is a lack of studies for populations with variable exposure profiles, demographic and disease characteristics. Determine the short-term effects of air pollution on cardiovascular and respiratory morbidity in the stroke and heart failure belt. We investigated the associations of fine particles and ozone with respiratory and cardiovascular emergency room visits during the 2002-2012 period for adults in Central Arkansas using Poisson generalized models adjusted for temporal, seasonal and meteorological effects. We evaluated sensitivity of the associations to mutual pollutant adjustment and effect modification patterns by sex, age, race and season. We found effects on cardiovascular and respiratory emergencies for PM2.5 (1.52% [95% (confidence interval) CI: -1.10%, 4.20%]; 1.45% [95%CI: -2.64%, 5.72%] per 10 μg/m3) and O3 (0.93% [95%CI: -0.87%, 2.76%]; 0.76 [95%CI: -1.92%, 3.52%] per 10 ppbv) during the cold period (October-March). The effects were stronger among whites, except for the respiratory effects of O3 that were higher among Blacks/African-Americans. Effect modification patterns by age and sex differed by association. Both pollutants were associated with increases in emergency room visits for hypertension, heart failure and asthma. Effects on cardiovascular and respiratory emergencies were observed during the cold period when particulate matter was dominated by secondary nitrate and wood burning. Outdoor particulate pollution during winter had an effect on cardiovascular morbidity in central Arkansas, the region with high stroke and heart disease incidence rates. Copyright © 2015 Elsevier B.V. All rights reserved.

Human respiratory syncytial virus in children with lower respiratory tract infections or influenza-like illness and its co-infection characteristics with viruses and atypical bacteria in Hangzhou, China.

PubMed

Yu, Xinfen; Kou, Yu; Xia, Daozong; Li, Jun; Yang, Xuhui; Zhou, Yinyan; He, Xiaoyan

2015-08-01

Human respiratory syncytial virus (RSV) is the most important viral pathogen in children. However, its epidemic patterns and co-infection characteristics are not fully understood. We attempted to determine the level of genetic variation of RSV, and describe the prevalence and co-infection characteristics of RSV in Hangzhou during two epidemic seasons. Single respiratory samples from 1820 pediatric patients were screened for RSV and genotyped by RT-PCR and sequencing. In all RSV positive specimens, we screened for viruses and atypical bacteria. Demographic and clinical information was recorded and analyzed. A total of 34.5% and 3.8% of samples from acute lower respiratory tract infections (ALRI) and influenza-like illness (ILI) were positive for RSV, respectively. Phylogenetic analysis revealed that 61.1% of the selected 167 RSV strains were NA1, 31.1% were BA, 3.6% were ON1, 2.4% were CB1, and 1.8% were NA3. A new genotype, BA11 was identified, which comprised 98.1% of BA strains in this study, while the rest were BA10. A total of 36.4% and 9.1% of RSV-positive children with ALRI and ILI respectively were found to be co-infected. Rhinovirus was the most common additional respiratory virus, followed by human metapneumovirus. Except for fever, no significant differences in other clinical presentation between the RSV mono-infection and co-infection groups were observed. The circulating RSV strains had high genetic variability with RSV-B showing a more local pattern. In ALRI cases, co-infection of RSV with other viruses or atypical bacteria has no significant effect on the clinical presentation except fever. Copyright © 2015 Elsevier B.V. All rights reserved.

Numerical simulation of two consecutive nasal respiratory cycles: toward a better understanding of nasal physiology.

PubMed

de Gabory, Ludovic; Reville, Nicolas; Baux, Yannick; Boisson, Nicolas; Bordenave, Laurence

2018-01-16

Computational fluid dynamic (CFD) simulations have greatly improved the understanding of nasal physiology. We postulate that simulating the entire and repeated respiratory nasal cycles, within the whole sinonasal cavities, is mandatory to gather more accurate observations and better understand airflow patterns. A 3-dimensional (3D) sinonasal model was constructed from a healthy adult computed tomography (CT) scan which discretized in 6.6 million cells (mean volume, 0.008 mm 3 ). CFD simulations were performed with ANSYS©FluentTMv16.0.0 software with transient and turbulent airflow (k-ω model). Two respiratory cycles (8 seconds) were simulated to assess pressure, velocity, wall shear stress, and particle residence time. The pressure gradients within the sinus cavities varied according to their place of connection to the main passage. Alternations in pressure gradients induced a slight pumping phenomenon close to the ostia but no movement of air was observed within the sinus cavities. Strong movements were observed within the inferior meatus during expiration contrary to the inspiration, as in the olfactory cleft at the same time. Particle residence time was longer during expiration than inspiration due to nasal valve resistance, as if the expiratory phase was preparing the next inspiratory phase. Throughout expiration, some particles remained in contact with the lower turbinates. The posterior part of the olfactory cleft was gradually filled with particles that did not leave the nose at the next respiratory cycle. This pattern increased as the respiratory cycle was repeated. CFD is more efficient and reliable when the entire respiratory cycle is simulated and repeated to avoid losing information. © 2018 ARS-AAOA, LLC.

Occurrence of respiratory symptoms in persons with restrictive ventilatory impairment compared with persons with chronic obstructive pulmonary disease: The PLATINO study.

PubMed

Nonato, Nívia L; Nascimento, Oliver A; Padilla, Rogelio P; de Oca, Maria M; Tálamo, Carlos; Valdivia, Gonzalo; Lisboa, Carmen; López, Maria V; Celli, Bartolomé; Menezes, Ana Maria B; Jardim, José R

2015-08-01

Patients with chronic obstructive pulmonary disease (COPD) usually complain of symptoms such as cough, sputum, wheezing, and dyspnea. Little is known about clinical symptoms in individuals with restrictive ventilatory impairment. The aim of this study was to compare the prevalence and type of respiratory symptoms in patients with COPD to those reported by individuals with restrictive ventilatory impairment in the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar study. Between 2002 and 2004, individuals ≥40 years of age from five cities in Latin America performed pre and post-bronchodilator spirometry and had their respiratory symptoms recorded in a standardized questionnaire. Among the 5315 individuals evaluated, 260 (5.1%) had a restrictive spirometric diagnosis (forced vital capacity (FVC) < lower limit of normal (LLN) with forced expiratory volume in the first second to forced vital capacity ratio (FEV1/FVC) ≥ LLN; American Thoracic Society (ATS)/European Respiratory Society (ERS) 2005) and 610 (11.9%) were diagnosed with an obstructive pattern (FEV1/FVC < LLN; ATS/ERS 2005). Patients with mild restriction wheezed more ((30.8%) vs. (17.8%); p < 0.028). No difference was seen in dyspnea, cough, and sputum between the two groups after adjusting for severity stage. The health status scores for the short form 12 questionnaire were similar in restricted and obstructed patients for both physical (48.4 ± 9.4 vs. 48.3 ± 9.8) and mental (50.8 ± 10.6 vs. 50.0 ± 11.5) domains. Overall, respiratory symptoms are not frequently reported by patients with restricted and obstructed patterns as defined by spirometry. Wheezing was more frequent in patients with restricted pattern compared with those with obstructive ventilatory defect. However, the prevalence of cough, sputum production, and dyspnea are not different between the two groups when adjusted by the same severity stage. © The Author(s) 2015.

Low breast milk levels of long-chain n-3 fatty acids in allergic women, despite frequent fish intake.

PubMed

Johansson, S; Wold, A E; Sandberg, A-S

2011-04-01

Long-chain n-3 polyunsaturated fatty acids (PUFAs) have immune regulating and anti-inflammatory effects. However, their role in allergic disease is unclear. Allergic diseases are immunologically heterogeneous, and we hypothesized that n-3 fatty acid composition in serum and breast milk may vary according to clinical manifestations. Further, animal studies have shown reduction of serum-PUFA levels during allergic inflammation. To investigate fatty acid composition in breast milk and serum from women with different atopic disease manifestations. Secondly, to determine whether low PUFA levels reflected insufficient intakes. Fatty acids were analysed in breast milk and serum of women with atopic eczema and respiratory allergy (n=16), only respiratory allergy (n=7), as well as healthy women (n=22). Dietary intake of foods expected to affect long-chain n-3 PUFA levels were estimated by food-frequency questionnaire. The fatty acid pattern was related to diagnostic group and intake of relevant food items using a multivariate pattern recognition method (partial least squares projections to latent structures and discriminant analysis). Results Women with a combination of eczema and respiratory allergy had lower breast milk levels of several PUFAs (arachidonic acid, eicosapentaenoic acid, EPA, docosahexaenoic acid, DHA, and docosapentaenoic acid, DPA), and a lower ratio of long-chain n-3 PUFAs/n-6 PUFAs. Their PUFA levels differed not only from that of healthy women, but also from that of women with only respiratory allergy. The latter had a fatty acid pattern similar to that of healthy women. Despite low EPA, DHA and DPA levels women with eczema and respiratory allergy consumed no less fish than did healthy women. Our data suggest that reduced levels of long-chain n-3 fatty acids in serum and breast milk characterize women with extensive allergic disease including eczema, and are not related to low fish intake. Consumption of PUFAs during the allergic process may explain these findings. © 2011 Blackwell Publishing Ltd.

Morbidity Forecast in Cities: A Study of Urban Air Pollution and Respiratory Diseases in the Metropolitan Region of Curitiba, Brazil.

PubMed

de Souza, Fabio Teodoro

2018-05-29

In the last two decades, urbanization has intensified, and in Brazil, about 90% of the population now lives in urban centers. Atmospheric patterns have changed owing to the high growth rate of cities, with negative consequences for public health. This research aims to elucidate the spatial patterns of air pollution and respiratory diseases. A data-based model to aid local urban management to improve public health policies concerning air pollution is described. An example of data preparation and multivariate analysis with inventories from different cities in the Metropolitan Region of Curitiba was studied. A predictive model with outstanding accuracy in prediction of outbreaks was developed. Preliminary results describe relevant relations among morbidity scales, air pollution levels, and atmospheric seasonal patterns. The knowledge gathered here contributes to the debate on social issues and public policies. Moreover, the results of this smaller scale study can be extended to megacities.

Hypoxemia, hypercapnia, and breathing pattern in patients with chronic obstructive pulmonary disease.

PubMed

Parot, S; Miara, B; Milic-Emili, J; Gautier, H

1982-11-01

The results of lung function tests (total and functional residual capacities, residual volume/total lung capacity ratio, forced expiratory volume in one second) breathing patterns and arterial PO2 and PCO2 were studied in 651 ambulatory male patients with chronic obstructive pulmonary disease, functionally and clinically stable. Function tests were only loosely correlated with gas tensions: abnormalities in mechanics and in gas exchange are not necessarily related. In patients matched for the degree of obstruction, the breathing pattern depended upon both PaO2 and PaCO2. Isolated hypoxemia was accompanied by increased respiratory frequency without any variation in tidal volume: this suggests that the chemoreceptive systems still responded to changes in PaO2. Isolated hypercapnia was accompanied by a decrease in tidal volume and an increase in respiratory frequency. Consequently, the dead space/tidal volume ratio increased, leading to a drop in alveolar ventilation and to CO2 retention.

21 CFR 868.5440 - Portable oxygen generator.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Portable oxygen generator. 868.5440 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5440 Portable oxygen generator. (a) Identification. A portable oxygen generator is a device that is intended to release oxygen for respiratory...

21 CFR 868.5440 - Portable oxygen generator.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Portable oxygen generator. 868.5440 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5440 Portable oxygen generator. (a) Identification. A portable oxygen generator is a device that is intended to release oxygen for respiratory...

21 CFR 868.5440 - Portable oxygen generator.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Portable oxygen generator. 868.5440 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5440 Portable oxygen generator. (a) Identification. A portable oxygen generator is a device that is intended to release oxygen for respiratory...

21 CFR 868.5440 - Portable oxygen generator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Portable oxygen generator. 868.5440 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5440 Portable oxygen generator. (a) Identification. A portable oxygen generator is a device that is intended to release oxygen for respiratory...

21 CFR 868.5440 - Portable oxygen generator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Portable oxygen generator. 868.5440 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5440 Portable oxygen generator. (a) Identification. A portable oxygen generator is a device that is intended to release oxygen for respiratory...

Assessing Modeled CO2 Retention and Rebreathing of a Facemask Designed for Efficient Delivery of Aerosols to Infants

PubMed Central

Mundt, Christian; Sventitskiy, Alexander; Cehelsky, Jeffrey E.; Patters, Andrea B.; Tservistas, Markus; Hahn, Michael C.; Juhl, Gerd; DeVincenzo, John P.

2012-01-01

Background. New aerosol drugs for infants may require more efficient delivery systems, including face masks. Maximizing delivery efficiency requires tight-fitting masks with minimal internal mask volumes, which could cause carbon dioxide (CO2) retention. An RNA-interference-based antiviral for treatment of respiratory syncytial virus in populations that may include young children is designed for aerosol administration. CO2 accumulation within inhalation face masks has not been evaluated. Methods. We simulated airflow and CO2 concentrations accumulating over time within a new facemask designed for infants and young children (PARI SMARTMASK® Baby). A one-dimensional model was first examined, followed by 3-dimensional unsteady computational fluid dynamics analyses. Normal infant breathing patterns and respiratory distress were simulated. Results. The maximum average modeled CO2 concentration within the mask reached steady state (3.2% and 3% for normal and distressed breathing patterns resp.) after approximately the 5th respiratory cycle. After steady state, the mean CO2 concentration inspired into the nostril was 2.24% and 2.26% for normal and distressed breathing patterns, respectively. Conclusion. The mask is predicted to cause minimal CO2 retention and rebreathing. Infants with normal and distressed breathing should tolerate the mask intermittently delivering aerosols over brief time frames. PMID:22792479

Antimicrobial multidrug resistance and coresistance patterns of Mannheimia haemolytica isolated from bovine respiratory disease cases--a three-year (2009-2011) retrospective analysis.

PubMed

Lubbers, Brian V; Hanzlicek, Gregg A

2013-05-01

Bovine respiratory disease continues to be the most important ailment of feed yard cattle. While the disease is multifactorial in nature, therapy continues to target the primary bacterial pathogens, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. A survey of records from a single diagnostic laboratory was conducted to evaluate the percentage of M. haemolytica isolates that were resistant to multiple antimicrobials and if coresistance patterns could be detected. All susceptibility test results for M. haemolytica recovered from lung tissues of cattle were eligible for inclusion in the survey. There were no isolates over the course of the analysis that were resistant to all 6 antimicrobials, primarily due to a lack of resistance to ceftiofur. In 2009, just over 5% of isolates were resistant to 5 or more antimicrobials (pan-resistant). In 2011, more than 35% of the M. haemolytica isolates were characterized as pan-resistant. Significant antimicrobial coresistance patterns were only seen with oxytetracycline and tilmicosin; bacterial isolates that were resistant to either oxytetracycline or tilmicosin were more likely to be resistant to at least one other antimicrobial. The mechanisms by which M. haemolytica is developing multidrug resistance warrant investigation if antimicrobial utility in the therapy of bovine respiratory disease is to be preserved.

Influence of drive and timing mechanisms on breathing pattern and ventilation during mental task performance.

PubMed

Wientjes, C J; Grossman, P; Gaillard, A W

1998-09-01

Assessment of multiple respiratory measures may provide insight into how behavioral demands affect the breathing pattern. This is illustrated by data from a study among 44 subjects, in which tidal volume, respiration rate, minute ventilation and indices of central drive and timing mechanisms were assessed via inductive plethysmography, in addition to end-tidal PCO2. After a baseline, three conditions of a memory comparison task were presented. The first two conditions differed only with regard to the presence or absence of feedback of performance (NFB and FB). In the third 'all-or-nothing' (AON) condition, subjects only received a monetary bonus, if their performance exceeded that of the previous two conditions. Minute ventilation increased from baseline to all task conditions, and from NFB and FB to AON. Respiration rate increased in all task conditions, but there were no differences between task conditions. Tidal volume decreased during NFB, but was equal to baseline during FB and AON. Of the respiratory control indices, inspiratory flow rate covaried much more closely with minute ventilation than duty cycle. The task performance induced a minor degree of hyperventilation. The discussion focusses on how behavioral demands affect respiratory control processes to produce alterations in breathing pattern and ventilation.

Prescribing Patterns of Drugs in Acute Respiratory Distress Syndrome (ARDS): An Observational Study

PubMed Central

Rao, Shobitha; Chogtu, Bharti

2015-01-01

Introduction: Acute respiratory distress syndrome (ARDS) is characterized by acute respiratory failure and is associated with wide range of clinical disorders. Controversy prevails over the pharmacological intervention in this disease. The aim of the study was to observe the prescribing pattern of drugs in patients with ARDS managed at a tertiary care hospital. Materials and Methods: This observational study was conducted at tertiary care hospital in India. Data of patients admitted from January 2010 to December 2012 was collected. Patients aged more than 18 years admitted in ICU, who were diagnosed to have ARDS during the study period, were included. A total of 150 patients of ARDS were selected. Data was collected as per the pre designed proforma and it included patients’ age, gender, clinical disorders precipitating ARDS, prescribing pattern of drugs and outcome. The data of the subjects was collected till discharge from hospital or death. Results: Infection was the cause of ARDS in 81.3% (n=122) of subjects. Antibiotics were prescribed in all the subjects and beta-lactams were prescribed in 97.3% (n=146). 41.3% (n=62) were prescribed corticosteroids, 39.3% (n=59) diuretics and 89.3% (n=134) intravenous fluids. Conclusion: The outcome of patients on different pharmacological treatment did not show any statistically significant difference. PMID:25859465

Respiratory cooling and thermoregulatory coupling in reptiles.

PubMed

Tattersall, Glenn J; Cadena, Viviana; Skinner, Matthew C

2006-11-01

Comparative physiological research on reptiles has focused primarily on the understanding of mechanisms of the control of breathing as they relate to respiratory gases or temperature itself. Comparatively less research has been done on the possible link between breathing and thermoregulation. Reptiles possess remarkable thermoregulatory capabilities, making use of behavioural and physiological mechanisms to regulate body temperature. The presence of thermal panting and gaping in numerous reptiles, coupled with the existence of head-body temperature differences, suggests that head temperature may be the primary regulated variable rather than body temperature. This review examines the preponderance of head and body temperature differences in reptiles, the occurrence of breathing patterns that possess putative thermoregulatory roles, and the propensity for head and brain temperature to be controlled by reptiles, particularly at higher temperatures. The available evidence suggests that these thermoregulatory breathing patterns are indeed present, though primarily in arid-dwelling reptiles. More importantly, however, it appears that the respiratory mechanisms that have the capacity to cool evolved initially in reptiles, perhaps as regulatory mechanisms for preventing overheating of the brain. Examining the control of these breathing patterns and their efficacy at regulating head or brain temperature may shed light on the evolution of thermoregulatory mechanisms in other vertebrates, namely the endothermic mammals and birds.

Management of the infant with respiratory syncytial virus.

PubMed

Corey, M A; Clore, E R

1991-04-01

This article examines updated clinical information concerning respiratory syncytial virus (RSV) infection including epidemiology, pathology, clinical manifestations, diagnosis, treatment, nosocomial infection, and prognosis. Also presented is current information on ribavirin therapy, its side effects, and precautions. Research related to the most effective isolation methodology is discussed, as well as nursing diagnoses based on Gordon's Functional Health Patterns and interventions for the infant hospitalized with RSV bronchiolitis and/or pneumonia.

On the respiratory flow in the cuttlefish sepia officinalis.

PubMed

Bone, Q; Brown, E; Travers, G

1994-09-01

The respiratory flow of water over the gills of the cuttlefish Sepia officinalis at rest is produced by the alternate activity of the radial muscles of the mantle and the musculature of the collar flaps; mantle circular muscle fibres are not involved. Inspiration takes place as the radial fibres contract, thinning the mantle and expanding the mantle cavity. The rise in mantle cavity pressure (up to 0.15 kPa), expelling water via the siphon during expiration, is brought about by inward movement of the collar flaps and (probably) mainly by elastic recoil of the mantle connective tissue network 'wound up' by radial fibre contraction during inspiration. Sepia also shows a second respiratory pattern, in which mantle cavity pressures during expiration are greater (up to 0.25 kPa). Here, the mantle circular fibres are involved, as they are during the large pressure transients (up to 10 kPa) seen during escape jetting. Active contraction of the muscles of the collar flaps is seen in all three patterns of expulsion of water from the mantle cavity, electrical activity increasing with increasing mantle cavity pressures. Respiratory expiration in the resting squid Loligo vulgaris is probably driven as in Sepia, whereas in the resting octopus Eledone cirrhosa, the mantle circular musculature is active during expiration. The significance of these observations is discussed.

Challenges of Developing Communicative Interaction in Individuals with Congenital Profound Intellectual and Multiple Disabilities

ERIC Educational Resources Information Center

Blain-Moraes, Stefanie; Chau, Tom

2012-01-01

Background: Physiological responses have been used in individuals with acquired disability to enable communicative interaction without motor movement. This study explored four autonomic nervous system (ANS) signals--electrodermal activity, skin temperature, cardiac patterns and respiratory patterns--to enable interaction with individuals born with…

Epidemiological Features and Antibiotic Resistance Patterns of Haemophilus influenzae Originating from Respiratory Tract and Vaginal Specimens in Pediatric Patients.

PubMed

Li, Jian-Ping; Hua, Chun-Zhen; Sun, Li-Ying; Wang, Hong-Jiao; Chen, Zhi-Min; Shang, Shi-Qiang

2017-12-01

Haemophilus influenzae (H. influenzae) is a common pathogen of respiratory tract infections in children, however, as a possible cause of vulvovaginitis in prepubertal girls, its epidemiological features, antibiotic-resistance patterns, and treatment are seldom noted. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Specimens obtained from patients were inoculated on Haemophilus selective medium; and drug-sensitivities tests were determined using the disk diffusion method. A cefinase disk was used to detect β-lactamase. A total of 610 H. influenzae strains, 81.6% (498/610) from the respiratory tract and 18.0% (110/610) from the vagina, were identified in the Children's Hospital in 2015. The age of the children with respiratory tract strains were significantly younger than those with vaginal strains (P < .001). The H. influenzae isolation rate in May was the highest. The β-lactamase positive rate was 51.5% (314/610), and 52.5% (320/610) were resistant to ampicillin. The susceptibilities rates to cefuroxime, ampicillin/sulbactam, cefotaxime, clarithromycin, and sulfamethoxazole-trimethoprim were 72.1% (440/610), 95.9%, 96.4% (588/610), 81.8% (499/610), and 36.4% (222/610), respectively. Higher resistance to ampicillin, cefuroxime, clarithromycin, and sulfamethoxazole-trimethoprim were found in respiratory tract strains, compared with vaginal strains (P < .05). All of the patients with H. influenzae in the respiratory tract were cured with oral or intravenous β-lactam antibiotics. Of all patients with vaginal strains, 50% (55/110) were cured with topical ofloxacin gel, and 44.5% (49/110) were cured with oral β-lactam antibiotics. The drug-resistance rates of H. influenzae isolated from vagina were lower than those from the respiratory tract. Topical ofloxacin gel or oral β-lactam antibiotics are effective treatments to eliminate the H. influenza causing infection in the vagina. Copyright © 2017 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Novel insights in cough and breathing patterns of patients with idiopathic pulmonary fibrosis performing repeated 24-hour-respiratory polygraphies.

PubMed

Schertel, Anke; Funke-Chambour, Manuela; Geiser, Thomas; Brill, Anne-Kathrin

2017-11-13

The main symptoms of patients with idiopathic pulmonary fibrosis (IPF) are cough and dyspnea. IPF leads to a restrictive lung disorder impacting daytime and nocturnal breathing patterns. In this pilot study we assessed the course of day- and nighttime respiration, oxygenation, and cough over a period of 8 months as well as differences between wakefulness and sleep in IPF patients. Repetitive 24-h respiratory polygraphies (RP) and pulmonary function tests were performed at baseline and after 3, 4, 7 and 8 months. Cough-index, oxygenation parameters (SpO2, time with SpO2 < 90%, desaturation index), respiratory rate and heart rate were assessed for differences between wakefulness and sleep. The first and the last RP were compared to identify changes of these parameters over time. Statistical analyses were performed with Wilcoxon signed rank tests. Nine IPF patients (8 male, median age 67 years (IQR 60, 77) with 37 valid 24-h RPs were included. Eight patients (88.9%) received antifibrotic treatment. Cough was more prevalent during wakefulness with a median cough-index of 14.8/h (IQR 10.9, 16.8) and 1.6/h (IQR 1.3-2.8) during sleep, p = 0.0039. Oxygenation parameters showed no difference, while respiratory- and heart rate were significantly higher during wakefulness. Despite stable pulmonary function tests over 8 months, the initially elevated respiratory rate increased further during wakefulness (baseline RR median 25.7/min (IQR 19.8, 26.6) vs. RR median 32.2/min (IQR 26.5, 40.9) at follow-up, p = 0.0273). The other respiratory parameters remained stable over time. Cough in IPF patients is more prevalent during wakefulness than during sleep. Further studies with a larger sample size and longer a follow-up period are needed to evaluate the role of the respiratory rate during wakefulness as a potential clinical follow up parameter in IPF.

Rib Cage Deformities Alter Respiratory Muscle Action and Chest Wall Function in Patients with Severe Osteogenesis Imperfecta

PubMed Central

LoMauro, Antonella; Pochintesta, Simona; Romei, Marianna; D'Angelo, Maria Grazia; Pedotti, Antonio; Turconi, Anna Carla; Aliverti, Andrea

2012-01-01

Background Osteogenesis imperfecta (OI) is an inherited connective tissue disorder characterized by bone fragility, multiple fractures and significant chest wall deformities. Cardiopulmonary insufficiency is the leading cause of death in these patients. Methods Seven patients with severe OI type III, 15 with moderate OI type IV and 26 healthy subjects were studied. In addition to standard spirometry, rib cage geometry, breathing pattern and regional chest wall volume changes at rest in seated and supine position were assessed by opto-electronic plethysmography to investigate if structural modifications of the rib cage in OI have consequences on ventilatory pattern. One-way or two-way analysis of variance was performed to compare the results between the three groups and the two postures. Results Both OI type III and IV patients showed reduced FVC and FEV1 compared to predicted values, on condition that updated reference equations are considered. In both positions, ventilation was lower in OI patients than control because of lower tidal volume (p<0.01). In contrast to OI type IV patients, whose chest wall geometry and function was normal, OI type III patients were characterized by reduced (p<0.01) angle at the sternum (pectus carinatum), paradoxical inspiratory inward motion of the pulmonary rib cage, significant thoraco-abdominal asynchronies and rib cage distortions in supine position (p<0.001). Conclusions In conclusion, the restrictive respiratory pattern of Osteogenesis Imperfecta is closely related to the severity of the disease and to the sternal deformities. Pectus carinatum characterizes OI type III patients and alters respiratory muscles coordination, leading to chest wall and rib cage distortions and an inefficient ventilator pattern. OI type IV is characterized by lower alterations in the respiratory function. These findings suggest that functional assessment and treatment of OI should be differentiated in these two forms of the disease. PMID:22558284

Internal respiratory surrogate in multislice 4D CT using a combination of Fourier transform and anatomical features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hui, Cheukkai; Suh, Yelin; Robertson, Daniel

Purpose: The purpose of this study was to develop a novel algorithm to create a robust internal respiratory signal (IRS) for retrospective sorting of four-dimensional (4D) computed tomography (CT) images. Methods: The proposed algorithm combines information from the Fourier transform of the CT images and from internal anatomical features to form the IRS. The algorithm first extracts potential respiratory signals from low-frequency components in the Fourier space and selected anatomical features in the image space. A clustering algorithm then constructs groups of potential respiratory signals with similar temporal oscillation patterns. The clustered group with the largest number of similar signalsmore » is chosen to form the final IRS. To evaluate the performance of the proposed algorithm, the IRS was computed and compared with the external respiratory signal from the real-time position management (RPM) system on 80 patients. Results: In 72 (90%) of the 4D CT data sets tested, the IRS computed by the authors’ proposed algorithm matched with the RPM signal based on their normalized cross correlation. For these data sets with matching respiratory signals, the average difference between the end inspiration times (Δt{sub ins}) in the IRS and RPM signal was 0.11 s, and only 2.1% of Δt{sub ins} were more than 0.5 s apart. In the eight (10%) 4D CT data sets in which the IRS and the RPM signal did not match, the average Δt{sub ins} was 0.73 s in the nonmatching couch positions, and 35.4% of them had a Δt{sub ins} greater than 0.5 s. At couch positions in which IRS did not match the RPM signal, a correlation-based metric indicated poorer matching of neighboring couch positions in the RPM-sorted images. This implied that, when IRS did not match the RPM signal, the images sorted using the IRS showed fewer artifacts than the clinical images sorted using the RPM signal. Conclusions: The authors’ proposed algorithm can generate robust IRSs that can be used for retrospective sorting of 4D CT data. The algorithm is completely automatic and requires very little processing time. The algorithm is cost efficient and can be easily adopted for everyday clinical use.« less

Infection prevention and control measures for acute respiratory infections in healthcare settings: an update.

PubMed

Seto, W H; Conly, J M; Pessoa-Silva, C L; Malik, M; Eremin, S

2013-01-01

Viruses account for the majority of the acute respiratory tract infections (ARIs) globally with a mortality exceeding 4 million deaths per year. The most commonly encountered viruses, in order of frequency, include influenza, respiratory syncytial virus, parainfluenza and adenovirus. Current evidence suggests that the major mode of transmission of ARls is through large droplets, but transmission through contact (including hand contamination with subsequent self-inoculation) and infectious respiratory aerosols of various sizes and at short range (coined as "opportunistic" airborne transmission) may also occur for some pathogens. Opportunistic airborne transmission may occur when conducting highrisk aerosol generating procedures and airborne precautions will be required in this setting. General infection control measures effective for all respiratory viral infections are reviewed and followed by discussion on some of the common viruses, including severe acute respiratory syndrome (SARS) coronavirus and the recently discovered novel coronavirus.

Healthcare-seeking behaviors for acute respiratory illness in two communities of Java, Indonesia: a cross-sectional survey

PubMed Central

Praptiningsih, Catharina Y.; Lafond, Kathryn E.; Wahyuningrum, Yunita; Storms, Aaron D.; Mangiri, Amalya; Iuliano, Angela D.; Samaan, Gina; Titaley, Christiana R.; Yelda, Fitra; Kreslake, Jennifer; Storey, Douglas; Uyeki, Timothy M.

2017-01-01

Understanding healthcare-seeking patterns for respiratory illness can help improve estimations of disease burden and inform public health interventions to control acute respiratory disease in Indonesia. The objectives of this study were to describe healthcare-seeking behaviors for respiratory illnesses in one rural and one urban community in Western Java, and to explore the factors that affect care seeking. From February 8, 2012 to March 1, 2012, a survey was conducted in 2520 households in the East Jakarta and Bogor districts to identify reported recent respiratory illnesses, as well as all hospitalizations from the previous 12-month period. We found that 4% (10% of those less than 5 years) of people had respiratory disease resulting in a visit to a healthcare provider in the past 2 weeks; these episodes were most commonly treated at government (33%) or private (44%) clinics. Forty-five people (0.4% of those surveyed) had respiratory hospitalizations in the past year, and just over half of these (24/45, 53%) occurred at a public hospital. Public health programs targeting respiratory disease in this region should account for care at private hospitals and clinics, as well as illnesses that are treated at home, in order to capture the true burden of illness in these communities. PMID:26930154

Healthcare-seeking behaviors for acute respiratory illness in two communities of Java, Indonesia: a cross-sectional survey.

PubMed

Praptiningsih, Catharina Y; Lafond, Kathryn E; Wahyuningrum, Yunita; Storms, Aaron D; Mangiri, Amalya; Iuliano, Angela D; Samaan, Gina; Titaley, Christiana R; Yelda, Fitra; Kreslake, Jennifer; Storey, Douglas; Uyeki, Timothy M

2016-06-01

Understanding healthcare-seeking patterns for respiratory illness can help improve estimations of disease burden and inform public health interventions to control acute respiratory disease in Indonesia. The objectives of this study were to describe healthcare-seeking behaviors for respiratory illnesses in one rural and one urban community in Western Java, and to explore the factors that affect care seeking. From February 8, 2012 to March 1, 2012, a survey was conducted in 2520 households in the East Jakarta and Bogor districts to identify reported recent respiratory illnesses, as well as all hospitalizations from the previous 12-month period. We found that 4% (10% of those less than 5years) of people had respiratory disease resulting in a visit to a healthcare provider in the past 2weeks; these episodes were most commonly treated at government (33%) or private (44%) clinics. Forty-five people (0.4% of those surveyed) had respiratory hospitalizations in the past year, and just over half of these (24/45, 53%) occurred at a public hospital. Public health programs targeting respiratory disease in this region should account for care at private hospitals and clinics, as well as illnesses that are treated at home, in order to capture the true burden of illness in these communities. Published by Elsevier Ltd.

Interactions between behaviorally relevant rhythms and synaptic plasticity alter coding in the piriform cortex

PubMed Central

Urban, Nathaniel N.

2012-01-01

Understanding how neural and behavioral timescales interact to influence cortical activity and stimulus coding is an important issue in sensory neuroscience. In air-breathing animals, voluntary changes in respiratory frequency alter the temporal patterning olfactory input. In the olfactory bulb, these behavioral timescales are reflected in the temporal properties of mitral/tufted (M/T) cell spike trains. As the odor information contained in these spike trains is relayed from the bulb to the cortex, interactions between presynaptic spike timing and short-term synaptic plasticity dictate how stimulus features are represented in cortical spike trains. Here we demonstrate how the timescales associated with respiratory frequency, spike timing and short-term synaptic plasticity interact to shape cortical responses. Specifically, we quantified the timescales of short-term synaptic facilitation and depression at excitatory synapses between bulbar M/T cells and cortical neurons in slices of mouse olfactory cortex. We then used these results to generate simulated M/T population synaptic currents that were injected into real cortical neurons. M/T population inputs were modulated at frequencies consistent with passive respiration or active sniffing. We show how the differential recruitment of short-term plasticity at breathing versus sniffing frequencies alters cortical spike responses. For inputs at sniffing frequencies, cortical neurons linearly encoded increases in presynaptic firing rates with increased phase locked, firing rates. In contrast, at passive breathing frequencies, cortical responses saturated with changes in presynaptic rate. Our results suggest that changes in respiratory behavior can gate the transfer of stimulus information between the olfactory bulb and cortex. PMID:22553016

Regulation of Breathing and Autonomic Outflows by Chemoreceptors

PubMed Central

Guyenet, Patrice G.

2016-01-01

Lung ventilation fluctuates widely with behavior but arterial PCO2 remains stable. Under normal conditions, the chemoreflexes contribute to PaCO2 stability by producing small corrective cardiorespiratory adjustments mediated by lower brainstem circuits. Carotid body (CB) information reaches the respiratory pattern generator (RPG) via nucleus solitarius (NTS) glutamatergic neurons which also target rostral ventrolateral medulla (RVLM) presympathetic neurons thereby raising sympathetic nerve activity (SNA). Chemoreceptors also regulate presympathetic neurons and cardiovagal preganglionic neurons indirectly via inputs from the RPG. Secondary effects of chemoreceptors on the autonomic outflows result from changes in lung stretch afferent and baroreceptor activity. Central respiratory chemosensitivity is caused by direct effects of acid on neurons and indirect effects of CO2 via astrocytes. Central respiratory chemoreceptors are not definitively identified but the retrotrapezoid nucleus (RTN) is a particularly strong candidate. The absence of RTN likely causes severe central apneas in congenital central hypoventilation syndrome. Like other stressors, intense chemosensory stimuli produce arousal and activate circuits that are wake- or attention-promoting. Such pathways (e.g., locus coeruleus, raphe, and orexin system) modulate the chemoreflexes in a state-dependent manner and their activation by strong chemosensory stimuli intensifies these reflexes. In essential hypertension, obstructive sleep apnea and congestive heart failure, chronically elevated CB afferent activity contributes to raising SNA but breathing is unchanged or becomes periodic (severe CHF). Extreme CNS hypoxia produces a stereotyped cardiorespiratory response (gasping, increased SNA). The effects of these various pathologies on brainstem cardiorespiratory networks are discussed, special consideration being given to the interactions between central and peripheral chemoreflexes. PMID:25428853

Hypoxic ventilatory response in Tac1-/- neonatal mice following exposure to opioids.

PubMed

Berner, J; Shvarev, Y; Zimmer, A; Wickstrom, R

2012-12-01

Morphine is the dominating analgetic drug used in neonates, but opioid-induced respiratory depression limits its therapeutic use. In this study, we examined acute morphine effects on respiration during intermittent hypoxia in newborn Tac1 gene knockout mice (Tac1-/-) lacking substance P and neurokinin A. In vivo, plethysmography revealed a blunted hypoxic ventilatory response (HVR) in Tac1-/- mice. Morphine (10 mg/kg) depressed the HVR in wild-type animals through an effect on respiratory frequency, whereas it increased tidal volumes in Tac1-/- during hypoxia, resulting in increased minute ventilation. Apneas were reduced during the first hypoxic episode in both morphine-exposed groups, but were restored subsequently in Tac1-/- mice. Morphine did not affect ventilation or apnea prevalence during baseline conditions. In vitro, morphine (50 nM) had no impact on anoxic response of brain stem preparations of either strain. In contrast, it suppressed the inspiratory rhythm during normoxia and potentiated development of posthypoxic neuronal arrest, especially in Tac1-/-. Thus this phenotype has a higher sensitivity to the depressive effects of morphine on inspiratory rhythm generation, but morphine does not modify the reactivity to oxygen deprivation. In conclusion, although Tac1-/- mice are similar to wild-type animals during normoxia, they differed by displaying a reversed pattern with an improved HVR during intermittent hypoxia both in vivo and in vitro. These data suggest that opioids and the substance P-ergic system interact in the HVR, and that reducing the activity in the tachykinin system may alter the respiratory effects of opioid treatment in newborns.

New clinical and histological patterns of acute disseminated histoplasmosis in human immunodeficiency virus-positive patients with acquired immunodeficiency syndrome.

PubMed

Ollague Sierra, Jose E; Ollague Torres, Jose M

2013-04-01

Histoplasmosis has attained increasing relevance in the past 3 decades because of the appearance of the human immunodeficiency virus (HIV). In most immunocompetent persons, the infection is asymptomatic or can produce a respiratory condition with symptoms and radiological images similar to those observed in pulmonary tuberculosis; in non-HIV+ immunocompromised patients, it can cause respiratory symptoms or evolve into a disseminated infection. The same can occur in acquired immunodeficiency syndrome (AIDS) patients. We have observed a series of HIV+ patients with AIDS who presented with cutaneous histoplasmosis and in whom the clinical and histopathological features were highly unusual, including variable mucocutaneous lesions that were difficult to diagnose clinically. These patients displayed unusual, previously undescribed, histological patterns, including lichenoid pattern, nodular pseudomyxoid pattern, pyogenic granuloma-like pattern, perifollicular pattern, and superficial (S), mid (M), and deep perivascular dermatitis; and more commonly encountered patterns, such as histiocytic lobular panniculitis and focal nodular dermatitis. The novel histopathological patterns of cutaneous involvement by histoplasmosis seen in these patients resembled other common inflammatory and infectious conditions and required a high level of suspicion and the application of special stains for organisms for confirmation. These new, clinical, and histological findings do not seem to be commonly encountered in HIV- patients infected with the fungus but seem to be displayed most prominently in HIV+ patients with AIDS.

Design of a new artificial breathing system for simulating the human respiratory activities.

PubMed

Essoukaki, Elmaati; Rattal, Mourad; Ben Taleb, Lhoucine; Harmouchi, Mohammed; Assir, Abdelhadi; Mouhsen, Azeddine; Lyazidi, Aissam

2018-01-01

The purpose of this work is the conception and implementation of an artificial active respiratory system that allows the simulation of human respiratory activities. The system consists of two modules, mechanical and electronical. The first one represents a cylindrical lung adjustable in resistance and compliance. This lung is located inside a transparent thoracic box, connected to a piston that generates variable respiratory efforts. The parameters of the system, which are pressure, flow and volume, are measured by the second module. A computer application was developed to control the whole system, and enables the display of the parameters. A series of tests were made to evaluate the respiratory efforts, resistances and compliances. The results were compared to the bibliographical studies, allowing the validation of the proposed system.

Morphology of the Oligoryzomys nigripes respiratory system.

PubMed

Mario, Lara Carolina; Borghesi, Jéssica; G Hayashi, Rafael; O Favaron, Phelipe; N Rodrigues, Marcio; C Carvalho, Rafael; Miglino, Maria A

2018-06-04

Rodents are important in the transmission of infectious diseases that affect the respiratory tract, including simple infections and those caused by specific pathogens. These animals are natural reservoirs of zoonoses that cause many public health diseases. Basic knowledge on the morphology of these animals is important as basic research is useful for applied studies, such as the development of clinical, therapeutic, surgical and clinical models. Morphological data of respiratory tract in Oligoryzomys nigripes are absent in the literature. Therefore, the aim of this study was to perform a morphological analysis of the respiratory tract of O. nigripes. Five adult females from the environmental reserve in São Joaquim da Barra, São Paulo were used, donated to the Museum of Veterinary Anatomy (FMVZ/USP). Several morphological features follow the same pattern seen in rodents; however, this species showed some differences such as the presence of three lobar bronchi, nonlobed left lung and the right lung constituted by two lobes. Respiratory epithelium lined the whole respiratory tract and was seen using scanning electron microscopy the oval shape of the parenchyma and alveoli. © 2018 Blackwell Verlag GmbH.

Ensemble framework based real-time respiratory motion prediction for adaptive radiotherapy applications.

PubMed

Tatinati, Sivanagaraja; Nazarpour, Kianoush; Tech Ang, Wei; Veluvolu, Kalyana C

2016-08-01

Successful treatment of tumors with motion-adaptive radiotherapy requires accurate prediction of respiratory motion, ideally with a prediction horizon larger than the latency in radiotherapy system. Accurate prediction of respiratory motion is however a non-trivial task due to the presence of irregularities and intra-trace variabilities, such as baseline drift and temporal changes in fundamental frequency pattern. In this paper, to enhance the accuracy of the respiratory motion prediction, we propose a stacked regression ensemble framework that integrates heterogeneous respiratory motion prediction algorithms. We further address two crucial issues for developing a successful ensemble framework: (1) selection of appropriate prediction methods to ensemble (level-0 methods) among the best existing prediction methods; and (2) finding a suitable generalization approach that can successfully exploit the relative advantages of the chosen level-0 methods. The efficacy of the developed ensemble framework is assessed with real respiratory motion traces acquired from 31 patients undergoing treatment. Results show that the developed ensemble framework improves the prediction performance significantly compared to the best existing methods. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Neural network for photoplethysmographic respiratory rate monitoring

NASA Astrophysics Data System (ADS)

Johansson, Anders

2001-10-01

The photoplethysmographic signal (PPG) includes respiratory components seen as frequency modulation of the heart rate (respiratory sinus arrhythmia, RSA), amplitude modulation of the cardiac pulse, and respiratory induced intensity variations (RIIV) in the PPG baseline. The aim of this study was to evaluate the accuracy of these components in determining respiratory rate, and to combine the components in a neural network for improved accuracy. The primary goal is to design a PPG ventilation monitoring system. PPG signals were recorded from 15 healthy subjects. From these signals, the systolic waveform, diastolic waveform, respiratory sinus arrhythmia, pulse amplitude and RIIV were extracted. By using simple algorithms, the rates of false positive and false negative detection of breaths were calculated for each of the five components in a separate analysis. Furthermore, a simple neural network (NN) was tried out in a combined pattern recognition approach. In the separate analysis, the error rates (sum of false positives and false negatives) ranged from 9.7% (pulse amplitude) to 14.5% (systolic waveform). The corresponding value of the NN analysis was 9.5-9.6%.

Exhaled Aerosol Pattern Discloses Lung Structural Abnormality: A Sensitivity Study Using Computational Modeling and Fractal Analysis

PubMed Central

Xi, Jinxiang; Si, Xiuhua A.; Kim, JongWon; Mckee, Edward; Lin, En-Bing

2014-01-01

Background Exhaled aerosol patterns, also called aerosol fingerprints, provide clues to the health of the lung and can be used to detect disease-modified airway structures. The key is how to decode the exhaled aerosol fingerprints and retrieve the lung structural information for a non-invasive identification of respiratory diseases. Objective and Methods In this study, a CFD-fractal analysis method was developed to quantify exhaled aerosol fingerprints and applied it to one benign and three malign conditions: a tracheal carina tumor, a bronchial tumor, and asthma. Respirations of tracer aerosols of 1 µm at a flow rate of 30 L/min were simulated, with exhaled distributions recorded at the mouth. Large eddy simulations and a Lagrangian tracking approach were used to simulate respiratory airflows and aerosol dynamics. Aerosol morphometric measures such as concentration disparity, spatial distributions, and fractal analysis were applied to distinguish various exhaled aerosol patterns. Findings Utilizing physiology-based modeling, we demonstrated substantial differences in exhaled aerosol distributions among normal and pathological airways, which were suggestive of the disease location and extent. With fractal analysis, we also demonstrated that exhaled aerosol patterns exhibited fractal behavior in both the entire image and selected regions of interest. Each exhaled aerosol fingerprint exhibited distinct pattern parameters such as spatial probability, fractal dimension, lacunarity, and multifractal spectrum. Furthermore, a correlation of the diseased location and exhaled aerosol spatial distribution was established for asthma. Conclusion Aerosol-fingerprint-based breath tests disclose clues about the site and severity of lung diseases and appear to be sensitive enough to be a practical tool for diagnosis and prognosis of respiratory diseases with structural abnormalities. PMID:25105680

Rényi entropy and Lempel-Ziv complexity of mechanomyographic recordings of diaphragm muscle as indexes of respiratory effort.

PubMed

Torres, Abel; Fiz, Jose A; Jane, Raimon; Laciar, Eric; Galdiz, Juan B; Gea, Joaquim; Morera, Josep

2008-01-01

The study of the mechanomyographic (MMG) signals of respiratory muscles is a promising technique in order to evaluate the respiratory muscles effort. A new approach for quantifying the relationship between respiratory MMG signals and respiratory effort is presented by analyzing the spatio-temporal patterns in the MMG signal using two non-linear methods: Rényi entropy and Lempel-Ziv (LZ) complexity analysis. Both methods are well suited to the analysis of non-stationary biomedical signals of short length. In this study, MMG signals of the diaphragm muscle acquired by means of a capacitive accelerometer applied on the costal wall were analyzed. The method was tested on an animal model (dogs), and the diaphragmatic MMG signal was recorded continuously while two non anesthetized mongrel dogs performed a spontaneous ventilation protocol with an incremental inspiratory load. The performance in discriminating high and low respiratory effort levels with these two methods was analyzed with the evaluation of the Pearson correlation coefficient between the MMG parameters and respiratory effort parameters extracted from the inspiratory pressure signal. The results obtained show an increase of the MMG signal Rényi entropy and LZ complexity values with the increase of the respiratory effort. Compared with other parameters analyzed in previous works, both Rényi entropy and LZ complexity indexes demonstrates better performance in all the signals analyzed. Our results suggest that these non-linear techniques are useful to detect and quantify changes in the respiratory effort by analyzing MMG respiratory signals.

Critically Ill Patients With the Middle East Respiratory Syndrome: A Multicenter Retrospective Cohort Study.

PubMed

Arabi, Yaseen M; Al-Omari, Awad; Mandourah, Yasser; Al-Hameed, Fahad; Sindi, Anees A; Alraddadi, Basem; Shalhoub, Sarah; Almotairi, Abdullah; Al Khatib, Kasim; Abdulmomen, Ahmed; Qushmaq, Ismael; Mady, Ahmed; Solaiman, Othman; Al-Aithan, Abdulsalam M; Al-Raddadi, Rajaa; Ragab, Ahmed; Al Mekhlafi, Ghaleb A; Al Harthy, Abdulrahman; Kharaba, Ayman; Ahmadi, Mashael Al; Sadat, Musharaf; Mutairi, Hanan Al; Qasim, Eman Al; Jose, Jesna; Nasim, Maliha; Al-Dawood, Abdulaziz; Merson, Laura; Fowler, Robert; Hayden, Frederick G; Balkhy, Hanan H

2017-10-01

To describe patient characteristics, clinical manifestations, disease course including viral replication patterns, and outcomes of critically ill patients with severe acute respiratory infection from the Middle East respiratory syndrome and to compare these features with patients with severe acute respiratory infection due to other etiologies. Retrospective cohort study. Patients admitted to ICUs in 14 Saudi Arabian hospitals. Critically ill patients with laboratory-confirmed Middle East respiratory syndrome severe acute respiratory infection (n = 330) admitted between September 2012 and October 2015 were compared to consecutive critically ill patients with community-acquired severe acute respiratory infection of non-Middle East respiratory syndrome etiology (non-Middle East respiratory syndrome severe acute respiratory infection) (n = 222). None. Although Middle East respiratory syndrome severe acute respiratory infection patients were younger than those with non-Middle East respiratory syndrome severe acute respiratory infection (median [quartile 1, quartile 3] 58 yr [44, 69] vs 70 [52, 78]; p < 0.001), clinical presentations and comorbidities overlapped substantially. Patients with Middle East respiratory syndrome severe acute respiratory infection had more severe hypoxemic respiratory failure (PaO2/FIO2: 106 [66, 160] vs 176 [104, 252]; p < 0.001) and more frequent nonrespiratory organ failure (nonrespiratory Sequential Organ Failure Assessment score: 6 [4, 9] vs 5 [3, 7]; p = 0.002), thus required more frequently invasive mechanical ventilation (85.2% vs 73.0%; p < 0.001), oxygen rescue therapies (extracorporeal membrane oxygenation 5.8% vs 0.9%; p = 0.003), vasopressor support (79.4% vs 55.0%; p < 0.001), and renal replacement therapy (48.8% vs 22.1%; p < 0.001). After adjustment for potential confounding factors, Middle East respiratory syndrome was independently associated with death compared to non-Middle East respiratory syndrome severe acute respiratory infection (adjusted odds ratio, 5.87; 95% CI, 4.02-8.56; p < 0.001). Substantial overlap exists in the clinical presentation and comorbidities among patients with Middle East respiratory syndrome severe acute respiratory infection from other etiologies; therefore, a high index of suspicion combined with diagnostic testing is essential component of severe acute respiratory infection investigation for at-risk patients. The lack of distinguishing clinical features, the need to rely on real-time reverse transcription polymerase chain reaction from respiratory samples, variability in viral shedding duration, lack of effective therapy, and high mortality represent substantial clinical challenges and help guide ongoing clinical research efforts.

The adenoid as a key factor in upper airway infections.

PubMed

van Cauwenberge, P B; Bellussi, L; Maw, A R; Paradise, J L; Solow, B

1995-06-01

The adenoids (and the nasopharynx) play a key role in the normal functioning and in various pathologies of the upper respiratory tract. In this paper the role of adenoidal pathology and the beneficial effect of adenoidectomy in some upper respiratory tract and facial anomalies and diseases are discussed; otitis media with effusion, recurrent acute otitis media, sinusitis, snoring and sleep apnea and abnormal patterns in the midface growth and development.

CAP, epilepsy and motor events during sleep: the unifying role of arousal.

PubMed

Parrino, Liborio; Halasz, Peter; Tassinari, Carlo Alberto; Terzano, Mario Giovanni

2006-08-01

Arousal systems play a topical neurophysiologic role in protecting and tailoring sleep duration and depth. When they appear in NREM sleep, arousal responses are not limited to a single EEG pattern but are part of a continuous spectrum of EEG modifications ranging from high-voltage slow rhythms to low amplitude fast activities. The hierarchic features of arousal responses are reflected in the phase A subtypes of CAP (cyclic alternating pattern) including both slow arousals (dominated by the <1Hz oscillation) and fast arousals (ASDA arousals). CAP is an infraslow oscillation with a periodicity of 20-40s that participates in the dynamic organization of sleep and in the activation of motor events. Physiologic, paraphysiologic and pathologic motor activities during NREM sleep are always associated with a stereotyped arousal pattern characterized by an initial increase in EEG delta power and heart rate, followed by a progressive activation of faster EEG frequencies. These findings suggest that motor patterns are already written in the brain codes (central pattern generators) embraced with an automatic sequence of EEG-vegetative events, but require a certain degree of activation (arousal) to become visibly apparent. Arousal can appear either spontaneously or be elicited by internal (epileptic burst) or external (noise, respiratory disturbance) stimuli. Whether the outcome is a physiologic movement, a muscle jerk or a major epileptic attack will depend on a number of ongoing factors (sleep stage, delta power, neuro-motor network) but all events share the common trait of arousal-activated phenomena.

The respiratory-vocal system of songbirds: anatomy, physiology, and neural control.

PubMed

Schmidt, Marc F; Martin Wild, J

2014-01-01

This wide-ranging review presents an overview of the respiratory-vocal system in songbirds, which are the only other vertebrate group known to display a degree of respiratory control during song rivalling that of humans during speech; this despite the fact that the peripheral components of both the respiratory and vocal systems differ substantially in the two groups. We first provide a brief description of these peripheral components in songbirds (lungs, air sacs and respiratory muscles, vocal organ (syrinx), upper vocal tract) and then proceed to a review of the organization of central respiratory-related neurons in the spinal cord and brainstem, the latter having an organization fundamentally similar to that of the ventral respiratory group of mammals. The second half of the review describes the nature of the motor commands generated in a specialized "cortical" song control circuit and how these might engage brainstem respiratory networks to shape the temporal structure of song. We also discuss a bilaterally projecting "respiratory-thalamic" pathway that links the respiratory system to "cortical" song control nuclei. This necessary pathway for song originates in the brainstem's primary inspiratory center and is hypothesized to play a vital role in synchronizing song motor commands both within and across hemispheres. © 2014 Elsevier B.V. All rights reserved.

The respiratory-vocal system of songbirds: Anatomy, physiology, and neural control

PubMed Central

Schmidt, Marc F.; Wild, J. Martin

2015-01-01

This wide-ranging review presents an overview of the respiratory-vocal system in songbirds, which are the only other vertebrate group known to display a degree of respiratory control during song rivalling that of humans during speech; this despite the fact that the peripheral components of both the respiratory and vocal systems differ substantially in the two groups. We first provide a brief description of these peripheral components in songbirds (lungs, air sacs and respiratory muscles, vocal organ (syrinx), upper vocal tract) and then proceed to a review of the organization of central respiratory-related neurons in the spinal cord and brainstem, the latter having an organization fundamentally similar to that of the ventral respiratory group of mammals. The second half of the review describes the nature of the motor commands generated in a specialized “cortical” song control circuit and how these might engage brainstem respiratory networks to shape the temporal structure of song. We also discuss a bilaterally projecting “respiratory-thalamic” pathway that links the respiratory system to “cortical” song control nuclei. This necessary pathway for song originates in the brainstem’s primary inspiratory center and is hypothesized to play a vital role in synchronizing song motor commands both within and across hemispheres. PMID:25194204

Modeling respiratory mechanics in the MCAT and spline-based MCAT phantoms

NASA Astrophysics Data System (ADS)

Segars, W. P.; Lalush, D. S.; Tsui, B. M. W.

2001-02-01

Respiratory motion can cause artifacts in myocardial SPECT and computed tomography (CT). The authors incorporate models of respiratory mechanics into the current 4D MCAT and into the next generation spline-based MCAT phantoms. In order to simulate respiratory motion in the current MCAT phantom, the geometric solids for the diaphragm, heart, ribs, and lungs were altered through manipulation of parameters defining them. Affine transformations were applied to the control points defining the same respiratory structures in the spline-based MCAT phantom to simulate respiratory motion. The Non-Uniform Rational B-Spline (NURBS) surfaces for the lungs and body outline were constructed in such a way as to be linked to the surrounding ribs. Expansion and contraction of the thoracic cage then coincided with expansion and contraction of the lungs and body. The changes both phantoms underwent were spline-interpolated over time to create time continuous 4D respiratory models. The authors then used the geometry-based and spline-based MCAT phantoms in an initial simulation study of the effects of respiratory motion on myocardial SPECT. The simulated reconstructed images demonstrated distinct artifacts in the inferior region of the myocardium. It is concluded that both respiratory models can be effective tools for researching effects of respiratory motion.

Diaphragmatic fatigue in man.

PubMed

Roussos, C S; Macklem, P T

1977-08-01

The time required (tlim) to produce fatigue of the diaphragm was determined in three normal seated subjects, breathing through a variety of high alinear, inspiratory resistances. During each breath in all experimental runs the subject generated a transdiaphragmatic pressure (Pdi) which was a predetermined fraction of his maximum inspiratory Pdi (Pdimax) at functional residual capacity. The breathing test was performed until the subject was unable to generate this Pdi. The relationship between Pdi/Pdimax and tlim was curvilinear so that when Pdi/Pdimax was small tlim increased markedly for little changes in Pdi/Pdimax. The value of Pdi/Pdimax that could be generated indefinitely (Pdicrit) was around 0.4. Hypoxia appeared to have no influence on Pdicrit, but probably led to a reduction in tlim at Pdi greater than Pdicrit for equal rates of energy consumption. Insofar as the behavior of the diaphragm reflects that of other respiratory muscles it appears that quite high inspiratory loads can be tolerated indefinitely. However, when the energy consumption of the respiratory muscles exceeds a critical level, fatigue should develop. This may be a mechanism of respiratory failure in a variety in a variety of lung diseases.

Air Pressure Responses to Sudden Vocal Tract Pressure Bleeds During Production of Stop Consonants: New Evidence of Aeromechanical Regulation

PubMed Central

Zajac, David J.; Weissler, Mark C.

2011-01-01

Two studies were conducted to evaluate short-latency vocal tract air pressure responses to sudden pressure bleeds during production of voiceless bilabial stop consonants. It was hypothesized that the occurrence of respiratory reflexes would be indicated by distinct patterns of responses as a function of bleed magnitude. In Study 1, 19 adults produced syllable trains of /pΛ/ using a mouthpiece coupled to a computer-controlled perturbator. The device randomly created bleed apertures that ranged from 0 to 40 mm2 during production of the 2nd or 4th syllable of an utterance. Although peak oral air pressure dropped in a linear manner across bleed apertures, it averaged 2 to 3 cm H2O at the largest bleed. While slope of oral pressure also decreased in a linear trend, duration of the oral pressure pulse remained relatively constant. The patterns suggest that respiratory reflexes, if present, have little effect on oral air pressure levels. In Study 2, both oral and subglottal air pressure responses were monitored in 2 adults while bleed apertures of 20 and 40 mm2 were randomly created. For 1 participant, peak oral air pressure dropped across bleed apertures, as in Study 1. Subglottal air pressure and slope, however, remained relatively stable. These patterns provide some support for the occurrence of respiratory reflexes to regulate subglottal air pressure. Overall, the studies indicate that the inherent physiologic processes of the respiratory system, which may involve reflexes, and passive aeromechanical resistance of the upper airway are capable of developing oral air pressure in the face of substantial pressure bleeds. Implications for understanding speech production and the characteristics of individuals with velopharyngeal dysfunction are discussed. PMID:15324286

CLINICAL APPLICATION OF THE RIGHT SIDELYING RESPIRATORY LEFT ADDUCTOR PULL BACK EXERCISE

PubMed Central

2013-01-01

Problem: Lumbopelvic‐femoral conditions are common and may be associated with asymmetrical musculoskeletal and respiratory impairments and postural mal‐alignment called a Left Anterior Interior Chain (AIC) pattern. An inherent pattern of asymmetry involves the trunk/ribs/spine/pelvis/hip joints and includes the tendency to stand on the right leg and shift the center of gravity to the right which may result for example, in a tight left posterior hip capsule, poorly approximated left hip, long/weak left adductors, internal obliques (IO) and transverse abdominus (TA), short/strong/over active paraspinals and muscles on the right anterior outlet (adductors, levator ani and obturator internus), a left rib flare and a decreased respiratory diaphragm zone of apposition (ZOA). The Solution: A therapeutic exercise technique that can address impairments associated with postural asymmetry may be beneficial in improving function, reducing and/or eliminating pain causation, and improving breathing. The Right Sidelying Left Respiratory Adductor Pull Back is an exercise designed to affect alignment of the lumbopelvic‐femoral region by influencing the left posterior ischiofemoral ligament, ZOA and right anterior outlet and left anterior inlet (rectus femoris, sartorius), activating/shortening the left adductors, left IO/TA's and inhibiting/lengthening the paraspinals, bilaterally. Discussion: The exercise technique is often used by Physical Therapists, Physical Therapist assistants and Athletic Trainers as an initial exercise to positively affect position/alignment of the lumbopelvic‐femoral region, referred to as “repositioning,” by clinicians who use it. Four published case studies have used similar exercises to address the above impairments associated with a Left AIC pattern and in each 100% improvement in function and pain intensity was described. This particular exercise technique is relatively new and warrants future research. PMID:23772350

Inspiratory muscular weakness is most evident in chronic stroke survivors with lower walking speeds.

PubMed

Pinheiro, M B; Polese, J C; Faria, C D; Machado, G C; Parreira, V F; Britto, R R; Teixeira-Salmela, L F

2014-06-01

Respiratory muscular weakness and associated changes in thoracoabdominal motion have been poorly studied in stroke subjects, since the individuals' functional levels were not previously considered in the investigations. To investigate the breathing patterns, thoracoabdominal motion, and respiratory muscular strength in chronic stroke subjects, who were stratified into two groups, according to their walking speeds. Cross-sectional, observational study. University laboratory. Eighty-nine community-dwelling chronic stroke subjects The subjects, according to their gait speeds, were stratified into community (gait speed ≥0.8 m/s) and non-community ambulators (gait speed <0.8 m/s). Variables related to pulmonary function, breathing patterns, and thoracoabdominal motions were assessed. Measures of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were obtained and were compared with the reference values for the Brazilian population. The MIP and MEP values were expressed as percentages of the predicted values. Mann-Whitney-U or independent Student t-tests were employed to compare the differences between the two groups for the selected variables. No significant between-group differences were found for the variables related to the breathing patterns and thoracoabdominal motions (0.01 < z/t < 1.51; 0.14

Clinical application of the right sidelying respiratory left adductor pull back exercise.

PubMed

Boyle, Kyndall L

2013-06-01

Lumbopelvic-femoral conditions are common and may be associated with asymmetrical musculoskeletal and respiratory impairments and postural mal-alignment called a Left Anterior Interior Chain (AIC) pattern. An inherent pattern of asymmetry involves the trunk/ribs/spine/pelvis/hip joints and includes the tendency to stand on the right leg and shift the center of gravity to the right which may result for example, in a tight left posterior hip capsule, poorly approximated left hip, long/weak left adductors, internal obliques (IO) and transverse abdominus (TA), short/strong/over active paraspinals and muscles on the right anterior outlet (adductors, levator ani and obturator internus), a left rib flare and a decreased respiratory diaphragm zone of apposition (ZOA). A therapeutic exercise technique that can address impairments associated with postural asymmetry may be beneficial in improving function, reducing and/or eliminating pain causation, and improving breathing. The Right Sidelying Left Respiratory Adductor Pull Back is an exercise designed to affect alignment of the lumbopelvic-femoral region by influencing the left posterior ischiofemoral ligament, ZOA and right anterior outlet and left anterior inlet (rectus femoris, sartorius), activating/shortening the left adductors, left IO/TA's and inhibiting/lengthening the paraspinals, bilaterally. The exercise technique is often used by Physical Therapists, Physical Therapist assistants and Athletic Trainers as an initial exercise to positively affect position/alignment of the lumbopelvic-femoral region, referred to as "repositioning," by clinicians who use it. Four published case studies have used similar exercises to address the above impairments associated with a Left AIC pattern and in each 100% improvement in function and pain intensity was described. This particular exercise technique is relatively new and warrants future research.

Short-term sustained hypoxia induces changes in the coupling of sympathetic and respiratory activities in rats

PubMed Central

Moraes, Davi J A; Bonagamba, Leni G H; Costa, Kauê M; Costa-Silva, João H; Zoccal, Daniel B; Machado, Benedito H

2014-01-01

Individuals experiencing sustained hypoxia (SH) exhibit adjustments in the respiratory and autonomic functions by neural mechanisms not yet elucidated. In the present study we evaluated the central mechanisms underpinning the SH-induced changes in the respiratory pattern and their impact on the sympathetic outflow. Using a decerebrated arterially perfused in situ preparation, we verified that juvenile rats exposed to SH (10% O2) for 24 h presented an active expiratory pattern, with increased abdominal, hypoglossal and vagal activities during late-expiration (late-E). SH also enhanced the activity of augmenting-expiratory neurones and depressed the activity of post-inspiratory neurones of the Bötzinger complex (BötC) by mechanisms not related to changes in their intrinsic electrophysiological properties. SH rats exhibited high thoracic sympathetic activity and arterial pressure levels associated with an augmented firing frequency of pre-sympathetic neurones of the rostral ventrolateral medulla (RVLM) during the late-E phase. The antagonism of ionotropic glutamatergic receptors in the BötC/RVLM abolished the late-E bursts in expiratory and sympathetic outputs of SH rats, indicating that glutamatergic inputs to the BötC/RVLM are essential for the changes in the expiratory and sympathetic coupling observed in SH rats. We also observed that the usually silent late-E neurones of the retrotrapezoid nucleus/parafacial respiratory group became active in SH rats, suggesting that this neuronal population may provide the excitatory drive essential to the emergence of active expiration and sympathetic overactivity. We conclude that short-term SH induces the activation of medullary expiratory neurones, which affects the pattern of expiratory motor activity and its coupling with sympathetic activity. PMID:24614747

Sigh rate and respiratory variability during mental load and sustained attention.

PubMed

Vlemincx, Elke; Taelman, Joachim; De Peuter, Steven; Van Diest, Ilse; Van den Bergh, Omer

2011-01-01

Spontaneous breathing consists of substantial correlated variability: Parameters characterizing a breath are correlated with parameters characterizing previous and future breaths. On the basis of dynamic system theory, negative emotion states are predicted to reduce correlated variability whereas sustained attention is expected to reduce total respiratory variability. Both are predicted to evoke sighing. To test this, respiratory variability and sighing were assessed during a baseline, stressful mental arithmetic task, nonstressful sustained attention task, and recovery in between tasks. For respiration rate (excluding sighs), reduced total variability was found during the attention task, whereas correlated variation was reduced during mental load. Sigh rate increased during mental load and during recovery from the attention task. It is concluded that mental load and task-related attention show specific patterns in respiratory variability and sigh rate. Copyright © 2010 Society for Psychophysiological Research.

Respiratory Sinus Arrhythmia and Heart Period in Infancy as Correlates of Later Oppositional Defiant and Callous-Unemotional Behaviors

ERIC Educational Resources Information Center

Wagner, Nicholas; Mills-Koonce, Roger; Willoughby, Michael; Propper, Cathi; Rehder, Peter; Gueron-Sela, Noa

2017-01-01

Extant literature suggests that oppositional defiant disorder (ODD) and callous-unemotional (CU) behaviors in childhood and adolescence are associated with distinct patterns of psychophysiological functioning, and that individual differences in these patterns have implications for developmental pathways to disorder. Very little is known about the…

REGIONAL DEPOSITION DOSE OF INHALED NANO-SIZE PARTICLES IN HUMAN LUNGS DURING CONTROLLED NORMAL BREATHING

EPA Science Inventory

INTRODUCTION

One of the key factors for affecting respiratory

deposition of particles is the breathing pattern of

individual subjects. Although idealized breathing

patterns (square or sine wave form) are frequently used

for studying lung deposit...

29 CFR 801.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... stress analyzers, or psychological stress evaluators, include any systems that utilize voice stress..., respiratory, and electrodermal patterns as minimum instrumentation standards; and (2) Is used, or the results...

29 CFR 801.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... stress analyzers, or psychological stress evaluators, include any systems that utilize voice stress..., respiratory, and electrodermal patterns as minimum instrumentation standards; and (2) Is used, or the results...

29 CFR 801.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... stress analyzers, or psychological stress evaluators, include any systems that utilize voice stress..., respiratory, and electrodermal patterns as minimum instrumentation standards; and (2) Is used, or the results...

A computer-aided audit system for respiratory therapy consult evaluations: description of a method and early results.

PubMed

Kester, Lucy; Stoller, James K

2013-05-01

Use of respiratory therapist (RT)-guided protocols enhances allocation of respiratory care. In the context that optimal protocol use requires a system for auditing respiratory care plans to assure adherence to protocols and expertise of the RTs generating the care plan, a live audit system has been in longstanding use in our Respiratory Therapy Consult Service. Growth in the number of RT positions and the need to audit more frequently has prompted development of a new, computer-aided audit system. The number and results of audits using the old and new systems were compared (for the periods May 30, 2009 through May 30, 2011 and January 1, 2012 through May 30, 2012, respectively). In contrast to the original, live system requiring a patient visit by the auditor, the new system involves completion of a respiratory therapy care plan using patient information in the electronic medical record, both by the RT generating the care plan and the auditor. Completing audits in the new system also uses an electronic respiratory therapy management system. The degrees of concordance between the audited RT's care plans and the "gold standard" care plans using the old and new audit systems were similar. Use of the new system was associated with an almost doubling of the rate of audits (ie, 11 per month vs 6.1 per month). The new, computer-aided audit system increased capacity to audit more RTs performing RT-guided consults while preserving accuracy as an audit tool. Ensuring that RTs adhere to the audit process remains the challenge for the new system, and is the rate-limiting step.

Acoustic phenomena observed in lung auscultation

NASA Astrophysics Data System (ADS)

Korenbaum, V. I.; Tagil'Tsev, A. A.; Kulakov, Yu. V.

2003-05-01

The results of studying respiratory noise at the chest wall by the method of acoustic intensimetry reveal the presence of frequency components with different signs of the real and imaginary parts of the cross spectrum obtained for the responses of the receivers of vibratory displacement and dynamic force. An acoustic model is proposed to explain this difference on the basis of the hypothesis that the contributions of both air-borne and structure-borne sound are significant in the transmission of respiratory noise to the chest wall. It is shown that, when considered as an acoustic channel for the basic respiratory noise, the respiratory system of an adult subject has two resonances: in the frequency bands within 110 150 and 215 350 Hz. For adults in normal condition, the air-borne component of the basic respiratory noise predominates in the region 100 300 Hz in the lower parts of lungs. At forced respiration of healthy adults, the sounds of vesicular respiration are generated by the turbulent air flow in the 11th-through 13th-generation bronchi, and the transmission of these sounds to the chest wall in normal condition is mainly through air and is determined by the resonance of the vibratory system formed by the elasticity of air in the respiratory ducts of lungs and by the surface mass density of the chest wall. It is demonstrated that the distance from the chest wall to the sources of structure-borne additional respiratory noise, namely, wheezing with frequencies above 300 Hz, can be estimated numerically from the ratio between the real and imaginary parts of the cross spectrum on the assumption that the source is of the quadrupole type.

Locomotor-respiratory coupling patterns and oxygen consumption during walking above and below preferred stride frequency.

PubMed

O'Halloran, Joseph; Hamill, Joseph; McDermott, William J; Remelius, Jebb G; Van Emmerik, Richard E A

2012-03-01

Locomotor respiratory coupling patterns in humans have been assessed on the basis of the interaction between different physiological and motor subsystems; these interactions have implications for movement economy. A complex and dynamical systems framework may provide more insight than entrainment into the variability and adaptability of these rhythms and their coupling. The purpose of this study was to investigate the relationship between steady state locomotor-respiratory coordination dynamics and oxygen consumption [Formula: see text] of the movement by varying walking stride frequency from preferred. Twelve male participants walked on a treadmill at a self-selected speed. Stride frequency was varied from -20 to +20% of preferred stride frequency (PSF) while respiratory airflow, gas exchange variables, and stride kinematics were recorded. Discrete relative phase and return map techniques were used to evaluate the strength, stability, and variability of both frequency and phase couplings. Analysis of [Formula: see text] during steady-state walking showed a U-shaped response (P = 0.002) with a minimum at PSF and PSF - 10%. Locomotor-respiratory frequency coupling strength was not greater (P = 0.375) at PSF than any other stride frequency condition. The dominant coupling across all conditions was 2:1 with greater occurrences at the lower stride frequencies. Variability in coupling was the greatest during PSF, indicating an exploration of coupling strategies to search for the coupling frequency strategy with the least oxygen consumption. Contrary to the belief that increased strength of frequency coupling would decrease oxygen consumption; these results conclude that it is the increased variability of frequency coupling that results in lower oxygen consumption.

Breathing is affected by dopamine D2-like receptors in the basolateral amygdala.

PubMed

Sugita, Toshihisa; Kanamaru, Mitsuko; Iizuka, Makito; Sato, Kanako; Tsukada, Setsuro; Kawamura, Mitsuru; Homma, Ikuo; Izumizaki, Masahiko

2015-04-01

The precise mechanisms underlying how emotions change breathing patterns remain unclear, but dopamine is a candidate neurotransmitter in the process of emotion-associated breathing. We investigated whether basal dopamine release occurs in the basolateral amygdala (BLA), where sensory-related inputs are received and lead to fear or anxiety responses, and whether D1- and D2-like receptor antagonists affect breathing patterns and dopamine release in the BLA. Adult male mice (C57BL/6N) were perfused with artificial cerebrospinal fluid, a D1-like receptor antagonist (SCH 23390), or a D2-like receptor antagonist ((S)-(-)-sulpiride) through a microdialysis probe in the BLA. Respiratory variables were measured using a double-chamber plethysmograph. Dopamine release was measured by an HPLC. Perfusion of (S)-(-)-sulpiride in the BLA, not SCH 23390, specifically decreased respiratory rate without changes in local release of dopamine. These results suggest that basal dopamine release in the BLA, at least partially, increases respiratory rates only through post-synaptic D2-like receptors, not autoreceptors, which might be associated with emotional responses. Copyright © 2014 Elsevier B.V. All rights reserved.

Vocal fold contact patterns based on normal modes of vibration.

PubMed

Smith, Simeon L; Titze, Ingo R

2018-05-17

The fluid-structure interaction and energy transfer from respiratory airflow to self-sustained vocal fold oscillation continues to be a topic of interest in vocal fold research. Vocal fold vibration is driven by pressures on the vocal fold surface, which are determined by the shape of the glottis and the contact between vocal folds. Characterization of three-dimensional glottal shapes and contact patterns can lead to increased understanding of normal and abnormal physiology of the voice, as well as to development of improved vocal fold models, but a large inventory of shapes has not been directly studied previously. This study aimed to take an initial step toward characterizing vocal fold contact patterns systematically. Vocal fold motion and contact was modeled based on normal mode vibration, as it has been shown that vocal fold vibration can be almost entirely described by only the few lowest order vibrational modes. Symmetric and asymmetric combinations of the four lowest normal modes of vibration were superimposed on left and right vocal fold medial surfaces, for each of three prephonatory glottal configurations, according to a surface wave approach. Contact patterns were generated from the interaction of modal shapes at 16 normalized phases during the vibratory cycle. Eight major contact patterns were identified and characterized by the shape of the flow channel, with the following descriptors assigned: convergent, divergent, convergent-divergent, uniform, split, merged, island, and multichannel. Each of the contact patterns and its variation are described, and future work and applications are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhanced glucocorticoid-induced leucine zipper in dendritic cells induces allergen-specific regulatory CD4(+) T-cells in respiratory allergies.

PubMed

Karaki, S; Garcia, G; Tcherakian, C; Capel, F; Tran, T; Pallardy, M; Humbert, M; Emilie, D; Godot, V

2014-05-01

Respiratory allergies rely on a defect of IL-10-secreting regulatory CD4(+) T-cells (IL-10-Tregs ) leading to excessive Th2-biased immune responses to allergens. According to clinical data, the restoration of allergen-specific IL-10-Tregs is required to control respiratory allergies and cure patients. The discovery of mechanisms involved in the generation of IL-10-Tregs will thus help to provide effective treatments. We previously demonstrated that dendritic cells (DCs) expressing high levels of the glucocorticoid-induced leucine zipper protein (GILZ) generate antigen-specific IL-10-Tregs . We suspect a defective expression of GILZ in the DCs of respiratory allergic patients and speculate that increasing its expression might restore immune tolerance against allergens through the induction of IL-10-Tregs . We assessed GILZ expression in blood DCs of patients and healthy nonallergic donors by qPCR. We compared the ability of patients' DCs to induce allergen-specific IL-10-Tregs before and after an in vivo up-regulation of GILZ expression by steroid administration, steroids being inducers of GILZ. We report lower levels of GILZ in DCs of respiratory allergic patients that return to normal levels after steroid administration. We show that patients' DCs with increased levels of GILZ generate allergen-specific IL-10-Tregs again. We further confirm unequivocally that GILZ is required in patients' DCs to activate these IL-10-Tregs . This proof of concept study shows that the re-establishment of GILZ expression in patients' DCs to normal levels restores their capacity to activate allergen-specific IL-10-Tregs . We thus highlight the up-regulation of GILZ in DCs as a new interventional approach to restore the immune tolerance to allergens. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of maturation and acidosis on the chaos-like complexity of the neural respiratory output in the isolated brainstem of the tadpole, Rana esculenta

PubMed Central

Samara, Ziyad; Fiamma, Marie-Noëlle; Bautin, Nathalie; Ranohavimparany, Anja; Le Coz, Patrick; Golmard, Jean-Louis; Darré, Pierre; Zelter, Marc; Poon, Chi-Sang; Similowski, Thomas

2011-01-01

Human ventilation at rest exhibits mathematical chaos-like complexity that can be described as long-term unpredictability mediated (in whole or in part) by some low-dimensional nonlinear deterministic process. Although various physiological and pathological situations can affect respiratory complexity, the underlying mechanisms remain incompletely elucidated. If such chaos-like complexity is an intrinsic property of central respiratory generators, it should appear or increase when these structures mature or are stimulated. To test this hypothesis, we employed the isolated tadpole brainstem model [Rana (Pelophylax) esculenta] and recorded the neural respiratory output (buccal and lung rhythms) of pre- (n = 8) and postmetamorphic tadpoles (n = 8), at physiologic (7.8) and acidic pH (7.4). We analyzed the root mean square of the cranial nerve V or VII neurograms. Development and acidosis had no effect on buccal period. Lung frequency increased with development (P < 0.0001). It also increased with acidosis, but in postmetamorphic tadpoles only (P < 0.05). The noise-titration technique evidenced low-dimensional nonlinearities in all the postmetamorphic brainstems, at both pH. Chaos-like complexity, assessed through the noise limit, increased from pH 7.8 to pH 7.4 (P < 0.01). In contrast, linear models best fitted the ventilatory rhythm in all but one of the premetamorphic preparations at pH 7.8 (P < 0.005 vs. postmetamorphic) and in four at pH 7.4 (not significant vs. postmetamorphic). Therefore, in a lower vertebrate model, the brainstem respiratory central rhythm generator accounts for ventilatory chaos-like complexity, especially in the postmetamorphic stage and at low pH. According to the ventilatory generators homology theory, this may also be the case in mammals. PMID:21325645

Effects of maturation and acidosis on the chaos-like complexity of the neural respiratory output in the isolated brainstem of the tadpole, Rana esculenta.

PubMed

Straus, Christian; Samara, Ziyad; Fiamma, Marie-Noëlle; Bautin, Nathalie; Ranohavimparany, Anja; Le Coz, Patrick; Golmard, Jean-Louis; Darré, Pierre; Zelter, Marc; Poon, Chi-Sang; Similowski, Thomas

2011-05-01

Human ventilation at rest exhibits mathematical chaos-like complexity that can be described as long-term unpredictability mediated (in whole or in part) by some low-dimensional nonlinear deterministic process. Although various physiological and pathological situations can affect respiratory complexity, the underlying mechanisms remain incompletely elucidated. If such chaos-like complexity is an intrinsic property of central respiratory generators, it should appear or increase when these structures mature or are stimulated. To test this hypothesis, we employed the isolated tadpole brainstem model [Rana (Pelophylax) esculenta] and recorded the neural respiratory output (buccal and lung rhythms) of pre- (n = 8) and postmetamorphic tadpoles (n = 8), at physiologic (7.8) and acidic pH (7.4). We analyzed the root mean square of the cranial nerve V or VII neurograms. Development and acidosis had no effect on buccal period. Lung frequency increased with development (P < 0.0001). It also increased with acidosis, but in postmetamorphic tadpoles only (P < 0.05). The noise-titration technique evidenced low-dimensional nonlinearities in all the postmetamorphic brainstems, at both pH. Chaos-like complexity, assessed through the noise limit, increased from pH 7.8 to pH 7.4 (P < 0.01). In contrast, linear models best fitted the ventilatory rhythm in all but one of the premetamorphic preparations at pH 7.8 (P < 0.005 vs. postmetamorphic) and in four at pH 7.4 (not significant vs. postmetamorphic). Therefore, in a lower vertebrate model, the brainstem respiratory central rhythm generator accounts for ventilatory chaos-like complexity, especially in the postmetamorphic stage and at low pH. According to the ventilatory generators homology theory, this may also be the case in mammals.

Understanding the transmission dynamics of respiratory syncytial virus using multiple time series and nested models.

PubMed

White, L J; Mandl, J N; Gomes, M G M; Bodley-Tickell, A T; Cane, P A; Perez-Brena, P; Aguilar, J C; Siqueira, M M; Portes, S A; Straliotto, S M; Waris, M; Nokes, D J; Medley, G F

2007-09-01

The nature and role of re-infection and partial immunity are likely to be important determinants of the transmission dynamics of human respiratory syncytial virus (hRSV). We propose a single model structure that captures four possible host responses to infection and subsequent reinfection: partial susceptibility, altered infection duration, reduced infectiousness and temporary immunity (which might be partial). The magnitude of these responses is determined by four homotopy parameters, and by setting some of these parameters to extreme values we generate a set of eight nested, deterministic transmission models. In order to investigate hRSV transmission dynamics, we applied these models to incidence data from eight international locations. Seasonality is included as cyclic variation in transmission. Parameters associated with the natural history of the infection were assumed to be independent of geographic location, while others, such as those associated with seasonality, were assumed location specific. Models incorporating either of the two extreme assumptions for immunity (none or solid and lifelong) were unable to reproduce the observed dynamics. Model fits with either waning or partial immunity to disease or both were visually comparable. The best fitting structure was a lifelong partial immunity to both disease and infection. Observed patterns were reproduced by stochastic simulations using the parameter values estimated from the deterministic models.

Memory, reconsolidation and extinction in Lymnaea require the soma of RPeD1.

PubMed

Sangha, Susan; Varshney, Nishi; Fras, Mary; Smyth, Kim; Rosenegger, David; Parvez, Kashif; Sadamoto, Hisayo; Lukowiak, Ken

2004-01-01

The central pattern generator (CPG) that drives aerial respiratory behaviour in Lymnaea consists of 3 neurons. One of these, RPeD1--the cell that initiates activity in the circuit, plays an absolutely necessary role as a site for memory formation, memory reconsolidation, and extinction. Using an operant conditioning training procedure that results in a long-term non-declarative memory (LTM), we decrease the occurrence of aerial respiratory behaviour. Since snails can still breathe cutaneously learning this procedure is not harmful. Concomitant with behavioural memory are changes in the spiking activity of RPeD1. Going beyond neural correlates of memory we directly show that RPeD1 is a necessary site for LTM formation. Expanding on this finding we show that this neuron is also a necessary site for memory reconsolidation and 'Pavlovian' extinction. As far as we can determine, this is the first time a single neuron has been shown to be a necessary site for these different aspects memory. RPeD1 is thus a key neuron mediating different hierarchical aspects of memory. We are now in a position to determine the necessary neuronal, molecular and proteomic events in this neuron that are causal to memory formation, reconsolidation and extinction.

A molluscan model system in the search for the engram.

PubMed

Lukowiak, Ken; Sangha, Susan; Scheibenstock, Andi; Parvez, Kashif; McComb, Chloe; Rosenegger, David; Varshney, Nishi; Sadamoto, Hisayo

2003-01-01

A 3-neuron central pattern generator, whose sufficiency and necessity has been directly demonstrated, mediates aerial respiratory behaviour in the pond snail, Lymnaea stagnalis. This behaviour can be operantly conditioned, and this associative learning is consolidated into long-lasting memory. Depending on the operant conditioning training procedure used the learning can be consolidated into intermediate term (ITM) or long-term memory (LTM). ITM persists for only 2-3 h, whilst LTM persists for days to weeks. LTM is dependent on both altered gene activity and new protein synthesis while ITM is only dependent on new protein synthesis. We have now directly established that one of the 3-CPG neurons, RPeD1, is a site of LTM formation and storage. We did this by ablating the soma of RPeD1 and leaving behind a functional primary neurite capable of mediating the necessary synaptic interactions to drive aerial respiratory behaviour by the 3-neuron CPG. However, following soma ablation the neuronal circuit is only capable of mediating learning and ITM. LTM can no longer be demonstrated. However, if RPeD1's soma is ablated after LTM consolidation memory is still present. Thus the soma is not needed for the retention of LTM. Using a similar strategy it may be possible to block forgetting.

Modulation of Respiratory Frequency by Peptidergic Input to Rhythmogenic Neurons in the PreBötzinger Complex

PubMed Central

Gray, Paul A.; Rekling, Jens C.; Bocchiaro, Christopher M.; Feldman, Jack L.

2010-01-01

Neurokinin-1 receptor (NK1R) and μ-opioid receptor (μOR) agonists affected respiratory rhythm when injected directly into the preBötzinger Complex (preBötC), the hypothesized site for respiratory rhythmogenesis in mammals. These effects were mediated by actions on preBötC rhythmogenic neurons. The distribution of NK1R+ neurons anatomically defined the preBötC. Type 1 neurons in the preBötC, which have rhythmogenic properties, expressed both NK1Rs and μORs, whereas type 2 neurons expressed only NK1Rs. These findings suggest that the preBötC is a definable anatomic structure with unique physiological function and that a subpopulation of neurons expressing both NK1Rs and μORs generate respiratory rhythm and modulate respiratory frequency. PMID:10567264

Cardiovascular activity in blood-injection-injury phobia during exposure: evidence for diphasic response patterns?

PubMed

Ritz, Thomas; Meuret, Alicia E; Simon, Erica

2013-08-01

Exposure to feared stimuli in blood-injection-injury (BII)-phobia is thought to elicit a diphasic response pattern, with an initial fight-flight-like cardiovascular activation followed by a marked deactivation and possible fainting (vasovagal syncope). However, studies have remained equivocal on the importance of such patterns. We therefore sought to determine the prevalence and clinical relevance of diphasic responses using criteria that require a true diphasic response to exceed cardiovascular activation of an emotional episode of a negative valence and to exceed deactivation of an emotionally neutral episode. Sixty BII-phobia participants and 20 healthy controls were exposed to surgery, anger and neutral films while measuring heart rate, blood pressure, respiratory pattern, and end-tidal partial pressure of carbon dioxide (as indicator of hyperventilation). Diphasic response patterns were observed in up to 20% of BII-phobia participants and 26.6% of healthy controls for individual cardiovascular parameters. BII-phobia participants with diphasic patterns across multiple parameters showed more fear of injections and blood draws, reported the strongest physical symptoms during the surgery film, and showed the strongest tendency to hyperventilate. Thus, although only a minority of individuals with BII phobia shows diphasic responses, their occurrence indicates significant distress. Respiratory training may add to the treatment of BII phobia patients that show diphasic response patterns. Copyright © 2013 Elsevier Ltd. All rights reserved.

Vaccine-associated enhanced respiratory disease does not interfere with the adaptive immune response following challenge with pandemic A/H1N1 2009

USDA-ARS?s Scientific Manuscript database

Background. The implications of sequential prime and challenge with mismatched influenza A viruses is a concern in mammals including humans. We evaluated the ability of pigs affected with vaccine associated enhanced respiratory disease (VAERD) to generate a humoral immune response against the hetero...

Pharmacology of o-chlorobenzylidene malononitrile (CS)

PubMed Central

Brimblecombe, R. W.; Green, D. M.; Muir, A. W.

1972-01-01

1. The effects of o-chlorobenzylidene malononitrile (CS) have been studied on several isolated organs and tissues, anaesthetized animals and cat encéphale isolé preparations. 2. On the isolated guinea-pig ileum an initial dose of CS produced a small, non-maintained contraction. Subsequent doses had reduced effects. There was no effect on peristalsis when the substance was given intraluminally. 3. No significant effects of CS were detected on the rat phrenic nerve-diaphragm preparation, the isolated perfused rabbit heart or on the contractor response of the indirectly stimulated cat tibialis muscle. 4. In the cat encéphale isolé preparation 1 mg/kg (i.v.) produced a brief period of electrocortical alerting but no abnormal activity in the electrocorticogram. Doses in excess of 10 mg/kg produced cortical depression. 5. Intravascular injection into the chloralose anaesthetized cat resulted typically in a pressor response accompanied by a brief period of apnoea. The threshold dose for the pressor response varied with the route of administration, but generally lay between 2·5 and 12·5 μg/kg; the threshold dose for apnoea was slightly higher. Small variations in this pattern of response were seen with different species and other anaesthetics. 6. When administered by stomach tube to chloralose anaesthetized cats, CS produced no measurable effects at doses of up to 100 mg/kg. 7. No changes in blood pressure or respiration were detected in anaesthetized cats given pure CS aerosol for 1 h in concentrations of between 345 mg/m3 and 1·39 g/m3 via a tracheal cannula or through the upper respiratory tract. Pure CS solution given by slow intravenous infusion at a similar dose and over a similar period produced significant effects on blood pressure and respiration. 8. Pyrotechnically generated (grenade) CS produced variable effects when given by inhalation in concentrations of between 460 and 1,040 mg/m3 for 1 hour. Respiratory depression, possibly reflex in nature, regularly occurred when the material was given via the upper respiratory tract, and respiratory stimulation occurred when it was given via a tracheal cannula. 9. Some cats were pre-exposed to a dose of 500 (mg/min)/m3 on 4 successive days and on the fifth day anaesthetized and exposed to high concentrations of grenade CS. Three out of six cats died during or after this final exposure compared to one out of six among animals not so pre-exposed. The general pattern of response to the final exposure to CS in the two groups was similar. PMID:5040666

Theoretical analysis of the influence of aerosol size distribution and physical activity on particle deposition pattern in human lungs.

PubMed

Voutilainen, Arto; Kaipio, Jari P; Pekkanen, Juha; Timonen, Kirsi L; Ruuskanen, Juhani

2004-01-01

A theoretical comparison of modeled particle depositions in the human respiratory tract was performed by taking into account different particle number and mass size distributions and physical activity in an urban environment. Urban-air data on particulate concentrations in the size range 10 nm-10 microm were used to estimate the hourly average particle number and mass size distribution functions. The functions were then combined with the deposition probability functions obtained from a computerized ICRP 66 deposition model of the International Commission on Radiological Protection to calculate the numbers and masses of particles deposited in five regions of the respiratory tract of a male adult. The man's physical activity and minute ventilation during the day were taken into account in the calculations. Two different mass and number size distributions of aerosol particles with equal (computed) <10 microm particle mass concentrations gave clearly different deposition patterns in the central and peripheral regions of the human respiratory tract. The deposited particle numbers and masses were much higher during the day (0700-1900) than during the night (1900-0700) because an increase in physical activity and ventilation were temporally associated with highly increased traffic-derived particles in urban outdoor air. In future analyses of the short-term associations between particulate air pollution and health, it would not only be important to take into account the outdoor-to-indoor penetration of different particle sizes and human time-activity patterns, but also actual lung deposition patterns and physical activity in significant microenvironments.

The Structure Design of Piezoelectric Poly(vinylidene Fluoride) (PVDF) Polymer-Based Sensor Patch for the Respiration Monitoring under Dynamic Walking Conditions.

PubMed

Lei, Kin-Fong; Hsieh, Yi-Zheng; Chiu, Yi-Yuan; Wu, Min-Hsien

2015-07-31

This study reports a piezoelectric poly(vinylidene fluoride) (PVDF) polymer-based sensor patch for respiration detections in dynamic walking condition. The working mechanism of respiration signal generation is based on the periodical deformations on a human chest wall during the respiratory movements, which in turn mechanically stretch the piezoelectric PVDF film to generate the corresponding electrical signals. In this study, the PVDF sensing film was completely encapsulated within the sensor patch forming a mass-spring-damper mechanical system to prevent the noises generated in a dynamic condition. To verify the design of sensor patch to prevent dynamic noises, experimental investigations were carried out. Results demonstrated the respiration signals generated and the respiratory rates measured by the proposed sensor patch were in line with the same measurements based on a commercial respiratory effort transducer both in a static (e.g., sitting) or dynamic (e.g., walking) condition. As a whole, this study has developed a PVDF-based sensor patch which is capable of monitoring respirations in a dynamic walking condition with high fidelity. Other distinctive features include its small size, light weight, ease of use, low cost, and portability. All these make it a promising sensing device to monitor respirations particularly in home care units.

Effect of nicotine, cotinine and cigarette smoke extract on the neutrophil respiratory burst.

PubMed

Matthews, John B; Chen, Fa-Ming; Milward, Michael R; Wright, Helen J; Carter, Kevin; McDonagh, Anna; Chapple, Iain L C

2011-03-01

To determine the effect of nicotine, cotinine and cigarette smoke extract (CSE) on the neutrophil respiratory burst and their effect on activation of the nuclear factor-κB (NFκB) pathway in oral epithelium. Neutrophils from periodontally healthy individuals were treated with nicotine, cotinine and CSE before stimulation with Fusobacterium nucleatum, IgG-opsonized Staphylococcus aureus and Escherichia coli lipopolysaccharide. Total and extracellular reactive oxygen species (ROS) generation was determined by luminol/isoluminol chemiluminescence. Activation of NFκB in oral epithelial cells was determined by immunocytochemistry. Smoke extract alone caused increased neutrophil extracellular isoluminol-dependent chemiluminescence, not detectable with luminol. However, pre-treatment with smoke extract reduced both total and extracellular ROS generation in response to all stimuli. Nicotine and cotinine had no effect on the neutrophil respiratory burst. Smoke extract, nicotine and cotinine did not induce oral epithelial cell NFκB activation. These data demonstrate that smoke extract reduces the ability of neutrophils to generate ROS after stimulation with F. nucleatum and IgG-opsonized S. aureus but, at high concentrations, stimulates extracellular ROS generation. During periodontitis, cigarette smoking may differentially affect neutrophil function, generally preventing elimination of periodontal pathogens but, in heavy smokers, also stimulating ROS release and oxidative stress mediated tissue damage. © 2011 John Wiley & Sons A/S.

Relationship of plasma N-terminal pro-brain natriuretic peptide concentrations to heart failure classification and cause of respiratory distress in dogs using a 2nd generation ELISA assay.

PubMed

Fox, P R; Oyama, M A; Hezzell, M J; Rush, J E; Nguyenba, T P; DeFrancesco, T C; Lehmkuhl, L B; Kellihan, H B; Bulmer, B; Gordon, S G; Cunningham, S M; MacGregor, J; Stepien, R L; Lefbom, B; Adin, D; Lamb, K

2015-01-01

Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD). Determine the utility of plasma N-terminal pro-brain natriuretic peptide concentration [NT-proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity. Client-owned dogs (n = 291). Multicenter, cross-sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM-HD) schemes without knowledge of [NT-proBNP] results. Receiver-operating characteristic curve analysis assessed the capacity of [NT-proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT-proBNP] and HD severity. Plasma [NT-proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769-8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672-2,704 pmol/L; P < .0001). A cut-off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end-systole, and ACVIM-HD scheme most accurately associated average plasma [NT-proBNP] with HD severity. Plasma [NT-proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT-BNP] increased significantly as a function of HD severity using the ACVIM-HD classification scheme. Copyright © 2014 by the American College of Veterinary Internal Medicine.

Realistic respiratory motion margins for external beam partial breast irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Leigh; Quirk, Sarah; Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4

Purpose: Respiratory margins for partial breast irradiation (PBI) have been largely based on geometric observations, which may overestimate the margin required for dosimetric coverage. In this study, dosimetric population-based respiratory margins and margin formulas for external beam partial breast irradiation are determined. Methods: Volunteer respiratory data and anterior–posterior (AP) dose profiles from clinical treatment plans of 28 3D conformal radiotherapy (3DCRT) PBI patient plans were used to determine population-based respiratory margins. The peak-to-peak amplitudes (A) of realistic respiratory motion data from healthy volunteers were scaled from A = 1 to 10 mm to create respiratory motion probability density functions. Dosemore » profiles were convolved with the respiratory probability density functions to produce blurred dose profiles accounting for respiratory motion. The required margins were found by measuring the distance between the simulated treatment and original dose profiles at the 95% isodose level. Results: The symmetric dosimetric respiratory margins to cover 90%, 95%, and 100% of the simulated treatment population were 1.5, 2, and 4 mm, respectively. With patient set up at end exhale, the required margins were larger in the anterior direction than the posterior. For respiratory amplitudes less than 5 mm, the population-based margins can be expressed as a fraction of the extent of respiratory motion. The derived formulas in the anterior/posterior directions for 90%, 95%, and 100% simulated population coverage were 0.45A/0.25A, 0.50A/0.30A, and 0.70A/0.40A. The differences in formulas for different population coverage criteria demonstrate that respiratory trace shape and baseline drift characteristics affect individual respiratory margins even for the same average peak-to-peak amplitude. Conclusions: A methodology for determining population-based respiratory margins using real respiratory motion patterns and dose profiles in the AP direction was described. It was found that the currently used respiratory margin of 5 mm in partial breast irradiation may be overly conservative for many 3DCRT PBI patients. Amplitude alone was found to be insufficient to determine patient-specific margins: individual respiratory trace shape and baseline drift both contributed to the dosimetric target coverage. With respiratory coaching, individualized respiratory margins smaller than the full extent of motion could reduce planning target volumes while ensuring adequate coverage under respiratory motion.« less

[Computed tomographic semiotics of respiratory tuberculosis in HIV-infected patients].

PubMed

Gavrilov, P V; Lazareva, A S; Malashenkov, E A

2013-01-01

to study the computed tomographic (CT) semiotics of respiratory tuberculosis in HIV-infected patients in relation to the degree of immunosuppression. The study enrolled 74 patients with verified respiratory tuberculosis in the presence of HIV infection. According to the degree of immunosuppression and the Centers for Disease Control (CDC) and Prevention classification (Atlanta, USA, 1993), the patients were divided into 3 groups: (1) CD4 > or = 500 cells/microl (n = 10); 2) CD4 200-499 cells/microl (n = 28); (3) CD4 <200 cells/microl (n = 36). With spiral CT, focal changes with a predominance of clear-cut foci are visualized at a high frequency in the patients with pulmonary tuberculosis in the presence of HIV infection. In progressive immunosuppression, the CT pattern displays atypical syndromes (frosted glass-type foci, interstitial infiltration, and thin-walled cavities) with the lower rate of alveolar infiltration with confluent foci, as well as lung tissue decay. Enlarged intrathoracic lymph nodes are characteristic of 70.0% of the patients with HIV infection and tuberculosis regardless of the level of CD4 cells. As immunosuppression progresses, the CT pattern of respiratory tuberculosis in the presence of HIV infection shows as atypical syndromes (unclearly defined frosted glass-type focal changes, interstitial infiltrations, and thin-walled cavernous masses). A marked polymorphism in changes and a high rate of lymph node involvement are characteristic.

Asian Dust Storm Elevates Children’s Respiratory Health Risks: A Spatiotemporal Analysis of Children’s Clinic Visits across Taipei (Taiwan)

PubMed Central

Yu, Hwa-Lung; Chien, Lung-Chang; Yang, Chiang-Hsing

2012-01-01

Concerns have been raised about the adverse impact of Asian dust storms (ADS) on human health; however, few studies have examined the effect of these events on children’s health. Using databases from the Taiwan National Health Insurance and Taiwan Environmental Protection Agency, this study investigates the documented daily visits of children to respiratory clinics during and after ADS that occurred from 1997 to 2007 among 12 districts across Taipei City by applying a Bayesian structural additive regressive model controlled for spatial and temporal patterns. This study finds that the significantly impact of elevated children’s respiratory clinic visits happened after ADS. Five of the seven lagged days had increasing percentages of relative rate, which was consecutively elevated from a 2-day to a 5-day lag by 0.63%∼2.19% for preschool children (i.e., 0∼6 years of age) and 0.72%∼3.17% for school children (i.e., 7∼14 years of age). The spatial pattern of clinic visits indicated that geographical heterogeneity was possibly associated with the clinic’s location and accessibility. Moreover, day-of-week effects were elevated on Monday, Friday, and Saturday. We concluded that ADS may significantly increase the risks of respiratory diseases consecutively in the week after exposure, especially in school children. PMID:22848461

Social contact patterns of infants in deciding vaccination strategy: a prospective, cross-sectional, single-centre study.

PubMed

Oguz, M M; Camurdan, A D; Aksakal, F N; Akcaboy, M; Altinel Acoglu, E

2018-05-09

Social contact between individuals is believed to be a fundamental cause in the transmission of many respiratory tract infections. Because they have not yet been fully vaccinated, infants are at high risk for contracting whooping cough, influenza and their serious complications. Therefore, determining infant social contact patterns is an important step in protecting them from respiratory tract infection. This study included 1200 healthy infants (<12 months of age). Social contact diaries were used to estimate the frequency and nature of the infants' social contacts. This survey also gathered information regarding the infants' respiratory symptoms and their frequency of attendance at crowded places over a period of 1 week. The diary return rate was 83.8% (N = 1006), and there was a total of 4706 contacts reported for these infants. The median daily contact number per capita was 4 (range 1-18). The median number of contacts with adolescents was 0 (range 0-7). Of the infants, 50.3% had contact with non-household individuals. The mothers had the longest contacts with their babies. Contacts with school children, frequency of attendance at crowded places and age were determined to be significant effective factors for reporting respiratory symptoms. Results suggest that school-age siblings and the mothers should be primarily vaccinated, and parents should keep their babies away from crowded places for protecting their infants.

Influenza hospitalization epidemiology from a severe acute respiratory infection surveillance system in Jordan, January 2008-February 2014.

PubMed

Al-Abdallat, Mohammad; Dawson, Patrick; Haddadin, Aktham Jeries; El-Shoubary, Waleed; Dueger, Erica; Al-Sanouri, Tarek; Said, Mayar M; Talaat, Maha

2016-03-01

Acute respiratory infections (ARIs) are a major cause of morbidity and mortality worldwide. Influenza typically contributes substantially to the burden of ARI, but only limited data are available on influenza activity and seasonality in Jordan. Syndromic case definitions were used to identify individuals with severe acute respiratory infections (SARI) admitted to four sentinel hospitals in Jordan. Demographic and clinical data were collected. Nasopharyngeal and oropharyngeal swabs were tested for influenza using real-time reverse transcription polymerase chain reaction and typed as influenza A or B, with influenza A further subtyped. From January 2008-February 2014, 2891 SARI cases were tested for influenza, and 257 (9%) were positive. While 73% of all SARI cases were under 5 years of age, only 57% of influenza-positive cases were under 5 years of age. Eight (3%) influenza-positive cases died. An annual seasonal pattern of influenza activity was observed. The proportion of influenza-positive cases peaked during November-January (14-42%) in the non-pandemic years. Influenza is associated with substantial morbidity and mortality in Jordan. The seasonal pattern of influenza aligns with known Northern Hemisphere seasonality. Further characterization of the clinical and financial burden of influenza in Jordan will be critical in supporting decisions regarding disease control activities. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Changes of neurotransmitters in the brainstem of patients with respiratory-pattern disorders during childhood.

PubMed

Saito, Y; Ito, M; Ozawa, Y; Obonai, T; Kobayashi, Y; Washizawa, K; Ohsone, Y; Takami, T; Oku, K; Takashima, S

1999-06-01

We examined neuropathologically and immunohistochemically the respiratory centers in the brainstem of two patients with Joubert syndrome (JS), three patients with congenital central hypoventilation syndrome (CCHS) and a patient with apneustic breathing (prolonged inspiratory pause) due to unknown etiology. Immunoreactivity (IR) of tryptophan hydroxylase (TPH) was decreased in the dorsal raphe nuclei of two patients with JS compared with age-matched controls, as well as in two patients with Dandy-Walker malformation. The two JS patients showed vermian defect and elongated cerebellar peduncles, and peculiar vascularities in the midline of the whole brainstem were also noted in one of these patients. These findings, as a whole, confirm that the midline structures of brainstem are disordered both structurally and functionally in JS, conceivably resulting in respiratory patterns and psychomotor deficits. IR of serotonin 1A receptor showed no significant changes in the medulla oblongata of these patients, however. In the parabrachial complex, IR of substance P was increased in two patients with CCHS, and one with apneustic breathing. IR of tyrosine hydroxylase was also increased in the latter. The brainstem of these patients showed reactive astrogliosis. These findings suggest preceding hypoxic episodes as well as an increased activity in the parabrachial complex which plays an important role in conducting the driving force to the medullary respiratory neurons from ascending sensory pathways.

Effects of breathing maneuver and sitting posture on muscle activity in inspiratory accessory muscles in patients with chronic obstructive pulmonary disease

PubMed Central

2012-01-01

Background To determine the influence of breathing maneuver and sitting posture on tidal volume (TV), respiratory rate (RR), and muscle activity of the inspiratory accessory muscles in patients with chronic obstructive pulmonary disease (COPD). Methods Twelve men with COPD participated in the study. Inductive respiratory plethysmography and surface electromyography were used to simultaneously measure TV, RR, and muscle activity of the inspiratory accessory muscles [the scalenus (SM), sternocleidomastoid (SCM), and pectoralis major (PM) muscles] during quiet natural breathing (QB) and pursed-lips breathing (PLB) in three sitting postures: neutral position (NP), with armm support (WAS), and with arm and head support (WAHS). Results Two-way repeated-measures analysis of variance was employed. In a comparison of breathing patterns, PLB significantly increased TV and decreased RR compared to QB. Muscle activity in the SM and SCM increased significantly in PLB compared to QB. In a comparison of sitting postures, the muscle activity of the SM, SCM, and PM increased in the forward-leaning position. Conclusions The results suggest that in COPD, PLB induced a favorable breathing pattern (increased TV and reduced RR) compared to QB. Additionally, WAS and WAHS positions increased muscle activity of the inspiratory accessory muscles during inspiration versus NP. Differential involvement of accessory respiratory muscles can be readily studied in COPD patients, allowing monitoring of respiratory load during pulmonary rehabilitation. PMID:22958459

Respiratory chain supercomplexes associate with the cysteine desulfurase complex of the iron–sulfur cluster assembly machinery

PubMed Central

Böttinger, Lena; Mårtensson, Christoph U.; Song, Jiyao; Zufall, Nicole; Wiedemann, Nils; Becker, Thomas

2018-01-01

Mitochondria are the powerhouses of eukaryotic cells. The activity of the respiratory chain complexes generates a proton gradient across the inner membrane, which is used by the F1FO-ATP synthase to produce ATP for cellular metabolism. In baker’s yeast, Saccharomyces cerevisiae, the cytochrome bc1 complex (complex III) and cytochrome c oxidase (complex IV) associate in respiratory chain supercomplexes. Iron–sulfur clusters (ISC) form reactive centers of respiratory chain complexes. The assembly of ISC occurs in the mitochondrial matrix and is essential for cell viability. The cysteine desulfurase Nfs1 provides sulfur for ISC assembly and forms with partner proteins the ISC-biogenesis desulfurase complex (ISD complex). Here, we report an unexpected interaction of the active ISD complex with the cytochrome bc1 complex and cytochrome c oxidase. The individual deletion of complex III or complex IV blocks the association of the ISD complex with respiratory chain components. We conclude that the ISD complex binds selectively to respiratory chain supercomplexes. We propose that this molecular link contributes to coordination of iron–sulfur cluster formation with respiratory activity. PMID:29386296

Expression of the transcription factor FOXP2 in brainstem respiratory circuits of adult rat is restricted to upper-airway pre-motor areas.

PubMed

Stanić, Davor; Dhingra, Rishi R; Dutschmann, Mathias

2018-04-01

Expression of the transcription factor FOXP2 is linked to brain circuits that control motor function and speech. Investigation of FOXP2 protein expression in respiratory areas of the ponto-medullary brainstem of adult rat revealed distinct rostro-caudal expression gradients. A high density of FOXP2 immunoreactive nuclei was observed within the rostral pontine Kölliker-Fuse nucleus, compared to low densities in caudal pontine and rostral medullary respiratory nuclei, including the: (i) noradrenergic A5 and parafacial respiratory groups; (ii) Bötzinger and pre-Bötzinger complex and; (iii) rostral ventral respiratory group. Moderate densities of FOXP2 immunoreactive nuclei were observed in the caudal ventral respiratory group and the nucleus retroambiguus, with significant density levels found in the caudal half of the dorsal respiratory group and the hypoglossal pre-motor area lateral around calamus scriptorius. FOXP2 immunoreactivity was absent in all cranial nerve motor nuclei. We conclude that FOXP2 expression in respiratory brainstem areas selectively delineates laryngeal and hypoglossal pre-motor neuron populations essential for the generation of sound and voice. Copyright © 2018 Elsevier B.V. All rights reserved.

Pediatric acute respiratory distress syndrome: definition, incidence, and epidemiology: proceedings from the Pediatric Acute Lung Injury Consensus Conference.

PubMed

Khemani, Robinder G; Smith, Lincoln S; Zimmerman, Jerry J; Erickson, Simon

2015-06-01

Although there are similarities in the pathophysiology of acute respiratory distress syndrome in adults and children, pediatric-specific practice patterns, comorbidities, and differences in outcome necessitate a pediatric-specific definition. We sought to create such a definition. A subgroup of pediatric acute respiratory distress syndrome investigators who drafted a pediatric-specific definition of acute respiratory distress syndrome based on consensus opinion and supported by detailed literature review tested elements of the definition with patient data from previously published investigations. International PICUs. Children enrolled in published investigations of pediatric acute respiratory distress syndrome. None. Several aspects of the proposed pediatric acute respiratory distress syndrome definition align with the Berlin Definition of acute respiratory distress syndrome in adults: timing of acute respiratory distress syndrome after a known risk factor, the potential for acute respiratory distress syndrome to coexist with left ventricular dysfunction, and the importance of identifying a group of patients at risk to develop acute respiratory distress syndrome. There are insufficient data to support any specific age for "adult" acute respiratory distress syndrome compared with "pediatric" acute respiratory distress syndrome. However, children with perinatal-related respiratory failure should be excluded from the definition of pediatric acute respiratory distress syndrome. Larger departures from the Berlin Definition surround 1) simplification of chest imaging criteria to eliminate bilateral infiltrates; 2) use of pulse oximetry-based criteria when PaO2 is unavailable; 3) inclusion of oxygenation index and oxygen saturation index instead of PaO2/FIO2 ratio with a minimum positive end-expiratory pressure level for invasively ventilated patients; 4) and specific inclusion of children with preexisting chronic lung disease or cyanotic congenital heart disease. This pediatric-specific definition for acute respiratory distress syndrome builds on the adult-based Berlin Definition, but has been modified to account for differences between adults and children with acute respiratory distress syndrome. We propose using this definition for future investigations and clinical care of children with pediatric acute respiratory distress syndrome and encourage external validation with the hope for continued iterative refinement of the definition.

Thermal noise variance of a receive radiofrequency coil as a respiratory motion sensor.

PubMed

Andreychenko, A; Raaijmakers, A J E; Sbrizzi, A; Crijns, S P M; Lagendijk, J J W; Luijten, P R; van den Berg, C A T

2017-01-01

Development of a passive respiratory motion sensor based on the noise variance of the receive coil array. Respiratory motion alters the body resistance. The noise variance of an RF coil depends on the body resistance and, thus, is also modulated by respiration. For the noise variance monitoring, the noise samples were acquired without and with MR signal excitation on clinical 1.5/3 T MR scanners. The performance of the noise sensor was compared with the respiratory bellow and with the diaphragm displacement visible on MR images. Several breathing patterns were tested. The noise variance demonstrated a periodic, temporal modulation that was synchronized with the respiratory bellow signal. The modulation depth of the noise variance resulting from the respiration varied between the channels of the array and depended on the channel's location with respect to the body. The noise sensor combined with MR acquisition was able to detect the respiratory motion for every k-space read-out line. Within clinical MR systems, the respiratory motion can be detected by the noise in receive array. The noise sensor does not require careful positioning unlike the bellow, any additional hardware, and/or MR acquisition. Magn Reson Med 77:221-228, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Mechanical Properties of Respiratory Muscles

PubMed Central

Sieck, Gary C.; Ferreira, Leonardo F.; Reid, Michael B.; Mantilla, Carlos B.

2014-01-01

Striated respiratory muscles are necessary for lung ventilation and to maintain the patency of the upper airway. The basic structural and functional properties of respiratory muscles are similar to those of other striated muscles (both skeletal and cardiac). The sarcomere is the fundamental organizational unit of striated muscles and sarcomeric proteins underlie the passive and active mechanical properties of muscle fibers. In this respect, the functional categorization of different fiber types provides a conceptual framework to understand the physiological properties of respiratory muscles. Within the sarcomere, the interaction between the thick and thin filaments at the level of cross-bridges provides the elementary unit of force generation and contraction. Key to an understanding of the unique functional differences across muscle fiber types are differences in cross-bridge recruitment and cycling that relate to the expression of different myosin heavy chain isoforms in the thick filament. The active mechanical properties of muscle fibers are characterized by the relationship between myoplasmic Ca2+ and cross-bridge recruitment, force generation and sarcomere length (also cross-bridge recruitment), external load and shortening velocity (cross-bridge cycling rate), and cross-bridge cycling rate and ATP consumption. Passive mechanical properties are also important reflecting viscoelastic elements within sarcomeres as well as the extracellular matrix. Conditions that affect respiratory muscle performance may have a range of underlying pathophysiological causes, but their manifestations will depend on their impact on these basic elemental structures. PMID:24265238

The transmission dynamics of groups A and B human respiratory syncytial virus (hRSV) in England & Wales and Finland: seasonality and cross-protection.

PubMed

White, L J; Waris, M; Cane, P A; Nokes, D J; Medley, G F

2005-04-01

Human respiratory syncytial virus (hRSV) transmission dynamics are inherently cyclical, and the observed genetic diversity (between groups A and B) also appears to have a repeating pattern. A key unknown is the extent to which genetic variants interact immunologically, and thus impact on epidemiology. We developed a novel mathematical model for hRSV transmission including seasonal forcing of incidence and temporary intra- and inter-group partial immunity. Simultaneous model fits to data from two locations (England & Wales, UK, and Turku, Finland) successfully reproduced the contrasting infection dynamics and group A/B dominance patterns. Parameter estimates are consistent with direct estimates. Differences in the magnitude and seasonal variation in contact rate between the two populations alone could account for the variation in dynamics between these populations. The A/B group dominance patterns are explained by reductions in susceptibility to and infectiousness of secondary homologous and heterologous infections. The consequences of the observed dynamic complexity are discussed.

Finger drop sign-Characteristic pattern of distal weakness in Guillain-Barré Syndrome: A case report and review of the literature.

PubMed

Chee, Yong Chuan; Ong, Beng Hooi

2018-01-01

Guillain-Barré Syndrome is an acquired acute autoimmune polyradiculoneuropathy that commonly presents with limb weakness and occasional cranial nerve, respiratory and autonomic involvement. Although the classic description of Guillain-Barré Syndrome is that of a demyelinating neuropathy with ascending weakness, predominant bilateral finger drop as presenting feature has rarely been reported. A characteristic pattern of weakness involving the extensor components of the fingers known as "finger drop sign" has been first described to be specific in acute motor axonal neuropathy form of Guillain-Barré Syndrome in the literature. We report a case of acute motor-sensory axonal neuropathy, which showed characteristic pattern of predominant finger extensor weakness, and provide a summary of all reported cases to date. While previous reports suggested that this is a sign that carries good prognosis, our case report suggested otherwise as the patient succumbed to respiratory and autonomic complications. Further studies are needed to evaluate the clinical significance of this peculiar sign.

Adenovirus type 4 respiratory infections with a concurrent outbreak of coxsackievirus A21 among United States Army Basic Trainees, a retrospective viral etiology study using next-generation sequencing.

PubMed

Hang, Jun; Vento, Todd J; Norby, Erica A; Jarman, Richard G; Keiser, Paul B; Kuschner, Robert A; Binn, Leonard N

2017-08-01

Human adenoviruses (HAdV), in particular types 4 and 7, frequently cause acute respiratory disease (ARD) during basic military training. HAdV4 and HAdV7 vaccines reduced the ARD risk in U.S. military. It is important to identify other respiratory pathogens and assess their potential impact on military readiness. In 2002, during a period when the HAdV vaccines were not available, throat swabs were taken from trainees (n = 184) with respiratory infections at Fort Jackson, South Carolina. Viral etiology was investigated initially with viral culture and neutralization assay and recently in this study by sequencing the viral isolates. Viral culture and neutralization assays identified 90 HAdV4 isolates and 27 additional cultures that showed viral cytopathic effects (CPE), including some with picornavirus-like CPE. Next-generation sequencing confirmed these results and determined viral genotypes, including 77 HAdV4, 4 HAdV3, 1 HAdV2, 17 coxsackievirus A21 (CAV21), and 1 enterovirus D68. Two samples were positive for both HAdV4 and CAV21. The identified genotypes are phylogenetically close to but distinct from those found during other years or in other military/non-military sites. HAdV4 is the predominant respiratory pathogen in unvaccinated military trainee. HAdV4 has temporal and demographic variability. CAV21 is a significant respiratory pathogen and needs to be evaluated for its current significance in military basic trainees. © 2017 Wiley Periodicals, Inc.

[Monitoring respiratory syncytial virus through the Spanish influenza surveillance system, 2006-2014].

PubMed

Jiménez-Jorge, Silvia; Delgado-Sanz, Concepción; de Mateo, Salvador; Pozo, Francisco; Casas, Inmaculada; Larrauri, Amparo

2016-02-01

The aim of the study is to analyze the information on respiratory syncytial virus (RSV) obtained through the Spanish Influenza Surveillance System (SISS) and to study its usefulness as supplementary information for the characterization of influenza epidemics. The temporal patterns of both RSV and influenza viruses were analyzed by patterns comparing the weekly viral detection rates from 2006 to 2014. In general, the RSV circulation was characterized by showing a peak between 52-1 weeks, and circulated from 2 to 8 weeks before/prior to influenza viruses. RSV information obtained from the SISS is useful for the characterization of influenza epidemics in Spain. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Respiratory monitoring by porphyrin modified quartz crystal microbalance sensors.

PubMed

Selyanchyn, Roman; Korposh, Serhiy; Wakamatsu, Shunichi; Lee, Seung-Woo

2011-01-01

A respiratory monitoring system based on a quartz crystal microbalance (QCM) sensor with a functional film was designed and investigated. Porphyrins 5,10,15,20-tetrakis-(4-sulfophenyl)-21H,23H-porphine (TSPP) and 5,10,15,20-tetrakis-(4-sulfophenyl)-21H, 23H-porphine manganese (III) chloride (MnTSPP) used as sensitive elements were assembled with a poly(diallyldimethyl ammonium chloride) (PDDA). Films were deposited on the QCM resonators using layer-by-layer method in order to develop the sensor. The developed system, in which the sensor response reflects lung movements, was able to track human respiration providing respiratory rate (RR) and respiratory pattern (RP). The sensor system was tested on healthy volunteers to compare RPs and calculate RRs. The operation principle of the proposed system is based on the fast adsorption/desorption behavior of water originated from human breath into the sensor films deposited on the QCM electrode.

Respiratory Monitoring by Porphyrin Modified Quartz Crystal Microbalance Sensors

PubMed Central

Selyanchyn, Roman; Korposh, Serhiy; Wakamatsu, Shunichi; Lee, Seung-Woo

2011-01-01

A respiratory monitoring system based on a quartz crystal microbalance (QCM) sensor with a functional film was designed and investigated. Porphyrins 5,10,15,20-tetrakis-(4-sulfophenyl)-21H,23H-porphine (TSPP) and 5,10,15,20-tetrakis-(4-sulfophenyl)-21H, 23H-porphine manganese (III) chloride (MnTSPP) used as sensitive elements were assembled with a poly(diallyldimethyl ammonium chloride) (PDDA). Films were deposited on the QCM resonators using layer-by-layer method in order to develop the sensor. The developed system, in which the sensor response reflects lung movements, was able to track human respiration providing respiratory rate (RR) and respiratory pattern (RP). The sensor system was tested on healthy volunteers to compare RPs and calculate RRs. The operation principle of the proposed system is based on the fast adsorption/desorption behavior of water originated from human breath into the sensor films deposited on the QCM electrode. PMID:22346621

[Comparative study of respiratory exchanging surfaces in birds and mammals].

PubMed

Jammes, Y

1975-01-01

Anatomical studies of the respiratory apparatus of birds show evidences for a gas exchanging tubular system (parabronchi and air capillaries); these exchanging structures are entirely dissociated from the ventilatory drive acting on the air sacs. A "cross-current" gas exchanging system (perpendicular disposition of air and blood capillaries) allow a good wash-out of carbon dioxide (PaCO2 lower than PECO2). The great efficiency of this lung is allowed by its very large diffusive surface (ASa) and by the high values of lung specific oxygen diffusing capacity (DO2/ASa) and of O2 extraction coefficient in inspired air. The ventilatory pattern of birds is characterized by a greater tidal volume and a smaller respiratory frequency than in mammals of same weight. Respiratory centers of birds receive afferences from lung stretch receptors, CO2-sensitive lung receptors and arterial chemoreceptors.

Respiratory impedance is correlated with airway narrowing in asthma using three-dimensional computed tomography.

PubMed

Karayama, M; Inui, N; Mori, K; Kono, M; Hozumi, H; Suzuki, Y; Furuhashi, K; Hashimoto, D; Enomoto, N; Fujisawa, T; Nakamura, Y; Watanabe, H; Suda, T

2018-03-01

Respiratory impedance comprises the resistance and reactance of the respiratory system and can provide detailed information on respiratory function. However, details of the relationship between impedance and morphological airway changes in asthma are unknown. We aimed to evaluate the correlation between imaging-based airway changes and respiratory impedance in patients with asthma. Respiratory impedance and spirometric data were evaluated in 72 patients with asthma and 29 reference subjects. We measured the intraluminal area (Ai) and wall thickness (WT) of third- to sixth-generation bronchi using three-dimensional computed tomographic analyses, and values were adjusted by body surface area (BSA, Ai/BSA, and WT/the square root (√) of BSA). Asthma patients had significantly increased respiratory impedance, decreased Ai/BSA, and increased WT/√BSA, as was the case in those without airflow limitation as assessed by spirometry. Ai/BSA was inversely correlated with respiratory resistance at 5 Hz (R5) and 20 Hz (R20). R20 had a stronger correlation with Ai/BSA than did R5. Ai/BSA was positively correlated with forced expiratory volume in 1 second/forced vital capacity ratio, percentage predicted forced expiratory volume in 1 second, and percentage predicted mid-expiratory flow. WT/√BSA had no significant correlation with spirometry or respiratory impedance. Respiratory resistance is associated with airway narrowing. © 2018 John Wiley & Sons Ltd.

Micro-gas analysis system for measurement of nitric oxide and nitrogen dioxide: respiratory treatment and environmental mobile monitoring.

PubMed

Toda, Kei; Hato, Yuki; Ohira, Shin-ichi; Namihira, Takao

2007-11-05

In this paper, novel microsystems for gas analysis and gas generation are described. The same microchannel devices covered with a gas permeable membrane were used for both the gas collection and the gas generation. For the first time, a dual liquid flow system was utilized in a micro-gas analysis system. Even though micropumps are utilized in the dual line microsystem, a good baseline was obtained in the NO2 measurement with Griess-Saltzman chemistry. The system was developed for on-site measurements in medical treatment; the treatment is of respiratory disease syndrome by NO inhalation and the monitoring is of the product NO and the harmful byproduct NO2. The system was also applied to mobile atmospheric monitoring. Chemical NO generation using the microchannel device was investigated for safe NO inhalation as an alternative to a NO generator based on pulsed arc discharge.

Extraction and Analysis of Respiratory Motion Using Wearable Inertial Sensor System during Trunk Motion

PubMed Central

Gaidhani, Apoorva; Moon, Kee S.; Ozturk, Yusuf; Lee, Sung Q.; Youm, Woosub

2017-01-01

Respiratory activity is an essential vital sign of life that can indicate changes in typical breathing patterns and irregular body functions such as asthma and panic attacks. Many times, there is a need to monitor breathing activity while performing day-to-day functions such as standing, bending, trunk stretching or during yoga exercises. A single IMU (inertial measurement unit) can be used in measuring respiratory motion; however, breathing motion data may be influenced by a body trunk movement that occurs while recording respiratory activity. This research employs a pair of wireless, wearable IMU sensors custom-made by the Department of Electrical Engineering at San Diego State University. After appropriate sensor placement for data collection, this research applies principles of robotics, using the Denavit-Hartenberg convention, to extract relative angular motion between the two sensors. One of the obtained relative joint angles in the “Sagittal” plane predominantly yields respiratory activity. An improvised version of the proposed method and wearable, wireless sensors can be suitable to extract respiratory information while performing sports or exercises, as they do not restrict body motion or the choice of location to gather data. PMID:29258214

Nonuniform spatial patterns of respiratory activity within biofilms during disinfection.

PubMed Central

Huang, C T; Yu, F P; McFeters, G A; Stewart, P S

1995-01-01

Fluorescent stains in conjunction with cryoembedding and image analysis were applied to demonstrate spatial gradients in respiratory activity within bacterial biofilms during disinfection with monochloramine. Biofilms of Klebsiella pneumoniae and Pseudomonas aeruginosa grown together on stainless steel surfaces in continuous-flow annular reactors were treated with 2 mg of monochloramine per liter (influent concentration) for 2 h. Relatively little biofilm removal occurred as evidenced by total cell direct counts. Plate counts (of both species summed) indicated an average 1.3-log decrease after exposure to 2 mg of monochloramine per liter. The fluorogenic redox indicator 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and the DNA stain 4',6-diamidino-2-phenylindole (DAPI) were used to differentiate respiring and nonrespiring cells in biofilms. Epifluorescence micrographs of frozen biofilm cross sections clearly revealed gradients of respiratory activity within biofilms in response to monochloramine treatment. These gradients in specific respiratory activity were quantified by calculating the ratio of CTC and DAPI intensities measured by image analysis. Cells near the biofilm-bulk fluid interface lost respiratory activity first. After 2 h of biocide treatment, greater respiratory activity persisted deep in the biofilm than near the biofilm-bulk fluid interface. PMID:7793945

[Alkalosis].

PubMed

Kościelska, Malgorzata; Mieczkowski, Mariusz

2013-01-01

An elevation of arterial blood pH called alkalosis remains an underestimated condition in hospitalized patients. Serious alkalosis can be associated with high risk of death. The disorder can be caused by increased concentration of bicarbonate (metabolic alkalosis) or decreased concentration of carbon dioxide (respiratory alkalosis). In most cases of metabolic alkalosis it is generated by vomiting or diuretic use, whereas respiratory alkalosis is provoked by hyperventilation associated with respiratory or neurological disorder. Maintenance of metabolic alkalosis is possible only in patients with impaired renal base excretion which is most often produced by hypochloremia. In both respiratory and metabolic alkaloses treatment depends on the underlying factor. In hyperventilation syndrome is based on behavioral therapy. In most cases of metabolic alkalosis the administration of sodium and potassium chloride forms a substantial part of therapy.

[Microbiological diagnosis of viral respiratory infections].

PubMed

Eiros, José M; Ortiz de Lejarazu, Raúl; Tenorio, Alberto; Casas, Inmaculada; Pozo, Francisco; Ruiz, Guillermo; Pérez-Breña, Pilar

2009-03-01

Acute respiratory infection is the most common disease occurring over a person's lifetime, with etiological variations determined mainly by age, environmental circumstances, the healthcare setting, and the underlying pathology. More than 200 different viruses distributed in six viral families have been implicated in the pathogenesis of respiratory tract infection. These facts are generating an increasing diagnostic demand that should be incorporated into the healthcare setting without delay. To meet this demand, the Spanish Society of Infectious Diseases and Clinical Microbiology has updated its Standard Procedure for the microbiological diagnosis of viral respiratory infection. This document contains an update primarily of infections caused by influenza viruses, and secondarily, infections due to other conventional and emerging respiratory viruses. In all cases, the methods for direct virological diagnosis (cell culture, and detection of antigens and nucleic acid) are reviewed, with special reference to techniques for molecular detection and genetic characterization.

A Technique for Generating Volumetric Cine-Magnetic Resonance Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Wendy; Ren, Lei, E-mail: lei.ren@duke.edu; Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina

Purpose: The purpose of this study was to develop a techique to generate on-board volumetric cine-magnetic resonance imaging (VC-MRI) using patient prior images, motion modeling, and on-board 2-dimensional cine MRI. Methods and Materials: One phase of a 4-dimensional MRI acquired during patient simulation is used as patient prior images. Three major respiratory deformation patterns of the patient are extracted from 4-dimensional MRI based on principal-component analysis. The on-board VC-MRI at any instant is considered as a deformation of the prior MRI. The deformation field is represented as a linear combination of the 3 major deformation patterns. The coefficients of themore » deformation patterns are solved by the data fidelity constraint using the acquired on-board single 2-dimensional cine MRI. The method was evaluated using both digital extended-cardiac torso (XCAT) simulation of lung cancer patients and MRI data from 4 real liver cancer patients. The accuracy of the estimated VC-MRI was quantitatively evaluated using volume-percent-difference (VPD), center-of-mass-shift (COMS), and target tracking errors. Effects of acquisition orientation, region-of-interest (ROI) selection, patient breathing pattern change, and noise on the estimation accuracy were also evaluated. Results: Image subtraction of ground-truth with estimated on-board VC-MRI shows fewer differences than image subtraction of ground-truth with prior image. Agreement between normalized profiles in the estimated and ground-truth VC-MRI was achieved with less than 6% error for both XCAT and patient data. Among all XCAT scenarios, the VPD between ground-truth and estimated lesion volumes was, on average, 8.43 ± 1.52% and the COMS was, on average, 0.93 ± 0.58 mm across all time steps for estimation based on the ROI region in the sagittal cine images. Matching to ROI in the sagittal view achieved better accuracy when there was substantial breathing pattern change. The technique was robust against noise levels up to SNR = 20. For patient data, average tracking errors were less than 2 mm in all directions for all patients. Conclusions: Preliminary studies demonstrated the feasibility of generating real-time VC-MRI for on-board localization of moving targets in radiation therapy.« less

The deepwater horizon oil spill coast guard cohort study: A cross-sectional study of acute respiratory health symptoms.

PubMed

Alexander, Melannie; Engel, Lawrence S; Olaiya, Nathan; Wang, Li; Barrett, John; Weems, Laura; Schwartz, Erica G; Rusiecki, Jennifer A

2018-04-01

Over 8500 United States Coast Guard (USCG) personnel were deployed in response to the Deepwater Horizon (DWH) oil spill; however, human respiratory effects as a result of spill-related exposures are relatively unknown. USCG personnel who responded to the DWH oil spill were queried via survey on exposures to crude oil and oil dispersant, and acute respiratory symptoms experienced during deployment. Adjusted log binomial regressions were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CI), investigating the associations between oil spill exposures and respiratory symptoms. 4855 USCG personnel completed the survey. More than half (54.6%) and almost one-fourth (22.0%) of responders were exposed to crude oil and oil dispersants, respectively. Coughing was the most prevalent symptom (19.4%), followed by shortness of breath (5.5%), and wheezing (3.6%). Adjusted analyses showed an exposure-response relationship between increasing deployment duration and likelihood of coughing, shortness of breath, and wheezing in the pre-capping period. A similar pattern was observed in the post-capping period for coughing and wheezing. Adjusted analyses revealed increased PRs for coughing (PR=1.92), shortness of breath (PR=2.60), and wheezing (PR=2.68) for any oil exposure. Increasing frequency of inhalation of oil was associated with increased likelihood of all three respiratory symptoms. A similar pattern was observed for contact with oil dispersants for coughing and shortness of breath. The combination of both oil and oil dispersants presented associations that were much greater in magnitude than oil alone for coughing (PR=2.72), shortness of breath (PR=4.65), and wheezing (PR=5.06). Results from the present study suggested strong relationships between oil and oil dispersant exposures and acute respiratory symptoms among disaster responders. Future prospective studies will be needed to confirm these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiological denoising of BOLD fMRI data using Regressor Interpolation at Progressive Time Delays (RIPTiDe) processing of concurrent fMRI and near-infrared spectroscopy (NIRS).

PubMed

Frederick, Blaise deB; Nickerson, Lisa D; Tong, Yunjie

2012-04-15

Confounding noise in BOLD fMRI data arises primarily from fluctuations in blood flow and oxygenation due to cardiac and respiratory effects, spontaneous low frequency oscillations (LFO) in arterial pressure, and non-task related neural activity. Cardiac noise is particularly problematic, as the low sampling frequency of BOLD fMRI ensures that these effects are aliased in recorded data. Various methods have been proposed to estimate the noise signal through measurement and transformation of the cardiac and respiratory waveforms (e.g. RETROICOR and respiration volume per time (RVT)) and model-free estimation of noise variance through examination of spatial and temporal patterns. We have previously demonstrated that by applying a voxel-specific time delay to concurrently acquired near infrared spectroscopy (NIRS) data, we can generate regressors that reflect systemic blood flow and oxygenation fluctuations effects. Here, we apply this method to the task of removing physiological noise from BOLD data. We compare the efficacy of noise removal using various sets of noise regressors generated from NIRS data, and also compare the noise removal to RETROICOR+RVT. We compare the results of resting state analyses using the original and noise filtered data, and we evaluate the bias for the different noise filtration methods by computing null distributions from the resting data and comparing them with the expected theoretical distributions. Using the best set of processing choices, six NIRS-generated regressors with voxel-specific time delays explain a median of 10.5% of the variance throughout the brain, with the highest reductions being seen in gray matter. By comparison, the nine RETROICOR+RVT regressors together explain a median of 6.8% of the variance in the BOLD data. Detection of resting state networks was enhanced with NIRS denoising, and there were no appreciable differences in the bias of the different techniques. Physiological noise regressors generated using Regressor Interpolation at Progressive Time Delays (RIPTiDe) offer an effective method for efficiently removing hemodynamic noise from BOLD data. Copyright © 2012 Elsevier Inc. All rights reserved.

Respiration in Aquatic Insects.

ERIC Educational Resources Information Center

MacFarland, John

1985-01-01

This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

Millivolt-scale DC shifts in the human scalp EEG: evidence for a nonneuronal generator.

PubMed

Voipio, Juha; Tallgren, Pekka; Heinonen, Erkki; Vanhatalo, Sampsa; Kaila, Kai

2003-04-01

Slow shifts in the human scalp-recorded EEG, including those related to changes in brain CO(2) levels, have been generally assumed to result from changes in the level of tonic excitation of apical dendrites of cortical pyramidal neurons. We readdressed this issue using DC-EEG shifts elicited in healthy adult subjects by hypo- or hypercapnia. A 3-min period of hyperventilation resulted in a prompt negative shift with a rate of up to 10 microV/s at the vertex (Cz) and an extremely steep dependence (up to 100 microV/mmHg) on the end-tidal Pco(2). This shift had a maximum of up to -2 mV at Cz versus the temporal derivations (T3/T4). Hyperventilation-like breathing of 5% CO(2)-95% O(2), which does not lead to a significant hypocapnia, resulted in a near-complete block of the negative DC shift at Cz. Hypoventilation, or breathing 5% CO(2) in air at normal respiratory rate, induced a positive shift. The high amplitude of the voltage gradients on the scalp induced by hyperventilation is not consistent with a neuronal origin. Instead, the present data suggest that they are generated by extracortical volume currents driven by a Pco(2)-dependent potential difference across epithelia separating the cerebrospinal fluid and blood. Since changes in respiratory patterns and, hence, in the level of brain Pco(2), are likely to occur under a number of experimental conditions in which slow EEG responses have been reported (e.g., attention shifts, preparatory states, epileptic seizures, and hypoxic episodes), the present results call for a thorough reexamination of the mechanisms underlying scalp-recorded DC-EEG responses.

Droplets and modes of respiratory disease transmission

NASA Astrophysics Data System (ADS)

Bourouiba, Lydia

2014-11-01

Direct observation of violent expirations such as sneezes and coughs events reveal that such flows are multiphase turbulent buoyant clouds with suspended droplets of various sizes. The effects of ambient conditions indoors, such as moisture and temperature, coupled with the water content of such clouds are key in shaping the pathogen footprint emitted by potentially sick individuals. Such pathogen footprint can change the patterns of respiratory disease transmission. We discuss how the fluid dynamics of violent expirations can help inform how.

Physiological effects and optimisation of nasal assist-control ventilation for patients with chronic obstructive pulmonary disease in respiratory failure

PubMed Central

Girault, C.; Chevron, V.; Richard, J. C.; Daudenthun, I.; Pasquis, P.; Leroy, J.; Bonmarchand, G.

1997-01-01

BACKGROUND: A study was undertaken to investigate the effects of non- invasive assist-control ventilation (ACV) by nasal mask on respiratory physiological parameters and comfort in acute on chronic respiratory failure (ACRF). METHODS: Fifteen patients with chronic obstructive pulmonary disease (COPD) were prospectively and randomly assigned to two non-invasive ventilation (NIV) sequences in spontaneous breathing (SB) and ACV mode. ACV settings were always optimised and therefore subsequently adjusted according to patient's tolerance and air leaks. RESULTS: ACV significantly decreased all the total inspiratory work of breathing (WOBinsp) parameters, pressure time product, and oesophageal pressure variation in comparison with SB mode. The ACV mode also resulted in a significant reduction in surface diaphragmatic electromyographic activity to 36% of the control values and significantly improved the breathing pattern. SB did not change the arterial blood gas tensions from baseline values whereas ACV significantly improved both the PaO2 from a mean (SD) of 8.45 (2.95) kPa to 13.31 (2.15) kPa, PaCO2 from 9.52 (1.61) kPa to 7.39 (1.39) kPa, and the pH from 7.32 (0.03) to 7.40 (0.07). The respiratory comfort was significantly lower with ACV than with SB. CONCLUSIONS: This study shows that the clinical benefit of non-invasive ACV in the management of ACRF in patients with COPD results in a reduced inspiratory muscle activity providing an improvement in breathing pattern and gas exchange. Despite respiratory discomfort, the muscle rest provided appears sufficient when ACV settings are optimised. 


 PMID:9337827

Atypical patterns of respiratory sinus arrhythmia index an endophenotype for depression

PubMed Central

Yaroslavsky, Ilya; Rottenberg, Jonathan; Kovacs, Maria

2015-01-01

Can atypical patterns of parasympathetic nervous system activity serve as endophenotypes for depression? Using respiratory sinus arrhythmia (RSA) as an index of parasympathetic nervous system function, we examined this question in two studies: one involving mothers with and without depression histories and their offspring (at high and low risk for depression, respectively), and a further study of adolescent sibling pairs concordant and discordant for major depression. In both studies, subjects were exposed to sad mood induction; subjects’ RSA was monitored during rest periods and in response to the mood induction. We used Gottesman and Gould’s (2003) criteria for an endophenotype and a priori defined “atypical” and “normative” RSA patterns (combinations of resting RSA and RSA reactivity). We found that atypical RSA patterns (a) predicted current depressive episodes and remission status among women with histories of juvenile onset depression and healthy controls, (b) predicted longitudinal trajectories of depressive symptoms among high- and low-risk young offspring, (c) were concordant across mothers and their juvenile offspring, (d) were more prevalent among never-depressed youth at high risk for depression than their low-risk peers, and (e) were more concordant across adolescent sibling pairs in which both versus only one had a history of major depression. Thus, the results support atypical RSA patterns as an endophenotype for depression. Possible mechanisms by which RSA patterns increase depression risk and their genetic contributors are discussed. PMID:25422965

Feature-based respiratory motion tracking in native fluoroscopic sequences for dynamic roadmaps during minimally invasive procedures in the thorax and abdomen

NASA Astrophysics Data System (ADS)

Wagner, Martin G.; Laeseke, Paul F.; Schubert, Tilman; Slagowski, Jordan M.; Speidel, Michael A.; Mistretta, Charles A.

2017-03-01

Fluoroscopic image guidance for minimally invasive procedures in the thorax and abdomen suffers from respiratory and cardiac motion, which can cause severe subtraction artifacts and inaccurate image guidance. This work proposes novel techniques for respiratory motion tracking in native fluoroscopic images as well as a model based estimation of vessel deformation. This would allow compensation for respiratory motion during the procedure and therefore simplify the workflow for minimally invasive procedures such as liver embolization. The method first establishes dynamic motion models for both the contrast-enhanced vasculature and curvilinear background features based on a native (non-contrast) and a contrast-enhanced image sequence acquired prior to device manipulation, under free breathing conditions. The model of vascular motion is generated by applying the diffeomorphic demons algorithm to an automatic segmentation of the subtraction sequence. The model of curvilinear background features is based on feature tracking in the native sequence. The two models establish the relationship between the respiratory state, which is inferred from curvilinear background features, and the vascular morphology during that same respiratory state. During subsequent fluoroscopy, curvilinear feature detection is applied to determine the appropriate vessel mask to display. The result is a dynamic motioncompensated vessel mask superimposed on the fluoroscopic image. Quantitative evaluation of the proposed methods was performed using a digital 4D CT-phantom (XCAT), which provides realistic human anatomy including sophisticated respiratory and cardiac motion models. Four groups of datasets were generated, where different parameters (cycle length, maximum diaphragm motion and maximum chest expansion) were modified within each image sequence. Each group contains 4 datasets consisting of the initial native and contrast enhanced sequences as well as a sequence, where the respiratory motion is tracked. The respiratory motion tracking error was between 1.00 % and 1.09 %. The estimated dynamic vessel masks yielded a Sørensen-Dice coefficient between 0.94 and 0.96. Finally, the accuracy of the vessel contours was measured in terms of the 99th percentile of the error, which ranged between 0.64 and 0.96 mm. The presented results show that the approach is feasible for respiratory motion tracking and compensation and could therefore considerably improve the workflow of minimally invasive procedures in the thorax and abdomen

Swallowing function and chronic respiratory diseases: Systematic review.

PubMed

Ghannouchi, Ines; Speyer, Renée; Doma, Kenji; Cordier, Reinie; Verin, Eric

2016-08-01

The precise coordination between breathing and swallowing is an important mechanism to prevent pulmonary aspiration. Factors that alter breathing patterns and ventilation, such as chronic respiratory diseases, may influence that precise coordination of breathing and swallowing. The purpose of this systematic literature review is to examine the effects of chronic respiratory diseases on swallowing function. Literature searches were performed using the electronic databases PubMed and Embase. All articles meeting the eligibility criteria up to March 2016 were included. All articles included studied Chronic Obstructive Pulmonary Diseases (COPD) or Obstructive Sleep Apnea (OSA); no studies involving other respiratory diseases were found. A total of 1069 abstracts were retrieved, of which twenty-six studies met the inclusion criteria; eleven studies dealt with OSA and fifteen studies dealt with COPD. The outcome data indicate that chronic respiratory diseases increase the prevalence of oropharyngeal dysphagia (OD) in patients. However, the relative small number of studies, differences in selection criteria, definitions and assessment techniques used for diagnosing OSA, COPD, and OD point to the need for further research. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Improved Dynamic Model for the Respiratory Response to Exercise

PubMed Central

Serna, Leidy Y.; Mañanas, Miguel A.; Hernández, Alher M.; Rabinovich, Roberto A.

2018-01-01

Respiratory system modeling has been extensively studied in steady-state conditions to simulate sleep disorders, to predict its behavior under ventilatory diseases or stimuli and to simulate its interaction with mechanical ventilation. Nevertheless, the studies focused on the instantaneous response are limited, which restricts its application in clinical practice. The aim of this study is double: firstly, to analyze both dynamic and static responses of two known respiratory models under exercise stimuli by using an incremental exercise stimulus sequence (to analyze the model responses when step inputs are applied) and experimental data (to assess prediction capability of each model). Secondly, to propose changes in the models' structures to improve their transient and stationary responses. The versatility of the resulting model vs. the other two is shown according to the ability to simulate ventilatory stimuli, like exercise, with a proper regulation of the arterial blood gases, suitable constant times and a better adjustment to experimental data. The proposed model adjusts the breathing pattern every respiratory cycle using an optimization criterion based on minimization of work of breathing through regulation of respiratory frequency. PMID:29467674

Self-Generated Analogical Models of Respiratory Pathways

ERIC Educational Resources Information Center

Lee, Yeung Chung

2015-01-01

Self-generated analogical models have emerged recently as alternatives to teacher-supplied analogies and seem to have good potential to promote deep learning and scientific thinking. However, studies of the ways and contexts in which students generate these models are still too limited to allow a fuller appraisal of these models' effectiveness in…

Short-term population-based and spatiotemporal nonlinear concentration-response associations between fine particulate matter and children's respiratory clinic visits

NASA Astrophysics Data System (ADS)

Yu, Hwa-Lung; Chien, Lung-Chang

2014-05-01

Advert health impacts associated with the PM2.5 exposure have been confirmed in mortality and cardiovascular diseases; however, findings of the influence of PM2.5 on respiratory diseases investigated among previous studies are still inconsistent. We investigated the short-term population-based associations between the respiratory clinic visits of children population and the PM2.5 exposure levels with considering both the spatiotemporal distributions of the ambient pollution and clinic visit data. We applied a spatiotemporal structured additive regression model to examine the concentration-response (C-R) association between daily children's respiratory clinic visits and PM2.5 concentrations. The analysis was performed separately on the four selected respiratory disease categories of the population-based dataset, obtained from Taiwan National Health Insurance database, covering the 41 districts in Taipei area during the period of 2005 to 2007. This study reveals a strong nonlinear C-R pattern that the PM2.5 increment can significantly affect respiratory health at PM2.5 concentration ≤ 18.17µg/m3 for both preschool children and schoolchildren. The elevated risks are especially present in the category of acute respiratory infections. PM2.5 increase is mostly non-significant to the more severe respiratory diseases, e.g., COPD and pneumonia, over the ranges of 8.85-92.45µg/m3. The significantly higher relative rate of respiratory clinic visit most likely concentrated at populated areas. We highlight the nonlinearity of the respiratory health impacts of PM2.5 on children's populations from the first study, to our knowledge, to investigate this population-based association. The strong nonlinearity can possibly cause the inconsistency of PM2.5 health impact assessments with linear assumptions.

SU-F-I-15: Evaluation of a New MR-Compatible Respiratory Motion Device at 3T

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soliman, A; Sunnybrook Health Sciences Centre, Toronto, ON; Chugh, B

Purpose: Recent advances in MRI-guided radiotherapy has inspired the development of MRI-compatible motion devices that simulate patient periodic motion in the scanner, particularly respiratory motion. Most commercial devices rely on non MR-safe ferromagnetic stepper motors which are not practical for regular QA testing. This work evaluates the motion performance of a new fully MRI compatible respiratory motion device at 3T. Methods: The QUASAR™ MRI-compatible respiratory motion phantom has been recently developed by Modus QA Inc., London, ON, Canada. The prototype is constructed from diamagnetic materials with linear motion generated using MRI-compatible piezoelectric motors that can be safely inserted in themore » scanner bore. The tumor was represented by a fillable sphere and is attached to the linear motion generator. The spherical tumor-representative and its surroundings were filled with different concentrations of MnCl2 to produce realistic relaxation times. The motion was generated along the longitudinal (H/F) axis of the bore using sinusoidal reference waveform (amplitude = 15 mm, frequency 0.25 Hz). Imaging was then performed on 3T Philips Achieva using a 32-channel cardiac coil. Fast 2D spoiled gradient-echo was used with a spatial resolution of 1.8 × 1.8 mm{sup 2} and slice thickness of 4 mm. The motion waveform was then measured on the resultant image series by tracking the centroid of the sphere through the time series. This image-derived measured motion was compared to the software-generated reference waveform. Results: No visible distortions from the device were observed on the images. Excellent agreement between the measured and the reference waveforms were obtained. Negligible motion was observed in the lateral (R/L) direction. Conclusion: Our investigation demonstrates that this piezo-electric motor design is effective at simulating periodic motion and is a potential candidate for MRI-radiotherapy respiratory motion simulation. Future work should focus on evaluating non-sinusoidal waveforms, fast 3D pulse sequences, and perform dosimetric QA.« less

Recent advances in delivery mechanisms for aerosol therapy during pediatric respiratory diseases.

PubMed

Wu, Yue'E; Zhang, Chonglin; Zhen, Qing

2018-04-01

The treatment of pediatric surgery diseases via utilization of aerosol delivery mechanisms is in progress for the betterment of pediatric care. Over the years, aerosol therapy has come to play an integral role in the treatment of pediatric respiratory diseases. Inhaled aerosol agents such as bronchodilators, corticosteroids, antibiotics, and mucolytics are commonly delivered to spontaneously breathing pediatric patients with a tracheostomy. Administering therapeutic inhaled aerosols to pediatric patients is challenging. The pediatric population ranges in age, which means patients with different airway sizes, breathing patterns, and cooperation levels. These patient-related factors impact the deposition of aerosol drugs in the lungs. The present review article will discuss the recent advancements in the delivery mechanisms for aerosol therapy in pediatric patients with respiratory diseases.

[Temperature sensitivity and the indicators of respiration in humans in the normal state and during local cooling].

PubMed

Kozyreva, T V; Simonova, T G

1991-01-01

The examination has shown that people who have many cold spots on the forearm possess high ventilation volume and breathing frequency and low value of oxygen utilization. These facts can evidence for the effect of cold skin receptors on the respiratory patterns. The skin temperature, at which the maximal cooling-induced changes of respiratory parameters are observed depends on the dynamic activity of cold skin thermoreceptors: the greater number of cold spots in the hand and forearm, the lesser cooling is necessary to cause the maximal increase of oxygen consumption and change of respiratory volume. The latter increased in the case of hand cooling and decreased in the case of the forearm cooling.

Chest Wall Motion during Speech Production in Patients with Advanced Ankylosing Spondylitis

ERIC Educational Resources Information Center

Kalliakosta, Georgia; Mandros, Charalampos; Tzelepis, George E.

2007-01-01

Purpose: To test the hypothesis that ankylosing spondylitis (AS) alters the pattern of chest wall motion during speech production. Method: The pattern of chest wall motion during speech was measured with respiratory inductive plethysmography in 6 participants with advanced AS (5 men, 1 woman, age 45 plus or minus 8 years, Schober test 1.45 plus or…

Effect of Sarizotan, a 5-HT1a and D2-like receptor agonist, on respiration in three mouse models of Rett syndrome.

PubMed

Abdala, Ana P; Lioy, Daniel T; Garg, Saurabh K; Knopp, Sharon J; Paton, Julian F R; Bissonnette, John M

2014-06-01

Disturbances in respiration are common and debilitating features of Rett syndrome (RTT). A previous study showed that the 5-HT1a receptor agonist (R)-(+)-8-hydroxy-dipropyl-2-aminotetralin hydrobromide (8-OH-DPAT) significantly reduced the incidence of apnea and the irregular breathing pattern in a mouse model of the disorder. 8-OH-DPAT, however, is not available for clinical practice. Sarizotan, a full 5-HT1a agonist and a dopamine D2-like agonist/partial agonist, has been used in clinical trials for the treatment of l-dopa-induced dyskinesia. The purpose of this study was to evaluate the effects of sarizotan on respiration and locomotion in mouse models of RTT. Studies were performed in Bird and Jaenisch strains of methyl-CpG-binding protein 2--deficient heterozygous female and Jaenisch strain Mecp2 null male mice and in knock-in heterozygous female mice of a common nonsense mutation (R168X). Respiratory pattern was determined with body plethysmography, and locomotion was determined with open-field recording. Sarizotan or vehicle was administered 20 minutes before a 30-minute recording of respiratory pattern or motor behavior. In separate studies, a crossover design was used to administer the drug for 7 and for 14 days. Sarizotan reduced the incidence of apnea in all three RTT mouse models to approximately 15% of their pretreatment levels. The irregular breathing pattern was corrected to that of wild-type littermates. When administered for 7 or 14 days, apnea decreased to 25 to 33% of the incidence seen with vehicle. This study indicates that the clinically approved drug sarizotan is an effective treatment for respiratory disorders in mouse models of RTT.

Effect of Sarizotan, a 5-HT1a and D2-Like Receptor Agonist, on Respiration in Three Mouse Models of Rett Syndrome

PubMed Central

Abdala, Ana P.; Lioy, Daniel T.; Garg, Saurabh K.; Knopp, Sharon J.; Paton, Julian F. R.

2014-01-01

Disturbances in respiration are common and debilitating features of Rett syndrome (RTT). A previous study showed that the 5-HT1a receptor agonist (R)-(+)-8-hydroxy-dipropyl-2-aminotetralin hydrobromide (8-OH-DPAT) significantly reduced the incidence of apnea and the irregular breathing pattern in a mouse model of the disorder. 8-OH-DPAT, however, is not available for clinical practice. Sarizotan, a full 5-HT1a agonist and a dopamine D2–like agonist/partial agonist, has been used in clinical trials for the treatment of l-dopa–induced dyskinesia. The purpose of this study was to evaluate the effects of sarizotan on respiration and locomotion in mouse models of RTT. Studies were performed in Bird and Jaenisch strains of methyl-CpG–binding protein 2-–deficient heterozygous female and Jaenisch strain Mecp2 null male mice and in knock-in heterozygous female mice of a common nonsense mutation (R168X). Respiratory pattern was determined with body plethysmography, and locomotion was determined with open-field recording. Sarizotan or vehicle was administered 20 minutes before a 30-minute recording of respiratory pattern or motor behavior. In separate studies, a crossover design was used to administer the drug for 7 and for 14 days. Sarizotan reduced the incidence of apnea in all three RTT mouse models to approximately 15% of their pretreatment levels. The irregular breathing pattern was corrected to that of wild-type littermates. When administered for 7 or 14 days, apnea decreased to 25 to 33% of the incidence seen with vehicle. This study indicates that the clinically approved drug sarizotan is an effective treatment for respiratory disorders in mouse models of RTT. PMID:24351104

Real-time continuous visual biofeedback in the treatment of speech breathing disorders following childhood traumatic brain injury: report of one case.

PubMed

Murdoch, B E; Pitt, G; Theodoros, D G; Ward, E C

1999-01-01

The efficacy of traditional and physiological biofeedback methods for modifying abnormal speech breathing patterns was investigated in a child with persistent dysarthria following severe traumatic brain injury (TBI). An A-B-A-B single-subject experimental research design was utilized to provide the subject with two exclusive periods of therapy for speech breathing, based on traditional therapy techniques and physiological biofeedback methods, respectively. Traditional therapy techniques included establishing optimal posture for speech breathing, explanation of the movement of the respiratory muscles, and a hierarchy of non-speech and speech tasks focusing on establishing an appropriate level of sub-glottal air pressure, and improving the subject's control of inhalation and exhalation. The biofeedback phase of therapy utilized variable inductance plethysmography (or Respitrace) to provide real-time, continuous visual biofeedback of ribcage circumference during breathing. As in traditional therapy, a hierarchy of non-speech and speech tasks were devised to improve the subject's control of his respiratory pattern. Throughout the project, the subject's respiratory support for speech was assessed both instrumentally and perceptually. Instrumental assessment included kinematic and spirometric measures, and perceptual assessment included the Frenchay Dysarthria Assessment, Assessment of Intelligibility of Dysarthric Speech, and analysis of a speech sample. The results of the study demonstrated that real-time continuous visual biofeedback techniques for modifying speech breathing patterns were not only effective, but superior to the traditional therapy techniques for modifying abnormal speech breathing patterns in a child with persistent dysarthria following severe TBI. These results show that physiological biofeedback techniques are potentially useful clinical tools for the remediation of speech breathing impairment in the paediatric dysarthric population.

Effect of feeding pattern on infant illness in Chinese cities.

PubMed

Cai, Li; Yu, Pan; Zhang, Yumei; Yang, Xiaoguang; Li, Wenjun; Wang, Peiyu

2016-05-01

To investigate the effect of different feeding patterns on the occurrence of diseases among infants. Data on socio-economic status, feeding patterns before 6 months (exclusive breast-feeding (EBF); mixed feeding with breast milk and formula (MBF); exclusive formula-feeding (EFF)) and illness of infants were collected via face-to-face interviews. The proportions of infants who had ever been ill or hospitalized and their potential influence factors were investigated. Eight large cities in China. Infants (n 1654) aged 0-11·9 months were recruited from hospitals. For infants aged 0-2·9 months, the percentage who had been ill was 19·2%, 24·1% and 26·3% among the EBF, MBF and EFF groups, respectively. For those aged 3-5·9 and 6-11·9 months, the corresponding percentages were 41·6%, 45·6% and 51·0%, and 67·0%, 73·4% and 67·7%. Respiratory disease was the most common reported illness and cause of hospitalization. The risks of having (total) illness, diarrhoea and respiratory disease increased significantly with age, but not allergic disease. Compared with EBF, MBF and EFF infants had significantly higher risks of having illnesses except for allergic disease, and feeding patterns were not related to hospitalization. Low birth weight, middle family income and low level of mother's education also increased the risk of illness. A protective effect of EBF against total illness in urban Chinese infants was found. An increasing trend with age was observed among the percentages of infants who had been ill or had diarrhoea or respiratory disease, but not allergic disease.

Disclosing respiratory co-infections: a broad-range panel assay for avian respiratory pathogens on a nanofluidic PCR platform.

PubMed

Croville, Guillaume; Foret, Charlotte; Heuillard, Pauline; Senet, Alexis; Delpont, Mattias; Mouahid, Mohammed; Ducatez, Mariette F; Kichou, Faouzi; Guerin, Jean-Luc

2018-06-01

Respiratory syndromes (RS) are among the most significant pathological conditions in edible birds and are caused by complex coactions of pathogens and environmental factors. In poultry, low pathogenic avian influenza A viruses, metapneumoviruses, infectious bronchitis virus, infectious laryngotracheitis virus, Mycoplasma spp. Escherichia coli and/or Ornithobacterium rhinotracheale in turkeys are considered as key co-infectious agents of RS. Aspergillus sp., Pasteurella multocida, Avibacterium paragallinarum or Chlamydia psittaci may also be involved in respiratory outbreaks. An innovative quantitative PCR method, based on a nanofluidic technology, has the ability to screen up to 96 samples with 96 pathogen-specific PCR primers, at the same time, in one run of real-time quantitative PCR. This platform was used for the screening of avian respiratory pathogens: 15 respiratory agents, including viruses, bacteria and fungi potentially associated with respiratory infections of poultry, were targeted. Primers were designed and validated for SYBR green real-time quantitative PCR and subsequently validated on the Biomark high throughput PCR nanofluidic platform (Fluidigm©, San Francisco, CA, USA). As a clinical assessment, tracheal swabs were sampled from turkeys showing RS and submitted to this panel assay. Beside systematic detection of E. coli, avian metapneumovirus, Mycoplasma gallisepticum and Mycoplasma synoviae were frequently detected, with distinctive co-infection patterns between French and Moroccan flocks. This proof-of-concept study illustrates the potential of such panel assays for unveiling respiratory co-infection profiles in poultry.

Respiratory Morbidity among Rice Mill Workers in an Urban Area of Burdwan District, West Bengal: A Cross-sectional Study.

PubMed

Rana, Madhab Ch; Naskar, Somnath; Roy, Ramaprasad; Das, Dilip Kr; Das, Soumya

2018-01-01

Rice mill workers constitute a special group from the perspective of occupational health. Unprotected dust exposure among them adversely affects their respiratory health, which needs to be evaluated. Adequate evidence is still lacking in many parts of India including West Bengal. Burdwan is one of the main rice-producing districts in the state with abundant rice mills. The aim of the study was to find out the prevalence and pattern of respiratory morbidity and associated background characteristics of rice mill workers. A descriptive cross-sectional study was conducted at Burdwan municipality area during July-December 2016. Considering 44.2% prevalence, 95% confidence interval, 15% allowable error, 10% non-response, a sample of 252 directly engaged rice mill workers were selected through multistage random sampling. With prior consent, the subjects were interviewed, clinically examined, and underwent spirometry; relevant records were also reviewed using a pre-designed schedule. Any abnormal spirometry finding was considered as respiratory morbidity. Ethical approval was obtained from institutional ethics committee. Data were analyzed using SPSS version 20. Chi-square test and multiple logistic regression were applied. Prevalence of respiratory morbidity was 40.73% with obstructive and restrictive respiratory morbidity being 24.60% and 16.13%, respectively. Non-use of any protective measure, duration (years) of working in rice mill and average daily working hours were significant predictors of respiratory morbidity. Respiratory morbidity is quite high in the area. Proper health education and provision of personal protective equipments need to be provided.

Respiratory modulation of sympathetic nerve activity is enhanced in male rat offspring following uteroplacental insufficiency.

PubMed

Menuet, C; Wlodek, M E; Fong, A Y; Allen, A M

2016-06-01

Sympathetic nerve activity to the cardiovascular system displays prominent respiratory-related modulation which leads to the generation of rhythmic oscillations in blood pressure called Traube-Hering waves. An amplification of this respiratory modulation of sympathetic activity is observed in hypertension of both genetic, the spontaneously hypertensive rat, and induced, chronic intermittent hypoxia or maternal protein restriction during gestation, origin. Male offspring of mothers with uteroplacental insufficiency, induced by bilateral uterine vessel ligation at 18 days of gestation, are also hypertensive in adulthood. In this study we examined whether these male offspring display altered respiratory modulation of sympathetic activity at pre-hypertensive ages compared to controls. Respiratory, cardiovascular and sympathetic parameters were examined using the working heart-brainstem preparation in 35 day old male rats that had reduced birth weight due to uteroplacental insufficiency. Whilst all respiratory parameters were not different between groups, we observed an enhanced respiratory-related burst of thoracic sympathetic nerve activity and amplified Traube-Hering waves in the growth-restricted group. This group also showed an increased sympathetic and bradycardic response to activation of peripheral chemoreceptors. The observations add support to the view that altered respiratory modulation of sympathetic activity represents a common mechanism involved in the development of several forms of hypertension. Copyright © 2015 Elsevier B.V. All rights reserved.

Sympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Myers, C. W.; Halliwill, J. R.; Seidel, H.; Eckberg, D. L.

2001-01-01

Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 frequencies, from 15 to 3 breaths/min, before and after beta-adrenergic blockade. We fitted changes of respiratory frequency R-R interval spectral power with a damped oscillator model: frequency-dependent oscillations with a resonant frequency, generated by driving forces and modified by damping influences. beta-Adrenergic blockade enhanced respiratory sinus arrhythmia at all frequencies (at some, fourfold). The damped oscillator model fit experimental data well (39 of 40 ramps; r = 0.86 +/- 0.02). beta-Adrenergic blockade increased respiratory sinus arrhythmia by amplifying respiration-related driving forces (P < 0.05), without altering resonant frequency or damping influences. Both spectral power data and the damped oscillator model indicate that cardiac sympathetic outflow markedly reduces heart period oscillations at all frequencies. This challenges the notion that respiratory sinus arrhythmia is mediated simply by vagal-cardiac nerve activity. These results have important implications for clinical and experimental estimation of human vagal cardiac tone.

Multigenerational links between mothers' experiences of autonomy in childhood and preschoolers' respiratory sinus arrhythmia: Variations by maltreatment status.

PubMed

Noll, Laura K; Clark, Caron A C; Skowron, Elizabeth A

2015-11-01

Despite burgeoning evidence linking early exposure to child maltreatment (CM) to deficits in self-regulation, the pathways to strong regulatory development in these children are not well understood, and significant heterogeneity is observed in their outcomes. Experiences of autonomy may play a key role in transmitting self-regulatory capacity across generations and help explain individual differences in maltreatment outcomes. In this study, we investigated multigenerational associations between Generation 1 (G1)-Generation 2 (G2) mothers' early experience of warmth and autonomy in relation to their own mothers and their Generation 3 (G3) children's autonomic physiological regulation in CM (n = 85) and non-CM (n = 128) families. We found that G2 mothers who recalled greater autonomy in their childhood relationship with their G1 mothers had preschool-age G3 children with higher respiratory sinus arrhythmia at baseline when alone while engaged in individual challenge tasks, during social exchanges with their mother in joint challenge tasks, and during the portions of the strange situation procedure when the mother was present. Although no clear mediators of this association emerged, multigenerational links among G1-G2 relations, maternal representations of her child, child behavior, and child respiratory sinus arrhythmia differed by maltreatment status, thus possibly representing important targets for future research and intervention.

Multigenerational links between mothers’ experiences of autonomy in childhood and preschoolers’ respiratory sinus arrhythmia: Variations by maltreatment status

PubMed Central

NOLL, LAURA K.; CLARK, CARON A. C.; SKOWRON, ELIZABETH A.

2017-01-01

Despite burgeoning evidence linking early exposure to child maltreatment (CM) to deficits in self-regulation, the pathways to strong regulatory development in these children are not well understood, and significant heterogeneity is observed in their outcomes. Experiences of autonomy may play a key role in transmitting self-regulatory capacity across generations and help explain individual differences in maltreatment outcomes. In this study, we investigated multigenerational associations between Generation 1 (G1)–Generation 2 (G2) mothers’ early experience of warmth and autonomy in relation to their own mothers and their Generation 3 (G3) children’s autonomic physiological regulation in CM (n = 85) and non-CM (n = 128) families. We found that G2 mothers who recalled greater autonomy in their childhood relationship with their G1 mothers had preschool-age G3 children with higher respiratory sinus arrhythmia at baseline when alone while engaged in individual challenge tasks, during social exchanges with their mother in joint challenge tasks, and during the portions of the strange situation procedure when the mother was present. Although no clear mediators of this association emerged, multigenerational links among G1–G2 relations, maternal representations of her child, child behavior, and child respiratory sinus arrhythmia differed by maltreatment status, thus possibly representing important targets for future research and intervention. PMID:26535936

Positive selection results in frequent reversible amino acid replacements in the G protein gene of human respiratory syncytial virus.

PubMed

Botosso, Viviane F; Zanotto, Paolo M de A; Ueda, Mirthes; Arruda, Eurico; Gilio, Alfredo E; Vieira, Sandra E; Stewien, Klaus E; Peret, Teresa C T; Jamal, Leda F; Pardini, Maria I de M C; Pinho, João R R; Massad, Eduardo; Sant'anna, Osvaldo A; Holmes, Eddie C; Durigon, Edison L

2009-01-01

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a "flip-flop" phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.

Evaluation of the new respiratory gating system

PubMed Central

Shi, Chengyu; Tang, Xiaoli; Chan, Maria

2018-01-01

Objective The newly released Respiratory Gating for Scanners (RGSC; Varian Medical Systems, Palo Alto, CA, USA) system has limited existing quality assurance (QA) protocols and pertinent publications. Herein, we report our experiences of the RGSC system acceptance and QA. Methods The RGSC system integration was tested with peripheral equipment, spatial reproducibility, and dynamic localization accuracy for regular and irregular breathing patterns, respectively. A QUASAR Respiratory Motion Phantom and a mathematical fitting method were used for data acquisition and analysis. Results The results showed that the RGSC system could accurately measure regular motion periods of 3–10 s. For irregular breathing patterns, differences from the existing Real-time Position Management (RPM; Varian Medical Systems, Palo Alto, CA) system were observed. For dynamic localization measurements, the RGSC system showed 76% agreement with the programmed test data within ±5% tolerance in terms of fitting period. As s comparison, the RPM system showed 66% agreement within ±5% tolerance, and 65% for the RGSC versus RPM measurements. Conclusions New functions and positioning accuracy improve the RGSC system’s ability to achieve higher dynamic treatment precision. A 4D phantom is helpful for the QA tests. Further investigation is required for the whole RGSC system performance QA. PMID:29722356

Concurrent respiratory resistance training and changes in respiratory muscle strength and sleep in an individual with spinal cord injury: case report

PubMed Central

Russian, Chris; Litchke, Lyn; Hudson, John

2011-01-01

Context Quality sleep possesses numerous benefits to normal nighttime and daytime functioning. High-level spinal cord injury (SCI) often impacts the respiratory muscles that can lead to poor respiratory function during sleep and negatively affect sleep quality. The impact of respiratory muscle training (RMT) on sleep quality, as assessed by overnight polysomnography (PSG), is yet to be determined among the spinal cord-injured population. This case report describes the effects of 10 weeks of RMT on the sleep quality of a 38-year-old male with cervical SCI. Methods Case report. Findings/results The subject completed overnight PSG, respiratory muscle strength assessment, and subjective sleepiness assessment before and after 10 weeks of RMT. The post-test results indicated improvements in sleep quality (e.g. fewer electroencephalographic (EEG) arousals during sleep) and daytime sleepiness scores following RMT. Conclusion/clinical relevance Respiratory activity has been proven to impact EEG arousal activity during sleep. Arousals during sleep lead to a fragmented sleeping pattern and affect sleep quality and daytime function. Our subject presented with a typical sleep complaint of snoring and excessive sleepiness. The subject's pre-test PSG demonstrated a large number of arousals during sleep. It is important for all individuals complaining of problems during sleep or daytime problems associated with sleep (i.e. excessive daytime sleepiness) to seek medical attention and proper evaluation. PMID:21675365

Locomotor-respiratory coupling during axillary crutch ambulation.

PubMed

Hurst, C A; Kirby, R L; MacLeod, D A

2001-11-01

To test the hypotheses that locomotor-respiratory coupling occurs in humans using axillary crutches in a swing-through ambulation pattern and that expiration occurs during crutch-stance phase during locomotor-respiratory coupling. Eighteen able-bodied persons were trained in one-footed swing-through gait with axillary crutches. Then, as subjects walked at "somewhat hard" speeds (Borg) on a motorized treadmill for 5 min, we recorded signals from a crutch pressure switch and a mouthpiece-mounted thermocouple. Coupling was defined as being present when the onset of inspiration varied by < or = 5% with respect to the onset of the crutch gait cycle for a minimum of 10 consecutive gait cycles and when there was no drift on a raster plot of the respiratory phases relative to the onset of the gait cycle. Ten (56%) of the 18 subjects exhibited locomotor-respiratory coupling on 1-4 occasions each, with episodes lasting 11.3-148 sec. In 17 (89%) of the 19 episodes of 1:1 locomotor-respiratory coupling, expiration occurred during the crutch-stance phase of the gait cycle and inspiration occurred during crutch swing. Transient 1:1 locomotor-respiratory coupling occurs in many able-bodied subjects ambulating with axillary crutches and a swing-through gait. Expiration is most often associated with the crutch-stance phase of the gait cycle. This study may have implications for training axillary crutch users.

An observational study of PM10 and hospital admissions for acute exacerbations of chronic respiratory disease in Tasmania, Australia 1992-2002.

PubMed

Mészáros, D; Markos, J; FitzGerald, D G; Walters, E H; Wood-Baker, R

2015-01-01

Particulate matter with a diameter below 10 µ (PM10) has been a major concern in the Tamar Valley, Launceston, where wood heaters are extensively used. We examined the relationship between PM10 levels, meteorological variables, respiratory medications and hospital admissions for respiratory disease over the decade 1992-2002. PM10 levels were provided by the Department of Primary Industry Water, Parks and Environment, and meteorological variables from the Bureau of Meteorology. We obtained hospital discharge codes for the Launceston General Hospital. Poisson regression was used for statistical analyses. Mean daily PM10 levels declined from 50.7 to 16.5 μg/m(3). Hospitalisations for asthma decreased from 29 to 21 per month, whereas chronic obstructive pulmonary disease (COPD) increased and bronchitis/bronchiolitis remained unchanged. We found a 10 μg/m(3) increase in PM10 to be associated with a 4% increase in admissions for acute bronchitis/bronchiolitis (p0.05), but no association with asthma or COPD was found. All respiratory diseases showed seasonal patterns of hospitalisation. This is the first long-term study in Australia to demonstrate an association between PM10 levels and respiratory diseases. Reducing exposure to PM10 may decrease hospital admissions for respiratory diseases. Better preventive measures, including sustained public health initiatives to combat air pollution, are required to reduce respiratory morbidity.

[Aluminium in the lower respiratory tract of people living in México City].

PubMed

Manquián-Tejos, Adelaida R I; Tovar-Gálvez, Luis R; Yáñez-Canal, Gabriel

2008-01-01

Investigating the presence of aluminium (Al) and respiratory pathologies in the lower respiratory tract of people who had lived in Mexico City for a minimum of two years. 250 respiratory tissue samples were obtained from pulmonary lobes, lymph nodes, bronchial and hilum regions during 36 individuals' autopsies. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for quantifying Al; the samples has been previously dried, ground and digested. 13 different pathologies were identified but only three of them (pulmonary emphysema, bronchitis and anthracosis) were correlated with the presence of Al, an element being distributed in very variable concentrations (range: 2.7 to 836.1 micrograms of Al per gram of dry tissue (ì g Al/g ts)). The amount of Al found in lobes, bronchial and hilum regions was much smaller than that found in lymph nodes; such difference was statistically significant. Multivariate analysis by conglomerates revealed that the sample consisted of three classes of individuals, grouped according to the amount and distribution of Al in the lower respiratory tract, age, time spent living in Mexico City and the presence of pathologies. The Al found in the lower respiratory tract of residents of Mexico City would thus seem to have come from the air. The amount of Al and its distribution pattern depended on the time and place of residence and can lead to respiratory illness.

Central respiratory effects of substance P in neonatal mice: an in vitro study.

PubMed

Ptak, K; Hilaire, G

1999-05-14

Experiments were performed on neonatal mice to know whether substance P (SP) modified the rhythm and the amplitude of the phrenic bursts generated in vitro in brainstem-cervical cord preparations. In OF1 and C3H neonatal preparations, SP or the tachykinin NK1 receptor agonist [Sar9,Met(O2)11] substance P both increased significantly phrenic burst amplitude (10(-7) M) but had no significant effect on respiratory rhythm unless used at concentrations 10 times larger. In neonates from the monoamine oxidase-A deficient transgenic Tg8 line, SP increased phrenic burst amplitude but had no effect on the respiratory rhythm at the tested concentrations. The role of SP in regulating neonatal respiratory activity is discussed on the basis of rat and mouse results.

A one-year community study of under-fives in rural Ethiopia: patterns of morbidity and public health risk factors.

PubMed

Muhe, L; Byass, P; Freij, L; Sandström, A; Wall, S

1995-03-01

A prospective weekly home surveillance study was undertaken to determine morbidity patterns within the Butajira Rural Health project in central Ethiopia. Overall prevalence of illness was 5.8% in 1216 person-years observed among rural Ethiopian children aged under 5 years. Acute respiratory infections (ARI) (prevalence 2.8%) and acute diarrhoea (2.4%) were the commonest conditions. Episodes of illness were distributed unequally among children, with a mean of 2.34 episodes per child. These included an average of 1.13 episodes of ARI (of which 0.16 had lower respiratory symptoms [ALRI]) and 1.17 episodes of acute diarrhoea. Sanitation factors were the principal risks for gastroenteritis, while living in rural areas predisposed children to ARI. Parental factors such as illiteracy were also linked to morbidity.

Cardiovascular, electrodermal, and respiratory response patterns to fear- and sadness-inducing films.

PubMed

Kreibig, Sylvia D; Wilhelm, Frank H; Roth, Walton T; Gross, James J

2007-09-01

Responses to fear- and sadness-inducing films were assessed using a broad range of cardiovascular (heart rate, T-wave amplitude, low- and high-frequency heart rate variability, stroke volume, preejection period, left-ventricular ejection time, Heather index, blood pressure, pulse amplitude and transit time, and finger temperature), electrodermal (level, response rate, and response amplitude), and respiratory (rate, tidal volume and its variability, inspiratory flow rate, duty cycle, and end-tidal pCO(2)) measures. Subjective emotional experience and facial behavior (Corrugator Supercilii and Zygomaticus Major EMG) served as control measures. Results indicated robust differential physiological response patterns for fear, sadness, and neutral (mean classification accuracy 85%). Findings are discussed in terms of the fight-flight and conservation-withdrawal responses and possible limitations of a valence-arousal categorization of emotion in affective space.

Efficacy of ventilator waveform observation for detection of patient-ventilator asynchrony during NIV: a multicentre study.

PubMed

Longhini, Federico; Colombo, Davide; Pisani, Lara; Idone, Francesco; Chun, Pan; Doorduin, Jonne; Ling, Liu; Alemani, Moreno; Bruni, Andrea; Zhaochen, Jin; Tao, Yu; Lu, Weihua; Garofalo, Eugenio; Carenzo, Luca; Maggiore, Salvatore Maurizio; Qiu, Haibo; Heunks, Leo; Antonelli, Massimo; Nava, Stefano; Navalesi, Paolo

2017-10-01

The objective of this study was to assess ability to identify asynchronies during noninvasive ventilation (NIV) through ventilator waveforms according to experience and interface, and to ascertain the influence of breathing pattern and respiratory drive on sensitivity and prevalence of asynchronies. 35 expert and 35 nonexpert physicians evaluated 40 5-min NIV reports displaying flow-time and airway pressure-time tracings; identified asynchronies were compared with those ascertained by three examiners who evaluated the same reports displaying, additionally, tracings of diaphragm electrical activity. We determined: 1) sensitivity, specificity, and positive and negative predictive values; 2) the correlation between the double true index (DTI) of each report ( i.e., the ratio between the sum of true positives and true negatives, and the overall breath count) and the corresponding asynchrony index (AI); and 3) the influence of breathing pattern and respiratory drive on both AI and sensitivity. Sensitivities to detect asynchronies were low either according to experience (0.20 (95% CI 0.14-0.29) for expert versus 0.21 (95% CI 0.12-0.30) for nonexpert, p=0.837) or interface (0.28 (95% CI 0.17-0.37) for mask versus 0.10 (95% CI 0.05-0.16) for helmet, p<0.0001). DTI inversely correlated with the AI (r 2 =0.67, p<0.0001). Breathing pattern and respiratory drive did not affect prevalence of asynchronies and sensitivity. Patient-ventilator asynchrony during NIV is difficult to recognise solely by visual inspection of ventilator waveforms.

A Holistic Approach to Climate and Health Research: Respiratory and Infectious Diseases

NASA Astrophysics Data System (ADS)

Asrar, G.; Alonoso, W.; McCormick, B.; Schuck-Paim, C.; Miller, M.

2014-12-01

The link between climate variability and change, especially extreme conditions, is well documented in both environmental and health literature. The focus of research in the recent past, and current studies, is to understand causal relationships between the disease agents and environmental conditions, based on post-hoc analysis of observed cases to develop predictive models for advance warning of public by health authorities. A combination of the isolated examination of individual diseases and routes of infection (e.g. respiratory system, skin, digestive tract, etc.) and reliance mostly on correlative evidence from past occurrences have restricted public health progress (e.g. compared to experimental evidence of the quantitative balance of different transmission routes) and the utility of knowledge gained from such studies (e.g. reliably predicting seasonal outbreaks is no longer an advance). We propose a shift from focusing on the prediction of individual disease pattern(s) to a more holistic identification and mitigation of broader vulnerabilities within the provision of public health. Such an approach has the potential to account for and reveal health vulnerabilities common to a broader range of health stresses, thus facilitating a more holistic response to health challenges. The human health fragilities associated with respiratory diseases caused by a combination of natural (i.e dust, pollen, etc.) and industrial particulates (i.e. soot, aerosols, etc.) and other infectious airborne agents, for example, and their adverse impact on human health such as respiratory, gastrointestinal, etc. is an ideal candidate for such a holistic approach to environment and health research.

Cytokine patterns in paediatric patients presenting serious gastrointestinal and respiratory bacterial infections

PubMed Central

Palacios-Martínez, Monika; Rodríguez-Cruz, Leonor; Cortés-Bejar, Consuelo Del Carmen; Valencia-Chavarría, Fernando; Martínez-Gómez, Daniel; González-Torres, María Cristina

2014-01-01

In the adaptive immune response, the types of cytokines produced define whether there is a cellular (T1) or a humoral (T2) response. Specifically, in the T1 response, interleukin 2 (IL-2), interferon γ (IFN-γ) and tumor necrosis factor β (TNF-β) are produced, whereas in the T2 response, IL-4, IL-5, IL- 6, IL-10 and IL-13 are primarily produced. Cytokines are primarily involved in the regulation of immune system cells. The aim of the present study was to evaluate the cytokine patterns (Type 1/Type 2) and TNF-α expression levels in children with severe gastrointestinal and respiratory bacterial infections. The enzyme-linked immunosorbent assay (ELISA) technique was used to identify the cytokines and the infectious agents. The results obtained demonstrated that, in general, children with bacterial infections experienced an increase in IL-2, IFN-γ and IL-4 concentrations and a decrease in TNF-α, IL-5 and IL-6 concentrations when compared to healthy children. Specifically, type 1 cytokines and an increased TNF-α concentration were found in children with gastrointestinal infections. However, patients with respiratory infections showed increased concentrations of both T2 (IL-4, IL-6 and IL-10) and T1 (IL-2 and IFN-γ) components. Thus, it was concluded that children with gastrointestinal infections exclusively developed a T1 response, whereas children with respiratory infections developed a T1/T2 response to fight the infection. PMID:26155128

SU-F-J-117: Impact of Motion Artifacts On Image Quality and Accuracy of Tumor Motion Reconstruction in 4D CT-On-Rails and MV-CBCT Scans: A Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, T; Ma, C

Purpose: To compare and quantify respiratory motion artifacts in images from free breathing 4D-CT-on-Rails(CTOR) and those from MV-Cone-beam-CT(MVCB) and facilitate respiratory motion guided radiation therapy. Methods: 4D-CTOR: Siemens Somatom CT-on-Rails system with Anzai belt loaded with pressure sensor load cells. 4D scans were performed in helical mode, pitch 0.1, gantry rotation time 0.5s, 1.5mm slice thickness, 120kVp, 400 mAs. Normal and fast breathing (>12rpm) scanning protocols were investigated. Helical scan, AIP(average intensity projection) and MIP(maximum intensity projection) were generated from 4D-CTOR scans with amplitude sorting into 10 phases.MVCB: Siemens Artiste diamond view(1MV)MVCB was performed with 5MU thorax protocol with 60more » second of full rotation.Phantom: Anzai AZ-733V respiratory phantom. The settings were set to normal and resp. modes with repetition rates at 15 rpm and 10 rpm. Surgical clips, acrylic, wooden, rubber and lung density, total six mock-ups were scanned and compared in this study.Signal-to-noise ratio(SNR), contrast-to-noise ratio(CNR) and reconstructed motion volume were compared to different respiratory setups for the mock-ups. Results: Reconstructed motion volume was compared to the real object volume for the six test mock-ups. It shows that free breathing helical in all instances underestimates the object excursions largest to −67.4% and least −6.3%. Under normal breathing settings, MIP can predict very precise motion volume with minimum 0.4% and largest −13.9%. MVCB shows underestimate of the motion volume with −1.11% minimum and −18.0% maximum. With fast breathing, AIP provides bad representation of the object motion; however, the MIP can predict the motion volume with −2.0% to −11.4% underestimate. Conclusion: Respiratory motion guided radiation therapy requires good motion recording. This study shows that regular CTOR helical scans provides bad guidance, 4D CTOR AIP cannot represent the fast breathing pattern, MIP can represent the best motion volume, MVCBCT can only be used for normal breathing with acceptable uncertainties.« less

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates.

PubMed

Taylor, Edwin W; Leite, Cleo A C; Sartori, Marina R; Wang, Tobias; Abe, Augusto S; Crossley, Dane A

2014-03-01

Heart rate in vertebrates is controlled by activity in the autonomic nervous system. In spontaneously active or experimentally prepared animals, inhibitory parasympathetic control is predominant and is responsible for instantaneous changes in heart rate, such as occur at the first air breath following a period of apnoea in discontinuous breathers like inactive reptiles or species that surface to air breathe after a period of submersion. Parasympathetic control, exerted via fast-conducting, myelinated efferent fibres in the vagus nerve, is also responsible for beat-to-beat changes in heart rate such as the high frequency components observed in spectral analysis of heart rate variability. These include respiratory modulation of the heartbeat that can generate cardiorespiratory synchrony in fish and respiratory sinus arrhythmia in mammals. Both may increase the effectiveness of respiratory gas exchange. Although the central interactions generating respiratory modulation of the heartbeat seem to be highly conserved through vertebrate phylogeny, they are different in kind and location, and in most species are as yet little understood. The heart in vertebrate embryos possesses both muscarinic cholinergic and β-adrenergic receptors very early in development. Adrenergic control by circulating catecholamines seems important throughout development. However, innervation of the cardiac receptors is delayed and first evidence of a functional cholinergic tonus on the heart, exerted via the vagus nerve, is often seen shortly before or immediately after hatching or birth, suggesting that it may be coordinated with the onset of central respiratory rhythmicity and subsequent breathing.

Cellular defense of the avian respiratory system: effects of Pasteurella multocida on respiratory burst activity of avian respiratory tract phagocytes.

PubMed

Ochs, D L; Toth, T E; Pyle, R H; Siegel, P B

1988-12-01

The respiratory tract of healthy chickens contain few free-residing phagocytic cells. Intratracheal inoculation with Pasteurella multocida stimulated a significant (P less than 0.05) migration of cells to the lungs and air sacs of White Rock chickens within 2 hours after inoculation. We found the maximal number of avian respiratory tract phagocytes (22.9 +/- 14.0 x 10(6] at 8 hours after inoculation. Flow cytometric analysis of these cells revealed 2 populations on the basis of cell-size and cellular granularity. One of these was similar in size and granularity to those of blood heterophils. Only this population was capable of generating oxidative metabolites in response to phorbol myristate acetate. The ability of the heterophils to produce hydrogen peroxide, measured as the oxidation of intracellularly loaded 2',7'-dichlorofluorescein, decreased with time after inoculation. These results suggest that the migration of heterophils, which are capable of high levels of oxidative metabolism, to the lungs and air sacs may be an important defense mechanism of poultry against bacterial infections of the respiratory tract.

Atoh1-dependent rhombic lip neurons are required for temporal delay between independent respiratory oscillators in embryonic mice

PubMed Central

Tupal, Srinivasan; Huang, Wei-Hsiang; Picardo, Maria Cristina D; Ling, Guang-Yi; Del Negro, Christopher A; Zoghbi, Huda Y; Gray, Paul A

2014-01-01

All motor behaviors require precise temporal coordination of different muscle groups. Breathing, for example, involves the sequential activation of numerous muscles hypothesized to be driven by a primary respiratory oscillator, the preBötzinger Complex, and at least one other as-yet unidentified rhythmogenic population. We tested the roles of Atoh1-, Phox2b-, and Dbx1-derived neurons (three groups that have known roles in respiration) in the generation and coordination of respiratory output. We found that Dbx1-derived neurons are necessary for all respiratory behaviors, whereas independent but coupled respiratory rhythms persist from at least three different motor pools after eliminating or silencing Phox2b- or Atoh1-expressing hindbrain neurons. Without Atoh1 neurons, however, the motor pools become temporally disorganized and coupling between independent respiratory oscillators decreases. We propose Atoh1 neurons tune the sequential activation of independent oscillators essential for the fine control of different muscles during breathing. DOI: http://dx.doi.org/10.7554/eLife.02265.001 PMID:24842997

3D tumor localization through real-time volumetric x-ray imaging for lung cancer radiotherapy.

PubMed

Li, Ruijiang; Lewis, John H; Jia, Xun; Gu, Xuejun; Folkerts, Michael; Men, Chunhua; Song, William Y; Jiang, Steve B

2011-05-01

To evaluate an algorithm for real-time 3D tumor localization from a single x-ray projection image for lung cancer radiotherapy. Recently, we have developed an algorithm for reconstructing volumetric images and extracting 3D tumor motion information from a single x-ray projection [Li et al., Med. Phys. 37, 2822-2826 (2010)]. We have demonstrated its feasibility using a digital respiratory phantom with regular breathing patterns. In this work, we present a detailed description and a comprehensive evaluation of the improved algorithm. The algorithm was improved by incorporating respiratory motion prediction. The accuracy and efficiency of using this algorithm for 3D tumor localization were then evaluated on (1) a digital respiratory phantom, (2) a physical respiratory phantom, and (3) five lung cancer patients. These evaluation cases include both regular and irregular breathing patterns that are different from the training dataset. For the digital respiratory phantom with regular and irregular breathing, the average 3D tumor localization error is less than 1 mm which does not seem to be affected by amplitude change, period change, or baseline shift. On an NVIDIA Tesla C1060 graphic processing unit (GPU) card, the average computation time for 3D tumor localization from each projection ranges between 0.19 and 0.26 s, for both regular and irregular breathing, which is about a 10% improvement over previously reported results. For the physical respiratory phantom, an average tumor localization error below 1 mm was achieved with an average computation time of 0.13 and 0.16 s on the same graphic processing unit (GPU) card, for regular and irregular breathing, respectively. For the five lung cancer patients, the average tumor localization error is below 2 mm in both the axial and tangential directions. The average computation time on the same GPU card ranges between 0.26 and 0.34 s. Through a comprehensive evaluation of our algorithm, we have established its accuracy in 3D tumor localization to be on the order of 1 mm on average and 2 mm at 95 percentile for both digital and physical phantoms, and within 2 mm on average and 4 mm at 95 percentile for lung cancer patients. The results also indicate that the accuracy is not affected by the breathing pattern, be it regular or irregular. High computational efficiency can be achieved on GPU, requiring 0.1-0.3 s for each x-ray projection.

Trends and Patterns of Differences in Chronic Respiratory Disease Mortality Among US Counties, 1980-2014.

PubMed

Dwyer-Lindgren, Laura; Bertozzi-Villa, Amelia; Stubbs, Rebecca W; Morozoff, Chloe; Shirude, Shreya; Naghavi, Mohsen; Mokdad, Ali H; Murray, Christopher J L

2017-09-26

Chronic respiratory diseases are an important cause of death and disability in the United States. To estimate age-standardized mortality rates by county from chronic respiratory diseases. Validated small area estimation models were applied to deidentified death records from the National Center for Health Statistics and population counts from the US Census Bureau, National Center for Health Statistics, and Human Mortality Database to estimate county-level mortality rates from 1980 to 2014 for chronic respiratory diseases. County of residence. Age-standardized mortality rates by county, year, sex, and cause. A total of 4 616 711 deaths due to chronic respiratory diseases were recorded in the United States from January 1, 1980, through December 31, 2014. Nationally, the mortality rate from chronic respiratory diseases increased from 40.8 (95% uncertainty interval [UI], 39.8-41.8) deaths per 100 000 population in 1980 to a peak of 55.4 (95% UI, 54.1-56.5) deaths per 100 000 population in 2002 and then declined to 52.9 (95% UI, 51.6-54.4) deaths per 100 000 population in 2014. This overall 29.7% (95% UI, 25.5%-33.8%) increase in chronic respiratory disease mortality from 1980 to 2014 reflected increases in the mortality rate from chronic obstructive pulmonary disease (by 30.8% [95% UI, 25.2%-39.0%], from 34.5 [95% UI, 33.0-35.5] to 45.1 [95% UI, 43.7-46.9] deaths per 100 000 population), interstitial lung disease and pulmonary sarcoidosis (by 100.5% [95% UI, 5.8%-155.2%], from 2.7 [95% UI, 2.3-4.2] to 5.5 [95% UI, 3.5-6.1] deaths per 100 000 population), and all other chronic respiratory diseases (by 42.3% [95% UI, 32.4%-63.8%], from 0.51 [95% UI, 0.48-0.54] to 0.73 [95% UI, 0.69-0.78] deaths per 100 000 population). There were substantial differences in mortality rates and changes in mortality rates over time among counties, and geographic patterns differed by cause. Counties with the highest mortality rates were found primarily in central Appalachia for chronic obstructive pulmonary disease and pneumoconiosis; widely dispersed throughout the Southwest, northern Great Plains, New England, and South Atlantic for interstitial lung disease; along the southern half of the Mississippi River and in Georgia and South Carolina for asthma; and in southern states from Mississippi to South Carolina for other chronic respiratory diseases. Despite recent declines in mortality from chronic respiratory diseases, mortality rates in 2014 remained significantly higher than in 1980. Between 1980 and 2014, there were important differences in mortality rates and changes in mortality by county, sex, and particular chronic respiratory disease type. These estimates may be helpful for informing efforts to improve prevention, diagnosis, and treatment.

3D delivered dose assessment using a 4DCT-based motion model

PubMed Central

Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Seco, Joao; Mishra, Pankaj; Lewis, John H.

2015-01-01

Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT). Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps. (1) At the treatment planning stage, a patient-specific motion model is created from planning 4DCT data. This model assumes that the displacement vector field (DVF) of any respiratory motion deformation can be described as a linear combination of some basis DVFs. (2) During the treatment procedure, 2D time-varying projection images (either kV or MV projections) are acquired, from which time-varying “fluoroscopic” 3D images of the patient are reconstructed using the motion model. The DVF of each timepoint in the time-varying reconstruction is an optimized linear combination of basis DVFs such that the 2D projection of the 3D volume at this timepoint matches the projection image. (3) 3D dose distribution is computed for each timepoint in the set of 3D reconstructed fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach was first validated using two modified digital extended cardio-torso (XCAT) phantoms with lung tumors and different respiratory motions. The estimated doses were compared to the dose that would be calculated for routine 4DCT-based planning and to the actual delivered dose that was calculated using “ground truth” XCAT phantoms at all timepoints. The approach was also tested using one set of patient data, which demonstrated the application of our method in a clinical scenario. Results: For the first XCAT phantom that has a mostly regular breathing pattern, the errors in 95% volume dose (D95) are 0.11% and 0.83%, respectively for 3D fluoroscopic images reconstructed from kV and MV projections compared to the ground truth, which is clinically comparable to 4DCT (0.093%). For the second XCAT phantom that has an irregular breathing pattern, the errors are 0.81% and 1.75% for kV and MV reconstructions, both of which are better than that of 4DCT (4.01%). In the case of real patient, although it is impossible to obtain the actual delivered dose, the dose estimation is clinically reasonable and demonstrates differences between 4DCT and MV reconstruction-based dose estimates. Conclusions: With the availability of kV or MV projection images, the proposed approach is able to assess delivered doses for all respiratory phases during treatment. Compared to the planning dose based on 4DCT, the dose estimation using reconstructed 3D fluoroscopic images was as good as 4DCT for regular respiratory pattern and was a better dose estimation for the irregular respiratory pattern. PMID:26127043

3D delivered dose assessment using a 4DCT-based motion model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.

Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT). Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps. (1) At the treatment planning stage, a patient-specific motion model is created from planning 4DCT data. This model assumes that the displacement vector field (DVF) of any respiratory motion deformation can be described as a linear combination of some basismore » DVFs. (2) During the treatment procedure, 2D time-varying projection images (either kV or MV projections) are acquired, from which time-varying “fluoroscopic” 3D images of the patient are reconstructed using the motion model. The DVF of each timepoint in the time-varying reconstruction is an optimized linear combination of basis DVFs such that the 2D projection of the 3D volume at this timepoint matches the projection image. (3) 3D dose distribution is computed for each timepoint in the set of 3D reconstructed fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach was first validated using two modified digital extended cardio-torso (XCAT) phantoms with lung tumors and different respiratory motions. The estimated doses were compared to the dose that would be calculated for routine 4DCT-based planning and to the actual delivered dose that was calculated using “ground truth” XCAT phantoms at all timepoints. The approach was also tested using one set of patient data, which demonstrated the application of our method in a clinical scenario. Results: For the first XCAT phantom that has a mostly regular breathing pattern, the errors in 95% volume dose (D95) are 0.11% and 0.83%, respectively for 3D fluoroscopic images reconstructed from kV and MV projections compared to the ground truth, which is clinically comparable to 4DCT (0.093%). For the second XCAT phantom that has an irregular breathing pattern, the errors are 0.81% and 1.75% for kV and MV reconstructions, both of which are better than that of 4DCT (4.01%). In the case of real patient, although it is impossible to obtain the actual delivered dose, the dose estimation is clinically reasonable and demonstrates differences between 4DCT and MV reconstruction-based dose estimates. Conclusions: With the availability of kV or MV projection images, the proposed approach is able to assess delivered doses for all respiratory phases during treatment. Compared to the planning dose based on 4DCT, the dose estimation using reconstructed 3D fluoroscopic images was as good as 4DCT for regular respiratory pattern and was a better dose estimation for the irregular respiratory pattern.« less

Daily isoflurane exposure increases barbiturate insensitivity in medullary respiratory and cortical neurons via expression of ε-subunit containing GABA ARs.

PubMed

Hengen, Keith B; Nelson, Nathan R; Stang, Kyle M; Johnson, Stephen M; Smith, Stephanie M; Watters, Jyoti J; Mitchell, Gordon S; Behan, Mary

2015-01-01

The parameters governing GABAA receptor subtype expression patterns are not well understood, although significant shifts in subunit expression may support key physiological events. For example, the respiratory control network in pregnant rats becomes relatively insensitive to barbiturates due to increased expression of ε-subunit-containing GABAARs in the ventral respiratory column. We hypothesized that this plasticity may be a compensatory response to a chronic increase in inhibitory tone caused by increased central neurosteroid levels. Thus, we tested whether increased inhibitory tone was sufficient to induce ε-subunit upregulation on respiratory and cortical neurons in adult rats. Chronic intermittent increases in inhibitory tone in male and female rats was induced via daily 5-min exposures to 3% isoflurane. After 7d of treatment, phrenic burst frequency was less sensitive to barbiturate in isoflurane-treated male and female rats in vivo. Neurons in the ventral respiratory group and cortex were less sensitive to pentobarbital in vitro following 7d and 30d of intermittent isoflurane-exposure in both male and female rats. The pentobarbital insensitivity in 7d isoflurane-treated rats was reversible after another 7d. We hypothesize that increased inhibitory tone in the respiratory control network and cortex causes a compensatory increase in ε-subunit-containing GABAARs.

Aerobic metabolism in the genus Lactobacillus: impact on stress response and potential applications in the food industry.

PubMed

Zotta, T; Parente, E; Ricciardi, A

2017-04-01

This review outlines the recent advances in the knowledge on aerobic and respiratory growth of lactic acid bacteria, focusing on the features of respiration-competent lactobacilli. The species of the genus Lactobacillus have been traditionally classified as oxygen-tolerant anaerobes, but it has been demonstrated that several strains are able to use oxygen as a substrate in reactions mediated by flavin oxidases and, in some cases, to synthesize a minimal respiratory chain. The occurrence of genes related to aerobic and respiratory metabolism and to oxidative stress response apparently correlates with the taxonomic position of lactobacilli. Members of the ecologically versatile Lactobacillus casei, L. plantarum and L. sakei groups are apparently best equipped to deal with aerobic/respiratory growth. The shift from anaerobic growth to aerobic (oxygen) and/or respiratory promoting (oxygen, exogenous haem and menaquinone) conditions offers physiological advantages and affects the pattern of metabolite production in several species. Even if this does not result in dramatic increases in biomass production and growth rate, cells grown in these conditions have improved tolerance to heat and oxidative stresses. An overview of benefits and of the potential applications of Lactobacillus cultures grown under aerobic or respiratory conditions is also discussed. © 2017 The Society for Applied Microbiology.

Evaluation of the MEMS based portable respiratory training system with a tactile sensor for respiratory-gated radiotherapy

NASA Astrophysics Data System (ADS)

Moon, Sun Young; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

2017-10-01

In respiratory-gated radiotherapy, it is important to maintain the regular respiratory cycles of patients. If patients undergo respiration training, their regular breathing pattern is affected. Therefore, we developed a respiratory training system based on a micro electromechanical system (MEMS) and evaluated the feasibility of the MEMS in radiotherapy. By comparing the measured signal before and after radiation exposure, we confirmed the effects of radiation. By evaluating the period of the electric signal emitted by a tactile sensor and its constancy, the performance of the tactile sensor was confirmed. Moreover, by comparing the delay between the motion of the MEMS and the electric signal from the tactile sensor, we confirmed the reaction time of the tactile sensor. The results showed that a baseline shift occurred for an accumulated dose of 400 Gy in the sensor, and both the amplitude and period changed. The period of the signal released by the tactile sensor was 5.39 and its standard deviation was 0.06. Considering the errors from the motion phantom, a standard deviation of 0.06 was desirable. The delay time was within 0.5 s and not distinguishable by a patient. We confirmed the performance of the MEMS and concluded that MEMS could be applied to patients for respiratory-gated radiotherapy.

Measurement of nanoparticle exposure in crematoriums and estimation of respiratory deposition of the nanoparticles by number and size distribution.

PubMed

Kato, Nobuyuki; Mastui, Yasuto; Takaoka, Masaki; Yoneda, Minoru

2017-11-25

Nanoparticles (NPs), including hazardous substances, are generated in crematoriums due to the high temperatures during the combustion process. NPs are reported to greatly impact animals' health by reaching the alveoli and being carried to the entire body through the blood stream. However, studies in crematoriums have yet to assess workers' exposure to the generated NPs. The purpose of this study is to assess workers' exposure to NPs released in crematoriums. Field surveys were conducted in three crematoriums with an emphasis on cremation, bone rearrangement and cleaning processes. The NP concentrations and size distributions were analyzed. The deposition of NPs in each respiratory region during each working process was calculated based on the measured data using the Human Respiratory Tract Model. The mean particle number concentration was maximized momentarily during the bone rearrangement process. The concentration at the time a crematory's door was opened was 500,000 particle/cm 3 . NPs aggregated to micro-sized particles within a few minutes, dust generated by the bone rearrangement, or both. As a result of model calculation, the mean ratios (alveolar per the other regions by a crematory) were approximately 3.0 (bronchus and bronchioles regions: except for the first survey in crematorium A which had the obstruction of measurement) and 4.3 (extrathoracic airways). The ratios were similar for all crematoriums. These results can be used for health risk assessments in crematoriums. In addition, these results should be applicable to estimate the inhalation unit risk of each respiratory organ such as lungs and nose.

Dynamical systems techniques reveal the sexual dimorphic nature of motor patterns in birdsong

NASA Astrophysics Data System (ADS)

Mendez, J. M.; Alliende, J. A.; Amador, A.; Mindlin, G. B.

2006-10-01

In this work we analyze the pressure motor patterns used by canaries (Serinus canaria) during song, both in the cases of males and testosterone treated females. We found a qualitative difference between them which was not obvious from the acoustical features of the uttered songs. We also show the diversity of patterns, both for males and females, to be consistent with a recently proposed model for the dynamics of the oscine respiratory system. The model not only allows us to reproduce qualitative features of the different pressure patterns, but also to account for all the diversity of pressure patterns found in females.

Theoretical deposition of carcinogenic particle aggregates in the upper respiratory tract.

PubMed

Sturm, Robert

2013-10-01

Numerous particles suspended in the atmosphere are composed of smaller particular components that form aggregates with highly irregular shape. Such aggregates, among which dusts and soot are the most prominent examples, may be taken up into the respiratory tract and, in the worst case, initiate a malignant transformation of lung cells. Particle aggregates were theoretically modelled by using small spheres with equal diameters (1 nm) and arranging them randomly. This procedure resulted in the generation of various aggregate shapes (chain-like, loose, compact), for which essential parameters such as dynamic shape factors, χ, and aerodynamic diameters, dae , were computed. Deposition of aggregates consisting of 10, 50, 100, and 1,000 nano-spheres was simulated for the uppermost parts of the human respiratory system (extrathoracic region and airway generation 0 to 4), thereby distinguishing between sitting and light-work breathing as well as between nasal and oral inhalation. Based upon the modelling results, aggregate deposition in the human respiratory system can be described as a function of (I) aerodynamic diameter; (II) inhaled particle position within the airway system; and (III) breathing conditions. Therefore, highest deposition values were obtained for nano-scale aggregates (<10 nm), whereas larger aggregates exhibited slightly to significantly reduced deposition probabilities. Extrathoracic regions and uppermost bronchi (generations 0 to 1) were marked by most effective particle capture. Any increase of inhaled air volumes and reduction of breathing times resulted in an enhancement of deposition probabilities of larger particles. Based on the results derived from this study it may be concluded that small particle aggregates are accumulated in the uppermost compartments of the human respiratory tract, where they may unfold their unwholesome potential. In the case of carcinogenic particles being stored in epithelial cells for a longer time span, malignant transformations starting with the formation of cancerous cells and ending with the growth of a tumour have to be assumed.

Automated analysis of connected speech reveals early biomarkers of Parkinson's disease in patients with rapid eye movement sleep behaviour disorder.

PubMed

Hlavnička, Jan; Čmejla, Roman; Tykalová, Tereza; Šonka, Karel; Růžička, Evžen; Rusz, Jan

2017-02-02

For generations, the evaluation of speech abnormalities in neurodegenerative disorders such as Parkinson's disease (PD) has been limited to perceptual tests or user-controlled laboratory analysis based upon rather small samples of human vocalizations. Our study introduces a fully automated method that yields significant features related to respiratory deficits, dysphonia, imprecise articulation and dysrhythmia from acoustic microphone data of natural connected speech for predicting early and distinctive patterns of neurodegeneration. We compared speech recordings of 50 subjects with rapid eye movement sleep behaviour disorder (RBD), 30 newly diagnosed, untreated PD patients and 50 healthy controls, and showed that subliminal parkinsonian speech deficits can be reliably captured even in RBD patients, which are at high risk of developing PD or other synucleinopathies. Thus, automated vocal analysis should soon be able to contribute to screening and diagnostic procedures for prodromal parkinsonian neurodegeneration in natural environments.

Lateralization as a symmetry breaking process in birdsong

NASA Astrophysics Data System (ADS)

Trevisan, M. A.; Cooper, B.; Goller, F.; Mindlin, G. B.

2007-03-01

The singing by songbirds is a most convincing example in the animal kingdom of functional lateralization of the brain, a feature usually associated with human language. Lateralization is expressed as one or both of the bird’s sound sources being active during the vocalization. Normal songs require high coordination between the vocal organ and respiratory activity, which is bilaterally symmetric. Moreover, the physical and neural substrate used to produce the song lack obvious asymmetries. In this work we show that complex spatiotemporal patterns of motor activity controlling airflow through the sound sources can be explained in terms of spontaneous symmetry breaking bifurcations. This analysis also provides a framework from which to study the effects of imperfections in the system’ s symmetries. A physical model of the avian vocal organ is used to generate synthetic sounds, which allows us to predict acoustical signatures of the song and compare the predictions of the model with experimental data.

Subcomplexes of Ancestral Respiratory Complex I Subunits Rapidly Turn Over in Vivo as Productive Assembly Intermediates in Arabidopsis*

PubMed Central

Li, Lei; Nelson, Clark J.; Carrie, Chris; Gawryluk, Ryan M. R.; Solheim, Cory; Gray, Michael W.; Whelan, James; Millar, A. Harvey

2013-01-01

Subcomplexes of mitochondrial respiratory complex I (CI; EC 1.6.5.3) are shown to turn over in vivo, and we propose a role in an ancestral assembly pathway. By progressively labeling Arabidopsis cell cultures with 15N and isolating mitochondria, we have identified CI subcomplexes through differences in 15N incorporation into their protein subunits. The 200-kDa subcomplex, containing the ancestral γ-carbonic anhydrase (γ-CA), γ-carbonic anhydrase-like, and 20.9-kDa subunits, had a significantly higher turnover rate than intact CI or CI+CIII2. In vitro import of precursors for these CI subunits demonstrated rapid generation of subcomplexes and revealed that their specific abundance varied when different ancestral subunits were imported. Time course studies of precursor import showed the further assembly of these subcomplexes into CI and CI+CIII2, indicating that the subcomplexes are productive intermediates of assembly. The strong transient incorporation of new subunits into the 200-kDa subcomplex in a γ-CA mutant is consistent with this subcomplex being a key initiator of CI assembly in plants. This evidence alongside the pattern of coincident occurrence of genes encoding these particular proteins broadly in eukaryotes, except for opisthokonts, provides a framework for the evolutionary conservation of these accessory subunits and evidence of their function in ancestral CI assembly. PMID:23271729

Cough: are children really different to adults?

PubMed Central

Chang, Anne B

2005-01-01

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults. PMID:16270937

Nonrigid Autofocus Motion Correction for Coronary MR Angiography with a 3D Cones Trajectory

PubMed Central

Ingle, R. Reeve; Wu, Holden H.; Addy, Nii Okai; Cheng, Joseph Y.; Yang, Phillip C.; Hu, Bob S.; Nishimura, Dwight G.

2014-01-01

Purpose: To implement a nonrigid autofocus motion correction technique to improve respiratory motion correction of free-breathing whole-heart coronary magnetic resonance angiography (CMRA) acquisitions using an image-navigated 3D cones sequence. Methods: 2D image navigators acquired every heartbeat are used to measure superior-inferior, anterior-posterior, and right-left translation of the heart during a free-breathing CMRA scan using a 3D cones readout trajectory. Various tidal respiratory motion patterns are modeled by independently scaling the three measured displacement trajectories. These scaled motion trajectories are used for 3D translational compensation of the acquired data, and a bank of motion-compensated images is reconstructed. From this bank, a gradient entropy focusing metric is used to generate a nonrigid motion-corrected image on a pixel-by-pixel basis. The performance of the autofocus motion correction technique is compared with rigid-body translational correction and no correction in phantom, volunteer, and patient studies. Results: Nonrigid autofocus motion correction yields improved image quality compared to rigid-body-corrected images and uncorrected images. Quantitative vessel sharpness measurements indicate superiority of the proposed technique in 14 out of 15 coronary segments from three patient and two volunteer studies. Conclusion: The proposed technique corrects nonrigid motion artifacts in free-breathing 3D cones acquisitions, improving image quality compared to rigid-body motion correction. PMID:24006292

Shared developmental and evolutionary origins for neural basis of vocal–acoustic and pectoral–gestural signaling

PubMed Central

Bass, Andrew H.; Chagnaud, Boris P.

2012-01-01

Acoustic signaling behaviors are widespread among bony vertebrates, which include the majority of living fishes and tetrapods. Developmental studies in sound-producing fishes and tetrapods indicate that central pattern generating networks dedicated to vocalization originate from the same caudal hindbrain rhombomere (rh) 8-spinal compartment. Together, the evidence suggests that vocalization and its morphophysiological basis, including mechanisms of vocal–respiratory coupling that are widespread among tetrapods, are ancestral characters for bony vertebrates. Premotor-motor circuitry for pectoral appendages that function in locomotion and acoustic signaling develops in the same rh8-spinal compartment. Hence, vocal and pectoral phenotypes in fishes share both developmental origins and roles in acoustic communication. These findings lead to the proposal that the coupling of more highly derived vocal and pectoral mechanisms among tetrapods, including those adapted for nonvocal acoustic and gestural signaling, originated in fishes. Comparative studies further show that rh8 premotor populations have distinct neurophysiological properties coding for equally distinct behavioral attributes such as call duration. We conclude that neural network innovations in the spatiotemporal patterning of vocal and pectoral mechanisms of social communication, including forelimb gestural signaling, have their evolutionary origins in the caudal hindbrain of fishes. PMID:22723366

Gaps in capacity for respiratory care in developing countries. Nigeria as a case study.

PubMed

Obaseki, Daniel; Adeniyi, Bamidele; Kolawole, Tolulope; Onyedum, Cajetan; Erhabor, Gregory

2015-04-01

There are unmet needs for respiratory medical care in developing countries. We sought to evaluate the quality and capacity for respiratory care in low- and lower-middle-income countries, using Nigeria as a case study. We obtained details of the respiratory practice of consultants and senior residents (fellows) in respiratory medicine in Nigeria via a semistructured questionnaire administered to physician attendees at the 2013 National Congress of the Nigerian Thoracic Society. Out of 76 society-registered members, 48 attended the congress, 40 completed the questionnaire, and 35 provided complete data (73% adjusted response rate). Respondents provided information on the process and costs of respiratory medicine training and facility, equipment, and supply capacities at the institutions they represented. Approximately 83% reported working at a tertiary level (teaching) hospital; 91% reported capacity for sputum smear analysis for acid alcohol-fast bacilli, 37% for GeneXpert test cartridges, and 20% for BACTEC liquid sputum culture. Only 34% of respondents could perform full spirometry on patients, and none had the capacity for performing a methacholine challenge test or for measuring the diffusion capacity for carbon monoxide. We estimated the proportion of registered respiratory physicians to the national population at 1 per 2.3 million individuals. Thirteen states with an estimated combined population of 57.7 million offer no specialist respiratory services. Barriers to development of this capacity include the high cost of training. We conclude that substantial gaps exist in the capacity and quality of respiratory care in Nigeria, a pattern that probably mirrors most of sub-Saharan Africa and other countries of similar economic status. Health policy makers should address these gaps systematically.

Respiratory Protection Toolkit: Providing Guidance Without Changing Requirements-Can We Make an Impact?

PubMed

Bien, Elizabeth Ann; Gillespie, Gordon Lee; Betcher, Cynthia Ann; Thrasher, Terri L; Mingerink, Donna R

2016-12-01

International travel and infectious respiratory illnesses worldwide place health care workers (HCWs) at increasing risk of respiratory exposures. To ensure the highest quality safety initiatives, one health care system used a quality improvement model of Plan-Do-Study-Act and guidance from Occupational Safety and Health Administration's (OSHA) May 2015 Hospital Respiratory Protection Program (RPP) Toolkit to assess a current program. The toolkit aided in identification of opportunities for improvement within their well-designed RPP. One opportunity was requiring respirator use during aerosol-generating procedures for specific infectious illnesses. Observation data demonstrated opportunities to mitigate controllable risks including strap placement, user seal check, and reuse of disposable N95 filtering facepiece respirators. Subsequent interdisciplinary collaboration resulted in other ideas to decrease risks and increase protection from potentially infectious respiratory illnesses. The toolkit's comprehensive document to evaluate the program showed that while the OSHA standards have not changed, the addition of the toolkit can better protect HCWs. © 2016 The Author(s).

Respiratory distress in term neonates in low-resource settings.

PubMed

Sivanandan, Sindhu; Agarwal, Ramesh; Sethi, Amanpreet

2017-08-01

Most neonatal deaths worldwide occur in low- and middle-income countries (LMICs). Respiratory distress is an important cause of neonatal morbidity and mortality. The epidemiology of respiratory distress among term neonates who constitute the vast majority of births is under reported. The scarcely available data from LMICs suggest an incidence of 1.2% to 7.2% among term live births and greater morbidity compared to that in high-income countries. Pneumonia and meconium aspiration syndrome are the predominant causes among outborn neonates, but next only to transient tachypnea among inborn neonates. Community management of neonatal sepsis/pneumonia using simplified antibiotic regimens when referral is not feasible, implementation of non-invasive ventilation, and innovative low-cost technologies to deliver respiratory therapy are important advances that have taken place in these settings. There is an urgent need to generate data on respiratory morbidities among term neonates so that the limited resources in these settings can be allocated judiciously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occupational and environmental lung disease.

PubMed

Seaman, Danielle M; Meyer, Cristopher A; Kanne, Jeffrey P

2015-06-01

Occupational and environmental lung disease remains a major cause of respiratory impairment worldwide. Despite regulations, increasing rates of coal worker's pneumoconiosis and progressive massive fibrosis are being reported in the United States. Dust exposures are occurring in new industries, for instance, silica in hydraulic fracking. Nonoccupational environmental lung disease contributes to major respiratory disease, asthma, and COPD. Knowledge of the imaging patterns of occupational and environmental lung disease is critical in diagnosing patients with occult exposures and managing patients with suspected or known exposures. Copyright © 2015 Elsevier Inc. All rights reserved.

A Wearable Respiratory Biofeedback System Based on Generalized Body Sensor Network

PubMed Central

Liu, Guan-Zheng; Huang, Bang-Yu

2011-01-01

Abstract Wearable medical devices have enabled unobtrusive monitoring of vital signs and emerging biofeedback services in a pervasive manner. This article describes a wearable respiratory biofeedback system based on a generalized body sensor network (BSN) platform. The compact BSN platform was tailored for the strong requirements of overall system optimizations. A waist-worn biofeedback device was designed using the BSN. Extensive bench tests have shown that the generalized BSN worked as intended. In-situ experiments with 22 subjects indicated that the biofeedback device was discreet, easy to wear, and capable of offering wearable respiratory trainings. Pilot studies on wearable training patterns and resultant heart rate variability suggested that paced respirations at abdominal level and with identical inhaling/exhaling ratio were more appropriate for decreasing sympathetic arousal and increasing parasympathetic activities. PMID:21545293

Mortality patterns associated with the 1918 influenza pandemic in Mexico: evidence for a spring herald wave and lack of pre-existing immunity in older populations

PubMed Central

Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone; Miller, Mark A.; Acuna-Soto, Rodolfo

2010-01-01

Background While the mortality burden of the devastating 1918 influenza pandemic has been carefully quantified in the US, Japan, and European countries, little is known about the pandemic experience elsewhere. Here, we compiled extensive archival records to quantify the pandemic mortality patterns in two Mexican cities, Mexico City and Toluca. Methods We applied seasonal excess mortality models to age-specific respiratory mortality rates for 1915–1920 and quantified the reproduction number from daily data. Results We identified 3 pandemic waves in Mexico City in spring 1918, fall 1918, and winter 1920, characterized by unusual excess mortality in 25–44 years old. Toluca experienced 2-fold higher excess mortality rates than Mexico City, but did not have a substantial 3rd wave. All age groups including those over 65 years experienced excess mortality during 1918–20. Reproduction number estimates were below 2.5 assuming a 3-day generation interval. Conclusion Mexico experienced a herald pandemic wave with elevated young adult mortality in spring 1918, similar to the US and Europe. In contrast to the US and Europe, there was no mortality sparing in Mexican seniors, highlighting potential geographical differences in pre-existing immunity to the 1918 virus. We discuss the relevance of our findings to the 2009 pandemic mortality patterns. PMID:20594109