Respiratory Physiology Research Articles

Nasal breathing: a neglected factor in metabolic regulation?

Abstract Purpose Nasal breathing (NB) is a fundamental physiological process, and emerging research indicates its potential role in modulating resting metabolism, impacting energy expenditure and metabolic efficiency. This study investigates the impact of NB on resting metabolic rate (RMR), offering novel insights into metabolic regulation. Methods A prospective study was conducted on patients undergoing nasal surgery, with measurements taken before and 3 months after surgery. Metabolic rate assessments, anthropometric dimensions, and peak nasal inspiratory flow (PNIF) were recorded. Factors like age, sex, and health status were considered to control for confounding variables. Results A total of 83 patients were initially enrolled: 17 underwent septorhinoplasty (SRP), 61 septoplasty (ST) and 5 inferior turbinate reduction alone. 72 patients completed the follow-up. SRP patients exhibited significantly higher pre- and post-operative RMR compared to ST patients (p = 0.005), and this association was not observed when PNIF was included in the analysis (p > 0.05). Pre-operative and post-operative PNIF values significantly correlated with pre-operative and post-operative RMR (p = 0.049 and p = 0.005, respectively). Post-operative PNIF predicted post-operative RMR after confoundment adjustment in linear regression (β = – 0.043, p = 0.017). Importantly, total body weight increased after surgery (pre-op: 74 ± 14.6 kg versus post-op: 75.6 ± 15.5 kg, p < 0.001) due to an increment in muscle mass (pre-op: 52.3 ± 12 versus post-op: 55.5 ± 14, p < 0.01). Conclusion Preliminary analysis suggests a potential link between NB and RMR, emphasizing the overlooked role of nasal respiratory physiology in energy homeostasis. Surgery also elicited body composition alterations. Further research is needed to uncover the underlying mechanisms of this association. Understanding the impact of NB on RMR could underscore its significance in metabolic regulation, reinforcing the importance of nasal surgery on overall health. This study provides foundation for future investigations.

Play your way to an "A": helping students engage during the social isolation of remote learning.

With the increased attention focused on active learning, educators strive to find better and more innovative ways to engage students in the classroom. One of the hurtles that educators are presented with is that the classroom is no longer limited to a physical location but rather students and professor can meet via the internet, Before COVID-19, distance or remote learning was something that students, by and large, had the option of choosing in which whether to engage. Students had the option to take "online courses," whether those be synchronous remote learning or asynchronous online courses. Indeed, numerous studies have focused on investigating the efficacy of many different approaches to distance and online learning. Unfortunately, COVID 19 mandated a rapid transition to remote learning, and with this forced change has come what some students describe as "Zoom fatigue" (Wolf CR. Psychology Today, May 2020). Many students reported feeling exhausted, overwhelmed, and disengaged by the dramatic increase in mandated distance education required by the COVID pandemic. Video conferencing has become the "go-to" panacea for education during this time, and students are spending unprecedented amounts of time in front of a screen when normally they would be in a classroom. This heretofore singular and unique approach to education coupled with decreased peer-to-peer interaction has caused a problem with student engagement (Goodman BE, Barker MK, Cooke JE. Adv Physiol Educ 42: 417-423, 2018). Students' engagement and performance have decreased during COVID-19 because of forced online learning and lack of peer interaction. We hypothesize that creating a nongraded, fun, and relaxing physiology-focused "Trivia Night" will increase student engagement and performance on summative assessments. Using a master's level class progressing through the respiratory physiology module utilizing remote, synchronous lectures to deliver content, we introduced a voluntary Trivia Night review session with teams randomly assigned to increase interaction among peers and review respiratory physiology material.NEW & NOTEWORTHY This article presents the effectiveness of the use of the "pub Trivia Night" to facilitate learning, deconstruct misconceptions, and increase engagement during remote teaching due to the COVID-19 pandemic.

Teaching the distribution of pulmonary blood flow using a Starling resistor model and turbine flowmeters.

The distribution of pulmonary blood flow is uneven and can be described as a three-zone model, the West zones: zone 1 occurs whenever alveolar pressure exceeds arterial pressure; zone 2 when the arterial pressure is greater than alveolar but the alveolar pressure exceeds the venous pressure; and finally zone 3 when both arterial and venous pressures exceed alveolar pressure. Consequently, the blood flow is almost determined by the difference between the arterial and venous pressures in zone 3 and between arterial and alveolar pressures in zone 2 and ceases in zone 1. The understanding of this subject may be difficult to some medical students. Therefore, to improve the learning of this topic in our physiology course, we used a didactic model to demonstrate the core concept of flow down gradients and its application to pulmonary blood flow. We modeled a Starling resistor by placing a collapsible tube inside a hermetic chamber of variable pressure. Transparent turbine flowmeters were connected to the upstream and downstream extremities of the Starling resistor, and we generated a constant airflow with a brushless motor. By maintaining the input (arterial) pressure constant and varying the chamber (alveolar) pressure, we could simulate the three zones and demonstrate the resulting flow through the turbines. In conclusion, our demonstration using a Starling resistor model combined with visible turbine flowmeters can be used to facilitate comprehension of important concepts in physiology involving flow down gradients, such as pulmonary blood flow.NEW & NOTEWORTHY The understanding of respiratory physiology is a challenge to medical students. To improve the learning of pulmonary blood flow distribution through lung vessels in our physiology course, we modeled a Starling resistor model combined with visible turbine flowmeters. Our model can significantly improve the core concept of flow down gradients teaching and its application to West zones.

Breathing modulates network activity in frontal brain regions during anxiety.

Anxiety elicits various physiological responses, including changes in respiratory rate and neuronal activity within specific brain regions such as the medial prefrontal cortex (mPFC). Previous research suggests that the olfactory bulb (OB) modulates the mPFC through respiration-coupled neuronal oscillations (RCOs), which have been linked to fear-related freezing behavior. Nevertheless, the impact of breathing on frontal brain networks during other negative emotional responses, such as anxiety-related states characterized by higher breathing rates, remains unclear. To address this, we subjected rats to the elevated plus maze (EPM) paradigm while simultaneously recording respiration and local field potentials in the OB and mPFC. Our findings demonstrate distinct respiratory patterns during EPM exploration: slower breathing frequencies prevailed in the closed arms, whereas faster frequencies were observed in the open arms, independent of locomotor activity, indicating that anxiety-like states are associated with increased respiratory rates. Additionally, we identified RCOs at different frequencies, mirroring the bimodal distribution of respiratory frequencies. RCOs exhibited higher power during open arm exploration, when they showed greater coherence with breathing at faster frequencies. Furthermore, we confirmed that nasal respiration drives RCOs in frontal brain regions, and found a stronger effect during faster breathing. Interestingly, we observed that the frequency of prefrontal gamma oscillations modulated by respiration increased with breathing frequency. Overall, our study provides evidence for a significant influence of breathing on prefrontal cortex networks during anxious states, shedding light on the complex interplay between respiratory physiology and emotional processing.Significance Statement Understanding how breathing influences brain activity during anxious states could pave the way for novel therapeutic interventions targeting respiratory control to alleviate anxiety symptoms. Our study uncovers a crucial link between respiratory patterns and anxiety-related neural activity in the brain. By investigating the interplay between breathing, neuronal oscillations, and emotional states, we reveal that anxiety induces distinct respiratory patterns, with higher breathing rates correlating with anxious behavior. Importantly, we demonstrate that respiration drives oscillatory activity in the prefrontal cortex, and this effect is potentiated during the fast breathing associated with anxiety. Furthermore, faster breathing modulates the emergence of faster prefrontal gamma oscillations. This discovery sheds new light on the intricate relationship between respiratory physiology and emotional processing.

Modulation of the Respiratory Epithelium Physiology by Flavonoids-Insights from 16HBEσcell Model.

Extensive evidence indicates that the compromise of airway epithelial barrier function is closely linked to the development of various diseases, posing a significant concern for global mortality and morbidity. Flavonoids, natural bioactive compounds, renowned for their antioxidant and anti-inflammatory properties, have been used for centuries to prevent and treat numerous ailments. Lately, a growing body of evidence suggests that flavonoids can enhance the integrity of the airway epithelial barrier. The objective of this study was to investigate the impact of selected flavonoids representing different subclasses, such as kaempferol (flavonol), luteolin (flavone), and naringenin (flavanone), on transepithelial electrical resistance (TEER), ionic currents, cells migration, and proliferation of a human bronchial epithelial cell line (16HBE14σ). To investigate the effect of selected flavonoids, MTT assay, trypan blue staining, and wound healing were assessed. Additionally, transepithelial resistance and Ussing chamber measurements were applied to investigate the impact of the flavonoids on the electrical properties of the epithelial barrier. This study showed that kaempferol, luteolin, and naringenin at micromolar concentrations were not cytotoxic to 16HBE14σ cells. Indeed, in MTT tests, a statistically significant change in cell metabolic activity for luteolin and naringenin was observed. However, our experiments showed that naringenin did not affect the proliferation of 16HBE14σ cells, while the effect of kaempferol and luteolin was inhibitory. Moreover, transepithelial electrical resistance measurements have shown that all of the flavonoids used in this study improved the epithelial integrity with the slightest effect of kaempferol and the significant impact of naringenin and luteolin. Finally, our observations suggest that luteolin increases the Cl- transport through cystic fibrosis transmembrane conductance regulator (CFTR) channel. Our findings reveal that flavonoids representing different subclasses exert distinct effects in the employed cellular model despite their similar chemical structures. In summary, our study sheds new light on the diverse effects of selected flavonoids on airway epithelial barrier function, underscoring the importance of further exploration into their potential therapeutic applications in respiratory health.

A randomized control trial evaluating the advice of a physiological-model/digital twin-based decision support system on mechanical ventilation in patients with acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is highly heterogeneous, both in its clinical presentation and in the patient's physiological responses to changes in mechanical ventilator settings, such as PEEP. This study investigates the clinical efficacy of a physiological model-based ventilatory decision support system (DSS) to personalize ventilator therapy in ARDS patients. This international, multicenter, randomized, open-label study enrolled patients with ARDS during the COVID-19 pandemic. Patients were randomized to either receive active advice from the DSS (intervention) or standard care without DSS advice (control). The primary outcome was to detect a reduction in average driving pressure between groups. Secondary outcomes included several clinically relevant measures of respiratory physiology, ventilator-free days, time from control mode to support mode, number of changes in ventilator settings per day, percentage of time in control and support mode ventilation, ventilation- and device-related adverse events, and the number of times the advice was followed. A total of 95 patients were randomized in this study. The DSS showed no significant effect on average driving pressure between groups. However, patients in the intervention arm had a statistically improved oxygenation index when in support mode ventilation (-1.41, 95% CI: -2.76, -0.08; p = 0.0370). Additionally, the ventilatory ratio significantly improved in the intervention arm for patients in control mode ventilation (-0.63, 95% CI: -1.08, -0.17, p = 0.0068). The application of the DSS led to a significantly increased number of ventilator changes for pressure settings and respiratory frequency. The use of a physiological model-based decision support system for providing advice on mechanical ventilation in patients with COVID-19 and non-COVID-19 ARDS showed no significant difference in driving pressure as a primary outcome measure. However, the application of approximately 60% of the DSS advice led to improvements in the patient's physiological state. clinicaltrials.gov, NCT04115709.

Impact of COVID-19 on Diaphragmatic Function: Understanding Multiorgan Involvement and Long-Term Consequences.

The COVID-19 pandemic has brought significant attention to the respiratory system, with much focus on lung-related disorders. However, the diaphragm, a crucial component of respiratory physiology, has not been adequately studied, especially in the context of long COVID. This review explores the multipotential role of the diaphragm in both respiratory health and disease, emphasizing its involvement in long-term complications following SARS-CoV-2 infection. The diaphragm's fundamental role in respiratory physiology and its impact on balance and posture control, breathing patterns, and autonomic nervous system regulation are discussed. This review examines complications arising from COVID-19, highlighting the diaphragm's involvement in neurological, musculoskeletal, and inflammatory responses. Particular attention is given to the neuroinvasive impact of SARS-CoV-2, the inflammatory response, and the direct viral effects on the diaphragm. The diaphragm's role in long COVID is explored, with a focus on specific symptoms such as voice disorders, pelvic floor dysfunction, and sleep disturbances. Diagnostic challenges, current methods for assessing diaphragmatic dysfunction, and the complexities of differentiating it from other conditions are also explored. This article is the first to comprehensively address diaphragmatic dysfunction resulting from COVID-19 and long COVID across various physiological and pathological aspects, offering a new perspective on its diagnosis and treatment within a multisystem context.

Influence of Kunjal Kriya on Respiratory Physiology - A Comprehensive Review

Influence of Kunjal Kriya on Respiratory Physiology - A Comprehensive Review

Influence of catheter thickness on respiratory physiology during less invasive surfactant administration in extremely preterm infants.

Delivering surfactant via thin catheters (minimal-invasive surfactant therapy (MIST); less invasive surfactant administration (LISA)) has become a common procedure. However, the effect of tracheal obstruction caused by catheters of different sizes on tracheal resistance in extremely low gestational age newborns (ELGANs) is unknown. To investigate the effect of catheters size 3.5, 5 and 6 French on airway resistance in ELGANs of 23-28 weeks gestational age during LISA, we performed calculations based on Hagen-Poiseuille's law and compared these with a clinically and physically more accurate method: computational fluid dynamics (CFD) simulations of respiratory airflow, performed in 3D virtual airway models derived from MRI. The presence of the above catheters decreased the cross-sectional area of the infants' tracheal entrance (the cricoid ring) by 13-53%. Hagen-Poiseuille's law predicted an increase in resistance by 1.5-4.5 times and 1.3-2.6 times in ELGANs born at 23 and 28 weeks, respectively. However, CFD simulations demonstrated an even higher increase in resistance of 3.4-85.1 and 1.1-3.5 times, respectively. The higher calculated resistances were due to the extremely narrow remaining lumen at the glottis and cricoid with the catheter inserted, resulting in a stronger glottal jet and turbulent airflow, which was not predicted by Hagen-Poiseuille. Catheter thickness can greatly increase tracheal resistance during LISA-procedures in ELGANs. Based on these models, it is recommended to use the thinnest catheter possible during LISA in ELGANs to avoid unnecessary increases in airway resistance in infants already experiencing dyspnea due to respiratory distress syndrome.

Optimisation de la prise en charge par l’activité physique des patients atteints d’un syndrome d’Ehlers-Danlos hypermobile

IntroductionHypermobile Ehlers-Danlos syndrome (hEDS) is a hereditary connective tissue disorder with a wide phenotypic variability. The aim of this thesis was to optimize the management by physical activity of hEDS patients. MethodsTo meet this objective, five studies were conducted. The first study (questionnaire with Delphi method) showed that pain, fatigue and sleep disorders, as well as musculoskeletal disorders, were among the most important symptoms to assess according to patients. ResultsTwo studies (retrospective and prospective) were conducted on the effects of a rehabilitation program, demonstrating the benefits of this form of care in many health areas. Finally, two studies on respiratory physiology showed ventilatory mechanical constraints during exercise and altered perception of lung volume and erratic ventilation when performing a cognitive task.

Physiological effects and safety of bed verticalization in patients with acute respiratory distress syndrome

BackgroundTrunk inclination in patients with Acute Respiratory Distress Syndrome (ARDS) in the supine position has gained scientific interest due to its effects on respiratory physiology, including mechanics, oxygenation, ventilation distribution, and efficiency. Changing from flat supine to semi-recumbent increases driving pressure due to decreased respiratory system compliance. Positional adjustments also deteriorate ventilatory efficiency for CO2 removal, particularly in COVID-19-associated ARDS (C-ARDS), indicating likely lung parenchyma overdistension. Tilting the trunk reduces chest wall compliance and, to a lesser extent, lung compliance and transpulmonary driving pressure, with significant hemodynamic and gas exchange implications.MethodsA prospective, pilot physiological study was conducted on early ARDS patients in two ICUs at CHU Clermont-Ferrand, France. The protocol involved 30-min step gradual verticalization from a 30° semi-seated position (baseline) to different levels of inclination (0°, 30°, 60°, and 90°), before returning to the baseline position. Measurements included tidal volume, positive end-expiratory pressure (PEEP), esophageal pressures, and pulmonary artery catheter data. The primary endpoint was the variation in transpulmonary driving pressure through the verticalization procedure.ResultsFrom May 2020 through January 2021, 30 patients were included. Transpulmonary driving pressure increased slightly from baseline (median and interquartile range [IQR], 9 [5–11] cmH2O) to the 90° position (10 [7–14] cmH2O; P < 10–2 for the overall effect of position in mixed model). End-expiratory lung volume increased with verticalization, in parallel to decreases in alveolar strain and increased arterial oxygenation. Verticalization was associated with decreased cardiac output and stroke volume, and increased norepinephrine doses and serum lactate levels, prompting interruption of the procedure in two patients. There were no other adverse events such as falls or equipment accidental removals.ConclusionsVerticalization to 90° is feasible in ARDS patients, improving EELV and oxygenation up to 30°, likely due to alveolar recruitment and blood flow redistribution. However, there is a risk of overdistension and hemodynamic instability beyond 30°, necessitating individualized bed angles based on clinical situations.Trial registration ClinicalTrials.gov registration number NCT04371016, April 24, 2020.

Physiological and clinical effects of trunk inclination adjustment in patients with respiratory failure: a scoping review and narrative synthesis

BackgroundAdjusting trunk inclination from a semi-recumbent position to a supine-flat position or vice versa in patients with respiratory failure significantly affects numerous aspects of respiratory physiology including respiratory mechanics, oxygenation, end-expiratory lung volume, and ventilatory efficiency. Despite these observed effects, the current clinical evidence regarding this positioning manoeuvre is limited. This study undertakes a scoping review of patients with respiratory failure undergoing mechanical ventilation to assess the effect of trunk inclination on physiological lung parameters.MethodsThe PubMed, Cochrane, and Scopus databases were systematically searched from 2003 to 2023. Interventions: Changes in trunk inclination. Measurements: Four domains were evaluated in this study: 1) respiratory mechanics, 2) ventilation distribution, 3) oxygenation, and 4) ventilatory efficiency.ResultsAfter searching the three databases and removing duplicates, 220 studies were screened. Of these, 37 were assessed in detail, and 13 were included in the final analysis, comprising 274 patients. All selected studies were experimental, and assessed respiratory mechanics, ventilation distribution, oxygenation, and ventilatory efficiency, primarily within 60 min post postural change.ConclusionIn patients with acute respiratory failure, transitioning from a supine to a semi-recumbent position leads to decreased respiratory system compliance and increased airway driving pressure. Additionally, C-ARDS patients experienced an improvement in ventilatory efficiency, which resulted in lower PaCO2 levels. Improvements in oxygenation were observed in a few patients and only in those who exhibited an increase in EELV upon moving to a semi-recumbent position. Therefore, the trunk inclination angle must be accurately reported in patients with respiratory failure under mechanical ventilation.

Dual role of transient receptor potential ankyrin 1 in respiratory and gastrointestinal physiology: From molecular mechanisms to therapeutic targets.

The transient receptor potential ankyrin 1 (TRPA1) channel plays a pivotal role in the respiratory and gastrointestinal tracts. Within the respiratory system, TRPA1 exhibits diverse distribution patterns across key cell types, including epithelial cells, sensory nerves, and immune cells. Its activation serves as a frontline sensor for inhaled irritants, triggering immediate protective responses, and influencing airway integrity. Furthermore, TRPA1 has been implicated in airway tissue injury, inflammation, and the transition of fibroblasts, thereby posing challenges in conditions, such as severe asthma and fibrosis. In sensory nerves, TRPA1 contributes to nociception, the cough reflex, and bronchoconstriction, highlighting its role in both immediate defense mechanisms and long-term respiratory reflex arcs. In immune cells, TRPA1 may modulate the release of pro-inflammatory mediators, shaping the overall inflammatory landscape. In the gastrointestinal tract, the dynamic expression of TRPA1 in enteric neurons, epithelial cells, and immune cells underscores its multifaceted involvement. It plays a crucial role in gut motility, visceral pain perception, and mucosal defense mechanisms. Dysregulation of TRPA1 in both tracts is associated with various disorders such as asthma, Chronic Obstructive Pulmonary Disease, Irritable Bowel Syndrome, and Inflammatory Bowel Disease. This review emphasizes the potential of TRPA1 as a therapeutic target and discusses the efficacy of TRPA1 antagonists in preclinical studies and their promise for addressing respiratory and gastrointestinal conditions. Understanding the intricate interactions and cross-talk of TRPA1 across different cell types provides insight into its versatile role in maintaining homeostasis in vital physiological systems, offering a foundation for targeted therapeutic interventions.

CLASSIFICATION OF TANAFFUS (RESPIRATION) WITH SPECIAL REFERENCE TO UNANI MEDICINE: A REVIEW

Breathing or respiration has been essential in human life since ancient times. Philosophers and physicians of ancient times such as Hippocrates, Galen, and others had already written about breathing in literature. These antiquated viewpoints established the foundation for contemporary respiratory physiology and medicine. The Hippocratic literature established the importance of breath in maintaining the body's humour balance, whereas Galen elaborates on the anatomical and functional elements of respiration. Literature related to respiration is surveyed from various Unani classical books and their translations, commentaries, previous dissertations, journals, proceedings, etc. Hippocrates and Ibne Sina mentioned ten and seventeen types of respiration respectively. Ibne Sina also explained five special types of respirations. This research paper aims to explore and analyse the understanding and significance of respiration in the Unani system of medicine. And also provides a comprehensive overview of how ancient philosophers understood respiration.

Leveraging technology to improve access to medical education in anatomy and physiology in resource-limited settings: A mixed methods study.

This study assesses the acceptability, appropriateness, feasibility, and efficacy of a novel asynchronous video-based intervention for teaching respiratory physiology and anatomy to medical students in resource-limited settings. A series of short video lectures on pleural anatomy, pulmonary physiology, and pathophysiology was created using Lightboard and screen capture technology. These were uploaded to YouTube and Google Drive and made available to 1st-3rd year medical students at two Latin American universities for 1 week. Employing a parallel-convergent mixed methods design, we conducted surveys, focus groups, interviews, and pre/post testing for qualitative and quantitative data. Thematic Analysis was used to analyze qualitative data and McNemar's test for quantitative analysis. Seventy-six students participated. The videos' short format, interactivity, and Lightboard style were highly valued for their flexibility, time efficiency, and educational impact. Students recognized their clinical relevance and trusted their content, suggesting potential applicability in similar settings. Despite infrastructure and connectivity challenges, the use of flexible streaming and downloadable options facilitated learning. Survey results indicated high levels of feasibility (99%), appropriateness (95%), and acceptability (95%), with significant knowledge gains observed (37% correct pre-test answers vs. 56% post-test, p < 0.0001). Our findings demonstrate high acceptability, appropriateness, feasibility, and efficacy of a targeted asynchronous education centered on short-format videos in resource-limited settings, enabling robust learning despite local barriers. Flexible access is key for overcoming localized barriers. Taking an adaptive, learner-centered approach to content creation and delivery to address constraints was pivotal to success. Our modular videos could serve as versatile models for flexible education in resource-constrained settings.

The Cardio-Respiratory Mechanisms Involved in the Diving Response Adaptation and Breath-Hold Training Effects in Freedivers

This review aims to explore the cardiovascular and respiratory mechanisms involved in the training effects of the diving response adaptation and to determine the adaptive changes during apnoea and breath-hold training in breath-hold divers. A sounder theoretical knowledge of these critical aspects is necessary to be able to understand the oxygen-conserving mechanism of the diving response, and the apnoea-induced cardiorespiratory adjustments involved in enriching the science of respiratory physiology and the development of breath-hold training and ability. These insights may contribute to understanding the pathophysiology of respiratory abnormalities and dysfunctional breathing in humans. Furthermore, it may facilitate the development of efficacious interventions to increase breath-holding ability, and sports performance, as well as assist with the management and treatment of various physiological and psychological conditions. This review will be presented in four separate sections. Section one will describe the diving response and its physiology. Section two will explore the cardio-respiratory mechanisms of the diving response. Section three will discuss the adaptive changes associated with breath-hold training and/or apnoea training, as well as the associated cardio-respiratory adaptions. Section four will explore the clinical applications and implications of the diving response.

Genetic identification of medullary neurons underlying congenital hypoventilation.

Mutations in the transcription factors encoded by PHOX2B or LBX1 correlate with congenital central hypoventilation disorders. These conditions are typically characterized by pronounced hypoventilation, central apnea, and diminished chemoreflexes, particularly to abnormally high levels of arterial PCO2. The dysfunctional neurons causing these respiratory disorders are largely unknown. Here, we show that distinct, and previously undescribed, sets of medullary neurons coexpressing both transcription factors (dB2 neurons) account for specific respiratory functions and phenotypes seen in congenital hypoventilation. By combining intersectional chemogenetics, intersectional labeling, lineage tracing, and conditional mutagenesis, we uncovered subgroups of dB2 neurons with key functions in (i) respiratory tidal volumes, (ii) the hypercarbic reflex, (iii) neonatal respiratory stability, and (iv) neonatal survival. These data provide functional evidence for the critical role of distinct medullary dB2 neurons in neonatal respiratory physiology. In summary, our work identifies distinct subgroups of dB2 neurons regulating breathing homeostasis, dysfunction of which causes respiratory phenotypes associated with congenital hypoventilation.

Understanding of Pranavaha Sroto Moola in the purview of modern physiology

Introduction: Pranavaha Srotas are the first Srotas to be enlisted in Charaka Samhita. These channels carry Prana all over the body to all bodily tissues. Pranavaha Srotas has its Moola in Hridaya and Mahasrotas according to Charaka Samhita while Sushuruta Samhita states that Hridaya and Rasavahini Dhamanis as Moola. Moola of Pranavaha Srotas not only denotes the anatomical aspects but also represents the functional entities. Methods: A comprehensive literature review was done on Pranavaha Srotas in Ayurveda and the physiology of respiration according to contemporary science through searching classical texts, textbooks, and online articles from peer-reviewed journals to narrate the Anatomical, Functional/physiological aspects, and Therapeutic aspects of Pranavaha Sroto Moola. Results: Pranavaha Srotas can be considered as a functional unit that consists of the heart, brain, and alimentary canal. Respiratory physiology is directly linked to the circulatory, gastro gastrointestinal systems for the exchange of gases, absorption, transportation, excretion, monitoring, and control of all activities. Conclusion: Pranavaha Srotas is the basic system that works in harmony with all the physiological attributes of the body like circulatory, alimentary, and nervous systems.

Exploring the Complexity of the Human Respiratory Virome through an In Silico Analysis of Shotgun Metagenomic Data Retrieved from Public Repositories.

Respiratory viruses significantly impact global morbidity and mortality, causing more disease in humans than any other infectious agent. Beyond pathogens, various viruses and bacteria colonize the respiratory tract without causing disease, potentially influencing respiratory diseases' pathogenesis. Nevertheless, our understanding of respiratory microbiota is limited by technical constraints, predominantly focusing on bacteria and neglecting crucial populations like viruses. Despite recent efforts to improve our understanding of viral diversity in the human body, our knowledge of viral diversity associated with the human respiratory tract remains limited. Following a comprehensive search in bibliographic and sequencing data repositories using keyword terms, we retrieved shotgun metagenomic data from public repositories (n = 85). After manual curation, sequencing data files from 43 studies were analyzed using EVEREST (pipEline for Viral assEmbly and chaRactEriSaTion). Complete and high-quality contigs were further assessed for genomic and taxonomic characterization. Viral contigs were obtained from 194 out of the 868 FASTQ files processed through EVEREST. Of the 1842 contigs that were quality assessed, 8% (n = 146) were classified as complete/high-quality genomes. Most of the identified viral contigs were taxonomically classified as bacteriophages, with taxonomic resolution ranging from the superkingdom level down to the species level. Captured contigs were spread across 25 putative families and varied between RNA and DNA viruses, including previously uncharacterized viral genomes. Of note, airway samples also contained virus(es) characteristic of the human gastrointestinal tract, which have not been previously described as part of the lung virome. Additionally, by performing a meta-analysis of the integrated datasets, ecological trends within viral populations linked to human disease states and their biogeographical distribution along the respiratory tract were observed. By leveraging publicly available repositories of shotgun metagenomic data, the present study provides new insights into viral genomes associated with specimens from the human respiratory tract across different disease spectra. Further studies are required to validate our findings and evaluate the potential impact of these viral communities on respiratory tract physiology.

Physiological Characteristics of Surgical Patients With Obesity in Response to the 6-Min Walk Test

ABSTRACT Background: Overall health and fitness contribute to surgical experience and recovery. The aim of this study was to describe an array of physiological characteristics in a presurgical patient cohort with obesity as a function of their sustained walking speed. Methods: We performed a prospective single-center cohort study in Wollongong Hospital, Australia from 2016 to 2018. Patients (N = 293) with severe obesity completed a 6-min walk test and were classified as either slow or fast walkers according to the cut point of 0.9 m·s−1 (2 mph). These groups were compared for anthropometry, comorbidities, respiratory and cardiovascular physiology, blood biomarkers, patient-centered outcomes, and perception of effort. Results: Slow walkers (n = 115; age 65 [63 to 67] years; mean [95% confidence interval]) and fast walkers (n = 178; age 54 [52 to 56]; P &amp;lt; 0.05) were not different in body weight but were different for body mass index (slow 43.2 [42.0 to 44.4] versus fast 41.1 [40.5 to 41.8]; P &amp;lt; 0.05). Cardiovascular disease and renal disease were more prevalent in slow walkers. Respiratory physiology reflective of restrictive lung disease (force vial capacity [L] slow 2.61 [2.45 to 2.77] versus fast 3.34 [3.19 to 3.47]; P &amp;lt; 0.05) was more common in slow walkers, who also reported higher dyspnea ratings. Resting cardiovascular characteristics were not different, although N-terminal pro-B-type natriuretic peptide levels were higher in the slow group (P &amp;lt; 0.05). Quality of recovery at postoperative day 30 was higher in the fast walking group. Conclusion: In this Australian cohort, patients with obesity undergoing nonbariatric surgery differed in their physiological profiles according to walking speed. This study supports the need to appreciate the physical fitness of patients beyond simplified body weight and classification of obesity in the perioperative period.