Journal articles: 'Respiratory system conductance' – Grafiati (2024)

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We have developed a technique for measuring lung function in conscious guinea pigs using a whole body plethysmograph. Because guinea pigs breathe through the nose, a technique was also developed to measure nasal and lower respiratory system conductance simultaneously in anesthetized animals. The upper and the lower airways could be challenged separately and studied in a manner similar to the conditions in the plethysmograph. Aerosols of histamine, carbachol, or ovalbumin delivered to the nose in sensitized animals had no effect on nasal conductance, even in doses 100 times higher than that required to reduce lower respiratory system conductance. However, intravenous histamine increased nasal conductance. Thus, although nasal resistance constitutes the majority of the total respiratory system resistance measured in the plethysmograph, nasal resistance is unaffected by the aerosol drugs studied. We therefore consider changes in resistance measured in the plethysmograph to originate at or below the larynx. The plethysmographic technique described here is a reliable, reproducible, and rapid technique that enables repeated measurement in animals and minimizes animal trauma.

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An unwanted side effect of isoflurane anesthesia is suppression of breathing. Despite this clinical significance, effects of isoflurane on cellular and molecular elements of respiratory control are not well understood. Here, we show that isoflurane inhibits heteromeric Kir4.1/5.1 channels in a mammalian expression system, and a Kir4.1/5.1-like conductance in astrocytes in a brainstem respiratory center. These results identify astrocyte Kir4.1/5.1 channels as novel targets of isoflurane and potential substrates for altered respiratory control during isoflurane anesthesia.

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Numerous studies have reported on cancers among Mayak Production Association (PA) nuclear workers. Other studies have reported on serious deterministic effects of large radiation doses for the same population. This study relates to deterministic effects (respiratory system dysfunction) in Mayak workers after relatively small chronic radiation doses (alpha plus gamma). Because cigarette smoke is a confounding factor, we also account for smoking effects. Here we present a new empirical mathematical model that was introduced for simultaneous assessment of radiation and cigarette-smoking-related damage to the respiratory system. The model incorporates absolute thresholds for smoking- and radiation-induced respiratory system dysfunction. As the alpha radiation dose to the lung increased from 0 to 4.36 Gy, respiratory function indices studied decreased, although remaining in the normal range. The data were consistent with the view that alpha radiation doses to the lung above a relatively small threshold (0.15 to 0.39 Gy) cause some respiratory system dysfunction. Respiratory function indices were not found to be influenced by total-body gamma radiation doses in the range 0–3.8 Gy when delivered at low rates over years. However, significant decreases in airway conductance were found to be associated with cigarette smoking. Whether the indicated cigarette smoking and alpha radiation associated dysfunction is debilitating is unclear.

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The aim of investigation: to ground the use of a new combined mud medication «Tone plus» in pulmonologic practice. The investigation has been made on 53 patients with chronic bronchitis (CB) and bronchial asthma (BA). Inhalations with «Tone plus» consisting of three components — saline carrier, herb and peloids extracts — have been the main medication. Efficiency of the therapy has been assessed grounding on the movement of local respiratory tract protection indices by the method of examination of nasal tunica mucosa smear and nasal secretion, on the airway conductance by spirograph, inflammation activity by blood clinico-biochemical analysis and on organism adaptation system state by L.A. Garkavy’s method. In atmiatrics there has been registered local and system anti-inflammatory effect, airway conductance improvement and improvement of upper airway cover epithelium state, increase of functional activity of respiratory tract tunica micosa cells. Inhalations of a new combined mud medication «Tone plus» are a promising method of non-pharmacotherapeutic atmiatrics of patients with CB and BA.

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Although respiratory sinus arrhythmia and blood pressure variability have been investigated extensively, there have been far fewer studies of the respiratory modulation of peripheral blood flow in humans. Existing studies have been based primarily on noninvasive measurements using digit photoplethysmography and laser-Doppler flowmetry. The cumulative knowledge derived from these studies suggests that respiration can contribute to fluctuations in peripheral blood flow and volume through a combination of mechanical, hemodynamic, and neural mechanisms. However, the most convincing evidence suggests that the sympathetic nervous system plays the predominant role under normal, resting conditions. This mini-review provides a consolidation and interpretation of the key findings reported in this topical area. Given the need to extract dynamic information from noninvasive measurements under largely “closed-loop” conditions, we propose that the application of analytical tools based on systems theory and mathematical modeling can be of great utility in future studies. In particular, we present an example of how the transfer relation linking respiration to peripheral vascular conductance can be derived using measurements recorded during spontaneous breathing, spontaneous sighs, and ventilator-induced sighs.

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Chronic kidney disease (CKD) leads to increased skeletal muscle fatigue, weakness, and atrophy. Previous work has implicated mitochondria within the skeletal muscle as a mediator of muscle dysfunction in CKD; however, the mechanisms underlying mitochondrial dysfunction in CKD are not entirely known. The purpose of this study was to define the impact of uremic metabolites on mitochondrial energetics. Skeletal muscle mitochondria were isolated from C57BL/6N mice and exposed to vehicle (DMSO) or varying concentrations of uremic metabolites: indoxyl sulfate, indole-3-acetic-acid, l-kynurenine, and kynurenic acid. A comprehensive mitochondrial phenotyping platform that included assessments of mitochondrial oxidative phosphorylation (OXPHOS) conductance and respiratory capacity, hydrogen peroxide production ( JH2O2), matrix dehydrogenase activity, electron transport system enzyme activity, and ATP synthase activity was employed. Uremic metabolite exposure resulted in a ~25–40% decrease in OXPHOS conductance across multiple substrate conditions ( P < 0.05, n = 5–6/condition), as well as decreased ADP-stimulated and uncoupled respiratory capacity. ATP synthase activity was not impacted by uremic metabolites; however, a screen of matrix dehydrogenases indicated that malate and glutamate dehydrogenases were impaired by some, but not all, uremic metabolites. Assessments of electron transport system enzymes indicated that uremic metabolites significantly impair complex III and IV. Uremic metabolites resulted in increased JH2O2 under glutamate/malate, pyruvate/malate, and succinate conditions across multiple levels of energy demand (all P < 0.05, n = 4/group). Disruption of mitochondrial OXPHOS was confirmed by decreased respiratory capacity and elevated superoxide production in cultured myotubes. These findings provide direct evidence that uremic metabolites negatively impact skeletal muscle mitochondrial energetics, resulting in decreased energy transfer, impaired complex III and IV enzyme activity, and elevated oxidant production.

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1. Labeled premotor respiratory neurons from neonatal rats in culture were used to study the effects of (+/-)baclofen, a selective gamma-aminobutyric acid (GABA)b receptor agonist known to inhibit rhythmic breathing movements in mammals. Bath application of (+/-)baclofen-activated outward currents in cell-attached patches, suggesting that a second messenger system linked the (+/-)baclofen-activated conductance (GBac) to the GABAb receptor. 2.GBac channels exhibited outward rectification and were insensitive to blockade by Ba2+ and Cs+. The single-channel conductance was 100 pS in symmetrical K+ solutions and decreased as [K+]o was reduced. The reversal potential for the GBac channel shifted 45 mV/decade when [K+]o was changed indicating that it was predominantly selective for K+ ions. These properties were similar to those of the S-channel in Aplysia sensory neurons. 3. The properties of GBac channels were distinct from those associated with the GABAb mediated slow inhibitory postsynaptic potential (IPSP), indicating that GABAb receptors can be associated with more than one type of K+ channel. We propose that GBac channels modulate the repetitive firing activity of premotor respiratory neurons and may also participate in presynaptic inhibition.

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To explore whether asthma and obesity share overlapping pathogenic features, we examined the impact of each alone, and in combination, on multiple aspects of lung function. We reasoned that if they influenced the lungs through similar mechanisms, the individual physiological manifestations in the comorbid state should interact in a complex fashion. If not, then the abnormalities should simply add. We measured specific conductance, spirometry, lung volumes, and airway responsiveness to adrenergic and cholinergic agonists in 52 normal, 53 asthmatic, 52 obese, and 53 asthmatic and obese patients using standard techniques. Six-minute walks were performed in subsets from each group. Asthma significantly lowered specific conductance and the spirometric variables while increasing airway reactivity and residual volume. Obesity also reduced the spirometric variables as well as total lung capacity and functional residual capacity. Residual volume, specific conductance, and airway responsivity were unaltered. With comorbidity, the disease-specific derangements added algebraically. Features that existed in isolation appeared unchanged in the combination, whereas shared ones either added or subtracted depending on the individual directional changes. Synergistic interactions were not observed. Body mass index weakly correlated with spirometry and lung volumes in asthma, but not with specific conductance or bronchial reactivity. Exercise performance did not aid in differentiation. Our findings indicate asthma and obesity appear to influence the respiratory system through different processes.

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Background Previous work performed by our group demonstrated that intermittent reductions in bispectral index (BIS) values were found during neurofeedback following mindfulness instructions. Hypnosis was induced to enhance reductions in BIS values. Objective This study aims to assess physiologic relaxation and explore its associations with BIS values using autonomic monitoring. Methods Each session consisted of reading a 4-minute baseline neutral script and playing an 18-minute hypnosis tape to 3 researchers involved in the BIS neurofeedback study. In addition to BIS monitoring, autonomic monitoring was performed, and this included measures of electromyography (EMG), skin temperature, skin conductance, respiratory rate, expired carbon dioxide, and heart rate variability. The resulting data were analyzed using two-tailed t tests, correlation analyses, and multivariate linear regression analyses. Results We found that hypnosis was associated with reductions in BIS (P<.001), EMG (P<.001), respiratory rate (P<.001), skin conductance (P=.006), and very low frequency power (P=.04); it was also associated with increases in expired carbon dioxide (P<.001), skin temperature (P=.04), high frequency power (P<.001), and successive heart interbeat interval difference (P=.04) values. Decreased BIS values were associated with reduced EMG measures (R=0.76; P<.001), respiratory rate (R=0.35; P=.004), skin conductance (R=0.57; P<.001), and low frequency power (R=0.32; P=.01) and with increased high frequency power (R=−0.53; P<.001), successive heart interbeat interval difference (R=−0.32; P=.009), and heart interbeat interval SD (R=−0.26; P=.04) values. Conclusions Hypnosis appeared to induce mental and physical relaxation, enhance parasympathetic neural activation, and attenuate sympathetic nervous system activity, changes that were associated with BIS values. Findings from this preliminary formative evaluation suggest that the current hypnosis model may be useful for assessing autonomic physiological associations with changes in BIS values, thus motivating us to proceed with a larger investigation in trauma center nurses and physicians.

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The magnitude of parasympathetic reflex-mediated bronchoconstriction during histamine infusion was compared in anesthetized paralyzed newborn and adult guinea pigs. The animals were ventilated using a constant-flow ventilator, and the conductance and compliance of the respiratory system were continuously monitored. We found that reactivity to histamine infusion was less in newborns than in adults, because newborns required a larger dose of histamine than adults (300 vs. 125 ng.kg-1.s-1) to produce an equivalent decrease in conductance (42 +/- 13 vs. 42 +/- 15%). Vagal interruption by bilateral cervical vagotomy or muscarinic blockade with atropine (3 mg/kg) significantly reduced the bronchoconstrictor response to histamine in adults. By contrast, neither vagotomy nor atropine significantly changed this response in the newborns. These results indicate the lack of a vagal component in the bronchoconstriction that histamine induced in the newborns. Their relative unresponsiveness to histamine might partly be related to the fact that, in the newborn, histamine mainly acts directly via its airway receptors.

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Cystic fibrosis is the most common autosomal-recessive metabolic disease in the Western world. Impaired trans-membrane chloride transport via the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes thickened body fluids. In the respiratory system, this leads to chronic suppurative cough and recurrent pulmonary infective exacerbations, resulting in progressive lung damage and respiratory failure. Whilst the impact of bacterial infections on CF lung disease has long been recognized, our understanding of pulmonary mycosis is less clear. The range and detection rates of fungal taxa isolated from CF airway samples are expanding, however, in the absence of consensus criteria and univocal treatment protocols for most respiratory fungal conditions, interpretation of laboratory reports and the decision to treat remain challenging. In this review, we give an overview on fungal airway infections in CF and CF-lung transplant recipients and focus on the most common fungal taxa detected in CF, Aspergillus fumigatus, Candida spp., Scedosporium apiospermum complex, Lomentospora species, and Exophiala dermatitidis, their clinical presentations, common treatments and prophylactic strategies, and clinical challenges from a physician’s point of view.

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We investigated whether amygdala activation, autonomic responses, respiratory responses, and facial muscle activity (measured over the brow and cheek [fear grin] regions) are all sensitive to phobic versus nonphobic fear and, more importantly, whether effects in these variables vary as a function of both phobic and nonphobic fear intensity. Spider-phobic and comparably low spider-fearful control participants imagined encountering different animals and rated their subjective fear while their central and peripheral nervous system activity was measured. All measures included in our study were sensitive to variations in subjective fear, but were related to different ranges and positions on the subjective fear level continuum. Left amygdala activation, heart rate, and facial muscle activity over the cheek region captured fear intensity variations even within narrowly described regions on the fear level continuum (here within extremely low levels of fear and within considerable phobic fear). Skin conductance and facial muscle activity over the brow region did not capture fear intensity variations within low levels of fear: skin conductance mirrored only extreme levels of fear, and activity over the brow region distinguished phobic from nonphobic fear but also low-to-moderate and high phobic fear. Finally, respiratory measures distinguished phobic from nonphobic fear with no further differentiation within phobic and nonphobic fear. We conclude that a careful consideration of the measures to be used in an investigation and the population to be examined can be critical in order to obtain significant results.

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Accumulating evidence indicates that psychological and neurophysiological processes interconnect and interact to activate the body’s stress system and to trigger and maintain functional somatic symptoms. This study used the Early Life Stress Questionnaire, Depression Anxiety Stress Scales and biological markers (heart rate, heart rate variability, skin conductance, C-reactive protein (CRP) titre, respiratory rate, and accuracy and reaction time in an emotion-face identification task), to examine childhood adversity, psychological distress and stress-system activation in 35 children and adolescents (23 girls and 12 boys, 9–17 years old) disabled by chronic pain (vs two groups of age- and sex-matched healthy controls). Patients reported more early-life stress ( U = 798.5, p = .026) and more psychological distress ( U = 978, p < .001). They showed activation of the autonomic system: elevated heart rate ( U = 862.5, p = .003), elevated electrodermal activity ( U = 804.5, p = .024) and lower heart rate variability in the time domain ( U = 380.5, p = .007) and frequency domain ( U = 409.5, p = .017). The group showed an upward shift of CRP titres (with 75th and 90th CRP percentiles of 4.5 and 10.5 mg/L, respectively), suggesting the activation of the immune–inflammatory system. Elevated CRP titres were associated with elevated heart rate ( p = .028). There were no differences in respiratory rate or in accuracy and reaction time in the emotion-face identification task. The results indicate that interventions for children and adolescents with chronic pain need a multidisciplinary mind–body approach that concurrently addresses psychological distress, physical impairment and stress-system dysregulation.

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Cystic fibrosis (CF) is a genetic disease that causes absence or dysfunction of a protein named transmembrane conductance regulatory protein (CFTR) that works as an anion channel. As a result, the secretions of the organs where CFTR is expressed are very viscous, so their functionality is altered. The main cause of morbidity is due to the involvement of the respiratory system as a result of recurrent respiratory infections by different pathogens. In recent decades, survival has been increasing, rising by around age 50. This is due to the monitoring of patients in multidisciplinary units, early diagnosis with neonatal screening, and advances in treatments. In this chapter, we will approach the different therapies used in CF for the treatment of symptoms, obstruction, inflammation, and infection. Moreover, we will discuss specific and personalized treatments to correct the defective gene and repair the altered protein CFTR. The obstacle for personalized CF treatment is to predict the drug response of patients due to genetic complexity and heterogeneity of uncommon mutations.

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A tracking impedance estimation technique was developed to follow the changes in total respiratory impedance (Zrs) during slow total lung capacity maneuvers in six anesthetized and mechanically ventilated BALB/c mice. Zrs was measured with the wave-tube technique and pseudorandom forced oscillations at nine frequencies between 4 and 38 Hz during inflation from a transrespiratory pressure of 0-20 cmH2O and subsequent deflation, each lasting for ∼20 s. Zrs was averaged for 0.125 s and fitted by a model featuring airway resistance (Raw) and inertance, and tissue damping and elastance ( H). Lower airway conductance (Glaw) was linearly related to volume above functional residual capacity (V) between 0 and 75-95% maximum V, with a mean slope of dGlaw/dV = 13.6 ± 4.6 cmH2O-1 · s-1. The interdependence of Raw and H was characterized by two distinct and closely linear relationships for the low- and high-volume regions, separated at ∼40% maximum V. Comparison of Raw with the highest-frequency resistance of the total respiratory system revealed a marked volume-dependent contribution of tissue resistance to total respiratory system resistance, resulting in the overestimation of Raw by 19 ± 8 and 163 ± 40% at functional residual capacity and total lung capacity, respectively, whereas the lowest frequency reactance was proportional to H; these findings indicate that single-frequency resistance values may become inappropriate as surrogates of Raw when tissue impedance is changing.

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Background: Formaldehyde (HCOH) is the most abundant airborne carbonyl indoor volatile organic compound (VOC), which is well-known to cause serious health effects such as respiratory system disease, immune system disorders, and central nervous system damage. Methods: The interaction between HCOH and intrinsic, congeners of Au, Ag, Cu-doped SWCNTs were investigated by density functional theory (DFT) to evaluate the detection of formaldehyde. Results: The results demonstrated that the less adsorption on the surface of intrinsic SWCNT, an HCOH molecule tended to be chemisorbed to the Au, Ag, and Cu atoms of doped SWCNT with larger binding energy of 0.4-0.8 eV and smaller binding distance of 1.9-2.3 Å. Furthermore, charge transfer and density of state studies indicated tha t the electronic properties changed evidently in the most stable HCOH-doped SWCNT systems, mainly at the region of -5.5 to -4.5 eV and Fermi level. Conclusion: More importantly, the adsorption of HCOH affected the electronic conductance of doped SWCNT. It is expected that the results obtained in this study could provide a useful theoretical guidance for the investigation of molecular films interface bonding and design of HCOH sensing devices.

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Since its introduction in the clinical practice, body plethysmography has assisted pneumologists in the diagnosis of respiratory diseases and patients’ follow-up, by providing easy assessment of absolute lung volumes and airway resistance. In the last decade, emerging evidence suggested that estimation of alveolar pressure by electronically-compensated plethysmographs may contain information concerning the mechanics of the respiratory system which goes beyond those provided by the simple value of airway resistance or conductance. Indeed, the systematic study of expiratory alveolar pressure-flow loops produced during spontaneous breathing at rest has shown that the marked expansion of expiratory loops in chronic obstructive pulmonary disease patients mainly reflects the presence of tidal expiratory flow-limitation. The presence of this phenomenon can be accurately predicted on the basis of loop-derived parameters. Finally, we present results suggesting that plethysmographic alveolar pressure may be used to estimate non-invasively intrinsic positive end-expiratory pressure (PEEPi) in spontaneously breathing patients, a task which previously could be only accomplished by introducing a balloon-tipped catheter in the esophagus.

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During breathing under sedation via a two-way valve, airflow (V), volume (delta V), and airway pressure (P) were recorded in eight normal (N) infants, seven with reversible obstructive airway disease (ROAD), and seven with chronic lung disease (CLD). Intermittently, expiratory volume clamping (EVC) was applied, involving selective occlusion of the expiratory valve for three to five breaths. The latter produced cumulative increases in delta V that, due to progressive recruitment of the Hering-Breuer reflex, were accompanied by increasing expiratory plateaus in P (i.e., apneas). The resultant passive inflation delta V-P relationships were closely approximated by the expression: delta V = aP2 + bP + c, wherein a represented the pressure-related changes in chord compliance (Crs), b the Crs at P = 0, and c the difference between the dynamic end-expiratory and relaxation volumes of the respiratory system. Relative to N, the ROAD and CLD infants had significantly reduced weight-specific values of a/kg, their b/kg values were increased, whereas the c/kg measurements did not significantly vary. Moreover, for each subject we determined the net Crs/kg obtaining at P = 20 cmH2O (i.e., Crs20/kg), an estimate of the net deflation compliance; the passive respiratory time constant (tau rs) based on the slope of the expired delta V/V relationship; and the respiratory system conductance (Grs/kg). Relative to N, the mean Crs20/kg was significantly reduced only in the infants with CLD and, due to increases in tau rs, both patient groups depicted significantly diminished values of Grs/kg, suggesting the presence of airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

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In 14 healthy male subjects we studied the effects of rib cage and abdominal strapping on lung volumes, airway resistance (Raw), and total respiratory resistance (Rrs) and reactance (Xrs). Rib cage, as well as abdominal, strapping caused a significant decrease in vital capacity (respectively, -36 and -34%), total lung capacity (TLC) (-31 and -27%), functional residual capacity (FRC) (-28 and -28%), and expiratory reserve volume (-40 and -48%) and an increase in specific airway conductance (+24 and +30%) and in maximal expiratory flow at 50% of control TLC (+47 and +42%). The decrease of residual volume (RV) was significant (-12%) with rib cage strapping only. Abdominal strapping resulted in a minor overall increase in Rrs, whereas rib cage strapping produced a more marked increase at low frequencies; thus a frequency dependence of Rrs was induced. A similar pattern, but with lower absolute values, of Rrs was obtained by thoracic strapping when the subject was breathing at control FRC. Xrs was decreased, especially at low frequencies, with abdominal strapping and even more with thoracic strapping; thus the resonant frequency of the respiratory system was shifted toward higher frequencies. Partitioning Rrs and Xrs into resistance and reactance of lungs and chest wall demonstrated that the different effects of chest wall and abdominal strapping on Rrs and Xrs reflect changes mainly of chest wall mechanics.

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Cystic fibrosis is an autosomal recessive genetic disorder, characterized by mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to abnormality in the chloride channels of the mucus and sweat producing glands. Multiple organs systems are affected in this disorder, like respiratory system and gastrointestinal tract, severely impacting the patient’s quality of life, eventually leading on to several complications and death. Since the uncovering of the underlying genetic defect in cystic fibrosis (CF), our knowledge of the disease process has increased substantially, but we still lack a holistic approach to its management, which comprises of multiple facades, requiring both pharmacological and non-pharmacological or rehabilitatory approaches. So far, the therapeutic options were limited to targeting the consequences and complications of the disease, such as respiratory infection, mucus retention, pancreatic insufficiency, etc., but now several promising therapies may be able to address the underlying pathology rather than its long-term effects. This review summarizes the current and upcoming pharmacological options for CF, such as those targeting the CFTR gene defect directly, including gene editing, CFTR correctors and potentiators; drugs targeting the epithelial sodium channels (ENaC inhibitors); repositioning of some existing drugs and evaluating their role in CF; and understanding the disease better by transcriptomic approaches and the role of gut microbiota in the disease process and severity.

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The preservation of cellular homeostasis requires the synthesis of new proteins (proteostasis) and organelles, and the effective removal of misfolded or impaired proteins and cellular debris. This cellular homeostasis involves two key proteostasis mechanisms, the ubiquitin proteasome system and the autophagy–lysosome pathway. These catabolic pathways have been known to be involved in respiratory exacerbations and the pathogenesis of various lung diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF), acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and coronavirus disease-2019 (COVID-19). Briefly, proteostasis and autophagy processes are known to decline over time with age, cigarette or biomass smoke exposure, and/or influenced by underlying genetic factors, resulting in the accumulation of misfolded proteins and cellular debris, elevating apoptosis and cellular senescence, and initiating the pathogenesis of acute or chronic lung disease. Moreover, autophagic dysfunction results in an impaired microbial clearance, post-bacterial and/or viral infection(s) which contribute to the initiation of acute and recurrent respiratory exacerbations as well as the progression of chronic obstructive and restrictive lung diseases. In addition, the autophagic dysfunction-mediated cystic fibrosis transmembrane conductance regulator (CFTR) immune response impairment further exacerbates the lung disease. Recent studies demonstrate the therapeutic potential of novel autophagy augmentation strategies, in alleviating the pathogenesis of chronic obstructive or restrictive lung diseases and exacerbations such as those commonly seen in COPD, CF, ALI/ARDS and COVID-19.

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AbstractSocial anxiety disorder (SAD) is commonly diagnosed during adolescence and is associated with psychological stress reactivity and heightened physiological arousal. No study, however, has systematically examined which aspects of autonomic nervous system function mediate likely links between stress sensitivity and social anxiety symptoms in adolescents. Here, we assessed 163 adolescents (90 females; 12.29 ± 1.39 years) with respect to life stress and social anxiety symptoms, and measured respiratory sinus arrhythmia (RSA) and skin conductance levels (SCL) during a psychosocial stress paradigm. We operationalized stress sensitivity as the residual variance in subjective stress severity after accounting for objective severity and changes in autonomic regulation using standardized change scores in RSA and SCL. In females only, stress sensitivity and social anxiety symptoms were significantly correlated with each other (p < .001) and with autonomic regulation during both reactivity and recovery (all ps < 0.04). Further, sympathetic nervous system dominance during recovery specifically mediated associations between stress sensitivity and social anxiety symptoms (B = 1.06, 95% CI: 0.02–2.64). In contrast, in males, stress sensitivity, autonomic regulation during reactivity or recovery, and social anxiety symptoms were not significantly associated (all ps > 0.1). We interpret these results in the context of psychobiological models of SAD and discuss implications for interventions targeting autonomic processes.

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Cystic fibrosis (CF) is a common multi-system genetically inherited condition, predominately found in individuals of Caucasian decent. Since the identification of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene in 1989, and the subsequent improvement in understanding of CF pathophysiology, significant increases in life-expectancy have followed. Initially this was related to improvements in the management and systems of care for treating the various affected organ systems. These cornerstone treatments are still essential for CF patients born today. However, over the last decade, the major advance has been in therapies that target the resultant genetic defect: the dysfunctional CFTR protein. Small molecule agents that target this dysfunctional protein via a variety of mechanisms have led to lung function improvements, reductions in pulmonary exacerbation rates and increases in weight and quality-of-life indices. As more patients receive these agents earlier and earlier in life, it is likely that general CF care will increasingly pivot around these specific therapies, although it is also likely that effects other than those identified in the initial trials will be discovered and need to be managed. Despite great excitement for modulator therapies, they are unlikely to be suitable or available for all; whether this is due to a lack of availability for specific CFTR mutations, drug-reactions or the health economic set-up in certain countries. Nevertheless, the CF community must be applauded for its ongoing focus on research and development for this life-limiting disease. With time, personalised individualised therapy would ideally be the mainstay of CF care.

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The effects of tidal volume amplitude on bronchopulmonary reactivity were investigated in three groups of 14 anesthetized paralyzed mechanically ventilated guinea pigs. Animals of group 1 served as control; in animals of group 2, both the sympathetic and parasympathetic nervous systems were blocked; in animals of group 3, only the parasympathetic system was blocked. In each group, the animals were randomly divided into two subgroups characterized by their ventilatory pattern: rate of 60/min with a 6-ml/kg tidal volume or rate of 40/min with a 9-ml/kg tidal volume. Bronchopulmonary reactivity to infused histamine was assessed by the respiratory compliance and conductance values measured during bronchoconstriction and expressed as a percentage of the corresponding basal values. In group 1 the animals ventilated with a 9-ml/kg tidal volume were found significantly less reactive than those ventilated with a 6-ml/kg tidal volume. This difference was abolished in groups 2 and 3. These results demonstrate that the effects of increased tidal volume on bronchopulmonary reactivity are vagally mediated and suggest that the decrease observed in histamine-induced bronchoconstriction is mainly due to reflex effects evoked by stretch receptor stimulation.

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We studied the kinetics of proximal and distal bronchial response to histamine aerosol in healthy anesthetized and mechanically ventilated rabbits up to 60 min after histamine administration using a novel xenon-enhanced synchrotron radiation computed tomography imaging technique. Individual proximal airway constriction was assessed by measuring the luminal cross-sectional area. Distal airway obstruction was estimated by measuring the ventilated alveolar area after inhaled xenon administration. Respiratory system conductance was assessed continuously. Proximal airway cross-sectional area decreased by 57% of the baseline value by 20 min and recovered gradually but incompletely within 60 min. The ventilated alveolar area decreased immediately after histamine inhalation by 55% of baseline value and recovered rapidly thereafter. The results indicate that the airway reaction to inhaled histamine and the subsequent recovery are significantly slower in proximal than in distal bronchi in healthy rabbit. The findings suggest that physiological reaction mechanisms to inhaled histamine in the airway walls of large and small bronchi are not similar.

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BACKGROUNDImpaired growth and development of the respiratory system during fetal and early postnatal life may have important implications for lung development and later lung health. The aim of this study was to examine the association of diminished premorbid airway function, prior wheezing, and maternal smoking with airway function at 1 year of age.METHODSRespiratory function was measured at the end of the first year in 100 of 108 healthy term infants (93%) in whom similar measurements had been undertaken prior to any respiratory illness at 8 weeks. Physician diagnosed wheezing episodes were identified retrospectively from medical records.RESULTSAt 1 year specific airway conductance during end expiration (sGawee; /s/kPa) was significantly diminished in those infants with prior wheezing (95% CI wheeze/no wheeze –0.76 to –0.14), mothers who smoked (95% CI smoke/no smoke –0.81 to –0.27), a family history of asthma (95% CI family history/no family history –0.62 to 0.00), or diminished premorbid sGawee (95% CI –0.13 to –0.43/s/kPa per unit reduction sGawee at 8 weeks). In a multivariate model only maternal smoking and diminished premorbid sGaweewere independently associated with diminished sGawee at 1 year.CONCLUSIONSDiminished airway function at the end of the first year appears to be mediated by impaired airway development during early life as well as by exposure to maternal smoking. These findings are consistent with the hypothesis that, at a population level, diminished premorbid airway function provides the link between wheezing lower respiratory illness and diminished airway function at 1 year. Maternal smoking remains an important and avoidable cause of impaired airway development and function in infancy.

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We have recently demonstrated that changes in the work of breathing during maximal exercise affect leg blood flow and leg vascular conductance (C. A. Harms, M. A. Babco*ck, S. R. McClaran, D. F. Pegelow, G. A. Nickele, W. B. Nelson, and J. A. Dempsey. J. Appl. Physiol. 82: 1573–1583, 1997). Our present study examined the effects of changes in the work of breathing on cardiac output (CO) during maximal exercise. Eight male cyclists [maximal O2 consumption (V˙o 2 max): 62 ± 5 ml ⋅ kg−1 ⋅ min−1] performed repeated 2.5-min bouts of cycle exercise atV˙o 2 max. Inspiratory muscle work was either 1) at control levels [inspiratory esophageal pressure (Pes): −27.8 ± 0.6 cmH2O], 2) reduced via a proportional-assist ventilator (Pes: −16.3 ± 0.5 cmH2O), or 3) increased via resistive loads (Pes: −35.6 ± 0.8 cmH2O). O2 contents measured in arterial and mixed venous blood were used to calculate CO via the direct Fick method. Stroke volume, CO, and pulmonary O2 consumption (V˙o 2) were not different ( P > 0.05) between control and loaded trials atV˙o 2 max but were lower (−8, −9, and −7%, respectively) than control with inspiratory muscle unloading atV˙o 2 max. The arterial-mixed venous O2difference was unchanged with unloading or loading. We combined these findings with our recent study to show that the respiratory muscle work normally expended during maximal exercise has two significant effects on the cardiovascular system: 1) up to 14–16% of the CO is directed to the respiratory muscles; and 2) local reflex vasoconstriction significantly compromises blood flow to leg locomotor muscles.

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Airway distensibility appears to be unaffected by airway smooth muscle (ASM) tone, despite the influence of ASM tone on the airway diameter-pressure relationship. This discrepancy may be because the greatest effect of ASM tone on airway diameter-pressure behavior occurs at low transpulmonary pressures, i.e., low lung volumes, which has not been investigated. Our study aimed to determine the contribution of ASM tone to airway distensibility, as assessed via the forced oscillation technique (FOT), across all lung volumes with a specific focus on low lung volumes. We also investigated the accompanying influence of ASM tone on peripheral airway closure and heterogeneity inferred from the reactance versus lung volume relationship. Respiratory system conductance and reactance were measured using FOT across the entire lung volume range in 22 asthma subjects and 19 healthy controls before and after bronchodilator. Airway distensibility (slope of conductance vs. lung volume) was calculated at residual volume (RV), functional residual capacity (FRC), and total lung capacity. At baseline, airway distensibility was significantly lower in subjects with asthma at all lung volumes. After bronchodilator, distensibility significantly increased at RV (64.8%, P < 0.001) and at FRC (61.8%, P < 0.01) in subjects with asthma but not in control subjects. The increased distensibility at RV and FRC in asthma were not associated with the accompanying changes in the reactance versus lung volume relationship. Our findings demonstrate that, at low lung volumes, ASM tone reduces airway distensibility in adults with asthma, independent of changes in airway closure and heterogeneity.

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Abstract Background: Endotracheal suctioning of respiratory secretions is one of the most common causes of pain and discomfort in Intensive Care Unit environment. The electrical properties of the skin, also known as electrodermal activity (EDA), are considered as an indirect measure of autonomous nervous system. Aim: This study explores EDA changes during endotracheal suction in sedated adult critical care patients; and compares these changes to other monitoring parameters. Materials and methods: Skin conductance variability, selected hemodynamic and respiratory parameters, bispectral index (BIS) and ambient noise level, were monitored during 4 hour routine daytime intensive care nursing and treatment in an adult Intensive Care Unit. 4h-measurements were divided into 2 groups, based upon the sedation level (group A: Ramsay sedation scale 2-4 and group B: 5-6 respectively) of the patients. Selected recordings before and after endotracheal suction (stress events) were performed. Seven stress events from Group A and 17 from Group B were included for further analysis. Patients’ demographics, laboratory exams and severity scores were recorded. Pain status evaluation before every event was also performed via 2 independent observers. Results: In both groups the rate of EDA changes was greater than in other monitoring parameters. Yet, in group A only selected parameters were significantly changed after the start of the procedure, while in group B, every parameter showed significant change (p<0.05). Groups were similar for other co-founding factors. Conclusion: EDA measurements are more sensitive to stress stimuli, than cardiovascular, respiratory or even BIS monitoring. Deeper sedation seems to affect more the intensity of EDA changes during suction.

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ABSTRACT Cystic fibrosis (CF) is a genetic disease caused by recessive mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and is associated with prevalent and chronic Pseudomonas aeruginosa lung infections. Despite numerous studies that have sought to elucidate the role of CFTR in the innate immune response, the links between CFTR, innate immunity, and P. aeruginosa infection remain unclear. The present work highlights the zebrafish as a powerful model organism for human infectious disease, particularly infection by P. aeruginosa. Zebrafish embryos with reduced expression of the cftr gene (Cftr morphants) exhibited reduced respiratory burst response and directed neutrophil migration, supporting a connection between cftr and the innate immune response. Cftr morphants were infected with P. aeruginosa or other bacterial species that are commonly associated with infections in CF patients, including Burkholderia cenocepacia, Haemophilus influenzae, and Staphylococcus aureus. Intriguingly, the bacterial burden of P. aeruginosa was found to be significantly higher in zebrafish Cftr morphants than in controls, but this phenomenon was not observed with the other bacterial species. Bacterial burden in Cftr morphants infected with a P. aeruginosa ΔLasR mutant, a quorum sensing-deficient strain, was comparable to that in control fish, indicating that the regulation of virulence factors through LasR is required for enhancement of infection in the absence of Cftr. The zebrafish system provides a multitude of advantages for studying the pathogenesis of P. aeruginosa and for understanding the role that innate immune cells, such as neutrophils, play in the host response to acute bacterial infections commonly associated with cystic fibrosis.

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The contribution of the nonadrenergic inhibitory system to airway responses to infusion of 5-hydroxytryptamine (5-HT) was evaluated in anesthetized, tracheotomized, and paralyzed young (13 days) and adult (82 days) guinea pigs. Animals were mechanically ventilated by a constant flow ventilator. Compliance (C) and conductance (G) of the respiratory system were continuously monitored. Three series of experiments were performed involving intravenous pretreatment with 1) atropine (3 mg/kg) and propranolol (1 mg/kg); 2) atropine (3 mg/kg), propranolol (1 mg/kg), and phentolamine (2 mg/kg); and 3) atropine (3 mg/kg) and hexamethonium (2 mg/kg). 5-HT was then intravenously infused for 5 min at a rate of 40 ng.kg-1.s-1 in adults and 60 ng.kg-1.s-1 in young guinea pigs to obtain the same degree of bronchoconstriction in both groups. At the 3rd min of the infusion, bilateral cervical vagotomy was performed and C and G were measured at the maximal response, 1-2 min thereafter. Vagotomy increased bronchoconstriction (P less than 0.01) in both young animals and adults. Phentolamine did not modify this increase, but hexamethonium completely inhibited it. These results indicate that, in adult and young guinea pigs, 5-HT infusion induces reflex activation of the nonadrenergic inhibitory system, which in turn modulates the bronchoconstrictor responses to 5-HT. This neural modulation is not mediated by an alpha-adrenergic pathway.

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AbstractExposure to threat increases the risk for internalizing problems in adolescence. Deficits in integrating bodily cues into representations of emotion are thought to contribute to internalizing problems. Given the role of the medial prefrontal cortex in regulating bodily responses and integrating them into representations of emotional states, coordination between activity in the medial prefrontal cortex and autonomic nervous system responses may be influenced by past threat exposure with consequences for the emergence of internalizing problems. A sample of 179 Mexican-origin adolescents (88 female) reported on neighborhood and school crime, peer victimization, and discrimination when they were 10–16 years old. At age 17, participants underwent a functional neuroimaging scan during which they viewed pictures of emotional faces while respiratory sinus arrhythmia (RSA) and skin conductance responses were measured. Adolescents also reported symptoms of internalizing problems. Greater exposure to threats across adolescence was associated with more internalizing problems. Threat exposure was also associated with stronger negative coupling between the ventromedial prefrontal cortex and RSA. Stronger negative ventromedial prefrontal cortex–RSA coupling was associated with fewer internalizing problems. These results suggest the degree of coordinated activity between the brain and parasympathetic nervous system is both enhanced by threat experiences and decreased in adolescents with more internalizing problems.

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The most common mutation of the cystic fibrosis (CF) gene, the deletion of Phe508, encodes a protein (ΔF508-CFTR) that fails to fold properly, thus mutated ΔF508-cystic fibrosis transmembrane conductance regulator (CFTR) is recognized and degraded via the ubiquitin-proteasome endoplasmic reticulum-associated degradation pathway. Chemical and pharmacological chaperones and ligand-induced transport open options for designing specific drugs to control protein (mis)folding or transport. A class of compounds that has been proposed as having potential utility in ΔF508-CFTR is that which targets the molecular chaperone and proteasome systems. In this study, we have selected deoxyspergualin (DSG) as a reference molecule for this class of compounds and for ease of cross-linking to human serum albumin (HSA) as a protein transporter. Chemical cross-linking of DSG to HSA via a disulfide-based cross-linker and its administration to cells carrying ΔF508-CFTR resulted in a greater enhancement of ΔF508-CFTR function than when free DSG was used. Function of the selenium-dependent oxidoreductase system was required to allow intracellular activation of HSA-DSG conjugates. The principle that carrier proteins can deliver pharmacological chaperones to cells leading to correction of defective CFTR functions is therefore proven and warrants further investigations.

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Cystic fibrosis (CF) is said to be the most common lethal inherited disease of the white population. It affects the exocrine glands of body, primarily of the gastrointestinal and respiratory system. CF is caused by one of a large numbers of mutations of the gene for a protein called the cystic fibrosis transmembrane conductance regulator (CFTR). This CFTR regulates chloride and sodium transport across epithelial membranes. The main complications involve in the lungs, with damage to the small and large airways by chronic and recurrent bacterial infections. Other major consequences include pancreatic malfunction, leading to malabsorption of nutrients and vitamins with consequent impaired growth and development and in older patient diabetes. Diagnosis is usually done by sweat test or identification of two CF-causing mutations in patients with characteristics symptoms. Treatment is supportive through aggressive multidisciplinary care. The prognosis of CF has improved due to earlier diagnosis through screening, better treatment and access to health care. Although CF is a rare disease in Bangladesh, but its possibility should be kept in mind in appropriate circ*mstances.Bangladesh J Child Health 2016; VOL 40 (3) :174-178

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To test the hypothesis that parasympathetic airway tone may affect airway responsiveness, we measured bronchoconstrictor responses to intravenous bethanechol (BCh) in anesthetized vagotomized rats with and without background vagal nerve stimulation and developed a predictive model based on pharmacological additivity between endogenous and intravenous agonists. A high degree of agreement (r2 = 0.93) between the measured and predicted responses indicated that intravenous BCh and parasympathetic tone had bronchoconstrictor effects that were pharmacologically additive. An expansion of the additive model was used to determine that the percentage of decrease in respiratory system conductance (Grs) would be a measure of airway response independent of background parasympathetic tone. As predicted, the percentage of decrease in Grs after intravenous BCh was minimally affected by background vagal stimulation. However, the percentage of decrease in Grs was augmented by vagal stimulation for intravenous 5-hydroxytryptamine hydrochloride, a known parasympathetic neuromodulator, and for methacholine, an agonist with nicotinic as well as muscarinic activity (P < 0.02 for each agonist). We conclude that airway parasympathetic tone can be a source of variability for airway responsiveness when substances having neuromodulatory activity are involved in the provocative challenge.

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Cystic fibrosis (CF), an epithelial cell transport disorder caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, is not generally associated with malformations of the central nervous system (CNS). This report describes two African-American children who died at less than 2 years of age with known Chiari I malformations and were found, unexpectedly at autopsy, to have the classic pancreatic and respiratory changes of CF. Both patients had suffered from failure to thrive that had been attributed to their CNS malformations. One child also had recurrent pneumonia and died with Pseudomonas sepsis. Mutational analysis for > 70 common CFTR mutations identified a single delta F508 mutation in one patient and a single 3120 + 1G to A mutation in the other. Their second CFTR mutations were not identified. The association of CF with Chiari I malformation is not likely to be purely coincidental, as the probability of such an occurrence in African-Americans is greater than one in 7,500,000 patients. It is possible that the CFTR gene may play a previously unrecognized role in CNS development. Alternatively, this CNS abnormality may be acquired due to the metabolic and electrolyte imbalances that characteristically occur in CF.

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Background: Lumacaftor/ivacaftor (LUM/IVA) has shown modest benefits in previous research, but the exact effects in the cystic fibrosis (CF) lung remain unclear. This study aims to offer novel information on the mode of action of the cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drug by assessing lung structure and function using functional respiratory imaging (FRI). Methods: CF patients aged ⩾12 years hom*ozygous for F508del were recruited in an open-label study. Before and after 12 weeks of treatment with LUM/IVA, FRI was used to visualize regional information, such as air trapping, lobar volume and airway wall volume. Secondary outcomes included the CF-CT scoring system, spirometry, the Cystic Fibrosis Questionnaire–Revised (CFQ-R) questionnaire, exercise tolerance and nutritional status. Results: Of the 12 patients enrolled in the study, 11 completed all study visits. Concerning the FRI parameters, hyperinflation of the lung decreased, indicated by a reduction in air trapping and lobar volume at expiration. Also, a decrease in airway wall volume and a redistribution of pulmonary blood volume were noted, which might be related to a decrease in mucus impaction. Airway resistance, airway volume, internal airflow distribution and aerosol deposition pattern did not show significant changes. No significant improvements were found in any of the CF-CT scores or in the spirometric parameters. Other secondary outcomes showed similar results compared with previous research. Correlations at baseline were found between FRI and conventional outcomes, including physical functioning, spirometry and CF-CT scores. Conclusions: LUM/IVA decreased lung hyperinflation in combination with a potential decrease in mucus impaction, which can be related to an improved mucociliary transport. These results indicate that several FRI parameters, reflecting regional and distal lung structures, are more sensitive to changes caused by LUM/IVA than conventional respiratory outcomes.

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Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, including the pancreas, hepatobiliary system and reproductive organs; however, lung disease is responsible for the majority of morbidity and mortality. Management of CF involves CF transmembrane conductance regulator (CFTR) modulator agents including corrector drugs to augment cellular trafficking of mutant CFTR as well as potentiators that open defective CFTR channels. These therapies are poised to help most individuals with CF, with the notable exception of individuals with class I mutations where full-length CFTR protein is not produced. For these mutations, gene replacement has been suggested as a potential solution.In this work, we used a helper-dependent adenoviral vector (HD-CFTR) to express CFTR in nasal epithelial cell cultures derived from CF subjects with class I CFTR mutations.CFTR function was significantly restored in CF cells by HD-CFTR and reached healthy control functional levels as detected by Ussing chamber and membrane potential (FLIPR) assay. A dose–response relationship was observed between the amount of vector used and subsequent functional outcomes; small amounts of HD-CFTR were sufficient to correct CFTR function. At higher doses, HD-CFTR did not increase CFTR function in healthy control cells above baseline values. This latter observation allowed us to use this vector to benchmark in vitro efficacy testing of CFTR-modulator drugs.In summary, we demonstrate the potential for HD-CFTR to inform in vitro testing and to restore CFTR function to healthy control levels in airway cells with class I or CFTR nonsense mutations.

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BackgroundPseudomonas aeruginosa lung infections are a huge problem in ventilator-associated pneumonia, cystic fibrosis (CF) and in chronic obstructive pulmonary disease (COPD) exacerbations. This bacterium secretes virulence factors that may subvert host innate immunity.ObjectiveWe evaluated the effect of P. aeruginosa elastase LasB, an important virulence factor secreted by the type II secretion system, on ion transport, innate immune responses and epithelial repair, both in vitro and in vivo.MethodsWild-type (WT) or cystic fibrosis transmembrane conductance regulator (CFTR)-mutated epithelial cells (cell lines and primary cells from patients) were treated with WT or ΔLasB pseudomonas aeruginosa O1 (PAO1) secretomes. The effect of LasB and PAO1 infection was also assessed in vivo in murine models.ResultsWe showed that LasB was the most abundant protein in WT PAO1 secretomes and that it decreased epithelial CFTR expression and activity. In airway epithelial cell lines and primary bronchial epithelial cells, LasB degraded the immune mediators interleukin (IL)-6 and trappin-2, an important epithelial-derived antimicrobial molecule. We further showed that an IL-6/STAT3 signalling pathway was downregulated by LasB, resulting in inhibition of epithelial cell repair. In mice, intranasally instillated LasB induced significant weight loss, inflammation, injury and death. By contrast, we showed that overexpression of IL-6 and trappin-2 protected mice against WT-PAO1-induced death, by upregulating IL-17/IL-22 antimicrobial and repair pathways.ConclusionsOur data demonstrate that PAO1 LasB is a major P. aeruginosa secreted factor that modulates ion transport, immune response and tissue repair. Targeting this virulence factor or upregulating protective factors such as IL-6 or antimicrobial molecules such as trappin-2 could be beneficial in P. aeruginosa-infected individuals.

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In recent years, the microbiome has been recognized as a key regulator of immune responses. Evidence suggests that changes in the microbiome can lead to chronic disease and even exacerbation of the disease. Impairment of innate immunity resulting from microbial incompatibility may worsen host susceptibility to infection and exacerbate chronic lung diseases. Specific microbes play a key role in improving immune responses and microbial incompatibility is involved in chronic lung diseases such as asthma, chronic obstructive pulmonary disease, and Cystic Fibrosis (CF). CF is an extremely complex disease that results from a gene mutation. Lack of expression of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) has late complications. Incompatibility in lung microbiota is associated with chronic lung diseases, but it is not determined whether this incompatibility can cause health problems or ineffective regulation of immune response create the disease and its progression. In the CF, due to the deficiency of the immune system, many opportunistic microorganisms, including Pseudomonas. aeruginosa or Staphylococcus aureus are colonized in the patient’s lung and due to an immunodeficiency causedby a defect in the system CFTR, lungs are unable to clear the bacteria that leads to severe pulmonary complications and respiratory and digestive problems in such patients. Therefore, in these patients, the microbiome contributes to dysfunctional immune responses and disease exacerbations. This review summarizes the impact of the microbiome on host immune responses and its relationship with CF to explore the role of the microbiome in causing CF.

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Cystic fibrosis mice have been generated by gene targeting but show little lung disease without repeated exposure to bacteria. We asked if murine mucosal defenses and airway surface liquid (ASL) Cl−were altered by the ΔF508 cystic fibrosis transmembrane conductance regulator mutation. Naive ΔF508 −/− and +/− mice showed no pulmonary inflammation and after inhaled Pseudomonas aeruginosa had similar inflammatory responses and bacterial clearance rates. We therefore investigated components of the innate immune system. Bronchoalveolar lavage fluid from mice killed Escherichia coli, and the microbicidal activity was inhibited by NaCl. Because β-defensins are salt-sensitive epithelial products, we looked for pulmonary β-defensin expression. A mouse hom*olog of human β-defensin-1 (termed “MBD-1”) was identified; the mRNA was expressed in the lung. Using a radiotracer technique, ASL volume and Cl−concentration ([Cl−]) were measured in cultured tracheal epithelia from normal and ΔF508 −/− mice. The estimated ASL volume was similar for both groups. There were no differences in ASL [Cl−] in ΔF508 −/− and normal mice (13.8 ± 2.6 vs. 17.8 ± 5.6 meq/l). Because ASL [Cl−] is low in normal and mutant mice, salt-sensitive antimicrobial factors, including MBD-1, may be normally active.

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The basic therapy of cystic fibrosis is currently aimed at slowing down the pathological processes associated with a decrease in the CFTR protein activity (cystic fibrosis transmembrane conductance regulator) in the gastrointestinal tract and the respiratory system. The pancreatic insufficiency is well compensated by replacement therapy with microsphere enzyme preparations and a high-calorie diet rich in proteins and fat. Chronic treatment of cystic fibrosis-related lung disease aims to improve the clearance of the bronchial tree, suppressing chronic bacterial infection and local chronic inflammation. However, no therapy was available to correct the defect in the gene or its product until 2012.The aim was to analyze literature on CFTR modulators, including their efficacy and safety, and assess the potential for developing new modulators to treat cystic fibrosis.Materials. The review included literature data (45 publications) on the use of CFTR modulators and international websites’ data.Results. Since the discovery of the CFTR gene in 1989, more than 2000 mutations or variants of the CFTR gene (hereinafter referred to as genetic variants) have been described. They interfere with the synthesis of the CFTR protein, its transport to the apical membrane of the cell, or disrupt its function as a channel for chloride anions. Although it is currently not possible to completely replace the mutant gene with a normal copy, small molecules have been identified that can modify the mutant CFTR protein and amend its function. The potential therapeutic measures are determined by class of the mutation. In clinical practice, pharmacological modeling of ion transport is currently possible only with the use of CFTR modulators: correctors and potentiators. The review defines these groups of drugs and describes 4 licensed CFTR modulators, including molecules of ivacaftor, lumacaftor, tezacaftor, elexacaftor. The data on the promising emerging next generation modulators and the prospects for the personalized selection of drugs using the assays on intestinal organoids are presented.

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The primary purpose of pulmonary ventilation is to supply oxygen (O2) for sustained aerobic respiration in multicellular organisms. However, a plethora of abiotic insults and airborne pathogens present in the environment are occasionally introduced into the airspaces during inhalation, which could be detrimental to the structural integrity and functioning of the respiratory system. Multiple layers of host defense act in concert to eliminate unwanted constituents from the airspaces. In particular, the mucociliary escalator provides an effective mechanism for the continuous removal of inhaled insults including pathogens. Defects in the functioning of the mucociliary escalator compromise the mucociliary clearance (MCC) of inhaled pathogens, which favors microbial lung infection. Defective MCC is often associated with airway mucoobstruction, increased occurrence of respiratory infections, and progressive decrease in lung function in mucoobstructive lung diseases including cystic fibrosis (CF). In this disease, a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene results in dehydration of the airway surface liquid (ASL) layer. Several mice models of Cftr mutation have been developed; however, none of these models recapitulate human CF-like mucoobstructive lung disease. As an alternative, the Scnn1b transgenic (Scnn1b-Tg+) mouse model overexpressing a transgene encoding sodium channel nonvoltage-gated 1, beta subunit (Scnn1b) in airway club cells is available. The Scnn1b-Tg+ mouse model exhibits airway surface liquid (ASL) dehydration, impaired MCC, increased mucus production, and early spontaneous pulmonary bacterial infections. High morbidity and mortality among mucoobstructive disease patients, high economic and health burden, and lack of scientific understanding of the progression of mucoobstruction warrants in-depth investigation of the cause of mucoobstruction in mucoobstructive disease models. In this review, we will summarize published literature on the Scnn1b-Tg+ mouse and analyze various unanswered questions on the initiation and progression of mucobstruction and bacterial infections.

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Large conductance, calcium- and voltage-activated potassium (BKCa) channels are important modulators of pulmonary vascular smooth muscle membrane potential, and phosphorylation of BKCa channels by protein kinases regulates pulmonary arterial smooth muscle function. However, little is known about the effect of phosphorylating specific channel subunits on BKCa channel activity. The present study was done to determine the effect of mutating protein kinase C (PKC) phosphorylation site serine 1076 (S1076) on transfected human BKCa channel α-subunits in human embryonic kidney (HEK-293) cells, a heterologous expression system devoid of endogenous BKCa channels. Results showed that mutating S1076 altered the effect of PKC activation on BKCa channels in HEK-293 cells. Specifically, the phospho-deficient mutation BKCa-α(S1076A)/β1 attenuated the excitatory effect of the PKC activator phorbol myristate acetate (PMA) on BKCa channels, whereas the phospho-mimetic mutation BKCa-α(S1076E)/β1 increased the excitatory effect of PMA on BKCa channels. In addition, the phospho-null mutation S1076A blocked the activating effect of cGMP-dependent protein kinase G (PKG) on BKCa channels. Collectively, these results suggest that specific putative PKC phosphorylation site(s) on human BKCa channel α-subunits influences BKCa channel activity, which may subsequently alter pulmonary vascular smooth muscle function and tone.

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According to the survey of 214 patients aged between 28 to 75 years (the average age 49 years) with chronic broncho-pulmonary diseases the author identified the informative of the use of medical test of the electro-acupunctural method by Reinhold Voll (EAV) when forming the rehabilitation therapy by using composite homeopathic remedies. The method presented in this study shows the dynamics of the electro-dermal skin conductance measuring at acupoints when choosing a composite homeopathic remedy. When testing homeopathic remedies and in case of compliance of the particular drug with physiological processes or biological information of the patient&#180;s body the resonant response on a EAV device scale is being fixed as a positive medical test. At the same time the pathological changes in electrophysiological measurements such as the «maximum deflection» (MD) and the «range of return arrow» (RRA) return to relative range of physiological norm. In the study we introduce the research on objectification of the selection of homeopathic remedies and optimization of the recommended amount of complex homeopathic remedies in the patients with respiratory system diseases. The diagnostic results of the electro-acupunctural method by Reinhold Voll obtained in this study allow to forming tactics of the therapy using composite homeopathic remedies in the rehabilitation treatment of patients with chronic lung disease.

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Defects in the innate immune system in the lung with attendant bacterial infections contribute to lung tissue damage, respiratory insufficiency, and ultimately death in the pathogenesis of cystic fibrosis (CF). Professional phagocytes, including alveolar macrophages (AMs), have specialized pathways that ensure efficient killing of pathogens in phagosomes. Phagosomal acidification facilitates the optimal functioning of degradative enzymes, ultimately contributing to bacterial killing. Generation of low organellar pH is primarily driven by the V-ATPases, proton pumps that use cytoplasmic ATP to load H+ into the organelle. Critical to phagosomal acidification are various channels derived from the plasma membrane, including the anion channel cystic fibrosis transmembrane conductance regulator, which shunt the transmembrane potential generated by movement of protons. Here we show that the transient receptor potential canonical-6 (TRPC6) calcium-permeable channel in the AM also functions to shunt the transmembrane potential generated by proton pumping and is capable of restoring microbicidal function to compromised AMs in CF and enhancement of function in non-CF cells. TRPC6 channel activity is enhanced via translocation to the cell surface (and then ultimately to the phagosome during phagocytosis) in response to G-protein signaling activated by the small molecule (R)-roscovitine and its derivatives. These data show that enhancing vesicular insertion of the TRPC6 channel to the plasma membrane may represent a general mechanism for restoring phagosome activity in conditions, where it is lost or impaired.

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Background. In the international clinical practice there have been occasional reports of phenylketonuria (PKU) and cystic fibrosis (CF) found simultaneously in the same patient. Both PKU and CF are the inherited disorders characterized by autosomal recessive type of inheritance. Currently the combination of two or more inherited disorders in one patient is considered to be a clinical rarity.Case description. This is a clinical case of two genetic disorders, CF and PKU, combined in a 5-year old patient who had been followed up since birth. Owing to implementation of neonatal screening for inherited and congenital diseases into clinical practice, during the first month of life the infant was diagnosed with CF (diagnostically significant elevation of immunoreactive trypsin [IRT] at the initial [163.2 ng/mL] and repeat testing on day 21 of life [138.7 ng/mL]) and PKU (phenylalanine [PA] level 15.9 mg/dL). Both disorders have been confirmed by genetic tests, i.e., hom*ozygous DelF508 mutation was found in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and P281L mutation in the phenylalanine hydroxylase (PAH) gene was also present in hom*ozygous state. Child’s parents strictly adhered to dietary and treatment recommendations. By the age of 5 years the child developed symptoms of neurological disorder and disorder of the respiratory system, cognitive impairment and delay in speech development, subclinical epileptiform activity with high risk of epilepsy, and chronic inflammation of the respiratory tract.Conclusion. This case report demonstrates the important role of neonatal screening in early diagnosis and timely start of therapy, and underscores the importance of continuous medication in such genetic disorders as CF and PKU. On the whole, such approach brings about a relative preservation of functioning of the most affected organs and systems. By the age of 5 years the child does not form bronchiectases, shows no signs of chronic hypoxia, nutritional deficiency or pronounced neurologic deficit, and is at low risk for the development of autism spectrum disorder. At the same time, the larger scale and longer-term observations are required in order to make the unequivocal conclusions about the prognosis of these diseases under conditions of modern-day medical follow-up.

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Background. In the international clinical practice there have been occasional reports of phenylketonuria (PKU) and cystic fibrosis (CF) found simultaneously in the same patient. Both PKU and CF are the inherited disorders characterized by autosomal recessive type of inheritance. Currently the combination of two or more inherited disorders in one patient is considered to be a clinical rarity.Case description. This is a clinical case of two genetic disorders, CF and PKU, combined in a 5-year old patient who had been followed up since birth. Owing to implementation of neonatal screening for inherited and congenital diseases into clinical practice, during the first month of life the infant was diagnosed with CF (diagnostically significant elevation of immunoreactive trypsin [IRT] at the initial [163.2 ng/mL] and repeat testing on day 21 of life [138.7 ng/mL]) and PKU (phenylalanine [PA] level 15.9 mg/dL). Both disorders have been confirmed by genetic tests, i.e., hom*ozygous DelF508 mutation was found in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and P281L mutation in the phenylalanine hydroxylase (PAH) gene was also present in hom*ozygous state. Child’s parents strictly adhered to dietary and treatment recommendations. By the age of 5 years the child developed symptoms of neurological disorder and disorder of the respiratory system, cognitive impairment and delay in speech development, subclinical epileptiform activity with high risk of epilepsy, and chronic inflammation of the respiratory tract.Conclusion. This case report demonstrates the important role of neonatal screening in early diagnosis and timely start of therapy, and underscores the importance of continuous medication in such genetic disorders as CF and PKU. On the whole, such approach brings about a relative preservation of functioning of the most affected organs and systems. By the age of 5 years the child does not form bronchiectases, shows no signs of chronic hypoxia, nutritional deficiency or pronounced neurologic deficit, and is at low risk for the development of autism spectrum disorder. At the same time, the larger scale and longer-term observations are required in order to make the unequivocal conclusions about the prognosis of these diseases under conditions of modern-day medical follow-up.