Gas Exchange Function Research Articles

Leaf porous structure Inspired packaging film for fruits preservation and monitoring CO2 concentration of package

The preservation of fresh fruit and vegetables is always a challenge. Equilibrium modified atmosphere packaging (EMAP) is ideal for preserving fresh produce. The gas transmission and selectivity of EMAP films is crucial for achieving atmospheric equilibrium in packaging. Inspired by leaf porous structure regulating their gas exchange function, we selected natural porous diatomite as the gas channel and modified it with polyethyleneimine (PEI). By introducing diatomite into the film matrix of CNFs, the gas transmission and CO2/O2 selectivity of EMAP films were regulated. The atmosphere in all the packages of EMAP films reached equilibrium within 24 h, which kept the fruit in low intensity aerobic respiration. The EMAP film of DgP7.5 (O2 transmission rate 43.33 cc m−2 day−1 bar−1, CO2/O2 selectivity 1.56) was found to be the most suitable for packaging litchis and green plums. Diatomite with porous structures will provide a design concept for EMAP films.

Oxygenation index and NT-proBNP as predictors of pulmonary hypertension and ventilation/perfusion mismatch in acute pulmonary embolism.

The magnitude of pulmonary artery pressure (PAP) and the extent of ventilation/perfusion (V/Q) mismatch are essential for assessing the prognosis of acute pulmonary embolism (APE). We aimed to develop a model for predicting the status of the pulmonary circulation and arterial gas exchange functions using serum levels of cardiac biomarkers and arterial oxygenation index (OI) values. This single-center, retrospective observational cohort study included 224 patients with APE. Multivariate linear regression and Poisson regression were used to test the statistical association between cardiac biomarkers, OI, PAP, and V/Q mismatch. Diagnostic efficiency was calculated from a receiver operating characteristic (ROC) curve. Serum levels of troponin I (TNI), N-terminal pro-brain natriuretic peptide (NT-proBNP), and arterial OI magnitude significantly correlated with PAP and V/Q mismatches (P < 0.05). Multivariate linear regression showed that NT-proBNP serum levels (β = 0.002, P < 0.001) and OI values (β = -0.022, P = 0.001) significantly influenced PAP. Arterial OI (β = -0.039, P < 0.001) had a significant influence on the percentage of pulmonary vascular obstruction (PVO) as determined by perfusion scanning. Poisson regression showed that OI (odds ratio: 0.995, p < 0.001) was a predictor of the number of lung segments with V/Q mismatches. ROC area under the curve (AUC) values of NT-proBNP and OI predicting pulmonary hypertension were 0.716 and 0.730, respectively, and for V/Q mismatch scanning, the results were 0.601 and 0.634, respectively. Arterial OI and serum levels of cardiac biomarkers may be used as indicators of pulmonary hypertension and V/Q mismatch.

C-JUN-mediated transcriptional responses in lymphatic endothelial cells are required for lung fluid clearance at birth

Fluid clearance mediated by lymphatic vessels is known to be essential for lung inflation and gas-exchange function during the transition from prenatal to postnatal life, yet the molecular mechanisms that regulate lymphatic function remain unclear. Here, we profiled the molecular features of lymphatic endothelial cells (LECs) in embryonic and postnatal day (P) 0 lungs by single-cell RNA-sequencing analysis. We identified that the expression of c-JUN is transiently upregulated in P0 LECs. Conditional knockout of Jun in LECs impairs the opening of lung lymphatic vessels at birth, leading to fluid retention in the lungs and neonatal death. We further demonstrated that increased mechanical pressure induces the expression of c-JUN in LECs. c-JUN regulates the opening of lymphatic vessels by modulating the remodeling of the actin cytoskeleton in LECs. Our study established the essential regulatory function of c-JUN-mediated transcriptional responses in facilitating lung lymphatic fluid clearance at birth.

САРКОИДОЗ И COVID-19: ОПЫТ ФГБНУ «ЦНИИТ»

Our objective was to study the impact of prior sarcoidosis treatment and past COVID-19 on the course of sarcoidosis in patients hospitalized in the Central TB Research Institute. The study enrolled 60 sarcoidosis patients with past COVID-19. We studied case records, clinical manifestations of sarcoidosis and COVID-19, X-ray images, gas exchange function tests. Pulmonary sarcoidosis and sarcoidosis of intrathoracic lymph nodes (ITLN) without involvement of other organs or systems prevailed. The severity of COVID-19 significantly varied, though we did not reveal any correlation between the clinical and radiological patterns of sarcoidosis and the severity of viral lung disease. Exacerbation of sarcoidosis was observed in 27 patients (45%), though without involvement of other organs or systems. We did not detect any significant decrease in diffusing capacity of the lungs or partial pressure of oxygen in arterial blood in sarcoidosis patients after COVID-19. Fifty-two patients (38%) with chronic sarcoidosis continued therapy with systemic glucocorticosteroids (SGCS) during the COVID-19 disease, the stable course of sarcoidosis was observed during one year after COVID-19. The share of patients who did not receive SGCS due to COVID-19 without subsequent exacerbation of sarcoidosis was only 25.64%. The onset of sarcoidosis within one year after COVID-19 was observed in 12 out of 60 patients (20%).

D-Dimer Sebagai Salah Satu Parameter Perbaikan Klinis pada Kasus Covid-19 Gejala Berat

Background. Coronavirus Disease 2019 (COVID-19) has been a global pandemic since March 2020. The number of patients is massive and clinical symptoms vary from mild to severe symptoms. Several laboratory results showed abnormal values in Covid-19 patients, including an increase in the value of D-dimer. Elevated levels of D-dimer in COVID-19 patients are strongly associated with severity and increased mortality. We report a case of a severe symptomatic COVID-19 patient with high D dimer levels at the start of treatment and showing clinical improvement according to a decrease in D dimer levels. Methods. We treat and follow the clinical and laboratory developments of COVID-19 patients with severe symptoms from the time they enter the Intensive Care Unit (ICU) until they move to a regular ward. Results. A 53-year-old male patient diagnosed with viral pneumonia et causa covid-19 was admitted to the ICU with severe symptoms and high initial d-dimer levels (1,413 ug/ml). The patient received ventilator assistance and standard therapy according to the Covid 19 management protocol of the Ministry of Health of the Republic of Indonesia. Anticoagulation using heparin intravenously with a dose adjusted to the level of d dimer, aPTT, and clinical condition of the patient who is monitored regularly. The trend of d dimers decreased parallel to the decrease in C reactive protein (CRP) levels, increased lung gas exchange function was evaluated from the PaO2/Fio2 ratio (PF ratio) and the clinical improvement of the patients. Conclusion. D-dimer is closely related to the severity of covid 19 patients. D dimer can be used as one of the parameters of patient clinical improvement.

Experience of extracorporeal membrane oxygenation in a laboring woman with severe preeclampsia

Introduction. Hypertensive disorders during pregnancy are one of the main causes of maternal mortality in the world. Both premature detachment of the normally located placenta, which led to massive bleeding on the background of placental insufficiency, according to the theory of placental ischemia, and disruption of compensatory mechanisms, leading to multiple organ failure, can lead to an unfavorable outcome. The pathogenesis of lung damage in preeclampsia is based on the activation of lipid peroxidation. Therefore, one of the components of complex therapy of severe lung damage may be the use of venovenous extracorporeal membrane oxygenation (ECMO), which is a method of extracorporeal support of gas exchange function in patients with life-threatening acute respiratory failure, accompanied by severe arterial hypoxemia and hypercapnia. The aim of the work is to demonstrate the possibility of using extracorporeal membrane oxygenation in the complex therapy of severe lung damage in a patient with multiple organ failure caused by severe preeclampsia. Materials and methods. A clinical observation of the nature of the course of multiple organ failure and lung damage in a laboring woman with severe preeclampsia is presented, her life history, diseases, diagnostic and treatment methods used are analyzed. Results and discussion. The described clinical case demonstrates the possibility of successful application of extracorporeal membrane oxygenation in combination with early renal replacement therapy, respiratory therapy and nutritional support in a patient with severe lung damage against the background of multiple organ failure caused by severe preeclampsia. Conclusion. It is necessary to use extracorporeal replacement techniques of vital functions replacement as early as possible in patients with severe lung damage against the background of multiple organ failure caused by severe preeclampsia.

A method for quantitation of apoplast hydration in Arabidopsis leaves reveals water-soaking activity of effectors of Pseudomonas syringae during biotrophy

The plant apoplast has a crucial role in photosynthesis and respiration due to its vital function in gas exchange and transpiration. The apoplast is also a dynamic environment that participates in many ion and nutrient transport processes via plasma membrane-localized proteins. Furthermore, diverse microbes colonize the plant apoplast, including the hemibiotrophic bacterial pathogen, Pseudomonas syringae pv. tomato (Pto) strain DC3000. Pto DC3000 initiates pathogenesis upon moving through stomata into the apoplast and then proliferating to high levels. Here we developed a centrifugation-based method to isolate and quantify the apoplast fluid in Arabidopsis leaves, without significantly damaging the tissue. We applied the simple apoplast extraction method to demonstrate that the Pto DC3000 type III bacterial effectors AvrE1 and HopM1 induce hydration of the Arabidopsis apoplast in advance of macroscopic water-soaking, disruption of host cell integrity, and disease progression. Finally, we demonstrate the utility of the apoplast extraction method for isolation of bacteria proliferating in the apoplast.

Functional disorders of the respiratory system after a new coronavirus infection COVID-19

COVID-19 (Coronavirus disease 2019) is an infectious disease caused by the coronavirus SARS-CoV-2, characterized by a high level of morbidity and mortality. A new coronavirus infection affects all organs and systems and often occurs with lung damage and respiratory failure. In a significant part of patients after the acute period of COVID-19, the symptoms of the disease persist, but the most problematic symptoms are the ones regarding lung damage that persists for a long amount of time.&#x0D; This review summarizes the results of our research in 20202021. The purpose of the conducted studies was to estimate the functional parameters of the respiratory system in patients that have been infected by COVID-19. Along with conventional pulmonary function tests (spirometry, body plethysmography and diffusion test), impulse oscillometry, the multiple-breath nitrogen washout test, determination of the maximum inspiratory and expiratory pressures were performed in all patients. Thus, we evaluated the ventilation and gas exchange function of the bronchopulmonary system, the functional state of the peripheral parts of the lungs, including the small airways, the uniformity of pulmonary ventilation and the strength of the respiratory muscles in different periods of recovery after COVID-19, including the follow-up after medical rehabilitation.&#x0D; To sum up, comprehensive functional assessment of the respiratory system is an important clinical tool that allows the planning of pharmacotherapy and to create individual programs of medical rehabilitation of patients who had COVID-19.

Evaluation and clinical significance of gas exchange in patients with acute respiratory distress syndrome

Gas exchange abnormalities is the pathophysiology characteristic of acute respiratory distress syndrome (ARDS). The severity of gas exchange abnormalities not only reflect the severity and outcome of the disease, but could also be an important index to guide individual mechanical ventilation settings and evaluate the therapeutic effects of inhaled vasodilator. The common techniques to measure gas exchange include multiple inert gas elimination technique, automatic lung parameter estimator, electrical impedance tomography, and single-photon emission CT. Nowadays, bedside techniques and measurements for improving gas exchange function in ARDS patients are still limited. Therefore, the improvement and promotion of bedside real-time gas exchange monitoring technology may achieve the goal of personalized medicine in ARDS. This article reviewed the common evaluation methods of gas exchange function in ARDS and their significance, in order to pay more attention to the evaluation of gas exchange function and further improve the prognosis of patients with ARDS.

Comparative analysis of the mineral composition of the&#x0D; leukocyte, erythrocyte fraction and PRP plasma in patients with bisphosphonate osteonecrosis of the jaw bones

A complication of the use of bisphosphonate drugs is the development of bisphosphonate osteonecrosis. There is not enough information about the state of the microelement composition of the blood and the dynamics of metabolic processes for various bisphosphonate drugs. There are 184 patients under observation for bisphosphonate osteonecrosis of the jaw bones. The mineral components of three blood fractions were monitored: sulfur (S2-), chlorine (Cl-), potassium (K+), calcium (Ca2+), phosphorus (P3+) at the preoperative and postoperative stages. At the preoperative stage, the negative dynamics of indicators of bone metabolites (Ca2+ and P3+) contributed to the development of osteomalacia, followed by a jaw fracture due to local loads. Hypercalcemia developed against the background of acidosis in the bone tissue (Ca2+ ions were replaced by H+ ions, with partial diffusion into the liquid fraction, due to disorganization of the synthesis of chondroitinsulfuric acid). Hyperphosphatemia is due to the pharmacokinetics of bisphosphonate drugs. Violation of the metabolism of sulfur-containing amino acids leads to the accumulation of S2- in blood fractions. The decrease in Cl- is due to metabolic acidosis against the background of an atrabiliary gas exchange function of erythrocytes, which enhances the pathological focus of tissues with the migration of Cl- to the lesion. A decrease in K+ was noted against the background of severe muscle atony. The dynamics of the studied parameters correlates with the clinical picture of bisphosphonate osteonecrosis. The trace element composition of blood fractions, starting from the 7th day of the postoperative period, was characterized by a trend towards positive dynamics. With further observation at the 3rd and 6th months, the content of the studied trace elements in the reference values. The clinical picture corresponds to the scope and timing of surgery in 100% of patients.

Modeling lung diseases using reversibly immortalized mouse pulmonary alveolar type 2 cells (imPAC2)

BackgroundA healthy alveolar epithelium is critical to the gas exchange function of the lungs. As the major cell type of alveolar epithelium, alveolar type 2 (AT2) cells play a critical role in maintaining pulmonary homeostasis by serving as alveolar progenitors during lung injury, inflammation, and repair. Dysregulation of AT2 cells may lead to the development of acute and chronic lung diseases and cancer. The lack of clinically relevant AT2 cell models hampers our ability to understand pulmonary diseases. Here, we sought to establish reversibly immortalized mouse pulmonary alveolar type 2 cells (imPAC2) and investigate their potential in forming alveolar organoids to model pulmonary diseases.MethodsPrimary mouse pulmonary alveolar cells (mPACs) were isolated and immortalized with a retroviral expression of SV40 Large T antigen (LTA). Cell proliferation and survival was assessed by crystal violet staining and WST-1 assays. Marker gene expression was assessed by qPCR, Western blotting, and/or immunostaining. Alveolar organoids were generated by using matrigel. Ad-TGF-β1 was used to transiently express TGF-β1. Stable silencing β-catenin or overexpression of mutant KRAS and TP53 was accomplished by using retroviral vectors. Subcutaneous cell implantations were carried out in athymic nude mice. The retrieved tissue masses were subjected to H & E histologic evaluation.ResultsWe immortalized primary mPACs with SV40 LTA to yield the imPACs that were non-tumorigenic and maintained long-term proliferative activity that was reversible by FLP-mediated removal of SV40 LTA. The EpCAM+ AT2-enriched subpopulation (i.e., imPAC2) was sorted out from the imPACs, and was shown to express AT2 markers and form alveolar organoids. Functionally, silencing β-catenin decreased the expression of AT2 markers in imPAC2 cells, while TGF-β1 induced fibrosis-like response by regulating the expression of epithelial-mesenchymal transition markers in the imPAC2 cells. Lastly, concurrent expression of oncogenic KRAS and mutant TP53 rendered the imPAC2 cells a tumor-like phenotype and activated lung cancer-associated pathways. Collectively, our results suggest that the imPAC2 cells may faithfully represent AT2 populations that can be further explored to model pulmonary diseases.

217.9: Activation of Angiotensin-converting Enzyme 2 (ACE2) Modulates Lung Mechanics in a Brain Death Model and Attenuates Pulmonary Edema After Rat Lung Transplantation

Introduction: Lung transplantation is a therapeutic option established worldwide for end-stage lung diseases. However, as most donors evolve with brain death (BD), the donated lung may have been compromised. In view of the participation of the renin angiotensin system (RAS) and the use of angiotensin-converting enzyme 2 (ACE2) activators in several pathological processes, it was investigated how diminazene aceturate (DIZE), an ACE2 activator, modulates hemodynamic and blood gas changes, as well as lung function following transplantation in rats. Method: Male Lewis rats were randomly distributed in the following experimental groups: intact, brain death (BD) and BD + diminazene aceturate (BD+DIZE). The last two groups were submitted to brain death process, treated with saline (0.9%) or DIZE (15 mg/kg-1) and kept on mechanical ventilation for 6 hours (donor). After this period, cardiopulmonary block extraction and left unilateral transplantation (LTx) with independent graft ventilation was performed, followed by 2h reperfusion. Hemodynamics (mean arterial pressure - MAP), blood gas analysis, lung mechanics, and pulmonary edema were evaluated. Results are presented as S.E.M. (ANOVA; Tukey; p<0.05). (Approval # CEUA/FMUSP - 1630/2021). Results: The administration of DIZE, 3 hours after BD, prevented the increase in the MAP (210’ after BD-induction: BD – 110 ± 12 mmHg; n=5; BD+DIZE – 40 ± 12 mmHg; n=4/ p=0.0001) without associated blood gas and metabolic alterations. Changes in lung mechanics, such as decreased tissue damping (G) and histeresivity (n) followed by increased respiratory system compliance (Crs), were associated with BD+DIZE (G - 0,25 ± 0,03 cmH2O/mL; Crs - 0,71 ± 0,03 mL/cmH2O; n – 0,14 ± 0,008) compared to intact (G - 0,40 ± 0,02 cmH2O/mL, p = 0.01; Crs – 0,64 ± 0,01 mL/cmH2O, p = 0.02; n - 0,26 ± 0,01, p = 0.004) and BD groups (G – 0,41± 0,05 cmH2O/mL, p = 0.02; Crs – 0,61 ± 0,01 mL/cmH2O, p = 0.01; n - 0,25 ± 0,008, p = 0.01) (Figure 1). After LTx, MAP, gas exchange function, and lung mechanical parameters, were not different among the 3 groups (p>0.05). On the other hand, the DIZE treatment was capable to reduce wet-to-dry weight ratio (INTACT – 1,87 ± 0,13; BD – 2,59 ± 0,14; BD+DIZE – 1,93 ± 0,15/ p=0.01) (Figure 2). Conclusion: Our data suggests that activation of ACE2 is able to modulate donor hemodynamic and lung mechanical parameters, probably reducing tissue resistance and improving airflow in the peripheral airways, converging to a decrease in ventilation heterogeneity in the sudden onset model of brain death. Our data also indicates that DIZE attenuates pulmonary edema on grafts from BD donors after lung transplantation. Keywords: Diminazene aceturate. Renin-angiotensin system. Brain death. Lung mechanics. Lung transplantation.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico.

Induction of severe hypoxemia and low lung recruitability for the evaluation of therapeutic ventilation strategies: a translational model of combined surfactant-depletion and ventilator-induced lung injury

BackgroundModels of hypoxemic lung injury caused by lavage-induced pulmonary surfactant depletion are prone to prompt recovery of blood oxygenation following recruitment maneuvers and have limited translational validity. We hypothesized that addition of injurious ventilation following surfactant-depletion creates a model of the acute respiratory distress syndrome (ARDS) with persistently low recruitability and higher levels of titrated “best” positive end-expiratory pressure (PEEP) during protective ventilation.MethodsTwo types of porcine lung injury were induced by lung lavage and 3 h of either protective or injurious ventilation, followed by 3 h of protective ventilation (N = 6 per group). Recruitment maneuvers (RM) and decremental PEEP trials comparing oxygenation versus dynamic compliance were performed after lavage and at 3 h intervals of ventilation. Pulmonary gas exchange function, respiratory mechanics, and ventilator-derived parameters were assessed after each RM to map the course of injury severity and recruitability.ResultsLung lavage impaired respiratory system compliance (Crs) and produced arterial oxygen tensions (PaO2) of 84±13 and 80±15 (FIO2 = 1.0) with prompt increase after RM to 270–395 mmHg in both groups. After subsequent 3 h of either protective or injurious ventilation, PaO2/FIO2 was 104±26 vs. 154±123 and increased to 369±132 vs. 167±87 mmHg in response to RM, respectively. After additional 3 h of protective ventilation, PaO2/FIO2 was 120±15 vs. 128±37 and increased to 470±68 vs. 185±129 mmHg in response to RM, respectively. Subsequently, decremental PEEP titration revealed that Crs peaked at 36 ± 10 vs. 25 ± 5 ml/cm H2O with PEEP of 12 vs. 16 cmH2O, and PaO2/FIO2 peaked at 563 ± 83 vs. 334 ± 148 mm Hg with PEEP of 16 vs. 22 cmH2O in the protective vs. injurious ventilation groups, respectively. The large disparity of recruitability between groups was not reflected in the Crs nor the magnitude of mechanical power present after injurious ventilation, once protective ventilation was resumed.ConclusionAddition of transitory injurious ventilation after lung lavage causes prolonged acute lung injury with diffuse alveolar damage and low recruitability yielding high titrated PEEP levels. Mimicking lung mechanical and functional characteristics of ARDS, this porcine model rectifies the constraints of single-hit lavage models and may enhance the translation of experimental research on mechanical ventilation strategies.

Normothermic &lt;i&gt;ex vivo&lt;/i&gt; perfusion of isolated lungs in an experiment using a russian-made perfusion system

According to global health statistics, respiratory diseases, together with infectious complications and hereditary lung diseases, rank as the third leading cause of death. Today, lung transplantation (LTx) is a well-recognized modality of treatment for end-stage chronic lung disease. However, the number of LTx surgeries performed is much lower than other solid organs. This is due to the high requirements for the potential donor and characteristics of the lung graft, reflecting the efficiency of gas exchange function. Non-compliance with the selection criteria leads to deselection of donors, which, according to various estimates, occurs in 80–85% of cases. One of the ways to increase the number of lung transplant surgeries is to restore them to the level of optimal gas exchange parameters, which can be achieved and objectively assessed during normothermic ex vivo lung perfusion (EVLP). EVLP is becoming increasingly common at leading transplantation centers in Europe and North America. This has significantly increased the number of transplant surgeries as a result of using lungs procured from suboptimal donors and rehabilitated via EVLP. In our pilot study, the developed Russian-made mechanical circulatory support system showed that performing normothermic EVLP for isolated lungs under experimental conditions is feasible. Basic and optimized perfusion protocols have fully shown that they are reliable and efficient.

Administration of Drugs/Gene Products to the Respiratory System: A Historical Perspective of the Use of Inert Liquids.

The present review is a historical perspective of methodology and applications using inert liquids for respiratory support and as a vehicle to deliver biological agents to the respiratory system. As such, the background of using oxygenated inert liquids (considered a drug when used in the lungs) opposed to an oxygen-nitrogen gas mixture for respiratory support is presented. The properties of these inert liquids and the mechanisms of gas exchange and lung function alterations using this technology are described. In addition, published preclinical and clinical trial results are discussed with respect to treatment modalities for respiratory diseases. Finally, this forward-looking review provides a comprehensive overview of potential methods for administration of drugs/gene products to the respiratory system and potential biomedical applications.

Steroid-induced fibroblast growth factors drive an epithelial-mesenchymal inflammatory axis in severe asthma.

Asthma and inflammatory airway diseases restrict airflow in the lung, compromising gas exchange and lung function. Inhaled corticosteroids (ICSs) can reduce inflammation, control symptoms, and improve lung function; however, a growing number of patients with severe asthma do not benefit from ICS. Using bronchial airway epithelial brushings from patients with severe asthma or primary human cells, we delineated a corticosteroid-driven fibroblast growth factor (FGF)-dependent inflammatory axis, with FGF-responsive fibroblasts promoting downstream granulocyte colony-stimulating factor (G-CSF) production, hyaluronan secretion, and neutrophilic inflammation. Allergen challenge studies in mice demonstrate that the ICS, fluticasone propionate, inhibited type 2-driven eosinophilia but induced a concomitant increase in FGFs, G-CSF, hyaluronan, and neutrophil infiltration. We developed a model of steroid-induced neutrophilic inflammation mediated, in part, by induction of an FGF-dependent epithelial-mesenchymal axis, which may explain why some individuals do not benefit from ICS. In further proof-of-concept experiments, we found that combination therapy with pan-FGF receptor inhibitors and corticosteroids prevented both eosinophilic and steroid-induced neutrophilic inflammation. Together, these results establish FGFs as therapeutic targets for severe asthma patients who do not benefit from ICS.

Neonatal Immune Responses to Respiratory Viruses.

Respiratory tract infections are a leading cause of morbidity and mortality in newborns, infants, and young children. These early life infections present a formidable immunologic challenge with a number of possibly conflicting goals: simultaneously eliminate the acute pathogen, preserve the primary gas-exchange function of the lung parenchyma in a developing lung, and limit long-term sequelae of both the infection and the inflammatory response. The latter has been most well studied in the context of childhood asthma, where multiple epidemiologic studies have linked early life viral infection with subsequent bronchospasm. This review will focus on the clinical relevance of respiratory syncytial virus (RSV), human metapneumovirus (HMPV), and rhinovirus (RV) and examine the protective and pathogenic host responses within the neonate.

On the question of studying hyperoxic sanogenesis SARS-CoV-2-associated pneumonia

The article is devoted to the analysis of literature data on the use of hyperbaric oxygenation (HBO) in patients with COVID-19, complicated by the development of SARS-CoV-2-associated pneumonia to build a hypothesis about possible mechanisms of therapeutic action of hyperbaric oxygen (HBO2) in this pathology. The expediency of using «soft» (1.3–2.0 attacks, 40–60 min) HBO modes in SARS-CoV-2-associated pneumonia is substantiated. Several possible mechanisms of elimination of HBO2 violation of lung gas exchange function in SARS-CoV-2-associated pneumonia are considered. Firstly, hyperoxic stimulation of diaphragm contraction. Secondly, the inhibitory effect of HBO2 on the development of interstitial and alveolar edema in the lungs. Thirdly, elimination of HBO2 stimulating effect of thrombin and fibrinogen on contractility of pulmonary capillary endotheliocytes. Fourth, regulation of HBO2 metabolism of fibronectin, thromboplastin, von Willibrant factors, and platelet activation factor in the wall of pulmonary capillaries. As a result, its thrombogenic activity increases in this pathology.

Erythrocyte lysis and angle-resolved light scattering measured by scanning flow cytometry result to 48 indices quantifying a gas exchange function of the human organism.

Molecular/cell level of gas exchange function assumes the accurate measurement of erythrocyte characteristics and rate constants concerning to molecules involved into the CO2 /O2 transport. Unfortunately, common hematology analyzers provide the measurement of eight indices of erythrocytes only and say little about erythrocyte morphology and nothing about rate constants of cellular function. The aim of this study is to demonstrate the ability of the Scanning Flow Cytometer (SFC) in the complete morphological analysis of mature erythrocytes and characterization of erythrocyte function via measurement of lysing kinetics. With this study we are introducing 48 erythrocyte indices. To provide the usability of application of the SFC in clinical diagnosis, we formed four categories of indices which are as follows: content/concentration (9 indices), morphology (26 indices), age (5 indices), and function (8 indices). The erythrocytes of 39 healthy volunteers were analyzed with the SFC to fix the first-ever reference intervals for the new indices introduced. The essential measurable reliability of the presented method is expressed in terms of errors of characteristics of single erythrocytes retrieved from the solution of the inverse light-scattering problem and errors of parameters retrieved from the fitting of the experimental kinetics by molecular-kinetics model of erythrocyte lysis.

A model of the pulmonary acinar circulatory system with gas exchange function to explore the influence of alveolar diameter

Lung diseases such as acute respiratory distress syndrome affect the patient's lung compliance, which in turn affects the ability of gas exchange. Changes in alveolar diameter relate to local lung compliance. How alveolar diameter affects gas exchange, particularly oxygen concentrations in alveolar capillaries, is a topic of concern for researchers, and can be studied using mathematical models. The level of small-scale mathematical models of the pulmonary circulatory system was the alveolar capillaries, but existing models do not consider the gas-exchange function and fail to reflect the influence of alveolar diameter. Therefore, we proposed a pulmonary acinar capillary model with gas exchange function, and most importantly, introduced alveolar diameter into the model, to analyze the effect of alveolar diameter on the gas exchange function of the pulmonary acini. The model was tested by three respiratory function simulation experiments. According to the simulation results of changing diameter, we found that the alveolar diameter mainly affects the alveolar gas exchange function of lung acinar inlets and the middle section compared with the peripheral section.