Involvement of Muscarinic M3 Receptor in the Development of M2 Macrophages in Allergic Inflammation.

INTRODUCTION: The muscarinic M3 receptor antagonist, tiotropium, has a bronchodilatory effect on asthma patients. Additionally, tiotropium inhibits allergic airway inflammation and remodeling in a murine asthma model. However, the underlying mechanisms of this M3 receptor antagonist remain unclear. Therefore, we investigated the effect of muscarinic M3 receptor blockage on M2 macrophage development during allergic airway inflammation. METHODS: BALB/c mice were sensitized and challenged with ovalbumin to develop a murine model of allergic airway inflammation mimicking human atopic asthma. During the challenge phase, mice were treated with or without tiotropium. Lung cells were isolated 24 h after the last treatment and gated using CD68-positive cells. Relm-α and Arginase-1 (Arg1) (M2 macrophage markers) expression was determined by flow cytometry. Mouse bone marrow mononuclear cell-derived macrophages (mBMMacs) and human peripheral blood mononuclear cells (PBMCs)-derived macrophages were stimulated with IL-4 and treated with a muscarinic M3 receptor antagonist in vitro. RESULTS: The total cells, eosinophils, and IL-5 and IL-13 levels in BAL fluids were markedly decreased in the asthma group treated with tiotropium compared to that in the untreated asthma group. The Relm-α and Arg1 expression in macrophages was reduced considerably in the asthma group treated with tiotropium compared to that in the untreated asthma group, suggesting that the development of M2 macrophages was inhibited by muscarinic M3 receptor blockage. Additionally, muscarinic M3 receptor blockage in vitro significantly inhibited M2 macrophage development in both mBMMacs- and PBMCs-derived macrophages. CONCLUSIONS: Muscarinic M3 receptor blockage inhibits M2 macrophage development and prevents allergic airway inflammation. Moreover, muscarinic M3 receptors might be involved in the differentiation of immature macrophages into M2 macrophages.

Risk factors for interstitial lung disease in patients with non-small cell lung cancer with epidermal growth factor receptor-tyrosine kinase inhibitors: A systematic review and meta-analysis.

BACKGROUND: The use of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) can potentially result in interstitial lung disease (ILD), which can substantially impact a patient's quality of life, subsequently leading to the interruption or discontinuation of EGRF-TKI treatment. Clinicians, therefore, need to thoroughly assess patients to determine if they are at risk for ILD. METHODS: We searched for observational study in the following databases: MEDLINE via the PubMed, CENTRAL, and IchushiWeb. The primary outcome was risk factors for the development of ILD, while the secondary outcome was risk factors for the severity of ILD. Of the 1602 studies returned, we selected 11 for meta-analysis, performed using a random-effects model. RESULTS: Risk factors for developing ILD were sex (odds ratio (OR), 1.87; 95% confidence interval (CI), 1.08-3.22; I2 = 0%; P = 0.02), smoking history (OR, 2.13; 95% CI, 1.51-3.00; I2 = 3 4%; P = 0.0001), and history of ILD (OR = 5.95; 95% CI, 3.34-10.59; I2 = 67%; P = 0.0009). Age, previous thoracic surgery or radiotherapy, performance status, histological type of lung cancer, and treatment line were not statistically significant risk factors for ILD. Risk factors identified in one study were serum albumin level, history of nivolumab use, radiographic residual lung volume, and history of pulmonary infection. CONCLUSIONS: We identified risk factors for developing ILD in patients with non-small cell lung cancer treated with EGFR-TKIs.

Surveys of eleven species of wild and zoo birds and feeding experiments in white-tailed eagles reveal differences in the composition of the avian gut microbiome based on dietary habits between and within species.

The composition of the gut microbiome varies due to dietary habits. We investigated influences of diet on the composition of the gut microbiome using the feces of 11 avian species, which consumed grain-, fish- and meat-based diets. We analyzed gut microbiome diversity and composition by next-generation sequencing (NGS) of 16S ribosomal RNA. The grain-diet group had higher gut microbiome diversity than the meat- and fish-diet group. The ratio of Bacteroidetes and Firmicutes phyla was higher in the grain-diet group than in the meat- and fish-diet groups. The grain-diet group had a higher ratio of Veillonellaceae than the meat-diet group and a higher ratio of Eubacteriaceae than the fish-diet habit group. To clarify the influence of diet within the same species, white-tailed eagles (Haliaeetus albicilla, n=6) were divided into two groups, and given only deer meat or fish for approximately one month. The composition of the gut microbiome of individuals in both groups were analyzed by NGS. There were indications of fluctuation in the levels of some bacteria (Lactobacillus, Coriobacteriales, etc.) in each diet group. Moreover, one individual for each group which switched each diet in last week changed to each feature of composition of bacterial flora. The above results show that the composition of the gut microbiome differ depending on diet, even within the same species.

Prevalence and Impact of Social Frailty in Patients with Chronic Obstructive Pulmonary Disease.

Background: Patients with chronic obstructive pulmonary disease (COPD) are more inclined to have a high level of social vulnerability due to their physical and psychological burden. However, to date, there have been no study on social frailty in patients with COPD. This study aimed to investigate the prevalence, characteristics, and impact of social frailty in patients with COPD. Methods: Social frailty was assessed using five items in a questionnaire. A patient was diagnosed with social frailty if responses to two or more items were positive. Four hundred and five patients with COPD were assessed for social frailty, dyspnea, and appetite. We also prospectively examined the number of acute exacerbation and unexpected hospitalization for 1 year. Results: Thirty-six percent of patients with COPD had social frailty. They had reduced appetite and more severe dyspnea [Simplified Nutritional Appetite Questionnaire score: odds ratio (OR) 0.81, 95% confidence interval (CI) 0.69‒0.95, p < 0.01; modified Medical Research Council score: OR 1.42, 95% CI 1.05‒1.93, P = 0.02] than patients without social frailty. Social frailty was not a risk factor for moderate acute exacerbation of COPD but a risk factor for severe acute exacerbation and all-cause unexpected hospitalization (severe acute exacerbation: ß, standardized regression coefficient: 0.13, 95% CI 0.01‒0.25, P = 0.04, unexpected hospitalization: ß 0.17, 95% CI 0.05‒0.29, P = 0.01). Conclusion: The prevalence of social frailty is 36%; however, social frailty has a marked clinical impact in patients with COPD.

Improvement of sleep parameters by titration polysomnography could predict adherence to positive airway pressure therapy in obstructive sleep apnea.

STUDY OBJECTIVES: Poor adherence to continuous positive airway pressure (CPAP) has been a critical issue in treating obstructive sleep apnea. Because long-term CPAP adherence may be established shortly after treatment begins, early intervention is essential. This study aimed to identify the potential factors affecting CPAP therapy adherence during diagnostic polysomnography and auto CPAP titration polysomnography. METHODS: This retrospective observational study included 463 patients with obstructive sleep apnea who underwent consecutive diagnostic polysomnography and titration polysomnography. We recorded their demographic, anthropometric, and lifestyle factors and obtained self-reported comments regarding their sleep status following both polysomnography evaluations. CPAP adherence was evaluated following 3 months of treatment. RESULTS: A total of 312 patients (67.4%) fulfilled the criteria for good adherence. Each patient's CPAP adherence was categorized as "poor" (< 4 hours/night or <70% of nights), "good" (≥ 4 hours/night and ≥ 70% of nights), or "excellent" (≥ 6 hours/night and ≥ 80% of nights). There were no significant differences in arterial oxyhemoglobin saturation measured by pulse oximetry and apnea-hypopnea index during diagnostic polysomnography among 3 groups. The polysomnographic evaluations indicated that patients with better adherence displayed more significant improvements in sleep parameters, including apnea-hypopnea index, sleep efficacy, sleep latency, and sleep architecture, which were correlated with an improvement in self-reported sleep quality. CONCLUSIONS: Polysomnographic evaluations enabled CPAP adherence prediction and a comparison of self-reported sleep quality with and without CPAP; CPAP adherence led to improvements in polysomnographic parameters. Our findings suggest that titration polysomnography and self-reported sleep improvement with CPAP could be used for adherence prediction in clinical practice. CITATION: Shirahata T, Uchida Y, Uchida T, et al. Improvement of sleep parameters by titration polysomnography could predict adherence to positive airway pressure therapy in obstructive sleep apnea. J Clin Sleep Med. 2023;19(8):1465-1473.

A case of Talaromyces marneffei infection that required differentiation from Pneumocystis pneumonia.

We report a case of Talaromyces marneffei fungemia in a patient with HIV infection with a history of travelling to southern China. At first, Pneumocystis pneumonia was considered in this case because chest CT images showed typical ground-glass opacity and elevated ß-D-glucan levels. However, PCR testing of sputum for Pneumocystis jirovecii was negative and a filamentous fungus was isolated from blood cultures. The cultured fungus was subsequently identified as T. marneffei, and the patient was considered to have pneumonia caused by this organism. However, skin disease and lymphadenopathy, which are common in T. marneffei infections, were not observed during the disease course. This patient was successfully treated with voriconazole and consequently the chest CT shadow disappeared. In the present case, T. marneffei infection required differentiation from pneumonia with Pneumocystis jirovecii infection.

Fetal Lung Cells Transfer Improves Emphysematous Change in a Mouse Model of Neutrophil Elastase-Induced Lung Emphysema.

Recently, several studies for lung regeneration have been reported. However, regenerating the lung tissue by the transfer of any cells directly to the lung has been hardly successful. The aim of this study was to evaluate the effect of fetal lung cells (FLCs) in a mouse model of lung emphysema. C57BL/6 mice were stimulated with neutrophil elastase (NE) intra-tracheally (i.t.) to generate lung emphysema. To collect fetal lung cells, C57BL/6-Tg (CAG-EGFP) mice were bred for 14 days. Before delivery, the bred mice were euthanized, and fetal lungs were harvested from the fetal mice and the cells were collected. The FLCs were transferred i.t. 24 h after the NE instillation. Four weeks after the NE instillation, mice were euthanized, and the samples were collected. The mean linear intercept (MLI) was significantly prolonged in the NE instillation group compared to the control group. However, in the FLCs transfer group stimulated with NE, the MLI became shorter than the NE-stimulated group without an FLCs transfer. This result shows that an FLCs transfer inhibited the progression of lung emphysema. Additionally, motility of the mice was also improved by the FLCs transfer. These results indicate that transfer of the FLCs, which were presumed to be progenitor cells for lung tissue, may improve the emphysematous change.

Treatment Resistance in Severe Asthma Patients With a Combination of High Fraction of Exhaled Nitric Oxide and Low Blood Eosinophil Counts.

Background: Combining a fraction of exhaled nitric oxide (FeNO) and blood eosinophil count (B-EOS) may be a useful strategy for administration of biologics such as anti-IgE or anti-IL-5 to patients with type 2 inflammatory-predominant severe asthma and is important to be elucidated considering the increasing use of biologics. Methods: This cross-sectional study analyzed the clinical data from 114 adult patients with severe asthma, who were treated at Saitama Medical University Hospital. The eligible patients were stratified into four subgroups defined by thresholds of FeNO and blood eosinophil (B-EOS) counts to detect sputum eosinophilia, using the receiver operating characteristic curve analysis. A total of 75 patients with optimal samples were stratified into four subtypes defined by thresholds of sputum eosinophilia and neutrophilia. Clinical characteristics, pattern of biologics, and distribution of sputum subtypes were analyzed in the stratified subclasses according to the FeNO and B-EOS thresholds. The asthma exacerbation (AE)-free time of the FeNO/B-EOS subgroups and any biologics treatment including anti-IgE or anti-IL-5 use were examined using the Kaplan-Meier method. The hazard ratios (HRs) for AE-free time were examined using the Cox proportional hazard model. Results: The optimal cutoff values for prediction of sputum eosinophilia were defined as ≥2.7% wherein for FeNO as ≥27 ppb and B-EOS as ≥265/µL were considered. The high-FeNO subgroups showed significant high total IgE, compared with the low FeNO. The high-FeNO/high-B-EOS and the high-FeNO/low-B-EOS subgroups showed the largest prevalence of mepolizumab and benralizumab use among the other FeNO/B-EOS, respectively. The high-FeNO/low-B-EOS showed the largest frequency of AEs, high HR, and the shortest AE-free time, among the other FeNO/B-EOS. The sputum eosinophil-predominant subtype was the great majority in the high FeNO/high B-EOS. A diverse distribution of sputum leukocyte-predominant subtype was observed in the other FeNO/B-EOS. The subsequent AE-free time and its HR were comparable among the biologics use groups. Conclusion: The strategy of classifying severe asthma based on the combination of FeNO and B-EOS proposes particular refractory type 2 severe asthma and underlying airway inflammation as a feasible trait for optimal biologics use.

Responses of CO2 emissions and soil microbial community structures to organic amendment in two contrasting soils in Zambia.

In sub-Saharan Africa, efforts have been made to increase soil carbon (C) content in agricultural ecosystems due to severe soil degradation. The use of organic materials is a feasible method for recovering soil organic C; however, the effects of organic amendments on soil microbial communities and C cycles under C-limited soil conditions are still unknown. In this study, we conducted field experiments in Zambia using organic amendments at two sites with contrasting C content. At both sites, temporal changes in soil carbon dioxide (CO2) emissions and prokaryotic community structures were monitored during the crop growing season (126 days). The organic amendments increased CO2 emissions and prokaryotic abundance at the Kabwe site, whereas no direct impacts were observed at the Lusaka site. We also observed a larger temporal variability in the soil microbial community structure at Kabwe than that at Lusaka. These contrasting results between the two soils may be due to the microbial community stability differences between each site. However, as organic amendments have considerable potential to enhance microbial abundance and consequently sequester C at the Kabwe site, site-specific strategies are required to address the issues of soil C depletion in drylands.

Serum IL-28A/IFN-λ2 is linked to disease severity of COVID-19.

Type III interferons (IFNs) play an important role in respiratory viral infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study aimed to determine whether the expression of serum type III IFNs predicted disease severity among patients with the coronavirus disease (COVID-19). A retrospective cohort study was conducted of patients admitted to a single hospital between March 21, 2020, and March 31, 2021. Patients were divided into mild to moderate I (MM) and moderate II to severe (MS) groups based on the COVID-19 severity classification developed by the Japanese Ministry of Health, Labor and Welfare. A total of 257 patients were included in the analysis. Human interleukin-28A (IL-28A/IFN-λ2) expression was significantly lower, and interleukin (IL)-6 expression was significantly higher in the MS group than in the MM group (both p < 0.001). In addition, IL-28A/IFN-λ2 was statistically significantly inversely correlated with the time from disease onset to negative SARS-CoV-2 PCR results (p = 0.049). Multivariable logistic regression analysis showed that IL-28A/IFN-λ2 was an independent predictor of disease severity (p = 0.021). The low expression of IL-28A/IFN-λ2 may serve as a serum biomarker that predicts the severity of COVID-19, possibly through the mechanism of delayed viral elimination.

Comprehensive Gene Expression Signature Using RNA-Seq in Airways of Mouse Model of Severe Asthma with Fungal Sensitization.

INTRODUCTION: Inhalation of fungal allergens induces airway epithelial damage following airway inflammation and excessive mucus secretion, which can lead to severe asthma with fungal sensitization (SAFS). Comprehensive gene expression analysis in Alternaria-exposed mouse airways, a model of SAFS, has not been conducted. METHODS: BALB/c mice received intranasal administration of Alternaria extract or phosphate-buffered saline twice a week for 6 weeks. Lung sections and bronchoalveolar lavage fluid were obtained to assess airway inflammation. RNA-Seq in the central airway was performed, and gene ontology (GO) analysis and gene set enrichment analysis (GSEA) were conducted for pathway analyses. An in vitro experiment using human airway epithelial cell 16HBE14o- was performed to validate the RNA-Seq findings. RESULTS: Eosinophilic airway inflammation with mucus overproduction and airway remodeling was observed in mice exposed to Alternaria. RNA-Seq analysis revealed 403 upregulated and 108 downregulated genes in airways of Alternaria-exposed mice. In GO analysis, the functions of immunoglobulin (Ig) receptor binding, Ig production, inflammatory response, and T-cell activation were upregulated, while those of keratinization and defense response to other organisms were downregulated. GSEA revealed positive enrichment in T-cell receptor complex, immunological synapse, antigen binding, mast cell activation, and Ig receptor binding, and negative enrichment in keratinization and cornification in Alternaria-exposed mice relative to control. Alternaria exposure to 16HBE14o- cells validated the downregulation of epithelial keratinization-related genes, including SPRR1A, SPRR1B, and KRT6B. CONCLUSION: RNA-Seq analysis showed that Alternaria exposure induced inflammatory response and impaired defense mechanisms in mice airway epithelium, which might be therapeutic targets for SAFS.

Predicting the presence and severity of obstructive sleep apnea based on mandibular measurements using quantitative analysis of facial profiles via three-dimensional photogrammetry.

BACKGROUND: In obstructive sleep apnea (OSA), the upper airway is obstructed during sleep due to obesity and/or posterior collapse of the tongue root. Maxillofacial morphological abnormalities increase the risk of OSA in the Asian population. This study sought to elucidate whether three-dimensional (3D) photogrammetry measurements correlate with the severity of OSA irrespective of sex and degree of obesity. METHODS: A prospective pilot study was performed, in which 37 consecutive adult patients (M/F = 28/9) underwent polysomnography and 3D photogrammetry in the supine position for the diagnosis of OSA. Measurements obtained from 3D photogrammetry included mandibular width (Mw), mandibular length (Ml), mandibular depth (Md), mandibular width-length angle (Mwla), and mandibular area (Ma). The effects of sex and body mass index (BMI) on the measurements and their association with the apnea-hypopnea index (AHI) were statistically analyzed. The inter-rater reliability of the measurements was evaluated using intraclass correlation coefficients (ICC). RESULTS: Mwla (R = 0.73, p < 0.01), Mw (R = 0.39, p < 0.05), and Md (R = -0.34, p < 0.05) were significantly correlated with the severity of OSA. On multivariate analysis, Mwla (p < 0.01) and Md (p < 0.05) remained independent factors for AHI after adjusting for sex, age, BMI, and neck circumference. In addition, diagnosability analysis revealed that Mwla was useful for identifying the presence of OSA (AHI ≥5) (cutoff: 78.6°, sensitivity: 0.938, specificity: 0.800, area under the curve: 0.931). The ICC was >0.9, showing high reliability. CONCLUSIONS: This study suggests that Mwla measured using 3D photogrammetry can predict the presence of OSA and correlates with the severity of OSA, independent of obesity and sex.

Characteristics of and reasons for patients with chronic obstructive pulmonary disease to continue smoking, quit smoking, and switch to heated tobacco products.

INTRODUCTION: Smoking is the leading cause of chronic obstructive pulmonary disease (COPD), and smoking cessation is the most effective treatment for patients with COPD. However, few studies have investigated the continuation/cessation of smoking and heated tobacco products (HTP) in patients with COPD. The objective of this study was to examine the characteristics of patients with COPD, those who are current smokers and those who switched from cigarettes to HTP, and to examine the reason for the continuation or cessation of smoking. METHODS: This multicenter, cross-sectional study included 411 outpatients with COPD. Data for this study were part of a study conducted for a comprehensive evaluation of the smoking status and clinical factors in patients with COPD and their families. RESULTS: Logistic regression analysis revealed that a younger age, longer duration of smoking, fewer daily cigarettes, and lower modified Medical Research Council (mMRC) dyspnea score, and a lower Simplified Nutritional Appetite Questionnaire (SNAQ) score for appetite, were characteristics of current smokers (age OR=0.94; duration of smoking OR=1.07; number of cigarettes per day OR=0.94; mMRC OR=0.68; SNAQ OR=0.83; p<0.05). The logistic regression analysis model showed that a younger age and higher education level were associated with the use of HTP (age OR=0.83; higher education level OR=4.63; p<0.05). Many of the current smokers displayed smoking behaviors that are not guaranteed to be safe, such as reducing smoking or switching to lighter cigarettes or HTP. CONCLUSIONS: Patients with COPD who continue smoking tended to have low appetite as well as smoking behaviors that are not guaranteed to be safe. Physicians should provide appropriate guidance to these patients on smoking cessation.

Clinical evaluation of rush immunotherapy using house dust mite allergen in Japanese asthmatics.

BACKGROUND: Allergen immunotherapy (AIT) is a specific treatment of administering clinically important allergens to patients who have allergic diseases. In Japan, the standardized house dust mite (HDM) allergen for subcutaneous immunotherapy (SCIT) was approved in 2015, and we then introduced rush-immunotherapy (rush-IT) using the standardized HDM allergen for HDM-sensitive asthmatics. However, little data are available on the safety and effectiveness of rush-HDM-IT, especially for Japanese asthmatics. OBJECTIVE: The objective of this study was to examine the safety and clinical effectiveness of rush-IT using the standardized HDM for HDM-sensitive Japanese asthmatics. METHODS: Thirteen HDM-sensitive asthmatics who received rush-HDM-IT and 12 HDM-sensitive asthmatic controls were enrolled. To evaluate the safety, the number of systemic reaction (SR) events, including anaphylaxis, was assessed. To evaluate the effectiveness, changes in the treatment step, dose of inhaled corticosteroid, and asthma control after rush-HDM-IT and the subsequent maintenance SCIT were assessed. Changes in the HDM-induced production of type 2 cytokines from peripheral blood mononuclear cells were also evaluated. RESULTS: Among the 12 patients who received rush-IT, 4 (30.7%) experienced a SR and 3 (23.1%) experienced anaphylaxis. However, the anaphylaxis was not severe (grade 3) in all cases, and they recovered in a short time. The treatment step of asthma was better and the dose of inhaled corticosteroid was lower in the rush-HDM-IT group than in the control group. The HDM-induced production of both interleukin (IL)-5 and IL-13 from peripheral blood mononuclear cells was significantly lower in the rush-HDM-IT group than in the control group. CONCLUSION: Rush-HDM-IT can be performed relatively safely in Japanese asthmatics. Furthermore, rush-HDM-IT and the subsequent maintenance SCIT provided clinical improvement in asthma patients, and was accompanied by the suppression of HDM-specific Th2-mediated systemic immune responses.

Liming improves the stability of soil microbial community structures against the application of digestate made from dairy wastes.

Lime is used to reduce soil acidification in agricultural soils. However, its effects on the soil microbial community are not well understood. Additionally, the soil microbial community is known to be influenced by fertilizers. However, the question remains whether liming influences the magnitude of fertilizers' impact on soil microbial communities. Therefore, an incubation experiment was performed to understand the effect of lime application (pH = 6.5 and 5.5 for the soils with and without lime, respectively) and fertilizer (digestate, urea and control) on the soil microbial community structures, stability and gene functions. Soils were sampled weekly after the application of fertilizers for a month. For microbial community analysis, DNA was extracted and sequenced targeting 16 S rRNA region. For gene abundances i.e 16 S rRNA, ammonia oxidizing archaea (AOA), ammonia oxidizing bacteria (AOB), nitrous oxide reductase (nosZ) and nitrite reductase (nirS) quantitative PCR was conducted. In results, the relative abundance of Actinobacteria was influenced more strongly by digestate in lime soils, while Alphaproteobacteria was influenced more strongly by digestate in the no lime soil. In NL treatments, digestate had a significant effect on more operational taxonomic units (146) compared to lime (127), indicating that lime application increased soil microbial community's stability. Liming and fertilizer had a significant effect on 16 S rRNA gene copy numbers with the highest values observed in lime plus digestate treatments. Soil pH had a significant effect on AOA, nosZ and nirS gene copy numbers with the highest values observed in lime treatments. In the lime treatments digestate application had a positive impact on AOB gene copy numbers but this was not the case for soils without liming treatments. These results indicate that soil pH and fertilizer type should be taken into consideration for the management of functional gene abundance in agricultural soils.

Yellow Nail Syndrome in Which Intranodal Lymphangiography Contributed to the Diagnosis.

Yellow nail syndrome (YNS) is a rare disease comprising the clinical triad of yellow nail discoloration, pleural effusion, and lower limb lymphedema. We encountered a difficult-to-treat case of YNS in which the diagnosis was finally made based on intranodal lymphangiography. An 84-year-old man was admitted to our hospital with pleural effusion and yellow-green discoloration of the nails, accompanied by onychomycosis and limb lymphedema. Intranodal lymphangiography revealed a slow contrast flow and narrowing of the thoracic duct, suggesting lymphatic duct dysplasia and leading to the diagnosis of YNS.

Soil Bacterial Diversity Is Positively Correlated with Decomposition Rates during Early Phases of Maize Litter Decomposition.

This study aimed to investigate the effects of different levels of soil- and plant-associated bacterial diversity on the rates of litter decomposition, and bacterial community dynamics during its early phases. We performed an incubation experiment where soil bacterial diversity (but not abundance) was manipulated by autoclaving and reinoculation. Natural or autoclaved maize leaves were applied to the soils and incubated for 6 weeks. Bacterial diversity was assessed before and during litter decomposition using 16S rRNA gene metabarcoding. We found a positive correlation between litter decomposition rates and soil bacterial diversity. The soil with the highest bacterial diversity was dominated by oligotrophic bacteria including Acidobacteria, Nitrospiraceae, and Gaiellaceae, and its community composition did not change during the incubation. In the less diverse soils, those taxa were absent but were replaced by copiotrophic bacteria, such as Caulobacteraceae and Beijerinckiaceae, until the end of the incubation period. SourceTracker analysis revealed that litter-associated bacteria, such as Beijerinckiaceae, only became part of the bacterial communities in the less diverse soils. This suggests a pivotal role of oligotrophic bacteria during the early phases of litter decomposition and the predominance of copiotrophic bacteria at low diversity.

[BRONCHIAL ASTHMA WITH VOCAL CORD DYSFUNCTION DIFFERENTIATED FROM SEVERE ASTHMA BY BRONCHOSCOPY].

Although an important cause of vocal cord dysfunction (VCD) is psychogenic reaction, VCD may be associated with severe asthma and must be distinguished from the disease. A 30-years-old woman was admitted to our hospital with dyspnea despite treatment for asthma. Inspiratory stridor and expiratory wheezes were noted, and neck and chest computed tomography showed normal airways and lungs. Fractional exhaled nitric oxide levels were also normal. Pulmonary function test with a flow-volume loop curve showed normal expiratory loop with flattening of the inspiratory loop after methacholine inhalation. During the attack, bronchoscopy revealed the vocal cord closing with stridor during the inspiratory phase. Therefore, the patient was diagnosed with VCD. The dyspnea improved with respiratory rehabilitation and pursed-lip breathing. VCD should be considered in the differential diagnosis of intractable severe asthma. In this case, bronchoscopy and bronchial inhalation challenge with methacholine helped in the diagnosis.