Bimolecular Peroxy Radical (RO2) Reactions and Their Relevance in Radical Initiated Oxidation of Hydrocarbons.

The kinetics of peroxy radical (RO2) reactions have been of long-standing interest in atmospheric and combustion chemistry. Nevertheless, the lack of kinetic studies at higher temperatures for their reactions with other radicals such as OH has precluded the inclusion of this class of reactions in detailed kinetics models developed for combustion applications. In this work, guided by the limited room-temperature experimental studies on selected alkyl-peroxy radicals and literature theoretical kinetics on the prototypical CH3O2 + OH system, we have performed parametric studies on the effect of uncertainties in the rate coefficients and branching ratios to potential product channels for RO2 + OH reactions at higher temperatures. Literature kinetics models were used to simulate autoignition delays, laminar flame speeds, and speciation profiles in flow and stirred reactors for a variety of common combustion-relevant fuels. Inclusion of RO2 + OH reactions was found to retard autoignition in fuel-lean (φ = 0.5) mixtures of ethane and dimethyl ether in air. The observed effects were noticeably more pronounced in ozone-enriched combustion of ethane and dimethyl ether. The simulations also examined the influence of ozone doping levels, pressures, and equivalence ratios for both ethane and dimethyl ether oxidation. Sensitivity and flux analyses revealed that the RO2 + OH reaction is a significant sink of RO2 radicals at the early stage of autoignition, affecting fuel oxidation through RO2 ↔ QOOH, RO2 ↔ alkene + HO2, or RO2 + HO2 ↔ ROOH + O2. Additionally, the kinetic stability of the trioxide formed from RO2 + OH reactions was investigated using master equation analyses. Last, we discuss other bimolecular reactions that are missing in literature kinetics models but are relevant to hydrocarbon oxidation initiated by external radical sources (plasma-enhanced, ozone-enriched combustion, etc.). The present simulations provide a strong motivation for better characterizing the bimolecular kinetics of peroxy radicals.

Modeling-Experiment-Theory Analysis of Reactions Initiated from Cl + Methyl Formate.

Methyl formate (MF; CH3OCHO) is the smallest representative of esters, which are common components of biodiesel. The present study characterizes the thermal dissociation kinetics of the radicals formed by H atom abstraction from MF─CH3OCO and CH2OCHO─through a combination of modeling, experiment, and theory. For the experimental effort, excimer laser photolysis of Cl2 was used as a source of Cl atoms to initiate reactions with MF in the gas phase. Time-resolved species profiles of MF, Cl2, HCl, CO2, CH3, CH3Cl, CH2O, and CH2ClOCHO were measured and quantified using photoionization mass spectrometry at temperatures of 400-750 K and 10 Torr. The experimental data were simulated using a kinetic model, which was informed by ab initio-based theoretical kinetics calculations and included chlorine chemistry and secondary reactions of radical decomposition products. We calculated the rate coefficients for the H-abstraction reactions Cl + MF → HCl + CH3OCO (R1a) and Cl + MF → HCl + CH2OCHO (R1b): k1a,theory = 6.71 × 10-15·T1.14·exp(-606/T) cm3/molecule·s; k1b,theory = 4.67 × 10-18·T2.21·exp(-245/T) cm3/molecule·s over T = 200-2000 K. Electronic structure calculations indicate that the barriers to CH3OCO and CH2OCHO dissociation are 13.7 and 31.6 kcal/mol and lead to CH3 + CO2 (R3) and CH2O + HCO (R5), respectively. The master equation-based theoretical rate coefficients are k3,theory (P = ∞) = 2.94 × 109·T1.21·exp(-6209/T) s-1 and k5,theory (P = ∞) = 8.45 × 108·T1.39·exp(-15132/T) s-1 over T = 300-1500 K. The calculated branching fractions into R1a and R1b and the rate coefficient for R5 were validated by modeling of the experimental species time profiles and found to be in excellent agreement with theory. Additionally, we found that the bimolecular reactions CH2OCHO + Cl, CH2OCHO + Cl2, and CH3 + Cl2 were critical to accurately model the experimental data and constrain the kinetics of MF-radicals. Inclusion of the kinetic parameters determined in this study showed a significant impact on combustion simulations of larger methyl esters, which are considered as biodiesel surrogates.

Trends and an Online Survey on the Use of Rigid Bronchoscopy in Korea.

BACKGROUND: Although almost all interventional pulmonologists agree that rigid bronchoscopy is irreplaceable in the field of interventional pulmonology, less is known about the types of diseases that the procedure is used for and what difficulties the operators face during the procedure. The purpose of this study is to evaluate what diseases rigid bronchoscopy is used for, whether it is widely used, and what challenges the operators face in Korea. METHODS: We enrolled 14 hospitals in this retrospective cohort of patients who underwent rigid bronchoscopy between 2003 and 2020. An online survey was conducted with 14 operators to investigate the difficulties associated with the procedure. RESULTS: While the number of new patients at Samsung Medical Center (SMC) increased from 189 in 2003-2005 to 468 in 2018-2020, that of other institutions increased from 0 to 238. The proportion of SMC patients in the total started at 100% and steadily decreased to 59.2%. The proportion of malignancy as the indication for the procedure steadily increased from 29.1% to 43.0%, whereas post-tuberculous stenosis (25.4% to 12.9%) and post-intubation stenosis (19.0% to 10.9%) steadily decreased (all P for trends < 0.001). In the online survey, half of the respondents stated that over the past year they performed less than one procedure per month. The fewer the procedures performed within the last year, the more likely collaboration with other departments was viewed as a recent obstacle (Spearman correlation coefficient, rs = -0.740, P = 0.003) and recent administrative difficulties were encountered (rs = -0.616, P = 0.019). CONCLUSION: This study demonstrated that the number of patients undergoing rigid bronchoscopy has been increasing, especially among cancer patients. For this procedure to be used more widely, it will be important for beginners to systematically learn about the procedure itself as well as to achieve multidisciplinary consultation.

Effect of chlorhexidine Mouthrinse on prevention of microbial contamination during EBUS-TBNA: a randomized controlled trial.

BACKGROUND: Although endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive procedure, fatal infectious complications have been reported. However, adequate preventive strategies have not been determined. We aimed to investigate the effect of chlorhexidine mouthrinse on the prevention of microbial contamination during EBUS-TBNA. METHODS: In this single-center, assessor-blinded, parallel-group randomized controlled trial, we randomly assigned adult participants undergoing EBUS-TBNA using a convex probe to gargle for 1 minute with 100 mL of 0.12% chlorhexidine gluconate before EBUS-TBNA or to receive usual care (no chlorhexidine mouthrinse). Aspiration needle wash samples were collected immediately after completion of EBUS-TBNA by instilling sterile saline into the used needle. The primary outcome was colony forming unit (CFU) counts per mL of needle wash samples in aerobic cultures. Secondary outcomes were CFU counts per mL of needle wash samples in anaerobic cultures, fever within 24 hours after EBUS-TBNA, and infectious complications within 4 weeks after EBUS-TBNA. RESULTS: From January 2021 to June 2021, 106 patients received either chlorhexidine mouthrinse (n = 51) or usual care (n = 55). The median CFU counts of needle wash samples in aerobic cultures were not significantly different in the two groups (10 CFU/mL vs 20 CFU/mL; P = 0.70). There were no significant differences between the groups regarding secondary outcomes, including median CFU counts in anaerobic cultures (P = 0.41) and fever within 24 hours after EBUS-TBNA (11.8% vs 5.6%, P = 0.31). There were no infectious complications within 4 weeks in both groups. CONCLUSIONS: Chlorhexidine mouthrinse did not reduce CFU counts in needle wash samples of EBUS-TBNA. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04718922 . Registered on 22/01/2021.

Unconjugated PLGA nanoparticles attenuate temperature-dependent ß-amyloid aggregation and protect neurons against toxicity: implications for Alzheimer's disease pathology.

Conversion of ß-amyloid (Aß) peptides from soluble random-coil to aggregated protein enriched with ß-sheet-rich intermediates has been suggested to play a role in the degeneration of neurons and development of Alzheimer's disease (AD) pathology. Aggregation of Aß peptide can be prompted by a variety of environmental factors including temperature which can influence disease pathogenesis. Recently, we reported that FDA-approved unconjugated poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles can have beneficial effects in cellular and animal models of AD by targeting different facets of the Aß axis. In this study, using biochemical, structural and spectroscopic analyses, we evaluated the effects of native PLGA on temperature-dependent Aß aggregation and its ability to protect cultured neurons from degeneration. Our results show that the rate of spontaneous Aß1-42 aggregation increases with a rise in temperature from 27 to 40 °C and PLGA with 50:50 resomer potently inhibits Aß aggregation at all temperatures, but the effect is more profound at 27 °C than at 40 °C. It appears that native PLGA, by interacting with the hydrophobic domain of Aß1-42, prevents a conformational shift towards ß-sheet structure, thus precluding the formation of Aß aggregates. Additionally, PLGA triggers disassembly of matured Aß1-42 fibers at a faster rate at 40 °C than at 27 °C. PLGA-treated Aß samples can significantly enhance viability of cortical cultured neurons compared to neurons treated with Aß alone by attenuating phosphorylation of tau protein. Injection of native PLGA is found to influence the breakdown/clearance of Aß peptide in the brain. Collectively, these results suggest that PLGA nanoparticles can inhibit Aß aggregation and trigger disassembly of Aß aggregates at temperatures outside the physiological range and can protect neurons against Aß-mediated toxicity thus validating its unique therapeutic potential in the treatment of AD pathology.

Genome-wide association study of non-tuberculous mycobacterial pulmonary disease.

BACKGROUND: The prevalence of non-tuberculous mycobacterial pulmonary disease (NTM-PD) is increasing in South Korea and many parts of the world. However, the genetic factors underlying susceptibility to this disease remain elusive. METHODS: To identify genetic variants in patients with NTM-PD, we performed a genome-wide association study with 403 Korean patients with NTM-PD and 306 healthy controls from the Healthy Twin Study, Korea cohort. Candidate variants from the discovery cohort were subsequently validated in an independent cohort. The Genotype-Tissue Expression (GTEx) database was used to identify expression quantitative trait loci (eQTL) and to conduct Mendelian randomisation (MR). RESULTS: We identified a putatively significant locus on chromosome 7p13, rs849177 (OR, 2.34; 95% CI, 1.71 to 3.21; p=1.36×10-7), as the candidate genetic variant associated with NTM-PD susceptibility. Its association was subsequently replicated and the combined p value was 4.92×10-8. The eQTL analysis showed that a risk allele at rs849177 was associated with lower expression levels of STK17A, a proapoptotic gene. In the MR analysis, a causal effect of STK17A on NTM-PD development was identified (ß, -4.627; 95% CI, -8.768 to -0.486; p=0.029). CONCLUSIONS: The 7p13 genetic variant might be associated with susceptibility to NTM-PD in the Korean population by altering the expression level of STK17A.

Impact of Sleep Duration on Mortality and Quality of Life in Chronic Kidney Disease: Results from the 2007-2015 KNHANES.

INTRODUCTION: In the general population, short and long sleep durations have been associated with adverse health outcomes. However, this association remains unclear in patients with chronic kidney disease (CKD). We examined the relationship of sleep duration to mortality and health-related quality of life (HRQOL) in individuals with CKD. METHODS: A total of 1,783 adults with CKD who participated in the 2007-2015 Korea National Health and Nutrition Examination Survey were analyzed. CKD was defined as an estimated glomerular filtration rate of <60 mL/min per 1.73 m2. Participants were categorized into 3 groups according to self-reported sleep duration: <6 h (short sleepers), 6-8 h, and >8 h (long sleepers). The outcome variables were all-cause mortality and HRQOL. HRQOL was assessed using the European Quality of Life-5 Dimensions (EQ-5D) index. RESULTS: During a median of 6.4 years, 481 (27%) deaths occurred. In unadjusted Cox regression analysis, long sleepers with CKD had an increased risk of death (hazard ratio [HR], 1.62; 95% confidence interval [CI]: 1.26-2.09). This significant association remained after adjusting for age, sex, and BMI (HR, 1.36; 95% CI: 1.05-1.75); however, it was lost after adjusting for CKD stage, social and lifestyle factors, and presence of comorbidities (HR, 1.15; 95% CI: 0.89-1.49). Compared with 6- to 8-h sleepers with CKD, long sleepers with CKD had significantly worse HRQOL in multivariable linear regression models. The adjusted means of the EQ-5D index were 0.80 (95% CI: 0.77-0.82) for short sleepers, 0.81 (95% CI: 0.80-0.82) for 6- to 8-h sleepers, and 0.76 (95% CI: 0.73-0.79) for long sleepers (p = 0.01). DISCUSSION/CONCLUSION: Long sleep duration is associated with poor HRQOL in Korean adults with CKD. The weak association between long sleep duration and mortality was attenuated after multivariable adjustment in this study.

Sleep Duration and Its Associations with Mortality and Quality of Life in Chronic Obstructive Pulmonary Disease: Results from the 2007-2015 KNAHNES.

BACKGROUND: While extreme sleep duration negatively affects mortality and health-related quality of life (HRQOL) in general populations, the relationship remains uncertain in patients with chronic obstructive pulmonary disease (COPD). OBJECTIVES: To evaluate the association between sleep duration and mortality and HRQOL in patients with COPD. METHODS: We analyzed 3,349 participants with COPD enrolled in the 2007-2015 Korea National Health and Nutrition Examination Survey (KNHANES). Participants aged 40 years or older with a smoking history and prebronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) <0.7 were eligible. The participants were categorized as short sleepers (<6 h), 6-8 h, and long sleepers (>8) according to self-reported sleep duration. The outcome variables were all-cause mortality and HRQOL. HRQOL was measured using the European Quality of Life-5 Dimensions (EQ-5D) index. RESULTS: During a median of 6.5 years, 386 (11.5%) participants died. In unadjusted Cox regression analysis, short sleepers with COPD had an increased risk of death (hazard ratio, 1.35; 95% confidence interval [CI]: 1.07-1.71). However, this association was not significant after adjusting for sociodemographic factors, BMI, FEV1, and comorbidities. In unadjusted and adjusted multiple linear regression, short sleepers had significantly worse HRQOL. The adjusted means of the EQ-5D index were 0.88 (95% CI: 0.87-0.89) for short sleepers, 0.90 (95% CI: 0.90-0.91) for 6- to 8-h sleepers, and 0.89 (95% CI: 0.87-0.91) for long sleepers (p = 0.01). CONCLUSIONS: In patients with COPD, sleep duration was not associated with all-cause mortality. However, short sleep duration was significantly associated with worse HRQOL.

Improved Oxygenation After Prone Positioning May Be a Predictor of Survival in Patients With Acute Respiratory Distress Syndrome.

OBJECTIVES: Prone position ventilation improves oxygenation and reduces the mortality of patients with severe acute respiratory distress syndrome. However, there is limited evidence about which patients would gain most survival benefit from prone positioning. Herein, we investigated whether the improvement in oxygenation after prone positioning is associated with survival and aimed to identify patients who will gain most survival benefit from prone positioning in patients with acute respiratory distress syndrome. DESIGN: A retrospective cohort study. SETTING: Medical ICU at a tertiary academic hospital between 2014 and 2020. PATIENTS: Adult patients receiving prone positioning for moderate-to-severe acute respiratory distress syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The main outcomes were ICU and 28-day mortality. A total of 116 patients receiving prone positioning were included, of whom 45 (38.8%) were ICU survivors. Although there was no difference in PaO2:FIO2 ratio before the first prone session between ICU survivors and nonsurvivors, ICU survivors had a higher PaO2:FIO2 ratio after prone positioning than nonsurvivors, with significant between-group difference (p < 0.001). The area under the receiver operating characteristic curve of the percentage change in the PaO2:FIO2 ratio between the baseline and 8-12 hours after the first prone positioning to predict ICU mortality was 0.87 (95% CI, 0.80-0.94), with an optimal cutoff value of 53.5% (sensitivity, 91.5%; specificity, 73.3%). Prone responders were defined as an increase in PaO2:FIO2 ratio of greater than or equal to 53.5%. In the multivariate Cox regression analysis, prone responders (hazard ratio, 0.11; 95% CI, 0.05-0.25), immunocompromised condition (hazard ratio, 2.15; 95% CI, 1.15-4.03), and Sequential Organ Failure Assessment score (hazard ratio, 1.16; 95% CI, 1.06-1.27) were significantly associated with 28-day mortality. CONCLUSIONS: The PaO2:FIO2 ratio after the first prone positioning differed significantly between ICU survivors and nonsurvivors. The improvement in oxygenation after the first prone positioning was a significant predictor of survival in patients with moderate-to-severe acute respiratory distress syndrome.

Sleep duration and health-related quality of life in Korean adults: 2007-2015 Korea National Health and Nutrition Examination Survey.

PURPOSE: To evaluate the association of sleep duration with health-related quality of life (HRQOL) and examine the influence of age, sex, and common comorbidities on this association. METHODS: Using appropriate survey design, we analyzed 50,181 adults who participated in the 2007-2015 Korea National Health and Nutrition Examination Survey. Participants were categorized into five groups according to self-reported sleep duration ≤ 5 (short sleeper), 6, 7, 8, and ≥ 9 h (long sleeper). HRQOL was measured with the European Quality of Life-5 Dimensions (EQ-5D) index and visual analogue scale (VAS). RESULTS: In multiple linear regression, short sleep duration was associated with lower EQ-5D index (ß = - 0.024; 95% confidence interval [CI], - 0.027 to - 0.021) and lower EQ-VAS (ß = - 3.0; 95% CI, - 3.7 to - 2.3), and long sleep duration was associated with lower EQ-5D index (ß = - 0.016; 95% CI, - 0.021 to - 0.011) and lower EQ-VAS (ß = - 2.2; 95% CI, - 3.1 to - 1.3) compared with 7-h sleepers. Old-age (≥ 65 years old) short and long sleepers had significantly lower EQ-5D index than those of < 65 years old. When separated according to sex, men with long sleep and women with short sleep showed the lowest EQ-5D index. Short and long sleepers with hypertension, diabetes, hypercholesterolemia, cardiovascular disease, or depression showed significantly lower EQ-5D index than those without comorbidities. CONCLUSIONS: Extreme sleep duration was associated with poor HRQOL. Short and long sleepers with old age and comorbidities had significantly lower HRQOL than those without such conditions.

Mortality risk and causes of death in patients with non-cystic fibrosis bronchiectasis.

BACKGROUND: All-cause mortality risk and causes of death in bronchiectasis patients have not been fully investigated. The aim of this study was to compare the mortality risk and causes of death between individuals with bronchiectasis and those without bronchiectasis. METHODS: Patients with or without bronchiectasis determined based on chest computed tomography (CT) at one centre between 2005 and 2016 were enrolled. Among the patients without bronchiectasis, a control group was selected after applying additional exclusion criteria. We compared the mortality risk and causes of death between the bronchiectasis and control groups without lung disease. Subgroup analyses were also performed according to identification of Pseudomonas or non-tuberculous mycobacteria, airflow limitation, and smoking status. RESULTS: Of the total 217,702 patients who underwent chest CT, 18,134 bronchiectasis patients and 90,313 non-bronchiectasis patients were included. The all-cause mortality rate in the bronchiectasis group was 1608.8 per 100,000 person-years (95% confidence interval (CI), 1531.5-1690.0), which was higher than that in the control group (133.5 per 100,000 person-years; 95% CI, 124.1-143.8; P < 0.001). The bronchiectasis group had higher all-cause (adjusted hazard ratio (aHR), 1.26; 95% CI, 1.09-1.47), respiratory (aHR, 3.49; 95% CI, 2.21-5.51), and lung cancer-related (aHR, 3.48; 95% CI, 2.33-5.22) mortality risks than the control group. In subgroup analysis, patients with airflow limitation and ever smokers showed higher all-cause mortality risk among bronchiectasis patients. Therefore, we observed significant interrelation between bronchiectasis and smoking, concerning the risks of all-cause mortality (P for multiplicative interaction, 0.030, RERI, 0.432; 95% CI, 0.097-0.769) and lung cancer-related mortality (RERI, 8.68; 95% CI, 1.631-15.736). CONCLUSION: Individuals with bronchiectasis had a higher risk of all-cause, respiratory, and lung cancer-related mortality compared to control group. The risk of all-cause mortality was more prominent in those with airflow limitation and in ever smokers.

Outcome of Regular Inhaled Treatment in GOLD A Chronic Obstructive Pulmonary Disease Patients.

BACKGROUND: The 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommends regular bronchodilator therapy in all group A patients with chronic obstructive pulmonary disease (COPD). OBJECTIVE: The aim of this study was to evaluate whether regular inhaled treatment in group A patients with COPD improves their health outcomes, including exacerbations and symptoms. METHODS: We recruited patients from 2 Korean prospective cohorts. Eligible COPD patients had a modified Medical Research Council (mMRC) dyspnea score of <2, a St. George's Respiratory Questionnaire for COPD (SGRQ-C) total score of <25, and had no more than 1 exacerbation and no hospitalizations during the previous year. Incidence rates of exacerbations and changes in symptom scores were analyzed. RESULTS: After propensity score matching, there were 107 patient pairs, with and without regular inhaled treatment, who were followed up for mean times of 2.6 and 3.1 years, respectively. The incidence rates of exacerbations in those with and without regular treatment were not significantly different (incidence rate ratio 1.24 [95% CI 0.68 to 2.25]). Significant differences in favor of regular treatment were observed at 6 and 12 months for the SGRQ-C total scores (mean between-group difference -4.7 [95% CI -7.9 to -1.6] and -4.8 [95% CI -7.9 to -1.7], respectively). Regular treatment with a long-acting bronchodilator was also associated with significantly better scores on the SGRQ-C (mean between-group difference -5.0 [95% CI -8.6 to -1.4]) compared to no regular treatment at 12 months of follow-up. CONCLUSIONS: Regular inhaled treatment in group A patients with COPD was associated with a symptomatic benefit but not with a reduction of exacerbation rates.

Role of ethambutol and rifampicin in the treatment of Mycobacterium avium complex pulmonary disease.

BACKGROUND: A three-drug regimen (macrolide, ethambutol, and rifampicin) is recommended for the treatment of Mycobacterium avium complex pulmonary disease (MAC-PD). Although macrolide has proven efficacy, the role of ethambutol and rifampicin in patients without acquired immune deficiency syndrome is not proven with clinical studies. We aimed to clarify the roles of ethambutol and rifampicin in the treatment of MAC-PD. METHODS: Patients treated for MAC-PD between March 1st, 2009 and October 31st, 2018 were reviewed retrospectively. Rates of culture conversion, microbiological cure, treatment failure, and recurrence were compared according to the maintenance (≥6 months) of ethambutol or rifampicin with macrolide. RESULTS: Among the 237 patients, 122 (51.5%) maintained ethambutol and rifampicin with macrolide, 58 (24.5%) maintained ethambutol and macrolide, 32 (13.5%) maintained rifampicin and macrolide, and 25 (10.6%) maintained macrolide only. Culture conversion was reached for 190/237 (80.2%) patients and microbiological cure was achieved for 129/177 (72.9%) who completed the treatment. Treatment failure despite ≥12 months of treatment was observed in 66/204 (32.4%), and recurrence was identified in 16/129 (12.4%) who achieved microbiological cure. Compared with maintenance of macrolide only, maintenance of ethambutol, rifampicin or both with macrolide were associated with higher odds of culture conversion [odds ratio (OR), 95% confidence interval (CI): 18.06, 3.67-88.92; 15.82, 2.38-105.33; and 17.12, 3.93-74.60, respectively]. Higher odds of microbiological cure were associated with maintenance of both ethambutol and rifampicin with macrolide (OR, 95% CI: 5.74, 1.54-21.42) and macrolide and ethambutol (OR, 95% CI: 5.12, 1.72-15.24) but not macrolide and rifampicin. Maintenance of both ethambutol and rifampicin with macrolide was associated with lower odds of treatment failure (OR, 95% CI: 0.09, 0.01-0.53) compared with macrolide only, while maintenance of one of these with macrolide was not. Maintenance of both ethambutol and rifampicin or one of these with macrolide did not decrease the probability of recurrence when compared with macrolide only. CONCLUSIONS: Maintenance (≥6 months) of ethambutol and rifampicin with macrolide was associated with the most favorable treatment outcomes among patients with MAC-PD. Given the association between ongoing ethambutol use and microbiological cure, clinicians should maintain ethambutol unless definite adverse events develop.

Risk of acute exacerbations in chronic obstructive pulmonary disease associated with biomass smoke compared with tobacco smoke.

BACKGROUND: Risk of exacerbations in chronic obstructive pulmonary disease (COPD) associated with biomass smoke has not been well addressed, although biomass smoke is similar in composition to tobacco smoke. METHODS: To investigate whether the risk of exacerbations in COPD associated with biomass smoke differs from that in COPD associated with tobacco smoke, we recruited patients with COPD from two Korean multicenter prospective cohorts. In a multiple linear regression model, the standardized regression coefficient (ß) of biomass smoke exposure ≥25 years was most similar to that (ß') of tobacco smoke exposure ≥10 pack-years (ß = - 0.13 and ß' = - 0.14). We grouped patients with COPD into four categories based on the above cut-offs: Less Tobacco-Less Biomass, Less Tobacco-More Biomass, More Tobacco-Less Biomass, and More Tobacco-More Biomass. The main outcome was the incidence of moderate or severe exacerbations. RESULTS: Among 1033 patients with COPD, 107 were included in Less Tobacco-Less Biomass (mean age: 67 years, men: 67%), 40 in Less Tobacco-More Biomass (mean age: 70 years, men: 35%), 631 in More Tobacco-Less Biomass (mean age: 68 years, men: 98%), and 255 in More Tobacco-More Biomass (mean age: 69 years, men: 97%). The incidence rates of exacerbations were not significantly different between Less Tobacco-More Biomass and More Tobacco-Less Biomass (adjusted incidence rate ratio, 1.03; 95% confidence interval, 0.56-1.89; P = 0.921). No interaction between sex and tobacco and biomass smoke was observed. When propensity score matching with available covariates including age and sex was applied, a similar result was observed. CONCLUSIONS: Patients with COPD associated with biomass smoke and those with COPD associated with tobacco smoke had a similar risk of exacerbations. This suggests that patients with COPD associated with biomass smoke should be treated actively.

Progression and Treatment Outcomes of Lung Disease Caused by Mycobacterium abscessus and Mycobacterium massiliense.

BACKGROUND: Mycobacterium abscessus and Mycobacterium massiliense are grouped as the Mycobacterium abscessus complex. The aim of this study was to elucidate the differences between M. abscessus and M. massiliense lung diseases in terms of progression rate, treatment outcome, and the predictors thereof. METHODS: Between 1 January 2006 and 30 June 2015, 56 patients and 54 patients were diagnosed with M. abscessus and M. massiliense lung diseases, respectively. The time to progression requiring treatment and treatment outcomes were compared between the 2 groups of patients, and predictors of progression and sustained culture conversion with treatment were analyzed. In addition, mediation analysis was performed to evaluate the effect of susceptibility to clarithromycin on treatment outcomes. RESULTS: During follow-up, 21 of 56 patients with M. abscessus lung diseases and 21 of 54 patients with M. massiliense lung diseases progressed, requiring treatment. No difference was detected in the time to progression between the 2 patient groups. Lower body mass index, bilateral lung involvement, and fibrocavitary-type disease were identified as predictors of disease progression. Among the patients who began treatment, infection with M. massiliense rather than M. abscessus and the use of azithromycin rather than clarithromycin were associated with sustained culture conversion. The difference in treatment outcomes was partly mediated by the organism's susceptibility to clarithromycin. CONCLUSIONS: Progression rates were similar but treatment outcomes differed significantly between patients with lung disease caused by M. abscessus and M. massiliense. This difference in treatment outcomes was partly explained by the susceptibility of these organisms to clarithromycin.

The Relationship between Pulse Wave Velocity and Coronary Artery Stenosis and Percutaneous Coronary Intervention: a retrospective observational study.

BACKGROUND: Arterial stiffness has been suggested as a valuable predictor of coronary artery stenosis (CAS). However, little data are available on aortic stiffness and CAS in patients who have previously undergone percutaneous coronary artery intervention (PCI). The aim of this study was to investigate the association of arterial stiffness to CAS in patients with a history of PCI and those without a history of PCI. METHODS: We retrospectively studied 1093 consecutive patients who had undergone coronary angiography (CAG). Arterial stiffness was determined by brachial-ankle pulse wave velocity (baPWV) measured prior to CAG. RESULTS: In patients without a history of PCI, baPWV significantly increased in patients with CAS compared to that in patients without CAS (p < 0.001). However, among patients with a history of PCI, there was no significant difference in baPWV. Multivariate logistic regression analysis demonstrated that baPWV was an independent risk predictor for CAS in patients without a history of PCI, but not in those with a history of PCI (OR 1.106, 95% CI 1.039-1.177, p = 0.002). In CAS patients without a history of PCI, increased baPWV was significantly associated with multiple cardiovascular risk factors, multivessel involvement, and anatomical severity. CONCLUSIONS: Prediction of CAS by baPWV is significantly attenuated in patients with a history of PCI.

High Field Solid-State NMR Spectroscopy Investigation of (15)N-Labeled Rosette Nanotubes: Hydrogen Bond Network and Channel-Bound Water.

(15)N-labeled rosette nanotubes were synthesized and investigated using high-field solid-state NMR spectroscopy, X-ray diffraction, atomic force microscopy, and electron microscopy. The results established the H-bond network involved in the self-assembly of the nanostructure as well as bound water molecules in the nanotube's channel.

Anti-inflammatory effects of sucrose-derived oligosaccharides produced by a constitutive mutant L. mesenteroides B-512FMCM dextransucrase in high fat diet-fed mice.

Oligosaccharide (OS) is used as a sugar replacement as well as an ingredient in functional foods because of its beneficial effects, mainly on reducing calorie content and promoting intestinal health. By contrast, the effects of OS on inflammation are less well investigated. The purpose of this study was to investigate the effects of sucrose-derived OS on glucose control and inflammation in high fat (HF) diet-fed mice. Male C57BL6 mice were randomly assigned to six treatment groups (n = 10-14 mice per group): 1) lean control (CON), 2) HF control, 3) HF-low sucrose (LS, 100 mg/kg/day), 4) HF-high sucrose (HS, 1000 mg/kg/day), 5) HF-low OS (LOS, 100 mg/kg/day), and 6) HF-high OS (HOS, 1000 mg/kg/day). PBS (vehicle), sucrose, and OS were administered by stomach gavage. Body weight, food intake, and markers of liver function (activities of aspartate aminotransferase and alanine aminotransferase) were not affected by the treatments. HOS treatment decreased levels of serum glucose, insulin, and homeostasis model assessment-insulin resistance compared with sucrose treatment. However, serum adiponectin levels of the HOS group were higher than those of the sucrose groups. Serum levels of the pro-inflammatory cytokines interleukin-6 (IL-6) and fetuin-A were lower in the HOS group than in the sucrose groups. Hepatic gene expression levels of pro-inflammatory cytokines and related factors (fetuin-A, NF-κB, TLR4, TNF-alpha, and IL-6) were decreased and the levels of insulin signaling-related molecules (sirtuin 1, insulin receptor, and Akt) were increased in HOS-treated mice as compared with sucrose-treated mice. These results demonstrate that OS treatment is effective in improving glucose control and inflammation in high fat diet-fed mice.