Active tuberculosis (TB) has a greater burden of TB bacilli than latent TB and acts as an infection source for contacts. Latent tuberculosis infection (LTBI) is the state in which humans are infected with Mycobacterium tuberculosis without any clinical symptoms, radiological abnormality, or microbiological evidence. TB is transmissible by respiratory droplet nucleus of $1-5{\mu}m$ in diameter, containing 1-10 TB bacilli. TB transmission is affected by the strength of the infectious source, infectiousness of TB bacilli, immunoresistance of the host, environmental stresses, and biosocial factors. Infection controls to reduce TB transmission consist of managerial activities, administrative control, engineering control, environmental control, and personal protective equipment provision. However, diagnosis and treatment for LTBI as a national TB control program is an important strategy on the precondition that active TB is not missed. Therefore, more concrete evidences for LTBI management based on clinical and public perspectives are needed.

Chronic obstructive pulmonary disease (COPD) encompasses several clinical syndromes, most notably emphysema and chronic bronchitis. Most of the current treatments fail to attenuate severity and progression of the disease, thereby requiring better mechanistic understandings of pathogenesis to develop disease-modifying therapeutics. A number of theories on COPD pathogenesis have been promulgated wherein an increase in protease burden from chronic inflammation, exaggerated production of reactive oxygen species and the resulting oxidant injury, or superfluous cell death responses caused by enhanced cellular injury/damage were proposed as the culprit. These hypotheses are not mutually exclusive and together likely represent the multifaceted biological processes involved in COPD pathogenesis. Recent studies demonstrate that mitochondria are involved in innate immune signaling that plays important roles in cigarette smoke-induced inflammasome activation, pulmonary inflammation and tissue remodeling responses. These responses are reviewed herein and synthesized into a view of COPD pathogenesis whereby mitochondria play a central role.

There is no well-stated practical guideline for mechanically ventilated patients with or without acute respiratory distress syndrome (ARDS). We generate strong (1) and weak (2) grade of recommendations based on high (A), moderate (B) and low (C) grade in the quality of evidence. In patients with ARDS, we recommend low tidal volume ventilation (1A) and prone position if it is not contraindicated (1B) to reduce their mortality. However, we did not support high-frequency oscillatory ventilation (1B) and inhaled nitric oxide (1A) as a standard treatment. We also suggest high positive end-expiratory pressure (2B), extracorporeal membrane oxygenation as a rescue therapy (2C), and neuromuscular blockage for 48 hours after starting mechanical ventilation (2B). The application of recruitment maneuver may reduce mortality (2B), however, the use of systemic steroids cannot reduce mortality (2B). In mechanically ventilated patients, we recommend light sedation (1B) and low tidal volume even without ARDS (1B) and suggest lung protective ventilation strategy during the operation to lower the incidence of lung complications including ARDS (2B). Early tracheostomy in mechanically ventilated patients can be performed only in limited patients (2A). In conclusion, of 12 recommendations, nine were in the management of ARDS, and three for mechanically ventilated patients.

Transmission of tuberculosis (TB) is a recognized risk to patients and healthcare workers in healthcare settings. The literature review suggests that implementation of combination control measures reduces the risk of TB transmission. Guidelines suggest a three-level hierarchy of controls including administrative, environmental, and respiratory protection. Among environmental controls, installation of ventilation systems is a priority because ventilation reduces the number of infectious particles in the air. Natural ventilation is cost-effective but depends on climatic conditions. Supplemented intervention such as air-cleaning methods including high efficiency particulate air filtration and ultraviolet germicidal irradiation should be considered in areas where adequate ventilation is difficult to achieve. Personal protective equipment including particulate respirators provides additional benefit when administrative and environmental controls cannot assure protection.

Bronchodilators are the cornerstone of symptomatic chronic obstructive pulmonary disease (COPD) treatment. They are routinely recommended for symptom reduction, with a preference of long-acting over short-acting drugs. Bronchodilators are classified into two classes based on distinct modes of action, i.e., long-acting antimuscarinics (LAMA, once-daily and twice-daily), and long-acting ${\beta}2$-agonists (LABA, once-daily and twice-daily). In contrast to asthma management, evidence supports the efficacy of both classes of long-acting bronchodilators as monotherapy in preventing COPD exacerbations, with greater efficacy of LAMA drugs versus LABAs. Several novel LAMA/LABA fixed dose combination inhalers are currently approved for COPD maintenance treatment. These agents show superior symptom control to monotherapies, and some of these combinations have also demonstrated superior efficacy in exacerbation prevention versus monotherapies, or combinations of inhaled corticosteroids plus LABA. This review summarizes the current data on clinical effectiveness of bronchodilators alone or in combination to prevent exacerbations of COPD.

Somatic mutations that lead to hyperactivation of epidermal growth factor receptor (EGFR) signaling are detected in approximately 50% of lung adenocarcinoma in people from the Far East population and tyrosine kinase inhibitors are now the standard first line treatment for advanced disease. They have led to a doubling of progression-free survival and an increase in overall survival by more than 2 years. However, emergence of resistant clones has become the primary cause for treatment failure, and has created a new challenge in the daily management of patients with EGFR mutations. Identification of mechanisms leading to inhibitor resistance has led to new therapeutic modalities, some of which have now been adapted for patients with unsuccessful tyrosine kinase inhibitor treatment. In this review, we describe mechanisms of tyrosine kinase inhibitor resistance and the available strategies to overcoming resistance.

Background: Idiopathic pulmonary fibrosis is a common interstitial lung disease; it is a chronic, progressive, and fatal lung disease of unknown etiology. Over the last two decades, knowledge about the underlying mechanisms of pulmonary fibrosis has improved markedly and facilitated the identification of potential targets for novel therapies. However, despite the large number of antifibrotic drugs being described in experimental pre-clinical studies, the translation of these findings into clinical practices has not been accomplished yet. NADH:quinone oxidoreductase 1 (NQO1) is a homodimeric enzyme that catalyzes the oxidation of NADH to $NAD^+$ by various quinones and thereby elevates the intracellular $NAD^+$ levels. In this study, we examined the effect of increase in cellular $NAD^+$ levels on bleomycin-induced lung fibrosis in mice. Methods: C57BL/6 mice were treated with intratracheal instillation of bleomycin. The mice were orally administered with ${\beta}$-lapachone from 3 days before exposure to bleomycin to 1-3 weeks after exposure to bleomycin. Bronchoalveolar lavage fluid (BALF) was collected for analyzing the infiltration of immune cells. In vitro, A549 cells were treated with transforming growth factor ${\beta}1$ (TGF-${\beta}1$) and ${\beta}$-lapachone to analyze the extracellular matrix (ECM) and epithelial-mesenchymal transition (EMT). Results: ${\beta}$-Lapachone strongly attenuated bleomycin-induced lung inflammation and fibrosis, characterized by histological staining, infiltrated immune cells in BALF, inflammatory cytokines, fibrotic score, and TGF-${\beta}1$, ${\alpha}$-smooth muscle actin accumulation. In addition, ${\beta}$-lapachone showed a protective role in TGF-${\beta}1$-induced ECM expression and EMT in A549 cells. Conclusion: Our results suggest that ${\beta}$-lapachone can protect against bleomycin-induced lung inflammation and fibrosis in mice and TGF-${\beta}1$-induced EMT in vitro, by elevating the $NAD^+$/NADH ratio through NQO1 activation.

Background: Cystic fibrosis (CF) is an autosomal recessive disorder with several clinical presentations. This study was undertaken in the Azeri Turkish population in Iran, to investigate gender differences in the age at onset and diagnosis, age of death, and duration of illness of CF. Methods: The data of 331 CF patients from 2001 to 2015 was surveyed. Parameters including age, sex, ${\Delta}F508$ mutation, age at onset, age at diagnosis, age of death and clinical presentations were evaluated for both sexes, using descriptive analysis. The association of gender with these variables was studied using logistic regression, chi-square test and Mann-Whitney U test by SPSS version 18. Odds ratio with a confidence interval of 95% and $p{\leq}0.05$ was considered statistically significant. Results: The study included 191 males (57.7%) and 140 females (42.3%), all showing statistically significant difference (p<0.001). Age duration differed between genders. Male and female patients were further under 9 and 4 years, respectively. The occurrence of ${\Delta}F508$ mutation was 0.51 times more in females than in males. Age, diagnosis and sex were closely associated: males were diagnosed at a significantly later age than females (p=0.05). While this compression performed based on clinical presentations, males with respiratory disease had a later median age at diagnosis than females at lifespan (p=0.001). The risk of infertility in males was approximately two times greater than in females (p=0.02). Conclusion: These findings indicate gender differences in CF patients. Future studies are needed to establish other differences and evaluate the causes for the gender variations.

Background: Factors associated with the prognosis of patients with small cell lung cancer (SCLC) is relatively unknown, than of those with non-small cell lung cancer. This study was undertaken to identify the prognostic factors of SCLC. Methods: The medical records of 333 patients diagnosed with SCLC at tertiary hospital from January 1, 2008, to December 31, 2012 were retrospectively reviewed. Patients were categorized by age (${\leq}65$ years vs. >65 years) and by extent of disease (limited disease [LD] vs extensive disease [ED]). Overall survival and progression free survival rates were determined. Factors associated with prognosis were calculated using Cox's proportional hazard regression model. Results: Most baseline characteristics were similar in the LD and ED groups. Eastern Cooperative Oncology Group (ECOG) performance status (PS), first chemotherapy regimen, and prophylactic cranial irradiation (PCI) differed significantly in patients with LD and ED. Mean ECOG PS was significantly lower (p<0.001), first-line chemotherapy with etoposide-cisplatin was more frequent than with etoposide-carboplatin (p<0.001), and PCI was performed more frequently (p=0.019) in LD-SCLC than in ED-SCLC. Prognosis in the LD group was better in younger (${\leq}65$ years) than in older (>65 years) patients, but prognosis in the ED group was unrelated to age. Conclusion: This study showed that overall survival (OS) was significantly improved in younger than in older patients with LD-SCLC. Univariate and multivariate analyses showed that age, PCI and the sum of cycles were significant predictors of OS in patients with LD-SCLC. However, prognosis in the ED group was unrelated to age.

Background: Tuberculosis (TB) is a major health problem, and accurate and rapid diagnosis of multidrug-resistant (MDR) and extended drug-resistant (XDR) TB is important for appropriate treatment. In this study, performances of solid and liquid culture methods were compared with respect to MDR- and XDR-TB isolate recovery and drug susceptibility testing. Methods: Sputum specimens from 304 patients were stained with Ziehl-Neelsen method. Mycobacterium tuberculosis (Mtb) isolates were tested for recovery on $L{\ddot{o}wenstein$-Jensen (LJ) medium and the BacT Alert 3D system. For drug susceptibility testing of Mtb, isolates were evaluated on M-KIT plates and the BacT Alert 3D system. Results: The recovery rates were 94.9% (206/217) and 98.2% (213/217) for LJ medium and the BacT Alert 3D system, respectively (kappa coefficient, 0.884). The rate of drug resistance was 13.4% for at least one or more drugs, 6.0% for MDR-TB and 2.3% for XDR-TB. M-KIT plate and BacT 3D Alert 3D system were comparable in drug susceptibility testing for isoniazid (97.7%; kappa coefficient, 0.905) and rifampin (98.6%; kappa coefficient, 0.907). Antibiotic resistance was observed using M-KIT plates for 24 of the total 29 Mtb isolates (82.8%). Conclusion: The liquid culture system showed greater reduction in the culture period, as compared with LJ medium; however, drug susceptibility testing using M-KIT plates was advantageous for simultaneous testing against multiple drug targets.

Background: The aim of our study was to evaluate the prognostic value of Charlson's weighted index of comorbidities (WIC) in patients with prolonged acute mechanical ventilation (PAMV, ventilator care ${\geq}96$ hours). Methods: We retrospectively enrolled 299 Korean PAMV patients who were admitted in a medical intensive care unit (ICU) of a university-affiliated tertiary care hospital between 2008 and 2013. Survivors were defined as patients who survived for 60 days after ICU admission. Results: The patients' mean age was $65.1{\pm}14.1$ years and 70.6% were male. The mean ICU and hospital length of stay was $21.9{\pm}19.7$ and $39.4{\pm}39.1$ days, respectively. In addition, the 60-day mortality rate after ICU admission was 35.5%. The mean WIC was $2.3{\pm}1.8$, with significant differences between nonsurvivors and survivors ($2.7{\pm}2.1$ vs. $2.1{\pm}1.7$, p<0.05). The area under the curve of receiver-operating-characteristics curve for WIC was 0.593 (95% confidence interval [CI], 0.523-0.661; p<0.05). Based on Kaplan-Meier curves of 60-day survival, WIC ${\geq}5$ had statistically lower survival than WIC <5 (logrank test, p<0.05). In a multivariate Cox proportional hazard model, WIC ${\geq}5$ was associated with poor prognosis (hazard ratio, 1.901; 95% CI, 1.140-3.171; p<0.05). The mortality rate of patients with WIC ${\geq}5$ was 54.2%. Conclusion: Our study showed a WIC score ${\geq}5$ might be helpful in predicting 60-day mortality in PAMV patients.

Background: Specific immunoglobulin E (IgE) sensitization to staphylococcal enterotoxin (SE) has been recently considered to be related to allergic disease, including asthma. Despite studies on specific IgE (sIgE) to SE and its relationship to asthma diagnosis and severity, the association of sIgE to SE with airway hyperresponsiveness (AHR) remains unclear. Methods: We enrolled 81 asthma patients admitted to the Severance Hospital in Korea from March 1, 2013, to February 28, 2015 and retrospectively reviewed the electronic medical records of the enrolled subjects. The serum levels of sIgE to SE (A/B) of all subjects was measured using the ImmunoCAP 250 (Phadia) system with SE-sIgE positive defined as >0.10 kU/mL. Results: The SE-sIgE level was not significantly correlated with asthma severity (forced expiratory volume in 1 second [$FEV_1$], $FEV_1$/forced vital capacity, sputum eosinophils, and serum eosinophils), whereas the SE-sIgE level in patients with positive AHR ($mean{\pm}standard$ error of the mean, $0.606{\pm}0.273kU/mL$) was significantly higher than that in patients with negative AHR ($0.062{\pm}0.015kU/mL$, p=0.034). In regression analysis, SE sensitization (sIgE to SE ${\geq}0.010kU/mL$) was a significant risk factor for AHR, after adjustment for age, sex, $FEV_1$, and sputum eosinophils (odds ratio, 7.090; 95% confidence interval, 1.180-42.600; p=0.032). Prevalence of SE sensitization was higher in patients with allergic rhinitis and non-atopic asthma patients, as compared to patients without allergic rhinitis and atopic asthma patients, respectively, but without statistical significance. Conclusion: SE sensitization is significantly associated with AHR.

Systemic vasculitis involving the lung is a rare manifestation of myelodysplastic syndrome (MDS), and secondary vasculitis is considered to have poor prognosis. A 44-year-old man presented with fever and dyspnea of 1 month duration. A chest radiograph revealed bilateral multiple wedge shaped consolidations. In addition, the results of a percutaneous needle biopsy for non-resolving pneumonia were compatible with pulmonary vasculitis. Bone marrow biopsy was performed due to the persistence of unexplained anemia and the patient was diagnosed with MDS. We reported a case of secondary vasculitis presenting as non-resolving pneumonia, later diagnosed as paraneoplastic syndrome of undiagnosed MDS. The cytopenia and vasculitis improved after a short course of glucocorticoid treatment, and there was no recurrence despite the progression of underlying MDS.

Pulmonary strongyloidiasis is an uncommon presentation of Strongyloides infection, usually seen in immunocompromised hosts. The manifestations are similar to that of acute exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, the diagnosis of pulmonary strongyloidiasis could be challenging in a COPD patient, unless a high index of suspicion is maintained. Here, we present a case of Strongyloides hyperinfection in a COPD patient mimicking acute exacerbation, who was on chronic steroid therapy.