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Hydroxychloroquine has recently received attention as a treatment for COVID-19. However, it may prolong the QTc interval. Furthermore, when hydroxychloroquine is administered concomitantly with other drugs, it can exacerbate the risk of QT prolongation. Nevertheless, the risk of QT prolongation due to drug-drug interactions (DDIs) between hydroxychloroquine and concomitant medications has not yet been identified. To evaluate the risk of QT prolongation due to DDIs between hydroxychloroquine and 118 concurrent drugs frequently used in real-world practice, we analyzed the electrocardiogram results obtained for 447,632 patients and their relevant electronic health records in a tertiary teaching hospital in Korea from 1996 to 2018. We repeated the case–control analysis for each drug. In each analysis, we performed multiple logistic regression and calculated the odds ratio (OR) for each target drug, hydroxychloroquine, and the interaction terms between those two drugs. The DDIs were observed in 12 drugs (trimebutine, tacrolimus, tramadol, rosuvastatin, cyclosporin, sulfasalazine, rofecoxib, diltiazem, piperacillin/tazobactam, isoniazid, clarithromycin, and furosemide), all with a p value of

Interferon (IFN)-γ-inducible chemokines in the CXCR3/ligand axis are involved in cell-mediated immunity and play a significant role in the progression of cancer. We enrolled patients with lung cancer (n = 144) and healthy volunteers as the controls (n = 140). Initial blood samples were collected and concentrations of IFN-γ and IFN-γ-inducible chemokines CXCL9, CXCL10, and CXCL11 were measured using enzyme-linked immunosorbent assay. Of patients with lung cancer, 125 had non-small cell lung cancer (NSCLC) and 19 had small cell lung cancer. The area under the curve (AUC) (95% CI) of CXCL9 was 0.83 (0.80–0.89) for differentiating lung cancer patients from controls. The levels of all the markers were significantly higher in NSCLC patients with stage IV than in those with stages I–III. A Kaplan-Meier survival analysis showed that NSCLC cancer patients with higher levels of all markers showed poorer survival than those with lower levels. In Cox multivariate analysis of patients with NSCLC, independent prognostic factors for overall survival were CXCL9 and CXCL11. CXCL9 was the only independent prognostic factor for cancer-specific survival. Serum IFN-γ-inducible chemokines may be useful as clinical markers of metastasis and prognosis in NSCLC, and CXCL9 levels showed the most significant results.

Background: Hydroxychloroquine has recently received attention as a treatment for COVID-19. However, hydroxychloroquine may prolong the QTc interval, thus increasing the risk of life-threatening arrhythmia. Many patients with COVID-19 have comorbidities, necessitating the use of several drugs simultaneously with hydroxychloroquine. However, the risk of QT prolongation due to drug-drug interactions (DDIs) between hydroxychloroquine and these co-medications has not been identified. Therefore, it is necessary to investigate the risk of QT interval prolongation due to DDIs between hydroxychloroquine and frequently used concurrent drugs.Methods and Results: Using 447,632 patients and 1,040,752 electrocardiograms, we investigated the risk of QT prolongation due to DDIs between hydroxychloroquine and 118 concurrent drugs frequently used in real-world practice. In the analysis, we observed that 11 drugs (trimebutine, tacrolimus, tramadol, rosuvastatin, ciclosporin, sulfasalazine, rofecoxib, diltiazem, piperacillin/tazobactam, and isoniazid) show DDIs with hydroxychloroquine in the direction of QT prolongation.Conclusions: We found 11 drugs that show significant (p

Objectives Biosignal data include important physiological information. For that reason, many devices and systems have been developed, but there has not been enough consideration of how to collect and integrate raw data from multiple systems. To overcome this limitation, we have developed a system for collecting and integrating biosignal data from two patient monitoring systems. Methods We developed an interface to extract biosignal data from Nihon Kohden and Philips monitoring systems. The Nihon Kohden system has a central server for the temporary storage of raw waveform data, which can be requested using the HL7 protocol. However, the Philips system used in our hospital cannot save raw waveform data. Therefore, our system was connected to monitoring devices using the RS232 protocol. After collection, the data were transformed and stored in a unified format. Results From September 2016 to August 2017, we collected approximately 117 patient-years of waveform data from 1,268 patients in 79 beds of five intensive care units. Because the two systems use the same data storage format, the application software could be run without compatibility issues. Conclusions Our system collects biosignal data from different systems in a unified format. The data collected by the system can be used to develop algorithms or applications without the need to consider the source of the data.

Type 2 diabetes mellitus is a major concern globally and well known for increasing risk of complications. However, diabetes complications often remain undiagnosed and untreated in a large number of high-risk patients. In this study based on claims data collected in South Korea, we aimed to explore the diagnostic progression and sex- and age-related differences among patients with type 2 diabetes using time-considered patterns of the incidence of comorbidities that evolved after a diagnosis of type 2 diabetes. This study compared 164,593 patients who met the full criteria for type 2 diabetes with age group-, sex-, encounter type-, and diagnosis date-matched controls who had not been diagnosed with type 2 diabetes. We identified 76,423 significant trajectories of four diagnoses from the dataset. The top 30 trajectories with the highest average relative risks comprised microvascular, macrovascular, and miscellaneous complications. Compared with the trajectories of male groups, those of female groups included relatively fewer second-order nodes and contained hubs. Moreover, the trajectories of male groups contained diagnoses belonging to various categories. Our trajectories provide additional information about sex- and age-related differences in the risks of complications and identifying sequential relationships between type 2 diabetes and potentially complications.

We evaluated new features from biosignals comprising diverse physiological response information to predict the outcome of weaning from mechanical ventilation (MV). We enrolled 89 patients who were candidates for weaning from MV in the intensive care unit and collected continuous biosignal data: electrocardiogram (ECG), respiratory impedance, photoplethysmogram (PPG), arterial blood pressure, and ventilator parameters during a spontaneous breathing trial (SBT). We compared the collected biosignal data’s variability between patients who successfully discontinued MV (n = 67) and patients who did not (n = 22). To evaluate the usefulness of the identified factors for predicting weaning success, we developed a machine learning model and evaluated its performance by bootstrapping. The following markers were different between the weaning success and failure groups: the ratio of standard deviations between the short-term and long-term heart rate variability in a Poincaré plot, sample entropy of ECG and PPG, α values of ECG, and respiratory impedance in the detrended fluctuation analysis. The area under the receiver operating characteristic curve of the model was 0.81 (95% confidence interval: 0.70–0.92). This combination of the biosignal data-based markers obtained during SBTs provides a promising tool to assist clinicians in determining the optimal extubation time.

Background: Cardiovascular disease is the most common cause of death in chronic obstructive pulmonary disease (COPD). However, the impact of cardiovascular comorbidities on the prognosis of COPD is not well known. Objectives: This study was performed to investigate the effects of cardiovascular comorbidities on the prognosis of COPD. Methods: We enlisted 229 patients with COPD who underwent comprehensive cardiac evaluations including coronary angiography and echocardiography at Ajou University Hospital between January 2000 and December 2012. Survival analyses were performed in this retrospective cohort. Results: Kaplan-Meier analyses showed that COPD patients without left heart failure (mean survival = 12.5 ± 0.7 years) survived longer than COPD patients with left heart failure (mean survival = 6.7 ± 1.4 years; p = 0.003), and the survival period of nonanemic COPD patients (mean survival = 13.8 ± 0.8 years) was longer than that of anemic COPD patients (mean survival = 8.3 ± 0.8 years; p < 0.001). The survival period in COPD with coronary artery disease (CAD; mean survival = 11.37 ± 0.64 years) was not different from that in COPD without CAD (mean survival = 11.98 ± 0.98 years; p = 0.703). According to a multivariate Cox regression model, a lower hemoglobin level, a lower left ventricular ejection fraction, and the forced expiratory volume in 1 s (FEV1) were independently associated with higher mortality in the total COPD group (p < 0.05). Conclusions: Hemoglobin levels and left ventricular ejection fraction along with a lower FEV1 were identified as independent risk factors for mortality in COPD patients who underwent comprehensive cardiac evaluations, suggesting that multidisciplinary approaches are required in the care of COPD.

Background: In COPD, coronary artery disease (CAD) is a frequent co-morbidity and cardiovascular disease is the most common cause of death. When coronary angiography was performed, the Gensini score is used for the assessment of CAD severity. This study was performed to evaluate the clinical impact of Gensini score in COPD. Methods: We retrospectively reviewed 191 patients with COPD (male 90.1%, mean age 68.5 ± 8.9 years, smoker 86.2%) who had undergone coronary angiography in Ajou University Hospital from Jan 2000 to Dec 2012. The extent of CAD in the entire coronary arterial tree was assessed by Gensini score. Comparative analyses between high Gensini group (≥4 points; median value or more) and low Gensini group ( Results: High Gensini group was more frequently associated with triple vessel CAD (37.2% vs. 1.0%, p 1 (66.4 ± 16.9 vs 64. 9 ± 19.0, p=0.583) and prevalence of hypertension (59.6% vs. 57.7%, p=0.796) did not differ between two groups. High Gensini group was independently related to triple vessel CAD (OR 3.51, 95% CI 1.77 – 6.94) and myocardial infarction (OR 5.38, 95% CI 1.83 – 15.82). Conclusion: Our data suggest that high Gensini score in COPD was independently associated with cardiac co-morbidities such as triple vessel CAD and myocardial infarction.

Cell-mediated immunity plays an important role in the pathobiology of tuberculosis (TB). The ligands for CXC chemokine receptor 3 (CXCR3) activate the T-helper type 1 lymphocyte pathway. The CXCR3 ligands are reportedly useful clinical markers for the diagnosis and follow-up of TB. The objective of this study was to assess the utility of CXCR3 ligands for evaluating early treatment responses in TB. We recruited 88 patients who underwent antituberculous chemotherapy. The serum levels of interferon (IFN)-γ and the CXCR3 ligands CXCL9 (monokine induced by IFN-γ [MIG]), CXCL10 (IFN-γ-inducible 10-kDa protein [IP-10]), and CXCL11 (IFN-inducible T-cell α chemoattractant [I-TAC]) were measured before and 2 months after the start of treatment. Treatment responses were divided into “fast” and “slow” based on the clinical, radiological, and bacteriological improvement at 2 months. A change in level of 20% or more at 2 months was defined as “significant.” In patients with treatment success, 58 patients exhibited a fast response and 20 patients exhibited a slow response. Treatment failure occurred in 5 patients, and the diagnoses were changed to non-TB diseases in 5 patients. The levels of all CXCR3 ligands significantly decreased in the fast-response group (P

SummaryBackgroundsEpithelial cell apoptosis plays an important role in the pathogenesis of idiopathic interstitial pneumonia (IIP).MethodsSerum levels of caspase-cleaved cytokeratin-18 (M30) were measured in 55 patients with IIP and 34 healthy controls using enzyme-linked immunosorbent assays. The IIP cases included usual interstitial pneumonia (UIP; n = 30), nonspecific interstitial pneumonia (NSIP; n = 15), and cryptogenic organizing pneumonia (COP; n = 10). The radiological scoring was performed based on high-resolution computed tomography (HRCT) findings.ResultsPatients with IIP had higher serum M30 levels than did the control group (178.6 ± 91.5 vs. 113.7 ± 46.8 U/L, p

Beijing strain of Mycobacterium tuberculosis (M. tb) is characterized by a high incidence of transmission, relapse, and drug resistance. This study aimed to determine host immune responses to antigens derived from the Beijing/K strain which has been highly prevalent in tuberculosis (TB) outbreaks in South Korea.We recruited 52 TB patients and 96 healthy subjects comprising 31 individuals with latent TB infection (LTBI) and 65 TB-naïve controls based on QuantiFERON-TB Gold In-Tube (QFT-IT) tests. Blood samples were obtained for diluted whole-blood assays, multiplex bead arrays, ELISpot assays, and HLA typing. Molecular genotyping of M. tb was performed using clinical isolates.Active TB and LTBI groups were differentiated by TNF-α concentrations induced by the Beijing/K strain-derived antigens, MTBK_24790 and MTBK_24800 (P 0.001). MTBK_24800-induced IFN-γ and CXCL10 concentrations discriminated the TB-infected groups from TB-naïve controls (P 0.001). IFN-γ-producing T cells were generated in 87.2% of TB patients in response to MTBK_24800 peptide antigens. The major immunogenic epitope was at C-terminal of the antigen, and predominantly recognized by HLA-DR4 and -DQ4.Measurement of IFN-γ, CXCL10, and TNF-α concentrations induced by MTBK_24790 and MTBK_24800 may contribute to improved diagnosis of TB and vaccine development in regions where the Beijing/K strain is endemic.

Background: The T-helper type 1(Th1) lymphocytes is important in pathogenesis of tuberculosis. So, we evaluated for significance of interferon (IFN)-γ and IFN-inducible chemokines in pleural effusions. Methods: A total of 276 subjects were enrolled. The study population comprised 80 patients with tuberculous effusions, 68 patients with malignant effusions, 53 patients with parapneumonic effusions, 27 patients with transudates, and 48 patients with miscellaneous effusions. In serum and effusion samples from patients with pleural effusions, the levels of IFN-γ, IFN-inducible T-cell alpha chemoattractant (I-TAC) and monokine induced by IFN-γ (MIG) were measured by enzyme-linked immunosorbent assay (ELISA) and the levels of adenosine deaminase (ADA) were measured by colorimetry. Receiver operating characteristic (ROC) analysis was performed. Results: The levels of IFN-γ, I-TAC, MIG and ADA in the pleural effusions were significantly increased in the tuberculous effusions ( p Conclusions: All the IFN-γinducible chemokines along with and ADA showed high discriminating powers for tuberculous effusion, especially IFN-γ in effusion, and MIG in serum. Those chemokines can be useful surrogate markers in diagnosis of pleural effusion.

BACKGROUND The ligands for CXC chemokine receptor 3 (CXCR3) recruit T-helper type 1 cells, which play a major role in cell-mediated immunity in TB. METHODS A total of 409 subjects were enrolled. The study population comprised 186 patients with active TB, 58 patients with non-TB pulmonary diseases, 50 control subjects with a positive interferon (IFN)-γ release assay (IGRA) result, and 115 control subjects with a negative IGRA result. Whole-blood samples were collected using IGRA methodology. After incubation, plasma IFN-γ levels and two CXCR3 ligands, IFN-inducible T-cell α-chemoattractant (I-TAC, CXCL11) and monokine induced by IFN-γ (MIG, CXCL9), were measured by enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) analysis was performed. Sensitivity and specificity were based on cutoff values selected to maximize the Youden index. RESULTS The TB antigen-stimulated levels of IFN-γ, I-TAC, and MIG were significantly increased in the active pulmonary TB group compared with all other groups. From ROC analysis, for the diagnosis of active TB, I-TAC and MIG outperformed IFN-γ in all comparisons with the IGRA-positive and -negative control groups and the non-TB pulmonary disease group. The areas under the curve (95% CI) for differentiating active pulmonary TB from all other groups were 0.893 (0.864-0.924) for IFN-γ, 0.962 (0.946-0.978) for I-TAC, and 0.944 (0.922-0.965) for MIG. Sensitivity and specificity were 90.3% and 90.7%, respectively, for I-TAC; 92.5% and 85.2% for MIG; and 84.9% and 79.8% for IFN-γ. CONCLUSIONS TB antigen-stimulated assays of I-TAC and MIG may be useful surrogate markers in the diagnosis of active pulmonary TB.

article i nfo Purpose: The Sequential Organ Failure Assessment (SOFA) score, originally developed to assess organ failure status, is widely used as a prognostic indicator in intensive care unit patients. Additional prognostic factors, such as age and comorbidities, may complement the predictive performance of the SOFA. Methods: In total, 1049 consecutive patients were enrolled prospectively. SOFA and other admission-based intensive care unit scores were recorded during the first 24 hours. A complemented SOFA (cSOFA) score model was constructed by adding age and comorbidity scores to the original SOFA score, based on logistic regression analysis. The predictive performance was evaluated with regard to hospital mortality by receiver operating characteristics analysis. The Hosmer-Lemeshow goodness-of-fit test was used to assess calibration of the model, and leave-one-out cross-validation was performed. Results: The cSOFA score (maximum 30 points) was calculated as the SOFA score (24 points) + age score (2 points) + comorbidity score (4 points). The cSOFA score model showed satisfactory calibration and cross- validation performance. The AUC (95% CI) of the cSOFA score (0.812 (0.787-0.835)) was higher than the SOFA score (0.743 (0.715-0.769), P b .0001). Conclusion: The performance of the SOFA score to predict hospital mortality can be improved by considering age and comorbidity factors.

Background/Aims: Peroxiredoxin (Prx) belongs to a ubiquitous family of antioxidant enzymes that regulates many cellular processes through intracellular oxidative signal transduction pathways. Silica-induced lung damage involves reactive oxygen species (ROS) that trigger subsequent toxic effects and inflammatory responses in alveolar epithelial cells resulting in fibrosis. Therefore, we investigated the role of Prx in the development of lung oxidant injury caused by silicosis, and determined the implication of ROS in that process. Methods: Lung epithelial cell lines A549 and WI26 were treated with 1% silica for 0, 24, or 48 hours, following pretreatment of the A549 cells with N-acetyl-L-cysteine and diphenylene iodonium and no pretreatment of the WI26 cells. We transfected an HA-ubiquitin construct into the A549 cell line and then analyzed the cells via Western blotting and co-immunoprecipitation. Results: Silica treatment induced cell death in the A549 lung epithelial cell line and selectively degraded Prx I without impairing protein synthesis in the A549 cells, even when the ROS effect was blocked chemically by Nacetyl-L-cysteine. A co-immunoprecipitation study revealed that Prx I did not undergo ubiquitination. Conclusions: Silica treatment induces a decrease of Prx I expression in lung epithelial cell lines regardless of the presence of ROS. The silica-induced degradation of Prx does not involve the ubiquitin-proteasomal pathway. (Korean J Intern Med 2009;24:220-226)

Received: December 24, 2013Revised: April 17, 2014Accepted: April 18, 2014Corresponding author: Dr. Min Kwang Byun, Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 135-720, Korea.Tel: 82-2-2019-3454, Fax: 82-2-3463-3882E-mail: littmann@yuhs.ac∙ The authors have no financial conflicts of interest.

Background: Apoptosis plays a role in the development of pleural effusion. Caspase-cleaved cytokeratin 18, a marker for epithelial cell apoptosis, was evaluated in pleural effusion. Methods: A total of 79 patients with pleural effusion were enrolled. The underlying causes were lung cancer (n=24), parapneumonic effusion (n=15), tuberculous effusion (n=28), and transudates (n=12). The levels of M30, an epitope of caspase-cleaved cytokeratin 18, were measured in blood and pleural fluids using enzyme-linked immunosorbent assay along with routine cellular and biochemical parameters. The expression of M30 was evaluated in the pleural tissues using immunohistochemistry for M30. Results: The M30 levels in pleural fluid were significantly higher in patients with tuberculosis (2,632.1±1,467.3 U/mL) than in patients with lung cancer (956.5±618.5 U/mL), parapneumonic effusion (689.9±413.6 U/mL), and transudates (273.6±144.5 U/mL; all p

Background: Adequate assessment and control of sedation play crucial roles in the proper performance of mechanical ventilation. Methods: A total of 30 patients with various pulmonary diseases were prospectively enrolled. The study population was randomized into two groups. The sedation assessment group (SAG) received active protocol-based control of sedation, and in the empiric control group (ECG), the sedation levels were empirically adjusted. Subsequently, daily interruption of sedation (DIS) was conducted in the SAG. Results: In the SAG, the dose of midazolam was significantly reduced by control of sedation (day 1, 1.3±0.5 μg/kg/min; day 2, 0.9±0.4μg/kg/min; p＜0.01), and was significantly lower than the ECG on day 2 (p＜0.01). Likewise, on day 2, sedation levels were significantly lower in the SAG than in the ECG. Significant relationship was found between Ramsay sedation scale and Richmond agitation-sedation scale (RASS; rs=−0.57), Ramsay Sedation Scale and Bispectral Index (BIS; rs=0.77), and RASS and BIS (rs=−0.79). In 10 patients, who didn't require re-sedation after DIS, BIS showed the earliest and most significant changes among the sedation scales. Ventilatory parameters showed significant but less prominent changes, and hemodynamic parameters didn't show significant changes. No seriously adverse events ensued after the implementation of DIS. Conclusion: Active assessment and control of sedation significantly reduced the dosage of sedatives in patients receiving mechanical ventilation. DIS, conducted in limited cases, suggested its potential efficacy and tolerability.

Background: Adaptive support ventilation (ASV), an automated closed-loop ventilation mode, adapts to the mechanical characteristics of the respiratory system by continuous measurement and adjustment of the respiratory parameters. The adequacy of ASV was evaluated in the patients with acute lung injury (ALI). Methods: A total of 36 patients (19 normal lungs and 17 ALIs) were enrolled. The patients' breathing patterns and respiratory mechanics parameters were recorded under the passive ventilation using the ASV mode. Results: The ALI patients showed lower tidal volumes and higher respiratory rates (RR) compared to patients with normal lungs (7.1±0.9 mL/kg vs. 8.6±1.3 mL/kg IBW; 19.7±4.8 b/min vs. 14.6±4.6 b/min; p＜0.05, respectively). The expiratory time constant (RCe) was lower in ALI patients than in those with normal lungs, and the expiratory time/RCe was maintained above 3 in both groups. In all patients, RR was correlated with RCe and peak inspiratory flow ( rs=−0.40; rs=0.43; p＜0.05, respectively). In ALI patients, significant correlations were found between RR and RCe (rs=−0.76, p＜0.01), peak inspiratory flow and RR (rs=−0.53, p＜0.05), and RCe and peak inspiratory flow (rs=−0.53, p＜0.05). Conclusion: ASV was found to operate adequately according to the respiratory mechanical characteristics in the ALI patients. Discrepancies with the ARDS Network recommendations, such as a somewhat higher tidal volume, have yet to be addressed in further studies.

BACKGROUND/AIMS Oxidative stress results in protein oxidation and is implicated in carcinogenesis. Sulfiredoxin (Srx) is responsible for the enzymatic reversal of inactivated peroxiredoxin (Prx). Nuclear factor E2-related factor 2 (Nrf2) binds to antioxidant responsive elements and upregulates the expression of Srx and Prx during oxidative stress. We aimed to elucidate the biological functions and potential roles of Srx in lung cancer. METHODS To study the roles of Srx and Prx III in lung cancer, we compared the protein levels of Nrf2, Prxs, thioredoxin, and Srx in 40 surgically resected human lung cancer tissues using immunoblot and immunohistochemical analyses. Transforming growth factor-β(1), tumor necrosis factor-α, and camptothecin treatment were used to examine Prx III inactivation in Mv1Lu mink lung epithelial cells and A549 lung cancer cells. RESULTS Prx I and Prx III proteins were markedly overexpressed in lung cancer tissues. A significant increase in the oxidized form of a cysteine sulfhydryl at the catalytic site of Prxs was found in carcinogenic lung tissue compared to normal lung tissue. Densitometric analyses of immunoblot data revealed significant Srx expression, which was higher in squamous cell carcinoma tissue (60%, 12/20) than in adenocarcinoma (20%, 4/20). Also, Nrf2 was present in the nuclear compartment of cancer cells. CONCLUSIONS Srx and Prx III proteins were markedly overexpressed in human squamous cell carcinoma, suggesting that these proteins may play a protective role against oxidative injury and compensate for the high rate of mitochondrial metabolism in lung cancer.

Angiosarcoma is a rare but highly malignant tumorthat usually arises in the scalp or face of elderly males. Distant metastases favor the lung, liver, lymph nodes and skin. Metastatic pulmonary angiosarcoma commonly takes the form of a nodule but can sometimes appear as a thin-walled cyst. We report a case of 65 years-old male with a spontaneous pneumothorax, who underwent excision and radiotherapy for an angiosarcoma of the scalp 2 years ago. A chest CT scan revealed multiple cysts in the lung. The video-assisted thoracoscopic lung biopsy demonstrated subpleural cysts without tumor cells. A skin biopsy of the scalp showed an angiosarcoma. This case was diagnosed as a recurrence of an angiosarcoma with a supposed lung metastasis. This case suggests that a spontaneous pneumothorax in elderly people may be secondary to a pulmonary metastasis from an angiosarcoma of the scalp.

Bronchiolitis obliterans organizing pneumonia (BOOP) is often diagnosed in patients with pneumonia who respond poorly to antibiotics. BOOP is often idiopathic, and the etiology of the remaining cases has been attributed to a wide range of agents or medical conditions. When a patient develops the clinical symptoms characteristic of BOOP, the medical team must endeavor to determine the etiology of this disease because it can be treated with glucocorticoid and avoidance of the causative agent. In particular, if BOOP is diagnosed during or after chemotherapy for a malignancy, the possible culprit agent can be the anti cancer drugs but other drugs used for supportive care must be also be considered. We report a case of BOOP that arose after CHOP chemotherapy and a filgrastim injection in a patient with a diffuse large B-cell lymphoma.

Lung cancer is a leading cause of cancer-related death in the world. Smoking is definitely the most important risk factor for lung cancer. Radon ((222)Rn) is a natural gas produced from radium ((226)Ra) in the decay series of uranium ((238)U). Radon exposure is the second most common cause of lung cancer and the first risk factor for lung cancer in never-smokers. Case-control studies have provided epidemiological evidence of the causative relationship between indoor radon exposure and lung cancer. Twenty-four case-control study papers were found by our search strategy from the PubMed database. Among them, seven studies showed that indoor radon has a statistically significant association with lung cancer. The studies performed in radon-prone areas showed a more positive association between radon and lung cancer. Reviewed papers had inconsistent results on the dose-response relationship between indoor radon and lung cancer risk. Further refined case-control studies will be required to evaluate the relationship between radon and lung cancer. Sufficient study sample size, proper interview methods, valid and precise indoor radon measurement, wide range of indoor radon, and appropriate control of confounders such as smoking status should be considered in further case-control studies.