• Tuberculosis and Respiratory Diseases
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• v.79 no.1
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• pp.22-30
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• 2016

Background: The purpose of this study was to document outcomes following withdrawal of a single inhaler (step-down) in chronic obstructive pulmonary disease (COPD) patients on triple therapy (long-acting muscarinic antagonist and a combination of long-acting ${\beta}2$-agonists and inhaled corticosteroid), which a common treatment strategy in clinical practice. Methods: Through a retrospective observational study, COPD patients receiving triple therapy over 2 years (triple group; n=109) were compared with those who had undergone triple therapy for at least 1 year and subsequently, over 9 months, initiated inhaler withdrawal (step-down group, n=39). The index time was defined as the time of withdrawal in the step-down group and as 1 year after the start of triple therapy in the triple group. Results: Lung function at the index time was superior and the previous exacerbation frequency was lower in the step-down group than in the triple group. Step-down resulted in aggravating disease symptoms, a reduced overall quality of life, decreasing exercise performance, and accelerated forced expiratory volume in 1 second ($FEV_1$) decline ($54.7{\pm}15.7mL/yr$ vs. $10.7{\pm}7.1mL/yr$, p=0.007), but there was no observed increase in the frequency of exacerbations. Conclusion: Withdrawal of a single inhaler during triple therapy in COPD patients should be conducted with caution as it may impair the exercise capacity and quality of life while accelerating $FEV_1$ decline.

• Tuberculosis and Respiratory Diseases
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• v.84 no.3
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• pp.188-199
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• 2021

Background: Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with increased prevalence in the elderly. Telomeres are repetitive DNA sequences found at the end of the chromosome, which progressively shorten as cells divide. Telomere length is known to be a molecular marker of aging. This study aimed to assess the relationship between telomere length and the risk of COPD, lung function, respiratory symptoms, and emphysema index in Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) cohort. Methods: We extracted DNA from the peripheral blood samples of 446 participants, including 285 COPD patients and 161 control participants. We measured absolute telomere length using quantitative real-time polymerase chain reaction. All participants underwent spirometry and quantitative computed tomography scan. Questionnaires assessing respiratory symptoms and the COPD Assessment Test was filled by all the participants. Results: The mean age of participants at the baseline visit was 72.5±7.1 years. Males accounted for 72% (321 participants) of the all participants. The mean telomere length was lower in the COPD group compared to the non-COPD group (COPD, 16.81±13.90 kb; non-COPD, 21.97±14.43 kb). In COPD patients, 112 (75.7%) were distributed as tertile 1 (shortest), 91 (61.1%) as tertile 2 and 82 (55%) as tertile 3 (longest). We did not find significant associations between telomere length and lung function, exacerbation, airway wall thickness, and emphysema index after adjusting for sex, age, and smoking status. Conclusion: In this study, the relationship between various COPD phenotypes and telomere length was analyzed, but no significant statistical associations were shown.

• Tuberculosis and Respiratory Diseases
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• v.61 no.2
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• pp.129-136
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• 2006

Background: To interpret lung function tests, it is necessary to determine the lower limits of normal (LLN) and to derive a consensus on the interpretative algorithm. '0.7 of LLN for the $FEV_1$/FVC' was suggested by the COPD International Guideline (GOLD) for defining obstructive disease. A consensus on a new interpretative algorithm was recently achieved by ATS/ERS in 2005. We evaluated the accuracy of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases, and we also determined the effect of the new algorithm on diagnosing ventilatory defects. Methods: We obtained the age, gender, height, weight, $FEV_1$, FVC, and $FEV_1$/FVC from 7362 subjects who underwent spirometry in 2005 at the Asan Medical Center, Korea. For diagnosing obstructive diseases, the accuracy of '0.7 of LLN for the $FEV_1$/FVC' was evaluated in reference to the $5^{th}$ percentile of the LLN. By applying the new algorithm, we determined how many more subjects should have lung volumes testing performed. Evaluation of 1611 patients who had lung volumes testing performed as well as spirometry during the period showed how many more subjects were diagnosed with obstructive diseases according to the new algorithm. Results: 1) The sensitivity of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases increased according to age, but the specificity was decreased according to age; the positive predictive value decreased, but the negative predictive value increased. 2) By applying the new algorithm, 34.5% (2540/7362) more subjects should have lung volumes testing performed. 3) By applying the new algorithm, 13% (205/1611) more subjects were diagnosed with obstructive diseases; these subjects corresponded to 30% (205/681) of the subjects who had been diagnosed with restrictive diseases by the old interpretative algorithm. Conclusion: The sensitivity and specificity of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases changes according to age. By applying the new interpretative algorithm, it was shown that more subjects should have lung volumes testing performed, and there was a higher probability of being diagnosed with obstructive diseases.

• Tuberculosis and Respiratory Diseases
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• v.42 no.2
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• pp.218-225
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• 1995

Background: Airway resistance(Raw) is measured with the body plethysmograph by displaying the relationship between airflow and alveolar pressure($V/P_A$). If the resistance curve on $V/P_A$ tracing is curved or looped, the estimation of Raw is difficult. This study was designed to examine wheather there is any correlation between the shape of resistance curve and the clinical status and the pulmonary function of patients. Methods: The 146 pulmonary disease patients with increased Raw were included in this study. The shapes of resistance curves on $V/P_A$ tracing with body plethysmograph during quiet breathing were analyzed and compared with pulmonary function. Results: The results were as follows ; 1) The shapes of resistance curves were summarized in 5 categories; type 1: linear, type 2: ovoid, type 3: sigmoid, type 4: scoop, type 5: paisley. The type 3 except 1 case, type 4 and type 5 were found to have loop mainly in expiratory phase. 2) Although the shapes of resistance curves were not typical for specific disease, the resistance curves of acute disease tended to belong to type 1 or 2 and those of chronic airflow obstruction tended to belong to type 3, 4 or 5. But resistance curves of bronchial asthma and destructive lung with tuberculosis showed all types in proportion to degree of airflow obstruction or destruction of parenchyme. 3) In the cases of resistance curves going to type 5 rather than type 1 and those with looping, airflow obstuction tended to be severe and airway resistance and residual volume tended to increase. Conclusions: Analysis of resistance curve on $V/P_A$ tracing measuring airway resistance is helpful for judging degree of airflow obstruction and air trapping. Although the shape of resistance curve is not typical for specific disease, there is a close association between looping and airway obstruction.

• Korean Journal of Radiology
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• v.21 no.7
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• pp.880-890
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• 2020

Objective: Patients with chronic obstructive pulmonary disease (COPD) are known to be at risk of osteoporosis. The purpose of this study was to evaluate the association between thoracic vertebral bone density measured on chest CT (D_Thorax) and clinical variables, including survival, in patients with COPD. Materials and Methods: A total of 322 patients with COPD were selected from the Korean Obstructive Lung Disease (KOLD) cohort. D_Thorax was measured by averaging the CT values of three consecutive vertebral bodies at the level of the left main coronary artery with a round region of interest as large as possible within the anterior column of each vertebral body using an in-house software. Associations between D_Thorax and clinical variables, including survival, pulmonary function test (PFT) results, and CT densitometry, were evaluated. Results: The median follow-up time was 7.3 years (range: 0.1-12.4 years). Fifty-six patients (17.4%) died. D_Thorax differed significantly between the different Global Initiative for Chronic Obstructive Lung Disease stages. D_Thorax correlated positively with body mass index (BMI), some PFT results, and the six-minute walk distance, and correlated negatively with the emphysema index (EI) (all p < 0.05). In the univariate Cox analysis, older age (hazard ratio [HR], 3.617; 95% confidence interval [CI], 2.119-6.173, p < 0.001), lower BMI (HR, 3.589; 95% CI, 2.122-6.071, p < 0.001), lower forced expiratory volume in one second (FEV₁) (HR, 2.975; 95% CI, 1.682-5.262, p < 0.001), lower diffusing capacity of the lung for carbon monoxide corrected with hemoglobin (DL_CO) (HR, 4.595; 95% CI, 2.665-7.924, p < 0.001), higher EI (HR, 3.722; 95% CI, 2.192-6.319, p < 0.001), presence of vertebral fractures (HR, 2.062; 95% CI, 1.154-3.683, p = 0.015), and lower D_Thorax (HR, 2.773; 95% CI, 1.620-4.746, p < 0.001) were significantly associated with all-cause mortality and lung-related mortality. In the multivariate Cox analysis, lower D_Thorax (HR, 1.957; 95% CI, 1.075-3.563, p = 0.028) along with older age, lower BMI, lower FEV₁, and lower DL_CO were independent predictors of all-cause mortality. Conclusion: The thoracic vertebral bone density measured on chest CT demonstrated significant associations with the patients' mortality and clinical variables of disease severity in the COPD patients included in KOLD cohort.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.67-70
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• 2008

Overlap syndrome can be defined as a coexistence of chronic obstructive pulmonary disease (COPD) and sleep apnea-hypopnea syndrome (SAHS). The association of COPD and SAHS has been suspected because of the frequency of both diseases. Prevalence of COPD and SAHS is respectively 10 and 5% of the adult population over 40 years of age. However, a recent study has shown that the prevalence of SAHS is not higher in COPD than in the general population. The coexistence of the two diseases is only due to chance. SAHS does not affect the pathophysiology of COPD and vice versa. Prevalence of overlap syndrome is expected to occur in about 0.5% of the adult population over 40 years of age. Patients with overlap syndrome have a more profound hypoxemia, hypercapnia, and pulmonary hypertension when compared with patients with SAHS alone or usual COPD patients without SAHS. To treat the overlap syndrome, nocturnal noninvasive ventilation (NIV) or nasal continuous positive airway pressure (nCPAP) can be applied with or without nocturnal oxygen supplement.

• Tuberculosis and Respiratory Diseases
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• v.80 no.1
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• pp.11-20
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• 2017

Approximately one in four patients with chronic obstructive pulmonary disease (COPD) have asthmatic features consisting of wheezing, airway hyper-responsiveness or atopy. The Global initiative for Asthma/Globalinitiative for chronic Obstructive Lung Disease committee recently labelled these patients as having asthma-COPD overlap syndrome or ACOS. ACOS also encompasses patients with asthma, ${\geq}40$ years of age, who have been cigarette smokers (more than 5-10 pack years) or have had significant biomass exposure, and demonstrate persistent airflow limitation defined as a post-bronchodilator forced expiratory volume in 1 second ($FEV_1$)/forced vital capacity of <70%. Data over the past 30 years indicate that patients with ACOS have greater burden of symptoms including dyspnea and cough and show higher risk of COPD exacerbations and hospitalizations than those with pure COPD or pure asthma. Patients with ACOS also have increased risk of rapid $FEV_1$ decline and COPD mortality. Paradoxically, experimental evidence to support therapeutic decisions in ACOS patients is lacking because traditionally, patients with ACOS have been systematically excluded from therapeutic COPD and asthma trials to maintain homogeneity of the study population. In this study, we summarize the current understanding of ACOS, focusing on definitions, epidemiology and patient prognosis.

• Journal of Haehwa Medicine
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• v.19 no.2
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• pp.165-171
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• 2011

Objectives: This study analyzed the contents of the research papers of Maekmundong-tang (MMDT). This study was conducted to help development of new clinical application and clinical studies for treating COPD with Oriental medicine. Materials and Methods: We inspected 26 theses and scrutinized their classification, objective diseases, study design, participants, methodological quality of clinical trial. Results: The following results were obtained in this study. 1. The studies of MMDT started in 1989 and have continuously increased, but it decreased recently. 2. The studies were mainly focused on experimental models rather than clinical studies. The topics of studies were mainly relaxation of airway contraction and anti-asthmatic effect. 3. MMDT was showed to have effects on chronic cough and asthma in these papers. Conclusion: MMDT is being used in respiratory disease. However, mechanism study should be conducted at experimental study and more clinical studies on the efficacy of MMDT for chronic respiratory disease are needed.

• Biomolecules & Therapeutics
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• v.12 no.1
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• pp.1-8
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• 2004

In chronic airway inflammatory diseases such as asthma and chronic bronchitis, it has been suggested that matrix metalloproteinases secreted from infiltrating neutrophil contribute the pathogenesis of the disease and have been a focus of intense investigation. We report here that hamster tracheal surface epithelial goblet cells (HTSE cells) produce matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2). Matrix metalloproteinase activities were investigated using [$^3H$]collagen-digestion assay and gelatin zymography. The subtype of matrix metalloproteinases expressed from HTSE cells was MMP-2 (gelatinase A), which was determined by Western blot with various subtype selective anti-matrix metalloproteinase antibodies. The MMP-2 and TIMP-2 cDNAs from HTSE cells were partially cloned by RT-PCR and they reveal more than 90% of sequence homology with those from human, rat and mouse. The collagenolytic activity was increased with the secretory differentiation of the HTSE cell and it was found that zymogen activation was responsible for the increased MMP-2 activity in HTSE cells. The results from the present study suggest that the metaplastic secretory differentiation of airway goblet cells may affect chronic airway inflammatory process by augmenting the zymogen activation of MMP-2.

• Tuberculosis and Respiratory Diseases
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• v.76 no.5
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• pp.226-232
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• 2014

Background: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation and results from environmental factors and genetic factors. Although cigarette smoking is a major risk factor, other environmental exposures can influence COPD. The purpose of this study is to investigate the clinical characteristics of COPD according to the history of environmental exposure. Methods: The study population comprised of 347 subjects with COPD who were recruited from the pulmonary clinics of 14 hospitals within the Korean Obstructive Lung Disease Study Group. We classified environmental exposures according to history of living near factory, and direct exposure history to firewood or briquette. According to living environmental exposures, we compared the frequency of respiratory symptoms, pulmonary function, quality of life, exercise capacity, and computed tomography phenotypes. Results: Thirty-one subjects (8.9%) had history of living near factory, 271 (78.3%) had exposure history to briquette, and 184 (53.3%) had exposure history to firewood. Patients with history of living near a factory had a significantly longer duration of sputum, while patients with exposure to firewood tended to have lower forced expiratory volume in one second, and patients with exposure to briquette tended to have lower six minute walk distance. Conclusion: COPD subjects with the history of living near factory had more frequent respiratory symptoms such as sputum. Our data suggest that environmental exposure may influence clinical phenotype of COPD.