The extremely low frequency-electromagnetic field (ELF-EMF) refers to the frequency range of 0-300 Hz. It has been reported that it causes biological effects on cell survival, growth, and function. Structural changes were observed in the cell membranes of bacteria exposed to a certain intensity of ELF-EMF, indicating that exposure of bacteria to ELF-EMF can directly affect the cell membrane and affect the survival and growth of bacteria. The purpose of this study was to investigate the effect of the application of low frequency square wave positive voltages on Aggregatibactor actinomycetemcomitans (A. actinomycetemcomitans), a putative pathogen of periodontal disease. A square wave positive voltage output of 20 V or less at low frequency (0-300 Hz) was applied to A. actinomycetemcomitans in a range of 60 minutes. Changes in the population of bacteria were observed by absorbance measurement, colony forming unit (CFU/ml) evaluation, and high-resolution field-emission scanning electron microscopy (HR FE-SEM). The results show that the most effective offset and frequency in inhibiting bacterial growth are 0.7V and 7.83 Hz (Schumann resonance). As the applied time increased and the voltage increased, it was effective in inhibiting bacterial growth. These results led to the conclusion that bacterial growth can be inhibited even at low frequencies below 10 Hz, and it was experimentally proven that the frequency, voltage setting, and exposure time of ELF-EMF have a significant effect on reducing the growth of A. actinomycetemcomitans.

Purpose: Resectable pancreatic ductal adenocarcinoma (PDAC) has a high risk of recurrence after curative resection; despite this, the preoperative risk factors for predicting early recurrence remain unclear. This study therefore aimed to identify preoperative inflammation and nutrition factors associated with early recurrence of resectable PDAC. Methods: From March 2021 to November 2021, a total of 20 patients who underwent curative resection for PDAC were enrolled in this study. We evaluated the risk factors for early recurrence within 1 year by univariate and multivariate analyses using Cox hazard proportional regression. The cutoff values for predicting recurrence were examined using receiver operating characteristic (ROC) curves. Results: In our univariate and multivariate analyses, C-reactive protein (CRP), CRP-albumin ratio, and CRP-prealbumin ratio, as well as sex and age, were significant independent prognostic factors for early recurrence in PDAC. However, known inflammatory factors (neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios), nutritional factors (albumin, prealbumin, ferritin, vitamin D), and inflammatory-nutritional factors (Glasgow Prognostic Score, modified Glasgow Prognostic Score, albumin-bilirubin) showed no association with early recurrence. In addition, using cutoff values by ROC curve analysis, a high preoperative CRP level of >5 mg/L, as well as high CRP-to-albumin (>5.3) and CRP-to-prealbumin (>1.3) ratios showed no prognostic value. Conclusion Our results showed that inflammatory and perioperative nutritional factors, especially CRP-to-prealbumin ratio, have significant associations with early recurrence after curative resection in resectable PDAC. Therefore, for such patients, a cautious approach is needed when inflammation and poor nutritional status are present.

Background: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) update 2023 proposed new definitions of chronic obstructive pulmonary disease (COPD) and COPD exacerbation. However, an agreement on the definitions has not been made, either internationally or domestically. This study aimed to reach an agreement between experts on the new definitions of COPD and COPD exacerbation in South Korea. Methods: A modified Delphi method was used to make an agreement on the definitions of COPD and COPD exacerbation proposed by the GOLD update 2023. We performed two rounds of the survey including 15 Korean experts on COPD, asthma, and tuberculosis. Results: More than two-thirds of the experts agreed on 12 of the 13 statements related to the definitions of COPD and COPD exacerbation in the two rounds of the survey. The experts agreed on the definitions of COPD and COPD exacerbation that should be revised in line with the definitions proposed by the GOLD update 2023. However, the experts showed an uncertain opinion on the statement that the definition of COPD includes patients with persistent airflow obstruction due to bronchiectasis. Conclusion Based on this Delphi survey, experts’ agreement was made on the definitions of COPD and COPD exacerbation proposed by the GOLD update 2023.

Background: Because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities, this study aimed to develop a diagnostic bundle for bronchiectasis in South Korea. Methods: A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initial statements proposed by a core panel, based on international bronchiectasis guidelines, were discussed in an online meeting and two email surveys by a panel of experts (≥70% agreement). Results: The study involved 21 expert participants, and 30 statements regarding a diagnostic bundle for bronchiectasis were classified as recommended, conditional, or not recommended. The consensus statements of the expert panel were as follows: A standardized diagnostic bundle is useful in clinical practice; diagnostic tests for specific diseases, including immunodeficiency and allergic bronchopulmonary aspergillosis, are necessary when clinically suspected; initial diagnostic tests, including sputum microbiology and spirometry, are essential in all patients with bronchiectasis, and patients suspected with rare causes such as primary ciliary dyskinesia should be referred to specialized centers. Conclusion Based on this Delphi survey, expert consensus statements were generated including specific diagnostic, laboratory, microbiological, and pulmonary function tests required to manage patients with bronchiectasis in South Korea.

Background: Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods: A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma–COPD (ACO) and pure COPD was performed. Results: We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.

Purpose: Although metformin and sildenafil can protect various organs against ischemia/reperfusion (I/R) injuries, their effects and mechanisms of action in bladder I/R injuries remain unknown. This study investigated the effects and mechanisms of action of metformin and sildenafil against bladder I/R insults in rats. Methods: One hundred male Sprague-Dawley rats were randomly divided into 5 groups, each of which contained 20 rats: a sham-operated group, a bladder I/R group, and bladder I/R groups treated with metformin, sildenafil, or both agents. Ischemia was induced by clamping the bilateral common iliac arteries with atraumatic vascular clamps for 2 hours, followed by reperfusion for 7 days. During this period, rats were injected once daily with 4-mg/kg metformin and/or 1-mg/kg sildenafil. Results: I/R injuries induced increased malondialdehyde levels and myeloperoxidase activity and decreased superoxide dismutase activity. These changes were attenuated by treatment with metformin and/or sildenafil. The I/R group had significantly higher Jun N-terminal kinase, p38 mitogen-activated protein kinase (MAPK), Bax, caspase-3, and nuclear factor-kappa B (NF-κB) levels, and lower extracellular signal-regulated kinase, and Bcl-2 levels in the bladder than the sham-operated group; these changes were significantly ameliorated by metformin and/or sildenafil treatment. No differences in the levels of these markers were observed between rats coadministered metformin and sildenafil and those treated with either agent alone. Conclusions Metformin and sildenafil protected the rat bladder against I/R injuries. This effect may have been due to the inhibition of reactive oxygen species production through MAPK, Bax, and Bcl-2 activation, and the restoration of inflammation through NF-κB inhibition. However, the combination of metformin and sildenafil was not more effective than either agent alone.

BACKGROUND: Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. METHODS: This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. RESULTS: The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. CONCLUSION: This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.
Delivery of Health Care ; Efficiency ; Health Care Costs ; Humans ; Korea* ; Nursing ; Pulmonary Disease, Chronic Obstructive*

BACKGROUND: Smoking cessation is the most powerful intervention to modify progress of chronic obstructive pulmonary disease (COPD), and nicotine dependence is one of the most important determinants of success or failure in smoking cessation. We evaluated nicotine dependence status and investigated factors associated with moderate to high nicotine dependence in patients with COPD. METHODS: We included 53 current smokers with COPD in the Korean Obstructive Lung Disease II cohort enrolled between January 2014 and March 2016. Nicotine dependence was measured by using Fagerstrom test for nicotine dependence (FTND). Cognitive function was assessed by Korean version of Montreal Cognitive Assessment. RESULTS: The median FTND score was 3, and 32 patients (60%) had moderate to high nicotine dependence. The median smoking amount was 44 pack-years, which was not related to nicotine dependence. Multiple logistic regression analysis revealed that high education status (odds ratio, 1.286; 95% confidence interval, 1.036–1.596; p=0.023), age <70 (odds ratio, 6.407; 95% confidence interval, 1.376–29.830; p=0.018), and mild to moderate airflow obstruction (odds ratio, 6.969; 95% confidence interval, 1.388–34.998; p=0.018) were related to moderate to high nicotine dependence. CONCLUSION: Nicotine dependence does not correlate with smoking amount, but with education level, age, and severity of airflow obstruction. Physicians should provide different strategies of smoking cessation intervention for current smokers with COPD according to their education levels, age, and severity of airflow obstruction.
Cognition ; Cohort Studies ; Education ; Humans ; Logistic Models ; Lung Diseases, Obstructive ; Nicotine* ; Pulmonary Disease, Chronic Obstructive* ; Smoke ; Smoking ; Smoking Cessation ; Tobacco Use Disorder*

OBJECTIVE: The aim of this study is to describe the clinical characteristics and outcome of cancer diagnosed during pregnancy. METHODS: This is a retrospective cohort study of women who were diagnosed with cancer during pregnancy at a tertiary academic hospital between 1995 and 2013. Maternal characteristics, gestational age at diagnosis, and type, stage, symptoms and signs of cancer for each patient were retrieved from the medical records. The cancer treatment, pregnancy management and the subsequent perinatal and maternal outcomes for each cancer were assessed. RESULTS: A total of 87 women were diagnosed with cancer during pregnancy (172.6 cases per 100,000 deliveries). The most common cancer was breast cancer (n=20), followed by gastrointestinal (n=17), hematologic (n=13), thyroid (n=11), central nervous system (n=7), cervical (n=7), ovarian (n=5), lung (n=3), and other cancers (n=4). Eighteen (20.7%) patients terminated their pregnancies. In the 69 (79.3%) patients who maintained their pregnancies, one patient miscarried and 34 patients delivered preterm. Of the preterm babies, 24 (70.6%) were admitted to the neonatal intensive care unit and 3 (8.8%) of those expired. The maternal mortality rate was 31.0%, with highest rate seen with lung cancers (66.7%), followed by gastrointestinal (50.0%), central nervous system (50.0%), hematologic (30.8%), breast (25.0%), ovarian (20.0%) cervical (14.3%), and thyroid cancers (0%). CONCLUSION: The clinical characteristics and outcome of cancer during pregnancy were highly variable depending on the type of cancer. However, timely diagnosis and appropriate management of cancer during pregnancy may improve both maternal and neonatal outcome.
Breast ; Breast Neoplasms ; Central Nervous System ; Cohort Studies ; Diagnosis ; Female ; Gestational Age ; Humans ; Infant, Newborn ; Intensive Care, Neonatal ; Lung ; Lung Neoplasms ; Maternal Mortality ; Medical Records ; Pregnancy Outcome ; Pregnancy* ; Retrospective Studies ; Thyroid Gland

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 beta2-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 stepdown 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 stepdown 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 (FEV1) decline (54.7+/-15.7 mL/yr vs. 10.7+/-7.1 mL/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 FEV1 decline.
Forced Expiratory Volume ; Humans ; Lung ; Lung Diseases ; Nebulizers and Vaporizers* ; Observational Study ; Pulmonary Disease, Chronic Obstructive* ; Quality of Life ; Retrospective Studies