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.

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.

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: 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/AIMS: Pancreatic cancer has a very poor prognosis, and early diagnosis is a way to increase the survival rate of patients. The purpose of this study was to develop pancreatic cancer-specific peptides for imaging studies. METHODS: Three pancreatic cancer cell lines, MIA PaCa-2, UACC-462, and BxPC-3, and a control cell line, CCD841, were used. Biopannings were performed on MIA PaCa-2 using a phage display library. After this, the peptides were synthesized and labeled with fluorescein isothiocyanate (FITC). Immunocytochemistry (ICC), enzyme-linked immunosorbent assay (ELISA), and fluorescence-activated cell sorter (FACS) were performed to examine the specific binding. To examine its therapeutic applications, a photosensitizer, chlorin e6 (Ce6), was conjugated on the peptide and photodynamic therapy was performed. Cell survival was investigated using a [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay. RESULTS: After three biopannings, the phages were amplified from 1.4×104 to 3.2×105 plaque-forming units. The most strongly binding phage was selected from the ELISA and ICC results. FITC-labeled peptide, M5, in the three pancreatic cancer cell lines showed significantly higher immunofluorescence in the ICC experiments than that of CCD841. The higher binding ability to MIA PaCa-2 cells was confirmed from FACS analysis, which showed a right shift compared to CCD841. M5 bound to Ce6 showed a significantly lower cell survival rate than that of Ce6 alone in photodynamic therapy, which was observed consistently as a change in the tumor size and fluorescence intensity in MIA PaCa-2 cell-implanted animal models. CONCLUSIONS: This study showed that the noble peptide, M5, binds specifically to the pancreatic cancer cell line, MIA PaCa-2. The M5 peptide has potential use in future optical diagnostic and therapeutic purposes.
Bacteriophages ; Cell Line ; Cell Survival ; Early Diagnosis ; Enzyme-Linked Immunosorbent Assay ; Fluorescein ; Fluorescence ; Fluorescent Antibody Technique ; Humans ; Immunohistochemistry ; Models, Animal ; Pancreatic Neoplasms ; Peptides ; Photochemotherapy ; Prognosis ; Survival Rate

BACKGROUND/AIMS: Pancreatic cancer has a very poor prognosis, and early diagnosis is a way to increase the survival rate of patients. The purpose of this study was to develop pancreatic cancer-specific peptides for imaging studies.METHODS: Three pancreatic cancer cell lines, MIA PaCa-2, UACC-462, and BxPC-3, and a control cell line, CCD841, were used. Biopannings were performed on MIA PaCa-2 using a phage display library. After this, the peptides were synthesized and labeled with fluorescein isothiocyanate (FITC). Immunocytochemistry (ICC), enzyme-linked immunosorbent assay (ELISA), and fluorescence-activated cell sorter (FACS) were performed to examine the specific binding. To examine its therapeutic applications, a photosensitizer, chlorin e6 (Ce6), was conjugated on the peptide and photodynamic therapy was performed. Cell survival was investigated using a [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay.RESULTS: After three biopannings, the phages were amplified from 1.4×104 to 3.2×105 plaque-forming units. The most strongly binding phage was selected from the ELISA and ICC results. FITC-labeled peptide, M5, in the three pancreatic cancer cell lines showed significantly higher immunofluorescence in the ICC experiments than that of CCD841. The higher binding ability to MIA PaCa-2 cells was confirmed from FACS analysis, which showed a right shift compared to CCD841. M5 bound to Ce6 showed a significantly lower cell survival rate than that of Ce6 alone in photodynamic therapy, which was observed consistently as a change in the tumor size and fluorescence intensity in MIA PaCa-2 cell-implanted animal models.CONCLUSIONS: This study showed that the noble peptide, M5, binds specifically to the pancreatic cancer cell line, MIA PaCa-2. The M5 peptide has potential use in future optical diagnostic and therapeutic purposes.
Bacteriophages ; Cell Line ; Cell Survival ; Early Diagnosis ; Enzyme-Linked Immunosorbent Assay ; Fluorescein ; Fluorescence ; Fluorescent Antibody Technique ; Humans ; Immunohistochemistry ; Models, Animal ; Pancreatic Neoplasms ; Peptides ; Photochemotherapy ; Prognosis ; Survival Rate

In the present study, we identified a Spirometra species of Myanmar origin (plerocercoid) by molecular analysis using mitochondrial cox1 and nad1 genes, as well as by morphological observations of an adult tapeworm. Spargana specimens were collected from a paddy-field in Taik Kyi Township Tarkwa Village, Yangon, Myanmar in December 2017. A total of 5 spargana were obtained from 20 frogs Hoplobatrachus rugulosus; syn: Rana rugulosa (Wiegmann, 1834) or R. tigrina (Steindachner, 1867). The plerocercoids were used for experimental infection of a dog. After 4 weeks of infection, an adult tapeworm was recovered from the intestine of the dog. Morphologically, the distinct features of Spirometra sp. (Myanmar origin) relative to S. erinaceieuropaei and S. decipiens include a uterine morphology comprising posterior uterine coils that larger than the terminal uterine ball and coiling of the uteri diagonally (swirling) rather than spirally. The cox1 sequences (1,566 bp) of the Myanmar-origin Spirometra species showed 97.9% similarity to a reference sequence of S. decipiens (GenBank no. KJ599679) and 90.5% similarity to a reference sequence of S. erinaceieuropaei (GenBank no. KJ599680). Phylogenetic tree topologies were identical and presented high confidence level of values for the 3 major branches of the 3 Spirometra species in cox1 and nad1 genes. These results indicated that Myanmar-origin Spirometra species coincided with those of S. ranarum and may be considered as a valid species.
Adult ; Animals ; Cestoda ; Dogs ; Genes, vif ; Humans ; Intestines ; Myanmar ; Ranidae ; Spirometra ; Trees ; Uterus