• Pediatric Infection and Vaccine
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• v.27 no.3
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• pp.158-170
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• 2020

Purpose: We evaluated the incidence and characteristics of Clostridioides difficile infection (CDI) in Korean children. Methods: Medical records of patients aged 2-18 years and diagnosed with CDI at a tertiary hospital between 2009 and 2018 were analyzed. The patients were classified into three CDI groups: community-acquired (CA), community onset-health care facility-associated (CO-HCFA), and healthcare facility onset (HO). Results: The incidence of CDI increased from 1.00 to 10.01 cases per 10,000 admissions from 2009 to 2018 (P<0.001). As compared to the CA group, the HO group had a higher frequency of operation and malignancy as predisposing factors (40.4% vs. 0.0%, P=0.001; and 27.7% vs. 0.0%, P=0.027, respectively), frequency and number of previous antibiotic use (97.9% vs. 31.3%, P<0.001; and 2 vs. 0, P<0.001, respectively), and median postdiagnosis hospital stay (13 vs. 5 days, P=0.008). The CO-HCFA group had a lower median age and higher frequency of malignancy than the CA group (5 vs. 13 years, P=0.012; and 30.8% vs. 0.0%, P=0.030, respectively). As compared to the HO group, the CA group had a higher frequency of abdominal pain and hematochezia (56.3% vs. 10.6%, P=0.001; and 50.0% vs. 10.6%, P=0.002, respectively), inflammatory bowel disease (68.8% vs. 2.1%, P=0.001), and intravenous metronidazole treatment (37.5% vs. 2.1%, P=0.001). Conclusions: With the increasing incidence of pediatric CDI, awareness regarding its epidemiology and clinical characteristics is important to manage nosocomial infections.

• Food Science and Industry
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• v.53 no.1
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• pp.2-32
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• 2020

In recent years, significant importance has been given to chitooligosaccharides (COS) due to its potent notable biological applications. COS can be derived from chitosan which is commonly produced by partially hydrolyzed products from crustacean shells. In order to produce COS, there are several approaches including chemical and enzymatic methods which are the two most common choices. In this regard, several new methods were intended to be promoted which use the enzymatic hydrolysis with a lower cost and desired properties. Hence, the dual reactor system has gained more attention than other newly developed technologies. Enzymatic hydrolysis derived COS possesses important biological activities such as anticancer, antioxidant, anti-hypersentive, anti-dementia (Altzheimer's disease), anti-diabeties, anti-allergy, anti-inflammatory, etc. Results strongly suggest that properties of COS can be potential materials for nutraceutical, pharmaceutical, and cosmeceutical product development.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.75-82
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• 2024

Purpose: As the coronavirus disease 2019 (COVID-19) pandemic ended, the number of patients with respiratory syncytial virus (RSV) pneumonia increased during the spring/summer of 2022. This study aimed to analyze the clinical features and antibiotic usage of children hospitalized for RSV pneumonia in a recently established general hospital in Sejong city. Methods: In this retrospective review, we included inpatients of the Pediatric Department of Chungnam National University Sejong Hospital diagnosed with RSV pneumonia between March 2022 and April 2023. Patients were divided into 2 groups: with and without antibiotic treatment. Demographic data, initial presentations, and clinical courses were reviewed. Results: A total of 116 patients with RSV pneumonia were hospitalized during this period, of which 102 were analyzed, excluding 14 with underlying diseases or who did not fall within the definition of pneumonia. The median age was 17 months. Diagnoses of bacterial infections (acute otitis media and sinusitis) were documented in 9.8% of cases. Intravenous (IV) antibiotics were administered in 46% of cases. The group receiving IV antibiotics showed higher inflammatory levels (C-reactive protein; CRP), more infiltration on initial chest X-rays, and longer fever duration. There was no difference in the length of hospitalization between the groups with and without IV antibiotics. Conclusions: This study showed a tendency for the attending physician to prescribe IV antibiotics to patients with longer fever duration, pulmonary infiltrations on the initial chest X-ray, and higher CRP levels. However, given the high rate of IV antibiotic usage compared to previous studies, care should be taken in antibiotic use.

• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.691-702
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• 2000

Background : Acute lung injury (ALI) is a commonly encountered respiratory disease and its prognosis is poor when the treatment is not provided promptly and properly. However no specific pharmacologic treatment is currently available for ALI, although recently several supportive drugs have been under scrutiny. We studied anti-inflammatory effects of pentoxifylline (PF), a methylated xanthine, and ONO-5046, a synthetic neutrophil elastase inhibitor on lipopolysaccharide (LPS)-induced ALI in vitro. Methods : To establish an in vitro model of LPS-induced ALI, primary rat alveolar macrophages and peripheral neutrophils in various ratios (1:0, 5:1, 1:1, 1:5, 0:1) were co-cultured with transformed rat alveolar epithelial cells (L2 cell line) or vascular endothelial cells (IP2-E4 cell line) under LPS stimulation. Each experiment was divided into five groups-control, LPS, LPS+PF, LPS+ONO, and LPS+PF+ONO. We compared LPS-induced superoxide anion productions from primary rat alveolar macrophages and peripheral neutrophils in various ratios, and the resultant cytotoxicity on L2 cells or IP2-E4 cells between groups. In addition we also compared the productions of tumor necrosis factor (TNF)-$\alpha$ interleukin (IL)-$1{\beta}$, monocyte chemotactic protein(MCP)-1, IL-6, and IL-10 as well as mRNA expressions of TNF-$\alpha$ inducible nitric oxide synthetase(iNOS), and MCP-1 from LPS-stimulated primary rat alveolar macrophages between groups. Results : (1) PF and ONO-5046 in each or both showed a trend to suppress LPS-induced superoxide anion productions from primary rat alveolar macrophages and peripheral neutrophils regardless of their ratio, except for the LPS+PF+ONO group with the 1:5 ratio, although statistical significance was limited to a few selected experimental conditions. (2) PF and ONO-5046 in each or both showed a trend to prevent IP2-E4 cells from LPS-induced cytotoxicity by primary rat alveolar macrophages and peripheral neutrophils regardless their ratio, although statistical significance was limited to a few selected experimental conditions. the effects of PF and/or ONO-5046 on LPS-induced L2 cell cytotoxicity varied according to experimental conditions. (3) PF showed a trend to inhibit LPS-induced productions of INF-$\alpha$ MCP-1, and IL-10 from primary rat alveolar macrophages. ONO-5046 alone didnot affect the LPS-induced productions of proinflammatory cytokines from primary rat alveolar macrophages but the combination of PF and ONO-5046 showed a trend to suppress LPS-induced productions of INF-$\alpha$ and IL-10 PF and ONO-5046 in each or both showed a trend to increase LPS-induced IL-$\beta$ and IL-6 productions from primary rat alveolar macrophages. (4) PF and ONO-5046 in each or both showed a trend to attenuate LPS-induced mRNA expressions of TNF-$\alpha$ and MCP-1 from primary rat alveolar macrophages but at the same time showed a trend increase iNOS mRNA expression. Conclusion : These results suggest that PF and ONO-5046 may play a role in attenuating inflammation in LPS-induced ALI and that further study is needed to use these drugs as a new supportive therapeutic strategy for ALI.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.175-184
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• 1999

Background: Bronchial asthma is characterized by chronic eosinophilic inflammatory airway disease associated with bronchial hyperresponsiveness and reversible airway obstruction. Bronchial inflammation in asthma may depend in part on the activation of T helper lymphocytes that elaborate proinflammatory cytokines. T helper (Th) lymphocytes can be divided into two categories; Th1 lymphocytes, which secrete IL-2, IL-12 and IFN-$\gamma$, and Th2 lymphocytes, which secrete IL-4, IL-5, IL-6 and IL-10. Th2 lymphocytes appear to induce allergic responses, whereas Th1 lymphocytes induce delayed-type hypersensitivity response. Some infections, such as tuberculosis, cultivate a Th1 immunological environment and inhibit Th2 lymphocytes function. The presence of such infections might inhibit Th2 immune responses and thus protect development of atopic diseases. Method: 15 patients with allergic bronchial asthma, 10 patients with intrinsic bronchial asthma, and 10 healthy volunteers were studied. The serum concentrations of IFN-$\gamma$, IL-12, IL-4, IL-5, and IL-10 were measured by ELISA method and tuberculin skin test was estimated in different groups. Results: The positive response rates of tuberculin test were 46.7% in patients with allergic asthma, 100% in patients with intrinsic asthma and 60% in normal controls. The positive response rates were significantly lower in patients with allergic asthma than those of in patients with intrinsic asthma (p<0.05). Degree of responses to tuberculin test were $12.0{\pm}9.6mm$ in patients with allergic asthma, $18.4{\pm}4.5mm$ in patients with intrinsic asthma and $10.9{\pm}8.8mm$ in normal controls. The degree of responses were significantly reduced in patients with allergic asthma than those of patients with intrinsic asthma (p<0.05). The serum levels of IL-5 in patients with allergic asthma were significantly higher than in patients with intrinsic asthma and normal controls (p<0.05), although it was insignificant. the serum levels of IL-4 and IL-10 in patients with allergic asthma were higher than that of intrinsic asthma and normal controls. The serum levels of IL-12 and IFN-$\gamma$ in patients with allergic asthma and intrinsic asthma were significantly lower than those in normal controls(p<0.05). The serum levels of total immunoglobulin E (IgE) and peripheral blood eosinophile counts in patients with allergic asthma were significantly higher than those in normal controls. Peripheral blood esinophil counts had a significant correlation with the serum levels of total IgE, IL-5 and IL-10 in patients with allergic asthma (p<0.05). Conclusion: These results have showed that Th1 lymphocyte functions were lowered and Th2 lymphocyte functions were elevated in patients with allergic asthma than those in normal controls. Suppression of Th1 lymphocyte functions by activation of Th2 lymphocyte might be one of the important aspects of pathogenesis in allergic bronchial asthma.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.478-486
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• 2000

Background : In acute lung injury, alveolar macrophages play a pivotal role in the inflammatory process during the initiation phase and in the reconstruction and fibrosis process during the later phase. Recently, it has been proven that alveolar macrophages are constituted by morphologically, biochemically and immunologically heterogenous cell subpopulations. The possibility of alterations to these characteristics of the alveolar macrophage population during lung disease has been raised. To investigate such a possibility a hyperoxic rat lung model was made to check the distributional and morphological changes of rat alveolar macrophage subpopulation in acute hyperoxic lung injury. Method : Alveolar macrophage were lavaged from normal and hyperoxic lung injury rats and separated by discontinuous gradients of percoll. After cell counts of each density fraction were accessed, the morphomeric analysis of alveolar macrophages was performed on cytocentrifuged preparations by transmission electron micrograph. Result : 1. The total alveolar macrophage cell count significantly increased up to 24 hours after hyperoxic challenge (normal control group $171.6{\pm}24.1{\times}10^5$, 12 hour group $194.8{\pm}17.9{\times}10^5$, 24 hour group $207.6{\pm}27.1{\times}10^5$, p<0.05). oHoHH However the 48 hour group ($200.0{\pm}77.8{\times}10^5$) did not show a significant difference. 2. Alveolar septal thickness significantly increased up to 24 hours after hyperoxic challenge(normal control group $0.7{\pm}0.2{\mu}m$, 12 hour group $1.5{\pm}0.4{\mu}m$, 24 hour group $2.3{\pm}0.4{\mu}m$, p<0.05). However the 48 hour group did not show further change ($2.5{\pm}0.4{\mu}m$). Number of interstitial macrophage markedly increased at 24 hour group. 3. Hypodense fraction(fraction 1 and fraction 2) of alveolar macrophage showed a significant increase following hyperoxic challenge ($\beta=0.379$.$\beta=0.694$. p<0.05) ; however, fraction 3 was rather decreased following the hyperoxic challenge($\beta=0.815$. p<0.05), and fraction 4 showed an irregular pattern. 4. Electron microscopic observation of alveolar macrophage from each fraction revealed considerable morphologic heterogeneity. Cells of the most dense subfraction(fraction 4) were small, round, and typically highly ruffled with small membrane pseudopods. Cells of the least dense fraction (fraction 1) were large and showed irregular eccentric nucleus and high number of heterogenous inclusions. Conclusion : In conclusion, these results suggest that specific hypodense alveolar macrophage subpopulation may play a an important role in an acute hyperoxic lung injury model But further study, including biochemical and immunological function of these subpopulations, is needed.

• Tuberculosis and Respiratory Diseases
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• v.58 no.6
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• pp.590-599
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• 2005

Object : Cigarette smoking is a major cause of mucus hypersecretion, which is a pathophysiological feature of many inflammatory airway diseases. Mucins, which are an important part of the airway mucus, are synthesized from the Muc gene in airway epithelial cells. However, the signaling pathways for cigarette smoke-induced mucin synthesis are unknown. The aim of this study was to determine the signal pathway for smoking induced Muc5ac gene expression. Methods : A549 cells were cultured and transiently transfected with the Muc5ac promoter fragment. These cells were stimulated with 5% cigarette smoke extract (CSE) alone or with CSE after a pretreatment with various signal transduction pathway inhibitors (AG1478, PD98059 and SB203580). The Muc5ac promoter activity was examined using the luciferase reporter system, and the level of phosphorylated EGFR, ERK1/2, p38 MAPK and JNK were all examined using Western blot analysis. Muc5ac mRNA expression was also examined using reverse transcriptase polymerase chain reactions (RT-PCR). Results : 1. The peak level of luciferase activity of the Muc5ac promoter was observed at 5% concentration and after 3 hours of incubation with the CSE. The level of EGFR phosphorylation and the luciferase activity of the transfected cells caused by the CSE were significantly suppressed by AG1478 or PD98059 (P<0.01). 2. CSE phosphorylated ERK1/2 or p38 MAPK but not JNK. The Muc5ac mRNA expression level was increased by the CSE but that was suppressed by PD98059 or AG1478. 3. The CSE-induced phosphorylation of ERK1/2 was blocked by PD98059 and that of p38 MAPK was blocked by either PD98059 or SB203580. Either PD98059 or SB203580 suppressed the luciferase activity of the transfected cells (P<0.0001). Conclusion : The Muc5ac mRNA expression level was increased by the CSE. The increased CSE-induced transcriptional activity was mediated via EGF receptor activation, which led to ERK1/2 and p38 MAPK phosphorylation.