• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.109-116
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• 2016

Purpose: Recent observational studies have found that vitamin D deficiency is associated with respiratory tract infections. However, randomized controlled trials (RCTs) regarding the efficacy of vitamin D in childhood respiratory tract infection (RTI) have yield inconsistent results. We performed a systematic review and meta-analysis to evaluate the association between vitamin D supplementation and the risk of RTI. Methods: A comprehensive search was conducted using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trial. Randomized controlled trials of vitamin D supplementation for prevention of RTI in children were included for the analysis. Cochrane Collaboration's tool for assessing the risk of bias was used to assess the quality of the studies. Pooled risk ratios with 95% confidence intervals (CIs) were meta-analyzed using Review Manager 5.3. Results: A total of seven RCTs were included in the meta-analysis. According to a random-effects model, the risk ratio for vitamin D supplementation was 0.82 (95% CI: 0.69-0.98) and $I^2=62%$ for heterogeneity. On subgroup analysis, heterogeneity decreased in the subgroup with follow-up less than 1 year, participants ${\geq}5years$ of age, patients subgroup, and subgroup with dosing daily. Funnel plot showed that there might be publication bias in the field. Conclusions: The present meta-analysis supports a beneficial effect of vitamin D supplementation for the prevention of RTI in children. However, the result should be interpreted with caution due to limitations including a small number of available RCTs, heterogeneity among the studies, and potential publication bias.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.194-200
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• 2015

Purpose: Urinary tract infection (UTI) is a common bacterial infection in children and Escherichia coli is a predominant pathogen. The purpose of this study is to evaluate phylogenetic groups and virulence factors of E. coli causing UTI in children in Korea. Methods: From October 2010 to April 2013, urinary E. coli strains were isolated from the 33 pediatric patients of UTI. Multiplex polymerase chain reactions were performed to evaluate the phylogenetic groups and 5 virulence factor genes (fimH, sfa, papA, hylA, and cnf1) of E. coli. Distribution of molecular characteristics of E. coli was analyzed by clinical diagnosis and accompanying vesicoureteral reflux (VUR). Results: Most (84.8%) uropathogenic E. coli were belonged to phylogenetics group B2 and the others (15.2%) were belonged to group D. The virulence factors were distributed as: fimH (100%), sfa (100%), hylA (63.6%), cnfI (63.6%), and papA (36.4%). According to clinical diagnosis, phylogenetic distribution of E. coli strain was 92.3% of B2 and 7.7% of D in acute pyelonephritis and 57.1% of B2 and 42.9% of D in cystitis. Distribution of virulence factors was similar in both groups. In patients with acute pyelonephritis, phylogenetic distribution was similar in VUR and non-VUR group, but proportion of papA genes were lower in VUR group than that of non-VUR group (43.8% vs. 20.0%, P=0.399). Conclusions: This study provides current epidemiologic molecular data of E. coli causing pediatric UTI in Korea and will be a fundamental for understanding the pathogenesis of pediatric UTI.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.23-28
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• 2015

Purpose: The aim of this study was to investigate the clinical manifestations and laboratory characteristics of eosinophilic meningitis in Severance Children's Hospital. Methods: We examined 6,335 children under the age of 18 years old who had visited the tertiary hospital in Seoul, Korea, and had received cerebrospinal study results between January 2007 and July 2012. The medical records of the patients identified as eosinophilic meningitis were retrospectively reviewed. Results: Eosinophilic meningitis was diagnosed in 39 patients (0.6%). The mean age was 6 years (range 0-18 years) and the sex ratio was 1.3:1 (22 males and 17 females). The underlying diseases and past history were neurologic disease (n=36, 92%). Eosinophilic meningitis was diagnosed in thirty-five patients who had undergone postoperation neurosurgery (90%). The most common symptoms were fever (50%), headache (20%), vomiting (15%), seizure (10%), and dizziness (5%). The average duration for recovery was five days, and intravenous antibiotics or steroids were used. Conclusions: Manifestations of eosinophilic meningitis are similar to other types of meningitis. The most common cause of eosinophilic meningitis in children was neurosurgery. Eosinophilic meningitis should be considered for patients showing fever and headache after neurosurgery. Through careful investigation, use of improper antibiotics could be avoided.

• Pediatric Infection and Vaccine
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• v.26 no.3
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• pp.179-187
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• 2019

Purpose: Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is a leading cause of periodic fever in children. This study describes the clinical characteristics of PFAPA syndrome in patients from a single center. Methods: Thirteen children diagnosed with PFAPA syndrome at Seoul National University Children's Hospital were included in this study. Retrospective medical chart reviews were performed. Results: Among the 13 patients, 8 (61.5%) were male. The median follow-up duration was 3.3 years (range, 10 months-8.3 years). The median age of periodic fever onset was 3 years (range, 1-6 years). All patients had at least 5 episodes of periodic fever and pharyngitis, managed with oral antibiotics, before diagnosis. The median occurrence of fever was every 3.9 weeks and lasted for 4.2 days. All patients had pharyngitis and 12 (92.3%) had cervical lymphadenitis. Blood tests were performed for 12 patients, and no patients had neutropenia. Both the C-reactive protein and erythrocyte sedimentation rate were elevated at medians of 4.5 mg/dL (range, 0.4-13.2 mg/dL) and 29 mm/hr (range, 16-49 mm/hr), respectively. Throat swab cultures and rapid streptococcal antigen tests were negative. Nine (69.2%) patients received oral prednisolone at a median dose of 0.8 mg/kg, and in 6 (66.7%) patients, fever resolved within a few hours. Three (23.1%) patients received tonsillectomy and adenoidectomy. Conclusions: PFAPA syndrome should be considered when a child presents with periodic fever along with aphthous stomatitis, pharyngitis, or cervical lymphadenitis. Glucocorticoid administration is effective for fever resolution and can reduce unnecessary use of antibiotics.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.25-30
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• 2016

Purpose: We undertook this study to investigate discrepancies in C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values, and variations following intravenous immunoglobulin (IVIG) therapy in Kawasaki disease (KD). Methods: A total of 123 KD patients were retrospectively enrolled. Patients were treated with IVIG 2 g/kg at 2 to 9 days after disease onset. We obtained white blood cell (WBC) count, percentage of neutrophils (% neutrophils), CRP, ESR, and N-terminal pro-brain natriuretic peptide (NT-proBNP) values before and 48 to 72 hours after IVIG treatment. Discrepancy was defined as $CRP{\geq}10mg/dL$ and ESR <50 mm/hr (Group 1), or CRP <10 mg/dL and $ESR{\geq}50mm/hr$ (Group 2). Results: Thirty-six of 123 subjects (29.2%) had a discrepancy: 25 (20.3%) in Group 1 and 11 (8.9%) in Group 2. In Group 1, 15 patients (60%) had fever for <5 days (early presenter) and 10 (40%) had fever for ${\geq}5days$ (late presenter). There were six early presenters (55%) and five late presenters (45%) in Group 2. Late presenters had higher ESR than early presenters ($34.3{\pm}21.0mm/hr$ vs. $26.3{\pm}19.3mm/hr$, P=0.029). After IVIG treatment, elevated WBC count, % neutrophils, CRP, and NT-proBNP levels normalized. In contrast, ESR increased from $37.4{\pm}21.9mm/hr$ to $48.0{\pm}22.7mm/hr$ (n=36, P=0.051). Conclusions: A discrepancy may be related to the duration of fever. Due to discrepancies in CRP and ESR values in acute KD, both should be measured to assess the degree of inflammatory activity before IVIG treatment. After IVIG treatment, the ESR should not be used as a marker of response to therapy in KD.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.324-333
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• 2013

Recently, rudder erosion due to cavitation has been frequently reported on a semi-spade rudder of a high-speed large ship. This problem raises economic and safety issues when operating ships. The semi-spade rudders have a gap between the horn/pintle and the movable wing part. Due to this gap, a discontinuous surface, cavitation phenomenon arises and results in unresolved problems such as rudder erosion. In this study, we made a rudder model for 2-D experiments using the NACA0020 and also manufactured gap flow blocking devices to insert to the gap of the model. In order to study the gap flow characteristics at various rudder deflection angles($5^{\circ}$, $10^{\circ}$, $35^{\circ}$) and the effect of the gap flow blocking devices, we carried out the velocity measurements using PIV(Particle Image Velocimetry) techniques and cavitation observation using high speed camera in Seoul National University cavitation tunnel. To observe the gap cavitation on a semi-spade rudder, we slowly lowered the inside pressure of the cavitation tunnel until cavitation occurred near the gap and then captured it using high-speed camera with the frame rate of 4300 fps(frame per second). During this procedure, cavitation numbers and the generated location were recorded, and these experimental data were compared with CFD results calculated by commercial code, Fluent. When we use gap flow blocking device to block the gap, it showed a different flow character compared with previous observation without the device. With the device blocking the gap, the flow velocity increases on the suction side, while it decreases on the pressure side. Therefore, we can conclude that the gap flow blocking device results in a high lift-force effect. And we can also observe that the cavitation inception is delayed.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.95-101
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• 2017

Purpose: Acute bacterial gastroenteritis (ABG) can cause more severe symptoms than acute viral gastroenteritis in children. This study was aimed at determining the etiologic trends and to examine the clinical characteristics of ABG in children. Methods: We sent stool samples from the children with acute gastroenteritis who were treated at a secondary hospital located in Seoul, Korea between January 2011 and December 2014 to Seoul Metropolitan Government Research Institute of Public Health and Environment to find the causative organisms. Clinical characteristics of patient were analyzed through a medical records review. Results: Out of 664 stool samples, 183 (27.6%) yielded bacterial pathogens. Staphylococcus aureus was the most common bacterial pathogen, found in 72 cases (39.3%), even though it was only tested for since 2012. The monthly isolation rate was the highest (24.6%) in August. The isolation rate of Campylobacter spp. by patient's age group was high (16.7%) in the 12- to 18-year-age group (P=0.04). In patients with bloody stool, Campylobacter spp. was the most commonly isolated (31.0%, P=0.04). When comparing C-reactive protein, the Salmonella spp.- or Campylobacter spp.-isolated group showed higher values than the S. aureus- or pathogenic Escherichia coli-isolated group ($5.7{\pm}0.6mg/dL$ vs. $2.1{\pm}0.3mg/dL$, P<0.01). Conclusions: S. aureus, Salmonella spp., pathogenic E. coli, and Campylobacter spp. were important pathogens of ABG among children. Considering the differences in pathogens found according to age, a clinical symptom and inflammation index might be helpful in assuming the causative organism.

• Clinical and Experimental Pediatrics
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• v.51 no.7
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• pp.729-735
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• 2008

Purpose : Chlamydia trachomatis is one of the most common sexually transmitted diseases and is also a cause of pneumonia in infants. Respiratory infections by respiratory viruses are also common for infants. The objectives of this study were to identify the clinical manifestations and to determine the prevalence of C. trachomatis respiratory infections and coinfections by respiratory viruses in infants younger than 6 months of age. Methods : For this study, we enrolled 6 months or younger infants who were admitted to the Dankook University Hospital between January 2002 and July 2007, with respiratory symptoms. Nasopharyngeal aspirates or throat swabs were collected within s d of hospitalization and C. trachomatis was detected using polymerase chain reaction (PCR). Patients who tested positive underwent multiplex PCR for respiratory viruses. Results : A total of 690 patients underwent chlamydial PCR testing and 36 (5.2%) had positive results. Of the 36, 28 (78%) were male; 30 were vaginally delivered. From the 36 patients positive for C. trachomatis, 26 underwent multiplex respiratory viral PCR; 12 were coinfected with viruses. Respiratory syncytial virus (RSV) was the most frequent pathogen that was detected in 6 patients. Increased C-reactive protein and fever were significant in patients coinfected with respiratory viruses. Conclusion : C. trachomatis can infected in infants delivered by cesarean section as well as in 6 months old or younger infants. Infant with C. trachomatis respiratory infections can also be coinfected with respiratory infection also coinfected with respiratory viruses. Further studies are needed to better understand the prevalence rates of the this infection and its coinfection rate with respiratory viruses.