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1.  Increased risk of refractory Mycoplasma pneumoniae pneumonia in children with atopic sensitization and asthma 
Korean Journal of Pediatrics  2014;57(6):271-277.
A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP.
We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over 38.3℃ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases.
There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender.
Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.
PMCID: PMC4115068  PMID: 25076972
Asthma; Atopy; Child; Pneumonia; Mycoplasma
2.  Prevalence of respiratory viral infection in children hospitalized for acute lower respiratory tract diseases, and association of rhinovirus and influenza virus with asthma exacerbations 
Korean Journal of Pediatrics  2014;57(1):29-34.
In this study, we aimed to investigate the prevalence of year-round respiratory viral infection in children with lower respiratory tract infection (LRTI) and the relationship between respiratory viral infection and allergen sensitization in exacerbating asthma.
We investigated the sources for acute LRTIs in children admitted to our hospital from May 2010 to April 2011. The 6 most common respiratory viruses were isolated from nasopharyngeal aspirate using multiplex reverse transcription-polymerase chain reaction in 309 children; respiratory syncytial virus (RSV), adenovirus (AV), parainfluenza virus (PIV), influenza virus (IFV), human metapneumovirus (hMPV), rhinovirus (RV). Atopic sensitization was defined if more than 1 serum specific Immunoglobulin E level measured using UniCAP (Pharmacia) was over 0.35 IU/mL.
RSV was the most common pathogen of bronchiolitis in hospitalized children through the year. RV or IFV infection was more prevalent in asthma exacerbations compared to other LRTIs. AV and hMPV were more likely to cause pneumonia. RV and IFV were associated with asthma exacerbations in children with atopic sensitization, but not in nonatopic children.
RV and IFV are associated with hospitalization for asthma exacerbation in children with atopic sensitization.
PMCID: PMC3935110  PMID: 24578714
Asthma; Allergens; Child; Orthomyxoviridae; Rhinovirus
3.  Effects of Diet-Induced Mild Obesity on Airway Hyperreactivity and Lung Inflammation in Mice 
Yonsei Medical Journal  2013;54(6):1430-1437.
Obesity has been suggested to be linked to asthma. However, it is not yet known whether obesity directly leads to airway hyperreactivity (AHR) or obesity-induced airway inflammation associated with asthma. We investigated obesity-related changes in adipokines, AHR, and lung inflammation in a murine model of asthma and obesity.
Materials and Methods
We developed mouse models of chronic asthma via ovalbumin (OVA)-challenge and of obesity by feeding a high-fat diet, and then performed the methacholine bronchial provocation test, and real-time PCR for leptin, leptin receptor, adiponectin, adiponectin receptor (adipor1 and 2), vascular endothelial growth factor (VEGF), transforming growth factor (TGF) β, and tumor necrosis factor (TNF) α in lung tissue. We also measured cell counts in bronchoalveolar lavage fluid.
Both obese and lean mice chronically exposed to OVA developed eosinophilic lung inflammation and AHR to methacholine. However, obese mice without OVA challenge did not develop AHR or eosinophilic inflammation in lung tissue. In obese mice, lung mRNA expressions of leptin, leptin receptor, VEGF, TGF, and TNF were enhanced, and adipor1 and 2 expressions were decreased compared to mice in the control group. On the other hand, there were no differences between obese mice with or without OVA challenge.
Diet-induced mild obesity may not augment AHR or eosinophilic lung inflammation in asthma.
PMCID: PMC3809850  PMID: 24142648
Adipokine; asthma; high fat; vascular endothelial growth factor; transforming growth factor beta; tumor necrosis factor alpha; obesity; airway hyperresponsiveness
4.  Klebsiella pneumoniae liver abscess in an immunocompetent child 
Korean Journal of Pediatrics  2013;56(9):407-410.
Klebsiella pneumoniae has emerged as a leading pathogen that causes pyogenic liver abscesses (PLAs) in Korea. K. pneumoniae liver abscess (KLA) is potentially life threatening, and the diagnosis is difficult. In developed countries, PLA is rarely observed in children and is frequently associated with disorders of granulocyte function and previous abdominal infection. We observed a case of KLA in a healthy 12-year-old boy. To our knowledge, this is the first reported case of KLA in an immunocompetent child without an underlying disease in Korea. The patient was treated with percutaneous catheter drainage and antibiotics. The catheter was placed in the intrahepatic abscess for 3 weeks and parenteral antibiotics (ceftriaxone and amikacin) were administered for 4 weeks, followed by oral antibiotics (cefixime) for 2 weeks. We reported this case to raise awareness of KLA in immunocompetent children among physicians, and to review the diagnosis, risk factors, potential complications, and appropriate treatment of KLA.
PMCID: PMC3819678  PMID: 24223603
Klebsiella pneumoniae; Liver Abscess; Immunity; Child
5.  Increased Prevalence of H1N1-Induced Severe Lower Respiratory Tract Diseases in Children With Atopic Sensitization 
Viral infection is the most common aggravating factor for childhood asthma. Asthma may be a risk factor for severe respiratory symptoms in children with lower respiratory tract infections of viral etiology. Influenza A infection enhances Th2-polarization to house dust mites during the acute phase and leads to lung dysfunction in a mouse model. However, there are no data on the relationship between atopic sensitization and H1N1 (Influenza A) infection in humans. To investigate whether atopic sensitization is associated with the severity of H1N1 pneumonia, we compared clinical features and the atopic sensitization rate between children with and without H1N1 infection.
Using reverse transcription-polymerase chain reactions, we investigated H1N1 virus infection in 214 children who were hospitalized with high fever and respiratory symptoms from September 2009 to February 2010. We also performed immunoassays for total and specific IgEs to six common aeroallergens. Atopy was defined as positivity for more than one specific IgE. The clinical severity of pneumonia was evaluated based on intensive care unit admission, oxygen therapy, steroid therapy, and atelectasis.
There were 70 H1N1-positive children, 42.9% of whom had pneumonia. Children with H1N1 infection were older and had a higher prevalence of atopic sensitization and pneumonia compared with H1N1-negative children. The rate of atelectasis was higher in children with H1N1 pneumonia than in children with non-H1N1 pneumonia. Among children with H1N1 viral infection, those with atopic sensitization had a higher prevalence of intensive care unit admission and oxygen therapy, and a longer duration of hospitalization than non-atopic children. There were no differences between atopic and non-atopic children without H1N1 viral infection.
The prevalence of H1N1-induced severe lower respiratory tract diseases is higher in children with atopic sensitization.
PMCID: PMC3423601  PMID: 22950033
H1N1 virus; atopy; pneumonia; severity; children
6.  Successful and safe treatment of hemangioma with oral propranolol in a single institution 
Korean Journal of Pediatrics  2012;55(5):164-170.
Dramatic improvement of hemangioma to propranolol has been recently reported; however, details on dose and duration of treatment, potential risks, and monitoring have not been determined. The objective of this study is to describe and analyze the use of propranolol as a first-line treatment or as a single therapy in management of complicated hemangioma.
A retrospective chart review of eight patients diagnosed with hemangioma and treated with propranolol in Kangbuk Samsung Hospital from February 2010 to April 2011 was performed.
Eight patients with hemangioma with functional impairment, cosmetic disfigurement, or rapid growth were treated with propranolol. Five patients had solitary facial hemangioma. The mean age of symptoms at onset was 5 weeks. The median age for starting propranolol treatment was 5.5 months. Propranolol at 2 mg/kg/day was finally administered in divided doses with a gradual increase. Significant regression was observed in seven patients, and shrinkage in size, softening in consistency, and decrease in redness were evident within 4 weeks. Among them, six patients were still taking propranolol, and one patient had stopped after 12 months. Other one patient did not show significant improvement with satisfactory result after 3 months of propranolol use. Treatment with propranolol was well tolerated and had few side effects. No rebound growth was observed in any of the patients.
We observed that use of propranolol was very effective in treatment of hemangioma without obvious adverse effects or relapse.
PMCID: PMC3362730  PMID: 22670151
Hemangioma; Propranolol; Treatment
7.  The Effect of Interleukin-4 and Amphiregulin on the Proliferation of Human Airway Smooth Muscle Cells and Cytokine Release 
Journal of Korean Medical Science  2008;23(5):857-863.
Airway smooth muscle (ASM) hyperplasia and angiogenesis are important features associated with airway remodeling. We investigated the effect of IL-4 and amphiregulin, an epidermal growth factor family member, on the proliferation of human ASM cells and on the release of vascular endothelial growth factor (VEGF) and monocyte chemotactic protein (MCP)-1 from human ASM cells. Human ASM cells were growth-arrested for 48 hr and incubated with platelet-derived growth factor (PDGF)-BB, interleukin (IL)-4, amphiregulin, and VEGF to evaluate cell proliferation. The cells were treated with PDGF, IL-4 and amphiregulin to evaluate the release of VEGF, MCP-1. IL-4 suppressed unstimulated and PDGF-stimulated ASM cell proliferation. Amphiregulin stimulated ASM cell proliferation in a dose-dependent manner. VEGF did not have any influence on ASM cell proliferation. IL-4 stimulated VEGF secretion by the ASM cells in a dose-dependent manner and showed added stimulatory effects when co-incubated with PDGF. Amphiregulin did not promote VEGF secretion. IL-4 and amphiregulin showed no stimulatory effects on MCP-1 secretion. The results of this study showed that IL-4 had bifunctional effects on airway remodeling, one was the suppression of the proliferation of the ASM cells and the other was the promotion of VEGF release by the ASM cells, and amphiregulin can promote human ASM cell proliferation.
PMCID: PMC2580012  PMID: 18955794
Interleukin-4; Remodeling; Humans, Bronchi; Myocytes, Smooth Muscle; Cell Proliferation; Vascular Endothelial Growth Factor; Amphiregulin
8.  Vagus Nerve Stimulation in Intractable Childhood Epilepsy: a Korean Multicenter Experience 
Journal of Korean Medical Science  2007;22(3):442-445.
We evaluated the long-term outcome of vagus nerve stimulation (VNS) in 28 children with refractory epilepsy. Of these 28 children, 15 (53.6%) showed a >50% reduction in seizure frequency and 9 (32.1%) had a >75% reduction. When we compared seizure reduction rates according to seizure types (generalized vs. partial) and etiologies (symptomatic vs. cryptogenic), we found no significant differences. In addition, there was no correlation between the length of the stimulation period and treatment effect. The seizure reduction rate, however, tended to be inversely related to the seizure duration before VNS implantation and age at the time of VNS therapy. VNS also improved quality of life in this group of patients, including improved memory in 9 (32.1%), improved mood in 12 (42.9%), improved behavior in 11 (39.3%), improved altertness in 12 (42.9%), improved achievement in 6 (21.4%), and improved verbal skills in 8 (28.6%). Adverse events included hoarseness in 7 patients, dyspnea at sleep in 2 patients, and wound infection in 1 patient, but all were transient and successfully managed by careful follow-up and adjustment of parameters. These results indicate that VNS is a safe and effective alternative therapy for pediatric refractory epilepsy, without significant adverse events.
PMCID: PMC2693635  PMID: 17596651
Vagus Nerve Stimulation; Epilepsy; Child
9.  Serum Vascular Endothelial Growth Factor in Pediatric Patients with Community-Acquired Pneumonia and Pleural Effusion 
Journal of Korean Medical Science  2006;21(4):608-613.
This study investigated the serum vascular endothelial growth factor (VEGF) levels in children with community-acquired pneumonia. Serum VEGF levels were measured in patients with pneumonia (n=29) and in control subjects (n=27) by a sandwich enzyme-linked immunosorbent assay. The pneumonia group was classified into bronchopneumonia with pleural effusion (n=1), bronchopneumonia without pleural effusion (n=15), lobar pneumonia with pleural effusion (n=4), and lobar pneumonia without pleural effusion (n=9) groups based on the findings of chest radiographs. We also measured serum IL-6 levels and the other acute inflammatory parameters. Serum levels of VEGF in children with pneumonia were significantly higher than those in control subjects (p<0.01). Children with lobar pneumonia with or without effusion showed significantly higher levels of serum VEGF than children with bronchopneumonia. For lobar pneumonia, children with pleural effusion showed higher levels of VEGF than those without pleural effusion. Children with a positive urinary S. pneumonia antigen test also showed higher levels of VEGF than those with a negative result. Serum IL-6 levels did not show significant differences between children with pneumonia and control subjects. Serum levels of VEGF showed a positive correlation with the erythrocyte sedimentation rate in the children with pneumonia. In conclusion, VEGF may be one of the key mediators that lead to lobar pneumonia and parapneumonic effusion.
PMCID: PMC2729879  PMID: 16891801
Vascular Endothelial Growth Factor A; Interleukin-6; Pleural Effusion; Community-Acquired Infections; Pneumonia
10.  Postoperative Electroencephalogram for Follow up of Pediatric Moyamoya Disease 
Journal of Korean Medical Science  2006;21(3):495-499.
It is well known that the electroencephalographic finding in patients with moyamoya disease demonstrates the characteristic "re-build up" phenomenon a few minutes after hyperventilation. To evaluate the usefulness of an electroencephalogram (EEG) in the postoperative management of children with moyamoya disease, we studied the presence or absence of improvement in the clinical, single photon emission computed tomography (SPECT) and EEG findings, before and after surgery. Twenty-two patients, who underwent indirect revascularization surgery for moyamoya disease, were included in our study. Clinical improvement was assessed as the disappearance or decrease of a transient ischemic attack or headache. The findings on the EEG and SPECT were considered improved when the re-build up phenomenon was absent and when there was improvement in the cerebrovascular reserve as a result of the acetazolamide challenge test. The statistical correlation analysis for both clinical and EEG improvement were consistent (kappa value=0.409, p<0.05). However, the result from the clinical and SPECT improvement as well as that from EEG and SPECT improvement were not statistically significant. Our results suggest that EEG can be used as a noninvasive and simple follow-up test for moyamoya disease after indirect revascularization surgery if the hyperventilation procedure is effectively performed during EEG recording.
PMCID: PMC2729958  PMID: 16778396
Moyamoya Disease; Electroencephalography; Follow-up Studies
11.  A protein domain interaction interface database: InterPare 
BMC Bioinformatics  2005;6:207.
Most proteins function by interacting with other molecules. Their interaction interfaces are highly conserved throughout evolution to avoid undesirable interactions that lead to fatal disorders in cells. Rational drug discovery includes computational methods to identify the interaction sites of lead compounds to the target molecules. Identifying and classifying protein interaction interfaces on a large scale can help researchers discover drug targets more efficiently.
We introduce a large-scale protein domain interaction interface database called InterPare . It contains both inter-chain (between chains) interfaces and intra-chain (within chain) interfaces. InterPare uses three methods to detect interfaces: 1) the geometric distance method for checking the distance between atoms that belong to different domains, 2) Accessible Surface Area (ASA), a method for detecting the buried region of a protein that is detached from a solvent when forming multimers or complexes, and 3) the Voronoi diagram, a computational geometry method that uses a mathematical definition of interface regions. InterPare includes visualization tools to display protein interior, surface, and interaction interfaces. It also provides statistics such as the amino acid propensities of queried protein according to its interior, surface, and interface region. The atom coordinates that belong to interface, surface, and interior regions can be downloaded from the website.
InterPare is an open and public database server for protein interaction interface information. It contains the large-scale interface data for proteins whose 3D-structures are known. As of November 2004, there were 10,583 (Geometric distance), 10,431 (ASA), and 11,010 (Voronoi diagram) entries in the Protein Data Bank (PDB) containing interfaces, according to the above three methods. In the case of the geometric distance method, there are 31,620 inter-chain domain-domain interaction interfaces and 12,758 intra-chain domain-domain interfaces.
PMCID: PMC1236910  PMID: 16122378
12.  Main pulmonary artery stenosis caused by fibrocalcified mass in a young infant. 
Journal of Korean Medical Science  2002;17(4):560-563.
We present a rare case of main pulmonary artery stenosis secondary to protruding fibrous material in the main pulmonary artery associated with patent ductus arteriosus. A 1-month-old baby boy manifested cardiac murmur. Echocardiogram showed circumferential high echogenic mass inside the main pulmonary artery with pressure gradient of 49 mmHg and patent ductus arteriosus. The mass did not regress during 3 months' follow-up period. Angiographic images showed that the circular filling defect was located at the main pulmonary artery distal to pulmonary valve, and pulmonary valve and both pulmonary arteries were normal. After surgical removal of the circumferential material and ductus ligation, the pressure gradient became negligible. The material was consisted of scarcely cellular fibrous tissue, abundant coagulum of fibrinous material and dense calcification.
PMCID: PMC3054921  PMID: 12172057

Results 1-12 (12)