Woo Jin Chung

Keimyung University, Sŏul, Seoul, South Korea

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Publications (83)195.83 Total impact

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    ABSTRACT: Given the characteristic procedures involved in the endoscopy unit, the spread of pathogens is much more frequent in this unit than in other environments. However, there is a lack of data elucidating the existence of pathogens in the endoscopy unit. The aim of this study was to detect the presence of possible pathogens in the endoscopy unit.
    Intestinal research. 10/2014; 12(4):306-12.
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    ABSTRACT: Only a few studies have evaluated the population-adjusted prevalence of gallbladder polyps (GBP). This study aimed to evaluate the changes in GBP prevalence and risk factors at a single health screening center in Korea from 2002 to 2012. Of 48,591 adults who underwent health screening between 2002 and 2012, 14,250 age- and gender-matched subjects were randomly selected to evaluate prevalence. Risk factors were analyzed between the GBP-positive and GBP-negative groups during 2002-2004 (Period A) and 2010-2012 (Period B). The annual prevalence of GBP over the 11-yr period was 5.4%. Annual prevalence increased from 3.8% in Period A to 7.1% in Period B. Male gender and obesity were independent risk factors for GBP in both periods. Hepatitis B virus surface antigen (HBsAg) positivity was a risk factor for GBP in Period A but not in Period B. The risk factors for GBP changed from HBsAg positivity to lipid profile abnormalities. Other variables including age, hypertension, diabetes, impaired fasting glucose, chronic hepatitis C virus infection, and liver function tests did not correlate with GBP. In conclusion, GBP prevalence is increasing and risk factors for GBP have changed in Korea. More attention should be paid to this issue in the future.
    Journal of Korean Medical Science 09/2014; 29(9):1247-52. · 1.25 Impact Factor
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    ABSTRACT: The aim of this study was to compare the efficacy of hepatic arterial infusion chemotherapy (HAIC) and sorafenib in advanced hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT).
    Journal of gastroenterology. 07/2014;
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    ABSTRACT: To compare outcomes using the novel portable endoscopy with that of nasogastric (NG) aspiration in patients with gastrointestinal bleeding.
    World journal of gastroenterology : WJG. 07/2014; 20(25):8221-8.
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    ABSTRACT: To compare the esophagogastric junction (EGJ) areas observed in sedated and non-sedated patients during esophagogastroduodenoscopy (EGD). Data were collected prospectively from consecutive patients who underwent EGD for various reasons. The patients were divided into three groups according to the sedation used: propofol, midazolam, and control (no sedation). The EGJ was observed during both insertion and withdrawal of the endoscope. The extent of the EGJ territory observed was classified as excellent, good, fair, or poor. In addition, the time the EGJ was observed was estimated. The study included 103 patients (50 males; mean age 58.44 ± 10.3 years). An excellent observation was achieved less often in the propofol and midazolam groups than in the controls (27.3%, 28.6% and 91.4%, respectively, P < 0.001). There was a significant difference in the time at which EGJ was observed among the groups (propofol 20.7 ± 11.7 s vs midazolam 16.3 ± 7.3 s vs control 11.6 ± 5.8 s, P < 0.001). Multivariate analysis showed that sedation use was the only independent risk factor for impaired EGJ evaluation (propofol, OR = 24.4, P < 0.001; midazolam, OR = 25.3, P < 0.001). Hiccoughing was more frequent in the midazolam group (propofol 9% vs midazolam 25.7% vs control 0%, P = 0.002), while hypoxia (SaO2 < 90%) tended to occur more often in the propofol group (propofol 6.1% vs midazolam 0% vs control 0%, P = 0.101). Sedation during EGD has a negative effect on evaluation of the EGJ.
    World Journal of Gastroenterology 05/2014; 20(18):5527-32. · 2.55 Impact Factor
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    ABSTRACT: A novel synthetic and processing strategy for converting elemental sulfur into polymeric and nanocomposite materials is reported. We describe a facile one-pot reaction using elemental sulfur and oleylamine as comonomers to prepare high sulfur content copolymers and lead sulfide nanoparticle (PbS NP) nanocomposites. This process enables the preparation of solution processable copolymers and nanocomposites, where the loading and dispersion of PbS NP inclusions could be precisely controlled. We demonstrate the dual roles of oleylamine with sulfur for both the copolymerization of sulfur copolymers as well as the in situ synthesis of PbS NPs in a one-pot fashion.
    Polym. Chem. 05/2014; 5(11).
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    ABSTRACT: Polymers for IR imaging: The preparation of high refractive index polymers (n = 1.75 to 1.86) via the inverse vulcanization of elemental sulfur is reported. High quality imaging in the near (1.5 μm) and mid-IR (3-5 μm) regions using high refractive index polymeric lenses from these sulfur materials was demonstrated.
    Advanced Materials 03/2014; · 14.83 Impact Factor
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    ABSTRACT: Hepatocellular carcinoma (HCC) is the fourth most common form of cancer in the Korean population, caused primarily by infection with either the Hepatitis B or C virus. Progression of this disease is frequently associated with mutations in either phosphoinositide-3-kinase, catalytic, alpha (PIK3CA) or hepatitis B virus X (HBx) gene. Previous studies have examined the frequency of PIK3CA mutations in HCC, although the clinical significance of these mutations has not been studied in a Korean population. In addition, HBx appears to play a key role in modulating a wide range of cellular functions, leading to HCC. In this study, we examined microdissected tumor samples from 50 HCC patients who underwent hepatectomy at Keimyung University Dongsan Medical Center. These patients were screened for mutations in PIK3CA and HBx to identify the clinical outcomes associated with these mutations. Exons 9 and 20 of PIK3CA and the entirety of HBx were screened for mutations by polymerase chain reaction and direct DNA sequencing. PIK3CA mutations were detected in 7 of 50 patients (14%). Among the 42 patients who were seropositive for hepatitis B, 17 (40.5%) had HBx mutations and 4 (9.52%) had mutations in PIK3CA. PIK3CA mutations were strongly correlated with tumor size. Patients harboring HBx mutations exhibited a longer time to recurrence; this difference was statistically significant not only in comparison with the PIK3CA mutation but also compared with those without any mutations. This result suggests a role for PIK3CA and HBx mutations as prognostic markers in HCC.
    Apmis 03/2014; · 2.07 Impact Factor
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    ABSTRACT: This retrospective study assessed the clinical outcome of a transjugular intrahepatic portosystemic shunt (TIPS) procedure for managing portal hypertension in Koreans with liver cirrhosis. Between January 2003 and July 2013, 230 patients received a TIPS in 13 university-based hospitals. Of the 229 (99.6%) patients who successfully underwent TIPS placement, 142 received a TIPS for variceal bleeding, 84 for refractory ascites, and 3 for other indications. The follow-up period was 24.9±30.2 months (mean±SD), 74.7% of the stents were covered, and the primary patency rate at the 1-year follow-up was 78.7%. Hemorrhage occurred in 30 (21.1%) patients during follow-up; of these, 28 (93.3%) cases of rebleeding were associated with stent dysfunction. Fifty-four (23.6%) patients developed new hepatic encephalopathy, and most of these patients were successfully managed conservatively. The cumulative survival rates at 1, 6, 12, and 24 months were 87.5%, 75.0%, 66.8%, and 57.5%, respectively. A high Model for End-Stage Liver Disease (MELD) score was significantly associated with the risk of death within the first month after receiving a TIPS (P=0.018). Old age (P<0.001), indication for a TIPS (ascites vs. bleeding, P=0.005), low serum albumin (P<0.001), and high MELD score (P=0.006) were associated with overall mortality. A high MELD score was found to be significantly associated with early and overall mortality rate in TIPS patients. Determining the appropriate indication is warranted to improve survival in these patients.
    Clinical and molecular hepatology. 03/2014; 20(1):18-27.
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    Woo Jin Chung
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    ABSTRACT: A major cause of cirrhosis related morbidity and mortality is the development of variceal bleeding, a direct consequence of portal hypertension. Less common causes of gastrointestinal bleeding are peptic ulcers, malignancy, angiodysplasia, etc. Upper gastrointestinal bleeding has been classified according to the presence of a variceal or non-variceal bleeding. Although non-variceal gastrointestinal bleeding is not common in cirrhotic patients, gastroduodenal ulcers may develop as often as non-cirrhotic patients. Ulcers in cirrhotic patients may be more severe and less frequently associated with chronic intake of non-steroidal anti-inflammatory drugs, and may require more frequently endoscopic treatment. Portal hypertensive gastropathy (PHG) refers to changes in the mucosa of the stomach in patients with portal hypertension. Patients with portal hypertension may experience bleeding from the stomach, and pharmacologic or radiologic interventional procedure may be useful in preventing re-bleeding from PHG. Gastric antral vascular ectasia (GAVE) seems to be different disease entity from PHG, and endoscopic ablation can be the first-line treatment.
    Clinical and molecular hepatology. 03/2014; 20(1):1-5.
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    ABSTRACT: Sulfur-rich copolymers based on poly(sulfur-random-1,3-diisopropenylbenzene) (poly(S-r-DIB)) were synthesized via inverse vulcanization to create cathode materials for lithium–sulfur battery applications. These materials exhibit enhanced capacity retention (1005 mAh/g at 100 cycles) and battery lifetimes over 500 cycles at a C/10 rate. These poly(S-r-DIB) copolymers represent a new class of polymeric electrode materials that exhibit one of the highest charge capacities reported, particularly after extended charge–discharge cycling in Li–S batteries.
    ACS Macro Letters. 02/2014; 3(3):229–232.
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    ABSTRACT: G protein‐coupled receptor (GPCR) cell signalling cascades are initiated upon binding of a specific agonist ligand to its cell surface receptor. Linking multiple heterologous ligands that simultaneously bind and potentially link different receptors on the cell surface is a unique approach to modulate cell responses. Moreover, if the target receptors are selected based on analysis of cell‐specific expression of a receptor combination, then the linked binding elements might provide enhanced specificity of targeting the cell type of interest, that is, only to cells that express the complementary receptors. Two receptors whose expression is relatively specific (in combination) to insulin‐secreting pancreatic β‐cells are the sulfonylurea‐1 (SUR1) and the glucagon‐like peptide‐1 (GLP‐1) receptors. A heterobivalent ligand was assembled from the active fragment of GLP‐1 (7–36 GLP‐1) and glibenclamide, a small organic ligand for SUR1. The synthetic construct was labelled with Cy5 or europium chelated in DTPA to evaluate binding to β‐cells, by using fluorescence microscopy or time‐resolved saturation and competition binding assays, respectively. Once the ligand binds to β‐cells, it is rapidly capped and presumably removed from the cell surface by endocytosis. The bivalent ligand had an affinity approximately fivefold higher than monomeric europium‐labelled GLP‐1, likely a result of cooperative binding to the complementary receptors on the βTC3 cells. The high‐affinity binding was lost in the presence of either unlabelled monomer, thus demonstrating that interaction with both receptors is required for the enhanced binding at low concentrations. Importantly, bivalent enhancement was accomplished in a cell system with physiological levels of expression of the complementary receptors, thus indicating that this approach might be applicable for β‐cell targeting in vivo.
    ChemBioChem 01/2014; 15(1). · 3.74 Impact Factor
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    ABSTRACT: Irisin is a recently found myokine that aids obesity control and improves glucose homeostasis by acting on white adipose tissue cells and increases total energy consumption. The aim of this study was to evaluate serum irisin levels in patients with non-alcoholic fatty liver disease (NAFLD) and to compare these levels with those of normal controls. Among 595 health screen examinees who had visited our institute between January 2013 to March 2013, 355 patients (84 NAFLD patients and 271 normal controls) were enrolled depending on whether they gave written informed consents and their history of alcohol intake, blood tests, and abdominal ultrasonographic findings. Age; sex; laboratory test parameters; homeostasis model assessment-insulin resistance; and levels of leptin, adiponectin, and irisin were assessed. Serum irisin levels (ng/ml) were significantly higher in the NAFLD group than in normal controls (63.4±32.6 vs. 43.0±29.7, p<0.001) and higher in the mild fatty liver group than in the moderate-to-severe fatty liver group (68.3±38.2 vs. 56.6±21.2, p<0.001). Additionally, serum irisin levels were not different between the non-obese and obese groups (48.4±34.2 vs. 45.8±22.9, p = 0.492); however, the levels were significantly lowest in normal controls and highest in the mild fatty liver group in the non-obese (44.9±31.7 vs. 73.1±48.5 vs 59.7±18.0, p<0.001) and obese groups (35.0±17.0 vs. 62.9±21.2 vs. 54.6±23.3, p<0.001). Serum irisin levels were significantly higher in NAFLD patients, which is not consistent with the results of previously published studies. Therefore, more studies are needed to confirm the role of irisin in NAFLD.
    PLoS ONE 01/2014; 9(10):e110680. · 3.53 Impact Factor
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    ABSTRACT: Defects of autophagy and endoplasmic reticulum (ER) stress are related to many diseases and tumors. However, only a few studies have examined hepatocellular carcinoma (HCC) as related to these processes. Therefore, in this study, we investigated the expression and extent of autophagy and ER stress-related markers in HCC and their influence on clinical characteristics and prognosis for each protein. The expression of autophagy-related markers (LC3 and Beclin-1) and ER stress-related markers (GRP78 and CHOP) was analyzed by immunohistochemistry on tissues from completely resected specimens of 190 HCC patients. Their influence on clinicopathologic features and prognosis were evaluated using the chi-square test and Kaplan-Meier analysis. Correlations of each protein were determined by Spearman's correlation analysis. LC3 expression was not correlated with TNM, BCLC stage, or Edmonson-Steiner grading, whereas it was correlated with longer overall survival (OS) (p = 0.039) and tended to be related with longer time to recurrence (TTR) (p=0.068) although it did not show statistical significance. Multivariate analysis indicated that LC3 expression was a significantly independent prognostic factor of OS (HR, 0.42; 95% CI, 0.22-0.80; p-value=0.009) and TTR (HR, 0.54; 95% CI, 0.33-0.90; p=0.017). Expression of LC3 in advanced stages of TNM (III) (p=0.045) and Edmonson-Steiner Grades (III and IV) (p=0.043) was correlated with longer survival, but not in the early stages. A positive correlation was not observed between the expression of autophagy-related markers and ER stress-related markers. Our results suggest that the expression and extent of LC3 might be a strong prognostic factor of HCC, especially in patients with surgical resection.
    PLoS ONE 12/2013; 8(11):e81540. · 3.53 Impact Factor
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    ABSTRACT: The results of studies that evaluated predictive factors for rebleeding in non-variceal upper gastrointestinal bleeding are inconsistent. The aim of this study was to investigate predictive factors for 30-day rebleeding in these patients. A consecutive 312 patients presenting symptoms and signs of gastrointestinal bleeding were enrolled in this prospective, observational study. Clinical and demographic characteristics and endoscopic findings were evaluated for potential factors associated with 30-day rebleeding using logistic regression analysis. Overall, 176 patients were included (male, 80.1%; mean age, 59.7±16.0 yr). Rebleeding within 7 and 30 days occurred in 21 (11.9%) and 27 (15.3%) patients, respectively. We found that chronic kidney disease (CKD) (OR, 10.29; 95% CI, 2.84-37.33; P<0.001), tachycardia (pulse>100 beats/min) during the admission (OR, 3.79; 95% CI, 1.25-11.49; P=0.019), and Forrest classes I, IIa, and IIb (OR, 6.14; 95% CI, 1.36-27.66; P=0.018) were significant independent predictive factors for 30-day rebleeding. However, neither Rockall nor Blatchford scores showed statistically significant relationships with 30-day rebleeding in a multivariate analysis. CKD, hemodynamic instability during hospitalization, and an endoscopic high-risk appearance are significantly independent predictors of 30-day rebleeding in patients with non-variceal upper gastrointestinal bleeding. These factors may be useful for clinical management of such patients.
    Journal of Korean medical science 10/2013; 28(10):1500-6. · 0.84 Impact Factor
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    ABSTRACT: The synthesis and thermomechanical properties of a novel class of self-healing perfluoropolyethers (PFPEs) is reported. By decoration of 2-ureido-4[1H]-pyrimidone end groups on the termini of low molar mass PFPE, the formation of supramolecular polymers and networks held together via hydrogen bonding associations was achieved. These novel supramolecular polymer materials exhibit a combination of enhanced modulus and elasticity, along with self-healing properties, where rapid self-healing time was demonstrated using dynamic rheological measurements. These types of supramolecular PFPEs are anticipated to be useful for a number of emerging areas in lubrication. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3598–3606
    Journal of Polymer Science Part A Polymer Chemistry 09/2013; 51(17):3598-3606. · 3.54 Impact Factor
  • Woo Jin Chung
    The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 07/2013; 62(1):78-81.
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    ABSTRACT: The environmental factors human rhinoviruses (HRVs) and house dust mites (HDMs) are the most common causes of acute exacerbations of asthma. The aim of this study was to compare the chemokine production induced by HRVs in airway epithelial cells with that induced by other respiratory viruses, and to investigate synergistic interactions between HRVs and HDMs on the induction of inflammatory chemokines in vitro. A549 human airway epithelial cells were infected with either rhinovirus serotype 7, respiratory syncytial virus (RSV)-A2 strain, or adenovirus serotype 3 and analyzed for interleukin (IL)-8 and regulated on activation, normal T-cell expressed and secreted (RANTES) release and mRNA expression. Additionally, activation of nuclear factor (NF)-κB and activator protein (AP)-1 were evaluated. The release of IL-8 and RANTES was also measured in cells stimulated simultaneously with a virus and the HDM allergen, Der f1. HRV caused greater IL-8 and RANTES release and mRNA expression compared with either RSV or adenovirus. NF-κB and AP-1 were activated in these processes. Cells incubated with a virus and Der f1 showed an increased IL-8 release. However, compared with cells incubated with virus alone as the stimulator, only HRV with Der f1 showed a statistically significant increase. IL-8 and RANTES were induced to a greater extent by HRV compared with other viruses, and only HRV with Der f1 acted synergistically to induce bronchial epithelial IL-8 release. These findings may correspond with the fact that rhinoviruses are identified more frequently than other viruses in cases of acute exacerbation of asthma.
    Allergy, asthma & immunology research 07/2013; 5(4):216-23. · 2.65 Impact Factor
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    ABSTRACT: The synthesis of single chain nanoparticles has been achieved by the synthesis of a linear polystyrenic precursor carrying 3,4-propylenedioxythiophene groups via atom transfer radical polymerization followed by intramolecular crosslinking via oxidative polymerization. This methodology enabled the introduction of electroactive inclusions into single chain polymer nanoparticles, while concurrently promoting intramolecular collapse.
    Polym. Chem. 06/2013; 4(13):3765-3773.
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    ABSTRACT: An excess of elemental sulfur is generated annually from hydrodesulfurization in petroleum refining processes; however, it has a limited number of uses, of which one example is the production of sulfuric acid. Despite this excess, the development of synthetic and processing methods to convert elemental sulfur into useful chemical substances has not been investigated widely. Here we report a facile method (termed 'inverse vulcanization') to prepare chemically stable and processable polymeric materials through the direct copolymerization of elemental sulfur with vinylic monomers. This methodology enabled the modification of sulfur into processable copolymer forms with tunable thermomechanical properties, which leads to well-defined sulfur-rich micropatterned films created by imprint lithography. We also demonstrate that these copolymers exhibit comparable electrochemical properties to elemental sulfur and could serve as the active material in Li-S batteries, exhibiting high specific capacity (823 mA h g(-1) at 100 cycles) and enhanced capacity retention.
    Nature Chemistry 06/2013; 5(6):518-24. · 21.76 Impact Factor

Publication Stats

331 Citations
195.83 Total Impact Points

Institutions

  • 2005–2014
    • Keimyung University
      • Dongsan Medical Center
      Sŏul, Seoul, South Korea
    • Yonsei University Hospital
      Sŏul, Seoul, South Korea
  • 2009–2013
    • The University of Arizona
      • Department of Chemistry and Biochemistry (College of Science)
      Tucson, Arizona, United States
  • 2010
    • Massachusetts General Hospital
      • Department of Medicine
      Boston, MA, United States
    • Harvard Medical School
      • Department of Medicine
      Boston, Massachusetts, United States
  • 2006
    • Kyung Hee University
      • College of Medicine
      Seoul, Seoul, South Korea
  • 2003–2004
    • Yonsei University
      • Graduate School of Public Health
      Sŏul, Seoul, South Korea