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Featured researches published by Sei Jin Youn.


Gastrointestinal Endoscopy | 2009

A new technique for gastric endoscopic submucosal dissection: peroral traction-assisted endoscopic submucosal dissection

Won Joong Jeon; Il Young You; Hee Bok Chae; Seon Mee Park; Sei Jin Youn

BACKGROUND Compared with conventional EMR, endoscopic submucosal dissection (ESD) has a higher en bloc resection rate and complete resection rate, regardless of tumor size, in treating gastric neoplasms. However, ESD leads to more complications, such as bleeding or perforation, and, in particular, needs more procedure time than a conventional EMR. OBJECTIVE To report a new technique for ESD, peroral traction-assisted ESD with suture material, to perform easier and more rapid procedures in treating gastric neoplasms and to report the techniques early results. DESIGN A case series. SETTING A tertiary medical center. PATIENTS AND METHODS A total of 15 patients with gastric adenomas or early gastric cancers larger than 10 mm in diameter were consecutively enrolled. After marking around the periphery of the lesion, submucosal injection, followed by circumferential mucosal incision with a Flex-knife and an insulation-tipped knife, was conducted. After that, one hemostatic clip, tied by using a white silk suture, was applied at a site of the lesion suitable for oral traction. During submucosal dissection, the applied suture material was pulled to the oral side. Additional tractions were applied as needed. MAIN OUTCOME MEASUREMENTS En bloc resection rate, procedure time, complications. RESULTS All lesions were resected en bloc with free lateral and vertical margins by using this technique. The mean longest lesion size and specimen size were 18.1 mm (range 11-28 mm) and 43.7 mm in diameter (range 25-64 mm), respectively. The mean procedure time was 49.6 minutes (range 28-90 minutes). There was no significant bleeding that required blood transfusion or perforation related to the procedures. LIMITATIONS Single endoscopist, small patient number. CONCLUSION Peroral traction-assisted ESD with suture material is useful in treating gastric neoplasms located in various regions of the stomach. It may make ESD procedures easier, faster, and safer under better direct vision of the submucosal layer.


Journal of Histochemistry and Cytochemistry | 2004

An Immunohistochemical Study of the Expression of Adhesion Molecules in Gallbladder Lesions

Yoon-La Choi; Yan Hua Xuan; Young Kee Shin; Seoung Wan Chae; Myeong Cherl Kook; Ro Hyun Sung; Sei Jin Youn; Jae Woon Choi; Seok Hyung Kim

We investigated the expression of 10 adhesion molecules (α-catenin, β-cate-nin, γ-catenin, CD44, CD44v6, ICAM-1, CD56, CEA, E-cadherin, and CD99) in 46 gallbladder carcinomas, 14 adenomas, 15 low-grade dysplasias, nine intestinal metaplasias, and 20 samples of normal gallbladder epithelium by immunohistochemistry. The expression of adhesion molecules was altered in gallbladder carcinomas and adenomas. In gallbladder carcinomas, increased expression of ICAM-1, CEA, and CD44v6 was observed, together with decreased expression of α/β/γ-catenin and CD99. In adenomas, aberrant expression of CD44v6 and CD56, as well as reduced expression of α/β/γ- and E-cadherins, was noted. Expression of α/β/γ-catenin was reduced in low-grade dysplasia, whereas there was no change in the expression of these adhesion molecules in metaplasia. Expression of ICAM-1, CD99, E-cadherin, and CD56 was correlated with clinical stage. In addition a correlation was noted between expression of ICAM-1 and E-cadherin and lymph node metastasis (p<0.05). These results suggest that altered expression of these adhesion molecules is involved in the progression and metastasis of gallbladder carcinomas.


Diagnostic Pathology | 2013

Combined aberrant expression of E-cadherin and S100A4, but not β-catenin is associated with disease-free survival and overall survival in colorectal cancer patients

Sang-Jeon Lee; Song Yi Choi; Wun-Jae Kim; Meiying Ji; Taek-Gu Lee; Bo-Ra Son; Soon Man Yoon; Rohyun Sung; Eun Jeoung Lee; Sei Jin Youn; Seon Mee Park

Background/AimsEpithelial-to-mesenchymal transition (EMT) in cancers is related to metastasis, recurrence, and poor prognosis. We evaluated whether EMT-related proteins can act as prognostic biomarkers in colorectal cancer (CRC) patients.MethodsWe evaluated the expression of E-cadherin, β-catenin, and S100A4 by immunohistochemistry (IHC) in 333 CRC tissues from the tumor center and invasive margin. Tumor budding, cell grade, tumor stage, type of tumor growth, peritumoral lymphocyte infiltration (TLI), and perineural- or lymphovascular invasion were evaluated as pathological parameters. mRNA levels of E-cadherin, N-cadherin, β-catenin, and S100A4 from 68 specimens from the same set were analyzed by real time quantitative RT-PCR.ResultsLoss of E-cadherin, nuclear β-catenin, and gain of S100A4 were higher in the invasive margin than in the tumor center. Loss of E-cadherin was associated with cell grade, macroscopic type, perineural invasion, and tumor budding, β-catenin with microsatellite instability and tumor site, and S100A4 with growth type, macroscopic type, AJCC stage, lymphovascular invasion, and perineural invasion. The aberrant expression of E-cadherin and S100A4 not β-catenin in the invasive margin was a significant and independent risk factor for disease-free and overall-survival by multivariate analysis, along with AJCC stage and perineural invasion. mRNA levels of β-catenin and S100A4 were correlated with the IHC findings at the tumor invasive margin. E-cadherin and N-cadherin showed a weak inverse correlation.ConclusionsThe combination of loss of E-cadherin and gain of S100A4 in the tumor invasive margin can be used to stratify patients with the same AJCC stage into different survival groups.Virtual slidesThe virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9398289629244673


The Scientific World Journal | 2013

Direct-Acting Antivirals for the Treatment of Chronic Hepatitis C: Open Issues and Future Perspectives

Hee Bok Chae; Seon Mee Park; Sei Jin Youn

Currently, two direct-acting antivirals (DAAs) show well-established efficacy against hepatitis C virus (HCV), namely, first-wave protease inhibitors telaprevir and boceprevir. Most clinical trials have examined DAAs in combination with standard of care (SOC) regimens. Future therapeutic drugs were divided into three categories. They are second-wave protease inhibitors, second-generation protease inhibitors, and polymerase inhibitors. Second-wave protease inhibitors are more improved form and can be administered once a day. Oral drug combinations can be favored because interferon (IFN) not only has to be given as intradermal injection, but also can cause several serious side effects. Combination of drugs with different mechanisms shows a good sustained virological response (SVR). But several mutations are associated with viral resistance to DAAs. Therefore, genotypic resistance data may provide insights into strategies aimed at maximizing SVR rates and minimizing resistance. Combined drug regimens are necessary to prevent the emergence of drug-resistant HCV. Many promising DAA candidates have been identified. Of these, a triple regimen containing sofosbuvir shows promise, and treatment with daclatasvir plus asunaprevir yields a high SVR rate (95%). Oral drug combinations will be standard of care in the near future.


The Korean Journal of Internal Medicine | 2001

Is Cholecystectomy Necessary After ERCP for Bile Duct Stones in Patients with Gallbladder in situ

Soon Kil Kwon; Byung Seok Lee; Nam Jae Kim; Heon Young Lee; Hee Bok Chae; Sei Jin Youn; Seon Mee Park

Background The requirement for subsequent cholecystectomy in patients with gallbladder in situ after endoscopic removal of stones from the common bile duct (CBD) is controversial. The aims of this study were to assess the requirement for subsequent cholecystectomy for gallbladder-related symptoms, and to identify the patients who develop symptoms after the endoscopic removal of CBD stones. Methods Of 241 patients with gallbladder in situ following endoscopic removal of stones from the CBD, 146 patients (78 men and 68 women; mean age 69±13 years, range 20–93) with a follow-up time of more than three months without elective cholecystectomy were enrolled in the study. Fifty-nine patients had gallbladder stones (single stones in 27 and multiple stones in 32) and 87 patients had gallbladder in situ without stones. The time from entry to the occurrences of death or cholecystectomy was evaluated retrospectively. Cox regression analysis was used to evaluate the risk factors associated with these events. Results The mean duration of follow-up was 24.1±18.0 months (range 3–70 months). During follow-up, seven patients (4.8%) underwent cholecystectomy, on average 18.4 months after CBD stone removal, as the result of acute cholecystitis in four cases, biliary pain in two cases and acute pancreatitis in one case. Laparoscopic cholecystectomy was performed in four patients and open cholecystectomy in three patients. Post-operative morbidity occurred in two patients, with improvement after conservative management. Nine patients (6.2%) died as the result of unrelated biliary disease. Age, sex, presence of gallbladder stones, multiplicity of gallbladder stones and underlying disease did not correlate with subsequent cholecystectomy by Cox regression analysis. Conclusion Elective cholecystectomy is not warranted in patients with bile duct stones when the common duct can be cleared of stones by endoscopic sphincterotomy. We could not find any clinical predictors of further symptoms or complications arising from the retained gallbladder.


Clinical Endoscopy | 2014

Endoscopy for nonvariceal upper gastrointestinal bleeding.

Ki Bae Kim; Soon Man Yoon; Sei Jin Youn

Endoscopy for acute nonvariceal upper gastrointestinal bleeding plays an important role in primary diagnosis and management, particularly with respect to identification of high-risk stigmata lesions and to providing endoscopic hemostasis to reduce the risk of rebleeding and mortality. Early endoscopy, defined as endoscopy within the first 24 hours after presentation, improves patient outcome and reduces the length of hospitalization when compared with delayed endoscopy. Various endoscopic hemostatic methods are available, including injection therapy, mechanical therapy, and thermal coagulation. Either single treatment with mechanical or thermal therapy or a treatment that combines more than one type of therapy are effective and safe for peptic ulcer bleeding. Newly developed methods, such as Hemospray powder and over-the-scope clips, may provide additional options. Appropriate decisions and specific treatment are needed depending upon the conditions.


World Journal of Gastroenterology | 2013

Efficacy of cap-assisted endoscopy for routine examining the ampulla of Vater

Young Rak Choi; Joung-Ho Han; Young Shim Cho; Hye-Suk Han; Hee Bok Chae; Seon Mee Park; Sei Jin Youn

AIM To determine the efficacy of a cap-assisted endoscopy (CAE) to completely visualize the ampulla of Vater (AV) in patients failed by conventional endoscopy. METHODS A prospective study was conducted on 120 patients > 20 years of ages who visited the Health Promotion Center of Chungbuk National University Hospital for conscious sedation esophagogastroduodenoscopy (EGD) as a screening test from July to October, 2011. First, forward-viewing endoscopy was performed with reasonable effort using a push and pull method. We considered complete visualization of the AV when we could observe the entire AV including the orifice clearly, and reported the observation as complete or incomplete (partial or not found at all). Second, in cases of complete failure of the observation, an additional AV examination was conducted by attaching a short cap (D-201-10704, Olympus Medical Systems, Tokyo, Japan) to the tip of a forward-viewing endoscope. Third, if the second method failed, we replaced the short cap with a long cap (MH-593, Olympus Medical Systems) and performed a re-examination of the AV. RESULTS Conventional endoscopy achieved complete visualization of the AV in 97 of the 120 patients (80.8%) but was not achieved in 23 patients (19.2%). Age (mean ± SD) and gender [male (%)] were not significantly different between the complete observation and the incomplete observation groups. Additional short CAE was performed in patients in whom we could not completely visualize the AV. This group included 13 patients (10.9%) with partial observation of the AV and 10 (8.3%) in which the AV was not found. Short CAE permitted a complete observation of the AV in 21 of the 23 patients (91.3%). Patients in whom visualization of the AV failed with short CAE had satisfactory outcomes by replacing the short cap with a long cap. The additional time for CAE took an average of 141 ± 88 s. There were no complications and no significant mucosal trauma. CONCLUSION CAE is safe to use as a salvage method to achieve complete visualization of the AV when a regular EGD examination fails.


The Korean Journal of Hepatology | 2012

High efficacy of adefovir and entecavir combination therapy in patients with nucleoside-refractory hepatitis B.

Hee Bok Chae; Mee Jin Kim; Eui Geun Seo; Yong Hyeok Choi; Hee Seung Lee; Joung-Ho Han; Soon Man Yoon; Seon Mee Park; Sei Jin Youn

Background/Aims Newly developed and potent antiviral agents suffer from the problem of drug resistance. Multidrug resistance is a major impediment in the treatment of patients with chronic hepatitis B (CHB). In line with American Association for the Study of Liver Diseases guidelines, adefovir dipivoxil (ADV) add-on therapy is recommended in the case of lamivudine resistance, while tenofovir disoproxil fumarate (TDF) is recommended for ADV or entecavir (ETV) resistance. TDF is currently not available in Korea. ADV+ETV combination therapy may be a viable alternative to TDF in patients with either ADV or ETV resistance. However, the efficacy of ADV+ETV combination therapy in patients with CHB and multidrug resistance is unclear. This study investigated the efficacy of ADV+ETV combination therapy in patients with multidrug resistance. Methods Twenty-five patients were enrolled and were administered ADV+ETV combination therapy for at least 6 months. Blood was drawn at baseline and at 3, 6, 9, and 12 months after commencing treatment, and the following blood parameters were analyzed: alanine transaminase, hepatitis B e-antigen (HBeAg), anti-hepatitis B e-antigen, and hepatitis B virus (HBV) DNA levels. The initial virological response (IVR) was defined as an HBV DNA level of <4 log10 copies/mL after 6 months of combination therapy. Results The IVR rate was 76%. The proportion of patients with a high viral load (≥5.0 log) dropped from 76% at baseline to only 5% after 6 months of treatment. The biochemical response rate during the first 6 months was 71%. HBeAg was lost in 2 patients (10%). Conclusions ADV+ETV combination therapy induced a good IVR in CHB patients who were refractory to more than 2 antiviral agents. This regimen may be a good alternative to TDF in Korea, where that drug is not available.


Journal of Korean Medical Science | 2010

Cholestatic Hepatitis and Thrombocytosis in a Secondary Syphilis Patient

Byeong Uk Kim; Ju Hee Lee; Yong Heok Choi; Hee Bok Chae; Seon Mee Park; Sei Jin Youn; Ji Yeoun Lee; Tae Young Yoon; Rohyun Sung

The incidence of acute hepatitis in syphilis patient is rare. First of all, our patient presented with hepatitis comorbid with thrombocytosis. To our knowledge, this is only the second report of syphilitic hepatitis with thrombocytosis. The 42-yr-old male complained of flulike symptoms and skin eruptions on his palms and soles. Laboratory findings suggested an acute hepatitis and thrombocytosis. Serologic test results were positive for VDRL. He recovered from his symptoms and elevated liver related enzymes with treatment. Because syphilitic hepatitis can present without any typical signs of accompanying syphilis, syphilis should be considered as a possible cause in acute hepatitis patients.


Journal of Korean Medical Science | 2013

Podoplanin, α-Smooth Muscle Actin or S100A4 Expressing Cancer-Associated Fibroblasts Are Associated with Different Prognosis in Colorectal Cancers

Song-Yi Choi; Rohyun Sung; Sang-Jeon Lee; Taek-Gu Lee; Nayoung Kim; Soon Man Yoon; Eun Jeoung Lee; Hee Bok Chae; Sei Jin Youn; Seon Mee Park

The interactions between the tumor microenvironment and tumor cells determine the behavior of the primary tumors. Whether cancer-associated fibroblasts (CAF) have a tumor progressive or a protective role likely depends on the type of tumor cells and the CAF subpopulation. In the present study, we analyzed the prognostic significance of CAF subpopulations in colorectal cancer (CRC). CAF phenotypes were analyzed in 302 CRC patients by using antibodies against podoplanin (PDPN), α-smooth muscle actin (α-SMA), and S100A4. The relationship between the CAF phenotypes and 11 clinicopathological parameters were evaluated and their prognostic significance was analyzed from the disease-free and overall survival times. We observed that at the tumor invasive front, PDPN CAFs were present in 40% of the cases, and S100A4 or α-SMA CAFs were detected in all the cases. PDPN/S100A4 and α-SMA/S100A4 dual-stained CAFs were observed in 10% and 40% of the cases, respectively. The PDPN+ CAFs were associated with 6 favorable clinicopathological parameters and prolonged disease-free survival time. The PDPN-/α-SMAhigh CAFs were associated with 6 aggressive clinicopathological parameters and tended to exhibit shorter disease-free survival time. On the other hand, the PDPN-/S100A4high CAFs were associated with 2 tumor progression parameters, but not with disease prognosis. The PDPN+ CAF phenotype is distinct from the α-SMA or S100A4 CAFs in that it is associated with less aggressive tumors and a favorable prognosis, whereas the PDPN-/α-SMAhigh or PDPN-/S100A4high CAFs are associated with tumor progression in CRC. These findings suggest that CAFs can be a useful prognostic biomarker or potential targets of anti-cancer therapy in CRC.

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Seon Mee Park

Chungbuk National University

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Hee Bok Chae

Chungbuk National University

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Joung-Ho Han

Chungbuk National University

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Soon Man Yoon

Chungbuk National University

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Won Joong Jeon

Chungbuk National University

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Rohyun Sung

Chungbuk National University

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Ki Bae Kim

Chungbuk National University

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Young Shim Cho

Chungbuk National University

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Byeong Uk Kim

Chungbuk National University

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Hee Seung Lee

Chungbuk National University

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