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Dive into the research topics where Semi Park is active.

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Featured researches published by Semi Park.


Gastrointestinal Endoscopy | 2010

Active locomotion of a paddling-based capsule endoscope in an in vitro and in vivo experiment (with videos)

Hee Man Kim; Sungwook Yang; Jinseok Kim; Semi Park; Jae Hee Cho; Jeong Youp Park; Tae Song Kim; Eui-Sung Yoon; Si Young Song; Seungmin Bang

BACKGROUND Capsule endoscopy that could actively move and approach a specific site might be more valuable for the diagnosis or treatment of GI diseases. OBJECTIVE We tested the performance of active locomotion of a novel wired capsule endoscope with a paddling-based locomotion mechanism, using 3 models: a silicone tube, an extracted porcine colon, and a living pig. DESIGN In vitro, ex vivo, and in vivo experiments in a pig model. SETTING Study in an animal laboratory. INTERVENTIONS For the in vitro test, the locomotive capsule was controlled to actively move from one side of a silicone tube to the other by a controller-operated automatic traveling program. The velocity was calculated by following a video recording. We performed ex vivo tests by using an extracted porcine colon in the same manner we performed the in vitro test. In in vivo experiments, the capsule was inserted into the rectum of a living pig under anesthesia, and was controlled to move automatically forward. After 8 consecutive trials, the velocity was calculated. MAIN OUTCOME MEASUREMENTS Elapsed time, velocity, and mucosal damage. RESULTS The locomotive capsule showed stable and active movement inside the lumen both in vitro and ex vivo. The velocity was 60 cm/min in the silicone tube, and 36.8 and 37.5 cm/min in the extracted porcine colon. In the in vivo experiments, the capsule stably moved forward inside the colon of a living pig without any serious complications. The mean velocity was 17 cm/min over 40 cm length. We noted pinpoint erythematous mucosal injuries in the colon. LIMITATION Porcine model experiments, wired capsule endoscope. CONCLUSIONS The novel paddling-based locomotive capsule endoscope performed fast and stable movement in a living pig colon with consistent velocity. Further investigation is necessary for practical use in humans.


Gastrointestinal Endoscopy | 2010

Comparison of efficacies between stents for malignant colorectal obstruction: a randomized, prospective study

Semi Park; Jae Hee Cheon; Jae Jun Park; Chang Mo Moon; Sung Pil Hong; Sang Kil Lee; Tae Il Kim; Won Ho Kim

BACKGROUND Colonoscopic insertion of a self-expandable metallic stent (SEMS) has been widely performed for the treatment of malignant colorectal obstruction. Different types of stents could influence the efficacy and complication rate of stent use. OBJECTIVE To compare the efficacy and complication rates between two SEMSs, the uncovered WallFlex stent and the covered Comvi stent. DESIGN A prospective, randomized study. SETTING Tertiary-care academic medical center. PATIENTS Between 2007 and 2009, a total of 151 patients with malignant colorectal obstruction were enrolled. INTERVENTION Two types of colorectal SEMSs (the uncovered WallFlex stent by Boston Scientific Corp and the newly developed covered Comvi stent by Taewoong Medical Co) were inserted. MAIN OUTCOME MEASUREMENTS Technical success, clinical success, stent patency, and complication rate according to stent type. RESULTS Technical failure occurred in 2 patients (1.3%); one was in the WallFlex group and the other in the Comvi group. Clinical failure developed in 9 patients (6.0%): 6 patients from the WallFlex group and 3 from the Comvi group. Complications because of cancer infiltration occurred more frequently in the WallFlex group (14.5% vs 3.8%). However, the rate of stent migration was higher in the Comvi group (21.1% vs 1.8%). The mean patency of the stent did not differ between the two groups (P = .50). LIMITATIONS This was a single-center study. CONCLUSION Both uncovered WallFlex and covered Comvi stents were suitable for relieving malignant colorectal obstruction. Tumor ingrowth was more common in the WallFlex group, but stent migration was more common in the Comvi group.


Gut and Liver | 2010

A Pilot Study of Sequential Capsule Endoscopy Using MiroCam and PillCam SB Devices with Different Transmission Technologies.

Hee Man Kim; Yoon Jae Kim; Hong Jeong Kim; Semi Park; Jeong Youp Park; Sung Kwan Shin; Jae Hee Cheon; Sang Kil Lee; Yong Chan Lee; Seung Woo Park; Seungmin Bang; Si Young Song

BACKGROUND/AIMS Studies have investigated the use of different types of radiofrequency capsules for comparison or sequential capsule endoscopy, but none have compared the MiroCam device - which utilizes a novel data transmission technology - with other capsules. This study compared the feasibility of sequential capsule endoscopy using the MiroCam and PillCam SB devices, which employ different transmission technologies. METHODS Patients with diseases requiring capsule endoscopy were enrolled. After a 12-hour fast, one randomly selected capsule was swallowed. The second capsule was swallowed once fluoroscopy had indicated that the first capsule had migrated below the gastric outlet. RESULTS The total operating time in 24 patients was 702+/-60 min (mean+/-SD) for the MiroCam and 446+/-28 min for the PillCam SB (p<0.0001). The rate of a complete examination to the cecum was 83.3% for the MiroCam and 58.3% for the PillCam SB (p=0.031). Diagnostic yields for the MiroCam, PillCam SB, and sequential capsule endoscopy were 45.8%, 41.7%, and 50.0%, respectively. The agreement rate between the two capsules was 87.5%, with a kappa value of 0.74. Electrical interference in data transmission between the two capsules was not observed, but temporary visual interferences were observed in seven patients (29.2%). CONCLUSIONS Sequential capsule endoscopy with the MiroCam and PillCam SB produced slight but nonsignificant increases in the diagnostic yield, and the two capsules did not exhibit electrical interference. A larger trial is necessary for elucidating the usefulness of sequential capsule endoscopy.


Gastrointestinal Endoscopy | 2010

Original articleClinical endoscopyComparison of efficacies between stents for malignant colorectal obstruction: a randomized, prospective study

Semi Park; Jae Hee Cheon; Jae Jun Park; Chang Mo Moon; Sung Pil Hong; Sang-Kil Lee; Tae Il Kim; Won Ho Kim

BACKGROUND Colonoscopic insertion of a self-expandable metallic stent (SEMS) has been widely performed for the treatment of malignant colorectal obstruction. Different types of stents could influence the efficacy and complication rate of stent use. OBJECTIVE To compare the efficacy and complication rates between two SEMSs, the uncovered WallFlex stent and the covered Comvi stent. DESIGN A prospective, randomized study. SETTING Tertiary-care academic medical center. PATIENTS Between 2007 and 2009, a total of 151 patients with malignant colorectal obstruction were enrolled. INTERVENTION Two types of colorectal SEMSs (the uncovered WallFlex stent by Boston Scientific Corp and the newly developed covered Comvi stent by Taewoong Medical Co) were inserted. MAIN OUTCOME MEASUREMENTS Technical success, clinical success, stent patency, and complication rate according to stent type. RESULTS Technical failure occurred in 2 patients (1.3%); one was in the WallFlex group and the other in the Comvi group. Clinical failure developed in 9 patients (6.0%): 6 patients from the WallFlex group and 3 from the Comvi group. Complications because of cancer infiltration occurred more frequently in the WallFlex group (14.5% vs 3.8%). However, the rate of stent migration was higher in the Comvi group (21.1% vs 1.8%). The mean patency of the stent did not differ between the two groups (P = .50). LIMITATIONS This was a single-center study. CONCLUSION Both uncovered WallFlex and covered Comvi stents were suitable for relieving malignant colorectal obstruction. Tumor ingrowth was more common in the WallFlex group, but stent migration was more common in the Comvi group.


Yonsei Medical Journal | 2010

Gastropericardial Fistula as a Complication in a Refractory Gastric Ulcer after Esophagogastrostomy with Gastric Pull-Up

Semi Park; Jie Hyun Kim; Yong Chan Lee; Jae Bock Chung

A gastropericardial fistula, defined as penetration of a gastric lesion into the pericardium, is a rare occurrence. Such a fistula is usually associated with a huge ulcer in the gastric fundus, an ulcer within a hiatus hernia, a history of esophagogastric surgery, the concurrent use of non-steroidal anti-inflammatory drugs (NSAIDs), or Zollinger-Ellison syndrome. The patient in this case presented with shoulder pain and melena, caused by a gastropericardial fistula that had occurred as a late complication of postoperative esophagogastrostomy and a refractory gastric ulcer. Despite the severity of the condition, the patient showed great improvement after medical treatment and the fistula was cured at the end.


Endoscopy | 2012

A novel disposable, transnasal esophagoscope: a pilot trial of feasibility, safety, and tolerance.

Joo Won Chung; Semi Park; Moon Jae Chung; Jeong Youp Park; Seung Woo Park; Jae Bock Chung; Si Young Song

A novel disposable transnasal esophagoscope, the E.G. Scan (IntroMedic Co. Ltd., Seoul, Korea), was developed for the evaluation of esophageal diseases while eliminating the inconvenience associated with sterilization, portability, patient monitoring, complications, and the economic burden of sedation. The feasibility, safety, and tolerability of the first version of the E.G. Scan was evaluated in this pilot study. Nasal esophagoscopy was performed successfully in 46 patients with known or suspected esophageal diseases. At least 50% of the Z-line was visualized by the E.G. Scan in 38 (82.6%) of 46 patients. Abnormalities were identified in 27 patients: erosive esophagitis (n=18), Barretts esophagus (n=1), esophageal varices (n=7), and esophageal candidiasis (n=1). Nasal pain was absent or mild in most patients, and adverse events were not observed. Further technical improvement of the E.G. Scan would increase the diagnostic usefulness in future clinical practice.


Gut and Liver | 2013

Phase II Trial of Erlotinib Plus Gemcitabine Chemotherapy in Korean Patients with Advanced Pancreatic Cancer and Prognostic Factors for Chemotherapeutic Response

Semi Park; Moon Jae Chung; Jeong Youp Park; Jae Bock Chung; Seungmin Bang; Seung Woo Park; Si Young Song

Background/Aims Erlotinib and gemcitabine combined chemotherapy is becoming the treatment of choice in advanced pancreatic cancer. We evaluated the effectiveness of treatment with erlotinib plus gemcitabine and the prognostic factors for chemotherapeutic response in Korean pancreatic cancer patients. Methods Sixty-nine patients with advanced pancreatic cancer who were treated with daily erlotinib 100 mg orally and gemcitabine 1,000 mg/m2/30 min intravenous infusion on days 1, 8, and 15 of each 4-week cycle from 2006 to 2009 were included in this study. This study was a phase II single-center trial. Results All 69 patients with advanced pancreatic cancer were chemotherapy-naïve. The objective response rate was 18.8%, and the overall tumor-stabilization rate was 49.2%. The median overall survival was 7.7 months (95% confidence interval [CI], 6.0 to 9.4 months). The median progression-free survival was 1.9 months (95% CI, 1.4 to 2.5 months). Prognostic factors for good chemotherapeutic response were good performance status and the presence of skin rash during chemotherapy. Patients with lower performance scores showed worse chemotherapeutic responses (odds ratio [OR], 7.6; 95% CI, 2.4 to 24.8). Poor responses were predicted by the absence of skin rash during chemotherapy (OR, 3.0; 95% CI, 1.4 to 6.3). Conclusions Erlotinib and gemcitabine chemotherapy is a tolerable treatment regimen and has a favorable therapeutic effect in Korean patients with advanced pancreatic cancer.


Yonsei Medical Journal | 2014

The efficacy of endoscopic palliation of obstructive jaundice in hepatocellular carcinoma

Semi Park; Jeong Youp Park; Moon Jae Chung; Jae Bock Chung; Seung Woo Park; Kwang Hyub Han; Si Young Song; Seungmin Bang

Purpose Obstructive jaundice in patients with hepatocellular carcinoma (HCC) is uncommon (0.5-13%). Unlike other causes of obstructive jaundice, the role of endoscopic intervention in obstructive jaundice complicated by HCC has not been clearly defined. The aim of this study was to evaluate the clinical characteristics of obstructive jaundice caused by HCC and predictive factors for successful endoscopic intervention. Materials and Methods From 1999 to 2009, 54 patients with HCC who underwent endoscopic intervention to relieve obstructive jaundice were included. We defined endoscopic intervention as a clinical success when the obstructive jaundice was relieved within 4 weeks. Results Clinical success was achieved in 23 patients (42.6%). Patients in the clinical success group showed better Child-Pugh liver function (C-P grade A or B/C; 17/6 vs. 8/20), lower total bilirubin levels (8.1±5.3 mg/dL vs. 23.1±10.4 mg/dL) prior to the treatment, and no history of alcohol consumption. The only factor predictive of clinical success by multivariate analysis was low total bilirubin level at the time of endoscopic intervention, regardless of history of alcohol consumption [odds ratio 1.223 (95% confidence interval, 1.071-1.396), p=0.003]. The cut-off value of pre-endoscopic treatment total bilirubin level was 12.8 mg/dL for predicting the clinical prognosis. Median survival after endoscopic intervention in the clinical success group was notably longer than that in the clinical failure group (5.6 months vs. 1.5 months, p≤0.001). Conclusion Before endoscopic intervention, liver function, especially total bilirubin level, should be checked to achieve the best clinical outcome. Endoscopic intervention can be helpful to relieve jaundice in well selected patients with HCC.


Gastroenterology | 2010

W1896 Combination Therapy of Gemcitabine and Irinotecan in Advanced Biliary Tract Cancer: Phase II Trial

Moon Jae Chung; Semi Park; Jeong Youp Park; Seungmin Bang; Seung Woo Park; Si Young Song

3, 7 (9.2%): Ki67 negative, 33 (43.4%); positive, 43 (56.6%). The staining intensity of Skp2 and Cks1 showed significant linear correlation (Pearsons R 0.427, p < 0.01). Each staining intensity of Skp2 and Cks1 also showed significant linear correlations with the staining intensity of p27kip1, respectively (Pearsons R 0.314, p < 0.01 for Skp2 and p27kip1, Pearsons R 0.403, p < 0.01 for Cks1 and p27kip1). The positive immunostaining group for Ki67 showed significantly stronger immunostaining intensity for Skp2 (p < 0.01), Cks1 (p < 0.01) and cytoplasmic p27kip1 (p = 0.033). By Kaplan-Meier analyses, the higher IS (p = 0.018) and stronger immunostaining intensity (p < 0.01) of Skp2 and Cks1 were significantly associated with shorter survival for patients with extrahepatic cholangiocarcinoma. Conclusions: Overexpression of Skp2/Cks1 and aberrant localization of p27kip1 into cytoplasm might be useful predictors of prognosis in patients with extrahepatic bile duct cancer.


The Korean Journal of Hepatology | 2004

[The clinical report of 1,078 cases of hepatocellular carcinomas: National Cancer Center experience].

Jae Hee Cheon; Joong Won Park; Kyung Woo Park; Yoon-Goo Kim; Seong-Hoon Kim; Woo Jung Lee; Park Hs; Semi Park; Hong Ek; Chang Min Kim

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Won Ho Kim

Seoul National University Hospital

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