Joon Hyuk Choi

Gangneung-Wonju National University, Gangneung, Gangwon-do, South Korea

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Publications (72)111.35 Total impact

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    Joon Hyuk Choi, Kyung-Tae Kim, Sang Moo Kim
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    ABSTRACT: Squid is one of the most important commercial fishes in the world and is mainly utilized or consumed as sliced raw fish or as processed products. The biofunctional activities of enzymatic squid meat hydrolysate were determined to develop value-added products. Enzymatic squid hydrolysate manufactured by Alcalase effectively quenched 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and hydrogen peroxide radical with IC50 values of 311, 3,410, and 111.5 μg/mL, respectively. Angiotensin I-converting enzyme inhibitory activity of squid hydrolysate was strong with an IC50 value of 145.1 μg/mL, while tyrosinase inhibitory activity with an IC50 value of 4.72 mg/mL was moderately low. Overall, squid meat hydrolysate can be used in food or cosmetic industries as a bioactive ingredient and possibly be used in the manufacture of seasoning, bread, noodle, or cosmetics.
    03/2015; 20(1):67-72. DOI:10.3746/pnf.2015.20.1.67
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    Mi Jin Gu, Joon Hyuk Choi
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    ABSTRACT: Microcystic/reticular schwannoma is a recently described, rare, distinctive histological variant of schwannoma with a predilection for the gastrointestinal tract (GIT). The authors experienced the first case of a microcystic/reticular schwannoma occurring in the esophagus. A 39-year-old male presented for an obstructive sensation during swallowing of several months duration. Endoscopy revealed a bulging mass with intact mucosa at 30 cm from incisors in the esophagus. The mass was excised and gross examination showed it was a well circumscribed, unencapsulated nodule, measuring 3.5×3.2×1.2 cm. On microscopic examination, the tumor showed a vague multinodular appearance with a pushing border and tumor cells arranged in a microcystic and reticular growth pattern with anastomosing and intersecting strands of spindle cells in a myxoid or collagenous/hyalinized stroma. Tumor cells showed diffuse nuclear and cytoplasmic positivity for S100. The authors report the first case of microcystic/reticular schwannoma of the esophagus. Microcystic/reticular schwannoma is a distinctive histological variant of schwannoma with a benign clinical course. However, its histological findings are non-specific and may cause diagnostic difficulties. Awareness of this uncommon neoplasm with distinct histologic features is essential to prevent misdiagnosis.
    BMC Gastroenterology 12/2014; 14(1):193. DOI:10.1186/s12876-014-0193-y · 2.11 Impact Factor
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    ABSTRACT: Background and study aim: Endoscopic ultrasonography-guided transmural gallbladder drainage (EUS-GBD) has been proposed for the management of acute cholecystitis in high risk patients; however, little is known about the long-term outcomes of this treatment. The aim of this study was to evaluate the procedural and long-term outcomes of EUS-GBD with self-expandable metallic stent (SEMS). Patients and methods: Data for this retrospective study were obtained from a prospectively collected EUS database. Patients with acute cholecystitis who were deemed unsuitable for cholecystectomy were included. Study outcomes were technical and clinical success, adverse events, and stent patency. Results: EUS-GBD was technically and clinically successful in 62/63 patients (98.4 %; 95 % confidence interval [CI] 94.9 % - 100 %). Procedural adverse events included duodenal perforation (n = 1, 1.6 %) and self-limiting pneumoperitoneum (n = 2, 3.2 %), all of which resolved with conservative treatment. Long-term outcomes of EUS-GBD were evaluated in 56 patients who were followed for a median of 275 days (range 40 - 1185 days). Late adverse events developed in four patients (7.1 %; 95 %CI 5.7 % - 8.4 %), including asymptomatic distal stent migration (n = 2), and acute cholecystitis due to stent occlusion (n = 2). Two patients with occluded stent were successfully treated endoscopically (reintervention rate of 3.6 %). A total of 54 patients (96.4 %) had no recurrence of acute cholecystitis during follow-up. Median stent patency time was 190 days overall (range 15 - 1185 days) and 458 days (range 151 - 1185 days) for the 28 patients who were alive at the study end. The cumulative stent patency rate was 86 % at 3 years. Conclusions: EUS-GBD with an SEMS for acute cholecystitis showed excellent long-term outcomes and may be a definitive treatment in patients who are unsuitable for cholecystectomy because of advanced malignancy or high surgical risk.
    Endoscopy 06/2014; 46(8). DOI:10.1055/s-0034-1365720 · 5.20 Impact Factor
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    ABSTRACT: To evaluate the success rates, procedural time and adverse event rates of the modified methods in endoscopic ultrasonography-guided hepaticogastrostomy (EUS-HGS). Twenty-eight patients in a prospective case series who underwent EUS-HGS (phase I). Forty-six patients in a matched case-control study (phase II). The simplified technique for fistula dilation was the primary use of a 4 mm balloon catheter with a stainless steel stylet. The stent deployment was modified by deploying the metal stent inside a bile duct (half of the stent) under EUS and fluoroscopic guidance and gently pulling the echoendoscope after full deployment of the stent inside the echoendoscope channel (remaining portion of the stent) under fluoroscopic guidance. This cohort was compared with a matched historical cohort. In phase I, the technical and clinical success with the modified method was 96% (27/28) and 89% (24/27 as per-protocol analysis). The overall adverse event rate was 7%. In phase II, there was no difference in technical and clinical success, stent patency and overall adverse events in each group. However, the procedural time (15.3 ± 5.2 min vs 22.3 ± 6.0 min, P < 0.001) and early adverse events (0% vs 26%, P = 0.02) were statistically improved in case cohort compared with control cohort. Compared with the conventional EUS-HGS technique, the procedural time was shorter and early adverse events were less frequent with our simplified and modified technique.
    World Journal of Gastroenterology 05/2014; 20(17):5051-9. DOI:10.3748/wjg.v20.i17.5051 · 2.43 Impact Factor
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    ABSTRACT: Purpose Kikuchi-Fujimoto disease (KFD) is a benign disease, which is characterized by a cervical lymphadenopathy with fever, and it often mimics malignant lymphoma (ML). 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a powerful imaging modality for the diagnosis, staging and monitoring of ML, with the limitations including the nonspecific FDG uptake in infectious or inflammatory processes. This study compared clinical manifestations and PET/CT findings between KFD and ML patients. Methods We retrospectively reviewed the medical records of 23 patients with KFD and 33 patients with ML, diagnosed histopathologically, between January 2000 and May 2013 at the Department of Pediatrics, Yeungnam University Medical Center. Among them, we analyzed the clinical manifestations, laboratory findings and characteristics, and the amount of 18F-FDG uptake between 8 KFD and 9 ML patients who had 18F-FDG PET/CT. Results The 18F-FDG PET/CT maximum standardized uptake values (SUVmax) ranged from 8.3 to 22.5 (mean, 12.0) in KFDs, and from 5.8 to 34.3 (mean, 15.9) in MLs. There were no significant differences in SUVmax between KFDs and MLs. 18F-FDG PET/CT with ML patients showed hot uptakes in the extranodal organs, such as bone marrow, small bowel, thymus, kidney, orbit and pleura. However, none of the KFD cases showed extranodal uptake (P<0.001). 18F-FDG PET/CT findings of KFD with nodal involvement only were indistinguishable from those of ML. Conclusion Patients who had extranodal involvement on PET/CT were more likely to have malignancy than KFD.
    Korean Journal of Pediatrics 05/2014; 57(5):226-31. DOI:10.3345/kjp.2014.57.5.226
  • Gastrointestinal Endoscopy 05/2014; 79(5):AB215. DOI:10.1016/j.gie.2014.05.065 · 4.90 Impact Factor
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    Jae Beom Hong, Kil-Ho Cho, Joon Hyuk Choi
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    ABSTRACT: Periosteal osteosarcoma is an extremely rare chondroblastic osteosarcoma in the flat bone. There were authors reporting of two cases of periosteal osteosarcoma in the highly unusual sites. One of them arose from the rib, in a 17-year-old male, which appeared as a hypodense juxtacortical mass with periosteal reaction on CT. The other one arose from the scapula, in a 17-year-old female, which showed the intermediate signal intensity (SI) on T1-weighted image (WI), heterogeneous high SI on T2WI, and rim-enhancement on contrast-enhanced T1WI with cortical destruction on MRI.
    Korean journal of radiology: official journal of the Korean Radiological Society 05/2014; 15(3):370-5. DOI:10.3348/kjr.2014.15.3.370 · 1.81 Impact Factor
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    ABSTRACT: Background/Aims: A retrospective analysis was performed to evaluate the safety and effectiveness of extracorporeal shock wave lithotripsy (ESWL) for pancreatolithiasis on successive days under intravenous bolus of pethidine alone. Methods: Ninety patients with calcified pancreatic stones (≥5 mm) presenting with abdominal pain were selected for ESWL. ESWL was performed with an electroconductive lithotripter under fluoroscopic target systems. Fragmented calculi after ESWL were removed by endotherapy. Results: A mean of 4.2 ESWL sessions were performed for each patient, with a mean of 2,984 shocks at a mean power setting of 12.8 kV. Eighty-four (89.3%) patients underwent ESWL for three or more days in a row. Fragmentation of the stones were achieved in 83/90 (92.2%) patients. Complete clearance of the main pancreatic duct was achieved in 54/90 (60.0%) patients, and partial clearance was achieved in 27 (30.0%) patients. The mean dose of pethidine used during ESWL was 53.5±20.7 mg per session. As ESWL-related complications, four (4.3%) patients developed mild acute pancreatitis. Conclusions: In case of endoscopically difficult-to-treat pancreatic duct stones, combined therapy with ESWL is an effective method, and treatment with multiple sessions of ESWL on successive days under intravenous bolus of pethidine alone is safe and well tolerated. (Korean J Gastroenterol 2014;63:231-238).
    The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 04/2014; 63(4):231-8. DOI:10.4166/kjg.2014.63.4.231
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    ABSTRACT: BackgroundsCombined hepatocellular-cholangiocarcinoma (cHC-CC), a malignant liver tumor with poor prognosis, is composed of hepatocellular carcinoma (HCC), cholangiocarcinoma (CC) and diverse components with intermediate features between HCC and CC, which correspond to hepatic progenitor cells.AimsAccording to the WHO classification 2010, we surveyed the prevalence and clinicopathological significance of each subtype with stem cell features (SC subtype; typical subtype [TS], intermediate cell subtype [INT] and cholangiolocellular type [CLC]) in cHC-CC and HCC.Methods Sixty-two patients with cHC-CC (19 women and 43 men) and 26 patients with HCC (all men) were examined. The prevalence of each component was histologically assessed with assistance of mucin and immunohistochemical stainings.ResultsSC subtypes were observed in all cHC-CCs in various amount and combination. The prevalence of each SC subtype in cHC-CC was as follows; TS, 10 (16.1%); INT, 53 (83.9%); and CLC, 44 (71.0%). The proportion of INT was significantly correlated to gender (female-dominant) (p<0.05), tumor size (p<0.05), histological grading of HCC (p<0.01) and inversely correlated to the degree of stromal fibrosis (p<0.05). The proportion of CLC was significantly correlated to the degree of fibrosis (p<0.01) and inflammation (p<0.01), and inversely correlated to tumor size (p<0.01) and histological grading of HCC (p<0.05). The proportion of TS was significantly inversely correlated to the degree of inflammation (p<0.01). Histological diversity score was significantly correlated to vascular invasion and the positivity for α-fetoprotein.Conclusion The proportion of each SC subtype was significantly associated with certain clinicopathological factors, suggesting different properties of each SC subtypes.This article is protected by copyright. All rights reserved.
    Liver international: official journal of the International Association for the Study of the Liver 04/2014; 35(3). DOI:10.1111/liv.12563 · 4.41 Impact Factor
  • Joon Hyuk Choi, Kyung Tae Kim, Sang Moo Kim
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    ABSTRACT: Enzymatic hydrolysis of squid meat was optimized and the biochemical properties of solubility, amino acid composition, and contents of nucleic acid related compounds were determined. Optimal hydrolysis conditions were a pH of 7.0, a hydrolysis time of 5.9 h, a temperature of 55°C, and an enzyme/substrate ratio of 2.4%. More than 75% of squid meat hydrolysate was soluble in a wide pH range. The sweet and savory tasting amino acid contents of the squid hydrolysate were higher than the contents of bitter tasting amino acids. The hydrophilic amino acid content of squid meat was lower than the content of hydrophobic amino acids. The inosine monophosphate content of squid hydrolysate was highest among nucleic acid related compounds. Based on a sensory evaluation, squid complex seasoning was similar or superior to commercial complex seasonings. A squid hydrolysate can be used as an ingredient for manufacture of food products.
    Food science and biotechnology 04/2014; 23(2):417-423. DOI:10.1007/s10068-014-0057-9 · 0.66 Impact Factor
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    ABSTRACT: Background/Aims: Biliary drainage is performed in many patients with cholangiocarcinoma (CCA) to relieve obstructive jaundice. For those who have undergone biliary drainage, bile cytology can be easily performed since the access is already achieved. This study aims to determine the clinical usefulness of bile cytology for the diagnosis of CCA and to evaluate factors affecting its diagnostic yield. Methods: A total of 766 consecutive patients with CCA underwent bile cytology via endoscopic nasobiliary drainage or percuta-neous transhepatic biliary drainage from January 2000 to June 2012. Data were collected by retrospectively reviewing the medical records. We evaluated the diagnostic yield of bile cytology with/without other sampling methods including brush cytology and endobiliary forcep biopsy, and the optimal number of repeated bile sampling. Several factors affecting diagnostic yield were then analyzed. Results: The sensitivity of bile cytology, endobiliary forceps biopsy, and a combination of both sampling methods were 24.7% (189/766), 74.4% (259/348), and 77.9% (271/348), respectively. The cumulative positive rate of bile sampling increased from 40.7% (77/189) at first sampling to 93.1% (176/189) at third sampling. On multivariate analysis, factors associated with positive bile cytology were perihilar tumor location, intraductal growing tumor type, tumor extent ≥20 mm, poorly differ-entiated grade tumor, and three or more samplings. Conclusions: Although bile cytology itself has a low sensitivity in diagnosing CCA, it has an additive role when combined with endobiliary forceps biopsy. Due to the relative ease and low cost, bile cytology can be considered a reasonable complementary diagnostic tool for diagnosing CCA. (Korean J Gastroenterol 2014;63:107-113).
    The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 02/2014; 63(2):107-13. DOI:10.4166/kjg.2014.63.2.107
  • Endoscopy 01/2014; 46(S 01):E441-E442. DOI:10.1055/s-0034-1377501 · 5.20 Impact Factor
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    ABSTRACT: Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a rare disease characterized by increased serum levels of IgG4 and dense infiltration of IgG4-positive plasma cells with fibrosis in the bile duct wall. IgG4-SC is frequently associated with autoimmune pancreatitis (AIP) and typically shows an excellent response to steroid therapy. Despite recent progress in understanding the clinical presentation of IgG4-SC, its diagnosis still remains a challenge, particularly if it manifests as an isolated hilar stricture with normal serum IgG4 concentrations. In this article, we report the case of a 75-year-old man with IgG4-SC in whom it was difficult to distinguish hilar cholangiocarcinoma due to the normal serum IgG4 concentration and no accompanying AIP. He had an indolent clinical course and showed slow progression of a bile duct lesion over 6 years.
    01/2014; 87(2):182. DOI:10.3904/kjm.2014.87.2.182
  • O Hyun Kwon, Kil Ho Cho, Jang Ho Suh, Joon Hyuk Choi
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    ABSTRACT: Nodular fasciitis, a benign soft tissue tumor consisting of myofibroblastic proliferation, is commonly located in the subcutaneous or inter- or intra-muscular layer of extremites. Intra-articular nodular fasciitis is extremely rare. We report a case of MRI findings of a nodular fasciitis in the knee of a 13-year-old boy which was removed by arthroscopic surgery and pathologically confirmed.
    01/2014; 71(5):254. DOI:10.3348/jksr.2014.71.5.254
  • Joon Hyuk Choi, Jae Hwang Kim, Jae Chun Chang
    Pathology 01/2014; 46:S49. DOI:10.1097/01.PAT.0000454267.69246.83 · 2.62 Impact Factor
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    ABSTRACT: Acinic cell carcinoma (ACC) is an uncommon malignant tumor of the salivary glands that is difficult to diagnose. It grows slowly and shows distant metastasis rarely. We experienced a case of recurrent ACC in the parotid gland with cardiac metastasis and hypertrophic osteoarthropathy. The 29-year-old man had been suffering from severe multiple bones and joints pain for 2 months. Ten years earlier, he underwent superficial parotidectomy due to a right subauricular mass. The mass was diagnosed with ACC. After surgery, the tumor recurred twice. Then the patient was diagnosed with cardiac metastasis via positron emission tomography-computed tomography and trans-thoracic echocardiography. He also had hypertrophic osteoarthropathy with multiple bone metastasis. He was given palliative radiotherapy and conservative treatment. ACC in the parotid gland with cardiac metastasis and hypertrophic osteoarthropathy has not yet been reported in literature. From this case, it is recommended to evaluate multiple distant metastasis in the ACC of the parotid gland when joint and bone pain are present.
    01/2014; 31(1):33. DOI:10.12701/yujm.2014.31.1.33
  • 01/2014; 19(3):137-141. DOI:10.15279/kpba.2014.19.3.137
  • Mi Jin Gu, Joon Hyuk Choi
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    ABSTRACT: The aim of this study was to evaluate the epithelial-mesenchymal transition (EMT) and to assess its prognostic significance in intrahepatic cholangiocarcinoma. We performed immunohistochemical stainings for E-cadherin, β-catenin, vimentin and fibronectin in a total of 85 cases. Expression of vimentin and reduced expression of E-cadherin were found to show correlation with poor differentiation (p=0.017, p=0.010). Reduced expression of β-catenin showed significant association with poor differentiation (p=0.023), tumour size (p=0.028) and lymph node metastasis (p=0.011). According to the expression pattern of E-cadherin, β-catenin, vimentin and fibronectin we categorised four phenotypes: complete type, hybrid type, null type and wild type. The complete type of β-catenin with vimentin or fibronectin was found to show an association with lymph node metastasis (p=0.048, p=0.012). Significantly worse overall survival (OS) and disease-free survival (DFS) was observed for the complete type, and the best OS and DFS were observed for the wild type. EMT phenotypes can be useful markers for prediction of patient outcomes.
    Journal of clinical pathology 09/2013; 67(3). DOI:10.1136/jclinpath-2013-201806 · 2.55 Impact Factor
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    Joon Hyuk Choi, Sung Koo Lee
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    ABSTRACT: Percutaneous transhepatic cholangioscopy (PTCS) is the most widely used modality for diagnosis and treatment of biliary disease. Although many other novel technologies have been developed based on recent advances in endoscopy, PTCS has its own role. In diagnostics, PTCS is used for evaluation of indeterminate biliary strictures, bile duct tumors, and postoperative biliary strictures that cannot be reached by a peroral approach. In therapeutics, the removal of bile duct stones, dilatation of bile duct strictures including postoperative anastomosis site strictures, and local tumor therapy are indications of PTCS. Especially in a therapeutic role, PTCS has the advantage of maneuverability due to a shorter endoscopic length compared to other cholangioscopic modalities. Hence, PTCS has its own indispensable diagnostic and therapeutic roles.
    09/2013; 46(5):529-536. DOI:10.5946/ce.2013.46.5.529
  • Mi-Jin Gu, Young-Kyung Bae, Joon Hyuk Choi
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    ABSTRACT: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract and are mostly driven by KIT and PDGFRA-activation mutations. However, other signaling pathways are involved in pathogenesis and proliferation of GISTs. This study investigates the prognostic significance of insulin-like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) and the role of succinate dehydrogenase subunit B (SDHB) in GISTs. Immunohistochemistry (IHC) for IGF1, IGF1R and SDHB was performed in total of 165 GISTs. The overexpression of IGF1 was evident in tumors with high mitotic count, large tumor size and was correlated with high risk of malignant behavior. IGF1R overexpression was correlated with IGF overexpression, high mitotic count and high risk of malignant behavior. Loss of expression for SDHB was found in only 2 gastric GISTs. The overexpression of IGF1 and IGF1R can be useful marker to predict relapse and aggressive behavior in GISTs and has prognostic implications.
    Hepato-gastroenterology 09/2013; 60(126):1383-6. DOI:10.5754/hge13102 · 0.91 Impact Factor

Publication Stats

291 Citations
111.35 Total Impact Points

Institutions

  • 2014–2015
    • Gangneung-Wonju National University
      • Department of Marine Food Science and Technology
      Gangneung, Gangwon-do, South Korea
    • Asan Medical Center
      • Department of Gastroenterology
      Sŏul, Seoul, South Korea
  • 2013–2014
    • University of Ulsan
      • Department of Internal Medicine
      Urusan, Ulsan, South Korea
  • 2002–2014
    • Yeungnam University
      • • Department of Pathology
      • • Division of Internal Medicine
      • • Department of Neurosurgery
      • • College of Medicine
      Daikyū, Daegu, South Korea
  • 2009–2013
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2010
    • Sungkyunkwan University
      • Samsung Medical Center
      Sŏul, Seoul, South Korea
    • Inje University
      • College of Medicine
      Kimhae, South Gyeongsang, South Korea