Kwang Ro Joo

Kyung Hee University Medical Center, Sŏul, Seoul, South Korea

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Publications (78)126.07 Total impact

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    ABSTRACT: Although current guideline recommends selective use of pre-endoscopic prokinetics to increase diagnostic yield in upper gastrointestinal bleeding (UGIB) patients, no data to guide the use of these drugs are available.
    Digestive Diseases and Sciences 10/2014; · 2.26 Impact Factor
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    ABSTRACT: To develop and validate a risk stratification-based screening model for predicting colorectal advanced neoplasia in Korea. Colorectal advanced neoplasia is the relevant finding of screening colonoscopy. Risk estimation for advanced neoplasia may be helpful to improve compliance and to develop more cost-effective approaches toward screening. We developed Korean Colorectal Screening (KCS) score by optimizing and adjusting Asia-Pacific Colorectal Screening (APCS) score to predict advanced neoplasia in an asymptomatic Korean population who received screening colonoscopies from September 2006 to September 2009. Moreover, we validated the KCS score in another Korean cohort who received screening colonoscopies from October 2009 to February 2011. We also assessed the predictive power and diagnostic performance of both KCS and APCS scores. There were 3561 subjects in the derivation cohort and 1316 subjects in the validation cohort, with a prevalence of advanced neoplasia of 4.7% and 4.3%, respectively. After a multivariate analysis, KCS was developed as 0 to 8 points comprising of age, sex, body mass index, smoking, and family history of CRC. Using KCS scores to stratify the validation cohort, the prevalences of advanced neoplasia in the 3 risk tiers (average, moderate, and high) were 2.0%, 3.7%, and 10.9%, respectively. Moderate-risk and high-risk tiers showed 2.1- and 6.5-fold increased prevalences, respectively, of advanced neoplasia compared with average risk tier. In addition, KCS score showed relatively good discriminative power (ROC=0.681) and higher sensitivity compared with APCS score for the high-risk tier. KCS score may be clinically simple and useful for assessing advanced neoplasia risk in Korea. However, racial disparity should be considered in risk stratification-based screening in each country.
    Journal of clinical gastroenterology 02/2014; · 2.21 Impact Factor
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    ABSTRACT: Untreated benign biliary stricture can lead to serious complications including recurrent cholangitis, biliary cirrhosis, hepatic failure, and death. Benign stricture of a postoperative anastomosis site is also a problematic issue after biliary surgery. Percutaneous transhepatic cholangioscopy (PTCS) with balloon dilatation is a recently introduced noninvasive therapeutic option for biliary stricture. Guidewire insertion through the stricture site is essential for the success of PTCS treatment. Recently, we treated a difficult case with complete bilioenteric anastomosis stricture that failed to allow passage of the guidewire for balloon dilation. The stricture was treated with artificial bilioenteric fistula using a needle-knife papillotome during the PTCS.
    Surgical laparoscopy, endoscopy & percutaneous techniques 02/2014; 24(1):e10-2. · 0.88 Impact Factor
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    ABSTRACT: To identify the predicting factors of present hepatitis C virus (HCV) infection among patients with positivity for antibodies to HCV (anti-HCV). We analyzed patients who showed positive enzyme immunoassay (EIA) results and performed an HCV RNA test as a confirmatory test at Kyung Hee University Hospital at Gangdong from June 2006 to July 2012. The features distinguishing the groups with positive and negative HCV RNA results were reviewed. In total, 490 patients were included. The results of the HCV RNA test were positive and negative in 228 and 262 patients, respectively. The index value of anti-HCV, mean age, platelet counts, total bilirubin, prothrombin time international normalized ratio, albumin and alanine transaminase (ALT) levels differed significantly between the two groups. On multivariable analysis, an index value of anti-HCV >10 [odds ratio (OR)=397.27, P<0.001), ALT >40 IU/L (OR=3.64, P=0.001), and albumin <3.8 g/dL (OR=2.66, P=0.014) were related to present HCV infection. Although EIA is not a quantitative test, considering the anti-HCV titer with ALT and albumin levels may be helpful in predicting present of HCV infection.
    Clinical and molecular hepatology. 12/2013; 19(4):376-81.
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    ABSTRACT: We investigated the prognostic role of F-FDG PET/CT in the prediction of progression-free survival (PFS) and chemotherapeutic response in patients with locally advanced or metastatic pancreatic cancer. We enrolled 21 newly diagnosed patients with locally advanced or metastatic pancreatic cancer who underwent F-FDG PET/CT scanning before palliative gemcitabine-based chemotherapy between 2006 and 2012. Maximum standardized uptake value (SUVmax) of the primary tumor was measured by F-FDG PET/CT. Chemotherapeutic response was evaluated according to the Response Evaluation Criteria in Solid Tumors. Survival analysis was performed for time to progression using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent prognostic factors. All pancreatic tumors showed detectable FDG uptake (mean SUVmax = 6.8 ± 3.0, range 2-12) The mean SUVmax values among response groups showed no significant difference (P = 0.853) and chemotherapeutic response was not different according to SUVmax level (P = 0.807). PFS was significantly shorter in the high SUVmax (≥6.8) group than in the low SUVmax (<6.8) group (2.9 vs. 6 months, P = 0.012). Multivariate analysis revealed that SUVmax was an independent prognostic factor for predicting PFS (P = 0.046). Higher SUVmax of primary pancreatic tumor is associated with poor PFS and pretreatment SUVmax is an independent prognostic factor for predicting PFS in patients with locally advanced or metastatic pancreatic cancer who received gemcitabine-based palliative chemotherapy. However, pretreatment SUVmax is not associated with chemotherapeutic response.
    Clinical nuclear medicine 10/2013; 38(10):778-783. · 3.92 Impact Factor
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    ABSTRACT: To investigate whether patients with obstructive sleep apnea (OSA) are at risk of sedation-related complications during diagnostic esophagogastroduodenoscopy (EGD). A prospective study was performed in consecutive patients with OSA, who were confirmed with full-night polysomnography between July 2010 and April 2011. The occurrence of cardiopulmonary complications related to sedation during diagnostic EGD was compared between OSA and control groups. During the study period, 31 patients with OSA and 65 controls were enrolled. Compared with the control group, a higher dosage of midazolam was administered (P = 0.000) and a higher proportion of deep sedation was performed (P = 0.024) in the OSA group. However, all adverse events, including sedation failure, paradoxical responses, snoring or apnea, hypoxia, hypotension, oxygen or flumazenil administration, and other adverse events were not different between the two groups (all P > 0.1). Patients with OSA were not predisposed to hypoxia with multivariate logistic regression analysis (P = 0.068). In patients with OSA, this limited sized study did not disclose an increased risk of cardiopulmonary complications during diagnostic EGD under sedation.
    World Journal of Gastroenterology 08/2013; 19(29):4745-51. · 2.55 Impact Factor
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    ABSTRACT: The advantage of the quantitative fecal immunochemical test (FIT) is the flexibility to set the positivity threshold. However, the diagnostic success of the FIT has not been compared for standard and low cut-off thresholds. The purpose of this study was to compare the diagnostic success of FIT for standard and low cut-off thresholds. In 2009 and 2010 a standard cut-off threshold (20 μg Hb/g feces) was used as positivity criterion for the FIT; in 2012 a low cut-off (10 μg Hb/g feces) was used. Diagnostic success was compared between the two groups. Of the total of 14,289 participants, 195 (1.4 %) had positive FIT results. Positivity of the FIT was significantly higher in the low cut-off group than in the standard cut-off group (1.8 vs. 1.0 %, p = 0.000). Although detection of advanced neoplasia lesions was comparable, proximal neoplasia was more frequently detected in the low cut-off group (33.3 vs. 20.9 %, p = 0.016). With the low cut-off threshold, 39 (0.7 %) participants were also classified as having positive results, and 18 (46.2 %) of these had colorectal neoplasias. The number of positive results from the FIT was increased by 54.9 %, and detection of advanced neoplasia was increased by 60 % with the low cut-off threshold compared with the standard cut-off. A low cut-off threshold for the FIT resulted in better detection of proximal neoplasia in population-based screening. These results indicate the cut-off threshold for positive FIT should be properly chosen and adjusted in colorectal cancer screening.
    Digestive Diseases and Sciences 08/2013; · 2.26 Impact Factor
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    ABSTRACT: Increasing evidence supports the contribution of the pro-/anti-inflammatory cytokine balance and genetic factors to hepatocellular carcinoma (HCC). Here, we investigated whether genetic interferon gamma polymorphisms were associated with HCC in Korean patients with chronic hepatitis B. We genotyped a single nucleotide polymorphism (SNP, rs2430561, +874A/T) and a microsatellite (rs3138557, (CA) (n) repeat), located in the first intron of the interferon gamma gene, by direct sequencing and the gene scan method. A population-based case-control study of HCC was conducted and included 170 patients with chronic hepatitis and HCC, and 171 with chronic hepatitis B patients without hepatocellular carcinoma in a Korean population. Genotype and allele distributions of the interferon gamma gene SNP were associated with HCC. The frequencies of the AA genotype and the A allele were significantly increased in hepatocellular carcinoma subjects (p < 0.05). Combined analysis using the genotype of rs2430561 and the number of microsatellites revealed that the frequencies of AT-CA12, and TT-CA12 increased significantly in hepatocellular carcinoma subjects (p < 0.0001). Our results suggest that the interferon gamma gene may be a susceptibility gene and a risk factor for HCC in the Korean population.
    Hepato-gastroenterology 06/2013; 60(128):2080-4. · 0.77 Impact Factor
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    ABSTRACT: Background/Aims: The aim of this study was to determine whether the major HLA-G gene was associated with hepatocellular carcinoma (HCC). Abnormal HLA-G expression is present in various diseases, such as renal cell carcinoma, asthma and classical Hodgkin's lymphoma. Methodology: To investigate the possible association with susceptibility to HCC, 181 chronic hepatitis patients and 180 HCC patients were enrolled in this study. The HLA-G 14-bp insertion/deletion polymorphism is located in the 3' untranslated region of the HLA-G gene and was analyzed using polymerase chain reaction. For analysis of genetic data, SNPStats and SPSS 18.0 were used. Logistic regression models were performed to determine the odds ratio, 95% confidence interval, and p value. Results: Allele and genotype frequencies of the HLA-G 14-bp insertion/deletion polymorphism in the hepatitis group had a similar pattern, as compared to those in the HCC group. Furthermore, no differences were observed between patients with and without liver cirrhosis. Conclusions: These results suggest that the HLA-G 14-bp insertion/deletion polymorphism may not be associated with HCC susceptibility and liver cirrhosis development in the Korean population.
    Hepato-gastroenterology 06/2013; 60(124):796-8. · 0.77 Impact Factor
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    ABSTRACT: BACKGROUND: Type 2 diabetes mellitus is associated with an increased risk of colorectal neoplasia. However, association between prediabetes and colorectal adenoma has not been reported. AIMS: The aim of this study was to evaluate the relationship between prediabetes and the presence of colorectal adenomas. METHODS: Consecutive prediabetic subjects who underwent screening colonoscopy were enrolled at Kyung Hee University Hospital in Gangdong, Seoul, Korea, between June 2006 and May 2012. Non-prediabetic subjects were separately pooled from the database of the Center for Health Promotion between January 2012 and May 2012. Prediabetes was defined according to the recommendations of the American Diabetes Association. The prevalence of colorectal adenomas and their characteristics were compared between prediabetic and non-prediabetic groups. RESULTS: The prevalence of colorectal adenoma was higher in prediabetic subjects than in non-prediabetic subjects (39.6 vs. 30.6 %, respectively, p = 0.019). Prediabetic subjects had more multiple and high-risk adenomas than the control group in non-matched analysis (p = 0.000, respectively). In age-matched analysis, the prevalence of multiple and high-risk adenomas were significantly higher in a prediabetic group than those in a control group (44.4 vs. 28.4 %, p = 0.034; 51.9 vs. 34.6 %, p = 0.026, respectively). Furthermore, prediabetes (odds ratio = 2.198; 95 % confidence interval = 1.042-4.637; p = 0.039) was found to be an independent risk factor for a high-risk adenoma by multivariate analysis. CONCLUSIONS: The prevalence of multiple and high-risk colorectal adenomas is significantly higher in the prediabetic subjects than those in the control group. Furthermore, prediabetes was found to be an independent risk factor for a high-risk colorectal adenoma.
    Digestive Diseases and Sciences 02/2013; · 2.26 Impact Factor
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    ABSTRACT: : Recently, it was reported that postmenopausal women with lower bone mineral density have an increased risk of colorectal cancer. An association between lower bone mineral density and colorectal cancer suggests that colorectal adenoma, which is a precursor of colorectal cancer, may also be associated with lower bone mineral density. : The aim of this study was to determine the association between colorectal adenoma and osteoporosis. : We conducted a retrospective cross-sectional study between January 2007 and May 2011. Women older than 50 years of age who underwent dual-energy x-ray absorptiometry for bone mineral density and screening colonoscopy at Gangdong Kyung Hee University Hospital in Korea during a routine health checkup were eligible for this study. We performed multivariate analysis adjusted for age, family history of colorectal cancer, alcohol consumption, current smoking, regular aspirin use, exercise, menopause, and postmenopausal hormone use to identify independent predictors for the presence of colorectal adenoma. : The primary outcome measured was the prevalence of colorectal adenoma according to the bone mineral density level. : A total of 992 women older than 50 years were assigned to an osteoporosis group (n = 231) or a control group (n = 231) after menopause matching. In univariate analysis, the proportion of colorectal adenoma was significantly higher in the osteoporosis group than in the control group (29.9% vs 20.8%, p = 0.025). Furthermore, osteoporosis (OR = 1.592, 95% CI = 1.004-2.524, p = 0.048) was found to be an independent risk factor for the presence of colorectal adenoma. : Osteoporosis is associated with an increased risk of colorectal adenoma in women older than 50 years.
    Diseases of the Colon & Rectum 02/2013; 56(2):169-74. · 3.34 Impact Factor
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    ABSTRACT: Development of biliary casts is very unusual, especially in patients who have not undergone liver transplantation. Variable causes of biliary cast formation in nonliver transplantation patients have been suggested. However, stasis of bile flow and/or gallbladder hypocontractility is known to eventually result in the promotion of biliary sludge and subsequent cast formation. Here we present one case of biliary cast syndrome, which developed in a nonliver transplant patient who had biliary sludge for a long period of time, providing evidence that long-standing biliary sludge may lead to cast formation.
    Clinical endoscopy. 01/2013; 46(1):98-101.
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    ABSTRACT: Synovial sarcoma is a rare type of soft tissue sarcoma that arises in tissues containing synovial fluid, usually in the extremities. It has only rare occurrence in the retroperitoneal space. Early detection of retroperitoneal synovial sarcoma is difficult, since the retroperitoneal space is highly expandable and deeply hidden. Furthermore, the presenting symptoms are often vague and nonspecific, and are related to the pressure on adjacent structures. In this study, we present an unusual case of retroperitoneal synovial sarcoma with obstructive jaundice due to intrabiliary blood clots caused by invasion of bile duct by tumor. The obstructive jaundice was relieved through endoscopic removal of the blood clots and insertion of a biliary stent.
    Clinical endoscopy. 11/2012; 45(4):428-30.
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    ABSTRACT: Background/Aims: Fecal immunochemical test (FIT) is an integral component of most colorectal cancer (CRC) screening programs. However, little is known about clinical risk factors associated with advanced colorectal neoplasia (CRN) despite negative FIT results. The aim of this study was to determine the clinical predictors of advanced CRN despite negative FIT results. Methods: We performed FITs for asymptomatic subjects ≥50 years from January 2009 to December 2010. Patients who underwent colonoscopy for a medical check-up, despite a negative FIT result, were included to evaluate the clinical predictors of advanced CRN based on colonoscopy. Results: During the study period, 373 subjects underwent screening colonoscopy despite their negative FIT results. Among those 373 subjects, 356 (95.4%) did not show any advanced CRNs; however, 17 (4.6%) subjects showed advanced CRNs on their colonoscopies despite negative FIT results. Being a first-degree relative of a CRC patient was significantly associated with advanced CRNs in univariate analysis (p = 0.031). According to multivariate logistic regression analysis, being a first-degree relative of a CRC patient was a significant predictor of advanced CRNs despite negative FIT results (OR 7.33; 95% CI, 0.53-35.08; p = 0.013). Conclusion: First-degree relatives of CRC patients are likely to show advanced CRNs despite a negative FIT.
    Digestion 10/2012; 86(4):283-287. · 1.94 Impact Factor
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    ABSTRACT: Colonoscopists are often hesitant to perform endoscopic polypectomy in patients with liver cirrhosis (LC) because of the risk for postpolypectomy bleeding (PPB). However, little is known about the risk of PPB in these patients. We performed a retrospective study of patients with early LC who underwent colonoscopic polypectomy at a single center between September 2006 and May 2011. We investigated the incidence of immediate PPB (IPPB) and delayed PPB (DPPB) in these patients. In addition, we investigated which LC-related and polyp-related factors were associated with IPPB. Thirty patients with LC were included in our study, and 29 (96.7 %) of them were classified in Child-Pugh class A or B. The mean prothrombin time was 1.27 ± 0.23, and the mean platelet count was 136.77 ± 106.49 × 10(3)/L. A total of 66 polyps in 30 patients were removed. In terms of IPPB, only 2 (3.03 %) of the 66 removed polyps presented with mild oozing and were controlled by hemostatic procedures using hemoclips. DPPB did not occur in any of the patients in the IPPB or the non-IPPB group. Although the IPPB polyp group was too small to detect statistical significance, the IPPB polyps were larger than the non-IPPB polyps (22.5 ± 10.61 vs. 7.22 ± 3.01 mm), and the gross morphology of both IPPB polyps was the pedunculated type. However, LC-related variables such as platelet counts and Child-Pugh scores did not significantly differ between the IPPB and non-IPPB groups. In patients with early LC, the risk of postpolypectomy bleeding was acceptably low and there was no case with DPPB. Therefore, polypectomy can be performed with caution. IPPB was associated with the size and the gross morphology of the polyps. However, LC-related variables in patients with early LC did not impact IPPB.
    Surgical Endoscopy 05/2012; 26(11):3258-63. · 3.43 Impact Factor
  • Endoscopy 04/2012; 44 Suppl 2 UCTN:E32-3. · 5.74 Impact Factor
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    ABSTRACT: Hemoglobin concentration of fecal immunochemical test may be decreased at high ambient temperature, and fecal samples in FIT may be exposed to high ambient temperature. The aim of this study was to determine whether a high ambient temperature on the day of screening may decrease the performance of FITs in population-based screening. We performed FITs for asymptomatic participants aged 50 years or older. Fecal hemoglobin concentration, the probability of a positive FIT and a detection rate of colorectal neoplasms were compared between low (<10.0 °C) and high (≥25.0 °C) temperature groups. The FIT results for 8,316 participants were analyzed. The mean log(10) Hb concentration in the low temperature group was significantly higher than those in the high temperature group (0.36 vs. 0.25 ng/ml, p = 0.000). Regression analysis showed that an increase in temperature of 1 °C reduced the probability of a positive FIT by 3.1 %. However, we found no differences between the two groups in the FIT positive rate and detection rate of colorectal neoplasms. In multivariate analysis, high ambient temperature was not a significant risk factor for either the positive FIT result or the detection of colorectal neoplasms. Potential instability of fecal hemoglobin at high ambient temperatures should be considered; however, its influence on performance of FIT may be attenuated by the short exposure time of fecal samples to high ambient temperature (i.e., rapid return system).
    Digestive Diseases and Sciences 03/2012; 57(8):2178-83. · 2.26 Impact Factor
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    ABSTRACT: The present study was aimed at evaluating the usefulness of box simulators for training novice endoscopists. An explanation of the goals, contents, and features of the simulator was given to study participants. The participants then received "hands-on training" in gastrointestinal endoscopy techniques using a box simulator. Subsequently, they were asked to answer 19 structured questions about the simulator. Ratings were scored on a scale from 1 to 5 for questions concerning their first impression of the simulator. Questions on the usefulness of the simulator and the training course were answered as "agree", "disagree", or "no opinion". A total of 32 participants filled out the questionnaire. The mean scores on the simulator's usefulness, features, and realistic movements before the training were between 1.5 and 2.0. There were no significant differences between the mean values of the scores given by novice users compared to non-novice users. However, after receiving training on the simulator, 90.6% of the participants considered the box simulator a generally useful tool for learning basic endoscopic techniques, and 90.6% agreed that the simulator was useful for improving hand-eye coordination. Box simulators may be useful for training novice endoscopists in basic gastrointestinal endoscopic techniques.
    Yonsei medical journal 03/2012; 53(2):304-9. · 0.77 Impact Factor
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    ABSTRACT: Difficult cannulation is a well known risk for post-ERCP pancreatitis. This study evaluated the outcomes of needle-knife fistulotomy (NKF) used prior to being faced with difficult biliary cannulation. Patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) for the purpose of biliary endotherapy between January 2007 and December 2008 were eligible for this study; 218 patients were recruited. Biliary cannulation was performed only by a standard catheter or a pull type papillotome, without wire-guided assistance in all patients. If selective cannulation was not achieved within five cannulation attempts, NKF was performed, and the results were compared with the easy cannulation group that succeeded biliary cannulation within five attempts. Needle-knife fistulotomy (NKF) was performed in 72 (33.0%) of the 218 patients. The total success rate of the ERCP was 98.2% (214/218), and for the NKF group the success rate was 94.4% (68/72). The rate of complications in patients with NKF did not increase compared to patients in the easy cannulation group (P > 0.05): 4.2% (3/72) versus 3.4% (5/146) for acute pancreatitis, 6.9% (5/72) versus 6.8% (10/146) for bleeding, and 1.4% (1/72) versus 0% (0/146) for perforation, respectively. Our results suggest that the use of NKF for biliary cannulation might be safe and effective. Therefore, in experienced hands, early use of NKF might be recommended.
    Digestive Diseases and Sciences 01/2012; 57(5):1384-90. · 2.26 Impact Factor
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    ABSTRACT: We present photochemical-induced pancreatic necrosis (PIPN) as a novel induction method for studying pancreatic regeneration in an animal model. Photosensitive Rose Bengal was injected through the femoral vein in rats, followed by illumination of the surface of the pancreas with a cool halogen light for a period of 20 min. At 3, 6, and 24 h, and 7, 10, 14, and 20 days, experimental animals were sacrificed; all the animals received intravenous injection with 5-bromo-2-deoxyuridine (BrdU) 1 h prior to sacrifice. At 3-6 h of induction of PIPN, pancreatic necrosis was superficially observed in the illuminated field. At 24 h, there was a slight increase in the depth and width of the lesion along with appearance of vascular congestion and thrombosis in the lesion. On days 7-10, the area of illumination was totally replaced by necrotic pancreatic tissue, inflammatory cell infiltrates, and newly appearing cellular components, including mesenchymal and epithelial cells, which formed tubular complexes. On day 14, clusters of tubular complexes intermingled with acinar cells, which were proven as newly formed acinar tissue by BrdU staining. On day 20, all the lesions had returned to a normal state of pancreatic tissue. This study demonstrates the potential of PIPN as a valuable method for production of an animal model for studying healing processes or regeneration of pancreatic tissue after injury.
    Pancreatology 01/2012; 12(1):74-8. · 2.04 Impact Factor

Publication Stats

176 Citations
126.07 Total Impact Points

Institutions

  • 2004–2013
    • Kyung Hee University Medical Center
      • Department of Laboratory Medicine
      Sŏul, Seoul, South Korea
  • 2007–2009
    • Kyung Hee University
      • College of Medicine
      Seoul, Seoul, South Korea
  • 2003
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea