Y C Lee

Yonsei University Hospital, Seoul, Seoul, South Korea

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Publications (13)32.76 Total impact

  • Article: Histologic diagnosis based on forceps biopsy is not adequate for determining endoscopic treatment of gastric adenomatous lesions.
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    ABSTRACT: Controversy persists around the treatment of gastric low-grade dysplasia (LGD). The aim of this study was to investigate possible indications for the endoscopic resection of gastric LGD through analysis of the histologic discrepancies between specimens of gastric LGD obtained by forceps biopsy and by endoscopic mucosal resection (EMR), and of their clinicopathologic characteristics. The study involved 293 gastric LGD that were histologically proven on the basis of forceps biopsy in Severance Hospital between January 2004 and December 2007. Twenty cases were regularly followed up, and the remaining 273 were resected by EMR. We performed univariate and multivariate analyses of clinical and endoscopic characteristics including lesion size, number of biopsy fragments, and endoscopic appearance, in order to analyze the factors affecting histologic discrepancies. Of the 273 lesions resected by EMR, 207 (75.8 %) showed concordant histology, whereas for 51 (18.7 %) the histology was upgraded after endoscopic resection. Lesion size, absence of whitish discoloration, and the presence of spontaneous bleeding were found by univariate analysis to be statistically significant factors predicting an upgraded histology after EMR ( P = 0.026, P < 0.001, and P = 0.025, respectively). Multivariate analysis also showed absence of whitish discoloration to be a statistically significant factor influencing histologic discrepancies ( P = 0.001, odds ratio 5.29, 95 % confidence interval 1.95 - 14.37). Perforation and bleeding rates associated with EMR for LGD were 0.7 % and 6.2 %, respectively. Twenty patients who did not undergo EMR were followed up for a mean of 22 months, and 3 were revealed to have adenocarcinoma and 1 high-grade dysplasia on the latest histologic exam. We should consider endoscopic resection for gastric LGD that are 2 cm or more in size and do not have whitish discoloration.
    Endoscopy 08/2010; 42(8):620-6. · 5.21 Impact Factor
  • Article: Long-term clinical outcomes of self-expanding metal stents for treatment of malignant gastroesophageal junction obstructions and prognostic factors for stent patency: effects of anticancer treatments.
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    ABSTRACT: Self-expanding metal stent has emerged as an effective treatment option for malignant gastroesophageal junction obstruction. However, data on the clinicopathologic factors associated with stent patency are still lacking. To investigate the long-term clinical outcomes and prognostic factors, including treatment modalities, affecting stent patency in patients with malignant gastroesophageal junction obstruction given self-expanding metal stent insertions. A total 89 patients who underwent self-expanding metal stent insertion for malignant gastroesophageal junction obstruction were enrolled. We analysed technical and clinical success rates, complications, and prognostic factors affecting stent patency. Self-expanding metal stent insertion was successful in all patients and clinical improvement was achieved in 93.3%. Stent malfunction occurred in 32.9% of patients. The median overall survival time and stent patency time were 143 (95% CI: 99-187) and 190 days (95% CI: 108-272), respectively. In multivariate analysis, radiation therapy after stent placement significantly prolonged stent patency (OR: 0.221; 95% CI: 0.055-0.884; p=0.033). A higher migration rate was observed in those patients given chemotherapy after covered self-expanding metal stent placement (no anticancer treatment: 10.0%, chemotherapy: 42.9%, chemoradiation therapy: 9.1%, p=0.042). Self-expanding metal stent is a feasible and effective treatment for malignant gastroesophageal junction obstruction. Radiation therapy after stent placement significantly prolongs overall stent patency and chemotherapy increases the migration rate of covered stents.
    Digestive and Liver Disease 09/2009; 42(6):436-40. · 3.05 Impact Factor
  • Article: Treatment outcomes of 70 cases of early esophageal carcinoma: 12 years of experience.
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    ABSTRACT: Early esophageal cancer (EEC) has an excellent prognosis compared to advanced esophageal cancer. Nowadays, endoscopic mucosal resection (EMR) may offer another alternative to cure early cancers of the gastrointestinal tract. We aimed to evaluate the clinical outcomes of EEC in Korea after curative treatments; EMR or surgery. We retrospectively reviewed the medical records of patients diagnosed as EEC from January 1994 to August 2005 at Yonsei University Medical Center, Seoul, Korea. Among 888 patients diagnosed with esophageal cancer, 70 (7.9%) were included as EEC. Among them, 10 patients (14.3%) were treated by EMR, and 50 (71.4%) by operation. The treatment outcomes of EEC in relation to various clinicopathologic factors along with survival rates were analyzed. There were 18 cases (30%) of mucosal lesions and 42 cases (70%) of submucosal lesions. Overall 5-year survival rate was 84.3%. When comparing treatment outcomes between EMR-treated and operated groups, there were no significant differences in complete remission (80%vs. 84%), recurrence (20%vs. 16%) and 5-year survival rate (100%vs. 78.3%). EEC is a potentially curable entity with a good clinical prognosis. EMR can be considered as another treatment arm for EEC, along with surgical resection.
    Diseases of the Esophagus 02/2007; 20(4):297-300. · 1.81 Impact Factor
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    Article: Helicobacter pylori infection in Korea.
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    ABSTRACT: Helicobacter pylori is a gram-negative bacterium that was first isolated in 1982. Since then, H. pylori infection in humans has been shown to be associated with gastritis, peptic ulcer disease, gastric carcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma as well. The epidemiology, transmission, and pathogenicity of H. pylori has been a subject of intensive study. Successful treatment improves the cure rate of peptic ulcerations and treatment with antimicrobials also decreases the recurrence rate of these diseases. Better regimens having less toxicity and a good eradication rate have also been developed. A better understanding of the pathophysiologic mechanisms relating to H. pylori induced mucosal damages would result in more options for the prevention of peptic ulcers and carcinogenesis. Korea has a relatively high incidence of H. pylori infection and gastric cancer. Growing interest has developed in view of its importance in being associated with various gastroduodenal diseases. Furthermore, along with a high incidence of H. pylori-related disease in Korea, because the interaction between H. pylori, host factors and environmental factors is important in disease pathogenesis, we need to have precise data on the characteristics of H. pylori-related diseases that occur in Korea. In the present report we review the epidemiology, transmission route, diagnosis, pathogenesis, treatment methods and relationship with gastroduodenal diseases with in special references to basic and clinical data that have been published.
    Yonsei Medical Journal 09/2001; 42(4):457-70. · 1.14 Impact Factor
  • Article: Effects of nonsteroidal anti-inflammatory drugs on Helicobacter pylori-infected gastric mucosae of mice: apoptosis, cell proliferation, and inflammatory activity.
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    ABSTRACT: Helicobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) are two well-known important causative factors of gastric damage. While H. pylori increases apoptosis and the proliferation of gastric epithelial cells and is an important factor in peptic ulcer and gastric cancer, NSAIDs induce cell apoptosis and have antineoplastic effects. We investigated the effects of NSAIDs (a nonselective cyclooxygenase [COX] inhibitor [indomethacin] and a selective COX-2 inhibitor [NS-398]) on the apoptosis and proliferation of gastric epithelial cells and gastric inflammation in H. pylori-infected mice. C57BL/6 mice were sacrificed 8 weeks after H. pylori SS1 inoculation. Indomethacin (2 mg/kg) or NS-398 (10 mg/kg) was administered subcutaneously once daily for 10 days before sacrifice. The following were assessed: gastric inflammatory activity, gastric COX protein expression by Western blotting; gastric prostaglandin E(2) levels by enzyme immunoassay, apoptosis by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, and cell proliferation by Ki67 immunostaining. Compared to the controls, H. pylori infection and/or NSAID treatment increased COX-1 and COX-2 protein expression. Gastric prostaglandin E(2) levels, apoptotic index, cell proliferation index, neutrophil activity, and the degree of chronic inflammation were all increased by H. pylori infection, and these effects were significantly decreased by indomethacin treatment. However, NS-398 treatment after H. pylori infection did not induce a significant reduction, although it did result in a tendency to decrease. These results show that NSAIDs can reverse the increased apoptosis and proliferation of epithelial cells and inflammatory activity in the stomachs of H. pylori-infected mice and that, like COX-2 activation, COX-1 induction contributes to the change of gastric mucosal cell turnover and inflammation induced by H. pylori infection.
    Infection and Immunity 09/2001; 69(8):5056-63. · 4.16 Impact Factor
  • Article: A case of Cronkhite-Canada syndrome involving the entire gastrointestinal tract.
    Endoscopy 04/2001; 33(4):385. · 5.21 Impact Factor
  • Article: Follicular dendritic cell sarcoma presenting as a submucosal tumor of the stomach.
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    ABSTRACT: Follicular dendritic cell (FDC) sarcomas, especially those of extranodal origin, are extremely rare, and this entity could easily be missed without a high index of suspicion. We report a case of FDC sarcoma presenting as a submucosal tumor of the stomach in a 45-year-old man. The mass was a spindle and epithelioid mesenchymal tumor with many individually scattered and perivascular aggregates of lymphocytes. Immunohistochemical and ultrastructural studies confirmed the diagnosis. Although more than 50 cases of this tumor have been documented in the English literature, to our knowledge the presentation of FDC sarcoma as a submucosal tumor of the stomach has never been recorded. This case highlights the occurrence of FDC sarcoma as a submucosal tumor of the gastrointestinal tract. We believe that FDC sarcoma should be included in the differential diagnosis of spindle or epithelioid cell tumors of the gastrointestinal hollow viscus to prevent this still under-recognized tumor from being overlooked.
    Archives of pathology & laboratory medicine 12/2000; 124(11):1693-6. · 2.58 Impact Factor
  • Article: The Effect of Si3N4 Additions on the Oxidation Resistance of TiAl Alloys
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    ABSTRACT: The oxidation kinetics of TiAl alloys with and without 3 and 5 wt.%additions of Si3N4 particles were studied at 1173 and1273 K in 1 atm of air. The Si3N4 dispersions wereunstable in the matrix phase, so that some of them reacted with titaniumduring sintering to form Ti5Si3 and dissolvednitrogen. The oxide scale formed on TiAl–Si3N4alloys consisted of an outer TiO2, an intermediate(Al2O3+TiO2), and an inner(TiO2+Al2O3) mixed layers. The enhancedalumina-forming tendency, the presence of discrete SiO2 particlesbelow the outer TiO2 layer, and the improved scale adhesion bySi3N4 dispersions were attributable mainly to theincreased oxidation resistance compared to the Si3N4-freeTiAl alloys. Marker experiments showed that, for TiAl–Si3N4 alloys, the primary mode of scale growth was the outward diffusion oftitanium ions for the outer scale and the inward transport of oxygen ionsfor the inner scale.
    Oxidation of Metals 11/2000; 54(5):575-589. · 1.40 Impact Factor
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    Article: Clinicopathologic characteristics of early gastric cancer in Korea.
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    ABSTRACT: Gastric cancer is the most common cause of cancer related death in Korea. Early gastric cancer (EGC), confined to mucosa or submucosa, regardless of lymph node metastasis, is known to have a favorable prognosis. From 1976 to 1995, four thousand nine hundred and twenty eight gastric cancer patients underwent operation at the Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea. Of these, 1,117 patients (22.6%) were diagnosed as EGC and underwent curative operation. Clinicopathologic characteristics were reviewed and survival data was analyzed. The proportion of EGC has increased during the last two decades, from 14.9% during 1976-1985 to 25.8% for 1986-1995. EGC has a wide age distribution range from the thirties to the sixties, with highest incidence in the sixties. The male to female ratio is 1.8:1, without any significant change in last two decades. Most lesions are located in the lower third of stomach (52.3%), and the lesser curvature (52.2%) was the most frequent site in the transverse axis. Macroscopically, the depressed type was the most common (66.1%) followed by the elevated, flat and mixed types, in that order. Tumor confined to the mucosa layer was seen in 52.5%, and lymph node involvement in 11.7%. The depth of tumor invasion correlated with tumor size and regional lymph node involvement. On histopathologic examination, signet ring cell type accounted for 29.6% of all EGCs. Overall 5-year survival rate was 92.7% and the presence of lymph node metastasis significantly affected survival (84.6% versus 96.2%) (p<0.05). In conclusion, the proportion of EGC, in terms of the gastric cancers operated upon, has been increasing in Korea over the last two decades. The introduction of active diagnostic approaches and diagnostic modalities could improve early diagnosis and the cure rate of gastric cancer in Korea.
    Yonsei Medical Journal 10/2000; 41(5):607-14. · 1.14 Impact Factor
  • Article: Accumulated frameshift mutations at coding nucleotide repeats during the progression of gastric carcinoma with microsatellite instability.
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    ABSTRACT: Microsatellite instability (MSI) and frameshift mutations in genes containing nucleotide repeats have been reported in a subset of gastric carcinomas, but the mutational profiles in precancerous lesions have not been characterized. To characterize the genetic events during gastric carcinogenesis, we analyzed DNA from 56 gastric adenomas and 167 gastric carcinomas for MSI using five microsatellite markers and for frameshift mutations at coding nucleotide repeats of the type II transforming growth factor beta receptor, BAX, hMSH3, hMSH6, IGF II receptor, and E2F-4 genes. On the basis of the number of markers displaying instability per tumor, the tumors were divided into three groups: those with two or more of the five markers showing instability (high MSI [MSI-H]), those with one of the five markers showing instability (low MSI [MSI-L]), and those with no instability. MSI-H was found in 8 adenomas (14%) and 19 carcinomas (11%), and MSI-L was found in 8 adenomas (14%) and 9 carcinomas (5%). These groups were tested for correlations with several clinicopathologic parameters. MSI-H gastric adenomas were related to the high histologic grade of composing dysplastic glands (p = 0.004), and MSI-H gastric carcinomas were associated with exophytic tumor growth (p = 0.005). We found 48 frameshift mutations at coding nucleotide repeats of the six genes, and all mutations except one were found in MSI-H gastric tumors. Only one of the 17 MSI-L tumors showed frameshift mutations at coding nucleotide repeats of the transforming growth factor beta receptor II gene. Compared with MSI-H gastric carcinomas, MSI-H adenomas had no mutations in the hMSH6 and the IGF II receptor genes, less frequent mutations in the transforming growth factor beta receptor II (38% versus 63%), BAX (13% versus 37%), and hMSH3 (13% versus 37%) genes, and more frequent mutations in the E2F-4 (50% versus 37%) gene. Our findings suggest that MSI and E2F-4 mutations are early genetic events and that mutations of the other five genes are accumulated during the progression of gastric carcinomas with MSI.
    Laboratory Investigation 10/1999; 79(9):1113-20. · 3.64 Impact Factor
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    Article: P53 overexpression in gastric adenocarcinoma with Helicobacter pylori infection.
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    ABSTRACT: Gastric carcinogenesis has been studied in various aspects. Helicobacter pylori (Hp) infection and mutation of the p53 tumor suppressor gene have recently been argued to be important factors of gastric carcinogenesis. There have been many studies to determine the precise mechanism of how Hp is related to gastric cancer, but it is so far still unknown. We studied the relationship of Hp infection and p53 overexpression and tried to discover some significance in clinicopathologic factors such as age, sex, stage, site, differentiation and gross morphology. Ninety-six patients who were diagnosed with gastric cancer at Severance Hospital, Yonsei University Medical College from November 1995 to March 1996, and 96 control patients of non-ulcer dyspepsia (NUD) were studied by endoscopic biopsy of normal gastric tissue and cancer tissue. They also underwent the CLO (Delta West, Melbourne, Western Australia) test for Hp positivity and p53 immunohistochemical stain for p53 positivity. These data were analyzed for comparison with the clinicopathologic characteristics of gastric cancers. In conclusion, the differentiated group cancer had a significantly high Hp positivity and p53 positivity. There is a possibility that Hp infection and p53 tumor suppressor gene mutation might be significantly related in the gastric carcinogenic process of well- and moderately-differentiated adenocarcinomas, but further study is necessary to determine more direct clues on the carcinogenic roles of these factors.
    Yonsei Medical Journal 05/1997; 38(2):117-24. · 1.14 Impact Factor
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    Article: Evaluation of therapeutic regimens for the treatment of Helicobacter pylori infection.
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    ABSTRACT: Helicobacter pylori (H. pylori) is currently considered the most important exogenous factor in the genesis of gastritis and peptic ulcer disease. However, the optimum regimen for the eradication of H. pylori remains unclear. The purpose of this study was to evaluate the eradication rate of H. pylori, the side effects, and the patients' compliance with regard to various drug regimens. We also analyzed factors influencing the eradication of H. pylori. One hundred and eighty patients were included and divided into four groups: 42 patients (Group I) received tripotassium dicitrato bismuthate (240 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; 55 patients (Group 2) received omeprazole (20 mg b.i.d.) and amoxicillin (1000 mg b.i.d.) for 14 days; 36 patients (Group 3) were treated with omeprazole (20 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; and 47 patients (Group 4) received omeprazole (20 mg q.d.) and amoxicillin (500 mg t.i.d.) for 14 days and then tripotassium dicitrato bismuthate (240 mg b.i.d.) and nizatidine (150 mg q.d.) for 14 days. The diagnosis of H. pylori was made by histology. The eradication of H. pylori was defined both by histology (H&E and Giemsa stain) and by rapid urease test (CLOR) showing negative for H. pylori 4 weeks after the completion of therapy. Of the 180 patients, 95 patients had non-ulcer dyspepsia, 40 patients had gastric ulcer and 45 patients had duodenal ulcer. The eradication rate of H. pylori was highest (89.3%) in Group 3, as compared with Group 1 (68.9%), Group 2 (65.4%), and Group 4 (48.9%). The eradication rate was significantly higher in Group 3 than in Groups 2 and 4 (p < 0.05). There was no significant difference in the eradication rate among clinical diagnosis, sex and age. But, in the conventional triple therapy (Group 1), the eradication rate was higher in male (78.6%) than in female (46.2%). The side effects in order, were nausea (22.1%), dizziness (19.5%), abdominal pain (11.6%) and diarrhea (97%), and there was no difference among the drug regimens. The compliance of the patients was good (more than 80% irrespective of drug regimen). On the basis of these findings, the side effects of the drugs seemed minimal, and the compliance of patients was good irrespective of the drug regimen. In conclusion, the triple therapy with omeprazole, metronidazole and amoxicillin was the most effective regimen and could be recommended for H. pylori eradication.
    Yonsei Medical Journal 08/1996; 37(4):270-7. · 1.14 Impact Factor
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    Article: p53 protein expression in extrahepatic bile duct cancer.
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    ABSTRACT: p53 mutations, a tumor suppressor gene located on chromosome 17p, are the most common genetic alterations found in human cancers. Although the p53 expression or mutation has been investigated in a variety of cancers there have been very few studies in extrahepatic bile duct cancers. In this study, we investigated the immunohistochemical expression of p53 in formalin fixed paraffin embedded archival specimens of 36 extrahepatic bile duct cancers in which p53 expression was found in eighteen (50%) cases. There was no significant difference in age, gender, size of tumor, histologic grade, extent of tumor involvement, lymph node metastasis and tumor resectability according to p53 immunoreactivity. Comparison of survival duration according to p53 expression showed no significant difference. In conclusion, we reported 50 percent of p53 expression in extrahepatic bile duct cancers by immunohistochemical staining and we found no prognostic significance of p53 expression in dinicopathologic parameters.
    Yonsei Medical Journal 05/1996; 37(2):112-7. · 1.14 Impact Factor