Young-Eun Joo

Prevalence and risk factors of Helicobacter pylori infection in Korea: Nationwide multicenter study over 13 years

BackgroundThe aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors.MethodsThis cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated.ResultsAfter exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area.ConclusionsA decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.

Cyclooxygenase-2 overexpression correlates with vascular endothelial growth factor expression and tumor angiogenesis in gastric cancer

Angiogenesis is a key prerequisite for the successful establishment, growth, and dissemination of tumors. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity and cyclooxygenase-2 (COX-2) promotes angiogenesis by modulated production of angiogenic factors including VEGF. The current study was designed to investigate the possible roles of COX-2 and VEGF in gastric cancer angiogenesis. In this study, we conducted an immunohistochemical investigation of COX-2 and VEGF expression in 97 patients with gastric cancer. To assess tumor angiogenesis, microvessel density (MVD) was determined by CD34 immunohistochemical staining. Expression of COX-2 and VEGF in gastric cancer tissues, was demonstrated in 63.9% and 75.3% of cases, respectively. The expression of COX-2 correlated significantly with VEGF expression. High MVD was significantly associated with depth of tumor invasion and poor survival. The mean MVD value of VEGF positive tumors was 79.8 ± 32.0 and significantly higher than that of VEGF negative tumors. The mean MVD value of COX-2 positive tumors was 77.9 ± 29.9 and not significantly higher than that of COX-2 negative tumor. The mean value of MVD in tumors positive for both COX-2 and VEGF was significantly higher than that in tumors negative for both. However, there was no correlation between COX-2 or VEGF expression and various clinicopathological features including patient survival. These results suggest that COX-2 may play an important role in carcinogenesis by stimulating tumor angiogenesis in concert with VEGF in human gastric cancer.

Expression of E-Cadherin, Alpha- and Beta-Catenins in Patients with Pancreatic Adenocarcinoma

Background/Aims: E-Cadherin and its associated cytoplasmic proteins, catenins, are important mediators of epithelial cell–cell adhesion and intracellular signaling. Much evidence exists suggesting a tumor invasion suppressor role for E-cadherin and catenins and loss of expression, as well as mutations, has been described in a number of epithelial cancers. The aim of this study was to evaluate the expression of E-cadherin and catenins in pancreatic adenocarcinoma tissue, and to examine the relationship between these expression and various clinicopathological parameters. Methods: In this study, we conducted an immunohistochemical investigation of expression of E-cadherin, α- and β-catenins in 30 tissue samples obtained from pancreatic ductal adenocarcinoma patients undergoing surgical treatment. Results: In the pancreatic mucosa of noncancerous areas, epithelial cells showed equally strong membranous expression of E-cadherin, α- and β-catenin proteins at the cell–cell boundaries. Reduced expression of E-cadherin, α- and β-catenins was demonstrated in 60.0, 40.0, and 56.7% of cancer tissues, respectively. Reduced expression of E-cadherin, α- and β-catenins correlated with tumor dedifferentiation (p = 0.012, 0.013, and 0.033, respectively). Reduced expression of E-cadherin correlated with stage and lymph node involvement (p = 0.031, 0.009, respectively). α-Catenin and β-catenin expression did not correlate with the patient’s age and sex, with the tumor size, location, stage and depth of invasion, or lymph node involvement and distant metastasis. Conclusion: These results suggest that the E-cadherin and catenins may be a useful marker of differentiation and prognosis in pancreatic adenocarcinoma, although the mechanisms underlying changes in E-cadherin and catenin expression are not fully known.

Antibiotic Prophylaxis Using Third Generation Cephalosporins Can Reduce the Risk of Early Rebleeding in the First Acute Gastroesophageal Variceal Hemorrhage: A Prospective Randomized Study

Bacterial infection may be a critical trigger for variceal bleeding. Antibiotic prophylaxis can prevent rebleeding in patients with acute gastroesophageal variceal bleeding (GEVB). The aim of the study was to compare prophylactic third generation cephalosporins with on-demand antibiotics for the prevention of gastroesophageal variceal rebleeding. In a prospective trial, patients with the first acute GEVB were randomly assigned to receive prophylactic antibiotics (intravenous cefotaxime 2 g q 8 hr for 7 days, prophylactic antibiotics group) or to receive the same antibiotics only when infection became evident (on-demand group). Sixty-two patients in the prophylactic group and 58 patients in the on-demand group were included for analysis. Antibiotic prophylaxis decreased infection (3.2% vs. 15.5%, p=0.026). The actuarial rebleeding rate in the prophylactic group was significantly lower than that in the ondemand group (33.9% vs. 62.1%, p=0.004). The difference of rebleeding rate was mostly due to early rebleeding within 6 weeks (4.8% vs. 20.7%, p=0.012). On multivariate analysis, antibiotic prophylaxis (relative hazard: 0.248, 95% confidence interval (CI): 0.067-0.919, p=0.037) and bacterial infection (relative hazard: 3.901, 95% CI: 1.053-14.448, p=0.042) were two independent determinants of early rebleeding. In conclusion, antibiotic prophylaxis using third generation cephalosporins can prevent bacterial infection and early rebleeding in patients with the first acute GEVB.

A prospective, randomized trial of endoscopic band ligation vs. epinephrine injection for actively bleeding Mallory-Weiss syndrome.

BACKGROUND Effective hemostatic treatment is mandatory for patients with actively bleeding Mallory-Weiss syndrome. This study evaluated the respective efficacy and the safety of endoscopic band ligation and endoscopic epinephrine injection in Mallory-Weiss syndrome. METHODS Thirty-four consecutive patients with actively bleeding Mallory-Weiss syndrome were prospectively enrolled and were randomly assigned to undergo endoscopic band ligation or endoscopic injections of a 1:10,000 solution of epinephrine. Demographic characteristics, endoscopic variables, and outcome parameters, including rates of hemostasis and recurrent bleeding, were analyzed. RESULTS The number of elastic bands applied was one or two; the mean volume of epinephrine injected was 18.0 mL: 95% CI[16.8, 19.2]. There was no significant difference between the groups with respect to age, gender, alcohol ingestion, presenting symptoms, Hb level, shock, comorbid diseases, coagulopathy, tear location, blood transfusion, or duration of hospitalization. Primary hemostasis was achieved in all 17 patients in the band ligation group and in 16 of 17 patients (94.1%) in the epinephrine injection group. There was no recurrence of bleeding or major complication in either group. CONCLUSIONS In this small study, no difference was detected in the efficacy or the safety of band ligation vs. epinephrine injection for the treatment of actively bleeding Mallory-Weiss syndrome.

A prospective, randomized trial comparing mechanical methods of hemostasis plus epinephrine injection to epinephrine injection alone for bleeding peptic ulcer

BACKGROUND The hemostatic efficacy of mechanical methods of hemostasis, together with epinephrine injection, was compared with that of epinephrine injection alone in bleeding peptic ulcer. METHODS Ninety patients with a peptic ulcer with active bleeding or a non-bleeding visible vessel were randomly assigned to undergo a mechanical method of hemostasis (23 hemoclip application, 22 band ligation) plus epinephrine injection, or epinephrine injection alone. RESULTS The two groups were similar with respect to all background variables. Initial hemostasis was achieved in 44/45 (97.8%) patients in both groups. The mean number of hemoclips and elastic bands applied were 2.8: 95% CI[2.5, 3.1] and 1.1: 95% CI[1.0, 1.2], respectively, and the mean volume of epinephrine injected was 19.9 mL: 95% CI[19.3 mL, 20.5 mL]. The rate of recurrent bleeding in the combination group (2/44, 4.5%) was significantly lower in comparison with the injection group (9/44, 20.5%, p < 0.05). The mean number of therapeutic endoscopic sessions needed to achieve permanent hemostasis in the combination group (1.04: 95% CI[1.01, 1.07]) was significantly lower vs. the injection group (1.22: 95% CI[1.15, 1.30]). CONCLUSIONS The combination of an endoscopic mechanical method of hemostasis plus epinephrine injection is more effective than epinephrine injection alone for the treatment of bleeding peptic ulcer.

Optimal injection volume of epinephrine for endoscopic prevention of recurrent peptic ulcer bleeding

BACKGROUND Although the initial rate of hemostasis achieved by endoscopic epinephrine injection for peptic ulcer bleeding is high, bleeding recurs in 14.6% to 35.5% of patients. The aim of this study was to compare rates of recurrent bleeding after endoscopic injection of two different volumes of epinephrine in patients with peptic ulcer bleeding. METHODS A total of 72 patients with peptic ulcer with active bleeding or a non-bleeding visible vessel were randomly assigned to 15 to 25 mL or 35 to 45 mL injections of a 1:10,000 solution of epinephrine. RESULTS The two groups were similar with respect to all background variables. The mean volume of epinephrine injected was 19.4 mL: 95% CI [18.7, 20.1] in the 15 to 25 mL group and 41.1 mL: 95% CI [40.0, 42.2] in the 35 to 45 mL group. Initial hemostasis was achieved in 35 of 36 patients (97.2%) in the 15 to 25 mL group and in all 36 patients in the 35 to 45 mL group. The 35 to 45 mL volume was significantly more effective in preventing recurrent bleeding than the 15 to 25 mL volume (0% vs. 17.1%; p < 0.05). For ulcers in the gastric body, the 35 to 45 mL volume was significantly more effective in preventing recurrent bleeding than the 15 to 25 mL volume (0% vs. 31.6%; p = 0.003). For ulcers in other locations, including the gastric antrum and the duodenum, there were no significant differences in the rate of recurrent bleeding between the two groups. CONCLUSIONS Injection of 35 to 45 mL of a 1:10,000 solution of epinephrine is more effective than injection of 15 to 25 mL of the same solution for prevention of recurrent bleeding from ulcers in the body of the stomach.

Expression of cyclooxygenase-2 protein in colorectal carcinomas.

SummaryBackground. Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various human cancers, including colorectal cancer. Thus, overexpression of COX-2 may be involved in the growth and progression of cancer, and this may have prognostic significance.Aim. The aim of our study is to evaluate the expression of COX-2 in colorectal cancer tissue, and to examine the relationship of its expression to various clinicopathological parameters and patient survival.Methods. Formalin-fixed, paraffin-embedded tissue blocks were obtained from 60 patients who underwent surgery for colorectal carcinoma in 1995 at the Chonnam National University Hospital in Gwangju, Korea. We have used an immunohistochemical technique to localize COX-2 in colorectal carcinoma tissues.Results. Immunohistochemical staining of the colorectal cancer specimens demonstrated that COX-2 expression was localized to the carcinoma cells and was not detectable in the stromal compartment of the cancers. The COX-2 immunostaining pattern was predominantly homogenous, and perinuclear cytoplasmic within the tumors. Normal colonic epithelium adjacent to the tumor showed no staining for COX-2. The COX-2 protein was detected in 70% (42/60) of colorectal carcinoma tissues. However, no significant correlation was found between COX-2 expression and various clinicopathological parameters, including histologic grade, tumor size, depth of invasion, lymph node metastasis, distant metastasis, or stage. Furthermore, COX-2 expression did not correlate with patient survival (p=0.401).Conclusion. These results suggest that COX-2 expression may play an important role in the evolution of colon carcinogenesis. However, further studies are needed to determine the prognostic relevance of COX-2.

Cyclooxygenase-2 Expression Is Associated with Well-Differentiated and Intestinal-Type Pathways in Gastric Carcinogenesis

Background/Aims: Cyclooxygenase-2 (COX-2) expression appears to be increased in several different types of human cancers, suggesting that the presence of COX-2 is associated with carcinogenesis. Recently, increased expression of COX-2 has been frequently detected in gastric cancer, and this may have prognostic significance. In the present study, we aimed to analyze the expression of COX-2 in a much larger sample to determine whether COX-2 expression is related to the clinicopathological features and survival rates of patients with gastric cancer. Methods: We investigated 140 patients with gastric cancer who underwent surgery between January 1992 and December 1993 and examined the expression of COX-2 in human gastric cancer tissue by immunohistochemistry. Results: COX-2 expression was present in the cytoplasm of tumor cells but not in normal gastric epithelia. Positive expression of COX-2 was detected in 86 of 140 gastric cancers analyzed (61.4%). Positive expression of COX-2 correlated with the depth of tumor invasion (p = 0.015). However, there was no association between COX-2 expression and tumor stage or status of lymph node or distant metastasis. Furthermore, COX-2 expression was not associated with patient survival (p = 0.816). Positive expression of COX-2 occurred more frequently in intestinal than in diffuse or mixed types of cancer and correlated with tumor differentiation (p < 0.001, p = 0.001, respectively). Conclusion: These results suggest that COX-2 may play an important role in the evolution of gastric carcinogenesis and be associated with well-differentiated and intestinal type pathways in gastric carcinogenesis. However, COX-2 expression seems to be less useful for establishing prognosis for gastric cancer.

Clinical outcomes and risk factors of post-polypectomy coagulation syndrome: A multicenter, retrospective, case-control study

BACKGROUND AND STUDY AIMS Post-polypectomy coagulation syndrome (PPCS) is a well known complication of colonoscopic polypectomy. However, no previous studies have reported on the clinical outcomes or risk factors of PPCS. The aim of the current study was to analyze the clinical outcomes and risk factors of PPCS developing after a colonoscopic polypectomy. PATIENTS AND METHODS Data for all patients who underwent colonoscopic polypectomies and required hospitalization in nine university hospitals were analyzed retrospectively. The incidence, clinicopathological characteristics, and clinical outcomes of PPCS cases were examined. Additionally, patients who developed PPCS were compared with controls who were matched by age and sex, in order to assess for possible risk factors. RESULTS The rate of PPCS that required hospitalization after colonoscopic polypectomy was 0.7/1000. All patients with PPCS were treated medically without the need for surgical interventions. The median durations of therapeutic fasting, hospitalization, and antibiotic use were 3 days, 5.5 days, and 7 days, respectively. The rates of major PPCS and mortality were 2.9 % and 0 %, respectively. On multivariate analysis, hypertension (OR = 3.023, 95 %CI 1.034 - 8.832), large lesion size (OR = 2.855, 95 %CI 1.027 - 7.937), and non-polypoid configuration (OR = 3.332, 95 %CI 1.029 - 10.791) were found to be independent risk factors related to the development of PPCS. CONCLUSIONS In this study, the rates of major PPCS and mortality were only 2.9 % and 0 %, respectively. Hypertension, large lesion size, and non-polypoid configuration of the lesion were independently associated with PPCS. Therefore, patients may be reassured by the excellent prognosis of PPCS, while endoscopists should be especially careful when performing colonoscopic polypectomies in patients with hypertension or large and non-polypoid lesions.