[The role of gastric acid in the H. pylori-induced gastritis in mouse].

BACKGROUND/AIMS: This study was designed to investigate the role of gastric acid in the extent of H. pylori-induced gastritis. METHODS: Twenty eight mice were inoculated with live H. pylori. They were allocated into four groups. Mice in group I received no treatment, group II mice were treated with sham injection, group III received 125 microg/kg body weight of pentagastrin, while group IV received 250 microg/kg body weight of pentagastrin subcutaneously three times a week. After 7 months, the mucosal pH, H. pylori density, neutrophils and monocytes infiltration, and the degree of atrophy were assessed in the stomach. RESULTS: In the gastric body, the densities of H. pylori were not different among groups. The degree of neutrophil infiltration was significantly lower in group IV compared to other groups (p<0.05). The degree of monocyte infiltration was also significantly lower in group IV than group III (p<0.05). In the gastric antrum, there was no significant difference of the H. pylori density, neutrophil and monocyte infiltration, and degree of atrophy among the groups. The mice with the gastric mucosal pH lower than mean of 3.2 had significant lower level of H. pylori density (1.4 vs. 2.4, p=0.04), and infiltration of neutrophils (0.9 vs. 2.3, p=0.018), and monocytes (1.2 vs. 1.8; p=0.011) than the those with mucosal pH above 3.2 in the body of stomach. CONCLUSIONS: Gastric acid plays a role in suppressing the proximal propagation of H. pylori-induced gastritis to the body of stomach.

[Expression of CD40 in gastric cancer and its effect on the apoptosis of gastric cancer cells].

BACKGROUND/AIMS: The expression of CD40 in gastric cancer has not been studied. The aims of this study were to determine the expression of CD40 in gastric cancer and to investigate the effect of CD40 on the apoptosis of gastric cancer cells. METHODS: We examined the expression of CD40 by immunohistochemistry and flow cytometry. CD40 mRNA in 5 gastric cancer cell lines was analyzed by RT-PCR. To assess the effect of CD40 on the viability of gastric cancer cells, we performed MTT assay. The effect of CD40 signaling on the apoptosis of gastric cancer cells was examined by annexin V affinity assay. RESULTS: Twelve of twenty human gastric cancer tissues demonstrated positive staining for CD40. Among 5 gastric cancer cell lines, AGS cell line expressed membrane-bound CD40 antigen and CD40 mRNA. In AGS cells, CD40 stimulation significantly reduced the cell viability. CD40 ligation significantly increased the apoptosis in AGS cells compared to the control. CONCLUSIONS: CD40 is expressed in human gastric cancer tissues and gastric cancer cell line, and induces apoptosis in gastric cancer cells. These results suggest that CD40 expression in gastric cancer may play an important role in host defense mechanism against the gastric cancer.

[Effect of Helicobacter pylori on gastric epithelial cell kinetics and expression of apoptosis-related proteins in gastric carcinogenesis].

BACKGROUND/AIMS: We investigated apoptosis, cell proliferation and the expression of apoptosis-related proteins in the gastric epithelial cells of Helicobacter pylori (H. pylori)-negative and positive patients. METHODS: TUNEL staining, immunohistochemical staining for Ki-67, p53, Bcl-2, Bcl-X(L) and Bax were performed on paraffin-embedded specimens obtained from 11 H. pylori-negative controls, 20 H. pylori-positive chronic gastritis, 10 chronic gastritis with intestinal metaplasia (IM), 11 adenoma, and 7 adenocarcinoma patients. Apoptosis and proliferation were expressed as apoptosis index (AI) and proliferation index (PI). RESULTS: In H. pylori-positive groups, apoptosis and proliferation were increased compared with controls. However, an AI/PI ratio was highest in chronic gastritis cases and then gradually reduced according to the progress from IM to cancer. p53 was expressed in 28.6% of adenocarcinoma cases. Expression of Bax was significantly increased in chronic gastritis and IM patients compared with controls. CONCLUSIONS: H. pylori infection induces marked increase in apoptosis and proliferation of gastric mucosa. In the premalignant lesions, the balance between apoptosis and proliferation is altered, and this imbalance may play a key role in the gastric carcinogenesis.

[Expression patterns of E-cadherin and beta-catenin according to clinicopathological characteristics of hepatocellular carcinoma].

BACKGROUND/AIMS: E-cadherin is involved in intercellular binding and cellular polarity formation. beta-catenin plays a fundamental role in regulation of the E-cadherin cell adhesion complex. The abnormalities of the components of the complex may disrupt this adhesive function. We investigated the expression patterns of E-cadherin and beta-catenin to determine the clinical significance of these proteins in hepatocellular carcinoma. MATERIALS/METHODS: Thirty-six hepaticellular carcinoma tissues and adjacent non-tumor specimens were analyzed. Subcellular distribution of E-cadherin and beta-catenin was examined by immunohistochemistry staining. We evaluated the patterns of the expression, and investigated the relationship with the cause of HCC; level of AFP; TNM stage; tumor size; growth types; metastasis; differentiation grade of HCC; and presence of portal vein thrombosis. RESULTS: Immunohistochemistry showed that all non-tumor tissues had membranous type staining of E-cadherin. All non-tumor tissues showed cytoplasmic type staining of beta-catenin, but no beta-catenin accumulation in nuclei was found. 58% (21/36) of HCC showed positive expression of E-cadherin in cytoplasmic membrane. The cytoplasmic expression of beta-catenin in HCC was 83% (30/36); nuclear expression in 14% (5/36); and no staining in 3% (1/36). Nuclear beta-catenin expression was observed in none (0/4) of the well-differentiated HCC; 17%(3/9) of moderate-differentiated HCC; and 17%(2/6) of poorly-differentiated HCC. There were no relationships between E-cadherin and beta-catenin expression with other clinicopathologic factors. CONCLUSIONS: Loss of cytoplasmic staining of E-cadherin and nuclear accumulation of beta-catenin were observed in HCC. Nuclear accumulation of beta-catenin was not found in well differentiated HCC but was found in poorly differentiated HCC.

[Efficacy and safety of long-term lamivudine therapy in the patients with decompensated liver cirrhosis secondary to hepatitis B].

BACKGROUND/AIMS: Lamivudine use in patients with decompensated cirrhosis B has been reported to improve the hepatic function and often delay the need for liver transplantation. In the present study, we evaluated the efficacy and safety of long-term lamivudine therapy in patients with decompensated cirrhosis by comparative study using a matched, untreated cohort. METHODS: 41 patients with decompensated cirrhosis B were included for this study (31 male and 10 female; mean age, 50 years; mean observation period, 18 months). They were divided into two groups: a lamivudine treatment group and an untreated control group. 21 patients in the treatment group were treated with lamivudine 75 or 150 mg daily for at least 12 months. Biochemical and serologic markers were evaluated at two to three-month intervals for all patients. Clinical improvement was defined by a decrease in the Child-Pugh score of at least 2 points. RESULTS: During the observation period, 62% (13/21) was responders, 33% (7/21) was breakthrough, and 5% (1/21) was non-responder in the treated group. The mean Child-Pugh score was significantly improved from 8.6 to 6.0 in the treatment group, but aggravated from 8.7 to 10.0 in the control group during the follow-up. The HBeAg seroconversion rate was 31% in the treatment group (5/16) and none in the control group (0/14). Clinical improvement was observed in fifteen of 21 in the treatment group (71%) and only one of 20 in the control group (5%). According to the treatment responses, clinical improvement was observed in ten of 13 responders (77%), four of 7 breakthrough (57%), and one non-responder. CONCLUSIONS: The long-term administration of lamivudine for patients with decompensated cirrhosis B is effective and safe, although breakthrough and non-response occurred in some patients.

PCNA expression and electron microscopic study of acinus-forming hepatocytes in chronic hepatitis B.

BACKGROUND: One of the major morphologic characteristics of hepatitis B is a hepatocellular regeneration which is induced by massive hepatocyte necrosis and associated with proliferative activity of hepatocytes. The purpose of this study is to document the proliferative activity of hepatocytes in various types of hepatitis B by immunohistochemical staining for proliferative cell nuclear antigen-labelling index (PCNA-LI) and electron microscopy. METHODS: We studied 83 patients with hepatitis B: 11 cases of acute viral hepatitis, 24 cases of mild chronic hepatitis, 34 cases of severe chronic hepatitis with early cirrhosis and 14 cases of severe chronic hepatitis. The PCNA was tested by immunohistochemical staining using anti-PCNA antibody. Furthermore we evaluated the ultrastructure of acinus-forming hepatocytes (AFH) by electron microscopy. RESULTS: The expression rate and labelling index of PCNA were 27.3% and 5.3 +/- 0.9% in acute viral hepatitis, 62.5% and 22.9 +/- 31.7% in mild chronic hepatitis, and then 47.1% and 14.1 +/- 24.2% in severe chronic hepatitis with early cirrhosis, respectively (Figure 1). By contrast, no detectable PCNA expression was noted in AFH. Electron microscopic findings showed that hepatocytes forming a rosette underwent marked degenerative changes with sinusoidal capillarization and increased fine strands of collagen fiber in portal area. CONCLUSION: The proliferative activity of hepatitis B was significantly decreased in severe chronic hepatitis containing AFH. This result suggested that differences in proliferative activity was associated with hepatic cell necrosis and AFH.

p53 mutations and microsatellite instabilities in the subtype of intestinal metaplasia of the stomach.

To investigate the potential implication of the subtype of intestinal metaplasia in the progression to the gastric carcinoma, we analyzed the mutations of the p53 gene and microsatellite instability (MSI) both in the complete type (type I) and in the sulphomucin-secreting incomplete type (type III) intestinal metaplasia located adjacent to the gastric carcinoma. p53 mutations were observed in 13.3% of type I, in 6.6% of type III intestinal metaplasia, and in 40% of gastric carcinoma. The difference between p53 mutations observed in type I and type III intestinal metaplasia was not statistically significant. No identical mutation of the p53 gene was found in the intestinal metaplasia and carcinoma specimens from the patients. There was no case of intestinal metaplasia showing MSI. In gastric carcinomas, MSI was observed in six cases (40%). The cases harboring BAT-26 instability did not have the mutation of the p53 gene. These data suggest that intestinal metaplasia adjacent to gastric carcinoma, irrespective of its subtype, do not have the genetic alterations as showing in their carcinoma tissues.

The effect of the repeated subcultures of Helicobacter pylori on adhesion, motility, cytotoxicity, and gastric inflammation.

In vitro subcultures of bacteria can lead to genetic and phenotypic changes. This study aimed at investigating the effect of repeated subcultures on the adhesion, motility, cytotoxicity, and gastric inflammation caused by Helicobacter pylori. H.pylori SS1 strain was subcultured 64 times on agar plates containing Brucella broth and 5% bovine calf serum. The adhesion, motility, cytotoxicity, and gastric inflammation produced in Mongolian gerbils were compared between the first and 64th subcultured strain. The adhesion rates, following 3 hr exposure of AGS cells to either the first strain or the 64th-transferred strain, were 21% and 12%, respectively. The motility of the 64th-transferred strain decreased significantly when compared to the 1st strain (9.1 mm vs. 15.1 mm). The cytotoxicity index tended to be higher in the first strain than in the 64th-transferred strain (73.7% vs. 69.2%). The initial infection rate on the gerbils showed no difference between the two strains. However, chronic gastric inflammation of the first strain-infected gerbils was somewhat more severe than that of the 64th-transferred strain-infected gerbils. Therefore, the use of repeatedly subcultured strains of H. pylori in virulence experiments can lead to different results from those of the original strain.

Effects of selective cyclooxygenase-2 inhibitor and non-selective NSAIDs on Helicobacter pylori-induced gastritis in Mongolian gerbils.

BACKGROUND: It is still a point of controversy whether Helicobacter pylori-infected patients are more likely to develop mucosal damage while taking NSAIDs. Selective cyclooxygenase (COX-2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori-induced gastritis. The aim of this study was to evaluate the effects of selective COX-2 and nonselective NSAIDs on H. pylori-induced gastritis. METHODS: After intragastric administration of indomethacin, NS-398 or vehicle alone, once daily for 5 days in H. pylori-infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E2 (PGE2) concentration. We investigated whether H. pylori infection induced the COX-2 expression. RESULTS: In H. pylori-uninfected groups, the indomethacin-treated group showed the highest mucosal damage score and the lowest PGE2 concentration. There was no difference in mucosal damage scores and PGE2 concentration between NS-398 and vehicle-alone treated group. In H. pylori-infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin-treated group showed the lowest PGE2 concentration, similar to that of the NS-398 and vehicle-alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori-infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori-infected or uninfected groups. COX-2 protein expression was observed in H. pylori-infected Mongolian gerbils but not in uninfected ones. CONCLUSIONS: Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSAIDs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.

A case of pancreatic endometrial cyst.

Pancreatic endometrial cyst is an extremely rare instance of ectopic endometriosis that was first described by Marchevsky in 1984. A 21-yr-old woman with a history of epigastric pain and weight loss was found to have a cystic lesion in the pancreas on CT-scan. Under the tentative diagnosis of a pancreatic cystic neoplasm, partial pancreatectomy was performed. Histopathological examination of the specimen revealed cystic endometriosis. The clinicopathological features of the lesion are discussed and literature concerning this extremely rare lesion is reviewed.