Objective It has been known that the C-terminal domain of rodent Muc3 underwent proteolytic digestion.G/S within the motif of cleavage,LSKGSIVV,was one of the important pivots for digestion.The present investigation was aiming at exploring the unknown relationship between the integrity of SEA module and the proteolytic digestion.Method Truncated rodent Muc3 C-terminal domains(p20t and p20SEA) were produced by site-directed mutagenesis to insert a stop code in the required place.Proteins were detected by SDS/PAGE and Western blotting.Deglycosylation of the expressed protein was performed by digestion using N-glycosidase F.Results Muc3 C-terminal domain was posttranslationally cleaved to produce a V5-tagged 30kDa extracellular glycopeptide and a Myc-tagged 49kDa membrane-associated glycopeptide.The 30kDa N-terminal fragment shifted to 22kDa after deglycosylation.The truncated rodent Muc3 C-terminal domain containing complete SEA module,but without the following residues after SEA module,was 30kDa Mw as detected with anti-V5 antibody,and it was shifted to 22kDa after deglycosylation.But the truncated rodent Muc3 C-terminal domain containing incomplete SEA module(p20t) of 26-30kDa Mw was shifted to 26kDa after deglycosylation.Conclusion There was proteolytic digestion in both complete rodent C-terminal domain and complete SEA module without residues after SEA module.But proteolytic digestion does not occur in the incomplete SEA module of rodent Muc3.So it may be concluded that the integrity of SEA module of rodent Muc3 was also a crucial condition for its proteolytic digestion.

Objective The study was to explore the relationship between Helicobacter pylori ( H.pylori ) infection and aberrant mucin expression in gastric mucosa. Methods H.pylori infection was diagnosed by Warthin Starry staining method, and different kinds of mucin were detected using the immunohistochemical method. Results Positive staining of MUC2 mucin was found in 14 out of 21 patients with mucosa positive for H.pylori ( 66 7%), whereas only 6 cases showed MUC2 mucin expression in 18 H.pylori negative patients (33 3%) ( P 0 05). Conclusion H.pylori infection may alter the expression of some mucin genes in pericancerous gastric mucosa and destroy the gastric mucosa barrier

Objective To study of relationship of the mRNA expression of protection of telomeres 1(POT1) and the activity of telomerase with the incidence of gastric carcinoma.Methods Lesioned gastric mucosal tissues and the corresponding normal tissues from 30 cases of gastric cancer,30 cases of moderate or severe atypical hyperplasia,and 30 cases of intestinal metaplasia were collected in this study.The expression of POT1 mRNA was detected with real time-PCR and the activity of telomerase was examed with TRAP-ELISA.Results Real time-PCR analysis showed that POT1 expression was increased in the gastric carcinoma tissues compared with the paracancerous normal mucosal tissues,increased in the severe atypical hyperplasia than in the corresponding normal tissues,but there was no difference between intestinal metaplasia tissues and normal tissues.The activity of telomerase in the advanced gastric tumors and severe atypical hyperplasia was significantly higher than that in intestinal metaplasia tissues and normal gastric mucosal tissues.However no obvious difference was found in the activity in gastric tumors and severe atypical hyperplasia with intestinal metaplasia tissues and normal gastric mucosal tissues.Conclusion Although the activity of telomerase in gastric cancer and severe atypical hyperplasia is significantly higher than that in normal and intestinal metaplasia tissues,POT1 mRNA has no relationship with this change.

Objective To explore the existing molecular pattern of rodent Muc3 carboxyl-terminal domain. Methods Muc3 carboxyl-terminal domain was expressed by a transient expression system and detected with SDS/PAGE and Western blotting. Identification of interaction between two proteolytically cleaved fragments was carried out by using both metabolic labeling and immunoprecipitation of expressed proteins and affinity purification of His-tagged proteins. Results Experiments with heterologous cells transfected with cDNA encoding the 381-residue C-terminal domain of rodent Muc3 showed that a definitive proteolytic cleavage occurred during the process in the endoplasmic reticulum. The products consisted of a V5-tagged 30 000 extracellular peptide, a Myc-tagged 49 000 membrane-associated peptide and non-cleaved 55 000 of whole-length protein. Two fragments remained associated by non-covalent SDS-sensitive interactions. Conclusion The proteolytic cleavage may be a prelude to later release of the large extracellular domains at cell surfaces. But the interaction between two cleaved fragments may be an important factor to interfere with the later release of the extracellular domain.

This article is to evaluate the role of DCC gene alteration in the development and progression of gastric cancer, as well as to correlate with its prognosis. Loss of heterozygosity (LOH) at DCC gene was examined in 45 cases of surgically resected gastric cancer tissue. LOH at the DCC locus was detected in 15/45(33.3%), and it was found to be closely related to clinical staging, but not to the histologic types, depth of tumor invasion or lymph node metastases. These results suggest that LOH at the DCC locus occurs in late stage of the disease and detection of LOH at the DCC locus may be useful for predicting the prognosis of the gastric cancer patients.

Objective The development and progression of intestinal metaplasia ( IM ) and expression of tumor-related proteins in dog’ s stomach were observed. Methods IM animal model was established in Beagle’ s stomach by feeding N-methyl-N’-nitro-N-trosoguanidine( MNNG ),ranitidine,and local X-irradiation. Expression of APC, p53, K-ras and bcl-2 genes in canine gastric lesion were determined by immunohistochemistry. Resullts IM canine model was successfully induced, with which sequential pathology studied. It was proved that progression of normal epithelial cells to IM cells might undergo several stages including superficial gastritis, chronic atrophic gastritis, mild focal IM, moderate,and severe IM.Aberrant bcl-2 protein was detected in atrophic gastric epithelium and abnormal expression of APC, K-ras, and bcl-2 found in IM mucosa. Conclusion Canine gastric IM was induced by the method mentioned above.The development of normal gastric mucosa to IM in dog seemed to resemble that of human being.The presence of tumor-related proteins might indicate the transformation of IM to malignancy.

Objective To evaluate the role of OMOM capsule endoscopy in diagnosis of colon diseases.Methods Forty-six patients with suspected colon diseases,aged 18 to 68,voluntarily underwent the examination with the OMOM capsule endoscopy and colon endoscopy after informed the aim of the study.Patients who were suspected with colon stenosis or obstruction were excluded from the study.The outcome were compared with the results of common colonoscopy.The sensitivity,specificity and accuracy of OMOM capsule endoscopy were analyzed.Results OMOM capsule endoscopic examination were completed successfully in 40 of 46(87.0%) patients.For diagnosis of colon diseases with OMOM capsule endoscopy,the sensitivity was 57.7%,the specificity was 85.7%,and the accuracy was 67.5%.While,the positive predictive value was 88.2%,and the negative predictive value was 52.2%.The positive likelihood ratio was 4.04 and the negative likelihood ratio was 0.494.The bowel preparation had direct influence on examine.Polyethylene Glycol 4000 combined with 50% salamarum had better colon clearness.Conclusion OMOM capsule endoscopy is a safe,non-invasive method,and can provide definitive diagnosis in colon diseases.The bowel preparation is important for successful examination.

Objective To study the mechanism of cisapride in the treatment of gastricelectric dysrhythmia. Methods Cisarpride was gavage fed to rats in which gastricelectric dysrhythmia hed been reproduced. The cholinergic and nitriergic nerves in myenteric plexus of gastric antrum were examined with histochemical staining methods and whole mount preparation technique. The levels of cAMP and cGMP in the antral smooth muscle were measured by radioimmunoassay. Results Gastricelectric dysrhythmia in the model group was ameliorated after the treatment with cisapride(P

Objective To study the expression of hTERT in human gastric carcinoma and its precancerous lesions and to explore the relationship between hTERT expression and Helicobacter pylori (Hp) infection. Methods hTERT expression was detected by immunohistochemical method. Hp was detected by rapid urease test and Warthin-Starry silver staining. Results The expression level of hTERT in human gastric carcinoma (78.95%) was significantly higher than that in gastric dysplasia (64.29%), in intestinal metaplasia (46.67%), and in atrophic gastritis (25.00%, P

Objective To study the expression of hTERT protein in precancerous lesions of human stomach, and to analyze the relationship between telomerase activity and cell apoptosis, in order to elucidate the effects of telomerase activity and cell apoptosis in the pathogenesis of gastric carcinoma. Methods Sp method was employed to detect the hTERT expression and the apoptosis was determined in situ by TUNEL staining in 64 patients with chronic gastritis and gastric carcinoma. Among the 64 patients, 16 suffered from chronic gastritis with gastratrophia, 15 with intestinal metaplasia, 14 with allotypic proliferation, and the 19 remainders suffered from gastric carcinoma. Results (1) The respective positive frequency of hTERT protein expression in chronic gastritis, intestinal metaplasia, gastric allotypic proliferation and human gastric carcinoma were 25.0%, 46.7%, 64.3% and 78.9%. The positive frequency of hTERT protein expression in human gastric carcinoma was significantly higher than that in gastric allotypic proliferation, intestinal metaplasia and chronic atrophic gastritis (P