[Application endoscopic mucosal resection to therapy early gastrointestinal cancer and precancerous lesion].

OBJECTIVE: To explore the clinical value of endoscopic mucosal resection (EMR) on early gastrointestinal cancer and precancerous lesion. METHODS: The EMR data of 42 lesions from 28 patients, collected from Apr. 2001 to Dec. 2005, were retrospectively analyzed. All the lesions were confirmed histologically before and after operation. RESULTS: Forty-two lesions were removed by the EMR from 28 patients. Lesion types observed under endoscopy were as follows: type I 9 lesions (type Isp 2 lesions, type Is 7 lesions), type II 33 lesions (type IIa 23 lesions, type IIa + IIc 4 lesions, type IIb 6 lesions). Thirty-eight EMRs were performed by using snare resection techniques and 4 EMRs by using suction cap-assisted techniques. The size of lesions changed from 0.6 cm x 0.6 cm to 3.0 cm x 3.5 cm. Complete resections were achieved in 36 of 40, among them, 2 lesions were divided into 2 pieces and 1 lesion was divided into 3 pieces. Post-EMR histopathologic evaluation revealed the following RESULTS: carcinoma in 4 lesions, high-grade dysplasia (HGD) in 11 lesions, middle-grade dysplasia (MGD) in 17 lesions, adenoma in 6 lesions, non-adenoma in 2 lesions. The pathology match rate between local biopsy and EMR was 60.0%. The detection rates of cancer, HGD and MGD by EMR were higher than that by routine biopsy. No serious complications were seen in this study. CONCLUSION: Endoscopic mucosal resection has significant impact on the endoscopic intervention treatment of early cancer and precancerous lesion in digestive tract.

Effects of folic acid on epithelial apoptosis and expression of Bcl-2 and p53 in premalignant gastric lesions.

AIM: To evaluate the effects of folic acid on epithelial apoptosis and expression of Bcl-2 and p53 in the tissues of premalignant gastric lesions. METHODS: Thirty-eight patients, with premalignant gastric lesions including 18 colonic-type intestinal metaplasia (IM) and 20 mild or moderate dysplasia, were randomly divided into a treatment group (n = 19) receiving folic acid 10 mg thrice daily and a control group (n = 19) receiving sucralfate 1,000 mg thrice daily for 3 mo. All patients underwent endoscopies and four biopsies were taken prior to treatment and repeated after concluding therapy. Folate concentrations in gastric mucosa were measured with chemiluminescent enzyme immunoassay. Epithelial apoptosis and the expression of Bcl-2 and p53 protein in gastric mucosa were detected with flow cytometric assay. RESULTS: The mean of folate concentration in gastric mucosa was 9.03+/-3.37 microg/g wet wt in the folic acid treatment group, which was significantly higher than 6.83+/-3.02 microg/g wet wt in the control group. Both the epithelial apoptosis rate and the tumor suppressor p53 expression in gastric mucosa significantly increased after folic acid treatment. In contrast, the expression of Bcl-2 oncogene protein decreased after folic acid therapy. CONCLUSION: These data indicate that folic acid may play an important role in the chemoprevention of gastric carcinogenesis by enhancing gastric epithelial apoptosis in the patients with premalignant lesions.

Construction and high-level expression of a single-chain Fv antibody fragment specific for acidic isoferritin in Escherichia coli.

A functional single-chain Fv antibody fragment (scFv) specific for acidic isoferritin (AIF) was produced at high level in Escherichia coli. The variable regions of heavy chain (V(H)) and light chain (V(L)) from the hybridoma 4c9 were connected with a flexible linker using an assembly polymerase chain reaction. The construct of V(H)-linker-V(L) was inserted into a phagemid pCANTAB 5 E followed by selection with the Recombinant Phage Antibody System (RPAS). Anti-AIF scFv gene from the recombinant phagemid pCAN4c9 was subcloned into pET28a fused to N-terminal His-tag sequence in frame and overexpressed in E. coli BL21(DE3). With an on-column refolding procedure based on Ni-chelating chromatography, the active anti-AIF scFv was recovered efficiently from inclusion bodies with a refolding yield of approximate 75% confirmed by spectrophotometer. The activity of refolded scFv was determined through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting and enzyme-linked immunosorbent assay. The results showed anti-AIF scFv retains the specific binding activity to AIF with an affinity constant of 7.29 x 10(-8) mol l(-1). The overall yield of anti-AIF scFv with bioactivity in E. coli flask culture was more than 60 mg l(-1).