Objective To construct eukaryctie expression vectors stably expressing Smad-7 and study its function as TGF-β1 inhibi- tor. Methods Smad-7 genes were obtained by PCR from fetal liver cDNA library and inserted in to eukaryotic expression plasmid pcD- NA3. 1/myc-his-B (-). The constructed plasmids containing right sequence of target genes were transfected into human mesangial cells by lipofectamine. The ceils were selected by G418, the expression of Smad-7 was detected by Western-blotting. Cell proliferation was detected by MTT method, and cell cycle was detected by Flow Cytometer to study its function as TGF-β1 inhibitor. Results We successfully con- struct Smad-7 expression plesmid. Smad-7 can inhibit the effects of TGF-[M induced GI cell cycle block and apoptosis. Conclusion The eukaryotic expression vector of Smad-7 has been successfully constructed. Over-expression of exogenous Smad-7 can inhibit the effects of TGF-β1 induced GI cell cycle block and apoptosis.

Objective To explore the isolation, culture of nestin positive cells of the pancreas in newborn rats. Methods The whole pancreas of neonatal rats were digested with collagenase, followed by incubation under pH 7. 6 serum RPMI 1640 for 24 - 36 h and then under pH 7. 4 serum free RPMI 1640 (bFGF.EGF 20 ng/ml.1% N2) for 18-24 d. The expression of insulin.glucagon and nestin were detected by immunofluorescence technique. Nestin.CK19 were detected by RT-PCR. Resides Cells attached to the surface of plates after 24 h incubation under pH 7. 6 condition, and islet-like masses were obtained after 18 -24 d incubation. A monolayer of cells grew out after 24 h of passage of islet-like masses. Nestin positive cells was detected after 24 - 36 h incubation, with no expression of insulin and glucagon. Positive cells of insulin and glucagon were detected in islet-like masses after 24 h passage. Nestin positive cells were detected by RT-PCR in islet-like masses after 24 h passage, but no CK19. Conclusion Insulin and glucagon were expressed in islet-like masses after passage. Nestin positive cells in the pancreas of neonatal rats possessed character of islet stem cells.