Objective:To study the effects of supranutrional levels of yeast-selenium on antioxida-tion status and immune function in mice with tumour.Method:Sixty KM mice were divided into three groups: control group,yeast-selenium Ⅰ group and Ⅱgroup.The mice were supplemented with 0.5ml normal saline,3.2 ?g and 6.4 ?g yeast-selenium respectively by gavage on time a day based on the low selenium diet.The mice were inoculated with Ehrich ascites carcinoma(EAC) after 13 d.The tumour weight and immune function and antioxidative indices in blood were measured after 23 d.Results: The two yeast-selenium levels increased the activities of GSHPx(P

Objective To construct five shRNA-expression plasmids and to investigate the expression of Smad2 in TGF-?/ Smads signal transduction treated with shRNA-expression plasmid.Methods Five shRNA-Smad2 DNA sequences from mRNA sequence of mouse Smad2 gene were designed and synthesized.DNA oligonucleotides encoding an appropriate shRNA were inserted to shRNA expression vector respectively.Five shRNA-Smad2 expression plasmids were obtained and then transfected into NIH/3T3 cells.The suppressed expression of Smad2 was assessed by RT-PCR and Western-blotting.Results The shRNA-expression plasmid numbered 2.4 could markedly reduce the expression of Smad2.The suppression effect of the RNAi-pool composed of four different plasmids was more obvious than that of any single.Conclusion The shRNA-expression plasmids were successfully constructed,which could specifically and effectively suppress the expression of Smad2.The method of using a mixture of RNAi plasmids to improve the RNAi efficiency was established.