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Objective:To methodologically establish the lentivirus granule packaging, concentration and infection against CD34~+ cells from umbilical blood. Methods:The lentivirus system of the 3~(rd) generation was used to produce the virus. Ultrafiltration and ultracentrifugation were employed to concentrate virus. Several treatments were used to improve virus infection including in vitro amplification culture, facilitation of rest cells into cell cycle, promotion of cell adhesion and immobilization during infection, and repeat infection methods. Results:CD34~+ cells were not obviously changed by checking the expression level of CD34 marker on the cell surface after 48 h culture. After two-step concentration, virus titer was increased up to 5.06×10~7/ml, and the infection rate against CD34~+ cells from umbilical blood was increased up to 37.7%.Conclusion:Lentivirus supernatant with over 10~7/ml titer can be obtained using the above methods. Efficient infection against CD34~+ cells from umbilical blood can be achieved.
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<p><b>OBJECTIVE</b>To explore the relationship between the proliferation, differentiation of rat hepatic stem like cell line WB-F344 and cytokines in vitro.</p><p><b>METHODS</b>(3)H thymidine labelling of new synthesized DNA was used to examine the mitogenic responsiveness of WB-F344 cells to cytokines, western blot was used to study the expression of cytokines receptors on hepatic stem cells, and apoptotic cells were detected by Flow cytometry.</p><p><b>RESULTS</b>WB-F344 cells showed a proliferative response to the cytokines of hepatocyte growth factor (HGF), epidermal growth factor (EGF), fibroblast growth factor (FGF), Insulin at the dose of 80 ng/ml, and the relative cpm values are 982.95, 906.32, 863.98 and 968.67 respectively, while non response to interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) at the same dose, and an inhibition or apoptosis response to transforming growth factor-beta (TGF-beta) at 80 ng/ml with a 26.89% apoptotic rate. Western blot showed that there were HGF, EGF, FGF, TGF-beta receptors expressed on WB-F344 cells. When WB-F344 cells were cultured in the differential system (DMEM, 10% Fcs, HGF 10 to approximately 50 ng/ml, EGF 20 ng/ml, Insulin 1 microg/ml, Dex 1 micromol/L), the cells could differentiated into hepatocytes. In addition, HGF could scattered WB-F344 cells.</p><p><b>CONCLUSION</b>The proliferation and differentiation of liver stem cells are regulated by various cytokines which may play an important role when liver is damaged seriously.</p>