It is assumed that the same model is applicable both in vivo and in vitro. Materials and methods: In the present study, we compared proliferating marrow cells freshly isolated from healthy individuals with proliferating
lymphocytes in cultures. Results: We demonstrate that during progression of freshly collected human bone marrow cells through G(1), S and G(2)/M, only Cdk1 combined with cyclins A and B(1) was distinctly present and active, and its activity gradually increased. In contrast, in vitro growing mitogen-stimulated lymphocytes had perfectly scheduled sequential expression of all four cyclins and Cdk1 and Cdk2 activities. Conclusion: Our findings demonstrate that the pattern of cyclin expression
and Cdk activity in bone marrow in vivo is distinctly different from the one observed for normal cells in vitro. Because proliferating bone marrow cells ATM Kinase Inhibitor are predominantly expanding populations of committed progenitors, it is likely that during the expansion phase their cell-cycle progression is pre-programmed, being driven solely by Cdk1 combined either with cyclin A or with cyclin B(1). Expansion of progenitor cells thus may not require buy CBL0137 the early steps of cell-cycle regulation, associated with triggering progression by availability of growth factors and mitogens.”
“Development of technology to deliver foreign gene(s) to a specific organ/tissue is one of the major challenges in gene therapy. Here, we show liver- and lobe-specific gene transfer following the continuous microinstillation of plasmid DNA (pDNA)
onto the liver surface in mice. Naked pDNA was continuously instilled onto the right medial liver lobe using syringe pump in male ddY mice. Our previous studies showed liver- EX 527 inhibitor and lobe-selective gene expression after instillation of 30 mu l of pDNA solution onto the liver surface, but gene expression was also found in the other liver lobe, kidney and spleen. To improve target site selectivity of gene expression, the instillation volume was decreased; however, non-specific gene expression in the other liver lobe and diaphragm was still detected. To prevent immediate diffusion of the pDNA solution, we performed continuous microinstillation of pDNA using a syringe pump; as a result, target site selectivity was greatly improved. As for instillation speed, 5 min infusion was enough to prevent diffusion of pDNA solution. 123 Furthermore, transfection efficiency in the target site was maintained when instillation speed was slowed. Wiping off residual pDNA solution from the applied liver lobe resulted in a further improvement in selectivity, suggesting not only immediate diffusion, but also gradual diffusion, are important factors for successful target site-specific gene transfer.