Immature primary cultures

Many models are currently being used to study apoptosis. These include the study of growth factor-deprived cell cultures, cells treated with radiation or cytoxic agents, vims-infected cells and many models in vivo and in vitro of programmed or developmental cell death. In this review, we will concentrate on models of developmental cell death. These include developmental cell death in the nematode, C. elegans, primary cultures of neurotrophic-dependent neurons, the pheo-chromocytoma cell line, PC 12, and primary cultures of immature thymocytes. Studies involving these models of cell death have defined molecules and pathways that may be important in a wide variety of types of apoptosis. 

Fig. 2. Phase-contrast of rat pure oligodendrocytes after 25 days in culture (20 days in primary culture + 5 [Pg.119]

The development of parallel-plate perfusion chambers [67,68] made possible the study of platelet interaction with the extracellular matrix (ECM) generated by cells in culture or with isolated subendothelial components under defined experimental conditions. The use of the ECM produced by human umbilical vein endothelial cells (HUVEC) in culture as adhesive substrate has Su tated the understanding of the mechanisms involved in primary hemostasis [68]. HUVECs are immature and not subjected to flow conditions during their culture, two Ikctors which may influence the reactivity of their ECM towards platelets [69]. Interestingly, the properties and reactivity of the underlying ECM can be modified by exposure of HUVECs to different stimuli, an experimental approach which has fevored the investigation of basic mechanisms of thrombosis [33]. 

A bilayer scaffold including an outer layer of an electrospun PEUU scaffold and an inner layer of porous PEUU scaffold was developed to address the cellular-ization issue [15]. The electrospun layer provided the mechanical support, while the porous scaffold layer supplied space for cell loading and infiltration. Prior to implantation, the cells including primary cells or stem cells were uniformly seeded into the porous layer using a customized vacuum device [15,40 2]. Rat vascular smooth muscle cells were seeded into the bilayer conduit and cultured in vitro for 2 days, and then this cellularized scaffold was implanted into the rat aorta model [42]. After 8 weeks, the patency of the cellularized scaffolds increased by 75% compared to 38% of the acellular scaffold. The failed scaffolds were blocked due to the intimal hyperplasia. The patent scaffolds contained a neointimal layer consisting of multiple layers of the immature contractile smooth muscle... 

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