Cellular individually isolated cells

The immediate and reversible actions of dopamine are a combination of modulations of individual ion channels. The major ion channels expressed in spiny projection neurons are summarized in Table 2. Current understanding of the properties of these channels is mostly based on whole cell recordings from isolated cells, which have been recently reviewed by Nichola et al. (2000). The role of these channels in whole cell behavior has been studied using intracellular recordings in brain slices or anaesthetized animals. Many of the important cellular properties of spiny projection neurons can be accounted for in terms of ion channel activations occurring at different membrane potentials. 

Kinter AL, Umscheid CA, Arthos J, et al. HIV envelope induces virus expression from resting CD4+ T cells isolated from HIV-infected individuals in the absence of markers of cellular activation or apoptosis. J Immunol 2003 170(5) 2449-2455. 

In chapter 3 the experimental route to isolation of individual classes of phospholipids from cellular preparations was described in some detail. Either a column-chromatographic or a thin-layer chromatographic (TLC) procedure can be used here. If preparative TLC plates (normally silica gel G) are available, the separation of sphingomyelin from its most likely contaminant, phosphatidylcholine, is easily accomplished. The only other probable contaminant would be monoacylglycerophosphocholine (lysolecithin), but it is usually present in very, very low concentrations. If only a relatively few cells are available for lipid extraction, the TLC route is the procedure of choice. If milligram quantities of sphingomyelin are desired, then the cell of choice is the bovine erythrocyte and the isolation can be accomplished as described by Hanahan (1961). 

In order to assess their capacity to produce and process recombinant proteins we introduced the Ui-antitrypsin gene driven by a mouse CMV/EFl-a hybrid promoter together with selection markers into one of the cell clones derived from neuronal precursors. Twelve individual clones were isolated and specific cellular productivity was determined. Several of the clones secreted more than 75 pg celT day , at least 6-fold more than the best CHO or G-line based producers isolated for this protein so far. Titers of 0.5 g L accumulated over 17 days of stationary culture in T-flasks. 

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