Cell culture cellular uptake

Two studies have used single cells to study the effect of phenolic acids on mineral absorption. In sterile cell cultures of Paul s Scarlet rose, 100 pM ferulic acid inhibited Rb+ absorption in about 10 min when the cells were 4-5 days old (37). Uptake from 0.2 mM RbCl was inhibited about 25% and absorption from 5.0 mM RbCl was inhibited 45%. Absorption by 10-day-old cells was affected little. Salicylic acid at 10 pM inhibited PO - absorption by Scenedesmus, a unicellular green alga (38). These studies show that allelochemicals inhibit mineral absorption in cellular systems as well as tissue systems (Table I). 

The advantageous effects of liposomal carrier systems include protection of compounds from metabolism or degradation, as well as enhanced cellular uptake. Liposome-mediated delivery of cytotoxic drugs to cells in culture has resulted in improved potency [58,59]. Prolonged release of encapsulated cargo has also been demonstrated [60,61]. More recently, liposomes with extended circulation half-lives and dose-independent pharmacokinetics (Stealth liposomes) [62] have shown promise in delivery of drugs that are normally very rapidly degraded. 

Thus, in contrast to previous in vivo models, this in vitro model provides the possibility of dissociating experimentally two important processes of the intestinal carotenoid absorption cellular uptake and secretion. Under conditions mimicking the postprandial state (TC OA supplementation), differentiated Caco-2 cells were able (1) to take up carotenoids at the apical side and to incorporate them into CM and (2) to secrete them at the basolateral side, associated with CM fractions. In this model, no attempt has yet been made to reproduce the in vivo physiochemical conditions occurring in the intestinal lumen, such as carotenoid release from the food matrix and solubilization into mixed lipid micelles. Carotenoids were delivered to Caco-2 cells in aqueous suspension with Tween 40 (During et al., 2002). Using this cell culture system in conjunction with an in vitro... 

In cell culture, lycopene is a highly oxidizable nonpolar hydrocarbon supplied in an aqueous medium and is incubated at body temperature for 12-72 h. The amount of intact lycopene or its oxidation products delivered to and absorbed by various cell types is an important factor to keep in mind when evaluating the effects of lycopene on various cellular processes. Before reviewing cell culture studies designed to characterize the effects of lycopene on prostate cell biology, the characteristics of prominent prostate cell lines, and the stability and uptake of lycopene by various prostate cell lines are reviewed. 

The cellular uptake appears to be a passive process, the cellular distribution being dependent on cell type. In cultured pneumocytes, the cell membrane was... 

Cellular uptake of AS-ODNs is restricted because of their large molecular mass as well as their polyanionic character. When added directly to cells in culture, only 1-2% of the AS-ODNs will be cell-associated. Therefore, enhanced AS-ODN uptake is a critical consideration in developing these agents for therapeutic applications. 

The regulatory mechanism of cellular uptake of fatty acids appears to be limited and so the composition of the intracellular lipids is likely to reflect the availability of the fatty acids in the medium. This was shown for the CC9C10 hybridoma (Butler et al., 1997) and for BHK and CHO cells (Schmid et al., 1991). Thus, cells growing in serum-supplemented cultures are likely to attain a fatty acid composition reflecting that of serum, in which the predominant fatty acids are palmitic, stearic, oleic, and linoleic acids at a ratio 2 1 3 1, respectively. 

The major obstacle to PNA use so far has been poor uptake by most cells and tissues. Therefore, delivery systems based mainly on the use of peptide vectors have been developed. Recent studies, on the other hand, demonstrate that neuronal tissues or cells are an exception to this general rule and spontaneously take up PNA (13-16). The reason for this is not clear, but the fact is that if injected directly into neuronal tissue, or applied to a neuronal cell culture, a delivery vector is not obligatory for cellular uptake of PNA oligomers. 

It is clear from the above studies that in vitro renal cell culture can be used successfully to study the cellular and molecular mechanisms of cell modulation by toxic compounds. Such systems allow a simple but sophisticated approach to the development of strategies to overcome nephrotoxicity of many important drugs. A cartoon summarizing the major pathways of uptake and extrusion of specific nephrotoxins and common mechanisms of cellular toxicity, derived from in vitro renal cell culture studies is given in Figure 2. 

Some of these antitemplates have shown significant cytotoxicity in bacterial and mammalian cell culture assay systems126 . There is considerable evidence in the literature132 that bacterial and mammalian cells are capable of taking up intact DNA and RNA molecules. It has been suggested recently that one approach to cancer chemotherapy may be the uptake of normal RNA molecules or specifically defined oligonucleotides 133 . From the point of view of cellular uptake, the increased resistance which these antitemplates demonstrated toward the action of various nucleases appears to be particularly fortuitous. 

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