Cultured cell model

In vitro studies examining the effects of diazepam in the immune system have shown mixed results. Several cultured cell models have demonstrated diazepam-induced inhibition of cell proliferation. 

Analysis of the Role of NTs in Sensitivity to Nucleoside Anticancer Drugs in Cultured Cell Models... 

Evidence obtained from in vitro studies (cultured cell models) clearly suggests that NTs contribute to nucleoside-derived drug cytotoxicity. Nevertheless, key issues are to determine whether these findings can be transferred to clinical settings and whether they will help to understand what roles NT proteins actually play in tumor responsiveness to nucleoside-based therapies. However, the lack, until recently, of suitable molecular tools such as isoform-specific anti-NT antibodies and the difficulty to obtain and analyze tumor samples have delayed this approach. Clinical studies suggesting a link between NT expression and drug sensitivity are summarized in Table 2.2. 

Various studies have addressed the antioxidant capacity of Pycnogenol in simplified assay systems in vitro, cultured cell models, perfused organs, and in vivo. Blazso and coworkers tested the in vitro scavenging activity of Pycnogenol as well as three... 

Our two network model of the primary wall receives support from a variety of indirect observations. For example it has been shown Aat when a cell wall is regenerated by a carrot protoplast a homogalacturonan/ rhamnogalacturonan shell is laid down first, through which the cellulose/ hemicellulose network is later intercalated (8). Further evidence that pectin may form an independent network is seen in the fact that walls from suspension-cultured cells of tofnato Lycopersicon esculentum VF 36),... 

We define this permeability as apparent, to emphasize that there are important but hidden assumptions made in its derivation. This equation is popularly (if not nearly exclusively) used in culture cell in vitro models, such as Caco-2. The sink condition is maintained by periodically moving a detachable donor well to successive acceptor wells over time. At the end of the total permeation time f, the mass of solute is determined in each of the acceptor wells, and the mole sum mA (t) is used in Eq. (7.10). Another variant of this analysis is based on evaluating the slope in the early part of the appearance curve (e.g., solid curves in Fig. 7.14) ... 

The in vitro measurements of permeability by the cultured-cell or PAMPA model underestimate true membrane permeability, because of the UWL, which ranges in thickness from 1500 to 2500 pm. The corresponding in vivo value is 30-100 pm in the GIT and nil in the BBB (Table 7.22). The consequence of this is that highly permeable molecules are (aqueous) diffusion limited in the in vitro assays, whereas the membrane-limited permeation is operative in the in vivo case. Correcting the in vitro data for the UWL effect is important for both GIT and BBB absorption modeling. 

Since the widely accepted in vitro permeability model in the pharmaceutical industry is based on the use of cultured cells, such as Caco-2 or MDCK, it was appropriate to analyze the regression correlation coefficients based on the comparisons of Caco-2 log Pe and the log Pe values based on the human jejunal measurements [56]. 

Cation and anion flux across cultured cell monolayers by molecular restricted diffusion within an electrostatic field of force across aqueous pores has been described with a model derived by Adson et al. (1994). The ion fluxes per cross-sectional area of the cell monolayer are defined as... 

Peehl, DM. 2004. Are primary cultures realistic models for prostate cancer J Cell Biochem 91 185-195. 

Several parameters of the larval niche have been evaluated in this in vitro model. Results indicate that T. spiralis establishes its niche in cell cultures. First, the broad host range of T. spiralis has been reproduced in cultured cells. The nematode is known to infect a diversity of vertebrate... 

The most commonly used methods for studies of partitioning into a membrane, mechanisms of drug absorption, and interactions with epithelial proteins, such as transporters and enzymes, are the cell culture-based models. These are both sim-... 

For the evaluation of a possible relationship between the molecular structure of a potential candidate and its transport abilities to cross the epithelial membrane of the gut, the mechanism or route of transport must be known [1,4]. This is due to the structural requirements for the transcellular route being different from the paracellular route. During the lead optimization phase - when many mechanistically based studies are performed - the cell culture-based models can also be used with great confidence. 

Both active and passive transport occur simultaneously, and their quantitative roles differ at different concentration gradients. At low substrate concentrations, active transport plays a major role, whilst above the concentration of saturation passive diffusion is the major transport process. This very simple rule can be studied in an experimental system using cell culture-based models, and the concentration dependency of the transport of a compound as well as asymmetric transport over the membrane are two factors used to evaluate the presence and influence of transporters. Previous data have indicated that the permeability of actively absorbed compounds may be underestimated in the Caco-2 model due to a lack of (or low) expression of some uptake transporters. However, many data which show a lack of influence of transporters are usually derived from experiments... 

Artursson, P., Cell cultures as models for drag absorption across the intestinal mucosa, Crit. Rev. Ther. Drug Carrier Syst. 1991, 8, 305-330. 

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