Quality standardized test cells

When a new batch of cells is started up from liquid nitrogen storage, the quality of the cells should be tested by performing a standard 10-day differentiation protocol, as described in Differentiation into cardiomyocytes by performing a test without a compound and in the presence of 5-FU to verify the sensitivity of the assay. 

Check the cell for the performance measurement The quality of the measurement depends strongly on the quality of the cell used. Always use the highest-quality cell available. Make sure that the cell is clean and free of contamination. Contamination can change the absorbance of standard solutions, resulting in failure of the photometric accuracy test. The optical quality of the cell is affected by factors such as closeness to the specified path length, parallelism of the inner and outer faces of the windows, and flatness of the window. Upon... 

TEER, normalized to surface, was 188-221 Ohm/cm2 in CACO-2 cells and 78-125 Ohm/cm2 in colon (Rubas et al. 1996). The presence of villi and crypts in vivo with a higher surface and a different cellular composition (goblet cells, M cells, higher permeability in crypts) compared to a cell mono-layer might lead to higher permeability. Tanaka et al. (1995) compared permeability of FITC-Dextran (MW 4000) in CACO-2 cells and rat jejunum and colon the permeability was 10 fold decreased in CACO-2 compared to jejunum and 5 fold lower than in colon. TEER in CACO-2 was 470 Ohm x cm2 in this study, 40 Ohm x cm2 in rat jejunum and 80 Ohm x cm2 in rat colon. Permeability of standard markers like PEG was compared between CACO-2 cells and colon (Artursson et al. 1993). The conclusion for cellular studies is to select cells with acceptable TEER and permeability values and to perform quality assurance tests on a regular basis. 

The important question arises of the actual precision of pH measurement in analytical control. In this connection, it has become common practice to standardize pH determinations, on standard buffer solutions with pH regions where the pH of the solution under test is to be expected. As currently commercially available pH meters, pH electrodes and buffer solutions are of outstanding quality, the reliability of the pH measurement becomes shifted to the performance of the measuring electrochemical cell here as first principle the same cell should be used for the test solution and the standard solution, so that according to the Bates-Guggenheim convention... 

STANDARD REFERENCE MATERIAL CELL LINE DEVELOPMENT AND USE OF REFERENCE CELL LINES AS STANDARDS FOR EXTERNAL QUALITY ASSURANCE OF HER2 IHC AND ISH TESTING... 

ISO 10712 (1995) Water quality Pseudomonasputida growth inhibition test (Pseudomonas cell multiplication inhibition test). International Organization for Standardization, Geneva... 

ISO/DIS 10712. Water Quality — Pseudomonas putida growth inhibition test (Pseudomonas Cell Multiplication Inhibition Test) International Organization for Standardization Geneve, 1995 14 pp. 

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