Cell model systems

We recently conducted experiments to extract mRNA from a cell model (MBA-MB-486 cell line of human breast cancer) processed in both frozen and FFPE blocks in a comparable fashion (unpublished data). The cell model system was prepared in three ways for comparison (1) Positive Control Fresh Cell Pellet Two flasks of cells were collected in a pellet, and stored at -70°C until use (2) Frozen Cell Block Two flasks of cells was embedded in OCT... 

Compound (Miles Laboratories, Elkhart, IN), snap-frozen, and cut into sections for comparison with paraffin-embedded cell sections (3) FFPE Cell Blocks Six cell pellets were fixed in 10% neutral buffered formalin immediately after harvest, at room temperature for 6,12,24h, 3,7, and 30 days, respectively. For further comparison with the cell model system, recently collected sample of human breast cancer tissues were processed by OCT-embedding and snap-freezing the corresponding routine FFPE block that was obtained from the Norris Cancer Hospital and Research Institute at the University of Southern California Keck School of Medicine (USC). This tissue block was processed routinely (formalin-fixed 24h and processed by automatic equipment). 

Nojeim et al (utilized an electrolytic cell model system, free of oxygen, buffered with phthalate to pH k.2 and designed to provide a redox potential between +300 and +650 mv to evaluate the effect of redox potential on the ionization and valence of four iron compounds El, FS, FOP, and SFEDTA, described previously (1+3.). Data obtained were used to predict ionization and valence trends in actual food systems of different redox potentials. Redox potential was found to have no significant effect on the ionization of any of the four compounds evaluated. However, in the case of El and FS lower potentials in the environment favored the reduced form of iron. This is to be expected since a greater difference between the +770 mv potential of the ferric to ferrous couple and the potential of its chemical environment would cause the reduction to be more spontaneous. 

Boudreau, R.T.M. and Hoskin, D.W., The use of okadaic acid to elucidate the intracellular role(s) of protein phosphatase 2A lessons from the mast cell model system, Int. Immunopharmacol, 5, 1507,... 

Ghitun, M., Bonneil, E., Fortier, M. H., Yin, H., Killeen, K., and Thibault, R, Integrated microflu-idic devices with enhanced separation performance apphcation to phosphoproteome analyses of differentiated cell model systems, J. Sep. ScL, 29, 1539, 2006. 

In the ZAHNER controlled intensity modulated photocurrent spectroscopy (CIMPS) system, the light source and the cells are aligned on an optical track. Switching between the reference and the measurement cell is automatic. A close-up of the measurement cell is shown in Figure 15.41, set up for a study of a multilayer organic solar cell model system, shown schematically on the left side. In the PECC-2 cell shown, the reference electrode is Ag/AgCl and the CE is a Pt coil. The cell construction from PTFE or similar polymers allows the use of aggressive and nonaqueous electrolytes. 

Kutty G, Hayden B, Osawa Y, Wiggert B, Chader GJ, Kutty RK. Heme oxygenase expression in human retina and modulation by stress agents in human retinoblastoma cell model system. Curr Eye Res 1992 11 153-160. 

R. J. Pienta, A hamster cell model system for identifying carcinogens, in Carcinogens Identification and Mechanisms of Action (A. C. Griffin and C. R. Shaw, eds.), pp. 121-141, Raven Press, New York (1979). 

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