Cell inefficiency indicators

U373 cells compared with fibroblasts unless relatively large amounts of virus are added to the cells. Indeed, there was substantially less HCMV gene expression in virus-infected U373 cells compared with virus-infected fibroblasts (R. Tomazin, unpublished data). However, it is important to note that these observations are not inconsistent with effects of HCMV on the MHC class II pathway in vivo. More accurately, the inefficient inhibition of the class II pathway we observe in these HCMV-infected cells is indicative of the poor replication of HCMV in these cultured cells. We would argue that in vivo, in the appropriate cells, effects on the class II pathway are more robust and likely vital. 

Borm, B., Requardt, R. P., Herzog, V., KirfeL G. (2005). Membrane ruffles in cell migration indicators of inefficient lameflipodia adhesion and compartments of actin filament reorganization. Experimental Cell Research, 302(1), 83-95. http //dx.doi.Org/10.1016/j.yexcr.2004.08.034. 

The degree of inefficiency in a cell is indicated by the two products of the side reactions, oxygen in the chlorine and sodium chlorate in the cell liquor. Oxygen in the chlorine gas is the result of hydroxide ions that migrate through the diaphragm into the anolyte, where they are oxidized ... 

Figure 4.1 shows that NOs" is the stable form of nitrogen over the usual range of pe + pH in aerobic environments. The fact that most of the N2 in the atmosphere has not been converted to NO3 therefore indicates that the biological mediation of this conversion in both directions is inefficient. Hence NO3 reduction to N2 occurs by indirect mechanisms involving intermediaries. Dissimilatory reduction of N03 (i.e. where the nitrogen oxide serves as an electron acceptor for the cell s metabolism but the N reduced is not used by the microbes involved) potentially occurs by two processes denitrification. 

The first indication that Ras functions downstream from RTKs in a common signaling pathway came from experiments in which cultured fibroblast cells were induced to proliferate by treatment with a mixture of PDGF and EGF. Microinjection of anti-Ras antibodies into these cells blocked cell proliferation. Conversely, injection of Ras , a constitu-tively active mutant Ras protein that hydrolyzes GTP very inefficiently and thus persists in the active state, caused the cells to proliferate in the absence of the growth factors. These findings are consistent with studies showing that addition of FGF to fibroblasts leads to a rapid increase in the proportion of Ras present in the GTP-bound active form. 

In order to gain information about the likely mechanism of membrane transport of the 2-amino-4(377)-oxoquinazoline antifolates, Calvert et al. [45] examined the effect of varying concentrations of (III. 156) (up to 100/xM) on the accumulation of 4/xM [ H]MTX, 4/xM [ H]folate, and 4/xM pH]-methyltetrahydrofolate over 40 min by L1210 cells. Curiously, there was no inhibition of the uptake of any of these compounds by (III. 156). The authors concluded that (III. 156) might not utilize either the folate or reduced folate transport pathway, but did not indicate what alternative transport route for this compound might exist. Transport of (III. 156) via the folate carrier would seem a likely route of entry into cells, but might be inefficient in comparison with transport of the natural substrate. This would explain the inability to block the uptake of 4 xM folate even with 100 (III.156). 

The cellular levels of iron and ferrochelatase are important determinants of PpIX yield under exogenous ALA stimulation. The use of iron chelators is based on the relative inefficiency of ferrochelatase compared to other enzymes, which causes PpIX build-up when heme precursors are produced at an increased rate. In some cancer cell lines lower levels of ferrochelatase have been found than in normal cells and this may contribute to tumor selectivity in certain cancers [197]. In an attempt to further reduce or totally abrogate heme formation, exogenous chelating agents were used to remove iron. It was shown in vitro that iron chelation caused both increased PpIX formation and improved PDT efficacy and in vivo applications in animals and humans have confirmed the concept [191,198,199]. In lymphocytes that express the transferrin receptor (CD71), which is interpreted as an indication of low intracellular iron levels, higher PpIX concentrations were reached under ALA stimulation [200]. In addition, an analysis of iron availability at the molecular level... 

Chitosan microparficles provide a pofenfial system for oral vaccination. While oral vaccinations would cost less and be more comfortable than traditional injections, antigen degradation in the acidic stomach environment and unpredictable immune response at Peyer s patches render them inefficient. However, vaccines delivered in biodegradable microspheres can weather the harsh gastrointestinal environment and be phagocytized by Peyer s patch cells. Wan der Lubben et al. demonstrated that chitosan microspheres loaded with FITC labeled ovalbumin relayed their antigens to Peyer s patches. Stained intestinal epithelium showed high uptake of loaded microspheres, while pure administered FITC-ovalbumin indicated no uptake. 

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