2.9.3 Probe measurements of the two-point correlation functions2.9.4 Probe measurements of the spectrum and anomalous resistivityĢ.9.6 Microwave scattering experiments in PLTĢ.10 Drift Waves and Transport in the TEXT Tokamakģ.3 Energy Bounds for Turbulence Amplitudesģ.3.3 Drift wave eigenmodes in toroidal geometry. 2.1 Low-Frequency Wave Dispersion Relations2.2 Reduction of the Kinetic Dispersion RelationĢ.5 Coupling of the Drift Wave, Ion-Acoustic and Shear Alfven WavesĢ.6 Drift Wave Eigenmodes in a Sheared Magnetic FieldĢ.7 Symmetries of the Drift Wave EigenmodesĢ.9.1 Electromagnetic scattering measurements of ion acoustic wavesĢ.9.2 Laser scattering experiment in Helium plasma. Basic Concepts and Historical Backgroundġ.4 Magnetic Confinement Conditions for Nuclear Fusionġ.6 Breakthrough with Tokamak Confinementġ.7 Confinement Records Set in Early Tokamaksġ.7.1 First generation tokamaks: Ormak, PLT, Alcator, ATC and TFRġ.7.3 Third-generation tokamaks with international growthĢ.
These cells constitute an interesting model for the study of renal epithelial cell ageing.1. Ouabain (100 nM: ) increased alpha(1)-subunit, but not beta(1)-subunit, Na(+)/K(+)-ATPase expression in aged cells only. H(2)O(2) production was increased in aged cells, but exposure for 5 days to 1 and 10 microM: of H(2)O(2) had no effect on Na(+)/K(+)-ATPase expression.
No changes in Na(+)/H(+) exchanger activity were observed. Cell depolarization induced by both KCl and ouabain was more pronounced in aged cells. Increases in Na(+)/K(+)-ATPase activity were accompanied by increases in K(+) conductance as a result of functional coupling between Na(+)/K(+)-ATPase and basolateral K(+) channels. In vitro cell ageing is accompanied by an increase in transepithelial Na(+) transport, which results from an increase in the number of Na(+)/K(+)-ATPase alpha(1)- and beta(1)-subunits, in the membrane. Na(+)/H(+) exchanger activity, changes in membrane potential, cell viability, hydrogen peroxide production and cellular proliferation were determined using fluorimetric assays. Na(+)K(+)-ATPase alpha(1)- and beta(1)-subunit expression was quantified by Western blot techniques. Cells were aged by repeated passing, and Na(+)/K(+)-ATPase activity and K(+) conductance were evaluated using electrophysiological methods. In the present study, we examined the effect of in vitro cell ageing on the transport of Na(+) and K(+) ions in opossum kidney (OK) cells in culture. Na(+)/K(+)-ATPase plays a key role in the transport of Na(+) throughout the nephron, but ageing appears to be accompanied by changes in the regulation and localization of the pump.
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