Annals of the New York Academy of Sciences
-
Ann. N. Y. Acad. Sci. · Jan 1983
ReviewModification of cell membrane composition by dietary lipids and its implications for atherosclerosis.
Dietary lipids can modify the properties of cell membranes, including membrane fluidity and membrane permeability. The saturation and isomerization of dietary fatty acids may affect the pattern of fatty acids acylated to glycerol in phospholipids. ⋯ The flow of calcium and other nutrients into the cells appears to be a major property affected by those changes in lipid composition of membranes and may be important in the onset of atherosclerosis. The factors that alter the character of the lipids in cell membranes should receive increased study in both in vitro and in vivo systems to clarify their role in diseases processes.
-
Animal experimental studies have shown length constants of 2-4 mm for bipolar and 8-16 mm for monopolar stimulations. Studies in models using saline-solution-filled tubes have allowed us to examine the radial and longitudinal current distribution for pseudobipolar stimulation and have demonstrated that current localization is the same for bipolar and pseudobipolar stimulation over a 6-10-dB operating range. ⋯ Experiments performed with a pseudobipolar electrode implanted into the human cochlea showed that there was significant spread of current along the ground electrode because the electrode ground impedance was significantly greater than the cochlear tissue impedances. Because this leads to less current returned at each ground electrode, the pseudobipolar array will result in less interaction for coincident stimulation.