Authors: David Szekely Tsz Wai Yau Philip W Kuchel
Publish Date: 2009/05/31
Volume: 38, Issue: 7, Pages: 923-939
Abstract
Images of human erythrocytes from a healthy donor were recorded under differential interference contrast DIC microscopy they were acquired rapidly ~336 Hz and the intensity of the centermost pixel of each cell was recorded for ~60 s 20000 values Various techniques were used to analyze the data including detrended fluctuation analysis DFA and multiscale entropy MSE however power spectrum analysis was deemed the most appropriate for metrifying and comparing results This analysis was used to compare cells from young and old populations and after perturbing normal conditions with changes in temperature adenosine triphosphate ATP concentration using NaF an inhibitor of glycolysis and αtoxin a poreforming molecule used to permeabilize red cells to ATP and water transport rates using glycerol and pchloromercuriphenylsulfonic acid pCMBS to inhibit aquaporins AQPs There were measurable differences in the membrane fluctuation characteristics in populations of young and old cells but there was no significant change in the flickering time series on changing the temperature of an individual cell by depleting it of ATP or by competing with the minor water exchange pathway via AQP3 using glycerol However pCMBS which inhibits AQP1 the major water exchange pathway inhibited flickering in all cells and yet it was restored by the membrane intercalating species dibutyl phthalate DBP We developed a computer model to simulate acquired displacement spectral time courses and to evaluate various methods of data analysis and showed how the flexibility of the membrane as defined in the model affects the flickering time course
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