The erythrocytes deformation under shear stress, the viscoelastic properties and the effects observed on healthy donors and on dyslipidemic patients are investigated from the point of view of nonlinear dynamics. Finally it is suggested that the different results obtained could be useful with regard to pathophysiological disturbances and their treatment.

This study investigates the effects produced by an increased concentration of glucose in a suspending medium on the erythrocytes Information Theory quantifiers. Erythrocytes, which were obtained from eight healthy volunteers, were washed and incubated in vitro with glucose solutions at different concentrations. The measured Wavelet-based Information Theory quantifiers include the Relative Wavelet Energy (RWE), the Normalized Total Wavelet Shannon Entropy (NTWS), MPR-Statistical Complexity Measure (SCM) and entropy-complexity plane. The results show that the increase in glucose concentration does not produce significant changes on the RWE, while significant ones on the NTSE, which combined with SCM values allow to identify different behaviour for all the different populations in the entropy-complexity plane. Modification in the hemorheological properties of cells could be clearly detected with these Wavelet-based Information Theory quantifiers.

ABSTRACT--In this work, experimental determinations are carried out using a home-made device called an erythrodeformeter, which has been developed and constructed for rheological measurements on red blood cells subjected to definite fluid shear stress. A numerical method formulated on the basis of the fractal approximation for ordinary and fractionary Brownian motion 1 is proposed to evaluate the viscoelastic behavior of mammalian erythrocyte membranes. The diffraction pattern, which is circular when the mammalian erythrocyte membranes are at rest, becomes elliptical when the cells undergo shear stress. Photometric readings of light intensity variation along the major axis of the elliptical diffraction pattern are recorded during the creep and recovery process. These data series are used to calculate fractal rheological parameters of self-affine Brownian motion on the erythrocytes, averaged over several millions of cells. Three different parameters over the time dependent process could be obtained, which are: correlation coefficient , correlation integral, and K2-entropy, and very different results were obtained.