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The effects of nonionic polymers on human red blood cell (RBC) aggregation were investigated. The hydrodynamic radius (Rh) of individual samples of dextran, polyvinylpyrrolidone, and polyoxyethylene over a range of molecular weights (1,500-2,000,000) were calculated from their intrinsic viscosities using the Einstein viscosity relation and directly measured(More)
Blood is a two-phase suspension of formed elements (i.e., red blood cells [RBCs], white blood cells [WBCs], platelets) suspended in an aqueous solution of organic molecules, proteins, and salts called plasma. The apparent viscosity of blood depends on the existing shear forces (i.e., blood behaves as a non-Newtonian fluid) and is determined by hematocrit,(More)
Polymer-induced red blood cell (RBC) aggregation is of current basic science and clinical interest, and a depletion-mediated model for this phenomenon has been suggested; to date, however, analytical approaches to this model are lacking. An approach is thus described for calculating the interaction energy between RBC in polymer solutions. The model combines(More)
The microcirculatory disturbances in sepsis have prompted micropore bulk-filtration studies of red blood cell (RBC) mechanical behavior (i.e., deformability). However, these prior reports may not solely reflect RBC behavior because of possible white blood cell (WBC) occlusion of the filter pores. The present study was designed to examine RBC mechanical(More)
To assess the influence of intracellular hemoglobin concentration on red cell viscoelasticity and to better understand changes related to in vivo aging, membrane shear elastic moduli (mu) and time constants for cell shape recovery (tc) were measured for age-fractionated human erythrocytes and derived ghosts. Time constants were also measured for osmotically(More)
A novel experimental approach based on electrical properties of red blood cell (RBC) suspensions was applied to study the effects of the size and morphology of RBC aggregates on the transient cross-stream hematocrit distribution in suspensions flowing through a square cross-section flow channel. The information about the effective size of RBC aggregates and(More)
Activated leukocytes can affect adjacent cells by generating oxygen free radicals and secreting proteolytic enzymes, and red blood cells (RBC) exposed to such agents should be susceptible to their effects. This study was thus designed to investigate the effects of activated polymorphonuclear leukocytes (PMN) on RBC aggregability (i.e., on intrinsic RBC(More)
Horse blood has a higher tendency to form red blood cell (RBC) aggregates compared with human blood, with this enhanced aggregation previously attributed to differences in plasma factors. Our results confirm this observation and further indicate that washed horse RBC also have a significantly higher aggregation tendency in dextran 70 solutions (i.e., horse(More)
Measurement of red blood cell (RBC) deformability by ektacytometry yields a set of elongation indexes (EI) measured at various shear stresses (SS) presented as SS-EI curves, or tabulated data. These are useful for detailed analysis, but may not be appropriate when a simple comparison of a global parameter between groups is required. Based on the(More)
Low-shear viscometry is one of the methods commonly used to estimate the degree of red blood cell (RBC) aggregation in various bloods and RBC suspensions. However, it has been previously shown that alterations in RBC morphology and mechanical behavior can affect the low-shear apparent viscosity of RBC suspensions; RBC aggregation is also sensitive to these(More)