Electrophoretic Mobility Of Red Cells Research Articles

Effects of the glycocalyx on the electrophoretic mobility of red cells and on streaming potentials in blood vessels: predictions of a structurally-based model

The polyelectrolyte layer coating mammalian cells, known as the glycocalyx, may be important in communicating flow information to the cell. In this paper, the layer is modelled as a semiinfinite, doubly periodic array of parallel charged cylinders. The electric potential and ion distributions surrounding such an array are found using the linearised Poisson-Boltzmann equation and an iterative domain decomposition technique. Similar methods are used to calculate Stokes flows, driven either by a shear at infinity or by an electric field, parallel or transverse to the cylinders. The resulting electric streaming currents due to flow over endothelial cells, and the electrophoretic mobilities of red blood cells are deduced as functions of polymer concentration and electrolyte molarity. It is shown that only the top portion of the layer is important in these effects.

Reaction of colloidal silica with membranes of intact mammalian cells

Colloidal silical particles were produced at a size that permitted reaction with human erythrocytes and rat macrophages without affecting cell integrity. Binding of colloid was shown by increased electrophoretic mobility of red cells and also resulted in changes in the surface topography of red cells as seen with scanning electron microscopy. The degree to which colloid binds to red cells was determined by microprobe analysis of single intact cells. Furthermore, the capacity of red cells to bind silica was increased if sialic acid residues were removed enzymatically from the cell surface.

Study of antigenic varieties of group A red cells, platelets and lymphocytes using liquid phase electrophoresis.

The authors attempt to study the presence of subgroups of the phenotype A on lymphocytes and platelets with the help of liquid phase electrophoresis. The results show that anti-A of B serum reduces the electrophoretic mobility of red cells, platelets and lymphocytes of group A but leaves unchanged the mobility of group O or B cells. The same variations are observed in red cell lymphocytes and platelets. The authors suppose that the distribution of antigenic sites is identical in these elements.

Surface charge on Plasmodium knowlesi and P. coatneyi-infected red cells of Macaca mulatta

Red cells infected by Plasmodium falciparum, P. coatneyi, and P. knowlesi adhere to venous endothelium. The possible role of red cell surface charge in the adhesiveness was investigated. The electrophoretic mobility of red cells from monkeys infected by P. knowlesi and P. coatneyi was not significantly different from mobilities determined before infection. When the infected red cells were concentrated by density gradient, they still showed normal electrophoretic mobility. Surface charge distribution was studied by binding positively charged ferric oxide hydrosols to glutaraldehyde-fixed red cells. Colloid binding was similar between the red cells infected with P. knowlesi and P. coatneyi and the uninfected red cells. Furthermore, knoblike membrane protrusions on red cells infected by P. coatneyi showed similar colloid binding as adjacent membranes. Therefore, neither the net surface charge nor the charge distribution on the red cell surface was altered by these infections. The knoblike protrusions in P. coatneyi-infected red cells have radii of curvature of 28–98 nm. Since these low radii would theoretically allow two similarly curved surfaces to approach within 0.5–1.0 nm of each other, knoblike protrusions may form the basis of adhesion. Knoblike protrusions of P. falciparum-infected red cells have similar dimensions and are the apparent site of attachment to venous endothelium.

Factors in the partition of red blood cells in aqueous dextran-polyethylene glycol two-phase systems

Abstract The usefulness of countercurrent distribution of cells in aqueous, buffered two-polymer phase systems is illustrated by the segregation of erythrocytes of different ages, the resolution of two populations of reticulocytes, the separability of red blood cells from white blood cells, a study of membrane characteristics of red cells from different species 1,2 . We now report the effects on erythrocyte partition of a number of factors ( e.g. I , pH, temperature, hypertonicity or hypotonicity, ABO blood group, washing of cells and anticoagulant). It is also shown how some of these parameters can be used to obtain desired partitions for (red) cells in a given investigation. In the dextran-polyethylene glycol phase systems that we have investigated, an increase in I (with constant isotonicity) appears not to alter the partition of red cells except with phosphate in which a decrease in the partition coefficient is observed. Increase in pH or temperature causes an increased partition. Different degrees of hypotonicity give similar partitions which are somewhat greater than those found in isotonic phase. Increasing hypertonicity leads to a rapid decrease in the partition coefficients. Human red cells are found to have the same partition independent of the ABO blood group to which they belong. Washing of cells or anticoagulant used (acid-citrate-dextrose, heparin, EDTA) has no effect on their partition. In view of the previously established correlation between electrophoretic mobility of red cells and their partition coefficients 3 we point out, in the course of the discussion, those instances in which the electrophoretic mobility and partition of cells are similarly affected by changing a given parameter, and those instances in which the effects are markedly different. In the latter instances partition of cells in aqueous two-polymer phase systems and electrophoretic mobility appear to measure different membrane characteristics.

The red cell electrophoretic mobility in atherosclerotic and other individuals

The surfaces of red cells possess a negative electrical charge, which will serve to maintain dispersion of the cells in blood. The electrophoretic mobility of red cells is a function of the nett negative charge (zeta potential) provided that the viscosity of the suspending medium is constant. Red cells from 50 patients with occlusive arterial disease and 50 control subjects have been suspended in their own plasma and in phosphate buffer, pH 7.35, and subjected to electrophbresis. The migration time (sec) is longer and the electrophoretic mobility ( μ /sec/V/cm) is less in the patients than in the control subjects, to a highly significant degree in plasma, and to a significant degree in buffer. The differences between the “vascular” and “control” values for electrophoretic mobility in both plasma and buffer are greater in females than in males. Collateral evidence from plasma viscosity studies suggests that the observed differences in electrophoretic mobility represent differences in the red cell surface charge (zeta potential). Patients with occlusive arterial disease therefore have one or more factors in their plasma and also on their red cells which reduce the surface charge of the cells. These factors, by facilitating red cell aggregation, may play a part in the pathogenesis of occlusive arterial disease.

Electrophoretic Mobility of Red Cells and Their Ghosts as Observed with Improved Apparatus*

ABSTRACT This paper is concerned with the application of two new techniques, both of which depend essentially on improved instrumentation, to the study of the electrophoretic mobility of red cells and their ghosts. The first technique has been developed to overcome difficulties which are encountered in the measurement of the mobility of ghosts. If the ghosts are substantially haemoglobinized, they can be seen, although with some difficulty, with the ordinary microscope and their mobility can be measured in an electrophoresis cell such as that described by Abramson (1934); if they are relatively Hb-free, on the other hand, they are almost invisible under the ordinary microscope, and can be seen satisfactorily only with phase contrast. The great majority of existing measurements of the mobility of ghosts, accordingly, are measurements of the mobility of ghosts which contain relatively large amounts of Hb. The new vertical cell to be described uses phase-contrast optics, and is fitted with removable electrodes which have several advantages over those usually employed. The second technique is the result of the observation that the Antweiler electrophoresis apparatus with a Philpot-Svensson attachment, although designed for the separation and observation of the mobilities of protein fractions, can also be used for measuring the relative mobilities of red cells and their ghosts.