Electrophoretic cell separation by means of microspheres.

The electrophoretic mobility of fixed human erythrocytes immunologically labeled with poly(vinylpyridine) or poly(glutaraldehyde) microspheres was reduced by approximately 40%. This observation was utilized in preparative scale electrophoretic separations of fixed human and turkey erythrocytes, the mobilities of which under normal physiological conditions do not differ sufficiently to allow their separation by continuous flow electrophoresis. We suggest that resolution in the electrophoretic separation of cell subpopulations, currently limited by finite and often overlapping mobility distributions, may be significantly enhanced by immunospecific labeling of target populations using microspheres.     

Electrophoretic cell separation by means of microspheres

The electrophoretic mobility of fixed human erythrocytes immunologically labeled with poly(vinylpyridine) or poly(glutaraldehyde) microspheres was reduced by approximately 40%. This observation was utilized in preparative scale electrophoretic separations of fixed human and turkey erythrocytes, the mobilities of which under normal physiological conditions do not differ sufficiently to allow their separation by continuous flow electrophoresis. We suggest that resolution in the electrophoretic separation of cell subpopulations, currently limited by finite and often overlapping mobility distribution, may be significantly enhanced by immunospecific labeling of target populations using microspheres.     

An experimental test of new theoretical models for the electrokinetic properties of biological membranes. The effect of UO2++ and tetracaine on the electrophoretic mobility of bilayer membranes and human erythrocytes

For a large smooth particle with charges at the surface, the electrophoretic mobility is proportional to the zeta potential, which is related to the charge density by the Gouy-Chapman theory of the diffuse double layer. This classical model adequately describes the dependence of the electrophoretic mobility of phospholipid vesicles on charge density and salt concentration, but it is not applicable to most biological cells, for which new theoretical models have been developed. We tested these new models experimentally by measuring the effect of UO2++ on the electrophoretic mobility of model membranes and human erythrocytes in 0.15 M NaCl at pH 5. We used UO2++ for these studies because it should adsorb specifically to the bilayer surface of the erythrocyte and should not change the density of fixed charges in the glycocalyx. Our experiments demonstrate that it forms high-affinity complexes with the phosphate groups of several phospholipids in a bilayer but does not bind significantly to sialic acid residues. As observed previously, UO2++ adsorbs strongly to egg phosphatidylcholine (PC) vesicles: 0.1 mM UO2++ changes the zeta potential of PC vesicles from 0 to +40 mV. It also has a large effect on the electrophoretic mobility of vesicles formed from mixtures of PC and the negative phospholipid phosphatidylserine (PS): 0.1 mM UO2++ changes the zeta potential of PC/PS vesicles (10 mol % PS) from -13 to +37 mV. In contrast, UO2++ has only a small effect on the electrophoretic mobility of either vesicles formed from mixtures of PC and the negative ganglioside GM1 or erythrocytes: 0.1 mM UO2++ changes the apparent zeta potential of PC/GM1 vesicles (17 mol % GM1) from -11 to +5 mV and the apparent zeta potential of erythrocytes from -12 to -4 mV. The new theoretical models suggest why UO2++ has a small effect on PC/GM1 vesicles and erythrocytes. First, large groups (e.g., sugar moieties) protruding from the surface of the PC/GM1 vesicles and erythrocytes exert hydrodynamic drag. Second, charges at the surface of a particle (e.g., adsorbed UO2++) exert a smaller effect on the mobility than charges located some distance from the surface (e.g., sialic acid residues).     

Molecular forms of alkaline phosphatase of ram seminal plasma — Some properties and changes in pathological process of reproductive organs

Three molecular forms of alkaline phosphatase were isolated from ram seminal plasma. These forms, activated with Mg²⁺ ions, were characterized by very similar pH optima, K_m constant, and molecular weight. They differed in electrophoretic mobility, the latter being most probably determined by the different position of N-acetylneuraminyl groups in protein structures. Sialic acid also played a protective function for the catalytic centre.Isolated molecular forms possessed antigenic properties. Immunological serum for phosphatase proteins either inhibited or stabilized activity of alkaline phosphatase, depending on the value of the protein ratio.During experimentally induced inflammation of ram reproductive organs, a gradual decrease of the activity of alkaline phosphatase was noted, together with changes in its electrophoretic profile. This phenomenon is most likely caused by intensive synthesis of sialic acid in pathologically changed reproductive organs of the ram.     

Changes in the electrophoretic mobility of erythrocytes under the action of low-intensity pulsed magnetic field

Exposure of intact rats and human erythrocytes to low-intensity pulsed magnetic field leads to similar biphasic changes in the electrophoretic mobility of erythrocytes; this is accompanied by modification of their membrane and cytoskeletal protein spectrum.     

Effect of lipoxygenase metabolites of arachidonic acid on the surface charge of the erythrocyte membrane

The influence of metabolites of arachidonic acids on the electrophoretic mobility of the rat erythrocytes has been investigated. It is found that they can increase or decrease the surface charge of the erythrocyte membranes.     

Isolation and preliminary characterization of electrophoretic variants of copper,zinc superoxide dismutase

Summary Three electrophoretic variants of superoxide dismutase can be detected in bovine erythrocytes by gel electrophoresis and electrofocusing. The two major forms, having isoelectric points at pH 5.2 and 4.9, were isolated by preparative focusing or chromatography. No differences were found in molecular weight, metal content, antigenicity, electron spin resonance spectrum, visible and ultraviolet optical spectra. In contrast, holo- and apo-superoxide dismutase, which have an electrophoretic mobility similar to that of the two major forms, showed unresolved isoelectric points but significantly different antigenicity. This result suggests that their different electrophoretic mobility is mainly conformation-related. The variant with pl 5.2, corresponding to the protein purified by ordinary procedures, was found to be inactivated by heat treatment faster than the other form. The latter one, on the other hand, gave rise to a multiple pattern of electrophoretic bands after incubation at 75 °C.It is suggested that superoxide dismutase multiplicity in erythrocytes is not genetically determined, but may be related to segregation of subunits, made non-identically by post translational asymmetrical modification.     

Comparative electrophoretic properties of histones from trout and chicken erythrocytes and calf thymus at different concentrations of EDTA]

An introduction of EDTA into an electrophoretic system was found to cause specific changes in the histone distribution patterns. The electrophoretic mobility of histones H3, H2b and H2a from three evolutionally unrelated sources (trout and chicken erythrocytes and calf thymus) is increased and that for histones H1 and H5 is decreased with respect to histone H4. In general the decrease of electrophoretic mobility of the histones in the presence of EDTA is correlated with the content of basic amino acids in these histones. The effect observed can be used from electrophoretic analysis of histones.     

Ristomycin effect on the relationship between electrokinetic parameters of erythrocytes and their volume

It was found that a decrease in the electrophoretic mobility of erythrocytes by the action of ristomycin reflects an increase in their volume.     

Detection of Differences in Surface-charge-associated Properties of Cells by Partition in Two-polymer Aqueous Phase Systems

WHEN aqueous solutions of two polymers are mixed in certain proportions they may form two-phase systems^1,2 which can be buffered and used to partition and separate cells, particles and macromolecules by countercurrent distribution (CCD). Partition generally depends on polymer composition and concentration, the ionic composition and the charge sign of the material being partitioned. Such systems have been used to separate erythrocytes from white cells and erythrocytes on the basis of age. Changes in the surface properties of cells resulting from enzyme treatment or storage have also been demonstrated by this means³. Higher cell partition often accompanies increasing electrophoretic mobility which suggests that surface charge may be an important factor in partitioning^4–6. An apparent exception to this is the increased partition of stored human erythrocytes as compared with fresh⁷, as opposed to the mean electrophoretic mobility of both cell populations which remain identical⁸.     

Effect of La(3+) on electrophoretic mobility and aggregation of intact human erythrocytes and those treated with low concentrations of glutaric aldehyde

It was shown that the treatment of erythrocytes with low concentrations of glutaraldehyde (0.01-0.1%) for 30-120 min to a variable extent the aggregation induced by 40-330 microM La3+. The effect of glutaraldehyde on the aggregation increased with concentration and time of fixation. La3+ ions decreased to a similar extent the electrophoretic mobility of intact erythrocytes and erythrocytes treated with 0.1% glutaraldehyde. No relationship was found between the change in the negative charge on the erythrocytes and the degree of their aggregation. Neuraminidase and trypsin were shown to decrease the surface charge on the erythrocytes and the aggregation of fixed erythrocytes.     

Experimental results contradicting claimed 1009-MHz influence on erythrocyte mobility

An attempt was made to detect the influence of ultrahigh frequency radiation (1009 MHz) on the electrophoretic mobility of human erythrocytes. Ines. In contradiction to an earlier report by Ismailov no effect was observed.     

小鼠网织红细胞微观流变学特性的研究

按Bishop方法,在小鼠血液里诱导生成大量网织红细胞,然后提取网织红细胞,对其电泳率、渗透脆性、膜的流动性、细胞的变形能力和取向性进行了系统研究。研究结果表明网织红细胞在转变为成熟红细胞的短短时间内,其微观流变学特性发生了明显的变化：电泳率变小、渗透脆性变好、膜的流动性变大、细胞的变形能力变强、取向性变好,最终发育成具有全面功能的成熟红细胞。     

Effect of oxidized glutathione on some enzymes of erythrocytes and its relation to erythrocytic enzyme activity and electrophoretic mobility

1. Oxidized glutathione reacts or interacts with some erythrocytic enzymes (glucose 6-phosphate dehydrogenase, EC 1.1.1.49, aspartate aminotransferase, EC 2.6.1.10) but not with some others (lactate dehydrogenase, EC 1.1.1.27). 2. GSSG does not diminish the activity of any of these enzymes and is therefore not responsible for the decreased enzyme activities associated with older erythrocytes. 3. It may be that the reaction of aspartate aminotransferase with GSSG is the cause for the more rapid anodic electrophoretic mobility of this enzyme derived from human erythrocytes when compared with the mobility of the same enzyme from other human tissues. 4. A reinterpretation of some related, previously published, data with regard to the electrophoretic mobility of the above-mentioned enzymes from young and old erythrocytes is presented.     

Involvement of leukocytes in the regulation of erythrocyte electrokinetic properties

Factor analysis was used to study the interrelations between the electrophoretic mobility of erythrocytes and some characteristics of blood leukocytes of healthy subjects and patients with arterial hypertension. In health, the stabilization of the mean mobility of erythrocytes in the electric field was shown to be independent of the changes in the blood leukogram (mainly, owing to the redistribution in the population of the cells with different properties). In disease, the pattern of this redistribution is altered, and white blood cells are involved in the regulation of the electrokinetic parameters of erythrocytes: the latter became sensitive to the total count of leukocytes and to the counts of stab neutrophils, monocytes, and eosinophils. The mechanisms of the involvement of leukocytes in the regulation of the electrokinetic properties of erythrocytes are discussed.     

Electrophoretic mobility of human erythrocytes. On the applicability of the charged layer model.

The limitations of previous linear electrokinetic theories are discussed. A special model of the surface charge distribution, based on the minimum condition of the interfacial electrostatic free energy, is introduced. The model describes the electrophoretic mobility, taking into account the electroosmotic flow through the surface macromolecular layer and the surface conductivity. This nonlinear electrophoretic theory describes experimental data obtained with human erythrocytes. Numerical results for an uniformly distributed space charge are also presented.     

Blood middle-molecule peptides as factors in the modification of the erythrocyte membrane in burns

The electrophoretic mobility (EM) and acid stability of erythrocytes were investigated during incubation in a middle-molecule peptide-containing medium and in burns of different severity. It was shown, that EM of erythrocytes markedly increased after thermal injury. Major part of MMP fractions produced the same effect during in vitro incubation. MMP also changed the erythrocyte stability to acid haemolytic.     

Regulation of electrokinetic properties of human blood erythrocytes following exposure to emotional stressor

Using the factor analysis, we studied the influence of psychoemotional strain, experienced by students under taking examinations, on the electrophoretic mobility of their erythrocytes. Under stress condition, redistribution of shares of cells with different mobility occurs, directed to the maintenance of the optimal value of the index average level in the total pool of erythrocytes of an individual. Under stress, five factors, taken in different combinations, participate in the control of erythrokinetic properties: those of restriction of cell accumulation with abnormal mobility, and of the population quantity heterogeneity control, in addition to factors of total functional condition, emotional tension, and individual psychological steadiness of students before examination. The expression and character of stress influence on the state of erythrocyte population depend on the intensity of the functional load of the organism.     

Electrophoretic detection of reversible chlorpromazine · HCl binding at the human erythrocyte surface

The binding of chlorpromazine · HCl at the human erythrocyte surface has been detected through its effect on cellular electrophoretic mobility. Incubation of erythrocytes (approx. 5 · 10⁶/ml) in 23 μM chlorpromazine · HCl resulted in a reduction of negative electrophoretic mobility from the control value of $\text{?1.11 ± 0.01}$ (μm · s^?1)/(V · cm^?1) to $\text{?1.00 ± 0.02}$ (μm · s^?1)/(V · cm^?1) (pH 7.2, ionic strength 0.155). This mobility change was completely reversed when chlorpromazine · HCl was removed by centrifugal washing. Increasing the drug concentration to 70μM did not affect the mobility change, indicating saturation of the electrophoretically detectable drug binding sites over chlorpromazine · HCl concentration range studied here. The effect of the 23 μM chlorpromazine · HCl on electrophoretic mobility was also measured in isotonic media of reduced ionic strength. The drug-induced reduction in negative surface charge density was found to be independent of ionic strength over the range 0.155 (Debye length, 0.8 nm) to 0.00310 (Debye length, 5.7 nm).Fixation of erythrocytes with glutaraldehyde affected neither the normal electrophoretic mobility of discocytes nor the reduced electrophoretic mobility of chlorpromazine · HCl-induced stomatocytes. When these stomatocytes were first fixed with glutaraldehyde, then washed free of chlorpromazine · HCl, they retained the stomatocyte form while regaining a normal control electrophoretic mobility. Conversely, when discocytes fixed in that form were treated with chlorpromazine · HCl, they showed the same mobility change as did fixed or unfixed stomatocytes. The drug-induced mobility change is therefore independent of the shape change, but reflects a contribution to cellular surface charge density from the membrane-bound chlorpromazine · HCl molecules. From the charge reduction, it is estimated that about 10⁶ chlorpromazine · HCl molecules are bound at the electrokinetic cell surface and occupy approximately 0.4% of the total surface area.     

The effect of neuraminidase on the relative surface charge-associated properties of rat red blood cells of different ages

Approx. 70% of the sialic acid on the rat erythrocyte surface is susceptible to cleavage by neuraminidase (Vibrio cholerae). Neuraminidase treatment results in a reduction in the partition coefficient (K) of the red cells in a charged dextran-poly(ethylene glycol) aqueous phase system and in the electrophoretic mobility of the cells. Countercurrent distribution of rat neuraminidase-treated erythrocytes, containing 59Fe-labeled mature red cells of distinct age, indicates that (a) the electrophoretic mobilities of red cells in different cavities along the extraction train increase with increasing K, as is the case with untreated erythrocytes, and (b) the cell age-related differences in surface charge-associated properties are neither eliminated nor altered by the enzyme action.