The osmometric behavior of human erythrocytes.

A reexamination of the data of Farrant and Woolgar (Cryobiology, 9, 9–15 (1972)) demonstrates that human erythrocytes exhibit osmometric behavior as predicted from the Boyle-Van't Hoff law when suspended in sodium chloride solutions as high as 3.5 osmolal. A Boyle-Van't Hoff plot is linear with r = 0.998. However, 24% of the water in isotonic red blood cells appears to be osmotically-inactive, although nearly 75% of this apparent non-osmotic water can be accounted for by the water of hydration of hemoglobin. These facts have direct significance to hypotheses concerning hemolysis as well as to the modeling of osmometric events which occur at sub-zero temperatures.     

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.     

Effect of ion adsorption on the electrokinetic properties of erythrocytes

The microelectrophoresis technique was used to determine the dependence of human erythrocyte surface potential on the concentration of various cations and anions. The interpretation of the results is based on the Gouy--Chapman--Stern theory. Values of pK, characterizing the binding of ions to the external surface of erythrocytes, as well as numbers of binding sites per unit area were determined. The affinities of ions for the red cell membrane were shown to decrease in the sequence: H+ greater than Ca2+ greater than Sr2+ greater than Mg2+ greater than Ba2+ greater than Li+ greater than Na+ congruent to congruent to K+ congruent to NH4+ and trinitrophenol greater than IO4- greater than CIO4- greater than salicylate congruent to I- greater than greater than SCN- greater than H2PO4- greater than Br- greater than Cl- greater than HPO4(2-). Changes in the ionic strength of the medium resulted in changes in numbers of exposed ion-binding sites. This phenomenon is interpreted in terms of ionic strength-dependent structural transformations of the cell surface coat.     

Magnetic behavior of human erythrocytes at different hemoglobin states

The effect of a static magnetic field on human erythrocytes at different hemoglobin states (normal, oxidized and reduced hemoglobin) was investigated. Three different blood samples, normal, iron deficiency anemic and beta thalassemia minor, were studied. Measurements of the magnetization curves of the erythrocytes for all blood samples in all states showed diamagnetic behavior; however, oxidation was found to enhance this behavior. These measurements have also shown that the normal and iron deficiency samples in the reduced states exhibit a less diamagnetic response in comparison with the normal state. This result indicates that the reduction process gave rise to a paramagnetic component of the magnetization. Analysis of the measured paramagnetic behavior, using a Brillouin function, gave an effective magnetic moment of 8 muB per reduced hemoglobin molecule for both normal and anemic samples. This result shows that both anemic and normal blood have similar magnetic behavior and the only difference is the number of hemoglobin molecules per erythrocyte. For the beta thalassemia minor blood sample, magnetic measurements showed that both the normal and reduced states have almost the same diamagnetic behavior. However, this diamagnetic response is less than that for the normal state of the iron deficiency anemic sample. This result may indicate a low oxygen intake for the blood in the normal state for the beta thalassemia minor blood. All magnetic measurements were made using a vibrating sample magnetometer using field steps of 0.001 T from 1 T to -1 T.     

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.     

Glycosaminoglycans and electrokinetic behavior of rat ascites hepatoma cells

Cellular electrophoretic mobility of AH-130, an island-forming strain of rat ascites hepatomas, was reduced by chondroitinase-ABC treatment of cells but not affected by neuraminase. Assay of released sugars demonstrated the presence of chondroitin sulfates at the cell surface of AH-130, indicating that acidic residues of chondroitin sulfates were one of the factors responsible for negative surface charge of these cells and sialic acid was not. Surface-located chondroitin sulfates in AH-130 cells were abundant in chondroitin sulfate A. The mobility of free-cell-type subline cells was also lowered by the chondroitinase as well as by the neuraminidase, indicating the presence of chondroitin sulfates on the cell surface. The mobility of rat erythrocytes, however, was not affected by the chondroitinase.     

Theory of long-range coherence in biological systems. I. the anomalous behaviour of human erythrocytes

In this paper, an explicit expression of the interaction potential has been obtained, based on the Fröhlich model of long-range coherence in biological cells. These theoretical expressions are used to correlate with the experimental data obtained from the light scattering and the Brownian motion for the red blood cells (human erythrocytes). The necessary conditions are derived for the formation of rouleaux in human erythrocytes in the presence of long range interactions. The kinetics of rouleaux formation in terms of the properties of the diffusion coefficient has been investigated. It is concluded that both types of experimental data can be interpreted satisfactorily by this model.     

Magneto-electro-fusion of human erythrocytes

In inhomogeneous (static) magnetic fields close contact between ‘magnetic’ human erythrocytes was established. The cells were made magnetic by incubating them in a medium containing small Fe₃O₄-particles which adsorbed to the outer membrane surface. Fusion was induced by applying two electric field pulses (field strength: 8.5 kV · cm^?1; duration: 60 μs) to the magnetically collected cells. This procedure allowed the use of electrically conductive media (3 · 10^?1 Ω^?1 · cm^?1). Fusion of red blood cells occured very often. If cell suspensions of high density were used fusion resulted in the formation of giant red blood cells with osmotically intact membranes.     

Myosin from human erythrocytes

We have purified myosin from human erythrocytes using methods similar to that for other cytoplasmic myosins with a yield of about 500 micrograms/100 ml of packed cells. It consists of a 200-kDa heavy chain and light chains of 26- and 19.5 kDa and therefore differs from the isozyme in platelets which has light chains of 20- and 15 kDa. At low ionic strength, the myosin forms short bipolar filaments like those of platelet myosin. Eight of eight monoclonal antibodies to platelet myosin also bind to erythrocyte myosin. Like most myosins, it has a high ATPase activity in the presence of Ca2+ or EDTA, but is inhibited by Mg2+. Myosin light-chain kinase transfers 1 phosphate from ATP to the 20-kDa light chain, and this stimulates the actin-activated ATPase. Thus, myosin may play a role in shape changes in the erythrocytes.     

Peripheral proteins of human erythrocytes

Water soluble, nonglycosylated proteins have been extracted from human erythrocyte membranes by two different methods and characterized immunochemically and by PAGE. The spectrin peripheral protein complex (PAGE bands 1 + 2) has been equated with two antigens of intermediate mobility in immunoelectrophoretic analysis of crude spectrin developed with antiserum to bands 1 + 2 purified by elution from gels. Nonspectrin proteins, including catalase, remain in close association with isolated membranes, and display solubility properties similar to those of spectrin. Along with spectrin, they may also function in the intact cell as peripheral proteins.     

Cryopreservation of antibody-coated human erythrocytes

Standard techniques for the preservation of human erythrocytes in liquid nitrogen can be used to preserve red blood cells coated with anti-Rh₀(D) and −K antibodies. Such cells are easily recovered and appear to retain their antibody coating throughout storage and processing.     

Dielectrophoretic study of human erythrocytes

This paper is concerned with the dielectrophoretic study of human erythrocytes under cylindrical field geometry. The influence of physical variables such as the frequency and voltage of the applied electric field, conductivity of the medium in which the cells are suspended, cell concentration and exposure time of the cell to the non-uniform electric field on dielectrophoretic collection rate (DCR) is determined in a systematic manner. It is interesting to note from the DCR spectrum of human erythrocytes that the DCR is minimum at one frequency, maximum at another and there is practically no yield over a certain frequency range. This may be attributed to the variation of complex dielectric constant of the particle and medium over that frequency range. From the DCR spectrum of different groups, it is clear that DCR behaviour is different in the frequency range from 0.3–1.5 MHz, under similar conditions of temperature, conductivity and concentration of erythrocyte suspension and strength of applied AC field. The response of DCR with voltage of the applied field, concentration of cell suspension and square root of elapsed time of the cells confirms the theory of dielectrophoresis.