Studies on the osmotic resistance and the viability of amidinated erythrocytes]

The present studies are concerned with properties of amidinated erythrocytes. The reactions of dimethyladipimidate with proteins in solution and red blood cells, respectively, result in an intermolecular cross-linking. Following an amidination of human serum albumin or human gamma-globulin cross-linked products of increased molecular weight have been demonstrated by polyacrylamide gel and immune electrophoresis. Human erythrocytes previously amidinated intensely, exhibit a restricted motility of membrane particles and cross-linked hemoglobin. Intensely amidinated erythrocytes are resistant against distilled water, and they do no longer agglutinate. The findings presumably indicate an increased permeability of the amidinated red cell membrane. The glycolytic activity was found to be normal in moderately amidinated erythrocytes. In comparison with normal red blood cells, previously moderately amidinated erythrocytes of the rat become sequestered more quickly after re-injection into the vascular system.     

Intravital survival and deformability of weakly amidinated rat erythrocytes]

Rat erythrocytes previously labelled with 51Cr were treated with 0.1 mM and 0.5 mM dimethyladipic imidate (ADE) pH 9.5, respectively, or with borate buffer pH 9.5 for 15 minutes each. After reinjection into rats of amidinated or nonamidinated erythrocytes their elimination form the streaming blood was followed for 50 days (0.1 mM ADE) or 38 days (0.5 mM ADE). During the 1st day about 10% of amidinated erythrocytes were sequestered. There was no increased initial elimination rate of borate incubated red blood cells detectable. During the following period the elimination rate of erythrocytes amidinated with 0.5 mM ADE was slightly greater than in the case of erythrocytes treated with 0.1 mM ADE. The mean life span of 0.5 mM ADE-erythrocytes was shorter compared with the controls and with 0.1 mM ADE-erythrocytes. Red blood cells previously treated with 0.5 mM ADE are significantly less deformable. Presumably, the stiffness of amidinated erythrocytes causes their increased elimination rate.     

The possibility of use of amidinated human erythrocytes as agglutinin adsorbents in hemagglutination tests]

This study is concerned with the agglutinability of amidinated human erythrocytes. Amidinated erythrocytes behave like an immuno-adsorbent. Following the adsorption of an agglutinin, amidinated erythrocytes agglutinate specifically with native red blood cells or with native eukaryotic cells, if the glycocalyx of these native cells is provided with the respective agglutinin receptor groupings.     

Mechanical lysis of human erythrocytes. Membrane stabilization by plasma proteins]

Mechanical properties of erythrocyte membranes play an important role in red cell functions. Stability of human erythrocytes under deforming mechanical tensions which occur in the rapidly moving fluid is studied. The activation energy of the mechanical hemolysis determined by the temperature dependence of the hemolysis rate is 55 + 7 kJ/mol. The fragility of erythrocytes rises sharply as the salt concentrations increase. Glutaric dialdehyde forms a certain number of interprotein bonds which increase the fragility of erythrocytes. The mechanical stability of the erythrocyte membrane falls at high (0.5 M) ethanol concentrations. Blood plasma proteins, particularly human serum albumin, have a pronounced stabilizing effect. The hemolysis occurring during the rapid mixing is not probably associated with an osmotic mechanism since high sucrose concentrations do not prevent this process. The mechanical hemolysis depends both on the deforming tension arising in the membrane and on the state of the erythrocyte membrane.     

Acetylcholinesterase in aging of human erythrocytes]

Acetylcholinesterase possessed a different activity in the membranes of young, mature and old human erythrocytes - it was greatest in the mature and least in the old cells. In the young and mature erythrocytes the enzyme existed in the form of 3- and in the old ones in the form of 2-molecular components. The data obtained suggested that the changes in the structural organization of acetylcholinesterase in the red cell membrane had a direct relationship to the aging of these cells.     

Antihemolytic effect of various benzodiazepines on human erythrocytes]

The benzodiazepines, medazepam, chlorodiazepoxyde, and oxazepam, act antihemolytically just as chloropromazine in hypotonic NaCl solution on human erythrocytes. The effect depends on concentration and is biphasic with the exception of oxazepam. The maximal antihemolytic concentrations are for medazepam 9.1-10-5 M, for chlorodiazepoxyde 4.6-10-4 M and, respectively, 9.1-10-4 M for diazepam and oxazepam. No linear correlation exists between the concentration at maximal hemolytic protection and the lipid solubility.     

Temperature dependence of the sedimentation velocity of human erythrocytes]

The sedimentation velocity of yeast cells and human erythrocytes as a function of temperature was studied in a range from 6 degrees C to 40 degrees C. Whereas this function for yeast cells can be described by an exponential function the measurements with erythorcytes show minima at 10 degrees C and 20 degrees C, respectively, and maxima at 13 degrees C and 38 degrees C. Changes of the density or the shape of the cells cannot be the reason for these effects. Viscosity measurements on erythrocyte suspensions as a function of temperature also show deviations from the exponential function between 18 degrees C and 24 degrees C. The results explain that alterations of the membrane viscosity and phase transitions of the membrane lipids influence the sedimentation velocity of erythrocytes.     

Variability of biological glucose transport activity in human erythrocytes]

Glucose transport activity was determined on erythrocytes from healthy adult and children. A large variability of values was found between each donor, but transport rate was significantly higher in erythrocytes from adults than those from children. In opposite, the same number of glucose transport sites was found on erythrocytes from adult and children, suggesting that transporters from adult erythrocytes exhibited an higher own activity than transporters from child erythrocytes. Involvement of various factors in glucose transport activity was discussed.     

Phenomenon of human peripheral blood lymphocyte interaction with autologous erythrocytes]

Phenomenon of the lymphocyte interaction with autologous erythrocytes was revealed in the patients with auto-immune diseases. Macroscopically this phenomenon appeared in the form of hemagglutination, and microscopically--of "rosette" formation. No lymphocyte interaction with autologous erythrocytes was found in the group of normal subjects and patients without autoimmune disorders.     

Effect of rhenium complexes with organic ligands on acid resistance of human erythrocytes

The authors showed stabilizing effect of rhenium binuclear cluster compounds with organic ligands on erythrocytic membranes. Estimation of functional condition of cells was studied by a chemical fragility method. Biphase type of rhenium complexes concentration curves stabilization has been found out; the influence of organic radicals and axial substructures (Cl- and Br-) on degree of stabilization has been showed. Different mechanisms of interaction of the investigated complexes with erythrocytic are suggested.     

The entrapment of [14C]ascorbic acid in human erythrocytes

Radioactively labelled ascorbic acid and dehydroascorbic acid, when incubated with human blood, migrate irreversibly into human red blood cells. Isolation and characterization of the moieties trapped within the cells via infrared spectroscopy established both their identities as L-ascorbic acid. Evidence in the form of the degree of in vitro entrapment of ascorbic acid as a function of the times of incubation and the effect of incubation temperature, anion recognition site inhibitor, and active transport inhibitor on the rate of entrapment support the hypothesis that ascorbic acid is oxidized on or near the surface of the red blood cell to dehydroascorbic acid which migrates through the lipid portion of the cell wall and is reduced back to ascorbic acid within the cell. The resulting L-ascorbic acid can not pass through the cell wall and is therefore entrapped.     

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.