Effect of some monovalent anions on chloride and sulphate permeability of human red cells

1. The permeability of human red cells to (36)Cl(-) and to [(35)S]SO(4) (2-) was studied in the presence of various monovalent anions.2. A maximum decrease of anion permeability was found in a study of the steady-state exchange of (36)Cl in a medium containing 120 mM salicylate. The exchange had a half-time of 3 hr at 0 degrees C, a reduction of normal chloride permeability by a factor of 10(5). The activation energy of chloride exchange decreased from a value of 45 to 22 kcal/mole in the interval between 0 and 10 degrees C. Simultaneous determination of the permeability to potassium and chloride proved that salicylate induced a reversal of the normal selectivity of red cells at 0 degrees C (permeability coefficient P(K) of 3.5 x 10(-9) cm/sec to be compared with a P(Cl) of 2 x 10(-9) cm/sec).3. In contradistinction to the slow movement of (36)Cl, the exchange of [(14)C]salicylate was completed within 4 min, when red cells were suspended at 0 degrees C in the salicylate medium.4. A study of the sulphate permeability at 38 degrees C showed that the rate of steady-state exchange decreased, when chloride was replaced by lyotropic anions other than bromide. The sequence of the permeability decrease was: Cl(-) = Br(-) < I(-) < NO(3) < SCN(-) < salicylate, the same sequence which previously has been shown to increase the permeability to sodium and potassium. The activation energies of sulphate exchange were 32 kcal/mole (chloride medium), and 38 kcal/mole (thiocyanate medium).5. Sufficient data were obtained during the study to demonstrate that when equilibrium has been obtained, there is a good agreement between the values of (36)Cl (cell water)/(36)Cl (extracellular water) and of {[(35)S]SO(4) (cell water)/[(35)S]SO(4) (extracellular water)}((1/2)).6. It is concluded that the anion-induced changes of permeability are due to binding of anions to fixed cationic charges in the red cell membrane.     

Effects of the medium on the filterability of human red blood cells

Red blood cell filterability as an appropriate method for evaluating red blood cell deformability was studied with different suspending media of erythrocytes. Comparison of autologous plasma and buffer suspensions of healthy subjects' erythrocytes showed no significant difference in filterability. Albumin alone resulted in a dose-dependent increase, while fibrinogen caused a decrease in red cell filterability. In the presence of fibrinogen, albumin showed controversial effects. The results suggest that measurements of red blood cells in their original surroundings give more accurate information about the microcirculation because plasma components may have a crucial influence on erythrocyte deformability.     

The asymmetry of the facilitated transfer system for hexoses in human red cells and the simple kinetics of a two component model

1. 4, 6-O-Ethylidene-alpha-D-glucopyranose (ethylidene glucose) has been used to study the competitive inhibition of glucose exchange fluxes when the reagent was (i) inside the cells and (ii) on the outside.2. 50% inhibition of glucose exchange at 20 mM and 16 degrees C required 200 mM ethylidene glucose when on the inside in contrast to 25-30 mM when on the outside.3. The inhibitions at different inhibitor/glucose concentration ratios were measured and analysis of the data suggested that the half-saturation constant for ethylidene glucose was 6 times that for glucose inside the cell as against 1.5 outside. The analysis, however, suggested an asymmetry in respect to the affinities for glucose of approximately ten-fold and this would make the asymmetry towards ethylidene glucose forty-fold.4. Such asymmetries make it necessary to consider a transfer mechanism for sugars with different components on the outer and inner membrane interfaces and simple kinetics for a two component system have been developed and used for analysing the experimental data quantitatively.5. The kinetic similarities to and difference from the kinetics of a simple mobile carrier and those of some more recent models are briefly discussed.     

Effects of obstructive jaundice on the antioxidative capacity of human red blood cells

Transient haemolysis and shortened erythrocyte lifespan are reported in association with extrahepatic biliary tract obstruction. An increase in lipid peroxidation has been noted as evidence of oxidative damage in red cells due to cholestasis. The influence of surgical relief on the antioxidative capacity of the erythrocyte is less well defined. The ability of erythrocytes to regenerate the antioxidative capacity after side-to-side choledo-choduodenostomy was assessed by measuring the two principal antioxidant enzymes, namely superoxide dismutase (SOD) and catalase (CAT), as well as the glutathione (GSH) content in the red blood cells (RBC) taken from patients with obstructive jaundice. A comparison of patients and healthy volunteers revealed a consistent decrease in enzyme activities (pSOD = 0.01, pCAT = 0.0002) and glutathione concentrations (PGSH = 0.0000) in cholestatic patients. Statistical analysis proved a clear correlation between the surgical relief of common bile duct obstruction and restored antioxidative capacity of red cells. These observations suggest that the red cells from patients with multiple common bile duct stones almost completely regenerated their antioxidative capacity four weeks after side-to-side choledochoduodenostomy.     

Sodium and potassium permeability of red blood cells in dependence of the pH

Summary In rabbit red cells, it has been found that the permeability to sodium and potassium ions depends on the hydrogen ion concentration.The sodium and potassium net flux showed maxima at distinctly different pH-values: sodium at pH 6.6, and potassium at pH 7.0.Studies with radioisotopes indicated that the pH-dependent maxima of thenet fluxes were due to an increase of thedownhill movement of sodium and potassium ions. The uphill movement, in contrast to the downhill movement, was little influenced by the hydrogen ion concentration.The downhill movement as well as the uphill movement haveQ ₁₀-values of more than 2.0.The potassium influxmeasured under the influence of ouabain is in close agreement to the influxcalculated by means of the efflux rates and the concentration gradients.In order to explain the changes in permeability, a hypothesis has been developed assuming that structural elements of the membrane with ampholytic properties such as proteins and phosphatides are responsible for the change in permeability caused by variations in the hydrogen ion concentration.

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Zusammenfassung Die Durchlässigkeit von Kaninchenerythrocyten für Natrium-bzw. Kaliumionen ist in hohem Maße von der Wasserstoffionenkonzentration abhängig.Sowohl der Natrium- als auch der Kalium-Nettoflux zeigen ein Maximum, aber bei unterschiedlichen pH-Werten: Natrium bei pH 6,6 und Kalium bei pH 7,0.Untersuchungen mit Radioisotopen ergaben, daß die für den Nettoflux gefundenen Maxima vorwiegend auf einer Beeinflussung der Bergabbewegung beruhen. Die Abhängigkeit der Bergaufbewegung von der Wasserstoffionenkonzentration ist im Gegensatz zur Bergabbewegung gering.Sowohl die Bergauf- als auch die Bergabbewegung von Kalium und Natrium sind stark temperaturabhängig und haben einenQ ₁₀-Wert über 2,0.Der unter Ouabaingemessene Kaliuminflux stimmt sowohl hinsichtlich der pH-Abhängigkeit als auch des Ausmaßes mit dem aus den Effluxraten und den Konzentrationsgradientenerrechneten Kaliuminflux gut überein.Die Diskussion der Befunde geht von der Vorstellung aus, daß Strukturelemente der Erythrocytenmembran mit ampholytischem Charakter, wie Proteine und Phosphatide, für die durch Wasserstoffionen hervorgerufenen Änderungen des Natrium- bzw. Kaliumfluxes verantwortlich sind.

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A report based on these results was given at the joint meeting of the Swiss and German Societies of Biochemists in Oct. 1960, Zürich, Switzerland.     

内生致冷原对人红细胞膜通透性的影响

本实验观察了ＥＣ对人红细胞膜血红蛋白及钾离子通透性的影响。结果显示，在温度升高（４１℃）或长时间培养（７０ｈ）的情况下。ＥＣ能有效地防止血红蛋白的漏出，但ＥＣ不能防止钾的透出。说明ＥＣ可能参与细胞膜对大分子通透性的调节。     

The ultrastructure of human red cells

Summary Forms with defects of various degrees were discovered in an electronic-microscopic study of the erythrocytic stroma obtained by osmotic hemolysis. These forms can not be split into individual groups (as it was done by Gol'din), since they are transitionally linked with each other.Presented by Active Member AMN SSSR N. N. Zhukov-Verezhnikov     

Thallium and the sodium pump in human red cells

1. Thallium (Tl) inhibits the ouabain-sensitive K influx in human red cells in high-Na medium. At 1 mM external K concentration [K(o)], the ouabain-sensitive K influx decreases steadily with increasing Tl concentration, up to 0.9 mM outside; at 0.17 mM-K(o), however, Tl stimulates the ouabain-sensitive K influx below 0.1 mM-Tl(o) and inhibits it at higher concentrations.2. In a K-free medium in which all except 5 mM-Na is replaced by choline, and into which red cells show zero control ouabain-sensitive Na efflux, Tl is able to support ouabain-sensitive Na efflux up to 2.1 m-mole/l. cells.hr following a sigmoid activation curve which is half-maximal between 0.03 and 0.05 mM-Tl(o) and that follows two-site kinetics up to 0.1 mM-Tl(o). Beyond 0.15 mM-Tl(o), the Tl-activated ouabain-sensitive Na efflux attained is inhibited slightly.3. When the ouabain-sensitive Na efflux is measured at 5 mM-Na(o) and 5 mM-K(o), increasing concentrations of Tl have little effect on it, 0.9 mM-Tl(o) inhibiting by some 14%; in similar conditions, the ouabain-sensitive K influx is inhibited by about 40%.4. The dependence of ouabain-sensitive K influx on external K concentration at 5 mM-Na(o), which follows a slightly sigmoid curve in the absence of Tl, changes to hyperbolic at 0.06 mM-Tl(o) at the same time that ouabain-sensitive K influx is inhibited. The fitted V(max) values for ouabain-sensitive K influx are the same in the presence and in the absence of 0.06 mM-Tl(o).5. In high-Na cells, loaded by nystatin treatment, the ouabain-sensitive K influx measured at 0.2 mM-Na(o) follows a hyperbolic curve between 0.05 and 0.4 mM-K(o), and is inhibited by Tl in a strictly competitive fashion.6. The effects of Tl on ouabain-sensitive Na efflux and ouabain-sensitive K influx are interpreted in terms of a high-affinity substitution for K at the external K sites of the Na pump and suggest that in human red cells Tl can be actively transported inwards in exchange for internal Na.7. Thallium can inhibit about 25% of the ouabain-insensitive Na efflux into 5 mM-Na(o) and part of this inhibition occurs with a high Tl-affinity; the ouabain-insensitive K influx is inhibited by Tl both in high-Na and in 5 mM-Na medium, but with a different concentration dependence than the ouabain-insensitive Na efflux.     

Action of some foreign cations and anions on the chloride permeability of frog muscle

1. Evidence for the existence in skeletal muscle of a specific cation binding system capable of lowering the chloride permeability was obtained by testing the effect of several metal ion species upon the efflux of (36)Cl from frog muscles equilibrated in high-KCl solution.2. Cu(2+), Zn(2+) and UO(2) (2+) ions, when present in concentrations of approximately 10(-4)M in inactive wash solution at pH 7.4 slowed the efflux of (36)Cl to half its original value. At pH 5.0, when the chloride permeability was already low as a consequence of hydrogen ion binding, these metal ions had little further effect.3. Presence of Ni(2+), Co(2+), Pb(2+), Ce(3+) and La(3+) in 10(-4)M or higher concentrations had no detectable influence on the (36)Cl efflux. Wide variations in Ca(2+) concentration were similarly ineffective.4. The influence of more adsorbable anions on the chloride permeability was examined at different pH values. Extracellular iodide greatly slowed the rapid efflux of (36)Cl into alkaline solution. In acid solutions, when the chloride permeability was already low, the effect of iodide was less pronounced, but still demonstrable. The chloride permeability was consequently increased to a lesser extent by a rise in pH in the presence of iodide.5. The efflux of iodide and bromide was measured at different pH values under conditions of self exchange. In alkaline solution the permeabilities to iodide and bromide were considerably lower than that to chloride. In acid solution the membrane differentiated less between anion species of different adsorbability.