Temperature dependence of the deformability of Carp (Cyprinus carpio) red blood cells

Summary Measurements were made of the deformability of the red cells of carp at different temperatures and compared with previous results obtained with another teleost fish (yellowtail) and human red cells. Changes with temperature are similar to those obtained with yellowtail, but interpretation of differences in terms of mean corpuscular volume alone are insufficient to account for the variations, which seem to be mainly due to differences in cellular deformability of the cells themselves.Acknowledgment. We wish to thank Karlheinz Götz for his excellent technical assistance. Reprint requests should be addressed to G.M.H.     

Do we already know how spectrin attracts ankyrin?

The interaction of ankyrin and spectrin yields the major anchor between the membrane skeleton and the lipid bilayer. It is critical for red cell deformability and stability, and it is also involved in the cellular localization of several proteins, in cell differentiation, and in neuron activity. Therefore, its nature is of great interest, and recently, several researchers have had varying degrees of success in elucidating the structural basis of ankyrin–spectrin recognition. In this short paper, we briefly summarize the data obtained and compare the resulting conclusions.     

Lack of effect of colchicine on human neutrophil chemotaxis under agarose

Summary Human polymorphonuclear neutrophil chemotaxis under agarose was assessed following in vitro treatment of cells with colchicine. No inhibition of random migration or chemotaxis was detected. The discrepancy between these results and reports utilizing micropore filter assays could be due to the need for cell deformability in the latter.Supported by a grant from the Veterans Administration and Research grant AM 19349 from the NIAMDD, NIH.     

Membrane transport of Na and K and cell dehydration in sickle erythrocytes

The cellular concentration of Hb S plays a central role in the kinetic of Hb S polymerization and cell sickling. Blood of patients with homozygous sickle cell (SS) anemia contains a variable fraction of cells which are markedly dehydrated and have increased Hb S concentration. Since a decrease in cellular Hb S concentration reduces Hb S polymerization and sickling, the study of the processes leading to sickle cell dehydration has important pathophysiological and therapeutic implications. Sickle cell dehydration is due to cellular loss of K and Cl. K loss in sickle cells can take place via either the Ca²⁺-activated K⁺ channel, or the K?Cl cotransport, or the combined effect of oxidative damage and deformation of the red cell membrane. Inhibitors of K transport through these pathways could be used to prevent dehydration of sickle cells in vivo, provided that they can be administered safely.     

Reduced deformability of erythrocytes exposed to hypercapnia.

The effect of hypercapnia on the deformability of erythrocytes was studied by means of a nuclepore membrane filter method. A decrement of the deformability by 20--40% was observed when PCO2 was increased from 50 mm Hg to 200 mm Hg, accompanied with an increment of 5% in hematocrit value.     

Red blood cell glycolysis and potassium type in sheep

Summary Based on the observations made on human and dog red blood cells, it was recently proposed that the response of red cell glycolysis to variations in the levels of specific cations is an evolutionary adaptation in response to a specific cellular environment. We have now examined the effect of K⁺ and Na⁺ on the activity of pyruvate kinase (PK) in the red blood cells from 2 genetically different types of sheep high potassium (HK) and low potassium (LK). The results indicate that K⁺ stimulate glucose consumption and the activity of PK in both types of sheep. It thus appears that red cell PK from LK sheep does not fit into the concept of cellular environment and PK activity.This work was supported by grants from the National Health and Medical Research Council of Australia, the Clive and Vera Ramaciotti New South Wales Foundation and the Helena Rubenstein Foundation, Inc.     

The negative correlation between erythrocyte concentration and mean corpuscular haemoglobin or mean corpuscular volume in normal dogs

Summary In normal adult Beagle dogs red cell concentration decreased linearly with increasing mean red cell volume and mean red cell haemoglobin. The results are statistically significant (p<0.001).     

Reduced deformability of erythrocytes exposed to hypercapnia

Summary The effect of hypercapnia on the deformability of erythrocytes was studied by means of a nuclepore membrane filter method. A decrement of the deformability by 20–40% was observed when was increased from 50 mm Hg to 200 mm Hg, accompanied with an increment of 5% in hematocrit value.     

The effect of pyrophosphate and diphosphonates on calcium transport in red cells.

The effect of 0.5 mM pyrophosphate (PPi), disodium ethane-4-hydroxy-1,1-diphosphonate (EHDP) and disodium dichloromethane diphosphonate (Cl2MDP) on the ATP-dependent Ca2+ extrusion from the human red cell ghosts was studied. PPi and Cl2MDP had no effect, when introduced into the cells or added outside to the medium. EHDP slightly increased the calcium concentration in the released cells and slightly decreased the rate constant of the calcium transport, having opposite effects when it was inside or outside the cells. PPi and the 2 diphosphonates were not found to move easily across the red cell membrane.     

The effects of two neutral polymers on the geometry and deformability of the human erythrocyte.

Polyvinylpyrrolidone and dextran decrease cellular deformability. Changes in volume do not wholly account for the changes which imply a stiffening of the plasma membrane. The effects differ from those induced by charged macromolecules.     

Diethylpyrocarbonate interferes with lipid-protein interaction and glucose transport in the human red cell membrane.

Diethylpyrocarbonate largely diminished both discontinuities in red cell glucose transport and also in red cell membrane ANS fluorescence at about 17--20 degrees C.     

The effects of parabiotic union with a normal partner on the blood tissue of the b/b rat suffering from an inheritable anemia

Summary The parabiotic union of a b/b rat, suffering from a red blood cell anemia, with a normal partner will restore to normal the functioning of this type of blood cell. The effect of parabiotic union is evident for several weeks following the separation of the parabiotic partners. It would be logical to conclude that the normal partner supplies a factor absent in the anemic animal needed for normal functioning of the red cell.     

Recombination of integral and peripheral protein fractions from human red cell membrane with homologous lipids

Summary Integral and peripheral protein fractions from human red cell membranes were recombined with a total red cell lipid extract and with homologous lipids in varying mixtures, by dialysis from 2-chlorethanol solutions. The 2 protein fractions were compared for lipid binding capacity and for selectivity towards individual lipids.     

The effects of two neutral polymers on the geometry and deformability of the human erythrocyte

Summary Polyvinylpyrrolidone and dextran decrease cellular deformability. Changes in volume do not wholly account for the changes which imply a stiffening of the plasma membrane. The effects differ from those induced by charged macromolecules.The work was supported by the Medical Research Council of Canada.     

Rheological and functional impairments in cholesterol-loaded human erythrocytes

Summary Decreased deformability, slightly increased suspension viscosity and retarded oxygen egress were observed in cholesterol-loaded, human erythrocytes. These functional changes resulted from the decreased membrane fluidity induced by cholesterol.     

Relations between magnesium, erythrocyte zinc and HL-A groups]

Red blood cell and plasma magnesium and zinc levels and plasma calcium concentrations have been determined in 84 unrelated male subjects, with known HLA groups. When the subjects are classified according to their HLA--B groups, significant variations are observed for red blood cell magnesium and zinc concentrations, while no important variation is observed for HLA--A groups. These results confirm the importance of genetic factors in the regulation of Mg and Zn red blood cell concentrations.     

Reduction of ferricytochrome c by human red cells

Summary Human red cells reduced extracellular ferricytochrome c to ferrocytochrome c under various conditions, suggesting that ferricytochrome c reducing systems are present at the outer surface of the red cell membrane.     

Reduction of ferricytochrome c by human red cells

Human red cells reduced extracellular ferricytochrome c to ferrocytochrome c under various conditions, suggesting that ferricytochrome c reducing systems are present at the outer surface of the red cell membrane.     

Diethylpyrocarbonate interferes with lipid-protein interaction and glucose transport in the human red cell membrane

Summary Diethylpyrocarbonate largely diminishes both discontinuities in red cell glucose transport and also in red cell membrane ANS fluorescence at about 17–20°C.We are very much indebted to Dr K.-H. Röhm for valuable discussions of this paper. This work was supported by the Deutsche Forschungsgemeinschaft.     

Galactose-l-phosphate uridyl transferase activity in red cells of various animal species

Summary Monkey red cells were chosen as controls in tests of human red cell galactose-l-phosphate uridyl transferase, after comparing activities and isozyme patterns of the enzyme from several domestic or laboratory-bred species.