scholarly journals The Uptake of Divalent Manganese Ion by Mature Normal Human Red Blood Cells

1960 ◽  
Vol 44 (2) ◽  
pp. 301-314 ◽  
Author(s):  
Robert I. Weed ◽  
Aser Rothstein
Keyword(s):  
Red Cells ◽  
Metabolic Inhibitors ◽  
Entry And Exit ◽  
Permeability Constant ◽  
Manganese Ion ◽  
Human Red Blood Cells ◽  
Metabolic Substrates ◽  
Normal Human ◽  
High Concentrations ◽  
Mn Concentration

At physiological pH and concentrations of Mn++ in excess of 5 x 10-4 M, study of the Mn++ ion movement into human red cells is complicated by physicochemical alterations of the ion itself. At concentrations below 5 x 10x4 M, the rate of uptake bears a linear relationship to the Mn++ concentration. The permeability constant for inward movement of Mn++ is 2.87 ± 0.13 (S.E.) x 10-9 cm./sec. The rate is not influenced by the addition of metabolic substrates such as glucose or adenosine or the metabolic inhibitors iodoacetate or fluoride. Co++, Ca++, and Mg++ do not appear to compete with Mn++ for entry, but at high concentrations relative to Mn++, they reduce the rate of entry. Ca++ is far more effective than Co++ or Mg++ in this regard. The permeability constant for outward Mn++ movement is 1.38 ± 0.21 (S.E.) x 10-9 cm./sec., about half of that for entry. This slower rate of outward movement is consistent with the finding that 40 to 60 per cent of the Mn++ taken up by the red cells is non-ultrafilterable. Less than 5 to 10 per cent of the Mn++ appears to be bound to the stroma. It is concluded that entry and exit of Mn++ is a process of passive diffusion involving no carriers, transport, or metabolic linkage.

Stability of nucleoside triphosphate levels in the red cells of the snake

1997 ◽  
Vol 200 (7) ◽  
pp. 1125-1131
Author(s):  
R Ingermann ◽  
D Bencic ◽  
J Herman
Keyword(s):  
Atpase Activity ◽  
Red Cells ◽  
Metabolic Inhibitors ◽  
Cell Swelling ◽  
Nucleoside Triphosphate ◽  
High Ph ◽  
High Concentrations ◽  
The Stability

Nucleated red cells in the nonpregnant garter snake (Thamnophis elegans) contain relatively high concentrations of nucleoside triphosphate (NTP), largely in the form of ATP, which is found at concentrations of approximately 10 mmol l-1 relative to cell volume and 15 mmol l-1 relative to cell water. During pregnancy, levels of NTP in adult red cells rise by approximately 50 % concomitant with an increase in blood progesterone level. The stability of the NTP pool within these red cells was assessed by maintaining cells in vitro at 20 °C, without exogenous nutrients, and in the presence and absence of the metabolic inhibitors iodoacetate and/or cyanide. After 96 h, NTP levels in adult red cells not exposed to the inhibitors had decreased by only approximately 10 %, while in the presence of both inhibitors NTP levels had fallen by less than 50 %. Red cell NTP levels were not affected by acute exposure to high concentrations of progesterone either in vivo or in vitro. NTP levels were much more labile when the cells were maintained in vitro at either low or high pH. Maintenance of red cells at pH 6.0 for 24 h resulted in a decrease in NTP levels of approximately 50 % and at pH 10.0 the levels fell by approximately 80 %, while buffers containing only ATP caused no detectable degradation. Incubation at low or high pH promoted some cell swelling; however, the magnitude of the decreases in intracellular NTP concentration prompted by these pH levels could not be mimicked by incubation of red cells in hypotonic buffer. Total nonspecific ATPase activity at pH 6.0 was approximately 55 % greater than that at pH 7.4, while at pH 10.0 it was approximately 6 % of that at pH 7.4. The pH-dependent decrease in intracellular NTP levels cannot, therefore, be due to stimulation of ATPase activity, at least not at high pH. Overall, the data are consistent with the hypothesis that an appreciable portion of the NTP within these cells is compartmentalized in a stable, but pH-sensitive, pool sequestered from intracellular ATP-hydrolyzing processes.

scholarly journals Comparison of human red cell lysis by hypochlorous and hypobromous acids: insights into the mechanism of lysis

1998 ◽  
Vol 330 (1) ◽  
pp. 131-138 ◽  
Author(s):  
C. M. Margret VISSERS ◽  
C. Anitra CARR ◽  
L. P. Anna CHAPMAN
Keyword(s):  
Membrane Protein ◽  
Protein Modification ◽  
Hypochlorous Acid ◽  
Membrane Lipids ◽  
Band 3 ◽  
Cytoskeletal Proteins ◽  
Red Cells ◽  
Fluorescent Label ◽  
Human Red Blood Cells ◽  
High Concentrations

Human red blood cells are lysed by the neutrophil-derived oxidant hypochlorous acid (HOCl), although the mechanism of lysis is unknown. Hypobromous acid (HOBr), a similarly reactive oxidant, lysed red cells approx. 10-fold faster than HOCl. Therefore we compared the effects of these oxidants on thiols, membrane lipids and proteins to determine which reactions are associated with lysis. There was no difference in the loss of reduced glutathione or membrane thiols with either oxidant, but HOBr reacted more readily with membrane lipids and proteins. Bromohydrin derivatives of phospholipids and cholesterol were seen at approx. one-tenth the level of oxidant than chlorohydrins were. However, these products were detected only with high concentrations of HOCl or HOBr, which caused instant haemolysis. Membrane protein modification occurred at much lower doses of oxidant and was more closely correlated with lysis. SDS/PAGE analysis showed that band 3, the anion transport protein, was lost at the lowest dose of HOBr and at the higher concentrations of HOCl. Labelling the red cells with eosin 5-maleimide, a fluorescent label for band 3, suggested possible clustering of this protein in oxidant-exposed cells. There was also irreversible cross-linking of all the major membrane proteins; this reaction occurred more readily with HOBr. The results indicate that membrane protein modification is the reaction responsible for HOCl-mediated lysis. These effects, and particularly cross-link formation, might result in clustering of band 3 and other membrane and cytoskeletal proteins to form haemolytic pores.

scholarly journals Kinetics and stoichiometry of Na-dependent Li transport in human red blood cells.

1978 ◽  
Vol 72 (2) ◽  
pp. 249-265 ◽  
Author(s):  
B Sarkadi ◽  
J K Alifimoff ◽  
R B Gunn ◽  
D C Tosteson
Keyword(s):  
Transport System ◽  
Red Cells ◽  
Normal Male ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Human Red Blood Cells ◽  
Na Efflux ◽  
Tightly Coupled ◽  
Male Subjects ◽  
Human Red Cells

This paper describes the kinetics and stoichiometry of a tightly coupled Na-Li exchange transport system in human red cells. The system is inhibited by phloretin and furosemide but not by ouabain. Li influx by this system increases and saturates with increasing concentrations of external Li and internal Na and is inhibited competitively by external Na. Comparable functions relate Li efflux and Na efflux to internal and external Li and Na concentrations. Analysis of these relations yields the following values for the ion concentrations required to half-maximally activate the transport system: internal Na and Li 9.0 and 0.5 mM, respectively, external Na and Li 25 and 1.5 mM, respectively. The system performs a 1:1 exchange of Na and Li moving in opposite directions across the red cell membrane. We found no evidence for a simultaneous transport of more than one Na and Li by the system. The maximum transport rate of Na-dependent Li transport varied between 0.1 and 0.37 mmol/(liter of cells X h) in the red cells of the five normal male subjects studied. No significant variations between individual subjects were observed for bicarbonate-stimulated Li transport and for the residual Li fluxes which occur in the absence of bicarbonate and in the presence of ouabain plus phloretin.

scholarly journals Absence of Rapid Exchange Component in a Low-Affinity Carrier Transport

1963 ◽  
Vol 46 (4) ◽  
pp. 721-731 ◽  
Author(s):  
Paul G. LeFevre ◽  
Keyword(s):  
Carrier Transport ◽  
Transport Model ◽  
Exchange Process ◽  
Tracer Uptake ◽  
Transport Systems ◽  
Human Red Blood Cells ◽  
Rapid Exchange ◽  
Carrier Mediated Transport ◽  
Net Uptake ◽  
High Concentrations

A previous study showed that human red blood cells equilibrate much less rapidly with D-glucose at moderately high concentrations than with C14-glucose added after the net movement is completed. This had been predicted from a simple reversible mobile-carrier mediated-transport model system suggested by the net monosaccharide transport kinetics in these cells, but is also consistent with the more complex models proposed for certain active transport systems to account for elevation of tracer fluxes of even low-affinity "substrates" when their trans-concentration is raised. The simple model predicts, however, that with any sugar showing a much lower apparent affinity for the reactive sites, such as D-ribose, this phenomenon would not be observed, and tracer equilibration should proceed at approximately the same rate as net uptake. The latter expectation was confirmed experimentally by analyses of the ribose, or radioactivity, content of washed red cells sampled serially during incubation with ribose or C14-ribose in the appropriate mixtures. The tracer ribose movement showed no evidence of a relatively rapid exchange component. The relative rapidity of glucose tracer uptake into cells preloaded with ordinary glucose may therefore more readily be attributed simply to depression of tracer efflux by competition for the saturated reactive sites, than to any action of the trans-concentration on the influx by way of a coupled exchange process.

Velocity of O2 uptake by human red blood cells

1961 ◽  
Vol 16 (3) ◽  
pp. 511-516 ◽  
Author(s):  
N. C. Staub ◽  
J. M. Bishop ◽  
R. E. Forster
Keyword(s):  
Rate Constant ◽  
Intermediate Compound ◽  
Oxygen Electrode ◽  
Theoretical Explanation ◽  
Association Rate Constant ◽  
Association Rate ◽  
Human Red Blood Cells ◽  
Hemoglobin Saturation ◽  
Uptake Process ◽  
Normal Human

We have determined the over-all association rate constant, k'c, for the uptake of oxygen by normal human erythrocytes from 0% to 97% initial hemoglobin saturation at pH 7.4 and 37óC. With a modified Hartridge-Roughton rapid-reaction apparatus, we used a small oxygen electrode to follow the oxygen uptake process rather than using the usual photocolorimetric analytical methods. The value of k'c averages 164 mm-1 sec.-1 at 0% initial saturation, rises slowly to over 300 at 50%, and then climbs rapidly to over 1500 at 95%. The theoretical explanation for the increase in k-c with rising initial oxyhemoglobin saturation is based on the increasing prominence of the fourth chemical association rate constant, k-4, in the intermediate compound theory of Adair. It is known that k-4 is several times larger than any of the other three k–s. Submitted on December 19, 1960

scholarly journals THE ROLE OF OXYGEN IN THE REGULATION OF ERYTHROPOIESIS. DEPRESSION OF THE RATE OF DELIVERY OF NEW RED CELLS TO THE BLOOD BY HIGH CONCENTRATIONS OF INSPIRED OXYGEN 12

1949 ◽  
Vol 28 (6 Pt 2) ◽  
pp. 1544-1564 ◽  
Author(s):  
John C. Tinsley ◽  
Carl V. Moore ◽  
Reubenia Dubach ◽  
Virginia Minnich ◽  
Moises Grinstein
Keyword(s):  
Red Cells ◽  
High Concentrations ◽  
Inspired Oxygen

scholarly journals The rate of the deoxygenation reaction limits myoglobin- and hemoglobin-facilitated O2 diffusion in cells

2012 ◽  
Vol 112 (9) ◽  
pp. 1466-1473 ◽  
Author(s):  
Volker Endeward
Keyword(s):  
Skeletal Muscle ◽  
Reaction Kinetics ◽  
Chemical Reaction ◽  
Diffusion Path ◽  
Red Cells ◽  
Cardiac Muscle Cells ◽  
Chemical Reaction Kinetics ◽  
Human Red Blood Cells ◽  
Intracellular Diffusion ◽  
O2 Diffusion

A mathematical model describing facilitation of O2 diffusion by the diffusion of myoglobin and hemoglobin is presented. The equations are solved numerically by a finite-difference method for the conditions as they prevail in cardiac and skeletal muscle and in red cells without major simplifications. It is demonstrated that, in the range of intracellular diffusion distances, the degree of facilitation is limited by the rate of the chemical reaction between myglobin or hemoglobin and O2. The results are presented in the form of relationships between the degree of facilitation and the length of the diffusion path on the basis of the known kinetics of the oxygenation-deoxygenation reactions. It is concluded that the limitation by reaction kinetics reduces the maximally possible facilitated oxygen diffusion in cardiomyoctes by ∼50% and in skeletal muscle fibers by ∼ 20%. For human red blood cells, a reduction of facilitated O2 diffusion by 36% is obtained in agreement with previous reports. This indicates that, especially in cardiomyocytes and red cells, chemical equilibrium between myoglobin or hemoglobin and O2 is far from being established, an assumption that previously has often been made. Although the “O2 transport function” of myoglobin in cardiac muscle cells thus is severely limited by the chemical reaction kinetics, and to a lesser extent also in skeletal muscle, it is noteworthy that the speed of release of O2 from MbO2, the “storage function,” is not limited by the reaction kinetics under physiological conditions.

Oxygen Therapeutics: Pursuit of an Alternative to the Donor Red Blood Cell

2007 ◽  
Vol 131 (5) ◽  
pp. 734-741
Author(s):  
Paul M. Ness ◽  
Melissa M. Cushing
Keyword(s):  
Blood Donation ◽  
Blood Substitute ◽  
Blood Substitutes ◽  
Red Cells ◽  
Phase Iii ◽  
Red Cell ◽  
Oxygen Carriers ◽  
Term Survival ◽  
Phase Iii Clinical Trials ◽  
Human Red Blood Cells

Abstract Context.—There is no true substitute for the many functions of human red blood cells, and synthetic products will not replace the need for blood donation in the foreseeable future. Hemoglobin-based oxygen carriers have many characteristics that would serve as a useful adjunct to red cells in clinical settings. Over time, these technologies have the potential to dramatically reshape the practice of transfusion medicine. Objective.—To review the characteristics and potential utility of hemoglobin-based oxygen carriers and perfluorocarbon-based oxygen carriers. Several hemoglobin-based oxygen carriers are under study in phase III clinical trials. Novel uses for synthetic oxygen therapeutics are emphasized. Data Sources.—All published reports with the key words oxygen therapeutics, blood substitutes, and red cell substitutes from 1933 until March 2006 were searched through Medline. Significant findings were synthesized. Conclusions.—Recognition of the true impact of red cell substitutes is still several years away. The most compelling products, hemoglobin-based oxygen carriers, have potential use in trauma, providing immediate oxygen-carrying support in the face of alloantibodies or autoantibodies, and in other clinical situations in which long-term survival of red cells is not essential. In the interim, efforts should be focused on enhancing the current blood supply system while supporting ongoing and planned blood substitute research efforts, including trials assessing novel clinical indications for these products.

Sign in / Sign up

Export Citation Format

Share Document