The effect of ascorbic acid on nitrite-induced methemoglobin formation in rats, sheep, and normal human erythrocytes

1983 ◽  
Vol 3 (3) ◽  
pp. 184-188 ◽  
Author(s):  
Edward J. Calabrese ◽  
Gary S. Moore ◽  
Mark S. McCarthy
Keyword(s):  
Ascorbic Acid ◽  
Human Erythrocytes ◽  
Normal Human ◽  
Methemoglobin Formation

scholarly journals The complex of phosphatidylinositol 4,5-bisphosphate and calcium ions is not responsible for Ca(2+)-induced loss of phospholipid asymmetry in the human erythrocyte: a study in Scott syndrome, a disorder of calcium- induced phospholipid scrambling

Blood ◽  
1995 ◽  
Vol 86 (5) ◽  
pp. 1983-1991 ◽  
Author(s):  
EM Bevers ◽  
T Wiedmer ◽  
P Comfurius ◽  
J Zhao ◽  
EF Smeets ◽  
...  
Keyword(s):  
Lipid Vesicles ◽  
Human Erythrocytes ◽  
Mechanism Analysis ◽  
Membrane Phospholipids ◽  
Mole Percent ◽  
Cellular Processes ◽  
Phospholipid Asymmetry ◽  
Dependent Cell ◽  
Normal Human ◽  
State Concentration

Elevation of cytoplasmic Ca2+ levels in human erythrocytes induces a progressive loss of membrane phospholipid asymmetry, a process that is impaired in erythrocytes from a patient with Scott syndrome. We show here that porcine erythrocytes are similarly incapable of Ca(2+)- induced redistribution of membrane phospholipids. Because a complex of phosphatidylinositol 4,5-bisphosphate (PIP2) and Ca2+ has been proposed as the mediator of enhanced transbilayer movement of lipids (J Biol Chem 269:6347,1994), these cell systems offer a unique opportunity for testing this mechanism. Analysis of both total PIP2 content and the metabolic-resistant pool of PIP2 that remains after incubation with Ca2+ ionophore showed no appreciable differences between normal and Scott erythrocytes. Moreover, porcine erythrocytes were found to have slightly higher levels of both total and metabolic-resistant PIP2 in comparison with normal human erythrocytes. Although loading of normal erythrocytes with exogenously added PIP2 gave rise to a Ca(2+)-induced increase in prothrombinase activity and apparent transbilayer movement of nitrobenzoxadiazolyl (NBD)-phospholipids, these PIP2-loaded cells were also found to undergo progressive Ca(2+)-dependent cell lysis, which seriously hampers interpretation of these data. Moreover, loading Scott cells with PIP2 did not abolish their impaired lipid scrambling, even in the presence of a Ca(2+)-ionophore. Finally, artificial lipid vesicles containing no PIP2 or 1 mole percent of PIP2 were indistinguishable with respect to transbilayer movement of NBD- phosphatidylcholine in the presence of Ca2+. Our findings suggest that Ca(2+)-induced redistribution of membrane phospholipids cannot simply be attributed to the steady-state concentration of PIP2, and imply that such lipid movement is regulated by other cellular processes.

Anaerobic Glycolysis in Normal Human Erythrocytes Incubated in Vitro with Sodium Salicylate

1975 ◽  
Vol 49 (5) ◽  
pp. 375-384
Author(s):  
N. Worathumrong ◽  
A. J. Grimes
Keyword(s):  
Sodium Salicylate ◽  
Lactate Production ◽  
Glucose Consumption ◽  
Human Erythrocytes ◽  
Anaerobic Glycolysis ◽  
Initial Stimulus ◽  
Sodium Efflux ◽  
Normal Human ◽  
Concentration Changes

1. Some effects of sodium salicylate upon anaerobic glycolysis have been studied in normal human erythrocytes incubated for up to 6 h at 37°C in autologous sera. 2. Both glucose consumption and lactate production were stimulated by concentrations of salicylate up to 60 mmol/l but at the highest concentration used (90 mmol/l) an initial stimulus was followed by inhibition of glycolysis. 3. Losses occurred of adenosine 5′-triphosphate (ATP), adenosine 5′-diphosphate (ADP) and adenosine 5′-phosphate (AMP) at higher concentrations of salicylate and there was a concomitant increase of inorganic phosphate. 4. Other phosphate esters underwent concentration changes at higher concentrations of salicylate that reflected inadequate concentrations of ATP for glycolysis. 5. The rates of sodium efflux from, and potassium influx into, erythrocytes were unaffected by the presence of salicylate at concentrations sufficient to stimulate glycolysis.

Crocin protects human erythrocytes from nitrite-induced methemoglobin formation and oxidative damage

2016 ◽  
Vol 40 (12) ◽  
pp. 1320-1331 ◽  
Author(s):  
Fariheen Aisha Ansari ◽  
Shaikh Nisar Ali ◽  
Riaz Mahmood
Keyword(s):  
Oxidative Damage ◽  
Human Erythrocytes ◽  
Methemoglobin Formation

Cell volume, K transport, and cell density in human erythrocytes

1987 ◽  
Vol 252 (3) ◽  
pp. C269-C276 ◽  
Author(s):  
C. Brugnara ◽  
D. C. Tosteson
Keyword(s):  
Cell Volume ◽  
Cell Density ◽  
Human Erythrocytes ◽  
Ph Optimum ◽  
Cation Content ◽  
Original Volume ◽  
Dense Fraction ◽  
Normal Human ◽  
K Transport ◽  
Hypotonic Swelling

We report here studies on the regulation of cell volume and K transport in human erythrocytes separated according to density. When cell volume was increased (isosmotic swelling, nystatin technique), erythrocytes of the least dense but not of the densest fraction shrunk back toward their original volume. This process was due to a ouabain (0.1 mM) and bumetanide (0.01 mM) (OB)-resistant K loss. OB-resistant K+ efflux from the least dense fraction was stimulated by hypotonic swelling and had a bell-shaped dependence on pH (pH optimum 6.75–7.0). These pH and volume effects were not evident in the densest fraction. The swelling-induced K+ efflux from the least dense fraction was inhibited when chloride was substituted by nitrate, thiocyanate, and acetate, whereas it was stimulated by bromide. Increasing cell Mg2+ content also markedly inhibited K+ efflux from isosmotically swollen cells. N-ethylmaleimide (NEM, 1 mM) greatly increased OB-resistant K+ efflux from the least dense fraction but not from the densest fraction. These data reveal the presence, in the lease dense fraction of normal human erythrocytes, of a pathway for K+ transport that is dependent on volume, pH, and chloride, is inhibited by internal Mg2+, and possibly plays a role in determining the erythrocyte water and cation content.

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