scholarly journals The effect of the red cell membrane and a diffusion boundary layer on the rate of oxygen uptake by human erythrocytes

1981 ◽  
Vol 316 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Virginia H. Huxley ◽  
Howard Kutchai
Keyword(s):  
Boundary Layer ◽  
Cell Membrane ◽  
Oxygen Uptake ◽  
Human Erythrocytes ◽  
Diffusion Boundary Layer ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Diffusion Boundary

scholarly journals Diminished osmotic fragility of human erythrocytes following the membrane insertion of oxygenated sterol compounds

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 317-325
Author(s):  
RA Streuli ◽  
JR Kanofsky ◽  
RB Gunn ◽  
S Yachnin
Keyword(s):  
Cell Membrane ◽  
Hereditary Spherocytosis ◽  
Osmotic Fragility ◽  
Human Erythrocytes ◽  
Fragility Curve ◽  
Membrane Insertion ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Mean Cell Volume ◽  
Osmotic Lysis

Oxygenated sterol compounds (OSC), when incubated for 1 hr with human erythrocytes in lipoprotein-depleted medium at concentrations of 0.625- 5 X 10(-5) M, are inserted into the cell membrane and remain there despite subsequent washing of the cells. The insertion results in expansion of the surface area of the red cell ghost membrane, an increase in critical hemolytic volume, and as a consequence, in diminished osmotic fragility of the erythrocytes. This effect is seen with echinocyte-forming as well as with non-echinocyte-forming OSC. Erythrocytes treated with OSC do not differ from control cells with respect to their mean cell volume (MCV) in isotonic solution, water content, ion fluxes, and filterability through polycarbonate filters. The shift of the osmotic fragility curve toward lower NaCl concentrations is proportional to the amount of OSC inserted into the red cell membrane. 7 beta-Hydroxycholesterol, 22-ketocholesterol, and 20 alpha-hydroxycholesterol are the most potent inhibitors of osmotic lysis. The effect of OSC on osmotic fragility is diminished if the erythrocytes are incubated in a lipoprotein-containing medium; free cholesterol, however, does not change this effect. Various progesterones also protect red cell from osmotic lysis, but only if the erythrocytes are directly exposed to the compounds present in the hypotonic NaCl solutions used for measurement of their osmotic fragility. Progesterones do not remain in the membrane after the cells have been washed. The OSC are also capable of correcting the osmotic fragility curve of red cells from patients with hereditary spherocytosis. These experiments may suggest an approach to the pharmacologic treatment of hereditary spherocytosis.

scholarly journals Diminished osmotic fragility of human erythrocytes following the membrane insertion of oxygenated sterol compounds

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 317-325 ◽  
Author(s):  
RA Streuli ◽  
JR Kanofsky ◽  
RB Gunn ◽  
S Yachnin
Keyword(s):  
Cell Membrane ◽  
Hereditary Spherocytosis ◽  
Osmotic Fragility ◽  
Human Erythrocytes ◽  
Fragility Curve ◽  
Membrane Insertion ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Mean Cell Volume ◽  
Osmotic Lysis

Abstract Oxygenated sterol compounds (OSC), when incubated for 1 hr with human erythrocytes in lipoprotein-depleted medium at concentrations of 0.625- 5 X 10(-5) M, are inserted into the cell membrane and remain there despite subsequent washing of the cells. The insertion results in expansion of the surface area of the red cell ghost membrane, an increase in critical hemolytic volume, and as a consequence, in diminished osmotic fragility of the erythrocytes. This effect is seen with echinocyte-forming as well as with non-echinocyte-forming OSC. Erythrocytes treated with OSC do not differ from control cells with respect to their mean cell volume (MCV) in isotonic solution, water content, ion fluxes, and filterability through polycarbonate filters. The shift of the osmotic fragility curve toward lower NaCl concentrations is proportional to the amount of OSC inserted into the red cell membrane. 7 beta-Hydroxycholesterol, 22-ketocholesterol, and 20 alpha-hydroxycholesterol are the most potent inhibitors of osmotic lysis. The effect of OSC on osmotic fragility is diminished if the erythrocytes are incubated in a lipoprotein-containing medium; free cholesterol, however, does not change this effect. Various progesterones also protect red cell from osmotic lysis, but only if the erythrocytes are directly exposed to the compounds present in the hypotonic NaCl solutions used for measurement of their osmotic fragility. Progesterones do not remain in the membrane after the cells have been washed. The OSC are also capable of correcting the osmotic fragility curve of red cells from patients with hereditary spherocytosis. These experiments may suggest an approach to the pharmacologic treatment of hereditary spherocytosis.

The distribution of spectrin along the membranes of normal and echinocytic human erythrocytes

1978 ◽  
Vol 34 (1) ◽  
pp. 91-101
Author(s):  
E. Ziparo ◽  
A. Lemay ◽  
V.T. Marchesi
Keyword(s):  
Cell Membrane ◽  
Cell Shape ◽  
Human Erythrocytes ◽  
Atp Depletion ◽  
Red Cell ◽  
Significant Extent ◽  
Red Cell Membrane ◽  
Extrusion Mechanism ◽  
The Stability ◽  
Spectrin Network

Spectrin molecules are distributed uniformly throughout the submembranous regions of intact human erythrocytes. Spectrin does not appear to extend into the red blood cell cytoplasm to any significant extent. Thus, it does not form a recognizable internal scaffolding nor does it seem to connect distant segments of the cell membrane. Spectrin retains its submembranous location in the spiny processes of echinocytes produced by ATP depletion. Thus, these processes do not seem to form by a simple extrusion mechanism powered by contraction of the spectrin network. Spectrin seems to be important for the stability of the lipid bilayer of the red cell membrane, and it probably also plays a role in regulating red cell shape. How it performs either function is still unknown.

DIFFUSION BOUNDARY LAYER TRANSPORT IN GRACILARIA CONFERTA(RHODOPHYTA)1

1995 ◽  
Vol 31 (5) ◽  
pp. 768-773 ◽  
Author(s):  
Yael Gonen ◽  
Eitan Kimmel ◽  
Michael Friedlander
Keyword(s):  
Boundary Layer ◽  
Diffusion Boundary Layer ◽  
Diffusion Boundary ◽  
Gracilaria Conferta
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