scholarly journals Determination of Equivalent Pore Radius for Human Red Cells by Osmotic Pressure Measurement

1960 ◽  
Vol 44 (1) ◽  
pp. 1-18 ◽  
Author(s):  
David A. Goldstein ◽  
A. K. Solomon
Keyword(s):  
Experimental Data ◽  
Pore Radius ◽  
Initial Rate ◽  
Equilibrium Concentration ◽  
External Solution ◽  
Red Cells ◽  
Cell Swelling ◽  
Zero Time ◽  
Human Red Cells

A new method has been developed to measure the equivalent pore radius in cellular membranes, and has been applied to human red cells. When red cells are suddenly introduced into a non-isosmolar concentration of non-lipid-soluble non-electrolyte molecules, water will enter or leave the cell. The rate of cell swelling or shrinking is determined and extrapolated to zero time to give the initial rate of volume change. By suitable adjustment of the concentration of the external solution the initial rate may be brought to zero. The transient equilibrium concentration, determined by interpolation from experimental data, gives a measure of Staverman's reflection coefficient, σ. The zero time method has enabled us to determine σ for nine permeant molecules. σ is directly related to the equivalent pore radius; the experimental data lead to a value of 4.2 Å for the equivalent pore radius in man, in good agreement with the previous figure of 3.5 Å given by Paganelli and Solomon. The zero time method offers a number of advantages over previous methods for determination of this parameter. It requires no measurement of the rate of water entrance into the cell, and is essentially independent of the kinetics of cell swelling. It may be applied to a variety of living cells so that many additional membranes may now be characterized in terms of their equivalent pore radius.

scholarly journals Hemoglobin Charge Dependence on Hemoglobin Concentration in Vitro

1971 ◽  
Vol 57 (3) ◽  
pp. 283-289 ◽  
Author(s):  
C. M. Gary-Bobo ◽  
A. K. Solomon
Keyword(s):  
External Solution ◽  
Hemoglobin Concentration ◽  
Bulk Water ◽  
Red Cells ◽  
A Value ◽  
Charge Dependence ◽  
Hemoglobin Molecule ◽  
Sigmoid Curve ◽  
Human Red Cells

Studies have been made of the dependence of the charge of the hemoglobin molecule on hemoglobin concentration in the concentration range between 3 and 11 mmolal. The charge has been determined by measuring the distribution of 42K between a hemoglobin solution in a cellophane bag and an external solution. The pH was 6.6, the K concentration was 10 mM, and the temperature was 4°C. The charge decreased along a sigmoid curve from a value of +3 in the most dilute solutions to a value of +0.5 in the most concentrated solutions. The results were in excellent agreement with earlier studies of Gary-Bobo and Solomon in which Cl distribution was measured between human red cells and external solutions and thus give added support to the conclusion that the apparent anomalous osmotic behavior of human red cells may be attributed to concentration-dependent changes in the hemoglobin net charge. The present findings also support the view that the water in the red cell is solvent water for K and Cl and differs in no quantitatively important respect from bulk water in free solution.

scholarly journals Anion transport in dog, cat, and human red cells. Effects of varying cell volume and Donnan ratio.

1979 ◽  
Vol 74 (3) ◽  
pp. 319-334 ◽  
Author(s):  
V Castranova ◽  
M J Weise ◽  
J F Hoffman
Keyword(s):  
Membrane Potential ◽  
Cell Volume ◽  
Rate Constant ◽  
Rate Constants ◽  
Anion Transport ◽  
Atp Depletion ◽  
Red Cells ◽  
Cell Swelling ◽  
Equilibrium Ratio ◽  
Human Red Cells

Membrane potential and the rate constants for anion self-exchange in dog, cat, and human red blood cells have been shown to vary with cell volume. For dog and cat red cells, the outward rate constants for SO4 and Cl increase while the inward rate constant for SO4 decreases as cells swell or shrink. These changes coincide with the membrane potential becoming more negative as a result of changes in cell volume. Human red cells exhibit a similar change in the rate constants for SO4 and Cl efflux in response to cell swelling, but shrunken cells exhibit a decreased rate constant for SO4 efflux and a more positive membrane potential. Hyperpolarization of shrunken dog and cat red cells is due to a volume-dependent rate constant for SO4 efflux and a more positive membrane potential. Hyperpolarization of shrunken dog and cat red cells is due to a volume-dependent increase in PNa. If this increase in PNa is prevented by ATP depletion or if the outward Na gradient is removed, the response to shrinking is identical to human red cells. These results suggest that the volume dependence of anion permeability may be secondary to changes in the anion equilibrium ratio which in red cells is reflected by the membrane potential. When the membrane potential and cell volume of human red cells were varied independently by a method involving pretreatment with nystatin, it was found that the rate of anion transport (for SO4 and Cl) does not vary with cell volume but rather with membrane potential (anion equilibrium ratio); that is, the rate constant for anion efflux is decreased and that for influx is increased as the membrane potential becomes more positive (internal anion concentration increases) while the opposite is true with membrane hyperpolarization (a fall in internal anion concentration).

scholarly journals The Quantitative Interrelationships between Ion Fluxes, Cell Swelling, and Radiation Dose in Ultraviolet Hemolysis

1965 ◽  
Vol 48 (4) ◽  
pp. 719-734 ◽  
Author(s):  
John S. Cook
Keyword(s):  
Radiation Dose ◽  
Ultraviolet Radiation ◽  
Flux Ratio ◽  
Red Cells ◽  
The Other ◽  
Cell Swelling ◽  
Ratio Criterion ◽  
Na Efflux ◽  
Ion Movements ◽  
Human Red Cells

Following treatment with ultraviolet radiation, human red cells leak cations at accelerated rates which depend on the radiation dose. With one exception (initial Na efflux), these accelerated cation fluxes fit the Ussing flux-ratio criterion for passive diffusion. Na efflux is transiently high, but with time falls to the value expected on the basis of the other cation fluxes. An equation based on the hypothesis of colloid osmotic hemolysis satisfactorily predicts the rate of cell swelling as a result of these ion movements.

Functional properties of hemoglobin in human red cells: II. Determination of the Bohr effect

1988 ◽  
Vol 73 (3) ◽  
pp. 363-378 ◽  
Author(s):  
Jean Kister ◽  
Michael C. Marden ◽  
Brigitte Bohn ◽  
Claude Poyart
Keyword(s):  
Functional Properties ◽  
Red Cells ◽  
Bohr Effect ◽  
Human Red Cells

In Vitro Assay of Platelet Adhesiveness with Washed and Tanned Human Red Cells

1968 ◽  
Vol 20 (03/04) ◽  
pp. 384-396 ◽  
Author(s):  
G Zbinden ◽  
S Tomlin
Keyword(s):  
Platelet Adhesion ◽  
Sodium Citrate ◽  
Blood Platelets ◽  
In Vitro Assay ◽  
Red Cells ◽  
Platelet Adhesiveness ◽  
Vitro Assay ◽  
In Vitro System ◽  
Human Red Cells

SummaryAn in vitro system is described in which adhesion of blood platelets to washed and tannic acid-treated red cells was assayed quantitatively by microscopic observation. ADP, epinephrine and TAME produced a reversible increase in platelet adhesiveness which was antagonized by AMP. With Evans blue, polyanetholsulfonate, phthalanilide NSC 38280, thrombin and heparin at concentrations above 1-4 u/ml the increase was irreversible. The ADP-induced increase in adhesiveness was inhibited by sodium citrate, EDTA, AMP, ATP and N-ethylmaleimide. EDTA, AMP and the SH-blocker N-ethylmaleimide also reduced spontaneous platelet adhesion to red cells. No significant effects were observed with adenosine, phenprocoumon, 5-HT, phthalanilide NSC 57155, various estrogens, progestogens and fatty acids, acetylsalicylic acid and similarly acting agents, hydroxylamine, glucose and KCN. The method may be useful for the screening of thrombogenic and antithrombotic properties of drugs.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

Numerical evaluation of hydrodynamic characteristics of planing hulls by using a hybrid method

2021 ◽  
pp. 147509022199024
Author(s):  
Emre Kahramanoglu ◽  
Silvia Pennino ◽  
Huseyin Yilmaz
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Calm Water ◽  
Preliminary Design Stage ◽  
Reduction Function ◽  
Hull Forms ◽  
Good Agreement

The hydrodynamic characteristics of the planing hulls in particular at the planing regime are completely different from the conventional hull forms and the determination of these characteristics is more complicated. In the present study, calm water hydrodynamic characteristics of planing hulls are investigated using a hybrid method. The hybrid method combines the dynamic trim and sinkage from the Zarnick approach with the Savitsky method in order to calculate the total resistance of the planing hull. Since the obtained dynamic trim and sinkage values by using the original Zarnick approach are not in good agreement with experimental data, an improvement is applied to the hybrid method using a reduction function proposed by Garme. The numerical results obtained by the hybrid and improved hybrid method are compared with each other and available experimental data. The results indicate that the improved hybrid method gives better results compared to the hybrid method, especially for the dynamic trim and resistance. Although the results have some discrepancies with experimental data in terms of resistance, trim and sinkage, the improved hybrid method becomes appealing particularly for the preliminary design stage of the planing hulls.

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