Differential action of plasma and albumin on transcapillary exchange of anionic solute

1993 ◽  
Vol 264 (5) ◽  
pp. H1428-H1437 ◽  
Author(s):  
V. H. Huxley ◽  
F. E. Curry ◽  
M. R. Powers ◽  
B. Thipakorn
Keyword(s):  
Reflection Coefficient ◽  
Permeability Coefficient ◽  
Protein Composition ◽  
Solvent Drag ◽  
Solute Permeability ◽  
Charge Selectivity ◽  
Microvessel Wall ◽  
Solute Permeability Coefficient ◽  
Differential Action ◽  
Alpha Lactalbumin

We tested two hypotheses to account for the reduction in coupling of anionic solute to water flow (solvent drag) in microvessels during perfusion with plasma compared with albumin. Solvent drag is determined by both hydraulic conductivity (Lp) and solute reflection coefficient (sigma). Accordingly, decreased solvent drag during plasma perfusion must be the result of an increase in sigma (hypothesis 1) or reduction of Lp (hypothesis 2) or some combination of both mechanisms. These hypotheses were assessed by measuring Lp, sigma, and diffusive solute permeability (Psd) to the anionic protein alpha-lactalbumin in frog mesenteric exchange microvessels during plasma or albumin perfusion. The solute permeability coefficient to alpha-lactalbumin (Ps alpha-lactalbumin) was lower during exposure to plasma than bovine serum albumin (BSA) [(Ps alpha-lactalbumin)plasma/(Ps alpha-lactalbumin)BSA = 0.31 +/- 0.11 (means +/- SE, n = 9)]. Solute reflection coefficient to alpha-lactalbumin (sigma alpha-lactalbumin) was 0.69 +/- 0.02 in plasma and 0.34 +/- 0.03 in BSA (n = 7). Lp was not significantly influenced by perfusate protein composition (Lp plasma/Lp BSA = 1.02 +/- 0.11; n = 20). These data lead to the conclusion that the actions of plasma are to confer charge selectivity for anionic solute and, to a lesser extent, modify the porous pathways of the microvessel wall. Taken together, these results indicate that porous pathways contribute significantly to macromolecular flux in plasma-perfused vessels.

Modulation of microvessel wall charge by plasma glycoprotein orosomucoid

1989 ◽  
Vol 257 (5) ◽  
pp. H1354-H1359 ◽  
Author(s):  
F. E. Curry ◽  
J. C. Rutledge ◽  
J. F. Lenz
Keyword(s):  
Permeability Coefficient ◽  
Net Charge ◽  
Solute Permeability ◽  
Stokes Radius ◽  
Plasma Glycoprotein ◽  
Albumin Clearance ◽  
Wall Charge ◽  
Microvessel Wall ◽  
Solute Permeability Coefficient ◽  
Alpha Lactalbumin

Haraldsson and Rippe suggested that the circulating glycoprotein orosomucoid (alpha 1-acid glycoprotein) contributes to the net charge on microvessel walls (Acta Physiol. Scand. 129: 127-135, 1987). We tested their hypothesis in individually perfused microvessels of frog mesentery by measuring solute permeability coefficients of two globular proteins (alpha-lactalbumin and ribonuclease) having approximately the same size (Stokes radius, 2 nm) but different charge (-11 and +3, respectively). In vessels perfused with orosomucoid (0.1 and 1 mg/ml) in a Ringer-albumin perfusate, the solute permeability coefficient of alpha-lactalbumin decreased to one-half [0.47 +/- 0.25 (SD)] the value in the absence of orosomucoid, and the solute permeability coefficient of ribonuclease was close to six times as large as alpha-lactalbumin permeability. Both results may be accounted for if orosomucoid increases the net negative charge on microvessel walls in frog mesentery from 11.2 to 28 meq/l. A similar change in microvessel charge would be more than sufficient to account for the decrease in albumin clearance in the presence of orosomucoid reported by Haraldsson and Rippe in rat muscle microvessels.

Differential actions of albumin and plasma on capillary solute permeability

1991 ◽  
Vol 260 (5) ◽  
pp. H1645-H1654 ◽  
Author(s):  
V. H. Huxley ◽  
F. E. Curry
Keyword(s):  
Blue Dye ◽  
Albumin Concentration ◽  
Solute Permeability ◽  
Charge Selectivity ◽  
Plasma Factor ◽  
Albumin Content ◽  
Initial Control ◽  
Tetramethylrhodamine Isothiocyanate ◽  
Microvessel Wall ◽  
Alpha Lactalbumin

We tested the hypothesis that albumin regulates the solute permeability coefficients (Ps) of individually perfused exchange microvessels of the frog mesentery by mechanisms similar to those described for hydraulic conductivity. Using unbound Evans blue dye (T-1824, mol wt 960, 1.3 nm radius) as a test solute, we demonstrated a hysteresis of PT-1824s on luminal albumin content as perfusate albumin concentration was first reduced in three steps from 1 mg/ml to zero and then returned to 1 mg/ml. PT-1824 s did not return to initial control values. The same result was found with tetramethylrhodamine isothiocyanate-alpha-lactalbumin (mol wt 14,176; 2.0 nm radius) even when the perfusate albumin concentration was increased by 10-fold to 10 mg/ml. In contrast, frog plasma at the same total protein concentration restored P alpha-lactalbumin s to values below those measured with control albumin perfusates before Ringer perfusion. Our results conform to the hypothesis that a plasma factor (possibly orosomucoid) that modifies the charge selectivity of the microvessel wall is removed from the microvessel membrane during protein-free Ringer perfusion and is not restored by reperfusion with albumin alone.

Graded modulation of frog microvessel permeability to albumin using ionophore A23187

1990 ◽  
Vol 258 (2) ◽  
pp. H587-H598 ◽  
Author(s):  
F. E. Curry ◽  
W. L. Joyner ◽  
J. C. Rutledge
Keyword(s):  
Endothelial Cells ◽  
Permeability Coefficient ◽  
Ionophore A23187 ◽  
Solvent Drag ◽  
Solute Permeability ◽  
Fibrous Matrix ◽  
Microvessel Permeability ◽  
Quantitative Fluorescence ◽  
Peak Value ◽  
Sustained Increase

We investigated the exchange of water and macromolecules across venular microvessels after permeability was increased. Quantitative fluorescence microscopy was used to measure albumin permeability coefficients in individually perfused microvessels of decerebrate frogs. Control permeability coefficient was 2.3 +/- 0.25 X 10(-7) cm/s. Solvent drag increased the apparent solute permeability coefficient (Ps) by 0.57 +/- 0.05 X 10(-7) cm/s for each cmH2O increase in microvessel pressure. The divalent cation ionophore A23187 (0.1–5 microM) produced a transient increase in Ps to a peak value (within 1–3 min), followed (after 4–8 min) by a sustained increase in permeability (16–34% of peak values). Peak values of Ps were 13 and 80 times control for 0.1 and 5 microM A23187, respectively. Both diffusion and solvent drag contributed to the sustained increase in Ps. The equivalent pore radius of the structures determining diffusion and solvent drag was less than or equal to 25 nm during the sustained increase in permeability, smaller than observed gaps between adjacent endothelial cells. The basement membrane and a fibrous matrix secreted by endothelial cells into the gaps may offer resistance to exchange in the high permeability state.

scholarly journals A Physical Interpretation of the Phenomenological Coefficients of Membrane Permeability

1961 ◽  
Vol 45 (1) ◽  
pp. 143-179 ◽  
Author(s):  
O. Kedem ◽  
A. Katchalsky
Keyword(s):  
Reflection Coefficient ◽  
Physical Interpretation ◽  
Electrical Current ◽  
Distribution Coefficients ◽  
Ion Concentration ◽  
Solute Permeability ◽  
Reference Curves ◽  
Phenomenological Coefficients ◽  
Charged Membranes ◽  
Solute Permeability Coefficient

A "translation" of the phenomenological permeability coefficients into friction and distribution coefficients amenable to physical interpretation is presented. Expressions are obtained for the solute permeability coefficient ω and the reflection coefficient σ for both non-electrolytic and electrolytic permeants. An analysis of the coefficients is given for loose membranes as well as for dense natural membranes where transport may go through capillaries or by solution in the lipoid parts of the membrane. Water diffusion and filtration and the relation between these and capillary pore radius of the membrane are discussed. For the permeation of ions through the charged membranes equations are developed for the case of zero electrical current in the membrane. The correlation of σ with ω and Lp for electrolytes resembles that for non-electrolytes. In this case ω and σ depend markedly on ion concentration and on the charge density of the membrane. The reflection coefficient may assume negative values indicating anomalous osmosis. An analysis of the phenomena of anomalous osmosis was carried out for the model of Teorell and Meyer and Sievers and the results agree with the experimental data of Loeb and of Grim and Sollner. A set of equations and reference curves are presented for the evaluation of ω and σ in the transport of polyvalent ions through charged membranes.

Quantitative fluorescence microscopy on single capillaries: alpha-lactalbumin transport

1987 ◽  
Vol 252 (1) ◽  
pp. H188-H197 ◽  
Author(s):  
V. H. Huxley ◽  
F. E. Curry ◽  
R. H. Adamson
Keyword(s):  
Capillary Pressure ◽  
Capillary Wall ◽  
Solute Flux ◽  
Fluorescent Light ◽  
Solvent Drag ◽  
Solute Permeability ◽  
Water Pathway ◽  
Alpha Lactalbumin

We have extended the use of a microscope densitometric technique [Am. J. Physiol. 245 (Heart Circ. Physiol. 14): H495-H505, 1983] to measure the solute permeability coefficients (Pa) of fluorescently labeled solutes in single perfused capillaries of frog mesentery. The method enables the transcapillary flux of solutes larger than 10,000 mol wt to be measured under conditions where the forces that determine both solute and water flows across the capillary wall are known. The Pa for alpha-lactalbumin (mol wt 14,176, Stokes radius 2.02 nm) increased from a mean value of 2.1 X 10(-6) cm/s when capillary pressure was 3.0 cmH2O (no net filtration) to greater than 4.0 X 10(-6) cm/s when capillary pressure was 15 cmH2O. Taking a value of 0.35 for the solvent drag reflection coefficient for alpha-lactalbumin, we conclude that the increased solute flux represents solvent drag through a water pathway with a hydraulic conductivity of 3.6 X 10(-7) cm X s-1 X cmH2O-1. Our data conforms to the hypothesis that alpha-lactalbumin is transported across the capillary wall by restricted diffusion and solvent drag in a pathway that carries 90% of the transcapillary water flow (the principle water pathway). In vitro and in vivo calibration experiments have been carried out to test the assumption that the measured fluorescent light intensity is proportional to the number of fluorescent molecules in the measuring window of the photometer.

scholarly journals Dynamics of osmosis in a porous medium

2014 ◽  
Vol 1 (3) ◽  
pp. 140352 ◽  
Author(s):  
Silvana S. S. Cardoso ◽  
Julyan H. E. Cartwright
Keyword(s):  
Porous Medium ◽  
Permeability Coefficient ◽  
Driving Forces ◽  
Pore Space ◽  
Solute Permeability ◽  
Empirical Relations ◽  
Solvent Molecules ◽  
Semi Empirical ◽  
Osmotic Effects ◽  
Solute Permeability Coefficient

We derive from kinetic theory, fluid mechanics and thermodynamics the minimal continuum-level equations governing the flow of a binary, non-electrolytic mixture in an isotropic porous medium with osmotic effects. For dilute mixtures, these equations are linear and in this limit provide a theoretical basis for the widely used semi-empirical relations of Kedem & Katchalsky (Kedem & Katchalsky 1958 Biochim. Biophys. Acta 27 , 229–246 ( doi:10.1016/0006-3002(58)90330-5 ), which have hitherto been validated experimentally but not theoretically. The above linearity between the fluxes and the driving forces breaks down for concentrated or non-ideal mixtures, for which our equations go beyond the Kedem–Katchalsky formulation. We show that the heretofore empirical solute permeability coefficient reflects the momentum transfer between the solute molecules that are rejected at a pore entrance and the solvent molecules entering the pore space; it can be related to the inefficiency of a Maxwellian demi-demon.

scholarly journals Implementation of Spiegler–Kedem and Steric Hindrance Pore Models for Analyzing Nanofiltration Membrane Performance for Smart Water Production

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 78 ◽  
Author(s):  
Remya Nair ◽  
Evgenia Protasova ◽  
Skule Strand ◽  
Torleiv Bilstad
Keyword(s):  
Mass Transfer ◽  
Reflection Coefficient ◽  
Oil Recovery ◽  
Water Permeability ◽  
Structural Parameters ◽  
Pure Water ◽  
Model Parameters ◽  
Water Production ◽  
Solute Permeability ◽  
Smart Water

A predictive model correlating the parameters in the mass transfer-based model Spiegler–Kedem to the pure water permeability is presented in this research, which helps to select porous polyamide membranes for enhanced oil recovery (EOR) applications. Using the experimentally obtained values of flux and rejection, the reflection coefficient σ and solute permeability Ps have been estimated as the mass transfer-based model parameters for individual ions in seawater. The reflection coefficient and solute permeability determined were correlated with the pure water permeability of a membrane, which is related to the structural parameters of a membrane. The novelty of this research is the development of a model that consolidates the various complex mechanisms in the mass transfer of ions through the membrane to an empirical correlation for a given feed concentration and membrane type. These correlations were later used to predict ion rejections of any polyamide membrane with a known pure water permeability and flux with seawater as a feed that aids in the selection of suitable nanofiltration (NF) for smart water production.

scholarly journals Composition of major proteins in cow milk differing in mean protein concentration during the first 155 days of lactation and the influence of season as well as short-term restricted feeding in early and mid-lactation

2014 ◽  
Vol 59 (No. 3) ◽  
pp. 97-106 ◽  
Author(s):  
K. Gellrich ◽  
H.H.D. Meyer ◽  
S. Wiedemann
Keyword(s):  
Milk Protein ◽  
Acute Stress ◽  
Relative Concentration ◽  
Protein Composition ◽  
Experimental Period ◽  
Stress Factors ◽  
Cow Milk ◽  
Beta Casein ◽  
Beta Lactoglobulin ◽  
Alpha Lactalbumin

A variety of proteins contributes greatly to the unique nutritional and functional quality of dairy cow milk. Particularly, milk casein content and composition have substantial influence on the processing capabilities. In the present study, milk of 23 multiparous Holstein-Friesian cows, grouped as high- (3.49 ± 0.05%; n = 11) and low-protein (3.03 ± 0.05%; n = 12) cows, was sampled approximately weekly during the first 155 days of lactation to determine the course of relative milk protein composition (α-lactalbumin; β-lactoglobulin; α-, β-, and κ-casein). Furthermore, feed restrictions by 30% of dry matter intake in early and mid-lactation as well as experimental tissue biopsies were conducted to observe their effect on milk protein composition. Milk protein composition was relatively stable and displayed similar concentration patterns throughout the experimental period between both groups. Mean relative concentrations of α-, β-, κ-casein, α-lactalbumin, and β-lactoglobulin were 34.2, 31.4, 16.0, 2.1, and 9.7% of total protein, respectively. Feed restrictions did not alter milk protein composition, whereas the season influenced α- and β-casein as well as α-lactalbumin. Further, effects were observed in both groups at times of unfamiliar stressful situations caused by taking liver or muscle biopsies. As a result, the relative concentration of β-casein increased. Therefore, acute stress factors may lead to a deviation in milk protein composition and should be avoided.  

scholarly journals Effects of solvent and solute drag on transmembrane diffusion.

1982 ◽  
Vol 79 (3) ◽  
pp. 507-528 ◽  
Author(s):  
J T Van Bruggen ◽  
B Chalmers ◽  
M Muller
Keyword(s):  
Solute Drag ◽  
Tracer Diffusion ◽  
The Other ◽  
Solute Flux ◽  
Solvent Drag ◽  
Solution Flow ◽  
Solute Permeability ◽  
Drag Forces ◽  
Transmembrane Diffusion

The present study compares and quantitates both solvent drag and solute drag forces in a system with both heteropore and homopore membranes. It is shown that tracer solute permeability can be increased if solution flow or driver solute flux is in the direction of tracer diffusion. Either force can decrease tracer permeability if the force can decrease tracer permeability if the force is opposite to the direction of tracer diffusion. The two forces can be additive or one force may reduce the effect of the other force. In the particular system quantitated, solute drag is shown to be some 300 times more effective than solvent drag on a mole-to-mole basis. The use of a number of solute pairs on other homopore and heteropore membranes confirms the finding that the two drag forces can be analyzed or manipulated in a variety of systems.

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