Effects of divalent cations, temperature, osmotic pressure gradient, and vesicle curvature on phosphatidylserine vesicle fusion

1984 ◽  
Vol 77 (3) ◽  
pp. 265-275 ◽  
Author(s):  
Shinpei Ohki
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Divalent Cations ◽  
Vesicle Fusion ◽  
Osmotic Pressure Gradient

Protein osmotic pressure gradients and microvascular reflection coefficients

1997 ◽  
Vol 273 (2) ◽  
pp. H997-H1002 ◽  
Author(s):  
R. E. Drake ◽  
S. Dhother ◽  
R. A. Teague ◽  
J. C. Gabel
Keyword(s):  
Reflection Coefficient ◽  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Reflection Coefficients ◽  
Pressure Gradients ◽  
Fluid Filtration ◽  
The Mean ◽  
Osmotic Reflection Coefficient ◽  
New Equation ◽  
Osmotic Pressure Gradient

Microvascular membranes are heteroporous, so the mean osmotic reflection coefficient for a microvascular membrane (sigma d) is a function of the reflection coefficient for each pore. Investigators have derived equations for sigma d based on the assumption that the protein osmotic pressure gradient across the membrane (delta II) does not vary from pore to pore. However, for most microvascular membranes, delta II probably does vary from pore to pore. In this study, we derived a new equation for sigma d. According to our equation, pore-to-pore differences in delta II increase the effect of small pores and decrease the effect of large pores on the overall membrane osmotic reflection coefficient. Thus sigma d for a heteroporous membrane may be much higher than previously derived equations indicate. Furthermore, pore-to-pore delta II differences increase the effect of plasma protein osmotic pressure to oppose microvascular fluid filtration.

Freezing point depression of rat kidney slices during water diuresis and antidiuresis

1960 ◽  
Vol 199 (5) ◽  
pp. 915-918 ◽  
Author(s):  
George A. Bray
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Freezing Point ◽  
Rat Kidney ◽  
Freezing Point Depression ◽  
Water Diuresis ◽  
Outer Medulla ◽  
Kidney Slices ◽  
Outer Stripe ◽  
Osmotic Pressure Gradient

The freezing point depression of slices of rat kidney removed during water diuresis or antidiuresis has been investigated with a microcryoscopic method. The osmotic pressure gradient in the inner medulla first demonstrated by Wirz has been confirmed. The inner medulla was found to be hypertonic to plasma during water diuresis. Hypotonic tubules were present throughout the cortex and outer stripe of the outer medulla.

New Thermal Energy Converters Based on Polyelectrolyte Hydrogels

2014 ◽  
Vol 1037 ◽  
pp. 117-122 ◽  
Author(s):  
Ibragim Suleimenov ◽  
Andrei Falaleev ◽  
Dina Shaltykova ◽  
Sergei Panchenko ◽  
Grigoriy Mun
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Thermal Energy ◽  
Motion Equations ◽  
Mobile Ions ◽  
Local Value ◽  
Osmotic Pressure Gradient ◽  
Energy Converters

The theory of thermal energy converters based on polyelectrolyte hydrogels has been developed. The possibility of providing the circulation of a fluid in the contour by controlled variations of the local value of concentrations of the mobile ions that cause an osmotic pressure gradient was shown. On the basis of the solution of motion equations of the mobile ions the numerical estimates of parameters of proposed type of circulation contour are given.

scholarly journals Sodium Movement across Single Perfused Proximal Tubules of Rat Kidneys

1964 ◽  
Vol 47 (6) ◽  
pp. 1175-1194 ◽  
Author(s):  
Gerhard Giebisch ◽  
Ruth M. Klose ◽  
Gerhard Malnic ◽  
W. James Sullivan ◽  
Erich E. Windhager
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Water Movement ◽  
Rat Kidney ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Colloid Osmotic Pressure ◽  
Concentration Difference ◽  
The Relationship ◽  
Osmotic Pressure Gradient

Using perfusion techniques in single proximal tubule segments of rat kidney, the relationship between net sodium movement and active transport of ions, as measured by the short-circuit method, has been studied. In addition, the role of the colloid-osmotic pressure gradient in proximal transtubular fluid and sodium movement has been considered. Furthermore, the limiting concentration gradient against which sodium movement can occur and the relationship between intratubular sodium concentration and fluid transfer have been investigated. Comparison of the short-circuit current with the reabsorptive movement of sodium ions indicates that this process is largely, perhaps exclusively, active in nature. No measurable contribution of the normally existing colloid-osmotic pressure gradient to transtubular water movement was detected. On the other hand, fluid movement across the proximal tubular epithelium is dependent upon the transtubular sodium gradient and is abolished when a mean concentration difference of 50 mEq/liter is exceeded.

Peritoneal Transport Characteristics with Glycerol-Based Dialysate in Peritoneal Dialysis

2000 ◽  
Vol 20 (5) ◽  
pp. 557-565 ◽  
Author(s):  
Watske Smit ◽  
Dirk R. De Waart ◽  
Dirk G. Struijk ◽  
Raymond T. Krediet
Keyword(s):  
Molecular Weight ◽  
Peritoneal Dialysis ◽  
Pressure Gradient ◽  
Solute Transport ◽  
Osmotic Pressure ◽  
Low Molecular Weight ◽  
Osmotic Gradient ◽  
Plasma Ratio ◽  
Osmotic Agent ◽  
Osmotic Pressure Gradient

Background Glycerol is a low molecular weight solute (MW 92 D) that can be used as an osmotic agent in continuous ambulatory peritoneal dialysis (CAPD). Due to its low molecular weight, the osmotic gradient disappears rapidly. Despite the higher osmolality at the beginning of a dwell, ultrafiltration has been found to be lower for glycerol compared to glucose (MW 180 D) when equimolar concentrations are used. Previous studies have shown glycerol to be safe for long-term use, but some discrepancies have been reported in small solute transport and protein loss. Objective To assess permeability characteristics for a 1.4% glycerol dialysis solution compared to 1.36% glucose. Design Two standardized peritoneal permeability analyses (SPA), one using 1.4% glycerol and the other using 1.36% glucose, in random order, were performed within a span of 2 weeks in 10 stable CAPD patients. The length of the study dwell was 4 hours. Fluid kinetics and solute transport were calculated and signs of cell damage were compared for the two solutions. Setting Peritoneal dialysis unit in the Academic Medical Center, Amsterdam. Results Median values for the 1.4% glycerol SPA were as follows: net ultrafiltration 251 mL, which was higher than that for 1.36% glucose (12 mL, p < 0.01); transcapillary ultrafiltration rate 2.12 mL/min, which was higher than that for glucose (1.52 mL/min, p = 0.01); and effective lymphatic absorption rate 1.01 mL/min, which was not different from the glucose-based solution. Calculation of peritoneal reflection coefficients for glycerol and glucose showed lower values for glycerol compared to glucose (0.03 vs 0.04, calculated with both the convection and the diffusion models). A marked dip in dialysate-to-plasma ratio for sodium was seen in the 1.4% glycerol exchange, suggesting uncoupled water transport through water channels. Mass transfer area coefficients for urea, creatinine, and urate were similar for both solutions. Also, clearances of the macromolecules P2-microglobulin, albumin, IgG, and α2-macroglobulin were not different for the two osmotic agents. The median absorption was higher for glycerol, 71% compared to 49% for glucose ( p < 0.01), as could be expected from the lower molecular weight. The use of a 1.4% glycerol solution during a 4-hour dwell caused a small but significant median rise in plasma glycerol, from 0.22 mmol/L to 0.45 mmol/L ( p = 0.02). Dialysate cancer antigen 125 and lactate dehydrogenase (LDH) concentrations during the dwell were not different for both solutions. Conclusions These findings show that glycerol is an effective osmotic agent that can replace glucose in short dwells and show no acute mesothelial damage. The higher net ultrafiltration obtained with 1.4% glycerol can be explained by the higher initial net osmotic pressure gradient. This was seen especially in the first hour of the dwell. Thereafter, the osmotic gradient diminished as a result of absorption. The dip in dialysate-to-plasma ratio for sodium seen in the glycerol dwell can also be explained by this high initial osmotic pressure gradient, implying that the effect of glycerol as an osmotic agent is more dependent on intact water channels than is glucose.

Osmosis and Solute Size: A Molecular Dynamics Study

2011 ◽  
Author(s):  
James Cannon ◽  
Daejoong Kim ◽  
Shigeo Maruyama ◽  
Junichiro Shiomi
Keyword(s):  
Molecular Dynamics ◽  
Pressure Gradient ◽  
Molecular Dynamics Simulations ◽  
Osmotic Pressure ◽  
Essential Role ◽  
Osmotic Gradient ◽  
Wide Range ◽  
Dynamics Simulations ◽  
Osmotic Pressure Gradient

Osmosis plays an essential role in a wide range of phenomena, and therefore it is useful to understand how to manipulate the rate at which osmosis occurs. In the present study we conduct molecular dynamics simulations to consider the influence of solute size on the osmotic pressure gradient which drives the flow. Our results show how selective choice of the size of the solute can enhance, or hinder, the establishment of a strong osmotic gradient.

Degradation of supported liquid membranes under an osmotic pressure gradient

1987 ◽  
Vol 30 (1) ◽  
pp. 97-104 ◽  
Author(s):  
C. Fabiani ◽  
M. Merigiola ◽  
G. Scibona ◽  
A.M. Castagnola
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Liquid Membranes ◽  
Supported Liquid Membranes ◽  
Osmotic Pressure Gradient

scholarly journals Free water transport, small pore transport and the osmotic pressure gradient

2008 ◽  
Vol 23 (7) ◽  
pp. 2350-2355 ◽  
Author(s):  
A. Parikova ◽  
W. Smit ◽  
M. M. Zweers ◽  
D. G. Struijk ◽  
R. T. Krediet
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Water Transport ◽  
Free Water ◽  
Small Pore ◽  
Osmotic Pressure Gradient
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