Interaction of transcapillary Starling forces in the isolated dog forelimb

Three of the four Starling forces were measured in the intact dog forelimb after anesthetization and all four of the Starling forces were measured in the same forelimb which was surgically isolated yet innervated. In the isolated forelimb, isogravimetric capillary pressure (Pci) averaged 15.6 mmHg; colloid osmotic pressure of the plasma proteins (IIp) averaged 19.9 mmHg; mean interstitial fluid pressure (Pif) was +0.4 mmHg, and the average value of interstitial colloid osmotic pressure (IIif) was 4.9 mmHg. Thus the net imbalance in the Starling forces, i.e., (Pci - Pif) - (IIp - IIif), averaged 0.3 mmHg. Furthermore, the value of IIif was consistently decreased after isolation (average decrease of 1.2 mmHg) while Pif was always increased following isolation (average increase of 4.3 mmHg). In addition, it was found that if the forelimb was denervated during isolation, then Pif was increased by an average of 2 mmHg above Pif in the innervated, isolated forelimb. In summary, these studies show that the differences between the intact and isolated forelimb are that Pci averages 10-11 mmHg in the intact forelimb and 15-16 mmHg in the isolated innervated forelimb while interstitial fluid pressure is negative in the intact limb and positive in the isolated limb.

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Transcapillary Starling forces using membrane osmometry

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1980.238.6.h886 ◽

1980 ◽

Vol 238 (6) ◽

pp. H886-H888

Author(s):

J. L. Christian ◽

R. A. Brace

Keyword(s):

Osmotic Pressure ◽

Interstitial Fluid ◽

Subcutaneous Tissue ◽

Fluid Pressure ◽

Colloid Osmotic Pressure ◽

Interstitial Fluid Pressure ◽

Tissue Samples ◽

Small Pore ◽

The Difference ◽

Good Agreement

Membrane osmometry was used to estimate the four transcapillary Starling pressures in subcutaneous tissue of rats, guinea pigs, and dogs. Isolated subcutaneous tissue samples were either placed on a large-pore or small-pore osmometer that measured the interstitial fluid pressure (Pif) and the difference between the interstitial fluid pressure and the interstitial protein osmotic pressure (Pif-pi if), respectively. The colloid osmotic pressure of the interstitial fluid (pi if) was obtained from the difference in these two pressures. A plasma sample placed on the small-pore osmometer yielded the colloid osmotic pressure of the plasma proteins (pi c). Finally the capillary pressure (Pc) was calculated from the three other Starling forces. In the rat, guinea pig, and dog, respectively, the estimated Starling forces were as follows: Pif -2.2, -2.1, and -4.8 mmHg; pi if, 7.3, 4.8, and 4.4 mmHg; pi c, 21.3, 19.5, and 19.2 mmHg; and Pc, 11.8, 12.6, and 10.0 mmHg. A comparison with data obtained in other studies using different methods shows good agreement and strongly supports membrane osmometry as a method for measuring the Starling pressures in subcutaneous tissue.

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Lowering of interstitial fluid pressure in rat submandibular gland: a novel mechanism in saliva secretion

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00887.2005 ◽

2006 ◽

Vol 290 (4) ◽

pp. H1460-H1468 ◽

Cited By ~ 4

Author(s):

Ellen Berggreen ◽

Helge Wiig

Keyword(s):

Osmotic Pressure ◽

Submandibular Gland ◽

Interstitial Fluid ◽

Fluid Transport ◽

Fluid Pressure ◽

Myoepithelial Cells ◽

Colloid Osmotic Pressure ◽

Interstitial Fluid Pressure ◽

High Rate ◽

Fluid Filtration

The submandibular gland transports fluid at a high rate through the interstitial space during salivation, but the exact level of all forces governing transcapillary fluid transport has not been established. In this study, our aim was to measure the relation between interstitial fluid volume (Vi) and interstitial fluid pressure (Pif) in salivary glands during active secretion and after systemically induced passive changes in gland hydration. We tested whether interstitial fluid could be isolated by tissue centrifugation to enable measurement of interstitial fluid colloid osmotic pressure. During control conditions, Vi averaged 0.23 ml/g wet wt (SD 0.014), with a corresponding mean Pif measured with micropipettes of 3.0 mmHg (SD 1.3). After induction of secretion by pilocarpine, Pif dropped by 3.8 mmHg (SD 1.5) whereas Vi was unchanged. During dehydration and overhydration of up to 20% increase of Vi above control, a linear relation was found between volume and pressure, resulting in a compliance (ΔVi/ΔPif) of 0.012 ml·g wet wt−1·mmHg−1. Interstitial fluid was isolated, and interstitial fluid colloid osmotic pressure averaged 10.4 mmHg (SD 1.2), which is 64% of the corresponding level in plasma. We conclude that Pif drops during secretion and, thereby, increases the net transcapillary pressure gradient, a condition that favors fluid filtration and increases the amount of fluid available for secretion. The reduction in Pif is most likely induced by contraction of myoepithelial cells and suggests an active and new role for these cells in salivary secretion. The relatively low interstitial compliance of the organ will enhance the effect of the myoepithelial cells on Pif during reduced Vi.

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Tissue pressure and plasma oncotic pressure during exercise

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.1.102 ◽

1984 ◽

Vol 56 (1) ◽

pp. 102-108 ◽

Cited By ~ 13

Author(s):

V. Mohsenin ◽

R. R. Gonzalez

Keyword(s):

Osmotic Pressure ◽

Plasma Volume ◽

Interstitial Fluid ◽

Vastus Lateralis ◽

Fluid Pressure ◽

Colloid Osmotic Pressure ◽

Interstitial Fluid Pressure ◽

Plasma Sodium ◽

Vastus Lateralis Muscle ◽

Base Line

Six healthy male subjects exercised on a cycle ergometer for 3 min for assessment of forces involved in transvascular fluid shift during intense exercise. The work load was at 105% of peak O2 uptake of the subjects. This caused a 17.2 +/- 1.2% reduction in plasma volume. The plasma volume loss was associated with an increase in plasma sodium, from 142.6 +/- 0.5 to 148.1 +/- 1.0 meq X 1(-1) (P less than 0.005); chloride, from 101.8 +/- 0.6 to 104.6 +/- 0.9 meq X 1(-1) (P less than 0.005); lactate, from 1.4 +/- 0.2 to 14.0 +/- 1.5 meq X 1(-1) (P less than 0.005); and osmolality, from 283 +/- 2 to 299 +/- 3 mosmol X kg-1 H2O (P less than 0.005) within 2 min after cessation of exercise. Plasma protein increased from 7.0 +/- 0.2 to 8.1 +/- 0.3 g X dl-1 (P less than 0.005), and plasma colloid osmotic pressure from 25.1 +/- 0.6 to 30.6 +/- 1.4 mmHg (P less than 0.005) after exercise. Interstitial fluid pressure in the exercising vastus lateralis muscle increased from a base-line value (SE) of -1.0 +/- 0.9 to + 1.5 +/- 1.1 cmH2O, 14 min after the end of exercise (P less than 0.05). Interstitial fluid pressure of the triceps brachii (inactive) did not change significantly after exercise. Our data suggest that increased transvascular colloid osmotic pressure and elevation of interstitial fluid pressure become increasingly important in preventing loss of plasma volume during maximal exercise.

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Transcapillary fluid balance in immature rats. Interstitial fluid pressure, serum and interstitial protein concentration, and colloid osmotic pressure

Microvascular Research ◽

10.1016/0026-2862(77)90139-x ◽

1977 ◽

Vol 14 (1) ◽

pp. 37-43 ◽

Cited By ~ 6

Author(s):

Rolf K. Reed ◽

Knut Aukland

Keyword(s):

Osmotic Pressure ◽

Fluid Balance ◽

Protein Concentration ◽

Interstitial Fluid ◽

Fluid Pressure ◽

Colloid Osmotic Pressure ◽

Interstitial Fluid Pressure ◽

Immature Rats

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Physiological effects of pH changes on colloid osmotic pressures

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1985.248.6.h890 ◽

1985 ◽

Vol 248 (6) ◽

pp. H890-H893 ◽

Cited By ~ 1

Author(s):

B. R. Will ◽

R. A. Brace

Keyword(s):

Osmotic Pressure ◽

Interstitial Fluid ◽

Ph Dependence ◽

Fluid Pressure ◽

Human Albumin ◽

Interstitial Fluid Pressure ◽

Fluid Distribution ◽

Ground Substance ◽

Physiological Range ◽

Umbilical Cords

Our purpose was to explore the effects of variations in pH, particularly in the physiological range, on the colloid osmotic pressure (COP) of the body's fluids. Theoretically, changing pH would alter the electrical charge density on plasma proteins and the interstitial ground substance, thereby altering plasma and interstitial protein osmotic pressure as well as interstitial fluid pressure. We found that the COP of human plasma, human albumin, bovine albumin, and Wharton's jelly from human umbilical cords increased linearly as pH increased over the range of 6.0–8.0. COP of plasma and the albumins all displayed essentially the same sensitivity to pH. At equal concentrations, hyaluronate in umbilical cords was approximately 16 times more sensitive to pH than was plasma. Dextran 70 displayed no COP dependency on pH. For plasma, the albumins, and hyaluronate the pH dependence of COP on pH also decreased linearly with concentration (C in g/dl). For plasma and the albumins over the physiological range of pH, COP = COPpH 7.4 [1.00 + 0.01C (pH -7.40)] at 37 degrees C. The data suggest that, relative to the normal net transcapillary pressure gradient, physiological variations in pH affect plasma COP as well as interstitial fluid pressure and thus may play a significant role in regulating the body's fluid distribution.

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Isolation of pulmonary interstitial fluid in rabbits by a modified wick technique

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.5.l1057 ◽

2001 ◽

Vol 280 (5) ◽

pp. L1057-L1065 ◽

Cited By ~ 6

Author(s):

Daniela Negrini ◽

Alberto Passi ◽

Katia Bertin ◽

Federica Bosi ◽

Helge Wiig

Keyword(s):

Osmotic Pressure ◽

Plasma Proteins ◽

Regional Differences ◽

Protein Concentration ◽

Interstitial Fluid ◽

Lung Parenchyma ◽

Colloid Osmotic Pressure ◽

Rabbit Lung ◽

Pressure Plasma ◽

Wick Technique

Interstitial fluid protein concentration (Cprotein) values in perivascular and peribronchial lung tissues were never simultaneously measured in mammals; in this study, perivascular and peribronchial interstitial fluids were collected from rabbits under control conditions and rabbits with hydraulic edema or lesional edema. Postmortem dry wicks were implanted in the perivascular and peribronchial tissues; after 20 min, the wicks were withdrawn and the interstitial fluid was collected to measure Cprotein and colloid osmotic pressure. Plasma, perivascular, and peribronchial Cproteinvalues averaged 6.4 ± 0.7 (SD), 3.7 ± 0.5, and 2.4 ± 0.7 g/dl, respectively, in control rabbits; 4.8 ± 0.7, 2.5 ± 0.6, and 2.4 ± 0.4 g/dl, respectively, in rabbits with hydraulic edema; and 5.1 ± 0.3, 4.3 ± 0.4 and 3.3 ± 0.6 g/dl, respectively, in rabbits with lesional edema. Contamination of plasma proteins from microvascular lesions during wick insertion was 14% of plasma Cprotein. In control animals, pulmonary interstitial Cprotein was lower than previous estimates from pre- and postnodal pulmonary lymph; furthermore, although the interstitium constitutes a continuum within the lung parenchyma, regional differences in tissue content seem to exist in the rabbit lung.

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Control of interstitial fluid pressure: Role of [beta ]-integrins

Seminars in Nephrology ◽

10.1053/snep.2001.21646 ◽

2001 ◽

Vol 21 (3) ◽

pp. 222-230 ◽

Cited By ~ 42

Author(s):

Rolf K. Reed ◽

Ansgar Berg ◽

Eli-Anne B. Gjerde ◽

Kristofer Rubin

Keyword(s):

Interstitial Fluid ◽

Fluid Pressure ◽

Interstitial Fluid Pressure

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Dynamics of Interstitial Fluid Pressure in Extracellular Matrix Hydrogels in Microfluidic Devices

Journal of Biomechanical Engineering ◽

10.1115/1.4031020 ◽

2015 ◽

Vol 137 (9) ◽

Cited By ~ 5

Author(s):

Joe Tien ◽

Le Li ◽

Ozgur Ozsun ◽

Kamil L. Ekinci

Keyword(s):

Extracellular Matrix ◽

Pressure Distribution ◽

Interstitial Fluid ◽

Scaling Laws ◽

Fluid Pressure ◽

Interstitial Fluid Pressure ◽

External Loading ◽

Interstitial Pressure ◽

Time Resolved ◽

Long Time

In order to understand how interstitial fluid pressure and flow affect cell behavior, many studies use microfluidic approaches to apply externally controlled pressures to the boundary of a cell-containing gel. It is generally assumed that the resulting interstitial pressure distribution quickly reaches a steady-state, but this assumption has not been rigorously tested. Here, we demonstrate experimentally and computationally that the interstitial fluid pressure within an extracellular matrix gel in a microfluidic device can, in some cases, react with a long time delay to external loading. Remarkably, the source of this delay is the slight (∼100 nm in the cases examined here) distension of the walls of the device under pressure. Finite-element models show that the dynamics of interstitial pressure can be described as an instantaneous jump, followed by axial and transverse diffusion, until the steady pressure distribution is reached. The dynamics follow scaling laws that enable estimation of a gel's poroelastic constants from time-resolved measurements of interstitial fluid pressure.

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