Permeability characteristics of colonic capillaries

1980 ◽  
Vol 239 (4) ◽  
pp. G300-G305 ◽  
Author(s):  
P. D. Richardson ◽  
D. N. Granger ◽  
D. Mailman ◽  
P. R. Kvietys
Keyword(s):  
Pressure Gradient ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Molecular Size ◽  
Lymph Flow ◽  
Oncotic Pressure ◽  
Plasma Protein Concentration ◽  
Permeability Characteristics ◽  
Pressure Elevation

Blood flow, lymph flow, lymph protein concentration (CL), lymph oncotic pressure, plasma protein concentration (CP), and plasma oncotic pressure were determined under steady-state conditions at venous pressures of 0, 10, 20, 30, and 40 mmHg in autoperfused segments of dog colon. Venous pressure elevation increased colonic vascular resistance, lymph flow, lymphatic protein flux, and the transcapillary oncotic pressure gradient, whereas the lymph-to-plasma protein concentration ratio (CL/CP) declined. The osmotic reflection coefficient (sigma d) was estimated using sigma d = 1-CL/CP when CL/CP is filtration independent (high lymph flows). For total protein sigma d = 0.85 +/- 0.02. Values of sigma d for plasma protein fractions with molecular radii ranging between 37 and 120 A increased as molecular radius increased. The results of this study suggest that 1) colonic capillaries selectively restrict macromolecules on the basis of molecular size, and 2) an increased lymph flow and transcapillary oncotic pressure gradient may play an important role in preventing interstitial edema subsequent to venous pressure elevation in the dog colon.

Microvascular, interstitial, and lymphatic interactions in normal heart

1985 ◽  
Vol 249 (4) ◽  
pp. H834-H842 ◽  
Author(s):  
G. A. Laine ◽  
H. J. Granger
Keyword(s):  
Plasma Protein ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Left Ventricular ◽  
Lymph Flow ◽  
Normal Heart ◽  
Oncotic Pressure ◽  
Fluid Exchange ◽  
Edema Formation ◽  
Total Plasma Protein

Control of transmicrovascular fluid exchange in the heart is of critical importance in the prevention of myocardial edema formation. To quantify the absolute values for, and the interrelationships between, the forces and flows governing fluid balance within the normal heart, the following variables were measured: arterial pressure (Pa), coronary sinus pressure (Pcs), myocardial interstitial fluid pressure (Pint), plasma protein concentration (Cp), and oncotic pressure (tau cap) along with interstitial protein concentration (CL), interstitial oncotic pressure (tau int), and left ventricular lymph flow rate (Jv). All parameters were recorded under control conditions and during graded venous pressure elevations. Control values were Pa, 125 +/- 21 mmHg; Pcs, 7.3 +/- 1.3 mmHg; Pint, 14.9 +/- 3.1 mmHg; CL/Cp, 0.82 +/- 0.12; and Jv, 7.0 +/- 2.7 ml/h. As Pcs was elevated to eight times control, Pint increased from 15 to 50 mmHg and lymph flow rose sixfold. A filtration-independent value for CL/Cp could not be obtained for total plasma protein, although a washdown CL/Cp value for beta-lipoprotein of 0.04 was obtained. Our data indicate that a large surface area of myocardial exchange vessels coupled with lymphatics of relatively low sensitivity to extravascular volume expansion produce a system that relies on a large increase in interstitial hydrostatic pressure to limit edema formation.

Effects of hypoproteinemia and increased vascular pressure on lung fluid balance in sheep

1983 ◽  
Vol 55 (5) ◽  
pp. 1514-1522 ◽  
Author(s):  
G. C. Kramer ◽  
B. A. Harms ◽  
B. I. Bodai ◽  
E. M. Renkin ◽  
R. H. Demling
Keyword(s):  
Plasma Protein ◽  
Fluid Balance ◽  
Protein Concentration ◽  
Lymph Flow ◽  
Base Line ◽  
Oncotic Pressure ◽  
Plasma Protein Concentration ◽  
Lung Fluid ◽  
Lung Fluid Balance ◽  
Normal Plasma

We compared the effects of a sustained decrease in plasma oncotic pressure on lung fluid balance with those of an increase in vascular pressure in six unanesthetized sheep. Initial plasma protein concentration of 58.0 +/- 2.2 (SE) mg/ml was quickly reduced to 34.0 +/- 1.4 mg/ml via plasmapheresis and held at this value for 24 h. Red cells were returned with lactated Ringer solution infused at a rate adjusted to maintain central venous pressure; cardiac output and pulmonary vascular pressures also remained at base line. Steady-state lymph flows increased from a base-line value of 8.8 +/- 3.2 to 20.1 +/- 5.6 ml/h, while the lymph-to-plasma protein concentration ratio ( [L/P] ) decreased from 0.65 +/- 0.03 to 0.44 +/- 0.04. Decreased lymph protein resulted in reestablishment of base-line plasma-to-lymph oncotic gradient. The increased lymph flow was not the result of increased filtration forces, since all vascular pressures and the oncotic gradient were unchanged; nor was it due entirely to increased surface area since [L/P] was decreased. The decrease in plasma oncotic pressure, delta pi P, was twice as effective at increasing lymph flow (1.66 ml X h-1 X mmHg-1, delta pi P) as an equivalent increase in microvascular pressure, delta PC, at normal plasma protein concentration (0.82 ml X h-1 X mmHg-1, delta PC). Elevation of microvascular pressure during hypoproteinemia had a greater effect on lymph flow (1.44 ml X h-1 X mmHg-1, delta PC) than at normal plasma protein concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of luminal distension on intestinal transcapillary fluid exchange

1980 ◽  
Vol 239 (6) ◽  
pp. G516-G523
Author(s):  
D. N. Granger ◽  
P. R. Kvietys ◽  
N. A. Mortillaro ◽  
A. E. Taylor
Keyword(s):  
Blood Flow ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Lymph Flow ◽  
Direct Effects ◽  
Fluid Exchange ◽  
Venous Outflow ◽  
Plasma Protein Concentration ◽  
Pressure Elevation ◽  
The Relationship

The direct effects of luminal distension pressure on intestinal transcapillary fluid exchange were studied in isolated autoperfused cat ileum preparations. Intestinal lymph flow, lymphatic pressure, lymph-to-plasma protein concentration ratio (L/P), blood flow, and perfusion pressures were allowed to reach a steady state at different luminal distension pressures (0–40 mmHg). Luminal distension was induced using a nonabsorbable silicone solution, thereby eliminating an influence of net water absorption. At a venous outflow pressure of 0 mmHg, lymph flow and lymphatic pressure increased, whereas blood flow and L/P decreased as luminal pressure was increased. The relationship between lymph flow, blood flow, and venous pressure was acquired at luminal pressures of 0 and 20 mmHg. When luminal pressure was 0, lymph flow increased and blood flow decreased progressively with venous pressure elevation; however, when luminal pressure was 20 mmHg, lymph flow and blood flow were unaffected until pressure exceeded 20 mmHg. The results of this study indicate that luminal pressure elevation enhances transcapillary fluid exchange and imposes a “waterfall” effect on the intestinal vasculature.

Interstitial fluid, plasma protein, colloid, and leukocyte uptake into initial lymphatics

1996 ◽  
Vol 81 (5) ◽  
pp. 2060-2067 ◽  
Author(s):  
Fumitaka Ikomi ◽  
James Hunt ◽  
Gayda Hanna ◽  
Geert W. Schmid-Schönbein
Keyword(s):  
Plasma Protein ◽  
Plasma Proteins ◽  
Interstitial Fluid ◽  
Venous Pressure ◽  
Particle Diameter ◽  
Lymph Flow ◽  
Material Transport ◽  
Plasma Protein Concentration ◽  
Flow Rates ◽  
Pressure Elevation

Ikomi, Fumitaka, James Hunt, Gayda Hanna, and Geert W. Schmid-Schönbein. Interstitial fluid, plasma protein, colloid, and leukocyte uptake into initial lymphatics. J. Appl. Physiol. 81(5): 2060–2067, 1996.—Lymphatics serve to remove from the interstitium a range of materials, including plasma proteins, colloid materials, and cells. Lymph flow rates can be enhanced by periodic tissue compression or venous pressure elevation, but little is known to what degree enhancement of lymph flow affects material transport. The objective was to examine the uptake of plasma proteins, a colloidal perflubron emulsion (LA-11063, mean particle diameter = 0.34 μm), and leukocytes into lymphatics. Prenodal collecting lymphatics in the lower hindlimb of rabbits were cannulated with and without foot massage and after elevation of venous pressure (40 mmHg). The average lymph flow rates were elevated ∼22-fold by the skin massage but only about threefold by venous pressure elevation. Lymph-to-plasma protein concentration ratio remained unchanged by the massage but decreased significantly after venous pressure elevation. Lymph colloid concentration and leukocyte counts were elevated on average 47 and 8.5 times, respectively, by foot massage, but both decreased after venous pressure elevation. These results suggest that skin movement by massage and elevation of the venous pressure lead to opposite lymph transport kinetics of protein, colloids, and cells. Massage is more effective to enhance material transport out of the interstitium into the initial lymphatics.

Effect of hemolysis on reflection coefficient determined by endogenous blood indicators

1987 ◽  
Vol 62 (6) ◽  
pp. 2252-2257 ◽  
Author(s):  
M. B. Maron ◽  
C. F. Pilati ◽  
K. C. Maender
Keyword(s):  
Reflection Coefficient ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Hemoglobin Concentration ◽  
Plasma Protein Concentration ◽  
Fluid Filtration ◽  
Lung Lobe ◽  
Before And After ◽  
Osmotic Reflection Coefficient

The osmotic reflection coefficient (sigma) can be estimated from the increases in hematocrit and plasma protein concentration that result from fluid filtration occurring in an isolated perfused organ. We determined what effect perfusion pump-induced hemolysis has on the value of sigma determined by this technique in both the isolated canine left lower lung lobe (LLL) and forelimb by comparing estimates of sigma obtained before and after correction for hemolysis. Hemolysis was corrected by using the slopes of the relationships between hematocrit and plasma hemoglobin concentration and between the plasma protein and hemoglobin concentrations to correct hematocrit and protein concentration to a state of zero hemolysis. Uncorrected estimates of sigma in the LLL were 1.19 +/- 0.14 (SE) at a venous pressure (Pv) of 12 Torr (n = 7) and 0.90 +/- 0.02 at a Pv of 19 Torr (n = 6). Both sets of LLL's yielded sigma values of 0.77 +/- 0.03 after hemolysis correction. In the forelimb (n = 5), uncorrected and corrected estimates of sigma of 0.99 +/- 0.03 and 0.85 +/- 0.01, respectively, were obtained. The latter values were similar to sigma's (0.88 +/- 0.01) determined by lymph analysis in five additional forelimbs. We conclude that hemolysis results in overestimates of sigma. After hemolysis correction, this technique yields similar results to those obtained from lymph analysis for the forelimb and from published values for the LLL.

Isoproterenol and aminophylline reduce lung capillary filtration during high permeability

1979 ◽  
Vol 46 (1) ◽  
pp. 146-151 ◽  
Author(s):  
T. Foy ◽  
J. Marion ◽  
K. L. Brigham ◽  
T. R. Harris
Keyword(s):  
Plasma Protein ◽  
Protein Concentration ◽  
Lymph Flow ◽  
High Permeability ◽  
Plasma Protein Concentration ◽  
Lung Fluid ◽  
Lung Fluid Balance ◽  
Lung Lymph ◽  
Lung Vascular Permeability ◽  
Lung Lymph Flow

Pseudomonas bacteremia in sheep causes a prolonged increase in lung vascular permeability to protein. Isoproterenol and aminophylline could effect lung fluid balance after Pseudomonas by reducing vascular pressures or by blocking release of permeability mediators. We measured vascular pressures, lung lymph flow, and lymph and plasma protein concentrations in unanesthetized sheep under baseline conditions and during steady-state increased permeability after Pseudomonas. Pseudomonas caused pulmonary vascular pressures to rise and lung lymph flow to increase fivefold, but lymph/plasma protein concentration did not change. Pulmonary vascular pressures and lung lymph flow decreased during intravenous infusion of isoproterenol and aminophylline. The decrease in lymph flow after isoproterenol and isoproterenol plus aminophylline was linearly related to the decrease in microvascular pressure (r = 0.71). Lymph/plasma total protein concentration ratios and lymph clearance of proteins with molecular radii 36--96 A remained high during isoproterenol and aminophylline. These drugs can substantially reduce transvascular filtration primarily because they reduce lung vascular pressures.

EFFECT OF ADRENOCORTICOTROPIC HORMONE (ACTH) AND CORTISONE ON PROTEINURIA AND HEMATURIA IN THE NEPHROTIC SYNDROME

PEDIATRICS ◽  
1955 ◽  
Vol 15 (1) ◽  
pp. 49-53
Author(s):  
Walter Heymann ◽  
Caroline Gilkey ◽  
Milena Salehar
Keyword(s):  
Nephrotic Syndrome ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Adrenocorticotropic Hormone ◽  
Hormone Treatment ◽  
Oncotic Pressure ◽  
Plasma Protein Concentration

1. Fifteen children suffering from the nephrotic syndrome were treated with 22 courses of either ACTH or cortisone. Three children failed to have a diuresis during 4 courses of treatment. No decrease in proteinuria was noted. Eighteen courses of hormone treatment resulted in diuresis in 12 patients. A decrease in proteinuria preceded diuresis in each instance. [See Table II, Fig. 2 and Fig. 3 in Source Pdf] 2. A relationship between severity of hypoproteinemia and onset of diuresis, once proteinuria has started to decrease, has been established. 3. It is concluded that one of the important actions of ACTH or cortisone in inducing diuresis is concerned with the decrease in proteinuria, resulting in increasing plasma protein concentration and oncotic pressure. 4. The effect of these hormones on hematuria in nephrosis has been noted during 4 courses of treatment. In these proteinuria decreased appreciably. In 4 instances hematuria persisted and proteinuria decreased only slightly or not at all.

Effect of hypoproteinemia on lung fluid balance in awake newborn lambs

1986 ◽  
Vol 61 (3) ◽  
pp. 1139-1148 ◽  
Author(s):  
T. A. Hazinski ◽  
R. D. Bland ◽  
T. N. Hansen ◽  
E. G. Sedin ◽  
R. B. Goldberg
Keyword(s):  
Plasma Protein ◽  
Fluid Balance ◽  
Left Atrial ◽  
Protein Concentration ◽  
Lymph Flow ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Plasma Protein Concentration ◽  
Lung Fluid ◽  
Lung Lymph

To study the influence of plasma protein concentration on fluid balance in the newborn lung, we measured pulmonary arterial and left atrial pressures, lung lymph flow, and concentrations of protein in lymph and plasma of eight lambs, 2–3 wk old, before and after we reduced their plasma protein concentration from 5.8 +/- 0.3 to 3.6 +/- 0.6 g/dl. Each lamb underwent two studies, interrupted by a 3-day period in which we drained protein-rich systemic lymph through a thoracic duct fistula and replaced fluid losses with feedings of a protein-free solution of electrolytes and glucose. Each study consisted of a 2-h control period followed by 4 h of increased lung microvascular pressure produced by inflation of a balloon in the left atrium. Body weight and vascular pressures did not differ significantly during the two studies, but lung lymph flow increased from 2.6 +/- 0.1 ml/h during normoproteinemia to 4.1 +/- 0.1 ml/h during hypoproteinemia. During development of hypoproteinemia, the average difference in protein osmotic pressure between plasma and lymph decreased by 1.6 +/- 2 Torr at normal left atrial pressure and by 4.9 +/- 2.2 Torr at elevated left atrial pressure. When applied to the Starling equation governing microvascular fluid balance, these changes in liquid driving pressure were sufficient to account for the observed increases in lung fluid filtration; reduction of plasma protein concentration did not cause a statistically significant change in calculated filtration coefficient. Protein loss did not influence net protein clearance from the lungs nor did it accentuate the increase in lymph flow associated with left atrial pressure elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of arachidonic acid and indomethacin on renal function of dogs with pericardial tamponade

1981 ◽  
Vol 59 (6) ◽  
pp. 586-594 ◽  
Author(s):  
Robert J. Boudreau ◽  
Henry Mandin
Keyword(s):  
Blood Flow ◽  
Arachidonic Acid ◽  
Arterial Pressure ◽  
Plasma Protein ◽  
Sodium Excretion ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Pericardial Tamponade ◽  
Renin Activity ◽  
Plasma Protein Concentration

Previous studies revealed persistent sodium retention in dogs with chronic pericardial tamponade (induced by injection of Freund adjuvant into pericardial sacs) and pericardiocentesis, revealed in increased sodium excretion. Three groups of dogs were studied. Group 1 was treated with indomethacin (2.5 mg/kg, iv) prior to pericardiocentesis. Compared with experiments without indomethacin, sodium excretion did not increase following pericardiocentesis in animals treated with indomethacin despite similar changes in arterial pressure, venous pressure, hematocrit, plasma protein concentration, and renin activity. This effect of indomethacin was presumably mediated through prostaglandin (PG) synthesis inhibition. Group 2 dogs received an infusion of arachidonic acid (AA) (to increase PG synthesis) into the left renal artery (20 μg∙kg−1∙min−1). Sodium excretion increased after AA infusion during tamponade (11.2 to 30.9 mequiv∙min−1) with a further increase occurring after pericardiocentesis (84.4 mequiv.∙min−1). Animals in group 3 were infused with both 20 and 80 μg∙kg−1∙min−1 doses of AA. Although sodium excretion following 80 μg∙kg−1∙min−1 AA (21 mequiv.∙min−1) was higher than that seen during 20 μg∙kg−1∙min−1 (14.2 mequiv.∙min−1), a further increase in sodium excretion to 45.6 mequiv.∙min−1 followed pericardiocentesis. During tamponade, AA did not change any of the measured parameters other than sodium excretion, a result compatible with the proposed distal tubular site of action of PG. Absolute but not fractional cortical blood flow distribution increased during the time sodium excretion increased following pericardiocentesis in all experiments. It is proposed that increased PG synthesis may be one possible mechanism involved in the natriuresis seen following pericardiocentesis. One cannot exclude the possibility that increased absolute blood flow to the superficial cortex also contributes to the observed natriuresis. Changes in arterial pressure, venous pressure, hematocrit, plasma protein concentration, and renin activity appear to contribute to the observed natriuresis but only when PG synthesis is not blocked.

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