Studies on Ultrafiltration in Peritoneal Dialysis: Influence of Plasma Proteins and Capillary Blood Flow

1986 ◽  
Vol 6 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Claudio Ronco ◽  
Alessandra Brendolan ◽  
Luisa Bragantini Stefano ◽  
Chiaramonte Mariano ◽  
Feriani Aldo Fabris ◽  
...  
Keyword(s):  
Blood Flow ◽  
Peritoneal Dialysis ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Transmembrane Pressure ◽  
Ultrafiltration Rate ◽  
Filtration Fraction ◽  
Plasma Protein Concentration

This study has evaluated the influence of peritoneal blood flow and plasma protein concentration on the peritoneal ultrafiltration rate. In vitro and in vivo experiments were done to assess the effective peritoneal capillary blood flow. Based on the assumption that one can compare the behavior of an hollow fiber hemofilter with the peritoneal dialysis system, we have compared the opera tional characteristics of the two systems. After demonstrating that there was filtration pressure equilibrium in the filter, the plasma protein concentration was measured in the venous site of the filter at different applied transmembrane pressures. The nomogram, so obtained, was used to calculate the plasma-protein concentration in the blood leaving the peritoneal capillary during exchanges with an established glucose concentration (and therefore at a given transmembrane pressure), and to calculate the filtration fraction. Once that fraction had been calculated, based on the value of the ultrafiltration rate, one can calculate the importance of the plasma flow and then the blood flow. In this study the filtration fraction ranged between 45 and 55% and the blood flow ranged between 21 and 27 ml/min. It was concluded that the blood flow may be very low and hence may limit ultrafiltration.

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.

Backdiffusion or Bicarbonate May Stimulate Complement Activation during Haemodialysis with Low-Flux Membranes

1994 ◽  
Vol 17 (3) ◽  
pp. 131-136 ◽  
Author(s):  
L Lundberg ◽  
B.G. Stegmayr ◽  
B. Wehle
Keyword(s):  
Plasma Protein ◽  
Complement System ◽  
Hollow Fiber ◽  
Protein Concentration ◽  
Transmembrane Pressure ◽  
Plasma Protein Concentration ◽  
Blood Samples ◽  
Group I ◽  
Group Ii ◽  
The Complement System

Backdiffusion of dialysate during haemodialysis with low-flux membranes and the use of bicarbonate dialysatebase, may increase the risk for contamination. The influence on the complement system was studied by altering the flux of acetate or bicarbonate dialysate base across the membrane. Eight patients were dialysed with a transmembrane pressure of 100 mm Hg (group I) during the first 60 min to standardize the ultrafiltration (UF) and acetate as dialysate. In eight other patients (group II) the UF was “set at zero” ml during the first 60 min using an FCM 10-1 monitor (Gambro) and bicarbonate as base. The groups were dialysed three times on two hollow-fiber membranes made of Hemophan® and cellulose acetate (CA). Blood samples were taken at 0, 15, 60 and 180 min, and analysed for plasma protein, haematocrit and complement C3d. In group II there was a reduction in plasma protein concentration at 15 and 60 min (p<0.002) for Hemophan and at 60 min (p<0.01) using CA. C3d was increased at 15 min for both filters (p<0.03). The reduction of protein in group II was followed by changes in the haematocrit, indicating a backdiffusion of dialysate, which may contribute to the concomittant increase in C3d.

Fluid uptake in the renal papilla by vasa recta estimated by two methods simultaneously

1985 ◽  
Vol 248 (3) ◽  
pp. F347-F353 ◽  
Author(s):  
B. Zimmerhackl ◽  
C. R. Robertson ◽  
R. L. Jamison
Keyword(s):  
Blood Flow ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Conversion Function ◽  
Plasma Protein Concentration ◽  
Micropuncture Technique ◽  
Fluid Uptake ◽  
Vasa Recta ◽  
Capillary Fluid

Fluid uptake by vasa recta was determined by two independent methods, videomicroscopy and the micropuncture technique, in the exposed papilla of nine antidiuretic rats to reconcile differences in values previously obtained by the two techniques. Erythrocyte velocity (Vrbc) and diameter (D) in descending vasa recta (DVR) (n = 22) and ascending vasa recta (AVR) (n = 31) near the "base" of the papilla were measured. Using a conversion function determined in vitro, Vrbc was transformed into mean blood velocity (Vblood). From D and Vblood, mean blood flow (Q) in DVR and AVR was calculated. In DVR, mean Vrbc, D, and Q were 1.06 +/- 0.01 mm/s, 16.3 +/- 0.4 micron, and 10.6 +/- 1.4 nl/min, respectively. In AVR, each corresponding value differed significantly, 0.47 +/- 0.06 mm/s (P less than 0.001), 19.8 +/- 0.8 micron (P less than 0.001), and 5.65 +/- 1.3 nl/min (P less than 0.025), respectively. Blood samples from DVR and AVR were obtained by micropuncture from the same location. Plasma protein concentration (g/dl) was 5.1 +/- 0.6 in DVR, 4.0 +/- 0.4 (P less than 0.05) in AVR, and 3.6 +/- 0.3 (P less than 0.025) in the renal vein. Assuming no net transcapillary loss of protein, total plasma outflow exceeded inflow by 29%, the excess representing fluid uptake; and to reconcile the blood flow and plasma protein concentrations found, functioning AVR should outnumber functioning DVR by a ratio of 2.1-2.4 to 1, depending on local hematocrit. Given the total number of AVR + DVR = 2,944 (at the base), capillary fluid uptake was calculated to range between 1.5 and 2.6 microliter/min.

Cardiac edema in dogs: Distribution of renal blood flow and glomerular filtrate

1979 ◽  
Vol 57 (1) ◽  
pp. 71-77
Author(s):  
Robert J. Boudreau ◽  
Henry Mandin
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Filtration Rate ◽  
Pericardial Tamponade ◽  
Plasma Protein Concentration ◽  
Glomerular Filtrate

The injection of Freund's adjuvant into the pericardial sac of 29 dogs resulted in chronic pericardial tamponade with persistent sodium retention. Micropuncture, clearance, and radioactive microsphere experiments were initiated 6–13 days after pericardial injection and 60 min after pericardiocentesis. Pericardiocentesis increased sodium excretion (from 12.2 to 41.3 μequiv./min) and mean arterial pressure (+ 20 mmHg (1 mmHg = 133.322 Pa)). Central venous pressure decreased 6.5 mmHg, as did hematocrit (from 45.7 to 39.8%) and plasma protein concentration (from 5.88 to 5.15 g%). Pericardiocentesis had no significant effect on renal blood flow (RBF), nor plasma flow. Redistribution of glomerular filtrate was suggested by the observation that superficial nephron glomerular filtration rate increased (from 91 to 108 nL/min) while glomerular filtration rate remained unaltered. Determination of intrarenal distribution of RBF revealed that cortical blood flow also distributed superficially. A significant increase in the fraction of RBF perfusing zone 1 (outer cortex) and a decrease in fractional perfusion of zones 2, 3, and 4 (juxtamedullary cortex) were observed in each experiment following pericardiocentesis. RBF distribution examined in a series of six animals prior to and during the development of pericardial tamponade showed the opposite effect.These results indicate that pericardiocentesis causes redistribution of both glomerular filtrate and RBF to superficial nephrons. The development of pericardial tamponade was associated with increased fractional juxtamedullary blood flow. These changes may have been the result of altered blood pressure, hematocrit, plasma protein concentration, or altered renal resistance.

Importance of the liver during glucagon-mediated increases in canine renal hemodynamics

1985 ◽  
Vol 249 (2) ◽  
pp. F319-F322 ◽  
Author(s):  
A. J. Premen
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Protein Concentration ◽  
Filtration Rate ◽  
Filtration Fraction ◽  
Plasma Protein Concentration ◽  
Order Of Magnitude ◽  
Anesthetized Dogs ◽  
Arterial Plasma ◽  
Intraportal Infusion

We ascertained the importance of the liver in mediating glucagon-induced increases in renal blood flow (RBF) and glomerular filtration rate (GFR) by comparing the renal hemodynamic responses to intrarenal versus intraportal infusion of glucagon at 3 ng X kg-1 X min-1 (a dose previously considered "physiologic") in two separate sets of anesthetized dogs. Following intrarenal infusion for 60 min (n = 6), glucagon was without effect on RBF and GFR. On the average, RBF and GFR increased by only 2 +/- 1 and 3 +/- 1%, respectively. However, in a second group of dogs (n = 6), intraportal infusion of glucagon significantly increased both RBF and GFR by the same order of magnitude over 60 min. RBF and GFR increased, on the average, by 22 +/- 2 and 20 +/- 2%, respectively. Peak responses occurred 30 min following glucagon infusion when RBF and GFR were elevated by 25 +/- 2 and 26 +/- 2%, respectively. In neither group of dogs were filtration fraction, arterial pressure, heart rate, arterial hematocrit, or arterial plasma protein concentration altered. These data indicate that the liver plays an important role in mediating the renal hyperemia and hyperfiltration observed following a physiologic infusion of glucagon.

Effect of renin, ischemia, and plasma protein loading on the isolated perfused kidney

1965 ◽  
Vol 209 (4) ◽  
pp. 835-843 ◽  
Author(s):  
Sheldon Rosenfeld ◽  
Roy Kraus ◽  
Avile McCullen
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Plasma Protein ◽  
Artificial Heart ◽  
Protein Concentration ◽  
Rabbit Kidney ◽  
Slight Reduction ◽  
Isolated Kidney ◽  
Plasma Protein Concentration ◽  
Pressure Changes

Normal renal function has been maintained in an isolated artificial heart-lung, whole-blood perfused rabbit kidney for periods of 2–4 hr. The isolated kidney responds to changes in perfusion pressure, changes in plasma protein concentration, and exposure to a 10-min period of ischemia, in a manner similar to that described for the kidney of the normal intact animal. Elevation of the plasma protein concentration produces a fall in the rate of urine flow, sodium excretion, and creatinine clearance, and a marked proteinuria. The administration of renin produces a marked diuresis, natriuresis, and proteinuria. This effect is also produced by the exposure of the isolated kidney to a 10-min period of ischemia, suggesting that this response may be mediated by a renin mechanism. The responses of the kidney to these two procedures differ only in that ischemia produces an increase in renal blood flow and renin produces a slight reduction in renal blood flow and a more pronounced proteinuria.

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Ocular Blood Flow ◽  
Capillary Blood ◽  
Post Treatment ◽  
Capillary Blood Flow ◽  
Doppler Imaging ◽  
Retinal Capillary

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.

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