Clinically Oriented Patient Maintenance Protocol: A Clinical Consensus of Experts.

The aim of the present survey was to define the most appropriate recall regimen and professional maintenance care protocol, identifying the main relative issues, based on a consensus of experts with long-term clinical experience. The survey consisted of 14 clinically relevant focused questions. The answers of each expert were aggregated to formulate clinical recommendations.

Blood-brain barrier permeability following traumatic brain injury.

Background: Brain edema and intracranial hypertension is deleterious after traumatic brain injury (TBI), but the underlying pathophysiology is complex and poorly understood. One major subject of controversy is the time course and extent of blood-brain barrier (BBB) dysfunction following trauma, and previous studies in humans have only provided semi-quantitative data. The objective of the present study was therefore to quantify changes in BBB-permeability in the early course of TBI, when brain edema is still evolving.

Two icodextrin exchanges per day in peritoneal dialysis patients with ultrafiltration failure: one center's experience and review of the literature.

Background: At present, only one exchange of an icodextrin-based solution is recommended to increase peritoneal ultrafiltration (UF) during long-dwell exchanges in peritoneal dialysis (PD) patients with impaired UF.

Aim: To review our experience with two icodextrin exchanges per day on net UF and body weight in PD patients with poor UF.

Methods: Data were analyzed on nine patients with poor UF on chronic PD who were given two icodextrin exchanges per day for 6 months and had various clinical and biochemical parameters assessed monthly.

The variability in ultrafiltration achieved with icodextrin, possibly explained.

Background: A recent study by Jeloka et al. (Perit Dial Int 2006; 26:336-40) highlighted the high variability in maximum ultrafiltered volume (UF(max)) and the corresponding dwell time (t(max)) obtained using 7.5% icodextrin solution.

The effects of low-sodium peritoneal dialysis fluids on blood pressure, thirst and volume status.

Background: Poor ultrafiltration is associated with worse outcomes in peritoneal dialysis (PD) patients. This might in part reflect problems associated with salt and water excess. Increasing the diffusive component of peritoneal sodium removal using low-sodium PD fluids might have beneficial effects on blood pressure (BP), thirst and fluid status that could translate into clinical benefits.

Effects of early endotoxemia and dextran-induced anaphylaxis on the size selectivity of the glomerular filtration barrier in rats.

This study was performed to investigate the glomerular permeability alterations responsible for the microalbuminuria occurring in endotoxemia and during anaphylactic shock. In anesthetized Wistar rats, the left ureter was catheterized for urine collection while, simultaneously, blood access was achieved. Endotoxemia was induced by lipopolysaccharide (LPS) from Escherichia coli, and glomerular permeability was assessed at 60 and 90 (n = 7) and 120 (n = 7) min.

Optimum electrolyte composition of a dialysis solution.

In patients undergoing peritoneal dialysis (PD) for end-stage renal failure, the optimum electrolyte composition of a dialysis solution is that which best serves the homeostatic needs of the body. Comparing the transperitoneal removal of electrolytes by conventional PD solutions (CPDSs) with that by normal kidneys, it is evident that peritoneal removal is in the lower range of what can be considered "normal." Given the electrolyte composition of CPDSs and a total dwell volume of 4 exchanges of 2 L each, approximately 90 mmol NaCl, 40 mmol K(+), 10 - 15 mmol HPO(4)(-) and 1 - 2 mmol Ca(2+) can be removed daily [plus 1 L ultrafiltration (UF)].

Fluid loss from the peritoneal cavity by back-filtration through the small pores of the three-pore model.

The partitioning of fluid flows among small and ultrasmall pores of the three-pore model in peritoneal dialysis has been traditionally assessed using 4-hour dwells with 3.86% glucose solutions. Under these conditions, however, back-filtration through small pores has been hard to demonstrate.

Glomerular sieving of three neutral polysaccharides, polyethylene oxide and bikunin in rat. Effects of molecular size and conformation.

Aim: Polysaccharides and many other non-protein polymers generally have a more open, flexible and asymmetrical structure compared with globular proteins. For a given molecular weight (MW), the Stokes-Einstein radius (a(e)) of the following polymers increases in the order: Ficoll < dextran View Article and Find Full Text PDF

Simulations of osmotic ultrafiltration failure in CAPD using a serial three-pore membrane/fiber matrix model.

Ultrafiltration failure (UFF) is a common complication of long-term peritoneal dialysis (PD). Functionally UFF is in most cases characterized by an enhanced peritoneal mass transfer area coefficient for glucose (PS(g)) combined with a largely unchanged peritoneal glucose osmotic conductance (L(p)Ssigma(g)). Morphologically, marked UFF occurs with fibrosis of the submesothelial zone in the peritoneum, combined with vasculopathy and vascular proliferation in deeper tissues.

Increased glomerular permeability to negatively charged Ficoll relative to neutral Ficoll in rats.

It is established that the glomerular filter sieves macromolecules based on their size, shape, and charge. Anionic proteins are thus retarded compared with their neutral or cationic counterparts. However, recent studies have indicated that charge effects are small, or even "anomalous," for polysaccharides.

Transvascular protein transport in mice lacking endothelial caveolae.

Caveolae are Omega-shaped vesicular structures postulated to play a role in transvascular protein transport. Studies on mice lacking endothelial caveolae, caveolin-1 knockout (Cav-1-KO) mice, indicate increased macromolecular transport rates. This was postulated to be due to the appearance of an alternative pathway.

Effects of glomerular filtration rate on Ficoll sieving coefficients (theta) in rats.

The purpose of the present study was to assess the role of diffusion and convection during filtration of Ficoll across the glomerular filter by comparing glomerular sieving coefficients (theta) to neutral fluorescein isothiocyanate (FITC)-Ficoll 70/400 obtained at low (hydropenic) vs raised (normal) glomerular filtration rates (GFRs). The theta for FITC-Ficoll was determined in anesthetized Wistar rats (304 +/- 18 g) following laparotomy and cannulation of the ureters, used for urine sampling. After surgery, GFR was 1.

A detailed analysis of sodium removal by peritoneal dialysis: comparison with predictions from the three-pore model of membrane function.

Background: The development of fluid and salt retention is a potential problem for all peritoneal dialysis (PD) patients. Sodium removal by the peritoneum is predominantly determined by convective fluid loss but influenced by diffusion and sieving due to free water transport as predicted by the three-pore model (TPM). The aim of the study was to establish the effect of transport status, dwell length and glucose concentration on observed ultrafiltration (UF), dialysate sodium concentration ([Na(+)](D)) and removal, and compare this with that predicted by a computer program based on the principles of the TPM.

Validation by computer simulation of two indirect methods for quantification of free water transport in peritoneal dialysis.

Background: In peritoneal dialysis, approximately 40% of the total osmotic ultrafiltration (UF) induced by glucose can be predicted to be due to "free" water transport across aquaporin-1 (APQ-1). Theoretically, it would be possible to assess the fraction of free water transport in the early phase of a hypertonic dwell, when UF rate is high and the relative contribution of Na+ diffusion is low. La Milia et al.

Ficoll and dextran vs. globular proteins as probes for testing glomerular permselectivity: effects of molecular size, shape, charge, and deformability.

Polydisperse mixtures of dextran or Ficoll have been frequently used as molecular probes for studies of glomerular permselectivity because they are largely inert and not processed (reabsorbed) by the proximal tubules. However, dextrans are linear, flexible molecules, which apparently are hyperpermeable across the glomerular barrier. By contrast, the Ficoll molecule is almost spherical.

Fluid and electrolyte transport across the peritoneal membrane during CAPD according to the three-pore model.

In the present review, we summarize the principles governing the transport of fluid and electrolytes across the peritoneum during continuous ambulatory peritoneal dialysis (CAPD) in "average" patients and during ultrafiltration failure (UFF), according to the three-pore model of peritoneal transport. The UF volume curves as a function of dwell time [V(t)] are determined in their early phase by the glucose osmotic conductance [product of the UF coefficient (LpS) and the glucose reflection coefficient (sigmag)] of the peritoneum; in their middle portion by intraperitoneal volume and glucose diffusivity; and in their late portion by the LpS, Starling forces, and lymph flow. The most common cause of UFF is increased transport of small solutes (glucose) across the peritoneum, whereas the LpS is only moderately affected.

Transvascular passage of macromolecules into the peritoneal cavity of normo- and hypothermic rats in vivo: active or passive transport?

During the last decades there has been a debate regarding whether transvascular protein transport is an active (transcytosis) or a passive (porous) process. To separate cooling-sensitive transcytosis from passive transport processes between blood and peritoneal fluid, we induced hypothermia in rats in vivo, reducing their body temperature to 19 degrees C. Control rats were kept at 37 degrees C.

Low-dose prostacyclin improves cortical perfusion following experimental brain injury in the rat.

It was recently shown that prostacyclin at a low dose reduces cortical cell death following brain trauma in the rat. Conceivably, prostacyclin with its vasodilatory, anti-aggregatory, anti-adhesive and permeability-reducing properties improved a compromised perfusion caused by post-traumatic vasoconstriction, microthrombosis and increased microvascular permeability. The objective of the present study was therefore to investigate the hemodynamic effects of low-dose prostacyclin in the traumatized rat cortex.

Mass transfer of calcium across the peritoneum at three different peritoneal dialysis fluid Ca2+ and glucose concentrations.

Background: In peritoneal dialysis, the rate of ultrafiltration has been predicted to be a major determinant of peritoneal calcium (Ca2+) removal. Hence, dialysis fluid glucose concentration should be an important factor governing the transperitoneal Ca2+ balance. The aim of this study was to test the effect of various dialysate glucose levels and selected dialysate Ca2+ levels on Ca2+ removal in peritoneal dialysis patients.

Glomerular filtration rate dependence of sieving of albumin and some neutral proteins in rat kidneys.

The size and charge-selective properties of the glomerular barrier are partly controversial. Glomerular sieving coefficients (theta) for proteins have rarely been determined noninvasively before in vivo. Therefore, theta was assessed vs.

Transendothelial transport: the vesicle controversy.

The relative contribution of transcytosis vs. large pore transport to the passage of macromolecules across microvascular endothelia has been a controversial issue for nearly half a century. To separate transcytosis from 'porous' transport, the transcytosis inhibitors N-ethylmaleimide (NEM) and filipin have been tested in in situ or ex vivo perfused organs with highly conflicting results.