Effect of blood purification on the kidney function of the jaundiced rat

Polylysine-immobilized chitosan beads as adsorbents for bilirubin

Hyperbilirubinemia generally relates to an elevated bilirubin level in the blood and is usually an indication of a disease of the blood, liver, or biliary tract. Hemoperfusion using synthetic resins as sorbents has been one of the ways to reduce bilirubin. In this study, chitosan, a natural polysaccharide having structural characteristics similar to glycosaminoglycans and which is nontoxic and biocompatible, has been used for bilirubin binding. Several layers of poly-L-lysine have been coated covalently onto chitosan beads, using N2 plasma and carbodiimide treatments. Such surface-modified chitosan beads exhibited high binding affinities for bilirubin (1.13 +/- 0.18 mg/g beads) in aqueous phosphate buffer solutions at 4 degrees C in relation to activated charcoal (0.74 +/- 0.2 mg/g). The polylysine-coated resins have been reported to have an improved binding affinity for bilirubin over cholestyramine. It seems that the surface-immobilized polylysine has an increased bilirubin binding affinity and is highly stable. The binding capacity is proportional to the amount of polylysine bonded to the chitosan beads. The hemolytic potential of all modified beads is compatible with polystyrene control tubes. Studies were also performed against albumin as proof of specificity toward bilirubin binding. The albumin-coated beads have shown the highest blood compatibility and selectivity over the other modified beads. However, it appears that polylysine-modified chitosan may be an excellent sorbent system for hemoperfusion due to its high binding affinity, capacity, and blood compatibility. Further studies are needed to determine its behavior under clinical conditions.

Renal function in obstructive jaundice in man: cholangiocarcinoma model

Renal function with respect to water clearance and renal hemodynamics was studied in 15 patients with obstructive jaundice due to cholangiocarcinoma. The results were compared with those of the control normal subjects. There was no change in renal function in the patients with mild to moderate jaundice, with total serum bilirubin from 8.0 to 15.1 mg/dl. Increased urinary sodium excretion and decreased free water and negative water clearances were observed in the patients with severe jaundice with total serum bilirubin from 27.0 to 40.4 mg/dl and normal serum albumin. Renal blood flow was normal, but creatinine clearance was decreased. In severely jaundiced patients with serum bilirubin from 30.5 to 40.1 mg/dl and hypoalbuminemia urinary sodium excretion, free water clearance, negative water clearance, renal blood flow and creatinine clearance were decreased. There was salt and water retention in this group. The findings suggest that in severe jaundice there is inhibition of sodium chloride reabsorption in the thick ascending limb of Henle's loop. ADH and increased hydraulic conductivity of the collecting tubules possibly contribute to decreased free water clearance. In severely jaundiced patients with hypoalbuminemia this salt losing effect is converted to salt retention by increased proximal tubular reabsorption of sodium.