Bilirubin Adsorption Research Articles

The binding of bilirubin by immobilized oligopeptides containing lysine

Peptides consisting of portions of the sequence Arg-(Lys)2-(Ser)2-Lys-(Ala)3 have been immobilized onto a polyacrylamide support by solid phase peptide synthesis. Isotherms at 0 °C for the adsorption of bilirubin from phosphate buffer by these peptide resins are highly dependent on pH, in the range 7.80–11.00, demonstrating the importance of ionic interactions. The adsorption behaviour of bilirubin-related tetrapyrroles shows that structural factors also influence the process. Peptide resins containing two or more residues of lysine have two binding sites on each pendant and are characterized by positive cooperativity, to a degree that is highly dependent on the number of residues. It is proposed that bilirubin molecules bound by lysine-containing pendants are stacked, the dimer state being stabilized by π-π electron interactions, hydrogen bonds, and hydrophobic interactions. Site binding constants show that arginine-containing pendants manifest a stronger affinity for bilirubin. Keywords: bilirubin, adsorption, lysine, oligopeptides, cooperativity.

Polymer resins with amino acid containing pendants for sorption of bilirubin. IV. Site binding constants.

Site binding constants, calculated for the adsorption of bilirubin onto various lysine, arginine, or histidine containing oligopeptide-resins assuming either a one or two site binding model, are of the order of 10(4) M-1. Using these data it can be shown that there are positive cooperative effects for lysine-containing pendants, while arginine-containing pendants eventually result in negative cooperative behaviour. This difference in behaviour has been attributed to the difference in the side groups in the arginine and lysine pendants and is discussed in terms of the basicity of the amino acids, accessibility to the sites as a consequence of the flexibility or rigidity of the side group, and in terms of pi-pi electron interactions, where applicable.

A simplified analysis of Scatchard plots for systems with two interacting binding sites.

AbstractA simple graphical method for calculating stoichiometric and site binding constants for systems with two initially equivalent interacting sites is derived from a modified Scatchard equation. The binding constants can be calculated from Scatchard plots (r/[A] as a function of r) using the values of r/[A] (r is the molar ratio of bound ligands to total protein and [A] is the equilibrium concentration of free ligand) when r = 0 and r = 1 (half‐saturation). The applicability of the method to the adsorption of bilirubin by peptide pendants immobilized on a polyacrylamide support is demonstrated.

Interaction of bilirubin with human lymphocytes and granulocytes--the effect on bilirubin metabolism.

An in vitro degradation of bilirubin by isolated human granulocytes and lymphocytes is described. Changes in the bilirubin concentration during interaction with these cells were determined spectrophotometrically. The dependence of the reaction velocity on the original bilirubin concentration followed an adsorption isotherm, typical of enzyme processes with a Km of 79 microM at a cell concentration of 500/microL. The primary event is the adsorption of bilirubin to the cell surface and, in addition, its detoxication. Cyanide and sonic treatment of cells inhibit the reaction, salicylic acid enhances the cell activity. The bilirubin-detoxicating effect is discussed with respect to the therapy of hyperbilirubinaemia in neonates.

Removal of Unconjugated Bilirubin by Macroreticular Resin in Hemoperfusion

Macroporous polystyrene and polyvinylpyridine beads with quaternary ammonium and tertiary groups were tailor-made for the adsorption of unconjugated bilirubin. In vitro studies in order to obtain high adsorption capacity, the synthesized macroporous resin should have an average pore size of about 160 A and with surface area as large as possible. As the crosslinking of the resin increased from 4%-40% the amount of bilirubin adsorbed increased from 0.17 mg/g to 2.0 mg/g. Resins containing strong basic groups have higher adsorption capacities than their corresponding weak base groups. Adsorption mechanism studies showed that both chemical and physical adsorption took place. Adsorption of bilirubin in plasma was some what lower than in buffer solution.

Development of polyetherurethane sheet embedded with powdered charcoal for use in hemoperfusion.

This article describes the development of a polyetherurethane sheet embedded with powdered charcoal ( UPC ) for use in a hemoperfusion system. The UPC was 200 micron thick and the release of microparticles could be limited. The powdered charcoal used was selected for optimum pore size distribution and particle size (10-40 micron) to provide a maximum adsorption of bilirubin. The results of an in vitro adsorption test with this material showed an adsorption of bilirubin approximately 14 and 6 times higher than those by bead-type charcoal and XAD-7, respectively. Jaundiced dogs were subjected to direct hemoperfusion through a UPC column containing 36 g powdered charcoal. Effective decreases in bilirubin were observed, giving the maximum removal amounts of 78% in conjugated bilirubin and 76% in unconjugated bilirubin.

Preparation of a biocompatible albumin-coated ion exchange resin for bilirubin removal from the blood of jaundiced newborns.

Removal of bilirubin by hemoperfusion with ion exchange resin particles is suggested to replace exchange transfusion of blood of jaundiced infants in some cases of unconjugated hyperbilirubinemia. The hemoperfusion system developed here consists of a packed bed of a macroreticular resin which is made biocompatible by a coating of a monomolecular layer of albumin. The choice of the appropriate ionic form of the resin and the proper albumin coating and crosslinking procedure assures a high bilirubin adsorption capacity and excellent blood compatibility of the resin. The albumin coated resin removes in vitro 80-90% of the bilirubin initially present in the plasma. The results encourage in vivo clinical studies.

The Adsorption of Bilirubin from Aqueous Solution onto Solid Cholestyramine and Polyvinylpyrrolidone

Shifts in the visible spectrum of aqueous bilirubin (BR) resulting from the addition of soluble polyvinylpyrrolidone (PVP) suggest specific interactions. Hence, isotherms were determined for the adsorption of BR from aqueous solution onto solid, cross-linked PVP and onto cholestyramine (CA) (used as a reference adsorbent) at 0, 10, 20 and 25 degrees C. Although adsorption onto PVP reaches equilibrium values more rapidly than for CA, the latter adsorbent has a larger capacity. Furthermore the isotherms for PVP are independent of temperature while those for CA show an increase in BR adsorbed with an increase in temperature.

Bilirubin adsorption in vitro by foetal and adult human erythrocytes.

Adsorption of bilirubin in vitro by human foetal erythrocytes from umbilical cords was significantly greater than the binding by adult erythrocytes. A difference in binding capacity was detected at 0.6 mmol/l bilirubin concentration (bilirubin/albumin ratio 2:1) immediately after mixing with the bilirubin solution. After 30 min incubation a further increase in bound bilirubin was found to be due only to binding in foetal cells. The results suggest that bilirubin from the medium was incorporated into at least two compartments in foetal erythrocytes. A possible role of human foetal erythrocytes in bilirubin distribution to tissues is stressed.

From the Publishers

Previous articleNext article No AccessFrom the PublishersPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Elementary School Journal Volume 75, Number 4Jan., 1975 Article DOIhttps://doi.org/10.1086/460902 Citations: 1Citations are reported from Crossref Copyright 1974 The University of ChicagoPDF download Crossref reports the following articles citing this article:X. X. Zhu, G. R. Brown, L. E. St-Pierre Adsorption of Bilirubin with Polypeptide-Coated Resins, Biomaterials, Artificial Cells and Artificial Organs 18, no.11 (Jul 2009): 75–93.https://doi.org/10.3109/10731199009117290

Sephadex Adsorption of Bilirubin from Neonatal and Adult Serum

Abstract The bilirubin (BR)-binding capacity of albumin in serum from cord blood, as estimated by Sephadex gel filtration, is less than that of adult serum. The binding site at which BR is tightly bound by albumin in pools of infant serum was saturated at an average BR/albumin molar ratio of 0.66, while in adult serum the ratio was 1.00. With further increase in BR concentration, albumin of infant serum bound BR less than that of adult serum. These findings appear to have clinical significance with respect to the danger of BR encephalopathy in icteric infants.

THE ADSORPTION OF BILIRUBIN BY SEPHADEX AND ITS RELATIONSHIP TO THE CRITERIA FOR EXCHANGE TRANSFUSION

Small quantities of bilirubin (BR) were adsorbed by specially preparedh small columns of Sephadex G-25 from artificially jaundiced sera. The amount of bilirubin adsorbed from sera with bilirubin-albumin molar ratios between 1 and 2 was linearly related to the bilirubin concentration of the serum. There was no demonstrable adsorption of bilirubin by the column at ratios below 1. Sephadex columns may be of value in determining the time when exchange transfusion should be performed to prevent kernicterus.

Tritiated bilirubin: preparation and physiological studies.

A procedure is described for the preparation of tritiated bilirubin by the Wilzbach technique, either directly (preparation W) or in conjunction with irradiation from a Co60 source (preparation C-W). After equilibration of the preparations with polar and nonpolar solvents to remove labile tritium and repeated precipitation, the constant specific activities were 110 µc/mg (W) and 30 µc/mg (C-W), respectively. Radiochemical purity of the bilirubin-H3 preparations and their azobilirubin-H3 derivatives was demonstrated by paper chromatography. Bilirubin-H3 and a high dose of carrier bilirubin were injected simultaneously into rats and the comparative bilirubin levels in serum and bile were determined by radioactivity and colorimetric methods. After 75 min, 20–30% of the initial label remained in the serum as nonbilirubin radioactivity. Pre-equilibration in vitro of bilirubin-H3 with albumin removed the protein-labile tritium. It was concluded that the adsorption of bilirubin to serum protein may involve hydrogen binding at an aliphatic group on the bilirubin molecule. In serum and bile the distribution of the bilirubin-H3 (pre-equilibrated with albumin in vitro) was identical to the distribution of bilirubin measured colorimetrically. The half-life for disappearance of bilirubin from serum in these rats was 25–35 min.