Poly-l-lysine modified cryogels for efficient bilirubin removal from human plasma.

In this study, poly-l-lysine (PLL) immobilized PHEMA cryogel was designed for the specific bilirubin removal from human plasma. The surface of PHEMA cryogels is surrounded by PLL chains to enhance specific binding of bilirubin molecules via specific complementary electrostatic interactions. The functionalization of the PHEMA cryogel was carried out by direct coupling of PLL to pre-activated OH-group of the HEMA alcohol units via carbodiimide activation. Prior to removal of bilirubin from human plasma, the optimization parameters including, initial bilirubin concentration, flow rate, temperature, ionic strength, and adsorption rates on adsorption of PLL-PHEMA cryogel were investigated from the aqueous medium. According to the elemental analyses results, the incorporation of PLL was 690.0 µmol/g cryogel. The cryogel has highly interconnected supermacroporous structure sized between 20 and 100 µm with a positive surface charge value. The maximum bilirubin adsorption capacity was found as 59.9 mg/g of the dry weight of PLL-PHEMA cryogel. Reusability study explored that PLL-PHEMA could be used with a negligible loss in the bilirubin adsorption capacity after successive ten adsorption-desorption cycles using the same adsorbent. The results of the study demonstrated that the PLL-PHEMA cryogel exhibited high specificity that can be used as an efficient column for removing the bilirubin from the human plasma.

The Biological Effects of Bilirubin Photoisomers.

Although phototherapy was introduced as early as 1950's, the potential biological effects of bilirubin photoisomers (PI) generated during phototherapy remain unclear. The aim of our study was to isolate bilirubin PI in their pure forms and to assess their biological effects in vitro. The three major bilirubin PI (ZE- and EZ-bilirubin and Z-lumirubin) were prepared by photo-irradiation of unconjugated bilirubin. The individual photoproducts were chromatographically separated (TLC, HPLC), and their identities verified by mass spectrometry. The role of Z-lumirubin (the principle bilirubin PI) on the dissociation of bilirubin from albumin was tested by several methods: peroxidase, fluorescence quenching, and circular dichroism. The biological effects of major bilirubin PI (cell viability, expression of selected genes, cell cycle progression) were tested on the SH-SY5Y human neuroblastoma cell line. Lumirubin was found to have a binding site on human serum albumin, in the subdomain IB (or at a close distance to it); and thus, different from that of bilirubin. Its binding constant to albumin was much lower when compared with bilirubin, and lumirubin did not affect the level of unbound bilirubin (Bf). Compared to unconjugated bilirubin, bilirubin PI did not have any effect on either SH-SY5Y cell viability, the expression of genes involved in bilirubin metabolism or cell cycle progression, nor in modulation of the cell cycle phase. The principle bilirubin PI do not interfere with bilirubin albumin binding, and do not exert any toxic effect on human neuroblastoma cells.

Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated.

[Effect of plant extracts from Baikal region on the choleretic reaction in white rats].

In the given work was estimated the choleretic activity of the extracts that was derived from the plants of the Baikal region. It had been shown that the experimental-therapeutic doses of the extracts stimulate choleretic reaction in intact rats.

Removal of protein-bound and unbound unconjugated bilirubin by perfusion of plasma through an anion-exchange resin in a case of Crigler-Najjar syndrome type I.

BACKGROUND: Patients with Crigler-Najjar syndrome, type I (CNS-I) have an inherited absence of hepatocellular bilirubin uridine diphosphate-glucuronosyltransferase activity, which results in severe unconjugated hyperbilirubinaemia, often causing kernicterus and death in infancy or childhood. METHODS: Our patient is a 19-year-old Japanese man with CNS-I diagnosed by the complete absence of the hepatocellular enzyme in a liver biopsy and genotyping. The efficacies of the removal of protein-bound (PBB) and unbound (UB) unconjugated bilirubin by phototherapy, plasma perfusion and liver transplantation were compared in the patient. RESULTS: At the age of 5 years, phototherapy treatment reduced the patient's PBB by 21% and UB by 34%, and 98% of the bilirubin produced daily was removed. At the age of 16 years, plasma perfusion combined with nightly phototherapy completely removed the daily production of bilirubin; however, by 24 h post-treatment, the PBB and UB were again increased. Apparently, these treatments were effective in reducing PBB and UB, but the effect was only temporary. Following liver transplantation, PBB and UB decreased to normal concentrations. CONCLUSIONS: Liver transplantation as a potential cure should be performed at a younger age, particularly in confirmed CNS-I cases for which reliable effects of phototherapy cannot be guaranteed.

Identification of a liver growth factor as an albumin-bilirubin complex.

We have reported the purification and characterization of a protein that behaves as a liver growth factor, showing activity either in vivo or in vitro [Díaz-Gil et al. (1986) Biochem. J. 235, 49-55]. In the present paper, we identify this liver growth factor (LGF) as an albumin-bilirubin complex. This conclusion is supported by the results of chemical and spectroscopic characterization of this protein as well as by experiments in vivo. Incubation of albumin isolated from normal rats with bilirubin/albumin molar ratios (r) resulted (when r = 1 or 2) in a complex with liver DNA synthesis promoter activity identical with that of LGF. The exact amount of bilirubin bound to albumin was assessed by fluorescence and c.d. spectra. This albumin-bilirubin complex showed the same dose-dependence profile as LGF either at low or high dose of protein injected per mouse. Both LGF and albumin-bilirubin complex produced similar increases in the mitotic index of mouse hepatocytes in vivo. A new mechanism for the onset of the hepatic regenerative process is proposed.

[Plasmaperfusion through activated charcoal and amberlite XAD-7 in dogs with liver failure induced by yellow phosphorus (author's transl)]. / Plasmaperfusion über Aktivkohle und Amberlite XAD-7 bei der phosphor-induzierten Lebernekrose des Hundes.

Various sorbents were tested in-vitro for their ability to support hepatic excretory and detoxification functions, and their in-vivo perfusion with plasma was studied in an animal experiment. Amino acids, particularly phenylalanine and tyrosine, were strongest bound by activated charcoal, while Amberlite XAD-7 removed conjugated and unconjugated bilirubin and bile acids from plasma. Using a cell-separator plasma of dogs, in whom acute liver failure was induced by yellow phosphorus, was perfused through a combination of charcoal and Amberlite XAD-7 without major complications. Platelet counts remained nearly unchanged, platelet aggregation was inhibited reversibly, and circulating platelet aggregates occurred late only. It is concluded that using the method described, therapeutic trials in patients with fulminant hepatic failure can be performed.