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H Y Ton

Publications and source records attributed to H Y Ton.

6 recordsLinked to original sources
PubMed1979

Adsorption of human serum albumin to Amberlite XAD-7 resin.

In the present study the conditions leading to tight binding of human serum albumin to the Amberlite XAD-7 resin without the use of chemical coupling agents have been defined. Optimal binding (10.97 mm/kg dry XAD-7) was achieved at pH 5.0 and adsorption conformed to a Langmuir isotherm. Theoretical analysis of the data suggest adsorption of a monolayer of albumin which is supported by the absence of visual surface coating on scanning electron micrographs. Binding of human serum albumin was reduced when two chemical coupling agents, glutaraldehyde and carbodiimide were included in the human serum albumin solution, the elution of adsorbed HSA from the resins under severe flow conditions was reduced, and the amount eluted was minimal in all instances.

Acrylic Resins↗
PubMed1979

Albumin-coated Amberlite XAD-7 resin for hemoperfusion in acute liver failure. Part I: adsorption studies.

Platelets adhere to most foreign surfaces. As a result, polymers and albumin have been suggested as possible coatings to improve the blood compatibility of such surfaces. Amberlite XAD-7 has a high affinity for human serum albumin (HSA) and several protein-bound toxic metabolites. In the present study it is shown that HSA can be tightly bound to Amberlite XAD-7 without the use of chemical coupling agents. Optimal binding was achieved at pH 5.0 and the adsorption conforms to Langmuir's isotherm. Theoretical analysis of data and absence of a residual surface coating visible with scanning electron microscopy suggest a monolayer of albumin. The amount of HSA eluted from the resin under severe flow conditions was negligible (approximately 1%). Furthermore, in stirred batch studies with human plasma, the HSA coating did not decrease the adsorptive capacity of XAD-7 for bile acids and bilirubin.

Acrylic Resins↗
PubMed1979

Albumin-coated Amberlite XAD-7 resin for hemoperfusion in acute liver failure. Part II: in vivo evaluation.

Albumin-coated Amberlite XAD-7 has been previously shown to be blood compatible in in vitro hemoperfusion experiments whith human blood. In this study, the preliminary results are reported on single hemoperfusions with albumin-coated XAD-7 resin in four patients with acute liver failure. The mean platelet count was 116+/-SE 16.3% of the initial arterial value and the mean white cell count was 96+/-SE 6.5% of initial at the end of four hours of hemoperfusion. Removal of bilirubin, phenols and substances in the middle molecular weight range by the resin was demonstrated. These preliminary results suggest albumin-coated Amberlite XAD-7 resin to be blood compatible and capable of removing protein-bound and middle molecular weight substances from patients with acute liver failure. Further clinical evaluation of repeated resin hemoperfusion is required to determine whether this treatment will be beneficial to patient survival.

Acrylic Resins↗
PubMed1979

The use of prostacyclin, PGI2, in the prevention of platelet aggregation during charcoal haemoperfusion.

In previous studies severe side effects, including irreversible hypotension, platelet losses and rises in Swank screen filtration pressure, have been recorded during the treatment by charcoal haemoperfusion of patients with fulminant hepatic failure. It has also been demonstrated that rises in Swank screen filtration pressure in an in vitro test circuit are due to the presence of platelet aggregates. In this study Prostacyclin was infused at a constant rate, to give a blood concentration of 5 ng/ml, into the in vitro circuit just prior to the charcoal column. Rises in Swank screen filtration pressure were prevented, and it was also shown that the giving of a bolus dose of Prostacyclin (400 ng/ml blood concentration) reversed rises in Swank screen filtration pressure that have already occurred. On the basis of these findings, Prostacyclin would be expected to be of considerable clinical value in the prevention of adverse platelet reactions to charcoal haemoperfusion when carried out in patients with fulminant hepatic failure.

Adenosine Diphosphate↗
PubMed1978

The use of an in vitro haemoperfusion circuit to evaluate the blood compatibility of albumin-coated Amberlite XAD-7 resin.

We have developed an in vitro haemoperfusion circuit, which closely simulates the conditions encountered in a clinical haemoperfusion, for testing the blood compatibility of new adsorbent materials. Fresh heparinised human blood is perfused for 2 hours over two model columns arranged in parallel closed circuits. The present study was performed to investigate the blood compatibility of human serum albumin-coated Amberlite XAD-7 resin. Mean platelet losses over 2 hours were greater following perfusion of the uncoated resin (44 +/- SE 5.6%) than the albumin-coated resin (17 +/- SE 2.2%) (p less than 0.01). Mean white cell losses were similar (55%) for both resins. No rises in Swank screen filtration pressure, which detects the presence of cellular aggregates in blood, were observed. Coating of XAD-7 resin with HSA therefore improves its blood compatibility with respect to platelet losses and we thus intend to use this preparation in a clinical trial of resin haemoperfusion in fulminant hepatic failure.

Acrylic Resins↗