特集：血液透析膜の最近の進歩 Ｈｉｇｈｌｙ ｐｅｒｍｅａｂｌｅ ｍｅｍｂｒａｎｅの溶質透過性の検討

Abstract

A few highly permeable dialysis membranes have been developed so far to remove beta-2-microglobulin having a molecular weight of 11, 800 that was identified as a new form of amyloid protein from patients on long-term hemodialysis. The present study is to evaluate the solute permeability for low molecular weight proteins such as beta-2-microglobulin of the highly permeable dialysis membranes by varying technical methods.The membranes tested included conventional and highly permeable dialysis membranes made of regenerated cellulose, and also highly permeable dialysis membranes of polysulfone and polyacrylonitrile as a reference. Solute permeability was determined by 1) the Wilson-plot method, 2) the microanalysis method with radioisotope-labeled solutes and 3) the photometric measurement. Test solutes were vitamin B12 beta-2-microglobulin, cytochrome-C and myoglobin.The highly permeable dialysis membranes of regenerated cellulose had higher surface porosities and pore sizes calculated from solute and pure water permeabilities and water content data that were practically the same as synthetic polymer membranes. This demonstrates that advanced membrane preparation techniques are capable of forming great surface porosity and large pore size on regenerated cellulose dialysis membranes.The Wilson-plot method is incapable of determination of diffusive permeability without ultrafiltration. Continuous measurements of optical density of a test solution in a hollow with optical fibers are well suited for precise determination of solute permeability by diffusion.The removed amount of beta-2-microglobulin calculated from solute permeability data of the most highly permeable dialysis membranes may not exceed the generated amount of beta-2-microglobulin.