[Estimated structure of the polysaccharide related eye lesions, and biological actions of 4-O-methylaldobiouronic acid and it's partially acetylated derivative].

From November 1981 to March 1982, an outbreak of scleritis and/or iritis occurred among patients treated with a special series of hemodialyzers. Several works demonstrated that acetylated carbohydrate derivatives derived from hemicellulose played a primary role in the outbreak and that uronic acid residues were present in the carbohydrate derivatives. Based on these previous findings, we tried to clarify the structure of the polysaccharide causing eye lesions. Application of anion-exchange chromatography enabled us to isolate an acidic polysaccharide from the dialyzer extracts. We found that xylose (Xyl) and 4-O-methylglucuronic acid (4-O-Me-GlcA) were contained in the ratio of ca. 7:1 by gas chromatography (GC). The 13C-NMR spectrum of the polysaccharide was similar to 4-O-methylglucuronoxylan. From these experimental results, we estimated that the structure of the acidic polysaccharide was partly equivalent to xylans existing in the wood of gymnosperms. Then we directed our attention to the 4-O-Me-GlcA moiety. In order to evaluate the biological actions of this part structure, we prepared two kinds of related disaccharides; 4-O-methylaldobiouronic acid (4-O-Me-GlcA-Xyl) and partially acetylated 4-O-methylaldobiouronic acid (Ac 4-O-Me-GlcA-Xyl). These disaccharides were examined with rabbits, but no significant biological actions occurred.