Evaluation of plasma neurotoxin concentration in uraemic polyneuropathic patients

Purification of b4-2 sub-peak obtained on DEAE Sephadex A25 chromatography gave us the possibility of quantifying the plasma concentration of the neurotoxin present in uraemic patients with active polyneuropathy. From the purified neurotoxin isolated by kieselguhr and cellulose chromatography we calibrated analytic columns for b4-2 analysis. Plasma concentration, measured in 6 uraemic neuropathic patients, is between 13 and 19 mg/litre. In 52 uraemic patients without neuropathy, the plasma concentration is between 3 and 9 mg/litre. In 20 healthy subjects the plasma concentration is less than 1 mg/litre. The weekly neurotoxin removal in uraemic patients without neuropathy, treated by a five hours RP6 session 3 times a week, is of the same order of magnitude as the weekly urinary excretion in healthy subjects. Preliminary results of a tentative identification of this purified product indicate that it is not a polypeptide but an acid-polyol with carbohydrate structure.