The plasma of uremic patients usually contains high concentrations of the so-called middle molecules (molecular mass, 300 to 1500 Da), which exert various toxic effects. Among these numerous substances, only one, named peak b4-2, has been correlated with uremic neuropathy. We describe our improvement of a two-stage chromatographic method, gel permeation followed by anion-exchange chromatography (J. Chromatogr. 146: 55-65, 1978), for separation and quantification of b4-2 in body fluids. In analyzing more than 300 samples from 43 uremic patients and 12 healthy subjects, we found a linear correlation between peak area at 254 nm and b4-2 concentration in the range 0.8 to 32 mg/L. The coefficient of variation, including data acquired during seven changes of columns, was 9%. Analysis time (80 min) was shorter than required with other methods. Our results confirm previous data for urinary b4-2 excretion by healthy subjects and for b4-2 removal rate in uremic patients undergoing hemodialysis or hemofiltration. Patients treated with continuous ambulatory peritoneal dialysis have a higher b4-2 excretion than do healthy subjects, suggesting a higher production of this solute in uremic patients.
A semi-automated two-stage chromatographic system is described for use in evaluating neurotoxin b4-2 in body fluids of uremic patients and healthy subjects. The only manual step is the injection, thus decreasing the risk of operator error inherent in the previous manual method (Clin Chem 29: 703-707, 1983) and concurrently improving CV from 9% to 6.4% as measured during a 16-month period.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations鈥揷itations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.