[Concentration of middle-sized molecules in the blood of children with chronic renal failure during treatment with short-term hemodialysis].

Blood serum from children and young patients with chronic kidney insufficiency at the terminal step as well as from healthy donors was fractionated using ultrafilters "Amicon" XM-50 and Sephadex G-25. Three fractions were obtained: F1--molecular mass 50,000-5,000, F3--3,000-800 (fraction of middle mass molecules, MM) and F5 < 200. Amount of protein in the MM fraction exceeded 7-10-fold the protein content in the same fraction of donor blood serum.

[Effect of uremic serum and its fractions on stem cells in vivo].

Serum of 18 children and adolescents with chronic renal failure at the terminal stage of the kidney disease was fractionated on plates manufactured by Amicon Company and on Sephadex G-25. Uremic serum and ultrafiltrate with a molecular mass of 50,000 produced erythropoiesis inhibiting effect in polycythemic mice. However, the uremic serum and its fractions (50000--5000 and 3000--800) did not alter the number of microscopically visible colonies in the spleen of irradiated mice and their differentiation and proliferation compared to the mice that had received donor serum.