Search

Abstract: From the very beginning, the artificial kidney postponed the death of patients with end‐stage renal failure. For years, owing to the performance of the machine, the patient was obliged to follow a severe diet in order to maintain good humoral and circulatory status. Now technological improvements allow “dialysis à la carte,” whereby each individual achieves a better clinical status. The next step will be automation of the procedure to improve its security, mainly for dialysis performed at home.

Using a new dialysis membrane highly permeable to middle molecules and a closed loop dialysate delivery system, the author has tested the middle molecule hypothesis in a tentative way for understanding the uremic syndrome through hemodialysis.

In vitrobinding of 25-hydroxycholecalciferol (25-(OH)D3) and 1α,25-dihydroxycholecalciferol (1,25-(OH)2D3) was studied in the duodenal mucosa cytosol of rachitic rats: both 25-(OH)D3and 1,25-(OH)2D3bind to a macromolecule (sedimentation coefficient 5.5 to 6 S in low or high ionic strength) with a high affinity (KDat 4°C = 1.2×10−9mand 2×10−9m, respectively). In addition, it is concluded from competition and chase experiments that 25-(OH)D3binding sites differ from that for 1,25-(OH)2D3.

1. A method of measurement in vitro of purine biosynthesis de novo in human circulating blood lymphocytes is proposed. The rate of early reactions of purine biosynthesis de novo was determined by the incorporation of [14C]formate into N-formyl glycinamide ribonucleotide when the subsequent reactions of the metabolic pathway were completely inhibited by the antibiotic azaserine. 2. Synthesis of 14C-labelled N-formyl glycinamide ribonucleotide by lymphocytes was measured in healthy control subjects and patients with primary gout or hyperuricaemia secondary to renal failure, with or without allopurinol therapy. 3. The average synthesis was higher in gouty patients without therapy than in control subjects, but the values obtained overlap the normal range. In secondary hyperuricaemia the synthesis was at same value as in control subjects. 4. These results are in agreement with the inconstant acceleration of purine biosynthesis de novo in gouty patients as seen by others with measurement of [14C]glycine incorporation into urinary uric acid.