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The sites of destruction of 51Cr tagged G-6-PD deficient red cells in normal and primaquine sensitive Sardinians after drug administration have been studied by means of surface monitoring and, in one case, by direct quantitation after surgery. In practically all cases a liver to spleen ratio of one could be recorded, with a constant splenic participation in the uptake of radioactivity. It was observed that, beside the major role played by the liver in the sequestration and disposal of severely damaged G-6-PD deficient red cells after administration of primaquine, also the spleen has a significant share in the disposal of damaged cells.

Muscle exchange of amino acids (AAs) was evaluated by using the arteriovenous-difference technique across the leg in seven patients with chronic renal failure (CRF) and eight control subjects before and for 75 min after the ingestion of an AA mixture simulating an animal-protein meal. Total AAs increased in arterial blood much more in patients with CRF after AA ingestion than in control subjects, as a consequence of an exaggerated increase in nonessential AAs (NEAAs) (+127%). Moreover, total AAs were taken up by the leg in larger amounts than in control subjects (+71%, P < 0.0025) because of increased uptake of NEAAs (+156%, P < 0.005). Branched-chain AA uptake by the leg was, in absolute values, similar to that of control subjects ; however, because of the increased uptake of total AAs, branched-chain AA uptake was only 30% of total AA extraction, compared with 46% in control subjects. Abnormalities in AA uptake by muscle paralleled those in arterial AAs. In fact the same AAs that increased abnormally in blood were taken up by the leg at higher rates than in control subjects. Variations in arterial concentrations and muscle uptake of AAs were inversely related to arterial bicarbonate concentration, suggesting a role for acid-base status in modifying both the arterial supply and muscle metabolism of AAs. Results indicate that in CRF patients the normal pattern of postprandial AA repletion is disrupted. Muscle tissue faces the increased and unbalanced postprandial supply of AAs with an augmented and unbalanced uptake. Data are consistent with an abnormal use of exogenous AAs in CRF patients, possibly induced by metabolic acidosis. Am J Clin Nutr 1995 ;62 :136-42.

We designed a new formula for AA supplement in order to correct blood pools of AA in chronic renal failure (CRF). This supplement was given to 5 patients with CRF and its effectiveness was tested during long term (12-24 weeks) administration. The patients had previously been on a diet providing 0.6 g of protein and 34-36 kcal/kg/day. The diet was then modified to one providing the same caloric content but only 0.3 g/kg high biological value protein per day with the addition of the AA supplement (0.3 g/kg). The new diet corrected most of the abnormalities in blood AA pools. After 1 month of treatment Val, Leu, Thr, Ser and Tyr levels rose and became normal throughout the study. Ratios Tyr/Phe, Ser/Gly and Val/Gly also improved. During the treatment no side effect or toxicity was observed, and serum albumin, transferrin and nutritional anthropometric parameters persisted to be normal. It is concluded that this specially designed AA supplement added to a hypoproteic diet is an acceptable regimen which can quite completely correct the imbalance in blood AA pools in CRF.

Part 1 Ammonia-forming enzymes: roles of hetero-enzyme complexes in acid-base balance, L.A. Fahien et al soluble and membrane-bound forms of phosphate-activated glutaminase with different kinetic characteristics in pig and rat kidney mitochondria, B. Roberg et al the increase in glutamine synthesis from glucose caused by ammonium chloride in rabbit kidney tubules does not involve an increase in citrate synthesis, M.-F. Chauvin et al. Part 2 Molecular biological aspects of glutamine metabolism: stimulation of phosphoenolpyruvate carboxykinase gene expression in cultured LLC-PK1-F+ cells, K. Drewnowska et al a novel Na+-dependent amino acid transporter with a high affinity to glutamine, H. Endou et al effect of K+ depletion on glutamate dehydrogenase, S. Sastrasinh et al characterization of the hepatic glutaminase promoter, M.-I. Chung-Bok and M. Watford. Part 3 Metabolic alterations in acidosis: ensuring a minimum urine flow rate during water deprivation in chronic fasting, M.L. Halperin et al role of adrenal steroids in stimulating ammonium excretion during acute metabolic acidosis, P.J. Nolan et al mechanism(s) regulating matrix pH in rat kidney mitochondria, K. Drewnowska and A.C. Schoolwerth. Part 4 Kidney and brain metabolism of glutamine and other amino acids: an overview of mitochondrial glutamine transport and phosphate-activated glutaminase in the kidney, E. Kvamme et al renal homocysteine metabolism, J.D. House et al metabolic requirement for inorganic phosphate by renal proximal tubules - influence upon "L"-glutamine metabolism, M.C. Chobanian et al. Part 5 Hepatic amino acid metabolism: hippurate as a source of renal and hepatic ammoniagenesis in different species, M. Malyusz et al regulation of hepatic protein degradation, E.F.C. Biommaart et al no increase of ornithine concentration in the liver of ornithine transcarbamylase-deficient spf-ash mice following intraperitoneal injection of ammonium chloride, T. Saheki et al nitrogen metabolism in ammonium chloride-supplemented rats during protein depletion, A.L. Lardner and D.J. O'Donovan. Part 6 Renal utilization of various nitrogenous substances: how does the kidney handle plasma polyamines?, M.E. Brosnan et al oxidation of glutamine in cancer cells and regeneration of adenylates via adenylosuccinate synthetase, Z. Kovacevic et al leucine metabolism and protein dynamics in the human kidney, G. Garibotto et al. Part 7 Interorgan metabolism of ammonia and other substrates: defective glycolysis and catabolism of protein and amino acids in skeletal muscle during metabolic acidosis, A. Bevington and J. Walls incorporation of 15N-labelled precursors into urea isotopomers, J.T. Brosnan et al RT-PCR localization of phosphoenolpyruvate carboxykinase in the proximal tubule of the rat during metabolic acidosis, M.R. Craig et al.