Faculty Bibliography

Zymosan-activated neutrophils were found to incorporate large amounts of [3H]glucosamine into TCA-precipitable material as compared with resting cells. The burst of glucosamine incorporation began 2 min after zymosan exposure and lasted 3 to 5 min, after which the incorporation rate returned to that of resting cells. Studies with cells from patients with chronic granulomatous disease and hereditary myeloperoxidase deficiency as well as experiments with inhibitors indicated that glucosamine incorporation required both the respiratory burst and the myeloperoxidase system. SDS-polyacrylamide gel electrophoresis of [3H]glucosamine-containing TCA precipitates from zymosan-activated cells revealed radioactivity migrating throughout the length of the gel. The radioactivity in precipitates from resting cells or cells activated in the presence of a small amount of a myeloperoxidase inhibitor was found in a peak migrating close to the tracking dye. These results indicate that zymosan-activated neutrophils are able to incorporate glucosamine into protein by a process dependent on H2O2 and myeloperoxidase. The biosynthetic significance of this phenomenon is not certain, but it most likely represents the reaction of amino sugar with macromolecular degradation products formed by the action of the myeloperoxidase system on cellular and particulate constituents

Quantitative high-performance liquid chromatographic analysis of perbenzoylated sphingolipids has been used to study the correlations of body chemistry to clinical phenomena. Plasma sphingolipids were isolated from 32 Gaucher (beta-glucosidase deficiency) and six Fabry (alpha-galactosidase deficiency) patients by solvent partition and chromatographic separation on silicic acid columns. Plasma sphingolipids from a patient undergoing plasma-exchange were separated from interfering lipids with reversed-phase columns. Liquid-chromatographic analysis of sphingolipids provides useful supportive information for diagnoses because affected individuals are shown to possess increased circulating concentrations of the pathognomonic sphingolipid. We also used this technique to monitor sphingolipid concentrations in plasma and urine sediment during plasma exchange of a p atient with Fabry's disease. Regular plasma exchanges produced and maintained decreased concentrations of sphingolipids in plasma, but near pre-exchange concentrations were observed within days after the therapy was terminated

Carbohydrate metabolism was studied in 6 adult patients with phenylketonuria both on a low phenylalanine and an unrestricted institutional diet. Tolerance tests included PO glucose, PO phenylalanine, and combined glucose phenylalanine loading. Glucose, insulin, pyruvate, lactate, and phenylalanine were sampled at 0, 1/2, 1, 2, 3, and 4 hr. Fasting glucose levels were normal as were mean glucose values after challenge. Basal insulin secretion, as well as insulin response, to glucose challenge and to combined phenylalanine and glucose loading appeared normal. Insulin response to phenylalanine alone, however, was lower than expected in the phenylketonuria patients. Both off and on low phenylalanine diet, blood pyruvate and lactate were also normal. Thus, our data from blood did not show evidence of the abnormalities in glucose and pyruvate metabolism which have been proposed to occur in phenylketonuric patients but did not suggest that the potency of phenylalanine as an insulin secretagogue is diminished by chronic hyperphenylalaninemia