Determination of six pterins in urine by LC-MS/MS.

Background: The present work describes an analytical method for urinary pterins by LC-MS/MS, with emphasis on the separation of 6- and 7-positional isomers of bio- and neopterins.

Results: Urine sample preparation consisted of oxidation by MnO(2), filtration and direct dilution in the mobile phase. The method was validated in urine spiked at five concentration levels with true triplicates of each level.

Fumaric aciduria: an overview and the first Brazilian case report.

Fumaric aciduria is a rare metabolic disease, with 40 cases reported so far. Fumarase deficiency leads mainly to brain abnormalities, developmental delay, and great accumulation of fumaric acid in urine. This work presents the first case of fumaric aciduria described in Brazil, which presented with some interesting clinical and biochemical findings such as colpocephaly, hepatic alterations, and marked metabolic acidosis since birth.