The study of Heafield et al. (1990) has prompted us to compare the lev
els of sulfate cysteine and homocysteine in the plasma of healthy subj
ects and of patients with Parkinson's disease treated by L-Dopa and do
pa decarboxylase inhibitors. The levels of sulfate and cysteine in the
plasma of controls and patients with Parkinson's disease were not sta
tistically different but the level of homocysteine was higher in patie
nts. (C) 1995 Intox Press, Inc.