Improved synthesis of [1-14C]acyl-sphingosine-galactose-3-sulfate (sulfatide) for diagnosis of metachromatic leukodystrophy: usefulness of radioscanning.

We report an improved method for the radiolabelling of [1-14C 00acyl-sphingosine-galactose-3-sulfate (sulfatide), requiring preparation of lysosulfatide (sulfogalactosyl-sphingosine) by alkaline hydrolysis of sulfatide and reacylation of the sphingosine amino group with a [1-14C]stearoyl chloride. We found that the yield of labeled sulfatide could be considerably increased using stringent chromatographic conditions for the preparation of lysosulfatide and strict anhydrous conditions for the formation of the acylchloride and its coupling to lysosulfatide. Radioscanning was used at different steps to check the purity of the labeled compounds. Radioscanning was also used to determine the formation of cerebroside when measuring cerebroside sulfate sulfatase activity and sulfatide metabolism in intact fibroblasts in controls and patients with metachromatic leukodystrophy. It could demonstrate and measure with accuracy the cerebroside sulfate storage characteristic of the disease.