We have investigated the urinary recovery of S-oxide metabolites of the probe aliphatic sulfide (thioether) compound S-carboxymethyl-L-cysteine (SCMC) in Parkinson's (PD), motor neurone (MND) and Alzheimer's (AD) diseases since previous studies in small populations have indicated a defect in S-oxide formation. In this study, 201 controls, 175 PD, 86 MND and 23 AD patients were investigated for their ability to produce urinary S-oxide metabolites of SCMC. The patient populations showed significantly higher number of individuals in the none S-oxide forming phenotype (39.4% PD, 38.3% MND, 56.5% AD compared to 6.9% of the control population). This results in odds risk ratios of 10.5 (PD), 10.04 (MND) and 15.21 (AD) for an individual developing these three diseases if they are unable to produce S-oxide metabolites of SCMC. The ability to form S-oxide metabolites from aliphatic sulfide compounds may be a protection mechanism against environmental/dietary sulfur containing toxins or protoxins. Med Sci Res 27:119-120 (C) 1999 Lippincott Williams & Wilkins.

Platelet MAO-B levels have been investigated in seventeen consecutively diagnosed and previously untreated patients with idiopathic Parkinson's disease using the non-hydroxylated catecholamine, β-phenylethylamine, as substrate. Patients with Parkinson's disease had MAO-B activity levels that were considerably higher than sex and age matched normal controls or patients with Motor neurone disease or Myasthenia gravis.