Concentrations of zinc and iron in the brains of Guamanian patients with amyotrophic lateral sclerosis and parkinsonism-dementia.

Simultaneous measurements of zinc (Zn) and iron (Fe) concentrations were determined using neutron activation analysis in gray and white matter of the frontal and occipital regions obtained from four patients with parkinsonism-dementia (PD), eight with amyotrophic lateral sclerosis (ALS), and four neurologically normal controls from Guam. Zn content in gray matter from the frontal cortex in ALS and PD cases was significantly decreased, compared with that of controls (p < 0.05). No significant differences were found in the Zn content of white matter from the frontal cortex, and/or gray and white matter from the occipital cortex between the groups. The Zn content in gray matter from both frontal and occipital regions was less in ALS and PD patients than in controls. Fe content in gray matter from the frontal cortex of ALS and PD increased significantly compared with that of controls (p < 0.05). Fe content in white matter from the frontal cortex in PD patients was greater than in controls (p < 0.05), with an overall difference: controls < ALS < PD. These data indicate that an increase in Fe in gray and white matter, and a decrease concentration of Zn in gray matter, combined with an excess and deficiency of bioavailable aluminum and calcium, respectively, may be involved in the pathogenic process of these disorders.