Unaltered cytochrome oxidase, glutamate dehydrogenase and glutaminase activities in platelets from patients with sporadic amyotrophic lateral sclerosis--a study of potential pathogenetic mechanisms in neurodegenerative diseases.

Sporadic Amyotrophic Lateral Sclerosis (SALS) is a fatal neurologic disease characterized by degeneration of motor neurons in the spinal cord, brainstem and cortex. While familial cases of ALS exist, the sporadic form accounts for the majority of adult-onset cases. It has been hypothesized that the neurodegenerative mechanisms underlying SALS might arise from glutamate-mediated excitotoxicity and mitochondrial dysfunction. Studies on autopsied SALS spinal cord and brain have reported decreased cytochrome oxidase activity, decreased astrocytic glutamate-transporter protein, and alterations of glutamate levels and glutamate metabolizing enzyme activities. We conjectured that if alterations in glutamate metabolism and cytochrome oxidase activity occur in the SALS central nervous system these alterations may also be manifested in peripheral tissues such as platelets in living SALS patients. In this study we compared the activities of cytochrome oxidase, citrate synthase, glutamate dehydrogenase and glutaminase in platelets from SALS and control subjects. We found that there were no differences in any of the enzyme activities measured between the two groups. Our data argue against generalized ubiquitous biochemical alterations of these enzymes in SALS patients.

Bilateral intracavernous carotid aneurysms mimicking a prolactin-secreting pituitary tumor.

The triad of hyperprolactinemia, ophthalmoplegia, and radiologic abnormalities of the sell turcica suggest a tumor in the area of the pituitary gland. A new association--bilateral intracavernous carotid aneurysms--is presented. Two elderly women had extraocular muscle palsies and elevated serum prolactin levels of 71 and 32 ng/ml (normal: less than 20 ng/ml). In the former, a high-resolution computed tomography scan made after contrast medium injection was incorrectly interpreted as demonstrating a pituitary tumor; cerebral arteriography revealed bilateral aneurysms. In the other patient, a computed tomography scan after contrast medium injection demonstrated the bilateral aneurysms, and these were confirmed by radionuclide angiography.