X-RAY MICROPROBE ANALYSIS OF CORPORA-AMYLACEA

Since corpora amylacea is concentrated in the high density fraction in the subcellular fractionation of autopsy brain, it is suspected that inorganic materials accumulate in corpora amylacea, Therefore, element al analyses of partially purified corpora amylacea from autopsy brain from a patient with Alzheimer's disease and those from brain of a non- demented patient were performed by the X-ray microprobe method. Promin ent peaks of sodium, phosphorus, sulphur and chloride were observed, a nd mapping analyses confirmed that these elements were actually contai ned within the corpora amylacea. A similar result was obtained using c ryostat sections. Corpora amylacea are characteristically distributed along the margin of blood vessels, beneath the pial border of the hipp ocampus and in the subependymal zones of ventricles of aged brains, na mely in the vicinity of blood and cerebrospinal fluid. From this distr ibution and from the results of the present paper, we suggest that cor pora amylacea play a role in the absorption and accumulation of inorga nic materials which have been extravasated from blood and cerebrospina l fluid (CSF) and taken up by astrocytes. This may reflect alteration of the blood-brain and blood-CSF barriers in the ageing brain.