Ultrastructure of Neurofibrillary Tangles in Steele-Richardson-Olszewski Syndrome

Abstract

The fine structure of neurofibrillary tangles found in the subthalamic bodies and substantia nigra of postmortem brain in one case of Steele-Richardson-Olszewski syndrome was studied with the electron microscope. Most neurons had globose tangles, but flame-shaped tangles and strongly argentophilic fibrillary inclusions resembling Pick bodies were also present. Straight filaments of an average diameter of 150 Angstroms formed the neurofibrillary tangles in neuronal perykaria. These filaments were very stable to postmortem changes and to formaldehyde fixation. There was a difference in caliber and electron density when compared with axonal neurofilaments in the same material. The implications and possible significance of this finding are discussed.