Comparative study of intraneuronal polyglucosan bodies in brains from patients with Lafora disease and aged dogs.

We compared intraneuronal polyglucosan body (PGB) in brains from two patients diagnosed as having Lafora disease and from 18 aged dogs (age range: 10 to 22 years, various breeds). PGBs appeared as various-sized spheroids intensely stained with periodic acid-Schiff (PAS) in both humans and aged dogs. Immunohistochemistry with a monoclonal antibody raised against human polyglucosan showed positive staining of the PGBs. Ultrastructurally, PGBs in both humans and aged dogs were composed of fibril-like structures 4 to 20 nm wide. Electron-dense material formed the central cores of the fibrils, but was also scattered in their peripheral areas. The fibril-like structures were intensely stained upon application of the Thiéry procedure. Immunoelectron microscopy showed that the fibril-like structures were specifically labeled with gold particles. The histological, immunohistochemical and ultrastructural features of the PGBs in humans and aged dogs were quite similar.