[1] Ist Ortoped Rizzoli, Lab Neuromuscular Pathol, I-40136 Bologna, Italy
[2] Ist Ortoped Rizzoli, Lab Cellular Biol & Electron Microscopy, I-40136 Bologna, Italy
[3] Genethon, URA 1923, Evry, France
[4] Univ Newcastle Upon Tyne, Sch Med, Dept Neurobiol, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England