[1] Univ Marburg, Inst Physiol, D-35037 Marburg, Germany
[2] Univ Giessen, Inst Anat & Cell Biol, Giessen, Germany
[3] Univ London Imperial Coll Sci Technol & Med, Peripheral Neuropathy Unit, London W12 0NN, England
[4] Aston Univ, Sch Life Sci, Birmingham B4 7ET, W Midlands, England