Mechanical instability of Pick bodies and their isolation in an intact form using urea solution.

Isolation of Pick bodies was attempted from an autopsied brain of a patient with Pick's disease following a modified method for isolation of senile plaques cores and neurofibrillary tangles in the brains of Alzheimer's disease. Pick bodies were mechanically less stable than senile plaque cores and neurofibrillary tangles since Pick bodies were destroyed by vigorous homogenization or treatment with 1% sodium dodecyl sulfate solution. Pick bodies were released out of mother neuronal cells in an intact form by treatment with 8 M urea solution for several hours at room temperature. Finally, fine structure of Pick filaments released from Pick bodies was compared with the filaments of neurofibrillary tangles.