There is no reliable (read sensitivity/specificity) marker for Alzheimer's or Parkinson. I follow all of the companies/researchers in these segments and know them well.
"Becton, Dickinson and Company (BDX): During the fourth quarter of 2010, Buffett sold out his remaining stake of 1,889,889 shares in the New Jersey-based medical technology company." Source: Seeking Alpha. As they say, "Been there done that".
No way could they be taken out. Very messy, non-compartmentalized and a few other easy to understand reasons. Just chug along with the dividend train.