[johnt]

Pig cell transplants make a comeback.

A paper in Nature as long ago as 1997 explained how pig cells could be used to treat PD.

http://www.nature.com/nm/web_specials/xeno/review.html

Clinical trials were carried out. Some good results were obtained. (See the Jim Finn recent thread.) But, a double blinded phase 2 trial showed both the control and treated groups improving. This raised the possibility that the placebo effect was paramount.

http://www.pbs.org/wgbh/pages/frontl...four/more.html

Fears of retroviral risks appear to have led to a halt in the procedure. Until now:

"The company behind the experimental diabetes treatment Diabecell is seeking Medsafe approval to transplant pig cells into the brains of Parkinson's patients."

http://www.nzdoctor.co.nz/news/2012/...-patients.aspx

John