I haven't kept up on these studies as well as I should, so don't flame me
if some of my statements are incorrect.
As I remember, the adrenal studies were done primarily in Mexico, and
became a subject of dispute, however, a Swedish group headed by (I think)
Anders Bjorklund has been doing studies using fetal mesencephalic cells
to replace striatal dopamine cells. These studies have met with varying
degrees of success.
There is a couple of very good NOVA videos available. The first is
titled The Case of the Frozen Addict, and follows several cases of drug
abusers who obtained a contaminated batch of synthetic meperidine (I
think), which contained MPTP. The second video shows a couple of these
patients who underwent this procedure.
This looks like a potentially promising therapy, but there are many
problems with it. I have a paper which describes the procedure, and its
shortfalls, but it is late, and the paper is at school. If you are
interested I will dig it out and post it.
Dept. of Pharmacology and Toxicology
University of Utah