I called Dr. Gash at the University of Ky. last month concerning his research with GDNF (glial-cell-line-derived neurotrophic factor). His office referred me to AMGEN Inc. in California where the substance was originally discovered. I spoke to a clinician there about whether a pallidotomy would jeopardize anyfuture use of growth factor on a post-pallidotomy patient. Her response was that their research to date has not included the use of this growth factor on MPTT treated primates that have had a pallidotomy. So, we have learned nothing about whether or not a pallidotomy will risk any future use of neuro-growth factors. This has been a concern to me since I am trying to make the decision whether or not to have the operation. Any comments? Claude Dungan ([log in to unmask])