Dr Ignacio Madrazo examining a man suffering from Parkinson's disease, at La Raza hospital, Mexico. In september 1987, Madrazo collaborated with a team of Mexican surgeons to transplant brain tissue from an aborted human foetus into the brain of a person suffering from Parkinson's disease. The Mexicans have subsequently claimed an improvement in the symptoms of the disease. Victims of Parkinson's disease have great difficulty in controlling their movement, due to a failure in the production of dopamine, a chemical required by one of the brain's motor control centres. Grafting of dopamine-containing foetal cells is intended to restore the deficiency.