Central nervous system grafting: animal and clinical results

In the 2 years since this topic was reviewed, there have been dramatic changes in our understanding of the basic science of central nervous system transplantation, as well as further realization of the crude state in which we find the clinical application of this technology. Early concepts of simple diffusion and neuronal replacement have been altered as we understand more the rule of neurotrophic factors and the response of the host to the transplantation process. Clinical studies are becoming increasingly sophisticated as we realize that the initial observations were frequently flawed and quantitative evaluations are increasingly important in determining the effectiveness of the procedure. There is, nevertheless, still a great deal of excitement in the field as new technologies are being developed and utilized in the clinical sphere.