The isolation and transplantation of the brain. An historical perspective emphasizing the surgical solutions to the design of these classical models.

Following an historical review of earlier attempts to develop separated head and brain preparations and their contributions to modern-day understanding of the neurophysiology and neurochemistry of the central nervous system, the experiments that eventually led to the first successful total isolation of the mammalian brain are presented. The operative strategies emphasizing the anatomical and physiological problems requiring solution that resulted in vascular and neurogenic separation from the parent body and cephalon are described. The innovative engineering concepts that were utilized in the design of miniaturized equipment to maintain the isolated brain in a living state under conditions of cross circulation, extracorporeal artificial perfusion and transplantation are elaborated. Investigations employing isolated brain and cephalic preparation documenting tissue substrate requirements, metabolic and rheological conditions prevailing at various low temperatures and the immunologically privileged state of the separated organ are briefly presented. The unique opportunities these isolated brain models offer for study are emphasized as well as the complexity of their surgical preparation, which, to date, has limited their universal applications.

The history, theory, and present status of brain transplantation.

Many questions remain unanswered concerning fetal tissue transplantation: Which conditions result in maximal graft survival and function? Which patients are best suited for transplantation therapy? Why do some patients improve more than others? Is immunosuppression necessary when transplanting fetal tissues? Even though the science of neural transplantation is still in its infancy, the clinical use of CNS transplantation has been achieved on a worldwide scale. The many unanswered questions demand continued laboratory investigations and development of more clinically applicable animal models. Ongoing clinical trials will provide advancement of technique and generate more questions. The future is promising for CNS transplantation. As experience and knowledge accumulate, treatment of a greater variety of CNS diseases, including degenerative, traumatic, vascular, and developmental disorders, may find therapeutic options in the realms of brain transplantation. Key factors in transplantation which must be defined relate to donor tissue, transplant technique, and recipient status. Improvements in surgical techniques will advance the field, but the key issue remains how to increase cell survival and axonal extensions within the host brain.

[Importance of the brain in body-soul discussion from the history of medicine perspective]. / Der Stellenwert des Gehirns in der Leib-Seele-Diskussion aus medizinisch-historischer Perspektive.

Since the earliest time medicine has considered our intellectual-psychic abilities in relationship to organs and substrata. Originally blood and its presumptive production resp. depot organs liver and heart acted as soul carriers. Gradually the brain obtained superiority in the body-soul-discussion and during the course of development nearly any structure of the brain was taken into consideration as seat of the soul and the sensorium commune. In the meantime the unity of body and soul never has been controversial among the former medical authors. Since the central nervous system took place of the blood vascular system already at an early time it follows that the brain equally in past and present passed for the material form of our intellectual-psychic abilities. It is true, today we renounce to speak in the body-soul-discussion of single structures of the brain--this has been done intensively and extensively for us by the searchers in former times--, but we still follow the old localisation concept perceiving in the brain and its estimated hundred milliards of nerve cells the unimaginable complex organ that offers the substratum for our intellectual-psychic abilities. Much is not yet realized. But: The genetic material was up to the present a "black box". Today light is fallen in. The efforts concerning this light incidence into the "black box" of the brain must be continued in favour of a successful restorative neurotransplantation.

Stereotactic neural transplantation.

In this keynote address, the author presents state-of-the-art information on the current status of the transplantation of fetal tissue for the treatment of movement disorders. Drawing on the experience in his own studies and elaborating upon the work reported by others, he outlines specific techniques and protocols and summarizes early findings.

Fetal brain tissue grafting as therapy for brain dysfunctions: Unanswered questions, unknown factors, and practical concerns.

Grafting of embryonic neural tissue into the brains of adult patients is being given serious consideration as therapy for a variety of degenerative and traumatic disorders. It has been argued that neural transplantation can promote functional recovery by replacement of damaged nerve cells, the reestablishment of specific nerve pathways lost as a result of injury, the release of specific neurotransmitters, or the production of factors that promote neuronal growth. This review evaluates the use of transplants to promote recovery from brain injury and highlights the kinds of questions and problems that clinicians need to consider before recommending this form of therapy to patients.

Neural transplantation: an historical perspective.

Literature on transplantation of neural and nonneural tissues into the brains of host animals is reviewed in the perspective of various issues. The two dominant issues determining this research were elucidation of embryological processes underlying the development of the nervous system and regeneration in the host brain. A comprehensive review of studies on regeneration in the central nervous system (CNS), using this technique of transplantation, indicates that regeneration of axonal fibers is small in magnitude and extent, and that it is more directly related to the trauma caused to the brain than to any other variable. This literature review attempts to provide a perspective to the contemporary research on neural transplantation and on regeneration in the CNS.