Restorative Neurology and Neuroscience - Volume 3, issue 3

Authors: Freed, William J.

Article Type: Research Article

Abstract: During the decade since the first reports of functional effects of substantia nigra (SN) transplantation in animal models of Parkinson's disease, the procedure has progressed to human clinical trials. There is evidence that SN grafts can produce some alleviation of the manifestations of SN lesions in animal models, and by several measures these grafts appear to function in a manner similar to the normal SN. There do, however, appear to be limitations on the efficacy of SN allografts in rodent models, that may be related to an inability of fetal SN transplants to fully integrate into the host brain structure. …No method of overcoming this limitation has yet been found. Studies of transplantation of human fetal SN to immunosuppressed rat hosts suggest that human donor tissue exerts proportionately greater effects than rat tissue, and is similarly effective when transplanted as solid tissue fragments or as dissociated cells. Only recently, a few controlled studies have obtained evidence for positive effects of SN grafts in primate models of Parkinson's disease. In the few clinical studies reported thus far, there are indications that some clinical improvements can be produced by SN grafts, although there is little or no evidence that the clinical changes found so far are larger than the changes that have been seen after adrenal medulla grafts. The possibility of a role of striatal injury in the clinical changes has not been resolved. It is noteworthy that nearly all of the studies of SN transplantation in rodents, primates, and humans have employed methodologies similar to those developed in the course of the first few reports on SN transplantation, and that the effects obtained by these methods are limited, even in rats. The possibility is raised that fundamental advances in SN transplantation techniques may be important for the development of a more efficacious clinical procedure. Show more

Keywords: Substantia nigra, Dopamine, Parkinson's disease, Transplantation, Brain graft

DOI: 10.3233/RNN-1991-3301

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 3, pp. 109-134, 1991

Authors: Plumet, Jocelyne | Cadusseau, Josette | Roger, Michel

Article Type: Research Article

Abstract: Limb preference and dexterity of right and left forelimbs were studied in a food reaching task in normal rats (control group), in rats that sustained a neonatal lesion of the left frontal cortex (lesion group) and in animals that received a transplant obtained from the frontal cortex of 16-day-old embryos immediately after the lesion (graft group). In addition, an anatomical study of host–transplant interconnections was performed in several transplanted animals. The results indicate that the lesion slightly increased the preference for the limb ipsilateral to the lesion and transplantation of fetal cortical tissue did not restore the preference for the …contralateral limb. Furthermore, lesion of the motor cortex induced a deficit in the dexterity of limb use in the food-reaching task. This motor deficit was more pronounced when the limb contralateral to the lesion was used. Transplantation of embryonic cortical tissue led to a reduction of the motor deficit. Compared to the lesion group, the graft group had a higher success rate and a lower percentage of motor abnormalities, whichever forelimb was used, ipsi- or contralateral to the transplant. Nevertheless, larger improvement was noted with contralateral forelimb usage. Functional recovery was not complete since the control group still performed significantly better than the graft group, although almost complete sparing in skilled reaching was noted when the limb ipsilateral to the transplant was used. Analysis of host–transplant interconnections indicates that the transplants sent fibers to the host spinal cord, caudate-putamen, thalamus and homotopic contralateral cortex and received projections from the host thalamus and contralateral cortex. It is therefore suggested that neonatal transplantation of fetal cortical tissue promotes functional recovery from damage to the motor cortex occurring at birth. Show more

Keywords: Neonatal cortical lesion, Transplantation, Motor cortex, Functional recovery, Limb preference, Skilled forelimb use, Rat

DOI: 10.3233/RNN-1991-3302

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 3, pp. 135-147, 1991

Authors: de Jong, Andrew | Wang-Bennett, Lolin T. | Liebl, Daniel J. | Coker, Newton J.

Article Type: Research Article

Abstract: In order to compare the extent of axonal regeneration in two surgical nerve repair procedures, we measured the levels of the neurofilament (NF) proteins in the regenerating facial nerve of adult New Zealand rabbits. The animals were operated on bilaterally, with a chamber model placed on one side and a cable graft model inserted on the contralateral side. Normal nerve from unoperated animals or nerve removed during nerve repair surgery served as controls. Using immunoblot techniques and densitometric measurement, we examined specific changes in the individual NF [High (H), Medium (M), and Low (L) molecular weight (MW)] in the regenerating …nerve at 3 and 7 weeks postoperation time. Linearity of the densitometric system was established by separation of serial dilutions of known NF on the gel, and blotting for immunostaining. The amount of all 3 NF's decreased during the regeneration process compared to normal nerve, but there were differences between the two procedures. The NFH in the distal segment of the chamber repaired nerve at 7 weeks was 60–70% of the preoperative state, which correlated with a previous morphological study of axona) caliber during regeneration. At 3 weeks, NF content was lower in the distal segment of the chamber than in the distal cable graft. By 7 weeks, NF content was similar in proximal and distal segments of both models. Thus, although initial regeneration is slower in the chamber model, the eventual outcome is similar in both chamber and graft. Show more

Keywords: Peripheral nerve regeneration, Regeneration chamber, Cable nerve graft, Cytoskeletal proteins, Facial nerve, Rabbit

DOI: 10.3233/RNN-1991-3303

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 3, pp. 149-156, 1991

Authors: Risling, M. | Carlstedt, T. | Lindå, H. | Cullheim, S.

Article Type: Short Communication

Abstract: Previous studies have shown that replantation of avulsed ventral roots may lead to functional reinnervation of hindleg muscles. Regenerating motor axons may regrow for a considerable distance within the spinal cord before entering the replanted ventral root. In this study we show, in the rat and monkey, that many regenerating axons utilize an alternative pathway along the surface of the spinal cord, i.e. the pia mater. This type of reinnervation takes place entirely in the peripheral nervous system.

Keywords: Spinal nerve root, Avulsion lesion, Regeneration, Pia mater, Axon, Electron microscopy

DOI: 10.3233/RNN-1991-3304

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 3, pp. 157-160, 1991

Article Type: Research Article

DOI: 10.3233/RNN-1991-3305

Citation: Restorative Neurology and Neuroscience, vol. 3, no. 3, pp. 161-166, 1991