Restorative Neurology and Neuroscience - Volume 2, issue 2

Authors: Luo, Danhua | Chakraborty, Goutam | Ingoglia, Nicholas A.

Article Type: Research Article

Abstract: Following crush injury to rat sciatic nerves, a crude fraction of the 150,000 g supernatant can post-translationally incorporate [3 H]Arg and [3 H]Lys into endogenous proteins in amounts approximately 10 times uninjured control nerves. These increases occur in the proximal nerve stump within 2 h of injury and 2 weeks later in a distal segment of nerve containing the tips of the regenerating axons. In the present experiments, the endogenous nerve proteins modified by Arg or Lys in these nerve segments have been identified using two-dimensional polyacrylamide gel electrophoresis. The fraction used to assay for protein modification, the void volume …of a Sephacryl S-300 column, was found to contain only a few proteins visible by Coomassie blue staining, one of which is likely to be albumin (68 kDa, pI 6.4). While this protein was modified by both Arg and Lys, the majority of label was found in areas not showing Coomassie blue staining. This indicates that of the many potential targets of post-translational arginylation and lysylation, most are proteins of relatively low abundance. A variety of proteins were modified by Arg or Lys alone while others were modified by both Arg and Lys. A high molecular weight protein (175 kDa, pI 9.0) was modified only by Lys and only at 2 h post crush. Of a variety of modified proteins of approximately 17 kDa one (pI 6.3) was modified by both Arg and Lys and at both time points, while another (pI 9.0) was modified at both time points, but only by Lys. The results show that Arg and Lys can be added post-translationally to a large number of low abundance, soluble sciatic nerve proteins, and that some of those proteins are modified only by Arg or Lys while others are modified by both Arg and Lys. Also, the modification of certain proteins appears to be associated specifically with the immediate response of a nerve to injury (e.g. 88 kDa, pI 7.1) while others are associated with the regenerative period (e.g. 56 kDa, pI 7.4). Show more

Keywords: Regeneration, Sciatic nerve, Posttranslational, Arginine, Lysine, Protein

DOI: 10.3233/RNN-1990-2201

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 53-61, 1990

Authors: Thanos, Solon | Vanselow, Jens

Article Type: Research Article

Abstract: The present work elucidates the connectivity of adult retinal ganglion cell axons regenerating through grafted peripheral nerve segments with co-grafted immature brain target cells. The optic nerve of rats was transected intraorbitally and its segment distal to the transection was replaced by a 3 cm length of peroneus communis graft, that is known to permit regeneration of a certain proportion of the severed axonal population. Five weeks after optic nerve transection and peripheral nerve transplantation the regenerating optic tract axons were guided into rat fetal mesencephalic co-grafts (E14–16) placed in superficial cavities prepared in the occipital cortex. The rationale of …the experimental setup was based on the fact that regrowth of retinal axons started at the 6th day after transection, whereas the fastest-growing axons reached the distal end of the transplanted peripheral nerve 4 weeks later growing with a velocity of about 1.33 mm/day. Therefore, grafting the fetal superior colliculus at the time axons arrive distally resulted in ingrowth of several hundreds of retinal axons into this immature, retinoreceptive brain tissue. Retinal axons which penetrated the fetal grafts contacted tectal neurons and GFAP-immunoreactive glia and formed typical retinocollicular axonal arbors as detected by anterograde labeling with RITC from the retina. In addition, sprouting fibers from the adjacent adult cortical neurons penetrated frequently the fetal transplants. By ‘bridging’ lesions with peripheral nerve pieces and providing immature neurons as targets for growing neurites, this transplantation model is suitable for investigations on whether regenerating adult neurites are capable of reforming connections. The co-transplantation technique may serve as a tool for understanding whether interrupted circuitries in the central nervous system can be functionally restored over long distances by the use of peripheral nerve grafts and immature nervous system tissue. Show more

Keywords: Rat visual system, Axonal regeneration, Peripheral nerve grafts, Fetal grafts, Immunohistochemistry, Fluorescent markers

DOI: 10.3233/RNN-1990-2202

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 63-75, 1990

Authors: Detta, Allah | Hitchcock, Edward

Article Type: Research Article

Abstract: Foetal tissue from cortex, striatum, cerebellum and mesencephalon of human foetuses of gestational age 18 weeks have been examined for cell viability pre- and postpassage through needles of varying dimensions. Fully dispersed cells have less viability than cell clumps, but needle lumenar sizes employed in this study do not appear to have any significant influence on viability as measured by the vital staining method. There is a tendency of narrower needles to adversely affect viability of both dispersed and clumped cells; the vulnerability of component cells, i.e. neurones or glia has not been determined.

Keywords: Fetal, Neuron, Viability, Neural transplantation, Vital stain

DOI: 10.3233/RNN-1990-2203

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 77-80, 1990

Authors: Filliatreau, Ghislaine | Hässig, Raymonde | Di Giamberardino, Luigi

Article Type: Research Article

Abstract: We studied the modifications occurring in the parent cytoskeleton carried by SCa (the slower of the two slow axonal transport subcomponents) after peripheral nerve crush. The proteins transported in rat sciatic motor axons were radiolabelled by injecting [35 S]methionine into the ventral horn of the spinal cord, and the nerve was crushed so as to entrap only the proteins transported by SCa along the parent axon. Two weeks after the crush, the regenerating nerve was removed and the distributions of the polymerized and unpolymerized radiolabelled cytoskeletal proteins were compared with those in normal, non-regenerating nerves. We found that in the …parent axons, most of the radioactive neurofilaments were arrested by the crush, but microtubules, soluble tubulin, insoluble and soluble actin were normally transported. Thus, when the resulting cytoskeleton transported by SCa entered the daughter axon, it was enriched in microtubules and actin, and partially depleted of neurofilaments. This cytoskeleton contained larger proportions of soluble tubulin and insoluble actin than the parent cytoskeleton, but retained its coordinated progression and transport velocity, suggesting that after axotomy, the main destiny of the parent cytoskeleton carried by SCa is to become the equivalent cytoskeleton in the daughter axons. Show more

Keywords: Axonal regeneration, Cytoskeleton, Slow axonal transport, Peripheral nerve, Neurofilament, Microtubule, Actin

DOI: 10.3233/RNN-1990-2204

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 81-88, 1990

Authors: Rosen, Joseph M. | Grosser, Morton | Hentz, Vincent R.

Article Type: Research Article

Abstract: Many of the present limitations of peripheral nerve repair might be overcome by performing nerve repairs at the axon level. One approach to nerve repair at this level would be to implant a neuroprosthesis in the form of a microelectronic switchboard which could route the connections of regenerated axons to their correct destinations. This requires a merger of microsurgery and microelectronics. Three steps are needed to achieve this goal. (1) The achievement of in vivo compatibility and electrical contact between axons and a material compatible with microelectronics. (2) The fabrication of a microelectronic neuroprosthesis with electrodes to establish communication with …the axon. (3) The development of signal processing hardware and software to control the mapping of the regenerated axons. This report describes preliminary experiments in regenerating peripheral nerve axons through an electronic-grade silicon chip with laser-drilled holes small enough to capture either one or a few axons per hole. We have observed the viability of such nerves in 4 rats for 6 months to 1 year, and in two primates for more than 3 months. As our experiments show, this technique is not yet as effective as suture repair, but the development of a neuroprosthesis that communicates with peripheral nerve axons could have applications including nerve repair, neuroma, and nerve grafts, as well as interfacing the peripheral nervous system to prostheses of other kinds. Show more

Keywords: Axon processor, Microelectronic axon processor (MAP), Nerve chip, Nerve regeneration, Nerve repair, Neuroelectronics, Neuroprosthesis, Peripheral nerve repair

DOI: 10.3233/RNN-1990-2205

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 89-102, 1990

Article Type: Research Article

DOI: 10.3233/RNN-1990-2206

Citation: Restorative Neurology and Neuroscience, vol. 2, no. 2, pp. 103-107, 1990