Restorative Neurology and Neuroscience - Volume 14, issue 4

Authors: Geeraerts, Sarah | Vandenbussche, Erik

Article Type: Research Article

Abstract: The purpose of the present study was to observe recovery of orienting deficits during unilateral and bilateral cooling inactivation of the middle suprasylvian (MS) cortex. Unilateral MS cooling resulted in a contralateral hemineglect (no orienting responses towards stimuli in the contracooled hemifield) that spontaneously recovered within less than 40 min of continued cooling. Moreover, the brain changes responsible for this recovery were partially retained and cumulated over successive cooling days. Bilateral MS …cooling indicated that recovery of neglect can be induced by a restoration of the imbalance between activity levels of structures in both hemispheres and revealed an interaction between spontaneous and induced recovery of neglect. These results show that considerable changes may occur in the brain during cooling for rather short periods. Possible explanations for these changes are discussed. Show more

Keywords: cooling, plasticity, neglect, orienting behavior, perimetry

Citation: Restorative Neurology and Neuroscience, vol. 14, no. 4, pp. 237-250, 1999

Authors: Kitada, Masaaki | Mizoguchi, Akira | Tohyama, Koujiro | Ohtsubo, Akinori | Fujimoto, Etsuko | Chakrabortty, Shushovan | Ide, Chizuka

Article Type: Research Article

Abstract: Axonal and glial reactions to traumatic injury were compared between the caudal and rostral border of the lesion after freeze-injury to the C3 dorsal funiculus by attaching a liquid nitrogen-cooled copper probe to the dorsum of the rat spinal cord. The axonal and glial changes were examined up to 60 days postoperative by light and electron microscopy and immunohistochemistry for neurofilaments. Regenerative axonal changes and the appearance of numerous undifferentiated cells were found at the caudal …border 7 days after cryoinjury. In contrast, such axonal and cellular reactions were scarce at the rostral border. Undifferentiated cells clearly manifested their phenotypes by differentiating into oligodendrocytes or astrocytes 11 days postinjury. The results indicated that glial cell reactions occurred in association with regenerative axonal changes at the proximal stump of the injured nerve fibers, suggesting that regenerating and demyelinated naked axons could be responsible for the appearance of the immature glial cells. Show more

Keywords: spinal cord, cryoinjury, regenerating axons, glial cell reaction

Citation: Restorative Neurology and Neuroscience, vol. 14, no. 4, pp. 251-263, 1999

Authors: Itoh, Soichiro | Samejima, Hirotake | Shinomiya, Kenichi | Awaya, Akira

Article Type: Research Article

Abstract: The effects of pyrimidine heterocyclic compounds (MS-818 and MS-430) on nerve regeneration were evaluated using the cut-and-suture model of the right sciatic nerve of Wistar rats. After surgery, 1 or 5 mg/kg/day of MS-818 or MS-430 was intraperitoneally administered for 21 days. Control rats received the same surgery, but were administered saline instead of a drug. Each week from week 2, evoked muscle action potentials were recorded on the calf muscle to compare the ratio of …latency and amplitude between tbe experimental and non-treated side. The specimens were taken from the tibial nerve for light microscopic observation; and the diameter, density and % axon area of myelinated axons were evaluated. Tbe results of EMG and histology suggest that administration of MS-818 is more effective than that of MS-430 and that administration of 5 mg/kg/day has a higher promoting effect than that of 1 mg/kg/day for sprouting and elongation of the severed nerve. These new neurotrophic pyrimidine compounds may be a group of possible substances effective in facilitating nerve regeneration. Show more

Keywords: pyrimidine heterocyclic compounds, , MS-818, MS-430 , nerve regeneration, peripheral nerve

Citation: Restorative Neurology and Neuroscience, vol. 14, no. 4, pp. 265-273, 1999

Authors: Dubuisson, Annie S. | Lapiere, Charles M. | Nusgens, Betty V.

Article Type: Research Article

Abstract: Our aim is to devise an artificially reconstituted nerve segment made of a three-dimensional collagen gel populated with aligned fibroblasts and Schwann cells. Collagen lattices were prepared by mixing concentrated medium, a type I collagen solution and rat Schwann cells (SC), rat neural fibroblasts (nF) or human dermal fibroblasts (dF) and allowed to polymerize at 37 °C. In these free-floating lattices, nF and dF retracted the gel more than SC. All cells appeared to be elongated …and oriented at random. Rat cells obtained by enzymatic digestion of nerves undergoing wallerian degeneration retracted the gel at a larger extent than cells from intact nerves. Rectangular lattices restrained at each extremity acquired a paraboloid shape upon retraction by neural or dermal F reflecting the mechanical tension developed by these cells on their support. Adult SC alone produced a faint paraboloid even at high cell density while SC associated with nF developed a paraboloid similar to that obtained with nF alone. The mechanical force developed by dermal F and SC in the restrained lattice was measured by strain gauges and found much higher for F than for SC. In restrained lattices, both types of F were elongated and aligned to the long axis of the gel while SC elongated but not necessarily in a parallel fashion. The central portion of a mixed nF-SC collagen restrained lattice produces a flattened cylindric segment made of longitudinally oriented col-lagen fibrils, F and SC, which could represent a promising material for preparation of nerve grafts. An original plastic mould was devised to allow the preparation of cylindrical segments of free or restrained collagen lattices in view of in vitro and in vivo regeneration studies. Show more

Keywords: collagen lattice, Schwann cell, fibroblast, extracellular matrix, mechanical force, artificial nerve graft

Citation: Restorative Neurology and Neuroscience, vol. 14, no. 4, pp. 275-284, 1999

Authors: Dixon, C. Edward | Kraus, Marilyn F. | Kline, Anthony E. | Ma, Xiecheng | Yan, Hong Q. | Griffith, Raymond G. | Wolfson, Brian M. | Marion, Donald W.

Article Type: Research Article

Abstract: Amantadine, a dopamine agonist, is reported to have beneficial effects on the neurobehavioral sequelae of clinical brain injury. However, there are currently no published laboratory reports on its use in the assessment of functional or histopathological outcome following experimental traumatic brain injury (TBI). To this end, we examined the effects of daily amantadine treatment on functional recovery (motor and Morris water maze performance) and hippocampal neuronal survival following controlled cortical impact (CCI) …injury (4 meters/sec, 2.7 mm tissue deformation). Male Sprague-Dawley rats were pretrained on motor performance tasks (beam balance and beam walking) one day prior to injury and tested on post-operative days 15. Additionally, all subjects were trained on the Morris water maze on post-operative days 1418. Beginning one day after CCI injury or sham surgery, animals were injected once daily for 18 days with either amantadine (10 mg/kg, i.p.) or saline. The amantadine treatment regimen was ineffective in promoting motor recovery and increasing survival of hippocampal neurons in both the CA1 and CA3 regions following TBI, but did show improved swim latencies during the five days of water maze testing (Day 14 vs. Day 18, p < 0.01) when compared to saline controls. Mean (± SE) swim latencies on Day 18 were 15.12 ± 2.8, 13.25 ± 4.18, 70.83 ± 11.1, and 38.5 ± 3.55 sec for the sham/saline, sham/amantadine, injured/saline, and injured/amantadine treatment groups, respectively. Thus, while the daily administration of amantadine exhibited a neutral effect on motor behavior, it produced a modest attenuation of water maze performance deficits. This latter finding is consistent with published clinical data suggesting a beneficial effect on functional outcome with amantadine therapy. Show more

Keywords: brain injury, amantadine, dopamine , rat

Citation: Restorative Neurology and Neuroscience, vol. 14, no. 4, pp. 285-294, 1999