Restorative Neurology and Neuroscience - Volume 8, issue 3

Authors: Zeng, Li | Worseg, Artur | Albrecht, Gerhard | Öhlinger, Wolfgang | Redl, Heinz | Grisold, Wolfgang | Zatloukal, Kurt | Schlag, Günther

Article Type: Research Article

Abstract: Fibrin matrix (FM) is a biological substance involved in the comprehensive wound healing process, and has been used in local applications as a carrier of nerve growth factor (NGF) to achieve an effective local neurotrophic concentration by slow release of the factor. In the present experiment, an exogenous fibrin matrix enriched with laminin (LM) and tubulized by a silicone conduit was used to improve the bridging effect of a peripheral nerve defect in a rat model. A 10 mm nerve defect was bridged with a 14 mm silicone conduit which was prefilled either with 25 μl fibrin matrix enriched without …or with laminin (0.1 μg/ml), serving as groups FM and LM-FM, or with the same amount of saline solution for control (CTR group) (n = 10). After 12 weeks, the nerve conduction velocity and the distal latency were calculated from the electromyographic recordings. In addition, morphological semi-quantitative evaluations in longitudinal and transversal sections were carried out by immuno-histochemical staining with a monoclonal antibody against neurofilament. An improvement in nerve conduction velocity and distal latency, and a better orientation of the regenerated nerve fibers in the gap area were achieved in the LM-FM group than in the CTR and FM groups. These results indicate that the bridging of peripheral nerve defect in a rat model may be improved by the use of exogenous fibrin matrix enriched with laminin (as a filling material) in a silicone conduit. Show more

Keywords: Fibrin matrix, Laminin, Silicone chamber, Nerve regeneration, Rat

DOI: 10.3233/RNN-1995-8301

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 107-111, 1995

Authors: Kasten, Erich | Sabel, Bernhard A.

Article Type: Research Article

Abstract: Brain damage is often accompanied by homonymous hemianopia, but few therapeutic approaches exist for visual field deficits. In this open pilot study we describe a computerized training program which may possibly reduce the size of the ‘blind’ visual field in patients with homonymous visual field deficits. Various stimuli to test light perception and discrimination of colors and shapes were presented on a monitor which permitted the examination or training of the central section of the visual field up to about 25° vertical and 40° horizontal eccentricity. Eleven patients trained at home for 1 h each day for a total of …80–300 h. Their results were compared with those of three patients who opted not to participate in the training procedure or those with very little therapy. These latter subjects had a slight decrease in the visual field size after about 1 year. In contrast, the treatment group displayed a reliable enlargement of visual field size. This was revealed by a significant improvement in the detection of small light stimuli, an increase in the ability to discriminate colors and a minor, but notable, improvement of shape discrimination in the blind areas of the visual field. Additional training of shape recognition led to further improvement of shape discriminations, even when the patients trained with very different kinds of shapes, e.g. lines or letters. Outcome depended on age of the patients and the size of the lesion, but it was independent of on-set of treatment and cause of the lesion. Only two of the 11 patients with treatment showed no significant improvement. This study suggests that regular home training of the ‘blind’ visual field with computer-controlled stimuli may lead to improvement in vision. However, because of the following methodological limitations results are only preliminary: (1) the trial did not contain a true placebo group, (2) the patients were not assigned randomly to a control or treatment condition, (3) the lack of defined inclusion criteria considerably increased the variance in neuropsychological performance, (4) because the experimental design was not double blind, experimenter bias cannot be ruled out, and (5) the conditions of the home training could not be standardized. The results warrant a larger randomized, double-blind controlled trial. Show more

Keywords: Hemianopia, Visual system, Rehabilitation, Brain damage, Recovery of function, Neuroplasticity, Neuropsychology

DOI: 10.3233/RNN-1995-8302

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 113-127, 1995

Authors: Uceda, Gracia | Colombo, Jorge A. | Michelena, Pedro | López, Manuela G. | García, Antonio G.

Article Type: Research Article

Abstract: Adult bovine chromaffin cells are generally resistant to plastic changes when exposed to various culture media. Here, we demonstrate that adrenergic-enriched bovine chromaffin cell populations show significant process extension when co-cultured with fetal rat brain glial fibrillary acid protein (GFAP)+, fibronectin astroglia. Basal medium was ineffective in promoting such growth in chromaffin cells. Initial process formation could be observed about 24 h after seeding, while well developed processes were seen after 3-4 days. Intimate contacts of cytoplasmic extensions with adrenergic chromaffin cells, or with astroglial cells, were frequently observed. Both co-culture with glial cells or exposure to glia-conditioned medium led …to a significant increase in noradrenaline and adrenaline, but not in dopamine content. Since bovine chromaffin cells are widely used as models to study fundamental mechanisms of neurosecretion and phenotype transformation, their co-culture with astroglia may provide a useful strategy to study such phenomena. Show more

Keywords: Chromaffin cells, Glia, Cell plasticity, Catecholamines, Striatum, Astroglia, Neuritogenesis

DOI: 10.3233/RNN-1995-8303

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 129-136, 1995

Authors: Kelly, Melanie-E.M. | Lukowiak, Ken | Bisby, Mark A.

Article Type: Research Article

Abstract: In frogs maintained at 15°C, there is a partial failure of the cell body reaction (CBR) to axotomy. We investigated, in the sympathetic B-cells of the bullfrog, the effects of axotomy at 15°C on the changes in electrophysiological properties which we found previously to follow axotomy at 21°C. While the increase in action potential (AP) duration was delayed by about 14 days, it increased by the normal amount. In contrast, the reduction in after-hyperpolarization (AHP) duration was both delayed and attenuated. These results show that there is a differential expression of these two components of the CBR, with changes in …AHP duration more sensitive to lowered temperature. In attempts to determine if the effect of reduced temperature was on the signalling of axotomy or on the cell body response to the signal, we performed experiments where the 15°C frogs were maintained at 21°C for 7 days, immediately after axotomy, or after various delays. These results suggest that at 15°C, there is an increased delay in signalling that the injury has occurred, but we were not able to show conclusively that maintained expression of the CBR requires an ambient temperature of 21°C. This study emphasizes that the CBR to axotomy is not a unitary response to a single signal, but can be dissected, by lowered ambient temperature, into differentially regulated components. Show more

Keywords: Axotomy, Electrophysiological changes, Sympathetic neurons, Ambient temperature

DOI: 10.3233/RNN-1995-8304

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 137-143, 1995

Authors: Kunert, Hanns J. | Irle, Eva

Article Type: Research Article

Abstract: Cognition and behavior of a 46-year-old woman with a bilateral paramedian thalamic infarction is discussed with regard to dysfunctions of executive behaviors associated with frontal lobe function. The patient displayed marked disturbances in traditional neuropsychological tests measuring frontal lobe functions, as well as in attentional and mnemonic tasks depending on strategic behavior or on response flexibility, response shifting, or response inhibition. Behaviorally, the patient showed considerable apathy, confusion and perseverative tendencies in the acute state, and a diminished psychic self-activation in the chronic state. In spite of long-lasting rehabilitation efforts, the patients' neurobehavioral deficits remained and became obvious in situations …with high cognitive demands. Show more

Keywords: Thalamus, Frontal lobe, Memory, Attention, Higher cognitive functions, Functional restitution

DOI: 10.3233/RNN-1995-8305

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 145-153, 1995

Article Type: Research Article

DOI: 10.3233/RNN-1995-8306

Citation: Restorative Neurology and Neuroscience, vol. 8, no. 3, pp. 155-162, 1995