Rat sciatic nerve regeneration through three synthetic neural prostheses was compared with regeneration through nerve allografts. The synthetic prostheses were either nonpermeable nonabsorbable (Silastic), permeable absorbable (polyglactin mesh), or permeable nonabsorbable (polypropylene mesh). Animals were evaluated at 10, 24, and 90 days. Functional analysis of nerve regeneration was performed by noninvasive methods: electromyography and walking tracks. Nerve tissue was examined with routine histologic and immunofluorescent techniques. A compressive neuropathy developed with the use of the Silastic implant. A neutrophilic inflammatory infiltrate was consistently associated with implantation of the polyglactin mesh. A strong connective tissue response was noted around the polypropylene mesh. Early recovery of nerve function was seen with the Silastic implants, however, overall nerve function was best in the nerve allograft and polypropylene mesh groups. Polyglactin implantation increases the local inflammatory response and should not be used for nerve anastomoses. If Silastic entubulation is used, it should be removed between 24 and 90 days.
Sciatic nerve regeneration through implanted silicone tubes was compared to allogenic nerve grafting in 30 adult female Sprague-Dawley rats. Regeneration was assessed at 10, 24, and 90 days post-transection. Axonal regrowth through the implanted neural prostheses was evaluated with electromyography and histologic examination.
Sinusoidal smooth pursuit eye movements were evaluated in 11 normals, five moderately and four severely affected motor neuron disease (MND) patients, using two target amplitudes and a range of frequencies. This enabled us to examine separately the effects of peak target velocity and acceleration on pursuit gain. Moderately affected patients showed an acceleration, but not a velocity saturation; severely impaired patients' performance declined with increased velocity. Smooth pursuit eye movements are thus impaired in MND, but the nature of this pursuit deficit is complex and changes with the progression of the disease.
Eye movements were recorded using infrared oculography in 17 patients with motor neurone disease (MND) and in 17 age-matched controls. Major findings were a marked reduction in pursuit gain for the severely affected patient group as target speed increased from 10 deg/sec to 20 deg/sec and asymmetric pursuit (leftward gain lower than rightward) in these patients. The authors' study illustrates the effect of MND on the central pathways of the nervous system which control eye movements and shows that an association may exist between specific ocular motor defects and severity.
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