A novel treatment for ischemic intracranial hypertension in cats.

There is no accepted efficacious treatment for ischemic cerebral edema. We show in a cat model of focal cerebral ischemia that infarct volume can be reduced (p less than 0.05) by ventriculocisternal perfusion with an oxygenated fluorochemical emulsion (bis-perfluorobutylethylene). An accompanying effect of such ventriculocisternal perfusion is a reduction in intracranial pressure. At 18 hours following the start of the perfusion, there was a significant (p less than 0.05) difference in intracranial pressure between nonperfused controls (mean 11.4 [range 2.3-23.0] torr, n = 6) and cats perfused with an oxygenated nutrient solution not containing fluorochemical (mean 11.3 [range 3.0-29.0] torr, n = 8) or animals perfused with the oxygenated fluorochemical emulsion (mean 2.21 [range 0-3.5] torr, n = 7). Perfusion with this oxygenated fluorochemical emulsion warrants further study as a treatment for elevated intracranial pressure.

Tellurium-induced demyelination: an electrophysiological and morphological study.

Tellurium (Te) is a naturally occurring element with many industrial uses. Microinjection of 0.3 micrograms of potassium tellurite [K(2)TeO(3)] into the endoneurial space of rat tibial nerve causes a rapidly progressing focal conduction block as measured by the disappearance of the evoked compound muscle action potential (CMAP) of the intrinsic foot muscles following stimulation proximal to the injection site. Conduction block was fully established within 6 hours and persisted for approximately 7 days, followed by the appearance of low amplitude, long latency, temporally dispersed potentials. The proximal CMAPs increased in amplitude and decreased in latency and temporal dispersion until normalization by 28 days after injection. The distal CMAP showed a minimal decline in amplitude. Morphological observations showed splitting of myelin, especially in the paranodal regions, followed by accumulation of myelin debris in Schwann cells and macrophages. Although the exact mechanism remains unknown, this in vivo model provides a unique opportunity to study the electrophysiological and morphological correlates of an acutely evolving demyelinative process.

X-linked motor-sensory neuropathy type-II with deafness and mental retardation: a new disorder.

We report on a family with an apparently X-linked neuromuscular disease. Electrophysiologic tests and electron microscopic studies are consistent with the diagnosis of hereditary motor sensory neuropathy type II (HMSN-II), one form of Charcot-Marie-Tooth disease. The manner of inheritance, the observation that males are severely affected from infancy, and the frequent association of deafness and/or mental retardation with the neuromuscular disorder are not usual for HMSN-II and suggest that this family may have a previously undescribed genetic disorder. The peripheral neuropathy did not appear to be linked to the Xg blood group. Minor abnormalities of sensory nerve conduction, electromyography, and hearing were separately identified in female relatives in this family, but were not consistent enough to be useful in the identification of carriers for this gene.

Myokymia and impaired muscular relaxation with continuous motor unit activity.

We have studied two cases of the syndrome of myokymia and impaired muscular relaxation with continuous motor unit activity. Both patients complained of muscle twitching, weakness, stiffness, and hyperhydrosis during their illness. Myokymia was present over the entire body in both. On repetitive testing of muscle strength each patient showed initial fatigue followed by increasing strength as he continued his efforts. Both patinets improved on phenytoin therapy at high blood levels. Nerve conduction velocities were decreased. Electromyograms showed continuous electrical activity at rest which persisted during sleep and spinal anaesthesia but was diminished by curare. Intravital staining with methylene blue in one case demonstrated sprouting and beading of motor nerve terminals with multiple innervation of muscle fibres. The neurophysiological and pathological findings in these two cases indicate an abnormality of peripheral nerve in this disorder.