Schwann cells derived from human sural nerve may provide a valuable source of tissue for a cell-based therapy in multiple sclerosis. However, it is essential to show that transplanted human Schwann cells can remyelinate axons in adult CNS and improve axonal conduction. Sections of sural nerve were removed from amputated legs of patients with vascular disease or diabetes, and Schwann cells were isolated and cryopreserved. Suspensions of reconstituted cells were transplanted into the X-irradiation/ethidium bromide lesioned dorsal columns of immunosuppressed Wistar rat. After 3-5 weeks of extensive remyelination, a typical Schwann cell pattern was observed in the lesion zone. Many cells in the lesion were immunopositive for an anti-human nuclei monoclonal antibody. The dorsal columns were removed and maintained in an in vitro recording chamber; the conduction properties were studied using field potential and intra-axonal recording techniques. The transplanted dorsal columns displayed improved conduction velocity and frequency-response properties, and action potentials conducted over a greater distance into the lesion, suggesting that conduction block was overcome. These data support the conclusion that transplantation of human Schwann cells results in functional remyelination of a dorsal column lesion.

Intracellular recording and extracellular field potential (FP) recordings were obtained from spinal cord dorsal horn neurons (laminae I-IV) in a rat transverse slice preparation with attached dorsal roots. To study changes in synaptic inputs after neuroma formation, the sciatic nerve was sectioned and ligated 3 weeks before in vitro electrophysiological analysis. Horseradish peroxidase labeling of dorsal root axons indicated that Abeta fibers sprouted into laminae I-II from deeper laminae after sciatic nerve section. FP recordings from dorsal horns of normal spinal cord slices revealed long-latency synaptic responses in lamina II and short-latency responses in lamina III. The latencies of synaptic FPs recorded in lamina II of the dorsal horn after sciatic nerve section were reduced. The majority of monosynaptic EPSPs recorded with intracellular microelectrodes from lamina II neurons in control slices were elicited by high-threshold nerve stimulation, whereas the majority of monosynaptic EPSPs recorded in lamina III were elicited by low-threshold nerve stimulation. After sciatic nerve section, 31 of 57 (54%) EPSPs recorded in lamina II were elicited by low-threshold stimulation. The majority of low-threshold EPSPs in lamina II neurons after axotomy displayed properties similar to low-threshold EPSPs in lamina III of control slices. These results indicate that reoccupation of lamina II synapses by sprouting Abeta fibers normally terminating in lamina III occurs after sciatic nerve neuroma formation. Furthermore, these observations indicate that the lamina II neurons receive inappropriate sensory information from low-threshold mechanoreceptor after sciatic nerve neuroma formation.

A 1-year and 10-month-old girl presented with an intraparenchymal meningioma in the left frontal lobe manifesting as grand-mal seizures. Computed tomography and magnetic resonance images re vealed a round, well-demarcated mass in the left frontal lobe which was homogeneously enhanced . Angiography showed the feeding arteries of the tumor from the middle cerebral artery . The preopera tive diagnosis was an intraaxial tumor. At operation, the lesion was totally embedded in the frontal lobe without any connection to the overlying dura or the ventricular system. Some small feeders from the middle cerebral artery were coagulated and the tumor was totally removed. The histological diag nosis was fibroblastic meningioma.Her postoperative course was uneventful . She was doing well 2 years after surgery. Intraparenchymal meningiomas may be seen more frequently than expected in children. Absence of dural attachment is characteristic of pediatric meningiomas .

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