Transplantation of cryopreserved adult human Schwann cells enhances axonal conduction in demyelinated spinal cord.

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.

[Characteristic improvement of the function following Schwann cell transplantation for demyelinated spinal cord].

Transplantation of Schwann cells (SCs) induced remyelination of demyelinated rat dorsal column (DC) axons and improved conduction. To investigate the difference between oligodendrocyte (OL) and SC myelination in conductive functions of axons, we compared normal DCs, demyelinated DCs, demyelinated DCs remyelinated by SC transplantation, and normal dorsal roots. All of the axons was originated from dorsal root ganglion neurons. Dorsal roots of adult rats were demyelinated at T11 by X-ray irradiation and ethidium bromide, and transplanted with SCs (3 x 10(4)) of adult rats. Three weeks later, the spinal cord was removed and pinned in a recording chamber and compound action potentials (CAPs) were recorded, to investigate conduction properties (conduction velocity and response after high frequency stimulation). Normal DCs or dorsal roots were recorded in same manner. Following transplantation of SCs, histological examination revealed SC-like patterns of remyelination in demyelinated DCs. SC transplantation improved significantly conduction properties compared to demyelinated axons, but less than normal DC. Moreover, remyelinated axons by SC transplantation showed as low amplitude of CAP as dorsal roots, but lower conduction velocity than dorsal roots. Though anatomical difference and/or time after transplantation influenced the conduction, these result suggested that SC myelination resulted in lower amplitude of CAP than OL, and SC remyelination might be insufficient for conduction velocity.

Synaptic reorganization in the substantia gelatinosa after peripheral nerve neuroma formation: aberrant innervation of lamina II neurons by Abeta afferents.

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.

Intraparenchymal meningioma in an infant--case report.

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 revealed 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 preoperative 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 diagnosis 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.

Afferent projections to the Bötzinger complex from the upper cervical cord and other respiratory related structures in the brainstem in cats: retrograde WGA-HRP tracing.

Following injection of WGA-HRP (30-60 nl, 5%) into the Bötzinger complex (Böt.c), a group of expiratory neurons in the vicinity of the retrofacial nucleus, a number of labeled neurons were observed, predominantly ipsilaterally, in the intermediate zone of the upper cervical cord at the C1 and C2 segments, the retrotrapezoid nucleus (RTN) in the ventrolateral medulla and the parabrachial-Kölliker-Fuse nuclear complex in the rostral pons. In addition, clusters of labeled cells were also observed in and around the solitary tract nucleus, nuclei ambiguus and retroambiguus, and nucleus raphe magnus. Control injections into the magnocellular tegmental field adjacent to the Böt.c resulted in a diffuse distribution of labeled neurons in the reticular formation. These results demonstrate that the Böt.c receives convergent monosynaptic axonal projections from the upper cervical spinal cord, the pontine pneumotaxic area, the RTN and several other respiratory related structures in the medulla.

Magnetic resonance imaging characteristics of choroid plexus papilloma in the fourth ventricle.

The computed tomography (CT) and magnetic resonance (MR) imaging characteristics of two cases of small choroid plexus papilloma within the fourth ventricle are reported. CT showed the tumors as high density areas with postcontrast enhancement. MR imaging showed the tumors as basically isointense areas with marked enhancement by gadolinium-diethylenetriaminepenta-acetic acid. Important MR imaging findings included clear evidence of tumor attachment to the normal choroid plexus, location in the lower part of the fourth ventricle, and separation from the fourth ventricular floor.