Teiji Uede

Transplantation of clonal neural precursor cells derived from adult human brain establishes functional peripheral myelin in the rat spinal cord.

We examined the myelin repair potential of transplanted neural precursor cells derived from the adult human brain from tissue removed during surgery. Sections of removed brain indicated that nestin-positive cells were found predominantly in the subventricular zone around the anterior horns of the lateral ventricle and in the dentate nucleus. Neurospheres were established and the nestin-positive cells were clonally expanded in EGF and bFGF. Upon mitogen withdrawal in vitro, the cells differentiated into neuron- and glia-like cells as distinguished by antigenic profiles; the majority of cells in culture showed neuronal and astrocytic properties with a small number of cells showing properties of oligodendrocytes and Schwann cells. When transplanted into the demyelinated adult rat spinal cord immediately upon mitogen withdrawal, the cells elicited extensive remyelination with a peripheral myelin pattern similar to Schwann cell myelination characterized by large cytoplasmic and nuclear regions, a basement membrane, and P0 immunoreactivity. The remyelinated axons conducted impulses at near normal conduction velocities. This suggests that a common neural progenitor cell for CNS and PNS previously described for embryonic neuroepithelial cells may be present in the adult human brain and that transplantation of these cells into the demyelinated spinal cord results in functional remyelination.

Transplantation of Human Olfactory Ensheathing Cells Elicits Remyelination of Demyelinated Rat Spinal Cord

Human olfactory ensheathing cells (OECs) were prepared from adult human olfactory nerves, which were removed during surgery for frontal base tumors, and were transplanted into the demyelinated spinal cord of immunosuppressed adult rats. Extensive remyelination was observed in the lesion site: In situ hybridization using a human DNA probe (COT‐1) indicated a similar number of COT‐1‐positive cells and OEC nuclei within the repaired lesion. The myelination was of a peripheral type with large nuclei and cytoplasmic regions surrounding the axons, characteristic of Schwann cell and OEC remyelination. These results provide evidence that adult human OECs are able to produce Schwann cell‐like myelin sheaths around demyelinated axons in the adult mammalian CNS in vivo. GLIA 30:209–218, 2000.

Transplantation of an Acutely Isolated Bone Marrow Fraction Repairs Demyelinated Adult Rat Spinal Cord Axons

The potential of bone marrow cells to differentiate into myelin‐forming cells and to repair the demyelinated rat spinal cord in vivo was studied using cell transplantation techniques. The dorsal funiculus of the spinal cord was demyelinated by x‐irradiation treatment, followed by microinjection of ethidium bromide. Suspensions of a bone marrow cell fraction acutely isolated from femoral bones in LacZ transgenic mice were prepared by centrifugation on a density gradient (Ficoll‐Paque) to remove erythrocytes, platelets, and debris. The isolated cell fraction contained hematopoietic and nonhematopoietic stem and precursor cells and lymphocytes. The cells were transplanted into the demyelinated dorsal column lesions of immunosuppressed rats. An intense blue β‐galactosidase reaction was observed in the transplantation zone. The genetically labeled bone marrow cells remyelinated the spinal cord with predominately a peripheral pattern of myelination reminiscent of Schwann cell myelination. Transplantation of CD34+ hematopoietic stem cells survived in the lesion, but did not form myelin. These results indicate that bone marrow cells can differentiate in vivo into myelin‐forming cells and repair demyelinated CNS. GLIA 35:26–34, 2001.

Pathogenesis of hyponatremia following subarachnoid hemorrhage due to ruptured cerebral aneurysm

BACKGROUND Hyponatremia following subarachnoid hemorrhage (SAH) occurs due to the inappropriate secretion of antidiuretic hormone (SIADH). However, this condition is also sometimes associated with certain dehydration states. METHODS To clarify the pathogenesis, daily values of urine volume, water balance, and sodium balance (Na Bal) were correlated with plasma levels of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), and plasma renin activity (PRA) in 31 cases of SAH. RESULTS Na Bal was markedly negative on days 2 and 3. Cumulative Na Bal showed continuous negative values until day 10 following SAH. ANP values showed a consistent elevation, while ADH showed only an initial surge. PRA, as the gross indicator of circulatory volume, showed a lack of suppression, indicating no increase in the circulatory volume. CONCLUSION Hyponatremia following SAH therefore appears to be the result of increased natriuresis, due to the inappropriate elevation of ANP rather than SIADH. In this situation, water restriction should not be recommended, since the circulatory volume is decreased.

Results of reoperation for failed microvascular decompression

SummaryAmong 64 patients with hemifacial spasm (HFS) and 60 with trigeminal neuralgia (TN) treated by microvascular decompression (MVD), repeated MVD performed on 3 cases with HFS resulted in the absence of spasm in all cases. In 7 cases with TN, this technique resulted in complete remission in 2, recurrence in 3, and no pain relief in 2 cases. MVD was more effective on HFS than on TN in repeated procedures as well as for initial treatment. The cause of recurrence of HFS was attributed to the inadequate cushion effect of muscle as a prosthesis, while that for TN was suspected to be related more to post-operative fibrotic adhesions formed around the fifth nerve.

Regional ischemia in cerebral venous hypertension due to embolic occlusion of the superior sagittal sinus in the rat

To determine the pathophysiological changes in brain tissue that characterize damage following cerebral venous hypertension, a model of cerebral venous hypertension in the rat was devised. This experimental model has the advantage of simultaneously measuring the regional changes in cerebral blood flow as well as the metabolism. The ischemic area demonstrated by the accumulation of NADH is confined to the cerebral cortex and becomes enlarged in proportion to the increase in venous pressure. This metabolic disturbance appears even in the very early period following cerebral venous hypertension. These pathophysiological features are different from those observed in the case of intracranial hypertension.

Operative approach to mediosuperior cerebellar tumors: occipital interhemispheric transtentorial approach.

BACKGROUND The transtentorial approach is well known as an approach to the pineal region. We have modified this approach for mediosuperior cerebellar tumors. METHODS We describe six cases of tumor excision in this region using an occipital interhemispheric transtentorial approach. RESULTS The lesions were easily accessible and the tumor was totally removed by this modified approach in all cases. Transient visual field disturbance with spontaneous recovery occurred in two patients. The lateral margin of the tumor was accessed easily up to 35 mm from the midline on the operative side and up to 17 mm from the midline on the contralateral side. CONCLUSION This approach proved to be very useful for mediosuperior lesions of the cerebellum, without causing any neural structural damage, and allowed for a wider operative field.

A case of abducens neurinoma mimicking acoustic neurinoma

Neurinoma arising from the abducens nerve independent of neurofibromatosis has been rarely reported in the existing literature. We present a case of abducens neurinoma which was confirmed during a surgical excision. A 31-year-old female had experienced a hearing disturbance for the past 8 months. Abduction of the right eye ball was almost full. Magnetic resonance images showed a tumor having a size of 44 x 33 X 33 mm at the right cerebellopontine angle. Neuro-otological examination revealed the findings specific to acoustic neurinoma. Surgical excision confirmed that the tumor originated from the abducens nerve. The tumor located at the cavernous sinus or cerebellopontine angle might originate from the abducens nerve, though the abduction of eye ball is not in any way impaired.

Vascularized omentum graft for the reconstruction of the skull base after removal of a nasoethmoidal tumor with intracranial extension: case report.

A 16-year-old boy with rhabdomyosarcoma occupying the nasal cavities and the ethmoid sinus with intracranial extension underwent transcranial surgery. The intradural tumor was resected first with the affected dura of the anterior skull base, and the dural defect was repaired with fascia harvested from the sheath of the rectus abdominis muscle. The remaining tumor contiguous to the nasal cavities was completely extirpated. The cranial cavity was then exposed to the opened nasal cavities, where a revascularized omental graft was used to separate these compartments. Lyophilized dura was placed beforehand beneath the omental graft, as a roof to the nasal cavity, and was removed 3 weeks later through the nostril. A bony skull base repair was performed over the omentum using the inner table of the bone flap. Subcutaneous fat from the abdomen was placed on the bone graft for fixation and as an additional seal for the dural defect. Reconstruction of the anterior skull base with a vascularized omental transfer provides an efficient barrier to the nasal cavity. It also serves as an excellent supporting structure for regeneration of the mucosal epithelium of the nasal cavities.

Significant Improvement of Visual Functions after Removal of an Intracranial Giant Optic Nerve Glioma Revealing Exophytic Growth: Case Report

Received, April 6, 2005. Accepted, November 29, 2005. OBJECTIVE AND IMPORTANCE: Intracranial giant optic nerve gliomas, usually presumed as optic chiasmatic gliomas, are much less common. The architectural tumor form of optic nerve glioma without neurofibromatosis type 1 is usually the expansileintraneural pattern. The exophytic optic nerve gliomas without neurofibromatosis type 1 are relatively uncommon. Surgical decompression for intracranial optic gliomas frequently leads to clinical improvement, but obvious improvement of vision is rare. We report a case that demonstrated significant recovery of visual function after removal of the intracranial giant optic nerve glioma, revealing exophytic growth. CLINICAL PRESENTATION: A 13-year-old boy presented with visual impairment in both eyes. Magnetic resonance images (MRI) disclosed a 6 cm diameter mass in the suprasellar area. On heavily T2-reversed MRIs, it was obvious that the intracranial portion of right optic nerve was enlarged, and optic tracts were shifted to the left by the tumor. The relationship of the tumor to the chiasma could not be affirmed on MRIs. INTERVENTION: A right frontotemporal craniotomy for decompression of the optic apparatus was performed. After the majority of the tumor was resected, it became clear that the tumor originated in the right optic nerve. The tumor exophytically grew and dislocated the optic chiasma and optic tracts. Significant improvement of visual functions began from the first week after surgery and continued gradually thereafter. The histological diagnosis was pilocytic astrocytoma. A follow-up MRI taken 4 years after surgery showed no regrowth of the residual tumor. CONCLUSION: Giant exophytic gliomas without neurofibromatosis type 1 may arise from the intracranial portion of an isolated optic nerve. Direct visualization of optic component by heavily T2-reversed MRI could more precisely delineate the relationship of the intracranial optic nerve glioma to the optic apparatus. Surgery may be indicated in giant exophytic intracranial optic nerve gliomas and preoperative postulated optic chiasmatic gliomas. Microsurgical resection can induce postoperative visual improvement without regrowth of the residual tumor.OBJECTIVE AND IMPORTANCE:Intracranial giant optic nerve gliomas, usually presumed as optic chiasmatic gliomas, are much less common. The architectural tumor form of optic nerve glioma without neurofibromatosis type 1 is usually the expansile-intraneural pattern. The exophytic optic nerve gliomas without neurofibromatosis type 1 are relatively uncommon. Surgical decompression for intracranial optic gliomas frequently leads to clinical improvement, but obvious improvement of vision is rare. We report a case that demonstrated significant recovery of visual function after removal of the intracranial giant optic nerve glioma, revealing exophytic growth. CLINICAL PRESENTATION:A 13-year-old boy presented with visual impairment in both eyes. Magnetic resonance images (MRI) disclosed a 6 cm diameter mass in the suprasellar area. On heavily T2-reversed MRIs, it was obvious that the intracranial portion of right optic nerve was enlarged, and optic tracts were shifted to the left by the tumor. The relationship of the tumor to the chiasma could not be affirmed on MRIs. INTERVENTION:A right frontotemporal craniotomy for decompression of the optic apparatus was performed. After the majority of the tumor was resected, it became clear that the tumor originated in the right optic nerve. The tumor exophytically grew and dislocated the optic chiasma and optic tracts. Significant improvement of visual functions began from the first week after surgery and continued gradually thereafter. The histological diagnosis was pilocytic astrocytoma. A follow-up MRI taken 4 years after surgery showed no regrowth of the residual tumor. CONCLUSION:Giant exophytic gliomas without neurofibromatosis type 1 may arise from the intracranial portion of an isolated optic nerve. Direct visualization of optic component by heavily T2-reversed MRI could more precisely delineate the relationship of the intracranial optic nerve glioma to the optic apparatus. Surgery may be indicated in giant exophytic intracranial optic nerve gliomas and preoperative postulated optic chiasmatic gliomas. Microsurgical resection can induce postoperative visual improvement without regrowth of the residual tumor.