Correlation Between Neuronal Apoptosis and Expression of Inducible Nitric Oxide Synthase after Transient Focal Cerebral Ischemia

BACKGROUND: Neuronal death in acute-phase cerebral ischemic injury is caused by necrosis. However, neuronal injury after reperfusion can be associated with apoptosis. METHODS: We used Sprague-Dawley rats whose brains were reperfused after middle cerebral artery occlusion for either 30 min or 2 h. We examined a relationship between apoptosis and the expression of inducible nitric oxide synthase (iNOS) in the brain tissue from 3 h to 14 days after reperfusion in both groups. RESULTS: TUNEL and iNOS positivity were closely related in both groups. The 2-h ischemia group exhibited increases in the amount of TUNEL and iNOS-positive cells for up to 3 days after reperfusion, at which the TUNEL and iNOS-positive cells decreased. The 30-min ischemia group exhibited peak positivity 24 h after reperfusion, followed by a similar decrease. iNOS mRNA expression peaked 3 h after reperfusion in the 30-min ischemia group, at which time it decreased. In the 2-h ischemia group, iNOS mRNA increased 3 h after reperfusion, peaked 24 h after reperfusion, and then decreased. CONCLUSION: These results indicated the occurrence of delayed apoptosis in transient cerebral ischemia. Increased expression of iNOS is closely associated with this apoptosis, and oxygen free radical-producing materials, such as nitric oxide, may play an important role in the induction of this apoptosis.

Intracranial Fibro-Osseous Lesion: A case report and literature review

Intracranial fibro-osseous lesion, also reported as calcifying pseudoneoplasm of the neural axis, is an uncommon lesion of the central nervous system. Since the discovery of this entity by Rhodes and Davis in 1978, there have been a total of 21 cases reported in the literature. We encountered one such case in a 28 year old male, who presented with left hemiparesis for 1 year. By the MR images, a 1.5 cm sized round mass was found at right parietal lobe near motor cortex. The mass lesion enhanced well, homogenously and revealed clear, slightly irregular margin. Excisional biopsy of the mass was performed. Microscopically the lesion was composed of calcified fibrous tissue with an amorphous gray-blue, coarsely fibrillar to chondromyxoid nodular areas. Sparse spindle cells, immunohistochemically negative for GFAP, vimentin and S-100, were scattered within the amorphous material. Palisading spindle or polygonal cells were present at the more cellular periphery of the lesion, which were vimentin positive but S-100 negative. There was no evidence of the pilocytic astrocytes, Rosenthal fibers, or GFAP positive hypertrophic astrocytes. Intracranial fibro-osseous lesions are apparently slow-growing with generally excellent prognosis after wide excision. The etiology remains unclear, but most investigators favor a reactive rather than neoplastic process.