NOGO-A induction and localization during chick brain development indicate a role disparate from neurite outgrowth inhibition

BACKGROUND: Nogo-A, a myelin-associated protein, inhibits neurite outgrowth and abates regeneration in the adult vertebrate central nervous system (CNS) and may play a role in maintaining neural pathways once established. However, the presence of Nogo-A during early CNS development is counterintuitive and hints at an additional role for Nogo-A beyond neurite inhibition. RESULTS: We isolated chicken NOGO-A and determined its sequence. A multiple alignment of the amino acid sequence across divergent species, identified five previously undescribed, Nogo-A specific conserved regions that may be relevant for development. NOGO gene transcripts (NOGO-A, NOGO-B and NOGO-C) were differentially expressed in the CNS during development and a second NOGO-A splice variant was identified. We further localized NOGO-A expression during key phases of CNS development by in situ hybridization. CNS-associated NOGO-A was induced coincident with neural plate formation and up-regulated by FGF in the transformation of non-neural ectoderm into neural precursors. NOGO-A expression was diffuse in the neuroectoderm during the early proliferative phase of development, and migration, but localized to large projection neurons of the optic tectum and tectal-associated nuclei during architectural differentiation, lamination and network establishment. CONCLUSION: These data suggest Nogo-A plays a functional role in the determination of neural identity and/or differentiation and also appears to play a later role in the networking of large projection neurons during neurite formation and synaptogenesis. These data indicate that Nogo-A is a multifunctional protein with additional roles during CNS development that are disparate from its later role of neurite outgrowth inhibition in the adult CNS

Intra-operative real time intracranial subarachnoid haemorrhage during glial tumour resection: A case report

Glial tumours associated with subarachnoid haemorrhage are very rare. A 64-year-old woman admitted with a history of 3 weeks seizures and a left sided hemiparesis and dysphasia. The magnetic resonance disclosed heterogeneously enhancing a right temporal mass. During surgery, suddenly an abrupt and extensive swelling had occurred both in tumour and the brain tissue. The surgery was completed with a gross total tumour resection together with a partial temporal lobectomy. Postoperative computerized tomography demonstrated a massive subarachnoid hemorrhage (SAH). A cerebral Magnetic Resonance (MR) angiography showed neither an aneurysm nor arteriovenous malformation. Coincidence of an intracerebral tumour and subarachnoid haemorrhage would be devastating

Glioblastoma Following Radiosurgery for Meningioma

We report a patient who underwent gamma knife radiosurgery to treat recurrent meningioma after microsurgery and thereafter developed secondary malignancy adjacent to the original tumor. A 47-year-old woman had underwent resection of the olfactory groove meningioma. Then radiosurgery was done three times over 4 year period for the recurrent tumor. After 58 months from the initial radiosurgery, she presented with headache and progressive mental dullness. Huge tumor in bifrontal location was revealed in MRI. Subsequent operation and pathological examination confirmed diagnosis of glioblastoma. This case fits the criteria of radiation-induced tumor and the clinical implication of the issue is discussed

A Case of Hypoglycemic Brain Injuries with Cortical Laminar Necrosis

We report a case of 68-yr-old male who died from brain injuries following an episode of prolonged hypoglycemia. While exploring controversies surrounding magnetic resonance imaging (MRI) findings indicating the bad prognosis in patients with hypoglycemia-induced brain injuries, we here discuss interesting diffusion-MRI of hypoglycemic brain injuries and their prognostic importance focusing on laminar necrosis of the cerebral cortex

Radio-induced low-grade glioma: report of two cases and review of the literature

With the increasing number of cancer survivors, we can observe a population that will present a higher risk of developing secondary long-term toxicities related to adjuvant chemo and radiotherapy regimens. Among these, children surviving from acute lymphoblastic leukemia (ALL) that were treated with prophylactic cranial irradiation represent a group of patients at a high risk of developing secondary brain tumors. Radiation-induced intracranial tumors have been documented since 1950, and today, more than one-hundred cases have been described. We report our experience with two young patients who were hospitalized for low grade gliomas and had a positive anamnesis for ALL and consequent radiotherapy