Jafar Afshar

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The continuous release of nitric oxide (NO) is required to maintain basal cerebrovascular tone. Oxyhemoglobin, a putative spasmogen, rapidly binds NO, implicating loss of NO in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). If vasospasm is mediated by depletion of NO in the vessel wall, it should be reversible by replacement(More)
To establish if interruption of the intradural draining spinal vein or surgical excision are curative treatments for spinal dural arteriovenous fistulas (AVFs), the medical records and radiographic studies of 19 patients with spinal dural AVFs and progressive myelopathy were reviewed. Spinal arteriograms were obtained before and within 2 weeks after surgery(More)
Despite years of research, delayed cerebral vasospasm remains a serious complication of subarachnoid hemorrhage (SAH). Recently, it has been proposed that endothelin-1 (ET-1) mediates vasospasm. The authors examined this hypothesis in a series of experiments. In a primate model of SAH, serial ET-1 levels were measured in samples from the perivascular space(More)
OBJECT The reduction in the level of nitric oxide (NO) is a purported mechanism of delayed vasospasm after subarachnoid hemorrhage (SAH). Evidence in support of a causative role for NO includes the disappearance of nitric oxide synthase (NOS) from the adventitia of vessels in spasm, the destruction of NO by hemoglobin released from the clot into the(More)
UNLABELLED Hemoglobin released from hemolysed erythrocytes has been postulated to be responsible for delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). However, the evidence is indirect and the mechanisms of action are unclear. Cerebrovascular tone is regulated by a dynamic balance of relaxing and contracting factors. Loss of the(More)
The deep rostral piriform cortex contains a site (area tempestas) in which focal application of picomole amounts of bicuculline, a GABA antagonist, triggers limbic motor seizures which are dependent upon activation of both N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyloxole-4-proprionate subtypes of glutamate receptors. In the present study we(More)
How to resolve query ambiguity and how to avoid redundancies in a search result? The redundancy in returned results(e.g., near duplicates) has a negative effect on retrieval effectiveness(i.e., user satisfaction) and there is less benefit in representing relevant yet redundant results to the user repeatedly. So the ambiguity of query needs to be reflected(More)
Patent has currently been captured strong attention as a key enabler for the knowledge and information centric companies and institutes. The higher the patent capability required, the more important an effective and efficient patent retrieval system needed. The conventional patent retrieval systems, however, have produced unsatisfactory results for the(More)
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