Stroke; a journal of cerebral circulation
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The neuroprotective role of mild therapeutic hypothermia was established in animal models of cerebral ischemia. Still, several issues, including optimal target temperature, remain unclear. The optimal depth of hypothermia in a rat model of focal cerebral ischemia was investigated. ⋯ Our results suggest that the optimal depth of therapeutic hypothermia in temporary middle cerebral artery occlusion is 34 degrees C.
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Brain ischemia stimulates neurogenesis. However, newborn neurons show a progressive decrease in number over time. Under normal conditions, the cAMP-cAMP responsive element binding protein (CREB) pathway regulates the survival of newborn neurons. Constitutive activation of CREB after brain ischemia also stimulates hippocampal neurogenesis. Thus, activation of cAMP-CREB signaling may provide a promising strategy for enhancing the survival of newborn neurons. We examined whether treatment of mice with the phosphodiesterase-4 inhibitor rolipram enhances hippocampal neurogenesis after ischemia. ⋯ CREB phosphorylation regulates the survival of newborn neurons after ischemia. Chronic pharmacological activation of cAMP-CREB signaling may be therapeutically useful for the enhancement of neurogenesis after ischemia.
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We updated our previous review from 1996 on the risk of rupture of unruptured intracranial aneurysms, aiming to include the newly published articles. ⋯ Age, gender, population, size, site, and type of aneurysm should be considered in the decision whether to treat an unruptured aneurysm. Pooled multivariable analyses of individual data are needed to identify independent risk factors and to provide more reliable risk estimates for individual patients.
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Multicenter Study Comparative Study
Factors influencing the detection of early CT signs of cerebral ischemia: an internet-based, international multiobserver study.
Early CT signs of cerebral ischemia are subtle. Little is known of which factors influence the detection of infarct signs. We compared neuroradiologists' scan readings with those of other specialists involved in the care of stroke patients. ⋯ Non-neuroradiologists should realize that they are unlikely to over-call signs, that old infarcts may distract them from seeing early ischemic signs, and read stroke CT scans more slowly, as these factors may help them perform more like neuroradiologists.
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Clinical Trial
Autonomic ganglionic blockade does not prevent reduction in cerebral blood flow velocity during orthostasis in humans.
The underlying mechanisms for reductions in cerebral blood flow (CBF) during orthostasis are not completely understood. This study tested the hypothesis that sympathetic activation causes cerebral vasoconstriction leading to reductions in CBF during lower body negative pressure (LBNP). ⋯ These data, contrary to our hypothesis, demonstrate that sympathetic vasoconstriction is not the primary mechanism underlying reductions in CBF during moderate LBNP. We speculate that diminished pulse arterial pressure or pulsatile blood flow may reduce cerebral vessel wall shear stress and contribute to reductions in CBF during orthostasis through flow mediated regulatory mechanisms.