Stroke; a journal of cerebral circulation
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While brain tissue lactate increases during cerebral ischemia and is known to be important in the pathogenesis of ischemic brain injury, patterns of extracellular lactate accumulation have been less well characterized, and the influence of brain temperature has not been previously investigated. Mild brain temperature modulations are known to affect the outcome of ischemia dramatically. This study examined changes of extracellular lactate during and after global cerebral ischemia, in which intraischemic brain temperature was held at either 30 degrees C, 37 degrees C, or 39 degrees C. ⋯ These data provide evidence that extracellular lactate accumulation is not a crucial determinant of ischemic brain injury. Our results suggest that the increased lactate release during ischemia and the accelerated clearance of lactate during recirculation might contribute in part to the neuroprotection of intraischemic hypothermia.
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Randomized Controlled Trial Clinical Trial
Hyperbaric oxygen in the treatment of acute ischemic stroke. A double-blind pilot study.
The effects of hyperbaric oxygen (HBO) therapy on humans are uncertain. Our study aims first to outline the practical aspects and the safety of HBO treatment and then to evaluate the effect of HBO on long-term disability. ⋯ Although the small number of patients in each group precludes any conclusion regarding the potential deleterious effect of HBO, we did not observe the major side effects usually related to HBO. Accordingly, it can be assumed that hyperbaric oxygen might be safe. We hypothesize that HBO might improve outcome after stroke, as we detected an outcome trend favoring HBO therapy. A large randomized trial might be required to address the efficacy of this therapy.
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Knowledge is limited about the effects of the Valsalva maneuver on cerebral circulation because of the poor temporal resolution of traditional cerebral blood flow measurements. The purpose of this study was to investigate changes in cerebral blood flow during the Valsalva maneuver and to explore its potential use for the evaluation of cerebral autoregulation. ⋯ These results demonstrated that in healthy humans the Valsalva maneuver causes characteristic changes in systemic blood pressure as well as in flow velocity in the middle cerebral artery, reflecting the sympathetic and cerebral autoregulatory responses, respectively. Analysis of these changes may provide an estimate of autoregulatory capacity.
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Intracranial hemorrhage is the most feared and lethal complication of oral anticoagulation. We review the frequency, predictors, and prognosis of this most common neurological complication of oral anticoagulation. ⋯ Both patient factors and anticoagulation intensity importantly influence the rate of anticoagulation-related intracranial hemorrhage. Patient-related risk factors for this complication overlap with those for ischemic stroke. The risk/benefit equation of anticoagulation for elderly, stroke-prone patients is complex and differs from that for younger patients. The absolute rate reduction (not the relative risk reduction) of ischemic stroke by anticoagulation is the critical issue and must offset accentuation of often lethal brain hemorrhage.
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A 2.9 degrees C reduction in the intraischemic rectal temperature of neonatal piglets is associated with less brain damage compared with animals with normothermic rectal temperatures. This investigation studied one potential mechanism for this observation: better maintenance of energy stores and less brain acidosis secondary to reduced metabolic activity associated with modest hypothermia. ⋯ Intraischemic modest hypothermia attenuates the severity of brain acidosis during and 30 minutes after ischemia compared with normothermic animals and supports the concept that attenuated brain acidosis is a potential mechanism by which hypothermia may reduce ischemic brain damage.