Stroke; a journal of cerebral circulation
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We previously showed that treatment with a competitive N-methyl-D-aspartate (NMDA) receptor antagonist GPI-3000 (GPI) improved short-term physiological recovery after incomplete global cerebral ischemia complicated by dense acidosis. We tested the hypothesis that GPI administered after resuscitation from cardiac arrest would improve a more long-term recovery as measured by neurobehavioral assessment and neuropathology 4 days after resuscitation. ⋯ Contrary to results seen in experimental global and focal cerebral ischemia, in which NMDA receptor antagonism may improve responses to injury, receptor antagonism with GPI does not improve brain outcome after cardiac arrest and resuscitation in the dog. Behavioral and histological outcomes both were worsened by GPI treatment at two doses, and mortality was higher relative to saline control treatment. We speculate that systemic drug effects, as well as potential neurotoxicity of the drug under ischemic conditions, may be responsible for the deleterious outcomes observed in our cardiac arrest model.
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Vertebrobasilar dolichoectasia (VBD) may produce symptoms by direct compression of cranial nerves or the brain stem, by obstructive hydrocephalus, or by ischemia in the vertebrobasilar arterial territory. This study was undertaken to examine and characterize clinical and imaging findings in patients with stroke associated with VBD and compare these data with those for patients with VBD who did not have a stroke. ⋯ In patients with VBD, superimposed atheromatous changes of the posterior circulation may have an important role in precipitating ischemia. However, other factors related to the severity of the dolichoectasia also favor ischemia and in some cases are the only factors responsible.
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Correlation of MRI findings with various vascular pathologies has rarely been attempted in patients with lateral medullary infarction (LMI). The aim of the present study was to correlate the diverse MRI lesions with the vascular lesions seen on conventional cerebral angiography in LMI. ⋯ Our data suggest that the heterogeneous MRI lesions (and consequent clinical syndromes) of LMI are correlated with diverse angiographic findings, which in turn are due to different pathogenic mechanisms: etiology, location and size of the involved vessels, speed of the lesion development, and status of collateral channels. Generally, infarcts related to multiple vessel involvement, dissection, and poor collateral circulation are larger than those associated with single-vessel disease, long-standing atherothrombosis/cardiac embolism, and good collateralization.
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Moderate elevations of brain temperature, when present during or after ischemia or trauma, may markedly worsen the resulting injury. We review these provocative findings, which form the rationale for our recommendation that physicians treating acute cerebral ischemia or traumatic brain injury diligently monitor their patients for incipient fever and take prompt measures to maintain core-body temperature at normothermic levels. ⋯ The acutely ischemic or traumatized brain is inordinately susceptible to the damaging influence of even modest brain temperature elevations. While controlled clinical investigations will be required to establish the therapeutic efficacy and safety of frank hypothermia in patients with acute stroke, the available evidence is sufficiently compelling to justify the recommendation, at this time, that fever be combatted assiduously in acute stroke and trauma patients, even if "minor" in degree and even when delayed in onset. We suggest that body temperature be maintained in a safe normothermic range (eg, 36.7 degrees C to 37.0 degrees C [98.0 degrees F to 98.6 degrees F]) for at least the first several days after acute stroke or head injury.
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Comparative Study
Comparison of the use of medical resources and outcomes in the treatment of aneurysmal subarachnoid hemorrhage between Canada and the United States.
Using data from a randomized trial of tirilazad mesylate, we assessed the differences between Canada and the United States in the use of medical resources and outcomes in the treatment of aneurysmal subarachnoid hemorrhage during the first 90 days after admission to the hospital. ⋯ For patients admitted to the study in good neurological condition, the apparent difference in length of stay between Canada and the United States was caused by a shift in the sites of formal care rather than to the length of this care. For those admitted in poor neurological condition, both the length and sites of care differed between the two countries. No significant difference in outcomes appeared to justify these differences in the use of medical resources.