Stroke; a journal of cerebral circulation
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Comparative Study
Mechanisms of vasodilation of cerebral vessels induced by the potassium channel opener nicorandil in canine in vivo experiments.
Nicorandil, a potent antianginal agent characterized as a potassium channel opener, could produce cerebrovascular dilation in in vitro studies. Our aim was to investigate the pharmacologic response to the topical application of nicorandil on the vasomotor tone of pial vessels in vivo. To elucidate its mechanism, we also studied the inhibitory action of methylene blue and glibenclamide against nicorandil-induced vasodilation. ⋯ Our in vivo study demonstrates that topical application of nicorandil dilates both pial arterioles and venules in a concentration-dependent manner and suggests that the mechanisms of such actions are most likely due to both cyclic GMP-mediated vascular smooth muscle dilation and the regulation of K+ flux.
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Review Comparative Study
Definition of initial grading, specific events, and overall outcome in patients with aneurysmal subarachnoid hemorrhage. A survey.
Scientific communication in medicine can be effective only if reports are based on unequivocal criteria for clinical conditions or specific diagnoses. ⋯ Reports about subarachnoid hemorrhage require closer scrutiny before publication to ascertain whether the conclusions about specific outcome events are based on unequivocal criteria.
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Comparative Study
Blood flow velocity and vasomotor reactivity in patients with arteriovenous malformations. A transcranial Doppler study.
A large percentage of patients with a cerebral arteriovenous malformation (AVM) show focal neurological signs or have a history of intracranial hemorrhage. The present study used transcranial Doppler sonography to assess the clinical significance of hemodynamic disturbances in the intracranial arteries of patients with an AVM. ⋯ Our results suggest two distinct relations between transcranial Doppler results and clinical findings: (1) Relatively normal vasomotor reactivity values in arteries ipsilateral to an AVM indicate a high-pressure AVM with an increased risk of hemorrhage. (2) A strongly pathological vasomotor reactivity in arteries ipsilateral and contralateral to an AVM indicates a low-pressure AVM with a higher prevalence of hemodynamically induced neurological signs.
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Comparative Study
Therapeutic time window and dose response of the beneficial effects of ketamine in experimental head injury.
The aim of this study was to determine the time and dose response of the therapeutic effects of the N-methyl-D-aspartate receptor antagonist ketamine in experimental head injury. ⋯ We conclude that 180 mg/kg IP ketamine was effective in ameliorating neurological dysfunction after head trauma in rats when the administration time was delayed for 1 hour to 2 hours but not after 4 hours. When given at 1 hour after head trauma, ketamine at 120 mg/kg but not 60 mg/kg is effective in reducing neurological damage after head trauma.