SUMMARY To study the effects of antithrombotic therapy in experimental stroke, we have characterized a baboon model of acute cerebrovascular thrombosis. In this model an inflatable silastic balloon cuff has been implanted by transorbital approach around the right middle cerebral artery (MCA), proximal to the take-off of the lentlculostriate arteries (LSA). Inflation of the balloon for 3 hours in six animals produced a stereotypic sustained stroke syndrome characterized by contralateral hemiparesis. An Infarction volume of 3.2 ± 1 . 5 cm 3 in the ipsilateral corpus striatum was documented by computerized tomographic (CT) scanning at 10 days following stroke induction and 3.9 ± 1 . 9 cm 3 (n = 4) at 14 days by morphometric Deuropathotogic determinations of brain specimens fixed in situ by pressure-perfusion with 10% buffered formalin.Immediate pressure-perfusion fixation following deflation of the balloon was performed in 16 additional animals given Evans blue dye intravenously prior to the 3 hour MCA balloon occlusion. Light microscopy and transmission electron microscopy consistently confirmed the presence of thrombotic material occluding microcirculatory branches of the right LSA in the region of Evans blue stain, but not those of the contralateral corpus striatum.When autologous '"in-platelets were infused intravenously in four animals from the above group prior to the transient 3 hour occlusion of the right MCA, gamma scintillation camera imaging of each perfused-flxed whole brain demonstrated the presence of a single residual focus of '"in-platelet activity involving only the Evans blue-stained right corpus striatum. Focal right hemispheric activity was equivalent to 0.55 ± 0.49 ml of whole blood, and the occlusion score derived from histologic examination of the microcirculatton of the Evans blue-stained corpus striatum averaged 34.8 ± 2.8. Similar "'in-platelct imaging and histologic scoring experiments carried out hi four animals pretreated with the antithrombotic combination heparin and tidopidine showed marked reduction of both "'in-platelet activity (0.01 ± 0.03 ml vs. 0.55 ± 0.49 ml; p < 0.01) and thrombotic occlusion of the microcirculation (10.8 ± 7.4 units vs. 34.8 ± 2.8 units; p < 0.01) in the right corpus striatum following 3 hours of MCA occlusion. In separate control experiments "'inlabeled autologous platelets were infused after the 3 hour period of right MCA occlusion and subsequent balloon deflation hi two animals; no focus of '"in-platelet activity was demonstrated in fixed whole brain.We conclude that thrombi form in situ In the microcirculation of perforating branches of the LSA located in the ipsilateral corpus striatum following a 3 hour period of MCA occlusion and that these thrombi may be prevented when antithrombotic therapy is administered prior to MCA balloon occlusion. This model of acute thrombotic stroke may be useful to assess the safety and efficacy of thrombolytic therapies.
The cause of primary Meige syndrome is unknown, and although gender and age predilections are different from idiopathic torsion dystonia, most investigators consider Meige syndrome a variant of that disorder. Interest in the use of stereotactic brain surgery for refractory forms of dystonia is thus increasing. There is little experience with the use of deep brain stimulation (DBS) in focal dystonias, and reports of its use in Meige syndrome are very rare. We report on a case of Meige syndrome successfully treated with bilateral pallidal DBS.
Rapid presurgical neuromagnetic localization of the somatosensory cortex was performed successfully on five patients with a large-array biomagnetometer by a protocol called magnetic source imaging (MSI). Determination of the location of the central sulcus is important in assessing operative risk and determining the optimal operative approach to structural lesions in the vicinity of the motor strip. The use of magnetic resonance imaging anatomical methods and intraoperative visual identification can be imprecise, whereas invasive localization prolongs operative time, adds cost, and entails added risk. Until the recent development of large-array biomagnetometer systems, neuromagnetic localization of the central sulcus had been demonstrated in research but was so time consuming and laborious as to preclude routine clinical use. In this study, the validity of MSI localizations was confirmed intraoperatively by direct cortical recording of somatosensory evoked potentials and/or direct motor stimulation. Complete agreement was found between MSI and intraoperative mapping in locating the central sulcus. Objective confirmations considered together with the speed and reliability of the procedure and with the presurgical availability of the results suggests the potential utility of MSI for routine surgical planning.
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