Cerebral vasospasm is a common cause of ischemia and death in patients suffering from cerebral hemorrhage, most notably subarachnoid hemorrhage (SAH), and it usually occurs 4-14 days after the initial episode of bleeding. Many mediators of cerebral vasospasm (CVS) have been proposed, but at this time the pathogenesis of CVS is poorly understood, and oxyhemoglobin is thought to be the principal pathogenic agent. / This project was designed to examine the effects of oxyhemoglobin on the vascular tone of the middle and basilar cerebral arteries in vitro and to evaluate the validity of using bovine vessels as an animal model of the human cerebral vasculature in which to study cerebral vasospasm. Human vessels were studied in parallel with the bovine arteries to test the validity of the animal model. To further evaluate the model, some experiments were also carried out on canine vessels, because the dog has frequently been used for cerebrovascular studies in the past. / The cow is a better model of the human cerebral vasculature than the dog. Arteries respond to a variety of vasoactive stimuli, in a manner closely resembling human vessels, and can be induced into a prolonged vasospastic state by exposure to oxyhemoglobin. Vasospasm in all three species was independent of endothelial status, functional innervation, or morphological evidence of atherosclerosis. Vasospasm could not be prevented by diltiazem, nicardipine or ascorbic acid, but was partially reversed in some samples by verapamil. Bovine vessels would appear to be exceptionally useful for studies designed to test pharmacological agents for the prevention or therapy of post-hemorrhagic vasospasm and also to determine the pathophysiological mechanisms involved.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.22819 |
| Date | January 1994 |
| Creators | Tretiak, Tania |
| Contributors | Zorychta, E. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Pathology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001441152, proquestno: MM05643, Theses scanned by UMI/ProQuest. |
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