Recovery Time between Multiple Mild Photothrombotic Strokes Affects Brain Damage
| atmire.migration.oldid | 1902 | |
| dc.contributor.advisor | Tuor, Ursula | |
| dc.contributor.author | Deng, Qinbo | |
| dc.date.accessioned | 2014-02-12T16:47:15Z | |
| dc.date.available | 2014-03-15T07:00:21Z | |
| dc.date.issued | 2014-02-12 | |
| dc.date.submitted | 2014 | en |
| dc.description.abstract | Prior to stroke, patients often experience a transient ischemic attack (TIA) or minor stroke with a high recurrence within the first week. The initial episode of ischemia, traditionally considered to causing little permanent damage to brain, is poorly understood for its role in subsequent ischemic events. We hypothesized that despite functional recovery following TIA/minor stroke, there can be sparse tissue damage that alters the brain response to a secondary mild stroke, with the final tissue fate being dependent on the recovery time between recurrent strokes. Thus, the first objective of this thesis was to establish a rat model of TIA/minor stroke using modifications of a phothothrombotic (PT) occlusion of the cerebral microvasculature. The effect of varied light intensities and illumination durations were examined on the severity of stroke. Multiple sequences (T2, Apparent Diffusion Coefficient (ADC), Perfusion Weighted Imaging) of Magnetic Resonance Imaging (MRI) were performed to evaluate the tissue damage. We found that a 5-min illumination at approximate 35,000 Lux of light intensity was optimal to produce a mild tissue damage associated with a transient ischemia measured by Laser-Doppler Flowmetry. The T2 signatures measured at 24h were good predictors of graded ischemic injury confirmed by histology. Compared with ADC measures, T2 provided a better diagnosis of mild damage (scattered necrosis). The second objective was to use this modified PT model to produce a recurrent stroke and to investigate if the outcome differed depending on the interval between insults – i.e. 1day, 2days, 3days and 1week. Using this novel model, we demonstrated that a mild recurrent stroke produced more deleterious injury with acute intervals (1 day to 3 day) than a subacute one (1week). This enhancement of damage was characterized by an increase of T2 and a decrease of perfusion. In contrast, the 1week interval produced tissue damage similar to a single mild stroke, associated with similar changes of MR. Together, our finding revealed a temporal change of brain susceptibility to ischemia, implying the importance of early treatment after TIA/minor stroke for reduction of damage with stroke recurrence. | en_US |
| dc.identifier.citation | Deng, Q. (2014). Recovery Time between Multiple Mild Photothrombotic Strokes Affects Brain Damage (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27565 | en_US |
| dc.identifier.doi | http://dx.doi.org/10.11575/PRISM/27565 | |
| dc.identifier.uri | http://hdl.handle.net/11023/1374 | |
| dc.language.iso | eng | |
| dc.publisher.faculty | Graduate Studies | |
| dc.publisher.institution | University of Calgary | en |
| dc.publisher.place | Calgary | en |
| dc.rights | University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. | |
| dc.subject | Neuroscience | |
| dc.subject | Psychology--Experimental | |
| dc.subject.classification | Animal Model | en_US |
| dc.subject.classification | Recurrent Stroke | en_US |
| dc.subject.classification | Transient Ischemic Attack | en_US |
| dc.subject.classification | Magnetic Resonance Imaging | en_US |
| dc.subject.classification | Apparent Diffusion Coeficient | en_US |
| dc.subject.classification | T2-weighted Imaging | en_US |
| dc.subject.classification | Diffusion-weighted Imaging | en_US |
| dc.subject.classification | Perfusion-weighted Imaging | en_US |
| dc.subject.classification | Scattered Necrosis | en_US |
| dc.subject.classification | Cerebral Blood Flow | en_US |
| dc.title | Recovery Time between Multiple Mild Photothrombotic Strokes Affects Brain Damage | |
| dc.type | master thesis | |
| thesis.degree.discipline | Neuroscience | |
| thesis.degree.grantor | University of Calgary | |
| thesis.degree.name | Master of Science (MSc) | |
| ucalgary.item.requestcopy | true |