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Virginia Commonwealth University

Theses and Dissertations

Traumatic brain injury

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Axon Initial Segment Integrity In Aging And Traumatic Brain Injury, Mazen M. Gouda Jan 2019

Axon Initial Segment Integrity In Aging And Traumatic Brain Injury, Mazen M. Gouda

Theses and Dissertations

According to the Center for Disease Control’s (CDC) report to the Congress, there are 2.2 million emergency department visits; 80,000 hospitalizations; and 50,000 deaths each year due to traumatic brain injury. Adults 65 years and older account substantially for the majority of the hospitalization and deaths. Over 70% of the traumatic brain injuries of the older adults are classified as mild to moderate; however, even with these milder injuries, older adults present with a significantly higher morbidity and mortality compared to all other age groups (LeBlanc et al., 2006). With that in mind, it seems essential to develop a deeper …


Effects Of Traumatic Brain Injury On Oxycodone Reinstatement And Physical Dependence, Neil B. Varshneya Jan 2016

Effects Of Traumatic Brain Injury On Oxycodone Reinstatement And Physical Dependence, Neil B. Varshneya

Theses and Dissertations

Epidemiological data indicate that patients who experience a traumatic brain injury (TBI) have an elevated risk of developing a substance use disorder (SUD), but the underlying neurobiological connections remain unclear. To further understand the relationship between TBI and SUD, we investigated the effects of TBI on the abuse-related effects of oxycodone in preclinical models. Our evaluation utilized a lateral fluid percussion injury of moderate severity in adult male Sprague-Dawley rats. In the first aim, we tested the hypothesis that moderate TBI increases the risk for relapse to an opioid use disorder as measured by reinstatement of lever-pressing behavior following extinction …


Post-Tbi Hippocampal Neurogenesis In Different Tbi Models, Kaushal S. Patel Jan 2016

Post-Tbi Hippocampal Neurogenesis In Different Tbi Models, Kaushal S. Patel

Theses and Dissertations

Traumatic brain injury (TBI) leads to short-term and long-term consequences that can cause many different life-long disorders. Studies of TBI have generally focused on the acute stage; however, it is now becoming important to investigate chronic responses following TBI as clinical reports of dementia and cognitive impairments have been linked to a history of TBI. Recent data have established that cognitive function is associated with hippocampal neurogenesis. Chronic injury induced changes in the brain may affect this endogenous process. Chronic responses following TBI include cell death pathways and inflammatory responses that are persistent in the brain for months to years …


Diffuse Traumatic Axonal Injury Within The Visual System: Implications For Visual Pathway Reorganization, Jiaqiong Wang Dec 2012

Diffuse Traumatic Axonal Injury Within The Visual System: Implications For Visual Pathway Reorganization, Jiaqiong Wang

Theses and Dissertations

Traumatic brain injury is a major health problem with much of its morbidity associated with traumatic axonal injury (TAI). To date, significant insight has been gained into the initiating pathogenesis of TAI. However, the specific anterograde and retrograde sequelae of TAI are poorly understood because the diffuse nature of TAI complicates data analysis. To overcome this limitation, we subjected transgenic mice expressing yellow fluorescent protein (YFP) within the visual system to central fluid percussion injury, and consistently generated diffuse TAI within the optic nerve that could easily be followed in the organized YFP positive fibers. We demonstrated progressive axonal swelling, …


The Role Of Calcineurin In Dendritic Remodeling And Epileptogenesis In A Rat Model Of Traumatic Brain Injury, John Campbell Feb 2012

The Role Of Calcineurin In Dendritic Remodeling And Epileptogenesis In A Rat Model Of Traumatic Brain Injury, John Campbell

Theses and Dissertations

Traumatic brain injury (TBI), a leading cause of death and disability in the United States, causes potentially preventable damage in part through the dysregulation of neural calcium levels. This dysregulation likely affects the activity of the calcium-sensitive phosphatase, calcineurin, with serious implications for neural function. To test this possibility, the present study characterized the role of calcineurin in a rat model of brain trauma, the lateral fluid percussion injury model. Golgi-Cox histochemistry revealed an acute post-TBI loss and delayed overgrowth of dendritic spines on principal cortical cells. The spine loss appeared to require calcineurin activity, since administering a calcineurin inhibitor, …


The Characterization Of The Anterograde And Retrograde Consequences Of Traumatic Axonal Injury In A Mouse Model Of Diffuse Brain Injury, John E. Greer Sep 2011

The Characterization Of The Anterograde And Retrograde Consequences Of Traumatic Axonal Injury In A Mouse Model Of Diffuse Brain Injury, John E. Greer

Theses and Dissertations

Traumatic axonal injury (TAI) is a consistent feature of (TBI) and is responsible for much of its associated morbidity. TAI is now recognized to result from progressive/secondary axonal injury, though much remains unknown in regards to the pathobiology and the long-term consequences of axonal injury. TAI has been described in the perisomatic domain, located within the neocortex following mild TBI, and within this domain has been linked to neuronal recovery, not neuronal cell death in the acute setting. Due to technical limitations, our understanding of the long-term fate of this neuronal population and the mechanisms responsible for permitting neuronal survival, …


Pathological Upregulation Of A Calcium-Stimulated Phosphatase, Calcineurin, In Two Models Of Neuronal Injury, Jonathan Elledge Kurz Jan 2006

Pathological Upregulation Of A Calcium-Stimulated Phosphatase, Calcineurin, In Two Models Of Neuronal Injury, Jonathan Elledge Kurz

Theses and Dissertations

Excitotoxic calcium influx and activation of calcium-regulated systems is a common event in several types of neuronal injury. This mechanism has been the focus of intense research, with the hope that a more complete understanding of how neuronal injury affects calcium-regulated systems will provide effective treatment options. This study examines one such calcium-stimulated enzyme, calcineurin, in the context of two common neurological pathologies, status epilepticus and traumatic brain injury.Status epilepticus was induced by pilocarpine injection. NMDA-dependent increases in calcineurin activity were observed in cortical and hippocampal homogenates. Upon closer examination, the most profound increases in activity were found to be …