Medicine and Health Sciences Commons^™

Acquired Bracket Pellicle Modulation Via Exposure To Histatin 3, Niklas W. Neilson

Electronic Thesis and Dissertation Repository

Objectives: To investigate the effect of histatin 3 on the protein pellicle formation on the orthodontic bracket surface.

Methods: Our study consisted of 4 sample groups. A sample of human parotid saliva without histatin functioned as a control group. Other groups were immersed with or without histatin 3 and human parotid saliva. Each group was incubated for 2 hours in their respective substrate at 37°C. The acquired pellicle from each group was harvested, then analyzed with SDS-PAGE and LC-ESI-MS/MS.

Results: Thirty-nine proteins were identified in the control group, 18 were identified in group 2, and 21 were identified in group …

Identifying And Targeting Cancer Stem Cells In Colorectal Cancer, Amber Harnett

Electronic Thesis and Dissertation Repository

The cancer stem cell hypothesis posits that cancer stem cells (CSCs) are the driving force behind tumour progression and metastasis, making them ideal therapeutic targets. Previous research identified Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) as a marker of CSCs in colorectal cancer (CRC). However, it is not known whether more than one CSC population exists in CRC. Identifying and targeting CSCs in CRC is important for effective treatment of cancer patients. Here, I show that Keratin-19 (K19) labels intestinal CSCs in mouse tumours that recapitulate the early stages of CRC. Moreover, selective ablation of Lgr5 has no effect on tumour …

The Mitochondrial Calcium Uniporter Regulator 1 (Mcur1) Matrix Domain Is A Self-Associated Multimer Sensitive To Divalent Cations, Naveed Siddiqui

Electronic Thesis and Dissertation Repository

Mitochondria are primarily appreciated for the generation of adenosine triphosphate (ATP), a chemical store of energy required by all cells. These organelles, however, also play key roles in apoptosis, autophagy and shaping cytosolic calcium (Ca²⁺) signaling via Ca²⁺ uptake into the mitochondrial matrix. This Ca²⁺ uptake is mediated chiefly via the mitochondrial Ca²⁺ uniporter (MCU), an inner mitochondrial membrane protein that oligomerizes to form a Ca²⁺ selective pore. MCU is regulated by several protein binding partners, including the recently identified MCU regulator-1 (MCUR1). MCUR1 stabilizes a higher order MCU heterocomplex through interactions with MCU …

Normalizing Masculinity: Explaining Processes, Factors, And Contexts That Influence How Rural Male Farmers Seek Health Information In Southwest Ontario, Bradley C. Hiebert

Electronic Thesis and Dissertation Repository

Disproportionately high mortality and morbidity rates experienced by rural men are often related to the high prevalence of rural male farmers (RMFs) who are consistently exposed to chemicals, animal waste, and dust, or injured or killed while working. This dissertation aimed to explain processes by which RMFs seek health information (HI), and how these processes are influenced by rural social, cultural, political, and geographical factors.

Three studies were conducted as part of this dissertation. The first study was a literature review that explored the relationship between rural men’s health, health information seeking (HIS) theory, and masculinity theory. The second study …

Virtual Reality Simulation Of Glenoid Reaming Procedure, Mohammadreza Faieghi

Electronic Thesis and Dissertation Repository

Glenoid reaming is a bone machining operation in Total Shoulder Arthroplasty (TSA) in which the glenoid bone is resurfaced to make intimate contact with implant undersurface. While this step is crucial for the longevity of TSA, many surgeons find it technically challenging. With the recent advances in Virtual Reality (VR) simulations, it has become possible to realistically replicate complicated operations without any need for patients or cadavers, and at the same time, provide quantitative feedback to improve surgeons' psycho-motor skills. In light of these advantages, the current thesis intends to develop tools and methods required for construction of a VR …

Differences In Quadriceps Muscle Layer Thickness (Qmlt) And Contributing Risk Factors To Muscle Mass In Community-Dwelling And Institutionalized Older Adults, Nesrine Cheikh

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Sarcopenia, a major concern in the older adult population, is defined as age-related loss of muscle mass and strength. Quadriceps muscle layer thickness (QMLT) measured using ultrasonography (US) is a newly-validated tool to measure muscle mass, which can be used to identify sarcopenic individuals. Our objective was to determine the association of factors such as handgrip strength (HGS), protein intake, nutritional status (via Subjective Global Assessment-SGA) and fat mass (FM) percentage with QMLT size (measured by US) in community-dwelling and institutionalized older adults. Additionally, we aimed to understand how perceived food intake of protein-rich foods could have an impact actual …

An Exploration Of The Nursing Leaders’ Experiences Addressing Indigenous Health In University Undergraduate Nursing Programs In Ontario, Danae Coggins

Electronic Thesis and Dissertation Repository

Introduction. Although there are serious health inequities experienced by Indigenous people compared to non-Indigenous people in Canada and racism and discrimination continues to be rife in health care environments, there remains a general lack of attention to Indigenous health (IH) in health professional education programs. In response, the Truth and Reconciliation Commission (TRC) has recommended this be addressed within health profession education, including nursing (Truth and Reconciliation Canada, 2015). However, there is a paucity of evidence describing the challenges and facilitators to incorporating IH into nursing education.

Methodology and Methods. This qualitative study employs interpretive description approaches informed by …

Evaluation Of Perioperative Peripheral Nerve Injury In Cardiac Surgery Using A Novel Automated Ssep Monitoring Device, Satoru Fujii

Electronic Thesis and Dissertation Repository

INTRODUCTION: The high incidence of peripheral nerve injury (PNI) in conventional cardiac surgery (CCS) is believed to result from mechanical injury during sternotomy and/or retraction of the sternum. Minimally invasive cardiac surgery (MICS) is a newly developed type of cardiac surgery which does not require sternotomy or retraction of the sternum. Since surgery related PNI can lead to serious problems for both the patients and care providers, the incidence and details of PNI in cardiac surgery needs to be investigated. OBJECTIVE: To compare the degree of nerve injury in MICS and CCS using somatosensory evoked potential (SSEP) signals. …

A Randomized Controlled Trial Of A Modified Cystoscopy Technique, Khalil Hetou

Electronic Thesis and Dissertation Repository

Introduction

Pain, anxiety and embarrassment are well documented feelings in patients undergoing ambulatory diagnostic cystoscopy. In this study, we explored utilizing Peak-end theory in improving pain perception in patients undergoing diagnostic cystoscopy.

Materials and Methods

We conducted a randomized clinical trial at the London Health Sciences Center for patients undergoing an ambulatory diagnostic cystoscopy for the first time. Males and females as well as allocation ratios were 1:1. The control arm received a standard cystoscopy. In the intervention arm the cystoscope was left for additional 2 minutes without further manipulation in the bladder before scope removal. The primary outcome was …

Retrospective Motion Correction In Magnetic Resonance Imaging Of The Brain, Patricia Johnson

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is a tremendously useful diagnostic imaging modality that provides outstanding soft tissue contrast. However, subject motion is a significant unsolved problem; motion during image acquisition can cause blurring and distortions in the image, limiting its diagnostic utility. Current techniques for addressing head motion include optical tracking which can be impractical in clinical settings due to challenges associated with camera cross-calibration and marker fixation. Another category of techniques is MRI navigators, which use specially acquired MRI data to track the motion of the head.

This thesis presents two techniques for motion correction in MRI: the first is …

Effect Of Bacterial Superantigens On The Magnitude And Breadth Of Influenza-Specific Cd8+ T Cell Responses, Courtney Meilleur

Electronic Thesis and Dissertation Repository

Severe cases of influenza A virus (IAV) infection are often complicated by concomitant bacterial pneumonia or sepsis. Many bacterial species are capable of producing potent immunomodulators called superantigens (SAgs), which have the potential to interfere with cell-based antiviral immune mechanisms. I asked what effects bacterial SAgs have on both the magnitude and the breadth of antiviral CD8⁺ T cell (TCD8⁺) responses. Surprisingly, administration of SAgs to mice shortly before or after vaccination with IAV increased the number of primary TCD8⁺ responding to select IAV-derived epitopes. T cell receptor staining of these SAg-augmented populations revealed expression of …

Examining Climate Change-Health Nexus In Ghana, Lucia Kafui Hussey

Electronic Thesis and Dissertation Repository

Climate change is one of today’s most pressing global issues with its physical, biological and social impacts widely recognized. One area of concern is its potential health consequences. The postulated health effects from climate change are far-reaching that climate change induced health risks are signaled as the most pressing problems to public health in the 21^st century. Although developing countries such as Ghana had been suggested as a vulnerable hotspot for the health consequences of climate change, there is a paucity of empirical research on climate change and its health linkages in the country.

The purpose of this dissertation …

Measuring The Efficiency Of The Living Kidney Donor Candidate Evaluation Process, Steven Habbous

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Background: Living kidney donation is the ideal treatment for many patients with kidney failure. However, the living donor evaluation process has been criticized by patients and healthcare providers as inefficient. In the present research, we evaluated the inefficiency of the living donor evaluation process.

Methods: We conducted a scoping review of the literature and obtained data from large administrative datasets (1256 living donors) and medical chart review (849 prospectively recruited living donors across 12 transplant centres plus retrospective analysis of 1065 living donor candidates from a single centre).

Results: The median time to complete the entire evaluation was 9-11 months …

Social Inclusion For Women Experiencing Homelessness, Jenna Richards

Electronic Thesis and Dissertation Repository

Background: People experiencing homelessness have been described as one of the most socially excluded groups in society due to their inequitable access to basic necessities (Everett 2009; Labonte, 2004). Particular consideration regarding social inclusion should be given to the unique vulnerabilities of sub-populations of those experiencing homelessness, such as women (Wesely & Wright, 2005) due to their increased rates of ‘hidden homelessness’ (Walsh et al., 2009) and experiences of violence and discrimination (Roschelle, 2017; Weiser et al., 2009). Community participation, particularly sports activities, have been cited as one method towards increasing social inclusion among people experiencing homelessness. However, differential access …

Acromial Insufficiency Fractures In Reverse Total Shoulder Arthroplasty: A Biomechanical Study, Alicia Kerrigan

Electronic Thesis and Dissertation Repository

Reverse total shoulder arthroplasty (RTSA) is increasingly utilized in the aging population, with a growing list of surgical indications including rotator cuff tear arthropathy, proximal humerus fractures, and revision arthroplasty. Acromial insufficiency fractures following RTSA are poorly understood, difficult to diagnose, and associated with inferior clinical outcomes. There is limited knowledge in the literature regarding the etiology of post-operative acromial fractures. The purpose of this study is to evaluate the role of implant parameters on acromial strain following RTSA.

Using a cadaveric model, a custom designed modular RTSA system was implanted that allowed for evaluation of modifiable parameters including glenoid …

Investigating The Use Of M-Health For Learning And Clinical Training By Medical Students In Ghana, Abdul M. Sulley

Electronic Thesis and Dissertation Repository

There is a challenge with healthcare access in most developing countries. With the high rate of mobile technology penetration in these countries, there is a strong belief that mobile technology can help address this and other health system and education challenges. This study investigated how clinical year medical students in Ghana used m-health and with what outcomes. This was a mixed-methods study to assess what technologies students used, what the impact of use was, what enablers and barriers they encountered, what factors explained m-health adoption and what the attitudes of students, staff and faculty members were towards m-health use. The …

Investigating The Practical And Clinical Effectiveness Of Applying Current Steering To Deep Brain Stimulation For Parkinsonian Gait Therapy, Daphne Hui

Electronic Thesis and Dissertation Repository

Multiple neural network integration, influence of bradykinesia and rigidity, and bias of upper limb symptom improvement during deep brain stimulation implementation may attribute to the variable responsiveness of Parkinsonian gait therapy. Current steering (CS) addresses variability through fractionating current to fine-tune the stimulation field shape. It was hypothesized that CS would exhibit greater gait improvements and lower the total electrical energy delivered (TEED), which reduces power consumption and battery drainage. Divisions of 70/30 and 50/50 and single-contact stimulation modelled CS and conventions, respectively. Overall ambulation improved with TEED reduction; further, bilateral CS improved step time and length but left CS …

Applications Of Ct Perfusion-Based Triaging And Prognostication In Acute Ischemic Stroke, Eric A. Wright

Electronic Thesis and Dissertation Repository

CT Perfusion (CTP) is a minimally invasive imaging technique that aids acute ischemic stroke (AIS) triage and prognostication by determining tissue viability based on hemodynamic parameters. The goals of this research are to determine: 1) CTP thresholds for estimation of infarct and penumbra volume, 2) how CTP scan duration impacts infarct and penumbra volume estimates, and 3) reliability of CTP for predicting functional outcomes following intra-arterial therapy (IAT).

Chapter 2 introduced an experimental study for determining ischemia-time dependent thresholds for brain infarction using multimodal imaging in a porcine stroke model that is easier to implement than previous large animal stroke …

Exploring Social Cohesion Among Syrian Refugees In Canada: A Secondary Analysis, Sara Calvert

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BACKGROUND: As a result of the ongoing crisis in Syria, more than 11 million people have been displaced or killed over the past seven years (Mercy Corps, 2018). Despite efforts by the Canadian government to increase refugee uptake and promote social cohesion, refugees may still face negative resettlement experiences (Galabuzi, 2006; McCoy, Kirova, & Knight, 2016). Exploring how Syrian refugees have experienced social cohesion within their first year in Canada may help to address resettlement needs.

METHODS: This study was a secondary analysis on data collected from the Housing Education for Syrian Refugees and their Landlords study, which evaluated the …

Investigating The Role Of Endogenous Atf4 Upregulation On Neuronal Glutathione Level, Fatemeh Mirshafiei

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ATF4 is a transcription factor that is activated in response to integrated stress response (ISR). In neurons specifically, ATF4 has been suggested to act as a pro-apoptotic transcription factor. The expression of ATF4, as well as its downstream gene targets have been implicated in both in vivo and in vitro models of Alzheimer’s and Parkinson’s Disease. However, the mechanism by which ATF4 promotes cell death remains unclear. It was previously shown that overexpression of ATF4 in primary cortical neurons caused a reduction in glutathione levels, resulting in oxidative stress-induced cell death. The aim of this project was to investigate whether …

Conceptual Disorganization And Redistribution Of Resting State Cortical Hubs In Drug-Naive First Episode Psychosis: A 7t Functional Magnetic Resonance Imaging Study, Avyarthana Dey

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Network level dysconnectivity has been studied in positive and negative symptoms of schizophrenia. Conceptual disorganization (CD) is a symptom which predicts impaired real-world functioning. Systematic reviews have reported aberrant connectivity in formal thought disorder, a construct related to CD. However, no studies have investigated whole-brain functional correlates of CD in psychosis. We sought to investigate brain regions explaining the severity of CD in patients with first-episode psychosis (FEPs) compared with healthy controls (HCs). We computed whole-brain binarized degree centrality maps of 31 FEPs, 25 HCs and characterized the patterns of network connectivity in the two groups. In FEPs, we related …

The Role Of Tbx3 In Early Breast Cancer Progression, Milica Krstic

Electronic Thesis and Dissertation Repository

TBX3 is a transcriptional regulator involved in embryonic development and in tumorigenesis of several cancer types. There are two isoforms of TBX3 (TBX3iso1 and TBX3iso2) with different DNA binding domains. The large-scale functional roles of TBX3iso1 and TBX3iso2 were characterized in a breast cancer context. Both TBX3 isoforms induced invasiveness and an epithelial-to-mesenchymal (EMT) phenotype. Coupling data from genome-wide ChIP-array and RNA-Seq studies provided a novel list of genes regulated by each isoform. Both TBX3 isoforms regulate expression of several EMT-related genes, including SLUG and TWIST1. Importantly, TBX3 is a direct regulator of SLUG, and SLUG expression is required for …

Cognitive Impairment And The Mediterranean Diet: A Canadian Perspective, Ivan Culum

Electronic Thesis and Dissertation Repository

Global life expectancy has increased steadily over the past century and is projected to continue increasing. Life expectancy increases are co-occurring with a reduction of fertility rates in many economically developed countries, which is resulting in an aging population, meaning that the proportion of older adults within the total world population will continue to increase. This is of particular concern as there is a rise of chronic neurodegenerative diseases among older adults, such as dementia, where the number of global deaths more than doubled since the turn of the century, making dementia the fifth leading cause of death worldwide. Dementia …

Healthy And Happy: Creating And Evaluating A Catalyst To Improve The Health Of University Students Via An Online Training System, Gillian E. Mandich

Electronic Thesis and Dissertation Repository

Increasingly, university students are facing unique, significant physical and mental health challenges. Additionally, they are spending more and more of their time online and are using online platforms to access mental health resources; consequently, there is a timely opportunity to explore the potential of online happiness interventions, specifically with video, to improve happiness among university students. Evidence suggests that improved happiness relates to improved physical health, mental health, and academic outcomes.

The purpose of this research was to test if an online happiness intervention, using videos to boost happiness, can increase self-reported happiness among university students. The primary outcome was …

In Vivo Tracking Of Tumour Associated Macrophages In Breast Cancer With Magnetic Resonance Imaging, Ashley V. Makela

Electronic Thesis and Dissertation Repository

Introduction: The environment in which a tumour exists and functions is called the tumour microenvironment (TME). In breast cancer, the presence of tumour associated macrophages (TAMs) in the TME is associated with tumour aggressiveness and poor outcomes. Despite evidence for a link between TAM content and outcome, there are few strategies to measure TAMs and no in vivo approach. Iron or fluorine-19 (¹⁹F)-based MRI can be used to detect macrophages post intravenous injection of either an iron or perfluorocarbon (PFC) agent. Iron-based MRI is sensitive but difficult to quantify. ¹⁹F MRI is specific and signal is proportional …

Choice Of Implant Filler In Breast Reconstruction: A Study Of The Cost-Effectiveness Of Saline And Silicone Implants, Kathleen Nelligan

Electronic Thesis and Dissertation Repository

Breast reconstruction following mastectomy is increasing and implant-based breast reconstruction is the most common surgical approach. Saline and silicone implants have different cost and complication profiles and it is unclear which is the more cost-effective option. A systematic review of the literature was undertaken to summarize the quality of life data in breast reconstruction, specifically, previously published health state utility values relevant to breast reconstruction. In addition, a cost-utility analysis was undertaken from the perspective of the third-party payer, accounting for the most common complications associated with saline and silicone implants. This demonstrated that despite the increased initial cost of …

Aggregate Morbidity And Mortality Of Defunctioning Loop Ileostomy Fro Formation To Closure: A Large Population Retrospective Cohort Analysis, Mei Yang

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There is evidence that defunctioning loop ileostomies (DLIs) are associated with decreased risk of clinically significant anastomotic leaks, but at what cost? This population-based retrospective cohort study used administrative data to investigate differences in outcomes between patients undergoing low anterior resection with and without DLIs. We included all adult patients undergoing low anterior resection from 2002 to 2014 and identified outcomes within 30-days to 2-year of the index surgery. Outcomes included hospital readmission, reoperation, major complications, mortality, bleeding, and ileostomy reversal. DLIs were associated with significantly worse outcomes after low anterior resection, including increased risk of major complication, acute kidney …

Tibiotalar Arthrodesis: Development Of A Novel Jig And Alignment Guide, Adam Mathew Ropchan

Electronic Thesis and Dissertation Repository

Tibiotalar arthrodesis is a surgical procedure, used for the treatment of end-stage ankle arthrosis and instability. There are dozens of described procedures in the literature, all with varying rates of success. Two of the most common reasons for reoperation in tibiotalar arthrodesis are nonunion and infection; few studies have established any associations between patient/surgical factors and reoperation for nonunion and infection.

The first part of this thesis focuses on determining the rate of reoperation to the ipsilateral lower limb and if any patient/surgical factors are associated with reoperation for nonunion and infection. The second part of this thesis turns attention …

Diagnostic Ultrasound In The Measurement Of Cortical Bone Thickness In Porcine Mandibular Specimens, Diego Diaz Guerrero

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Introduction: Ultrasound (US) is a safe, non-invasive diagnostic method that has been used in various capacities in medicine and dentistry. Periodontal bone loss, bony dehiscence, and gingival recession have been reported as potential risks of orthodontic treatment in patients who have decreased buccal/labial bone thickness. US has the potential to aid in the diagnosis of patients at risk for these possible complications of orthodontic treatment. Purpose: To validate the use of a novel US device in the measurement of buccal cortical bone (BCB) thickness over roots in porcine mandibles. Materials and Methods: Jaw and cortical bone models were constructed and …

Medial Geniculate Projections To Auditory And Visual Cortex In Hearing And Deaf Cats, Benjamin Trachtenberg

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Following early-onset deafness, studies have demonstrated crossmodal plasticity, throughout “deaf” auditory cortex. Crossmodally reorganized auditory cortex shows increased dendritic spine density, which suggests increased numbers of axon terminals. I examined projections from the medial geniculate body (MGB) of hearing and early-deaf cats in order to reveal the distribution of synaptic boutons in the cortex, originating from MGB neurons. Anterograde fluorescent dextran tracers were deposited bilaterally in the MGB in order to label cortical axon terminals. Deafness resulted in axon terminal increases in visual cortex, and conservation of auditory axon terminal distribution. Visual areas PLLS and area 18 received increased projections …