Medicine and Health Sciences Commons^™

Carbohydrates And Fungal Toxin Exposure Influence The Vaginal Microbiota, Metabolome, And Reproductive Health Of Women, Stephanie L. Collins

Electronic Thesis and Dissertation Repository

The reproductive health of women is influenced by microorganisms and their metabolites, namely those representing the vaginal microbiota and those producing toxins that are ingested. To manipulate the vaginal microbiota toward a health-associated, Lactobacillusdominant state, an approach adopting prebiotic lactulose was taken. Using batch culture, lactulose supported Lactobacillus maintenance and positively altered metabolites, while not disrupting indigenous L. crispatus epithelial adherence. The vagina also harbours abundant glycogen, but initial assumptions that lactobacilli utilize it were incorrect. I have now shown that glycogen selectively stimulates organisms associated with dysbiosis and L. iners in a self-limiting manner. Other compounds such as environmental …

Prostate Cancer Microparticles In Men Undergoing Radical Prostatectomy, Malcolm James Dewar

Electronic Thesis and Dissertation Repository

Objectives: To determine changes in prostate microparticle (PMP) concentrations in men with prostate cancer (PCa) after digital rectal examination (DRE), after radical prostatectomy (RP), and at follow-up.

Materials and Methods: 22 men were recruited before RP. Four blood specimens were collected – baseline (specimen 1), post-DRE (specimen 2), immediately post-RP (specimen 3), and follow-up (specimen 4). Pre- and post-DRE urine was collected (Specimen A and B respectively). Flow cytometric analysis of biofluids was performed with fluorescent-labeled antibodies against prostate-specific membrane antigen (PSMA) and polysialic acid. Total MP (TMP) and dual positive (PMP) events per µl of plasma or urine were …

Liver X Receptor And Retinoid X Receptor In Cartilage Development And Homeostasis, Man-Ger Sun

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA) is a heterogeneous and multifactorial degenerative disease characterized by cartilage degradation in the joint. Available treatment options target symptoms but do not address the underlying issue of joint tissue degeneration. A better understanding of the molecular mechanisms maintaining cartilage health is essential for developing novel therapeutic strategies. Previous studies have shown the nuclear receptor Liver X Receptor (LXR) to possess protective roles against cartilage breakdown in OA, however the underlying mechanisms behind this process remain unknown. Since LXR regulates transcription by forming obligate heterodimers with another nuclear receptor, the Retinoid X Receptor (RXR), I hypothesized that LXR and …

Proteomic Characterization Of Human Multipotent Stromal Cells Secreted Proteins With Therapeutic Potential For Β-Cell Regeneration, Miljan Kuljanin

Electronic Thesis and Dissertation Repository

Novel strategies to stimulate the expansion of β-cell mass in situ are warranted for diabetes therapy. Cell-replacement therapies for the treatment of diabetes have become a focal point in recent years. Endogenous regeneration of β-cell mass has been demonstrated using human multipotent stromal cells (hMSC). However, the secretory factors responsible for initiating endogenous regeneration remain unknown. Successful large-scale proteomic applications to address these questions have been limited in part by difficulties in correctly selecting the appropriate methodologies. Thus, the goal of this thesis was a combination of assessing different proteomic workflows to facilitate investigation into hMSC biology, applying these methods …

Crispr Screen For Identification Of Kinases That Mediate Prostate Cancer Cell Invasion, Hamad Aldhafeeri

Electronic Thesis and Dissertation Repository

Metastasis is the primary cause of mortality in cancer patients. Inhibition of proteins that are involved in the regulation of metastasis are expected to suppress metastasis and represent treatment targets. Our focus is on prostate cancer metastasis and we have developed a novel high-throughput means of performing in vitro screens for regulators of prostate cancer metastasis. We propose to use a focused CRISPR library screen that will “knock out” all human kinases to determine which ones are responsible for prostate cancer metastasis. CRISPR is a potent genetic editing tool and was used to silence all kinases in prostate cells (BPH …

Exploiting Fission Yeast Genetic Interaction Data To Identify Disease-Specific Drug Targets For Tuberous Sclerosis Complex, Ashyad Rayhan

Electronic Thesis and Dissertation Repository

Tuberous sclerosis complex (TSC) is an inherited genetic disorder caused by loss-of-function mutations in either TSC1 or TSC2. Their respective gene products regulate the mechanistic target of rapamycin (mTOR) signaling pathway, which serves as an activator of cellular proliferation, metabolism, and cell survival. Orthologs of the TSC1 and TSC2 genes exist in a wide range of organisms, including the commonly used and genetically tractable model eukaryote, Schizosaccharomyces pombe. To better understand the functional roles of S. pombe tsc1 and tsc2, I exploited recent advances in genetic interaction biology to identify and characterize genes that modulate the phenotypic …

The Feasibility Of Square-Stepping Exercise As A Universal Intervention For Older Adults With Chronic Disease To Improve Cognitive And Physical Function, Erin M. Shellington

Electronic Thesis and Dissertation Repository

Square-stepping exercise (SSE) is a cognitive training program with a physical component. An instructor demonstrates a stepping pattern across a gridded mat and participants are required to memorize and repeat the patterns on their own. In community-dwelling older adults, SSE has demonstrated some benefits on global cognitive functioning (GCF), balance, functional fitness, and social interaction.

Aims: to investigate the feasibility and efficacy of SSE in varied populations and settings to improve mobility and cognition. Populations included older adults with: knee osteoarthritis (OA), type 2 diabetes mellitus (T2DM) and self-reported cognitive complaints (sCC), and those living in long-term care (LTC) …

A Clinico-Pathological Study Of The Structural And Functional Changes In The Retina And Optic Nerve Following Diabetic Retinopathy Treatments, Richard Filek

Electronic Thesis and Dissertation Repository

Diabetic retinopathy (DR) is the result of microvascular changes in the retina due to hyperglycemia which alter the blood-retinal barrier (BRB). The increased permeability of BRB results in the accumulation of extracellular fluid, the development of diabetic macular edema (DME) and capillary occlusion. Capillary occlusion results in retinal ischemia which increases vascular endothelial growth factor (VEGF) levels, increases vascular permeability and results in neovascularization in proliferative diabetic retinopathy (PDR) patients. The treatments clinically used for DR are panretinal photocoagulation (PRP) for PDR and injectable vascular endothelial growth factor inhibitors (anti-VEGFs) for DME.

The safety of PRP and anti-VEGF therapy on …

The Potential Role Of Cathelicidin Peptides For The Treatment Of Lower Respiratory Tract Infections, Brandon John Harrison Banaschewski

Electronic Thesis and Dissertation Repository

Bacterial pneumonia, one of the leading causes of hospitalization and mortality worldwide, is caused by the colonization of invasive bacteria in the airways, leading to pulmonary inflammation and lung dysfunction. The development of antibiotic resistant bacterial infections has limited the effectiveness of current therapeutics and is particularly concerning in the setting of chronic bacterial infections, such as observed in cystic fibrosis and ventilator-associated pneumonia. The development of novel therapeutics for the treatment of multi-drug resistant bacterial pneumonia is urgently needed.

The overall objective of this body of work was the development of a new therapeutic compound to treat multi-drug resistant …

Retinoic Acid Pathway Inhibition To Expand Human Hematopoietic Progenitor Cells With Islet Regenerative Capacity, Ruth Elgamal

Electronic Thesis and Dissertation Repository

Cellular therapy to induce islet regeneration is emerging as a novel treatment strategy for diabetes. Umbilical cord blood (UCB)-derived hematopoietic stem/progenitor cells (HSPC) isolated by high aldehyde dehydrogenase activity (ALDH^hi) reduce hyperglycemia after transplantation into streptozotocin (STZ)-treated NOD/SCID mice. However, UCB-derived ALDH^hi cells are rare and expansion without the loss of regenerative function is required. We hypothesized that BMS 493, an inverse retinoic acid receptor agonist, will prevent HSPC differentiation of HSPC during expansion, generating more ALDH^hi cells for therapy. ALDH^hi cells expanded for 6 days with BMS 493 showed a 2.70-fold-increase in ALDH^{hi …}

Brain Networks In People After A First Unprovoked Seizure, Kristin M. Ikeda

Electronic Thesis and Dissertation Repository

Background: A single unprovoked seizure occurs in up to 10% of the population. Some develop epilepsy, but the majority do not. Brain network changes are observed in people with epilepsy, but it is unknown if they are present after this first seizure. This study examines network connectivity after the first seizure to determine if any changes exist.

Methods: Twelve patients after a single unprovoked seizure and twelve age- and sex-matched healthy controls were recruited. All underwent 7T resting-state fMRI scanning. Whole brain and limbic, default mode and salience network connectivity were analyzed with graph theory.

Results: Baseline characteristics were similar …

Contribution Of Activating Transcription Factor 3 To Development Of Acinar-To-Ductal Cell Metaplasia, Jelena Toma

Electronic Thesis and Dissertation Repository

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in North America. The highest risk factor for PDAC is recurrent pancreatitis. While the link between PDAC and pancreatitis is unknown, de-differentiation of acinar cells is common to both diseases. Our lab has shown that Activating Transcription Factor 3 (ATF3), a factor upregulated during pancreatic injury, contributes to the development of acinar-to-ductal cell metaplasia (ADM), a precursor phenotype of PDAC. The goal of this study was to identify how ATF3 contributes to ADM. I hypothesize that ATF3 regulates acinar gene expression promoting ADM. We observed decreased ADM development …

Characterization Of Hemangioma-Initiating Stem Cells, Natalie Montwill

Electronic Thesis and Dissertation Repository

Infantile hemangioma (IH) is the most common vascular tumour of infancy. IH undergoes a unique life cycle consisting of robust endothelial cell proliferation and vessel formation in the proliferating phase, followed by spontaneous regression in the involuting phase. Our laboratory has shown that IH arises from multipotential stem cells termed hemangioma stem cells (HemSCs). However, the phenotype of HemSCs has not been fully elucidated. Here, I examined HemSCs and compared these lesion-derived cells to a panel of normal counterparts. My results show that HemSCs share similar gene expression profiles with human fetal liver-derived stem cells (FLSCs) and postnatal bone marrow …

Mechanisms Underlying Chemotherapy-Induced Vascular Proliferation In Ovarian Cancer, Zeynep Gülsüm Kahramanoğlu

Electronic Thesis and Dissertation Repository

Ovarian cancer is a leading cause of gynecological cancer-related death in Canadian women. Ovarian cancer is managed through surgical cytoreduction and carboplatin-based chemotherapy. Unfortunately, most patients often relapse or have reduced responses to initial chemotherapy. The mechanisms behind carboplatin resistance are poorly understood. In pilot studies, our group has observed vascular proliferation in patient samples following carboplatin treatment. The effectiveness of modulating neovascularization in combination with carboplatin has also been demonstrated in two large Phase 3 trials. In this study, I explore the underlying mechanisms of chemotherapy-induced vascular proliferation and potentially, tumour cell survival. I hypothesize that carboplatin induces angiogenic …

Functional Characteristics Of Four Novel Lone Atrial Fibrillation-Linked Connexin40 Mutants, Mahmoud Noureldin

Electronic Thesis and Dissertation Repository

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. Recently, four novel heterozygous Cx40 mutations, K107R, L223M, Q236H, and I257L were identified in 4 of 310 unrelated AF patients. To study possible alterations associated with these mutants, we studied their localization and function using gap junction (GJ)-deficient model cells. Cell pairs expressing Q236H alone or together with wildtype Cx43 showed a significantly lower coupling conductance. Impaired GJ function and dominant negative action on Cx43 of this mutant are consistent with previous findings on the majority of AF-linked Cx40 mutants. The remaining three novel AF-linked mutants did not show …

Mechanical Properties Of Retrieved Highly Cross-Linked Polyethylene Acetabular Liners In Total Hip Arthroplasty, Gurpreet Singh

Electronic Thesis and Dissertation Repository

Highly cross-linked polyethylene (HXLPE) has replaced the conventional ultra-high-molecular-weight-polyethylene (UHMWPE) as the gold standard bearing surface in total hip arthroplasty (THA) due to superior wear characteristics and survivorship. However, HXLPE has demonstrated poorer mechanical properties, in vivo oxidation, and concerns of rim fractures. The purpose of this project was to study the mechanical properties at the rim of retrieved HXLPE acetabular liners.

We developed a simple technique for measurement of hardness at the rim of irradiated, remelted, HXLPE liners of a specific design. The effect of shelf time on mechanical properties of retrieved liners was determined and showed no correlation …

Risk Factors For Bk Virus Infection After Kidney Transplantation, London, Ontario 2016, Seyed M Hosseini-Moghaddam

Electronic Thesis and Dissertation Repository

Our objective was to determine the risk factors for BK virus infection in renal allograft recipients in the first year after transplantation. In this cohort, we included all patients who received renal allograft at London Health Sciences Centre (LHSC) between 2012 and 2014. We continued post-transplantation follow-up for one year. Of 175 patients (37% female) with median age (range) of 53 (14-82) years, 40 (22.9%) developed BK viremia (median interval:100 days, range: 35-264). Recipient age, recipient gender, hemodialysis (HD) vs peritoneal dialysis (PD), Human Leukocyte Antigens A1, B35 and Cw4 increased the risk of post-transplant BKV infection. However, donor gender, …

Fatigue In Children And Adolescents With Duchenne Muscular Dystrophy, Basmah El-Aloul

Electronic Thesis and Dissertation Repository

Fatigue was recently reported to be the largest predictor of poor health-related quality of life (HRQOL) in children and adolescents with Duchenne muscular dystrophy (DMD). The objectives of this thesis were to describe fatigue from patients’ and parents’ perspectives and to explore associations of patient characteristics with fatigue in children and adolescents with DMD using a multicentre cross-sectional study design. Eligible patients and their parents were identified via the Canadian Neuromuscular Disease Registry and received mailed paper questionnaires. Children and adolescents with DMD experienced greater fatigue compared to healthy controls from published data. Fatigue was a significant issue in children …

Nutrition Screening In The Adult Stroke Population Using The Canadian Nutrition Screening Tool In Comparison With The Subjective Global Assessment, Tess Coutu

Electronic Thesis and Dissertation Repository

Although the Canadian Best Practice Recommendations for Stroke Care recommend all acute stroke patients be screened for malnutrition within 48 hours of admission to hospital using a valid screening tool, none have been validated for use in adult acute stroke patients. The Canadian Nutrition Screening Tool (CNST) tool has been validated within medicine and surgery patients. The purpose of this study is to estimate the level of agreement between the CNST and the Subjective Global Assessment (SGA), a nutrition assessment tool, in a cohort of 58 acute adult stroke patients at the Southwestern Ontario Regional Stroke Centre in London. In …

The Effect Of Insulin Treatment And Exercise Modality On Skeletal Muscle Fiber Size In Streptozotocin-Induced Type 1 Diabetic Rats, John Z. Nickels

Electronic Thesis and Dissertation Repository

Severe Type 1 Diabetes Mellitus (T1DM) is known to have several negative effects on skeletal muscle mass, a condition known as diabetic myopathy. One of these effects is the atrophy of the glycolytic muscle fibers. However, the role of intensity of insulin treatment and exercise modality in attenuating this loss in fiber cross-sectional area (CSA) specifically has yet to be determined. The purpose of this investigation was to determine the effects of 12 weeks of differing intensity of insulin therapy and exercise modality on the CSA of plantaris muscle fibers, identified by myosin heavy chain (MHC) of STZ-induced T1DM rats. …

A National Perspective On Childhood Obesity Medical Education: Do Medical Students In Canada Perceive That They Are Prepared To Treat Children With Obesity?, Dr. Dalia Hasan

Electronic Thesis and Dissertation Repository

The purposes of this survey-based, mixed-methods study were to investigate medical students’ perceptions of: (1) the overall level of medical school training acquired in relation to childhood obesity treatment; (2) the medical school training acquired in relation to specific competencies associated with the treatment of children with obesity and their caregiver(s); and (3) additional training needed. Results showed that of the 507 students who provided complete data, approximately 60% (n = 303) disagreed or strongly disagreed that their medical training related to childhood obesity was adequate. With regard to specific competencies and additional training needed, quantitative and qualitative data revealed …

The Cdk-Resistant Prb-E2f1 Complex Recruits Chromatin-Organizing Proteins To Repetitive Dna Sequences, Charles A. Ishak

Electronic Thesis and Dissertation Repository

This thesis investigates mechanistic links between genome integrity and the recruitment of chromatin organizing proteins to repetitive DNA sequences mediated by the retinoblastoma tumor suppressor protein (pRB). I demonstrate that a CDK-resistant interaction between the pRB C-terminus and the E2F1 coiled-coil marked box domain establishes a scaffold that facilitates recruitment of multiple chromatin-organizing proteins to repetitive sequences across the genome throughout the cell cycle. Specifically, pRB recruits the enhancer-of-zeste-homologue 2 (EZH2) histone methyltransferase to establish repressive facultative heterochromatin at repetitive sequences, and the Condensin II complex to ensure proper DNA replication and mitotic progression. To disrupt the CDK-resistant pRB-E2F1 interaction …

Efficacy Of Selective Laser Trabeculoplasty In Patients With Open-Angle Glaucoma Or Ocular Hypertension: A Systematic Review And Meta-Analysis, Muna Hassan

Electronic Thesis and Dissertation Repository

Purpose: To determine the efficacy of selective laser trabeculoplasty (SLT) in lowering intra-ocular pressure (IOP) levels and reducing the number of medications in patients with open angle glaucoma (OAG) or ocular hypertension (OHT).

Methods: A systematic review was conducted by searching various databases including MEDLINE (Ovid), EMBASE (Ovid), CINAHL, Cochrane Library, Web of Science- Core Collections, BIOSIS Previews, and Scopus. Duplicates were removed and articles were screened using EPPI Reviewer 4.0. A meta-analysis was conducted using STATA 13.0. Weighted mean difference (WMD) was computed and the heterogeneity statistic was assessed using the I². Fixed and random effects models …

Development Of Clinical Prediction Models For Surgery And Complications In Crohn’S Disease, Leonard M. Guizzetti

Electronic Thesis and Dissertation Repository

Background and Objective: Crohn’s disease (CD)-related complications account for a substantial proportion of IBD-related healthcare expenditure. Identifying patients at risk for complications may allow for targeted use of early therapeutic interventions to alter this natural course. The objective of this project was to develop risk prediction models of CD-related surgery and complications.

Methods: Using data from the REACT cluster-randomized clinical trial (N=1898 from 41 community practices), prediction models were developed and internally validated for CD-related surgery and CD-related complications, defined as the first CD-related surgery, hospitalization or complication within 24 months. Performance of each model was assessed in terms of …

Cerebral Lactate Metabolism And Memory: Implications For Alzheimer's Disease, Richard Andrew Harris

Electronic Thesis and Dissertation Repository

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by amyloid plaques that are comprised of aggregated amyloid-beta peptides. These toxic proteins promote mitochondrial dysfunction and neuronal cell death. A shift in metabolism away from oxidative phosphorylation and toward aerobic glycolysis, with the concomitant production of lactate, affords neurons a survival advantage against amyloid-beta toxicity. Recent evidence now suggests that aerobic glycolysis in the brain plays a critical role in supporting synaptic plasticity, learning, and memory. However, the role of aerobic glycolysis and lactate metabolism in AD-mediated cognitive decline is unknown. My objective was to test the hypotheses that aerobic glycolysis …

Investigating E2f Independent Cell Cycle Control And Tumor Suppression By Prb, Michael J. Thwaites

Electronic Thesis and Dissertation Repository

Cellular division is primarily controlled at the G1 to S-phase transition of the cell cycle by the retinoblastoma tumor-suppressor protein (pRB). The ability of pRB to restrict S-phase entry is primarily attributed to the repression of E2F transcription factors required to upregulate cell cycle target genes necessary for cellular division. Interestingly, while pRB is disrupted in the vast majority of human cancers, mutations typically target upstream regulators of pRB leading to inactivation through hyperphosphorylation. The rarity of direct pRB mutations suggests that the regulation of the cell cycle by pRB may involve additional mechanisms outside of E2F repression, as this …

Hsp90 And Its Co-Chaperones Modify Tdp-43 Localization, Aggregation, And Toxicity, Lilian T. Lin

Electronic Thesis and Dissertation Repository

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease associated with protein misfolding and protein aggregation. In particular, the TAR DNA-binding protein (TDP-43) is often found in the pathological inclusions in neurons of ALS patient brains and spinal cords. This phenomenon is known as TDP-43 proteinopathy, the mislocalization of TDP-43 from the cell nucleus and the formation of aggregates in the cytoplasm. Numerous mutations in the gene encoding TDP-43 have also been linked to familial cases of ALS (fALS) and cause TDP-43 proteinopathy. This study attempts to decipher how the molecular chaperone Hsp90 and its co-chaperones, Aha1, Sti1, and Cdc37, modulate …

P23. Elucidation Of The Signaling Pathway Of Mertk, Kyle Taruc

Western Research Forum

Background

Mer Tyrosine Kinase (MERTK) is a receptor which mediates efferocytosis – removal of apoptotic cells by phagocytes such as macrophages. MERTK plays a critical role in homeostasis, with mutations in MERTK associated with the development and progression of atherosclerosis, the buildup of cholesterol-laden plaque in the sub-arterial space. Indeed, one MERTK allele is associated with 66% (heterozygous) to 75% (homozygous) protection from atherosclerosis, while other alleles and SNP’s pre-dispose to atherosclerosis and autoimmunity. Complications resulting from atherosclerosis, including heart attack and stroke, are currently the second leading cause of mortality in Canada. Despite the importance of MERTK in atherosclerosis …

P35. Investigating The Effect Of Maternal Immune Activation On Sensory Filtering, Social Behaviour And Attention, Faraj Haddad

Western Research Forum

Background

Altered brain development is associated with many neuropsychiatric disorders like Autism Spectrum Disorder (ASD) and schizophrenia. Environmental insults can interfere with neurodevelopment, and a prominent example is maternal infection during pregnancy. Epidemiological studies show that children born to mothers who were infected during pregnancy display a higher risk of developing ASD and schizophrenia, and this effect is mainly due to the maternal immune response. Polyinosinic-polycytidilic acid (Poly I:C) is a double stranded RNA molecule that mimics viral markers and elicits an immune response. When injected in pregnant rodents, this model produces offspring that exhibit core symptoms of ASD and …

P30. Optimizing Current Steering In Deep Brain Stimulation For Treating Parkinsonian Axial Motor Symptoms, Daphne Hui

Western Research Forum

Background: The proposed study will investigate deep brain stimulation (DBS), of the subthalamic nucleus (STN) to improve gait dysfunctions in advanced Parkinson’s Disease (PD). DBS requires implantation of electrodes into the brain that contain contacts where current traverses to stimulate neurons. Imprecise electrode implantations are inherent in surgical implantation; thus, contributing to the elusiveness of DBS on gait.

Methods: The proposed investigation will divide current between two contacts to receive 0, 30, 50, 70, or 100% of current, to find the best combination to improve gait. Gait changes associated with fractional combinations will be visually assessed with clinical scales, and …