Medical Specialties Commons^™

Monitoring Intraventricular Hemorrhage In Preterm Infants, Lilian Mn Kebaya

Electronic Thesis and Dissertation Repository

Germinal Matrix-Intraventricular hemorrhage (GMH-IVH) remains a significant cause of adverse neurodevelopmental outcomes in preterm infants. Current management options for GMH-IVH rely on serial 2-dimensional cranial ultrasound (2D cUS) ventricular measurements and clinical signs. A need exists for reliable biomarkers to aid in the early detection of posthemorrhagic ventricular dilatation (PHVD) and cerebral palsy (CP). We incorporated 3-dimensional cranial US (3D cUS) and functional infrared spectroscopy (fNIRS) to monitor ventricle volumes (VV) and spontaneous functional connectivity (sFC) in preterm infants with GMH-IVH. Infants with severe GMH-IVH who underwent cerebrospinal fluid diversion showed larger VV, which correlated with decreased sFC. Our findings …

Development Of An On-Call Assessment Tool For Competency-Based Surgical Training, Eric C. Mitchell

Electronic Thesis and Dissertation Repository

Introduction: A central tenet of competency-based medical education is formative assessment of trainees. There are no assessments examining resident competence on-call, despite this being a significant component of resident training and characterized by less supervision compared to daytime.

Methods: A national survey was conducted to evaluate the state of assessment in Canadian Plastic and Reconstructive Surgery programs. An on-call assessment tool was developed based on a consensus group and was piloted over six months. Validity of the tool was examined through qualitative and quantitative methods.

Results: There were 63 tools completed across ten residents and seven staff physicians. Tool reliability …

Noninvasive Quantification Of Tissue Sodium Concentration In The Kidney Disease Spectrum Using 23na Magnetic Resonance Imaging, Fabio R. Salerno

Electronic Thesis and Dissertation Repository

Chronic kidney disease (CKD), especially when requiring kidney replacement therapy (hemodialysis (HD) and peritoneal dialysis (PD)), is associated with extracellular water expansion with increased total body sodium. Sodium can also be accumulated in tissues independently of extracellular water. Sodium-23 magnetic resonance imaging (²³Na MRI) can quantify the concentration of sodium nuclei in tissues. Applied to the human leg, quantification of tissue sodium concentrations mainly at the skin and muscle level is possible. We hypothesized that increased tissue sodium concentrations exert toxic effects in CKD and dialysis. We aimed to (1) compare tissue sodium concentrations in adults, children and …

Severe Lower Extremity Trauma In Ontario: A Linked Population-Based Analysis, Stephanie M. Kim

Electronic Thesis and Dissertation Repository

Open tibia fractures (OTF) are a management challenge. Admission to a trauma center (TC) and a coordinated approach to bony fixation and soft-tissue reconstruction (STR) have been shown to improve outcomes. The objective of this study was to describe patients who had OTF in Ontario and analyze their outcomes. Linked population data pertaining to patients who had OTF between the years 2009-2020 were examined. Demographic information, admission location, and management course were collected. 4240 patients were found. The mean age was 47, and majority were males. Patients admitted to TC had greater proportion of having Injury Severity Score >15, and …

Fetal Sex Impacts Birth To Placental Weight Ratio And Umbilical Cord Oxygen Values With Implications For Regulatory Mechanisms, Bryan S. Richardson, Akasham Rajagopaul, Barbra De Vrijer, Genevieve Eastabrook, Timothy R.H. Regnault

Obstetrics & Gynaecology Publications

Background: We determined the effect of fetal sex on birth/placental weight and umbilical vein and artery oxygen values with implications for placental efficiency and regulatory mechanisms underlying fetal–placental growth differences. Methods: A hospital database was used to obtain birth/placental weight, cord PO2 and other information on patients delivering between Jan 1, 1990 and Jun 15, 2011 with GA > 34 weeks (N = 69,836). Oxygen saturation was calculated from the cord PO2 and pH data, while fractional O2 extraction was calculated from the oxygen saturation data. The effect of fetal sex on birth/placental weight, cord PO2, O2 saturation, and fractional O2 …

Expression And Localization Of Nrf2/Keap1 Signalling Pathway Genes In Mouse Preimplantation Embryos Exposed To Free Fatty Acids., Grace Dionne, Michele D. Calder, Dean H Betts, Basim Abu Rafea, Andrew J Watson

Obstetrics & Gynaecology Publications

Obese women experience greater incidence of infertility, with reproductive tracts exposing preimplantation embryos to elevated free fatty acids (FFA) such as palmitic acid (PA) and oleic acid (OA). PA treatment impairs mouse preimplantation development in vitro, while OA co-treatment rescues blastocyst development of PA treated embryos. In the present study, we investigated the effects of PA and OA treatment on NRF2/Keap1 localization, and relative antioxidant enzyme (Glutathione peroxidase; Gpx1, Catalase; Cat, Superoxide dismutase; Sod1 and γ-Glutamylcysteine ligase catalytic unit; Gclc) mRNA levels, during in vitro mouse preimplantation embryo development. Female mice were superovulated, mated, and embryos cultured in the presence …

Assessing Cerebral Blood Flow, Oxygenation And Cytochrome C Oxidase Stability In Preterm Infants During The First 3 Days After Birth, Ajay Rajaram, Daniel Milej, Marianne Suwalski, Lilian Kebaya, Matthew Kewin, Lawrence Yip, Sandrine De Ribaupierre, Victor Han, Mamadou Diop, Soume Bhattacharya, Keith St. Lawrence

Paediatrics Publications

A major concern with preterm birth is the risk of neurodevelopmental disability. Poor cerebral circulation leading to periods of hypoxia is believed to play a significant role in the etiology of preterm brain injury, with the first three days of life considered the period when the brain is most vulnerable. This study focused on monitoring cerebral perfusion and metabolism during the first 72 h after birth in preterm infants weighing less than 1500 g. Brain monitoring was performed by combining hyperspectral near-infrared spectroscopy to assess oxygen saturation and the oxidation state of cytochrome c oxidase (oxCCO), with diffuse correlation spectroscopy …

Principles Of Dormancy Evident In High-Grade Serous Ovarian Cancer, Trevor G. Shepherd, Frederick A. Dick

Paediatrics Publications

In cancer, dormancy refers to a clinical state in which microscopic residual disease becomes non-proliferative and is largely refractory to chemotherapy. Dormancy was first described in breast cancer where disease can remain undetected for decades, ultimately leading to relapse and clinical presentation of the original malignancy. A long latency period can be explained by withdrawal from cell proliferation (cellular dormancy), or a balance between proliferation and cell death that retains low levels of residual disease (tumor mass dormancy). Research into cellular dormancy has revealed features that define this state. They include arrest of cell proliferation, altered cellular metabolism, and unique …

Ecological Interchangeability: Supporting Team Adaptive Expertise In Moments Of Disruption, Sayra Cristancho, Emily Field, Lorelei Lingard, Taryn Taylor, Kathryn Hibbert, Graham Thompson, William Hibbert

Obstetrics & Gynaecology Publications

While undesirable, unexpected disruptions offer unique opportunities to enact adaptive expertise. For adaptive expertise to flourish, individuals and teams must embrace both efficiency and adaptation. While some industries do it readily, others continue to struggle with the tension between efficiency and adaptation, particularly when otherwise stable situations are unexpectedly disrupted. For instance, in healthcare settings, the efficiency mandate for strict compliance with scopes of practice can deter teams from using the adaptive strategy of making their members interchangeable. Yet, interchangeability has been hinted as a key capacity of today’ teams that are required to navigate fluid team structures. Because interchangeability …

Comparison Of Hip Navigation System Accuracy In Direct Anterior Approach, Jeremy Loh

Electronic Thesis and Dissertation Repository

Introduction

Malposition of the acetabular component has been thought to have an influence on increasing increase the risk instability, impingement, and ultimately revision surgery. Hip navigation technology has been developed to provide the surgeon with real time intraoperative metrics to make critical decisions in implant placement. The goal of this study was to compare the accuracy of acetabular component positioning in direct anterior approach hip replacements using conventional fluoroscopy only technique, fluoroscopic image dependent navigation, and imageless navigation.

Methods

A retrospective data collection and prospective analysis was conducted for this study. After sample size calculations, fifty patients were collected for …

A Long-Term Follow-Up Of The Stability Study: Multicenter Rct Comparing Anterior Cruciate Ligament Reconstruction With And Without Lateral Extra-Articular Tenodesis In Individuals At High Risk Of Graft Failure, Katelyn M. Inch

Electronic Thesis and Dissertation Repository

One hundred and ninety-six patients at the Fowler Kennedy Sport Medicine Clinic (FKSMC) undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) were randomized as part of the multi-center STABILITY study to receive either an isolated ACLR or ACLR with a lateral extra-articular tenodesis (LET). The STABILITY study followed these patients up to two years postoperative, and a long-term follow-up protocol was initiated afterwards. Eighty-two patients from this center were seen at three, five and seven years postoperative as part of a long-term follow-up. Our primary outcome was a composite outcome of instability and graft failure. Secondary outcomes included patient-reported outcome measures …

Exploration Of The Pathophysiological Mechanisms Underlying Hemodialysis Associated Cardiac Ischemic Injury, Lisa Yun Jeong Hur

Electronic Thesis and Dissertation Repository

Hemodialysis (HD) provides life-saving treatment in individuals with kidney failure. However, HD is associated with poor quality of life and extremely high mortality rates mainly caused by cardiovascular disease due to heart failure and sudden cardiac death. Standard pharmacological treatment developed within the non-kidney disease community are largely ineffective in HD patients because of the difference in pathophysiology of cardiovascular mortality. HD treatment causes hypotension and recurrent ischemic injury to multiple vascular beds including the heart, leading to heart failure. These injuries can be abrogated by improving the patient’s tolerability of the treatment. To apply interventions that may improve hemodynamic …

The Clinical Value Of Oculomotor Assessments Across The Continuum Of Concussion, Dillon Richards

Electronic Thesis and Dissertation Repository

Concussions are complex conditions that are difficult to manage medically. Variations in symptom presentation, intricate neurophysiological processes, and the availability of a variety of possible assessment tools may contribute to this complexity. Clinicians must use a broad approach, employing both subjective symptom assessment and objective assessments to confirm a diagnosis and/or monitor progression and recovery. Oculomotor function after concussion may be an important indicator of injury, given the interconnectedness of oculomotor function, vestibulo-ocular and visual systems, and even cognition. Oculomotor function may be assessed objectively or indirectly using patient-reported symptom checklists as part of subjective assessments. One way of objectively …

Total Hip Arthroplasty In Young Patients, Aaron G. Chen

Electronic Thesis and Dissertation Repository

Total hip arthroplasty (THA) is the gold standard in treatment of hip arthritis yet is often avoided in young patients due to concerns of inferior survivorship. We aim to explore the role of THA in young patients and assess whether these historical concerns are valid in contemporary THA by presenting the results of: (1) a systematic review and meta-analysis of the current literature, (2) a retrospective database review, and (3) a retrospective population-based study. We found excellent long-term survivorship with modern THA in young patients, demonstrating greater than 90% revision-free survival up to 15 years. Factors that may increase risk …

Decompression Vs. Decompression And Fusion In Cauda Equina Syndrome Secondary To Massive Lumbar Disc Herniation, Ruheksh Raj

Electronic Thesis and Dissertation Repository

Posterior spinal surgery through either a decompression or additional fusion procedure is the widely accepted standard of care for patients presenting with cauda equina syndrome (CES) secondary to massive disc herniation. A plethora of literature has been published regarding post- surgical outcome, particularly in regards to improvement of lower sacral nerve symptoms in relation to timing of surgery. There is a paucity of data with regards to long term clinical outcomes in patients between the decompression and decompression and fusion groups. We initially hypothesized was that there would be no longer term clinical differences in outcome between the two groups, …

Facing Hierarchy: A Qualitative Study Of Residents' Experiences In An Obstetrical Simulation Scenario, Adam B Garber, Glenn Posner, Taylor Roebotham, M Dylan Bould, Taryn Taylor

Obstetrics & Gynaecology Publications

BACKGROUND: Residents in surgical specialties face a steep hierarchy when managing medical crises. Hierarchy can negatively impact patient safety when team members are reluctant to speak up. Yet, simulation has scarcely been previously utilized to qualitatively explore the way residents in surgical specialities navigate this challenge. The study aimed to explore the experiences of residents in one surgical specialty, obstetrics and gynecology (Ob/Gyn), when challenging hierarchy, with the goal of informing future interventions to optimize resident learning and patient safety.

METHODS: Eight 3rd- and 4th-year Ob/Gyn residents participated in a simulation scenario in which their supervising physician made an erroneous …

Multimorbidity And Cognition Among Canadian Older Adults: A Three-Decade Perspective, Juan Camilo Vargas Gonzalez

Electronic Thesis and Dissertation Repository

Background: Scarce information exists about whether the relationship between multimorbidity and cognitive decline has changed over the past decades.

Objectives: 1) To summarize knowledge about the association of multimorbidity and cognitive decline by performing a systematic review. 2) To estimate the association between multimorbidity in two cohorts selected three decades apart. 3)To identify which multimorbidity combinations have the strongest associations with cognitive decline 4) To identify protective factors that reduce the risk of cognitive decline in the presence of multimorbidity.

Methods: We performed a systematic review following the PRISMA statement. We then addressed objectives 2-4 by analyzing data from two …

Radiation Exposure Determination In A Secure, Cloud-Based Online Environment, Ben C. Shirley, Eliseos J. Mucaki, Peter Rogan

Biochemistry Publications

Rapid sample processing and interpretation of estimated exposures will be critical for triaging exposed individuals after a major radiation incident. The dicentric chromosome (DC) assay assesses absorbed radiation using metaphase cells from blood. The Automated Dicentric Chromosome Identifier and Dose Estimator System (ADCI) identifies DCs and determines radiation doses. This study aimed to broaden accessibility and speed of this system, while protecting data and software integrity. ADCI Online is a secure web-streaming platform accessible worldwide from local servers. Cloud-based systems containing data and software are separated until they are linked for radiation exposure estimation. Dose estimates are identical to ADCI …

Technical Adaptations For Cardiac Sodium Mri, Taylor L. Marcus

Electronic Thesis and Dissertation Repository

Cardiac sodium (Na⁺) MRI has the potential to unveil relationships between chronic kidney disease (CKD) and cardiovascular disease (CVD). Unfortunately, this modality requires many technical adaptations before it’s possible to extract and compare image data between individuals. This study investigated whether cardiac electrocardiogram (ECG) gating could improve image quality, and whether a uniform phantom could increase signal uniformity if a surface coil is used to acquire the image. Healthy participants were imaged with a custom-built surface coil and 3.0-T MR system. Cardiac gated images presented with a decreased signal-to-noise ratio (SNR), but intensity correction significantly increased image signal …

Highlighting The Mechanistic Relationship Between Perinatal Depression And Preeclampsia: A Scoping Review, Mei Yuan, Samantha Bedell, Barbra De Vrijer, Genevieve Eastabrook, Jefferson C. Frisbee, Stephanie J. Frisbee

Obstetrics & Gynaecology Publications

Background: Although there is scientific literature supporting an association between depression and preeclampsia (PE), little is known about the underlying mechanistic pathways that may explain these observed associations. Thus, this study aimed to outline the relationship between depression and PE, and to highlight the underlying cardiovascular and metabolic risk factors that are common to both. Methods: A scoping review of the literature was conducted in Medline, Scopus, and Web of Science. Results: From 706 articles initially identified, 23 articles met the inclusion criteria and were included in this review. Although some studies reported a positive association between PE and postpartum …

Multi-Scale Computational Modeling Of Coronary Blood Flow: Application To Fractional Flow Reserve., Jermiah Joseph

Electronic Thesis and Dissertation Repository

Introduction. Fractional flow reserve (FFR) is presently an invasive coronary clinical index. Non-invasive CT imaging combined with computational coronary flow modelling may reduce the patient’s burden of undergoing invasive testing.

Research statement. The ability to obtain information of the hemodynamic significance of detected lesions would streamline decision making in escalation to invasive angiography.

Methods. A reduced order (lumped parameter) model of the coronary vasculature was further developed. The model was used in the assessment of the roles of structure and function on the FFR. Sophisticated methods were used to elicit numerical

solutions. Further, CT imaging (n = …

Determination Of The Protective Capacity Of Hand Wraps In Combat Athletes Using Force Analysis, Eva M. Gusnowski

Electronic Thesis and Dissertation Repository

Upper extremity injuries are common in combat athletes, and are highest in the hand/wrist. Although protective hand gear is used, there is a paucity of research investigating its effectiveness. This study addressed this knowledge gap by measuring the level of force transmitted to the hand during striking using two types of hand wraps. This prospective cross over study included six combat athletes. A load cell was placed over the proximal phalanges/metacarpophalangeal joints and was used to measure sustained peak force during striking while covered with either standard linear or gel-reinforced hand wraps and boxing gloves. The gel reinforced wraps consistently …

Role Of Decorin At The Fetal-Maternal Interface, Chidambra D. Halari

Electronic Thesis and Dissertation Repository

The human placenta is an invasive tumor-like structure, this invasion being physiological. A subset of placental trophoblast called extra-villous trophoblast invades the uterine decidua and remodels uterine arteries into low-resistance, high-flow tubes to permit adequate flow of maternal blood to nourish the fetus. A poor extra-villous trophoblast invasion and uterine arterial remodeling can lead to fetal growth restriction and a serious pregnancy-associated maternal disease preeclampsia. Decorin, a leucine-rich proteoglycan produced by uterine decidual cells restrains multiple trophoblast functions: self-renewal and differentiation of trophoblast stem cells, migration, invasion, proliferation and endovascular differentiation. Additionally, decidual overproduction of decorin was associated with preeclampsia, …

Biomechanical Characterization Of Semi-Rigid Constructs And The Potential Effect On Proximal Junctional Kyphosis In The Thoracic Spine, Chloe Cadieux

Electronic Thesis and Dissertation Repository

Long spinal fusions are the mainstay of treatment in adult spinal deformity; however, proximal junctional kyphosis (PJK) is a common and potentially catastrophic complication that can occur following this procedure. It has been hypothesized that using semi-rigid constructs at the superior aspect of the instrumentation may decrease this complication. The objective of this thesis was to determine if there is a biomechanical advantage between various semi-rigid constructs utilized in long spinal fusions to help decrease the risk of PJK. Nine human cadaveric spines (T1 – T12) instrumented with the standard all-pedicle-screw construct (APS) were compared to various semi-rigid constructs including …

The Molecular Landscape Of Early-Stage Breast Cancer With Lymph Node Metastasis, Farhad Ghasemi

Electronic Thesis and Dissertation Repository

Axillary lymph nodes (ALNs) are the primary site of metastasis in breast cancer, and their involvement has implications in disease staging, prognostication, and treatment decisions. A non-invasive modality of assessing the risk of ALN metastasis can improve care in patients with early-stage breast cancer by omitting the morbidity and costs associated with axillary surgery.

This thesis explores the molecular landscape of early-stage breast cancers with ALN metastasis and shows the potential of tumour molecular signatures in predicting ALN involvement. After a systematic review of the literature, we use data from The Cancer Genome Atlas (TCGA) to develop molecular signatures correlated …

Reporting Standards For Machine Learning Research In Type 2 Diabetes, Grace Kang

Undergraduate Student Research Internships Conference

In this project, three people scored 90 papers on machine learning predictive models for type 2 diabetes to assess their adherence to TRIPOD, MI-CLAIM, and DOME reporting guidelines.

Wellness Study: Functional Visual Outcomes In Eye Disease Patients Following The Covid-19 Pandemic, Andrew Maher

Undergraduate Student Research Internships Conference

The COVID-19 pandemic has caused delays in health services and medical appointments, affecting approximately one in three Canadian adults. Elderly eye disease patients experienced delays in treatment for eye conditions including cataracts, glaucoma, and retinal diseases. The impact of these delays on functional visual outcomes and general health rating of elderly patients is not well understood. As part of the Wellness Study, we aimed to investigate the pandemic-related impacts on functional vision and general health rating in an elderly eye patient population in London, Ontario.

A Collaborative Approach To Caring For Refugees In The Covid-19 Pandemic, Sara Mojdehi

Undergraduate Student Research Internships Conference

With higher cases rates, it is clear that newcomer and refugee populations in Ontario have been disproportionately affected by the COVID-19 pandemic. These vulnerable populations generally work in settings that increase their risk of infection and do not offer sick leave (ICES, 2021). In addition, overcrowded and multigenerational housing make it difficult for these individuals to adhere to self-isolation guidelines. Language and cultural barriers among refugee populations have also limited their access to information about the virus, making it challenging to follow public health measures (ICES, 2021).

The increased likelihood of an outbreak in these communities manifested itself in London, …

Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson

Electronic Thesis and Dissertation Repository

The cerebral cortex contains myriad cortical areas that differ in structure, function, and connectivity. Current methods of delineating cortical structures and their subregions are insufficient for in vivo applications, either being highly invasive or requiring a detailed knowledge of a region’s tuning properties. To address this, we seek to establish a structural biomarker capable of delineating the cortex that possesses a non-invasive correlate. We explore myelin as a potential candidate by evaluating its efficacy in parcellating the feline auditory cortex through the generation of depthwise myelin density profiles for each of the 13 auditory cortical subregions. Our analyses revealed significant …

Feasibility And Clinical Value Of 3-Dimensional Myocardial Deformation Analysis By Computed Tomography In Transcatheter Aortic Valve Replacement Patients, Mohamad Rabbani

Electronic Thesis and Dissertation Repository

Purpose: Multi-phase computed tomography angiography (CTA) for the pre-procedural planning of TAVR presents a unique opportunity to assess 3D myocardial biomechanics. This study aimed to assess the feasibility and predictive utility of 3D myocardial deformation analysis (3D-MDA) based principal strain to predict heart failure or death following TAVR using pre-procedural, multi-phase computed tomography angiography (CTA) datasets.

Methods: Two hundred and five patients undergoing pre-TAVR multi-phase gated CTA followed by successful TAVR were retrospectively identified. Whole heart 3D mesh chamber models were generated followed by 3D-MDA of the left ventricle (LV) to determine global LV minimum principal strain (minPS) for endocardial, …