Medicine and Health Sciences Commons^™

Peptide-Mediated Targeting Of Angiogenesis For Molecular Imaging And Treatment Of Cancer, Choi-Fong Cho

Electronic Thesis and Dissertation Repository

The development of screening approaches to identify novel affinity ligands has paved the way for a new generation of molecular targeted nanomedicines. To identify novel targeting ligands, several studies have demonstrated the advantages in screening one-bead-one-compound (OBOC) libraries. Conventional methods typically bias the display of the target protein to ligands during the screening process. We have developed an unbiased multiplex ‘beads on a bead’ strategy to isolate, characterize, and validate high affinity ligands from OBOC libraries. In addition, due to the advantages associated with screening OBOC libraries directly against living cells, we sought to combine cell-based screen methods with automated …

The Role Of Aldhhicd44+ Cells In Breast Cancer Metastasis And Therapy Resistance, Alysha K. Croker

Electronic Thesis and Dissertation Repository

Breast cancer is a leading cause of death in women, due primarily to ineffective treatment of metastatic disease. Despite being a lethal process, metastasis is surprisingly inefficient, with less than 0.5% of cancer cells able to successfully navigate the metastatic cascade, indicating that only a small proportion of cancer cells possess the necessary characteristics to establish metastases. Cancer stem cells (CSCs) have recently been identified in leukemia and solid tumors; however, the role of CSCs in breast cancer metastasis and therapy resistance remains poorly understood. Sub-populations of cells demonstrating stem-cell like characteristics (high expression of CSC markers and/or high ALDH …

The Role Of Ca2+/Calmodulin Dependent Protein Kinase Ii Alpha In Group 1 Metabotropic Glutamate Receptor Endocytosis And Signalling, Stephanie C. Kulhawy

Electronic Thesis and Dissertation Repository

Group 1 metabotropic glutamate receptors (mGluR1 and mGluR5) are G-protein coupled receptors (GPCRs) activated by glutamate. mGluR1/5 couples to Gα_q/11 and releases Ca²⁺ from the endoplasmic reticulum. Ca²⁺/calmodulin-dependent protein kinase II alpha (CaMKIIα) can be activated by Gα_q/11-mediated Ca²⁺ release through binding of Ca²⁺/calmodulin. Results from a proteomic screen identified CaMKII as a novel mGluR-interacting protein. Therefore, we hypothesized that CaMKIIα associates with group 1 mGluRs and this association alters mGluR1/5 signalling and internalization. Firstly, we demonstrated the novel association between CaMKIIα and mGluR1/5 by co-immunoprecipitation of transiently transfected proteins in …

Immunohistochemical Studies Of Expression And Correlation Of Osteopontin, Cd44, And Integrin Αvβ3 In Selected Benign And Malignant Salivary Gland Tumours, Tommy Fok

Electronic Thesis and Dissertation Repository

Osteopontin (OPN) is a phosphorylated acidic glycoprotein that has been shown to play a vital role in tumourigenesis and metastases. The objective of this study was to determine the expression of OPN and its receptors (CD44 and integrin α_vβ₃) in several salivary gland cancers, and assess its clinical correlations.

Immunohistochemical techniques were used to semi-quantify the level of OPN expression and its receptors in normal salivary glands and different types of salivary gland tumour.

Our results show that in tumours of salivary gland origin, higher levels of OPN were detected in tumours which were malignant compared …

Roles Of Pgc-1Α/Ppars Pathway In Regulating Insulin Sensitivity In Mouse Skeletal Muscle Cells Under Prolonged Hypoxia, Yunyan Zhang

Electronic Thesis and Dissertation Repository

Using the C₂C₁₂ mouse myoblast cell line, I investigated how prolonged hypoxia affected components of the insulin signalling and FAO/PGC-1α/PPARs pathways, as they might impact insulin sensitivity in skeletal muscle cells.

Hypoxia resulted in lower p-Akt (Thr 308) and higher total cellular GLUT4 protein levels after 7 days of differentiation. This coincided with higher triglyceride content and alterations of the FAO/PGC-1α/PPARs components, both of which could contribute to the changes observed in the components of the insulin signalling pathway. Specifically, cells differentiating in 1% O₂ had lower SIRT1, PPAR- α, FATP4 and MCAD mRNA; accompanied by …

The Role Of Non-Canonical Wnt/Planar Cell Polarity Signalling In Breast Cancer Progression, Connor D. Macmillan

Electronic Thesis and Dissertation Repository

The role of planar cell polarity (PCP) signalling in breast cancer is unclear, as evidence shows that activation of this pathway with WNT5A can either promote or inhibit progression. Using the 21T cells, which represent distinct stages of breast cancer progression when grown in a mouse xenograft model (21PT, atypical ductal hyperplasia; 21NT ductal carcinoma in situ; 21MT-1, invasive mammary carcinoma), I hypothesized that WNT5A will promote progression only when VANGL1, another component of PCP signalling, is elevated.

Each 21T cell line showed distinct stage-specific morphologies when grown in a Matrigel “on-top” assay. WNT5A overexpression promoted progression to an invasive …

Regulation Of Nk Cell-Mediated Tubular Epithelial Cell Death And Kidney Ischemia-Reperfusion Injury By The Nkr-P1b Receptor And Clr-B, James Yip

Electronic Thesis and Dissertation Repository

Renal ischemia-reperfusion injury (IRI) occurs following reduced renal blood flow and is a major cause of acute injury in both native and transplanted kidneys. We have previously demonstrated that NK cells can mediate tubular cell death and kidney IRI. Natural killer receptor-protein 1B (NKR-P1B) has been shown to interact with C-type lectin-related protein B (Clr-b), resulting in the suppression of NK cell-mediated cytotoxicity.

Clr-b mRNA and protein expression in the kidney were up-regulated after renal IRI. Similar upregulation of Clr-b expression was seen in cytokine-challenged primary-cultured tubular epithelial cells (TEC). Furthermore, NK cytotoxicity assays demonstrated enhanced necrotic death in TEC …

Gender Does Not Influence The Relationship Between Posterior Cruciate Ligament Design And Patient-Reported Outcomes In Patients Receiving Primary Unilateral Total Knee Arthroplasty, Ryan Milan

Electronic Thesis and Dissertation Repository

The effect of the interaction between gender and posterior cruciate ligament (PCL) prosthesis design on patient-reported outcomes is an understudied area of research. We evaluated 1613 patients, from the Ontario Joint Replacement Registry (2001-2006), who underwent primary total knee replacement. This study investigated the impact of the gender-PCL design interaction on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) change scores and patient satisfaction, by performing linear regression analysis, using full-adjusted models that also included the gender-PCL prosthesis design interaction variable. PCL prosthesis design did not affect WOMAC change scores or satisfaction (p>0.05). Moreover, Gender did not influence either …

Septohippocampal Gabaergic Neurons Mediate The Altered Behaviors Induced By N-Methyl-D-Aspartate Receptor Antagonists., Jingyi Ma, Siew Kian Tai, L Stan Leung

Physiology and Pharmacology Publications

We hypothesize that selective lesion of the septohippocampal GABAergic neurons suppresses the altered behaviors induced by an N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine or MK-801. In addition, we hypothesize that septohippocampal GABAergic neurons generate an atropine-resistant theta rhythm that coexists with an atropine-sensitive theta rhythm in the hippocampus. Infusion of orexin-saporin (ore-SAP) into the medial septal area decreased parvalbumin-immunoreactive (GABAergic) neurons by ~80%, without significantly affecting choline-acetyltransferase-immunoreactive (cholinergic) neurons. The theta rhythm during walking, or the immobility-associated theta induced by pilocarpine, was not different between ore-SAP and sham-lesion rats. Walking theta was, however, more disrupted by atropine sulfate in ore-SAP than …

Evaluation Of The Utility Of Decomposition-Enhanced Spike-Triggered Averaging Motor Unit Number Estimation As An Outcome Measure For The Study Of Amyotrophic Lateral Sclerosis, Colleen T. Ives

Electronic Thesis and Dissertation Repository

OBJECTIVES: The objectives of this thesis were to review the use of outcome measures systematically across amyotrophic lateral sclerosis (ALS) clinical trials, and evaluate the utility of decomposition-enhanced spike-triggered averaging (DE-STA) motor unit number estimation (MUNE) as an outcome measure, with a particular focus on its application to the upper trapezius (UT).

METHODS: First, a systematic review quantified the frequency of use of outcome measures in ALS randomized controlled trials (Chapter 2). Next, the intra- and inter-rater reliability of DE-STA MUNE was evaluated in the UT of control subjects (Chapter 3), followed by the intra-rater reliability of the technique in …

Trpm2 In The Central Nervous System: Physiological Role And Critical Regulatory Pathways, Jillian C. Belrose

Electronic Thesis and Dissertation Repository

TRPM2 is a non-selective cation channel which is permeable to calcium. Although expression is highest in the brain, the physiological role for TRPM2 in neurons was unknown. Furthermore, our understanding of the pathways regulating TRPM2 channel function required further investigation. In this thesis, we identified that TRPM2 is required for NMDAR-dependent long-term depression (LTD). No change in NMDAR expression or function was observed following genetic deletion of TRPM2. Instead, the loss of NMDAR-LTD in TRPM2 knockout mice results from diminished GSK-3β activation. We next examined whether age in vitro could facilitate TRPM2 currents. We demonstrate that diminished glutathione with age …

Sexual Reward And Depression, Andrea R. Di Sebastiano

Electronic Thesis and Dissertation Repository

Sexual behavior in male rats is a complex rewarding behavior and many neurotransmitters and neuropeptides play an important role in mediation of sexual performance, motivation and reward. The hypothalamic neuropeptide orexin has been shown play a key role in reward associated with food and drugs of abuse, but the role of this neuropeptide in control of sexual performance, motivation and reward is currently unclear. First, it was shown that orexin neurons in the hypothalamus are activated during sexual performance and reward. Next, using cell specific lesions of orexin neurons it was demonstrated that orexin is involved in arousal and anxiety, …

Evidence Of Adult Lung Growth In Humans., Miranda Kirby, David G Mccormack, Grace Parraga

Medical Biophysics Publications

A 33-year-old woman underwent a right-sided pneumonectomy in 1995 for treatment of a lung adenocarcinoma. As expected, there was an abrupt decrease in her vital capacity, but unexpectedly, it increased during the subsequent 15 years. Serial computed tomographic (CT) scans showed progressive enlargement of the remaining left lung and an increase in tissue density. Magnetic resonance imaging (MRI) with the use of hyperpolarized helium-3 gas showed overall acinar-airway dimensions that were consistent with an increase in the alveolar number rather than the enlargement of existing alveoli, but the alveoli in the growing lung were shallower than in normal lungs. This …

Exploration Of Three-Dimensional Morphometrics Of The Hip Joint And Reconstructive Technologies, Charys M. Martin

Electronic Thesis and Dissertation Repository

This dissertation is an exploration of three-dimensional (3D) anatomy using the hip joint as the model of study. Very few studies have taken advantage of 3D modeling to assess the features of commercially available software, or to assess the validity and reliability of 3D morphometrics. This dissertation compared three reconstructive software programs to survey user appreciation concerning how 3D anatomical reconstructive software can be utilized and then established the advantages and limitations of 3D measurements in the hip joint. Three main studies are presented: the first, a comparison of three widely available 3D reconstructive software programs, Amira, OsiriX, and Mimics. …

Algorithmic Decomposition Of Shuffle On Words, Franziska Biegler, Mark Daley, Ian Mcquillan

Brain and Mind Institute Researchers' Publications

We investigate shuffle-decomposability into two words. We give an algorithm which takes as input a DFA M (under certain conditions) and determines the unique candidate decomposition into words u and v such that L(M) = u v ifM is shuffle decomposable, in time O(|u| + |v|). Even though this algorithm does not determine whether or not the DFA is shuffle decomposable, the sublinear time complexity of only determining the two words under the assumption of decomposability is surprising given the complexity of shuffle, and demonstrates an interesting property of the operation. We also show that for given words u and …

Expanding The Basic Science Debate: The Role Of Physics Knowledge In Interpreting Clinical Findings., Mark Goldszmidt, John Paul Minda, Sarah L Devantier, Aimee L Skye, Nicole N Woods

Brain and Mind Institute Researchers' Publications

Current research suggests a role for biomedical knowledge in learning and retaining concepts related to medical diagnosis. However, learning may be influenced by other, non-biomedical knowledge. We explored this idea using an experimental design and examined the effects of causal knowledge on the learning, retention, and interpretation of medical information. Participants studied a handout about several respiratory disorders and how to interpret respiratory exam findings. The control group received the information in standard "textbook" format and the experimental group was presented with the same information as well as a causal explanation about how sound travels through lungs in both the …

Frequency-Dependent Conduction Block In Demyelinating Focal Neuropathies, Brad V. Watson

Electronic Thesis and Dissertation Repository

It is the objective of this thesis to demonstrate conduction block across regions of focal demyelination by utilizing a conventional electrophysiological technique used frequently in the diagnosis of peripheral nerve disease. Specifically, patients with moderate to severe carpal tunnel syndrome (CTS), but, with no evidence of conduction block via conventional motor nerve conduction study techniques, were assessed in the initial studies of this thesis for evidence of frequency-dependent conduction block (FDB) by way of high-frequency nerve stimulation (HFNS) applied across the region of entrapment. The final studies examined whether FDB could be demonstrated along the median motor fibers in mild …

Hyperpolarized 3he And 129xe Mr Imaging In Healthy Volunteers And Patients With Chronic Obstructive Pulmonary Disease, Miranda Kirby, Sarah Svenningsen, Amir Owrangi, Andrew Wheatley, Adam Farag, Alexei Ouriadov, Giles E Santyr, Roya Etemad-Rezai, Harvey O Coxson, David G Mccormack, Grace Parraga

Medical Biophysics Publications

PURPOSE: To quantitatively compare hyperpolarized helium 3 (3He) and xenon 129 (129Xe) magnetic resonance (MR) images obtained within 5 minutes in healthy volunteers and patients with chronic obstructive pulmonary disease (COPD) and to evaluate the correlations between 3He and 129Xe MR imaging measurements and those from spirometry and plethysmography.

MATERIALS AND METHODS: This study was approved by an ethics board and compliant with HIPAA. Written informed consent was obtained from all subjects. Eight healthy volunteers and 10 patients with COPD underwent MR imaging, spirometry, and plethysmography. Ventilation defect percentages (VDPs) at 3He and 129Xe imaging were obtained by using semiautomated …

The Cross Talk Between Trkb And Nmda Receptors Through Rasgrf1, Asghar Talebian

Electronic Thesis and Dissertation Repository

Introduction: Brain-derived neurotrophic factor (BDNF) facilitates neuronal differentiation by activation of the TrkB receptor-tyrosine-kinase. BDNF/TrkB also modulates the activity of the excitatory N-methyl-D-aspartate neurotransmitter receptor (NMDAR), thereby also regulating neural plasticity and LTP/LTD, two forms of synaptic plasticity that contribute to the storage of information inside the brain. How TrkB cross-talks to modulate NMDAR function is not known, although our working model involves the RasGrf1 signaling molecule, a nucleotide exchange factor for Ras/Rac-GTPases, which interacts with both receptors. In response to TrkB activation, Ras-Grf1 is tyrosine phosphorylated and mediates neurite outgrowth in PC12 cells. RasGrf1 also binds constitutively to …

A Pilot Trial Comparing The Effects Of Onabotulinumtoxina And Standard Oxybutynin Therapy As First Line Treatment For The Poorly Compliant Pediatric Neurogenic Bladder, Sumit Dave

Electronic Thesis and Dissertation Repository

Research question

Is it feasible to conduct a phase III RCT to compare OnabotulinumtoxinA injections to oxybutynin as primary therapy in pediatric neurogenic bladder?

Methods

Patients on a stable oxybutynin regimen were recruited for a pilot RCT and underwent randomization to either OnabotulinumtoxinA or continuation of oxybutynin. Primary outcomes included an a priori defined feasibility and acceptability assessment. Secondary outcomes included continence, urodynamic parameters, side effects and QOL.

Results

The study enrolled 8 subjects in the OnabotulinumtoxinA group and 6 in the oxybutynin group. The recruitment rate was 75 % and the dropout rate was 6.6 %. There were 2 …

Psychophysical And Neural Evidence For Emotion-Enhanced Perceptual Vividness, Rebecca M. Todd, Deborah Talmi, Taylor W. Schmitz, Josh Susskind, Adam K. Anderson

Brain and Mind Institute Researchers' Publications

Highly emotional events are associated with vivid "flashbulb" memories. Here we examine whether the flashbulb metaphor characterizes a previously unknown emotion-enhanced vividness (EEV) during initial perceptual experience. Using a magnitude estimation procedure, human observers estimated the relative magnitude of visual noise overlaid on scenes. After controlling for computational metrics of objective visual salience, emotional salience was associated with decreased noise, or heightened perceptual vividness, demonstrating EEV, which predicted later memory vividness. Event-related potentials revealed a posterior P2 component at ~200 ms that was associated with both increased emotional salience and decreased objective noise levels, consistent with EEV. Blood oxygenation level-dependent …

What Can Computed Tomography And Magnetic Resonance Imaging Tell Us About Ventilation?, Brett A Simon, David W Kaczka, Alexander A Bankier, Grace Parraga

Medical Biophysics Publications

This review provides a summary of pulmonary functional imaging approaches for determining pulmonary ventilation, with a specific focus on multi-detector x-ray computed tomography and magnetic resonance imaging (MRI). We provide the important functional definitions of pulmonary ventilation typically used in medicine and physiology and discuss the fact that some of the imaging literature describes gas distribution abnormalities in pulmonary disease that may or may not be related to the physiological definition or clinical interpretation of ventilation. We also review the current state-of-the-field in terms of the key physiological questions yet unanswered related to ventilation and gas distribution in lung disease. …

Human Cerebrovascular Endothelial Cell Responses In Severe Sepsis, Christopher J. Blom

Electronic Thesis and Dissertation Repository

Sepsis-associated encephalopathy (SAE) is an independent predictor of mortality in severe sepsis patients. Mechanisms of SAE are poorly characterized. Pro-inflammatory mediators are up-regulated in blood plasma of severe sepsis patients and may lead to activation/dysfunction of cerebrovascular endothelial cells (CMEC) of the blood-brain barrier (BBB) – potentially contributing to brain dysfunction. The objective of the present study was to determine the effects/mechanisms of both human severe sepsis blood plasma (hSSP; 20% v/v) and a mixture of 8 cytokines/chemokines that mimicked physiological concentrations of cytokines/chemokines in hSSP (cytomix; SSCM) on human-derived CMEC (hCMEC/D3) activation/dysfunction

in vitro. hSSP-stimulation up-regulated hCMEC/D3 pro-adhesive …

Transforming Growth Factor Beta Receptor Partitioning: Molecular Mechanisms And Functional Consequences, Sarah E.A. Mclean

Electronic Thesis and Dissertation Repository

The transforming growth factor beta (TGFbeta) pathway has been conserved throughout evolution and plays important roles in tissue homeostasis. Dysregulation of the TGFbeta pathway has been implicated in a number of disorders, including cancer, fibrosis, and vascular conditions. The signalling potential of the TGFbeta pathway is regulated by the route of internalization of its cell-surface receptors: Receptors internalized by clathrin-mediated endocytosis propagate signal transduction while those internalized by membrane rafts are targeted for degradation. Given the importance of trafficking of the TGFbeta receptors to signal propagation, this thesis focuses on evaluating proteins which direct TGFb receptor internalization and trafficking. Initial …

Perceptual Fluency Can Be Used As A Cue For Categorization Decisions., Sarah J Miles, John Paul Minda

Brain and Mind Institute Researchers' Publications

Learning in the prototype distortion task is thought to involve perceptual learning in which category members experience an enhanced visual response (Ashby & Maddox. Annual Review of Psychology, 56, 149-178, 2005). This response likely leads to more-efficient processing, which in turn may result in a feeling of perceptual fluency for category members. We examined the perceptual-fluency hypothesis by manipulating fluency independently from category membership. We predicted that when perceptual fluency was induced using subliminal priming, this fluency would be misattributed to category membership and would affect categorization decisions. In a prototype distortion task, the participants were more likely to judge …

Gonadotropin-Releasing Hormone Plasticity: A Comparative Perspective., T J Stevenson, T P Hahn, S A Macdougall-Shackleton, G F Ball

Brain and Mind Institute Researchers' Publications

Gonadotropin-releasing hormone 1 (GnRH1) is a key regulator of the reproductive neuroendocrine system in vertebrates. Recent developments have suggested that GnRH1 neurons exhibit far greater plasticity at the cellular and molecular levels than previously thought. Furthermore, there is growing evidence that sub-populations of GnRH1 neurons in the preoptic area are highly responsive to specific environmental and hormonal conditions. In this paper we discuss findings that reveal large variation in GnRH1 mRNA and protein expression that are regulated by social cues, photoperiod, and hormonal feedback. We draw upon studies using histochemistry and immediate early genes (e.g., c-FOS/ZENK) to illustrate that specific …

Differential Effects Of Macaque Dorsolateral Prefrontal Deactivations During Uncued And Cued Role Conditions, Sabeeha Hussein

Electronic Thesis and Dissertation Repository

Cognitive control enables us to guide our behaviour in an appropriate, context-dependent manner. This behavioral flexibility is probed by task-switching paradigms, which require working memory to maintain relevant rules and flexibility to switch between rules. The dorsolateral prefrontal cortex (DLPFC) has been implicated in rule maintenance by neuroimaging and electrophysiological studies. While these studies have identified a correlation between DLPFC activity and rule maintenance, deactivation studies allow us to establish a causal relationship. Here we have examined the effect of bilateral deactivation of areas 46 and 9/46d on rule maintenance, while a monkey (Macacca mulatta) performed blocks of …

Shift Work And Vascular Events: Systematic Review And Meta-Analysis., Manav V Vyas, Amit X Garg, Arthur V Iansavichus, John Costella, Allan Donner, Lars E Laugsand, Imre Janszky, Marko Mrkobrada, Grace Parraga, Daniel G Hackam

Medical Biophysics Publications

OBJECTIVE: To synthesise the association of shift work with major vascular events as reported in the literature.

DATA SOURCES: Systematic searches of major bibliographic databases, contact with experts in the field, and review of reference lists of primary articles, review papers, and guidelines.

STUDY SELECTION: Observational studies that reported risk ratios for vascular morbidity, vascular mortality, or all cause mortality in relation to shift work were included; control groups could be non-shift ("day") workers or the general population.

DATA EXTRACTION: Study quality was assessed with the Downs and Black scale for observational studies. The three primary outcomes were myocardial infarction, …

Calclium-Calmodulin Regulation Of Trpm2 Currents, Brian M. W. Lockhart

Electronic Thesis and Dissertation Repository

TRPM2 (1507 amino acids), a non-selective cation channel with substantial permeability for Ca²⁺, is responsive to oxidative stress, and is a mediator of cell death in several cell types. Ca²⁺-calmodulin has been shown to promote channel activation and inactivation, however the mechanisms are not fully understood. Identifying candidate CaM binding sites using in silico screening, I hypothesized that Ca²⁺-dependent inactivation (CDI) of TRPM2 is mediated by an intracellular CaM binding domain unique from that of activation (406-415AA). I systematically determined the minimum binding domains for three CaM candidate sites on TRPM2’s intracellular domains using …

The Role Of Amino-Terminal In Determining Transjunctional Voltage-Dependent Gating And Unitary Conductance Of Cx36 And Cx50 Gap Junction Channels, Li Xin

Electronic Thesis and Dissertation Repository

Gap junction (GJ) channels directly connect the cytoplasm of neighboring cells, and allow for the transfer of ions and small molecules between two cells. GJ channels are known to be gated by the transjunctional voltage (V_j, the voltage difference between the interiors of adjoining cells), which is referred to as V_j-dependent gating. GJ channels show varying degrees of sensitivity to V_j, depending on the type of connexin(s) comprising the GJ channel. GJ channels formed by different connexins also show unique unitary conductance ranging from ~ 10 pS to ~300 pS. However, the molecular structures …