Digital Commons Network^™

The Effect Of Dendritic Cell Mobilization On Cd8+ T Cell Responses To Influenza A Virus, Adil N. Shivji

Electronic Thesis and Dissertation Repository

Influenza A viruses (IAV) cause respiratory infections with potentially catastrophic consequences. Neutralizing antibodies towards surface proteins of IAV prevent reinfection. However, mutations in these proteins allow the virus to evade these antibodies. Enhancing cytotoxic T cell-mediated immunity has been proposed as an attractive strategy to combat flu. Recombinant human FMS-like tyrosine kinase 3 ligand (FL) is known to mobilize dendritic cells (DCs) in mice. Given that DCs are the most potent antigen-presenting cells, I hypothesized that their mobilization by FL will improve the CD8+ T cell response to IAV. Quantification of CD8+ T cell responses to IAV epitopes by intracellular …

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 …

Functional Significance Of Ilk-Elmo2 Interactions In Epidermal Keratinocytes, Ernest Ho

Electronic Thesis and Dissertation Repository

The epidermis consists of a basal layer of undifferentiated keratinocytes and multiple suprabasal layers of differentiated keratinocytes. Undifferentiated keratinocytes are adherent and highly motile, whereas differentiated keratinocytes are comparatively less motile and downregulate cell attachments to the extracellular matrix. Integrin-linked kinase (ILK) is a scaffold protein implicated in the regulation of many cellular functions in keratinocytes, including cell attachment, migration, phagocytosis, and protein trafficking. To determine the mechanisms by which ILK is involved in these processes, I sought to identify other proteins which may interact with ILK in keratinocytes. I identified Engulfment and Cell Motility 2 (ELMO2) to interact with …

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 …

The Role Of Cystic Fibrosis Conductance Regulator In The Clearance Of Burkholderia Cenocepacia By Macrophages, Hanna Ostapska

Electronic Thesis and Dissertation Repository

Burkholderia cenocepacia is an opportunistic Gram-negative bacterium that causes chronic respiratory infection in cystic fibrosis (CF) patients, leading to rapid decline of lung function. CF patients harbour mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride (Cl) transport channel. B. cenocepacia survive in macrophages by delaying phagosome maturation and exaggerate this strategy in CFTR-defective macrophages. Neutrophils of CF patients display defective Cl transport resulting in impaired chlorination of bacteria via hypochlorous acid (HOCl), resulting in reduced bacterial clearance. I hypothesize that macrophages with dysfunctional CFTR lack sufficient Cl ion levels in their phagosomes for the …

Investigating The Therapeutic Potential Of Salivary Proteins For Oral Diseases, Dusa Vukosavljevic

Electronic Thesis and Dissertation Repository

ABSTRACT

Saliva is responsible for the formation of the acquired enamel pellicle (AEP), a protein

integument formed as a result of selective adsorption of salivary proteins to the enamel

surface. The AEP demonstrates an important role for modulating dental erosion as a

result of its physical properties, along with its salivary and exogenous protein

composition (Chapter 2). In addition, individual proteins that comprise the AEP have

important physiological functions. Histatin 5 (H5) has potent antifungal effect against C.

albicans, the yeast responsible for the initiation of oral candidiasis. We designed an in

vitro model and found, for the first time, …

The Effect Of Surface Treatments And Bonding Agents On The Shear Bond Strengths Of Orthodontic Brackets Bonded To Aged Composite Resin Restorations, Matthew Tse

Electronic Thesis and Dissertation Repository

To compare the mean bond strengths and mode of bond failure,

in vitro, of

five bonding systems (MIP

1, Plastic Conditioner2, Assure2, Scotchbond3, and Transbond

XT

1), when bonding an orthodontic bracket to an artificially-aged composite resin

restoration, with and without mechanical surface preparation with a diamond bur.

Methods:

Class V buccal composite resin restorations were prepared in 240 upper right

central incisor dentoform teeth. The restorations were artificially aged for 35 days,

bonded with metal brackets, stored in distilled water at 37°C for 30 days, thermocycled

for 500 cycles, and subsequently debonded with an Instron universal testing machine. …

Ethnic Identity And The Perception Of Facial Profile Aesthetics: A Preliminary Study, Paul Michael Glasser

Electronic Thesis and Dissertation Repository

In a multicultural society, the orthodontist is often faced with the challenge of interpreting an individual’s aesthetic preferences, which depending on the individual might differ from Eurocentric standards. Psychological researchers have recognized that ethnicity is dynamic, and better defined as a perception of self, influenced by social interaction and cultural involvement. Ethnic identity was investigated using three broad ethnic groups (Caucasian-American, African-American and Asian-American) with an established Multicultural Ethnic Identity Measure (Revised [MEIM-R]). Profiles for males and females of each group were constructed using published soft tissue data. Each profile was modified from subnasale to soft tissue B-point by displacing …

Calcium Phosphate-Based Resorbable Biomaterials For Bone Regeneration, Daniel O. Costa

Electronic Thesis and Dissertation Repository

Bone defects are a prevalent problem in orthopedics and dentistry. Calcium phosphate-based coatings and nanocomposites offer unique solutions towards producing scaffolds with suitable physical, mechanical and biological properties for bone regeneration.

We developed a novel method to synthesize hydroxyapatite (HA) particles with high aspect ratio using sol-gel chemistry and hydrothermal treatment. We obtained tunable pure-phase carbonated-HA in the form of micro/nanorods and nanowires (diameters 25-800 nm). To mimic the structure of bone, HA nanowires were homogenously mixed within poly(ε-caprolactone) (PCL) to produce nanocomposites with improved mechanical properties as determined by uniaxial tensile testing.

Surface chemistry and topography of biomaterials play …

Staphylococcus Aureus Response To Long Chain Antimicrobial Fatty Acids, Benjamin Arsic

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is a common pathogen that has the ability to infect virtually every tissue and organ system of the body. Despite its propensity to cause invasive infection, S. aureus is also a commensal organism, asymptomatically colonizing ~25% of the population. Much research has gone into resolving this paradox, focusing on both human and bacterial factors that may contribute to colonization. Antimicrobial fatty acids present on the skin and in the nasal mucosa are important components of the innate immune system, and thus we undertook to further understand how S. aureus responds to these fatty acids, and how this response …

A Telerobotic Drilling Control System With Haptic Feedback, Faraz Shah

Electronic Thesis and Dissertation Repository

Drilling a borehole is a common method for extracting oil, gas, and natural resources from beneath the surface of the earth. The main topic of this Thesis is the design of control algorithms for virtual reality based telerobotic system with haptic feedback that allows for the remote control of the vertical drilling operation. The human operator controls the vertical penetration velocity using PHANTOM Omni haptic device while simultaneously receiving the haptic feedback from the locally implemented virtual environment. The virtual environment is rendered as a virtual spring with stiffness updated based on the estimate of the the stiffness of the …

Immune Responses To Homocitrullinated Protein/Peptide In Rheumatoid Arthritis, Mathias J. Scinocca

Electronic Thesis and Dissertation Repository

Rheumatoid Arthritis (RA) is an inflammatory autoimmune disease which causes joint destruction. RA pathogenesis involves citrullinated peptides binding to the shared epitope (SE) during autoantigen presentation, and subsequent Anti-Citrulline Antibody (ACA) production. Their target, citrulline, is very similar to homocitrulline.

The main objective of this study was to investigate anti-homocitrulline immune responses in RA. Specifically, it investigated if: i) Anti-Homocitrulline Antibodies (AHA) were RA specific by screening patients with various inflammatory rheumatic diseases and healthy individuals. ii) ACA also bound homocitrulline by affinity purification and characterization. iii) anti-homocitrulline immune responses involved the SE by computer modelling and immunization of mice. …

Identification Of A Molecular Opiate-Addiction Memory Switch In The Basolateral Amygdala, Danika C.A. Lyons

Electronic Thesis and Dissertation Repository

The molecular mechanisms involved in acquiring opiate-related associative memories are largely unknown. One neural region implicated in the formation of opiate-related memories is the basolateral nucleus of the amygdala (BLA). Transmission through dopamine (DA) receptors within the BLA controls the formation of opiate-related reward memories (Lintas et al., 2011; Lintas et al., 2012). Specifically, transmission through DA D1 receptors controls opiate reward memory formation in animals that are previously naïve to opiate exposure. However, once opiate dependence and withdrawal are present, intra-BLA DA-mediated control of opiate reward memory processing switches to a DA D2 receptor substrate. These findings demonstrate a …

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 …

Investigations Of The Biological Consequences And Cultural Motivations Of Artificial Cranial Modification Among Northern Chilean Populations, Christine E. Boston

Electronic Thesis and Dissertation Repository

The purpose of this study is to build on existing normative models of craniofacial growth and previous craniofacial studies of artificial cranial modification (ACM) in order to deepen the cultural and biological understanding of the this practice. Areas of concentration include a study of the biological changes to cranial epigenetic traits and facial metrics related to ACM, an examination of the biological effects of ACM in order to assess their implications on morbidity and mortality, and an investigation into the cultural motivations for ACM. Three hypotheses were tested: 1) ACM did not affect epigenetic trait incidence or facial metrics; 2) …

Role Of Il-10 In The Immune Response To Staphylococcus Aureus Nasal Carriage, Teresa Fernandez Plaza

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is a human pathogen with the potential to cause life-threatening diseases, but it can also be found as a commensal in up to 50% of the population. Its main reservoir is located in the nostrils, where macrophages are the principal mucosal APC and elicit a predominantly IL-10 response. Induction of IL-10 requires phosohoinositide 3-kinase activity, upon stimulation with S. aureus ligands through toll-like receptor 2 binding. It is hypothesized that IL-10 production by macrophages in the nasal mucosa allows S. aureus to persist in this niche as a commensal. To test this hypothesis, a cohort of S. aureus …

Flexible Workplace Practices In Small It Firms: A Multiple Case Study, Catherine E. Gordon

Electronic Thesis and Dissertation Repository

Flexible workplace practices (FWPs), such as flex-time and working from home, facilitate employees’ work-life balance or integration and enhance their quality of work. Yet, their use is constrained by time-oriented and gendered workplace cultures. Typically past research involves either a quantitative analysis of individual-level data or a qualitative examination of a single large firm. Meanwhile inCanada, small businesses (with less than 100 employees) employ 48 percent of the total labour force in the private sector (IndustryCanada, 2010). In this dissertation, I investigate the FWPs available and used at small information technology (IT) firms. Cross-firm comparisons are made with respect to …

Design Of A User Interface To Investigate The Role Of 3d Spatial Reasoning In Surgical Training, Ladan Ashrafi

Electronic Thesis and Dissertation Repository

In this thesis, a 3D interactive environment for measurement of spatial ability using Mental Rotation Test was designed and implemented. The spatial ability of two groups of participants (novices and experts) was evaluated using the implemented software and compared to the result from Embedded Figure Test. In Embedded Figure Test, only 15.63% of the experts’ responses were incorrect (with score of 6.75 ± 1.50 out of 8), compared to 57.00% for novices (with score of 3.44 ± 1.51). No significant difference was found between scores of the two group from Mental Rotation Test; however, experts responded significantly faster than novices …

Hearts And Minds: Examining The Evolution Of The Egyptian Excerebration And Evisceration Traditions Through The Impact Mummy Database, Andrew D. Wade

Electronic Thesis and Dissertation Repository

Egyptian mummification and funerary rituals were a transformative process, making the deceased a pure being; free of disease, injury, and disfigurements, as well as ethical and moral impurities. Consequently, the features of mummification available to specific categories of individuals hold social and ideological significance. This study refutes long-held classical stereotypes, particularly dogmatic class associations; demonstrates the apocryphal nature of universal heart retention; and expands on the purposes of excerebration and evisceration implied by synthetic and radiological analyses.

Features of the embalming traditions, specifically the variable excerebration and evisceration traditions, represented the Egyptian view of death. Fine-grain analyses, through primary imaging …

Coping Experiences Of 911 Communication Workers, Sarah G. Horsford

Electronic Thesis and Dissertation Repository

This research explored coping experiences among emergency communications personnel. Ten individuals from a communication centre of a policing unit in Ontario participated in semi-structured interviews. Seven themes emerged to form the content analysis including Meaning-Focused Coping, Emotion-Focused Coping, Problem-Focused Coping, Reappraisal, Comm Centre Culture, Occupational Dimensions and Organizational Structure. Themes were compared to workplace stress, coping and burnout literature in addition to literature regarding organizational interventions and emergency responders. Implications were presented for counselors working with communications personnel and emergency responders.

Restriction Of Hiv-1 Replication By Unique Trim22 Isoforms., Clayton Hattlmann

Electronic Thesis and Dissertation Repository

Understanding how the immune system reacts to HIV infection and why normal antiviral defenses are insufficient to fight infection is a key step towards creating better therapies. Several interferon-induced proteins, such as the tripartite motif protein TRIM22, are capable of restricting HIV-1 replication; however single nucleotide polymorphisms (SNPs) can dramatically impact the actions of these proteins. While the trim22 gene contains numerous SNPs, no study has addressed how these may affect TRIM22 functions. Here we provide the first direct comparison of two TRIM22 unique isoforms. Through confocal microscopy we observed these isoforms exhibit different patterns of localization. In vitro studies …

Bacterial Cellulose Templates For Nano-Hydroxyapatite Fibre Synthesis, Jordan A. Demello

Electronic Thesis and Dissertation Repository

Guided bone regeneration is a medical procedure which induces in vivo re-growth of bone using membranes and osteopromoting fillers. In this work, bacterial cellulose fibers were isolated and used as a basis for biomimetic hydroxyapatite growth, with the ultimate goal of producing GBR filler materials. Acetobacter xylinum generated BC using various carbon sources. Fibers were treated with phosphoric acid to phosphorylate functional groups and preconditioned with calcium to nucleate the HA. Simulated body fluid (SBF) furthered the growth. Over 14 days, the product was characterized via EDX, SEM, FTIR, and XRD. The effect of media composition, phosphorylation time, pretreatment, and …

Modulatory Effects Of North American Ginseng Extracts On Human Innate And Adaptive Immune Responses, Holly Rebecca Lemmon

Electronic Thesis and Dissertation Repository

Ginseng has played a vital role in traditional Chinese medicine for thousands of years. There are 22 variants of ginseng including North American ginseng (Panax quinquefolius) and Asian ginseng (Panax ginseng). The use of North American ginseng has increased dramatically and there is a strong need to understand its immunomodulatory effects. This is because the majority of current research focusing on the Asian ginseng variant. Human peripheral blood mononuclear cells (PBMC) were used to test the immunomodulatory properties of 3 North American ginseng extracts, COLD-FX^® and deglycosylated individual ginsenosides. Microarray analysis of PBMC exposed to …