Health Sciences - Theses, Dissertations, and other Required Graduate Degree Essays

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Relationship between air pollution exposure and systemic inflammation in Canada

Date created: 
2015-08-20
Abstract: 

Research has shown that plausible links between air pollution exposure and both atherosclerosis and diabetes may exist through systemic inflammation. This present study quantified the association between particulate matter less than 2.5 μm and nitrogen dioxide with four biomarkers of inflammation (CRP, fibrinogen, white blood cells, and platelets) in a cross-sectional sample representative of the Canadian population aged between 18 and 79 (N=6322) from cycle 1 and 2 (2007-2012) of the Canadian Health Measures Survey. After adjusting for race, household income and temperature, results showed that daily and annual NO2 was inversely associated with fibrinogen and the associations were slightly stronger among those taking statins, although not clinically significant. Although our results did not support our hypothesis, our findings raise new questions about other possible health effects behind the association between NO2 exposure and fibrinogen.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Scott Venners
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Attempts to visualize lymphocytes latently infected with Marek’s Disease Virus in situ

Date created: 
2015-08-19
Abstract: 

Marek’s Disease (MD) is an avian lymphoma disease caused by an alphaherpesvirus, Marek’s Disease Virus (MDV). Live attenuated vaccines can protect birds from the disease but do not inhibit MDV infection. The co-infection of vaccine virus and virulent MDV perhaps contributed to the emergence of MDV strains that caused vaccine breaks. MDV establishes lytic and latent states of infection but it is during latency that cells can be transformed. This thesis strived to create a tool to visualize latently infected cells that would help reveal the transformation process and underlying mechanisms of the vaccine effect. Toward the goal, I constructed two recombinant MDVs that were designed to express a fluorescent protein during latency. The recombinant MDVs were able to replicate successfully in vitro and in vivo comparatively to parental MDV. They also expressed the fluorescent protein in the infected cells in vitro. However, the expression of the fluorescent protein was not confirmed in vivo and these recombinant MDVs did not cause lymphomas in infected birds.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Masahiro Niikura
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

The climate change, water, and health nexus: an interdisciplinary inquiry

Date created: 
2015-07-08
Abstract: 

Climate change is an issue of unprecedented complexity and a major threat to ecosystem function, water resources, and human health. Although important knowledge gaps exist at the interface of climate change, water, and health, it is increasingly clear that water is a primary medium through which climate change affects health and that knowledge integration and collaboration are needed to understand and address climate change.This dissertation explores the links among climate change, water, and health drawing on interdisciplinary and ecohealth approaches and presents three individual research papers. The first two papers use eleven-years of acute gastro-intestinal illness (AGI) data to generate knowledge about the potential impacts of climate change on waterborne AGI in British Colombia (BC). Using a Geographic Information System and a suite of descriptive methods, the seasonality of AGI is characterized across BC’s major drinking water sources (surface water, groundwater, and mixed water) and hydroclimatic regimes (snowmelt-dominated and rainfall-dominated). Associations between hydroclimatic variables and AGI are assessed using times-series regression analysis. The results show that AGI exhibits seasonality and that hydroclimatic variables play a role in driving the occurrence and variability of AGI. Moreover, the relationships between hydroclimatic variables and AGI differ in the context of the two major hydroclimatic regimes in BC. These results suggest that future climate change will likely lead to a higher burden of AGI in BC, with impacts mediated by context and ecological factors. The third paper is oriented towards climate change policy and action and uses qualitative data and the method of frame analysis to describe the ways in which climate change is framed in public health and water resource management texts. Results show that climate change is framed in numerous ways both within and across these sectors. The notion of frames and the process of frame-reflection may be useful tools to promote integration and collaboration and an opportunity to foster enabling conditions for climate change policy and action.Finally, through a critical reflection on the research findings and the research process, implications for interdisciplinary research and collaborative action are synthesized and presented.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Tim Takaro
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

Nursing Praxis, Racialization, and ‘Othering’: An Ethnography of Breastfeeding Promotion in Urban, Western Canada

Date created: 
2015-08-10
Abstract: 

This thesis examines how public health nurses (PHNs) racialize and ‘other’ mothers during the postpartum period. This study was conducted over seven months in urban, western Canada. Ethnographic methods included participant-observation, semi-structured interviews, and gray literature analyses. They helped to uncover the multifaceted ways public health nursing praxis reproduces and reifies racialized notions of ‘Chinese’ mothers in breastfeeding promotion contexts. I find that the historical professionalization of nursing, the medicalization of breastfeeding, and health promotion protocols shape how PHNs ascribe ‘race’ to women in relation to infant feeding. Further, racialized stereotypes and acts of ‘othering’ are concretized in nursing praxes. Even as nurses sometimes actively resist and regret these stereotypes, they nevertheless create contexts of exclusion that reinforce boundaries of citizenship and belonging for postpartum mothers and their infants. Most significantly, clinical practices pervasively mired in raced ideas of ‘others’ lead to differential care for mothers and their infants.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Susan Erikson
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

The Role of the Retinoblastoma Protein on Hypoxia-Inducible Factor Dependent Tumor Cell Transformation: Microarray Validation

Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2015-08-26
Abstract: 

Intratumoral hypoxia results in tumour cell adaptations mediated by the hypoxia inducible factor 1-α (HIF1-α) and its dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT). This process is attenuated by the retinoblastoma protein (Rb) via its association with the thyroid hormone receptor/retinoblastoma interacting protein (TRIP230). This study’s aim was to examine the role of Rb on HIF1 tumour cell transformation. By interrogating the transcriptome of human MCF-7 and LNCaP cells using gene expression microarrays, we developed a list of 21 common HIF1 target genes further up-regulated following loss of Rb. Real-time PCR, immuno-blotting and immuno-cytochemistry were used to validate mRNA and protein levels of genes. Wound healing assays were used to measure cell migration following loss of Rb and hypoxia. Results show loss of Rb exacerbates the expression of HIF1 genes associated with neuroendocrine differentiation; however no change in cell migration was observed.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Timothy Beischlag
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) M.Sc.

Social marketing: Pitfalls and promise for change

Author: 
Date created: 
2015-07-29
Abstract: 

Background: Since 1971, social marketing (SM) has been adopted as a behaviour change approach to address various social issues, including those of public health and the environment. In a context of proliferating health promotion and intervention approaches, as well as a changing communication environment, SM as a field has had to respond to various challenges. The purpose of this research was to explore the current context of SM, understand the challenges to the practice of SM, and explore its fit as a strategic framework within a broader set of public health oriented social change planning and implementation approaches currently in use. Specifically, the research objectives were to a) explore how the core constructs of SM were being represented and implemented, b) identify the challenges practitioners were facing in adopting and implementing SM, and c) assess the current position of the discipline within the broader social change landscape through three unique assessments. Methods: A multiple methods case study research design was employed to address the research objectives. First, semi-structured interviews were conducted with renowned experts/leaders (n = 16) in the field of SM. Next I carried out a scoping review of literature examining the use of SM in the prevention of chronic disease. Finally, semi-structured interviews with practitioner end users (n = 9) of SM elicited their perspectives and provided, along with the other studies, data for exploring how to design SM so that it is an accessible and desirable tool for social change. Results: Results of each study are reported separately before integration, however, data from across all three resulted in consistent themes. Data from experts, the scoping review, and end users illustrated strong endorsement of the approach, but concerns about its current directions and status were acknowledged. Although SM has reportedly achieved success in its efforts, results highlighted challenges for the discipline of SM. Assertions for SM included the need for consensus about appropriate benchmark criteria, more effectiveness studies, inconsistencies in the application of SM approaches, the need for continued and sustained leadership, and the ability to be innovative in the design and delivery of social marketing efforts. Diffusion of Innovations theory provided a useful framework for summarizing the critical considerations that may enhance the continued sustainability of SM as both an approach to social change in public health and as a discipline. Conclusion: This dissertation provides a unique glance at how SM can be adapted to better serve academics and practitioners in their pursuit of behavioural and upstream change objectives. Relevance, evidence, audience perspective and leadership must all be considered to move SM forward as a primary tool for social change.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Kitty Corbett
Department: 
Health Sciences: Health Sciences
Thesis type: 
(Dissertation) Ph.D.

Examination of HIV evolution in response to host pressures

Author: 
Date created: 
2015-06-12
Abstract: 

The overarching aim of this thesis was to study the evolution of HIV-1 in response to host pressures. The main data chapter comprises a detailed HIV-1 transmission study where we identified a putative case of X4 HIV-1 transmission from a CCR5-wt/wt donor to a recipient homozygous for the naturally-occurring 32 base pair deletion in the CCR5 gene (CCR5-∆32/∆32). This rare genotype confers resistance to infection by CCR5-using (“R5”) HIV-1 strains not CXCR4-using (“X4”) strains. Using ultradeep sequencing and phylogenetic analysis, we estimate the number of founder viruses that established infection in both donor and recipient (one in each case), reconstruct their sequences, and study within-host HIV-1 evolution and coreceptor usage. Notably, results suggest that HIV-1 infection in the recipient was initiated by transfer of an infected cell (i.e. not a virion) from the donor, and reveal differential HIV-1 evolution in both members of the pair.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Zabrina Brumme
Department: 
Health Sciences: Health Sciences
Thesis type: 
(Thesis) M.Sc.

Banging down doors: parents' experiences of gaining access to autism care services

Author: 
Date created: 
2015-04-22
Abstract: 

Although a great amount of attention has been recently paid to the state of autism care services in Ontario, little of this attention has been focused on the services for school-aged children and the services in rural-remote regions. This study presents the access experiences of three parents of school-aged children (ages 4-12) in Northwestern Ontario. Parents take on the role of the Navigator-Advocate in order to facilitate access to services for their child in three identified systems: education, health and medical services, and community-based services. Key themes in parents’ experiences include having their experience of a service being dependent on a particular individual, a lack of compassionate understanding from others, insufficiently educated service providers, and exclusion. Parents’ experiences of access could be ameliorated through the development of an integrated care model for autism that is responsive to navigational experiences and the geographical and human resource challenges of Northwestern Ontario.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Malcolm Steinberg
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.P.H.

Intersecting Risk Factors: Diagnosed Alcohol Dependence and Criminal Sentencing in British Columbia’s Aboriginal Populations

Date created: 
2015-04-14
Abstract: 

Alcohol use is commonly reported as a short-term criminal risk factor; however there is minimal research on long-term effects of alcohol misuse on crime. Canadian Aboriginal offenders exhibit both disproportionate crime and alcohol disorder prevalence. This thesis examines the impact of diagnosed alcohol dependence on Aboriginal ethnicity and criminal sentencing in British Columbia (BC). An administrative linkage database was used to develop a retrospective cohort of 77719 offenders sentenced through BC courts from 2001-2010. A coefficient difference mediation analysis was used to evaluate the mediating effect of alcohol dependence. Adjustment for alcohol dependence rate resulted in a small and statistically insignificant change in the sentencing rate (2%, 95% Confidence Interval: -13%, 14%). This study demonstrates that alcohol dependence does not have a mediating effect on sentencing rate among BC offenders. Nonetheless, the prevalence of alcohol dependence suggests that alcohol misuse is an important health policy target among offenders.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Lawrence McCandless
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.Sc.

A Qualitative Exploration of Injection Cessation among Youth in Vancouver, BC

Date created: 
2014-10-10
Abstract: 

Cessation of injection drug use among youth is an important public health objective that has potential to reduce injection-related harm. We undertook this qualitative study to examine experiences of injection cessation and relapse among young people living in Vancouver, BC. Participants were recruited from the At-Risk Youth Study (ARYS), a longitudinal cohort of street-involved youth who use illicit drugs. Twelve semi-structured interviews were conducted with 7 females and 5 males, ages 20 to 30 years. Interviews were audio-recorded, transcribed verbatim, and a thematic analysis was conducted, drawing on the risk environment framework. In this study, facilitators of injection cessation were low-barrier and integrated youth services, supportive housing, access to methadone maintenance therapy (MMT), and the use of marijuana. Based upon these findings, recommendations for promoting injection cessation include increasing access to low-barrier supports for youth, and promoting non-injection routes of administration to reduce the health consequences of injection drug use.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Cari Miller
Department: 
Health Sciences:
Thesis type: 
(Thesis) M.Sc.