Examining The Role Of Chloride Homeostasis And Pge2 Signaling In The Neuroendocrine Stress Response To Inflammation, Samuel A. Mestern

Electronic Thesis and Dissertation Repository

The brain senses inflammatory signals and drives the release of glucocorticoids (GCs) — potent immunosuppressants — via the activation of the hypothalamic-pituitary-adrenal (HPA) axis. This inflammation-induced HPA axis activation is largely mediated by prostaglandin E2 (PGE2), acting on two subtypes of the PGE2 receptor, EP1 and EP3. Recently, our group revealed EP3 signaling mechanisms that excite HPA axis regulatory neurons. This thesis sought to tease out the remaining EP1 signaling mechanisms. Considering that the excitability of HPA axis regulatory neurons is constrained by GABA_A receptor-mediated synaptic inhibition that relies on low-level intracellular Cl^-. We hypothesized that PGE2-EP1 …

Debt And Stress Amongst Orthodontic Residents, Timothy Renison

Electronic Thesis and Dissertation Repository

Background: The cost of education to become an orthodontist has increased significantly over recent years which has led to an increase in debt of graduating orthodontists.

Aim: This paper aims to assess whether debt amongst orthodontic residents in North America is associated with their stress levels, attitudes towards debt, financial literacy and mathematics anxiety.

Materials and Methods: Web-based software was used to fabricate a questionnaire, based on previously validated scales, in which respondents were asked questions regarding their debt levels, stress levels, attitudes towards debt, financial literacy and math anxiety.

Results: A total of 101 orthodontic residents completed the online …

Applications Of Hair As A Record Of Systemic Exposure To Cortisol, Jeffrey Matthew Levine

Electronic Thesis and Dissertation Repository

Hair cortisol content (HCC) is a novel biomarker that uniquely captures retrospective systemic cortisol exposure. This thesis aimed to assess how different hair growth rates effect HCC timelines in Cushing’s and Addison’s patients, investigate the relationship between HCC and age, puberty, sex and BMI in healthy children and adolescents, and assess novel methods to improve cortisol extraction and recovery. Retrospective HCC timelines derived from a 0.75 cm/month growth rate best matched 50% of patients’ medical records rather than the historically assumed 1 cm/month. HCC correlated positively with age (p<0.0001), puberty status (p<0.001), and BMI (p<0.01) in males and females 7-17 years old. Nitrogen evaporation resulted in greater cortisol recovery than air evaporation (p=0.0003), and hair digestion using NaOH resulted in more rapid extraction of cortisol. These results provide incremental improvements to previous methods and assumptions for HCC analysis and elucidate normal HCC changes in children and adolescents.

High Frequency Oscillations Are Phase-Amplitude Coupled In Stress Induced Seizures Following Traumatic Brain Injury, Paul Jung

Electronic Thesis and Dissertation Repository

Traumatic Brain Injury (TBI) often leads to the development of epilepsy, especially with the occurrence of stressful events. Stressors increase the levels of corticotropin-releasing factor (CRF) in the amygdala, which can be damaged by the secondary effects of TBI. It is hypothesized that the activity of CRF receptor type 1 (CRFR₁) in the amygdala is altered post-TBI and supports the generation of epileptiform waves, namely high-frequency oscillations (HFOs). Sprague-Dawley rats were given a moderate TBI and in vivo recordings of the amygdala were taken during the administration of an acute tail pinch stressor. The stressor increased broadband activity …

Weathering The Storm: Physiological And Behavioural Responses Of White-Throated Sparrows To Inclement Weather Cues, Andrea C. Boyer

Electronic Thesis and Dissertation Repository

Changes in weather patterns and extreme weather events are becoming more common with the onset of climate change. This predicted increase in severe weather globally is alarming and it draws concern for the adaptability and ultimate survival of many species. It is clear that birds are able to cope with and respond to inclement weather with physiological and behavioural responses in many circumstances, but as environmental conditions become more severe, the adaptive coping responses of many species may be pushed to their limit. As such, it is important to understand the effects that such changes in environmental conditions will have …

Perfectionism And Burnout In University Students: The Influence Of Resilience, Laura M. Ulrich

Brescia Psychology Undergraduate Honours Theses

This study investigated the relationship between perfectionism, resilience, and risk of burnout among university students. The sample consisted of 55 (53 female and two male) Psychology 1000 students from Brescia University College. Self-report questionnaires assessed perfectionism, academic resilience, risk of academic burnout, and perceived stress. Participants were divided into four perfectionism groups: non-perfectionism, pure personal standards perfectionism, pure evaluative concerns perfectionism, and mixed perfectionism. Participants were also divided into a high and low academic resilience group. Individuals with pure personal standards perfectionism had a significantly lower risk of academic burnout compared to those with non-perfectionism, pure evaluative concerns perfectionism, and …

Uncovering A Mystery Of The Isoflavonoid Metabolon: Identification And Characterization Of The Arogenate Dehydratase Gene Family In Soybean, Kelsey Pannunzio

Electronic Thesis and Dissertation Repository

Soybean (Glycine max) is a vastly important, multi-billion dollar global commodity; but this crop’s yields are under threat from the pathogen Phytophthora sojae, which causes extensive stem and root rot in soybean crops. Isoflavonoids, a metabolite class unique to legumes, are a promising research target to combat P. sojae. Isoflavonoids are released as phytoalexins in response to stress, and also facilitate interactions with nitrogen-fixing rhizobial bacteria through nodule formation. An isoflavonoid biosynthesis metabolon was discovered in soybean through co-immunoprecipitation, anchored to the endoplasmic reticulum by isoflavone synthase (IFS) and Cinnamate 4-hydroxylase, two cytochrome P450 enzymes. One of the …

The Effects Of Perceived Predation Threat On Stress Response And Memory In Birds, Chlöe S. N. Carter

Electronic Thesis and Dissertation Repository

This study examined how perception of predator cues, across three sensory modalities, affects physiology and behaviour of songbirds. I hypothesized that the perception of predator threat would elicit physiological and behavioural responses in both acute and chronic exposure conditions. My first study examined the responses of wild-caught black-capped chickadees (Poecile atricapillus) and house sparrows (Passer domesticus), as well as lab-bred zebra finches (Taeniopygia guttata), to acute predation cue exposure by coding video recorded behaviour and corticosterone analysis. My second study examined changes in black-capped chickadees’ foraging behaviour and memory retention after chronic exposure to …

Synaptic Correlates For Stress Sensitization, Julia Kj Sunstrum

Electronic Thesis and Dissertation Repository

The stress response is essential for survival, but it can be detrimental when persistently activated during chronic stress. Therefore, the magnitude of the stress response must be finely-tuned in order to be adaptive. Indeed, an animal’s stress response system normally undergoes habituation that decreases responses to a repeated, familiar stressor. Importantly, the same animal still responds normally, or even becomes sensitized, to an unfamiliar (novel) stressor. This indicates that chronic stress simultaneously induces two opposing types of plasticity, one that underlies habituated responses and another that drives sensitized responses. The activation of the hypothalamic-pituitary-adrenal (HPA) axis — a hallmark of …

The Effects Of Aromatherapy On Stress In A University Population, Theresa L. Flagler

Undergraduate Honours Theses

The purpose of the present study was to determine whether aromatherapy has an effect on stress responses in a population of undergraduate university students at a liberal arts college. To do this, participants were brought to a laboratory room and asked to complete a task designed to increase feelings of stress and anxiety by having participants perform a song in front of the researcher. During this, either water vapor infused with a small quantity of lavender oil or unadulterated water vapour was diffusing into the room. To measure stress, participants wore a heart rate monitor throughout the duration of the …

Understanding Burnout In Undergraduate Students: The Role Of Social Media, Paige Walker

Brescia Psychology Undergraduate Honours Theses

This study investigated different factors relating to undergraduate burnout and whether social media could act as a protective factor. The study group was comprised of 66 female undergraduate psychology students at Brescia University College. Participants completed one questionnaire with seven subscales which measured the following variables: subjective well-being, student subjective well-being, personality traits, social support, stress, online support, and burnout. The participants were divided into three groups based on their burnout scores. The results of the ANOVA indicated that there were significant differences between the three burnout groups on: subjective well-being, student subjective well-being, conscientiousness, extraversion, openness, social support, and …

Anxiety And Stress In First Year University Students, Kimberly Mccready

Brescia Psychology Undergraduate Honours Theses

The purpose of the study was two-fold: to confirm the finding that anxiety and stress increases as exams draw near, and to provide evidence that smokers will have greater increases in anxiety and stress than non-smokers, as well as increased smoking urges as exam draws near, to deal with the related increase in anxiety and stress. To investigate this, participants were asked to fill out the DASS-21 at three-time points (4 weeks, 2.5 weeks, and 1 week) before the Psychology 1000 midterm examination. Smoking urges of smokers was also to be assessed, however, due to lack of smoking participants, no …

Neuronal Correlates For Neuroendocrine Habituation To Repeated Stress, Sara Matovic

Electronic Thesis and Dissertation Repository

One way that the body actively responds to an impending stressor is by increasing systemic glucocorticoids through the activation of the hypothalamic-pituitary-adrenal (HPA) axis. While it is essential for short-term adaptation to stress, the sustained activation of the HPA axis during chronic stress can be detrimental and is linked to stress-related psychiatric conditions such as anxiety and depression. Therefore, it is important that the HPA axis adapts, or habituates, during chronic stress to minimize the negative consequences. Corticotropin releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) function to assimilate incoming information from the stress circuitry and …

Early Life Immune And Physical Stress Directly Influences Anxiety-Like Behaviour In Adolescent Rats: Examining Sex Differences, Jordan M. Ward

Electronic Thesis and Dissertation Repository

This thesis examined the effects of neonatal acute immune activation with the endotoxin, lipopolysaccharide (LPS) on postnatal days 3 and 5 on adolescent anxiety-like behaviour in rats before and after a stress period. Previous research has shown that adults rats exposed to LPS during the neonatal stage show anxiety-like behaviour following a period of stress. This thesis investigated this effect in adolescence. The present results showed significantly higher anxiety-like behaviour in saline controls, and a potential neuroprotective effect of low dose LPS (15 µg/kg) contrary to what was reported in adult rats. As well, a phase of stressful, aversive conditioning …

Understanding Workplace Incivility Experiences And The Moderating Role Of Mindfulness, Rima C. Tarraf

Electronic Thesis and Dissertation Repository

Rude treatment at work can lead to many negative consequences, as evidenced by the wealth of research available. This dissertation, addressed two important questions that have yet to receive adequate attention. First, how does an employee experience incivility, and second, what is a practical and cost-effective way of mitigating the negative outcomes associated with incivility and promoting positive ones? Incivility research has mainly employed quantitative methods to understand incivility experiences. Using qualitative methods however, would complement the knowledge and potentially move the field of inquiry in new directions. As such, the goal of Study One was to obtain a narrative …

Resiliency In The Operating Room: Exploring Trainee Stress During Surgery And The Role Of Individual Resilience, Richard Ng

Electronic Thesis and Dissertation Repository

Surgical trainees experience significant intraoperative stress, which can negatively impact performance and learning. Psychological resilience suggests why some individuals excel despite severe stress. This study explores the relationship between trainee resilience and intraoperative stress. A novel instrument was developed to assess Surgical TRainee Experiences of StresS in the Operating Room (STRESSOR). Focus groups and a literature review identified eight domains of intraoperative stress. STRESSOR was used in a survey of orthopaedic residents in Canada and surgical trainees at Western University. Resiliency was assessed using the 10-item Connor-Davidson Resiliency Scale. 171 responses were received for a 38 percent response rate. The …

Dads And Dyads: Stress And Coping When A Child Has Retinoblastoma, Rob Downie

Electronic Thesis and Dissertation Repository

Child psychosocial oncology research offers limited examination of fathers’ and dyadic stress and coping. Retinoblastoma (Rb) is a rare genetic eye cancer occurring at birth or early childhood. This qualitative sociological study examines individual and dyadic stress and coping across 4 fatherhood role categories when their child is diagnosed/treated for Retinoblastoma. Using purposive sampling, 23 Canadian Rb couples and 7 unmatched parents completed individual in-depth, semi-structured interviews. Findings confirm fatherhood role identity is diverse, influenced by the current situation, elements of discourse, and cultural references. Often contested in public and private spheres, fathering roles show transitional or permanent change tied …

Quality Of Life And Sources Of Stress In Teachers: A Canadian Perspective, Jessica R. Danilewitz

Electronic Thesis and Dissertation Repository

Previous research has reported that teaching is one of the most stressful occupations in the world. The present study examined the experience of teachers’ Quality of Life (QOL) and stress, and the relationship between QOL and the source (home life, work-life, or work-life balance) of stress in Canadian teachers. Data for the study was obtained from a comprehensive online survey of female full-time elementary and secondary school teachers across Canada (n = 227). Results demonstrated that all QOL scale scores were lower in the present study, as compared to previously published community sample literature. Of the three sources of stress, …

Examining A Normative Model Of Stress Using Choice Under Risk, Zarmina Khan

Undergraduate Honors Theses

Novel research in the domain of decisional control (DC), the process whereby individuals in multifaceted stressing situations make probabilistic judgments in order to reduce the occurrence of adverse events, has recently tested a mathematically specified normative model of coping with stress. This model used choice under uncertainty to understand the cognitive underpinnings of choice and linked threat. Findings from this undertaking have supported the notion that individualized subjective expected utilities (SEU) provide the best fit over group-averaged SEU and objective utility models in a sample of undergraduate students. The present research examined whether this finding holds true for choice under …

Corticotropin Releasing Factor Receptor Type 1 Signaling In Epilepsy And Traumatic Brain Injury, V V Chakravarthi Narla

Electronic Thesis and Dissertation Repository

Stress increases the frequency by which epileptic seizures occur. Corticotropin-releasing factor (CRF) coordinates neuroendocrine, autonomic and behavioral response to stress. This thesis sought to study the cellular and molecular mechanisms by which CRF regulates the activity of neural circuits in the piriform cortex (PC) in normal and epileptic states. The PC is richly innervated by CRF and 5-HT containing axons arising from the central amygdala and raphe nucleus. CRFR₁ and 5-HT_2A/CRs have been shown to interact in a manner where CRFR activation subsequently potentiates the activity of 5-HT_2A/CRs. The first purpose of this thesis was …

Characterizing The Role Of The Neuropeptide Y-Y5r System In Breast Cancer, Jenna Kara

Electronic Thesis and Dissertation Repository

Studies have demonstrated a correlation between stress and an increased risk of breast cancer. Neuropeptide Y (NPY) is up- regulated in chronic stress and induces proliferation and chemotaxis of 4T1 breast cancer cells via Y5 receptor (Y5R) activation. In the studies performed in this thesis, we characterize NPY-Y5R as a regulatory system that promotes breast cancer metastasis. We compared three cancer cell sublines derived from the same murine mammary fat pad tumour, that greatly differ in metastatic potential (67NR, 168FARN, and 4T1) in addition to a 4T1-Y5R knockdown established in our labs. In this thesis we demonstrate significance of up-regulation …

The Effects Of Self-Care Meditation Behaviour On Undergraduate Students’ Reported Stress, Anna Smallwood

Undergraduate Honours Theses

The goal of this research study was to provide undergraduate post-secondary students with a self-care behaviour that: a) was self-help based; b) could become a routine part of their schedules; and c) was effective in lowering their stress responses. One group of participants was asked to rate their stress on a 7-point scale, twice a day, for 10 business days. A second group of participants was also asked to rate their stress following the same instructions however they were also asked to perform a 5-minute mindfulness-based meditation twice a day, immediately following the stress ratings. A 2 (Week 1 vs. …

Stress And Coping In Adults With Type 2 Diabetes Who Initiate Insulin Therapy, Maureen A. Loft

Electronic Thesis and Dissertation Repository

Type 2 diabetes affects 90% of people who live with this chronic disease. A primary goal of healthcare professionals is to assist patients with Type 2 diabetes to achieve optimal glycemic control to prevent the devastating complications of this disease. Research has demonstrated that optimal glycemic control can minimize or prevent macrovascular complications such as heart attack or stroke and the microvascular complications of retinopathy, nephropathy, and neuropathy. Historically insulin has been one of the last agents to be added in type 2 diabetes despite its efficacy and long term treatment data. Reluctance by both patients and clinicians to add …

Planting The Chalcone Reductase Family Tree: Identification And Characterization Of Chalcone Reductase Genes In Soybean, Caroline Julia Sepiol

Electronic Thesis and Dissertation Repository

Soybean (Glycine max [L.] Merr) is an important crop grown in Canada, generating $2.4 billion in sales. Though this number may be promising, soybean farmers lose about $50 million worth of yield annually due to root and stem rot disease caused by Phytophthora sojae. Many strategies have been developed to combat the infection; however, these methods are prohibitively expensive. A ‘cost effective’ approach to this problem is to select a trait naturally found in soybean that can increase resistance. One such trait is the increased production of root glyceollins. One of the key enzymes exclusively involved in glyceollin …

Interactions Between The Basolateral Amygdala And Ventral Striatum During Probabilistic Learning In Children And Associations With Individual Differences In Free Cortisol, Haley J. Fallowfield

Electronic Thesis and Dissertation Repository

Stress can drastically alter the behavioural and functional correlates of feedback learning; however, the functional correlates of these effects are poorly understood, particularly in children. In the present study, typically developing children between the ages of 9- and 11-years-old completed a probabilistic learning task with both appetitive and aversive outcomes in a magnetic resonance imaging scanner. Anticipatory stress to the experimental environment was measured via salivary cortisol at baseline and prior to completion of the task. Although baseline and pre-MRI cortisol values were not reliably different at the group level, subsequent analyses revealed that the basolateral amygdala was less responsive …

Nursing Students' Understanding And Enactment Of Resilience: A Grounded Theory Study, Andrew T. Reyes

Electronic Thesis and Dissertation Repository

The purpose of this study was to explore nursing students’ understanding and enactment of resilience. Stress is considered to be a major factor affecting the health, well-being, and academic performance of nursing students. Resilience has been extensively researched as a process that allows individuals to successfully adapt to adversity and develop positive outcomes as a result. However, relatively little is known about the resilience of nursing students. A constructivist grounded theory study design was used. In-depth individual interviews were conducted with 38 nursing students enrolled in a four-year, integrated baccalaureate nursing degree program at a university in Ontario, Canada. Face-to-face …

Calmly Coping: A Motivational Interviewing Via Co-Active Life Coaching (Mi-Via-Calc) Intervention For University Students Suffering From Stress, Rebecca R. Fried

Electronic Thesis and Dissertation Repository

The purpose of this semester-long pilot study was to assess the impact of Motivational Interviewing via Co-Active Life Coaching (MI-via-CALC) on the stress management experiences of 30 full-time, English-speaking students aged 17-24 years. Participants’ experiences were assessed quantitatively using the previously validated Perceived Stress Scale and Hospital Anxiety and Depression Scale (which is divided into Anxiety and Depression scales) at pre-, mid-, and post-intervention. Three one-way, repeated-measures ANOVAs were completed for each scale and statistically significant differences in stress reduction were found for all scales between pre-intervention to mid-intervention, and between pre-intervention to post- intervention; no statistically significant differences occurred …

The Stress Process Model For Community-Dwelling Adults With Mental Disorders, Samantha Davie

Electronic Thesis and Dissertation Repository

Background: Although stress has been linked to poor mental health outcomes for various populations, less is known about the impact of stress on individuals already diagnosed with mental disorders. Objective: Explore the association between stress and general psychological distress (GPD), using the stress process model. Design: Data were collected in 2011 from community-dwelling adults who have had at least one diagnosed mental disorder for at least one year in their lifetime (n=380), and are cross-sectional in nature. Multivariable linear regression was used to assess the association between stress and GPD, with various psychological resources, such as coping, social support, and …

Associations Between Hypothalamic-Pituitary-Adrenal Axis System Gene Variants And Cortisol Reactivity In Preschoolers: Main Effects And Gene-Environment Interactions, Haroon I. Sheikh

Electronic Thesis and Dissertation Repository

Exposure to stressful events during early development has consistently been shown to produce long lasting effects on the hypothalamic-pituitary-adrenal (HPA) axis, which may increase vulnerability to mood and anxiety disorders. Recently reported genetic association studies indicate that these disorders may be influenced, in part, by gene-environment interactions (GxE) involving polymorphisms within the corticotrophin-releasing hormone and monoaminergic system genes. However, little is known about how genetic variants and life stress work to shape children’s neuroendocrine reactivity and emerging symptoms. Therefore, the aim of this thesis is to examine main effects of candidate genes and GxE on the neuroendocrine stress response and …

Newcomer Youths' Experiences Of School, Lori-Ann A. Brown

Electronic Thesis and Dissertation Repository

The purpose of the study was to identify positive and negative aspects of school experience among newcomer youth. More specifically, the purpose of this research was to give a voice to a group of newcomers that have been largely ignored by the literature. To accomplish this goal, participants were male and female youth, aged 15 to 18, who had migrated to Canada within the past two years and resided in London at the time of interview. To gather information from participants focus group interviews were conducted with participants from a culturally diverse community centre. The results were analyzed using a …