The validation of heart rate variability in individuals with spinal cord injury

The current classification system for spinal cord injury (SCI) considers only somatic information and neglects autonomic damage after injiuy. Heart rate variability (HRV) has the potential to be a valuable measure of cardiac autonomic control after (SCI). Five individuals with tetraplegia and four able-bodied controls underwent 1 min continuous ECG recordings during rest, after Metoprolol administration (max dose=3x5mg) and after Atropine administration (0.02mg/kg) in both supine and 40° head-up tilt. After Metoprolol administration there was a 61.8% decrease in the LF:HF ratio in the SCI participants suggesting that the LF:HF ratio is a reflection of cardiac sympathetic outflow. After Atropine administration there was a 99.1% decrease in the HF power in the SCI participants suggesting that HF power is highly representative of cardiac parasympathetic outflow. There were no significant differences between the SCI and able-bodied participants. Thus, HRV measures are a valid index of cardiac autonomic control after SCI.

Response rainbow trout (Salmon gairdneri) blood gas transport system to temperature, oxygen availability and photoperiod

Hematological status in rainbow trout, Salmo gairdneri, was examined in relation to eight combinations of three environmental fa ctors; temperature (5°, 20°C), oxygen availability «35%, >70% saturation) and photoperiod (16L:8D, 8L:16D) and evaluated by 3-factor analysis of variance. Hemog l obin and hematocrit , indicators of oxygenc arrying capacity increased significantly at the higher temperature, following exposure to hypoxia and in relation to reduced light period. Significant variations in mean corpuscular hemoglobin concentration were not detected. The effects of temperature and oxygen availability were more pronounced than that of photoperiod which was generally masked. Although oxygen availability and photoperiod did not interact with temperature, the interaction of the former fac tors was significant. Elec trophoresis revealed twelve hemoglobin isomorphs. Relative concentration changes were found in re lation to the factors c onsidered with temperature>hypoxia>photoperiod. Howeve r , in terms of absolute concentration, effects were hypoxia>temperature>photoperiod. Photoperiod effects were again masked by temperature and (or) hypoxia. Red cell +2 l eve ls of [CI ] and [Mg ], critical elements in the hemoglobin-oxygen affinity regulating system, were also significantly altered. Red cell CI +2 was influenced only by temperature ; Mg by temper ature and oxygen. No photoperiod influence on either ions was observed. Under nominal 'summer' conditions, these changes point to the likelihood of increases in oxygen-c arrying c apac ity coupled with low Hb-02 affinity adjustments which would be expected to increase oxygen delivery rates to their more rapidly metabolising tissues.

Autonomic regulation and blood pressure in children

Vagal baroreflex sensitivity (BRS) is a measure of short term blood pressure (BP) regulation through alterations in heart rate. Low BRS reflects impaired autonomic system regulation and has been found to be a surrogate marker for cardiovascular health. In particular, it has found to be associated with the pathogenesis of adult hypertension. However, only limited information exists as to the negative consequences of childhood BP on baroreflex function. The objective of this study was to investigate BRS in children with 2 different BP profiles while controlling for the effects of age, maturation, sex, and body composition. A preliminary subsample of 11-14 year-old children from the HBEAT (Heart Behavioural Environmental Assessment Team) Study was selected. The children were divided into 2 BP groups; high BP (HBP; 2:95tl1 percentile, n=21) and normal BP (NBP; <90th percentile, n=85). Following an initial 15 minutes of supine rest, 5 minutes of continuous beat-to-beat BP (Finapres) and RR interval (RRI) were recorded (standard ECG). Spectral indices were computed using Fast Fourier Transform and transfer function analysis was used to compute BRS. High frequency (HF) and low frequency (LF) power spectral areas were set to 0.15-0.4 Hz and 0.04-0.15 Hz, respectively. Body composition was measured using body mass index. After adjusting for body composition, maturation, age and sex ANCOV A results were as follows; LF and HF BRS, LF and HF RRI, and RRI total power were lower in the HBP versus NBP participants (p<0.05). As well, LF IHF SBP ratio was significantly higher in the HBP compared to the NBP group (p<0.05). The regression coefficients (unstandardized B) indicated that in changing groups (NBP to HBP) LF and HF BRS decreases by 4.04 and 6.18 ms/mmHg, respectively. Thus, as BP increases, BRS decreases. These data suggest that changes in autonomic activity occur in children who have HBP, regardless of age, sex, maturation, and body composition. Thus, despite their young age and relatively short amount of time having high BP compared with adults, these children are already demonstrating poor BP regulation and reduced cardiovagal activity. Given that childhood BP is associated with hypertension in adulthood, there is a growing concern in regards to the current cardiovascular health of our children and future adults.

The association between blood pressure and vascular characteristics in children

Hypertension is thought to exist in up to five percent of children. A select number of studies have investigated the role elevated blood pressure plays in pediatric atherosclerotic progression. However these studies contain significant methodological flaws and fail to recognize important confounding factors. Therefore, the influence of elevated blood pressure on arterial health in children remains to be clearly understood. The purpose of this study was to investigate the association between blood pressure (BP) and arterial thickness and stiffuess in children. Common carotid artery (CCA) intima-media thickness (IMT) and distensibility (Dist), as well as systemic pulse wave velocity (PWV) were measured in 21 elevated blood pressure (EBP; BP ~ 95th percentile) and 83 normal blood pressure (NBP; BP < 90th percentile) children 11-14 years of age. Both EBP and NBP groups demonstrated BP within the normal clinical range, but EBP showed significantly elevated BP as compared to the NBP group. Independent t-tests failed to show significant differences between the EBP and NBP groups for CCA IMT (0.43 ± 0.05 mm and 0.42 ± 0.06 mm, respectively) and Dist (0.0058 ± 0.0024 mmHg-1 and 0.0064 ± 0.0019 mmHil respectively). In contrast, a significantly elevated PWV (p

The Structural and Functional Changes of Blood Vessels during Aging

The vascular adventitia is recognized as a dynamic mediator of vascular structure and function, yet its role in aging is not understood. The purpose of this thesis was to examine the age-related changes of the vascular adventitia and determine the underlying mediators responsible. Male Sprague-Dawley rats were aged to 15, 30, 50 and 80 weeks before being anesthetised and euthanized by exsanguination. Thoracic aortas, mesenteric and pudental arteries were isolated, formalin fixed, and embedded in paraffin then sectioned at 5μm. Vessels were examined by microscopy and protein expression was determined by indirect immunofluorescence. The thickness of the adventitia increased dramatically with age. Immunofluorescence revealed a robust expression of endothelin system proteins in the adventitia. Additionally, extracellular matrix proteins collagen and fibronectin, and the proliferation marker Ki67 showed strong adventitial origin. The changes observed in the vascular adventitia with aging clearly demonstrate an important role in the process of vascular aging.

A possible role for chemokine signalling through CXCR4 as a downstream effector of retinoic acid signalling in the regenerating tail and spinal cord of Notophthalmus viridescens

The newt, Notopthalmus viridescens is one of the few tet rapod vertebrates capable of extensive regeneration of the central nervous system, however, the factors involved in this process are still unknown. Chemokine signalling through the receptor CXCR4, has been found to be involved in the development of the central nervous system of mammals and more recently in epimorphic fin regeneration in zebrafish. We have hypothesized that the CXCR4 signalling pathway is involved in spinal cord and tail regeneration in the adul t newt , possibly as a downstream target of retinoic acid signalling. We found that CXCR4 mRNA expression was observed in the brain, spinal cord, heart, gut, liver and regenerating tail blastemas. CXCR4 expression increased over the f i rst 12 days of tail regeneration and returned to basal expression levels at day 21 of regeneration. Inhibition of CXCR4 wi th AMD3100, a specific receptor antagonist, led to a decrease in CXCR4 mRNA in the regenerating tail 14 days post amputation. Histological analysis suggests a delay in the early stages of tail and spinal cord regeneration. Spinal cord explants t reated wi th CXCL12, the ligand to CXCR4, displayed enhanced neurite outgrowth in vitro. Explants t reated wi th AMD3100 abolished any retinoic acid enhanced neurite outgrowth effects suggesting a link between these signalling pathways.

The structural and functional changes of blood vessels during aging

The vascular adventitia is recognized as a dynamic mediator of vascular structure and function, yet its role in aging is not understood. The purpose of this thesis was to examine the age-related changes of the vascular adventitia and determine the underlying mediators responsible. Male Sprague-Dawley rats were aged to 15,30,50 and 80 weeks before being anesthetised and euthanized by exsanguination. Thoracic aortas, mesenteric and pudental arteries were isolated, formalin fixed, and embedded in paraffin then sectioned at 51lm. Vessels were examined by microscopy and protein expression was determined by indirect immunofluorescence. The thickness of the adventitia increased dramatically with age. Immunofluorescence revealed a robust expression of endothelin system proteins in the adventitia. Additionally, extracellular matrix proteins collagen and fibronectin, and the proliferation marker Ki67 showed strong adventitial origin. The changes observed in the vascular adventitia with aging clearly demonstrate an important role in the process of vascular aging.

The Effect of Functional Electrically Stimulated Ambulation Training on Locomotor Function and Quality of Life in Individuals With Incomplete Spinal Cord Injury

The purpose of this study was to investigate the effects of a 12-week FES-ambulation program on locomotor function and quality of life after incomplete spinal cord injury. Six individuals with incomplete SCI participated in the study. Over-ground walking endurance (6MWT), speed (10MWT), independence (WISCI II) and body-weight support were assessed. Quality of life was assessed via the SF-36, WHOQOL-BREF, Perceived Stress Scale, Center of Epidemiological Studies for Depression scale, and task self-efficacy. Participants experienced significant improvements in walking endurance (223.6±141.5m to 297.3±164.5m; p=0.03), body-weight support (55.3±12.6% to 14.7±23.2%; p= 0.005) and four of the six participants showed improvements on the WISCI II scale (1-4 points). In addition, there was a significant reduction in reported bodily pain (6.5±1.2 to 5.0±1.7; p=0.04). Therefore, FES-ambulation is an effective means for enhancing over-ground locomotor function in individuals with incomplete SCI. It may also be an effective method for reducing pain in individuals with SCI.

Utilizing a Phenomenological Approach to Examine the Experience of Sexuality for Women Concerned about Urinary Incontinence following Spinal Cord Injury

Sexuality after spinal cord injury (SCI) is a complex issue that is influenced by a number of social, psychological and physiological factors, one of which is urinary incontinence (UI). Using a phenomenological approach, seven mixed methods interviews combining both the interview guide and standardized open-ended approaches were conducted to examine the experience of sexuality for women who are concerned about UI following SCI. Sexual function was one of the top priorities for the women after SCI, and UI was one of the main concerns the women had regarding sexuality. The findings of this study demonstrate that various dimensions of intimacy and the sexual experience as a whole were affected by UI, and the women discussed both physical and psychological concerns. The main issues regarding sexuality included concerns related to relationships, frustrations with limited sexual activities and the difficulty of being sexually satisfied, the number of unanswered questions and concerns, and a fear of being hurt or injured while participating in sexual activities. The main concerns regarding UI were embarrassment, the work and inconvenience involved with the clean-up of UI, bladder infections, the lack of accessible washrooms, and the negative effects of UI medications. When examining sexuality and UI together, the major issues were the constant comparison to the way things were before SCI, as well as the new concerns that the women did not have to worry about previously, worrying about how their partner would react if UI were to occur during sexual activity, and the impact of their own feelings toward UI on sexuality, a connection between pleasurable sexual sensations and UI as well as difficulty differentiating between the sensation of UI with the sensation of UI, dealing with infected urine during sexual activity, having to discuss UI with a new potential sexual partner, and a fear of rejection. Other identified issues included those related to body image, a lack of resources, Doctors who were inadequately educated regarding SCI, and issues related to both having and raising children. There is a significant shortage of information available for women with SCI to use as a resource regarding sexual function in general, and sexual function as it relates to UI. It is necessary that future work focus on creating resources to assist in this area, and that the dissemination of those resources becomes both appropriate and effective. Addressing sexual function and UI which are among the top concerns for this population has the opportunity to greatly improve quality of life (QOL) for these individuals.

Blood, Sweat and Cheers: Absurdist Crime Films and Contemporary Society

Within the crime film tradition there is a plethora of sub-genres all of which relate to crime and its consequences. However, directors Joel and Ethan Coen, Quentin Tarantino and David Lynch, all of whom create plots around crime and criminality, have been difficult to pin down and attribute to any given sub-genre. This thesis demonstrates that an absurdist philosophy can be used to effectively examine the content of the previously mentioned filmmakers. Through an analysis of these filmmakers and their better known works compelling evidence is revealed suggesting that these filmmakers may all belong to the emerging crime film sub-genre known as absurdist crime films.

All of My Blood is Red: Contemporary Metis Visual Culture and Identity

This thesis explores notions of contemporary Metis identity through the lens of visual culture, as articulated in the works of three visual artists of Metis ancestry. I discuss the complexities of being Metis with reference to specific art works by Christi Belcourt, David Garneau and Rosalie Favell. In addition to a visual culture analysis of these three Metis artists, I supplement my discussion of Metis identity with a selection of autoethnographic explorations of my identity as a Metis woman through out this thesis. The self-reflexive aspect of this work documents the ways in which my understanding of myself as a Metis woman have been deepened and reworked in the process of conducting this research, while also offering an expanded conception of contemporary Metis culture. I present this work as an important point of departure for giving a greater presence to contemporary Metis visual culture across Canada:

Effect of increased milk intake combined with endurance exercise training on body composition, blood-lipids and inflammatory markers in overweight young males

Consuming low-fat milk (LFM) after resistance training leads to improvements in body composition. Habitual aerobic exercise and dairy intake are relatively easy lifestyle modifications that could benefit a population at risk for becoming obese. Thus, the purpose of this study was to investigate combining increased LFM intake with endurance exercise on body composition, blood-lipid profile and metabolic markers. 40 young males were randomized into four groups: one ingesting 750mL LFM immediately post-exercise, the other 6hrs post-exercise; and two isocaloric carbohydrate groups ingesting at the two different times. Participants completed a 12 week endurance-training program (cycling 1 hour/day at ~60%VO2peak, 5 days/week). 23 participants completed the study. Increases in lean mass (p < 0.05), and decreases in anti-inflammatory marker adiponectin (p < 0.05) were seen in all groups. No other significant changes were observed. Future analyses should focus on longer duration exercise and include a larger sample.

Exploring Body-Related Experiences among Individuals with Spinal Cord Injury

Using modified constructivist grounded theory, the purpose of the present study was to explore body-related experiences, specifically body image, in people with spinal cord injury. A total of nine participants (five women, four men) who had a broad range of body image experiences (from very negative to very positive) were interviewed. Most participants explained experiencing a fluctuating body image that varied from day-to-day. Negative body image experiences were represented by appearance, weight concerns, and function with all body image experiences encompassed by self-presentational concerns and tactics (an unanticipated finding). Positive body image was represented by acceptance, appreciation and gratitude of the body. Interestingly, negative body image experiences were not found to be represented by the opposite of positive body image experiences as they were each distinct. These findings have direct implications for medical professionals in hospital and rehabilitation settings to understand the importance of body image after spinal cord injury.

The role of microRNAs and retinoid signaling during spinal cord regeneration in the adult newt.

The molecular events after spinal cord injury that lead to the establishment of a permissive environment and epimorphic regeneration remain unclear. Two molecular pathway regulators that may converge to create a spinal cord regeneration-permissive environment in the urodele are retinoic acid (RA) and microRNAs (miRNAs). Recent evidence suggests that RARβ-mediated signaling is necessary for tail and caudal spinal cord regeneration in the adult newt. MicroRNAs are attractive candidates as mediators of retinoid signaling during regeneration, as their pleiotropic effects are vital in situations where global changes in gene expression are required. Thus, the overall aim of this thesis was to determine if miRNAs are involved in tail and caudal spinal cord regeneration in the adult newt, and if they act as regulators and/or effectors of retinoid signaling during this process. I have demonstrated here, for the first time, that multiple miRNAs are dysregulated in response to spinal cord injury in the adult newt, as well as in response to inhibition of retinoid signaling. Two of these miRNAs, miR-133a and miR-1, appear to target RARβ2 transcripts both in vivo and in vitro. Inhibition of RA signaling via RARβ with a selective antagonist, LE135, alters the pattern of expression of these miRNAs, which leads to an inhibition of tail regeneration. These data are indicative of a negative feed back loop, albeit potentially an indirect one. I also aimed to examine which miRNAs are affected by inhibiting RA synthesis during regeneration, and provided a long list of miRNAs that are dysregulated. These data provide the foundation for future studies on the putative roles of these miRNAs, as well as their function in retinoid signaling. Overall, these studies provide the first evidence for a role for miRNAs as mediators of retinoid signaling during caudal spinal cord regeneration in any system.