Recent Submissions

  • Impacts of the COVID-19 Pandemic on Body Mass, Physical Activity and Nutrition in Canadian Post-Secondary Students

    Bell, Madison; Applied Health Sciences Program
    This study examined changes in body mass, physical activity, and dietary intake and habits in Canadian university students during the first (March – September 2020) and second (October 2020 – March 2021) lockdown/restrictions of the COVID-19 pandemic. Two observational, self-reported recall surveys were conducted online; in September 2020 (T1) and March 2021 (T2). Five hundred ten (99 males, 411 females) students completed the survey at T1 and 135 of them also completed the survey at T2. The surveys included demographic information (age, sex, living arrangements, activity level, etc.), body mass and height, and a series of standardized questionnaires on eating habits and behaviours, as well as energy, macronutrient, and micronutrient intake. Body mass and body mass index increased in both males and females. Body mass increased on average by 0.91 kg, t(132) = -2.7, p = 0.008, 95%CI = [0.24, 1.58]. Importantly, a significant change was shown that between T1 and T2 with a greater number of participants identified as overweight (19.8% to 24.4%) than normal weight (61.7% to 54.8%). Body mass change was not associated with changes in physical activity and dietary intake. Females were more likely to decrease At Home Workouts compared to males with no other significant changes detected for type of physical activity in either T1 or T2. Energy intake significantly decreased by ~200 kcals/d. Diet quality also changed in both sexes characterized by negative changes in in both macro and micronutrients. Restrictive eating behaviours were found to increase significantly in females and were more frequent in those with eating disorders. Therefore, modest weight gain did occur during the pandemic in Canadian university students despite the insignificant changes reported in physical activity and the decrease in overall dietary intake, which can be possibly attributed to the changes in diet quality and dietary behaviours.
  • The Big Five Personality Traits and Choking Susceptibility

    Thiessen, Burgandy; Applied Health Sciences Program
    Choking susceptibility is the likelihood or potential of an individual choking under pressure (Mesagno et al., 2012). Choking susceptibility may be influenced by personality traits. The purpose of this study was to examine the differences between the Big Five personality traits on choking susceptible and choking non-susceptible individuals. A protocol developed by Mesagno et al. (e.g., 2008; 2009), comprised of a self-consciousness scale, sport anxiety scale, and coping style scale, was used to measure choking susceptibility. Personality traits were measured using the Big Five Inventory-10. A total of 60 post-secondary students were analysed in this study; 30 were choking susceptible and 30 were choking non-susceptible. A MANOVA showed a significant effect of the personality traits on choking susceptibility. Separate univariate tests on the outcome variables (i.e., neuroticism, openness, extraversion, agreeableness, and conscientiousness) revealed a significant effect for neuroticism. Additionally, a discriminant function analysis further showed that neuroticism contributed the most to choking susceptibility compared to the other four personality traits. According to the current study, individuals higher in neuroticism are more choking susceptible than those lower in neuroticism. Therefore, individuals who are neurotic may benefit from interventions designed for their personality to combat the likelihood of choking under pressure. This study is the first to use Mesagno’s choking susceptibility protocol outside of sport.
  • Investigation of the Anti-Proliferative and Pro-Apoptotic Effects of Rosemary (Rosmarinus officinalis) Extract on Androgen Independent Prostate Cancer Cells

    Termini, Deborah; Applied Health Sciences Program
    Prostatic carcinoma is established as the third most prevalent cancer type in the worldwide population and accounts for 21% of new cancer cases in Canadian men. Prostate cancer can be categorized as androgen dependent or androgen independent, indicative of the tumor’s ability to respond to testosterone stimulation. Currently available treatments include prostatectomy, radiation therapy, androgen deprivation therapy, immunotherapy, and chemotherapy. Despite all of these treatment options, biochemical reoccurrence, and progression into more advanced stages (castration-resistant prostate cancer- CRPC) is often seen, indicating a need for novel therapeutics that specifically and efficiently target the dysregulated mechanisms in prostate cancer. In some studies, rosemary extract and its polyphenolic constituents have been shown to have anticancer properties, but the exact effects and mechanisms of action are not known. The purpose of the present study was to investigate the potential pro-apoptotic and anti-proliferative effects of rosemary (Rosmarinus officinalis) extract (RE) on prostate cancer cells. PC-3 and 22Rv1 prostate cancer cells, representative in vitro models of androgen independent prostate cancer, as well as the PNT1A non-cancerous prostate epithelial cells were treated with RE and docetaxel (established prostate cancer chemotherapeutic drug) for the purpose of assessing the extent of survival and proliferation, and to investigate changes in expression of key proteins involved in apoptotic and survival signalling cascades. In our studies, RE inhibited the proliferation (IC50: 26 μg/mL; 70 μg/mL) and colony formation efficiency (IC50: 2.8 μg/mL; 4.8 μg/mL) of PC-3 and 22Rv1 prostate cancer cells, respectively, and enhanced cell death by stimulating apoptosis as shown by the increased levels of cleaved caspases 9, 7, 3, and PARP. Enhanced phosphorylation of ERK 1/2, paired with a notable increase in reactive oxygen species (ROS) were also observed in RE- treated PC-3 cells. In contrast, RE had no effect on the proliferation and survival of PNT1A normal epithelial cells, suggesting an action of RE promoting inhibition of prostate cancer cells while sparing non-cancerous epithelial cells.
  • The Influence of Posttetanic Potentiation on Neuromuscular Efficiency in Mouse Fast Twitch Muscle at 25°C

    Laidlaw, Ryan; Applied Health Sciences Program
    Within skeletal muscle the release of calcium is responsible for the initiation of muscle contraction. In addition intracellular Ca2+ also induces the protein skeletal muscle myosin light-chain kinase (skMLCK) to phosphorylate the regulatory light chain (RLC) of fast myosin isoforms. For a short time following RLC-phosphorylation a potentiated state is induced within muscle fibres in which force generation and other contraction dynamics are augmented. The intent of our study was to examine the effect of tetanic stimulation (>100Hz) induced potentiation on the efficiency of neuromuscular contraction (Work output: # of Pulses). Concentric contractions were used in which muscles shortened 1.10 -> 0.90 Lo, at ~70% maximal shortening velocity (Vmax). The fast twitch extensor digitorum longus muscles were excised and mounted in vitro (25oC) to examine the effect of NME on whole muscle function. Unique to our lab were the use of skMLCK-/- mice which are unable to phosphorylate their myosin-RLC, and thus display no magnitude of posttetanic potentiation. These models were used as a negative control for potentiation compared to the wild type EDL. NME was tested during series of submaximal tetani at five frequencies (10, 25, 40, 55, 80 Hz) before and after muscles were exposed to the conditioning stimulus (4 x 400 msec, 100 Hz, over 10 seconds). Neuromuscular efficiency was found to be increased at all frequencies for both wild type (P<0.001) and skMLCK-/- (P<0.002) genotypes following the CS (n=12). NME potentiation was significantly impacted by the expression of skMLCK and test frequency. At optimal frequency wild type EDLs displayed a 92% increased relative NME compared to the 33% seen in the skMLCK-/- genotype showing the importance of RLC-phosphorylation to contractile enhancement. Work values preceding the CS were not significantly different at any frequency in either genotype (P = 0.236). The presence of RLC phosphorylation is physiologically significant in enhancing force output as well as improving neuromuscular efficiency following PTP.
  • The Effect of Muscle Length on Post-Tetanic Potentiation of skMLCK-/- and C57BL/6 Mouse EDL Muscles

    Angelidis, Angelos; Applied Health Sciences Program
    Post-tetanic potentiation of force in fast skeletal muscle is inversely related to muscle or sarcomere length, diminishing at longer lengths. This relationship has been mainly attributed to the structural effects of the primary mechanism of potentiation, phosphorylation of the regulatory light chain (RLC) of myosin, which is catalyzed by skeletal myosin light chain kinase (skMLCK). The purpose of this thesis was to compare the relationship between isometric twitch force potentiation and muscle or sarcomere length in fast twitch extensor digitorum longus (EDL) muscles from wildtype and skMLCK-/- mice. It was hypothesized that in addition to reduced potentiation, skMLCK-/- muscles without the ability to phosphorylate the RLC would also display an altered length-dependence of potentiation compared to wildtype muscles with RLC phosphorylation. The main finding was that although twitch potentiation was greater in WT muscles at all lengths, the relationship between potentiation and muscle length was similar in both WT and skMLCK-/- muscles. This indicates that the length-dependence of potentiation cannot necessarily be attributed to RLC phosphorylation. Thus, additional mechanisms, possibly related to Ca2+ handling, thick filament mechanosensing and length-dependent activation may participate in the length-dependence of potentiation displayed by murine fast muscle models.
  • Menstrual Cycle Related Fluctuations in Circulating Markers of Bone Metabolism at Rest and in Response to Running in Eumenorrheic Females

    Guzman, Anne; Applied Health Sciences Program
    The aim of this study was to investigate potential fluctuations in bone metabolic markers across the menstrual cycle both at rest and after a 30-minute bout of vigorous-intensity running at 80% of �̇ O₂max. Resting and post-exercise (0, 30, 90 min) sclerostin (inhibitor of bone formation), parathyroid hormone (PTH, regulator of calcium homeostasis), carboxy-terminal cross-linking telopeptide of type I collagen (β-CTX, marker of bone resorption), and procollagen type 1 N propeptide (P1NP, marker of bone formation) were assessed in 10 young, eumenorrheic women (21.7 ± 3.2 years, 23.2 ± 3 kg. m2 ) during the mid- to late-follicular (FP: day 8.0 ± 1.4) and midluteal (LP: day 22.0 ± 2.5) phases of the menstrual cycle. Ovulation was determined using ovulation kits and daily measurement of oral body temperature upon awakening. Menstrual phase was subsequently confirmed by measurement of plasma estradiol and progesterone taken on study days, confirming an increase in both hormones during the mid-luteal phase. At rest, there were no significant differences in sclerostin (FP: 266.5 ± 48.6 pg·mL-1 ; LP: 296.0 ± 37.5 pg·mL-1 ; p=0.507), PTH (FP: 1.00 ± 0.22 pmol·L-1 ; LP: 0.71 ± 0.16 pmol·L-1 ; p=0.485), β-CTX (FP: 243.1± 52.7 ng·mL-1 ; LP: 202.4 ± 30.8 ng·mL-1 ; p=0.691), or P1NP (FP: 56.9 ± 11.30 ng·mL-1 ; LP: 64.30 ± 18.32 ng·mL-1 ; p=0.133) between menstrual cycle phases. As there were no main effects for menstrual phase and no significant interaction, post-exercise responses did not differ between menstrual phases for any of the markers. Significant main effects for time were found in sclerostin, PTH, β-CTX and P1NP. Specifically, sclerostin and PTH increased from pre- to immediately postexercise (+46% and +43%, respectively; p<0.0001), then returned to resting concentrations at 30 min post-exercise. P1NP also increased immediately post-exercise (+29%; p<0.0001), returning to resting concentrations at 30 min post-exercise. β-CTX decreased from pre- to immediately postexercise (-20%; p=0.004) and remained below its pre-exercise concentrations at 30 min postexercise (-12%; p=0.039) and 90 min post-exercise (-17%; p=0.002). These results demonstrate that sclerostin, PTH, β-CTX and P1NP do not differ at rest or in response to exercise across the menstrual cycle.
  • Kinematics and Muscle Activity of the Upper Extremity While Performing Cleaning Tasks

    Pipher, Zachary; Applied Health Sciences Program
    In Canada, occupations including janitors, caretakers, and building superintendents are the fourth most prevalent occupational group among men in the labour force, while cleaners are the 10th most prevalent occupational group among women (Statistics Canada, 2008). Cleaning tasks, typically labor-intensive, are characterized by a combination of static muscle loads (mainly involving bending and twisting of the back) and repetitive movements of the arms and hands requiring high physical exertion. Tasks such as lifting, mopping, and vacuuming often involve awkward postures with both dynamic and static muscular activities. These types of prolonged static and repetitive muscle activities cause muscle fatigue and may lead to musculoskeletal disorders. Therefore, the purpose of this study was to examine the effects of custodial cleaning tasks on upper extremity muscle activity and to assess changes in kinematics throughout the duration of a shift. Ten custodians employed at Brock University performed six cleaning tasks during two different sessions (pre-shift and post-shift). Kinematics of the upper extremity were collected, and muscle activity was recorded from 8 upper extremity muscles. Our results showed no significant changes in mean joint angles or joint range of motion pre-shift to post-shift. However, significant changes were observed in mean and peak EMG amplitudes as a result of time. Higher muscle activity was observed in the upper trapezius and FDS while lower muscle activity was found in the anterior deltoid, posterior deltoid, and EDC post-shift compared to pre-shift. This suggests that custodians use different muscular strategies to maintain task performance over the duration of a work shift. This may imply they are experiencing fatigue due to insufficient rest. This work acts as a stepping-stone into future investigations of custodial work and the adaptations over time.
  • A Principal Component Analysis Comparing Forward Skating Strides Pre-Post Skate Treadmill Training in Youth Hockey Players

    Iantomasi, Vincent; Applied Health Sciences Program
    The purpose of the study was to explore temporal and phasic waveform patterns within kinematic data, obtained from forward skating strides, pre-post skate treadmill training in youth (U-11), male hockey players to investigate changes in kinematics. Continuous joint angle (deg) and angular velocity (deg/s) stride data for the trunk, hip, and knee were determined, time normalized, and averaged. PCA results suggested that most of the pre-post variance in skating mechanics could be explained through an increase in joint angle (deg) and angular velocity (deg/s) magnitudes during the propulsive and recovery phases of the stride cycle. Single component reconstruction (SCR) facilitated visual representation and interpretation of kinematic differences by isolating variances within each principal component and reconstructing lower (5th percentile) and upper (95th percentile) waveforms based on the respective scalar weight factor of PC scores. Post-training, SCR suggested patterns of increased trunk extension throughout the stride cycle, increased hip and knee extension during propulsion, and increased hip and knee flexion during recovery. Statistical parametric mapping (SPM) statistically analysed continuous data points across two waveforms. SPM revealed significant differences in pre-post trunk flexion and extension magnitudes from the early glide phase to propulsion onset ([p=0.0023], ~0-20% stride cycle) and from late propulsion to weight acceptance ([p=0.0001], ~40-80% stride cycle). Differences in pre-post hip and knee measures were non-significant (p>0.05). PCA, SCR and SPM analyses have the potential to contribute to our understanding of biomechanical training adaptations in stride mechanics in youth ice hockey players.
  • Examination of chronic BDNF treatment and endurance training on skeletal muscle adaptations

    Brown, Alexander David; Applied Health Sciences Program
    Brain-derived neurotrophic factor (BDNF) was recently described as a contraction-induced protein, produced by muscle and released into circulation, having autocrine and endocrine actions. Our understanding of BDNFs role in skeletal muscle is limited; however, it may play a role in how muscle adapts to exercise. Thus far it is known that BDNF expression varies between skeletal muscle fiber types but is predominately found in oxidative muscle. Acute exercise bouts increase circulating and skeletal muscle BDNF, and BDNF treatment of isolated muscles increases fat oxidation through activation of AMPK. The effects of endurance training and BDNF administration on these parameters have yet to be examined. This study's purpose was to compare chronic subcutaneous BDNF treatment with endurance training in mice. A secondary purpose was to deterimine if BDNF treatment could enhance endurance training adpatations. Male C57BL6 mice were randomly assigned to one of four groups (n=12/group): 1) control (CON); 2) endurance training (ET; treadmill running 1hour/day, 5days/wk); 3) BDNF (BDNF; 0.5 mg/kg·bw, 5days/wk); 4) endurance training and BDNF (ET+BDNF) for 8 weeks. Results showed a main effect of BDNF on reducing body mass (p<0.05) and food intake (p<0.05). The treadmill test to exhaustion demonstrated a main effect of BDNF (p<0.01) and ET (p<0.0001) on increasing exercise capacity (p<0.05), further ET+BDNF increased time to exhaustion compared to the ET group (p<0.001). In vitro contractile assessment of the EDL revealed BDNF treatment resulted in similar increases in the max rate of relaxation as ET alone. EDL force-frequency analysis showed ET+BDNF produced higher force than CON and BDNF (p<0.05). No effect of BDNF on soleus contractile properties was observed. BDNF increased EDL COXIV and CS content (p=0.06), however not to the same extent as ET (p<0.05). No effect of BDNF on mitochondrial markers was observed in the soleus. The current study provides novel data regarding the effect of chronic BDNF treatment and exercise on appetite regulation, exercise capacity, and mitochondrial markers in a healthy mouse model. These results demonstrate that BDNF may contribute to skeletal muscle adaptations observed with endurance training. Further work is needed to determine if BDNF is required for these adaptations.
  • Changes in Periodontal Status after Pandemic-Related Interruptions to Care in a Fragile Cohort

    Young, Hannah; Applied Health Sciences Program
    Sanative therapy (ST) can be a highly effective first-line therapy for periodontal disease. However, even after successful ST, patients require life-long periodontal maintenance therapy (PMT) to maintain their periodontal health. As a result of the COVID-19 global pandemic, stay-at-home orders and other public health measures resulted in many patients missing or delaying their regularly scheduled PMT appointments. The primary objective of this study was to determine, at 5 to 10 years post-ST, if patients who delayed their appointments as a result of COVID-19 experienced significant changes in periodontal probing depth (PPD), bleeding on probing (BOP), and plaque index (PI) compared to patients without appointment delays. Additionally, lifestyle factors such as dietary intake, physical activity, and oral hygiene behaviors were hypothesized to have been altered because of the COVID-19 pandemic, and interview questions were used to capture these changes. The study was completed at a private periodontal clinic. Patient medical and dental history data was collected retrospectively from patient charts. Due to challenges with recruitment, a subset of the required sample size was studied with findings providing pilot data for a larger future study. Study participants (n = 12) were asked to complete two different physical activity questionnaires, a 24-hour dietary recall, and a supplement and tea questionnaire online. Furthermore, a short virtual interview was used to ask participants how they felt COVID-19 impacted several lifestyle factors. At 5 to 10 years post-ST, a short delay in PMT appointments of 2 – 6 months did not significantly affect PPD, BOP and PI. Most participants reported changes to physical activity (80%) and diet (80%), but no changes to oral hygiene behaviors (90%). Overall, physical activity, diet, and body mass index data in the study sample closely aligned with findings from larger studies that have assessed these aspects in the Canadian population. This pilot study should be used to design future studies aimed at investigating the relationship between periodontal health and behavioral changes resulting from the COVID-19 pandemic.
  • Do weight status and weight perception predict academic acheivement in adolescents? A longitudinal analysis of the COMPASS study.

    Livermore, Maram; Applied Health Sciences Program
    Abstract Background: Recent evidence suggests perceptions of overweight account for the psychosocial consequences typically associated with obesity. Previous research indicates the presence of an obesity achievement gap, yet limited research has explored weight perception in association with academic achievement. Previous studies have focused on grades and degree attainment, without consideration of student aspirations and perceived support and ability to achieve higher levels of education. This thesis examined how Body Mass Index (BMI) classification and weight perception relate to academic performance and postsecondary aspirations and expectations in a large cohort of Canadian adolescents. Additionally, the interaction between BMI status and perceptions of weight was examined in relation to academic achievement outcomes. Methods: Two-year survey data from 25,673 grade 9-12 students attending the 122 Canadian schools that participated in Year 6 (2017/2018) and Year 7 (2018/2019) of the COMPASS study were used. Generalized estimating equation models were used to examine associations between students’ BMI classification and weight perception and their math and English/French course grades and post-secondary academic aspirations and expectations. All models were stratified by gender and adjusted for sociodemographic variables and school clustering. Results: Boys and girls with BMI of obesity and missing BMI classification reported lower grades and post-secondary aspirations and expectations when compared to those with Normal BMI. Similarly, boys and girls with overweight BMI reported lower math and language grades than those with Normal-weight BMIs. Relative to their peers with normal-weight BMI and “about right” perceptions, those with overweight perceptions and BMI of overweight/obesity reported lower academic grades and post-secondary aspirations and expectations. There was evidence of an additive effect for girls and boys with overweight perceptions and BMI of overweight/obesity on academic outcomes. About right perceptions of weight were protective against lower math grades for boys and girls with overweight/obesity BMI. Results varied by gender and across academic outcomes. Conclusions: Overall, this thesis demonstrates that an obesity achievement gap remains when controlling for students’ perceptions of their weight. Perceptions of overweight had a detrimental effect on academic performance and aspirations/expectations for students with BMI classifications of overweight and obesity, as well as grade outcomes for those with BMI of normal-weight. Results suggest that barriers to academic success exist for students with larger bodies. Future studies should explore the role of internalized and externalized weight bias.
  • Low-dose lithium supplementation and SERCA uncoupling in C2C12 cells and murine skeletal muscle.

    Geromella, Mia Sara; Applied Health Sciences Program
    Adaptive thermogenesis is a cellular process that accelerates energy expenditure while increasing heat production in response to prolonged cold exposure or caloric excess. The prevalence of obesity along with its comorbidities is continually rising. Obesity is a result of energy intake superseding energy expenditure, however, a balance between energy intake versus energy expenditure is key in weight maintenance. Therefore, enhancing adaptive thermogenesis may be relevant in combatting diet-induced obesity. Skeletal muscle via sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) uncoupling and brown/beige adipose via mitochondrial uncoupling are the two sites for adaptive thermogenesis in mammals. Recent evidence has shown that glycogen synthase kinase 3 (GSK3) negatively regulates adipose-based thermogenesis by repressing uncoupling protein-1 expression in brown adipocytes. However, to our knowledge, no studies have examined whether GSK3 also negatively regulates muscle-based thermogenesis via SERCA uncoupling. The SERCA pump catalyzes the active transport of 2 Ca2+ ions into the sarcoplasmic reticulum per 1 ATP hydrolyzed under optimal conditions. Sarcolipin (SLN), an uncoupler of SERCA makes Ca2+ transport less efficient by reducing SERCA coupling ratio. The objective of this thesis was to determine whether GSK3 inhibition with low dose lithium (Li) supplementation can increase SLN expression and promote SERCA uncoupling in both C2C12 cells and in murine soleus muscle. Our results show that in C2C12 cells, 0.5mM LiCl promotes GSK3 inhibition and SERCA uncoupling via an increase in ryanodine receptor (RYR) but not SLN. In contrast, soleus muscles from chow-fed and lithium supplemented mice did not result in any notable changes in SERCA coupling ratio or the content of SERCA associated proteins. We next determined whether this would differ under an added stress of a high-fat diet. Our results show that soleus homogenates of HFD+Li supplemented mice have significant reductions in SERCA coupling ratio compared with HFD alone, which was presumably due to an increase in SERCA uncoupling proteins SLN and NNAT. Altogether these data suggest the potential role of GSK3 inhibition via low dose lithium supplementation in activating muscle-based thermogenesis, particularly under the stress of a HFD.
  • The effect of increased dairy consumption during one week of intense training on serum bone markers of adolescent female athletes

    McKee, Katherine; Applied Health Sciences Program
    While high-impact exercise training typically has a positive effect on bone, intensified training during adolescence, the period of rapid growth and peak bone acquisition, could potentially have an opposite effect. Dairy foods contain bone-supporting nutrients (i.e., calcium) that are crucial to the structural integrity and strength of bone. In this study, 13 female adolescent soccer players (14.3 ± 1.3y) participated in a cross-over, randomized, double-blind trial examining the effects of Greek yogurt (GY) consumption on bone biomarkers during a one-week period of intensified training. The study took place over two intervention weeks, which consisted of a pre-training assessment day, 5-days of consecutive, intense soccer training and a post-training assessment day. Participants completed both the GY condition, and a carbohydrate isocaloric placebo control pudding condition (CHO) condition in random order, 4 weeks apart. Fasted, resting blood samples were collected in the morning at pre- and post-training sessions during each intervention condition. Total osteocalcin (tOC), undercarboxylated osteocalcin (unOC), carboxyl-terminal telopeptide of type 1 collagen (CTX), osteoprotegerin (OPG), and receptor activator nuclear factor kappa-β ligand (RANKL) were measured in serum. Results showed no significant effects for time (from pre- to post-training) and condition, and no interaction in tOC, CTX, OPG, RANKL and OPG/RANKL ratio. There was an interaction (p=0.011) for unOC, which decreased significantly at the end of the intense training period in the GY condition, but not in the CHO condition (-26% vs -3%, respectively). Relative unOC, expressed as a percentage of tOC, also reduced post-training (-16%), but with no differences between intervention conditions. These findings suggest that high-impact intense training had no direct catabolic impact on bone metabolism, at least in the short-term, and thus, GY added no benefit beyond that of the isocaloric CHO control pudding.
  • Inulin Supplementation to Support Periodontal Health

    Zanatta, Carly; Zanatta, Carly; Applied Health Sciences Program
    Periodontal disease is a chronic state of inflammation that can destroy the supporting tissues around the teeth, leading to the resorption of alveolar bone. The initial strategy for treating periodontal disease is non-surgical sanative therapy (ST). Periodontal disease can also induce dysbiosis in the gut microbiota and contribute to low-grade inflammation. Prebiotic fibres, such as inulin, can selectively alter the intestinal microbiota and support homeostasis by improving gut barrier function, preventing systemic inflammation which may help local inflammation in the periodontal tissues. Providing an inulin supplement may benefit periodontal health while providing insight into the complex relationship between periodontal disease and the gut microbiota. The primary objective is to determine if a daily 10 g dose of inulin for 14 weeks is more effective than the placebo at improving clinical periodontal outcomes including probing depth (PD) and bleeding on probing (BOP). Secondary objectives include determining the effects of inulin supplementation pre and post ST on salivary markers of inflammation and periodontal-associated pathogens, as these outcomes reflect more rapid changes than clinical periodontal outcomes. This thesis has involved the design and registration of a single-center, randomized, double-blind, placebo-controlled study design in which 170 participants who are receiving ST to manage periodontal disease will be randomized to the intervention (inulin) or placebo (maltodextrin) group. The intervention period will begin 4 weeks before ST through to their follow up appointment at 10 weeks post ST. Clinical outcomes of periodontal disease including number of sites with PD ≥ 4 mm and the absence of BOP will be measured at baseline and post ST. Salivary markers of inflammation (interleukin-1beta, interleukin-6, c-reactive protein and matrix metalloproteinase-8), periodontal-associated pathogens (Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Aggregatibacter actinomycetemcomitans), body mass index (BMI) and diet assessments will be measured at baseline, pre ST and post ST. Inulin is expected to enhance the positive effect of ST on the management of periodontal disease. The results of the study results will help to provide guidance regarding the use of prebiotics prior to and as a supportive adjunct to ST for periodontal health.
  • Characterizing RyR and SERCA function in the C57 and D2 mdx mouse models of Duchenne Muscular Dystrophy

    Cleverdon, Riley; Applied Health Sciences Program
    Duchenne Muscular Dystrophy (DMD) is a male-affected muscle wasting disease caused by the complete loss of the sarcolemmal protein dystrophin. No cure exists and patients typically succumb to cardiorespiratory issues in the third or fourth decade of life. Dystrophin loss also leads to dysfunction in other pathways; including impaired sarcoplasmic reticulum (SR) calcium (Ca2+) handling, further perpetuating the disease. This thesis examined potential differences in SR Ca2+ handling in two mouse models of DMD. The D2.B10-Dmdmdx/J (D2 mdx) mouse has emerged as a more pathologically representative model of DMD than the C57BL/10ScSn-Dmdmdx/J (C57 mdx) mouse model, showing greater muscle weakness, wasting and earlier disease onset. However, SR Ca2+ has not yet been characterized in the D2 mdx mouse. Thus, the aim of this study was to compare SR Ca2+ handling in the D2 mdx and C57 mdx mice. Using age-matched (9-10 week-old) mice, we found that D2 mdx mice had less mass, smaller gastrocnemius muscles, and were less ambulant. The D2 mdx mice had significantly higher energy expenditure and respiratory exchange ratio compared with the D2 WT mice. Two separate SR Ca2+ uptake assays revealed that D2 mdx mice have less Ca2+ uptake and leak, and higher starting myoplasmic Ca2+. SERCA activity (ATP hydrolysis) was lower in D2 mdx mice while higher in C57 mdx mice. These dramatic impairments in SR Ca2+ handling were not attributed to differences in SERCA isoform content or changes in its regulator, sarcolipin. However, under reducing conditions, protein nitration and nitrosylation content were significantly higher in D2 mdx gastrocnemius muscles. Further, pre-treatment with dithiothreiotol (DTT) did not improve SR Ca2+ handling in these muscles, suggestive of irreversible reactive oxygen/nitrogen post-translational modifications. Finally, calpain proteolytic activity was examined to determine the consequence of the impaired SR Ca2+ handling in the D2 mdx mouse. While D2 WT mice already had higher levels of calpain activity, the D2 mdx mouse had significantly higher calpain activity vs the C57 mdx mouse. Altogether, the results from this thesis suggest that impaired SR Ca2+ handling may be partially responsible for more severe pathology found in the D2 mdx mice.
  • The perception of mental toughness of student-athletes in their academic and sports domains

    Waters, Liam; Applied Health Sciences Program
    The purpose of this study was to investigate university student-athletes’ perceptions of mental toughness in both their sport and academic domains. This study took a general qualitative approach through a constructivist lens, to allow for student-athletes’ perceptions to shape the understanding of mental toughness. There were a total of 10 participants (3 male and 7 female student-athletes) interviewed from a variety of sports and academics programs. Thematic analysis was used to identify four main themes: the dynamic nature of mental toughness, outcomes of mental toughness, resilience, and relationships. Findings highlighted similarities and differences between sports and academics, that allow for a better understanding of mental toughness in general, specifically amongst this demographic. The theme “The dynamic nature of mental toughness” showed that mental toughness fluctuated within different environmental settings or with varying performance outcomes, but in general it improved over time. Outcomes of mental toughness refer to factors such as confidence that resulted when participants experienced high levels of mental toughness, and also included the pursuit and embrace of a challenge to compete at peak performance, staying consistent, and staying focused on the task. Resilience was mutually understood as an essential characteristic of mental toughness within both sports and academics, and was more pronounced amongst student-athletes when their mental toughness state was high. The theme of relationships was a unique finding that showed how personal and professional relationships contribute to mental toughness differently within sports compared to academics. Forming a personal relationship with a teammate/classmate outside of the direct sport/academic setting helped athletes with their mental toughness. Additionally, it helped form a stronger professional relationship within the respective domains as well, aiding their performance. Across all themes, mental toughness was more prominent in sports than academics, where student-athletes generally described mental toughness as playing a crucial role in their academics. In addition, results showed support for the unidimensional nature of mental toughness through its general applicability described by participants in both domains without restriction of different dimensions. Therefore, the findings of this study indicate that mental toughness is a crucial psychological resource for student-athletes within both sports and academics.
  • APP Processing: A Biochemical Competition Influenced by Exercise-Induced Signalling Mediators

    Marko, Daniel; Applied Health Sciences Program
    In our aging society neurodegenerative diseases such as Alzheimer’s disease (AD) are becoming more prevalent. One specific neuropathological hallmark of this disease is excessive accumulation of amyloid-β (Aβ) peptides, which can aggregate to form the plaques commonly associated with this disease. These plaques are often observed well before symptoms of AD develop. Therefore, it is important to find ways to regulate the pathways involved in the production of these peptides. Evidence indicates that exercise has the capacity to reduce Aβ peptide production in the brain. Exercise promotes the release of many different signalling mediators from various tissues and organs in the body. These exercise-induced signalling mediators could be the driving force behind some of the beneficial effects seen in the brain with exercise. The purpose of this study was to examine if post-exercise serum and the factors it contains can alter neuronal APP processing. Human SH-SY5Y neuronal cells were differentiated with retinoic acid for 5 days and treated with 10% pre- or post-exercise serum for 30 minutes. Cells were collected for analysis of acute (30 minutes; n=6) or adaptive (24 hours post-treatment; n=6) responses. There were no statistical differences in ADAM10 and BACE1 mRNA or protein expression with post-exercise serum treatment at either time point. However, there was an increase in the ratio of sAPPα to sAPPβ protein content (p=0.05) after 30 minutes of post-exercise serum treatment. Additionally, 30 minutes of post-exercise serum treatment increased ADAM10 (p=0.01) and BACE1 (p=0.02) activity. These novel findings suggest that post-exercise serum modulates important enzymes involved in APP processing, potentially pushing the cascade towards the non-amyloidogenic arm.
  • Understanding the relationship between body image and menopause in South Asian Canadian women

    Dhillon, Taranjot Kaur; Applied Health Sciences Program
    Research regarding women’s body image during menopause is limited; few studies reflect the experiences of ethnic women, especially South Asian women living in Canada. Cultural differences play an important role in both body image and menopause experiences and may be particularly important to South Asian women, who often fear stigmatization and struggle with openly discussing health concerns. This study used interpretive phenomenological analysis, which focuses on understanding and interpreting the experiences of the participants, to explore the relationship between body image and the transition of menopause in South Asian Canadian women. Nine first generation South Asian immigrant Canadian women (aged 49-59 years), in perimenopause or postmenopause were recruited for semi-structured individual interviews. Overall, three themes were constructed: 1) Complexity and intertwining of body image and menopause experiences, which showed that although women understood body image as a multidimensional construct, their own body image focused on weight and appearance that was impacted by menopause and aging; 2) “It's just something we go through silently”: The challenges of body image and menopause experiences, which highlighted the lack personal support from family and South Asian community and the disconnected feeling from their bodies through the menopause transition; and 3) The push and pull of South Asian and Western cultures, which focused on conflicts between the two cultures and influence of the South Asian culture on beauty, body image, and aging. Results showed that participants often upheld Western body image ideals by equating positive body image practices and attitudes with these ideals, and this was often worsened by South Asian cultural norms. Additionally, women’s understanding of body image and menopause showed a gap between their personal understanding and research. Participants emphasized a lack of ethnically appropriate education for body image and menopause, suggesting there is a need for the implementation of culturally-appropriate and community-based interventions, and resources (e.g., workshops, seminars, support groups). Moreover, an underlying narrative of cultural conflict (Western vs South Asian cultures) and impact of the South Asian culture was evident. Therefore, further examination of the complexity and influence of the South Asian culture on body image and menopause experiences is required.
  • The Role of Dopamine on Central Neuromuscular Activation during Passive Hyperthermia

    Scholey, Aiden; Applied Health Sciences Program
    Acute methylphenidate (MPH) (dopamine reuptake inhibitor) ingestion improves cycling time trial performance and power output in hot conditions (30 C), while also allowing for tolerance of higher core temperatures. However, the mechanisms for why this occurs have not been isolated. One potential explanation for this ergogenic benefit is that MPH intake was enhancing neuromuscular activation. Thus, this research project examined the influence of MPH on neuromuscular activation during hyperthermia. Participants ingested either placebo (PLA; 20mg) or MPH (Ritalin; 20mg) 1 hour prior to a passive heating protocol. 6 participants were passively heated until volitional cessation, or after 3 hours of heating had passed. Neuromuscular responses, as indicated by maximal voluntary contraction (MVC) force, and voluntary activation (VA) percentage were assessed prior to drug ingestion, 1 hour after MPH wash-in, throughout the heating protocol and at cessation of heating. A primary non-significant finding of this research project was that participants reached higher rectal temperatures (Tre) by ~0.3 C in trials where they ingested MPH (p = 0.065). This effect occurred in absence of any differences in thermal comfort or sensation ratings or heating durations. However, while MPH improves thermal tolerance, it was not able to attenuate the decreases in MVC force and VA that occurred during passive heating. Therefore, the aforementioned ergogenic benefits that MPH has in hot conditions are not occurring as a result of enhanced neuromuscular activation.
  • The effects of postural threat on sample entropy

    Fischer, Olivia; Applied Health Sciences Program
    The objectives of this thesis were to 1) explore the effects of postural threat on sample entropy, a measure interpreted to reflect the attentional investment in postural control, and to 2) examine the relationships between threat-related changes in physiological arousal, perceived anxiety, attention focus, conventional postural control measures, and sample entropy. A secondary data analysis was conducted on a combined data set derived from two published studies; each study used the postural perturbation threat model which allowed for a comparison between No Threat and Threat conditions. Young adults (N = 105) stood without (No Threat) and with (Threat) the expectation of receiving a temporally and directionally unpredictable support surface translation in the forward or backward direction. Mean electrodermal activity and anterior-posterior centre of pressure mean position, root mean square, mean power frequency, power within low (0–0.05 Hz), medium (0.5–1.8 Hz), and high frequency (1.8–5 Hz) components, and sample entropy were calculated for each trial. Anxiety and attention focus to movement processes, task objectives, threat-related stimuli, self-regulatory strategies, and task-irrelevant information were rated after each trial. The results of the thesis showed that postural threat had a significant effect on sample entropy; higher values were reported in the Threat compared to No Threat condition. However, threat-related changes in physiological arousal, perceived anxiety, and attention focus were not significantly related to changes in sample entropy. Threat-related changes in sample entropy were related to changes in sway amplitude and frequency. The results of this thesis suggest a shift to a more automatic control of posture when threatened despite evidence of increased attention to postural control.

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