• Investigating the Neuromuscular Response to Sudden Wrist Perturbations

      Forman, Garrick; Applied Health Sciences Program
      The purpose of this work was to evaluate changes in forearm muscle activity and co-contraction caused by sudden wrist perturbations during a dynamic wrist tracking task using a haptic wrist robot. Surface electromyography was recorded from eight muscles of the upper-limb. Participants were seated with their forearm placed on an armrest, grasping the handle of a haptic wrist robot. Participants performed trials consisting of 17 repetitions of ±40° of wrist flexion/extension. During trials, participants received 3 perturbations. Perturbations varied based on condition: radial or ulnar direction, during flexion or extension, and with known or unknown timing. Co-contraction ratios for all muscle pairs illustrated significantly greater extensor activity across all experimental conditions. Expected (known) perturbations produced greater anticipatory muscle activity as well as greater task performance. While improving performance, this increase in anticipatory muscle activity may leave muscles susceptible to early-onset fatigue and chronic overuse injuries in the workplace.
    • Investigating the role of estrogen deprivation and diet-induced insulin resistance on markers of amyloid-β production and degradation in the brain

      Hayward, Grant; Applied Health Sciences Program
      Estrogen loss, which women experience during menopause, has recently been associated with increased amyloid-β (Aβ) peptides, a main feature of Alzheimer’s Disease (AD). Furthermore, diet-induced insulin resistance has also been shown to increase Aβ; however, whether this process is exacerbated with the loss of estrogen remains unknown. We aimed to investigate the effects of estrogen loss on amyloid production and degradation pathways, as well as markers of insulin signaling, glucose uptake and synaptic function, in an insulin resistant mouse model. To do this, female C57BL/6J mice received either bilateral ovariectomy, to simulate estrogen loss, (OVX; n=20) or remained intact (n=20) at 24 weeks of age. Mice were then placed on either a low or high fat diet (LFD; n=10 for OVX and intact, HFD; n=10 for OVX and intact) for 10 weeks to induce insulin intolerance. Prefrontal cortex and hippocampus tissues were then isolated and markers of amyloidogenesis, Aβ degradation, insulin signaling, glucose uptake, and synaptic function were examined. Independently, OVX led to increases in the amyloidogenic marker, sAPPβ. Furthermore, HFD combined with OVX, led to lower IDE protein content and activity in the prefrontal cortex, indicative of decreased Aβ degradation. Lastly, HFD with OVX led to exacerbated decreases in pGSK-3β /GSK, GLUT1, and Homer-1 (a postsynaptic marker) in the hippocampus, and GLUT3 in the prefrontal cortex. Data from this study provide evidence of a synergistic effect of systemic insulin resistance and estrogen loss in decreasing brain markers of Aβ degradation, insulin signaling, glucose uptake, and synaptic function. Furthermore, findings indicate how the loss of estrogen can promote the formation of amyloidogenic APP cleavage products, independent of diet-induced insulin resistance. These results ultimately contribute to our understanding of both estrogen-deprivation and insulin resistance on female brain health in relation to AD progression.
    • Investigation of Periodontal Outcomes After Sanative Therapy Among Patients With or Without Dry Mouth

      Sparrow, Taylor; Applied Health Sciences Program
      Untreated periodontal disease can have detrimental consequences on oral health. Consequences such as tooth loss can significantly affect an individual’s daily habits such as eating, speaking, and socializing. Sanative therapy (ST) followed by ongoing periodontal maintenance appointments is necessary to attenuate periodontal disease and prevent tooth loss. In addition to ST and periodontal maintenance appointments, saliva has an essential role in oral health. However, the relationship between salivary flow and periodontal outcomes, particularly in terms of low salivary production, has not been extensively investigated. The first objective was to determine if patients with dry mouth have similar probing depths as patients without dry mouth when receiving regular periodontal maintenance post-ST. The second objective was to determine if patients who alternate periodontal maintenance appointments between a general dental clinic and a periodontal specialty clinic have different probing depths than patients who solely have periodontal maintenance at a periodontal specialty clinic post-ST. Patients who had completed initial ST 1 to 5 years prior and continued with routine periodontal maintenance provided an unstimulated saliva sample and completed questionnaires assessing their symptoms of dry mouth. It was hypothesized that patients who have inadequate salivary flow exhibit worsened probing depths than patients who have adequate salivary output. However, periodontal health was maintained post-ST to present day for both groups. The second hypothesis was that patients who have periodontal maintenance performed solely at a periodontal specialty clinic have improved periodontal outcomes than those who alternate appointments 1 to 5 years post-ST There was a significant difference in probing depth between patients who do or do not alternate appointments (p < 0.05). Patients who do not alternate appointments had significantly greater probing depth than those who alternate. This may be due to the periodontist’s recommendation for patients of unstable periodontal health to be solely seen at specialty clinic.
    • Investigation of the anti-cancer effects of rosemary (Rosmarinus Officinalis L.) extract in human breast and prostate cancer cells

      Jaglanian, Alina; Applied Health Sciences Program
      Breast and prostate cancer are the most frequently diagnosed cancers in women and men respetively, in North America. Triple-negative breast cancer (TNBC) cells do not express estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (HER-2). TNBC accounts for 15% of all breast cancer cases, is aggressive in nature, and is characterized by resistance to chemo and radiotherapy thus, finding new approaches to inhibit it are urgently needed. Similarly, prostate cancer is typically characterized by the expression of androgen receptor (AR) and prostate-specific antigen (PSA). Prostate cancer that is AR positive can be treated with hormonal therapy. In contrast, AR negative prostate cancer is more aggressive and does not respond to hormone therapy, thus new approaches, including identifying specific signaling molecules that are overactivated and could be targeted, are required to effectively treat this subtype of prostate cancer. Rosemary extract (RE) has been shown to have anti-cancer properties in vitro and in vivo. However, limited evidence exists regarding its effect on triple-negative breast cancer and AR negative prostate cancer. In this study, we examined the effects of RE on triple-negative breast cancer cell (MDA-MB-231) and androgen insensitive prostate cancer cell (PC-3) proliferation, survival/apoptosis, and migration. In addition, we investigated the effect of RE treatment on key signaling molecules involved in cancer cell proliferation and survival.
    • Investigation of the Biological Effects of Rosemary (Rosmarinus Officinalis L.) Extract in Human Lung Cancer Cells

      Moore, Jessy; Applied Health Sciences Program
      Cancer cells display enhanced growth rates and a resistance to apoptosis. Lung cancer accounts for the most cancer related deaths and non-small cell lung cancer (NSCLC) represents an aggressive form of lung cancer, accounting for almost 80% of all lung cancer cases. The phytochemical rosemary extract (RE) has been reported to have anticancer effects in vitro and in vivo however, limited evidence exists regarding the effects of RE and its polyphenolic constituents carnosic acid (CA) and rosmarinic acid (RA) in lung cancer. The present study shows RE, CA and RA inhibit lung cancer cell proliferation and survival in various NSCLC cell lines and that CA and RA interact synergistically to inhibit cell proliferation. Moreover RE, CA and RA are capable of altering activation and/or expression of Akt, ERK and AMPK, signaling molecules which regulate cell proliferation and survival. RE shows potential as an anticancer agent and should be further investigated.
    • Investigation of the Expression of Glucose Transporter Proteins in Human Cancer Cells

      Barron, Carly; Applied Health Sciences Program (Brock University, 2012-08-15)
      Cancer cells are known to display increased glucose uptake and consumption. The glucose transporter (GLUT) proteins facilitate glucose uptake, however, their exact role in cancer metabolism remains unclear. The present study examined mRNA and protein expression of GLUT1, GLUT3, GLUT4 and GLUT12 in lung, breast and prostate cancer cells and corresponding noncancerous cells. Additionally, GLUT expression was determined in tumours from mice xenografted with human cancer cells. Differences in the mRNA and protein expression of GLUTs were found between cancerous and corresponding noncancerous cells. These findings demonstrate abundant expression of GLUT1 in cancer and highlight the importance of GLUT3 as it was expressed in several cancer cells and tumours. GLUT expression patterns in vitro were supported by the in vivo findings. The study of GLUT protein expression in cancer is important for understanding cancer metabolism and may lead to identification of biomarkers of cancer progression and development of target therapies.
    • Investigation of the Time Dependent Influence of Extracellular Osmotic Stress on Protein Turnover in Skeletal Muscle Cells

      McAlpine, Michael; Applied Health Sciences Program
      Acute alterations in cell volume can substantively modulate subsequent metabolism of substrates. However, how such alterations in skeletal muscle modulate protein metabolism is limited. The purpose of this study was to determine the time dependent influence of extracellular osmotic stress on protein turnover in skeletal muscle cells. L6 cells were incubated in hyperosmotic (HYPER; 425.3 ± 1.8mmol/kg), hypo-osmotic (HYPO; 235.4 ± 1.0mmol/kg) or control (CON; 333.5 ± 1.4mmol/kg) media for 4, 8, 12, or 24hrs. During the final 4hrs, incorporation of L-[ring-3,5-3H]-tyrosine was measured to estimate protein synthesis. Western blotting measured markers of protein synthesis and degradation. No differences were observed in any outcomes except p70S6K phosphorylation whereby HYPO was lower (p<0.05) than CON and HYPER; which remained similar except for a large increase at 8hrs for HYPER. These findings suggest that regardless of duration, extracellular osmotic stress does not significantly affect protein metabolism in L6 cells.
    • Investigative links between cognitive function and moderate-to-vigorous physical activity in elementary physical education

      Pirrie, A. Melissa.; Applied Health Sciences Program (Brock University, 2008-06-01)
      Research has noted both physical and psychosocial benefits when children participate in regular physical activity. Recent studies are indicating that there may also be academic benefits and that students may be more efficient learners with participation in physical activity. This study investigated the influence of acute moderate-to-vigorous physical activity on four cognitive functions: planning, attention, simultaneous processing, and successive processing. Three classes (59 students) were each tested twice using a balanced design (intervention, balance, and control groups). It was found that the intervention group had a large increase in planning abiHty (ES = 1.67) when compared to the balance (ES = .80) and control (ES = -.89) groups. On the three remaining cognitive functions, the intervention group showed effect sizes similar to that of the balance and control groups. These results indicate that improved planning after physical activity may playa role in improving student performance.
    • Left ventricular structure in children with developmental coordination disorder

      Chirico, Daniel; Applied Health Sciences Program (Brock University, 2011-03-08)
      Developmental coordination disorder (p-DCD) is a neuro-developmental disorder featuring impairment in developing motor coordination. This study examined left ventricular mass (LVM) in children with p-DCD (n=63) and controls (n=63). LVM was measured using echocardiography. Body composition was determined using BOD POD and peak oxygen uptake (peak V02) was measured by a progressive exercise test. Height, weight and blood pressure were also measured. LVM was not significantly elevated in p-DCD compared to controls. Peak V02 was lower and SBP, BMI, HR, and BF(%) were significantly higher in p-DCD. They also demonstrated elevated stroke volume (SV), cardiac output (CO), end-diastolic volume, and ventricular diameter in diastole. In regression analyses, p-DCD was a significant predictor of SV and CO after accounting for height, FFM, V02FFM, and sex. These differences in children with p-DCD indicate obesity related changes in the left ventricle and may represent early stages of developing hypertrophy of the left ventricle.
    • A Life without Gluten: Dietary Adherence, Physical Activity and Motives

      Crawford, Amy M; Applied Health Sciences Program
      The purpose of this study was to look at individuals living on a gluten-free diet (GFD), their dietary adherence, PA levels and the reasons why they engage in these lifestyle behaviours consistent with Organismic Integration Theory (Deci & Ryan, 2002). Participants (N = 202; Mage = 42.35 years, SDage = 12.43 years) completed a series of online questionnaires. GFD adherence (74.7%) across the previous week was consistent with existing literature (Dowd et al., 2013), but participant physical activity scores were higher than reported normative values (p = .00; Wilson et al., 2010). Specific motives predicted gluten-free dietary adherence (i.e., integrated and identified regulations) and PA (i.e., intrinsic and identified regulations; p < .05). Findings may be used by health professionals to inform behavioural interventions consistent with OIT (Deci & Ryan, 2002).
    • Linking of stress offset score (SOS), work satisfaction, and organizational commitment to intentions to quit

      Alexander, Angela.; Applied Health Sciences Program (Brock University, 2007-05-21)
      The purpose of this study was to identify the impact of stressors and offsetting satistiers, measured in this study with Stress Offset Score (SOS), on intentions to quit and examine the mediating and moderating effects of three facets of work satisfaction (job satisfaction, pay satisfaction, and satisfaction with supervisor) and two facets of organizational commitment (affective and nonnative commitment) on this relationship. The sample was composed of 2990 employees from 21 public and private organizations. The interaction of each type of work satisfaction and organizational commitment, with SOS, was tested using Ordinary Least Squares (OLS) procedures. Intentions to quit was the dependent variable. The research questions were determine: (1) Does SOS predict intentions to quit? (2) Does work satisfaction mediate the predictive relationship of SOS on intentions to quit? (3) Does organizational commitment mediate the predictive relationship of SOS on intent to quit? (4) Does work satisfaction moderate the predictive relationship of SOS on intentions to quit? and (5) Does organizational commitment moderate the predictive relationship of SOS on intentions to quit? The results indicated that SOS was negatively correlated with intentions to quit. Each of the types of work satisfaction and organizational commitment variables showed a partial mediated relationship with SOS and each relationship was highly significant, while normative commitment explained more of the relationship then other mediators. The study also tested for interactions but no statistical significant relationships where established between any of the interaction terms (e.g., SOSxJob Satisfaction and SOSxAffcctive Commitment) and intentions to quit.
    • Maternal High Fat Feeding: Impact of Female Offspring Body Composition and Bone Health

      Castelli, Laura; Applied Health Sciences Program (Brock University, 2014-09-05)
      High fat diet (HFD) consumption in rodents alters body composition and weakens bones. Whether female offspring of mothers consuming a HFD are similarly affected at weaning and early adulthood is unclear. This research determined whether maternal HFD contributes to long-lasting alterations in body composition and bone health of female offspring. Rats were fed control or HFD for 10 weeks prior to and throughout pregnancy and lactation. Female offspring were studied at weaning or 3 months of age (consumed control diet). Main findings in female offspring: maternal HFD decreased lean mass, increased fat mass and femoral BMD at weaning, but not at 3 months; weanling femoral lipid composition reflected maternal diet, persisting to 3 months of age (decreased total and n6 polyunsaturates, increased saturates); and no differences in femoral strength at 3 months. In summary, 3 month old female offspring have similar body composition and bone health regardless of maternal diet.
    • Mechanisms of endothelin-1 induced reactive oxygen species production in vascular adventitial fibroblasts

      Chapman, Sandy.; Applied Health Sciences Program (Brock University, 2008-06-15)
      With the relationship between endothelin-1 (ET-1) stimulation and reactive oxygen species (ROS) production unknown in adventitial fibroblasts, I examined the ROS response to ET-1 and angiotensin (Ang II). ET-1 -induced ROS peaked following 4 hrs of ET-1 stimulation and was inhibited by an ETA receptor antagonist (BQ 123, 1 uM) an extracellular signal-regulated kinase (ERK) 1/2 inhibitor (PD98059, 10 uM), and by both a specific, apocynin (10 uM), and non-specific, diphenyleneiodonium (10 uM), NAD(P)H oxidase inhibitor. NOX2 knockout fibroblasts did not produce an ET-1 induced change in ROS levels. Ang II treatment increased ROS levels in a biphasic manner, with the second peak occurring 6 hrs following stimulation. The secondary phase of Ang II induced ROS was inhibited by an ATi receptor antagonist, Losartan (100 uM) and BQ 123. In conclusion, ET-1 induces ROS production primarily through an ETA-ERKl/2 NOX2 pathway, additionally, Ang II-induced ROS production also involves an ETa pathway.
    • Mediating Influence of Physical Fitness on the Relationship between Academic Performance and Motor Proficiency

      Alexander, Ryan; Applied Health Sciences Program (Brock University, 2011-08-10)
      We explored the potential mediating influence of physical fitness on the relationship between academic performance and motor proficiency in children. 1864 students (F:926, M:938, age 11.91 (SD:0.34). Academic achievement was derived from an average of standardized tests of reading, writing, and math. The Bruininks-Oseretsky Test of Motor Performance (short-form) determined motor proficiency. Fitness (peak oxygen uptake) was established with the Léger 20-m Shuttle Run Test. OLS regression identified several significant predictors of academic performance. After controlling for age (p=0.0135), gender (p<0.0001), and parental education (p<0.0001), motor proficiency (p<0.0001), was significant. After adding physical fitness (p=0.0030) to the model the effect of motor proficiency remained significant however the point estimate was reduced from 0.0034 (p<0.0001) to 0.0026 (p<0.0001). These results suggest that physical fitness plays a mediating role on the relationship between academic performance and motor proficiency although both aerobic fitness and motor proficiency have independent roles.
    • The Mediating Role of Perceived Scholastic Competence in the Relationship Between Motor Coordination and Academic Performance

      Lemay, Alex; Applied Health Sciences Program
      Children with developmental coordination disorder (DCD) are often referred to as clumsy because of their compromised motor coordination. Clumsiness and slow movement performances while scripting in children with DCD often result in poor academic performance and a diminished sense of scholastic competence. This study purported to examine the mediating role of perceived scholastic competence in the relationship between motor coordination and academic performance in children in grade six. Children receive a great deal of comparative information on their academic performances, which influence a student's sense of scholastic competence and self-efficacy. The amount of perceived academic self-efficacy has significant impact on academic performance, their willingness to complete academic tasks, and their self-motivation to improve where necessary. Independent t-tests reveal a significant difference (p < .001) between DCD and non-DCD groups when compared against their overall grade six average with the DCD group performing significantly lower. Independent t-tests found no significant difference between DCD and non-DCD groups for perceived scholastic competence. However, multiple linear regression analysis revealed a significant mediating role of 15% by perceived scholastic competence when examining the relationship between motor coordination and academic performance. While children with probable DCD may not rate their perceived scholastic competence as less than their healthy peers, there is a significant mediating effect on their academic performance.
    • Menstrual status and thermoregulatory responses of active adolescents during exercise in a cold environment

      Cunliffe, Melora.; Applied Health Sciences Program (Brock University, 2002-05-21)
      This study examined the interactions between the reproductive status and the thermoregulatory responses during exercise in the cold in girls involved in competitive sports. Four girls with established menstrual cycles comprised the eumenorrheic menarcheal group (EM) and 5 non-menstruating girls comprised the pre-menarcheal group (PM). During the first visit maximal oxygen consumption, height, weight and percent body fat (%BF) were measured. The second visit involved: a determination of metabolic rate in thermoneutrality (21°C) involving 10-min rest and 20-min cycling (30% of VCL max), and a cold stress test (5°C, 40% humidity, <0.3 m/s air velocity) involving 20-min rest and 40-min cycling (30% of VCL max.). Subjects in the EM group were tested twice in the chamber during the follicular and luteal phases. Pre-menarcheal subjects were found to have significantly (p<0.05) lower core temperatures during the final stages of cold exposure. Overall, body fat was not significantly correlated with core temperature in the cold, however there was a significant surface-to-mass ratio difference between the groups. While in the follicular phase, EM girls had a higher core temperature during cold exposure. Therefore, reproductive hormonal status seems to be an important factor in terms of cold tolerance in females during adolescence.
    • Migrations and gradations : reappraising the health profile of immigrants to Canada

      Hawes, Robert Alexander.; Applied Health Sciences Program (Brock University, 2005-06-15)
      New immigrants to Canada typically have a more favourable health profile than the non-immigrant population. This phenomenon, known as the 'healthy immigrant effect', has been attributed to both the socioeconomic advantage (ie. educational attainment, occupational opportunity) of non-refugee immigrants and existing screening protocols that admit only the healthiest of persons to Canada. It has been suggested that this health advantage diminishes as the time of residence in Canada increases, due in part to the adoption of health-risk behaviours such as alcohol and cigarette use, an increase in excess body weight, and declining rates of physical activity. However, the majority of health research concerning immigrants to Canada has been limited to cross-sectional studies (Dunn & Dyck, 2000; Newbold & Danforth, 2003), which may mask an immigrant-specific cohort effect. Furthermore, the practice of aggregating foreign-bom persons by geographical regions or treating all immigrants as a homogeneous group may also obfuscate intra-immigrant differences in health. Accordingly, this study uses the Canadian National Population Health Surveys (NPHS) and data from the United Nations Development Program (UNDP) to prospectively evaluate factors that predict health status among immigrants to Canada. Each immigrant in the NPHS was linked to the UNDP Human Development Index of their country of birth, which uses a combined measure of health, education, and per capita income of the populace. The six-year change in health function, psychological distress, and self-rated health were considered from a population health perspective (Evans, 1994), using generalized-estimating equations (GEE) to examine the compounding effect of past and recent predictors of health. Demographic
    • Mindfulness therapy as a means to improve sexual satisfaction in couples with neuromuscular disabilities

      Seliman, Merna; Applied Health Sciences Program
      Research regarding sexuality after neuromuscular disabilities has focused on either men or women separately, without considering the couple and how acquiring a disability may influence relationships. The objective of this study was to investigate the effects of an 8-week modified mindfulness intervention on sexual satisfaction in couples where one or both partners are living with neuromuscular disability. One couple (male age 42, female age 44) with the female living with neuromuscular disability (relapsing remitting MS, 11 years since diagnosis) participated in the study. The mindfulness intervention was administered to participants via a booklet and the exercises were explained verbally after the baseline interview. The booklet contained a total of eight mindfulness-based exercises for each week of the intervention. The exercises were explained in a step-by-step manner in the booklet. The booklet also included reflection questions at the end of each exercise in order to prompt the couple to journal about their experiences and record how much time they dedicated to that exercise per week. The exercises were carried out at home. The intervention also included a psycho-education session that was offered at week five of the intervention. The psycho-education session aimed to challenge thought patterns and negative beliefs about sex and physical abilities. It also involved a discussion about body-image as it relates to mindfulness. Testing involved a sexual satisfaction questionnaire that was completed by each member of the couple individually at baseline and at the end of the 8-week intervention. II Also, an in-depth semi-structured phenomenological interview of the couple together was conducted at baseline and at the end of the 8-week intervention. The results of this study showed that sexual satisfaction and sexual-self view have improved for the couple as a result of participating in the 8-week mindfulness intervention. In addition, the couple reported an improvement in communication, understanding, and awareness. Sensate focus exercises enhanced intimacy between the couple. Themes such as acceptance and feeling present in the moment were discerned from phenomenological analysis. These findings show promise for mindfulness-based therapies to enhance sexual satisfaction and relationship satisfaction in couples living with neuromuscular disabilities.
    • Muscle strength and activation characteristics of power- trained and non-athlete boys and men

      Mitchell, Cameron Jeffrey.; Applied Health Sciences Program (Brock University, 2009-02-16)
      During maturation, muscle strength is enhanced through muscle growth, although neuro-muscular factors are also believed to be involved. In adults, training for power sports has been shown to enhance muscle strength and activation. The purpose of this study was to examine muscle strength and activation in power-trained athletes (POW) compared with non-athletes (CON), in boys and in adults. After familiarization subjects performed ten 5-s explosive maximal voluntary contractions for elbow and knee flexion and extension. The adults were stronger then the boys and the adult POW were stronger then the adult CON, even after correction for muscle size. Normalized rate of torque development was higher in the adults then in the boys and higher in the POW then CON boys. The rate of muscle activation was higher in the adults and POW groups. The results suggest that maturation and power-training have an additive effect on muscle activation.
    • Myosin Regulatory Light Chain Phosphorylation and Its Effect on the Contractile Economy of Mouse Fast Muscle

      Bunda, Jordan; Applied Health Sciences Program
      Activated by elevations in myoplasmic calcium concentration, myosin light chain kinase (skMLCK) phosphorylates the regulatory light chains (RLCs) of fast muscle myosin. This covalent modification potentiates force production, but requires an investment of ATP. Our objective was to investigate the effect of RLC phosphorylation on the contractile economy (mechanical output:metabolic input) of fast twitch skeletal muscle. Extensor digitorum longus muscles isolated from Wildtype and skMLCK-/- mice mounted in vitro (25°C) were subjected to repetitive low-frequency stimulation (10Hz,15s) known to cause activation of skMLCK, and staircase potentiation of force. With a 3-fold increase in RLC phosphate content, Wildtype generated 44% more force than skMLCK-/- muscles over the stimulation period (P = .002), without an accompanied increase in energy cost (P = .449). Overall, the contractile economy of Wildtype muscles, with an intact RLC phosphorylation mechanism, was 73% greater than skMLCK /- muscles (P = .043), demonstrating an important physiological function of skMLCK during repetitive contractile activity.