Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Subject: search.filters.subject.1116 Medical Physiology

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Objectively Measured Physical Activity Is Associated With Body Composition and Metabolic Profiles of Pacific and New Zealand European Women With Different Metabolic Disease Risks.
    (Frontiers Media SA, 26/05/2021) Slater J; Kruger R; Douwes J; O'Brien WJ; Corbin M; Miles-Chan JL; Breier BH
    Objective: To assess associations between physical activity (PA), body composition, and biomarkers of metabolic health in Pacific and New Zealand European (NZE) women who are known to have different metabolic disease risks. Methods: Pacific (n = 142) or NZE (n = 162) women aged 18-45 years with a self-reported body mass index (BMI) of either 18.5-25.0 kg⋅m-2 or ≥30.0 kg⋅m-2 were recruited and subsequently stratified as either low (<35%) or high (≥35%) BF%, with approximately half of each group in either category. Seven-day accelerometery was used to assess PA levels. Fasting blood was analysed for biomarkers of metabolic health, and whole body dual-energy X-ray absorptiometry (DXA) was used to estimate body composition. Results: Mean moderate-to-vigorous physical activity (MVPA; min⋅day-1) levels differed between BF% (p < 0.05) and ethnic (p < 0.05) groups: Pacific high- 19.1 (SD 15.2) and low-BF% 26.3 (SD 15.6) and NZE high- 30.5 (SD 19.1) and low-BF% 39.1 (SD 18.4). On average Pacific women in the low-BF% group engaged in significantly less total PA when compared to NZE women in the low-BF% group (133 cpm); no ethnic difference in mean total PA (cpm) between high-BF% groups were observed: Pacific high- 607 (SD 185) and low-BF% 598 (SD 168) and NZE high- 674 (SD 210) and low-BF% 731 (SD 179). Multiple linear regression analysis controlling for age and deprivation showed a significant inverse association between increasing total PA and fasting plasma insulin among Pacific women; every 100 cpm increase in total PA was associated with a 6% lower fasting plasma insulin; no significant association was observed in NZE women. For both Pacific and NZE women, there was an 8% reduction in fasting plasma insulin for every 10-min increase in MVPA (p ≤ 0.05). Conclusion: Increases in total PA and MVPA are associated with lower fasting plasma insulin, thus indicating a reduction in metabolic disease risk. Importantly, compared to NZE, the impact of increased total PA on fasting insulin may be greater in Pacific women. Considering Pacific women are a high metabolic disease risk population, these pre-clinical responses to PA may be important in this population; indicating promotion of PA in Pacific women should remain a priority.
  • Thumbnail Image
    Item
    The effect of oestrogen on cerebrovascular regulation in eumenorrheic women : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science, Massey University, Wellington, New Zealand
    (Massey University, 2020) Korad, Stephanie
    Women experience fluctuating sex hormone concentrations throughout their lifetime and while their role in reproduction is well documented, there is little knowledge of the effects of the changing hormone concentrations on women’s cerebrovascular health. Therefore, this study examined dynamic cerebral autoregulation (dCA) in 10 healthy eumenorrheic women (28 ± 7 years) volunteers. The participants dCA was examined at three different phases of the menstrual cycle: early follicular (EF; when oestrogen and progesterone concentrations are low), late follicular (LF; oestrogen concentrations are high, while progesterone remains steady), and mid-luteal (ML; oestrogen and progesterone concentrations are high). The dCA was assessed using the autoregulatory index (AI) of forced changes in blood pressure (BP) and mean middle cerebral blood velocity (MCAv) response, induced during phases of the Valsalva manoeuvre (VM). The VM is a four-phase manoeuvre that produces hyper- and hypotensive changes to blood pressure (BP): phase I (initial increase in BP), phase IIa (initial decrease in BP), phase IIb (stabilisation of BP), phase III (decrease in BP after cessation of breath-hold), and phase IV (overshoot in BP recovery). Resting mean arterial blood pressure (MAP, P= 0.409), MCAv (P= 0.635), and cerebrovascular conductance index (CVCi, P= 0.984) were not different throughout all trials. The partial pressure of endtidal carbon dioxide (PETCO₂) was unchanged between the trials (P = 0.907). The VM induced middle cerebral artery velocity mean (MCAvmean) differences between trials (interaction: P = 0.039), MCAv during mid-luteal (ML; 58 ± 15 cm/s) showed a significant difference to early follicular (EF; 51 ± 14 cm/s, P = 0.013) and late follicular (LF; 49 ± 15 cm/s, P = 0.024) during phase IIb of the VM. There were no differences in MAP (P = 0.233) and CVCi (P = 0.808) during the VM throughout the trials. AI presented no difference during phase II of the VM (P= 0.354), however, phase IV did show a trend (P= 0.086). The results of this study indicate that circulating ovarian hormone concentrations may regulate responses to dynamic cerebrovascular challenges.
  • Thumbnail Image
    Item
    Transcriptome and translational signaling following endurance exercise in trained skeletal muscle: Impact of dietary protein
    (American Physiological Society, 2011) Rowlands DS; Thomson JS; Timmons BW; Raymond F; Fuerholz A; Mansourian R; Zwahlen M-C; Métairon S; Glover E; Stellingwerff T; Kussmann M; Tarnopolsky MA
    Postexercise protein feeding regulates the skeletal muscle adaptive response to endurance exercise, but the transcriptome guiding these adaptations in well-trained human skeletal muscle is uncharacterized. In a crossover design, eight cyclists ingested beverages containing protein, carbohydrate and fat (PTN: 0.4, 1.2, 0.2 g/kg, respectively) or isocaloric carbohydrate and fat (CON: 1.6, 0.2 g/kg) at 0 and 1 h following 100 min of cycling. Biopsies of the vastus lateralis were collected at 3 and 48 h following to determine the early and late transcriptome and regulatory signaling responses via microarray and immunoblot. The top gene ontology enriched by PTN were: muscle contraction, extracellular matrix--signaling and structure, and nucleoside, nucleotide, and nucleic acid metabolism (3 and 48 h); developmental processes, immunity, and defense (3 h); glycolysis, lipid and fatty acid metabolism (48 h). The transcriptome was also enriched within axonal guidance, actin cytoskeletal, Ca2+, cAMP, MAPK, and PPAR canonical pathways linking protein nutrition to exercise-stimulated signaling regulating extracellular matrix, slow-myofibril, and metabolic gene expression. At 3 h, PTN attenuated AMPKα1Thr172 phosphorylation but increased mTORC1Ser2448, rps6Ser240/244, and 4E-BP1-γ phosphorylation, suggesting increased translation initiation, while at 48 h AMPKα1Thr172 phosphorylation and PPARG and PPARGC1A expression increased, supporting the late metabolic transcriptome, relative to CON. To conclude, protein feeding following endurance exercise affects signaling associated with cell energy status and translation initiation and the transcriptome involved in skeletal muscle development, slow-myofibril remodeling, immunity and defense, and energy metabolism. Further research should determine the time course and posttranscriptional regulation of this transcriptome and the phenotype responding to chronic postexercise protein feeding.
  • Thumbnail Image
    Item
    Pain Across the Menstrual Cycle: Considerations of Hydration
    (Frontiers Media S.A., 8/10/2020) Tan B; Philipp M; Hill S; Che Muhamed AM; Mündel T
    Chronic pain - pain that persists for more than 3 months - is a global health problem and is associated with tremendous social and economic cost. Yet, current pain treatments are often ineffective, as pain is complex and influenced by numerous factors. Hypohydration was recently shown to increase ratings of pain in men, but studies in this area are limited (n = 3). Moreover, whether hypohydration also affects pain in women has not been examined. In women, changes in the concentrations of reproductive hormones across menstrual phases may affect pain, as well as the regulation of body water. This indicates potential interactions between the menstrual phase and hypohydration on pain, but this hypothesis has yet to be tested. This review examined the literature concerning the effects of the menstrual phase and hypohydration on pain, to explore how these factors may interact to influence pain. Future research investigating the combined effects of hypohydration and menstrual phase on pain is warranted, as the findings could have important implications for the treatment of pain in women, interpretation of previous research and the design of future studies.