Matching Items (32)
Description
Background: Evidence about the purported hypoglycemic and hypolipidemic effects of nopales (prickly pear cactus pads) is limited. Objective: To evaluate the efficacy of nopales for improving cardiometabolic risk factors and oxidative stress, compared to control, in adults with hypercholesterolemia. Design: In a randomized crossover trial, participants were assigned to a 2-wk intervention with 2 cups/day of nopales or cucumbers (control), with a 2 to 3-wk washout period. The study included 16 adults (5 male; 46±14 y; BMI = 31.4±5.7 kg/m2) with moderate hypercholesterolemia (low density lipoprotein cholesterol [LDL-c] = 137±21 mg/dL), but otherwise healthy. Main outcomes measured included: dietary intake (energy, macronutrients and micronutrients), cardiometabolic risk markers (total cholesterol, LDL-c, high density lipoprotein cholesterol [HDL-c], triglycerides, cholesterol distribution in LDL and HDL subfractions, glucose, insulin, homeostasis model assessment, and C-reactive protein), and oxidative stress markers (vitamin C, total antioxidant capacity, oxidized LDL, and LDL susceptibility to oxidation). Effects of treatment, time, or interactions were assessed using repeated measures ANOVA. Results: There was no significant treatment-by-time effect for any dietary composition data, lipid profile, cardiometabolic outcomes, or oxidative stress markers. A significant time effect was observed for energy, which was decreased in both treatments (cucumber, -8.3%; nopales, -10.1%; pTime=0.026) mostly due to lower mono and polyunsaturated fatty acids intake (pTime=0.023 and pTime=0.003, respectively). Both treatments significantly increased triglyceride concentrations (cucumber, 14.8%; nopales, 15.2%; pTime=0.020). Despite the lack of significant treatment-by-time effects, great individual response variability was observed for all outcomes. After the cucumber and nopales phases, a decrease in LDL-c was observed in 44% and 63% of the participants respectively. On average LDL-c was decreased by 2.0 mg/dL (-1.4%) after the cucumber phase and 3.9 mg/dL (-2.9%) after the nopales phase (pTime=0.176). Pro-atherogenic changes in HDL subfractions were observed in both interventions over time, by decreasing the proportion of HDL-c in large HDL (cucumber, -5.1%; nopales, -5.9%; pTime=0.021) and increasing the proportion in small HDL (cucumber, 4.1%; nopales, 7.9%; pTime=0.002). Conclusions: These data do not support the purported benefits of nopales at doses of 2 cups/day for 2-wk on markers of lipoprotein profile, cardiometabolic risk, and oxidative stress in hypercholesterolemic adults.
ContributorsPereira Pignotti, Giselle Adriana (Author) / Vega-Lopez, Sonia (Thesis advisor) / Gaesser, Glenn (Committee member) / Keller, Colleen (Committee member) / Shaibi, Gabriel (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2013
Description
Purpose: Exercise interventions often result in less than predicted weight loss or even weight gain in some individuals, with over half of the weight that is lost often being regained within one year. The current study hypothesized that one year following a 12-week supervised exercise intervention, women who continued to exercise regularly but initially gained weight would lose the weight gained, reverting back to baseline with no restoration of set-point, or continue to lose weight if weight was initially lost. Conversely, those who discontinued purposeful exercise at the conclusion of the study were expected to continue to gain or regain weight. Methods: 24 women who completed the initial 12-week exercise intervention (90min/week of supervised treadmill walking at 70%VO2peak) participated in a follow-up study one year after the conclusion of the exercise intervention. Subjects underwent Dual-energy X-Ray Absorptiometry at baseline, 12-weeks, and 15 months, and filled out physical activity questionnaires at 15 months. Results: A considerable amount of heterogeneity was observed in body weight and fat mass changes among subjects, but there was no significant overall change in weight or fat mass from baseline to follow-up. 15 women were categorized as compensators and as a group gained weight (+ 0.94±3.26kg) and fat mass (+0.22±3.25kg) compared to the 9 non-compensators who lost body weight (-0.26±3.59kg) and had essentially no change in fat mass (+0.01±2.61kg) from 12-weeks to follow-up. There was a significant between group difference (p=.003) in change in fat mass from 12-weeks to follow-up between subjects who continued to regularly vigorously exercise (-2.205±3.070kg), and those who did not (+1.320±2.156kg). Additionally, energy compensation from baseline to 12-weeks and early body weight and composition changes during the intervention were moderate predictors of body weight and composition changes from baseline to follow-up. Conclusion: The main finding of this study is that following a 12-week supervised exercise intervention, women displayed a net loss of fat mass during the follow-up period if regular vigorous exercise was continued, regardless of whether they were classified as compensators or non-compensators during the initial intervention.
ContributorsCabbage, Clarissa Marie (Author) / Gaesser, Glenn (Thesis advisor) / Chisum, Jack (Committee member) / Campbell, Kathryn (Committee member) / Arizona State University (Publisher)
Created2013
Description
Eccentric muscle action (ECC) occurs when the force exerted by a working muscle is less than that of an outside resistance. This is characterized by muscle lengthening, despite actin-myosin crossbridge formation. Research has indicated that muscles acting eccentrically are capable of producing more force when compared to muscles acting concentrically. Further, research has shown ECC muscle actions may have different fatigue patterns that CON actions. The purpose of this study was to determine if a) ECC bench press yields greater strength than concentric (CON) as measured by one-repetition maximum (1RM), b) there is a difference between the number of repetitions that can be completed concentrically and eccentrically under the same relative intensities of 1RM (90%, 80%, 70%, 60%), c) a prediction model may be able to predict ECC 1RM from CON 1RM or CON repetitions to fatigue. For this study, 30 healthy males (age = 24.63 + 5.6 years) were tested for 1RM in CON and ECC bench press, as well as the number of repetitions they were able to complete at various intensities of mode-specific 1RM. A mechanical hoist was affixed to a gantry crane and placed over a standard weightlifting bench. The hoist was connected to 45lb plates that were loaded on a standard barbell, which allowed for mechanical raising and lowering of the barbell. For CON repetitions, the weight was mechanically lowered to the chest and the participant pressed it up. For ECC repetitions, the weight was mechanically raised and the participant lowered it. Paired t-tests showed that ECC 1RM was significantly (p < 0.05) greater than CON 1RM (ECC =255.17 + 68.37lbs, CON = 205.83 + 58.43lbs). There was a significant difference (p < 0.05) between the number of repetitions completed at 90% 1RM (CON = 4.57 + 2.21 repetitions, ECC = 7.67 + 3.24 repetitions). There were no differences in repetitions completed at any other intensity 1RM. CON 1RM and the number of repetitions completed with two different absolute loads (130-150lbs and 155-175lbs) concentrically and eccentrically were valid predictors of ECC 1RM. These data indicate that ECC actions yield increased force capabilities than CON actions, there is no difference in the rate of the fatigue, and ECC 1RM may be predicted from various CON tests.
ContributorsKelly, Stephen B., Jr (Author) / Hooker, Steven (Thesis advisor) / Brown, Lee (Committee member) / Buman, Matthew (Committee member) / Gaesser, Glenn (Committee member) / Swan, Pamela (Committee member) / Arizona State University (Publisher)
Created2013
Description
INTRODUCTION: Exercise performed at moderate to vigorous intensities has been shown to generate a post exercise hypotensive response. Whether this response is observed with very low exercise intensities is unclear. PURPOSE: To compare post physical activity ambulatory blood pressure (ABP) response to a single worksite walking day and a normal sedentary work day in pre-hypertensive adults. METHODS: Participants were 7 pre-hypertensive (127 + 8 mmHg / 83 + 8 mmHg) adults (3 male, 4 female, age = 42 + 12 yr) who participated in a randomized, cross-over study that included a control and a walking treatment. Only those who indicated regularly sitting at least 8 hours/day and no structured physical activity were enrolled. Treatment days were randomly assigned and were performed one week apart. Walking treatment consisted of periodically increasing walk time up to 2.5 hours over the course of an 8 hour work day on a walking workstation (Steelcase Company, Grand Rapids, MI). Walk speed was set at 1 mph. Participants wore an ambulatory blood pressure cuff (Oscar 2, SunTech Medical, Morrisville, NC) for 24-hours on both treatment days. Participants maintained normal daily activities on the control day. ABP data collected from 9:00 am until 10:00 pm of the same day were included in statistical analyses. Linear mixed models were used to detect differences in systolic (SBP) and diastolic blood pressure (DBP) by treatment condition over the whole day and post workday for the time periods between 4 -10 pm when participants were no longer at work. RESULTS:BP was significantly lower in response to the walking treatment compared to the control day (Mean SBP 126 +7 mmHg vs.124 +7 mmHg, p=.043; DBP 80 + 3 mmHg vs. 77 + 3 mmHg, p = 0.001 respectively). Post workday (4:00 to 10:00 pm) SBP decreased 3 mmHg (p=.017) and DBP decreased 4 mmHg (p<.001) following walking. CONCLUSION: Even low intensity exercise such as walking on a walking workstation is effective for significantly reducing acute BP when compared to a normal work day.
ContributorsZeigler, Zachary (Author) / Swan, Pamela (Thesis advisor) / Buman, Matthew (Committee member) / Gaesser, Glenn (Committee member) / Arizona State University (Publisher)
Created2013
Description
Dietary protein is known to increase postprandial thermogenesis more so than carbohydrates or fats, probably related to the fact that amino acids have no immediate form of storage in the body and can become toxic if not readily incorporated into body tissues or excreted. It is also well documented that subjects report greater satiety on high- versus low-protein diets and that subject compliance tends to be greater on high-protein diets, thus contributing to their popularity. What is not as well known is how a high-protein diet affects resting metabolic rate over time, and what is even less well known is if resting metabolic rate changes significantly when a person consuming an omnivorous diet suddenly adopts a vegetarian one. This pilot study sought to determine whether subjects adopting a vegetarian diet would report decreased satiety or demonstrate a decreased metabolic rate due to a change in protein intake and possible increase in carbohydrates. Further, this study sought to validate a new device called the SenseWear Armband (SWA) to determine if it might be sensitive enough to detect subtle changes in metabolic rate related to diet. Subjects were tested twice on all variables, at baseline and post-test. Independent and related samples tests revealed no significant differences between or within groups for any variable at any time point in the study. The SWA had a strong positive correlation to the Oxycon Mobile metabolic cart but due to a lack of change in metabolic rate, its sensitivity was undetermined. These data do not support the theory that adopting a vegetarian diet results in a long-term change in metabolic rate.
ContributorsMoore, Amy (Author) / Johnston, Carol (Thesis advisor) / Appel, Christy (Thesis advisor) / Gaesser, Glenn (Committee member) / Arizona State University (Publisher)
Created2012
Description
The health benefits of physical activity are widely accepted. Emerging research also indicates that sedentary behaviors can carry negative health consequences regardless of physical activity level. This dissertation explored four projects that examined measurement properties of physical activity and sedentary behavior monitors. Project one identified the oxygen costs of four other care activities in seventeen adults. Pushing a wheelchair and pushing a stroller were identified as moderate-intensity activities. Minutes spent engaged in these activities contribute towards meeting the 2008 Physical Activity Guidelines. Project two identified the oxygen costs of common cleaning activities in sixteen adults. Mopping a floor was identified as moderate-intensity physical activity, while cleaning a kitchen and cleaning a bathtub were identified as light-intensity physical activity. Minutes spent engaged in mopping a floor contributes towards meeting the 2008 Physical Activity Guidelines. Project three evaluated the differences in number of minutes spent in activity levels when utilizing different epoch lengths in accelerometry. A shorter epoch length (1-second, 5-seconds) accumulated significantly more minutes of sedentary behaviors than a longer epoch length (60-seconds). The longer epoch length also identified significantly more time engaged in light-intensity activities than the shorter epoch lengths. Future research needs to account for epoch length selection when conducting physical activity and sedentary behavior assessment. Project four investigated the accuracy of four activity monitors in assessing activities that were either sedentary behaviors or light-intensity physical activities. The ActiGraph GT3X+ assessed the activities least accurately, while the SenseWear Armband and ActivPAL assessed activities equally accurately. The monitor used to assess physical activity and sedentary behaviors may influence the accuracy of the measurement of a construct.
ContributorsMeckes, Nathanael (Author) / Ainsworth, Barbara E (Thesis advisor) / Belyea, Michael (Committee member) / Buman, Matthew (Committee member) / Gaesser, Glenn (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2012
Description
Birds have plasma glucose levels that are 1.5-2 times greater than mammals of similar body mass in addition to higher free fatty acid concentrations, both of which would typically impair endothelium-dependent vasodilation if observed in mammals. Endothelium-dependent vasodilation can be stimulated in mammals through the use of acetylcholine (ACh), which primarily acts through nitric oxide (NO) and cyclooxygenase (COX)-mediated pathways, with varying reliance on endothelial-derived hyperpolarizing factors (EDHFs). Very few studies have been conducted on small resistance systemic arteries from birds. The hypothesis was that because birds have naturally high glucose and free fatty acid concentrations, ACh-induced vasodilation of isolated arteries from mourning doves (Zenaida macroura) would be independent of endothelial-derived factors and resistant to high glucose-mediated vascular dysfunction. Small resistance mesenteric and cranial tibial (c. tibial) arteries were pre-constricted to 50% of resting inner diameter with phenyleprine then exposed to increasing doses of ACh (10-9 to 10-5 μM) or the NO donor, sodium nitroprusside (SNP; 10-12 to 10-3 μM). For both vessel beds, ACh-induced vasodilation occurred mainly through the activation of potassium channels, whereas vasodilation of mesenteric arteries additionally occurred through COX. Although arteries from both vessel beds fully dilated with exposure to sodium nitroprusside, ACh-mediated vasodilation was independent of NO. To examine the effect of high glucose on endothelium-dependent vasodilation, ACh dose response curves were conducted following exposure of isolated c. tibial arteries to either a control solution (20mM glucose) or high glucose (30mM). ACh-induced vasodilation was significantly impaired (p = 0.013) when exposed to high glucose, but normalized in subsequent vessels with pre-exposure to the superoxide dismutase mimetic tiron (10 mM). Superoxide concentrations were likewise significantly increased (p = 0.0072) following exposure to high glucose. These findings indicate that dove arteries do not appear to have endogenous mechanisms to counteract the deleterious effects of oxidative stress. Additional studies are required to assess whether endogenous mechanisms exist to protect avian vascular reactivity from systemic hyperglycemia.
ContributorsJarrett, Catherine Lee (Author) / Sweazea, Karen L (Thesis advisor) / Johnston, Carol (Committee member) / Gaesser, Glenn (Committee member) / Arizona State University (Publisher)
Created2012
Description
Background: Heart failure is the leading cause of hospitalization in older adults and has the highest 30-day readmission rate of all diagnoses. An estimated 30 to 60 percent of older adults lose some degree of physical function in the course of an acute hospital stay. Few studies have addressed the role of posture and mobility in contributing to, or improving, physical function in older hospitalized adults. No study to date that we are aware of has addressed this in the older heart failure population.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
Purpose: To investigate the predictive value of mobility during a hospital stay and patterns of mobility during the month following discharge on hospital readmission and 30-day changes in functional status in older heart failure patients.
Methods: This was a prospective observational study of 21 older (ages 60+) patients admitted with a primary diagnosis of heart failure. Patients wore two inclinometric accelerometers (rib area and thigh) to record posture and an accelerometer placed at the ankle to record ambulatory activity. Patients wore all sensors continuously during hospitalization and the ankle accelerometer for 30 days after hospital discharge. Function was assessed in all patients the day after hospital discharge and again at 30 days post-discharge.
Results: Five patients (23.8%) were readmitted within the 30 day post-discharge period. None of the hospital or post-discharge mobility measures were associated with readmission after adjustment for covariates. Higher percent lying time in the hospital was associated with slower Timed Up and Go (TUG) time (b = .08, p = .01) and poorer hand grip strength (b = -13.94, p = .02) at 30 days post-discharge. Higher daily stepping activity during the 30 day post-discharge period was marginally associated with improvements in SPPB scores at 30 days (b = <.001, p = .06).
Conclusion: For older heart failure patients, increased time lying while hospitalized is associated with slower walking time and poor hand grip strength 30 days after discharge. Higher daily stepping after discharge may be associated with improvements in physical function at 30 days.
ContributorsFloegel, Theresa A (Author) / Buman, Matthew P (Thesis advisor) / Hooker, Steven (Committee member) / Dickinson, Jared (Committee member) / DerAnanian, Cheryl (Committee member) / McCarthy, Marianne (Committee member) / Arizona State University (Publisher)
Created2015
Description
Obesity impairs skeletal muscle maintenance and regeneration, a condition that can progressively lead to muscle loss, but the mechanisms behind it are unknown. Muscle is primarily composed of multinucleated cells called myotubes which are derived by the fusion of mononucleated myocytes. A key mediator in this process is the cellular fusion protein syncytin-1. This led to the hypothesis that syncytin-1 could be decreased in the muscle of obese/insulin resistant individuals. In contrast, it was found that obese/insulin resistant subjects had higher syncytin-1 expression in the muscle compared to that of the lean subjects. Across the subjects, syncytin-1 correlated significantly with body mass index, percent body fat, blood glucose and HbA1c levels, insulin sensitivity and muscle protein fractional synthesis rate. The concentrations of specific plasma fatty acids, such as the saturated fatty acid (palmitate) and monounsaturated fatty acid (oleate) are known to be altered in obese/insulin resistant humans, and also to influence the protein synthesis in muscle. Therefore, it was evaluated that the effects of palmitate and oleate on syncytin-1 expression, as well as 4E-BP1 phosphorylation, a key mechanism regulating muscle protein synthesis in insulin stimulated C2C12 myotubes. The results showed that treatment with 20 nM insulin, 300 µM oleate, 300 µM oleate +20 nM insulin and 300 µM palmitate + 300 µM oleate elevated 4E-BP1 phosphorylation. At the same time, 20 nM insulin, 300 µM palmitate, 300 µM oleate + 20 nM insulin and 300 µM palmitate + 300 µM oleate elevated syncytin-1 expression. Insulin stimulated muscle syncytin-1 expression and 4E-BP1 phosphorylation, and this effect was comparable to that observed in the presence of oleate alone. However, the presence of palmitate + oleate diminished the stimulatory effect of insulin on muscle syncytin-1 expression and 4E-BP1 phosphorylation. These findings indicate oleate but not palmitate increased total 4E-BP1 phosphorylation regardless of insulin and the presence of palmitate in insulin mediated C2C12 cells. The presence of palmitate inhibited the upregulation of total 4EB-P1 phosphorylation. Palmitate but not oleate increased syncytin-1 expression in insulin mediated C2C12 myotubes. It is possible that chronic hyperinsulinemia in obesity and/or elevated levels of fatty acids such as palmitate in plasma could have contributed to syncytin-1 overexpression and decreased muscle protein fractional synthesis rate in obese/insulin resistant human muscle.
ContributorsRavichandran, Jayachandran (Author) / Katsanos, Christos (Thesis advisor) / Coletta, Dawn (Committee member) / Dickinson, Jared (Committee member) / Arizona State University (Publisher)
Created2017
Description
Walking interventions focused on increasing step counts are typically associated with salutary effects on glycemia, fasting insulin, insulin resistance and blood lipids which may be in turn associated with improvements in cardiorespiratory fitness (peak oxygen uptake – VO2peak) and vascular stiffness. We hypothesized that a novel 4-month, behavioral economics-based walking intervention would have favorable effects on glucose homeostasis and blood lipids and that these in turn would be related to VO2peak and vascular stiffness (carotid femoral pulse wave velocity – cfPWV).
We carried out secondary analyses on a subsample of sedentary, overweight/obese adults who participated in a 4-month, 2x2, randomized-controlled walking intervention examining the effects of goal setting (static v. adaptive goals) and rewards (immediate v. delayed) on steps/day (N=96). Fasting blood samples (n=58) were collected from participants before and after the intervention. Premenopausal females were in the follicular phase of their menstrual cycles. Lipid and glucose levels were measured using an automated chemistry analyzer, while insulin was measured using radio-immunoassay. Homeostatic model of insulin resistance (HOMA-IR) was calculated using the following formula (HOMA-IR=glucose x insulin / 405). We examined associations [partial correlations (adjusted for age)] between changes in blood biomarkers and VO2peak and cfPWV, irrespective of group, and we used linear mixed models to examine between-group differences in levels of and change in biomarker outcomes.
Groups did not differ in overall levels of, or degree of change in, biomarker outcomes (all p>0.05). Mean changes, irrespective of group, in biomarkers were as follows: glucose Δ= 0.74± 4.5mg/dl; insulin Δ= 0.09 ± 4.1 µU/ml; total cholesterol Δ= 0.24 ± 20.6 mg/dl; HDL-C Δ= 0.27 ± 5.1 mg/dl; LDL-C Δ= 1.3 ± 19.9 mg/dl; triglycerides Δ= 1.7 ± 27.2 mg/dl; HOMA-IR Δ = -.0548 ± 1.05). We found no significant associations between change in biomarker levels and change in VO2peak or change in cfPWV (all correlation coefficients < 0.15; p > 0.05).
A 4-month, behavioral economics-based mHealth intervention focused on increasing steps/day did not bring about favorable changes on markers of glycemia, insulin resistance and blood lipids.
We carried out secondary analyses on a subsample of sedentary, overweight/obese adults who participated in a 4-month, 2x2, randomized-controlled walking intervention examining the effects of goal setting (static v. adaptive goals) and rewards (immediate v. delayed) on steps/day (N=96). Fasting blood samples (n=58) were collected from participants before and after the intervention. Premenopausal females were in the follicular phase of their menstrual cycles. Lipid and glucose levels were measured using an automated chemistry analyzer, while insulin was measured using radio-immunoassay. Homeostatic model of insulin resistance (HOMA-IR) was calculated using the following formula (HOMA-IR=glucose x insulin / 405). We examined associations [partial correlations (adjusted for age)] between changes in blood biomarkers and VO2peak and cfPWV, irrespective of group, and we used linear mixed models to examine between-group differences in levels of and change in biomarker outcomes.
Groups did not differ in overall levels of, or degree of change in, biomarker outcomes (all p>0.05). Mean changes, irrespective of group, in biomarkers were as follows: glucose Δ= 0.74± 4.5mg/dl; insulin Δ= 0.09 ± 4.1 µU/ml; total cholesterol Δ= 0.24 ± 20.6 mg/dl; HDL-C Δ= 0.27 ± 5.1 mg/dl; LDL-C Δ= 1.3 ± 19.9 mg/dl; triglycerides Δ= 1.7 ± 27.2 mg/dl; HOMA-IR Δ = -.0548 ± 1.05). We found no significant associations between change in biomarker levels and change in VO2peak or change in cfPWV (all correlation coefficients < 0.15; p > 0.05).
A 4-month, behavioral economics-based mHealth intervention focused on increasing steps/day did not bring about favorable changes on markers of glycemia, insulin resistance and blood lipids.
ContributorsHook, Benjamin E. (Author) / Angadi, Siddhartha (Thesis director) / Gaesser, Glenn (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05