ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- Creators: Shepard, Christina
Description
ABSTRACT The hormone leptin is an important regulator of body weight and energy balance, while nitric oxide (NO) produced in the blood vessels is beneficial for preventing disease-induced impaired vasodilation and hypertension. Elevations in the free radical superoxide can result in impaired vasodilation through scavenging of NO. Omega 3 is a polyunsaturated fatty acid that is beneficial at reducing body weight and in lowering many cardiovascular risk factors like atherosclerosis. The present study was designed to examine the change in plasma concentrations of leptin, nitric oxide, and the antioxidant superoxide dismutase in addition to examining the association between leptin and NO in healthy normal weight adult female subjects before and following omega 3 intakes. Participants were randomly assigned to either a fish oil group (600 mg per day) or a control group (1000 mg of coconut oil per day) for 8 weeks. Results showed no significant difference in the percent change of leptin over the 8 week supplementation period for either group (15.3±31.9 for fish oil group, 7.83±27 for control group; p=0.763). The percent change in NO was similarly not significantly altered in either group (-1.97±22 decline in fish oil group, 11.8±53.9 in control group; p=0.960). Likewise, the percent change in superoxide dismutase for each group was not significant following 8 weeks of supplementation (fish oil group: 11.94±20.94; control group: 11.8±53.9; p=0.362). The Pearson correlation co-efficient comparing the percent change of both leptin and NO was r2= -0.251 demonstrating a mildly negative, albeit insignificant, relationship between these factors. Together, these findings suggest that daily supplementation with 600 mg omega 3 in healthy females is not beneficial for improving these cardiovascular risk markers. Future studies in this area should include male subjects as well as overweight subjects with larger doses of fish oil that are equivalent to three or more servings per week. The importance of gender cannot be underestimated since estrogen has protective effects in the vasculature of females that may have masked any further protective effects of the fish oil. In addition, overweight individuals are often leptin-resistant and develop impaired vasodilation resulting from superoxide-mediated scavenging of nitric oxide. Therefore, the reported antioxidant and weight loss properties of omega 3 supplementation may greatly benefit overweight individuals.
ContributorsAlanbagy, Samer (Author) / Sweazea, Karen (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2014
Description
Background: Twenty-four hour urinary sucrose and fructose (24uSF) has been developed as a dietary biomarker for total sugars intake. Collection of 24-h urine is associated with high costs and heavy participant burden, while collection of spot urine samples can be easily implemented in research protocols. The aim of this thesis is to investigate the utility of uSF biomarker measured in spot urine. Methods: 15 participants age 22 to 49 years completed a 15-day feeding study in which they consumed their usual diet under controlled conditions, and recorded the time each meal was consumed. Two nonconsecutive 24-hour urines, where each urine void was collected in a separate container, were collected. Four timed voids (morning, afternoon, evening, and next day) were identified based on time of void and meal time. Urine samples were measured for sucrose, fructose and creatinine. Variability of uSF excretion was assessed by coefficient of variation (%CV) and variance ratios. Pearson correlation coefficient and multiple linear regression were used to investigate the association between uSF in each timed void and corresponding 24uSF excretion. Results: The two-day mean uSF was 50.6 mg (SD=29.5) for the 24-h urine, and ranged from 4.5 to 7.5 mg/void for the timed voids. The afternoon void uSF had the lowest within-subject variability (49.1%), and lowest within- to between-subject variance ratio (0.2). The morning and afternoon void uSF had the strongest correlation with 24-h uSF for both mg/void (r=0.80 and r=0.72) and mg/creatinine (r=0.72 and r=0.67), respectively. Finally, the afternoon void uSF along with other covariates had the strongest predictive ability of 24-h uSF excretion (mg/void) (Adjusted R2= 0.69; p=0.002), whereas the morning void had the strongest predictive ability of 24-h uSF excretion (mg/g creatinine) (adjusted R2= 0.58; p=0.008). Conclusions: The afternoon void uSF had the most favorable reproducibility estimates, strong correlation with 24uSF excretion, and explained greatest proportion of the variability in 24uSF. USF in mg/void may be better to use than uSF in mg/g creatinine as a biomarker in spot urine. These findings need to be confirmed in a larger study, and in a study population with a wide range of sugars intake.
ContributorsAverill, Annalisa (Author) / Tasevska, Natasha (Thesis advisor) / Shepard, Christina (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2018
Description
Food waste is gaining considerable attention from researchers in terms of its sources, its causes, and its potential effects on the environment, economy, and population health. To date, few instruments exist that allow researchers to measure food waste at the household level in reliable ways. This study aimed to assess the reliability of a newly developed self-assessment tool to measure household food waste, among participants living in Mexico. The survey tool consisted of 11 items which ask participants (N = 22) to estimate the amount of food per category that generally gets thrown away instead of eaten in the average week. Two tests of reliability were conducted, including Cronbach's Alpha for test-retest reliability, and Intra-class Correlation for internal reliability. Results varied across food categories evaluated by individual items. Items related to fresh fruit and bread products did not show reliability when testing for internal reliability or test-retest reliability. Fresh vegetables, meat and poultry products, meat alternative products, fish and seafood products, leftovers, and shelf stable foods were shown to be reliable when testing Cronbach's alpha and ICC. However, dairy products, eggs and frozen foods were inconclusive when testing for reliability. The study suggests future testing with larger sample sizes should be conducted to demonstrate reliability of the food waste self-assessment tool.
ContributorsLeone, Bryanna (Author) / Wharton, Christopher (Thesis advisor) / Shepard, Christina (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2022
Description
Low water intake and underhydration are public health issues that may increase risk for diseases such as Type 2 Diabetes Mellitus. Studies suggest that high vasopressin (AVP) levels associated with low water intake may contribute to hyperglycemia. This study explored the physiological system by which AVP impairs glucose regulation through a single-blind randomized, counterbalanced, crossover design. This is a pilot and feasibility study of AVP infusion at increasing incremental rates, which was completed to determine the rate of infusion for the cross-over study. Participants completed a control and experimental trial. The experimental trial included a 3-hour AVP infusion and a 2-hour euglycemic-hyper insulinemic clamp at the end of the first hour versus control of 0.9% sodium chloride replacing AVP. In both trials, blood samples were taken every 5 minutes to measure glucose, as well as 7 other time points of insulin infusion. Two participants completed the pilot (47.5±3.5 years, 172.5 ±7.5cm, 82.5±17.7kg, 27.5±3.5 kg/m2, 5.1±0.64% HbA1c), and 3 participants completed the cross-over study (49±1.7 years, 173.7±6.7cm, 80.4±150kg, 26.5±3.2kg/m2, 5.3±0.2% HbA1c), all females. The rate of AVP infusion for the cross-over study was 12.5 mU/min. Compared to the control, the AVP trial blood glucose trended higher towards the end of the experiment, as did glucose metabolism, plasma osmolality, and plasma volume. Blood pressure was slightly higher in the AVP trial versus the saline, while plasma sodium and potassium levels did not differ. Total plasma protein seemed higher in the saline trials than in the AVP trials. This study supports the notion that increased levels of vasopressin over time may increase blood glucose. This could lead to supplementation of type 2 diabetes interventions with increased water intake.
ContributorsAcri, Emily Suzanne (Author) / Kavouras, Stavros (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2024