published_or_final_version / Biological Sciences / Master / Master of Philosophy

The objectives were to investigate the effects of chromium (III) picolinate (CrPic; up to 2,000 ppb of Cr) on growing pigs subjected to a variety of stressors including thermal, immune, or dietary stress and to examine the effects of CrPic on steroidogenesis from adrenocortical cells. In the thermal stress study, high ambient temperature caused reduced weight gain and feed consumption (P andlt; 0.01), and low ambient temperature caused increased feed intake and feed:gain (P andlt; 0.01). However, these effects were not moderated by CrPic, and respiratory rate, plasma cortisol, or plasma glucose were unaffected by CrPic. In the immune stress study, pigs challenged with lipopolysaccharide (LPS) lost 951 g during 12 hours post injection, while the phosphate buffer saline (PBS) injected group gained 170 g (P andlt; 0.001). The LPS group showed higher rectal temperature (P andlt; 0.05), higher respiratory rate (P andlt; 0.05), greater plasma cortisol (P andlt; 0.001), and lower plasma glucose (P andlt; 0.05) than the PBS group. These effects were not ameliorated by CrPic. In the dietary stress study, pigs fed the high-fat diet (HFD) gained weight faster (P andlt; 0.05), consumed less feed (P andlt; 0.001), and had lower feed:gain (P andlt; 0.001). Plasma insulin concentration on d 14 decreased with CrPic (P andlt; 0.05) in a linear manner (P = 0.05). Consumption of the HFD resulted in increases of slaughter weight, perirenal fat, and back fat measurements (P andlt; 0.01). The CrPic resulted in linear reductions of carcass weight, last rib fat, last lumbar fat and average backfat (P andlt; 0.10). The effects of CrPic on carcass fat measurements were more significant in barrows than gilts. In the adrenocortical cell study, forskolin stimulated cortisol and DHEAs secretion from H295R cells. CrPic inhibited aspects of steroidogenesis in agonist-stimulated adrenocortical cells. Overall, dietary CrPic was unable to moderate the stress related effects due to high ambient temperature, low ambient temperature, or an endotoxin challenge. However, CrPic attenuated effects of HFD, mainly on body fat accretion of pigs, especially in barrows, and CrPic inhibited steroidogenesis in stimulated adrenocorticoid cells.

Dietary saturated fat intake contributes to diabetes and cardiovascular disease, as shown in numerous animal and human studies. However, the hypothesis that stearic acid, a saturated fat, has beneficial effects on these conditions has not been adequately tested. Leptin receptor deficient mice (db/db) and wild-type mice were fed either chow or a high fat diet enriched in either stearic acid or oleic acid for ten weeks. The progression of diabetes was evaluated with blood glucose, insulin, and metabolic parameter measurements. At the conclusion of the study, pancreatic islet organization was examined, and blood, liver and feces were assayed for fatty acid content. The stearic acid enriched diet prevented increases in blood glucose levels independently of weight loss in db/db mice compared to an oleic acid or chow diet. Diabetic mice fed stearic acid maintained insulin responsiveness and pancreatic islet organization compared to the db/db mice fed chow and oleic diets. The islet organization of the stearic acid fed mice did not change over the course of the study and was similar to that of wild-type mice fed the same diet. Conversely, diabetic mice fed oleic acid and chow diets had decreased insulin responsiveness and disorganized islets. Stearic acid fed db/db mice had high fecal fat content and caloric intake calculations indicated low absorption of this fat. Switching to stearic acid after prolonged hyperglycemia had a rescue effect on blood glucose levels. After feeding diabetic and wild-type mice standard chow diets for 6, 8, and 10 weeks to establish hyperglycemia, mice switched to a high fat diet enriched in stearic acid, but not one enriched in oleic acid diet, had significant reductions in blood glucose levels. The ability of a stearic acid enriched high fat diet to slow the progression of diabetes and reverse hyperglycemia in db/db mice argues that risks and benefits of fats in the diet depend on the chemical structure, rather than the chemical class, of fats ingested. The beneficial effect of stearic acid appears to be associated with a decreased absorption of dietary fat.

The goal of this dissertation research was to describe the relationships among psychosocial variables, physical activity and physical fitness, and biological measures indicative of cardiovascular health in Mexican American male adolescents using a biobehavioral model. One aim of the research was to describe the predictive relationship of psychosocial variables, perceived benefits, perceived barriers, self-efficacy, and interpersonal influences, on physical activity and physical fitness. A second aim described the predictive relationship among physical activity and physical fitness and the amount of body fat and levels of biological markers indicative of endothelial function in this population. Study participants were 28 Mexican American male adolescents ages 15-19. Psychosocial variables were assessed using instruments developed for adolescents by Pender. Physical activity was measured by a 3-day accelerometer recording of activity counts while physical fitness was measured with cycle ergometry withVO2 max. Biologic measures indicative of cardiovascular health included serum leptin, CRP, adiponectin. Fat mass was assessed using BMI and DEXA scans. Findings demonstrated partial support for the model. Psychosocial variables predictive of physical fitness included perceived benefits of action and interpersonal influences. Perceived benefits of exercise significantly predicted physical fitness, explaining 50% of the variance in physical fitness scores while exercise norms, a measure of interpersonal influence, predicted 17% of the variance. Self-efficacy did not meet criteria as a mediating variable; it directly predicted physical activity. Physical activity predicted 15% of the variance in body fat measured as BMI percentile. Physical fitness predicted Leptin levels accounting for 23% of the variance. Physical fitness also predicted 51% of the variance related to the DEXA-derived body fat measurement and 18% of the variance related to BMI. Additional trends were identified including lack of parental support for exercise. Although the study participants reported high acculturated levels, language spoken at home indicated that the family was less acculturated which may have accounted for the lack of parental support. Higher acculturation levels were also significantly associated with increased perceived benefits of action and higher BMI levels. In conclusion, this study suggests that selected psychosocial variables including interpersonal influences should be considered in designing research with Mexican American adolescent males. In addition results suggest that objectively obtained measures of physical fitness and activity are in part predictive of measures of endothelial function and body fat.

The composition of the diet has been recently researched as an important factor in controlling excess body fat, and thus obesity. Along with dietary modifications, it has been stressed to incorporate behavior modification and daily physical activity to promote weight loss. A comprehensive program incorporating all three components is the suggested treatment for long term weight maintenance. This study investigated a 12 week low dietary fat education program including behavior modification and physical activity to promote weight loss in the abdominally obese. There were eight experimental subjects and four controls. Measurements assessed were height, weight, percent body fat, body mass index, waist/hip ratio, ideal body weight, daily caloric intake, percent dietary fat intake, percent saturated fat intake, saturated fat gram intake, physical activity assessments and resting metabolic rate. Results showed significant differences between the experimental and control groups for calorie intake, body weight, ideal body weight and saturated fat gram intake at post-intervention. Percent of dietary fat intake decreased from baseline to follow-up in the experimental group, but did not reach significance. There was a 33% decrease in saturated fat gram intake from baseline to follow-up in the experimental group. A significant decrease in daily caloric intake occurred in the experimental group from baseline to post-intervention. The decrease in body weight could not be directly correlated to dietary fat intake, although they did have a tendency to move in the same direction. These data suggest the weight management program in this study was successful at decreasing body weight, daily caloric intake, dietary fat intake and saturated fat intake.The qualitative interview revealed obstacles faced by the subjects. The most common difficulties in adhering to the program included time constraints, travel, lack of a structured physical activity component, social pressures triggering eating behavior, feeling of guilt when prioritizing time for oneself and lack of continued support and education through class sessions. Individual motivational factors existed. Therefore, personalized attention and a continued support system would be beneficial as part of the treatment program for success in changing lifestyle behaviors.In conclusion, this data suggest an educational program encouraging decreased dietary fat intake, behavior modification and increased daily physical activity without a calorie controlled plan can promote weight management in the abdominally obese. / Institute for Wellness

The research within this thesis sought to determine the ability of various animal derived fats and plant derived oils to support the survival of several pathogenic cocktails over a multitude of storage times. The Salmonella study explored the survival rate of a four strain Salmonella cocktail in beef tallow, pig lard, duck fat, coconut oil, and extra virgin olive oil over seven days at 26˚C and 37˚C storage. The animal fats and the coconut oil supported the survival of the bacteria until the conclusion of the study. The Shiga-toxin producing Escherichia coli study explored the survival rate of a five strain STECs cocktail in extra virgin olive oil over seven days at 26˚C and 37˚C storage. The two Listeria studies explored the survival rate of a four strain Listeria monocytogenes cocktail in extra virgin olive oil over several time periods with different frequencies of sample mixing. In vitro, all genuses showed a 2.5-log cfu/mL to ≥ 7-log cfu/mL reduction in the extra virgin olive oil by the conclusion of the experiments. Extra virgin olive oil was then applied to cooked pork tenderloin, cheddar cheese snack squares, and turkey lunchmeat in hopes of inhibiting the L. monocytogenes cocktail. No reduction was observed.

Sirtuins (SIRT) regulate the transcription of various genes involved in the development of diet-induced obesity and chronic disease; however, it is unknown how they change acutely following a high-fat meal. The purpose of this study was to determine the effect of a high-fat meal (65% kcals/d; 85% fat recommendation), on SIRT1-7 mRNA expression in blood leukocytes at 1, 3, and 5-h post-prandial. Men and women (N=24) reported to the lab following an overnight fast (>12H). Total RNA was isolated and reverse transcribed prior to using a Taqman qPCR technique with 18S rRNA as a normalizer to determine SIRT1-7 mRNA expression. An additional aliquot of serum was used to measure triglycerides. Data was analyzed using a RM ANOVA with P<0.05. Triglycerides (P<0.001; 124%) peaked at 3-h. SIRT 1 (P=0.004; 70%), and SIRT 6 (P=0.017; 53%) decreased expression at 3-h. SIRT4 (P=0.024) peaked at 5H relative to baseline (70%) and 3-h (68%). To our knowledge, this is the first study to report that consumption of a high-fat meal transiently alters SIRT mRNA expression consistent in a pattern that mirrors changes in serum triglycerides. Decrease in expression of SIRT1 and SIRT6 combined with an increased SIRT4 would be consistent with an increase in metabolic disease risk if maintained on a chronic basis.

Background.Studies have shown that low-grade chronic inflammation affect muscle mass negatively. Theimpact of inflammation in grip strength is not yet investigated. Existing studies are made on a few populations.This study aims to describe how inflammation, grip strength and muscle mass looks in agroup of 52-year-old men and women and to examine the differences between the sexes.Another aim is to investigate the correlations between low-grade chronic inflammation (n =32) and muscle mass (n = 23) and grip strength (n = 30).Method Data from an ongoing study were analyzed with a non-experimental descriptive, comparativeand correlating design. Lean muscle mass was calculated by subtracting the percentage of fatfrom weight. Grip strength was measured by Jamar dynamometer. CRP as inflammationparameter through blood-samples. Results The populations measured levels was consistent with current reference values för healthyindividuals. Tendencies to positive correlation between CRP and muscle mass could be seenfor both men and women. For men there were tendency towards positive correlation betweenCRP levels and grip strength, while tendency to negative correlation for women. Women hadhigher CRP levels compared to men. Men had higher levels of muscle mass and grip strength. Conclusion No conclusions could be drawn regarding the effect of low-grade chronic inflammation effectin fat-free mass and grip strength. The study has highlighted the need for further research inthe field.

Doctor of Philosophy / Department of Kinesiology / Craig A. Harms / The overall aim of this dissertation was to determine the impact of lifestyle (i.e. habitual and acute physical activity and diet), age, and sex on systemic and airway inflammation and oxidative stress. In study 1 (Chapter 2) we examined the impact of habitual physical activity level on the post-prandial airway inflammatory response following an acute bout of moderate intensity exercise. Results indicated that the mean exhaled nitric oxide (eNO; marker of airway inflammation) response increased for all groups at two hours post high-fat meal (HFM) (~6%) and returned to baseline by four hours post-HFM. However, there was a varying eNO response from baseline to four hours in the group that exercised in the post-prandial period compared to the group that remained sedentary. These findings suggest airway inflammation occurs after a HFM when exercise is performed in the post-prandial period, regardless of habitual physical activity level. In study 2 (Chapter 3) we investigated the post-prandial oxidative stress response to meals of varying calories and fat. Specifically, we assessed the post-prandial airway and systemic 8-isoprostane (a marker of oxidative stress) responses to meals with moderate-fat (8.5 kcal/kg of bodyweight) and high-fat content (17 kcal/kg of bodyweight) from baseline to six hours post-meal in a randomized crossover design. This study revealed that systemic 8-isoprostane increased from baseline to six hours post-meal (38.3%), but there was no difference between the moderate-fat meal (MFM) and HFM conditions. There were no changes in airway 8-isoprostane from baseline to six hours post-MFM or HFM, or between the MFM and HFM conditions. Lastly, in study 3 (Chapter 4), we were interested in examining 8-isoprostane responses in older adults, since 8-isoprostane has been reported to increase with age. Previous research also suggests that older women (OW) and older men (OM) have differences with regard to prevalence and severity of late-onset asthma. In this study, we sought to determine whether the airway 8-isoprostane response to a strenuous bout of exercise was different in OW compared to OM. A secondary aim was to determine whether post-exercise 8-isoprostane generation was correlated with decrements in lung function. Our results showed that the generation of 8-isoprostane from pre- to post-exercise increased ~74±77% in OW and decreased ~12±50% in OM. The decrease in 8-isoprostane generation was not correlated with improvements in lung function from pre- to post-exercise. These findings collectively contribute to the literature by enhancing our understanding of the impact of lifestyle factors, age and sex on modifying and potentially mitigating the risk of developing chronic diseases.

In the present thesis we analyze different types of additive decompositions of homogeneous polynomials. These problems are usually called Waring-type problems and their story go back to the mid-19th century and, recently, they received the attention of a large community of mathematicians and engineers due to several applications. At the same time, they are related to branches of Commutative Algebra and Algebraic Geometry. The classical Waring problem investigates decompositions of homogeneous polynomials as sums of powers of linear forms. Via Apolarity Theory, the study of these decompositions for a given polynomial F is related to the study of configuration of points apolar to F, namely, configurations of points whose defining ideal is contained in the ``perp'' ideal associated to F. In particular, we analyze which kind of minimal set of points can be apolar to some given polynomial in cases with small degrees and small number of variables. This let us introduce the concept of Waring loci of homogeneous polynomials. From a geometric point of view, questions about additive decompositions of polynomials can be described in terms of secant varieties of projective varieties. In particular, we are interested in the dimensions of such varieties. By using an old result due to Terracini, we can compute these dimensions by looking at the Hilbert series of homogeneous ideal. Hilbert series are very important algebraic invariants associated to homogeneous ideals. In the case of classical Waring problem, we have to look at power ideals, i.e., ideals generated by powers of linear forms. Via Apolarity Theory, their Hilbert series are related to Hilbert series of ideals of fat points, i.e., ideals of configurations of points with some multiplicity. In this thesis, we consider some special configuration of fat points. In general, Hilbert series of ideals of fat points is a very active field of research. We explain how it is related to the famous Fröberg's conjecture about Hilbert series of generic ideals. Moreover, we use Fröberg's conjecture to deduce the dimensions of several secant varieties of particular projective varieties and, then, to deduce results regarding some particular Waring-type problems for polynomials. In this thesis, we mostly work over the complex numbers. However, we also analyze the case of classical Waring decompositions for monomials over the real numbers. In particular, we classify for which monomials the minimal length of a decomposition in sum of powers of linear forms is independent from choosing the ground field as the field of complex or real numbers.