Master of Public Health / Kinesiology / David Dzewaltowski / Background: Childhood obesity represents a major public health problem. Increasing public and political attention has been directed towards the role of child-directed food advertising in the growth of childhood obesity. As a potential solution, scientists have begun to focus on children’s responses to advertising and on how parents can potentially modify or reduce advertising effects. This study explored the impact of food advertising on parent behavior and children's food choice and how these potential effects are moderated by household socioeconomic status (SES). Methods: Fifty-eight parent-child dyads (ages of 4-6) participated in a true experimental design where half the sample was randomized to be exposed to advertising and categorized as low income or higher income (qualified for free and reduced lunch, n = 11; paid, n = 18) and half was randomized into a control condition (qualified for free and reduced lunch, n = 12; paid, n = 17). Parents completed a questionnaire, viewed a cartoon with energy dense (ED) food commercials or control commercials with their children, and children subsequently choose either an energy dense food or a fruit or vegetable. Throughout the experiment parent and child behavior was videotaped. Binary logistic regression was conducted to examine the impact of advertising and household SES on parent behaviors and children’s food choice. Results: Advertisements had no effect on food choice. More low-income children chose a fruit or vegetable over an energy dense food (OR = 5.8), regardless of whether or not they were exposed to advertising (p<.05). Parents were more likely to be uninvolved in mediating children’s food choice when they were not exposed to advertising. Parents were also less likely to agree to energy dense foods after being exposed to energy dense food advertising compared to control advertising. However, SES moderated the advertising-parental practice effect for parental agreement to an ED food. After exposure to food advertising, more low-income parents agreed to an energy dense food compared to higher income parents. (p<.05). Conclusion: This study has demonstrated a link between advertising exposure and parenting behavior. Results suggest that this relationship may be moderated by socioeconomic status. This encouraging result may indicate that low-income parents are unaware of the various ways advertising could influence their children. Thus, future attempts should be made to investigate whether interventions that target parent-child communication strategies may empower parents to effectively curb unwanted advertising effects in children.

Doctor of Philosophy / Department of Anatomy and Physiology / David C. Poole / The overall aim of this dissertation is to better understand the mechanisms determining skeletal muscle oxygen delivery-utilization matching in health and disease. Emphasis is directed toward the role of nitric oxide (NO) bioavailability in modulating muscle microvascular oxygenation (PO2mv; the sole driving force for blood-myocyte oxygen flux) during transitions in metabolic demand. The first investigation of this dissertation (Chapter 2) demonstrates that alterations in NO bioavailability have a major impact on skeletal muscle PO2mv kinetics following both the onset and cessation of contractions. Specifically, increased NO levels (via the NO donor sodium nitroprusside; SNP) elevates whereas reduced NO levels (non-specific NOS inhibition with NG-nitro-L-arginine methyl ester; L-NAME) diminishes muscle PO2mv at the onset and during recovery from contractions in the spinotrapezius muscle of healthy young rats. Consistent with these results, inhibition of the neuronal NO synthase isoform (S-methyl-L-thiocitrulline; SMTC; Chapter 3) reveals alterations in NO-mediated regulation of skeletal muscle PO2mv with advanced age that likely contribute to exercise intolerance in this population. In Chapter 4 we observed that pronounced oxidative stress is implicated in these pathological responses seen in aged and diseased states. Transient elevations in the oxidant hydrogen peroxide to levels seen in the early stages of senescence and cardiovascular diseases promote detrimental effects on skeletal muscle contractile function (i.e., augmented oxygen cost of force production). Chapter 5 demonstrates that endurance exercise training improves skeletal muscle microvascular oxygenation (i.e., greater PO2mv and slower PO2mv kinetics) across the metabolic transient partly via enhanced NO-mediated function in healthy young individuals. These data carry important clinical implications given that exercise training may ameliorate NO-mediated function, muscle microvascular oxygenation deficits and consequently exercise intolerance in aged and diseased populations. In conclusion, alterations in NO bioavailability have a major impact on the dynamic balance between skeletal muscle oxygen delivery and utilization (i.e., PO2mv kinetics) in health and disease. While advanced age or the predations of disease impair considerably skeletal muscle microvascular oxygenation, exercise training-induced adaptations on the oxygen transport system constitute a non-pharmacological therapeutic intervention potentially capable of mitigating these microcirculatory deficits.

Master of Public Health / Department of Diagnostic Medicine and Pathobiology / M. M. Chengappa / Rabies is the most deadly disease on earth and has a 99.9% human fatality rate. Rabies kills 61,000 humans annually and results in an economic burden of $124 billion USD annually. Each day 3.3 million people live with the risk of rabies. It is estimated that 95% of human rabies cases are a result of coming in contact with an infected canine, majority of these cases being children 15 years and younger. It is estimated that 1 person every 8 minutes dies of rabies. Rabies is a highly neurotropic disease which attacks the brain and central nervous system. Once clinical symptoms are presented, death is invariably the outcome as no cure exists for rabies. Rabies is 100% preventable in humans by proper wound management and proper administration of prophylaxis. Rabies can be adequately controlled in animal populations by contraception and animal rabies vaccine efforts. Whilst it is known that rabies can be prevented in humans and controlled in animal populations, further scientific efforts are still warranted to fully understand this deadly virus so that a cure can one day be discovered. As human and animal populations continue to grow, so does the cost and burden of this horrific disease. As a result, the importance of prophylaxis and passive immunity are critical in the event of medically managing an exposure, and preventing exposures. The World Health Organization has defined global recommendations for individuals and animals who have received prophylaxis to be adequately protected. Measuring this protection is performed using a variety of approved testing methodologies, virus-neutralizing assays and antigen-binding assays. Whilst the WHO recommendations were defined from clinical studies performed with virus-neutralizing assays, the assumption that these recommendations are suitable for the antigen-binding assays is inaccurate. The testing methodologies, virus-neutralization and antigen-binding, share similarities, as they are measuring an immune response to the rabies virus. However; enough differing characteristics are presented such that exact comparisons cannot be made. Establishing the same standards and recommendations for both testing methodologies will never be sufficient.

Master of Public Health / Department of Human Nutrition / Sandra B. Procter / Family meals and meals with caregivers can be sources of social support. Current literature indicates that social support is important for physical and psychological health and well-being. There has been no published research looking at the role of communal meals in collegiate dining centers as sources of social support. This study investigated the possibility that communal meals in a collegiate dining center and eating with other people in these settings may be related to perceived social support, academic success, frequency of family meals, and/or degree of involvement in college extracurricular activities. To investigate these relationships, first-year Kansas State University students living in the residence halls of the Derby Complex (Ford, Haymaker, Moore, and West Halls) were administered a survey about dining center usage habits. The survey included the previously tested Interpersonal Relationship Inventory Short Form by V.P. Tilden (n.d.) as a measure of perceived social support. Participants granted access to their first semester Kansas State University grade point average and semester dining center usage data. Surveys were completed online (n=216) and in paper format (n=89) for a total of 303 participants. There was no significant difference between the demographics of those that completed the online versus paper formats of the survey. Therefore, the online and paper formats of the survey were analyzed together. The data were analyzed for all participants and for males (n=94) and females (n=209) separately. Results revealed multiple significant relationships (p<0.05). Results related to grade point average and perceived social support revealed a significant positive relationship between frequency of eating in the dining center and grade point average for all participants combined. This relationship was also noted for males and females analyzed separately. Frequency of eating with others was found to be significantly positively correlated to perceived social support score for all participants combined, and for males and females analyzed separately. Frequency of eating with others was significantly positively correlated with grade point average for males alone and females alone, but not all participants combined. Further research is needed to determine if the relationships are causal and if so, the direction of causality in the relationships.

Master of Science / Department of Clinical Sciences / Thomas Schermerhorn / Tonicity is property of a solution that is defined as the total effective (impermeable) osmole concentration that drives fluid movement across a semipermeable membrane via osmosis. Tonicity is related to but distinct from solution osmolality, which is a summation of all solute concentrations, regardless of the solute membrane permeability. In the mammalian body, tonicity is tightly regulated at both a cellular and systemic level; tonic derangements cause rapid change in cell and tissue volume leading to significant dysfunction. Input from the central nervous, circulatory, endocrine, gastrointestinal, and urinary systems are integral to osmoregulation, so many diseases in veterinary medicine are associated with tonicity disorders. However, because the homeostatic mechanisms that control tonicity overlap with those regulating electrolyte and acid-base balance as well as hydration and vascular volume, tonic consequences of disease can be difficult to isolate. Understanding of disease-associated changes in tonicity is further complicated by the fact that the tonic contributions of many solutes that accumulate in disease are unknown. Additionally, direct assessment of tonicity is difficult because tonicity is not just a physiochemical property, but it implies a physiologic effect. Thus, simple summation of osmole concentrations is an inadequate measurement of tonicity. The following report includes three studies investigating various aspects of tonicity as it applies to veterinary patients. Chapter 2 reports a study that examines the tonic effects of ketoacids and lactate using two different in vitro red blood cell assays. Results demonstrated that the ketoacids, beta-hydroxybutyrate and acetoacetate, behave as ineffective osmoles while the tonic behavior of lactate is variable, implying a more complex cellular handling of this anion. Two additional studies examine whether the mean corpuscular volume difference (dMCV) is a novel clinical marker for hypertonicity in dogs. Results of separate retrospective (Chapter 3) and prospective (Chapter 4) studies provide evidence that dMCV is a useful clinical marker for hypertonicity in dogs.

Master of Science / Department of Grain Science and Industry / Sajid Alavi / The objective of the study was to investigate extrusion as an alternative processing method and grain sorghum as a viable substitute for corn in fortified blended foods (FBFs) used in nutrition and food assistance programs around the world. In the first part of this study, sorghum-soy blend (SSB), corn-soy blend (CSB) and whole corn-soy blend (WCSB) were developed using extrusion and compared with traditional CSB13 for physico-chemical and sensory properties. After milling of extrudates, average particle size (PS) ranged between 341-447 microns, with 78-85% below 600 microns. In general, Bostwick flow rates (VB=12-23 cm/min) of rehydrated blends (11.75% solids) were within standard specifications but higher than CSB13. Descriptive sensory analysis indicated that the sorghum-based rehydrated blends were significantly less lumpy and had a more uniform texture as compared to corn-based blends and CSB13. In the second part, the impact of decortication level and process conditions was investigated with respect to sorghum-based extruded blends. Degree of gelatinization of the whole sorghum-soy blend (WSSB) and decorticated sorghum-soy blend (DSSB) extrudates ranged from 93-97%. Expansion ratio (ER=3.6-6.1) was correlated with specific mechanical energy input (SME=145-415 kJ/kg; r=0.99) and average particle size after milling (PS=336-474 microns; r= -0.75). Rehydrated blends at 20% solids concentration provided recommended energy density (0.8 kcal/g) for FBFs. Bostwick flow rates had high correlation (r = -0.91) with pasting data (final viscosity) obtained using rapid visco analyzer (RVA). Addition of oil (5.5%) prior to extrusion was also studied, and resulted in process instabilities and also lower shelf-life as determined via descriptive sensory analysis (rancid and painty attributes) and gas chromatography-mass spectroscopy (hexanal, heptenal and octanal concentrations). In conclusion, extruded sorghum-soy blends met standard specifications for energy density and consistency (Bostwick flow rate), and were superior in some aspects as compared to extruded corn-soy blends and traditional corn-soy blends (CSB13). Relationships between extrusion mechanical energy input, expansion, particle size after milling and consistency of rehydrated blends were established. Consistency of the rehydrated blends is an extremely important criterion as it affects the ease of ingestion by target consumers (children below 5 years, in this case).