Glucocorticoids Induce Molecular and Phenotypical Changes in Visceral Adipose Tissue When Consuming a High Fat Diet

Visceral adipose tissue (VAT) physiology is negatively affected by chronic glucocorticoid (GC) usage, and is exacerbated by a Western diet. However, the impact of omega-3 supplimentation into a Western diet, during chronic GC usage, remains unknown. Therefore, we determined the impact of both diets ( Western vs omega-3 supplimented) in conjunction with chronic GCs, on VAT physiology. Sixty-four male C57BL/6 mice (n=8-16/group) were subjected to 4-weeks of dietary intervention (high fat lard [HFL] vs. high fat fish oil [HFO], with or without prednisolone [40mg/kg/m2] daily). We hypothesized that omega-3 supplimentation would protect VAT physiology from chronic GC-induced negative effects. Overall, both HFO groups gained less body weight, displayed less VAT and smaller adipocytes, retained a greater percentage of M2-polarized macrophages, and exhibited beneficial alterations in gene expression as compared to both HFL groups. Our data indicate that VAT physiology is protected by an increase in dietary omega-3s, irrispective of GC usage

Taphonomy and sedimentology of two Miocene vertebrate fossil sites on Fort Polk, Louisiana

The discovery of a terrestrial mammalian fauna in the Miocene deposits on Fort Polk, Louisiana, fills a geographic gap in the Gulf Coast paleontological framework, but the provenance of the fossils, nature of the depositional environments, and relationships between the sites is still debated. This is especially true for the TVOR site cluster. TVOR SE has a mixture of marine and terrestrial vertebrates in association with a partly dissolved, in situ bed of articulated oyster shells, which stands in contrast to the fully terrestrial and freshwater assemblage at TVOR, and the indeterminate site TVOR S. Although limited outcrop may bias the observed fossil assemblages, it is thought that the differing characteristics of the sites are related to changing depositional environments. Taphonomic and geologic data were integrated to create a more complete picture of the paleoenvironmental factors contributing to the formation of the fossil sites. One core each was collected at TVOR S and TVOR SE, and these were studied along with a core previously collected at TVOR site. Magnetic susceptibility (MS) work on the cores suggested correlation between the TVOR S and TVOR SE sites, and possible correlation between TVOR S and TVOR. MS data indicated marine influence at all three sites, including TVOR, which previously had been considered fully terrestrial. Heavy mineral analysis was unfruitful regarding the provenance of the sites. Identified, curated fossils from the sites were assigned to bone dispersal groups to assess the degree of sorting in the fossil assemblages, and it was discovered that the vast majority of both macro- and micro-vertebrate fossils fall into Groups I and II, indicating that the fossil assemblages are the result of transport into the sites rather than attrition of local biota. The geological, geophysical, and paleontological records of the sites give a picture of a quiet, distal, setting just beginning to reflect environmental changes spurred by local and global geologic processes

Representative Government: An Evaluation of Single-Party Dominance in the State of Arkansas

Studying the opinion-policy link in the state of Arkansas can determine if the state has had a representative governing body. The state, like many others, has a history of single-party dominance politics, and this study seeks to understand the conditions for policy congruence under one-party rule. Specifically, this research focuses on the past two decades of Arkansas politics, wherein the state’s legislature experienced a partisan shift from the Democratic Party to the eventual single-party dominance of the Republicans. Using data from the Arkansas Poll and the Arkansas State Legislature to analyze multivariate OLS regression models, this study investigates factors that account for policies passed by the state legislature that are congruent with the state’s public opinion. Overall, this study finds that policies were most congruent with public opinion under Democratic single-party dominance, yet where party competition remained high, influencing the party to be more accountable to its right-leaning constituents. Public policy is incongruent with public opinion under Republican years of single-party dominance, which occurs during a low competitive political environment. This indicates that single-party dominance flourishes when it has an electoral advantage, giving parties less incentive to adhere to public interests and greater political room to pass more extreme policies that do not necessarily align with what the public may want. These findings have important implications for the current state of Arkansas politics. Though Republicans may have control of both the executive and legislative branches, 2022 has the potential to be an election year that shakes up Arkansas politics as more Democratic candidates are running for office, possibly increasing the policy congruence between the state legislature and public opinion

Implications of diet-induced obesity on metabolic and immune homeostasis: the role of the mesenteric lymph nodes

Includes bibliographical references.2020 Summer.Obesity is a major public health crisis among adolescents and adults. The development of obesity is associated with several comorbidities as a result of underlying systemic chronic inflammation, the culmination of which increases one’s risk for chronic and infectious disease. Excessive accumulation of visceral adipose tissue is shown to confer the greatest disease risk. This is primarily due to inherent depot differences, namely proximity to and a shared blood supply with the liver and gastrointestinal (GI) tract. Recent work demonstrates the considerable influence gut physiology has over both local and systemic homeostasis, as GI diseases such as inflammatory bowel disease are associated with metabolic derangements characteristic of obesity. While the mechanisms that mediate this inter-organ crosstalk continue to be elucidated, several studies suggest that inflammation originating from the gut triggers these broad metabolic and immunologic changes found in obesity. Previous work from our lab has demonstrated that high-fat diet (HFD) induced obesity results in mesenteric lymph node (MLN) fibrosis, which was associated with a localized impairment in immune function. MLNs, located within mesenteric adipose tissue (MAT) surrounding the GI tract, constitutively monitor the mesenteric adipose depot and draining sections of the small and large intestines, serving as critical inductive sites for adaptive immune responses. Subsequently, they are essential for overall tissue maintenance and protection. Hence, further study into the role of the MLNs in obesity-associated pathology is an important area of research. The goals of this dissertation research were to 1) examine the relationship between MLNs and GI inflammation on metabolic outcomes, and 2) characterize immunologic changes associated with models of chronic inflammation. To investigate the above-mentioned, we conducted four separate preclinical studies utilizing mouse models of diet-induced obesity, MLN cauterization, and dextran sulfate sodium (DSS) induced GI inflammation. In the first study (Chapter 2), we examined the contribution of the MLNs on disease pathology associated with HFD-induced obesity. We found that MLN dysfunction, either as a result of surgical manipulation or obesity-induced fibrosis, led to metabolic dysfunction. Furthermore, that functional MLNs are needed for the full restorative effects of Pirfenidone treatment. In the second study (Chapter 3), we examined the effect of chronic low-dose DSS induced GI inflammation, independent of diet and obesity, on metabolic and immune function. We found that non-obese mice treated with DSS had a modest reduction in total body weight and MAT mass yet showed substantial alterations in tissue immune cell populations and frequencies. These adaptations occurred without a concurrent change in glucose homeostasis. Finally, in the third study (Chapter 4) we characterized immunologic parameters within a normal weight and obese human population, free of disease, through the ex vivo challenge of peripheral blood mononuclear cells (PBMCs) with the T lymphocyte mitogen Concanavalin A (ConA). We found that PBMCs isolated from obese adults had a modest increase in cell proliferation and IFNγ secretion upon stimulation within ConA relative to their normal weight controls. Additionally, we found a distinct expansion of CD4+CD8+ T cells, CD16+ monocytes, and NK cells within ConA stimulated PBMCs from obese donors. Collectively, these studies provide evidence that 1) the MLNs are critical for metabolic homeostasis as their dysfunction exacerbates features of HFD-induced obesity; 2) chronic GI iv inflammation, independent of diet and obesity, can reshape the immune milieu without altering glucose homeostasis; and 3) obesity distinctly alters the PBMC response to acute ex vivo challenge as compared to that of normal weight individuals. Future studies should further elucidate mechanisms of crosstalk between the immune system, MLNs, and GI tract on metabolic homeostasis in models of obesity

Specialization of Integral Closure of Ideals by General Elements

In this paper, we prove a result similar to results of Itoh and Hong-Ulrich, proving that integral closure of an ideal is compatible with specialization by a general element of that ideal for ideals of height at least two in a large class of rings. Moreover, we show integral closure of sufficiently large powers of the ideal is compatible with specialization by a general element of the original ideal. In a polynomial ring over an infinite field, we give a class of squarefree monomial ideals for which the integral closure is compatible with specialization by a general linear form