Medicine and Health Sciences Commons^™

Impact Of Dietary Modification On Aflatoxicosis In Poultry, Xi Chen

Open Access Dissertations

Aflatoxin contamination in feed and feed ingredients is of high worldwide prevalence, posing serious risks to the livestock industry. A series of studies were conducted to better understand the comprehensive impact of aflatoxicosis and its interrelationships with dietary modifications in broiler chicks and ducks. Results of these studies emphasize the many factors that the severity of aflatoxicosis depends on, including animal species, age, presence of mycotoxin adsorbent, and concentration of major dietary nutrients. Exposure to 2 mg/kg cultured AFB1 led to reduced feed intake, BW gain, depressed feed efficiency, increased relative liver weight, negatively affected serum measures and complement activity, …

Nanoparticle Toxicity And Molecular Mechanisms In Fish: A Case Study With Silver Nanoparticles, Jiejun Gao

Open Access Dissertations

Nanoparticles (NPs) are widely used in a myriad of commercial and industrial products making their entry to the environment a likely event. NPs have unique physical-chemical properties that result from their small size and high surface area to volume ratio, making them highly reactive and potentially toxic. In Chapter 1, we summarize the effects and mechanisms of metal-based NPs on the vascular system. In vitro studies have shown that NPs are anti-angiogenic because they cause inflammation, oxidative stress, and apoptosis of endothelial cells resulting in increased permeability and decreased proliferation and migration. Whole animal studies examining the effects of NPs …

Gonadal Intersex In Teleosts: Mechanisms, Molecular Biomarkers And Diagnostic Assays, Ahmed M.E. Abdel-Moneim Mohamed

Open Access Dissertations

Natural and synthetic estrogenic and androgenic compounds are continuously released into aquatic ecosystems. Exposure of teleost fishes to these contaminants can negatively impact sex differentiation and reproductive output. Specifically, development of gonadal intersex in gonochoristic (fixed sex) fish species has been studied extensively in relation to exposure to this class of compounds. The main objectives of this dissertation were to: 1) conduct field and laboratory studies to investigate the molecular signaling pathways behind the development of gonadal intersex; and 2) establish molecular biomarkers and assays for testing the ability of environmental pollutants to develop this condition using a battery of …

Influence Of Dietary Component Manipulation And Feed Management Strategies On Growth And Rumen Development Of Weaned Dairy Heifers, Tana Shea Dennis

Open Access Dissertations

Well-developed replacement heifers provide a central foundation for the continued success of the dairy industry. Emphasis on improving pre-weaned calf nutrition has predominated in the industry, but opportunities exist to improve post-weaning heifer nutrition and management. We aimed to evaluate common feed management strategies seen in the industry and their effects on growth, feed efficiency (G:F), and rumen development of calves from birth to 8 mo of age using pen- and individually-fed animal trials. Little information exists regarding post-weaning performance and rumen development of calves fed conventional or high planes of nutrition pre-weaning; therefore, we evaluated two milk replacer feeding …

Immune Modulating Functions By Soypeptide Lunasin In Cancer Immunotherapy, Chun-Yu Tung

Open Access Dissertations

Chemotherapy is currently the mainstay of treatment for most cancer patients. Despite its efficacy in eliminating cancer cells, a high percentage of chemotherapy patients eventually relapse or suffer progression of the disease. Immunosurveillance is capable of recognizing and eliminating continuously arising transformed mutant cells, and thus cancer immunotherapy is one of the emerging therapeutic strategies that harnesses the power of the immune system to eradicate chemotherapy-resistant cancerous cells. However, the adverse side effects of chemotherapy impede the therapeutic effects of immunotherapy. Our previous studies demonstrate that lymphoma patients are refractory to clinical immunotherapy because of chemotherapy-induced immune dysfunction. In addition, …

Evaluation Of Negative Energy And Mineral Balance In Periparturient Holstein-Friesian Cattle, Ameer Ahmed Abdelhameed

Open Access Dissertations

Most cows experience a state of negative energy and mineral balance during the periparturient period. This imbalance is a major problem in the dairy industry and it is more frequently seen in multiparous cattle due to their high milk production. A large amount of fat and protein is mobilized in order to address the energy deficit during the periparturient period. The ability to accurately monitor energetics and electrolytes status using accurate, rapid, and low cost point-of-care instruments will assist in optimizing animal health and productivity.

This dissertation contains three studies that evaluated point-of-care instruments for measuring blood and plasma glucose, …

Investigating The Role Of The Basic Helix-Loop-Helix Transcription Factor Mist1 In Pancreatic Diseases, Anju Karki

Open Access Dissertations

Acinar cells of the exocrine pancreas are dedicated to synthesize, package and secrete immense quantities of pro-digestive enzymes to maintain proper metabolic homeostasis for the organism. Dysregulation of enzyme secretion in acinar cells can give rise to exocrine diseases including acute pancreatitis (AP), a disease that targets acinar cells, leading to acinar-ductal metaplasia (ADM), inflammation and fibrosis—events that can transition into the earliest stages of pancreatic ductal adenocarcinoma (PDAC). The focus of this thesis is to interrogate transcriptional regulatory networks that are susceptible to AP and the role that these networks play in acinar cell and exocrine pancreas responses. The …

Influence Of The 3d Microenvironment On Glioblastoma Migration And Drug Response, Ruth Marisol Herrera Perez

Open Access Dissertations

Glioblastoma (GBM) is a highly invasive brain cancer characterized by poor prognosis. Despite significant efforts by the basic and clinical research community our understanding of GBM progression and recurrence has been incremental. Improvements in therapeutic response have been dismal, and GBM continues to be the deadliest tumor of the central nervous system, with patient average survival rate of 12 months. Synergistic relationships that the tumor cells establish with the brain microenvironment have been proven fundamental for successful tumor progression and maintenance. Yet, many in vitro GBM studies are performed in formats that fail to recapitulate the most essential component of …

The Pathological Role Of Acrolein In Experimental Autoimmune Encephalomyelitis And Multiple Sclerosis, Melissa A. Tully

Open Access Dissertations

Multiple sclerosis (MS) is an autoimmune demyelinating neuropathy that affects nearly 2.5 million people worldwide. Despite substantial efforts, few treatments are currently available largely due to limited knowledge of pathogenic mechanisms underlying the disease. The immune-inflammatory nature of the pathology has prompted investigation of the role of oxidative stress in disease development and progression; however targeting reactive oxygen species for neutralization has had marginal success therapeutically, suggesting that an alternate oxidative stress-related target would prove beneficial. Recently, our lab has implicated acrolein, a highly reactive aldehyde that is both a byproduct and catalyst of lipid peroxidation, as a potential therapeutic …

A Novel In Vivo Tumor Oxygen Profiling Assay: Combining Functional And Molecular Imaging With Multivariate Mathematical Modeling, Chung-Wein Lee

Open Access Dissertations

Purpose: The objective of this study is to develop and test a novel high spatio-temporal in vivo assay to quantify tumor oxygenation and hypoxia. The assay implements a biophysical model of oxygen transport to fuse parameters acquired from in vivo functional and molecular imaging modalities. ^ Introduction: Tumor hypoxia plays an important role in carcinogenesis. It triggers pathological angiogenesis to supply more oxygen to the tumor cells and promotes cancer cell metastasis. Preclinical and clinical evidence show that anti-angiogenic treatment is capable of normalizing the tumor vasculature both structurally and functionally. The resulting normalized vasculature provides a more efficient and …

Beta-Lactam Antimicrobial Dosing Optimization In Obese Patients Compared To Non-Obese Patients Using Population Pharmacokinetic/Pharmacodynamic Approach, Eun Kyoung Chung

Open Access Dissertations

Obesity is a significant global health problem and has been associated with altered pharmacokinetics and pharmacodynamics of many drugs. However, little is known regarding the effect of obesity on the pharmacokinetics and pharmacodynamics of many broad-spectrum, beta-lactam antibiotics such as piperacillin/tazobactam, meropenem, and cefepime. The objective of this study is to evaluate the population pharmacokinetics and pharmacodynamics of piperacillin/tazobactam, meropenem, and cefepime in hospitalized obese patients in order to determine dosing regimens that provide similar exposures between obese and non-obese patients. ^ For piperacillin/tazobactam, a retrospective analysis was conducted using prospectively collected serum concentration-time data from two previous studies (Study …

Mach: A Model For Explaining Molecular And Cellular Mechanisms, Caleb M. Trujillo

Open Access Dissertations

Biologists use mechanistic explanations to understand behaviors of the immense complexity of molecular and cellular systems. In undergraduate biology courses, students are expected to explain molecular and cellular mechanisms, but teaching this skill presents many challenges due to the highly abstract, intangible nature of the cellular world, the influence of everyday language, and the tendency of students to overestimate how much they can explain. Therefore, across three studies this dissertation addresses these obstacles to teach undergraduate biology students to explain molecular and cellular mechanisms. ^ The first step was to model how biology experts explain molecular and cellular mechanisms, and …

Show Horse Welfare, Melissa A. Voigt

Open Access Dissertations

In recent years there has been an increase in the public's attention to situations where trainers, owners, and handlers have compromised the well-being of show horses for the sake of winning. These situations may be due to training negligence or naivety of individuals working with the horse. Either way, due to these incidents, increasing pressure has been placed on the horse industry to address show horse welfare. The purpose of this research was to expound on the welfare of stock-type show horses through the perspective of those directly involved; considering the understanding of welfare, the value placed on welfare, and …

Host Cell Death In Legionella Pneumophila Pathogenesis And Immunity, Wenhan Zhu

Open Access Dissertations

Legionella pneumophila is an intracellular pathogen that causes a severe, atypical pneumonia termed Legionnaires' disease. Upon entering the host cell, L. pneumophila resides in a membrane-bound vacuole, in which the bacterium evades lysosomal fusion and replicates. The establishment of the vacuole requires the Dot/Icm (Defect in organelle trafficking/ intracellular multiplication) transport system, which translocates a large number of substrates into host cells to re-orchestrate various cellular processes, such as intracellular trafficking, protein synthesis and host cell death pathways. Therefore, a key step in understanding the biology of Legionella is to dissect the mechanisms of action of the Dot/Icm substrates. By …

Quantitative Modeling Of Spatiotemporal Systems: Simulation Of Biological Systems And Analysis Of Error Metric Effects On Model Fitting, James Hengenius

Open Access Dissertations

Understanding the biophysical processes underlying biological and biotechnological processes is a prerequisite for therapeutic treatments and technological innovation. With the exponential growth of computational processing speed, experimental findings in these fields have been complemented by dynamic simulations of developmental signaling and genetic interactions. Models provide means to evaluate "emergent" properties of systems sometimes inaccessible by reductionist approaches, making them test beds for biological inference and technological refinement.^ The complexity and interconnectedness of biological processes pose special challenges to modelers; biological models typically possess a large number of unknown parameters relative to their counterparts in other physical sciences. Estimating these parameter …

African Starchy Foods, Gastric Emptying, And Starch Digestion In Malian Stunted Children, Fatimata Cisse

Open Access Dissertations

Starch serves as the main energy source in cereal and tuber-rich diets, and its glycemic response profile has been associated with health-related conditions. Sorghum and millet are known to have relatively low starch digestibility, a potentially desirable property for controlling blood glucose response and providing sustained energy. Gastric emptying rates of traditional sorghum and millet-based African foods of the Sahelian region (couscous, thick and thin porridges made from millet and/or sorghum) were compared to those of non-traditional "modern" foods that are mostly consumed in urban areas using a non-invasive 13C-labelled octanoic acid breath test in healthy volunteers. The obtained results …

Prediction Of Parturition And Dystocia In Holstein-Friesian Cattle, And Cesarean Section In Dystocic Beef Cattle, Wen Han Mark Hiew

Open Access Dissertations

Dystocia is a major problem in the dairy industry as it causes livestock and economic loss. It is more frequently seen in primiparous cattle compared to their multiparous counterparts due to their smaller stature and the slow maturation of pelvic dimensions. In some instances, human intervention of the parturition process is imperative to avoid pain, injury, and mortality of the neonate and the dam. The ability to accurately predict dystocia and the time of parturition will ensure that timely assistance can be given to animals that are of high risk of dystocia.^ The present thesis contains four studies that explore …

Dj-1 And Atp13a2: Two Proteins Involved In Parkinson’S Disease, Josephat M Asiago

Open Access Dissertations

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease, affecting approximately 0.3% of the total U.S. population, and its prevalence increases with age. Two neuropathological hallmarks of PD are the loss of dopaminergic neurons in the substantia nigra pars compacta, a region in the midbrain involved in initiating and sustaining movement, and the presence of cytosolic inclusions called Lewy bodies (LBs) in various brain regions. LBs are enriched with fibrillar forms of the presynaptic protein &agr;-synuclein (aSyn). Two autosomal recessive genes implicated in familial PD are PARK9, encoding the P-type ATPase ATP13A2, a lysosomal ATPase; and …

Effects Of Hearing Aid Amplification On Robust Neural Coding Of Speech, Jonathan Daniel Boley

Open Access Dissertations

Hearing aids are able to restore some hearing abilities for people with auditory impairments, but background noise remains a significant problem. Unfortunately, we know very little about how speech is encoded in the auditory system, particularly in impaired systems with prosthetic amplifiers. There is growing evidence that relative timing in the neural signals (known as spatiotemporal coding) is important for speech perception, but there is little research that relates spatiotemporal coding and hearing aid amplification.

This research uses a combination of computational modeling and physiological experiments to characterize how hearing aids affect vowel coding in noise at the level of …