Now showing items 1-20 of 1507

    • A Descriptive Phenomenology of Workplace Incivility Among Operating Room Nurses During the COVID-19 Pandemic

      Martin, Louisa Dasher; Nursing (Augusta University, 2022-07-13)
      Workplace incivility (WPI) and other forms of workplace mistreatment in healthcare are associated with medical errors, increased costs, preventable adverse events, and issues with retention of qualified clinicians. The operating room (OR) can be an exceptionally toxic environment for nurses, and as many as 97% of OR clinicians are exposed to WPI and other disruptive behaviors. Additionally, there is evidence that incivility among registered nurses has increased since the beginning of the COVID-19 pandemic. Major professional and healthcare organizations are calling on healthcare institutions to address the problem. Despite quantitative evidence on the existence and consequences of WPI in the OR, the problem has continued to persist, and there are critical gaps in the literature. There is minimal qualitative research on the topic, and there are no current data on the efficacy of interventions for addressing WPI in the OR. Of utmost importance is the need to understand how the COVID-19 pandemic has influenced WPI among OR nurses. Thus, there is a need for a qualitative study exploring WPI among this population during the COVID-19 pandemic. The purpose of the study was to describe the essential structure of the lived experience of WPI among registered nurses practicing in the circulator role in ORs within hospitals in the southeastern United States during the COVID-19 pandemic. I conducted the study utilizing Colaizzi’s descriptive phenomenological methods. A total of 15 OR nurses from five different sites participated, and each participating nurse completed up to two semi-structured interviews. Based on data analysis, three themes were revealed: (a) Enduring incivility as an individualized test of one’s mettle, (b) COVID-19 as an accelerant for WPI, and (c) Addressing WPI through accountability, communication, and education. While participants experienced WPI in a variety of ways, certain similarities were threaded throughout their descriptions of the phenomenon. The experience was primarily described as unpleasant and complex, especially for those who were the target of WPI. Additionally, the experience was influenced by a number of factors, some of which were unique to each individual and some which were unique to the OR itself. COVID-19 seems to have exacerbated the problem of WPI in the OR, creating an environment characterized by greater stress, tension, and frustration. There is an urgent need to address WPI in the OR, especially through accountability, communication, and education. OR managers and leaders can use the findings of this study to enhance the overall health of the environment and begin to foster a culture of civility. Specifically, managers can use the findings to improve the experience of being new in the OR, as well as the experience of reporting WPI in the OR. There is a need for additional knowledge development related to new graduate nurses in the OR, as well as the impact of sociodemographic factors on WPI in the OR. In addition, there is a need for research on targeted interventions for addressing WPI in the OR.
    • The Roles of Circadian Disruption and Reactive Oxygen Species Overproduction in the Development of Obesity-Associated Cardiovascular Disease

      Padgett, Caleb; Biomedical Sciences (Augusta University, 2022-07-13)
      Obesity is a complex and multifactorial disease that is endemic in the United States, affecting over 40% of the US population and contributing to over $150 billion in medical cost. Obesity and metabolic disease are major risk factors for cardiovascular disease, which is the leading cause of death among Americans, especially those in the southeast. While the detrimental effects of obesity on cardiovascular health are well-documented, the mechanisms linking aberrant metabolism to vascular dysfunction are poorly understood. In the present study, we investigate the role of the vascular endothelium in mediating the progression of cardiometabolic disease through disruption of the peripheral circadian clock as well as through overproduction of reactive oxygen species, both of which are implicated in the development of endothelial dysfunction and the downstream acute cardiovascular diseases it predicts. We demonstrate that obesity causes a unique circadian disruption in the endothelium that is not recapitulated by other established models of circadian disruption, and that rhythmic expression of the essential vasodilatory enzyme endothelial nitric oxide synthase (eNOS) is disturbed. Expression of NADPH oxidase I (NOX1), the major pathological reactive oxygen species (ROS)-producing enzyme in the vasculature, was markedly increased in the endothelium, and was found to be even more highly expressed in the obese microvascular endothelium. Further, endothelial expression of the receptor for glycation end-products galectin-3 (GAL3) was found to correlate with NOX1 expression levels, leading us to hypothesize that GAL3 contributes to obesity-induced NOX1 overexpression in the microvascular endothelium. We demonstrate that deletion of GAL3 resolves obesity-induced endothelial dysfunction and hypertension by decreasing NOX1 expression and subsequent ROS overproduction. Finally, we demonstrate that the GAL3/NOX1 axis is amenable to beneficial changes in glucose handling by treatment with metformin, augmentation of skeletal muscle mass, or improvement of insulin signaling. Taken together, these data indicate that GAL3 is an attractive therapeutic target to ameliorate obesity-induced cardiovascular disease.
    • Enhancing Immune Therapy by Modulating Cell Death

      Merting, Alyssa; Biomedical Sciences (Augusta University, 2022-07-13)
      Colorectal cancer is the second leading cause of cancer mortality in the United States. Treatments for colorectal cancer become limited as the cancer progresses. The most effective treatment is surgery, which is most effective while the tumor is in the early stages. Treatments used for advanced colorectal cancer includes chemoradiation and in some cases immune checkpoint blockade (ICB) immunotherapies, however, only a small percentage of colorectal cancers respond to ICB therapies. One way to potentially increase ICB efficacy may be to target myeloid-derived suppressor cells (MDSCs). MDSC accumulation is a known hallmark of cancer, with their key function being immune suppression via multiple mechanisms. In this study it is reported that MDSC accumulation is regulated by TNF-RIP1-mediated necroptosis. It was determined that inhibition of DNA methyl transferases (DNMTs) with Decitabine (DAC) abolished MDSC accumulation and increased activation of antigen-specific cytotoxic T lymphocytes (CTLs) in tumor-bearing mice. Furthermore, recombinant TNF induced MDSC cell death in a dose and RIP1-dependent manner. These data show that autocrine IL6 activates the STAT3-DNMT axis to epigenetically silence the TNF-RIP1 necroptosis pathway to sustain MDSC survival and accumulation in cancer. Targeting the TNF-RIP1 necroptosis is potentially an effective approach to suppress MDSCs and activate tumor reactive CTLs in the tumor microenvironment. Another hallmark of colorectal cancer is the loss of FAS expression, the death receptor for FASL on CTLs. However, it is unknown whether restoring FAS expression alone is sufficient to suppress colorectal cancer development. Codon usage optimized mouse and human FAS cDNAs were designed, synthesized, and cloned into a plasmid. The plasmid was then encapsulated within cationic lipids to formulate nanoparticle DOTAP-Chol-Fas. Overexpression of codon usage-optimized FAS in metastatic mouse colon-tumor cells enabled FASL induced elimination of FAS+ tumor cells in vitro, suppressed colon tumor growth, and increased the median survival rate of tumor-bearing mice in vivo. Overexpression of codon-optimized FAS-induced FAS receptor auto-oligomerization and tumor cell auto-apoptosis in metastatic human colon tumor cells. DOTAP-Chol-hFAS therapy is also sufficient to suppress metastatic human colon tumor xenograft growth in athymic mice, stopping PDX tumor growth in vivo. Thus this study determined that delivery of FAS DNA nanoparticles is sufficient to suppress human colon tumor growth in vivo.

      Parker, Emily; Biomedical Sciences (Augusta University, 2022-07-13)
      Loss of skeletal muscle is associated with an increased risk of falls, fractures, and mortality. Muscle atrophy can occur in settings such as prolonged bed rest, spinal cord injury, aging and spaceflight, and is often accompanied by bone loss; however, the cellular and molecular mechanisms underlying muscle and bone atrophy remain poorly understood. Fibro-adipogenic progenitor cells (FAPs) play a significant role in maintaining skeletal muscle mass through their complex secretome, but their role in disuse atrophy has not been explored. This study tests the hypothesis that muscle disuse alters the FAP secretome, contributing to muscle atrophy and bone loss. Results show that FAPs isolated from immobilized muscle have increased expression of IL-1β and Cdkn2a (p16INK4A), factors that can induce muscle cell atrophy and senescence, respectively. On the other hand, IL-1β depletion in IL-1β deficient knockout mice attenuates muscle atrophy with immobilization. Moreover, mice lacking IL-1β do not lose bone strength with immobilization and do not increase bone resorption. Hindlimb immobilization was also found to significantly alter the microRNA cargo of FAP-derived extracellular vesicles (EVs), but changes in these miRNAs were not observed in EVs from IL-1β deficient mice. Overall, our data suggest that FAP-derived IL-1β plays an important role in the muscle atrophy and bone loss that occur with disuse, and thus may represent a potential therapeutic target for improving muscle and bone function in settings of unloading.
    • The Influence of Depression on Bariatric Surgical Outcomes

      Puig-Baker, Tracey S.; Nursing (Augusta University, 2022-07-13)
      Over 40% of adults in the United States are classified as obese. American adults with severe obesity experience symptoms of depression at double the rate of normal-weight people. Bariatric surgery (BS) is a safe and effective treatment for severe obesity that results in long-term weight loss. The estimated 19% of BS patients who suffer from depression after surgery exhibit a lower-than-average percentage of excess weight loss (%EWL) over time. These BS patients also do not attend follow-up appointments, which makes treating their symptoms of depression difficult for healthcare providers. This study examined the relationship between depression, %EWL, and follow-up attendance to ascertain if depression influenced whether BS patients achieved their %EWL goal as well as attended their 12- and 24-month follow-up appointments. Non-identifiable data in 212 electronic medical records were examined of adults aged 18-64 who had their first BS from 2012 to 2020 at an academic medical center. The BS patients were sorted into two depression status groups per their pre-surgical BDI-II score for statistical analysis. This categorization resulted in 44% of the BS patients in the with depression group (mean BDI-II score 21 ± 9 points) and 56% in the without depression group (mean BDI-II score 8 ± 5 points). A repeated measures mixed model found no statistically significant decrease in %EWL between or within the depression status groups at 12- and 24-months post-BS – even when controlling for patient characteristics (age, sex, race, insurance type, marital status, education level, employment status, and antidepressant medication). A generalized linear mixed model found a statistically significant decrease in the follow-up attendance from 12 to 24 months within both depression status groups (with depression p < .001; without depression p = .003) when controlling for the same patient characteristics except race. However, when controlling for patient characteristics, no statistically significant decrease in follow-up attendance was found between the depression status groups at 12 months (p = .887) or 24 months (p = .229). The results of this study were inconclusive regarding whether depression influenced BS outcomes since BS patients were only assessed for symptoms of depression before surgery and not at each follow-up appointment after surgery. A prospective study with a mixed-methods design is needed to determine if surgical outcomes are associated with depression and why BS patients do not attend follow-up appointments. Follow-up attendance is essential for treating BS patients over time, so they can successfully achieve and maintain their weight loss goals.  

      Breithaupt, Rebekah; Department of Psychological Sciences (Augusta University, 2022-05)
      Adverse childhood experiences (ACEs) are a significant and highly prevalent issue. ACEs include physical, psychological, and sexual abuse, dysfunction in the home, parental loss through divorce and or death, and other potentially traumatic events (Felitti et al., 1998). More research is needed to gain a better understanding of how ACEs are linked to long-term negative mental health outcomes and physiology. A non-invasive way to understand the relationship between adversity and mental and physical health is to examine physiological activity patterns of the autonomic nervous system (sympathetic and parasympathetic). Such physiological measures include electrodermal activity (EDA), heart rate (HR), and heart rate variability (HRV). The purpose of this study was to investigate if certain autonomic activity patterns are associated with ACEs and if these activity patterns can be observed in early adulthood. To do this, EDA, HR, and HRV were collected from participants during a baseline period of rest and while they completed a stressful task (Stroop Test). Additionally, participants were measured in this study using the Adversity and Abuse Items from the Harvard Second Generation Study Questionnaire (Morrill et al., 2019). Certain demographic information is also being collected. The hypotheses of this study were as follows: 1) Individuals who score high on the ACEs scale will display higher levels of HR and EDA at baseline than those with low scores, 2) individuals who score high on the ACEs scale will have higher HR and EDA during the stress task than those with low ACEs scores, and 3) Participants in the high ACEs group will have lower overall HRV than those in the low ACEs groups. The results of this study did not show any significant differences between ACEs groups and their physiological measures during baseline or during the Stroop task.

      Garner, Jamani; Department of Psychological Sciences (Augusta University, 2022-05)
      A key goal in preclinical pain research is improving the translational value of findings by modeling pain states elicited in humans. Examining the expression and treatment of pain-related disruption of behavior represents one approach to improving the alignment between preclinical pain research and clinical settings. Past studies support the ability of the intermediate efficacy opioid, morphine, to restore pain-related depression of nesting in mice. In the present study, we aimed to investigate the effects of the low efficacy opioid, buprenorphine, and the high efficacy opioid, methadone, on lactic-acid induced depression of Nestlet shredding in male and female ICR mice. At the start of test sessions, 5 × 5 cm Nestlets were weighed and suspended from the wire lid of the home cages. Under control conditions, mice removed pieces of the suspended Nestlets to build nests. The results indicated that intraperitoneal injections of 0.18% lactic acid disrupted Nestlet shredding. Unlike morphine, both buprenorphine and methadone failed to restore acid-induced depression of shredding. In the absence of acid, both buprenorphine and methadone significantly depressed shredding. Our findings highlight the need for additional testing of these drugs across different pain procedures and noxious stimulus intensities to determine whether a balance can be achieved between their rate-decreasing and antinociceptive effects.

      Moss, Tierra; Department of Psychological Sciences (Augusta University, 2022-05)
      Romantic relationships offer a space for companionship, belonging, love, and intimacy. However, relationships do not exist in a vacuum. One important external factor that can affect the functioning of a relationship is experiences of racism. Yet, few studies have examined the effects of racism on relationship functioning. Data from 122 participants currently in romantic relationships in which one partner is a person of color was used to examine the association between experiences of racism and negative and positive aspects of relationship functioning as well as perceived partner alternatives. Experiences of racism were positively associated with anger, perceived partner anger, and withdrawal; and negatively associated with perceived partner support. Experiences of racism were also positively associated with perceptions of comparison level for alternatives. Findings suggest that experiencing racism is related to both negative and positive aspects of relationship functioning as well as perceived partner alternatives. Future research should seek to further examine these relationships.

      Jarrard, Christy; Department of Psychological Sciences (Augusta University, 2022-02)
      The quality of the therapeutic alliance and the depth of the therapeutic work are thought to be two of the most important contributors to client outcomes. Moreover, it is clear that therapists differ in their ability to form strong working relationships and engage meaningfully with clients. Much less is known with regard to which specific therapist characteristics and techniques are most helpful in forming strong bonds with clients and deepening the work, especially within trainee populations. This study utilizes a multi-trait multi-method assessment of clinical graduate trainees (N = 65) prior to training and then matches these scores to process measures collected from their first therapy case. The therapy was video recorded, and observer ratings of exploration, insight, action, and supportive techniques were provided for the third session. Clients also completed the Working Alliance Inventory and the Session Evaluation Questionnaire at the third session. Regression results indicate that therapist characteristics (age, GRE score, interpersonal problems, perspective taking, and emotional investment in relationships) and technique usage (exploration, insight, action, and support) significantly predicted client-rated depth. While the overall two-step regression model was not significant for alliance, there was a significant correlation with a moderate effect for observer-rated usage of support and client-rated alliance scores. Exploratory regression results indicated technique usage variables independently predict client alliance ratings with support having a positive impact. Implications of the findings as they pertain to selection and training in clinical and counseling training programs are discussed.
    • The Inhibition of NADPH Oxidase 1/Protein Disulfide-Isomerase Increases BIM in Pancreatic Cancer

      Knox, Henry John Douglas; Biomedical Sciences (Augusta University, 2022-05)
      Pancreatic cancer requires elevated protein synthesis. To maintain endoplasmic reticulum (ER) homeostasis, chaperones are overexpressed. Persistent ER stress activates the unfolded protein response (UPR), which can become overwhelmed and lead to cell death. Reactive oxygen species (ROS) from NADPH oxidases (Noxs) can regulate ER homeostasis. In particular, the chaperone protein disulfide-isomerase (PDI) colocalizes with Nox1 in the ER to regulate its activity. Because Nox1 is expressed in the stroma of pancreatic cancer, I studied the extent to which Nox1-derived ROS help establish an adaptive ER homeostasis via PDI in pancreatic cancer cells. I generated a pancreatic cancer mouse model lacking the Nox1 gene in the whole body (Nox1-null KPC mice). Nox1-competent KPC mice were used as a control. The induction of Cre recombination was done by administration of tamoxifen for five consecutive days. After 2 months of tamoxifen induction, the pancreas was harvested. Western blotting was carried out to evaluate PDI, UPR activation, ER stress and cell death. The Nox1-null KPC mice were viable. The lack of Nox1 reduced PDI, C/EBP homologous protein (CHOP) in KPC mice. The UPR sensor IRE1α and the growth arrest and DNA damage-inducible 34 (GADD34) were absent in Nox1-competent KPC mice, but they were recovered in Nox1- null KPC mice. In Nox1-null KPC mice, the apoptotic protein BIM was increased. I concluded that in pancreatic cancer, the lack of Nox1 decreased PDI, which led to an accumulation of unfolded proteins and activation of UPR system. GADD34 recovery increased protein synthesis, worsening the scenario. Persistent ER stress overwhelmed the UPR system, which caused BIM-induced cell death.
    • Identification and Characterization of Force Sensitive Domains using an In Vivo Dorosphila Synthetic Biology Platform

      Harman, Jacob Henry; Biomedical Sciences
      The Notch protein is a family of highly conserved transmembrane signaling proteins that are found in all metazoan life. This protein family plays many roles in developmental and regulatory pathways in these organisms such as the development of the human vertebral column and the Drosophila adult wings. The Drosophila Notch protein has been the focus of recent research as this protein has shown to be dependent on a unique signaling mechanism that relies on the force being applied to the receptor by the endocytosis of a bound ligand for a cleavage event to occur. This protein has been shown to only signal in the presence of this endocytosis force which allows for cleavage at the S2 and S3 sites on the protein which allows for a transcription factor to be released from the membrane and enter the nucleus. In synthetic biology, this protein has found a role in creating customizable cell-cell signaling platforms known as Synthetic Notch or Syn-Notch. As demonstrated in previous research, Notch proteins contain highly modifiable ligand binding and transcription factor domains that can be interchanged with other ligand binding and transcription factor domains from non-Notch proteins without affecting the protein signaling. In addition to the ligand-binding and transcription factor, the Notch protein contains a Negative Regulatory Region (NRR) which functions as a force sensor domain and allows for the force signaling activation seen in the native Notch proteins. This region of the Notch protein is often conserved in Syn-Notch systems as a means of controlling the signaling of Syn-Notch proteins used in precision medicine. The unique force-sensing function of this domain has raised questions regarding the characteristics of this domain that allow for it to act in a force-sensing manner and if this domain is as interchangeable as its other components. In this study, domains from other non-Drosophila Notch proteins and non-Notch protein domains were evaluated in an in vivo Drosophila platform for the ability to function as a force sensor domain. In this screen, several unique force sensor domains were identified as having the ability to recapitulate the force sensing characteristic of the canonical Notch NRR. While a common thread between these domains in terms of defining characteristics remains elusive, this study was able to demonstrate the feasibility of this screening method to identify force-sensitive domains and identify 4 domains that exhibit this characteristic. The identification of these domains which are force sensitive not only allows for the characteristics to function as force-sensitive domains but also provides alternative force sensors with differing force sensitivities when compared to the canonical Notch NRR for use in Syn-Notch systems. The development of these receptors will not only contribute to the field of synthetic biology as means to create synthetic platforms for use in future research, but these receptors will allow for the development of even more precise treatments using these synthetic receptor systems in clinical therapies.
    • Prevalence of Chronic Medical Conditions Among the 1990-1991 Gulf War Female Veterans

      Ansa, Benjamin E; Public Health (Augusta University, 2022-05)
      Background: The care of the large number of women joining the U.S. military is receiving increased attention. Currently, 56% of all women veterans alive served during the 1990–1991 Gulf War (GW). Veterans of the GW have reported poorer health outcomes than their counterparts who did not deploy because of the potential health risks associated with military service during the GW, and the possible use of chemical and biologic warfare agents. Military service and deployment affect women differently than men, however gaps exist in the research of common chronic conditions among veterans due to the lack of gender-specific results from published studies. Purpose: The specific aims of this study were 1) to examine and compare the prevalence of chronic medical conditions (CMCs) among deployed GW female veterans and GW era female veterans that did not deploy; 2) to examine the prevalence of exposure to environmental toxicants among deployed GW female veterans and compare the prevalence of CMCs between exposed and unexposed females; and 3) to examine and compare the prevalence of CMCs among deployed male and deployed female veterans of the GW. Methods: Data from three longitudinal epidemiologic studies of the health of the 1990-1991 U.S. GW veterans were analyzed for this study. Cross tabs and logistic regression were done to calculate the prevalence and prevalence ratios (PRs) of seventeen self-reported CMCs among the study population. PRs were also used for assessing the relationship between self-reported exposure to environmental toxicants and the prevalence of CMCs among deployed female veterans. Results: The most prevalent CMCs reported by both deployed and non-deployed female veterans were headaches and high blood cholesterol. Compared to non-deployed females, significantly higher proportions of deployed females reported migraine headaches, osteoarthritis, and skin problems. In addition, the prevalence of headaches was almost three times higher for deployed female veterans, compared to deployed male veterans. Anthrax vaccine, oil well fires, pyridostigmine bromide, petroleum combustion products and chemical weapons were the toxicants with the highest proportions of reported exposure among deployed female veterans. Compared to unexposed females, significantly higher proportions of exposed females reported migraine headaches, headaches (other than migraines), high blood cholesterol, hypertension, acid reflux/GERD, irritable bowel syndrome, colon polyps, thyroid disease, osteoarthritis, tinnitus, asthma, chronic lung disease, and skin problems. Conclusions: Compared to their counterparts, higher prevalence of some CMCs were observed among deployed female veterans of the 1990–1991 GW, especially among those that reported toxicant exposures. This information about CMCs and exposures is useful for guiding medical assessments and policy development affecting this group of female veterans.
    • The Perioperative Synergy Index

      Elliott-Dawe, Cheryl Ann; Nursing (Augusta University, 2022-05)
      The presence of synergy within perioperative services has a significant bearing on a hospital’s viability and positive patient outcomes. Synergy is a positive emergence that arises as a value-added return on investment when all contributing factors and personnel work toward common goals. The purposes of this research were to develop a perioperative synergy model and to create an index to evaluate perioperative synergy. Research questions were: (a) What are the antecedents of synergy in the context of perioperative services? (b) What research is currently being conducted on high functioning perioperative services across perioperative disciplines? (c) What are the items necessary to ensure face and content validity of a perioperative synergy index? (d) How should the items be worded to ensure clarity, readability, and usability of a perioperative synergy index? (e) What are the underlying constructs that constitute perioperative services synergy? and (f) What are the psychometric properties of the perioperative synergy index? A three-phase survey methodology was adopted. For Phase 1, a directed content analysis of 20 years of research literature on high performing ORs was conducted using nine domains of a theoretical perioperative model. The analysis yielded 221 items that were presented to a panel of perioperative experts who rated each item’s relevance to perioperative success on a 4-point scale. Expert agreement on content was evaluated using a content validity index. In Phase 2, experts judged the wording and clarity of each item and of the instructions. Inter-rater agreement on clarity of items and instructions was evaluated using Gwet’s AC1 coefficient. For Phase 3, perioperative managers across the nation were surveyed and asked to rate levels of agreement with the items on a 6-point Likert scale as each item pertained to their hospital. Confirmatory factor analyses were completed on the responses, resulting in a model consisting of nine constructs and 53 indicators. Construct, convergent, and discriminant validity were assessed. Reliability was evaluated using composite reliability, inter-item correlations, and average inter-item correlations. Factor scores were employed to calculate a perioperative synergy index coefficient that ranged from 0 to 1, with higher values indicative of higher functioning perioperative services at the hospitals involved in the study. Managers can use the index to identify areas in need of improvement and can use the model to guide process improvements. Following further refinement, the index may serve as a new way to evaluate performance and standardize protocols across healthcare systems.
    • Twist1 Evokes Matrix Metalloproteinase 9 and Collagen IV Synthesis in Activated Pancreatic Stellate Cells

      Geister, Emma; Biomedical Sciences (Augusta University, 2022-05)
      Background: Pancreatic cells are embedded in an extracellular matrix (ECM) and are also surrounded by a thin sheet of specialized extracellular matrix known as basal lamina. In healthy pancreas, pancreatic stellate cells (PaSCs) are responsible for the synthesis of basal lamina, which is mainly composed of collagen IV and laminin. In chronic pancreatitis (CP), PaSCs are responsible for the synthesis of fibrotic tissue, which is mainly composed of fibronectin and collagen I. Reactive oxygen species (ROS), which are predominant inflammatory mediators in CP, evoke the formation of fibrotic tissue by PaSCs. One of the sources of ROS is NADPH oxidase (Nox) enzymes. In particular, Nox1 has been associated with both fibrogenesis in a CP mouse model and an up-regulation of the transcription factor Twist1 and matrix metalloproteinase (MMP) 9 in CP-activated PaSCs. I sought to determine the functional relationship between Twist1 and MMP-9, as well as other PaSC-produced proteins. Therefore, my aim was to assess the extent to which Twist1 up-regulates MMP-9 and other PaSC-produced proteins. Methods: To overexpress Twist1, I infected activated PaSCs from Nox1-null mice with retroviruses expressing either mouse Twist1 or the empty backbone. I compared the relative expression of MMP-9 and other PaSC-produced proteins using quantitative PCR. To examine whether MMP-9 expression is regulated by Twist1 at the transcriptional level, I carried out a dual-luciferase reporter assay using a pGL2 Luciferase Reporter Vector carrying the human MMP-9 (pGL2-hMMP-9) promoter. I co-transfected HEK293 cells with human Twist1 in pCMV6 vector, or the empty backbone (negative control) along with human pGL2-hMMP-9 promoter vector or pGL3-control vector using Lipofectamine 3000. As a positive control, I co-transfected HEK293 cells with human NF-ĸB1 in pFUW-tetO vector along with the pGL2-hMMP-9 promoter. After 48 h, I performed the dual-luciferase reporter gene assay. Results: I found that the up-regulation of Twist1 in culture-activated PaSCs from Nox1-null mice increased MMP-9 mRNA level, but it did not modify the expression of PaSC-produced proteins linked to fibrosis [e.g., collagen I, fibronectin, α-smooth muscle actin, transforming growth factor-β (TGF- β), and interleukin-6 (IL-6)]. Therefore, I studied the expression of collagen IV, a component of basal lamina and found that the expression of Twist1 in activated PaSCs from Nox1-null mice increased collagen IV at the mRNA level. I also found that Twist1 increased the expression of MMP-9 at the transcriptional level in a NF-ĸB dependent manner using a dual-luciferase assay. Conclusion: Twist1 in PaSCs induced the expression of MMP-9 and collagen IV, at the transcriptional level. NF-ĸB was required for the transcriptional up-regulation of MMP-9 by Twist1. The expression of other PaSC-produced proteins, including collagen I, fibronectin, IL-6, α-smooth muscle actin, and TGF-β, were not affected. Since Twist1 in activated PaSCs was responsible for the synthesis and remodeling of the basal lamina in healthy pancreas, I concluded that the overexpression of Twist1 using a retrovirus approach was not sufficient to change the phenotype of PaSC from a basal lamina “maker” to a fibrotic tissue “maker.”
    • T cells and NLRP3 Mediate High Fat Diet-Induced Increases in Blood Pressure and Adiposity in Female and Male Dahl Rats

      Ramirez, Lindsey; Biomedical Sciences (Augusta University, 2022-05)
      Cardiovascular disease (CVD) is the leading cause of death worldwide in both sexes, with hypertension being an important modifiable factor. To increase the number of people with adequate blood pressure control, a better understanding of the mechanisms controlling the development of hypertension is necessary. Chronic consumption of a high fat diet (HFD) increases blood pressure and adiposity. Furthermore, clinical data suggest that women may be predisposed to worse cardiovascular health in instances of excess adiposity. Thus, these experiments were designed to test the central hypothesis that a HFD will increase blood pressure and adiposity more in females vs males. Sprague Dawley rats were resistant to HFD-induced increases in blood pressure or fat mass. Conversely, 10 weeks of HFD treatment increased blood pressure, fat mass, and adipose tissue weight in female and male Dahl Wild Type (WT) rats. This was accompanied by a pro-hypertensive T cell profile in both sexes. This finding pointed to a role for T cells in mediating the morbidity observed, T cell-deficient rats were utilized. T cell knock out (KO) blunted the HFD-induced hypertension in both sexes, but only the HFD-induced increase in adiposity in males. Due to the observed protective role of T cell KO, it was crucial to determine what could be activating T cells. NLRP3 is a pattern recognition receptor which activates T cells and adipogenesis, NLRP3 deficient rats were randomized to a Control (Ctrl) or HFD treatment. NLRP3 KO blunted the HFD-induced adiposity in both sexes. It is well known that free fatty acids (FFAs) can activate NLRP3, so a FFA panel was performed in Dahl WT animals. Females had a more pro-hypertensive FFA profile. The Dahl WT rat is a good model to use to study the loss of protection of females that are on a HFD. Additionally, these data demonstrate that T cells and NLRP3 are playing sex-specific roles to promote the HFD-induced increases in adiposity and blood pressure. Finding sex-specific mechanisms that mediate these morbidities will reduce the number of people that develop hypertension and subsequently, CVD, the number one killer of both men and women in the US.
    • High Dimensional Bayesian Multinomial Logistic Regression

      Dow, James Francisco; Biostatistics (Augusta University, 2022-05)
      Classification is an important area in statistics and machine learning where one is interested in determining class membership based on a set of covariates or predictors, which are possibly high-dimensional. A common application is in genomic studies, where finding genes (predictors) associated with a categorical phenotype such as disease status or tissue type can be useful for prevention or determining prognosis. Regression-based modeling allows for linking these predictors, or combinations of them, probabilistically to the different categories of the phenotype of interest. Multinomial logistic regression is a natural statistical framework that provides a way to model the effects of predictors on the probability of a multi-category outcome variable with two or more classes. We propose a Bayesian hierarchical model that uses multinomial logisitic regression with point mass mixture priors to select best subsets of predictors for classification. We develop a Markov chain Monte-Carlo algorithm based on Gibbs sampling to compute the corresponding posterior distribution for the model. We do so by exploiting the P\'{o}lya-Gamma mixture of normal representation that has been derived in the logistic regression setting. Further, we prove that the proposed hierarchical model is model selection consistent in the strong sense. Finally, we compare the proposed methodology, in terms of model selection and classification, to several popular statistical and machine learning procedures in simulation and on a real data set.
    • Activation of a molecular chaperone (sigma 1 receptor) in a murine model of autosomal dominant retinitis pigmentosa.

      Barwick, Shannon; Biomedical Sciences (Augusta University, 2022-05)
      Retinitis pigmentosa (RP) is a devastating group of inherited retinal diseases that leads to visual impairment and eventually complete blindness. Currently no cure or treatment exists for RP patients, thus research into prolonging the vision in these patients is imperative. Sigma 1 receptor (Sig1R) is a promising small molecule target that appears to have neuroprotective benefits in the retina of fast degenerating mouse models. However, it is not clear whether Sig1R activation can provide similar neuroprotective benefits in more slowly progressing RP models, which are more similar to human patients. In this study, we examined whether Sig1R activation can be neuroprotective (i.e. prolong vision) in a more slowly progressing mouse model of autosomal dominant retinitis pigmentosa, RhoP23H/+. Current studies in the field give a brief overview of the RhoP23H/+ degeneration, but do not give a complete characterization of disease progression. Aim 1 of this study sought to further characterize the degeneration of the RhoP23H/+ mouse using 3 in vivo methods, Optomotor Response (OMR), Electrophysiology (ERG), and Spectral Domain-Optical Coherence Tomography (SD-OCT). A slow retinal degeneration was observed in both male and female RhoP23H/+ mice when compared to WT. Visual acuity showed a gradual decline through 10 months. Interestingly, visual acuity was still detectible, albeit significantly reduced through 10 months in both male and female mutant mice. Females appeared to have significantly lower visual acuity than males. These RhoP23H/+ mice showed a gradual decline in scotopic and photopic responses. Aims 2 and 3 sought to investigate the neuroprotective benefits of Sig1R activation in the RhoP23H/+ mouse model. Mutant mice were treated with a high specificity Sig1R ligand (+)-pentazocine ((+)-PTZ) 3x/week and examined using OMR, ERG, SD-OCT. A significant retention of visual function was observed in both males and females at 10 months of age, with treated females retaining ~50% greater visual acuity than non-treated mutant females. Using ERG, significant retention of scotopic and photopic b-wave amplitudes were observed at 6 months in both male and female mice treated with (+)-PTZ. Further, in vivo analysis of ONL thickness revealed a significant retention in both male and female treated mice. Histological studies using retinal cryosections showed significant retention of IS/OS length (~50%), ONL thickness, and number of rows of PRC nuclei at 6 months in both male and female (+)-PTZ-treated mice. Interestingly, electron microscopy revealed preservation of OS discs in (+)-PTZ treated mutant mice. Taken collectively, the in vivo and in vitro data represent the first report of Sig1R activation rescuing visual function and structure in the RhoP23H/+ mouse model. These results are promising and lay the framework for future studies to investigate Sig1R as a potential therapeutic target in retinal degenerative disease.

      Abdelsaid, Kareem; Biomedical Sciences (Augusta University, 2022-05)
      The overall goal of this dissertation is to elucidate novel mechanisms by which communication of skeletal muscle (SKM) and endothelial cells (ECs) through “exosomes” regulates adaptive angiogenesis and regeneration of SKM in response to physical exercise in type 2 diabetes mellitus (T2DM) (project 1) or injury (project 2) by focusing on the Copper (Cu) transporter ATP7A-extracellular SOD (ecSOD, SOD3) pathway. In project 1, we investigated the role of exercise-induced angiogenic effects on ECs in T2DM. We isolated plasma exosomes from control, T2DM and SOD3-/- mice with two weeks of voluntary wheel exercise using differential ultracentrifugation. Isolated exosomes were characterized by ZetaView, TEM and exosome markers (CD63 and Tsg101). Both SOD3 and ATP7A proteins were significantly induced in plasma exosomes by exercise in both mice and humans. Plasma exosomes from T2DM and SOD3-/-/T2DM sedentary mice impaired ECs angiogenic function compared to control mice, which were restored by exercise in only T2DM but not SOD3-/-/T2DM mice. Furthermore, exosomes overexpressing SOD3 significantly enhanced angiogenesis in ECs by increasing local H2O2 levels in a heparin binding domain-dependent manner and restored wound healing and angiogenesis in T2DM or SOD3-/- mice. In project 2, we investigated the role of Cu transporter ATP7A in myogenic differentiation and skeletal muscle regeneration upon injury. C2C12 myoblasts differentiation to myotubes was associated with an increase in ATP7A and SOD3 expression in cell lysates and exosomes isolated from conditioned media. ATP7A depletion with shRNA in myoblasts significantly inhibited myogenic differentiation and angiogenic effects of conditioned media-derived exosomes. Mechanistically, silencing SOD3, chelating Cu by TTM or inhibiting lysyl oxidase (LOX) activity by BAPN significantly inhibited myogenic differentiation, suggesting that ATP7A-SOD3/LOX axis is required for Cu-dependent myogenesis. Cardiotoxin-induced SKM injury model reveals that ATP7A expression was increased in activated, but not quiescent Pax7-positive satellite cells in injured SKM. Functionally, both Cu transporter defective ATP7A mutant and SOD3-/- mice showed impaired SKM regeneration, diminished myofiber sizes, decreased number of centralized myonuclei and satellite cells. In conclusion, our study reveals a novel role of Cu transporter ATP7A and exosomal SOD3 in promoting adaptive angiogenesis and SKM regeneration serving as a novel promising therapeutic tool for resolving impaired angiogenesis.

      Glover, Michell; Advanced Studies Innovation (Augusta University, 2022-05)
      The roles of school leaders have transformed significantly over time, making necessary shifts to place student learning at the core of what principals do. School leadership preparation has also evolved to keep up with the changing responsibilities and challenges that principals encounter. Although effective school leaders are recognized for their character and exemplary practices that contribute to and build collaborative school communities, principals have multiple responsibilities and often experience challenges while leading their schools. The role of the school leader has changed over the course of history. In response to these role shifts, the standards and practices providing the structure for post-secondary preparation and training programs, state certification, and formal evaluation programs have also had to adjust to keep up with societal changes and responsibilities of school leaders. While principals perform their regular responsibilities, with accompanying challenges, the COVID-19 pandemic has created a myriad of new challenges for school leaders around the globe. Although challenges are not new to the principalship, this study seeks to investigate the challenges K-12 school leaders experienced during the COVID-19 pandemic, how their leadership preparation and training did or did not prepare them to manage these challenges, and investigate the solutions principals implemented to counter the challenges experienced. Keywords: , , , professional development

      Workman, Joseph Barnett; Advanced Studies Innovation
      The roles of school leaders have transformed significantly over time, making necessary shifts to place student learning at the core of what principals do. School leadership preparation has also evolved to keep up with the changing responsibilities and challenges that principals encounter. Although effective school leaders are recognized for their character and exemplary practices that contribute to and build collaborative school communities, principals have multiple responsibilities and often experience challenges while leading their schools. The role of the school leader has changed over the course of history. In response to these role shifts, the standards and practices providing the structure for post-secondary preparation and training programs, state certification, and formal evaluation programs have also had to adjust to keep up with societal changes and responsibilities of school leaders. While principals perform their regular responsibilities, with accompanying challenges, the COVID-19 pandemic has created a myriad of new challenges for school leaders around the globe. Although challenges are not new to the principalship, this study seeks to investigate the challenges K-12 school leaders experienced during the COVID-19 pandemic, how their leadership preparation and training did or did not prepare them to manage these challenges, and investigate the solutions principals implemented to counter the challenges experienced.