• Proliferative Verrucous Leukoplakia (PVL) Expresses High Levels of Toll-Like Receptor 2 (TLR2)

      Koh, Joon; Kurago, Zoya; Georgia Cancer Center (Augusta University, 2019)
      In the current study, we analyzed samples of human oral mucosal PVL and other epithelial disorders to test the possibility that, if TLR2 is involved in early stages of carcinogenesis, then keratinocytes in early-intermediate stages of PVL may express more TLR2 than keratinocytes in non-dysplastic epithelium.
    • Properties of the Force Exerted by Filopodia and Lamellipodia and the Involvement of Cytoskeletal Components

      Cojoc, Dan; Difato, Francesco; Ferrari, Enrico; Shahapure, Rajesh B.; Laishram, Jummi; Righi, Massimo; Di Fabrizio, Enzo M.; Torre, Vincent; Mei, Lin; Department of Neurology; et al. (2007-10-24)
      During neuronal differentiation, lamellipodia and filopodia explore the environment in search for the correct path to the axon's final destination. Although the motion of lamellipodia and filopodia has been characterized to an extent, little is known about the force they exert. In this study, we used optical tweezers to measure the force exerted by filopodia and lamellipodia with a millisecond temporal resolution. We found that a single filopodium exerts a force not exceeding 3 pN, whereas lamellipodia can exert a force up to 20 pN. Using metabolic inhibitors, we showed that no force is produced in the absence of actin polymerization and that development of forces larger than 3 pN requires microtubule polymerization. These results show that actin polymerization is necessary for force production and demonstrate that not only do neurons process information, but they also act on their environment exerting forces varying from tenths pN to tens of pN.
    • Protection of Rat Cardiac Myocytes by Fructose-1,6-Bisphosphate and 2,3-Butanedione

      Wheeler, Thomas J.; Chien, Sufan; McNeil, Paul L.; Department of Cellular Biology and Anatomy; College of Graduate Studies (2012-04-27)
      Earlier studies by our group showed that fructose-1,6-bisphosphate (FBP) enhances the hypothermic preservation of rat cardiac myocytes and the functional recovery of animal hearts after hypothermic storage. However, the mechanisms involved were not clear. We extended the cardiomyocyte studies by testing whether the FBP effects were due to chelation of extracellular calcium, leading to lower intracellular levels. We also tested effects of 2,3-butanedione monoxime (BDM), pyruvate, and adenine nucleotide precursors. Cardiomyocytes were incubated in ischemic suspension at 3°C, and aliquots examined over 48 to 72 hours for retention of rod-shaped morphology, a measure of viability. Cytosolic Ca2+ levels were measured in some experiments. FBP at 5 mM reduced the death rate even when added after one or two days of incubation. It caused cytosolic calcium levels that were 33% lower than controls in freshly-isolated cells and 70% lower after one day of incubation. EGTA protected against cell death similarly to FBP. These results indicated that one of the mechanisms by which FBP exerts protective effects is through chelation of extracellular calcium. BDM was strongly protective and reduced cytosolic calcium by 30% after one day of incubation. As with FBP, BDM was effective when added after one or two days of incubation. BDM may be useful in combination with FBP in preserving heart tissue. Pyruvate, adenine, and ribose provided little or no protection during hypothermia.
    • Protein Kinase D In Keratinocyte Maturation

      Dodd, M. Ernest; Department of Physiology (2004-08)
      The epidermis is important for the body's maintenance of water homeostasis and resistance to environmental stress, and the m ajor cell type of the epidermis is the keratinocyte. Keratinocyte maturation requires proliferation, followed by terminal differentiation, and diseases of the skin often exhibit deregulated epidermal maturation. Protein kinase D (PKD) expression correlates with proliferation in keratinocytes, and PKD activation occurs in response to mitogen stimulation in other cell types. W e have hypothesized that PKD functions as a pro-proliferative and/or anti-differentiative signal in primary mouse keratinocytes and have predicted that agents that stimulate differentiation might also initiate a reduction in PKD expression and/or activation to allow differentiation to proceed. Thus, changes in PKD levels, autophosphorylation and activity were analyzed upon treatment with differentiating agents and with 1 2 -0 - tetradecanoylphorbol-13-acetate, TPA, which stimulates differentiation acutely and proliferation chronically. 1,25-dihydroxyvitamin D3 -, elevated extracellular calcium-, and acute TPA-induced differentiation down-modulated PKD levels and autophosphorylation at serine 916. In addition, elevated extracellular calcium- and acute TPA-induced differentiation down-modulated PKD activity. Chronic TPA treatment stimulated proliferation and caused a recovery o f PKD levels, autophosphorylation and activity. In co-transfection experiments in keratinocytes, co-expression of PKD increased and decreased the promoter activities of keratin 5, a marker of proliferation, and involucrin, a marker of differentiation, respectively, and opposed the effects of elevated extracellular calcium on the expression of these markers. W hile cloning PKD for expression studies, we identified a splice variant of PKD, PKD{3, which is differentially spliced in a region important in activation and subcellular localization. Therefore, we hypothesized that this splice variant may have dissimilar activation properties and/or alternate roles in keratinocyte maturation. However, in vitro activation studies demonstrated equal activation of PK D a (full length) and PKDj3 by TPA and DAG. Co-transfection experiments showed that P K D a and PKDp affected marker expression to the same degree and similarly opposed the effects of elevated extracellular calcium-induced differentiation on marker expression. Our work represents the first demonstration of: 1) down-modulation o f PKD during differentiation, 2) pro-proliferative/anti-differentiative effects of PKD on keratinocyte marker expression and 3) existence of a splice variant of PKD.
    • Protein Kinase D Restrains Angiotensin II-Induced Aldosterone Secretion in Primary Adrenal Glomerulosa Cells

      Shapiro, Brian A.; Department of Physiology (2007-07)
      Misregulation of the renin-angiotensin II (Angll)-aldosterone (Aldo) system is a key feature of cardiovascular disease. A focus of study in this system is the Angll-elicited secretion of Aldo from the adrenocortical zona glomerulosa. An excellent model in which to study this phenomenon is primary cultures of bovine adrenal glomerulosa (AG) cells. These cells secrete detectable quantities of Aldo in response to secretagogues, such as Angll, elevated potassium (K+), adrenocorticotrophic hormone (ACTH) and phorbol 12-myristate 13-acetate (PMA), within 30 minutes. The serine (Ser)/threonine kinase protein kinase D (PKD) is reported to be activated by Angll in several systems, including the adrenocortical carcinoma cell line NCI H295R, and is thought to have a positive role in chronic (24 hours) Angll-evoked Aldo secretion. Because the role of PKD in acute Angll-elicited Aldo secretion has never been examined in a primary culture system, we undertook to study the role of PKD in acute (minutes to one hour) Aldo secretion. Thus, Angll (10 nM) and PMA (100 nM), but not elevated K+ (15 mM) and ACTH (10 nM), induced phosphorylation of PKD on Ser910, a marker of PKD activation, in primary bovine AG cells. This finding was confirmed by an in vitro kinase activity assay. Angll and PMA were also able to induce PKD activation in H295R cells. Furthermore, this activation was concentration dependent, and was rapidly induced (by 5 min). PKD activation was dependent on Angll type 1 (AT-1), but not AT-2 receptor, signaling, and was independent of tyrosine kinase signaling. Finally, we introduced, via adenovirus transduction, wild-type PKDwt and dominant negative PKDS738/742A constructs into primary AG cells and monitored Angll-evoked Aldo secretion. PKDwt -transduced AG cells exhibited decreased Angll-stimulated Aldo secretion, while in the PKDS738A742A - infected AG cells Angll-stimulated Aldo was enhanced. Thus, we hypothesize that PKD has an anti-secretory role in Angll-induced acute Aldo secretion.
    • PROTEIN SYNTHESIS IN PANCREAS OF FASTED PIGEONS

      Black, Owen; Webster, Paul D.; Department of Medicine; Department of Cellular Biology and Anatomy (1973-04-1)
      The regulation of protein synthesis in the pigeon has been studied by comparing the capability of cell-free amino acid incorporating systems of membrane-bound and membrane-free polysomes prepared from fasted and fed birds. New methods were developed for isolating polysomes since techniques used for other tissues did not provide quantitative recovery of polysomal RNA. The sucrose gradient profile of polysomes from pigeon pancreas showed a predominance of trisome species. Although initiation factors are present on polysomes, it was found that polysomes in cell-free systems would not initiate protein synthesis without exogenous initiation factors. This suggested the presence of an inhibitor or regulator of protein synthesis. These studies show that fasting resulted in: (a) decreased amounts of polysomes; (b) disaggregation of polysomes to monosomes; (c) decreased capability of polysomes to synthesize nascent peptides and to initiate additional synthesis, apparently not related to concentration of initiation factors.
    • Protein-Protein Interaction between G protein-coupled receptors and heterotrimeric G proteins

      Qin, Kou; Department of Pharmacology and Toxicology (2011-01)
      G protein-coupled receptors (GPCRs) interact directly with heterotrimeric G proteins to transduce physiological signals. Early studies of this interaction concluded that GPCRs (R) and G proteins (G) collide with each other randomly after receptor activation and that R-G complexes are transient (collision model). More recent studies have suggested that inactive R and G are preassembled as stable R-G complexes in cells (preassembly models). Using fluorescence recovery after photobleaching (FRAP) we examined the stability of complexes formed between cyan fluorescent protein-labeled a2Aadrenoreceptors (C-a2ARs) and G proteins in HEK293 cells. Labeled G proteins diffused in the plasma membrane with equal mobility in the absence and presence of immobile C- a2ARs. In contrast, a stable R-G interaction was detected when G proteins were deprived of nucleotides and C- a2ARs were active. Over-expression of regulator of G protein signaling 4 (RGS4) accelerated the onset of effector activation but did not alter the interaction between C- a2ARs and G proteins. At most a small fraction of C- a2ARs and G proteins exist as R-G complexes at any moment. However, applying similar technique and protocols, we demonstrated that immobilized M3R specifically decreases the mobility of Gaq heterotrimers on the plasma membranes of intact HEK293 cells, suggesting the existence of R-G preassembly. The C-terminus of M3R was determined to be both required and sufficient for preassembly. The M3R C-terminus contains a polybasic region (565KKKRRK570) located distal to the 8th a-helix domain. Substitution of this polybasic region with 6 electroneutral alanines (M3R6A) prevented preassembly. Permeabilization of cells with low ionic strength buffer resulted in enhanced R-G interaction, implicating electrostatic forces as a factor in the preassembly. We examined the functional properties of the mutant M3R6A, which showed decreases in acetylcholine potency compared with M3R. M3R6A produced active Gq at half the rate of M3R. Other Gq-coupled receptors, such as M1 and M5 muscarinic and a1a,a1b, aid adrenergic receptors, contain similar C-terminal polybasic regions. We found that both M5R and alb adrenoceptor (albAR) preassembled with Gq proteins. Our findings suggest that a polybasic regionmediated electrostatic mechanism could be a common mechanism of preassembly between Gq-coupled receptors and Gq proteins.
    • Psychosocial Factors as Predictors for Patient Outcomes in Rehabilitation of Upper Extremity Injury Caused by Trauma:

      Holley, Ashlyn; Saren, Madison; Wygle, Sarah; Deese, Abigail; Payne, Regan; Department of Occupational Therapy (Augusta University, 2020-08-26)
      At the conclusion of this presentation, attendees will be able to: 1) Explain three ways in which psychosocial factors have the ability to alter rehabilitation outcomes in individuals who have sustained a traumatic upper extremity injury, 2) Discuss two gaps in the literature regarding the impact of psychosocial factors on rehabilitation outcomes in individuals recovering from traumatic upper extremity injuries, 3) Identify two methods, strategies, or assessments to be implemented in practice in order to evaluate and address psychosocial factors as a component affecting functional outcomes of clients with traumatic UE injuries.
    • Pulmonary Stress in the Alcoholic and Obese Lung

      Thomas, Amanda Blair; Department Of Undergraduate Health Professions (Augusta University, 2015-05)
      In the United States today, alcoholism and obesity are increasingly becoming issues for a vast age group from young children to geriatric adults. Alcoholism and obesity have been extensively studied as separate entities that have been proven to change metabolism and cause over-lapping health issues, which prompted us to study them in conjunction with one another, especially in the lungs. One major link between these two alarmingly common problems is Krüppel-Like Factor 4 (KLF4), a cell regulatory protein crucial to cellular normality and monocyte differentiation. This particular study highlights the effects alcoholism and obesity have on the lung, specifically epithelial cells (L2) and macrophages (AM). The goal of this project is to measure the KLF4 expression in the L2 and AM cells subjected to high ethanol (EtOH) consumption, high glucose consumption, high EtOH and glucose consumption, as well as a healthy control lung in to explain the mechanism behind decreased immune function in these patients.
    • Purification of Recombinant Human Histone Methyltransferases for Inhibition Studies

      Jahan, Asmat; Shaikh, Zahid; Department of Chemistry & Physics (2017-03)
      Resistance to cellular apoptotic pathways is a major contributing factor in the metastasis of cancer. One such cell-intrinsic pathway which induces programmed cell death is ligand cell surface death receptors, including Fas protein. In primary colorectal cancer, Fas expression is often diminished. The silencing of Fas expression is perhaps a mechanism by which human colorectal cancer cells evade apoptosis. The decrease in Fas expression levels is associated with hypermethylation of histone 3 lysine 9 catalyzed by histone methyltransferases (HMTases) such as SUV39H1 and SUV39H2. Because of the role of methylation in silencing Fas expression, HMTase inhibitors represent potential anti-cancer agents. Verticillin A, a natural compound extracted from wild mushroom, is a broad-based HMTase inhibitor and has been shown to cause toxicity in mice. Our goal in this study is to identify specific SUV39H1 and SUV39H2 inhibitors that are less toxic than Verticillin A. To investigate this, human SUV39H1 was sub-cloned into an expression vector, transformed into an E.coli expression strain and purified using affinity chromatography. Gel electrophoresis and Western blot analysis confirmed the presence of partially purified human SUV39H1. The next phase of the project will involve testing the activity of the purified protein in an in vitro assay.
    • Quantifying Exocytosis by Combination of Membrane Capacitance Measurements and Total Internal Reflection Fluorescence Microscopy in Chromaffin Cells

      Becherer, Ute; Pasche, Mathias; Nofal, Shahira; Hof, Detlef; Matti, Ulf; Rettig, Jens; Mei, Lin; Department of Neurology; College of Graduate Studies (2007-06-6)
      Total internal reflection fluorescence microscopy (TIRF-Microscopy) allows the observation of individual secretory vesicles in real-time during exocytosis. In contrast to electrophysiological methods, such as membrane capacitance recording or carbon fiber amperometry, TIRF-Microscopy also enables the observation of vesicles as they reside close to the plasma membrane prior to fusion. However, TIRF-Microscopy is limited to the visualization of vesicles that are located near the membrane attached to the glass coverslip on which the cell grows. This has raised concerns as to whether exocytosis measured with TIRF-Microscopy is comparable to global secretion of the cell measured with membrane capacitance recording. Here we address this concern by combining TIRF-Microscopy and membrane capacitance recording to quantify exocytosis from adrenal chromaffin cells. We found that secretion measured with TIRF-Microscopy is representative of the overall secretion of the cells, thereby validating for the first time the TIRF method as a measure of secretion. Furthermore, the combination of these two techniques provides a new tool for investigating the molecular mechanism of synaptic transmission with combined electrophysiological and imaging techniques.
    • Questionnaire Design and Responsiveness in a Data Capture Tool for Student Sharing of Experiences of Statewide Clerkship Sites

      Zheng, Stephanie; Behrman, David; Agrawal, Parth; Basco, Brian; Ball, Charlotte; Rose, Jennifer; Miller, Samel; Wood, Elena (2017-03)
      Positive clerkship experiences and student performance in the clinical years has been correlated to perceived quality of education and specialty choice amongst medical students [1-3]. The Medical College of Georgia uses a distributed campus model with more than 250 clerkship rotation sites across the state and beyond, making student clerkship choices imperative to their development as physicians. We developed a survey to collect both quantitative and qualitative data from students during their clerkship years and a system to distribute that information to students. The data allowed us to evaluate the effectiveness of various question formats through responsiveness, the length of responses, and time spent on the survey. In addition to this, we looked at the number of responses per clerkship in order to see whether or not our survey was getting information about all of the 3rd year rotations. We aspire to take these findings and utilize them to expand t he program and improve the questionnaire in order to yield more responsiveness from students.
    • Rab proteins in gastric parietal cells: evidence for the membrane recycling hypothesis.

      Calhoun, Benjamin C; Goldenring, J R; Department of Medicine (1997-07-08)
      The gastric parietal cell secretes large quantities of HCl into the lumen of the gastric gland in response to secretagogues such as histamine. In the membrane recycling hypothesis, this secretory activity requires the trafficking of the gastric H+/K(+)-ATPase to the cell surface from intracellular tubulovesicles. The Rab subclass of small GTP-binding proteins is thought to confer specificity to vesicle transport throughout the secretory pathway, and previous investigations established that Rab11 is highly expressed in gastric parietal cells. Recent discoveries in intra-Golgi transport and neuronal synaptic vesicle fusion have fortuitously converged on an evolutionarily conserved protein complex involved in vesicle docking and fusion. Recent results indicate that Rab11 is involved in the apical targeting of vesicles in parietal cells and other epithelial cells throughout the gastrointestinal tract. In support of the membrane recycling hypothesis, Rab co-segregates with H+/K(+)-ATPase in parietal cells. The presence of Rab11 on tubulovesicles supports a role for this Rab protein in recycling vesicle trafficking.
    • Rabbit Anatomy: A Brief Photographic Atlas and Dissection Guide, Part 1: Muscular System (Second Edition)

      Mukhopadhyay, Soma; Ruggiero Wagner, Lisa; Augusta University, Department of Biological Sciences; Clemson University, Department of Biological Sciences (Augusta University, 2020)
    • Rabbit Anatomy: A Brief Photographic Atlas and Dissection Guide, Part 2: Cardiovascular System (Second Edition)

      Mukhopadhyay, Soma; Ruggiero Wagner, Lisa; Augusta University, Department of Biological Sciences; Clemson University, Department of Biological Sciences (Augusta University, 2020)
    • Rac1 Activation Driven by 14-3-3f Dimerization Promotes Prostate Cancer Cell-Matrix Interactions, Motility and Transendothelial Migration

      Goc, Anna; Abdalla, Maha; Al-Azayzih, Ahmad; Somanath, Payaningal R.; Department of Medicine (2012-07-13)
      14-3-3 proteins are ubiquitously expressed dimeric adaptor proteins that have emerged as key mediators of many cell signaling pathways in multiple cell types. Its effects are mainly mediated by binding to selective phosphoserine/threonine proteins. The importance of 14-3-3 proteins in cancer have only started to become apparent and its exact role in cancer progression as well as the mechanisms by which 14-3-3 proteins mediate cancer cell function remain unknown. While protein 14-3-3s is widely accepted as a tumor suppressor, 14-3-3f, b and c isoforms have been shown to have tumor promoting effects. Despite the importance of 14-3-3 family in mediating various cell processes, the exact role and mechanism of 14-3-3f remain unexplored. In the current study, we investigated the role of protein 14-3-3f in prostate cancer cell motility and transendothelial migration using biochemical, molecular biology and electric cell-substrate impedance sensing approaches as well as cell based functional assays. Our study indicated that expression with wild-type protein 14-3-3f significantly enhanced Rac activity in PC3 cells. In contrast, expression of dimer-resistant mutant of protein 14-3-3f (DM-14-3-3) inhibited Rac activity and associated phosphorylation of p21 activated kinase-1 and 2. Expression with wild-type 14-3-3f or constitutively active Rac1 enhanced extracellular matrix recognition, lamellipodia formation, cell migration and trans-endothelial migration by PC3 cells. In contrast, expression with DM 14-3-3f or DN-Rac1 in PC3 cells significantly inhibited these cell functions. Our results demonstrate for the first time that 14-3-3f enhances prostate cancer cell-matrix interactions, motility and transendothelial migration in vitro via activation of Rac1-GTPase and is an important target for therapeutic interventions for prostate cancer.
    • Race and Income Association with Health Service Utilization for Veterans with Heart Failure

      Landrum, Laurie G.; Department of Nursing (2012-07)
      Disproportionate heart failure outcomes exist for Blacks in the Veterans Health Administration (VHA) despite equitable access and financial barrier minmization. No study has examined the association of race and income with health service utilization for veterans with heart failure. This observational study investigated race and income associations with readmissions, bed days of care, and emergency room (ER) visits for veterans with heart failure after controlling for predisposing, enabling, and illness severity factors. Medical record data were collected for 149 veterans telemonitored for heart failure during 2008-2011. Heart failure symptoms severity and comorbidities were measured using investigator-adapted scales based on the New York Heart Association IIV scale and the Charlson comorbidity index. Heart failure related outcomes (30 day, 90 day, 1 year, and total readmissions, ER visits, and total bed days of care) were modeled controlling for age, marital status, and heart failure and comorbidity severity. Of patients younger than 60 years of age, 18% were Black compared to 11% of Whites, Χ2 (2, N=149) = 5.15, p= .02. Blacks had a much higher comorbidity prevalence than Whites, p = .000. Ischemic heart disease and chronic kidney disease rates were double and triple national VHA rates, respectively, among Whites and Blacks. Race did not predict readmissions, bed days of care, or ER visits. The odds of a readmission or bed day of care ever decreased by 38% and 43%, respectively, for married men, p = .03. The odds of a readmission or bed day of care ever due to severe heart failure—compared to less severe heart failure—were four to five times higher, respectively, p ≤ .004. Income increased the odds of total bed days of care by 14%, p = .00, holding race constant. Overall, the sample experienced far fewer readmissions, bed days of care, or ER visits, compared to VHA national rates, but sample size may have limited accurate comparisons.
    • Racial Dissimilarities as a Social Determinant of Health Outcomes: Evidence from Counties in the State of Georgia

      Lee, Divesia; Hull College of Business; Department of English & Foreign Languages; Medcalfe, Simon; Slade, Catherine; Hoffman, Todd; Augusta University (2019-02-13)
      Social determinants of health account for about 50 percent of health outcomes- more than any other category, yet is the most understudied, therefore warranting further investigation. We contend that within social determinants of health, analysis of racial segregation is of importance. Racial segregation is a structural form of racism, where people of similar race live in communities apart from people of other races. Prior studies have used a dissimilarity index to measure racial segregation and its impact on health outcomes, and has suggested that racial residential segregation has a negative impact on health outcomes, but none of these studies have focused on county level data or the State of Georgia in particular. Using a dataset from the Robert Wood Johnson Foundation, supplemented by other public health and demographic data for all counties in Georgia, we use regression analysis to model the relationship between segregation and various health outcomes. A variety of social determinants of health were analyzed ranging from factors of economic stability, neighborhood and physical environment, and education, to aspects of the healthcare system. Initial results suggest that racial segregation relates to health outcomes, but it depends on the health outcomes being measured. Conclusions are pending further quantitative analysis.
    • Racial Segregation as a Social Determinant of Health Outcomes: Evidence from Counties in the State of Georgia

      Lee, Divesia; Department of Finance and Economics, Department of English & Foreign Languages (Augusta University, 2019-05)
      Social determinants of health account for about 50 percent of health outcomes- more than any other category, yet is the most understudied, therefore warranting further investigation. We contend that within social determinants of health, analysis of racial segregation is of importance. Racial segregation is a structural form of racism, where people of similar race live in communities apart from people of other races. Prior studies have used a dissimilarity index to measure racial segregation and its impact on health outcomes, and has suggested that racial residential segregation has a negative impact on health outcomes, but none of these studies have focused on county level data or the State of Georgia in particular. Using a dataset from the Robert Wood Johnson Foundation, supplemented by other public health and demographic data for all counties in Georgia, we use regression analysis to model the relationship between segregation and various health outcomes. A variety of social determinants of health were analyzed ranging from factors of economic stability, neighborhood and physical environment, and education, to aspects of the healthcare system. Initial results suggest that racial segregation relates to health outcomes, but it depends on the health outcomes being measured. Conclusions are pending further quantitative analysis.
    • A Randomized Preventive Rehabilitation Trial in Advanced Head and Neck Cancer Patients Treated with Chemoradiotherapy: Feasibility, Compliance, and Short-term Effects

      van der Molen, Lisette; van Rossum, Maya A.; Burkhead, Lori M.; Smeele, Ludi E.; Rasch, Coen R. N.; Hilgers, Frans J. M.; Department of Otolaryngology (2010-07-11)
      Keywords: Head and neck cancer