• 5' Flanking Sequence Mutations Associated With Low Expression of Fetal Y-Globin Genes

      Brinson, Eleanor Campbell; Department of Cell and Molecular Biology (1988-06)
    • 96 plays a role in the virulence of C. jejuni

      Rathbun, Kimberly M; Department of Medicine (2009-05)
      Campylobacter jejuni is a gastrointestinal pathogen of humans but part of the normal flora of poultry. C. jejuni therefore grows well at both 37°C and 42°C. Proteomic studies on temperature regulation in C. jejuni strain 81-176 revealed the upregulation at 37°C of CJ0596, a predicted periplasmic chaperone that is similar to proteins found to be involved in outer membrane protein (OMP) folding and virulence in other bacteria. The cj0596 gene was highly conserved in multiple strains and species of Campylobacter (24 in total), implying the importance of this gene. To study the role CJ0596 plays in Campylobacter pathogenesis, a mutant derivative of strain 81-176 was constructed in which the cj0596 gene was precisely deleted. This mutant was complemented by restoring the gene to its original chromosomal location. The mutant strain demonstrated a decreased growth rate and lower final growth yield, yet was more motile than wild-type. The cj0596 mutant also showed altered levels of several outer membrane proteins (OMPs), and changes in membrane-associated characteristics (antimicrobial sensitivity, autoagglutination, and biofilm formation). In either single or mixed infections, the mutant was less able to colonize mice than wild-type. Purified, recombinant CJ0596 had peptidyl-prolyl cistrans isomerase (PPIase) activitty, but did not functionally complement an E. coli surA mutant. These results suggest that C. jejuni CJ0596 is a PPIase and loss of CJ0596 alters phenotypes that have been shown to be related to the pathogenesis of the bacterium.
    • Acquiring Situation Awareness through Hand-Off in a Critical Care Environment

      Holden, Tina; Nursing (Augusta University, 2019-12)
      Hand-off communication is associated with 80% of hospital errors. Situation awareness (SA) has been targeted as a strategy to reduce errors and enhance patient safety when providing hand-off communication. Few studies have focused on the influence of SA in hand-off communication in the intensive care unit where the risk of errors is high. The purpose of this study was to develop a substantive theory of critical care nursing hand-off. The study was guided by Endsley’s SA framework. A qualitative study design using Straussian grounded theory methods was used to develop a substantive theory related to critical care nursing hand-off. Data collection strategies included observation of 20 critical care nursing hand-offs followed by 34 semi-structured interviews and took place from 2017 to 2019 in a medical and surgical ICU at two academic tertiary care facilities. Data analysis was conducted using constant comparative analysis and was guided by Endsley’s model of SA. Results revealed that hand-off is a basic social process with a core category of handing-off awareness. The process contained four phases: interactive, reflective, maintenance, and preparatory. The interactive phase was characterized by communication between the giver and receiver of hand-off. During that phase, the 10 critical elements of hand-off were passed on to the receiver. These critical elements included the code status, past medical history, story, systems assessment, trends, changes, rationale, level of organ support, and anticipation. Handing off these elements in a way that flows with logical order affects awareness. Nursing behaviors of the giver associated with handing off awareness are linked to the critical elements. For the receiver, these behaviors include arriving prepared, reporting the critical elements, controlling flow, and making connections between the critical elements. Behaviors for the receiver include being an active listener, validating information, and asking questions within the flow of information. In the reflective phase, the resilient nurse bridges gaps in awareness. The maintenance phase is characterized by nursing actions that support hand-off information recall. In the maintenance phase, SA is maintained through artifacts. Artifacts are tools used by nurses to aid in the cognitive function of hand-off. The preparatory phase is characterized by information synthesis and organization. The four phases of hand-off are re-occurring and are influenced by individual and organizational factors. Individual factors include a nurse’s personal process, experience, socialization, and emotional intelligence. Organizational factors include unit policies, unit artifacts, and safety culture. Theory and research implications include the need for future research to further expand the framework of SA in hand-off, the use of qualitative methods to provide insight into complex areas of healthcare, and the need for educational interventions on SA hand-off. Practice implications include evaluation of current hand-off practices in the ICU and evaluation of organizational influences on hand-off. The study concludes that the theory of handing-off awareness in the ICU is a continuous process that occurs over four phases in a repetitive cycle that starts again with each shift change. The critical elements, flow, nursing behaviors, time, and external factors influence the ability of the nurse to achieve optimal SA.
    • Activation of Arginase and the Endothelin System in Models of Ischemic Retinopathy

      Patel, Chintan; Department of Biochemistry and Molecular Biology; Department of Biochemistry and Molecular Biology (2014-07)
      Ischemic retinopathies, such as diabetic retinopathy (DR) and retinopathy of prematurity (ROP) are characterized by microvascular degeneration, followed by an abnormal hypoxia-induced neovascularization (NV). Although the triggering insult varies among the diseases, they share a common end result of capillary loss due to increased oxidative stress, cellular inflammation and vascular injury and dysfunction. We have linked activation of the urea hydrolase enzyme arginase to the latter complications in models of DR. Both arginase and nitric-oxide synthase (NOS) enzymes utilize L-arginine as substrate. NOS dysfunction due to limitations in L-arginine availability has been implicated in the pathogenesis of diabetic complications. Our studies in streptozotocin-induced diabetic mice and high glucose treated retinal ECs have demonstrated signs of retinal vascular activation and injury. These were associated with increased arginase activity and expression, decreased bioavailable nitric oxide (NO), increased superoxide formation and increased leukostasis. Blockade of the arginase pathway prevented these alterations, suggesting a primary role of arginase in retinal vascular dysfunction and injury. Our studies have also shown that endothelium-dependent retinal vasorelaxation was impaired in diabetic mice, however, deletion of arginase improved retinal vessel function and improved blood flow. During ischemic retinopathies, disturbances in retinal blood flow can result in vasoconstriction, ischemia, tissue hypoxia and formation of neovascularization (NV). Such alterations have been linked to development of ROP, a blinding disease that adversely affects premature infants due to oxygen-induced damage of the immature retinal vasculature resulting in pathological NV. Our studies using a mouse model of ROP, the oxygen-induced retinopathy (OIR) model indicate that a potent vasoactive and angiogenic factor endothelin (EDN) is responsible for pathological NV. Our analysis revealed significant increases in EDN1, EDN2 and endothelin A receptor (EDNRA) mRNA and EDN2 protein expression during ischemia. EDN2 was localized to endothelial cells and retinal glia in OIR retinas. Treatment of OIR mice with EDNRA blocker, BQ-123, significantly increased vessel sprouting resulting in enhancement of physiological angiogenesis and decreased pathological NV. OIR triggered a significant increase in STAT3 activation and VEGFA production and increased mRNA expression of angiogenic and inflammatory mediators, which were all reduced by BQ-123 treatment. These studies suggest that EDNRA activation during OIR promotes vessel degeneration and pathological NV. Collectively, both arginase and endothelins are increased in models of ischemic retinopathies. These two pathways could be interrelated through an unknown cross-talk mechanism that needs to be elucidated.
    • Activities and Perceived Outcomes of Nurse Case Managers: Building a Case Management Model for Rural Hospitals

      Anderson-Loftin, Wanda; Department of Physiological and Technological Nursing (1996-12)
      The primary purpose of this study was to describe the activities and perceived outcomes of nurse case managers in a rural hospital setting and the relationship of nurse case managers' education, experience, and age to activities and perceived outcomes. Results of the study will be used to further develop and refine a portion of the investigator-developed model of Nursing Case Management for Rural Hospitals which served as the study framework. Nurse case managers in non-federal, rural hospitals listed in the American Hospital Association's (1995) guide to U. S. hospitals were surveyed using an investigatordeveloped instrument. Psychometric qualities of the instrument were determined as part of the study. The sample (N = 302) consisted primarily of white, middle-aged females. The majority were ADN or BSN nurses who averaged two to three years experience in case management and 16 years experience in nursing. Descriptive, correlational, and multivariate statistics were used to analyze the data. Results indicated that individual advocacy was the most frequent activity, and comments suggested that nurse case managers were becoming aware of the centrality of advocacy to their practice and job satisfaction. The second most frequent activity was teaching, with clinical practice third. The most frequent pattern of activities reflected assessment and coordination of community resources through an advocacy role for the client while performing managed care/quality assurance activities. The top ten perceived outcomes were: (a) increased patient satisfaction, (b) reduced fragmentation of care, (c) reduced length of stay, (d) increased job satisfaction, (e) increased job enjoyment, (f) increased quality of life, (g) increased functional health, (h) increased self-care, (i) increased autonomy, and (j) attainment of goals within the time-frame for reimbursement. Two-thirds of the nurse case managers thought their activities prevented delays in care and provided clients with a regular source of care, thus increasing access to care. Other significant (pi .05) findings indicated: (a) ADN, BSN, and MSN nurse case managers engaged in more teaching than nurse case managers with diplomas, (b) system advocacy was higher for MSN than for diploma, ADN, or BSN case managers, and (c) experienced nurse case managers engaged in more clinical practice than inexperienced nurse case managers.
    • Activity-Dependent Regulation of the Dopamine Transporter is Mediated by Cam Kinase II Signaling

      Padmanabhan, Shalini; Department of Pharmacology (2009-01)
      Dopamine signaling in the brain governs a variety of functions such as locomotor activity, reward, attention and working memory. The dopamine transporter (DAT) plays a crucial role in the clearance of extracellular dopamine and thus helps terminate dopamine neurotransmission. DAT is also the target for psychostimulant drugs of abuse and therapeutic agents. Changes in DAT expression occur in neuropsychiatric disorders such as attention deficit hyperactivity disorder (ADHD) and chronic psychostimulant use, and variability in DAT abundance is associated with differences in working memory. However, mechanisms regulating DAT expression are poorly understood. We tested the hypothesis that neuronal activity is one of the non-genetic determinants of DAT abundance. Chronic perturbations in neuronal firing, caused by pharmacological agents, significantly altered DAT expression and function in primary cultures of mesencephalic neurons. Pharmacological experiments showed that calcium entry through L-type voltage-gated calcium channels and calcium/calmodulindependent protein kinase II (CaMKII) activity played a role in activity-dependent changes in DAT expression. In order to further evaluate the role of CaMKII in DAT regulation, the effect of sustained depolarization, a stimulus often used to study activity-dependent changes in gene expression, on DAT expression was tested. Surprisingly, chronic KCI-induced depolarization decreased DAT expression and function. Measurement of CaMKII activity in dopamine neurons showed that chronic depolarization led to a decrease in CaMKII activity, even in the presence of elevated intracellular calcium, due to activation of the serine/threonine protein phosphatase 2A. Moreover, increasing CaMKII activity in dopamine neurons by introducing a constitutively active CaMKII mutant caused a significant increase in DAT abundance while inhibiting CaMKII activity in dopamine neurons using a dominant-negative CaMKII mutant decreased DAT abundance suggesting that CaMKII activity is both sufficient and required to cause changes in DAT expression in a cell autonomous fashion. Taken together, our data demonstrate that CaMKII activity can govern DAT expression and may play an important role in dopamine neurotransmission in the brain.
    • Adoption of AACN Verification of Feeding Tube Placement Practice Alert by Critical Care Nurses

      Bourgault, Annette M.; Department of Nursing; Georgia Regents University (2012-04)
      The intent of clinical practice guidelines is to help bridge gaps between evidence and practice, yet there is no correlation between availability of guidelines and changes in practice. Little is known about how critical care nurses adopt guidelines, since few studies have sampled nurses exclusively. This descriptive, exploratory study examined factors influencing adoption of the American Association of Critical-Care Nurses (AACN) Verification of Feeding Tube Placement Practice Alert and four clinical practices recommended by this guideline.
    • Adoption of AACN verification of feeding tube placement practice alert by critical care nurses

      Bourgault, Annette M/; College of Graduate Studies (2012-04)
      The intent of clinical practice guidelines is to help bridge gaps between evidence and practice, yet there is no correlation between availability of guidelines and changes in practice. Little is known about how critical care nurses adopt guidelines, since few studies have sampled nurses exclusively. This descriptive, exploratory study examined factors influencing adoption of the American Association of Critical-Care Nurses (AACN) Verification of Feeding Tube Placement Practice Alert and four clinical practices recommended by this guideline. An online questionnaire, based on Rogers' Diffusion of Innovations conceptual framework was completed by 370 critical care nurses from 45 states. Fifty five percent were aware of the Practice Alert and 45% had adopted the guideline in practice. Only · 24% of nurses who adopted the guideline had also adopted/implemented all four clinical practices. Practice adoption ranged from 23-94%, although 10-73% of nurses indicated partial adoption, performing practices only some of the time. There was also a gap between nurses being aware of practices (60-98%) and adopting the practices (23-94%). Predictors of AACN Verification of Feeding Tube Placement Practice Alert adoption measured by logistic regression included BSN or higher nursing education (OR · = 2.49), and the guideline characteristics of observability (OR = 1.46) and trialability (OR= 1.37). Predictors of clinical practices included membership in a professional association (OR= 4.09), staff nurse/charge nurse role (OR= 4.01), traditional communication behavior (OR= 2.83), research/web-based communication behavior (OR = 2.11 ), academic medical center (2.11 ), and perception of a policy. Policy was the only significant predictor of all four practices (OR 7.08, 42.71, 17.09, 2.78 respectively). Only practice four, avoidance of auscultation by air bolus method, was associated with Practice Alert adoption, although this was not significant when other practice guidelines were controlled for. Factors influencing nurses' decisions to adopt guidelines within an organization are multifaceted. More research is necessary to obtain a better understanding of these factors to achieve the ultimate goal of increasing translation of evidence into clinical practice.
    • Adrenal Zona Glomerulosa Targeting in Transgenic Mice

      Parmar, Jeniel; Department of Physiology (2009-12)
      The final step in the production of aldosterone is performed by the enzyme aldosterone synthase (CYP11B2). CYP11B2 is primarily expressed in the zona glomerulosa (ZG) of the adrenal cortex. Adrenocortical expression of CYP11B2 is primarily regulated by circulating levels of angiotensin II (Ang II) and K+, but the molecular mechanisms that control its ZG-specific expression are not clearly defined. Considerable in vitro analyses have been performed towards defining the mechanisms that control CYP11B2 expression. Previous studies from our laboratory and others have identified several c/s-regulatory elements on the 5' flanking promoter region (at -71/64, -129/114, -351/343 and -773/766) that regulate basal expression as well as maximal stimulation of CYP11B2 gene transcription. Moreover, key transcription factors that bind these c/s-regulatory regions including NGFIB, NURR1, SF-1 and COUP-TF have also been identified. Hence, through several in vitro analyses, a considerable evidence exists supporting the contention that these regulatory elements found within the 5' flanking promoter region may control ZG-specific expression of CYP11B2 gene. However, thus far, all evidence is based on in vitro analyses of transcriptional regulation, which does not always depict in vivo occurrences. To initiate our in vivo assessment of CYP11B2 promoter, we began by comparing the DNA sequences between human, mouse, and rat CYP11B2 genes, which interestingly revealed high sequence similarity in the 5' flanking promoter region of the CYP11B2 gene. This result suggested that the cisregulatory regions identified by in vitro analyses likely plays an important role in CYP11B2 ZG-specific gene expression. Therefore, we generated transgenic mouse lines by pronuclear injection of a Transgenic (Tg) DNA construct containing 985 base pairs (bp) of the mouse Cyp11b2 promoter driving expression of a LacZ reporter gene. Importantly, 4 founder Tg mouse lines revealed LacZ expression exclusively in the adrenal ZG. Mice fed a normal sodium diet (0.3 %) and a low sodium diet (0.03 %) showed LacZ mRNA expression exclusively in adrenal tissue. Furthermore, (3-galactosidase protein (the product of LacZ) was localized solely in the ZG of the Tg mice. Hence, the role of the proximal promoter region of the Cyp11 b2 gene was confirmed, in vivo, as this region allowed induction of LacZ exclusively in the adrenal ZG of Tg mice. Moreover, with the expression of LacZ properly restricted to adrenal ZG, we concluded that regions required for Cyp11b2 gene repression in the adjacent inner two zones of the adrenal cortex were also confined within the 985 bp promoter. This regulatory fragment will be an invaluable tool for adrenal ZG targeting of genes believed to play a role in adrenocortical diseases and aldosterone dysregulation. While developing Tg mice, we also focused on characterization and development of novel adrenocortical cell lines. As aforementioned, in vitro culture models have allowed a multitude of studies that have broadened our understanding of normal adrenocortical endocrine function. Primary cultures of adrenocortical cells have been an excellent source for in vitro studies. However, the eventual onset of senescence in primary cultures of cells creates a recurring need for the costly and difficult isolations of fresh adrenocortical cells. Hence, the use of primary cultures has been increasingly supplemented by immortalized cell lines. We utilized an adrenocortical carcinoma to develop a human adrenocortical cell line. We entitled it the human adrenocortical carcinoma cell line clone 15 (HAC15). HAC15 represents only the second human adrenocortical cell line available that exhibits physiological hormonal responses, steroidogenesis, and expression of steroid-metabolizing enzymes. The ability of HAC15 to respond to Ang II, K+, and ACTH makes it the first adrenal cell line capable of responding to the three main physiologic regulators of the adrenal cortex.
    • AKAP350 Targets to the Golgi Apparatus Where it Interacts with CLIC5B and CIP4/S

      Shanks, Ryan; Department of Biochemistry and Molecular Biology (2002-03)
      A-kinase anchoring proteins (AKAPs) are defined by their ability to scaffold PKA, but their function depends upon their targeting of PKA and other scaffolded signaling proteins to specific subcellular compartments. We have investigated one AKAP, AKAP350, which can scaffold a number of protein kinases and phosphatases at the centrosome and the Golgi apparatus. The AKAP350 gene is multiply spliced to create three carboxyl terminal splice variants which we have designated AKAP350A, AKAP350B and AKAP350C. Immunocytochemistry in HCA-7 cells demonstrated that AKAP350A was localized specifically to the Golgi apparatus. GFP-fusion proteins representing the carboxyl terminus of AKAP350A identified a carboxyl terminal region responsible for the Golgi apparatus targeting of AKAP350A. Yeast two-hybrid analysis was utilized to screen a rabbit gastric parietal cell library with a 3.2kb segment of AKAP350 (nucleotides 3611-6813) which is weakly homologous to pericentrin. This screen yielded two positive clones representing rabbit chloride intracellular channel 1 (CLIC1) and rabbit Cdc42 interacting protein 5 (CIP5). Further yeast-two hybrid binary analysis determined that CLIC1 and CIP5 bound to AKAP350 through adjacent domains located with in the PHR. CLIC1 belongs to a family of proteins which all contain a high degree of homology in their carboxyl termini, and this conserved domain is responsible for several CLIC family member’s ability to bind AKAP350. We isolated the human homologue of bovine p64, CLIC5B, from an HCA-7 colonic adenocarcinoma cell cDNA. A splice variant of CLIC5, the predicted molecular weight of CLIC5B corresponds to the molecular weight of a major CLIC immunoreactive protein in HCA-7 cells. Immunocytochemistry determined that CLIC5B colocalized with AKAP350 at the Golgi apparatus. Yeast-two hybrid binary analysis determined that the final 120 amino acids of CLIC5B interacted with AKAP350. Furthermore, expression of a GFP-fusion protein containing the final 120 amino acids targeted to the Golgi apparatus in HCA-7 cells. CIP5 contains high homology to the human protein Cdc42 interacting protein 4 (CIP4). Yeast-two hybrid binary analysis determined that the first 117 amino acids of both human CIP4 and CIP5 interacted with AKAP350. Immunocytochemistry in HCA-7 cells determined with an antibody recognizing CIP4 and CIP5 localized to the Golgi apparatus. These results suggest that AKAP350 associates with CLIC proteins and CIP4/5, and these proteins interact with the AKAP35A splice variant at the Golgi apparatus.
    • AKAP350: A Centrosome Associated Scaffold Protein

      Schmidt, Hank; Department of Biochemistry and Molecular Biology (2000-06)
      A-kinase anchoring proteins (AKAPs) are recognized as key components of compartmentalization and transduction in intracellular cAMP signaling. They allow localization of the Type II c AMP-dependent protein kinase to specific subcellular domains, effectively positioning the enzyme near its substrate to await activation by cAMP. The role of AKAPs as protein scaffolds allows binding of multiple enzymes, regulatory molecules, and structural elements, functioning as a virtual platform for modulation of specific cellular events (i.e. membrane channel activity, receptor clustering). We have cloned a novel 350 kDa AKAP (AKAP350) from human gastric cDNA, and identified partial clones in human lung and rabbit parietal cells. The genomic region containing AKAP350, found on chromosome 7q21, is multiply spliced, producing at least three distinct AKAP350 isoforms as well as yotiao, an NMDA receptorassociated protein. We identified three unique AKAP350 C-termini (AKAP350A, -B, and -C) resulting from alternative splicing of the 3' end of the gene. AKAP350 is associated with centrosomes, as well as with the cleavage furrow during anaphase and telophase by immunocytochemistry. Polyclonal antibodies to individual AKAP350 Cterminal splice variants demonstrate tissue dependent combinations of centrosomal and non-centrosomal distribution. In the polarized HCA-7 colon cell line AKAP350A is purely non-centrosomal while AKAP350B and -C are centrosomal. Anti-AKAP350C is limited to mitotic cells, suggesting that this isoform may be expressed only at entry into M phase. A yeast two-hybrid screen of a rabbit parietal cell library identified a novel TACC (Transforming Acidic Coiled coil Containing) protein family member as a ligand of the final pair of arginine residues in the AKAP350A splice variant. A GFP fusion with the novel AKAP interacting protein verified co-localization with AKAP350 at the centrosome exclusively during mitosis. Microinjection of dividing sea urchin embryos with GST fused to the AKAP interacting protein arrested cell division. Therefore, the AKAP350 protein scaffold may function as a large docking station, providing kinase / phosphatase signals for coordination of cytoskeletal dynamics as well as cell division.
    • Alpha-Tocopherol as an Ergogenic Factor in the Guinea Pig

      Allen, Hugh Clement; Department of Anatomy (1968-06)
    • Alterations in Articular Cartilage of the Rabbit Mandibular Condyle Following Surgical Induction of Anterior Disc Displacement: Light and Electron Microscopic Immunocytochemistry Using Colloidal Gold Conjugates

      Choi, Won-Seok; Department of Oral Biology (1996-05)
      The purpose of this study was to test the hypothesis that surgical induction of anterior disc displacement (ADD) in the rabbit craniomandibular joints (CMJ) will lead to degenerative osteoarthritic changes detectable a t the molecular, subcellular and cellular levels in the articular cartilage of the rabbit mandibular condyle. Ultrastructural features of the normal rabbit mandibular condyle were compared to those of experimental condyles a t two weeks following induction of ADD. The quantities of type-VI and -IX collagens, as well as the components of proteoglycans, such as chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S), k e ra tan sulfate (KS) and link protein (LP) were measured using immunogold labeling technique at the light and the electron microscopic levels. The right joint of each of 20 rabbits was exposed surgically, and all discal attachments were severed except for th e posterior attachment. The disc was then displaced anteriorly and sutured to the zygomatic arch. The left joint served as a sham -operated control. Ten additional joints were used as non­ operated controls. Deeply anesthetized rabbits were perfused with 2% buffered formalin two weeks after surgery. The mandibular condyles were excised and decalcified in ethylenediam inetetraacetic acid (EDTA). Paraffin embedded tissues were sectioned a t 5 (im for light microscopic study, while water-soluble plastic embedded sections were used for electron microscopy. Sections were incubated in monoclonal antibodies directed against C4S, C6S, KS and LP, and in polyclonal antibodies against type-VI and -IX collagens. After incubation in the appropriate colloidal gold conjugated secondary antibodies, tissue sections were studied with light and electron microscopes. In addition, immunostaining for proliferating cell nuclear antigen (PCNA) was performed using paraffin sections, and the PCNA indices of control and experimental condyles were determined. Pathological alterations were obvious in the experimental condyles, and appeared to be characteristic osteoarthritic changes. These include cartilage neovascularization, chondrocyte clustering, vacuolation, loss of extracellular matrix next to the membranes of chondrocytes, and an increase in num ber of apoptotic chondrocytes. Increased num bers of PCNA-positive cells in the osteoarthritic cartilage of the experimental group indicated a n active chondrocytic proliferation. Ultrastructural changes in injured chondrocytes included increased amounts of RER and Golgi, suggesting an increase in the synthesis and secretion of possibly degradative enzymes with a decrease in the normal secretory products. The results of th e immunocytochemistry using colloidal gold conjugates both a t the light and electron microscopic levels showed statistically significant depletion of C4S, C6S, KS, LP, type-VI collagen and type-IX collagen in the osteoarthritic cartilage (P < 0.05). The reduction of binding molecules such as LP, type-VI and type-IX collagens suggest a possible mechanism for the observed loss of integrity of the extracellular matrix. It is concluded that surgical induction of ADD in the rabbit CMJ leads to molecular, cellular and extracellular alterations in the articular cartilage of the mandibular condyle similar to those described previously in hum an ADD and in osteoarthritis of other synovial joints. The results of this study provide evidence that the loss of the shock absorber function of the disc, and the exposure of the condyles to overloading may cause the injured chondrocytes to secrete degenerative cytokines as indicated by the loss of proteoglycans, binding collagens and LP. These molecular changes are expressed a t the subcellular and cellular levels as osteoarthritis or degenerative joint disease.
    • Amyloid Peptide-a7 Nicotinic Acetylcholine Receptor Interactions: Implications For Cytoprotection In Vitro

      Li, Xinyu D.; Department of Cellular Biology and Anatomy (2006-11)
      Brain deposition of (3-amyloid peptide 1-42 (A(31 -42)-containing senile plaques has been a consistent finding in Alzheimer’s disease (AD). However, the link between Apl-42 and neuronal degeneration remains unclear. It has been reported that AP peptides bind with selectivity to a l nicotinic acetylcholine receptors (a7nAChRs), in both healthy and Alzheimer’s Diseased brain tissues. The goal of this study was to demonstrate the functional inhibition of oc7nAChRs induced by Api-42, both in systems in vitro and in vivo. Initially, differentiated PC-12 cells were preloaded with fura 2-AM and intracellular free Ca2+ levels were determined by fluorescent imaging. Nicotine-induced Ca2+ signals were inhibited by pretreatment with the a7nAChR-selective antagonists, abungarotoxin (BTX) and methyllycaconitine (MLA). Nicotine induced Ca2+ influx was also blocked by pretreatment with 100 nM Api-42. In the same model, nicotine produced a concentration-dependent increase in cell viability in differentiated PC-12 cells that underwent nerve growth factor (NGF) withdrawal for 24 hr. The cytoprotective action of nicotine was efficiently antagonized by co-treatment with a7nAChR antagonists. A concentration-dependent inhibition of the cytoprotective action of nicotine also was produced by co-treatment with Apl-42 (1-100 nM). Also in differentiated PC-12 cells, nicotine induced a concentration-dependent increase in cell surface Trk A receptor expression. This increase was almost completely reversed by a7receptor-selective antagonists, and by co-treatment with Api-42. In in vivo studies with rats, intracerebroventricular (icv) injection of choline, a selective a7nAChR agonist, produced transient, but dose-dependent pressor responses and prolonged decreases in heart rate. Icv pretreatment with BTX and MLA significantly inhibited the cardiovascular responses to subsequent injection of choline. Pretreatment with the Api-42 also significantly inhibited the choline-induced cardiovascular changes suggesting that the peptide can block an oc7nAChR-mediate response in vivo. Nicotine also was administered to rats by direct injection into a lateral cerebral ventricle. Estimation of Trk A expression in necropsied brain tissues revealed significant increases in hippocampus and entorhinal cortex. These increases were significantly inhibited in rats co-treated with a-bungarotoxin or with Api-42. The data derived from these in vitro and in vivo experiments support the hypothesis that low physiological concentrations of AP peptides inhibit the function of a7nAChRs, thereby contributing to the loss in neuronal viability that accompanies Alzheimer’s disease.
    • An Iterative Procedure to Select and Estimate Wavelet-Based Functional Linear Mixed-Effects Regression Models

      Lundeen, Jordan Sarah; Biostatistics (Augusta University, 2019-12)
      Actigraphy is the continuous long-term measurement of activity-induced acceleration by means of a portable device that often resembles a watch and is typically worn on the wrist. Actigraphy is increasingly being used in clinical research to measure sleep and activity rhythms that might not otherwise be available using traditional techniques such as polysomnography. Actigraphy has been shown to be of value when assessing circadian rhythm disorders and sleep disorders and when evaluating treatment outcomes. It can provide more objective information on sleep habits in the patient's natural sleep environment than using the patient's recollection of their activity or a written sleep diary. We propose a wavelet-based functional linear mixed model to investigate the impact of functional predictors on a scalar response when repeated measurements are available on multiple subjects. The advantage of the proposed model is that each subject has both individual scalar covariate effects and individual functional effects over time, while also sharing common population scalar covariate effects and common population slope functions. An iterative procedure is used to estimate and select the fixed and random effects by utilizing the partial consistency property of the random effect coefficients and selecting groups of random effects simultaneously via the smoothly clipped absolute deviation (SCAD) penalty function. In the first study of its kind, we compare multiple functional regression methods through a large number of simulation parameter combinations. The proposed model is applied to actigraphy data to investigate the effect of daily activity on Hamilton Rating of Depression Scale (HRSD), Insomnia Severity Index (ISI) and Reduced Morningness- Eveningness Questionnare (RMEQ) scores.
    • An Analysis of Diabetes Predictors and Diagnostic Tests in a Sample of African Americans at Risk for Diabetes

      Williams, Lovoria B.; Department of Biobehavioral Nursing (2011-05)
      Recently the ADA and International Expert Committee (IEC) endorsed HbA1C for diagnosis of glucose states. Concerns exists regarding discordance between fasting plasma glucose (FPG) and HbA1C; the committees do not agree on the HbA1C cut-point for diagnosis of sub-diabetic states; and the HbA1C may be more sensitive in AAs. A secondary data analysis of the Fit Body and Soul (FBAS) sample (n = 393) was conducted. FPG and HbA1C values were classified by the current ADA and the IEC HbA1C criteria. A risk factor analysis was also conducted. Results indicate different subject classification based on choice of diagnostic test and criterion used. Subjects classified as normoglycemic based on ADA FPG, ADA HbA1C and IEC HbA1C criterion were (78.9%; 30.7%; 55%) of the sample, respectively. Sub-diabetic state was (18.1%; 55.9%; 31.5%), respectively. Diabetes was (3%; 13.4%; 13.4%), respectively. Moderate correlation exists between HbA1C and FPG (Pearson’s r = 0.63 p < 0.001); there is only slight to fair agreement between ADA HbA1C and ADA FPG classifications and IEC HbA1C and ADA FPG classifications; Cohen’s Kappa = 0.127; 0.234 (p < 0.001), respectively; McNemar’s Chi Square (χ23df = 182.8; 81.54 p < 0.001) respectively. Significant predictors of HbA1C by linear regression were waist circumference (WC) and age; FPG predictors were age, WC and family history of diabetes. The risk factor analysis indicated poor agreement with either diagnostic test.