• Correlation of Deph of Solvent Resistance with Monomer Conversion

      Keller, Elizabeth; Rueggeberg, Frederick A.; Department of Restorative Sciences (2017-03)
      In the mouth, inadequately cured dental restorative materials may lead to detrimental consequences in their longevity. As light travels through these photo-curable restorative composites, there is an exponential decrease in light penetration with depth, and therefore the extent of local polymerization is compromised. This phenomenon is termed the “Depth of Cure” issue, which restricts the thickness if increment that each restorative material can be placed and polymerized. The purpose of this research is to develop an easily performed test that provides a correlational value between visually identifiable transition zones within acetone-sonicated, sectioned, cured composite specimens and the extent to which a composite has reached maximal monomer conversion values, to ultimately determine adequacy of polymerization at the depth of cure for certain restorative materials. This test method, proven to be independent of composite type, will be submitted to the working group associated with the revision of the International Organization for Standards Organization 4049 standard, for consideration of further testing and perhaps replacement of the current method. This research provides a fulfillment of the requests from well-respected dental clinicians to provide a clinically relevant and meaningful depth of cure test.
    • Di-N-Octylphthalate Acts as a Proliferative Agent in Murine Cell Hepatocytes by Regulating the Levels of Pro-Apoptotic Proteins

      Pruitt, Allison; Miller, Laurence; Wiley, Faith; Department of Biological Sciences (2017-03)
      Hepatocellular carcinoma (HCC) is the fifth most common cancer in the US. Its development is thought to be associated with inactivation of tumor suppressors by methylation. Di-n-octylphthalate (DNOP), a common plasticizer, is believed to cause hepatic pre-neoplastic lesions. Because a number of tumor suppressors are shown to be not expressed in HCC, our goal was to identify tumor suppressor genes methylated upon treatment with 0.1 % DNOP at 24, 48, 72 h in mouse hepatocytes cell line AML-12 and isolated primary cultured mouse hepatocytes. None of tumor suppressors experienced a change in the methylation status in presence of DNOP. Because we found that DNOP causes an increase in cell proliferation, we studied whether the effect is paralleled to a suppression of apoptosis. We found that DNOP causes a decrease in pro-apoptotic proteins and no change in anti-apoptotic proteins. We studied the physiological effects of DNOP in mouse liver. Mice were treated with 0.1 % DNOP for a month. DNOP caused a decrease in bile secretion and an increase in the hepatic levels of bile acids and glutathione. Avoiding the use of DNOP as a plasticizer in products for human consumption can reduce the incidence of diseases related to its hepatotoxicity.
    • Effectors Implicated in the Adenylyl Cyclase 1 Inhibitory Effect on Cell Migration in Pancreatic Cancer Cells

      Medepalli, Vidya; Department of Biologic Sciences (2017-03)
      Pancreatic adenocarcinoma is among the most aggressive of all cancers in the United States. Cyclic adenosine monophosphate (cyclic AMP) is a second messenger that regulates the proliferation and migration of pancreatic cancer cells. Cyclic AMP is formed from cytosolic ATP by the enzyme adenylyl cyclase (AC). In the presence of forskolin, a transmembrane AC activator, the proliferation and migration of pancreatic cells have been inhibited. Since the mechanisms underlying the inhibitory effect of activated adenylyl cyclase are little understood, we investigated the downstream mediators implicated in the AC/cyclic AMP pathway. With this purpose, we overexpressed AC1 in the human pancreatic adenocarcinoma (HPAC) cell line, and through the protein kinase A (PKA) inhibitor H-89 and the exchange protein directly activated by cyclic AMP (EPAC) inhibitor ESI-09, we assessed the effector involved upon the treatment with forskolin. In a previous study, we showed that PKA alone mediates the inhibitory effect of forskolin/AC1/cyclic AMP on proliferation of HPAC cells. In the present study, we examined the effectors implicated in the AC1 inhibitory effect on cell migration through utilization of the CytoSelect 24-well cell migration assay kit. Our current experimental data suggests that PKA and EPAC are both likely to be downstream mediators in the effect of forskolin/AC1/cyclic AMP on migration of HPAC cells.
    • The Efficacy of Socially Housing Geriatric Monkeys with a Long History of Single Housing

      Callaway, Karen; Saul, Bruce; Department of Biological Sciences (2016-03)
      Nonhuman primates (NHP) play a significant role in scientific research with issues ranging from Alzheimer's to heart disease. As scientists and veterinarians, it is critical to ensure the physical and psychological well-being of these important research animals. The 2011 Guide for the Care and Use of Laboratory Animals (Guide) states all gregarious animals in research environments should be socially housed. While the trend has been moving towards socially housing these animals, the process has been gradual, and is sometimes hindered by their research functions. Since the changes to the “Guide” are relatively recent, in addition to research-related limitations, there are adult and geriatric animals that have been singly housed the majority of their lives. NHPs singly housed for prolonged periods of time are among the most difficult to integrate socially. This project examines the efficacy of socially housing geriatric rhesus monkeys singly housed for most of their lives. We predicted (1) heterosexual pairs would yield a higher success rate than isosexual pairs and (2) overall pairing success rate would be lower in socially isolated geriatrics than for previously published reports of pairing success for younger animals without a history of social isolation. Our results were consistent with these predictions.
    • Retinopathy of Prematurity: Role of MicroRNA-21 in Pathological Newvascularization

      Rajpurohit, Shubhra; Bartoli, Manuela; Department of Biological Sciences (2017-03)
      Retinopathy of prematurity (ROP) is a disease that occurs in premature infants weighing 1250g or less. ROP causes abnormal blood vessels to grow in the retina. This growth can cause the retina to detach from the back of the eye, leading to blindness in severe cases. ROP affects approximately 14,000 infants, and 90% of those affected have only mild disease. However, 1,100-1,500 children develop disease severe enough to require medical treatment, and 400-600 infants each year in the U.S. become legally blind from ROP. To study the mechanisms of abnormal vascularization in the retina we use a mouse model of oxygen induced retinopathy (OIR), which is a standard experimental model for ROP. In mice the retinal vasculature normally starts to develop around birth and is fully mature around 3 weeks after birth. To trigger OIR, we expose 7-day-old mouse pups to hyperoxia (70% O2), which results in regression of the vasculature. When the animals are returned to room air (21% O2) after five days in oxygen, a neovascular response is triggered. MicroRNAs, short noncoding RNAs that inhibit gene expression through the post-transcriptional repression of their target mRNAs, emerged as key regulators of diverse biologic processes. In this study we will determine the role of miR-21, a specific microRNA that has been involved in pathological angiogenesis, by blocking its activity using in vivo delivery of miR-21 inhibitors (antagomiR) in a mouse model of OIR and in vitro using isolated retinal microvascular cells subjected to hypoxia. The obtained results from western blots and qPCR suggest miR-21 expression is increased and tissue inhibitor of metalloprotease-3 (TIMP3), a target gene of miR-21, expression is decreased in retinal endothelial cells exposed to hypoxia.