87 research outputs found

    Progress in rational methods of cryoprotection in macromolecular crystallography

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    Measurements of the average thermal contractions (294→72 K) of 26 different cryosolutions are presented and discussed in conjunction with other recent advances in the rational design of protocols for cryogenic cooling in macromolecular crystallography

    Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions

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    Additional experimental evidence is presented for in vitro generation of hydroxyl radicals because of redox cycling of environmentally persistent free radicals (EPFRs) produced after adsorption of 2-monochlorophenol at 230 °C (2-MCP-230) on copper oxide supported by silica, 5% Cu(II)O/silica (3.9% Cu). A chemical spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed. Experiments in spiked O17 water have shown that ∼15% of hydroxyl radicals formed as a result of redox cycling. This amount of hydroxyl radicals arises from an exogenous Fenton reaction and may stay either partially trapped on the surface of particulate matter (physisorbed or chemisorbed) or transferred into solution as free OH. Computational work confirms the highly stable nature of the DMPO–OH adduct, as an intermediate produced by interaction of DMPO with physisorbed/chemisorbed OH (at the interface of solid catalyst/solution). All reaction pathways have been supported by ab initio calculations

    A Novel Peptide Derived from Human Apolipoprotein E Is an Inhibitor of Tumor Growth and Ocular Angiogenesis

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    Angiogenesis is a hallmark of tumor development and metastasis and now a validated target for cancer treatment. We previously reported that a novel dimer peptide (apoEdp) derived from the receptor binding region of human apolipoprotein E (apoE) inhibits virus-induced angiogenesis. However, its role in tumor anti-angiogenesis is unknown. This study demonstrates that apoEdp has anti-angiogenic property in vivo through reduction of tumor growth in a mouse model and ocular angiogenesis in a rabbit eye model. Our in vitro studies show that apoEdp inhibits human umbilical vein endothelial cell proliferation, migration, invasion and capillary tube formation. We document that apoEdp inhibits vascular endothelial growth factor-induced Flk-1 activation as well as downstream signaling pathways that involve c-Src, Akt, eNOS, FAK, and ERK1/2. These in vitro data suggest potential sites of the apoE dipeptide inhibition that could occur in vivo

    Impact of intracellular ion channels on cancer development and progression

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    v Optical Navigation: Comparison of the Extended Kalman Filter and the Unscented Kalman Filter

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    in all of my adventures. Acknowledgments I am forever grateful for my parents. They have always given me unconditional love and support that I will always appreciate. I would also like to thank the Aerospace Engineering Department for encouraging this endeavor. Specifically, I am very grateful to Dr. Robert Bishop for providing me financial and academic support during my graduate studies. I am very appreciative of my reader, Dr. Maruthi Akella, for taking the time to approve this thesis. I also want to thank Kyle DeMars for sharing his vast knowledge of navigation systems with me at any time of the day. I am very thankful for the encouragement from my friends during this journey, specifically Paige Felker and Bryan Yocom

    Kaposi\u27s Sarcoma-Associated Herpesvirus G-protein Coupled Receptor Activates the Canonical Wnt/β-catenin Signaling Pathway.

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    Abstract Background: KSHV is a tumorigenic γ-herpesvirus that has been identified as the etiologic agent of Kaposi\u27s sarcoma (KS), a multifocal highly vascularized neoplasm that is the most common malignancy associated with acquired immunodeficiency syndrome (AIDS). The virus encodes a constitutively active chemokine receptor homologue, vGPCR that possesses potent angiogenic and tumorigenic properties, and is critical for KSHV pathobiology. To date, a number of signaling pathways have been identified as key in mediating vGPCR oncogenic potential. Findings: In this study, we identify a novel pathway, the Wnt/β-catenin pathway, which is dysregulated by vGPCR expression in endothelial cells. Expression of vGPCR in endothelial cells enhances the nuclear accumulation of β-catenin, that correlates with an increase in β-catenin transcriptional activity. Activation of β-catenin signaling by vGPCR is dependent on the PI3K/Akt pathway, as treatment of vGPCR-expressing cells with a pharmacological inhibitor of PI3K, leads to a decreased activation of a β-catenin-driven reporter, a significant decrease in expression of β-catenin target genes, and reduced endothelial tube formation. Conclusions: Given the critical role of Wnt/β-catenin signaling in angiogenesis and tumorigenesis, the findings from this study suggest a novel mechanism in KSHV-induced malignancies

    Serum-Deprived Human Multipotent Mesenchymal Stromal cells (MSCs) are Highly Angiogenic.

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    Recent reports have indicated that mesenchymal stromal cells (MSCs) from bone marrow have a potential in vascular remodeling and angiogenesis. Here, we report a unique phenomenon that under serum-deprived conditions MSCs survive and replicate. Secretome analysis of MSCs grown under serum-deprived conditions (SD-MSCs) identified a significant upregulation of prosurvival and angiogenic factors including VEGF-A, ANGPTs, IGF-1, and HGF. An ex vivo rat aortic assay demonstrated longer neovascular sprouts generated from rat aortic rings cultured in SD-MSC-conditioned media compared to neovascular sprouts from aortas grown in MSC-conditioned media. With prolonged serum deprivation, a subpopulation of SD-MSCs began to exhibit an endothelial phenotype. This population expressed endothelial-specific proteins including VEGFR2, Tie2/TEK, PECAM/CD31, and eNOS and also demonstrated the ability to uptake acetylated LDL. SD-MSCs also exhibited enhanced microtubule formation in an in vitro angiogenesis assay. Modified chick chorioallantoic membrane (CAM) angiogenesis assays showed significantly higher angiogenic potential for SD-MSCs compared to MSCs. Analysis of CAMs grown with SD-MSCs identified human-specific CD31-positive cells in vascular structures. We conclude that under the stress of serum deprivation MSCs are highly angiogenic and a population of these cells has the potential to differentiate into endothelial-like cells
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