Expression of ciliary neurotrophic factor and its receptor in experimental obstructive nephropathy

Ciliary neurotrophic factor (CNTF) is well known as a growth/survival factor of neuronal tissue. We investigated the expression of CNTF and its specific receptor alpha (CNTFRα) in a unilateral ureteral obstruction (UUO) model. Complete UUO was produced by left ureteral ligation in Sprague-Dawley rats. The animals were sacrificed on days 1, 3, 5, 7, 14, 21, and 28 after UUO. The kidneys were fixed, and processed for both immunohistochemistry and in situ hybridization. CNTF immunoreactivity in sham-operated kidneys was observed only in the descending thin limb (DTL) of the loop of Henle. In UUO kidneys, CNTF expression was induced in the S3 segment (S3s) of the proximal tubule from day 1, and progressively expanded into the entire S3s and a part of the convoluted proximal tubules, distal tubules (DT), and glomerular parietal epithelium up to day 7. Upregulated CNTF expression was maintained to day 28. From day 14, the inner medullary collecting duct showed weak CNTF immunoreactivity. The CNTFRα mRNA hybridization signal in sham-operated kidneys was weakly detected in the DTL, DT, medullary thick ascending limb, and in a few S3s cells. After UUO, CNTFRα mRNA expression increased progressively in both the renal cortex and the medulla up to day 7 and increased expression was maintained until day 28. The results suggest that the S3s may be the principal induction site for CNTF in response to renal injury, and that CNTF may play a role in chronic renal injury

Copper and gold cyclic (alkyl)(amino)carbene complexes with sub-microsecond photoemissions: Structure and substituent effects on redox and luminescent properties

Copper and gold halide and pseudo-halide complexes stabilized by methyl-, ethyl- and adamantyl-substituted cyclic (alkyl)(amino)¬carbene (CAAC) ligands are mostly linear monomers in the solid state, without aurophilic Au···Au interactions. (Et2L)CuCl shows the highest photoluminescence quantum yield (PLQY) in the series, 70%. The photoemissions of Me2L and Et2L copper halide complexes show S1 → S0 fluorescence on the ns time scale, in agreement with theory, as well as a minor long-lived emission. Monomeric (Me2L)CuNCS is a white emitter, while dimeric [(Et2L)Cu(µ-NCS)]2 shows intense yellow emission with a PLQY of 49%. The reaction of (AdL)MCl (M = Cu or Au) with phenols ArOH (Ar = Ph, 2,6-F2C6H3, 2,6-Me2C6H3, 3,5-But2C6H3, 2-But-5-MeC6H3, 2-pyridyl), thiophenol, or aromatic amines H2NAr' (Ar' = Ph, 3,5-(CF3)2C6H3, C6F5, 2-py) afforded the corresponding phenolato, thiophenolato and amido complexes. Whereas the emission wavelengths are only marginally affected by the ring substitution pattern, the PL intensities respond sensitively to the presence of substituents in ortho or meta position. In gold aryloxides PL is controlled by steric factors, with strong luminescence in compounds with Au-O-C-C torsion angles <50. Calculations confirm the dependence of oscillator strength on the torsion angle, as well as the inter-ligand charge transfer nature of the emission. The HOMO/LUMO energy levels were estimated based on first reduction and oxidation potentials

Predicting Stable Molecular Structures for (RNC)(2)(AuX)-X-I Complexes

Calculations have been performed at the MP2 and DFT levels for investigating the reasons for the difficulties in synthesizing bis(isocyanide)gold(I) halide complexes. Three-coordinated gold(I) complexes of the type (R3P)(2)(AuX)-X-I (1) can be synthesized, whereas the analogous isocyanide complexes (RNC)(2)(AuX)-X-I (2) are not experimentally known. The molecular structures of (R3P)(2)(AuX)-X-I (X = Cl, Br, and I) and (RNC)(2)(AuX)-X-I with X = halide, cyanide, nitrite, methylthiolate, and thiocyanate are compared and structural differences are discussed. Calculations of molecular properties elucidate which factors determine the strength of the gold-ligand interactions in (RNC)(2)(AuX)-X-I. The linear bonding mode of RNC favors a T-shaped geometry instead of the planar Y-shaped trigonal structure of (R3P)(2)(AuX)-X-I complexes that have been synthesized. An increased polarity of the Au-X bond in 2 leads to destabilization of the Y-shaped structure. Chalcogen-containing ligands or cyanide appear to be good X-ligand candidates for synthesis of (RNC)(2)(AuX)-X-I complexes.Peer reviewe

Differentiation-Dependent Secretion of Proangiogenic Factors by Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are a promising cell population for cell-based bone repair due to their proliferative potential, ability to differentiate into bone-forming osteoblasts, and their secretion of potent trophic factors that stimulate angiogenesis and neovascularization. To promote bone healing, autogenous or allogeneic MSCs are transplanted into bone defects after differentiation to varying degrees down the osteogenic lineage. However, the contribution of the stage of osteogenic differentiation upon angiogenic factor secretion is unclear. We hypothesized that the proangiogenic potential of MSCs was dependent upon their stage of osteogenic differentiation. After 7 days of culture, we observed the greatest osteogenic differentiation of MSCs when cells were cultured with dexamethasone (OM+). Conversely, VEGF protein secretion and upregulation of angiogenic genes were greatest in MSCs cultured in growth media (GM). Using conditioned media from MSCs in each culture condition, GM-conditioned media maximized proliferation and enhanced chemotactic migration and tubule formation of endothelial colony forming cells (ECFCs). The addition of a neutralizing VEGF165/121 antibody to conditioned media attenuated ECFC proliferation and chemotactic migration. ECFCs seeded on microcarrier beads and co-cultured with MSCs previously cultured in GM in a fibrin gel exhibited superior sprouting compared to MSCs previously cultured in OM+. These results confirm that MSCs induced farther down the osteogenic lineage possess reduced proangiogenic potential, thereby providing important findings for consideration when using MSCs for bone repair

Multi-Faceted Scientific Strategies Toward Better Solid-State Lighting of Phosphorescent OLEDs

This project has advanced solid-state lighting (SSL) by utilizing new phosphorescent systems for use in organic light-emitting diodes (OLEDs). The technical approach was two-fold: a) Targeted synthesis and screening of emitters designed to exhibit phosphorescence with maximized brightness in the solid state; and b) Construction and optimizing the performance of monochromatic and white OLEDs from the best new emitters to improve performance metrics versus the state of the art. The phosphorescent systems were screened candidates among a large variety of recentlysynthesized and newly-designed molecular and macromolecular metal-organic phosphors. The emitters and devices have been optimized to maximize light emission and color metrics, improve the long-term durability of emitters and devices, and reduce the manufacturing cost both by simplifying the process flow and by seeking less expensive device components than common ones. The project succeeded in all these goals upon comparison of the best materials and devices investigated vs. the state of the art of the technology

Genetic modification of smooth muscle cells to enhance the performance of tissue engineered vascular grafts

Development of small-diameter blood vessels using tissue engineering has been promising as a novel therapy for patients who require coronary artery bypass grafting but lack suitable donor tissue. However, the performance of tissue engineered vascular grafts (TEVGs) has been challenged by the lack of a complete endothelium and by poor mechanical properties which contribute to blood incompatibility and burst failure in vivo respectively. In this work, these challenges have been addressed by genetically modifying vascular smooth muscle cells (VSMCs) to produce factors that will promote endothelialization and improve mechanical properties. Genetic engineering of VSMCs was explored using different methods to obtain the optimal transfection system. Viral transduction of cells resulted in the highest efficiency and stability of expression. Neomycin selection of virally transduced SMCs resulted in a homogenous population with high expression levels. To promote endothelialization of TEVGs, VSMCs were virally-transduced to produce vascular endothelial growth factor (VEGF) which acts as a chemoattractant and mitogen of endothelial cells (ECs). The proliferation of ECs significantly increased after exposure to VEGF-transfected SMCs or their conditioned media. The chemotactic response of ECs to the VEGF-producing cells was explored by different in vitro models which demonstrated increased migration of ECs in response to VEGF-transfected cells on both tissue culture treated surfaces as well as collagen-coated surfaces. To improve mechanical properties, lysyl oxidase (LO) was utilized to enzymatically crosslink extracellular matrix (ECM) proteins, particularly collagen and elastin, to enhance the mechanical integrity of the ECM and thereby impart mechanical strength to the engineered tissue. Viral transduction of VSMCs resulted in increased LO expression using Northern and Western analysis. Increased LO activity was demonstrated using a fluorescent enzyme substrate assay, and as increased levels of desmosine, a product of LO crosslinking, in the ECM. The mechanical effects of altered crosslink densities within tissue engineered constructs were demonstrated in a VSMC-populated collagen gel model. VSMCs transfected with lysyl oxidase were seeded in collagen gels; the tensile strength and elastic modulus in these constructs increased by approximately three-fold compared to constructs seeded with mock transfected VSMCs. Compositional analysis of the ECM deposited by the transformed cells showed similar collagen and elastin levels, and cell proliferation rates were similar as well, thus attributing increased mechanical properties to ECM crosslinking

Gold, Silver, and Copper Nanoparticles Stabilized in Biocompatible Aqueous Media

Patent relating to gold, silver, and copper nanoparticles stabilized in biocompatible aqueous media