143 research outputs found
Catechol-O-methyltransferase: potential relationship to idiopathic hypertension
Catecholamine signaling pathways in the peripheral and central nervous systems (PNS, CNS, respectively) utilize catechol-O-methyltransferase (COMT) as a major regulatory enzyme responsible for deactivation of dopamine (DA), norepinephrine (NE) and epinephrine (E). Accordingly, homeostasis of COMT gene expression is hypothesized to be functionally linked to regulation of autonomic control of normotensive vascular events. Recently, we demonstrated that morphine administration in vitro resulted in decreased cellular concentrations of COMT-encoding mRNA levels, as compared to control values. In contrast, cells treated with E up regulated their COMT gene expression. In sum, these observations indicate a potential reciprocal linkage between end product inhibition of COMT gene expression by E and morphine. Interestingly, the observed effects of administered E on COMT gene expression suggest an enhancement of its own catabolism or, reciprocally, a stimulation morphine biosynthesis
New poly(ionic liquid)s based on poly(azomethine-pyridinium) salts and its use as heterogeneous catalysts for CO2 conversion
A fast and simple synthetic route towards a new family of poly(ionic liquids) based on aromatic crosslinked poly(azomethine-pyridinium) salts is described. These new polymers were prepared in one step from new diamine methyl pyridinium salts and isopthaldehyde, in 30 min under microwave irradiation. By this method, poly(azomethine-pyridinium) containing chloride (Cl), bis(trifluoromethylsulfonyl)imide (TFSI) and hexaflorophosphate (PF6) as counter-anions were synthetized. This new pyridinium poly(ionic liquid)s were obtained as insoluble powders showing high thermal stability. The poly(azomethine-pyridinium)s were tested as heterogeneous catalysts in the cycloaddition of CO2 to epichlorohydrin to obtain chloropropylene carbonate. The polymers containing chloride anion shows high content of catalytically active sites and the best performance of the series, with 100% selectivity towards the chloropropylene carbonate in a reaction without solvent at 3 bar of CO2, 100 °C and low catalyst loading (0.5 mol%).Spanish Government, MINECO (Projects MAT2014-52085-C2-2-P and MAT2017-82288-C2-2-P, MAT2017-83373-R
Dual redox-active porous polyimides as high performance and versatile electrode material for next-generation batteries
Energy storage will be a primordial actor of the ecological transition initiated in the energy and transport sectors. As such, innovative approaches to design high-performance electrode materials are crucial for the development of the next generation of batteries. Herein, a novel dual redox-active and porous polyimide network (MTA-MPT), based on mellitic trianhydride (MTA) and 3,7-diamino-N-methylphenothiazine (MPT) monomers, is proposed for applications in both high energy density lithium batteries and symmetric all-organic batteries. The MTA-MPT porous polyimide was synthesized using a novel environmentally-friendly hydrothermal polymerization method. Rooted in its dual redox proprieties, the MTA-MPT porous polyimide exhibits a high theoretical capacity making it a very attractive cathode material for high energy density battery applications. The cycling performance of this novel electrode material was assessed in both high energy density lithium batteries and light-weight symmetric all-organic batteries, displaying excellent rate capability and long-term cycling stability.N. Goujon acknowledges the funding from the European Union's Horizon 2020 framework programme under the Marie Sklodowska-Curie agreement No. 101028682. M. Lahnsteiner, H. M. Moura, D. A. Cerron-Infantes and M. M. Unterlass acknowledge funding through the Austrian Science Fund's (FWF) START programme under grant no. Y1037-N28. We thank Dr Jerpme Roeser and Prof. Arne Thomas (TU Berlin) for gas sorption measurements
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Conducting Polymer Scaffolds Based on Poly(3,4-ethylenedioxythiophene) and Xanthan Gum for Live-Cell Monitoring.
Conducting polymer scaffolds can promote cell growth by electrical stimulation, which is advantageous for some specific type of cells such as neurons, muscle, or cardiac cells. As an additional feature, the measure of their impedance has been demonstrated as a tool to monitor cell growth within the scaffold. In this work, we present innovative conducting polymer porous scaffolds based on poly(3,4-ethylenedioxythiophene) (PEDOT):xanthan gum instead of the well-known PEDOT:polystyrene sulfonate scaffolds. These novel scaffolds combine the conductivity of PEDOT and the mechanical support and biocompatibility provided by a polysaccharide, xanthan gum. For this purpose, first, the oxidative chemical polymerization of 3,4-ethylenedioxythiophene was carried out in the presence of polysaccharides leading to stable PEDOT:xanthan gum aqueous dispersions. Then, by a simple freeze-drying process, porous scaffolds were prepared from these dispersions. Our results indicated that the porosity of the scaffolds and mechanical properties are tuned by the solid content and formulation of the initial PEDOT:polysaccharide dispersion. Scaffolds showed interconnected pore structure with tunable sizes ranging between 10 and 150 μm and Young's moduli between 10 and 45 kPa. These scaffolds successfully support three-dimensional cell cultures of MDCK II eGFP and MDCK II LifeAct epithelial cells, achieving good cell attachment with very high degree of pore coverage. Interestingly, by measuring the impedance of the synthesized PEDOT scaffolds, the growth of the cells could be monitored
Mixed Conductive, Injectable, and Fluorescent Supramolecular Eutectogel Composites
Funding Information: This work was supported by Marie Sklodowska‐Curie Research and Innovation Staff Exchanges (RISE) under the grant agreement No 823989 “IONBIKE”. The financial support received from CONICET and ANPCyT (Argentina) is also gratefully acknowledged. M. C.‐G. thanks Emakiker Grant Program of POLYMAT. L. C. T. is grateful to Fundação para a Ciência e a Tecnologia (FCT/MCTES) in Portugal for her research contract under Scientific Employment Stimulus (2020.01555.CEECIND), and Associate Laboratory for Green Chemistry—LAQV, which is also financed by FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020). D. M. thanks “Ayuda RYC2021‐031668‐I financiada por MCIN/AEI/10.13039/501100011033 y por la Unión Europea NextGenerationEU/PRTR”. The authors thank the technical and human support provided by SGIker (UPV/EHU/ERDF, EU). Funding Information: This work was supported by Marie Sklodowska-Curie Research and Innovation Staff Exchanges (RISE) under the grant agreement No 823989 “IONBIKE”. The financial support received from CONICET and ANPCyT (Argentina) is also gratefully acknowledged. M. C.-G. thanks Emakiker Grant Program of POLYMAT. L. C. T. is grateful to Fundação para a Ciência e a Tecnologia (FCT/MCTES) in Portugal for her research contract under Scientific Employment Stimulus (2020.01555.CEECIND), and Associate Laboratory for Green Chemistry—LAQV, which is also financed by FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020). D. M. thanks “Ayuda RYC2021-031668-I financiada por MCIN/AEI/10.13039/501100011033 y por la Unión Europea NextGenerationEU/PRTR”. The authors thank the technical and human support provided by SGIker (UPV/EHU/ERDF, EU). Publisher Copyright: © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.Eutectogels are an emerging family of soft ionic materials alternative to ionic liquid gels and organogels, offering fresh perspectives for designing functional dynamic platforms in water-free environments. Herein, the first example of mixed ionic and electronic conducting supramolecular eutectogel composites is reported. A fluorescent glutamic acid-derived low-molecular-weight gelator (LMWG) was found to self-assemble into nanofibrillar networks in deep eutectic solvents (DES)/poly(3,4-ethylenedioxythiophene) (PEDOT): chondroitin sulfate dispersions. These dynamic materials displayed excellent injectability and self-healing properties, high ionic conductivity (up to 10−2 S cm−1), good biocompatibility, and fluorescence imaging ability. This set of features turns the mixed conducting supramolecular eutectogels into promising adaptive materials for bioimaging and electrostimulation applications.publishersversionpublishe
Inhibition of Dihydrotestosterone Synthesis in Prostate Cancer by Combined Frontdoor and Backdoor Pathway Blockade
Androgen deprivation therapy (ADT) is palliative and prostate cancer (CaP) recurs as lethal castration-recurrent/resistant CaP (CRPC). One mechanism that provides CaP resistance to ADT is primary backdoor androgen metabolism, which uses up to four 3α-oxidoreductases to convert 5α-androstane-3α,17β-diol (DIOL) to dihydrotestosterone (DHT). The goal was to determine whether inhibition of 3α-oxidoreductase activity decreased conversion of DIOL to DHT. Protein sequence analysis showed that the four 3α-oxidoreductases have identical catalytic amino acid residues. Mass spectrometry data showed combined treatment using catalytically inactive 3α-oxidoreductase mutants and the 5α-reductase inhibitor, dutasteride, decreased DHT levels in CaP cells better than dutasteride alone. Combined blockade of frontdoor and backdoor pathways of DHT synthesis provides a therapeutic strategy to inhibit CRPC development and growth
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