4,284 research outputs found

    Supramolecular aggregates containing lipophilic Gd(III) complexes as contrast agents in MRI

    Get PDF
    Magnetic resonance imaging (MRI) contrast agents based on paramagnetic gadolinium complexes are widely used in biomedical research and diagnosis. Their application is intended to improve efficacy of MRI providing physiological information along with the impressive anatomical detail already obtained by images without contrast. The classical gadolinium complexes currently used for MRI contrast enhancement are all lowmolecularweightcompounds that rapidly equilibrate between the intra and extravascular spaces after intravenous administration. In order to obtain gadolinium-based agents with different pharmacokinetic properties, supramolecular aggregates such as micelles and liposomes have been recently proposed. Micelles and liposomes, obtained by the aggregation of lipophilic gadolinium complexes are here described, with the aim to correlate their structural and relaxometric properties.We report on the state of the art in the development of supramolecular aggregates obtained by self-assembly of lipophilic gadolinium complexes and aggregates in which lipophilic gadolinium complexes are assembled with surfactants. Moreover aggregates derivatized with bioactive molecules, such as peptides and antibodies, acting as target selective MRI contrast agents are described

    Zur Frage der Bardepot-Pflicht

    Full text link

    RNomics: a computational search for box C/D snoRNA genes in the D. melanogaster genome.

    Get PDF
    Motivation: In eukaryotes, the family of non-coding RNA genes includes a number of genes encoding small nucleolar RNAs (mainly C/D and H/ACA snoRNAs), which act as guides in the maturation or post-transcriptional modifications of target RNA molecules. Since in Drosophila melanogaster (Dm) only few examples of snoRNAs have been identified so far by cDNA libraries screening, integration of the molecular data with in silico identification of these types of genes could throw light on their organization in the Dm genome. Results: We have performed a computational screening of the Dm genome for C/D snoRNA genes, followed by experimental validation of the putative candidates. Few of the 26 confirmed snoRNAs had been recognized by cDNA library analysis. Organization of the Dm genome was also found to be more variegated than previously suspected, with snoRNA genes nested in both the introns and exons of protein-coding genes. This finding suggests that the presence of additional mechanisms of snoRNA biogenesis based on the alternative production of overlapping mRNA/snoRNA molecules. Availability: Additional information is available at http://www. bioinformatica.unito.it/bioinformatics/snoRNA

    Peptide-based targeting strategies for simultaneous imaging and therapy with nanovectors

    Get PDF
    Over recent years, multifunctional compounds that combine diagnostic and therapeutic modalities using one unified material have been developed and designated as theranostics. These compounds provide the chance to develop individually designed therapies against various diseases to accomplish personalized medicine. In this review, theranostic agents based on nanovectors (liposomes, naposomes, micelles, polymeric micelles and micelles built around a solid core) externally modified with targeting peptides able to simultaneously carry a drug and a contrast agent are described, demonstrating that peptide-modified nanovectors can selectively carry a drug to target cells with an imaging probe co-incorporated into the nanovector to monitor therapy

    Liposomes derivatized with tetrabranched Neurotensin peptide via click chemistry reactions

    Get PDF
    Liposomes decorated with Neurotensin tetramers are obtained by using a post-liposomal derivatization method in which a click-chemistry reaction between liposomes containing azido functions on the external surface and branched neurotensin peptides modified for the presence of a C-C triple-bond is performed

    Naposomes: a new class of peptide-derivatized, target-selectivemultimodal nanoparticles for imaging and therapeutic applications

    Get PDF
    Modified supramolecular aggregates for selective delivery of contrast agents and/or drugs are examined with a focus on a new class of peptide-derivatized nanoparticles: naposomes. These nanoparticles are based on the co‑aggregation of two different amphiphilic monomers that give aggregates of different shapes and sizes (micelles, vesicles and liposomes) with diameters ranging between 10 and 300 nm. Structural properties and in vitro and in vivo behaviors are discussed. For the high relaxitivity values (12–19 mM-1s-1) and to detect for the presence of a surface exposed peptide, the new peptide-derived supramolecular aggregates are very promising candidates as targetselective MRI contrast agents. The efficiency of surface-exposed peptides in homing these nanovectors to a specific target introduces promising new opportunities for the development of diagnostic and therapeutic agents with high specificity toward the biological target and reduced toxic side effects on nontarget organs

    Nanostructures by Self-assembling Peptide Amphiphile as Potential Selective Drug Carriers

    Get PDF
    The self-assembling behaviour, at physiological pH, of the amphiphile peptide (C18)(2)L5CCK8 in nanostructures is reported. Stable aggregates presenting a critical micellar concentration of 2 X 10(-6) mol kg(-1), and characterized by water exposed CCK8 peptide in P-sheet conformation, are obtained. Small angle neutron scattering experiments are indicative for a 3D structure with dimensions >= 100 nm. AFM images confirm the presence of nanostructures. Fluorescence experiments indicating the sequestration of pyrene, chosen as drug model, and the anticancer Doxorubicin within the nanostructures are reported

    Connaissance des associations

    Get PDF
    A la suite de la deuxième Conférence de la vie associative (décembre 2009), un groupe de travail du Cnis, "Connaissance des associations", a été constitué, pour faire le point sur l'état actuel du dispositif de suivi statistique du secteur associatif et proposer des voies d'amélioration. le groupe a pu constater les notables avancées réalisées récemment par le système statistique public, mais aussi à l'extérieur de celui-ci. Il a aussi pu mesurer l'ampleur de ce qui reste à faire pour rendre compte à la fois de l'activité économique de ces organisations et de leur contribution à plusieurs dimensions du bien-être de la société. A ce titre, le rapport formule plusieurs recommandations. Il convient ainsi, principalement de : - Mettre en place une enquête nationale périodique sur les associations. - Poursuivre et compléter l'élaboration du Répertoire National des Associations (RNA) et améliorer la qualité du Répertoire Sirène dans le champ des associations, en l'appariant notamment avec le RNA. - Améliorer et rendre cohérentes les données sur l'emploi associatif - Créer un dispositif pérenne d'observation du bénévolat. - Compléter la connaissance des ressources des associations - Réaliser un compte satellite complet des institutions sans but lucratif comparable internationalement - Disposer d'outils adaptés à l'évaluation d'indicateurs sectoriels de l'"utilité sociale" des associations. Au-delà, le rapport souligne la nécessité de créer, de préférence au sein du système statistique public, une unité dédiée au suivi statistique des associations, condition sans laquelle la plupart de ces mesures spécifiques risquent de pas être réalisées jusqu'au bout.associations; institutions sans but lucratif; répertoires; nomenclatures; emploi associatif; bénévolat; ressources; utilité sociale

    Actuators based on intrinsic conductive polymers/carbon nanoparticles nanocompositesElectroactive Polymer Actuators and Devices (EAPAD) 2013

    Get PDF
    New polyaniline (PANi) synthesis was performed starting from non-toxic N-phenil-p-phenylenediamine (aniline dimer) using reverse addition of monomer to oxidizing agent, the synthesis allows to produce highly soluble PANi. Several types of doped PANi were prepared to be used on electromechanical active actuators. Different techniques were used to include carbon nanoparticles such as carbon nanotubes and graphene. Bimorph solid state ionic actuators were prepared with these novel nanocomposites using a variety of supporting polymer
    corecore