4,284 research outputs found
Supramolecular aggregates containing lipophilic Gd(III) complexes as contrast agents in MRI
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
RNomics: a computational search for box C/D snoRNA genes in the D. melanogaster genome.
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
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
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
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
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
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
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
Peptide-Based Drug Delivery Systems: Future Challenges, Perspectives, and Opportunities in Nanomedicine
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