131,273 research outputs found
Small ribosomal subunits associate with nuclear myosin and actin in transit to the nuclear pores.
No full textWe have followed at high resolution theribosomal protein S6 entering the nucleus of HeLacells, stopping in some (not all) interchromatin granulesclusters and reaching, via Cajal bodies, the nucleolus.There, S6 is assembled with other proteins andrRNA into small ribosomal subunit (SSU), released inthe nucleoplasm, and exported through the nuclearpores. We show for the first time the spatial associationof nuclear myosin I (NMI) and actin with the SSUalready at the nucleolar periphery to the nuclear pore.A blockade of NMI or actin induces an upstreamaccumulation of the S6 protein en route to the nucleolus,and a temperature lower than normal influencesRNA export. Our data strongly suggest a functionalrelationship of SSU with NMI and actin. In our hypothesis,an active, myosin-driven movement of the smallribosomal subunit can be responsible for the exportof 10% of SSUs. This hypothesis is supported byultrastructural, immunofluorescence, and biochemicalanalyses. The currently accepted model for the subunitrelease suggests a diffusive, temperature-independentmechanism. However, the advantage of the doublemechanism would assure that the movement of a partof the subunits could be modulated, increased, ordecreased according to the needs of the cell at a specificmoment in the cell cycle.—Cisterna, B., Necchi, D.,Prosperi, E., Biggiogera, M. Small ribosomal subunitsassociate with nuclear myosin and actin in transit to thenuclear pores
Proyecto de reforma en almacén situado en Calle Cisterna del Pozo de Puzol para D. Vicente Almenara Beltrán, 1956
No full textContiene : Memorias ; Plantas de entramados ; Emplazamientos ; Secciones ; Planos de distribución ; Planos de estructura ; Alzados ; Fachadas . Documentación original y adicional disponible en Archivo-CIAProyecto de reforma de elevación de una planta en Almacén situado en la Calle Cisterna del Pozo de Puzol para Don Vicente Almenara Beltrán, 1956Rieta Sister, J. (1957). Proyecto de reforma en almacén situado en Calle Cisterna del Pozo de Puzol para D. Vicente Almenara Beltrán, 1956. Universitat Politècnica de València. Escuela Técnica Superior de Arquitectura - Escola Tècnica Superior d'Arquitectura. https://riunet.upv.es/handle/10251/74841AR
Interaction of GFP-SCs with myelin and astrocytes after delivery in the cisterna magna or the spinal cord parenchyma.
No full text<p>Combined detection of MOG, GFAP and GFP on cryostat sections showed that GFP-SCs grafted in the cisterna magna (A, D) or the spinal cord (B,C, E, F) are found in demyelinated lesions (delineated by dashed lines) detected by MOG immunostaining (red) both after 7 days (B) and 21 days (A, C) after delivery. GFAP+ astrocytes (blue) interact with GFP-labeled SCs in the cisterna magna (D) and the spinal cord (E, F); 7 days (E) or 21 days (F) after spinal cord graft or 21 days after cisterna magna graft (D).</p
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Access to cerebrospinal fluid in piglets via the cisterna magna: optimization and description of the technique.
No full textThe collection of cerebrospinal fluid is necessary in order to determine its composition. It can then be used to
diagnose various diseases. The aim of the study was to develop and optimize a technique for performing safe
centesis for the collection of cerebrospinal fluid in piglets and its injection through the cisterna magna. The
study was divided into three phases: (1) anatomical study of cadavers, (2) in vivo application of the technique
and (3) observation of recovery time. The proposed technique resulted in a safe puncture of the cisterna
magna. The authors identified and confirmed the correspondence of the crista occipitalis and the wings of the
atlas with the external landmarks on the cadaver by means of direct radiological visualization. The punctures
were performed successfully at the first attempt in 11 out of 12 anaesthetized piglets. The technique herein
described provides a reproducible safe and easy route for approaching the cisterna magna for cerebrospinal
fluid collection, drug administration and gene delivery
DELIVERY OF D-ALA2-D-LEU5-ENKEPHALIN TO B50 NEURONAL CELLS BY MEANS OF CHITOSAN NANOPARTICLES
No full textAccess to the central nervous system (CNS) is regulated by the blood brain barrier (BBB). The BBB providesstringent control on the extracellular neuronal environment thereby supporting proper function;unfortunately, it acts at the same time as a substantial limit to drug delivery to the CNS.Chitosan nanoparticles (ChiNPs) are biocompatible drug carriers able to pass biological barriers and the cellmembrane: in particular, ChiNPs can cross the blood brain barrier, thus representing a promising deliverysystem to CNS. In this work we tested the ability of ChiNPs to deliver the syntethic opiod DADLE (D-Ala2-DLeu5-enkephalin) to cultured B50 rat neuronal cells. DADLE is able to induce reversible hypometabolizingeffects, representing a promising agent for neuroprotection, preservation of explanted organs and antitumourtreatments. Since DADLE has a short plasmatic half-life and is unable to cross the blood brainbarrier, its encapsulation in ChiNPs would allow the blood brain barrier to be crossed and the peptide beprotected from enzymatic degradation.We demonstrate by immunoelectron microscopy that ChiNPs are efficient opioid carriers to neuronal cells,protecting incorporated molecules from enzymatic degradation and prolonging their intracellular effects.DADLE is released from ChiNPs inside the call for up to 48h. It binds to the nuclear transcription/splicingsites, decreasing transcriptional activity without damaging cell organelles.In conclusion, these results pave the way to in vivo experiments aimed at elucidating whether DADLEloadedchitosan NPs may efficiently deliver the opioid to the central nervous system
Satellite cells in skeletal muscle of the hibernating dormouse, a natural model of quiescence and re-activation: focus on the cell nucleus
No full textSatellite cells (SCs) participate in skeletal muscle plasticity/regeneration. Activation of SCs implies that nuclear changes underpin a new functional status. In hibernating mammals, periods of reduced metabolic activity alternate with arousals and resumption of bodily functions, thereby leading to repeated cell deactivation and reactivation. In hibernation, muscle fibers are preserved despite long periods of immobilization. The structural and functional characteristics of SC nuclei during hibernation have not been investigated yet. Using ultrastructural and immunocytochemical analysis, we found that the SCs of the hibernating edible dormouse, Glis glis, did not show apoptosis or necrosis. Moreover, their nuclei were typical of quiescent cells, showing similar amounts and distributions of heterochromatin, pre-mRNA transcription and processing factors, as well as paired box protein 7 (Pax7) and the myogenic differentiation transcription factor D (MyoD), as in euthermia. However, the finding of accumulated perichromatin granules (i.e., sites of storage/transport of spliced pre-mRNA) in SC nuclei of hibernating dormice suggested slowing down of the nucleus-to-cytoplasm transport. We conclude that during hibernation, SC nuclei maintain similar transcription and splicing activity as in euthermia, indicating an unmodified status during immobilization and hypometabolism. Skeletal muscle preservation during hibernation is presumably not due to SC activation, but rather to the maintenance of some functional activity in myofibers that is able to counteract muscle wasting
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