100 research outputs found

    Biciliated ependymal cell proliferation contributes to spinal cord growth

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    Two neurogenic regions have been described in the adult brain, the lateral ventricle subventricular zone and the dentate gyrus subgranular zone. It has been suggested that neural stem cells also line the central canal of the adult spinal cord. Using transmission and scanning electron microscopy and immunostaining, we describe here the organization and cell types of the central canal epithelium in adult mice. The identity of dividing cells was determined by three-dimensional ultrastructural reconstructions of [3H]thymidine-labeled cells and confocal analysis of bromodeoxyuridine labeling. The most common cell type lining the central canal had two long motile (9+2) cilia and was vimentin+, CD24+, FoxJ1+, Sox2+ and CD133+, but nestin- and glial fibrillary acidic protein (GFAP)-. These biciliated ependymal cells of the central canal (Ecc) resembled E2 cells of the lateral ventricles, but their basal bodies were different from that of E2 or E1 cells. Interestingly, we frequently found Ecc cells with two nuclei and four cilia, suggesting they are formed by incomplete cytokinesis or cell fusion. GFAP+ astrocytes with a single cilium and an orthogonally oriented centriole were also observed. The majority of dividing cells corresponded to biciliated Ecc cells. Central canal proliferation was most common during the active period of spinal cord growth. Pairs of labeled Ecc cells were observed within the central canal in adult mice 2.5 weeks post-labeling. Our work suggests that the vast majority of postnatal dividing cells in the central canal are Ecc cells and their proliferation is associated with the growth of the spinal cord

    Distribution of GABAergic Interneurons and Dopaminergic Cells in the Functional Territories of the Human Striatum

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    BACKGROUND: The afferent projections of the striatum (caudate nucleus and putamen) are segregated in three territories: associative, sensorimotor and limbic. Striatal interneurons are in part responsible for the integration of these different types of information. Among them, GABAergic interneurons are the most abundant, and can be sorted in three populations according to their content in the calcium binding proteins calretinin (CR), parvalbumin (PV) and calbindin (CB). Conversely, striatal dopaminergic cells (whose role as interneurons is still unclear) are scarce. This study aims to analyze the interneuron distribution in the striatal functional territories, as well as their organization regarding to the striosomal compartment. METHODOLOGY/PRINCIPAL FINDINGS: We used immunohistochemical methods to visualize CR, PV, CB and tyrosine hydroxylase (TH) positive striatal neurons. The interneuronal distribution was assessed by stereological methods applied to every striatal functional territory. Considering the four cell groups altogether, their density was higher in the associative (2120±91 cells/mm(3)) than in the sensorimotor (959±47 cells/mm(3)) or limbic (633±119 cells/mm(3)) territories. CB- and TH-immunoreactive(-ir) cells were distributed rather homogeneously in the three striatal territories. However, the density of CR and PV interneurons were more abundant in the associative and sensorimotor striatum, respectively. Regarding to their compartmental organization, CR-ir interneurons were frequently found in the border between compartments in the associative and sensorimotor territories, and CB-ir interneurons abounded at the striosome/matrix border in the sensorimotor domain. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that the architecture of the human striatum in terms of its interneuron composition varies in its three functional territories. Furthermore, our data highlight the importance of CR-ir striatal interneurons in the integration of associative information, and the selective role of PV-ir interneurons in the motor territory. On the other hand, the low density of dopaminergic cells casts doubts about their role in the normal human striatum

    Cholinergic Interneurons Are Differentially Distributed in the Human Striatum

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    BACKGROUND: The striatum (caudate nucleus, CN, and putamen, Put) is a group of subcortical nuclei involved in planning and executing voluntary movements as well as in cognitive processes. Its neuronal composition includes projection neurons, which connect the striatum with other structures, and interneurons, whose main roles are maintaining the striatal organization and the regulation of the projection neurons. The unique electrophysiological and functional properties of the cholinergic interneurons give them a crucial modulating function on the overall striatal response. METHODOLOGY/PRINCIPLE FINDINGS: This study was carried out using stereological methods to examine the volume and density (cells/mm(3)) of these interneurons, as visualized by choline acetyltransferase (ChAT) immunoreactivity, in the following territories of the CN and Put of nine normal human brains: 1) precommissural head; 2) postcommissural head; 3) body; 4) gyrus and 5) tail of the CN; 6) precommissural and 7) postcommissural Put. The distribution of ChAT interneurons was analyzed with respect to the topographical, functional and chemical territories of the dorsal striatum. The CN was more densely populated by cholinergic neurons than the Put, and their density increased along the anteroposterior axis of the striatum with the CN body having the highest neuronal density. The associative territory of the dorsal striatum was by far the most densely populated. The striosomes of the CN precommissural head and the postcommissural Put contained the greatest number of ChAT-ir interneurons. The intrastriosomal ChAT-ir neurons were abundant on the periphery of the striosomes throughout the striatum. CONCLUSIONS/SIGNIFICANCE: All these data reveal that cholinergic interneurons are differentially distributed in the distinct topographical and functional territories of the human dorsal striatum, as well as in its chemical compartments. This heterogeneity may indicate that the posterior aspects of the CN require a special integration of information by interneurons. Interestingly, these striatal regions have been very much left out in functional studies

    Exploring the interpersonal-, organization-, and system-level factors that influence the implementation and use of an innovation-synoptic reporting-in cancer care

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    <p>Abstract</p> <p>Background</p> <p>The dominant method of reporting findings from diagnostic and surgical procedures is the narrative report. In cancer care, this report inconsistently provides the information required to understand the cancer and make informed patient care decisions. Another method of reporting, the synoptic report, captures specific data items in a structured manner and contains only items critical for patient care. Research demonstrates that synoptic reports vastly improve the quality of reporting. However, synoptic reporting represents a complex innovation in cancer care, with implementation and use requiring fundamental shifts in physician behaviour and practice, and support from the organization and larger system. The objective of this study is to examine the key interpersonal, organizational, and system-level factors that influence the implementation and use of synoptic reporting in cancer care.</p> <p>Methods</p> <p>This study involves three initiatives in Nova Scotia, Canada, that have implemented synoptic reporting within their departments/programs. Case study methodology will be used to study these initiatives (the cases) in-depth, explore which factors were barriers or facilitators of implementation and use, examine relationships amongst factors, and uncover which factors appear to be similar and distinct across cases. The cases were selected as they converge and differ with respect to factors that are likely to influence the implementation and use of an innovation in practice. Data will be collected through in-depth interviews, document analysis, observation of training sessions, and examination/use of the synoptic reporting tools. An audit will be performed to determine/quantify use. Analysis will involve production of a case record/history for each case, in-depth analysis of each case, and cross-case analysis, where findings will be compared and contrasted across cases to develop theoretically informed, generalisable knowledge that can be applied to other settings/contexts. Ethical approval was granted for this study.</p> <p>Discussion</p> <p>This study will contribute to our knowledge base on the multi-level factors, and the relationships amongst factors in specific contexts, that influence implementation and use of innovations such as synoptic reporting in healthcare. Such knowledge is critical to improving our understanding of implementation processes in clinical settings, and to helping researchers, clinicians, and managers/administrators develop and implement ways to more effectively integrate innovations into routine clinical care.</p

    Macroeconomic determinants of long-term government yields : a study of American and Norwegian yields using an ECM approach

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    This thesis examines the macroeconomic determinants of 10-year government bond yields in Norway and the US. We use Johansen cointegration testing and a VECM framework to identify long-run relationships between non-stationary variables. These relationships are further used in a more flexible ECM framework. We find that US rates prior to 2007 had a stable long-run relationship with the US policy rate, 5-year inflation expectations and the current account. Furthermore, we find short-run effects from the policy rate, inflation expectations, VIX (expected volatility in financial markets) and PMI (business cycles), as well as some evidence of an effect of government debt. We find that Norwegian rates over the entire period have a stable long-run relationship with the German 10-year rate and the Norwegian policy rate. We find short-run effects in the pre- 2007 period for the policy rate, German 10-year rate, and the VIX index. We find large changes in the post-2007 period for both countries. Neither rate react to any significant degree to deviations from long-run relationships, and the US long-run relationship breaks completely down. For both countries, most of the estimated short-run effects weaken, or disappear. In this period, the effect of government debt supply is clearer and we also find effects from increases in central bank reserves indicating that QE has had a large impact on long-term rates. In Norway, we only find a significant short-run effect from the German 10-year rate. Overall, we find that the period since 2007 represent a large change in determination of longterm rates compared to the 16 years prior to that period. Even though there have been large changes, our models are still able to predict movements in the rates in recent years relatively well, with some exceptions which are discussed.nhhma

    Relasjonens betydning for ungdommens mulighet til brukermedvirkning i barnevernet – en litteraturgjennomgang

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    Denne litteraturgjennomgangen har som formål å forsøke å besvare problemstillingen om hvorfor relasjon mellom ansatte og ungdom i barnevernet kan ha betydning for å oppnå brukermedvirkning. For å besvare denne problemstillingen drøftes fire fagfellevurderte forskningsartikler opp mot relevant teori. Det undersøkes hva ungdommen selv betegner som avgjørende faktorer for at relasjonen skal fungere på best mulig måte og hva som kreves av den ansatte for at relasjonen skal oppleves som positiv. Det legges også frem eksempler hvor ungdom beskriver hvilke utfordringer de har møtt på når det gjelder brukermedvirkning i barnevernet, men også erfaringer som er gode og mer krevende når det kommer til relasjonen til den ansatte. Funnene i de ulike artiklene har vært varierende og det presenteres ungdom som sitter på ulike erfaringer når det kommer til brukermedvirkning. Likevel ser en gjennomgående i artiklene at relasjonen er en faktor som ungdommen trekker frem som avgjørende for deltakelse og som viser seg å ha stor innvirkning på hvordan ungdom opplever brukermedvirkning i barnevernet. Avslutningsvis trekkes det konklusjon på problemstillingne og det presenteres forslag til videre forskning som har grunnlag i undringer som er forekommet underveis i arbeidet med oppgaven

    Stakeholder Analysis: A Useful Tool for Biobank Planning

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    Stakeholders are individuals, groups, or organizations that are affected by or can affect a particular action undertaken by others. Biobanks relate to a number of donors, researchers, research institutions, regulatory bodies, funders, and others. These stakeholders can potentially have a strong influence upon the organization and operation of a biobank. A sound strategy for stakeholder engagement is considered essential in project management and organization theory. In this article, we review relevant stakeholder theory and demonstrate how a stakeholder analysis was undertaken in the early stage of a planned research biobank at a public hospital in Norway
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