75 research outputs found

    Reprogramming Human Adult Fibroblasts into GABAergic Interneurons.

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    Direct reprogramming is an appealing strategy to generate neurons from a somatic cell by forced expression of transcription factors. The generated neurons can be used for both cell replacement strategies and disease modelling. Using this technique, previous studies have shown that Îł-aminobutyric acid (GABA) expressing interneurons can be generated from different cell sources, such as glia cells or fetal fibroblasts. Nevertheless, the generation of neurons from adult human fibroblasts, an easily accessible cell source to obtain patient-derived neurons, has proved to be challenging due to the intrinsic blockade of neuronal commitment. In this paper, we used an optimized protocol for adult skin fibroblast reprogramming based on RE1 Silencing Transcription Factor (REST) inhibition together with a combination of GABAergic fate determinants to convert human adult skin fibroblasts into GABAergic neurons. Our results show a successful conversion in 25 days with upregulation of neuronal gene and protein expression levels. Moreover, we identified specific gene combinations that converted fibroblasts into neurons of a GABAergic interneuronal fate. Despite the well-known difficulty in converting adult fibroblasts into functional neurons in vitro, we could detect functional maturation in the induced neurons. GABAergic interneurons have relevance for cognitive impairments and brain disorders, such as Alzheimer's and Parkinson's diseases, epilepsy, schizophrenia and autism spectrum disorders

    Joint health and treatment modalities in Nordic patients with moderate haemophilia A and B - The MoHem study

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    Introduction The prevalence of arthropathy in moderate haemophilia A (MHA) and B (MHB) is not well known. Aim We evaluated joint health in Nordic patients in relation to their treatment modality. Methods A cross-sectional, multicentre study covering MHA and MHB in Sweden, Finland and Norway. Arthropathy was evaluated by ultrasound (HEAD-US) and Haemophilia Joint Health Score (HJHS). Results We report on 145 patients: median age 28 years (IQR 13-52) and 61% MHA. Baseline factor VIII/factor IX activity (FVIII/FIX:C) was 2 IU/dL (median) (IQR 2-4): lower for MHB (2 IU/dL, IQR 1-2) than MHA (3 IU/dL, IQR 2-4) (P <.01). Eighty-five per cent of MHA and 73% MHB had a history of haemarthrosis (P = .07). Age at first joint bleed was lower for MHA (5 years [median], IQR 3-7) than MHB (7 years, IQR 5-12) (P = .01). Thirty-eight per cent received prophylaxis, started at median 10 years of age (IQR 4-24). Median joint bleeds and serious other bleeds during the last 12 months were both zero (IQR 0-1). Total HEAD-US captured 0/48 points (median) (IQR 0-2) and HJHS 4/120 points (IQR 1-10) with strong correlation between them (r = .72). FVIII/FIX:CPeer reviewe

    Att motivera förÀndring

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    FörÀndringar mÄste vara vÀl motiverade och förankrade hos bÄde elever och lÀrare. De mÄste vara anpassade till skolans mÄl och den enskilde studentens behov. I denna rapport presenteras ett antal förslag pÄ lösningar till nÄgra av de problem som kan uppstÄ dÄ man försöker införa nya pedagogiska metoder samt motivationens betydelse för det slutgiltiga resultatet

    Direct Reprogramming of Human Fetal- and Stem Cell-Derived Glial Progenitor Cells into Midbrain Dopaminergic Neurons

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    Human glial progenitor cells (hGPCs) are promising cellular substrates to explore for the in situ production of new neurons for brain repair. Proof of concept for direct neuronal reprogramming of glial progenitors has been obtained in mouse models in vivo, but conversion using human cells has not yet been demonstrated. Such studies have been difficult to perform since hGPCs are born late during human fetal development, with limited accessibility for in vitro culture. In this study, we show proof of concept of hGPC conversion using fetal cells and also establish a renewable and reproducible stem cell-based hGPC system for direct neural conversion in vitro. Using this system, we have identified optimal combinations of fate determinants for the efficient dopaminergic (DA) conversion of hGPCs, thereby yielding a therapeutically relevant cell type that selectively degenerates in Parkinson's disease. The induced DA neurons show a progressive, subtype-specific phenotypic maturation and acquire functional electrophysiological properties indicative of DA phenotype

    Markers of neutrophil activation and neutrophil extracellular traps in diagnosing patients with acute venous thromboembolism: A feasibility study based on two VTE cohorts

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    Background: Venous thromboembolism (VTE) diagnosis would greatly benefit from the identification of novel biomarkers to complement D-dimer, a marker limited by low specificity. Neutrophil extracellular traps (NETs) have been shown to promote thrombosis and could hypothetically be used for diagnosis of acute VTE. Objectives: To assess the levels of specific markers of neutrophil activation and NETs and compare their diagnostic accuracy to D-dimer. Methods: We measured plasma levels of neutrophil activation marker neutrophil elastase (NE), the NET marker nucleosomal citrullinated histone H3 (H3Cit-DNA) and cell-free DNA in patients (n = 294) with suspected VTE (pulmonary embolism and deep vein thrombosis) as well as healthy controls (n = 30). A total of 112 VTE positive and 182 VTE negative patients from two prospective cohort studies were included. Results: Higher levels of H3Cit-DNA and NE, but not cell-free DNA, were associated with VTE. Area under receiver operating curves (AUC) were 0.90 and 0.93 for D-dimer, 0.65 and 0.68 for NE and 0.60 and 0.67 for H3Cit-DNA in the respective cohorts. Adding NE and H3Cit-DNA to a D-dimer based risk model did not improve AUC. Conclusions: Our study demonstrates the presence of neutrophil activation and NET formation in VTE using specific markers. However, the addition of NE or H3Cit-DNA to D-dimer did not improve the discrimination compared to D-dimer alone. This study provides information on the feasibility of using markers of NETs as diagnostic tools in acute VTE. Based on our findings, we believe the potential of these markers are limited in this setting

    Astrocyte dysfunction and neuronal network hyperactivity in a CRISPR engineered pluripotent stem cell model of frontotemporal dementia

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    Frontotemporal dementia (FTD) is the second most prevalent type of early-onset dementia and up to 40% of cases are familial forms. One of the genes mutated in patients is CHMP2B, which encodes a protein found in a complex important for maturation of late endosomes, an essential process for recycling membrane proteins through the endolysosomal system. Here, we have generated a CHMP2B-mutated human embryonic stem cell line using genome editing with the purpose to create a human in vitro FTD disease model. To date, most studies have focused on neuronal alterations; however, we present a new co-culture system in which neurons and astrocytes are independently generated from human embryonic stem cells and combined in co-cultures. With this approach, we have identified alterations in the endolysosomal system of FTD astrocytes, a higher capacity of astrocytes to uptake and respond to glutamate, and a neuronal network hyperactivity as well as excessive synchronization. Overall, our data indicates that astrocyte alterations precede neuronal impairments and could potentially trigger neuronal network changes, indicating the important and specific role of astrocytes in disease development

    DNA damage by lipid peroxidation products: implications in cancer, inflammation and autoimmunity

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    Oxidative stress and lipid peroxidation (LPO) induced by inflammation, excess metal storage and excess caloric intake cause generalized DNA damage, producing genotoxic and mutagenic effects. The consequent deregulation of cell homeostasis is implicated in the pathogenesis of a number of malignancies and degenerative diseases. Reactive aldehydes produced by LPO, such as malondialdehyde, acrolein, crotonaldehyde and 4-hydroxy-2-nonenal, react with DNA bases, generating promutagenic exocyclic DNA adducts, which likely contribute to the mutagenic and carcinogenic effects associated with oxidative stress-induced LPO. However, reactive aldehydes, when added to tumor cells, can exert an anticancerous effect. They act, analogously to other chemotherapeutic drugs, by forming DNA adducts and, in this way, they drive the tumor cells toward apoptosis. The aldehyde-DNA adducts, which can be observed during inflammation, play an important role by inducing epigenetic changes which, in turn, can modulate the inflammatory process. The pathogenic role of the adducts formed by the products of LPO with biological macromolecules in the breaking of immunological tolerance to self antigens and in the development of autoimmunity has been supported by a wealth of evidence. The instrumental role of the adducts of reactive LPO products with self protein antigens in the sensitization of autoreactive cells to the respective unmodified proteins and in the intermolecular spreading of the autoimmune responses to aldehyde-modified and native DNA is well documented. In contrast, further investigation is required in order to establish whether the formation of adducts of LPO products with DNA might incite substantial immune responsivity and might be instrumental for the spreading of the immunological responses from aldehyde-modified DNA to native DNA and similarly modified, unmodified and/or structurally analogous self protein antigens, thus leading to autoimmunity

    Tyre Models for Online Identification in ADAS Applications

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    Knowledge of the tire-road friction condition is an important key for driver safety and vehicle stability systems during ice and snow road. In particular, friction information can be used to enhance the performance of Advanced Driver-Assistance Systems (ADAS) applications providing real-time forces condition. The paper deals with a method for real-time identification of tyre/road friction condition using both Pacejka model and steady state form of distributed LuGre to obtain the friction based on recursive nonlinear optimization of the curve fitting errors. Finally, the effectiveness of the method is confirmed by real-time simulations in ice and snow conditions

    Prepositioning of driving simulator motion systems

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    Motion base driving simulators have limited space in which to recreate the motions of the simulated road vehicle. Conventional motion cueing algorithms strive to centre the cabin in the simulator motion envelope to accommodate accelerations in a worst case scenario while respecting the physical boundaries. Using information about the road ahead one can preposition the cabin to an off-centre point, virtually increasing the available space so that larger motions are made possible. The prepositioning algorithm presented here was developed as an addition to a classical motion cueing algorithm and makes use of road data and vehicle speed to adjust the simulator displacement. Simulations show that the amount of acceleration presented by an x, y-sled system can, with prepositioning, be increased by up to 25% in longitudinal and 53% in lateral direction for an example road. A comparative study including 12 test subjects indicates that the perceived realism is rated higher with prepositioning

    L'ECO DELLE PIETRE: HISTORY, MODELING, AND GPR AS TOOLS IN RECONSTRUCTING THE CHOIR SCREEN AT STA. CHIARA IN NAPLES

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    This essay describes the use of Ground-Penetrating Radar (GPR) to establish the location and dimensions of the destroyed choir screen at the church of Sta. Chiara in Naples. On the basis of this new evidence, inserted within a laser scan of the church that provides its exact dimensions, the authors have been able to reconstruct a hypothetical model of the screen's original appearance. The model, if correct, suggests that the choir screen not only contained altars to Saints Francis and Claire (now present in the flanking side chapels), but also that it supported an upper gallery that connected the wide tribunes on either side of the nave. It is hoped that this hypothetical model will stimulate new research on the decor, liturgy, and ceremonial functions of this important Neapolitan church
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