120 research outputs found

    Steuerung humaner testikulärer peritubulärer Zellen durch TNFalpha und 15-deoxy-Prostaglandin J2

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    Corporate Social Responsibility in Family Firms: Status and Future Directions of a Research Field

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    This systematic literature review contributes to the increasing interest regarding corporate social responsibility (CSR) in family firms—a research field that has developed considerably in the last few years. It now provides the opportunity to take a holistic view on the relationship dynamics—i.e., drivers, activities, outcomes, and contextual influences—of family firms with CSR, thus enabling a more coherent organization of current research and a sounder understanding of the phenomenon. To conceptualize the research field, we analyzed 122 peer-reviewed articles published in highly ranked journals identifying the main issues examined. The results clearly show a lack of research regarding CSR outcomes in family firms. Although considered increasingly crucial in family firm research, a study investigating family outcomes (e.g., family community status, family emotional well-being), as opposed to firm outcomes, is missing. This literature review outlines the current state of research and contributes to the actual debate on CSR in family firms by discussing how family firms can use CSR activities as strategic management tools. Moreover, our analysis shows a black box indicating how CSR links different antecedents and outcomes. The black box is significant since firms generally need to know where to allocate their scarce resources to generate the best outcomes. We identify nine research questions based on these findings, which we hope will inspire future research

    Traction force microscopy with optimized regularization and automated Bayesian parameter selection for comparing cells

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    Adherent cells exert traction forces on to their environment, which allows them to migrate, to maintain tissue integrity, and to form complex multicellular structures. This traction can be measured in a perturbation-free manner with traction force microscopy (TFM). In TFM, traction is usually calculated via the solution of a linear system, which is complicated by undersampled input data, acquisition noise, and large condition numbers for some methods. Therefore, standard TFM algorithms either employ data filtering or regularization. However, these approaches require a manual selection of filter- or regularization parameters and consequently exhibit a substantial degree of subjectiveness. This shortcoming is particularly serious when cells in different conditions are to be compared because optimal noise suppression needs to be adapted for every situation, which invariably results in systematic errors. Here, we systematically test the performance of new methods from computer vision and Bayesian inference for solving the inverse problem in TFM. We compare two classical schemes, L1- and L2-regularization, with three previously untested schemes, namely Elastic Net regularization, Proximal Gradient Lasso, and Proximal Gradient Elastic Net. Overall, we find that Elastic Net regularization, which combines L1 and L2 regularization, outperforms all other methods with regard to accuracy of traction reconstruction. Next, we develop two methods, Bayesian L2 regularization and Advanced Bayesian L2 regularization, for automatic, optimal L2 regularization. Using artificial data and experimental data, we show that these methods enable robust reconstruction of traction without requiring a difficult selection of regularization parameters specifically for each data set. Thus, Bayesian methods can mitigate the considerable uncertainty inherent in comparing cellular traction forces

    Experiences and psychological strain in volunteer medical doctors providing medical visual examination for asylum seekers in a reception center in Germany - a qualitative interview study

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    Nearly 40% of the refugees arriving in Germany suffer from psychological traumatization. After initial accommodation in reception centers, German legislation requires that all refugees undergo a medical visual examination (MVE) to screen for infectious diseases. This examination is, in part, conducted by volunteering medical doctors. The present study aimed to analyze volunteering medical doctors' motivation for performing MVE, their connected experiences, and their psychological strain in a reception center. In this context, the emergence of secondary traumatic stress, vicarious traumatization, and the need for psychological support were explored. Semistandardized interviews were conducted with 18 medical doctors after they had performed MVE. Interview recordings were transcribed and subsequently underwent qualitative thematic analysis. Finally, thematic clusters were identified. The analysis revealed 512 relevant single codes, from which three main categories were derived. These ranged from private motives for volunteering to perform MVEs in a reception center setting, to thoughts and feelings after performing the examination, and the need for psychosocial support. After having performed MVE, some of the doctors displayed cognitive alterations, which can be an indication of vicarious traumatization. Most participants felt motivated to reflect on their personal beliefs and their moral concepts.</p

    Adhesive Hydrogels for Maxillofacial Tissue Regeneration Using Minimally Invasive Procedures

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    Minimally invasive surgical procedures aiming to repair damaged maxillofacial tissues are hampered by its small, complex structures and difficult surgical access. Indeed, while arthroscopic procedures that deliver regenerative materials and/or cells are common in articulating joints such as the knee, there are currently no treatments that surgically place cells, regenerative factors or materials into maxillofacial tissues to foster bone, cartilage or muscle repair. Here, hyaluronic acid (HA)-based hydrogels are developed, which are suitable for use in minimally invasive procedures, that can adhere to the surrounding tissue, and deliver cells and potentially drugs. By modifying HA with both methacrylate (MA) and 3,4-dihydroxyphenylalanine (Dopa) groups using a completely aqueous synthesis route, it is shown that MA-HA-Dopa hydrogels can be applied under aqueous conditions, gel quickly using a standard surgical light, and adhere to tissue. Moreover, upon oxidation of the Dopa, human marrow stromal cells attach to hydrogels and survive when encapsulated within them. These observations show that when incorporated into HA-based hydrogels, Dopa moieties can foster cell and tissue interactions, ensuring surgical placement and potentially enabling delivery/recruitment of regenerative cells. The findings suggest that MA-HA-Dopa hydrogels may find use in minimally invasive procedures to foster maxillofacial tissue repair.</p

    Platelet Serotonin Aggravates Myocardial Ischemia/Reperfusion Injury via Neutrophil Degranulation

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    Background: Platelets store large amounts of serotonin that they release during thrombus formation or acute inflammation. This facilitates hemostasis and modulates the inflammatory response. Methods: Infarct size, heart function, and inflammatory cell composition were analyzed in mouse models of myocardial reperfusion injury with genetic and pharmacological depletion of platelet serotonin. These studies were complemented by in vitro serotonin stimulation assays of platelets and leukocytes in mice and men, and by measuring plasma serotonin levels and leukocyte activation in patients with acute coronary syndrome. Results: Platelet-derived serotonin induced neutrophil degranulation with release of myeloperoxidase and hydrogen peroxide (H2O2) and increased expression of membrane-bound leukocyte adhesion molecule CD11b, leading to enhanced inflammation in the infarct area and reduced myocardial salvage. In patients hospitalized with acute coronary syndrome, plasmatic serotonin levels correlated with CD11b expression on neutrophils and myeloperoxidase plasma levels. Long-term serotonin reuptake inhibition - reported to protect patients with depression from cardiovascular events - resulted in the depletion of platelet serotonin stores in mice. These mice displayed a reduction in neutrophil degranulation and preserved cardiac function. In line, patients with depression using serotonin reuptake inhibition, presented with suppressed levels of CD11b surface expression on neutrophils and lower myeloperoxidase levels in blood. Conclusions: Taken together, we identify serotonin as a potent therapeutic target in neutrophil-dependent thromboinflammation during myocardial reperfusion injury.Fil: Mauler, Maximilian. No especifíca;Fil: Herr, Nadine. No especifíca;Fil: Schoenichen, Claudia. No especifíca;Fil: Witsch, Thilo. No especifíca;Fil: Marchini, Timoteo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Härdtner, Carmen. No especifíca;Fil: Koentges, Christoph. No especifíca;Fil: Kienle, Korbinian. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ollivier, Véronique. Inserm; FranciaFil: Schell, Maximilian. No especifíca;Fil: Dorner, Ludwig. No especifíca;Fil: Wippel, Christopher. No especifíca;Fil: Stallmann, Daniela. No especifíca;Fil: Normann, Claus. No especifíca;Fil: Bugger, Heiko. No especifíca;Fil: Walther, Paul. Universitat Ulm; AlemaniaFil: Wolf, Dennis. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Ahrens, Ingo. No especifíca;Fil: Lämmermann, Tim. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ho-Tin-Noé, Benoît. Inserm; FranciaFil: Ley, Klaus. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Bode, Christoph. No especifíca;Fil: Hilgendorf, Ingo. No especifíca;Fil: Duerschmied, Daniel. No especifíca

    The FERM protein EPB41L5 regulates actomyosin contractility and focal adhesion formation to maintain the kidney filtration barrier

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    Podocytes form the outer part of the glomerular filter, where they have to withstand enormous transcapillary filtration forces driving glomerular filtration. Detachment of podocytes from the glomerular basement membrane precedes most glomerular diseases. However, little is known about the regulation of podocyte adhesion in vivo. Thus, we systematically screened for podocyte-specific focal adhesome (FA) components, using genetic reporter models in combination with iTRAQ-based mass spectrometry. This approach led to the identification of FERM domain protein EPB41L5 as a highly enriched podocyte-specific FA component in vivo. Genetic deletion of Epb41l5 resulted in severe proteinuria, detachment of podocytes, and development of focal segmental glomerulosclerosis. Remarkably, by binding and recruiting the RhoGEF ARGHEF18 to the leading edge, EPB41L5 directly controls actomyosin contractility and subsequent maturation of focal adhesions, cell spreading, and migration. Furthermore, EPB41L5 controls matrix-dependent outside-in signaling by regulating the focal adhesome composition. Thus, by linking extracellular matrix sensing and signaling, focal adhesion maturation, and actomyosin activation EPB41L5 ensures the mechanical stability required for podocytes at the kidney filtration barrier. Finally, a diminution of EPB41L5-dependent signaling programs appears to be a common theme of podocyte disease, and therefore offers unexpected interventional therapeutic strategies to prevent podocyte loss and kidney disease progression

    Podocytes maintain high basal levels of autophagy independent of mTOR signaling

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    While constant basal levels of macroautophagy/autophagy are a prerequisite to preserve long-lived podocytes at the filtration barrier, MTOR regulates at the same time podocyte size and compensatory hypertrophy. Since MTOR is known to generally suppress autophagy, the apparently independent regulation of these two key pathways of glomerular maintenance remained puzzling. We now report that long-term genetic manipulation of MTOR activity does in fact not influence high basal levels of autophagy in podocytes either in vitro or in vivo. Instead we present data showing that autophagy in podocytes is mainly controlled by AMP-activated protein kinase (AMPK) and ULK1 (unc-51 like kinase 1). Pharmacological inhibition of MTOR further shows that the uncoupling of MTOR activity and autophagy is time dependent. Together, our data reveal a novel and unexpected cell-specific mechanism, which permits concurrent MTOR activity as well as high basal autophagy rates in podocytes. Thus, these data indicate manipulation of the AMPK-ULK1 axis rather than inhibition of MTOR as a promising therapeutic intervention to enhance autophagy and preserve podocyte homeostasis in glomerular diseases

    Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

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    Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen
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