180 research outputs found

    Neurogenic Processes Are Induced by Very Short Periods of Voluntary Wheel-Running in Male Mice

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    Even in the adult mammalian brain progenitor cells proliferate and give rise to young neurons which integrate into the neuronal network. The dentate gyrus possesses such a neurogenic niche reactive to external stimuli like physical activity. In most studies mice or rats have been exposed to wheel running for periods of several weeks to activate neurogenesis while early neurogenic processes induced by very short running periods are less well understood. To address this issue, we allowed male C57Bl/6 mice free access to a running wheel for 2 or 7 days. We injected bromodeoxyuridine (BrdU) before the last running night, respectively, and quantified cell proliferation with immunocytochemistry for BrdU and Ki-67. Furthermore, we performed immunocytochemistry for doublecortin (DCX) and real-time RT-qPCR for NeuroD1 to characterize and quantify changes in neurogenesis on the protein and mRNA level. Real-time RT-qPCR for neurogenic niche factors (BDNF, FGF-2, BMP4, Noggin) was used to detect changes in the molecular composition of the neurogenic niche. Interestingly, we observed that cell proliferation was already affected after 2 days of running showing a transient decrease, which was followed by a rebound with increased proliferation after 7 days. Neurogenesis was stimulated after 2 days of running, reflected by elevated NeuroD1 mRNA levels, and it was significantly increased after 7 days as indicated by DCX immunostaining. On the level of niche factors we observed changes in expression in favor of neuronal differentiation (increased BDNF mRNA expression) and proliferation (decreased BMP4 mRNA expression) already after 2 days, although increased proliferation is reflected on the cellular level only later. In summary, our data show that 2 days of running are sufficient to activate neurogenic processes and we hypothesize that a strong pressure toward differentiation privileges neurogenesis while proliferation lags behind

    ORR and OER on Ni-modified Co3O4(111) Cathodes for Zn-Air Batteries - A Combined Surface Science and Electrochemical Model Study

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    The performance of structurally and chemically well‐defined Ni‐free and Ni‐modified single‐crystalline Co3_{3}O4_{4}(1 1 1) thin‐film electrodes in the oxygen reduction and evolution reactions (ORR and OER) was investigated in a combined surface science and electrochemistry approach. Pure and Ni‐modified Co3_{3}O4_{4}(1 1 1) film electrodes were prepared and characterized under ultrahigh‐vacuum conditions by scanning tunneling microscopy and X‐ray photoelectron spectroscopy. Both Ni decoration (by post‐deposition of Ni) and Ni doping (by simultaneous vapor deposition of Ni, Co, and O2_{2}) induced distinct differences in the base cyclic voltammograms in 0.5 m KOH at potentials higher than 0.7 V compared with Co3_{3}O4_{4} (1 1 1) electrodes. Also, all oxide film electrodes showed a higher overpotential for the ORR but a lower one for the OER than polycrystalline Pt. Ni modification significantly improved the ORR current densities by increasing the electrical conductivity, whereas the OER onset of approximately 1.47 VRHE_{RHE} (RHE: reversible hydrogen electrode) at 0.1 mA cm2^{-2} was almost unchanged

    Corynebacterium diphtheriae invasion-associated protein (DIP1281) is involved in cell surface organization, adhesion and internalization in epithelial cells

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    <p>Abstract</p> <p>Background</p> <p><it>Corynebacterium diphtheriae</it>, the causative agent of diphtheria, is well-investigated in respect to toxin production, while little is known about <it>C. diphtheriae </it>factors crucial for colonization of the host. In this study, we investigated the function of surface-associated protein DIP1281, previously annotated as hypothetical invasion-associated protein.</p> <p>Results</p> <p>Microscopic inspection of DIP1281 mutant strains revealed an increased size of the single cells in combination with an altered less club-like shape and formation of chains of cells rather than the typical V-like division forms or palisades of growing <it>C. diphtheriae </it>cells. Cell viability was not impaired. Immuno-fluorescence microscopy, SDS-PAGE and 2-D PAGE of surface proteins revealed clear differences of wild-type and mutant protein patterns, which were verified by atomic force microscopy. DIP1281 mutant cells were not only altered in shape and surface structure but completely lack the ability to adhere to host cells and consequently invade these.</p> <p>Conclusions</p> <p>Our data indicate that DIP1281 is predominantly involved in the organization of the outer surface protein layer rather than in the separation of the peptidoglycan cell wall of dividing bacteria. The adhesion- and invasion-negative phenotype of corresponding mutant strains is an effect of rearrangements of the outer surface.</p

    Classes of depression symptom trajectories in patients with major depression receiving a collaborative care intervention

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    Purpose Collaborative care is effective in improving symptoms of patients with depression. The aims of this study were to characterize symptom trajectories in patients with major depression during one year of collaborative care and to explore associations between baseline characteristics and symptom trajectories. Methods We conducted a cluster-randomized controlled trial in primary care. The collaborative care intervention comprised case management and behavioral activation. We used the Patient Health Questionnaire-9 (PHQ-9) to assess symptom severity as the primary outcome. Statistical analyses comprised latent growth mixture modeling and a hierarchical binary logistic regression model. Results We included 74 practices and 626 patients (310 intervention and 316 control recipients) at baseline. Based on a minimum of 12 measurement points for each intervention recipient, we identified two latent trajectories, which we labeled \u27fast improvers\u27 (60.5%) and \u27slow improvers\u27 (39.5%). At all measurements after baseline, \u27fast improvers\u27 presented higher PHQ mean values than \u27slow improvers\u27. At baseline, \u27fast improvers\u27 presented fewer physical conditions, higher health-related quality of life, and had made fewer suicide attempts in their history. Conclusions A notable proportion of 39.5% of patients improved only \u27slowly\u27 and probably needed more intense treatment. The third follow-up in month two could well be a sensible time to adjust treatment to support \u27slow improvers\u27. (DIPF/Orig.

    Histological Correlates of Diffusion-Weighted Magnetic Resonance Microscopy in a Mouse Model of Mesial Temporal Lobe Epilepsy

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    Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy. It is frequently associated with abnormal MRI findings, which are caused by underlying cellular, structural, and chemical changes at the micro-scale. In the current study, it is investigated to which extent these alterations correspond to imaging features detected by high resolution magnetic resonance imaging in the intrahippocampal kainate mouse model of MTLE. Fixed hippocampal and whole-brain sections of mouse brain tissue from nine animals under physiological and chronically epileptic conditions were examined using structural and diffusion-weighted MRI. Microstructural details were investigated based on a direct comparison with immunohistochemical analyses of the same specimen. Within the hippocampal formation, diffusion streamlines could be visualized corresponding to dendrites of CA1 pyramidal cells and granule cells, as well as mossy fibers and Schaffer collaterals. Statistically significant changes in diffusivities, fractional anisotropy, and diffusion orientations could be detected in tissue samples from chronically epileptic animals compared to healthy controls, corresponding to microstructural alterations (degeneration of pyramidal cells, dispersion of the granule cell layer, and sprouting of mossy fibers). The diffusion parameters were significantly correlated with histologically determined cell densities. These findings demonstrate that high-resolution diffusion-weighted MRI can resolve subtle microstructural changes in epileptic hippocampal tissue corresponding to histopathological features in MTLE

    Corrigendum: Histological Correlates of Diffusion-Weighted Magnetic Resonance Microscopy in a Mouse Model of Mesial Temporal Lobe Epilepsy

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    In the published article, there were errors in affiliations 2 and 3. Instead of “Experimental Epilepsy Research, Department of Neurosurgery, Medical Center – University of Freiburg, Freiburg, Germany” and “Department Neurosurgery, Experimental Epilepsy Research, Medical Center, University of Freiburg, Freiburg, Germany,” they should be “Faculty of Medicine, University of Freiburg, Freiburg, Germany” and “Experimental Epilepsy Research, Department of Neurosurgery, Medical Center – University of Freiburg, Freiburg, Germany,” respectively. The authors apologize for these errors and state that this does not change the scientific conclusions of the article in any way. The original article has been updated

    Emulsion polymerizations for a sustainable preparation of efficient TEMPO‐based electrodes

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    Organic polymer‐based batteries represent a promising alternative to present‐day metal‐based systems and a valuable step toward printable and customizable energy storage devices. However, most scientific work is focussed on the development of new redox‐active organic materials, while straightforward manufacturing and sustainable materials and production will be a necessary key for the transformation to mass market applications. Here, a new synthetic approach for 2,2,6,6‐tetramethyl‐4‐piperinidyl‐ N ‐oxyl (TEMPO)‐based polymer particles by emulsion polymerization and their electrochemical investigation are reported. The developed emulsion polymerization protocol based on an aqueous reaction medium allowed the sustainable synthesis of a redox‐active electrode material, combined with simple variation of the polymer particle size, which enabled the preparation of nanoparticles from 35 to 138 nm. Their application in cell experiments revealed a significant effect of the size of the active‐polymer particles on the performance of poly(2,2,6,6‐tetramethyl‐4‐piperinidyl‐ N ‐oxyl methacrylate) (PTMA)‐based electrodes. In particular rate capabilities were found to be reduced with larger diameters. Nevertheless, all cells based on the different particles revealed the ability to recover from temporary capacity loss due to application of very high charge/discharge rates.Sustainable and efficient organic electrode : A new synthetic approach for polymers for organic batteries includes an emulsion polymerization with adjustable particle sizes in aqueous dispersions and allows the sustainable manufacturing of active materials and composite electrodes. The electrochemical investigation shows that the influence of particle sizes and the resulting morphologies of composite films on the cell performance is as important as the active material itself

    Expression analyses of the mitochondrial complex I 75-kDa subunit in early onset schizophrenia and autism spectrum disorder: increased levels as a potential biomarker for early onset schizophrenia

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    Searching for a peripheral biological marker for schizophrenia, we previously reported on elevated mitochondrial complex I 75-kDa subunit mRNA-blood concentrations in early onset schizophrenia (EOS). The aim of this study was to further evaluate the utility of this gene as a potential marker for schizophrenia. Both—schizophrenia and autism—are suggested to be neuronal maldevelopmental disorders with reports of mitochondrial dysfunction and increased oxidative stress. Therefore we have investigated the expression levels of mitochondrial complex I 75-kDa subunit mRNA in whole blood of children with autistic spectrum disorder (ASD) and a group of adolescent acute first-episode EOS patients in comparison to matched controls. We have found that compared to the respective controls only the group of EOS patients—and not the ASD group—showed a significantly altered expression of the complex I 75-kDa subunit mRNA. Although further studies are necessary to test for the specificity of this marker, our findings point to the potential use of the mitochondrial complex I as a biomarker for schizophrenia
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