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959 Publications visible to you, out of a total of 959
Fibrinogen is not a prognostic factor for response to HELP-apheresis in sudden sensorineural hearing loss (SSHL)
Genetical Statistics and Systems Biology

Abstract (Expand)

Higher levels of fibrinogen or cholesterol were associated with improved hearing recovery in SSHL patients after treatment with HELP-apheresis (Heparin-induced extracorporeal LDL precipitation apheresis). … The present trial was performed to demonstrate HELP-related effects on relevant metabolic and inflammatory parameters in the context of SSHL treatment. In the framework of a single arm non-controlled trial, we investigated the variation of metabolic and inflammatory parameters using HELP-apheresis for a defined group of 100 patients with SSHL. Based on cut off inclusion criteria (Serum LDL-cholesterol >1.6 g/l and/or fibrinogen >2.0 g/l, SSHL in minimum three frequencies more than 30 dB, time after event not longer than 6 days), the protocol followed a strict time line with one single shot HELP-apheresis and follow-up monitoring including laboratory parameters at six defined time points. If HELP-apheresis could not effect improvement of hearing on day 5, additional corticosteroid treatment was applied. Concentration of anti-inflammatory IL-10 increased while other proinflammatory parameters declined. Serum levels of all measured sterols and apolipoproteins decreased significantly. None of the investigated parameters were suitable to predict hearing improvement of the patients. Levels of fibrinogen and LDL-cholesterol were not prognostic for outcome after HELP-apheresis. A significant (p < 0.001) increase of anti-inflammatory IL-10 after apheresis was notable, while most of the proinflammatory parameters declined. Despite the limited validity of a single arm non-controlled trial, these alterations on immune modulating factors indicate possible secondary pleiotropic effects caused by HELP-apheresis.

Authors: T. Berger, T. Kaiser, M. Scholz, A. Bachmann, U. Ceglarek, G. Hesse, B. Hagemeyer, M. Stumvoll, J. Thiery, A. Dietz

Date Published: 1st Dec 2015

Publication Type: Journal article

Predictors of students’ self-reported adoption of a smartphone application for medical education in general practice
Management of health information systems

Abstract (Expand)

BACKGROUND: Smartphones and related applications are increasingly gaining relevance in the healthcare domain. We previously assessed the demands and preferences of medical students towards an application … accompanying them during a course on general practice. The current study aims to elucidate the factors associated with adoption of such a technology. Therefore we provided students with a prototype of an application specifically related to their studies in general practice. METHODS: A total estimation among students participating in a general practice examination at the Leipzig Medical School was conducted in May 2014. Students were asked to answer a structured self-designed questionnaire. Univariable comparisons were made to identify significant differences between those students who reported to have used the application frequently and those who did not. Multivariable binary logistic regression was used to reveal independent predictors of frequent application usage. RESULTS: The response rate was 99.3 % (n = 305/307). The majority (59 %, n = 180/305) were female students. The mean age was 24.5 years and 79.9 % (n = 243/304) owned a smartphone or tablet computer. Regarding the usage of the provided application, 2.3 % (n = 7/303) did not use the app while 68.0 % (n = 206/303) replied to have used it more than five times. Frequent users significantly differed from non-frequent users with regard to being female rather than male, higher mobile device ownership, more frequent exchange about obtaining the course certificate, higher personal interest in new technologies, larger enjoyment of the technology, lower intention to not use smartphone applications in the future, better opinion towards smartphone applications for the profession of a doctor, higher perceived importance of medical applications on the job, higher compatibility of smartphone applications with personal work style, higher perceived relevance of university support and personal benefit of use. Multivariable analysis revealed a set of four variables independently predicting frequent usage: being female, a higher perceived benefit of the supplied application, a higher personal interest in new technologies, and a higher perceived impact of previous experiences on smartphone adoption (Pseudo-R(2) Nagelkerke = 0.245). CONCLUSIONS: Understanding medical students’ adoption of smartphone applications used for educational purposes may provide useful information to guide the implementation process as well as the design of respective applications.

Authors: M. Sandholzer, T. Deutsch, T. Frese, Alfred Winter

Date Published: 1st Dec 2015

Publication Type: Journal article

Identifying neural correlates of visual consciousness with ALE meta-analyses.
LIFE Adult

Abstract (Expand)

Neural correlates of consciousness (NCC) have been a topic of study for nearly two decades. In functional imaging studies, several regions have been proposed to constitute possible candidates for NCC, … but as of yet, no quantitative summary of the literature on NCC has been done. The question whether single (striate or extrastriate) regions or a network consisting of extrastriate areas that project directly to fronto-parietal regions are necessary and sufficient neural correlates for visual consciousness is still highly debated [e.g., Rees et al., 2002, Nat Rev. Neurosci 3, 261-270; Tong, 2003, Nat Rev. Neurosci 4, 219-229]. The aim of this work was to elucidate this issue and give a synopsis of the present state of the art by conducting systematic and quantitative meta-analyses across functional magnetic resonance imaging (fMRI) studies using several standard paradigms for conscious visual perception. In these paradigms, consciousness is operationalized via perceptual changes, while the visual stimulus remains invariant. An activation likelihood estimation (ALE) meta-analysis was performed, representing the best approach for voxel-wise meta-analyses to date. In addition to computing a meta-analysis across all paradigms, separate meta-analyses on bistable perception and masking paradigms were conducted to assess whether these paradigms show common or different NCC. For the overall meta-analysis, we found significant clusters of activation in inferior and middle occipital gyrus; fusiform gyrus; inferior temporal gyrus; caudate nucleus; insula; inferior, middle, and superior frontal gyri; precuneus; as well as in inferior and superior parietal lobules. These results suggest a subcortical-extrastriate-fronto-parietal network rather than a single region that constitutes the necessary NCC. The results of our exploratory paradigm-specific meta-analyses suggest that this subcortical-extrastriate-fronto-parietal network might be differentially activated as a function of the paradigms used to probe for NCC.

Authors: S. Bisenius, S. Trapp, J. Neumann, M. L. Schroeter

Date Published: 15th Nov 2015

Publication Type: Not specified

Neural synchrony indexes impaired motor slowing after errors and novelty following white matter damage.
LIFE Adult

Abstract (Expand)

In humans, action errors and perceptual novelty elicit activity in a shared frontostriatal brain network, allowing them to adapt their ongoing behavior to such unexpected action outcomes. Healthy and … pathologic aging reduces the integrity of white matter pathways that connect individual hubs of such networks and can impair the associated cognitive functions. Here, we investigated whether structural disconnection within this network because of small-vessel disease impairs the neural processes that subserve motor slowing after errors and novelty (post-error slowing, PES; post-novel slowing, PNS). Participants with intact frontostriatal circuitry showed increased right-lateralized beta-band (12-24 Hz) synchrony between frontocentral and frontolateral electrode sites in the electroencephalogram after errors and novelty, indexing increased neural communication. Importantly, this synchrony correlated with PES and PNS across participants. Furthermore, such synchrony was reduced in participants with frontostriatal white matter damage, in line with reduced PES and PNS. The results demonstrate that behavioral change after errors and novelty result from coordinated neural activity across a frontostriatal brain network and that such cognitive control is impaired by reduced white matter integrity.

Authors: J. R. Wessel, M. Ullsperger, H. Obrig, A. Villringer, E. Quinque, M. L. Schroeter, K. J. Bretschneider, K. Arelin, E. Roggenhofer, S. Frisch, T. A. Klein

Date Published: 14th Nov 2015

Publication Type: Not specified

Resting-state functional magnetic resonance imaging of the subthalamic microlesion and stimulation effects in Parkinson's disease: Indications of a principal role of the brainstem.
LIFE Adult

Abstract (Expand)

During implantation of deep-brain stimulation (DBS) electrodes in the target structure, neurosurgeons and neurologists commonly observe a "microlesion effect" (MLE), which occurs well before … initiating subthalamic DBS. This phenomenon typically leads to a transitory improvement of motor symptoms of patients suffering from Parkinson's disease (PD). Mechanisms behind MLE remain poorly understood. In this work, we exploited the notion of ranking to assess spontaneous brain activity in PD patients examined by resting-state functional magnetic resonance imaging in response to penetration of DBS electrodes in the subthalamic nucleus. In particular, we employed a hypothesis-free method, eigenvector centrality (EC), to reveal motor-communication-hubs of the highest rank and their reorganization following the surgery; providing a unique opportunity to evaluate the direct impact of disrupting the PD motor circuitry in vivo without prior assumptions. Penetration of electrodes was associated with increased EC of functional connectivity in the brainstem. Changes in connectivity were quantitatively related to motor improvement, which further emphasizes the clinical importance of the functional integrity of the brainstem. Surprisingly, MLE and DBS were associated with anatomically different EC maps despite their similar clinical benefit on motor functions. The DBS solely caused an increase in connectivity of the left premotor region suggesting separate pathophysiological mechanisms of both interventions. While the DBS acts at the cortical level suggesting compensatory activation of less affected motor regions, the MLE affects more fundamental circuitry as the dysfunctional brainstem predominates in the beginning of PD. These findings invigorate the overlooked brainstem perspective in the understanding of PD and support the current trend towards its early diagnosis.

Authors: S. Holiga, K. Mueller, H. E. Moller, D. Urgosik, E. Ruzicka, M. L. Schroeter, R. Jech

Date Published: 29th Oct 2015

Publication Type: Not specified

Human Diseases: Parkinson's disease

Brain Arousal Regulation in Carriers of Bipolar Disorder Risk Alleles.
LIFE Adult

Abstract (Expand)

OBJECTIVES: Recent genome-wide association studies identified a number of chromosomal risk loci for bipolar disorder (BD, 'manic-depressive illness'). According to the vigilance regulation … model, the regulation of brain arousal (referred to as 'vigilance') when assessed via EEG is an emerging biomarker linked to the pathogenesis of manic and depressive episodes. On this basis, the present study aimed to assess whether carriers of BD risk alleles differ in brain arousal regulation. METHODS: Healthy participants of the population-based Leipzig Health Care Study (LIFE) underwent a 20-min eyes-closed resting EEG paradigm. Brain arousal was assessed applying the computer-based Vigilance Algorithm Leipzig (VIGALL). The primary sample (n = 540) was genotyped for ten of the most reliable BD risk variants, of which two qualified for replication (n = 509). RESULTS: Primary sample analyses revealed Bonferroni-adjusted significance for rs1006737 in CACNA1C (encoding a calcium channel subunit), with risk allele carriers exhibiting relatively steep brain arousal declines. Further, carriers of two risk alleles of rs472913 at 1p32.1 showed generally lower brain arousal levels for the duration of the resting paradigm. However, both associations failed replication. CONCLUSION: Although our initial findings are in line with the vigilance regulation model and convincing in view of the previously reported notable role of ion channelopathies in BD, our results do not provide consistent evidence for a link between BD risk variants and brain arousal regulation. Several between-sample differences may account for this inconsistency. The molecular genetics of brain arousal regulation remain to be clarified.

Authors: P. Jawinski, C. Sander, N. Mauche, J. Spada, J. Huang, A. Schmidt, M. Hantzsch, R. Burkhardt, M. Scholz, U. Hegerl, T. Hensch

Date Published: 29th Oct 2015

Publication Type: Not specified

Human Diseases: bipolar disorder

First evidence for glial pathology in late life minor depression: S100B is increased in males with minor depression.
LIFE Adult

Abstract (Expand)

Minor depression is diagnosed when a patient suffers from 2 to 4 depressive symptoms for at least 2 weeks. Though minor depression is a widespread phenomenon, its pathophysiology has hardly been studied. … To get a first insight into the pathophysiological mechanisms underlying this disorder we assessed serum levels of biomarkers for plasticity, glial and neuronal function: brain-derived neurotrophic factor (BDNF), S100B and neuron specific enolase (NSE). 27 subjects with minor depressive episode and 82 healthy subjects over 60 years of age were selected from the database of the Leipzig population-based study of civilization diseases (LIFE). Serum levels of BDNF, S100B and NSE were compared between groups, and correlated with age, body-mass index (BMI), and degree of white matter hyperintensities (score on Fazekas scale). S100B was significantly increased in males with minor depression in comparison to healthy males, whereas other biomarkers did not differ between groups (p = 0.10-0.66). NSE correlated with Fazekas score in patients with minor depression (rs = 0.436, p = 0.048) and in the whole sample (rs = 0.252, p = 0.019). S100B correlated with BMI (rs = 0.246, p = 0.031) and with age in healthy subjects (rs = 0.345, p = 0.002). Increased S100B in males with minor depression, without alterations in BDNF and NSE, supports the glial hypothesis of depression. Correlation between white matter hyperintensities and NSE underscores the vascular hypothesis of late life depression.

Authors: M. Polyakova, C. Sander, K. Arelin, L. Lampe, T. Luck, M. Luppa, J. Kratzsch, K. T. Hoffmann, S. Riedel-Heller, A. Villringer, P. Schoenknecht, M. L. Schroeter

Date Published: 27th Oct 2015

Publication Type: Not specified

Human Diseases: mental depression

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