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    Peter Weber

    Depression risk is exacerbated by genetic factors and stress exposure; however, the biological mechanisms through which these factors interact to confer depression risk are poorly understood. One putative biological mechanism implicates... more
    Depression risk is exacerbated by genetic factors and stress exposure; however, the biological mechanisms through which these factors interact to confer depression risk are poorly understood. One putative biological mechanism implicates variability in the ability of cortisol, released in response to stress, to trigger a cascade of adaptive genomic and non-genomic processes through glucocorticoid receptor (GR) activation. Here, we demonstrate that common genetic variants in long-range enhancer elements modulate the immediate transcriptional response to GR activation in human blood cells. These functional genetic variants increase risk for depression and co-heritable psychiatric disorders. Moreover, these risk variants are associated with inappropriate amygdala reactivity, a transdiagnostic psychiatric endophenotype and an important stress hormone response trigger. Network modeling and animal experiments suggest that these genetic differences in GR-induced transcriptional activation m...
    Genomic copy number variants (CNVs) have been implicated in multiple psychiatric disorders, but not much is known about their influence on anxiety disorders specifically. Using next-generation sequencing (NGS) and two additional... more
    Genomic copy number variants (CNVs) have been implicated in multiple psychiatric disorders, but not much is known about their influence on anxiety disorders specifically. Using next-generation sequencing (NGS) and two additional array-based genotyping approaches, we detected CNVs in a mouse model consisting of two inbred mouse lines showing high (HAB) and low (LAB) anxiety-related behavior, respectively. An influence of CNVs on gene expression in the central (CeA) and basolateral (BLA) amygdala, paraventricular nucleus (PVN), and cingulate cortex (Cg) was shown by a two-proportion Z-test (p = 1.6 x 10-31), with a positive correlation in the CeA (p = 0.0062), PVN (p = 0.0046) and Cg (p = 0.0114), indicating a contribution of CNVs to the genetic predisposition to trait anxiety in the specific context of HAB/LAB mice. In order to confirm anxiety-relevant CNVs and corresponding genes in a second mouse model, we further examined CD-1 outbred mice. We revealed the distribution of CNVs by ...
    To compare long-term outcome of children and young adults with arterial ischemic stroke (AIS) from 2 large registries. Prospective cohort study comparing functional and psychosocial long-term outcome (≥2 years after AIS) in patients who... more
    To compare long-term outcome of children and young adults with arterial ischemic stroke (AIS) from 2 large registries. Prospective cohort study comparing functional and psychosocial long-term outcome (≥2 years after AIS) in patients who had AIS during childhood (1 month-16 years) or young adulthood (16.1-45 years) between January 2000 and December 2008, who consented to follow-up. Data of children were collected prospectively in the Swiss Neuropediatric Stroke Registry, young adults in the Bernese stroke database. Follow-up information was available in 95/116 children and 154/187 young adults. Median follow-up of survivors was 6.9 years (interquartile range 4.7-9.4) and did not differ between the groups (p = 0.122). Long-term functional outcome was similar (p = 0.896): 53 (56%) children and 84 (55%) young adults had a favorable outcome (modified Rankin Scale 0-1). Mortality in children was 14% (13/95) and in young adults 7% (11/154) (p = 0.121) and recurrence rate did not differ (p = 0.759). Overall psychosocial impairment and quality of life did not differ, except for more behavioral problems among children (13% vs 5%, p = 0.040) and more frequent reports of an impact of AIS on everyday life among adults (27% vs 64%, p < 0.001). In a multivariate regression analysis, low Pediatric NIH Stroke Scale/NIH Stroke Scale score was the most important predictor of favorable outcome (p < 0.001). There were no major differences in long-term outcome after AIS in children and young adults for mortality, disability, quality of life, psychological, or social variables.
    Accurate diagnosis of febrile seizures in children presenting after paroxysmal episodes associated with fever, is hampered by the lack of objective postictal biomarkers. The aim of our study was to investigate whether FS are associated... more
    Accurate diagnosis of febrile seizures in children presenting after paroxysmal episodes associated with fever, is hampered by the lack of objective postictal biomarkers. The aim of our study was to investigate whether FS are associated with increased levels of serum copeptin, a robust marker of arginine vasopressin secretion. This was a prospective emergency-setting cross-sectional study of 161 children between six months and five years of age. Of these, 83 were diagnosed with febrile seizures, 69 had a febrile infection without seizures and nine had epileptic seizures not triggered by infection. Serum copeptin and prolactin levels were measured in addition to standard clinical, neurophysiological, and laboratory assessment. Clinical Trial Registration: NCT01884766. Circulating copeptin was significantly higher in children with febrile seizures (median [interquartile range] 18.9 pmol/L [8.5-36.6]) compared to febrile controls (5.6 pmol/L [4.1-9.4]; p <0.001), with no differences ...
    Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disorder of the pyrimidine degradation pathway. In a patient presenting with convulsions, psychomotor retardation and Reye like syndrome, strongly elevated levels... more
    Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disorder of the pyrimidine degradation pathway. In a patient presenting with convulsions, psychomotor retardation and Reye like syndrome, strongly elevated levels of uracil and thymine were detected in urine. No DPD activity could be detected in peripheral blood mononuclear cells. Analysis of the gene encoding DPD (DPYD) showed that the patient was
    Photosynthetic microbial mats are complex, stratified ecosystems in which high rates of primary production create a demand for nitrogen, met partially by N₂ fixation. Dinitrogenase reductase (nifH) genes and transcripts from Cyanobacteria... more
    Photosynthetic microbial mats are complex, stratified ecosystems in which high rates of primary production create a demand for nitrogen, met partially by N₂ fixation. Dinitrogenase reductase (nifH) genes and transcripts from Cyanobacteria and heterotrophic bacteria (for example, Deltaproteobacteria) were detected in these mats, yet their contribution to N2 fixation is poorly understood. We used a combined approach of manipulation experiments with inhibitors, nifH sequencing and single-cell isotope analysis to investigate the active diazotrophic community in intertidal microbial mats at Laguna Ojo de Liebre near Guerrero Negro, Mexico. Acetylene reduction assays with specific metabolic inhibitors suggested that both sulfate reducers and members of the Cyanobacteria contributed to N₂ fixation, whereas (15)N₂ tracer experiments at the bulk level only supported a contribution of Cyanobacteria. Cyanobacterial and nifH Cluster III (including deltaproteobacterial sulfate reducers) sequence...
    Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of... more
    Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico-permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)-were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic pho...
    High spatial-resolution secondaryion microprobespectrometry, synchrotron radiation Fourier-transform infraredspectroscopy and polyacrylamide gel analysis demonstrate the intimateassociation of proteins with spheroidal aggregates of... more
    High spatial-resolution secondaryion microprobespectrometry, synchrotron radiation Fourier-transform infraredspectroscopy and polyacrylamide gel analysis demonstrate the intimateassociation of proteins with spheroidal aggregates of biogenic zincsulfide nanocrystals, an example of extracellular biomineralization.Experiments involving synthetic ZnS nanoparticles and representativeamino acids indicate a driving role for cysteine in rapid nanoparticleaggregation. These findings suggest that microbially-derivedextracellular proteins can limit dispersal of nanoparticulatemetal-bearing phases, such as the
    To examine phylogenetic identity and metabolic activity of individual cells in complex microbial communi- ties, we developed a method which combines rRNA-based in situ hybridization with stable isotope imaging based on nanometer-scale... more
    To examine phylogenetic identity and metabolic activity of individual cells in complex microbial communi- ties, we developed a method which combines rRNA-based in situ hybridization with stable isotope imaging based on nanometer-scale secondary-ion mass spectrometry (NanoSIMS). Fluorine or bromine atoms were introduced into cells via 16S rRNA-targeted probes, which enabled phylogenetic identification of individual cells by NanoSIMS imaging. To overcome
    A method for wideband measurement and for post-processing of mobile radio channel impulse responses which include unambiguous information about the directions-of-arrival in the azimuth is introduced. Based on this method, measurement... more
    A method for wideband measurement and for post-processing of mobile radio channel impulse responses which include unambiguous information about the directions-of-arrival in the azimuth is introduced. Based on this method, measurement results for outdoor macrocellular environments are presented. These results are essential for assessing, developing, evaluating and optimizing adaptive directional antenna concepts for future mobile radio systems and for extending
    In the past years, there has been growing awareness about childhood onset multiple sclerosis (MS) and the relevance of psychosocial aspects such as cognitive disturbances, fatigue and depression in this population. We describe a case of a... more
    In the past years, there has been growing awareness about childhood onset multiple sclerosis (MS) and the relevance of psychosocial aspects such as cognitive disturbances, fatigue and depression in this population. We describe a case of a 16-year-old patient with relapsing-remitting multiple sclerosis (RRMS) who presented at our clinic with severe fatigue symptoms and who underwent repeated neuropsychological examinations. A sudden significant slowing indicated a new relapse while neurological examination did not. This case highlights the high sensitivity and clinical relevance of neuropsychological testing in patients with juvenile MS even in the context of treatment decisions.
    A large series of coumarin derivatives (71 compounds) were tested for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory activity. Most of the compounds acted preferentially on MAO-B with IC(50) values in the micromolar to... more
    A large series of coumarin derivatives (71 compounds) were tested for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory activity. Most of the compounds acted preferentially on MAO-B with IC(50) values in the micromolar to low-nanomolar range; high inhibitory activities toward MAO-A were also measured for sulfonic acid esters. The most active compound was 7-[(3, 4-difluorobenzyl)oxy]-3,4-dimethylcoumarin, with an IC(50) value toward MAO-B of 1.14 nM. A QSAR study of 7-X-benzyloxy meta-substituted 3,4-dimethylcoumarin derivatives acting on MAO-B yielded good statistical results (q(2)() = 0.72, r(2)() = 0.86), revealing the importance of lipophilic interactions in modulating the inhibition and excluding any dependence on electronic properties. CoMFA was performed on two data sets of MAO-A and MAO-B inhibitors. The GOLPE procedure, with variable selection criteria, was applied to improve the predictivity of the models and to facilitate the graphical interpretation of results.
    Mutations of the SET binding protein 1 gene (SETBP1) on 18q12.3 have recently been reported to cause Schinzel-Giedion syndrome (SGS). As rare 18q interstitial deletions affecting multiple genes including SETBP1 correlate with a milder... more
    Mutations of the SET binding protein 1 gene (SETBP1) on 18q12.3 have recently been reported to cause Schinzel-Giedion syndrome (SGS). As rare 18q interstitial deletions affecting multiple genes including SETBP1 correlate with a milder phenotype, including minor physical anomalies and developmental and expressive speech delay, mutations in SETBP1 are thought to result in a gain-of-function or a dominant-negative effect. However, the consequence of the SETBP1 loss-of-function has not yet been well described. Microarray-based comparative genomic hybridisation (aCGH) analyses were performed to identify genetic causes for developmental and expressive speech delay in two patients. SETBP1 expression in fibroblasts obtained from one of the patients was analysed by real-time RT-PCR and western blotting. A cohort study to identify nucleotide changes in SETBP1 was performed in 142 Japanese patients with developmental delay. aCGH analyses identified submicroscopic deletions of less than 1 Mb exclusively containing SETBP1. Both patients show global developmental, expressive language delay and minor facial anomalies. Decreased expression of SETBP1 was identified in the patient's skin fibroblasts. No pathogenic mutation of SETBP1 was identified in the cohort study. SETBP1 expression was reduced in a patient with SETBP1 haploinsufficiency, indicating that the SETBP1 deletion phenotype is allele dose sensitive. In correlation with the exclusive deletion of SETBP1, this study delimits a milder phenotype distinct from SGS overlapping with the previously described phenotype of del(18)(q12.2q21.1) syndrome including global developmental, expressive language delay and distinctive facial features. These findings support the hypothesis that mutations in SETBP1 causing SGS may have a gain-of-function or a dominant-negative effect, whereas haploinsufficiency or loss-of-function mutations in SETBP1 cause a milder phenotype.
    An extension of Rohling's (1984) single-parameter technique for processing Constant False Alarm Rate (CFAR) based on the ordered statistics of the reference cells, is described. The present version of the technique maintains a CFAR... more
    An extension of Rohling's (1984) single-parameter technique for processing Constant False Alarm Rate (CFAR) based on the ordered statistics of the reference cells, is described. The present version of the technique maintains a CFAR for two-parameter distributions where the mean power and skewness of the system are variable. It is shown that the method is more robust than the single-parameter technique but has higher CFAR loss.
    Although gene expression profiles in peripheral blood in major depression are not likely to identify genes directly involved in the pathomechanism of affective disorders, they may serve as biomarkers for this disorder. As previous studies... more
    Although gene expression profiles in peripheral blood in major depression are not likely to identify genes directly involved in the pathomechanism of affective disorders, they may serve as biomarkers for this disorder. As previous studies using baseline gene expression profiles have provided mixed results, our approach was to use an in vivo dexamethasone challenge test and to compare glucocorticoid receptor (GR)-mediated changes in gene expression between depressed patients and healthy controls. Whole genome gene expression data (baseline and following GR-stimulation with 1.5 mg dexamethasone p.o.) from two independent cohorts were analyzed to identify gene expression pattern that would predict case and control status using a training (N=18 cases/18 controls) and a test cohort (N=11/13). Dexamethasone led to reproducible regulation of 2670 genes in controls and 1151 transcripts in cases. Several genes, including FKBP5 and DUSP1, previously associated with the pathophysiology of majo...
    Recurrent nocturnal behavioural and movement paroxysms are a diagnostic challenge for the clinical pediatrician. We report on an adolescent girl who presents recurrent stereotypical nightmare-like episodes occurring during non-REM sleep... more
    Recurrent nocturnal behavioural and movement paroxysms are a diagnostic challenge for the clinical pediatrician. We report on an adolescent girl who presents recurrent stereotypical nightmare-like episodes occurring during non-REM sleep stages 1-2 (N1 and N2). We discuss the differential diagnoses between epileptic and nonepileptic events and between nocturnal frontal and temporal seizures. The pathophysiological and unusual electroencephalographical features are discussed with respect to clinical features and results of interictal FDG-PET. Conclusion In case of stereotypical nightmare-like episodes in children or adolescents, an epileptic origin has to be ruled out before a parasomnia is diagnosed. In addition, a normal awake EEG or interictal sleep EEG in the diagnostic workup may not exclude an epileptic disorder. In case of nightly stereotypic motor or affective events, an epileptic disorder should be discussed.
    Benign epilepsy with centrotemporal spikes (BECTS) is the most common idiopathic epileptic disorder in children. Besides reported cognitive deficits, functional alterations mostly in the reorganization of language areas have also been... more
    Benign epilepsy with centrotemporal spikes (BECTS) is the most common idiopathic epileptic disorder in children. Besides reported cognitive deficits, functional alterations mostly in the reorganization of language areas have also been described. In several publications, it has been reported that activation of the default mode network (DMN) can be reduced or altered in different neuropsychiatric and neurological disorders in adults. Whether this also holds true for children with epilepsy has so far not been clarified. To determine the functional activation of the DMN in children with BECTS, 20 patients and 16 healthy controls were examined using functional magnetic resonance imaging (fMRI), while a sentence generation task and a reading task were applied in a block design manner. To study the default mode network and the functional alterations between groups, an independent component analysis (ICA) was computed and further analyzed using SPM5. Compared with controls, children with BECTS showed not only significantly less activation of the DMN during the rest condition but also less deactivation during cognitive effort. This was most apparent in the precuneus, a key region of the DMN, while subjects were generating sentences. From these findings, we hypothesize that children with BECTS show a functional deficit that is reflected by alterations in the DMN.
    Page 1. Experimental determination of the sources of otolith carbon and associated isotopic fractionation Christopher T. Solomon, Peter K. Weber, Joseph J. Cech, Jr., B. Lynn Ingram, Mark E. Conrad, Madhav V. Machavaram, Asya R. Pogodina,... more
    Page 1. Experimental determination of the sources of otolith carbon and associated isotopic fractionation Christopher T. Solomon, Peter K. Weber, Joseph J. Cech, Jr., B. Lynn Ingram, Mark E. Conrad, Madhav V. Machavaram, Asya R. Pogodina, and Rebecca L. Franklin ...
    ... Lipophilicity in Molecular Modeling Bernard Testa,1'2 Pierre-Alain Carrupt,1 Patrick Gaillard,1 Frédéric Billois,1 and Peter Weber1 Received ... In V. Pliska, B. Testa, and H. van de Waterbeemd (eds.), Lipophil-icity in Drug... more
    ... Lipophilicity in Molecular Modeling Bernard Testa,1'2 Pierre-Alain Carrupt,1 Patrick Gaillard,1 Frédéric Billois,1 and Peter Weber1 Received ... In V. Pliska, B. Testa, and H. van de Waterbeemd (eds.), Lipophil-icity in Drug Research, VCH Publishers, Weinheim, 1996, in press. 16. ...
    To assess possible effects of working memory (WM) training on cognitive functionality, functional MRI and brain connectivity in patients with juvenile MS. Cognitive status, fMRI and inter-network connectivity were assessed in 5 cases with... more
    To assess possible effects of working memory (WM) training on cognitive functionality, functional MRI and brain connectivity in patients with juvenile MS. Cognitive status, fMRI and inter-network connectivity were assessed in 5 cases with juvenile MS aged between 12 and 18 years. Afterwards they received a computerized WM training for four weeks. Primary cognitive outcome measures were WM (visual and verbal) and alertness. Activation patterns related to WM were assessed during fMRI using an N-Back task with increasing difficulty. Inter-network connectivity analyses were focused on fronto-parietal (left and right), default-mode (dorsal and ventral) and the anterior salience network. Cognitive functioning, fMRI and inter-network connectivity were reassessed directly after the training and again nine months following training. Response to treatment was seen in two patients. These patients showed increased performance in WM and alertness after the training. These behavioural changes wer...