Publications by authors named "Sommer I"

Motivation: We introduce a new approach to using the information contained in sequence-to-function prediction data in order to recognize protein template classes, a critical step in predicting protein structure. The data on which our method is based comprise probabilities of functional categories; for given query sequences these probabilities are obtained by a neural net that has previously been trained on a variety of functionally important features. On a training set of sequences we assess the relevance of individual functional categories for identifying a given structural family.

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Summary: The Helmholtz Network for Bioinformatics (HNB) is a joint venture of eleven German bioinformatics research groups that offers convenient access to numerous bioinformatics resources through a single web portal. The 'Guided Solution Finder' which is available through the HNB portal helps users to locate the appropriate resources to answer their queries by employing a detailed, tree-like questionnaire. Furthermore, automated complex tool cascades ('tasks'), involving resources located on different servers, have been implemented, allowing users to perform comprehensive data analyses without the requirement of further manual intervention for data transfer and re-formatting.

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Febit AG develops an integrated benchtop instrument for in situ microarrays preparation, hybridization, readout and data analysis.

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The problem of computing the tertiary structure of a protein from a given amino acid sequence has been a major subject of bioinformatics research during the last decade. Many different approaches have been taken to tackle the problem, the most successful of which are based on searching databases to identify a similar amino acid sequence in the PDB and using the corresponding structure as a template for modeling the structure of the query sequence. An important advance for the evaluation of sequence similarity in this context has been the use of a frequency profile that represents a part of the protein sequence space close to the query sequence instead of the query sequence itself.

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Gender differences in schizophrenia are among the most consistently reported findings in schizophrenia research. However, the biological substrate underlying these gender differences is still largely unknown. Differences in language lateralization between men and women may underlie some gender differences in schizophrenia.

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An unexpectedly high percentage of monozygotic twin pairs is discordant for handedness. Some of these twins show mirror-imaging of several ectodermally derived features. Both features of discordant left-right asymmetry may be caused by relatively late monozygotic twinning, when the original embryo has already lost its bilateral symmetry.

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Motivation: We present an extensive evaluation of different methods and criteria to detect remote homologs of a given protein sequence. We investigate two associated problems: first, to develop a sensitive searching method to identify possible candidates and, second, to assign a confidence to the putative candidates in order to select the best one. For searching methods where the score distributions are known, p-values are used as confidence measure with great success.

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Anatomical studies have shown that cerebral asymmetry is reduced in schizophrenia. Functional asymmetry appears to be reduced also, as was shown with dichotic listening studies. These studies, however, have not revealed whether reduced lateralization is the result of decreased language activity of the left hemisphere or whether it is the consequence of increased language-related activity in the right hemisphere.

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Recent advances in functional neuroimaging techniques have prompted an increase in the number of studies investigating lateralization of language functions. One of the problems in relating findings of various studies to one another is the diversity of reported results. This may be due to differences in the tasks that are used to stimulate language processing regions and in the control tasks, as well as differences in the way imaging data are analyzed,in particular the threshold for significance of signal change.

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Angiotropic large B cell lymphoma (angiotropic LCL) or intravascular large cell lymphoma (IVLCL) was diagnosed by liver and bone marrow biopsies and immunohistochemical studies in a 52 year old Caucasian male. IVLCL is a very rare disease characterized by widespread intravascular proliferation of lymphoma cells. Although it most commonly affects the central nervous system or skin and occasionally bone marrow, angiotropic LCL may be present without evidence of localized disease, as seen initially in our patient.

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Background: Cerebral lateralisation appears to be decreased in schizophrenia. Results of studies investigating this, however, are equivocal.

Aims: To review quantitatively the literature on decreased lateralisation in schizophrenia.

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Newborns (N = 83) were presented with 3 conditions, each for 160 sec: tongue protrusion (TP), mouth opening (MO), and control (CO). In TP and MO, a female model alternated between demonstrating the gesture for 20 sec and presenting a passive, motionless face for 20 sec. In CO, she presented a passive face in both the "demonstration" and "passive" intervals.

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The Escherichia coli 23 S and 5 S rRNA molecules have been fitted helix by helix to a cryo-electron microscopic (EM) reconstruction of the 50 S ribosomal subunit, using an unfiltered version of the recently published 50 S reconstruction at 7.5 A resolution. At this resolution, the EM density shows a well-defined network of fine structural elements, in which the major and minor grooves of the rRNA helices can be discerned at many locations.

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A healthy monozygotic twin of discordant handedness was scanned with functional magnetic resonance imaging during a language and a mental rotation task. Mirror-imaging was found for both cerebral functions.

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In Alzheimer's disease (AD) there is neuronal loss in the locus ceruleus (LC), and the noradrenergic system may be even more affected in depressed AD patients. However, this neuronal loss may go together with an increase in activity of the remaining noradrenergic neurons. We prospectively evaluated 16 AD patients (6 depressed, 5 transiently depressed, and 5 nondepressed) and 10 controls.

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Background: Depression, one of the most frequent psychiatric disturbances in Alzheimer disease (AD), is proposed to have its neurobiological basis in neuron loss in the noradrenergic locus coeruleus, although this is not the case in idiopathic depression.

Methods: We performed image analyzer-assisted morphometry of the locus coeruleus in 6 depressed, 6 transiently depressed, and 6 nondepressed patients with AD and in 8 control subjects, emphasizing longitudinal psychiatric evaluations and matching for the clinical and neuropathological severity of dementia.

Results: The mean (+/-SD) number of pigmented neurons in the locus coeruleus in controls (11 607+/-946) was higher than in patients with AD, regardless of being depressed (5165+/-928; P=.

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An outbreak of American cutaneous leishmaniasis has been occurred in military training unit localized in 'Zona da Mata' of Pernambuco State, Brazil, where were registered 26 human cases. An epidemiological survey was carried out by entomological investigation and Montenegro skin test (MST). Lutzomyia choti presents predominance (89.

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The reported prevalence of depression concomitant with Parkinson's disease varies greatly in the literature, which may partly be explained by symptom overlap. To determine the impact of symptom overlap on the prevalence, the authors tested 100 Parkinson's disease patients for major depression (DSM-III-R) with both a standard, inclusive method and a diagnostic-etiologic, exclusive method. The authors found that the prevalence detected with the inclusive method (23%) decreased when the exclusive method was used (13%), which was mainly caused by lower scores on the item "loss of interest.

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The aim of this study was to identify developmentally regulated immunocytochemical markers to assess development in the cervical spinal cord of Monodelphis domestica. We demonstrate that two commercially available antibodies exhibit altered patterns of distribution during early postnatal development. Although neurofilament staining was present at birth, only the phosphorylated form, recognised by monoclonal antibodies 2F11 or SMI31 could be detected.

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Little is known about the natural course of arachnoidal cysts (AC) and the incidence of complications. This poses a problem in selection of patients for surgical interventions. The present authors report on 19 children with supratentorial AC of varying location and size.

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Mutations in the gene for proteolipid protein (PLP) have been associated with CNS dysmyelination and abnormal oligodendrocyte death in spontaneous mouse mutants and in Pelizaeus-Merzbacher disease; however, the effect of mutations on PLP structure and function are little understood. We have identified a monoclonal antibody directed against a novel cell surface epitope of PLP, termed O10. By immunofluorescence analysis, COS-7 cells transiently transfected to express PLP (or its isoform DM20) can be stained with antibody O10 and another antibody (A431) directed against the C terminus of PLP/DM20.

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DM-20, a product of the proteolipid protein (plp) gene, has been demonstrated in the spinal cord of the mouse embryo as early as embryonic day 12 (E12) in certain cells, some of which are identifiable as oligodendrocyte progenitors. The present work uses optic pathways of rat and mouse as well-characterized systems for the study of gliogenesis. plp gene expression was monitored with a combination of reverse transcriptase polymerase chain reaction, in situ hybridization, and immunostaining with antibodies to different PLP peptide sequences, combined with O-2A lineage markers.

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In a previous study we demonstrated that differentiation and development of mouse oligodendrocytes is similar to that of the rat after the stage at which O4 is acquired. In this present study we compare directly the early differentiation of oligodendrocytes in the mouse and rat post natal optic nerve and show that the two species differ at the O-2A progenitor and proligodendroblast stages. Mouse progenitors show a variety of morphologies compared to the typical bipolar appearance in the rat.

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The role of the cytoskeleton and cell attachments in the alignment of baby hamster kidney fibroblasts to ridge and groove substratum topography was investigated using confocal scanning microscopy. This was carried out with normal cells and cells treated with the cytoskeleton modifiers cytochalasin D, colcemid, and taxol. Actin was localised with fluorescent phalloidin.

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