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Search Results: 1 - 10 of 190 matches for " Leonie Smeenk "
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Role of p53 Serine 46 in p53 Target Gene Regulation
Leonie Smeenk,Simon J. van Heeringen,Max Koeppel,Bianca Gilbert,Eva Janssen-Megens,Hendrik G. Stunnenberg,Marion Lohrum
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017574
Abstract: The tumor suppressor p53 plays a crucial role in cellular growth control inducing a plethora of different response pathways. The molecular mechanisms that discriminate between the distinct p53-responses have remained largely elusive. Here, we have analyzed the p53-regulated pathways induced by Actinomycin D and Etoposide treatment resulting in more growth arrested versus apoptotic cells respectively. We found that the genome-wide p53 DNA-binding patterns are almost identical upon both treatments notwithstanding transcriptional differences that we observed in global transcriptome analysis. To assess the role of post-translational modifications in target gene choice and activation we investigated the genome-wide level of phosphorylation of Serine 46 of p53 bound to DNA (p53-pS46) and of Serine 15 (p53-pS15). Interestingly, the extent of S46 phosphorylation of p53 bound to DNA is considerably higher in cells directed towards apoptosis while the degree of phosphorylation at S15 remains highly similar. Moreover, our data suggest that following different chemotherapeutical treatments, the amount of chromatin-associated p53 phosphorylated at S46 but not at pS15 is higher on certain apoptosis related target genes. Our data provide evidence that cell fate decisions are not made primarily on the level of general p53 DNA-binding and that post-translationally modified p53 can have distinct DNA-binding characteristics.
Slow Gamma Activity of Local Field Potentials (LFP) in the Freely Moving Rat Relates to Movement  [PDF]
Wilfried Dimpfel, Leonie Schombert
Journal of Behavioral and Brain Science (JBBS) , 2015, DOI: 10.4236/jbbs.2015.510040
Abstract: Quantitative assessment of local field potentials by means of Fast Fourier Transformation (FFT) results in the so-called power density spectrum. Within this spectrum particular frequency ranges are defined in order to relate these to behavior. Frequencies above 35 Hz are generally labeled as gamma oscillations, especially as low gamma (40 - 55 Hz) or high gamma (70 - 100 Hz). In order to learn more about this feature, we implanted a set of 4 bipolar concentric steel electrodes in frontal cortex, hippocampus, striatum and midbrain reticular formation of 10 rats. After recovery, field potentials were recorded and wirelessly transmitted to our computer for frequency analysis. At the same time, motion was registered during the whole experimental period of 5.75 hours. Results revealed that low gamma activity only emerged when the animal moved—at least his head. FFT of the data showed—besides other frequencies—a slow gamma activity peaking around 47 Hz pre-dominantly within the striatum, less in frontal cortex and reticular formation and nearly none in the hippocampus. Spectral analysis was performed for single epochs of 4 seconds and all 15 minutes intervals. Correlation analysis of these intervals was done to motion data. All rats showed a highly significant correlation between gamma activity and movement. We therefore conclude from these experiments that this slow gamma activity of the field potentials is not only related to movement, but possibly part of the general neuronal coding of movement.
Gefühlsgemeinschaft“ – Autobiographische Erinnerungen an den BDM und der Erinnerungsdiskurs Community of Feeling—Autobiographical Memories of the BDM and Memory Discourse
Leonie Wagner
querelles-net , 2008,
Abstract: Gisela Miller-Kipp dokumentiert und analysiert 27 Auszüge aus ver ffentlichten Erinnerungen ehemaliger BDM-Mitglieder mit dem Ziel, deren Empfindungen und Gefühle zu rekonstruieren. Dabei sind interessante Einblicke m glich, die jedoch die von der Autorin intendierte Repr sentativit t nicht einl sen (k nnen). Zudem handelt es sich um Erinnerungen und damit um retrospektiv vorgenommene Konstruktionen, die meist noch mit dem Ziel einer Ver ffentlichung aufgeschrieben wurden. Der Band liefert insofern wichtige Anregungen, ist aber in wissenschaftlicher Hinsicht nicht zufriedenstellend. Gisela Miller-Kipp documents and analyzes 27 excerpts from the published memories of former BDM-members with the goal of reconstructing their feelings and perceptions. This approach makes interesting insights possible but it cannot honor the author’s intended representativeness. In addition, because the book is about memories it presents retrospectively collected constructions that were mostly written down after the fact with the goal of publication. The volume therefore provides important perspectives that are not satisfying in a scientific respect.
Sobre o "envelhecimento" dos "novos" movimentos sociais na Alemanha: Reflec es teóricas acerca de crise, paralisia a fim de um modelo exitoso
Wagner, Leonie
Civitas , 2002,
Abstract: Por volta de meados da década de 1970, a opini o pública e a política na República Federal da Alemanha foram surpreendidas pelo surgimento em grande escala de movimentos sociais. Com uma presen a pública inicialmente em constante crescimento e u efeito mobilizador notável, novos atores entraram em cena e chamaram a aten o para problemas sociais e políticos. O texto persegue a pergunta sobre o que resultou desta irrup o surpreendente, poderosa e cheia de imagina o. O desenvolvimento dos movimentos sociais na América Ocidental é discutido dentro do contexto histórico-político e das teorias sobre movimentos sociais. Com isso pretende-se elucidar influências dos movimentos sociais sobre contextos da sociedade e, ao revés, a import ncia da mudan a na sociedade para os movimentos sociais. Depois de uma vis o panoramica sobre "velhos" e "novos" movimentos sociais na Alemanha, s o analisadas as condi es para o desenvolvimento de novos movimentos sociais na Alemanha Ocidental sob o prisma da institucionaliza o, da mudan a nas formas de a o e de fazer política, das tendências à homogeneiza o e individualiza o, assim como da aceita o da diferen a.
Servi o social e movimentos sociais - uma n o-rela o?
Wagner, Leonie
Civitas , 2004,
Abstract:
Modelling the Financial Value of the Maroochy River to Property Values: An Application of Neural Networks  [PDF]
Andrew HIGGINS, Leonie PEARSON, Luis LAREDO
Journal of Water Resource and Protection (JWARP) , 2009, DOI: 10.4236/jwarp.2009.14029
Abstract: The Maroochy River, which is located on east coast of Australia, provides a variety of uses and values to the community. Changes in structure, function and management of the river will influence the value that the community derives from it. Therefore, critical to the river’s continued management is the development of policy relevant tools based on the community’s value of the river. This paper focuses on estimating the fi-nancial value the local residents derive from living close to the river through investigation of changes in residential property values due to attributes of the Maroochy River. It is a complex analysis since there are several confounding geographical and property variables. Given a large and complete dataset of 28,000 properties for the Maroochy region, Artificial Neural Networks (ANN) was applied to estimate the economic value of the properties. This ANN was then able to simulate scenarios for property values with respect to changes in environmental features. It showed the Maroochy River contributed AU$900,000,000 to the unim-proved capital value of the whole region, a value that could not be estimated previously, and much higher than anticipated. Calculating potential annual payments to the Shire Council through land tax analysis from these property values, provides the council with means to justify expenditure to maintain a standard of water quality and ecosystem health.
Psychophysiological Effects of Sideritis and Bacopa Extract and Three Combinations Thereof—A Quantitative EEG Study in Subjects Suffering from Mild Cognitive Impairment (MCI)  [PDF]
Wilfried Dimpfel, Leonie Schombert, Andreas Biller
Advances in Alzheimer's Disease (AAD) , 2016, DOI: 10.4236/aad.2016.51001
Abstract: Mild cognitive impairment (MCI) is regarded as a transitional stage during the development of Alzheimer’s disease. Diagnosis of MCI can be obtained by the questionnaire “DemTect” in German speaking countries. Quantitative assessment has been successfully performed using psychometric testing concomitantly with quantitative EEG recording. The present investigation aimed at the possible treatment of MCI with two botanicals, namely extracts from Sideritis scardica (500 mg) or Bacopa monnieri (320 mg) and three combinations thereof using this method in order to find a new treatment. The performance of the d2-test, an arithmetic calculation test (CPT) and a memory-test revealed better performance for the d2-test only in the presence of Sideritis extract or the combinations with Bacopa extract. Quantitative EEG assessment during the different experimental conditions showed massive differences between both extracts. Whereas Sideritis extract and its combination with a low amount of Bacopa extract (160 mg) induced increases of spectral power in fronto-temporal brain areas, Bacopa and the combination of Sideritis with high amounts of Bacopa extract produced attenuation of all waves except for delta in fronto-temporal brain areas. These differences were also documented by quantitative EEG maps in comparison to Placebo. A different action of both extracts was confirmed by discriminant analysis, where Sideritis extract and its combination with low Bacopa grouped together quite at distance to Bacopa and the combination of Sideritis with high Bacopa. A combination of Sideritis extract with a low amount of Bacopa should be tested with daily repetitive dosing for at least 4 weeks as a consequence.
Opposite Neurophysiological Findings Induced by Sideritis scardica and Sideritis euboa Extract in the Rat  [PDF]
Wilfried Dimpfel, Bj?rn Feistel, Leonie Schombert
Journal of Behavioral and Brain Science (JBBS) , 2016, DOI: 10.4236/jbbs.2016.611041
Abstract: Psychophysiological effects of Sideritis herba extracts depend on biologically active ingredients, which might be different for several botanical types of this plant. The present investigation aimed at the characterization of extracts from Sideritis scardica and Sideritis euboa in vivo and in vitro. Construction of electropharmacograms on the base of recording of electrical field potentials from four different brain regions was used to compare the possible pharmacological effects to a database of reference drugs with known clinical indications. Whereas Sideritis scardica produced decreases of spectral power in line with stimulatory frequency patterns as observed in the presence of Ginkgo biloba extract, administration of Sideritis euboa produced opposite effects. Electrical stimulation of the Schaffer Collaterals was used to elicit a pyramidal cell response called population spike in vitro. The amplitude of this spike was determined in the presence of single as well as theta burst stimuli. Direct exposure of brain matter to Sideritis scardica extract led to concentration dependent increases of the population spike amplitude under both stimulation patterns in the range from 12.5 to 100 mg/L. On the opposite, extract from Sideritis euboa did not change the electric response up to 50 mg/L. Higher concentrations of this extract attenuated the signal amplitude. A 1:1 blend of both gave intermediate results. The in vitro results are in line with the in vivo EEG recordings, where both extracts induced opposite changes of the electric power with respect to electric frequency patterns. The results from both models suggest a stimulatory and/or memory-enhancing action for the extract from Sideritis scardica but not for Sideritis euboa extract, where a more tranquillizing effect like that observed in the presence of Humulus cone extract may be expected.
Ex Vivo Characterization of the Action of Sideritis Extract Using Electrical Activity in the Rat Hippocampus Slice Preparation  [PDF]
Wilfried Dimpfel, Leonie Schombert, Bj?rn Feistel
Pharmacology & Pharmacy (PP) , 2016, DOI: 10.4236/pp.2016.710048
Abstract:
A hydroethanolic extract (20% V/V) from Herba Sideritis scardica has been recognized to positively influence cognition. The present investigation aimed at the question if this extract would be able to modify intra-hippocampal communication after oral administration of 100 mg/kg daily for one week. The glutamatergic synapse between Schaffer Collaterals and pyramidal cells can be tested by electric stimulation using single pulses or theta burst stimulation. The resulting population spike is modulated by compounds acting at the central nervous system or other preparations directly or as ex vivo approach. In this case the effect of the special extract was tested in vitro the next day after repetitive in vitro administration. Conventional recording technique in the in vitro hippocampus slice revealed an increase of the population spike in the presence of single stimuli and theta burst stimuli resulting in increased long-term potentiation. This effect was tried to modulate by several glutamate receptor antagonists, among them compounds targeting at the ionic NMDA receptor (CGS19755), AMPA receptor (NBQX), Kainate receptor (UBP301) and targeting at three metabotropic glutamate receptors (mGluR I (YM298198), mGluRII ((RS)-APICA)) and mGluRIII (MSOP). Only NBQX was able to prevent the action of the Sideritis scardica extract. Since the AMPA receptor has been related to cognition in several reports in the literature, it is concluded from this result that the positive action of Sideritis scardica extract on brain function involves a modulation of AMPA receptor dependent neurotransmission.
Molecular alignment using circularly polarized laser pulses
C T L Smeenk,P B Corkum
Physics , 2013, DOI: 10.1088/0953-4075/46/20/201001
Abstract: We show that circularly polarized femtosecond laser pulses produce field-free alignment in linear and planar molecules. We study the rotational wavepacket evolution of O$_2$ and benzene created by circularly polarized light. For benzene, we align the molecular plane to the plane of polarization. For O$_2$, we demonstrate that circular polarization yields a net alignment along the laser propagation axis at certain phases of the evolution. Circular polarization gives us the ability to control alignment of linear molecules outside the plane of polarization, providing new capabilities for molecular imaging.
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