Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Type of Medium
Language
Year
  • 1
    Language: English
    In: Biophysical Journal, 07 May 2013, Vol.104(9), pp.2089-2097
    Description: Fluorescence recovery after photobleaching (FRAP) is a widespread technique used to determine intracellular reaction and diffusion parameters. In recent years, due to technical advances and an increasing number of mathematical models for analysis, there was a resurging interest in FRAP applications. However, care has to be taken when inverting parameters from such data. We study potential influences on FRAP acquisition and analysis like initial fluorescence distribution, membrane passage, and geometrical aspects. Monte Carlo simulations are employed for the investigation of reaction-diffusion processes to additionally include cases in which no analytical description is available. To assess the importance of influencing factors we apply a sensitivity method based on elementary effects providing an estimate for the global parameter space. The combination of simulations and sensitivity measure helps us to predict ranges of parameters used in acquisition and analysis for which a reliably inversion of reaction-diffusion parameters is possible. Using this approach, we show that FRAP data are highly susceptible to misinterpretation. However, by identifying the parameters of susceptibility, our analysis provides the means for taking measures to significantly improve FRAP data interpretation and analysis.
    Keywords: Biology
    ISSN: 0006-3495
    E-ISSN: 1542-0086
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    In: Nature, 2011, Vol.478(7368), p.197
    Description: Activation of the aryl hydrocarbon receptor (AHR) by environmental xenobiotic toxic chemicals, for instance 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), has been implicated in a variety of cellular processes such as embryogenesis, transformation, tumorigenesis and inflammation. But the identity of an endogenous ligand activating the AHR under physiological conditions in the absence of environmental toxic chemicals is still unknown. Here we identify the tryptophan (Trp) catabolite kynurenine (Kyn) as an endogenous ligand of the human AHR that is constitutively generated by human tumour cells via tryptophan-2,3-dioxygenase (TDO), a liver- and neuron-derived Trp-degrading enzyme not yet implicated in cancer biology. TDO-derived Kyn suppresses antitumour immune responses and promotes tumour-cell survival and motility through the AHR in an autocrine/paracrine fashion. The TDO-AHR pathway is active in human brain tumours and is associated with malignant progression and poor survival. Because Kyn is produced during cancer progression and inflammation in the local microenvironment in amounts sufficient for activating the human AHR, these results provide evidence for a previously unidentified pathophysiological function of the AHR with profound implications for cancer and immune biology.
    Keywords: Sciences (General) ; Physics;
    ISSN: 0028-0836
    E-ISSN: 14764687
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Biophysical Journal, 2011, Vol.100(5), pp.1178-1188
    Description: At present, fluorescence recovery after photobleaching (FRAP) data are interpreted using various types of reaction-diffusion (RD) models: the model type is usually fixed first, and corresponding model parameters are inferred subsequently. In this article, we describe what we believe to be a novel approach for RD modeling without using any assumptions of model type or parameters. To the best of our knowledge, this is the first attempt to address both model-type and parameter uncertainties in inverting FRAP data. We start from the most general RD model, which accounts for a flexible number of molecular fractions, all mobile, with different diffusion coefficients. The maximal number of possible binding partners is identified and optimal parameter sets for these models are determined in a global search of the parameter-space using the Simulated Annealing strategy. The numerical performance of the described techniques was assessed using artificial and experimental FRAP data. Our general RD model outperformed the standard RD models used previously in modeling FRAP measurements and showed that intracellular molecular mobility can only be described adequately by allowing for multiple RD processes. Therefore, it is important to search not only for the optimal parameter set but also for the optimal model type.
    Keywords: Biology
    ISSN: 0006-3495
    E-ISSN: 1542-0086
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Biophysical journal, 2011, Vol.100(5), pp.1178-1188
    Description: At present, fluorescence recovery after photobleaching (FRAP) data are interpreted using various types of reaction-diffusion (RD) models: the model type is usually fixed first, and corresponding model parameters are inferred subsequently. In this article, we describe what we believe to be a novel approach for RD modeling without using any assumptions of model type or parameters. To the best of our knowledge, this is the first attempt to address both model-type and parameter uncertainties in inverting FRAP data. We start from the most general RD model, which accounts for a flexible number of molecular fractions, all mobile, with different diffusion coefficients. The maximal number of possible binding partners is identified and optimal parameter sets for these models are determined in a global search of the parameter-space using the Simulated Annealing strategy. The numerical performance of the described techniques was assessed using artificial and experimental FRAP data. Our general RD model outperformed the standard RD models used previously in modeling FRAP measurements and showed that intracellular molecular mobility can only be described adequately by allowing for multiple RD processes. Therefore, it is important to search not only for the optimal parameter set but also for the optimal model type. ; p. 1178-1188.
    Keywords: Models ; Photobleaching ; Fluorescence ; Diffusivity
    ISSN: 0006-3495
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: BMC Public Health, 01 October 2018, Vol.18(1), pp.1-10
    Description: Abstract Background Maternal perceived stress has been discussed to contribute to the development of childhood overweight. Our aim was to investigate the longitudinal relationship of early maternal perceived stress and BMI z-scores in preschool...
    Keywords: Stress Dimensions ; Perceived Stress ; Weight Development ; Stressor ; Infant ; Preschool Children ; Public Health
    E-ISSN: 1471-2458
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    In: Kidney International, 2010, Vol.78(4), p.425
    Keywords: Acidosis–Diagnosis ; Female–Etiology ; Humans–Metabolism ; Middle Aged–Metabolism ; Recurrence–Metabolism ; Renal Dialysis–Metabolism ; Tartrates–Metabolism ; Tartrates ; Tartaric Acid;
    ISSN: 0085-2538
    E-ISSN: 15231755
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: The Journal of Allergy and Clinical Immunology, August 2017, Vol.140(2), pp.603-605
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jaci.2017.01.034 Byline: Marcus Winter (a), Loreen Thurmann (a), Zuguang Gu (b)(c), Gerrit Schuurmann (d)(e), Gunda Herberth (a), Denise Hinz (a)(f), Martin von Bergen (g)(h), Hauke Harms (i), Sven Olek (j), Stefan Roder (a), Michael Borte (k), Roland Eils (b)(c)(l)(m), Irina Lehmann (a), Saskia Trump (a) Author Affiliation: (a) Department of Environmental Immunology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany (b) Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany (c) Heidelberg Center for Personalized Oncology (DKFZ-HIPO), Heidelberg, Germany (d) Department of Ecological Chemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany (e) Technical University Bergakademie Freiberg, Freiberg, Germany (f) La Jolla Institute for Allergy and Immunology, La Jolla, Calif (g) Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany (h) Faculty of Biosciences, Pharmacy and Psychology, Department of Biochemistry, University of Leipzig, Leipzig, Germany (i) Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany (j) Epiontis GmbH, Berlin, Germany (k) Municipal Hospital "St Georg" Children's Hospital, Leipzig, Germany (l) Institute of Pharmacy and Molecular Biotechnology (IPMB), and BioQuant Center, University of Heidelberg, Heidelberg, Germany (m) Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany Article Note: (footnote) M.W. was supported by the "Helmholtz Impulse and Networking Fund" through the "Helmholtz Interdisciplinary Graduate School for Environmental Research (HIGRADE)." Further support for S.T. came from the Helmholtz Initiative for Personalized Medicine (iMed)., Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest.
    Keywords: Medicine
    ISSN: 0091-6749
    E-ISSN: 1097-6825
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Toxicology, 2011, Vol.284(1), pp.34-41
    Description: T-2 toxin (T-2) is a secondary metabolite produced by various mould species of the genus and a common contaminant detectable in staple foods of cereal origin. In the present study the impact of this mycotoxin on the inflammatory response of the intestinal epithelial cell line Caco-2 was examined by measuring interleukin (IL)-8 secretion. A T-2 concentration dependent IL-8 up-regulation was detected in IL-1β stimulated and unstimulated Caco-2 cells. To elucidate the possible underlying molecular mechanism of this conditional T-2-provoked IL-8 induction, a possible involvement of the aryl hydrocarbon receptor (AHR) and the mitogen-activated protein kinase (MAPK) pathway was investigated. Like benzo-[a]-pyrene (B[a]P), a well known AHR ligand, T-2 led to cytochrome P450 1A1 (CYP1A1) mRNA expression in Caco-2 cells, which could be inhibited by the AHR antagonist resveratrol. However, resveratrol did not influence T-2-dependent IL-8 induction. Since T-2 did not lead to AHR-translocation in stably GFP-AHR-transfected cells, an AHR dependency of T-2-triggered IL-8 induction could be excluded. But finally, up to a total inhibition of T-2-induced IL-8 was obtained using p38 inhibitors. Therefore, we conclude that p38 MAPK is responsible for mediating the inflammatory properties of the type A trichothecene T-2.
    Keywords: T-2 Toxin ; P38 Mapk ; Aryl Hydrocarbon Receptor ; Cyp1a1 ; Il-8 ; Caco-2 ; Pharmacy, Therapeutics, & Pharmacology ; Public Health
    ISSN: 0300-483X
    E-ISSN: 1879-3185
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    In: Journal of Biophotonics, May 2015, Vol.8(5), pp.361-371
    Description: This study investigates the cellular response of murine hepatoma cells to the polycyclic aromatic hydrocarbon benzo[a]pyrene (B[a]P) using two‐photon and confocal laser scanning microscopy. The intracellular distribution of B[a]P and the B[a]P/AhR complex was visualized time‐ and concentration‐dependent for up to 48 h of exposure. B[a]P was predominantly found in lipid droplets, endoplasmic reticulum and lysosomes, where B[a]P is collected and forms large aggregates. Changes in mitochondrial membrane potential and bleb formation due to high B[a]P concentrations were observed. The imaging data presented in this study provide new insights into the systemic cellular regulation following B[a]P exposure. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) This study investigates the cellular response of murine hepatoma cells to the polycyclic aromatic hydrocarbon benzo[a]pyrene (B[a]P) using two‐photon and confocal laser scanning microscopy. B[a]P was predominantly found in lipid droplets, endoplasmic reticulum and lysosomes, where B[a]P is collected and forms large aggregates. Changes in mitochondrial membrane potential and bleb formation due to high B[a]P concentrations were observed. The imaging data presented in this study provide new insights into the systemic cellular regulation following B[a]P exposure.
    Keywords: Live Cell Imaging ; Benzo[A]Pyrene ; 2‐Photon ; Confocal Microscopy
    ISSN: 1864-063X
    E-ISSN: 1864-0648
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: BMC Genomics, Oct 13, 2011, Vol.12, p.502
    Description: Background Small molecule ligands often have multiple effects on the transcriptional program of a cell: they trigger a receptor specific response and additional, indirect responses ("side effects"). Distinguishing those responses is important for understanding side effects of drugs and for elucidating molecular mechanisms of toxic chemicals. Results We explored this problem by exposing cells to the environmental contaminant benzo-[a]-pyrene (B[a]P). B[a]P exposure activates the aryl hydrocarbon receptor (Ahr) and causes toxic stress resulting in transcriptional changes that are not regulated through Ahr. We sought to distinguish these two types of responses based on a time course of expression changes measured after B[a]P exposure. Using Random Forest machine learning we classified 81 primary Ahr responders and 1,308 genes regulated as side effects. Subsequent weighted clustering gave further insight into the connection between expression pattern, mode of regulation, and biological function. Finally, the accuracy of the predictions was supported through extensive experimental validation. Conclusion Using a combination of machine learning followed by extensive experimental validation, we have further expanded the known catalog of genes regulated by the environmentally sensitive transcription factor Ahr. More broadly, this study presents a strategy for distinguishing receptor-dependent responses and side effects based on expression time courses.
    Keywords: Benzopyrene -- Health Aspects ; Benzopyrene -- Environmental Aspects ; Benzopyrene -- Research ; Transcription (Genetics) -- Research
    ISSN: 1471-2164
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages