TY - JOUR A1 - Hentschke, Reinhard A1 - Hager, Jonathan A1 - Hojdis, Nils T1 - Molecular Modeling Approach to the Prediction of Mechanical Properties of Silica-Reinforced Rubbers JF - Journal of Applied Polymer Science N2 - Recently, we have suggested a nanomechanical model for dissipative loss in filled elastomer networks in the context of the Payne effect. The mechanism is based on a total interfiller particle force exhibiting an intermittent loop, due to the combination of short-range repulsion and dispersion forces with a long-range elastic attraction. The sum of these forces leads, under external strain, to a spontaneous instability of “bonds” between the aggregates in a filler network and attendant energy dissipation. Here, we use molecular dynamics simulations to obtain chemically realistic forces between surface modified silica particles. The latter are combined with the above model to estimate the loss modulus and the low strain storage modulus in elastomers containing the aforementioned filler-compatibilizer systems. The model is compared to experimental dynamic moduli of silica filled rubbers. We find good agreement between the model predictions and the experiments as function of the compatibilizer's molecular structure and its bulk concentration. KW - theory and modeling KW - supramolecular structures KW - rubber KW - mechanical properties KW - elastomers Y1 - 2014 U6 - http://dx.doi.org/10.1002/app.40806 SN - 1097-4628 VL - 131 IS - 18 SP - 1 EP - 9 PB - Wiley CY - New York, NY ER - TY - JOUR A1 - Scheer, Nico A1 - Wolf, C. Roland T1 - Genetically humanized mouse models of drug metabolizing enzymes and transporters and their applications JF - Xenobiotica N2 - 1. Drug metabolizing enzymes and transporters play important roles in the absorption, metabolism, tissue distribution and excretion of various compounds and their metabolites and thus can significantly affect their efficacy and safety. Furthermore, they can be involved in drug–drug interactions which can result in adverse responses, life-threatening toxicity or impaired efficacy. Significant species differences in the interaction of compounds with drug metabolizing enzymes and transporters have been described. 2. In order to overcome the limitation of animal models in accurately predicting human responses, a large variety of mouse models humanized for drug metabolizing enzymes and to a lesser extent drug transporters have been created. 3. This review summarizes the literature describing these mouse models and their key applications in studying the role of drug metabolizing enzymes and transporters in drug bioavailability, tissue distribution, clearance and drug–drug interactions as well as in human metabolite testing and risk assessment. 4. Though such humanized mouse models have certain limitations, there is great potential for their use in basic research and for testing and development of new medicines. These limitations and future potentials will be discussed. KW - transporters KW - human metabolites KW - drug metabolising enzymes KW - drug–drug interactions KW - bioavailability Y1 - 2014 U6 - http://dx.doi.org/10.3109/00498254.2013.815831 SN - 1366-5928 VL - 44 IS - 2 SP - 96 EP - 108 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Scheer, Nico A1 - Mclaughlin, Lesley A. A1 - Rode, Anja A1 - MacLeod, Alastair Kenneth A1 - Henderson, Colin J. A1 - Wolf, Roland C. T1 - Deletion of thirty murine cytochrome P450 genes results in viable mice with compromised drug metabolism JF - Drug Metabolism and Disposition N2 - In humans, 75% of all drugs are metabolized by the cytochrome P450-dependent monooxygenase system. Enzymes encoded by the CYP2C, CYP2D, and CYP3A gene clusters account for ∼80% of this activity. There are profound species differences in the multiplicity of cytochrome P450 enzymes, and the use of mouse models to predict pathways of drug metabolism is further complicated by overlapping substrate specificity between enzymes from different gene families. To establish the role of the hepatic and extrahepatic P450 system in drug and foreign chemical disposition, drug efficacy, and toxicity, we created a unique mouse model in which 30 cytochrome P450 genes from the Cyp2c, Cyp2d, and Cyp3a gene clusters have been deleted. Remarkably, despite a wide range of putative important endogenous functions, Cyp2c/2d/3a KO mice were viable and fertile, demonstrating that these genes have evolved primarily as detoxification enzymes. Although there was no overt phenotype, detailed examination showed Cyp2c/2d/3a KO mice had a smaller body size (15%) and larger livers (20%). Changes in hepatic morphology and a decreased blood glucose (30%) were also noted. A five-drug cocktail of cytochrome P450 isozyme probe substrates were used to evaluate changes in drug pharmacokinetics; marked changes were observed in either the pharmacokinetics or metabolites formed from Cyp2c, Cyp2d, and Cyp3a substrates, whereas the metabolism of the Cyp1a substrate caffeine was unchanged. Thus, Cyp2c/2d/3a KO mice provide a powerful model to study the in vivo role of the P450 system in drug metabolism and efficacy, as well as in chemical toxicity. Y1 - 2014 U6 - http://dx.doi.org/10.1124/dmd.114.057885 SN - 1521-009X VL - 42 IS - 6 SP - 1022 EP - 1030 PB - ASPET CY - Bethesda, Md. ER - TY - JOUR A1 - Salpati, Laurent A1 - Chu, Xiaoyan A1 - Chen, Liangfu A1 - Prasad, Bhagwat A1 - Dallas, Shannon A1 - Evers, Raymond A1 - Mamaril-Fishman, Donna A1 - Geier, Ethan G. A1 - Kehler, Jonathan A1 - Kunta, Jeevan A1 - Mezler, Mario A1 - Laplanche, Loic A1 - Pang, Jodie A1 - Soars, Matthew G. A1 - Unadkat, Jashvant D. A1 - van Waterschoot, Robert A.B. A1 - Yabut, Jocelyn A1 - Schinkel, Alfred H. A1 - Scheer, Nico A1 - Rode, Anja T1 - Evaluation of organic anion transporting polypeptide 1B1 and 1B3 humanized mice as a translational model to study the pharmacokinetics of statins JF - Drug Metabolism and Disposition N2 - Organic anion transporting polypeptide (Oatp) 1a/1b knockout and OATP1B1 and -1B3 humanized mouse models are promising tools for studying the roles of these transporters in drug disposition. Detailed characterization of these models will help to better understand their utility for predicting clinical outcomes. To advance this approach, we carried out a comprehensive analysis of these mouse lines by evaluating the compensatory changes in mRNA expression, quantifying the amounts of OATP1B1 and -1B3 protein by liquid chromatography–tandem mass spectrometry, and studying the active uptake in isolated hepatocytes and the pharmacokinetics of some prototypical substrates including statins. Major outcomes from these studies were 1) mostly moderate compensatory changes in only a few genes involved in drug metabolism and disposition, 2) a robust hepatic expression of OATP1B1 and -1B3 proteins in the respective humanized mouse models, and 3) functional activities of the human transporters in hepatocytes isolated from the humanized models with several substrates tested in vitro and with pravastatin in vivo. However, the expression of OATP1B1 and -1B3 in the humanized models did not significantly alter liver or plasma concentrations of rosuvastatin and pitavastatin compared with Oatp1a/1b knockout controls under the conditions used in our studies. Hence, although the humanized OATP1B1 and -1B3 mice showed in vitro and/or in vivo functional activity with some statins, further characterization of these models is required to define their potential use and limitations in the prediction of drug disposition and drug-drug interactions in humans. Y1 - 2014 U6 - http://dx.doi.org/10.1124/dmd.114.057976 SN - 1521-009X VL - 42 IS - 8 SP - 1301 EP - 1313 PB - ASPET CY - Bethesda, Md. ER - TY - JOUR A1 - Luisier, Raphaëlle A1 - Lempiäinen, Harri A1 - Scherbichler, Nina A1 - Braeuning, Albert A1 - Geissler, Miriam A1 - Dubost, Valerie A1 - Müller, Arne A1 - Scheer, Nico A1 - Chibout, Salah-Dine A1 - Hara, Hisanori A1 - Picard, Frank A1 - Theil, Diethilde A1 - Couttet, Philippe A1 - Vitobello, Antonio A1 - Grenet, Olivier A1 - Grasl-Kraupp, Bettina A1 - Ellinger-Ziegelbauer, Heidrung A1 - Thomson, John P. A1 - Meehan, Richard R. A1 - Elcombe, Clifford R. A1 - Henderson, Colin J. A1 - Wolf, C. Roland A1 - Schwarz, Michael A1 - Moulin, Pierre A1 - Terranova, Remi A1 - Moggs, Jonathan G. T1 - Phenobarbital Induces Cell Cycle Transcriptional Responses in Mouse Liver Humanized for Constitutive Androstane and Pregnane X Receptors JF - Toxicological Sciences N2 - The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are closely related nuclear receptors involved in drug metabolism and play important roles in the mechanism of phenobarbital (PB)-induced rodent nongenotoxic hepatocarcinogenesis. Here, we have used a humanized CAR/PXR mouse model to examine potential species differences in receptor-dependent mechanisms underlying liver tissue molecular responses to PB. Early and late transcriptomic responses to sustained PB exposure were investigated in liver tissue from double knock-out CAR and PXR (CARᴷᴼ-PXRᴷᴼ), double humanized CAR and PXR (CARʰ-PXRʰ), and wild-type C57BL/6 mice. Wild-type and CARʰ-PXRʰ mouse livers exhibited temporally and quantitatively similar transcriptional responses during 91 days of PB exposure including the sustained induction of the xenobiotic response gene Cyp2b10, the Wnt signaling inhibitor Wisp1, and noncoding RNA biomarkers from the Dlk1-Dio3 locus. Transient induction of DNA replication (Hells, Mcm6, and Esco2) and mitotic genes (Ccnb2, Cdc20, and Cdk1) and the proliferation-related nuclear antigen Mki67 were observed with peak expression occurring between 1 and 7 days PB exposure. All these transcriptional responses were absent in CARᴷᴼ-PXRᴷᴼ mouse livers and largely reversible in wild-type and CARʰ-PXRʰ mouse livers following 91 days of PB exposure and a subsequent 4-week recovery period. Furthermore, PB-mediated upregulation of the noncoding RNA Meg3, which has recently been associated with cellular pluripotency, exhibited a similar dose response and perivenous hepatocyte-specific localization in both wild-type and CARʰ-PXRʰ mice. Thus, mouse livers coexpressing human CAR and PXR support both the xenobiotic metabolizing and the proliferative transcriptional responses following exposure to PB. Y1 - 2014 U6 - http://dx.doi.org/https://doi.org/10.1093/toxsci/kfu038 SN - 1094-2025 VL - 139 IS - 2 SP - 501 EP - 511 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Hoehr, Cornelia A1 - Paulßen, Elisabeth A1 - Benard, Francois A1 - Lee, Chris Jaeil A1 - Hou, Xinchi A1 - Badesso, Brian A1 - Ferguson, Simon A1 - Miao, Qing A1 - Yang, Hua A1 - Buckley, Ken A1 - Hanemaayer, Victoire A1 - Zeisler, Stefan A1 - Ruth, Thomas A1 - Celler, Anna A1 - Schaffer, Paul T1 - ⁴⁴ᶢSc production using a water target on a 13 MeV cyclotron JF - Nuclear medicine and biology N2 - Access to promising radiometals as isotopes for novel molecular imaging agents requires that they are routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for the metal of interest is necessary, both of which can introduce significant hurdles in development of less common isotopes. Herein, we describe the production of ⁴⁴Sc (t₁⸝₂ = 3.97 h, Eavg,β⁺ = 1.47 MeV, branching ratio = 94.27%) in a solution target and an automated loading system which allows a quick turn-around between different radiometallic isotopes and therefore greatly improves their availability for tracer development. Experimental yields are compared to theoretical calculations. Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.nucmedbio.2013.12.016 SN - 1872-9614 VL - 41 IS - 5 SP - 401 EP - 406 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Al-Kaidy, H. A1 - Ulber, R. A1 - Tippkötter, Nils T1 - A platform technology for the automated reaction control in magnetizable micro-fluidic droplets T2 - Biomaterials - made in bioreactors : book of abstracts, May 26 - 28, 2014, Radisson Blu Park Hotel and Conference Dentre, Radebeul, Germany Y1 - 2014 SP - 21 EP - 22 PB - DECHEMA CY - Frankfurt am Main ER - TY - PAT A1 - Al-Kaidy, Huschyar A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - Vorrichtung und Verfahren zur Bestimmung des Kontaktwinkels eines flüssigen oder mit Flüssigkeit gefüllten Körpers [Offenlegungsschrift] N2 - Die vorliegende Erfindung betrifft eine Vorrichtung und ein Verfahren zur Bestimmung des Kontaktwinkels eines flüssigen oder mit Flüssigkeit gefüllten Körpers. Dieser besteht aus einem Träger (1) und einer damit verbundenen, in einem Winkelbereich von mehr als 0° bis maximal 90° neigbaren Ebene (8) mit einer darin ausgebildeten Abrollbahn (9) für den flüssigen oder mit Flüssigkeit gefüllten Körper. An der Ebene (8) sind mehrere Sensoren (11, 12) zur Erfassung der Rolldauer des Körpers entlang der Rollstrecke angeordnet. Erfindungsgemäß ist vorgesehen, dass die Einstellung des Neigungswinkels der Ebene (8) über ein Winkelmessgerät (10) erfolgt, wodurch ein Abrollwinkel erfassbar ist, bei dem der Körper in Bewegung gerät. Aus der Rolldauer, der Rollstrecke und dem Abrollwinkel wird der Kontaktwinkel des Körpers ermittelt. Y1 - 2014 PB - Deutsches Patent- und Markenamt CY - München ER - TY - JOUR A1 - Tippkötter, Nils A1 - Duwe, Anna-Maria A1 - Wiesen, Sebastian A1 - Sieker, Tim A1 - Ulber, Roland T1 - Enzymatic hydrolysis of beech wood lignocellulose at high solid contents and its utilization as substrate for the production of biobutanol and dicarboxylic acids JF - Bioresource Technology N2 - The development of a cost-effective hydrolysis for crude cellulose is an essential part of biorefinery developments. To establish such high solid hydrolysis, a new solid state reactor with static mixing is used. However, concentrations >10% (w/w) cause a rate and yield reduction of enzymatic hydrolysis. By optimizing the synergetic activity of cellulolytic enzymes at solid concentrations of 9%, 17% and 23% (w/w) of crude Organosolv cellulose, glucose concentrations of 57, 113 and 152 g L⁻¹ are reached. However, the glucose yield decreases from 0.81 to 0.72gg⁻¹ at 17% (w/w). Optimal conditions for hydrolysis scale-up under minimal enzyme addition are identified. As result, at 23% (w/w) crude cellulose the glucose yield increases from 0.29 to 0.49gg⁻¹. As proof of its applicability, biobutanol, succinic and itaconic acid are produced with the crude hydrolysate. The potential of the substrate is proven e.g. by a high butanol yield of 0.33gg⁻¹. Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.biortech.2014.06.052 VL - 167 SP - 447 EP - 455 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Al-Kaidy, Huschyar A1 - Duwe, Anna A1 - Huster, Manuel A1 - Muffler, Kai A1 - Schlegel, Christin A1 - Sieker, Tim A1 - Stadtmüller, Ralf A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - Biotechnologie und Bioverfahrenstechnik – Vom ersten Ullmanns Artikel bis hin zu aktuellen Forschungsthemen JF - Chemie Ingenieur Technik N2 - Biotechnologie und die mit ihr verbundenen technischen Prozesse prägen seit Jahrtausenden die Entwicklung der Menschheit. Ausgehend von empirischen Verfahren, insbesondere zur Herstellung von Lebensmitteln und täglichen Gebrauchsgütern, haben sich diese Disziplinen zu einem der innovativsten Zukunftsfelder entwickelt. Durch das immer detailliertere Verständnis zellulärer Vorgänge können mittlerweile Produktionsstämme gezielt optimiert werden. Im Zusammenspiel mit moderner Prozesstechnik können so eine Vielzahl von Bulk- und Feinchemikalien sowie Pharmazeutika effizient hergestellt werden. In diesem Artikel werden exemplarisch einige der aktuellen Trends vorgestellt. Y1 - 2014 U6 - http://dx.doi.org/10.1002/cite.201400083 SN - 0009-286X VL - 86 IS - 12 SP - 2215 EP - 2225 PB - Wiley-VCH CY - Weinheim ER -