TY - BOOK A1 - Rühl, Ralph A1 - Garcia, Ada A1 - Herz, U. A1 - Schweigert, Florian J. A1 - Renz, H. T1 - Postnataler Einfluss von Retinoiden auf die Ontogenese des Immunsystems der Maus Y1 - 2001 ER - TY - JOUR A1 - Rühl, Ralph A1 - Sass, Jörn Oliver A1 - Nau, Heinz A1 - Klug, Stephan T1 - Effects of all-trans-retinoic acid and all-trans-retinoyl glucuronide in two in vitro systems of distinct biological complexity Y1 - 2001 ER - TY - BOOK A1 - Schmiedeberg, Kristin A1 - Rühl, Ralph A1 - Schweigert, Florian J. A1 - Meyerhof, Wolfgang A1 - Krautwurst, Dietmar T1 - Einfluss von ernährungs- und pharmakoligisch relevanten Vitamin-A-Derivaten auf das Geruchssystem der Maus Y1 - 2001 ER - TY - JOUR A1 - Elmazar, Mohamed M. A. A1 - Rühl, Ralph A1 - Nau, Heinz T1 - Synergistic Teratogenic Effects Induced by Retinoids in Mice by Coadministration of a RARa- or RARy-Selective Agonist with a RXR-Selective Agonist Y1 - 2001 ER - TY - JOUR A1 - Rühl, Ralph A1 - Thiel, Renate A1 - Lacker, Tanja Silke A1 - Srohschein, Sabine A1 - Albert, Klaus A1 - Nau, Heinz T1 - Synthesis, high-performance liquid chromatography-nuclear magnetic resonance characterization and pharmacokinetics in mice of CD271 glucuronide Y1 - 2001 ER - TY - JOUR A1 - Rühl, Ralph A1 - Plum, Claudia A1 - Elmazar, Mohamed M. A. A1 - Nau, Heinz T1 - Embryonic Subcellular Distribution of 13-cis- and All-trans-Retinoic Acid Indicates Differential Cytosolic/ Nuclear Localization Y1 - 2001 ER - TY - JOUR A1 - Garcia, Ada A1 - Rühl, Ralph A1 - Herz, U. A1 - Koebnick, Corinna A1 - Schweigert, Florian J. A1 - Worm, Margitta T1 - Retinoid- and carotenoid-enriched diets influence the ontogenesis of the immune system in mice Y1 - 2003 ER - TY - JOUR A1 - Rühl, Ralph A1 - Schweigert, Florian J. T1 - Automated solid-phase extraction and liquid chromatographic method for retinoid determination in biological samples N2 - In this study, a method for partly automated sample preparation and fully automated solid-phase extraction method for plasma, kidney and liver samples for various retinoids like all-trans-4-oxo-retinoic acid, 13-cis-4-oxo- retinoic acid, 13-cis-retinoic acid, 9-cis-retinoic acid, all-trans-retinoic acid, retinol and retinyl palmitate was established. Plasma, embryo-, kidney-and liver-homogenates were automatically mixed and extracted on multiple usage solid-phase (C2) extraction cartridges immediately before HPLC analysis. Automated cleaning, preconditioning and incorporation of the loaded cartridge to fully automated HPLC separation and quantification of the various retinoids in a single HPLC run was established. The recovery of the retinoids was generally between 80 and 90%. Intra-day repeatability was <11.7%. As little as 1.2 ng/ml could be quantified in lipid-mixture standard samples. This method allows a highly automated sample preparation and a fully automated solid-phase extraction with good selectivity for the study of endogenous retinoids and retinoids after nutritional supplementations and pharmacological applications in several biological samples. (C) 2003 Elsevier B.V. All rights reserved Y1 - 2003 ER - TY - JOUR A1 - Rühl, Ralph A1 - Garcia, Ada A1 - Schweigert, Florian J. A1 - Worm, Margitta T1 - Modulation of cytokine production by low and high retinoid diet in ovalbumin-sensitized mice N2 - Retinoids modulate many physiological processes such as the differentiation and growth of different cell types. including cells from the immune system. We have previously shown that retinoids modulate IgE production in vitro and in vivo. In the present study we investigated the effects of retinoids in non-sensitized and ovalbumin-sensitized mice that were fed for 11 weeks with three different vitamin A (VA) diets: a) VA-deficiency diet, b) base diet, and c) base diet supplemented with 0.5% all-trans-retinoic acid (ATRA). Phorbol-myristate-acetate (PMA)/ionomycin-stimulated SMC (splenic mononuclear cells) from mice fed with ATRA and the vitamin A-deficient diet group showed increased interleukin-4 (IL-4) responses in non-sensitized mice. After ovalbumin sensitization in the VA-deficient and the ATRA supplementation diet groups, no significant effects on IL-4 production were observed. By contrast, gamma interferon (IFN-gamma production from PMA/ionomycin-stimulated SMC was enhanced in the VA-deficient diet group in ovalbumin-sensitized mice, and also in non-sensitized mice compared to the base and the ATRA-supplemented diet group. The data indicate that VA and retinoid content in a diet influences the cytokine response in non-sensitized and also ovalbumin-sensitized mice. Therefore these molecules may serve as active modulators of cytokine production in vivo that are responsible for the induction and persistence of atopic diseases Y1 - 2004 ER - TY - JOUR A1 - Rühl, Ralph A1 - Sczech, Ronny A1 - Landes, Nico A1 - Pfluger, Paul Thomas A1 - Kluth, Dirk A1 - Schweigert, Florian J. T1 - Carotenoids and their metabolites are naturally occurring activators of gene expression via the pregnane X receptor N2 - Carotenoids are important micronutrients in the human diet and are present in human serum at micromolar concentrations. In addition to their antioxidant potential, carotenoids obtain physiologically relevant properties such as influencing cellular signal pathways, gene expression or induction of detoxifying enzymes. In this study, we determined the transactivation of PXR by cotransfection with the full-length receptor and a PXR-responsive reporter gene. Carotenoids and retinol revealed a 5-6-fold reporter gene activity in HepG2 cells in comparison to a 7-fold induction by the well known PXR agonist rifampicin whereas apo-carotenals and lycopene exerted less or no activation potential. The inductive efficacy was hereby concentration-dependent. In addition, carotenoid or retinol mediated gene expression of PXR responsive genes like CYP3A4/CYP3A7, CYP3A5, MDR-1 and MRP-2 has been determined in HepG2 cells by RT- PCR with upregulative properties of beta-carotene or retinol being comparable or even higher than that of rifampicin. In conclusion, PXR-mediated upregulation of CYP3A4/CYP3A7 and CYP3A5 as well as MDR1 and MRP2 by carotenoids points to a potential interference on the metabolism of xenobiotic and endogenous relevant compounds Y1 - 2004 ER -