@article{RuehlThielLackeretal.2001,
  author    = {R{\"u}hl, Ralph and Thiel, Renate and Lacker, Tanja Silke and Srohschein, Sabine and Albert, Klaus and Nau, Heinz},
  title     = {Synthesis, high-performance liquid chromatography-nuclear magnetic resonance characterization and pharmacokinetics in mice of CD271 glucuronide},
  year      = {2001},
  language  = {en}
}
@article{ElmazarRuehlNau2001,
  author    = {Elmazar, Mohamed M. A. and R{\"u}hl, Ralph and Nau, Heinz},
  title     = {Synergistic Teratogenic Effects Induced by Retinoids in Mice by Coadministration of a RARa- or RARy-Selective Agonist with a RXR-Selective Agonist},
  year      = {2001},
  language  = {en}
}
@article{GarciaRuehlHerzetal.2003,
  author    = {Garcia, Ada and R{\"u}hl, Ralph and Herz, U. and Koebnick, Corinna and Schweigert, Florian J. and Worm, Margitta},
  title     = {Retinoid- and carotenoid-enriched diets influence the ontogenesis of the immune system in mice},
  year      = {2003},
  language  = {en}
}
@book{RuehlGarciaHerzetal.2001,
  author    = {R{\"u}hl, Ralph and Garcia, Ada and Herz, U. and Schweigert, Florian J. and Renz, H.},
  title     = {Postnataler Einfluss von Retinoiden auf die Ontogenese des Immunsystems der Maus},
  year      = {2001},
  language  = {de}
}
@article{RuehlGarciaSchweigertetal.2004,
  author    = {R{\"u}hl, Ralph and Garcia, Ada and Schweigert, Florian J. and Worm, Margitta},
  title     = {Modulation of cytokine production by low and high retinoid diet in ovalbumin-sensitized mice},
  year      = {2004},
  abstract  = {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},
  language  = {en}
}
@article{KochBrovkinaRuehletal.2006,
  author    = {Koch, Christin and Brovkina, Lioudmila and R{\"u}hl, Ralph and Worm, Margitta},
  title     = {Immunomodulation by dietary n3-polyunsaturated fatty acids (PUFA) in vitro},
  issn      = {0091-6749},
  year      = {2006},
  language  = {en}
}
@article{RuehlHamscherGarciaetal.2004,
  author    = {R{\"u}hl, Ralph and Hamscher, Gerd and Garcia, Ada and Nau, Heinz and Schweigert, Florian J.},
  title     = {Identification of 14-hydroxy-retro-retinol and 4-hydroxy-retinol as endogenous retinoids in rats throughout neonatal development},
  issn      = {0024-3205},
  year      = {2004},
  abstract  = {14-Hydroxy-retro-retinol was previously described as an in vivo and in vitro metabolite of retinol. Furthermore, the retinoid 4-hydroxy-retinol was identified as an endogenous occurring retinoid in the amphibian organism and an in vitro metabolite of retinol. We describe in the present study that 14-hydroxy-retro-retinol and 4-hydroxy- retinol are present in normal neonatal rat serum as endogenous occurring retinoids in normal non-vitamin A supplemented mammals (rats). Both retinoids were detected in serum and liver of neonatal rats at days 3 and 11 after birth. The respective concentrations at day 11 after birth were 41.8 +/- 2.8 ng/ml (serum)/ 104 +/- 6 ng/g (liver) for 4-hydroxy- retinol and 23 +/- 4.6 ng/ml (serum)/ 285 +/- 5 ng/g (liver) for 14-hydroxy-retro-retinol. Both retinoids could not be detected in adult rat serum and liver. From our experiments important physiological functions of these retinoids during postnatal development could be postulated. (C) 2004 Elsevier Inc. All rights reserved},
  language  = {en}
}
@article{RuehlPlumElmazaretal.2001,
  author    = {R{\"u}hl, Ralph and Plum, Claudia and Elmazar, Mohamed M. A. and Nau, Heinz},
  title     = {Embryonic Subcellular Distribution of 13-cis- and All-trans-Retinoic Acid Indicates Differential Cytosolic/ Nuclear Localization},
  year      = {2001},
  language  = {en}
}
@book{SchmiedebergRuehlSchweigertetal.2001,
  author    = {Schmiedeberg, Kristin and R{\"u}hl, Ralph and Schweigert, Florian J. and Meyerhof, Wolfgang and Krautwurst, Dietmar},
  title     = {Einfluss von ern{\"a}hrungs- und pharmakoligisch relevanten Vitamin-A-Derivaten auf das Geruchssystem der Maus},
  year      = {2001},
  language  = {de}
}
@article{RuehlSassNauetal.2001,
  author    = {R{\"u}hl, Ralph and Sass, J{\"o}rn Oliver and Nau, Heinz and Klug, Stephan},
  title     = {Effects of all-trans-retinoic acid and all-trans-retinoyl glucuronide in two in vitro systems of distinct biological complexity},
  year      = {2001},
  language  = {en}
}
@article{RuehlSczechLandesetal.2004,
  author    = {R{\"u}hl, Ralph and Sczech, Ronny and Landes, Nico and Pfluger, Paul Thomas and Kluth, Dirk and Schweigert, Florian J.},
  title     = {Carotenoids and their metabolites are naturally occurring activators of gene expression via the pregnane X receptor},
  year      = {2004},
  abstract  = {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},
  language  = {en}
}
@article{RuehlSchweigert2003,
  author    = {R{\"u}hl, Ralph and Schweigert, Florian J.},
  title     = {Automated solid-phase extraction and liquid chromatographic method for retinoid determination in biological samples},
  year      = {2003},
  abstract  = {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},
  language  = {en}
}