@article{ThierbachSchulzVoigtetal.2004,
  author    = {Thierbach, Rene and Schulz, Tim Julius and Voigt, Aanja and Drewes, Gunnar and Isken, F. and Pfeiffer, Andreas F. H. and Ristow, Michael and Steinberg, Pablo},
  title     = {Targeted disruption of frataxin in hepatocytes causes spontaneous neoplasia accompanied by increased ROS formation},
  issn      = {0028-1298},
  year      = {2004},
  language  = {en}
}
@article{TeubnerLangheinrichSeideletal.2004,
  author    = {Teubner, Wera and Langheinrich, C. and Seidel, Albrecht and Steinberg, Pablo},
  title     = {Inhibition of p53 transactivation activity does not promote mutagen-induced transformation of IEC-18},
  issn      = {0028-1298},
  year      = {2004},
  language  = {en}
}
@article{SzantoBenkoSzatmarietal.2004,
  author    = {Szanto, Attila and Benko, Szilvia and Szatmari, Istv{\´a}n and Balint, Balint L. and Furtos, Ibolya and Ruehl, Ralph and Molnar, Sandor and Csiba, Laszlo and Garuti, Rita and Calandra, Sebastiano and Larsson, Hanna and Diczfalusy, Ulf and Nagy, Laszlo},
  title     = {Transcriptional regulation of human CYP27 integrates retinoid, peroxisome proliferator-activated receptor, and liver X receptor signaling in macrophages},
  issn      = {0270-7306},
  year      = {2004},
  abstract  = {Cholesterol uptake and efflux are key metabolic processes associated with macrophage physiology and atherosclerosis. Peroxisome proliferator-activated receptor gamma (PPARgamma) and liver X receptor alpha (LXRalpha) have been linked to the regulation of these processes. It remains to be identified how activation of these receptors is connected and regulated by endogenous lipid molecules. We identified CYP27, a p450 enzyme, as a link between retinoid, PPARgamma, and LXR signaling. We show that the human CYP27 gene is under coupled regulation by retinoids and ligands of PPARs via a PPAR-retinoic acid receptor response element in its promoter. Induction of the enzyme's expression results in an increased level of 27-hydroxycholesterol and upregulation of LXR-mediated processes. Upregulated CYP27 activity also leads to LXR-independent elimination of CYP27 metabolites as an alternative means of cholesterol efflux. Moreover, human macrophage-rich atherosclerotic lesions have an increased level of retinoid-, PPARgamma-, and LXR- regulated gene expression and also enhanced CYP27 levels. Our findings suggest that nuclear receptor-regulated CYP27 expression is likely to be a key integrator of retinoic acid receptor-PPARgamma-LXR signaling, relying on natural ligands and contributing to lipid metabolism in macrophages},
  language  = {en}
}
@article{SchweigertWirthRaila2004,
  author    = {Schweigert, Florian J. and Wirth, Kerstin and Raila, Jens},
  title     = {Characterization of the microheterogeneity of transthyretin in plasma and urine using SELDI-TOF-MS immunoassay},
  year      = {2004},
  language  = {en}
}
@article{SchweigertRailaSehoulietal.2004,
  author    = {Schweigert, Florian J. and Raila, Jens and Sehouli, Jalid and B{\"u}scher, Ulrich},
  title     = {Accumulation of Selected Carotenoids, alpha-tocopherol and Retinol in Human Ovarian Carcinoma Ascitic Fluid},
  issn      = {1421-9697},
  year      = {2004},
  abstract  = {Background: Patients with severe forms of cancer are reported to have reduced concentrations of micronutrients in plasma due to the chronic reduction of food intake and an increased metabolism of these components. The purpose of this study was to evaluate if an accumulation of carotenoids, alpha-tocopherol and retinol in malignant ascitic fluid in women with ovarian cancer might contribute to a loss of these components from plasma. Methods: Blood and ascitic fluid samples obtained from 21 women with ovarian carcinomas and 17 healthy controls were analyzed for retinol, retinol- binding protein (RBP), alpha-tocopherol and carotenoids. Results: Plasma concentrations of all micronutrients were lower in cancer patients compared to controls. Ascitic fluid concentration of all investigated components was comparable (73- 110\%) to plasma. While the mean concentration of retinol in malignant ascites represented 73\% of that in plasma, the concentration of RBP was less than 10\% resulting in an increased mean molar ratio of retinol to RBP from 1.18 to 10.5. Conclusions: The results suggest that lower plasma concentrations of micronutrients in women suffering from ovarian carcinoma are not only caused by a cachexia-induced decrease of food intake and a higher rate of metabolic utilization, but also by a substantial yet not considered transfer from plasma into ascitic fluid possibly associated with plasma lipoproteins. This raises questions with regard to the protective function of these plasma components in ascitic fluid, the consequences of paracentesis on an additional supplementation and finally the possibility to use one or a combination of these components as an additional marker to discriminate between benign and malignant ascites. Copyright (C) 2004 S. Karger AG, Basel},
  language  = {en}
}
@article{SchweigertBatheChenetal.2004,
  author    = {Schweigert, Florian J. and Bathe, Katharina and Chen, Frank and B{\"u}scher, Ulrich and Dudenhausen, Joachim W.},
  title     = {Effect of the stage of lactation in humans on carotenoid levels in milk, blood plasma and plasma lipoprotein fractions},
  year      = {2004},
  abstract  = {In mammals the composition of milk changes during early lactation, with a rapid decline of fat-soluble vitamins and a continuous increase in total lipids. The mechanisms underlying this phenomenon are not well understood, but might involve selective mechanisms related to mammary uptake or secretion into the milk. Since carotenoids are specifically distributed among the lipoprotein fractions in plasma, the simultaneous determination of carotenoids in plasma, lipoprotein fractions and milk might offer an opportunity to gain insight into this phenomenon. In 21 healthy mothers carotenoids in plasma and lipoprotein fractions were investigated at day 2 and 19 and milk on day 4 and 19 after delivery. Plasma levels of alpha-tocopherol and cholesterol as well as lutein, zeaxanthin and cryptoxanthin were significantly lower later in lactation (day 19) than shortly after birth (P < 0.01). The stage of lactation had no effect on the distribution of carotenoids and -tocopherol among the plasma lipoprotein fractions. In milk, triacylglycerol increased (P < 0.01). In contrast, levels of carotenoids, alpha- tocopherol and vitamin A were highest in colostrum and declined (P < 0.01). Because the magnitude of decrease was not the same in all carotenoids, the carotenoid pattern changed substantially. In colostrum the carotenoid pattern resembled those of plasma and the low- density lipoprotein fraction. In mature milk it was similar to the pattern found in the high density lipoprotein fraction. Based on these observations a selective mechanism might be responsible for the transfer of these components in milk involving different lipoprotein fractions at specific times of lactation},
  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{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{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{RoetzlerRomerBudzinskietal.2004,
  author    = {R{\"o}tzler, Jochen and Romer, R. L. and Budzinski, Hubertus and Oberh{\"a}nsli, Roland},
  title     = {Ultrahigh-temperature high-pressure granulites from Tirschheim, Saxon Granulite Massif, Germany : P-T-t path and geotectonic implications},
  issn      = {0935-1221},
  year      = {2004},
  abstract  = {The Saxon granulites, the type granulite locality, were deeply buried, extremely heated and then rapidly exhumed during the Variscan Orogeny; thus their evolution differs from many granulites elsewhere. The peak-metamorphic assemblages of layered felsic-mafic granulites from a 500 m deep borehole consist of garnet, kyanite, rutile, ternary feldspar and quartz in felsic granulite, and garnet, omphacite, titanite, ternary feldspar and quartz in mafic granulite. A minimum temperature of 1000-1020degreesC, calculated from reintegrated hypersolvus feldspar in felsic and mafic granulites, is consistent with the highest temperature estimates from garnet-clinopyroxene equilibria. Various equilibria in felsic and mafic granulites record a peak pressure of about 23 kbar. Diffusion zoning and local homogenisation of minerals reflect near-isothermal decompression that preceded cooling and partial hydration at medium- to low-pressure. U-Pb dating of titanite yields an age of peak metamorphism at 340.7+/-0.8 Ma (2sigma). However, chemical inheritance from precursor rutile and post-peak Pb loss are also evident, suggesting a protolith age of 499+/-2 Ma (2sigma) and partial resetting down to an age of 333+/-2 Ma (2sigma). Rb-Sr mica ages of 333.2+/-3.3 Ma (2sigma) are interpreted as dating cooling through about 620degreesC. Hence the Saxon granulites were exhumed to the upper crust during the short period of 6-11 Ma, which corresponds to average exhumation and cooling rates of 10 mm/year and 50degreesC/Ma, respectively. Such rapid exhumation is inconsistent with recent numerical models that assume foreland- directed transport of the Saxon granulites in the lower crust followed by extensional unroofing. Instead, high-pressure rocks of the Saxon Granulite Massif and the nearby Erzgebirge experienced a buoyant rise to the middle crust and subsequent juxtaposition with structurally higher units along a series of medium- to low-pressure detachment faults},
  language  = {en}
}
@article{RohnRawelKroll2004,
  author    = {Rohn, Sascha and Rawel, Harshadrai Manilal and Kroll, J{\"u}rgen},
  title     = {Antioxidant activity of protein-bound quercetin},
  year      = {2004},
  abstract  = {Bovine serum albumin (BSA) was derivatized by covalent attachment of different amounts of quercetin (ratios of BSA : quercetin were 20:1, 10:1, 7:1, 5:1, 2:1 (w/w)). The antioxidant activity of the protein-phenol derivatives was investigated using a modified TEAC assay. The results show that the covalent attachment of quercetin to BSA decreases the total antioxidant activity in comparison to an equivalent amount of free quercetin depending on the degree of derivatization. The derivative with the highest amount of covalently bound quercetin (2:1 derivative) showed an antioxidant activity of only 79\% compared to an equivalent amount of free quercetin. After the enzymatic proteolysis of the BSA quercetin derivatives with trypsin, the total antioxidant activity of the degradation products increases in comparison to the respective undigested derivatives, but does not reach the activity of an equivalent amount of free quercetin. Even after 240 minutes of tryptic degradation there is still a lack in antioxidant activity (for the 7:1 derivative nearly 33\%) as compared to free quercetin.},
  language  = {en}
}
@article{RawelRantersRohnetal.2004,
  author    = {Rawel, Harshadrai Manilal and Ranters, Holger and Rohn, Sascha and Kroll, J{\"u}rgen},
  title     = {Assessment of the reactivity of selected isoflavones against proteins in comparison to quercetin},
  year      = {2004},
  abstract  = {Selected isoflavones (genistein, daidzein, formononetin, prunetin, biochanin A and two synthetic isoflavones) were allowed to interact with soy and whey proteins. The reaction products were analyzed in terms of covalent binding at the nucleophilic side chains of proteins. Changes in molecular properties of the proteins derivatives were documented by SDS-PAGE, IEF and SELDI-TOF-MS. The structural changes induced were studied using circular dichroism (CD). The in vitro digestibility was assessed with trypsin. The results show that the occurrence of the catechol moiety, i.e. the two adjacent (ortho) aromatic hydroxyl groups on ring B of the flavonoid structural skeleton appears to be perquisite condition for covalent binding to proteins. The catechol moiety on ring A was less reactive. Its absence lead to a slight or no significant reaction, although non-covalent interactions may still be possible even when lacking this structural element. A comparison of the data is also made with quercetin representing the flavonols.},
  language  = {en}
}
@article{RailaWirthChenetal.2004,
  author    = {Raila, Jens and Wirth, Kerstin and Chen, Frank and B{\"u}scer, Ulrich and Dudenhausen, Joachim W. and Schweigert, Florian J.},
  title     = {Excretion of vitamin A in urine of women during Normal pregnancy and pregnancy complications},
  issn      = {0250-6807},
  year      = {2004},
  abstract  = {Background/Aims: The renal function, including the excretion of low-molecular-weight proteins, changes during pregnancy and may cause a urinary excretion of retinol-binding protein (RBP). Whether it is accompanied by a substantial loss of vitamin A ( retinol) has not been established yet. We therefore determined the excretion of retinol and RBP in urine of pregnant women. Methods: The study involved analyses of urine samples from 40 healthy pregnant women and 29 women with pregnancy complications during the third trimester. Analyses of plasma and urine of 7 healthy women and 5 women with pregnancy complications were also carried out 6 weeks antepartum, at time of delivery and 1 week postpartum. Results: Urinary retinol was higher in women who suffered from pregnancy disorders with an influence on maternal metabolism ( p < 0.01). RBP was excreted at substantial concentrations in the urine of all 69 women, but there were no differences between the groups. Women with a concomitant excretion of retinol had higher levels of urinary RBP than those without a retinol excretion ( p < 0.05). Differences in plasma retinol and RBP were not significant. Conclusion: The excretion of urinary retinol may increase significantly during pregnancy complications, which needs further clarification to which extent this condition may negatively affect the vitamin A status in such women. Copyright (C) 2004 S. Karger AG, Basel},
  language  = {en}
}
@article{RailaStohrerForterreetal.2004,
  author    = {Raila, Jens and Stohrer, M. and Forterre, Simone and Stangassinger, M. and Schweigert, Florian J.},
  title     = {Effect of exercise on the mobilization of retinol and retinyl esters in plasma of sled dogs},
  year      = {2004},
  abstract  = {Fasting dogs do transport vitamin A (VA) in plasma not only as retinol but predominantly as retinyl esters. Contrary to retinol, nothing is known concerning the effects of athletic performance on plasma retinyl ester concentrations. The aim of this study was therefore to examine whether physical stress because of exercise and modification of the oxidative stress by supplementation of alpha-tocopherol influences the concentrations of retinol and retinyl esters in plasma of sled dogs. The study was carried out on 41 trained adult sled dogs, which were randomly assigned into two groups. One group (19 dogs) was daily substituted with 50 mg DL-alpha-tocopheryl acetate per kilogram body weight and the control group (22 dogs) was maintained on a basal diet during 3 months prior to exercise. The plasma concentrations of retinol, retinyl esters, alpha-tocopherol and triglycerides were measured immediately before, directly after and 24 h after exercise. The supplementation of alpha-tocopheryl acetate had no effect on plasma retinol and retinyl ester concentrations at any measurement time point. However, retinyl ester levels doubled in the non- supplemented group immediately after the race (p < 0.001), whereas in the supplemented group similar high levels were observed not until 24 h post-racing (p < 0.001). The high levels of retinyl esters were paralleled to some extent by an increase in plasma triglyceride concentrations, which were significantly higher 24 h post-racing than immediately before (p < 0.001) and after exercise (p < 0.001) in both groups. The increase in retinyl ester concentrations might be indicative of their mobilization from liver and adipose tissue. Whether plasma retinyl esters can be used as an indicator for the extent of nutrient mobilization during and post-exercise in sled dogs remains to be elucidated},
  language  = {en}
}
@article{Pueschel2004,
  author    = {P{\"u}schel, Gerhard Paul},
  title     = {Control of hepatocyte metabolism by sympathetic and parasympathetic hepatic nerves},
  year      = {2004},
  abstract  = {More than any other organ, the liver contributes to maintaining metabolic equilibrium of the body, most importantly of glucose homeostasis. It can store or release large quantities of glucose according to changing demands. This homeostasis is controlled by circulating hormones and direct innervation of the liver by autonomous hepatic nerves. Sympathetic hepatic nerves can increase hepatic glucose output; they appear, however, to contribute little to the stimulation of hepatic glucose output under physiological conditions. Parasympathetic hepatic nerves potentiate the insulin-dependent hepatic glucose extraction when a portal glucose sensor detects prandial glucose delivery from the gut. In addition, they might coordinate the hepatic and extrahepatic glucose utilization to prevent hypoglycemia and, at the same time, warrant efficient disposal of excess glucose.},
  language  = {en}
}
@article{PatheNeuschaeferRubeNeuschaeferRubePueschel2004,
  author    = {Pathe-Neusch{\"a}fer-Rube, Andrea and Neusch{\"a}fer-Rube, Frank and P{\"u}schel, Gerhard Paul},
  title     = {G protein coupling control by the ERC-motif in the proximal part of the second intracellular loop and the C- terminal domain of the human prostaglandin F-2A receptor (FP receptor)},
  issn      = {0028-1298},
  year      = {2004},
  language  = {en}
}
@article{NeuschaeferRubeHermosillaRehwaldetal.2004,
  author    = {Neusch{\"a}fer-Rube, Frank and Hermosilla, Ricardo and Rehwald, Matthias and Ronnstrand, Lars and Sch{\"u}lein, Ralf and Wernstedt, Christer and P{\"u}schel, Gerhard Paul},
  title     = {Identification of a Ser/Thr cluster in the C-terminal domain of the human prostaglandin receptor EP4 that is essential for agonist-induced beta-arrestin1 recruitment but differs from the apparent principal phosphorylation site},
  year      = {2004},
  abstract  = {hEP4-R (human prostaglandin E2 receptor, subtype EP4) is a G(s)-linked heterotrimeric GPCR (G-protein-coupled receptor). It undergoes agonist-induced desensitization and internalization that depend on the presence of its C- terminal domain. Desensitization and internalization of GPCRs are often linked to agonist-induced beta-arrestin complex formation, which is stabilized by phosphorylation. Subsequently beta-arrestin uncouples the receptor from its G-protein and links it to the endocytotic machinery. The C-terminal domain of hEP4-R contains 38 Ser/Thr residues that represent potential phosphorylation sites. The present study aimed to analyse the relevance of these Ser/Thr residues for agonist- induced phosphorylation, interaction with beta-arrestin and internalization. In response to agonist treatment, hEP4-R was phosphorylated. By analysis of proteolytic phosphopeptides of the wild-type receptor and mutants in which groups of Ser/Thr residues had been replaced by Ala, the principal phosphorylation site was mapped to a Ser/Thr-containing region comprising residues 370-382, the presence of which was necessary and sufficient to obtain full agonist-induced phosphorylation. A cluster of Ser/Thr residues (Ser-389-Ser-390-Thr-391-Ser-392) distal to this site, but not the principal phosphorylation site, was essential to allow agonist-induced recruitment of beta-arrestin1. However, phosphorylation greatly enhanced the stability of the beta-arrestin1-receptor complexes. For maximal agonist-induced internalization, phosphorylation of the principal phosphorylation site was not required, but both beta-arrestin1 recruitment and the presence of Ser/Thr residues in the distal half of the C-terminal domain were necessary.},
  language  = {en}
}
@article{NeuschaeferRubeHermosillaKunaetal.2004,
  author    = {Neusch{\"a}fer-Rube, Frank and Hermosilla, Ricardo and Kuna, Manuela and Pathe-Neuschaefer-Rube, Andrea and P{\"u}schel, Gerhard Paul},
  title     = {Agonist-induced desensitization of rat prostaglandin EP3 receptor isoforms},
  issn      = {0028-1298},
  year      = {2004},
  language  = {en}
}
@article{LoehrkeVierguthKanitzetal.2004,
  author    = {L{\"o}hrke, B. and Vierguth, T. and Kanitz, W. and G{\"o}llnitz, K. and Becker, F. and Hurtienne, Andrea and Schweigert, Florian J.},
  title     = {High milk yield in dairy cows associated with oxidant stress},
  issn      = {1328-925X},
  year      = {2004},
  language  = {en}
}
@article{KuehnelSteinbergScholtka2004,
  author    = {K{\"u}hnel, Dana and Steinberg, Pablo and Scholtka, Bettina},
  title     = {A human-relevant dose of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PHIP) can induce precancerous lesions in rat intestine after 6 months of exposure},
  issn      = {0028-1298},
  year      = {2004},
  language  = {en}
}