TY - JOUR A1 - Chaykovska, Lyubov A1 - Heunisch, Fabian A1 - von Einem, Gina A1 - Alter, Markus L. A1 - Hocher, Carl-Friedrich A1 - Tsuprykov, Oleg A1 - Dschietzig, Thomas A1 - Kretschmer, Axel A1 - Hocher, Berthold T1 - Urinary Vitamin D Binding Protein and KIM-1 Are Potent New Biomarkers of Major Adverse Renal Events in Patients Undergoing Coronary Angiography JF - PLoS one N2 - Background Vitamin-D-binding protein (VDBP) is a low molecular weight protein that is filtered through the glomerulus as a 25-(OH) vitamin D 3/VDBP complex. In the normal kidney VDBP is reabsorbed and catabolized by proximal tubule epithelial cells reducing the urinary excretion to trace amounts. Acute tubular injury is expected to result in urinary VDBP loss. The purpose of our study was to explore the potential role of urinary VDBP as a biomarker of an acute renal damage. Method We included 314 patients with diabetes mellitus or mild renal impairment undergoing coronary angiography and collected blood and urine before and 24 hours after the CM application. Patients were followed for 90 days for the composite endpoint major adverse renal events (MARE: need for dialysis, doubling of serum creatinine after 90 days, unplanned emergency rehospitalization or death). Results Increased urine VDBP concentration 24 hours after contrast media exposure was predictive for dialysis need (no dialysis: 113.06 +/- 299.61ng/ml, n = 303; need for dialysis: 613.07 +/- 700.45 ng/ml, n = 11, Mean +/- SD, p < 0.001), death (no death during follow-up: 121.41 +/- 324.45 ng/ml, n = 306; death during follow-up: 522.01 +/- 521.86 ng/ml, n = 8; Mean +/- SD, p < 0.003) and MARE (no MARE: 112.08 +/- 302.00ng/ml, n = 298; MARE: 506.16 +/- 624.61 ng/ml, n = 16, Mean +/- SD, p < 0.001) during the follow-up of 90 days after contrast media exposure. Correction of urine VDBP concentrations for creatinine excretion confirmed its predictive value and was consistent with increased levels of urinary Kidney Injury Molecule1 (KIM-1) and baseline plasma creatinine in patients with above mentioned complications. The impact of urinary VDBP and KIM-1 on MARE was independent of known CIN risk factors such as anemia, preexisting renal failure, preexisting heart failure, and diabetes. Conclusions Urinary VDBP is a promising novel biomarker of major contrast induced nephropathy-associated events 90 days after contrast media exposure. Y1 - 2016 U6 - https://doi.org/10.1371/journal.pone.0145723 SN - 1932-6203 VL - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Nagl, Britta A1 - Loui, Andrea A1 - Raila, Jens A1 - Felderhoff-Mueser, Ursula A1 - Obladen, Michael A1 - Schweigert, Florian J. T1 - Urinary vitamin A excretion in very low birth weight infants N2 - Vitamin A (VA) deficiency in very low birth weight (VLBW) infants is associated with an increased risk for disorders related to kidney and lung maturation and function. VA losses through increased urinary retinol (ROH) excretion might contribute to this deficiency risk. The mechanism accounting for ROH loss in the urine has not yet been clarified. The aim of this study was to assess the excretion of ROH, retinol-binding protein 4 (RBP4) and transthyretin (TTR) in urine from VLBW infants in comparison with that in term infants in relation to kidney function. Urine specimens were collected from 15 VLBW infants (birth weight < 1,500 g) as well as from 20 term infants during the first 2 days after birth. ROH in urine was detectable in 14 of the 15 VLBW infants at a median concentration of 234 nmol/g creatinine. In the group of term infants, 17 of the 20 excreted ROH, but at an approximately five-times lower concentration (P<0.001). Excretion of RBP4 and TTR was also much higher in VLBW infants (both P<0.001). The urinary ROH excretion in VLBW infants may be related to the impaired tubular handling of its carrier proteins RBP4 and TTR. Thus, ROH excretion might contribute to an increased risk of VA deficiency, especially in VLBW infants. Y1 - 2009 UR - http://www.springerlink.com/content/100382 U6 - https://doi.org/10.1007/s00467-008-0965-0 SN - 0931-041X ER - TY - JOUR A1 - Heunisch, Fabian A1 - von Einem, Gina A1 - Alter, Markus L. A1 - Weist, Andreas A1 - Dschietzig, Thomas A1 - Kretschmer, Axel A1 - Hocher, Berthold T1 - Urinary ET-1 excretion after exposure to radio-contrast media in diabetic patients and patients with preexisting mild impaired renal function JF - Life sciences : molecular, cellular and functional basis of therapy N2 - Aims: Contrast media-induced nephropathy (CIN) is associated with increased morbidity and mortality. The renal endothelin system has been associated with disease progression of various acute and chronic renal diseases. However, robust data coming from adequately powered prospective clinical studies analyzing the short and long-term impacts of the renal ET system in patients with CIN are missing so far. We thus performed a prospective study addressing this topic. Main methods: We included 327 patients with diabetes or renal impairment undergoing coronary angiography. Blood and spot urine were collected before and 24 h after contrast media (CM) application. Patients were followed for 90 days for major clinical events like need for dialysis, unplanned rehospitalization or death. Key findings: The concentration of ET-1 and the urinary ET-1/creatinine ratio decreased in spot urine after CM application (ET-1 concentration: 0.91 +/- 1.23pg/ml versus 0.63 +/- 1.03pg/ml, p<0.001; ET-1/creatinine ratio: 0.14 +/- 0.23 versus 0.09 +/- 0.19, p<0.001). The urinary ET-1 concentrations in patients with CIN decreased significantly more than in patients without CIN (-0.26 +/- 1.42pg/ml vs. -0.79 +/- 1.69pg/ml, p=0.041), whereas the decrease of the urinary ET-1/creatinine ratio was not significantly different (non-CIN patients: -0.05 +/- 0.30; CIN patients: -0.11 +/- 0.21, p=0.223). Urinary ET-1 concentrations as well as the urinary ET-1/creatinine ratio were not associated with clinical events (need for dialysis, rehospitalization or death) during the 90day follow-up after contrast media exposure. However, the urinary ET-1 concentration and the urinary ET-1/creatinine ratio after CM application were higher in those patients who had a decrease of GFR of at least 25% after 90days of follow-up. Significance: In general the ET-1 system in the kidney seems to be down-regulated after contrast media application in patients with moderate CIN risk. Major long-term complications of CIN (need for dialysis, rehospitalization or death) are not associated with the renal ET system. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license. KW - Urinary ET-1 KW - Clinical study KW - Radiocontrast media-induced nephropathy KW - Kidney Y1 - 2014 U6 - https://doi.org/10.1016/j.lfs.2013.12.233 SN - 0024-3205 SN - 1879-0631 VL - 118 IS - 2 SP - 440 EP - 445 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Chaykovska, Lyubov A1 - Heunisch, Fabian A1 - von Einem, Gina A1 - Hocher, Carl-Friedrich A1 - Tsuprykov, Oleg A1 - Pavkovic, Mira A1 - Sandner, Peter A1 - Kretschmer, Axel A1 - Chu, Chang A1 - Elitok, Saban A1 - Stasch, Johannes-Peter A1 - Hocher, Berthold T1 - Urinary cGMP predicts major adverse renal events in patients with mild renal impairment and/or diabetes mellitus before exposure to contrast medium JF - PLoS one N2 - Background The use of iodine-based contrast agents entails the risk of contrast induced nephropathy (CIN). Radiocontrast agents elicit the third most common cause of nephropathy among hospitalized patients, accounting for 11-12% of cases. CIN is connected with clinically significant consequences, including increased morbidity, prolonged hospitalization, increased risk of complications, potential need for dialysis, and increased mortality rate. The number of in hospital examinations using iodine-based contrast media has been significantly increasing over the last decade. In order to protect patients from possible complications of such examinations, new biomarkers are needed that are able to predict a risk of contrast-induced nephropathy. Urinary and plasma cyclic guanosine monophosphate (cGMP) concentrations are influenced by renal function. Urinary cGMP is primarily of renal cellular origin. Therefore, we assessed if urinary cGMP concentration may predict major adverse renal events (MARE) after contrast media exposure during coronary angiography. Methods Urine samples were prospectively collected from non-randomized consecutive patients with either diabetes or preexisting impaired kidney function receiving intra-arterial contrast medium (CM) for emergent or elective coronary angiography at the Charite Campus Mitte, University Hospital Berlin. Urinary cGMP concentration in spot urine was analyzed 24 hours after CM exposure. Patients were followed up over 90 days for occurrence of death, initiation of dialysis, doubling of plasma creatinine concentration or MARE. Results In total, 289 consecutive patients were included into the study. Urine cGMP/creatinine ratio 24 hours before CM exposure expressed as mean +/- SD was predictive for the need of dialysis (no dialysis: 89.77 +/- 92.85 mu M/mM, n = 277; need for dialysis: 140.3 +/- 82.90 mu M/mM, n = 12, p = 0.008), death (no death during follow-up: 90.60 +/- 92.50 mu M/mM, n = 280; death during follow-up: 169.88 +/- 81.52 mu M/mM, n = 9; p = 0.002), and the composite endpoint MARE (no MARE: 86.02 +/- 93.17 mu M/mM, n = 271; MARE: 146.64 +/- 74.68 mu M/mM, n = 18, p<0.001) during the follow-up of 90 days after contrast media application. cGMP/creatinine ratio stayed significantly increased at values exceeding 120 pM/mM in patients who developed MARE, required dialysis or died. Conclusions Urinary cGMP/creatinine ratio >= 120 mu M/mM before CM exposure is a promising biomarker for the need of dialysis and all-cause mortality 90 days after CM exposure in patients with preexisting renal impairment or diabetes. Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0195828 SN - 1932-6203 VL - 13 IS - 4 PB - PLoS CY - San Fransisco ER - TY - THES A1 - Mühlenbruch, Kristin T1 - Updating the german diabetes risk score - model extensions, validation and reclassification Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Raila, Jens A1 - Buchholz, Ingeborg A1 - Schweigert, Florian J. T1 - Untersuchungen zur Vitamin-A-Bindung im Harn von Hunden Y1 - 1997 ER - TY - JOUR A1 - Kerti, A. A1 - Baumane, Anita A1 - Buchholz, Ingeborg A1 - Schweigert, Florian J. T1 - Untersuchungen zur Verteilung von Vitamin A im Reproduktionstrakt der Wachtel, Coturnix coturnix japonica Y1 - 1997 ER - TY - THES A1 - Herbst, Uta T1 - Untersuchungen zur In-vitro-Zelltransformation in Dickdarmepithelzellen des Menschen und Dünndarmephithelzellen der Ratte durch Benzo(c)phenanthren-3,4-dihydrodiol-1,2-epoxide Y1 - 2012 CY - Potsdam ER - TY - GEN A1 - Mazurek, Nicole T1 - Untersuchungen zur Genexpression und Differenzierung muriner embryonaler Stammzellen in vitro zur Prädiktion eines embryotoxischen Potentials ausgewählter Chemikalien T1 - Investigations for gene expression and differentiation of murine embryonic stem cells in vitro to predict the embryotoxic potential of selected chemicals N2 - Der Embryonale Stammzelltest (EST) ist ein validierter In-vitro-Embryotoxizitätstest, der zur Untersuchung embryotoxischer Wirkungen von Chemikalien eingesetzt werden kann. Während des zehntägigen Differenzierungsassays differenzieren sich die pluripotenten murinen embryonalen Stammzellen (ES-Zellen) der Linie D3 in vitro in spontan kontrahierende Herzmuskelzellen. Dabei rekapitulieren sie Prozesse der frühen Embryogenese in vivo. Ein Zytotoxizitätsassay mit D3-Zellen und ausdifferenzierten, adulten 3T3-Maus-Fibroblasten dient der Ermittlung allgemeiner zytotoxischer Effekte und unterschiedlicher Sensitivitäten beider Zelllinien. Somit basiert der EST auf den beiden wichtigsten Mechanismen pränataler Toxizität, der Störung der Differenzierung und der Zytotoxizität. Ziel dieser Arbeit war es, mit Hilfe des EST das embryotoxische Potential der vier Chemikalien Trichostatin A (TSA), Methylazoxymethanolacetat (MAMac), Natriumdodecylsulfat (SDS) und Benzoesäure (BA) abzuschätzen. Dazu wurde mikroskopisch ermittelt, bei welcher Testsubstanzkonzentration in 50 % der während der In-vitro-Differenzierung gebildeten Embryonalkörperchen die Kardiomyozytendifferenzierung inhibiert wird (ID50). Außerdem wurde die halbmaximale Hemmkonzentration des Zellwachstums auf die beiden Zelllinien bestimmt (IC50D3 bzw. IC503T3). Als Erweiterung dieses konventionellen EST wurden mittels quantitativer Real Time-PCR an den Tagen 5, 7 und 10 der Differenzierung zusätzlich Genexpressionsanalysen etablierter herzmuskelspezifischer Markergene (Mesoderm Posterior 1, Tag 5; Myosin light chain 1, Tag 7 und 10) durchgeführt. Deren Expression korreliert in den ES-Zellen mit der embryonalen Herzdifferenzierung in vivo und kann zur Ermittlung der von der Prüfsubstanz hervorgerufenen halbmaximalen Hemmung der Genexpression in den Kardiomyozyten (IC50 Exp) herangezogen werden. Um letztlich embryotoxische Effekte in vivo auf Grundlage der ermittelten In-vitro-Daten abschätzen zu können, wurden die ermittelten Parameter mittels eines für den EST empirisch abgeleiteten mathematischen Prädiktionsmodells (PM) zur Klassifizierung der Testsubstanzen als nicht, schwach oder stark embryotoxisch herangezogen. Für jede der Substanzen waren die ermittelten Halbhemmkonzentrationen in den überwiegenden Fällen vergleichbar und führten unter Verwendung des PMs im konventionellen und im molekularen EST zu deren identischer Klassifizierung. TSA wurde als „stark embryotoxisch“ klassifiziert und beeinflusste insbesondere das Differenzierungspotential der ES-Zellen. Das als „schwach embryotoxisch“ klassifizierte SDS wirkte auf die D3-Zellen stärker differenzierungsinhibierend als zytotoxisch, hemmte jedoch das Wachstum der 3T3-Zellen bereits in deutlich niedrigeren Konzentrationen. MAMac und BA wurden als „nicht embryotoxisch“ klassifiziert. Bei ihnen stand die zytotoxische Wirkung deutlich im Vordergrund. Diese Prädiktionen stimmten mit In-vivo-Befunden überein, was von der Stabilität und der Brauchbarkeit der im konventionellen und molekularen EST ermittelten Parameter zeugte. Einzige Ausnahme war das als Entwicklungsneurotoxin in vivo bekannte MAMac. Da der EST auf mesodermaler Differenzierung basiert, können spezifische Effekte auf neuronale Entwicklungsprozesse offenbar nicht vollständig erfasst werden. Substanzkonzentrationen, die sich als differenzierungsinhibierend auf die morphologische Kardiomyozytendifferenzierung erwiesen haben, führten auch zu einer messbaren Repression der herzmuskelspezifischen Genexpression. Dabei erwies sich die IC50 Exp als ebenso sensitiv wie die konventionellen Parameter und als nutzbringende Ergänzung zu diesen, da sie bereits nach 5 bzw. 7 Tagen der In-vitro-Differenzierung eine mit dem mikroskopischen Parameter übereinstimmende Einschätzung des embryotoxischen Potentials der Chemikalien in vivo ermöglichte. Genexpressionsanalysen weiterer differenzierungsspezifischer Gene können zusätzlich zur Aufklärung zu Grunde liegender Mechanismen der Embryotoxizität von Testsubstanzen dienen. Somit kann der EST durch die Vorteile der Stammzelltechnologie und der Genexpressionsanalyse als neues prädiktives Screening-Instrument zur frühzeitigen Detektion embryotoxischer Substanzeffekte in der pharmazeutischen und chemischen Industrie genutzt werden. N2 - The embryonic stem cell test (EST) represents a validated in vitro embryotoxicity test that can be utilised for investigations of embryotoxic effects of chemical substances. During the 10-day differentiation assay the pluripotent murine embryonic stem cells (ES cells) of the D3 line differentiate in vitro into spontaneously beating cardiac muscle cells that can be observed microscopically. Thereby, ES cells recapitulate processes of early embryogenesis in vivo. A cytotoxicity assay with D3 cells as well as differentiated, adult 3T3 mouse fibroblasts is used to determine general cytotoxic effects and to consider differences in the sensitivity of both cell lines. Hence the EST is based on the two most important mechanisms of prenatal toxicity, such as inhibition of differentiation and cytotoxicity. The aim of the presented work consisted in the evaluation of the embryotoxic potential of the four chemicals trichostatin A (TSA), methylazoxymethanolacetate (MAMac), sodium dodecyl sulfate (SDS) and benzoic acid (BA) by means of the EST. For this purpose the concentration of the test substance that causes an inhibition of cardiomyocyte differentiation in 50 % of the embryoid bodies which are formed during the in vitro differentiation (ID50-value) and the halfmaximal inhibiting concentration of cell proliferation of D3 and 3T3 cell lines (IC50D3 and IC503T3) were determined. As extension of this conventional EST, the effect of test substances was investigated at the molecular level by gene expression analyses of cardiac specific genes (Mesoderm Posterior 1, day 5; Myosin light chain 1, day 7 and 10). Their expression in ES cells correlates with the embryonic heart differentiation in vivo. Quantitative Real Time-PCR gene expression analysis was used to determine the halfmaximal inhibition of the cardiomyocyte gene expression (IC50 Exp) caused by the test compound. To predict embryotoxic effects in vivo from the determined in vitro data, these parameters were used for the classification of the test chemicals as non, weak or strong embryotoxic via a mathematical prediction model (PM). In the majority of cases comparable halfmaximal inhibiting concentrations were calculated in the conventional and molecular EST that resulted in the identical classification of the tested chemicals concerning their embryotoxic potential. TSA was estimated as “strongly embryotoxic” and affected particularly the differentiation potential of the ES cells. SDS was classified as “weakly embryotoxic” and acted by inhibiting the differentiation of D3 cells at concentrations lower than cytotoxic concentrations but already repressed the growth of the 3T3 cells in significantly lower ranges. As to MAMac and BA that were classified as “non-embryotoxic” the cytotoxic effects on both cell lines predominated. These predictions were consistent with in vivo findings that testifies the stability and the usefulness of the parameters used in the conventional and molecular EST. MAMac, which is known as a developmental neurotoxin in vivo, represented the single exception. Its misclassification as compared to in vivo data may originate from the limitations of the model system that is based on mesodermal differentiation. Thus, specific effects on neuronal developmental processes obviously cannot be detected completely. Gene expression analysis showed that test substance concentrations which were proved to be inhibiting on the morphological differentiation of cardiomyocytes caused a repression of cardiac-specific marker gene expression as well. Thereby, IC50 Exp-values proved to be just as sensitive as the conventional parameters and can provide valuable and supportive data. They allowed a prediction of the embryotoxic potential of the chemicals in vivo already at day 5 and day 7 of in vitro differentiation. Moreover, gene expression analysis of appropriate differentiation specific genes could be used to investigate mechanisms that are responsible for embryotoxic properties of the test compounds. Thus, the EST is considered to represent a new, predictive screening test especially in the pharmaceutical industry to detect the embryotoxic potential of chemical compounds early in the process of compound development. KW - Embryonaler Stammzelltest (EST) KW - D3-Zellen KW - Differenzierungsassay KW - Zytotoxizitätsassay KW - Genexpressionsanalysen (qRT-PCR) KW - embryonic stem cell test (EST) KW - D3 cells KW - differentiation assay KW - cytotoxicity assay KW - gene expression analysis (qRT-PCR) Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-68912 ER - TY - THES A1 - Fuchs, Iris Judith T1 - Untersuchungen zur chemischen Transformation von intestinalen Epithelzellen der Ratte und des Menschen durch 2-Hydroxyamino-1-methyl-6-phenylimidazo(4,5-b)pyridin T1 - Investigations to chemical transformation of rat and human intestinal epithelial cells by 2-hydroxyamino-1-methyl-6-phenylimidazo(4,5-b)pyridine N2 - Die Zahl der Kolonkarzinome in den westlichen Industrieländern steigt in den letzten Jahren stetig an. Zu den Verbindungen, die mit der Zubereitung der Nahrung entstehen, mit ihr aufgenommen werden und die Kolonkanzerogenese möglicherweise begünstigen, gehört das heterozyklische aromatische PhIP, das bei der Erhitzung proteinreicher Nahrungsmittel entsteht. Neben zahlreichen Fütterungsversuchen an Nagern existieren auch Zellkulturmodelle zur Untersuchung der molekularen Mechanismen der PhIP-induzierten Kolonkanzerogenese. Die chemische Transformation von Zellen sollte durch wiederholte Exposition gegenüber dem hydroxylierten Metaboliten des Kanzerogens (N2-OH-PhIP) erzielt werden. Es wurden IEC-18-Zellen der Ratte und HCEC-Zellen des Menschen zur Untersuchung verwendet. Die Behandlung der IEC-18-Zellen führt nach 25 Behandlungszyklen mit Konzentrationen von 5 bis 20 µM nicht zur Transformation der Zellen. Die Anwesenheit von N2-OH-PhIP führt zu einer zehnfach erhöhten Induktion der GST-Aktivität, insbesondere der Untereinheiten GST-A1, -A3, -Pi und -T2, die für die effiziente Detoxifizierung des N-Acetoxy-Metaboliten vom N2-OH-PhIP verantwortlich sind. Bereits nach drei Behandlungen mit 1,5 µM N2-OH-PhIP konnte eine maligne Transformation der HCEC-Zellen erzielt werden. Die Zellen zeigten die charakteristischen Zeichen der Transformation: veränderte Wachstumseigenschaften wie klonales dreidimensionales Zellwachstum („pilling up“), Hemmung der Zell-Zell-Kontaktinhibierung, verkürzte Populationsverdopplungszeiten und tumorigene und metastasierende Eigenschaften. Außerdem exprimierten die N2-OH-PhIP-exponierten humanen Kolonzellen mit steigender Anzahl der Behandlungen größere Mengen des trunkierten APC-Proteins. Die bekannten PhIP-spezifischen Mutationen im APC-Gen resultieren in der Expression eines trunkierten Proteinproduktes und werden als frühe Ereignisse in der Kolonkanzerogenese betrachtet. Die zusammenfassende Betrachtung aller Ergebnisse zeigt, dass die IEC-18-Zelllinie zur chemischen Transformation durch N2-OH-PhIP ungeeignet ist. Dagegen wurde erstmalig eine vollständige chemische Transformation von Humandickdarmepithelzellen in vitro durch Exposition der humanen Kolonepithelzelllinie HCEC gegenüber dem Kolonkarzinogen N2-OH-PhIP erzielt. N2 - In the last few years a strong increase in the incidence of colorectal cancer has been observed. As to the specific components in processed food responsible for the induction of colon cancerogenesis , it has been suggested that heterocyclic aromatic amines (HAA), e.g. the most abundant HAA 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), which is formed in protein rich food, when it is cooked at high temperatures or over an open flame, might be involved in this process. Whereas a number of in vivo-models to study PhIP-mediated colon carcinogenesis are known, only a limited number of cell culture systems to study the HAA-mediated transformation of intestinal epithelial cells do in fact exist. In the present study IEC-18 cells (rat intestinal epithelial cells) and HCEC cells (human colon epithelial cells) were incubated with N2-OH-PhIP, the N-hydroxylated metabolite of PhIP. The IEC-18 cells could not be transformed despite 25 treatment cycles with 5 to 20 µM N2-OH-PhIP. This might be due to the fact that GST activity as well as the expression of the GST -A1, -A3, -Pi and -T2 units, which are responsible for the detoxication of the N-acetoxy derivative of PhIP were strongly induced by N2-OH-PhIP. In contrast, HCEC cells were malignantly transformed when exposed three times to 1.5 µM N2-OH-PhIP. The chemically-treated cells showed a reduced population doubling time, they lost cell-cell contact inhibition and started pilling up. Furthermore, if HCEC cells were injected subcutaneously into SCID mice tumors developed at the site of injection in all animals tested. The transformed HCEC cells also express high amounts of truncated APC protein, which in vivo appears at an early stage of colon cancerogenesis. Taken together, it has been shown that IEC-18 cells are not suitable for chemical transformation studies with the HAA metabolite N2-OH-PhIP. For the first time it has been shown that the HAA metabolite N2-OH-PhIP is indeed able to malignantly transform human colon epithelial cells in vitro. KW - maligne Transformation KW - Kolonkrebs KW - heterozyklische aromatische Amine KW - intestinale Epithelzellen KW - colorectal cancer KW - heterocyclic aromatic amines KW - intestinal epithelial cells KW - malignant transformation Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11807 ER - TY - JOUR A1 - Raila, Jens A1 - Bok, V. A1 - Buchholz, Ingeborg A1 - Schweigert, Florian J. T1 - Untersuchungen zum Vitamin-A-Stoffwechsel der Niere des Hundes Y1 - 1997 ER - TY - JOUR A1 - Steinhagen, Beate A1 - Siemann, A. A1 - Büscher, Ulrich A1 - Dudenhausen, Joachim W. A1 - Schweigert, Florian J. T1 - Untersuchungen zum Transfer von Carotinoiden aus dem Plasma in die Follikelflüssigkeit der Frau Y1 - 2000 ER - TY - THES A1 - Herles, Claudia T1 - Untersuchungen zum enzymatischen Abbau ausgewählter Flavanoide durch Eubacterium ramulus Y1 - 2003 ER - TY - JOUR A1 - Bok, V. A1 - Schweigert, Florian J. T1 - Untersuchungen zum Einfluß unterschiedlicher Vitamin A-Gehalte im Futter auf die Konzentration von Vitamin A im Plasma und die Ausscheidungen von Vitamin A über den Harn von Hunden Y1 - 1997 ER - TY - THES A1 - Gehrke, Janin T1 - Untersuchungen zu tanninbindenden Speichelproteinen des Rehs und anderer Wiederkäuer T1 - Investigation of tannin binding salivary proteins of roe deer and other ruminants N2 - Am Beispiel der Wiederkäuer wurde unter Zuhilfenahme von biochemischen und molekularbiologischen Methoden die Adaptation von Pflanzenfressern (Herbivoren) an pflanzliche Sekundärmetabolite wie z.B. Tannine untersucht. Tannine können in nicht an ihren Verzehr adaptierten Spezies durch ihr Proteinbindungsvermögen die Nahrungsverwertung und damit Wachstum und Gesundheit des Pflanzenfressers beeinträchtigen (antinutritive Wirkung). Einige Wiederkäuerarten wie z.B. das Reh (Capreolus capreolus) haben in ihrem Nahrungsspektrum viele stark tanninhaltige Pflanzen, leiden aber nicht unter den erwähnten postdigestiven Konsequenzen. Eine Möglichkeit, die antinutritive Wirkung von Tanninen zu neutralisieren, besteht in der Produktion tanninbindender Speichelproteine. Der Speichel verschiedener Wiederkäuerarten wurde auf das Vorhandensein tanninbindender Proteine untersucht. Diese Arten wurden so ausgewählt, dass alle drei Ernährungstypen (Konzentratselektierer, Intermediärtyp, Gras- und Rauhfutterfresser) in den Vergleich eingeschlossen werden konnten. Als Referenzspezies wurde der Konzentratselektierer Reh herangezogen. Die Speichelproteine des Rehs und die der Intermediärtypen (Rentier, Rangifer tarandus; Damhirsch, Cervus dama; Moschusochse, Ovibos moschatus) banden ungefähr doppelt so effektiv an hydrolysierbare Tannine (Tanninsäure), wie die der untersuchten Gras- und Rauhfutterfresser (Rind, Bos taurus; und Mufflon, Ovis orientalis musimon). Diese Abstufung zeigte sich auch bei der Untersuchung der Bindung an kondensierte Tannine (Quebracho). Eine Ausnahme stellte Mufflonspeichel dar, dieser band ebenso gut an Quebracho wie die Speichelproteine der anderen Ernährungstypen. Über eine Aminosäuretotalanalyse konnte festgestellt werden, dass der Speichel einiger untersuchter Wiederkäuerarten prolinreiche Proteine (PRPs) enthielt. Unter Ausnutzung ihrer Trichloressigsäure (TCA)-Löslichkeit wurden diese angereichert und genauer untersucht. Die Analyse der TCA-löslichen Speichelproteine der Konzentratselektierer (Reh, Elch) ergab einen relativen Prolingehalt von über 35 %, während beim Moschusochsen noch 29 % gemessen wurden. In Damhirsch- und Rinderspeichel wurden keine prolinreichen Proteine gefunden. Für die TCA-löslichen Speichelproteine des Rehs konnte eine hohe Tanninbindungskapazität nachgewiesen werden. Diese banden 24 - 30 x effektiver an Tannine als die TCA-löslichen Speichelproteine des Rindes. Die Tanninbindungskapazitäten der TCA-löslichen Speichelproteine von Moschusochse und Damhirsch waren ebenfalls höher als die des Rindes, aber niedriger als die des Rehs. Die Kohlenhydrat-Analyse der TCA-löslichen Speichelproteine des Rehs erbrachte, dass es sich bei ihnen um Glykoproteine handelt. Mittels Gelfiltration und zweidimensionaler Polyacrylamidgelektrophorese konnten fünf Proteingruppen mit Molekulargewichten zwischen 15 und 50 kd sowie isoelektrischen Punkten zwischen 4,0 und 8,2 detektiert werden. Von 15 dieser Proteine konnten die N-terminalen Aminosäuresequenzen ermittelt werden. Ausgehend von diesen Informationen wurden Reh-PRP spezifische mRNAs isoliert und partiell sequenziert. Die meisten dieser Fragmente hatten eine gemeinsame 18 Aminosäuren lange C-terminale Sequenz PPPEEQPEE/QSPDEE/DSPSE. Die Suche nach Übereinstimmungen der analysierten Sequenzen mit anderen Säugetier-PRPs in der Genbank ergab keine sinnvollen Ähnlichkeiten. Die Ergebnisse können zu Informationen über tanninbindende Proteine anderer Wiederkäuer führen. Die Sequenzinformationen stellen einen Ausgangspunkt bei der Analyse der evolutiven Zusammenhänge der Cerviden dar. N2 - Investigation of tannin binding salivary proteins of roe deer and other ruminants: In this work the adaptation of herbivores to plant secondary metabolites was investigated with help of biochemical and molecular biological methods. In unadapted species plant secondary metabolites as tannins can reduce food digestibility and thus diminish growth rate and health status (antinutritive action). Tannins act through its astringency, that means the high capacity to bind proteins, other macromolecules and metal ions. Some ruminant species feed on tannin containing plant but do not suffer from the mentioned nutritive consequences. The production of tannin binding proteins is one possible adaptation mechanism to neutralize the effects of the tannins. Saliva of six different ruminant species was investigated for the presence of tannin binding proteins. All three feeding types (concentrate selector, intermediate type and grass and roughage eater) were included in the comparison. Salivary proteins from roe deer (Capreolus capreolus, concentrate selector) and from the intermediate feeding types (rein deer, Rangifer tarandus; fallow deer, Cervus dama; musk ox, Ovibos moschatus) bound twice as effective to hydrolysable tannins (tannic acid) as those from the investigated grass and roughage eaters (cattle, Bos taurus; moufflon, Ovis orientalis). This differentiation could also be observed investigating the binding capacities to condensed tannins (quebracho) except for moufflon. Moufflon salivary proteins bound with the same intensity to quebracho as the salivary proteins from the other feeding types. Proline rich proteins (PRPs) could be accumulated from roe deer, moose and musk ox saliva by use of its solubility properties in 5 % trichloro acetic acid (TCA). Roe deer and moose TCA soluble salivary proteins contained more than 35 %, musk ox proteins 29 % proline. In fallow deer and cattle saliva PRPs could not be detected. A tannin binding assay demonstrated for the TCA soluble salivary proteins from roe deer, musk ox and fallow deer but not from cattle, that they are able to bind tannins. Roe deer salivary proteins bound 24 to 30 more effective to tannins as cattle proteins. Tannin binding capacity of the proteins from musk ox and fallow deer saliva was higher as those from cattle but lower as those from roe deer. For further analysis of ruminant tannin binding proteins we chose roe deer as reference species. Carbohydrate analysis of TCA soluble proteins from roe deer saliva showed that they were glycoproteins. With help of gel filtration and two dimensional polyacrylamid gel electrophoresis five proteins groups with molecular weights from 15 to 50 kd and isoelectric points from 4.0 to 8.2 could be detected. N-terminal amino acid sequences of 15 of the roe deer salivary TCA soluble proteins were determined by Edmann degradation. This information led to partially sequenced roe deer PRP specific cDNA. An 18 amino acid long C-terminal sequence was common in most of the clones. The obtained roe deer PRP sequences did not match with known mammalian PRP sequences from data banks. The finding in this work can lead to information about salivary tannin binding proteins in other ruminants. The sequence information represent a starting-point for the investigation of cervid evolution. KW - Speichel KW - tanninbindende Speichelproteine KW - prolinreiche Proteine KW - Wiederkäuer KW - Reh KW - saliva KW - tannin binding salivary proteins KW - proline rich proteins KW - ruminant KW - roe deer Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-0000444 ER - TY - THES A1 - Dokas, Janine T1 - Untersuchung zur Rolle von Tbc1d1 im Stoffwechsel anhand von Mausmodellen Y1 - 2012 CY - Potsdam ER - TY - THES A1 - Bernhardt, Ulrike T1 - Untersuchung zur Rolle von Adapterprotein-Komplexen im Targeting der Glucosetransporter GLUT8 und GLUT4 Y1 - 2008 ER - TY - THES A1 - Döcke, Stephanie T1 - Untersuchung von ausgewählten pathogenetischen Signalwegen der humanen nicht-alkoholischen Fettlebererkrankung Y1 - 2013 CY - Potsdam ER - TY - THES A1 - Machowetz, Anja T1 - Untersuchung kardioprotektiver Wirkungen des Olivenöles und seiner phenolischen Komponenten in einer Gruppe gesunder deutscher Männer T1 - Cardioprotective effects of olive oil and its phenolic compounds in healthy German men N2 - "Untersuchung kardioprotektiver Wirkungen des Olivenöles und seiner phenolischen Komponenten in einer Gruppe gesunder deutscher Männer" EINLEITUNG: Epidemiologische Daten belegen, dass die mediterrane Ernährung mit einer niedrigen Inzidenz an mit oxidativen Stress assoziierten kardiovaskulären Erkrankungen einhergeht. Dabei wird vor allem dem Olivenöl, als Hauptfettlieferant in der mediterranen Ernährung, eine kardioprotektive Wirkung zugesprochen. Olivenöl zeichnet sich neben dem hohen Gehalt an einfach ungesättigten Fettsäuren (MUFA) durch ein reichhaltiges Spektrum an phenolischen Verbindungen aus, deren antioxidative Wirkung bereits zahlreichen in in vitro Studien beschrieben wurde. Demnach könnte der Verzehr von phenolreichem Olivenöl auch in vivo vor oxidativen Schädigungen schützen und somit das Risiko für kardiovaskuläre Erkrankungen senken. ZIELSTELLUNG: Untersuchung der kardioprotektiven Wirkung von Olivenöl und seiner phenolischen Komponenten in einer Gruppe gesunder deutscher Männer. METHODE: Dazu wurde eine randomisierte cross-over doppelt-verblindete Interventionsstudie an 70 gesunden Männern zwischen 20 - 60 Jahren im Raum Berlin-Brandenburg durchgeführt. In jeweils drei dreiwöchigen Interventionsphasen konsumierten die Probanden täglich 25 ml natives (phenolreich), gemischtes (mittlerer Phenolgehalt) und raffiniertes (annähernd phenolfrei) Olivenöl, was sich ausschließlich im Gehalt an phenolischen Verbindungen unterschied. Das Olivenöl sollte dabei die gewöhnlich verzehrten Fette ersetzen. Die Interventionsphasen waren durch zweiwöchige Wash out-Phasen unterbrochen. Die Erhebung der Blutlipide, Biomarker der Lipidperoxidation und endogene Antioxidantien erfolgte zu Studienbeginn sowie zu Beginn und Ende jeder Verzehrsperiode.ERGEBNISSE: Bei den Blutlipiden sowie den Biomarkern der Lipidperoxidation und den endogenen Antioxidantien konnte keine signifikante Veränderung in Abhängigkeit vom Phenolgehalt der applizierten Olivenöle nachgewiesen werden. Einzig die Glutathion-Reduktase-Aktivität stieg mit zunehmendem Gehalt an phenolischen Verbindungen (pTrend = 0,041). Unabhängig von der Konzentration der Phenole im Olivenöl wurde bei den Probanden durch den Olivenölverzehr eine Senkung von Gesamtcholesterol (p = 0,007) und Triglyzeride (p = 0,013) im Serum erzielt. Diese Wirkung geht einher mit einem gestiegenen MUFA-Anteil in der Ernährung aufgrund des Olivenölkonsums (p < 0,001). SCHLUSSFOLGERUNG: Die Hypothese, dass die Phenole im Olivenöl aufgrund ihrer in in vitro und Tierstudien beschriebenen antioxidativen Wirkung dem Olivenöl neben dem einzigartigen Fettsäureprofil eine zusätzliche kardioprotektive Wirkung bescheren, konnte in der vorliegenden Studie nicht gezeigt werden. Dennoch konnte durch den Olivenölverzehr und der damit einhergehenden Erhöhung des MUFA-Anteils in der Ernährung eine vorteilhafte Beeinflussung der Blutlipide erzielt werden. Obgleich Olivenöl nicht das vorwiegend verzehrte Fett in Deutschland darstellt, zeigten die befragten Probanden eine hohe Akzeptanz. Folglich könnte die Integration von Olivenöl in die habituelle Ernährung einen Beitrag zur Senkung des kardiovaskulären Erkrankungsrisikos leisten. N2 - "Cardioprotective effects of olive oil and its phenolic compounds in healthy German men" BACKGROUND: Epidemiological data show that the Mediterranean diet is related to a low incidence of oxidative stress associated cardiovascular diseases. In particular, olive oil, which is the most consumed alimentary fat in the Mediterranean diet, is discussed to be cardio protective. Besides its high monounsaturated fatty acid content olive oil contains a remarkable amount of phenolic compounds. Results from in vitro and animal studies suggest that these phenols are powerful antioxidants. Thus, consumption of olive oil phenols also could inhibit oxidative damage in vivo and therefore could reduce the risk of cardiovascular diseases. OBJECTIVE: To investigate the cardioprotective effect of olive oil and its phenolic compounds in healthy German men. METHODS: Therefore, a randomised, cross-over, double-blind intervention trial in 70 healthy men aged 20 - 60 years from the Berlin-Brandenburg area was conducted. Subjects were randomised for three periods of three weeks to replace their usually consumed fat by daily 25 ml of virgin (high-phenolic), common (medium-phenolic) and refined (low-phenolic) olive oil, which vary only in their content of phenolic compounds. Each intervention was separated by a two-week wash-out period. Blood lipids, lipid peroxidation biomarker and endogenous antioxidants were assessed at study baseline and the beginning and end of each intervention period. RESULTS: In the total study population, blood lipids, biomarker of lipid peroxidation and endogenous antioxidants were not affected by the phenolic content of the olive oils administered. Solely, a concentration-dependent increase in glutathion-reductase activity could be observed (pTrend = 0.041). A significant reduction in serum total cholesterol (p = 0.007) and triglycerides (p = 0.013) after of olive oil consumption was assessed, which was independent from the content of phenolic compounds in the olive oil. This effect goes along with an increased monounsaturated fatty acids proportion in the habitual diet of the subjects as a result of the olive oil consumption (p < 0.001). CONCLUSION: The hypothesis, that phenolic compounds in olive oil due to its antioxidative properties reported in in vitro and animal studies provide additional cardioprotective effects besides those attributed to its unique fatty acids profile could not be supported by this study. However, olive oil consumption exert beneficial effects on blood lipids, which could be ascribed to the increased monounsaturated fatty acid content in the diet. Even though olive oil is not the main source of fat in Germany, the interviewed participants showed a high acceptance. Thus, integration of olive oil into the habitual diet could contribute to a risk reduction in cardiovascular diseases among German men. KW - Olivenöl KW - Phenole KW - Kontrollierte klinische Studie KW - Kardiovaskuläre Krankheit KW - Oxidativer Stress KW - mediterrane Ernährung KW - Mediterranean Diet Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10432 ER - TY - THES A1 - Schmidt, Antje T1 - Untersuchung des Recyclings Kaede-fusionierter Corticotropin-Releasing-Factor Rezeptoren Typ 1 T1 - Use of Kaede-Fusions to Visualize Recycling of the Corticotropin-Releasing Factor Receptor Type 1 N2 - Aktivierte G-Protein-gekoppelte Rezeptoren (GPCR) werden schnell desensitisiert, internalisiert und anschließend entweder lysosomal degradiert oder zur Plasmamembran (PM) recycelt. Zur Resensitisierung der Zellen tragen neben recycelten auch neusynthetisierte Rezeptoren bei. Die Überlagerung beider Prozesse erschwert die Untersuchung des Rezeptorrecyclings. In dieser Arbeit sollte mit Hilfe des photokonvertierbaren Fluoreszenzproteins Kaede eine Technik entwickelt werden, mit der es möglich ist Recycling- von Neusyntheseprozessen zu trennen und das Recycling von GPCR mikroskopisch in Echtzeit zu beobachten. Als Modellproteine wurden der Vasopressin-1a-Rezeptor V1aR (recycelnder Rezeptor), der Vasopressin-2-Rezeptor V2R (degradierter Rezeptor) und der Corticotropin-Releasing Factor-Rezeptor Typ 1 (CRF1R) verwendet, wobei bei Letzterem untersucht werden sollte, ob er nach Stimulation zur PM zurücktransportiert wird. Da Kaede als fluoreszierendes Protein mit den GPCR fusioniert wird, wurde zunächst überprüft, ob es die Eigenschaften der Rezeptoren verändert und generell für Transportstudien geeignet ist. Eventuell könnte die bereits publizierte Tetramerisierung von Kaede seine Anwendung verhindern oder erschweren. Mittels Fluoreszenz-Korrelationsspektroskopie konnte gezeigt werden, dass Kaede nicht tetramerisiert, wenn es an ein Membranprotein fusioniert ist. Außerdem konnte in in vitro- und Zellkulturexperimenten belegt werden, dass die native und die photokonvertierte Form von Kaede gleichermaßen stabil sind. Darüber hinaus zeigten Kaede-fusionierte GPCR sowohl in Kolokalisationsstudien als auch in Agonistbindungs- und Rezeptoraktivierungsexperimenten die gleichen Eigenschaften wie CFP- bzw. die unfusionierte Rezeptoren. Lediglich die Expression der Kaede-fusionierten Rezeptoren war geringer. Parallel wurde anhand der bereits publizierten Kaede-Struktur versucht, die Tetramerisierung des Proteins durch den Austausch interagierender Aminosäuren zu unterbinden. Die eingeführten Mutationen bewirkten aber eine Fehlfaltung des Proteins und damit den Verlust der Fluoreszenz. Da zuvor gezeigt werden konnte, dass Kaede-fusionierte Membranproteine nicht tetramerisieren und nicht die Eigenschaften der fusionierten Proteine verändern, war monomerisiertes Kaede zur Untersuchung des Rezeptorrecyclings nicht notwendig. Im zweiten Teil der Arbeit wurde mit Hilfe von Kaede-Fusionsproteinen und mikroskopischer Testsysteme das noch unbekannte Recyclingverhalten des CRF1R untersucht. Hierfür wurden die Kaede-fusionierten Rezeptoren in eukaryotischen Zellen exprimiert und mit Agonisten internalisiert. Die internalisierten Rezeptoren wurden in Endosomen selektiv mit UV-Strahlung photokonvertiert. Anschließend wurde der Transport der photokonvertierten Form verfolgt. Sowohl beim CRF1R als auch beim V1aR wurden Signale in der PM detektiert, beim V2R hingegen nicht. Dies zeigt, dass es sich beim CRF1R um einen recycelnden Rezeptor handelt. Die als Kontrolle eingesetzten Rezeptoren verhielten sich in diesem Experiment wie erwartet: Der V1aR wurde zur PM zurücktransportiert, der V2R nicht. Diese Ergebnisse konnten mit Hilfe biochemischer und durchflusscytometrischer Experimente bestätigt werden. Die Internalisierung des CRF1R verläuft Clathrin-vermittelt in Anwesenheit von β-Arrestin. Je nach Stabilität der β Arrestin-Interaktion unterscheidet man zwei Klassen von Rezeptoren: Klasse A-Rezeptoren interagieren transient mit β Arrestin und können recyceln. Im Gegensatz dazu gehen Klasse B-Rezeptoren eine stabile Interaktion mit β Arrestin ein und werden nach Internalisierung degradiert. In mikroskopischen Untersuchungen konnte für die aktivierten CRF1R und V1aR eine Rekrutierung von β Arrestin zur PM und eine transiente Interaktion mit β Arrestin gezeigt werden (Klasse A-Rezeptoren). Für den V2R wurde dagegen eine stabile Interaktion mit β Arrestin beobachtet (Klasse B-Rezeptor). Diese Daten stützen die Ergebnisse des Kaede-basierten Recyclingversuchs und zeigen, dass der CRF1R ein recycelnder Rezeptor ist. Ferner wurde untersucht, ob der CRF1R zu den schnell oder langsam recycelnden Rezeptoren zählt. Schnell recycelnde Rezeptoren werden direkt aus frühen Endosomen, langsam recycelnde hingegen über das Trans-Golgi-Netzwerk (TGN) bzw. über Recycling-Endosomen zur PM transportiert. Als Marker für das TGN oder die Recycling-Endosomen wurde Rab11 verwendet. In Kolokalisationsstudien konnte gezeigt werden, dass der CRF1R den langsam recycelnden Rezeptoren zugeordnet werden kann. Zusammenfassend konnte in dieser Arbeit belegt werden, dass Kaede als Fusionspartner für Membranproteine genutzt werden kann um deren Transport in Echtzeit zu studieren. Damit wurde erstmals eine mikroskopische Methode etabliert, die es erlaubt recycelnde von neusynthetisierten Rezeptoren zu unterscheiden. Mit Hilfe dieser Methode war es möglich zu zeigen, dass der CRF1R ein recycelnder Rezeptor ist. N2 - Upon ligand binding and receptor activation, G protein-coupled receptors (GPCR) are rapidly desensitized, internalized and subsequently degraded in lysosomes or recycled back to the plasma membrane. Resensitization of the cell is enabled by both recycling receptors and newly synthesized receptors. The overlap of recycling and synthesis processes largely complicates the study of GPCR recycling mechanisms. One aim of this thesis was to develop a new microscopic technique for real-time visualization of GPCR recycling using the photoconvertible Kaede protein allowing to differentiate newly synthesized from recycling receptors. As model proteins, the V1aR (recycling receptor), the V2R (degraded receptor) and the CRF1R were used. In the case of the CRF1R, it was unknown whether this receptor recycles to the plasma membrane following agonist-promoted internalization. The study of the CRF1R recycling behaviour was another objective of this work. As the Kaede protein is fused C-terminally to the GPCRs, an influence on the pharmacological and trafficking properties of the receptors must be excluded. The previously published tetramerization of Kaede, for example, might hinder or even prevent its usability. To assess for the applicability of Kaede, fluorescence correlation spectroscopy experiments were performed and it was demonstrated that Kaede fused to membrane proteins cannot form tetramers in contrast to the soluble form. In vitro studies and experiments in cell culture revealed that both the native and the photoconverted Kaede are equally stable. Moreover Kaede-fused GPCR displayed the same pharmacological and trafficking properties as the untagged or CFP-tagged receptors. Only the expression levels of the Kaede fusion proteins were reduced, yet this did not affect the microscopic experiments. In parallel to these experiments, the interacting amino acids of the tetrameric Kaede were substituted according to the previously published crystal structure of the protein. Unfortunately, these mutations induced protein misfolding thereby causing loss of fluorescence functions. However, since it could be shown that membrane protein-fused Kaede cannot tetramerize, the monomerized Kaede was no more essential for the microscopic study of receptor recycling. In the second part of this work, Kaede-fusions were used to study the recycling behaviour of the CRF1R and the V1aR and V2R control proteins by the novel real-time recycling assay at the laser scanning microscope. To this end, HEK 293 cells expressing the Kaede-fused receptors were treated with agonist to induce receptor internalization. Internalized receptors were selectively photoconverted in endosomes using UV-irradiation and the subcellular fate of the new fluorescence signals was studied. In the case of the CRF1R, signals of the photoconverted receptors could be detected in the plasma membrane indicating that the CRF1R belongs to the family of recycling receptors. The control receptors showed the expected results: The V1aR recycled back to the plasma membrane whereas the V2R did not. These results were confirmed with biochemical and flow cytometry measurements. The CRF1R internalizes in a clathrin-dependent way via the adaptor protein AP2, dynamin and β arrestin. Depending on the stability of the resulting receptor-β-arrestin-complex, two classes of receptors can be differentiated. Class A receptors are recycling receptors undergoing a more transient β-arrestin interaction. In contrast, class B receptors stably interact with β-arrestin and are degraded after internalization. In the case of the CRF1R and V1aR, microscopic analyzes demonstrated that β arrestin transiently interacts with the stimulated CRF1R and V1aR indicating again that these receptors are recycling GPCRs (class A receptors). The V2R, in contrast, revealed a stable interaction (class B receptor). Moreover, it was studied whether the CRF1R recycles rapidly or more slowly to the plasma membrane. Rapidly recycling receptors are recruited out of early endosomes whereas slowly recycling receptors pass the trans-golgi-network or recycling endosomes before reaching the cell surface. Rab11 colocalization studies demonstrated that the CRF1R belongs to the family of slowly recycling receptors. In conclusion, a novel microscopic technique was established allowing to study GPCR recycling in real-time and to differentiate recycling and synthesis processes. Moreover, it was shown that the CRF1R belongs to the family of recycling receptors. The Kaede technique seems to be very well suited to study membrane protein trafficking in general. KW - Corticotropin-Releasing Factor Rezeptor Typ 1 KW - Recycling KW - GPCR KW - Kaede KW - Corticotropin-Releasing Factor Receptor Type 1 KW - Recycling KW - GPCR KW - Kaede Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-34902 ER - TY - THES A1 - Engelke, Christina T1 - Untersuchung der Polymorphismen der humanen Sulfotransferasen 1A1 und 1A2 im Rahmen der "European Prospective Investigation into Cancer and Nutrition" in Potsdam Y1 - 2000 ER - TY - THES A1 - Waizenegger, Julia T1 - Untersuchung der molekularen Toxizität von Pyrrolizidinalkaloiden in der humanen Hepatomzelllinie HepaRG BT - strukturbedingte Effekte nach einmaliger und wiederholter Exposition Y1 - 2018 ER - TY - THES A1 - Ott, Christiane T1 - Untersuchung der intrazellulären Proteolyse während der Zellalterung BT - Einfluss von Proteinaggregaten und Proteinmodifikationen Y1 - 2016 ER - TY - GEN A1 - Kumar, Kevin K. A1 - Goodwin, Cody R. A1 - Uhouse, Michael A. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael A. A1 - McLean, John A. A1 - Bowman, Aaron B. T1 - Untargeted metabolic profiling identifies interactions between Huntington's disease and neuronal manganese status N2 - Manganese (Mn) is an essential micronutrient for development and function of the nervous system. Deficiencies in Mn transport have been implicated in the pathogenesis of Huntington's disease (HD), an autosomal dominant neurodegenerative disorder characterized by loss of medium spiny neurons of the striatum. Brain Mn levels are highest in striatum and other basal ganglia structures, the most sensitive brain regions to Mn neurotoxicity. Mouse models of HD exhibit decreased striatal Mn accumulation and HD striatal neuron models are resistant to Mn cytotoxicity. We hypothesized that the observed modulation of Mn cellular transport is associated with compensatory metabolic responses to HD pathology. Here we use an untargeted metabolomics approach by performing ultraperformance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS) on control and HD immortalized mouse striatal neurons to identify metabolic disruptions under three Mn exposure conditions, low (vehicle), moderate (non-cytotoxic) and high (cytotoxic). Our analysis revealed lower metabolite levels of pantothenic acid, and glutathione (GSH) in HD striatal cells relative to control cells. HD striatal cells also exhibited lower abundance and impaired induction of isobutyryl carnitine in response to increasing Mn exposure. In addition, we observed induction of metabolites in the pentose shunt pathway in HD striatal cells after high Mn exposure. These findings provide metabolic evidence of an interaction between the HD genotype and biologically relevant levels of Mn in a striatal cell model with known HD by Mn exposure interactions. The metabolic phenotypes detected support existing hypotheses that changes in energetic processes underlie the pathobiology of both HD and Mn neurotoxicity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 232 KW - cells KW - coenzyme-a KW - database KW - energy-metabolism KW - glutathione KW - hallervorden-spatz-syndrome KW - mobility-mass spectrometry KW - model KW - neurodegeneration KW - neurotoxicity Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-94314 SP - 363 EP - 370 ER - TY - JOUR A1 - Kumar, Kevin K. A1 - Goodwin, Cody R. A1 - Uhouse, Michael A. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael A. A1 - McLean, John A. A1 - Bowman, Aaron B. T1 - Untargeted metabolic profiling identifies interactions between Huntington's disease and neuronal manganese status JF - Metallomics N2 - Manganese (Mn) is an essential micronutrient for development and function of the nervous system. Deficiencies in Mn transport have been implicated in the pathogenesis of Huntington's disease (HD), an autosomal dominant neurodegenerative disorder characterized by loss of medium spiny neurons of the striatum. Brain Mn levels are highest in striatum and other basal ganglia structures, the most sensitive brain regions to Mn neurotoxicity. Mouse models of HD exhibit decreased striatal Mn accumulation and HD striatal neuron models are resistant to Mn cytotoxicity. We hypothesized that the observed modulation of Mn cellular transport is associated with compensatory metabolic responses to HD pathology. Here we use an untargeted metabolomics approach by performing ultraperformance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS) on control and HD immortalized mouse striatal neurons to identify metabolic disruptions under three Mn exposure conditions, low (vehicle), moderate (non-cytotoxic) and high (cytotoxic). Our analysis revealed lower metabolite levels of pantothenic acid, and glutathione (GSH) in HD striatal cells relative to control cells. HD striatal cells also exhibited lower abundance and impaired induction of isobutyryl carnitine in response to increasing Mn exposure. In addition, we observed induction of metabolites in the pentose shunt pathway in HD striatal cells after high Mn exposure. These findings provide metabolic evidence of an interaction between the HD genotype and biologically relevant levels of Mn in a striatal cell model with known HD by Mn exposure interactions. The metabolic phenotypes detected support existing hypotheses that changes in energetic processes underlie the pathobiology of both HD and Mn neurotoxicity. KW - hallervorden-spatz-syndrome KW - mobility-mass spectrometry KW - energy-metabolism KW - coenzyme-a KW - model KW - neurotoxicity KW - glutathione KW - database KW - cells KW - neurodegeneration Y1 - 2015 U6 - https://doi.org/10.1039/C4MT00223G SN - 1756-591X SN - 1756-5901 VL - 7 SP - 363 EP - 370 PB - RSC Publ. CY - Cambridge ER - TY - JOUR A1 - Kumar, Kevin K. A1 - Goodwin, Cody R. A1 - Uhouse, Michael A. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael A. A1 - McLean, John A. A1 - Bowman, Aaron B. T1 - Untargeted metabolic profiling identifies interactions between JF - Metallomics : integrated biometal science Y1 - 2015 U6 - https://doi.org/10.1039/c4mt00223g SN - 1756-5901 SN - 1756-591X VL - 7 IS - 2 SP - 363 EP - 370 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Schell, Mareike A1 - Wardelmann, Kristina A1 - Kleinridders, Andre T1 - Untangling the effect of insulin action on brain mitochondria and metabolism JF - Journal of neuroendocrinology N2 - The regulation of energy homeostasis is controlled by the brain and, besides requiring high amounts of energy, it relies on functional insulin/insulin-like growth factor (IGF)-1 signalling in the central nervous system. This energy is mainly provided by mitochondria in form of ATP. Thus, there is an intricate interplay between mitochondrial function and insulin/IGF-1 action to enable functional brain signalling and, accordingly, propagate a healthy metabolism. To adapt to different nutritional conditions, the brain is able to sense the current energy status via mitochondrial and insulin signalling-dependent pathways and exerts an appropriate metabolic response. However, regional, cell type and receptor-specific consequences of this interaction occur and are linked to diverse outcomes such as altered nutrient sensing, body weight regulation or even cognitive function. Impairments of this cross-talk can lead to obesity and glucose intolerance and are linked to neurodegenerative diseases, yet they also induce a self-sustainable, dysfunctional 'metabolic triangle' characterised by insulin resistance, mitochondrial dysfunction and inflammation in the brain. The identification of causal factors deteriorating insulin action, mitochondrial function and concomitantly a signature of metabolic stress in the brain is of utter importance to offer novel mechanistic insights into development of the continuously rising prevalence of non-communicable diseases such as type 2 diabetes and neurodegeneration. This review aims to determine the effect of insulin action on brain mitochondrial function and energy metabolism. It precisely outlines the interaction and differences between insulin action, insulin-like growth factor (IGF)-1 signalling and mitochondrial function; distinguishes between causality and association; and reveals its consequences for metabolism and cognition. We hypothesise that an improvement of at least one signalling pathway can overcome the vicious cycle of a self-perpetuating metabolic dysfunction in the brain present in metabolic and neurodegenerative diseases. KW - brain KW - energy homeostasis KW - inflammation KW - insulin signalling KW - metabolism KW - mitochondrial function Y1 - 2021 U6 - https://doi.org/10.1111/jne.12932 SN - 0953-8194 SN - 1365-2826 VL - 33 IS - 4 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Knebel, Constanze A1 - Neeb, Jannika A1 - Zahn, Elisabeth A1 - Schmidt, Flavia A1 - Carazo, Alejandro A1 - Holas, Ondej A1 - Pavek, Petr A1 - Püschel, Gerhard Paul A1 - Zanger, Ulrich M. A1 - Süssmuth, Roderich A1 - Lampen, Alfonso A1 - Marx-Stoelting, Philip A1 - Braeuning, Albert T1 - Unexpected Effects of Propiconazole, Tebuconazole, and Their Mixture on the Receptors CAR and PXR in Human Liver Cells JF - Toxicological sciences N2 - Analyzing mixture toxicity requires an in-depth understanding of the mechanisms of action of its individual components. Substances with the same target organ, same toxic effect and same mode of action (MoA) are believed to cause additive effects, whereas substances with different MoAs are assumed to act independently. Here, we tested 2 triazole fungicides, propiconazole, and tebuconazole (Te), for individual and combined effects on liver toxicity-related endpoints. Both triazoles are proposed to belong to the same cumulative assessment group and are therefore thought to display similar and additive behavior. Our data show that Te is an antagonist of the constitutive androstane receptor (CAR) in rats and humans, while propiconazole is an agonist of this receptor. Both substances activate the pregnane X-receptor (PXR) and further induce mRNA expression of CYP3A4. CYP3A4 enzyme activity, however, is inhibited by propiconazole. For common targets of PXR and CAR, the activation of PXR by Te overrides CAR inhibition. In summary, propiconazole and Te affect different hepatotoxicity-relevant cellular targets and, depending on the individual endpoint analyzed, act via similar or dissimilar mechanisms. The use of molecular data based on research in human cell systems extends the picture to refine cumulative assessment group grouping and substantially contributes to the understanding of mixture effects of chemicals in biological systems. KW - triazole fungicides KW - constitutive androstane receptor KW - pregnane X-receptor KW - enzyme induction KW - liver toxicity KW - mixtures Y1 - 2018 U6 - https://doi.org/10.1093/toxsci/kfy026 SN - 1096-6080 SN - 1096-0929 VL - 163 IS - 1 SP - 170 EP - 181 PB - Oxford Univ. Press CY - Oxford ER - TY - THES A1 - Aleksandrova, Krasimira T1 - Understanding the link between obesity and colorectal cancer BT - the role of biomarkers of iflammation, immunity and metabolic dysfunction Y1 - 2020 ER - TY - CHAP A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - Müller, Steffen A1 - Mayer, Frank T1 - Ultrasound evaluation of the patellar tendon cross-sectional area and its relation to maximum force T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2012 SN - 0195-9131 VL - 44 SP - 714 EP - 714 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Gerecke, Christian A1 - Mascher, Conny A1 - Gottschalk, Uwe A1 - Kleuser, Burkhard A1 - Scholtka, Bettina T1 - Ultrasensitive detection of unknown colon cancer-initiating mutations using the example of the adenomatous polyposis coli gene JF - Cancer prevention research N2 - Detection of cancer precursors contributes to cancer prevention, for example, in the case of colorectal cancer. To record more patients early, ultrasensitive methods are required for the purpose of noninvasive precursor detection in body fluids. Our aim was to develop a method for enrichment and detection of known as well as unknown driver mutations in the Adenomatous polyposis coli (APC) gene. By coupled wild-type blocking (WTB) PCR and high-resolution melting (HRM), referred to as WTB-HRM, a minimum detection limit of 0.01% mutant in excess wild-type was achieved according to as little as 1 pg mutated DNA in the assay. The technique was applied to 80 tissue samples from patients with colorectal cancer (n = 17), adenomas (n = 50), serrated lesions (n = 8), and normal mucosa (n = 5). Any kind of known and unknown APC mutations (deletions, insertions, and base exchanges) being situated inside the mutation cluster region was distinguishable from wild-type DNA. Furthermore, by WTB-HRM, nearly twice as many carcinomas and 1.5 times more precursor lesions were identified to be mutated in APC, as compared with direct sequencing. By analyzing 31 associated stool DNA specimens all but one of the APC mutations could be recovered. Transferability of the WTB-HRM method to other genes was proven using the example of KRAS mutation analysis. In summary, WTB-HRM is a new approach for ultrasensitive detection of cancer-initiating mutations. In this sense, it appears especially applicable for noninvasive detection of colon cancer precursors in body fluids with excess wild-type DNA like stool. Cancer Prev Res; 6(9); 898-907. (C) 2013 AACR. Y1 - 2013 U6 - https://doi.org/10.1158/1940-6207.CAPR-13-0145 SN - 1940-6207 VL - 6 IS - 9 SP - 898 EP - 907 PB - American Association for Cancer Research CY - Philadelphia ER - TY - JOUR A1 - Rötzler, Jochen A1 - Romer, R. L. A1 - Budzinski, Hubertus A1 - Oberhänsli, Roland T1 - Ultrahigh-temperature high-pressure granulites from Tirschheim, Saxon Granulite Massif, Germany : P-T-t path and geotectonic implications N2 - 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 Y1 - 2004 SN - 0935-1221 ER - TY - JOUR A1 - Hoie, Lars H. A1 - Sjoholm, Ake A1 - Guldstrand, Marie A1 - Zunft, Hans-Joachim Franz A1 - Lueder, Wolfgang A1 - Graubaum, Hans-Joachim A1 - Grünwald, Jörg T1 - Ultra heat treatment destroys cholesterol-lowering effect of soy protein JF - International journal of food sciences and nutrition N2 - A randomized, placebo-controlled, double-blind clinical study was performed to investigate the dose-dependent response of serum cholesterol after consuming an ultra-heat-treated milk containing a soy protein preparation. Eighty hypercholesterolemic subjects were assigned to one of four study groups receiving 12.5 or 25 g soy protein (active treatment) or casein (placebo) daily over a period of 4 weeks. The trial substances were provided as ready-made, ultra-heated milk preparations. Before and after the treatment, serum concentrations of total, low-density lipoprotein, and high-density lipoprotein cholesterol were determined. Unexpectedly, at the end of the study, low-density lipoprotein cholesterol concentrations were significantly increased compared with baseline in all study groups. The magnitude of this increase (17 - 19%) was similar in all active and placebo study groups. Soy protein supplements previously shown to be effective in reducing serum cholesterol had in this study no such lipid-lowering effect after ultra heat treatment. KW - soy KW - protein KW - cholesterol KW - ultra heat treatment Y1 - 2006 U6 - https://doi.org/10.1080/09637480601009059 SN - 0963-7486 VL - 57 SP - 512 EP - 519 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Wallmeyer, Leonie A1 - Dietert, Kristina A1 - Sochorova, Michaela A1 - Gruber, Achim D. A1 - Kleuser, Burkhard A1 - Vavrova, Katerina A1 - Hedtrich, Sarah T1 - TSLP is a direct trigger for T cell migration in filaggrin-deficient skin equivalents JF - Scientific reports N2 - Mutations in the gene encoding for filaggrin (FLG) are major predisposing factors for atopic dermatitis (AD). Besides genetic predisposition, immunological dysregulations considerably contribute to its pathophysiology. For example, thymic stromal lymphopoietin (TSLP) is highly expressed in lesional atopic skin and significantly contributes to the pathogenesis of AD by activating dendritic cells that then initiate downstream effects on, for example, T cells. However, little is known about the direct interplay between TSLP, filaggrin-deficient skin and other immune cells such as T lymphocytes. In the present study, FLG knockdown skin equivalents, characterised by intrinsically high TSLP levels, were exposed to activated CD4(+) T cells. T cell exposure resulted in an inflammatory phenotype of the skin equivalents. Furthermore, a distinct shift from a Th1/Th17 to a Th2/Th22 profile was observed following exposure of T cells to filaggrin-deficient skin equivalents. Interestingly, TSLP directly stimulated T cell migration exclusively in filaggrin-deficient skin equivalents even in the absence of dendritic cells, indicating a hitherto unknown role of TSLP in the pathogenesis of AD. Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-00670-2 SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Rohn, Isabelle A1 - Raschke, Stefanie A1 - Aschner, Michael A1 - Tuck, Simon A1 - Kuehnelt, Doris A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Treatment of caenorhabditis elegans with small selenium species enhances antioxidant defense systems JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - ScopeSmall selenium (Se) species play a key role in Se metabolism and act as dietary sources of the essential trace element. However, they are redox-active and trigger pro- and antioxidant responses. As health outcomes are strongly species-dependent, species-specific characteristics of Se compounds are tested in vivo. Methods and resultsIn the model organism Caenorhabditis elegans (C. elegans), immediate and sustained effects of selenite, selenomethionine (SeMet), and Se-methylselenocysteine (MeSeCys) are studied regarding their bioavailability, incorporation into proteins, as well as modulation of the cellular redox status. While all tested Se compounds are bioavailable, only SeMet persistently accumulates and is non-specifically incorporated into proteins. However, the protection toward chemically-induced formation of reactive species is independent of the applied Se compound. Increased thioredoxin reductase (TXNRD) activity and changes in mRNA expression levels of antioxidant proteins indicate the activation of cellular defense mechanisms. However, in txnrd-1 deletion mutants, no protective effects of the Se species are observed anymore, which is also reflected by differential gene expression data. ConclusionSe species protect against chemically-induced reactive species formation. The identified immediate and sustained systemic effects of Se species give rise to speculations on possible benefits facing subsequent periods of inadequate Se intake. KW - antioxidant defense systems KW - caenorhabditis elegans KW - selenium KW - oxidative stress KW - selenoproteins Y1 - 2019 U6 - https://doi.org/10.1002/mnfr.201801304 SN - 1613-4125 SN - 1613-4133 VL - 63 IS - 9 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Schweigert, Florian J. A1 - Sehouli, Jalid T1 - Transthyretin, a biomarker for nutritional status and ovarian cancer Y1 - 2005 SN - 0008-5472 ER - TY - JOUR A1 - Henze, Andrea A1 - Espe, Katharina M. A1 - Wanner, Christoph A1 - Krane, Vera A1 - Raila, Jens A1 - Hocher, Berthold A1 - Schweigert, Florian J. A1 - Drechsler, Christiane T1 - Transthyretin predicts cardiovascular outcome in hemodialysis patients with type 2 diabetes JF - Diabetes care N2 - OBJECTIVE-BMI and albumin are commonly accepted parameters to recognize wasting in dialysis patients and are powerful predictors of morbidity and mortality. However, both parameters reveal limitations and may not cover the entire range of patients with wasting. The visceral protein transthyretin (TTR) may be helpful in overcoming the diagnostic and prognostic gap. Therefore, the aim of this study was to assess the association of TTR with morbidity and mortality in hemodialysis patients. RESEARCH DESIGN AND METHODS-The TTR concentration was determined in plasma samples of 1,177 hemodialysis patients with type 2 diabetes. Cox regression analyses were used to determine hazard ratios (HRs) for the risk of cardiovascular end points (CVEs) and mortality according to quartiles of TTR concentration for the total study cohort and the subgroups BMI >= 23 kg/m(2), albumin concentration >= 3.8 g/dL, and a combination of both. RESULTS-A low TTR concentration was associated with an increased risk for CVE for the total study cohort (HR 1.65 [95% CI 1.27-2.14]), patients with BMI >= 23 kg/m(2) (1.70 [1.22-2.37]), albumin >= 3.8 g/dL (1.68 [1.17-2.42]), and the combination of both (1.69 [1.13-2.53]). Additionally, a low TTR concentration predicted mortality for the total study cohort (1.79 [1.43-2.24]) and patients with BMI >= 23 kg/m(2) (1.46 [1.09-1.95]). CONCLUSIONS-The current study demonstrated that TTR is a useful predictor for cardiovascular outcome and mortality in diabetic hemodialysis patients. TTR was particularly useful in patients who were not identified to be at risk by BMI or albumin status. Y1 - 2012 U6 - https://doi.org/10.2337/dc12-0455 SN - 0149-5992 VL - 35 IS - 11 SP - 2365 EP - 2372 PB - American Diabetes Association CY - Alexandria ER - TY - JOUR A1 - Xiong, Chan A1 - Stiboller, Michael A1 - Glabonjat, Ronald A. A1 - Rieger, Jaqueline A1 - Paton, Lhiam A1 - Francesconi, Kevin A. T1 - Transport of arsenolipids to the milk of a nursing mother after consuming salmon fish JF - Journal of trace elements in medicine and biology N2 - Objective: We address two questions relevant to infants' exposure to potentially toxic arsenolipids, namely, are the arsenolipids naturally present in fish transported intact to a mother's milk, and what is the efficiency of this transport. Methods: We investigated the transport of arsenolipids and other arsenic species present in fish to mother's milk by analyzing the milk of a single nursing mother at 15 sampling times over a 3-day period after she had consumed a meal of salmon. Total arsenic values were obtained by elemental mass spectrometry, and arsenic species were measured by HPLC coupled to both elemental and molecular mass spectrometry. Results: Total arsenic increased from background levels (0.1 mu g As kg(-1)) to a peak value of 1.72 lig As kg(-1) eight hours after the fish meal. The pattern for arsenolipids was similar to that of total arsenic, increasing from undetectable background levels (< 0.01 mu g As kg(-1)) to a peak after eight hours of 0.45 mu g As kg(-1). Most of the remaining total arsenic in the milk was accounted for by arsenobetaine. The major arsenolipids in the salmon were arsenic hydrocarbons (AsHCs; 55 % of total arsenolipids), and these compounds were also the dominant arsenolipids in the milk where they contributed over 90 % of the total arsenolipids. Conclusions: Our study has shown that ca 2-3 % of arsenic hydrocarbons, natural constituents of fish, can be directly transferred unchanged to the milk of a nursing mother. In view of the potential neurotoxicity of AsHCs, the effects of these compounds on the brain developmental stage of infants need to be investigated. KW - human milk KW - arsenolipids KW - salmon fish KW - HPLC/ICPMS KW - HPLC/HR-ESMS Y1 - 2020 U6 - https://doi.org/10.1016/j.jtemb.2020.126502 SN - 0946-672X VL - 61 PB - Elsevier CY - München ER - TY - THES A1 - Vossenkuhl, Birgit T1 - Transmission of MRSA along the meat supply chain BT - A methodological concept from farm to fork N2 - Methicillin-resistente Staphylococcus aureus (MRSA) zählen zu den bedeutendsten antibiotikaresistenten Pathogenen, die vor allem in Krankenhäusern aber auch außerhalb von Einrichtungen des Gesundheitswesens weit verbreitet sind. Seit einigen Jahren ist eine neue Generation von MRSA auf dem Vormarsch, die vor allem Nutztierbestände als neue Nische besiedelt. Diese sogenannten Nutztier-assoziierten MRSA wurden wiederholt bei wirtschaftlich bedeutenden Nutztieren sowie daraus gewonnenem Fleisch nachgewiesen. Im Rahmen der vorliegenden Arbeit wurde ein methodischer Ansatz verfolgt, um die Hypothese einer möglichen Übertragung von Nutztier-assoziierten MRSA entlang der Lebensmittelkette vom Tier auf dessen Fleisch zu bestätigen. Angepasst an die Unterschiede in den verfügbaren Daten wurden dafür zwei neue Konzepte erstellt. Zur Analyse der Übertragung von MRSA entlang der Schlachtkette wurde ein mathematisches Modell des Schweineschlachtprozesses entwickelt, welches dazu geeignet ist, den Verlauf der MRSA-Prävalenz entlang der Schlachtkette zu quantifizieren sowie kritische Prozessschritte für eine MRSA-Übertragung zu identifizieren. Anhand von Prävalenzdaten ist es dem Modell möglich, die durchschnittlichen MRSA-Eliminations- und Kontaminationsraten jedes einzelnen Prozessschrittes zu schätzen, die anschließend in eine Monte-Carlo-Simulation einfließen. Im Ergebnis konnte gezeigt werden, dass es generell möglich ist, die MRSA Prävalenz im Laufe des Schlachtprozesses auf ein niedriges finales Niveau zwischen 0,15 bis 1,15% zu reduzieren. Vor allem das Brühen und Abflämmen der Schlachtkörper wurden als kritische Prozesse im Hinblick auf eine MRSA-Dekontamination identifiziert. In Deutschland werden regelmäßig MRSA-Prävalenz und Typisierungsdaten auf allen Stufen der Lebensmittelkette verschiedener Nutztiere erfasst. Um die MRSA-Daten dieser Querschnittstudie hinsichtlich einer möglichen Übertragung entlang der Kette zu analysieren, wurde ein neuer statistischer Ansatz entwickelt. Hierfür wurde eine Chi-Quadrat-Statistik mit der Berechnung des Czekanowski-Ähnlichkeitsindex kombiniert, um Unterschiede in der Verteilung stammspezifischer Eigenschaften zwischen MRSA aus dem Stall, von Karkassen nach der Schlachtung und aus Fleisch im Einzelhandel zu quantifizieren. Die Methode wurde am Beispiel der Putenfleischkette implementiert und zudem bei der Analyse der Kalbfleischkette angewendet. Die durchgehend hohen Ähnlichkeitswerte zwischen den einzelnen Proben weisen auf eine mögliche Übertragung von MRSA entlang der Lebensmittelkette hin. Die erarbeiteten Methoden sind nicht spezifisch bezüglich Prozessketten und Pathogenen. Sie bieten somit einen großen Anwendungsbereich und erweitern das Methodenspektrum zur Bewertung bakterieller Übertragungswege. N2 - Methicillin resistant Staphylococcus aureus (MRSA) is one of the most important antibiotic-resistant pathogens in hospitals and the community. Recently, a new generation of MRSA, the so called livestock associated (LA) MRSA, has emerged occupying food producing animals as a new niche. LA-MRSA can be regularly isolated from economically important live-stock species including corresponding meats. The present thesis takes a methodological approach to confirm the hypothesis that LA-MRSA are transmitted along the pork, poultry and beef production chain from animals at farm to meat on consumers` table. Therefore two new concepts were developed, adapted to differing data sets. A mathematical model of the pig slaughter process was developed which simulates the change in MRSA carcass prevalence during slaughter with special emphasis on identifying critical process steps for MRSA transmission. Based on prevalences as sole input variables the model framework is able to estimate the average value range of both the MRSA elimination and contamination rate of each of the slaughter steps. These rates are then used to set up a Monte Carlo simulation of the slaughter process chain. The model concludes that regardless of the initial extent of MRSA contamination low outcome prevalences ranging between 0.15 and 1.15 % can be achieved among carcasses at the end of slaughter. Thus, the model demonstrates that the standard procedure of pig slaughtering in principle includes process steps with the capacity to limit MRSA cross contamination. Scalding and singeing were identified as critical process steps for a significant reduction of superficial MRSA contamination. In the course of the German national monitoring program for zoonotic agents MRSA prevalence and typing data are regularly collected covering the key steps of different food production chains. A new statistical approach has been proposed for analyzing this cross sectional set of MRSA data with regard to show potential farm to fork transmission. For this purpose, chi squared statistics was combined with the calculation of the Czekanowski similarity index to compare the distributions of strain specific characteristics between the samples from farm, carcasses after slaughter and meat at retail. The method was implemented on the turkey and veal production chains and the consistently high degrees of similarity which have been revealed between all sample pairs indicate MRSA transmission along the chain. As the proposed methods are not specific to process chains or pathogens they offer a broad field of application and extend the spectrum of methods for bacterial transmission assessment. KW - MRSA KW - Antibiotikaresistenz KW - Modell KW - Lebensmittelkette KW - Übertragung KW - MRSA KW - Resistance KW - Model KW - Food Chain KW - Transmission Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-85918 ER - TY - JOUR A1 - Eckel, Nathalie A1 - Li, Yanping A1 - Kuxhaus, Olga A1 - Stefan, Norbert A1 - Hu, Frank B. A1 - Schulze, Matthias Bernd T1 - Transition from metabolic healthy to unhealthy phenotypes and association with cardiovascular disease risk across BMI categories in 90 257 women (the Nurses' Health Study) BT - 30 year follow-up from a prospective cohort study JF - The lancet diabetes & endocrinology N2 - Background Cardiovascular disease risk among individuals across different categories of BMI might depend on their metabolic health. It remains unclear to what extent metabolic health status changes over time and whether this affects cardiovascular disease risk. In this study, we aimed to examine the association between metabolic health and its change over time and cardiovascular disease risk across BMI categories. Findings During 2 127 391 person-years of follow-up with a median follow-up of 24 years, we documented 6306 cases of cardiovascular disease including 3304 myocardial infarction cases and 3080 strokes. Cardiovascular disease risk of women with metabolically healthy obesity was increased compared with women with metabolically healthy normal weight (HR 1.39, 95% CI 1.15-1.68), but risk was considerably higher in women with metabolically unhealthy normal weight (2.43, 2.19-2.68), overweight (2.61, 2.36-2.89) and obesity (3.15, 2.83-3.50). The majority of metabolically healthy women converted to unhealthy phenotypes (2555 [84%] of 3027 women with obesity, 22 215 [68%] of 32 882 women with normal-weight after 20 years). Women who maintained metabolically healthy obesity during follow-up were still at a higher cardiovascular disease risk compared with women with stable healthy normal weight (HR 1.57, 1.03-2.38), yet this risk was lower than for initially metabolically healthy women who converted to an unhealthy phenotype (normal-weight 1.90, 1.66-2.17 vs obesity 2.74, 2.30-3.27). Particularly incident diabetes and hypertension increased the risk among women with initial metabolic health. Interpretation Even when metabolic health is maintained during long periods of time, obesity remains a risk factor for cardiovascular disease. However, risks are highest for metabolically unhealthy women across all BMI categories. A large proportion of metabolically healthy women converted to an unhealthy phenotype over time across all BMI categories, which is associated with an increased cardiovascular disease risk. Copyright (C) 2018 Elsevier Ltd. All rights reserved. Y1 - 2018 U6 - https://doi.org/10.1016/S2213-8587(18)30137-2 SN - 2213-8587 VL - 6 IS - 9 SP - 714 EP - 724 PB - Elsevier CY - New York ER - TY - GEN A1 - Plank, Roswitha A1 - Yealland, Guy A1 - Miceli, Enrico A1 - Cunha, Dulce Lima A1 - Graff, Patrick A1 - Thomforde, Sari A1 - Gruber, Robert A1 - Moosbrugger-Martinz, Verena A1 - Eckl, Katja A1 - Calderon, Marcelo A1 - Hennies, Hans Christian A1 - Hedtrich, Sarah T1 - Transglutaminase 1 Replacement Therapy Successfully Mitigates the Autosomal Recessive Congenital Ichthyosis Phenotype in Full-Thickness Skin Disease Equivalents T2 - The journal of investigative dermatology Y1 - 2019 U6 - https://doi.org/10.1016/j.jid.2018.11.002 SN - 0022-202X SN - 1523-1747 VL - 139 IS - 5 SP - 1191 EP - 1195 PB - Elsevier CY - New York ER - TY - THES A1 - Schoefer, Lilian T1 - Transformation of flavonoids by bacteria from the human intestinal tract Y1 - 2002 ER - TY - JOUR A1 - Schweigert, Florian J. A1 - Steinhagen, Beate A1 - Trüpschuch, Annett A1 - Siemann, A. A1 - Büscher, Ulrich A1 - Dudenhausen, Joachim W. T1 - Transfer of carotenoids, alfa-tocopherol and retinol from plasma into follicular fluid in women Y1 - 2000 ER - TY - JOUR A1 - Szanto, Attila A1 - Benko, Szilvia A1 - Szatmari, István A1 - Balint, Balint L. A1 - Furtos, Ibolya A1 - Ruehl, Ralph A1 - Molnar, Sandor A1 - Csiba, Laszlo A1 - Garuti, Rita A1 - Calandra, Sebastiano A1 - Larsson, Hanna A1 - Diczfalusy, Ulf A1 - Nagy, Laszlo T1 - Transcriptional regulation of human CYP27 integrates retinoid, peroxisome proliferator-activated receptor, and liver X receptor signaling in macrophages N2 - 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 Y1 - 2004 SN - 0270-7306 ER - TY - JOUR A1 - Marschall, Talke Anu A1 - Kroepfl, Nina A1 - Jensen, Kenneth Bendix A1 - Bornhorst, Julia A1 - Meermann, B. A1 - Kühnelt, Doris A1 - Schwerdtle, Tanja T1 - Tracing cytotoxic effects of small organic Se species in human liver cells back to total cellular Se and Se metabolites JF - Metallomics N2 - Small selenium (Se) species play a major role in the metabolism, excretion and dietary supply of the essential trace element selenium. Human cells provide a valuable tool for investigating currently unresolved issues on the cellular mechanisms of Se toxicity and metabolism. In this study, we developed two isotope dilution inductively coupled plasma tandem-mass spectrometry based methods and applied them to human hepatoma cells (HepG2) in order to quantitatively elucidate total cellular Se concentrations and cellular Se species transformations in relation to the cytotoxic effects of four small organic Se species. Species-and incubation time-dependent results were obtained: the two major urinary excretion metabolites trimethylselenonium (TMSe) and methyl-2-acetamido-2-deoxy-1-seleno-beta- D-galactopyranoside (SeSugar 1) were taken up by the HepG2 cells in an unmodified manner and did not considerably contribute to the Se pool. In contrast, Se-methylselenocysteine (MeSeCys) and selenomethionine (SeMet) were taken up in higher amounts, they were largely incorporated by the cells (most likely into proteins) and metabolized to other small Se species. Two new metabolites of MeSeCys, namely gamma-glutamyl-Se-methylselenocysteine and Se-methylselenoglutathione, were identified by means of HPLC-electrospray-ionization-Orbitrap-MS. They are certainly involved in the (de-) toxification modes of Se metabolism and require further investigation. Y1 - 2017 U6 - https://doi.org/10.1039/c6mt00300a SN - 1756-5901 SN - 1756-591X VL - 9 SP - 268 EP - 277 PB - Royal Society of Chemistry CY - Cambridge ER - TY - CHAP A1 - Wandt, Viktoria Klara Veronika A1 - Winkelbeiner, Nicola A1 - Loßow, Kristina A1 - Kopp, Johannes A1 - Simon, Luise A1 - Ebert, Franziska A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja T1 - Trace elements, ageing, and sex. Impact on genome stability BT - Abstracts of the 87th Annual Meeting of the German Society for Experimental and Clinical Pharmacology and Toxicology (DGPT) with contribution of the Arbeitsgemeinschaft für Angewandte Humanpharmakologie e. V. (AGAH) T2 - Naunyn-Schmiedeberg's archives of pharmacology Y1 - 2021 U6 - https://doi.org/10.1007/s00210-021-02066-6 SN - 0028-1298 SN - 1432-1912 VL - 394 IS - Suppl. 1 SP - S13 EP - S13 PB - Springer CY - Berlin ; Heidelberg ER - TY - THES A1 - Wandt, Viktoria Klara Veronika T1 - Trace elements, ageing, and sex BT - impact on genome stability maintenance Y1 - 2021 ER - TY - THES A1 - Baeseler, Jessica T1 - Trace element effects on longevity and neurodegeneration with focus on C. elegans T1 - Effekte von Spurenelementen auf die Lebensdauer und Neurodegeneration mit Fokus auf C. elegans N2 - The trace elements zinc and manganese are essential for human health, especially due to their enzymatic and protein stabilizing functions. If these elements are ingested in amounts exceeding the requirements, regulatory processes for maintaining their physiological concentrations (homeostasis) can be disturbed. Those homeostatic dysregulations can cause severe health effects including the emergence of neurodegenerative disorders such as Parkinson’s disease (PD). The concentrations of essential trace elements also change during the aging process. However, the relations of cause and consequence between increased manganese and zinc uptake and its influence on the aging process and the emergence of the aging-associated PD are still rarely understood. This doctoral thesis therefore aimed to investigate the influence of a nutritive zinc and/or manganese oversupply on the metal homeostasis during the aging process. For that, the model organism Caenorhabditis elegans (C. elegans) was applied. This nematode suits well as an aging and PD model due to properties such as its short life cycle and its completely sequenced, genetically amenable genome. Different protocols for the propagation of zinc- and/or manganese-supplemented young, middle-aged and aged C. elegans were established. Therefore, wildtypes, as well as genetically modified worm strains modeling inheritable forms of parkinsonism were applied. To identify homeostatic and neurological alterations, the nematodes were investigated with different methods including the analysis of total metal contents via inductively-coupled plasma tandem mass spectrometry, a specific probe-based method for quantifying labile zinc, survival assays, gene expression analysis as well as fluorescence microscopy for the identification and quantification of dopaminergic neurodegeneration.. During aging, the levels of iron, as well as zinc and manganese increased.. Furthermore, the simultaneous oversupply with zinc and manganese increased the total zinc and manganese contents to a higher extend than the single metal supplementation. In this relation the C. elegans metallothionein 1 (MTL-1) was identified as an important regulator of metal homeostasis. The total zinc content and the concentration of labile zinc were age-dependently, but differently regulated. This elucidates the importance of distinguishing these parameters as two independent biomarkers for the zinc status. Not the metal oversupply, but aging increased the levels of dopaminergic neurodegeneration. Additionally, nearly all these results yielded differences in the aging-dependent regulation of trace element homeostasis between wildtypes and PD models. This confirms that an increased zinc and manganese intake can influence the aging process as well as parkinsonism by altering homeostasis although the underlying mechanisms need to be clarified in further studies. N2 - Die Spurenelemente Zink und Mangan sind vor allem aufgrund ihrer enzymatischen und Protein-stabilisierenden Funktionen essentiell für die menschliche Gesundheit. Werden sie allerdings in Mengen aufgenommen, die den Bedarf übersteigen, können regulatorische Prozesse für die Aufrechterhaltung physiologischer Konzentrationen dieser Metalle (Homöostase) aus dem Gleichgewicht geraten. Das kann ernsthafte gesundheitliche Konsequenzen nach sich ziehen, unter anderem die Entstehung neurodegenerativer Krankheiten, wie zum Beispiel der Parkinson’schen Erkrankung. Auch während des Alterungsprozesses verändern sich die Gehalte an lebensnotwendigen Spurenelementen im Körper. Jedoch sind die Zusammenhänge zwischen Ursache und Wirkung einer erhöhten Aufnahme an Zink und Mangan und deren Einfluss auf den Alterungsprozess und die Entstehung der altersassoziierten Parkinson’schen Erkrankung bisher nur unzureichend verstanden. Im Rahmen dieser Doktorarbeit wurde deshalb der Einfluss einer nutritiven Zink- und/oder Manganüberversorgung auf die Metallhomöostase während der Alterung untersucht. Dazu wurde Caenorhabditis elegans (C. elegans) als Modellorganismus verwendet. Diese Fadenwürmer eignen sich aufgrund verschiedener Eigenschaften, wie einem kurzen Lebenszyklus und einem komplett sequenzierten und leicht manipulierbarem Genom, hervorragend als Alters- und Parkinson-Modelle. Es wurden verschiedene Protokolle etabliert, die die Anzucht von Zink- und/oder Mangan-supplementierten jungen, mittelalten bzw. gealterten C. elegans erlaubten. Neben Wildtypen wurden auch Wurmstämme untersucht, die genetische Modifikationen aufweisen, die mit vererbbaren Formen des Parkinsonismus assoziiert werden können. Die Würmer wurden mithilfe verschiedener Methoden, wie der analytischen Bestimmung des Gesamtmetallgehaltes mittels Massenspektrometrie mit induktiv-gekoppeltem Plasma, einer Sonden-spezifischen Methode zur Bestimmung von freiem Zink, Letalitätsassays, Genexpressionsanalysen und der Fluoreszenz-mikroskopischen Untersuchung der dopaminergen Neurodegeneration auf verschiedene Parameter untersucht, die Aufschluss über homöostatische und neurologische Veränderungen geben. Es wurde eine altersbedingte Zunahme von Eisen, sowie Zink und Mangan in den Würmern beobachtet. Weiterhin stellte sich heraus, dass vor allem die simultane Überversorgung mit Zink und Mangan den Gesamtmetallgehalt dieser Metalle in C. elegans in einem Maß steigerte, das das der Einzelmetallsupplementierung überstieg. Dabei konnte vor allem das C. elegans Metallothionein 1 (MTL-1) als wichtiger Faktor in der Regulation der Metallhomöostase identifiziert werden. Außerdem wurde die Wichtigkeit verdeutlicht, zwischen dem Gesamtzinkgehalt und der Konzentration an freiem Zink als Biomarkern für den Zinkstatus eines Organismus zu unterscheiden. Beide Parameter wurden altersabhängig unterschiedlich reguliert. Im Gegensatz zur Alterung, wurde durch die Überversorgung mit Metallen keine zusätzliche Schädigung der dopaminergen Neuronen beobachtet. In nahezu all diesen Ergebnissen verdeutlichten sich weiterhin Unterschiede in der altersabhängigen Regulation der Spurenelementhomöostase zwischen Wildtypen und Parkinson-Modellen. Dies bestätigt die Annahme, dass sich eine erhöhte Aufnahme von Mangan und Zink durch die Beeinflussung der Homöostase sowohl auf die Alterung, als auch den Parkinsonismus auswirken kann, jedoch müssen die mechanistischen Grundlagen dessen in zukünftigen Studien aufgeklärt werden. KW - Caenorhabditis elegans KW - aging KW - trace element KW - zinc KW - manganese KW - Caenorhabditis elegans KW - Alterung KW - Spurenelement KW - Zink KW - Mangan Y1 - 2021 ER - TY - THES A1 - Ziemann, Vanessa T1 - Toxische Effekte von Arsenolipiden in humanen Kulturzellen und Caenorhabditis elegans Y1 - 2020 ER - TY - THES A1 - Schröder, Insa Sigrid T1 - Toxikologische Untersuchungen von Isothiocyanat-Proteinderivaten Y1 - 1999 ER -