151 research outputs found

    Die Raucherbiographie des Hausarztes und sein Interventionsverhalten - Gibt es einen Zusammenhang?

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    Das eigene Rauchverhalten und die Einstellung des Hausarztes zur Raucherentwöhnung stellen wichtige Grundlagen für eine erfolgreiche Intervention dar. Diese These wurde mit Hilfe von Daten aus der SNICAS-Studie untersucht. Ergebnis: Rauchen ist unter Hausärzten ein verbreitetes Phänomen und die Einstellung von aktuell rauchenden Hausärzten unterscheidet sich sich in einigen Bereichen deutlich von den Ex-Rauchern bzw. Nie- Rauchern

    Rab13 regulates PKA signaling during tight junction assembly

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    The GTPase Rab13 regulates the assembly of functional epithelial tight junctions (TJs) through a yet unknown mechanism. Here, we show that expression of the GTP-bound form of Rab13 inhibits PKA-dependent phosphorylation and TJ recruitment of the vasodilator-stimulated phosphoprotein, an actin remodelling protein. We demonstrate that Rab13GTP directly binds to PKA and inhibits its activity. Interestingly, activation of PKA abrogates the inhibitory effect of Rab13 on the recruitment of vasodilator-stimulated phosphoprotein, ZO-1, and claudin1 to cell–cell junctions. Rab13 is, therefore, the first GTPase that controls PKA activity and provides an unexpected link between PKA signaling and the dynamics of TJ assembly

    The Drosophila SH2B Family Adaptor Lnk Acts in Parallel to Chico in the Insulin Signaling Pathway

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    Insulin/insulin-like growth factor signaling (IIS) plays a pivotal role in the regulation of growth at the cellular and the organismal level during animal development. Flies with impaired IIS are developmentally delayed and small due to fewer and smaller cells. In the search for new growth-promoting genes, we identified mutations in the gene encoding Lnk, the single fly member of the SH2B family of adaptor molecules. Flies lacking lnk function are viable but severely reduced in size. Furthermore, lnk mutants display phenotypes reminiscent of reduced IIS, such as developmental delay, female sterility, and accumulation of lipids. Genetic epistasis analysis places lnk downstream of the insulin receptor (InR) and upstream of phosphoinositide 3-kinase (PI3K) in the IIS cascade, at the same level as chico (encoding the single fly insulin receptor substrate [IRS] homolog). Both chico and lnk mutant larvae display a similar reduction in IIS activity as judged by the localization of a PIP3 reporter and the phosphorylation of protein kinase B (PKB). Furthermore, chico; lnk double mutants are synthetically lethal, suggesting that Chico and Lnk fulfill independent but partially redundant functions in the activation of PI3K upon InR stimulation

    Identifying and understanding long-distance travel demand by combining official transport statistics and survey data

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    While much is known about everyday travel of the German population, long-distance travel is still underreported. The main data source, the national travel survey “Mobility in Germany (MiD)”, cannot simply be used to describe the demand: complex extrapolations and complementary data are necessary to obtain a consistent picture. The presented approach of ‘data fusion’ integrates different data sources to provide the overall long-distance travel demand. The result reveals that almost half of the total transport performance of the residential population in Germany (46 % of passenger kilometers) is accounted for by trips of at least 100 km (one-way distance)

    Transport Function of the Renal Type IIa Na+/Pi Cotransporter Is Codetermined by Residues in Two Opposing Linker Regions

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    Two highly similar regions in the predicted first intracellular (ICL-1) and third extracellular loop (ECL-3) of the type IIa Na+/Pi cotransporter (NaPi-IIa) have been shown previously to contain functionally important sites by applying the substituted cysteine accessibility method (SCAM). Incubation in methanethiosulfonate (MTS) reagents of mutants that contain novel cysteines in both loops led to full inhibition of cotransport activity. To elucidate further the role these regions play in defining the transport mechanism, a double mutant (A203C-S460C) was constructed with novel cysteines in each region. The effect of cysteine modification by different MTS reagents on two electrogenic transport modes (leak and cotransport) was investigated. MTSEA (2-aminoethyl MTS hydrobromide) and MTSES (MTS ethylsulfonate) led to full inhibition of cotransport and increased the leak, whereas incubation in MTSET (2-[trimethylammonium]ethyl MTS bromide) inhibited only cotransport. The behavior of other double mutants with a cysteine retained at one site and hydrophobic or hydrophilic residues substituted at the other site, indicated that most likely only Cys-460 was modifiable, but the residue at Ala-203 was critical for conferring the leak and cotransport mode behavior. Substrate interaction with the double mutant was unaffected by MTS exposure as the apparent Pi and Na+ affinities for Pi-induced currents and respective activation functions were unchanged after cysteine modification. This suggested that the modified site did not interfere with substrate recognition/binding, but prevents translocation of the fully loaded carrier. The time-dependency of cotransport loss and leak growth during modification of the double cysteine mutant was reciprocal, which suggested that the modified site is a kinetic codeterminant of both transport modes. The behavior is consistent with a kinetic model for NaPi-IIa that predicts mutual exclusiveness of both transport modes. Together, these findings suggest that parts of the opposing linker regions are associated with the NaPi-IIa transport pathway

    The renal type IIa Na/Pi cotransporter: Structure-function relationships

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    The type IIa Na/Pi cotransporter mediates proximal tubular brush-border membrane secondary active phosphate (Pi) flux. It is rate limiting in tubular Pi reabsorption and, thus, a final target in many physiological and pathophysiological situations of altered renal Pi handling (1-4). In the present short review, we will briefly summarize our current knowledge about the transport mechanism (cycle) as well as particular regions of the transporter protein ("molecular domains”) that potentially determine transport characteristic

    Optical gating with organic building blocks : A quantitative model for the fluorescence modulation of photochromic perylene bisimide dithienylcyclopentene triads

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    We investigated the capability of molecular triads, consisting of two strong fluorophores that were covalently linked to a photochromic molecule, for optical gating. Therefore we monitored the fluorescence intensity of the fluorophores as a function of the isomeric state of the photoswitch. From the analysis of our data we develop a kinetic model that allows us to predict quantitatively the degree of the fluorescence modulation as a function of the mutual intensities of the lasers that are used to induce the fluorescence and the switching of the photochromic unit. We find that the achievable contrast for the modulation of the fluorescence depends mainly on the intensity ratio of the two light beams and appears to be very robust against absolute changes of these intensities. The latter result provides valuable information for the development of all-optical circuits which would require to handle different signal strengths for the input and output levels

    Imp-L2, a putative homolog of vertebrate IGF-binding protein 7, counteracts insulin signaling in Drosophila and is essential for starvation resistance

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    <p>Abstract</p> <p>Background</p> <p>Insulin and insulin-like growth factors (IGFs) signal through a highly conserved pathway and control growth and metabolism in both vertebrates and invertebrates. In mammals, insulin-like growth factor binding proteins (IGFBPs) bind IGFs with high affinity and modulate their mitogenic, anti-apoptotic and metabolic actions, but no functional homologs have been identified in invertebrates so far.</p> <p>Results</p> <p>Here, we show that the secreted Imaginal morphogenesis protein-Late 2 (Imp-L2) binds <it>Drosophila </it>insulin-like peptide 2 (Dilp2) and inhibits growth non-autonomously. Whereas over-expressing <it>Imp-L2 </it>strongly reduces size, loss of <it>Imp-L2 </it>function results in an increased body size. <it>Imp-L2 </it>is both necessary and sufficient to compensate Dilp2-induced hyperinsulinemia <it>in vivo</it>. Under starvation conditions, <it>Imp-L2 </it>is essential for proper dampening of insulin signaling and larval survival.</p> <p>Conclusion</p> <p>Imp-L2, the first functionally characterized insulin-binding protein in invertebrates, serves as a nutritionally controlled suppressor of insulin-mediated growth in <it>Drosophila</it>. Given that Imp-L2 and the human tumor suppressor IGFBP-7 show sequence homology in their carboxy-terminal immunoglobulin-like domains, we suggest that their common precursor was an ancestral insulin-binding protein.</p

    Platelet G i protein Gα i2 is an essential mediator of thrombo-inflammatory organ damage in mice

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    Platelets are crucial for hemostasis and thrombosis and exacerbate tissue injury following ischemia and reperfusion. Important regulators of platelet function are G proteins controlled by seven transmembrane receptors. The Gi protein Gα(i2) mediates platelet activation in vitro, but its in vivo role in hemostasis, arterial thrombosis, and postischemic infarct progression remains to be determined. Here we show that mice lacking Gα(i2) exhibit prolonged tail-bleeding times and markedly impaired thrombus formation and stability in different models of arterial thrombosis. We thus generated mice selectively lacking Gα(i2) in megakaryocytes and platelets (Gna(i2)(fl/fl)/PF4-Cre mice) and found bleeding defects comparable to those in global Gα(i2)-deficient mice. To examine the impact of platelet Gα(i2) in postischemic thrombo-inflammatory infarct progression, Gna(i2)(fl/fl)/PF4-Cre mice were subjected to experimental models of cerebral and myocardial ischemia/reperfusion injury. In the model of transient middle cerebral artery occlusion stroke Gna(i2)(fl/fl)/PF4-Cre mice developed significantly smaller brain infarcts and fewer neurological deficits than littermate controls. Following myocardial ischemia, Gna(i2)(fl/fl)/PF4-Cre mice showed dramatically reduced reperfusion injury which correlated with diminished formation of the ADP-dependent platelet neutrophil complex. In conclusion, our data provide definitive evidence that platelet Gα(i2) not only controls hemostatic and thrombotic responses but also is critical for the development of ischemia/reperfusion injury in vivo.Fil: Devanathan, Vasudharani. University of Tübingen; AlemaniaFil: Hagedorn, Ina. University Hospital; AlemaniaFil: Köhler, David. University of Tübingen; AlemaniaFil: Pexa, Katja. Universitat Dusseldorf; AlemaniaFil: Cherpokova, Deya. University Hospital; AlemaniaFil: Kraft, Peter. Universität Würzburg; AlemaniaFil: Singh, Madhurendra. Universitat Dusseldorf; AlemaniaFil: Rosenberger, Peter. University of Tübingen; AlemaniaFil: Stoll, Guido. Universität Würzburg; AlemaniaFil: Birnbaumer, Lutz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Research Triangle Park; AlemaniaFil: Piekorz, Roland P.. Universitat Dusseldorf; AlemaniaFil: Beer-Hammer, Sandra. University of Tübingen; AlemaniaFil: Nieswandt, Bernhard. University Hospital; AlemaniaFil: Nürnberg, Bernd. University of Tübingen; Alemani
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