TY  - JOUR
A1  - Zeller, Mario
A1  - Müller, Alexander
A1  - Gutberlet, Marcel
A1  - Nichols, Thomas
A1  - Hahn, Dietbert
A1  - Köstler, Herbert
A1  - Bartsch, Andreas J.
T1  - Boosting BOLD fMRI by K-Space Density Weighted Echo Planar Imaging
JF  - PLoS ONE
N2  - Functional magnetic resonance imaging (fMRI) has become a powerful and influential method to non-invasively study neuronal brain activity. For this purpose, the blood oxygenation level-dependent (BOLD) effect is most widely used. T2* weighted echo planar imaging (EPI) is BOLD sensitive and the prevailing fMRI acquisition technique. Here, we present an alternative to its standard Cartesian recordings, i.e. k-space density weighted EPI, which is expected to increase the signal-to-noise ratio in fMRI data. Based on in vitro and in vivo pilot measurements, we show that fMRI by k-space density weighted EPI is feasible and that this new acquisition technique in fact boosted spatial and temporal SNR as well as the detection of local fMRI activations. Spatial resolution, spatial response function and echo time were identical for density weighted and conventional Cartesian EPI. The signal-to-noise ratio gain of density weighting can improve activation detection and has the potential to further increase the sensitivity of fMRI investigations.
KW  - data acquisition
KW  - density
KW  - echo planar imaging
KW  - functional magnetic resonance imaging
KW  - imaging techniques
KW  - matched filters
KW  - signal filtering
KW  - statistical data
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97233
ER  - 
TY  - JOUR
A1  - van Dinther, Maarten
A1  - Zhang, Juan
A1  - Weidauer, Stella E.
A1  - Boschert, Verena
A1  - Muth, Eva-Maria
A1  - Knappik, Achim
A1  - de Gorter, David J. J.
A1  - van Kasteren, Puck B.
A1  - Frisch, Christian
A1  - Müller, Thomas D.
A1  - ten Dijke, Peter
T1  - Anti-Sclerostin Antibody Inhibits Internalization of Sclerostin and Sclerostin-Mediated Antagonism of Wnt/LRP6 Signaling
JF  - PLoS ONE
N2  - Sclerosteosis is a rare high bone mass disease that is caused by inactivating mutations in the SOST gene. Its gene product, Sclerostin, is a key negative regulator of bone formation and might therefore serve as a target for the anabolic treatment of osteoporosis. The exact molecular mechanism by which Sclerostin exerts its antagonistic effects on Wnt signaling in bone forming osteoblasts remains unclear. Here we show that Wnt3a-induced transcriptional responses and induction of alkaline phosphatase activity, an early marker of osteoblast differentiation, require the Wnt co-receptors LRP5 and LRP6. Unlike Dickkopf1 (DKK1), Sclerostin does not inhibit Wnt-3a-induced phosphorylation of LRP5 at serine 1503 or LRP6 at serine 1490. Affinity labeling of cell surface proteins with \([^{125} I]\) Sclerostin identified LRP6 as the main specific Sclerostin receptor in multiple mesenchymal cell lines. When cells were challenged with Sclerostin fused to recombinant green fluorescent protein (GFP) this was internalized, likely via a Clathrin-dependent process, and subsequently degraded in a temperature and proteasome-dependent manner. Ectopic expression of LRP6 greatly enhanced binding and cellular uptake of Sclerostin-GFP, which was reduced by the addition of an excess of non-GFP-fused Sclerostin. Finally, an anti-Sclerostin antibody inhibited the internalization of Sclerostin-GFP and binding of Sclerostin to LRP6. Moreover, this antibody attenuated the antagonistic activity of Sclerostin on canonical Wnt-induced responses.
KW  - gene
KW  - rat model
KW  - Dickkopf proteins
KW  - postmenopausal osteoporosis
KW  - increases bone-formation
KW  - WNT
KW  - LRP6
KW  - density
KW  - receptor
KW  - ligand
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130981
VL  - 8
IS  - 4
ER  - 
TY  - JOUR
A1  - Breeze, Tom D.
A1  - Vaissiere, Bernhard E.
A1  - Bommarco, Riccardo
A1  - Petanidou, Theodora
A1  - Seraphides, Nicos
A1  - Kozak, Lajos
A1  - Scheper, Jeroen
A1  - Biesmeijer, Jacobus C.
A1  - Kleijn, David
A1  - Gyldenkærne, Steen
A1  - Moretti, Marco
A1  - Holzschuh, Andrea
A1  - Steffan-Dewenter, Ingolf
A1  - Stout, Jane C.
A1  - Pärtel, Meelis
A1  - Zobel, Martin
A1  - Potts, Simon G.
T1  - Agricultural Policies Exacerbate Honeybee Pollination Service Supply-Demand Mismatches Across Europe
JF  - PLOS ONE
N2  - Declines in insect pollinators across Europe have raised concerns about the supply of pollination services to agriculture. Simultaneously, EU agricultural and biofuel policies have encouraged substantial growth in the cultivated area of insect pollinated crops across the continent. Using data from 41 European countries, this study demonstrates that the recommended number of honeybees required to provide crop pollination across Europe has risen 4.9 times as fast as honeybee stocks between 2005 and 2010. Consequently, honeybee stocks were insufficient to supply >90% of demands in 22 countries studied. These findings raise concerns about the capacity of many countries to cope with major losses of wild pollinators and highlight numerous critical gaps in current understanding of pollination service supplies and demands, pointing to a pressing need for further research into this issue.
KW  - economy services
KW  - fruit set
KW  - sequential introduction
KW  - enhance
KW  - biodiversity
KW  - abundance
KW  - declines
KW  - crops
KW  - colonies
KW  - density
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117692
SN  - 1932-6203
VL  - 9
IS  - 1
ER  -