TY  - JOUR
A1  - Norrmen, Camilla
A1  - Figlia, Gianluca
A1  - Lebrun-Julien, Frederic
A1  - Pereira, Jorge A.
A1  - Trötzmüller, Martin
A1  - Köfeler, Harald C.
A1  - Rantanen, Ville
A1  - Wessig, Carsten
A1  - van Deijk, Anne-Lieke F.
A1  - Smit, August B.
A1  - Verheijen, Mark H. G.
A1  - Rüegg, Markus A.
A1  - Hall, Michael N.
A1  - Suter, Ueli
T1  - mTORC1 Controls PNS Myelination along the mTORC1-RXR gamma-SREBP-Lipid Biosynthesis Axis in Schwann Cells
JF  - Cell Reports
N2  - Myelin formation during peripheral nervous system (PNS) development, and reformation after injury and in disease, requires multiple intrinsic and extrinsic signals. Akt/mTOR signaling has emerged as a major player involved, but the molecular mechanisms and downstream effectors are virtually unknown. Here, we have used Schwann-cell-specific conditional gene ablation of raptor and rictor, which encode essential components of the mTOR complexes 1 (mTORC1) and 2 (mTORC2), respectively, to demonstrate that mTORC1 controls PNS myelination during development. In this process, mTORC1 regulates lipid biosynthesis via sterol regulatory element-binding proteins (SREBPs). This course of action is mediated by the nuclear receptor RXRg, which transcriptionally regulates SREBP1c downstream of mTORC1. Absence of mTORC1 causes delayed myelination initiation as well as hypomyelination, together with abnormal lipid composition and decreased nerve conduction velocity. Thus, we have identified the mTORC1-RXR gamma-SREBP axis controlling lipid biosynthesis as a major contributor to proper peripheral nerve function.
KW  - axonal integrity
KW  - peripheral nervous-system
KW  - COMPLEX 1
KW  - rat hepatocytes
KW  - SREBP
KW  - mice
KW  - growth
KW  - protein
KW  - element
KW  - CNS Myelination
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114847
SN  - 2211-1247
VL  - 9
IS  - 2
ER  - 
TY  - JOUR
A1  - Elabyad, Ibrahim A.
A1  - Terekhov, Maxim
A1  - Lohr, David
A1  - Stefanescu, Maria R.
A1  - Baltes, Steffen
A1  - Schreiber, Laura M.
T1  - A Novel Mono-surface Antisymmetric 8Tx/16Rx Coil Array for Parallel Transmit Cardiac MRI in Pigs at 7T
JF  - Scientific Reports
N2  - A novel mono-surface antisymmetric 16-element transmit/receive (Tx/Rx) coil array was designed, simulated, constructed, and tested for cardiac magnetic resonance imaging (cMRI) in pigs at 7T. The cardiac array comprised of a mono-surface 16-loops with two central elements arranged antisymmetrically and flanked by seven elements on either side. The array was configured for parallel transmit (pTx) mode to have an eight channel transmit and 16-channel receive (8Tx/16Rx) coil array. Electromagnetic (EM) simulations, bench-top measurements, phantom, and MRI experiments with two pig cadavers (68 and 46 kg) were performed. Finally, the coil was used in pilot in-vivo measurements with a 60 kg pig. Flip angle (FA), geometry factor (g-factor), signal-to-noise ratio (SNR) maps, and high-resolution cardiac images were acquired with an in-plane resolution of 0.6 mm x 0.6 mm (in-vivo) and 0.3 mm x 0.3 mm (ex-vivo). The mean g-factor over the heart was 1.26 (R = 6). Static phase B-1(+) shimming in a pig body phantom with the optimal phase vectors makes possible to improve the B-1(+) homogeneity by factor > 2 and transmit efficiency by factor > 3 compared to zero phases (before RF shimming). Parallel imaging performed in the in-vivo measurements demonstrated well preserved diagnostic quality of the resulting images at acceleration factors up to R = 6. The described hardware design can be adapted for arrays optimized for animals and humans with a larger number of elements (32-64) while maintaining good decoupling for various MRI applications at UHF (e.g., cardiac, head, and spine).
KW  - high-field MRI
KW  - stepped impedance resonators
KW  - magnetic resoncance
KW  - transceiver array
KW  - SAR safety
KW  - design
KW  - body
KW  - element
KW  - antenna
KW  - images
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229436
VL  - 10
IS  - 1
ER  -