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[en] Gd-DTPA is the 1st paramagnetic contrast agent approved for clinical use in cranial and spinal MRI in the FRG, USA, Japan and several other countries. After submission 13439 patients were enrolled in standardized protocolled clinical trials. The observed adverse drug reactions (ADRs) after i.v. injection of Gd-DTPA were comparable to those after admini-stration of iodinated non-ionic roentgen contrast media (CM). However, the overall incidence of ADRs after intravenous injection of 0.1 or 0.2 mmol/kg body weight Gd-DTPA was found to be even lower. Adverse events were observed in only 1.46 percent of the patients - or 1.14 if localized warmth is excluded. None of the was critical. There was no correlation between patient age and the incidence of ADRs. In patients with known history of allergy the incidence of ADRs was increased by a factor 3-4, which is still lower than the incidence reported after intravenous administration of iodinated non-ionic roentgen CM to patients without known allergy. Good renal tolerance was seen in all patients, irrespective of pre-existing renal impairment. Fast bolus injections of Gd-DTPA were tolerated without added risk. The favorable safety profile is also reflected in the post marketing surveillance reports since Gd-DTPA became available as a commercial drug. (author). 7 refs.; 7 figs.; 7 tabs
[en] Objectives: To investigate whether a dose reduction of Gadobutrol for renal magnetic resonance angiography (MRA) at 7 Tesla (T) is feasible while preserving diagnostic image quality. Methods: Ten healthy volunteers were enrolled for a renal MRA on a 7 T scanner. Fast low angle shot (FLASH) MRA data sets were obtained utilizing three different doses of Gadobutrol (0.1, 0.05 and 0.025 mmol/kg body weight [BW]). Contrast ratios (CR) were measured in the aorta as well as in the intra- and extraparenchymal arteries compared to the psoas muscle. Qualitative analysis regarding the delineation of vessel structures was performed using a four-point-scale. Results: All doses of Gadobutrol allowed for a good delineation of the aorta and renal arteries. For the extra- and intraparenchymal segmental arteries higher values were observed for full and half dose in comparison to quarter dose. No significant difference was observed for full and half dose. A lower CR was observed for quarter compared to half dose (p < 0.05) for the renal arteries. Conclusions: While best results were observed for half and full dose, a dose reduction to 0.025 mmol/kg BW is justifiable, maintaining a diagnostic image quality. This may be of high interest considering patients with renal impairment.
[en] The luminescence properties of some rare earth (Ln) ions adsorbed on Porous Vycor Glass (PVG) are studied. The results are used to characterize this system. Vibronic sidebands in the emission spectrum of Gd3+/PVG show that the Ln ions are bound to the surface of the pores of PVG and that they are coordinated on the other side by water molecules. From the decaytime of Eu3+ on PVG the number of coordinating water molecules is found to be 4 Energy transfer experiments show that the mean distance between two adsorbed Ln ions is about 7A
[en] We present the results of magnetization and magneto-transport measurements on the giant magneto-caloric compound Gd3Ge4. A distinct change is observed in the functional form of electric resistance and magnetization after the sample is cycled through the first order transition regime. A change in microstructure akin to training of microstructure in martensites is thought to be underlying the observed changes in transport and magnetic properties. (author)
[en] Rare-earth orthovanadates, a kind of prototypical host, have received extensive attentions owing to their important applications. Although there has been great progress in the control of morphologies and optimization of properties, the intrinsic reasons for the morphology dependence of their luminescence are still unclear. In this work, we chose GdVO4:Eu3+ as a model compound to study. By varying the surfactant dose involved under mild hydrothermal conditions, several distinct morphologies, such as nanorods, nanowafers, nanoparticles, and snowballs were prepared. Depending on the morphologies and residual surfactant content, surface cationic nonstoichiometry and defects, especially for unstable VO4 groups, were demonstrated to exist in GdVO4:Eu3+ nanocrystals. The first experimental evidence for the relationship between surface defect states and luminescent emission of GdVO4:Eu3+ nanocrystals is presented. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)