TY  - JOUR
A1  - Reiter, Theresa
A1  - Ritter, Oliver
A1  - Prince, Martin R.
A1  - Nordbeck, Peter
A1  - Wanner, Christoph
A1  - Nagel, Eike
A1  - Bauer, Wolfgang R.
T1  - Minimizing Risk of Nephrogenic systemic fibrosis in Cardiovascular Magnetic Resonance
N2  - Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5 % have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice.
KW  - CMR
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75068
ER  - 
TY  - JOUR
A1  - Fassnacht, Martin
A1  - Sbiera, Silviu
A1  - Dexneit, Thomas
A1  - Reichardt, Sybille D.
A1  - Michel, Kai D.
A1  - van den Brandt, Jens
A1  - Schmull, Sebastian
A1  - Kraus, Luitgard
A1  - Beyer, Melanie
A1  - Mlynski, Robert
A1  - Wortmann, Sebastian
A1  - Allolio, Bruno
A1  - Reichardt, Holger M.
T1  - Influence of Short-Term Glucocorticoid Therapy on Regulatory T Cells In Vivo
N2  - Background: Pre- and early clinical studies on patients with autoimmune diseases suggested that induction of regulatory T(Treg) cells may contribute to the immunosuppressive effects of glucocorticoids(GCs). Objective: We readdressed the influence of GC therapy on Treg cells in immunocompetent human subjects and naı¨ve mice. Methods: Mice were treated with increasing doses of intravenous dexamethasone followed by oral taper, and Treg cells in spleen and blood were analyzed by FACS. Sixteen patients with sudden hearing loss but without an inflammatory disease received high-dose intravenous prednisolone followed by stepwise dose reduction to low oral prednisolone. Peripheral blood Treg cells were analyzed prior and after a 14 day GC therapy based on different markers. Results: Repeated GC administration to mice for three days dose-dependently decreased the absolute numbers of Treg cells in blood (100 mg dexamethasone/kg body weight: 2.861.86104 cells/ml vs. 336116104 in control mice) and spleen (dexamethasone: 2.861.96105/spleen vs. 956226105/spleen in control mice), which slowly recovered after 14 days taper in spleen but not in blood. The relative frequency of FOXP3+ Treg cells amongst the CD4+ T cells also decreased in a dose dependent manner with the effect being more pronounced in blood than in spleen. The suppressive capacity of Treg cells was unaltered by GC treatment in vitro. In immunocompetent humans, GCs induced mild T cell lymphocytosis. However, it did not change the relative frequency of circulating Treg cells in a relevant manner, although there was some variation depending on the definition of the Treg cells (FOXP3+: 4.061.5% vs 3.461.5%*; AITR+: 0.660.4 vs 0.560.3%, CD127low: 4.061.3 vs 5.063.0%* and CTLA4+: 13.8611.5 vs 15.6612.5%; * p,0.05). Conclusion: Short-term GC therapy does not induce the hitherto supposed increase in circulating Treg cell frequency, neither in immunocompetent humans nor in mice. Thus, it is questionable that the clinical efficacy of GCs is achieved by modulating Treg cell numbers.
KW  - Medizin
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-74749
ER  - 
TY  - JOUR
A1  - Bauer, Wolfgang R.
A1  - Nadler, Walter
T1  - Thermodynamics of Competitive Molecular Channel Transport: Application to Artificial Nuclear Pores
N2  - In an analytical model channel transport is analyzed as a function of key parameters, determining efficiency and selectivity of particle transport in a competitive molecular environment. These key parameters are the concentration of particles, solvent-channel exchange dynamics, as well as particle-in-channel- and interparticle interaction. These parameters are explicitly related to translocation dynamics and channel occupation probability. Slowing down the exchange dynamics at the channel ends, or elevating the particle concentration reduces the in-channel binding strength necessary to maintain maximum transport. Optimized in-channel interaction may even shift from binding to repulsion. A simple equation gives the interrelation of access dynamics and concentration at this transition point. The model is readily transferred to competitive transport of different species, each of them having their individual in-channel affinity. Combinations of channel affinities are determined which differentially favor selectivity of certain species on the cost of others. Selectivity for a species increases if its in-channel binding enhances the species’ translocation probablity when compared to that of the other species. Selectivity increases particularly for a wide binding site, long channels, and fast access dynamics. Recent experiments on competitive transport of in-channel binding and inert molecules through artificial nuclear pores serve as a paradigm for our model. It explains qualitatively and quantitatively how binding molecules are favored for transport at the cost of the transport of inert molecules.
KW  - Thermodynamik
KW  - Transport
KW  - Molekül
KW  - Molecular Channel Transport
KW  - Artificial Nuclear Pores
KW  - Thermodynamics
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68484
ER  -