Steffen Zahn

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PURPOSE The aim of the study was to objectively characterize the function of rods, cones, and intrinsic photosensitive retinal ganglion cells (ipRGCs) in patients with RPE65 mutations by using two published protocols for chromatic pupillometry, and to correlate the data with the clinical phenotype. METHODS The study group comprised 11 patients with RPE65(More)
BACKGROUND The purpose of the study was to evaluate the effects of cyclosporine (CsA), FK 506 and mycophenolate mofetil (MMF) on graft-infiltrating leukocytes (CD4, CD8, CD11a, CD18) after cardiac transplantation in rats. METHODS Three hundred forty animals were transplanted and randomly divided into 4 groups: CsA, 3 mg/kg/d (n = 74); MMF, 40 mg/kg/d (n =(More)
BACKGROUND The interaction of lymphocyte function-associated antigen-1 (LFA-1)-positive host leukocytes with intercellular adhesion molecule-1 (ICAM-1) on graft endothelium may play a key role in allograft recognition, triggering the development of transplant vasculopathy (TVP). We investigated the correlation between TVP and ICAM-1 expression and(More)
This study determines how the magnitude and pattern of cochlear damage is altered when exposure to noise is interrupted by regularly spaced rest periods. Groups of chinchillas were exposed for six hours per session to an octave band of noise with a center frequency of 0.5 kHz. The rest interval between successive exposures varied from 18 to 162 hours. The(More)
Stereodynamic complexes of copper were found to undergo inversion of a helical chiral element upon oxidation or reduction. The amino acid methionine was derivatized by the attachment of two chromophores to the nitrogen atom. The resultant ligands formed stable complexes with Cu(I) and Cu(II) salts. For a derivative of a given absolute chirality, the(More)
This manuscript describes the design, synthesis, and characterization of a coordination complex that demonstrates reversible interconversion between two redox states that show very different chiroptical properties. Reported here are three chiral N(4)-tetradentate ligands, prepared in enantiopure form by asymmetric synthesis, and their circular dichroic and(More)
We report a method to determine the absolute configuration of alpha-amino acids by exciton coupled circular dichroism (ECCD). Naturally occurring amino acids were successfully derivatized with 2-bromomethylquinoline. Complexation of these conformationally flexible ligands with Cu(II) salts yielded defined propeller-like structures. The direction of the(More)
N,N'-Dipicolyl, bis(stilbylvinylpyridylmethyl), and diquinaldyl methionine derivatives form stable Cu(II) complexes with metal ligation by three nitrogen atoms and the carboxylate. One-electron reduction results in the exchange of carboxylate for sulfide in the complexes. This ligand reorganization is accompanied by inversion of the helical orientation of(More)
[formula: see text] A circular dichroism technique has been applied to the absolute configurational assignment of acyclic alpha-amino acids and beta-amino alcohols with single stereogenic centers via a one-step derivitization procedure requiring microgram quantities of material. Metal ions fix the geometrical relationship of two chromophores, affording CD(More)