TY - JOUR A1 - Schiller, E. A1 - Seifert, S. A1 - Tisato, F. A1 - Refosco, F. A1 - Kraus, Werner A1 - Spies, H. A1 - Pietzsch, H.-J. T1 - Mixed-Ligand Rhenium-188 Complexes with Tetradentate/Monodentate NS3/P ('4 + 1') Coordination: Relation of Structure with Antioxidation Stability N2 - Development of new radiopharmaceuticals based on rhenium-188 depends on finding appropriate ligands able to give complexes with high in vivo stability. Rhenium(III) mixed-ligand complexes with tetradentate/monodentate ('4 + 1') coordination of the general formula [Re(NS3)(PRR'R' ')] (NS3 = tris(2-mercaptoethyl)amine and derivatives thereof, PRR'R' ' = phosphorus(III) ligands) appear to be among the promising tools to achieve this goal. According to this approach, we synthesized and characterized a series of rhenium model complexes. In vitro stabilities of the corresponding rhenium-188 complexes were determined by incubating 2-3 MBq or alternatively 37 MBq of the complexes in phosphate buffer, human plasma, and rat plasma, respectively, at 22° C or 37° C, followed by checking the amount of 188ReO4- formed after 1 h, 24, and 48 h by thin-layer chromatography. The rate of perrhenate formation varied over a wide range, depending primarily on the nature of the phosphorus(III) ligand. Physicochemical parameters of the corresponding nonradioactive rhenium complexes were analyzed in detail to find out the factors influencing their different stability and furthermore to design new substitution-inert '4 + 1' complexes. Tolman's cone angle of phosphorus(III) ligands and the lipophilic character of the inner coordination sphere were found to be crucial factors to build up stable rhenium '4 + 1' complexes. Additional information useful to describe electronic and steric properties of these compounds were selected from electronic spectra (wavelength of the ReS charge-transfer band), cyclovoltammetric measurements (E° of the ReIII/ReIV couple), and NMR investigations (31P chemical shift of coordinated P(III) ligands). PY - 2005 UR - http://pubs.acs.org/cgi-bin/abstract.cgi/bcches/2005/16/i03/abs/bc049745a.html SN - 1043-1802 SN - 1520-4812 VL - 16 IS - 3 SP - 634 EP - 643 CY - Washington, DC AN - OPUS4-7547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grote, M. A1 - Noll, S. A1 - Noll, B. A1 - Johannsen, B. A1 - Kraus, Werner T1 - Syntheses of novel modified acyclic purine and pyrimidine nucleosides as potential substrates of herpes simplex virus type-1 thymidine kinase for monitoring gene expression N2 - Suicide gene therapy with the herpes simplex virus type-1 thymidine kinase gene (HSV-1 tk) is considered to be a promising approach to the treatment of cancer. Making use of the lower specificity of the viral enzyme compared to human thymidine kinase, the therapy involves the administration of antiviral agents (e.g., ganciclovir) as prodrugs to induce enzymatic cell death in those cells that express the transferred gene. 18F-labelled derivatives have been described for monitoring location, duration, and magnitude of the viral kinase enzyme activity by positron emission tomography (PET). Since an optimal radiotracer has not been developed, novel substances were synthesized for monitoring gene expression. A group of 13 nucleoside analogues were synthesized, among them N1-methyl-9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (5) and N1-methyl-9-[(4-hydroxy)-3-hydroxymethylbutyl]guanine (7) as methyl analogues of ganciclovir and penciclovir and their related fluoro compounds (6, 8). Further novel derivatives include N6-methyl-9-[(1,3-dihydroxy-2-propoxy)methyl]-, N6-methyl-9-[(4-hydroxy)-3-hydroxymethylbutyl]adenine (9, 10), as well as the uracil derivatives 5-hydroxy-1-[(1,3-dihydroxy-2-propoxy)methyl]uracil (11), 6-methyl-1-[(1,3-dihydroxy-2-propoxy)-methyl]uracil (12), and its 3-fluoro-derivative (13). KW - Fluorinated nucleoside analogues KW - Gene therapy KW - PET KW - Thymidine kinase PY - 2004 DO - https://doi.org/10.1139/v04-005 SN - 0008-4042 SN - 1480-3291 VL - 82 SP - 513 EP - 523 PB - National Research Council of Canada CY - Ottawa, Ont. AN - OPUS4-3490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Walther, M. A1 - Jung, C. M. A1 - Bergmann, R. A1 - Pietzsch, J. A1 - Rode, K. A1 - Fahmy, K. A1 - Mirtschink, P. A1 - Stehr, S. A1 - Heintz, A. A1 - Wunderlich, G. A1 - Kraus, Werner A1 - Pietzsch, H.-J. A1 - Kropp, J. A1 - Deussen, A. A1 - Spies, H. T1 - Synthesis and Biological Evaluation of a New Type of 99mTechnetium-Labeled Fatty Acid for Myocardial Metabolism Imaging PY - 2007 SN - 1043-1802 SN - 1520-4812 VL - 18 SP - 216 EP - 230 CY - Washington, DC AN - OPUS4-14514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drews, A. A1 - Pietzsch, H.-J. A1 - Syhre, R. A1 - Seifert, S. A1 - Varnäs, K. A1 - Hall, H. A1 - Halldin, C. A1 - Kraus, Werner A1 - Karlsson, P. T1 - Synthesis and biological evaluation of technetium(III) mixed-ligand complexes with high affinity for the cerebral 5-HT1A receptor and the alpha-1-adrenergic receptor N2 - Tc(III) and Re(III) complexes [M(NS3)(CNR)] (M = Re, 99mTc, NS3 = 2,2?,2?-nitrilotris(ethanethiol), CNR = functionalized isocyanide bearing a derivative of WAY 100635) have been synthesized and characterized. Re was used as Tc surrogate for chemical characterization and in vitro receptor-binding studies. For two representatives subnanomolar affinities for the 5-HT1A as well as for the alpha1-adrenergic receptor were reached. Biodistribution studies in rats of the 99mTc complexes showed brain uptakes between 0.3 and 0.5% ID/organ (5 min p.i.). In vitro autoradiography of one 99mTc representative in sections of post mortem human brain indicate its accumulation in 5-HT1A receptor-rich brain regions. However, addition of the specific 5-HT1A receptor agonist 8-OH-DPAT as well as the alpha1-adrenoceptor antagonist prazosin could not substantially block this tracer accumulation. A preliminary SPET study in a monkey showed negligible brain uptake. KW - 5-HT1A receptor KW - Alpha 1-adrenergic receptor KW - Technetium-99m KW - Rhenium KW - Autoradiography KW - SPET PY - 2002 DO - https://doi.org/10.1016/S0969-8051(02)00296-2 SN - 0883-2897 VL - 29 IS - 4 SP - 389 EP - 398 PB - Elsevier Science Inc. CY - New York, NY AN - OPUS4-1553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moldovan, R.-P. A1 - Wenzel, B. A1 - Teodoro, R. A1 - Neumann, W. A1 - Dukic-Stefanovic, S. A1 - Kraus, Werner A1 - Rong, P. A1 - Deuther-Conrad, W. A1 - Hey-Hawkins, E. A1 - Krügel, U. A1 - Brust, P. T1 - Studies towards the development of a PET radiotracer for imaging of the P2Y1 receptors in the brain: synthesis, 18F-labeling and preliminary biological evaluation N2 - Purine nucleotides such as ATP and ADP are important extracellular signaling molecules in almost all tissues activating various subtypes of purinoreceptors. In the brain, the P2Y1 receptor (P2Y1R) subtype mediates trophic functions like differentiation and proliferation, and modulates fast synaptic transmission, both suggested to be affected in diseases of the central nervous system. Research on P2Y1R is limited because suitable brain-penetrating P2Y1R-selective tracers are not yet available. Here, we describe the first efforts to develop an 18F-labeled PET tracer based on the structure of the highly affine and selective, non-nucleotidic P2Y1R allosteric modulator 1-(2-[2-(tert-butyl)phenoxy]pyridin-3-yl)-3- [4-(trifluoromethoxy)phenyl]urea (7). A small series of fluorinated compounds was developed by systematic modification of the p-(trifluoromethoxy)phenyl, the urea and the 2-pyridyl subunits of the lead compound 7. Additionally, the p-(trifluoromethoxy)phenyl subunit was substituted by carborane, a boron-rich cluster with potential applicability in boron neutron capture therapy (BNCT). By functional assays, the new fluorinated derivative 1-{2-[2-(tert-butyl)phenoxy]pyridin-3-yl}-3-[4-(2-fluoroethyl) phenyl]urea (18) was identified with a high P2Y1R antagonistic potency (IC50 ¼10 nM). Compound [18F] 18 was radiosynthesized by using tetra-n-butyl ammonium [18F]fluoride with high radiochemical purity, radiochemical yield and molar activities. Investigation of brain homogenates using hydrophilic interaction chromatography (HILIC) revealed [18F]fluoride as major radiometabolite. Although [18F]18 showed fast in vivo metabolization, the high potency and unique allosteric binding mode makes this class of compounds interesting for further optimizations and investigation of the theranostic potential as PET tracer and BNCT agent. KW - Purine P2Y1 receptors KW - Positron emission tomography KW - Brain PET tracers KW - Radiometabolites KW - Micellar chromatography KW - Hydrophilic interaction chromatography PY - 2019 DO - https://doi.org/10.1016/j.ejmech.2019.01.006 SN - 0223-5234 VL - 165 SP - 142 EP - 159 PB - Elsevier CY - Amsterdam AN - OPUS4-47253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, Werner A1 - Emmerling, Franziska A1 - Noll, B. A1 - Noll, S. A1 - Pietzsch, H.-J. T1 - (4-Methoxybenzenethiolato-kS)oxido[2,2'-(propylimino)bis-(ethanethiolato)-k3S,N,S']rhenium(V) N2 - The central Re atom of the mononuclear title complex, [Re(C8H18NS2)(C6H4OS)O], is five-coordinate (ReNOS3) with a square-pyramidal geometry comprising a tridentate 2,2'-(propylimino)diethanethiolate ligand, a 4-methoxybenzenethiolate ligand and a doubly-bonded O atom. PY - 2007 DO - https://doi.org/10.1107/S1600536807056814 SN - 1600-5368 VL - 63 IS - 12 SP - m3018 PB - Munksgaard CY - Copenhagen AN - OPUS4-16196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Kraus, Werner A1 - Noll, B. A1 - Noll, S. A1 - Pietzsch, H.-J. T1 - Two mononuclear Tc complexes: [2,2'-(3-phenylpropylimino)- and [2,2'-(propylimino)bis(ethanethiolato)](4-methoxybenzenethiolato)-oxidotechnate(V) PY - 2007 DO - https://doi.org/10.1107/S0108270107052870 SN - 0108-2701 SN - 1600-5759 VL - 63 IS - 12 SP - m579 EP - m582 PB - Blackwell Publ. CY - Oxford AN - OPUS4-16283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mirtschink, P. A1 - Stehr, S.N. A1 - Pietzsch, H.J. A1 - Bergmann, R. A1 - Pietzsch, J. A1 - Wunderlich, G. A1 - Heintz, A.C. A1 - Kropp, J. A1 - Spies, H. A1 - Kraus, Werner A1 - Deussen, A. A1 - Walther, M. T1 - Modified "4+1" Mixed Ligand Technetium-Labeled Fatty Acids for Myocardial Imaging: Evaluation of Myocardial Uptake and Biodistribution N2 - Our group previously synthesized 99mTc-labeled fatty acids suitable for myocardial metabolism and flow imaging. In this set of experiments, 29 new analogues were synthesized according to the “4 + 1” mixed ligand approach with some specific differences. Conventional “4 + 1” 99mTc-fatty acids are built in the sequence: Tc-chelate, alkyl chain, and carboxylic group. We developed compounds following a new design with the sequence: carboxylic group, alkyl chain, Tc-chelate, and lipophilic tail. Therefore, the 99mTc-chelate was transferred to a more central position of the compound, aiming toward an improved myocardial profile and an accelerated liver clearance. In this context, several functional groups incorporated in the lipophilic tail section were tested to evaluate their influence on the compound's character. In addition to biodistribution studies in vivo, the myocardial first-pass extraction of the compounds was tested in an isolated Langendorff rat heart model. A satisfactory myocardial uptake of up to 20% of the injected dose (% ID) in the perfused heart and a fast liver clearance in vivo with only 0.29% ID/g at 60 min postinjection demonstrate that the induced molecular modifications affect the kinetics of 99mTc-radiolabeled fatty acid compounds favorably. From the data set, rules for estimating the biodistribution of fatty acids tracers are deduced. PY - 2008 DO - https://doi.org/10.1021/bc700164c SN - 1043-1802 SN - 1520-4812 VL - 19 IS - 1 SP - 97 EP - 108 CY - Washington, DC AN - OPUS4-16499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -