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Surci N, Marchegiani G, Andrianello S, Pollini T, Mühlbacher J, Jomrich G, Richwien P, Tamandl D, Schindl M, Bassi C, Salvia R, Sahora K. The faith of non-surveilled pancreatic cysts: a bicentric retrospective study. Eur J Surg Oncol 2021; 48:89-94. [PMID: 34148825 DOI: 10.1016/j.ejso.2021.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/06/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Incidental discovery of pancreatic cystic neoplasms (PCLs) is a common and steadily increasing occurrence. The aim of this study was to investigate a cohort of patients presenting with incidentally detected PCLs which were not included in a surveillance protocol, and to compare their risk of malignant evolution with that of systematically surveilled lesions. MATERIALS AND METHODS A population of PCLs which did not receive surveillance over a period >10 years (population A) was selected at the Medical University of Vienna. A group of "low risk" branch duct intraductal papillary mucinous neoplasm ≤15 mm in size upon diagnosis undergoing a regular follow-up of at least 5 years at the University of Verona was selected as control (population B). The incidence of pancreatic cancer (PC), cumulative risk of PC and disease-specific survival were compared. RESULTS Overall, 376 patients with non-surveilled PCLs were included in study group A and compared to 299 patients in group B. This comparison resulted in similar incidence rates of PC (1.6% vs 1.7%, p = 0.938), a strong similarity in terms of disease-specific mortality rates (1.3% vs 0.3%, p = 0.171) and the 5- and 10-year cumulative risk of PC (≅ 1% and 2%, p = 0.589) and DSS (≅ 100% and 98%, p = 0.050). CONCLUSION The "price to pay" for a negligence-based policy in the population of non-surveilled PCLs was reasonable, and the incidence of PC was comparable to that reported for a population of low-risk cysts enrolled to a standardized surveillance protocol.
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Affiliation(s)
- N Surci
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria; Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy
| | - G Marchegiani
- Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy.
| | - S Andrianello
- Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy
| | - T Pollini
- Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy
| | - J Mühlbacher
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria
| | - G Jomrich
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria
| | - P Richwien
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria
| | - D Tamandl
- Department of Radiology, Medical University of Vienna, General Hospital, Vienna, Austria
| | - M Schindl
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria
| | - C Bassi
- Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy
| | - R Salvia
- Department of General and Pancreatic Surgery, Pancreas Institute, University and Hospital Trust of Verona, "GB Rossi" Hospital, Verona, Italy
| | - K Sahora
- Department of Surgery, Medical University of Vienna, General Hospital, Vienna, Austria
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2
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Schoergenhofer C, Matzneller P, Mühlbacher J, Hell L, Zeitlinger M, Jilma B. PCSK9 decreases during experimental endotoxemia. J Intern Med 2020; 287:333-335. [PMID: 31660669 DOI: 10.1111/joim.13003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 11/30/2022]
Affiliation(s)
- C Schoergenhofer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - P Matzneller
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - J Mühlbacher
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - L Hell
- Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - M Zeitlinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - B Jilma
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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3
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Eskandary F, Jilma B, Mühlbacher J, Wahrmann M, Regele H, Kozakowski N, Firbas C, Panicker S, Parry GC, Gilbert JC, Halloran PF, Böhmig GA. Anti-C1s monoclonal antibody BIVV009 in late antibody-mediated kidney allograft rejection-results from a first-in-patient phase 1 trial. Am J Transplant 2018; 18:916-926. [PMID: 28980446 DOI: 10.1111/ajt.14528] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 09/03/2017] [Accepted: 09/24/2017] [Indexed: 01/25/2023]
Abstract
The classical pathway (CP) of complement may contribute to the pathogenesis of antibody-mediated rejection (ABMR). Selective CP blockade may be a promising strategy to counteract rejection. The objective of this first-in-patient phase 1b trial was to evaluate the safety/tolerability and CP-blocking potential of 4 weekly doses (60 mg/kg) of the anti-C1s antibody BIVV009 in complement-mediated disorders. Here we describe the results in a cohort of 10 stable kidney transplant recipients (median of 4.3 years posttransplantation) with late active ABMR and features of CP activation, such as capillary C4d or complement-fixing donor-specific antibodies (DSA). During 7 weeks follow-up, no severe adverse events were reported, and BIVV009 profoundly inhibited overall and DSA-triggered CP activation in serum. Five of 8 C4d-positive recipients turned C4d-negative in 5-week follow-up biopsies, while another 2 recipients showed a substantial decrease in C4d scores. There was, however, no change in microcirculation inflammation, gene expression patterns, DSA levels, or kidney function. In conclusion, we demonstrate that BIVV009 effectively blocks alloantibody-triggered CP activation, even though short-course treatment had no effect on indices of activity in late ABMR. This initial trial provides a valuable basis for future studies designed to clarify the therapeutic value of CP blockade in transplantation. ClinicalTrials.gov NCT#02502903.
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Affiliation(s)
- F Eskandary
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - B Jilma
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - J Mühlbacher
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - M Wahrmann
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - H Regele
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - N Kozakowski
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - C Firbas
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - S Panicker
- Bioverativ Therapeutics, Inc, South San Francisco, CA, USA
| | - G C Parry
- Bioverativ Therapeutics, Inc, South San Francisco, CA, USA
| | - J C Gilbert
- True North Therapeutics, Inc, South San Francisco, CA, USA
| | - P F Halloran
- Alberta Transplant Applied Genomics Centre, ATAGC, University of Alberta, Edmonton, AB, Canada
| | - G A Böhmig
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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4
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Wahrmann M, Mühlbacher J, Marinova L, Regele H, Huttary N, Eskandary F, Cohen G, Fischer GF, Parry GC, Gilbert JC, Panicker S, Böhmig GA. Effect of the Anti-C1s Humanized Antibody TNT009 and Its Parental Mouse Variant TNT003 on HLA Antibody-Induced Complement Activation-A Preclinical In Vitro Study. Am J Transplant 2017; 17:2300-2311. [PMID: 28251805 PMCID: PMC5600102 DOI: 10.1111/ajt.14256] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 01/31/2017] [Accepted: 02/17/2017] [Indexed: 01/25/2023]
Abstract
The classic pathway (CP) of complement is believed to significantly contribute to alloantibody-mediated transplant injury, and targeted complement inhibition is currently considered to be a promising approach for preventing rejection. Here, we investigated the mode of action and efficacy of the humanized anti-C1s monoclonal antibody TNT009 and its parental mouse variant, TNT003, in preclinical in vitro models of HLA antibody-triggered CP activation. In flow cytometric assays, we measured the attachment of C1 subcomponents and C4/C3 split products (C4b/d, C3b/d) to HLA antigen-coated flow beads or HLA-mismatched aortic endothelial cells and splenic lymphocytes. Anti-C1s antibodies profoundly inhibited C3 activation at concentrations >20 μg/mL, in both solid phase and cellular assays. While C4 activation was also prevented, this was not the case for C1 subcomponent attachment. Analysis of serum samples obtained from 68 sensitized transplant candidates revealed that the potency of inhibition was related to the extent of baseline CP activation. This study demonstrates that anti-C1s antibodies TNT009 and TNT003 are highly effective in blocking HLA antibody-triggered complement activation downstream of C1. Our results provide the foundation for clinical studies designed to investigate the potential of TNT009 in the treatment or prevention of complement-mediated tissue injury in sensitized transplant recipients.
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Affiliation(s)
- M. Wahrmann
- Division of Nephrology and DialysisDepartment of Medicine IIIMedical University ViennaViennaAustria
| | - J. Mühlbacher
- Department of SurgeryMedical University ViennaViennaAustria
| | - L. Marinova
- Division of Nephrology and DialysisDepartment of Medicine IIIMedical University ViennaViennaAustria
| | - H. Regele
- Clinical Institute of PathologyMedical University ViennaViennaAustria
| | - N. Huttary
- Clinical Institute of PathologyMedical University ViennaViennaAustria
| | - F. Eskandary
- Division of Nephrology and DialysisDepartment of Medicine IIIMedical University ViennaViennaAustria
| | - G. Cohen
- Division of Nephrology and DialysisDepartment of Medicine IIIMedical University ViennaViennaAustria
| | - G. F. Fischer
- Department of Blood Group Serology and Transfusion MedicineMedical University ViennaViennaAustria
| | - G. C. Parry
- True North Therapeutics, Inc.South San FranciscoCA
| | | | - S. Panicker
- True North Therapeutics, Inc.South San FranciscoCA
| | - G. A. Böhmig
- Division of Nephrology and DialysisDepartment of Medicine IIIMedical University ViennaViennaAustria
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Ertl P, Jelfs S, Mühlbacher J, Schuffenhauer A, Selzer P. Quest for the rings. In silico exploration of ring universe to identify novel bioactive heteroaromatic scaffolds. J Med Chem 2006; 49:4568-73. [PMID: 16854061 DOI: 10.1021/jm060217p] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioactive molecules only contain a relatively limited number of unique ring types. To identify those ring properties and structural characteristics that are necessary for biological activity, a large virtual library of nearly 600 000 heteroaromatic scaffolds was created and characterized by calculated properties, including structural features, bioavailability descriptors, and quantum chemical parameters. A self-organizing neural network was used to cluster these scaffolds and to identify properties that best characterize bioactive ring systems. The analysis shows that bioactivity is very sparsely distributed within the scaffold property and structural space, forming only several relatively small, well-defined "bioactivity islands". Various possible applications of a large database of rings with calculated properties and bioactivity scores in the drug design and discovery process are discussed, including virtual screening, support for the design of combinatorial libraries, bioisosteric design, and scaffold hopping.
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Affiliation(s)
- Peter Ertl
- Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland.
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7
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Bringmann G, Lang G, Gulder TA, Tsuruta H, Mühlbacher J, Maksimenka K, Steffens S, Schaumann K, Stöhr R, Wiese J, Imhoff JF, Perović-Ottstadt S, Boreiko O, Müller WE. The first sorbicillinoid alkaloids, the antileukemic sorbicillactones A and B, from a sponge-derived Penicillium chrysogenum strain. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.05.026] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bringmann G, Lang G, Mühlbacher J, Schaumann K, Steffens S, Rytik PG, Hentschel U, Morschhäuser J, Müller WEG. Sorbicillactone A: a structurally unprecedented bioactive novel-type alkaloid from a sponge-derived fungus. Prog Mol Subcell Biol 2005; 37:231-53. [PMID: 15825646 DOI: 10.1007/978-3-642-55519-0_9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
This chapter deals with the discovery of sorbicillactone A, as an illustrative example of the fruitful cooperation within BIOTECmarin--its isolation and chemical characterization, and its biological activities. Sorbicillactone A was isolated from a strain of Penicillium chrysogenum cultured from a sample of the Mediterranean sponge Ircinia fasciculata; it possesses a unique bicyclic lactone structure, seemingly derived from sorbicillin. Among the numerous known sorbicillin-derived structures, it is the first found to contain nitrogen and thus the first representative of a novel type of 'sorbicillin alkaloids', apparently originating from a likewise remarkable biosynthesis. Furthermore, the compound exhibits promising activities in several mammalian and viral test systems, in particular a highly selective cytostatic activity against murine leukemic lymphoblasts (L5178y) and the ability to protect human T cells against the cytopathic effects of HIV-1. These properties qualify sorbicillactone A or one of its derivatives for animal and (hopefully) also future therapeutic human trials.
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Affiliation(s)
- G Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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9
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Bracher F, Eisenreich WJ, Mühlbacher J, Dreyer M, Bringmann G. Saludimerines A and B, Novel-Type Dimeric Alkaloids with Stereogenic Centers and Configurationally Semistable Biaryl Axes. J Org Chem 2004; 69:8602-8. [PMID: 15575735 DOI: 10.1021/jo048631p] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first biarylic bis-morphinanedienone alkaloids, saludimerines A (3a) and B (3b), isolated from a tree of Croton flavens (Euphorbiaceae) are described. These naturally occurring dimers of the known alkaloid salutaridine are joined together via a rotationally hindered biaryl axis, giving rise to atropo-diastereomers that are configurationally stable at room temperature but slowly interconvert in methanolic solution within several days. Their structures were established by spectroscopic methods and by partial synthesis, which was achieved by a highly atropo-diastereoselective biomimetic oxidative coupling of the monomeric precursor, salutaridine. Their axial configurations were elucidated by circular dichroism (CD) investigations, which succeeded despite the fact that the two atropo-diastereomers exhibit near-identical CD spectra. This remarkable phenomenon was rationalized by quantum chemical CD calculations. The configurational assignment of saludimerines A (3a) as P-axial and B (3b) as M was corroborated by atropisomer-specific NOE interactions between protons of the one molecular half with nuclei in the other.
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Affiliation(s)
- Franz Bracher
- Department Pharmazie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, D-81377 Münich, Germany.
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10
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Bringmann G, Feineis D, God R, Maksimenka K, Mühlbacher J, Messer K, Münchbach M, Gulden KP, Peters EM, Peters K. Resolution and chiroptical properties of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) and related compounds: quantum chemical CD calculations and X-ray diffraction analysis. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.093] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bringmann G, Mühlbacher J, Reichert M, Dreyer M, Kolz J, Speicher A. Stereochemistry of Isoplagiochin C, A Macrocyclic Bisbibenzyl from Liverworts. J Am Chem Soc 2004; 126:9283-90. [PMID: 15281819 DOI: 10.1021/ja0373162] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclic bisbibenzyls, like isoplagiochins C (1) and D (2), are stereochemically intriguing molecules: Although not equipped with any of the traditional stereogenic elements that render molecules conformationally stable per se, they are sometimes isolated in an optically active form and are thus chiral at room temperature. The paper describes quantum chemical calculations, in particular investigations of the conformational space and molecular dynamics simulations, showing that the helicity is a property of the entire molecule, whose ring strain makes the molecule configurationally stable overall, with (formally) three stereogenic elements (two biaryl axes and one helical stilbene unit). Only one of the biaryl axes (the 'upper' one, joining C-12' and C-14) has a stable configuration, leading to a population of four interconverting diastereomers, yet without racemization at room temperature. On the basis of these conformational and dynamic calculations, the circular dichroism spectrum of isoplagiochin C (1) was calculated, leading to the first assignment of the absolute configuration of a cyclic bisbibenzyl. Accordingly, 1 has the P-configuration at the stereochemically stable biaryl axis and constitutes a mixture of diastereomers with respect to the other biaryl axis and the helical stilbene unit. From the temperature dependence of the racemization rates, an enantiomerization barrier of 101.6 kJ/mol was determined. Likewise, for the first time for cyclic bisbibenzyls, the enantiomeric ratio of this natural product was determined, by chromatography on a chiral phase with CD-coupling. Accordingly, 1 from Plagiochila deflexa is not enantiomerically pure, but occurs in a 85:15 ratio in favor of the enantiomer that has the P-configuration at the stereochemically stable axis.
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Affiliation(s)
- Gerhard Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Ertl P, Mühlbacher J, Rohde B, Selzer P. Web-based cheminformatics and molecular property prediction tools supporting drug design and development at Novartis. SAR QSAR Environ Res 2003; 14:321-328. [PMID: 14758976 DOI: 10.1080/10629360310001673917] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Web-based tools offer many advantages for processing chemical information, most notably ease of use and high interactivity. Therefore more and more pharmaceutical companies are using web technology to deliver sophisticated molecular processing tools directly to the desks of their chemists, to assist them in the process of designing and developing new drugs. In this paper, the web-based cheminformatics system developed at Novartis and currently used by more than thousand users is described. The system allows various molecular modeling and molecular processing tasks, including the calculation of molecular and substituent properties, property-based virtual screening, visualization of molecules, bioisosteric design, diversity analysis, and support of combinatorial chemistry. The methodology to calculate various molecular properties relevant to drug design is described, including the prediction of intestinal absorption, blood-brain barrier penetration, efflux, and water solubility. Information about the web technology used is also provided.
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Affiliation(s)
- P Ertl
- Novartis Institute for Biomedical Research, WKL-125.14.20, CH-4002 Basel, Switzerland.
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Bringmann G, Mühlbacher J, Messer K, Dreyer M, Ebel R, Nugroho BW, Wray V, Proksch P. Cyclorocaglamide, the first bridged cyclopentatetrahydrobenzofuran, and a related "open chain" rocaglamide derivative from Aglaia oligophylla. J Nat Prod 2003; 66:80-5. [PMID: 12542350 DOI: 10.1021/np020291k] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two rocaglamide-related natural products, the previously known compound 6-demethoxy-10-hydroxy-11-methoxy-6,7-methylendioxyrocaglamide (3), and cyclorocaglamide (4), its 8b,10-anhydro analogue, have been isolated from the tropical plant Aglaia oligophylla. Compound 4 is the first bridged cyclopentatetrahydrobenzofuran natural product, and it exhibited a CD spectrum virtually opposite that of all the other rocaglamide natural products known so far, but it still has the same absolute configuration at all stereogenic centers of the basic molecular framework. This was shown unequivocally by quantum chemical CD calculations (here based on molecular dynamics-weighted force field structures) and was finally confirmed experimentally, by a "biomimetic-type" cyclization of 3 to give 4, with the expected "inversion" of the CD spectrum. The opposite chiroptical properties of 3 and 4, despite their homochiral character, underline the necessity of handling chiroptical data with the greatest care, e.g., by simulating them by quantum chemical CD calculations. Compound 3 exhibited an LC(50) of 2.5 ppm when evaluated against neonate larvae of Spodoptera littoralis, while 4 was inactive in this assay up to 100 ppm.
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Affiliation(s)
- Gerhard Bringmann
- Institut für Organische Chemie der Universität, Am Hubland, D-97074 Würzburg, Germany.
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Bringmann G, Menche D, Mühlbacher J, Reichert M, Saito N, Pfeiffer SS, Lipshutz BH. On the verge of axial chirality: atroposelective synthesis of the AB-biaryl fragment of vancomycin. Org Lett 2002; 4:2833-6. [PMID: 12182567 DOI: 10.1021/ol026182e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[structure: see text] Using the "lactone concept", differently substituted AB-biaryl fragments (P)-2 (R = Me, t-Bu) of vancomycin have been synthesized atroposelectively. Their otherwise configurational instability was remedied by inclusion of two chlorine atoms in the B ring to give (M)-29. Starting from a still configurationally unstable lactone-bridged precursor, we obtained this biaryl with high atroposelectivity (dr 94:6) by ring cleavage with dynamic kinetic diastereomeric resolution.
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Affiliation(s)
- Gerhard Bringmann
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Bringmann G, Menche D, Kraus J, Mühlbacher J, Peters K, Peters EM, Brun R, Bezabih M, Abegaz BM. Atropo-enantioselective total synthesis of knipholone and related antiplasmodial phenylanthraquinones. J Org Chem 2002; 67:5595-610. [PMID: 12153257 DOI: 10.1021/jo020189s] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The "lactone concept" has been efficiently employed for the first atropo-enantioselective synthesis of knipholone and related natural phenylanthraquinones. Besides the regio- and stereoselective construction of the biaryl axis, another important step was the "synthetically late" introduction of the C-acetyl group, either by a Friedel-Crafts type acetylation or by an ortho-selective Fries rearrangement first tested on simplified model systems and subsequently applied to the highly atroposelective preparation of the natural products and of simplified analogs thereof for biotesting. The synthetic availability of these natural biaryls, their precursors, and their unnatural analogs permitted a broader investigation of the antiplasmodial activities of these interesting biaryls.
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Affiliation(s)
- Gerhard Bringmann
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Abegaz BM, Bezabih M, Msuta T, Brun R, Menche D, Mühlbacher J, Bringmann G. Gaboroquinones A and B and 4'-O-demethylknipholone-4'-O-beta-D-glucopyranoside, phenylanthraquinones from the roots of Bulbine frutescens. J Nat Prod 2002; 65:1117-1121. [PMID: 12193014 DOI: 10.1021/np0201218] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The novel phenylanthraquinones 4'-O-demethylknipholone-4'-O-beta-D-glucopyranoside (2) and gaboroquinones A (3) and B (4) were isolated from the African medicinal plant Bulbine frutescens. Biaryl 2 represents the first phenylanthraquinone glucoside, while 3 and 4 are the first side-chain-hydroxylated phenylanthraquinones. Their constitutions were determined by spectroscopic analysis, in particular by HMBC, HMQC, and ROESY NMR investigations, and by chemical transformations. The axial configurations were elucidated chemically, by deglucosylation of 2 and by side-chain deoxygenation of 3 and 4 to give the known phenylanthraquinones 4'-O-demethylknipholone (5), isoknipholone (6), and knipholone (1), respectively, and chiroptically, by CD investigations. Compounds 2, 3, and 4 showed moderate to good antiplasmodial and antitrypanosomal activities in vitro.
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Affiliation(s)
- Berhanu M Abegaz
- Department of Chemistry, University of Botswana, Private Bag 0022, Gaborone, Botswana
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Meyring M, Mühlbacher J, Messer K, Kastner-Pustet N, Bringmann G, Mannschreck A, Blaschke G. In vitro biotransformation of (R)- and (S)-thalidomide: application of circular dichroism spectroscopy to the stereochemical characterization of the hydroxylated metabolites. Anal Chem 2002; 74:3726-35. [PMID: 12175160 DOI: 10.1021/ac0203138] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Circular dichroism (CD) spectroscopy was successfully used for the stereochemical characterization of the hydroxylated metabolites formed during the in vitro biotransformation of (R)- and (S)-thalidomide. Incubation extracts of the individual enantiomers were analyzed by HPLC on an achiral stationary phase combined with CD detection. The CD data of the almost enantiopure eluates of the metabolites were compared with the CD spectra quantum chemically calculated for the respective structures. The results allowed us a reliable determination of the absolute stereostructure for all of the metabolites. The chiral center of thalidomide is unaffected by the stereoselective biotransformation process. (3'R,5'R)-trans-5'-hydroxythalidomide is the main metabolite of (R)-thalidomide, which epimerizes spontaneously to give the more stable (3'S,5'R)-cis isomer. On the contrary, (S)-thalidomide is preferentially metabolized by hydroxylation in the phthalimide moiety, resulting in the formation of (S)-5-hydroxythalidomide.
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Affiliation(s)
- Michael Meyring
- Institute of Pharmaceutical Chemistry, University of Münster, Germany
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Bringmann G, Messer K, Wolf K, Mühlbacher J, Grüne M, Brun R, Louis AM. Dioncophylline E from Dioncophyllum thollonii, the first 7,3'-coupled dioncophyllaceous naphthylisoquinoline alkaloid. Phytochemistry 2002; 60:389-397. [PMID: 12031431 DOI: 10.1016/s0031-9422(02)00109-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The isolation and structural elucidation of dioncophylline E, a novel naphthylisoquinoline alkaloid from the rare West African liana Dioncophyllum thollonii, is described. The alkaloid displays an unusual 7,3'-linkage between the naphthalene and the isoquinoline portions. Due to the resulting medium degree of steric hindrance exerted by the ortho-substituents next to the biaryl axis, the compound undergoes slow rotation about the axis at room temperature and thus is the first such alkaloid that occurs as a mixture of two configurationally semi-stable atropo-diastereomers. Dioncophylline E exhibits good antimalarial activity against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum while its antitrypanosomal activity against Trypanosoma cruzi is weak and that against T. brucei rhodesiense is moderate. Furthermore, four additional naphthylisoquinoline alkaloids previously known from the related plant species Triphyophyllum peltatum, have been identified in D. thollonii.
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Affiliation(s)
- Gerhard Bringmann
- Institut für Organische Chemie der Universität, Am Hubland, D-97074 Würzburg, Germany.
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Feling R, Polborn K, Steglich W, Mühlbacher J, Bringmann G. Corrigendum to “The absolute configuration of the mushroom metabolites involutin and chamonixin”[Tetrahedron 57 (2001) 7857–7863]. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)01077-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Feling R, Polborn K, Steglich W, Mühlbacher J, Bringmann G. The absolute configuration of the mushroom metabolites involutin and chamonixin. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00761-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bringmann G, Mühlbacher J, Repges C, Fleischhauer J. MD-based CD calculations for the assignment of the absolute axial configuration of the naphthylisoquinoline alkaloid dioncophylline A. J Comput Chem 2001. [DOI: 10.1002/jcc.1084] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Dreyer M, Nugroho BW, Bohnenstengel FI, Ebel R, Wray V, Witte L, Bringmann G, Mühlbacher J, Herold M, Hung PD, Kiet LC, Proksch P. New insecticidal rocaglamide derivatives and related compounds from Aglaia oligophylla. J Nat Prod 2001; 64:415-420. [PMID: 11325219 DOI: 10.1021/np000123x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Organic-soluble extracts of the twigs of Aglaia oligophylla collected in Vietnam yielded four insecticidal cyclopentatetrahydrobenzofurans of the rocaglamide type including one new natural product (compound 4). Moreover, two cyclopentatetrahydrobenzopyran derivatives, belonging to the aglain and aglaforbesin types, respectively, were also isolated. The aglaforbesin derivative 6 proved likewise to be a new natural product. All isolated rocaglamide, aglain, and aglaforbesin derivatives have a characteristic methylenedioxy substituent linked to C-6 and C-7 or to C-7 and C-8, respectively. Structure elucidation of the new natural products and the determination of the absolute configuration of compound 1 by calculation of its CD spectrum with molecular dynamics simulation are described. All isolated rocaglamide derivatives exhibited strong insecticidal activity toward neonate larvae of the polyphageous pest insect Spodoptera littoralis when incorporated into an artificial diet, with LC(50) values varying between 2.15 and 6.52 ppm.
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Affiliation(s)
- M Dreyer
- Institut für Pharmazeutische Biologie, Heinrich Heine Universität, Düsseldorf, Universitätsstrasse 1, Gebäude 26.23, D-40225 Düsseldorf, Germany
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Bringmann G, Tasler S, Endress H, Mühlbacher J. En route to the first stereoselective synthesis of axially chiral biscarbazole alkaloids. Chem Commun (Camb) 2001. [DOI: 10.1039/b101241j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Bringmann G, Schlauer J, Rischer H, Wohlfarth M, Mühlbacher J, Buske A, Porzel A, Schmidt J, Adam G. Revised Structure of Antidesmone, an Unusual Alkaloid from Tropical Antidesma Plants (Euphorbiaceae). Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00289-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bringmann G, Günther C, Mühlbacher J, Lalith MD, Gunathilake P, Wickramasinghe A. Tropane alkaloids from Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae). Phytochemistry 2000; 53:409-416. [PMID: 10703067 DOI: 10.1016/s0031-9422(99)00561-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Six tropane alkaloids were isolated from the Sri Lankan endemic plant Erythroxylum zeylanicum O.E. Schulz (Erythroxylaceae) and structurally elucidated by NMR and MS measurements. Three of them, erythrozeylanines A [1R,3R,5S,6R-6-acetoxy-3-(3',4',5'-trimethoxybenzoyloxy)tropane], B [cis-3 beta-(cinnamoyloxy)tropane], and C [cis-6 beta-acetoxy-3 alpha-(cinnamoyloxy)tropane] are new, whereas the others have already been found in other Erythroxylum species. For the first time, the absolute configuration of a tropane alkaloid (erythrozeylanine A) has been determined by quantum chemical CD calculations.
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Affiliation(s)
- G Bringmann
- Institut für Organische Chemie der Universität, Würzburg, Germany.
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Buske A, Busemann S, Mühlbacher J, Schmidt J, Porzel A, Bringmann G, Adam G. Antidesmone, a novel type isoquinoline alkaloid from Antidesma membranaceum (Euphorbiaceae). Tetrahedron 1999. [DOI: 10.1016/s0040-4020(98)01107-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kment G, Georgopoulos A, Ridl W, Mühlbacher J. Amoxicillin concentrations in nasal secretions of patients with acute uncomplicated sinusitis and in paranasal sinus mucosa of patients with chronic sinusitis. Eur Arch Otorhinolaryngol 1995; 252:236-8. [PMID: 7546679 DOI: 10.1007/bf00179917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this prospective randomized clinical study a total of 59 patients of both sexes (above 18 years of age) were enrolled. Thirty patients with acute sinusitis were randomly allocated to two treatment groups, one group receiving 1000 mg amoxicillin every 12 h for 10 days and the other group receiving 500 mg amoxicillin every 8 h for 10 days. The median concentration of amoxicillin in nasal secretions was 2.34 micrograms/ml in the 12-h administration group and 1.95 micrograms/ml in the 8-h administration group. Median bioavailability of antibiotic at 8-24 h did not show any statistical differences between the two treatment schemes [probability (Z) = 0.2]. Twenty-nine patients with chronic sinusitis were then randomly allocated to three groups, with patients receiving 1000 mg amoxicillin at 12, 8 or 6 h before nasal and/or sinus surgery was carried out. The mean amoxicillin concentrations in mucosal tissues removed intraoperatively ranged from 0.69 to 0.99 microgram/g samples. Statistical evaluation by analysis of variance did not show any statistically significant differences among the three treatment groups [probability (F) = 0.1705]. In all cases of acute and chronic sinusitis, amoxicillin concentrations exceeded minimum inhibitory concentration values for pathogens common in sinusitis. Our results indicate that 1000 mg amoxicillin administered twice daily produces tissue concentrations high enough to be clinically effective in patients with either acute or chronic sinusitis.
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Affiliation(s)
- G Kment
- ENT Department, Faculty of Medicine, University of Vienna, Austria
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Affiliation(s)
- M Nada
- Department of Dermatology, Cairo University, Egypt
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Guggenbichler JP, Georgopoulos A, Scharrer P, Kobilansky C, Mühlbacher J, Georgopoulos M, Dierich MP. Antimicrobial activity of josamycin against erythromycin-resistant staphylococci as compared to roxythromycin and clarithromycin. Infection 1993; 21:259-61. [PMID: 8225634 DOI: 10.1007/bf01728908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In an in vitro study 246 clinical isolates of erythromycin-resistant staphylococci from six hospitals in Austria were investigated for susceptibility to josamycin and other, newer macrolide antibiotics, e.g. roxithromycin and clarithromycin. 71 strains of Staphylococcus aureus showed an MIC > or = 4 mg/l and 100 strains of S. aureus showed an MIC > or = 256 mg/l. In addition, 25 strains of coagulase-negative staphylococci resistant to erythromycin at an MIC of > or = 4 mg/l were investigated. At an MIC of 2 mg/l 57% of the erythromycin-resistant strains of S. aureus were inhibited by josamycin, 25% by clarithromycin and 11.6% by roxithromycin. At an MIC of 2 mg/l 13.3% of erythromycin-resistant coagulase-negative staphylococci were inhibited by josamycin, 10.7% by clarithromycin and 9.3% by roxithromycin. This study suggests that josamycin is still active in vitro against more than 50% of erythromycin-resistant strains of S. aureus. This drug is also more active than roxithromycin and clarithromycin against erythromycin-resistant S. aureus.
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Zech C, Staudinger R, Mühlbacher J, Glossmann H. Novel sites for phenylalkylamines: characterisation of a sodium-sensitive drug receptor with (-)-[3H]emopamil. Eur J Pharmacol 1991; 208:119-30. [PMID: 1800125 DOI: 10.1016/0922-4106(91)90062-m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
(-)-Emopamil ((S)-emopamil, (2S)-2-isopropyl-5-(methylphenethylamino)- 2-phenylvaleronitrile hydrochloride) is a Ca(2+)-antagonistic phenylalkylamine which also blocks serotonin (5-HT2) receptors and has antiischemic properties. The (-)-[3H]emopamil tissue distribution profile of specific binding is in striking contrast to that observed for (+)-[3H]PN 200-110 or (-)-[3H]desmethoxyverapamil: (-)-[3H]emopamil labels membrane fractions from guinea-pig liver much greater than adrenal gland greater than kidney approximately lung approximately ductus deferens approximately brain approximately skeletal muscle. Binding to liver membrane was saturable (KD = 12.8 nM, Bmax = 35 pmol/mg of protein), stereoselective, reversible (K-1 = 0.22 min-1 at 25 degrees C) and inhibited by tetraethylammonium (IC50: 1.8 mM) greater than Li+ (IC50: 12.5 mM) approximately Na+ (IC50: 13.6 mM) and [NH4+] (IC50: 79.3 mM) but not by Rb+, Cs+ or K+. The high-affinity liver membrane binding sites have a pharmacological profile that is distinct from the phenylalkylamine receptor domain of the voltage-dependent L-type Ca2+ channel. Similar sites exist in brain and other tissues, albeit with a lower density. Amiodarone, butoprozine and amiloride derivatives bind with high affinity whereas 1,4-dihydropyridines do not interact at all. It is suggested that the novel phenylalkylamine site is linked to a sodium-dependent carrier or transport system.
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Affiliation(s)
- C Zech
- Institut für Biochemische Pharmakologie, Innsbruck, Austria
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