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Kunze T, Dreßler C, Lauer C, Paul W, Sebastiani D. Reverse Mapping of Coarse Grained Polyglutamine Conformations from PRIME20 Sampling. Chemphyschem 2024; 25:e202300521. [PMID: 38314956 DOI: 10.1002/cphc.202300521] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
An inverse coarse-graining protocol is presented for generating and validating atomistic structures of large (bio-) molecules from conformations obtained via a coarse-grained sampling method. Specifically, the protocol is implemented and tested based on the (coarse-grained) PRIME20 protein model (P20/SAMC), and the resulting all-atom conformations are simulated using conventional biomolecular force fields. The phase space sampling at the coarse-grained level is performed with a stochastical approximation Monte Carlo approach. The method is applied to a series of polypeptides, specifically dimers of polyglutamine with varying chain length in aqueous solution. The majority (>70 %) of the conformations obtained from the coarse-grained peptide model can successfully be mapped back to atomistic structures that remain conformationally stable during 10 ns of molecular dynamics simulations. This work can be seen as the first step towards the overarching goal of improving our understanding of protein aggregation phenomena through simulation methods.
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Affiliation(s)
- Thomas Kunze
- Faculty of Natural Sciences II, Martin-Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle, Germany
| | - Christian Dreßler
- Institut für Physik, Ilmenau University of Technology, Weimarer Straße 32, 98693, Ilmenau, Germany
| | - Christian Lauer
- Faculty of Natural Sciences II, Martin-Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle, Germany
| | - Wolfgang Paul
- Faculty of Natural Sciences II, Martin-Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle, Germany
| | - Daniel Sebastiani
- Faculty of Natural Sciences II, Martin-Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle, Germany
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2
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Malik M, Demetrowitsch T, Schwarz K, Kunze T. New perspectives on 'Breathomics': metabolomic profiling of non-volatile organic compounds in exhaled breath using DI-FT-ICR-MS. Commun Biol 2024; 7:258. [PMID: 38431745 PMCID: PMC10908792 DOI: 10.1038/s42003-024-05943-x] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 02/20/2024] [Indexed: 03/05/2024] Open
Abstract
Breath analysis offers tremendous potential for diagnostic approaches, since it allows for easy and non-invasive sample collection. "Breathomics" as one major research field comprehensively analyses the metabolomic profile of exhaled breath providing insights into various (patho)physiological processes. Recent research, however, primarily focuses on volatile compounds. This is the first study that evaluates the non-volatile organic compounds (nVOCs) in breath following an untargeted metabolomic approach. Herein, we developed an innovative method utilizing a filter-based device for metabolite extraction. Breath samples of 101 healthy volunteers (female n = 50) were analysed using DI-FT-ICR-MS and biostatistically evaluated. The characterisation of the non-volatile core breathome identified more than 1100 metabolites including various amino acids, organic and fatty acids and conjugates thereof, carbohydrates as well as diverse hydrophilic and lipophilic nVOCs. The data shows gender-specific differences in metabolic patterns with 570 significant metabolites. Male and female metabolomic profiles of breath were distinguished by a random forest approach with an out-of-bag error of 0.0099. Additionally, the study examines how oral contraceptives and various lifestyle factors, like alcohol consumption, affect the non-volatile breathome. In conclusion, the successful application of a filter-based device combined with metabolomics-analyses delineate a non-volatile breathprint laying the foundation for discovering clinical biomarkers in exhaled breath.
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Affiliation(s)
- Madiha Malik
- Department of Clinical Pharmacy, Institute of Pharmacy, Kiel University, Kiel, Germany.
| | - Tobias Demetrowitsch
- Institute of Human Nutrition and Food Science, Food Technology, Kiel University, Kiel, Germany
- Kiel Network of Analytical Spectroscopy and Mass Spectrometry, Kiel University, Kiel, Germany
| | - Karin Schwarz
- Institute of Human Nutrition and Food Science, Food Technology, Kiel University, Kiel, Germany
- Kiel Network of Analytical Spectroscopy and Mass Spectrometry, Kiel University, Kiel, Germany
| | - Thomas Kunze
- Department of Clinical Pharmacy, Institute of Pharmacy, Kiel University, Kiel, Germany.
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Malik M, Kunze T. Detection of SARS-CoV-2 RNA in exhaled breath and its potential for prevention measures. Infect Prev Pract 2023; 5:100299. [PMID: 37520839 PMCID: PMC10374965 DOI: 10.1016/j.infpip.2023.100299] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/11/2023] [Indexed: 08/01/2023] Open
Abstract
Background To propose infection prevention measures it is essential to understand the dynamics of SARS-CoV-2 shedding, particularly in asymptomatic patients. This report compares the viral load progression in exhaled breath (EB) with the symptom severity. We aim to evaluate the adequacy of symptom assessment regarding the infectivity level of individuals. Methods We observed infected patients since their first positive test during hospitalization. EB samples were collected on days 1, 3, 5, 7, 10, 12 and 14 of hospitalization using a filter-based device. After extraction, viral loads were quantified with qRT-PCR. The infection trajectory was documented after symptom onset. Case Presentation and Discussion A 34-year old patient showed mild symptoms, e.g. fever, cough, headache, muscle pain and loss of taste and smell across trajectory of infection (Case 1). The viral loads emitted via exhaling were nearly constant and ranged from 8.6 x 103 and 4.1 x 104 RNA copies per hour. After the infection, the patient developed a pneumonia. The second case of a 65-year old patient depicted an asymptomatic infection trajectory for 14 days after the first diagnosis (Case 2). Nevertheless, the patient exhaled up to 2 x 105 SARS-CoV-2 virus copies hourly, approximately 10 fold higher than measured for Case 1. Conclusion Symptomatic and asymptomatic COVID-19 patients exhale distinctive amounts of SARS-CoV-2 not necessarily correlating with symptom severity. Particularly, asymptomatic patients might show higher EB viral shedding. Therefore, EB testing should be included in infection prevention measures as it has high potential to reveal the most infectious individuals regardless of their symptoms during infection.
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Affiliation(s)
- Madiha Malik
- Department Clinical Pharmacy, Institute of Pharmacy of Kiel University, Kiel, Germany
| | - Thomas Kunze
- Department Clinical Pharmacy, Institute of Pharmacy of Kiel University, Kiel, Germany
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Rixen S, Indorf PM, Kubitza C, Struwe MA, Klopp C, Scheidig AJ, Kunze T, Clement B. Reduction of Hydrogen Peroxide by Human Mitochondrial Amidoxime Reducing Component Enzymes. Molecules 2023; 28:6384. [PMID: 37687214 PMCID: PMC10489706 DOI: 10.3390/molecules28176384] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/23/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
The mitochondrial amidoxime reducing component (mARC) is a human molybdoenzyme known to catalyze the reduction of various N-oxygenated substrates. The physiological function of mARC enzymes, however, remains unknown. In this study, we examine the reduction of hydrogen peroxide (H2O2) by the human mARC1 and mARC2 enzymes. Furthermore, we demonstrate an increased sensitivity toward H2O2 for HEK-293T cells with an MTARC1 knockout, which implies a role of mARC enzymes in the cellular response to oxidative stress. H2O2 is a reactive oxygen species (ROS) formed in all living cells involved in many physiological processes. Furthermore, H2O2 constitutes the first mARC substrate without a nitrogen-oxygen bond, implying that mARC enzymes may have a substrate spectrum going beyond the previously examined N-oxygenated compounds.
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Affiliation(s)
- Sophia Rixen
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
| | - Patrick M. Indorf
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
| | - Christian Kubitza
- Department of Structural Biology, Zoological Institute, Kiel University, 24118 Kiel, Germany; (C.K.); (A.J.S.)
| | - Michel A. Struwe
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
- Department of Structural Biology, Zoological Institute, Kiel University, 24118 Kiel, Germany; (C.K.); (A.J.S.)
| | - Cathrin Klopp
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
- Department of Structural Biology, Zoological Institute, Kiel University, 24118 Kiel, Germany; (C.K.); (A.J.S.)
| | - Axel J. Scheidig
- Department of Structural Biology, Zoological Institute, Kiel University, 24118 Kiel, Germany; (C.K.); (A.J.S.)
| | - Thomas Kunze
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
| | - Bernd Clement
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Kiel University, 24118 Kiel, Germany; (S.R.); (P.M.I.); (M.A.S.); (C.K.); (T.K.)
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Codescu MA, Kunze T, Weiß M, Brehm M, Kornilov O, Sebastiani D, Nibbering ETJ. Ultrafast Proton Transfer Pathways Mediated by Amphoteric Imidazole. J Phys Chem Lett 2023; 14:4775-4785. [PMID: 37186569 DOI: 10.1021/acs.jpclett.3c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Imidazole, being an amphoteric molecule, can act both as an acid and as a base. This property enables imidazole, as an essential building block, to effectively facilitate proton transport in high-temperature proton exchange membrane fuel cells and in proton channel transmembrane proteins, enabling those systems to exhibit high energy conversion yields and optimal biological function. We explore the amphoteric properties of imidazole by following the proton transfer exchange reaction dynamics with the bifunctional photoacid 7-hydroxyquinoline (7HQ). We show with ultrafast ultraviolet-mid-infrared pump-probe spectroscopy how for imidazole, in contrast to expectations based on textbook knowledge of acid-base reactivity, the preferential reaction pathway is that of an initial proton transfer from 7HQ to imidazole, and only at a later stage a transfer from imidazole to 7HQ, completing the 7HQ tautomerization reaction. An assessment of the molecular distribution functions and first-principles calculations of proton transfer reaction barriers reveal the underlying reasons for our observations.
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Affiliation(s)
- Marius-Andrei Codescu
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Thomas Kunze
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Moritz Weiß
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Oleg Kornilov
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Erik T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
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Jirschitzka S, Girreser U, Kunze T. An Aza-michael Addition Product Causes Incompatibility Between Etacrynic Acid and Theophylline in a Paediatric Cardiological ICU. Pharmazie 2023; 78:27-30. [PMID: 37189271 DOI: 10.1691/ph.2023.2564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In a compatibility study of parenteral drugs commonly used in paediatric cardiological intensive care units, an unknown reaction product was found in a mixture of etacrynic acid and theophylline. The conditions in terms of the concentration of etacrynic acid and theophylline as well as the materials used corresponded to the conditions in the intensive care unit. Initially, the reaction product appeared as a significant and increasing peak in the chromatograms when determining the content of etacrynic acid and theophylline via HPLC. At the same time, the concentrations of both drugs decreased. A literature search in the chemical databases Reaxys® and Scifinder ® revealed a patent from 1967 describing an aza-Michael addition between etacrynic acid and theophylline to either N-7 or N-9. Using LC-MS/MS experiments, we were able to confirm that Michael-like reaction between etacrynic acid and theophylline occurs. To elucidate the exact structure of the reaction product we performed NMR experiments (COSY, HSQC and HMBC). With the acquired data we were finally able to identify the unknown compound as the N-7 substituted adduct [2-(2,3-dichloro-4-{2-[(1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl]butanoyl}phenoxy)acetic acid]. Our findings show that etacrynic acid and theophylline should not be mixed and should be administered through separate venous lines when infused.
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Affiliation(s)
- S Jirschitzka
- Department of Clinical Pharmacy, Pharmaceutical Institute, Christian-Albrechts-Universität, Kiel, Germany
| | - U Girreser
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-Universität, Kiel, Germany
| | - T Kunze
- Department of Clinical Pharmacy, Pharmaceutical Institute, Christian-Albrechts-Universität, Kiel, Germany;,
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7
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Jirschitzka S, Längle D, Lück H, Schade D, Kunze T. Combined physicochemical and functional assessment of pertuzumab integrity supports extended in-use stability. Arch Pharm (Weinheim) 2023:e2300072. [PMID: 36978206 DOI: 10.1002/ardp.202300072] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/30/2023]
Abstract
Pertuzumab (Perjeta®) is a monoclonal antibody approved for the treatment of HER2-positive breast cancer. Before treatment, the concentrate must be diluted to obtain the ready-to-use infusion solution. Data on the storage stabilities of these preparations are lacking but important for all healthcare professionals in the area of outpatient chemotherapy. The aim of this study was to investigate the storage stability of the ready-to-use infusion bags and the concentrates from once-opened vials over a period of up to 42 days. For a comprehensive and unambiguous assessment of pertuzumab's integrity, a panel of orthogonal analytical methods was employed, including a newly established mass spectrometry-based peptide mapping procedure along with a reporter gene assay for monitoring cellular bioactivity. The herein presented data showed that the ready-to-use infusion solutions stored at 4 ± 2°C and at 20 ± 3°C without light protection, as well as the undiluted Perjeta® concentrates stored at 4 ± 2°C, were physicochemically stable and biologically active for 28 days. These results might eventually allow for infusion preparations in advance, thus improving the quality of patient care as well as the economic usage of pertuzumab.
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Affiliation(s)
- Sven Jirschitzka
- Department of Clinical Pharmacy, Institute of Pharmacy, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Daniel Längle
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Hendrik Lück
- Hospital Pharmacy, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Dennis Schade
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Partner Site Kiel, DZHK, German Center for Cardiovascular Research, Kiel, Germany
| | - Thomas Kunze
- Department of Clinical Pharmacy, Institute of Pharmacy, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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8
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Kunze T, Dressler C, Sebastiani D. Secondary Structure Formation in Hybrid Synthetic/Peptide Polymers: Insights from Molecular Dynamics Simulations. MACROMOL THEOR SIMUL 2023. [DOI: 10.1002/mats.202200070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Thomas Kunze
- Martin‐Luther University Halle‐Wittenberg Institute for Physical Chemistry Von‐Danckelmann‐Platz 4 06120 Halle/Saale Germany
| | - Christian Dressler
- Martin‐Luther University Halle‐Wittenberg Institute for Physical Chemistry Von‐Danckelmann‐Platz 4 06120 Halle/Saale Germany
| | - Daniel Sebastiani
- Martin‐Luther University Halle‐Wittenberg Institute for Physical Chemistry Von‐Danckelmann‐Platz 4 06120 Halle/Saale Germany
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9
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Braig C, Sokolov A, Wilks RG, Kozina X, Kunze T, Bjeoumikhova S, Thiel M, Erko A, Bär M. Polycapillary-boosted instrument performance in the extreme ultraviolet regime for inverse photoemission spectroscopy: erratum. Opt Express 2022; 30:34935-34937. [PMID: 36242497 DOI: 10.1364/oe.473152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Indexed: 06/16/2023]
Abstract
We correct values and figures for the resolution of the spectrometer, as proposed in [Opt. Express25, 31840 (2017)10.1364/OE.25.031840OPEXFF1094-4087]. The new results take into account previously unknown, incoherent phase fluctuations, caused by the polycapillary lens (PCL), and estimate the realistic performance of the instrument.
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Malik M, Kunze AC, Bahmer T, Herget-Rosenthal S, Kunze T. SARS-CoV-2: Viral Loads of Exhaled Breath and Oronasopharyngeal Specimens in Hospitalized Patients with COVID-19. Int J Infect Dis 2021; 110:105-110. [PMID: 34242768 PMCID: PMC8260556 DOI: 10.1016/j.ijid.2021.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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: 05/10/2021] [Revised: 06/30/2021] [Accepted: 07/03/2021] [Indexed: 12/13/2022] Open
Abstract
Background SARS-CoV-2 seems mainly transmissible via respiratory droplets. We compared the time-dependent SARS-CoV-2 viral load in serial pharyngeal swab with exhaled breath (EB) samples of hospitalized COVID-19 patients. Methods In this prospective proof of concept study, we examined hospitalized patients who initially tested positive for SARS-CoV-2. Paired oronasopharyngeal swab and EB specimens were taken at different days of hospitalization. EB collection was performed through a simple, noninvasive method using an electret air filter-based device. SARS-CoV-2 RNA detection was determined with real-time quantitative reverse transcription polymerase chain reaction. Results Of 187 serial samples from 15 hospitalized patients, 87/87 oronasopharyngeal swabs and 70/100 EB specimens tested positive. Comparing the number of SARS-CoV-2 copies, the viral load of the oronasopharyngeal swabs was significantly higher (CI 99%, P<<0,001) than for EB samples. The mean viral load per swab was 7.97 × 106 (1.65 × 102-1.4 × 108), whereas EB samples showed 2.47 × 103 (7.19 × 101-2.94 × 104) copies per 20 times exhaling. Viral loads of paired oronasopharyngeal swab and EB samples showed no correlation. Conclusions Assessing the infectiousness of COVID-19 patients merely through pharyngeal swabs might not be accurate. Exhaled breath could represent a more suitable matrix for evaluating infectiousness and might allow screening for superspreader individuals and widespread variants such as Delta.
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Affiliation(s)
- Madiha Malik
- Department of Clinical Pharmacy, Pharmaceutical Institute, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany.
| | - Ann-Cathrin Kunze
- Department of Internal Medicine, Rotes Kreuz Krankenhaus, St.-Pauli-Deich 24, 28199 Bremen, Germany
| | - Thomas Bahmer
- Department of Internal Medicine I, Pulmonology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, 24105 Kiel, Germany
| | - Stefan Herget-Rosenthal
- Department of Internal Medicine, Rotes Kreuz Krankenhaus, St.-Pauli-Deich 24, 28199 Bremen, Germany
| | - Thomas Kunze
- Department of Clinical Pharmacy, Pharmaceutical Institute, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany.
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Alleaume C, Alamri S, Kunze T, Ziegler J, Wilson A, Bola R. Scatterometry and diffractometry techniques to monitor surfaces textured by rapid ultra-short pulse laser. J Phys Photonics 2020. [DOI: 10.1088/2515-7647/ab92b0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
The overall aim of the PROMETHEUS project is to develop high power ultra-short pulse lasers and the associated optics to enable the precise periodic texturing of surfaces to impart a range of surface functionalities at unprecedented processing speeds. The project focusses upon the industrial application of ultra-short pulse lasers for manufacturing and on the development of high power ultra-short pulse laser technologies in the range of 700 ps – 10 ns. In summary, new textures will be manufactured to achieve functional surfaces utilising fewer raw materials, less energy and less waste; improve accuracy, power and control over existing technologies; increase achievable precision and minimize heat impact on sensitive materials. This article will provide the outcomes of the first results achieved from the monitoring solutions being used to assess surface textures with micrometer resolution.
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12
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Indorf P, Kubitza C, Scheidig AJ, Kunze T, Clement B. Drug Metabolism by the Mitochondrial Amidoxime Reducing Component (mARC): Rapid Assay and Identification of New Substrates. J Med Chem 2020; 63:6538-6546. [PMID: 31790578 DOI: 10.1021/acs.jmedchem.9b01483] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For the development of new drugs, the investigation of their metabolism is of central importance. In the past, the focus was mostly on the consideration of established enzymes leading to oxidations such as cytochrome P450. However, reductive metabolism by the mARC enzyme system can play an important role in particular for nitrogen containing functional groups. A rapid test was established to give developers of new drugs in the preclinical stage the opportunity to test the metabolism by mARC. To demonstrate the relevance and validity of the new test system, known and potential substrates were applied to this new assay. All known substrates could be detected by the system. Furthermore, several new substrates were found including long-established drugs such as hydroxyurea and new compounds in development such as epacdadostat.
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Affiliation(s)
- Patrick Indorf
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Christian Kubitza
- Zoological Institute-Structural Biology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Axel J Scheidig
- Zoological Institute-Structural Biology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Thomas Kunze
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
| | - Bernd Clement
- Pharmaceutical Institute-Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstraße 76, 24118 Kiel, Germany
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Hartmann C, Gupta S, Bendikov T, Kozina X, Kunze T, Félix R, Hodes G, Wilks RG, Cahen D, Bär M. Impact of SnF 2 Addition on the Chemical and Electronic Surface Structure of CsSnBr 3. ACS Appl Mater Interfaces 2020; 12:12353-12361. [PMID: 32045207 PMCID: PMC7307835 DOI: 10.1021/acsami.9b22967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report on the chemical and electronic structure of cesium tin bromide (CsSnBr3) and how it is impacted by the addition of 20 mol % tin fluoride (SnF2) to the precursor solution, using both surface-sensitive lab-based soft X-ray photoelectron spectroscopy (XPS) and near-surface bulk-sensitive synchrotron-based hard XPS (HAXPES). To determine the reproducibility and reliability of conclusions, several (nominally identically prepared) sample sets were investigated. The effects of deposition reproducibility, handling, and transport are found to cause significant changes in the measured properties of the films. Variations in the HAXPES-derived compositions between individual sample sets were observed, but in general, they confirm that the addition of 20 mol % SnF2 improves coverage of the titanium dioxide substrate by CsSnBr3 and decreases the oxidation of SnII to SnIV while also suppressing formation of secondary Br and Cs species. Furthermore, the (surface) composition is found to be Cs-deficient and Sn-rich compared to the nominal stoichiometry. The valence band (VB) shows a SnF2-induced redistribution of Sn 5s-derived density of states, reflecting the changing SnII/SnIV ratio. Notwithstanding some variability in the data, we conclude that SnF2 addition decreases the energy difference between the VB maximum of CsSnBr3 and the Fermi level, which we explain by defect chemistry considerations.
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Affiliation(s)
- Claudia Hartmann
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
| | - Satyajit Gupta
- Department
of Materials & Interfaces, Weizmann
Institute of Science (WIS), 7610001 Rehovot, Israel
- Department
of Chemistry, Indian Institute of Technology
Bhilai, GEC Campus, Chhattisgarh 492015, India
| | - Tatyana Bendikov
- Chemical
Research Support Unit, Weizmann Institute
of Science (WIS), Rehovot 7610001, Israel
| | - Xeniya Kozina
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
| | - Thomas Kunze
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
| | - Roberto Félix
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
| | - Gary Hodes
- Department
of Materials & Interfaces, Weizmann
Institute of Science (WIS), 7610001 Rehovot, Israel
- E-mail: (G.H.)
| | - Regan G. Wilks
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
- Energy
Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
(HZB), 12489 Berlin, Germany
| | - David Cahen
- Department
of Materials & Interfaces, Weizmann
Institute of Science (WIS), 7610001 Rehovot, Israel
- E-mail: (D.C.)
| | - Marcus Bär
- Interface
Design, Helmholtz-Zentrum Berlin für
Materialien und Energie GmbH (HZB), 14109 Berlin, Germany
- Energy
Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
(HZB), 12489 Berlin, Germany
- Helmholtz-Institute
Erlangen-Nürnberg for Renewable Energy (HI ERN), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
- Department
of Chemistry & Pharmacy, Friedrich-Alexander-Universität
Erlangen-Nürnberg, 91058 Erlangen, Germany
- E-mail: (M.B.)
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14
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Malitckaya M, Kunze T, Komsa HP, Havu V, Handick E, Wilks RG, Bär M, Puska MJ. Alkali Postdeposition Treatment-Induced Changes of the Chemical and Electronic Structure of Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers: A First-Principle Perspective. ACS Appl Mater Interfaces 2019; 11:3024-3033. [PMID: 30592197 PMCID: PMC6727185 DOI: 10.1021/acsami.8b18216] [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] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
The effects of alkali postdeposition treatment (PDT) on the valence band structure of Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorbers are addressed from a first-principles perspective. In detail, experimentally derived hard X-ray photoelectron spectroscopy (HAXPES) data [ Handick , E. ; ACS Appl. Mater. Interfaces 2015 , 7 , 27414 - 27420 ] of the valence band structure of alkali-free and NaF/KF-PDT CIGSe are directly compared and fit by calculated density of states (DOS) of CuInSe2, its Cu-deficient counterpart CuIn5Se8, and different potentially formed secondary phases, such as KInSe2, InSe, and In2Se3. The DOSs are based on first-principles electronic structure calculations and weighted according to element-, symmetry-, and energy-dependent photoionization cross sections for the comparison to experimental data. The HAXPES spectra were recorded using photon energies ranging from 2 to 8 keV, allowing extraction of information from different sample depths. The analysis of the alkali-free CIGSe valence band structure reveals that it can best be described by a mixture of the DOS of CuInSe2 and CuIn5Se8, resulting in a stoichiometry slightly more Cu-rich than that of CuIn3Se5. The NaF/KF-PDT-induced changes in the HAXPES spectra for different alkali exposures are best reproduced by additional contributions from KInSe2, with some indications that the formation of a pronounced K-In-Se-type surface species might crucially depend on the amount of K available during PDT.
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Affiliation(s)
- Maria Malitckaya
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Thomas Kunze
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Hannu-Pekka Komsa
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Ville Havu
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
| | - Evelyn Handick
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Regan G. Wilks
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
| | - Marcus Bär
- Department
of Interface Design and Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH (HZB), 12489 Berlin, Germany
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy
(HIERN), Forschungszentrum Jülich, 90429 Erlangen, Germany
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Martti J. Puska
- Department of Applied
Physics, Aalto University, P.O. Box 11000, 00076 Aalto, Finland
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15
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Henriksson R, Järås J, Bergfeldt K, Sharp L, Ridderheim M, Degsell E, Kunze T. [Survival increases for all cancer diagnoses - but inequality persists]. Lakartidningen 2018; 115:E43P. [PMID: 29738056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
New data show a continuously increased five-year survival for almost all analyzed cancer diagnoses since 1990. It has to be emphasized that the figures are uncertain due to the limited number of patients. The variation is huge and the greatest improvements are seen not least among the three major tumor diseases (breast, colorectal and prostate cancer), where the society, industry and research bodies made the biggest investments over the years. The causes of improved survival can be sought in several areas, such as earlier detection and better treatments. In addition to survival estimates, it is also always of importance to consider aspects around patient related outcome, such as quality of life.
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Affiliation(s)
- Roger Henriksson
- Onkologi & Patologi - Regionalt Cancercentrum STOCKHOLM, Sweden Onkologi & Patologi - Regionalt Cancercentrum STOCKHOLM, Sweden
| | - Jacob Järås
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
| | - Kjell Bergfeldt
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
| | - Lena Sharp
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
| | - Mona Ridderheim
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
| | - Eskil Degsell
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
| | - Thomas Kunze
- Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden Regionalt cancercentrum Stockholm-Gotland regionen - Stockholm, Sweden
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16
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Häsler R, Kautz C, Rehman A, Podschun R, Gassling V, Brzoska P, Sherlock J, Gräsner JT, Hoppenstedt G, Schubert S, Ferlinz A, Lieb W, Laudes M, Heinsen FA, Scholz J, Harmsen D, Franke A, Eisend S, Kunze T, Fickenscher H, Ott S, Rosenstiel P, Schreiber S. The antibiotic resistome and microbiota landscape of refugees from Syria, Iraq and Afghanistan in Germany. Microbiome 2018; 6:37. [PMID: 29458422 PMCID: PMC5819293 DOI: 10.1186/s40168-018-0414-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/24/2018] [Indexed: 05/12/2023]
Abstract
BACKGROUND Multidrug-resistant bacteria represent a substantial global burden for human health, potentially fuelled by migration waves: in 2015, 476,649 refugees applied for asylum in Germany mostly as a result of the Syrian crisis. In Arabic countries, multiresistant bacteria cause significant problems for healthcare systems. Currently, no data exist describing antibiotic resistances in healthy refugees. Here, we assess the microbial landscape and presence of antibiotic resistance genes (ARGs) in refugees and German controls. To achieve this, a systematic study was conducted in 500 consecutive refugees, mainly from Syria, Iraq, and Afghanistan and 100 German controls. Stool samples were subjected to PCR-based quantification of 42 most relevant ARGs, 16S ribosomal RNA gene sequencing-based microbiota analysis, and culture-based validation of multidrug-resistant microorganisms. RESULTS The fecal microbiota of refugees is substantially different from that of resident Germans. Three categories of resistance profiles were found: (i) ARGs independent of geographic origin of individuals comprising BIL/LAT/CMA, ErmB, and mefE; (ii) vanB with a high prevalence in Germany; and (iii) ARGs showing substantially increased prevalences in refugees comprising CTX-M group 1, SHV, vanC1, OXA-1, and QnrB. The majority of refugees carried five or more ARGs while the majority of German controls carried three or less ARGs, although the observed ARGs occurred independent of signatures of potential pathogens. CONCLUSIONS Our results, for the first time, assess antibiotic resistance genes in refugees and demonstrate a substantially increased prevalence for most resistances compared to German controls. The antibiotic resistome in refugees may thus require particular attention in the healthcare system of host countries.
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Affiliation(s)
- Robert Häsler
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Christian Kautz
- Pharmaceutical Institute, Department of Clinical Pharmacy, Christian Albrecht University of Kiel, Kiel, Germany
| | - Ateequr Rehman
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Rainer Podschun
- Institute of Infection Medicine, Christian Albrecht University of Kiel, Kiel, Germany
| | - Volker Gassling
- Department of Oral and Maxillofacial Surgery, University Hospital of Schleswig-Holstein, Kiel, Germany
| | - Pius Brzoska
- Thermo Fisher Scientific, San Francisco, CA, USA
| | - Jon Sherlock
- Thermo Fisher Scientific, San Francisco, CA, USA
| | - Jan-Thorsten Gräsner
- Department of Anaesthesia and Intensive Care Medicine, University Hospital of Schleswig-Holstein, Kiel, Germany
| | - Gesine Hoppenstedt
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Sabine Schubert
- Institute of Infection Medicine, Christian Albrecht University of Kiel, Kiel, Germany
| | - Astrid Ferlinz
- Thermo Fisher Scientific, Life Technologies GmbH, Darmstadt, Germany
| | - Wolfgang Lieb
- POPGEN Biobank and Institute of Epidemiology, Christian Albrecht University of Kiel, Kiel, Germany
| | - Matthias Laudes
- POPGEN Biobank and Institute of Epidemiology, Christian Albrecht University of Kiel, Kiel, Germany
| | - Femke-Anouska Heinsen
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Jens Scholz
- Department of Anaesthesia and Intensive Care Medicine, University Hospital of Schleswig-Holstein, Kiel, Germany
| | - Dag Harmsen
- Department of Periodontology and Restorative Dentistry, University Hospital Münster, Münster, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Swantje Eisend
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Thomas Kunze
- Pharmaceutical Institute, Department of Clinical Pharmacy, Christian Albrecht University of Kiel, Kiel, Germany
| | - Helmut Fickenscher
- Institute of Infection Medicine, Christian Albrecht University of Kiel, Kiel, Germany
| | - Stephan Ott
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Philip Rosenstiel
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany.
| | - Stefan Schreiber
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Christian Albrecht University of Kiel, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany.
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany.
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17
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Nicoara N, Kunze T, Jackson P, Hariskos D, Duarte RF, Wilks RG, Witte W, Bär M, Sadewasser S. Evidence for Chemical and Electronic Nonuniformities in the Formation of the Interface of RbF-Treated Cu(In,Ga)Se 2 with CdS. ACS Appl Mater Interfaces 2017; 9:44173-44180. [PMID: 29178776 DOI: 10.1021/acsami.7b12448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the initial stages of CdS buffer layer formation on Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorbers subjected to rubidium fluoride (RbF) postdeposition treatment (PDT). A detailed characterization of the CIGSe/CdS interface for different chemical bath deposition (CBD) times of the CdS layer is obtained from spatially resolved atomic and Kelvin probe force microscopy and laterally integrating X-ray spectroscopies. The observed spatial inhomogeneity in the interface's structural, chemical, and electronic properties of samples undergoing up to 3 min of CBD treatments is indicative of a complex interface formation including an incomplete coverage and/or nonuniform composition of the buffer layer. It is expected that this result impacts solar cell performance, in particular when reducing the CdS layer thickness (e.g., in an attempt to increase the collection in the ultraviolet wavelength region). Our work provides important findings on the absorber/buffer interface formation and reveals the underlying mechanism for limitations in the reduction of the CdS thickness, even when an alkali PDT is applied to the CIGSe absorber.
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Affiliation(s)
- Nicoleta Nicoara
- International Iberian Nanotechnology Laboratory (INL) , 4715-330 Braga, Portugal
| | - Thomas Kunze
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
| | - Philip Jackson
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Dimitrios Hariskos
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Roberto Félix Duarte
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
| | - Regan G Wilks
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany
| | - Wolfram Witte
- Zentrum für Sonnenenergie-und Wasserstoff-Forschung Baden-Württemberg (ZSW) , 70563 Stuttgart, Germany
| | - Marcus Bär
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany
- Institut für Physik, Brandenburgische Technische Universität Cottbus-Senftenberg , 03046 Cottbus, Germany
| | - Sascha Sadewasser
- International Iberian Nanotechnology Laboratory (INL) , 4715-330 Braga, Portugal
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18
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Braig C, Sokolov A, Wilks RG, Kozina X, Kunze T, Bjeoumikhova S, Thiel M, Erko A, Bär M. Polycapillary-boosted instrument performance in the extreme ultraviolet regime for inverse photoemission spectroscopy. Opt Express 2017; 25:31840-31852. [PMID: 29245854 DOI: 10.1364/oe.25.031840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/27/2017] [Indexed: 06/07/2023]
Abstract
A collimating polycapillary half lens, traditionally used in the medium and hard X-ray band, is operated at a photon energy of 36 eV for the first time. While the transmission still exceeds 50%, the measured and simulated spatial resolution and angular divergence approach 0.4 mm or less and at most 20 mrad, respectively. This unexpected, superior performance of the polycapillary optic in the extreme Ultraviolet could enable the design of an efficient, versatile and compact spectrometer for inverse photoemission spectroscopy (IPES): Its wavelength-dispersive component, a customized reflection zone plate, can maintain an energy resolution of 0.3 eV, whereas the sensitivity may be enhanced by more than one order of magnitude, compared to conventional spectrometers. Furthermore, the overall length of 0.9 m would allow for an eased alignment and evacuation. We see a significant potential for numerous polycapillary-based XUV / soft X-ray instruments in the future, in particular after further optimization for this long wavelength regime.
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19
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Lühr I, Kunze T, Mundhenke C, Maass N, Erhart T, Denker M, Beckmann D, Tiemann M, Schulte C, Dohrmann P, Cavaillé F, Godeau F, Gespach C, Gieseler F. Activated coagulation factors in human malignant effusions and their contribution to cancer cell metastasis and therapy. Thromb Haemost 2017. [DOI: 10.1160/th06-12-0712] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SummaryWe have shown that the thrombin G-protein coupled receptors (GPCR) designated as protease-activated receptors (PAR-1) are expressed in primary cancer cells isolated from peritoneal and pleural malignant effusions. Here, our main goal was to evaluate several coagulation and thrombin activation effectors and markers in a series of 136 malignant effusions from cancer patients with gastrointestinal, lung and mammary carcinomas. All these patients present a highly activated coagulation system in blood and their malignant effusions, as indicated by high levels of prothrombin F1.2 fragments and D-dimers. Notably, we detected in the effusions all the coagulation factors of the tissue factor pathway inducing thrombin activation, namely factorsVII, V, X and II, as well as high VEGF levels and IGF-II in mature and precursor forms. Fibrin clot formation also correlated with higher levels of free ionized calcium (iCa), suggesting that iCa and its binding protein albumin are regulatory factors for fibrinogenesis in effusions. Consequently, thrombin,VEGF and IGFII appear to converge in the promotion of survival and invasivity of the metastatic cancer cells from blood to the malignant effusions. Thus, we add new insights on the interconnections between blood coagulation disorders in cancer patients and thrombin activation in malignant effusions, including their functional interaction with PAR in metastatic cancer cells. Based on these data we propose to counteract the metastatic cascades by targeted invalidation of key effectors of the coagulation system. Therefore, potential therapeutic approaches include the application of thrombin protease inhibitors, VEGF-blocking antibodies, and drugs targeting the VEGF and thrombin signaling pathways, such as tyrosine kinase or GPCR inhibitors.
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20
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Handick E, Reinhard P, Wilks RG, Pianezzi F, Kunze T, Kreikemeyer-Lorenzo D, Weinhardt L, Blum M, Yang W, Gorgoi M, Ikenaga E, Gerlach D, Ueda S, Yamashita Y, Chikyow T, Heske C, Buecheler S, Tiwari AN, Bär M. Formation of a K-In-Se Surface Species by NaF/KF Postdeposition Treatment of Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers. ACS Appl Mater Interfaces 2017; 9:3581-3589. [PMID: 28058843 DOI: 10.1021/acsami.6b11892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A NaF/KF postdeposition treatment (PDT) has recently been employed to achieve new record efficiencies of Cu(In,Ga)Se2 (CIGSe) thin film solar cells. We have used a combination of depth-dependent soft and hard X-ray photoelectron spectroscopy as well as soft X-ray absorption and emission spectroscopy to gain detailed insight into the chemical structure of the CIGSe surface and how it is changed by different PDTs. Alkali-free CIGSe, NaF-PDT CIGSe, and NaF/KF-PDT CIGSe absorbers grown by low-temperature coevaporation have been interrogated. We find that the alkali-free and NaF-PDT CIGSe surfaces both display the well-known Cu-poor CIGSe chemical surface structure. The NaF/KF-PDT, however, leads to the formation of bilayer structure in which a K-In-Se species covers the CIGSe compound that in composition is identical to the chalcopyrite structure of the alkali-free and NaF-PDT absorber.
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Affiliation(s)
- Evelyn Handick
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Patrick Reinhard
- Laboratory of Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials and Science and Technology , Überlandstraße 129, 8600 Dübendorf, Switzerland
| | - Regan G Wilks
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Fabian Pianezzi
- Laboratory of Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials and Science and Technology , Überlandstraße 129, 8600 Dübendorf, Switzerland
| | - Thomas Kunze
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Dagmar Kreikemeyer-Lorenzo
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Lothar Weinhardt
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 S. Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - Monika Blum
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 S. Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - Wanli Yang
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Mihaela Gorgoi
- Energy Materials In-Situ Laboratory Berlin, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institute for Nanospectroscopy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Eiji Ikenaga
- SPring-8/JASRI , 1-1-1 Koto, Sayo-cho, Hyogo 679-5198, Japan
| | - Dominic Gerlach
- MANA/Nano-Electronics Materials Unit, National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Shigenori Ueda
- Synchrotron X-ray Station at SPring-8 , NIMS. 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148, Japan
- Quantum Beam Unit , NIMS, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Yoshiyuki Yamashita
- MANA/Nano-Electronics Materials Unit, National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Toyohiro Chikyow
- MANA/Nano-Electronics Materials Unit, National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Clemens Heske
- Institute for Photon Science and Synchrotron Radiation (IPS) and Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 S. Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - Stephan Buecheler
- Laboratory of Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials and Science and Technology , Überlandstraße 129, 8600 Dübendorf, Switzerland
| | - Ayodhya N Tiwari
- Laboratory of Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials and Science and Technology , Überlandstraße 129, 8600 Dübendorf, Switzerland
| | - Marcus Bär
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) , Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Energy Materials In-Situ Laboratory Berlin, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg , Platz der Deutschen Einheit 1, 03046 Cottbus, Germany
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21
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Gersonde F, Eisend S, Haake N, Kunze T. Physicochemical compatibility and emulsion stability of propofol with commonly used analgesics and sedatives in an intensive care unit. Eur J Hosp Pharm 2016; 24:293-303. [PMID: 31156960 DOI: 10.1136/ejhpharm-2016-001038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [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: 06/30/2016] [Revised: 08/26/2016] [Accepted: 08/31/2016] [Indexed: 11/04/2022] Open
Abstract
Objectives The purpose of this study was the determination of the physicochemical compatibility and emulsion stability of propofol with other sedatives and analgesics (clonidine hydrochloride, dexmedetomidine, 4-hydroxybutyric acid, (S)-ketamine, lormetazepam, midazolam hydrochloride, piritramide, remifentanil hydrochloride and sufentanil citrate) that are frequently administered together intravenously. Methods Drugs were mixed with propofol and stored without light protection at room temperature. Samples were taken at 10 points of time over 7 days. The physical stability and emulsion stability in particular were analysed by visual and microscopical inspection and by measurement of the pH value, zeta potential and globule size distribution. In addition, high-performance liquid chromatography and mass spectrometry were used to identify chemical incompatibilities. Results 4-Hydroxybutyric acid, midazolam hydrochloride, piritramide and remifentanil hydrochloride are physically incompatible when mixed with propofol. The reason for this is the development of an increased fraction of oil droplets >5 µm leading to a higher risk of emboli. Moreover, propofol is chemically incompatible with remifentanil. The sorption of propofol to the rubber stopper of the syringe was another detectable incompatibility. Conclusions Propofol should not be administered with 4-hydroxybutyric acid, remifentanil hydrochloride, midazolam hydrochloride and piritramide through the same intravenous line. Based on the risk of sorption to the rubber material, propofol should be used with caution. A drug loss might occur that leads to an underdosing of the patient requiring a dose adjustment to avoid any adverse consequences. As a result of this study, the drug safety in intensive care units could be optimised.
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Affiliation(s)
- Franziska Gersonde
- Department of Clinical Pharmacy, Pharmaceutical Institute, Kiel University, Kiel, Germany
| | - Swantje Eisend
- Hospital Pharmacy, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Nils Haake
- Department of Intensive Care, Imland Hospital Rendsburg, Rendsburg, Germany
| | - Thomas Kunze
- Department of Clinical Pharmacy, Pharmaceutical Institute, Kiel University, Kiel, Germany
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Plitzko B, Havemeyer A, Kunze T, Clement B. The pivotal role of the mitochondrial amidoxime reducing component 2 in protecting human cells against apoptotic effects of the base analog N6-hydroxylaminopurine. J Biol Chem 2015; 290:10126-35. [PMID: 25713076 DOI: 10.1074/jbc.m115.640052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 01/21/2015] [Indexed: 12/27/2022] Open
Abstract
N-Hydroxylated nucleobases and nucleosides as N-hydroxylaminopurine (HAP) or N-hydroxyadenosine (HAPR) may be generated endogenously in the course of cell metabolism by cytochrome P450, by oxidative stress or by a deviating nucleotide biosynthesis. These compounds have shown to be toxic and mutagenic for procaryotic and eucaryotic cells. For DNA replication fidelity it is therefore of great importance that organisms exhibit effective mechanisms to remove such non-canonical base analogs from DNA precursor pools. In vitro, the molybdoenzymes mitochondrial amidoxime reducing component 1 and 2 (mARC1 and mARC2) have shown to be capable of reducing N-hydroxylated base analogs and nucleoside analogs to the corresponding canonical nucleobases and nucleosides upon reconstitution with the electron transport proteins cytochrome b5 and NADH-cytochrome b5 reductase. By RNAi-mediated down-regulation of mARC in human cell lines the mARC-dependent N-reductive detoxication of HAP in cell metabolism could be demonstrated. For HAPR, on the other hand, the reduction to adenosine seems to be of less significance in the detoxication pathway of human cells as HAPR is primarily metabolized to inosine by direct dehydroxylamination catalyzed by adenosine deaminase. Furthermore, the effect of mARC knockdown on sensitivity of human cells to HAP was examined by flow cytometric quantification of apoptotic cell death and detection of poly (ADP-ribose) polymerase (PARP) cleavage. mARC2 was shown to protect HeLa cells against the apoptotic effects of the base analog, whereas the involvement of mARC1 in reductive detoxication of HAP does not seem to be pivotal.
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Affiliation(s)
- Birte Plitzko
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Antje Havemeyer
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Thomas Kunze
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Bernd Clement
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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Ott G, Plitzko B, Krischkowski C, Reichmann D, Bittner F, Mendel RR, Kunze T, Clement B, Havemeyer A. Reduction of Sulfamethoxazole Hydroxylamine (SMX-HA) by the Mitochondrial Amidoxime Reducing Component (mARC). Chem Res Toxicol 2014; 27:1687-95. [DOI: 10.1021/tx500174u] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Gudrun Ott
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Birte Plitzko
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Carmen Krischkowski
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Debora Reichmann
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Florian Bittner
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Ralf R. Mendel
- Department
of Plant Biology, Braunschweig University of Technology, Humboldtstrasse
1, D-38106 Braunschweig, Germany
| | - Thomas Kunze
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Bernd Clement
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
| | - Antje Havemeyer
- Department
of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
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Knudsen L, Eisend S, Haake N, Kunze T. Physicochemical compatibility of commonly used analgesics and sedatives in the intensive care medicine. Eur J Hosp Pharm 2014. [DOI: 10.1136/ejhpharm-2014-000444] [Citation(s) in RCA: 7] [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: 11/03/2022] Open
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Ott G, Reichmann D, Boerger C, Cascorbi I, Bittner F, Mendel RR, Kunze T, Clement B, Havemeyer A. Functional characterization of protein variants encoded by nonsynonymous single nucleotide polymorphisms in MARC1 and MARC2 in healthy Caucasians. Drug Metab Dispos 2014; 42:718-25. [PMID: 24423752 DOI: 10.1124/dmd.113.055202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human molybdenum-containing enzyme mitochondrial amidoxime reducing component (mARC), cytochrome b5 type B, and NADH cytochrome b5 reductase form an N-reductive enzyme system that is capable of reducing N-hydroxylated compounds. Genetic variations are known, but their functional relevance is unclear. Our study aimed to investigate the incidence of nonsynonymous single nucleotide polymorphisms (SNPs) in the mARC genes in healthy Caucasian volunteers, to determine saturation of the protein variants with molybdenum cofactor (Moco), and to characterize the kinetic behavior of the protein variants by in vitro biotransformation studies. Genotype frequencies of six SNPs in the mARC genes (c.493A>G, c.560T>A, c.736T>A, and c.739G>C in MARC1; c.730G>A and c.735T>G in MARC2) were determined by pyrosequencing in a cohort of 340 healthy Caucasians. Protein variants were expressed in Escherichia coli. Saturation with Moco was determined by measurement of molybdenum by inductively coupled mass spectrometry. Steady state assays were performed with benzamidoxime. The six variants were of low frequency in this Caucasian population. Only one homozygous variant (c.493A; MARC1) was detected. All protein variants were able to bind Moco. Steady state assays showed statistically significant decreases of catalytic efficiency values for the mARC-2 wild type compared with the mARC-1 wild type (P < 0.05) and for two mARC-2 variants compared with the mARC-2 wild type (G244S, P < 0.05; C245W, P < 0.05). After simultaneous substitution of more than two amino acids in the mARC-1 protein, N-reductive activity was decreased 5-fold. One homozygous variant of MARC1 was detected in our sample. The encoded protein variant (A165T) showed no different kinetic parameters in the N-reduction of benzamidoxime.
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Affiliation(s)
- Gudrun Ott
- Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Kiel, Germany (G.O., T.K., B.C., A.H.); Department of Plant Biology, Technical University of Braunschweig, Braunschweig, Germany (D.R., F.B., R.-R.M.); and Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany (C.B., I.C.)
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Daralammouri Y, Fuhrmann J, Kunze T. Giant right coronary artery aneurysm with a huge intramural thrombus. J Thorac Cardiovasc Surg 2013; 146:1290-1. [DOI: 10.1016/j.jtcvs.2013.02.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 02/16/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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Lühr I, Friedl A, Overath T, Tholey A, Kunze T, Hilpert F, Sebens S, Arnold N, Rösel F, Oberg HH, Maass N, Mundhenke C, Jonat W, Bauer M. Mammary fibroblasts regulate morphogenesis of normal and tumorigenic breast epithelial cells by mechanical and paracrine signals. Cancer Lett 2012; 325:175-88. [PMID: 22776560 DOI: 10.1016/j.canlet.2012.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/27/2012] [Accepted: 06/30/2012] [Indexed: 01/24/2023]
Abstract
Stromal factors play a critical role in the development of the mammary gland. Using a three dimensional-coculture model we demonstrate a significant role for stromal fibroblasts in the regulation of normal mammary epithelial morphogenesis and the control of tumor growth. Both soluble factors secreted by fibroblasts and fibroblast-derived modifications of the matrix compliance contribute to the regulation of epithelial cell morphogenesis. Readjustment of matrix tension by fibroblasts can even induce a phenotypic reversion of breast carcinoma cells. These data offer a basis to develop new strategies for the normalization of the tumor stroma as an innovative target in cancer therapy.
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Affiliation(s)
- Inke Lühr
- Department of Gynecology and Obstetrics, University Medical Center Schleswig-Holstein, Christian-Albrechts University, Kiel, Germany
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Luehr I, Klein A, Pospisil H, Standfuss C, Kunze T, Hilpert F, Mundhenke C, Jonat W, Bauer M. Evaluation of gene expression signatures induced by stromal factors as a predictor of survival in breast cancer. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.10607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Blume LF, Denker M, Gieseler F, Kunze T. Temperature corrected transepithelial electrical resistance (TEER) measurement to quantify rapid changes in paracellular permeability. Pharmazie 2010; 65:19-24. [PMID: 20187574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Determining the transepithelial electrical resistance (TEER) is a widely used method to functionally analyze tight junction dynamics in cell culture models of physiological barriers. Changes in temperature are known to have strong effects on TEER and can pose problems during the process of TEER measurements in cell culture vessels, complicating comparisons of TEER data across different experiments and studies. Here, we set out to devise a strategy to obtain temperature-independent TEER values based on the physical correlation between parameters such as TEER, temperature, medium viscosity and pore size of the cell culture inserts. By measuring the impact of temperature and different electrode types on TEER measurements on Caco-2 and HPDE (normal human pancreatic ductal epithelium) monolayers, we were able to derive a mathematical method that is suitable for the correction of TEER values for temperature changes. Applying this method to raw TEER values yields temperature-corrected TEER (tcTEER) values. Validity of tcTEER was demonstrated by showing a direct correlation with permeability of monolayers as determined by flux of RITC dextran. Taken together, the mathematical solution presented here allows for a simple and accurate determination of paracellular permeability independent of temperature variation during the process of TEER recording.
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Affiliation(s)
- L-F Blume
- Institute of Pharmacy, University of Kiel, Germany
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Bürenheide A, Kunze T, Clement B. Inhibitory Effects on Cytochrome P450 Enzymes of Pentamidine and Its Amidoxime Pro-Drug. Basic Clin Pharmacol Toxicol 2008; 103:61-5. [DOI: 10.1111/j.1742-7843.2008.00236.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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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Gieseler F, Stelck B, Blume LF, Denker M, Dohrmann P, Mundhenke C, Bauerschlag D, Tiemann M, Kunze T. [Coagulation and formation of malignant effusions]. Hamostaseologie 2007; 27:273-277. [PMID: 17938766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Malignant effusions are a frequent problem for cancer patients. Due to the high resistance of tumor cells within these effusions, no effective treatment has been defined yet. Most patients exhibit additional phenomena related to hyper-coagulability such as elevated levels for d-dimers and prothrombin fragments f1.2; half of them suffer from manifest thrombosis or complications. We followed the hypothesis that the activated coagulation system contributes to the resistance of tumor cells and analyzed the effusions from cancer patients. The majority of isolated tumor cells aberrantly expressed PAR-1 thrombin receptors. In vitro pre-incubation of PAR-1 expressing human leukemia cells with thrombin resulted in a dose-dependent resistance to idarubicin. Within the effusions, we did not only find high concentrations of VEGF and tissue factor, but also all coagulation factors of the tissue factor pathway. Very high levels of prothrombin fragments f1.2 indicate constant thrombin generation. Upon the basis of these findings, we developed a multistep model elucidating the pathophysiological generation of malignant effusions, which might serve as a basis for further examinations.
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Affiliation(s)
- F Gieseler
- Onkologischer Schwerpunkt, Klinik für Allgemeine Innere Medizin, Universitätsklinikum Schleswig-Holstein, Schittenhelmstr. 12, 24015 Kiel.
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Gieseler F, Lühr I, Kunze T, Mundhenke C, Maass N, Erhart T, Denker M, Beckmann D, Tiemann M, Schulte C, Dohrmann P, Cavaillé F, Godeau F, Gespach C. Activated coagulation factors in human malignant effusions and their contribution to cancer cell metastasis and therapy. Thromb Haemost 2007; 97:1023-30. [PMID: 17549306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We have shown that the thrombin G-protein coupled receptors (GPCR) designated as protease-activated receptors (PAR-1) are expressed in primary cancer cells isolated from peritoneal and pleural malignant effusions. Here, our main goal was to evaluate several coagulation and thrombin activation effectors and markers in a series of 136 malignant effusions from cancer patients with gastrointestinal, lung and mammary carcinomas. All these patients present a highly activated coagulation system in blood and their malignant effusions, as indicated by high levels of prothrombin F1.2 fragments and D-dimers. Notably, we detected in the effusions all the coagulation factors of the tissue factor pathway inducing thrombin activation, namely factors VII, V, X and II, as well as high VEGF levels and IGF-II in mature and precursor forms. Fibrin clot formation also correlated with higher levels of free ionized calcium (iCa), suggesting that iCa and its binding protein albumin are regulatory factors for fibrinogenesis in effusions. Consequently, thrombin, VEGF and IGFII appear to converge in the promotion of survival and invasivity of the metastatic cancer cells from blood to the malignant effusions. Thus, we add new insights on the interconnections between blood coagulation disorders in cancer patients and thrombin activation in malignant effusions, including their functional interaction with PAR in metastatic cancer cells. Based on these data we propose to counteract the metastatic cascades by targeted invalidation of key effectors of the coagulation system. Therefore, potential therapeutic approaches include the application of thrombin protease inhibitors, VEGF-blocking antibodies, and drugs targeting the VEGF and thrombin signaling pathways, such as tyrosine kinase or GPCR inhibitors.
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Affiliation(s)
- Frank Gieseler
- University Hospital of Kiel, Schittenhelmstr. 12, 24105 Kiel, Germany.
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Stelck B, Blume LF, Denker M, Dohrmann P, Mundhenke C, Bauerschlag D, Tiemann M, Kunze T, Gieseler F. Die Rolle des Gerinnungssystems bei der Entstehung maligner Ergüsse. Hamostaseologie 2007. [DOI: 10.1055/s-0037-1617093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
ZusammenfassungMaligne Ergüsse sind ein typisches Problem von Patienten mit fortgeschrittenen Tumorerkrankungen, eine Behandlung wird durch eine hohe Zytostatikaresistenz der Tumorzellen erschwert. Viele Patienten leiden an einer gleichzeitig bestehenden Hyperkoagulabilität mit hohen Spiegeln für D-Dimer und Prothrombin Fragment F1.2, etwa die Hälfte an Thrombosen und deren Folgeerkrankungen. Wir haben die Hypothese verfolgt, dass ein aktiviertes Gerinnungssystem eine der Ursachen für die hohe Zytostatikaresistenz der Tumorzellen darstellt und haben die Ergüsse von Tumorpatienten weiter untersucht. Die isolierten Tumorzellen zeigten zum großen Teil ein aberrante Expression des Thrombinrezeptors PAR-1. Durch Vorinkubation mit Thrombin konnte dosisabhängig eine komplette Resistenz gegen das Zytostatikum Idarubicin (IC50) erreicht werden. In den Ergüssen fanden wir, neben sehr hohen Konzentrationen von VEGF und Tissue-Faktor, sämtliche Faktoren des Tissue-Faktor-Pathways. Eine starke Thrombinaktivierung konnte durch hohe Spiegel von Prothrombin Fragment F1.2 nachgewiesen werden. Wir präsentieren ein Modell der Entstehung maligner Ergüsse, das als Basis für weitere Untersuchungen geeignet ist.
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Havemeyer A, Bittner F, Wollers S, Mendel R, Kunze T, Clement B. Identification of the Missing Component in the Mitochondrial Benzamidoxime Prodrug-converting System as a Novel Molybdenum Enzyme. J Biol Chem 2006; 281:34796-802. [PMID: 16973608 DOI: 10.1074/jbc.m607697200] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [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: 11/06/2022] Open
Abstract
Amidoximes can be used as prodrugs for amidines and related functional groups to enhance their intestinal absorption. These prodrugs are reduced to their active amidines. Other N-hydroxylated structures are mutagenic or responsible for toxic effects of drugs and are detoxified by reduction. In this study, a N-reductive enzyme system of pig liver mitochondria using benzamidoxime as a model substrate was identified. A protein fraction free from cytochrome b5 and cytochrome b5 reductase was purified, enhancing 250-fold the minor benzamidoxime-reductase activity catalyzed by the membrane-bound cytochrome b5/NADH cytochrome b5 reductase system. This fraction contained a 35-kDa protein with homologies to the C-terminal domain of the human molybdenum cofactor sulfurase. Here it was demonstrated that this 35-kDa protein contains molybdenum cofactor and forms the hitherto ill defined third component of the N-reductive complex in the outer mitochondrial membrane. Thus, the 35-kDa protein represents a novel group of molybdenum proteins in eukaryotes as it forms the catalytic part of a three-component enzyme complex consisting of separate proteins. Supporting these findings, recombinant C-terminal domain of the human molybdenum cofactor sulfurase exhibited N-reductive activity in vitro, which was strictly dependent on molybdenum cofactor.
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Affiliation(s)
- Antje Havemeyer
- Pharmaceutical Institute, Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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Clement B, Kunze T, Heberling S. Reduction of Nomega-hydroxy-L-arginine to L-arginine by pig liver microsomes, mitochondria, and human liver microsomes. Biochem Biophys Res Commun 2006; 349:869-73. [PMID: 16959215 DOI: 10.1016/j.bbrc.2006.08.123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 08/22/2006] [Indexed: 11/18/2022]
Abstract
Nomega-Hydroxy-L-arginine, the intermediate in nitric oxide formation from L-arginine catalyzed by NO synthase, can be released into the extracellular space. It has been suggested that it can circulate and exert paracrine effects. Since it cannot only be used as substrate by NO synthases, but can also be oxidized by cytochrome P450 and other hemoproteins in a superoxide-dependent manner, it has been proposed that it can serve as NO donor. In the present study, the in vitro reduction of Nomega-hydroxy-L-arginine was examined. Pig and human liver microsomes as well as pig liver mitochondria were capable of reducing Nomega-hydroxy-L-arginine to L-arginine in an oxygen-insensitive enzymatic reaction. These results demonstrate that this metabolic pathway has to be considered when suggesting Nomega-hydroxy-L-arginine as NO-precursor. The reconstituted liver microsomal system of a pig liver CYP2D enzyme, the benzamidoxime reductase, was unable to replace microsomes to produce L-arginine from Nomega-hydroxy-L-arginine.
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Affiliation(s)
- Bernd Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität zu Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany.
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Zebothsen I, Kunze T, Clement B. Inhibitory effects of cytostatically active 6-aminobenzo[c]phenanthridines on cytochrome P450 enzymes in human hepatic microsomes. Basic Clin Pharmacol Toxicol 2006; 99:37-43. [PMID: 16867169 DOI: 10.1111/j.1742-7843.2006.pto_337.x] [Citation(s) in RCA: 1] [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: 11/29/2022]
Abstract
Besides assays for the evaluation of efficacy new drug candidates have to undergo extensive testings for enhancement of pharmaceutical drug safety and optimization of application. The objective of the present work was to investigate the pharmacokinetic drug drug interaction potential for the cytostatically active 6-aminobenzo[c]phenanthridines BP-11 (6-amino-11,12-dihydro-11-(4-hydroxy-3,5-dimethoxyphenyl)benzo[c]phenanthridine) and BP-D7 (6-amino-11-(3,4,5-trimethoxyphenyl)benzo[c]phenanthridine) in vitro through incubation with human hepatic microsomes and marker substrates. For these studies the cytochrome P-450 isoenzymes and corresponding marker substrates recommended by the EMEA (The European Agency for the Evaluation of Medicinal Products) were chosen. In detail these selective substrates were caffeine (CYP1A2), coumarin (CYP2A6), tolbutamide (CYP2C9), S-(+)-mephenytoin (CYP2C19), dextromethorphane (CYP2D6), chlorzoxazone (CYP2E1) and testosterone (CYP3A4). Incubations with each substrate were carried out without a possible inhibitor and in the presence of a benzo[c]phenanthridine or a selective inhibitor at varying concentrations. Marker activities were determined by HPLC (high performance liquid chromatography). For the isoenzymes showing more than 50% inhibition by the addition of 20 microM BP-11 or BP-D7 additional concentrations of substrate and inhibitor were tested for a characterization of the inhibition. The studies showed a moderate risk for BP-11 for interactions with the cytochrome P-450 isoenzymes CYP1A2, CYP2C9, CYP2D6 and CYP3A4. BP-D7, the compound with the highest cytotstatic efficacy, showed only a moderate risk for interactions with drugs, also metabolized by CYP3A4.
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Affiliation(s)
- Inga Zebothsen
- Pharmaceutical Institute, Department of Pharmaceutical Chemistry, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76, D-24118 Kiel, Germany
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Xie WZ, Leibl M, Clark MR, Dohrmann P, Kunze T, Gieseler F. Activation of the coagulation system in cancerogenesis and metastasation. Biomed Pharmacother 2005; 59:70-5. [PMID: 15795099 DOI: 10.1016/j.biopha.2005.01.001] [Citation(s) in RCA: 4] [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] [Received: 09/10/2004] [Indexed: 11/30/2022] Open
Abstract
The activation of the coagulation system in cancer patients is a well-known phenomenon responsible for recurrent clinical problems. A number of fascinating molecular mechanisms have been recognized showing that the tumor not only activates the coagulation system, but vice versa, activated coagulation proteins are able to induce molecular effects in tumor cells. The molecular basis is the expression of defined membrane receptors by tumor cells that are activated, for example, by thrombin. As the liberation of thrombin from prothrombin is one of the key events in coagulation, it's impact upon biological processes, such as cancerogenesis and metastasation, seems to be a regular pathophysiological consequence. These perceptions are not only interesting for the comprehension of cancerogenesis, metastasation, and clinical phenomena, but they also have a high impact upon modern strategies of tumor therapy. Especially, the development of clinically useful coagulation inhibitors, such as modern low molecular weight heparins or melagatran, created the possibility of therapies that combine cell biological approaches with apoptosis-inducing principals such as chemotherapy. Several clinical studies that demonstrate the implication of these strategies have already been published recently. In this article the cell biological basics for these approaches are reviewed.
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Affiliation(s)
- W Z Xie
- Department of Internal Medicine, Section Hematology/Oncology, University of Kiel, Germany
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Abstract
Glutathione transferases (GSTs) have been shown to play an important role in multiple drug resistance in cancer chemotherapy. The inactivation of GST isoforms could lead to an enhanced activity of cytotoxic drugs. Thus, we have developed glutathione phosphono analogs [(S)-gamma-glutamyl-(2RS)-(+/-)-2-amino-(dialkoxyphosphinyl)-ac etylgl ycines], which were previously shown to be inhibitors of GSTP1-1. In the present study, the inhibition characteristics of these analogs, including isoenzyme specificities, type of inhibition, and determination of K(i) values, were determined. The inhibition of class alpha GSTs was competitive towards GSH. A mixed-type, non-competitive inhibition of class mu and pi GSTs was observed. The K(i) values varied between 880 +/- 210 and 0.45 +/- 0.1 microM. The inhibitors were most effective towards class mu GSTs. In order to investigate the potential use of these GST inhibitors in intact cellular systems, two additional approaches were examined. Firstly, the metabolic stability was tested with purified gamma-glutamyl transpeptidase and cell homogenates as well as during incubation of cell lines. No appreciable degradation was observed in any of the tested systems. Secondly, to facilitate cellular uptake, three derivatives were synthesized in which the glycine carboxylic group was esterified. Uptake and a possible intracellular cleavage to the corresponding free acids were monitored by HPLC analysis. The esters were effectively transported into HT29 (colon cancer) and EPG85-257P (gastric cancer) cells, respectively, and readily converted into the more active free acids. In conclusion, the tested inhibitors may be regarded as model compounds for the development of modulating agents in cancer chemotherapy.
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Affiliation(s)
- T Kunze
- Pharmazeutisches Institut, Christian-Albrechts-Universität, D-24118, Kiel, Germany.
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Asteroth A, Kunze T, Frings J, Moller K, Drescher J. Model based classification of cardiovascular response patterns. J Gravit Physiol 1999; 6:P41-2. [PMID: 11543020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
A comprehensive analysis of cardiovascular control (CVC) patterns with multiple subjects is presented. It became feasible by recent methodological advances. Simple computer models were generated automatically, reproducing only factors of the true model that are relevant to the focus if investigation. These models--named aspect-models--could in turn be used in model individualization, thus reducing the necessary computational amount. The achieved speedup by a factor of more than three thousand and the high numerical stability of the resulting method allows the unsupervised identification of a large body of experimental data. The analysis of tilt table experiments of 18 subjects revealed a remarkable variety of reaction patterns. Closer examination yielded different classes of subjects. Two main groups corresponding to basic types of CVC were observed. Three outliers could be assigned to the specific situation of some subjects.
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Affiliation(s)
- A Asteroth
- Bonn University, Department of Computer Science I, Germany.
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Abstract
Six cytosolic GSTs from porcine liver were purified by a combination of glutathione affinity chromatography and ion-exchange HPLC. The isoenzymes were characterized by SDS-PAGE, gel filtration, isoelectric focusing, immunoblotting analysis and determination of substrate specificities and inhibition characteristics. The purified GSTs belong to the alpha and mu classes, respectively. No class pi isoenzyme was isolated or detected. The class alpha GST pA1-1* exists as a homodimer (M(r) = 25.3 kDa), whereas GST pA2-3* consists of two subunits with different M(r) values (27.0 and 25.3 kDa). The estimated pI values were 9.5 and 8.8, respectively. Furthermore, four class mu porcine GSTs, pM1-1*, pM1-2*, pM3-?* and pM4-?*, were isolated. The isoenzyme pM1-1* possesses a relative molecular mass of 27.2 kDa and a pI value of 6.2. Additional pM1 isoenzymes hybridize with the subunit pM2* (M(r) = 25.2) to furnish a heterodimer, which shows a pI value of 5.8. The other class mu isoenzymes are heterodimers with pI values of 5.45 and 5.05. Substrate specificities and inhibition characteristics correlate very well with those of the corresponding human isoenzymes. The results are discussed with regard to the usefulness of porcine GSTs as an in vitro testing model.
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Affiliation(s)
- T Kunze
- Pharmazeutisches Institut, Christian Albrechts Universität, Kiel, Germany.
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Abstract
Phosphono-analogues of glutathione containing the O = P(OR)2 moiety in place of the cysteinyl residue CH2SH 1a-1d were prepared by solution phase peptide synthesis. Benzyl, benzyloxy-carbonyl, and tert-butyl protecting groups were used to mask the individual amino acid functional groups. The formation of peptide bonds was achieved by the usual peptide synthesis via activation of carboxylic functions with cyclohexylcarbodiimide and subsequent reaction with free amino groups. The thus obtained, fully-protected peptides were each purified by normal phase column chromatography. Deprotection was accomplished by hydrogenolysis and by treatment with HBr/acetic acid yielding the desired phosphonic acid diester 1a-1d. The inhibition of the glutathione conjugation of 1-chloro-2,4-dinitrobenzene by human placental glutathione S-transferase was studied by determining the IC50 values of the new glutathione analogues. The IC50 values were 291 microM, 139 microM, 64 microM, and 21 microM for the dimethyl, diethyl, diisopropyl, and di-n-butyl esters, respectively. The results clearly show that the formal substitution of the glutathione thiol function by phosphonic acid esters leads to a new class of glutathione S-transferase inhibitors. Further investigations directed at the question of whether or not these glutathione analogues are suitable for a modulation in chemotherapy are in progress.
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Affiliation(s)
- T Kunze
- Pharmazeutisches Institut, Christian-Albrechts-Universität, Kiel, Germany
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Abstract
1. The enzymic C-oxygenation of N,N'-diphenylguanidine (DPG) to N-(4-hydroxyphenyl)-N'-phenylguanidine (4HPG) and the N-oxygenation of N,N'-bis-(pentafluorophenyl)-guanidine (BPG) to N"-hydroxy-N,N"-bis-(pentafluorophenyl)-guanidine (HBPG) is reported. 2. The metabolites were identified by t.l.c. and mass spectral analysis using synthetic reference compounds. 3. Rat and rabbit liver homogenates (9000 g supernatant and microsomes) were used as enzyme source. 4. The enzymic oxygenations were both O2 and NADPH dependent. NADPH could not be replaced by hydrogen peroxide. 5. 15N-n.m.r. spectroscopy was used to elucidate structure and tautomerism of BPG and HBPG.
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Affiliation(s)
- B Clement
- Pharmazeutisches Institut, Christian-Albrechts-Universität Kiel, Germany
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Abstract
During investigations on the N-oxygenation of adenine (1) the enzymatic formation of adenine 1-N-oxide 3 was demonstrated for the first time. The identity of this metabolite was confirmed by its chromatographic behaviour and UV-spectrum recorded after HPLC separation. Adenine 1-N-oxide (3) and similar oxygenated derivatives of adenine were synthesized as reference substances. The enzymatic formation of 3 exhibits the typical characteristics of a reaction catalysed by microsomal mono-oxygenases. In induction experiments, an increase in the rate of formation of 3 after pretreatment with phenobarbital was observed. A participation of those isoenzymes of the cytochrome P-450 enzyme system which can be induced by phenobarbital is assumed.
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Affiliation(s)
- B Clement
- Pharmazeutisches Institut, Christian Albrechts Universität Kiel, F.R.G
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Abstract
The genotoxic and mutagenic compound 6-N-hydroxylaminopurine (HAP) can be detoxified in vitro by enzymatic N-reduction to adenine. This reaction is catalysed by both rat and rabbit liver cytosolic fractions. The formation of adenine was monitored using HPLC. Subcellular distribution of the activity, kinetic parameters and the influence of various cofactors and inhibitors were determined. The N-reduction required NADH or hypoxanthine or xanthine and was strongly inhibited by allopurinol. These observations suggested that the N-reductase activity is due to xanthine oxidase (EC 1.2.3.2). Moreover, the involvement of xanthine oxidase is supported by the observation that purified cow milk xanthine oxidase also catalysed this reaction. The N-reduction of HAP was inhibited only weakly by oxygen. In addition, the formation of adenine is catalysed by either the oxidase or dehydrogenase form of xanthine oxidase. Thus, this reaction should be significant for the in vivo detoxification of HAP.
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Affiliation(s)
- B Clement
- Pharmazeutisches Institut, Christian-Albrechts Universität, Kiel, Federal Republic of Germany
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Abstract
The enzymatic N-hydroxylation of the purine base adenine to the genotoxic and mutagenic compound 6-N-hydroxylaminopurine is reported for the first time. Adenine was N-oxygenated in vitro by aerobic incubations with 3-methylcholanthrene or isosafrole induced microsomal fractions of rat liver homogenates and NADPH. The formation of 6-N-hydroxylaminopurine in the incubation mixtures under widely differing conditions was assayed using newly-developed, high-performance liquid- and thin-layer chromatographic methods. Optimal reaction conditions and kinetic parameters were determined. Neither superoxide anion nor hydrogen peroxide was directly involved in the N-hydroxylation reaction. Oxidases like xanthine oxidase and peroxidase (in the presence of hydrogen peroxide) did not catalyse this N-hydroxylation. The involvement of cytochrome P-450 isoenzymes in this reaction is supported by the observation that the N-hydroxylation is only observed after pretreatment of the rats with 3-methylcholanthrene or isosafrole. Other inducers (phenobarbital, ethanol, 5-pregnen-3 beta ol-20-one-16 alpha-carbonitrile) were without effect. This is the first example of the microsomal transformation of an endogenous substance to a toxic derivative by usually foreign substances (xenobiotics) metabolizing cytochrome P-450 isoenzymes. The significance for the in vivo situation is discussed on the basis of the data obtained in this study.
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Affiliation(s)
- B Clement
- Institut für Pharmazeutische Chemie, Philipps-Universität, Marburg, Federal Republic of Germany
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