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Ilicic K, Dollinger G, Dombrowsky A, Greubel C, Girst S, Sammer M, Siebenwirth C, Schmid E, Friedrich T, Kundrát P, Friedland W, Scholz M, Combs SE, Schmid TE, Reindl J. Enhanced RBE of Particle Radiation Depends on Beam Size in the Micrometer Range. Radiat Res 2024; 201:140-149. [PMID: 38214379 DOI: 10.1667/rade-23-00217.1] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/01/2023] [Indexed: 01/13/2024]
Abstract
High-linear energy transfer (LET) radiation, such as heavy ions is associated with a higher relative biological effectiveness (RBE) than low-LET radiation, such as photons. Irradiation with low- and high-LET particles differ in the interaction with the cellular matter and therefore in the spatial dose distribution. When a single high-LET particle interacts with matter, it results in doses of up to thousands of gray (Gy) locally concentrated around the ion trajectory, whereas the mean dose averaged over the target, such as a cell nucleus is only in the range of a Gy. DNA damage therefore accumulates in this small volume. In contrast, up to hundreds of low-LET particle hits are required to achieve the same mean dose, resulting in a quasi-homogeneous damage distribution throughout the cell nucleus. In this study, we investigated the dependence of RBE from different spatial dose depositions using different focused beam spot sizes of proton radiation with respect to the induction of chromosome aberrations and clonogenic cell survival. Human-hamster hybrid (AL) as well as Chinese hamster ovary cells (CHO-K1) were irradiated with focused low LET protons of 20 MeV (LET = 2.6 keV/µm) beam energy with a mean dose of 1.7 Gy in a quadratic matrix pattern with point spacing of 5.4 × 5.4 µm2 and 117 protons per matrix point at the ion microbeam SNAKE using different beam spot sizes between 0.8 µm and 2.8 µm (full width at half maximum). The dose-response curves of X-ray reference radiation were used to determine the RBE after a 1.7 Gy dose of radiation. The RBE for the induction of dicentric chromosomes and cell inactivation was increased after irradiation with the smallest beam spot diameter (0.8 µm for chromosome aberration experiments and 1.0 µm for cell survival experiments) compared to homogeneous proton radiation but was still below the RBE of a corresponding high LET single ion hit. By increasing the spot size to 1.6-1.8 µm, the RBE decreased but was still higher than for homogeneously distributed protons. By further increasing the spot size to 2.7-2.8 µm, the RBE was no longer different from the homogeneous radiation. Our experiments demonstrate that varying spot size of low-LET radiation gradually modifies the RBE. This underlines that a substantial fraction of enhanced RBE originates from inhomogeneous energy concentrations on the µm scale (mean intertrack distances of low-LET particles below 0.1 µm) and quantifies the link between such energy concentration and RBE. The missing fraction of RBE enhancement when comparing with high-LET ions is attributed to the high inner track energy deposition on the nanometer scale. The results are compared with model results of PARTRAC and LEM for chromosomal aberration and cell survival, respectively, which suggest mechanistic interpretations of the observed radiation effects.
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Affiliation(s)
- K Ilicic
- Institute of Radiation Medicine (IRM), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Department of Radiation Oncology, School of Medicine, Technische Universität München, Germany
| | - G Dollinger
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
| | - A Dombrowsky
- Institute of Radiation Medicine (IRM), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Department of Radiation Oncology, School of Medicine, Technische Universität München, Germany
| | - C Greubel
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
| | - S Girst
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
| | - M Sammer
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
| | - C Siebenwirth
- Department of Radiation Oncology, School of Medicine, Technische Universität München, Germany
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
| | - E Schmid
- Department for Anatomy and Cell Biology, Ludwig-Maximilians Universität München, Germany
| | - T Friedrich
- GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - P Kundrát
- GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - W Friedland
- Institute of Radiation Medicine (IRM), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - M Scholz
- GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - S E Combs
- Institute of Radiation Medicine (IRM), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Department of Radiation Oncology, School of Medicine, Technische Universität München, Germany
| | - T E Schmid
- Institute of Radiation Medicine (IRM), Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Department of Radiation Oncology, School of Medicine, Technische Universität München, Germany
| | - J Reindl
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr München, Neubiberg, Germany
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Friedrich T, Pfuhl T, Scholz M. Spectral composition of secondary electrons based on the Kiefer-Straaten ion track structure model. Phys Med Biol 2024; 69:025013. [PMID: 38118162 DOI: 10.1088/1361-6560/ad1765] [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: 06/06/2023] [Accepted: 12/20/2023] [Indexed: 12/22/2023]
Abstract
The major part of energy deposition of ionizing radiation is caused by secondary electrons, independent of the primary radiation type. However, their spatial concentration and their spectral properties strongly depend on the primary radiation type and finally determine the pattern of molecular damage e.g. to biological targets as the DNA, and thus the final effect of the radiation exposure. To describe the physical and to predict the biological consequences of charged ion irradiation, amorphous track structure approaches have proven to be pragmatic and helpful. There, the local dose deposition in the ion track is equated by considering the emission and slowing down of the secondary electrons from the primary particle track. In the present work we exploit the model of Kiefer and Straaten and derive the spectral composition of secondary electrons as function of the distance to the track center. The spectral composition indicates differences to spectra of low linear energy transfer (LET) photon radiation, which we confirm by a comparison with Monte Carlo studies. We demonstrate that the amorphous track structure approach provides a simple tool for evaluating the spectral electron properties within the track structure. Predictions of the LET of electrons across the track structure as well as the electronic dose build-up effect are derived. Implications for biological effects and corresponding predicting models based on amorphous track structure are discussed.
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Affiliation(s)
- T Friedrich
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, D-64291 Darmstadt, Germany
| | - T Pfuhl
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, D-64291 Darmstadt, Germany
| | - M Scholz
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, D-64291 Darmstadt, Germany
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3
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Friedrich T, Stengel A. Current state of phoenixin-the implications of the pleiotropic peptide in stress and its potential as a therapeutic target. Front Pharmacol 2023; 14:1076800. [PMID: 36860304 PMCID: PMC9968724 DOI: 10.3389/fphar.2023.1076800] [Citation(s) in RCA: 1] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/04/2023] [Indexed: 02/15/2023] Open
Abstract
Phoenixin is a pleiotropic peptide, whose known functions have broadened significantly over the last decade. Initially first described as a reproductive peptide in 2013, phoenixin is now recognized as being implicated in hypertension, neuroinflammation, pruritus, food intake, anxiety as well as stress. Due to its wide field of involvement, an interaction with physiological as well as psychological control loops has been speculated. It has shown to be both able to actively reduce anxiety as well as being influenced by external stressors. Initial rodent models have shown that central administration of phoenixin alters the behavior of the subjects when confronted with stress-inducing situations, proposing an interaction with the perception and processing of stress and anxiety. Although the research on phoenixin is still in its infancy, there are several promising insights into its functionality, which might prove to be of value in the pharmacological treatment of several psychiatric and psychosomatic illnesses such as anorexia nervosa, post-traumatic stress disorder as well as the increasingly prevalent stress-related illnesses of burnout and depression. In this review, we aim to provide an overview of the current state of knowledge of phoenixin, its interactions with physiological processes as well as focus on the recent developments in stress response and the possible novel treatment options this might entail.
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Affiliation(s)
- T. Friedrich
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - A. Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité—Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany,Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany,*Correspondence: A. Stengel,
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Oppermann S, Seng K, Shweich L, Friedrich T. The gene order in the nuo-operon is not essential for the assembly of E. coli complex I. Biochim Biophys Acta Bioenerg 2022; 1863:148592. [PMID: 35863511 DOI: 10.1016/j.bbabio.2022.148592] [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] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/25/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Energy-converting NADH: ubiquinone oxidoreductase, respiratory complex I, plays an important role in cellular energy metabolism. Bacterial complex I is generally composed of 14 different subunits, seven of which are membranous and the other seven are globular proteins. They are encoded by the nuo-operon, whose gene order is strictly conserved in bacteria. The operon starts with nuoA encoding a membranous subunit followed by genes encoding globular subunits. To test the idea that NuoA acts as a seed to initiate the assembly of the complex in the membrane, we generated mutants that either lacked nuoA or contain nuoA at a different position within the operon. To enable the detection of putative assembly intermediates, the globular subunit NuoF and the membranous subunit NuoM were individually decorated with the fluorescent protein mCherry. Deletion of nuoA led to the assembly of an inactive complex in the membrane containing NuoF and NuoM. Re-arrangement of nuoA within the nuo-operon led to a slightly diminished amount of complex I in the membrane that was fully active. Thus, nuoA but not its distinct position in the operon is required for the assembly of E. coli complex I. Furthermore, we detected a previously unknown assembly intermediate in the membrane containing NuoM that is present in greater amounts than complex I.
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Affiliation(s)
- S Oppermann
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - K Seng
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - L Shweich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - T Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
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Wegner F, Schwenke H, von Gladiß A, Behrends A, Friedrich T, Lüdtke-Buzug K, Neumann A, Barkhausen J, Buzug MT, Bakenecker CA. Steuerung und Visualisierung eines endovaskulären Mikroroboters mittels Magnetic Particle Imaging. ROFO-FORTSCHR RONTG 2022. [DOI: 10.1055/s-0042-1749779] [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: 11/07/2022]
Affiliation(s)
- F Wegner
- UKSH, Campus Lübeck, Klinik f. Radiologie u. Nuklearmedizin, Lübeck
| | - H Schwenke
- Institut für Neuroradiologie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck
| | - A von Gladiß
- Institut für Computervisualistik, Universität Koblenz-Landau, Koblenz
| | - A Behrends
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
| | - T Friedrich
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
| | | | | | - J Barkhausen
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck
| | - M T Buzug
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
| | - C A Bakenecker
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
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Grzyska U, Friedrich T, Haegele J, Buzug MT, Barkhausen J, Wegner F. Sicherheit eines neuen Stentdesigns hinsichtlich der Erwärmung in Magnetic Particle Imaging und Magnetresonanztomographie. ROFO-FORTSCHR RONTG 2022. [DOI: 10.1055/s-0042-1749780] [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: 11/05/2022]
Affiliation(s)
- U Grzyska
- UKSH – Campus Lübeck, Klinik f. Radiologie u. Nuklearmedizin, Lübeck
| | - T Friedrich
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
| | - J Haegele
- Zentrum für Radiologie und Nuklearmedizin Rheinland, Dormagen
| | - M T Buzug
- Fraunhofer Einrichtung für Individualisierte und Zell-basierte Medizintechnik, Lübeck
| | - J Barkhausen
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck
| | - F Wegner
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck
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Hartel C, Nasonova E, Ritter S, Friedrich T. Alpha-Particle Exposure Induces Mainly Unstable Complex Chromosome Aberrations which do not Contribute to Radiation-Associated Cytogenetic Risk. Radiat Res 2021; 196:561-573. [PMID: 34411274 DOI: 10.1667/rade-21-00116.1] [Citation(s) in RCA: 4] [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] [Received: 06/04/2021] [Accepted: 08/06/2021] [Indexed: 11/03/2022]
Abstract
The mechanism underlying the carcinogenic potential of α radiation is not fully understood, considering that cell inactivation (e.g., mitotic cell death) as a main consequence of exposure efficiently counteracts the spreading of heritable DNA damage. The aim of this study is to improve our understanding of the effectiveness of α particles in inducing different types of chromosomal aberrations, to determine the respective values of the relative biological effectiveness (RBE) and to interpret the results with respect to exposure risk. Human peripheral blood lymphocytes (PBLs) from a single donor were exposed ex vivo to doses of 0-6 Gy X rays or 0-2 Gy α particles. Cells were harvested at two different times after irradiation to account for the mitotic delay of heavily damaged cells, which is known to occur after exposure to high-LET radiation (including α particles). Analysis of the kinetics of cells reaching first or second (and higher) mitosis after irradiation and aberration data obtained by the multiplex fluorescence in situ hybridization (mFISH) technique are used to determine of the cytogenetic risk, i.e., the probability for transmissible aberrations in surviving lymphocytes. The analysis shows that the cytogenetic risk after α exposure is lower than after X rays. This indicates that the actually observed higher carcinogenic effect of α radiation is likely to stem from small scale mutations that are induced effectively by high-LET radiation but cannot be resolved by mFISH analysis.
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Affiliation(s)
- C Hartel
- GSI Helmholtz Centre for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - E Nasonova
- GSI Helmholtz Centre for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany.,Joint Institute for Nuclear Research, Laboratory of Radiation Biology, Dubna, Russia
| | - S Ritter
- GSI Helmholtz Centre for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
| | - T Friedrich
- GSI Helmholtz Centre for Heavy Ion Research, Department of Biophysics, Darmstadt, Germany
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Schalla MA, Goebel-Stengel M, Friedrich T, Kühne SG, Kobelt P, Rose M, Stengel A. Restraint stress affects circulating NUCB2/nesfatin-1 and phoenixin levels in male rats. Psychoneuroendocrinology 2020; 122:104906. [PMID: 33059202 DOI: 10.1016/j.psyneuen.2020.104906] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/27/2022]
Abstract
The two peptides phoenixin and nesfatin-1 are colocalized in hypothalamic nuclei involved in the mediation of food intake and behavior. Phoenixin stimulates food intake and is anxiolytic, while nesfatin-1 is an anorexigenic peptide shown to increase anxiety and anhedonia. Interestingly, central activation of both peptides can be stimulated by restraint stress giving rise to a role in the mediation of stress. Thus, the aim of the study was to test whether also peripheral circulating levels of NUCB2/nesfatin-1 and phoenixin are altered by restraint stress. Male ad libitum fed Sprague Dawley rats equipped with a chronic intravenous catheter were subjected to restraint stress and plasma levels of NUCB2/nesfatin-1, phoenixin and cortisol were measured over a period of 240 min and compared to levels of freely moving rats. Peripheral cortisol levels were significantly increased in restrained rats at 30, 60, 120 and 240 min compared to controls (p < 0.05). In contrast, restraint stress decreased plasma phoenixin levels at 15 min compared to unstressed conditions (0.8-fold, p < 0.05). Circulating NUCB2/nesfatin-1 levels were increased only at 240 min in restrained rats compared to those in unstressed controls (1.3-fold, p < 0.05). In addition, circulating NUCB2/nesfatin-1 levels correlated positively with phoenixin levels (r = 0.378, p < 0.001), while neither phoenixin nor nesfatin-1 were associated with cortisol levels (r = 0.0275, and r=-0.143, p> 0.05). These data suggest that both peptides, NUCB2/nesfatin-1 and phoenixin, are affected by restraint stress, although less pronounced than circulating cortisol.
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Affiliation(s)
- M A Schalla
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - M Goebel-Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; Department of Internal Medicine, HELIOS Kliniken GmbH, Rottweil, Germany; Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany
| | - T Friedrich
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - S G Kühne
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - P Kobelt
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - M Rose
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, USA
| | - A Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
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Schalla MA, Kühne SG, Friedrich T, Kobelt P, Goebel-Stengel M, Long M, Rivalan M, Winter Y, Mori M, Rose M, Stengel A. Central blockage of nesfatin-1 has anxiolytic effects but does not prevent corticotropin-releasing factor-induced anxiety in male rats. Biochem Biophys Res Commun 2020; 529:773-777. [DOI: 10.1016/j.bbrc.2020.05.163] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/21/2020] [Indexed: 11/24/2022]
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Friedrich T, Schalla MA, Lommel R, Goebel-Stengel M, Kobelt P, Rose M, Stengel A. Restraint stress increases the expression of phoenixin immunoreactivity in rat brain nuclei. Brain Res 2020; 1743:146904. [PMID: 32474019 DOI: 10.1016/j.brainres.2020.146904] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/01/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022]
Abstract
Phoenixin is a recently discovered peptide, which has been associated with reproduction, anxiety and food intake. Based on a considerable co-localization it has been linked to nesfatin-1, with a possible antagonistic mode of action. Since nesfatin-1 is known to play a role in anxiety and the response to stress, this study aims to investigate the effects of a well-established psychological stress model, restraint stress, on phoenixin-expressing brain nuclei and phoenixin expression in rats. Male Sprague-Dawley rats were subjected to restraint stress (n = 8) or left undisturbed (control, n = 6) and the brains processed for c-Fos- and phoenixin immunohistochemistry. The number of c-Fos expressing cells was counted and phoenixin expression assessed semiquantitatively. Restraint stress significantly increased c-Fos expression in the dorsal motor nucleus of vagus nerve (DMN, 52-fold, p < 0.001), raphe pallidus (RPa, 15-fold, p < 0.001), medial part of the nucleus of the solitary tract (mNTS, 16-fold, p < 0.001), central amygdaloid nucleus, medial division (CeM, 9-fold, p = 0.01), supraoptic nucleus (SON, 9-fold, p < 0.001) and the arcuate nucleus (Arc, 2.5-fold, p < 0.03) compared to control animals. Also phoenixin expression significantly increased in the DMN (17-fold, p < 0.001), RPa (2-fold, p < 0.001) and mNTS (1.6-fold, p < 0.001) with positive correlations between c-Fos and phoenixin (r = 0.74-0.85; p < 0.01) in these nuclei. This pattern of activation suggests an involvement of phoenixin in response to restraint stress. Whether phoenixin mediates stress effects or is activated in a counterbalancing fashion will have to be further investigated.
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Affiliation(s)
- T Friedrich
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - M A Schalla
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - R Lommel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - M Goebel-Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; Department of Internal Medicine, Helios Kliniken GmbH, Rottweil, Germany; Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany
| | - P Kobelt
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - M Rose
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - A Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charite - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
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Wilkening S, Schmitt FJ, Lenz O, Zebger I, Horch M, Friedrich T. Discriminating changes in intracellular NADH/NAD + levels due to anoxicity and H 2 supply in R. eutropha cells using the Frex fluorescence sensor. Biochim Biophys Acta Bioenerg 2019; 1860:148062. [PMID: 31419395 DOI: 10.1016/j.bbabio.2019.148062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/23/2019] [Accepted: 08/10/2019] [Indexed: 12/19/2022]
Abstract
The hydrogen-oxidizing "Knallgas" bacterium Ralstonia eutropha can thrive in aerobic and anaerobic environments and readily switches between heterotrophic and autotrophic metabolism, making it an attractive host for biotechnological applications including the sustainable H2-driven production of hydrocarbons. The soluble hydrogenase (SH), one out of four different [NiFe]-hydrogenases in R. eutropha, mediates H2 oxidation even in the presence of O2, thus providing an ideal model system for biological hydrogen production and utilization. The SH reversibly couples H2 oxidation with the reduction of NAD+ to NADH, thereby enabling the sustainable regeneration of this biotechnologically important nicotinamide cofactor. Thus, understanding the interaction of the SH with the cellular NADH/NAD+ pool is of high interest. Here, we applied the fluorescent biosensor Frex to measure changes in cytoplasmic [NADH] in R. eutropha cells under different gas supply conditions. The results show that Frex is well-suited to distinguish SH-mediated changes in the cytoplasmic redox status from effects of general anaerobiosis of the respiratory chain. Upon H2 supply, the Frex reporter reveals a robust fluorescence response and allows for monitoring rapid changes in cellular [NADH]. Compared to the Peredox fluorescence reporter, Frex displays a diminished NADH affinity, which prevents the saturation of the sensor under typical bacterial [NADH] levels. Thus, Frex is a valuable reporter for on-line monitoring of the [NADH]/[NAD+] redox state in living cells of R. eutropha and other proteobacteria. Based on these results, strategies for a rational optimization of fluorescent NADH sensors are discussed.
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Affiliation(s)
- S Wilkening
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - F-J Schmitt
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - O Lenz
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - I Zebger
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - M Horch
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany; Department of Chemistry and York Biomedical Research Institute, University of York, YO10 5DD, United Kingdom
| | - T Friedrich
- Technische Universität Berlin, Institut für Chemie PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany.
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Roch PJ, Friedrich T, Bönninghoff R, Dinter D, Rickert A. [Laparoscopic resection of a giant colon diverticulum : Case report and review of the literature]. Chirurg 2018; 88:682-686. [PMID: 28374053 DOI: 10.1007/s00104-017-0412-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Giant diverticula are rare complications of diverticular disease. Current opinion regards operative therapy as the method of choice for the treatment of symptomatic giant diverticula; however, there is neither consensus about the technique nor about the necessary extent of resection. Based on a non-systematic review of the literature, an overview of giant diverticula in terms of epidemiology, pathology and classification is given. The current case is considered with respect to appropriate diagnostic procedures and possible therapeutic options. CASE PRESENTATION An 80-year-old female patient presented to the emergency department with abdominal pain and dyspnea. A computed tomography scan showed a large gas-filled structure in the upper left abdomen adjacent to the left colon. A giant colonic diverticulum was suspected and laparoscopy was performed. Intraoperatively, the diagnosis of a giant colon diverticulum located at the splenic flexure was confirmed. An unremarkable diverticulosis only was found in the descending colon. The giant diverticulum was treated by an atypical colon wedge resection and the postoperative course was uneventful. DISCUSSION This case report describes a laparoscopic atypical colon wedge resection as treatment of a giant colon diverticulum. Only four laparoscopic bowel resections in terms of sigmoid resections or hemicolectomy with primary anastomosis have been reported. Minimally invasive surgery can be a valuable alternative to open procedures. In the current case a laparoscopic atypical colon wedge resection was safely performed. This option might be considered as an alternative to extended resections of giant diverticula. Localization of the giant diverticulum and the simultaneous existence of diverticular disease are the main criteria for the decision between the different operative approaches.
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Affiliation(s)
- P J Roch
- Klinik für Allgemein-, Viszeral- und Transplantationschirurgie, Universitätsklinikums Heidelberg, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - T Friedrich
- Radiologische Abteilung des St. Josefskrankenhaus Heidelberg, St. Josefskrankenhaus Heidelberg, Landhausstraße 25, 69115, Heidelberg, Deutschland
| | - R Bönninghoff
- Chirurgische Abteilung des St. Josefskrankenhaus Heidelberg, St. Josefskrankenhaus Heidelberg, Landhausstraße 25, 69115, Heidelberg, Deutschland
| | - D Dinter
- Radiologie Schwetzingen, Bodelschwinghstr. 10, 68723, Schwetzingen, Deutschland
| | - A Rickert
- Chirurgische Abteilung des St. Josefskrankenhaus Heidelberg, St. Josefskrankenhaus Heidelberg, Landhausstraße 25, 69115, Heidelberg, Deutschland.
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Affiliation(s)
- A. Kassam
- School of Agriculture, Policy and Development, University of Reading, UK
| | - T. Friedrich
- Food and Agriculture Organization (FAO) of the United Nations, La Paz, Bolivia
| | - R. Derpsch
- International Consultant for Conservation Agriculture/No-till, Asunción, Paraguay
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Friedrich T, Bochmann A, Dinger J, Teichert S. Application of the pattern matching approach for EBSD calibration and orientation mapping, utilising dynamical EBSP simulations. Ultramicroscopy 2018; 184:44-51. [DOI: 10.1016/j.ultramic.2017.10.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/05/2017] [Accepted: 10/10/2017] [Indexed: 11/28/2022]
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Boscary J, Friedrich T, Greuner H, Schulmeyer W, Stadler R, Mendelevitch B, Junghanns P, Ehrke G. Summary of the production of the divertor target elements of Wendelstein 7-X. Fusion Engineering and Design 2017. [DOI: 10.1016/j.fusengdes.2017.03.084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Sokol O, Scifoni E, Tinganelli W, Kraft-Weyrather W, Wiedemann J, Maier A, Boscolo D, Friedrich T, Brons S, Durante M, Krämer M. Oxygen beams for therapy: advanced biological treatment planning and experimental verification. Phys Med Biol 2017; 62:7798-7813. [PMID: 28841579 DOI: 10.1088/1361-6560/aa88a0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nowadays there is a rising interest towards exploiting new therapeutical beams beyond carbon ions and protons. In particular, [Formula: see text]O ions are being widely discussed due to their increased LET distribution. In this contribution, we report on the first experimental verification of biologically optimized treatment plans, accounting for different biological effects, generated with the TRiP98 planning system with [Formula: see text]O beams, performed at HIT and GSI. This implies the measurements of 3D profiles of absorbed dose as well as several biological measurements. The latter includes the measurements of relative biological effectiveness along the range of linear energy transfer values from ≈20 up to ≈750 keV μ [Formula: see text], oxygen enhancement ratio values and the verification of the kill-painting approach, to overcome hypoxia, with a phantom imitating an unevenly oxygenated target. With the present implementation, our treatment planning system is able to perform a comparative analysis of different ions, according to any given condition of the target. For the particular cases of low target oxygenation, [Formula: see text]O ions demonstrate a higher peak-to-entrance dose ratio for the same cell killing in the target region compared to [Formula: see text]C ions. Based on this phenomenon, we performed a short computational analysis to reveal the potential range of treatment plans, where [Formula: see text]O can benefit over lighter modalities. It emerges that for more hypoxic target regions (partial oxygen pressure of ≈0.15% or lower) and relatively low doses (≈4 Gy or lower) the choice of [Formula: see text]O over [Formula: see text]C or [Formula: see text]He may be justified.
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Affiliation(s)
- O Sokol
- Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, D-64291 Darmstadt, Germany
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Hunter P, Delbaere M, O’Connell ME, Cammer A, Seaton JX, Friedrich T, Fick F. Did online publishers "get it right"? Using a naturalistic search strategy to review cognitive health promotion content on internet webpages. BMC Geriatr 2017; 17:125. [PMID: 28619010 PMCID: PMC5472889 DOI: 10.1186/s12877-017-0515-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 06/06/2017] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND One of the most common uses of the Internet is to search for health-related information. Although scientific evidence pertaining to cognitive health promotion has expanded rapidly in recent years, it is unclear how much of this information has been made available to Internet users. Thus, the purpose of our study was to assess the reliability and quality of information about cognitive health promotion encountered by typical Internet users. METHODS To generate a list of relevant search terms employed by Internet users, we entered seed search terms in Google Trends and recorded any terms consistently used in the prior 2 years. To further approximate the behaviour of typical Internet users, we entered each term in Google and sampled the first two relevant results. This search, completed in October 2014, resulted in a sample of 86 webpages, 48 of which had content related to cognitive health promotion. An interdisciplinary team rated the information reliability and quality of these webpages using a standardized measure. RESULTS We found that information reliability and quality were moderate, on average. Just one retrieved page mentioned best practice, national recommendations, or consensus guidelines by name. Commercial content (i.e., product promotion, advertising content, or non-commercial) was associated with differences in reliability and quality, with product promoter webpages having the lowest mean reliability and quality ratings. CONCLUSIONS As efforts to communicate the association between lifestyle and cognitive health continue to expand, we offer these results as a baseline assessment of the reliability and quality of cognitive health promotion on the Internet.
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Affiliation(s)
- P.V. Hunter
- St. Thomas More College, University of Saskatchewan, 1437 College Drive, Saskatoon, SK S7M 0W6 Canada
| | - M. Delbaere
- Edwards School of Business, University of Saskatchewan, 25 Campus Drive, Saskatoon, SK S7N 5A7 Canada
| | - M. E. O’Connell
- Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada
| | - A. Cammer
- College of Pharmacy and Nutrition, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9 Canada
| | - J. X. Seaton
- Interdisciplinary Studies, University of Saskatchewan, 176 Thorvaldson Building, 110 Science Place, Saskatoon, SK S7N 5C9 Canada
| | - T. Friedrich
- Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada
| | - F. Fick
- Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada
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Maksimov EG, Moldenhauer M, Shirshin EA, Parshina EA, Sluchanko NN, Klementiev KE, Tsoraev GV, Tavraz NN, Willoweit M, Schmitt FJ, Breitenbach J, Sandmann G, Paschenko VZ, Friedrich T, Rubin AB. A comparative study of three signaling forms of the orange carotenoid protein. Photosynth Res 2016; 130:389-401. [PMID: 27161566 DOI: 10.1007/s11120-016-0272-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/27/2016] [Indexed: 06/05/2023]
Abstract
Orange carotenoid protein (OCP) is a water-soluble photoactive protein responsible for a photoprotective mechanism of nonphotochemical quenching in cyanobacteria. Under blue-green illumination, OCP converts from the stable orange into the signaling red quenching form; however, the latter form could also be obtained by chemical activation with high concentrations of sodium thiocyanate (NaSCN) or point mutations. In this work, we show that a single replacement of tryptophan-288, normally involved in protein-chromophore interactions, by alanine, results in formation of a new protein form, hereinafter referred to as purple carotenoid protein (PCP). Comparison of resonance Raman spectra of the native photoactivated red form, chemically activated OCP, and PCP reveals that carotenoid conformation is sensitive to the structure of the C-domain, implicating that the chromophore retains some interactions with this part of the protein in the active red form. Combination of differential scanning fluorimetry and picosecond time-resolved fluorescence anisotropy measurements allowed us to compare the stability of different OCP forms and to estimate relative differences in protein rotation rates. These results were corroborated by hydrodynamic analysis of proteins by dynamic light scattering and analytical size-exclusion chromatography, indicating that the light-induced conversion of the protein is accompanied by a significant increase in its size. On the whole, our data support the idea that the red form of OCP is a molten globule-like protein in which, however, interactions between the carotenoid and the C-terminal domain are preserved.
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Affiliation(s)
- E G Maksimov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia.
| | - M Moldenhauer
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - E A Shirshin
- Department of Quantum Electronics, Faculty of Physics, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - E A Parshina
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - N N Sluchanko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - K E Klementiev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - G V Tsoraev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - N N Tavraz
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - M Willoweit
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - F-J Schmitt
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - J Breitenbach
- Institute for Molecular Biosciences, Johann Wolfgang Goethe University of Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - G Sandmann
- Institute for Molecular Biosciences, Johann Wolfgang Goethe University of Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - V Z Paschenko
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - T Friedrich
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - A B Rubin
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
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Sørensen B, Horsman M, Alsner J, Overgaard J, Durante M, Scholz M, Friedrich T, Bassler N. RBE for Carbon ions In Vivo for Tumor Control and Normal Tissue Damage. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)30006-8] [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: 11/29/2022]
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Bassler N, Grzanka L, Scholz M, Friedrich T, Durante M, Sharpe P, Palmans H, Sørensen B. Alanine as a Dose Verification Tool for Carbon Ion In-Vivo Irradiation. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)30014-7] [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: 11/15/2022]
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Friedrich T, Tommasino F, Herr L, Scholz U, Hufnagl A, Durante M, Scholz M. The relevance of DNA damage clustering on the nanometer and micrometer scale for the quantitative prediction of radiation effects. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)30195-5] [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: 11/24/2022]
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Tommasino F, Friedrich T, Scholz U, Taucher-Scholz G, Durante M, Scholz M. Application of the local effect model to predict DNA double-strand break rejoining after photon and high-LET irradiation. Radiat Prot Dosimetry 2015; 166:66-70. [PMID: 25877535 DOI: 10.1093/rpd/ncv164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the recent version of the local effect model (LEM), the biological effects of ionising radiation can be well described trough the consideration of DNA double-strand breaks (DSB) clustering at the micrometre scale. Assuming a giant-loop organisation for the chromatin higher-order structure, two classes of DSB are defined, namely isolated (iDSB) and clustered DSB (cDSB), according to whether exactly one or more than one DSB are induced in a loop, respectively. Here, a DSB kinetic rejoining model based on the LEM is applied to the description of two specific aspects of DSB rejoining, namely the dose dependence of the rejoining capacity after photon radiation and the residual damage observed at late times after ion irradiation. Based on the hypothesis that iDSB and cDSB can be associated to the fast and slow components of rejoining, the model is able to reproduce the experimental data, therefore supporting the relevance of micrometre scale clustering of damage for photon radiation as well as for high-LET radiation.
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Affiliation(s)
- F Tommasino
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - T Friedrich
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - U Scholz
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - G Taucher-Scholz
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - M Durante
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany Institut für Festkörperphysik, Technische Universität Darmstadt, Darmstadt, Germany
| | - M Scholz
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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Herr L, Friedrich T, Durante M, Scholz M. Sensitivity of the Giant LOop Binary LEsion (GLOBLE) cell survival model on parameters characterising dose rate effects. Radiat Prot Dosimetry 2015; 166:56-60. [PMID: 25883303 DOI: 10.1093/rpd/ncv150] [Citation(s) in RCA: 2] [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] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The sensitivity of the Giant LOop Binary LEsion model for cell survival probabilities after arbitrary photon irradiation schedules on its parameters is presented. Since these parameters are closely linked to observable features of cell repair, the modelled influence of the parameters on cell survival gives indications about the relation between cell line-specific repair characteristics and the radiation response. To visualise the general findings about the impact of parameter changes on cell survival probabilities, survival curves for an exemplary cell line are shown. Furthermore, the relative change in the effect of radiation after a change in parameter values is investigated over the range of doses and dose rates usually applied in cell survival experiments.
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Affiliation(s)
- L Herr
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung (GSI), Darmstadt, Germany
| | - T Friedrich
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung (GSI), Darmstadt, Germany
| | - M Durante
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung (GSI), Darmstadt, Germany Technische Universität Darmstadt, Institut für Festkörperphysik, Darmstadt, Germany
| | - M Scholz
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung (GSI), Darmstadt, Germany
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Abstract
A simulation approach for the calculation of the LET-dependent yield of double-strand breaks (DSB) is presented. The model considers DSB formed as two close-lying single-strand breaks (SSB), whose formation is mediated by both intra-track processes (single electrons) or at local doses larger than about 1000 Gy in particle tracks also by electron inter-track processes (two independent electron tracks). A Monte Carlo algorithm and an analytical formula for the DSB yield are presented. The approach predicts that the DSB yield is enhanced after charged particle irradiation of high LET compared with X-ray or gamma radiation. It is used as an inherent part of the local effect model, which is applied to estimate the relative biological effectiveness of high LET radiation.
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Affiliation(s)
- T Friedrich
- Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - M Durante
- Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany Institut für Festkörperphysik, Technische Universität Darmstadt, Darmstadt, Germany
| | - M Scholz
- Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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Steinsträter O, Scholz U, Friedrich T, Krämer M, Grün R, Durante M, Scholz M. Integration of a model-independent interface for RBE predictions in a treatment planning system for active particle beam scanning. Phys Med Biol 2015; 60:6811-31. [DOI: 10.1088/0031-9155/60/17/6811] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Lehmann R, Friedrich T, Krebiehl G, Sonntag D, Häring HU, Fritsche A, Hennige AM. Metabolic profiles during an oral glucose tolerance test in pregnant women with and without gestational diabetes. Exp Clin Endocrinol Diabetes 2015; 123:483-38. [PMID: 26171623 DOI: 10.1055/s-0035-1549887] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND/AIM Gestational diabetes (GDM) is a complex metabolic condition associated with hyperpglycemia that is diagnosed in an oral glucose tolerance test (OGTT) during pregnancy. For a deeper understanding of the pathology of the disease, further investigations during pregnancy are required, ideally under metabolic challenging conditions. METHODS We performed targeted metabolomics in a group of 24 well-matched women during an oral glucose tolerance test (OGTT). 231 plasma metabolites were profiled and compared to conventional clinical diagnostics. RESULTS A pattern of 8 metabolites differed between GDM and healthy controls as early as 30 min in an OGTT (AUC 0.977±0.008), and an increase in acylcarnitine C18:0, decreased concentrations of diacyl phosphatidylcholines (PC aa) C34:4, PC aa C36:4, PC aa C38:5, Lyso PC C20:4 and arachidonic acid were associated with insulin resistance. CONCLUSION Our data suggest an additional value of metabolite pattern in the diagnosis of GDM and describe altered pathways that might be subjected to a more precise diagnosis and individualized therapy.
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Affiliation(s)
- R Lehmann
- Division of Clinical Chemistry and Pathobiochemistry, University Hospital Tuebingen, Tuebingen, Germany
| | | | - G Krebiehl
- Biocrates Life Sciences, Innsbruck, Austria
| | - D Sonntag
- Biocrates Life Sciences, Innsbruck, Austria
| | - H-U Häring
- German Center for Diabetes Research (DZD), Tuebingen, Germany
| | - A Fritsche
- German Center for Diabetes Research (DZD), Tuebingen, Germany
| | - A M Hennige
- German Center for Diabetes Research (DZD), Tuebingen, Germany
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Friedrich T, Grimmer C, Woisetschläger D, Mayer N, Koncar M, Hacker V. Borhydride mit Ionic-Liquid-Kation als Wasserstoffspeicher - Rezyklierung des Speichermediums. CHEM-ING-TECH 2014. [DOI: 10.1002/cite.201450514] [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: 11/11/2022]
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Pena MJ, Lambers Heerspink HJ, Hellemons ME, Friedrich T, Dallmann G, Lajer M, Bakker SJL, Gansevoort RT, Rossing P, de Zeeuw D, Roscioni SS. Urine and plasma metabolites predict the development of diabetic nephropathy in individuals with Type 2 diabetes mellitus. Diabet Med 2014; 31:1138-47. [PMID: 24661264 DOI: 10.1111/dme.12447] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 01/09/2014] [Accepted: 03/17/2014] [Indexed: 12/26/2022]
Abstract
AIMS Early detection of individuals with Type 2 diabetes mellitus or hypertension at risk for micro- or macroalbuminuria may facilitate prevention and treatment of renal disease. We aimed to discover plasma and urine metabolites that predict the development of micro- or macroalbuminuria. METHODS Patients with Type 2 diabetes (n = 90) and hypertension (n = 150) were selected from the community-cohort 'Prevention of REnal and Vascular End-stage Disease' (PREVEND) and the Steno Diabetes Center for this case-control study. Cases transitioned in albuminuria stage (from normo- to microalbuminuria or micro- to macroalbuminuria). Controls, matched for age, gender, and baseline albuminuria stage, remained in normo- or microalbuminuria stage during follow-up. Median follow-up was 2.9 years. Metabolomics were performed on plasma and urine. The predictive performance of a metabolite for albuminuria transition was assessed by the integrated discrimination index. RESULTS In patients with Type 2 diabetes with normoalbuminuria, no metabolites discriminated cases from controls. In patients with Type 2 diabetes with microalbuminuria, plasma histidine was lower (fold change = 0.87, P = 0.02) and butenoylcarnitine was higher (fold change = 1.17, P = 0.007) in cases vs. controls. In urine, hexose, glutamine and tyrosine were lower in cases vs. controls (fold change = 0.20, P < 0.001; 0.32, P < 0.001; 0.51, P = 0.006, respectively). Adding the metabolites to a model of baseline albuminuria and estimated glomerular filtration rate metabolites improved risk prediction for macroalbuminuria transition (plasma integrated discrimination index = 0.28, P < 0.001; urine integrated discrimination index = 0.43, P < 0.001). These metabolites did not differ between hypertensive cases and controls without Type 2 diabetes. CONCLUSIONS Type 2 diabetes-specific plasma and urine metabolites were discovered that predict the development of macroalbuminuria beyond established renal risk markers. These results should be confirmed in a large, prospective cohort.
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Affiliation(s)
- M J Pena
- Department of Clinical Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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Grimmer C, Friedrich T, Woisetschläger D, Mayer N, Kalb R, Hacker V. Novel Borohydride-Based Ionic Liquids as Hydrogen Carrier. CHEM-ING-TECH 2014. [DOI: 10.1002/cite.201450539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Maksimov EG, Schmitt FJ, Tsoraev GV, Ryabova AV, Friedrich T, Paschenko VZ. Fluorescence quenching in the lichen Peltigera aphthosa due to desiccation. Plant Physiol Biochem 2014; 81:67-73. [PMID: 24485218 DOI: 10.1016/j.plaphy.2014.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Photoprotective mechanisms were studied on the tripartite lichen Peltigera aphthosa that exhibits external cephalodia. Using the methods of steady-state and time-resolved fluorescence microscopy, we studied the dynamics of the rehydration process in different parts of the lichen thalli. It was found that apical, medial and basal parts of the thallus are not only morphologically different, but also show completely different chlorophyll induction curves and other spectral characteristics. In dry state, significant contribution to the fluorescence spectrum of lichen gives a green fluorescence of hyphae forming the upper crust, which is rapidly and almost completely quenched during the rehydration process. Probably this is one of the protective mechanisms that reduce the amount of light reaching the PS II reaction centers in the dry state. In the process of rehydration, we observed an increase in the intensity of the chlorophyll fluorescence of the photobiont at 680 nm, with significant changes of the fluorescence lifetimes and the amplitude ratios of fast and slow components of fluorescence decay kinetics. While in dry state, chlorophyll fluorescence is strongly quenched (opposite to the fluorescence of the hyphae), and the fluorescence time constants recover to the typical decay times of active photosynthetic organisms during rehydration. The quantitative behavior of these changes differs largely between the apical, medial and basal parts of the thallus, probably due to the complex interactions of the fungus, algae and cyanobacteria.
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Affiliation(s)
- E G Maksimov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
| | - F-J Schmitt
- Institute of Chemistry, Biophysical Chemistry, Berlin Institute of Technology, 10623 Berlin, Germany
| | - G V Tsoraev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - A V Ryabova
- A.M.Prokhorov General Physics Institute RAS, 119991 Moscow, Russia
| | - T Friedrich
- Institute of Chemistry, Biophysical Chemistry, Berlin Institute of Technology, 10623 Berlin, Germany
| | - V Z Paschenko
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
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Weber ME, Clark PU, Kuhn G, Timmermann A, Sprenk D, Gladstone R, Zhang X, Lohmann G, Menviel L, Chikamoto MO, Friedrich T, Ohlwein C. Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature 2014; 510:134-8. [DOI: 10.1038/nature13397] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 04/16/2014] [Indexed: 11/09/2022]
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Maksimov EG, Schmitt FJ, Shirshin EA, Svirin MD, Elanskaya IV, Friedrich T, Fadeev VV, Paschenko VZ, Rubin AB. The time course of non-photochemical quenching in phycobilisomes of Synechocystis sp. PCC6803 as revealed by picosecond time-resolved fluorimetry. Biochim Biophys Acta 2014; 1837:1540-7. [PMID: 24463052 DOI: 10.1016/j.bbabio.2014.01.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/25/2013] [Accepted: 01/15/2014] [Indexed: 11/29/2022]
Abstract
As high-intensity solar radiation can lead to extensive damage of the photosynthetic apparatus, cyanobacteria have developed various protection mechanisms to reduce the effective excitation energy transfer (EET) from the antenna complexes to the reaction center. One of them is non-photochemical quenching (NPQ) of the phycobilisome (PB) fluorescence. In Synechocystis sp. PCC6803 this role is carried by the orange carotenoid protein (OCP), which reacts to high-intensity light by a series of conformational changes, enabling the binding of OCP to the PBs reducing the flow of energy into the photosystems. In this paper the mechanisms of energy migration in two mutant PB complexes of Synechocystis sp. were investigated and compared. The mutant CK is lacking phycocyanin in the PBs while the mutant ΔPSI/PSII does not contain both photosystems. Fluorescence decay spectra with picosecond time resolution were registered using a single photon counting technique. The studies were performed in a wide range of temperatures - from 4 to 300 K. The time course of NPQ and fluorescence recovery in darkness was studied at room temperature using both steady-state and time-resolved fluorescence measurements. The OCP induced NPQ has been shown to be due to EET from PB cores to the red form of OCP under photon flux densities up to 1000 μmolphotonsm⁻²s⁻¹. The gradual changes of the energy transfer rate from allophycocyanin to OCP were observed during the irradiation of the sample with blue light and consequent adaptation to darkness. This fact was interpreted as the revelation of intermolecular interaction between OCP and PB binding site. At low temperatures a significantly enhanced EET from allophycocyanin to terminal emitters has been shown, due to the decreased back transfer from terminal emitter to APC. The activation of OCP not only leads to fluorescence quenching, but also affects the rate constants of energy transfer as shown by model based analysis of the decay associated spectra. The results indicate that the ability of OCP to quench the fluorescence is strongly temperature dependent. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.
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Affiliation(s)
- E G Maksimov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
| | - F-J Schmitt
- Institute of Chemistry, Biophysical Chemistry, TU Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - E A Shirshin
- Department of Quantum Electronics, Faculty of Physics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - M D Svirin
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - I V Elanskaya
- Department of Genetics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - T Friedrich
- Institute of Chemistry, Biophysical Chemistry, TU Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - V V Fadeev
- Department of Quantum Electronics, Faculty of Physics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - V Z Paschenko
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - A B Rubin
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
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Tommasino F, Friedrich T, Scholz U, Taucher-Scholz G, Durante M, Scholz M. A DNA Double-Strand Break Kinetic Rejoining Model Based on the Local Effect Model. Radiat Res 2013; 180:524-38. [DOI: 10.1667/rr13389.1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Friedrich T, Grün R, Scholz U, Elsässer T, Durante M, Scholz M. Sensitivity analysis of the relative biological effectiveness predicted by the local effect model. Phys Med Biol 2013; 58:6827-49. [DOI: 10.1088/0031-9155/58/19/6827] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Eley J, Friedrich T, Homann K, Mahajan A, Durante M, Bert C, Howell R, Scholz M, Newhauser W. SU-E-T-278: Risk of Developing a Second Cancer in the Breast for Hodgkin Lymphoma Patients Receiving Carbon Ion Therapy Versus Proton Therapy. Med Phys 2013. [DOI: 10.1118/1.4814712] [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: 11/07/2022] Open
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Grün R, Friedrich T, Elsässer T, Krämer M, Zink K, Karger CP, Durante M, Engenhart-Cabillic R, Scholz M. Impact of enhancements in the local effect model (LEM) on the predicted RBE-weighted target dose distribution in carbon ion therapy. Phys Med Biol 2012; 57:7261-74. [PMID: 23075883 DOI: 10.1088/0031-9155/57/22/7261] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Biological optimization for treatment planning in carbon ion therapy is currently based on the first version of the local effect model (LEM I). Further developments implemented in the latest version (LEM IV) allowed to predict more accurately the Relative Biological Effectiveness (RBE) in-vitro. The main goal of this study is to compare the LEM IV against LEM I under treatment-like conditions for idealized target geometries. Therefore, physical dose distributions resulting from the biological optimization with LEM I were used to recalculate the RBE-weighted dose distribution based on LEM IV. Input parameters representing the clinical endpoints late toxicity in the central nervous system and the tumor control for chordoma were chosen to investigate the impact of changes on the predicted isoeffective dose levels. The recalculated RBE-weighted dose distributions show an increase within the target region, and the mean RBE-weighted dose values are dependent on the geometry and decrease with increasing target dimension. The differences between predictions of LEM IV and LEM I are less than 10% for typical tumor volumes treated in the pilot project at GSI. Median RBE-weighted doses predicted by LEM IV in the target region are consistent with clinically observed dose-response behavior as demonstrated by comparison to the 5-year local control curve for skull base chordoma.
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Affiliation(s)
- R Grün
- Department of Biophysics, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany.
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Boscary J, Peacock A, Friedrich T, Greuner H, Böswirth B, Tittes H, Schulmeyer W, Hurd F. Design improvement of the target elements of Wendelstein 7-X divertor. Fusion Engineering and Design 2012. [DOI: 10.1016/j.fusengdes.2012.03.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Schmitt FJ, Maksimov EG, Hätti P, Weißenborn J, Jeyasangar V, Razjivin AP, Paschenko VZ, Friedrich T, Renger G. Coupling of different isolated photosynthetic light harvesting complexes and CdSe/ZnS nanocrystals via Förster resonance energy transfer. Biochim Biophys Acta 2012; 1817:1461-70. [PMID: 22503663 DOI: 10.1016/j.bbabio.2012.03.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/28/2012] [Accepted: 03/28/2012] [Indexed: 11/18/2022]
Abstract
The present work describes results obtained on hybrid systems formed in aqueous buffer solution by self-assembly of different CdSe quantum dots (QDs) surrounded by a ZnS shell and functionalized by covering the surface with anionic and cationic groups and various isolated pigment-protein complexes from the light-harvesting antennae of photosynthetic organisms (light-harvesting complexes 1 and 2 (LH1 and LH2, respectively) from purple bacteria, phycobiliproteins (PBPs) from cyanobacteria and the rod-shaped PBP from the cyanobacterium Acaryochloris marina). Excitation energy transfer (EET) from QDs to PBP rods was found to take place with varying and highly temperature-dependent efficiencies of up to 90%. Experiments performed at room temperature on hybrid systems with different QDs show that no straightforward correlation exists between the efficiency of EET and the parameter J/(R(12)(6)) given by the theory of Förster resonance energy transfer (FRET), where J is the overlap integral of the normalized QD emission and PBP absorption and R(12) the distance between the transition dipole moments of donor and acceptor. The results show that the hybrid systems cannot be described as randomly orientated aggregates consisting of QDs and photosynthetic pigment-protein complexes. Specific structural parameters are inferred to play an essential role. The mode of binding and coupling seems to change with the size of QDs and with temperature. Efficient EET and fluorescence enhancement of the acceptor was observed at particular stoichiometric ratios between QDs and trimeric phycoerythrin (PE). At higher concentrations of PE, a quenching of its fluorescence is observed in the presence of QDs. This effect is explained by the existence of additional quenching channels in aggregates formed within hybrid systems. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- F-J Schmitt
- Institute of Chemistry, Biophysical Chemistry, Berlin Institute of Technology, Berlin, Germany.
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Gillmann C, Scholz M, Karger C, Greilich S, Ellerbrock M, Grün R, Friedrich T, Debus J, Jäkel O. 297 A TREATMENT PLANNING STUDY COMPARING DIFFERENT RADIOBIOLOGICAL MODELS FOR HEAVY ION THERAPY. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)70260-8] [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: 11/15/2022]
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Kassam A, Friedrich T, Shaxson F, Reeves T, Pretty J, De Moraes Sá J. Production Systems for Sustainable Intensification. ACTA ACUST UNITED AC 2011. [DOI: 10.14512/tatup.20.2.38] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
Tree reconstruction methods are often judged by their accuracy, measured by how close they get to the true tree. Yet, most reconstruction methods like maximum likelihood (ML) do not explicitly maximize this accuracy. To address this problem, we propose a Bayesian solution. Given tree samples, we propose finding the tree estimate that is closest on average to the samples. This "median" tree is known as the Bayes estimator (BE). The BE literally maximizes posterior expected accuracy, measured in terms of closeness (distance) to the true tree. We discuss a unified framework of BE trees, focusing especially on tree distances that are expressible as squared euclidean distances. Notable examples include Robinson-Foulds (RF) distance, quartet distance, and squared path difference. Using both simulated and real data, we show that BEs can be estimated in practice by hill-climbing. In our simulation, we find that BEs tend to be closer to the true tree, compared with ML and neighbor joining. In particular, the BE under squared path difference tends to perform well in terms of both path difference and RF distances.
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Affiliation(s)
- P M Huggins
- Lane Center for Computational Biology, Carnegie Mellon University, Mellon Institute Building, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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Friedrich T, Weyrather W, Elsässer T, Durante M, Scholz M. Accuracy of RBE: experimental and theoretical considerations. Radiat Environ Biophys 2010; 49:345-349. [PMID: 20556619 DOI: 10.1007/s00411-010-0298-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 05/21/2010] [Indexed: 05/29/2023]
Abstract
The concept of the relative biological effectiveness (RBE) is essential for treatment planning in carbon ion therapy and for understanding the biological effects of high-LET radiation. As this quantity depends on many factors, both its experimental determination and the assessment of its uncertainty are not trivial. For the limiting case of zero dose, where the RBE takes its maximum value RBE(alpha), we present in this article a simple empirical-based approach to estimate its uncertainty. A Gaussian error calculus is applied to equally take into account both uncertainties from experiments with high- and low-LET radiation. From a theoretical point of view, we then infer, using a simple Monte Carlo model, the distribution of RBE(alpha) values. This illustrates why the conventional error propagation approach is inappropriate in some cases. In these cases, likewise also the error estimates have to be obtained with a more sophisticated approach. Uncertainties of RBE, visualized by error bars, are of importance for treatment planning and also for setting up a precision goal for predicting biophysical models such as the local effect model.
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Affiliation(s)
- T Friedrich
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany.
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Dietz B, Friedrich T, Harney HL, Miski-Oglu M, Richter A, Schäfer F, Weidenmüller HA. Quantum chaotic scattering in microwave resonators. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 81:036205. [PMID: 20365830 DOI: 10.1103/physreve.81.036205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Indexed: 05/29/2023]
Abstract
In a frequency range where a microwave resonator simulates a chaotic quantum billiard, we have measured moduli and phases of reflection and transmission amplitudes in the regimes of both isolated and of weakly overlapping resonances and for resonators with and without time-reversal invariance. Statistical measures for S -matrix fluctuations were determined from the data and compared with extant and/or newly derived theoretical results obtained from the random-matrix approach to quantum chaotic scattering. The latter contained a small number of fit parameters. The large data sets taken made it possible to test the theoretical expressions with unprecedented accuracy. The theory is confirmed by both a goodness-of-fit-test and the agreement of predicted values for those statistical measures that were not used for the fits, with the data.
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Affiliation(s)
- B Dietz
- Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
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Bäcker A, Dietz B, Friedrich T, Miski-Oglu M, Richter A, Schäfer F, Tomsovic S. Friedel oscillations in microwave billiards. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:066210. [PMID: 20365257 DOI: 10.1103/physreve.80.066210] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Indexed: 05/29/2023]
Abstract
Friedel oscillations of electron densities near step edges have an analog in microwave billiards. A random plane-wave model, normally only appropriate for the eigenfunctions of a purely chaotic system, can be applied and is tested for non-purely-chaotic dynamical systems with measurements on pseudointegrable and mixed dynamics geometries. It is found that the oscillations in the pseudointegrable microwave cavity match the random plane-wave modeling. Separating the chaotic from the regular states for the mixed system requires incorporating an appropriate phase-space projection into the modeling in multiple ways for good agreement with experiment.
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Affiliation(s)
- A Bäcker
- Institut für Theoretische Physik, Technische Universität Dresden, Dresden, Germany
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Dietz B, Friedrich T, Miski-Oglu M, Richter A, Schäfer F, Seligmann TH. Nonperiodic echoes from quantum mushroom-billiard hats. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:036212. [PMID: 19905205 DOI: 10.1103/physreve.80.036212] [Citation(s) in RCA: 2] [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] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/24/2009] [Indexed: 05/28/2023]
Abstract
Nonperiodic tunable quantum echoes have been observed in experiments with an open microwave billiard whose geometry under certain conditions provides Fibonacci-like sequences of classical delay times. These sequences combined with the reflection at the opening induced by the wave character of the experiment and the size of the opening allow to shape quantum pulses. The pulses are obtained by response of an integrable scattering system.
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Affiliation(s)
- B Dietz
- Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
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Dietz B, Friedrich T, Harney HL, Miski-Oglu M, Richter A, Schäfer F, Verbaarschot J, Weidenmüller HA. Induced violation of time-reversal invariance in the regime of weakly overlapping resonances. Phys Rev Lett 2009; 103:064101. [PMID: 19792569 DOI: 10.1103/physrevlett.103.064101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Indexed: 05/28/2023]
Abstract
We measure the complex scattering amplitudes of a flat microwave cavity (a "chaotic billiard"). Time-reversal (T) invariance is partially broken by a magnetized ferrite placed within the cavity. We extend the random-matrix approach to T violation in scattering, determine the parameters from some properties of the scattering amplitudes, and successfully predict others. Our work constitutes the most precise test of the random-matrix theoretical approach to T violation so far available.
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Affiliation(s)
- B Dietz
- Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
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Greuner H, Böswirth B, Boscary J, Friedrich T, Lavergne C, Linsmeier C, Schlosser J, Wiltner A. Review of the high heat flux testing as an integrated part of W7-X divertor development. Fusion Engineering and Design 2009. [DOI: 10.1016/j.fusengdes.2008.12.083] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Boscary J, Greuner H, Friedrich T, Traxler H, Mendelevitch B, Böswirth B, Schlosser J, Smirnow M, Stadler R. Pre-series and testing route for the serial fabrication of W7-X target elements. Fusion Engineering and Design 2009. [DOI: 10.1016/j.fusengdes.2009.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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