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Link S, Loh G, Gartner M. Broncholithiasis – a rare initial presentation of lithopytsis. Am J Med Sci 2023. [DOI: 10.1016/s0002-9629(23)00485-8] [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: 01/28/2023]
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Born LI, Andree T, Frank S, Hübner J, Link S, Langheine M, Charlet A, Esser JS, Brehm R, Moser M. eif4ebp3l-A New Affector of Zebrafish Angiogenesis and Heart Regeneration? Int J Mol Sci 2022; 23:ijms231710075. [PMID: 36077472 PMCID: PMC9456460 DOI: 10.3390/ijms231710075] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
The eukaryotic initiation factor 4E binding protein (4E-BP) family is involved in translational control of cell proliferation and pro-angiogenic factors. The zebrafish eukaryotic initiation factor 4E binding protein 3 like (eif4ebp3l) is a member of the 4E-BPs and responsible for activity-dependent myofibrillogenesis, but whether it affects cardiomyocyte (CM) proliferation or heart regeneration is unclear. We examined eif4ebp3l during zebrafish vascular development and heart regeneration post cryoinjury in adult zebrafish. Using morpholino injections we induced silencing of eif4ebp3l in zebrafish embryos, which led to increased angiogenesis at 94 h post fertilization (hpf). For investigation of eif4ebp3l in cardiac regeneration, zebrafish hearts were subjected to cryoinjury. Regenerating hearts were analyzed at different time points post-cryoinjury for expression of eif4ebp3l by in situ hybridization and showed strongly decreased eif4ebp3l expression in the injured area. We established a transgenic zebrafish strain, which overexpressed eif4ebp3l under the control of a heat-shock dependent promotor. Overexpression of eif4ebp3l during zebrafish heart regeneration caused only macroscopically a reduced amount of fibrin at the site of injury. Overall, these findings demonstrate that silencing of eif4ebp3l has pro-angiogenic properties in zebrafish vascular development and when eif4ebp3l is overexpressed, fibrin deposition tends to be altered in zebrafish cardiac regeneration after cryoinjury.
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Affiliation(s)
- Lisa I. Born
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Institute of Anatomy, University of Veterinary Medicine of Hannover, Foundation, 30173 Hannover, Germany
- Correspondence:
| | - Theresa Andree
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Svenja Frank
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Judith Hübner
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Sandra Link
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Marion Langheine
- Institute of Anatomy, University of Veterinary Medicine of Hannover, Foundation, 30173 Hannover, Germany
| | - Anne Charlet
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Jennifer S. Esser
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Ralph Brehm
- Institute of Anatomy, University of Veterinary Medicine of Hannover, Foundation, 30173 Hannover, Germany
| | - Martin Moser
- Department of Cardiology and Angiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
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Qu AC, Nigge P, Link S, Levy G, Michiardi M, Spandar PL, Matthé T, Schneider M, Zhdanovich S, Starke U, Gutiérrez C, Damascelli A. Ubiquitous defect-induced density wave instability in monolayer graphene. Sci Adv 2022; 8:eabm5180. [PMID: 35675409 PMCID: PMC9177069 DOI: 10.1126/sciadv.abm5180] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Quantum materials are notoriously sensitive to their environments, where small perturbations can tip a system toward one of several competing ground states. Graphene hosts a rich assortment of such competing phases, including a bond density wave instability ("Kekulé distortion") that couples electrons at the K/K' valleys and breaks the lattice symmetry. Here, we report observations of a ubiquitous Kekulé distortion across multiple graphene systems. We show that extremely dilute concentrations of surface atoms (less than three adsorbed atoms every 1000 graphene unit cells) can self-assemble and trigger the onset of a global Kekulé density wave phase. Combining complementary momentum-sensitive angle-resolved photoemission spectroscopy (ARPES) and low-energy electron diffraction (LEED) measurements, we confirm the presence of this density wave phase and observe the opening of an energy gap. Our results reveal an unexpected sensitivity of the graphene lattice to dilute surface disorder and show that adsorbed atoms offer an attractive route toward designing novel phases in two-dimensional materials.
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Affiliation(s)
- A. C. Qu
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - P. Nigge
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - S. Link
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - G. Levy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - M. Michiardi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - P. L. Spandar
- Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA, USA
| | - T. Matthé
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - M. Schneider
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - S. Zhdanovich
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
| | - U. Starke
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - C. Gutiérrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
- Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA, USA
| | - A. Damascelli
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada
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Aguillon R, Madelaine R, Aguirrebengoa M, Guturu H, Link S, Dufourcq P, Lecaudey V, Bejerano G, Blader P, Batut J. Morphogenesis is transcriptionally coupled to neurogenesis during peripheral olfactory organ development. Development 2020; 147:226001. [PMID: 33144399 DOI: 10.1242/dev.192971] [Citation(s) in RCA: 4] [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: 05/17/2020] [Accepted: 10/28/2020] [Indexed: 01/04/2023]
Abstract
Sense organs acquire their distinctive shapes concomitantly with the differentiation of sensory cells and neurons necessary for their function. Although our understanding of the mechanisms controlling morphogenesis and neurogenesis in these structures has grown, how these processes are coordinated remains largely unexplored. Neurogenesis in the zebrafish olfactory epithelium requires the bHLH proneural transcription factor Neurogenin 1 (Neurog1). To address whether Neurog1 also controls morphogenesis, we analysed the migratory behaviour of early olfactory neural progenitors in neurog1 mutant embryos. Our results indicate that the oriented movements of these progenitors are disrupted in this context. Morphogenesis is similarly affected by mutations in the chemokine receptor gene, cxcr4b, suggesting it is a potential Neurog1 target gene. We find that Neurog1 directly regulates cxcr4b through an E-box cluster located just upstream of the cxcr4b transcription start site. Our results suggest that proneural transcription factors, such as Neurog1, directly couple distinct aspects of nervous system development.
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Affiliation(s)
- Raphaël Aguillon
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
| | - Romain Madelaine
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
| | - Marion Aguirrebengoa
- BigA Core Facility, Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
| | - Harendra Guturu
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Sandra Link
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Pascale Dufourcq
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
| | - Virginie Lecaudey
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Gill Bejerano
- Department of Developmental Biology, Department of Computer Science, Department of Pediatrics, Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
| | - Patrick Blader
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
| | - Julie Batut
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, 31062, France
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5
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Nigge P, Qu AC, Lantagne-Hurtubise É, Mårsell E, Link S, Tom G, Zonno M, Michiardi M, Schneider M, Zhdanovich S, Levy G, Starke U, Gutiérrez C, Bonn D, Burke SA, Franz M, Damascelli A. Room temperature strain-induced Landau levels in graphene on a wafer-scale platform. Sci Adv 2019; 5:eaaw5593. [PMID: 31723598 PMCID: PMC6839937 DOI: 10.1126/sciadv.aaw5593] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 09/17/2019] [Indexed: 05/17/2023]
Abstract
Graphene is a powerful playground for studying a plethora of quantum phenomena. One of the remarkable properties of graphene arises when it is strained in particular geometries and the electrons behave as if they were under the influence of a magnetic field. Previously, these strain-induced pseudomagnetic fields have been explored on the nano- and micrometer-scale using scanning probe and transport measurements. Heteroepitaxial strain, in contrast, is a wafer-scale engineering method. Here, we show that pseudomagnetic fields can be generated in graphene through wafer-scale epitaxial growth. Shallow triangular nanoprisms in the SiC substrate generate strain-induced uniform fields of 41 T, enabling the observation of strain-induced Landau levels at room temperature, as detected by angle-resolved photoemission spectroscopy, and confirmed by model calculations and scanning tunneling microscopy measurements. Our work demonstrates the feasibility of exploiting strain-induced quantum phases in two-dimensional Dirac materials on a wafer-scale platform, opening the field to new applications.
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Affiliation(s)
- P. Nigge
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - A. C. Qu
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - É. Lantagne-Hurtubise
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - E. Mårsell
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Division of Molecular and Condensed Matter Physics, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - S. Link
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - G. Tom
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - M. Zonno
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - M. Michiardi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - M. Schneider
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - S. Zhdanovich
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - G. Levy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - U. Starke
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - C. Gutiérrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - D. Bonn
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - S. A. Burke
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Corresponding author. (S.A.B.); (M.F.); (A.D.)
| | - M. Franz
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Corresponding author. (S.A.B.); (M.F.); (A.D.)
| | - A. Damascelli
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Corresponding author. (S.A.B.); (M.F.); (A.D.)
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6
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Esser JS, Steiner RE, Deckler M, Schmitt H, Engert B, Link S, Charlet A, Patterson C, Bode C, Zhou Q, Moser M. Extracellular bone morphogenetic protein modulator BMPER and twisted gastrulation homolog 1 preserve arterial-venous specification in zebrafish blood vessel development and regulate Notch signaling in endothelial cells. FEBS J 2018; 285:1419-1436. [PMID: 29473997 DOI: 10.1111/febs.14414] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [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: 09/29/2017] [Revised: 01/26/2018] [Accepted: 02/19/2018] [Indexed: 01/16/2023]
Abstract
The bone morphogenetic protein (BMP) signaling pathway plays a central role during vasculature development. Mutations or dysregulation of the BMP pathway members have been linked to arteriovenous malformations. In the present study, we investigated the effect of the BMP modulators bone morphogenetic protein endothelial precursor-derived regulator (BMPER) and twisted gastrulation protein homolog 1 (TWSG1) on arteriovenous specification during zebrafish development and analyzed downstream Notch signaling pathway in human endothelial cells. Silencing of bmper and twsg1b in zebrafish embryos by morpholinos resulted in a pronounced enhancement of venous ephrinB4a marker expression and concomitant dysregulated arterial ephrinb2a marker expression detected by in situ hybridization. As arteriovenous specification was disturbed, we assessed the impact of BMPER and TWSG1 protein stimulation on the Notch signaling pathway on endothelial cells from different origin. Quantitative real-time PCR (qRT-PCR) and western blot analysis showed increased expression of Notch target gene hairy and enhancer of split, HEY1/2 and EPHRINB2. Consistently, silencing of BMPER in endothelial cells by siRNAs decreased Notch signaling and downstream effectors. BMP receptor antagonist DMH1 abolished BMPER and BMP4 induced Notch signaling pathway activation. In conclusion, we found that in endothelial cells, BMPER and TWSG1 are necessary for regular Notch signaling activity and in zebrafish embryos BMPER and TWSG1 preserve arteriovenous specification to prevent malformations.
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Affiliation(s)
- Jennifer Susanne Esser
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Rahel Elisabeth Steiner
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Meike Deckler
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Hannah Schmitt
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Bianca Engert
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Sandra Link
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Anne Charlet
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Cam Patterson
- Weill Cornell Medical Center, New York Presbyterian Hospital, NY, USA
| | - Christoph Bode
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Qian Zhou
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
| | - Martin Moser
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University Freiburg, Germany
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Sforzini J, Hapala P, Franke M, van Straaten G, Stöhr A, Link S, Soubatch S, Jelínek P, Lee TL, Starke U, Švec M, Bocquet FC, Tautz FS. Structural and Electronic Properties of Nitrogen-Doped Graphene. Phys Rev Lett 2016; 116:126805. [PMID: 27058093 DOI: 10.1103/physrevlett.116.126805] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Indexed: 06/05/2023]
Abstract
We investigate the structural and electronic properties of nitrogen-doped epitaxial monolayer graphene and quasifreestanding monolayer graphene on 6H-SiC(0001) by the normal incidence x-ray standing wave technique and by angle-resolved photoelectron spectroscopy supported by density functional theory simulations. With the location of various nitrogen species uniquely identified, we observe that for the same doping procedure, the graphene support, consisting of substrate and interface, strongly influences the structural as well as the electronic properties of the resulting doped graphene layer. Compared to epitaxial graphene, quasifreestanding graphene is found to contain fewer nitrogen dopants. However, this lack of dopants is compensated by the proximity of nitrogen atoms at the interface that yield a similar number of charge carriers in graphene.
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Affiliation(s)
- J Sforzini
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - P Hapala
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - M Franke
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - G van Straaten
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - A Stöhr
- Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany
| | - S Link
- Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany
| | - S Soubatch
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - P Jelínek
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - T-L Lee
- Diamond Light Source Ltd, Didcot OX110DE, Oxfordshire, United Kingdom
| | - U Starke
- Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany
| | - M Švec
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague, Czech Republic
| | - F C Bocquet
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - F S Tautz
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
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8
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Agarwala S, Duquesne S, Liu K, Boehm A, Grimm L, Link S, König S, Eimer S, Ronneberger O, Lecaudey V. Amotl2a interacts with the Hippo effector Yap1 and the Wnt/β-catenin effector Lef1 to control tissue size in zebrafish. eLife 2015; 4:e08201. [PMID: 26335201 PMCID: PMC4596637 DOI: 10.7554/elife.08201] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [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: 04/18/2015] [Accepted: 09/02/2015] [Indexed: 12/17/2022] Open
Abstract
During development, proliferation must be tightly controlled for organs to reach their appropriate size. While the Hippo signaling pathway plays a major role in organ growth control, how it senses and responds to increased cell density is still unclear. In this study, we use the zebrafish lateral line primordium (LLP), a group of migrating epithelial cells that form sensory organs, to understand how tissue growth is controlled during organ formation. Loss of the cell junction-associated Motin protein Amotl2a leads to overproliferation and bigger LLP, affecting the final pattern of sensory organs. Amotl2a function in the LLP is mediated together by the Hippo pathway effector Yap1 and the Wnt/β-catenin effector Lef1. Our results implicate for the first time the Hippo pathway in size regulation in the LL system. We further provide evidence that the Hippo/Motin interaction is essential to limit tissue size during development. DOI:http://dx.doi.org/10.7554/eLife.08201.001 How do organs and tissues know when to stop growing? A cell communication pathway known as Hippo signaling plays a central role as it can tell cells to stop dividing. It is activated when cells in developing tissues come into contact with each other and causes a protein called Yap1 to be modified, which prevents it from entering the cell nucleus to activate genes that are involved in cell division. In a zebrafish embryo, an organ called the lateral line forms from a cluster of cells that migrate along the embryo's length. At regular intervals, the cluster deposits small bunches of cells from its trailing end. The resulting loss of cells from the cluster is balanced by cell division at the front of the cluster, which is triggered by another signaling pathway called Wnt signaling. A protein of the ‘Motin’ family called Amotl2a is present in this migrating cluster. Motin proteins form junctions between cells and inhibit the activity of Yap1, but it is not known whether they are involved in regulating the size of organs. Here, Agarwala et al. used the lateral line as a model to study the control of organ size in zebrafish embryos. The experiments show that when Amotl2a is absent, the migrating cell cluster becomes larger, with the highest levels of cell division occurring at its trailing end. Yap1 and a protein involved in Wnt signaling called Lef1 are also present in the cluster and are required for it to be normal in size. In zebrafish that lack Amotl2a, the additional loss of Yap1 prevents this cluster from becoming too large. From these and other results, it appears that Amotl2a regulates the size of the lateral line cell cluster by restricting the ability of Yap1 and Lef1 to promote cell division. Agarwala et al.'s findings demonstrate a role for Amotl2a in controlling the size of organs. A future challenge is to understand the details of how it restricts the activities of Yap1 and Lef1. DOI:http://dx.doi.org/10.7554/eLife.08201.002
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Affiliation(s)
- Sobhika Agarwala
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Developmental Biology, Institute for Biology I, Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Sandra Duquesne
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Developmental Biology, Institute for Biology I, Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Kun Liu
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Image Analysis Lab, Institute for Computer Science, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Anton Boehm
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Image Analysis Lab, Institute for Computer Science, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Lin Grimm
- Developmental Biology, Institute for Biology I, Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Sandra Link
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Developmental Biology, Institute for Biology I, Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Sabine König
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Stefan Eimer
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,ZBSA Center for Biological Systems Analysis, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Olaf Ronneberger
- BIOSS Centre for Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany.,Image Analysis Lab, Institute for Computer Science, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
| | - Virginie Lecaudey
- Developmental Biology, Institute for Biology I, Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg im Breisgau, Germany
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Gierz I, Calegari F, Aeschlimann S, Chávez Cervantes M, Cacho C, Chapman RT, Springate E, Link S, Starke U, Ast CR, Cavalleri A. Tracking Primary Thermalization Events in Graphene with Photoemission at Extreme Time Scales. Phys Rev Lett 2015; 115:086803. [PMID: 26340199 DOI: 10.1103/physrevlett.115.086803] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Indexed: 05/13/2023]
Abstract
Direct and inverse Auger scattering are amongst the primary processes that mediate the thermalization of hot carriers in semiconductors. These two processes involve the annihilation or generation of an electron-hole pair by exchanging energy with a third carrier, which is either accelerated or decelerated. Inverse Auger scattering is generally suppressed, as the decelerated carriers must have excess energies higher than the band gap itself. In graphene, which is gapless, inverse Auger scattering is, instead, predicted to be dominant at the earliest time delays. Here, <8 fs extreme-ultraviolet pulses are used to detect this imbalance, tracking both the number of excited electrons and their kinetic energy with time-and angle-resolved photoemission spectroscopy. Over a time window of approximately 25 fs after absorption of the pump pulse, we observe an increase in conduction band carrier density and a simultaneous decrease of the average carrier kinetic energy, revealing that relaxation is in fact dominated by inverse Auger scattering. Measurements of carrier scattering at extreme time scales by photoemission will serve as a guide to ultrafast control of electronic properties in solids for petahertz electronics.
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Affiliation(s)
- I Gierz
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - F Calegari
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
- Institute for Photonics and Nanotechnologies, IFN-CNR, 20133 Milano, Italy
| | - S Aeschlimann
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - M Chávez Cervantes
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - C Cacho
- Central Laser Facility, STFC Rutherford Appleton Laboratory, OX11 0QX Harwell, United Kingdom
| | - R T Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, OX11 0QX Harwell, United Kingdom
| | - E Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, OX11 0QX Harwell, United Kingdom
| | - S Link
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - U Starke
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - C R Ast
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - A Cavalleri
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
- Department of Physics, Clarendon Laboratory, University of Oxford, OX1 3PU Oxford, United Kingdom
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Spoerri I, Scherer K, Michel S, Link S, Bircher AJ, Heijnen IAFM. Detection of nickel and palladium contact hypersensitivity by a flow cytometric lymphocyte proliferation test. Allergy 2015; 70:323-7. [PMID: 25443647 DOI: 10.1111/all.12553] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2014] [Indexed: 11/30/2022]
Abstract
We established a flow cytometric lymphocyte proliferation test (LPT) for the detection of nickel (Ni) and palladium (Pd) sensitization. Eighty-one consecutive patients with an indication for patch test (PT) were tested by LPT with Ni (NiSO4 ) and Pd (Na2 PdCl4 and PdCl2 ) salts. The imprecision of the LPT was low (coefficient of variation 7.2%). Using PT as a diagnostic reference, the sensitivity and specificity of LPT were 74.4% and 80% for NiSO4 , 74.4% and 78.3% for Na2 PdCl4 , and 57.2% and 85.4% for PdCl2 , respectively. For both Ni and Pd, the likelihood ratio for a positive PT markedly increased with increasing LPT value. With medical history as a reference, the sensitivity and specificity were 40.6% and 82.1% for LPT and 59.4% and 89.7% for PT, respectively. Combination of LPT and PT resulted in a higher specificity of 95%, albeit lower sensitivity of 34.4%. In conclusion, flow cytometric LPT represents a reliable and useful method for the detection of Ni and Pd sensitization. LPT values correlate with PT results and, when used in combination with PT, increase test specificity.
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Affiliation(s)
- I. Spoerri
- Research Group of Dermatology; Department of Biomedicine; University Hospital Basel; University of Basel; Basel Switzerland
| | - K. Scherer
- Allergy Unit; Department of Dermatology; University Hospital Basel; Basel Switzerland
| | - S. Michel
- Allergy Unit; Department of Dermatology; University Hospital Basel; Basel Switzerland
| | - S. Link
- Medical Immunology, Laboratory Medicine; University Hospital Basel; Basel Switzerland
| | - A. J. Bircher
- Allergy Unit; Department of Dermatology; University Hospital Basel; Basel Switzerland
| | - I. A. F. M. Heijnen
- Medical Immunology, Laboratory Medicine; University Hospital Basel; Basel Switzerland
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Fischer FSU, Tremel K, Saur AK, Link S, Kayunkid N, Brinkmann M, Herrero-Carvajal D, Navarrete JTL, Delgado MCR, Ludwigs S. Influence of Processing Solvents on Optical Properties and Morphology of a Semicrystalline Low Bandgap Polymer in the Neutral and Charged States. Macromolecules 2013. [DOI: 10.1021/ma400939z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F. S. U. Fischer
- IPOC-Functional Polymers, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - K. Tremel
- IPOC-Functional Polymers, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - A.-K. Saur
- IPOC-Functional Polymers, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - S. Link
- IPOC-Functional Polymers, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - N. Kayunkid
- Institut Charles Sadron (UPR22), CNRS 23 rue du Loess, 67034 Strasbourg Cedex 2, France
| | - M. Brinkmann
- Institut Charles Sadron (UPR22), CNRS 23 rue du Loess, 67034 Strasbourg Cedex 2, France
| | - D. Herrero-Carvajal
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n,
Málaga 29071, Spain
| | - J. T. López Navarrete
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n,
Málaga 29071, Spain
| | - M. C. Ruiz Delgado
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n,
Málaga 29071, Spain
| | - S. Ludwigs
- IPOC-Functional Polymers, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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Burda C, Green TC, Link S, El-Sayed MA. Femtosecond Interfacial Electron Transfer Dynamics of CdSe Semiconductor Nanoparticles. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-536-419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe effect of the adsorption of an electron donor (thiophenol, TP) on the surface of CdSe nanoparticles (NPs) on the emission and electron-hole dynamics is studied. It is found that while the emission is completely quenched, the effect on the transient bleach recovery of the band gap absorption is only slight. This is explained by a mechanism in which the hole in the valence band of the NP is rapidly neutralized by electron transfer from the TP. However, the excited electron in the conduction band is not transferred to the TP cation, i. e. the electron does not shuttle via the organic moiety as it does when naphthoquinone is adsorbed [1]. The excited electron is rather trapped by surface states. Thus the rate of bleach recovery in the CdSe NP system is determined by the rate of electron trapping and not by hole trapping. Comparable conclusions resulted previously [2] for the CdS NP when the CdS-MV2+ system is studied. A comparative discussion of the electron-hole dynamics in these systems (CdSe-NQ, CdS-MV2+ and CdSe-TP) is given.
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Lee K, Link S, Ge L. Photographic Memory of Unfamiliar Faces Under 30 Seconds. J Vis 2010. [DOI: 10.1167/10.7.619] [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] Open
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Tcherniak A, Ha JW, Dominguez-Medina S, Slaughter LS, Link S. Probing a century old prediction one plasmonic particle at a time. Nano Lett 2010; 10:1398-1404. [PMID: 20196552 DOI: 10.1021/nl100199h] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In 1908, Gustav Mie solved Maxwell's equations to account for the absorption and scattering of spherical plasmonic particles. Since then much attention has been devoted to the size dependent optical properties of metallic nanoparticles. However, ensemble measurements of colloidal solutions generally only yield the total extinction cross sections of the nanoparticles. Here, we show how Mie's prediction on the size dependence of the surface absorption and scattering can be probed separately for the same gold nanoparticle by using two single particle spectroscopy techniques, (1) dark-field scattering and (2) photothermal imaging, which selectively only measure scattering and absorption, respectively. Combining the optical measurements with correlated scanning electron microscopy furthermore allowed us to measure the size of the spherical gold nanoparticles, which ranged from 43 to 274 nm in diameter. We found that even though the trend predicted by Mie theory is followed well by the experimental data over a large range of nanoparticle diameters, for small size variations changes in scattering and absorption intensities are dominated by factors other than those considered by Mie theory. In particular, spectral shifts of the plasmon resonance due to deviations from a spherical particle shape alone cannot explain the observed variation in absorption and scattering intensities.
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Affiliation(s)
- A Tcherniak
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
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Link S, Osterhues HH, Erné SN. Software-Plattform für die Analyse elektro- und magnetokardiographischer Datenbanken. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.1998.43.s1.96] [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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Abstract
A combination of single-molecule spectroscopy and analysis with simulations is used to provide detailed information about the structural and dynamic properties of a fluorescent polymer MEH-PPV (poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene]) immersed in a nematic and smectic solvent. In nematic solvents, single-polymer molecules are oriented strongly along the solvent director, much more so than the solvent molecules, confirming Onsager's old prediction. The diffusion anisotropy parallel and perpendicular to the solvent director, however, is less than two, which is similar to that of a spherical colloid in a nematic solvent. In smectic solvents, there is a second orientation of the dissolved polymer perpendicular to the solvent director, which we hypothesize is caused by the polymer occupying the interlayer volume. The research discussed here emphasizes the importance of organization in complex fluids and suggests that the interplay of order on different length scales could be exploited to fabricate novel nanostructured materials.
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Affiliation(s)
- P F Barbara
- Center for Nano- and Molecular Science and Technology, and Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA.
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Weise A, Rodriguez-Franco M, Timm B, Hermann M, Link S, Jost W, Gorr G. Use of Physcomitrella patens actin 5' regions for high transgene expression: importance of 5' introns. Appl Microbiol Biotechnol 2006. [PMID: 16059684 DOI: 10.1007/s00253-005-0087-86] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We have isolated four actin (Act) genes from Physcomitrella patens and used their corresponding 5' regions for recombinant expression of the human vascular endothelial growth factor (rhVEGF121) in transiently transformed Physcomitrella protoplasts and in stable transformed lines. In the transient system, we found up to 11-fold activity of the corresponding 5' regions as compared with that of the plant constitutive 35S promoter. Moreover, the use of an optimised expression vector in which the human VEGF signal peptide was exchanged with a plant signal peptide resulted in an additional 7-fold increase in secreted rhVEGF. We found that the 5' introns of PpAct1, PpAct5 and PpAct7 are essential for high expression. The enhancing mechanisms of the introns, however, seem to be different since in the case of PpAct1, the expression level is stimulated only in the presence of the endogenous promoter, whereas the 5' introns of PpAct5 and PpAct7 stimulate expression also in combination with the 35S promoter. Beyond this, the isolated 5' regions are shown to be useful for high expression levels in transgenic moss lines with values of secreted rhVEGF up to 96 microg g(-1) dry weight.
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Affiliation(s)
- Andreas Weise
- greenovation Biotech GmbH, Bötzinger Str. 29b, 79111, Freiburg, Germany
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Abstract
We examine the effect of polymer chain segmentation on the recently discovered ability of nematic solvents to elongate and align polymer chain solutes. Coordinated single molecule spectroscopy and beads-on-a-chain simulations are used to study the orientational and conformational order of a series of segmented conjugated polymers, dissolved in the nematic liquid crystal 5CB. The order parameters for alignment and elongation are both observed to decrease with increasing segmentation, reflecting an interplay among conformational entropy, solvation anisotropy, and bending energy of the chain.
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Affiliation(s)
- S Link
- Center for Nano- and Molecular Science and Technology, University of Texas at Austin, Austin, Texas 78712, USA
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Weise A, Rodriguez-Franco M, Timm B, Hermann M, Link S, Jost W, Gorr G. Use of Physcomitrella patens actin 5' regions for high transgene expression: importance of 5' introns. Appl Microbiol Biotechnol 2005; 70:337-45. [PMID: 16059684 DOI: 10.1007/s00253-005-0087-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 07/02/2005] [Accepted: 07/03/2005] [Indexed: 11/28/2022]
Abstract
We have isolated four actin (Act) genes from Physcomitrella patens and used their corresponding 5' regions for recombinant expression of the human vascular endothelial growth factor (rhVEGF121) in transiently transformed Physcomitrella protoplasts and in stable transformed lines. In the transient system, we found up to 11-fold activity of the corresponding 5' regions as compared with that of the plant constitutive 35S promoter. Moreover, the use of an optimised expression vector in which the human VEGF signal peptide was exchanged with a plant signal peptide resulted in an additional 7-fold increase in secreted rhVEGF. We found that the 5' introns of PpAct1, PpAct5 and PpAct7 are essential for high expression. The enhancing mechanisms of the introns, however, seem to be different since in the case of PpAct1, the expression level is stimulated only in the presence of the endogenous promoter, whereas the 5' introns of PpAct5 and PpAct7 stimulate expression also in combination with the 35S promoter. Beyond this, the isolated 5' regions are shown to be useful for high expression levels in transgenic moss lines with values of secreted rhVEGF up to 96 microg g(-1) dry weight.
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Affiliation(s)
- Andreas Weise
- greenovation Biotech GmbH, Bötzinger Str. 29b, 79111, Freiburg, Germany
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Link S, El-Sayed MA. Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant. J Phys Chem B 2005. [DOI: 10.1021/jp058091f] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jost W, Link S, Horstmann V, Decker EL, Reski R, Gorr G. Isolation and characterisation of three moss-derived beta-tubulin promoters suitable for recombinant expression. Curr Genet 2004; 47:111-20. [PMID: 15605251 DOI: 10.1007/s00294-004-0555-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [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: 08/27/2004] [Revised: 11/12/2004] [Accepted: 11/16/2004] [Indexed: 10/26/2022]
Abstract
The moss Physcomitrella patens is an excellent tool to study plant gene-function relationships due to its high rate of homologous recombination (HR). It has also been shown to be very useful in the production of recombinant proteins which are secreted into a simple medium. Thus, there is a need for suitable promoters functional in this well established model organism. We isolated genomic flanking regions of the beta-tubulin gene family from Physcomitrella, concentrating on those family members showing high transcript abundance integrated over gametophytic tissues. Using a novel, fast and reliable quantification assay based on the transient expression and secretion of a recombinant human protein, three genomic upstream regions were characterised in serial deletion constructs. Expression rates were up to three times higher than those obtained with the 35S cauliflower mosaic virus (35S) promoter, which served as a reference.
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Affiliation(s)
- Wolfgang Jost
- Greenovation Biotech GmbH, Bötzinger Strasse 29b, 79111 Freiburg, Germany
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Marcinkeviciene J, Rogers MJ, Kopcho L, Jiang W, Wang K, Murphy DJ, Lippy J, Link S, Chung TD, Hobbs F, Haque T, Trainor GL, Slee A, Stern AM, Copeland RA. Selective inhibition of bacterial dihydroorotate dehydrogenases by thiadiazolidinediones. Biochem Pharmacol 2000; 60:339-42. [PMID: 10856428 DOI: 10.1016/s0006-2952(00)00348-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [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: 10/18/2022]
Abstract
Dihydroorotate dehydrogenase is a critical enzyme of de novo pyrimidine biosynthesis in prokaryotic and eukaryotic cells. Differences in the primary structure of the enzymes from Gram-positive and -negative bacteria and from mammals indicate significant structural divergence among these enzymes. We have identified a class of small molecules, the thiadiazolidinediones, that inhibit prototypical enzymes from Gram-positive and -negative bacteria, but are inactive against the human enzyme. The most potent compound in our collection functioned as a time-dependent irreversible inactivator of the bacterial enzymes with k(inact)/K(i) values of 48 and 500 M(-1) sec(-1) for the enzymes from Escherichia coli and Enterococcus faecalis, respectively. The data presented here indicate that it is possible to inhibit prokaryotic dihydroorotate dehydrogenases selectively while sparing the mammalian enzyme. Thus, this enzyme may represent a valuable target for the development of novel antibiotic compounds.
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Affiliation(s)
- J Marcinkeviciene
- Department of Chemical Enzymology, The DuPont Pharmaceuticals Co., Wilmington, DE 19880-0400, USA
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Burda C, Abdel-Kader MH, Link S, El-Sayed MA. Femtosecond Dynamics of a Simple Merocyanine Dye: Does Deprotonation Compete with Isomerization? J Am Chem Soc 2000. [DOI: 10.1021/ja993940w] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Burda
- Contribution from the Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, and National Institute for Laser Enhanced Science, Cairo University, Egypt
| | - M. H. Abdel-Kader
- Contribution from the Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, and National Institute for Laser Enhanced Science, Cairo University, Egypt
| | - S. Link
- Contribution from the Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, and National Institute for Laser Enhanced Science, Cairo University, Egypt
| | - M. A. El-Sayed
- Contribution from the Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, and National Institute for Laser Enhanced Science, Cairo University, Egypt
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Link S, Burda C, Nikoobakht B, El-Sayed MA. Laser-Induced Shape Changes of Colloidal Gold Nanorods Using Femtosecond and Nanosecond Laser Pulses. J Phys Chem B 2000. [DOI: 10.1021/jp000679t] [Citation(s) in RCA: 649] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Link
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - C. Burda
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - B. Nikoobakht
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - M. A. El-Sayed
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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Link S, Häring G, Hedderich J. [Effect of phacoemulsification and posterior chamber lens implantation on intraocular pressure in patients with and without open-angle glaucoma]. Ophthalmologe 2000; 97:402-6. [PMID: 10916382 DOI: 10.1007/s003470070088] [Citation(s) in RCA: 9] [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] [Indexed: 11/25/2022]
Abstract
BACKGROUND Many of the previous studies which dealt with the influence of cataract surgery on intraocular pressure, were performed retrospectively and based on heterogeneous groups of patients. Therefore, the purpose of our study was to prospectively assess the effect of phacoemulsification and posterior chamber intraocular-lens (IOL)-implantation on intraocular pressure (IOP) under standardized conditions in patients with and without open-angle-glaucoma. PATIENTS AND METHODS Overall 52 patients were recruited for the study. 34 eyes with normal IOP and 16 eyes with open-angle-glaucoma were operated with the same technique. RESULTS Mean IOP in patients with cataract and without glaucoma was preoperatively 15.1 mmHg. 6 months postoperatively these patients showed a mean decrease of IOP of 11.9% (1.8 mmHg +/- 3.8; p = 0.027); after 12 months IOP showed a decrease of 18.5% (2.8 mmHg +/- 3.5; p = 0.0001). In patients with glaucoma mean IOP was preoperatively 17.3 mmHg. IOP was reduced by 23.7% (4.1 mmHg +/- 6.0; p = 0.017) 6 months after cataract surgery and 22.6% (3.9 mmHg +/- 4.5; p = 0.005) 12 months after the operation. In 6 of 16 eyes the antiglaucoma medication could be suspended. CONCLUSION Reduction of IOP is a positive side effect of phacoemulsification and posterior chamber IOL implantation and should be considered when indicating cataract surgery in patients with glaucoma and only slight elevation of IOP.
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Affiliation(s)
- S Link
- Klinik für Ophthalmologie der Christian-Albrechts-Universität zu Kiel
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Berg W, Linder C, Eschholz G, Link S, Schubert J. Possibility of improving the acceptance rateof early detection testing for prostate cancerwith a one-step test for prostate-specific antigen in whole blood. Urol Int 1999; 63:102-6. [PMID: 10592497 DOI: 10.1159/000030426] [Citation(s) in RCA: 9] [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] [Indexed: 11/19/2022]
Abstract
In order to increase the acceptance rate of early detection testing for prostate cancer, a qualitative prostate-specific antigen (PSA) one-step test has been developed. Determining the PSA level with this test system takes 10 min. The blood samples of 190 men were tested in this qualitative assay, which uses 50 microl of EDTA whole blood and in which the results are ascertained visually. Parallel samples were tested in serum-based, quantitative assays (Abbott Imx, EIA). The findings of the two kinds of assays were compared and evaluated regarding their correspondence (<4.0 and > or = 4.0 ng/ml). For the 74 blood samples in which the quantitative assay showed PSA levels <4.0 ng/ml, the PSA one-step test showed 83.8% correct negative results (corresponds to diagnostic specificity). For the 116 samples in which the classic assay showed PSA levels > or = 4.0 ng/ml, the one-step test showed 90.5% correct positive results (sensitivity). The noted deviations appear especially around the cut-off value of 4.0 ng/ml, i.e. within the PSA concentration range of 3.0 < 4.0 and 4.0 < 5.0 ng/ml. The qualitative PSA one-step test presented here demonstrates good reproducibility. It can be conducted by the patient and is easy to use. The test offers a simple, feasible method for early detection programs for prostate cancer.
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Affiliation(s)
- W Berg
- Department of Urology, University Hospital, Friedrich Schiller University, Jena, Germany.
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Burda C, Link S, Green TC, El-Sayed MA. New Transient Absorption Observed in the Spectrum of Colloidal CdSe Nanoparticles Pumped with High-Power Femtosecond Pulses. J Phys Chem B 1999. [DOI: 10.1021/jp991503y] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. Burda
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - S. Link
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - T. C. Green
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - M. A. El-Sayed
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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Link S, Burda C, Wang ZL, El-Sayed MA. Electron dynamics in gold and gold–silver alloy nanoparticles: The influence of a nonequilibrium electron distribution and the size dependence of the electron–phonon relaxation. J Chem Phys 1999. [DOI: 10.1063/1.479310] [Citation(s) in RCA: 292] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Link S, Wang ZL, El-Sayed MA. Alloy Formation of Gold−Silver Nanoparticles and the Dependence of the Plasmon Absorption on Their Composition. J Phys Chem B 1999. [DOI: 10.1021/jp990387w] [Citation(s) in RCA: 1173] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Link
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, and School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Z. L. Wang
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, and School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - M. A. El-Sayed
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, and School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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Link S, Mohamed MB, El-Sayed MA. Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant. J Phys Chem B 1999. [DOI: 10.1021/jp990183f] [Citation(s) in RCA: 1267] [Impact Index Per Article: 50.7] [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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Burda C, Green TC, Link S, El-Sayed MA. Electron Shuttling Across the Interface of CdSe Nanoparticles Monitored by Femtosecond Laser Spectroscopy. J Phys Chem B 1999. [DOI: 10.1021/jp9843050] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Burda
- Laser Dynamics Laboratory, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - T. C. Green
- Laser Dynamics Laboratory, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - S. Link
- Laser Dynamics Laboratory, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - M. A. El-Sayed
- Laser Dynamics Laboratory, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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Link S, Burda C, Mohamed MB, Nikoobakht B, El-Sayed MA. Laser Photothermal Melting and Fragmentation of Gold Nanorods: Energy and Laser Pulse-Width Dependence. J Phys Chem A 1999. [DOI: 10.1021/jp983141k] [Citation(s) in RCA: 420] [Impact Index Per Article: 16.8] [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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Link S, Osterhues HH, Erné SN. [Software platform for analysis of electro- and magnetocardiography databanks]. BIOMED ENG-BIOMED TE 1998; 43 Suppl:96-7. [PMID: 9859275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- S Link
- Arbeitsbereich Erfassung und Verarbeitung von Biosignalen, Universität Ulm
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Abstract
This study was conducted to investigate a possible etiological role of chlorinated hydrocarbons in the pathogenesis of repeated miscarriages. The blood levels of chlorinated hydrocarbons [CHCs: pentachlorophenol, hexachlorocyclohexane, hexachlorobenzene, the dichlorodiphenyltrichloroethane (DDT) group, polychlorinated biphenyls] were determined in 89 women with repeated miscarriages, who were referred to the University Hospital of Obstetrics and Gynecology of Heidelberg for investigations between 1989 and 1993, and compared to a previously investigated reference population. In more than 20% of the women, at least one of the CHC levels exceeded the reference range. CHC levels did not differ significantly between women with primary or secondary and early or late miscarriages; neither did they differ between women with hormonal or immunological disorders as causes of repeated miscarriages or women with idiopathic repeated miscarriages. No significant associations were detected between CHC levels and further conceptions or the outcome of further pregnancies. As significant associations were found between increasing CHC blood concentrations and immunological and hormonal changes, CHCs may have an impact on the pregnancy course in certain cases.
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Affiliation(s)
- I Gerhard
- Department of Gynecological Endocrinology and Reproduction, Women's Hospital, Department of Transplantation Immunology, University of Heidelberg, Heidelberg, Germany
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Little RB, Burda C, Link S, Logunov S, El-Sayed MA. Charge Separation Effects on the Rate of Nonradiative Relaxation Processes in Quantum Dots−Quantum Well Heteronanostructures. J Phys Chem A 1998. [DOI: 10.1021/jp9822687] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. B. Little
- Laser Dynamics Laboratory, Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, Georgia 30332-0400
| | - C. Burda
- Laser Dynamics Laboratory, Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, Georgia 30332-0400
| | - S. Link
- Laser Dynamics Laboratory, Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, Georgia 30332-0400
| | - S. Logunov
- Laser Dynamics Laboratory, Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, Georgia 30332-0400
| | - M. A. El-Sayed
- Laser Dynamics Laboratory, Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, Georgia 30332-0400
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Abstract
The glycoprotein CD14 acts as a receptor for lipopolysaccharide (LPS), either when anchored in the myeloid cell membrane (mCD14) or as a soluble molecule (sCD14) in serum. sCD14-LPS complexes activate cells devoid of mCD14. However, the role of sCD14 independent of LPS is unknown. Therefore, the effect of sCD14 on monocyte functions was investigated in the monocytic cell lines THP1 and Mono Mac 6 and in fresh human monocytes. Under serum-free conditions, endotoxin-free human recombinant sCD14(1-348), (rsCD14(1-348)) induced tumor necrosis factor alpha (TNF-alpha). The TNF-alpha effect was stronger in THP1 cells than in Mono Mac 6 cells or monocytes. It was dose dependent, with a maximum at 1 microg/ml, and time dependent, with a maximum after 2 h. sCD14 purified from urine had the same cytokine-activating capacity. In contrast, C-terminally truncated rsCD14(1-152) was inactive. The rsCD14 effect was not due to LPS contamination, since it was resistant to polymyxin and lipid IVa but sensitive to heat and trypsin. The rsCD14-induced cytokine induction was blocked by preincubation of rsCD14 with a monoclonal anti-CD14 antibody that did not recognize the LPS-binding site. Release of the TNF-alpha disappeared upon pretreatment of rsCD14 in 50% plasma or in complete, heat-inactivated or sCD14-depleted serum. Moreover, cytokine production was no longer observed when rsCD14 was pretreated with thrombocytes. The thrombocyte effect was dose and time dependent. In conclusion, sCD14 is able to activate myeloid cells, and the effect is prevented by the presence of plasma, serum, or thrombocytes.
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Affiliation(s)
- R Landmann
- Department of Research, Medicine University Hospital, Basel, Switzerland
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Link S. William James McGill (1922-1997). J Math Psychol 1998; 42:1-4. [PMID: 9606158 DOI: 10.1006/jmps.1998.1208] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Copyright
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Affiliation(s)
- S Link
- Link Psychophysical Laboratory Department of Psychology, McMaster University
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Hurlebaus AE, Link S. The effects of an aggressive behavior management program on nurses' levels of knowledge, confidence, and safety. J Nurs Staff Dev 1997; 13:260-265. [PMID: 9362823] [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: 05/22/2023]
Abstract
Violence in the workplace is increasing, and unfortunately, hospitals are not exempt from the problem. Nurses are the primary caregivers in hospitals and are more likely to encounter violence because of the amount of time spent in direct patient care. Many nurses have not been trained to manage explosive situations. This project was developed to provide a program titled, "Managing Aggressive Behavior," to nurses and to measure and compare the differences in levels of knowledge and feelings of safety and confidence among nurses who attended the workshop versus a group who did not. The data revealed a significant difference in knowledge in the program group (P < 0.001) but no significant changes in safety (P = 0.367) or confidence (P = 0.440). No significant changes were found among the variables in the treatment group. Suggestions for further research and teaching are given.
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Abstract
Monocyte phenotypes and functions were studied in 22 patients with major depression, and compared with those of 22 matched healthy controls. Immune measures were performed before and after dexamethasone suppression, and after 4 and 12 weeks of moclobemide therapy in patients. Seven patients terminated after 4 weeks because of treatment failure; 11 out of 15 patients responded to therapy after 12 weeks. Monocyte human leukocyte antigen class II and CD14 antigen expression, tumor necrosis factor production, and plasma interferon-gamma and neopterin did not differ in patients before treatment and controls. The reaction to dexamethasone was also similar in patients and controls. Neither antidepressive treatment per se nor the clinical response to it affected any immunological parameter. In conclusion, corticosteroid-controlled monocyte functions were similar in untreated and treated depressed patients and in controls, and unrelated to the clinical course of the disease.
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Affiliation(s)
- R Landmann
- Department of Research, University Hospital, Basel, Switzerland
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Abstract
Membrane CD14 is involved in lipopolysaccharide (LPS)-induced monocyte activation; it binds LPS, and antibodies against CD14 block the effects of low-dose LPS. It is unknown how LPS regulates its own receptor CD14 in vitro. Therefore, we investigated the effects of LPS on CD14 mRNA and membrane and soluble CD14 (mCD14 and sCD14, respectively) in human monocytes and macrophages. No changes were observed during the first 3 h of LPS stimulation. After 6 to 15 h, LPS weakly reduced CD14 mRNA and mCD14 and transiently enhanced sCD14 release. A 2-day incubation with LPS caused increases in the levels of CD14 mRNA (2-fold), mCD14 (2-fold), sCD14 (1.5-fold), and LPS-fluorescein isothiocyanate binding (1.5-fold); a 5-h incubation with LPS was sufficient to induce the late effects on mCD14 and sCD14. The maximal effect on mCD14 and sCD14 was reached with > or = 1 ng of LPS per ml; the proportional distribution of the two sCD14 isoforms was not modified by LPS. Besides rough and smooth LPS, lipid A, heat-killed Escherichia coli, lipoteichoic acid, and Staphylococcus aureus cell wall extract (10 micrograms/ml) caused similar increases of mCD14. The LPS effect was blocked by polymyxin B but not by anti-tumor necrosis factor alpha, anti-interleukin-6, anti-gamma interferon, and anti-LPS-binding protein. LPS-induced tumor necrosis factor alpha production was abolished after a second 4-h challenge. In contrast, the LPS-induced increases CD14 mRNA, mCD14, and sCD14 were stronger and appeared earlier after a second LPS challenge. In conclusion, CD14 is transcriptionally upregulated by LPS and other bacterial cell wall constituents.
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Affiliation(s)
- R Landmann
- Department of Research and Internal Medicine, University Hospital, Basel, Switzerland
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Landmann R, Scherer F, Schumann R, Link S, Sansano S, Zimmerli W. LPS directly induces oxygen radical production in human monocytes via LPS binding protein and CD14. J Leukoc Biol 1995; 57:440-9. [PMID: 7533819 DOI: 10.1002/jlb.57.3.440] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In human monocytes, superoxide (O2-) generation accompanies phagocytosis and is important for bactericidal activity. It also contributes to tissue damage in inflammation. In the present study we investigated, whether lipopolysaccharide (LPS) directly stimulates monocyte O2- production with kinetics known for other LPS effects and, if so, by which mechanism. LPS caused a time- and dose-dependent O2- release in nonadherent purified monocytes. The effect appeared after 5 min, peaked at 30 min, and disappeared after 2 h. It was maximal with 10 ng/ml lipid A (+148 +/- 22%, P < .001), 1 ng/ml LPS Escherichia coli Re (+226 +/- 68%, P < .001), and 100 ng/ml LPS Salmonella abortus equi sm (+272 +/- 52%, P < .001), respectively. The effect was not observed in buffer, even when using 10 micrograms/ml LPS. It was dependent on the presence of heat-inactivated AB serum, with a maximal effect at > or = 0.5%. Serum could be replaced by LPS-binding protein (LBP). Polymyxin B and anti-LBP antiserum, respectively, blocked the LPS effect. LPS-induced O2- generation was also completely blocked by anti-CD14 antibodies (3C10 and 63D3) and by their corresponding F(ab')2 fragments. Monocytes treated with phosphoinositol-specific phospholipase C and monocytes from patients with paroxysmal nocturnal hemoglobinuria, lacking the phosphatidylinositol-anchored CD14, did not respond to LPS stimulation with O2- production. Similarly to LPS, E. coli caused stronger O2- production with heat-inactivated serum than without, and this effect was blocked by anti-CD14 antibodies. In conclusion, these data indicate that LPS directly stimulates O2- production in human monocytes via CD14 depending on LBP.
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Affiliation(s)
- R Landmann
- Department of Research, University Hospital, Basel, Switzerland
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Landmann R, Zimmerli W, Sansano S, Link S, Hahn A, Glauser MP, Calandra T. Increased circulating soluble CD14 is associated with high mortality in gram-negative septic shock. J Infect Dis 1995; 171:639-44. [PMID: 7533199 DOI: 10.1093/infdis/171.3.639] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The soluble glycoprotein sCD14 binds lipopolysaccharide, a complex that activates endothelial cells and that may be crucial in gram-negative sepsis. Therefore, serum sCD14 was analyzed in 54 patients with gram-negative septic shock and in 26 healthy controls. sCD14 was tested by ELISA and Western blotting. Patients had higher sCD14 concentrations than controls (median, 3.23 vs. 2.48 micrograms/mL, P = .002). Increased levels were associated with high mortality (median, 4.2 micrograms/mL in nonsurvivors vs. 2.8 micrograms/mL in survivors, P = .001). sCD14 was found in two isoforms (49 and 55 kDa) in monocyte cultures. In sera only one of either form was detectable. Controls had the 49-kDa form, and patients had either the 49- or 55-kDa form, but patients with high levels of sCD14 had only the 55-kDa form. Twenty-one (53%) of 39 with the 55-kDa form and 8 (57%) of 14 with the 49-kDa form died. Thus, the level of sCD14 but not its biochemical form had a prognostic value in patients with gram-negative septic shock.
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Affiliation(s)
- R Landmann
- Department of Research, University Hospital, Basel, Switzerland
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Abstract
The effects of various inotropic interventions on post-rest potentiation and its decay were investigated in isolated cardiac muscle. The inotropic interventions studied were: reduced extracellular Na+ and elevated extracellular Ca2+ concentration; exposure to ouabain, monensin, isoprenaline, phenylephrine and cirazoline. Force of contraction (stimulation frequency 2 Hz) was measured isometrically in left atria and right ventricular strips of rat hearts. Maximum post-rest potentiation was reached after 10 sec. of rest and amounted to 245 +/- 26% of pre-rest control in ventricle and 192 +/- 15% in atria. Ca(2+)-recirculation fraction was calculated from the decay of post-rest potentiation after resumption of regular stimulation, it was 0.77 +/- 0.01 in 11 control ventricular strips. High concentrations of caffeine (3 mmol/l) completely abolished post-rest potentiation in both tissues. The development of post-rest potentiation was accelerated in the presence of most of the inotropic agents. However, with the exception of ouabain and only in atrial muscle, none of the inotropic interventions produced higher post-rest contraction amplitudes than during controls. In rat heart muscle, the inotropic interventions studied are not any more effective in augmenting force of contraction than prolonged stimulation intervals. This suggests that (1) the distribution of Ca2+ into the sarcoplasmic reticulum is at a maximum during post-rest potentiation; (2) modifications of signal transduction pathways cannot further increase post-rest potentiation; and therefore that (3) shifts in Ca2+ distribution act as a limiting factor.
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Affiliation(s)
- U Ravens
- Department of Pharmacology, University of Essen, Germany
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Link S, Erné SN, Edrich J. Finite Element Solution of the Biomagnetic Forward Problem Using Automatically-Constructed Realistic Torso Models. BIOMED ENG-BIOMED TE 1994. [DOI: 10.1515/bmte.1994.39.s1.115] [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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Miller RH, Paape MJ, Filep R, Link S. Flow cytometric analysis of neutrophils in cows' milk. Am J Vet Res 1993; 54:1975-9. [PMID: 8116925] [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: 01/28/2023]
Abstract
Procedures were developed to count neutrophils in milk, using a flow cytometer. Milk samples from 2 experiments were counted: 1 with 4 noninfected cows and a second with 5 noninfected cows that were injected with endotoxin in 2 mammary quarters. Thus, the procedures were evaluated on normal milk and on that with high somatic cell count. Flow cytometric procedures involved fluorescence detection (from the dye carboxydimethylfluorescein diacetate) to distinguish intact and viable from fragmented cells, forward light scatter to detect cell size differences, and right-angle side scatter to detect cellular granularity. High fluorescence, large size, and high degree of granularity identified viable neutrophils. For all samples, neutrophils were also counted manually, using the cytologic centrifugation approach to create the slides; manual counts were used as the standard for comparison. In experiment 1 (normal milk), mean values for percentage of viable neutrophils estimated by manual and flow cytometry procedures agreed closely (26% vs 25.8% for foremilk and 28.8% vs 26.6% for bucket milk). Sources of variation in manual and flow cytometric estimates of percentage of neutrophils were examined. Cow variation was significant (P < 0.01) for manual and flow cytometric counts, but was larger for flow cytometric counts. Day-to-day variation in counts on milk from the same cow was negligible for manual counts, but was significant (P < 0.01) for flow cytometric counts.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R H Miller
- Milk Secretion and Mastitis Laboratory, USDA, Beltsville, MD 20705
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Link S, Friedburg DZ, Wood BP. Radiological cases of the month. Pulmonary sling anomaly of the left pulmonary artery. Am J Dis Child 1993; 147:685-6. [PMID: 8506841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S Link
- Department of Radiology, Medical College of Wisconsin, Milwaukee
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48
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Abstract
This paper presents the results of a survey of 43 occupational therapy academic programs regarding their preparation of students to work with young children with special needs. The number of instructional hours devoted to topics related to services for infants or toddlers and their families varied greatly. Some programs plan an increase in hours but are limited by the total hours available within the curriculum. This paper also shares the recommendations of a panel of occupational therapists with expertise in early intervention and entry-level education. The panel was concerned with the quality of preparation of therapists entering early intervention programs and encouraged the profession to review the amount of course work within each curriculum that introduces students to basic knowledge and skills related to early intervention. Some knowledge, such as the consultant's role and working with families of persons who are physically or mentally challenged, are common to other practice areas. The panel stressed that students be taught strategies for obtaining the training necessary for postgraduate entry into a specialty area such as early intervention.
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Affiliation(s)
- R Humphry
- Division of Occupational Therapy, University of North Carolina, Chapel Hill 27599-7120
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Abstract
A rapidly proliferating T-cell line, HCD8, was derived from the peripheral blood lymphocytes of an apparently healthy individual during the course of a T-cell cloning experiment. This T-cell line expressed a very unusual phenotype: CD1+, CD2-, CD3+ (cytoplasmic), CD4-, CD5+, CD7+, CD8-, interleukin-2 receptor (IL-2 R) (p55)-, and T-cell antigen receptor (TCAR) alpha beta-. Assays for reverse transcriptase activity and for human T-lymphotropic retroviral sequences in the cellular DNA were negative, indicating that the cells were not transformed by human T-lymphotropic virus (HTLV)-I, HTLV-II, or human immunodeficiency virus (HIV)-I. Culturing the cells in the differentiation inducing agent 12-O-tetradecanoyl phorbol 13-acetate induced an increased expression of CD3 but no other significant changes in T-cell markers. A small population of CD4-negative and CD8-negative T-lymphocytes exist in human peripheral blood and they exhibit natural killer (NK) and antibody-dependent cell-mediated cytotoxic (ADCC) activity. However, the authors' cell line failed to demonstrate such cytotoxic function. The TCAR gene rearrangement studies showed that both T gamma genes were rearranged while the T beta genes were in the germ line configuration and the T delta genes were deleted. HCD8 strongly expressed the antigens Leu M1 and Ki-1, markers detected only rarely on normal unstimulated human T-cells, but quite consistently found on Reed-Sternberg cells and cells of some large pleomorphic T-cell lymphomas. HCD8 may be used to study the control of Leu M1 and Ki-1 expression in T-cells and it may provide some insight into the cellular origin of the above-mentioned lymphomas.
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Affiliation(s)
- W C Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
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Nienartowicz A, Link S, Moll W. Adaptation of the uterine arcade in rats to pregnancy. J Dev Physiol 1989; 12:101-8. [PMID: 2621336] [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: 01/01/2023]
Abstract
In order to study the adaptation of the uterine arterial system to pregnancy we measured vascular dimensions and other growth related data (DNA content and [3H]thymidine incorporation rate) on excised uterine arcades, pressurized to 100 mmHg, of rats before and during pregnancy (day 8, 18 and 21 of gestation). The vascular conductance of the arcade was calculated using a numerical method. In order to investigate the response of the arcade to flow impairment during early pregnancy, the same measurements were repeated on uterine arcades from pregnant animals (day 21 of gestation), where the left uterine artery had been ligated on day 8 of pregnancy. In adult virgin rats, the uterine arcade was 0.3 +/- 0.05 mm wide and 50 +/- 5 mm long. With these vascular dimensions the vascular conductance of the arcade (2.5 microliters/(s x mmHg] was calculated to be inadequate for the blood supply to the pregnant uterus at term. During the course of pregnancy modest changes were seen: The arcade increased 80% in length, 30% and 80% in internal diameter at the ovarian and cervical origin respectively and 6 times in conductance. Weight of the arcades increased 2-3-fold, [3H]thymidine incorporation rate 7-fold whereas the DNA mass remained constant. Ligation of the uterine artery on day 8 caused a 2 times increase in internal diameter of the ovarian (open) origin of the arcade without change in weight, whilst the cervical (ligated) origin of the arcade had the same internal diameter as that of the control group. The calculated vascular conductance of the ligated arcade was the same as for controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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