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Merle T, Theis S, Kamgoué A, Martin E, Sarron F, Gay G, Farge E, Suzanne M. DISSECT is a tool to segment and explore cell and tissue mechanics in highly deformed 3D epithelia. Dev Cell 2023; 58:2181-2193.e4. [PMID: 37586367 DOI: 10.1016/j.devcel.2023.07.017] [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: 07/07/2022] [Revised: 03/17/2023] [Accepted: 07/24/2023] [Indexed: 08/18/2023]
Abstract
Understanding morphogenesis strongly relies on the characterization of tissue topology and mechanical properties deduced from imaging data. The development of new imaging techniques offers the possibility to go beyond the analysis of mostly flat surfaces and image and analyze complex tissue organization in depth. An important bottleneck in this field is the need to analyze imaging datasets and extract quantifications not only of cell and tissue morphology but also of the cytoskeletal network's organization in an automatized way. Here, we describe a method, called DISSECT, for DisPerSE (Discrete Persistent Structure Extractor)-based Segmentation and Exploration of Cells and Tissues, that offers the opportunity to extract automatically, in strongly deformed epithelia, a precise characterization of the spatial organization of a given cytoskeletal network combined with morphological quantifications in highly remodeled three-dimensional (3D) epithelial tissues. We believe that this method, applied here to Drosophila tissues, will be of general interest in the expanding field of morphogenesis and tissue biomechanics.
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Affiliation(s)
- Tatiana Merle
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
| | - Sophie Theis
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Alain Kamgoué
- Image Processing Facility, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Emmanuel Martin
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Florian Sarron
- IRAP, Institut de Recherche en Astrophysique et Planétologie, CNRS, 14 avenue E. Belin, 31400, Toulouse, France; Université de Toulouse, CNES, UPS-OMP, 14 avenue E. Belin, 31400 Toulouse, France
| | - Guillaume Gay
- Aix Marseille Université, Mutli-Engineering Platform, CENTURI, Marseille, France
| | - Emmanuel Farge
- Mechanics and Genetics of Embryonic Development group, Institut Curie, PSL Research University, CNRS, UMR168, Inserm, Marie Curie UnivParis 06, Institut Curie, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Magali Suzanne
- Molecular, Cellular and Developmental Biology unit (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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2
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Chevalier X, Correia CG, Pound-Lana G, Bézard P, Sérégé M, Petit-Etienne C, Gay G, Cunge G, Cabannes-Boué B, Nicolet C, Navarro C, Cayrefourcq I, Müller M, Hadziioannou G, Iliopoulos I, Fleury G, Zelsmann M. Multifunctional Top-Coats Strategy for DSA of High-χ Block Copolymers. J PHOTOPOLYM SCI TEC 2021. [DOI: 10.2494/photopolymer.34.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Marcus Müller
- Georg-August Universität Göttingen, Institute for Theoretical Physics
| | | | - Ilias Iliopoulos
- Laboratoire PIMM, Arts et Métiers Institute of Technology, CNRS, Cnam, HESAM Université
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3
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de Lafontaine M, Pargon E, Gay G, Petit-Etienne C, David S, Barnes JP, Rochat N, Jaouad A, Volatier M, Fafard S, Aimez V, Darnon M. Anisotropic and low damage III-V/Ge heterostructure etching for multijunction solar cell fabrication with passivated sidewalls. Micro and Nano Engineering 2021. [DOI: 10.1016/j.mne.2021.100083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Chevalier X, Gomes Correia C, Pound-Lana G, Bézard P, Sérégé M, Petit-Etienne C, Gay G, Cunge G, Cabannes-Boué B, Nicolet C, Navarro C, Cayrefourcq I, Müller M, Hadziioannou G, Iliopoulos I, Fleury G, Zelsmann M. Lithographically Defined Cross-Linkable Top Coats for Nanomanufacturing with High-χ Block Copolymers. ACS Appl Mater Interfaces 2021; 13:11224-11236. [PMID: 33621463 DOI: 10.1021/acsami.1c00694] [Citation(s) in RCA: 9] [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] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The directed self-assembly (DSA) of block copolymers (BCPs) is a powerful method for the manufacture of high-resolution features. Critical issues remain to be addressed for successful implementation of DSA, such as dewetting and controlled orientation of BCP domains through physicochemical manipulations at the BCP interfaces, and the spatial positioning and registration of the BCP features. Here, we introduce novel top-coat (TC) materials designed to undergo cross-linking reactions triggered by thermal or photoactivation processes. The cross-linked TC layer with adjusted composition induces a mechanical confinement of the BCP layer, suppressing its dewetting while promoting perpendicular orientation of BCP domains. The selection of areas of interest with perpendicular features is performed directly on the patternable TC layer via a lithography step and leverages attractive integration pathways for the generation of locally controlled BCP patterns and nanostructured BCP multilayers.
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Affiliation(s)
- Xavier Chevalier
- ARKEMA FRANCE, GRL, Route Nationale 117, BP34 64170 Lacq, France
| | - Cindy Gomes Correia
- University of Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600 Pessac, France
| | - Gwenaelle Pound-Lana
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | - Philippe Bézard
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | - Matthieu Sérégé
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | - Camille Petit-Etienne
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | - Guillaume Gay
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | - Gilles Cunge
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
| | | | - Célia Nicolet
- ARKEMA FRANCE, GRL, Route Nationale 117, BP34 64170 Lacq, France
| | | | - Ian Cayrefourcq
- ARKEMA FRANCE, GRL, Route Nationale 117, BP34 64170 Lacq, France
| | - Marcus Müller
- Georg-August Universität Göttingen, Institute for Theoretical Physics, 37077 Göttingen, Germany
| | - Georges Hadziioannou
- University of Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600 Pessac, France
| | - Ilias Iliopoulos
- Laboratoire PIMM, Arts et Métiers Institute of Technology, CNRS, Cnam, HESAM Université, 151 Boulevard de l'Hôpital, 75013 Paris, France
| | - Guillaume Fleury
- University of Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600 Pessac, France
| | - Marc Zelsmann
- University of Grenoble Alpes, CNRS, CEA/LETI Minatec, Grenoble INP, LTM, 38000 Grenoble, France
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Martin E, Theis S, Gay G, Monier B, Rouvière C, Suzanne M. Arp2/3-dependent mechanical control of morphogenetic robustness in an inherently challenging environment. Dev Cell 2021; 56:687-701.e7. [PMID: 33535069 PMCID: PMC7955168 DOI: 10.1016/j.devcel.2021.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 10/23/2020] [Accepted: 01/08/2021] [Indexed: 12/21/2022]
Abstract
Epithelial sheets undergo highly reproducible remodeling to shape organs. This stereotyped morphogenesis depends on a well-defined sequence of events leading to the regionalized expression of developmental patterning genes that finally triggers downstream mechanical forces to drive tissue remodeling at a pre-defined position. However, how tissue mechanics controls morphogenetic robustness when challenged by intrinsic perturbations in close proximity has never been addressed. Using Drosophila developing leg, we show that a bias in force propagation ensures stereotyped morphogenesis despite the presence of mechanical noise in the environment. We found that knockdown of the Arp2/3 complex member Arpc5 specifically affects fold directionality while altering neither the developmental nor the force generation patterns. By combining in silico modeling, biophysical tools, and ad hoc genetic tools, our data reveal that junctional myosin II planar polarity favors long-range force channeling and ensures folding robustness, avoiding force scattering and thus isolating the fold domain from surrounding mechanical perturbations. Drosophila developing leg folding is extremely robust Fold orientation becomes variable in Arp2/3 knockdown condition Arp2/3 controls junctional myosin II planar polarity Myosin II planar polarity ensures fold robustness through force channeling
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Affiliation(s)
- Emmanuel Martin
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Sophie Theis
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France; Morphogénie Logiciels, 32110 St Martin d'Armagnac, France
| | - Guillaume Gay
- Morphogénie Logiciels, 32110 St Martin d'Armagnac, France; Turing Center For Living Systems, Aix-MarseilleUniversity, 13009, Marseille, France.
| | - Bruno Monier
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France
| | - Christian Rouvière
- Image Processing Facility, Center of Integrative Biology (CBI), Université de Toulouse, CNRS, UPS, France
| | - Magali Suzanne
- Molecular, Cellular & Developmental Biology (MCD), Center of Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, France.
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Gracia M, Theis S, Proag A, Gay G, Benassayag C, Suzanne M. Mechanical impact of epithelial-mesenchymal transition on epithelial morphogenesis in Drosophila. Nat Commun 2019; 10:2951. [PMID: 31273212 PMCID: PMC6609679 DOI: 10.1038/s41467-019-10720-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/28/2019] [Indexed: 12/20/2022] Open
Abstract
Epithelial-mesenchymal transition (EMT) is an essential process both in physiological and pathological contexts. Intriguingly, EMT is often associated with tissue invagination during development; however, the impact of EMT on tissue remodeling remain unexplored. Here, we show that at the initiation of the EMT process, cells produce an apico-basal force, orthogonal to the surface of the epithelium, that constitutes an important driving force for tissue invagination in Drosophila. When EMT is ectopically induced, cells starting their delamination generate an orthogonal force and induce ectopic folding. Similarly, during mesoderm invagination, cells undergoing EMT generate an apico-basal force through the formation of apico-basal structures of myosin II. Using both laser microdissection and in silico physical modelling, we show that mesoderm invagination does not proceed if apico-basal forces are impaired, indicating that they constitute driving forces in the folding process. Altogether, these data reveal the mechanical impact of EMT on morphogenesis.
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Affiliation(s)
- Mélanie Gracia
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Sophie Theis
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.,Morphogénie Logiciels, 32110, St Martin d'Armagnac, France
| | - Amsha Proag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France
| | - Guillaume Gay
- Morphogénie Logiciels, 32110, St Martin d'Armagnac, France.
| | - Corinne Benassayag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, 31062, France.
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7
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Partier A, Gay G, Tassy C, Beckert M, Feuillet C, Barret P. Molecular and FISH analyses of a 53-kbp intact DNA fragment inserted by biolistics in wheat (Triticum aestivum L.) genome. Plant Cell Rep 2017; 36:1547-1559. [PMID: 28667403 DOI: 10.1007/s00299-017-2173-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
A large, 53-kbp, intact DNA fragment was inserted into the wheat ( Triticum aestivum L.) genome. FISH analyses of individual transgenic events revealed multiple insertions of intact fragments. Transferring large intact DNA fragments containing clusters of resistance genes or complete metabolic pathways into the wheat genome remains a challenge. In a previous work, we showed that the use of dephosphorylated cassettes for wheat transformation enabled the production of simple integration patterns. Here, we used the same technology to produce a cassette containing a 44-kb Arabidopsis thaliana BAC, flanked by one selection gene and one reporter gene. This 53-kb linear cassette was integrated in the bread wheat (Triticum aestivum L.) genome by biolistic transformation. Our results showed that transgenic plants harboring the entire cassette were generated. The inheritability of the cassette was demonstrated in the T1 and T2 generation. Surprisingly, FISH analysis performed on T1 progeny of independent events identified double genomic insertions of intact fragments in non-homoeologous positions. Inheritability of these double insertions was demonstrated by FISH analysis of the T1 generation. Relative conclusions that can be drawn from molecular or FISH analysis are discussed along with future prospects of the engineering of large fragments for wheat transformation or genome editing.
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Affiliation(s)
- A Partier
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France
| | - G Gay
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France
| | - C Tassy
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France
| | - M Beckert
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France
| | - C Feuillet
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France
| | - P Barret
- Unité Mixte de Recherche 1095-Institut National de la Recherche Agronomique-Génétique, Diversité et Écophysiologie des Céréales, Domaine de Crouël, 63039, Clermont-Ferrand Cedex 2, France.
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Coton T, Sbai W, Beaussac M, Luciano L, Gay G, Garnotel E. New flexible endoscopes: Surprising bacterial colonization post-disinfection. Clin Res Hepatol Gastroenterol 2017; 41:e63-e64. [PMID: 28579002 DOI: 10.1016/j.clinre.2017.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/05/2017] [Indexed: 02/04/2023]
Affiliation(s)
- T Coton
- Digestive pathology unit, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France.
| | - W Sbai
- Digestive pathology unit, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France
| | - M Beaussac
- Digestive pathology unit, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France
| | - L Luciano
- Digestive pathology unit, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France
| | - G Gay
- Biomedical engineering unit, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France
| | - E Garnotel
- Bacteriological laboratory, military teaching hospital Laveran, CS 50004, 13384 Marseille cedex 13, France
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Defrance F, Casaletti M, Sarrazin J, Wiedner MC, Gibson H, Gay G, Lefèvre R, Delorme Y. Structured surface reflector design for oblique incidence beam splitter at 610 GHz. Opt Express 2016; 24:20335-20345. [PMID: 27607640 DOI: 10.1364/oe.24.020335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An iterative alternate projection-based algorithm is developed to design structured surface reflectors to operate as beam splitters at GHz and THz frequencies. To validate the method, a surface profile is determined to achieve a reflector at 610 GHz that generates four equal-intensity beams towards desired directions of ±12.6° with respect to the specular reflection axis. A prototype is fabricated and the beam splitter behavior is experimentally demonstrated. Measurements confirm a good agreement (within 1%) with computer simulations using Feko, validating the method. The beam splitter at 610 GHz has a measured efficiency of 78% under oblique incidence illumination that ensures a similar intensity between the four reflected beams (variation of about 1%).
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Combedazou A, Choesmel-Cadamuro V, Gay G, Liu J, Dupré L, Ramel D, Wang X. Myosin II governs collective cell migration behaviour downstream of guidance receptor signalling. J Cell Sci 2016; 130:97-103. [PMID: 27034137 DOI: 10.1242/jcs.179952] [Citation(s) in RCA: 24] [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] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 03/18/2016] [Indexed: 02/04/2023] Open
Abstract
Border cell migration during Drosophila oogenesis is a potent model to study collective cell migration, a process involved in development and metastasis. Border cell clusters adopt two main types of behaviour during migration: linear and rotational. However, the molecular mechanism controlling the switch from one to the other is unknown. Here, we demonstrate that non-muscle Myosin II (NMII, also known as Spaghetti squash) activity controls the linear-to-rotational switch. Furthermore, we show that the regulation of NMII takes place downstream of guidance receptor signalling and is critical to ensure efficient collective migration. This study thus provides new insight into the molecular mechanism coordinating the different cell behaviours in a migrating cluster.
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Affiliation(s)
- Anne Combedazou
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Valérie Choesmel-Cadamuro
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Guillaume Gay
- DamCB, Data Analysis and Modelling for Cell Biology, Marseille F-13005, France
| | - Jiaying Liu
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Loïc Dupré
- INSERM, UMR 1043, Centre de Physiopathologie de Toulouse Purpan, 31024 Toulouse, France.,Université Toulouse III Paul-Sabatier, 31062 Toulouse, France.,CNRS, UMR 5282, 31204 Toulouse, France
| | - Damien Ramel
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Xiaobo Wang
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
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Mary H, Gay G, Courthéoux T, Fouchard J, Céline R, Tournier S, Gachet Y. Building an Accurate Chromosome Segregation Machine in Fission Yeast. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2550] [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: 10/22/2022] Open
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Mary H, Fouchard J, Gay G, Reyes C, Gauthier T, Gruget C, Pécréaux J, Tournier S, Gachet Y. Fission yeast kinesin-8 controls chromosome congression independently of oscillations. J Cell Sci 2015; 128:3720-30. [PMID: 26359299 PMCID: PMC4631777 DOI: 10.1242/jcs.160465] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [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: 07/24/2014] [Accepted: 09/03/2015] [Indexed: 01/09/2023] Open
Abstract
In higher eukaryotes, efficient chromosome congression relies, among other players, on the activity of chromokinesins. Here, we provide a quantitative analysis of kinetochore oscillations and positioning in Schizosaccharomyces pombe, a model organism lacking chromokinesins. In wild-type cells, chromosomes align during prophase and, while oscillating, maintain this alignment throughout metaphase. Chromosome oscillations are dispensable both for kinetochore congression and stable kinetochore alignment during metaphase. In higher eukaryotes, kinesin-8 family members control chromosome congression by regulating their oscillations. By contrast, here, we demonstrate that fission yeast kinesin-8 controls chromosome congression by an alternative mechanism. We propose that kinesin-8 aligns chromosomes by controlling pulling forces in a length-dependent manner. A coarse-grained model of chromosome segregation implemented with a length-dependent process that controls the force at kinetochores is necessary and sufficient to mimic kinetochore alignment, and prevents the appearance of lagging chromosomes. Taken together, these data illustrate how the local action of a motor protein at kinetochores provides spatial cues within the spindle to align chromosomes and to prevent aneuploidy. Highlighted Article: Quantitative analysis in S. pombe reveals that chromosome oscillations are dispensable for kinetochore congression in mitosis. Kinesin-8 controls chromosome congression through length-dependent pulling forces.
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Affiliation(s)
- Hadrien Mary
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Jonathan Fouchard
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Guillaume Gay
- DAMCB, 43 rue Horace Bertin, Marseille 13005, France
| | - Céline Reyes
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Tiphaine Gauthier
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Clémence Gruget
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Jacques Pécréaux
- IGDR, Institute of Genetics and Development of Rennes, University Rennes 1, Rennes F-35043, France
| | - Sylvie Tournier
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
| | - Yannick Gachet
- Université de Toulouse, LBCMCP, 118 route de Narbonne, Toulouse F-31062, France CNRS, LBCMCP-UMR5088, Toulouse F-31062, France
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Lim R, Chen C, Naidoo N, Gay G, Tang W, Seah D, Chen R, Tan N, Lee J, Tai E, Chia K, Lim W. Anthropometrics indices of obesity, and all-cause and cardiovascular disease-related mortality, in an Asian cohort with type 2 diabetes mellitus. Diabetes & Metabolism 2015; 41:291-300. [DOI: 10.1016/j.diabet.2014.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 12/02/2014] [Accepted: 12/07/2014] [Indexed: 10/24/2022]
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Monier B, Gettings M, Gay G, Mangeat T, Schott S, Guarner A, Suzanne M. [The last surge of dying cells, a key stage during the tissular morphogenesis]. Med Sci (Paris) 2015; 31:475-7. [PMID: 26059294 DOI: 10.1051/medsci/20153105005] [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: 11/15/2022] Open
Affiliation(s)
- Bruno Monier
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Melanie Gettings
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Guillaume Gay
- DamCB, Data Analysis and Modelling for Cell Biology, 13005 Marseille, France
| | - Thomas Mangeat
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Sonia Schott
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
| | - Ana Guarner
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049 Madrid, Espagne
| | - Magali Suzanne
- Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France - CNRS, LBCMCP, F-31062 Toulouse, France
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15
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Monier B, Gettings M, Gay G, Mangeat T, Schott S, Guarner A, Suzanne M. Apico-basal forces exerted by apoptotic cells drive epithelium folding. Nature 2015; 518:245-8. [PMID: 25607361 DOI: 10.1038/nature14152] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/09/2014] [Indexed: 12/29/2022]
Abstract
Epithelium folding is a basic morphogenetic event that is essential in transforming simple two-dimensional epithelial sheets into three-dimensional structures in both vertebrates and invertebrates. Folding has been shown to rely on apical constriction. The resulting cell-shape changes depend either on adherens junction basal shift or on a redistribution of myosin II, which could be driven by mechanical signals. Yet the initial cellular mechanisms that trigger and coordinate cell remodelling remain largely unknown. Here we unravel the active role of apoptotic cells in initiating morphogenesis, thus revealing a novel mechanism of epithelium folding. We show that, in a live developing tissue, apoptotic cells exert a transient pulling force upon the apical surface of the epithelium through a highly dynamic apico-basal myosin II cable. The apoptotic cells then induce a non-autonomous increase in tissue tension together with cortical myosin II apical stabilization in the surrounding tissue, eventually resulting in epithelium folding. Together our results, supported by a theoretical biophysical three-dimensional model, identify an apoptotic myosin-II-dependent signal as the initial signal leading to cell reorganization and tissue folding. This work further reveals that, far from being passively eliminated as generally assumed (for example, during digit individualization), apoptotic cells actively influence their surroundings and trigger tissue remodelling through regulation of tissue tension.
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Affiliation(s)
- Bruno Monier
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Melanie Gettings
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Guillaume Gay
- DamCB, Data Analysis and Modelling for Cell Biology, 13005 Marseille, France
| | - Thomas Mangeat
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Sonia Schott
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
| | - Ana Guarner
- Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049 Madrid, Spain
| | - Magali Suzanne
- 1] Université de Toulouse, UPS, LBCMCP, F-31062 Toulouse, France [2] CNRS, LBCMCP, F-31062 Toulouse, France
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Abstract
Endoscopic submucosal dissection (ESD) was developed in Japan but has now also become permanently established in various centers in Europe. ESD is an endoscopic en bloc mucosal resection technique for the treatment of early cancers with a diameter >1 cm and also superficial precancerous lesions, which could only be removed unsatisfactorily in several fragments or with uncertain lateral safety margins using previous loop excision procedures. Using ESD a lesion is excised after circular marking and generous submucosal injection with a safety margin of approximately 5 mm and subsequently resected at the level of the submucosa with a 1-3 mm short diathermic knife. ESD requires high technical skills in interventional endoscopy and is more time-consuming than snare resection techniques. However, numerous studies have shown a clear superiority for ESD with respect to the R0 resection rate and the local recurrence rate. The present article gives a current review of the use of ESD in the upper and lower gastrointestinal tract and demonstrates perspectives of the procedure.
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Affiliation(s)
- J Hochberger
- Sérvice de Gastroentérologie, Hôpitaux Universitaires de Strasbourg - NHC, 1 Place de l'Hôpital, 67000, Strasbourg (Cedex), Frankreich.
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17
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Tallegas S, Baron T, Gay G, Aggrafeil C, Salhi B, Chevolleau T, Cunge G, Bsiesy A, Tiron R, Chevalier X, Navarro C, Aissou K, Otsuka I, Halila S, Fort S, Borsali R. Block copolymer technology applied to nanoelectronics. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pssc.201300002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Spada C, Hassan C, Galmiche J, Neuhaus H, Dumonceau J, Adler S, Epstein O, Gay G, Pennazio M, Rex D, Benamouzig R, de Franchis R, Delvaux M, Devière J, Eliakim R, Fraser C, Hagenmuller F, Herrerias J, Keuchel M, Macrae F, Munoz-Navas M, Ponchon T, Quintero E, Riccioni M, Rondonotti E, Marmo R, Sung J, Tajiri H, Toth E, Triantafyllou K, Van Gossum A, Costamagna G. Kolonkapselendoskopie: Leitlinie der Europäischen Gesellschaft für Gastrointestinale Endoskopie. Endo heute 2012; 25:145-154. [DOI: 10.1055/s-0032-1312968] [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] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
- C. Spada
- Digestive Endoscopy Unit, Catholic University, Rome, Italy
| | - C. Hassan
- Department of Gastroenterology and Hepatology, Nantes, University, Nantes, France
| | - J. Galmiche
- Department of Gastroenterology, Evangelisches Krankenhaus, Düsseldorf, Germany
| | - H. Neuhaus
- Service of Gastroenterology and Hepatology, Geneva University Hospitals, Geneva, Switzerland
| | - J. Dumonceau
- Department of Gastroenterology, Bikur Holim Hospital; Jerusalem, Israel
| | - S. Adler
- Department of Gastroenterology, Royal Free and University College Medical School, London, UK
| | - O. Epstein
- Department of Hepato-Gastroenterology, HU Strasbourg, Strasbourg, France
| | - G. Gay
- Division of Gastroenterology 2, San Giovanni Battista University Teaching Hospital, Turin, Italy
| | - M. Pennazio
- Department of Gastroenterology, Indiana University Hospital, Indianapolis, USA
| | - D. Rex
- Department of Gastroenterology, Avienne Hospital, University of Paris, Bobigny, France
| | - R. Benamouzig
- Gastroenterology Unit, Luigi Sacco University Hospital, Milan, Italy
| | - R. de Franchis
- Department of Gastroenterology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - M. Delvaux
- Chaim Sheba Medical Center, Tel-Aviv, Israel
| | - J. Devière
- Department of Gastroenterology, St. Mark's Hospital, London, UK
| | - R. Eliakim
- Department of Medicine I, Altona General Hospital, Hamburg, Germany
| | - C. Fraser
- Gastroenterology Service, Virgen Macarena University Hospital, Seville, Spain
| | - F. Hagenmuller
- Clinic for Internal Medicine, Bethesda Krankenhaus Bergedorf, Hamburg, Germany
| | - J. Herrerias
- Department of Gastroenterology and Clinical Nutrition Service, Royal Melbourne Hospital, Melbourne, Australia
| | - M. Keuchel
- Digestive Endoscopy Unit, Clinica Universitaria de Navarra, Pamplona, Spain
| | - F. Macrae
- Department of Gastroenterology, Hospital Edouard Herriot, Lyon, France
| | - M. Munoz-Navas
- Department of Gastroenterology, Hospital Universitario de Canarias, Tenerife, Spain
| | - T. Ponchon
- Gastroenterology Unit, Ospedale Valdue, Como, Italy
| | - E. Quintero
- Division of Gastroenterology, Curto Hospital, Polla, Italy
| | - M. Riccioni
- Department of Medicine and Therapeutics, Division of Gastroenterology, Prince of Wales Hospital, Shatin, N.T, Hong Kong
| | - E. Rondonotti
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - R. Marmo
- Endoscopy Unit, Skane University Hospital, Lund University, Malmö, Sweden
| | - J. Sung
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
| | - H. Tajiri
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
| | - E. Toth
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
| | - K. Triantafyllou
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
| | - A. Van Gossum
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
| | - G. Costamagna
- Hepatogastroenterology Unit, 2nd department of Internal Medicine-Propaedeutic, Attikon University General Hospital, Athens University, Athens, Greece
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Spada C, Hassan C, Galmiche JP, Neuhaus H, Dumonceau JM, Adler S, Epstein O, Gay G, Pennazio M, Rex DK, Benamouzig R, de Franchis R, Delvaux M, Devière J, Eliakim R, Fraser C, Hagenmuller F, Herrerias JM, Keuchel M, Macrae F, Munoz-Navas M, Ponchon T, Quintero E, Riccioni ME, Rondonotti E, Marmo R, Sung JJ, Tajiri H, Toth E, Triantafyllou K, Van Gossum A, Costamagna G. Colon capsule endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy 2012; 44:527-36. [PMID: 22389230 DOI: 10.1055/s-0031-1291717] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [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: 02/07/2023]
Abstract
PillCam colon capsule endoscopy (CCE) is an innovative noninvasive, and painless ingestible capsule technique that allows exploration of the colon without the need for sedation and gas insufflation. Although it is already available in European and other countries, the clinical indications for CCE as well as the reporting and work-up of detected findings have not yet been standardized. The aim of this evidence-based and consensus-based guideline, commissioned by the European Society of Gastrointestinal Endoscopy (ESGE) is to furnish healthcare providers with a comprehensive framework for potential implementation of this technique in a clinical setting.
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Affiliation(s)
- C Spada
- Digestive Endoscopy Unit, Catholic University, Rome, Italy.
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20
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Gay G, Courtheoux T, Reyes C, Tournier S, Gachet Y. A stochastic model of kinetochore-microtubule attachment accurately describes fission yeast chromosome segregation. ACTA ACUST UNITED AC 2012; 196:757-74. [PMID: 22412019 PMCID: PMC3308688 DOI: 10.1083/jcb.201107124] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In fission yeast, erroneous attachments of spindle microtubules to kinetochores are frequent in early mitosis. Most are corrected before anaphase onset by a mechanism involving the protein kinase Aurora B, which destabilizes kinetochore microtubules (ktMTs) in the absence of tension between sister chromatids. In this paper, we describe a minimal mathematical model of fission yeast chromosome segregation based on the stochastic attachment and detachment of ktMTs. The model accurately reproduces the timing of correct chromosome biorientation and segregation seen in fission yeast. Prevention of attachment defects requires both appropriate kinetochore orientation and an Aurora B-like activity. The model also reproduces abnormal chromosome segregation behavior (caused by, for example, inhibition of Aurora B). It predicts that, in metaphase, merotelic attachment is prevented by a kinetochore orientation effect and corrected by an Aurora B-like activity, whereas in anaphase, it is corrected through unbalanced forces applied to the kinetochore. These unbalanced forces are sufficient to prevent aneuploidy.
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Affiliation(s)
- Guillaume Gay
- Laboratoire de biologie cellulaire et moléculaire du contrôle de la proliferation, Université de Toulouse, F-31062 Toulouse, France
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Lorenzo C, Frongia C, Jorand R, Fehrenbach J, Weiss P, Maandhui A, Gay G, Ducommun B, Lobjois V. Live cell division dynamics monitoring in 3D large spheroid tumor models using light sheet microscopy. Cell Div 2011; 6:22. [PMID: 22152157 PMCID: PMC3274476 DOI: 10.1186/1747-1028-6-22] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/12/2011] [Indexed: 11/10/2022] Open
Abstract
Background Multicellular tumor spheroids are models of increasing interest for cancer and cell biology studies. They allow considering cellular interactions in exploring cell cycle and cell division mechanisms. However, 3D imaging of cell division in living spheroids is technically challenging and has never been reported. Results Here, we report a major breakthrough based on the engineering of multicellular tumor spheroids expressing an histone H2B fluorescent nuclear reporter protein, and specifically designed sample holders to monitor live cell division dynamics in 3D large spheroids using an home-made selective-plane illumination microscope. Conclusions As illustrated using the antimitotic drug, paclitaxel, this technological advance paves the way for studies of the dynamics of cell divion processes in 3D and more generally for the investigation of tumor cell population biology in integrated system as the spheroid model.
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Affiliation(s)
- Corinne Lorenzo
- Université de Toulouse; ITAV-UMS3039, F-31106 Toulouse, France.
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Abstract
This review reports the highlights of the first International Conference on Capsule and Double-Balloon Endoscopy, held in Paris (27 - 28 August 2010), under the chairmanship of Professor G. Gay (Nancy, France). The conference was devoted to the technical issues and clinical experience related to capsule endoscopy and double-balloon endoscopy (DBE), techniques that have been developed over the past decade for the endoscopic investigation of intestinal diseases. The conference focused on the technical advances of new-generation endoscopes and capsules and the clinical experience gained with capsule endoscopy and DBE. Important advances in the knowledge of obscure gastrointestinal bleeding, inflammatory bowel diseases, and celiac disease were also discussed. The second part of the conference was mainly devoted to the investigation of the colon and discussed the technical issues and results of initial controlled studies of the colonic capsule vs. conventional colonoscopy. In addition, the clinical usefulness of double colonoscopy was demonstrated in patients with previously failed colonoscopy. Finally, the role of DBE was discussed with respect to the investigation and treatment of patients with surgically modified anatomy. The conference was attended by 750 delegates and presented a unique opportunity for an in-depth review of the current knowledge in the field and to ascertain/determine the main lines for the future developments of capsule endoscopy and DBE.
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Affiliation(s)
- M Delvaux
- Internal Medicine and Digestive Pathology, CHU de Nancy, France.
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23
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Gay G, Baron T, Agraffeil C, Salhi B, Chevolleau T, Cunge G, Grampeix H, Tortai JH, Martin F, Jalaguier E, De Salvo B. CMOS compatible strategy based on selective atomic layer deposition of a hard mask for transferring block copolymer lithography patterns. Nanotechnology 2010; 21:435301. [PMID: 20876979 DOI: 10.1088/0957-4484/21/43/435301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A generic, CMOS compatible strategy for transferring a block copolymer template to a semiconductor substrate is demonstrated. An aluminum oxide (Al(2)O(3)) hard mask is selectively deposited by atomic layer deposition in an organized array of holes obtained in a PS matrix via PS-b-PMMA self-assembly. The Al(2)O(3) nanodots act as a highly resistant mask to plasma etching, and are used to pattern high aspect ratio (>10) silicon nanowires and nanopillars.
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Affiliation(s)
- G Gay
- CEA LETI MINATEC, Grenoble, France.
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Abstract
The tug of war that ensues when a kinetochore binds microtubules from both spindle poles is resolved by Ase1/Prc1. Faithful segregation of sister chromatids requires the attachment of each kinetochore (Kt) to microtubules (MTs) that extend from opposite spindle poles. Merotelic Kt orientation is a Kt–MT misattachment in which a single Kt binds MTs from both spindle poles rather than just one. Genetic induction of merotelic Kt attachment during anaphase in fission yeast resulted in intra-Kt stretching followed by either correction or Kt disruption. Laser ablation of spindle MTs revealed that intra-Kt stretching and merotelic correction were dependent on MT forces. The presence of multiple merotelic chromosomes linearly antagonized the spindle elongation rate, and this phenomenon could be solved numerically using a simple force balance model. Based on the predictions of our mechanical model, we provide in vivo evidence that correction of merotelic attachment in anaphase is tension dependent and requires an Ase1/Prc1-dependent mechanism that prevents spindle collapse and thus asymmetric division and/or the appearance of the cut phenotype.
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Affiliation(s)
- Thibault Courtheoux
- Université de Toulouse, Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération UMR5088, F-31062 Toulouse, France
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Suarez IAR, Gay G, Ladino A, Gonzalez Mancera A, Leidy C. Dynamics of Sedimentation and Deformation of GUVs Under Different Tonicity Conditions. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2675] [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: 10/19/2022] Open
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Ramesh G, Podila GK, Gay G, Marmeisse R, Reddy MS. Different patterns of regulation for the copper and cadmium metallothioneins of the ectomycorrhizal fungus Hebeloma cylindrosporum. Appl Environ Microbiol 2009; 75:2266-74. [PMID: 19233951 PMCID: PMC2675211 DOI: 10.1128/aem.02142-08] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 02/08/2009] [Indexed: 11/20/2022] Open
Abstract
Metallothioneins (MTs) are small cysteine-rich peptides involved in metal homeostasis and detoxification. We have characterized two MT genes, HcMT1 and HcMT2, from the ectomycorrhizal fungus Hebeloma cylindrosporum in this study. Expression of HcMT1 and HcMT2 in H. cylindrosporum under metal stress conditions was studied by competitive reverse transcription-PCR analysis. The full-length cDNAs were used to perform functional complementation in mutant strains of Saccharomyces cerevisiae. As revealed by heterologous complementation assays in yeast, HcMT1 and HcMT2 each encode a functional polypeptide capable of conferring increased tolerance against Cd and Cu, respectively. The expression levels of HcMT1 were observed to be at their maximum at 24 h, and they increased as a function of Cu concentration. HcMT2 was also induced by Cu, but the expression levels were lower than those for HcMT1. The mRNA accumulation of HcMT1 was not influenced by Cd, whereas Cd induced the transcription of HcMT2. Zn, Pb, and Ni did not affect the transcription of HcMT1 or of HcMT2. Southern blot analysis revealed that both of these genes are present as a single copy in H. cylindrosporum. While the promoters of both HcMT1 and HcMT2 contained the standard stress response elements implicated in the metal response, the numbers and varieties of potential regulatory elements were different in these promoters. These results show that ectomycorrhizal fungi encode different MTs and that each of them has a particular pattern of expression, suggesting that they play critical specific roles in improving the survival and growth of ectomycorrhizal trees in ecosystems contaminated by heavy metals.
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Affiliation(s)
- G Ramesh
- Thapar University, Department of Biotechnology, Bhadson Road, Patiala 147 004, India
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Rey-Suarez IA, Gay G, Ladino A, Duran E, Avila AG, Briceño JC, Gonzalez-Mancera A, Leidy C. The Role of Sedimentation and Osmotic Stress in the Regulation of Surface Drag for GUVs Moving in an Electric Field. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2361] [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: 11/25/2022] Open
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Pohl J, Delvaux M, Ell C, Gay G, May A, Mulder CJ, Pennazio M, Perez-Cuadrado E, Vilmann P. European Society of Gastrointestinal Endoscopy (ESGE) Guidelines: flexible enteroscopy for diagnosis and treatment of small-bowel diseases. Endoscopy 2008; 40:609-18. [PMID: 18612948 DOI: 10.1055/s-2008-1077371] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- J Pohl
- Department of Internal Medicine II, Dr Horst Schmidt Kliniken, Wiesbaden, Germany.
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Pingali S, Go RS, Gundrum JD, Wright L, Gay G. Adult testicular lymphoma in the United States (1985–2004): Analysis of 3,669 cases from the National Cancer Data Base (NCDB). J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.19503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Gachet Y, Reyes C, Courthéoux T, Goldstone S, Gay G, Serrurier C, Tournier S. Sister kinetochore recapture in fission yeast occurs by two distinct mechanisms, both requiring Dam1 and Klp2. Mol Biol Cell 2008; 19:1646-62. [PMID: 18256284 PMCID: PMC2291439 DOI: 10.1091/mbc.e07-09-0910] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In eukaryotic cells, proper formation of the spindle is necessary for successful cell division. We have studied chromosome recapture in the fission yeast Schizosaccharomyces pombe. We show by live cell analysis that lost kinetochores interact laterally with intranuclear microtubules (INMs) and that both microtubule depolymerization (end-on pulling) and minus-end-directed movement (microtubule sliding) contribute to chromosome retrieval to the spindle pole body (SPB). We find that the minus-end-directed motor Klp2 colocalizes with the kinetochore during its transport to the SPB and contributes to the effectiveness of retrieval by affecting both end-on pulling and lateral sliding. Furthermore, we provide in vivo evidence that Dam1, a component of the DASH complex, also colocalizes with the kinetochore during its transport and is essential for its retrieval by either of these mechanisms. Finally, we find that the position of the unattached kinetochore correlates with the size and orientation of the INMs, suggesting that chromosome recapture may not be a random process.
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Affiliation(s)
- Yannick Gachet
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Céline Reyes
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Thibault Courthéoux
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Sherilyn Goldstone
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Guillaume Gay
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Céline Serrurier
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
| | - Sylvie Tournier
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération (LBCMCP), Centre National de la Recherche Scientifique, Université de Toulouse, 31062 Toulouse, France
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Abstract
BACKGROUND INFORMATION In eukaryotic cells, proper formation of the spindle is necessary for successful cell division. For faithful segregation of sister chromatids, each sister kinetochore must attach to microtubules that extend to opposite poles (chromosome bi-orientation). At the metaphase-anaphase transition, cohesion between sister chromatids is removed, and each sister chromatid is pulled to opposite poles of the cell by microtubule-dependent forces. RESULTS We have studied the role of the minus-end-directed motor protein dynein by analysing kinetochore dynamics in fission yeast cells deleted for the dynein heavy chain (Dhc1) or the light chain (Dlc1). In these mutants, we found an increased frequency of cells showing defects in chromosome segregation, which leads to the appearance of lagging chromosomes and an increased rate of chromosome loss. By following simultaneously kinetochore dynamics and localization of the checkpoint protein Mad2, we provide evidence that dynein function is not necessary for spindle-assembly checkpoint inactivation. Instead, we have demonstrated that loss of dynein function alters chromosome segregation and activates the Mad2-dependent spindle-assembly checkpoint. CONCLUSIONS These results show an unexpected role for dynein in the control of chromosome segregation in fission yeast, most probably operating during the process of bi-orientation during early mitosis.
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Affiliation(s)
- Thibault Courtheoux
- LBCMCP-CNRS UMR5088, Institut d'Exploration, Fonctionelle des Génomes (IFR109), Université Paul, Sabatier, 118 route de Narbonne, 31062 Toulouse, France
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Pohl J, Blancas JM, Cave D, Choi KY, Delvaux M, Ell C, Gay G, Jacobs MAJM, Marcon N, Matsui T, May A, Mulder CJ, Pennazio M, Perez-Cuadrado E, Sugano K, Vilmann P, Yamamoto H, Yano T, Zhong JJ. Consensus report of the 2nd International Conference on double balloon endoscopy. Endoscopy 2008; 40:156-60. [PMID: 18253908 DOI: 10.1055/s-2007-966994] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- J Pohl
- Department of Internal Medicine II, Dr. Horst Schmidt Kliniken, Wiesbaden, Germany.
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Affiliation(s)
- G Gay
- Department of Internal Medicine and Digestive Diseases, Hôpitaux de Brabois, CHU de Nancy, Vandoeuvre Nancy, France
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Badaeva ED, Dedkova OS, Gay G, Pukhalskyi VA, Zelenin AV, Bernard S, Bernard M. Chromosomal rearrangements in wheat: their types and distribution. Genome 2008; 50:907-26. [PMID: 18059554 DOI: 10.1139/g07-072] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four hundred and sixty polyploid wheat accessions and 39 triticale forms from 37 countries of Europe, Asia, and USA were scored by C-banding for the presence of translocations. Chromosomal rearrangements were detected in 70 of 208 accessions of tetraploid wheat, 69 of 252 accessions of hexaploid wheat, and 3 of 39 triticale forms. Altogether, 58 types of major chromosomal rearrangements were identified in the studied material; they are discussed relative to 11 additional translocation types described by other authors. Six chromosome modifications of unknown origin were also observed. Among all chromosomal aberrations identified in wheat, single translocations were the most frequent type (39), followed by multiple rearrangements (9 types), pericentric inversions (9 types), and paracentric inversions (3 types). According to C-banding analyses, the breakpoints were located at or near the centromere in 60 rearranged chromosomes, while in 52 cases they were in interstitial chromosome regions. In the latter case, translocation breakpoints were often located at the border of C-bands and the euchromatin region or between two adjacent C-bands; some of these regions seem to be translocation "hotspots". Our results and data published by other authors indicate that the B-genome chromosomes are involved in translocations most frequently, followed by the A- and D-genome chromosomes; individual chromosomes also differ in the frequencies of translocations. Most translocations were detected in 1 or 2 accessions, and only 11 variants showed relatively high frequencies or were detected in wheat varieties of different origins or from different species. High frequencies of some translocations with a very restricted distribution could be due to a "bottleneck effect". Other types seem to occur independently and their broad distribution can result from selective advantages of rearranged genotypes in diverse environmental conditions. We found significant geographic variation in the spectra and frequencies of translocation in wheat: the highest proportions of rearranged genotypes were found in Central Asia, the Middle East, Northern Africa, and France. A low proportion of aberrant genotypes was characteristic of tetraploid wheat from Transcaucasia and hexaploid wheat from Middle Asia and Eastern Europe.
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Affiliation(s)
- E D Badaeva
- N.I.Vavilov Institute of General Genetics, Russian Academy of Science, Moscow 119991, Russia.
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Delvaux M, Papanikolaou IS, Fassler I, Pohl H, Voderholzer W, Rösch T, Gay G. Esophageal capsule endoscopy in patients with suspected esophageal disease: double blinded comparison with esophagogastroduodenoscopy and assessment of interobserver variability. Endoscopy 2008; 40:16-22. [PMID: 18058656 DOI: 10.1055/s-2007-966935] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [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: 01/01/2023]
Abstract
BACKGROUND AND STUDY AIMS The study aim was to compare the diagnostic yield of capsule endoscopy and esophagogastroduodenoscopy (EGD) in patients with suspected esophageal disease. Secondary aims were to assess interobserver variability of capsule endoscopy readings and safety. PATIENTS AND METHODS In total, 98 patients (53 men, 53 +/- 13 years) with an indication for EGD were included. The patient population was artificially enriched to include two thirds of patients with abnormal esophageal findings at EGD, which was followed by capsule endoscopy. Capsule recordings were blindly read by three endoscopists, one from the center that recruited the patient and two from the other center. Study outcomes were the findings described on EGD and capsule endoscopy, agreement between EGD and capsule endoscopy for findings, quality of the capsule recording, and interobserver agreement for capsule endoscopy quality and findings. RESULTS EGD was normal in 34 patients and showed esophageal findings in 62 (esophagitis 28, hiatus hernia 21, varices 21, Barrett's esophagus 11, others 7). Average esophageal transit time of the capsule was 361 +/- 393 seconds. Capsule endoscopy was normal in 36 patients but detected esophagitis in 23, hiatus hernia in 0, varices in 23, Barrett's esophagus in 18, and others in 4. The positive predictive value of capsule endoscopy was 80.0 % and the negative predictive value was 61.1 %. Overall agreement per patient was moderate between EGD and capsule endoscopy for the per-patient (kappa = 0.42) and per-findings (kappa = 0.40) analyses. Interobserver agreement between capsule endoscopy readings was moderate for findings (kappa = 0.39) and quality assessment (kappa = 0.24). No adverse event was observed after either EGD or capsule endoscopy. CONCLUSION In this study, despite artificial prevalence enrichment, capsule endoscopy showed a moderate sensitivity and specificity in the detection of esophageal diseases.
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Affiliation(s)
- M Delvaux
- Department of Internal Medicine and Digestive Pathology, Hôpitaux de Brabois, CHU de Nancy, France.
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Barthet M, Napoléon B, Palazzo L, Chemali M, Letard JC, Laugier R, Arpurt JP, Boyer J, Boustière C, Canard JM, Cassigneul J, Dalbiès PA, Escourrou J, Gay G, Ponchon T, Richard-Molard B, Sautereau D, Tucat G, Vedrenne B. Management of cystic pancreatic lesions found incidentally. Endoscopy 2007; 39:926-8. [PMID: 17968813 DOI: 10.1055/s-2007-966786] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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Mergener K, Ponchon T, Gralnek I, Pennazio M, Gay G, Selby W, Seidman EG, Cellier C, Murray J, de Franchis R, Rösch T, Lewis BS. Literature review and recommendations for clinical application of small-bowel capsule endoscopy, based on a panel discussion by international experts. Consensus statements for small-bowel capsule endoscopy, 2006/2007. Endoscopy 2007; 39:895-909. [PMID: 17968807 DOI: 10.1055/s-2007-966930] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- K Mergener
- Digestive Health Specialists, Tacoma, Washington, USA
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Boyer J, Laugier R, Chemali M, Arpurt JP, Boustière C, Canard JM, Dalbies PA, Gay G, Escourrou J, Napoléon B, Palazzo L, Ponchon T, Richard-Mollard B, Sautereau D, Tucat G, Vedrenne B. French Society of Digestive Endoscopy SFED guideline: monitoring of patients with Barrett's esophagus. Endoscopy 2007; 39:840-2. [PMID: 17703397 DOI: 10.1055/s-2007-966653] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
BACKGROUND AND STUDY AIMS The endoscopes that were developed for double-balloon enteroscopy have been successfully used in cases of failed colonoscopy. This study was a pilot series in which a new colonoscope was tested that utilized this double-balloon principle. PATIENTS AND METHODS A total of 29 patients (5 men, 24 women; mean age 54 years) in whom conventional colonoscopy had failed were included in this study. Both the failed colonoscopy and the double-balloon colonoscopy procedures were performed under general anesthesia, the usual practice in France. A prototype instrument (working length 152 cm, diameter 9.4 mm) designed to incorporate the principles of double-balloon enteroscopy was used. The completeness of colonoscopy was assessed according to conventional criteria by the achievement of a stable position in the cecum. The indicatons for the procedure, the time to reach the cecum, the need for fluoroscopic control, and adverse events were recorded. RESULTS The previous colonoscopy failed due adhesions (n = 16), or to long or fixed loops (n = 13). Complete colonoscopy using the balloon method was achieved in 28/29 patients, taking an average time of 18 +/- 14 minutes; a long sigmoid loop limited the examination to the left flexure in one patient. Balloon colonoscopy using double-balloon methodology was used in 24 patients and the instrument was used without an overtube (i. e. using a single-balloon technique) in five patients. Fluoroscopy was used in 16 patients to monitor endoscope progression. No complications were reported. CONCLUSIONS Double-balloon colonoscopy enables full colonic examination in almost all patients with a previous incomplete colonoscopy. The overtube should be used in most cases. The use of fluoroscopic assessment of scope progression could be reduced further with increasing experience.
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Affiliation(s)
- G Gay
- Department of Internal Medicine and Digestive Diseases, Hôpitaux de Brabois, CHU de Nancy, Vandoeuvre les Nancy, France
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Gay G, Azouni A. Concentration of soluble and nonsoluble zinc-based impurities by unidirectional freezing: basis for a method of sludges treatment. Environ Sci Technol 2007; 41:5466-70. [PMID: 17822118 DOI: 10.1021/es0625374] [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] [Indexed: 05/17/2023]
Abstract
Heavy metals are known to be significant pollutants in sludges produced by wastewater treatment. A newtechnique to make the metallic contaminants migrate is to submit such sludges to a slow freezing in order to purify the frozen region and to concentrate impurities in the non-frozen zone. In this paper, we apply this method to model contaminated sludges consisting of clayey suspensions charged with a heavy metal (zinc). The effect of some physicochemical parameters (zinc and clay concentrations, pH) on the effectiveness of the method is experimentally investigated. The pH is the most relevant parameter and the highest purification rate (approximately 80%) is obtained for pH approximately 9.
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Affiliation(s)
- Guillaume Gay
- Laboratoire des Matériaux et des Structures du Génie Civil (U.M.R. 113), Cité Descartes, 2 allge Kepler, 77420 Champs-sur-Marne, France.
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Edge SB, Stewart A, Patel-Parekh L, Gay G, Palis B, Ko C. Measuring the quality of breast cancer care: National variation in the use of radiation among women under age 70. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.599] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
599 The National Quality Forum (NQF) recently adopted accountability cancer quality measures. Careful specification of target populations makes it so that omission of recommended therapy should be uncommon. One measure is use of radiation (RT) with breast conserving therapy (BCT) for women under age 70. This study examines nationwide use of RT in 2003–04 to determine the extent of variation and the need for improvement within these tight specifications. Methods: Data from 1,303 hospitals reporting to the National Cancer Data Base (NCDB) on women under age 70 treated with BCT in 2003–04 for invasive breast cancer were examined for factors associated with the use of RT in a multivariate model. The attributable provider unit was the reporting hospital. Results: Overall among 90,611 women under age 70, RT was reported with BCT in 74.5%. RT began within 6 months diagnosis in 54% and 1 yr in 74.2%. On multivariable analysis ( Table 1 ), RT was significantly less likely among African American and Hispanic vs. Caucasian women, those with less vs. more education, with no insurance or Medicaid vs. managed care, those with Charlson comorbidity > 0, women treated outside the Great Lakes/Midwest census regions, and treated at hospitals in the lower vs. higher quartiles of case volume. RT was administered to 73% of women in non-urban hospitals, and to 82% of women in urban hospitals. RT was administered to 75% and 77% of women age 50 - 59 and 60 - 69, respectively, compared to 68% and 72% of women age < 40 and 40 - 49. Conclusions: Despite limiting measurement to populations that should clearly receive RT with BCT, there are significant variations associated with patient and institutional characteristics. Reporting cancer care quality data is important, and the use of RT with BCT is a key quality measure for improvement and provider accountability. [Table: see text] No significant financial relationships to disclose.
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Affiliation(s)
- S. B. Edge
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
| | - A. Stewart
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
| | - L. Patel-Parekh
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
| | - G. Gay
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
| | - B. Palis
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
| | - C. Ko
- Roswell Park Cancer Inst, Buffalo, NY; American College of Surgeons, Chicago, IL
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Kalkum F, Gay G, Alloschery O, Weiner J, Lezec HJ, Xie Y, Mansuripur M. Surface-wave interferometry on single subwavelength slit-groove structures fabricated on gold films. Opt Express 2007; 15:2613-2621. [PMID: 19532500 DOI: 10.1364/oe.15.002613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We apply the technique of far-field interferometry to measure the properties of surface waves generated by two-dimensional (2D) single subwavelength slit-groove structures on gold films. The effective surface index of refraction n(surf) measured for the surface wave propagating over a distance of more than 12 mum is determined to be n(surf) = 1.016+/-0.004, to within experimental uncertainty close to the expected bound surface plasmon-polariton (SPP) value for a Au/Air interface of n (spp) = 1.018. We compare these measurements to finite-difference-time-domain (FDTD) numerical simulations of the optical field transmission through these devices. We find excellent agreement between the measurements and the simulations for n(surf). The measurements also show that the surface wave propagation parameter k(surf) exhibits transient behavior close to the slit, evolving smoothly from greater values asymptotically toward k (spp) over the first 2-3 mum of slit-groove distance x(sg). This behavior is confirmed by the FDTD simulations.
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Gay G, Alloschery O, Weiner J, Lezec HJ, O'Dwyer C, Sukharev M, Seideman T. Surface quality and surface waves on subwavelength-structured silver films. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 75:016612. [PMID: 17358280 DOI: 10.1103/physreve.75.016612] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Indexed: 05/14/2023]
Abstract
We analyze the physical-chemical surface properties of single-slit, single-groove subwavelength-structured silver films with high-resolution transmission electron microscopy and calculate exact solutions to Maxwell's equations corresponding to recent far-field interferometry experiments using these structures. Contrary to a recent suggestion the surface analysis shows that the silver films are free of detectable contaminants. The finite-difference time-domain calculations, in excellent agreement with experiment, show a rapid fringe amplitude decrease in the near zone (slit-groove distance out to 3-4 wavelengths). Extrapolation to slit-groove distances beyond the near zone shows that the surface wave evolves to the expected bound surface plasmon polariton (SPP). Fourier analysis of these results indicates the presence of a distribution of transient, evanescent modes around the SPP that dephase and dissipate as the surface wave evolves from the near to the far zone.
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Affiliation(s)
- G Gay
- IRSAMC/LCAR, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
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44
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Napoleon B, Ponchon T, Lefebvre RR, Heresbach D, Canard JM, Calazel Benque A, Boustiere C, Gay G, Laugier R. French Society of Digestive Endoscopy (SFED) Guidelines on performing a colonoscopy. Endoscopy 2006; 38:1152-5. [PMID: 17111341 DOI: 10.1055/s-2006-944790] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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Gay G, Alloschery O, de Lesegno BV, Weiner J, Lezec HJ. Surface wave generation and propagation on metallic subwavelength structures measured by far-field interferometry. Phys Rev Lett 2006; 96:213901. [PMID: 16803235 DOI: 10.1103/physrevlett.96.213901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Indexed: 05/10/2023]
Abstract
Transmission spectra of metallic films or membranes perforated by arrays of subwavelength slits or holes have been widely interpreted as resonance absorption by surface plasmon polaritons. Alternative interpretations involving evanescent waves diffracted on the surface have also been proposed. These two approaches lead to divergent predictions for some surface wave properties. Using far-field interferometry, we have carried out a series of measurements on elementary one-dimensional subwavelength structures with the aim of testing key properties of the surface waves and comparing them to predictions of these two points of view.
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Affiliation(s)
- G Gay
- IRSAMC/LCAR, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
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Napoléon B, Boneu B, Maillard L, Samama CM, Schved JF, Gay G, Ponchon T, Sautereau D, Canard JM. Guidelines of the French Society for Digestive Endoscopy (SFED). Endoscopy 2006; 38:632-8. [PMID: 16586249 DOI: 10.1055/s-2006-925086] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- B Napoléon
- Société Française d'Endoscopie Digestive (SFED), Lyon, France.
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47
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Affiliation(s)
- G Gay
- Dept. of Internal Medicine and Gastrointestinal Pathology, Brabois Hospital, Centre Hospitalier Universitaire de Nancy, Nancy, France.
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Abstract
BACKGROUND AND STUDY AIM Video capsule endoscopy and push-and-pull enteroscopy (PPE), both allow a complete examination of the small bowel in patients with suspected intestinal disorders. Due to the invasiveness of PPE, indications should probably be selective. The aim of the present prospective study was to evaluate the outcome of an approach whereby capsule endoscopy was used to select patients in whom PPE was indicated. PATIENTS AND METHODS 164 patients were included (90 men; age 54+/-18 years) with various indications for small-bowel investigation, such as obscure bleeding (n=88), suspected Crohn's (n=14) or celiac (n=12) disease, or known or strongly suspected localized diseases such as neoplasms (n = 18) for biopsy. Four patients with a suspected intestinal stenosis underwent PPE without prior capsule endoscopy. In the remaining 160 patients, who had a capsule endoscopy, PPE was selected if there were lesions requiring biopsy or angiodysplasias to be treated by argon plasma coagulation (APC). Regarding the insertion route, an anal PPE was indicated if the capsule transit time from ingestion to arrival at the lesion was >or= 75 % of the total time from ingestion to arrival at the cecum. After gut cleansing, PPE was performed with general anesthesia, and the small bowel was examined until the lesion was reached or the scope could not be advanced further. If the suspected lesion had not been reached, a second procedure was performed through the alternative route, under the same conditions. RESULTS The diagnostic yield of capsule endoscopy was 75 %. According to the indications, 47 PPE procedures were performed in 42 patients, including 33 through the oral route, 4 through the anal route and 5 combined ones. Indications were: suspicion of intestinal tumor (n=13), celiac disease with chronic bleeding (n=4), suspicion of Crohn's disease (n=3), treatment of significant arteriovenous malformations (AVMs) (n=10), diffuse enteropathies (n=3), nonsteroidal anti-inflammatory drug (NSAID)-related conditions (n=2), and obscure digestive bleeding (n=3). Lesions detected by capsule endoscopy were reached by PPE in all but two cases. The positive predictive value (PPV) of capsule endoscopy to make a correct indication for PPE was 94.7 % and the negative predictive value (NPV) was 98.3 %. The PPV and NPV of a time index of > 0.75 to start via the anal route were 94.7 % and 96.7 %. No complications were observed and all patients were discharged the day after the procedure. Follow-up at 9 months showed that capsule endoscopy followed by PPE had positively influenced the management of 90.5 % of the patients. CONCLUSIONS The use of capsule endoscopy as a filter for PPE results in effective management of patients with various intestinal diseases. Capsule endoscopy can also direct the choice of route of PPE; a time index of > 0.75 appears to reliably indicate an anal route so that a double procedure is required in only about 12 % of cases.
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Affiliation(s)
- G Gay
- Department of Internal Medicine and Digestive Diseases, CHU de Nancy, Nancy, France
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Reddy SM, Hitchin S, Melayah D, Pandey AK, Raffier C, Henderson J, Marmeisse R, Gay G. The auxin-inducible GH3 homologue Pp-GH3.16 is downregulated in Pinus pinaster root systems on ectomycorrhizal symbiosis establishment. New Phytol 2006; 170:391-400. [PMID: 16608463 DOI: 10.1111/j.1469-8137.2006.01677.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In an attempt to determine whether auxin-regulated plant genes play a role in ectomycorrhizal symbiosis establishment, we screened a Pinus pinaster root cDNA library for auxin-upregulated genes. This allowed the identification of a cDNA, Pp-GH3.16, which encodes a polypeptide sharing extensive homologies with GH3 proteins of different plants. Pp-GH3.16 was specifically upregulated by auxins and was not affected by cytokinin, gibberellin, abscisic acid or ethylene, or by heat shock, water stress or anoxia. Pp-GH3.16 mRNAs were quantified in pine roots inoculated with two ectomycorrhizal fungi, Hebeloma cylindrosporum and Rhizopogon roseolus. Surprisingly, Pp-GH3.16 was downregulated following inoculation with both fungal species. The downregulation was most rapid on establishment of symbiosis with an indole-3-acetic acid (IAA)-overproducing mutant of H. cylindrosporum, which overproduced mycorrhizas characterized by a hypertrophic Hartig net. This indicates that, despite being auxin-inducible, Pp-GH3.16 can be downregulated on establishment of symbiosis with a fungus that releases auxin. By contrast, Pp-GH3.16 was not downregulated in pine root systems inoculated with a nonmycorrhizal mutant of H. cylindrosporum, suggesting that the downregulation we observed in mycorrhizal root systems was a component of the molecular cross-talk between symbiotic partners at the origin of differentiation of symbiotic structures.
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Affiliation(s)
- S M Reddy
- Université Lyon 1, UMR CNRS 5557, USC INRA 1193 d'Ecologie Microbienne Bât. A. Lwoff, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex, France
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50
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Korman LY, Delvaux M, Gay G, Hagenmuller F, Keuchel M, Friedman S, Weinstein M, Shetzline M, Cave D, de Franchis R. Capsule endoscopy structured terminology (CEST): proposal of a standardized and structured terminology for reporting capsule endoscopy procedures. Endoscopy 2005; 37:951-9. [PMID: 16189767 DOI: 10.1055/s-2005-870329] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- L Y Korman
- Division of Gastroenterology, Dept. of Veterans Affairs Medical Center, Washington, DC, USA
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