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Aussenac R, Monnet JM, Klopčič M, Hawryło P, Socha J, Mahnken M, Gutsch M, Cordonnier T, Vallet P. Diameter, height and species of 42 million trees in three European landscapes generated from field data and airborne laser scanning data. Open Res Eur 2023; 3:32. [PMID: 38288290 PMCID: PMC10823913 DOI: 10.12688/openreseurope.15373.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 01/31/2024]
Abstract
Ecology and forestry sciences are using an increasing amount of data to address a wide variety of technical and research questions at the local, continental and global scales. However, one type of data remains rare: fine-grain descriptions of large landscapes. Yet, this type of data could help address the scaling issues in ecology and could prove useful for testing forest management strategies and accurately predicting the dynamics of ecosystem services. Here we present three datasets describing three large European landscapes in France, Poland and Slovenia down to the tree level. Tree diameter, height and species data were generated combining field data, vegetation maps and airborne laser scanning (ALS) data following an area-based approach. Together, these landscapes cover more than 100 000 ha and consist of more than 42 million trees of 51 different species. Alongside the data, we provide here a simple method to produce high-resolution descriptions of large landscapes using increasingly available data: inventory and ALS data. We carried out an in-depth evaluation of our workflow including, among other analyses, a leave-one-out cross validation. Overall, the landscapes we generated are in good agreement with the landscapes they aim to reproduce. In the most favourable conditions, the root mean square error (RMSE) of stand basal area (BA) and mean quadratic diameter (Dg) predictions were respectively 5.4 m 2.ha -1 and 3.9 cm, and the generated main species corresponded to the observed main species in 76.2% of cases.
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Affiliation(s)
- Raphaël Aussenac
- Université Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, F-38402 St-Martin-d'Hères, France
- Forêts et Sociétés, Université de Montpellier, CIRAD, Montpellier, France
- CIRAD, UPR Forêts et Sociétés, Yamoussoukro, Cote d'Ivoire
| | - Jean-Matthieu Monnet
- Université Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, F-38402 St-Martin-d'Hères, France
| | - Matija Klopčič
- University of Ljubljana, Biotechnical Faculty, Department of Forestry and Renewable Forest Resources, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Paweł Hawryło
- Department of Forest Resources Management, Faculty of Forestry, University of Agriculture in Krakow, Al. 29 Listopada 46, 31-425 Krakow, Poland
| | - Jarosław Socha
- Department of Forest Resources Management, Faculty of Forestry, University of Agriculture in Krakow, Al. 29 Listopada 46, 31-425 Krakow, Poland
| | - Mats Mahnken
- Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Telegrafenberg, 14473 Potsdam, Germany
| | - Martin Gutsch
- Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, Telegrafenberg, 14473 Potsdam, Germany
| | - Thomas Cordonnier
- Université Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, F-38402 St-Martin-d'Hères, France
- Office National des Forêts, Département Recherche Développement Innovation, Direction Territoriale Bourgogne-Franche-Comté, 21 rue du Muguet, 39100 Dole, France
| | - Patrick Vallet
- Université Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, F-38402 St-Martin-d'Hères, France
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Mahnken M, Cailleret M, Collalti A, Trotta C, Biondo C, D'Andrea E, Dalmonech D, Marano G, Mäkelä A, Minunno F, Peltoniemi M, Trotsiuk V, Nadal-Sala D, Sabaté S, Vallet P, Aussenac R, Cameron DR, Bohn FJ, Grote R, Augustynczik ALD, Yousefpour R, Huber N, Bugmann H, Merganičová K, Merganic J, Valent P, Lasch-Born P, Hartig F, Vega Del Valle ID, Volkholz J, Gutsch M, Matteucci G, Krejza J, Ibrom A, Meesenburg H, Rötzer T, van der Maaten-Theunissen M, van der Maaten E, Reyer CPO. Accuracy, realism and general applicability of European forest models. Glob Chang Biol 2022; 28:6921-6943. [PMID: 36117412 DOI: 10.1111/gcb.16384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/01/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
Forest models are instrumental for understanding and projecting the impact of climate change on forests. A considerable number of forest models have been developed in the last decades. However, few systematic and comprehensive model comparisons have been performed in Europe that combine an evaluation of modelled carbon and water fluxes and forest structure. We evaluate 13 widely used, state-of-the-art, stand-scale forest models against field measurements of forest structure and eddy-covariance data of carbon and water fluxes over multiple decades across an environmental gradient at nine typical European forest stands. We test the models' performance in three dimensions: accuracy of local predictions (agreement of modelled and observed annual data), realism of environmental responses (agreement of modelled and observed responses of daily gross primary productivity to temperature, radiation and vapour pressure deficit) and general applicability (proportion of European tree species covered). We find that multiple models are available that excel according to our three dimensions of model performance. For the accuracy of local predictions, variables related to forest structure have lower random and systematic errors than annual carbon and water flux variables. Moreover, the multi-model ensemble mean provided overall more realistic daily productivity responses to environmental drivers across all sites than any single individual model. The general applicability of the models is high, as almost all models are currently able to cover Europe's common tree species. We show that forest models complement each other in their response to environmental drivers and that there are several cases in which individual models outperform the model ensemble. Our framework provides a first step to capturing essential differences between forest models that go beyond the most commonly used accuracy of predictions. Overall, this study provides a point of reference for future model work aimed at predicting climate impacts and supporting climate mitigation and adaptation measures in forests.
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Affiliation(s)
- Mats Mahnken
- Potsdam Institute for Climate Impact Research (PIK), Leibniz Association, Potsdam, Germany
- Forest Growth and Woody Biomass Production, TU Dresden, Tharandt, Germany
| | - Maxime Cailleret
- UMR RECOVER, INRAE, Aix-Marseille University, Aix-en-Provence, France
- Forest Dynamics Unit, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Alessio Collalti
- Forest Modelling Lab, National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), Perugia, Italy
- Department of Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
- Division Impacts on Agriculture, Forests and Ecosystem Services (IAFES), Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici, Viterbo, Italy
| | - Carlo Trotta
- Department of Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
- Division Impacts on Agriculture, Forests and Ecosystem Services (IAFES), Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici, Viterbo, Italy
| | - Corrado Biondo
- Department of Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
- Division Impacts on Agriculture, Forests and Ecosystem Services (IAFES), Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici, Viterbo, Italy
| | - Ettore D'Andrea
- Forest Modelling Lab, National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), Perugia, Italy
| | - Daniela Dalmonech
- Forest Modelling Lab, National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), Perugia, Italy
| | - Gina Marano
- Forest Modelling Lab, National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), Perugia, Italy
- Department of Environmental Systems Science, Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
| | - Annikki Mäkelä
- Department of Forest Sciences, Institute for Atmospheric and Earth System Research (INAR) and Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Francesco Minunno
- Department of Forest Sciences, Institute for Atmospheric and Earth System Research (INAR) and Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | | | - Volodymyr Trotsiuk
- Forest Dynamics Unit, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Daniel Nadal-Sala
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
- Ecology Section, Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona (UB), Barcelona, Spain
| | - Santiago Sabaté
- Ecology Section, Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona (UB), Barcelona, Spain
- CREAF (Center for Ecological Research and Forestry Applications), Cerdanyola del Vallès, Spain
| | - Patrick Vallet
- LESSEM, INRAE, Univ. Grenoble Alpes, St-Martin-d'Hères, France
| | | | - David R Cameron
- UK Centre for Ecology and Hydrology, Penicuik, Midlothian, UK
| | - Friedrich J Bohn
- Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Rüdiger Grote
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany
| | | | - Rasoul Yousefpour
- Forestry Economics and Forest Planning, University of Freiburg, Freiburg, Germany
- Institute of Forestry and Conservation, John Daniels Faculty of Architecture, Landscape and Design, University of Toronto, Toronto, Ontario, Canada
| | - Nica Huber
- Department of Environmental Systems Science, Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
- Remote Sensing, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Harald Bugmann
- Department of Environmental Systems Science, Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
| | - Katarina Merganičová
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Praha, Czech Republic
- Department of Biodiversity of Ecosystems and Landscape, Institute of Landscape Ecology, Slovak Academy of Sciences, Nitra, Slovakia
| | - Jan Merganic
- Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic
| | - Peter Valent
- Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic
| | - Petra Lasch-Born
- Potsdam Institute for Climate Impact Research (PIK), Leibniz Association, Potsdam, Germany
| | - Florian Hartig
- Theoretical Ecology, University of Regensburg, Regensburg, Germany
| | | | - Jan Volkholz
- Potsdam Institute for Climate Impact Research (PIK), Leibniz Association, Potsdam, Germany
| | - Martin Gutsch
- Potsdam Institute for Climate Impact Research (PIK), Leibniz Association, Potsdam, Germany
| | - Giorgio Matteucci
- Forest Modelling Lab, National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), Perugia, Italy
| | - Jan Krejza
- Global Change Research Institute CAS, Brno, Czech Republic
- Department of Forest Ecology, Mendel University in Brno, Brno, Czech Republic
| | - Andreas Ibrom
- Department of Environmental Engineering, Technical University of Denmark (DTU), Lyngby, Denmark
| | | | - Thomas Rötzer
- Forest Growth and Yield Science, TU München, Freising, Germany
| | | | | | - Christopher P O Reyer
- Potsdam Institute for Climate Impact Research (PIK), Leibniz Association, Potsdam, Germany
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Thompson L, Cateau E, Debaive N, Bray F, Torre A, Vallet P, Paillet Y. How much does it take to be old? Modelling the time since the last harvesting to infer the distribution of overmature forests in France. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13436] [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: 10/19/2022] Open
Affiliation(s)
- Lucie Thompson
- Univ. Grenoble AlpesINRAELessem Saint Martin d'Hères France
| | - Eugénie Cateau
- Réserves Naturelles de FranceLa Bourdonnerie Dijon France
| | | | - Frédéric Bray
- Univ. Grenoble AlpesINRAELessem Saint Martin d'Hères France
| | - André Torre
- Univ. Grenoble AlpesINRAELessem Saint Martin d'Hères France
| | - Patrick Vallet
- Univ. Grenoble AlpesINRAELessem Saint Martin d'Hères France
| | - Yoan Paillet
- Univ. Grenoble AlpesINRAELessem Saint Martin d'Hères France
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Aussenac R, Pérot T, Fortin M, de Coligny F, Monnet JM, Vallet P. The Salem simulator version 2.0: a tool for predicting the productivity of pure and mixed forest stands and simulating management operations. Open Res Eur 2021; 1:61. [PMID: 37645093 PMCID: PMC10445841 DOI: 10.12688/openreseurope.13671.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/27/2021] [Indexed: 08/31/2023]
Abstract
A growing body of research suggests mixed-species stands are generally more productive than pure stands as well as less sensitive to disturbances. However, these effects of mixture depend on species assemblages and environmental conditions. Here, we present the Salem simulator, a tool that can help forest managers assess the potential benefit of shifting from pure to mixed stands from a productivity perspective. Salem predicts the dynamics of pure and mixed even-aged stands and makes it possible to simulate management operations. Its purpose is to be a decision support tool for forest managers and stakeholders as well as for policy makers. It is also designed to conduct virtual experiments and help answer research questions. In Salem, we parameterised the growth in pure stand of 12 common tree species of Europe and we assessed the effect of mixture on species growth for 24 species pairs (made up of the 12 species mentioned above). Thus, Salem makes it possible to compare the productivity of 36 different pure and mixed stands depending on environmental conditions and user-defined management strategies. Salem is essentially based on the analysis of National Forest Inventory data. A major outcome of this analysis is that we found species mixture most often increases species growth, in particular at the poorest sites. Independently from the simulator, foresters and researchers can also consider using the species-specific models that constitute Salem: the growth models including or excluding mixture effect, the bark models, the diameter distribution models, the circumference-height relationship models, as well as the volume equations for the 12 parameterised species. Salem runs on Windows, Linux, or Mac. Its user-friendly graphical user interface makes it easy to use for non-modellers. Finally, it is distributed under a LGPL license and is therefore free and open source.
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Affiliation(s)
- Raphaël Aussenac
- Univ. Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, St-Martin-d'Hères, F-38402, France
| | - Thomas Pérot
- INRAE, EFNO, Domaine des Barres, Nogent-sur-Vernisson, F-45290, France
| | - Mathieu Fortin
- Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 580 Booth Str., Ottawa, Ontario, Canada
| | | | - Jean-Matthieu Monnet
- Univ. Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, St-Martin-d'Hères, F-38402, France
| | - Patrick Vallet
- Univ. Grenoble Alpes, INRAE, LESSEM, 2 rue de la Papeterie-BP 76, St-Martin-d'Hères, F-38402, France
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Valade A, Luyssaert S, Vallet P, Njakou Djomo S, Jesus Van Der Kellen I, Bellassen V. Carbon costs and benefits of France's biomass energy production targets. Carbon Balance Manag 2018; 13:26. [PMID: 30547241 PMCID: PMC6292836 DOI: 10.1186/s13021-018-0113-5] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/23/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Concern about climate change has motivated France to reduce its reliance on fossil fuel by setting targets for increased biomass-based renewable energy production. This study quantifies the carbon costs and benefits for the French forestry sector in meeting these targets. A forest growth and harvest simulator was developed for French forests using recent forest inventory data, and the wood-use chain was reconstructed from national wood product statistics. We then projected wood production, bioenergy production, and carbon balance for three realistic intensification scenarios and a business-as-usual scenario. These intensification scenarios targeted either overstocked, harvest-delayed or currently actively managed stands. RESULTS All three intensification strategies produced 11.6-12.4 million tonnes of oil equivalent per year of wood-based energy by 2026, which corresponds to the target assigned to French wood-energy to meet the EU 2020 renewable energy target. Sustaining this level past 2026 will be challenging, let alone further increasing it. Although energy production targets can be reached, the management intensification required will degrade the near-term carbon balance of the forestry sector, compared to continuing present-day management. Even for the best-performing intensification strategy, i.e., reducing the harvest diameter of actively managed stands, the carbon benefits would only become apparent after 2040. The carbon balance of a strategy putting abandoned forests back into production would only break even by 2055; the carbon balance from increasing thinning in managed but untended stands would not break even within the studied time periods, i.e. 2015-2045 and 2046-2100. Owing to the temporal dynamics in the components of the carbon balance, i.e., the biomass stock in the forest, the carbon stock in wood products, and substitution benefits, the merit order of the examined strategies varies over time. CONCLUSIONS No single solution was found to improve the carbon balance of the forestry sector by 2040 in a way that also met energy targets. We therefore searched for the intensification scenario that produces energy at the lowest carbon cost. Reducing rotation time of actively managed stands is slightly more efficient than targeting harvest-delayed stands, but in both cases, each unit of energy produced has a carbon cost that only turns into a benefit between 2060 and 2080.
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Affiliation(s)
- Aude Valade
- Institut Pierre Simon Laplace, Place Jussieu 4, 75010 Paris, France
- Present Address: Global Ecology Unit CREAF-UAB, Cerdanyola del Vallès, 08193 Catalonia, Spain
| | - Sebastiaan Luyssaert
- Faculty of Science, Free University Amsterdam, VU, 1081 HV Amsterdam, The Netherlands
| | - Patrick Vallet
- Irstea, UR EFNO, Domaine des Barres, 45290 Nogent-sur-Vernisson, France
- Univ. Grenoble Alpes, Irstea, LESSEM, 38000 Grenoble, France
| | - Sylvestre Njakou Djomo
- Department of Agroecology, Aarhus University, Blichers Allé 20, P.O. Box 50, 8830 Tjele, Denmark
| | | | - Valentin Bellassen
- CESAER, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, 21000 Dijon, France
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Diot E, Brugirard S, Hascar T, Vallet P, Vallet AE, Badet F, Bouaziz A, Adelaide L, Régent A. [Movement disorders in a 32-year-old woman]. Rev Med Interne 2018; 39:597-599. [PMID: 29728281 DOI: 10.1016/j.revmed.2018.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 11/24/2022]
Affiliation(s)
- E Diot
- Service de neurologie, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - S Brugirard
- Service de neurologie, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - T Hascar
- Service de neurologie, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - P Vallet
- Service de neurologie, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - A-E Vallet
- Service de neurologie, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - F Badet
- Service de médecine interne, maladies infectieuses et tropicales, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - A Bouaziz
- Service de médecine interne, maladies infectieuses et tropicales, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France
| | - L Adelaide
- Service de médecine interne, maladies infectieuses et tropicales, hôpital Lucien-Hussel, montée du Dr-Chapuis, 38209 Vienne cedex 9, France.
| | - A Régent
- Service de médecine interne, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques 75014 Paris, France
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Guillemot J, Delpierre N, Vallet P, François C, Martin-StPaul NK, Soudani K, Nicolas M, Badeau V, Dufrêne E. Assessing the effects of management on forest growth across France: insights from a new functional-structural model. Ann Bot 2014; 114:779-93. [PMID: 24769539 PMCID: PMC4217684 DOI: 10.1093/aob/mcu059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional-structural model is presented and is used to assess the effects of management on forest functioning at a national scale. METHODS The stand process-based model (PBM) CASTANEA was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled CASTANEA-SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth. KEY RESULTS The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the CASTANEA PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale. CONCLUSIONS This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield.
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Affiliation(s)
- Joannès Guillemot
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, F-91405 Orsay, France
- For correspondence. E-mail
| | - Nicolas Delpierre
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, F-91405 Orsay, France
| | - Patrick Vallet
- Irstea, Unité de recherche ‘Ecosystèmes forestiers’, F-45290 Nogent-sur-Vernisson, France
| | - Christophe François
- CNRS, Laboratoire Ecologie, Systématique et Evolution, UMR8079, F-91405 Orsay, France
| | | | - Kamel Soudani
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, F-91405 Orsay, France
| | | | - Vincent Badeau
- INRA, Unité de recherche ‘Ecologie et Ecophysiologie forestières’, UMR1137, F-54280 Champenoux, France
| | - Eric Dufrêne
- CNRS, Laboratoire Ecologie, Systématique et Evolution, UMR8079, F-91405 Orsay, France
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Abousahl S, van Belle P, Eberle H, Ottmar H, Lynch B, Vallet P, Mayer K, Ougier M. Development of quantitative analytical methods for the control of actinides in a pyrochemical partitioning process. RADIOCHIM ACTA 2009. [DOI: 10.1524/ract.93.3.147.61614] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Summary
Advanced nuclear fuel cycles are being developed in order to reduce the long-term radiotoxicity of highly radioactive waste. Pyrochemical partitioning techniques appear particularly attractive for advanced fuel cycles in which the minor actinides are recycled. The electrochemical processes of practical importance are the electrorefining process and the liquid–liquid extraction of transuranic (TRU) elements from fission products using either non-miscible molten metal or molten salt–metal phases. Analytical methods for the accurate assay of actinide elements in these matrices needed to be developed. A quantitative assay is required in order to establish a material balance for process development and – at a later stage – for accountancy and control purposes. To this end radiometric techniques such as energy-dispersive X-ray fluorescence analysis (XRF), neutron coincidence counting (NCC) and high-resolution gamma spectrometry (HRGS) were extensively employed for the quantitative determination of actinides (U, Np, Pu, Am, Cm) in process samples. Comparative analyses were performed using inductively coupled plasma mass spectrometry (ICP-MS). The respective samples were available in small quantities (≅100 mg) either in the form of eutectic salt or in metallic form with Cd, Zr or Bi as major metallic matrix constituents.
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Vallet P, Charnay Y, Steger K, Ogier-Denis E, Kovari E, Herrmann F, Michel JP, Szanto I. Neuronal expression of the NADPH oxidase NOX4, and its regulation in mouse experimental brain ischemia. Neuroscience 2005; 132:233-8. [PMID: 15802177 DOI: 10.1016/j.neuroscience.2004.12.038] [Citation(s) in RCA: 217] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2004] [Indexed: 11/24/2022]
Abstract
Ischemia-induced neuronal damage has been linked to elevated production of reactive oxygen species (ROS) both in animal models and in humans. NADPH oxidase enzymes (NOX-es) are a major enzymatic source of ROS, but their role in brain ischemia has not yet been investigated. The present study was carried out to examine the expression of NOX4, one of the new NADPH oxidase isoforms in a mouse model of focal permanent brain ischemia. We demonstrate that NOX4 is expressed in neurons using in situ hybridization and immunohistochemistry. Ischemia, induced by middle cerebral artery occlusion resulted in a dramatic increase in cortical NOX4 expression. Elevated NOX4 mRNA levels were detectable as early as 24 h after the onset of ischemia and persisted throughout the 30 days of follow-up period, reaching a maximum between days 7 and 15. The early onset suggests neuronal reaction, while the peak period corresponds to the time of neoangiogenesis occurring mainly in the peri-infarct region. The occurrence of NOX4 in the new capillaries was confirmed by immunohistochemical staining. In summary, our paper reports the presence of the ROS producing NADPH oxidase NOX4 in neurons and demonstrates an upregulation of its expression under ischemic conditions. Moreover, a role for NOX4 in ischemia/hypoxia-induced angiogenesis is suggested by its prominent expression in newly formed capillaries.
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Affiliation(s)
- P Vallet
- Department of Psychiatry, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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Paradis E, Clavel S, Julien P, Murthy MRV, de Bilbao F, Arsenijevic D, Giannakopoulos P, Vallet P, Richard D. Lipoprotein lipase and endothelial lipase expression in mouse brain: regional distribution and selective induction following kainic acid-induced lesion and focal cerebral ischemia. Neurobiol Dis 2004; 15:312-25. [PMID: 15006701 DOI: 10.1016/j.nbd.2003.09.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [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: 03/27/2003] [Revised: 09/02/2003] [Accepted: 09/26/2003] [Indexed: 01/21/2023] Open
Abstract
Lipoprotein and endothelial lipases are members of the triglyceride lipase gene family. These genes are expressed in the brain, where the encoded proteins are fulfilling functions that have yet to be elucidated. In this study, we examined the distribution of their respective mRNAs in the C57BL/6 mouse brain by in situ hybridization. In control mice, we observed widespread expression of lipoprotein lipase (LPL) mRNA mainly in pyramidal cells of the hippocampus (CA1, CA2 and CA3 areas), in the striatum and in several cortical areas. Endothelial lipase (EL) mRNA expression was restricted to CA3 pyramidal cells of the hippocampus, to ependymal cells in the ventral part of the third ventricle and to some cortical cell layers. To gain insight into the role played by lipases in the brain, neurodegeneration was induced by intraperitoneal injection of kainic acid (KA) or by occlusion of the middle cerebral artery (MCA). Upon injection of KA, a rapid increase in EL mRNA expression was observed in the piriform cortex, hippocampus, thalamus and neocortex. However, the levels of LPL mRNA were unaffected by KA injection. Remarkably, after focal cerebral ischemia, the expression of EL was unaffected whereas a dramatic increase in LPL expression was observed in neocortical areas of the lesioned side of the brain. These results show that LPL and EL transcripts are selectively upregulated in function of the type of brain injury. LPL and EL could thus fulfill a function in the pathophysiological response of the brain to injury.
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Affiliation(s)
- E Paradis
- Department of Medical Biology, Faculty of Medicine, Laval University, Ste-Foy (PQ), Canada
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11
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Cinelli P, Madani R, Tsuzuki N, Vallet P, Arras M, Zhao CN, Osterwalder T, Rülicke T, Sonderegger P. Neuroserpin, a neuroprotective factor in focal ischemic stroke. Mol Cell Neurosci 2001; 18:443-57. [PMID: 11922137 DOI: 10.1006/mcne.2001.1028] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [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: 11/22/2022] Open
Abstract
Because recent studies have indicated that tissue plasminogen activator (tPA) aggravates neurodegenerative processes in many neural pathologies, we studied whether the endogenous tPA antagonist neuroserpin has a neuroprotective effect in an animal model of focal ischemic stroke. After induction of a focal ischemic stroke in the mouse by occlusion of the middle cerebral artery, we found that microglial cells accumulated in the marginal zone of the infarct are the most important source for both plasminogen activators, tPA and uPA. To investigate the effect of neuroserpin on the size and the histology of the infarct we produced transgenic mice overexpressing neuroserpin approximately sixfold in the nervous system. In the brain of these mice the total tPA activity in the uninjured tissue was strongly reduced. After induction of a focal ischemic stroke in the transgenic mice by a permanent occlusion of the middle cerebral artery (MCA), the infarcts were 30% smaller than in the wild-type mice. Immunohistochemical analyses and in situ hybridization revealed an attenuation of the microglial activation in the reactive zone. Concomitantly, the microglial production of tPA and uPA, as well as the PA-activity in the infarct region was markedly reduced. Thus, our results indicate that neuroserpin reduces microglial activation and, therefore, the PA activity and has a neuroprotective role after focal ischemic stroke.
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Affiliation(s)
- P Cinelli
- Institute of Biochemistry, University of Zurich, Switzerland
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12
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Wehrli P, Charnay Y, Vallet P, Zhu G, Harmony J, Aronow B, Tschopp J, Bouras C, Viard-Leveugle I, French LE, Giannakopoulos P. Inhibition of post-ischemic brain injury by clusterin overexpression. Nat Med 2001; 7:977-9. [PMID: 11533682 DOI: 10.1038/nm0901-977] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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De Bilbao F, Guarin E, Nef P, Vallet P, Giannakopoulos P, Dubois-Dauphin M. Cell death is prevented in thalamic fields but not in injured neocortical areas after permanent focal ischaemia in mice overexpressing the anti-apoptotic protein Bcl-2. Eur J Neurosci 2000; 12:921-34. [PMID: 10762322 DOI: 10.1046/j.1460-9568.2000.00984.x] [Citation(s) in RCA: 44] [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] [Indexed: 11/20/2022]
Abstract
Previous studies have suggested that various apoptotic-related proteins could be involved in the death process induced by cerebral ischaemia. In order to further clarify their role and examine how the anti-apoptotic protein Bcl-2 could influence this process, the time-course of mRNA expression of various cell death genes was studied from 1 to 14 days following permanent occlusion of the middle cerebral artery in wild-type (WT) and Bcl-2 transgenic mice, within and outside the area of infarction. No differences of the infarct sizes were observed between the two groups of mice, showing that the extent of neuronal injury could not have been lowered by the Bcl-2 transgene. Seven days after the ischaemic insult, the mRNA expression of the cell death gene effector cpp32 was dramatically upregulated in the penumbra of WT and Bcl-2 transgenic mice. Interestingly, the cpp32 transcript was markedly induced from 3 days in the ipsilateral thalamus of the two groups of mice. However, apoptotic bodies were observed in the thalamic field of WT but not transgenic mice. This suggests that cpp32 mRNA may be induced in an attempt to kill the injured cells and, in contrast to the penumbra, cell death in the thalamus may be prevented in Bcl-2 transgenic mice. Based on these results, the pathophysiological mechanisms that underly neuronal damage following ischaemia need consideration in order to evaluate the extent of neuroprotection that may be afforded by the Bcl-2 anti-apoptotic protein. Although the present study does not confirm previous data showing a protective role of Bcl-2 in neocortical infarcted areas, it suggests that anti-apoptotic therapies may constitute a possible treatment for areas of the brain remote from those directly affected by ischaemia.
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Affiliation(s)
- F De Bilbao
- University Hospital Geneva, Department of Psychiatry, 2, Chemin du Petit Bel-Air, 1225 Geneva, Switzerland.
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14
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de Bilbao F, Guarin E, Nef P, Vallet P, Giannakopoulos P, Dubois-Dauphin M. Postnatal distribution of cpp32/caspase 3 mRNA in the mouse central nervous system: an in situ hybridization study. J Comp Neurol 1999; 409:339-57. [PMID: 10379822 DOI: 10.1002/(sici)1096-9861(19990705)409:3<339::aid-cne1>3.0.co;2-q] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Apoptotic cell death is a major feature of the developing nervous system and of certain neurodegenerative diseases. Various gene effectors and repressors of this type of cell death have been identified. Among them, bcl-xl and bax, which encode for antiapoptotic and proapoptotic proteins, respectively, play major roles during development. The gene cpp32 encodes for the caspase 3 cysteine protease and is a critical mediator of cell death during embryonic development in the mammalian brain. To gain insight into the possible implications of these cell death genes during the postnatal development, we investigated the expression of bax, bcl-xl, and cpp32 mRNAs by in situ hybridization in the mouse brain from birth to adulthood. Whereas bax and bcl-xl mRNAs were expressed widely in neonates and adult mice, our results showed that cpp32 mRNA levels were decreased strongly from 12 postnatal days. From 1 postnatal day to 12 postnatal days, cpp32 mRNA was expressed ubiquitously in all brain nuclei, including areas where neurogenesis occurred. A positive correlation between areas displaying high levels of mRNA and apoptotic nuclei also was shown. In the adult, cpp32 mRNA was restricted to the piriform and entorhinal cortices, the neocortex, and to areas where neurogenesis is observed (e.g., olfactory bulb and dentate gyrus). The same pattern of expression was observed in adult mice over-expressing the antiapoptotic protein Bcl-2. These results demonstrate that the expression of cpp32 mRNA is highly regulated during the mouse postnatal period, leading to a specific distribution in the adult central nervous system. Moreover, the prevention of cell death by Bcl-2 likely is not linked to the regulation of caspase mRNA levels.
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Affiliation(s)
- F de Bilbao
- Department of Psychiatry, University Hospital of Geneva, Switzerland.
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15
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Agulhon C, Charnay Y, Vallet P, Abitbol M, Kobetz A, Bertrand D, Malafosse A. Corrigendum to: distribution of mRNA for the alpha-subunit of the nicotinic acetylcholine receptor in the human fetal brain. Brain Res Mol Brain Res 1999; 63:384. [PMID: 9878844 DOI: 10.1016/s0169-328x(98)00319-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C Agulhon
- Division de Neuropsychiatrie, Hopitaux Universitaires de Geneve, Geneva, 1225 Chene-Bourg, Switzerland
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16
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Martin R, Martin G, Martin D, Vallet P, Jean M, Tétrault JP. [Effects of CO2 and adrenaline on 1% lidocaine in axillary block]. Ann Fr Anesth Reanim 1998; 16:479-82. [PMID: 9750601 DOI: 10.1016/s0750-7658(97)83340-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To compare lidocaine hydrocarbonate and lidocaine hydrochloride, with and without adrenaline, in the axillary block obtained with a neurostimulator. STUDY DESIGN Prospective, randomized, double blind study. PATIENTS Sixty-six patients undergoing surgery of the upper limb under axillary block, allocated into four groups. METHODS The criteria for evaluation were: onset time, duration and quality of sensory and motor blockades, and blood concentrations of lidocaine in 39 patients. In all patients musculocutaneous, radial, median and ulnar nerves were stimulated and the volume of local anaesthetic administered was 25 mL per square meter of body surface. Group 1 received lidocaine hydrocarbonate 1% (n = 17), group 2, lidocaine hydrocarbonate 1% with adrenaline 1/200,000 (n = 17), group 3, lidocaine hydrochloride 1% (n = 16) and group 4, lidocaine hydrochloride 1% with adrenaline 1/200,000 (n = 16). RESULTS No significant inter-group differences were found concerning sensory and motor blockades and onset time. The duration of analgesia was longer in groups CO2 + A and HCL + A. The lidocaine blood concentrations were globally lower in group HCL + A. CONCLUSIONS Considering the cost/benefit ratio and the absence of clinical benefits of lidocaine hydrocarbonate, lidocaine hydrochloride should be preferred.
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Affiliation(s)
- R Martin
- Département d'anesthésie-réanimation, Université de Sherbrooke, Province de Québec, Canada
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17
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Agulhon C, Charnay Y, Vallet P, Abitbol M, Kobetz A, Bertrand D, Malafosse A. Distribution of mRNA for the alpha4 subunit of the nicotinic acetylcholine receptor in the human fetal brain. Brain Res Mol Brain Res 1998; 58:123-31. [PMID: 9685607 DOI: 10.1016/s0169-328x(98)00113-2] [Citation(s) in RCA: 38] [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] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) present in the central nervous system (CNS), are multimeric proteins constituted of two different subunits, alpha and beta, with different subtype arrangements and different pharmacological and functional properties. By in situ hybridization, we studied the distribution of the mRNA for the alpha4 subunit of nAChRs in brains of human 25-week old normal and fragile X fetuses. A strong hybridization signal was detected throughout the thalamus, cortex, pyramidal layer of the Ammon's horn, and the granular layer of the dentate gyrus. Several other areas including the claustrum, caudate nucleus, putamen, globus pallidus, subthalamic nucleus, subiculum, entorhinal cortex, and Purkinje cell layer displayed a low to moderate radiosignal. With few exceptions, our data in the human brain agree those previously reported in the rat. Also, our data indicate that the alpha4 subunit mRNA is produced early in the development, in the more differentiated cells, and in a site-specific manner. Additionally, the alpha4 mRNA is produced in the brain of fragile X fetuses with the same pattern and same intensity than in the normal fetal brain suggesting that alpha4 subunit mRNA production is not altered in the fragile X syndrome. High levels of alpha4 subunit mRNA in human fetal brain support the hypothesis of a morphogenic role of nAChRs during the early CNS development.
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Affiliation(s)
- C Agulhon
- Division de Neuropsychiatrie, Belle-Idée, Département de Psychiatrie, Hôpitaux Universitaires de Genève (HUG), Ch. du Petit-Bel-Air 2, CH-1225 Chêne-Bourg, Geneva, Switzerland
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18
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Vallet P, Bouras C, Barberis C, Dreifuss JJ, Dubois-Dauphin M. Vasopressin binding in the cerebral cortex of the Mongolian gerbil is reduced by transient cerebral ischemia. J Comp Neurol 1995; 362:223-32. [PMID: 8576435 DOI: 10.1002/cne.903620206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 01/31/2023]
Abstract
In Mongolian gerbils, the content of vasopressin in the cerebral cortex, the striatum, and the hypothalamus is increased after induction of acute cerebral ischemia. We used an iodinated vasopressin analogue and light microscopic autoradiography to study the distribution of vasopressin V1 receptors in the brain of adult male gerbils and to evaluate the effects of a transient bilateral cerebral ischemia (6 minutes) on the density of this receptor population. The animals were killed immediately or 10, 30, or 100 hours after transient bilateral occlusion of the common carotid arteries. In control animals, specific [125I]-VPA binding sites were present in various structures of the brain (olfactory bulb, anterior olfactory nucleus, lateral septum, bed nucleus of the stria terminalis, median preoptic area, ventral pallidum, substantia innominata, amygdala, thalamus, hypothalamic mammillary nuclei, superior colliculus, subiculum, central gray, nucleus of the solitary tract, hypoglossal nucleus). The strongest labeling was detected in the cerebral cortex, layers 5-6. After 30-100 hours of survival time following ischemia there was a marked decrease in [125I]-VPA binding site density in these cerebral cortex layers. To a lesser degree, a decrease was also detected in the lateral septal nucleus. In contrast, labeling in other noncortical structures remained unchanged. All animals with 100 hours recovery showed a loss of cells in hippocampus (CA1 layer) and striatum. In addition, ischemia induced concomitant and proliferative changes in cortical and hippocampal astrocytes assessed by glial fibrillary acid protein immunoreactivity. These observations indicate a role for vasopressin in the cerebral cortex either on neurons or on glial cells and the modulation of vasopressin receptor expression by transient cerebral ischemia.
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Affiliation(s)
- P Vallet
- Department of Psychiatry, University Medical Center, Geneva, Switzerland
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19
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Abstract
Central oxytocin (OT) receptors were labelled in 3-month-old and 20-month-old rats with an iodinated OT antagonist. Comparison of the autoradiograms by quantitative image analysis revealed in the old animals a significant reduction of binding in three regions; the number of labelled OT receptors was decreased by 90% in the head of the caudate putamen, by 68% in the olfactory tubercle, and by 41% in the ventromedial hypothalamic nucleus. Previous studies had shown that the expression of OT receptors in the olfactory tubercle and in the ventromedial hypothalamic nucleus was dependent upon gonadal steroids. Therefore we hypothesize that the reduced number of OT receptors in the latter two structures of aged rats was the consequence of the 4-fold decrease of plasma testosterone that we found in this age. Another mechanism may be responsible for the marked reduction of OT receptors in the caudate putamen.
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Affiliation(s)
- Y Arsenijevic
- Department of Physiology, University Medical Center, Geneva 4, Switzerland
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20
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Geraldes CF, Sherry AD, Vallet P, Maton F, Muller RN, Mody TD, Hemmi G, Sessler JL. Nuclear magnetic relaxation dispersion studies of water-soluble gadolinium(III)-texaphyrin complexes. J Magn Reson Imaging 1995; 5:725-9. [PMID: 8748493 DOI: 10.1002/jmri.1880050618] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Water proton 1/T1 nuclear magnetic relaxation dispersion (NMRD) profiles were measured for a water-soluble gadolinium(III) texaphyrin (Gd-tex) complex as a function of temperature and in the presence and absence of 5% human serum albumin (HSA). Upon dissolving the complex in water (0.259 mM), the water relaxivity values decreased with time but remained higher than those of free GD3+(aq) at all fields. Concurrent measurements of free Gd3+ using metallochromic dyes indicated that demetallation of the texaphyrin did not occur over a period of several days at 37 degrees C. The high relaxivity values and shape of the NMRD profile of this complex may be ascribed to a combination of large water coordination number (q estimated at 3.5) and long tau R. Upon mixing an aqueous solution of the complex with 5% HSA, the low-field water relaxivity slightly decreased whereas the high-field relaxivity increased relative to the free complex in water, and the relaxivities became nearly independent of temperature. These observations indicate that water exchange between the inner coordination sphere of Gd-tex and bulk water becomes limiting in the presence of HSA.
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Affiliation(s)
- C F Geraldes
- Department of Biochemistry, University of Coimbra, Portugal
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21
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Vallet P, Van Haverbeke Y, Bonnet PA, Subra G, Chapat JP, Muller RN. Relaxivity enhancement of low molecular weight nitroxide stable free radicals: importance of structure and medium. Magn Reson Med 1994; 32:11-5. [PMID: 8084224 DOI: 10.1002/mrm.1910320103] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The longitudinal relaxivities of seven water-soluble nitroxide derivatives of low-molecular weight have been measured at 5 degrees C and 37 degrees C in water and in serum between 0.01 and 200 MHz. The nuclear magnetic relaxation dispersion (NMRD) profiles show a clear relationship between the relaxivity observed in serum and the relative balance of the hydrophobic/hydrophilic character of the paramagnetic molecules. From the data analysis, contributions arising from a population of nitroxides characterized by reduced mobility can be extracted. The values of the correlation times are consistent with a system involving nitroxides adsorbed at the surface of albumin and magnetically interacting with the protons of hydrogen bonded water molecules.
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Affiliation(s)
- P Vallet
- Department of Organic Chemistry, University of Mons-Hainaut, Belgium
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22
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Chaouni-Benabdallah A, Subra G, Bonnet PA, Fernandez JP, Chapat JP, Vallet P, Muller RN. Nitroxides: Synthesis and paramagnetic properties of an α-hydroxymethyl derivative of DOXYL. Tetrahedron 1994. [DOI: 10.1016/s0040-4020(01)81211-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Zaphiropoulos A, Charnay Y, Vallet P, Constantinidis J, Bouras C. Immunohistochemical distribution of corticotropin-like intermediate lobe peptide (CLIP) immunoreactivity in the human brain. Brain Res Bull 1991; 26:99-111. [PMID: 1849784 DOI: 10.1016/0361-9230(91)90194-o] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The immunocytochemical distribution of CLIP (corticotropin-like intermediate lobe peptide) or ACTH(18-39), a small biologically active peptide, was examined in the human brain, using a monoclonal antibody against this peptide. Groups of CLIP-immunoreactive cell bodies, small to medium size and bipolar or triangular in shape, were found in the basal hypothalamus extending from the retrochiasmatic region to the premammillary nuclei area. Immunoreactive fibers with varicosities, terminals and "pipe shape" structures, were distributed within the hypothalamus, limbic structures, the brainstem and spinal cord nuclei, forming a particularly rich network in the hypothalamus, the preoptic area, the septal region, the amygdala and the upper brainstem periaqueductal gray matter. The above neuroanatomical observations confirm and extend previous findings in animals, strengthening even more the possibility that this peptide may be involved in numerous behavioral, autonomic and physiological functions such as regulation of sleep-waking cycle, pain control and respiratory and cardiovascular regulation.
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24
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Martin R, Vallet P. Brachial plexus block: is a half-ring injection necessary? Reg Anesth 1991; 16:63. [PMID: 2007111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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25
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Golaz J, Charnay Y, Vallet P, Bouras C. [Alzheimer's disease and Down's syndrome. Some recent etiopathogenic data]. Encephale 1991; 17:29-31. [PMID: 1669030] [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: 12/28/2022]
Abstract
The present status of research clearly demonstrates the occurrence of lesions characteristic of Alzheimer's disease in patients suffering from a Down's syndrome or trisomy 21. The senile plaques appear very early in trisomy 21 (from the age of 20) and are constant after 40 or 45 years. In these two illnesses, the beta-amyloid protein or A4 protein (4.2 kD) leads to deposits in preferential regions of the central nervous system within two compartments: 1) intracellular, contributing to the formation of neurofibrillary tangles and 2) extracellular, making up the amyloid center of senile plaques as well as around the wall of some blood vessels, then corresponding to the amyloid congophilic angiopathies. Unexpectedly, larger proteins including the A4 sequence have been shown to be normally present in several tissues of normal as well as sick individuals and represent possible precursors of the A4 protein. Alzheimer's disease may happen either sporadically or following a familial incidence associated with an autosomic dominant mode of transmission. Moreover, the risk of incidence of trisomy 21 seems to be enhanced for collaterals of Alzheimer's disease patients. Since 1987, the use of molecular biology tools has revealed particularly fruitful. A linkage analysis has been undertaken that showed an association of the putative gene for the familial form of Alzheimer's disease (FAD) with the gene coding for amyloid precursor proteins (APP).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Golaz
- Institutions Universitaires Psychiatriques de Genève, Division de Psychopathologie Morphologique, Chêne-Bourg, Suisse
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26
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Muller RN, Vallet P, Maton F, Roch A, Goudemant JF, Vander Elst L, Gillis P, Peto S, Moiny F, Van Haverbeke Y. Recent developments in design, characterization, and understanding of MRI and MRS contrast media. Invest Radiol 1990; 25 Suppl 1:S34-6. [PMID: 2283249 DOI: 10.1097/00004424-199009001-00016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- R N Muller
- Department of Organic Chemistry, University of Mons, Belgium
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27
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Muller RN, Vander Elst L, Rinck PA, Vallet P, Maton F, Fischer H, Roch A, Van Haverbeke Y. The importance of nuclear magnetic relaxation dispersion (NMRD) profiles in MRI contrast media development. Invest Radiol 1988; 23 Suppl 1:S229-31. [PMID: 3198350 DOI: 10.1097/00004424-198809001-00047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [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: 01/04/2023]
Abstract
Observation of the relaxivity of MRI contrast media over a wide range of magnetic fields is not only necessary for predicting their efficiency at any field but also compulsory for understanding and improving their mechanisms of action. The best experimental approach to this problem is the field cycling method, which allows the exploration of nuclear relaxation over a broad interval of magnetic field intensity but requires a specially dedicated instrument called a relaxometer. Particularly relevant are the relaxivity profiles of the two chelates Gd-DOTA and Gd-DTPA. Both show an important decrease from low to high fields within the current imaging range (0.02 T to 1.5 T). Although high field relaxivities of these chelates are similar, Gd-DTPA becomes less efficient in facilitating water protons relaxation at fields lower than 0.15 T. This behavior has to be related to different electronic relaxation times due to a different chelate symmetry.
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Affiliation(s)
- R N Muller
- Department of Organic Chemistry, University of Mons, Faculty of Medicine, Belgium
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28
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Maquestiau A, Flammang R, Pauwels P, Vallet P, Meyrant P, Appling JR, Abbey LE, Moran TF, Andrews RS, Johnston D. Letters to the editor. ACTA ACUST UNITED AC 1982. [DOI: 10.1002/oms.1210171211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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30
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Abstract
The superfusion of the hepatic portal vein of anaesthetized rats with hypertonic solutions of NaCl elicits a significant increase of neural activity measured in the hypothalamo-neurohypophysial tract. Superfusions of the liver or hepatic veins with hypertonic saline solutions had no effect, whereas superfusions of the portal vein also increased the firing rates of supraoptic endocrine neurones and the intramammary pressure. Results suggest that sodium chloride sensitive receptors (perhaps osmoreceptors) are located within the wall of the hepatic portal vein and mediate neurophypophysial hormone release.
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31
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Abstract
The hypothesis was tested that the neural lobe of the pituitary may modulate the release of anterior pituitary hormones. The neural lobe of anesthetized lactating rats was electrically stimulated at 30 Hz (5 sec on and 5 sec off) for 3 min while taking blood samples for RIA of ACTH. Plasma ACTH increased within 3 min by 22 +/- 9% (average +/- SEM; P less than 0.025) in intact rats and by 38 +/- 17% (P less than 0.025) in rats where the nerve supply to the median eminence and neural lobe was interrupted. Electrical stimulation of the anterior pituitary was ineffective. No significant changes in plasma ACTH were observed in rats with coagulated hypophysial portal vessels or in Brattleboro rats with congenital diabetes insipidus. Apparently, neither peripheral plasma vasopressin (estimated at 150 microU/ml maximum) nor intermediate lobe ACTH could account for the observed rise in ACTH. Results suggest a vasopressin dependent modulation of ACTH release by the neural lobe, mediated either by axon collaterals to the median eminence or by a vascular interconnection between posterior and anterior pituitaries.
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Vallet P. [On the study of the biologic phenomena in regularly variable temperature]. C R Acad Hebd Seances Acad Sci D 1967; 264:3049-52. [PMID: 4965085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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