Search

Your search keyword '"Usson, Y."' showing total 225 results
Start Over Author "Usson, Y."
225 results on '"Usson, Y."'

1. Very High-Resolution Imaging of Post-Mortem Human Cardiac Tissue Using X-Ray Phase Contrast Tomography

Author

Mirea, I., Varray, F., Zhu, Y. M., Fanton, L., Langer, M., Jouk, P. S., Michalowicz, G., Usson, Y., Magnin, I. E., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, van Assen, Hans, editor, Bovendeerd, Peter, editor, and Delhaas, Tammo, editor

Published
2015
Full Text
View/download PDF

2. Migration of cancer cells in 3D collagen medium

Author

Laforgue, L, Fertin, A, Usson, Y, Verdier, Claude, Laurent, V, LIPHY-MC2, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Biologie Computationnelle et Modélisation (TIMC-BCM ), Translational Innovation in Medicine and Complexity / Recherche Translationnelle et Innovation en Médecine et Complexité - UMR 5525 (TIMC ), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Verdier, Claude

Subjects
3D fibrous medium, Correlation method, [SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], Cancer cell migration, [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], ComputingMilieux_MISCELLANEOUS, Spatio-temporal displacement of collagen fibers
Abstract

International audience

Published
2021

10. Investigation of Myocardial Fiber Crossings in the Human Heart Using Realistic HARDI Simulation Based on PLI

Author

Wang, L., Yang, F., Michalowicz, G., Usson, Y., Jouk, P., Wang, R., Yuemin Zhu, Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales (MOTIVATE), Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

12. Imaging of dense cell cultures by multiwavelength lens-free video microscopy

Author

Allier, C., Morel, S., Vincent, R., Ghenim, L., Navarro, F., Menneteau, M., Bordy, T., HervÉ, L., Cioni, O., Gidrol, X., Usson, Y., Dinten, M., Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Mécanique et d'Ingénierie de Bordeaux (I2M), Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB)-École Nationale Supérieure d'Arts et Métiers (ENSAM), Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie à Grande Échelle (BGE - UMR S1038), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Dynamique Cellulaire et Tissulaire- Interdisciplinarité, Modèles & Microscopies (TIMC-IMAG-DyCTiM), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), École Nationale Supérieure d'Arts et Métiers (ENSAM), HESAM Université (HESAM)-HESAM Université (HESAM)-Institut Polytechnique de Bordeaux-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Dynamiques Cellulaire et Tissulaire - Interdisciplinarité, Modélisation & Microscopie (TIMC-IMAG-DyCTiM2)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

13. Validation of dMRI-Derived Fiber Orientations Using PLI in Human Fetal Hearts

Author

Yang, F., Zhu, Yue-Min, Michalowicz, G., Usson, Y., Fanton, L., Viallon, M., Clarysse, P., Jouk, P.S., Croisille, P., Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales (MOTIVATE), Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
[INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

14. Wavelet transform analysis of chromatin texture changes during heat shock

Author

Herbomel, A., Grichine, A., Arnold Fertin, Delon, A., C. Vourc'H, Souchier, C., Usson, Y., INSERM U823, équipe 8 (Immunologie Analytique des Pathologies Chroniques), Institut d'oncologie/développement Albert Bonniot de Grenoble (INSERM U823), Institut National de la Santé et de la Recherche Médicale (INSERM)-EFS-CHU Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Santé et de la Recherche Médicale (INSERM)-EFS-CHU Grenoble-Université Joseph Fourier - Grenoble 1 (UJF), LIPHY-DYFCOM, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Dynamique Cellulaire et Tissulaire- Interdisciplinarité, Modèles & Microscopies (TIMC-IMAG-DyCTiM), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Institut National de la Santé et de la Recherche Médicale (INSERM)-EFS-CHU Grenoble-Université Joseph Fourier - Grenoble 1 (UJF), ANR-08-PCVI-0004,Dynastress,Etude, par microscopie à corrélation de fluorescence, de la réponse nucléaire au stress thermique, and aspects dynamiques.(2008)

Subjects
Microscopy, Confocal, Heat Shock Transcription Factors, Cell Survival, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Image Processing, Computer-Assisted, Wavelet Analysis, Humans, Algorithms, Chromatin, Heat-Shock Response, ComputingMilieux_MISCELLANEOUS, HeLa Cells
Abstract

Texture analysis can be a useful tool to investigate the organization of chromatin. Approaches based on multiscale analysis and in particular the 'à trou' wavelet analysis has already been used for microscopy (Olivo Marin). In order to analyse texture changes, the statistical properties of the wavelet coefficient images were summarized by the first four statistical orders: mean, standard deviation, skewness and kurtosis of the coefficient image histogram. The 'à trou' transform provided a representation of the wavelet coefficients and texture parameters with the same statistical robustness throughout the scale spaces. It was applied for quantifying chromatin texture and heat-induced chromatin changes in living cells. We investigated the changes by both laser scanning and spinning disk confocal microscopies and compared the texture parameters before and after increasing duration of heat shock exposure (15 min, 30 min and 1 h). Furthermore, as activation of the heat shock response also correlates with a rapid localization of HSF1 within a few nuclear structures termed nuclear stress bodies (nSBs), we compared the dynamics of nSBs formation with that of textural changes during 1 h of continuous heat shock. Next, we studied the recovery phase following a 1-h heat shock. Significant differences were observed, particularly affecting the perinucleolar region, even for the shortest heat shock time affecting mostly the skewness and standard deviation. Furthermore, progressive changes could be observed according to the duration of heat shock, mostly affecting fine details (pixel-wise changes) as revealed by the parameters, obtained from the first- and second-order wavelet coefficients. 'A trou' wavelet texture analysis provided a sensitive and efficient tool to investigate minute changes of chromatin.

Published
2015

16. Simulación por elementos finitos de la biomecánica del corazón fetal

Author

Peña, E., Ohayon, J., Usson, Y., Azancot, A., and Doblaré, M.

Subjects
Infografia tridimensional, Finite element method, Fetus -- Malalties, Elements finits, Mètode dels, Biomecànica, Biomechanics, Fetus -- Diseases, Cor -- Propietats mecàniques, Three-dimensional modeling, Matemàtiques i estadística::Anàlisi numèrica::Mètodes en elements finits [Àrees temàtiques de la UPC], Heart -- Mechanical properties
Abstract

El objetivo de este trabajo es modelar y simular la contracción del corazón fetal a lo largo del ciclo cardí­aco con el objetivo de entender la biomecánica del mismo, con ello se pretende ayudar a comprender los factores mecánicos que pueden contribuir a la aparición de malformaciones congénitas durante la gestación. Para ello se ha desarrollado un modelo 3D de elementos finitos de un corazón fetal de 23 semanas a partir de imágenes tomadas de fotografías y datos experimentales de orientación de fibras de medidas post-mortem de un corazón fetal humano. Para el modelado de las propiedades mecánicas es necesario utilizar un modelo hiperelástico fibrado que incorpora la activación muscular como un término añadido a la función densidad de energía de deformación. A partir de la simulación numérica se obtiene la distribución de deformaciones y tensiones a lo largo de la pared del miocardio y se compara la cinemática y el volumen eyectado con resultados experimentales. Para muchos autores estas variables son algunos de las factores de los que depende el crecimiento de la pared durante la gestación y, por tanto, estos resultados pueden ayudar a una mejor compresión del crecimiento y evolución del corazón fetal. Summary: The purpose of this research is to study the fetal heart biomechanics during cardiac cycle. A 3D FEM of the human fetal heart (FH) is built by using the geometry and the fiber orientation measurements of a post-mortem FH. An anisotropic hyperelastic constitutive law describing the mechanical properties of the active myocardium is used. Kinematics of the heart and ejection fraction predicted by the model are compared with experimental observations. Our model can quantify the transmural distribution of strains and stresses during the cardiac cycle. Several authors supported the idea that fetal growth depends on the mean wall stress averaged through the space and during the cardiac cycle. For this reason, the results obtained in this work can be relevant in order to better understand the human FH growth process.

Published
2010

17. Spatial control of organic nanocyrstal nucleation in sol-gel thin films for 3D optical data storage devices or chemical multi-sensors

Author

Ibanez, A., Botzung-Appert, E., Zaccaro, Julien, Gourgon, C., Usson, Y., Baldeck, Patrice, Laboratoire des technologies de la microélectronique (LTM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Clot, Marielle

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2005

18. Modular organization of cardiac energy metabolism: energy conversion, transfer and feedback regulation

Author

Guzun, R., primary, Kaambre, T., additional, Bagur, R., additional, Grichine, A., additional, Usson, Y., additional, Varikmaa, M., additional, Anmann, T., additional, Tepp, K., additional, Timohhina, N., additional, Shevchuk, I., additional, Chekulayev, V., additional, Boucher, F., additional, Dos Santos, P., additional, Schlattner, U., additional, Wallimann, T., additional, Kuznetsov, A. V., additional, Dzeja, P., additional, Aliev, M., additional, and Saks, V., additional

Published
2014
Full Text
View/download PDF

20. Simulación por elementos finitos de la biomecánica del corazón fetal

Author

Peña Baquedano, Estefanía, Ohayon, J., Usson, Y., Azancot, A., Doblaré Castellano, Manuel, Peña Baquedano, Estefanía, Ohayon, J., Usson, Y., Azancot, A., and Doblaré Castellano, Manuel

Abstract

El objetivo de este trabajo es modelar y simular la contracción del corazón fetal a lo largo del ciclo cardí­aco con el objetivo de entender la biomecánica del mismo, con ello se pretende ayudar a comprender los factores mecánicos que pueden contribuir a la aparición de malformaciones congénitas durante la gestación. Para ello se ha desarrollado un modelo 3D de elementos finitos de un corazón fetal de 23 semanas a partir de imágenes tomadas de fotografías y datos experimentales de orientación de fibras de medidas post-mortem de un corazón fetal humano. Para el modelado de las propiedades mecánicas es necesario utilizar un modelo hiperelástico fibrado que incorpora la activación muscular como un término añadido a la función densidad de energía de deformación. A partir de la simulación numérica se obtiene la distribución de deformaciones y tensiones a lo largo de la pared del miocardio y se compara la cinemática y el volumen eyectado con resultados experimentales. Para muchos autores estas variables son algunos de las factores de los que depende el crecimiento de la pared durante la gestación y, por tanto, estos resultados pueden ayudar a una mejor compresión del crecimiento y evolución del corazón fetal., Summary: The purpose of this research is to study the fetal heart biomechanics during cardiac cycle. A 3D FEM of the human fetal heart (FH) is built by using the geometry and the fiber orientation measurements of a post-mortem FH. An anisotropic hyperelastic constitutive law describing the mechanical properties of the active myocardium is used. Kinematics of the heart and ejection fraction predicted by the model are compared with experimental observations. Our model can quantify the transmural distribution of strains and stresses during the cardiac cycle. Several authors supported the idea that fetal growth depends on the mean wall stress averaged through the space and during the cardiac cycle. For this reason, the results obtained in this work can be relevant in order to better understand the human FH growth process., Peer Reviewed

Published
2010

24. PML nuclear bodies are highly organised DNA-protein structures with a function in heterochromatin remodelling at the G2 phase

Author

Luciani, J. J., primary, Depetris, D., additional, Usson, Y., additional, Metzler-Guillemain, C., additional, Mignon-Ravix, C., additional, Mitchell, M. J., additional, Megarbane, A., additional, Sarda, P., additional, Sirma, H., additional, Moncla, A., additional, Feunteun, J., additional, and Mattei, M.-G., additional

Published
2006
Full Text
View/download PDF

38. Application of confocal laser microscopy and three‐dimensional Voronoi diagrams for volume and surface estimates of interphase chromosomes

Author

EILS, R., primary, BERTIN, E., additional, SARACOGLU, K., additional, RINKE, B., additional, SCHRÖCK, E., additional, PARAZZA, F., additional, USSON, Y., additional, ROBERT‐NICOUD, M., additional, STELZER, E. H. K., additional, CHASSERY, J.‐M., additional, CREMER, T., additional, and CREMER, C., additional

Published
1995
Full Text
View/download PDF

45. Quantitative comparison of polar approach versus fitting method in time domain FLIM image analysis.

Author

Leray, A., Spriet, C., Trinel, D., Blossey, R., Usson, Y., and Héliot, L.

Abstract

We calculate here analytically the performance of the polar approach (or phasor) in terms of signal-to-noise ratio and F values when performing time-domain Fluorescence Lifetime Imaging Microscopy (FLIM) to determine the minimal number of photons necessary for FLIM measurements (which is directly related to the F value), and compare them to those obtained from a well-known fitting strategy using the Least Square Method (LSM). The importance of the fluorescence background on the lifetime measurement precision is also investigated. We demonstrate here that the LSM does not provide the best estimator of the lifetime parameter for fluorophores exhibiting mono-exponential intensity decays as soon as fluorescence background is superior to 5%. The polar approach enables indeed to determine more precisely the lifetime values for a limited range corresponding to usually encountered fluorescence lifetime values. These theoretical results are corroborated with Monte Carlo simulations. We finally demonstrate experimentally that the polar approach allows distinguishing in living cells two fluorophores undetectable with usual time-domain LSM fitting software. © 2010 International Society for Advancement of Cytometry [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

47. Metabolic consequences of functional complexes of mitochondria, myofibrils and sarcoplasmic reticulum in muscle cells.

Author

Andrienko, T., Kuznetsov, A.V., Kaambre, T., Usson, Y., Orosco, A., Appaix, F., Tiivel, T., Sikk, P., Vendelin, M., Margreiter, R., and Saks, V.A.

Subjects
MUSCLE cells, MITOCHONDRIA, SARCOPLASMIC reticulum
Abstract

Regulation of mitochondrial respiration both by endogenous and exogenous ADP in the cells in situ was studied in isolated and permeabilized cardiomyocytes, permeabilized cardiac fibers and 'ghost' fibers (all with a diameter of 10-20 µm) at different (0-3 µmol 1[sup -1]) free Ca[sup 2+] concentrations in the medium. In all these preparations, the apparent K[sub m] of mitochondrial respiration for exogenous ADP at free Ca[sup 2+] concentrations of 0-0.1 µmol l[sup -1] was very high, in the range of 250-350 µmol 1[sup -1], in contrast to isolated mitochondria in vitro (apparent K[sub m] for ADP is approximately 20 µmol l[sup -1]). An increase in the free Ca[sup 2+] concentration (up to 3 µmol l[sup -1], which is within physiological range), resulted in a very significant decrease of the apparent K[sub m] value to 20-30 µmol l[sup -1], a decrease of V[sub max] of respiration in permeabilized intact fibers and a strong contraction of sarcomeres. In ghost cardiac fibers, from which myosin was extracted but mitochondria were intact, neither the high apparent K[sub m] for ADP (300-350 µmol 1[sup -1]) nor V[sub max] of respiration changed in the range of free Ca[sup 2+] concentration studied, and no sarcomere contraction was observed. The exogenous-ADP-trapping system (pyruvate kinase + phosphoenolpyruvate) inhibited endogenous-ADP-supported respiration in permeabilized cells by no more than 40%, and this inhibition was reversed by creatine due to activation of mitochondrial creatine kinase. These results are taken to show strong structural associations (functional complexes) among mitochondria, sarcomeres and sarcoplasmic reticulum. Inside these complexes, mitochondrial functional state is controlled by channeling of ADP, mostly via energy- and phosphoryltransfer networks, and apparently depends on the state of sarcomere structures. [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

48. Improvement of FISH mapping resolution on combed DNA molecules by iterative constrained deconvolution: a quantitative study.

Author

Monier, K., Heliot, L., Rougeulle, C., Heard, E., Robert-Nicoud, M., Vourc'h, C., Bensimon, A., and Usson, Y.

Subjects
IMAGE reconstruction, DNA, MOLECULES, FLUORESCENCE, FISH as laboratory animals, MICROSCOPY
Abstract

Image restoration approaches, such as digital deconvolution, are becoming widely used for improving the quality of microscopic images. However, no quantification of the gain in resolution of fluorescence images is available. We show that, after iterative constrained deconvolution, fluorescent cosmid signals appear to be 25% smaller, and 1.2-kb fragment signals on combed molecules faithfully display the expected length. Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Published
2001
Full Text
View/download PDF

50. Quantification of cardiomyocyte contraction based on image correlation analysis

Author

Kamgoué, A., Ohayon, J., Usson, Y., Riou, L., and Tracqui, P.

Abstract

Quantification of cardiomyocyte contraction is usually obtained by measuring globally cell shortening from the displacement of cell extremities. We developed a correlationbased optical flow method, which correlates the wholecell temporal pattern with a precise quantification of the intracellular strain wave at the sarcomeres level. A twodimensional image correlation analysis of cardiomyocytes phasecontrast images was developed to extract local cell deformations from videomicroscopy timelapse sequences. Test images, synthesized from known intensity displacement fields, were first used to validate the method. Intracellular strain fields were then computed from videomicroscopy timelapse sequences of single adult and neonatal cardiomyocytes. The propagation of the sarcomeres contraction–relaxation wave during cell contraction has been successfully quantified. The timevarying patterns of intracellular displacement were obtained accurately, even when cardiomyocyte bending occurred in pace with contraction. Interestingly, the characterization of the successive 2D displacement fields show a direct quantification of the variation with time of intracellular strains anywhere in the cell. The proposed method enables a quantitative analysis of cardiomyocyte contraction without requiring wave tracking with the use of fluorescent calcium probes. Thus, our algorithmic approach provides a fast and efficient tool for analyzing the correlation between global cell dynamical behavior and mechanosensitive intracellular processes. © 2008 International Society for Advancement of Cytometry

Published
2009
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results