Philippe JEAN-PIERRE

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• Type de publi. : Article dans une revue
• Date de publi. : 01/06/2004
• Auteurs : Pierre H. ManginPhilippe OhlmannAnita EcklyJean-Pierre CazenaveFrançois LanzaChristian Gachet
• Organismes : Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg] Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg] Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg] Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg] Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg] Biologie et pharmacologie de l'hémostase et de la thrombose Établissement Français du Sang Grand-Est [Strasbourg]
• Publié dans Journal of Thrombosis and Haemostasis le 27/10/2020

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Résumé : ADP and TxA2 are secondary agonists which play an important role as cofactors when platelets are activated by agonists such as collagen or thrombin. The aim of the present study was to characterize the role of the ADP receptor P2Y(1) in collagen-induced activation of washed platelets. Inhibition of P2Y(1) alone with the selective antagonist MRS2179 prolonged the lag phase preceding aggregation in response to low or high concentrations of fibrillar collagen, without affecting the maximum amplitude of aggregation or secretion. A combination of MRS2179 and aspirin resulted in complete inhibition of platelet shape change at low and high collagen concentrations, together with a profound decrease in aggregation and secretion. Scanning electron microscopy showed that these platelets had conserved the discoid morphology typical of the resting state. A lack of shape change was also observed in aspirin-treated P2Y(1)- and G(alphaq)-deficient mouse platelets and in delta-storage pool-deficient platelets from Fawn Hooded rats. In contrast, when the second ADP receptor P2Y(12) was inhibited with AR-C69931MX, aspirin-treated platelets were still able to change shape and displayed only a moderate decrease in aggregation and secretion. In conclusion, this study provides evidence that collagen requires not only the TxA2 receptor Tpalpha, but also P2Y(1), to induce platelet shape change.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/06/2004
• Auteurs : Damien ChablatPhilippe WengerFélix MajouJean-Pierre Merlet
• Organismes : Institut de Recherche en Communications et en Cybernétique de Nantes Institut de Recherche en Communications et en Cybernétique de Nantes Institut de Recherche en Communications et en Cybernétique de Nantes Constraints solving, optimization and robust interval analysis
• Publié dans The International Journal of Robotics Research le 01/11/2020

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Résumé : This paper addresses an interval analysis based study that is applied to the design and the comparison of 3-DOF parallel kinematic machines. Two design criteria are used, (i) a regular workspace shape and, (ii) a kinetostatic performance index that needs to be as homogeneous as possible throughout the workspace. The interval analysis based method takes these two criteria into account: on the basis of prescribed kinetostatic performances, the workspace is analysed to find out the largest regular dextrous workspace enclosed in the Cartesian workspace. An algorithm describing this method is introduced. Two 3-DOF translational parallel mechanisms designed for machining applications are compared using this method. The first machine features three fixed linear joints which are mounted orthogonally and the second one features three linear joints which are mounted in parallel. In both cases, the mobile platform moves in the Cartesian x-y-z space with fixed orientation.

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Fichiers liés : IJRR_bis_Chablat_Wenger_Majou_Merlet.pdf

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• Type de publi. : Communication dans un congrès
• Date de publi. : 17/05/2004
• Auteurs : William S. KurthDonald A. GurnettJohn T. ClarkeM. DeschMichael L. KaiserPhilippe ZarkaBaptiste CecconiAlain LecacheuxPatrick H. M. GalopeauJean-Claude GérardD. C. GrodentMichele K. DoughertyFrank J. Crary
• Organismes : Laboratoire d'études spatiales et d'instrumentation en astrophysique Physique des plasmas Laboratoire d'études spatiales et d'instrumentation en astrophysique Physique des plasmas Laboratoire d'études spatiales et d'instrumentation en astrophysique Physique des plasmas

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• Type de publi. : Article dans une revue
• Date de publi. : 15/05/2004
• Auteurs : Sébastien DuleuPhilippe VincendeauPierrette CourtoisSilla SemballaIsabelle LagroyeSylvie DaulouèdeJean-Luc BoucherKeith WilsonBernard VeyretAlain Gobert
• Organismes : Université de Bordeaux
• Publié dans Journal of Immunology le 27/10/2020

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Résumé : Abstract We previously reported that macrophage arginase inhibits NO-dependent trypanosome killing in vitro and in vivo. BALB/c and C57BL/6 mice are known to be susceptible and resistant to trypanosome infection, respectively. Hence, we assessed the expression and the role of inducible NO synthase (iNOS) and arginase in these two mouse strains infected with Trypanosoma brucei brucei. Arginase I and arginase II mRNA expression was higher in macrophages from infected BALB/c compared with those from C57BL/6 mice, whereas iNOS mRNA was up-regulated at the same level in both phenotypes. Similarly, arginase activity was more important in macrophages from infected BALB/c vs infected C57BL/6 mice. Moreover, increase of arginase I and arginase II mRNA levels and of macrophage arginase activity was directly induced by trypanosomes, with a higher level in BALB/c compared with C57BL/6 mice. Neither iNOS expression nor NO production was stimulated by trypanosomes in vitro. The high level of arginase activity in T. brucei brucei-infected BALB/c macrophages strongly inhibited macrophage NO production, which in turn resulted in less trypanosome killing compared with C57BL/6 macrophages. NO generation and parasite killing were restored to the same level in BALB/c and C57BL/6 macrophages when arginase was specifically inhibited with Nω-hydroxy-nor-l-arginine. In conclusion, host arginase represents a marker of resistance/susceptibility to trypanosome infections.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/05/2004
• Auteurs : Véronique JanPascale CerveraMustapha MaachiMarielle BaudrimontMin Ji KimHubert VidalPierre-Marie GirardPhilippe LevanWilly RozenbaumAnne LombèsJacqueline CapeauJean-Philippe Bastard
• Organismes : Pathologie de l'Adipocyte et des Cellules Hepatiques
• Publié dans Antiviral Therapy le 24/10/2020

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Résumé : Objective To achieve a better understand of the pathophysiology of HIV-related lipoatrophy, we compared the mRNA expression of adipocytokines in fat samples from patients and healthy HIV-seronegative controls together with fat morphology and we studied the relationship between changes in fat morphology, adipocytokine expression, markers of adipose tissue differentiation and whole body insulin sensitivity. Design Cross-sectional analytical study. Subjects and methods The mRNA expression of adipocytokines and transcriptional factors in fat samples from 26 patients with peripheral lipoatrophy (all under anti-retroviral therapy associating protease inhibitor and nucleoside-analogue reverse transcriptase inhibitors) and from 16 non-HIV-infected controls was measured by real time quantitative RT-PCR. Fat morphology was assessed histologically on a subgroup of 10 patients and six controls: collagen fibres by Sirius Red staining, apoptosis by the TUNEL technique, vessels by smooth muscle α-actin staining and macrophages by CD68 staining. Insulin resistance was assessed by using the homeostasis model assessment. Results The patients’ fat showed higher values of apoptosis ( P=0.005), fibrosis ( P<0.05), vessel density ( P=0.001) and macrophage infiltration ( P<0.05) than the controls’ fat, together with lower adiponectin and leptin mRNA levels and higher interleukin (IL)-6 and tumour necrosis factor (TNF)α mRNA levels. TNFα and IL-6 expression correlated positively with the level of apoptosis ( P=0.05 and P<0.05, respectively) and negatively with CCAAT-enhancer binding protein (C/EBP)α ( P<0.001 and P<0.05, respectively). Apoptosis correlated negatively with the expression level of sterol-regulatory-element-binding-protein-1c (SREBP1c) ( P=0.01) and C/EBPα ( P=0.01) whilst the vessel density correlated negatively with SREBP1c ( P<0.005), C/EBPα ( P=0.001) and β ( P=0.001). Adiponectin and leptin expression correlated positively with each other, and also with adipogenic marker expression and overall insulin sensitivity. These relationships were also present when the patient group was studied separately. Finally, fat morphological abnormalities correlated positively with whole body insulin resistance. Conclusions Adipose tissue from patients with HIV-1-related lipoatrophy shows increased apoptosis, together with decreased adipocyte differentiation. Increased TNFα and IL-6 expression could be a major phenomenon linking these alterations. Decreased adiponectin and leptin expression, which may result from decreased adipocyte differentiation, could be involved in the observed whole body insulin resistance.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/05/2004
• Auteurs : Severine GuilbertThierry SauvagePhilippe GarciaGaelle CarlotMarie-France BarthePierre DesgardinGilbert BlondiauxCatherine CorbelJean-Paul PironJean-Marie Gras
• Organismes : Centre d'Études et de Recherches par Irradiation Conditions Extrêmes et Matériaux : Haute Température et Irradiation Laboratoire de Modélisation Multi-échelles des Combustibles Conditions Extrêmes et Matériaux : Haute Température et Irradiation Conditions Extrêmes et Matériaux : Haute Température et Irradiation Conditions Extrêmes et Matériaux : Haute Température et Irradiation Laboratoire des Solides Irradiés - Irradiated Solids Laboratory CEA Cadarache EDF – Électricité de France
• Publié dans Journal of Nuclear Materials le 25/10/2020

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Résumé : The behaviour of helium implanted in sintered uranium dioxide disks has been investigated as a function of annealing temperature. UO2 disks have been implanted with 1 MeV 3He ions at a fluence of 1 × 1016 3He cm−2 using a Van der Graaff accelerator. These implantation conditions lead to a local helium concentration of 0.2 at.% at a depth of 1.9 μm in UO2. The 3He(d,α)1H Nuclear Reaction Analysis method was used to determine the helium depth profile after the various annealing stages. The experimental results measured after 1100 °C anneal were analysed using a simple model which satisfactorily reproduces the observed helium depth profile changes. The intragranular helium diffusion coefficient is estimated and the result is assessed against other data published in the open literature.

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• Type de publi. : Rapport
• Date de publi. : 01/05/2004
• Auteurs : Olivier C FaugerasGeoffray AddeGuillaume CharpiatChristophe Chefd'HotelMaureen ClercThomas DeneuxRachid DericheGerardo HermosilloRenaud KerivenPierre KornprobstJan KybicChristophe LengletLucero Lopez-PerezThéodore PapadopouloJean-Philippe PonsFlorent SegonneBertrand ThirionDavid TschumperléThierry ViévilleNicolas Wotawa
• Organismes : Computer and biological vision

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Résumé : We survey the recent activities of the Odyssée Laboratory in the area of the application of mathematics to the design of models for studying brain anatomy and function. We start with the problem of reconstructing sources in MEG and EEG and discuss the variational approach we have developed for solving these inverse problems. This motivates the need for geometric models of the head. We present a method for automatically and accurately extracting surface meshes of several tissues of the head from anatomical MR images. Anatomical connectivity can be extracted from Diffusion Tensor Magnetic Resonance Images but, in the current state of the technology, it must be preceded by a robust estimation and regularization stage. We discuss our work based on variational principles and show how the results can be used to track fibers in the white matter as geodesics in some Riemannian space. We then go to the statistical modeling of fMRI signals from the viewpoint of their decomposition in a pseudo-deterministic and stochastic part which we then use to perform clustering of voxels in a way that is inspired by the theory of Support Vector Machines and in a way that is grounded in information theory. Multimodal image matching is discussed next in the framework of image statistics and Partial Differential Equations with an eye on registering fMRI to the anatomy. The paper ends with a discussion of a new theory of random shapes that may prove useful in building anatomical and functional atlases.

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Fichiers liés : RR-5202.pdf

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• Type de publi. : Article dans une revue
• Date de publi. : 01/05/2004
• Auteurs : Nadège PhilippeJean-Pierre AlcarazEvelyne CoursangeJohannes GeiselmannDominique Schneider
• Organismes : Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] Plastes et différenciation cellulaire Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] Université Joseph Fourier - Grenoble 1 Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] Université Joseph Fourier - Grenoble 1
• Publié dans Plasmid le 02/11/2020

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Résumé : Allelic exchange experiments allow investigation of the functions of many unknown genes identified during the sequencing of entire genomes. Isogenic strains differing by only specific mutations can be constructed. Among other tools, suicide plasmids are widely used for this task. They present many advantages because they leave no scars on the chromosome, and therefore allow combining several mutations in the same genetic background. While using the previously described pCVD442 suicide plasmid [Infect. Immun. 59 (1991) 4310], we found untargeted recombination events due to the presence of an IS1 element on this plasmid. The plasmid was therefore improved by removal of the IS1 element. We also replaced the bla gene of pCVD442, conferring ampicillin resistance, by the cat gene conferring chloramphenicol resistance, leading to the new suicide plasmid pDS132. The plasmid was entirely sequenced. We demonstrate that this new vector can be easily used to introduce various types of mutations into different genetics backgrounds: removal of IS elements, introduction of point mutations or deletions. It can be introduced into bacterial strains by either transformation or conjugation.

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• Type de publi. : Article dans une revue
• Date de publi. : 01/05/2004
• Auteurs : Fouzia BoulmedaisBenoit FrischOlivier EtiennePhilippe LavalleCatherine PicartJoelle OgierJean-Claude VoegelPierre SchaafChristophe Egles
• Organismes : Institut Charles Sadron Biomatériaux : Processus biophysiques et biologiques aux interfaces Laboratoire de chimie bioorganique Biomatériaux : Processus biophysiques et biologiques aux interfaces Biomatériaux : Processus biophysiques et biologiques aux interfaces Biomatériaux : Processus biophysiques et biologiques aux interfaces École Européene de Chimie, Polymères et Matériaux [Strasbourg] Biomatériaux : Processus biophysiques et biologiques aux interfaces Biomatériaux : Processus biophysiques et biologiques aux interfaces Institut Charles Sadron École Européene de Chimie, Polymères et Matériaux [Strasbourg] Biomatériaux : Processus biophysiques et biologiques aux interfaces
• Publié dans Biomaterials le 28/10/2020

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Résumé : Adhesion of bacteria at the surface of implanted materials is the first step in microbial infection, leading to post-surgical complications. In order to reduce this adhesion, we show that poly(L-lysine)/poly(L-glutamic acid) (PLL/PGA) multilayers ending by several PLL/PGA-g-PEG bilayers can be used, PGA-g-PEG corresponding to PGA grafted by poly(ethylene glycol). Streaming potential and quartz crystal microbalance-dissipation measurements were used to characterize the buildup of these films. The multilayer films terminated by PGA and PGA-g-PEG were found to adsorb an extremely small amount of serum proteins as compared to a bare silica surface but the PGA ending films do not reduce bacterial adhesion. On the other hand, the adhesion of Escherichia coli bacteria is reduced by 72% on films ending by one (PLL/PGA-g-PEG) bilayer and by 92% for films ending by three (PLL/PGA-g-PEG) bilayers compared to bare substrate. Thus, our results show the ability of PGA-g-PEG to be inserted into multilayer films and to drastically reduce both protein adsorption and bacterial adhesion. This kind of anti-adhesive films represents a new and very simple method to coat any type of biomaterials for protection against bacterial adhesion and therefore limiting its pathological consequences.

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• Type de publi. : Communication dans un congrès
• Date de publi. : 01/05/2004
• Auteurs : Laurence Goux-CapesArianna FiloramoDenis CôteEmmanuel ValentinJean-Philippe BourgoinJean-Noël Patillon
• Organismes : Laboratoire d'Electronique Moléculaire Laboratoire d'Electronique Moléculaire Laboratoire Pierre Aigrain Laboratoire d'Electronique Moléculaire Laboratoire d'Electronique Moléculaire Laboratoire d'Electronique Moléculaire

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Résumé : Single wall carbon nanotubes (SWNTs) occupy a special place within molecular electronics. Indeed, they exist as semiconducting or metallic wires and have been used to demonstrate molecular devices like transistors, diodes or SET (single electron transistor). However, the future of this class of SWNT-based devices is strictly related to the development of a bottom-up self-assembly technique. The exceptional recognition properties of DNA molecule make it an ideal candidate for this task. Here, we describe a non-covalent method to connect carbon nanotubes to DNA strands using the streptavidin/biotin complex. Control experiments show that in absence of biotin, the DNA strand do not bind to SWNT. The binding of SWNT to DNA strand has also been carefully checked by washing experiments, showing the strength of the DNA anchorage on SWNTs. Combining this approach with molecular combing enable us to align nanotubes on substrate.

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