Philippe JEAN-PIERRE

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/12/1998
• Auteurs : Danielle Casset-SenonPhilippe LaurentDominique BabutyVéronique EderLaurent FauchierJean Paul FauchierJean Marie PottierPierre Cosnay
• Organismes : Centre Hospitalier Régional Universitaire de Tours Pôle Santé Léonard de Vinci Centre Hospitalier Régional Universitaire de Tours Centre Hospitalier Régional Universitaire de Tours CHU Trousseau [Tours] Centre Hospitalier Régional Universitaire de Tours
• Publié dans American Journal of Cardiology le 22/10/2020

---

Résumé : To evaluate the diagnostic performance of Fourier phase analysis of gated blood pool single-photon emission computed tomography (GBP SPECT) in arrhythmogenic right ventricular (RV) cardiomyopathy, 18 patients with confirmed arrhythmogenic RV cardiomyopathy underwent GBP SPECT and x-ray cineangiography. Results were compared with data obtained with GBP SPECT in 10 control subjects. This 3-dimensional method demonstrated good correlation with cineangiography for measurements of RV enlargement and extent of the disease; RV and left ventricular segments were analyzed with the same accuracy. Tomographic abnormalities were significant decreased RV ejection fraction, RV dilatation, nonsynchronized contraction of the ventricles, increased RV contraction dispersion, presence of segmental RV wall motion disorders and/or phase delays, and occasionally regional left ventricular abnormalities. RV-delayed phase areas were always present in our population. A scoring system with RV criteria was proposed to diagnose RV disease. Because Fourier analysis of GBP SPECT provides ventricular morphologic information for the right ventricle with the same accuracy as for the left ventricle, it may replace planar radionuclide studies. Therefore, this method is helpful in patients with a strong clinical suspicion of arrhythmogenic RV cardiomyopathy, and should be used as a screening method before right ventriculography.

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/12/1998
• Auteurs : Beatrice HechlerAnita Eckly-MichelPhilippe OhlmannJean-Pierre CazenaveChristian Gachet
• Organismes :
• Publié dans British Journal of Haematology le 29/10/2020

---

Résumé : Recently we showed that the P2Y1 receptor coupled to calcium mobilization is necessary to initiate ADP-induced human platelet aggregation. Since the thienopyridine compound clopidogrel specifically inhibits ADP-induced platelet aggregation, it was of interest to determine whether the P2Y1 receptor was the target of this drug. Therefore we studied the effects of clopidogrel and of the two specific P2Y1 antagonists A2P5P and A3P5P on ADP-induced platelet events in rats. Although clopidogrel treatment (50 mg/kg) greatly reduced platelet aggregation in response to ADP as compared to untreated platelets, some residual aggregation was still detectable. In contrast, A2P5P and A3P5P totally abolished ADP-induced shape change and aggregation in platelets from both control and clopidogrel-treated rats. A2P5P and A3P5P (100 microM) totally inhibited the [Ca2+]i rise induced by ADP (0.1 microM) in control and clopidogrel-treated platelets, whereas clopidogrel treatment had no effect. Conversely, the inhibition of adenylyl cyclase induced by ADP (5 microM) was completely blocked by clopidogrel but not modified by A2P5P or A3P5P (100 microM). A3P5P (1 mM) reduced the number of [33P]2MeSADP binding sites on control rat platelets from 907 +/- 50 to 611 +/- 25 per platelet. After clopidogrel treatment, binding of [33P]2MeSADP decreased to 505 +/- 68 sites per platelet and further decreased to 55 +/- 12 sites in the presence of A3P5P (1 mM). In summary, these results demonstrate that the platelet P2Y1 receptor responsible for the initiation of aggregation in response to ADP is not the target of clopidogrel. Platelets may express another, as yet unidentified, P2Y receptor, specifically coupled to the inhibition of adenylyl cyclase and necessary to induce full platelet aggregation, which could be the target of this drug.

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/12/1998
• Auteurs : Pierre-André VuissozJean-Philippe AnsermetAndrzej Wieckowski
• Organismes : Ecole Polytechnique Fédérale de Lausanne
• Publié dans Electrochimica Acta le 02/11/2020

---

Source

---

• Type de publi. : Communication dans un congrès
• Date de publi. : 16/11/1998
• Auteurs : Jean-Claude DesportPierre-Marie PreuxCt TruongJean-Michel VallatD SautereauPhilippe Couratier
• Organismes : Neuroépidémiologie Tropicale et Comparée Service d'Hépato-gastro-entérologie et Nutrition [CHU Dupuytren 1, Limoges] Neuroépidémiologie Tropicale et Comparée Service de Neurologie [CHU Limoges] Service de l'Information Médicale et de l'Évaluation [CHU Limoges] Laboratoire de Biostatistique et d'Informatique Médicale Centre de référence national neuropathies périphériques rares [CHU Limoges] Service de Neurologie [CHU Limoges] Neuroépidémiologie Tropicale et Comparée Service de Neurologie [CHU Limoges]

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/10/1998
• Auteurs : Laurent FauchierDominique BabutyMarie Laurence AutretPhilippe PoretPierre CosnayJean Paul Fauchier
• Organismes : CHU Trousseau [Tours] Centre Hospitalier Régional Universitaire de Tours Centre Hospitalier Régional Universitaire de Tours
• Publié dans Cardiovascular Drugs and Therapy le 29/10/2020

---

Résumé : Heart rate variability is a noninvasive indicator of autonomic nervous system activity. The role of the autonomic nervous system in the genesis of atrial or ventricular arrhythmias is now well established. Little is known about the effects of flecainide on heart rate variability in patients with normal heart structure, the main population receiving flecainide. This study was designed to evaluate the effects of flecainide on heart rate variability in patients without coronary artery disease or congestive heart failure. Time and frequency domain analysis of heart rate variability on 24-hour electrocardiogram recording were assessed in 40 patients with normal echocardiography and without evidence of coronary artery disease before and after 2 months of oral treatment with flecainide (321 +/- 57 mg/day) prescribed for Wolff Parkinson White syndrome with circus movement tachycardia. Flecainide significantly decreased all parameters of heart rate variability in the time domain (median delta% -10% to -25%) and in the frequency domain (median delta% -27% to -38%), including the markers of vagal activity. There was no correlation between plasma concentrations of flecainide and reduction in heart rate variability. It was concluded that in subjects without coronary artery disease or congestive heart failure, flecainide decreases all the measurements of heart rate variability and this decrease is not related to plasma concentrations of flecainide.

---

Source

---

• Type de publi. : Communication dans un congrès
• Date de publi. : 01/10/1998
• Auteurs : Stéphane RossignolXavier RodetJoel SoumagneJean-Louis ColettePhilippe Depalle
• Organismes : Analyse et synthèse sonores [Paris] Analyse et synthèse sonores [Paris] Analyse et synthèse sonores [Paris] Analyse et synthèse sonores [Paris] Analyse et synthèse sonores [Paris]

---

Résumé : This paper deals with temporal segmentation of acoustic signals and feature extraction. Segmentation and feature extraction are aimed at being a first step for sound signal representation, coding, transformation and multimedia. Three interdependent levels of segmentation are defined. They correspond to different levels of signal attributes. The Source level distinguishes speech, singing voice, instrumental parts and other sounds, such as street sounds, machine noise... The Feature level deals with characteristics such as silence/sound, transitory/steady, voiced/unvoiced, harmonic, vibrato and so forth. The last level is the segmentation into Notes and Phones. A large set of features is first computed: derivative and relative derivative of f0 and energy, voicing coefficient, mesure of the inharmonicity of the partials, spectral centroid, spectral ``flux'', high order statistics, energy modulation, etc. A decision function on the set of features has been built and provides the segmentation marks. It also depends on the current application and the required result. As an example, in the case of the singing voice, segmentation according to pitch is different from segmentation into phones. A graphical interface allows visualization of these features, the results of the decisions, and the final result. For the Source level, some features are predominant: spectral centroid, spectral flux, energy modulation and their variance computed on a sound segment of one second or more. Segmentation starts with the Source level, but the three levels are not independent. Therefore, information obtained at a given level is propagated towards the other levels. For example, in case of instrumental music and the singing voice, if vibrato is detected at the Feature level, amplitude and frequency of the vibrato are estimated and are taken into account for the Notes and Phones level. The vibrato is removed from the f0 trajectory, and the high frequencies of the signal are not used in spectral flux computation. A complete segmentation and feature extraction system is demonstrated. Applications and results on various examples such as a movie sound track are presented.

---

Fichiers liés : index.pdf

---

Source

---

• Type de publi. : Communication dans un congrès
• Date de publi. : 01/10/1998
• Auteurs : André ChanzyChristine KingLaurent PrevotAgnès RemondWigneron J.-P.Philippe CalcagnoZribi MehrezJean-François Desprats
• Organismes : Unité de Science du Sol Bureau de Recherches Géologiques et Minières Unité de Science du Sol Bureau de Recherches Géologiques et Minières Unité de bioclimatologie Bureau de Recherches Géologiques et Minières Centre d'étude des environnements terrestre et planétaires Bureau de Recherches Géologiques et Minières

---

Résumé : The combined use of ERS and multiangle RADARSAT (23 and 38°) data to assess the soil moisture, the roughness and the soil surface degradation is investigated. Twenty SAR images were collected over a flat agricultural area located near Avignon in the South-East of France. Complementary sets of data, collected with the CNES ground based scatterometer RAMSES and IEM simulations were also used in the analysis. Results show that the soil surface roughness affects strongly the s0-qs relation. But the roughness influence cannot be easily accounted for using the IEM model. From the RAMSES data, we demonstrate that the angular difference of the backscattering coefficient is a very good indicator to track the evolution of the soil surface degradation. Such a result is confirmed by RADARSAT couple (23-38°) measurements on the first development stages of sunflower crops.

---

Fichiers liés : Chanzy&Al._at_Estec98.pdf

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/10/1998
• Auteurs : Djamel KhadraouiChristophe DebainPhilippe MartinetPierre BontonJean Gallice
• Organismes : Laboratoire des sciences et matériaux pour l'électronique et d'automatique Technologies et systèmes d'information pour les agrosystèmes Centre national du machinisme agricole, du génie rural, des eaux et forêts Laboratoire des sciences et matériaux pour l'électronique et d'automatique Laboratoire des sciences et matériaux pour l'électronique et d'automatique Systèmes Microélectroniques et Traitement d'Images Laboratoire des sciences et matériaux pour l'électronique et d'automatique
• Publié dans The International Journal of Robotics Research le 01/11/2020

---

Résumé : This article presents a real-time control system for an agricultural mobile machine (vehicle) based on an on-board vision system using a single camera. This system has been designed in order to help human beings in repetitive and di cult tasks in the agricultural domain. The aim of the robotics application concerns the control of the vehicle with regard to the reap limit detected in image space. The perception aspect in relation with the application has been described in previous work, and here we deal with the control aspect. We integrate image features issued from the modelling of the scene in the control loop, in order to perform image-based servoing technique. The vehicle behaviour described here concerns bicycle and neural models, and three control laws are then synthesized. The rst and the second are modelling approaches and use an interaction between the scene and the image space. They are based on regulation of a task function. The third is a \black-box modelling" technique and is based on a neural network. Finally, experimental results obtained with these di erent control laws in different conditions are presented and discussed.

---

Fichiers liés : ijrr97.pdf

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/09/1998
• Auteurs : Philippe LahayeKhalid TaziJean-Pierre RonaOlivier DellisDidier LebrecRichard Moreau
• Organismes : Université Denis Diderot Ampère, Département Méthodes pour l'Ingénierie des Systèmes Ampère, Département Automatique pour l'Ingénierie des Systèmes
• Publié dans Hepatology le 30/10/2020

---

Résumé : Protein kinase C (PKC) modulates the activity and phosphorylation of the catalytic α-subunit of sodium-potassium-adenosine triphosphatase (Na + /K + ATPase) in normal arteries. Because PKC is altered in cirrhotic aortae, Na + /K + ATPase may also be altered in these arteries. The aim of the present study was to investigate α-subunit activity and phosphorylation in aortae from normal and cirrhotic rats, under baseline conditions and during exposure to PKC modulators. α-Subunit activity was assessed by measuring the amount of 32 P released by hydrolysis of [γ- 32 P]ATP in freshly isolated cell membranes (in the absence of PKC modulators only) and membrane depolarization caused by ouabain-induced α-subunit inhibition in isolated aortae (in the absence and presence of PKC modulators). α-Subunit phosphorylation was assessed by incorporation of 32 P into α-subunits. Staurosporine, a PKC inhibitor, and phorbol 12,13-dibutyrate (PDBU), a PKC activator, were used. In addition, α-subunit expression was studied by Western blot analysis. In the absence of PKC modulators, the amount of 32 P released by hydrolysis of [γ- 32 P]ATP and ouabain-induced membrane depolarization were significantly lower in cirrhotic than in normal aortae. Staurosporine suppressed ouabain-induced membrane depolarization in cirrhotic and normal arteries. Ouabain-induced membrane depolarization was similar in cirrhotic aortae exposed to PDBU and in normal arteries studied under baseline conditions. α-Subunit phosphorylation was significantly lower in cirrhotic than in normal aortae, in aortae under baseline conditions, and in arteries exposed to staurosporine. Phosphorylation of the α-subunit was similar in cirrhotic aortae exposed to PDBU and in normal arteries under baseline conditions. Western blot analysis showed that the amount of α-subunit did not significantly differ between cirrhotic and normal aortae. In conclusion, a decrease in baseline Na + /K + ATPase α-subunit activity occurs in aortae from cirrhotic rats as a result of reduced basal PKC activity. This PKC-dependent decreased α-subunit activity may be caused by a reduction in PKC-induced α-subunit phosphorylation.

---

Source

---

• Type de publi. : Article dans une revue
• Date de publi. : 01/09/1998
• Auteurs : Olivier ValdenaireMarion Maus-MoattiJean-Didier VincentJacques MalletPhilippe Vernier
• Organismes : F. Hoffmann-La Roche [Basel] Laboratoire de Génétique Moléculaire de la Neurotransmission et des Processus Neurodégénératifs [APHP Pitié-Salpêtrière] Collège de France - Chaire Neuropharmacologie Institut de Neurobiologie Alfred Fessard Laboratoire de Génétique Moléculaire de la Neurotransmission et des Processus Neurodégénératifs [APHP Pitié-Salpêtrière] Institut de Neurobiologie Alfred Fessard
• Publié dans Journal of Neurochemistry le 25/10/2020

---

Résumé : The time course of D2 receptor expression assessed by the levels of the corresponding binding sites and mRNA was studied in rat striatum during ontogenesis and in primary cultures of cells taken at embryonic day (E) 17 and postnatal day (P) 4. In the two experimental situations, the amount of D2 receptor mRNA and number of binding sites increased regularly from E16 to P15, indicating that expression of D2 receptors in striatal neurons occurs independently from a dopaminergic input. Incubation of striatal primary cultures with 10(-5) M retinoic acid significantly increased the level of D2 receptor mRNA, whereas thyroid hormone, vitamin D3, and steroid hormones (estradiol, testosterone, and corticosterone) had no effect. The transcriptional activity of the rat D2 receptor gene promoter region, which bears a retinoic acid-responsive element, was increased by retinoic acid in transfected C6 glioma cells but not in transfected MMQ prolactin cells. Thyroid hormone and vitamin D3 were not effective in either cell line. Finally, mutations of the putative retinoic acid-responsive element inhibited the transcriptional effect of retinoic acid. These results suggest that retinoic acid is a key factor in regulation of the embryonic onset of the dopaminergic D2 receptor.

---

Source