Simulation de champs aléatoires invariants par rotation et homothétie

La notion de texture aléatoire est associée à la notion de stationnarité, donc d'invariance par translation. Or tous les modèles de texture connus ne sont pas stationnaires. Dans cet article, la notion plus générale d'invariance au second ordre pour un ensemble de transformations planes est étudiée. On s'intéresse en particulier à l'invariance par homothétie et par rotation d'un centre fixé. Pour la simulation de champs possédant cette invariance on propose la méthode du krigeage. On étudie théoriquement l'erreur de corrélation induite par la méthode de simulation

Autoantibodies to Endothelial Cell Surface ATP Synthase, the Endogenous Receptor for Hsp60, Might Play a Pathogenic Role in Vasculatides

International audienceBACKGROUND: Heat shock protein (hsp) 60 that provides "danger signal" binds to the surface of resting endothelial cells (EC) but its receptor has not yet been characterized. In mitochondria, hsp60 specifically associates with adenosine triphosphate (ATP) synthase. We therefore examined the possible interaction between hsp60 and ATP synthase on EC surface. METHODOLOGY/PRINCIPAL FINDINGS: Using Far Western blot approach, co-immunoprecipitation studies and surface plasmon resonance analyses, we demonstrated that hsp60 binds to the β-subunit of ATP synthase. As a cell surface-expressed molecule, ATP synthase is potentially targeted by anti-EC-antibodies (AECAs) found in the sera of patients suffering vasculitides. Based on enzyme-linked immunosorbent assay and Western blotting techniques with F1-ATP synthase as substrate, we established the presence of anti-ATP synthase antibodies at higher frequency in patients with primary vasculitides (group I) compared with secondary vasculitides (group II). Anti-ATP synthase reactivity from group I patients was restricted to the β-subunit of ATP synthase, whereas those from group II was directed to the α-, β- and γ-subunits. Cell surface ATP synthase regulates intracellular pH (pHi). In low extracellular pH medium, we detected abnormal decreased of EC pHi in the presence of anti-ATP synthase antibodies, irrespective of their fine reactivities. Interestingly, soluble hsp60 abrogated the anti-ATP synthase-induced pHi down-regulation. CONCLUSIONS/SIGNIFICANCE: Our results indicate that ATP synthase is targeted by AECAs on the surface of EC that induce intracellular acidification. Such pathogenic effect in vasculitides can be modulated by hsp60 binding on ATP synthase which preserves ATP synthase activity

A set of invariant and stable descriptors for 3D gray-levels objects

The description of 3D objects independently of their position and orientation, is an important and difficult problem in pattern analysis. In this paper, we deal with this problem by a pseudo-Fourier transform on the group of motions of the 3D Euclidean space, which we denote by M(3). This transform allows us to define 3D gray-levels object descriptors which are invariant and stable with respect to M(3). This method is applied to human bones automatic classification and description.La description d'objets tridimensionnels indépendamment de leur position et de leur orientation est un problème important et difficile de l'analyse de formes. Dans cet article, nous traitons ce problème à l'aide d'une pseudo-transformation de Fourier sur le groupe M(3) des déplacements de l'espace euclidien à trois dimensions. Celle-ci nous permet de définir des descripteurs de volumes à niveaux de gris stables et invariants par rapport à M(3). Cette méthode est appliquée à la classification et la description automatiques d'os humains

Ultra-structural cell distribution of the melanoma marker iodobenzamide: improved potentiality of SIMS imaging in life sciences

BACKGROUND: Analytical imaging by secondary ion mass spectrometry (SIMS) provides images representative of the distribution of a specific ion within a sample surface. For the last fifteen years, concerted collaborative research to design a new ion microprobe with high technical standards in both mass and lateral resolution as well as in sensitivity has led to the CAMECA NanoSims 50, recently introduced onto the market. This instrument has decisive capabilities, which allow biological applications of SIMS microscopy at a level previously inaccessible. Its potential is illustrated here by the demonstration of the specific affinity of a melanoma marker for melanin. This finding is of great importance for the diagnosis and/or treatment of malignant melanoma, a tumour whose worldwide incidence is continuously growing. METHODS: The characteristics of the instrument are briefly described and an example of application is given. This example deals with the intracellular localization of an iodo-benzamide used as a diagnostic tool for the scintigraphic detection of melanic cells (e.g. metastasis of malignant melanoma). B16 melanoma cells were injected intravenously to C(57)BL(6)/J(1)/co mice. Multiple B16 melanoma colonies developed in the lungs of treated animals within three weeks. Iodobenzamide was injected intravenously in tumour bearing mice six hours before sacrifice. Small pieces of lung were prepared for SIMS analysis. RESULTS: Mouse lung B16 melanoma colonies were observed with high lateral resolution. Cyanide ions gave "histological" images of the cell, representative of the distribution of C and N containing molecules (e.g. proteins, nucleic acids, melanin, etc.) while phosphorus ions are mainly produced by nucleic acids. Iodine was detected only in melanosomes, confirming the specific affinity of the drug for melanin. No drug was found in normal lung tissue. CONCLUSION: This study demonstrates the potential of SIMS microscopy, which allows the study of ultra structural distribution of a drug within a cell. On the basis of our observations, drug internalization via membrane sigma receptors can be excluded

Association of Combined Anti-Ro52/TRIM21 and Anti-Ro60/SSA Antibodies With Increased Sjögren Disease Severity Through Interferon Pathway Activation

The biologic diagnosis of primary Sjögren disease (SjD) mainly relies on anti-Ro60/SSA antibodies, whereas the significance of anti-Ro52/TRIM21 antibodies currently remains unclear. The aim of this study was to characterize the clinical, serological, biologic, transcriptomic, and interferon profiles of patients with SjD according to their anti-Ro52/TRIM21 antibody status.Patients with SjD from the European PRECISESADS (n = 376) and the Brittany Diagnostic Suspicion of primitive Sjögren's Syndrome (DIApSS); (n = 146) cohorts were divided into four groups: double negative (Ro52-/Ro60-), isolated anti-Ro52/TRIM21 positive (Ro52+), isolated anti-Ro60/SSA positive (Ro60+), and double-positive (Ro52+/Ro60+) patients. Clinical information; EULAR Sjögren Syndrome Disease Activity Index, a score representing systemic activity; and biologic markers associated with disease severity were evaluated. Transcriptome data obtained from whole blood by RNA sequencing and type I and II interferon signatures were analyzed for PRECISESADS patients.In the DIApSS cohort, Ro52+/Ro60+ patients showed significantly more parotidomegaly (33.3% vs 0%-11%) along with higher β2-microglobulin (P = 0.0002), total immunoglobulin (P < 0.0001), and erythrocyte sedimentation rate levels (P = 0.002) as well as rheumatoid factor (RF) positivity (66.2% vs 20.8%-25%) compared to other groups. The PRECISESADS cohort corroborated these observations, with increased arthritis (P = 0.046), inflammation (P = 0.005), hypergammaglobulinemia (P < 0.0001), positive RF (P < 0.0001), leukopenia (P = 0.004), and lymphopenia (P = 0.009) in Ro52+/Ro60+ patients. Cumulative EULAR Sjögren Syndrome Disease Activity Index results further confirmed these disparities (P = 0.002). Transcriptome analysis linked anti-Ro52/TRIM21 antibody positivity to interferon pathway activation as an underlying cause for these clinical correlations.These results suggest that the combination of anti-Ro52/TRIM21 and anti-Ro60/SSA antibodies is associated with a clinical, biologic, and transcriptional profile linked to greater disease severity in SjD through the potentiation of the interferon pathway activation by anti-Ro52/TRIM21 antibodies

Association of combined anti-Ro52/TRIM21 and anti-Ro60/SSA antibodies with increased Sjögren disease severity through interferon pathway activation

Objective: The biologic diagnosis of primary Sjögren disease (SjD) mainly relies on anti-Ro60/SSA antibodies, whereas the significance of anti-Ro52/TRIM21 antibodies currently remains unclear. The aim of this study was to characterize the clinical, serological, biologic, transcriptomic, and interferon profiles of patients with SjD according to their anti-Ro52/TRIM21 antibody status. Methods: Patients with SjD from the European PRECISESADS (n = 376) and the Brittany Diagnostic Suspicion of primitive Sjögren's Syndrome (DIApSS); (n = 146) cohorts were divided into four groups: double negative (Ro52‾/Ro60‾), isolated anti-Ro52/TRIM21 positive (Ro52+), isolated anti-Ro60/SSA positive (Ro60+), and double-positive (Ro52+/Ro60+) patients. Clinical information; EULAR Sjögren Syndrome Disease Activity Index, a score representing systemic activity; and biologic markers associated with disease severity were evaluated. Transcriptome data obtained from whole blood by RNA sequencing and type I and II interferon signatures were analyzed for PRECISESADS patients. Results: In the DIApSS cohort, Ro52+/Ro60+ patients showed significantly more parotidomegaly (33.3% vs 0%?11%) along with higher β2-microglobulin (P =0.0002), total immunoglobulin (P <0.0001), and erythrocyte sedimentation rate levels (P =0.002) as well as rheumatoid factor (RF) positivity (66.2% vs 20.8%?25%) compared to other groups. The PRECISESADS cohort corroborated these observations, with increased arthritis (P =0.046), inflammation (P =0.005), hypergammaglobulinemia (P <0.0001), positive RF (P <0.0001), leukopenia (P =0.004), and lymphopenia (P =0.009) in Ro52+/Ro60+ patients. Cumulative EULAR Sjögren Syndrome Disease Activity Index results further confirmed these disparities (P =0.002). Transcriptome analysis linked anti-Ro52/TRIM21 antibody positivity to interferon pathway activation as an underlying cause for these clinical correlations. Conclusion: These results suggest that the combination of anti-Ro52/TRIM21 and anti-Ro60/SSA antibodies is associated with a clinical, biologic, and transcriptional profile linked to greater disease severity in SjD through the potentiation of the interferon pathway activation by anti-Ro52/TRIM21 antibodies.Funding: Supported by the Innovative Medicines Initiative Joint Undertaking (grant 115565 [PRECISESADS project]), resources of which include financial contribution from the European Union’s Seventh Framework Program (grant FP7/2007–2013) and EFPIA companies’ in-kind contribution. LBAI laboratory (Lymphocytes B, Auto-immunité et Immunothérapies) was supported by the Agence Nationale de la Recherche under the “Investissement d’Avenir” program (reference ANR-11-LABX-0016-001 [Labex IGO])

Imagerie tridimensionnelle haute résolution du fond sous-marin par le traitement sonar interférométrique à ouverture synthétique

BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF

Estimation statistique des fonctions d'appartenance d'ensembles flous

Nous présentons une méthode nouvelle d'estimation statistique des fonctions d'appartenance d'ensembles flous. Les observations sont les réponses binaires d'experts concernant l'appartenance ou la non appartenance de points (de sondage) à l'ensemble flou considéré. Nous modélisons la loi du processus des observations par un processus de Bernoulli "cohérent" régi par des règles de monotonie des réponses d'experts. Nous étudions les structures statistiques associées à un ou plusieurs experts : identifiabilité, exhaustivité, existence d'estimateur sans biais, etc. Dans le cas des nombres flous, nous proposons des estimateurs ponctuels dont nous étudions la convergence quand le nombre d'experts augmente. Nous donnons ensuite des estimateurs par région de confiance. Les résultats obtenus sont illustrés par des simulations.We introduce a new method for statistical estimation of fuzzy set membership functions. Observations are experts' binary findings on (polling) point membership or non-membership of the fuzzy set under consideration. We model the observation process law as a Bernoulli "coherent" process governed by monotonous rules from the experts' findings. We study the statistical structures of one or more experts : identifiability, exhaustivity, the existence of unbiased estimators and so on. In the case of fuzzy numbers, we propose fix-point estimators. We study their convergence in relation to the increasing number of experts' findings under consideration. We then give confidence area estimators. Some simulations illustrate these results.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF