Segmentation-based video coding system allowing the manipulation of objects

This paper presents a generic video coding algorithm allowing the content-based manipulation of objects. This manipulation is possible thanks to the definition of a spatiotemporal segmentation of the sequences. The coding strategy relies on a joint optimization in the rate-distortion sense of the partition definition and of the coding techniques to be used within each region. This optimization creates the link between the analysis and synthesis parts of the coder. The analysis defines the time evolution of the partition, as well as the elimination or the appearance of regions that are homogeneous either spatially or in motion. The coding of the texture as well as of the partition relies on region-based motion compensation techniques. The algorithm offers a good compromise between the ability to track and manipulate objects and the coding efficiency.Peer ReviewedPostprint (published version

Functional selectivity of adenosine receptor ligands

Adenosine receptors are plasma membrane proteins that transduce an extracellular signal into the interior of the cell. Basically every mammalian cell expresses at least one of the four adenosine receptor subtypes. Recent insight in signal transduction cascades teaches us that the current classification of receptor ligands into agonists, antagonists, and inverse agonists relies very much on the experimental setup that was used. Upon activation of the receptors by the ubiquitous endogenous ligand adenosine they engage classical G protein-mediated pathways, resulting in production of second messengers and activation of kinases. Besides this well-described G protein-mediated signaling pathway, adenosine receptors activate scaffold proteins such as β-arrestins. Using innovative and sensitive experimental tools, it has been possible to detect ligands that preferentially stimulate the β-arrestin pathway over the G protein-mediated signal transduction route, or vice versa. This phenomenon is referred to as functional selectivity or biased signaling and implies that an antagonist for one pathway may be a full agonist for the other signaling route. Functional selectivity makes it necessary to redefine the functional properties of currently used adenosine receptor ligands and opens possibilities for new and more selective ligands. This review focuses on the current knowledge of functionally selective adenosine receptor ligands and on G protein-independent signaling of adenosine receptors through scaffold proteins

Differential impact of L-Arginine deprivation on the activation and effector functions of T cells and macrophages

The metabolism of the amino acid L-arginine is emerging as a crucial mechanism for the regulation of immune responses. Here, we characterized the impact of L-arginine deprivation on T cell and macrophage (MΦ) effector functions: We show that whereas L-arginine is required unconditionally for T cell activation, MΦ can up-regulate activation markers and produce cytokines and chemokines in the absence of L-arginine. Furthermore, we show that L-arginine deprivation does not affect the capacity of activated MΦ to up-regulate L-arginine-metabolizing enzymes such as inducible NO synthase and arginase 1. Thus, our results show that to exert their effector functions, T cells and MΦ have different requirements for L-arginine

Differential impact of l-arginine deprivation on the activation and effector functions of T cells and macrophages

The metabolism of the amino acid l-arginine is emerging as a crucial mechanism for the regulation of immune responses. Here, we characterized the impact of l-arginine deprivation on T cell and macrophage (MΦ) effector functions: We show that whereas l-arginine is required unconditionally for T cell activation, MΦ can up-regulate activation markers and produce cytokines and chemokines in the absence of l-arginine. Furthermore, we show that l-arginine deprivation does not affect the capacity of activated MΦ to up-regulate l-arginine-metabolizing enzymes such as inducible NO synthase and arginase 1. Thus, our results show that to exert their effector functions, T cells and MΦ have different requirements for l-arginine

Segmentation-based video coding system allowing the manipulation of objects

This paper presents a generic video coding algorithm allowing the content-based manipulation of objects. This manipulation is possible thanks to the definition of a spatiotemporal segmentation of the sequences. The coding strategy relies on a joint optimization in the rate-distortion sense of the partition definition and of the coding techniques to be used within each region. This optimization creates the link between the analysis and synthesis parts of the coder. The analysis defines the time evolution of the partition, as well as the elimination or the appearance of regions that are homogeneous either spatially or in motion. The coding of the texture as well as of the partition relies on region-based motion compensation techniques. The algorithm offers a good compromise between the ability to track and manipulate objects and the coding efficiency.Peer Reviewe

Genomic Alterations and Radioresistance in Breast Cancer: An Analysis of the Profiler Protocol

International audiencePurpose/Objective(s)Breast cancer (BC) patients with comparable prognostic features have heterogeneous outcomes, partly because of radiotherapy resistance leading to loco-regional recurrences (LRR). The ProfiLER (Profilage LYric et Région, NCT01774409) clinical trial aims at establishing a simple genetic profile of metastatic cancers in order to offer patients personalized molecular targeted therapies. In the breast cancer area, the genomic profiling of a population who ultimately became metastatic, and its correlation with the patient outcome years after LRR, provided an opportunity to identify post hoc biomarkers of the initial radiation resistance. The aim of the present study was to determine if specific tumor genetic alterations were associated with radiation resistance, defined as a LRR despite optimal surgery, radiotherapy, and systemic adjuvant therapies, in a ProfiLER series.Materials/MethodsGenetic profile of 162 BC patients’ tumors included in ProfiLER between 2013 and 2016 were analyzed using Next-Generation-Sequencing and Comparative-Genomic-Hybridization tests. Patients and tumor characteristics were analyzed for association with genomic rearrangements (mutations, amplification, homozygous deletions). Only gene alterations observed in >3% of the tumors, or included in well-known molecular pathways (PI3 Kinases pathway, MAP Kinases pathway, Tyrosine Kinase receptors family) were selected. The Cox multivariate analysis was based on (P3% of tumors. PIK3CA and ROS1 mutations were statistically correlated to the risk of LRR. A median loco-regional progression free survival (LRPFS) of 19.8 years was reported for PIK3CA mutation carriers (n = 34, 21%) versus 9.1 years for wild-type patients (HR = 0.29, 95% CI = 0.13-0.64, P = 0.002 in univariate analysis). PIK3CA mutation was identified as an independent protective factor of LRR using multivariate analysis (HR = 0.27, 95% CI = 0.09-0.82), P = 0.02). ROS1 mutated cancer patients (n = 8, 4.9%) had a median LRPFS of 4 years versus 16.1 years for wild-type patients (HR = 2.5, 95% CI = 1.74-7.05, P = 0.08 in univariate analysis), but was not identified as an independent LRR risk factor (HR = 2.45 95% CI = 0.83-7.26, P = 0.11 in multivariate analysis). Other mutations and amplifications were not associated with LRR. Among relapsing patients, the median time to LRR was nearly significantly different regarding status of the PIK3CA mutations, with 8.6 years for mutated patients versus4.7 years for non-mutated patients (P = 0.09).ConclusionPIK3CA mutation was associated with a lower risk of LRR in this BC population. ROS1 mutation was marginally associated with a higher risk of LRR, possibly because of a limited population. Results suggest PIK3CA and ROS1to be possible biomarkers of radio-sensitivity

The netrin receptor UNC5B mediates guidance events controlling morphogenesis of the vascular system

Blood vessels and nerves are complex, branched structures that share a high degree of anatomical similarity. Guidance of vessels and nerves has to be exquisitely regulated to ensure proper wiring of both systems. Several regulators of axon guidance have been identified and some of these are also expressed in endothelial cells; however, the extent to which their guidance functions are conserved in the vascular system is still incompletely understood. We show here that the repulsive netrin receptor UNC5B is expressed by endothelial tip cells of the vascular system. Disruption of the Unc5b gene in mice, or of Unc5b or netrin-1a in zebrafish, leads to aberrant extension of endothelial tip cell filopodia, excessive vessel branching and abnormal navigation. Netrin-1 causes endothelial filopodial retraction, but only when UNC5B is present. Thus, UNC5B functions as a repulsive netrin receptor in endothelial cells controlling morphogenesis of the vascular system