Brain Tumor Vascular Network Segmentation from Micro-Tomography

Micro-tomography produces high resolution images of bio- logical structures such as vascular networks. In this paper, we present a new approach for segmenting vascular network into pathological and normal regions from considering their micro-vessel 3D structure only. We define and use a condi- tional random field for segmenting the output of a watershed algorithm. The tumoral and normal classes are thus character- ized by their respective distribution of watershed region size interpreted as local vascular territories

Vascular network segmentation: an unsupervised approach

Micro-tomography produces high resolution images of biological structures such as vascular networks. In this paper, we present a new approach for segmenting vascular network into pathological and normal regions from considering their micro-vessel 3D structure only. We consider a partition of the volume obtained by a watershed algorithm based on the distance from the nearest vessel. Each territory is characterized by its volume and the local vascular density. The volume and density maps are first regularized by minimizing the total variation. Then, a new approach is proposed to segment the volume from the two previous restored images based on hypothesis testing. Results are presented on 3D micro-tomographic images of the brain micro-vascular network

Les pays de l'Union européenne face aux nouvelles dynamiques des migrations internationales: Ampleur des migrations et caractéristiques des migrants

National audienceThis article is based on an innovative study of migration in Europe exploiting complementary data bases and developing a new typology of migrant categories. The study makes it possible to determine foreign population trends in the EU member states according to several criteria (nationality of migrants, country of birth, employment contracts, sector of employment, level of qualification, etc.) and the dynamic of migration flows from within and outside the EU. The new phenomenon of reiterated migration within the European area is also highlighted. A strong dissymmetry of EU countries' relative positions with respect to migration emerges: some are traditional receiving countries and implement selective opening policies while new immigration countries in Southern Europe operate as transit countries for young and highly qualified migrants from Central and Eastern Europe and the developing countries. There is thus a renewal of migration within the European space, as well as greater complexity, given the growth in reiterated migration of third-country nationals.Cet article s'appuie sur une étude originale des migrations en Europe fondée sur l'exploitation de bases de données complémentaires et l'élaboration d'une typologie nouvelle des catégories de migrants. Il permet de connaître l'évolution de la population étrangère dans les pays membres de l'Union selon plusieurs critères (nationalité des migrants, pays de naissance, contrats de travail, secteur d'activité, niveau de qualification...) et la dynamique des flux migratoires intra et extracommunautaires. Le phénomène nouveau des migrations répétées dans l'espace européen est également mis en évidence. Il apparaît une forte asymétrie des positions relatives des pays européens en termes d'immigration : certains sont des pays d'accueil traditionnels et mènent des politiques d'ouverture sélective tandis que les nouveaux pays d'immigration d'Europe du Sud servent de pays relais pour des migrants diplômés et jeunes en provenance des pays d'Europe centrale et orientale et des pays en développement. Les migrations dans l'espace européen connaissent ainsi une relance et une complexification avec une montée des circulations migratoires répétées d'origine extracommunautaire

Les pays de l'Union européenne face aux nouvelles dynamiques des migrations internationales

Cet article s'appuie sur une étude originale des migrations en Europe fondée sur l'exploitation de bases de données complémentaires et l'élaboration d'une typologie nouvelle des catégories de migrants. Il permet de connaître l'évolution de la population étrangère dans les pays membres de l'Union selon plusieurs critères (nationalité des migrants, pays de naissance, contrats de travail, secteur d'activité, niveau de qualification...) et la dynamique des flux migratoires intra et extracommunautaires. Le phénomène nouveau des migrations répétées dans l'espace européen est également mis en évidence. Il apparaît une forte asymétrie des positions relatives des pays européens en termes d'immigration : certains sont des pays d'accueil traditionnels et mènent des politiques d'ouverture sélective tandis que les nouveaux pays d'immigration d'Europe du Sud servent de pays relais pour des migrants diplômés et jeunes en provenance des pays d'Europe centrale et orientale et des pays en développement. Les migrations dans l'espace européen connaissent ainsi une relance et une complexification avec une montée des circulations migratoires répétées d'origine extracommunautaire.flux migratoires; migrations répétées; Europe; politiques d'immigration; mobilité européenne

Les pays de l’Union Européenne face aux nouvelles dynamiques des migrations internationales. Ampleur des migrations et caractéristiques des migrants.

Marchés du travail; Mobilité; Flux migratoires; Migrations dans l'Union Européenne;

Cause-specific telomere factors deregulation in hepatocellular carcinoma.

International audienceBACKGROUND: Among the numerous genetic defects associated with hepatocarcinogenesis, telomere abnormalities appear to play a role both in tumor promotion and maintenance. Telomeres, the chromosome extremities, are protected by specific proteins, the shelterin complex and by additional factors. Besides telomerase dysregulation, expression changes of these telomere factors have been observed in cancers. METHODS: Here, we tested the hypothesis that such dysregulation might occur in hepatocellular carcinoma (HCC) with specific patterns depending on the cause of HCC. We compared telomere length, telomerase activity (TA), hTERT and telomere genes expression using PCR and Western-blot analyses between non-cirrhotic liver, peritumoral cirrhotic tissue (40 samples) and cancerous tissue (40 samples) derived from 40 patients with HBV-, HCV-, or alcohol-related HCC. RESULTS: Alterations in TA, hTERT expression and telomere length between non-cirrhotic, cirrhotic, and tumor samples were not significantly influenced by the cause of HCC. In contrast, the expression pattern of hTR, shelterin, and non-shelterin telomere protective factors clearly distinguished the 3 causes of cirrhosis and HCC. For patients with HBV diseased liver, when compared with non-cirrhotic liver, the cirrhotic tissue underexpressed all shelterin and all but HMRE11A and RAD50 non-shelterin telomere factors. For HCV the expression level of POT1, RAP1, Ku80, and RAD50 was higher in cirrhotic than in non-cirrhotic liver samples without evidence for significant transcriptional change for the remaining genes. For alcohol-related liver diseases, the expression level of POT1, RAP1, TIN2, hMRE11A, hMRE11B, Ku70, Ku80, RAD50, TANK1, and PINX1 was higher in cirrhotic than in non-cirrhotic liver samples. For the 3 causes of HCC, there was no significant change in shelterin and non-shelterin gene expression between cirrhosis and HCC samples. CONCLUSIONS: These results validate our hypotheses and demonstrate that cirrhosis and HCC add-up numerous telomere dysfunctions including numerous cause-specific changes that appear to occur early during the course of the disease

Characterization of anomalous Zeeman patterns in complex atomic spectra

The modeling of complex atomic spectra is a difficult task, due to the huge number of levels and lines involved. In the presence of a magnetic field, the computation becomes even more difficult. The anomalous Zeeman pattern is a superposition of many absorption or emission profiles with different Zeeman relative strengths, shifts, widths, asymmetries and sharpnesses. We propose a statistical approach to study the effect of a magnetic field on the broadening of spectral lines and transition arrays in atomic spectra. In this model, the sigma and pi profiles are described using the moments of the Zeeman components, which depend on quantum numbers and Land\'{e} factors. A graphical calculation of these moments, together with a statistical modeling of Zeeman profiles as expansions in terms of Hermite polynomials are presented. It is shown that the procedure is more efficient, in terms of convergence and validity range, than the Taylor-series expansion in powers of the magnetic field which was suggested in the past. Finally, a simple approximate method to estimate the contribution of a magnetic field to the width of transition arrays is proposed. It relies on our recently published recursive technique for the numbering of LS-terms of an arbitrary configuration.Comment: submitted to Physical Review

Implication of the Autologous Immune System in BCR-ABL Transcript Variations in Chronic Myelogenous Leukemia Patients Treated with Imatinib.

International audienceImatinib and other tyrosine kinase inhibitors (TKI) have improved treatment of chronic myelogenous leukemia (CML); however, most patients are not cured. Deeper mechanistic understanding may improve TKI combination therapies to better control the residual leukemic cell population. In analyzing our patients' data, we found that many patients who otherwise responded well to imatinib therapy still showed variations in their BCR-ABL transcripts. To investigate this phenomenon, we applied a mathematical model that integrates CML and an autologous immune response to the patients' data. We define an immune window or a range of leukemic loads for which the autologous immune system induces an improved response. Our modeling results suggest that, at diagnosis, a patient's leukemic load is able to partially or fully suppress the autologous immune response developed in a majority of patients, toward the CML clone(s). Imatinib therapy drives the leukemic population into the "immune window," allowing the patient's autologous immune cells to expand and eventually mount an efficient recognition of the residual leukemic burden. This response drives the leukemic load below this immune window, allowing the leukemic population to partially recover until another weaker immune response is initiated. Thus, the autologous immune response may explain the oscillations in BCR-ABL transcripts regularly observed in patients on imatinib