Angiogenic Activity in the Sera of Patients with Post-Kidney Transplant Erythrocytosis

International audiencePost-kidney transplant erythrocytosis (PTE) is one of the hematological complications in the renal transplant patients. While its pathogenesis still remains to be elucidated completely, a number of therapies are available for the management of PTE. The aim of this prospective study was to investigate whether angiogenesis may be involved in the pathogenesis of post-transplant erythrocytosis by comparing its level with those of different classes of erythrocytosis [polycythemia vera (PV), idiopathic erythrocytosis and secondary erythrocytosis]. The angiogenic activity was evaluated by the assessment of the serum vascular endothelial growth factor (VEGF) levels, as one of circulating angiogenic factor, using a standardized enzyme-linked immunosorbent assay commercial kit in 13 PTE (2 F/11 M), in 75 untreated erythrocytosis non-transplant patients and in 21 healthy subjects controls. The results indicated that VEGF was overproduced in advanced and untreated PV patients and to a lesser degree in idiopathic erythrocytosis thus confirming an increased angiogenic activity. However, there is no evidence of increased angiogenesis in PTE and in secondary erythrocytosis. The absence of angiogenesis in PTE and its presence in PV is another argument that the pathogenesis of these two entities is different

Hybrid PET/MRI co-segmentation based on joint fuzzy connectedness and graph cut

International audienceBACKGROUND AND OBJECTIVE:Tumor segmentation from hybrid PET/MRI scans may be highly beneficial in radiotherapy treatment planning. Indeed, it gives for both modalities the suitable information that could make the delineation of tumors more accurate than using each one apart. We aim in this work to propose a co-segmentation method that deals with several challenges, notably the lack of one-to-one correspondence between tumors of the two modalities and the boundaries' smoothing.METHODS:The proposed method is designed to surpass these limits, we propose a segmentation method based on the GCsummax technique. The method takes the advantage of Iterative Relative Fuzzy Connectedness (IRFC) on seeds initialization, and the standard min-cut/max-flow technique for the boundary smoothing. Seed initialization was accurately performed thanks to high uptake regions on PET. Besides, a visibility weighting scheme was adapted to achieve the task of co-segmentation using the IRFC algorithm. Then, given the co-segmented regions, we introduce a morphological-based technique that provides object seeds to standard Graph Cut (GC) allowing it to avoid the shrinking problem. Finally, for each modality, the segmentation task is formulated as an energy minimization problem which is resolved by a min-cut/max-flow technique.RESULTS:The overlap ratio (denoted DSC) between our segmentation results and the ground-truth for PET images is 92.63  ±  1.03, while the DSC for MRI images is 90.61  ±  3.70.CONCLUSIONS:The proposed method was tested on different types of diseases and it outperformed the state-of-the-art methods. We show its superiority in terms of assymetric relation between PET and MRI and tumors heterogeneity

Genetic heterogeneity of megaloblastic anaemia type 1 in Tunisian patients

International audienceMegaloblastic anaemia 1 (MGA1) is a rare autosomal recessive condition characterized by selective intestinal vitamin B12 malabsorption and proteinuria. More than 200 MGA1 patients have been identified worldwide, but the disease is relatively prevalent in Finland, Norway and several Eastern Mediterranean regions. MGA1 is genetically heterogeneous and can be caused by mutations in either the cubilin (CUBN) or the amnionless (AMN) gene. In the present study we investigated the molecular defect underlying MGA1 in nine Tunisian patients belonging to six unrelated consanguineous families. Haplotype and linkage analyses, using microsatellite markers surrounding both CUBN and AMN genes, indicated that four out of the six families were likely to be linked to the CUBN gene. Patients from these families were screened for the Finnish, Mediterranean and Arabian mutations already published. None of the screened mutations could be detected in our population. One family showed a linkage to AMN gene. Direct screening of the AMN gene allowed the identification of the c.208-2A > G mutation, previously described in a Jewish Israeli patient of Tunisian origin and in Turkish patients. This suggests that the c.208-2A > G mutation may derive from a single Mediterranean founder ancestor. For the last family, haplotype analysis excluded both CUBN and AMN genes, suggesting the existence of a third locus that may cause MGA1