Generalized mixture estimation in hidden Markov trees, application to segmentation of images of street organ cards

We deal in this paper with unsupervised statistical image segmentation using hidden Markov trees. First, we propose two original evolutionary models and study, via simulations, the behaviour of different general estimation methods. Second, we propose a new generalized mixture estimation method and show its efficiency in unsupervised image segmentation, even in very noisy settings. The proposed method is then successfully applied to the unsupervised segmentation of street organ cards images.Nous nous intéressons dans cet article à la segmentation statistique non supervisée d'images avec les modèles par arbres de Markov cachés. Dans un premier temps nous proposons deux modèles évolutifs originaux et étudions, via simulations, le comportement des diverses méthodes générales de l'estimation des paramètres. Ensuite, nous proposons une méthode originale d'estimation de mélanges généralisés et montrons son bon comportement, même dans des cas d'images très fortement bruiteés, par une étude de simulations. Cette même méthode est appliquée au problème de la segmentation des cartons d'orgue de barbarie, attestant de son intérêt dans une situation réelle

Segmentation non supervisée des images par arbres de Markov couple

Nous traitons dans cet article de la segmentation statistique non supervisée d'images de synthèse en utilisant le modèle récent des arbres de Markov couple. L'objectif de cet article est de montrer que la stricte généralisation du modèle des arbres de Markov cachés apporte, notamment dans le cas non supervisé où un algorithme original de type ICE est proposé, un gain appréciable au niveau de la qualité de la segmentation. Les exemples traités montrent en effet que le modèle des diarbres de Markov couple permet d'améliorer les résultats obtenus pour les diarbres de Markov cachés

Microscopic Polyangiitis With Selective Involvement of Central and Peripheral Nervous System : A Case Report

Background: Microscopic polyangiitis (MPA) is a necrotizing vasculitis that affects predominantly small-sized vessels in many organ systems. The disease generally causes glomerulonephritis, pulmonary damage, arthritis, and neuropathy. An exclusive involvement of both central nervous system (CNS) and peripheral nervous system (PNS) is extremely rare. Case Presentation: A 62-year-old woman was admitted to our hospital with a 3 months history of right foot drop, recently complicated by intense myalgia, arthralgia, and allodynia to tactile, vibratory, and pressure stimuli. Since blood tests revealed elevated inflammatory indexes, we suspected either infectious or immune-mediated disorders. Chest radiograph, blood culture series, and echocardiogram revealed normal findings, while urinalysis showed a bacterial infection that was successfully treated. The neurophysiological findings were compatible with multiple mononeuritis, and a brain MRI evidenced ischemic lesions of both basal ganglia and thalamus. A wide-spectrum autoantibody assay revealed the presence of high-titer perinuclear anti-neutrophil cytoplasmic antibodies specific for myeloperoxidase (MPO-ANCA). According to these findings, the diagnosis of MPA was made, and the patient was successfully treated with intravenous (IV) methylprednisolone, followed by two doses of rituximab. Conclusions: An assessment of both CNS and PNS should be included in the diagnostic evaluation of MPA. The involvement of the PNS may raise the risk of a relapsing course and treatment failure, therefore it should be considered in the choice of induction and maintenance therapy

Case report: Asp194Ala variant in MFN2 is associated with ALS-FTD in an Italian family

Background:MFN2 gene encodes the protein Mitofusin 2, involved in essential mitochondrial functions such as fusion, trafficking, turnover, and cellular interactions. We describe a family carrying a novel MFN2 mutation associated with ALS-frontotemporal dementia (FTD) clinical phenotype in the mother and Charcot-Marie-Tooth disease type 2A (CMT2A) in her son.Case presentation: The mother, a 67-year-old woman, referred to us for a three year-history of mood disturbance and gait impairment, and a more recent hypophonia, dysarthria, dysphagia, and diffuse muscle wasting. Family history was positive for psychiatric disorders and gait disturbances. Brain 18F-FDG PET showed severe hypometabolism in the fronto-temporal brain cortex bilaterally. Electrodiagnostic studies (EDX) showed severe motor axonopathy in the bulbar, cervical and lumbosacral districts. Her 41-year-old son had a history of mood depression and sensory disturbances in the limbs, along with mild muscle wasting, weakness, and reduced reflexes. Nerve conduction studies revealed a moderate sensory-motor polyneuropathy, while brain MRI was normal. Whole exome sequencing of the patients’ DNA identified the novel MFN2 (NM_014874.4) variant c.581A>C p.(Asp194Ala).Conclusion: Our findings provide evidence of heterogenous clinical manifestations in family members sharing the same MFN2 molecular defect. Additionally, we present the first documented case of ASL-FTD associated with an MFN2 mutation, thereby expanding the range of MFN-related disorders. Further research involving larger cohorts of patients will be needed to better understand the role of MFN2 as a contributing gene in the development of ALS-FTD

Clinical reasoning: a 75-year-old man with parkinsonism, mood depression, and weight loss

A 75-year-old man presented to the emergency department with a 1-year history of 66-pound weight loss and alternating bowel habits. He was admitted to the hospital, where he underwent several examinations to investigate the presence of a malignancy. A colonoscopy, a gastroscopy, an ultrasound of the abdomen, and a contrast-enhanced CT scan of thorax and abdomen did not detect any neoplasia. The only findings consisted of a prostatic hypertrophy and a basal pleural-parenchymal hyperdensity in the left lung, which was described as the result of an infective process. Neoplastic markers CA19.9, carcinoembryonic antigen, neuron-specific enolase, and \u3b1-fetoprotein were also negative. Wide-spectrum blood tests were unremarkable, except for hypogammaglobulinemia and elevated \u3b22 microglobulin

Therapeutic potential of Mesenchymal Stem Cells for the treatment of type-1 Diabetes

The transplantation of pancreatic islets is an innovative and intriguing therapeutic option for the long term treatment of type-1 diabetes (Remuzzi et al., 2009). Unfortunately, their clinical feasibility is limited by the great number of islets necessary to achieve glycaemic control and their short survival. A possible means to improve the performance of this technique can be represented by Mesenchymal Stem Cells (MSCs), adult stem cells alrady known to support the survival of different cellular populations (Scuteri et al., 2014). In this work the ability of Mesenchymal Stem Cells (MSCs) to improve the feasibility of this approach was verified into an in vivo model represented by Streptozotocin-induced diabetic rats. We compared 5 different groups (8 rats/group): a) healthy controls; b) Diabetic rats; c) Diabetic rats transplanted with pancreatic islets (3000); d) Diabetic rats cotransplanted with pancreatic islets (2000) and MSCs (106); Diabetic rats treated with MSCs (106). Transplantations were performed after the assessment of neuropathic signs, represented by a decreased Nerve Conduction Velocity (NCV) and an impairment of nociceptive thermal and mechanical thresholds. The same parameters were evaluated two months after the transplantation. Diabetic rats transplanted only with pancreatic islets, or co-transplanted with MSCs and a suboptimal number of pancreatic islets, showed a significant glycaemia value reduction, an improvement of thermal and mechanical sensitivity, and an improvement of NCV with respect to diabetic-untreated rats. No differences were observed between diabetic rats and diabetic rats treated with only MSCs. In conclusion, we demonstrated that co-transplantation with MSCs reduces the number of pancreatic islets needed to reach glycaemic control, and induces the regression of painful neuropathy signs, thus ameliorating diabetes complications management. Granted by MIUR – FIRB Futuro in Ricerca 2008 Prot. N° RBFR08VSVI_001

Dystonia-ataxia syndrome with permanent torsional nystagmus caused by ECHS1 deficiency

Biallelic mutations in ECHS1, encoding the mitochondrial enoyl-CoA hydratase, have been associated with mitochondrial encephalopathies with basal ganglia involvement. Here, we describe a novel clinical presentation consisting of dystonia-ataxia syndrome with hearing loss and a peculiar torsional nystagmus observed in two adult siblings. The presence of a 0.9-ppm peak at MR spectroscopy analysis suggested the accumulation of branched-chain amino acids. Exome sequencing in index probands identified two ECHS1 mutations, one of which was novel (p.V82L). ECHS1 protein levels and residual activities were reduced in patients' fibroblasts. This paper expands the phenotypic spectrum observed in patients with impaired valine catabolism