929 research outputs found

    Josephson current through a molecular transistor in a dissipative environment

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    We study the Josephson coupling between two superconductors through a single correlated molecular level, including Coulomb interaction on the level and coupling to a bosonic environment. All calculations are done to the lowest, i.e., the fourth, order in the tunneling coupling and we find a suppression of the supercurrent due to the combined effect of the Coulomb interaction and the coupling to environmental degrees of freedom. Both analytic and numerical results are presented.Comment: 11 pages, 6 figures, to appear in Phys. Rev. B; v3: several misprints corrected - in particular, sign inconsistencies throughout the paper should be fixe

    Phase-contrast microtomography: are the tracers necessary for stem cell tracking in infarcted hearts?

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    Recent literature has identified innovative approaches of cellular therapy to generate new myocardium involving transcoronary and intramyocardial injection of cardiac progenitor cells (CPCs). One of the limiting factors in the overall interpretation of these preclinical results is the lack of reliable methods for 3D imaging and quantification of the injected cells and for the assessment of their fate within the myocardium. Here, for the first time to the authors' knowledge, we support by demonstrative experiments the hypothesis that phase-contrast microtomography (PhC-microCT) could offer an efficient 3D imaging approach to track the injected cells within the myocardium, without the need of any cell tracer. This deduction has been validated by several observations: i) a strong phase-contrast signal was observed in infarcted hearts injected with unlabeled cells; ii) the PhC-microCT 3D reconstructions of hearts injected with only vehicle saline solution and rhodamine particles, i.e. without CPCs, did not show any contrast; (iii) in the 3D PhC-microCT reconstructions of non infarcted hearts, injected with unlabeled CPCs, the contrast signal of the cells was present but differently distributed; and iv) the contrast signal of injected cells diminished over time apparently following the same timing of cell engraftment and differentiation, as confirmed in literature by histology and fluorescence analysis. The chance to avoid cell tracers is of paramount interest in determining the fate of transplanted stem cells because the quantification of the signal will not be any more dependent on injected dose, concentration of the tracer, cell proliferation and tracer uptake kinetics

    Stress proteins in experimental nephrotoxicity: a ten year experience

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    Heat shock proteins and glucose­regulated proteins represent an extraordinary mechanism of defense induced in the kidney by chemicals or drugs and essential to survive. Here we resume our experience on the presence and regulation of stress proteins into acute and chronic nephrotoxic models in rodents and in vitro. In acute renal damage, induced in rats by a single injection of inorganic mercury, stress proteins enhanced in a dose-dependent manner to recover cytoskeleton and mitochondria and maintain nuclear activity. When we pre-treated mercury injected-rats with antioxidant melatonin or with bimoclomol, a stress proteins-coinducer, stress proteins expression was modulated together with tubular recovery. Similar data were obtained in ischemia-reperfusion in rats treated with stannous chloride, that provided cytoprotection stimulating heme oxygenase induction. During nephrotoxicity induced by administration of cyclosporine A at therapeutic dosage for 1-2 months, stress protein overexpression well correlated with oxidative and cell death, but decreased if we counteracted renal damage using antioxidants. In aluminium intoxication through drinking water for 3-6 months, we detected a time-dependent stress response in the rat kidney that was organ specific and different from the liver. In vitro studies on rat tubular proximal cells exposed to heavy metals demonstrated that stress protein expression was related to peculiar mechanisms of action of each metal. In conclusion, experimental studies on the renal chaperones can greatly contribute to understand their role, and agents able to modulate the stress response might be considered promising therapeutic tools to reduce nephrotoxicity

    Recombinant adeno associated viral (AAV) vector type 9 delivery of Ex1-Q138-mutant huntingtin in the rat striatum as a short-time model for in vivo studies in drug discovery

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    Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by dyskinesia, cognitive impairment and emotional disturbances, presenting progressive neurodegeneration in the striatum and intracellular mutant Huntingtin (mHTT) aggregates in various areas of the brain. Recombinant Adeno Associated Viral (rAAV) vectors have been successfully used to transfer foreign genes to the brain of adult animals. In the present study we report a novel in vivo rat HD model obtained by stereotaxic injection of rAAV serotype2/9 containing Exon1-Q138 mHTT (Q138) and Exon1-Q17 wild type HTT (Q17; control), respectively in the right and in the left striatum, and expressed as C-terminal GFP fusions to facilitate detection of infected cells and aggregate production. Immunohistochemical analysis of brain slices from animals sacrificed twenty-one days after viral infection showed that Q138 injection resulted in robust formation of GFP-positive aggregates in the striatum, increased GFAP and microglial activation and neurodegeneration, with little evidence of any of these events in contralateral tissue infected with wild type (Q17) expressing construct. Differences in the relative metabolite concentrations (N-Acetyl Aspartate/Creatine and Myo-Inositol/Creatine) were observed by H1 MR Spectroscopy. By quantitative RT-PCR we also demonstrated that mHTT induced changes in the expression of genes previously shown to be altered in other rodent HD models. Importantly, administration of reference compounds previously shown to ameliorate the aggregation and neurodegeneration phenotypes in preclinical HD models was demonstrated to revert the mutant HTT-dependent effects in our model. In conclusion, the AAV2/9-Q138/Q17 exon 1 HTT stereotaxic injection represents a useful first-line in vivo preclinical model for studying the biology of mutant HTT exon 1 in the striatum and to provide early evidence of efficacy of therapeutic approaches

    Metabolic Signature of Arrhythmogenic Cardiomyopathy

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    Arrhythmogenic cardiomyopathy (ACM) is a genetic-based cardiac disease accompanied by severe ventricular arrhythmias and a progressive substitution of the myocardium with fibro-fatty tissue. ACM is often associated with sudden cardiac death. Due to the reduced penetrance and variable expressivity, the presence of a genetic defect is not conclusive, thus complicating the diagnosis of ACM. Recent studies on human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) obtained from ACM individuals showed a dysregulated metabolic status, leading to the hypothesis that ACM pathology is characterized by an impairment in the energy metabolism. However, despite efforts having been made for the identification of ACM specific biomarkers, there is still a substantial lack of information regarding the whole metabolomic profile of ACM patients. The aim of the present study was to investigate the metabolic profiles of ACM patients compared to healthy controls (CTRLs). The targeted Biocrates AbsoluteIDQ® p180 assay was used on plasma samples. Our analysis showed that ACM patients have a different metabolome compared to CTRLs, and that the pathways mainly affected include tryptophan metabolism, arginine and proline metabolism and beta oxidation of fatty acids. Altogether, our data indicated that the plasma metabolomes of arrhythmogenic cardiomyopathy patients show signs of endothelium damage and impaired nitric oxide (NO), fat, and energy metabolism

    Vascular oxidative stress-induced senescence is minimized by melatonin intake in ApoE-deficient mice 

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    Aging is a natural process that produces deleterious changes in all tissues of the organism. One leading theory about the cause of aging suggest that oxidative stress play a fundamental role in pathogenesis. Oxidative stress induces intracellular damage that affects all biological components, including, DNA, lipids, sugars and proteins. Therefore, the imbalance between intracellular reactive oxygen species (ROS) and antioxidant defence mechanisms results in harmful oxidative stress. One of the most widely considered strategies for preventing aging and for treating age-related disease is the use of natural anti-oxidant agents, such as melatonin and resveratrol. Melatonin is a potent endogenous anti-oxidant neurohormone, which acts through various mechanisms to ameliorate the toxic effects of ROS. However, little is known about the mechanisms of signalling pathways through which melatonin acts to reverse the effects of ROS. In the present study we treated ApoE-deficient mice, a well-known senescence model, from 6th week to 15th week of life, with a specific melatonin formulation: Armonia Retard (kindly provided by Nathura s.r.l, Reggio Emilia, Italy), with an extended-release pharmacokinetic, at different progressive doses 0.04, 0.1, 10 mg/kg/day. We used the same treatment in C57BL6 mice, as control group. Vascular alterations were evaluated in aorta by morphology and immunofluorescence analysis was focused on pleiotropic inflammatory markers, such as interleukins (IL) 6 and 10, inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α). We observed in ApoE-deficient mice endothelial cell detachment and  IL-6, IL-10, iNOS and TNF-α overexpression. Melatonin treatment improved not only the endothelial damage, but also the overall vascular cytoarchitecture and reduced inflammation and macrophages infiltration. In particular, melatonin Retard at the highest dose, recovered all the above markers to the levels of C57BL6 mice. These results outline the anti-inflammatory and anti-oxidant properties of melatonin and its beneficial anti-aging and anti-atherosclerotic effects, especially in extended-release formulation

    Generation and characterization of three human induced pluripotent stem cell lines (EURACi007-A, EURACi008-A, EURACi009-A) from three different individuals of the same family with arrhythmogenic cardiomyopathy (ACM) carrying the plakophillin2 p.N346Lfs*12 mutation.

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    Abstract Arrhythmogenic Cardiomyopathy (ACM) is a genetically based cardiomyopathy associated with ventricular arrhythmias and fibro-fatty substitution of cardiac tissue. It is characterized by incomplete penetrance. We generated human iPSCs by episomal reprogramming of blood cells from three members of the same family: the proband, affected by ACM and carrying the heterozygous plakophillin2 p.N346Lfs*12 mutation, one asymptomatic carrier of the same mutation and one apparently healthy control. hiPSCs were characterized according to standard protocols including karyotyping, pluripotency marker expression and differentiation towards the three germ layers. These hiPSC lines can be used to study the mechanisms of ACM incomplete penetrance in vitro

    Genome-enabled predictions for fruit weight and quality from repeated records in European peach progenies

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    Background: Highly polygenic traits such as fruit weight, sugar content and acidity strongly influence the agroeconomic value of peach varieties. Genomic Selection (GS) can accelerate peach yield and quality gain if predictions show higher levels of accuracy compared to phenotypic selection. The available IPSC 9K SNP array V1 allows standardized and highly reliable genotyping, preparing the ground for GS in peach. Results: A repeatability model (multiple records per individual plant) for genome-enabled predictions in eleven European peach populations is presented. The analysis included 1147 individuals derived from both commercial and non-commercial peach or peach-related accessions. Considered traits were average fruit weight (FW), sugar content (SC) and titratable acidity (TA). Plants were genotyped with the 9K IPSC array, grown in three countries (France, Italy, Spain) and phenotyped for 3–5 years. An analysis of imputation accuracy of missing genotypic data was conducted using the software Beagle, showing that two of the eleven populations were highly sensitive to increasing levels of missing data. The regression model produced, for each trait and each population, estimates of heritability (FW:0.35, SC:0.48, TA:0.53, on average) and repeatability (FW:0.56, SC:0.63, TA:0.62, on average). Predictive ability was estimated in a five-fold cross validation scheme within population as the correlation of true and predicted henotypes. Results differed by populations and traits, but predictive abilities were in general high (FW:0.60, SC:0.72, TA:0.65, on average). Conclusions: This study assessed the feasibility of Genomic Selection in peach for highly polygenic traits linked to yield and fruit quality. The accuracy of imputing missing genotypes was as high as 96%, and the genomic predictive ability was on average 0.65, but could be as high as 0.84 for fruit weight or 0.83 for titratable acidity. The estimated repeatability may prove very useful in the management of the typical long cycles involved in peach productions. All together, these results are very promising for the application of genomic selection to peach breeding programmes.info:eu-repo/semantics/publishedVersio

    The Role of Anti-Angiogenics in Pre-Treated Metastatic BRAF-Mutant Colorectal Cancer: A Pooled Analysis

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    : Background. FOLFOXIRI plus Bevacizumab is one of the most frequently used first-line treatments for patients with BRAF-mutant colorectal cancer (CRC), while second-line treatment requires extensive further research. In this pooled analysis, we evaluate the impact of anti-angiogenics in patients with pre-treated BRAF-mutant CRC. Methods. We monitored patients in randomized, controlled studies who had advanced CRC and were undergoing second-line chemotherapy in addition to utilizing Bevacizumab, Ramucirumab or Aflibercept treatments. These data were pooled together with the data and results of BRAF-mutant patients enrolled in two phase III trials (TRIBE and TRIBE-2 study), who had been treated with second-line treatment both with or without Bevacizumab. Overall survival (OS), in relation to BRAF mutational status, was the primary focus. Results. Pooled analysis included 129 patients. Anti-angiogenics were found to have a significant advantage over the placebo in terms of OS (HR 0.50, 95%CI 0.29-0.85) (p = 0.01). Conclusions. Our pooled analysis confirms the efficacy of anti-angiogenics in pre-treated BRAF-mutant CRC, establishing the combination of chemotherapy plus Bevacizumab or Ramucirumab or Aflibercept as a valid treatment option

    Functional and usability assessment of a robotic exoskeleton arm to support activities of daily life

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    An assistive device for upper limb support was developed and evaluated in terms of usability, user satisfaction and motor performance on six end-users affected by neuro-motor disorders (three spinal cord injury; one multiple sclerosis; two Friedreich's ataxia). The system consisted of a lightweight 3-degrees-of-freedom robotic exoskeleton arm for weight relief, equipped with electromagnetic brakes. Users could autonomously control the brakes using a USB-button or residual electromyogram activations. The system functionally supported all of the potential users in performing reaching and drinking tasks. For three of them, time, smoothness, straightness and repeatability were also comparable to healthy subjects. An overall high level of usability (system usability score, median value of 90/100) and user satisfaction (Tele-healthcare Satisfaction Questionnaire - Wearable Technology, median value of 104/120) were obtained for all subject
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