225 research outputs found

    Coherence and anticoherence resonance tunned by noise

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    We present numerical evidence and a theoretical analysis of the appearance of anticoherence resonance induced by noise, not predicted in former analysis of coherence resonance. We have found that this phenomenon occurs for very small values of the intensity of the noise acting on an excitable system, and we claim that this is a universal signature of a nonmonotonous relaxational behavior near its oscillatory regime. Moreover, we demonstrate that this new phenomenon is totally compatible with the standard situation of coherence resonance appearing at intermediate values of noise intensity

    Evaporation and coarsening dynamics with open boundaries

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    We present a study of the evaporation dynamics of a substance undergoing a coarsening process. The system is modeled by the Cahn-Hilliard equation with absorbing boundaries. We have found that the dynamics, although of a diffusive nature, is much slower than the usual one without coarsening. Analytical and simulation results are in reasonable agreement

    Competitive evaporation in arrays of droplets

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    We consider the evaporation of periodic arrays of initially equal droplets in two-dimensional systems with open (absorbing) boundaries. Our study is based on the numerical solution of the Cahn-Hilliard equation. We show that due to cooperative effects the droplets which are further from the boundary may evaporate earlier than those in the boundary¿s vicinity. The time evolution of the overall amount of matter in the system is also studied

    Electrophysiological effects of extracellular vesicles secreted by cardiosphere-derived cells: Unraveling the antiarrhythmic properties of cell therapies

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    This article belongs to the Special Issue Advances in Regenerative Medicine and Tissue Engineering.Although cell-based therapies show potential antiarrhythmic effects that could be mediated by their paracrine action, the mechanisms and the extent of these effects were not deeply explored. We investigated the antiarrhythmic mechanisms of extracellular vesicles secreted by cardiosphere-derived cell extracellular vesicles (CDC-EVs) on the electrophysiological properties and gene expression profile of HL1 cardiomyocytes. HL-1 cultures were primed with CDC-EVs or serum-free medium alone for 48 h, followed by optical mapping and gene expression analysis. In optical mapping recordings, CDC-EVs reduced the activation complexity of the cardiomyocytes by 40%, increased rotor meandering, and reduced rotor curvature, as well as induced an 80% increase in conduction velocity. HL-1 cells primed with CDC-EVs presented higher expression of SCN5A, CACNA1C, and GJA1, coding for proteins involved in INa, ICaL, and Cx43, respectively. Our results suggest that CDC-EVs reduce activation complexity by increasing conduction velocity and modifying rotor dynamics, which could be driven by an increase in expression of SCN5A and CACNA1C genes, respectively. Our results provide new insights into the antiarrhythmic mechanisms of cell therapies, which should be further validated using other models.This research was funded by the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Spain: PI16/01123, PI17/01059, Red de Terapia Celular-Tercel-RD16.0011.0029 and CIBERCV-CB16.11.00292

    Insights into Growth Factors in Liver Carcinogenesis and Regeneration: An Ongoing Debate on Minimizing Cancer Recurrence after Liver Resection

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    This research was funded by the Ministerio de Ciencia, Innovacion y Universidades (Project Grant RTI2018-095114-B-I00) Madrid, Spain; European Union (Fondos FEDER, "una manera de hacer Europa"); CERCA Program/Generalitat de Catalunya; the Secretaria d' Universitats I Recerca del Departament d' Economia I Coneixement (Project Grant 2017_SGR_551) Barcelona, Spain, by the COST action Programs CA17103 (DARTER), CA17112 (PRO-EURO-DILI-NET), CA17121 (COMULIS) and CA17126 (TUMIEE), and by the Consejo Nacional de Ciencia y Tecnologia (CONACYT), Fondo Sectorial de Investigacion para la Educacion (Project grant 257743), Mexico. Marc Mico-Carnero is the recipient of a fellowship from FCT (Fundacio Catalana de Trasplantament), Spain.Hepatocellular carcinoma has become a leading cause of cancer-associated mortality throughout the world, and is of great concern. Currently used chemotherapeutic drugs in the treatment of hepatocellular carcinoma lead to severe side effects, thus underscoring the need for further research to develop novel and safer therapies. Liver resection in cancer patients is routinely performed. After partial resection, liver regeneration is a perfectly calibrated response apparently sensed by the body’s required liver function. This process hinges on the effect of several growth factors, among other molecules. However, dysregulation of growth factor signals also leads to growth signaling autonomy and tumor progression, so control of growth factor expression may prevent tumor progression. This review describes the role of some of the main growth factors whose dysregulation promotes liver tumor progression, and are also key in regenerating the remaining liver following resection. We herein summarize and discuss studies focused on partial hepatectomy and liver carcinogenesis, referring to hepatocyte growth factor, insulin-like growth factor, and epidermal growth factor, as well as their suitability as targets in the treatment of hepatocellular carcinoma. Finally, and given that drugs remain one of the mainstay treatment options in liver carcinogenesis, we have reviewed the current pharmacological approaches approved for clinical use or research targeting these factors.Ministerio de Ciencia, Innovacion y Universidades Madrid, Spain RTI2018-095114-B-I00European Union (Fondos FEDER, "una manera de hacer Europa")General ElectricSecretaria d' Universitats I Recerca del Departament d' Economia I Coneixement Barcelona, Spain 2017_SGR_551COST action Programs CA17103 CA17112 CA17121 CA17126Consejo Nacional de Ciencia y Tecnologia (CONACyT)Fondo Sectorial de Investigacion para la Educacion, Mexico 257743FCT (Fundacio Catalana de Trasplantament), Spai

    Diagnosis of cardiac surgery-associated acute kidney injury: State of the art and perspectives

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    Producción CientíficaDiagnosis of cardiac surgery-associated acute kidney injury (CSA-AKI), a syndrome of sudden renal dysfunction occurring in the immediate post-operative period, is still sub-optimal. Standard CSA-AKI diagnosis is performed according to the international criteria for AKI diagnosis, afflicted with insufficient sensitivity, specificity, and prognostic capacity. In this article, we describe the limitations of current diagnostic procedures and of the so-called injury biomarkers and analyze new strategies under development for a conceptually enhanced diagnosis of CSA-AKI. Specifically, early pathophysiological diagnosis and patient stratification based on the underlying mechanisms of disease are presented as ongoing developments. This new approach should be underpinned by process-specific biomarkers including, but not limited to, glomerular filtration rate (GFR) to other functions of renal excretion causing GFR-independent hydro-electrolytic and acid-based disorders. In addition, biomarker-based strategies for the assessment of AKI evolution and prognosis are also discussed. Finally, special focus is devoted to the novel concept of pre-emptive diagnosis of acquired risk of AKI, a premorbid condition of renal frailty providing interesting prophylactic opportunities to prevent disease through diagnosis-guided personalized patient handling. Indeed, a new strategy of risk assessment complementing the traditional scores based on the computing of risk factors is advanced. The new strategy pinpoints the assessment of the status of the primary mechanisms of renal function regulation on which the impact of risk factors converges, namely renal hemodynamics and tubular competence, to generate a composite and personalized estimation of individual risk.Instituto de Salud Carlos III y Fondo Europeo de Desarrollo Regional (FEDER) - (grant PI18/00996, PI21/01226), Unión Europea, Red de Investigación Renal (Enfermedad Renal) - (grant RICORS2040)Unión Europea–NextGenerationEU, Mecanismo para la Recuperación y la Resiliencia (MRR) - (grant RD21/0005/0004)Junta de Castilla y León (Consejería de Educación) y Fondo Europeo de Desarrollo Regional (FEDER) - (grant IES160P20

    Autologous bone marrow expanded mesenchymal stem cells in patellar tendinopathy: protocol for a phase I/II, single-centre, randomized with active control PRP, double-blinded clinical trial

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    Introduction: Patellar tendon overuse injuries are common in athletes. Imaging may show a change in tissue structure with tendon thickening and disruption of the intratendinous substance. We wish to test the hypothesis that both autologous bone marrow expanded mesenchymal stem cells and autologous leukocyte-poor platelet-rich plasma (LP-PRP) implanted into the area of the disrupted tendinopathic patellar tendon will restore function, but tendon regeneration tissue will only be observed in the subjects treated with autologous bone marrow expanded mesenchymal stem cells. Methods and analysis: This is a single-centre, pilot phase I/II, double-blinded clinical trial with randomisation with active control. Twenty patients with a diagnosis of patellar tendinopathy with imaging changes (tendon thickening and disruption of the intratendinous substance at the proximal portion of the patellar tendon) will be randomised in a 1:1 ratio to receive a local injection of either bone-marrow autologous mesenchymal stem cells (MSC), isolated and cultured under GMP at The Institute of Biology and Molecular Genetics (IBGM) (Spain) or P-PRP. The study will have two aims: first, to ascertain whether a clinically relevant improvement after 3, 6 and 12 months according to the visual analogue scale (VAS), Victorian Institute of Sport Assessment for patellar tendons (VISA-P) and dynamometry scales (DYN) will be achieved; and second, to ascertain whether the proposed intervention will restore tendon structure as determined by ultrasonography (US), Doppler ultrasonography (DUS), and innovative MRI and ultrasound techniques: Magnetic Resonance T2 FAT SAT (UTE, Ultrashort Echo TE) sequence and Ultrasound Tissue Characterization (UTC). Patients who are randomised to the P-PRP treatment group but do not achieve a satisfactory primary endpoint after 6 months will be offered treatment with MSC

    Resemblance of the human liver sinusoid in a fluidic device with biomedical and pharmaceutical applications

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    Maintenance of the complex phenotype of primary hepatocytes in vitro represents a limitation for developing liver support systems and reliable tools for biomedical research and drug screening. We herein aimed at developing a biosystem able to preserve human and rodent hepatocytes phenotype in vitro based on the main characteristics of the liver sinusoid: unique cellular architecture, endothelial biodynamic stimulation, and parenchymal zonation. Primary hepatocytes and liver sinusoidal endothelial cells (LSEC) were isolated from control and cirrhotic human or control rat livers and cultured in conventional in vitro platforms or within our liver-resembling device. Hepatocytes phenotype, function, and response to hepatotoxic drugs were analyzed. Results evidenced that mimicking the in vivo sinusoidal environment within our biosystem, primary human and rat hepatocytes cocultured with functional LSEC maintained morphology and showed high albumin and urea production, enhanced cytochrome P450 family 3 subfamily A member 4 (CYP3A4) activity, and maintained expression of hepatocyte nuclear factor 4 alpha (hnf4α) and transporters, showing delayed hepatocyte dedifferentiation. In addition, differentiated hepatocytes cultured within this liver-resembling device responded to acute treatment with known hepatotoxic drugs significantly different from those seen in conventional culture platforms. In conclusion, this study describes a new bioengineered device that mimics the human sinusoid in vitro, representing a novel method to study liver diseases and toxicology

    Structure des grands bassins glaciaires dans le nord de la péninsule ibérique: comparaison entre les vallées d'Andorre (Pyrénées orientales), du Gállego (Pyrénées centrales) et du Trueba (Chaîne Cantabrique).

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    Les grandes vallées glaciaires de la Péninsule Ibérique sont situées dans la chaîne pyrénéo-cantabrique, principalement dans le bassin de l'Èbre. Ainsi, les vallées d'Andorre, de la Noguera Pallaresa et de la haute vallée du Gállego, dans les Pyrénées, ont eu des appareils glaciaires longs de 42, 50 et 40 km respectivement. Dans les vallées du Sil (bassin du Miño) et du Trueba, dans la Chaîne Cantabrique, ils atteignaient 42 et 16,5 km (Serrano-Cañadas, 1996 ; Gómez-Ortiz et al., 2001 ; Turu & Peña, 2006a et b ; Redondo-Vega et al., 2006). L'une des caractéristiques géomorphologiques de la plupart de ces vallées est l'existence d'une dépression morphologique du substratum dans les parties moyennes et terminales, interprétée comme la conséquence de l'érosion glaciaire. Dans tous les cas, on observe une architecture litho-stratigraphique commune (Vilaplana & Casas, 1983 ; Bordonau et al., 1989 ; Bordonau, 1992 ; Turu et al., 2002) représentée par trois unités géoélectriques : une unité inférieure très épaisse, avec des résistivités électriques basses (70 - 200 Ohms par mètre), qui traduit la présence de matériaux fins considérés comme d'origine lacustre ; une unité intermédiaire, moins épaisse, avec des valeurs de résistivité plus élevées (400 - 800 Ohms par mètre), pouvant être interprétée comme un système fluvio-deltaïque pro-glaciaire et une unité géoélectrique supérieure, avec des valeurs de résistivité très variables (100 - 1500 Ohms par mètre), constituée de sédiments alluviaux subactuels. La comparaison des données de type géophysique et géomécanique (sismique à réfraction et essais pressiométriques) montre que l'unité intermédiaire, considérée comme d'origine fluvio-deltaïque, présente des valeurs de vitesse sismique anormalement élevées, ainsi que de hautes valeurs de consolidation. Cette observation effectuée pour la première fois dans la vallée d'Andorre (Turu, 2000) montre des remarquables corrélations entre les hautes vitesses sismiques et les valeurs élevées de consolidation, ainsi que la très nette corrélation entre les hautes valeurs de consolidation et les tills sous-glaciaires. Elle permet d'interpréter l'unité intermédiaire comme essentiellement glaciaire et de remettre en question le modèle simple d'une séquence de comblement lacustre et deltaïque proposé jusqu´à maintenant

    Conditional BDNF delivery from astrocytes rescues memory deficits, spine density and synaptic properties in the 5xFAD mouse model of Alzheimer disease

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    It has been well documented that neurotrophins, including brain-derived neurotrophic factor (BDNF), are severely affected in Alzheimer's disease (AD), but their administration faces a myriad of technical challenges. Here we took advantage of the early astrogliosis observed in an amyloid mouse model of AD (5xFAD) and used it as an internal sensor to administer BDNF conditionally and locally. We first demonstrate the relevance of BDNF release from astrocytes by evaluating the effects of coculturing WT neurons and BDNF-deficient astrocytes. Next, we crossed 5xFAD mice with pGFAP:BDNF mice (only males were used) to create 5xFAD mice that overexpress BDNF when and where astrogliosis is initiated (5xF:pGB mice). We evaluated the behavioral phenotype of these mice. We first found that BDNF from astrocytes is crucial for dendrite outgrowth and spine number in cultured WT neurons. Double-mutant 5xF:pGB mice displayed improvements in cognitive tasks compared with 5xFAD littermates. In these mice, there was a rescue of BDNF/TrkB downstream signaling activity associated with an improvement of dendritic spine density and morphology. Clusters of synaptic markers, PSD-95 and synaptophysin, were also recovered in 5xF:pGB compared with 5xFAD mice as well as the number of presynaptic vesicles at excitatory synapses. Additionally, experimentally evoked LTP in vivo was increased in 5xF:pGB mice. The beneficial effects of conditional BDNF production and local delivery at the location of active neuropathology highlight the potential to use endogenous biomarkers with early onset, such as astrogliosis, as regulators of neurotrophic therapy in AD.SIGNIFICANCE STATEMENT Recent evidence places astrocytes as pivotal players during synaptic plasticity and memory processes. In the present work, we first provide evidence that astrocytes are essential for neuronal morphology via BDNF release. We then crossed transgenic mice (5xFAD mice) with the transgenic pGFAP-BDNF mice, which express BDNF under the GFAP promoter. The resultant double-mutant mice 5xF:pGB mice displayed a full rescue of hippocampal BDNF loss and related signaling compared with 5xFAD mice and a significant and specific improvement in all the evaluated cognitive tasks. These improvements did not correlate with amelioration of β amyloid load or hippocampal adult neurogenesis rate but were accompanied by a dramatic recovery of structural and functional synaptic plasticity
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