2,283 research outputs found

    Isolation of epithelial cells, villi and crypts from small intestine of pigeons (Columba livia)

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    The isolation of viable enterocytes, villi and crypts from the small intestine of a feral bird (Columba livia) is important for performing physiological experiments in ecologically relevant processes of membrane transport. The effectiveness of mechanical disruption, enzymatic digestion and chelating agents were compared. The objectives were to isolate enterocytes, villi and crypts from the small intestine of young pigeons; to evaluate the viability of the isolated intestinal epithelial cells isolated; and to verify the integrity of enterocytes by biochemical features. Enzymatic and mechanical methods yielded both elongated columnar and spherical cells. With the chelating method villi and crypts were obtained. All methods produced a high yield of intestinal epithelial cells with about 50 % viability. Brush border enzymes (sucrase-isomaltase and alkaline phosphatase) activities were high and, as reported in chickens, they did not differ along the intestinal villus-crypt axis. Although the three methods have good viabilities, the enzymatic technique gives the best yield in cell number, while the chelating method provides the highest populations of morphologically distinctive villi and crypts.Fil: Mac Donal, Oscar. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; ArgentinaFil: Chediack, Juan Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

    Analytical methods for exploring nutraceuticals based on phenolic acids and polyphenols

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    Phenolic compounds such as phenolic acids, flavonoids, and stilbenes comprise an enormous family of bioactive molecules with a range of positive properties, including antioxidant, antimicrobial or anti-inflammatory effects. As a result, plant extracts are often purified to recover phenolic com-pound enriched fractions to be used to develop nutraceutical products or dietary supplements. In this article, we review the properties of some remarkable plant-based nutraceuticals in which the active molecules are mainly polyphenols and related compounds. Methods for the characterization of these extracts, the chemical determination of the bioactivities of key molecules, and the principal applications of the resulting products will be discussed in detail

    Error control in simplification before generation algorithms for symbolic analysis of large analogue circuits

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    Circuit reduction is a fundamental first step in addressing the symbolic analysis of large analogue circuits. A new algorithm for simplification before generation is presented which is very efficient in terms of speed and the amount of circuit reduction, and solves the accuracy problems of previously reported approaches

    An error-controlled methodology for approximate hierarchical symbolic analysis

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    Limitations of existing approaches for symbolic analysis of large analog circuits are discussed. To address their solution, a new methodology for hierarchical symbolic analysis is introduced. The combination of a hierarchical modeling technique and approximation strategies, comprising circuit reduction, graph-based symbolic solution of circuit equations and matrix-based error control, provides optimum results in terms of speech and quality of results.European Commission ESPRIT 21812Comisión Interministerial de Ciencia y Tecnología TIC97-058

    Total polyphenol content in food samples and nutraceuticals: antioxidant indices versus high performance liquid chromatography

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    The total content of polyphenols and the antioxidant capacity have been estimated in various food and nutraceutical samples including cranberry, raspberry, artichoke, grapevine, green tea, coffee, turmeric, and other medicinal plant extracts. Samples have been analyzed by using two antioxidant assays ¿ferric reducing antioxidant power (FRAP) and Folin-Ciocalteu (FC)¿ and reversed-phase high-performance liquid chromatography (HPLC) focused on providing compositional fingerprints dealing with polyphenolic compounds. A preliminary data exploration by Principal Component Analysis (PCA) has revealed that HPLC fingerprints are suitable chemical descriptors to classify the analyzed samples according to their nature. Besides, chromatographic data have been correlated with antioxidant data using partial least squares (PLS) regression. Regression models have shown a good prediction capacity to estimate the antioxidant activity from chromatographic data, with determination coefficients (R2) of 0.971 and 0.983 for FRAP and FC assays, respectively

    Endoscopic lateral parathyroidectomy as surgical treatment for patients with primary hyperparathyroidism

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    Antecedentes La mayoría de los cirujanos han aceptado de una manera rápida, la realización de miniprocedimientos abiertos para el tratamiento del hiperparatiroidismo primario. Sin embargo, la utilización de la endoscopia cervical sigue siendo discutible por su dificultad técnica y la estricta selección de los pacientes. Material y métodos Entre los meses de abril del 2010 y del 2013, se incluyó a pacientes con hiperparatiroidismo primario esporádico (sPHPT), que además tenían un adenoma único tanto por ecografía y exploración con sestamibi, y que aceptaron participar en el estudio. Los pacientes fueron operados por cirujanos especialmente entrenados en este tipo de cirugía, utilizando la misma técnica quirúrgica en todos ellos. Se recogieron variables demográficas y características clínicas de los pacientes. Una vez finalizada la recolección de información se procedió al análisis descriptivo de las variables (mediana, desviación estándar y rango). Resultados Realizamos un total de 28 paratiroidectomías mediante el abordaje de paratiroidectomía lateral endoscópica. La edad media de los pacientes fue de 68 años (59-89). Todos los pacientes tuvieron un hiperparatiroidismo primario esporádico. No se detectaron complicaciones intraoperatorias. La morbilidad fue comparable con la que muestran series publicadas en técnica abierta. Tras una mediana de seguimiento de 22 (9-53) meses, hemos detectado que el éxito de la intervención ha sido de 27/28 (96%). Conclusiones El abordaje endoscópico del hiperparatiroidismo primario sPHPT resulta factible, reproducible y ofrece unos resultados comparables al abordaje clásico abierto, diversos factores hacen poco recomendable su realización fuera de hospitales con alto volumen de pacientes y unidades diferenciadas de Cirugía Endocrina

    Miocardiopatía por estrés inducida por infarto agudo de miocardio sin lesiones ateroescleróticas

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    El síndrome de takotsubo o miocardiopatía por estrés es una entidad de reciente identificación, caracterizada por trastornos reversibles de la motilidad miocárdica desencadenados por estrés físico o emocional, habitualmente afecta a mujeres añosas y típicamente angiografía coronaria sin lesiones coronarias significativas. Es una entidad que puede mimetizar características de presentación con un síndrome coronario agudo, por lo que su identificación es importante para definir tratamiento específico y pronóstico de los pacientes. Se presenta el caso de una paciente que presentó un shock cardiogénico por miocardiopatía por estrés secundario a un infarto agudo de miocardio por trombo intracoronario.Takotsubo syndrome or stress cardiomyopathy is a recently identified entity, characterized by reversible disorders of myocardial motility triggered by physical or emotional stress, usually affecting older women and typically coronary angiography without significant coronary lesions. It is an entity that can mimic presentation characteristics with an acute coronary syndrome, so its identification is important to define specific treatment and prognosis of patients. We present the case of a patient who presented cardiogenic shock due to stress cardiomyopathy secondary to an acute myocardial infarction due to intracoronary thrombus.Fil: Adaro, Diego. Hospital El Carmen (Mendoza, Argentina). Servicio de CardiologíaFil: Vera, Celeste. Hospital El Carmen (Mendoza, Argentina). Servicio de CardiologíaFil: Alvarado, Juan Sebastián. Hospital El Carmen (Mendoza, Argentina). Servicio de CardiologíaFil: Vidal, Oscar. Hospital El Carmen (Mendoza, Argentina). Servicio de CardiologíaFil: Valente, Roberto. Hospital El Carmen (Mendoza, Argentina). Servicio de Cardiologí

    Environmental and socioeconomic factors of abandonment of rainfed and irrigated crops in northeast Spain

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    Changes over the last century in the economic model of European countries and the development of the market economy have led to intense shifts in land occupation patterns. Agricultural abandonment is an important consequence of these processes and has modified natural and cultural landscapes, involving side-effects for society. Understanding how environmental and socio-economic factors influence the abandonment process can provide useful insights for managing investments, whether from the public or the private sector. In Spain, the Pyrenees and the Ebro Depression are two differentiated areas in terms of land-use dynamics, particularly in terms of the agricultural model carried out. In this paper we have analyzed the agricultural abandonment in these areas during the 1987-2012 period in relation to several potential explanatory factors. The analysis focuses on the abandonment of rainfed and irrigated herbaceous crops in order to derive specific explanations according to the crop type and geographical region. Crop covers were classified from four Landsat scenes, and conditions were described by topographic variables, human factors and drought occurrence. Boosted regression trees (BRT) were used to identify the most important variables and to describe the relationships between agricultural abandonment and key factors. Topography derived variables were found to be the main determinants, except for irrigated crops in the Ebro Basin, where locational factors play a more important role. BRT models allowed us to identify other significant patterns such as: the vulnerability of irrigated crops to drought; the higher dependence of agricultural activity in the Pyrenees on internal networks; pattern shifts of land abandonment in the analyzed sub-periods, and; evidence of the importance of economic diversification for maintaining cropland

    Pheochromocytoma as a rare cause of arterial hypertension in a patient with autosomal dominant polycystic kidney disease: A diagnostic and therapeutic dilemma.

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    INTRODUCTION: Individuals with autosomal dominant polycystic kidney disease (ADPKD) frequently suffer arterial hypertension even prior to significant loss of renal function, a clinical situation that obscures detection of modifiable secondary causes of hypertension. PRESENTATION OF CASE: A 50-year-old man with ADPKD and polycystic liver and resistant hypertension is diagnosed with a 4-cm right adrenal mass. Cross-sectional MRI is indicative of pheochromocytoma versus adrenocortical carcinoma or metastasis, though there are no typical PCC symptoms and plasma and urine metanephrines are within normal ranges. Since malignancy cannot be excluded, right adrenalectomy is performed. Considering that the enlarged liver poses an obstacle for transperitoneal open and laparoscopic approaches, a retroperitoneoscopic approach is used. Surgical pathology reveals a 4.5-cm pheochromocytoma; the patient no longer requires antihypertensive therapy. DISCUSSION & CONCLUSION: Pheochromocytoma is a rare but treatable cause of hypertension in ADPKD; given the anatomical complexities these patients present, careful preoperative planning and surgical technique are essential to a favorable outcome

    Towards automated composition of convergent services: A survey

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    A convergent service is defined as a service that exploits the convergence of communication networks and at the same time takes advantage of features of the Web. Nowadays, building up a convergent service is not trivial, because although there are significant approaches that aim to automate the service composition at different levels in the Web and Telecom domains, selecting the most appropriate approach for specific case studies is complex due to the big amount of involved information and the lack of technical considerations. Thus, in this paper, we identify the relevant phases for convergent service composition and explore the existing approaches and their associated technologies for automating each phase. For each technology, the maturity and results are analysed, as well as the elements that must be considered prior to their application in real scenarios. Furthermore, we provide research directions related to the convergent service composition phases
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