2,350 research outputs found

    Genomics helps to decipher the resistance mechanisms present in a Pseudomonas chlororaphis strain recovered in an HIV patient

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    Fil: Montaña, Sabrina Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Lazzaro, T.. California State University; Estados UnidosFil: Uong, S.. California State University; Estados UnidosFil: Place, K.. California State University; Estados UnidosFil: Iriarte, A.. Universidad de la República; UruguayFil: Ocampo, C. V.. Sanatorio Mater Dei; ArgentinaFil: Vay, C.. Sanatorio Mater Dei; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Ramírez, M. S.. California State University; Estados Unido

    ATAC-clock: An aging clock based on chromatin accessibility.

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    The establishment of aging clocks highlighted the strong link between changes in DNA methylation and aging. Yet, it is not known if other epigenetic features could be used to predict age accurately. Furthermore, previous studies have observed a lack of effect of age-related changes in DNA methylation on gene expression, putting the interpretability of DNA methylation-based aging clocks into question. In this study, we explore the use of chromatin accessibility to construct aging clocks. We collected blood from 159 human donors and generated chromatin accessibility, transcriptomic, and cell composition data. We investigated how chromatin accessibility changes during aging and constructed a novel aging clock with a median absolute error of 5.27 years. The changes in chromatin accessibility used by the clock were strongly related to transcriptomic alterations, aiding clock interpretation. We additionally show that our chromatin accessibility clock performs significantly better than a transcriptomic clock trained on matched samples. In conclusion, we demonstrate that the clock relies on cell-intrinsic chromatin accessibility alterations rather than changes in cell composition. Further, we present a new approach to construct epigenetic aging clocks based on chromatin accessibility, which bear a direct link to age-related transcriptional alterations, but which allow for more accurate age predictions than transcriptomic clocks

    Improved Bovine Blastocyst Developmental Potential by L-carnitine Supplementation

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    Abstract. In this study, the potential role of L-carnitine supplementation in the maturation of oocytes and pre-implantation development of embryos was investigated using bovine as a model. In Experiment 1, bovine oocytes recovered from the abattoir were matured in the absence (control) or presence of L-carnitine, subjected to in vitro fertilization and assessed on their developmental potential up to the blastocyst stage. The nuclear maturation and cleavage rate observed between the control and L-carnitine supplemented group ranged from 83.1% -87.1% and 57.1% -67.9%, respectively. Significantly higher blastocyst formation rate and improved total cell count in 0.1-0.5 mg/ml L-carnitine supplemented groups were observed versus the control (51.0 -54.2% vs 29.5% and 97.4 -110.1 ± 2.2 vs 82.5 ± 1.6, respectively (P<0.05). In Experiment 2, zygotes resulting from in vitro fertilization of bovine oocytes were cultured in modified synthetic oviductal fluid medium with or without L-carnitine supplementation. Results showed no significant difference on the blastocyst formation rate among treatment groups, but the total cell count of blastocyst derived from 0.1 -0.5 mg/ml L-carnitine supplemented groups were higher than the control (98.4 -115.4 ± 3.1 vs 84.6 ± 3.2, respectively (P<0.05). Overall, the results demonstrated the usefulness of the procedures utilized in the maturation, fertilization and culture of bovine oocytes and early-stage embryos. That, L-carnitine supplementation at the level of 0.1 -0.5 mg/ml concentration in the maturation and culture media tend to enhance the developmental potential of oocytes and early-stage embryos to the blastocyst stage as indicated by a higher total cell count (improved cell activity)

    Sobrevida y análisis de coste-efectividad de los dispositivos de asistencia ventricular izquierda en pacientes con insuficiencia cardíaca avanzada: un análisis bibliométrico

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    Introduction and objective: Left ventricular assist devices (LVADs) used as bridging therapy for heart transplantation or as a definitive treatment in patients with advanced heart failure have shown benefit by improving functional class and quality of life indicators of patients, without However, today we do not know with certainty the cost- effectiveness analysis of this technology and its impact on survival. For this reason we decided to perform a bibliometric analysis in order to answer this question and open the possibility of new research proposals on this topic. Methodology: Retrospective bibliometric analysis, descriptive type. A MEDLINE search was performed using GoPubMed and FABUMED with the following search strategy: cardiac insufficiency and left ventricular assist devices and cost-effectiveness and survival Y (2000: 2017 [dp]. Results: 27 indexed references were obtained in 20 different journals. International Journal of Cardiology, Heart and Lung Transplantation Review, Health Technology Assessment, Circulation: Cardiac Insufficiency and International Journal of Technological Assessment in Health Care (30%). The continent with the largest number of publications was America (specifically North America) with 16 publications (59.3%), followed by Europe with 10 publications (37%) and Oceania with 1 publication (3.7%), Suramerica so far has no publications. There is a growing pattern in the number of publications in the last 5 years compared to the previous 13 years, with a total production of 12 articles (44.4%), in 2017 with 2 publications (7.4%), 2016 with 1 publication (3.7%), 2014 with 4 publications (14.8%) and 2013 with 5 publications (18.5%). Conclusions: The number of publications on cost-effectiveness and survival on the use of left ventricular assist devices in the management of patients with heart failure has observed a direct relationship between the development index of each country and its scientific production. However, to date there are no indexed publications in South America and we recognize the importance of the topic in our region.Antecedentes y objetivo: Los dispositivos de asistencia ventricular izquierda (LVADs) empleados como terapia-puente al trasplante cardíaco o como tratamiento definitivo en el paciente con insuficiencia cardíaca avanzada, han demostrado beneficio al mejorar la clase funcional y los indicadores de calidad de vida de los pacientes; sin embargo, hoy en día se desconoce con certeza la coste-efectvidad de esta tecnología y su impacto en la sobrevida. Por esta razón se realiza un análisis bibliométrico con el fin de contestar este interrogante y abrir la posibilidad de nuevas propuestas de investigación en este tema. Materiales y métodos: Análisis bibliométrico retrospectivo, de tipo descriptivo. Se realizó una búsqueda bibliográfica en MEDLINE utilizando GoPubMed y FABUMED con la siguiente estrategia de búsqueda: heart failure AND left ventricular assist devices AND cost- effectivenessAND survival AND (2000:2017[dp]. Resultados: Se obtuvieron 27 referencias indexadas en 20 revistas diferentes. Las revistas con mayor número de publicaciones fueron 6, de las cuales 5 tenían dos publicaciones cada una y solo una con 3 publicaciones: Ontario Health Technology Assessment Series, International Journal of Cardiology, The Journal of Heart and Lung Transplantation, Health Technology Assessment, Circulation: Heart Failure e International Journal of Technology Assessment in Health Care (30%). El continente con mayor número de publicaciones fue América (específicamente Norteamérica) con 16 publicaciones (59,3%), seguido por Europa con 10 (37%) y Oceanía con 1 publicación (3,7%). Suramérica hasta el momento no cuenta con ninguna publicación. Se observó un patrón creciente en el número de publicaciones de los últimos 5 años comparado con los 13 años anteriores, con una producción total de 12 artículos (44,4%): en el año 2017 con 2 publicaciones (7,4%), 2016 con 1 (3,7%), 2014 con 4 (14,8%) y 2013 con 5 publicaciones (18,5%). Conclusiones: El número de publicaciones sobre coste-efectividad y sobrevida acerca del uso de dispositivos de asistencia ventricular izquierda en el manejo de pacientes con insuficiencia cardíaca avanzada, ha crecido en los últimos cinco años, observándose una relación directa entre el índice de desarrollo de cada país y su producción científica. Sin embargo, hasta el momento no hay publicaciones indexadas en Suramérica y se reconoce la importancia del tema en nuestra región

    The problem of endosulfan: chemical, analytical and environmental issues

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    Introducción. Dado el carácter residual y el alto nivel de toxicidad del endosulfán, se ha incrementado la preocupación a nivel mundial por su impacto ambiental. Por eso la búsqueda de metodologías analíticas que permitan su detección y cuantificación es un tema de investigación vigente. Las propiedades del endosulfán y su patrón de degradación le confieren características que hacen muy compleja la problemática, al tiempo que el pesticida y sus metabolitos se expanden extensivamente por la atmósfera y contaminan tanto matrices lipofílicas como hidrofílicas. Objetivo. Llevar a cabo una revisión sobre las investigaciones más recientes acerca de la problemática del endosulfán, que incluye aspectos químicos, su problemática ambiental y técnicas inmunoquímicas para su análisis, tema en el que ha estado interesado nuestro grupo de investigación en la Universidad de Caldas. Método. El presente artículo de revisión analiza, cualitativamente, la literatura científica disponible en las bases de datos Science Direct, PubMed, Scielo y páginas Web oficiales, empleando como palabras de búsqueda: endosulfán, haptenos, análisis inmunoquímico del endosulfán, problemática ambiental del endosulfán, regulaciones internacionales sobre el endosulfán, normatividad vigente sobre el endosulfán, y métodos instrumentales de análisis. Resultados. Se obtuvo información pertinente relacionada con el objetivo propuesto, la cual se presenta en 3 secciones: aspectos químicos del endosulfán, problemática ambiental y técnicas inmoquímicas para su análisis. Conclusión. El endosulfán ha sido prohibido por los organismos internacionales. Sin embargo, el pesticida se continúa usando en algunos países y éste se difunde fácilmente hacia otras regiones, de tal manera que se ha convertido en un problema global. Hay investigaciones recientes sobre métodos de remediación química o biológica, pero los esfuerzos son modestos frente a la enorme problemática de este pesticida. En lo pertinente a análisis químicos de endosulfán, en los últimos 15 años se han investigado técnicas inmunoquímicas de análisis (basadas en haptenos), como alternativa a los métodos cromatográficos instrumentales.Introduction. Due to the residual character and high level of toxicity of endosulfan, worldwide concern for its environmental impact has increased. Therefore, the search for analytical methodologies that allow its detection and quantification continues to be a topic of current research. Endosulfan properties and its degradation pattern confer it characteristics that make very complex the problematic while the pesticide and its metabolites are extensively spread throughout the atmosphere and contaminate both lipophilic and hydrophilic matrixes. Objective. To conduct a review on some recent research about the endosulfan problematic including chemical aspects, environmental issues and immunochemical techniques for its analysis, which is an area of current interest in this research group at Universidad de Caldas. Method. This review article  analyzes qualitatively scientific literature from ScienceDirect, PubMed, Scielo  databases and official Web pages using key words such as endosulfan, endosulfan immunochemical analysis, endosulfan environmental problematic, endosulfan international regulations, endosulfan current normativity and instrumental methods for the analysis. Results. Relevant information related to the proposed objective was found which is presented in 3 sections: chemical aspects of endosulfan, environmental issues, and immunochemical techniques for its analysis. Conclusions. Endosulfan has been banned by international organizations. However, the pesticide is still being used in some countries and is easily spread to other regions, so that the problem became a global concern. There is some recent research on biological or chemical remediation techniques, but efforts seem insufficient in comparison to the enormous impact of the pesticide. In regard to Endosulfan chemical analyses, during the past 15 years immunochemical haptenbased analysis techniques have been investigated as alternatives to the instrumental chromatographic methods

    Estudio comparativo de parámetros composicionales y nutricionales en leche de vaca, cabra y búfala, Antioquia, Colombia

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    Milk is a fluid secreted by females of all species of mammals, which is used mainly to supply the nutritional needs of the newborn calf. It is an important source of carbohydrates, lipids, proteins, vitamins and minerals. Throughout history many countries have characterized the composition and nutritional quality of many mammals species milk, especially those that have been domesticated. However in Colombia there is insufficient information with respect to milk produced by different species to the cow. The aim of this study was to determine the composition and evaluate the nutritional quality of cow, goat and buffalo milk. Buffalo milk showed higher values in for parameters such as protein (4,07%), fat (7,23%), lactose (5,06%), total solids (16,81%) and solids non-fat (9,91%) than goat and cow milk, making it an excellent alternative for the production and processing of milk products. On the other hand goat milk had the highest content of polyunsaturated fat (0.1298 g/100g) compared to cow milk and buffalo milk, which makes it more digestible and healthy for human consumption. All this led to the conclusion that each of these milk types has particular characteristics that make them more or less digestible and suitable for the manufacture of dairy products, which determines the advantages and disadvantages of each of the species.La leche es un líquido secretado por las hembras de todas las especies de mamíferos, la cual es utilizada principalmente para satisfacer las necesidades nutricionales de la cría recién nacida. Es una fuente importante de carbohidratos, lípidos, proteínas, vitaminas y minerales. A lo largo de la historia en varios países se ha caracterizado la composición y calidad nutricional de la leche de numerosas especies de mamíferos, especialmente las que han sido domesticadas. Sin embargo en Colombia no hay suficiente información en lo que respecta a leches producidas por especies no vacunas. El objetivo del presente estudio fue determinar la composición y evaluar la calidad nutricional de las leches de vaca, cabra y búfalo. La leche de búfala presento valores más altos para parámetros tales como la proteína (4,07%), grasa (7,23%), lactosa (5,06%), solidos totales (16,81%) y solidos no grasos (9,91%) que las leches de cabra y vaca, lo cual la convierte en una excelente alternativa para la producción y transformación de productos. De otro lado la leche de cabra presento el mayor contenido de grasa poliinsaturada (0,1298 g/100g) comparadas con las leches de vaca y búfala, lo que la hace más digestible y saludable para el consumo humano. Todo lo anterior llevó a la conclusión de que cada uno de estos tipos de leche tiene características particulares que las hacen más o menos digestibles y adecuadas para la fabricación de productos lácteos, lo cual determina las ventajas y desventajas de cada una de las especies

    Measuring Terrestrial Area of Habitat (AOH) and Its Utility for the IUCN Red List

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    The International Union for Conservation of Nature (IUCN) Red List of Threatened Species includes assessment of extinction risk for 98 512 species, plus documentation of their range, habitat, elevation, and other factors. These range, habitat and elevation data can be matched with terrestrial land cover and elevation datasets to map the species’ area of habitat (AOH; also known as extent of suitable habitat; ESH). This differs from the two spatial metrics used for assessing extinction risk in the IUCN Red List criteria: extent of occurrence (EOO) and area of occupancy (AOO). AOH can guide conservation, for example, through targeting areas for field surveys, assessing proportions of species’ habitat within protected areas, and monitoring habitat loss and fragmentation. We recommend that IUCN Red List assessments document AOH wherever practical

    SMOS soil moisture product validation in croplands

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    A validation campaign has been carried out to evaluate the Level 2 Soil Moisture (SM) product (version 5.51) given by the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in the Pampean Region of Argentina. The study region was selected because it is a plain, avoiding topography problems, with an SMOS nominal land use class (low vegetation crops, 1-2m height). Transects of ground SM measurements were collected at 5-cm and 6-cm depth using Delta-T ThetaProbe ML2x and Stevens Hydra Probe II SM sensors, respectively. The volumetric measurements were calibrated using gravimetric and bulk density data collected at the same time as the SM sensor measurements. The SM transects covered ISEA-grid SMOS nodes over four extensive agricultural areas with prevalence of soy crops (site 1: -32.982N, -62.505E; site 2: -32.510N, -62.788E; site 3: -32.024N, -63.692E; and site 4: -37.315N, -58.868E, WGS84). The validation sites were selected taking as reference the locations of permanent SM stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE, National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria (INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras (IHLLA, Plain Hydrology Institute). Therefore, additionally to validate the SMOS SM product with the ground data collected during the experimental campaign, the measurements are useful to evaluate the station SM data reliability at the SMOS spatial resolution with the aim of using station data series as reference to test different versions of the SMOS SM product. Previously to the campaign, SMOS SM data variability, ESA Globcover land use classification, soil edaphic properties, water bodies and topography were analyzed around the station locations to select the best sites and the experimental methodology. Temperature vegetation dryness index (TVDI) temporal and spatial variability was also studied at the sites. Additionally, transects of land surface temperature were carried out with Cimel Electronique CE312 6-band radiometers concurrently with thermal-infrared (TIR) satellite overpasses. In previous works, we studied the dependence of land surface emissivities on SM. The analysis of concurrent TIR and SM data make possible to evaluate the utility of the SMOS SM product to improve land surface emissivities and temperature determinations from satellite, giving an added value to the research
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