946 resultados para solution-based DNA extraction
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A lo largo de la historia reciente de Colombia se han establecido distintos mecanismos de participación y representación para los jóvenes en las diferentes esferas de la sociedad. Dichas dinámicas de participación juvenil requieren de la aplicación de distintas herramientas y estrategias de comunicación, que permitan el acceso de los jóvenes en los distintos programas, estrategias y espacios de participación y representación. Sin embargo dado el marco normativo en materia de juventud, esta investigación diagnostica la existencia de un problema de comunicación, sustentado en la falta de conocimiento por parte de los jóvenes de los diversos espacios de participación y representación. Por tal motivo se presentan distintas estrategias y medidas como alternativas de solución, con el objetivo de garantizar que los jóvenes en Colombia ejerzan sus derechos y deberes en materia de participación y representación.
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Introducción: La Enfermedad de Parkinson (EP) fue descrita por primera vez por James Parkinson en 1817, es el segundo desorden neurodegenerativo más frecuente después de la enfermedad de Alzheimer. Los síntomas aparecen por una deficiencia de dopamina causada por la degeneración y perdida de las neuronas dopaminérgicas en diversas regiones del cerebro, principalmente la sustancia nigra. Se sabe actualmente que existen factores genéticos involucrados en el desarrollo de la enfermedad, principalmente en la EP de inicio temprano. Uno de los genes, que según diversos reportes ha sido frecuentemente implicado con el desarrollo de la enfermedad es el gen PARK2 o PRKN que codifica para la proteína Parkina, una proteína de 465 aminoácidos. Se conoce que la proteína Parkina tiene función de ligasa de las proteínas ubiquitinadas; las mutaciones que se han podido identificar en Parkina llevan a la pérdida de su función, reduciendo su capacidad de regular la degradación de sustratos. Metodología: Se realizó un estudio observacional descriptivo de tipo cross sectional.Para ello se evaluaron 29 pacientes diagnosticados con EP de inicio temprano (anterior a los 40 años de edad) y de 21 individuos sanos que se utilizaron como control. Se tomó una muestra de sangre periférica a los pacientes y controles, y se procedió a realizar la extracción de DNA. Posteriormente se estandarizaron las condiciones para la técnica de PCR para la amplificación de los exones 3, 4, y 5 en cada individuo. Todos los productos amplificados se sometieron a secuenciación automática para evaluar posibles mutaciones y polimorfismos en la población de estudio.
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ANTECEDENTES: El aislamiento de células fetales libres o ADN fetal en sangre materna abre una ventana de posibilidades diagnósticas no invasivas para patologías monogénicas y cromosómicas, además de permitir la identificación del sexo y del RH fetal. Actualmente existen múltiples estudios que evalúan la eficacia de estos métodos, mostrando resultados costo-efectivos y de menor riesgo que el estándar de oro. Este trabajo describe la evidencia encontrada acerca del diagnóstico prenatal no invasivo luego de realizar una revisión sistemática de la literatura. OBJETIVOS: El objetivo de este estudio fue reunir la evidencia que cumpla con los criterios de búsqueda, en el tema del diagnóstico fetal no invasivo por células fetales libres en sangre materna para determinar su utilidad diagnóstica. MÉTODOS: Se realizó una revisión sistemática de la literatura con el fin de determinar si el diagnóstico prenatal no invasivo por células fetales libres en sangre materna es efectivo como método de diagnóstico. RESULTADOS: Se encontraron 5,893 artículos que cumplían con los criterios de búsqueda; 67 cumplieron los criterios de inclusión: 49.3% (33/67) correspondieron a estudios de corte transversal, 38,8% (26/67) a estudios de cohortes y el 11.9% (8/67) a estudios casos y controles. Se obtuvieron resultados de sensibilidad, especificidad y tipo de prueba. CONCLUSIÓN: En la presente revisión sistemática, se evidencia como el diagnóstico prenatal no invasivo es una técnica feasible, reproducible y sensible para el diagnóstico fetal, evitando el riesgo de un diagnóstico invasivo.
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Los solventes orgánicos son sustancias químicas que por sus propiedades físico-químicas son fácilmente inhalados o absorbidos por la piel, pueden causar daños de diversa índole en la salud. En Colombia existen normas que contemplan las medidas de protección, sin embargo persiste la informalidad en el sector de pintores de autos, por lo cual los trabajadores expuestos, a largo plazo pueden ver afectada su salud. En este estudio se analizó la relación entre individuos expuestos laboralmente a los solventes orgánicos versus no expuestos con respecto a la longitud de sus telómeros y formación de fragilidades. Se emplearon muestras de sangre extraídas por venopunción, recolectada en dos tubos: uno con Heparina, destinado al cultivo de linfocitos, para obtener cromosomas metafásicos y evaluar en ellos la presencia de fragilidades; el otro tubo con EDTA, fue empleado para la extracción de ADN y se utilizó para obtener los valores de longitud telomérica mediante la técnica de PCR cuantitativa. Los análisis estadísticos se realizaron aplicando la prueba de rangos de Wilcoxon, en el caso de la presencia de fragilidades se analizó la razón No.Fragilidades/No.Metafases, aplicando el método de Wilcoxon se encontró que existe diferencia estadísticamente significativa entre expuestos y no expuestos (p = 0,036), en donde los expuestos presentan mayor frecuencia de fragilidades. Por otra parte el valor relativo de longitud telomérica del grupo de expuestos fue mayor que el observado en el grupo de no expuestos, esta diferencia fue estadísticamente significativa (Wilcoxon, p = 0.002).
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D'entre els defectes organolèptics associats al vi, en destaca l'anomenat "gust de suro" habitualment vinculat a la presència de cloroanisoles, els quals són productes de l'activitat microbiana formats a partir dels corresponents clorofenols. La present tesi doctoral recull, en primer lloc, metodologies analítiques adreçades principalment a la determinació dels compostos clorofenòlics (2,4,6-triclorofenol, 2,3,4,6-tetraclorofenol i pentaclorofenol) en el control de qualitat dels taps suro, emprant dissolucions hidroalcohòliques com a medi de maceració o d'extracció i utilitzant les tècniques d'extracció en fase sòlida (SPE) i microextracció en fase sòlida (SPME) acoblades a la cromatografia de gasos (GC). En segon lloc, per tal de dur a terme l'anàlisi de cloroanisoles juntament amb els seus precursors en matrius de suro s'ha avaluat un mètode basat en l'extracció amb dissolvent orgànic, el qual ha estat aplicat per a l'estudi de diferents sistemes d'eliminació d'aquests anàlits en la matriu citada. En darrer lloc, s'han proposat metodologies per l'anàlisi de mostres de vi, en les quals d'una banda s'han determinat els compostos clorofenòlics utilitzant la SPME i de l'altra el 2,4,6-tricloroanisole i el 2,4,6-tribromoanisole mitjançant l'acoblament de la SPE i la injecció de grans volums (LVI) en el sistema cromatogràfic.
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Real-time PCR protocols were developed to detect and discriminate 11 anastomosis groups (AGs) of Rhizoctonia solani using ribosomal internal transcribed spacer (ITS) regions (AG-1-IA, AG-1-IC, AG-2-1, AG-2-2, AG-4HGI+II, AG-4HGIII, AG-8) or beta-tubulin (AG-3, AG-4HGII, AG-5 and AG-9) sequences. All real-time assays were target group specific, except AG-2-2, which showed a weak cross-reaction with AG-2tabac. In addition, methods were developed for the high throughput extraction of DNA from soil and compost samples. The DNA extraction method was used with the AG-2-1 assay and shown to be quantitative with a detection threshold of 10-7 g of R. solani per g of soil. A similar DNA extraction efficiency was observed for samples from three contrasting soil types. The developed methods were then used to investigate the spatial distribution of R. solani AG-2-1 in field soils. Soil from shallow depths of a field planted with Brassica oleracea tested positive for R. solani AG-2-1 more frequently than soil collected from greater depths. Quantification of R. solani inoculum in field samples proved challenging due to low levels of inoculum in naturally occurring soils. The potential uses of real-time PCR and DNA extraction protocols to investigate the epidemiology of R. solani are discussed.
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1. To understand population dynamics in stressed environments it is necessary to join together two classical lines of research. Population responses to environmental stress have been studied at low density in life table response experiments. These show how the population's growth rate (pgr) at low density varies in relation to levels of stress. Population responses to density, on the other hand, are based on examination of the relationship between pgr and population density. 2. The joint effects of stress and density on pgr can be pictured as a contour map in which pgr varies with stress and density in the same way that the height of land above sea level varies with latitude and longitude. Here a microcosm experiment is reported that compared the joint effects of zinc and population density on the pgr of the springtail Folsomia candida (Collembola). 3. Our experiments allowed the plotting of a complete map of the effects of density and a stressor on pgr. Particularly important was the position of the pgr= 0 contour, which suggested that carrying capacity varied little with zinc concentration until toxic levels were reached. 4. This prediction accords well with observations of population abundance in the field. The method also allowed us to demonstrate, simultaneously, hormesis, toxicity, an Allee effect and density dependence. 5. The mechanisms responsible for these phenomena are discussed. As zinc is an essential trace element the initial increase in pgr is probably a consequence of dietary zinc deficiency. The Allee effect may be attributed to productivity of the environment increasing with density at low density. Density dependence is a result of food limitation. 6. Synthesis and applications. We illustrate a novel solution based on mapping a population's growth rate in relation to stress and population density. Our method allows us to demonstrate, simultaneously, hormesis, toxicity, an Allee effect and density dependence in an important ecological indicator species. We hope that the approach followed here will prove to have general applicability enabling predictions of field abundance to be made from estimates of the joint effects of the stressors and density on population growth rate.
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The problems encountered by individuals with disabilities when accessing large public buildings is described and a solution based on the generation of virtual models of the built environment is proposed. These models are superimposed on a control network infrastructure, currently utilised in intelligent building applications such as lighting, heating and access control. The use of control network architectures facilitates the creation of distributed models that closely mirror both the physical and control properties of the environment. The model of the environment is kept local to the installation which allows the virtual representation of a large building to be decomposed into an interconnecting series of smaller models. This paper describes two methods of interacting with the virtual model, firstly a two dimensional aural representation that can be used as the basis of a portable navigational device. Secondly an augmented reality called DAMOCLES that overlays additional information on a user’s normal field of view. The provision of virtual environments offers new possibilities in the man-machine interface so that intuitive access to network based services and control functions can be given to a user.
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Internal bacterial communities of synanthropic mites Acarus siro, Dermatophagoides farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae (Acari: Astigmata) were analyzed by culturing and culture-independent approaches from specimens obtained from laboratory colonies. Homogenates of surface-sterilized mites were used for cultivation on non-selective agar and DNA extraction. Isolated bacteria were identified by sequencing of the 16S rRNA gene. PCR amplified 16S rRNA genes were analyzed by terminal restriction fragment length polymorphism analysis (T-RFLP) and cloning sequencing. Fluorescence in situ hybridization using universal bacterial probes was used for direct bacterial localization. T-RFLP analysis of 16S rRNA gene revealed distinct species-specific bacterial communities. The results were further confirmed by cloning and sequencing (284 clones). L. destructor and D. farinae showed more diverse communities then A. siro and T. putrescentiae. In the cultivated part of the community, the mean CFUs from four mite species ranged from 5.2 × 102 to 1.4 × 103 per mite. D. farinae had significantly higher CFUs than the other species. Bacteria were located in the digestive and reproductive tract, parenchymatical tissue, and in bacteriocytes. Among the clones, Bartonella-like bacteria occurring in A. siro and T. putresecentiae represented a distinct group related to Bartonellaceae and to Bartonella-like symbionts of ants. The clones of high similarity to Xenorhabdus cabanillasii were found in L. destructor and D. farinae, and one clone related to Photorhabdus temperata in A. siro. Members of Sphingobacteriales cloned from D. farinae and A. siro clustered with the sequences of “Candidatus Cardinium hertigii” and as a separate novel cluster.
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Enterprise Resource Planning is often endorsed as a means to facilitate strategic advantage for businesses. The scarcity of resources is the method by which some businesses maintain their position. However, the ubiquitous trend towards the adoption of Enterprise Resourcing Planning systems coupled with market saturation makes the promise of advantage less compelling. Reported in this paper is a proposed solution based upon semiotic theory that takes a typical Enterprise Resource Planning deployment scenario and shapes it according to the needs of people in post-implementation contexts to leverage strategic advantage in different ways.
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On December 9, 2007, a 4.9 m(b) earthquake occurred in the middle of the Sao Francisco Craton, in a region with no known previous activity larger than 4 m(b). This event reached intensity VII MM (Modified Mercalli) causing the first fatal victim in Brazil. The activity had started in May 25, 2007 with a 3.5 magnitude event and continued for several months, motivating the deployment of a local 6-station network. A three week seismic quiescence was observed before the mainshock. Initial absolute hypocenters were calculated with best fitting velocity models and then relative locations were determined with hypoDD. The aftershock distribution indicates a 3 km long rupture for the mainshock. The fault plane solution, based on P-wave polarities and hypocentral trend, indicates a reverse faulting mechanism on a N30 degrees E striking plane dipping about 40 degrees to the SE. The rupture depth extends from about 0.3 to 1.2 km only. Despite the shallow depth of the mainshock, no surface feature could be correlated with the fault plane. Aeromagnetic data in the epicentral area show short-wavelength lineaments trending NNE-SSW to NE-SW which we interpret as faults and fractures in the craton basement beneath the surface limestone layer. We propose that the Caraibas-Itacarambi seismicity is probably associated with reactivation of these basement fractures and faults under the present E-W compressional stress field in this region of the South American Plate. (c) 2009 Elsevier B.V. All rights reserved.
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Successful classification, information retrieval and image analysis tools are intimately related with the quality of the features employed in the process. Pixel intensities, color, texture and shape are, generally, the basis from which most of the features are Computed and used in such fields. This papers presents a novel shape-based feature extraction approach where an image is decomposed into multiple contours, and further characterized by Fourier descriptors. Unlike traditional approaches we make use of topological knowledge to generate well-defined closed contours, which are efficient signatures for image retrieval. The method has been evaluated in the CBIR context and image analysis. The results have shown that the multi-contour decomposition, as opposed to a single shape information, introduced a significant improvement in the discrimination power. (c) 2008 Elsevier B.V. All rights reserved,
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Human papillomavirus is a DNA virus that includes 118 genotypes. HPV16 is responsible for 80% of cervical cancer in women. Men are important reservoirs and major transmitters of HPV to their partners. The aim of this study was to detect HPV DNA and to determine the prevalence of HPV types 6, 11, 16, and 18 in urine samples of men infected with HIV-1. This study included 223 patients infected with HIV-1 from the Center of Reference on HIV/AIDS (CRT-SP) and an outpatient clinic of HIV. Urine samples were collected and after DNA extraction real-time PCR was performed for detection of HPV DNA. Positive samples were then tested by conventional PCR using type-specific primers for the four HPV types. A total of 223 men infected with HIV-1 were tested, 81% of whom were on HAART. Four (5.8%) were positive for HPV6, 18 (26.1%) were positive for HPV11, 22 (31.9%) were positive for HPV16 and five (7.2%) were positive for HPV18 by conventional PCR. Twenty (29%) patients had other HPV types and five patients (1.5%) had multiple types. The mean T CD4+cells count was 517 and 441 cells/mm(3) (P=0.30), in HPV negative and positive men, respectively. The HIV viral load was higher in the HPV negative group than for in the men with HPV (P=0.0002). A 30.9% prevalence of HPV was found in asymptomatic urine samples of men infected with HIV-1. This study suggests that urine may be a useful specimen for HPV screening. J. Med. Virol 81:2007-2011, 2009. (C) 2009 Wiley-Liss, Inc.
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In this research the 3DVAR data assimilation scheme is implemented in the numerical model DIVAST in order to optimize the performance of the numerical model by selecting an appropriate turbulence scheme and tuning its parameters. Two turbulence closure schemes: the Prandtl mixing length model and the two-equation k-ε model were incorporated into DIVAST and examined with respect to their universality of application, complexity of solutions, computational efficiency and numerical stability. A square harbour with one symmetrical entrance subject to tide-induced flows was selected to investigate the structure of turbulent flows. The experimental part of the research was conducted in a tidal basin. A significant advantage of such laboratory experiment is a fully controlled environment where domain setup and forcing are user-defined. The research shows that the Prandtl mixing length model and the two-equation k-ε model, with default parameterization predefined according to literature recommendations, overestimate eddy viscosity which in turn results in a significant underestimation of velocity magnitudes in the harbour. The data assimilation of the model-predicted velocity and laboratory observations significantly improves model predictions for both turbulence models by adjusting modelled flows in the harbour to match de-errored observations. 3DVAR allows also to identify and quantify shortcomings of the numerical model. Such comprehensive analysis gives an optimal solution based on which numerical model parameters can be estimated. The process of turbulence model optimization by reparameterization and tuning towards optimal state led to new constants that may be potentially applied to complex turbulent flows, such as rapidly developing flows or recirculating flows.
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The Human Papillomavirus (HPV) infection is the major sexually transmitted disease all over the world. There are many factors associated to infection and the virus persistency in the organism. This study aims to evaluate the women's knowledge, attitudes and practice about the Papanicolaou test (Pap), as well as analyze the HPV and Chlamydia trachomatis infections prevalences in sexually active women from the city of São José do Mipibu/RN/Brazil. This research was divided in two steps (step I and step II), using different methodologies and samples each. The samples collected in each step, even socio-demographic or from uterus cervix, are from different patients e were analyzed separated. In step I was evaluated 267 rural and urban zone women s knowledge, attitudes and practices about the Pap by home interview. In the step II were included 605 women with age ranged from 15 to 71 years old, with mean of 33,5 years old and from each one were collected two cervical samples, one for Pap and other for molecular biology, beside the epidemiological interview to investigate the correlation between prevalence of HPV infection and risk factors. To molecular analyses, the samples were processed using a mammal rapid DNA extraction technique protocol. For C. trachomatis DNA detection were used the CP24/27 primers, and GP5+/GP6+ to HPV. PCR products were analyzed by electrophoresis on 8% polyacrylamide gels, followed by silver staining. The results of the step I showed that, in spite of only 46,1% of the interviewed women they have demonstrated to possess appropriate knowledge on the Pap test, the attitude and practice proportions were significantly larger, 63,3% and 64,4% respectively. The largest education degree presented association with adaptation of the knowledge, attitudes and practice, while neglect, lack of solicitation of the exam for the doctor and shame, came as main barriers for the accomplishment of the exam. In the stage II the HPV general prevalence was 28,9%, being 26,7% in the women with normal cytology or benign alterations, 26,7% in the ones that had atypical squamous cells of undetermined significance (ASC-US) and 80% in those with Low grade squamous intraepithelial lesion (LSIL). the HPV infection prevalence was larger in the patients with up to 30 years of age and in the unmarried women, and those that had more than one sexual partner presented larger infection risk. The results show that the sexual relationship with multiple partners increased the infection risk for HPV and consequently the possibility of the occurrence of lesions uterine cervix