Caracterización clínica de leishmaniasis cutánea clásica en niños menores de 5 años del municipio de San José de Bocay, 2003

Tesis (Doctor en Medicina y Cirugía)--Universidad Americana, Managua, 2005Esta investigación define las características de la enfermedad por Leishmaniasis Cutánea Clásica en pacientes menores de 5 años de edad, en el municipio de San José de Bocay en el año 2003, no sólo a causa del incremento en el número de casos, sino también en especial por el impacto socio-económico y psicológico, característico de esta enfermedad frecuentemente debilitante y mutilante, pues el tener mayor conocimiento de este perfil patológico es una prioridad para el Programa Nacional de Leishmaniasis

The shade avoidance syndrome in Arabidopsis : the antagonistic role of phytochrome A and B differentiates vegetation proximity and canopy shade

Light limitation caused by dense vegetation is one of the greatest threats to plant survival in natural environments. Plants detect such neighboring vegetation as a reduction in the red to far-red ratio (R:FR) of the incoming light. The low R:FR signal, perceived by phytochromes, initiates a set of responses collectively known as the shade avoidance syndrome, intended to reduce the degree of current or future shade from neighbors by overtopping such competitors or inducing flowering to ensure seed production. At the seedling stage these responses include increased hypocotyl elongation. We have systematically analyzed the Arabidopsis seedling response and the contribution of phyA and phyB to perception of decreased R:FR, at three different levels of photosynthetically active radiation. Our results show that the shade avoidance syndrome, induced by phyB deactivation, is gradually antagonized by phyA, operating through the so-called FR-High Irradiance Response, in response to high FR levels in a range that simulates plant canopy shade. The data indicate that the R:FR signal distinguishes between the presence of proximal, but non-shading, neighbors and direct foliar shade, via a intrafamily photosensory attenuation mechanism that acts to suppress excessive reversion toward skotomorphogenic development under prolonged direct vegetation shade

Unusual sauropod tracks in the Jurassic-Cretaceous interval of the Cameros Basin (Burgos, Spain)

The Las Sereas site includes at least 14 ichnological outcrops along 5.6 km, in the Lara area, southwest Burgos Province. 67 ichnites of dinosaurs are documented at Las Sereas 7, identified as theropod and sauropod trackways occurring in shallow carbonates of lacustrine environment. Sauropod trackways have intermediate-gauge and low heteropody, and show different anatomical features to other tracks found in the ichnological record, especially in the disposition and orientation of pes digits. They are similar to Polyonyx from the Middle Jurassic of Portugal. However, since they do not preserve reliable manus data they are classified as aff. Polyonyx. The three sauropod trackways are related to the same kind of trackmaker. They differ from each other only in size, and gregarious behavior has not been detected. Analysis of these trackways reveals changes in travel direction even when there are few tracks in each sequence. At the Las Sereas 7 tracksite, the pace length (PL), width of the angulation pattern (WAP) and the WAP/PL ratio and depth analysis via photogrammetry show a direction change in two sauropod trackways. This tracksite and that at La Pedraja are unique in the Tithonian-Berriasian interval of the Iberian Peninsula that occur in a lacustrine environment, and could be indicate of the relationship between the diversity of Iberian, Tithonian-Berriasian sauropod tracks and sedimentary environments.El yacimiento de Las Sereas se compone de al menos 14 afloramientos icníticos que se localizan a lo largo de 5,6 Km de longitud en la comarca de Lara, en el sureste de la provincia de Burgos. En el afloramiento de Las Sereas 7 se han documentado 67 icnitas de dinosaurios, identificadas como terópodas y saurópodas, producidas en un ambiente lacustre carbonatado somero. Las rastros saurópodos son de anchura intermedia y heteropodia baja mostrando caracteres anatómicos diferentes a los encontrados en el registro icnológico conocido, en especial en lo referente a la disposición y orientación de los dedos del pie. La mayor semejanza de estas icnitas saurópodas se establece con Polyonyx del Jurásico Medio de Portugal, pero al carecer de datos fiables sobre la anatomía de las manos en Las Sereas, clasificamos estas icnitas de Burgos como aff. Polyonyx. Los tres rastros saurópodos de Burgos se atribuyen a un mismo icnopoyeta, diferenciándose entre sí sólo por el tamaño, y sin que se haya detectado un comportamiento gregario. En el estudio de estos rastros pueden recogerse datos que informen sobre trayectos con cambio de dirección, incluso cuando lo que se conserva es una serie relativamente corta de pasos. En Las Sereas 7 la combinación de los valores de varios parámetros - longitud de paso (PL), pauta de anchura de angulación (WAP) y relación WAP/PL - y el estudio de la profundidad de las icnitas por fotogrametría permiten interpretar un cambio de dirección en dos de los rastros saurópodos. Este yacimiento y el de La Pedraja son los únicos conocidos en el registro del intervalo Titoniense-Berriasiense de la Península Ibérica que se formaron en un medio lagunar. En este sentido, podría haber una relación entre la diversidad de icnitas saurópodas ibéricas del intervalo Titoniense-Berriasiense y la presencia de éstas en distintos medios sedimentarios

Stress Corrosion Cracking of X70 Pipeline Steel immersed in Synthetic Soil solution

A study of stress corrosion cracking (SCC) susceptibility of API X70 pipeline steel exposed to a synthetics oil solution at room temperature and atmospheric pressure through slow strain rate tests (SSRT) was carried out. Electrochemical noise (EN) measurements were recorded during SSRT in order to studythe SCC process. Additionally, polarization curves (PC) to evaluate the corrosion were carried out. Characteristic current transients were identified and assigned to different processes. EN measurements were analyzed in the time and frequency domain. The current stransients and localization index (LI) indicate that at the beginning of the test, in the elastic and yielding strength zone, the corrosion is dominant by not much transients with low amplitude and frequency. At the maximum strength (UTS) and before fracture, the presence of transients increased. The highest corrosion rate, obtained by Rn and Zn, were obtained in the plastic zone before of the facture. A superficial analysis obtained by scanning electron microscopy (SEM) was carried out on surface of the samples and it revealed the presence of some micro-cracking in the gage section of SSRT specimens. According to SCC index and SEM observations the X70 steel has low SCC susceptibility at the conditions studied

Study of Cellular Processes in Higher Eukaryotes Using the Yeast Schizosaccharomyces pombe as a Model

Schizosaccharomyces pombe (Sz. pombe), or fission yeast, is an ascomycete unicellular fungus that has been used as a model system for studying diverse biological processes of higher eukaryotic cells, such as the cell cycle and the maintenance of cell shape, apoptosis, and ageing. Sz. pombe is a rod-shaped cell that grows by apical extension; it divides along the long axis by medial fission and septation. The fission yeast has a doubling time of 2–4 hours, it is easy and inexpensive to grow in simple culture conditions, and can be maintained in the haploid or the diploid state. Sz. pombe can be genetically manipulated using methods such as mutagenesis or gene disruption by homologous recombination. Fission yeast was defined as a micro-mammal because it shares many molecular, genetic, and biochemical features with cells of higher eukaryotes in mRNA splicing, post-translational modifications as N-glycosylation protein, cell-cycle regulation, nutrient-sensing pathways as the target of rapamycin (TOR) network, cAMP-PKA pathway, and autophagy. This chapter uses Sz. pombe as a useful model for studying important cellular processes that support life such as autophagy, apoptosis, and the ageing process. Therefore, the molecular analysis of these processes in fission yeast has the potential to generate new knowledge that could be applied to higher eukaryotes

Thy-1 (CD90)-Induced Metastatic Cancer Cell Migration and Invasion Are β3 Integrin-Dependent and Involve a Ca²⁺/P2X7 Receptor Signaling Axis.

Cancer cell adhesion to the vascular endothelium is an important step in tumor metastasis. Thy-1 (CD90), a cell adhesion molecule expressed in activated endothelial cells, has been implicated in melanoma metastasis by binding to integrins present in cancer cells. However, the signaling pathway(s) triggered by this Thy-1-Integrin interaction in cancer cells remains to be defined. Our previously reported data indicate that Ca <sup>2+</sup> -dependent hemichannel opening, as well as the P2X7 receptor, are key players in Thy-1-α <sub>V</sub> β <sub>3</sub> Integrin-induced migration of reactive astrocytes. Thus, we investigated whether this signaling pathway is activated in MDA-MB-231 breast cancer cells and in B16F10 melanoma cells when stimulated with Thy-1. In both cancer cell types, Thy-1 induced a rapid increase in intracellular Ca <sup>2+</sup> , ATP release, as well as cell migration and invasion. Connexin and Pannexin inhibitors decreased cell migration, implicating a requirement for hemichannel opening in Thy-1-induced cell migration. In addition, cell migration and invasion were precluded when the P2X7 receptor was pharmacologically blocked. Moreover, the ability of breast cancer and melanoma cells to transmigrate through an activated endothelial monolayer was significantly decreased when the β <sub>3</sub> Integrin was silenced in these cancer cells. Importantly, melanoma cells with silenced β <sub>3</sub> Integrin were unable to metastasize to the lung in a preclinical mouse model. Thus, our results suggest that the Ca <sup>2+</sup> /hemichannel/ATP/P2X7 receptor-signaling axis triggered by the Thy-1-α <sub>V</sub> β <sub>3</sub> Integrin interaction is important for cancer cell migration, invasion and transvasation. These findings open up the possibility of therapeutically targeting the Thy-1-Integrin signaling pathway to prevent metastasis

MgO-mediated activation of active carbon as an affordable strategy to “in situ” degradation of lindane in contaminated soils

The accumulation in soil landfills of toxic and persistent lindane, widely used as an insecticide, triggers the risk of leaching with the concomitant contamination of surrounding rivers. Thus, viable remediation to eliminate in situ high concentrations of lindane in soil and water becomes an urgent demand. In this line, a simple and costeffective composite is proposed, including the use of industrial wastes. It includes reductive and non-reductive base-catalyzed strategies to remove lindane in the media. A mixture of magnesium oxide (MgO) and activated carbon (AC) was selected for that purpose. The use of MgO provides a basic pH. In addition, the specific selected MgO forms double-layered hydroxides in water which permits the total adsorption of the main heavy metals in contaminated soils. AC provides adsorption microsites to hold the lindane and a reductive atmosphere that was increased when combined with the MgO. These properties trigger highly efficient remediation of the composite. It permits a complete elimination of lindane in the solution. In soils doped with lindane and heavy metals, it produces a rapid, complete, and stable elimination of lindane and immobilization of the metals. Finally, the composite tested in lindane-highly contaminated soils permits the “in situ” degradation of nearly 70% of the initial lindane. The proposed strategy opens a promising way to face this environmental issue with a simple, costeffective composite to degrade lindane and fix heavy metals in contaminated soils

Mannose-binding lectin deficiency with eosinophilic meningoencephalitis due to Angiostrongylus cantonensis in children: a case series

<p>Abstract</p> <p>Introduction</p> <p>Eosinophilic meningitis, a potentially fatal disease caused by <it>Angiostrongylus cantonensis</it>, is considered an emerging infectious disease.</p> <p>Case presentation</p> <p>Three Caucasian boys (aged five-years-old, 10-years-old and six-years-old) with a diagnosis of eosinophilic meningoencephalitis caused by <it>Angiostrongylus cantonensis </it>were studied. Serum immunoglobulin A (IgA), IgM, IgG, and complements C3c and C4 levels were quantified by using an immunodiffusion technique. Immunoglobulin E in serum was quantified by nephelometry and mannose-binding lectin by time-resolved fluorometry. Mannose-binding lectin deficiency was observed in the three patients. The first patient showed a reduction in the levels of IgA and IgM and an increase in the values of IgE and C4. The second patient showed a reduction in mannose-binding lectin level with increased IgG, C4 and IgE levels, and the third patient showed a decrease in mannose-binding lectin level and increased levels of IgM and complement C3c as well as a low level of C4.</p> <p>Conclusions</p> <p>To the best of our knowledge, this is the first report of mannose-binding lectin deficiency associated with <it>Angiostrongylus cantonensis </it>meningoencephalitis in children, and it may contribute to the understanding of the participation of this component of the lectin pathway in the development of the disease.</p

Long-range pollution transport during the MILAGRO-2006 campaign: a case study of a major Mexico City outflow event using free-floating altitude-controlled balloons

One of the major objectives of the Megacities Initiative: Local And Global Research Observations (MILAGRO-2006) campaign was to investigate the long-range transport of polluted Mexico City Metropolitan Area (MCMA) outflow and determine its downwind impacts on air quality and climate. Six research aircraft, including the National Center for Atmospheric Research (NCAR) C-130, made extensive chemical, aerosol, and radiation measurements above MCMA and more than 1000 km downwind in order to characterize the evolution of the outflow as it aged and dispersed over the Mesa Alta, Sierra Madre Oriental, Coastal Plain, and Gulf of Mexico. As part of this effort, free-floating Controlled-Meteorological (CMET) balloons, commanded to change altitude via satellite, made repeated profile measurements of winds and state variables within the advecting outflow. In this paper, we present an analysis of the data from two CMET balloons that were launched near Mexico City on the afternoon of 18 March 2006 and floated downwind with the MCMA pollution for nearly 30 h. The repeating profile measurements show the evolving structure of the outflow in considerable detail: its stability and stratification, interaction with other air masses, mixing episodes, and dispersion into the regional background. Air parcel trajectories, computed directly from the balloon wind profiles, show three transport pathways on 18–19 March: (a) high-altitude advection of the top of the MCMA mixed layer, (b) mid-level outflow over the Sierra Madre Oriental followed by decoupling and isolated transport over the Gulf of Mexico, and (c) low-level outflow with entrainment into a cleaner northwesterly jet above the Coastal Plain. The C-130 aircraft intercepted the balloon-based trajectories three times on 19 March, once along each of these pathways; in all three cases, peaks in urban tracer concentrations and LIDAR backscatter are consistent with MCMA pollution. In comparison with the transport models used in the campaign, the balloon-based trajectories appear to shear the outflow far more uniformly and decouple it from the surface, thus forming a thin but expansive polluted layer over the Gulf of Mexico that is well aligned with the aircraft observations. These results provide critical context for the extensive aircraft measurements made during the 18–19 March MCMA outflow event and may have broader implications for modelling and understanding long-range transport

Copper: Synthesis Techniques in Nanoscale and Powerful Application as an Antimicrobial Agent

Nanosized metal particles show specific physical and chemical properties that allow the creation of new composites materials, which are important for multiple applications in biology and medicine such as infections control. Metal nanoparticles, mainly copper, exhibit excellent inhibitory effect on Gram-positive and Gram-negative bacteria; therefore the exploration about the efficient, economical, and friendly environmental technics to synthesize inorganic nanoparticles is imperative. In this work a brief overview of the several methods is made including the comparison of the methods, mainly between sonochemical, microwave, and chemical routes. It allows determining the optimal parameters and technical conditions to synthesize copper nanoparticles with physical and chemical properties suitable for the oral bacterial inhibition