Classic and New Diagnostic Approaches to Childhood Tuberculosis

Tuberculosis in childhood differs from the adult clinical form and even has been suggested that it is a different disease due to its differential signs. However, prevention, diagnostics, and therapeutic efforts have been biased toward adult clinical care. Sensibility and specificity of new diagnostic approaches as GeneXpert, electronic nose (E-nose), infrared spectroscopy, accelerated mycobacterial growth induced by magnetism, and flow lateral devices in children populations are needed. Adequate and timely assessment of tuberculosis infection in childhood could diminish epidemiological burden because underdiagnosed pediatric patients can evolve to an active state and have the potential to disseminate the etiological agent Mycobacterium tuberculosis, notably increasing this worldwide public health problem

Physicochemical properties of nanosystems stabilized by sodium caseinete: emulsions, gels and films

Las emulsiones de aceite en agua (O/W) son sistemas de gran relevancia industrial encontrando aplicaciones en el área de alimentos, cosméticos y productos farmacéuticos. Estos sistemas consisten en una fase dispersante acuosa y una fase dispersa oleosa, estabilizadas cinéticamente por el agregado de surfactantes. En la industria de alimentos los surfactantes naturales más empleados son diferentes tipos de hidratos de carbono, gomas y proteínas. El caseinato de sodio es una proteína muy usada por su alta capacidad de dispersión y buenas propiedades alimenticias. La estabilidad de las emulsiones es una característica clave para este tipo de aplicaciones. Recientemente se han desarrollado metodologías para la preparación de nanoemulsiones O/W, las cuales se caracterizan por poseer radio medio de gota inferior a los 100 nm. Estos sistemas exhiben nuevas propiedades que resultan interesantes, destacándose su elevada estabilidad, mayor transparencia y menor viscosidad que las emulsiones convencionales. Hasta el momento se han estudiado unas pocas nanoemulsiones O/W con aplicaciones en alimentos y aún no se han descripto sus hidrogeles, aero-geles o películas. En el presente trabajo de tesis se logró preparar nanoemulsiones de caseinato de sodio/aceite de girasol por un método combinado de tres etapas: homogenización a altas revoluciones, ultrasonicación y evaporación de solvente a baja presión. Los radios medios de gota resultaron ser 50±20 nm. Se estudiaron en profundidad, empleando métodos de dispersión de luz, los factores que determinan la estabilidad de la nanoemulsión, así como los mecanismos de desestabilización preponderantes. Se describió la estructura del sistema en la nanoescala, usando técnicas de dispersión de rayos X a bajo ángulo (SAXS). A partir de las nanoemulsiones se prepararon hidrogeles por acidificación homogénea usando la lactona del ácido -glucónico (GDL). Se estudiaron los cambios estructurales producidos en la transición emulsión/gel y el efecto de la sacarosa en la cinética de gelificación y en las propiedades mecánicas de los hidrogeles. Se recurrió a técnicas tales como dispersión de luz, SAXS y reología. Se determinó que los geles preparados a partir de nanoemulsiones poseen módulos de almacenamiento más grandes que los correspondientes geles preparados a partir de emulsiones convencionales debido a que las unidades estructurales son menores. A partir de las mismas nanoemulsiones, por agregado de proporciones adecuadas de un agente plastificante y TiO2 nanoparticulado como refuerzo estructural, se prepararon también películas plásticas por un proceso de gelificación seguido de secado a humedad controlada. Estas películas presentaron excelente homogeneidad, y mayores módulos de Young que las correspondientes a películas preparadas a partir de emulsiones convencionales. Estos sistemas son los primeros en ser informados en la literatura internacional.Oil in water emulsions (O/W) are relevant systems for different industries, in particular for food, cosmetic and pharmacy production. O/W emulsions are precursors for a variety of products produced by the mentioned industries. These systems consist of an oil phase dispersed in an aqueous phase, stabilized by appropriate surfactants and coadjutants. In food industry surfactants must be edibles, being carbohydrates, gums and proteins typically used as stabilizers. Sodium caseinate is widely used due to high dispersion capacity and food quality. Stability of emulsions is the key characteristic for these types of applications. Recently, new methodologies for the preparation of O/W nanoemulsions for food applications were developed. These nanoemulsions have a mean diameter lower than 100 nm, and exhibit interesting properties as high stability, transparency and low viscosity (compared with regular emulsions). At present, only few O/W nanoemulsions applicable to food industry had been studied. The nanoemulsion to nanogel transition and the properties of nanohydrogels and films are even more unknown than the nanoemulsions itself. In this work sodium casinate stabilized nanoemulsions with sunflower oil as lipid phase were prepared by a method that combines three steps: homogeneization at high speed, ultrasound and solvent evaporation at low pressure. This methodology allowed the preparation of nanoemulsions with media radii lower than 50 nm. The factors that affect nanoemulsion stability, and the destabilization mechanisms were studied in depth by light dispersion. The structure of the system at the nanoscale was described with the help of Small Angle X-ray Scattering (SAXS). From nanoemulsions, hydrogels were prepared by homogeneous acidification through the hydrolysis of delta-glucolactone (GDL). The structural changes produced during the nanoemulsion to gel transition, the kinetic of gelification and the mechanical properties of hydrogels were studied by light dispersion, SAXS and rheology. It was determined that the gels produced from nanoemulsions display storage modulus higher than the gels prepared from regular emulsion due to the lower size of building blocks. From nanoemulsions, by incorporation of appropriate amounts of plasticizer and TiO2 nanoparticles (as reinforcement), plastic films were prepared by gelification followed by drying at controlled relative humidity. These films displayed excellent homogeneity and higher Young modulus than the corresponding films prepared from regular emulsions. These systems are the first described in the specialized literature.Fil: Montes De Oca Ávalos, Juan Manuel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Una mirada al envejecimiento activo según las personas mayores y sociedad civil en España y México. Aportes para el diseño de políticas públicas

8º Congreso CEISALN

A modified chemical protocol of decellularization of rat sciatic nerve and its recellularization with mesenchymal differentiated Schwann-Like cells: Morphological and functional assessments

The functional reconstruction of large neural defects usually requires the use of peripheral nerve autografts, though these have certain limitations. As a result, interest in new alternatives for autograft development has risen. The acellular peripheral nerve graft is an alternative for peripheral nerve injury repair, but to date there is not a standardized chemical decellularization method widely accepted. The objective of this study was to propose a modified chemical protocol of decellularization of rat sciatic nerve and its recellularization in vitro with mesenchymal differentiated Schwann-like cells. After the transplantation, an evaluation of its regeneration was performed using morphological and functional tests. The study consisted of two phases; in phase 1, different concentrations and times of exposure of rat sciatic nerves to detergents were tested, to establish a modified chemical protocol for nerve decellularization. The chemical treatment with 3% triton X-100 and 4% sodium deoxycholate for 15 days allowed a complete decellularization whilst conserving the extracellular matrix of the harvested nerve. In phase 2, the decellularized and recellularized alografts were compared against autografts. The morphological analysis showed a higher positivity to specific myelin antibodies in the recellularized group compared to the autograft. There were no differences in this parameter between the control limb and the experimental limb (recellularized group). The functional analysis showed no statistical differences at week 15 in the Sciatic Function Index in the autograft group vs the other groups. This study sets the morphological and functional bases for posterior studies about nerve defects regeneration in humans