Chitosan derivatives as nanocarriers for hLDHA inhibitors delivery to hepatic cells: A selective strategy for targeting primary hyperoxaluria diseases.

Primary hyperoxalurias (PHs) are a group of inherited alterations of the hepatic glyoxylate metabolism that result in an excess of oxalate production by the oxidation of glyoxylate by the human lactate dehydrogenase A enzyme (hLDHA). The selective liver inhibition of this enzyme is one of the therapeutic strategies followed in the treatment of this disease. Even though several efforts have been recently performed using gene silencing by the RNA interference approach, small-molecule inhibitors that selectively reach hepatocytes are preferred since they present the advantages of a lower production cost and better pharmacological properties. In that sense, the design, synthesis, and physicochemical characterization by NMR, FTIR, DLS and TEM of two nanocarriers based on chitosan conjugates (1, non-redox-sensitive; 2, redox-sensitive) have been performed to (i) achieve the selective transport of hLDHA inhibitors into hepatocytes and (ii) their disruption once they reach the hepatocytes cytosol. Polymer 2 self-assembled into micelles in water and showed high drug loadings (19.8-24.5 %) and encapsulation efficiencies (31.9-40.8%) for the hLDHA inhibitors (I-III) tested. The non-redox-sensitive micelle 1 remained stable under different glutathione (GSH) concentrations (10 µM and 10 mM), and just a residual release of the inhibitor encapsulated was observed (less than 10 %). On the other hand, micelle 2 was sufficiently stable under in vitro physiological conditions (10 µM, GSH) but it quickly disassembled under the simulated reducing conditions present inside hepatocytes (10 mM GSH), achieving a 60 % release of the hLDHA inhibitor encapsulated after 24 h, confirming the responsiveness of the developed carrier to the high levels of intracellular GSH.

pH del agua potable que consumen estudiantes del segundo año de la Carrera de Medicina, Universidad Mayor de San Andrés Gestión 2017 / pH of drinking water that second year students of medicine of the Universidad Mayor de San Andres consume term 2017

INTRODUCCIÓN: El pH es una propiedad básica del agua potable y cuyos valores extremos pueden originar reacciones secundarias dañinas, entendiéndose por agua potable aquel que puede ser consumido sin restricción para el consumo humano, OBJETIVO: Determinar el valor del pH de agua potable que consumen los estudiantes de segundo año de la carrera de medicina de la Universidad Mayor de San Andrés (UMSA). MATERIAL Y MÉTODOS: Se analizaron 388 muestras de agua potable del domicilio de estudiantes regulares de segundo año cátedra de bioquímica entre los meses de julio y agosto del 2017, realizándose un estudio de tipo descriptivo con un enfoque transeccional. RESULTADOS: Se obtuvieron los siguientes resultados, 1) la media del pH total fue de 7,24; con x=7,22 en la ciudad de la Paz y x=7,28 en la ciudad de el Alto. 2) en cuanto al sistema de potabilización se obtuvo: x=7,34 en la planta el Alto, x=7,21 en la planta de Tilata, x=7,15 en la planta de Achachicala y de x=7,20 en la planta de Pampahasi. CONCLUSIONES: El pH del agua potable consumida se encontró dentro de parámetros establecidos con un valor medio de 7,24.

INTRODUCTION: The pH is a basic property of potable water and whose extreme values may cause harmful secondary reactions. It is understood that potable water can be consumed without any restriction by human beings. OBJECTIVE: To determine the pH value of potable water consumed by medicine students of second year at UMSA university. MATERIAL AND METHODS: 388 samples of potable water were analyzed which were taken from the homes of the second year students of the biochemistry department between July and August 2017, developing a descriptive study with a cross-sectional approach. RESULTS: The following results were obtained: 1) the average of the pH was 7.24; with x = 7.22 in La Paz city and x = 7.29 in El Alto city. 2) in relation to the drinking water was obtained: x=7.34 in El Alto plant, x=7.21 in Tilata plant, x=7.16 in Achachicala plant and x=7.21 in Pampahasi plant. CONCLUSION: The pH of the drinking water drunk is established within parameters with an average value of 7.24.

Adsorption of quantum dots onto polymer and Gemini surfactant films: a quartz crystal microbalance study.

We used quartz crystal microbalance with dissipation to study the mechanical properties, the kinetics of adsorption, and the amount of CdSe quantum dots (QDs) adsorbed onto a SiO2 sensor, referred as bare sensor, onto the sensor modified with a film of the polymer poly(maleic anhydride-alt-1-octadecene), PMAO, or with a film of the Gemini surfactant ethyl-bis(dimethyl octadecyl ammonium bromide), abbreviated as 18-2-18. Results showed that when the sensor is coated with polymer or surfactant molecules, the coverage increases compared with that obtained for the bare sensor. On the other hand, rheological properties and kinetics of adsorption of QDs are driven by QD nanoparticles. Thus, the QD films present elastic behavior, and the elasticity values are independent of the molecule used as coating and similar to the elasticity value obtained for QDs films on the bare sensor. The QD adsorption is a two-step mechanism in which the fastest process is attributed to the QD adsorption onto the solid substrate and the slowest one is ascribed to rearrangement movements of the nanoparticles adsorbed at the surface.