Susceptibilidad a la corrosión de agregados pétreos para hormigón a partir del estudio sobre superficies pulidas

The susceptibility to corrosión of quartzose sandstone in alkaline médium was study. It is known that it is a highly reactive material when it is used in concrete of portland cement. Corrosión tests were made over polished surfaces to anaiyze the rock damage, reaction velocity and the identity of the corroded minerals. Samples were corroded with a NaOH IN solution at 80 C, and the evolution of reaction was study by means a polarization microscope, which allows to record an image each seven hours in the same section. The results were treated statistically using multivariate analyses over the pixel luminosity of digitalized images. It was performed a covariance matrix from the data matrix and the principal components were calculated. The results were plotted in a 3D graphic where it is possible to notice the relief sampic, which reflects the differential attack in different sectors. The upper dots correspond to quartz grains and the depressed zones to the opaline cement. Later, a map with the isoluminosity curves were made to show reaction zones. The application of this method to different minerals and rocks is proposed with the aims to evalúate preliminary the potentíal reactivity in aggregates used in concrete and to know which are the materials responsable of damage in hardened concrete

Determinación de montmorillonita en rocas basálticas

En el presente trabajo se propone un método colorimétrico para la determinación de montmorillonita en rocas basálticas, que consiste en la tinción de la muestra con azul de metileno. Se trabaja sobre secciones delgadas con microscopio de polarización, donde la montmorillonita aparece coloreada. Se desarrolló un software que permite cuantificar su presencia. Se comprobó su efectividad testeándolo en muestras con contenidos conocidos de montmorillonita. Se trabajó sobre 3 rocas de comportamiento conocido frente a la RAS, estudiadas previamente por los ensayos normalizados convencionales como son: el método acelerado de la barra de mortero, examen petrográfico y método químico.The object of this work is to propose a software developed with the aims to quantify the presence of montmorillonite in basaltic rocks. The method is based in the tinction of the montmorillonite in thin section by means of methylene blue. The effectively of the method has been testes with samples of known quantity of montmorillonita. There have been used 3 samples of known ASR behavior and previously study by conventional standard test like: The accelerated method of the mortar bar; the petrographic method and the chemical method

Development and characterization of benznidazole nano- and microparticles: A new tool for pediatric treatment of Chagas disease?

Benznidazole (BNZ) is the drug of choice for the treatment of Chagas disease in many countries. However, its low water solubility produces low and/or variable oral bioavailability. Thus, the aim of this work was to formulate micro- and nanoparticles based on Eudragit® RS PO and Eudragit® RL PO as a convenient approach to increase the dissolution rate of BNZ. The microparticles were obtained by means of spray-drying process while the nanoparticles were prepared through the nanoprecipitation technique and further freeze-drying. The results indicated that nanoparticles were obtained in 86% yield while microparticles were obtained in 68% yield. In both cases, the encapsulation efficiency of particles was greater than 78% while drug loading capacity was nearly 24% w/w and 18% w/w, after spray-drying and freeze-drying procedures, respectively. Images of scanning electron microscopy showed that the particles obtained by spray-drying and freeze-drying were in the micrometer and nanometer scale, respectively. FT-IR spectra of BNZ-loaded particles obtained by both methods showed characteristic bands of BNZ confirming that part of drug remained on their surface. Thermal analysis revealed that the drug crystallinity after both methods decreased. Physical stability evaluation of the nanoparticles confirmed that Pluronic® F68 was suitable to keep the particles size in a range of 300 nm after 70 days storage at 4 ± 2 °C. In-vitro release studies showed increased dissolution rate of drug from the particles obtained by both methods respect to untreated BNZ. The kinetics of drug release in acid media followed the Higuchi kinetics indicating drug diffusion mechanism from particles.Fil: Seremeta, Katia Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Chaco Austral. Departamento de Ciencias Básicas y Aplicadas; ArgentinaFil: Arrua, Eva Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Okulik, Nora Beatriz. Universidad Nacional del Chaco Austral. Departamento de Ciencias Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Salomon, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Nanocarriers for effective delivery of benznidazole and nifurtimox in the treatment of chagas disease: A review

Neglected tropical diseases (NTDs) constitute a group of infectious diseases prevalent in countries with tropical and subtropical climate that affect the poorest individuals and produce high chronic disability associated with serious problems for the health system and socioeconomic development. Chagas disease or American trypanosomiasis is included on the NTDs list. However, even though this disease affects more than 10 million people, mostly in Latin America, causing the death of over 10,000 people every year, only two drugs are approved for its treatment, benznidazole and nifurtimox. These antiparasitic agents were developed almost half a century ago and present several biopharmaceutical disadvantages such as low aqueous solubility and permeability limiting their bioavailability. In addition, both therapeutic agents are available only as tablets and a liquid pediatric formulation is still lacking. Therefore, novel pharmaceutical strategies to optimize the pharmacotherapy of Chagas disease are urgently required. In this regard, nanotechnological approaches may be a crucial alternative for the delivery of both drugs ensuring an effective pharmacotherapy although the successful bench-to-bedside translation remains a major challenge. The present work reviews in detail the formulation and in-vitro/in-vivo analysis of different nanoformulations of nifurtimox and benznidazole in order to enhance their solubility, dissolution, bioavailability and trypanocidal activity.Fil: Arrua, Eva Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Farmacia; ArgentinaFil: Seremeta, Katia Pamela. Universidad Nacional del Chaco Austral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Bedogni, Giselle Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Farmacia; ArgentinaFil: Okulik, Nora Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Chaco Austral; ArgentinaFil: Salomon, Claudio Javier. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Evaluation of New Formulations of Antihelmintic Drugs for the Treatment of Schistosomiasis

La esquistosomosis es una enfermedad causada por parásitos trematodos del género Schistosoma. Afecta principalmente a áreas tropicales y subtropicales, siendo un principal problema de salud mundial por su alta incidencia en estas regiones. Una de las especies de mayor importancia, por su prevalencia y gravedad, es la causada por Schistosoma mansoni,responsable de la esquistosomosis intestinal. El tratamiento de elección esel praziquantel, con altas tasas de eficacia clínica. Sin embargo, el fármacono impide la reinfección y se ha observado fallos terapéuticos en zonasendémicas. Por ello, se hace necesaria la búsqueda de alternativas terapéuticas.El objetivo de este estudio es evaluar dos tipos de formulaciones denanopartículas de praziquantel (tipo A y tipo S) y un tratamiento alternativocomo la ivermectina mediante ensayos in vitro sobre adultos de S. mansoni.Los resultados demostraron que el tratamiento con nanopartículas presentauna eficacia similar o mayor que el empleo de praziquantel comercial. Sinembargo, el tratamiento con ivermectina no aportó evidencias de mayoreficacia. Trabajos futuros irán encaminados a evaluar estas formulacionesen otras fases del ciclo biológico, así como a realizar estudios in vivo enanimales de experimentación.Palabras clave: Schistosoma; esquistosomosis; praziquantel; nanopartículas;ivermectina.Fil: Castrillejo, Sergio A.. Universidad de Salamanca; EspañaFil: López Abán, Julio. Universidad de Salamanca; EspañaFil: Muro, Antonio. Universidad de Salamanca; EspañaFil: Salomon, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Pastor Navarro, Marta. Universidad del País Vasco; España. Centro de Investigación Biomédica en Red; EspañaFil: Pedraz, José Luis. Universidad del País Vasco; España. Centro de Investigación Biomédica en Red; Españ

Effect of drug incorporation technique and polymer combination on the performance of biopolymeric antifungal buccal films

Numerous films with a dissolved or dispersed active principle within a polymeric matrix have been described in literature. However, the incorporation of solid crystals into the films may influence several relevant properties. Additionally, it has been reported that different polymeric matrices lead to films presenting a different performance. The aim of this work was to evaluate the effect of the combination of chitosan with carrageenan (κ-, λ-, and ι-) as matrices, and of the miconazole nitrate incorporation method, on the films behavior. Mechanical properties, drug release and antifungal activity were evaluated. The state of the drug in the films was analyzed by different techniques. Films showed a homogeneous surface and a thermal protective effect on the drug. The combination of chitosan and λ-carrageenan leads to films with the highest values of tensile and mucoadhesive strength. Films with solubilized drug displayed slightly higher elongation at break, tensile and mucoadhesive strength and faster drug release than those with suspended miconazole nitrate. However, no differences were found regarding the antifungal activity of the different formulations including time-to-kill curves.Fil: Tejada Jacob, Guillermo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Lamas, Maria Celina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Svetaz, Laura Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Salomon, Claudio Javier. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alvarez, Vera Alejandra. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Promising Efficacy of Benznidazole Nanoparticles in Acute Trypanosoma cruzi Murine Model: In-Vitro and In-Vivo Studies

The aim of this study was to evaluate the effectiveness of benznidazole nanoparticles (BNZ-nps) on trypomastigote forms and on intracellular infection in mammalian cells and primary cardiac myocyte cells. Its effectiveness was also evaluated on acute Trypanosoma cruzi Nicaragua mice infection. Trypomastigotes from culture were treated with different concentrations of BNZ-nps to determine the drug concentration that lyses 50% of trypomastigotes (LC50). Infected mammalian cells were incubated with different concentrations of BNZ-nps to determine the percentage of amastigote inhibition. C3H/HeN mice with lethal acute infection were treated with 10, 25, and 50 mg/kg/day of BNZ-nps for 30 and 15 days to control the survival rate of animals. BNZ-nps having a mean particle size of 63.3 nm, a size distribution of 3.35, and a zeta potential of -18.30 were successfully prepared using poloxamer 188 as a stabilizer. BNZ-nps 25 and 50 μg/mL showed no significant differences in the percentage of inhibition of infected mammalian cells. Infected mice treated with BNZ-nps (50, 25, and 10 mg/kg/day) for 30 days and with BNZ-nps (50 and 25 mg/kg/day) for 15 days presented a 100% survival, whereas the animals treated with 10 mg/kg/day for 15 days of BNZ-nps showed a 70% survival rate. The results obtained demonstrate, for the first time, that benznidazole nanoparticles are a useful and attractive approach to treat Chagas disease in infected mice.Fil: Scalise, Maria Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Arrua, Eva Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Rial, Marcela Silvina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Salomon, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmaceuticas. Departamento de Farmacia; ArgentinaFil: Fichera, Laura Edith. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; Argentin

Recent advances in the treatment of Chagas disease

Descoberta há cem anos, a doença de Chagas afeta a mais de quinze milhões de pessoas em toda a América Latina e, ainda hoje, não há tratamentoeficaz. O fármaco benznidazol, utilizado como única opção de tratamento no Brasil, é ineficaz na fase crônica da doença. Problemas relacionados à biodisponibilidade do medicamento comercial limitam sua eficácia, principalmente na fase crônica, quando os parasitos estão confinados em tecidos profundos e em lenta replicação. Nesse contexto, pesquisas lideradas por grupos brasileiros e argentinos vêm sendo conduzidas com o objetivo de desenvolver formulações de benznidazol mais eficientes. Diversas formas farmacêuticas sólidas e líquidas foram propostas nos últimos anos com resultados pré-clínicos promissores, sendo descritas melhorias acentuadas nas características farmacocinéticas desse fármaco. Espera-se que as formas inovadoras apresentadas possam ser avaliadas em ensaios clínicos e incorporadas à produção industrial em breve.Discovered about a hundred years ago, Chagas disease currently affects more than fifteen million people in Latin America, and it still remains without any effective treatment. Although benznidazole has been used as the only pharmacotherapeutic option to treat Chagas disease in Brazil, it is ineffective in the chronic phase of the disease, when the parasites are confined to deep tissue layers and slowly replicate. This happens mainly due to problems related to the bioavailability of the drug, which is currently in the market. In this context, Brazilian and Argentinean research groups have conducted studies to develop more efficient benznidazole formulations. Several solid and liquid formulations have been proposed over the last few years with promising preclinical results. Improvements in the pharmacokinetic properties of this drug have been described. Therefore, it is expected, that such innovative drugs and formulations be assessed in clinical trials and soon incorporated to industrial production.Fil: da Cunha Filho, Marcílio Sérgio Soares . Universidade Do Brasilia; BrasilFil: de Sá-Barreto, Lívia Cristina lira . Universidade Do Brasilia; BrasilFil: Leonardi, Darío. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Lamas, Maria Celina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Salomon, Claudio Javier. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; Argentin

High LDL levels are associated with increased lipoprotein-associated phospholipase A(2) activity on nitric oxide synthesis and reactive oxygen species formation in human endothelial cells

Objective: To evaluate in vitro the effects of serum and LDL fractions isolated from hypercholesterolemic patients on nitric oxide (NO) synthesis and reactive oxygen species (ROS) production by human umbilical vein endothelial cells (HUVECs). Design and methods: Serum and LDL isolated from subjects with high (n=18) and normal (n=21) LDL-cholesterol levels were analyzed on NO synthesis and ROS production in vitro models of HUVECs. LDL was furthers characterized in their chemical composition and activities of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), cholesteryl ester transfer protein (CETP) and paraoxonase. Results: NO bioavailability was significantly lower and ROS production higher in HUVECs incubated with serum samples from patients with high LDL-cholesterol levels in comparison to control subjects. Moreover, hypercholesterolemic patients presented higher CETP and Lp-PLA(2) activities than control subjects. LDL fractions isolated from patients and controls were not different in their chemical composition, Lp-PLA(2) activity, and their capacity to reduce NO synthesis and increase ROS production. Conclusion: Alterations of serum from hypercholesterolemic patients could be due to the increment in LDL concentration, main Lp-PLA(2) carrier, and not to LDL composition or intrinsic Lp-PLA(2) activity