Artículos y presentaciones en Congresos
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Acceso Abierto Tyrosine phosphorylation and morphological transformation induced by four vanadium compounds on MC3T3E1 cells(1999) Salice C., Viviana; Cortizo, Ana María; Gómez Dumm, César; Etcheverry, Susana B.The present study was performed to determine the phosphotyrosine-protein levels induced by insulin and by four vanadium derivatives in MC3T3E1 osteoblast-like cells. We have also attempted to associate these patterns with the vanadium-induced growth and morphological changes of such cells. Vanadate (Vi), vanadyl (VO), bis(maltolato)oxovanadium (IV) (BMOV) and bis(maltolato)dioxovanadium (V) (BMV) stimulate cell growth in a narrow range of concentration, but are also inhibitors for the cells at high concentrations. Vanadium-treated cells displayed clear changes in their morphology after overnight incubation. However, BMV was the least cytotoxic and the weakest inducer of morphological changes. All the compounds promote the phosphorylation of tyrosine residues in several proteins. This effect was more pronounced at low than at high doses. At low doses (10 μM), BMV showed a phosphorylation pattern similar to that of insulin, while Vi, VO and BMOV induced strong phosphorylation of cell proteins. The present findings suggest that the vanadium-induced growth regulation and morphological changes in MC3T3E1 osteoblast-like cells are associated with the ability of these agents to increase the phosphotyrosine protein levels and to inhibit phosphotyrosine phosphatases. These properties are dependent on the oxidation state as well as on the organic ligand which coordinates the vanadium atom. - Artículo
Acceso Abierto Active and pH-Sensitive Nanopackaging Based on Polymeric Anthocyanin/Natural or Organo-Modified Montmorillonite Blends: Characterization and Assessment of Cytotoxicity(2022) Gutiérrez, Tomy J.; León, Ignacio E.; Ponce, Alejandra C.; Álvarez, Vera A.Polymeric anthocyanins are biologically active, pH-sensitive natural compounds and pigments with beneficial functional, pharmacological and therapeutic properties for consumer health. More recently, they have been used for the manufacture of active and pH-sensitive (“intelligent”) food nanopackaging, due to their bathochromic effect. Nevertheless, in order for polymeric anthocyanins to be included either as a functional food or as a pharmacological additive (medicinal food), they inevitably need to be stabilized, as they are highly susceptible to environmental conditions. In this regard, nanopackaging has become a tool to overcome the limitations of polymeric anthocyanins. The objective of this study was to evaluate their structural, thermal, morphological, physicochemical, antioxidant and antimicrobial properties, as well as their responses to pH changes, and the cytotoxicity of blends made from polymeric anthocyanins extracted from Jamaica flowers (Hibiscus sabdariffa) and natural or organo-modified montmorillonite (Mt), as active and pH-sensitive nanopackaging. This study allowed us to conclude that organo-modified Mts are efficient pH-sensitive and antioxidant nanopackaging systems that contain and stabilize polymeric anthocyanins compared to natural Mt nanopackaging and stabilizing polymeric anthocyanins. However, the use of these polymeric anthocyanin-stabilizing organo-modified Mt-based nanopackaging systems are limited for food applications by their toxicity. - Resumen
Acceso Abierto Versatility in the biological behavior of two aminobenzoate oxidovanadium (V, IV) compounds. Inhibition or simulation of enzymes(2018) Parente, Juliana Elena; Naso, Luciana G.; Jori, Khalil; Arndt, Anderson; Franca, Carlos A.; Costa Ferreira, Ana M. da; Bortolin Uliana, Silvia R.; Pannia Espósito, Breno; Williams, Patricia Ana María; Ferrer, Evelina G.The pharmacological potential of vanadium compounds is of great interest to researchers in treatments of various diseases (diabetes, cancer, tropical endemic diseases, etc.). On the basis of the potential biological/pharmacological applications, in this work we have synthesized and physico-chemically characterized, two new complexes containing vanadium (IV) and (V) with 4-aminobenzoic acid as the ligand (L). - Artículo
Acceso Abierto Uncertainty studies of topographical measurements on steel surface corrosion by 3D scanning electron microscopy(2012) Kang, Kyun Won; Pereda, María Dolores; Canafoglia, María Elena; Bilmes, Pablo David; Llorente, Carlos Luis; Bonetto, RitaPitting corrosion is a damage mechanism quite serious and dangerous in both carbon steel boiler tubes for power plants which are vital to most industries and stainless steels for orthopedic human implants whose demand, due to the increase of life expectation and rate of traffic accidents, has sharply increased. Reliable methods to characterize this kind of damage are becoming increasingly necessary, when trying to evaluate the advance of damage and to establish the best procedures for component inspection in order to determine remaining lives and failure mitigation. A study about the uncertainties on the topographies of corrosion pits from 3D SEM images, obtained at low magnifications (where errors are greater) and different stage tilt angles was carried out by using an in-house software previously developed. Additionally, measurements of pit depths on biomaterial surfaces, subjected to two different surface treatments on stainless steels, were carried out. The different depth distributions observed were in agreement with electrochemical measurements. - Artículo
Embargado Potential bio-protective effect of copper compounds: mimicking SOD and peroxidases enzymes and inhibiting acid phosphatase as a target for anti-osteoporotic chemotherapeutics(2018) Martini, Nancy; Parente, Juliana Elena; D'Alessandro, Franco; Rey, Marilin; Rizzi, Alberto; Williams, Patricia Ana María; Ferrer, Evelina G.Copper complexes with transformed methimazole ligand have been synthesized and characterized by elemental analysis, conductivity measurements, thermogravimetric analysis, EPR, FTIR and UV–Vis spectroscopies. Results support their stoichiometries and geometrical structures: [Cu(C4H5N2S)2Cl2]·2H2O(1), [Cu(C8H10N4S)SO4H2O](2) and [Cu(C8H10N4S)SO4](3). ((C4H5N2)2S: bis(l-methylimidazol-2-yl)sulfide; (C4H5N2S)2 = Bis[bis(l-methylimidazol-2-yl)disulfide]) Concurrently, the structurally distinct soluble species corresponding to complexes (1) and (2) were subsequently used in an in vitro investigation of their potential biological properties. In view of their possible pharmaceutical activity, the complexes were in vitro evaluated as phosphatase acid inhibitors. Their radical bio-protective effects were also studied measuring the effect against DPPH• and O2•− radicals. Additional catalytic properties as peroxidase mimics were evaluated using Michaelis–Menten kinetic model by means of phenol red and pyrogallol assays. The complexes exhibited catalytic bromination activity and the ability to oxidize pyrogallol substrate indicating that they can be considered as functional models. The relationships between the structures and the in vitro biological activities have also been considered. Serum protein albumin has attracted the greatest interest as drug carrier and the affinity of biological/pharmaceutical compound is relevant to the development of new medicine. In that sense, interaction studies by fluorescence and EPR spectroscopies were performed showing the binding capacity of the complexes. - Documento de conferencia
Acceso Abierto Sistemas modelos biomiméticos de haloperoxidasas e inhibidores de fosfatasa ácida y alcalina(2017) Parente, Juliana Elena; Jori, Khalil; Naso, Luciana G.; Williams, Patricia Ana María; Ferrer, Evelina G.El objetivo de esta investigación se centra en el estudio de las potencialidades de los complejos de coordinación con vanadio como simuladores de la actividad desarrollada por las enzimas peroxidasas e inhibidores de la actividad de las fosfatasas. - Artículo
Embargado Evidence of promising biological-pharmacological activities of the sertraline-based copper complex: (SerH2)2[CuCl4](Elsevier, 2017) Martini, Nancy; Parente, Juliana Elena; Toledo, María Eugenia; Escudero, Graciela E.; Laino, Carlos; Martínez Medina, Juan José; Echeverría, Gustavo A.; Piro, Oscar E.; Lezama, Luis; Williams, Patricia Ana María; Ferrer, Evelina G.In the current study the ability of copper complex to exert multiple biological activities is combined with the pharmacological action of sertraline (SerH2Cl, antidepressant drug). The hydrated and anhydrous forms of the tetrachlorocuprate(II) salts, namely (SerH2)2[CuCl4]·½H2O and (SerH2)2[CuCl4], were synthesized and characterized by physicochemical methods. The crystal structures were determined by X-ray diffraction methods. The hydrate complex crystallizes in the monoclinic P21 space group with a =8.0807(2) Å, b =36.2781(8) Å, c =12.6576(3) Å, β =95.665(2)°, and Z =4 molecules per unit cell and the un-hydrate in P21 with a =13.8727(6) Å, b =7.5090(3) Å, c= 18.618(1) Å, β =104.563(6)°, and Z =2. It has been suggested that Cu(II) ions might be critical in the development of mood disorders, showed potent biocidal activity, and also acted as analgesic adjuvant. To improve sertraline efficiency, the antidepressant and analgesic activities of the complex have been assessed in rats denoting a marked synergistic effect. Antithyroid and antimicrobial activities were also evaluated. Because depressive disorders and hyperthyroidism diseases led to an oxidative stress state, antioxidant capability has also been tested. The complex behaved as a good superoxide radical scavenger (IC50=6.3 × 10−6 M). The ability of the complex to act as bromoperoxidase mimic was assessed. A pseudofirst order constant of k = 0.157 ± 0.007 min−1 has been determined. The complex evidences promising biological-pharmacological activities and the albumin binding studies showed a Kb of 2.90 ×103 M−1 showing an improvement in the uptake of sertraline by albumin at 8 h incubation (time required for effective interaction of sertraline with the protein). - Artículo
Acceso Abierto Dynamic laser speckle technique as an alternative tool to determine hygroscopic capacity and specific surface area of microporous zeolites(2018) Mojica Sepúlveda, Ruth Dary; Mendoza Herrera, Luis Joaquín; Grumel, Eduardo Emilio; Soria, Delia Beatriz; Cabello, Carmen Inés; Trivi, Marcelo RicardoAdsorption phenomena have several technological applications such as desiccants, catalysts, sep- aration of gases, etc. Their uses depend on the textural properties of the solid adsorbent and the type of the adsorbed liquid or gas. Therefore, it is important to determine these properties. The most common measurement methods are physicochemical based on adsorption of N2 to determine the surface area and the distribution of pores size. However these techniques present certain limi- tations for microporous materials. In this paper we propose the use of the Dynamic Laser Speckle (DLS) technique to measure the hygroscopic capacity of a microporous natural zeolite and their modi ed forms. This new approach based on the adsorption of water by solids allows determine their speci c surface area (S). To test the DLS results, we compared the obtained S values to those calculated by di erent conventional isotherms using the N2 adsorption-desorption method. - Artículo
Acceso Abierto Hydro-Adsorption Study by Dynamic Laser Speckle of Natural Zeolite for Adsorbent and Fertilizer Applications(2016) Mojica Sepúlveda, Ruth Dary; Mendoza Herrera, Luis Joaquín; Agosto, María Florencia; Grumel, Eduardo Emilio; Soria, Delia Beatriz; Cabello, Carmen Inés; Trivi, Marcelo RicardoThe dynamic behavior caused by hydro-adsorption process of materials based on a rich mineral clinoptilolite together with their acidic, basic and calcinated forms has been studied by the dynamic laser speckle (DLS) technique. We propose a modified Peleg’s equation to improve fitting of DLS data. Textural (BET), structural (XRD) and spectroscopic (FTIR) properties were also studied and compared. We demonstrated that DLS was the most sensitive, simple and inexpensive method for comparing the performance of adsorptive materials with slightly modified surfaces. It also allowed the correlation with physicochemical properties. - Artículo
Acceso Abierto Structure-toxicity relationships for aliphatic compounds based on Correlation Weighting of Local Graph Invariants(MDPI (Multidisciplinary Digital Publishing Institute), 2003) Toropov, Andrey A.; Duchowicz, Pablo Román; Castro, Eduardo A.Quantitative Structure-Activity Relationships based on molecular descriptors calculated with Correlation Weights of Local Graph Invariants were developed to model the toxicity of aliphatic compounds to the 50% population growth inhibition. The relationships were computed on the basis of Labeled Hydrogen- Filled Graphs and correlation weights were obtained by an optimization to render as large as possible correlation coefficients between log(IGC 50-1) and descriptors calculated with correlation weights. Morgan extended connectivity indices of zero, first, and second orders, paths of lengths two and three and valence shells of second and third ranges have been tested as local invariants of the Labeled Hydrogen-Filled Graphs. The best quantitative relationship obtained from the optimization of correlation weights is that one based on the valence shell of range two. First, second, and third order fitting equations were determined and statistical results are better than other similar data for the same molecular set. - Artículo
Acceso Abierto Maximum topological distances based indices as molecular descriptors for QSPR. 4. Modeling the enthalpy of formation of hydrocarbons from elements(MDPI (Multidisciplinary Digital Publishing Institute), 2001) Mercader, Andrés; Castro, Eduardo A.; Toropov, Andrey A.The enthalpy of formation of a set of 60 hydroarbons is calculated on the basis of topological descriptors defined from the distance and detour matrices within the realm of the QSAR/QSPR theory. Linear and non-linear polynomials fittings are made and results show the need to resort to higher-order regression equations in order to get better concordances between theoretical results and experimental available data. Besides, topological indices computed from maximum order distances seems to yield rather satisfactory predictions of heats of formation for hydrocarbons. - Artículo
Acceso Abierto Improved molecular descriptors based on the optimization of correlation weights of local graph invariants(MDPI (Multidisciplinary Digital Publishing Institute), 2001) Krenkel, Germán; Castro, Eduardo A.; Toropov, Andrey A.We report the calculation of boiling points for several alkyl alcohols through the use of improved molecular descriptors based on the optimization of correlation weights of local invariants of graphs. As local invariants we have used the presence of different chemical elements (i.e. C, H, and O) and the existence of different vertex degree values (i.e. 1, 2, 3 and 4). The inherent flexibility of the chosen molecular descriptor seems to be rather suitable to obtain satisfactory enough predictions of the property under study. Comparison with other similar approximation reveals a very good behavior of the present method. The use of higher order polynomials do not seem to be necessary to improve results regarding the simple linear fitting equations. Some possible future extensions are pointed out in order to achieve a more definitive conclusion about this approximation. - Artículo
Acceso Abierto Spectroscopic and Microscopic Characterization of Volcanic Ash from Puyehue-(Chile) Eruption: Preliminary Approach for the Application in the Arsenic Removal(Hindawi Publishing Corporation, 2013) Botto, Irma Lía; Canafoglia, María Elena; Gazzoli, Delia; González, María JoséVolcanic ash fromPuyehueCordonCaulleVolcanicComplex (Chile), emitted on June 4, 2011, and deposited inVilla LaAngostura at ∼40 kmof the source, was collected and analyzed by Raman spectroscopy, optical and scanning electron microscopy (SEM-EDS), Xray diffraction (XRD), surface area (BET), and chemical analysis (ICP-AES-MS technique).Themineralogical and physicochemical study revealed that the pyroclastic mixture contains iron oxides in the form of magnetite and hematite as well as pyroxene and plagioclase mineral species and amorphous pumiceous shards. Carbonaceous material was also identified. Physicochemical techniques allow us to select two representative samples (average composition and Fe-rich materials) which were used to analyze their performances in the adsorption process to remove arsenic from water. Additional iron activation by means of ferric salts was performed under original sample. Results showed that the low-cost feedstock exhibited a good adsorption capacity to remove the contaminant, depending on the iron content and the water pH. - Artículo
Acceso Abierto Three new vanadyl(IV) complexes with non-steroidal anti-inflammatory drugs (Ibuprofen, Naproxen and Tolmetin)(2002) Etcheverry, Susana B.; Barrio, D. A.; Cortizo, Ana María; Williams, Patricia Ana MaríaThe synthesis and spectral and magnetic characterization of VO(2+) complexes with Ibuprofen (2-(4-isobutylphenyl)propionic acid), Naproxen (6-methoxy-alpha-methyl-2-naphthalene acetic acid) and Tolmetin (1-methyl-5-(4-methylbenzoyl)-1H-pyrrole-2-acetic acid) were studied. The complexes [VO(Ibu)(2)] x 5CH(3)OH, [VO(Nap)(2)] x 5CH(3)OH and [VO(Tol)(2)] were obtained from methanolic solutions under nitrogen atmosphere. The biological activities of these complexes on the proliferation of two osteoblast-like cells in culture (MC3T3E1 and UMR106) were compared with that of the vanadyl(IV) cation. The complexes exhibited different effects depending on the concentration and the cellular type, while no effect was observed for their parent drugs. - Artículo
Acceso Abierto Synthesis, characterization and bioactivity of a new VO2q/Aspirin complex(2000) Etcheverry, Susana B.; Williams, Patricia Ana María; Barrio, D.A.; Salice C., Viviana; Ferrer, E. G.; Cortizo, Ana MaríaA new VO2q complex with salicylic acid acetate (Aspirin) of formula C18H18Cl2O12V2 was synthesized and characterized. Its biological effects upon cell proliferation, differentiation and promotion of tyrosine protein phosphorylation have been tested in two lines of osteoblastlike cells in culture. - Artículo
Acceso Abierto Biochemical properties and mechanism of action of a vanadyl(IV) – aspirin complex on bone cell lines in culture(2002) Etcheverry, Susana B.; Williams, Patricia Ana María; Sálice, Viviana C.; Barrio, Daniel A.; Ferrer, Evelina G; Cortizo, Ana MaríaA recently synthesized vanadyl(IV) complex with aspirin [VO(aspirin)ClH2O]2, has been thoroughly investigated by physicochemical techniques. In order to support the proposed structure, stoichiometry and the coordination sphere of the vanadium center, some studies such as elemental analysis, electronic (diffuse reflectance) and vibrational (infrared) spectroscopies, magnetic susceptibility, as well as the thermal behavior, were carried out. The bioactivity of the vanadium complex (VOAspi) was evaluated on two osteoblast-like cell lines in culture, being its cytotoxic effects stronger than the vanadyl cation as assessed by morphological changes and lipid peroxidation. These effects may be partially explained through the induction of the expression of Erks (Extracellular signal-regulated kinases) and the inhibition of the PTPases (Phosphotyrosine phosphatases) present in the cellular extracts. - Artículo
Acceso Abierto Interacción del catión VO2+ con suprofen(1998) Kögerler, Paul; Barán, Enrique José; Williams, Patricia Ana MaríaThe interaction of the oxovanadium (IV) cation with the anti inflammatory drug Suprofen has been investigated by means of electronic absorption spectroscopy in solution. The drug binds to the oxocation through its carboxylate group generating a 2:l ligand-to-metal complex. Some comparisons with related compounds are made. - Documento de conferencia
Acceso Abierto Pasantías preuniversitarias en Química: una propuesta para la integración de la escuela media con la universidad(2007) Soria, Delia B.; Naso, Luciana; Salinas, María Victoria; González, Micaela; Ferrer, Evelina G.; Williams, Patricia Ana MaríaObjetivos:\n- Desarrollar un contexto que permita contribuir a la formación de recursos humanos en el campo de las Ciencias Exactas y Naturales.\n- Permitir la participación concreta de alumnos de los últimos años de la Escuela Media.\n- Lograr en los alumnos la integración de los conocimientos así como del fortalecimiento del pensamiento analítico, reflexivo y ético.\n- Lograr en los alumnos que adquieran la habilidad de aplicar criterios para comparar, inferir, deducir, relacionar, establecer semejanzas y diferencias entre aspectos teóricos y las aplicaciones prácticas realizadas.\n- Forjar la construcción de una visión científica del mundo natural. - Documento de conferencia
Acceso Abierto Gases que salvan vidas(2009) Naso, Luciana; Ferrer, Evelina G.; Williams, Patricia Ana MaríaNuestra propuesta se fundamenta en recopilar ideas, ejemplos de la literatura y experiencias sencillas y realizables con materiales de bajo costo y con un eje de motivación-aplicación con la finalidad de proponer actividades y redireccionarlas hacia un aspecto concreto, que en este caso presentamos como gases que salvan vidas . El texto, va acompañado de una introducción teórica (que muchas veces no encontramos) a los conceptos utilizados y a las aplicaciones. La propuesta además tiene como objetivo romper con el mito de que la química se asocia a lo tóxico y contaminante y mostrar cómo se encuentra integrada a nuestra vida cotidiana y nos beneficia diariamente casi sin darnos cuenta. En esta oportunidad trabajamos con los gases de la respiración O2, CO2 y sus aplicaciones.