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Jump events in a 3D Edwards-Anderson spin glass
Mártin, Daniel Alejandro; Iguain, Jose Luis
The statistical properties of infrequent particle displacements, greater than a certain distance, are known as jump dynamics in the context of structural glass formers. We generalize the concept of a jump to the case of a spin glass, by dividing the system into small boxes, and considering the infrequent cooperative spin flips in each box. Jumps defined this way share similarities with jumps in structural glasses. We perform numerical simulations for the 3D Edwards-Anderson model, and study how the properties of these jumps depend on the waiting time after a quench. Similar to the results for structural glasses, we find that while jump frequency depends strongly on time, the jump duration and jump length are roughly stationary. At odds with some results reported on studies of structural glass formers, at long enough times, the rest time between jumps varies as the inverse of jump frequency. We give a possible explanation for this discrepancy. We also find that our results are qualitatively reproduced by a fully-connected trap model.
Twisting Hopf algebras from cocycle deformations
Twisting Hopf algebras from cocycle deformations
Andruskiewitsch, Nicolas; Garcia Iglesias, Agustin
Let H be a Hopf algebra. Any finite-dimensional lifting of V∈HHYD arising as a cocycle deformation of A= B(V) # H defines a twist in the Hopf algebra A∗, via dualization. We follow this recipe to write down explicit examples and show that it extends known techniques for defining twists. We also contribute with a detailed survey about twists in braided categories.
Hecke and sturm bounds for Hilbert modular forms over real quadratic fields
Hecke and sturm bounds for Hilbert modular forms over real quadratic fields
Burgos Gil, Jose Ignacio; Pacetti, Ariel Martín
Let K be a real quadratic field and OK its ring of integers. Let Γ be a congruence subgroup of SL2(OK) and M(k1,k2)(Γ) be the finite dimensional space of Hilbert modular forms of weight (k1, k2) for Γ. Given a form f(z) ∈ M(k1,k2)(Γ), how many Fourier coefficients determine it uniquely in such space? This problem was solved by Hecke for classical forms, and Sturm proved its analogue for congruences modulo a prime ideal. The present article solves the same problem for Hilbert modular forms over K. We construct a finite set of indices (which depends on the cusps desingularization of the modular surface attached to Γ) such that the Fourier coefficients of any form in such set determines it uniquely.
Detection of myocardial infarction using delayed enhancement dualenergy CT in stable patients
Detection of myocardial infarction using delayed enhancement dualenergy CT in stable patients
Rodriguez Granillo, Gaston Alfredo; Campisi, Roxana; Deviggiano, Alejandro; de Munain, Maria N. Lopez; De Zan, Macarena; Capunay, Carlos; Carrascosa, Patricia
OBJECTIVE. The objective of our study was to explore whether delayed enhancement dual-energy CT (DECT) allows the detection of myocardial infarcts in stable patients. SUBJECTS AND METHODS. Patients with known or suspected coronary artery disease clinically referred for myocardial perfusion imaging using SPECT were prospectively included. All patients (n = 34) also underwent stress, rest, and delayed enhancement DECT on a DECT scanner. At SPECT, segments with myocardial infarction (MI) were defned as those with a summed rest score of = 2 in two or more consecutive segments, and a diagnosis of MI was supported by wall motion abnormalities, clinical history, and ECG fndings. RESULTS. Segments with MI were identifed in 13 (38%), 15 (44%), and 14 (41%) patients using SPECT, perfusion CT, and delayed enhancement DECT, respectively. When combined SPECT and perfusion CT results were used as the reference standard, delayed enhancement DECT had a sensitivity, specifcity, positive predictive value, and negative predictive value for the detection of MI of 91.7% (95% CI, 62-98%), 86.4% (95% CI, 65-97%), 78.6% (95% CI, 49-95%), and 95.0% (95% CI, 75-100%). At delayed enhancement DECT (40 keV), a signal attenuation higher than 161 HU had a sensitivity of 72% and a specifcity of 79% for the detection of MI on a per-segment basis. The median signal attenuation of myocardial infarcts at 40 keV was 3.0 SDs (interquartile range, 1.3-4.0 SDs) above that of normal myocardium. CONCLUSION. In this study, delayed enhancement DECT allowed the detection of myocardial infarcts in stable patients.
Therapeutic blockade of Foxp3 in experimental breast cancer models
Therapeutic blockade of Foxp3 in experimental breast cancer models
Moreno Ayala, Mariela Alejandra; Gottardo, María Florencia; Imsen, Mercedes; Asad, Antonela Sofía; Bal, Elisa Dora; Casares, Noelia; Lasarte, Juan José; Seilicovich, Adriana; Candolfi, Marianela
Purpose: Regulatory T cells (Tregs) impair the clinical benefit of cancer immunotherapy. To optimize the antitumor efficacy of therapeutic dendritic cell (DC) vaccines, we aimed to inhibit Foxp3, a transcription factor required for Treg function. Methods: Mice bearing established syngeneic LM3 and 4T1 breast tumors were treated with antitumor DC vaccines and a synthetic peptide (P60) that has been shown to inhibit Foxp3. Results: Treatment with P60 improved the therapeutic efficacy of DC vaccines in these experimental models. In addition, monotherapy with P60 inhibited tumor growth in immunocompetent as well as in immuno-compromised animals bearing established tumors. We found expression of Foxp3 in human and murine breast tumor cells. P60 inhibited IL-10 secretion in breast cancer cells that expressed Foxp3. Conclusions: Our results suggest that Foxp3 blockade improves the therapeutic efficacy of DC vaccines by inhibition of Tregs and through a direct antitumor effect. This strategy could prove useful to neutralize the immunosuppressive microenvironment and to boost antitumor immunity in breast cancer.
Los rankings globales de universidades y su función disciplinaria
Los rankings globales de universidades y su función disciplinaria; The global rankings of universities and their disciplinary function
Crisci, Jorge Victor; Apodaca, María José
En la última década los rankings de universidades se han transformado en una fuerza importante con gran influencia en las políticas universitarias locales y globales. Mientras que en algunos países se han llevado a cabo rankings nacionales desde el siglo pasado, los rankings globales de universidades son un fenómeno reciente que tomó fuerza a principios del siglo XXI. Los rankings son vistos como una forma cuantitativa de dar cuenta de responsabilidades y obligaciones institucionales, y la transparencia y calidad de la administración. Hoy día existen, al menos, diez rankings globales de universidades, los cuatro más conocidos son: Academic Ranking of World Universities, SCImago Institutions Rankings, QS World University Rankings, y World University Ranking. Las metodologías de estos rankings son sumariamente presentadas y se discute qué miden y qué no miden. Dos de los más importantes indicadores de todos los rankings (el prestigio y el uso de índices de citas como medida de la calidad de la producción científica) son discutidos críticamente. Se aplica el concepto de disciplina de Foucault para comprender cómo los rankings implícitamente favorecen un cierto modelo de organización de estudios superiores.; Over the last decade, rankings of universities have become a significant force impacting on and influencing higher education policy. While rankings have been part of some national academic system for many years, global rankings are a XXI century phenomenon. Rankings are viewed as a way to demonstrate accountability by formal, quantitative measures. Today there are, at least, ten major global rankings of universities. The most well-known are: Academic Ranking of World Universities, SCImago Institutions Rankings, QS World University Rankings, and World University Ranking. The methodologies of these rankings are briefly presented. What global rankings do measure and what they do not measure is discussed. Two of the most important indicators of rankings (reputation and the use of citation-base indicators for research evaluation) are critically discussed. The application of Foucault´s concept of discipline to rankings, helps to understand how rankings implicitly apply pressure on universities in favor of a specific model of higher education organization.
An Asymmetric Multi-Item Auction with Quantity Discounts Applied to Internet Service Procurement in Buenos Aires Public Schools
An Asymmetric Multi-Item Auction with Quantity Discounts Applied to Internet Service Procurement in Buenos Aires Public Schools
Bonomo, Flavia; Catalán, Jaime; Duran, Ricardo Guillermo; Epstein, Rafael; Guajardo, Mario; Jawtuschenko, Alexis Boris; Marenco, Javier Leonardo
This article studies a multi-item auction characterized by asymmetricbidders and quantity discounts. We report a practical application of thistype of auction in the procurement of Internet services to the 709 publicschools of Buenos Aires. The asymmetry in this application is due to firms?existing technology infrastructures, which affect their ability to providethe service in certain areas of the city. A single round first-price sealed-bidauction, it required each participating firm to bid a supply curve specifyinga price on predetermined graduated quantity intervals and to identify theindividual schools it would supply. The maximal intersections of the setsof schools each participant has bid on define regions we call competitionunits. A single unit price must be quoted for all schools supplied withinthe same quantity interval, so that firms cannot bid a high price wherecompetition is weak and a lower one where it is strong. Quantity discountsare allowed so that the bids can reflect returns-to-scale of the suppliers andthe auctioneer may benefit of awarding bundles of units instead of separateunits. The winner determination problem in this auction poses a challengeto the auctioneer. We present an exponential formulation and a polynomialformulation for this problem, both based on integer linear programming.The polynomial formulation proves to find the optimal set of bids in amatter of seconds. Results of the real-world implementation are reported.
Does Echinoderm research deserve an ethical consideration?
Does Echinoderm research deserve an ethical consideration?
Rubilar Panasiuk, Cynthia Tamara; Crespi Abril, Augusto Cesar
Traditional ethics reflection centers the discussion in conflicts that affect humans. According toepistemology-based ethics, facts are needed to include other living beings as object of ethical consideration. Inthis sense, huge efforts have been made to demonstrate that animal suffering is real. However, the ethical reflectiononly reaches large vertebrates and some species of small ones, excluding invertebrates. However, a differentapproach (ethic-based epistemology) is equally valid and questions the assumptions of traditional ethics. Thisnew insight does not demand facts to demonstrate that living beings should be considered ethically, since ethicsshould be first than epistemology (facts). Thus, all living beings should be treated with respect and a relationshipbased on empathy should be established. In this context, we discuss all the advances made in echinodermresearch in the last 3000 years and the different uses humans made of these organisms. Finally we emphasizethat, when studying echinoderms, a reflection about our behavior as researchers is necessary, and we encouragethe use of ethically responsible research.
Studies on the immature stages of the planthopper Lepidelphax pistiae (Hemiptera: Delphacidae), a potential biocontrol agent for the aquatic weed Pistia stratiotes (Araceae) from Argentina
Studies on the immature stages of the planthopper Lepidelphax pistiae (Hemiptera: Delphacidae), a potential biocontrol agent for the aquatic weed Pistia stratiotes (Araceae) from Argentina
Marino, Ana Maria; Defea, Bárbara Soledad; Rusconi, José Matías; Cabrera Walsh, Guillermo José
Descriptions of the immature stages of the planthopper Lepidelphax pistiae Remes Lenicov (Fulgoromorpha), a specialist herbivore of Pistia stratiotes L. (Alismatales) from Argentina, are provided for the first time. P. stratiotes, or water lettuce, is an important weed in fresh water bodies of the tropics and subtropics. Newly emerged nymphs from eggs collected in the field were reared in rearing chambers. Fifth nymphal instars may be easily recognised by the whitish colour with a distinctive blackish antennal flagellum and ungues, and the relatively long frons and rostrum. Information is provided on nymphal behaviour and the main features of the fifth nymph instar that distinguish it from the two other delphacids that live and feed on plants from central and northern Argentine wetlands.
Probing the sea quark content of the proton with one-particle-inclusive processes
Probing the sea quark content of the proton with one-particle-inclusive processes
Borsa Sanjuán, Ignacio; Sassot, Rodolfo; Stratmann, Marco
We investigate the feasibility of constraining parton distribution functions in the proton through a comparison with data on semi-inclusive deep-inelastic lepton-nucleon scattering. Specifically, we reweight replicas of these distributions according to how well they reproduce recent, very precise charged kaon multiplicity measurements and analyze how this procedure optimizes the determination of the sea quark densities and improves their uncertainties. The results can help to shed new light on the long standing question on the size of the flavor and charge symmetry breaking among quarks of radiative origin. An iterative method is proposed and adopted to account for the inevitable correlation with what is assumed about the parton-To-hadron fragmentation functions in the reweighting procedure. It is shown how the fragmentation functions can be optimized simultaneously in each step of the iteration. As a first case study, we implement this method to analyze kaon production data.
Electric Dipole-Magnetic Dipole Polarizability and Anapole Magnetizability of Hydrogen Peroxide as Functions of the HOOH Dihedral Angle
Electric Dipole-Magnetic Dipole Polarizability and Anapole Magnetizability of Hydrogen Peroxide as Functions of the HOOH Dihedral Angle
Pelloni, Stefano; Provasi, Patricio Federico; Pagola, Gabriel Ignacio; Ferraro, Marta Beatriz; Lazzeretti, Paolo
The trace of tensors that account for chiroptical response of the H2O2 molecule is a function of the HO-OH dihedral angle. It vanishes at 0° and 180°, due to the presence of molecular symmetry planes, but also for values in the range 90-100° of this angle, in which the molecule is unquestionably chiral. Such an atypical effect is caused by counterbalancing contributions of diagonal tensor components with nearly maximal magnitude but opposite sign, determined by electron flow in open or closed helical paths, and associated with induced electric and magnetic dipole moments and anapole moments. For values of dihedral angle external to the 90-100° interval, the helical paths become smaller in size, thus reducing the amount of cancellation among diagonal components. Shrinking of helical paths determines the appearance of extremum values of tensor traces approximately at 50° and 140° dihedral angles.
Relation of Mycobacterium tuberculosis mutations at katG315 and inhA-15 with drug resistance profile, genetic background, and clustering in Argentina
Relation of Mycobacterium tuberculosis mutations at katG315 and inhA-15 with drug resistance profile, genetic background, and clustering in Argentina
Monteserin, Johana; Paul, Roxana; Latini, Cecilia; Símboli, Norberto; Yokobori, Noemí; Delfederico, Lucrecia; López, Beatriz; Ritacco, Gloria Viviana
We analyzed 362 isoniazid-resistant clinical isolates of Mycobacterium tuberculosis obtained countrywide for the presence of mutation at katG315 and inhA-15 in relation to genotype, pattern of phenotypic resistance to other drugs, and ability to spread. We found the following mutation frequencies: katG315MUT/inhA-15wt 53.0%, katG315wt/inhA-15MUT 27.4%, katG315wt/inhA-15wt 19.3%, and katG315MUT/inhA-15MUT only 0.3%. Mutation at katG315 associated with the LAM superfamily; mutation at inhA-15 associated with the S family and the T1 Tuscany genotype; the combination katG315wt/inhA-15wt associated with the T1Ghana genotype. Isolates harbouring katG315MUT/inhA-15wt tended to accumulateresistance to other drugs and were more frequently found in cluster; isolates harboring katG315wt/inhA-15wt were more frequently found as orphan isolates. Although epidemiological and host factors could also be modulating the events observed, in Argentina, the systematic genotyping of drug resistant clinical isolates could help to predict an enhanced risk of transmission and a propensity to develop resistance to increasing numbers of drugs.
Oxidative coupling of methane on cordierite monoliths coated with Sr/La 2 O 3 catalysts. Influence of honeycomb structure and catalyst-cordierite chemical interactions on the catalytic behavior
Oxidative coupling of methane on cordierite monoliths coated with Sr/La 2 O 3 catalysts. Influence of honeycomb structure and catalyst-cordierite chemical interactions on the catalytic behavior
Sollier, Brenda Maria del Valle; Gómez, Leticia Ester; Boix, Alicia Viviana; Miro, Eduardo Ernesto
When powder Sr/La2O3 catalysts are deposited on the walls of cordierite monoliths, an important increase in both, methane conversion and C2 yield, takes place. In this work, it is shown that this improved catalytic behavior is due to a combination of physical and chemical factors. This conclusion was drawn after performing a systematic study in which several structured formulations were catalytically evaluated and characterized using different techniques (EDX, XRD, BET, XPS, LRS), which helped us to rationalize the experimental observations. It is suggested that the honeycomb structure provides a more homogeneous gaseous flow as compared with the powder catalyst. This fact results in a better contact between reactant and catalyst surface, which in turn results in an increase of the overall reaction rate. Furthermore, it is demonstrated that the catalytic layer enrichment with Mg and Si, coming from the cordierite structure, greatly contributes to the improved catalytic behavior.
Microreactor with copper oxide nanostructured films for catalytic gas phase oxidations
Microreactor with copper oxide nanostructured films for catalytic gas phase oxidations
Papurello, Rocio; Cabello, Ana Paula; Ulla, Maria Alicia del H.; Neyertz, Claudia A.; Zamaro, Juan Manuel
Three simple gas phase based methods were applied to copper foils with parallel microchannels to induce in-situ growth of nanostructured CuOx films. One method consisted in treating with vapors of NH4OH and H2O2 (VAP); another method consisted in heating in air at 500 °C (CAL); and the third one was a sequence of both methods (CAL-VAP). The synthesized CuOx films/Cu foils were assembled as microreactors and tested for CO oxidation, showing high catalytic performance and stability in reaction. The physicochemical characteristics of the films were examined by Scanning Electron Microscopy (SEM), Temperature-Programmed Reduction (TPR), X-ray Diffraction (XRD), Laser Raman Spectroscopy (LRS), Reflectance Infrared Fourier Transformed Spectroscopy (DRIFTS) and ultrasound tests. The VAP films consisted of thick clustered nanorods containing Cu+ and Cu2 + species in the outer layer of the coating. The CAL films presented uniform growth of nanoneedles in which the outer layers were composed mainly of Cu2 +. However, by submitting the CAL sample to the VAP procedure (CAL-VAP), part of CuO was reduced to Cu4O3 species. The developed microreactors with copper oxide nanostructures directly grown on microchannels with high thermal conductivity represent a low-cost, simple alternative for application in catalytic gas-phase reactions.
Diffusion controlled LHHW kinetics. Simultaneous determination of chemical kinetic and equilibrium adsorption constants by using the Weisz-Prater approach
Diffusion controlled LHHW kinetics. Simultaneous determination of chemical kinetic and equilibrium adsorption constants by using the Weisz-Prater approach
García, Juan Rafael; Bidabehere, Claudia María; Sedran, Ulises Anselmo
A method to simultaneously determine the chemical kinetics (kCT) and Langmuir’s adsorption equilibrium (KL) constants in porous catalyst particles where chemical reactions following Langmuir-Hinshel wood-Hougen-Watson (LHHW) kinetics (first order on the concentration of the adsorbed species) proceed under the existence of diffusion mass transfer limitations was proposed. Two parameters characterize this steady state diffusion-adsorption-reaction system: the well known Thiele modulus / and the dimensionless adsorption equilibrium constant K, which is defined as the product between KL and the fluid phase concentration of the reactant (Cf). It was shown that the non-linear adsorption equilibrium is the reason that, given /, the larger the K, the flatter the concentration profile and, consequently, the volume average chemical reaction rate and the effectiveness factor are higher. Although the Weisz- Prater (W-P) criterion has been previously extended to non-linear kinetics to evaluate the relative magnitude of diffusion limitations inside porous catalyst particles, this method allows determining the kinetic and adsorption parameters by using the W-P parameter, as assessed from a few laboratory experiments. Differently from the classical W-P criterion (first order kinetics), a single value of W-P parameter below which the chemical control could be secured does not exist for LHHW kinetics. Those ‘‘limit” values depend on K and increase with it. The fact that / is independent from Cf , while K certainly depends on it, makes it easier to simultaneously determine KL and kCT under reaction conditions. When K is small (e.g., lower than 0.1), the model converges to the solutions typical in textbooks, where linear adsorption equilibrium is taken into account, which under steady state conditions only allow estimating the kCTKL product, but not the individual constants.
Some Considerations about Pain in the Child that was Born Premature
Some Considerations about Pain in the Child that was Born Premature
Gómez, María Celeste
Every single child born before completing the 37 weeks of gestational age (GA) is considered by major organizations such as UNICEF [1] and OMS [2] as premature. Because of their in maturity, these infants must face at the early beginnings of their lives hospitalization in a neonatal intensive care unit (NICU) which will take longer or lesser depending on their GA when born, their weight and their overall health condition. In that Unit they will undergo several interventions to make a diagnosis and treatments in pursuit of an adequate and soon recovery, and therefore get ready to be discharged and return home.
Chagas disease ecoepidemiology and environmental changes in northern Minas Gerais state, Brazil
Chagas disease ecoepidemiology and environmental changes in northern Minas Gerais state, Brazil
Neves Vianna, Elisa; Souza e Guimarães, Ricardo José de Paula; Souza, Christian Rezende; Gorla, David Eladio; Diotaiuti, Liléia
BACKGROUND: Triatoma sordida and Triatoma pseudomaculata are frequently captured triatomine species in the Brazilian savannah and caatinga biomes, respectively, and in Brazilian domiciles. OBJECTIVES: This study identified eco-epidemiological changes in Chagas disease in northern Minas Gerais state, Brazil, and considered the influence of environmental shifts and both natural and anthropogenic effects. METHODS: Domicile infestation and Trypanosoma cruzi infection rates were obtained from triatomines and sylvatic reservoirs during the following two time periods: the 1980s and 2007/2008. Entomological and climatic data with land cover classification derived from satellite imagery were integrated into a geographic information system (GIS), which was applied for atmospheric correction, segmentation, image classification, and mapping and to analyse data obtained in the field. Climatic data were analysed and compared to land cover classifications. RESULTS: A comparison of current data with data obtained in the 1980's showed that T. sordida colonised domiciliary areas in both periods, and that T. pseudomaculata did not colonise these areas. There was a tendency toward a reduction in T. cruzi infection rates in sylvatic reservoirs, and of triatomines captured in both households and in the sylvatic environment. T. sordida populations have reduced in the sylvatic environment, while T. pseudomaculata showed an expanding trend in the region compared to counts observed in the 1980's in the sylvatic environment. This may be related to high deforestation rates as well as gradual increases in land surface temperature (LST) and temperatures along the years. MAIN CONCLUSIONS: Our results suggest a geographical expansion of species into new biomes as a result of anthropogenic and climatic changes that directly interfere with the reproductive and infection processes of vectors.
Development and Analysis of a New Solar Radiation Atlas for Argentina from Ground-Based Measurements and CERES_SYN1deg data
Development and Analysis of a New Solar Radiation Atlas for Argentina from Ground-Based Measurements and CERES_SYN1deg data
Carmona, Facundo; Orte, Pablo Facundo; Rivas, Raúl Eduardo; Wolfram, Elian Augusto; Kruse, Eduardo Emilio
Currently, quantifying global solar radiation at surface in Argentina is crucial for the development of projects related to solar energy, calculation of evapotranspiration and eco-sustainability architecture, among other environmental issues. In recent years, several models have been developed to estimate the solar energy resources by means of various techniques, e.g. satellite imaging, kriging, or Artificial Neural Networks. The use of satellite data allows for a better spatial representation, being of great relevance in areas with lack of terrain measurements. In this paper, we use the CERES_SYN1deg to develop a new Global Solar Radiation Atlas for Argentina. In this study, we developed maps of annual and monthly mean daily global solar radiation using CERES_SYN1deg data between 2000 and 2016. In order to validate the global solar radiation data provided by CERES_SYN1deg, they were compared with ground-based measurements in the time overlap of both instruments, in four monitoring sites of the SAVER-Net project and an additional site in Tandil, which belongs to the Remote Sensing Group of IHLLA. The maps show the spatial and temporal variation of global solar radiation in Argentina. Comparisons with ground-based pyranometers reveal relative differences of around 3% at a monthly scale for all sites, while the biases can be neglected. Therefore, it is possible to conclude that the maps could be very useful for different technical and scientific purposes, and the comparison with ground-based data demonstrates CERES_SYN1deg´s reliability.
Electrophoresis characterization of Turnera sidoides L. (Passifloraceae: Turneroideae) seed storage proteins and its systematic implications
Electrophoresis characterization of Turnera sidoides L. (Passifloraceae: Turneroideae) seed storage proteins and its systematic implications
Moreno, Ercilia Maria Sara; Roggero Luque, Juan Manuel; Solis Neffa, Viviana Griselda
Twenty-four populations of Turnera sidoides were analysed, using seed storage protein fingerprinting techniques, including 19 populations of Turnera spp. and three of Piriqueta spp. for comparative purposes. The aim was to characterize the T. sidoides complex and to evaluate its profiles as a character to clarify its taxonomic position, as well as its evolutionary relationships within the genus Turnera. The present work is the first comparative study of the seed protein fingerprint in Turneroideae. The results proved that seed proteins are useful characters to discriminate between genus and species, as well as to characterize them. The finding of exclusive bands in Turnera and Piriqueta are evidence for the existence of genetic differences between genera, and support their taxonomic identity. Our results are in agreement with evolutionary tendencies of karyotype proposed for Turnera, and support the close relationships between species belonging to the same series, except T. sidoides, which should be singled out of Leiocarpae, supporting the proposal of its inclusion in an independent series.
Antitumoral effects of the alkynylphosphonate analogue of calcitriol EM1 on glioblastoma multiforme cells
Antitumoral effects of the alkynylphosphonate analogue of calcitriol EM1 on glioblastoma multiforme cells
Ferronato, María Julia; Alonso, Eliana Noelia; Salomón, Débora Gisele; Fermento, María Eugenia; Gandini, Norberto Ariel; Quevedo, Mario Alfredo; Mascaro, Evangelina; Vitale, Cristian Alejandro; Fall, Yagamare; Facchinetti, Maria Marta; Curino, Alejandro Carlos
Glioblastoma multiforme (GBM) is the worst and most common brain tumor, characterized by high proliferation and invasion rates. The current standard treatment is mainly based on chemoradiotherapy and this approach has slightly improved patient survival. Thus, novel strategies aimed at prolonging the survival and ensuring a better quality of life are necessary. In the present work, we investigated the antitumoral effect of the novel analogue of calcitriol EM1 on GBM cells employing in vitro, in silico, and in vivo assays. In vitro, we demonstrated that EM1 treatment selectively decreases the viability of murine and human tumor cells without affecting that of normal human astrocytes. The analysis of the mechanisms showed that EM1 produces cell cycle arrest in the T98G cell line, which is accompanied by an increase in p21, p27, p57 protein levels and a decrease in cyclin D1, p-Akt-S473, p-ERK1/2 and c-Jun expression. Moreover, EM1 treatment also exerts in GBM cells anti-migratory effects and decreases their invasive capacity by a reduction in MMP-9 proteolytic activity. In silico, we demonstrated that EM1 is able to bind to the vitamin D receptor with greater affinity than calcitriol. Finally, we showed that EM1 treatment of nude mice administered at 50 ug/Kg body weight during 21 days neither induces hypercalcemia nor toxicity effects. In conclusion, all the results indicate the potential of EM1 analogue as a promising therapeutic alternative for GBM treatment.
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