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Search Results: 1 - 10 of 12617 matches for " Rocio Garcia-Villalba "
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Olive oil's bitter principle reverses acquired autoresistance to trastuzumab (Herceptin?) in HER2-overexpressing breast cancer cells
Javier A Menendez, Alejandro Vazquez-Martin, Ramon Colomer, Joan Brunet, Alegria Carrasco-Pancorbo, Rocio Garcia-Villalba, Alberto Fernandez-Gutierrez, Antonio Segura-Carretero
BMC Cancer , 2007, DOI: 10.1186/1471-2407-7-80
Abstract: Semi-preparative HPLC was used to isolate EVOO polyphenols (i.e., tyrosol, hydroxytyrosol, oleuropein). Both the anti-proliferative and the pro-apoptotic effects of EVOO phenolics were evaluated by using MTT-based quantification of metabolically viable cells and ELISA-based detection of histone-associated DNA fragments, respectively. The nature of the interaction between oleuropein aglycone and the anti-HER2 monoclonal antibody trastuzumab (Herceptin?) was mathematically evaluated by the dose-oriented isobologram technique. HER2-specific ELISAs were employed to quantitatively assess both the basal cleavage of the HER2 extracellular domain (ECD) and the expression level of total HER2. The activation status of HER2 was evaluated by immunoblotting procedures using a monoclonal antibody specifically recognizing the tyrosine phosphorylated (Phosphor-Tyr1248) form of HER2.Among EVOO polyphenols tested, oleuropein aglycone was the most potent EVOO phenolic in decreasing breast cancer cell viability. HER2 gene-amplified SKBR3 cells were ~5-times more sensitive to oleuropein aglycone than HER2-negative MCF-7 cells. Retroviral infection of the HER2 oncogene in MCF-7 cells resulted in a "SKBR3-assimilated" phenotype of hypersensitivity to oleuropein aglycone. An up to 50-fold increase in the efficacy of trastuzumab occurred in the presence of oleuropein aglycone. A preclinical model of acquired autoresistance to trastuzumab (SKBR3/Tzb100 cells) completely recovered trastuzumab sensitivity (> 1,000-fold sensitization) when co-cultured in the presence of oleuropein aglycone. Indeed, the nature of the interaction between oleuropein aglycone and trastuzumab was found to be strongly synergistic in Tzb-resistant SKBR3/Tzb100 cells. Mechanistically, oleuropein aglycone treatment significantly reduced HER2 ECD cleavage and subsequent HER2 auto-phosphorylation, while it dramatically enhanced Tzb-induced down-regulation of HER2 expression.Olive oil's bitter principle (i.e., oleuropein a
tabAnti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO)
Javier A Menendez, Alejandro Vazquez-Martin, Rocio Garcia-Villalba, Alegria Carrasco-Pancorbo, Cristina Oliveras-Ferraros, Alberto Fernandez-Gutierrez, Antonio Segura-Carretero
BMC Cancer , 2008, DOI: 10.1186/1471-2407-8-377
Abstract: Solid phase extraction followed by semi-preparative high-performance liquid chromatography (HPLC) was used to isolate phenolic fractions from commercial EVOO. Analytical capillary electrophoresis coupled to mass spectrometry was performed to check for the composition and to confirm the identity of the isolated fractions. EVOO polyphenolic fractions were tested on their tumoricidal ability against HER2-negative and HER2-positive breast cancer in vitro models using MTT, crystal violet staining, and Cell Death ELISA assays. The effects of EVOO polyphenolic fractions on the expression and activation status of HER2 oncoprotein were evaluated using HER2-specific ELISAs and immunoblotting procedures, respectively.Among the fractions mainly containing the single phenols hydroxytyrosol and tyrosol, the polyphenol acid elenolic acid, the lignans (+)-pinoresinol and 1-(+)-acetoxypinoresinol, and the secoiridoids deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (i.e. secoiridoids and lignans) were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation occurred regardless the molecular mechanism contributing to HER2 overexpression (i.e. naturally by gene amplification and ectopically driven by a viral promoter). Pre-treatment with the proteasome inhibitor MG132 prevented EVOO polyphenols-induced HER2 depletion.The ability of EVOO-derived polyphenols to inhibit HER2 activity by promoting the proteasomal degradation of the HER2 protein itself, together with the f
DNS of vertical plane channel flow with finite-size particles: Voronoi analysis, acceleration statistics and particle-conditioned averaging
Manuel Garcia-Villalba,Aman G. Kidanemariam,Markus Uhlmann
Physics , 2012, DOI: 10.1016/j.ijmultiphaseflow.2012.05.007
Abstract: We have performed a direct numerical simulation of dilute turbulent particulate flow in a vertical plane channel, fully resolving the phase interfaces. The flow conditions are the same as those in the main case of "Uhlmann, M., Phys. Fluids, vol. 20, 2008, 053305", with the exception of the computational domain length which has been doubled in the present study. The statistics of flow and particle motion are not significantly altered by the elongation of the domain. The large-scale columnar-like structures which had previously been identified do persist and they are still only marginally decorrelated in the prolonged domain. Voronoi analysis of the spatial particle distribution shows that the state of the dispersed phase can be characterized as slightly more ordered than random tending towards a homogeneous spatial distribution. It is also found that the p.d.f.'s of Lagrangian particle accelerations for wall-normal and spanwise directions follow a lognormal distribution as observed in previous experiments of homogeneous flows. The streamwise component deviates from this law presenting significant skewness. Finally, a statistical analysis of the flow in the near field around the particles reveals that particle wakes present two regions, a near wake where the velocity deficit decays as 1/x and a far wake with a decay of approximately 1/(x*x).
Spatial and temporal scales of force and torque acting on wall-mounted spherical particles in open channel flow
Clemens Chan-Braun,Manuel Garcia-Villalba,Markus Uhlmann
Physics , 2013, DOI: 10.1063/1.4813806
Abstract: Data from direct numerical simulation of open channel flow over a geometrically rough wall at a bulk Reynolds number of 2900, generated by Chan-Braun et al. ["Force and torque acting on particles in a transitionally rough open-channel flow", J. Fluid Mech. 684, 441--474 (2011), 10.1017/jfm.2011.311] are further analysed with respect to the time and length scales of force and torque acting on the wall-mounted spheres. For the two sizes of spheres in a square arrangement (11 and 49 wall units in diameter, yielding hydraulically smooth and transitionally rough flow, respectively), the spatial structure of drag, lift and spanwise torque is investigated. The auto-correlation and spectra in time as well as the space-time correlation and convection velocities are presented and discussed. It is found that the statistics of spanwise particle torque are similar to those of shear stress at a smooth wall. Particle drag and lift are shown to differ from spanwise particle torque, exhibiting considerably smaller time and length scales; the convection velocities of drag and lift are somewhat larger than those of spanwise torque. Furthermore, correlations between the flow field and particle-related quantities are presented. The spatial structure of the correlation between streamwise velocity and drag/spanwise torque features elongated shapes reminiscent of buffer-layer streaks. The correlation between the pressure field and the particle drag exhibits two opposite-signed bulges on the upstream and downstream sides of a particle.
Characteristics of GaN Thin Films Using Magnetron Sputtering System  [PDF]
Hasina F. Huq, Rocio Y. Garza, Roman Garcia-Perez
Journal of Modern Physics (JMP) , 2016, DOI: 10.4236/jmp.2016.715178
Abstract: The paper presents a polycrystalline GaN thin film with a hexagonal wurtzite structure under the optimized sputtering conditions of 40 W RF power, 5 mT working pressure, using pure nitrogen gas with a substrate temperature of 700°C. The study examines the effects of surface disorders and incorporates it in the thin films characteristics. A radio frequency (RF) Ultra High Vacuum (UHV) Magnetron Sputtering System has been used for the deposition of Gallium Nitride (GaN) on silicon, sapphire and glass substrates with different parameters. The power is varied from 40 W to 50 W, and the pressure from 4 mT to 15 mT. The effects of the RF sputtering powers and gas pressures on the structural properties are investigated experimentally. Sputtering at a lower RF power of 15 W does increase the N atomic percentage, however the deposition rate is substantially slower and the films are amorphous. GaN deposited on both silicon and sapphire wafer resulted in thin films close to stoichiometric once the N2 concentration is 60% or higher. It is also observed that the substrate cooling/heating effects improve the quality of the thin films with fewer defects present at the surface of the GaN epi-structure.
The Risks We Dread: A Social Circle Account
Mirta Galesic, Rocio Garcia-Retamero
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032837
Abstract: What makes some risks dreadful? We propose that people are particularly sensitive to threats that could kill the number of people that is similar to the size of a typical human social circle. Although there is some variability in reported sizes of social circles, active contact rarely seems to be maintained with more than about 100 people. The loss of this immediate social group may have had survival consequences in the past and still causes great distress to people today. Therefore we hypothesize that risks that threaten a much larger number of people (e.g., 1000) will not be dreaded more than those that threaten to kill “only” the number of people typical for social circles. We found support for this hypothesis in 9 experiments using different risk scenarios, measurements of fear, and samples from different countries. Fear of risks killing 100 people was higher than fear of risks killing 10 people, but there was no difference in fear of risks killing 100 or 1000 people (Experiments 1–4, 7–9). Also in support of the hypothesis, the median number of deaths that would cause maximum level of fear was 100 (Experiments 5 and 6). These results are not a consequence of lack of differentiation between the numbers 100 and 1000 (Experiments 7 and 8), and are different from the phenomenon of “psychophysical numbing” that occurs in the context of altruistic behavior towards members of other communities rather than in the context of threat to one's own community (Experiment 9). We discuss several possible explanations of these findings. Our results stress the importance of considering social environments when studying people's understanding of and reactions to risks.
Lifetime of micrometer-sized drops of oil pressed by buoyancy against a planar interface
Clara Rojas,German Urbina-Villalba,Maximo Garcia-Sucre
Physics , 2010, DOI: 10.1103/PhysRevE.81.016302
Abstract: Emulsion Stability Simulations (ESS) are used to estimate the coalescence time of one drop of hexadecane pressed by buoyancy against a planar water/hexadecane interface. In the present simulations the homophase is represented by a big drop of oil at least 500 times larger than the approaching drop ($1\,\mu$m to $10\,\mu$m). Both deformable and non-deformable drops are considered along with six different diffusion tensors. In each case van der Waals, electrostatic, steric and buoyancy forces are taken into account. The coalescence times are estimated as the average of 1000 random walks. It is found that the repulsive potential barrier has a significant influence in the results. The experimental data can only be reproduced assuming negligible repulsive barriers, as well as non-deformable drops that move with a combination of Stokes and Taylor tensors as they approach the interface.
Influence of the time-dependent surfactant adsorption on the lifetime of a drop pressed by buoyancy against a planar interface
Clara Rojas,Maximo Garcia-Sucre,German Urbina-Villalba
Physics , 2013,
Abstract: Emulsion Stability Simulations (ESS) of deformable droplets are used to study the influence of the time-dependent adsorption on the coalescence time of a 200-$\mu$m drop of soybean oil pressed by buoyancy against a planar water/oil interface. The interface is represented by a 5000-$\mu$m drop of oil fixed in the space. The movement of the small drop is determined by the interaction forces between the drops, the buoyancy force, and its thermal interaction with the solvent. The interaction forces depend on the surface concentration of surfactant molecules at the oil/water interfaces. Assuming diffusion limited adsorption, the surface excess of the surfactant becomes a function of its apparent diffusion constant, $D_{app}$. Distinct probability distributions of the coalescence time are obtained depending on the magnitude of $D_{app}$. The origin and the significance of these distributions are discussed.
Benign retrorectal tumours: Contribution of laparoscopic approach  [PDF]
Victor J. Ovejero-Gomez, M. V. Bermudez-Garcia, L. Martin-Cuesta, A. Güezmes, J. Villalba, A. Ingelmo, J. M. Bajo-Arenas
Case Reports in Clinical Medicine (CRCM) , 2013, DOI: 10.4236/crcm.2013.27111
Abstract: Introduction: Presacral tumours are extremely rare entities as the asymptomatic retrorectal mass, although its clinical presentation includes infectious complications and signs of malignant degeneration. Magnetic resonance imaging is the most efficient imaging study for its diagnosis. The treatment of choice is complete surgical excision and traditional approaches are mainly through abdominal, posterior and perineal approach, depending on anatomical characteristics of the lesion. Laparoscopic excision of these retrorectal lesions has been reported in a few cases. Patients and methods: We report two cases of 38 and 24-year-old women who complained of anorectal symptoms and were diagnosed as retrorectal tumour by imaging studies. One of them was infected. Both cases were resected by means of laparoscopic techniques. There was no surgical complication and they were discharged on the 3rd and 4th postoperative day, respectively. Histopathologic findings revealed benign cystic teratoma in both cases. A follow-up after 36 months showed no recurrence. Our surgical endoscopic technique and a brief review of perioperative cares are presented and discussed. Discussion: Laparoscopic excision could be indicated in selected retrorectal tumours and a great surgeon’s resolve is always required. A meticulous dissection must be performed in order to identify and preserve vital structures. It’s only absolute contraindications seemed to be the suspicion of malignancy and operative inexperience. Conclusions: The complete laparoscopic removal of presacral lesions is a responsible surgical procedure which offers advantages from the sanitary and aesthetic point of view. This new endoscopic indication could be considered probably as a better technique than open approach in selected patients.

Kinetics of antibody-induced modulation of respiratory syncytial virus antigens in a human epithelial cell line
Rosa E Sarmiento, Rocio G Tirado, Laura E Valverde, Beatriz Gómez-Garcia
Virology Journal , 2007, DOI: 10.1186/1743-422x-4-68
Abstract: Interaction of anti-RSV polyclonal IgG with RSV HEp-2 infected cells induced relocalization and aggregation of viral glycoproteins in the plasma membrane formed patches that subsequently produced caps or were internalized through clathrin-mediated endocytosis participation. Moreover, the concentration of cell surface RSV Ag-Abs and intracellular viral proteins showed a time dependent cyclic variation and that anti-RSV IgG protected HEp-2 cells from viral-induced death.The results from this study indicate that interaction between RSV cell surface proteins and specific viral antibodies alter the expression of viral antigens expressed on the cells surface and intracellular viral proteins; furthermore, interfere with viral induced destruction of the cell.Antibody-induced modulation of antigen is a complex biological phenomenon closely resembling other receptor-ligand interactions. Following exposure to specific antibodies, surface antigens are usually redistributed on the cell surface and are internalized or expelled into the extracellular medium [1,2]. These phenomena have been widely reported in virus systems [3-5], the best studied being an alpha herpes; in pseudorabies [6-9]. In that system, following exposure to specific antibodies, cell-surface antigens are usually redistributed with the membrane-bound viral glycoproteins aggregating to form patches on the cell surface. In fibroblasts and epidermoid cells, the patches subsequently polarize to one area of the cell, thus producing caps that are shed into the extracellular space [6-9]. In contrast, in monocytes, glycoprotein patches do not form caps, but instead collect in regions of the plasma membrane which are specialized for internalization through clathrin-coated pits. After the clathrin coated pits are introduced into the cell, the antibody-antigen complexes are degraded and the glycoproteins are directed back to the plasma membrane [8-10].Respiratory syncytial virus (RSV) is an enveloped pneumovirus classified
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