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Search Results: 1 - 10 of 208122 matches for " Enrique Guzmán-Gutiérrez "
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Insulin-Increased L-Arginine Transport Requires A2A Adenosine Receptors Activation in Human Umbilical Vein Endothelium
Enrique Guzmán-Gutiérrez, Francisco Westermeier, Carlos Salomón, Marcelo González, Fabián Pardo, Andrea Leiva, Luis Sobrevia
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041705
Abstract: Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1). This process involves the activation of A2A adenosine receptors (A2AAR) in human umbilical vein endothelial cells (HUVECs). Insulin increases hCAT-1 activity and expression in HUVECs, and A2AAR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A2AAR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37°C) in the absence or presence of nitrobenzylthioinosine (NBTI, 10 μmol/L, adenosine transport inhibitor) and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR), and SLC7A1 (for hCAT-1) reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent Km for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1?1606 or pGL3-hCAT-1?650 constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1?1606, and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A2AAR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.
Gestational Diabetes Reduces Adenosine Transport in Human Placental Microvascular Endothelium, an Effect Reversed by Insulin
Carlos Salomón, Francisco Westermeier, Carlos Puebla, Pablo Arroyo, Enrique Guzmán-Gutiérrez, Fabián Pardo, Andrea Leiva, Paola Casanello, Luis Sobrevia
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040578
Abstract: Gestational diabetes mellitus (GDM) courses with increased fetal plasma adenosine concentration and reduced adenosine transport in placental macrovascular endothelium. Since insulin modulates human equilibrative nucleoside transporters (hENTs) expression/activity, we hypothesize that GDM will alter hENT2-mediated transport in human placental microvascular endothelium (hPMEC), and that insulin will restore GDM to a normal phenotype involving insulin receptors A (IR-A) and B (IR-B). GDM effect on hENTs expression and transport activity, and IR-A/IR-B expression and associated cell signalling cascades (p42/44 mitogen-activated protein kinases (p42/44mapk) and Akt) role in hPMEC primary cultures was assayed. GDM associates with elevated umbilical whole and vein, but not arteries blood adenosine, and reduced hENTs adenosine transport and expression. IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios (‘metabolic phenotype’) were lower in GDM. Insulin reversed GDM-reduced hENT2 expression/activity, IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios to normal pregnancies (‘mitogenic phenotype’). It is suggested that insulin effects required IR-A and IR-B expression leading to differential modulation of signalling pathways restoring GDM-metabolic to a normal-mitogenic like phenotype. Insulin could be acting as protecting factor for placental microvascular endothelial dysfunction in GDM.
Potential Role of Sodium-Proton Exchangers in the Low Concentration Arsenic Trioxide-Increased Intracellular pH and Cell Proliferation
Carmen Aravena, Ana R. Beltrán, Marcelo Cornejo, Viviana Torres, Emilce S. Díaz, Enrique Guzmán-Gutiérrez, Fabián Pardo, Andrea Leiva, Luis Sobrevia, Marco A. Ramírez
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051451
Abstract: Arsenic main inorganic compound is arsenic trioxide (ATO) presented in solution mainly as arsenite. ATO increases intracellular pH (pHi), cell proliferation and tumor growth. Sodium-proton exchangers (NHEs) modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK) cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 μmol/L, 0–48 hours) in the absence or presence of 5-N,N-hexamethylene amiloride (HMA, 5–100 μmol/L, NHEs inhibitor), PD-98059 (30 μmol/L, MAPK1/2 inhibitor), G?6976 (10 μmol/L, PKCα, βI and μ inhibitor), or Schering 28080 (10 μmol/L, H+/K+ATPase inhibitor) plus concanamycin (0.1 μmol/L, V type ATPases inhibitor). Incorporation of [3H]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescei?nloaded cells. The Na+-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44mapk) were also determined. Lowest ATO (0.05 μmol/L, ~0.01 ppm) used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or G?6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1)-like transport dependent-increased pHi requiring p42/44mapk and PKCα, βI and/or μ activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and in circumstances where ATO, likely arsenite, is available at the drinking-water at these levels.
Reduced L-Carnitine Transport in Aortic Endothelial Cells from Spontaneously Hypertensive Rats
Rocío Salsoso, Enrique Guzmán-Gutiérrez, Pablo Arroyo, Carlos Salomón, Sonia Zambrano, María Victoria Ruiz-Armenta, Antonio Jesús Blanca, Fabián Pardo, Andrea Leiva, Alfonso Mate, Luis Sobrevia, Carmen María Vázquez
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090339
Abstract: Impaired L-carnitine uptake correlates with higher blood pressure in adult men, and L-carnitine restores endothelial function in aortic rings from spontaneously hypertensive rat (SHR). Thus, endothelial dysfunction in hypertension could result from lower L-carnitine transport in this cell type. L-Carnitine transport is mainly mediated by novel organic cation transporters 1 (Octn1, Na+-independent) and 2 (Octn2, Na+-dependent); however, their kinetic properties and potential consequences in hypertension are unknown. We hypothesize that L-carnitine transport kinetic properties will be altered in aortic endothelium from spontaneously hypertensive rats (SHR). L-Carnitine transport was measured at different extracellular pH (pHo 5.5–8.5) in the absence or presence of sodium in rat aortic endothelial cells (RAECs) from non-hypertensive Wistar-Kyoto (WKY) rats and SHR. Octn1 and Octn2 mRNA relative expression was also determined. Dilation of endothelium-intact or denuded aortic rings in response to calcitonine gene related peptide (CGRP, 0.1–100 nmol/L) was measured (myography) in the absence or presence of L-carnitine. Total L-carnitine transport was lower in cells from SHR compared with WKY rats, an effect due to reduced Na+-dependent (Na+dep) compared with Na+-independent (Na+indep) transport components. Saturable L-carnitine transport kinetics show maximal velocity (Vmax), without changes in apparent Km for Na+indep transport in SHR compared with WKY rats. Total and Na+dep component of transport were increased, but Na+indep transport was reduced by extracellular alkalization in WKY rats. However, alkalization reduced total and Na+indep transport in cells from SHR. Octn2 mRNA was higher than Octn-1 mRNA expression in cells from both conditions. Dilation of artery rings in response to CGRP was reduced in vessels from SHR compared with WKY rats. CGRP effect was endothelium-dependent and restored by L-carnitine. All together these results suggest that reduced L-carnitine transport (likely via Na+-dependent Octn2) could limit this compound's potential beneficial effects in RAECs from SHR.
Evidence of predation on the vertebra of a hadrosaurid dinosaur from the Upper Cretaceous (Campanian) of Coahuila, Mexico
Rivera-Sylva Héctor E.,Frey Eberhard,Guzmán-Gutiérrez José Rubén
Carnets de Géologie , 2009,
Abstract: In sediments of the Aguja Formation (Late Cretaceous: Campanian) at La Salada in northern part of the state of Coahuila, Mexico, numerous fossils of vertebrates have been discovered including Hadrosauridae. One hadrosaur vertebra provides evidence of predation probably by a giant alligator Deinosuchus riograndensis.
Contribución al conocimiento de los rinocerontes fósiles de la Cuenca de Tecolotlán, en el estado de Jalisco, México
Carbot-Chanona, Gerardo;Juárez-Woo, Javier;Guzmán-Gutiérrez, José Rubén;
Boletín de la Sociedad Geológica Mexicana , 2009,
Abstract: remains of teleoceras hicksi (perissodactyla, rhinocerotidae), housed at the "museo de paleontologia "in guadalajara and the "museo regional de guadalajara", recovered from the fluvial lacustrine sediments in the tecolotlán basin are described. the studied material includes a partial skull bearing p2-m3 and one lower jaw preserving i2 and p3-m3, the anterior part of an isolated lower jaw with left i2 and p3-m3, one isolated lower jaw with p3-m3 dental series in wich the symphyseal region is missing, also isolated molars, two magnus, one left metacarpus iii, and one first phalange of the right digit iii. morphological differences were observed in the material examined attributed to differences in age and/or sex of the individuals. teleoceras hicksi was found associated with dinohippus mexicanus, nannippus aztecus, neohipparion eurystyle, astrohippus stockii and borophagus secundus, suggesting a late hemphillian age for thefaunal association.
Preliminary Report on a Late Cretaceous Vertebrate Fossil Assemblage in Northwestern Coahuila, Mexico
Rivera-Sylva, Héctor E.;Frey, Eberhard;Palomino-Sánchez, Francisco J.;Guzmán-Gutiérrez, José Rubén;Ortiz-Mendieta, Jorge A.;
Boletín de la Sociedad Geológica Mexicana , 2009,
Abstract: a new vertebrate fossil assemblage of late cretaceous age is reported here. this discovery represents the results of the 2007 and 2008 field seasons in the locality known as "las jicoteas" situated in the municipality of ocampo, in northwestern coahuila, mexico. the stratigraphic sequence where this fossil fauna occurs can be correlated to the lower member of the continental aguj a formation that outcrops in the neighbouring big bend region of texas. this new fauna bears the first record of a nodosaur for mexico, and, also additional dinosaur remains attributed to the families tyrannosauridae and hadrosauridae are recorded. associated fossil taxa include lepisosteid fishes, turtles and crocodile remains. the palaeocological conditions inferred by this new faunal assemblage suggest a paralic system with prodelta, marshes, lagoons, and nearshore marine deposits.
Low Temperature Synthesis of : Effect on Its Morphological and Textural Properties
Georgina Mondragón-Gutiérrez,Daniel Cruz,Heriberto Pfeiffer,Silvia Bulbulian
Advances in Materials Science and Engineering , 2008, DOI: 10.1155/2008/908654
Abstract: Synthesis, at low temperature, of Li2SiO3 was investigated using different Li : Si molar ratios and urea, which was used as template. This new synthesis was performed in order to look for different textural and morphological properties than those obtained usually by conventional methods in this kind of ceramics. XRD and SEM analyses showed that Li2SiO3 was obtained pure and with ceramic particle morphology of hollow spheres of 2–6 m. TEM analysis showed that those spheres were composed by needle-like particles crosslinked among them. This morphology provided a high surface area, probed by N2 adsorption. Therefore, this method of synthesis may be used to obtain other similar ceramics and test them in different applications.
Dise?o óptimo evolutivo
Velázquez-Villegas, F.;Santillán-Gutiérrez, S.D.;
Ingeniería, investigación y tecnología , 2006,
Abstract: this paper reports the merging of genetic algorithms (ga) with finite element analysis (fea) as a tool of optimization for design of trusses. the development of an experimental cad tool is re ported evolutionary optmal design (dope). this cad was done using delphi (object pascal) and showed very good results in spite of such basic configuration. the results lead us to optimizate within reasonable processing time, so a fast and robust optimization method is obtained. the research actually embeds fea within the ga, and the fitness function is linked to fea, in stead of the approach of processing with ga's, confirming and redirecting with fea used in other researches. three cases of study are reported for confirming the utility of dope applied to trusses.
Shape Optimization of a Hanging Body Based on Evolutive Rules and Parametric Modeling: The Shape of a Fruit
Velázquez-Villegas F.,Santillán-Gutiérrez S.D.
Ingeniería, investigación y tecnología , 2013,
Abstract: This paper develops the shape optimization of a body, which is hanged and subjected to body forces. The geometry of the body is modeled using parametric curves B-Spline. The shape optimization is carried out modifying the boundary of the body based on the stress level calculated via Finite Element Analysis (FEA). Traditional evolutive rules are used for the optimization process; however, the method of boundary modification in the optimization process is neither traditional nor trivial. Unlike most shape optimization methods, which only use the information of boundary points in a isolated way, in this approach the geometry boundary is modified considering both points and neighborhood information.
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