400 research outputs found

    Changes induced by glucose in the plasma membrane properties of pancreatic islets

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    Partially purified membranes obtained from rat pancreatic isolated islets preincubated for 3 min with 3.3 and 16.6 mM glucose were labelled with 1,6-diphenyl-1,3,5-hexatriene to study fluorescence polarization. Other islets, incubated for 5 min with the same glucose concentration, were extracted and phospholipids separated by thin-layer chromatography. The composition of phospholipids of fatty acids was then studied by gas-liquid chromatography. Arrhenius plots of the microviscosity in membranes obtained from islets exhibited two components, a steeper slope below 18 degrees C and a gentler slope above 18 degrees C, indicating greater flow activation energy at temperatures below the transition point. Exposure of islets to 16.6 mM glucose significantly increased the flow activation energy (delta E), below and above the transition point. Islets incubated for 5 min with 16.6 mM glucose showed an increase in the percentage composition of 12:0 and 18:2 together with a decrease in the 20:2 W6 and 22:3 W3 fatty acids esterified to phospholipids. Regardless of these changes, no significant alterations occurred in the proportion of saturated fatty acids or in the double bond index; these measurements therefore did not account for the effects of glucose concentration in flow activation energy. The thermotropic changes reported here might be the consequence of some degree of disorder induced by glucose upon the membrane structure. This order alteration could either favor the membrane fusion which occurs during the emiocytosis or only reflects the consequence of such a process

    Oxidative Stress in Cystic Fibrosis

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    Airway infection leads to progressive damage of the lungs in patients with cystic fibrosis (CF). Oxidative stress has been implicated as a causative factor in the aetiology of that process. Supplementation with antioxidant micronutrients (vitamin E, vitamin C, ß-carotene and selenium), docosahexaenoic acid or glutathione might therefore be helpful in maintaining an adequate redox balance. Current literature suggests a relationship between oxidative status and lung function. In this chapter we will summarize the main pathways of oxidative stress, focusing on results of new antioxidant treatments

    Tectónica activa de la Cuenca de Málaga: evidencias en marcadores morfotectónicos (Cordillera Bética Occidental, España)

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    The Malaga Basin is located in the westernmost part of the Betic Cordillera. This alpine cordillera in the south of Spain is the most active region of the Iberian Peninsula. Some of the most destructive earthquakes occurred historically in Spain took place within the Malaga Basin. In this work we focus on geomorphic and morphotectonic observations in the aim of finding active tectonic structures that could be seismogenic sources. First, we study the spatial arrangement and age of the Quaternary alluvial fan system as well as the drainage pattern of the basin, followed by the analysis of the distribution of regional markers like marine erosive surfaces and the extend of Pliocene marine deposits in the Malaga Basin. The tectonic structures inferred as active by the morphotectonic analysis are grouped into four main families: N60º-85ºE folds associated with blind thrust faults, N20º-30ºE and N40º-50ºE high angle dip-slip faults, and N165º-170ºE tear faults. Finally, their seismic potential in terms of maximum moment magnitude (Mw) is assessed by means of empirical relationships, varying between 6.0 and 7.0 depending on the hypothesis considered.La cuenca de Málaga se sitúa en la parte más occidental de la cordillera Bética. En esta cordillera alpina del sur de España se han localizado algunos de los terremotos más destructivos ocurridos históricamente en la península Ibérica. En este trabajo se estudian algunos de los aspectos geomorfológicos de la cuenca del Málaga con el fin de identificar las estructuras tectónicas activas que pudiesen ser fuentes sismogénicas. Se estudia la distribución y edad del sistema de abanicos aluviales de la cuenca, así como la red de drenaje. También se analiza la distribución regional de marcadores tectónicos pliocenos, como superficies de erosión marina y los depósitos sedimentarios de este periodo transgresivo. Se han identificado varias estructuras tectónicas activas que han sido agrupadas en cuatro familias: pliegues N60º-85ºE asociados con falla inversas ciegas, fallas de alto buzamiento con salto en la vertical N20º-30ºE y N40º-50ºE, y fallas de transferencia N165º-170ºE. En base a relaciones empíricas se ha estimado un potencial sísmico para las fallas identificadas, obteniéndose valores de magnitud momento (Mw) entre 6,0 y 7,0

    Factores de riesgo asociados con bacteriemia nosocomial en recién nacidos de bajo peso al nacimiento. Hospital Grady Memorial, Atlanta

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    ResumenIntroducciónLa bacteriemia nosocomial es una causa frecuente de infección nosocomial en los recién nacidos admitidos en las unidades de cuidados intensivos neonatales y está asociada con factores de riesgo, reconocidos y no reconocidos, de infección nosocomial. Aún existen pocas evidencias sobre los factores de riesgo de bacteriemia nosocomial en recién nacidos de bajo peso al nacimiento.ObjetivosInvestigar factores de riesgo de bacteriemia nosocomial en neonatos con un peso inferior a 1.500 g ingresados en la unidad de cuidados intensivos neonatal.MétodosSe realizó un estudio prospectivo en recién nacidos de bajo peso al nacimiento (≤ 1.500 g) durante 22 meses. Para determinar la asociación estadística entre la bacteriemia nosocomial y los factores de riesgo perinatales y nosocomiales, se llevó a cabo un análisis bivariante de regresión logística (método de regresión por pasos).ResultadosSe estudió a un total de 72 pacientes con bacteriemia nosocomial y 174 sin ella. La permanencia del catéter umbilical un tiempo mayor o igual a 7 días y la permanencia del catéter periférico arterial durante un día o más resultaron ser los factores independientemente asociados con bacteriemia nosocomial.ConclusiónEl mantenimiento del catéter umbilical más de 7 días, la permanencia del catéter periférico arterial más de 1 día y el peso al nacimiento inferior a 1.500 g fueron factores determinantes de bacteriemia nosocomial. Por la importancia de estas técnicas invasivas como fuente de bacteriemia nosocomial, es preciso revisar su tiempo de permanencia con el objetivo de disminuir la incidencia de bacteriemia nosocomial.AbstractBackgroundNosocomial bloodstream infections occur frequently in Neonatal Intensive Care Units and are associated with recognized and unrecognized risk factors. Little has been published regarding risk factors for bloodstream infections in low birth weight neonates.ObjectiveTo investigate risk factors for bloodstream infection in neonates < 1,500 g admitted at a Neonatal Intensive Care Unit.MethodsA prospective study was undertaken in low birth weight neonates (< 1,500g) during a 22 months period. Bivariant, and logistic regresion (stepwise procedure) analysis was used to determine the significance association of bloodstream infection and perinatal and nosocomial risk factors.ResultsA total of 72 patiens with nosocomial bacteriemia and 147 non bacteriemic patients were studied. Independent risk factors associated with bloodstream infection were birth weight, persistence of umbilical catheter > 7 days and persistence of peripheral arterial catheter > 1 day.ConclusionsThe uses of umbilical catheter > 7 days, peripheral arterial catheter > 1 day and birth weight < 1,500 g were significant determinants of nosocomial bloodstream infection risk. Because of the importance of invasive procedures as a source of nosocomial bloodstream infections, the lines duration needs to be reviewed with the aim of reducing the incidence of blood stream infection

    Aprendizaje interdisciplinar de la electrónica y las comunicaciones

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    En este proyecto de innovación docente se pretende profundizar en el conocimiento de la base teórica, la construcción de los modelos matemáticos físicos que son la base de los diseños electrónicos, mediante el montaje, presentación, simulación y experimentación. El procedimiento se basa en la realización de medidas experimentales básicas a principio de curso y en las aplicaciones interdisciplinares a final de curso, así como disponer de todo el material vía Internet para motivar el aprendizaje del alumno.The aim of this teaching innovation project is to look for deeply into knowledge about the theoretical base and construction of mathematical models that are the basis of electrical design, making use of setups, lectures, simulations and experimentations. The procedure is based upon the execution of essential experimental measurements at the beginning of the school year and on interdisciplinary applications at the end of it, all complemented with related Internet resources targeted to improve student motivation

    Paleoseismological evidence of holocene activity of the Los Tollos fault (Murcia, se Spain): a lately formed quaternary tectonic feature of the eastern betic shear zone

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    The Los Tollos Fault is a recent and important feature of the Eastern Betic Shear Zone, one of the major tectonic structures in South Iberia accommodating the convergence between Nubian and Eurasian plates in the western Mediterranean. The Los Tollos Fault became active by the end of Middle Pleistocene introducing some paleogeographical modifications. Previously mapped as a secondary normal fault related to the Carrascoy Fault, recent research evidences that the Los Tollos Fault is an independent Holocene active left-lateral reverse fault extending for at least 15 km. Data analysis from 4 trenches dug across the fault has revealed the occurrence of at least two paleo-earthquake events during the Holocene. The most recent event is dated between 2,740 and 2,140 yr BP (8th to 2nd centuries BC). The size of the paleoevents is calculated to be Mw 6.3 – 6.6 following empirical regressions on surface rupture length. The recurrence interval is estimated to be between 2,200-6,860 years, fitting a slip rate for the fault between 0.12 and 0.17 mm/yr. Such parameters highlight the Los Tollos Fault as a tectonic structure with a considerable activity located relatively close to densely populated areas. These seismogenic parameters should be considered in future reassessments of the seismic hazard of the regionThis work forms part of the research activities carried out in the FASEGEO Project (CGL2009-09726) funded by the Spanish Ministry of Science and Innovatio

    Characterization of the shallow subsurface structure across the Carrascoy Fault System (SE Iberian Peninsula) using P-wave tomography and Multichannel Analysis of Surface Waves

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    The seismicity in the SE Iberian Peninsula is distributed parallel to the coast in a well-developed strike-slip fracture system known as the Eastern Betic Shear Zone (EBSZ). This work focuses on the characterization of the shallow subsurface structure of the Algezares-Casas Nuevas Fault, within the Carrascoy Fault System of the EBSZ. The Carrascoy Fault borders the Guadalentín Depression to the south, which is a densely populated area with extensive agricultural activity. Therefore, this faults system represents a seismic hazard with significant social and economic implications. We have constructed two velocity-depth models based on P-wave tomography and Multichannel Analysis of Surface Waves (MASW) acquired from seismic reflection data. The resulting velocity models have allowed us to interpret the first ~250m depth and have revealed: i) the thickness of the critical zone; ii) the geometry of the Algezares-Casas Nuevas Fault; iii) the depth of the Messinian/Tortonian contact and iv) the presence of blind thrusts and damage zones under the Guadalentín Depression. Our results have also helped us to estimate an apparent vertical slip rate of 0.66±0.06m/ky for the Algezares-Casas Nuevas Fault since 209.1±6.2ka. Our results provide a methodological and backflow protocol to study the shallow subsurface of active faults, complementing previous geological models based on paleoseismological trenches, and can be used to improve the seismic hazard assessment of tectonically active regions around the world

    Compilation of parameterized seismogenic sources in Iberia for the SHARE European-scale seismic source model.

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    Abstract: SHARE (Seismic Hazard Harmonization in Europe) is an EC-funded project (FP7) that aims to evaluate European seismic hazards using an integrated, standardized approach. In the context of SHARE, we are compiling a fully-parameterized active fault database for Iberia and the nearby offshore region. The principal goal of this initiative is for fault sources in the Iberian region to be represented in SHARE and incorporated into the source model that will be used to produce seismic hazard maps at the European scale. The SHARE project relies heavily on input from many regional experts throughout the Euro-Mediterranean region. At the SHARE regional meeting for Iberia, the 2010 Working Group on Iberian Seismogenic Sources (WGISS) was established; these researchers are contributing to this large effort by providing their data to the Iberian regional integrators in a standardized format. The development of the SHARE Iberian active fault database is occurring in parallel with IBERFAULT, another ongoing effort to compile a database of active faults in the Iberian region. The SHARE Iberian active fault database synthesizes a wide range of geological and geophysical observations on active seismogenic sources, and incorporates existing compilations (e.g., Cabral, 1995; Silva et al., 2008), original data contributed directly from researchers, data compiled from the literature, parameters estimated using empirical and analytical relationships, and, where necessary, parameters derived using expert judgment. The Iberian seismogenic source model derived for SHARE will be the first regional-scale source model for Iberia that includes fault data and follows an internationally standardized approach (Basili et al., 2008; 2009). This model can be used in both seismic hazard and risk analyses and will be appropriate for use in Iberian- and European-scale assessments

    Evaluación urodinámica y comparativa de la calidad de vida en pacientes con trastorno de vaciamiento vesical sometidos a terapia InterStim, Medtronic®

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    ResumenAntecedentesDesde 1980 la terapia de neuroestimulación sacra ha demostrado ser una terapia válida y alternativa en el manejo de los trastornos miccionales por patología del tracto urinario bajo, siendo sus principales indicaciones la retención urinaria idiopática, la incontinencia de urgencia y la incontinencia fecal. En nuestro país sigue siendo una terapia novedosa y no se cuenta aún con estudios que evalúen esta eficacia en términos de calidad de vida o con parámetros cuantitativos.Objetivo del estudioEstablecer la eficacia de la terapia de neuroestimulación sacra tipo InterStim, Medtronic®, en el manejo de los pacientes con trastornos de vaciamiento vesical, efectuando un análisis urodinámico y de la calidad de vida comparativo previo y posterior al tratamiento, determinando los volúmenes miccionales, los períodos de incontinencia, la satisfacción del paciente y la calidad de vida.Material y métodosDesde enero de 2010 hasta junio de 2013, en el Hospital Central Militar se realizó evaluación urodinámica y comparativa de la calidad de vida mediante el empleo del instrumento SF-36 v2 (versión mexicana) e ICIQSF, en los pacientes que presentaron trastorno de vaciamiento vesical de etiología no obstructiva y que fueron refractarios a tratamiento médico.ResultadosSe incluyeron 10 pacientes en el estudio, bajo los siguientes diagnósticos: disinergia detrusor-esfínter, vejiga hiperactiva y retención urinaria no obstructiva, ubicados por género (2 masculinos y 8 femeninos). En la totalidad de los pacientes se presentó mejoría del 50% o superior durante la fase de prueba de la terapia de neuroestimulación, y se colocó fase definitiva con los siguientes resultados: se obtuvieron resultados equivalentes al 50-65% de mejoría en los parámetros cualitativos de función física, función social y rol emocional, así como en las variables cuantitativas de volumen de vaciamiento, eficacia de vaciamiento y disminución de los períodos de incontinencia.DiscusiónComo se ha establecido a nivel de la literatura mundial, nuestros resultados fueron similares en el efecto benéfico y la eficacia en la calidad de vida e incontinencia urinaria, respectivamente, y se reportan porcentajes de éxito mayores al 50% en el cese total de los episodios de incontinencia.ConclusionesLa neuromodulación mediante la estimulación del nervio sacro es una forma exitosa de tratamiento en los trastornos de vaciamiento vesical de etiología no obstructiva y refractaria al tratamiento médico, es segura, mínimamente invasiva y de fácil aplicación, y mejora la calidad de vida de los pacientes. Sin embargo, es necesario realizar estudios aleatorizados y que consideren parámetros objetivos (urodinámicos), así como las complicaciones posibles a mediano y largo plazo en este tipo de terapia.AbstractBackgroundSince 1980, sacral neuromodulation therapy has been shown to be a valid alternative therapy in the management of urinary disorders due to lower urinary tract pathology, and its primary indications are: idiopathic urinary retention, urge incontinence, and fecal incontinence. It is still considered a novel therapy in Mexico and there are no studies using quantitative parameters that evaluate its efficacy in terms of quality of life.AimsTo establish the efficacy of the Medtronic InterStim® sacral neuromodulation therapy in the management of patients with bladder voiding disorders through urodynamic and quality of life analyses before and after treatment. Urine volume, periods of incontinence, patient satisfaction, and quality of life were determined.MethodsA comparative urodynamic and quality of life evaluation was carried out using the SF-36 v2 (Mexican version) and the ICIQSF instruments on patients presenting with nonobstructive bladder voiding disorders that were refractory to medical treatment.ResultsTen patients with the following diagnoses were included in the study: detrusor sphincter dyssynergia, overactive bladder, and nonobstructive urinary retention. Two of the patients were men and 8 were women. There was a 50% or greater improvement in all 10 patients during the test phase of the neuromodulation therapy and the definitive placement phase produced the following results: a 50-65% improvement in the qualitative parameters of physical function, social function, and emotional role, as well as in the quantitative variables of voiding volume, voiding efficacy, and reduced periods of incontinence.DiscussionOur results were similar to those established in the international literature in relation to the beneficial effect on quality of life and efficacy in urinary incontinence management; the literature reports success percentages in the complete cessation of incontinence episodes at above 50%.ConclusionsNeuromodulation through sacral nerve stimulation is a successful form of treatment of nonobstructive and medical treatment-refractory bladder voiding disorders. It is safe, minimally invasive, and easy to apply and it improves patient quality of life. Nevertheless, further randomized studies on this type of therapy need to be conducted that take into account objective parameters (urodynamics) and possible medium and long-term complications
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