507 research outputs found

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

    Get PDF
    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

    Mixing aggression intensity is associated with age at first service and floor type during gestation, with implications for sow reproductive performance

    Get PDF
    peer-reviewedAggression resulting from mixing to establish a dominance hierarchy is a major welfare concern for group-housed sows. The associated stress can negatively impact aspects of reproductive performance. Objectives of this study were to investigate associations between 1) age at first service (AFS) and mixing aggression intensity in first parity sows, 2) mixing aggression intensity and reproductive performance within and between parity one and parity two, and 3) mixing aggression intensity, floor type during gestation and reproductive performance. Gilts (n =160, hereafter referred to as sows) were mixed into stable groups of eight unfamiliar individuals approximately 4 days after artificial insemination, housed on fully slatted concrete (CON; n =80) floor uncovered or covered with rubber slat mats (RUB; n =80), and followed through two parities. Skin lesions (SLMIX; a proxy for the intensity of mixing aggression), were scored post mixing in each parity according to severity (0=no lesions to 5=severe lesions) on five body regions (ear, neck, hindquarter, rump, and belly) on the left and right sides, and at the tail/anogenital region. Total SLMIX score was calculated for each sow. Data on reproductive performance traits were acquired retrospectively from farm records for both parities. Two analyses were performed: 1) data from each parity were analysed separately and 2) SLMIX score in parity one was used to predict reproductive performance in parity two. Lower AFS was associated with a lower SLMIX score in parity one (P =0.031). There was no association between SLMIX score and reproductive performance in parity one, while sows with higher SLMIX score in parity two had a higher proportion of piglets dead during lactation (P =0.027) and a longer cycle length (P =0.003) in parity two. Sows with higher SLMIX scores in parity one had more non-productive days (P <0.001) in parity two. Concrete sows had a higher SLMIX score than RUB sows in parity one (P =0.015), but not in parity two. In addition, CON sows had a higher proportion of piglets born dead (P =0.013) compared with RUB sows in parity two. Mixing aggression has a negative influence on reproductive performance within parities, and it may also have a long-term negative carry-over effect on reproductive performance in subsequent parities. Serving gilts at younger ages could help to minimize the intensity of aggression at mixing, while housing on rubber flooring has beneficial implications for their reproductive performance

    Vegetative growth response of beets and lettuce to stored human urine

    Get PDF
    ArticleIn this work, we present the experimental results of the effect of stored human urine (SHU) on the growth of beets (Beta vulgaris L) and lettuce (Lactuca sativaL). We apply different amounts of SHU according to the recommended dose of nitrogen, considering soil from farmland and vermiculite as substrates. The last allows us to determine with high precision the isolated effect of SHU over the vegetative development of beet plants, without considering other nutrients present in common soils. Experimental results demonstrate that the application of SHU has no significant effects on lettuce vegetative growth under our soil conditions. In contrast, SHU can be used successfully as a fertilizer of beets. The optimum dose was found at 120kgN ha-1and resulted in average dry weight of 125g. However, if the dose exceeds the optimum levels, the growth of the plant is inhibited. Beets fertilized with SHU does not pose any hygienic risk for human consumption. Our findings represent a promising alternative to propose expanding the use of SHU as fertilizer in medium-sized greenhouses and to provide benefits to families in rural areas, with little or no available water supplies

    Confinement Effects in Antiferromagnets

    Full text link
    Phase equilibrium in confined Ising antiferromagnets was studied as a function of the coupling (v) and a magnetic field (h) at the surfaces, in the presence of an external field H. The ground state properties were calculated exactly for symmetric boundary conditions and nearest-neighbor interactions, and a full zero-temperature phase diagram in the plane v-h was obtained for films with symmetry-preserving surface orientations. The ground-state analysis was extended to the H-T plane using a cluster-variation free energy. The study of the finite-T properties (as a function of v and h) reveals the close interdependence between the surface and finite-size effects and, together with the ground-state phase diagram, provides an integral picture of the confinement in anisotropic antiferromagnets with surfaces that preserve the symmetry of the order parameter.Comment: 10 pages, 8 figures, Accepted in Phys. Rev.

    An approach for identifyation of areas with higher expected damage and definition of priority levels for prevention plans in Murcia Province (SE Spain)

    Get PDF
    The Murcia Region is one of the most active zones in Spain, where three earthquakes took place in 1999, 2002 and 2005. In spite of their low magnitudes (Mw 4.8), these earthquakes caused important damage, the last one reaching an EMS-98 intensity of VII. After that event, the RISMUR project started, aimed at providing a general picture of the seismic risk, which allows us to identify zones requiring a more detailed analysis of where prevention plans should be prioritized. A multidisciplinary study, starting with the seismic hazard assessment, which follows the Probabilistic Seismic Hazard Assessment methodology has been carried out at a regional scale. The expected ground motion (rock sites), for a return period of 475 years, has been characterized in terms of PGA and spectral ordinates and the corresponding maps have been drawn. In addition, a regional geotechnical study has been done and a classification of eight types of soils has been proposed, with the corresponding amplification factors. The combination of previous maps and factors, gives a new hazard map which already includes local effects. In parallel, a vulnerability assessment of the Murcian building stock is carried out, based fundamentally on the age of construction and following the EMS-98 criteria. Taking into account the expected ground motions and building vulnerabilities, the distribution of expected damage is estimated by the application of probability damage matrixes. A suite of maps representing seismic risk in terms of damage parameters for the entire region and from which we can identify the locations with higher expected damage have been obtained. We use the Coulomb stress transfer map of the region as additional criteria for defining priority areas where detailed studies should be performed. This gives information about the zones with stress load due to the previous seismicity and where new events could be triggered. The superposition of this map with the active faults of the region and the locations with higher expected damage allows us to establish a four-level priority ranking where future local-scale analyses should be made

    Neurological recovery after traumatic spinal cord injury: prognostic value of magnetic resonance

    Get PDF
    [Abstract] Study design: Retrospective observational study. Objectives: Assess the relationship between Magnetic Resonance (MR) image patterns and neurological recovery in patients with Traumatic Spinal Cord Injury (TSCI). Setting: Spinal cord injury unit in Spain. Methods: Patients admitted for acute TSCI between January 2010 and December 2018 with a MR exam performed in the acute phase were selected. Five patterns were established: normal, single-level edema, multilevel edema, hemorrhage, and spinal cord transection. Comparisons between the ASIA Injury Severity (AIS) score and Motor Index (MI) at admission and at discharge were made. Results: Collected 296 patients. Normal and cord transection patterns were excluded due to the low number of cases. Single-level edema pattern was primarily observed in cases with incomplete injuries, hemorrhage pattern in complete injuries, and multilevel edema pattern at similar percentages in complete and incomplete lesions. Improvement of the AIS score was found in 40.9% of single-level edema, 20.2% of multilevel edema, and 19.0% of hemorrhage (p = 0.042) patterns. By excluding the AIS grade D from the analyses, the figures increased to 70.3%, 52.2%, and 19.4% respectively (p < 0.001). This significant relationship was confirmed by multivariate analysis, although it was not as relevant as the examination according to ASIA-ISCoS performed at admission (p = 0.005 vs p < 0.001). Mean variation of the MI was also significantly different (p < 0.001) between the three groups: 22.6 ± 21.4 for single-level edema, 16.9 ± 21.1 for multilevel edema, and 4.5 ± 8.4 for hemorrhage. Conclusion: MR injury patterns observed at the acute phase are associated with the possibility of improvement of the AIS score and MI

    Antileucotrienos. Enfoque farmacológico. Revisión sistemática de la literatura

    Get PDF
    En cualquier proceso inflamatorio agudo o crónico hay lesión de membranas celulares y endoteliales, lo que conduce a la producción de metabolitos del ácido araqui-dónico. Se liberan de los fosfolípidos y sus metabolitos se denominan eicosanoides, los cuales comprenden las prostaglandinas, el tromboxano A2, que son derivados de la vía de la ciclooxigenasa, y los leucotrienos y las lipoxinas, que son procedentes de la vía de la lipooxigenasa. Los antileucotrienos son fármacos sintetizados para antagonizar al receptor del cistenil-leucotrieno 1. El objetivo del presente trabajo es realizar una revisión sistemática de la literatura sobre los estudios existentes actuales en el manejo de las enfermedades alérgicas más frecuentes en estos fármacos.Material y métodos: Se buscaron revisiones sistemáticas, metaanálisis y artículos doble ciego con grupo control de las revistas, utilizando las bases de datos de www.mdconsult.com, www.aha.com y www.online.ca/medline. El estudio se llevó a cabo de enero de 2014 a octubre de 2018 y se realizó en el Departamento de Farmacología de la Facultad de Medi-cina. Se describen en forma resumida los resultados de los artículos con nivel de evidencia I o II y con grado de recomendación A.Resultados: Sólo 32 artículos cumplían los criterios de inclusión. En todos los estudios, el uso de montelukast demostró la mejora en los síntomas de asma, rinitis y dermatitis, y en casi todos los estudios se recomienda la administración simultánea con aerosoles controla-dores del problema en el caso del asma, con esteroides de aplicación nasal en el caso de la rinitis y con antihistamínicos orales en el caso de la dermatitis.Discusión: Se demostró que los antileucotrienos son eficaces desde la etapa de asma leve, que disminuyen los síntomas, que reducen el número de exacerbaciones y facilitan la reduc-ción de los esteroides inhalados, así como las veces que se requiere tratamiento aliviador de los síntomas, y en general los efectos adversos son poco frecuentes como la cefalea, el dolor abdominal, las náuseas, el vómito y la diarrea.Conclusiones: Los antileucotrienos son fármacos con un amplio perfil de seguridad y efecti-vidad aprobados en todos los consensos y guías de manejo internaciones como tratamiento adicional en casos de etiología alérgica, principalmente asma y rinitis alérgica. En las revisio-nes de los últimos años se amplía su uso a dermatitis atópica y a urticaria crónica
    corecore