341 research outputs found

    U-Pb zircon SHRIMP evidences of Cambrian volcanism in the Schistose Domain within the Galicia-Tras-os-Montes Zone (Variscan Orogen, NW Iberian Peninsula)

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    SHRIMP U–Pb zircon analyses have shown the complexity of dating volcanic rocks due to the presence of inner cores within zircon crystals. Using the cathodoluminescence studies assisting ion microprobe analyses allow us to conclude that: the two low-grade metavolcanic samples from the Schistose Domain of the Galicia-TrĂĄs-os-Montes Zone in the northeast limb of the VerĂ­n-Bragança synform (NW Spain and NE Portugal) yield ages of 488.7 ± 3.7Ma and 499.8 ± 3.7Ma (lowermost Ordovician-Upper Cambrian). The Schistose Domain had been traditionally considered as a parautochthonous tectonic unit, i.e. as the stratigraphic continuation of the autochthonous underlying rocks, only locally or moderately detached from them as a result of strong dragging forces from large allochthonous units above it. Current interpretation of the Schistose Domain suggests that this domain formed the outboard edge of the Iberian terrane. Important Arenig, felsic magmatism with similar geochemical signature to the volcanic bodies in the Schistose Domain of the Galicia-TrĂĄs-os-Montes Zone (GTMSD) series is present also in the adjacent Ollo de Sapo Domain of the Central Iberian Zone. This contemporary nature of magmatic events provides an additional argument to support the “Iberian” affinity of the Schistose Domain of the Galicia-TrĂĄs-osMontes Zone. However, the Cambro–Ordovician facies are very different in the Schistose Domain with respect to the autochthonous unit, the Central–Iberian Zone, suggesting that the Schistose Domain must be considered as a major allochthonous unit with a displacement of over several tens of kilometers

    The Importance of Hydration in Wound Healing: Reinvigorating the clinical perspective

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    Balancing skin hydration levels is important as any disruption in skin integrity will result in disturbance of the dermal water balance. The discovery that a moist wound healing environment actively supports the healing response when compared to a dry environment highlights the importance of water and good hydration levels for optimal wound healing. The benefits of “wet” or “hyper-hydrated” wound healing appears to offer benefits that are similar to those offered by moist wound healing over wounds healing in a dry environment. This suggests that the presence of free water itself during wound healing may not be detrimental to healing but that any adverse effects of wound fluid on tissues is more likely related to the biological components contained within chronic wound exudate (e.g. elevated protease levels). Appropriate dressings applied to wounds must be able to absorb not only the exudate but also retain this excess fluid together with its protease solutes while concurrently preventing desiccation. This is particularly important in the case of chronic wounds where peri-wound skin barrier properties are compromised and there is increased permeation across the injured skin barrier. This review discusses the importance of appropriate levels of hydration in skin with a particular focus on the need for optimal hydration levels for effective healing

    Is selective 5-HT1F receptor agonism an entity apart from that of the triptans in antimigraine therapy?

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    Migraine is a neurovascular disorder that involves activation of the trigeminovascular system and cranial vasodilation mediated by release of calcitonin gene-related peptide (CGRP).The gold standard for acute migraine treatment are the triptans, 5-HT1B/1D/(1F) receptor agonists. Their actions are thought to be mediated through activation of: (i) 5-HT1B receptors in cranial blood vessels with subsequent cranial vasoconstriction; (ii) prejunctional 5-HT1D receptors on trigeminal fibers that inhibit trigeminal CGRP release; and (iii) 5-HT1B/1D/1F receptors in central nervous system involved in (anti)nociceptive modulation. Unfortunately, coronary arteries also express 5-HT1B receptors whose activation would produce coronary vasoconstriction; hence, triptans are contraindicated in patients with cardiovascular disease. In addition, since migraineurs have an increased cardiovascular risk, it is important to develop antimigraine drugs devoid of vascular (side) effects.Ditans, here defined as selective 5-HT1F receptor agonists, were developed on the basis that most of the triptans activate trigeminal 5-HT1F receptors, which may explain part of the triptans' antimigraine action. Amongst the ditans, lasmiditan: (i) fails to constrict human coronary arteries; and (ii) is effective for the acute treatment of migraine in preliminary Phase III clinical trials. Admittedly, the exact site of action is still unknown, but lasmiditan possess a high lipophilicity, which suggests a direct action on the central descending antinociceptive pathways. Furthermore, since 5-HT1F receptors are located on trigeminal fibers, they could modulate CGRP release.This review will be particularly focussed on the similarities and differences between the triptans and the ditans, their proposed sites of action, side effects and their cardiovascular risk profile

    Gender aspects of CGRP in migraine

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    Background: Migraine is two to three times more prevalent in women than in men, but the mechanisms involved in this gender disparity are still poorly understood. In this respect, calcitonin gene-related peptide (CGRP) plays a key role in migraine pathophysiology and, more recently, the functional interactions between ovarian steroid hormones, CGRP and the trigeminovascular system have been recognized and studied in more detail. Aims: To provide an overview of CGRP studies that have addressed gender differences utilizing animal and human migraine preclinical research models to highlight how the female trigeminovascular system responds differently in the presence of varying ovarian steroid hormones. Conclusions: Gender differences are evident in migraine. Several studies indicate that fluctuations of ovarian steroid hormone (mainly estrogen) levels modulate CGRP in the trigeminovascular system during different reproductive milestones. Such interactions need to be considered when conducting future animal and human experiments, since these differences may contribute to the development of gender-specific therapies

    Diferencias genéticas en la tolerancia a la sequía de portainjertos de Prunus spp. Papel del almendro y los ciruelos

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    El aumento de los periodos de sequĂ­a extrema que estĂĄn teniendo lugar en la cuenca mediterrĂĄnea debido al cambio climĂĄtico provoca un impacto negativo en la producciĂłn de frutales. Este escenario supone un desafĂ­o para el programa de mejora de portainjertos de Prunus spp. del Centro de InvestigaciĂłn y TecnologĂ­a Agroalimentaria de AragĂłn (CITA), marcĂĄndose como uno de sus objetivos el desarrollo de portainjertos adaptados a estas nuevas condiciones climĂĄticas. Para ello se centra en estudiar la adaptaciĂłn y tolerancia a la sequĂ­a en portainjertos hĂ­bridos, mediante la caracterizaciĂłn de su respuesta fisiolĂłgica, tanto a corto como a largo plazo, asĂ­ como determinar el papel del ĂĄcido abscĂ­sico (ABA) en dicha respuesta y cĂłmo esta fitohormona desencadena la respuesta molecular al estrĂ©s hĂ­drico, activando genes implicados en la adaptaciĂłn a la sequĂ­a y relacionados con el uso eficiente del agua. El conocimiento generado de este trabajo no solo contribuye a comprender mejor las estrategias que siguen estos portainjertos frente al estrĂ©s hĂ­drico, sino que tambiĂ©n permitirĂĄ su aplicaciĂłn en el desarrollo de marcadores moleculares Ăștiles en la selecciĂłn asistida (SAM) para la obtenciĂłn de nuevos patrones con un mayor uso eficiente del agua (UEA) tan demandados por los nuevos sistemas de producciĂłn que buscan una mayor sostenibilidad.Genetic differences in drought tolerance in Prunus spp. Rootstocks: the role of almond and plums. The increase in periods of extreme drought occurring in the Mediterranean basin due to climate change has a negative impact on fruit tree production. This scenario poses a challenge for the rootstock improvement program of Prunus spp. at the Center for Research and Agri–Food Technology of Aragon (CITA), setting one of its objectives as the development of rootstocks adapted to these new climatic conditions. To achieve this, the program focuses on studying the adaptation and drought tolerance in hybrid rootstocks by characterizing their physiological response in both the short and long term. Additionally, it aims to determine the role of abscisic acid (ABA) in this response and how this phytohormone triggers the molecular response to water stress by activating genes involved in drought adaptation and related to efficient water use. The knowledge generated from this work not only contributes to a better understanding of the strategies these rootstocks use to cope with water stress but also facilitates the development of useful molecular markers for marker–assisted selection (MAS) to obtain new rootstocks with higher water use efficiency (WUE), which is in high demand by new production systems seeking greater sustainabilityEste trabajo forma parte del Proyecto de I+D+i. RTI2018–094210–R–I00 financiado por MCIN/AEI/ 10.13039/501100011033, ademĂĄs de por el Gobierno de AragĂłn (Grupo Consolidado A12_20R).AlmendroCirueloEstrĂ©s hĂ­dricoMejora genĂ©ticaMelocotoneroRaĂ­cesAlmondBreedingPeachPlumRootsWater stressPublishe

    Pharmacological analysis of the increases in heart rate and diastolic blood pressure produced by (S)-isometheptene and (R)-isometheptene in pithed rats

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    Background: Isometheptene is a sympathomimetic drug effective in acute migraine treatment. It is composed of two enantiomers with diverse pharmacological properties. This study investigated in pithed rats the cardiovascular effects of (S)- isometheptene and (R)-isometheptene, and the pharmacological profile of the more potent enantiomer. Methods: The effects of i.v. bolus injections (0.03, 0.1, 0.3, 1 and 3 mg/kg) of isometheptene racemate, (S)-isometheptene or (R)-isometheptene on heart rate and blood pressure were analyzed in control experiments. The enantiomer producing more pronounced tachycardic and/or vasopressor responses was further analyzed in rats receiving i.v. injections of prazosin (0.1 mg/kg), rauwolscine (0.3 mg/kg), propranolol (1 mg/kg) or intraperitoneal reserpine (5 mg/kg, -24 h). Results: Compared to (R)-isometheptene, (S)-isometheptene produced greater vasopressor responses, whilst both compounds equipotently increased heart rate. The tachycardic responses to (S)-isometheptene were abolished after propranolol, but remained unaffected by the other antagonists. In contrast, the vasopressor responses to (S)-isometheptene were practically abolished after prazosin. Interestingly, after reserpine, the tachycardic responses to (S)-isometheptene were abolished, whereas its vasopressor responses were attenuated and subsequently abolished by prazosin. Conclusions: The different cardiovascular effects of the isometheptene enantiomers are probably due to differences in their mechanism of action, namely: (i) a mixed sympathomimetic action for (S)-isometheptene (a tyramine-like action and a direct stimulation of α1-adrenoceptors); and (ii) exclusively a tyramine like action for (R)-isometheptene. Thus, (R)-isometheptene may represent a superior therapeutic benefit as an antimigraine agent

    Avalanche dynamics, surface roughening and self-organized criticality - experiments on a 3 dimensional pile of rice

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    We present a two-dimensional system which exhibits features of self-organized criticality. The avalanches which occur on the surface of a pile of rice are found to exhibit finite size scaling in their probability distribution. The critical exponents are τ\tau = 1.21(2) for the avalanche size distribution and DD = 1.99(2) for the cut-off size. Furthermore the geometry of the avalanches is studied leading to a fractal dimension of the active sites of dBd_B = 1.58(2). Using a set of scaling relations, we can calculate the roughness exponent α=D−dB\alpha = D - d_B = 0.41(3) and the dynamic exponent z=D(2−τ)z = D(2 - \tau) = 1.56(8). This result is compared with that obtained from a power spectrum analysis of the surface roughness, which yields α\alpha = 0.42(3) and zz = 1.5(1) in excellent agreement with those obtained from the scaling relations.Comment: 7 pages, 8 figures, accepted for publication in PR
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