84 research outputs found

    Preliminary Studies of the Toxicity of Agaricus Bisporous Aqueous Enzymatic Extracts (AbAEE) In Rats

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    The health benefits of extracts from Agaricus bisporus greatly extend its use as components of new functional foods for the treatment and prevention of diseases, rather than restricting it to a good food with high nutritional value and good flavor. A. bisporus aqueous enzymatic extracts (AbAEE) have unique flavor, good taste, and health benefits which makes it a good candidate for its incorporation in different matrices for development of new functional foods and nutraceuticals. The potential use of AbAEE as nutraceutical or incorporated as a part of new functional foods requires its characterization and a subsequent food safety study. The focus of this paper was to carry out a preliminary toxicological study on experimental animals (rats in this case) by acute and sub-chronic oral administration. To evaluate potential adverse effects of AbAEE at high doses the acute toxic class method was used. After administration of the preset doses, behavior changes, toxic symptoms, and deaths were observed continuously for 1 h after treatment and then intermittently at 4th, 8th and 24th h. After these initial observations, the rats were further observed for up to 14 consecutive days for any signs of toxicity and/or death. Because of the likelihood that the results obtained in this preliminary acute toxicity test have a direct relevance for protecting human health with respect to the use of AbAEE as a functional food or nutraceutial, an additional upper dose level of 5000 mg/kg b.wt. was used. Since no death was observed, the LD50 could not be estimated but is expected to exceed 5000 mg/kg and this extract could be classified as hazard category 5 (in Globally Harmonized Classification System for Chemical Substances and Mixtures.) or even unclassified for its acute toxicity by the oral route. The sub-chronic oral toxicity study of AbAEE (250 and 500 mg/kg b.wt. day) did not induce significant alterations in almost all hematological and biochemical parameters in rats. Therefore, the overall results of the present study provide supportive data on the use of AbAEE and provide a promising first step for their use as component of new functional foods or as nutraceutical. Though, further studies in both, animals and humans are needed for better evaluation of the food safety of this extract.Ministerio de Economía y Competitividad (MINECO). España IPT- 2011-1418-060000FEDER IPT- 2011-1418-06000

    Dielectric behaviour of Hf-doped CaCu3Ti4O12 ceramics obtained by conventional synthesis and reactive sintering

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    CaCu3(Ti4xHfx)O12 ceramics (JC = 0.04, 0.1 and 0.2) were prepared by conventional synthesis (CS) and through reactive sintering (RS), in which synthesis and sintering of the material take place in one single step. The microstructure and the dielectric properties of Hf-doped CCTO (CCTOHf) have been studied by XRD, FE-SEM, AFM, Raman and impedance spectroscopy (IS) in order to correlate the structure, microstructure and the electrical properties. Samples prepared by reactive sintering show slightly higher dielectric constant than those prepared by conventional synthesis in the same way than the pure CCTO. Dielectric constant and dielectric losses decrease slightly increasing Hf content. For CCTOHf ceramics with x> 0.04 for CS and x> 0.1 for RS, a secondary phase HfTi04 appears. As expected, the reactive sintering processing method allows a higher incorporation of Hf in the CCTO lattice than the conventional synthesis one

    Diminished neurogenic femoral artery vasoconstrictor response in a Zucker obese rat model: differential regulation of NOS and COX derivatives

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    Objective: Peripheral arterial disease is one of the macrovascular complications of type 2 diabetes mellitus. This study addresses femoral artery regulation in a prediabetic model of obese Zucker rats (OZR) by examining cross-talk between endothelial and neural factors. Methods and Results: Arterial preparations from lean (LZR) and OZR were subjected to electrical field stimulation (EFS) on basal tone. Nitric oxide synthase (NOS) and cyclooxygenase (COX) isoform expression patterns were determined by immunohistochemical labelling and Western blotting. Results indicate significantly reduced noradrenergic contractions in preparations from OZR compared with those of LZR. Functional inhibition of endothelial NOS (eNOS) indicated a predominant role of this isoform in LZR and its modified activity in OZR. Neural (nNOS) and inducible NOS (iNOS) were activated and their expression was higher in femoral arteries from OZR. Neurotransmission modulated by largeconductance Ca2+-activated (BKCa) or voltage-dependent (KV) K+ channels did not seem compromised in the obese animals. Endothelial COX-1 and COX-2 were expressed in LZR and an additional adventitial location of COX-2 was also observed in OZR, explaining the higher COX-2 protein levels detected in this group. Prostanoids derived from both isoforms helped maintain vasoconstriction in LZR while in OZR only COX-2 was active. Superoxide anion inhibition reduced contractions in endothelium-intact arteries from OZR. Conclusions: Endothelial dysfunction led to reduced neurogenic vasoconstriction in femoral arteries from OZR. In a setting of obesity, NO-dependent nNOS and iNOS dilation activity could be an alternative mechanism to offset COX-2- and reactive oxygen species-mediated vasoconstriction, along with impaired endothelial NO relaxation

    Self-perception of leadership styles and behaviour in primary health care

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    Background: The concept of leadership has been studied in various disciplines and from different theoretical approaches. It is a dynamic concept that evolves over time. There are few studies in our field on managers' self-perception of their leadership style. There are no pure styles, but one or another style is generally favoured to a greater or lesser degree. In the primary health care (PHC) setting, managers' leadership style is defined as a set of attitudes, behaviours, beliefs and values. The objectives of this study were to describe and learn about the self-perception of behaviours and leadership styles among PHC managers; to determine the influence of the leadership style on job satisfaction, efficiency, and willingness to work in a team; and to determine the relationship between transformational and transactional styles according age, gender, profession, type of manager years of management experience, and the type of organization. Methods: To describe leadership styles as perceived by PHC managers, a cross sectional study was performed using an 82 items-self-administered Multifactor Leadership Questionnaire (MLQ). This questionnaire measures leadership styles, attitudes and behaviour of managers. The items are grouped into three first order variables (transformational, transactional and laissez-faire) and ten second order variables (which discriminate leader behaviours). Additionally, the questionnaire evaluates organizational consequences such as extra-effort, efficiency and satisfaction. Results: One hundred forty responses from 258 managers of 133 PHC teams in the Barcelona Health Area (response rate: 54.26%). Most participants were nurses (61.4%), average age was 49 years and the gender predominantly female (75%). Globally, managers assessed themselves as equally transactional and transformational leaders (average: 3.30 points). Grouped by profession, nurses (28.57% of participants) showed a higher transactional leadership style, over transformational leadership style, compared to physicians (3.38 points, p < 0.003). Considering gender, men obtained the lowest results in transactional style (p < 0.015). Both transactional and transformational styles correlate with efficiency and job satisfaction (r = 0.724 and r = 0.710, respectively). Conclusions: PHC managers' self-perception of their leadership style was transactional, focused on the maintenance of the status quo, although there was a trend in some scores towards the transformational style, mainly among nurse managers. Both styles correlate with satisfaction and willingness to strive to work better. Keywords: Leadership, Primary health care, Self-concept, Job satisfaction, MLQ, Manager

    Dielectric behaviour of Hf-doped CaCu₃Ti₄O₁₂ ceramics obtained by conventional synthesis and reactive sintering

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    CaCu₃ (Ti₄₋ₓ Hfₓ )O₁₂ ceramics ( x  = 0.04, 0.1 and 0.2) were prepared by conventional synthesis (CS) and through reactive sintering (RS), in which synthesis and sintering of the material take place in one single step. The microstructure and the dielectric properties of Hf-doped CCTO (CCTOHf) have been studied by XRD, FE-SEM, AFM, Raman and impedance spectroscopy (IS) in order to correlate the structure, microstructure and the electrical properties. Samples prepared by reactive sintering show slightly higher dielectric constant than those prepared by conventional synthesis in the same way than the pure CCTO. Dielectric constant and dielectric losses decrease slightly increasing Hf content. For CCTOHf ceramics with x  > 0.04 for CS and x  > 0.1 for RS, a secondary phase HfTiO₄ appears. As expected, the reactive sintering processing method allows a higher incorporation of Hf in the CCTO lattice than the conventional synthesis one.Facultad de Ciencias Exacta

    Implication of type 4 NADPH oxidase (NOX4) in tauopathy.

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    Aggregates of the microtubule-associated protein tau are a common marker of neurodegenerative diseases collectively termed as tauopathies, such as Alzheimer’s disease (AD) and frontotemporal dementia. Therapeutic strategies based on tau have failed in late stage clinical trials, suggesting that tauopathy may be the consequence of upstream causal mechanisms. As increasing levels of reactive oxygen species (ROS) may trigger protein aggregation or modulate protein degradation and, we had previously shown that the ROS producing enzyme NADPH oxidase 4 (NOX4) is a major contributor to cellular autotoxicity, this study was designed to evaluate if NOX4 is implicated in tauopathy. Our results show that NOX4 is upregulated in patients with frontotemporal lobar degeneration and AD patients and, in a humanized mouse model of tauopathy induced by AVV-TauP301L brain delivery. Both, global knockout and neuronal knockdown of the Nox4 gene in mice, diminished the accumulation of pathological tau and positively modified established tauopathy by a mechanism that implicates modulation of the autophagy-lysosomal pathway (ALP) and, consequently, improving the macroautophagy flux. Moreover, neuronal-targeted NOX4 knockdown was sufficient to reduce neurotoxicity and prevent cognitive decline, even after induction of tauopathy, suggesting a direct and causal role for neuronal NOX4 in tauopathy. Thus, NOX4 is a previously unrecognized causative, mechanism-based target in tauopathies and blood-brain barrier permeable specific NOX4 inhibitors could have therapeutic potential even in established disease.post-print5895 K

    Resolución estructural en 3D de electrocerámicas mediante microscopía Raman confocal

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    Las propiedades de los materiales cerámicos son una combinación entre las propiedades intrínsecas, definidas por los granos cristalinos, y las propiedades extrínsecas, como son bordes de grano y fases secundarias. La relación entre estos dos elementos produce en muchas ocasiones, la presencia de propiedades inusuales que son la base de muchos materiales electrocerámicos. Sirvan como ejemplo algunos materiales tipo como son: varistores cerámicos, termistores, materiales con coeficiente de resistividad positivo, sensores de borde de grano, etc. En un material electrocerámico con respuesta funcional la correlación entre estructura-microestructura -propiedades es una constante, tanto en la etapa de diseño en laboratorio como en la etapa de producción industrial. El empleo de Microscopía Raman Confocal (MRC) se propone como una metodología relevante para el estudio de los factores que afectan a dichas correlaciones en materiales electrocerámicos. La técnica de MRC constituye una potente herramienta que permite determinar no solo la estructura sino las interacciones entre los elementos microestructurales. La correlación entre estas variables con las propiedades funcionales y la posibilidad de determinar las mismas en condiciones de operación, abren unas posibilidades que hasta la fecha solo estaban en la imaginación de los científicos. En esta presentación se resumen brevemente algunos de los principios relacionados con la técnica de Microscopía Raman Confocal, que junto con ejemplos seleccionados permiten visualizar aspectos relacionados con: la orientación de cristales, identificación fases cristalinas; resolución de nanoestructuras e interfases; determinación y dinámica de dominios ferroeléctricos; presencia de tensiones mecánicas; fenómenos de conducción,... sobre diferentes materiales cerámicos. Los trabajos mostrados son ejemplos de alta resolución en 3D de materiales funcionales como son los materiales electrocerámicos
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