707 research outputs found

    Interactions of mitochondrial and skeletal muscle biology in mitochondrial myopathy

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    \ua9 2023 The Author(s). Mitochondrial dysfunction in skeletal muscle fibres occurs with both healthy aging and a range of neuromuscular diseases. The impact of mitochondrial dysfunction in skeletal muscle and the way muscle fibres adapt to this dysfunction is important to understand disease mechanisms and to develop therapeutic interventions. Furthermore, interactions between mitochondrial dysfunction and skeletal muscle biology, in mitochondrial myopathy, likely have important implications for normal muscle function and physiology. In this review, we will try to give an overview of what is known to date about these interactions including metabolic remodelling, mitochondrial morphology, mitochondrial turnover, cellular processes and muscle cell structure and function. Each of these topics is at a different stage of understanding, with some being well researched and understood, and others in their infancy. Furthermore, some of what we know comes from disease models. Whilst some findings are confirmed in humans, where this is not yet the case, we must be cautious in interpreting findings in the context of human muscle and disease. Here, our goal is to discuss what is known, highlight what is unknown and give a perspective on the future direction of research in this area

    Nailfold Capillaroscopy and Autoimmune Connective Tissue Diseases in Patients From a Portuguese Nailfold Capillaroscopy Clinic

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    Raynaud's phenomenon (RP) is frequent in autoimmune connective tissue diseases (AICTD) and its approach includes nailfold capillaroscopy (NFC), as it is a non-invasive technique that permits direct visualization of the microcirculation. The aim of this study is to analyze and establish clinical correlations between NFC findings and particular aspects of autoimmune disorders. This is a retrospective study. Clinical data from patients attending our NFC clinic were reviewed. Inclusion criteria included AICTD previous diagnosis, which included systemic sclerosis (SSc), mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE), Sjögren syndrome, inflammatory idiopathic myopathies (IIM), rheumatoid arthritis, undifferentiated connective tissue disease and antiphospholipid syndrome (APS). Videocap® version 3.0 biomicroscope was used. NFC score was determined. For statistics, SPSS software was utilized. 384 patients were included; most of them were women, with mean age of 47 years. RP was present in 91% of the patients, with greater prevalence in SSc and MCTD. Scleroderma pattern was the most prevalent NFC pattern, mainly in SSc, MCTD and IIM. Mean capillary density was reduced in IIM, SSc and MCTD. NFC score was worse in SSc, IIM and MCTD. In patients with AICTD, RP is related to microvascular damage and worse NFC score. NFC scleroderma pattern correlates with SSc classification criteria score. In MCTD, scleroderma pattern relates to myositis. SLE and APS reveal significant hemorrhages, but not related to APS antibodies. This study highlights the possible role of NFC as biomarker of AICTD, particularly in SSc and IIM.info:eu-repo/semantics/publishedVersio

    Snow metamorphism: a fractal approach

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    Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

    Neuropeptide Y inhibits interleukin-1β-induced phagocytosis by microglial cells

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    <p>Abstract</p> <p>Background</p> <p>Neuropeptide Y (NPY) is emerging as a modulator of communication between the brain and the immune system. However, in spite of increasing evidence that supports a role for NPY in the modulation of microglial cell responses to inflammatory conditions, there is no consistent information regarding the action of NPY on microglial phagocytic activity, a vital component of the inflammatory response in brain injury. Taking this into consideration, we sought to assess a potential new role for NPY as a modulator of phagocytosis by microglial cells.</p> <p>Methods</p> <p>The N9 murine microglial cell line was used to evaluate the role of NPY in phagocytosis. For that purpose, an IgG-opsonized latex bead assay was performed in the presence of lipopolysaccharide (LPS) and an interleukin-1β (IL-1β) challenge, and upon NPY treatment. A pharmacological approach using NPY receptor agonists and antagonists followed to uncover which NPY receptor was involved. Moreover, western blotting and immunocytochemical studies were performed to evaluate expression of p38 mitogen-activated protein kinase (MAPK) and heat shock protein 27 (HSP27), in an inflammatory context, upon NPY treatment.</p> <p>Results</p> <p>Here, we show that NPY inhibits phagocytosis of opsonized latex beads and inhibits actin cytoskeleton reorganization triggered by LPS stimulation. Co-stimulation of microglia with LPS and adenosine triphosphate also resulted in increased phagocytosis, an effect inhibited by an interleukin-1 receptor antagonist, suggesting involvement of IL-1β signaling. Furthermore, direct application of LPS or IL-1β activated downstream signaling molecules, including p38 MAPK and HSP27, and these effects were inhibited by NPY. Moreover, we also observed that the inhibitory effect of NPY on phagocytosis was mediated <it>via </it>Y<sub>1 </sub>receptor activation.</p> <p>Conclusions</p> <p>Altogether, we have identified a novel role for NPY in the regulation of microglial phagocytic properties, in an inflammatory context.</p

    Caracterização de linhagens de sorgo granífero [Sorghum bicolor (L.) Moench] para tolerância ao alumínio.

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    Com o avanço do cultivo de sorgo no cerrado brasileiro observa-se a crescente necessidade do estudo e seleção de genótipos mais tolerantes às condições desta região, que se caracteriza por apresentar solos e subsolos com baixo pH e alumínio solúvel em níveis tóxicos. Para tanto, técnicas de melhoramento genético vêm sendo empregadas na tentativa de solucionar ou minimizar os efeitos dessas condições sobre o desenvolvimento das culturas. Este ensaio teve como finalidade caracterizar oito linhagens de sorgo granífero contrastantes para a tolerância ao alumínio tóxico, que foram desenvolvidas para servirem como ferramentas na avaliação de tolerância ao Al no campo. Estas linhagens possibilitarão a criação de híbridos isogênicos com zero, um ou dois alelos para a tolerância ao Al tóxico. A caracterização destas linhagens foi realizada em solução nutritiva na Embrapa Milho e Sorgo, em Sete Lagoas/MG e todas as análises estatísticas foram realizadas utilizando-se o programa Genes

    Combining ability of grain sorghum lines selected for aluminum tolerance.

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    The purpose of this study was to estimate combining ability of 58 sorghum lines previously selected for Aluminum (Al) tolerance. One hundred sixty-five hybrids were evaluated at three levels of Al saturation (0%, 20% and 50%) at the same season. General Combining Ability (GCA) effects were significant for female lines for all three traits. GCA effects for male lines were significant only for plant height. Specific Combining Ability (SCA) effects were significant only for flowering time. The ratio GCA to SCA was greater than the unity, indicating the prevalence of additive effects for the control of Al tolerance. F7, F14, F17, F20, F21, F24, F29, F31, F41, F42, F48, F51, F54 and F55 lines contributed to increase yield, while F29, F48 and F51 also contributed to reduce flowering time. M2 was the best male line since it contributed to increase yield and plant height, and to reduce flowering time
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