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Search Results: 1 - 10 of 121211 matches for " Jo?o O. Malva "
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Can we talk about microglia without neurons? A discussion of microglial cell autonomous properties in culture
Ismael Neiva,Joo O. Malva,Jorge Valero
Frontiers in Cellular Neuroscience , 2014, DOI: 10.3389/fncel.2014.00202
Brain-Derived Neurotrophic Factor Promotes Vasculature-Associated Migration of Neuronal Precursors toward the Ischemic Striatum
Sofia Grade, Yuan C. Weng, Marina Snapyan, Jasna Kriz, Joo O. Malva, Armen Saghatelyan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0055039
Abstract: Stroke induces the recruitment of neuronal precursors from the subventricular zone (SVZ) into the ischemic striatum. In injured areas, de-routed neuroblasts use blood vessels as a physical scaffold to their migration, in a process that resembles the constitutive migration seen in the rostral migratory stream (RMS). The molecular mechanism underlying injury-induced vasculature-mediated migration of neuroblasts in the post-stroke striatum remains, however, elusive. Using adult mice we now demonstrate that endothelial cells in the ischemic striatum produce brain-derived neurotrophic factor (BDNF), a neurotrophin that promotes the vasculature-mediated migration of neuronal precursors in the RMS, and that recruited neuroblasts maintain expression of p75NTR, a low-affinity receptor for BDNF. Reactive astrocytes, which are widespread throughout the damaged area, ensheath blood vessels and express TrkB, a high-affinity receptor for BDNF. Despite the absence of BDNF mRNA, we observed strong BDNF immunolabeling in astrocytes, suggesting that these glial cells trap extracellular BDNF. Importantly, this pattern of expression is reminiscent of the adult RMS, where TrkB-expressing astrocytes bind and sequester vasculature-derived BDNF, leading to the entry of migrating cells into the stationary phase. Real-time imaging of cell migration in acute brain slices revealed a direct role for BDNF in promoting the migration of neuroblasts to ischemic areas. We also demonstrated that cells migrating in the ischemic striatum display higher exploratory behavior and longer stationary periods than cells migrating in the RMS. Our findings suggest that the mechanisms involved in the injury-induced vasculature-mediated migration of neuroblasts recapitulate, at least partially, those observed during constitutive migration in the RMS.
New insights into the role of histamine in subventricular zone-olfactory bulb neurogenesis
Maria F. Eiriz,Jorge Valero,Joo O. Malva,Liliana Bernardino
Frontiers in Neuroscience , 2014, DOI: 10.3389/fnins.2014.00142
Abstract: The subventricular zone (SVZ) contains neural stem cells (NSCs) that generate new neurons throughout life. Many brain diseases stimulate NSCs proliferation, neuronal differentiation and homing of these newborns cells into damaged regions. However, complete cell replacement has never been fully achieved. Hence, the identification of proneurogenic factors crucial for stem cell-based therapies will have an impact in brain repair. Histamine, a neurotransmitter and immune mediator, has been recently described to modulate proliferation and commitment of NSCs. Histamine levels are increased in the brain parenchyma and at the cerebrospinal fluid (CSF) upon inflammation and brain injury, thus being able to modulate neurogenesis. Herein, we add new data showing that in vivo administration of histamine in the lateral ventricles has a potent proneurogenic effect, increasing the production of new neuroblasts in the SVZ that ultimately reach the olfactory bulb (OB). This report emphasizes the multidimensional effects of histamine in the modulation of NSCs dynamics and sheds light into the promising therapeutic role of histamine for brain regenerative medicine.
Neuropeptide Y inhibits interleukin-1β-induced phagocytosis by microglial cells
Raquel Ferreira, Tiago Santos, Michelle Viegas, Luísa Cortes, Liliana Bernardino, Otília V Vieira, Joo O Malva
Journal of Neuroinflammation , 2011, DOI: 10.1186/1742-2094-8-169
Abstract: 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.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 via Y1 receptor activation.Altogether, we have identified a novel role for NPY in the regulation of microglial phagocytic properties, in an inflammatory context.Microglia are the resident immunocompetent cells of the central nervous system (CNS), responsible for mounting appropriate responses to injuries such as trauma, ischemia, brain tumors and neurodegenerative diseases that target the brain parenchyma [1,2]. Moreover, microglia display a wide range of receptors that enable the recognition of pathogens or cell damage-related antigens, thereby promoting phagocytosis and removal of cell debris [3]. Phagocytosis is a coordinated process, triggered by environmental signals that requires a dynamic actin cytoskeleton rearrangement and a plethora of receptor signaling pathw
Activation of Type 1 Cannabinoid Receptor (CB1R) Promotes Neurogenesis in Murine Subventricular Zone Cell Cultures
Sara Xapelli, Fabienne Agasse, Laura Sardà-Arroyo, Liliana Bernardino, Tiago Santos, Filipa F. Ribeiro, Jorge Valero, José Bragan?a, Clarissa Schitine, Ricardo A. de Melo Reis, Ana M. Sebasti?o, Joo O. Malva
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063529
Abstract: The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+]i) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.
Modulation of subventricular zone oligodendrogenesis: a role for hemopressin?
Sara Xapelli,Fabienne Agasse,Sofia Grade,Liliana Bernardino,Filipa F. Ribeiro,Clarissa S. Schitine,Andrea S. Heimann,Emer S. Ferro,Ana M. Sebasti?o,Ricardo A. De Melo Reis,Joo O. Malva
Frontiers in Cellular Neuroscience , 2014, DOI: 10.3389/fncel.2014.00059
Abstract: Neural stem cells (NSCs) from the subventricular zone (SVZ) have been indicated as a source of new oligodendrocytes to use in regenerative medicine for myelin pathologies. Indeed, NSCs are multipotent cells that can self-renew and differentiate into all neural cell types of the central nervous system. In normal conditions, SVZ cells are poorly oligodendrogenic, nevertheless their oligodendrogenic potential is boosted following demyelination. Importantly, progressive restriction into the oligodendrocyte fate is specified by extrinsic and intrinsic factors, endocannabinoids being one of these factors. Although a role for endocannabinoids in oligodendrogenesis has already been foreseen, selective agonists and antagonists of cannabinoids receptors produce severe adverse side effects. Herein, we show that hemopressin (Hp), a modulator of CB1 receptors, increased oligodendroglial differentiation in SVZ neural stem/progenitor cell cultures derived from neonatal mice. The original results presented in this work suggest that Hp and derivates may be of potential interest for the development of future strategies to treat demyelinating diseases.
Fernández Ruiz,José Manuel; Olavarría Avenda?o,Malva;
Ius et Praxis , 2009, DOI: 10.4067/S0718-00122009000200008
Abstract: the article analyzes the wrongful conviction claim, primarily the provision letter d) article 473 of the chilean code of criminal procedure. on the basis of a conceptual study concerning the current legal regulation, and a empirical study in light of the application of the provision discussed, the authors account for two general kinds of problems: of legislative design and judicial interpretation. it stresses the need to properly differentiate the requirements of the wrongful conviction procedure, proposing an interpretation that should be deemed correct.
José Manuel Fernández Ruiz,Malva Olavarría Avenda?o
Ius et Praxis (En línea) , 2009,
Abstract: El artículo analiza la revisión de las sentencias condenatorias firmes, restringiéndose principalmente a la causal letra d) del artículo 473 del Código Procesal Penal. Sobre la base tanto de un estudio conceptual relativo a la regulación legal vigente, como empírico a la luz de la aplicación de la disposición que se comenta, los autores dan cuenta de dos tipos generales de problemas: de dise o legislativo y de interpretación jurisprudencial. Se destaca la necesidad de diferenciar adecuadamente los requisitos que hacen procedente la acción de revisión, proponiéndose cual debe ser la interpretación correcta. The article analyzes the wrongful conviction claim, primarily the provision letter d) article 473 of the Chilean Code of Criminal Procedure. On the basis of a conceptual study concerning the current legal regulation, and a empirical study in light of the application of the provision discussed, the authors account for two general kinds of problems: of legislative design and judicial interpretation. It stresses the need to properly differentiate the requirements of the wrongful conviction procedure, proposing an interpretation that should be deemed correct.
Application of a Computational Tool to Study the Influence of Worn Wheels on Railway Vehicle Dynamics  [PDF]
Joo Pombo
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.52009
Abstract: The search for fast, reliable and cost effective means of transport that presents better energy efficiency and less impact on the environment has resulted in renewed interest and rapid development in railway technology. To improve its efficiency and competitiveness, modern trains are required to travel faster, with high levels of safety and comfort and with reduced Life Cycle Costs (LCC). These increasing demands for vehicle requirements imposed by railway operators and infrastructure companies include maintaining the top operational speeds of trainsets during their life cycle, having low LCC and being track friendly. This is a key issue in vehicle design and in train operation since it has a significant impact on the safety and comfort of railway systems and on the maintenance costs of vehicles and infrastructures. The purpose of this work is to analyze how the wear progression on the wheelsets affects the dynamic behavior of railways vehicles and its interaction with the track. For this purpose a vehicle, assembled with new and worn wheels, is studied in realistic operation scenarios. The influence of the wheel profile wear on the vehicle dynamic response is assessed here based on several indicators used by the railway industry. The running stability of the railway vehicles is also emphasized in this study.
Nutritional Quality and Health Benefits of Vegetables: A Review  [PDF]
Joo Silva Dias
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.310179
Abstract: Vegetables are considered essential for well-balanced diets since they supply vitamins, minerals, dietary fiber, and phytochemicals. Each vegetable group contains an unique combination and amount of these phytonutriceuticals, which distinguishes them from other groups and vegetables whithin their own group. In the daily diet vegetables have been strongly associated with improvement of gastrointestinal health, good vision, and reduced risk of heart disease, stroke, chronic diseases such as diabetes, and some forms of cancer. Some phytochemicals of vegetables are strong antioxidants and are thought to reduce the risk of chronic disease by protecting against free radical damage, by modifying metabolic activation and detoxification of carcinogens, or even by influencing processes that alter the course of tumor cells. All the vegetables may offer protection to humans against chronic diseases. Nutrition is both a quantity and a quality issue, and vegetables in all their many forms ensure an adequate intake of most vitamins and nutrients, dietary fibers, and phytochemicals which can bring a much-needed measure of balance back to diets contributing to solve many of these nutrition problems. The promotion of healthy vegetable products has coincided with a surging consumer interested in the healthy functionality of food. Because each vegetable contains a unique combination of phytonutriceuticals, a great diversity of vegetables should be eaten to ensure that individual’s diet includes a combination of phytonutriceuticals and to get all the health benefits. This article make a review and discusses the nutritional quality and health benefits of the major groups of vegetables. More interdisciplinary work is required that involves nutritional and food scientists as well as others from biomedical fields to ascertain the thrue function of specific phytonutriceuticals.
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