268 research outputs found
Estrogen protection in Parkinson´s disease – a GDNF role?
Estrogen protection in Parkinson´s disease – a GDNF role
Quantification and Localization of Intracellular Free Mg2+ in Bovine Chromaffin Cells
Magnesium is an essential element for all living systems. The quantification of free intracellular Mg2+ concentration ([Mg2+]i) is of utmost importance since changes in its basal value may be an indication of
different pathologies due to abnormalities of Mg2+ metabolism. In this work we used 31P NMR and
fluorescence spectroscopy to determine the resting [Mg2+]i in bovine chromaffin cells, a neuron-like cellular
model, as well as confocal laser scanning microscopy to study the free Mg2+ spatial distribution in these cells.
31P NMR spectroscopy did not prove to be effective for the determination of [Mg2+]i in this particular case due to some special morphological and physiological properties of this cell type. A basal [Mg2+]i value of
0.551 ± 0.008 mM was found for these cells using fluorescence spectroscopy and the Mg2+-sensitive probe
furaptra; this value falls in the concentration range reported in the literature for neurons from different
sources. This technique proved to be an accurate and sensitive tool to determine the [Mg2+]i
Characterization of self-assembled thiols monolayers on gold surface by electrochemical impedance spectroscopy
Thiols with different alkyl chain length and containing COOH terminal group were self-assembled on gold electrodes. The electron transfer of Fe(CN)6(3-/4-) couple to the electrode was studied at different pH by means cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Changes in solution pH resulted in the charge variation of the self-assembled monolayer (SAM) terminal group and, consequently, the electrostatic interaction of SAM with the electroactive species in the solution.Tióis de cadeias carbônicas com tamanhos diferentes e contendo grupo terminal COOH foram usados para formar monocamadas auto-organizadas sobre a superfÃcie de eletrodos de ouro. A transferência de elétrons do par Fe(CN)6(3-/4-) para o eletrodo foi estudada em diferentes pH usando-se as técnicas de voltametria cÃclica (CV) e de espectroscopia de impedância eletroquÃmica (EIS). Mudanças no pH da solução resultaram em variações na carga do grupo terminal das monocamadas auto-organizadas e, conseqüentemente, em alterações na interação eletrostática da SAM com as espécies eletroativas em solução.849855Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES
Initiation paths to the research of future graduates in educational sciences: participation experiences in the project "Global Citizenship Education"
Li+ Influx and Binding, and Li+/Mg2+ Competition in Bovine Chromaffin Cell Suspensions as Studied by 7Li NMR and Fluorescence Spectroscopy
Li+ influx by bovine chromaffin cells, obtained from bovine adrenal medulla, was studied in intact cell suspensions using 7Li NMR spectroscopy with the shift reagent [Tm(HDOTP)]4-. The influx rate constants, ki, were determined in the absence and in the presence of two Na+ membrane transport inhibitors. The values obtained indicate that both voltage sensitive Na+ channels and (Na+/K+)-ATPase play an important role in Li+ uptake by these cells. 7Li NMR T1 and T2 relaxation times for intracellular Li+ in bovine chromaffin cells provided a T1/T2 ratio of 305, showing that Li+ is highly, immobilized due to strong binding to intracellular structures. Using fluorescence spectroscopy and the Mg2+ fluorescent probe, furaptra, the free intracellular Mg2+ concentration in the bovine chromaffin cells incubated with 15 mM LiCl was found to increase by about mM after the intracellular Li+ concentration reached a steady state. Therefore, once inside the cell, Li+ is able to displace Mg2+ from its binding sites
Optimal control of the COVID-19 pandemic: controlled sanitary deconfinement in Portugal
The COVID-19 pandemic has forced policy makers to decree urgent confinements
to stop a rapid and massive contagion. However, after that stage, societies are
being forced to find an equilibrium between the need to reduce contagion rates
and the need to reopen their economies. The experience hitherto lived has
provided data on the evolution of the pandemic, in particular the population
dynamics as a result of the public health measures enacted. This allows the
formulation of forecasting mathematical models to anticipate the consequences
of political decisions. Here we propose a model to do so and apply it to the
case of Portugal. With a mathematical deterministic model, described by a
system of ordinary differential equations, we fit the real evolution of
COVID-19 in this country. After identification of the population readiness to
follow social restrictions, by analyzing the social media, we incorporate this
effect in a version of the model that allow us to check different scenarios.
This is realized by considering a Monte Carlo discrete version of the previous
model coupled via a complex network. Then, we apply optimal control theory to
maximize the number of people returning to "normal life" and minimizing the
number of active infected individuals with minimal economical costs while
warranting a low level of hospitalizations. This work allows testing various
scenarios of pandemic management (closure of sectors of the economy,
partial/total compliance with protection measures by citizens, number of beds
in intensive care units, etc.), ensuring the responsiveness of the health
system, thus being a public health decision support tool.publishe
Estudo hidrogeológico de uma área montanhosa (Serra da Estrela,Portugal central): uma abordagem multidisciplinar
The results ofa preliminary hydrogeological study ofthe river Zêzere catchment upstream ofManteigas(Serra da Estrela Natural Park,Central Portugal) are presented.In this mountain region,different types of groundwater and surface water (used in several economic activities) occur.The methodology adopted in thisstudy emphasizes the way how Geology,Geomorphology,Geophysics,Geochemistry,Soil Science andHydrogeology contribute to the description ofthe hydrological phenomena taking place in the catchment,such as infiltration and aquifer recharge and groundwater flow and geochemistry — allowing to develop bet-ter hydrogeologic conceptual models.The hydrological modelling in course includes the use ofthe VISU- AL BALAN code,which is being coupled to a GIS.The hydrogeochemical techniques are highlighted as well as its preliminary results concerning major and minor elements.The thermomineral water study includes the identification ofthe reservoir’s geologic material,the characterization ofwater-rock interactionand geothermometry.info:eu-repo/semantics/publishedVersio
BDNF/TrkB/Akt signaling pathway epithelial odontogenic tumors and keratocyst : an immunohistochemical study comparative with dental germs
Odontogenic lesions (OL) are an important group of oral and maxillofacial diseases represented by odontogenic cysts, benign, and malignant tumors. The brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling pathway has multiple biological actions and has been identified as an important pathway in the proliferation, invasion, and survival of different epithelial tumors. Its role in the development of OL, however, has so far been unexplored. Our aim was to evaluate the BDNF/TrkB/Akt/p-RPS6 signaling pathway in OL of epithelial origin. This cross-sectional study comprised 3 cases of tooth germs, 25 cases of odontogenic keratocyst (OK), 29 cases of ameloblastoma (Am), and 6 cases of ameloblastic carcinoma. Immunohistochemical staining for BDNF, TrkB, p-Akt, and p-RPS6 was performed. OLs were evaluated according to the pattern of immunohistochemical expression in epithelial cells and by semiquantitative scores that considered the intensity of staining and percentage of positive cells. BDNF stromal expression was also assessed. No significant differences were observed with respect to the percentage of positive cases for all markers. Regarding the immunoreactive scores, BDNF and p-RPS6 expressions were similar in the odontogenic epithelium of all OL. However, TrkB and p-Akt were overexpressed in OK compared with ameloblastic carcinoma. In Am, epithelial BDNF was significantly higher compared with stromal expression. In conclusion, BDNF seems to participate in the development of cystic, benign, and malignant odontogenic epithelium to similar degrees. The acquisition of the invasive or malignant phenotype in odontogenic neoplasms is not associated with alterations in the BDNF/TrkB/Akt/RPS6 axis, which could be implicated in the differentiation process.The São Paulo State Research Foundationhttp://www.appliedimmunohist.comhj2022Oral Pathology and Oral Biolog
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