CD133, CD15/SSEA-1, CD34 or side populations do not resume tumor-initiating properties of long-term cultured cancer stem cells from human malignant glio-neuronal tumors

<p>Abstract</p> <p>Background</p> <p>Tumor initiating cells (TICs) provide a new paradigm for developing original therapeutic strategies.</p> <p>Methods</p> <p>We screened for TICs in 47 human adult brain malignant tumors. Cells forming floating spheres in culture, and endowed with all of the features expected from tumor cells with stem-like properties were obtained from glioblastomas, medulloblastoma but not oligodendrogliomas.</p> <p>Results</p> <p>A long-term self-renewal capacity was particularly observed for cells of malignant glio-neuronal tumors (MGNTs). Cell sorting, karyotyping and proteomic analysis demonstrated cell stability throughout prolonged passages. Xenografts of fewer than 500 cells in Nude mouse brains induced a progressively growing tumor. CD133, CD15/LeX/Ssea-1, CD34 expressions, or exclusion of Hoechst dye occurred in subsets of cells forming spheres, but was not predictive of their capacity to form secondary spheres or tumors, or to resist high doses of temozolomide.</p> <p>Conclusions</p> <p>Our results further highlight the specificity of a subset of high-grade gliomas, MGNT. TICs derived from these tumors represent a new tool to screen for innovative therapies.</p

Effect of the competition of Cu(II) and Ni(II) on the kinetic and thermodynamic stabilities of Cr(III)-organic ligand complexes using competitive ligand exchange (EDTA)

The effect of competition of Cu(II) and Ni(II) on the kinetic stability of Cr(III) complexed with natural organic matter (NOM) was characterized using EDTA exchange with single-stage tangential-flow ultrafiltration. For a water sample from Serra de Itabaiana, 3% of spiked Cr(III) was exchanged, while for a sample from the Itapanhau River, 7, 10, 10, and 21% was exchanged in experiments using Cr(III) alone and in combination with Cu(ll), NOD, or Cu(II) + Ni(II), respectively. Times required to reach exchange equilibrium with EDTA were less than 360 min. The influence of competition from Ni(II) and Cu(II) on the availability of complexed Cr(III) was low, demonstrating preference of the ligand sites for Cr(III). This was correlated with sample humification, as confirmed by EPR and C-13 NMR analyses. Exchange efficiency was in the order Cu &gt; Ni &gt; Cr, and the process could be readily described by first order kinetics, with average rate constants of 0.35-0.37 11-1. (C) 2015 Elsevier Ltd. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Probabilistic design and reliability analysis of scour protections for offshore windfarms

Scour protection is an important component of fixed bottom foundations for offshore wind turbines. Depending on the hydrodynamic conditions, they might be indispensable to avoid the structural collapse of the foundation due to scour phenomena. The design of scour protections is typically deterministic, which often results in overestimated mean diameters of the armour layer. Moreover, the design methodologies currently applied do not provide a measure of safety associated with the proposed design. The present research proposes a novel methodology to assess the safety of the protection and to perform the probabilistic design of static and dynamic scour protections. A case study based on Horns Rev. 3 offshore wind farm is used to show how to select the mean stone diameter according to a pre-defined probability of failure of the protection. The results show that a dynamic scour protection could be safely designed with a reduction of the mean stone diameter up to 15 cm, when compared with the statically stable protection

Thermal Decomposition Kinetics of Humic Substances Extracted from Mid-Rio Negro (Amazon Basin) Soil Samples

In this work humic substances (HS) extracted from non-flooded (Araca) and flooded (Iara) soils were characterized through the calculation of stability and activation energies associated with the dehydration and thermal decomposition of HS using TGA and DTA, electronic paramagnetic resonance and C/H, C/N and C/O atomic ratios. For HS extracted from flooded soils, there was evidence for the influence of humidity on the organic matter humification process. Observations of thermal behaviour, with elemental analysis, indicated the presence of fossilized organic carbon within clay particles, which only decomposed above 800 C. This characteristic could explain the different thermal stability and pyrolysis activation energies for Iara HS compared to Araca HS.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Fractionation of asphaltenes in n-hexane and on adsorption onto CaCO3 and characterization by ESI(+)FT-ICR MS: Part I

Two methods of asphaltenes fractionation have been employed to facilitate the characterization of their respective subfractions. The methods are based on step-wise precipitation with different n-hexane/crude oil ratios, and on adsorption onto CaCO3. Three subfractions were produced for each method, being named of 3.5 V, 3.5-6 V, and 6-40 V (for the first method); and non-adsorbed (bulk), adsorbed, and irreversibly adsorbed (for the second method). The fractions were characterized by elementary analysis, nuclear magnetic resonance of proton (1H NMR) and by positive ion-mode electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI(+) FT-ICR MS). The elemental analysis, described in previous work, revealed that the C/H ratio for whole asphaltene and its sub-fractions varied between a narrow range (0.83-0.88) which means they present similar aromaticity or unsaturation. Furthermore, the elemental analysis corroborates with the 1H NMR analysis suggesting that subfraction 6-40 V presented a more aromatic profile than of remaining subfractions, while for the fractionation using CaCO3, this behavior was observed for the adsorbed subfraction. However, a more detailed molecular information was obtained from ESI(+)-FT-ICR MS data, showing that polar compounds species with lower carbon numbers were mainly found for the irreversibly adsorbed subfraction. Besides, the double bond equivalent (DBE) distribution is an important tool to associate the chemical information with solubility parameters, in which, a narrower DBE distribution was observed for irreversibly adsorbed (for fractionation onto CaCO3) and subfraction 3.5 V (fractionation in n-hexane) samples, indicating that they are less soluble in hydrocarbons. Also, solubility parameters (d) were calculated from ESI(+) FT-ICR MS data, where the results indicate that subfractions produced in n-hexane have a lower tendency to precipitate in hydrocarbons in relation to subfractions produced onto CaCO3210790802CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO AMAPÁ - FAPEAPFUNDAÇÃO DE AMPARO À PESQUISA E INOVAÇÃO DO ESPÍRITO SANTO - FAPESsem informação23038.007083/2014-40sem informaçãosem informaçã

Effect of thyroid hormone T3 on Myosin-Va expression in the central nervous system

Thyroid hormones (THs) are essential for brain development, where they regulate gliogenesis, myelination, cell proliferation and protein synthesis. Hypothyroidism severely affects neuronal growth and establishment of synaptic connections. Triiodothyronine (T3), the biologically active form of TH, has a central function in these activities. So, Myosin-Va (Myo-Va), a molecular motor protein involved in vesicle and RNA transport, is a good candidate as a target for T3 regulation. Here, we analyzed Myo-Va expression in euthyroid and hypothyroid adult rat brains and synaptosomes. We observed a reduction of Myo-Va expression in cultured neural cells from newborn hypothyroid rat brain, while immunocytochemical experiments showed a punctate distribution of this protein in the cytoplasm of cells. Particularly, Myo-Va co-localized with microtubules in neurites, especially in their varicosities. Myo-Va immunostaining was stronger in astrocytes and neurons of controls when compared with hypothyroid brains. In addition, supplementation of astrocyte cultures with T3 led to increased expression of Myo-Va in cells from both euthyroid and hypothyroid animals, suggesting that T3 modulates Myo-Va expression in neural cells both in vivo and in vitro. We have further analyzed Myo-Va expression in U373 cells, a human glioblastoma line, and found the same punctate cytoplasmic protein localization. As in normal neural cells, this expression was also increased by T3, suggesting that the modulatory mechanism exerted by T3 over Myo-Va remains active on astrocyte tumor cells. These data, coupled with the observation that Myo-Va is severely affected in hypothyroidism, support the hypothesis that T3 activity regulates neural motor protein expression, taking Myo-Va as a model. As a consequence, reduced T3 activity could supposedly affect axonal transport and synaptic function, and could therefore explain disturbances seen in the hypothyroid brain. (C) 2009 Elsevier B.V. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Derivation of functional human astrocytes from cerebral organoids

Astrocytes play a critical role in the development and homeostasis of the central nervous system (CNS). Astrocyte dysfunction results in several neurological and degenerative diseases. However, a major challenge to our understanding of astrocyte physiology and pathology is the restriction of studies to animal models, human post-mortem brain tissues, or samples obtained from invasive surgical procedures. Here, we report a protocol to generate human functional astrocytes from cerebral organoids derived from human pluripotent stem cells. The cellular isolation of cerebral organoids yielded cells that were morphologically and functionally like astrocytes. Immunolabelling and proteomic assays revealed that human organoid-derived astrocytes express the main astrocytic molecular markers, including glutamate transporters, specific enzymes and cytoskeletal proteins. We found that organoid-derived astrocytes strongly supported neuronal survival and neurite outgrowth and responded to ATP through transient calcium wave elevations, which are hallmarks of astrocyte physiology. Additionally, these astrocytes presented similar functional pathways to those isolated from adult human cortex by surgical procedures. This is the first study to provide proteomic and functional analyses of astrocytes isolated from human cerebral organoids. The isolation of these astrocytes holds great potential for the investigation of developmental and evolutionary features of the human brain and provides a useful approach to drug screening and neurodegenerative disease modelling7CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE APOIO À PESQUISA DO DISTRITO FEDERAL - FAPDFsem informaçãosem informaçãosem informaçãosem informação13/08711-3; 14/10068-4; 14/21035-0; 16/07332-