Clonal human fetal ventral mesencephalic dopaminergic neuron precursors for cell therapy research

A major challenge for further development of drug screening procedures, cell replacement therapies and developmental studies is the identification of expandable human stem cells able to generate the cell types needed. We have previously reported the generation of an immortalized polyclonal neural stem cell (NSC) line derived from the human fetal ventral mesencephalon (hVM1). This line has been biochemically, genetically, immunocytochemically and electrophysiologically characterized to document its usefulness as a model system for the generation of A9 dopaminergic neurons (DAn). Long-term in vivo transplantation studies in parkinsonian rats showed that the grafts do not mature evenly. We reasoned that diverse clones in the hVM1 line might have different abilities to differentiate. In the present study, we have analyzed 9 hVM1 clones selected on the basis of their TH generation potential and, based on the number of v-myc copies, v-myc down-regulation after in vitro differentiation, in vivo cell cycle exit, TH+ neuron generation and expression of a neuronal mature marker (hNSE), we selected two clones for further in vivo PD cell replacement studies. The conclusion is that homogeneity and clonality of characterized NSCs allow transplantation of cells with controlled properties, which should help in the design of long-term in vivo experimentsThis work was supported by grants from the Spanish Ministry of Economy and Competitiveness (formerly Science and Innovation; PLE2009-0101, SAF2010-17167), Comunidad Autónoma Madrid (S2011-BMD-2336), Instituto Salud Carlos III (RETICS TerCel, RD06/0010/0009) and European Union (Excell, NMP4-SL-2008-214706). This work was also supported by an institutional grant from Foundation Ramón Areces to the Center of Molecular Biology Severo Ocho

Nestin-GFP Transgene Reveals Neural Precursor Cells in Adult Skeletal Muscle

Background: Therapy for neural lesions or degenerative diseases relies mainly on finding transplantable active precursor cells. Identifying them in peripheral tissues accessible for biopsy, outside the central nervous system, would circumvent the serious immunological and ethical concerns impeding cell therapy. Methodology/Principal Findings: In this study, we isolated neural progenitor cells in cultured adult skeletal muscle from transgenic mice in which nestin regulatory elements control GFP expression. These cells also expressed the early neural marker Tuj1 and light and heavy neurofilament but not S100b, indicating that they express typical neural but not Schwann cell markers. GFP+/Tuj1+ cells were also negative for the endothelial and pericyte markers CD31 and a-smooth muscle actin, respectively. We established their a) functional response to glutamate in patch-clamp recordings; b) interstitial mesenchymal origin; c) replicative capacity; and d) the environment necessary for their survival after fluorescenceactivated cell sorting. Conclusions/Significance: We propose that the decline in nestin-GFP expression in muscle progenitor cells and its persistence in neural precursor cells in muscle cultures provide an invaluable tool for isolating a population of predifferentiated neural cells with therapeutic potential

Calculating the stress of multi-track formations in induction-assisted laser cladding

In laser cladding weld bead tracks, which are often made of wear and corrosion resistant materials, are strongly joined to the subjacent work piece forming surfaces as well as complex volume build-ups. The process is typically characterized by high laser-related temperature gradients and also density changes due to phase transformations arising during cooling. That results in high thermal stresses which even may lead to the formation of cracks in case of brittle materials. An optimized temperature distribution of the process zone which might be reached by optimized process conditions or by additional inductive heat sources can significantly reduce critical stresses and, hence, the danger of cracking. Additionally the stress formation can be strongly influenced by a suitable placement of neighboring weld beads. Stresses of multi-track formations are completely different compared to the stress distribution of a single weld bead. By means of a heuristic as well as a three-dimensional FEM-model the interaction between process parameters, tailored temperature distributions and the placement of tracks has been clarified. Especially the transition of metallographic cross-sections into numerical meshes enables realistic simulations close to experiments. By means of parameter variations, stress levels can be reduced and the use of harder coating materials becomes possibl

Flexible Stochastic Volatility Structures for High Frequency Financial Data

Stochastic Volatility (SV) models are widely used in financial applications. To decide whether standard parametric restrictions are justified for a given dataset, a statistical test is required. In this paper, we develop such a test based on the linear state space representation. We provide a simulation study and apply the test to the HFDF96 data set. Our results confirm a linear AR(1) structure for the analyzed stock indices S&P500, Dow Jones Industrial Average and for the exchange rate DEM/USD