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In JoVE (1)
Other Publications (10)
- Physical Review Letters
- Journal of the American Chemical Society
- American Heart Journal
- Neuropharmacology
- European Journal of Radiology
- PloS One
- The Review of Diabetic Studies : RDS
- Physical Chemistry Chemical Physics : PCCP
- Journal of Ophthalmology
- Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
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Articles by Chee Liew in JoVE
JoVE General
Transfectando e Nucleofecting células-tronco pluripotentes induzidas
Apesar dos avanços recentes na modificação genética, transfecção de células estaminais embrionárias humanas (hESCs) continua a ser um processo caprichoso. Para nosso conhecimento, métodos sistemáticos e eficiente para transfectar células-tronco pluripotentes induzidas (iPSCs) não foram relatados. Aqui, descrevemos protocolos robustos de forma eficiente e transfectar nucleofect iPSCs humanos.
Other articles by Chee Liew on PubMed
First-principles Molecular-dynamics Simulations of a Hydrated Electron in Normal and Supercritical Water
A first principles study of a hydrated electron in water at ordinary and supercritical conditions is presented. In the first case, the electron cleaves a cavity in the hydrogen bond network in which six H2O molecules form the solvation shell. The electron distribution assumes an ellipsoidal shape, and the agreement of the computed and the experimental optical absorption seems to support this picture. At supercritical conditions, instead, the H-bond network is not continuous and allows us to predict that the electron localizes in preexisting cavities in a more isotropic way. Four water molecules form the solvation shell but the localization time shortens significantly.
Hydrogen Bond Driven Chemical Reactions: Beckmann Rearrangement of Cyclohexanone Oxime into Epsilon-caprolactam in Supercritical Water
Recent experiments have shown that supercritical water (SCW) has the ability to accelerate and make selective synthetic organic reactions, thus replacing the common but environmentally harmful acid and basic catalysts. In an attempt to understand the intimate mechanism behind this observation, we analyze, via first-principles molecular dynamics, the Beckmann rearrangement of cyclohexanone oxime into epsilon-caprolactam in supercritical water, for which accurate experimental evidence has been reported. Differences in the wetting of the hydrophilic parts of the solute, enhanced by SCW, and the disrupted hydrogen bond network are shown to be crucial in triggering the reaction and in making it selective. Furthermore, the enhanced concentrations of H(+) in SCW play an important role in starting the reaction.
Accuracy of 64-row Multidetector Computed Tomography in Detecting Coronary Artery Disease in 134 Symptomatic Patients: Influence of Calcification
The new 64-row multidetector computed tomography (CT)-assisted angiography can now detect coronary artery disease with shorter breath-hold time and at faster heart rates for symptomatic patients. We aim to determine if the 64-row scanner can also overcome limitations due to mild to moderate calcification.
MGluR5 is Involved in Dendrite Differentiation and Excitatory Synaptic Transmission in NTERA2 Human Embryonic Carcinoma Cell-derived Neurons
The pluripotent human embryonic carcinoma cell line NTERA2 readily differentiates into neurons when exposed to retinoic acid in vitro. These neurons show characteristic morphology with long processes and they express neuronal markers TUJ-1 and NeuN. NTERA2-derived neurons can regulate Ca2+ signalling through ionotropic glutamate (iGluR) and muscarinic receptors (mAChRs). Little is known, however, about the role of metabotropic glutamate receptors (mGluRs) in these neurons. Here we show that NTERA2-derived neurons express functional mGluR5, which is involved in Ca2+ signalling. Blocking mGluR5 activity at early stages of differentiation leads to fewer dendrites and a reduction in miniature excitatory postsynaptic currents (mEPSCs). Furthermore, cells cultured in the presence of the mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) show reduced N-methyl-D-aspartate (NMDA) receptor-mediated Ca2+ mobilisation but increased alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor Ca2+ permeability. During normal neuronal development, the edited GluR2 renders AMPARs Ca2+ impermeable. The increased Ca2+ permeability of AMPARs in MPEP-treated neurons is due to the reduced expression of GluR2 subunit protein. Thus, mGluR5 activity at early stages of differentiation is likely to play a role in the development of multipotent cell-derived neurons.
Assessment of Global and Regional Left Ventricular Function Using 64-slice Multislice Computed Tomography and 2D Echocardiography: a Comparison with Cardiac Magnetic Resonance
To compare the assessment of global and regional left ventricular (LV) function using 64-slice multislice computed tomography (MSCT), 2D echocardiography (2DE) and cardiac magnetic resonance (CMR).
PAX4 Enhances Beta-cell Differentiation of Human Embryonic Stem Cells
Human embryonic stem cells (HESC) readily differentiate into an apparently haphazard array of cell types, corresponding to all three germ layers, when their culture conditions are altered, for example by growth in suspension as aggregates known as embryoid bodies (EBs). However, this diversity of differentiation means that the efficiency of producing any one particular cell type is inevitably low. Although pancreatic differentiation has been reported from HESC, practicable applications for the use of beta-cells derived from HESC to treat diabetes will only be possible once techniques are developed to promote efficient differentiation along the pancreatic lineages.
Stem Cell Therapy to Treat Diabetes Mellitus
Transplantation of pancreatic islets offers a direct treatment for type 1 diabetes and in some cases, insulin-dependent type 2 diabetes. However, its widespread use is hampered by a shortage of donor organs. Many extant studies have focused on deriving beta-cell progenitors from pancreas and pluripotent stem cells. Efforts to generate beta-cells in vitro will help elucidate the mechanisms of beta-cell formation and thus provide a versatile in vivo system to evaluate the therapeutic potential of these cells to treat diabetes. Various successful experiments using beta-cells in animal models have generated extensive interest in using human embryonic stem cells to restore normoglycemia in diabetic patients. While new techniques are continually unveiled, the success of beta-cell generation rests upon successful manipulation of culture conditions and the induction of key regulatory genes implicated in pancreas development. In this review, we compare successfully conducted protocols, highlight essential steps and identify some of the remarkable shortfalls common to these methods. In addition, we discuss recent advancements in the derivation of patient-specific pluripotent stem cells that may facilitate the use of autologous beta-cells in stem cell therapy.
Effective Control of the Transport Coefficients of a Coarse-grained Liquid and Polymer Models Using the Dissipative Particle Dynamics and Lowe-Andersen Equations of Motion
The dynamics of coarse-grained models obtained through iterative Boltzmann inversion [J. Comput. Chem., 2003, 24, 1624] is always faster than that of the parent atomistic models. In this work, the dissipative particle dynamics (DPD) and Lowe-Andersen (LA) equations of motion are applied in coarse-grained simulations to slow down the coarse-grained dynamics. Both methods provide effective friction and both conserve the linear momentum locally, so that they can be used for the calculation of viscosities. Coarse-grained models of liquid ethylbenzene and of short-chain polystyrene melts are studied. Based on the simulation of ethylbenzene at four different temperatures, empirical rules are proposed for choosing the noise strength in DPD or the bath collision frequency in LA dynamics to reproduce the diffusion coefficients of the fully atomistic simulation. The rules developed using the ethylbenzene system are finally tested on the polystyrene melt where they lead to a close reproduction of the experimental diffusion coefficient.
Efficient Transduction of Feline Neural Progenitor Cells for Delivery of Glial Cell Line-derived Neurotrophic Factor Using a Feline Immunodeficiency Virus-based Lentiviral Construct
Work has shown that stem cell transplantation can rescue or replace neurons in models of retinal degenerative disease. Neural progenitor cells (NPCs) modified to overexpress neurotrophic factors are one means of providing sustained delivery of therapeutic gene products in vivo. To develop a nonrodent animal model of this therapeutic strategy, we previously derived NPCs from the fetal cat brain (cNPCs). Here we use bicistronic feline lentiviral vectors to transduce cNPCs with glial cell-derived neurotrophic factor (GDNF) together with a GFP reporter gene. Transduction efficacy is assessed, together with transgene expression level and stability during induction of cellular differentiation, together with the influence of GDNF transduction on growth and gene expression profile. We show that GDNF overexpressing cNPCs expand in vitro, coexpress GFP, and secrete high levels of GDNF protein-before and after differentiation-all qualities advantageous for use as a cell-based approach in feline models of neural degenerative disease.
Performance Database: Capturing Data for Optimizing Distributed Streaming Workflows
The performance database (PDB) stores performance-related data gathered during workflow enactment. We argue that, by carefully understanding and manipulating these data, we can improve efficiency when enacting workflows. This paper describes the rationale behind the PDB, and proposes a systematic way to implement it. The prototype is built as part of the Advanced Data Mining and Integration Research for Europe project. We use workflows from real-world experiments to demonstrate the usage of PDB.
