Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiopoietins(ANGPT) and their endothelial cell-specific tyrosine kinase receptors TEK are the major regulators of blood vessels angiogenesis under physiological and pathologic conditions. ANGPT1 is essentially involved in maturation, stabilization, and remodeling of blood vessels through inducing TEK autophosphorylation, promoting endothelial cell migration and survival. Instead, ANGPT2 appears to act as a natural antagonist of ANGPT1, it can activate vascular remodeling with the presence of vascular endothelial growth factor(VEGF) or regress frank blood vessels under the absence of VEGF. High expression of angiopoietins and TEK is often detected in tumor tissues. Many studies showed that disrupting the ANGPT/TEK receptor pathway could inhibit the growth of a number of murine tumors and human tumors. Thus, it is possible that inhibitors targeting the ANGPT/TEK pathway will have broad clinical utility to treatment of cancer.
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PMID:[The regulating roles of angiopoietins/TEK-2 in angiogenesis]. 1645 89

A new type of surfactant with a hydrophile of dendritic polyethylenimine (C(12)(EI)(7)) was synthesized by a cationic polymerization of dodecylamine with aziridine and was used as a stabilizer to prepare Pt colloid, which is then used in situ to prepare carbon-supported Pt nanoparticles. The effects of supporting carbon, surfactant concentration, and calcination time on the nanoparticle size and catalytic performance were determined from the transmission electron microscopic analyses and cyclic voltammograms. In the presence of carbon, the Pt particle size increased slightly with lower C(12)(EI)(7) content, while those with higher C(12)(EI)(7) concentrations remained unchanged. For the heat-treated Pt/C catalyst, the molar ratio of C(12)(EI)(7) to H(2)PtCl(6) ([N]/[Pt] ratio) dominated the growth of Pt nanoparticles. The size decreased from 7.6 nm for a [N]/[Pt] ratio of 5 to 3.8 nm for a [N]/[Pt] ratio of 40. X-ray photoelectron spectroscopy revealed that metallic Pt(0) (81.6%) predominated the Pt species in the heat-treated catalyst, which is more than the commercial E-TEK catalyst. The data show clearly that thermal treatment had successively removed the stabilizing shells; moreover, it did not cause serious aggregation of particles in the presence of C(12)(EI)(7) and thus enhanced the catalytic activity. The interaction between Pt and C(12)(EI)(7) were studied and were explained in terms of a mechanism of dual-functional stabilization both on carbon and in the thermal treatment.
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PMID:Stabilizing effect of pseudo-dendritic polyethylenimine on platinum nanoparticles supported on carbon. 1649 11

Cutaneous leg ulcers are common in sickle cell anaemia and their risk might be genetically determined. Sickle cell anaemia patients were studied to examine the relationship of leg ulcers with haemolysis and with single nucleotide polymorphisms (SNPs) in candidate genes that could affect sickle vasoocclusion. Leg ulcer patients had lower haemoglobin levels and higher levels of lactate dehydrogenase, bilirubin, aspartate transaminase and reticulocytes than did control patients with sickle cell anaemia but without leg ulcers. Age-adjusted comparisons showed that sickle cell anaemia-alpha thalassaemia was more frequent among controls than cases. These results strongly suggested that the likelihood of having leg ulcers was related to the intensity of haemolysis. 215 SNPs in more than 100 candidate genes were studied. Associations were found with SNPs in Klotho, TEK and several genes in the TGF-beta/BMP signalling pathway by genotypic association analyses. KL directly or indirectly promotes endothelial nitric oxide (NO) production and the TEK receptor tyrosine kinase is involved in angiogenesis. The TGF-beta/BMP signalling pathway modulates wound healing and angiogenesis, among its other functions. Haemolysis-driven phenotypes, such as leg ulcers, could be improved by agents that reduce sickle erythrocyte density or increase NO bioavailability.
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PMID:Sickle cell leg ulcers: associations with haemolysis and SNPs in Klotho, TEK and genes of the TGF-beta/BMP pathway. 1668 47

Pseudo-dendritic polyethyleniminated poly(oxypropylene)diamine (D400(EI)(20)) was used as a stabilizer and promoter to prepare Pt nanoparticles in aqueous solution, which was then deposited on carbon surface followed by calcination. After being deposited on carbon surface, no Pt(0) could be detected in the solution phase. In all steps, the increasing molar ratio of the amino groups of D400(EI)(20) to H(2)PtCl(6) ([N]/[Pt]) drastically reduced the size and the polydispersity and kept a constant low value after [N]/[Pt] = 20. Under a [N]/[Pt] ratio of 20, the particle sizes obtained from transmission electron microscopy (TEM) were very small in solution (2.7-2.4 nm) and remained the same after being deposited on carbon surface (2.7-2.4 nm), and were only slightly increased to 3.6-3.0 nm after calcination. The stabilizing ability of D400(EI)(20) to Pt on carbon surface before and after calcination can be interpreted by the existence of binding energy between Pt and amine nitrogen. The X-ray diffraction (XRD) pattern together with the TEM image reveals that the obtained Pt nanoparticles exist in single-crystal form. The results of photoelectron spectroscopy (XPS) evidence that the metallic Pt(0) rather than the oxidized Pt is the predominant species in the Pt/C catalysts. The electrochemical active surface (EAS) area of the Pt/C catalyst is only slightly higher than that of the E-TEK Pt/C catalyst, but the utilization factor (93.4%) is remarkably higher than the latter (62.8%). The increasing time of thermal treatment increases the crystallinity of Pt(0) on carbon, accompanied by the increasing EAS areas, which corresponds to its enhanced electrocatalytic performance to methanol oxidation.
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PMID:Enhanced stabilization and deposition of Pt nanocrystals on carbon by dumbbell-like polyethyleniminated poly(oxypropylene)diamine. 1670 34

Platinum Hollow Spheres (PHSs) with diameters less than 10 nm were successfully synthesized by using Co as a sacrificial template and H2PtCl6 as an oxidizing agent at 95 degrees C. The formation of PHSs at this temperature was not affected by citrate reduction and mainly depended on the pH. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the platinum hollow sphere was mainly constructed by fcc (face cubic center) platinum with tiny crystallites on the shell. The performance of PHSs for methanol electro-oxidation was evaluated and compared with commercial E-TEK platinum black. Electrochemical measurement by cyclic voltammetry (CV) demonstrated that the electrochemical surface area of PHSs was about twice higher than E-TEK platinum black. Therefore, the synthesized PHSs had higher electrocatalytic activity for methanol electro-oxidation.
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PMID:Synthesis and characterization of sub-10 nm Platinum Hollow Spheres as electrocatalyst of direct methanol fuel cell. 1673 73

In this study, ordered macroporous carbon with a three-dimensional (3D) interconnected pore structure and a graphitic pore wall was prepared by chemical vapor deposition (CVD) of benzene using inverse silica opal as the template. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectrometry, nitrogen adsorption, and thermogravimetric analysis techniques were used to characterize the carbon samples. The electrochemical properties of the carbon materials as a carbon-based anode for lithium-ion batteries and as a Pt catalyst support for room-temperature methanol electrochemical oxidation were examined. It was observed that the CVD method is a simple route to fabrication of desired carbon nanostructures, affording a carbon with graphitic pore walls and uniform pores. The graphitic nature of the carbon enhances the rate performance and cyclability in lithium-ion batteries. The specific capacity was found to be further improved when SnO(2) nanoparticles were supported on the carbon. The specific activity of Pt catalyst supported on the carbon materials for room-temperature methanol electrochemical oxidation was observed to be higher than that of a commercial Pt catalyst (E-TEK).
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PMID:Synthesis of graphitic ordered macroporous carbon with a three-dimensional interconnected pore structure for electrochemical applications. 1685 11

We study the isothermal hydrogen adsorption and reaction at the E-TEK electrode of a polymer electrolyte fuel cell with a Nafion 117 membrane by impedance spectroscopy at 30 degrees C. We find that the impedance diagram must include a Gerischer phase element. Constant phase elements are not sufficient to describe the experimental data. This means that an adsorption reaction takes place in combination with surface diffusion of hydrogen in the carbon layer located before the platinum surface, separate from the charge transfer step at the platinum particle surface. We are not able to distinguish between molecular or atomic hydrogen diffusion on carbon. We predict and find that the relaxation time of the adsorption step is independent of the applied potential. Water may also enter rate-limiting steps in the electrode reaction, but its role needs further clarification.
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PMID:A Gerischer phase element in the impedance diagram of the polymer electrolyte membrane fuel cell anode. 1685 74

We report a novel process to prepare well-dispersed Pt nanoparticles on CNTs. Pt nanoparticles, which were modified by the organic molecule triphenylphosphine, were deposited on multiwalled carbon nanotubes by the organic molecule, which acts as a cross linker. By manipulating the relative ratio of Pt nanoparticles and multiwalled carbon nanotubes in solution, Pt/CNT composites with different Pt content were achieved. The so-prepared Pt/CNT composite materials show higher electrocatalytic activity and better tolerance to poisoning species in methanol oxidation than the commercial E-TEK catalyst, which can be ascribed to the high dispersion of Pt nanoparticles on the multiwalled carbon nanotube surface.
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PMID:Controllable pt nanoparticle deposition on carbon nanotubes as an anode catalyst for direct methanol fuel cells. 1685 91

TiO2 nanotubes have been synthesized using anodic alumina membrane as template. Highly dispersed platinum nanoparticles have been supported on the TiO2 nanotube. The supported system has been characterized by electron microscopy and electrochemical analysis. SEM image shows that the nanotubes are well aligned and the TEM image shows that the Pt particles are uniformly distributed over the TiO2 nanotube support. A homogeneous structure in the composite nanomaterials is indicated by XRD analysis. The electrocatalytic activity of the platinum catalyst supported on TiO2 nanotubes for methanol oxidation is found to be better than that of the standard commercial E-TEK catalyst.
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PMID:Electro-oxidation of methanol on TiO2 nanotube supported platinum electrodes. 1702 26

Dicer is a key enzyme involved in the maturation of microRNAS (miRNAs). miRNAs have been shown to be regulators of gene expression participating in the control of a wide range of physiological pathways. To assess the role of Dicer and consequently the importance of miRNAs in the biology and functions of human endothelial cells (EC) during angiogenesis, we globally reduced miRNAs in ECs by specific silencing Dicer using siRNA and examined the effects on EC phenotypes in vitro. The knockdown of Dicer in ECs altered the expression (mRNA and/or protein) of several key regulators of endothelial biology and angiogenesis, such as TEK/Tie-2, KDR/VEGFR2, Tie-1, endothelial nitric oxide synthase and IL-8. Although, Dicer knockdown increased activation of the endothelial nitric oxide synthase pathway it reduced proliferation and cord formation of EC in vitro. The miRNA expression profile of EC revealed 25 highly expressed miRNAs in human EC and using miRNA mimicry, miR-222/221 regulates endothelial nitric oxide synthase protein levels after Dicer silencing. Collectively, these results indicate that maintenance and regulation of endogenous miRNA levels via Dicer mediated processing is critical for EC gene expression and functions in vitro.
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PMID:Dicer dependent microRNAs regulate gene expression and functions in human endothelial cells. 1737 31


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