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981.
The goal of the present study is to test the hypothesis that LPA induces proliferation of astrocytes in hippocampus in vivo via phosphorylation of ERK 1/2. We first characterized the expression of GFAP, a special marker fiber protein of astrocytes,
in brain slices after direct injection of LPA into hippocampus by immunohistochemistry, and found that LPA induced a remarkable
proliferation of astrocytes. Then double-lablled immunofluorescence was used to detect GFAP and phosphorylation ERK 1/2 (p-ERK
1/2), LPA induced an immediate (10 min) and transient (<30 min) phosphorylation of ERK 1/2, and sequence sustained activation
of ERK 1/2 was observed, which last for at least 3 weeks after injection of LPA. Reactions are inhibited by U0126, a specific
pharmacological mitogen-activated protein kinase (MEK) inhibitor. Laser confocal scanning was used to study spatial relationship
of p-ERK and astrocytes. Amazingly, the early (<7 days) phosphorylation of ERK 1/2 is not expressed in astrocytes but in area
where neurons and/or in other cell type(s) occupied, expression of p-ERK 1/2 in astrocytes is not detected until 14 days after
LPA injection and lasts for at least 3 weeks. Taken together, these data suggest that LPA play an important role in proliferation
of astrocytes through phosphorylation of ERK 1/2 in hippocampus. It provides further proof for the functions of LPA in CNS
injury, and may contribute to clinical therapy for relative diseases. 相似文献
982.
XinZHANG DeHuaHE QiJiangZHANG BoQingXU QiMingZHU 《中国化学快报》2003,14(10):1066-1069
Comparatively high CH3OH selectivity (60.0%) and yield (6.7%) were obtained on MoOx/(LaCoO3 Co3O4) catalysts in selective oxidation of methane to methanol using molecular oxygen as oxidant. The interaction between MoOx and La-Co-oxide modified the molecular structure of molybdenum oxide and the ratio of O^-/O^2- on the catalyst surface, which controlled the catalytic performance of MoOx/(LaCoO3 Co3O4) catalysts. 相似文献
983.
José M. Bartoloméa Jesús AlcázarJ.Ignacio Andrés Marcel De BruynJavier Fernández Encarna MatesanzKristof Van Emelen 《Tetrahedron letters》2003,44(47):8545-8548
The synthesis of a series of novel analogues of the 3-substituted-2,3-dihydro-1,4-dioxino[2,3-b]pyridine core, modified in the non-aromatic ring, is described. Due to the presence of a versatile hydroxymethyl group in their structure, these novel scaffolds are attractive intermediates for the preparation of potential new therapeutic agents. 相似文献
984.
P. R. N. De Souza D. A. G. Aranda J. W. De M. Carneiro C. Da S. B. De Oliveira O. A. C. Antunes F. B. Passos 《International journal of quantum chemistry》2003,92(4):400-411
B3 LYP hybrid functional with LACVP* pseudopotential was applied for the optimization of geometries of complexes resulting from interaction of benzene, pyridine, naphthalene, and quinoline with Ptn (n = 4, 7) clusters. For benzene‐containing complexes, the most stable form corresponds to a bridge adsorption, with benzene undergoing considerable geometric distortions, assuming a boat‐like conformation. C? H bonds are bended upward from the plane of the cluster. C? C bonds stretch, especially when they form π‐complexes with low coordinated Pt atoms. Some arrangements for pyridine complexes involving the N atom of the organic moiety undergo further distortions, apparently preserving a formal C? N π bond. Except for that distortion, the behavior of any heteroaromatic complex is similar to that of benzene in the same arrangement. The quinoline–Pt7 complex can suitably be used for simulation of the cinchonidine (CD) anchorage over Pt. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 相似文献
985.
A high-performance capillary electrophoretic (CE) method with electrochemical detection (ED) has been developed for determination of the pharmacologically active flavonoids in Ginkgo biloba L. and phytopharmaceuticals containing its extract. Epicatechin, catechin, rutin, apigenin, luteolin, and quercetin are important flavonoids in this plant. Operated in a wall-jet configuration, a 300 micro m diameter carbon-disk electrode was used as working electrode with good response to the six analytes at +1000 mV (relative to the SCE). Under the optimum conditions, the analytes were separated within 22 min in a borax buffer (pH 9.0). Excellent linearity was obtained over two orders of magnitude and detection limits (S/N=3) ranged from 1.4 x 10(-7) to 5.0 x 10(-7) g mL(-1) for all six analytes. The method was successfully used for assay of Ginkgo biloba L. and its phytopharmaceuticals after a relatively simple extraction procedure; the results obtained were satisfactory. 相似文献
986.
Arie van Der Kaaden Johan Haverkamp Jaap J. Boon Jan W. De Leeuw 《Journal of Analytical and Applied Pyrolysis》1983,5(3):199-220
Inorganic additives, viz. Na2CO3, NaOH, HCl, ZnC2, NaH2PO4, Na2HPO4, NaCl. MgSO4 and sea salt, to the pyrolysis matrix change the pyrolysis-mass spectrum of amylose significantly. Carbonyl compounds, acids and their lactones, furans, pyranones anhydrosugars and aromatic substances are found in different ratios under the various conditions, as determined by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).Carbonyl compounds, acids and lactones are released from alkaline and neutral matrices. Furans and anhydrohexoses are particularly formed under neutral and acidic conditions. Pyranones are specific for phosphate matrices. Unsaturated hydrocarbons and aromatic substances arise from strongly alkaline or dehydrating matrices. Degradation pathways are proposed for various compound categories.The results of pyrolysis-mass spectrometry and Py-GC-MS are highly compatible. 相似文献
987.
The uncatalyzed 1,4-addition of phenylmagnesium bromide and furylmagnesium iodide to methyl 5-methoxy-1,5-cyclohexadienylcarboxylate (), directly followed by alkylation and hydrolysis leads to the corresponding cyclohexanones of type (R1 and R2 trans) in moderate to high yield. 相似文献
988.
The systematic preparation of partially fluorinated pentafluorosulfur alkanes containing no additional halogens is reported. Thus, the indirect addition of “HF” (via KF/formamide) to SF5CH=CF2, SF5CFCF2, and SF5C(CF3)CF2 produces SF5CH(in2)CF3, SF5CHFCF3, and SF5C(CF3)2H respectively. The monohydryl-pentafluorosulfur-F- alkanes react readily with S2O6F2 to form the corresponding fluorosulfates by oxidative displacement of hydrogen, while the dihydryl derivative undergoes cleavage to produce F-acetyl fluoride. Efforts to convert some of the new materials to the important but unknown pentafluorosulfur “ketone,” SF5C(O)CF3, were unsuccessful. 相似文献
989.
A novel generally applicable synthesis of coumarins from phenolic substrates utilizing ring-closing metathesis is described. This sequence involves O-allylation of phenols followed by ortho-Claisen rearrangement, subsequent based-induced isomerization affording 2-(1-propenyl)phenols, acylation with acryloyl chloride, and finally ring-closing metathesis (RCM) with Grubbs’ second generation catalyst. 相似文献
990.