Biomedical subjects

Qian Shi

Publications and source records attributed to Qian Shi.

29 records · Page 2Linked to original sources

PubMed2004

Polymeric aqua(nitrato-kappa(2)O,O')(1,10-phenanthroline-kappa(2)N,N')(2,3-pyrazinedicarboxylato-kappa(2)N,O)europium(III) monohydrate.

In polymeric [[Eu(pzdc)(NO(3))(phen)(H(2)O)].H(2)O](n) [pzdc is 2,3-pyrazinedicarboxylate (C(6)H(2)O(4)) and phen is 1,10-phenanthroline (C(12)H(8)N(2))], each europium(III) ion is coordinated by seven O atoms (from three pzdc anions, a nitrate anion and a water molecule) and the two N atoms of the phen ligand, resulting in a nine-coordinated europium(III) center with a distorted monocapped square-antiprismatic coordination polyhedron. Four pzdc anions bridge four europium(III) ions, forming a parallelogram unit, the four vertices of which are occupied by the four pzdc anions. Moreover, each parallelogram unit links six other adjacent parallelogram units, forming a two-dimensional network with disordered lattice water molecules.

Journal Article↗

PubMed2004

Enhanced protein profiling arrays with ELISA-based amplification for high-throughput molecular changes of tumor patients' plasma.

PURPOSE: The purpose of this study is to develop a high-throughput approach to detect protein expression from hundreds and thousands of samples and to apply this technology to profile circulating angiogenic factor protein levels in patients with gynecological tumors. EXPERIMENTAL DESIGN: Analytes containing a mixture of protein are immobilized onto antibody-coated surface of support in array format. The presence of protein in analytes is detected with biotin-labeled antibody coupled with an enhanced chemiluminescence or fluorescence detection system. The exact amount of protein can be quantitatively measured. The expression levels of five angiogenic factors (angiogenin, interleukin 8, vascular endothelial growth factor, platelet-derived growth factor, and epidermal growth factor) from 157 samples were quantitatively measured using this novel protein array technology and were statistically analyzed. The expression patterns of angiogenic factors were analyzed using two-way hierarchical cluster analysis approach. RESULTS: A novel protein array technology, which can simultaneously and quantitatively measure few protein levels from hundreds and thousands of samples was developed. Only minute amounts of sample are required for the assay. This approach also features high sensitivity and specificity. Using this novel protein array approach, we analyzed the plasma expression levels of five angiogenic factors in 137 patients diagnosed with a tumor and 20 controls. Statistical analysis reveals different expression levels of angiogenic factors between patients and controls. Cluster analysis suggests a possible classification of normal subjects from patients. CONCLUSIONS: Enhanced protein profiling arrays provide a high-throughput and sensitive system to detect one or few protein from hundreds and thousands of samples. Such an approach should have broad application in biomedical discovery.

Adolescent↗

PubMed2004

Constitutive and inducible expression and regulation of vascular endothelial growth factor.

Vascular endothelial growth factor (VEGF), which was originally discovered as vascular permeability factor, is critical to human cancer angiogenesis through its potent functions as a stimulator of endothelial cell survival, mitogenesis, migration, differentiation and self-assembly, as well as vascular permeability, immunosuppression and mobilization of endothelial progenitor cells from the bone marrow into the peripheral circulation. Genetic alterations and a chaotic tumor microenvironment, such as hypoxia, acidosis, free radicals, and cytokines, are clearly attributed to numerous abnormalities in the expression and signaling of VEGF and its receptors. These perturbations confer a tremendous survival and growth advantage to vascular endothelial cells as manifested by exuberant tumor angiogenesis and a consequent malignant phenotype. Understanding the regulatory mechanisms of both inducible and constitutive VEGF expression will be crucial in designing effective therapeutic strategies targeting VEGF to control tumor growth and metastasis. In this review, molecular regulation of VEGF expression in tumor cells is discussed.

Endothelial Cells↗

PubMed2003

Catena-poly[bis[aqua(2,2-bipyridine-kappa 2N,N')cobalt(II)]-mu-1,2,4,5-benzenetetracarboxylato-kappa 4O1:O2:O3:O4].

In the title complex, [Co(2)(C(10)H(2)O(8))(C(10)H(8)N(2))(2)(H(2)O)(2)], the four carboxylate groups are fully deprotonated and coordinate to four Co(II) cations in a monodentate fashion, forming a one-dimensional ribbon-like double-chain structure, with centrosymmetric [Co(2)(C(10)H(2)O(8))(C(10)H(8)N(2))(2)(H(2)O)(2)] repeating units and a cavity of approximately 6.8 x 6.6 A. Moreover, a three-dimensional supramolecular structure is formed by face-to-face pi-pi interactions between the aromatic rings of the 2,2'-bipyridine moieties of two adjacent chains, and by hydrogen-bonding interactions between the coordinated aqua O atom and the coordinated carboxyl O atom from different chains.

Journal Article↗

PubMed2003

Novel silver-containing supramolecular frameworks constructed by combination of coordination bonds and supramolecular interactions.

The hydrothermal reactions of AgNO(3), 4,4'-bipy, and carboxylate ligands gave rise to three supramolecular architectures, namely [Ag(bipy)].H(2)SIPA.1/2bipy.H(2)O (1), [Ag(bipy)].1/2H(2)btec.H(2)O (2), and [Ag(bipy)](2).H(2)dpstc.2H(2)O (3) (H(3)SIPA = 5-sulfoisophthalic acid, bipy = 4,4'-bipyridine, H(4)btec = 1,2,4,5-benzenetetracarboxylic acid, H(4)dpstc = 3,3',4,4'-tetracarboxydiphenyl sulfone). All complexes are extended from Ag-bipy linear chains by the combination of coordination bonds and supramolecular interactions in two different approaches. Complexes 1 and 3 comprise two-dimensional frameworks. In the two complexes, a one-dimensional ladderlike structure is first formed by the connection of a Ag-bipy chain through hydrogen bonding between a free carboxylate/bipy ligand and weak coordinative interactions between a free carboxylate ligand and silver ion. The ladderlike structure is then extended to a two-dimensional layer architecture by pi...pi interactions between bipy ligands of the Ag-bipy chains. Complex 2 possesses a three-dimensional framework. The free H(2)btec(2)(-) ligands form a two-dimensional layer network by hydrogen-bonding interactions between protonated and deprotonated carboxylate groups; meanwhile, pi.pi interactions between bipy ligands of Ag-bipy chains also result in a two-dimensional layer. The two layers are further connected by weak Ag-O interactions to generate a three-dimensional supramolecular structure.

Journal Article↗

PubMed2003

Highly efficient rhodium/monodentate phosphoramidite catalyst and its application in the enantioselective hydrogenation of enamides and alpha-dehydroamino acid derivatives.

An easily prepared and highly efficient monodentate phosphoramidite ligand derived from BINOL, (S)-2,2'-O,O-(1,1'-binaphthyl)-dioxo-N,N-diethylphospholidine, was examined in the hydrogenation of both enamides and alpha-dehydroamino acid derivatives. The catalyst provided remarkably high enantioselectivities (up to 99.6% ee for enamides and >99.9% ee for alpha-dehydroamino acid derivatives).

Journal Article↗

PubMed2002

Syntheses and characterizations of copper(II) polymeric complexes constructed from 1,2,4,5-benzenetetracarboxylic acid.

Four polymeric complexes with rectangular grids or channels, [Cu2(btec)(H2O)4*2H2O]n (2), [Cu2(btec)4/4[Cu(Hbtec)2/2(4,4'-Hbpy)(H2O)2]2*4H2O]n (3), [Cu2(btec)(hmt)(H2O)4*8H2O]n (4), and [Cu3(btec)(OH)2]n (5), were designed and constructed from Cu(II) ion and 1,2,4,5-benzenetetracarboxylic acid along with auxiliary ligands (where H4btec = 1,2,4,5-benzenetetracarboxylic acid, 4,4'-Hbpy = monoprotonated 4,4'-bipyridine, and hmt = hexamethylenetetramine). Complexes 2, 3, and 4 have rectangular pores with the size of 6.5 A x 4.5 A, 6 A x 7 A, and 10.1 A x 11.8 A, respectively, while 5 has a channel of 7.4 A x 9.6 A. The complexes show interesting magnetic properties due to the different coordination modes of the carboxylate groups and the presence of auxiliary ligands. On lowering the temperature, the magnetic interactions in 2 are changed from antiferromagnetic to ferromagnetic. For 3, the antiferromagnetic interactions weaken sharply at low temperature. Complex 4 shows ferromagnetic interactions while 5 is antiferromagnetic.

Journal Article↗

PubMed2002

Connexin 43 suppresses human glioblastoma cell growth by down-regulation of monocyte chemotactic protein 1, as discovered using protein array technology.

Previously, we demonstrated that connexin 43 (cx43) suppressed the growth of human glioblastoma cells. To investigate the molecular mechanisms involved in tumor suppression by cx43, we developed a human cytokine array system, which simultaneously detects the expression of 43 cytokines. By using this new technology, we analyzed the cx43-regulated genes in cx43-transfected cells. The cytokine arrays showed that expression of monocyte chemotactic protein-1 (MCP-1) was profoundly reduced in cx43-transfected cells. RT-PCR, immuno-Western blot, and cDNA microarrays further confirmed this observation. Addition of conditioned medium from control-transfected cells and recombinant MCP-1 to cx43-transfected cells significantly enhanced cx43-transfected cell proliferation and colony formation in soft agar. In contrast, addition of neutralization antibody against MCP-1 significantly inhibited cell proliferation in control-transfected cells. Our results suggested that MCP-1 is involved in the suppression of human glioblastoma cell growth by cx43.

Cell Division↗

PubMed2002

Syntheses and characterizations of three-dimensional channel-like polymeric lanthanide complexes constructed by 1,2,4,5-benzenetetracarboxylic acid.

The hydrothermal reaction of YbCl(3) small middle dot6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride resulted in [[Yb((b)btec)(1/4)((d)btec)(3/6)(H(2)O)(2)](4).6H(2)O](n)() (1) (H(4)btec = 1,2,4,5-benzenetetracarboxylic acid), and the solvothermal reaction of Er(NO(3))(3) small middle dot6H(2)O or TbCl(3).6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride in H(2)O/acetic acid gave rise to [[Er(2)((c)btec)(2/4)((e)btec)(2/4)((f)btec)(2/4)(H(2)O)(4)].4H(2)O](n)() (2) and [[Tb(H(2)btec)(2/4)((f)btec)(3/6)(H(2)O)].2H(2)O](n)() (3), respectively. Complex 1 crystallizes in monoclinic space group C2/m with a = 20.8119(5) A, b = 17.6174(1) A, c = 5.7252(2) A, beta = 92.324(1) degrees, and Z = 1. 1 possesses a three-dimensional framework consisting of eight-coordinate ytterbium centers and two kinds of channels along the c axis. Complex 2 crystallizes in triclinic space group P with a = 9.6739(5) A, b = 11.0039(5) A, c = 11.5523 A, alpha = 104.8330(10) degrees, beta = 91.0000(10) degrees, gamma = 114.2570(10) degrees, and Z = 2. 2 has a three-dimensional framework comprising both eight- and nine-coordinate erbium centers and channels along the a axis. Complex 3 crystallizes in monoclinic space group P2(1)/n with a = 10.7246(12) A, b = 7.1693(9) A, c = 17.158(2) A, beta = 97.109(2) degrees, and Z = 4. 3 shows a three-dimensional framework containing nine-coordinate terbium centers and channels along the b axis. Uncoordinated water molecules occupy the channels in the three complexes. TGA and XRPD were determined for the three complexes, and the results illustrate that the framework of 1 is retained upon removal of uncoordinated and coordinated water molecules.

Journal Article↗

PubMed2001

Mouse Models of Metastatic Pancreatic Adenocarcinoma.

Pancreatic adenocarcinoma is a deadly disease. Its etiology is unknown, and metastatic disease kills themajority of patients who have it. Effective prevention is clearly the ultimate goal for eradicating this diseaseprovided that the effects of environmental and genetic elements on pancreatic cancer development arefully understood. Currently, it appears that the control of pancreatic cancer metastasis is of immediateurgency. Fulfillment of this difficult task relies on knowledge of the cellular and molecular biology of metastasis.The use of relevant animal models will help define each aspect of this complicated process.

Journal Article↗

PubMed2001

A Novel, Clinically Relevant Animal Model of Metastatic Pancreatic Adenocarcinoma Biology and Therapy.

In this study, we report a metastatic model of Panc02 murine pancreatic adenocarcinoma. Parental Panc02cells were orthotopically implanted into the pancreas of syngeneic C57BL/6 mice. Tumor cells were isolatedfrom liver micrometastases 90 d after tumor implantation and established as a culture (Panc02-H1).The Panc02-H1 cells were then implanted into the pancreas of mice. Liver metastases were then collectedand established as Panc02-H2 cells. This process was repeated until the Panc02-H7 cell line was established.These cells were extremely aggressive after implantation as manifested by progressive growth in the pancreas,peritoneal dissemination, and distant metastasis to multiple organs, including the liver and lungs.Moreover, Panc02-H7 cells expressed the inducible nitric oxide synthase gene at a very low level in cultureand produced highly vascularized tumors having a large number of infiltrating macrophages. Collectively,this model system should be a valuable tool for investigating the molecular mechanisms governing pancreaticcancer growth and metastasis and exploring potential treatment modalities for this disease.

Journal Article↗