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41.
42.
Ellmark P Belov L Huang P Lee CS Solomon MJ Morgan DK Christopherson RI 《Proteomics》2006,6(6):1791-1802
A technique of fluorescence multiplexing is described for analysis of the plasma membrane proteome of colorectal cancer cells from surgically resected specimens, enabling detection and immunophenotyping when the cancer cells are in the minority. A single-cell suspension was prepared from a colorectal tumour, and the mixed population of cells was captured on a CD antibody microarray. The cancer cells were detected using a fluorescently tagged antibody for carcinoembryonic antigen (CEA-Alexa647) or epithelial cell adhesion marker (EpCAM-Alexa488). Using this multiplexing procedure, dot patterns from colorectal cancers were distinct from those of adjacent normal tissue. Subtraction of the expression levels for each antigen from normal tissue from those for the cancer shows differential expression in the cancer of CD66c, CD15s, CD55, CD45, CD71, CD45RO, CD11b and CEA, in descending order. Cells captured on the same microarray were also labelled with fluorescent CD3-phycoerythrin antibody revealing the presence of tumour-infiltrating lymphocytes. The immunophenotypes of T lymphocytes from the tumour samples showed differential expression of HLA-DR, TCR alpha/beta, CD49d, CD52, CD49e, CD5, CD95, CD28, CD38 and CD71, in descending order. Fluorescence multiplexing of mixed cell populations captured on a single antibody microarray enables expression profiling of multiple sub-populations of cells within a tumour sample. 相似文献
43.
44.
Acceptor specificity of the human leukocyte alpha3 fucosyltransferase: role of FucT-VII in the generation of selectin ligands 总被引:2,自引:2,他引:0
Britten CJ; van den Eijnden DH; McDowell W; Kelly VA; Witham SJ; Edbrooke MR; Bird MI; de Vries T; Smithers N 《Glycobiology》1998,8(4):321-327
The alpha3 fucosyltransferase, FucT-VII, is one of the key
glycosyltransferases involved in the biosynthesis of the sialyl Lewis X
(sLex) antigen on human leukocytes. The sialyl Lewis X antigen
(NeuAcalpha(2-3)Galbeta(1-4)[Fucalpha(1-3)]GlcNAc-R) is an essential
component of the recruitment of leukocytes to sites of inflammation,
mediating the primary interaction between circulating leukocytes and
activated endothelium. In order to characterize the enzymatic properties of
the leukocyte alpha3 fucosyltransferase FucT-VII, the enzyme has been
expressed in Trichoplusia ni insect cells. The enzyme is capable of
synthesizing both sLexand sialyl-dimeric-Lexstructures in vitro , from
3'-sialyl-lacNAc and VIM-2 structures, respectively, with only low levels
of fucose transfer observed to neutral or 3'-sulfated acceptors. Studies
using fucosylated NeuAcalpha(2-3)-(Galbeta(1- 4)GlcNAc)3-Me acceptors
demonstrate that FucT-VII is able to synthesize both di-fucosylated and
tri-fucosylated structures from mono- fucosylated precursors, but
preferentially fucosylates the distal GlcNAc within a polylactosamine
chain. Furthermore, the rate of fucosylation of the internal GlcNAc
residues is reduced once fucose has been added to the distal GlcNAc. These
results indicate that FucT-VII is capable of generating complex selectin
ligands, in vitro , however the order of fucose addition to the lactosamine
chain affects the rate of selectin ligand synthesis.
相似文献
45.
Purified aspartate carbamoyltransferase from Escherichia coli K12 (carbamoylphosphate: L-aspartate carbamyltransferase, EC 2.1.3.2) shows greater activity with nucleotide effectors as the magnesium nucleotide complex than with similar amounts of the sodium nucleotide. Regulation of aspartate carbamoyltransferase activity in vivo may occur by changes in the total concentration of regulatory nucleotides or, under conditions of magnesium-limited growth, by variation of the saturation of the nucleotides with magnesium. 相似文献
46.
David A Baldwin Deolinda MR de Sousa 《Biochemical and biophysical research communications》1981,99(4):1101-1107
The kinetics of iron release from N-terminal and C-terminal monoferric human transferrins has been studied using EDTA as the accepting chelate. In the absence of added salts iron release from the N-terminal site is more facile but the relative lability can be reversed by the addition of NaClO4, NaCl and LiCl. The results indicate that both anions and cations can affect the lability of the two sites. Since the relative lability of the two monoferrictransferrins is affected by fairly moderate concentrations of NaCl and NaClO4 we suggest that the ionic composition serum may play an important role in determining the observed distribution of iron among the sites. A new method for the preparation of N-terminal monoferrictransferrin is described. 相似文献
47.
Pulmonary gas exchange during altered density gas breathing 总被引:1,自引:0,他引:1
48.
Natural killer (NK) cells play an important role in innate and adaptive immune responses to obligate intracellular pathogens. Nevertheless, the regulation of NK cell trafficking and migration to inflammatory sites is poorly understood. Exodus-1/MIP-3alpha/LARC, Exodus-2/6Ckine/SLC, and Exodus-3/MIP-3beta/ELC/CKbeta-11 are CC chemokines that share a unique aspartate-cysteine-cysteine-leucine motif near their amino terminus and preferentially stimulate the migration of T lymphocytes. The effects of Exodus chemokines on human NK cells were examined. Exodus-1, -2, and -3 did not induce detectable chemotaxis of resting peripheral blood NK cells. In contrast, Exodus-2 and -3 stimulated migration of polyclonal activated peripheral blood NK cells in a dose-dependent fashion. Exodus-2 and -3 also induced dose-dependent chemotaxis of NKL, an IL-2-dependent human NK cell line. Results of modified checkerboard assays indicate that migration of NKL cells in response to Exodus-2 and -3 represents true chemotaxis and not simply chemokinesis. Exodus-1, -2, and -3 did not induce NK cell proliferation in the absence of other stimuli. Nevertheless, Exodus-2 and -3 significantly augmented IL-2-induced proliferation of normal human CD56(dim) NK cells. In contrast, Exodus-1, -2, and -3 did not affect the cytolytic activity of resting or activated peripheral blood NK cells. Expression of message for CCR7, a shared receptor for Exodus-2 and -3, was detected in activated polyclonal NK cells and NKL cells but not resting NK cells. Taken together, these results indicate that Exodus-2 and -3 can participate in the recruitment and proliferation of activated NK cells. Exodus-2 and -3 may regulate interactions between T cells and NK cells that are crucial for the generation of optimal immune responses. 相似文献
49.
Sianos G Kay IP Carlier SG Lighart JM Wardeh AJ Coen VL Levendag PC Serruys PW 《International journal of cardiovascular interventions》2000,3(2):121-125
The application of beta-radiation in coronary arteries is a promising new technique for the treatment of in-stent restenosis. This is the first case in which the 5 F. delivery catheter of the Beta-Cath trade mark system was advanced through the struts of a stent, previously deployed in an adjacent branch, so as to deliver radiation to the target vessel. 相似文献
50.
Lee M Chan CW Mitchell Guss J Christopherson RI Maher MJ 《Journal of molecular biology》2005,348(3):523-533
Escherichia coli dihydroorotase has been crystallized in the presence of the product, L-dihydroorotate (L-DHO), and the structure refined at 1.9A resolution. The structure confirms that previously reported (PDB entry 1J79), crystallized in the presence of the substrate N-carbamyl-D,L-aspartate (D, L-CA-asp), which had a dimer in the asymmetric unit, with one subunit having the substrate, L-CA-asp bound at the active site and the other having L-DHO. Importantly, no explanation for the unusual structure was given. Our results now show that a loop comprised of residues 105-115 has different conformations in the two subunits. In the case of the L-CA-asp-bound subunit, this loop reaches in toward the active site and makes hydrogen-bonding contact with the bound substrate molecule. For the L-DHO-bound subunit, the loop faces in the opposite direction and forms part of the surface of the protein. Analysis of the kinetics for conversion of L-DHO to L-CA-asp at low concentrations of L-DHO shows positive cooperativity with a Hill coefficient n=1.57(+/-0.13). Communication between subunits in the dimer may occur via cooperative conformational changes of the side-chains of a tripeptide from each subunit: Arg256-His257-Arg258, near the subunit interface. 相似文献