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71.
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Interleukin-3, GM-CSF, and TPA induce distinct phosphorylation events in an interleukin 3-dependent multipotential cell line 总被引:9,自引:0,他引:9
The mechanism of action of the hemopoietic growth factor, murine interleukin-3 (mIL-3), was investigated using an mIL-3-dependent multipotential hematopoietic cell line, B6SUtA1. Murine granulocyte- macrophage colony-stimulating factor (mGM-CSF) was as potent as mIL-3 in stimulating these cells. In addition, sodium orthovanadate, an inhibitor of phosphotyrosine phosphatase, and 12-O-tetradecanoyl- phorbol-13-acetate (TPA), a known activator of protein kinase C, also stimulated DNA synthesis in these cells, suggesting that protein phosphorylation might be involved in the mechanism of action of mIL-3 and mGM-CSF. To assess this possibility, intact B6SUtA1 cells exposed for brief periods to mIL-3, mGM-CSF, and TPA were analyzed for changes in phosphorylation patterns using metabolic 32P-labeling and antibodies to phosphotyrosine. Both mIL-3 and mGM-CSF induced the serine-specific phosphorylation of a 68-Kd cytosolic protein, whereas all three agents stimulated the serine-specific phosphorylation of a 68-Kd membrane protein. Furthermore, mIL-3 stimulated tyrosine phosphorylation of the 68-Kd membrane protein, as well as of 140-, 90-, 55, and 40-Kd proteins. The 90-Kd protein was also tyrosine phosphorylated in response to mGM-CSF. These phosphotyrosine containing proteins were not detected in TPA-treated cells. These results indicate that protein phosphorylations on tyrosine and serine residues occur in B6SUtA1 cells following short-term incubation with mIL-3 or mGM-CSF and that most of these phosphorylation events are mediated by kinases other than protein kinase C (PkC). 相似文献
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Rudy W; Guckel B; Siebels M; Lindauer M; Meuer SC; Moebius U 《International immunology》1997,9(6):853-860
Introduction of co-stimulatory molecules like CD80 and CD86 represents a
means to augment the immunogenicity of tumor cells and to induce immune
responses directed at tumor antigens. Here we compared CD80- and
CD86-transfected human melanoma cells to induce primary immune responses by
their capacity to promote proliferation of human allogeneic resting T
lymphocytes. CD80- and CD86-transfected SkMel63 melanoma cells induced T
cell activation to a comparable degree, which was found to be independent
of the cell surface density of these co- stimulatory molecules.
Co-expression of CD80 and CD86 did not result in a synergistic increase in
T cell proliferation. Both CD80 and CD86 transfectants induced the
proliferation of isolated CD4+ or CD8+ T cells. Exogenous IL-2, IL-4 and
tumor necrosis factor-alpha respectively enhanced primary T cell
proliferation independent of CD80 or CD86 expression. Interestingly,
differential activities of CD80 and CD86 were observed following
stimulation of resting T cells in the presence of IL-12. Whereas IL-12
increased T cell proliferation in the presence of CD86-transfected melanoma
cells, it exhibited an inhibitory function in the presence of
CD80-expressing SkMel63 cells. Experimental evidence indicates that this
inhibitory effect was mediated by IFN- gamma since (I) IFN-gamma secretion
of stimulated T cells was augmented by IL-12, (II) exogenous IFN-gamma also
inhibited T cell proliferation induced by CD80- but not CD86-transfected
SkMel63 cells and (III) the inhibitory effect of IL-12 was blocked by an
anti-IFN-gamma mAb.
相似文献
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Background
A retrospective assessment of contrast enhanced computed tomography (CECT) scan findings in histopathologically proven cases of carcinoma of the gallbladder (GB) was performed to review its role in diagnosis, staging and assessment of surgical resectability.Methods
All the patients had been subjected to a standardised abdominal helical computed tomography scan. Orally administered iodinated contrast was used for opacification of bowel and dynamic intravenous injection of non-ionic iodinated contrast for studying the lesional enhancement and vascular structures.Results
The presence of focal or diffuse mass lesions in the gallbladder fossa, infiltration of a liver and second part of duodenum were the most reliable diagnostic features in carcinoma gallbladder. Regional spread was better delineated on CT scan as compared with ultrasonography.Conclusion
CT scan is an effective method for evaluating, characterizing and detecting the spread of GB carcinomas.Key Words: Gall Bladder, Carcinoma, Computed Tomography 相似文献79.
80.
Congenital heart lesions involving the right ventricular outflow tract (RVOT) are a common problem in paediatric cardiology. These patients need multiple surgical interventions in the form of valved conduits over a lifetime. Surgical re-valvulation was the standard treatment option until the introduction of percutaneous pulmonary valves over a decade ago. These valves can be used to prolong the lifespan of conduits and reduce the number of re-operations. The Melody® valve (Medtronic, Minneapolis, MN, USA) was introduced as the first dedicated percutaneous pulmonary valve. Percutaneous pulmonary valves can be implanted successfully and have the advantage of short hospitalisations. We describe the first three Melody® valve implantations in Africa. 相似文献