51 research outputs found
Highly sensitive proximity mediated immunoassay reveals HER2 status conversion in the circulating tumor cells of metastatic breast cancer patients
<p>Abstract</p> <p>Background</p> <p>The clinical benefits associated with targeted oncology agents are generally limited to subsets of patients. Even with favorable biomarker profiles, many patients do not respond or acquire resistance. Existing technologies are ineffective for treatment monitoring as they provide only static and limited information and require substantial amounts of tissue. Therefore, there is an urgent need to develop methods that can profile potential therapeutic targets with limited clinical specimens during the course of treatment.</p> <p>Methods</p> <p>We have developed a novel proteomics-based assay, Collaborative Enzyme Enhanced Reactive-immunoassay (CEER) that can be used for analyzing clinical samples. CEER utilizes the formation of unique immuno-complex between capture-antibodies and two additional detector-Abs on a microarray surface. One of the detector-Abs is conjugated to glucose oxidase (GO), and the other is conjugated to Horse Radish Peroxidase (HRP). Target detection requires the presence of both detector-Abs because the enzyme channeling event between GO and HRP will not occur unless both Abs are in close proximity.</p> <p>Results</p> <p>CEER was able to detect single-cell level expression and phosphorylation of human epidermal growth factor receptor 2 (HER2) and human epidermal growth factor receptor 1 (HER1) in breast cancer (BCa) systems. The shift in phosphorylation profiles of receptor tyrosine kinases (RTKs) and other signal transduction proteins upon differential ligand stimulation further demonstrated extreme assay specificity in a multiplexed array format. HER2 analysis by CEER in 227 BCa tissues showed superior accuracy when compared to the outcome from immunohistochemistry (IHC) (83% vs. 96%). A significant incidence of HER2 status alteration with recurrent disease was observed via circulating tumor cell (CTC) analysis, suggesting an evolving and dynamic disease progression. HER2-positive CTCs were found in 41% (7/17) while CTCs with significant HER2-activation without apparent over-expression were found in 18% (3/17) of relapsed BCa patients with HER2-negative primary tumors. The apparent 'HER2 status conversion' observed in recurrent BCa may have significant implications on understanding breast cancer metastasis and associated therapeutic development.</p> <p>Conclusion</p> <p>CEER can be multiplexed to analyze pathway proteins in a comprehensive manner with extreme specificity and sensitivity. This format is ideal for analyzing clinical samples with limited availability.</p
Effects of surface heat transfer and spatial property dependence on the optimum performance of a thermoelectic heat pump
Ph.D.J. Edward Sunderlan
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Regulation of tumor necrosis factor and interferon-gamma release from lymphokine-activated killer cells.
Peripheral blood lymphocytes cultured in interleukin 2 (IL-2) acquire the ability to lyse tumor cell targets in a non-major histocompatability complex (MHC) restricted manner. These lymphokine activated killer (LAK) cells release tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN-Ī³) in culture and when stimulated by interaction with tumor cells in vitro. The capacity of several suppressive factors to affect the release of TNF and IFN-Ī³ from LAK cells which have been stimulated with K562 erythroleukemia cells was investigated. A number of agents known to inhibit mononuclear phagocyte secretion of TNF were tested, including prostaglandin Eā (PGEā), alpha-globulins and the synthetic protease inhibitor tosyl-arginine methyl ester (TAME). The alpha globulins and TAME are thought to suppress TNF release from monocytes by inhibiting proteolytic cleavage of the cytokine from the cell surface. The addition of PGEā, whole plasma alpha globulins, purified alpha-1-acid glycoprotein, and TAME inhibited TNF and IFN-Ī³ release in a concentration dependent manner. These inhibitory factors appear to act directly on the lymphocytes to suppress cytokine secretion, as the presence of monocytes or metabolically active tumor cells was not required. The effects of alpha-1-acid glycoprotein on LAK cells were also investigated. The addition of this alpha globulin fraction inhibits the incorporation of Ā³[H] thymidine by LAK cells stimulated with tumor cells, and results in a detectable decrease in TNF mRNA. The capacity of alpha-1-acid glycoprotein to suppress the release of TNF production also resulted in an inhibition of LAK cell generation which was reversed by the addition of exogenous TNF. In contrast to their suppressive effect on peripheral blood monocytes, the protease inhibitors alpha-1-antitrypsin and alpha-2-macroglobulin enhanced TNF secretion from LAK cells exposed to leukemia cells. Analysis of cell surface TNF expression by fluorescence activated cell sorting (FACS) suggest that the observed differences in regulation reflect the capacity of particular phenotypes to express TNF as a transmembrane molecule. The data presented here indicate that the regulation of TNF release by LAK cells stimulated with tumor cells differs significantly from that previously observed in monocytes and suggest a regulatory role for alpha-1-acid glycoprotein in TNF secretion by LAK cells
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Scoping study of the effects of core blockage on loss-of-coolant accident blowdown behavior in a PWR
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Flow film boiling heat transfer correlations: a parametric study with data comparisons
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