Browsing by Author "Forouzan, Omid"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Histamine reduces GPIb?-mediated adhesion of platelets to TNF-?-activatedvascular endothelium(Thrombosis Research, 2013) Brown, Theodore P.; Forouzan, Omid; Shevkoplyas, Sergey S.; Khismatullin, Damir B.Histamine and tumor necrosis factor-? (TNF-?) are critical mediators of acute and chronic inflammation that are generated by mast cells and macrophages in atherosclerotic lesions or systemically during allergic attacks. Both of them induce activation of vascular endothelium and thus may play a role in thrombosis. Here we studied the interplay between histamine and TNF-? in glycoprotein (GP) Ib?-mediated platelet adhesion to cultured human vascular endothelial cells under static and shear flow conditions. The stimulation of endothelial cells with histamine or TNF-? increased the number of adherent or slow rolling GP Ib?-coated microbeads or washed human platelets. However, the application of histamine to endothelium pre-activated by TNF-? inhibited GP Ib?-mediated platelet adhesion. These effects were found to be associated with changes in the concentration of ultra large von Willebrand factor (ULVWF) strings anchored to endothelium. The results of this study indicate that histamine released during mast cell degranulation may cause or inhibit thrombosis, depending on whether it acts on resting endothelial cells or on cells pre-activated by other inflammatory stimuli.Item PDMS Well Platform for Culturing Millimeter-Size Tumor Spheroids(Biotechnology Progress, 2013) Ratnayaka, Sithira H.; Hillburn, Taylor E.; Forouzan, Omid; Shevkoplyas, Sergey S.; Khismatullin, Damir B.Multicellular tumor spheroids are widely used as in vitro models for testing of anticancer drugs. The advantage of this approach is that it can predict the outcome of a drug treatment on human cancer cells in their natural three-dimensional environment without putting actual patients at risk. Several methods were utilized in the past to grow submillimeter-size tumor spheroids. However, these small models are not very useful for preclinical studies of tumor ablation where the goal is the complete destruction of tumors that can reach several centimeters in diameter in the human body. Here, we propose a PDMS well method for large tumor spheroid culture. Our experiments with HepG2 hepatic cancer cells show that three-dimensional aggregates of tumor cells with a volume as large as 44 mm3 can be grown in cylindrical PDMS wells after the initial culture of tumor cells by the hanging drop method. This is a 350 times more than the maximum volume of tumor spheroids formed inside hanging drops (0.125 mm3 ).