We present a new method for the geometric reconstruction of elastic surfaces simulated by immersed boundary with goal simulating motion and interactions cells in whole blood. Our uses parameter-free radial basis functions high-order meshless parametric point clouds force computations required method. This numerical framework allows us to consider effect endothelial geometry red blood cell on pl...

Abstract Thrombospondin-1 (TSP-1) is released by platelets upon activation and can increase platelet activation, but its role in hemostasis vivo unclear. We show that TSP-1 a critical mediator of promotes modulating inhibitory cyclic adenosine monophosphate (cAMP) signaling. Genetic deletion did not affect vitro, models thrombosis showed TSP-1–deficient mice had prolonged bleeding, defective th...

This study described the binding of platelet plasma membranes to either control or thrombin-activated platelets. Glycoproteins in plasma membranes isolated from human platelets were labeled by oxidation with periodate followed by reduction with [3H]NaBH4. Labeled membranes were incubated with either control or thrombin-activated platelets. The amount of membranes bound was measured by separatin...

Platelet function and the interaction of platelets with human fibrinogen have been studied following degradation of membrane glycoproteins by chymotrypsin. Washed human and rabbit platelets were treated with a-chymotrypsin (1-50 U/mI), which cleaved glycopeptides from membrane glycoproteins without causing aggregation or release of granule contents. Chymotrypsin removed a large percentage of th...

Approximately 6% of dog platelets are positive for staining with thiazole orange, a dye frequently used to stain ribonucleic acid. In this report, thiazole-orange positivity is shown to mark platelets that are less than 24 hours old. Dog platelets were derivatized in vivo with N-hydroxysuccinimido biotin such that greater than 95% of all platelets were biotinylated. Newly synthesized, nonbiotin...

The role of fibrinogen in interplatelet recognition during aggregation was examined by combining two cell types: fresh platelets (in limiting density) activated by thrombin or A231 87. and formaldehyde-fixed platelets. bearing crosslinked fibrinogen. The fixed platelets did not aggregate by themselves. nor with resting platelets, but were capable of interacting with activated platelets and of p...

Fibrinogen is a cofactor in the aggregation of human platelets, and is required for ADP-induced aggregation of washed platelets; however, exogenous fibrinogen is not required for ADP-induced aggregation of washed platelets from rabbits or rats. Because with human platelets the cell adhesion peptide, Arg-Gly-Asp-Ser (RGDS), inhibits aggregation and the binding of 125I-fibrinogen to ADP-stimulate...

Platelets promote metastasis and angiogenesis, but their effect on tumor cell growth is uncertain. Here we report a direct proliferative effect of platelets on cancer cells both in vitro and in vivo. Incubation of platelets with ovarian cancer cells from murine (ID8 and 2C6) or human (SKOV3 and OVCAR5) origin increased cell proliferation. The proliferative effect of platelets was not dependent ...

The authors have investigated the ability of platelets to enhance factor Xa-catalyzed activation of factor VII. Unstimulated platelets were without effect, whereas freeze/ thawed platelets substantially enhanced activation. Antifactor V antibodies did not diminish the enhancement. Platelets activated by thrombin. collagen, or calcium ionophore A23187 also enhanced factor Xa-catalyzed activation...

1Program in Human Molecular Biology and Genetics and 2Department of Surgery, University of Utah, Salt Lake City; 3Department of Nanoscale Imaging of Cellular Dynamics, Courant Research Centre Nano-Spectroscopy and X-Ray Imaging, University of Göttingen, Göttingen, Germany; 4Department of Physics and Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA; 5Division...