Image of the Week

03/03/2003 – In this confocal laser scanning microscope image, cultured human umbilical vein endothelial cells were stained with propridium iodide that is a marker of the DNA in the nucleus (red), and with a fluorescein-conjugated (green) antibody directed against the procoagulant protein known as von Willebrand factor (vWf). The large green rods represent the specialized intracellular organelles called Weibel-Palade bodies, which serve to store vWf until it is needed. These cells rapidly release vWf in response to the presence of various mediators of blood vessel wall injury, at which time vWf is secreted into the circulation and onto the endothelial cell surface. The release of vWf serves to promote platelet adhesion and thrombosis (blood clotting). There are forms of bleeding disorders in which people lack sufficient amounts of vWf, leaving them with the inability to form stable blood clots. Submitted by Dr. Tom Podor.

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