Western Illinois University: Macomb Campus
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Department of Physics
Physics Colloquium, Friday, November 9
Nov 6, 2012
Speaker: Dr. Naveen Jha
Date: Friday, November 9, 2012
Time: 4 PM
Room: 205 Currens Hall
Title: Insights into the thrombogenicity of Factor IXa: trace amounts of Factor IXa promote growth of clot size
Contamination of FIX with FIXa has been proposed to explain thrombotic adverse events in treated hemophilia B patients. The thrombogenic role of FIXa can be related to its slow inhibition in plasma. However, it remains unknown how FIXa exerts its thrombogenic effect. Here we used in vitro clot growth video-microscopy to investigate possible mechanisms of FIXa-mediated thrombogenicity. Human FIX deficient plasma was re-calcified and mixed with low-melting agarose to create a thin layer of plasma-gel, which on activation with TF-bearing lipid vesicle forms dose dependent clot size (not bigger than 1mm even with high TF concentration). On the other hand, the diffusion into the plasma gel of FXa or FIXa with a very small amount of TF induced dose-dependent initial clot growth followed by early termination of clot formation. Finally, FIXa premixed/activated with TF,TF-driven clot growth was followed by a steady-state large clot size. Steady-state rate of clot growth was directly proportional to plasma concentration of FIXa.
About the speaker:
Dr. Naveen Jha is a former MS student from the department of physics, WIU. Currently, he is working as an ORISE (Oak Ridge Institute for Science and Education) Fellow at the US Food and Drugs Administration laboratory in Bethesda (MD). His research interests fall into a wide variety of fields ranging from the study of blood clots to the photoluminescence of blue LED materials.