Investigations in this laboratory will continue to be directed toward development of knowledge on blood platelet function in normal hemostatis, their role in the pathogenesis of inherited and acquired bleeding disorders, and their contribution to vascular injury, thrombosis and atherosclerosis. Analytical, scanning and transmission electron microscopy, freeze-fracture, cytochemistry and immunocytochemistry combined with cyclic nucleotide, adenine nucleotide and prostaglandin biochemistry and advanced physiological techniques, including micropipette elastimetry and lumi-aggregometry, will be used to develop new information on these problems and related areas. Particular emphasis has been placed on achievement of six specific aims. New approahes to the study of membrane ultrastructure will be used to identify physical alterations in platelet membranes and membrane systems not evident previously. Giant platelets with normal function from patients with the May-Hegglin anomaly will permit study of platelet membrane deformability before and after activation and surface receptor mobility (capping and patching) for the first time. Freeze-fractue and other sophisticated technology will be used to solve basic problems presented by inherited disorders of platelet function. A new mechanism of membrane modulation regulating platelet activation and the phenomenon of disaggregation and reaggregation of irreversibly aggregated platelets were recently discovered in this laboratory. They offer excellent opportunities to gain new knowledge of platelet biochemistry and physiology. Megakaryocytes can be concentrated and purified. We will recover them from a dog model permitting in depth sutyd of each stage of maturation and use of the techniques of structural physiology. Accomplishment of these aims will allow us to gain the knowledge required to control or prevent hemorrhagic and thrombotic disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL011880-17
Application #
3334443
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1977-04-01
Project End
1987-01-31
Budget Start
1985-02-01
Budget End
1986-01-31
Support Year
17
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Rao, G H; Escolar, G; White, J R et al. (2001) Differential response of human and bovine platelets to bovine von Willebrand factor and vascular subendothelium. Platelets 12:150-5
Rao, G H; Peller, J D; White, J G (1997) Influence of ionized calcium on thrombin-induced down regulation of GPIb/IX receptors on human platelets. Thromb Res 85:23-31
White, J G; Rao, G H (1996) Aggregated-disaggregated, refractory platelets retain sensitivity to ristocetin. Thromb Res 84:253-66
Rao, G H; Parthasarathy, S (1996) Antioxidants, atherosclerosis and thrombosis. Prostaglandins Leukot Essent Fatty Acids 54:155-66
White, J G; Krumwiede, M D; Cocking-Johnson, D et al. (1996) Prelabeled glycoprotein Ib/IX receptors are not cleared from exposed surfaces of thrombin-activated platelets. Am J Pathol 149:629-38
Rao, G H; Peller, J D; Knopman, D S et al. (1996) Physiology and function of platelets from patients with Alzheimer's disease. Indian J Physiol Pharmacol 40:5-14
White, J G; Escolar, G (1996) Fate of the GPIb/IX receptor complex following activation of human platelets. Blood Coagul Fibrinolysis 7:262-5
White, J G; Krumwiede, M D; Cocking-Johnson, D J et al. (1996) Uptake of vWF-anti-vWF complexes by platelets in suspension. Arterioscler Thromb Vasc Biol 16:868-77
Escolar, G; Diaz-Ricart, M; White, J G (1995) Talin does not associate exclusively with alpha 2b beta 3 integrin in activated human platelets. J Lab Clin Med 125:597-607
White, J G; Krumwiede, M D; Cocking-Johnson, D et al. (1995) Retention of glycoprotein Ib/IX receptors on external surfaces of thrombin-activated platelets in suspension. Blood 86:3468-78

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