Protein-coated surfaces, platelet

Several investigators (9, 21, 22) have found that foreign surfaces, when exposed to blood, adsorb plasma proteins. Since platelet adhesion to the surface is the first observable event occurring in clotting on foreign surfaces, and since platelets are known to participate in hemostasis and coagulation, the indication is that platelet adhesion onto the plasma protein-coated surface plays a major role in the in vivo initiation of thrombus formation on foreign surfaces. 

The thrombotic response (the time vs. platelet and fibrin deposition pattern) for uncoated PVC (shown in Figures 2 and 3) is a response to PVC that is coated with a complex mixture of proteins in the initial seconds of blood contact. Therefore, at least part of the thrombotic response on PVC is generated by a complex protein-coated surface composed of many proteins adsorbed in various conformations, including serum albumin, 7-globulin, fibrinogen, and fibronectin. However, these four proteins account for only 75% of the total protein in plasma and, therefore, significant amounts of other proteins not accounted for by our measurements may be adsorbed to the test surface. 

Thrombotic Response to Protein-Coated Surfaces. Overview. Although Figures 2, 3, 5, 6, and 8-11 show fibrin(ogen) and platelet responses to many different surfaces, all of the curves have a similar appearance. At the first datum of 2 min, an initial amount of deposition was gener-... 

Aspects of Platelet Adhesion to Protein-Coated Surfaces... 

The work to be discussed here deals with platelet adhesion to protein coated surfaces. The protein coating, the cells on the surface and the moving fluid adjacent to the surface may be viewed as a system of interacting components. Flow is an important feature of this system since it brings new protein and cells to the system, augments the transport of cells to the surface and can cause the detachment of adherent cells. Each component of the system may influence the conditions of the other components. The variation of the surface concentrations of proteins on a solid substrate continues to be studied and remains a key area of interest. However, the action of immobilized cells on the substrate needs to be examined more carefully as well as their contribution of secreted substances to the fluid phase adjacent to the substrate and to the substrate protein itself Red cells, platelets and white cells may also adhere and detach from the substrate changing its make-up by yet another mechanism. 

Perfuse cells (e.g. THP-1 monocytic cells, leukocytes, tumor cells, protein-coated beads, etc.) over surface-bound platelets, either in the presence or absence of a platelet antagonist (see above), at the desirable flow rate for prescribed periods of time, THP-1 cell binding to immobilized platelets is monitored in real time, and recorded on videotape. 

Skarja, G. A., Brash, J. L., Bishop, R, and Woodhouse, K. A. (1998). Protein and platelet interactions with thermally denatured fibrinogen and crosslinked fibrin coated surfaces, BigmgiSJTols, 19,2129-2138. 

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