Polyacrylamide-silastic surfaces

Thrombotic Events on Grafted Polyacrylamide—Silastic Surfaces as Studied in a Baboon... 

Laser Light Scattering Detection of Microemboli. To elucidate the mechanism of platelet destruction by grafted polyacrylamide-Silastic surfaces, an optical scattering technique was developed (20) to observe and quantitate the sizes and size distributions of microaggregates in blood produced within the AV baboon shunt. Presumably, any such flowing microaggregates represent platelet microemboli. 

Title Thrombotic Events on Grafted Polyacrylamide-Silastic Surfaces as... 

Figure 7a. ESC A C Is spectrum of the luminal surface of polyacrylamide-Silastic tubing in the dehydrated state.

Table II shows the effect on platelet consumption of increasing lengths of the polyacrylamide-Silastic tubing. The acrylamide surface is much more destructive to platelets than is the Silastic surface. Table II also shows that platelet consumption increases linearly with shunt area for both the polyacrylamide-Silastic shunts.

A series of shunts with radiation and ceric ion-initiated grafts of polyacrylamide on the luminal Silastic surface, and having water contents varying between 51-83% were also studied. Table III shows these data. The platelet consumption increases linearly with the gel water, such that the ratio of platelet consumption to graft water content remains relatively constant. 

Figure 12. Rates of production of thromboemboli volume ( 3Is) and equivalent platelet consumption by embolization (platelets/day) vs. surface area for two biomaterials Silastic (bottom) and polyacrylamide-Silastic (top). The equivalent steady-state platelet consumption is (3.0 0.2) x 108 (platelets day-cm2) for polyacrylamide-Silastic and (0.8 0.1) X 108 (platelets day-cm2) for Silastic.

Because fibrinogen remains at the gel top in the electrophoresis system used here, we cannot assess its importance because staining artifacts frequently occur at the gel top. However, adsorption of 125I-fibrinogen to polyacrylamide-Silastic shunt surfaces from baboon blood in vivo is much greater than adsorption to Silastic shunt surfaces (46). 

---