Studies on the Clot-Promoting Activity of Glass

Abstract

Although the clot-promoting activity of foreign surfaces has been the subject of many studies during almost a century (1) its nature is not yet understood. While glass has been thought to activate platelets (2), recent studies have mostly been concerned with the effect of glass on plasma clotting factors.Quick maintained that contact with glass activates the precursor of prothrombin, prothrombinogen (3) as well as the precursor of plasma thromboplastin, possibly antihemophilic factor A (4). Conley and his associates (5-8) have reported that contact with glass markedly shortens the clotting time of silicone prepared "platelet free" plasma and increases its prothrombin utilization. They concluded that glass activates "plasma thromboplastin," a constituent residing in the globulin fraction. Biggs, Douglas, and Macfarlane (9) stated that the increased clotting activity developed in plasma by contact with glass is probably due to a change in Christmas Factor (PTC, antihemophilic factor B). Alexander, de Vries, and Goldstein (10) observed that contact with glass during clotting of blood favors the evolution of SPCA (convertin, Factor VII). Rapaport, Aas, and Owren (11) showed that exposure to glass markedly increases the activity of proconvertin as well as of PTC. Other communications (12, 13) attributed the clot-promoting activity of glass to removal of lipid or protein inhibitors of the first phase of coagulation, i.e., the evolution of thromboplastic activity.In the present study it is shown that a plasma clotting factor other than those mentioned above may be activated by contact with glass. MATERIALS AND METHODSCollection of blood. Human venous blood was collected by the two-syringe method using silicone coated needles and glassware.

The Formation and “Decay” of Xlla

“…This might be termed an effect of difference in critical micelle concentration. In accord with the observations and conclusions of Shafrir (11) and Didisheim (3) , the non-essentiality of ionic calcium was confirmed by the formation of XIIa in the presence of citrate as well as EDTA.…”

A Special Haemophilic Syndrome

“…Eluates from glass, on the other hand, had a very definite correcting effect on our patients plasma, but not on plasma from a case of haemophilia B. Factor IX does not seem to belong to the group of factors ac tivated by glass contact (38).…”

Thromboplastin Formation

“…They postulated that glass adsorbed an inhibitor which was attached to Hageman factor in freshly-shed blood, thus freeing the factor in activated form. Others, in cluding Johnston's group and Shafrir & de Vries (18) have felt that the func tion of glass was to increase an activity rather than to adsorb an inhibitor and by 1961 Ratnoff came to agree with this view. The analysis by Biggs et al in 1958 (19), of four new cases, three of which were felt to have PTA deficiency and one Hageman trait, led to their hypothesis that "surface activation" involves at least two steps: first, activation of Hageman factor by glass; and, second, activation of PTA by the activated Hageman factor.…”