Role of Blood Platelets in Thromboembolism

Circulatory effects of 5‐hydroxytryptamine

“…Therefore, assuming that the normal wastage of platelets does release the active substance, only about 1-2,ug of serotonin is released per hour. In view of the magnitude of the doses required to cause vasoconstriction in the various vascular fields of the cat this makes it unlikely that the natural destruction of platelets throughout the body plays any part in the normal maintenance of arteriolar tone as has been suggested (Moolten et al 1949).…”

“…436C.R I suggested (Moolten, Vroman, Vroman & Goodman, 1949) that serotonin formed from platelets in the peripheral circulation acts locally as a factor in maintaining arteriolar tone.…”

Platelet aggregation in hyperadhesive states

“…7 , 16 The adherence of platelets to each other and to other surfaces is considered a fundamental step in the formation of hemostatic plugs and thrombiY A variety of methods have been developed to study the adhesive characteristics of platelets.n, 13,18 In Wright's technique, PRP is rotated in a specially designed glass bulb, and the percentage change in the platelet count is determined. Moolten and associates 13 passed whole blood through a glass wool filter and estimated the ratio of the platelet to the red cell loss. Hellem l l developed a method in which whole blood plasma was passed through a column containing a known weight of glass beads of standard size.…”

Effect of Vascular Catheterisation on Platelet Adhesiveness

“…This difference can prob ably be explained by the fact that the group contained relatively many patients with malignant diseases, i. e. conditions in which platelet adhe siveness has been described as increased [Moolten et al, 1949]. The change in haematocrit was presumably due to the plasma volume changes caused by the contrast medium [Bjork, 1966].…”