The Effects Of Age And Thrombotic Stroke Upon Plasma Concentrations Of Fibrinogen Derivatives And Platelet Release

An investigation has been made of the activation of coagulation and fibrinolytic systems and platelets in normal individuals and in patients who have had cerebral infarction probably caused by thromboembolism. Thrombin and plasmin activities and platelet releasing stimuli were measured using double antibody techniques directed towards fibrinopepti.de A (FpA), fibrinogen fragment Bβl-42 and β thromboglobulin (βTG), respectively. Normal healthy laboratory controls' (n = 20) of mean age 29 yr, range 18-46, had mean FpA, Bβ 1-42 and βTG plasma concentrations of 1.06, 1.59 and 0.80 pmol/ml respectively. 95% of these normal results were within the range 1.50, 3.50 and 1.30 pmol/ml, respectively. Patients (n = 47) who had had computer assisted tomographical demonstrable stroke at least 1 month, but mostly greater than 1 yr, prior to examination had mean FpA, B β l-42 and βTG levels of 2.81, 4.44 and 2.09 pmol/ml. Some of these patients (n = 15) received sulphinpyrazone (800 mg daily) and their plasma levels were not appreciably different, 3.17, 5.48 and 2.18 pmol/ml respectively. The age of all patients, mean 65 yr, range 53-83, was considerably higher than the laboratory controls and therefore apparently healthy age and sex matched controls (n = 14) were studied. Mean FpA, Bβ 1-42 and βTG of this older control group were 2.1, 3.0 and 1.48 pmol/ml, respectively. It is concluded that (a) in normal apparently healthy individuals plasma concentrations of FpA, Bβ 1-42 and βTG rise with age, suggesting increased activation of coagulation and fibrinolytic systems and platelets (b) following thrombotic stroke the three systems are further activated and remain so for many months (c) sulphinpyrazone does not alter this activation.