Platelet factor 4 plasma levels at rest and after exercise in patients with recent myocardial infarction.
Plasma levels of platelet factor 4 (PF 4) were determined in 30 patients with recent acute myocardial infarction. Comparisons were made with the levels in 26 age-matched controls. In another 15 patients, also with recent myocardial infarction, PF 4 plasma levels were determined before and immediately after a standardized exercise stress test. At rest, none of the patients had elevated PF 4 levels. Only one patient demonstrated an increase after exercise. These findings are in conflict with some recent reports. The importance of age-matched controls, the hazard of in vitro platelet activation and the possible effect of beta-blocking and calcium-antagonistic drugs on PF 4 plasma levels is discussed below.
D000368:Aged; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D005082:Physical Exertion; D011863:Radioimmunoassay; D012146:Rest
D002118:Calcium