Influence of Certain Drugs on the Adhesiveness of Human, Rat, and Rabbit Blood Platelets in Vitro

Abstract

SummaryThis is a comparative study of the methods described by H. P. Wright and O’Brien for determining the adhesiveness of thrombocytes. An attempt is made to characterize and statistically correlate both techniques. With the aid of a Coulter Counter for thrombocyte counts, a normal range is presented for human, rat, and rabbit blood. Anticoagulants used are sodium citrate and Heparin.The influence of Cocaine and the Serotonin antagonist Ro 3-0837 was studied on these same substrates, to determine a pharmacological interference with results of either Wright’s test or O’Brien’s. Both drugs are found to induce a statistically significant increase in the “thrombocyte count” as compared to the corresponding controls. These effects are not real but to be attributed to an increase in particle count due to thrombocyte fragmentation as a consequence of drug application. There is no evidence for the claim that these drugs decrease the adhesiveness of thrombocytes.Numerical results of both tests often show a high and statistically significant correlation, especially following the addition of Ro 3-0837. Such is not true of individual blood samples to which no drug has been added. Evidentally, both tests are not specific for the same characteristic of normal blood platelets. But, when Ro 3-0837 is added, the breakdown of unstable platelets is induced; and the corresponding increase in count of thrombocyte fragments is expressed by both tests in the same fashion.

The "Membrane Capacitance" Aggregometer —a Method for Measuring Platelet Aggregation in Whole Blood

“…Horlick (1961) reported that the results of tests which he performed according to the Wright technique, differed from those obtained when the Moolten technique was used. Reber and Studer (1965) also pointed out that under certain circumstances the Born and Wright techniques may give false positive results, when drugs are tested for their anti-aggregative action, and concluded that both tests are not specific for the same property of blood platelets. Swank's screen filtration method can measure platelet response in whole blood (Swank et al, 1964a and1964b).…”

Circulating Platelet Aggregates and Thrombocytopenia Induced by Intravenous Infusions of Arachidonic and Lauric Acids in Guinea Pigs

“…Two platelets adhering to each other were not counted as aggregate. Total platelet counts were determined with a Coulter Counter Model B using the method of R eber and Studer [13]. Counts obtained during the infusions were expressed as percent of the initial counts.…”

Toxicological effects of Evans blue and Congo red on blood platelets

“…After the sample was taken, the arterial catheter was rinsed with 0.2 to 0.3 ml isotonic saline and dosed with a metal cap. Platelet counts were determined according to the method of REBER and STCrO~R [14] and expressed in percent of the initial counts.…”