Platelet adhesiveness after blood donation

Platelet adhesiveness to glass was measured in healthy blood donors at the time of and eight days after donating 500 ml of blood. By a whole blood method a highly significant increase was found whereas by a method using platelet-rich plasma with added adenosine diphosphate there was only a slightly significant increase. The discrepancy suggested that changes in the red cell population might influence the results. Packed red cells from 19 blood donors obtained at the time of donation and eight days later were mixed with fresh pooled platelets from the same independent persons on each occasion. The whole blood platelet adhesiveness on this mixture showed an increase in every case after blood donation. It is postulated that the increased adhesiveness is influenced by the presence of young red cells.

Estimation of platelet adhesiveness on whole blood and platelet-rich plasma

Platelet adhesive tests were carried out in parallel on whole blood and platelet-rich plasma. A column of glass microspherules was used and adenosine diphosphate (ADP) was added to the platelet-rich plasma before passage through the column. Preliminary observations were made to show the effect of the containers and the anticoagulant used. The influence on platelets when stored at 4 degrees C and standing or mixing at room temperature was also assessed. The apparatus used to measure adhesiveness was designed to produce a constant rate of flow through a standard column of glass microspherules. Using both methods, adhesiveness was studied on 70 healthy blood donors. The result showed a significant correlation between the level of adhesiveness found with each technique.

Platelet adhesiveness in diabetes mellitus

Platelet adhesiveness has been assessed on whole blood from a series of 34 diabetics and 50 control subjects using adenosine diphosphate (A.D.P.) and by adherence to glass microspherules (ballotini). Using both techniques it was possible to demonstrate a significant increase in platelet adhesiveness in the diabetic patients.

Geotropic Response of Coleoptiles under Anaerobic Conditions

Coleoptiles of Avena sativa and Zea mays do not develop a geotropic response under anaerobic conditions.

Measurement of platelet adhesiveness including the use of diatomaceous silica (celite)

Methods of platelet adhesiveness to glass and celite have been developed. The technical merits of these methods have been compared with a method using adenosine diphosphate (ADP). The aspects of platelet stickiness measured by the various techniques may be somewhat different. Bearing this in mind, the reproducibility of the results using each of the three methods has been assessed on a series of healthy donors.

Assessment of Factor VII and Factor X

A method is described to separate factor VII from factor X in normal serum using electrophoresis in a polyvinyl chloride block. A potent source of factor X is obtained. This may be used in correction studies and for assessment of deficiencies of factor VII in patients.

A Study of the Defect in Thromboplastin Generation Produced by Concentrated Normal Platelets

This paper provides experimental evidence that high concentrations of normal platelets can produce a secondary deficiency of the serum factor IX when the tests are carried out under optimal conditions. The deficiency is due to absorption of factor IX by the platelets.