The recent Food and Drug Administration (U.S.) approval of a new blood preservative (CPDA-1) which contains adenine not only introduces a new blood product into the American blood banking system, but also heralds the advent of novel approaches to blood product preservation. The use of adenine to effect maintenance of red cell adenosine triphosphate (ATP), and hence to prolong storability, has a well-founded biochemical rationale. Effects of adenine on red cell metabolism are generally well understood, but effects on other blood components have not been fully delineated. The efficacy of adenine preservatives in enhancing the duration of red cell storage appears to outweigh the small risk of toxicity from free adenine. Clinical use of millions of units of adenine-preserved blood in Europe during more than a decade has resulted in only one report of possible adenine toxicity. Marginal acceptability of 24-hr 51Cr red cell recovery of packed red cells stored for 35 days in CPDA-1 has stimulated development and evaluation of an improved preservative (CPDA-2) which may extend blood storability beyond 35 days. A heightened awareness of the hematological consequences of prolonged storage has come with the extension of blood storage beyond 21 days. The concepts of component-specific preservation systems and optimal preservation systems have emerged as a result of experimentation on adenine preservatives. While the influence of adenine preservatives on American blood banking is yet to become manifest, the ultimte impact of adenine on blood preservation may be the development of novel systems which optimally preserve specific blood components at the option of the user.

Glycoproteins have been discovered to be important to platelet function both in normal and pathological states. We have studied membrane glycoprotein patterns in 16 patients with various myeloproliferative disorders. There was an abnormal ratio of glycoprotein I:glycoprotein IV in patients with myeloproliferative disease compared with controls. There was no discernible correlation between glycoprotein pattern and aggregation response or platelet count, but patients with megathrombocytes had higher values for glycoprotein IV than those without megathrombocytes. These experiments suggest that patients with myeloproliferative disorders may have alterations in membrane glycoproteins that could alter platelet function.

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Extension of the time within which whole blood may be separated into components offers logistic advantages for the operation of remote mobile drawing teams. We evaluated the effect of an 8-hour hold of whole blood at room temperature before preparation of components. Plasma coagulation activity and opsonic factor content were studied in 14 units drawn into the anticoagulant-preservative solution citrate-phosphate-dextrose-adenine (CPDA-2). At the time of collection, an additional 7-ml aliquot was drawn into 1 ml of CPDA-2, the plasma separated and frozen immediately. Components were prepared from whole blood units allowed to rest undisturbed at 22 +/- 1 degrees C for 8 hours. After 8 hours, a significant decrement of about 10 percent was found in the concentration of fibrinogen, plasminogen, fibronectin, and activity of Factor V. Factor VIII activities (VIIIAHF and VIIIAGN) were not significantly different after 8 hours. Our results indicate that room temperature storage for 8 hours before component processing has minimal effects on potentially labile plasma protein factors using CPDA-2 anticoagulant-preservative solution.

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