A COMPLETE PLATELET SYSTEM FOR METABOLIC STUDIES - PURE, DEFINED, ANDVIABLE OVER 8 HOURS

We have been using a human platelet preparation to investigate various aspects of cellular metabolism. These experiments require a pure, qua ntitated platelet preparation that is viable for up to 8 h. The purity of the preparation has previously been characterized and we have now assessed its viability over 8 h and developed a simple spectrophotomet ric counting method. This method of counting results in estimations th at are within 6% of those from an electronic cell counter (Coulter). P ure platelets stored in a Hepes physiological saline were resuspended periodically in autologous plasma to assess function over 24 h. The pl atelets consumed oxygen, changed shape, aggregated, and released dense granule ATP at all times. There was a slow and linear decrease in the various processes with time, ranging from 1.7% per hour for oxygen co nsumption to 3.8% per hour for percentage aggregation. The preparation is therefore not stable, but the changes with time are small and defi ned and it represents a useful system for the study of platelet and ce ll biology. (C) 1995 Academic Press, Inc.