Effect of ATIII and HCII on inhibition of clotting activity by ISIS 2302 in a purified thrombin time assay. The clotting time for plasma-derived thrombin was determined as described in the legend of Fig 3, except that thrombin was added last to initiate the clotting time. The ISIS 2302 dose response was compared in the absence of inhibitor (•), with 500 nmol/L ATIII (○), or 250 nmol/L HCII (▪). Clotting times are expressed as the mean of triplicate determinations with error bars representing ±2 SD.