Table 2.

Cleavage of ULVWF-platelet strings by rhADAMTS-13

	Before rhADAMTS-13	2 min after rhADAMTS-13	3 min after rhADAMTS-13	4 min after rhADAMTS-13
Histamine	119 ± 17.1	25 ± 12	3 ± 3	1 ± 1
Stx-1	112 ± 28	34 ± 9	21 ± 7	12 ± 6
Stx-2	122 ± 43	38 ± 15	24 ± 11	11 ± 4

The number of ULVWF-platelet strings secreted by HUVECs stimulated with 20 mM histamine or 10 nM Stx-1 or Stx-2 for 10 minutes prior to the experiment was quantified 2 minutes after beginning the perfusion of washed platelets in buffer over the previously stimulated cells. (No additional histamine or Stx was added to the washed platelet perfusate.) After counting the ULVWF strings, rhADAMTS13 was added to the washed platelets in buffer, and the perfusion was continued for another 10 to 15 minutes with string counting in 20 fields or photographing of the same field every 1 to 2 minutes.