Aβ-influenced clots are resistant to lysis by plasmin but not trypsin. (A) Preformed clots prepared as described in “Clot turbidity analysis” with or without 5μM Aβ₄₂ were overlaid with 250nM plasmin. (B) Half-lysis was significantly slower in clots containing Aβ (P = .0001). (C) Preformed clots as in panel A were overlaid with 1μM trypsin. (D) There was no significant difference between half-lysis times of control and Aβ clots (P = .12).