Table 1.
Rate Parameters Descriptive of FXII Autoactivation in Human Plasma
| Hydrophilic Procoagulant | Hydrophobic Procoagulant | |||||
|---|---|---|---|---|---|---|
| WF12o μg/mL | A ×10−3 PEU/mL·sec | B ×10−1 1/sec (%R2, N=8) | C PEU/mL×10−3 (N=4) | A ×10−3 PEU/mL·sec | B ×10−1 1/sec (%R2, N=8) | C PEU/mL×10−3 (N=4) |
| 30 (1X) (endogenous) | 1.07±0.22 | 1.43±0.29 (84.0) | 7.53±0.13 | 0 | 0 | 0.02±0.01 |
| 37.5 (1.25X) (endogenous +7.5 exogenous) | 2.63±0.42 | 2.35±0.37 (89.0) | 11.2±0.31 | 0.11±0.01 | 1.64±0.18 (92.2) | 0.66±0.05 |
| 45 (1.5X) (endogenous +15 exogenous) | 4.79±0.47 | 3.15±0.30 (94.7) | 15.2±0.28 | 0.56±0.08 | 3.00±0.39 (82.4) | 1.88±0.12 |
| 52.5 (1.75X) (endogenous +22.5 exogenous) | 4.90±0.44 | 2.94±0.24 (95.2) | 16.7±0.6 | 1.21±0.15 | 4.24±0.50 (82.5) | 2.85±0.12 |
| 60 (2X) (endogenous +30 exogenous) | 5.62±0.58 | 3.49±0.34 (93.4) | 16.1±0.6 | 1.57±0.21 | 4.54±0.60 (74.7) | 3.45±0.05 |
Notes: WF12o is the nominal FXII concentration assuming 30 μg/mL normal physiologic concentration. Procoagulants = 150 mm2 nominal surface area of water-wettable (hydrophilic) and silanized-glass (hydrophobic) particles (see Methods and Materials). Error in parameter A=B·C computed by propagation of error; error in parameter B is the standard error of the fit to Eq. 5 of Appendix I; error in parameter C the standard deviation of the mean of N=4 steady-state FXIIa concentrations (see Results).