Contact Activation[1] 8. August 2004

Determination of Hageman-Factor (FXIIa) and kallikrein activity after plasma contact with foreign surfaces.

HEPES/ NaCl Buffer

50mM     HEPES

120mM    NaCl

pH 7.4

Reagent solution for F XIIa + Kallikrein

125µg/mLZ-Lys-Phe-Arg-pNA x 2HCl (Z-KFR-pNA)   Merck 233500

in HEPES/NaCl buffer

Reagent solution for F XIIa

dto

200 KIU/mL (final) Aprotinin                    Sigma 10818

Sample material

Plasma (citrate plasma is good)

Standard

Mix plasma with kaolin (any amount is excess)   Sigma K7375

Incubate 10min+

Use as 100% standard, make dilution row with untreated plasma

Measurement

200µl    Reagent solution

10µl     Plasma or standard

read kinetic over 10min at l = 405nm

Note

The substrate is not in a saturation concentration.

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[1]J.M. Grunkemeier, et al., Hemocompatibility of treated polystyrene substrates: Contact activation, platelet adhesion, and procoagulant activity of adherent platelets. J Biomed Mater Res, 1998. 41: 657-70.