Roger Procyk

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The porosity, fiber dimension and architecture of fibrin gels formed in recalcified plasma on addition of thrombin are, within a certain range of thrombin concentrations, determined by the initial rate of fibrinogen activation. Furthermore, the initial network formed in this range creates the scaffold into which subsequently activated fibrinogen molecules(More)
Native fully hydrated fibrin gels formed at different fibrinogen and thrombin concentrations and at different ionic strengths were studied by confocal laser 3D microscopy, liquid permeation and turbidity. The gels were found to be composed of straight rod-like fiber elements that often came together at denser nodes. In gels formed at high fibrinogen(More)
Expression vectors containing full-length cDNAs for each of the human fibrinogen chains were constructed. COS-1 cells were transfected with single vectors, mixtures of two, or with all three vectors and stable cell lines selected. Cells transfected with single vectors, or with mixtures of any two vectors, expressed the appropriate fibrinogen chains but did(More)
The elastic modulus (G') of factor XIIIa induced fibrinogen gels was found to be substantially lower than the G' of fibrin gels that were formed by clotting fibrinogen with thrombin. The addition of fibronectin and/or the reducing reagent dithiothreitol (DTT) to the factor XIIIa coagulation mixture led to the formation of a weaker gel structure, while the(More)
In solutions containing fibrinogen and fibronectin, factor XIIIa catalyzes the formation of two types of crosslinked polymers: hybrid oligomers consisting of equimolar amounts of fibrinogen and fibronectin, and fibrinogen oligomers. The two types of oligomers are produced in amounts proportional to the starting concentration of fibronectin and fibrinogen in(More)
Factor XIII catalysis proceeds via formation of thioester acyl enzyme intermediate involving an active site cysteine residue at position 314. The contribution of other residues to catalysis has not been established. Earlier studies of the pH dependence of factor XIII activity suggested the existence of a putative active site histidine. We used chemical(More)
A new chimeric plasminogen activator with high fibrin affinity was designed to bind fibrin and to initiate clot destruction, following activation by thrombin. The chimeric activator, 59D8-scuPA-T, was made from the Fab fragment of an anti-fibrin antibody (59D8) and a C-terminal portion of a thrombin-activable low molecular weight single-chain urokinase(More)
The association of factor XIII a-subunits with fibrin was characterized using recombinant human placental factor XIII (rFXIII) and native fully hydrated fibrin clots formed from purified fibrinogen and thrombin. Binding was assessed using small columns containing fibrin and perfusing them with radioiodinated rFXIII. Results show that thrombin activation of(More)
Protein synthesis in rat liver in vivo was measured between 0 and 72 h after administration of a non-lethal dose of cycloheximide. There was a period of inhibition of [3H]leucine incorporation into both intra- and extra-cellular proteins at 2 h after administration of the drug, which was followed by a recovery phase in which amino acid incorporation varied(More)