SummaryCongenital deficiency of Fibrin Stabilizing Factor (FSF) is the cause of both pathological haemostasis and poor wound healing. Experiments with fibroblast cultures were carried out to characterize the latter. Growth of the cultures in the patient’s plasma was quantitatively and qualitatively inferior as compared with the growth in normal control plasma, which contained FSF. Only by addition of normal plasma and purified FSF the poor cell growth was corrected. The necessity of fibrin present in the first stage of wound healing and possible modes of action of FSF in haemostasis and wound healing are discussed.

No abstract

SummaryHuman fibrinogen was subjected to limited proteolytic attack by thrombin, batroxobin or Agkistrodon contortrix thrombin-like enzyme, yielding desAB-, desA- or desB-fibrin monomers, respectively. Turbidity curves demonstrated that, with all three enzymes, the polymerization process was strongly accelerated by increasing the calcium concentration from 10−5 M to 10−4 M. Synthetic peptide Gly-His-Arg (5 mM), an analogue of the aminoterminal sequence of fibrin β-chain, inhibited aggregation of desB-fibrin monomers at physiological calcium concentration whereas it enhanced aggregation of desA- and desAB-fibrin monomers at calcium concentrations below 10−4 M. On the other hand, Gly-Pro-Arg (1 mM) corresponding to the amino-terminus of fibrin α-chain, dramatically inhibited aggregation of both desA- and desB-fibrins, but it only moderately affected the polymerization of thrombin-induced monomers. We conclude that the observed effects of Gly-Pro-Arg and Gly-His-Arg are not due solely to their competition with fibrin amino-termini for the respective binding sites in the D-domain, but rather reflect conformational changes in fibrin monomers which affect the polymerization process.

No abstract