Physiological studies on fibrin network structure.

Networks were developed in fibrinogen solution under pathophysiological conditions of clotting and their permeability and turbidity were measured. Mass-Length ratio of fibrin fibres (a measure of fibre thickness) was derived from two independent methods based on turbidity (mu T) and permeability (mu P). Both mu T and mu P increased as thrombin concentration was decreased. Data are in agreement with the concept that the fibrin network develops initially as a mesh of protofibrils. Fibrin monomer generated subsequently is incorporated into the existing network making individual fibres thicker. Consequently, slow fibrin monomer generation promotes thicker fibres. When the concentration of thrombin or fibrinogen was altered systematically, mu T and mup were found to mirror each other except when the fibrinogen concentration was increased at low thrombin concentrations. This breakdown between the two derivations of mass-length ratio is discussed in terms of the two network model.