Summary
Fibrin formation from fibrin monomer (FM) complexes was studied in experimental animals
utilizing a previously described technique for quantitating fibrin deposition. A uniform
thrombin infusion was used to produce FM, fibrinolysis being inhibited by EACA. In
vivo complex formation between FM and 125I-fibrinogen was demonstrated chromatographically. A direct correlation was found
between blood fibrinogen concentration and fibrin deposition in organs. By contrast,
an inverse correlation between fibrinogen concentration and both enzymatic or non-enzymatic
fibrin formation was found in vitro. The mechanism by which fibrinogen potentiates
FM precipitation in vivo could not be explained by coprecipitation of fibrinogen in
the complex which could not be demonstrated. The inhibitory effect of HN2 on fibrin deposition despite the associated hyperfibrinogemia induced by this drug
is believed to underscore the importance of leukocytes in certain types of fibrin
deposition. A correlation between the leukocyte count and fibrin formation from FM
was also found. It was concluded that the risk of intravascular fibrin deposition
is increased by a raised fibrinogen level especially when accompanied by leukocytosis.