Summary
Streptokinase or glycerol activated human fibrinolysin was added to human plasma and
the enzyme action was stopped by the addition of epsilon amino-caproic acid at different
time intervals. The clottable fibrinogen content of the mixtures was determined by
diluting the plasma with either physiological saline or distilled water, both containing
thrombin or thrombin plus calcium chloride. It was found that before the addition
of fibrinolysin the values in distilled water containing calcium chloride were higher
than the respective values in plain saline or in saline containing calcium chloride.
The drop in clottable fibrinogen after the addition of fibrinolysin was more pronounced
when the determinations were performed in plain distilled water. Thus, a crossover
between the values obtained in plain distilled water and those in saline gradually
occurred, the values in distilled water without calcium chloride becoming the lowest.
This is at variance with the results obtained in the presence of added AFIF or fibrinolysed
fibrinogen where the values in distilled water were always higher than the ones obtained
in saline both in the presence and in the absence of calcium chloride. Since the reversal
of coagulability of fibrinogen in physiological saline versus distilled water was
reproduced only when we mixed partially lysed human fibrinogen with completely lysed
human plasma, the conclusion was drawn that three prerequisites are necessary for
this phenomenon to occur: a) the fibrinogen must have been acted upon by fibrinolysin;
b) the fibrinogen must be of human origin; c) a substance produced by the action of
fibrinolysin on a plasmatic factor other than fibrinogen or, possibly, an intact plasmatic
factor, must be present.
