Abstract
Suitable quantities of trypsin will reduce to normal, in vitro, the prolonged clotting time of hemophilic blood. 1 The intravenous injection of trypsin into a hemophilic patient has never been attempted, chiefly because experiments on animals have shown that trypsin is toxic and causes intravascular coagulation. 2 , 3
However, the toxicity of trypsin is greatly reduced by injecting it slowly. Thus, crystalline trypsin∗ 4 dissolved in 200 to 300 ml of physiological saline was injected intravenously into 3 hemophilic patients and its effect on the coagulation time observed.
The coagulation time was measured at 37°C on duplicate samples of 2 ml of blood in chemically clean test tubes, 9 to 10 mm in diameter, previously rinsed with physiological saline. The end point is reached when the tube can be completely inverted without spilling the blood. 5
The results (Table I) show that a significant shortening of the coagulation time followed the injection of 300 mg of trypsin in 19 minutes and of 325 mg in 20 minutes respectively in 2 different hemophilic patients. The coagulation time returned to the initial value after one hour. Observation 11 (Table I) shows that no effect on the coagulation time followed the injection of 300 mg during a period of 120 minutes.
No toxic manifestations, local or general, were observed during or after the injections.
Table II shows that in vitro the optimal quantity of trypsin effective on the coagulation time of 2 ml of hemophilic blood was 0.25 mg. A significant effect was also observed with from 1.0 to 0.05 mg. Assuming the blood volume of the patients to be about 5000 ml, there seems to be a definite correlation between the effect of trypsin in vivo and in vitro. On this basis, a dose of 300 mg of trypsin should be expected to produce an effect in vivo.
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