Summary. The inhibitor‐neutralizing ability of plasma and Factor‐VIII concentrates from a group of 48 haemophilic patients and 30 normal persons has been studied. Factor‐VIII inhibitors were neutralized by the material from four of the haemophilic patients and all the normal subjects. The material from the larger group of 44 haemophilic patients showed no significant inhibitor‐neutralizing ability. The former group have been designated Haemophilia A+ because of the presence of material antigenically related to Factor VIII, and the latter group Haemophilia A− because of the lack of such material.
This study examines the effects of heat treatment for 72 h at 80 degrees C on the potential thrombogenicity of lyophilized human coagulation factor IX concentrates. Since heating generated minor amounts of thrombin, concentrate was prepared with antithrombin III addition prior to heat treatment. Changes in coagulation parameters were followed prior to and after infusion of 100 iu/kg of heated and unheated concentrates to dogs. All batches produced a transient fall in platelet count during infusion and a delayed rise in plasma fibrinopeptide A, accompanied by a minor prolongation of the activated partial thromboplastin time. Such changes were less marked for heated batches. Control infusion of a 'failed' factor IX concentrate showed an additional fall in fibrinogen, rise in fibrin degradation products and a more rapid rise in fibrinopeptide A, while thrombin infusion caused an even more dramatic intravascular coagulation. These studies indicated no increase in the potential thrombogenicity of freeze dried factor IX concentrates as a result of heat treatment.
Increased menstrual loss and irregular uterine bleeding are major drawbacks to acceptibility of intrauterine contraceptive devices (IUCDs). Fibrinolytic activity around IUCDs removed from 80 women was measured by embedding the device immediately after removal in a plasminogen-rich fibrin plate. In fifteen of the women an endometrial biopsy was also taken at the time of removal of the IUCD. In women who had the IUCDs removed because of bleeding a much higher fibrinolytic activity was found than in women not complaining of excessive bleeding. The fibrinolytic activity was shown to be due to plasminogen activator and not plasmin. The findings suggest that the excessive menstrual bleeding which occurs with the IUCD may be due to enhancement of fibrinolytic activity in the endometrium which can be modified by fibrinolytic inhibitors such as epsilon aminocaproic acid.
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