The precise quantitation of activated factors in human factor IX concentrates has been accomplished with the use of recently developed, specific assays for factors IXa, Xa, and thrombin. The assay for factor IXa, which measures the initial rate of 3H-factor-X activation, was shown to be specific for factor IXa in the concentrates. Activated factor IX concentrates contained 1.0-2.3 microgram/ml ...

Six patients received platelet concentrate transfusions from their HLA-identical siblings. Platelet concentrates were administered either fresh, or after being frozen in 10% dimethylsulfoxide, at a slow controlled rate (1 degree C/min) or rapidly (approximately 8 degrees C/min) in the vapor-phase of a liquid nitrogen refrigerator. The median freeze-thaw loss was 13.5%. The mean 1-hr and 20-hr c...

The incidence and characteristics of HLA alloimmunization following transfusions of leukocyte concentrates as a source of enzyme replacement were determined in male patients with Hunter's syndrome. Five patients were given leukocyte concentrates from HLA matched donors (Group I) and another five patients received leukocyte concentrates from non-HLA matched donors (Group II). No other blood prod...

Liver disease and thromboembolism are the most frequent and severe side effects associated with the use of clotting-factor concentrates in haemophiliacs. Knowledge and careful evaluation of the risk factors related to their development appear to be the most reasonable policy for prevention. themolysis due to significant isoantibody infusion and bleeding associated to abnormal platelet function ...

The polymerase chain reaction (PCR) was used to detect hepatitis C (HCV) viral sequences (HCV-RNA) in clotting factor concentrates that had been stored at 4 degrees C for 1 to 16 years. A total of 43 concentrates were tested, comprising 31 batches of factor VIII, 6 of factor IX, 2 of antithrombin III, 3 of FEIBA, and 1 of factor VII. HCV-RNA was detected in 13 of the 43 batches (30.2%). Concent...

Factor IX concentrates were evaluated for their factor VII content and for the presence of activated factor VII through use of a coupled amidolytic assay insensitive to activated factor VII and a clotting assay sensitive to activated factor VII. The factor VII content of the concentrates studied (except for one concentrate purposely produced to exclude factor VII) varied between 33 and 621 U/vi...