Neutralization by protamine of the heparin activation of antithrombin III in plasma, in vitro, represents an equilibrium reaction in which by mass action heparin remains complexed only in the presence of an excess of protamine. Loss of this excess through enzymatic breakdown of the free protamine leads to instability of the complexes with liberation of the heparin, reestablishing antithrombin activity. This "heparin rebound" can also be produced by an increase in heparin levels or increased amounts of antithrombin III. These phenomena could occur after extracorporeal bypass procedures by an increase in heparin from whatever source or by added antithrombin III, through transfusions of fresh frozen plasma. A larger excess of protamine does not itself act as an anticoagulant but produces large heparin-protamine complexes that can still activate antithrombin III. Such large complexes, formed in vivo, could possibly block the pulmonary microcirculation and cause the acute pulmonary hypertension that has been reported after protamine infusions.
Sera from 16 of 23 (69.6%) patients with endometriosis, a potential autoimmune disease, and 2 of 17 (11.8%) control individuals had autoantibodies against the bovine carbonic anhydrase (CA) molecular weight marker, as determined by the Western blot technique. The reactivity of these antibodies to purified human CA I, human CA II, and two preparations of bovine CA II were investigated. Of the 16 endometriosis patients who were reactive to the bovine CA molecular weight marker, 14 were reactive to at least one purified human CA isoenzyme tested, 8 were reactive to at least one purified bovine CA II, and 2 did not react with any of the CA isoenzymes tested. Variation in cross-reactivity between species and in the biochemical characteristics of various CA isoenzyme preparations may partially explain these findings. Autoantibodies to CA isoenzymes have recently been reported in other autoimmune diseases. Further investigation is required to determine the significance of CA autoantibody production in patients with endometriosis.
A programme for the daily monitoring of Fresh Frozen Plasma (FFP) usage, combined with continuous education in the correct use of FFP, was started at William Beaumont Hospital in 1985. In 2 years, this had resulted in a 77% reduction in FFP usage. An analysis of the type of cases which received FFP, after the major reduction had occurred, from July, 1985 through June, 1989 is presented. During this time 2,612 units were administered to 873 patients, an average of 54 units per month. According to the accepted criteria established by the Hospital Transfusion Committee, 67% of the transfused units on the medical service were deemed indicated, compared with 54% on the surgical service. Most of the FFP was used to treat patients with liver disease, or receiving coumadin, or undergoing coronary bypass surgery. Conditions which will decrease the need for FFP administration are also presented for consideration. The results indicate that a consistent monitoring and education programme can keep blood and blood component usage at a defensible minimum.
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