Plasminogen activity and antigen, tissue-type plasminogen activator (tPA) activity and antigen, plasminogen activator inhibitor (PAI) activity, and plasmin generation rates were determined in 32 normal newborn plasmas and 25 normal adult plasmas. The newborns showed reduced levels of plasminogen activity and antigen and tPA antigen, and activity, normal levels of PAI activity, and slower plasmin generation rates. The slower generation was shown to be due to the hypoplasminogenemia. The in vitro plasmin generation studies also showed that the newborn needed 11 times the usual concentration of urokinase and 5 times the usual concentration of tPA to achieve the minimal activation rate of the adult.
Current medical management programs for established joint diseases in hemophiliacs are unsatisfactory and do not modify the eventual outcome. D-penicillamine, a drug effective in the proliferative synovitis of rheumatoid arthritis, was evaluated in a rabbit model of hemarthroses-induced arthritis and in four hemophiliacs with chronic synovitis. The animals had intra-articular injections of citrate (left knees) and autologous citrated whole blood (right knees). Eight weeks later, the rabbits were divided into two groups: no treatment and D-penicillamine (50 mg/kg/day, IM) until sacrificed at 6 months. The saline-injected joints showed no inflammation and no iron deposition. The blood-injected knees showed iron deposition in both groups, the D-penicillamine animals had marked suppression of chronic inflammation. Of the four patients treated, three had clinical responses (reduction in synovial thickness, reduction in number of bleeds in the affected joint). One patient, who did not respond, developed mild-moderate proteinuria. Those patients who responded received between 5.3 and 7.1 mg/kg/day of the drug. Mild abnormalities in platelet aggregation were seen in the responders. This preliminary study suggests that D-penicillamine is beneficial in the chronic synovitis/arthritis induced by hemarthroses. Further trials are recommended.
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