American journal of hematology
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Randomized Controlled Trial Clinical Trial
Effect of tranexamic acid on platelet ADP during extracorporeal circulation.
Seventeen adults received the antifibrinolytic drug tranexamic acid during cardiac surgery utilizing extracorporeal circulation (ECC). In 8 patients, drug administration began prior to skin incision (pre-ECC); infusions commenced after ECC and protamine administration in another 9 patients (post-ECC). Compared with the post-ECC group, the pre-ECC group exhibited less bleeding via mediastinal drains (420 vs. 655 mL/12 h median, P = 0.024), decreased frequency of the presence (greater than or equal to 10 micrograms/mL) of fibrin split products (P less than 0.05), and greater platelet dense granule content of adenosine diphosphate after surgery (15.47 vs. 4.05 nmoles/mg protein median, P = 0.021). ⋯ Plasmin inactivated with tranexamic acid retained its ability to inhibit thrombin-induced platelet activation, thus suggesting that tranexamic acid inhibits plasmin's catalytic activity and not its binding to platelets. Both clot lysis and platelet dysfunction may contribute to bleeding after ECC. Tranexamic acid blocks plasmin-induced partial platelet activation during ECC, thus preserving platelet function and promoting hemostasis after ECC.
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Case Reports
Recombinant human erythropoietin for a Jehovah's Witness with anemia of thermal injury.
We report the use of recombinant human erythropoietin (rh-Ep) as an alternative to transfusion therapy in a burn victim who was a Jehovah's Witness and refused blood transfusion. Despite endogenous elevated erythropoietin levels, the patient was reticulocytopenic and administration of rh-Ep was accompanied by a 10-fold increase in reticulocyte response and a rise in hemoglobin from 7.4 to 10.4 g/dl over a 12-day period. We suggest that the exogenously administered erythropoietin overcame a clinically inadequate endogenous erythropoietin response.
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A case of arsenic intoxication presenting as a myelodysplastic syndrome is reported. A 41-year-old woman with a 6-month history of gastrointestinal and neurological symptoms was noted to be pancytopenic at presentation. ⋯ Treatment with British anti-Lewisite (BAL) resulted in the resolution of gastrointestinal symptoms and hematological abnormalities although the neurological complications progressed. This case emphasizes that heavy metal intoxication should be considered in the differential diagnosis of any individual presenting with the hematological features of myelodysplasia especially when accompanied by clinical features considered atypical for primary or secondary myelodysplasia.
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Desmopressin acetate (DDAVP) is known to stimulate the release of tissue-type plasminogen activator (t-PA) from endothelial cells, but it is unclear whether the increased t-PA actually elicits the plasmin generation and fibrin(ogen)olysis in the circulating blood. We measured plasma levels of plasmin-alpha 2-plasmin inhibitor complex, fibrinogen degradation products (FgDP) and fibrin degradation products (FbDP) following desmopressin infusion in 19 patients with bleeding disorders or thrombophilia. Administration of desmopressin (0.3-0.4 microgram/kg) produced a 4.0-fold increase in plasmin-alpha 2-plasmin inhibitor complex at 30 min, whereas neither FgDP nor FbDP was elevated significantly. These findings indicate that desmopressin infusion provokes the generation of plasmin in vivo, but most of the plasmin generated is complexed to alpha 2-plasmin inhibitor and does not degradate fibrin or fibrinogen.