Hematin: unique effects of hemostasis
| Autor: | David Green, Robert Glueck, Chung-hsin Ts'ao, Isaac Cohen |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Adult
Male Platelet Aggregation Immunology Heme Pharmacology In Vitro Techniques Biochemistry Fibrin Porphyrias Thrombin polycyclic compounds medicine Humans Platelet Blood coagulation test Disseminated intravascular coagulation medicine.diagnostic_test biology Aspirin Chemistry Heparin Reptilase time Fibrinogen Cell Biology Hematology Blood Coagulation Disorders medicine.disease Glucose Coagulation biology.protein Hemin Blood Coagulation Tests medicine.drug Partial thromboplastin time |
| Zdroj: | Blood. 61(2) |
| ISSN: | 0006-4971 |
| Popis: | Hematin is clinically useful in the treatment of acute intermittent porphyria. Recently, hematin-induced coagulopathy has been reported, and a patient we treated bled during hematin therapy. On 3 separate occasions, infusions of hematin (4 mg/kg) induced thrombocytopenia, prolongation of the prothrombin time, partial thromboplastin time. Reptilase time, and apparent decreases in fibrinogen and increases in fibrin(ogen) degradation products (FDP). However, fibrinogen assayed by heat precipitation was unchanged, the protamine paracoagulation test was negative, there was no red blood cell fragmentation, and plasminogen and antithrombin III remained normal, excluding the presence of disseminated intravascular coagulation. Furthermore, premedication with heparin, 5000 U i.v., failed to prevent the lengthening of the Reptilase time and exacerbated the thrombocytopenia. In vitro studies revealed that hematin, 0.1 mg/ml, aggregated platelets and induced the release of 14C-serotonin and adenosine triphosphate (ATP). Hematin also aggregated washed or gel-filtered platelets but had no effect on formalin-fixed platelets. Aggregation was inhibited by aspirin (0.12 mg/ml), adenosine triphosphate, and apyrase, suggesting that hematin aggregated platelets by inducing adenosine diphosphate (ADP) release. Hematin (0.07 mg/ml) progressively inactivated thrombin and 0.1 mg/ml prolonged the Reptilase time. Thus, hematin is unique in that it both induces platelet aggregation and inhibits coagulation. |
| Databáze: | OpenAIRE |
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