Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0012739 (disseminated intravascular coagulation)
 8,673 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The naturally occurring anticoagulant from medicinal leeches, hirudin, which we isolated and biochemically analyzed 30 years ago as a miniprotein with specific antithrombin activity, has afterwards been employed for scientific and diagnostic purposes in hematology. Pure hirudin proved to be an antithrombotic agent of high quality that displays an antithrombotic action dependent upon its blood level. After intravenous injection, it is distributed in the extracellular space and is almost completely eliminated through the kidneys by glomerular filtration in a biologically active form. The efficacy of hirudin in preventing venous and arterial thrombosis and disseminated intravascular coagulation was demonstrated in various animal models. Clinical pharmacological studies corroborated the specific pharmacodynamic and pharmacokinetic properties of hirudin found in animal experiments. Genetic engineering led to the availability of sufficient quantities of recombinant hirudin (r-hirudin) for clinical purposes. Pharmacologic profiling of r-hirudin showed that both its pharmacokinetic and pharmacodynamic characteristics are very similar to those of native hirudin. Clinical pharmacological studies with r-hirudin revealed that, at single therapeutically relevant doses, r-hirudin is a well-tolerated and potent anticoagulant without any detectable side effects and allergic reactions. Further preclinical studies of r-hirudin should concentrate on identifying possible indications for use, on the development of r-hirudin preparations and derivatives, and on the development of antidotes for hirudin.
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PMID:Past, present and future of hirudin. 189 86

Antithrombotic potency of recombinant hirudins rHV2, rHV2-Lys47 and rHV2-Arg47 was studied in a model of experimental thrombosis induced by tissue factor in the rat. Venous thrombosis was induced by i.v. injection of 25 mg/kg tissue factor followed by stasis of the inferior vena cava. In this model natural recombinant hirudins, rHV2 and rHV2-Lys47 injected 5 min before thrombo-plastin totally inhibited thrombosis in the same micrograms range as heparin or natural hirudin extracted from leeches. However, the mutant variant rHV2-Arg47 gave a maximal 60% inhibition of thrombosis. Variants rHV2-Lys47 (30 micrograms/kg) and rHV2-Arg47 (157 micrograms/kg) injected 5 min before thromboplastin prevented by 90 to 100% the drop in platelet count observed during the disseminated intravascular coagulation induced by thromboplastin injection. Recombinant hirudins were less anticoagulant than heparin as measured by an APTT on rat plasma. After rat tail transection, rHV2-Lys47 caused a 2-fold smaller prolongation of the bleeding time than an equivalent antithrombotic dose of heparin. Plasmatic elimination of rHV2-Lys47 from rat plasma after i.v. injection had a fast distribution phase with a half-life of 3 min during which 90% of injected rHV2-Lys47 was lost and was followed by a slower elimination phase. Thus recombinant hirudin rHV2-Lys47 appears as a promising potent antithrombotic agent for the prevention of thrombin-dependent venous thrombosis and disseminated intravascular coagulation.
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PMID:Inhibition by recombinant hirudins of experimental venous thrombosis and disseminated intravascular coagulation induced by tissue factor in rats. 236 20

Thrombin plays a key role in thrombosis and haemostasis, and is selectively inhibited by hirudin and synthetic inhibitors. Hirudin, a polypeptide (molecular weight 7,000 daltons) extracted from medicinal leeches, can now be produced by gene technology. Hirudin binds selectively to thrombin with high affinity and inhibits its enzymatic properties. Besides heparin, hirudin is not inhibited by platelet factor 4; it prolongs in vitro and ex vivo routine blood coagulation assays and prevents thrombosis in a number of animal models without increasing haemorrhagic risk. In humans, hirudin disappears from the blood with a half-life of 1 h, is devoid of undesirable side effects and has been shown to be efficient in the treatment of chronic disseminated intravascular coagulation (DIC). A number of synthetic direct thrombin inhibitors have been described, including benzamidine derivatives which share identical pharmacological properties with hirudin; however their biological half-life after i.v. injection is shorter. Other derivatives (amidino-phenyl-pyruvic acid) have longer half-lives and have been used to treat chronic DIC in man.
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PMID:Pharmacology of selective thrombin inhibitors. 304 69