Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0149871 (deep vein thrombosis)
 12,364 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Defibrotide, a deoxypolyribonuclide, has been found to modulate endothelial cell function causing increase in t-PA and decrease in PAI levels and also increase in PGI2 production. In addition, it increases platelet c-AMP levels and decreases MDA and TXB2 formation in human. Defibrotide inhibits platelet aggregate formation in vitro experiments as well as end-to-end anostomosis in rats. So, defibrotide inhibits the activation of platelets. Besides an increase of protein C and S levels a synergic action of heparin was observed in animal experiments. A strong antithrombotic effect has been observed in animal models. The drug has a beneficial effect in the cases of DVT, POVD, stroke and thromboembolism. Through its action we may say that the drug acts in a novel fashion in contrast to the other drugs used in this area. Defibrotide is a single-stranded polydeoxyribonucleotide obtained from deoxyribonucleic acid of mammalian lungs by controlled depolimerization. Since 1981 in our laboratory and in the clinical department we have been investigating a newly developed agent defibrotide in vitro experiments, animal experiments, and also its clinical pharmacology and clinical application. Some of our findings are already published and compared with literature (40, 43, 46). Because of the limited space we are not going to review the literature in detail but we are going to summarize our observations on this compound in the following order. I--in vitro experiments, II--Animal experiments, III--clinical pharmacology in human.
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PMID:The pharmacology and clinical pharmacology of defibrotide: a new profibrinolytic, antithrombotic and anti-platelet substance. 210 24

Increased urinary metabolites of the antiaggregatory vasodilator prostacyclin (PGI2) and the proaggregatory vasoconstrictor thromboxane A2 (TXA2) have been reported in deep vein thrombosis; however, the tissue(s) of origin is uncertain. Because little is known about the formation of PGI2 or TXA2 from its common precursor, prostaglandin (PG) endoperoxide H2 (PGH2), by varicose veins, we determined the formation of 6-keto-PGF1 alpha (the stable metabolite of PGI2), TXB2 (the stable metabolite of TXA2), and PGE2. Segments of normal saphenous vein and varicose vein (nine and six patients, respectively) were incubated with 10 microM [14C]PGH2 for 2 min at 37 degrees C; products were separated by thin-layer chromatography. Surface area and mass of normal and varicose vascular segments were 19.5 +/- 0.8 versus 18.8 +/- 0.6 mm2 and 11.6 +/- 1.4 versus 10.7 +/- 0.7 mg, respectively. Formation of 6-keto-PGF1 alpha and TXB2 by the segments of varicose vein was significantly increased over that of normal vein: 157 +/- 14 versus 243 +/- 17 pmole of 6-keto-PGF1 alpha (P less than 0.005) and 22 +/- 3 versus 35 +/- 5 pmole of TXB2 (P less than 0.01). The formation of PGE2 by segments of varicose vein was not significantly different from that of normal vein (201 +/- 9 vs 219 +/- 11, respectively). Deoxyribonucleic acid (DNA) content of normal and varicose vein was 1.69 +/- 0.12 and 1.51 +/- 0.13 mg per gram of tissue, respectively. The data suggest that the increased PGI2 formation may reflect increased activity or content of PGI2 synthase. The increase in TXA2 formation may reflect increased productivity or an increased presence of residual platelets or microemboli.
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PMID:Increased prostacyclin and thromboxane A2 formation in human varicose veins. 211 84

The effect of a single dose of 500 mg acetaminophen (paracetamol) on the in vivo synthesis of prostacyclin was studied in healthy volunteers by measurements of the urinary excretion of 2,3-dinor-6-keto-PGF1 alpha. Acetaminophen caused a marked reduction of prostacyclin synthesis for 6-8 hours without any obvious effect on the thromboxane synthesis. Thus, acetaminophen may at least theoretically be disadvantageous for patients suffering from diseases where prostacyclin mediated vascular defence mechanisms are activated, like myocardial infarction, deep vein thrombosis and following surgery.
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PMID:Pronounced reduction of in vivo prostacyclin synthesis in humans by acetaminophen (paracetamol). 266 1

Our studies on the urinary excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha in humans strongly indicate that these metabolites are good indicators of the in vivo synthesis of TxA2 and PGI2. Our finding that physical exercise increases PGI2 synthesis was of particular importance for the design of adequate studies on the effects of various drugs on the in vivo formation of PGI2. The rapid recovery (within 3-4 h) of PGI2 formation found following administration of 1.0 g of aspirin together with the long-lasting inhibition of TxA2, suggests that in the prophylaxis of thromboembolic events an intermittent dosage of 0.5 g of aspirin every third day should be a better alternative than daily low or high doses of aspirin. The increased TxA2 formation found in patients with acute myocardial infarction, deep vein thrombosis and in patients following insertion of synthetic surfaces into the circulation, is very likely a reflection of an increased activation of platelets. The increased TxA2 synthesis may cause further platelet activation, vasoconstriction and activation of the coagulation system. Thus, theoretically, inhibition of TxA2 could diminish platelet activation and reduce the risk of thrombotic complications. It is well known that the interaction between platelets and the vessel wall plays an important role in haemostasis and in the development of thrombosis. On the basis of its biological properties, PGI2 may play a local haemostatic role in the regulation of this interaction. Our studies of myocardial infarction and deep vein thrombosis clearly demonstrate the involvement of PGI2 in those diseases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Measurements of the in vivo synthesis of thromboxane and prostacyclin in humans. 306 Sep 85

The urinary excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha (the major urinary metabolites of thromboxane B2 and prostacyclin) was measured in ten patients with confirmed deep vein thrombosis, using specific methods based on gas chromatography - mass spectrometry with deuterium-labelled internal standards. Measurements of these major urinary metabolites makes it possible to monitor the in vivo formation of thromboxane A2 and prostacyclin. The results demonstrate an abnormally high and very variable excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha in patients with deep vein thrombosis. This indicate that both thromboxane A2 and prostacyclin are involved in the course of events associated with this disease.
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PMID:Thromboxane and prostacyclin formation in patients with deep vein thrombosis. 355 98

Defibrotide is a deoxyribonucleic acid derivative extracted from mammalian organs, which has been developed for the treatment of a number of vascular disorders. It appears to increase fibrinolysis and may possess antithrombotic, antiatherosclerotic and anti-ischaemic actions, probably due to its ability to selectively increase prostaglandin I2 and E2 levels and to increase tissue plasminogen activator and decrease plasminogen activator inhibitor function. Defibrotide is available as an intravenous and intramuscular preparation, and also as an oral formulation for long term use. Trials performed to date have provided initial evidence that defibrotide is effective in the treatment of peripheral obliterative arterial disease and acute thrombophlebitis, while preliminary data suggest possible use in preventing fibrin deposition in the circuitry of renal haemodialysis equipment. Efficacy in preventing deep vein thrombosis after surgery has been demonstrated but defibrotide does not appear to offer any therapeutic advantage over heparin. Further clinical experience is required in other disorders, including acute myocardial infarction, Raynaud's phenomenon, renal thrombotic microangiopathy and renal transplant rejection, before adequate assessment of efficacy in these areas can be made. Defibrotide is well tolerated, as assessed in trials of up to 6 months duration, with a low global incidence of adverse events (< 1 to 9%). Mild allergic reactions and gastrointestinal disturbances have occasionally been described, and a hypotensive effect has also infrequently been observed. Thus, available data suggest that defibrotide is a well tolerated agent with little or no anticoagulant activity, which is conveniently available in both parenteral and oral formulations. Initial data indicate that the drug may be a useful alternative in the treatment of peripheral obliterative arterial disease and thrombophlebitis, while its therapeutic potential in other vascular disorders and efficacy relative to established agents remains to be fully determined.
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PMID:Defibrotide. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in vascular disorders. 768 75

Defibrotide, a polydeoxyribonucleotide, has been found to modulate endothelial cell function, causing an increase in tissue plasminogen activator (t-PA) levels, a decrease in plasminogen activator inhibitor (PAI) levels, and an increase in prostaglandin I2 (PGI2) formation in humans. Defibrotide has no direct anticoagulant effect but has a synergistic action with heparin. A strong antithrombotic effect has been observed in animal models. Thus, defibrotide has a beneficial effect in cases of deep venous thrombosis (DVT), peripheral obliterative vascular disorder (POVD), stroke, vasculitis, and thromboembolism. Defibrotide also inhibits platelet function and activation. A significant decrease in platelet aggregate formation on the suture line in microarterial anastomosis in rats is one way defibrotide can inhibit platelet function and activation. In humans, a slight prolongation' of the lag period in collagen-induced aggregation has been observed. In addition, a slight decrease in the maximum amplitude of the secondary wave of ADP and adrenalin-induced aggregations was also found. Platelet adhesion is diminished, the platelet differential count on formvar membrane is altered, and platelet aggregate formation is significantly inhibited. With an increase in platelet cyclic AMP (cAMP) content and a decrease in malonyl dialdehyde (MDA) and thromboxane B2 (TXB2) formation, the levels of platelet secretion products such as PF-4 and beta-thromboglobulin (beta-TG) in plasma decreased progressively. It was also demonstrated that the 14C-glucose transport defect of the platelet membrane of atherosclerotic patients was partially corrected with defibrotide treatment.
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PMID:Effect of defibrotide on platelet function. 880 24

Primary pulmonary hypertension (PPH) is a condition characterized by sustained elevation of pulmonary artery pressure (PAP) without demonstrable cause. The most common symptom at presentation is dyspnea. Other complaints include fatigue, chest pain, syncope, leg edema, and palpitations. Right heart catheterization is diagnostic, showing a mean PAP >25 mmHg at rest and >30 mmHg during exercise, with a normal pulmonary capillary wedge pressure. In the National Institutes of Health-PPH registry, the median survival period was 2.8 years. Treatment is aimed at lowering PAP, increasing cardiac output, and decreasing in situ thrombosis. Vasodilators have been used with some success in the treatment of PPH. They include prostacyclin, calcium-channel blockers, nitric oxide and adenosine. Anticoagulation has also been advised for the prevention of deep vein thrombosis, pulmonary embolism, and in situ thromboses of the lungs. New drug treatments under investigation include L-arginine, plasma endothelin-I, and bosentan. Use of oxygen, digoxin, and diuretics for symptomatic relief have also been recommended. Patients with severe PPH refractory to medical management should be considered for surgery.
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PMID:Primary pulmonary hypertension. 1172 93

HEPARIN-INDUCED THROMBOCYTOPENIA (HIT): Management of heparin-induced thrombocytopenia (HIT) and treatment options have significantly changed recently. Heparin may induce two types of thrombocytopenia. Type I, occurring earlier with a much higher rate of incidence (5-30%), is characterized by mild thrombocytopenia without significant clinical manifestations. Type II, is less frequent (0.5-2%), life threatening immune type, develops following a period of minimum 5-7 days upon introduction of heparin therapy (patients earlier treated with heparin are excluded). Type II heparin-induced thrombocytopenia with severely reduced platelet count may be clinically manifested by thrombosis in 20-50% cases within the period of 30 days. HIT is suspected in persons resistant to heparin with relatively reduced platelet count, though HIT is described in person with normal platelet counts, as well. None of available assays used for HIT detection is completely reliable. Sensitivity of a highly specific platelet aggregation assay is only 36%, sensitivity and specificity of 14C-serotonin release assays amounts to 95%, while ELISA using a heparin/platelet factor-4 target has a sensitivity of 85%. Thus, it is sometimes necessary to combine functional and antigen assays. Furthermore, new classes of antigen assays, like antibody detection tests of complexes between heparin and neutrophil-activating peptide-2 as well as those between heparin and interleukin-8, have been used. CURRENT THERAPY OPTIONS: Current therapy options exclude formerly applied low-molecular-weight heparins due to the existing cross-reactivity of 80-100%. Danaparoid sodium exhibits in vitro cross-reactivity of 10-61%, clinically manifested in less than 5% of patients. Two drugs are drugs of choice in HIT type II treatment: lepirudin, especially in patients without renal failure, and argatroban, particularly in patients with renal failure. The following procedures and agents are also efficient: asmapheresis in the first four days, high-dose intravenous gammaglobulin, antiaggregans, especially ADP antagonists, aspirin, dipirydamole, dextran, prostacyclin analagoues, thrombolytic therapy as well as thromboembolectomy. Oral anticoagulants are not administered in active HIT type II, in deep vein thrombosis with high international normalized ratio (INR) and thrombin-antithrombin complexes, and low protein C levels to avoid the possibility of venous limb gangrene development. They can be administered in a stable phase, when the thrombin generation is controlled by previous administration of one of the above-mentioned alternative anticoagulants.
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PMID:[Heparin-induced type II thrombocytopenia--new views on diagnosis and therapy]. 1456 48

Blood dose not normally coagulate in the blood vessels covered with endothelial cells, because these cells contain some substances responsible for antithrombotic action such as thrombomodulin, heparin-like substance, prostacyclin, nitric oxide and tissue plasminogen activator. Most important role of blood coagulation is hemostasis. Blood can coagulate in two ways: intrinsic coagulation pathway and extrinsic coagulation pathway that is activated by negatively charged substances and FVIIa-tissue-factor (TF) complex, respectively. Prothrombin time(PT) can represent extrinsic pathway, while activated partial thromboplastin time (APTT) can represent intrinsic pathway. PT is prolonged in such diseases as vitamin K deficiency, hepatic failure and warfarin intake, while APTT is prolonged such diseases as hemophilia A & B, von Willebrand disease and lupus anticoagulant. Cross mixing test is very useful to assess prolonged clotting time. FDP means fibrin/fibrinogen degradation products and D-dimer is the smallest products of fibrin degradation. These markers are often used to diagnose disseminated intravascular coagulation (DIC) and deep vein thrombosis (DVT). Thrombin-antithrombin complex (TAT) and plasmin-alpha2 plasmin inhibitor (PIC) can be used to evaluate the extent of coagulation and fibrinolysis activation, respectively. These two markers is essential for classify the pathophysiology of DIC: DIC with suppressed fibrinolysis, enhanced fibrinolysis or balanced fibrinolysis. In conclusion, exact interpretation of hemostatic and fibrinolytic markers is one of the most important abilities in clinical situation.
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PMID:[Interpretation of hemostatic and fibrinolytic markers]. 2218 80


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