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)

In this review, an attempt has been made to present new data on the mechanisms that can be involved in DVT and to emphasize the role of the cell in these processes. It has been demonstrated that cells can mediate the relevant expression of tissue factor without cell disruption and that the fibrinolytic responses can also be modulated by the cells. It has also been demonstrated that the fibrinolytic system seems to be designed to work on the cell surface based upon (1) the existence of specific receptors, (2) the modulation of the expression of these receptors and (3) the comprehensive increase in plasmin generation by up-regulating, for example, the plasminogen receptors. It could also be worthwhile to attempt to explain some beneficial effects of drugs such as heparins by studying their action on these compartments. It is important to note that recently Rosenfeld et al. have described an increase in t-PA and u-PA binding to endothelium by pre-incubation of endothelial cells with unfractionated heparin. This work would be a first step in a very exciting and interesting new era in the prevention of venous thromboembolism.
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PMID:Biochemical aspects of the pathogenesis of venous thrombosis. 228 80

Protein C and protein S serve as natural anticoagulants. Deficiencies of these proteins are often associated with recurrent deep vein thrombosis and coumarin induced skin necrosis. These two proteins function by selectively inactivating factors Va and VIIIa, two of the "cofactors" of blood coagulation. Hence, inhibition of coagulation by this pathway complements the better known inhibition mediated by the antithrombin III-heparin system. These observations suggest that protein C and/or activated protein C may prove useful in controlling thrombosis and/or DIC. We have developed a Ca2+ dependent monoclonal antibody which allows the rapid isolation of human protein C. This rapid isolation has allowed us to demonstrate that activated protein C can protect baboons from the lethal effects of E. coli/endotoxin and that protein C supplementation can minimize fibrinogen consumption following tissue factor infusion into dogs.
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PMID:Protein C, isolation and potential use in prevention of thrombosis. 330 68

The association of cancer with clinical abnormalities of blood coagulation, including superficial thrombophlebitis, deep vein thrombosis (DVT), and disseminated intravascular coagulation (DIC) is well-known, particularly in patients with solid tumors and acute promyelocytic leukemia (APL). Less commonly appreciated is the potential for the development of venous thromboembolic disease (TED) in patients with acute lymphocytic leukemia (ALL). Multiple mechanisms have been implicated for the activation of coagulation in these patients, with an emphasis on the contribution made by the procoagulant properties of the tumor cells themselves. We present two cases of patients with pre-B cell ALL, both of whom developed recurrent TED as the presenting manifestation of their leukemia and/or heralding relapse. The blast cells from one of the patients were studied for the presence of procoagulant activity (PCA) and by Northern blot analysis for tissue factor (TF) messenger RNA (mRNA). Neither PCA nor TF mRNA could be identified in highly purified populations of the lymphoblast cells. We conclude that recurrent TED can be a manifestation of ALL and that mechanisms other than the release of tumor cell procoagulants should be sought to explain the pathogenesis of thrombosis in some patients.
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PMID:Recurrent venous thrombosis as the presenting manifestation of acute lymphocytic leukemia: leukemic cell procoagulant activity is not responsible for the hypercoagulable state. 796 91

Cemented total hip replacement surgery is associated with intraoperative cardiorespiratory depression and postoperative proximal deep vein thrombosis which may be linked to an extreme intraoperative thrombin generation and local and systemic effects of monomethylmethacrylate (MMA) released into circulation from curing cement. This in vitro study demonstrates that MMA alone or in combination with thrombin have effects on monocytes and human umbilical vein endothelial cells (HUVEC) which modulate their procoagulant activities. Moderate doses of MMA had a slight tissue factor (TF) inducing effect on monocytes. Small doses of MMA (0.1-1 mg/ml) [corrected] markedly potentiated the TF inducing effect of thrombin or lipopolysaccharide (LPS) which was included as a reference stimulant. These TF modulating effects of MMA were not seen with HUVEC. However, the generation of fibrinopeptide A (FPA) in cell overlay plasma indicated enhanced procoagulant activity of HUVEC treated with moderate doses of MMA, probably reflecting MMA cytotoxicity leading to cell retraction and exposure of extracellular matrix. Furthermore, small doses of MMA had a slight enhancing effect on FPA generation when coincubated with thrombin. These findings indicate that MMA in concentrations found in central venous blood in vivo, alone or together with thrombin, directly or indirectly exert effects that contribute to activation of coagulation.
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PMID:Effect of monomethylmethacrylate on procoagulant activities of human monocytes and umbilical vein endothelial cells in vitro. 808 39

Dermatan sulfate is an antithrombotic glycosaminoglycan which has been shown to be effective in preventing deep venous thrombosis in general surgery patients when present at concentrations less than 1 microgram/ml. It has also been found to circulate physiologically in similar concentrations in pregnant women at term and in cord blood. We investigated the ability of dermatan sulfate added to plasma at 0.2, 0.5 and 1.0 microgram/ml to inhibit thrombin generation initiated by low concentrations of recombinant human tissue factor in defibrinated plasma. A dose dependent decrease in thrombin potential was demonstrated at therapeutically relevant concentrations of dermatan sulfate (0.5 and 1.0 microgram/ml) but there was no induction of a lag phase in thrombin generation. We were unable to demonstrate a significant effect on thrombin potential of dermatan sulfate at a concentration similar to that found in pregnancy plasma (0.2 microgram/ml). This indicates that either the dermatan sulfate concentration found in pregnancy plasma is not physiologically relevant or that our experimental system (which lacks platelets and fibrin) does not accurately reflect physiologic conditions. The effect on the thrombin potential was somewhat greater at the lowest concentration of tissue factor and amounted to a maximum inhibition of approximately 50% at 1 microgram/ml dermatan sulfate. A dose dependent increase in formation of thrombin-heparin cofactor II complexes and a decrease in thrombin-antithrombin complex formation with increasing dermatan sulfate concentration were observed at all dermatan sulfate concentrations. Prothrombin consumption was not changed by any dose of dermatan sulfate. We conclude that dermatan sulfate, at the concentrations tested, catalyses inhibition of free thrombin by heparin cofactor II but not efficiently enough to inhibit prothrombinase formation.
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PMID:The effects of dermatan sulfate at submicrogram/ml concentrations on in vitro thrombin generation. 872 17

Previous studies have reported that pre-operative plasmas of patients over the age of 40 years who developed post-operative deep vein thrombosis (DVT) had approximately twice the amount of proteolysed factor VII found in plasmas of patients in whom prophylaxis with heparin or low M(r) heparin was successful. These and other studies also reported higher concentrations of thrombin-antithrombin III in pre- and post-operative plasmas of patients who developed post-operative thrombosis than in plasmas of patients in whom prophylaxis was successful. Whether the extent of factor VII proteolysis seen in the patients who developed post-operative DVT is related to the severity of their disease or age is not known. This report investigated age-related changes in the concentrations of total factor VII protein, factor VII zymogen, factor VIIa, tissue factor pathway inhibitor, thrombin-antithrombin III, and prothrombin fragment 1 + 2 in normal plasmas and the relationships between these parameters. With the exception of thrombin-antithrombin III, statistically significant increases in the concentrations of these parameters with age were found. Additionally, the differences between the concentrations of total factor VII protein and factor VII zymogen, an index factor VII proteolysis in vivo, were statistically significant only for individuals over age 40. Using linear regression analysis, a significant correlation was found to exist between the concentrations of plasma factor VIIa and prothrombin fragment 1 + 2. Since factor VIIa-tissue factor probably initiates coagulation in vivo, we hypothesize that the elevated plasma factor VIIa (reflecting a less tightly regulated tissue factor activity and therefore increased thrombin production in vivo) accounts for the high risk for post-operative thrombosis seen in individuals over the age of 40.
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PMID:Age-related changes in factor VII proteolysis in vivo. 875 6

The area under the thrombin generation curve (the endogenous thrombin potential; ETP) has been proposed as a parameter for plasma-based hypercoagulability and to monitor anticoagulant treatment. We present an ETP assay for the routine laboratory using a centrifugal analyser. Throughput is 30 samples/h, within and between run imprecision is 4-5.6%. Suitable substrates were developed for the ranges of 10-500% and 2-100% of normal. Independent of tissue factor concentration (if > 4 pM), the normal value of the extrinsic ETP is 384.8 +/- 51.7 nM.min. The intrinsic ETP, triggered by ellagic acid, is 414 +/- 41 nM.min. The ETP is decreased to 15 and 35% of normal by oral anticoagulation (INR 2.5-4.0) and by heparin administration (APTT 1.5-2.5 x control). The ETP is increased in untreated subjects with congenital antithrombin deficiency and in women using oral contraceptives. In deep vein thrombosis (phlebographically confirmed), it is increased by 29.4% (extrinsic) and 53% (intrinsic). In (angiographically assessed) coronary artery disease the increase is by 10% and 17% respectively.
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PMID:The routine determination of the endogenous thrombin potential, first results in different forms of hyper- and hypocoagulability. 913 33

Heparin, a negatively charged sulphated glycosaminoglycan, is clinically the most important antithrombotic drug. Heparin augments the inhibitory activity of antithrombin (AT) towards thrombin, factor Xa (FXa) and other activated clotting enzymes. Tissue factor pathway inhibitor (TFPI) is an endogenous heparin releasable three domain Kunitz-type coagulation inhibitor which inhibits the crucial tissue factor-factor VIIa (TF-FVIIa) dependent coagulation pathway in the presence of FXa. The importance of the TF-FVIIa pathway and TFPI has recently been reviewed (1). TFPI is located to different vascular pools, the largest being the vascular endothelium from where TFPI can be released dose-dependently to the blood by heparins (2). TFPI is speculated to contribute to the anticoagulant properties of heparins, but to which degree is not yet fully understood. In recent years low molecular weight heparins (LMWH) have proven to be effective and safe both for prophylactic (3) and therapeutic treatment (4) of deep vein thrombosis (DVT). Protamine is the least toxic and clinically most commonly used antidote to heparin. However, in vitro and in vivo LMW heparinized blood is not fully neutralized by protamine, as substantial anti-Xa activity remains following neutralization (5). This post-protamine effect has been shown to be partly TFPI dependent when measured in a dilute TF-dependent assay (6,7). We undertook this in vivo study on healthy volunteers in order to investigate whether TFPI released by UH or LMWH (intravenous (iv) or subcutaneous (sc)) remains in the circulation following neutralization of the heparin activity with protamine sulphate (PS). We measured TFPI by three different methods-chromogenic activity, anticlotting activity and a new antigen assay specific for full-length and three-domain TFPI.
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PMID:The effect of protamine sulphate on plasma tissue factor pathway inhibitor released by intravenous and subcutaneous unfractionated and low molecular weight heparin in man. 918 23

Venous valves are more frequent in distal veins and venulae, providing a protecting action against blood skin reflux. Structurally simple, collagen and endothelium, they allow a cavity to be formed by distension, when occlusion occurs. Venous angioscopy can distinguish bicuspid floating valves, reinforced, reinforcing valves with free edges and seat valves as well as the presence of apertures of small collateral vessels in the sinus, of which they play a role in the filling up. Valves are inefficient in supine and in standing among 20% of the adult population. Sinuses allow vortices to be created, low recirculating zones, where blood flow move slowly in niches, at a low shear rate, independently from the main stream. A deep vortex is located in sinus, usually empty, but likely to receive red cell aggregates and leukocytes in the condition of stasis and hyperviscosity. Such a vortex is hypoxic, cause of endothelial activation. In such areas fibrin-leucocytic nidus are created, histologically recognized, of which sub-endothelium has become thick and thrombogenic. Two stages characterized its progression: stage I: a few alteration in the valves, little thrombin generation, taken over by the coagulation inhibitors: AT III, APC and TFPI. Stage II: damaged valves, local consumption of the inhibitors and extended generation of thrombin over the platelets, through factor IXa. Hereditary inhibitor deficits increase the risk (frequent factor Leyden V). When the coagulation cascade is considered, VIIa-tissue factor complex appears to be the thrombotic pathway, leading first to wall linked thrombin, uneasily reached by AT III and facteur IXa non inhibited by TFPI, therefore explaining the platelet extension. Monocytes, which can bear tissue factor, may be "lodged" inside the niches. Besides this important role in deep venous thrombosis, incompetent venous valves are responsible for the skin venous hypertension, a subsequent ground for ulcers. Their role in chronic venous insufficiency is uncertain. In the near future, venous angioscopy will bring about new findings about the pathophysiology of venous valves.
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PMID:[Venous valves in the legs: hemodynamic and biological problems and relationship to physiopathology]. 948 Mar 31

Deep venous thrombosis is initiated primarily in the pockets of the valves of the veins of the lower limbs and the main pelvic veins. In addition to a genetic predisposition there are several acquired conditions associated with deep venous thrombosis such as major surgery, trauma, cancer, pregnancy, and immobilization. While major diseases as well as hormonal changes have been shown to cause changes in blood coagulation and fibrinolytic factors, the impact of immobilization per se is much less clear. It has been shown that in the absence of intermittent pulsatile flow the blood within the valve pockets became rapidly hypoxic when undisturbed during streamline flow (i.e. when "static"). Hypoxia on the other hand has been shown to cause procoagulatory changes of the vascular endothelium (e.g. production of platelet activating factor [PAF], expression of tissue factor), adhesion and activation of leukocytes and expression of tissue factor on their surface, as well as the activation of platelets. Together with reduced removal and/or inactivation of active clotting factors these mechanisms might contribute to the development of deep venous thrombosis during immobilization.
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PMID:[Pathophysiology of immobilization]. 1037 18


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