Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemorrhagic diathesis was observed in patients with renal insufficiency after carbenicillin at serum levels greater than 300 mug/ml. Normal coagulation factors (F. I, II, V, VII, VIII, X), normal PTT, normal platelet counts, negative ethanol gelation test (fibrin monomers) were found as well as a prolongation of thromboplastin time (Quick), thrombin time, reptilase time and thrombin coagulase time. Platelet function was disturbed. In addition, the plasmatic system was involved: inhibition of fibrinogen-fibrin conversion (Belitser assay) and enhanced antithrombin III activity; in vivo the latter was ascribed to a heparin-like activity. In vitro, abnormal III was seen: however an enhanced antithrombin III activity in vitro was not found with carbenicillin and various penicillin derivatives. This study demonstrates that carbenicillin, in addition to its known effect on platelet function, also disturbs the plasmatic coagulation system. This additional effect of carbenicillin is clinically important since protamin chloride effectively blocks bleeding without interfering with antibacterial activity. Both penicillin and penicillin derivatives have been shown to interfere with hemostasis and to cause clinically manifest hemorrhagic diathesis (Fleming and Fish 1947, Lurie et al. 1970a, b, McClure et al. 1970, Yudis et al. 1972, Demos 1971, Waisbren et al. 1971). Carbenicillin interferes with ADP-, collagen- or thrombin-induced platelet aggregation and with the release reaction both in vivo (McClure et al. 1970, Cazenae et al. 1973) and in vitro (McClure et al. 1970, Cazenave et al. 1973). In addition Lurie and colleagues (1970b) concluded that an inhibition of the conversion of fibrinogen to fibrin is involved although no experimental details were given. Later Brown and colleagues (1974) concluded that carbenicillin at usual dose levels "only affects the platelet component of hemostasis and has little effect on fibrin formation or other phases of coagulation in patients with normal renal function".
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PMID:Bleeding in uremic patients after carbenicillin. 103

Heparin cofactor II (HC) is a plasma serine proteinase inhibitor (serpin) that inhibits the coagulant proteinase alpha-thrombin. We have recently demonstrated that proteolysis of HC by catalytic amounts of polymorphonuclear leukocyte proteinases (elastase or cathepsin G) generates leukocyte chemotaxins (Hoffman, M., Pratt, C. W., Brown, R. L., and Church, F. C. (1989) Blood 73, 1682-1685). One of four peptides produced when HC is degraded by neutrophil elastase has chemotactic activity for both monocytes and neutrophils with maximal migration comparable to formyl-Met-Leu-Phe, the "gold standard" bacterially derived chemotaxin. The amino-terminal sequence of this HC peptide is Asp-Phe-His-Lys-Glu-Asn-Thr-Val-... and the peptide corresponds to Asp-39 to Ile-66 of HC. A variety of synthetic peptides derived from this sequence were evaluated for leukocyte migration activity, and a dodecapeptide from Asp-49 to Tyr-60 (Asp-Trp-Ile-Pro-Glu-Gly-Glu-Glu-Asp-Asp-Asp-Tyr) was identified as the active site for leukocyte chemotactic action. The 12-mer synthetic peptide possesses significant neutrophil chemotactic action at 1 nM (60% of the maximal activity of formyl-Met-Leu-Phe), while a peptide with the reverse sequence has essentially no chemotactic activity. Cross-desensitization experiments also show that pretreatment of neutrophils with a 19-mer peptide (Asn-48 to Ile-66) greatly reduces subsequent chemotaxis to HC-neutrophil elastase proteolysis reaction products. When injected intraperitoneally in mice, the HC-neutrophil elastase digest elicits neutrophil migration. Our results demonstrate that not only does HC function as a thrombin inhibitor, but that limited proteolysis of HC near the amino terminus yields biologically active peptide(s) which might participate in inflammation and in wound healing and tissue repair processes.
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PMID:Leukocyte chemoattractant peptides from the serpin heparin cofactor II. 198 58

This study investigated the reaction of heparin cofactor II (HCII) with stimulated polymorphonuclear leukocytes (PMN). We have expanded upon previous studies showing that HCII can be degraded by stimulated PMN (Sie, P., Dupouy, D., Dol, F., and Boneu, B., Thromb. Res. 47, 657-664, 1987), and that chemotactic activity is produced when HCII is partially proteolyzed with purified leukocyte elastase or cathepsin G (Hoffman, M., Pratt, C.W., Brown, R.L., and Church, F.C., Blood, 73, 1682-1695, 1989). We found that HCII was proteolyzed by stimulated PMN, generating peptides with chemotactic activity. Both proteolysis and generation of chemotactic activity were inhibited by a specific leukocyte elastase inhibitor and by more general proteinase inhibitors. Leukocyte elastase activity was lost upon addition of either inhibitor. Heparin and dermatan sulfate altered the pattern of proteolysis. Our results suggest that HCII may be involved not only in functions related to thrombin inhibition but also in regulating acute inflammation.
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PMID:Production of chemotactic peptides by neutrophil degradation of heparin cofactor II. 230 Sep 26

Mercuric chloride (HgCl2) induces in Brown Norway (BN) rats an autoimmune disease characterized by a biphasic glomerulonephritis (GN). A transient nephrotic syndrome occurs during the third and fourth weeks after the first HgCl2 injection. Related to nephrotic syndrome, an hypercoagulable state develops with decreased factor XII and anti-thrombin III (AT III) levels and increased factor V activity and fibrinogen concentration. Moreover, during the same period, most of the rats were found thrombocytopenic. The presence of soluble fibrin monomer complexes and of fibrin degradation products (FDP) in the plasma of these rats associated with fibrin thrombi in glomerular capillary lumen proved the occurrence of disseminated intravascular coagulation (DIC). DIC was responsible for the death of several rats but most of these survived and clotting abnormalities were no longer found. Numerous factors can explain the occurrence of DIC in this model: anti glomerular basement membrane antibodies, circulating immune complexes, complement activation and/or glomerular endothelial cell detachment. The HgCl2 induced autoimmune disease appears as a good experimental model to study the relation between coagulation process and glomerulonephritis.
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PMID:Involvement of hemostasis during an autoimmune glomerulonephritis induced by mercuric chloride in brown Norway rats. 622 1

Coagulation factor Xa is a plasma serine protease that catalyzes prothrombin to thrombin conversion, which, in turn, leads to the generation of the fibrin clot. Of the several parameters that govern the plasma level of factor Xa, control of its catabolism is of crucial importance. However, little is known regarding the mechanisms by which factor Xa is catabolized. In the present study we examine the cellular basis for the uptake and degradation of factor Xa. 125I-Factor Xa was degraded by hepatoma cells and embryonic fibroblasts via a process which required cell surface-bound tissue factor pathway inhibitor (TFPI), a potent inhibitor of factor Xa. Uptake and degradation of cell surface-bound 125I-TFPI was also markedly stimulated in response to factor Xa binding. The intracellular kinetics of 125I-factor Xa and cell surface-bound 125I-TFPI display a strikingly similar pattern, suggesting that factor Xa and cell surface-bound TFPI are taken up as a bimolecular complex. Using cell lines either deficient in low density lipoprotein receptor-related protein, an endocytic receptor that mediates the degradation of uncomplexed TFPI (Warshawsky, I., Broze, G.J., Jr., and Schwartz, A.L. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 6664-6668), or deficient in tissue factor (TF), an integral membrane protein capable of forming quarternary complexes with factor Xa, TFPI, and factor VIIa, we demonstrated that the receptor that mediates the uptake and degradation of factor Xa-TFPI complex was neither low density lipoprotein receptor-related protein nor TF. As the vascular endothelial cell surface retains a substantial pool of TFPI (Sandset, P.M., Alildgaard, U., and Larsen, M.L. (1988) Thromb. Res. 50, 803-813; Novotny, W.F., Brown, S.G., Miletich, J.P., Rader, D.J., and Broze, G.J., Jr. (1991) Blood 78, 387-393), our data suggest that endothelial cell surface TFPI may be actively involved in the clearance of factor Xa from the circulation via mediated uptake and degradation.
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PMID:Receptor-mediated endocytosis of coagulation factor Xa requires cell surface-bound tissue factor pathway inhibitor. 862 21

Kininogens have recently been shown to possess antiadhesive, anticoagulant, and profibrinolytic properties and can inhibit platelet activation at low thrombin concentrations. To test whether kininogens have antithrombotic properties in vivo, we devised a model of limited arterial injury confined to removal of the endothelium. Brown-Norway Katholiek strain rats with an absence of low- and high-molecular-weight kininogen due to a single point mutation, A163T, were compared in the thrombosis model to the wild-type animals, which were otherwise genetically identical. Despite an equivalent vascular injury, the mean time (+/-SEM) for a 90% decrease in flow measured by laser Doppler was 38.4+/-17 minutes in the kininogen-deficient rats compared with 194+/-29 minutes in the wild-type animals (P<0.002). The degree of vascular injury was the same. No evidence for disseminated intravascular coagulation (decrease in factor V, antithrombin, or fibrinogen) or excessive fibrinolysis (elevation of fibrinogen degradation products) was found in either group of animals. The results suggest that kininogens have antithrombotic properties at low concentrations of thrombin and that inhibitory peptides derived from kininogen may constitute a new antithrombotic strategy.
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PMID:Kininogens are antithrombotic proteins In vivo. 1047 69

Thrombin induces astrocytoma cell rounding through a Rho-dependent pathway (Majumdar, M., Seasholtz, T. M., Goldstein, D., de Lanerolle, P., and Brown, J. H. (1998) J. Biol. Chem. 273, 10099-10106). The involvement of the G(12) family of G proteins and the role of specific Rho exchange factors in transducing signals from the thrombin receptor to Rho-dependent cytoskeletal responses was examined. Microinjection of cDNAs for activated Galpha(12) or Galpha(13) induced cell rounding, and antibodies to Galpha(12) or Galpha(13) blocked the response to thrombin. In contrast, activation or inhibition of Galpha(q) function had relatively little effect. The cytoskeletal response to Galpha(12) was inhibited by microinjection of C3 exoenzyme, indicating Rho dependence. Two Rho-specific guanine nucleotide exchange factors (GEFs), oncogenic lbc and p115, increased the percentage of rounded cells 4-5-fold, and this was inhibited by C3. Mutant GEFs lacking the Dbl homology (DH) domain required for exchange factor activity failed to induce cell rounding. However, the DH mutants of lbc and p115 were efficacious inhibitors of rounding induced by thrombin or Galpha(12). The effects of lbc were dependent on an intact pleckstrin homology domain, which may be required for appropriate targeting of the Rho-GEF. These findings identify the Galpha(12) protein family as transducers of thrombin signaling to the cytoskeleton and provide the first evidence that a Rho-GEF transduces signals between G protein-coupled receptors and Rho-mediated cytoskeletal responses.
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PMID:A rho exchange factor mediates thrombin and Galpha(12)-induced cytoskeletal responses. 1048 Aug 88

The serine protease uPA (urokinase-type plasminogen activator) and its receptor uPAR (CD87) are often elevated in malignant tumours, hence, inhibition of this tumour-associated plasminogen activation system provides an attractive target for therapeutic strategies. WX-UK1, a derivative of 3-aminophenylalanine in the L-conformation with inhibitory antiproteolytic properties, was tested for its specificity spectrum using specific chromogenic paranitroanilide peptide substrates. The corresponding D-enantiomer of WX-UK1 was used as a control. The anti-tumour and anti-metastatic (number of lung foci and weight of the axillary lymph nodes) properties were studied by subcutaneous administration of WX-UK1 to Brown Norwegian (BN) rats carrying orthotopically transplanted BN472 rat breast tumours. WX-UK1 selectively inhibited tumour-related proteases from rats and humans such as uPA, plasmin, or thrombin in the sub or low micromolar range. The activity was stereoselective as the D-enantiomer of WX-UK1 inhibited uPA and plasmin at approximately 70-fold higher Ki values than the active L-form. Chronical administration of the L-enantiomer of WXUK1 impaired primary tumour growth and metastasis of BN472 rat breast cancer in a dose-dependent manner. The minimum inhibitory dosage with maximal effect was between 0.15 and 0.3 mg/kg/day. The inactive D-enatiomer of WX-UK1 was not active in this respect. Daily treatment with WX-UK1 for up to 35 days was well tolerated as judged by the unchanged body and organ weight development. In conclusion, our results provide evidence that WX-UK1 as a single agent inhibits breast tumour growth and metastasis in vivo, and thus is a promising candidate drug to treat human cancer.
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PMID:Suppression of rat breast cancer metastasis and reduction of primary tumour growth by the small synthetic urokinase inhibitor WX-UK1. 1584 27

Venom-induced consumption coagulopathy occurs in snake envenoming worldwide but the interaction between procoagulant snake venoms and human coagulation remains poorly understood. We aimed to evaluate an assay using endogenous thrombin potential (ETP) to investigate the procoagulant properties of a range of Australian whole venoms in human plasma and compared this to traditional clotting and prothrombinase activity studies. We developed a novel modification of ETP using procoagulant snake venoms to trigger thrombin production. This was used to characterise the relative potency, calcium and clotting factor requirements of five important Australian snake venoms and efficacy of commercial antivenom, and compared this to prothrombinase activity and clotting assays. All five venoms initiated thrombin generation in the absence and presence of calcium. Pseudonaja textilis (Brown snake; p<0.0001), Hoplocephalus stephensii (Stephen's-banded snake; p<0.0001) and Notechis scutatus (tiger snake; p=0.0073) all had statistically significant increases in ETP with calcium. Venom potency varied between assays, with ETP ranging from least potent with Oxyuranus scutellatus (Taipan) venom to intermediate with N. scutatus and H. stephensii venoms to most potent with P. textilis and Tropidechis carinatus (Rough-scale snake) venoms. ETPs for N. scutatus, T. carinatus and H. stephensii venoms were severely reduced with factor V deficient plasma. Antivenom neutralized the thrombin generating capacity but not prothrombin substrate cleaving ability of the venoms. Contrary to previous studies using clotting tests and factor Xa substrates, these venoms differ in calcium requirement. ETP is a useful assay to investigate mechanisms of other procoagulant venoms and is a robust method of assessing antivenom efficacy.
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PMID:Endogenous thrombin potential as a novel method for the characterization of procoagulant snake venoms and the efficacy of antivenom. 2033 89

The prothrombinase complex, composed of the protease factor (f)Xa and cofactor fVa, efficiently converts prothrombin to thrombin by specific sequential cleavage at 2 sites. How the complex assembles and its mechanism of prothrombin processing are of central importance to human health and disease, because insufficient thrombin generation is the root cause of hemophilia, and excessive thrombin production results in thrombosis. Efforts to determine the crystal structure of the prothrombinase complex have been thwarted by the dependence of complex formation on phospholipid membrane association. Pseutarin C is an intrinsically stable prothrombinase complex preassembled in the venom gland of the Australian Eastern Brown Snake (Pseudonaja textilis). Here we report the crystal structures of the fX-fV complex and of activated fXa from P textilis venom and the derived model of active pseutarin C. Structural analysis supports a single substrate binding channel on fVa, to which prothrombin and the intermediate meizothrombin bind in 2 different orientations, providing insight into the architecture and mechanism of the prothrombinase complex-the molecular engine of blood coagulation.
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PMID:Crystal structure of the prothrombinase complex from the venom of Pseudonaja textilis. 2413 80


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