Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 38-year-old patient with cerebral P. falciparum malaria was admitted 12 days after a short trip to Kenya. The serum level of tumor necrosis factor (TNF-alpha) was elevated (251 pg/ml). In contrast, Protein C (plasma activity 36.1%; antigen concentration 31.7%) and protein C inhibitor 1 (activity 0.55 U/ml) levels were decreased. This suggested a state of functional activation of the clotting system which was confirmed by elevated levels (4.8 ng/ml) of circulating thrombin-antithrombin-III-complexes (TAT). Protein S (total and free) and coagulation factor IX levels were within normal range. Under successful antiparasitic therapy, TNF-alpha as well as protein C and protein C inhibitor 1 levels returned to baseline within one week. In the context of other studies that demonstrate procoagulant effects of TNF-alpha, it is remarkable that in the case of complicated P. falciparum malaria, an elevated concentration of TNF-alpha can be paralleled by a decreased plasma level of protein C and an increase in TAT suggesting a procoagulant state.
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PMID:[Malaria tropica with activation of blood coagulation and detection of tumor necrosis factor (NF-alpha) in serum]. 215 19

Glycosyl phosphatidylinositol (GPI)-anchored membrane proteins are deficient in the blood cells affected by paroxysmal nocturnal hemoglobinuria (PNH). The relation of the deficiencies of CD59 and CD14 with the clinical features of PNH are reported. CD59 binds to complement components C8 and C9 derived from human sera and inhibits the C5b-9-mediated hemolysis in a species-selective manner. The CD59-binding sites were revealed to be localized in the alpha subunit of C8 and in the "b" domain of C9 (thrombin fragment). The deficiency of CD59 in PNH is causatively related to the hemolytic features in PNH. A monocyte differentiation antigen, CD14, is deficient in the affected PNH monocytes. CD14 is reported to be one of the receptors to lipopolysaccharide (LPS). LPS-binding to the monocytes were revealed to be mediated through CD14 on monocytes. Enhancement of LPS-binding to monocytes by the presence of serum was not seen to PNH-affected monocytes. PNH-affected monocytes showed impaired TNF-alpha production in response to LPS. The deficiency of CD14 indicates the abnormality in PNH-affected monocytes, however, its significance in the clinical features of PNH is to be clarified.
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PMID:[Clinical features and diagnosis of paroxysmal nocturnal hemoglobinuria: correlates with the deficiency of GPI-anchored membrane proteins]. 751 13

P-selectin is an endothelial cell adhesion molecule which mediates the binding of neutrophils and monocytes. Its appearance at the cell surface can be induced within minutes by histamine and thrombin which rapidly stimulate the transport of P-selectin from intracellular storage granules to the plasma membrane. We have recently found a second regulation mechanism for P-selectin on mouse endothelioma cells. Like E-selectin, P-selectin is also regulated at the level of transcription. Both selectins are induced by LPS or TNF-alpha with a maximal expression level at the cell surface 3-4 h after stimulation. Here, we report that this up-regulation of the synthesis of P-selectin also occurs in vivo in endothelium of the mouse. Analysing brain tissue, which is devoid of constitutive expression of P-selectin, we found that LPS and also TNF-alpha strongly induce the expression of P-selectin on all venular endothelial cells of the leptomeninges and, at a weaker level, on some blood vessels of the brain parenchyma. Induction of P-selectin expression could also be observed in tissues, such as the tongue, where P-selectin is constitutively expressed on small venules but only rarely on larger venules. Strong staining for P-selectin on endothelium of all large venules was observed in tissues of LPS and TNF-alpha treated animals and staining for this newly synthesized P-selectin was enriched at the luminal surface of these cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression of P-selectin on endothelial cells is upregulated by LPS and TNF-alpha in vivo. 752 54

Ovine tumour necrosis factor-alpha (OvTNF-alpha) was cloned by reverse transcription-polymerase reaction using RNA isolated from lipopolysaccharide (LPS)-stimulated alveolar macrophages and primers based on the human TNF-alpha cDNA sequence. An expression vector carrying the coding sequence of the mature form of ovine TNF was constructed. The recombinant Ov-TNF alpha (rOvTNF-alpha) was expressed as a glutathione-S-transferase (GST) fusion protein. It was cleaved with thrombin to yield rOvTNF free of the GST moiety. Growth at a lower temperature of 30 degrees C and use of Escherichia coli strains AM207, AM305, E392 and NM522 did not improve the recovery of rOvTNF-alpha from the soluble fraction to a significant extent. Purification of recombinant proteins was achieved rapidly and easily by affinity chromatography using glutathione-Sepharose. Yields of pure rOvTNF-alpha achieved in E. coli JM109 and AM207 were approximately 1 mg L-1. Both rOvTNF-alpha and recombinant human TNF-alpha (rhTNF-alpha) exerted cytotoxicity on L929 cells. However, rOvTNF-alpha but not rhTNF-alpha stimulated proliferation of ovine thymocytes. Maximum levels of TNF-alpha mRNA expression by LPS-stimulated ovine alveolar macrophages were detected at approximately 4 h post-stimulation.
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PMID:Expression, biological activity and kinetics of production of recombinant ovine TNF-alpha. 753 48

The blood coagulation and fibrinolysis of 33 patients with compensated liver cirrhosis and 31 patients with hepatocellular carcinoma were examined using several markers, namely thrombin-antithrombin III complex (TAT), plasmin-alpha 2 plasmin inhibitor complex (PIC), antithrombin-III (AT-III) and prothrombin time, and the relationship between these markers, endotoxemia, and TNF-alpha was examined. These patients had no complications due to hepatic failure, such as infections, encephalopathy, ascites, G-I bleeding and clinical DIC. PIC was not elevated, but TAT tended to be elevated in LC and significantly elevated in HCC. AT-III was decreased in LC and HCC, and the blood endotoxin was partly positive in LC and HCC, but was not correlated with AT-III or PT. The TAT level in the blood-endotoxin-positive patients measured by endospecy methods was higher than that in the negative patients, and was significantly correlated with the blood endotoxin level in the LC and HCC patients (r = 0.57, r = 0.88, p < 0.01). No relationship was observed between TNF-alpha and blood endotoxin. In conclusion, (1) blood coagulability was activated already in compensated LC and HCC, but was not connected with fibrinolysis, (2) the activation of coagulability was closely related with endotoxemia, and (3) TNF-alpha was not correlated with blood endotoxin or TAT.
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PMID:[Blood coagulation and fibrinolysis in relation to endotoxemia in liver cirrhosis and hepatocellular carcinoma]. 756 21

Fibrosis of the pulmonary parenchyma is a frequent and serious complication of scleroderma (systemic sclerosis, SSc), resulting in significant morbidity and mortality. During the past decade data have accumulated in support of an inflammatory process affecting the alveoli and distal airways that culminates in irreversible fibrosis in many SSc patients. Recent findings indicate the presence of lung fibroblasts with altered phenotype and biologic activity (myofibroblasts), perhaps arising from the influence of cytokines on resident lung fibroblasts. Acute-phase inflammatory cytokines such as IL-1 alpha, TNF-alpha, MIP-1 alpha, IL-8 and RANTES are increased in SSc bronchoalveolar lavage (BAL) fluid, as is thrombin, a potent mitogen for lung fibroblasts. Chronic-phase inflammatory and fibrogenic cytokines such as PDGF and TGF-beta are also present in increased amounts in SSc BAL fluid. The inciting event(s) and the process(es) leading to the perpetuation of fibrosis in SSc are unknown. Treatment of SSc lung disease has been empiric and generally disappointing, and it is likely that effective treatment awaits a better understanding of the biological events that regulate collagen and other extracellular matrix synthesis.
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PMID:Interstitial lung disease of systemic sclerosis. 765 Apr 24

The plasminogen activator inhibitor PAI-1 is markedly elevated in vivo and in vitro upon exposure to the inflammatory mediators tumor necrosis factor alpha (TNF alpha), interleukin-1 (IL-1), and bacterial lipopolysaccharide. Here we report that the isoflavone compound genistein prevents the increase in synthesis of PAI-1 induced by these inflammatory mediators in human endothelial cells in vitro, and partially reduces the basal PAI-1 production by these cells. These effects of genistein were accompanied by a decrease in PAI-1 mRNA and in a suppression of the PAI-1 transcription rate as shown by run-on assay. A specific action of genistein, probably by inhibiting a tyrosine protein kinase, is likely, because the structural genistein analogue daidzein, which has a low tyrosine protein kinase inhibitor activity, did not inhibit PAI-1 synthesis. Vanadate, a tyrosine protein phosphatase inhibitor, increased PAI-1 production. The effect of genistein on PAI-1 synthesis was rather selective. Herbimycin A also reduced PAI-1 synthesis, but several other tyrosine protein kinase inhibitors, namely tyrphostin A47, methyl-2,5-dihydroxy-cinnamate, and compound 5, were unable to do so. All these tyrosine protein kinase inhibitors reduced basic fibroblast growth factor (b-FGF)-induced [3H]thymidine incorporation in endothelial cells. This indicates that the effect of genistein on PAI-1 transcription proceeds independently of its effect on mitogenesis. In contrast to TNF-alpha-induced PAI-1 production, the transcription and synthesis of urokinase-type plasminogen activator (u-PA) was not inhibited by genistein. A TNF-alpha-mutant (Trp32Thr86TNF alpha) that specifically recognizes the 55-kD TNF-receptor, mimicked the effects of TNF alpha on both PAI-1 and u-PA. Because genistein affected PAI-1, but not u-PA induced by this mutant, involvement of different TNF-receptors cannot underlie the difference in the effects of genistein on PAI-1 and u-PA synthesis. Because genistein also inhibited PAI-1 induction by thrombin and IL-4, it is likely that genistein does not act on a TNF alpha-receptor-coupled protein kinase but on the signal transduction pathway enhancing PAI-1 transcription. Our results suggest that the TNF alpha-induced signal transduction pathway of PAI-1 transcription involves a genistein-sensitive step that is not involved in the induction of u-PA by TNF alpha. Given the limited sensitivity to several other tyrosine protein kinase inhibitors, this genistein-sensitive step may be a potential target for pharmacologic intervention to reduce elevated plasma PAI-1 levels.
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PMID:Genistein reduces tumor necrosis factor alpha-induced plasminogen activator inhibitor-1 transcription but not urokinase expression in human endothelial cells. 794 70

TNF-alpha induces changes in endothelial cell functions, such as upregulation of tissue factor, resulting in endothelial procoagulant activity which may play a role in disseminated intravascular coagulation. The procoagulant activity of TNF-alpha-stimulated endothelial cell monolayers was studied in a human ex vivo native (nonanticoagulated) blood flow system using the three thrombin inhibitors recombinant hirudin, Ro 46-6240, and heparin. Under venous blood flow conditions (shear rate 65 s-1) recombinant hirudin, Ro 46-6240, and heparin inhibited fibrin deposition on the endothelial cells by 50% at concentrations of 14, 28, and 412 ng/ml, respectively. The highest tested concentrations of the thrombin inhibitors reduced the postchamber fibrinopeptide A levels from 713 +/- 69 to < 70 ng/ml. Surprisingly, even at relatively high inhibitor concentrations, some local fibrin deposits were found on TNF-alpha-stimulated cells, suggesting that some endothelial cells possess higher procoagulant activity than others. Therefore, the surface expression pattern of tissue factor, the primary initiator of coagulation in this system, was examined by immunogold-silver staining. The results showed that the tissue factor density on the cell surface varied strongly among TNF-alpha-stimulated endothelial cells. Using TNF receptor-selective agonistic mutants of TNF-alpha, it was demonstrated further that the heterogenous surface expression of tissue factor was mediated entirely by the 55-kD TNF receptor and did not involve the 75-kD TNF receptor. We conclude that in this system TNF-alpha induces heterogenous tissue factor expression which may lead to a high local thrombin concentration, such that even in the presence of thrombin inhibitors focal fibrin deposition occurs.
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PMID:Endothelial cells stimulated with tumor necrosis factor-alpha express varying amounts of tissue factor resulting in inhomogenous fibrin deposition in a native blood flow system. Effects of thrombin inhibitors. 818 39

The interaction of blood-borne lymphocytes with blood vascular endothelial cells is a fundamental component of lymphocyte circulation. The role of lymphatic endothelial cells is less certain. These studies describe the isolation, characterization and lymphocyte binding capacity of efferent lymphatic endothelial cells from ovine mesenteric lymphatic vessels. Lymphatic endothelial cells had anti-thrombin 3, von Willebrand Factor and MHC I on their surface. The cells also actively metabolized acetylated low density lipoprotein. The morphological appearance was indistinguishable from blood vascular endothelium but quite different from cultured smooth muscle cells. Lymphocyte binding to lymphatic endothelial cells was not significantly different from binding to carotid artery or jugular vein endothelial cells. The degree of binding in all cases could be enhanced by incubating endothelial cells in medium containing rh TNF-alpha (recombinant human tumor necrosis factor alpha).
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PMID:Characterization of ovine lymphatic endothelial cells and their interactions with lymphocytes. 820 71

Endothelial cells lining the vasculature participate in a variety of physiological processes. Following cell activation, functional changes are accompanied by changes in the surface structure (or phenotype) of these cells. Studies to date have tended to concentrate on selective changes induced with one or two surface molecules. The following study uses a different approach, having assessed potential changes to the endothelial cell surface using a large number (> 120) of previously untested monoclonal antibodies, and the cytokines TNF-alpha and gamma-IFN, as well as the proteolytic enzyme thrombin. Antibody representatives from all cluster of differentiation groups CD1 through to CD54 were assessed in these studies, which used human umbilical vein endothelial cells. In line with previous observations, antibodies within CD9, CD13, CD26, CD29, CD31, CD34, CD44, CD46, CD47, CD49, CD51 and CD54 gave significant and consistent reactivity using non-stimulated ('quiescent') endothelium. Using parallel cells differentially stimulated with TNF-alpha, gamma-IFN or thrombin, antibodies within CD1 through to CD15, CDw17 to CD19, CD21 to CD23, CD26, CD27, CD29, CD30, CD33 to CD35, CD37, CD38, CD40, CD43 to CD46, CD48, CD51 to CD53 failed to provide any consistent alteration to reactivity patterns compared to non-stimulated cells. There did, however, appear to be some activation induced changes using antibodies within the other CD groups (i.e. CD16, CD20, CD24, CD25, CD28, CD31, CD32, CD36, CD39, CD41, CD42, CD47, CD49, CD50 and CD54) which ranged from minor to significant in scope and magnitude.
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PMID:Differential expression of surface antigens on activated endothelium. 831 84


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