Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by the synthesis of antinuclear antibodies. Nucleosomes-the disc-like-structural unit of chromatin being composed of histones and DNA-are the primary antigenic structure that induces the formation of complement-activating antigen-antibody complexes in basement membranes. The autoreactivity in SLE has been elucidated in drug-induced SLE: Hypomethylation of DNA leads to overexpression of integrin CD 11a/CD 18, increased binding of T-cells to macrophages and B-cells, a higher rate of apoptosis of macrophages and elevated B-cell activity with consecutive production of autoantibodies. Disturbances of apoptosis (e.g. mutation of Fas gene) are relevant also in non drug-induced SLE. The morphologic diagnosis-by light microscopy, immunohistology and electron microscopy-of skin and renal biopsies can confirm the diagnosis and help in prognostic assessment as well as therapeutic decisions in SLE. The value of the morphologic diagnosis in SLE is enhanced by reporting semiquantitative scores of disease activity and chronicity. The antiphospholipid syndrome (APS) is characterized by thrombosis, thrombocytopenia, recurrent fetal loss and antiphospholipid antibodies. APS associated with SLE or other systemic autoimmune diseases has been termed secondary APS. Antibodies in APS are directed against phospholipids and phospholipid-protein complexes. One of these proteins is beta 2-glycoprotein 1. An important mechanism of the increased rate of thrombosis in APS is probably the inhibition of the protein C catalyzed inactivation of clotting factors V and VIII. Venous thrombosis with recurrent pulmonary emboli and arterial thrombi in brain, heart and kidney (thrombotic microangiopathy) can lead to divergent clinical manifestations in APS.
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PMID:[Systemic lupus erythematosus and antiphospholipid syndrome]. 906 4

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by the synthesis of antinuclear antibodies. Nucleosomes- the disc-like structural units of chromatin, composed of histones and DNA-are the primary antigenic structure that induces the formation of complement-activating antigen-antibody complexes in basement membranes. The autoreactivity in SLE has been elucidated in drug-induced SLE: hypomethylation of DNA leads to overexpression of integrin CD11a/ CD18, increased binding of T-cells to macrophages and B-cells, a higher rate of apoptosis of macrophages, and elevated B-cell activity with consecutive production of autoantibodies. Disturbances of apoptosis (e.g. mutation of Fas gene) are relevant also in non-drug-induced SLE. The morphologic diagnosis-by light microscopy, immunohistology and electron microscopy-of skin and renal biopsies can confirm the diagnosis and help in prognostic assessment as well as therapeutic decisions in SLE. The value of the morphologic diagnosis in SLE is enhanced by reporting semiquantitative scores of disease activity and chronicity. The antiphospholipid syndrome (APS) is characterized by thrombosis, thrombocytopenia, recurrent fetal loss and antiphospholipid antibodies. APS associated with SLE or other systemic autoimmune diseases has been termed secondary APS. Antibodies in APS are directed against phospholipids and phospholipid-protein complexes. One of these proteins is beta 2-glycoprotein 1. An important mechanism of the increased rate of thrombosis in APS is probably the inhibition of the protein C-catalyzed inactivation of clotting factors V and VIII. Venous thrombosis with recurrent pulmonary emboli and arterial thrombi in brain, heart and kidney (thrombotic microangiopathy) can lead to divergent clinical manifestations in APS.
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PMID:[Systemic lupus erythematosus and antiphospholipid syndrome]. 908 61

Thrombomodulin (TM) is an endothelial surface glycoprotein that acts as a natural anticoagulant. It inhibits thrombin and accelerates the activation of the anticoagulant protein C. TM has been detected in dermal keratinocytes, where it is associated with terminal differentiation. It can also be detected in various types of squamous malignant neoplasms and in malignancies of endothelial and mesothelial origin, such as Kaposi's sarcoma or malignant mesothelioma, but is absent in pulmonary adenocarcinomas (AC). Seventy-two lung tumour specimens [33 squamous cell carcinomas (SQCC), 23 AC, 1 large cell carcinoma, 8 small cell lung cancers (SCLC) and 7 multidifferentiated tumours (MT)] were analysed immunohistochemically by staining with an anti-TM antibody in order to assess TM expression. All of the SQCC stained positively for TM. In contrast, only 9 AC and 4 MT and none of the SCLC showed positive anti-TM staining. Seven hyperplastic bronchial epithelial specimens and eight preneoplastic bronchial lesions (five cases of moderate dysplasia, two cases of severe dysplasia and one case of carcinoma in situ) were used as controls. Normal or hyperplastic areas of bronchial epithelium revealed no positive reaction. However, a distinct positive anti-TM staining pattern related to the degree of keratiniziation of dysplastic lesions was seen. The present results suggest that anti-TM immunostaining is a useful marker for squamous cell carcinoma in the differential diagnosis of pulmonary carcinoma, also indicating keratinocyte differentiation in dysplastic bronchial epithelium.
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PMID:Expression and localization of thrombomodulin in preneoplastic bronchial lesions and in lung cancer. 909 77

Hemodynamic forces modulate various endothelial cell functions even in the presence of cytokines under gene regulation. We have investigated the effect of shear stress on the coagulation and fibrinolysis systems in cultured human umbilical vein endothelial cells (HUVECs) perturbed by cytokines, using modified cone-plate viscometer. Thrombomodulin (TM), a surface glycoprotein receptor for thrombin that catalyzes the activation of the protein C anticoagulant pathway, and tissue factor (TF), a transmembrane glycoprotein that plays a central role in blood coagulation, are important regulators for coagulation in endothelium. Shear stress of 18 dynes/cm2 increased the expression of TM either in the presence or absence of TNF alpha (100 U/ml). In contrast, shear stresses of 6 approximately 24 dynes/cm2 decreased the expression of TNF alpha-induced TF in a shear intensity- and exposure time- dependent manner Tissue plasminogen activator(t-PA), which converts plasminogen to plasmin to degrade fibrin clot, and plasminogen activator inhibitor-1 (PAI-1), which inhibits t-PA function, play central roles in fibrinolysis in the endothelium. Treatment of the cells with IL-1 beta or TNF-alpha under static conditions had no effect on t-PA secretion, while release of PAI-1 increased. When cells were exposed to increasing shear stress up to 24 dynes/cm2, levels of t-PA significantly increased relative to shear stress, while PAI-1 secretion decreased gradually. In the presence of IL-1 beta or TNF-alpha, the increased production of t-PA was further augmented. These results clearly indicate that shear forces act as an important regulators of the coagulation and fibrinolysis systems in endothelium, to maintain antithrombogenicity of blood vessels.
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PMID:[Regulation of antithrombogenicity in endothelium by hemodynamic forces]. 913 94

"Antiphospholipid" antibodies (aPL) are a heterogenous group of autoantibodies with clinical importance because of their association with thrombotic events, both venous and arterial. Traditionally, aPL have been assayed using phospholipid-dependent tests and are classified as lupus anticoagulants and anticardiolipin antibodies (ACA), based on the method of detection. Most antibodies associated with the aPL syndrome and detected in standard assays are actually directed against two phospholipid-binding plasma proteins, beta 2 glycoprotein I and prothrombin. These antibodies can also be detected in immunoassays (ELISA) utilizing purified protein antigens, in the absence of phospholipids. The main advantage of beta 2 GPI-ELISA compared with conventional cardiolipin-ELISA appearing from initial clinical studies is greater specificity for the aPL syndrome, due to (i) ignorance of "authentic" ACA that interact directly with cardiolipin; (ii) detection of species specific anti-beta 2 GPI antibodies poorly reactive with bovine beta 2 GPI in the cardiolipin-ELISA. Other proteins proposed as target antigens of aPL are protein C, protein S, annexin V, high- and low-molecular weight kininogens, the latter being involved in the binding of antibodies to phosphatidylethanolamine. The possibility that particular autoantibodies (or combinations of autoantibodies) explain the observed clinical spectrum of the aPL syndrome is attractive, but much remains to be learned about their pathogenicity and origin in order to improve diagnosis and therapy.
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PMID:[New targets of antiphospholipid antibodies]. 916 56

Monoclonal components are usually found in elderly patients. They are rarely noted in children, both because of their slight presence, and because the very low concentration makes it difficult to single them out. This report is about the identification of a transitory IgG lambda monoclonal component in a 17 day old baby suffering from aureus Staphylococcus. Electrophoresis was carried out with automatic equipment on cellulose acetate; immunofixation with a manual method on agarose gel; the quantitative doses of the immunoglobulins, reactive protein C and alpha 1-acid glycoprotein with nephelometric technique, the erythrocyte sedimentation rate with automatic equipment. The importance of singling out monoclonal components in children must be emphasized, inasmuch as it may be a sign of an immunological disorder, usually benign and transitory, but sometimes extremely serious.
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PMID:[Presence of a monoclonal component IgG lambda in a 17-day-old newborn with omphalitis caused by Staphylococcus aureus]. 931 48

Factor V is a single chain glycoprotein that plays an essential role in the regulation of blood coagulation. After initiation of coagulation, factor V is converted into factor Va through limited proteolysis. Factor Va acts as protein cofactor in the prothrombin-activating complex, which is comprised of the serine protease factor Xa, Ca2+ ions and a procoagulant membrane surface. Factor Va accelerates factor Xa-catalysed conversion of prothrombin into thrombin more than 10(4)-fold. The cofactor activity of factor Va in prothrombin activation is down-regulated by activated protein C (APC). The physiological importance of this regulatory pathway is demonstrated by the occurrence of hereditary thrombophilia in individuals with a genetic defect that makes factor Va less sensitive to proteolytic inactivation by APC (APC resistance).
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PMID:Factor V. 943 74

Protein S is a vitamin K-dependent glycoprotein involved in the regulation of the anticoagulant activity of activated protein C (APC). Also, an anticoagulant role for protein S, independent of APC, has been described. Protein S has a unique C-terminal sex hormone binding globulin (SHBG)-like domain that represents about half of the molecule. To define the role of this domain in APC cofactor activity and in binding to C4b-binding protein (C4BP), we have constructed a recombinant protein S molecule of N-terminal residues 1-242 that lacks the SHBG domain (mini-protein S). A panel of monoclonal antibodies directed against the N-terminal region of protein S recognized plasma-derived protein S, wild-type recombinant protein S and mini-protein S with similar affinities, whereas a monoclonal antibody that recognizes an epitope in the SHBG domain did not detect mini-protein S. Mini-protein S did not bind to C4BP in a solid-phase binding assay, and the cofactor activity of mini-protein S was not inhibited by preincubation with C4BP. In a plasma coagulation assay, the cofactor activity of mini-protein S was lower than wild-type or plasma-derived preparations. In contrast, no difference in APC cofactor activities was observed when the preparations were tested in purified systems that monitor the APC-mediated degradation of factors Va or VIIIa. In conclusion, we constructed a protein S molecule that fails to bind C4BP and still displays cofactor activity for APC. This confirms the role of the C-terminal SHBG region in C4BP binding and demonstrates that N-terminal residues 1-242 are sufficient for the expression of APC cofactor activity in a system using purified components. In plasma, however, the C-terminal SHBG region plays a role in the expression of optimal APC cofactor activity.
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PMID:Characterization of mini-protein S, a recombinant variant of protein S that lacks the sex hormone binding globulin-like domain. 946 35

Thrombomodulin (TM) is an anticoagulant glycoprotein on the surface of endothelial cell that directly inhibits the procoagulant activities of thrombin, and the TM-thrombin complex accelerates thrombin-catalyzed activation of protein C. Soluble TM in urine has no glycosaminoglycan (GAG) chain which accelerates the anticoagulant activities. Therefore, we expressed recombinant GAG-modified urinary thrombomodulin (GAG-UTM) in C127 cells. The glycosylation sites were determined by amino acid sequence analysis of peptides digested with trypsin after S-carboxymethylation. The structures of N-linked oligosaccharides were estimated by two-dimensional sugar mapping of pyridylaminated oligosaccharides that were treated with exoglycosidase. The disaccharide composition analysis of the GAG chain was performed by HPLC using digestion with chondroitinase ABC, ACII and B. Consequently, it was revealed that the N-linked oligosaccharides were assigned to Asn29, Asn98, Asn364, Asn391; those structures were estimated biantennary, 2-6 branched triantennary and 2-4 branched triantennary complex type oligosaccharides that were linked by fucose at the ratio of 1.0:0.5:0.1, respectively. Moreover, the attachment site of the GAG chain was assigned to Ser472. It was then estimated that the GAG chain contained chondroitin-4-sulfate and dermatan sulfate, which were repeated approximately 30 times. In this paper, the GAG attachment site and structural characteristics of GAG-UTM, were confirmed. Moreover, structures of the N-linked oligosaccharides of GAG-UTM are described for the first time.
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PMID:The glycosylation sites and structural characteristics of oligosaccharides on recombinant human thrombomodulin. 959 55

The trisaccharide allyl glycoside 36 and related disaccharide part structures have been prepared using the 2-trichloroacetamido-2-deoxy-alpha-D-galactopyranosyl trichloroacetimidate derivative 9 as glycosyl donor under promotion with TMSOTf or Sn(OTf)2, respectively, to produce the beta-(1-->4) linkage to suitably protected glucosamine derivatives in fair yields. Fucosylation was effected employing the ethyl 1-thio glycosyl donor 20 in the presence of IDCP. Deprotection of the intermediates afforded the disaccharide allyl glycosides beta-D-GalpNAc-(1-->4)- beta-D-GlcpNAc 13, beta-D-GalpNClAc-(1-->4)-beta-D-GlcpNAc 14, alpha-L-Fucp-(1-->3)-beta-D-GlcpNAc 24, alpha-L-Fucp-(1-->4)-beta-D- GlcpNAc 31 and the branched trisaccharide allyl glycoside beta-D-GalpNAc-(1-->4)[alpha-L-Fucp-(1-->3)]-beta-D-GlcpNAc 36. The trisaccharide which corresponds to a structural motif occurring in N-glycoprotein glycans from human urokinase, human recombinant protein C, phospholipase A2 as well as O-glycans, was converted into a neoglycoprotein following introduction of a cysteamine-derived spacer group and subsequent activation with thiophosgene.
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PMID:Synthesis of a neoglycoprotein containing the Lewis X analogous trisaccharide beta-D-GalpNAc-(1-->4)[alpha-L-Fucp-(1-->3)]-beta-D-GlcpNAc. 971 24


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