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)

Tamoxifen has been implicated as a risk factor for venous thrombosis in advanced breast cancer although the evidence for increased arterial or venous thrombosis with tamoxifen in early breast cancer is less clear. The effect of tamoxifen on haemostasis, and thereby possible thromboembolic risk, was investigated in normal women enrolled in a placebo controlled trial of tamoxifen as a chemopreventative agent for breast cancer. There was an initial reduction in fibrinogen levels in all women on tamoxifen over the first year of follow-up and a marginal reduction in antithrombin III and Protein S in postmenopausal women at 6 months. There were no changes in cross linked fibrinogen degradation products or Protein C for pre or post-menopausal women. There was no increase in the incidence of thromboembolic events on tamoxifen. This study demonstrates that tamoxifen has only marginal effects on factors involved in haemostasis reported to affect the incidence of arterial or venous thromboembolic disease. The follow-up time is relatively short (maximum 36 months) and careful long term follow-up is necessary to detect clinically significant morbidity.
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PMID:Haemostatic changes and thromboembolic risk during tamoxifen therapy in normal women. 141 16

Human protein C is a vitamin K-dependent plasma glycoprotein that circulates as an inactive zymogen. At the endothelial cell surface, thrombin in complex with the integral membrane protein thrombomodulin converts protein C to its active form by specific cleavage of an activation peptide. The activated form of protein C has potent anticoagulant activity as a feedback regulator of thrombin generation (reviewed in refs 4-6), and also has profibrinolytic, anti-ischaemic and anti-inflammatory properties. Protein C is effective in the treatment of model and human thrombotic diseases but, except when it has been used to treat genetic or acquired deficiencies and microvascular thrombosis, it is administered as the activated enzyme, which has a short biological half-life. We have altered two putative inhibitory acidic residues near the thrombin cleavage site, which results in a 30-fold increase in substrate utilization by alpha-thrombin. We combined these changes with a genetically altered glycoform to generate a zymogen protein C with a 60-fold increased cleavage rate by free alpha-thrombin, independent of its cofactor thrombomodulin. We show that this 'proform' of protein C, unlike the natural circulating zymogen, can be activated by thrombin generated in clotting human plasma, resulting in an inhibition of further clot formation. Our data therefore show that we have engineered a site-activated agent, which only has anticoagulant activity when significant amounts of thrombin are being generated.
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PMID:Enhancing protein C interaction with thrombin results in a clot-activated anticoagulant. 143 7

Selected coagulation and fibrinolytic parameters were assessed in 40 insulin dependent diabetes mellitus patients with varying degrees of metabolic control; 30 healthy subjects matched for age and sex formed the control group. Activated Partial Thromboplastin Time, Prothrombin Time, Fibrinogen, Factor VII, Antithrombin III, Protein C, Plasminogen, alpha 2-Plasmin Inhibitor, Plasminogen Activator Inhibitor-1, tissue-Plasminogen Activator were functionally evaluated. Antigenic levels of tissue-Plasminogen Activator, Thrombin-Antithrombin complexes and fibrinolytic specific product B beta 15-42 were also determined. Compared to the control group diabetic patients displayed significantly higher levels of Fibrinogen (p < 0.01), Factor VII (p < 0.01), Thrombin-Antithrombin complexes (p < 0.01) and Plasminogen Activator Inhibitor-1 activity (p < 0.01). Regardless of the normal level of the tissue-Plasminogen Activator-related antigen, diabetic patients had tissue-Plasminogen Activator activity lower than the control group (p < 0.05). Coagulation Factor VII and Thrombin-Antithrombin complexes were increased only in the patients with poor metabolic control (p < 0.01). Activated Partial Thromboplastin Time, Prothrombin Time, Antithrombin III, Protein C, Plasminogen, alpha 2-Plasmin Inhibitor, B beta 15-42 fibrin peptide were found to be in the normal range. Fibrinogen correlated positively with fasting blood glucose (p < 0.05) and Thrombin-Antithrombin complexes with glycosylated haemoglobin (p < 0.05), whereas Factor VII was positively correlated with glycemia (p < 0.01) and glycosylated haemoglobin (p < 0.05). Higher levels of Fibrinogen were found in patients affected by nephropathy (p < 0.005) or neuropathy (p < 0.05). These results demonstrate an impairment of the haemostatic balance in diabetic patients, that is a possible hypercoagulable state, which represents an important factor in the pathogenesis of atherosclerotic complications.
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PMID:Coagulation and fibrinolytic system impairment in insulin dependent diabetes mellitus. 144 May 30

Genetic analysis of a heterozygous protein C-deficient patient revealed a novel deletion of a single guanine residue (8857G) among four consecutive guanine nucleotides [380Trp(TGG)-381Gly(GGT)] in exon IX, which encodes the carboxyl-terminal region of protein C. This deletion results in a frameshift mutation and substitution of the last 39 amino acids (381Gly-419Pro) with 81 abnormal amino acid residues, and we have designated this elongated variant as Protein C-Nagoya. A mutagenic primer was designed which replaced the third guanine residue upstream from the deletion with cytosine, thereby creating a new AvaI site in an otherwise normal allele. Analysis of the polymerase chain reaction products derived from this mutagenic primer showed that the abnormal allele has been inherited in this family. To elucidate how this molecular abnormality leads to protein C deficiency, an expression plasmid containing this mutation was transfected into COS 7, BHK, and psi-2 cells, and the secretory process of the expressed Protein C-Nagoya was analyzed. ELISA and immunoprecipitation analysis with [35S]methionine labeling indicated that the mutant protein C, which was larger in size than normal, was mostly retained within the cells, and only a small portion of it was secreted into the medium. These results suggest that most of Protein C-Nagoya undergoes degradation within the producing cells, and this frameshift mutation apparently leads to protein C deficiency by impairment of secretion of the elongated protein C into plasma.
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PMID:Impaired secretion of the elongated mutant of protein C (protein C-Nagoya). Molecular and cellular basis for hereditary protein C deficiency. 146 96

Of 67 patients with acute deep vein thrombosis of the lower extremity (DVT), 43 patients were treated by venous thrombectomy and 24 patients were managed by conservative treatment. The clinical effect of thrombectomy was evaluated by analyzing follow-up results in the 2 groups. The cumulative incidences of pigmentation and stasis ulcer at the 5th year were 2.7% and 0% respectively in the thrombectomy group, and 24.3% and 10% respectively in the conservative treatment group. Pigmentation and stasis ulcer were significantly more frequent in the conservative treatment group (p < 0.01). It is concluded that venous thrombectomy is superior to conservative treatment to prevent late postthrombotic sequelae. Protein C, protein S and plasminogen were assayed in 40 DVT patients to determine the incidence of hypercoagulable state in DVT. Congenital deficiency or abnormality were found in 15 patients (37.5%). In such DVT patients with thrombophilia anticoagulant prophylaxis should be continued to decrease a risk of rethrombosis.
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PMID:[The treatment of choice in deep vein thrombosis of the lower extremity]. 147 Jan 17

A proper dosage of warfarin after artificial cardiac valve replacements has been determined as an indication of coagulation activity. In some cases, the coagulation activity cannot be maintained within the therapeutic range because Prothrombin time (PT) values deviated from Thrombotest (TT) values. Here we studied each relationship between warfarin concentrations in blood, coagulation activity, vitamin Ks and other coagulation-related agents which were measured in patients administered warfarin after artificial cardiac valve replacements and whose coagulation activity was maintained within a therapeutic range, and in patients whose PT values deviated from TT values. The obtained results were interpreted as follows. 1) There was a high correlation between values from Thromborel S (a clot method) and values from Chromoquick (a method using a synthesized substrate). Since TT values had little variations compared to PT values, the former was an excellent indication of coagulation activity. 2) There was no correlation between warfarin concentrations in blood and coagulation activity in the group in which warfarin concentrations in blood vary within a day (Group B); but there was highly reverse correlation in the group in which warfarin concentrations in blood vary with days (Group A). 3) There was good correlation between warfarin concentrations and PIVKA-II concentrations in blood in Group A. Further, the concentration of Gla-Protein C was one microgram/ml or less on the fourth day from the initiation of warfarin administration. 4) For example, a patient whose PT value of 67% deviated from TT value of 19% on the eleventh day from the initiation of warfarin administration had vitamin K1-epoxide concentration of 2.68 ng/ml and MK-7 concentration of 1.26 ng/ml on the same day, respectively, which were higher levels than those in Group A.
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PMID:Variations in warfarin concentration in blood and coagulant factors after artificial valve replacement. 147 22

This study was designed to assess whether factors other than high haemoglobin, thrombocytosis and abnormal platelet function predispose to thrombosis in polycythaemia rubra vera (PRV). Components of the fibrinolytic system and concentrations of the naturally occurring anticoagulants were measured in patients and controls in the resting state; the fibrinolytic capacity was reassessed after venous occlusion. The results were related to presence or absence of a history of thromboembolism. Under resting conditions, patients with PRV had reduced plasminogen activator inhibitor antigen levels and higher fibrin plate lysis area and tissue plasminogen activator activity. Protein C, protein S and factor V levels were reduced. Those patients with a history of thromboembolism had decreased tissue plasminogen activator activity after venous occlusion compared to those who had not experienced a thrombosis. We conclude that reduced fibrinolytic capacity may predispose to thrombosis in PRV. Despite treatment to normalize haemoglobin levels, the patients have persistent activation of their fibrinolytic systems. This, and reduced levels of proteins C and S, may be secondary to a chronic, clinically occult, disseminated intravascular coagulation.
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PMID:The fibrinolytic system and proteins C and S in treated polycythaemia rubra vera. 148 3

Methylococcus capsulatus (Bath) uses a soluble methane monooxygenase (sMMO) to catalyse the oxidation of methane to methanol. sMMO is comprised of three components; A, B and C. Protein C (the reductase) transfers electrons from NADH to protein A (the hydroxylase) which contains the active site, and protein B regulates this electron flow. The five genes encoding the sMMO proteins and their subunits are clustered and have been cloned in Escherichia coli. A DNA fragment containing mmoB, the gene encoding protein B, was subcloned into pT7-5, a plasmid of the T7 RNA polymerase promoter expression system. Upon induction, E. coli expressed protein B which was fully functional after purification. The gene encoding protein C, mmoC, was amplified with unique restriction sites at each end using the polymerase chain reaction and then subcloned into pT7-7 (a plasmid similar to pT7-5 but containing its own ribosome-binding site and ATG start codon). Protein C expressed in E. coli was also found to be functional. This is the first report of the functional expression of methanotroph methane monooxygenase genes in a heterologous host and represents a significant step forward in our analysis of the assembly and catalysis of sMMO.
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PMID:Functional expression in Escherichia coli of proteins B and C from soluble methane monooxygenase of Methylococcus capsulatus (Bath). 151 60

Protein C, which is an important anti-thrombotic factor in the blood coagulation cascade, undergoes several post-translational modifications. gamma-Carboxylation on nine glutamic acid residues at the N-terminal region of the light chain [gamma-carboxylated glutamic acid (Gla) domain] is considered to be critical for full anti-clotting activity. It is also known that when recombinant protein C is expressed in animal cells this particular modification is often lost. We were successful in preparing a monoclonal antibody (PC01) which distinguishes the sufficiently gamma-carboxylated protein from the rest by its specific affinity for the Ca(2+)-induced conformational change of the former, and thereby developed a simple process of purifying sufficiently gamma-carboxylated protein C. Culture supernatant of Chinese hamster ovary cell transformants was first applied to Q-Sepharose and recombinant protein C was partially purified. It was then loaded onto a PC01 affinity column in the presence of 5 mM calcium chloride. Sufficiently gamma-carboxylated protein C was retained while insufficient-carboxylated protein C quickly passed through. The former was eluted with 5 mM EDTA efficiently and with high purity, contained eight Gla units per molecule, and had similar anti-clotting activity. The flow-through was relatively impure protein C which contained five Gla units per molecule and showed limited anti-clotting activity. We extended the application of the Ca(2+)-induced conformational change to conventional ion-exchange chromatography. The sufficiently gamma-carboxylated protein C was found to elute earlier in the salt gradient from an anion-exchange column in the presence of 5 mM calcium chloride being fully separated from the insufficiently carboxylated protein C.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification of sufficiently gamma-carboxylated recombinant protein C and its derivatives. Calcium-dependent affinity shift in immunoaffinity and ion-exchange chromatography. 151 29

1. Treatment according to the ALL/NHL-BFM 90 protocol I (induction phase) caused multiple and severe coagulation changes in all 14 patients of our study. Glucocorticoids alone made Fibrinogen drop to 148 mg/dl, AT III and Protein C rise to 136% or even 179% respectively. After day 12, immediately following the start of therapy with Coli-Asparaginase (ASP), fibrinogen continued to drop to reach its lowest average value of 46 mg/dl on day 24. Anticoagulant factors like plasminogen (lowest average value: 36%), AT III (47%) and Protein C (93%) dropped abruptly. These alterations were reversed after discontinuation of Glucocorticoids and ASP. During consolidation (protocol II) similar alterations are observed as in protocol I when Glucocorticoids are applied alone. However, after Erwinia-ASP there is no fall in AT III, plasminogen, and Protein C as is observed in protocol I with Coli-ASP. 2. Severe hemorrhages or thromboses are uncommon as compared to the degree of coagulation changes which can be regularly observed. Complications occur more often in girls. Most of them are seen during the 2nd or 3rd week of simultaneous ASP-Glucocorticoid therapy. 3. To avoid twofold alteration of hemostasis it should be considered to apply Glucocorticoids and ASP separately and to replace Coli-ASP by Erwinia-ASP. The efficacy of prophylactic replacement of decreased coagulation factors has not yet been confirmed. Immunologic and infectious side effects have to be taken into consideration. 4. More definite recommendations can be given when each suspected bleeding and/or thrombosis is confirmed by imaging procedures, when it is documented and registered, and when coagulation studies are performed during the critical phase.
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PMID:[Changes in blood coagulation in treatment with ALL-BFM-90 and NHL-BFM-90 protocols]. 151 63


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