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:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The optimal approach to management of patients after thrombolytic therapy for acute myocardial infarction (AMI) is unclear. The role of anticoagulation with heparin was evaluated in 75 consecutive patients who received intravenous streptokinase for AMI. Heparin therapy was titrated to keep the partial thromboplastin time (PTT) between 90 and 120 seconds. Seventeen episodes of definite myocardial ischemia (associated with reversible electrocardiographic changes) were observed in 13 patients. When episodes of probable myocardial ischemia are included (typical chest pain relieved by nitroglycerin or associated with more than a 15-mm Hg change in blood pressure but without electrocardiographic changes), 52 episodes occurred in 28 patients. Four episodes of definite and 4 of probable myocardial ischemia occurred within 24 hours of discontinuation of heparin. Analysis of the level of anticoagulation as assessed by PTT at the time of the ischemic events shows that ischemia occurred more often at lower PTTs. Nine hemorrhagic complications occurred, all within 24 hours of streptokinase infusion. In 4 patients bleeding was believed to be major and heparin administration was discontinued; 2 patients with gastrointestinal bleeding required blood transfusions. Our data suggest that after thrombolytic therapy for AMI, the level of anticoagulation is inversely related to the frequency of recurrent ischemic events; that discontinuation of heparin is frequently associated with ischemia; and that administration of heparin is associated with a low incidence of hemorrhagic complications.
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PMID:Role of heparin after intravenous thrombolytic therapy for acute myocardial infarction. 381 72

Hageman factor, a coagulation factor (Factor 12) is reported to be deficient in users of OCs (oral contraceptives) in this letter to the editor. A 21-year-old female on OCs for 4 months was admitted with sudden onset of chest pain and shortness of breath; a lung scan confirmed bilateral pulmonary embolism. She underwent a coagulation screen, prior to heparin therapy, which revealed a partial thromboplastin time of 120 seconds. A 15% Hageman factor deficiency was found. It is suggested that before prescribing OCs, physicians should screen patients by partial thromboplastin time, at the least, to determine if Hageman factor is deficient.
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PMID:Hageman factor deficiency and oral contraceptives. 610 95

Platelets have been implicated in the pathogenesis of coronary artery disease, and a number of studies have examined platelet function and coagulation parameters in such patients. We have examined platelet coagulant activities, volumes, and aggregate ratios in 23 patients with chest pain, seven of whom had normal coronary angiograms (group I) and 16 of whom had angiographically proven coronary artery disease (group II). There were no significant differences in the mean values for platelet volume or platelet aggregate ratios between the two groups. The platelet coagulant activities concerned with initiation and the early stages of intrinsic coagulation were significantly increased in patients in group II as compared with those in group I. No significant differences were noted between the two groups with respect to prothrombin time, partial thromboplastin time, and plasma levels of fibrinogen and coagulation factors V and VIII. However, the mean activity in plasma of antithrombin III (but not the level of antithrombin III antigen) was significantly lower in patients of group II compared with group I. Overall, our observations provide evidence for an enhanced contribution of platelets to the intrinsic coagulation system in patients with coronary artery disease. The platelet coagulant hyperactivity noted in these patients may reflect a role of platelets in the pathogenesis of coronary artery disease or may be secondary to the underlying arterial disease.
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PMID:Coagulant activities of platelets in coronary artery disease. 668 40

Although coronary thrombosis is thought to play a pivotal role in the pathogenesis of unstable angina and non-Q wave myocardial infarction and antithrombotic therapy is a mainstay in the early management of these patients, the relation between measures of systemic anticoagulation and clinical events has not been defined clearly. In the Thrombolysis in Myocardial Ischemia III trial, 1473 patients with ischemic chest pain at rest evaluated within 24 hours of symptom onset were randomized to (1) tissue plasminogen activator (TPA) or placebo and (2) an early invasive or an early conservative strategy. All patients received a full complement of anti-ischemic medication, aspirin, and continuous intravenous heparin titrated to an activated partial thromboplastin time (aPTT) of 1.5 to 2.0 times control for 72 to 96 hours. The median aPTT in all study groups exceeded the minimum threshold (45 seconds) by 24 hours and remained within the designated range during the protocol-directed heparin infusion. No differences in median aPTT values for the 72- to 96-hour study period were observed between groups (p=not significant). Median 12-hour heparin concentrations were >0.2 U/ml in all groups; however, values <0.2 U/ml were common thereafter, particularly in TPA-treated patients. Time-dependent covariate analyses failed to identify statistically significant differences in either aPTT or heparin levels between patients with in-hospital clinical events (spontaneous ischemia, myocardial infarction, or death) and those without events (p=0.27). Furthermore, early clinical events occurred in a similar percentage of patients with optimal anticoagulation (all aPTTs >60 seconds, all heparin levels>0.2 U/ml), and those with aPTTs or heparin levels below these thresholds. Aggressive (high-intensity) anticoagulation with heparin to achieve aPTTs >2.0 times control does not appear to offer additional clinical benefit to lower levels (1.5 to 2.0 times control) among patients with unstable angina and non-Q wave myocardial infarction receiving intravenous heparin and oral aspirin. Therefore, the optimal level of anticoagulation in this common clinical setting is between 45 and 60 seconds when heparin is included in the treatment strategy. Direct plasma heparin measurement does not offer an advantage to routine aPTT monitoring. The occurrence of spontaneous ischemia, myocardial infarction, and death in spite of antischemic therapy and optimal anticoagulation (as it is currently defined) with heparin supports ongoing efforts to develop more effective antithrombotic agents.
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PMID:Relation between systemic anticoagulation as determined by activated partial thromboplastin time and heparin measurements and in-hospital clinical events in unstable angina and non-Q wave myocardiaL infarction. Thrombolysis in Myocardial Ischemia III B Investigators. 860 20

A 20 year old man with severe chest pain was hospitalised for acute myocardial infarction. Coronary angiography revealed total obstruction of his right coronary artery, which was successfully recanalised by direct percutaneous transluminal coronary angioplasty (PTCA). There was also diffuse thrombi in the left coronary artery that was not recanalised by perfusion with 3000 U pro-urokinase. Anticoagulant therapy was performed after PTCA. Creatine kinase peaked one day after hospitalisation (4805 U/l). The activated partial thromboplastin time was 62.6 seconds (45%). Plasma anticardiolipin IgG antibodies were high (3.8 and 2.7) in repeated examinations. The PTCA site was patent after three months. Primary antiphospholipid syndrome should be considered as a cause of acute myocardial infarction in young adults, and PTCA with anticoagulant treatment is effective for initial treatment of the syndrome.
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PMID:Primary antiphospholipid syndrome with acute myocardial infarction recanalised by PTCA. 950 29

Background: Myocardial ischemia at rest is typically associated with atherosclerotic coronary artery disease, atherommous plaque rupture, and intracoronary thrombosis. In areas of advanced disease and vascular injury, the extent of thrombus is influenced largely by a delicate balance of procoagulant factors, favoring thrombus initiation, growth, and development, and anticoagulant factors, attempting to limit potentially flow-limiting coronary thrombosis. Thrombin, a 308 amino acid serine pretense, is considered the most patent procoagulant factor in the setting of acute vessel wall injury, playing an essential role in the conversion of fibrinogen to fibrin, accelerating the prothrombinase complex, activating platelets, and stabilizing fibrin polymers. The purpose of this study was to determine the relationship between electrocardiographic abnormalities and markers of thrombin activity and generation among patients with unstable angina and non-Q.wave myocardial infarction. Mehtods and Results: In a study of 36 patients (59.1+/- 11.0 years) with myocardial ischemia at rest participating in the Thrombolysis in Myocardial Ischemia (TIMI) IIIB trial, thrombin activity in plasma, as determined by fibrinopeptide A (FPA), prothrombin fragment 1.2 (F 1.2), and thrombin-antithrombin III complexes (TAT) concentrations, were found to be increased significantly when compared with healthy volunteers (p < 0.004). Thrombin generation was also increased modestly compared with age-matched patients with stable coronary artery disease undergoing elective cardiac catheterization. Given that,he surface 12-lead electrocardiogram (ECG) is frequently abnormal in patients with ischemic chest pain at rest and represents a readily available, first-line diagnostic test for assessing disease activity and treatment response, we investigated whether ECG abnormalities and thrombin activity/generation in plasma were correlated. Twenty-six patients (72%) had ECG changes compatible with myocardial ischemia at the time of study entry, including 18 (50%) with newly inverted T waves (or pseudonormalization), 14 (39%) with reversible ST-segment depression, and 4 (11%) with transient (<30 minutes) ST-segment elevation. Within the predefined ECG groups there were no differences in plasma thrombin activity between patients with and those without confirmed abnormalities. Similarly, there were no differences in either plasma thrombin activity or generation between the predefined ECG groups. Conclusion: Although ECG abnormalities supporting the presence of myocardial ischemia occur commonly in patients with chest pain at rest, they do not correlate closely with markers of thrombin activity and generation in plasma. The diagnostic and prognostic capabilities of these diagnostic tools, considered either alone or together, require further investigation.
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PMID:Surface 12-Lead Electrocardiographic Findings and Plasma Markers of Thrombin Activity and Generation in Patients with Myocardial Ischemia at Rest. 1060 19

Intracoronary thrombosis is fundamental to the pathogenesis of acute myocardial infarction (MI), yet few studies have examined the diagnostic value of routine coagulability markers, such as the activated partial thromboplastin time (aPTT), in patients with chest pain. We hypothesized that the initiation of thrombosis early in MI would shorten the aPTT, and conducted a retrospective cohort study of patients admitted with a diagnosis of chest pain through the emergency department of one community hospital between 1 January and 30 August 1998. Patients were diagnosed as MI positive or negative based on World Health Organization (WHO) criteria. The aPTT obtained on arrival (prior to anticoagulation therapy) was retrieved from the electronic medical record. Of 120 eligible patients (49% female, mean age 63.7 years), 27 (23%) were diagnosed with MI. Patients with an aPTT <or= control (n = 73, 61%) were significantly more likely to be diagnosed with MI than those with an aPTT > control (RR = 2.83, 95% confidence interval 1.15 to 6.96, P = 0.013). A shortened aPTT (<or= control) on presentation in patients with chest pain is associated with increased risk of acute MI. This information is available before other serum markers of MI, and may facilitate early treatment decisions. Further study is warranted.
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PMID:The activated partial thromboplastin time in early diagnosis of myocardial infarction. 1155 4

The present study was designed to determine the maximum tolerated dose (MTD), toxicity profile, pharmacokinetics (PKs), and antitumor activity of the protein kinase C-alpha antisense oligonucleotide ISIS 3521 (ISIS Pharmaceuticals, Inc., Carlsbad, CA) when administered in combination with 5-fluorouracil (5-FU) and leucovorin (LV). Patients with refractory solid tumors received ISIS 3521 as a 21-day continuous infusion administered simultaneously with 5-FU and LV given daily for 5 days repeated every 4-5 weeks (one cycle). 5-FU and ISIS 3521 PK analysis were performed on samples taken during the first cycle in all patients. Fifteen patients received ISIS 3521 at one of three dose levels: (a) 1.0 (n = 3 patients); (b) 1.5 (n = 3 patients); and (c) 2.0 (n = 9 patients) mg/kg/day. All patients simultaneously received 5-FU (425 mg/m(2)/day) and LV (20 mg/m(2)/day) for 5 consecutive days. Grade 1-2 toxicities included alopecia, fatigue, mucositis, diarrhea, anorexia, nausea/vomiting, and tumor pain. One patient had grade 3 chest pain considered to be related to 5-FU therapy, another patient had dose-limiting grade 3 mucositis resolving in <7 days, and one patient with a history of gastritis had an acute upper gastrointestinal bleed thought to be 5-FU-induced toxicity. Five patients developed cycle 1 grade 4 neutropenia, which resolved without colony-stimulating factors before the next treatment cycle. There were no effects on prothrombin time and activated partial thromboplastin time. A clinically defined MTD was not reached. The character and severity of these toxicities do not seem to be dose related, and, as such, there was no classical dose-limiting toxicity defining the MTD. ISIS 3521 PKs in the presence of 5-FU was consistent with those reported previously. 5-FU PK parameters were also similar in the presence or absence of ISIS 3521. Six of 14 patients ( approximately 43%) across all dose cohorts had an improvement in measurable tumor response ranging from minor reduction in tumor size (4 patients) to objective partial response (>50% reduction in tumor size, 2 patients). ISIS 3521 is tolerable at its recommended single-agent dose when given with 5-FU and LV. There is no apparent PK interaction between ISIS 3521 and 5-FU and LV. Antitumor activity was observed with the combination; however, it is uncertain whether clinical activity is a result of enhanced drug interaction. Our study warrants further exploration of efficacy in a Phase II and/or Phase III clinical trial setting.
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PMID:Phase I clinical and pharmacokinetic study of protein kinase C-alpha antisense oligonucleotide ISIS 3521 administered in combination with 5-fluorouracil and leucovorin in patients with advanced cancer. 1194 11

Increased platelet activation is well documented in patients with acute coronary syndromes and can be detected by various methods, including flow cytometry and enzyme-linked immunosorbent assay. However, such techniques require several steps and cannot provide quick results. Platelet activation ultimately results in procoagulant phospholipid exposure and we have previously described a simple activated factor X-activated clotting time (XACT) test that is insensitive to resting platelets but that is significantly shortened by activated platelets, microparticles and procoagulant phospholipids. Our aim was to determine whether the XACT test could be used to distinguish patients with chest pain due to cardiac ischaemia from those having chest pain due to non-cardiac causes. We thus carried out XACT tests on ethylenediamine tetraacetic acid whole blood and plasma samples obtained from 46 patients presenting to the emergency department with chest pain and from 30 controls. Sixteen cases (30%) were subsequently diagnosed as acute coronary syndromes. Blood samples from these patients displayed overall significantly shortened XACT results relative to both healthy controls (P<0.001) and chest pain not due to cardiac ischaemia (P<0.004). This discrimination was much better with whole blood samples than when platelet-poor plasmas were tested (P=0.153), suggesting that free microparticles were not the only factors responsible. Thus, the detection of increased procoagulant phospholipid activity in whole blood by shortened XACT results may be a simple and rapid diagnostic marker of some cardiac ischaemic events.
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PMID:Increased procoagulant phospholipid activity in blood from patients with suspected acute coronary syndromes: a pilot study. 1597 Jul 23

A 21-year-old man was admitted to our hospital because of leg edema. Because laboratory findings revealed massive proteinuria and hypoproteinemia, he was diagnosed as having nephritic syndrome caused by minimal change disease. He was given a continuous heparin infusion and intravenous steroid therapy, at a prednisolone dose of 1 mg/kg per day, and his condition gradually improved. Five months after discharge, the patient's proteinuria relapsed. He was readmitted to our hospital and we restarted anticoagulant treatment with intravenous heparin and 60 mg prednisolone. On the third hospital day, he complained of chest pain with sudden onset and dyspnea. He quickly developed shock and died. The findings of an autopsy confirmed the presence of diffuse fibrin thrombi in bilateral pulmonary arteries, and we diagnosed the cause of death as diffuse pulmonary artery thrombosis. A coagulation test for activated partial thromboplastin time (aPTT) had already shown that aPTT was prolonged before the initiation of treatment. There may have been a deficit of antithrombin III (ATIII) - a cofactor of heparin - because of the proteinuria; thus, the continuous heparin treatment might not have been effective for the prevention of thrombosis. Alternatives to heparin treatment that do not suppress AT III, such as nafamostat mesilate or argatroban, which do not require the presence of AT III for their anticoagulant action, should be considered in cases similar to the that in the patient reported here. In patients with nephrotic syndrome who exhibit altered coagulation test results, the choice of anticoagulation therapy for treatment of the hypercoagulabilty status associated with nephrotic syndrome should be carefully considered.
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PMID:Fatal diffuse pulmonary arterial thrombosis as a complication of nephrotic syndrome. 1808 94


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