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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined the effect of age on left ventricular (LV) function, assessed by contrast ventriculography 3 weeks after a first acute myocardial infarction in 312 patients who received thrombolytic therapy within 4 hours of the onset of infarction and in 83 patients who received placebo. Streptokinase was given to 188 patients and recombinant tissue-type plasminogen activator (rt-PA) to 124. Patients were divided into 2 age groups: less than 60 years (n = 244) and greater than or equal to 60 years (n = 151). Thrombolytic therapy improved ejection fraction in both age groups: from 54 +/- 13 to 59 +/- 11% (p = 0.021) in the younger group and from 50 +/- 14 to 57 +/- 13% (p = 0.004) in the older group. Ejection fraction was identical in streptokinase- and rt-PA-treated patients. Multifactor analysis of variance revealed that younger age and thrombolytic therapy were independently associated with improved ejection fraction. Thrombolytic therapy also reduced end-systolic volume (p = 0.001) by 14 ml in the elderly and 9 ml in the younger group. Minor bleeding complications were more frequent in the elderly and 3 serious hemorrhages occurred in patients greater than or equal to 60 years. These findings reveal that thrombolysis improves LV function in all age groups studied. Because increasing age is independently associated with a lower ejection fraction after acute myocardial infarction, thrombolytic therapy may confer greater benefits in older patients.
Am J Cardiol 1991 May 01
PMID:Comparison of effects of thrombolytic therapy on left ventricular function in patients over with those under 60 years of age. 190 54

Infarct size, left ventricular function and infarct-related coronary artery patency were examined in 108 patients who took part in a previously reported placebo-controlled trial of recombinant tissue-type plasminogen activator (rt-PA) in acute myocardial infarction. Coronary angiography was performed 17 +/- 0.8 h after initiation of treatment in 47 patients (group A) or at 10 days in 61 patients (group B). Both groups underwent radionuclide ventriculography 3.8 +/- 0.8 h and again on day 9 after treatment and quantitative thallium scintigraphy on day 8. In group A, the infarct-related artery was patent in 53%; these patients had a smaller global (15.1 +/- 2.5% vs. 25.7 +/- 4.7%, p = 0.029) and regional (14.7 +/- 2.5% vs. 24.1 +/- 4.7%, p = 0.044) fixed thallium defect than did those with an occluded artery. Infarct regional ejection fraction improved by 10.1 +/- 2.1% between early and late studies when the infarct-related artery was patent and by 4.8 +/- 1.4% if it was occluded (p = 0.048); changes in global and noninfarct regional ejection fraction were similar irrespective of perfusion status. Infarct regional ejection fraction and fixed thallium defect were inversely related only when the infarct-related artery was occluded (r = -0.83, p less than 0.0001). In group B, 10 day patency of the infarct-related artery was 67%; there was no difference in patency by treatment assignment or in left ventricular function or infarct size between patients with and without infarct-related artery patency. There was no evidence of an effect of rt-PA therapy beyond that expressed through coronary patency alone in either group A or group B.
J Am Coll Cardiol 1991 Jun
PMID:Coronary patency, infarct size and left ventricular function after thrombolytic therapy for acute myocardial infarction: results from the tissue plasminogen activator: Toronto (TPAT) placebo-controlled trial. TPAT Study Group. 190 5

Twenty patients with acute myocardial infarction treated with recombinant tissue-type plasminogen activator (rt-PA) had endogenous factor XII-dependent fibrinolytic activity levels measured throughout the hospital period and those levels were prospectively correlated with the incidence of recurrent myocardial infarction until 8 weeks after hospital discharge. Within the follow-up period, recurrent myocardial infarction was observed in 8 patients, whereas the remaining 12 patients showed no clinical evidence of recurrence. The patients in the reinfarction group were characterized by a more pronounced depletion of and sustained lower levels of factor XII-dependent fibrinolytic activity than were the patients with no reinfarction (p less than 0.05). The decrease in fibrinolytic activity during rt-PA therapy was significantly associated with a depletion of functional alpha 2-antiplasmin, the primary plasmin inhibitor. These results indicate that, paradoxically, coronary thrombolysis with rt-PA involves depletion of endogenous factor XII-dependent fibrinolytic activity levels, which constitutes a risk for early myocardial reinfarction.
J Am Coll Cardiol 1991 Aug
PMID:Depression of factor XII-dependent fibrinolytic activity characterizes patients with early myocardial reinfarction after recombinant tissue-type plasminogen activator therapy. 190 4

Recent studies of interventional therapy by way of the coronary venous system have demonstrated that it can protect acutely ischemic myocardium. To evaluate the efficacy of coronary venous retroinfusion compared with systemic intravenous administration of recombinant tissue-type plasminogen activator (rt-PA), 14 dogs were studied with a copper coil-induced thrombus in the left anterior descending coronary artery. The rt-PA (24,000 fluorescence units/kg) was administered continuously, either intravenously (n = 8) or retrogradely (n = 6), for 30 min beginning 60 min after coronary occlusion. Thrombolysis was determined by repetitive coronary angiography. All dogs were killed 3 h after termination of rt-PA infusion and infarct size was measured by the triphenyltetrazolium chloride staining technique. Complete thrombolysis occurred in five of the six dogs in the retroinfusion group and four of the eight dogs in the systemic intravenous infusion group. Partial lysis was achieved in two dogs treated by intravenous infusion. Lysis did not occur in one dog treated with retroinfusion and in two dogs treated with intravenous infusion. Time to thrombolysis was 13.4 +/- 2.3 min in the retroinfusion group versus 27.8 +/- 4.8 min in the intravenous group (p less than 0.001). Myocardial functional recovery in the ischemic zone measured by two-dimensional echocardiography 60 min after reperfusion was significant only in the retroinfusion group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
J Am Coll Cardiol 1991 Aug
PMID:Retrograde coronary venous administration of recombinant tissue-type plasminogen activator: a unique and effective approach to coronary artery thrombolysis. 190 6

Potentially life-threatening immediate hypersensitivity reactions are extremely rare among patients treated with thrombolytic agents for suspected acute myocardial infarction. A patient who developed a severe reaction during an infusion of recombinant tissue-type plasminogen activator is described. Potential causal mechanisms for the reaction could be related either to nonmedicinal additives or complement activation. Implications for treatment in the setting of acute myocardial infarction are discussed.
Can J Cardiol 1991 Sep
PMID:Anaphylactoid reaction during an infusion of recombinant tissue-type plasminogen activator for acute myocardial infarction. 193 36

Both activation of platelets and elevation of plasminogen activator inhibitor type 1 (PAI-1) activity in plasma have been associated with acute myocardial infarction. Growth factors from platelet alpha-granules have been shown to increase PAI-1 synthesis in liver and endothelial cells in culture. The present study was designed to determine whether activation of platelets in vivo increases PAI-1 activity in plasma, thereby potentially attenuating thrombolysis. Carotid arteries in rabbits were stimulated with transluminal anodal current to initiate thrombosis manifested initially by cyclic flow variations known to reflect platelet activation. Flow was monitored with Doppler flow probes. Plasma PAI-1 activity (mean +/- SEM) assayed spectrophotometrically increased from 6.8 +/- 0.8 arbitrary units (AU)/ml to a peak of 19.1 +/- 2.9 AU/ml (n = 15) 4.8 +/- 0.6 h after the onset of cyclic flow variations. The magnitude of peak PAI-1 values correlated closely with the frequency and duration of antecedent cyclic flow variations. Complete thrombotic occlusion did not elevate PAI-1 beyond that seen with severe, repetitive partial occlusions (18.7 +/- 4.6 vs. 19.6 +/- 3.8 AU/ml). However, when recanalization of completely occluded vessels was induced with tissue-type plasminogen activator (t-PA), plasma PAI-1 increased more markedly (from 5.6 +/- 0.7 to 112.8 +/- 22.3 AU/ml, n = 11), exceeding the increase after corresponding intervals in animals in which t-PA failed to induce recanalization (from 5.2 +/- 1.1 to 28.3 +/- 6.1 AU/ml, n = 6). Thus, activation of platelets accompanying thrombosis or thrombolysis, or both, markedly increases PAI-1 activity in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
J Am Coll Cardiol 1991 Nov 15
PMID:Augmentation of plasminogen activator inhibitor type 1 activity in plasma by thrombosis and by thrombolysis. 193 60

The (Thrombolysis in Myocardial Infarction) TIMI-I trial led to the hypothesis that the greater reperfusion rate seen with recombinant tissue-type plasminogen activator (rt-PA) versus streptokinase would result in greater reductions in infarct size and mortality in patients with acute myocardial infarction. Despite extensive investigation, no trial comparing rt-PA with streptokinase (European Cooperative Study Group, Plasminogen Activator Italian Multicenter Study [PAIMS], Gruppo Italiano per lo Studio della Sopravvivenze nell'Infarto Miocardico [GISSI-2], International Study on Infarct Survival [ISIS-3], even TIMI-I itself) nor rt-PA and anisoylated plasminogen-streptokinase activator complex (APSAC or anistreplase) (Bassand, TEAM-3, ISIS-3), have confirmed this hypothesis. In a reversal of traditional scientific method, the studies, rather than the unconfirmed hypothesis, have been rejected. A lack of independent review of this subject may have contributed to this outcome. It is proposed that standards of review and editorial comment mandating true critical distance and independence be followed, permitting greater independence of scientific inquiry, review and debate.
J Am Coll Cardiol 1991 Nov 15
PMID:Thrombolysis: the need for a critical review. 193 63

The incidence of myocardial infarction and sudden cardiac death is highest in the morning. Inhibition of fibrinolytic activity in blood also peaks in the morning and this inhibition may favor the development of arterial thrombosis. It has been reported that patients treated with beta blockers do not show the typical circadian pattern of onset of myocardial infarction and sudden cardiac death. This study was undertaken to investigate whether beta blockade alters the circadian rhythm of 2 major fibrinolytic factors, tissue-plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1). Repeated blood samples were taken over a 24-hour period in 13 healthy volunteers: 7 taking 160 mg/day of long-acting propranolol orally for 14 days, and the other 6 taking no medications. Blood samples were analyzed for the plasma levels of t-PA activity, t-PA antigen, PAI activity and PAI-1 antigen. A significant circadian variation of all 4 parameters was present in both groups. No significant differences in peak and nadir values, 24-hour mean, amplitude of fluctuation, and time of peak and nadir were found between the treated and untreated subjects. The data therefore suggest that propranolol treatment does not affect the plasma concentrations at rest or the endogenous circadian rhythm of t-PA and PAI-1 in healthy volunteers. The reported alteration in the circadian pattern of onset of myocardial infarction and sudden cardiac death by beta blockers does not appear to be mediated by effects on the fibrinolytic system.
Am J Cardiol 1991 Nov 15
PMID:Effect of propranolol (long-acting) on the circadian fluctuation of tissue-plasminogen activator and plasminogen activator inhibitor-1. 195 Nov 15

This study sought to determine whether clinical variables can be used to identify patients at high risk of recurrent spontaneous myocardial ischemia or hemodynamic compromise during the 1st 4 days after intravenous thrombolysis for acute myocardial infarction. Of 288 patients randomly assigned to a conservative postthrombolysis strategy, 54 (19%) required urgent cardiac catheterization within 24 h; 75 (26%) underwent urgent cardiac catheterization within 4 days of admission. Of the clinical variables examined by multiple logistic regression analysis, only patient age and anterior wall myocardial infarction correlated with the need for urgent cardiac catheterization (p = 0.0016 and p = 0.017, respectively). Compared with recombinant tissue-type plasminogen activator or urokinase monotherapy, combination therapy with these agents was associated with a lower need for acute intervention during the 1st 24 h after admission, but the difference did not reach statistical significance (14% for combination therapy vs. 21% for each agent alone, p = 0.30). Of the 75 patients undergoing urgent coronary angiography, only 39% had an occluded infarct-related artery. Emergency coronary angioplasty was performed in 49% of the patients and coronary artery bypass graft surgery was performed urgently in 3%. Despite these interventions, the need for urgent cardiac catheterization was associated with an in-hospital mortality rate of 7% (vs. 3% in the group not requiring urgent angiography, p = 0.36); mean left ventricular ejection fraction was 50.5 +/- 11% (vs. 54.3 +/- 10.8%, p = 0.12) and regional infarct zone wall motion was -2.68 +/- 1.07 SD/chord (vs. -2.46 +/- 1.19 SD/chord; p = 0.44).(ABSTRACT TRUNCATED AT 250 WORDS)
J Am Coll Cardiol 1991 Dec
PMID:Determinants of the need for early acute intervention in patients treated conservatively after thrombolytic therapy for acute myocardial infarction. TAMI-5 Study Group. 196 Mar 2

The safety and efficacy of a new regimen of intravenous recombinant tissue-type plasminogen activator (rt-PA) potentially suitable for either pre- or in-hospital administration were assessed in 60 patients with acute myocardial infarction in an open label coronary angiographic study. The regimen consisted of a 20-mg bolus dose followed 30 min later by a delayed infusion of 80 mg over 2 h. This regimen was designed to facilitate prehospital administration of rt-PA. Infarct-related artery patency (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) was observed in 40 of 53 patients at 60 min (75.5%, 95% confidence intervals [CI] 61% to 84%) and in 55 of 60 patients at 90 min (91.7%, 95% CI 80% to 95%) after the rt-PA bolus. By 90 min the majority of patients (55%) exhibited TIMI grade 3 flow; infarct artery patency at 120 min was 84.9%. During hospitalization definite recurrent ischemia occurred in nine patients (15%); nonfatal recurrent infarction was noted in one (1.7%). Four patients (6.7%) experienced major bleeding, including one with intracranial bleeding. There were seven deaths (11.7%). Mortality was significantly influenced by the occurrence of cardiogenic shock, which was present in five patients at the time of enrollment. Blood fibrinogen levels were obtained before and during rt-PA infusion. At baseline and 30 and 150 min after the bolus dose, the mean fibrinogen level (+/- SD) was 284.83 +/- 77.39, 237.96 +/- 76.92 and 192.04 +/- 57.82 mg/dl, respectively. Compared with the baseline value, there was a significant (p less than 0.05) decrease in fibrinogen at both 30 and 150 min.(ABSTRACT TRUNCATED AT 250 WORDS)
J Am Coll Cardiol 1991 Dec
PMID:Safety and efficacy of a new regimen of intravenous recombinant tissue-type plasminogen activator potentially suitable for either prehospital or in-hospital administration. 196 Mar 29


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