Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Livedoid vasculitis, a hyalinizing vasculopathy, is characterized by extensive formation of microthrombi and deposition of fibrin in the middermal vessels, which result in epidermal infarction, ulceration, and formation of stellate scars. In a prospective study of nonhealing ulcers in patients with livedoid vasculitis, we found a high incidence of anticardiolipin antibodies, lupus anticoagulants, increased levels of plasminogen activator inhibitor, and low levels of endogenous tissue plasminogen activator (t-PA) activity. This procoagulant tendency and decreased fibrinolysis may provide an explanation for the occlusive vasculopathy often noted in biopsy specimens from these patients. On the basis of these findings, we proposed that fibrinolysis with recombinant t-PA would lyse microvascular thrombi, restore circulation, and promote wound healing. In six patients who had nonhealing ulcers caused by livedoid vasculitis and in whom numerous conventional therapies had failed, low-dose t-PA (10 mg) was administered intravenously during a 4-hour period daily for 14 days. Five of the six patients had dramatic improvement; almost complete healing of the ulcers occurred during hospitalization, and tissue oxygenation, as measured by transcutaneous oximetry, increased. The one treatment failure was due to rethrombosis of the microvasculature; this patient was subsequently re-treated but with concurrent anticoagulation, and her leg ulcers healed. We conclude that daily administration of a low dose of t-PA is safe and effective treatment for nonhealing ulcers due to occlusive vasculopathy.
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PMID:Tissue plasminogen activator for treatment of livedoid vasculitis. 143 47

A major adverse effect of recombinant human erythropoietin (r-HuEPO) in hemodialyzed patients are thrombotic events. Several reports on platelet function during r-HuEPO treatment have been published but less is known about fibrinolysis. In the present study, the fibrinolytic capacity was studied in 20 patients on maintenance hemodialysis and treated with r-HuEPO. The patients were randomized into two groups and investigated in a crossover design. r-HuEPO was administered intravenously and subcutaneously in each group and was given for 3 months, respectively. Plasma tissue plasminogen activator (t-PA) and released t-PA remained unaffected by r-HuEPO in both groups throughout the study. Tissue plasminogen activator inhibitor (PAI) increased in a cyclic way reaching peak values 4-6 weeks after the start of investigation and again 4-6 weeks after changing therapy. The increase in PAI was significant in the two groups (0.025 > p > 0.01). Tissue plasminogen antigen was low in the uremic patients. The influence of r-HuEPO on this parameter was not investigated. Compensatory changes in plasma levels of factor XII procoagulant activity, activated protein C and of alpha 2-antiplasmin were not observed. Thrombotic events occurred in 4 patients at peak values of PAI. Six patients required an increase in heparin dose simultaneously with the increase in PAI. Thus, r-HuEPO seemed to affect the fibrinolytic capacity of uremic patients.
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PMID:Fibrinolytic capacity in hemodialysis patients treated with recombinant human erythropoietin. 143 39

Secretion of plasminogen activators and their inhibitors was examined in cultures of human retinal pigment epithelial (RPE) cells. The methods employed were zymography and reverse zymography, solid-phase immunocapture assay, metabolic labeling followed by immunoprecipitation, and immunofluorescence. The results showed that these cells produce urokinase-type plasminogen activator (u-PA) and a plasminogen activator inhibitor (PAI) which is immunologically and biochemically similar to PAI-1. Tissue-type plasminogen activator activity (t-PA) was not detected, but we detected small amounts of t-PA in an inactive complex with inhibitor in RPE cell-conditioned media. We conclude that RPE cells have the potential to utilize u-PA-catalyzed plasminogen activation which is subject to regulation by PAI-1. These results may have a bearing on the pathogenesis of proliferative retinal diseases.
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PMID:Retinal pigment epithelial cells secrete urokinase-type plasminogen activator and its inhibitor PAI-1. 143 81

In order to study the effects of chronic venous hypertension due to heart failure on blood fibrinolytic activity, tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor 1 (PAI-1) antigen, t-PA activity and PAI activity were measured before and after venous occlusion of the arm for 20 min in 15 patients with right-sided heart failure, 15 patients with left-sided heart failure, and 30 control healthy subjects. Central venous pressure, measured by observing the jugular veins, was above 15 cm of the blood column in all patients with right-sided heart failure, and normal (below 8 cm) in all patients with left-sided heart failure and control subjects. There was no difference in the basal concentrations of t-PA (11.0, 10.2 and 10.8 ng/ml; all values medians) and PAI-1 antigens and their activities between right and left-sided heart failure and the control subjects. After the occlusion, t-PA antigen increased significantly less in right-sided heart failure (28.6 ng/ml) than in left-sided heart failure and the control subjects (54.5 and 45.9 ng/ml, respectively). It was concluded that the poor increase in fibrinolytic activity that had already been reported in patients with heart failure, was due to low t-PA release during occlusion and not to a high basal PAI level. It was limited to the patients with right-sided heart failure and was probably the consequence of chronic systemic venous hypertension.
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PMID:Tissue plasminogen activator release in chronic venous hypertension due to heart failure. 144 Apr 98

The fibrinolytic system was studied in 96 patients with type I diabetes mellitus. Patients were grouped according to their degree of retinopathy; 38 patients with no evidence of retinopathy, 28 patients with background retinopathy and 30 patients with proliferative retinopathy. Thirty healthy individuals served as controls. The basal fibrinolytic activity as measured by clot lysis time and t-PA activity was increased in diabetic patients. This was associated with low levels of plasminogen activator inhibitor. Increased levels of D-dimer in diabetic patients further indicate enhanced in vivo fibrinolysis. The increase in fibrinolytic activity was highest in diabetics without retinopathy, and decreased with increasing retinopathy. Endothelial release of t-PA after venous occlusion was not different between controls and all diabetic groups. These findings suggest that in type I diabetics the fibrinolytic system is in an activated state. With worsening of retinopathy this increase in fibrinolytic activity diminishes.
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PMID:Enhancement of spontaneous fibrinolytic activity in diabetic retinopathy. 144 70

Although a considerable number of publications on tissue plasminogen activator (t-PA) in human milk have appeared, most investigators have determined t-PA activity using an assay on fibrin plates [1, 2, 3, 4]. We measured t-PA activity by a bioimmunoassay and t-PA antigen by ELISA using a monoclonal antibody (SP-322) [6], and estimated t-PA index ((t-PA activity, ng/ml)/(t-PA antigen, ng/ml) x 100) in human colostrum and milk to evaluate the fluctuations of post-delivery t-PA. The concentrations of t-PA activity decreased slowly related to the duration of lactation varying between days one and two hundred and ten and showed significant negative correlation with the duration (P less than 0.001). The t-PA antigen made a slow descent, followed by a reciprocal ascent of the t-PA index to the fifty eighth post-delivery day and showed significant correlations with the duration (P less than 0.001, P less than 0.05, respectively). This information suggests that a high concentration of t-PA may be released into the narrow channels of the glands functioning to maintain duct patency under the regulation of an inhibitor such as plasminogen activator inhibitor (PAI).
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PMID:Determination of t-PA activity and t-PA antigen in human milk. 145 94

Rat ovarian cells produce not only plasminogen activator (tPA) but also plasminogen activator inhibitor type 1 (PAI-1), and their coordinated geneexpression induced by gonadotropins are thought to be responsible for follicular rupture. In this study, it was demonstrated that (1) theca-interstitial compartment synthesizes the majority of PAI-1 activity in the ovary before ovulation, the follicular wall may therefore serve as a specific barrier to prevent the secretion of PA into the extrafollicular compartment; (2) Granulosa cells contribute only small amount of ovarian PAI-1 activity, but synthesize most of tissue-type plasminogen activator activity involved in the process leading to ovulation: (3) Since only matured cumulus-oocyte complexes secrete high level of tPA and PAI-1, both tPA and PAI-1 activity in the conditioned medium may be used as reliable markers for evaluating oocyte quality for in vitro fertilization.
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PMID:[Hormonal regulation of PAI-1 secretion by cultured rat ovarian cells]. 145 60

A new assay for functional plasminogen activator inhibitor 1 (PAI-1) in plasma was developed. The assay is based on the quantitative conversion of PAI-1 to urokinase-type plasminogen activator (u-PA)-PAI-1 complex the concentration of which is then determined by an ELISA employing monoclonal anti-PAI-1 as catching antibody and monoclonal anti-u-PA as detecting antibody. The assay exhibits high sensitivity, specificity, accuracy, and precision. The level of functional PAI-1, tissue-type plasminogen activator (t-PA) activity and t-PA-PAI-1 complex was measured in normal subjects and in patients with venous thromboembolism in a silent phase. Blood collection procedures and calibration of the respective assays were rigorously standardized. It was found that the patients had a decreased fibrinolytic capacity. This could be ascribed to high plasma levels of PAI-1. The release of t-PA during venous occlusion of an arm for 10 min expressed as the increase in t-PA + t-PA-PAI-1 complex exhibited great variation and no significant difference could be demonstrated between the patients with a thrombotic tendency and the normal subjects.
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PMID:A specific immunologic assay for functional plasminogen activator inhibitor 1 in plasma--standardized measurements of the inhibitor and related parameters in patients with venous thromboembolic disease. 145 92

Cyclosporine treatment has been associated with thrombotic vascular complications. We investigated the activity of the fibrinolytic system and its capacity to respond upon DDAVP stimulation in a group of 20 cyclosporine-treated patients as compared with a group of 9 azathioprine-treated patients. Furthermore, the effect of the administration of fish-oil to these patients on the endogenous fibrinolytic activity was studied in a double-blind randomized, placebo-controlled cross-over study. The cyclosporine-treated patients showed a significantly reduced plasminogen activator activity and plasmin generation response upon the infusion of DDAVP as compared with the azathioprine group. In the cyclosporine group 60% of the patients had an impaired fibrinolytic response, whereas this was found in only 11% of the azathioprine-treated patients (P < 0.05). The impairment of the endogenous fibrinolysis activity could be attributed either to a defective release of plasminogen activator from the vessel wall (67% of patients) or to high plasma levels of plasminogen activator inhibitor 1 (33% of patients). Administration of fish-oil resulted in a significant improvement of the impaired fibrinolysis in the cyclosporine group. Particularly, in patients with a defective release of plasminogen activator from the vessel wall, fish-oil treatment resulted in a normalization of the fibrinolytic activity. These results indicate that cyclosporine treatment induces an impaired fibrinolysis that may contribute to the frequent occurrence of thromboembolic complications and eventually the impairment of renal function in cyclosporine-treated patients. The beneficial effect of the administration of fish-oil on the endogenous fibrinolysis may result in a reduction of the adverse events associated with cyclosporine treatment.
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PMID:Impaired fibrinolysis in cyclosporine-treated renal transplant patients. Analysis of the defect and beneficial effect of fish-oil. 146 91

Hemostatic variables are increasingly recognized as atherothrombotic risk markers and their susceptibility to lifestyle changes has therefore considerable interest. To study this subject knowledge of the spontaneous variability of measures of coagulation and fibrinolysis is required. We monitored 17 young male adults with constant lifestyles for a year and here present characteristics of the observed variability of factor VII coagulant activity (F VIIc), fibrinogen, fibrinolytic variables and blood lipids. The variables differed considerably with regard to total variability (range of CV (%): 13-54) and with respect to relative size of the inter- and intrapersonal components of variation. None of the variables showed seasonal changes of biological significance. Descriptive statistics of the same variables measured in 74 young healthy adults (19 women, 55 men) are also reported. These values may be used as a reference for comparable groups of individuals. Serum triglycerides were significantly associated with F VIIc (Spearman's Rs = 0.24, P < 0.05) and plasma concentrations fo the plasminogen activator inhibitor type I (Spearman's RS = 0.23, P = 0.05). An increased thrombotic tendency with elevated triglyceride levels was thus indicated. Serum cholesterol was not associated with hemostatic variables, except for plasminogen activator activity (Spearman's Rs = 0.31, P < 0.05).
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PMID:The variability of and associations between measures of blood coagulation, fibrinolysis and blood lipids. 146 54


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