Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In five cases of giant hypertrophic gastritis (Menetrier's disease) biopsied gastric mucosa was examined for fibrinolytic activity; in all cases there was marked elevation of the activity due mainly to tissue plasminogen activator. The patients were given antifibrinolytic therapy with oral tranexamic acid (trans-4-aminomethyl cyclohexane carboxylic acid; trans-AMCHA), and four of the patients showed marked improvement of their hypoproteinemia as well as their mucosal disorders. One patient, who showed moderate increase of serum protein level but no reduction of the mucosal disorder, finally received gastrectomy. It was concluded that antifibrinolytic therapy seemed to block the vicious circle of 'membrane disorders', 'increased tissue fibrinolysis', 'increased vascular permeability' and 'hypoproteinemia' in Menetrier's disease.
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PMID:Anti-fibrinolytic therapy of giant hypertrophic gastritis (Menetrier's disease). 36 27

The properties of the cationic locus within the recombinant (r) kringle 2 domain (residues 180-261) of tissue-type plasminogen activator ([K2tPA]) that are responsible for stabilization of its interaction with the carboxylate moiety of omega-amino acid ligands have been assessed by determination of the binding constants of several such ligands to a variety of r-[K2tPA] mutants obtained by oligonucleotide-directed mutagenesis. We have generated, expressed in Escherichia coli, and purified alanyl mutants of individual histidyl,lysyl, and arginyl residues of r-[K2tPA] and determined the dissociation constants of several omega-amino acids, viz., 6-aminohexanoic acid (6-AHxA), 7-aminoheptanoic acid (7-AHpA), L-lysine (L-Lys), and trans-(aminomethyl)cyclohexane-1-carboxylic acid (AMCHA), to each of the r-[K2tPA] variants. We find that K33 plays the most significant role as a cationic partner of the complementary carboxylate group of these ligands. When K33 is altered to a variety of other amino acids, the K33R mutant best stabilizes binding of all of these ligands. However, the r-K33L and r-K33F variants selectively interact with 7-AHpA almost as strongly (ca. 2-fold reduction in binding strength) as wild-type r-[K2tPA]. Increased polarity (K33Q) or a negative charge (K33E) at this sequence position significantly destabilizes binding of omega-amino acids to the muteins. We also found that the r-K33E mutant and, to a lesser extent, the r-K33Q variant selectively interact with a new ligand, 1,6-diaminohexane. These observations show that the omega-amino acid binding site of wtr-[K2tPA] could be redesigned to provide a new binding specificity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The cationic locus on the recombinant kringle 2 domain of tissue-type plasminogen activator that stabilizes its interaction with omega-amino acids. 133 68

Methods were developed to test angiogenic response to human tumor implants and various biologic agents in the cornea of rabbits and non-human primates (Macaca arctoides). Crude PDGF preparations were found to have significant angiogenic effect. Purified, recombinant PDGF preparations were also effective inhibitors (e.g. pentoxifylline (Px) (which also were found to release PgI2 and t-PA) inhibited human tumor implant induced angiogenesis and reduced spontaneous metastases in 3 transplantable murine tumors (Furth-Columbia Wilms' tumor in Furth-Wistar rats, C-1300 neuroblastoma in A/J mice and HM-Kim mammary carcinoma in Wistar rats) but not in the NIH adenocarcinoma in Balb/c mice. Sodium diethyldithiocarbamate (DDTC), a metal complexing agent with special affinity to copper and anti-thyroid as well as, immune stimulating activity was shown to be anti-angiogenic and to potentiate the effect of Px. The anti-fibrinolytic agents epsilon amino caproic acid (EACA) and tranaxamic acid (t-AMCHA) were anti-angiogenic. DDTC and Px were synergistic from this point of view.
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PMID:Studies on tumor induced angiogenesis. 137 68

Using a biochemical technique, the authors characterized and identified a plasminogen activator (PA) derived from tissue extracts of antrochoanal polyp (AP) and paranasal mucous membrane (PMM) with chronic sinusitis. The results of fibrin zymography indicated that the tissue extracts of AP revealed two lytic zones and that those of PMM revealed a single lytic zone on fibrin-agarose plates. One of the AP zones exhibited the same relative mobility as the PMM zone (molecular weight: 65 kd), while the other AP zone had a smaller molecular weight (about 54 kd). Goat immunoglobulin G (IgG) fraction of antihuman uterine tissue-type plasminogen activator (t-PA) inhibited the 65-kd lytic zones of AP and PMM. Antihuman low-molecular-weight urokinase inhibited only the 54-kd lytic zone of AP, and nonspecific goat IgG failed to inhibit any of the lytic zones. On the other hand, 10(-2) mol trans 4-(aminomethyl)cyclohexane-carboxylic acid (t-AMCHA) inhibited all of the lytic zones. No lytic zones could be observed on plasminogen-free fibrin-agarose plates. These findings confirmed that the tissue extracts of PMM contained t-PA, and that those of AP contained both t-PA and urokinase-type plasminogen activator (u-PA). In addition, it appeared that u-PA in inflammatory tissue was related to proliferative changes of the mucous membrane.
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PMID:Presence of urokinase-type plasminogen activator (u-PA) in tissue extracts of antrochoanal polyp. 151 51

Fibrinolytic activity in biopsied colonic mucosa was examined in patients with ulcerative colitis, and most cases were found to have increased tissue fibrinolysis -- due mainly to tissue plasminogen activator -- in the affected mucosa. Five cases, 4 with elevated tissue fibrinolysis and 1 normal, were treated with an antifibrinolytic agent, tranexamic acid (trans-AMCHA) administered as an enema, to inhibit fibrinolysis of the affected mucosa directly. In patients with elevated mucosal fibrinolysis, 2 showed complete remission after tranexamic acid enema alone, and there was one remission in response to combination treatment with oral prednisolone. One case with slightly elevated mucosal fibrinolysis showed clinical improvement, although the radiological findings were unchanged. No response was observed in one case with normal tissue fibrinolysis. It is concluded that tranexamic acid may show a therapeutic effect in ulcerative colitis with elevated mucosal fibrinolysis when administered via an enema, which allows direct contact of the drug with the affected mucosa.
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PMID:Treatment of ulcerative colitis by the direct administration of an antifibrinolytic agent as an enema. 704 40

Aprotinin reduces blood loss after cardiopulmonary bypass, but may sensitize recipients and is expensive. Tranexamic acid, a synthetic antifibrinolytic, has less disadvantages, but opinions differ regarding its efficacy. We studied three groups of patients undergoing cardiopulmonary bypass for coronary disease: recipients of aprotinin (total dose 4.2 x 10(6) kallikrein inhibiting units, n = 14), recipients of tranexamic acid (total dose 20 mg/kg body weight, n = 15), and nonmedicated controls (n = 14) during 24 hours after cardiopulmonary bypass. Compared with controls, aprotinin reduced blood loss, the number of patients requiring transfusions, and the mean number of transfused red cell units (all with p < 0.05), whereas the recipients of tranexamic acid did not differ either from aprotinin recipients or from controls. Aprotinin and tranexamic acid both mitigated the early postoperative reduction of adenosine diphosphate-induced platelet aggregation seen in the controls (p < 0.05). Postoperative increases of plasma concentrations of the prothrombin activation fragment F1 + 2 and the thrombin-antithrombin III complex showed an activation of intravascular coagulation, without any intergroup differences. The balance between concentrations of tissue plasminogen activator and the type 1 plasminogen activator inhibitor disclosed an activation of fibrinolysis, without differences between the groups. The concentrations of D-dimer, a breakdown product of cross-linked fibrin, remained at baseline in the recipients of aprotinin and tranexamic acid but tripled in the controls (p < 0.05). By contrast, the plasma antiplasmin activity was equally depressed in the tranexamic acid and the control groups but decreased less in the recipients of aprotinin (p < 0.05). This discrepancy may reflect the different modes of action of the two agents, which may make aprotinin more efficacious than tranexamic acid in the "nonfibrinolytic" act of protecting platelet function against attack by plasmin during cardiopulmonary bypass.
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PMID:Comparison of the effects of aprotinin and tranexamic acid on blood loss and related variables after cardiopulmonary bypass. 752 12

Platelet-derived growth factor (PDGF)-induced smooth muscle cell (SMC) fibrinolysis is necessary for SMC migration. In order to determine whether the T-cell lymphokines interleukin-4 (IL-4) and gamma interferon (gamma-IFN) affect SMC fibrinolysis and migration, we examined the effects of human recombinant IL-4 and gamma-IFN on human aortic SMC tissue-type plasminogen activator (TPA), urokinase-type plasminogen activator (UPA), and plasminogen activator inhibitor type-1 (PAI-1) antigen production, as determined by enzyme-linked immunosorbent assays. Although IL-4 had no direct effect on SMC TPA antigen, IL-4 potentiated SMC TPA antigen levels and activity in conditioned media and cellular lysates in media containing 2% fetal bovine serum but did not change UPA or PAI-1 production. gamma-IFN attenuated IL-4 augmentation of SMC TPA antigen production in conditioned media, although gamma-IFN itself had no direct effects on SMC TPA and PAI-1 antigen production. IL-4 augmented PDGF induction of SMC TPA antigen. gamma-IFN inhibited PDGF induction of SMC TPA antigen and IL-4 potentiation of this process. gamma-IFN diminished the promigratory effects of both IL-4 and PDGF on in vitro SMC migration. Tranexamic acid, a plasmin inhibitor, abrogated the stimulation of SMC migration by IL-4. Therefore, IL-4 and gamma-IFN modulate the induction of SMC TPA and SMC migration by 2% fetal bovine serum and PDGF.
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PMID:T-cell lymphokines, interleukin-4 and gamma interferon, modulate the induction of vascular smooth muscle cell tissue plasminogen activator and migration by serum and platelet-derived growth factor. 758 21

Fibrinolytic activity of the menstrual fluid is increased in dysfunctional uterine bleeding (DUB). We measured the effect of tranexamic acid on the menstrual blood loss and endometrial fibrinolytic enzymes in women with DUB (> 80 ml menstrual loss/cycle). Endometrial biopsies were taken between 24 and 36 hours after the onset of menstruation. Enzyme activity was assayed by measuring the rate of conversion of Glu-plasminogen to plasmin, using a chromogenic plasmin substrate. Antigen levels were measured using an enzyme linked immunoassay (ELISA) technique. Tranexamic acid reduced menstrual blood loss by 58% (p < 0.05). Endometrial tissue plasminogen activator activity and antigen and plasminogen activator inhibitor--type 1 antigen levels were significantly decreased by tranexamic acid. The effect of tranexamic acid on the fibrinolytic enzymes at local endometrial level may be responsible for its success in the treatment of menorrhagia.
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PMID:The effect of tranexamic acid on measured menstrual loss and endometrial fibrinolytic enzymes in dysfunctional uterine bleeding. 812 12

The involvement of specific aspartic acid (D) and glutamic acid (E) residues of the recombinant (r) kringle 2 (K2) domain of tissue-type plasminogen activator (tPA) in stabilizing its interaction with omega-amino acid ligands has been assessed by examination of these binding events subsequent to site-directed mutagenesis of the relevant amino acid residues. We have expressed and purified nonconservative alanine (A) replacement mutants at the following amino acid sequence locations in r-K2tPA:E17 (r-[K2tPA/E17A]), E75 (r-[K2tPA/E75A]), and D78 (r-[K2tPA/D78A]). More conservative E for D replacements were generated at the only other anionic (at neutral pH) amino acids of r-[K2tPA], viz., D57 (r-[K2tPA/D57E]) and D59 (r-[K2tPA/D59E]). Each of these variant polypeptides was then utilized for binding investigations with a series of omega-amino acids. No substantial differences were found in the binding constants (pH 8.0, 25 degrees C) for the ligands, 6-aminohexanoic acid (6-AHxA), 7-aminoheptanoic acid (7-AHpA), L-lysine, and trans-(aminomethyl)cyclohexane-1-carboxylic acid (AMCHA), among wild-type (wt) r-K2tPA, r-[K2tPA/E17A], r-[K2tPA/E75A], and r-[K2tPA/D78A]. On the other hand, dramatic effects on this same binding were observed in recombinant mutants with alterations at D57 and D59. In these cases, even with the most conservative replacements, i.e., r-[K2tPA/D57E] and r-[K2tPA/D59E], the Kd values for these ligands were increased approximately 3-6-fold and 18-85-fold, respectively. NMR analysis of these variants suggested that no substantial gross conformational changes occurred as a result of the mutations made, but some localized alterations in amino acid microenvironments did take place.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific anionic residues of the recombinant kringle 2 domain of tissue-type plasminogen activator that are responsible for stabilization of its interaction with omega-amino acid ligands. 838 82

The effect of PRAP-1, a Fab-fragment of a PAI-1-inhibiting polyclonal antibody, on thrombus size and arterial blood flow was studied in a rat model of arterial thrombosis. It was shown that exposure of the carotid artery to FeCl3 led to the rapid formation of an occlusive thrombus with a morphology similar to that of arterial thrombi found in humans. Tranexamic acid (50 mg/kg), an inhibitor of fibrinolysis, increased thrombus size (p = 0.014) when given intravenously (i.v.) prior to the FeCl3-exposure. Heparin (1000 U), when given i.v. after FeCl3, did not affect the thrombus size per se, but caused a reduction in the interindividual variation of the size of the thrombus (p < 0.05). Thus, heparin was included in all the subsequent experiments. An i.v. infusion of t-PA (1 mg/kg/h), starting before thrombus formation, induced a 3.3 fold increase in the perfusion rate (p = 0.006) and a 67% reduction in the thrombus size (P < 0.001). PRAP-1, an inhibitor of rat PAI-1 activity, was given i.v. as a bolus followed by an infusion. Two doses of PRAP-1 were studied (7.5 and 15 mg/kg/h), and the administration of the PAI-1 inhibitor was started 10 min before FeCl3. The lower PRAP-1 dose caused a 3.8 fold increase in perfusion rate (p = 0.036), a 1.44 fold increase in the time to occlusion (p = 0.034), and the thrombus size was decreased by 18% (p = 0.104). The corresponding effects of the high PRAP-1 dose were a 6.5 fold increase in perfusion rate (p < 0.001), a 1.6 fold increase in time to occlusion (p = 0.038) and a 32% reduction in thrombus size (p = 0.016). It is concluded that an inhibitor of PAI-1 activity, PRAP-1, caused a moderate decrease in thrombus size and partly restores blood flow in a rat model of arterial thrombus. This finding suggests a potential role for an inhibitor of PAI-1 in the treatment of arterial thrombosis.
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PMID:The Fab-fragment of a PAI-1 inhibiting antibody reduces thrombus size and restores blood flow in a rat model of arterial thrombosis. 918 11


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