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

In this work, human umbilical vein endothelial cells were cultured on common polystyrene cell culture plates, referred to as control plates, as well as on soft polyvinyl chloride plastics (PVC). Growth of human umbilical endothelial cells (HUVEC) on PVC coated with gelatin, collagen A and heparin plasma was significantly less than that on the control plates coated with the same substance or fibronectin. Cells cultured on PVC produced up to four times as much tissue plasminogen activator than control cells. With reference to plasminogen activator inhibitor 1 (PAI-1), more PAI-1 was released from cells grown on PVC than from those on the control plates coated with gelatin and collagen A. After endotoxin stimulation, the PAI-1 release of HUVEC cultured on PVC was significantly higher than that of control cells with the exception of cells grown on the fibronectin-coated PVC that showed no difference. It is concluded that the type of plastic and coat used to culture HUVEC play a definite role in their growth and function.
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PMID:Effect of polyvinyl chloride plastic on the growth and physiology of human umbilical vein endothelial cells. 887 18

There is frequent use of human and animal proteins as stabilizers during lyophilization of a variety of biological substances with a view to long term stable storage. This report describes the comparative excellent stabilizing effect of a porcine collagen peptide fraction (CPF) during the lyophilization and subsequent storage of three commonly used biological substances, alkaline phosphatase, tissue plasminogen activator and thrombin. The CPF was heated to 150 degrees C for one hour before use. The CPF was shown to have some advantage during lyophilized storage over human serum albumin. Solutions of thrombin stored in CPF at room temperature and at 37 degrees C for one week retained nearly all activity, while storage of thrombin in human serum albumin solution at 37 degrees C lost nearly all biological activity. These preliminary data suggest that porcine CPF is a safe and advantageous stabilizer for addition to biological products with a view to long-term lyophilized storage and short-term liquid storage.
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PMID:A pig collagen peptide fraction. A unique material for maintaining biological activity during lyophilization and during storage in the liquid state. 891 Aug 48

The cellular events causing pathological extracellular matrix (ECM) accumulation in vivo are not well understood. Prolonged serial passage of several cell types in culture leads to increased production of extracellular matrix (ECM) proteins, but the mechanism for these putative fibrotic changes is not known. Here, human fetal glomerular mesangial cells were subjected to serial passage (P) in culture and the expression of ECM proteins, proteases and protease inhibitors was comprehensively evaluated. From P11 through P14, a series of phenotypic changes occurred. Steady-state expression of mRNA for alpha 1 chains of type III and type IV (but not type I) collagen, and for laminin beta 1 and gamma 1, increased 2- to 8-fold, while expression of mRNA for interstitial collagenase (MMP-1) and gelatinase A (MMP-2) virtually ceased. Expression of tissue-type plasminogen activator (tPA) mRNA also decreased markedly. Expression of mRNA for the tissue inhibitor of metalloproteinases (TIMP)-1, and of the smaller of two mRNA species for the PA inhibitor PAI-1, ceased by P14. There was a switch in expression of the two species of TIMP-2 mRNA: whereas the ratio of signal intensity comparing the 3.5 kb mRNA species to the 1.0 kb species was 5:1 up to P11, it was reversed (1:5) at P14 and later. Serial passage also led to changes in protein expression, with increased type IV collagen and laminin, but decreased interstitial collagenase and gelatinase A. The cells showed a progressive increase in staining for type IV collagen. These findings define the appearance of a matrix-accumulating phenotype in later-passage mesangial cells. Matrix expansion in vivo has been associated with increased transforming growth factor (TGF)-beta synthesis; the cells were found to show at least 5-fold increased expression of TGF-beta 1 mRNA from P8 to P16. However, treatment of P9 or P10 cells with graded doses of TGF-beta 1 increased expression of both collagen IV and gelatinase A mRNA and did not alter the ratio of signal intensity for TIMP-2 mRNA species. Thus, assumption of a matrix-accumulating phenotype by these cultured fetal glomerular mesangial cells is not accelerated by exogenous TGF-beta. These data describe an in vitro model of mesangial cell matrix turnover in which matrix accumulation could result from a concerted increase in ECM synthesis and decrease in ECM degradation.
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PMID:Increased expression of extracellular matrix proteins and decreased expression of matrix proteases after serial passage of glomerular mesangial cells. 892 13

Thrombospondin (TSP) is produced by glomerular mesangial cells and one of the extracellular matrix in the mesangium, whereas the physiological role of TSP in mesangial cells is poorly understood. In order to know whether TSP modulates mesangial cell functions, we investigated the effects of TSP on cell adhesion, proliferation, synthesis of extracellular matrix and serine proteinases in cultured human mesangial cells. The substratum of TSP inhibited cell attachment and spreading in a TSP-dose-dependent manner in mesangial cells. Soluble TSP (50 micrograms/ml) also caused the detachment of fully adherent mesangial cells, whereas TSP less than 10 micrograms/ml did not. [3H]-thymidine incorporation into mesangial cells was dose-dependently reduced by TSP. On the other hand, the production of both fibronectin and type IV collagen from mesangial cells was enhanced by TSP. The incubation of mesangial cells with TSP increased the secretion of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), while plasminogen activator inhibitor-type 1 (PAI-1) decreased. These observations indicate that TSP inhibits cell adhesion and proliferation in cultured human mesangial cells. It is also suggested that TSP influences the metabolism of mesangial matrix by modulating both synthesis and degradation of matrix components. Thus, TSP, may be an important mediator of mesangial cell functions in an autocrine fashion.
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PMID:Thrombospondin modulates adhesion, proliferation and production of extracellular matrix in mesangial cells. 892 89

Although heart attack is caused by occlusion of a major coronary artery, some patients have occlusion without heart attack because these patients have sufficient collateral circulation to provide an alternate pathway for blood supply to the myocardium at ischemic risk. The growth of new capillary vessels (angiogenesis) and enlargement of preexisting vessels play an important role in the collateral development. We evaluated the hypothesis that extracellular matrix metalloproteinase (MMP) expression is altered in coronary collateral arteries (0.5-1 mm o.d.) isolated from canine hearts 2-4 months after surgical placement of an ameroid occluder around the proximal left circumflex artery (n = 4), during the development of collateral vessels and restructuring new vessels. Histologic studies (hematoxylin and eosin, trichrome, and van Gieson stains) indicated cellular proliferation and increased collagen and elastin content in collateral vessels compared with comparable-sized unoccluded arterial segments of the left anterior descending (LAD) artery. In situ MMP activity of collateral vessels, measured using denatured collagen in the gel matrix, indicated an increase in total MMP activity in the intima of collateral vessels compared with normal LAD vessels. To further identify the type of MMP, tissue homogenates were prepared from collateral and LAD vessels and analyzed by SDS-PAGE zymography. The results suggest induction of gelatinase A and gelatinase B expression in collateral vessels compared with normal LAD tissue, when identical amounts of total protein were loaded onto each lane in the gel. Based on plasminogen-casein zymography, we observed the tissue plasminogen activator level to be increased in collateral vessels. On the basis of immunoblot and mRNA (Northern blot) analyses, we determined that the MMP-1 level was induced in collateral vessels 2 and 4 months after ameroid occlusion. In contrast with MMP-1, the level of TIMP-1 (tissue inhibitor of metelloproteinases) was decreased significantly (p < 0.001) in collateral compared with LAD vessels, suggesting a role for arterial TIMP in anti-angiogenic activity. Collectively, these results suggest that chronic occlusion of a major coronary artery induces upregulation of vascular remodeling mechanisms subserving collateral development. Increased MMP-2 activity in collaterals may be associated with decreased levels of tissue inhibitor of metalloproteinases and fibrous tissue remodeling following angiogenic and (or) adaptive responses of the myocardium to chronic ischemia.
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PMID:Temporal expression of extracellular matrix metalloproteinases and tissue plasminogen activator in the development of collateral vessels in the canine model of coronary occlusion. 896 Mar 89

To understand the contribution of epidermal melanocytes in the proteolytic potential of human skin, we have studied melanocytes grown in a low-serum medium deprived of phorbol esters, cholera toxin, and other non-physiological supplements. We focused on the plasminogen activation system and certain matrix metalloproteinases (gelatinases). Supposing that the proteolytic activity of cells can influence binding to collagen matrix and its reorganization, we have analyzed these parameters as well. We found that human melanocytes secreted tissue-type plasminogen activator and utilised it to generate cell-bound plasmin. No urokinase-type plasminogen activator was detected in the cultures but its receptor was found in cell extracts. Both the 72 kDa and 92 kDa gelatinases were secreted by the cells and in equal amounts. In addition, melanocytes secreted the wide-spectrum proteinase inhibitor alpha-2-macroglobulin. Melanocytes cast into collagen matrices retained a rounded morphology, did not extend processes, and were unable to contract collagen lattices. As a control, these parameters were investigated in parallel in cultures of human keratinocytes, dermal fibroblasts, and two melanoma cell lines. The obtained characteristics suggest that normal human melanocytes are proteolytically active cells. This function may pertain to skin physiology and pathophysiology.
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PMID:The proteolytic potential of normal human melanocytes: comparison with other skin cells and melanoma cell lines. 901 12

The thrombin inhibitor inogatran is a synthetic peptidomimetic with a molecular weight of 439 dalton. In vitro studies have shown that inogatran is a classical competitive inhibitor of the active site of thrombin with a Ki of 15 x 10(-9) mol/l. Inogatran doubles the thrombin clotting time in human plasma at 20 x 10(-9) mol/l, APTT at 1.2 x 10(-6) mol/l, and prothrombin time at 4 x 10(-6) mol/l. The effects on rat and dog plasma are similar although slightly weaker. IC50 for inhibition of thrombin-induced aggregation of human platelets is 17 x 10(-9) mol/l. Inogatran has no effect on platelet aggregation induced by ADP or collagen. Up to a concentration of 10 x 10(-6) mol/l inogatran does not inhibit t-PA-induced fibrinolysis as seen in an ECLT system. Inogatran has good selectivity for thrombin as compared to several other serine proteases occurring in the blood. It is concluded that the properties of inogatran in vitro make the compound suitable for further studies in animals and man.
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PMID:In vitro effects of inogatran, a selective low molecular weight thrombin inhibitor. 905 87

We previously demonstrated that human gingival fibroblasts (HGF), but not their dermal counterparts, when seeded in retracting fibrin lattices induced intense fibrinolysis that was observed at the earliest stages of contraction and led to complete matrix degradation by day 7 of culture. Our aim was to examine the influence of mechanical forces in such fibrinolytic processes. HGF were seeded in retracting (R) e.g. free floating or non retracting (NR) e.g. anchored fibrin lattices (FL). Cultures were analysed from day 1-12 by phase contrast microscopy and scanning electron microscopy (s.e.m.). Levels of fibrin degradation products (FDP) and tissue plasminogen activator (tPA) accumulating in culture media were quantified by ELISA. Urokinase (uPA) and gelatinase A (MMP2) were identified by zymographic techniques. At the s.e.m. level, vacuolization around some HGF was noticed at the earliest stages of culture for RFL and complete degradation of lattices occurred at day 7. Formation of lysed matrix cavity was far less intense in NRFL even after 12 days of culture. FDP amounts at day 4 of culture were equal to 79 +/- 14 and 8.5 +/- 0.6 micrograms/10(5) cells for RFL and NRFL, respectively; tPA levels were equal to 5.8 +/- 0.6 (RFL) and 2.1 +/- 0.3 ng/10(5) cells (NRFL) and differences were still evident at day 7. The kinetics of tPA production were identical in either retracting fibrin or collagen lattices. On the contrary, uPA and proMMP2 productions were similar in RFL and NRFL. Isometric forces, but not the matrix support, were responsible for accelerated tPA production and fibrinolysis in HGF populated lattices.
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PMID:The rate of fibrinolysis is increased by free retraction of human gingival fibroblast populated fibrin lattices. 907 53

Decidual and placental relaxins have been proposed as autocrine/ paracrine hormones in the remodeling of collagen in the amnion and chorion in the last weeks of pregnancy. The matrix metalloproteinase-1 (MMP-1) is a key enzyme in the degradation of the interstitial collagens which predominate in the fetal membranes. Distribution of the MMP-1 gene and of the MMP-1 protein was shown by in situ hybridization and immunolocalization, respectively, in amnion, chorion, and decidua collected from patients before the onset of spontaneous labor. The distribution of MMP-1 in the chorionic cytotrophoblast and decidua coincided with that of the human relaxin receptor, detected by tissue section autoradiography in tissues collected at the same stage of pregnancy. Fetal membrane explants were used to study the effect of exogenous human relaxin H2. These responded by a dose-dependent increase in expression of the MMP-1 gene, in its secreted protein, and in its enzyme activity in the medium. A similar dose-dependent increase in the tissue plasminogen activator (tPA) gene and protein upon exposure of the explants to relaxin H2 suggested a coordinated cascade system, resulting in increases in secreted activities of MMP-1, MMP-3 (stromelysin), and MMP-9 (gelatinase B). There was no effect on the genes or proteins for MMP-2 (gelatinase A) or tissue inhibitor of metalloproteinase-1 (TIMP-1), showing the specificity of the response. This coordinated regulation by relaxin H2 of tPA, MMP-1, MMP-3, and MMP-9 would result in more complete degradation of the fetal membrane extracellular matrix components.
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PMID:An autocrine/paracrine role of human decidual relaxin. I. Interstitial collagenase (matrix metalloproteinase-1) and tissue plasminogen activator. 909 59

High-density lipoproteins (HDL) can bind and neutralize lipopolysaccharides (LPS) in vitro and in vivo. HDL can also affect fibrinolytic activity and can directly influence platelet function by reducing platelet aggregation. In this study, the effects of reconstituted HDL (rHDL) on LPS-induced coagulation, fibrinolysis and platelet activation in humans were investigated. In a double-blind, randomized, placebo-controlled, cross-over study, eight healthy male volunteers were injected with LPS (4 ng/kg) on two occasions, once in conjunction with rHDL (40 mg/kg, given as a 4 h infusion starting 3.5 h prior to LPS injection), and once in conjunction with placebo. rHDL significantly reduced LPS-induced activation of coagulation (plasma levels of prothrombin fragment F1 + 2) and fibrinolysis (plasma levels of tissue type plasminogen activator antigen, t-PA). No effect was observed on LPS-induced inhibition of the fibrinolytic pathway (PAI-1) or on the transient thrombocytopenia elicited by LPS. Furthermore, rHDL treatment significantly enhanced the inhibition of collagen-stimulated inhibition of platelet aggregation during endotoxemia, but had no such effect on arachidonate-stimulated platelet aggregation. rHDL treatment per se also reduced collagen-induced platelet aggregation. These results indicate that rHDL modifies the procoagulant state associated with endotoxemia.
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PMID:Differential effects of reconstituted high-density lipoprotein on coagulation, fibrinolysis and platelet activation during human endotoxemia. 915 86


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