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)

I have experienced 35 cases of DIC in my department during last 8 years. These cases were divided into a septic and non-septic groups based on their back-ground, and compared their clinical symptoms and various laboratory findings. The results showed the septic DIC group could be characterized as follows: (1) impairment of the vital organs was more clearly manifested, while hemorrhagic symptoms were mild, (2) the laboratory tests showed almost no tendency for fibrinogen or alpha 2-PI to be decreased or PIC to be increased, (3) the blood PAF (Platelet Activating Factor) level was clearly higher and showed an inverse relationship with the platelet count. On the basis of these clinical findings, I speculated septic DIC involves suppression of secondary fibrinolysis and participation of PAF. In experiment A, I investigated the effects of endotoxin (Et) on the activity of plasminogen activator (PA) in the rabbit renal cortex. In both in vitro and in vivo systems, I could demonstrate the renal cortex PA activity was significantly suppressed by Et. Then, in experiment B, I could confirm, (1) PAF caused a drop in the blood pressure and a decrease in the platelet count that were similar to those induced by Et, and that Et caused a decrease in the platelet count that was inversely accompanied by an increase in PAF, (2) PAF antagonist showed greater efficacy than a protease inhibitor in suppressing the decrease in the blood platelet count.
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PMID:[Clinical and experimental studies of septic DIC in surgical patients, in terms of its characteristic features and pathogenesis]. 787 83

In previous studies, we have shown that administration of monoclonal antibody (MoAb) C6B7 against human factor XII to baboons challenged with a lethal dose of Escherichia coli abrogates activation of the contact system and modulates secondary hypotension. To evaluate the contribution of activated contact proteases to the appearance of other inflammatory mediators in this experimental model of sepsis, we studied the effect of administration of MoAb C6B7 on activation of complement and fibrinolytic cascades, stimulation of neutrophil degranulation, and release of the proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Activation of the complement system, as reflected by circulating C3b/c and C4b/c levels, was significantly reduced in five animals that had received MoAb C6B7 before a lethal dose of E coli as compared with five control animals that had been given a lethal challenge only. Inhibition of contact activation also modulated the fibrinolytic response, since the release of tissue-type plasminogen activator (t-PA) and the appearance of plasmin-alpha2-antiplasmin (PAP) complexes into the circulation was significantly attenuated upon pretreatment with anti-factor XII MoAb. In contrast, plasma levels of plasminogen activator inhibitor (PAI) were modestly enhanced in the treatment group. Degranulation of neutrophils, as assessed by circulating elastase-alpha1-protease inhibitor complexes, and release of IL-6 but not of TNF-alpha was decreased in anti-factor XII-treated animals. Observed differences in the inflammatory response between treatment and control groups were not likely due to different challenges, since the number of E coli that had been infused, as well as circulating levels of endotoxin after the challenge, were similar for both groups. These data suggest that activation of the contact system modulates directly or indirectly various mediator systems involved in the inflammatory response during severe sepsis in nonhuman primates.
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PMID:Inhibition of factor XII in septic baboons attenuates the activation of complement and fibrinolytic systems and reduces the release of interleukin-6 and neutrophil elastase. 863 Mar 96

Induction of the urokinase type plasminogen activator receptor (uPAR) promotes cell adhesion through its interaction with vitronectin (VN) in the extracellular matrix, and facilitates cell migration and invasion by localizing uPA to the cell surface. We provide evidence that this balance between cell adhesion and cell detachment is governed by PA inhibitor-1 (PAI-1). First, we demonstrate that uPAR and PAI-1 bind to the same site in VN (i.e., the amino-terminal somatomedin B domain; SMB), and that PAI-1 competes with uPAR for binding to SMB. Domain swapping and mutagenesis studies indicate that the uPAR-binding sequence is located within the central region of the SMB domain, a region previously shown to contain the PAI-1-binding motif. Second, we show that PAI-1 dissociates bound VN from uPAR and detaches U937 cells from their VN substratum. This PAI-1 mediated release of cells from VN appears to occur independently of its ability to function as a protease inhibitor, and may help to explain why high PAI-1 levels indicate a poor prognosis for many cancers. Finally, we show that uPA can rapidly reverse this effect of PAI-1. Taken together, these results suggest a dynamic regulatory role for PAI-1 and uPA in uPAR-mediated cell adhesion and release.
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PMID:Is plasminogen activator inhibitor-1 the molecular switch that governs urokinase receptor-mediated cell adhesion and release? 883 Jul 83

Vascular pathophysiology at the sites of bacterial infection and cancerous tissues share numerous common events similar to inflammatory tissue. Among them enhanced vascular permeability is the universal and hallmark event mediated by bradykinin. All 16 or more bacterial or fungal proteases we have examined activated one or more steps of the kinin generating Hageman-factor-kallikrein cascade. In the meantime, most of the microbial proteases rapidly inactivated various plasma inhibitors such as alpha 1-protease inhibitor and alpha 2-macroglobulin. In addition to the extracellular proteases, bacterial cell wall components (negatively charged LPS) of gram-negative bacteria and teichoic acid moieties of gram-positive bacteria activate the Hageman-factor-kallikrein system and exert hypotensive effects via kinin generation. Endotoxin (LPS) also induces nitric oxide synthase (NOS) which appears to exhibit a rather slow, but significant, effect in relaxing the vascular tone of the infected animal (thus hypotension). Furthermore, bacterial proteases can activate the matrix metalloproteinase (collagenase) resulting in exacerbation of tissue injury in the diseased animal. Many tumor cells or tissues excrete plasminogen activator, and hence activate plasminogen. The plasmin thus generated activates procollagenases, as well as the Hageman-factor-kallikrein system, resulting in pronounced extravasation. Fluid accumulation in pleural and ascitic carcinomatoses is largely due to the activated bradykinin-generating system. We can also demonstrate and control enhanced vascular permeability using kallikrein inhibitors, especially the polymer-conjugated soybean trypsin inhibitor which exhibits a prolonged plasma t1/2, kinin antagonists, NOS inhibitors, NO scavengers, inhibitors of prostaglandins and others. Bacterial proteases induce shock in mice which can be prevented by the soybean trypsin inhibitor by blocking the kallikrein-kinin cascade. Therapeutic use of kinin antagonists and a kallikrein inhibitor has been made for infectious diseases such as septicemia and in tumor pathology.
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PMID:Bradykinin and nitric oxide in infectious disease and cancer. 885 54

Activation of covalently intact plasminogen by tissue-type plasminogen activator (tPA) is facilitated by a majority of proteins subjected to denaturing conditions. Except for heat-denatured apoferritin, the denatured proteins examined require partial proteolysis by plasmin for cofactor activity. The same proteins in their native state are resistant to proteolysis with plasmin and develop no activity. Denatured preparations of apoferritin, antithrombin, alpha1-protease inhibitor, alpha2-macroglobulin, and albumin also accelerate des(1-77)-plasminogen activation by tPA. The rate enhancements are comparable with that of the fibrin(ogen) fragments on a w/w basis. The cofactor activities are inhibited by 6-aminohexanoate and inactivated by pepsin. Analysis of heat-denatured apoferritin and albumin preparations by ultracentrifugation and gel chromatography indicates that cofactor is associated predominately with aggregates, which have binding capacity for both tPA and zymogen. Heat-denatured albumin pretreated with plasmin decreases K(M) and increases k(cat) for both intact plasminogen and des(1-77)-plasminogen activation by tPA, yielding catalytic efficiencies in excess of 8 x 10(3) M(-1) s(-1) and 2 x 10(4) M(-1) s(-1), respectively. Because of enhanced plasmin-catalyzed proteolysis of plasminogen to des(1-77)-plasminogen, activation by urokinase-type plasminogen activator is also facilitated by denatured proteins; activation of des(1-77)-plasminogen is not affected. It is concluded that denatured proteins serve as both cofactors and substrates in the fibrinolytic system, and that enhancement of plasminogen activation by denatured proteins is mechanistically indistinguishable from that observed with fibrin.
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PMID:Denatured proteins as cofactors for plasminogen activation. 926 48

The multiligand receptor, low density lipoprotein receptor-related protein (LRP), is implicated in processes such as atherosclerosis and fibrinolysis through its mediation of the catabolism of lipoproteins, proteases, and protease inhibitor complexes. The hepatoma cell line Hep G2 expresses LRP and has been used widely to investigate the catabolism of LRP ligands including tissue-type plasminogen activator (tPA). However, the mechanism and degree by which tPA interacts with Hep G2 has been reported with some inconsistencies which may reflect variation in their level of LRP expression. To address this possibility we characterized, antigenically and functionally, LRP expression in high and low passage Hep G2 cells both from the parental line (ATCC sourced) and a cloned subline, a16. The LRP contribution to 125I-tPA binding varied from 65% for high passage a16 cells, to 20% for low passage parent cells as quantified by inhibition in the presence of 39-kD receptor associated protein (RAP) which prevents binding of all known LRP ligands. The same trend in LRP expression among Hep G2 sublines was further evident in their ability to degrade 125I-tPA and survive Pseudomonas exotoxin A challenge. These results imply wide variability in basal LRP expression among Hep G2 lines dependent on cell lineage and long-term culture conditions.
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PMID:Low density lipoprotein receptor-related protein (LRP) expression varies among Hep G2 cell lines. 961 Sep 60

Metastasis is a characteristic and fatal feature of human malignancies. Its regulation is therefore of the utmost significance to clinicians. The present study was undertaken to determine whether a legume-derived protease inhibitor (PI) of trypsin/chymotrypsin, the field bean PI (FBPI), also has plasmin inhibitory activity and can inhibit pulmonary metastasis of B16F10 melanoma cells systemically injected into BDF1 mice. Two approaches to the problem were made. In the first, the melanoma cells were exposed to two different concentrations of the FBPI prior to their inoculation into animals. In the second, the mice were treated intraperitoneally with FBPI at a dose of 100 mg/kg body weight once daily for 10 days, the treatment being started soon after the systemic injection of the tumour cells. The study revealed that both modes of FBPI treatment could effectively block lung cell metastasis by the melanoma cells and that FBPI has plasmin blocking activity. Since urokinase type plasminogen activator and plasmin are known to play significant roles in tumour cell metastasis, the dose-dependent inhibitory effect of FBPI with antiplasmin activity on tumour cell metastasis suggests that its antimetastatogenic action is probably mediated through its plasmin inhibitory action.
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PMID:The field bean protease inhibitor has the potential to suppress B16F10 melanoma cell lung metastasis in mice. 971 30

An ELISA was developed and validated for the quantitation of lanoteplase in human citrated plasma. The ELISA employed a monoclonal anti-lanoteplase antibody absorbed onto 96-well microtiter plates to capture lanoteplase in citrated human plasma samples containing PPACK, a protease inhibitor. The captured lanoteplase was detected using a biotinylated rabbit anti-lanoteplase polyclonal antibody. The standard curve range in human plasma for the ELISA was 7-100 ng/ml. Assessment of individual standard curve variability indicated reproducible responses with r2 values of > or = 0.985. The accuracy (% DEV) and precision (%RSD) estimates for the ELISA based on the predicted values from quality control (QC) samples were within 7.3% and 11%, respectively. Cross-reactivity with t-PA was determined to be less than 11% by ELISA. The stability of lanoteplase was established in human citrated PPACK plasma for 24 hours at 4 degrees C, for 2 months at -20 degrees C, for 22 months at -70 degrees C, three weeks at room temperature, and through four freeze/thaw cycles. To quantify lanoteplase plasminogen activator (PA) activity, a commercially available chromogenic activity assay was also validated. This method and its application is described briefly here. The lanoteplase ELISA as well as the commercial activity method were successfully employed to evaluate the pharmacokinetic parameters of lanoteplase in support of clinical Phase II/III studies.
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PMID:Validation of an ELISA for the quantitation of lanoteplase, a novel plasminogen activator. 1059 57

We have investigated plasmin mediated proteolysis associated with trophoblast invasion during early stages of pregnancy in the rhesus monkey. In situ hybridization and immunocytochemical localization were used to define the cellular and tissue distribution of urokinase plasminogen activator (uPA), plasminogen activator inhibitor type 1 (PAI-1) and 2 (PAI-2) and urokinase receptor in early monkey placenta and uterus. Our results indicate: (1) uPA is expressed in proliferating and invasive cytotrophoblast located in chorionic villi as well as in extravillous trophoblast associated with uterine arterioles. This raises the possibility that urokinase may play an important role in trophoblast invasion. (2) PAI-1 mRNA is specifically localized in two areas where invasive trophoblast cells encounter maternal tissue directly. The extravillous cytotrophoblast cells at the maternofetal junction express PAI-1 mRNA. The invasive endovascular trophoblast cells within the uterine arterioles also express PAI-1 mRNA. The location sensitive expression of PAI-1 mRNA at the maternofetal junction may imply a protective function of this protease inhibitor that might be induced through interaction with decidual cells. (3) Urokinase receptor antigen has also been found at the maternofetal junction and in endovascular trophoblast cells of the invaded maternal blood vessel. (4) PAI-2 immunoreactivity is found in association with cytotrophoblast cells in anchoring choronic villi suggesting its association with early placentation. In conclusion, we propose that the plasmin/plasminogen activator system may not only regulate extracellular matrix degradation, but also modify migration and invasive behaviour of extravillous trophoblast cells, during early placentation.
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PMID:Expression of urokinase, plasminogen activator inhibitors and urokinase receptor in pregnant rhesus monkey uterus during early placentation. 1073 41

Serine proteases are involved in many processes in the nervous system and specific inhibitors tightly control their proteolytic activity. Thrombin is thought to play a role in tissue development and homeostasis. To date, protease nexin-1 is the only known endogenous protease inhibitor that specifically interferes with thrombotic activity and is expressed in the brain. In this study, we report the detection of a novel thrombin inhibitory activity in the brain of protease nexin-1(-/-) mice. Purification and subsequent analysis by tandem mass spectrometry identified this protein as the phosphatidylethanolamine-binding protein (PEBP). We demonstrate that PEBP exerts inhibitory activity against several serine proteases including thrombin, neuropsin, and chymotrypsin, whereas trypsin, tissue type plasminogen activator, and elastase are not affected. Since PEBP does not share significant homology with other serine protease inhibitors, our results define it as the prototype of a novel class of serine protease inhibitors. PEBP immunoreactivity is found on the surface of Rat-1 fibroblast cells and although its sequence contains no secretion signal, PEBP-H(6) can be purified from the conditioned medium upon recombinant expression.
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PMID:The phosphatidylethanolamine-binding protein is the prototype of a novel family of serine protease inhibitors. 1103 91


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