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)

The plasminogen activator (PA) activity in various cell lines is suppressed by glucocorticoids. These phenomena are attributed to either a suppression of PA biosynthesis, to an increase of PA inhibitor or to a combination of both. The regulation of urokinase (UK) production in a human pre-B cell lymphoma line, RC-K8, by dexamethasone (Dex) and phorbol myristate acetate (PMA) was investigated. RC-K8 is a cell line which is consistently producing a high molecular weight UK in the conditioned medium (Kubonishi, I., et al: Jpn. J. Cancer Res. 76, 12-15, 1985). The cells were cultured in RPMI-1640 with Dex or PMA for 1-4 days. UK activity was measured using a chromogenic substrate S-2444 and the antigen by an ELISA kit. PAI-1 and PAI-2 antigens were also measured by ELISA kits and the complex between PA and PAI was examined by SDS-PAGE fibrin-zymography. The UK secretion in RC-K8 cells was inhibited by cycloheximide and actinomycin D. PMA at 0.16-1.6 uM up-regulated the UK activity approximately two-fold, parallel with the antigen, whereas Dex at 1-10 uM decreased the UK expression approximately half. These were verified by SDS-PAGE fibrin-zymography. Neither PAI-1, PAI-2 nor PA/PAI complex was detected in the conditioned medium and in the cell lysate. These data suggest that PMA up-regulates the UK secretion without inducing PAIs and the down-regulation of the UK secretion by Dex results from the inhibition of the expression of UK itself but not from the induction of PAIs.
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PMID:Down-regulation of urokinase secretion from a human lymphoma cell line RC-K8 by dexamethasone without inducing plasminogen activator inhibitors. 163 98

Tissue-type plasminogen activator (t-PA) is a thrombolytic agent that directly binds to fibrin formed in clots. In terms of radiolabeling and nuclear imaging, t-PA has several advantages in Tc-99m labeling: it is stable in acidic solution at pH 3, which is suitable for labeling Tc-99m by a method of stannous reduction and blood disappearance after administration is rapid, which is desirable for imaging targets using short-lived radionuclides. Recombinant t-PA was labeled with Tc-99m by a method of stannous reduction without significant degradation of biochemical activity, over 95% of which was retained after the labeling procedure. Labeling efficiency in paper chromatography was over 98%. The moiety of hydrolyzed Tc-99m that was not eluted through the Sephadex column was estimated to be less than 10%. Tc-99m labeled t-PA, however, appeared to become unstable when diluted with normal saline. Nevertheless, in in vitro fibrin binding, Tc-99m labeled t-PA showed high affinity with fibrin: 80% of 100 ng/ml of Tc-99m t-PA bound to 10(-5) mol of the fibrinogen. Preliminary animal studies also showed a concentration of Tc-99m labeled t-PA at fresh thrombi formed in the inferior vena cava. Tc-99m labeled t-PA appears to have potential for thrombus imaging and the preparation of an instant kit.
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PMID:Tc-99m labeled tissue-type plasminogen activator: preparation, stability and preliminary imaging of thrombus-bearing rats. 177 51

Tissue-plasminogen activator (tPA), a protease enzyme that activates the thrombolytic system, and that is known to rise after term delivery, was assayed in 9 women undergoing therapeutic abortion by dilation and curettage. The assay was an ELISA (enzyme-linked immuno-sorbent assay) kit from Biopool AB, Umea, Sweden. The women had received atropine and iv thiamylal anesthesia. The blood was collected in citrate with a 21 gauge needle before, 15 min and 2 hours after surgery, frozen, and assayed simultaneously. t-PA levels were 1.68 ng/mi before, 2.78 ng/mi in 15 minutes (p0.01), and 2.09 ng/mi 2 hours after curettage (n.s.). These results reflect the previously reported increase in fibrin peptide A levels, indicative of thrombin activity, just after abortion.
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PMID:Increase of plasma tissue-plasminogen activator antigen levels after induced abortion. 190 62

Our specific aim was to compare three plasminogen activator-inhibitor type 1 (PAI-1) antigen ELISA kit assays (the Biopool AB, Ltd, TintElize PAI-1 Strip-Well Format; the American Diagnostica, Inc., Imubind 822/1; and the second generation Imubind 822/1S). Within-run coefficients of variation (n = 6) for the TintElize, Imubind 822/1 and Imubind 822/1S methods were 5.5%, 5.9% and 6.8%, respectively. Between-run coefficients of variation for six aliquots per run were 2.9% for TintElize, 3.8% for Imubind 822/1, and 3.5% for Imubind 822/1S. Comparison of the average of duplicate aliquots from hyperlipidaemic patients demonstrated intraclass correlations of 0.75, 0.79 and 0.95 for TintElize vs Imubind 822/1 (n = 39), TintElize vs Imubind 822/1S (n = 39), and Imubind 822/1 vs 822/1S (n = 84), respectively. Lower 95% confidence interval limits of the intraclass correlation were 0.55, 0.48 and 0.93, respectively. Mean PAI-1 antigen values (n = 39) were 12.1, 15.8, 15.8 and 16.0 ng/ml, respectively, for TintElize, TintElize without using the quenching well, Imubind 822/1, and Imubind 822/1S. All three methods were easily performed and exhibited high correlation and reproducibility. A significant systematic bias (P < 0.006) existed between TintElize and TintElize without using the quenching well, Imubind 822/1, and Imubind 822/1S. However, there was no significant bias when TintElize without using the quenching well is compared with Imubind 822/1 (P > 0.8) and to 822/1S (P > 0.8) nor is there significant systematic bias between Imubind 822/1 and 822/1S (P > 0.3). By convention, interchangeability between assay methods suggests that the lower limit of the 95% intraclass correlation confidence interval be greater than 0.75.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Measurement of plasminogen activator inhibitor type 1 antigen: comparison of Tintelize and Imubind methods. 789 23

A new direct labeling technique for proteins with technetium-99m (99mTc) has been developed and makes use of borohydride and stannous chloride. The method is simple and reproducible and gives a high labeling efficiency and high retention of biological activity for proteins, including polyclonal immunoglobulin (Ig), antifibrin monoclonal antibody, tissue type plasminogen activator, fibrinogen and low density lipoprotein (LDL). This method can be used in kit-format and takes about 20 min preparation time at room temperature. Both in vitro and in vivo studies indicate good stability of the label. In vivo, mice and rabbit images show significant accumulation of 99mTc-Ig at an inflammation area, 99mTc-antifibrin at a thrombus site and 99mTc-LDL in atherosclerotic lesions. The method is attractive for routine research and clinical purposes.
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PMID:The labeling of proteins and LDL with 99mTc: a new direct method employing KBH4 and stannous chloride. 824 94

The urokinase type plasminogen activator (u-PA) and the plasminogen activator inhibitor-1 (PAI-1) are among the best second-generation prognostic tissue factors in breast cancer. However, different extraction procedures and assay kits are used in different laboratories. A total of 79 breast tumour tissues stored in liquid nitrogen were analysed in this study. We compared u-PA and PAI-1 levels determined with the American Diagnostics (AD) kit after various extraction procedures. The median cytosolic extraction yield in the presence of 0.4 mol/l KCl, calculated relative to extraction in the presence of 10 ml/l Triton X100 when adapted to standard laboratory working hours (incubation for 2 h instead of 12 h) was 74.4% for u-PA and 85.8% for PAI-1. In addition, the correlations were acceptable. Cytosolic extracts prepared with KCl could permit optimal u-PA and PAI-1 assays while also enabling hormone receptors to be determined with the same specimens. Further studies with clinical data are now necessary to determine the prognostic relevance of this extraction procedure.
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PMID:Comparative study of four extraction procedures for urokinase type plasminogen activator and plasminogen activator inhibitor-1 in breast cancer tissues. 861 70

Measurement of plasminogen, the key component of fibrinolysis system, is one of the basic methods for estimation of fibrinolysis. Methods based on the use of chromogenic substrates are often used in diagnosis. Plasminogen measurements are important for laboratory diagnosis of thrombophilia caused by deficiency or abnormalities of this fiber, for detection and evaluation of the DIC syndrome, and for monitoring the treatment by fibrinolytic preparations (streptokinase, t-PA, urokinase, etc.). An original chromogenic substrate having no foreign analogs has been created at Institute of Genetics and Selection of Industrial Microorganisms and Research Center of Hematology (Moscow). Unlike previously described plasmin substrates, pNa has been obtained by microbiological methods with Russian commercial enzymes subtilisine 72 and megaterine. This paper presents the results of plasminogen measurements in patients with DIC with the use of the original chromogenic substrate. The results were compared with those of tests with Berihrom-Plasminogen diagnostic kit (Behringwerke AG).
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PMID:[A method for determining plasminogen with a Russian chromogenic substrate and its diagnostic significance]. 1087 27

Phospholipase A(2) (PLA(2); EC 3.1.3.4) catalyzes the first step of the production of proinflammatory compounds collectively known as eicosanoids. The binding of phospholipid substrates to PLA(2) occurs through a well formed hydrophobic channel. Surface plasmon resonance studies have shown that niflumic acid binds to Naja naja sagittifera PLA(2) with an affinity that corresponds to a dissociation constant (K(d)) of 4.3 x 10(-5) M. Binding studies of PLA(2) with niflumic acid were also carried out using a standard PLA(2) kit that gave an approximate binding constant, K(i), of 1.26 +/- 0.05 x 10(-6) M. Therefore, in order to establish the viability of PLA(2) as a potential target molecule for drug design against inflammation, arthritis and rheumatism, the three-dimensional structure of the complex of PLA(2) with the known anti-inflammatory agent niflumic acid [2-[3-(trifluoromethyl)anilino]nicotinic acid] has been determined at 2.5 Angstroms resolution. The structure of the complex has been refined to an R factor of 0.187. The structure determination reveals the presence of one niflumic acid molecule at the substrate-binding site of PLA(2). It shows that niflumic acid interacts with the important active-site residues His48 and Asp49 through two water molecules. It is observed that the niflumic acid molecule is completely buried in the substrate-binding hydrophobic channel. The conformations of the binding site in PLA(2) as well as that of niflumic acid are not altered upon binding. However, the orientation of the side chain of Trp19, which is located at the entry of the substrate-binding site, has changed from that found in the native PLA(2), indicating its familiar role.
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PMID:Non-steroidal anti-inflammatory drugs as potent inhibitors of phospholipase A2: structure of the complex of phospholipase A2 with niflumic acid at 2.5 Angstroms resolution. 1630 91

Russell's viper (Vipera russelli, also known as Daboia russelli) is one of the major causes of fatal snakebites. To date, five Daboia russelli subspecies have been recognized. Daboiatoxin (DbTx) is the main lethal phospholipase A(2) (PLA(2)) toxin in the venom of D. russelli siamensis (Myanmar viper) and has strong neurotoxic, myotoxic and cytotoxic activities. DbTx and its homologous neurotoxins viperotoxin F from D. russelli formosensis (Taiwan viper) and vipoxin from the Bulgarian sand viper V. ammodytes meridionalis consist of complexes between a nontoxic acidic PLA(2) protein and an enzymatically active basic PLA(2). DbTx and viperotoxin F are presynaptic toxins, while vipoxin is postsynaptic. The two chains of DbTx have been separated and their PLA(2) enzymatic activity has been measured using the secretory PLA(2) assay kit. The enzymatic activity of DbTx chain B is reduced by 30% of its original activity by chain A in a unimolar ratio, thus indicating that DbTx chain A acts as an inhibitor. The lethal activity of the two chains has also been studied in male albino mice and chain A is less lethal than chain B. The crystal structure of DbTx has also been determined and its structural details are compared with those of the two homologues. Furthermore, an attempt is made to correlate the sequence and structural determinants of these toxins with their enzymatic activities and their pharmacological effects.
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PMID:Structural and pharmacological comparison of daboiatoxin from Daboia russelli siamensis with viperotoxin F and vipoxin from other vipers. 1750 11

The aim of this study was to develop a suitable drug delivery system without Tween 80 and design docetaxel (DTX)-loaded PLA-PEG nanoparticles to improve solubility and decrease side effect of docetaxel. DTX-loaded PLA-PEG nanoparticles were prepared by modified solvent volatilixation method and characterized by particle size distribution, zeta potential and entrapment efficiency. The morphology of DTX loaded PLA-PEG nanoparticles was approximately spherical. The mean diameter and zeta potential of freeze-dried PLA-PEG nanoparticles were 205 +/- 8.1 nm and -24.17 +/- 2.20 mV, respectively. The average entrapment efficiency and drug loading of freeze-dried DTX-loaded PLA-PEG nanoparticles were 91.83 +/- 1.28% and 8.17 +/- 0.35%, respectively. The in vitro release showed that the release from DTX loaded PLA-PEG nanoparticles was slower than from Duopafei and followed the Weibull equation. Cytotoxicity of Duopafei and DTX loaded PLA-PEG nanoparticles was evaluated. Compared with Duopafei, DTX-loaded PLA-PEG nanoparticles showed similar cytotoxicity against three human cancer cell lines and lower toxicity on human normal hepatocellular HL-7702 cells. The apoptosis was detected and measured with Hoechst 33342 and AnnexinV-FITC kit. Compared with Duopafei, DTX-loaded PLA-PEG nanoparticles revealed similar cytotoxicity against A549 cells by inducing similar apoptosis. These results indicated that the PLA-PEG nanoparticles obtained in this study could potentially be exploited as a carrier without Tween 80, which improved drug solubility and decrease side effect of docetaxel.
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PMID:Preparation, characterization, and in vitro evaluation of docetaxel-loaded poly(lactic acid)-poly(ethylene glycol) nanoparticles for parenteral drug delivery. 2136 Nov 32


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