Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new phenomenon is described: Whole blood clots lyse faster in the plasma of the same donor than in another donor's plasma. We have confirmed this finding in 68 healthy volunteers by a standardized, pair-wise analysis and have found a mean difference in clot weights of 8.8 +/- 0.99% (SEM, p < 0.0001) after 6 h of urokinase-induced (200 U/ml) clot lysis. No difference was found in a group of 7 pairs of identical twins. Further analysis revealed that increasing concentrations of platelets in the plasma reduced the difference significantly but did not abolish it. A 1:1 mixture of autologous with homologous plasma reduced the autologous advantage by almost 50%, thus making an inhibitor unlikely. The absence of cellular components in clots of platelet-poor plasma resulted in the loss of the advantage after 2 h of lysis, but not in the early phase. We conclude that there is a clear advantage of autologous over homologous clot lysis. Potential mechanisms are discussed and include an increased affinity of enzymes for their substrates in a given individual.
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PMID:Whole blood clot lysis: enhanced by exposure to autologous but not to homologous plasma. 809 91

Isometric contraction to direct supramaximal tetanic stimulation of the anterior tibialis (AT) muscle was measured in 50 New Zealand White rabbits after ischemia and reperfusion. Ischemia was produced unilaterally by collateral ligation and temporary inflow control until AT muscle function decreased to < 5% of contralateral (control) AT muscle and the ischemic interval was recorded. Reperfusion was carried out in one of the following ways: group I (n = 20), release of vascular clamps (blood reperfusion [BR]); group II (n = 10), release of vascular clamps and simultaneous intraarterial administration of 50,000 units of urokinase (urokinase reperfusion [UR]); group III (n = 10), release of vascular clamps and simultaneous administration of 50,000 units of urokinase and 28 mg (5 units) of purified rabbit plasminogen (urokinase plasminogen reperfusion [UPR]); and group IV (n = 10), animals defibrinated to < 50 mg/dl with ancrod prior to ischemia and received BR (ancrod blood reperfusion [ABR]). During reperfusion, function was recorded every 60 min for 2 hr. Recovery of experimental muscle function is expressed as the percentage of contralateral control limb function. The mean ischemic interval (mean +/- SEM), to achieve < 5% of contralateral control limb function, was 206.7 +/- 9.9, 209.5 +/- 16.6, 221.7 +/- 12.5, and 272.0 +/- 14.2 min for animals in groups I-IV, respectively. The mean experimental muscle function (mean +/- SEM) following the ischemic interval was 3.2 +/- 0.8, 4.5 +/- 1.4, 4.4 +/- 1.2, and 3.3 +/- 1.0 for groups I-IV, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of hypofibrinogenemia and fibrinolysis on skeletal muscle function after ischemia and reperfusion. 827 73

The capacity of macrophages to influence directly and indirectly fibrinolytic processes in atherosclerosis was studied using macrophages isolated from atherosclerotic plaques of patients undergoing surgical repair of distal aortic and femoral arteries. These cells were characterized by their morphology, adherence, esterase positivity, and expression of CD14 antigen. Production of plasminogen activator inhibitor type-1 (PAI-1) by plaque macrophages (6.7 +/- 2.7 ng/10(5) cells/24 hours [mean +/- SEM]) was significantly greater than PAI-1 production by blood monocytes isolated simultaneously from the same patients (1.8 +/- 1.5 ng/10(5) cells/24 hours). Production of tissue type plasminogen activator and urokinase type was not augmented compared to blood monocytes. Conditioned medium from cultured plaque macrophages significantly increased production of PAI-1 by endothelial cells (85 +/- 11% above basal) and vascular smooth muscle cells (25 +/- 10%) in vitro. This response was significantly greater than the response to monocyte-conditioned medium (endothelial cells 38 +/- 11%, vascular smooth muscle cells 2.5 +/- 2.0%). Stimulation of endothelial cell PAI-1 production by macrophage-conditioned medium was partially inhibitable by a monoclonal antibody to transforming growth factor-beta. Tissue type plasminogen activator production by endothelial cells and vascular smooth muscle cells was not affected by plaque macrophage- or monocyte-conditioned medium. Urokinase type plasminogen activator production by endothelial cells and vascular smooth muscle cells was undetectable in control medium and was augmented to similar levels in response to plaque macrophage- and monocyte-conditioned media. These results demonstrate upregulation of PAI-1 production by macrophages in atheromatous plaques and the capacity of soluble products from plaque macrophages to upregulate PAI-1 production by endothelial cells and vascular smooth muscle cells in vitro. These data suggest that macrophages in atherosclerotic plaques may inhibit thrombolysis both directly and indirectly by effects of their soluble products on endothelial cells and vascular smooth muscle cells.
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PMID:Atheromatous plaque macrophages produce plasminogen activator inhibitor type-1 and stimulate its production by endothelial cells and vascular smooth muscle cells. 836 83

The occurrence of type-1 plasminogen activator inhibitor (PAI-1) in human cerebrospinal fluid (CSF) has not previously been reported. As a member of the serpin superfamily of serine protease inhibitors and an acute phase response component, PAI-1 has powerful potential roles in nervous system homeostasis. We have detected this serpin antigen using a polyclonal anti-PAI-1 antibody in normal human CSF. In Western blotting, PAI-1 in several CSF samples appears as a two-band antigen of Mr = 54 and 35 kDa, presumably the intact and proteolytic fragment, respectively. In vitro complex formation studies confirm that the 54 kDa form of PAI-1 interacts with 125I-urokinase after activation with SDS, but the 35 kDa form does not. Quantification of total PAI-1 antigen in 18 normal human CSF samples by ELISA reveals a mean value of 1.0 +/- 0.07 (SEM) micrograms/dL, indicating that a relatively low concentration of the inhibitor occurs in normal human CSF. This information should now allow comparison of PAI-1 levels and activity in various neurologic disorders.
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PMID:Plasminogen activator inhibitor 1, the primary regulator of fibrinolysis, in normal human cerebrospinal fluid. 845 10

Tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), and streptokinase were evaluated for their ability to reduce postsurgical adhesion formation in a rat uterine horn devascularization and serosal injury model in a blinded, randomized study. Small doses of tPA, uPA, or streptokinase were delivered over approximately a 4-day period either from a biodegradable hydrogel matrix or as four daily intraperitoneal injections. The hydrogel was formed upon the uterine horns by photopolymerization of an aqueous precursor solution containing dissolved drug. A control group that received no treatment had an average extent of adhesion formation of 72 +/- 15% (mean +/- SEM, percentage of the length of the uterine horns involved in adhesions). Application of this formulation of the hydrogel alone reduced the extent of adhesion formation to 22 +/- 10% by functioning as a mechanical barrier. When tPA was released from the hydrogel, adhesion formation was reduced to 4 +/- 3%, while when tPA was given by intraperitoneal injection, adhesion formation was only reduced to 49 +/- 8%. Local delivery of urokinase reduced adhesion formation to 6 +/- 6%, but intraperitoneal injection of urokinase did not reduce adhesion formation. Streptokinase did not reduce adhesion formation when administered by intraperitoneal injection and increased adhesion formation to 45 +/- 9% when locally released relative to the hydrogel alone. These results suggest that both tPA and uPA may be used to prevent adhesion formation when delivered locally.
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PMID:Local release of fibrinolytic agents for adhesion prevention. 853 78

Mice with combined homozygous deficiency of tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) (T-U-), of t-PA and plasminogen activator inhibitor-1 (PAI-1) (T-P-), of u-PA and PAI-1 (U-P-) or of t-PA, u-PA, and PAI-1 (T-U-P-) were generated by inbreeding of mice with the respective deficiencies. Homologous recombination at the t-PA, u-PA and PAI-1 locus was verified by Southern blot analysis of genomic tail tip DNA, and confirmed by measurement of antigen levels in plasma or urine. T-P- and U-P- mice were apparently healthy and fertile. T-U- mice showed extensive fibrin deposition with calcification in the liver, whereas T-U-P- mice were significantly (p < 0.001) less affected. Spontaneous in vivo clot lysis measured 4 h after injection of a 125I-fibrin-labeled clot prepared from plasma of wild-type (WT) mice into the jugular vein, was (mean +/- SEM of n experiments) 2 +/- 1% (n = 8) for T-P-, 49 +/- 6% (n = 9) for U-P-, 1 +/- 1% (n = 4) for T-U- and 3 +/- 3% (n = 3) for T-U-P- mice, as compared to 32 +/- 4% (n = 10) for WT, 1 +/- 0% (n = 7) for T-, 30 +/- 5% (n = 5) for U- and 58 +/- 10% (n = 6) for P- mice. Plasminogen-dependent lysis of 125I-fibrin-labeled matrix and of 3H-proline-labeled subendothelial matrix (mean +/- SEM; n = 4 to 6) was lower with thioglycollate-stimulated macrophages obtained from U-P- mice (22 +/- 7% and 5 +/- 1%, respectively), as compared to WT mice (57 +/- 14% and 18 +/- 5%, respectively) and T-P- mice (87 +/- 6% and 27 +/- 4%, respectively). A similar decrease was previously observed with U- mice, but not with T- or P- mice. Thus, the phenotype of mice with combined deficiency of t-PA and PAI-1 or of u-PA and PAI-1 is similar to the phenotype observed in mice with single deficiency of the plasminogen activator. Additional deletion of PAI-1 does not affect viability, fertility, macrophage function or thrombolytic potential of the single deficient mice. Additional deletion of PAI in mice with combined deficiency of t-PA and u-PA does not restore the deficient in vivo fibrinolytic capacity, but significantly reduces the thrombotic phenotype, as revealed by fewer, smaller and less calcified fibrin deposits in the liver.
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PMID:Biological effects of combined inactivation of plasminogen activator and plasminogen activator inhibitor-1 gene function in mice. 856 Apr 24

A critical component in the regulation of thrombus formation and clearance is the balance between tissue plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1). An increase in the plasma concentration of PAI-1 has been proposed as a risk factor in thrombotic disease. Inhibition of PAI-1 activity may have utility in the treatment of thromboembolic disease. We report here the evaluation of three diketopiperazine-based low molecular weight inhibitors of PAI-1 activity (XR334, XR1853 and XR5082). In vitro these compounds reversed the inhibitory effects of PAI-1 against both tPA and urokinase (UK) (IC50: 5 to 80 muM). In contrast, other serpin-serine protease interactions, including alpha 1-antitrypsin-trypsin, alpha 2-antiplasmin- plasmin and antithrombin-thrombin, were not affected, neither did these inhibitors affect global tests of haemostasis. In the light of this promising in vitro profile these compounds were evaluated in a standard radioisotopic assay of clot lysis in whole rat blood following intravenous administration. In this assay these compounds dose-dependently enhanced fibrinolysis ex vivo. After intravenous bolus administration XR334, XR1853 and XR5082 at 5 mg/kg increased clot lysis by 32.0 +/- 5.1% SEM (n = 25, p < 0.01), 36.7 +/- 3.5% SEM (n = 36, p < 0.01) and 60.0 +/- 2.8% SEM (n = 17, p < 0.01) respectively compared to vehicle. Intravenous infusion of these compounds (1 mg/kg/min for 20 min) significantly prolonged (approximately twofold) the time to blood vessel occlusion in the rat electrically-stimulated carotid artery thrombosis model. Thus, these low molecular weight inhibitors of PAI-1 activity enhanced fibrinolysis ex vivo and protected against thrombus formation in the rat.
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PMID:Evaluation of a low molecular weight modulator of human plasminogen activator inhibitor-1 activity. 872 28

The estimation of the activity of circulating tissue-type plasminogen activator (t-PA) using the Coaset t-PA or Spectrolyse/fibrin t-PA reagent kits involves incubation of plasma with excess plasminogen in the presence of human fibrin fragments, and detection of the plasmin generated by an end-point amidolytic assay. We examined the interference of endogenous inhibitors such as plasminogen activator inhibitor-1 (PAI-1) and alpha 2-antiplasmin, and that of an endogenous activator namely single-chain urokinase-type plasminogen activator (scu-PA) on the Coaset t-PA assay. An extra acidification of the samples already collected into an acidified anticoagulant raised the mean Coaset t-PA activity of 15 samples from 1.39 +/- 0.25 (mean +/- SEM) to 1.71 +/- 0.27 (P < 0.001). In twelve of these samples, the PAI-1 and alpha 2-antiplasmin activities were determined. The increase in the t-PA activity by acidification was found to correlate inversely with PAI-1 (r = -0.66; n = 12; P = 0.019) but not with alpha 2-antiplasmin, demonstrating that the extra acidification step released t-PA from the t-PA-PAI-1 complex, but had no influence on the endogenous alpha 2-antiplasmin in the assay system. Incubation with monoclonal antibody against alpha 2-antiplasmin increased the Coaset t-PA activity in a concentration-dependent manner, linearly up to 2 micrograms/ml (final) of the antibody, irrespective of the extra acidification, the maximal rise being 41.5% and 19.7% in an in-house and commercial plasma pools respectively. In contrast to alpha 2-antiplasmin antibody, monoclonal antibody against scu-PA decreased the Coaset t-PA activity in the in-house and commercial plasma pools again in a concentration-related manner demonstrating that scu-PA in addition to t-PA was being measured by this method. Incubation with an irrelevant antibody (anti-DNA monoclonal antibody) did not affect the Coaset t-PA values. The mean Coaset t-PA activity of 40 subjects decreased from 1.76 +/- 0.10 (mean +/- SEM) to 0.73 +/- 0.07 when incubated with 8 micrograms/ml (final) monoclonal antibody against scu-PA (P < 0.001). The 't-PA' activity in the absence of scu-PA antibody correlated with the u-PA antigen (r = 0.53; n = 40; P < 0.001), and the activity in the presence of scu-PA antibody correlated with the t-PA activity measured by the bio-functional immunosorbent assay (r = 0.86; n = 40; P < 0.001). Hence, unless the Coaset t-PA activity is measured with appropriate amounts of antibodies to alpha 2-antiplasmin and scu-PA, it is best to qualify the activity measured by this method as being that of total plasminogen activators.
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PMID:Interference of an activity assay of tissue-type plasminogen activator in human plasma by endogenous factors. 884 3

Phenotyping of cytokeratin (CK)18-positive cells in bone marrow is gaining increasing importance for future prognostic screening of carcinoma patients. Urokinase-type plasminogen activator receptor (uPA-R) is one example of a potential aggressive marker for those cells. However, a valid and reliable double staining method is needed. Using monoclonal antibodies against uPA-R and CK18, we modified an immunogold/alkaline phosphatase double staining protocol. UPA-R/CK18-positive tumor cell controls exhibited black uPA-R staining in 15-80% of cases and red CK18 staining in almost 100% of tumor cells. Isotype- and cross-matched controls were completely negative. Bone marrow from healthy donors was always CK18-negative. Reproducibility of CK18-positive cell detection was estimated in a series of specimens from 61 gastric cancer patients comparatively stained with the single alkaline phosphatase-anti-alkaline phosphatase (APAAP) and our double staining method (10(6) bone marrow cells/patient). In four cases, double staining could not reproduce CK18-positive cells. In 34 cases it revealed fewer or equal numbers, and in 23 cases more CK18-positive cells than the APAAP method. Overall quantitative analysis of detected cell numbers (838 in APAAP, range 1-280 in 10(6); double staining 808, range 0-253) demonstrated relative reproducibility of APAAP results by double staining of 97%. Correlation of results between both methods was significant (p < 0.001, linear regression). Sensitivity of double staining tested in logarithmic tumor cell dilutions was one CK18-positive cell in 300,000. Specific uPA-R staining was seen on CK18-positive cells in bone marrow from 29 of 61 patients, and also on single surrounding bone marrow cells. To test the specificity of this staining, bone marrow cytospins from 10 patients without tumor disease were stained for uPA-R with the APAAP method. uPA-R expression was confirmed in all 10 cases, with a mean of 6.5% uPA-R-positive cells in 1000 bone marrow cells (SEM 1.2%). These results suggest that our double staining protocol is a sensitive, reproducible, and specific method for routine uPA-R phenotyping of disseminated CK18-positive cells in bone marrow of carcinoma patients.
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PMID:Immunocytochemical phenotyping of disseminated tumor cells in bone marrow by uPA receptor and CK18: investigation of sensitivity and specificity of an immunogold/alkaline phosphatase double staining protocol. 901 10

Matrix metalloproteinase-3 (MMP-3, or stromelysin-1) specifically hydrolyzes the Glu143-Leu144 peptide bond in 45-kDa single-chain urokinase-type plasminogen activator (scu-PA) and in its two-chain (tcu-PA) derivative, yielding a 17-kDa NH2-terminal domain comprising the u-PA receptor (u-PAR) binding site and a 32-kDa COOH-terminal moiety containing the serine proteinase domain of u-PA. The conversion is completely abolished in the presence of the MMP inhibitors EDTA or 1,10-phenanthroline. Biospecific interaction analysis indicates that binding of MMP-3 occurs through the 32-kDa fragment. The 32-kDa fragment derived from scu-PA (scu-PA-32k) has a specific activity of </=500 IU/mg, but it can be activated with plasmin to a two-chain derivative (tcu-PA-32k) with a specific activity of 79 000 IU/mg. tcu-PA and tcu-PA-32k moieties derived from scu-PA-32k by plasmin or from tcu-PA by MMP-3 have comparable amidolytic activities toward the chromogenic substrate S-2444 (kcat/Km of 110 and 160 mM-1 s-1, respectively) and similar plasminogen activating activities in a coupled chromogenic substrate assay. Specific binding of the 17-kDa NH2-terminal domain to THP-1 monocytoid cells is completely abolished by competition with scu-PA but is not affected by scu-PA-32k (residual binding of 88 +/- 9% (mean +/- SEM; n = 3) with 25-fold molar excess). Thus, MMP-3 removes a functional NH2-terminal u-PAR-binding domain from u-PA without affecting its enzymatic properties.
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PMID:Proteolytic cleavage of urokinase-type plasminogen activator by stromelysin-1 (MMP-3). 958 35


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