Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Coagulation findings were examined in 55 cases of neonatal intracranial hemorrhages (ICH). Marked decreases of the platelet count, fibrinogen, factor XIII (F XIII) activity, were observed in these cases. However, the relatively mild increases in the alpha 2-plasmin inhibitor activity, alpha 2-plasmin inhibitor.plasmin complex and fibrin/fibrinogen degradation products level were observed and only about one third of the cases showed abnormal values. In consideration of these coagulation findings, fifty-eight cases of premature infants were randomly divided into a treated group with a F XIII concentrate and a non-treated group. Thirty cases were administered within 6 hours after delivery to investigate the preventive effects against intraventricular hemorrhages (IVH). Compared in frequencies between both groups limited to the cases with a high risk of IVH, the frequency in the treated group was two out of 13 (15.4%), significantly low (p less than 0.05), while it was six out of eight cases (75.0%) in the non-treated group. From these results it was concluded that a F XIII concentrate is effective in the prophylaxis of IVH in premature infants.
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PMID:Blood coagulation findings and the efficacy of factor XIII concentrate in premature infants with intracranial hemorrhages. 233 68

We studied the disaggregation of human platelets by tissue-type plasminogen activator (t-PA). When added to a suspension of human platelets induced to aggregate in plasma with adenosine 5'-diphosphate, t-PA promoted disaggregation of platelets over several minutes. Addition of fresh plasma or purified human fibrinogen to disaggregated platelets facilitated (reversible) aggregation and subsequent disaggregation. Aspirin treatment of platelets markedly potentiated the ability of t-PA to induce disaggregation. Disaggregation was inhibited by alpha-2-antiplasmin. Comparative analysis of the rate of proteolysis of platelet-bound fibrinogen with that of ambient plasma fibrinogen suggested that fibrinogenolysis of cohesive fibrinogen occurred more rapidly than fibrinogenolysis of ambient fibrinogen. These data demonstrate that t-PA facilitates platelet disaggregation in plasma through kinetically selective proteolysis of cohesive fibrinogen by plasmin, and suggest that thrombolytic mechanisms may serve both to remove platelets from platelet-fibrin thrombi and to disperse circulating platelet aggregates.
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PMID:Tissue plasminogen activator promotes platelet disaggregation in plasma. 243 5

Two monoclonal antibodies against plasminogen and two against alpha-2-antiplasmin were characterized regarding their binding properties towards their respective native and modified antigens and towards the plasmin-alpha-2-antiplasmin complex. Using an ELISA system, the two monoclonal antibodies against plasminogen (MPW1PG, MPW2PG), reacted equally well with purified Glu-plasminogen; binding of one (MPW1PG) to the purified plasmin-alpha-2-antiplasmin complex was, however, more than three orders of magnitude weaker than that of the other. Similarly, both antibodies against alpha-2-antiplasmin (MPW2AP, MPW3AP) reacted equally well with native alpha-2-antiplasmin but binding of MPW3AP to the plasmin-alpha-2-antiplasmin complexes was more than one order of magnitude weaker than that of the other. These results were confirmed by immunoblotting by which it was made evident that the antiplasminogen antibody MPW1PG reacted only with the free or complexed Glu-form of plasminogen or plasmin, while MPW2PG reacted equally well with the Glu- and Lys-form. The alpha-2-antiplasmin antibody MPW2AP reacted with native and complexed alpha-2-antiplasmin while MPW3AP reacted only with the native antigen and with a 8,000 dalton cleavage product of the complex.
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PMID:Monoclonal antibodies against plasminogen and alpha-2-antiplasmin: binding to native and modified antigens. 243

The plasma clearance of neutrophil elastase, plasmin, and their complexes with human inter-alpha-trypsin inhibitor (I alpha I) was examined in mice, and the distribution of the proteinases among the plasma proteinase inhibitors was quantified in mixtures of purified inhibitors, in human or murine plasma, and in murine plasma following injection of purified proteins. The results demonstrate that I alpha I acts as a shuttle by transferring proteinases to other plasma proteinase inhibitors for clearance, and that I alpha I modulates the distribution of proteinase among inhibitors. The clearance of I alpha I-elastase involved transfer of proteinase to alpha 2-macroglobulin and alpha 1-proteinase inhibitor. The partition of elastase between these inhibitors was altered by I alpha I to favor formation of alpha 2-macroglobulin-elastase complexes. The clearance of I alpha I-plasmin involved transfer of plasmin to alpha 2-macroglobulin and alpha 2-plasmin inhibitor. Results of distribution studies suggest that plasmin binds to endothelium in vivo and reacts with I alpha I before transfer to alpha 2-macroglobulin and alpha 2-plasmin inhibitor. Evidence for this sequence of events includes observations that plasmin in complex with I alpha I cleared faster than free plasmin, that plasma obtained after injection of plasmin contained a complex identified as I alpha I-plasmin, and that a murine I alpha I-plasmin complex remained intact following injection into mice. Plasmin initially in complex with I alpha I more readily associated with alpha 2-plasmin inhibitor than did free plasmin.
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PMID:The role of inter-alpha-trypsin inhibitor and other proteinase inhibitors in the plasma clearance of neutrophil elastase and plasmin. 244 91

Oxidative inactivation of alpha-1-proteinase inhibitor (A1-P1) and plasminogen activator inhibitor-1 (PAI-1), both members of the serine protease inhibitor (serpin) superfamily, using mild oxidation conditions has been already demonstrated. The oxidation mechanism has been shown to involve conversion of methionine to methionine sulfoxide in the reactive center of the inhibitors. In this study evidence is presented that alpha-2-antiplasmin (A2-PI) and antithrombin III (AT III) can also be inactivated by means of oxidation. For total inactivation of 50 pM A1-PI about 10 nM chloramine T (CT) and for the same molar concentration of A2-PI and AT III about 250 nM CT were found necessary. C1-inhibitor (C1-INH) showed some resistance to oxidation that could be overcome only by increasing CT to an amount (greater than 2000 nM) already beginning to inactivate the corresponding C1-esterase. As target enzymes for A2-PI, AT III, and A1-PI plasmin, thrombin and elastase, respectively, were used. Their activity was not impaired by the oxidation conditions applied. As there is no methionine in the reactive center of AT III an additional mechanism for oxidative inactivation of serpins has to be taken into consideration. Oxidation seems to be a general mechanism for altering the balances between serine proteases and their inhibitors in favour of the protease.
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PMID:Oxidative inactivation of purified human alpha-2-antiplasmin, antithrombin III, and C1-inhibitor. 245 61

Although the proteinase inhibitor alpha-2-antiplasmin (alpha 2AP) is known to control the activity of plasmin through rapid formation of stable complexes, it also efficiently inactivates chymotrypsin. These interactions are shown to occur at adjacent, overlapping sites so that plasmin attacks the inhibitor at an Arg364-Met365 peptide bond, while chymotrypsin interacts at a Met365-Ser366 sequence one residue downstream. Thus, a naturally occurring plasma serine proteinase inhibitor can have multiple specificities through interactions at adjacent sites. It also illustrates the potential flexibility of the reactive site loop in this class of inhibitors.
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PMID:Alpha-2-antiplasmin: a serpin with two separate but overlapping reactive sites. 245 16

Plasmin-alpha 2-plasmin inhibitor (alpha 2PI) complex, an indicator of in vivo plasmin generation, was measured in the plasma of 48 patients with disseminated intravascular coagulation (DIC), by enzyme-linked immunosorbent assay (ELISA). Plasmin-alpha 2PI complex was markedly elevated to 7.9 +/- 4.26 mg/liter (mean +/- SD) in DIC at presentation, with normal values at less than 0.8 mg/liter. The concentration of plasmin-alpha 2PI complex changed in parallel with the course of DIC and decreased to 1.9 +/- 1.49 mg/liter (n = 28) in remission. Among various underlying disorders, DIC, in patients with acute promyelocytic leukemia, had the highest complex levels (mean 10.8 mg/liter), and septic patients had the lowest levels (mean 3.4 mg/liter). No significant correlation was found between FDP and plasmin-alpha 2PI complex. These results indicate that the quantitative assay of plasmin-alpha 2PI complex in plasma would be valuable in the assessment of hyperfibrinolysis in DIC.
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PMID:Plasmin-alpha 2-plasmin inhibitor complex in plasma of patients with disseminated intravascular coagulation. 245 7

To evaluate the effect of endotoxin on the fibrinolytic response, we administered Escherichia coli endotoxin (4 ng per kilogram of body weight) intravenously to 19 healthy volunteers and measured fibrinolytic proteins, protease inhibitors, neutrophil elastase, and von Willebrand factor in serial blood samples obtained over 24 hours. One hour after endotoxin administration, the level of tissue plasminogen activator (t-PA) antigen rose from 10 to 23 ng per milliliter, peaking at 52 ng per milliliter at three hours. The level of alpha 2-plasmin inhibitor-plasmin complexes increased sevenfold, peaking at three hours. Plasminogen-activator inhibitor-1 activity rose more slowly, from 7 U per milliliter to a maximum of 49 U per milliliter at five hours. The concentrations of neutrophil elastase and von Willebrand antigen were unchanged at one hour, increased approximately threefold by 3 hours, and remained elevated at 24 hours. None of these measures changed in a control group (n = 5) given intravenous saline instead of endotoxin. We studied t-PA functional activity in four subjects. The level of activity rose rapidly, from 1.2 ng per milliliter at base line to 8.3 ng per milliliter at one hour and 13.9 ng per milliliter at two hours; it was undetectable at three hours. This increase in plasminogen activator activity was abolished in vitro by incubation of t-PA with an antiserum specific for human t-PA, suggesting that t-PA may be directly responsible for plasmin generation in the response to endotoxin. We conclude from this study of healthy subjects that endotoxin activates the fibrinolytic system, beginning with release of t-PA in the blood within one hour. The early activation of plasmin by endotoxin may prevent thrombosis, and the increase in fibrinolysis is then offset by the release of plasminogen activator inhibitor.
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PMID:Promotion and subsequent inhibition of plasminogen activation after administration of intravenous endotoxin to normal subjects. 278 17

A monoclonal antibody (MoAb) to alpha 2-plasmin inhibitor designated JTPI-1 inhibited antiplasmin activity by interfering with formation of alpha 2-plasmin inhibitor (alpha 2-PI)-plasmin complex. With this MoAb, we observed plasma clot lysis in vitro and evaluated the potential of JTPI-1 to serve as a new therapeutic agent for thrombolysis. After adding 125I-labeled fibrinogen to plasma, clots were made by adding thrombin and calcium and were then resuspended in normal plasma containing various concentrations of JTPI-1. The presence of JTPI-1 enhanced release of the soluble 125I-labeled fibrin degradation fragment from the clots in a dose-dependent manner. With tissue plasminogen activator (t-PA)-depleted plasma, we showed that induction of clot lysis by JTPI-1 was dependent on fibrin-bound endogenous t-PA. Regulation of fibrinolysis initiated on the fibrin surface by fibrin-bound t-PA and plasminogen is mediated by alpha 2-PI cross-linked to fibrin by activated factor XIII. JTPI-1 bound to this cross-linked alpha 2-PI neutralized its activity and induced partial digestion of fibrin by plasmin. This resulted in additional binding of Glu-plasminogen to fibrin during the incubation. When 1.2 mumol/L JTPI-1 and 5 U/mL exogenous t-PA were present in the suspending plasma, the rate of clot lysis was essentially the same as that induced by 60 U/mL exogenous t-PA alone. These results suggest that JTPI-1 may be useful in reducing the amount of t-PA administered for thrombolytic therapy.
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PMID:Clot lysis induced by a monoclonal antibody against alpha 2-plasmin inhibitor. 251 Aug 36

Levels of the plasmin-alpha 2-plasmin inhibitor complex (PLN-A2PI complex) and alpha 2-plasmin inhibitor (A2PI) were determined by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies in 59 patients with 66 chronic subdural hematomas (SDH's). Normal concentrations of the PLN-A2PI complex and A2PI in plasma are below 0.8 microgram/ml and 60.5 +/- 16.1 micrograms/ml, respectively (mean +/- 2 standard deviations). The hematoma fluid contained high concentrations of the PLN-A2PI complex (4.58 +/- 2.60 micrograms/ml) and low concentrations of A2PI (10.32 +/- 4.81 micrograms/ml), while both values in the plasma of 12 patients with chronic SDH's were within the normal range. This represents local hyperfibrinolytic activity in the hematoma. Stuporous or comatose patients had higher PLN-A2PI complex levels than did the alert and the drowsy or disoriented patients. The layering type of hematoma as seen on computerized tomography scans showed the highest PLN-A2PI complex levels among five types of hematoma. In the fluid drained postoperatively from the subdural cavities of chronic SDH's, both the PLN-A2PI complex and A2PI levels decreased gradually in healing cases. In two patients with hematoma reaccumulation after surgery, both levels increased. The postoperative increase of the PLN-A2PI complex represents the recurrence of intermittent cycles of fibrinolysis, bleeding, coagulation, and hemostasis in the subdural space.
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PMID:Plasmin-alpha 2-plasmin inhibitor complex and alpha 2-plasmin inhibitor in chronic subdural hematoma. 252 Dec 47


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