Thrombolysis with Streptokinase in Rabbits Dose Response, Fibrin-clot Specificity and Laboratory Evaluation of Fibrinolytic Effect

1974 ◽  
Vol 31 (02) ◽  
pp. 265-272
Author(s):  
Andrzej Nowak ◽  
Victor Gurewich

SummaryAn animal model was used in which venous thromboemboli of reproducible size could be formed. The effects of SK 500–50,000 units per hour were evaluated and compared to those of saline. Proportionately the greatest clot lysis occurred with the lowest doses of SK. In contrast to thrombolysis, significant fibrinogenolysis did not occur in any of the animals indicating a high degree of specificity of SK-induced activator for rabbit fibrin. An excellent correlation between the concentration of fibrin degradation products (fdp) measured by the serial dilution protamine sulfate test and the extent of clot lysis was found suggesting this to be a useful method for monitoring the effects of thrombolytic therapy. A method for the laboratory distinction of fdp from fibrin monomer was demonstrated.

1987 ◽  
Author(s):  
P Declerck ◽  
P Mombaerts ◽  
P Holvoet ◽  
D Collen

Plasma levels of crosslinked fibrin degradation products (XLDP) were measured before and at the end of the administration of rt-PA (40 to 100 mg over 1.5 to 8 hours) in healthy volunteers (n=5) and patients with deep venous thrombosis (DVT) (n=8), pulmonary embolism (PE) (n=16)and myocardial infarction(MI)(n=10). Determinations were performed using our newly developed ELISA, specific for crosslinked fibrin derivatives, based on two monoclonal antibodies (15C5 and 8D3H2) raised against purified human fragment D-dimer. All plasma samples were collected on citrate and trasylol. Results are expressed as mean and range of D-dimer equivalents (μg/ml).Baseline levels in patients with MI are only slightly elevated. The increased levels inDVT and PE are in agreement with previous studies. After infusion of rt-PA a small increase of XLDP is seen even innormal subjects. A very marked increasof XLDP is detected in patients with PE and DVT but not in patients with MI. This may reflect differences in the amounts of fibrin clot dissolved in these patient groups.No significant correlation was found between the increase of XLDP and success of therapy, although a significant difference in D-dimer levels was formed between the two groups with PE: successful (n=ll): 116 (range 61-192) vs. unsuccessful (n=5): 68 (36-155).Thus, XLDP are already elevated under baseline conditions in patients with DVT and PE and increase very markedly during thrombolytic therapy. The absolute levels after thrombolytic therapy do not strictly correlate with success of therapy. It could be useful to measure D-dimer levels during early stages of therapy, because the rate of increase of XLDP levels might correlate with the efficacy of thrombolytic treatment.


Blood ◽  
1999 ◽  
Vol 94 (8) ◽  
pp. 2735-2743 ◽  
Author(s):  
Petr Klement ◽  
Peng Liao ◽  
Laszlo Bajzar

Achieving early, complete, and sustained reperfusion after acute myocardial infarction does not occur in approximately 50% of patients, even with the most potent established thrombolytic therapy. Bleeding is observed with increased concentrations of thrombolytics as well as with adjunctive antithrombotic and antiplatelet agents. A novel approach to enhance thrombolytic therapy is to inhibit the activated form of thrombin-activatable fibrinolysis inhibitor (TAFI), which attenuates fibrinolysis in clots formed from human plasma. Identification of TAFI in rabbit plasma facilitated the development of a rabbit arterial thrombolysis model to compare the thrombolytic efficacy of tissue-plasminogen activator (tPA) alone or with an inhibitor, isolated from the potato tuber (PTI), of activated TAFI (TAFIa). Efficacy was assessed by determining the time to patency, the time the vessel remained patent, the maximal blood flow achieved during therapy, the percentage of the original thrombus, which lysed, the percentage change in clot weight, the net clot accreted, and the release of radioactive fibrin degradation products into the circulation. The results indicate that coadministration of PTI and tPA significantly improved tPA-induced thrombolysis without adversely affecting blood pressure, activated partial thromboplastin time, thrombin clotting time, fibrinogen, or -2-antiplasmin concentrations. The data indicate that inhibitors of TAFIa may comprise novel and very effective adjuncts to tPA and improve thrombolytic therapy to achieve both clot lysis and vessel patency.


1975 ◽  
Author(s):  
M. Kazama ◽  
T. Abe

1) Fresh citrated plasmas of cases of defibrination syndrome were chromatographed on Biogel A-5 m column, which revealed a two-peaked elution profile of fibrinogen-related antigen with reproducibility. The first peak was eluted at the Vo of the column and the second one at Ve of the early FDP. It was found in the preliminary experiments in vitro, that the big molecular FDP was formed exclusively in the process of fibrin clot lysis, irrespective if it was non-stabilized or stabilized.2) FDP in thesen patients’ serums, after thorough digestion with plasmin, were chromatographed on Sephadex G200 column. A reproducible elution profile of FDP-D antigen revealed single peak, of which Ve was corresponded with that of FDP-D monomer derived from fibrinogen or non-stabilized fibrin.It was postulated that the FDP in plasmas of defibrination syndrome were mainly originated from the fibrinogen or non-stabilized fibrin formed in the process of the diseases.


1990 ◽  
Vol 63 (01) ◽  
pp. 076-081 ◽  
Author(s):  
Pascale Gaussem ◽  
Sophie Gandrille ◽  
Pascale Molho-Sabatier ◽  
Loïc Capron ◽  
Jean-Noël Fiessinger ◽  
...  

SummaryUsing a monoclonal antibody-based assay, we measured the fibrin degradation product release in the supernatant of plasma clots obtained before and after venous occlusion (VO) in 30 patients with definite or suspected vascular thrombosis (19 definite and 2 suspected deep vein thrombosis, 6 recurrent superficial thrombophlebitis, 3 arterial occlusions of lower limbs). tPA and PAI-1 concentrations were determined using ELISA assays; the post-occlusion values were corrected for haemoconcentration. The increase in tPA during VO was correlated with haemoconcentration (r = 0.74), but 3 patients had ineffective VO (<2% increase in proteins). The fibrinolytic response to VO was evaluated using the shortening of the time necessary for the release of 200 μg of fibrin degradation products per mg of fibrinogen (Δ T 200). Two among the 27 patients with effective VO were bad responders with a Δ T 200 <3 h (whereas all the others had Δ T 200 >10 h). These patients had respectively a deficient tPA release (Δ tPA = 1 ng/ml) and an elevated PAI-1 level at rest (33 ng/ml). Several other patients were bad responders in terms of tPA release or of shortening of the euglobulin clot lysis time but they had a normal Δ T 200. This plasma clot test reflects the ability of free tPA to bind to fibrin (the amount of which depends on the level of tPA and PAI-1), and may be useful in the diagnosis of a hypofibrinolytic state.


1987 ◽  
Author(s):  
P J Gaffney ◽  
L J Creighton ◽  
A Curry ◽  
B MacMahon ◽  
R Thorpe

Monoclonal antibodies (mabs) to crosslinked fibrin degradation products (XL-FDP) having the general formula D/Y[X]nY/D (known as X-oligomer) and D-D (known as D dimer) have been raised in balb/C mice by both a novel mtrasplenic and a conventional subcutaneous route of immunisation and by combinations of both these procedures. Mabs to X-oligomers (NIBn 52 and NIBn 123) obtained by an intrasplenic procedure have been demonstrated to crossreact only with X-oligomer in a 2-site ELISA procedure and not with D dimer or whole fibrinogen and have been shown to be of value m the examination of clinical material obtained from patients with various types of thrombosis and have also been useful in monitoring the efficacy of thrombolytic therapy. The X-oligomer mabs are immunoglobulins of the M class. It was demonstrated that their unique specificity for conformational epitopes on the large X-oligomer fragments does not reside in the IgM structure since alterative immunisation procedures have been used to generate mabs of the IgG class which have the same specificity. Using immunoglobulin class switching in culture rather than during immunisation was suggested by certain cell lines which produced both IgM and IgG specific for X-oligomer. This latter point needs rigorous validation.Immunoglobulin G type mabs to highly purified D dimer were raised by conventional subcutaneous immunisation of balb/C mice. One of these, NIBn-11, was found to crossreact with PVC-immobilised X-oligomer and D dimer but not with fibrinogen. However NIBn-11 did not bind to D dimer in a 2-site ELISA procedure while crossreactmg quite avidly with X-oligomer. This suggests that the D dimer epitope to which NIBn-11 is directed is expressed in some conformations and not m others and that these conformations are always expressed in the complex X-oligomer group of fragments. These mabs, whilst of value in measuring certain unique fibrin fragments m plasma, are useful in the epitope mapping of fibrinogen/fibrin and their plasmm-mediated


1987 ◽  
Vol 62 (4) ◽  
pp. 1416-1421 ◽  
Author(s):  
E. W. Ferguson ◽  
L. L. Bernier ◽  
G. R. Banta ◽  
J. Yu-Yahiro ◽  
E. B. Schoomaker

Sixty healthy men in three physical fitness categories (sedentary, on no organized fitness program; joggers, running 5–15 miles/wk; and marathoners, running greater than 50 miles/wk) were evaluated for changes in blood clotting and fibrinolytic activity before and after maximum exercise on a treadmill according to the Bruce protocol. The rate of blood clotting, as measured by prothrombin times, partial thromboplastin times and thrombin times, was accelerated by exercise (all P less than 0.005). The ability of euglobulin clots and plasma clots to lyse incorporated 125I-fibrin, termed 125I-euglobulin clot lysis (IEL) and 125I-plasma clot lysis (IPCL), were used as indexes of fibrinolytic activity. Marathoners had greater increases in fibrinolytic activity with exercise (76% compared with 63% for joggers and 55% for sedentary subjects by IEL; 427% compared with 418% for joggers and 309% for sedentary subjects by IPCL; all P less than 0.05). Fibrin degradation products increased with exercise (P less than 0.005 for the total group of 60 subjects). The absolute concentrations of alpha 2-plasmin inhibitor, alpha 2-macroglobulin, and antithrombin III increased with exercise (all P less than 0.005), but when concentrations were corrected for acute shifts of plasma water during exercise, the quantity of these inhibitors actually decreased (all P less than 0.005). The changes in clotting assays with exercise were not significantly correlated with changes in whole blood lactate, blood pyruvate, or rectal temperatures. Fibrinolytic assays before and after exercise correlated poorly to moderately with blood lactates (IEL: r = 0.441 and r = 0.425, respectively; IPCL: r = 0.294 and r = 0.544, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)


Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1341-1348 ◽  
Author(s):  
CM Lawler ◽  
EG Bovill ◽  
DC Stump ◽  
DJ Collen ◽  
KG Mann ◽  
...  

Abstract The validity of markers in plasma of in vitro thrombolysis was investigated in 12 patients with extensive fibrinogen breakdown (greater than 80%, group 1) and in 12 patients with minimal breakdown (less than 20%, group 2). The patients were treated with 100 mg of recombinant tissue-type plasminogen activator (rt-PA) in the “Thrombolysis in Myocardial Infarction II” (TIMI II) trial. Cross- linked fibrin degradation product levels were measured with two variant enzyme-linked immunosorbent assays (ELISAs), both using a fibrin fragment D-dimer specific capture antibody. In one instance, a tag antibody was used that cross-reacts with fibrinogen (pan-specific tag ELISA); in the other, the tag antibody was specific for fibrin fragment D (fibrin-specific tag ELISA). Apparent concentrations of cross-linked fibrin degradation products at baseline were within normal limits with both assays in most patients. At 8 hours after rt-PA infusion, the measured cross-linked fibrin degradation products were increased about twofold to fourfold in group 2 with both assays. However, in group 1, levels were significantly higher with the pan-specific tag ELISA (5.8 +/- 4.2 micrograms/mL) compared with the fibrin-specific tag ELISA (1.5 +/- 1.3 micrograms/mL). This observation was most likely a result of detection of fibrinogen degradation products in the pan-specific ELISA. Apparent levels of fibrinopeptide B beta 1–42, a marker of fragment X formation, increased during thrombolysis from 4.2 +/- 2.8 pmol/mL to 2,000 +/- 230 pmol/mL in group 1 and from 4.1 +/- 2.1 pmol/mL to 300 +/- 43 pmol/mL in group 2, and were correlated significantly with the extent of fibrinogen breakdown (r = -0.8). Fibrinopeptide beta 15–42 levels increased from 4.3 +/- 3 pmol/mL to 70 +/- 19 pmol/mL in group 1, but did not increase in group 2. The apparent increase in group 1 could be explained by cross-reactivity of fibrinopeptide B beta 1–42 in the fibrinopeptide beta 15–42 assay. We conclude that cross-linked fibrin degradation product levels as measured with a pan-specific tag ELISA and fibrinopeptide beta 15–42 levels as measured with certain monoclonal antibody-based ELISA are influenced by the extent of fibrinogen degradation. Fibrinopeptide B beta 1–42 is a marker specific for fibrinogen breakdown. Cross-linked fibrin degradation product levels, measured with a fibrin-specific tag ELISA, appear to be markers specific for thrombolysis. Consequently, assays similar to the fibrin- specific tag ELISA may provide more accurate information when correlated with clinical endpoints.


1977 ◽  
Author(s):  
F.N. McKenzie ◽  
W. Wall ◽  
R.O. Heimbecker ◽  
R. Barr ◽  
A. Robert

Reinfusion of blood shed during elective or emergency vascular surgery (autotransfusion) is an under utilized technique. This is due in part to doubts as to the quality of autotransfused blood and concern about the risk of inducing a coagulopathy in the recipient. We have measured coagulation and hematologic parameters in autotransfused blood in the recipient before and at intervals after operation in 62 patients, none of whom received bank blood or blood products at the time of the study. The patients were heparinized (3 mg/Kg) during operation and this was reversed by protamine at the end of the procedure. The salvaged blood was reinfused immediately after appropriate samples had been taken. The mean volume of blood autotransfused was 1.8L in 58 patients and 9.4L in 4 patients. There was excellent preservation of platelets and fibrinogen, normal levels being maintained both in the autotransfused blood and in the recipients. Values for fibrin degradation products and euglobulin clot lysis remained normal. The mean plasma hemoglobin in the autotransfused blood was 416 mg% and this was not correlated to the volume autotransfused. Partial thromboplastin time which was prolonged by heparin during surgery was consistently normal post-operatively. No patient developed complications which could be attributed to autotransfusion and, in particular, re-operation for post-operative bleeding was never required and wound hematoma was not seen. We conclude that autologous blood may be returned to patients in large amounts without significant risk using the technique described. The technique deserves wider application in major surgery.


Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1189-1192 ◽  
Author(s):  
NJ de Fouw ◽  
F Haverkate ◽  
RM Bertina ◽  
J Koopman ◽  
A van Wijngaarden ◽  
...  

Abstract The effect of purified human activated protein C (APC) and protein S on fibrinolysis was studied by using an in vitro blood clot lysis technique. Blood clots were formed from citrated blood (supplemented with 125I-fibrinogen) by adding thrombin and Ca2+-ions; lysis of the clots was achieved by adding tissue-type plasminogen activator. The release of labeled fibrin degradation products from the clots into the supernatant was followed in time. We clearly demonstrated that APC accelerates whole blood clot lysis in vitro. The effect of APC was completely quenched by antiprotein C IgG, pretreatment of APC with diisopropylfluorophosphate, and preincubation of the blood with antiprotein S IgG. This demonstrates that both the active site of APC and the presence of the cofactor, protein S, are essential for the expression of the profibrinolytic properties. At present, the substrate of APC involved in the regulation of fibrinolysis is not yet known. Analysis of the radiolabeled fibrin degradation products demonstrated that APC had no effect on the fibrin cross-linking capacity of factor XIII.


2003 ◽  
Vol 90 (09) ◽  
pp. 414-421 ◽  
Author(s):  
Chengliang Wu ◽  
Ningzheng Dong ◽  
Valdeci da Cunha ◽  
Baby Martin-McNulty ◽  
Katherine Tran ◽  
...  

SummaryStudies have shown that inhibition of TAFI by small peptides enhances pharmacological effects of tPA in animal models of thrombosis, suggesting that TAFI modulates the fibrinolytic system. In this study, we investigated the effect of activated human TAFI (TAFIa) on endogenous fibrinolysis in a rat model of intravascular fibrin deposition. 125I-labeled fibrinogen was injected intravenously followed by a bolus injection of batroxo-bin, a thrombin-like enzyme. Batroxobin cleaved fibrinogen to form insoluble fibrin that was deposited in tissues, including the lungs. This was shown by a decrease of radioactivity in the blood as a result of consumption of 125I-labeled fibrinogen and an elevation of radioactivity in the lungs 5 min following batroxobin administration. Endogenous fibrinolysis was detected by a gradual increase in radioactivity in the blood and a decrease in radioactivity in the lungs at 30 min, an indication of radio-labeled fibrin degradation products (FDPs) being released into the circulation from the tissues. Intravenous administration of human TAFIa dose-dependently attenuated the later phase reduction of radioactivity in the lungs. When the dose of TAFIa was 218 μg/kg, giving a peak plasma level of TAFIa 0.9 ± 0.05 μg/ml, the spontaneous fibrinolysis was completely prevented. These results provide direct evidence that an increase in circulating TAFIa impairs endogenous clot lysis in a rat model of fibrin deposition.


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