bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Effects of Urokinase — Prevention by Different Inhibitors
Authors: Oethinger M D , Seifried E 
Published: July 2018

SummaryThe present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activato(u-PA, urokinase) on normal citrated plasma. When 10 μg/ml u-PA wereadded to pooled normal plasma and incubated for 30 min at an ambient temperature (25° C), α2-antiplas-min decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control,whereas α2-antiplasmin was fully consumed at 37° C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25° C. Thrombin time prolonged to 190% of control.Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KlU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection ofα2-antiplasmin at therapeutic levels of u-PA.It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.
Heparin Stimulates Fibrinolysis in Mesothelial Cells by Selective lnduction of Tissue-Plasminogen Activator but not Plasminogen Activator Inhibitor-l Synthesis
Authors: Grulich-Henn Jürgen , Preissner Klaus T , Müller-Berghaus Gert 
Published: July 2018

SummaryThe regulation of tissue-plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-l) synthesis was studied in cultured human mesothelial cells derived from omentum (HOMC). Heparin (100 U/ml) as well as pentosan polysulfate (300 pg/mt) stimulated tPA synthesis by HOMC 2.9-4.5-fold. Heparin-induced tPA production was dose- and time-dependent and was inhibited by cycloheximide. tPA production by HOMC was also stimulated by phorbol 12-myristrate l3-acetat (2.6-fold), fibrin clots (1.9-fold), or batroxobin (1.9-fold).Heparin and pentosan polysulfate did not stimulate PAI-1 production by HOMC, while phorbol l2-myristrate 13-acetat (100 nM) increased the concentration of PAI-1 in the conditioned medium by 2.6-fold over 24 h. The interaction of heparin with HOMC was studied by direct binding experiments. Dose-dependent specific binding of biotinylated heparin to HOMC was saturable at about 10 pg/ml, the Kp was estimated to about 0.15 pM. Biotinylated heparin bound rapidly to HOMC and reached a plateau within 60 min. Unlabeled heparin as well as pentosan polysulfate inhibited binding of biotinylated heparin in a dose-dependent fashion. These data demonstrate that heparin interacts with HOMC, and increases the fibrinolytic capacity in these cells by selectively increasing the production of tPA.
A Precise and Rapid Microtitre Plate Clot Lysis Assay: Methodology, Kinetic Modeling and Measurement of Catalytic Constants for Plasminogen Activation during Fibrinolysis
Authors: Jones A J S , Meunier A M 
Published: July 2018

SummaryA rapid and precise turbidimetric clot lysis assay employing a microtitre plate reader and personal computer is described in detail. The use of such widely available instrumentation, the convenience and rapid throughput suggest the assay could be developed as a reference method with which to measure the potency of tissue plasminogen activator (t-PA) in conjunction with the WHO reference preparation. The method has been used to investigate molecular parameters involved in fibrinolysis. Aggregation status of the fibrin does not appear toinfluence the mechanism of plasminogen activation and clot lysis by plasmin. High ratios of plasminogen to fibrin resulted in a change in clot turbidity and in a change in the lysis profile of turbidity versus time. This is probably the result of plasminogen binding to fibrin and consequent restriction of the access of plasmin to its sites of cleavage in the fibrin. A simple model is proposed, and equations have been derived, for the kinetics of lysis which adequately describe the mechanism and which are confirmed by experimental data. This model results in estimates of the Km and kcat for the activation of plasminogen by t-PA during clot lysis of approximately 150 nM and0.1 s-1, respectively, in excellent agreement with published values The assay should therefore prove useful in quantitative evaluationsof the molecular phenomena occurring during fibrinolysis. The more rapid activation of lys-plasminogen than glu-plasminogen by t-PA was confirmed. However, evidence was obtained that the lys-form binds more tightly to fibrin by the same factor. This observation suggested that the appropriate substrate in the kinetic model is fibrin-bound plasminogen. When the data were re-analysed using published values ofthe affinities of the two forms, t-PA was found to activate both forms indistinguishably on the fibrin surface, consistent with suggestions that the conformation of glu-plasminogen changes to one more like that of lys-plasminogen upon binding to fibrin.
The Platelet Count in Carcinoma of the Lung and Colon
Authors: Costantini Vincenzo , Zacharski Leo R , Moritz Thomas E , Edwards Richard L 
Published: July 2018

SummaryPlatelet counts were evaluated in 714 patients with advanced non-small cell lung cancer (N-SCLC), small cell carcinoma of the lung (SCCL), and colon cancer entered to a clinical trial. Patients had not received prior chemotherapy. Platelet counts were not different in patients who had received radiation therapy prior to entry to the study. In comparison to the other tumor types, patients with N-SCLC demonstrated an increased prevalence of thrombocytosis (counts greater than 400,000/mm3), higher platelet counts at the time of entry to the study, higher over all mean platelet counts, relative preservation of high platelet levels during disease progression, and no relationship between platelet numbers and the amount of chemotherapy given. By contrast, platelet counts in patients with SCCL were negatively correlated with the absolute amount of cyclophosphamide and adriamycin given, and declined most dramatically with disease progression and death. Platelet numbers did not correlate with fibrinopep-tide A or fibrin split product levels suggesting that disseminated intravascular coagulation or fibrinolysis may have had less influence on platelet numbers than certain other factors. By contrast, significant correlations were found for all three tumor types between platelet numbers and other indicators of bone marrow function including anemia, total leukocyte count, and absolute neutrophil count; and the fibrinogen level. Based upon these findings, we postulate that the host response to malignancy, possibly in the form of production of bone marrow-stimulating cytokines, may play a prominent role in regulation of platelet counts in these (and perhaps other) neoplasms, and that a particularly prominent and persistent degree of marrow stimulation exists in patients with N-SCLC.
Effects of Fixed Minidose Warfarin on Coagulation and Fibrinolysis Following Major Gynaecological Surgery
Authors: MacCallum P K , Thomson J M , Poller L 
Published: July 2018

SummaryCoagulation and fibrinolytic studies have been performed in patients who were undergoing major gynaecological surgery and randomised to either fixed minidose warfarin (1 mg daily) or matched placebo. With warfarin, a prolongation of the prothrombin time was observed on day 2 which persisted for at least 5 days and was greater than with placebo. The maximal postoperative mean INR was, however, only 1.2 which is considerably less than the target value for prophylaxis of deep vein thrombosis with full dose warfarin. The warfarin group showed two unexpected findings: significantly elevated fibrin specific degradation products throughout the postoperative period compared with placebo and absence of the expected rise of PAI, the major fibrinolytic inhibitor, on the first day after surgery. Levels of fibrinogen degradation products and FI + 2 prothrombin fragments rose significantly and progressively in both groups in the postoperative period. With placebo, FI + 2 showed an apparent higher percentage increase on each post-operative day but the differences between the groups were not significant. Increased fibrinolysis may be one of the mechanisms for the protective action of minidose warfarin in prophylaxis of DVT after major surgery.
Impact of Smoking, Physical Training and Weight Reduction on FVII, PAM and Hemostatic Markers in Sedentary Men
Authors: Gris Jean-Christophe , Schved Jean-François , Feugeas Olivier , Aguilar-Martinez Patricia , Arnaud Anne , Sanchez Nicole , Sarlat Christian 
Published: July 2018

SummaryThe variations of FVII, PAI-1, TAT complexes, fibrinopeptide A, D-Dimers and beta thromboglobulin plasma levels were studied on 30 sedentary men, smokers and non-smokers, who were admitted to a 6 months’ program of physical training and smoking cessation. After 3 months of intervention, sustained physical training was associated with the decrease of FVII and PAI-1 levels. Mild exercise performed during a second 3-month period could maintain normal FVII and PAI-1 activities but participants who stopped the training increased their FVII and PAI-1 plasma levels. FVII was not influenced by smoking habits. Smoking cessation seemed to slightly potentiate the decrease of PAI-1 levels associated with mild exercise. Overweight, FVII and PAI-1 levels were correlated and the weight reduction induced by training was related to the changes in the factors. In smokers, physical exercise was associated with a significant increase of hemostatic markers. This exercise-induced variation disappeared after 3 months of intervention in participants who stopped smoking and reappeared in those who smoked again after 6 months of intervention. This finding was not influenced by the physical training program.
Evaluation of International Normalized Ratios by a Controlled Field Survey with 4 Different Thromboplastin Reagents
Authors: Kazama Mutsuyoshi , Suzuki Setsuko , Abe Takeshi , Tahara Chieko , Shimazu Chisato , Akiyama Yoshiko , Higashi Katsumi , Ishiguro Izumi , Kimura Toshiyuki , Motoi Shigemi , Tsukai Kazuo , Kobayashi Masaki , Niwa Yoshimasa , Makita Hisao , Yasumuro Yoko , Nakatake Toshihiko 
Published: July 2018

SummaryA nationwide survey has been performed in Japan involving 75 laboratories to assess the relative reliability of different methods of reporting prothrombin time results in anticoagulant control. The interchangeability of results using prothrombin time, prothrombin activity percentage, prothrombin ratio and international normalized ratios (INR) were compared with four different thromboplastin reagents and a range of coagulometers. A secondary batch of reference thromboplastin of human brain origin (BCT/454) was used to calibrate the local thromboplastins and for comparison of methods of reporting. The study revealed the closest agreement of the results between BCT and the other reagents, and the regression lines of these reagents were almost identical, when the results were reported as INR. Box-Whisker plot analysis showed that the distribution of the results was large with the more deficient plasmas with all methods of reporting. It was found by this analysis that the interchangeability of the results was greatest when the results were expressed by INR, because the mean values obtained of each plasma using different thromboplastin reagents gave the lowest CV and the frequency of the far-out data was least, compared with the other methods of expression. On the other hand, the type of coagulometer had almost as much effect as the thromboplastin reagent on the prothrombin time, even if INR was used. Interchangeability of INR would be further improved by providing ISI values for each reagent/ instrument combination.
Relationship of Major Histocompatibility Complex Class II Genes to Inhibitor Antibody Formation in Hemophilia A
Authors: Lippert Lloyd E , Fisher Lyman Mc A , Schook Lawrence B 
Published: July 2018

SummaryApproximately 14% of transfused hemophiliacs develop an anti-factor VIII inhibitory antibody which specifically neutralizes factor VIII procoagulant activity. In this study an association of the major histocompatibility complex (MHC) with inhibitor antibody formation was evaluated by restriction fragment length polymorphism (RFLP) analysis using BamHI, EcoRI, HindII, PstI, PvuII and TaqI digested genomic DNA probed with DP beta, DQ alpha, DQ beta and DR beta class II MHC gene probes. The RFLP patterns for 16 non-inhibitor and 11 inhibitor hemophiliac patients were analyzed. These 24 enzyme:probe combinations generated 231 fragments. Fifteen (15) fragments associated with the inhibitor phenotype; odds ratios ranged from 5.1 to 45 and lower bounds of 95% confidence intervals were > 1.000 for all 15 fragments. Five (5) fragments associated with non-inhibitors, with odds ratios ranging from 6.4 to 51.7. This report establishes a MHC related genetic basis for the inhibitor phenotype. No statistically significant differences in the distribution of serologically defined HLA-DR phenotypes were observed between the inhibitor and non-inhibitor groups.
Prevention of Canine Coronary Artery Thrombosis with Echistatin, a Potent Inhibitor of Platelet Aggregation from the Venom of the Viper, Echis carmatus
Authors: Shebuski Ronald J , Ramjit Denise R , Sitko Gary R , Lumma Patricia K , Garsky Victor M 
Published: July 2018

SummaryA model of acute, platelet-dependent canine coronary artery thrombosis was utilized to assess the antithrombotic effect of a synthetic, RGD-containing 49-residue protein termed echistatin. This protein is derived from the venom of the viper, Echis carinatus. In vitro, echistatin inhibited ADP (10 ΜM)-induced platelet aggregation with IC50 values in human and canine platelet-rich plasma of 101 ± 4 and 127 ± 32 nM, respectively. In vivo, in the dog, infusion of echistatin for 30 min at 20 pg kg−1 min−1 or 2.6 nM kg−1 min−1 resulted in total abolition of acute platelet-dependent coronary thrombus formation in all dogs tested (n = 5). Infusion of a lower dose (10 pg kg−1 min−1) was not effective in prevention of thrombus formation. Blood samples were taken before and after infusion of echistatin in order to determine ex vivo platelet aggregatory responses. Echistatin (20 pg kg−1 min−1, i.v.) attenuated ex vivo platelet aggregation elicited by ADP, U-46619 and collagen and increased bleeding time by 2.9 ± 0.5-fold over control. Thus, in the dog, echistatin is an effective antithrombotic agent inhibiting both platelet aggregation in vivo in the coronary artery as well as ex vivo with a concomitant increase in bleeding time. Furthermore, the effects of echistatin on platelet aggregation and bleeding time are reversible with restoration to control levels occurring 30-60 min after termination of the infusion.
Comparative Effects of Proteinase Inhibitors, Plasminogen Antiactivators, Heparin and Acetylsalicylic Acid on the Experimental Disseminated Intravascular Coagulation Induced by Thrombin
Authors: Moriau M , Rodhain J , Noel H , De Beys-Col C , Masure R 
Published: July 2018

SummaryIn an experimental study in the rabbit, the modifications of some haemostasis parameters (platelet count, platelet retention and aggregation, platelet factors 3 and 4, platelet and plasma plasmin inhibiting activities, fibrinogen and other plasma factor levels, FDP), and histological findings are compared in both the normal animal and the animal with disseminated intravascular coagulation (DIC) induced by thrombin perfusion after administration of fibrinolytic inhibitors (plasminogen antiactivators and proteinase inhibitors).In the normal animal, the administration of fibrinolytic inhibitors is followed by haemostatic changes similar to those found in thrombophilic states. The modifications are more pronounced with plasminogen antiactivators than with proteinase inhibitors.In the animal with DIC, the administration of fibrinolytic inhibitors enhances the haemostatic and the biological disorders produced by thrombin perfusion. The effect of the plasminogen antiactivators is even more evident.The preventive administration of heparin reduces or abolishes the biological and histological disorders induced by thrombin; its beneficial effect is considerably reduced when thrombin is combined with fibrinolytic inhibitors.The administration of acetylsalicylic acid appears to be ineffective for the prevention of haemostatic and histological changes induced by thrombin perfusion.
Rapid Detection and Quantitation of Precipitating Streptokinase-Antibodies
Authors: Spöttl F , Kaiser R 
Published: July 2018

SummaryStreptokinase-therapy is regularly followed by a marked increase of precipitating streptokinase-antibodies. These antibodies cause a significant inhibition of streptokinase-induced plasminogen activation. Counterelectrophoresis is a useful method of tracing the antibodies in serum. For quantitative estimation a modified radial immunodiffusion method is presented. The antibodies were identified as IgG.
Clinical Manifestations and Management of Inherited Thrombophilia: Retrospective Analysis and Follow-up after Diagnosis of 238 Patients with Congenital Deficiency of Antithrombin III, Protein C, Protein S
Authors: De Stefano V , Leone G , Mastrangelo S , Tripodi A , Rodeghiero F , Castaman G , Barbui T , Finazzi G , Bizzi B , Mannucci P M 
Published: July 2018

SummaryThe clinical history of 238 patients with inherited thrombophilia (AT III = 94, PC = 103, PS = 41) was analyzed retrospectively at diagnosis and in the follow-up period after diagnosis. At diagnosis 129 patients (54%) had suffered from thrombosis, with a recurrence rate of 48%. The most frequent onset manifestation was deep vein thrombosis of lower limbs (58%). Thrombotic history started before 40 in 80% of the cases. Forty-nine percent of the venous thromboses were preceded by a triggering event, in most cases pregnancy (17%) and surgery (12%). After diagnosis, follow-up lasted a total of 1,113 pt-years. A policy of short-term prophylaxis during risk situations for all patients and long-term prophylaxis in symptomatic patients failed to prevent venous thrombotic episodes (diagnosed by objective methods) in 4 previously asymptomatic subjects and recurrence in 7 previously symptomatic subjects. After knowledge of the patients’ diagnosis the incidence of venous thrombosis/100 pt-years was reduced as compared before diagnosis as total episodes (onset + recurrencies) (1.0 vs 1.9), onset episodes (0.7 vs 1.3) and recurrent episodes (1.3 vs 4.8), even though the differences were not statistically significant. However most of the venous thromboses occurred at a more advanced age (67% after 40 years) and without any apparent cause (83%), at significant variance with the period preceding the diagnosis; in particular the incidence of venous thrombotic onset in patients younger than 40 passed from 1.3/100 pt-years to 0.2/100 pt-years. In 6 recurrences after diagnosis a poor compliance for antithrombotic treatment was recognized. We conclude that a policy based on knowledge of diagnosis and on the implementation of antithrombotic treatment during risk situations appears to modify the clinical outcome of deficiencies of natural anticoagulants even in the absence of long-term antithrombotic prophylaxis; in particular morbidity of young patients is significantly reduced.
Effects of the Synthetic Thrombin Inhibitor Argatroban on Fibrin- or Clot-Incorporated Thrombin: Comparison with Heparin and Recombinant Hirudin
Authors: Berry Christopher N , Girardot Christine , Lecoffreo Catherine , Lunven Catherine 
Published: July 2018

SummaryThe inhibitory effects of argatroban on clot- or fibrin-bound human thrombin were studied using the thrombin-specific chromogenic substrate S2238 (200 μM). These effects were compared to those of recombinant hirudin (rHV2 Lys 47) and the heparin/antithrombin III complex. Argatroban concentration-dependently inhibited the cleavage of S2238 by a thrombin solution, which had been titrated to give the same change in OD405 nm as fibrin-bound thrombin, with an IC50 of 1.1 μM with 90% inhibition at 8 μM. rHV2 Lys 47 and heparin had IC50 values of 1.2 nM and 0.003 U/ml respectively under these conditions. However, when the compounds were tested against fibrin-bound thrombin, argatroban had an IC50 of 2.8 μM with 65% inhibiton at 8 μM, whereas rHV2 Lys 47 had an IC50 of 23 nM (with only 56% inhibition at 200 nM), and heparin had an IC50 of 0.5 α 0.38 U/ml (with only 58% inhibition at 5 U/ml); i. e. the two compounds were 19 and 168 times less active against fibrin-bound thrombin than against thrombin in solution. The differences between the inhibitory effects of the compounds against thrombin bound to a plasma clot were even more striking in that the IC50 of argatroban was increased from 1.1 (vs. thrombin in solution) to 2.7 μM, while, although rHV2 Lys 47 and heparin had IC50 values of 2.8 nM and 0.004 U/ml against thrombin in solution, they had little (32% inhibition by 4 pM rHV2 Lys 47) or no effect (even at 5.0 U/ml heparin) against the amidolytic activity of a plasma clot. We conclude that argatroban could present advantages over hirudin and heparin in the treatment of pathologies where the enzymatic activity of clot-bound thrombin may play a significant role.