Effects of organic extracts and their different fractions of five Bangladeshi plants on in vitro thrombolysis.

BACKGROUND: The increasingly high incidence of ischemic stroke caused by thrombosis of the arterial vessels is one of the major factors that threaten people's health and lives in the world. The present treatments for thrombosis are still unsatisfactory. Herbal preparations have been used since ancient times for the treatment of several diseases. The aim of this study was to investigate whether herbal preparations possess thrombolytic activity or not. METHODS: An in vitro thrombolytic model was used to check the clot lysis effect of the crude extracts and fractions of five Bangladeshi plant viz., Trema orientalis L., Bacopa monnieri L., Capsicum frutescens L., Brassica oleracea L. and Urena sinuata L. using streptokinase as a positive control and water as a negative control. Briefly, venous blood drawn from twenty healthy volunteers was allowed to form clots which were weighed and treated with the test plant materials to disrupt the clots. Weight of clot after and before treatment provided a percentage of clot lysis. RESULTS: Using an in vitro thrombolytic model, different fractions of five Bangladeshi medicinal plants namely T. orientalis, B. monnieri, C. frutescens, B. oleracea and U. sinuata showed various range of clot lysis activity. Chloroform fractions of T. orientalis, B. monnieri, C. frutescens, B. oleracea and U. sinuata showed highest significant (P < 0.05 and P < 0.001) clot lysis activity viz., 46.44 ± 2.44%, 48.39 ± 10.12%, 36.87 ± .27%, 30.24 ± 0.95% and 47.89 ± 6.83% respectively compared with positive control standard streptokinase (80.77 ± 1.12%) and negative control sterile distilled water (5.69 ± 3.09%). Other fractions showed moderate to low clot lysis activity. Order of clot lysis activity was found to be: Streptokinase > Chloroform fractions > Methanol (crude) extract > Hydro-methanol fractions > Ethyl acetate fractions > n-hexane fractions > Water. CONCLUSIONS: Our study suggests that thrombolytic activity of T. orientalis, B. monnieri and U. sinuata could be considered as very promising and beneficial for the Bangladeshi traditional medicine. Lower effects of other extracts might suggest the lack of bio-active components and/or insufficient quantities in the extract. In vivo clot dissolving property and active component(s) of T. orientalis and B. monnieri for clot lysis could lead the plants for their therapeutic uses. However, further work will establish whether or not, chloroform soluble phytochemicals from these plants could be incorporated as a thrombolytic agent for the improvement of the patients suffering from atherothrombotic diseases.

[Effects of streptokinase and hyperbaric oxygen therapy on venous occlusion after limb reimplantation in rats]. / Estreptoquinase e oxigênio hiperbárico em congestão após reimplante de membro.

OBJECTIVE: The effectiveness of streptokinase and hyperbaric oxygen therapy on venous occlusion after limb reimplantation was tested in rats. METHODS: Amputation with preservation of vessels and nerves of the right hind limb was carried out in 140 rats. Groups MG0, MG1, MG2, MG3 and MG4 were submitted to 0, 1, 2, 3 and 4 hours of venous occlusion. MG3 was elected as control for the experimental groups. Groups EG1 and EG2 were submitted to 3 hours of venous occlusion and were treated with streptokinase and hyperbaric oxygen therapy. Limbs were observed for 7 days and their mortality and survival rates were studied. RESULTS: Trans-operatory mortality rates in groups MG0, MG1, MG2, MG3 and MG4 were 0, 10, 15, 30 and 60% respectively and the postoperative mortality rates were 5; 11.1; 11.7; 14.2 and 100% respectively. The limb survival rates were 100%, 87.5%, 80% and 66.67% respectively and 76.9% and 100% in EG1 and EG2. Model groups were statistically different, except for MG1 and MG2 in trans-operatory mortality rates. There were no statistical differences in postoperative mortality rates between model groups except for MG3 and MG4. Model groups were statistically different, with the exception of MG1 and MG2, in limb survival rates. EG1 and MG3 showed no statistical difference in limb survival and EG2 had a better limb survival than MG3. CONCLUSION: Results suggest that the administration of streptokinase does not change effects of venous occlusion and that hyperbaric oxygen therapy may decrease the effects of venous occlusion in limbs.

Estreptoquinase e oxigênio hiperbárico em congestão após reimplante de membro / Effects of streptokinase and hyperbaric oxygen therapy on venous occlusion after limb reimplantation in rats

OBJETIVO: Foram testados os efeitos do fármaco estreptoquinase e da terapia com oxigênio hiperbárico em modelo experimental de oclusão venosa após reimplante de membro. MÉTODOS: Foram realizadas amputações com preservação de vasos e nervos dos membros posteriores direitos de 140 ratos. Os grupos GM0, GM1, GM2, GM3 e GM4 foram submetidos a tempos de oclusão venosa de zero, uma, duas, três e quatro horas. Os grupos GE1 e GE2 foram tratados com estreptoquinase e terapia com oxigênio hiperbárico, respectivamente, após oclusão venosa de três horas. Os resultados foram analisados estatisticamente pelo teste do Qui-quadrado (p<0,05). RESULTADOS: As taxas de mortalidade transoperatórias dos grupos GM0, GM1, GM2, GM3 e GM4 foram 0 por cento, 10 por cento, 15 por cento, 30 por cento e 60 por cento e as pós-operatórias foram 5 por cento; 11,1 por cento; 11,7 por cento; 14,2 por cento e 100 por cento, respectivamente. As taxas de viabilidade dos membros isquêmicos após sete dias de avaliação foram 100 por cento, 87,5 por cento, 80 por cento e 66,67 por cento. As taxas de viabilidade dos grupos GE1 e GE2 foram 76,9 por cento e 100 por cento, respectivamente. As taxas de mortalidade transoperatórias foram diferentes estatisticamente com exceção de GM1 e GM2. As taxas de mortalidade pós-operatórias não foram diferentes com exceção de GM3 e GM4. As taxas de viabilidade dos grupos modelo foram diferentes entre si, exceto os grupos GM1 e GM2. GE1 resultou em uma viabilidade de membros sem diferença estatística e GE2 em uma viabilidade de membros maior que GM3. CONCLUSÃO: A estreptoquinase não alterou os efeitos da oclusão venosa e a terapia com oxigênio hiperbárico aumentou a viabilidade dos membros.

OBJECTIVE: The effectiveness of streptokinase and hyperbaric oxygen therapy on venous occlusion after limb reimplantation was tested in rats. METHODS: Amputation with preservation of vessels and nerves of the right hind limb was carried out in 140 rats. Groups MG0, MG1, MG2, MG3 and MG4 were submitted to 0, 1, 2, 3 and 4 hours of venous occlusion. MG3 was elected as control for the experimental groups. Groups EG1 and EG2 were submitted to 3 hours of venous occlusion and were treated with streptokinase and hyperbaric oxygen therapy. Limbs were observed for 7 days and their mortality and survival rates were studied. RESULTS: Trans-operatory mortality rates in groups MG0, MG1, MG2, MG3 and MG4 were 0, 10, 15, 30 and 60 percent respectively and the postoperatory mortality rates were 5; 11.1; 11.7; 14.2 and 100 percent respectively. The limb survival rates were 100 percent, 87.5 percent, 80 percent and 66.67 percent respectively and 76.9 percent and 100 percent in EG1 and EG2. Model groups were statistically different, except for MG1 and MG2 in trans-operatory mortality rates. There were no statistical differences in postoperatory mortality rates between model groups except for MG3 and MG4. Model groups were statistically different, with the exception of MG1 and MG2, in limb survival rates. EG1 and MG3 showed no statistical difference in limb survival and EG2 had a better limb survival than MG3. CONCLUSION: Results suggest that the administration of streptokinase does not change effects of venous occlusion and that hyperbaric oxygen therapy may decrease the effects of venous occlusion in limbs.

Evaluation of oxidative stress in the thrombolysis of pulmonary embolism.

BACKGROUND: To analyse leukocyte function parameters and oxidative stress (OS) in patients with acute pulmonary embolism (PE) treated with thrombolytics. METHODS: Fifteen patients undergoing thrombolysis (TL) with ultra-high dose streptokinase (n = 8), or alteplase (tPA) (n = 7) treatment were studied. Blood samples were collected prior to TL, and then 8 h, 1, 3, 5 and 30 days after treatment. Malondialdehyde (MDA), reduced glutathione (GSH), plasma protein sulfhydryl groups (PSH) levels, superoxide dismutase (SOD) and myeloperoxidase enzyme (MPO) activities were measured in plasma or whole blood for monitoring of the OS markers. Production of reactive oxygen species (ROS) in whole blood was measured by luminol dependent chemiluminescence. Flow cytometry was used to determine CD11a, CD18, and CD97 surface antigen expression on leukocytes. RESULTS: The elevated MDA, ROS and MPO, decreased GSH and PSH levels indicated the presence of OS in patients with PE. MDA significantly (P < 0.05) increased, GSH significantly (P < 0.05) decreased following thrombolysis. ROS production peaked on the 3rd and 5th days. TL was accompanied by significant decrease in granulocyte and monocyte CD11a and CD18 as well as in granulocyte CD97 expression (P < 0.05). CONCLUSION: PE led to OS that was augmented following TL. Decreased adhesion molecule expression of circulating leukocytes in the early phase of TL reflects the pathological leukocyte endothelial cell interactions.

Can streptokinase produce beneficial effects additional to coronary recanalization? Quantitative microvascular analysis of critically injured reperfused myocardium.

The aim of this study was to evaluate whether streptokinase (SK) may produce beneficial effects at the level of microvascular circulation in addition to coronary recanalization. Twenty mongrel dogs weighing 28.4 +/- 4.6 kg were randomized to receive SK (16,000-72,000 U/kg) or 20 ml saline (control) in an open-chest anterior descending artery occlusion (3 h) and reperfusion (2 h) model. Myocardial blood flow was measured by the radioactive microsphere technique and the state of microvascular circulation (red blood cell containing capillary counts and tissue red blood cell content) was evaluated in the infarcted subendocardial zone using computerized image analysis. The percentage (mean +/- SE) of cell-containing vessels normalized to nonischemic control areas was 166.5 +/- 7.5 in SK-treated infarcts while in untreated control infarcts it was more variable (130.0 +/- 15.6%) (2P > 0.1). The red blood cell content of infarcts treated with 2.0 megaunits SK was 3.9 +/- 0.6% compared with 6.7 +/- 0.9% in untreated control infarcts (2P = 0.029). Plasma viscosity was slightly reduced in SK-treated dogs (2P = 0.05), but no significant changes in blood fibrinogen, hemoglobin, blood flow, and high energy phosphate levels between control and SK-treated infarcts were observed. SK reduces congestion and results in more even reperfusion of the microvasculature in severely ischemic myocardium to which blood flow has been restored. This effect may be beneficial in the salvage and healing of clinical infarctions.

Rhinovirus inhibits antigen-specific T cell proliferation through an intercellular adhesion molecule-1-dependent mechanism.

To determine whether binding of human rhinovirus (HRV) to intracellular adhesion molecule-1 might disrupt airway immune processes, effects of a major HRV group, HRV-16, on T cell proliferation and cytotoxicity were defined. HRV (1-10 TCID50/cell) significantly inhibited T cell proliferation induced by antigen but not proliferation secondary to mitogens, interleukin-2, or an irradiated allogeneic T cell line. Noninfectious (UV-irradiated) HRV had similar effects. Inhibition of T cell proliferation was dependent on HRV binding to intercellular adhesion molecule-1 on monocytes, indicating that the virus interferes with lymphocyte activation indirectly through effects on antigen-presenting cells. In addition, HRV inhibited T cell cytotoxic responses but not NK cell activity. If these effects also occur in vivo, the resulting disturbance in local airway immunity could increase the chances of successful viral replication, and might also be a factor in the pathogenesis of secondary viral or bacterial respiratory tract infections.

Thrombolytic therapy in peripheral arterial occlusive disease: mechanisms of action and drugs available.

Catheter-directed thrombolytic therapy has become an important part of the treatment of patients with acute arterial and graft occlusion. The underlying pharmacologic principle is the activation of plasminogen, bound to fibrin within the thrombus. Guide-wire passage reliably predicts success of catheter-directed thrombolysis. The underlying disease process leading to thrombosis should be accurately identified and promptly corrected to reduce the probability of recurrent occlusion. Streptokinase (SK), urokinase (UK) and recombinant tissue plasminogen activator (rt-PA) are the three agents used to treat peripheral arterial occlusive disease. The evolution from SK to UK and rt-PA and improvements in techniques and delivery systems have led to improved success rates and lower complication rates. Patient selection, basic technical considerations and overall results are discussed here. The currently available thrombolytic agents, as well as those being developed, are reviewed to provide background information for current and future applications.

[The effect of streptase in hypoxia on the blood and abdominal aorta in rats]. / Vliianie streptazy pri gipoksii na krov' i briushnuiu aortu krys.

In the experiment of albino rats it was shown that hypobaric hypoxia caused a disorders of hemostasis with destabilization of membranes and imbalance of electrolytes in the erythrocyte-plasma-vessel wall system. Streptase administration in a dose of 2500 U/kg in this case events in some degree the changes in the process of the blood coagulation, viscosity-elasticity properties of erythrocytes, calcium levels in plasma and erythrocytes, sodium and magnium levels in the abdominal aorta wall produced by the "altitude rise" in an altitude chamber.

[The thrombolytic activity of acylated activator complexes of plasmin-streptokinase with different rates of reactivation]. / Tromboliticheskaia aktivnost' atsilirovannykh aktivatornykh kompleksov plazmin--streptokinaza s razlichnymi skorostiami reaktivatsii.

In the experiments on guinea-pigs with venous thrombosis there were studied the fibrin- and thrombolytic effects of streptokinase, the plasmin-streptokinase complex and the acylated derivatives of the complex with various rates of reactivation. It was established that the acylated derivatives of the plasmin-streptokinase complex possess greater stability in the blood flow and lead to more prolonged stimulation of fibrinolysis at less magnitude of its systemic activation. Due to this the acylated derivatives of the plasmin-streptokinase complex produce less pronounced fibrinogenolysis. In connection with a high affinity to fibrin their thrombolytic action does not depend on the systemic activation of fibrinolysis.

Effect of the thrombolytic agent, streptokinase, on the responses to endotoxemia in conscious rats.

The potential role of coagulation defects as a pathologic mediator in septic shock is well documented, especially as it relates to increased thromboxane formation, thrombocytopenia, and disseminated intravascular coagulation. The present study was designed to determine the effect of the thrombolytic agent streptokinase on the sequelae of endotoxemia in the rat. Conscious male Sprague-Dawley rats were given a bolus intravenous dose of Salmonella enteritidis endotoxin (20 mg/kg; LD90 dose) 5 min after the intravenous administration of streptokinase (10,000 U/kg bolus + 1,000 U/kg/hr infusion), or heparin (100 U/kg bolus + 30 U/kg/hr infusion). The effects of streptokinase or heparin on blood clotting were determined by measuring ex vivo clot formation 1 hr after the administration of endotoxin. In naive and endotoxemic animals, both agents significantly reduced clot formation (P less than 0.05). In endotoxemic animals, streptokinase or heparin improved survival to 70%, compared to 8% survival in the endotoxin + vehicle group (P less than 0.05). The improvement in survival with streptokinase was dose-dependent. Neither streptokinase nor heparin prevented the thrombocytopenia or hemoconcentration which developed in endotoxemic animals. These results demonstrate the potential utility of streptokinase for improving survival in endotoxemia and further confirm the deleterious contribution of coagulation disorders in endotoxic mortality.

Development and evaluation of anisoylated plasminogen streptokinase activator complex (APSAC) as a second generation thrombolytic agent.

Anisoylated plasminogen streptokinase activator complex (APSAC) was developed as a second generation thrombolytic agent in an attempt to overcome some of the limitations to the intravenous application of streptokinase for coronary artery thrombolysis. Temporary protection of the active site on the plasminogen molecule by acylation allows APSAC to be given by rapid injection, confers semiselectivity for clot (at lower doses) and prolonged fibrinolytic action. These properties may simplify intravenous administration, improve coronary reperfusion response and reduce reocclusion potential. Clinical trials with APSAC, still ongoing, allow the following tentative conclusions: the efficacy of intravenous APSAC appears to be equivalent to that of intracoronary streptokinase, when given within 4 hours of the onset of symptoms of myocardial infarction, and superior to that of intravenous streptokinase, but it is easier to administer. Early APSAC therapy leads to reperfusion rates of 60 to 65% and patency rates of 70 to 80%. Early reocclusion rates (within 24 hours) appear to be as low as or lower than those obtained with other agents. Bleeding complications and allergic manifestations after APSAC are acceptably low and comparable with those of equivalent doses of streptokinase. The potential for mortality benefit after APSAC appears to be high and is undergoing additional study. Thus, APSAC therapy, which can be given by simple injection over 2 to 5 minutes, appears promising as a future first line approach to reperfusion therapy in acute myocardial infarction.

Preclinical pharmacological evaluation of anisoylated plasminogen streptokinase activator complex.

An ideal thrombolytic (or fibrinolytic) agent is one which would generate the formation of plasmin only where it is required, i.e. bound to fibrin within the thrombus. However, the capacity of even the newer thrombolytic agents to achieve localised plasmin generation within the thrombus is relative and depends on the concentration of the agent administered. For all available activators, the concentration required for effective clinical thrombolysis is also capable of converting plasminogen to plasmin within the circulation (plasminaemia). Since the action of plasmin is not specific to fibrin, plasminaemia results in dissolution not only of fibrin but also of several other clotting factors. For example, plasmin can degrade fibrinogen and cause impaired haemostasis. The plasminogen activators which are available, or have been developed to date, include streptokinase, urokinase, pro-urokinase, anisoylated plasminogen-streptokinase activator complex (APSAC) and tissue plasminogen activator (t-PA). All of these agents have the same biochemical mechanism of action, cleaving an arginine-valine bond in the plasminogen molecule to form plasmin, but they differ with regard to other important properties. The first property to be considered is clot specificity; the ability to dissolve fibrin as opposed to fibrinogen, and also to dissolve the clot as opposed to a haemostatic plug. Unfortunately, fibrin specificity does not equate entirely with thrombus specificity, and all currently developed plasminogen activators, by dissolving fibrin, will induce the destruction of haemostatic extravascular plugs as well as intravascular thrombi. Thus, no agent is thrombus-specific in this respect. The degree of fibrinogenolysis does vary between plasminogen activators. Those which have the least effect on haemostasis or clotting capability would seem, at first, to be preferable. However, a short term reduction in fibrinogen could also be beneficial, since it may reduce the incidence of early reocclusion and, by reducing blood viscosity, improve microcirculation to the infarct zone. The intrinsic efficiency of the plasminogen activators is a second important property. In vitro, under conditions pertaining to the circulation, urokinase is about 10 times more efficient than t-PA at converting glu-plasminogen to plasmin (on the basis of the Vmax to Km ratio), while streptokinase-plasmin is 20 times more efficient. The efficiency of these activators is increased in the presence of fibrin and lys-plasminogen, 1800-fold for t-PA, 8-fold for urokinase and 180-fold for streptokinase-plasmin.(ABSTRACT TRUNCATED AT 400 WORDS)

Investigation on the interaction of commercial forms of streptokinase and human plasminogen: a potential screening procedure for fibrinolytic inhibitors.

Streptokinase activation of human plasminogen is known to produce several enzymatic entities. Initially, the identification and characterization of these various entities were based on molecular model studies which necessitated highly purified biological materials and sophisticated techniques. However, these conditions cannot always be adhered to when alacrity, precision, and cost are often the prime factors governing the choice of a method for the evaluation of therapeutic agents. Our concern was therefore to find a suitable method of investigating inhibitors of the fibrinolytic system without compromising on accuracy, reliability, and reproducibility. We found that the activation of human plasminogen by streptokinase was dependent both on the duration of the activation step and the concentration of streptokinase used. By combining these two factors, activation could be visualized as a dual phase phenomenon. Each phase revealed distinct kinetic parameters and reactivity toward inhibitors such that their identity with the known enzymatic entities could be established. Inhibitors were further assessed with respect to their kinetic profile and were found to conform to known data. Therefore, the proposed method not only allows for direct visualization of the activation process but also meets the requirements for the routine screening of potential therapeutic inhibitors of the fibrinolytic system.

[Researches on the antiaggregative activity of Ginkgo biloba extract (author's transl)]. / Recherches sur l'action antiagrégante de l'extrait de Ginko biloba. Activité au niveau des artères et des veines de la pie-mère chez le lapin.

Sodium lactate applied on the pia-mater of the rabbit induces the appearance of venous platelets thrombi. The same phenomenon occurs in the arteries after electric stimulation of the arterial wall. Gingo biloba extract, i.v. and per os, has been shown capable to partially antagonize these effects, particularly in the venous microcirculation. The ratio between the activity following the two modes of administration is about 1 to 5.

[Animal experimental studies on the thrombolytic effect of streptokinase]. / Tierexperimentelle Untersuchungen zur thrombolytischen Wirkungvon Streptokinase

The thrombolytic action of the streptokinase preparation Awelysin was investigated in animal experiments. After evaluation of the optimum fibrinolytically effective streptokinase dose and the changes in the clotting system induced by intravenous application of streptokinase experimentally produced deposition thrombi and clotting thrombi were lysed intravascularly in dogs, rabbits and rats. The success of the therapy was confirmed angiographically or rheographically.