Fibrinolytic Properties Of Microbial Proteases

1981 ◽  
Author(s):  
N S Egorov ◽  
N S Landau ◽  
G V Andreenko ◽  
V G Kreyer ◽  
S S Pokrovskaya ◽  
...  
Keyword(s):  
Blood Plasma ◽  
Intravenous Injection ◽  
Fibrinolytic Activity ◽  
Clot Lysis ◽  
Albino Rats ◽  
Ecological Groups ◽  
Fibrinolytic Enzymes ◽  
Thrombolytic Effect

Our study of 820 microorganisms from various systematic and ecological groups revealed that 72% of the cultures contained enzymes caoable to dissolve human fibrin clots in vitro. Fibrinolytic enzymes are formed during growth of producers on strictly specific media. Changes in the composition of media and conditions of enzymatic synthesis were found to increase the specificity of microbial proteases to fibrin and to decrease their sensitivity to fibrinolytic enzymes inhibitors. A thrombolytic enzyme (TE) has been isolated and purified from the cultural fluid of actinomycetes. An intravenous injection of TE to albino rats results in an increase of fibrinolytic activity of the blood plasma euglobulin fraction. Time of euglobulin clot lysis is thereby decreased by 32%. The fibrinolytic activity measured from euglobulin precipitate on un-heated fibrin plates is increased 2.3-fold. However, the fibrinolytic activity of non-diluted blood plasma remains unchanged probably due to a sharp rise in antiplasmin content following TE injection. TE exerts marked thrombolytic effect in vivo. After intravenous injection of TE to animals with artificial clots in a v.jugularis segment a rapid clot lysis and reconstitution of blood flow are observed.

scholarly journals Effect of the cholesterol content of small unilamellar liposomes on their stability in vivo and in vitro

1980 ◽  
Vol 186 (2) ◽  
pp. 591-598 ◽  
Author(s):  
Christopher Kirby ◽  
Jacqui Clarke ◽  
Gregory Gregoriadis
Keyword(s):  
Blood Plasma ◽  
Intravenous Injection ◽  
Whole Blood ◽  
Cholesterol Content ◽  
Molar Ratio ◽  
Phosphatidylcholine Liposomes ◽  
Effective Use ◽  
Positively Charged

Small unilamellar neutral, negatively and positively charged liposomes composed of egg phosphatidylcholine, various amounts of cholesterol and, when appropriate, phosphatidic acid or stearylamine and containing 6-carboxyfluorescein were injected into mice, incubated with mouse whole blood, plasma or serum or stored at 4°C. Liposomal stability, i.e. the extent to which 6-carboxyfluorescein is retained by liposomes, was dependent on their cholesterol content. (1) Cholesterol-rich (egg phosphatidylcholine/cholesterol, 7:7 molar ratio) liposomes, regardless of surface charge, remained stable in the blood of intravenously injected animals for up to at least 400min. In addition, stability of cholesterol-rich liposomes was largely maintained in vitro in the presence of whole blood, plasma or serum for at least 90min. (2) Cholesterol-poor (egg phosphatidylcholine/cholesterol, 7:2 molar ratio) or cholesterol-free (egg phosphatidylcholine) liposomes lost very rapidly (at most within 2min) much of their stability after intravenous injection or upon contact with whole blood, plasma or serum. Whole blood and to some extent plasma were less detrimental to stability than was serum. (3) After intraperitoneal injection, neutral cholesterol-rich liposomes survived in the peritoneal cavity to enter the blood circulation in their intact form. Liposomes injected intramuscularly also entered the circulation, although with somewhat diminished stability. (4) Stability of neutral and negatively charged cholesterol-rich liposomes stored at 4°C was maintained for several days, and by 53 days it had declined only moderately. Stored liposomes retained their unilamellar structure and their ability to remain stable in the blood after intravenous injection. (5) Control of liposomal stability by adjusting their cholesterol content may help in the design of liposomes for effective use in biological systems in vivo and in vitro.

Thrombolytic Properties of a Tissue Activator of Plasminogen

1979 ◽  
Author(s):  
G.V. Andreenko ◽  
E.E. Shimonaeva ◽  
T.N. Serebryakova
Keyword(s):  
Intravenous Injection ◽  
Fibrinolytic Activity ◽  
Degradation Products ◽  
Blood Clot ◽  
Blood Stream ◽  
Rat Plasma ◽  
Physiological Solution ◽  
Clot Lysis ◽  
Lysis Time

Preparations of a tissue activator of plasminogen (TA) readily soluble in the physiological solution were obtained from porcine heart according to the procedure of Bachman et al. up to the stage of precipitation by Zn( C2H3O2)2. H2O. “In vitro” the TA preparations reduced the lysis time of the rat plasma euglobulin fraction clot from 65-90 min in the control down to 7-14 min and induced the blood clot lysis. The highest rate of lysis was observed when the activator was combined with plasminogen. When TA was dissolved in rat plasma and physiological solution, the rate of the clot lysis was decreased. An intravenous injection of TA into the blood stream of rats with experimental thrombosis led to a clot lysis for 15-60 min. The rate of clot lysis was independent of the dose used. After 10 and 20 min of intravenous injection of TA the fibrinolytic activity of the plasma euglobulin fraction was increased 1,5-2-fold. The level of fibrinogen tended to a decrease. The level of degradation products was increased 1,2-1,5-fold. The fibrinolytic activity was slightly increased after 20 min. The activities of antiplasmi ns and antiactivator and the recalcification time remained unchanged.

scholarly journals Ascertainment of In vivo Antidiarrheal and In vitro Thrombolytic Effect of Ethanolic Extract of Leaves of Amomum dealbatum

2019 ◽  
Author(s):  
Md. Azimul Islam ◽  
Mohammed Aktar Sayeed ◽  
Md. Abdul Barek ◽  
Enama Nabi Shetu ◽  
Md. Nurul Faisal
Keyword(s):  
Castor Oil ◽  
Venous Blood ◽  
Ethanolic Extract ◽  
Positive Control ◽  
Negative Control ◽  
Clot Lysis ◽  
Thrombolytic Activity ◽  
Thrombolytic Effect

Aims: The present study aimed to investigate antidiarrheal and thrombolytic effect of ethanolic extract of leaves of A. dealbatum in mice. Study design: Antidiarrheal effect was evaluated by castor oil-induced diarrhea method at two different concentrations in mice and in vitro thrombolytic activity was analyzed with clot lysis assay of human blood. Place and duration of study: Department of Pharmacy, International Islamic University Chittagong, Kumira, Chittagong-4318, Bangladesh, between December 2018 and February 2019. Methodology: The male Swiss mice’s were divided into four groups (n = 5). First group was orally treated with 1% Tween-80 (10 ml/kg) and second group was orally treated with loperamide (5 mg/kg). Third and fourth group were orally treated with ethanolic extract of leaves of A. dealbatum at 200 and 400 mg/kg accordingly. Human RBCs were collected for conducting thrombolytic assay. During this study, 1.5 ml of venous blood was drawn from healthy volunteers (n = 10) and Streptokinase was employed as positive control and distilled water was employed as negative control. Results: In castor oil induced diarrhea model, ethanolic extract of leaves of A. dealbatum at 200, 400 mg/kg and loperamide (5 mg/kg) significantly reduced the number of feces and increase percent of inhibition of defecations compared to negative control. The extract showed percent of inhibition of defecation of 16.67 and 37.50 for 200 and 400 mg/ml respectively where the positive control loperamide showed 66.67%. Percentage of clot disruptions were 4.51 (p<.001), 75.69 (p<.001) and 26.07 (p<.001) for water, streptokinase and 10 mg/ml extract respectively. Conclusion: Based on the results from in vivo and in vitro activities, the leaves of A. dealbatum were found to be a potential source of new antidiarrheal and thrombolytic agents.

METABOLISM OF TESTOSTERONE AND 5α-REDUCED ANDROGENS BY THE RABBIT PROSTATE AND EPIDIDYMIS: STUDIES IN VITRO AND IN VIVO

1979 ◽  
Vol 82 (2) ◽  
pp. 207-214 ◽  
Author(s):  
W. D. BOOTH ◽  
R. JONES
Keyword(s):  
Blood Plasma ◽  
Intravenous Injection ◽  
Incubation Medium ◽  
Peripheral Circulation ◽  
Adult Rabbit ◽  
Tissue Preparation ◽  
Endogenous Steroids

SUMMARY The metabolism of radioactively labelled testosterone, 5α-dihydrotestosterone, 5α-androstane-3α,17β-diol and 5α-androstane-3β,17β-diol by the rabbit epididymis and prostate has been investigated in vitro and in vivo. In vitro, the rate of conversion of testosterone to 5α-reduced androgens was low in both glands. Varying the nature of the tissue preparation, age of animal or incubation medium did not improve the situation substantially. However, the rabbit prostate and epididymis metabolized 5α-reduced androgens readily. The prostate was particularly efficient at interconverting 5α-androstane-3α,17β-diol and 5α-dihydrotestosterone, whereas the capacity of the epididymis to carry out this step was much lower. Small amounts of 5α-androstane-3,17-dione and androsterone were also identified. Both glands interconverted 5α-dihydrotestosterone and 5α-androstane-3β,17β-diol to a comparable degree. Following the intravenous injection of 3H-labelled testosterone, significant levels of 3H-labelled 5α-dihydrotestosterone were found in the prostate and epididymis within 30 min. Furthermore, 5α-androstane-3α,17β-diol was detected in both glands. In blood plasma, the ratio of radioactively labelled testosterone: 5α-dihydrotestosterone was 2: 1, i.e. similar to that for endogenous steroids. The intravenous injection of 3H-labelled 5α-androstane-3α-17β-diol gave rise to much higher amounts of 5α-dihydrotestosterone in the prostate than in the epididymis, whereas the reverse was found for the levels of unmetabolized diol. The results indicate that the prostate and epididymis of the adult rabbit differ in their capacity to metabolize 5α-reduced androgens and that both glands depend to a large extent on the relatively high levels of 5α-dihydrotestosterone and 5α-androstanediols present in the peripheral circulation, rather than the metabolism of testosterone in situ.

Gastric Fibrinolysis

1975 ◽  
Vol 34 (02) ◽  
pp. 409-418 ◽  
Author(s):  
I. M Nilsson ◽  
S.-E Bergentz ◽  
U Hedner ◽  
K Kullenberg
Keyword(s):  
Gastric Ulcer ◽  
Gastric Juice ◽  
High Activity ◽  
Fibrinolytic Activity ◽  
Duodenal Juice ◽  
Bleeding Tendency ◽  
Local Fibrinolysis ◽  
Heated Plates

SummaryGastric juice from 15 normals, 20 patients with gastric ulcer and 4 patients with erosive haemorrhagic gastroduodenitis was investigated in respect of its activity on unheated and heated fibrin plates and its content of FDP and plasminogen or plasmin with immunochemical methods. Gastric juice from normals showed no activity on unheated and heated fibrin plates, and no FDP or plasminogen could be demonstrated. In the patients with gastric ulcer the gastric juice showed little or no fibrinolytic activity on fibrin plates except in 2, who had regurgitation of duodenal juice and neutral pH of the juice. These patients had equally high activity on heated as on unheated plates and no plasmin could be demonstrated. It was shown that this activity was not due to fibrinolysis, but to non-specific proteolytic activity (probably trypsin). The patients with erosive haemorrhagic gastroduodenitis exhibited quite a different picture. The gastric juice from these patients showed extremely high activity on fibrin plates, the activity was higher on unheated than on heated plates. The activity was inhibited in vitro by addition of EACA and in vivo after administration of AMCA. The occurrence of plasmin could be demonstrated directly immunologically in the gastric juice. By comparison of plasmin and trypsin in various assays it could further be proved that the gastric juice in these cases contained plasminogen activator and plasmin. The patients with erosive haemorrhagic gastroduodenitis showed no increase in fibrinolysis in the blood, but low values for plasminogen and α2M, and the serum contained FDP. These findings in the blood and gastric juice were interpreted as signs of local fibrinolysis in the stomach and duodenum. There is reason to assume that this gastric fibrinolysis contributes substantially to the bleeding tendency. The effect of administration of AMCA on fibrinolytic activity and the haemorrhage lends support to the assumption of such a mechanism.

Anti-thrombotic Effect of a PAI-1 Inhibitor in Rats Given Endotoxin

1996 ◽  
Vol 75 (01) ◽  
pp. 118-126 ◽  
Author(s):  
T Abrahamsson ◽  
V Nerme ◽  
M Strömqvist ◽  
B Åkerblom ◽  
A Legnehed ◽  
...  
Keyword(s):  
Plasminogen Activator Inhibitor ◽  
Rat Plasma ◽  
Clot Lysis ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Fab Fragment ◽  
Dose Dependent Decrease ◽  
Pai 1

SummaryThe aim of this study was to investigate the anti-thrombotic effects of an inhibitor of the plasminogen activator inhibitor-1 (PAI-1) in rats given endotoxin. In studies in vitro, PRAP-1, a Fab-fragment of a polyclonal antibody against human PAI-1, was shown to inhibit PAI-1 activity in rat plasma as well as to stimulate clot-lysis of the euglobulin fraction derived from rat plasma. Endotoxin administered to anaesthetised rats produced a marked increase in plasma PAI-1 activity. To study fibrin formation and lysis in vivo after intravenous (i. v.) injection of the coagulant enzyme batroxobin, 125I-fibrinogen was administered to the animals. The thrombi formed by batroxobin were rapidly lysed in control animals, while the rate of lysis was markedly attenuated in rats given endotoxin. PRAP-1 was administered i.v. (bolus + infusion) to rats given endotoxin and batroxobin and the PAI-1 inhibitor caused a dose-dependent decrease in the 125I-fibrin deposition in the lungs. An immunohistochemical technique was used to confirm this decrease in density of fibrin clots in the tissue. Furthermore, PRAP-1 decreased plasma PAI-1 activity in the rats and this reduction was correlated to the decrease in lung 125I-fibrin deposition at the corresponding time point. It is concluded that in this experimental model the PAI-1 antibody PRAP-1 may indeed inhibit thrombosis in animals exposed to endotoxin.

A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

1977 ◽  
Vol 37 (01) ◽  
pp. 154-161 ◽  
Author(s):  
B. A Janik ◽  
S. E Papaioannou
Keyword(s):  
Side Effects ◽  
Effective Dose ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Plasminogen Activators ◽  
Assay System ◽  
Coagulation Parameters ◽  
Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

The Roles of α2-Antiplasmin and Plasminogen Activator Inhibitor 1 (PAI-1) in the Inhibition of Clot Lysis

1993 ◽  
Vol 70 (02) ◽  
pp. 301-306 ◽  
Author(s):  
Linda A Robbie ◽  
Nuala A Booth ◽  
Alison M Croll ◽  
Bruce Bennett
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Plasminogen Activator Inhibitor 1 ◽  
Dependent Inhibition ◽  
Activator Inhibitor ◽  
Pai 1

SummaryThe relative importance of the two major inhibitors of fibrinolysis, α2-antiplasmin (α2-AP) and plasminogen activator inhibitor (PAI-1), were investigated using a simple microtitre plate system to study fibrin clot lysis in vitro. Cross-linked fibrin clots contained plasminogen and tissue plasminogen activator (t-PA) at concentrations close to physiological. Purified α2-AP and PAI-1 caused dose-dependent inhibition. All the inhibition due to normal plasma, either platelet-rich or poor, was neutralised only by antibodies to α2-AP. Isolated platelets, at a final concentration similar to that in blood, 2.5 × 108/ml, markedly inhibited clot lysis. This inhibition was neutralised only by antibodies to PAI-1. At the normal circulating ratio of plasma to platelets, α2-AP was the dominant inhibitor. When the platelet:plasma ratio was raised some 20-fold, platelet PAI-1 provided a significant contribution. High local concentrations of PAI-1 do occur in thrombi in vivo, indicating a role for PAI-1, complementary to that of α2-AP, in such situations.

The Effects of Some Synthetic Compounds on In Vitro Fibrinolytic Activity Measured by Different Methods and the Relevance to Activity In Vivo

1972 ◽  
Vol 28 (03) ◽  
pp. 351-358
Author(s):  
A.J Baillie ◽  
A. K Sim
Keyword(s):  
Inhibitory Activity ◽  
Substrate Concentration ◽  
Fibrinolytic Activity ◽  
Synthetic Compounds ◽  
In Vitro Methods ◽  
Narrow Concentration Range

SummaryThe activity of several synthetic compounds, rated from good to poor (or inactive) fibrinolytic activators, has been assessed by two different commonly-used in vitro methods. Compounds shown to be active over a narrow concentration range in the hanging clot test were shown to be inhibitors of plasmin and trypsin in the casein-olytic test. The inhibitory activity of these compounds was shown to increase with increasing substrate concentration and apparent activity in the hanging clot test. Possible explanations and relevance of these observations are discussed.

Synthesis, Characterization and in vivo Evaluation of PEGylated PPI Dendrimer for Safe and Prolonged Delivery of Insulin

2019 ◽  
Vol 9 (3) ◽  
pp. 248-263 ◽  
Author(s):  
Ashish K. Parashar ◽  
Preeti Patel ◽  
Arun K. Gupta ◽  
Neetesh K. Jain ◽  
Balak Das Kurmi
Keyword(s):  
Blood Glucose ◽  
Drug Release ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Albino Rats ◽  
Sustained Delivery ◽  
In Vivo Evaluation ◽  
Hemolytic Toxicity

Background: The present study was aimed at developing and exploring the use of PEGylated Poly (propyleneimine) dendrimers for the delivery of an anti-diabetic drug, insulin. Methods: For this study, 4.0G PPI dendrimer was synthesized by successive Michael addition and exhaustive amidation reactions, using ethylenediamine as the core and acrylonitrile as the propagating agent. Two different activated PEG moieties were employed for PEGylation of PPI dendrimers. Various physicochemical and physiological parameters UV, IR, NMR, TEM, DSC, drug entrapment, drug release, hemolytic toxicity and blood glucose level studies of both PEGylated and non- PEGylated dendritic systems were determined and compared. Results: PEGylation of PPI dendrimers caused increased solubilization of insulin in the dendritic framework as well as in PEG layers, reduced drug release and hemolytic toxicity as well as increased therapeutic efficacy with reduced side effects of insulin. These systems were found to be suitable for sustained delivery of insulin by in vitro and blood glucose-level studies in albino rats, without producing any significant hematological disturbances. Conclusion: Thus, surface modification of PPI dendrimers with PEG molecules has been found to be a suitable approach to utilize it as a safe and effective nano-carrier for drug delivery.

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