In Vitro Studies on the Mechanism of the Antifibrino-lytic Action of E-Aminocaproic Acid (EACA)

1968 ◽  
Vol 19 (03/04) ◽  
pp. 584-592 ◽  
Author(s):  
Hanna Lukasiewicz ◽  
S Niewiarowski
Keyword(s):  
Aminocaproic Acid ◽  
Test Tube ◽  
In Vitro Studies ◽  
Lytic Action ◽  
Human Plasminogen ◽  
Experimental Findings ◽  
Fibrin Clots

Summary and Conclusion1. It has been found that EACA does not inhibit activation of human plasminogen into plasmin by SK and UK in a concentration of 5 × 10–2 M. The activation of bovine plasminogen by SK and UK is inhibited by this concentration of EACA but not by a lower one.2. EACA in concentrations of 1,5 × 10–1 – 10–4 M does not inhibit casein proteolysis by plasmin. The proteolysis of fibrinogen and fibrin measured by the release of TCA soluble tyrosine is inhibited by EACA in concentrations of 1,5 × 10–1 – 10–2 M.3. The lysis of non-stabilized clots by plasmin measured in a test tube was inhibited by an EACA concentration of 5 × 10–3 – 5 × 10–4 M. The lysis of stabilized clots by plasmin was inhibited by an EACA concentration of 10–5 M.4. On the basis of experimental findings and data given in literature the authors postulate that the mechanism of the antifibrinolytic effects of EACA consists mainly in a modification of plasmin action on fibrin. These effects are dependent on the structure of the fibrin clots.

scholarly journals In Vitro Studies of Persister Cells

2020 ◽  
Vol 84 (4) ◽  
Author(s):  
Niilo Kaldalu ◽  
Vasili Hauryliuk ◽  
Kathryn Jane Turnbull ◽  
Agnese La Mensa ◽  
Marta Putrinš ◽  
...  
Keyword(s):  
Immune System ◽  
Bacterial Growth ◽  
Molecular Mechanisms ◽  
Test Tube ◽  
In Vitro Studies ◽  
Recurrent Infections ◽  
Persister Cells ◽  
Persistent Infections ◽  
Key Aspects

SUMMARY Many bacterial pathogens can permanently colonize their host and establish either chronic or recurrent infections that the immune system and antimicrobial therapies fail to eradicate. Antibiotic persisters (persister cells) are believed to be among the factors that make these infections challenging. Persisters are subpopulations of bacteria which survive treatment with bactericidal antibiotics in otherwise antibiotic-sensitive cultures and were extensively studied in a hope to discover the mechanisms that cause treatment failures in chronically infected patients; however, most of these studies were conducted in the test tube. Research into antibiotic persistence has uncovered large intrapopulation heterogeneity of bacterial growth and regrowth but has not identified essential, dedicated molecular mechanisms of antibiotic persistence. Diverse factors and stresses that inhibit bacterial growth reduce killing of the bulk population and may also increase the persister subpopulation, implying that an array of mechanisms are present. Hopefully, further studies under conditions that simulate the key aspects of persistent infections will lead to identifying target mechanisms for effective therapeutic solutions.

Origin of Soluble Crosslinked Fibrin Oligomers: An in Vitro Study

1979 ◽  
Author(s):  
R. Hafter ◽  
R.V. Hugo ◽  
H. Graeff
Keyword(s):  
Gel Filtration ◽  
In Vitro Study ◽  
In Vitro Studies ◽  
Vitro Study ◽  
Simultaneous Action ◽  
Contrast Reaction ◽  
Combined Action ◽  
Fibrin Clots

In patients with DIC crosslinked high molecular fibrin derivatives (CL-HMD)are observed, which are eluted by gel filtration in the exclusion volume (MW>106 ). Characterization by PAGE revealed that their subunits are similar to crosslinked fdp X. To evaluate their origin, in vitro studies were performed on fibrinolysis products obtained in three ways; (1) by SK-induced fibrinolysis of crosslinked fibrin, (2) by simultaneous action of thrombin and plasmin on Fg in presence of F XIII and Ca++, and (3) by limited fibrinogenolysis and subsequent action of thrombin and F XIII upon the resultant early FDP. Reaction (1) resulted in low mol derivatives (LMD) only (D-D, E ), which do not complex with Fg. In contrast, reaction (2) and (3) resulted in HMD and LMD. The former are composed of Cl-‘X’ and complexes of mainly ‘X’ and ‘Y’. In reaction (3) early X precipitates when it is transformed to ‘X’ and to CL-’X’. Late X remains soluble after transition to ‘X’ and CL-’X’. The results suggest, that CL-HMD observed in patients with DIC are not derived from fibrin clots but formed from Fg under combined action of plasmin and thrombin

A Study of Proteolytic and Fibrinolytic Factors in the Human Prostate

1971 ◽  
Vol 25 (03) ◽  
pp. 481-498 ◽  
Author(s):  
Michelle Nijs ◽  
Christiane Brassinne ◽  
A Coune ◽  
H. J Tagnon
Keyword(s):  
Proteolytic Activity ◽  
Trypsin Inhibitor ◽  
Aminocaproic Acid ◽  
Soybean Trypsin Inhibitor ◽  
Clinical State ◽  
Plasminogen Activation ◽  
The Third ◽  
Human Plasminogen ◽  
Epsilon Aminocaproic Acid

SummaryAn analysis of the proteolytic factors contained in human prostatic tissue was performed in vitro. Casein, fibrinogen and fibrin, non-radioactive and radioiodinated were used as substrates.A first factor, called direct proteolytic activity, capable of proteolyzing casein without prior activation, is described. It had no effect on fibrinogen or fibrin, was inhibited by epsilon aminocaproic acid, but not by the soybean trypsin inhibitor. This shows that this proteolytic activity was quite different from plasmin.A second factor, called plasminogen proactivator, was demonstrated on bovine plasminogen in the presence of streptokinase, the latter being unable to produce direct activation of bovine plasminogen. Activation of this system resulted in the transformation of plasminogen into plasmin, capable of digesting casein as well as fibrinogen and fibrin. Epsilon aminocaproic acid and the soybean trypsin inhibitor inhibited this system. The properties of this proactivator show that it probably does not result from the presence of small amounts of plasminogen in the prostate. Urokinase, a factor present in human urine, is able to activate this proactivator under certain conditions.The third factor, called plasminogen activator, was capable of activating directly human plasminogen into plasmin. It was not active on bovine plasminogen. Epsilon aminocaproic acid and the soybean trypsin inhibitor were effective inhibitors. Addition of large volumes of human prostatic extract to human plasminogen resulted in a paradoxical decrease of the proteolytic activity suggesting the possible existence in the prostate of an inhibitor of this third factor.Possible relationships between these factors and the clinical state of fibrinolysis observed in some cases of disseminated prostatic cancer are discussed.

In vitro - studies with antler bone cells: Structure forming capacity, osteocalcin production and influence of sex steroids

2006 ◽  
Vol 15 (04) ◽  
pp. 245-257 ◽  
Author(s):  
H. J. Rolf ◽  
K. G. Wiese ◽  
H. Siggelkow ◽  
H. Schliephake ◽  
G. A. Bubernik
Keyword(s):  
Sex Steroids ◽  
Bone Cells ◽  
In Vitro Studies ◽  
Osteocalcin Production

The Venom of the Boomslang (Dispholidus Typus): In Vivo and in Vitro Studies

1969 ◽  
Vol 21 (02) ◽  
pp. 234-244 ◽  
Author(s):  
N Mackay ◽  
J.C Ferguson ◽  
Antonia Bagshawe ◽  
A.T.T Forrester ◽  
G.P Mcnicol
Keyword(s):  
In Vitro Studies

SummaryAn account is given of the effects of boomslang venom in man. Evidence was found of a fibrinolytic state apparently secondary to the coagulant action of the venom. These features rapidly responded to the administration of specific antivenom. In vitro studies, using a homogenate of boomslang parotids, confirmed the coagulant properties of the venom and showed them to be of much greater potency than the proteolytic actions.

Inhibition of Fibrinolysis and Fibrinogenolysis in Man: Comparison of ε-Aminocaproic Acid and Kallikrein Inhibitor

1963 ◽  
Vol 10 (01) ◽  
pp. 106-119 ◽  
Author(s):  
E Beck ◽  
R Schmutzler ◽  
F Duckert ◽  
Keyword(s):  
Aminocaproic Acid ◽  
Side Reactions ◽  
In Vitro Tests ◽  
Factor V ◽  
Clinical Use ◽  
Strong Inhibitor ◽  
Kallikrein Inhibitor ◽  
Therapeutic Possibilities

SummaryInhibitor of kallikrein and trypsin (KI) extracted from bovine parotis was compared with ε-aminocaproic acid (EACA): both substances inhibit fibrinolysis induced with streptokinase. EACA is a strong inhibitor of fibrinolysis in concentrations higher than 0, 1 mg per ml plasma. The same amount and higher concentrations are not able to inhibit completely the proteolytic-side reactions of fibrinolysis (fibrinogenolysis, diminution of factor V, rise of fibrin-polymerization-inhibitors). KI inhibits well proteolysis of plasma components in concentrations higher than 2,5 units per ml plasma. Much higher amounts of KI are needed to inhibit fibrinolysis as demonstrated by our in vivo and in vitro tests.Combination of the two substances for clinical use is suggested. Therapeutic possibilities are discussed.

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