Activation of factor XII in plasma from rats pretreated with tranexamic acid. Inhibition of a plasmin-induced loss of the functional activity of high molecular weight kininogen

Incubation of plasma from rats pretreated with tranexamic acid (40 mg/100 g) with acetone (23% V/V) yielded enzyme preparations in which all the plasminogen present was recovered as plasmin and a plasmin-like substance without affinity for lysine-Sepharose. This substance, designated "plasmin", was separated from plasmin and kallikrein in a three-step procedure using columns of lysine-Sepharose, DEAE-Sephadex A-50, and arginine-Sepharose. The ratios of fibrinolytic, caseinolytic, LEe esterase, BAEe esterase and kininogenase activities of "plasmin" corresponded well with those of rat plasmin and human plasmin. Both rat plasmin and "plasmin" destroyed the capacity of high molecular weight kininogen (HMWK) to function as a cofactor in the activation of factor XII in rat plasma, without causing a corresponding release of the kinin part of the molecule. Rat plasma kallikrein induced full release of kinin from HMWK, but the functional capacity was retained. It is suggested that the reduced extent of activation of factor XII observed in plasma from rats injected intravenously with dextran, or rat plasma that has been passed through a column with lysine-Sepharose, is due to the loss of functional HMWK caused by plasmin activated in vivo or on the column.

Different assessment of plasmin with different substrates. In vitro alteration of plasmin, influence of epsilon-aminocaproic acid and tranexamic acid upon its activity

The alteration of human and porcine plasmin and the influence of EACA and AMCHA on their activity were investigated. Solutions of both plasmins undergo storage induced alteration, which is best recorded by Chromozym PL, whereas the other chromogenic substrates, S-2251 and S-2302, and casein are less sensitive, and the fibrin plate inadequate. Plasmin amidolytic and fibrinolytic activity is maximally enhanced at 7.6 x 10(-3) M EACA and 6.4 x 10(-4) M AMCHA, and decay through storage is reversed. The caseinolytic activity seems slightly inhibited at the same EACA and AMCHA concentrations. Our results show: 1. The quotient: plasmin activity towards Chromozym PL/Activity towards S-2251 is a useful indicator of "plasmin quality". The quotient decreases markedly upon storage of plasmin solutions. 2. Plasmin stability is improved in the presence of AMCHA. 3. It is valueless to add EACA or AMCHA to inhibit plasmin in amidolytic assays since the chosen concentration enhances the amidolytic activity of already formed plasmin.

Irradiation and gastro-intestinal fibrinolysis: an experimental study in the rat

Tissue fibrinolysis in the rat stomach and transverse colon was studied after X-ray irradiation of the abdomen. Tissue biopsies were examined on unheated fibrin plates and with a histochemical technique modified from Todd. A significantly increased fibrinolytic activity was found in the mucosa of the stomach and colon 3 days after irradiation, while fibrinolysis localized to submucosal vessels was unchanged. Mucosal fibrinolysis in the stomach was significantly inhibited by intragastric administration of tranexamic acid.

A simple rapid method for isolating soluble fibrin complexes from fibrinogen by treatment with thrombin and t-AMCHA

Using treatment with thrombin associated with trans-aminomethylcyclohexane carboxylic acid (t-AMCHA), a simple and rapid method for isolating soluble fibrin complexes (SFC) from fibrinogen in the plasma was developed. By this procedure, the recovery rates of SFC and early FDP (mainly X) increased according to the concentration of t-AMCHA, reaching a maximum at 286 mM t-AMCHA. On the other hand, the recovery rate of fibrinogen remained below 1.5% and that of late FDP was almost 100% at all concentrations of t-AMCHA. These results suggested that SFC and FDP could be isolated from fibrinogen by thrombin and t-AMCHA (286 MM) treatment. Moreover, it was possible to isolate SFC from FDP using gel filtration after treatment with thrombin and t-AMCHA. The SFC could be quantified by assay of the eluted fractions containing SFC by the staphylococcal clumping test.

Tranexamic acid and gastric fibrinolysis in the rat

An optimal inhibition of tissue fibrinolysis, studied by a histochemical fibrin slide technique in the rat stomach, was obtained by administration of tranexamic acid in a dose of 60 mg/100 g body weight. A significant fibrinolysis inhibition was found within 5 min, when tranexamic acid in this dose was given either intravenously or intragastrically. A prolonged duration of fibrinolysis inhibition was observed after intragastric administration. After 4 hr no inhibitory effect of tranexamic acid could be recorded, irrespective of the route of administration.

Studies on the mechanism of action of cetraxate [4'-(2-carboxyethyl)phenyl trans-4-aminomethyl cyclohexanecarboxylate hydrochloride], a new anti-ulcer agent

To elucidate mechanisms involved in the anti-ulcer action of cetraxate, the effects of this agent on the ulcer index (UI), fibrinolytic activity (FA) and contents of several connective tissue components in ulcer tissue were examined using aspirin- and acetic acid ulcers in rats. In aspirin ulcer, cetraxate (100 and 300 mg/kg p.o.), like tranexamic acid (500 mg/kg p.o.), epsilon-aminocaproic acid (500 mg/kg p.o.) and gefarnate (200 mg/kg p.o.), inhibited both the UI and FA. However, aluminum sucrose sulfate (1000 mg/kg p.o.) was effective only against the UI and L-glutamine (500 mg/kg p.o.) failed to inhibit both parameters. In acetic acid ulcer, following oral, daily X either 5 or 8 administrations, cetraxate (200 and 300 mg/kg), gefarnate (200 mg/kg), aluminum sucrose sulfate (1000 mg/kg) and L-glutamine (500 mg/kg) were effective on both the UI and FA. Tranexamic acid (500 mg/kg) and epsilon-aminocaproic acid (500 mg/kg) were ineffective on the UI, although both agents inhibited FA. In acetic acid ulcer, cetraxate induced increases in hexosamine and uronic acid, that is, acid mucopolysaccharides (AMPS), especially chondroitin sulfate A and -C, whereas L-glutamine and aluminum sucrose sulfate resulted in increases in hexosamine and sialic acid, that is, glycoproteins. From these results, cetraxate may mainly accelerate the ulcer healing by increasing AMPS in ulcer tissue. Moreover, the local anti-FA property of this agent may be also beneficial in treating bleeding ulcers.

Haemostasis during transvesical prostatic adenomectomy. A controlled trial on the effect of drugs with antifibrinolytic and thrombin-like activities

Blood loss, plasma fibrinolytic activity, prothrombin, P.T.T., and fibrinogen plasma levels were measured in 30 patients subjected to transvesical adenomectomy. These parameters were evaluated during 7 consecutive days after the operation. Ten patients received the antifibrinolytic substance (AMCHA), ten patients received Bothrops Jararaca venom extract, and ten patients served as controls. The results show that the coagulating fraction of Bothrops Jararaca snake venom reduces intraoperative bleeding without influencing the haemostatic balance. Postoperative haematuria could be reduced by antifibrinolytic agents.

Release of plasminogen activator from normal and neoplastic endometrium

In the medium of endometrial carcinoma cultures, anti-urokinase-reacting plasminogen activator was released in contrast to cultures of normal or hyperplastic endometrium.

Tranexamic acid and corneal deturgescence

Recent work has demonstrated decreased corneal thickness in patients with Fuch's dystrophy and in patients following cataract extraction who were given systemic acid. Although tranexamic acid is a known antifibrinolytic drug its mechanism in reducing corneal thickness is not known. This experiment demonstrated no increase in the rate of corneal deturgescence of swollen rabbit corneas in the specular microscope when they were perfused for three h with 1 mM or 10 mM tranexamic acid. Pre-treatment of rabbits with intravenous tranexamic acid for three days and subsequent perfusion of corneas with tranexamic acid 10 mM also did not increase the rate of corneal deturgescence when compared with controls.

Allosteric effects of some antifibrinolytic amino acids on the catalytic activity of human plasmin

The effects of L-lysine, 6-aminohexanoic acid, and trans-4-aminomethylcy-clohexane-1-carboxylic acid on the catalytic activity of plasmin (EC 3.4.21.7) have been investigated. The kinetics of the plasmin-catlysed hydrolysis of alpha-N-benzoyl-L-arginine ethyl ester in the presence of these compounds have been studied at a number of different concentrations of the three modifiers. They each exert two effects on the reaction, an activation and an inhibition, the concentration dependencies of which are markedly different. They must therefore arise from two different interactions between plasmin and the modifier. The inhibition is competitive, so that it most probably results from direct interaction at the catalytic site. The activation is kinetically non-competitive. The experimental observations seem to be explained best by assuming that L-lysine and certain analogous compounds function as both allosteric modifiers and competitive inhibitors of plasmin.

[The enzymatic linkage of fibrinogenesis and fibrinolysis (author's transl)]

The coagulation cascade can be triggered by an extrinsic or intrinsic signal. The response is a highly complex activation sequence of several serine proteases. This physiological event of hemostasis comprises the activation of the kinin system as well as other plasma constituents. As an expression of the dynamic balance between fibrinogenesis and fibrinolysis plasminogen is activated either by proteases deriving from the blood clotting cascade or by its linkage to the kallikrein kinin system. Inhibitors of the fibrinolytic events have to be directed specifically against serine proteases or they may be used to interact with the substrate fibrin thus its degradation is delayed.

A double-blind study of the influence of tranexamic acid on the central corneal thickness after cataract extraction

A double-blind study of the influence of systemic tranexamic acid on the central corneal thickness after cataract extraction was performed in 17 pairs of patients. Apart from the cataract, no were present. A sequential statistics was used to show that the increase in central corneal thickness after operation was significantly less in the tranexamic acid treated group than in the placebo group. There was no significant difference in intraocular pressure between the tranexamic acid and the placebo treated group. The possible influence of tranexamic acid on the thickness controlling mechanism of the cornea is discussed, and studies concerning the fibrinolytic system, the complement system and the aqueous humour amino acid treated patients are mentioned.

Hemorrhagic necrosis of the intestinal mucosa associated with disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC), experimentally induced by endotoxin, caused severe hemorrhagic necrosis of the intestinal mucosa in dogs. Microscopic observation showed tortuous thrombus formation in the microcirculation of the villi. Ligation of the pancreatic and bile ducts, or administration of heparin protected the mucosa from hemorrhagic necrosis, while systemic administration of tranexamic acid increased the intestinal mucosal lesion. Local pretreatment of the intestinal mucosa by Trasylol or tranexamic acid reduced the degree of hemorrhagic necrosis. It is concluded that intravascular coagulation in the microcirculation of the intestinal mucosa, as well as pancreatic proteases, play a role in the pathogenesis of hemorrhagic necrosis in the intestine associated with DIC.

The effect of fibrinolytic inhibition in the resolution of experimental vitreous hemorrhage

Complete inhibition of vitreous fibrinolytic activity with 4-amino-methylcyclohexane carbonic acid was associated with significantly delayed resolution of vitreous hemorrhages in rabbits. However, polyacrylamide gel electrophoresis indicated but a slight delay in the removal of the fibrin component of vitreous clots, and most of the residual vitreous opacity comprised intact red blood cells. Fibrin degradation products may act as chemotactic agents, promoting the removal of red blood cells by leukocytes; hence, their absence in treated rabbits might explain in part the delayed red blood cell clearance.

Effects of t-AMCHA and EACA on the plasma kallikrein system

Varied amounts of t-AMCHA or EACA added to non-contact fresh dog plasma generates kininogenase and TAME esterase activities. These phenomena may be abolished by prior addition of lima bean trypsin inhibitor. t-AMCHA or EACA had no effect on partially purified kallikrein, but had a significant inhibitory influence on plasma kininase. The generation of prekallikrein activator with t-AMCHA was ascertained by gel filtration on a Sephadex G-100 column. The blood kinin level increased about 50% one hr after administration of t-AMCHA. It is suggested from these results that t-AMCHA may initiate the true activation of the kallikrein system by activating the Hageman factor.

Fibrinolysis in normal plasma and blood: evidence for significant mechanisms independent of the plasminogen-plasmin system

Fibrinolytic activity of normal plasma and blood has been measured by 125l-fibrin solid phase assay. Activity of plasma is not affected by removal of plasminogenplasmin by affinity chromatography. Activities of euglobulin and pseudoglobulin fractions are approximately equal. epsilon-aminocaproic acid (EACA) (10 mM), tranexamic acid (10 mM), diisopropylfluorophosphate (DFP, 50 mM), and soybean and lima bean trypsin inhibitors (100 mug/ml) do not inhibit plasma activity at concentrations that inhibit pure plasmin and urokinase-activated plasma. Activity is not affected by glass contact and is not inhibited by inhibitors of contact or enzymatic activation of Hageman factor (hexadimethrine bromide, 100 mug/ml; cytochrome C, 250 mug/ml; spermidine, 2 mM; phenylmethylsulfonylfluoride, 1 mM). It is inhibited partially (30%-40%) by heating (56 degrees C, 30 min) and by zymosan (2.5 mg/ml; 40%-90% inhibition), and is increased by hydrazine (20 mM), salicylaldoxime (20 mM), DFP (50 mM), and tosyl-L-arginine methyl ester (TAMe, 10 mM)-the latter two at concentrations known to inhibit Cls of the classic, and factor D of the alternate complement pathways. Increase fibrinolytic activity with TAMe is associated with reciprocal decrease in classic and alternate complement pathway activity. It is concluded that normal plasma fibrinolytic activity is relatively independent of plasmin as the ultimate fibrinolytic enzyme, that Hageman factor-dependent pathways are of minor importance, and that significant heat-stable and heat-labile nonplasmin fibrinolytic activities are operative. These may include proteinases involved in complement activation, and in common control of classic and alternate complement pathways, as well as other nonplasmin proteinases.

Inhibition of the development of the cellular slime mould Dictyostelium discoideum by omega-aminocarboxylic acids

Four omega-aminocarboxylic acids - epsilon-aminocaproic acid (EACA), trans-4-aminomethylcyclohexane-1-carboxylic acid (t-AMCHA), p-aminomethylbenzoic acid (PAMBA) and omega-aminocaprylic acid (OACA) -- prevented fruiting body formation of the cellular slime mould Dictyostelium discoideum. At concentrations of 40 mM, 75 mM, 10 mM and 5 mM, respectively, they allowed aggregation but prevented all further development at 24 degrees C. At lower concentrations, EACA allowed fruiting body formation but with a reduced number of spores per fruiting body. Only t-AMCHA had a significant inhibitory effect on the growth of myxamoebae. EACA affected development only if it was present between 8 and 16 h after the cells were deposited on the filters. Its effect was enhanced by high salt concentrations and by higher temperature, and was also dependent on the manner in which the cells were grown. Only strains capable of axenic growth displayed this sensitivity to EACA, although strains carrying only one of the genetic markers for axenic growth (axe A) were partially sensitive.

Echo-encephalographic study of ventricular dilatation after subarachnoid hemorrhage, with special reference to the effect of antifibrinolytic treatment

Echo-encephalographic examinations were performed in 144 patients after subarachnoid hemorrhage. Ninety-three of the patients received antifibrinolytic treatment (AMCA). The width of the third ventricle could be measured in all the patients, and lateral ventricle measurements were obtained in 94 patients. Third ventricular dilatation developed in 78 patients (54 per cent), and lateral ventricle enlargement was seen in 55 patients (58 per cent of those examined). The incidence of third ventricle dilatation was higher in the AMCA-treated group (62.5 per cent) than in the non-treated group (39.2 per cent), and this difference was statistically significant (P less than 0.05). The hydrocephalus in most cases developed 2-3 weeks after the bleeding, and reached its peak within the first 2-3 months, with subsequent complete or partial normalization of the ventricular size. At later follow-up examinations 1-4 years after the bleeding, only nine patients had persisting dilatation of moderate or pronounced degree. There was no indication that the dilatation was more severe or pronounced degree. There was no indication that the dilatation was more severe or protracted in the AMCA-treated group than in the non-treated group. In 11 patients the hydrocephalus required a shunt-operation, but the frequency of shunt-operations was not significantly different in the two groups. It is concluded that although AMCA-treated patients in comparison with non-treated patients are exposed to a somewhat higher risk of complicating hydrocephalus after subarachnoid hemorrhage, this risk cannot at present be considered as any serious contraindiction to this sort of treatment.

[Follow-up study on the hemostatic effect of the Vasolamin preparation in domestic animals]

In this paper the haemocoagulative effect of the Vasolamin preparation was examined after intravenous application in cattle, sheep, and horses by means of tests. After a laboratory confirmation of the coagulative effect of the tested preparation we used it for the purpose of haemostasis in the clinical practice. After an administration of the preparation faster coagulation of the blood was observed in all examined animals. The setting in of the effect could be observed already after 5 minutes, the maximum effect was recorded between the 15th and 30th minutes after application, and the effect lasted, although gradually weakened, for one to two hours. In the case of bleeding clinical patients the application of Vasolamin was always successful.

Patho-physiological studies on lactic acid-induced pulmonary thrombosis in rat. I. Effect of heparin, acetylsalicylic acid, urokinase and tranexamic acid

The role of platelet aggregation and coagulo-fibrinolytic systems in thrombogenesis of lactic acid-induced pulmonary thrombosis in rat were studied using an anti-coagulant, platelet aggregation inhibitor, fibrinolytic or anti-fibrinolytic agents. In normal rat, heparin (2.5 mg/kg), acetylsalicylic acid (30 mg/kg) and tranexamic acid (100 mg/kg) suppressed specifically coagulation, platelet aggregation induced by collagen or thrombin and fibrinolysis respectively. Urokinase (10,000 units/kg) activated powerfully fibrinolytic system in addition to suppressing slightly platelet aggregation. The pretreatment with heparin, acetylsalicylic acid or urokinase markedly prevented the formation of thrombus initiated by the infusion of lactic acid at the doses used. Additive effect was also obtained by combined administration of these agents. On the other hand, it was interesting to note that tranexamic acid (100 mg/kg) did not affect the thrombus formation at all despite a potent anti-fibrinolytic effect of this agent. These results indicate that both platelet aggregation and enhancement of coagulation activity are important factors responsible for the formation of thrombi in DIC, while the fibrinolytic activity in blood seems not to be involved in it. On the basis of the findings, mechanism for triggering activation of coagulation and platelet aggregation is also discussed here.

Fibrinogen-fibrin degradation products in menstrual blood from women with normal and excessive menstrual losses

Fibrinogen-fibrin degradation products, FDP, in menstrual blood during the first three days of menstrual blood during the first three days of menstruation have been investigated. Two groups of women were studied, those with normal menstrual blood loss (15 women, mean loss 30 ml, range 8-60 ml) and those with menorrhagia (14 women, mean loss 222 ml, range 107-729 ml). The following results were obtained: 1). The FDP concentrations decreased during menstruation in both groups. 2). The FDP concentrations in the two were compared for each day of the menstrual period. No differences were found between the two groups. A possible explanation of the results is given: there is a higher rate of coagulation and fibrinolysis in the endometrium of women with menorrhagia compared with women with normal blood losses. The hypothesis is supported by results of studies in which tranexamic is supported by results of studies in which tranexamic acid, an inhibitor of fibrinolysis, was given to reduce the menstrual blood loss. 3). The FDP excretion patterns differed from women to women. There were no consistent differences between the menorrhagic and the control group.