Erythrocyte Sedimentation and Soluble Fibrin Monomer Complexes

It is shown in the present work that highly significant correlation (r = 0.836) exists between the level of SFMC and the erythrocyte sedimentation rate in blood of 56 patients. No correlation of ESR with fibrinogen content was observed in 1 patient during the post-operative period, as well as in the group of experimentally infected rabbits. Administration of fibrinolysis inhibitors into rabbits (EACA, IP-315, HgCl2) caused in all cases a significant increase in ESR and in plasma SFMC with unrelated elevation of the fibrinogen level. Protamine sulphate added to whole blood with high ESR to final concentration 1 mg/ml of blood completely abolished the sedimentation of erythrocytes. A hypothesis is formulated according to which red cells interacting with SFMC increase their sedimentation rate.

Participation of Soluble Fibrin Monomer Complexes and Platelet Factor 4 in the Generalized Shwartzman Reaction

The generalized Shwartzman reaction was produced in rabbits by the typical way of 2 consecutive injections of Salmonella typhi endotoxin. Generalized Shwartzman reaction was also induced by “preparation” of the rabbits with epsilon-aminocaproic acid or mercuric chloride intoxication, followed by a single injection of the endotoxin. Significant impairment of blood fibrinolytic activity resulting from inhibition by endotoxin of a release of the kidney plasminogen activator, was demonstrated in the classical generalized Shwartzman reaction. Inhibition of fibrinolysis led to the accumulation of soluble fibrin monomer complexes in the circulation, detectable in plasma by protamine sulfate precipitation. It is postulated that hypercoagulability, regularly occurring in the generalized Shwartzman phenomen, is due to fibrinolysis inhibition. Endotoxin causes release of platelet factor 4 from rabbit blood platelets both in vitro and in vivo. This factor is thought to be responsible for nonenzymatic intravascular precipitation of fibrin from circulating soluble fibrin monomer complexes. Bilateral cortical necrosis in kidneys is due by fibrin deposition resulting from the disturbance in the equillibrium between blood clotting and fibrinolytic systems and the interaction of accumulated soluble fibrin monomer complexes with platelet factor 4.

An Antiproteolytic and Antifibrinolytic Preparation Obtained from the Potato by Means of Chromatography on SE-Sephadex C-50

A crude preparation of a proteolytic enzyme inhibitor from potatoes was purified by means of column chromatography with SE-Sephadex C-50 using a stepwise gradient of concentration and pH when eluting proteins from the column. The inhibitor preparation thus obtained is stable for a 28 day period of storage and resistant to the action of various physical and chemical factors harmful to the spatial structure of proteins. The potato protease inhibitor markedly inhibits the activity of trypsin, chymotrypsin, plasmin and alkaline proteases from Aspergillus flavus. The inhibition of pronase and a mixture of acid cellular proteases by this inhibitor is considerably less. Pepsin, cathepsin D, and collagenase are not affected by this inhibitor. The potato inhibitor has a marked inhibitory effect on plasmin fibrinolytic activity both in purified systems and in the plasma euglobulin fraction. It also protects the fibrinogen from the action of this enzyme. It does not, however, inhibit plasminogen activation under the influence of either streptokinase or urokinase.

The Hypercoagulability in Mercury Chloride Intoxicated Dogs

Experimental acute mercury chloride intoxication has been produced in the dog by subcutaneous injection of HgCl2 in a daily dose of 3 mg/kg of weight for 3 days. The following features of hypercoagulability of dog blood have been found: increase of fibrinogen level, increase of factors II and VII, shortening of the thrombin and prothrombin times, shortening of the thromboelastographic “r” and “k” values, increase of “ma” and “me” values, increase of platelet adhesiveness. On the other hand plastic clotting time was slightly prolonged.

It has been postulated that hypercoagulability in the dog during mercury chloride intoxication is caused by the increase of inactive clotting factors. This may be connected with disturbances in the plasma protein balance in nephrosis.

Release of Platelet Factor 4 in Vivo during Intravascular Coagulation and in Thrombotic States

Platelet factor 4 released from platelets into the circulating blood was determined using both the heparin thrombin time and paracoagulation methods. It has been found that thrombin injected intravenously into rabbits releases large amounts of this factor. Infusion of plasmin does not release this factor and this finding may be of importance for the differential diagnosis between disseminated intravascular clotting and primary fibrinolysis. PF4 is not released during the hyper coagulable condition induced by HgCl2 intoxication. Only small amounts of this factor are released after contact factor infusion.

A significant elevation of extraplatelet PF4 was found in 23 patients with fresh coronary thrombosis and in 9 patients with thrombophlebitis and thromboembolic complications.

The significance of the above findings for the pathogenesis, treatment and laboratory diagnosis of thrombotic diseases with particular reference to heparin tolerance test is discussed.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

In the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

The Fibrinolytic System in Patients with Right Ventricular Failure Treated with Novurit

It has been found that the activity of the fibrinolytic system is decreased in patients treated with Novurit. No changes were observed in patients treated with hydrochlorothiazide. Attention is drawn to the risk of administering organic mercurial diuretics to patients with a tendency toward hypercoagulability.

Fibrinolytic Activity of Tissue Sections of the Dog Kidney

A method for estimating fibrinolytic activity of the tissue sections has been worked out. This method consists in covering tissue sections with thin fibrin layers and in microscopic evaluation of their digestion. Using two types of fibrin layers: a) prepared from fibrinogen containing plasminogen, b) prepared from plasminogen free fibrinogen, it is possible to differentiate, whether the digestion is due to the plasminogen activator or to the active enzyme (plasmin).

Fibrinolytic activity of the section of dog kidney tissue has been investigated. Experiments were performed on normal kidneys and on kidneys damaged by the mercury chloride intoxication. Studying normal dog kidney it has been found that plasminogen activator is present in juxtaglomerular cells, macula densa and Goormaghtigh cells. It appears that the endothelial cells of the glomerular vessels contain, besides plasminogen activator, an active enzyme, probably plasmin. In the medullary portion of the section of normal kidney tissue no fibrinolytic activity has been found.

In dogs intoxicated with mercury chloride the plasminogen activator decreases in vascular endothelia but it completely disappears in the juxtaglomerular apparatus. The injury of the juxtaglomerular apparatus due to mercury chloride intoxication has been also found by routine histopatho-logical investigations.

It is suggested that the plasminogen activator, secreted by the kidney into the general circulation, orginates mainly in the juxtaglomerular cells.

Fibrinolysis and Fibrinogen Breakdown Products (Antithrombin VI) in Renal Venous Blood (RVB) in Dog

The authors investigated fibrinolytic system of renal venous blood (RVB) peripheral venous blood (PVB) in normal dogs and in those with kidney injury produced by mercury chloride. An increase of fibrinolytic activity as well as a decrease of the level of plasminogen and fibrinogen were found in RVB plasma of normal dogs. An inhibition of the fibrinolytic activity was found in intoxicated dogs in both RVB and PVB plasmas, followed by an increase of plasminogen and fibrinogen levels. The occurence of fibrinogen breakdown products, antithrombin VI, was demonstrated in RVB plasma of normal dogs. It does not appear in RVB plasma of intoxicated dogs.

On the basis of experimental results an important role of urokinase, secreted by the kidney into the general circulation is suggested as regards the maintenance of the coagulation and fibrinolysis balance in the organism as well as in the fibrinogen and plasminogen catabolism.

It has been also concluded that the antithrombin VI, formed in the kidney circulation is a natural inhibitor of blood coagulation appearing in physiological conditions.

Intravascular Coagulation and Fibrinolysis by Stapliylocoagiilase. Comparison with Thrombin

Intravascular clotting in rabbits after intravenous injection of 30 N.I.H. units of thrombin/kg and 5/mg/kg of staphylocoagulase were studied. Following determinations were made : clotting time, thrombin time, fibrinogen, factors V, VII, VIII, X, XI and XII, “true prothrombin”, two stage prothrombin, P-P test, prothrombin consumption, fibrinolysis in serum euglobulins, plasminogen, antithrombin III and VI, and coagulase reacting factor. Intravenous staphylocoagulase produced in rabbits precipitous drop of fibrinogen level in a very short time, which was not observed with the dose of thrombin used. Activity of staphylocoagulase in vivo was very much higher than of thrombin, as it could be expected on basis of the in vitro comparison. Together with defibrination caused by staphylocoagulase, fibrinogen breakdown products, identified as antithrombin VI, appear in plasma. There were no such changes observed when thrombin was used. Slight decrease of prothrombin and antithrombin III levels, together with a lack of significant changes in factors V, VII, VIII, X, XI and XII content, were observed after staphylocoagulase injection. Slight increase of CRF content in staphylo co agulase clotted plasma was noted. Fibrinolytic system was not activated during clotting process caused by staphylo-coagulase. Significance of the data obtained is discussed.

Fibrinolytic System in Hypotensive Patients; with a Special Reference to the Effect of Epsilon-Amino Caproic Acid (EACA)

An acceleration of euglobulin fibrinolysis and a slight decrease of plasminogen and of antiplasmin were found in idiopathic hypotensive patients. EACA administered orally in daily doses 0.1 g /kg of weight for 4 days produced both an inhibition of fibrinolysis and a significant rise in arterial blood pressure in 15 of 18 patients studied. It has been suggested that the pressure effect of EACA may be mediated by inhibiting plasminogen activation.

Fibrinolytic System in Patients with Hypertensive Cardiovascular Disease

The fibrinolytic system has been studied in 37 patients with essential hypertension, with arterial hypertension of various etiology (renal hypertension and hypertension with atherosclerosis). It has been found that in all these patients euglobulin fibrinolysis is inhibited and fibrinogen, factor VIII, plasminogen, plasminogen proactivator and antiplasmin increase considerably.

On the basis of the above findings and other literature data, the authors present a hypothesis that the fibrinolytic system is involved in the regulation of arterial blood pressure and that the impairment of plasminogen activator production in the renal tissue is one of the contributory factors in the development of arterial hypertension.

Turnover of 131I-Fibrinogen in Mercury Chloride Intoxicated Dogs

The turnover of 131I-fibrinogen, studied in 15 normal dogs, amounted on the average to 2.6 days. The fibrinogen level considerably increased but the biological half-life time of 131I-fibrinogen was significantly shorter in mercury chloride intoxicated dogs, particularly in the first phase of intoxication.

It has been concluded that the fibrinolytic enzymes connected with kidney and depleted in intoxicated dogs are not essential for the fibrinogen catabolism. The elevation of fibrinogen in mercury chloride intoxication is not directly caused by the inhibition of fibrinolytic enzymes.

Possible explanations of the accelerated turnover of fibrinogen in HgCl2 treated dogs were discussed.

The Effect of Chronic Administration of Lathyrogen (Beta-Aminopropionitrile) on Blood Clotting and Fibrinolytic System in Rabbits

The effect of chronic intoxication of rabbits with beta-aminopropionitrile on blood clotting and fibrinolysis was studied.

The increase of clotting time of whole blood and recalcified plasma accompanied with the decrease of factor IX, XI and XIII level were observed. On the other hand the significant increase of fibrinogen content and soluble complexes of fibrin monomers level was found.

A deep inhibition of fibrinolytic activity of plasma was stated. The decrease of thromboplastic and fibrinolytic activity of saline extracts of some internal organs was also observed. The mechanism of above described changes and their significance in pathology are discussed.

Peptide inhibitors of plasmin

Seven peptides of the general formula A-Phe-Lys-X or A-Phe-NH-(CH2)5-NH2 where A = Glp or Ala, X = -OH, -NHC7H15 or -OC7H15 were obtained. The peptide H-Ala-Phe-Lys-NHC7H15 markedly inhibits the fibrinolytic activity of plasmin. The antifibrinolytic activity of the peptide Glp-Phe-Lys-OC7H15 is similar to EACA. The both peptides only slightly activate the caseinolytic activity of plasmin.

Lactacystin inhibits cathepsin A activity in melanoma cell lines

We describe the inhibitory effect of the proteasome inhibitor, lactacystin, on cathepsin A activity in murine melanoma cell lines. In vitro lactacystin metabolite, beta-lactone, at a concentration of 1 microM, significantly suppressed cathepsin A activity in B78 melanoma cell lysates by about 50%. Exposure of three murine melanoma cell lines with different metastatic potential to lactacystin at a concentration of 5 microM for 6 h caused a significant reduction in the carboxypeptidase activity of this enzyme, while the inhibitory activity remained unchanged for at least 12 h. Other proteasome-specific inhibitors, e.g. epoxomicin and N-benzyloxycarbonyl-Ile-Glu(O-tert-Bu)-Ala-leucinal (PSI) at a concentration of 1 microM did not affect cathepsin A activity in melanoma cell line lysates. These data support our previous proposal that lactacystin is not a specific inhibitor of the proteasome. Since cathepsin A is also a tumor-associated enzyme, further research is needed to clarify its role and the significance of its inhibition by lactacystin in tumor biology.

Separation of cathepsin A-like enzyme and the proteasome: evidence that lactacystin/beta-lactone is not a specific inhibitor of the proteasome

Previous studies have described a human platelet cathepsin A-like enzyme with a number of similarities to the "acidic" and "neutral" chymotrypsin-like activities of the proteasome. This includes its strong inhibition by the highly specific proteasome inhibitor Lactacystin/beta-lactone, suggesting that either the Cbz-Phe-Ala-hydrolyzing activity attributed to cathepsin A was due to the chymotrypsin-like activity of the proteasome or that lactacystin was not a specific inhibitor of the proteasome. In the present study we discard the first possibility on the basis of the following findings: (a) human platelet cathepsin A, unlike proteasome, binds to concanavalin A, and does not bind to Heparin-Sepharose at pH 7.4; (b) neither the chymotrypsin-like activity of the proteasome, nor proteasome antigens are detected in the cathepsin A preparation; (c) purified proteasome does not exhibit Cbz-Phe-Ala-hydrolyzing activity; (d) Z-lle-Glu-(Ot-Bu)Ala-leucinal (PSI), a compound that selectively inhibits the chymotrypsin-like activity of the proteasome at a concentration of 10 microM has no inhibitory effect on the carboxypeptidase activity of cathepsin A; (e) cathepsin A, free of the proteasome, is completely inhibited by micromolar concentrations of lactacystin/beta-lactone. It is therefore concluded that lactacystin/beta-lactone is not a specific inhibitor of the proteasome.

Inhibitors of pepsin, trypsin and chymotrypsin in seeds of plants consumed by humans and animals. I. Evaluation of pepsin, trypsin, and chymotrypsin inhibitors activity in seeds of 26 plant species

Antipepsin, antitrypsin and antichymotrypsin activity was determined in seed extracts of 26 plants consumed by humans and animals (small bean, broad bean, pumpkin, kidney bean, charlock, pea, buckwheat, barley, maize, flax, lupine, poppy, almond, peanut, hazel, walnut, oat, millet, wheat, rice, rape, sunflower, lentils soya bean, vetch, rye). Antipepsin activity is found in the seeds of small bean, pumpkin, flax, peanut, walnut, oat, wheat, sunflower, lentils and soya bean. Antitrypsin and antichymotrypsin activities are of different intensity in seed extracts of all examined plants.

The influence of epsilon-aminocaproic acid derivatives on the anticoagulant activity of heparin

Derivatives of epsilon-aminocaproic acid with antifibrinolytic activity, at low concentration, do not influence the anticoagulant activity of heparin under the heparin-thrombin test conditions. At concentrations higher than 0.002 M tested compounds slightly enhance the anticoagulant action of heparin.

Effects of epsilon-aminocaproylaminoacids on prothrombin activation and thrombin activity

Influence of four epsilon-aminocaproylaminoacids on prothrombin activation and thrombin activity was examined. Only epsilon-aminocaproylnorleucine markedly inhibited the prothrombin activation in an extrinsic system.

Activity of liver proteases in experimental methanol intoxication

Intoxication of rats with methanol (1.5 and 3.0 g/kg body weight) led to a significant, time- and dose-dependent decrease in the activities of cathepsins A, B and C, while the activity of cathepsin D was unaffected. The decrease was associated with a different partial release of individual cathepsins to the post-lysosomal fraction.

Prolidase activity and beta 1 integrin expression in moderately and poorly differentiated lung adenocarcinomas

Primary human lung adenocarcinomas were divided into two groups according to the degree of histologic differentiation: G2-moderately and G3-poorly differentiated tumors. Each group was compared with normal lung tissue in respect to prolidase activity, its ability to interact with specific antibody, free proline and beta 1 integrin subunit content as well as ability of beta 1 integrin subunit to interact with specific antibody. It was found that prolidase activity in lung adenocarcinomas G3, was significantly elevated in comparison to normal lung tissue. In lung adenocarcinoma G2 no significant changes in the enzyme activity were observed. Increase in the enzyme activity was accompanied by increase of free proline content in the tissues. The western blot analysis revealed that prolidase of lung adenocarcinomas is identical to prolidase originated in control lung tissue. It was noticed that elevated activity of prolidase in adenocarcinomas G3 was accompanied by its high expression. In respect to beta 1 integrin expression, known to play an important role in metastasis, no difference was found between adenocarcinoma groups and the control lung tissue. The presented data suggest that the level of prolidase activity in lung adenocarcinoma may serve as a more sensitive marker for the histologic degree of malignancy, than the level of beta 1 integrin expression.

Plasminogen activators and plasmin in lung cancer

Urokinase plasminogen activator and plasmin contribute to detach neoplastic cells from solid tumor and facilitate the movement of these cells through interstitium and capillary walls as well as infiltration of the surrounding structures. Plasminogen activators inhibitors fulfill a regulatory function in these processes. Determining activity and concentration, finding subcellular, cellular and zonal localization of every component of plasminogen activation system has diagnostic and prognostic importance in different lung cancer types.

Proteolytic enzymes in proliferation and neoplastic metastases formation

Metalloproteases, plasminogen urokinase activator, plasmin and cathepsins enable the expansion of neoplastic tumors, leading to metastases formation. They cause neoplastic cells to detach from tumor, facilitate cell movement, implantation and participate in tumor vascularization. The regulation of these processes is accomplished during the synthesis and activation of proenzymes. Enzyme activity control is realized by their bonds with cellular membranes, and inhibitor action.

Activity of liver proteases in experimental methanol intoxication

Intoxication of rats with methanol (1.5 and 3.0 g/kg body weight) led to a significant, time- and dose-dependent decrease in the activities of cathepsins A, B and C, while the activity of cathepsin D was unaffected. The decrease was associated with a different partial release of individual cathepsins to the post-lysosomal fraction.

Lactacystin, a specific inhibitor of the proteasome, inhibits human platelet lysosomal cathepsin A-like enzyme

Lactacystin, the most specific inhibitor of the proteasome, strongly inhibited at pH 5.5 the activity of human platelet lysosomal cathepsin A-like enzyme. At a concentration as low as 1-5 microM it almost completely decreased the hydrolysis rate of cathepsin A specific substrates: Cbz-Phe-Ala and FA-Phe-Phe. This inhibition was probably due to the lactacystin intermediate beta-lactone formed during 10 min hydrolysis at pH 8.0 since nonhydrolyzed inhibitor did not affect cathepsin A activity. Basing on similarities in the inhibitor sensitivity, pH optimum, and substrate preferences it is suggested that the cathepsin A-like activity may be involved in chymotrypsin-like activity of the proteasome.

Tripeptide methylketones: synthesis and antiplasmin activity

A series of tripeptide methylketones with C-terminal lysine was obtained via Dakin-West method and tested for their antiplasmin activity with the use of antifibrinolytic and antiamidolytic tests. The tripeptide methylketones has been found to inhibit plasmin, however with much lower potency than respective aldehydes.

Synthesis and activity of N epsilon-aminocaproyl-L-norleucine derivatives

Five new derivatives of epsilon-aminocaproyl-L-norleucine were synthesized. Antifibrinolytic and anticaseinolytic activities were tested. All tested compounds were inhibitors of plasmin.

Influence of dipeptide derivatives of S-substituted cysteines on the time of fibrinolysis

Amino acids containing sulphur, dipeptide derivatives of methionine and S-substituted derivatives of cysteine are potent antifibrinolytic agents. The structural moiety of the substances responsible for the effect on the clot formation is not known. Present study was undertaken in order to evaluate the effect of some analogues of dipeptides containing S-substituted derivatives of cysteine with the formula A-Cys(S-X)-Y (where A-amino acid, X-benzyl, butyl, hexyl, nonyl and Y-OH or OMe) on clot dissolution under the antifibrinolytic test conditions. It has been found that dipeptide derivatives of S-substituted cysteine (except benzyl derivative) at low concentration evoke antifibrynolytic activity, while at high concentration they prevent clot formation. The results suggest that antifibrinolytic activity of tested compounds at low concentration may be due to the formation of antifibrinolitycally active conformation, while high concentration overcome the effect.

Synthesis and activity of N alpha-(epsilon-aminocaproyl)-alanines and N epsilon-(epsilon-aminocaproyl)-caproic acid

Four new dipeptides containing epsilon-aminocaproic acid were synthesized. Antibrinolytic, antiacaseinolytic activity and influence on activation of plasminogen by streptokinase were tested.

Cathepsin D activity and protein degradation products in organs and blood during experimental declamping shock

Aortic cross-clamping in dogs for 60 min causes an increase in cathepsin D activity in the kidney, liver, lung, heart, skeletal muscle and the blood serum. It causes no changes in the content of protein and its degradation products of the examined organs, apart from the lungs, where the above parameters are higher. The intensity of the observed changes in the kidney and other organs does not depend on the level of aortic cross-clamping (above or below renal arteries).

The effect of activated alveolar macrophages on experimental lung emphysema development. I. Protease and antiprotease activities in the culture medium of alveolar macrophages

Aim of the present study was to evaluate cathepsin D, base protease, antiplasmin, antitrypsin and antichymotrypsin activities and protein content in the 24h culture medium of the alveolar macrophages (AM) deriving from the rats treated BCG-vaccine and from rats with papain-induced emphysema. In the culture medium of cells isolated from the rats which were given BCG or papain and BCG+papain we observed an increase of base protease activity and a decrease of cathepsin D activity comparing with control group. Increased antitrypsin activity in BCG and BCG+papain-treated rats and decreased antitrypsin activity in papain-treated rats were observed. There were not significant differences in antiplasmin and antichymotrypsin activities between examined groups. The obtained results indicate that activated pulmonary macrophages are one of the sources of the protease-antiprotease intraalveolar imbalance. However, increased production of proteolytic enzymes may not be the only factor responsible for the progression of lung emphysema in BCG-treated rats.

Activity of membrane, cytosol and lysosome enzymes in organs and blood serum during declamping shock

The aim of the study was to evaluate the enzyme activity of cellular membranes (GGT), cytosol (ALT, AST) and lysosome (AP, AcP) in the cytosol, whole homogenate and blood serum during declamping shock, following release of abdominal aorta cross-clamping. The aorta was clamped for 60 minutes. An increase in GGT, AP and AcP activities in the cytosol and whole homogenate of the renal cortex, renal medulla, liver, lung, heart and the skeletal muscle occurs after declamping. Rise in the enzymatic activity, especially of acid phosphatase is higher when the aorta above renal arteries was clamped. However, its activity in the blood serum remains unchanged. Alterations in the distribution and the activity of the studied enzymes may indicate that aortic clamping damages the endoplasmic reticulum and lysosomal membranes. Yet, cellular membranes preserve their structural and functional integrity.

Complexoproductive and antiheparin properties of low density lipoproteins (LDL). III. Interaction of low density lipoproteins (LDL) with synthetic polyanionic compounds

Low density lipoprotein (LDL) form insoluble complex bonds with polymetacrylic and polyvinylsulphonic acids in the presence of calcium chloride. Quantity of arising complexes depends on the concentrations of LDL, acids and calcium chloride and on pH. These complexes dissociate solutions of sodium chloride, urea and guanidine hydrochloride.

Complexoproductive and antiheparin properties of low density lipoproteins (LDL). V. Optimum conditions of the coagulation method to determine antiheparin activity in the blood plasma

It was found that storing the plasma in the temperature 0 degree C, 4 degrees C and 20 degrees C and especially in 37 degrees C increases pH and decreases antiheparin activity estimated by the heparin-thrombin test. Measurements of the heparin-thrombin time should be carried out directly after obtaining the plasma or after reducing the plasma to pH 7.40.

[Anti-heparin activity of plasma with various low density lipoprotein content]

Anti-heparin activity correlated with LDL concentration in the plasma. Blood plasma of women in labour is characterized by the high antiheparin activity and low LDL levels. Anti-heparin activity is low and LDL levels are low in blood plasma in childhood. An effect of other factors neutralizing heparin (e.g. fibrinogen, platelet factor 4, acid alpha 1-glycoprotein, globulins, basic proteins) and differences of anti-thrombin III on plasma anti-heparin activity has been excluded. Neutralization of heparin anticoagulation activity by LDL is of clinical value. Blood LDL level should be considered, while heparin therapeutical doses are under scrutiny.

Low molecular organic inactivators in differentiating organ origin of alpha-amylase in humans. Part I

Alpha-amylases derived from pancreatic juice, saliva and granulocytes show different sensitivity to the low molecular organic inactivators. Pancreatic alpha-amylase is more susceptible to inhibitory activity of d-glyceraldehyde and d-mannitol and glycerol in comparison to alpha-amylase from saliva and granulocytes. Iodoacetate and urea exhibited inhibitory activity against granulocytic alpha-amylase and only a minute inactivation of salivary and pancreatic alpha-amylases was found. The most effective inhibition against all tested alpha-amylases was noted with dihydroxyacetone. We should stress, no evident differences were noted in the degree of sensitivity to this inactivator of the tested enzymes. The presumable mechanism of the inactivation of alpha-amylases with low molecular organic inactivators is briefly discussed. The procedure for the differentiation of organ origin of alpha-amylases is suggested.

Inhibitory effect of ethanol and acetaldehyde on the amidolytic activity of trypsin and chymotrypsin

Ethanol and in higher degree acetaldehyde displayed inhibitory effect directed against amidolytic activity of trypsin and chymotrypsin. The decrease of the activity of both enzymes is related to the concentration of these compounds. The rate of inhibition of amidolytic activity of chymotrypsin with both reagents is more evident in comparison to trypsin.