PubMed Health⌕ Search

Biomedical subjects

G Blaskó

Publications and source records attributed to G Blaskó.

At least 55 records · Page 3Linked to original sources
PubMed1982

Distinction of two pathologic antithrombin III molecules: antithrombin III "Aalborg' and antithrombin III "Budapest'.

Plasma from two different thrombophilic families with functional inherited antithrombin III deficiency, i.e., with low antithrombin III activity but normal immunoreactive antithrombin III concentration, were investigated simultaneously in the same laboratory. The experiments (thrombin and Factor Xa inactivation, heparin affinity chromatography, modified two dimensional immunoelectrophoresis and gel filtration) showed a distinct difference between the two antithrombin III anomalies. The antithrombin III "Aalborg' had decreased thrombininactivating activity but normal Factor Xa-inactivating activity. The heparin affinity and the molecule weight are normal. The antithrombin III "Budapest' displays a more profound abnormality with pathologic thrombin and Factor Xa inactivation, decreased heparin affinity and abnormal molecular weight.

Antithrombin III↗
PubMed1980

Heterogeneity of the "classical" antithrombin III deficiency.

We investigated two thrombophilic families with the "classical" type of antithrombin III deficiency, i.e., with a low antithrombin III level measured both by immunochemical and functional methods. We obtained different antithrombin III patterns in the plasma of the affected members of the two families with the modified two dimensional immunoelectrophoresis method (heparin in agarose). In one family, the electrophoretic mobility of the antithrombin III is identical with that of normal antithrombin III. In the other, the antithrombin III displayed a decreased electrophoretic mobility in the heparinized agarose gel. The relatively low affinity of this antithrombin III to heparin could be directly proved by the heparin-agarose affinity chromatography, too. These two different antithrombin III patterns were observed by other investigators at different families as well. On the basis of our simultaneous observations of these two families we propose a classification of the inherited congenital antithrombin III deficiencies.

Adolescent↗
PubMed1979

Decreased heparin sensitivity of cyclohexanedione-modified factor Xa.

Modification of 12 arginine residues of bovine Factor Xa with 1,2-cyclohexanedione has resulted in a decrease in heparin sensitivity of the reaction between enzyme and antithrombin-III, whereas the antithrombin-III sensitivity of modified Factor Xa was only slightly affected. It is suggested that heparin accelerates the Factor Xa-antithrombin-III reaction by interacting with Factor Xa.

Animals↗
PubMed1979

Effects of PGI2 on the inactivation of thrombin, factor Xa, and plasmin by antithrombin-III and heparin.

The influence of PGI2 on the activity and on the inactivation of enzymes participating in blood coagulation (thrombin and Factor Xa) and fibrinolysis (plasmin) were investigated. According to the results PGI2 has no effect on the activity of Factor Xa and plasmin nor on the inactivation of these enzymes by antithrombin-III in the absence and presence of heparin at a concentration of PGI2 up to 400 micrograms/ml. An acceleration of the inactivation of thrombin by antithormbin-III was found in the presence of PGI2 within a concentration of 100-400 micrograms/ml without any effect on the heparin-accelerated inactivation of thrombin by antithrombin. We got similar results using clotting tests for the assay and the application of synthetic substrate for thrombin. This inactivation-accelerating effect of PGI2 on thrombin was only demonstratable at a concentration five magnitudes higher than that of the anti-aggregation effect on platelets.

Antithrombin III↗
PubMed1979

Effect of hypoxia on the development of Drosophila melanogaster (Meigen).

Specimens of Oregon-R Drosophila melanogaster (Meigen) were bred in a defined sexual ratio in test chambers under different partial pressures of O2. In the gas mixture of 5--7% O2 plus 93--95% N2, the number of ovules dropped to nearly half even in the first generation, the time period of each development stage was considerably extended, and the size of the larvae decreased to a fraction of that of the controls. In the groups kept in a mixture of 10--12% O2 plus 88--90% N2, the same changes took place at a much slower rate, through several generations.

Aerospace Medicine↗
PubMed1979

The effect of some pyrimido-pyrimidine derivatives on blood coagulation and platelet aggregation.

Two pyrimido-pyrimidine derivatives, Chinoin 105 and Chinoin 123, respectively, were investigated with respect to the inhibition potency on platelet aggregation. It was shown that Chinoin 105 is a powerful inhibitor of aggregation of thrombocytes without effect on routine coagulation parameters in vitro. Chinoin 123 has a moderately inhibitory effect on the investigated reactions. An additive effect of Chinoin 105 to the inhibitory potential of PGE1 on platelet aggregation was proven.

Adenosine Diphosphate↗
PubMed1978

Air reoxidation and reactivation of reduced thrombin.

About 80% of thrombin was inactivated after 50 minutes chemical reduction at 22 degrees C in a reaction mixture containing o.1 M mercaptoethanol and 2.6 M urea. The reduced protein was spontaneously reoxidated in air at 22 degrees C in 30--60 minutes. The reoxidation of disulphide bonds in thrombin led to partial reactivation of the enzyme. Recovery of thrombin activity after oxidation ranged from 0 to 60% according to the conditions of reoxidation in air. Heparin and copper ion increased the rate of reactivation, whereas in the presence of 10 mM iodoacetamide there was no reactivation.

Air↗
PubMed1977

Inactivation of alpha- and beta-thrombin by antithrombin-III, alpha 2-macroglobulin and alpha 1-proteinase inhibitor.

Inactivation of alpha- and beta-thrombin by alpha 2-macroglobulin, by alpha 1-proteinase inhibitor and by antithrombin-III and heparin was studied. The amount of alpha- and beta-thrombin inactivated by antithrombin-III was proportional to the concentration of the inhibitor, but the inactivation rates of the two forms of thrombin were different. Heparin facilitated complex-formation between alpha-thrombin and antithrombin-III, whereas inactivation of beta-thrombin by antithrombin was only slightly influenced, even at a heparin concentration two orders of magnitude higher. alpha 2-Macroglobulin inhibited both alpha- and beta-thrombin activity similarly, i.e. the amount of alpha- and beta-thrombin inactivated as well as the rates of their inhibition were the same. alpha 1-Proteinase inhibitor also formed a complex with alpha- and beta-thrombin, similarly to antithrombin-III, although the inactivation of the enzyme needed high inhibitor concentration and long incubation time. These results suggest that the inactivation of beta-thrombin, if it occurs in the plasma, is also controlled by plasma inhibitors.

Antithrombins↗
PubMed1977

Effect of collagen on thrombin inactivation by antithrombin-III and heparin.

Thrombin inactivation by antithrombin-III and heparin has been found to decrease in the presence of collagen, whereas thrombin activity and the rate of thrombin inactivation by antithrombin-III alone are not affected. Albumin, at the same concentration as collagen, does not influence either thrombin activity or thrombin inactivation by antithrombin-III or by antithrombin-III plus heparin.

Animals↗
PubMed1977

Some properties of human progressive antithrombin.

The effect of some mono- and divalent cations was examined on thrombin--antithrombin reaction in vitro. It was found that 0--0.1 M sodium- or potassium chloride did not affect either thrombin or antithrombin activity; at higher concentrations thrombin activity decreased. Calcium chloride as well as magnesium chloride at concentrations from 0 to 0.5 M increased enzyme activity, whereas at higher concentrations the activity decreased. Thrombin inactivation by antithrombin was also accelerated at calcium or magnesium chloride concentrations above 0.04 M. Antithrombin was inactivated at pH 7.3 at 65 degrees C in some minutes and heparin failed to protect it against heat denaturation. Thrombin inactivation by antithrombin did not proceed at 0 degrees C in 60 min, but the interaction between thrombin and antithrombin was facilitated in the presence of heparin.

Antithrombin III↗
PubMed1976

Inactivation of alpha- and beta- thrombin by antithrombin-III and heparin.

Inactivation of alpha- and beta-thrombin by antithrombin-III and heparin was studied, since it had been suggested that two forms of thrombin exist with respect to heparin sensitivity (Machovich 1975b). It was found that the inactivation rates of alpha- and beta-thrombin by antithrombin were different, namely alpha-thrombin was more sensitive to antithrombin than beta-thrombin. Heparin facilitated the complex formation between alpha-thrombin and antithrombin-III, whereas beta-thrombin inactivation was only slightly affected. Furthermore, heparin protected alpha-thrombin against the inactivating effect of heat, while beta-thrombin lost its activity during the heat treatment. These findings suggest that the formation of beta-thrombin in blood circulation may have an important role in thrombosis predisposition.

Alpha-Globulins↗
PubMed1975

Action of heparin on thrombin-antithrombin reaction.

Thrombin partially purified from bovine plasma can be inactivated at 60 degress C. In the presence of 10 units of heparin the extent of inactivation decreases. When thrombin and heparin are mixed and incubated for 5 min at 0 degrees C before gel filtration on Sephadex G-200, thrombin with heparin is eluted prior to either thrombin or heparin laone. These data suggest a complex formation between thrombin and heparin. Immobilized heparin binds thrombin. The enzyme can be eluted with 0.05 M Tris-HCl buffer, pH 7.3, containing an ion mixture of Na+, K+ and Ca2+ at 73, 3 and 11 mM, respectively, at 0 degrees C and with 0.05 M Tris-HCl buffer, pH 7.3, containing 0.5 M NaCl at 20 degrees C. During the same chromatographic procedure, antithrombin-III (heparin cofactor) partially purified from human plasma is eluted with 0.05 M Tris-HCl buffer, pH 7.3, at 0 degrees C as well as 20 degrees C. Although, as described in the literature, heparin binds to antithrombin, our findings suggest another possibility, i.e. that the binding of heparin to thrombin induces a conformational change in the enzyme facilitating a complex formation between thrombin and antithrombin-III.

Antithrombin III↗
PubMed1974

Abnormal antithrombin III (antithrombin III "Budapest") as a cause of a familial thrombophilia.

A family with a high incidence of spontaneous thromboembolism has been investigated and those members affected were found to have significantly depressed levels of plasma and serum heparin cofactor activity; i.e., antithrombin III and anti-Xa activity. Further studies revealed that despite a marked diminution of antithrombin III activity in these patients measurement of antithrombin III by immunological techniques showed the levels to be normal. It is concluded that this anomaly represents a defect in the synthesis of the antithrombin III molecule. The abnormality appeared to be inherited but the mode of inheritance could not be determined with the available data.

Adsorption↗