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Biomedical subjects

M Gacko

Publications and source records attributed to M Gacko.

At least 37 records · Page 2Linked to original sources

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.

Animals↗

Lysosomal cysteine proteinases and their significance in pathology.

The lysosomal cysteine proteinases are synthesized in a form of pre-proenzymes. They are submitted to posttranslational glycosylation and phosphorylation. These modifications make possible transport the modified proteins into Golgi apparatus and into lysosomes. Some disturbances of transport which occur mainly in tumour cells result in an increase of these enzymes activities in cytosol and in intercellular compartment. The activity of cysteine proteinases is regulated by specific inhibitors (cystatin, kininogen) which exist in some tissues and body fluids. The evaluation of activity and concentration of proteinases and inhibitors is important in clinical diagnostics.

Amino Acid Sequence↗

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.

Fibrinolysin↗

Biological and diagnostic role of cathepsin D.

Biosynthesis, posttranslating modifications, intracellular transport and activation of procathepsin D are discussed. Active cathepsin D evokes degradation of cellular and extracellular proteins and it also activates proenzymes, prohormones and growth factors and inactivates their active forms. Impairment of lysosomes in hypoxia or necrosis evokes transition of cathepsin D to cytosol and body fluids. Increase of cathepsin D content in cytosol also evokes enhancement of the synthesis rate observed among others, in neoplastic tissues and regenerating organs. Increase of cathepsin D content and activity in cytosol and blood serum is of essential diagnostic and prognostic importance in some pathologic conditions.

Animals↗

Cancer procoagulant--CP.

A review of literature concerning cancer procoagulant (CP) has been carried out. This procoagulant directly activates coagulation factor X to factor Xa. Possibilities of utilising determinations of this activator in diagnostics and prognostics of the cancerous disease are discussed.

Animals↗

Tissue factor pathway inhibitor (TFPI).

Tissue factor pathway inhibitor (TFPI) is a plasma proteinase inhibitor. It is a 42 kD glycoprotein that consists of 276 amino acid residues which sequence is known. TFPI is synthesized by vascular endothelial cells and part of it is associated with glycosaminoglycans of these cells. In blood TFPI is found in a free-form (active) and in an associated with lipoprotein form (nonactive). TFPI directly inhibits activated factor Xa and then factor VIIa/TF complex. Decreasing TFPI activity facilitates an activation of blood coagulation and fibrin forming, increasing TFPI activity inhibits these processes.

Blood Coagulation Disorders↗

[Tissue factor pathway inhibitor (TFPI) and its role in pathology].

Tissue factor pathway inhibitor (TFPI) is an important regulator of blood coagulation. It was described as antyconwertin (AC), extrinsic pathway inhibitor (EPI) and lipoprotein-associated coagulation inhibitor (LACI). TFPI is a glycoprotein, which is mainly synthesized by vascular endothelial cells. The concentration of this enzyme in plasma is low (100 ng/ml). TFPI inhibits activity of factor Xa and complex FVIIa/TF. Changes TFPI activity play an important role in coagulation disorders and presently the function of TFPI in various kinds of diseases is discussed.

Amino Acid Sequence↗

[Matrix metalloproteases (MMPS)].

Matrix metalloproteases (MMPs) are synthesized in the form proenzymes. They are activated in the process of limited proteolysis and non-enzymatically by active forms of oxygen. Activity of these enzymes is controlled by tissue inhibitors of metalloproteases (TIMPs).

Amino Acid Sequence↗

Disturbances of hemostasis during declamping shock.

The aorta, above or below renal arteries was clamped for 60 minutes, in a canine model. The blood was taken for testing from above the aorta bifurcation before clamping, after 30 minutes of its duration, directly after declamping and every 30 minute during next 4 hours. Irrespective of clamping level, the platelet count, clot retraction and prothrombin consumption do not undergo significant changes. However, the activity of platelet factor 4 is increased. Prothrombin time, recalcination time, kaolin-kephalin time and the activities of factors V, VII, XI and XII do not differ as well. Thrombin time is prolonged and antithrombin III activity is reduced. Euglobulin fibrinolysis time undergoes prolongation and antiplasmin content is increased. The observed changes show a variable tendency, regardless of clamping level and increase with the passage of experiment time. An increase in the coagulation activity and a decrease in the fibrinolytic activity of the blood plasma may be a resultant of the changes. Finally it may promote thrombus formation and indicates the preventive use of heparin.

Animals↗

Hemostatic activity of organs in declamping shock.

The aim of the study was to determine the haemostatic components activity of organs in declamping shock. The abdominal aorta was cross-clamped below or above renal arteries. No significant changes in tromboplastic and antithrombin activities were found in the kidney, liver, lung, heart and skeletal muscle. Renal cortex and medulla as well as the lungs show higher plasminogen activator activity and considerably higher antiplasmin activity. Diminished fibrinolysis in the kidney and the lung may promote thrombotic complications.

Animals↗

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.

Acid Phosphatase↗

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).

Animals↗

Collagen, elastin and glycosaminoglycans in aortic aneurysms.

The walls of human abdominal aortas and atherosclerosis-induced aneurysms contain similar amounts of collagen. The quantitative ratio between collagens of various types of this protein does not differ significantly either, whereas solubility of the collagen in aneurysmal wall and its susceptibility to the action of EDTA are distinctly decreased. In contrast with collagen, the amount of elastin in aneurysms is significantly lower. Total amount of glycosaminoglycans slightly decreased as compared with that of normal tissue, but the ratio of particular compounds varies. The percentage of chondroitin sulphate is increased and that of heparan sulphate significantly decreased. The significance of these changes in pathogenesis of aneurysms is discussed.

Adult↗