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Biomedical subjects

V V Ryvniak

Publications and source records attributed to V V Ryvniak.

At least 19 recordsLinked to original sources
PubMed1992

[The electron-histochemical detection of the activity of thiol proteinases in normal and cirrhotically altered liver].

The distribution co-activity of thiol proteinases (cathepsin B and cathepsin H) was investigated in normal and cirrhotic liver by the electron-cytochemical method. The reaction product was localized on lysosomes of Kupffer's cells, hepatocytes, endotheliocytes and fibroblasts. Extracellular activity of thiol proteinases was revealed in normal as well as in cirrhotic liver. The reaction product was situated on collagen fibrils near hepatocytes and connective tissue cells. The results evidence that besides participation in intracellular degradation of different proteins, thiol proteinases are secreted by hepatocytes and connective tissue cells of the liver to the intercellular space and can take part in extracellular collagen resorption.

Animals↗
PubMed1990

[Surgical interventions in severe experimental injuries of the liver].

The authors generalize experience in experimental study of some surgical interventions in severe injuries to the liver. A total of 104 operations were carried out on 52 animals. The efficacy of gauze tamponade with the use of absorbable hemostatics is determined. The methods for applying a vascular suture in injury to the efferent hepatic veins was studied on 12 human cadavers and 10 dogs. It is concluded that gauze +hepatic tamponade is expedient, mainly in coagulopathy in which subsequent relaparotomy is necessary (optimal terms 1-3 days) and the accomplishment of final hemostasis.

Animals↗
PubMed1990

[Intracellular and extracellular activity of cathepsin D in the liver in cirrhosis and its involution].

The distribution of cathepsin D in liver with CCl4 induced cirrhosis and its involution in rats was investigated by ultrastructural cytochemistry. Besides intracellular, it was revealed the extracellular activity of cathepsin D. The reaction product was on collagen fibers near the hepatocytes and connective tissue cells as well as on the hepatocytes microvilli and on the outside part of cellular membrane of connective tissue cells (macrophage, fibroblast, Ito cells). Hence the source of extracellular cathepsin D in liver are the parenchymatous as well as nonparenchymal cell elements. The results testify that under the cirrhosis and its involution, the cathepsin D takes part in intracellular proteolysis and is secreted by hepatocytes and connective tissue cells in the intracellular space; it also takes part in extracellular catabolism of connective tissue.

Animals↗
PubMed1989

[Methods of hemostasis and hepatectomy in injuries of the liver].

In 77 animals, 154 operations of gauze tamponade of a hepatic wound with the use of hemostatic preparations were performed. On the 12 human cadavers and 10 dogs, the technique of placing a vascular suture in injuries to efferent hepatic veins was tried. The dynamics of acid phosphatase activity as a criterium of hepatic cirrhosis involution after partial hepatectomy in 30 albino mice was traced. The use of gauze tamponade of a hepatic wound with the performance of relaparotomy (optimal time: within 1-3 days) and definitive hemostasis is expedient, mainly, in coagulopathy. No differences in the regression of hepatic cirrhosis in partial resection of the liver and without it were revealed.

Animals↗
PubMed1988

[Dynamics of acid phosphatase activity in the liver in the process of involution of cirrhosis].

Changes in the total activity of acid phosphatase in the liver as well as changes in the enzyme activity in hepatocytes and connective tissue cells of fibrosis layers were investigated, using quantitative histochemical method, in the process of mouse cirrhosis involution. After discontinuation of CCl4 injection, the animals with cirrhosis were divided into two groups. In the first group the resection of the left lobe of the liver was performed. The animals of the second group were not subject to operation. The results demonstrate that there is a close correlation between lysosomal hydrolase activity of hepatocytes and connective tissue cells of the liver and collagen resorption during cirrhosis involution. The most intensive lysis of collagen takes place within the first three weeks of cirrhosis involution in both experimental groups. Partial resection in cirrhosis has no significant effect on the changes and level of total activity of lysosomal hydrolase enzymes in the liver during cirrhosis involution.

Acid Phosphatase↗
PubMed1987

[Mechanisms of collagen resorption during the involution of liver cirrhosis].

Extracellular and intracellular mechanisms of collagen resorption were demonstrated electron-microscopically on white mice with involution of hepatic cirrhosis. Lysosomal enzymes (released into the extracellular space by exocytosis from hepatocytes and connective tissue cells) actively participate in the extracellular collagen lysis. Phagocytosis and intracellular collagen resorption by hepatocytes, macrophages (stellate reticuloendotheliocytes) and fibroblasts occur simultaneously with the extracellular collagen lysis also due to the activity of lysosomal collagenolytic enzymes.

Absorption↗
PubMed1986

[Extracellular breakdown of collagen as affected by lysosomal enzymes during the involution of liver cirrhosis].

Electron microscopy and electron histochemistry (exposure to acid phosphatase) were used to study the mechanisms of extracellular degradation of collagen in the liver during involution of experimental cirrhosis. The following results were obtained: extracellular secretion of lysosomal enzymes from hepatocytes and connective tissue cells takes place in liver cirrhosis and its involution; partial hepatectomy during liver cirrhosis stimulates the activity of acid phosphatase in the liver cells; the lysosomal enzymes, excreted from hepatocytes and connective tissue cells by means of exocytosis take an active part in collagen extracellular degradation in vivo; at initial stages of cirrhosis involution extracellular degradation of collagen in the liver occurs at the expense of lysosomal enzymes from hepatocytes and connective tissue cells. Subsequently, as cirrhosis regresses, the principal role in the lysis of collagen gradually passes to lysosomal enzymes of hepatocytes.

Acid Phosphatase↗
PubMed1986

[Acid phosphatase distribution in the liver in cirrhosis].

The distribution of acid phosphatase in liver cirrhosis, as well as in its reverse development, was investigated in mice using histochemistry and electron histochemistry methods. Histochemistry demonstrated a sharp activity increase of acid phosphatase (as compared with the same in the material of partial hepatectomy) in liver cells (especially hepatocytes) during liver cirrhosis regression 10 days after a partial hepatectomy. Electron histochemistry has shown the enzyme withdraw out of hepatocytes and connective tissue cells of fibrotic stratum in the extra-cell medium. The reaction product localized on the neighbouring collagen fibres giving evidence that during reverse development of liver cirrhosis the lisosomal enzyme release from specified cells by means of exocytosis and they are involved in the lysis of collagen.

Acid Phosphatase↗
PubMed1985

[Ultrastructural aspects of the reversible nature of sclerotic changes in the liver].

Experiments on mice have demonstrated ultrastructural changes in collagen and hepatocytes during reverse development of liver cirrhosis. Progressive lysis of collagenous fibers has been noted. Changes in hepatocytes point to a rise in the synthetic and endocytosis activity in these cells. It is suggested that exocellular lysis of collagen in the process under consideration is initiated by collagenase whereas subsequently it takes place under the action of lysosomal enzymes secreted by hepatocytes to the exocellular space.

Animals↗
PubMed1985

[Collagen resorption by macrophages and fibroblasts in liver cirrhosis].

Intracellular lysis of collagen by macrophages and fibroblasts in liver cirrhosis and during its reverse development has been shown in experiments on mice by electron microscopy and electron histochemistry. Based on the data obtained it is concluded that in the process under consideration, there occur phagocytosis and intracellular resorption of collagen by macrophages and fibroblasts and that intracellular collagen lysis in the cells in question occurs in the presence of active involvement in the process of lysosomal enzymes.

Absorption↗
PubMed1984

[Lysosome participation in collagen resorption by hepatocytes during regression of liver cirrhosis].

Electron microscopy and electron histochemistry employed in experiments on mice with liver cirrhosis regression have demonstrated the presence of vacuoles with collagen in the cytoplasm of hepatocytes as well as the presence in these vacuoles of a reaction product to acid phosphatase. Based on the data obtained it is concluded that during liver cirrhosis regression, there takes place an intracellular resorption of collagen by hepatocytes via phagocytosis with an active involvement in this process of lysosomal enzymes.

Absorption↗