Search PubMed⌕ Search

Biomedical subjects

S Ivanov

Publications and source records attributed to S Ivanov.

At least 181 records · Page 10Linked to original sources
PubMed1986

Galactosyltransferase: multiple forms in serum of normal and hepatoma Mc-29 bearing chickens and from liver and hepatoma microsomal and plasma membrane preparations.

The multiple forms of galactosyltransferase in chicken serum and in microsomal and plasma membrane preparations from liver and viral induced hepatoma Mc-29 have been studied by isoelectric focussing. An elevation of the hepatoma plasma membrane enzyme activity was described and in the pattern of the multiple forms of the enzyme two forms were found (pI-5.34 and 8.22) which were similar to those described in the serum of hepatoma bearing chickens (pI-5.36 and 8.24). A conclusion is drawn that these enzyme forms are apparently present to a greater extent in the hepatoma plasma membrane enriched fractions than in liver membranes and are probably shed into the serum of the tumor bearing animals.

Animals↗
PubMed1985

Studies on N-acetylneuraminic acid biosynthesis in chicken liver and hepatoma Mc-29 by using [14C]N-acetylmannosamine and [14C]glucosamine.

The biosynthesis of free N-acetylneuraminic (sialic) acid (N-acetylneuraminic + CMP-N-acetylneuraminic acid) in chicken liver and hepatoma Mc-29 by using [14C]N-acetylmannosamine and [14C]glucosamine was studied in vivo. The specific activity (SA) of hepatoma N-acetylneuraminic acid labelled with [14C]glucosamine is lower than that of liver, showing that the rate of conversion of UDP-N-acetylglucosamine to N-acetylneuraminic acid is reduced in tumor cells. The biosynthesis rate of sialic acid in hepatoma cells is higher when [14C]N-acetylmannosamine was applied. The UDP-N-acetylglucosamine-2'-epimerase activity was nearly 3-fold lower in hepatoma compared to that in liver. The time course of [14C]N-acetylmannosamine incorporation into free and protein bound sialic acid in hepatoma and liver was also showed. The SA of hepatoma protein bound sialic acid remained lower in all time points investigated. The results agree with the assumption that the metabolic pathways leading to sialic acid synthesis and to sialylation of tumor glycoconjugates are altered after malignant transformation.

Animals↗
PubMed1985

Glycosidases in normal and regenerating chicken liver, hepatoma Mc-29, Rous sarcoma, in turkey poult liver and hemocytoblastomes, provoked by the leukosis virus strain Mc-31.

Four glycosidases (beta-galactosidase, alpha-mannosidase, alpha-fucosidase and beta-N-acetylglucosaminidase) were studied in chicken normal and regenerating liver, in turkey poult liver and in virus induced avian tumors--chicken hepatoma (strain Mc-29), Rous sarcoma (strain Schmidt-Ruppin) and turkey poult hemocytoblastoma nodules (strain Mc-31). The multiple forms of beta-N-acetylglucosaminidase were assayed as well. A particular enzyme pattern was found in the tumor lines under investigation. A characteristic property of hepatoma cells was the elevation of beta-galactosidase activity and of the former enzyme and that of beta-N-acetylglucosaminidase for the hemocytoblastoma. In Rous sarcoma the glycosidase activities (except that of alpha-fucosidase) were much lower, compared to the other two solid tumors. All enzyme activities were compared with those in the normal liver of the corresponding avian species, and with the liver of tumor bearing fowls and with regenerating chicken liver. Unlike the rat liver in the avian normal and tumor tissues the percentual ratio between the multiple forms A and B of beta-N-acetylglucosaminidase was found to be 30:70%.

Acetylglucosaminidase↗