Biomedical subjects

L M Polyakov

Publications and source records attributed to L M Polyakov.

6 recordsLinked to original sources

PubMed2004

Effect of polysaccharides and human plasma lipoproteins on the secretion of cystatin C by peritoneal macrophages from normal and tumor bearing mice.

Intact peritoneal macrophages in vitro secreted the cysteine proteinase inhibitor cystatin C. Polysaccharides stimulated cystatin C secretion: lipopolysaccharide < carboxymethylated beta-D-glucan < sulfoethylated beta-D-glucan. Human plasma low-density- (LDL) and high-density lipoproteins (HDL) are still more potent inducers of cystatin C secretion by macrophages. Peritoneal macrophages from mice with experimental HA-1 hepatoma compared to those from intact mice secreted more cystatin C with maximum polysaccharide-stimulated secretion after 30 min of incubation. LDL and HDL induced cystatin C secretion by tumor macrophages also.

Animals↗

PubMed2001

Involvement of adenine nucleotide carrier in the mechanism of the apolipoprotein C induced decrease of membrane potential in rat liver mitochondria.

Apolipoprotein C (apo C) was shown to decrease the Ca2+ capacity and membrane potential of mitochondria isolated from rat liver. The specific ligands of adenine nucleotide carrier, ADP and carboxyatractyloside (CAT), inhibited the effect of apo C on the mitochondrial membrane potential. The effect of ADP and CAT was revealed in the absence of Ca2+. We conclude that in the presence of apo C, adenine nucleosides carrier transforms into a pore, and this causes the decrease in the membrane potential of the mitochondria. ADP and CAT support the primary conformation of the carrier and therefore inhibit the effect of apolipoprotein C.

Adenosine Diphosphate↗

PubMed2000

Effects of apolipoproteins C on oxidative phosphorylation in rat liver mitochondria.

It is shown that apoC-III, but not other apoC proteins, components of very low density lipoproteins (apoC-I, apoC-II, apoC-III), reduced the rate of mitochondrial respiration in various metabolic states. This effect depended on the dose of apoprotein, type of oxidized substrate, and the presence of Ca ions in the incubation medium. ApoC-III completely blocked oxidative phosphorylation during oxidation of palmitoyl carnitine by mitochondria, while the respiration rate in metabolic state 4 remained unchanged.

Animals↗

PubMed2000

Detection of apolipoprotein A-I, B, and E immunoreactivity in the nuclei of various rat tissue cells.

Proteins with apolipoprotein A-I immunoreactivity were detected in the fraction of non-histone acidic proteins isolated from nuclei of various rat tissue cells. These proteins were detected in the brain, liver, kidney, lung, heart, skeletal muscle, testis, spleen, and bone marrow. In the same fraction from liver nuclei, proteins with apoB and apoE immunoreactivity were also detected. The composition of these proteins was studied by immunoblotting. ApoA-I immunoreactivity in the liver nuclei is due to two proteins. One 28-kD protein corresponds to the mature form of the plasma pool of apoA-I and another 14-kD protein is the product of limited proteolysis of apoA-I. The highest content of apoA-I immunoreactivity was detected in transcriptionally active chromatin and nuclear matrix. ApoB immunoreactivity is due to six proteins with molecular weights from 15 to 100 kD. ApoE immunoreactivity is due to a single protein corresponding to the 35-kD form of plasma apoE. Proteins with apoA-I, apoB, and apoE immunoreactivity may be involved in the regulation of transcriptional activity of chromatin.

Animals↗

PubMed1998

Distribution of tocopherol and apolipoprotein A-I immunoreactivity in rat liver chromatin.

[125I]Labelled lipoproteins (HDL, LDL, and VLDL) are actively taken up by the rat liver. The uptake rate in nonparenchymal liver cells was significantly higher than that in hepatocytes. Analysis of the distribution of the labelled lipoproteins in liver subcellular structures showed the presence of these compounds in the nuclei. The presence of apoA-I, apoB and apoE immunoreactivity in liver cell nuclei was demonstrated by immunochemical methods (ELISA and dot immunoassay). The nuclear matrix and transcriptionally active chromatin displayed the highest apoA-I levels, which considerably exceeded those in the total and transcriptionally inactive chromatins. A similar distribution pattern was observed for alpha-tocopherol. It is concluded that blood serum lipoproteins, primarily HDL, may transport tocopherol and other lipids into cell nuclei.

Animals↗

PubMedDate not supplied

Binding and transport of benzo[a]pyrene by blood plasma lipoproteins: the possible role of apolipoprotein B in this process.

The role of plasma lipoproteins as carriers in the transport of benzo[a]pyrene was assessed in in vitro and in vivo studies. Addition of [3H]benzo[a]pyrene to rat plasma resulted in binding of the xenobiotic to lipoproteins. Studies of labeled benzo[a]pyrene distribution in rat blood plasma by the method of ultracentrifugation have given the following results: high-density lipoproteins, 40%; low-density lipoproteins, 14%; very-low-density lipoproteins, 23%; other plasma proteins, 23%. Complexes of benzo[a]pyrene-lipoproteins were isolated by gel filtration with Sephadex G-25 and used for intravenous injection in rats. Biodistribution studies have shown different localization of benzo[a]pyrene in rat organs and tissues depending on lipoprotein classes. A high amount or radioactivity was bound by the liver and adrenals when all classes of lipoproteins were used, but especially with high-density lipoproteins. High levels of benzo[a]pyrene were measured in the kidneys. Equilibrium dissociation constants for complexes of benzo[a]pyrene with high-density lipoproteins and low-density lipoproteins were obtained (Kd 4.1 x 10(-5) and 1.5 x 10(-5) M, respectively). Binding and distribution of the protein component of lipoproteins were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. More than 80% of the radioactivity recovered from the gel was localized in the area of apolipoprotein B. After isolation and purification of apolipoprotein B, the equilibrium dissociation constant for complexes of benzo[a]pyrene with apolipoprotein B was obtained, and its value indicated that apolipoprotein B might be the main protein carrier for benzo[a]pyrene.

Animals↗