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Biomedical subjects

L E Panin

Publications and source records attributed to L E Panin.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Determination of apoprotein B using the method of solid-phase immunoenzyme analysis].

Indirect solid-phase enzyme immunoassay was used to measure apoB in human blood serum. ApoB obtained by traditional gel filtration in sepharose 4B and high-performance liquid chromatography was used as an antigen. Anti-apoB antibodies were immunochemically identified. Working regimens for the components and conjugates employed were selected. ApoB level in human blood serum, determined by this method, has made up 0.83 +/- 0.1 g/l in men and 0.88 +/- 0.1 g/l in women.

Apolipoproteins B↗
PubMed1991

[Effects of tocopherol on functional reserves of phagocytes].

The addition of alpha-tocopherol into rats died (4 mg a day during 7 days) brings a twofold increase in tocopherol content in blood plasma and 1,3 fold increase in peritoneal macrophages. Viscosity of membrane lipids of macrophages was decreased. Control and experimental macrophages had identical activity of oxygen-dependent processes and ability for cholesterol esterification.

Animals↗
PubMed1991

[Characteristics of binding and transport of benzo(a)pyrene by blood serum lipoproteins].

Binding and distribution of 3H-benzo[a]pyrene in lipoprotein fraction of rat blood serum were studied. The binding was enhanced in the row: LDL, VLDL, HDL, Kd lipoprotein-benzo[a]pyrene complexes had been calculated by means of tryptophan fluorescence quenching. It was found, that Kd value benzo[a]pyrene complexes with VLD was 1.5 x 10(-6) M, with LDL -6.6 x 10(-7) M and with HDL -4.2 x 10(-6) M. Radiolabeled benzo[a]pyrene uptake by rat organs and tissues was investigated after i.v. injection of benzo[a]pyrene-complexes with LP of different classes. High uptake activity was revealed for liver, adrenals and kidneys, whereas heart, spleen, thymus were characterized by low 3H-benzo[a]pyrene accumulation. Radioactivity distribution pattern was depended on the class of LP used for complexation. Ours data permit to evaluate the participation of lipoproteins in transport and metabolic pathways of xenobiotics in organism.

Animals↗
PubMed1990

[Solid-phase immunoenzyme analysis of apoprotein A-1].

The authors have optimized indirect solid-phase enzyme immunoassay for measuring human blood serum apoA-1. Immunochemical identification of the obtained apoA-1 and specific antibodies has been carried out, working regimens for the components and conjugates employed have been selected. Relationship between the method of preliminary treatment of the serum and the completeness of detected apoA-1 antigenic determinants is demonstrated. Normal blood serum apoA-1 level is 1.06 +/- 0.1 g/l in females and 1.05 +/- 0.1 g/l in male subjects.

Adult↗
PubMed1990

[Changes in the rate of protein synthesis in parenchymatous liver cells during stimulation of the mononuclear phagocyte system].

In vivo stimulation of mononuclear phagocyte system (MPS) by zymosan, dextrane sulfate, and prodigiosan caused almost a two-fold increase in hepatic protein synthesis. The rate of 14C-leucine incorporation increased both into total and soluble proteins. To define the cellular locus of these changes, preparations of hepatic parenchymal and nonparenchymal cells were obtained from the control and LPS-stimulated rats. The results indicate that the treatment of rats with prodigiosan stimulate protein synthesis in hepatocytes. No effect on protein synthesis of non-parenchymal cells was observed. Stimulation of MPS also caused a significant increase in 14C-leucine incorporation into serum lipoproteins. The results suggest that MPS may be involved in regulation of protein synthesis in hepatic parenchymal cells.

Animals↗
PubMed1989

[Effect of prodigiozan on the glucocorticoid and insulin ratio in the blood serum of white rats].

Significant hypertrophy of the adrenal glands was observed in Wistar rats the day after a single prodigiozan administration. This did not change the level of glucocorticoids in blood serum, but increased the concentration in insulin. Analysis of steroidogenesis in the adrenal glands indicated significant increase in steroid's production in the experimental group of rats as compared to the control. An increase of glucoso-6-phosphate dehydrogenase and hexokinase activity in adrenal tissue was also observed. The results suggest that stimulation of corticosteroid's secretion was accompanied by an increase in their reception to tissues which caused an increase of nonspecific resistance of the organism.

11-Hydroxycorticosteroids↗
PubMed1987

[Isolation of periportal and centrolobular hepatocytes by isopycnic centrifugation].

Suspensions of rat hepatocytes were separated by Ficoll discontinuous density gradient into four fractions. About 85% of the total quantity of cells sedimented within the range from 1.044 to 1.126 g/ml. The activity of key enzymes of glycolysis and gluconeogenesis were measured to determine the acinar origin of hepatocyte subpopulations. The activity of the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase, in hepatocytes with the density of 1.044 g/ml was twice as high as in hepatocytes with the density of 1.073 g/ml. In contrast, glycolytic enzyme, hexokinase, was 3 times more active in heavy than in light cells. The results indicate that light and heavy cells correspond to periportal and centrilobular hepatocytes, respectively.

Animals↗
PubMed1986

[Induction of cytochrome P-450 and b5 in hepatocyte subpopulations with phenobarbital].

Hepatocytes isolated from intact and phenobarbital-treated rats were separated by Ficoll discontinuous density gradient into five subpopulations. About 85% of the total cell number sedimented within the range of 1.044 to 1.126 g X cm-3. In intact rats, heavy hepatocytes contained about twice as much cytochrome P-450 and about 3 times as much cytochrome b5 as light cell population. Phenobarbital induced cytochrome P-450 in all subpopulations, with a more pronounced increase observed in light hepatocytes. On the contrary, maximum induction of cytochrome b5 was noted in heavy hepatocytes. The results demonstrate the absence of uniform distribution of cytochrome P-450 and b5 in hepatocyte subpopulations. The highest concentrations of both cytochromes are observed in heavy (centrolobular) hepatocytes.

Animals↗
PubMed1982

[Role of blood lipoproteins in adaptive reorganization of the rat liver mitochondria].

It was shown in experiments in vitro that high density lipids (HDL), very low density lipids (VLDL) and cAMP taken separately did not affect the kinetics of mitochondrial swelling in the liver of control and 72-hr-fasting rats. ApoHDL and particularly ApoVLDL obtained by delipidation of appropriate lipoproteins had pronounced capacities to stimulate the process of swelling. Mitochondrial swelling increased to an ever greater degree under the action of cAMP coupled with apoproteins. The maximum stimulation of the swelling was attained as a result of administering apoVLDL in conjunction with cAMP. The effects of enhanced swelling were the most remarkable in experiments with mitochondria from the control animals.

Adaptation, Physiological↗
PubMed1982

[Role of the lysosomes in altering glucose-6-phosphate dehydrogenase activity in the rat liver during intensive physical loading].

Experiments on rats have shown that heavy exercise induces the synthesis in the liver of the key enzyme of the pentosophosphate pathway, glucose-6-phosphate dehydrogenase. The maximum activity is reached 6 and 16 hours after the exercise. Initiation of the protein synthesis is related to activation of hepatocyte lysosomes and their translocation to the nucleus. Administration to the rats of the blockers of lysosomal translocation or an inhibitor of proteolytic activity one hour before swimming completely removes the inducing effect of lysosomes.

Animals↗
PubMed1981

[Effect of cAMP on hexokinase and glucose-6-phosphate dehydrogenase isoenzymes in different white rat tissues].

Preincubation of liver and skeletal muscle cytosol obtained from Wistar rats in the presence of cAMP, ATP and MgCl2 inhibited hexokinase. The decrease in the total enzymatic activity was a consequence of inhibition of types 2 and 3 hexokinase. The activity of type 1 hexokinase was unchanged. Under the similar conditions there was a lowering of the total activity of glucose-6-phosphate dehydrogenase which arose from inhibition of types 1 and 2 of the enzyme. The activity of other glucose-6-phosphate dehydrogenase isozymes remained unchanged. Preincubation of adrenal supernatant with cAMP, ATP and MgCl2 did not alter the activity of both enzymes. This is likely to be due to the absence of the respective cAMP-dependent proteinkinases and to the features of the isozyme spectrum. The results obtained indicate that hexokinase and glucose-6-phosphate dehydrogenase can be attributed to the group of enzymes that are regulated by the "phosphorylation-dephosphorylation" mechanism.

Adenosine Triphosphate↗
PubMed1981

[Effect of cAMP of glycolysis and glycogenolysis in the liver and adrenals of white rats].

The rates of glycolysis and glycogenolysis an the rate of lactate formation from glucoso-6-phosphate (G-6-Ph) in the liver were reduced during stress (starvation). On the contrary, these activities in the adrenals were increased. The rates of lactate formation from fructose diphosphate remained unchanged in both organs. The results obtained attest to the inhibition in the liver and activation in the adrenals of phosphorylase, hexokinase and phosphofructokinase. The degree of hexokinase inhibition in the liver depended on the presence of cAMP, ATP and MgCl2 in the incubation medium and was a consequence of enzymatic phosphorylation. Unlike 2', 3'-AMP, the inhibitory effect of CAMP was highly specific. The protein inhibitor of protein kinase completely reversed the inhibitory effect of cAMP on hexokinase. In the adrenals, cAMP slightly increased the rates of glycolysis and lactate formation from G-6-Ph because of allosteric effects of cAMP. The activation rather than inhibition of glycolysis in the adrenals during stress is probably caused by the absence in this tissue of cAMP-dependent protein kinase which phosphorylates hexokinase.

Adrenal Glands↗
PubMed1981

[Effect of cortisol, adrenaline and ACTH on the absorption and intracellular distribution of protein-labelled lipoproteins by rat liver and adrenal tissues].

One hour incubation of slices prepared from rat liver or adrenal glands with 125I labeled lipoproteins of different classes resulted in label binding and its penetration into the tissue cells. The greatest amounts of labeling were found in fractions of mitochondria, lysosomes, microsomes and the final supernatant. In relation to the weight unit, slices from adrenal glands consumed several times as much label as did liver slices. Epinephrine increased the amount of the label bound to the low density lipoproteins by several times in the fractions of large cell membranes, and decreased the 125I level in mitochondria. Cortizole increased the incorporation of the protein labeled lipoproteins very low density into the liver mitochondria. ACTH did not influence the incorporation or cellular distribution of the label in adrenal glands.

Absorption↗
PubMed1981

[Functional and ultrastructural lysosome changes in surviving rat liver sections as affected by blood serum lipoproteins].

Using surviving rat liver slices, the influence of blood serum lipoproteins on cellular lysosomes was studied. Lipoproteins were isolated by the preparative isopicnic ultracentrifugation method. Apoproteins were separated by means of delipidation of suitable lipoprotein fractions. After preincubation of liver slices in media with high density lipoproteins (HDLP), low and very low density lipoproteins (LDDLP, VLDLP), apo-HDLP and apo-VLDLP, the rise of free acid hydrolase activities was seen. The stability of lysosomes in hypotonic solutions turned out to be low, and the tendency to lysosomal aggregation increased. Typical peribiliary localization of lysosomes in the cell remained unchanged. Following preincubation of liver slices with hydrocortisone, adrenalin and VLDLP or LDLP, the rise of free lysosomal enzyme activity, greater aggregation and lysosome polymorphism and their less osmotic resistance took place. After liver slice preincubation with hormones and HDLP, besides all of these changes, the lysosomal translocation to the nuclei was seen. When apoproteins, separately or together with hormones, were added, the same type of alteration of lysosomal membranes occurred. Our results suggest an importance of lipo (apo) proteins in the control of structure and functions of cellular lysosomal apparatus.

Animals↗
PubMed1980

Lysosomal enzyme activity in hepatocytes and Kupffer cells from intact and partially hepatectomized rats.

Using hepatectomized rats it was shown that immediately after partial liver removal (PLR) the Kupffer macrophages were accumulated in liver remnant. At the maximal mitotic activity (36 hours following PLR) the relative amount of Kupffer cells keeps low, but 72 hours later turns out to be higher again. The periodic changes of the Kupffer cell amount in hepatectomized rats are accompanied by remarkable increase (1.5-3 fold) of free and total lysosomal enzyme activity (acid DNA-ase, acid RNA-ase, cathepsin D). The activation of the Kupffer macrophage lysosomes goes ahead of labilization of hepatocyte lysosomal membranes. The blockade of mononuclear phagocyte system by means of carbonate iron overloading in the early prereplicative period leads to an as long as 10-12 hours retardation of hepatocyte proliferation. The role of Kupffer macrophages in reparative liver regeneration is discussed.

Animals↗