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Biomedical subjects

L E Panin

Publications and source records attributed to L E Panin.

At least 55 records · Page 3Linked to original sources
PubMed1995

[The role of the adenine nucleotide carrier in regulating energy and ion permeability of rat liver mitochondria upon cold exposure].

The energy state of rat liver mitochondria on day 10 of cold acclimation, when the body temperature decreases significantly concomitantly with an increase in the content of long-chain acyl-CoAs in the liver, has been studied. State 4 and uncoupling respiration rates increase in parallel; however, the integral potentials of the adenine nucleotide system in the liver diminish. In the presence of oligomycin, ADP (20 and 50 microM) decreases the II(+)-permeability and increases the Ca(2+)-capacity of mitochondria in both control and, in a lesser degree, cold-exposed rats. At 90 microM ADP has the same effect on mitochondria of both groups of rats. Carboxyatractylate abolishes the ADP effect on the mitochondria. In EGTA-containing media carboxyatractylate decreases the respiration rate in oligomycin-treated mitochondria. Palmitoyl-CoA increases the II(+)-permeability of the mitochondrial membrane and decreases the Ca(2+)-capacity of mitochondria. ADP abolished the competitive effects of this long-chain acyl-CoA. Possible involvement of the ATP/ADP antiporter in the thermoregulatory response of liver mitochondria in cold-acclimated rats and the role of fatty acids and long-chain acyl-CoAs in this process are discussed.

Acyl Coenzyme A↗
PubMed1995

[Energy status of rat liver during the dynamics of cold adaptation].

The energy state of rat liver at various times of cold acclimation has been studied. On day 10 of cold exposure, the energy state of the liver is characterized by a low level of ATP and the adenine nucleotide pool as well as by low values of the phosphorylation potential and the "energy charge". The respiratory control is decreased, while the low permeability of the inner mitochondrial membrane is increased. It is supposed that on days 10-15 after cold exposure the liver becomes actively involved in thermal stabilization. Cold acclimation on days 35-42 leads to an increase in State 3 respiration rate, respiratory control and energization of liver mitochondria. This allows to maintain the ATP level and the total adenine nucleotide pool in liver tissues at the control level. However, this does not seem to compensate completely for the energy expenditure because the phosphorylation potential and the "energy charge" of the liver are thereby decreased.

Adaptation, Physiological↗
PubMed1995

[The role of nonparenchymal liver cells in activating protein synthesis in hepatocytes upon stimulating the mononuclear phagocyte system with lipopolysaccharide].

It has been found that the rate of hepatocyte protein synthesis depends on the functional state of nonparenchymal liver cells (NPC), of Kupffer cells, in particular. When Kupffer cells were stimulated by intravenously injected lipopolysaccharide (LPS), zymosan or dextran sulfate, the rate of [14C]leucine incorporation into hepatic proteins increased 1.5-2-fold. Similar effects were observed in hepatocytes cocultured with NPC isolated from LPS-stimulated rats as well as in hepatocytes cultured in a conditioned medium from NPC treated with LPS, high density lipoproteins (HDL) and hydrocortisone. It is proposed that apoproteins of HDL resecreted by Kupffer cells may participate in the regulation of hepatocyte gene expression during stimulation of resident macrophages.

Animals↗
PubMed1995

[Several problems of nutrition and health of children in the Russian North].

The article includes the developed analysis of the references and the results of private researches about the problems of nourishment and health of the boarding-school's children from the Russian North. It is pointed out, that in the Northern district the children's nourishment must have a protein-lipid level. It is so that a ration carbo-hydrate level is not able for the child organism to adopt in the strong climatic conditions and has a negative effect for their physical state and health too. The retrospective analysis of nourishment is worked out according to boarding-school's children of Tajmir for the last 20 years.

Child↗
PubMed1994

[Role of apo B-containing lipoproteins in the development of exertional diabetes in humans under Arctic and Antarctic conditions].

Under extreme conditions of the Arctic and Antarctic, man develops exertional diabetes, which is characterized by (1) decreases in blood insulin levels and in responses of the insular apparatus to glucose load; (2) a reduction in blood sugar; (3) a drop in glucose uptake; (4) lowering of the renal barrier for blood sugar and other low-molecular weight compounds; (5) appearance of urinary sugar and an increase in its nocturnal resting concentration. Exertional diabetes lies in the basis of switching energy metabolism from the carbohydrate to lipid types at high latitudes. The mechanism of this phenomenon is associated with the contra-insular effect of LDL and VLDL. There is a common epitope in the beta-chain of insulin and LDL and VLDL apoprotein B. The existence of the common epitope leads to competition of insulin and apoprotein B for an insulin receptor and reduces tissue glucose uptake.

Adult↗
PubMed1994

[The diagnostic and prognostic assessment of the changes in lysosomal enzymatic activity in the blood of patients with acute myocardial infarct and unstable stenocardia].

Serum activity of five lysosomal marker enzymes was measured in patients with acute myocardial infarction (AMI) and unstable angina pectoris (UAP) with consideration of the disease severity. A significant increase of enzyme activity was found both in patients with UAP and AMI on the first day of hospitalization. The enzymes activity was higher in patients with more severe form of AMI. Lysosomal enzyme activity was closely related to severity of the disease: clinical improvement occurred in patients with decreased activity (on day 7-10), while in aggravation of the disease lysosomal hyperenzymemia stayed high up to the end of the observation period (on day 30). The above findings demonstrate feasibility of using lysosomal enzymes test both for differentiation between AMI and UAP and for predicting the disease recurrences.

Adult↗
PubMed1994

[The role of hepatocytes, Kupffer, and endothelial cells of the liver in blood lipoprotein metabolism].

The rates of blood lipoprotein adsorption by hepatocytes and nonparenchymal cells (NPC) of rat liver have been quantitatively characterized. It was found that the lipoprotein-adsorbing capacity of NPC is higher than that of hepatocytes: 5.6 times for very low density lipoproteins (VLDL), 4.3 times for low density lipoproteins (LDL) and 14.4 times for high density lipoproteins. Stimulation of the mononuclear phagocyte system by a lipopolysaccharide from Serratia marcescens resulted in a significant reduction of blood serum levels of HDL3, LDL and glucocorticoids. Under these conditions the binding of [125I]HDL to hepatocytes increased, while that to Kupffer's cells decreased considerably. In response to stimulation of liver resident macrophages (Kupffer's cells) the rate of protein biosynthesis in hepatocytes increased together with an increase in the rate of [14C]leucine incorporation into the protein component of the blood serum lipoproteins. Enhanced gene expression in the hepatocytes seems to be associated with the cooperative action of HDL and glucocorticoids. Adsorption of lipoproteins by activated Kupffer's cells is due to the receptor-mediated endocytosis, resulting in a decrease of the binding capacity of these cells for HDL and LDL.

Animals↗
PubMed1993

[The effect of stimulation of the mononuclear phagocyte system on the binding of high- and low-density lipoproteins by the hepatocytes, Kupffer cells and liver endotheliocytes of rats].

The role of the mononuclear phagocyte system (MPS) in the regulation of low- (LDL) and high-density lipoprotein (HDL) receptor activity in different rat liver cells was investigated. MPS was activated by intravenous administration of bacterial lipopolysaccharide (LPS) from Serratia marcescens. Liver cells were isolated by in vitro perfusion of the liver with a collagenase solution. Separation of Kupffer and endothelial cells was performed by the method of centrifugal elutriation. In control rats, the hepatocytes bound 1.6 times more 125I-HDL and 2.5 times more 125I-LDL per cell than Kupffer cells. Treatment of rats with LPS resulted in a 4.5-fold decrease in the 125I-HDL binding to Kupffer cells. In contrast, the hepatocytes from LPS-treated rat bound 2 times more 125I-HDL than that from untreated rats. The binding of 125I-LDL and 125I-HDL to endothelial cells and 125I-LDL to hepatocytes were not affected by LPS treatment. These results suggest that the MPS (especially Kupffer cells) plays an important role in the regulation of HDL receptor activity in hepatocytes.

Animals↗
PubMed1992

[The receptor binding of 3H-corticosterone by rat hepatocytes].

The binding of 3H-corticosterone was studied on rat hepatocytes both in presence of unlabeled corticosterone, obsidan and their absence at 0 degrees-4 degrees C. The analysis of binding by the method of Scatchard showed that there are two types of specific binding sites for 3H-corticosterone. Possible existence of proper glucocorticoid receptors (Ka = 4 x 10(9)M-1, n = 0.52 x 10(-14) mol/mg prot.) has been shown, as well as possibility of 3H-corticosterone interaction with beta-adrenoreceptors (Ka = 1.2 x 10(9)M-1, n = 0.9 x 10(-14) mol/mg prot.) have been demonstrated on hepatocytes.

Animals↗
PubMed1992

[Detection of apoprotein A-1 immunoreactivity in chromatin of rat hepatocytes].

The binding of 125I-labeled lipoproteins to subcellular structures of rat hepatocytes was studied. The protein component of HDL, LDL, and VLDL was found in large and small membranes, nuclei, mitochondria, lysosomes, microsomes, and cell cytosol. The presence in liver nuclear chromatin of proteins immunochemically related to apoA-1 was demonstrated by solid phase immunoenzymatic analysis, dot immunoanalysis, and immunoelectroblotting. The apoprotein A-1 immunoreactivity was detected in transcriptionally inactive total chromatin, transcriptionally active chromatin, and nuclear matrix. The specific apoA-1 immunoreactivity of transcriptionally active chromatin and nuclear matrix was two times as low as that of total and transcriptionally inactive chromatin. Immunoelectroblotting revealed two proteins possessing an apoA-1 immunoreactivity (M(r) 28 and 14 kDa). The 28 kDa protein was found in transcriptionally active chromatin and nuclear matrix, while the 14 kDa one--only in transcriptionally inactive chromatin. the roles of apoproteins in lipid transport to nuclei and the maintenance of chromatin in a transcriptionally active state are discussed.

Animals↗
PubMed1992

[Quantitative characteristics of interactions of blood lipoproteins and steroid hormones].

Human and serum lipoproteins interaction with steroid hormones (corticosterone and hydrocortisone) were studied. Methods of fluorescence quenching titration and equilibrium dialysis were used for quantitative evaluation of VLDL, LDL and HDL glucocorticoids binding ability. Association constants were found to be 0.6-2.0 x 10 M for corticosterone and 4.0-8.0 x 10 M for hydrocortisone. The number of binding sites ranged from 3 to 300 for different classes of lipoproteins. Our data suggest high specificity of serum lipoproteins binding with corticosterone and hydrocortisone.

Animals↗
PubMed1991

[The intracellular distribution of labelled lipoproteins in the tissues of rats under physical loading].

A study was made of the influence of a 3 hour physical loading on the intracellular distribution of 125I-labeled very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL) in the rat tissues after intravenous injection. The uptake of VLDL by liver was decreased, that of LDL was not altered and that uptake of HDL was increased, Redistribution of labeled lipoproteins between the subcellular structures was found. Accumulation of labeled VLDL in cytosol, microsome and large membranes was observed in muscles. The radioactivity level of VLDL was decreased in lysosomes, whereas the level of HDL was increased, Physical loading increased the uptake of HDL in adrenal glands. Accumulation of radioactivity was found in cytosol and small membranes. The data confirm the important role of lipoproteins of cellular metabolism regulation.

Adrenal Glands↗