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Biomedical subjects

L E Panin

Publications and source records attributed to L E Panin.

At least 19 recordsLinked to original sources
PubMed2006

Changes in the secondary structure of highly polymeric DNA and CC(GCC)n-type oligonucleotides under the action of steroid hormones and their complexes with apolipoprotein A I.

A small-angle X-ray scattering study showed that the action of tetrahydrocortisol (THC) in complex with apolipoprotein A I (ApoA-I) on DNA leads to local melting of DNA. The most probable site of interaction between this complex and DNA is the (GCC)n-type sequence. Oligonucleotides (duplexes) of this type have been synthesized. It was demonstrated that the interaction of this oligonucleotide with the THC-ApoA-I complex leads to dissociation into complementary oligonucleotides. The latter ones also interact with the THC-ApoA-I complex. The kinetics of this multistep process is presented. The mechanism of interaction between hormones or their ApoA-I complexes and duplex CC(GCC)5.GG(CGG)5Li2 was studied using IR spectroscopy. It was shown that the interaction with THC or the THC-ApoA-I complex leads to the formation of hydrogen bonds between the OH group of the hormone A-ring and the C=O group of cytosine or guanine. Interaction with cortisol or the cortisol-ApoA-I complex leads to the formation of a hydrogen bond with the NH group of cytosine; in addition, THC and cortisol form hydrogen bonds with the PO2 group of the duplex and with the OH group of the monosaccharide. The interaction of ApoA-I with the duplex is accompanied by the formation of hydrogen bonds between the protein NH2 group and the C=O group of cytosine and the P=O group. The order-to-order structural transition takes place in the duplex under the action of THC or cortisol, with THC causing a higher ordering as compared to cortisol. The order-to-disorder structural transition occurs in the duplex under the action of the THC-ApoA-I, cortisol-ApoA-I, or ApoA-I complexes. Shifting the pH of the medium from 7.2 to 6.0 also leads to an order-to-disorder-type structural transition.

Animals↗
PubMed2006

[Role of Mg2+-dependent alkaline endodnaase of blood serum in tumorigenesis in A/smail mice].

An enzymoassay of levels of Mg2+-dependent alkaline endoDNAase of protein spectrum of blood serum of noninbred albino mice by SDS-electrophoresis in 10% PAAG established a fairly high heterogeneity of the enzyme. The variety of alkaline endoDNAases must be due to the limited proteolysis of their high-molecular precursor by specific proteases as described in the literature. No alkaline endoDNAase activity was identified by analysis of 10-150 kDa protein spectrum in A/smail line mice without ascites hepatoma. It was detected (pH 8.3) in the 25-45 kDa range on day 10 after tumor transplantation. Considering the gravity of disease (pre-lethal stage), on day 10, it was suggested that the level be accounted for by decay of diseased cells. The lack or extremely low level of endoDNAase activity in original blood serum expressed a mechanism of enhancing sensitivity to tumor cell effects. In mice bearing ascites hepatoma, the enzyme levels (pH 8.3) were much higher on day 10. DNAase activity (pH 7.5) was not induced in response to the heterogenous DNA. Our data point to possible defects in the induction of Mg2+-dependent alkaline endoDNAases (pH 8.3) and DNAses (pH 7.5) as well as their role in raising sensitivity to transplantable ascites hepatoma.

Animals↗
PubMed2005

Apolipoprotein A-I possessing activity of defensin proteins modifies structure of plasma membranes.

We studied the in vitro effect of apolipoprotein A-I possessing activity of defensin proteins on the structure of plasma membranes in donor erythrocytes and lymphocytes. Incubation of erythrocyte membranes with apolipoprotein A-I was accompanied by significant changes in biophysical characteristics of a fluorescent probe pyrene in the hydrophobic membrane region and a decrease in Na+/K(+)-ATPase activity. Microviscosity of annular lipids in the plasma membrane of lymphocytes increased during incubation with apolipoprotein A-I. Our results suggest that membranotropic activity of apolipoprotein A-I is associated with the presence of amphipathic alpha-helix regions.

Apolipoprotein A-I↗
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↗
PubMed2004

[Penetration of lipoproteins and apolipoproteins of very low density into the myocardium and changes of its structure in rat heart perfusion].

The method of electron microscopy, involving extra-low density lipoproteins (ELDLP) marked by colloid gold as well as their protein components (i.e. apolipoproteins--apoELDLP), was made use of to show that they are captured by capillary endotheliocytes of the isolated perfusing rat heart. Receptor-mediated endocytosis is the main mechanism of penetration. Within 30 minutes, ELDLP interact with the capillary wall, pass through the endothelial barrier and, from the intersticium, they are captured by tissue microphages, which induces their activity. They have, on the whole, a positive effect on the intactness of muscle cells of the beating heart. During the same time span, apoELDLP remain in endotheliocytes, however, they exert a pronounced negative impact on the myocardium. The capillary endothelium, in whose cells the lysosomal apparatus activates itself and clasmatosis sets on, is affected morphologically most of all. The impairment of the capillary endothelium, development of the perivascular edema and a reduced coronary flow trigger a sequence of events leading to enhanced cytolytic processes in the myocardium due to an activated lysosomal apparatus of cells.

Animals↗
PubMed2003

Tetrahydrocortisol-apolipoprotein A-I complex specifically interacts with eukaryotic DNA and GCC elements of genes.

Tetrahydrocortisol stimulates DNA and protein biosynthesis in hepatocytes only when it enters the complex with apolipoprotein A-I. Tetrahydrocortisol-apolipoprotein A-I (THC-apoA-I) complex specifically interacts with eukaryotic DNA isolated from rat liver. In the process of interaction, rupture of hydrogen bonds between the pairs of nitrous bases occurs with the formation of single-stranded DNA structures. In such state DNA forms complexes with DNA-dependent RNA-polymerase. The most probable site of binding the tetrahydrocortisol-apolipoprotein A-I complex with DNA is the sequence of CC(GCC)(n) type entering the structure of many genes, among them the structure of human apolipoprotein A-I gene. Oligonucleotide of this type has been synthesized. Association constant (K(ass)) of it with tetrahydrocortisol-apolipoprotein A-I complex was shown to be 1.66 x 10(6)M(-1). Substitution of tetrahydrocortisol for cortisol in the complex results in a considerable decrease of K(ass). It was assumed that in the GC-pairs of the given sequence tetrahydrocortisol itself participates in the formation of hydrogen bonds with cytosine, favoring their rupture with complementary base-guanine.

Animals↗
PubMed2003

Fluorescent probing of lymphocyte and erythrocyte plasma membranes in persistence of tick-borne encephalitis virus: monitoring of structural changes.

The structure of lymphocyte and erythrocyte plasma membrane in patients with long persistence of tick-borne encephalitis virus was studied using fluorescent probes pyrene and 1-anilinonaphthalene-8-sulfonate. The authors analyze the clear-cut disorders in the membranes of both lymphocytes and erythrocytes in viral tick-borne-encephalitis from the viewpoint of generalized involvement of cell membranes in infectious process.

Adult↗
PubMed2003

[Distribution of the labeled lipoproteins in the myocardium during perfusion of the isolated rat heart and adrenaline administration].

The distribution of different classes of colloidal gold-labeled lipoproteins (LP) was studied at the ultrastructural level in rat myocardium using the isolated heart perfusion following the adrenaline stimulation. The distribution of label was examined in endotheliocytes, macrophages and in the interstitial space. The addition of adrenaline to Krebs solution during 30 min of heart perfusion in vitro was shown to increase the amount, but to decrease the velocity of penetration of labeled LP of very low and low density into the myocardium. The intensive utilization of lipid component from LP in the conditions of stimulation provides for the enhanced metabolic requirements of the cardiomyocytes and good preservation of their ultrastructure. It is possible that colloidal gold-associated protein component of LP is incorporated by the endothelium more slowly. The label penetrates into the interstitium and is accumulated in the activated macrophages. If high density LP are added together with adrenaline into the perfusion medium the label does not leave the capillary wall, while macrophages and cardiomyocytes acquire the ultrastructural features of high functional activity.

Animals↗
PubMed2003

[Role of innate macrophages in DNA and protein biosynthesis in cultured cells of murine (line A) ascitic hepatoma].

Joint effect of high-density lipoproteins (HDLP) and glucocorticoids presence is responsible for increased protein and DNA biosynthesis in the cells of the hepatic parenchyme. Hepatic innate macrophages devour HDLP and glucocorticoids and release the A-1 tetrahydrocorisol-apolipoprotein complex which in turn is channeled into interstitial spaces to be captured by hepatocytes, thus stimulating protein and DNA biosynthesis. This mechanism was observed in cultured cells of murine ascitic hepatoma; it was regulated by macrophages present in incubation medium. The rate of protein and DNA biosynthesis remained constant unless HDLP and glucocorticoids were present in the medium and in a macrophage-containing culture alone.

Animals↗
PubMed2002

Role of lipoproteins transporting lipophilic xenobiotics in the induction of microsomal monooxygenases.

We studied the effects of lipopolysaccharide on activity of liver microsomal enzymes against the background of xenobiotics treatment. Against the background of lipopolysaccharide stimulation of macrophages we observed in vivo activation of cytochromes P-450 1A subfamily in liver microsomes with Arochlor 1254, but not induction of cytochrome P-450 2B subfamily with phenobarbital.

Animals↗
PubMed2002

Interaction of human apolipoprotein A-I with rsCD4 receptor.

The interaction between recombinant soluble CD4 receptor (rsCD4) with human apolipoprotein A-I was studied by enzyme-linked immunosorbent assay. Our findings suggest that HIV-1 and human apolipoprotein A-I compete for the CD4 receptor and receptor for apoA-I.

Apolipoprotein A-I↗
PubMed2002

Effect of tetrahydrocortisol-apolipoprotein A-I complex on the secondary structure of eukaryotic DNA and its interaction with RNA-polymerase.

The in vitro effect of tetrahydrocortisol-apolipoprotein A-I complex on native adult rat liver DNA results in the formation of S1 nuclease sensitive fragments that are irregularly distributed throughout a genome. Low-angle X-ray scattering showed that after the interaction with the tetrahydrocortisol-apolipoprotein A-I complex, DNA can bind to RNA-polymerase with a high and dose-dependent cooperativity. This indicates that the effect of tetrahydrocortisol-apolipoprotein A-I complex on secondary eukaryotic DNA structure causes a local denaturation of the double helix, promoting high cooperativity of binding to RNA-polymerase. The reduced form of the hormone, tetrahydrocortisol, previously considered as an inactive metabolite, when complexed with apolipoprotein A-I, promotes a biological function similar to that of a transcription factor.

Animals↗
PubMed2002

[Penetration of lipoproteins through a capillary wall and their effects on the cardiomyocyte ultrastructure during in vitro heart perfusion].

The colloidal gold-labeled lipoprotein (LP) distribution in the myocardium after the 30 min perfusion of isolated working rat heart was studied by electron microscopy. LP of physiological concentrations are shown to be able to interact with the capillary wall and they can be incorporated by endotheliocytes. The velocity and transportation mechanisms of different classes of LP differ. Very low density LP are the most intensively taken up, low density LP enter into interstitium more rapidly than others, high density LP do not leave the capillary wall at all. The passages of labeled LP through endotheliocytes by the receptor-mediated as well as the non-receptor manners are revealed. The transportation through the widened intercellular junctions may be supposed for low density LP. For the fist time LP addendum into the perfusion medium was shown to provoke the activation of interstitial macrophages. During the perfusion duration they take inside and accumulate labeled very low density LP and low density LP in their lysosomes. The internalization may be performed by the specific endocytosis or by the simple phagocytosis. The qualitative and morphometrical analyses show that LP preserve the capillary and cardiomyocyte ultrastructure from perfusion injuries. One may suppose that there are interrelations between the capillary endothelium, the interstitial macrophages and the parenchymal cells in myocardium for realization of plasma LP effects.

Animals↗
PubMed2002

[Effect of combined glucocorticoids and low density lipoproteins on structural and functional changes in hepatocytes and Kupffer cells ].

The combined action of cortisol and low density lipoproteins (LDL) on the hepatic cell functional activity associated with protein biosynthesis was investigated by biochemical, radioisotope, and ultrastructural methods. The preferential uptake from blood serum of high and low density lipoproteins and glucocorticoids in vivo is enhanced, when residential macrophages are stimulated by prodigiozanum belonging to lipopolysaccharides (LPS). Liver macrophages actively take up colloidal gold (labeled LDL) by receptor-mediated endocytosis. The labels are followed in endosomes and lysosomes of Kupffer cells, and in Disse's space, though there are only single granules in hepatocytes. It is suspected that products of glucocorticoid chemical modification (tetrahydrosubstances) and LDL of limited proteolysis, while entering hepatocytes, may co-operatively activate their nucleolar DNA, that manifests in the increase in nucleolar dimensions and relative volume of granular component in them. In the cytoplasm, the density of ribosomes on the rough ER membranes significantly grows, the relative volume of the smooth ER and the number of primary lysosomes increase. In the co-culture of hepatocytes and Kupffer cells under the combined influence of cortisol, LDL and LPS, the protein biosynthesis considerably accelerates. One may suppose that LDL, on transporting steroid hormones and lipophilic xenobiotics into hepatic cells, may take part in the induction of lysosomal and monooxygenase oxidative system enzymes attributed to smooth ER.

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↗