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Biomedical subjects

L F Panchenko

Publications and source records attributed to L F Panchenko.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

[Lipid peroxidation, peroxyl radical-scavenging system of plasma and liver and heart pathology in adolescence heroin users].

Chronic opiate intoxication has been shown to cause various pathologic changes in the liver almost in 100% of cases. Earlier it has been demonstrated that acute or chronic morphine intoxication evokes activation of lipid peroxidation in the liver, heart, and brain cells. The aim of the present work was to assess parameters reflecting cytolysis in the liver and heart, and the plasma content of factors contributing to the peroxyl radical-scavenging system of the blood of teenagers using heroin. Blood samples were obtained from 20 male patients from 14 to 16 years old, with a mean duration of regular heroin use of 1.7 years. The control group included 13 healthy teenagers which denied the previous drug use. Mean plasma ALT and myocardial isoform of LDH activities were significantly higher (1.7- and 1.4-times respectively) in the heroin users than in the control group. The mean plasma level of lipid peroxides in the heroin users is increased by 20% compared to the control individuals. In teenagers using heroin a high level of correlation was observed between the plasma content of lipid peroxides and myocardial LDH activity (r = 0.76; P < 0.01). The effect of heroin use on the content of the plasma peroxyl radical-scavenging factors--vitamin E, ascorbic acid, and protein SH-groups--was not found. It has been concluded that heart injury during heroin use in teenagers may be associated with activation of lipid peroxidation reactions in the myocardium.

Adolescent↗
PubMedDate not supplied

[Nature of the effect "rapid oxygen consumption" during the introduction of tissue homogenate or a mitochondrial suspension into the polarographic cell].

After introducing rat brain homogenate or mitochondria into polarographic cell without adding the substrate a quick shift of recording pen from the point of initial concentration of oxygen towards zero is observed. According to Kotova and coworkers (Biochemia, 38, 287, 1973) this shift is accompanied by a decrease of oxygen concentration (less than oxygen rapid consumption greater than). We established that the size of this shift was not proportional to the quantity of homogenate. Boiled homogenate of the rat brain, liver DNA solution, starch gel and casein glue caused less than oxygen rapid consumption greater than. It was proposed to locate the point of the initial oxygen concentration on the polragoramme in the position of the recording pen after the introduction of homogenate into the polragoraphic cell.

Animals↗
PubMedDate not supplied

[Respiratory activity of Acholeplasma laidlawii cells and its role in the active transport of carbohydrates].

The respiratory activity of the Acholeplasma laidlawii cells was studied in order to elucidate a possible mechanism of coupling of transport with energy. The respiration of the cells is stimulated by ethanol, glucose, NADH, lactate, and pyruvate. The substrates of the Krebs cycle have no effect on the respiration. The respiratory activity, stimulated by ethanol and glucose, is inhibited by the inhibitors of the respiratory chain, SH reagents, and the inhibitors of glycolysis. The results of experiments with inhibitors suggest that the respiratory chain in the A. laidlawii cells is reduced and terminated by flavoprotein. This is confirmed by the results of spectroscopic analysis of cytochromes. Respiration coupled with phosphorylation did not play any important role in the active transport of carbohydrates. Probably, the energy, necessary for the transport of carbohydrates, is supplied by the substrate phosphorylation. This explains the activation of respiration by glucose, which is so sensitive to arsenate. The respiration of the A. laidlawii cells is not stimulated by some carbohydrates (fructose, 3-O-methyl-D-glucose).

Acholeplasma laidlawii↗
PubMedDate not supplied

[Regulation of opioid receptors by thyroliberin analogues].

The ability of thyroliberin (TRH) to interact with opioid receptors (OR) was studied using radioligand analysis. TRH did not influence specific binding of [3H]-naloxone, but increased affinity of high affinity binding sites for the ligand in a dose-dependent manner. TRH also decreased affinity of low- affinity binding sites. Kinetic analysis of low-affinity binding sites suggests the existence of at least two subpopulations of OR, which differed in their affinity to naloxone and mode of interaction with TRH. TRH acted as non-competitive and competitive inhibitor of receptor binding sites with the lowest and moderate affinity, respectively. The allosteric pattern of TRH influence on OR with high and the lowest affinity to naloxone was suggested. TRH analogues were estimated for their ability to change in OR binding characteristics. The level of [3H]-DADL specific binding was not influenced by the peptides tested but the affinity was changed. Blind control experiment showed the ability of the TRH relative substances to increase in affinity of d-receptors could be ranked in the row: dihydroorotyl-hystidyl-prolinamide > TRH > methionyl-asparagyl-phenylalaninamide. This is consistent with ability of these compounds to influence the dopaminergic events.

Animals↗
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[The withdrawal syndrome and lipid peroxidation during the chronic administration of narcotic analgesics to rats].

Diverse behavioral disorders and the intensity of lipid peroxidation (LPO) of biological membranes were estimated in different rat tissues after the 7-day administration and subsequent withdrawal of morphine or promedol. 24 hours after the withdrawal of the analgetics the demonstrated a high initial level of motor activity in the open field. Naloxone, an antagonist of opiate receptors, potentiated motor activity and the intensity of withdrawal syndrome (by 160%) in rats with morphine rather than promedol dependence. The behavioral disorders in dependent animals were accompanied by LPO activation in liver and brain membranes.

Analgesics, Opioid↗
PubMedDate not supplied

[Status of carbohydrate metabolism in the rat brain during alcohol withdrawal syndrome].

Periodically repeating alterations of carbohydrate metabolism were found in rat brain tissue under conditions of experimental alcohol withdrawal syndrome. Along with the maximal external manifestations of the withdrawal, a significantly higher glucose levels in all brain formations were observed, which was decreased within 3 days. Activity of the glycolytic enzymes was altered differentially in various brain structures.

Animals↗
PubMedDate not supplied

[Allosteric regulation of receptors. I. Cooperative interaction and functional regulation].

Today thousands of scientific publications in the field of receptology are dedicated to allosteric regulation of receptors. Biochemical events in cardiovascular, nerve, immune, endocrine, and other systems are based on various allosteric processes. Many of pharmaceuticals exert their action via allosteric regulation of receptive structures. Unfortunately, original publications sometimes are rather fragmentary. The history, methodology, classification as well as functional aspects of allosteric regulation of receptors are reviewed in the present paper. On the basis of topography of orthosteric and allosteric receptor binding sites allosteric regulation may be subdivided into: specific, non-specific, functional, and cooperative interaction. The results of allosteric regulation of receptors by metal cations are summarized. Agonists and antagonists receptor interaction are described from the point of view of allosteric regulation.

Allosteric Regulation↗
PubMedDate not supplied

[Role of membrane deformations in regulation of functions of cells].

There is evidence that cells respond not only to biologically active substances, but also to external mechanical effects. This is especially important for cellular elements of vascular walls and blood. Mechanical treatment cause so-called stretch-deformation of plasma membranes and forces generated by shift of plasma layers induce shear stress. Good experimental evidence exists that mechanical effects influence functional activity of vascular wall and blood cells.

Animals↗
PubMedDate not supplied

[Nitric oxide synthase activity and nitrates/nitrites level in brain regions during the spontaneous morphine withdrawal in rats].

Nitric oxide synthase (NOS) activity and nitrate/nitrites (NO(x)-) concentrations were measured in brain regions of rats during the spontaneous morphine withdrawal. Male Wistar rats were injected intraperotoneally with morphine hydrochloride at increasing doses (10-100 mg/kg) during 6 days twice a day. Thirty six hours after the last injection the severity of the spontaneous morphine withdrawal syndrome was determined by specific autonomic and locomotor indices. Both NOS activity and NO(x)- levels increased in the midbrain and the hippocampus, decreased in the striatum and the hypothalamus, and did not change in the cerebral cortex and the brain stem. NO(x)- concentrations in the cerebellum did not change, while NOS activity decreased. Both NOS activities and NO(x)- concentrations in the cerebral cortex, striatum, midbrain, and cerebellum correlated with withdrawal syndrome severity on the whole, and with the specific signs of abstinence.

Animals↗
PubMedDate not supplied

[Role of divalent cations in the structural organization of the peroxisomal membrane].

Factors, which affected the stability of peroxisomal membrane in vitro, were investigated. The decrease in the activity of catalase at neutral and alkaline pH was prevented by addition of Ca2+, Mg2+ and Ba2+; at the same time EDTA, EGTA and o-phenantroline decreased the stability of peroxisomes. All the effects were temperature-dependent. Ca2+ did not prevent the injury of peroxisomes during hypotonic lysis, but increased the electrostatic interactions of enzymes with the peroxisomal membrane. These data suggest that at neutral and alkaline pH the peroxisomal membranes had a large negative charge on their surface, which affected the stability of peroxisomes in vitro.

Acid Phosphatase↗
PubMedDate not supplied

[Labilization of lysosomal and peroxisomal membranes in the kidneys preserved by transrenal gas perfusion].

The total, free and unprecipitated activity of lysosomal (acid DNAase, acid RNAase, acid phosphate, acid beta-galactosidase) and peroxisomal (catalase, oxidase of D-amino acids) enzymes were studied in dog kidney cortex during storage of the tissues in solution of rheopolyglucin and under conservation of the kidney tissue by transrenal gas perfusion in hypothermia within 3 and 7 days. Labilization of lysosomal and peroxisomal membranes was observed during storage both in unperfused and in oxygenated kidney. Mechanisms of formation and functional significance of the alterations observed in structure of lysosomes and peroxisomes are discussed.

Acid Phosphatase↗
PubMedDate not supplied

[Effect of thiol-oxidizing agents on several enzymes in rat liver mitochondria].

The sulphydryl groups of nonprotein thiols and proteins of mitochondria, activity of enzymes, oxidative phosphorylation and swelling of these organellas were studied as affected by the thiol-oxidizing agents. Diamide and azoester are shown to oxidize SH-groups of mitochondria, inhibit isocytrate dehydrogenase and succinate: cytochrome oxidation and inhibits energy-dependent swelling of mitochondria. Under the effect of azoester the rate of oxygen consumption by mitochondria increases and there occurs their sharp swelling.

Animals↗
PubMedDate not supplied

[The effect of ethanol and the catalase inhibitor 3-amino-1,2,4-triazole on lipid peroxidation in rat liver homogenate and subcellular fractions].

Effects of repeated administration of ethanol and the catalase inhibitor 3-amino-1,2,4-triazole on the rate of Fe2+/ADP-ascorbate induced (nonenzymatic) lipid peroxidation were studied in rat liver tissue homogenate and subcellular fractions using estimation of low-level chemiluminescence and malonic dialdehyde content. The rate of lipid peroxidation was decreased in whole and nuclear-free homogenates as a result of combined or individual ethanol and aminotriazole treatment. However, this pattern was unaltered in mitochondrial and microsomal fractions. Both these agents did not affect the content of conjugated dienes in lipid containing extracts of subcellular fractions as well as the total malonic dialdehyde concentration in whole liver tissue homogenate. The data obtained suggest that antioxidative protein factor, inhibiting nonenzymatic lipid peroxidation in biological membranes, was induced in liver cytosol of rats repeatedly administered with ethanol and/or amino-triazole.

Amitrole↗
PubMedDate not supplied

[Modification by alpha-interferon of ethanol-induced changes in the level of opioid peptides in the rat striatum and hypophysis].

Content of Met-enkephalin in striatum and of beta-endorphin in rat hypophysis were estimated after administration of ethanol and alpha-interferon into the animals. Ethanol decreased Met-enkephalin content in striatum and of beta-endorphin in hypophysis. Preadministration of alpha-interferon into brain ventricles before ethanol administration led to an increase in concentration of Met-enkephalin, while content of beta-endorphin was unaltered. In peripheric administration alpha-interferon normalized content of beta-endorphin in adenohypophysis but did not affect the Met-enkephalin concentration. Effects of alpha-interferon on content of Met-enkephalin and beta-endorphin, related to dissimilar organization of the opiate systems in hypophysis and striatum tissues, are discussed.

Animals↗