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Biomedical subjects

V V Lemeshko

Publications and source records attributed to V V Lemeshko.

At least 37 records · Page 2Linked to original sources
PubMed1981

[Effect of thyroxine on the NADH cytochrome c reductase activity of microsomes and outer mitochondrial membrane of rat liver depending on age].

The rotenone-insensitive NADH-cytochrome c reductase activity and cytochrome b5 content in mitochondria and microsomes of liver of 1-, 3-, 12- and 24-month-old rats were studied. Thyroxine injection caused a considerable decrease in the microsomal activity in all age groups under study; in mitochondria this effect was increased with age. The decrease of the cytochrome b5 content was maximal in the microsomes and mitochondria of 12- and 24-month-old animals and was insignificant in 1-month-old rats. It was assumed that the age variations in regulation of the outer mitochondrial membrane function can be due changes in their population.

Aging↗
PubMed1980

[Changes in the cytochrone C and A (A3) content in the liver mitochondria of rats with hyperthyroidism].

Thyroxin was administered daily to male Wistar rats aged 1, 3, 12 and 24 months in a dose of 250 g per 100 g body weight. After 9 days there was a significant increase in the content of cytochromes c and a (a(3)). An appreciable rise in the cytochrome c content was recorded as long as after one day, whereas the content of cytochromes a (a(3)) did not exceed normal even after 2 days. Following one day the content of cytochromes a (a(3)) in 3-, 12-, and 24-month-old rats was sightly lower than in normal rats. A significant temporary increase in the c/a (a(3)) ratio was observed after 1-2 days only in 12- and 24-month-old rats. The c/a (a(3)) ratio increased with age. It is suggested that application of thyroid hormones may be promising in studies on the regulation of mitochondrial biogenesis.

Aging↗
PubMed1980

[Microsomal oxidation system in the course of development and aging].

No substantial differences in the oxidoreductase activity of the NADH-driven electron transfer chain components in the course of development and ageing of Wistar rats aged 1, 3, 12 and 24 months were found. The content or activity of separate links of the NADPH-driven chain reached their maximal values at different age periods, being decreased with ageing. The demethylase and hydroxylase activities remained unchanged upon ageing. The ratio of the NADPH-cytochrome c reductase activity to cytochrome P-450 content was decreased in 1-, 3- and 12-months-old animals.

Aging↗
PubMed1978

[Cryoresistance of rat liver endoplasmic reticulum membranes].

The effects of freezing of microsomes in liquid nitrogen and those of storage of microsomal suspensions at 2-4 degrees C and -3 - -5 degrees C for 24 hrs, on the enzymatic activities and hydrophobicity of membranes were studied. The hydrophobicity was determined by fluorescence of bound 1,8-anilino-naphthalene sulfonate. Rapid freezing of the microsomal suspension in liquid nitrogen followed by rapid warming did not change the hydrophobicity of the membranes, the rate of enzymatic lipid peroxidation, the level of cytochrome P-450 and the activity of NADH- and NADPH-cytochrome c reductase. A considerable decrease in the rate of enzymatic lipid peroxidation and membrane hydrophobicity was observed in the microsomes stored for 24 hrs at 2-4 degrees C. The 24-hr storage at -3 - -5 degrees C with subsequent thawing resulted in a rapid aggregation of the microsomes.

Adaptation, Physiological↗
PubMed1976

[Halidor, 1-benzyl-1-(3'-dimethylaminopropoxy)-cyclohep tane fumarate as an uncoupler and inhibitor of the respiratory chain].

Halidor 1-benzyl-1-(3'-dimethylaminopropoxy)-cycloheptane fumarate, activates succinate oxidation in mitochondria and inhibits reverse electron transport from succinate to NAD+ in submitochondrial partides preparations at doses of 2-10(-5)--10(-3) M. At a dose of 5--7-10(-4) M halidor cause a swelling of mitochondria incubated in 0.1 M NH4NO3. At higher concentrations (10(-3)--10(-2) M) halidor practically completely inhibits NADH and succinate oxidase activity of mitochondria and submitochondrial particles. It is suggested that vasodilating effect of halidor is due to the uncoupling of oxidative phosphorylation, thus causing a deficiency of ATP for contracting function of blood vessel muscles.

Adenosine Triphosphate↗
PubMedDate not supplied

[Effects of different regimes of freezing and thawing on chemiluminescence of rat liver mitochondria].

The rate of Fe2+ activated lipid peroxidation was studied as affected by the different freezing-thawing regime. The level of peroxidation was judged by kinetics and superfeeble luminiscence intensity of mitochondria. It was shown that freezing up to -196 degrees C and subsequent thawing of the mitochondria suspended in a salty medium (KCl) results in an increase in the rate of lipid peroxidation. A more distinct response to the introduction of peroxidation activator (Fe2SO4) is observed in mitochondria, especially in the first 1-2 minutes after ion introduction - in the phase of "slow flash". Besides, there is an increase in the level of stationary luminescence (2-10, 12-22 min) of the frozen-thawed mitochondria in comparison with the control. Slow thawing of quickly or slowly frozen mitochondria results in a more considerable increase in the luminescence light sum, than in the case of rapid thawing. The least-luminescence intensity after freezing and thawing of mitochondria suspension was observed after the rapid freezing and rapid thawing. In case of slow thawing the rate of mitochondria freezing does not considerably affect the degree of chemiluminescence.

Animals↗
PubMedDate not supplied

[The effect of osmotic pressure on oligomycin-sensitive ATPase activity and the liberation of Mg2+ from liver mitochondria of rats of various ages].

The influence of osmotic pressure of the incubating medium (25-500 mM sucrose) on oligomycin--sensitive, 2,4-dinitrophenyl-stimulated ATP-ase-activity, Mg2+ release and swelling of the liver mitochondria in 1-, 3-, 12-, 24-months Wistar rats is, investigated to determine age changes of structurally functional state of mitochondria. An increase in the sucrose concentration in the medium from 150 to 500 mM causes almost equal and practically absolute inhibition of ATP-ase-activity in different-age groups of rats, regardless of the presence or absence of Mg2+ ions in the medium A fall of the sucrose concentration to 150-25 mM induces a decrease in mitochondria ATP-ase-activity in Mg2+ free medium in 12- and 24-months rats (to 30 and 22%, respectively). No changes are observed in 1- and 3-months animals. Differences in rates of exogenous NADH oxidation by mitochondria of 1- and 12-months rats as a reflection of inner membrane damage degree are not observed under these conditions. Relative changes in ATP-ase-activity in a Mg2+ free medium with sucrose concentration of 25 mM (compared with 150 mM) correlate (r = 0.82) with those of optical density of mitochondria, measured at light wave length of 520 nm. It is obvious that the liver mitochondria of young and old rats sufficiently differ in spontaneous swelling rate in the media with different osmotic pressure: mitochondria of 1-month rats swell much faster than those of old rats. Considerable age differences of osmotic dependence of Mg2+ output from mitochondria are observed. They depend also on peculiarities of spontaneous organelle swelling dynamics.(ABSTRACT TRUNCATED AT 250 WORDS)

2,4-Dinitrophenol↗
PubMedDate not supplied

[A simple method for estimation of phospholipids in biological objects].

A simple method to estimate phospholipids is elaborated. This method is based on determination of optical density of phospholipid-molybdate complexes in chloroform. The method is used for the quantitative determination of phospholipids in biomembranes, liposomes and blood serum without their preliminary extraction, as well as in chloroform, methanol and chloroform-methanol solutions. It is also modified for the phospholipids determination in chromatographic fractions on silufol plates.

Animals↗
PubMedDate not supplied

[Mg2+ release from heart mitochondria in ischemia: is it the defense mechanism or damage?].

It is established that at the early stage of total heart ischemia in rats (5-10 min) the oligomycin-sensitive ATPase activity of mitochondria measured in heart homogenates in the medium and containing no Mg2+ decreases considerably, whereas the activity of respiratory chain, the value of respiratory control and Mg2+-ATPase activity are practically unchanged. The hypothetic trigger mechanism is suggested for Mg2+ ejection from mitochondria under conditions of respiration cessation. It is supposed to be a defence reaction of cells aimed to prevent ATP hydrolysis by mitochondria under ischemia.

Animals↗
PubMedDate not supplied

[The effect of tetracycline and silibore on lipid peroxidation in the liver od rats of various age].

As shown by accumulation of malonic dialdehyde and chemiluminescence rate monitoring tetracycline activated both NADPH- and ascorbate-dependent lipid peroxidation in liver tissue of 1, 3, 12 and 24 months old rats. The most distinct induction of lipid peroxidation was observed in old animals, which appears to occur due to a decrease in efficiency of NADPH-GSH-dependent enzymatic antioxidant system. Silibore prevented the stimulating effect of tetracycline on enzymatic and nonenzymatic lipid peroxidation, being apparently involved in hepatoprotective effect.

Aging↗
PubMedDate not supplied

[Features of ischemic injuries to membranes and activation of lipid peroxidation in the myocardium of rats of various ages].

The model of interrupted ischemia of the isolated heart has been used to show that the yield of lactate dehydrogenase into perfusate in experiments on old rats is described by more sharply pronounced S-like dependence than that in young immature animals. The activation of lipid peroxidation precedes the sarcolemma damage and is relatively more manifested in rats of middle and old age. The respiratory control of mitochondria (in homogenates) decreases considerably already 20 min after ischemia, however mitochondria retain their ability to synthesize ATP 3 h later as well. The causal-effect relationship between the activation of lipid peroxidation and partial disturbance of the mitochondrial function remains unclear.

Adenosine Triphosphate↗
PubMedDate not supplied

[Peroxidation of biomembrane lipids and its enzymatic regulation during aging in the rat].

Measurement of the intensity of chemiluminescence and accumulation of the peroxidation products detected in the reaction with thiobarbituric acid (TBA-active products) has shown that with the ageing of rats the intensity of peroxidation of biomembranes' lipids gets lower in the liver and heart homogenates and tends to decrease in the brain homogenates. A strict correlation is established to exist between the level of TBA-active products and the chemiluminescence intensity independent of the age, organ and the method of initiation of lipids' peroxidation and its intensity. Considerable age changes in the rate of lipids' peroxidation in the liver and heart homogenates may be associated with an increase in the activity of a number of such antioxidant enzymes as superoxide dismutase, glutathione peroxidase, glutathione transferase and catalase in the postnatal ontogenesis of rats.

Aging↗
PubMedDate not supplied

[Prolonged storage of "firmly conjugated" mitochondria in liquid nitrogen].

A method is described to obtain mitochondria whose matrix at the stage of organella washing is saturated by dimethyl sulphoxide in the concentration necessary to prevent the cryodamage of membranes. Such mitochondria, being frozen and stored in liquid nitrogen, retain the value of a respiratory control of the coefficient ADP/O and the respiratory chain activity for 1.0-1.5 and more months.

Animals↗
PubMedDate not supplied

[Lipid hydroperoxide levels in the heart and liver of rats of various ages].

The level of lipid hydroperoxides and secondary products of peroxide oxidation of lipids reacting with 2-thiobarbituric acid (TBA) has been studied in the heart and liver of Wistar male rats aged 1, 3, 12 and 24 months. It is shown that the both indices in the heart lower in the pubertal period of ontogenesis and do not vary with the further ageing. The content of hydroperoxides in the liver is unchanged and that of secondary TBA-active products decreases with the age.

Aging↗