Dynamics of changes in skin lipids after stress: Effects of exogenous melatonin

Changes in the skin lipid composition induced by water-immersion stress in rats treated and untreated with melatonin were studied by thin-layer chromatography. Skin lipids showed a delayed reaction to stress. Melatonin exerted a protective effect which was manifested on the 2nd day after treatment in restoration of the level of total lipids and the absolute content of the majority of lipid fractions. The data suggest modification of, the metabolic relationships between skin lipids as well as lipids of the blood and subcutaneous adipose tissue. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 5, pp. 519–522, May, 1999     

Lipid spectrum of erythrocyte membranes in cancer patients

In patients with untreated tumors (lung cancer, head and neck tumors, stomach and colon cancer), erythrocyte membranes are characterized by a decreased content of total lipids together with increased percentage of cholesterol and lysophosphatidylcholine in comparison with healthy individuals. The observed shifts depend on tumor location. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 8, pp. 204–206, August, 1998     

DNA-Bound lipids of thermoresistant and thermolabileShigella sonnei strains

Thin-layer chromatography of DNA-bound lipids of thermolabile and thermoresistantShigella sonnei strains shows a lower content of neutral lipids and higher contents of polyglycerophosphatides and cholesterol in thermoresistant strains. This is regarded as a factor providing for the active state of DNA. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 332–333, September, 1995     

Effect of a long low-power γ-irradiation and β-carotene on lipid metabolism in the rat thymocyte nuclei

The effect of γ-irradiation in a dose of 1.5 Gy at a dose intensity of 3 sGy/day on the rat thymocyte nuclear lipids and of β-carotene diet on the metabolism of thymocyte nuclear lipids is studied in intact and γ-irradiated rats. The irradiation activated the incorporation of 2-¹⁴C-acetate in the total lipid fraction and in cholesterol and suppressed the label incorporation in sphyngomyelin. The β-carotene diet decreased the content of cholesterol and monoglycerides in the thymocyte nuclei of intact and irradiated rats. In irradiated rats β-carotene increased the label incorporation in the total phosphatidylserine+phosphatidylinositol fraction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 311–313, September, 1998     

Effects of saltwort plants on blood plasma lipids in rats during chronic alcohol intoxication and after ethanol withdrawal

Saltwort plants (salsocollin) ameliorated plasma contents of total lipids, triacylglycerols, and phosphatidylcholine in rats with alcohol intoxication, but had no effect on cholesterol and total phospholipid levels. Salsocollin did not prevent the increase in the levels of total lipids and triacylglycerols 3 days after ethanol withdrawal. During abstinence, salsocollin potentiated symptoms of ethanol withdrawal (7 days later) in relation to the content of total phospholipids, but normalized the levels of phosphatidylcholine, phosphatidylethanolamine, and total lipids. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 665–667, June, 1999     

Effect of oxidized cholesterol derivatives on lymphokine-stimulated macrophage differentiation and primary allogenic mixed culture of human lymphocytes

Products of cholesterol oxidation, 25-hydroxycholesterol and 7-ketocholesterol, in a dose of 1 μg/ml considerably suppress proliferative response in a primary one-way mixed culture of human lymphocytes and have no effect on spontaneous proliferation. Preliminary 18-h separate culturing of the stimulator and responders with these lipids shows that inhibiting effect of these lipids on cell proliferation is associated with their influence on both stimulator and, to a greater extent, responders. Both lipids in the same dose inhibit accumulation of HLA-DR-positive macrophages in a 4-day culture of peripheral blood adherent cells stimulated with lymphokine-containing supernatant. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 12, pp. 655–657, December, 1997     

Melatonin as a geroprotector: Experiments withDrosophila melanogaster

The lifespan ofD. melanogaster treated with melatonin in a concentration of 0.08% at the stage of development is studied. The geroprotective effect of melatonin is the most obvious (up to 12–18%) in comparison with controls with a short lifespan; if the controls' lifespan was relatively long, the hormone exerts negligible or toxic effect shortening the lifespan by up to 10%. Antioxidant mechanism of geroprotective effect of melatonin is discussed in light of the concept of fluctuations in the lifespan in successiveD. melanogaster generations. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 2, pp. 205–207, February, 1999     

Lipid peroxidation level in the focus of compression ischemia in the cerebral cortex of rats

Pathomorphological changes in a focus of ischemia, the level of lipid peroxidation (as indicated by the content of products reacting with thiobarbituric acid), and the postischemic levels of adenyl nucleotides and tissue lipids were studied in rats with focal compression ischemia of the cerebral cortex. An increased level of the TBA-reactive products paralleled by a reduction of the concentrations of adenyl nucleotides and tissue lipids was found to be in clear-cut correlation with the processes of neuronal injury and death and with subsequent repair phenomena in the focus of cortical ischemia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 589–590, December, 1994 Presented by O. S. Adrianov, Member of the Russian Academy of Medical Sciences     

Melatonin and ulceration in rat stomach in acute emotional stress

Formation of peptic ulcers under conditions of acute emotional stress was studied in rats injected with different doses of melatonin (0.5, 1, and 2 mg/kg). The number of total length of peptic ulcers increases under conditions of stress. In unstressed rats melatonin induces ulceration of gastric mucosa. In a dose of 1 mg/kg melatonin exerts protective effect on gastric mucosa. No significant changes in the number and total length of peptic ulcers are noted with 0.5 and 2 mg/kg melatonin. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 1, pp. 12–14, January, 1998     

Extrapineal melatonin and its role in the neuroendocrine regulation of homeostasis

The hormone of melatonin is the main regulator of biological rhythms. It was first found in the pineal gland in 1958. Melatonin is involved in the regulation of many vital physiological processes: maturation and development of genitalias, metabolism of pigments and free radicals, immune response, mood and sleep, and cell proliferation and differentiation. The pineal gland is not the only organ synthesizing melatonin. Extrapineal melatonin is widely dis-tributed in humans and animals. Melatonin-producing cells are found in the gastrointestinal and respiratory tracts, pancreas, adrenal and thyroid glands, thymus, cerebellum, urogenital system, placenta, and other organs. Melatonin is intensely synthesized in non-endocrine cells: mast cells, natural killers, eosinophilic leukocytes, platelets, and endotheliocytes. Such a wide distribution of melatonin reflects its key role as an intercellular neuroendocrine regulator and coordinator of many complex and interrelated biological processes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 4, pp. 364–730, April, 1999     

Effect of melatonin on cyclic nucleotide content and intensity of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypoxia

Single intraperitoneal injection of melatonin in a dose of 1 mg/kg prevented accumulation of cGMP and intensification of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypobaric hypoxia (12,000 m). Changes in habenular content of cGMP suggest that melatonin prevents hypoxia-induced activation of heme-oxygenase. Translated fromByulleten' Eksperimental" noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 168–171, August, 2000     

Effect of hyperlipidemia on thymocyte sensitivity to apoptosis in CBA and C57Bl/6 mice

Effects of experimental hyperlipidemia on apoptosis and proliferation of thymocytes in response to mitogens were studied in CBA and C57Bl/6 mice. The concentrations of cholesterol in the serum and thymocyte membranes increased in both mouse strains. Spontaneous and dexamethasone-induced apoptosisin vitro and the proliferative response to phytohemagglutinin and concanavalin A were enhanced in thymocytes from C57Bl/6 mice and suppressed in cells from CBA mice. These data suggest opposite reactions of thymocyte to increased serum cholesterol concentration in these two strains, associated with stimulation and suppression of cell activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 200–202, August, 2000     

Enhanced blood activity of selenic glutathione peroxidase in patients with coronary heart disease after treatment with selenium-containing antioxidant preparation adrusen zinco

This study analyzed the effects of nutriceutic Adrusen Zinco containing vitamin E and prosthetic groups of antioxidant enzymes (selenium, copper, zinc) on the parameters of free radical oxidation of blood lipids in patients with coronary heart disease and hypercholesterolemia. Adrusen Zinco considerably increased activity of erythrocyte and serum selenic glutathione peroxidase as soon as after 1-month treatment, while erythrocyte SOD activity significantly increased only after 2 months. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 3, pp. 277–279, March, 2000     

Effects of S-adenosyl methionine, ethanolamine, and their combination on lipid composition of rat brain in chronic alcohol intoxication

Brain lipids are studied in rats with chronic alcohol intoxication after injection of S-adenosyl methionine, ethanolamine, and their combination. The levels of total lipids, phospholipids, and cardiolipin are increased and those of sphyngomyelin and cerebrosides-III decreased after a 14-day inhalation of ethanol. Combined administration of S-adenosyl methionine and ethanolamine in chronic alcoholization eliminated ethanol-induced shifts in concentrations of phospho- and glycolipid fractions in rat brain. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 4, pp. 398–400, April, 1998     

Altered impedance during pigment aggregation in<Emphasis Type="Italic">Xenopus laevis</Emphasis> melanophores

Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.     

Dynamics of formation of primary and secondary lipid peroxidation products upon copper-dependent oxidation of low-density lipoproteins isolated from blood serum of patients with ischemic heart disease

The kinetics of copper-induced oxidation of lipids in serum low-density lipoproteins from healthy subjects and patients with ischemic heart disease and documented coronary atherosclerosis is studied. After a 4-h incubation with 40 μM CuSO₄, the oxidizability of patients' lipoproteins is higher, judging from the contents of diene conjugates and oxidation products reacting with thiobarbituric acid. Intergroup differences in the kinetics of the diene conjugate formation are revealed. Statistical analysis shows that in all studied individuals there is no relationship between the oxidizability of low-density lipoproteins and the cholesterol content in lipoproteins and serum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 32–36, July, 1996     

Altered Circadian Rhythms of the Stress Hormone and Melatonin Response in Lupus-prone MRL/MP-fas Mice

The immune system interacts with the hypothalamo-pituitary-adrenal axis via so-called glucocorticoid increasing factors, which are produced by the immune system during immune reactions, causing an elevation of systemic glucocorticoid levels that contribute to preservation of the immune reactions specificities. Previous results from our laboratory had already shown an altered immuno-neuroendocrine dialogue via the hypothalamo-pituitary-adrenal axis in autoimmune disease-prone chicken and mouse strains. In the present study, we further investigated the altered glucocorticoid response via the hypothalamo-pituitary-adrenal axis in murine lupus. We established the circadian rhythms of corticosterone, dehydroepiandrosterone-sulfate, adrenocorticotropic hormone and melatonin, as well as the time response curves after injection of interleukin-1 of the first three parameters in normal SWISS and lupus-prone MRL/MP- fas^Iprmice. The results show that lupus-prone MRL/MP- fas^Iprmice do not react appropriately to changes of the light/dark cycle, circadian melatonin rhythms seem to uncouple from the light/dark cycle, and plasma corticosterone levels are elevated during the resting phase. Diurnal changes of dehydroepiandrosterone-sulfate and adrenocorticotropic hormone were normal compared to healthy controls. These data indicate that MRL/ MP- fas^Iprmice not only show an altered glucocorticoid response mediated via the hypothalamo pituitary adrenal axis to IL-1, but are also affected by disturbances of corticosterone and melatonin circadian rhythms. Our findings may have implications for intrathymic T cell development and the emergence of autoimmune disease.     

Melatonin potentiates the GABAA receptor-mediated current in cultured chick spinal cord neurons

The effect of melatonin on the γ-aminobutyric acid_A (GABA_A) receptor-mediated response was studied in cultured chick spinal cord neurons using the whole-cell voltage-clamp recording technique. Melatonin rapidly and reversibly potentiated the GABA-induced current in a dose-dependent fashion, with an EC₅₀ of 766 μM and a maximal potentiation of 148%. Potentiation of the GABA response by melatonin was mediated by increasing the potency of GABA rather than the efficacy. Prolonged exposure to a saturating concentration of the disulfide-reducing agent dithiothreitol did not attentuate the effect of melatonin on the GABA response, indicating that melatonin does not act through the redox site. Furthermore, our results demonstrate that melatonin and 5α-pregnan-3α-ol-20-one (a positive steroid modulator of the GABA_A receptor) act through different sites.     

Effect of ozone on the liver in experimental chronic hepatitis

Short-term administration of ozonized physiological solution to rats with chronic toxic hepatitis reduces the content of total lipids in the liver tissue, activates antioxidant enzymes, normalizes the level of diene conjugates, and reliably increases adenosine nucleotides, the number of normal hepatocytes being increased 2.2-fold. The data suggest that ozone can be used as a stimulator of regeneration of the pathologically altered liver. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 8, pp. 238–240, August, 1996     

Effect of picrotoxin-induced seizures on lipid composition of cortical tissue homogenate and its nuclear fraction in rats

The content of lipids in rat cortical tissue homogenate and fraction of neuronal nuclei was determined under normal conditions and after picrotoxin-induced seizures. Changes in lipid composition of homogenate and nuclear fraction differed considerably. In homogenate, the content of sphingomyelin, lysophosphatidylcholine, and total phospholipids increased, while the content of free fatty acid remained unchanged; in the nuclear fraction the total phospholipid content decreased, while the concentration of free fatty acids increased. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 292–294, September 2000