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Sample records for nitric oxide-mediated cyclic

  1. Nitrate tolerance impairs nitric oxide-mediated vasodilation in vivo

    DEFF Research Database (Denmark)

    Laursen, Jørn Bech; Boesgaard, Søren; Poulsen, Henrik E.;

    1996-01-01

    Nitrates, Nitrate tolerence, Nitric oxide, acetylcholine, N-acetylcholine, N-acetylcysteine, L-NAME, Rat, Anesthetized......Nitrates, Nitrate tolerence, Nitric oxide, acetylcholine, N-acetylcholine, N-acetylcysteine, L-NAME, Rat, Anesthetized...

  2. Nitric Oxide-Mediated Posttranslational Modifications: Impacts at the Synapse

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    Sophie A. Bradley

    2016-01-01

    Full Text Available Nitric oxide (NO is an important gasotransmitter molecule that is involved in numerous physiological processes throughout the nervous system. In addition to its involvement in physiological plasticity processes (long-term potentiation, LTP; long-term depression, LTD which can include NMDAR-mediated calcium-dependent activation of neuronal nitric oxide synthase (nNOS, new insights into physiological and pathological consequences of nitrergic signalling have recently emerged. In addition to the canonical cGMP-mediated signalling, NO is also implicated in numerous pathways involving posttranslational modifications. In this review we discuss the multiple effects of S-nitrosylation and 3-nitrotyrosination on proteins with potential modulation of function but limit the analyses to signalling involved in synaptic transmission and vesicular release. Here, crucial proteins which mediate synaptic transmission can undergo posttranslational modifications with either pre- or postsynaptic origin. During normal brain function, both pathways serve as important cellular signalling cascades that modulate a diverse array of physiological processes, including synaptic plasticity, transcriptional activity, and neuronal survival. In contrast, evidence suggests that aging and disease can induce nitrosative stress via excessive NO production. Consequently, uncontrolled S-nitrosylation/3-nitrotyrosination can occur and represent pathological features that contribute to the onset and progression of various neurodegenerative diseases, including Parkinson’s, Alzheimer’s, and Huntington’s.

  3. Hemoglobin Effects on Nitric Oxide Mediated Hypoxic Vasodilation.

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    Rong, Zimei; Cooper, Chris E

    2016-01-01

    The brain responds to hypoxia with an increase in cerebral blood flow (CBF). However, such an increase is generally believed to start only after the oxygen tension decreases to a certain threshold level. Although many mechanisms (different vasodilator and different generation and metabolism mechanisms of the vasodilator) have been proposed at the molecular level, none of them has gained universal acceptance. Nitric oxide (NO) has been proposed to play a central role in the regulation of oxygen supply since it is a vasodilator whose production and metabolism are both oxygen dependent. We have used a computational model that simulates blood flow and oxygen metabolism in the brain (BRAINSIGNALS) to test mechanism by which NO may elucidate hypoxic vasodilation. The first model proposed that NO was produced by the enzyme nitric oxide synthase (NOS) and metabolized by the mitochondrial enzyme cytochrome c oxidase (CCO). NO production declined with decreasing oxygen concentration given that oxygen is a substrate for nitric oxide synthase (NOS). However, this was balanced by NO metabolism by CCO, which also declined with decreasing oxygen concentration. However, the NOS effect was dominant; the resulting model profiles of hypoxic vasodilation only approximated the experimental curves when an unfeasibly low K m for oxygen for NOS was input into the model. We therefore modified the model such that NO generation was via the nitrite reductase activity of deoxyhemoglobin instead of NOS, whilst keeping the metabolism of NO by CCO the same. NO production increased with decreasing oxygen concentration, leading to an improved reproduction of the experimental CBF versus PaO2 curve. However, the threshold phenomenon was not perfectly reproduced. In this present work, we incorporated a wider variety of oxygen dependent and independent NO production and removal mechanisms. We found that the addition of NO removal via oxidation to nitrate mediated by oxyhemoglobin resulted in the

  4. Nitric oxide mediates gravitropic bending in soybean roots.

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    Hu, Xiangyang; Neill, Steven J; Tang, Zhangcheng; Cai, Weiming

    2005-02-01

    Plant roots are gravitropic, detecting and responding to changes in orientation via differential growth that results in bending and reestablishment of downward growth. Recent data support the basics of the Cholodny-Went hypothesis, indicating that differential growth is due to redistribution of auxin to the lower sides of gravistimulated roots, but little is known regarding the molecular details of such effects. Here, we investigate auxin and gravity signal transduction by demonstrating that the endogenous signaling molecules nitric oxide (NO) and cGMP mediate responses to gravistimulation in primary roots of soybean (Glycine max). Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip. Fluorescence confocal microcopy revealed that the accumulation of NO was asymmetric, with NO concentrating in the lower side of the root. Removal of NO with an NO scavenger or inhibition of NO synthesis via NO synthase inhibitors or an inhibitor of nitrate reductase reduced both NO accumulation and gravitropic bending, indicating that NO synthesis was required for the gravitropic responses and that both NO synthase and nitrate reductase may contribute to the synthesis of the NO required. Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips. Gravistimulation, NO, and auxin also induced the accumulation of cGMP, a response inhibited by removal of NO or by inhibitors of guanylyl cyclase, compounds that also reduced gravitropic bending. Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor, and the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP, a cell-permeable analog of cGMP. These data indicate that auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots.

  5. Nitric oxide mediates the stress response induced by diatom aldehydes in the sea urchin Paracentrotus lividus.

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    Giovanna Romano

    Full Text Available Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms.

  6. Nitric oxide mediates the stress response induced by diatom aldehydes in the sea urchin Paracentrotus lividus.

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    Romano, Giovanna; Costantini, Maria; Buttino, Isabella; Ianora, Adrianna; Palumbo, Anna

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms.

  7. Nitric oxide-mediated endothlium-dependent vasodilation is impaired with borderline high-LDL cholesterol.

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    Diehl, Kyle J; Stauffer, Brian L; Greiner, Jared J; Weil, Brian R; DeSouza, Christopher A

    2012-02-01

    The experimental aims of this study were to determine: (1) whether nitric oxide-mediated endothelium-dependent vasodilation is blunted in adult humans with borderline high plasma low-density lipoprotein (LDL)-cholesterol compared with adults with optimal/near optimal LDL-cholesterol levels; and, if so: (2) whether the magnitude of impairment in adults with borderline high LDL-cholesterol is similar to adults with high LDL-cholesterol. Forearm blood flow responses to intraarterial infusions of acetylcholine and sodium nitroprusside were measured in 50 middle-aged (43-64 year) adults: 20 in the optimal/near optimal LDL-cholesterol range (<130 mg/dL); 20 with borderline high LDL-cholesterol (130-159 mg/dL); and 10 with high LDL-cholesterol ($160 mg/dL). In addition, blood flow responses to acetylcholine were determined in the absence and presence of the endothelial nitric oxide synthase inhibitor N(G) -monomethyl-L-arginine (L-NMMA). Vasodilation to acetylcholine was ~20% lower (p < 0.05) in the borderline high (from 4.3 ± 0.2 to 12.3 ± 0.8 mL/100 mL tissue/min) and high (from 4.3 ± 0.3 to 12.0 ± 0.5 mL/100 mL tissue/min) LDL-cholesterol groups compared with the optimal/near optimal (from 4.4 ± 0.2 to 14.5 ± 0.5 mL/100 mL tissue/min) LDL-cholesterol group. L-NMMA significantly reduced (~30%) the vasodilator response to acetylcholine in the optimal/near optimal LDL-cholesterol group but not the borderline high or high LDL-cholesterol groups. Borderline high LDL-cholesterol is associated with impaired nitric oxide-mediated endothelium-dependent vasodilation.

  8. Nitric oxide-mediated protein modification in cardiovascular physiology and pathology.

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    Gödecke, Axel; Schrader, Jürgen; Reinartz, Michael

    2008-06-01

    Nitric oxide (NO) is a key regulator of cardiovascular functions including the control of vascular tone, anti-inflammatory properties of the endothelium, cardiac contractility, and thrombocyte activation and aggregation. Numerous experimental data support the view that NO not only acts via cyclic guanosine monophosphate (cGMP)-dependent mechanisms but also modulates protein function by nitrosation, nitrosylation, glutathiolation, and nitration, respectively. To understand how NO regulates all of these diverse biological processes on the molecular level a comprehensive assessment of NO-mediated cGMP-dependent and independent targets is required. Novel proteomic approaches allow the simultaneous identification of large quantities of proteins modified in an NO-dependent manner and thereby will considerably deepen our understanding of the role NO plays in cardiovascular physiology and pathophysiology.

  9. Nitric oxide-mediated changes in vascular reactivity in pregnancy in spontaneously hypertensive rats.

    OpenAIRE

    Chu, Z. M.; Beilin, L J

    1993-01-01

    1. To examine the mechanisms which may account for pregnancy-induced vasodilatation in spontaneously hypertensive rats (SHR), we have investigated the changes in vascular reactivity and the effects of endothelial nitric oxide (NO) inhibition in the in situ blood-perfused, mesenteric resistance vessels of 18-20 day pregnant SHR. The effects of NG-nitro-L-arginine (L-NOARG) were compared in pregnant and nonpregnant SHR and gestation matched normotensive Wistar-Kyoto (WKY) rats. 2. Intra-arteria...

  10. Nitric Oxide Mediates the Stress Response Induced by Diatom Aldehydes in the Sea Urchin Paracentrotus lividus

    OpenAIRE

    Giovanna Romano; Maria Costantini; Isabella Buttino; Adrianna Ianora; Anna Palumbo

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadie...

  11. Nitric oxide mediates low magnesium inhibition of osteoblast-like cell proliferation.

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    Leidi, Marzia; Dellera, Federica; Mariotti, Massimo; Banfi, Giuseppe; Crapanzano, Calogero; Albisetti, Walter; Maier, Jeanette A M

    2012-10-01

    An adequate intake of magnesium (Mg) is important for bone cell activity and contributes to the prevention of osteoporosis. Because (a) Mg is mitogenic for osteoblasts and (b) reduction of osteoblast proliferation is detected in osteoporosis, we investigated the influence of different concentrations of extracellular Mg on osteoblast-like SaOS-2 cell behavior. We found that low Mg inhibited SaOS-2 cell proliferation by increasing the release of nitric oxide through the up-regulation of inducible nitric oxide synthase (iNOS). Indeed, both pharmacological inhibition with the iNOS inhibitor l-N(6)-(iminoethyl)-lysine-HCl and genetic silencing of iNOS by small interfering RNA restored the normal proliferation rate of the cells. Because a moderate induction of nitric oxide is sufficient to potentiate bone resorption and a relative deficiency in osteoblast proliferation can result in their inadequate activity, we conclude that maintaining Mg homeostasis is relevant to ensure osteoblast function and, therefore, to prevent osteoporosis.

  12. Different sources of nitric oxide mediate neurovascular coupling in the lateral geniculate nucleus of the cat

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    Carmen De Labra

    2009-09-01

    Full Text Available Understanding the link between neuronal responses and metabolic signals is fundamental to our knowledge of brain function and it is a milestone in our efforts to interpret data from modern non invasive optical techniques such as fMRI, which are based on the close coupling between metabolic demand of active neurons and local changes in blood flow. The challenge is to unravel the link. Here we show, using spectrophotometry to record oxyhemoglobin (OxyHb and metahemoglobin (MetHb (surrogate markers of cerebral flow and nitric oxide levels respectively together with extracellular neuronal recordings in vivo and applying a multiple polynomial regression model, that the markers are able to predict up about 80% of variability in neuronal response. Furthermore, we show that the coupling between blood flow and neuronal activity is heavily influenced by nitric oxide (NO. While neuronal responses show the typical saturating response, blood flow shows a linear behaviour during contrast-response curves, with nitric oxide from different sources acting differently for low and high intensity.

  13. Nitric oxide-mediated intracellular growth restriction of pathogenic Rhodococcus equi can be prevented by iron.

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    von Bargen, Kristine; Wohlmann, Jens; Taylor, Gregory Alan; Utermöhlen, Olaf; Haas, Albert

    2011-05-01

    Rhodococcus equi is an intracellular pathogen which causes pneumonia in young horses and in immunocompromised humans. R. equi arrests phagosome maturation in macrophages at a prephagolysosome stage and grows inside a privileged compartment. Here, we show that, in murine macrophages activated with gamma interferon and lipopolysaccharide, R. equi does not multiply but stays viable for at least 24 h. Whereas infection control of other intracellular pathogens by activated macrophages is executed by enhanced phagosome acidification or phagolysosome formation, by autophagy or by the interferon-inducible GTPase Irgm1, none of these mechanisms seems to control R. equi infection. Growth control by macrophage activation is fully mimicked by treatment of resting macrophages with nitric oxide donors, and inhibition of bacterial multiplication by either activation or nitric oxide donors is annihilated by cotreatment of infected macrophages with ferrous sulfate. Transcriptional analysis of the R. equi iron-regulated gene iupT demonstrates that intracellular R. equi encounters iron stress in activated, but not in resting, macrophages and that this stress is relieved by extracellular addition of ferrous sulfate. Our results suggest that nitric oxide is central to the restriction of bacterial access to iron in activated macrophages.

  14. Nitric Oxide-Mediated Intracellular Growth Restriction of Pathogenic Rhodococcus equi Can Be Prevented by Iron▿

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    von Bargen, Kristine; Wohlmann, Jens; Taylor, Gregory Alan; Utermöhlen, Olaf; Haas, Albert

    2011-01-01

    Rhodococcus equi is an intracellular pathogen which causes pneumonia in young horses and in immunocompromised humans. R. equi arrests phagosome maturation in macrophages at a prephagolysosome stage and grows inside a privileged compartment. Here, we show that, in murine macrophages activated with gamma interferon and lipopolysaccharide, R. equi does not multiply but stays viable for at least 24 h. Whereas infection control of other intracellular pathogens by activated macrophages is executed by enhanced phagosome acidification or phagolysosome formation, by autophagy or by the interferon-inducible GTPase Irgm1, none of these mechanisms seems to control R. equi infection. Growth control by macrophage activation is fully mimicked by treatment of resting macrophages with nitric oxide donors, and inhibition of bacterial multiplication by either activation or nitric oxide donors is annihilated by cotreatment of infected macrophages with ferrous sulfate. Transcriptional analysis of the R. equi iron-regulated gene iupT demonstrates that intracellular R. equi encounters iron stress in activated, but not in resting, macrophages and that this stress is relieved by extracellular addition of ferrous sulfate. Our results suggest that nitric oxide is central to the restriction of bacterial access to iron in activated macrophages. PMID:21383050

  15. Inhibition of nitric oxide mediated protein nitration: therapeutic implications in experimental radiculopathy.

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    Lee, Seong Jae; Kim, Tae Uk; Park, Jeong-Soo; Ra, Jong Yun

    2013-09-15

    Experimental animal study. This study investigated whether nitric oxide (NO) mediated protein nitration is involved in the pathogenesis of radiculopathy and whether the symptoms can be relieved by its suppression. It has been reported that nitration of protein mediated by NO is involved in the degenerative neurological disorders, but its involvement is not clear in the radiculopathy. Two kinds of rat models of radiculopathy were used. Radiculopathy was induced either by ligation of spinal nerve roots or transplantation of autologous nucleus pulposus. In separate groups of rats, aminoguanidine, a potent nitric oxide synthetase inhibitor, was administered just before induction of radiculopathy, to suppress NO production and resultant nitration of protein. Sensation of the hind limb was evaluated by plantar stimulation test, and motor weakness was assessed by observation of gait pattern. Nitrotyrosine, product of protein nitration, was assayed quantitatively by Western immunoblotting. Mechanical allodynia was observed in both compression and nucleus pulposus groups, but motor weakness was observed only in the compression group. Preoperative administration of aminoguanidine attenuated mechanical allodynia and motor weakness. Optical densities of nitrotyrosine bands increased significantly in radiculopathy groups, but they were lowered by administration of aminoguanidine. NO mediated protein nitration contributes to the development of both types of radiculopathies. Suppression of NO production can decrease protein nitration and relieve neural dysfunctions of radiculopathy. N/A.

  16. The endogenous nitric oxide mediates selenium-induced phytotoxicity by promoting ROS generation in Brassica rapa.

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    Yi Chen

    Full Text Available Selenium (Se is suggested as an emerging pollutant in agricultural environment because of the increasing anthropogenic release of Se, which in turn results in phytotoxicity. The most common consequence of Se-induced toxicity in plants is oxidative injury, but how Se induces reactive oxygen species (ROS burst remains unclear. In this work, histofluorescent staining was applied to monitor the dynamics of ROS and nitric oxide (NO in the root of Brassica rapa under Se(IV stress. Se(IV-induced faster accumulation of NO than ROS. Both NO and ROS accumulation were positively correlated with Se(IV-induced inhibition of root growth. The NO accumulation was nitrate reductase (NR- and nitric oxide synthase (NOS-dependent while ROS accumulation was NADPH oxidase-dependent. The removal of NO by NR inhibitor, NOS inhibitor, and NO scavenger could alleviate Se(IV-induced expression of Br_Rbohs coding for NADPH oxidase and the following ROS accumulation in roots, which further resulted in the amelioration of Se(IV-induced oxidative injury and growth inhibition. Thus, we proposed that the endogenous NO played a toxic role in B. rapa under Se(IV stress by triggering ROS burst. Such findings can be used to evaluate the toxic effects of Se contamination on crop plants.

  17. Role of nitric oxide-mediated glutathionylation in neuronal function: potential regulation of energy utilization.

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    Yap, Li-Peng; Garcia, Jerome V; Han, Derick S; Cadenas, Enrique

    2010-04-28

    Excessive generation of nitric oxide radical (NO*) in neuroinflammation, excitotoxicity and during age-related neurodegenerative disorders entails the localized and concerted increase in nitric oxide synthase(s) expression in glial cells and neurons. The aim of the present study was to assess the biological significance of the impact of NO* on the cell's thiol status with emphasis on S-glutathionylation of targeted proteins. Exposure of primary cortical neurons or astrocytes to increasing flow rates of NO* (0.061-0.25 microM/s) resulted in the following. (i) A decrease in GSH (glutathione) in neurons accompanied by formation of GSNO (S-nitrosoglutathione) and GSSG (glutathione disulfide); neurons were far more sensitive to NO* exposure than astrocytes. (ii) A dose-dependent oxidation of the cellular redox status: the neuron's redox potential increased approximately 42 mV and that of astrocytes approximately 23 mV. A good correlation was observed between cell viability and the cellular redox potential. The higher susceptibility of neurons to NO* can be partly explained by a reduced capacity to recover GSH through lower activities of GSNO and GSSG reductases. (iii) S-glutathionylation of a small subset of proteins, among them GAPDH (glyceraldehyde-3-phosphate dehydrogenase), the S-glutathionylation of which resulted in inhibition of enzyme activity. The quantitative analyses of changes in the cell's thiol potential upon NO* exposure and their consequences for S-glutathionylation are discussed in terms of the distinct redox environment of astrocytes and neurons.

  18. Nitric oxide mediates alginate oligosaccharides-induced root development in wheat (Triticum aestivum L.).

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    Zhang, Yunhong; Liu, Hang; Yin, Heng; Wang, Wenxia; Zhao, Xiaoming; Du, Yuguang

    2013-10-01

    Alginate oligosaccharides (AOS), which are marine oligosaccharides, are involved in regulating plant root growth, but the promotion mechanism for AOS remains unclear. Here, AOS (10-80 mg L(-1)) were found to induce the generation of nitric oxide (NO) in the root system of wheat (Triticum aestivum L.), which promoted the formation and elongation of wheat roots in a dose-dependent manner. NO inhibitors suggested that nitrate reductase (NR), rather than nitric oxide synthase (NOS), was essential for AOS-induced root development. Further studies confirmed that AOS-induced NO generation in wheat roots by up-regulating the gene expression and enzyme activity of NR at the post-transcriptional level. The anatomy and RT-PCR results showed that AOS accelerated the division and growth of stele cells, leading to an increase in the ratio of stele area to root transverse area. This could be inhibited by the NR inhibitor, sodium tungstate, which indicated that NO catalyzed by the NR was involved in AOS regulation of root development. Taken together, in the early stage of AOS-induced root development, NO generation was a novel mechanism by which AOS regulated plant growth. The results also showed that this marine resource could be widely used for crop development.

  19. Nitric oxide mediates the survival action of IGF-1 and insulin in pancreatic beta cells.

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    Cahuana, Gladys M; Tejedo, Juan R; Hmadcha, Abdelkrim; Ramírez, Remedios; Cuesta, Antonio L; Soria, Bernat; Martin, Franz; Bedoya, Francisco J

    2008-02-01

    Generation of low levels of nitric oxide (NO) contributes to beta cell survival in vitro. The purpose of this study was to explore the link between NO and the survival pathway triggered by insulin-like growth factor-1 (IGF-1) and insulin in insulin producing RINm5F cells and in pancreatic islets. Results show that exposure of cells to IGF-1/insulin protects against serum deprivation-induced apoptosis. This action is prevented with inhibitors of NO generation, PI3K and Akt. Moreover, transfection with the negative dominant form of the tyrosine kinase c-Src abrogates the effect of IGF-1 and insulin on DNA fragmentation. An increase in the expression level of NOS3 protein and in the enzyme activity is observed following exposure of serum-deprived RINm5F cells to IGF-1 and insulin. Phosphorylation of IRS-1, IRS-2 and to less extent IRS-3 takes place when serum-deprived RINm5F cells and rat pancreatic islets are exposed to either IGF-1, insulin, or diethylenetriamine nitric oxide adduct (DETA/NO). In human islets, IRS-1 and IRS-2 proteins are present and tyrosine phosphorylated upon exposure to IGF-1, insulin and DETA/NO. Both rat and human pancreatic islets undergo DNA fragmentation when cultured in serum-free medium and IGF-1, insulin and DETA/NO protect efficiently from this damage. We then conclude that generation of NO participates in the activation of survival pathways by IGF-1 and insulin in beta cells.

  20. Endothelial Nitric Oxide Mediates Caffeine Antagonism of Alcohol-Induced Cerebral Artery Constriction.

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    Chang, Jennifer; Fedinec, Alexander L; Kuntamallappanavar, Guruprasad; Leffler, Charles W; Bukiya, Anna N; Dopico, Alex M

    2016-01-01

    Despite preventive education, the combined consumption of alcohol and caffeine (particularly from "energy drinks") continues to rise. Physiologic perturbations by separate intake of ethanol and caffeine have been widely documented. However, the biologic actions of the alcohol-caffeine combination and their underlying subcellular mechanisms have been scarcely studied. Using intravital microscopy on a closed-cranial window and isolated, pressurized vessels, we investigated the in vivo and in vitro action of ethanol-caffeine mixtures on cerebral arteries from rats and mice, widely recognized models to address cerebrovascular pathophysiology and pharmacology. Caffeine at concentrations found in human circulation after ingestion of one to two cups of coffee (10 µM) antagonized the endothelium-independent constriction of cerebral arteries evoked by ethanol concentrations found in blood during moderate-heavy alcohol intoxication (40-70 mM). Caffeine antagonism against alcohol was similar whether evaluated in vivo or in vitro, suggesting independence of systemic factors and drug metabolism, but required a functional endothelium. Moreover, caffeine protection against alcohol increased nitric oxide (NO•) levels over those found in the presence of ethanol alone, disappeared upon blocking NO• synthase, and could not be detected in pressurized cerebral arteries from endothelial nitric-oxide synthase knockout (eNOS(-/-)) mice. Finally, incubation of de-endothelialized cerebral arteries with the NO• donor sodium nitroprusside (10 µM) fully restored the protective effect of caffeine. This study demonstrates for the first time that caffeine antagonizes ethanol-induced cerebral artery constriction and identifies endothelial NO• as the critical caffeine effector on smooth muscle targets. Conceivably, situations that perturb endothelial function and/or NO• availability will critically alter caffeine antagonism of alcohol-induced cerebrovascular constriction without

  1. Rat duodenal motility in vitro: Prokinetic effects of DL-homocysteine thiolactone and modulation of nitric oxide mediated inhibition

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    Stojanović Marija

    2013-01-01

    Full Text Available Homocysteine is a significant but modifiable risk factor for vascular diseases. As gastrointestinal smooth musculature is similar to blood vessel muscles, we investigated how elevated homocysteine levels affect nitric oxide-mediated neurotransmission in the gut. There is accumulated evidence that a dysfunction of NO neurons in the myenteric plexus may cause various diseases in the gastrointestinal tract such as achalasia, diabetic gastroparesis and infantile hypertrophic pyloric stenosis. In the present study, we aimed to assess the effects of homocysteine on NO-mediated responses in vitro, and to examine the effects of DL-homocysteine thiolactone on the spontaneous motility of rat duodenum and nitrergic neurotransmission. DL-homocysteine thiolactone concentration of 10 μmol/L leads to the immediate increase in tone, amplitude and frequency of spontaneous movements in isolated rat duodenum. L-NAME (30 μmol/L leads to an increase in basal tone, amplitude and frequency of spontaneous contractions. The relaxations induced by EFS were significantly reduced in duodenal segments incubated in DL-homocysteine thiolactone compared with the control group. EFS-induced relaxations were inhibited by L-NAME in both experimental and control groups. These results suggest that a high level of homocysteine causes an important impairment of non-adrenergic non-cholinergic innervation of the rat duodenum. [Projekat Ministarstva nauke Republike Srbije, br. 175043

  2. Nitric oxide-mediated apoptosis in rat macrophages subjected to Shiga toxin 2 from Escherichia coli.

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    Baronetti, José Luis; Villegas, Natalia Angel; Paraje, María Gabriela; Albesa, Inés

    2011-04-01

    Shiga toxin-producing Escherichia coli are important food-borne pathogens. The main factor conferring virulence on this bacterium is its capacity to secrete Shiga toxins (Stxs), which have been reported to induce apoptosis in several cell types. However, the mechanisms of this apoptosis have not yet been fully elucidated. In addition, Stxs have been shown to stimulate macrophages to produce nitric oxide (NO), a well-known apoptosis inductor.The aim of this study was to investigate the participation of NO in apoptosis of rat peritoneal macrophages induced by culture supernatants or Stx2 from E. coli. Peritoneal macrophages incubated in the presence of E. coli supernatants showed an increase in the amounts of apoptosis and NO production. Furthermore, inhibition of NO synthesis induced by addition of aminoguanidine (AG) was correlated with a reduction in the percentage of apoptotic cells, indicating participation of this metabolite in the apoptotic process. Similarly, treatment of cells with Stx2 induced an increase in NO production and amount of apoptosis, these changes being reversed by addition of AG. In summary, these data show that treatment with E. coli supernatants or Stx2 induces NO-mediated apoptosis of macrophages. © 2011 The Societies and Blackwell Publishing Asia Pty Ltd.

  3. Antioxidant systems are regulated by nitric oxide-mediated post-translational modifications (NO-PTMs

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    Juan Carlos Begara-Morales

    2016-02-01

    Full Text Available Nitric oxide (NO is a biological messenger that orchestrates a plethora of plant functions, mainly through post-translational modifications (PTMs such as S-nitrosylation or tyrosine nitration. In plants, hundreds of proteins have been identified as potential targets of these NO-PTMs under physiological and stress conditions indicating the relevance of NO in plant-signaling mechanisms. Among these NO protein targets, there are different antioxidant enzymes involved in the control of reactive oxygen species (ROS, such as H2O2, which is also a signal molecule. This highlights the close relationship between ROS/NO signaling pathways. The major plant antioxidant enzymes, including catalase, superoxide dismutases (SODs peroxiredoxins (Prx and all the enzymatic components of the ascorbate-glutathione (Asa-GSH cycle, have been shown to be modulated to different degrees by NO-PTMs. This mini-review will update the recent knowledge concerning the interaction of NO with these antioxidant enzymes, with a special focus on the components of the Asa-GSH cycle and their physiological relevance.

  4. Endogenous nitric oxide mediates alleviation of cadmium toxicity induced by calcium in rice seedlings

    Institute of Scientific and Technical Information of China (English)

    Long Zhang; Zhen Chen; Cheng Zhu

    2012-01-01

    The effect of calcium chloride (CaCl2) on rice seedling growth under cadmium chloride (CdCl2) stress,as well as the possible role of endogenous nitric oxide (NO) in this process,was studied.The growth of rice seedlings was seriously inhibited by CdCl2,and the inhibition was significantly mitigated by CaCl2.However,hemoglobin (Hb) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline1-oxyl-3-oxide (cPTIO) weakened the promotion effect of CaCl2.The resuhs of NO fluorescence localization suggest that growth accelerated by CaCl2 might be associated with elevated NO levels.The content of Cd,protein thiols (PBT),and nonprotein thiols (NPT) in cell walls,cell organelles,and soluble fractions,respectively,of rice seedlings decreased considerably in the presence of CaCl2,whereas the content of pectin,hemicellulose 1 (HC1),and hemicellulose 2 (HC2) increased significantly.Elimination of endogenous NO in Cd+Ca treatment could promote the transportation of Cd2+ to cell organelles and soluble fractions and increase the content of NPT and PBT in leaves.In addition,transportation of Cd2+ to cell organelles and soluble fractions was retarded in roots,the content of NPT increased,and the content of PBT decreased.With elimination of endogenous NO in Cd+Ca treatment,the content of pectin,HC 1,and HC2 decreased significantly.Thus,Ca may alleviate Cd toxicity via endogenous NO with variation in the levels of NPT,PBT,and matrix polysaccharides.

  5. Nitric Oxide Mediates Molybdenum-Induced Antioxidant Defense in Wheat under Drought Stress

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    Songwei Wu

    2017-06-01

    Full Text Available Molybdenum (Mo has been reported to alleviate drought stress by enhancing antioxidant defense in plants, but the underlying mechanism remains unclear. Here, we hypothesized that Mo mediates nitric oxide (NO-induced antioxidant defense through Mo-enzymes, particularly by nitrate reductase (NR in wheat under drought stress. The 30-day-old wheat seedlings cultivated in -Mo (0 μM Mo and +Mo (1 μM Mo Hoagland solutions were detached and then pretreated with Mo-enzyme inhibitors, NO scavengers, NO donors or their combinations according to demands of complementary experiment under 10% polyethylene glycol 6000 (PEG-stimulated drought stress (PSD. Mo supplementation increased the activities and transcripts of antioxidant enzymes, decreased H2O2 and MDA contents, and elevated NO production, implying that Mo-induced antioxidant defense may be related to NO signal. Complementary experiment showed that NO production was induced by Mo, while suppressed by Mo-enzyme inhibitors and NO scavengers, but restored by NO donors, suggesting that Mo-induced increase of NO production may be due to the regulation by Mo-enzymes. Further experiment indicated that the increased activities and transcripts of antioxidant enzymes induced by Mo were suppressed by Mo-enzyme inhibitors and NO scavengers, and NO donors could eliminate their suppressing effects. Moreover, Mo application increased NR activity and inhibitors of Mo-enzymes inhibited NR activity in wheat leaves under PSD, suggesting that NR might involve in the regulation of Mo-induced NO production. These results clearly indicate that NO mediates Mo-induced antioxidant defense at least partially through the regulation of NR.

  6. Nitric Oxide-Mediated Maize Root Apex Responses to Nitrate are Regulated by Auxin and Strigolactones

    Directory of Open Access Journals (Sweden)

    Alessandro eManoli

    2016-01-01

    Full Text Available Nitrate (NO3- is a key element for crop production but its levels in agricultural soils are limited. Plants have developed mechanisms to cope with these NO3- fluctuations based on sensing nitrate at the root apex. Particularly, the transition zone (TZ of root apex has been suggested as a signalling-response zone. This study dissects cellular and molecular mechanisms underlying NO3- resupply effects on primary root growth in maize, confirming nitric oxide (NO as a putative modulator. Nitrate restoration induced primary root elongation within the first 2 h, corresponding to a stimulation of cell elongation at the basal border of the TZ. Xyloglucans (XGs immunolocalization together with Brefeldin A applications demonstrated that nitrate resupply induces XG accumulation. This effect was blocked by cPTIO (NO scavenger. Transcriptional analysis of ZmXET1 confirmed the stimulatory effect of nitrate on XGs accumulation in cells of the TZ. Immunolocalization analyses revealed a positive effect of nitrate resupply on auxin and PIN1 accumulation, but a transcriptional regulation of auxin biosynthesis/transport/signalling genes was excluded. Short-term nitrate treatment repressed the transcription of genes involved in strigolactones (SLs biosynthesis and transport, mainly in the TZ. Enhancement of carotenoid cleavage dioxygenases (CCDs transcription in presence of cPTIO indicated endogenous NO as a negative modulator of CCDs activity. Finally, treatment with the SLs-biosynthesis inhibitor (TIS108 restored the root growth in the nitrate-starved seedlings. Present report suggests that the NO-mediated root apex responses to nitrate are accomplished in cells of the TZ via integrative actions of auxin, NO and SLs.

  7. Nitric Oxide-Mediated Maize Root Apex Responses to Nitrate are Regulated by Auxin and Strigolactones.

    Science.gov (United States)

    Manoli, Alessandro; Trevisan, Sara; Voigt, Boris; Yokawa, Ken; Baluška, František; Quaggiotti, Silvia

    2015-01-01

    Nitrate (NO3 (-)) is a key element for crop production but its levels in agricultural soils are limited. Plants have developed mechanisms to cope with these NO3 (-) fluctuations based on sensing nitrate at the root apex. Particularly, the transition zone (TZ) of root apex has been suggested as a signaling-response zone. This study dissects cellular and molecular mechanisms underlying NO3 (-) resupply effects on primary root (PR) growth in maize, confirming nitric oxide (NO) as a putative modulator. Nitrate restoration induced PR elongation within the first 2 h, corresponding to a stimulation of cell elongation at the basal border of the TZ. Xyloglucans (XGs) immunolocalization together with Brefeldin A applications demonstrated that nitrate resupply induces XG accumulation. This effect was blocked by cPTIO (NO scavenger). Transcriptional analysis of ZmXET1 confirmed the stimulatory effect of nitrate on XGs accumulation in cells of the TZ. Immunolocalization analyses revealed a positive effect of nitrate resupply on auxin and PIN1 accumulation, but a transcriptional regulation of auxin biosynthesis/transport/signaling genes was excluded. Short-term nitrate treatment repressed the transcription of genes involved in strigolactones (SLs) biosynthesis and transport, mainly in the TZ. Enhancement of carotenoid cleavage dioxygenases (CCDs) transcription in presence of cPTIO indicated endogenous NO as a negative modulator of CCDs activity. Finally, treatment with the SLs-biosynthesis inhibitor (TIS108) restored the root growth in the nitrate-starved seedlings. Present report suggests that the NO-mediated root apex responses to nitrate are accomplished in cells of the TZ via integrative actions of auxin, NO and SLs.

  8. Nitric Oxide Mediated Transcriptome Profiling Reveals Activation of Multiple Regulatory Pathways in Arabidopsis thaliana.

    Science.gov (United States)

    Hussain, Adil; Mun, Bong-Gyu; Imran, Qari M; Lee, Sang-Uk; Adamu, Teferi A; Shahid, Muhammad; Kim, Kyung-Min; Yun, Byung-Wook

    2016-01-01

    Imbalance between the accumulation and removal of nitric oxide and its derivatives is a challenge faced by all plants at the cellular level, and is especially important under stress conditions. Exposure of plants to various biotic and abiotic stresses causes rapid changes in cellular redox tone potentiated by the rise in reactive nitrogen species that serve as signaling molecules in mediating defensive responses. To understand mechanisms mediated by these signaling molecules, we performed a large-scale analysis of the Arabidopsis transcriptome induced by nitrosative stress. We generated an average of 84 and 91 million reads from three replicates each of control and 1 mM S-nitrosocysteine (CysNO)-infiltrated Arabidopsis leaf samples, respectively. After alignment, more than 95% of all reads successfully mapped to the reference and 32,535 genes and 55,682 transcripts were obtained. CysNO infiltration caused differential expression of 6436 genes (3448 up-regulated and 2988 down-regulated) and 6214 transcripts (3335 up-regulated and 2879 down-regulated) 6 h post-infiltration. These differentially expressed genes were found to be involved in key physiological processes, including plant defense against various biotic and abiotic stresses, hormone signaling, and other developmental processes. After quantile normalization of the FPKM values followed by student's T-test (P pathways were verified using quantitative real-time PCR. This study provides comprehensive information about plant responses to nitrosative stress at transcript level and would prove helpful in understanding and incorporating mechanisms associated with nitrosative stress responses in plants.

  9. Leptin induces nitric oxide-mediated inhibition of lipolysis and glyceroneogenesis in rat white adipose tissue.

    Science.gov (United States)

    Niang, Fatoumata; Benelli, Chantal; Ribière, Catherine; Collinet, Martine; Mehebik-Mojaat, Nadia; Penot, Graziella; Forest, Claude; Jaubert, Anne-Marie

    2011-01-01

    Leptin is secreted by white adipose tissue (WAT) and induces lipolysis and nonesterified fatty acid (NEFA) oxidation. During lipolysis, NEFA efflux is the result of triglyceride breakdown, NEFA oxidation, and re-esterification via glyceroneogenesis. Leptin's effects on glyceroneogenesis remain unexplored. We investigated the effect of a long-term treatment with leptin at a physiological concentration (10 μg/L) on lipolysis and glyceroneogenesis in WAT explants and analyzed the underlying mechanisms. Exposure of rat WAT explants to leptin for 2 h resulted in increased NEFA and glycerol efflux. However, a longer treatment with leptin (18 h) did not affect NEFA release and reduced glycerol output. RT-qPCR showed that leptin significantly downregulated the hormone-sensitive lipase (HSL), cytosolic phosphoenolpyruvate carboxykinase (Pck1), and PPARγ genes. In agreement with its effect on mRNA, leptin also decreased the levels of PEPCK-C and HSL proteins. Glyceroneogenesis, monitored by [1-(14) C] pyruvate incorporation into lipids, was reduced. Because leptin increases nitric oxide (NO) production in adipocytes, we explored the role of NO in the leptin signaling pathway. Pretreatment of explants with the NO synthase inhibitor Nω-nitro-l-arginine methyl ester eliminated the effect of leptin on lipolysis, glyceroneogenesis, and expression of the HSL, Pck1, and PPARγ genes. The NO donor S-nitroso-N-acetyl-DL penicillamine mimicked leptin effects, thus demonstrating the role of NO in these pathways. The inverse time-dependent action of leptin on WAT is consistent with a process that limits NEFA re-esterification and energy storage while reducing glycerol release, thus preventing hypertriglyceridemia.

  10. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

    Science.gov (United States)

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  11. Nitric oxide cycle in mammals and the cyclicity principle.

    Science.gov (United States)

    Reutov, V P

    2002-03-01

    This paper continues a series of reports considering nitric oxide (NO) and its cyclic conversions in mammals. Numerous facts are summarized with the goal of developing a general concept that would allow the statement of the multiple effects of NO on various systems of living organisms in the form of a short and comprehensive law. The current state of biological aspects of NO research is analyzed in term of elucidation of possible role of these studies in the system of biological sciences. The general concept is based on a notion on cyclic conversions of NO and its metabolites. NO cycles in living organisms and nitrogen turnover in the biosphere and also the Bethe nitrogen-carbon cycle in star matter are considered. A hypothesis that the cyclic organization of processes in living organisms and the biosphere reflects the evolution of life is proposed: the development of physiological functions and metabolism are suggested to be closely related to space and evolution of the Earth as a planet of the Solar System.

  12. α2A-adrenoceptors, but not nitric oxide, mediate the peripheral cardiac sympatho-inhibition of moxonidine.

    Science.gov (United States)

    Cobos-Puc, Luis E; Aguayo-Morales, Hilda; Silva-Belmares, Yesenia; González-Zavala, Maria A; Centurión, David

    2016-07-05

    Moxonidine centrally inhibits the sympathetic activity through the I1-imidazoline receptor and nitric oxide. In addition, inhibits the peripheral cardiac sympathetic outflow by α2-adrenoceptors/I1-imidazoline receptors, although the role of α2-adrenoceptor subtypes or nitric oxide in the cardiac sympatho-inhibition induced by moxonidine are unknown. Therefore, the cardiac sympatho-inhibition induced by moxonidine (10μg/kgmin) was evaluated before and after of the treatment with the following antagonists/inhibitor: (1) BRL 44408, (300μg/kg, α2A), imiloxan, (3000μg/kg, α2B), and JP-1302, (300μg/kg, α2C), in animals pretreated with AGN 192403 (3000μg/kg, I1 antagonist); (2) N(ω)-nitro-l-arginine methyl ester (l-NAME; 34, 100, and 340μg/kgmin); and (3) the combinations of the highest dose of l-NAME plus AGN 192403 or BRL 44408. Additionally, the expression of the neuronal (nNOS) and inducible (iNOS) nitric oxide synthase in the stellate ganglion was determined after treatment with moxonidine (i.p. 0.56mg/kg daily, during one week). The cardiac sympatho-inhibition of 10μg/kgmin moxonidine was: (1) unaffected by imiloxan and JP-1302, under pretreatment with AGN 192403, or l-NAME (34, 100 and 340μg/kgmin) given alone; (2) partially antagonized by the combination of 340 μg/kgmin l-NAME plus BRL 44408; and (3) abolished by BRL 44408 under treatment with AGN 192403. Furthermore, moxonidine did not modify the nNOS or iNOS protein expression in the stellate ganglion, the main source of postganglionic sympathetic neurons innervating the heart. In conclusion, our results suggest that the peripheral cardiac sympatho-inhibition induced by moxonidine is mediated by α2A-adrenoceptor subtype but not by nitric oxide.

  13. Nitrated type III collagen as a biological marker of nitric oxide-mediated synovial tissue metabolism in osteoarthritis

    DEFF Research Database (Denmark)

    Richardot, P; Charni-Ben Tabassi, N; Toh, L

    2009-01-01

    OBJECTIVES: Nitric oxide (NO) is a major mediator of joint tissue inflammation and damage in osteoarthritis (OA) and mediates the nitration of tyrosine (Y*) residues in proteins. We investigated the nitration of type III collagen, a major constituent of synovial membrane, in knee OA. METHODS...... in healthy controls and significantly correlated with C-reactive protein values (r=0.40, Pcollagen N-telopeptide is increased in the synovial tissue of patients with knee OA. Measurements of serum IIINys level may be useful for the clinical......: A polyclonal antibody directed against the nitrated QY*DSY*DVKSG sequence from type III collagen N-telopeptide was generated. Synovial tissues from patients with knee OA (n=4) and rheumatoid arthritis (RA, n=4) were analyzed by immunohistochemistry for IIINys. Serum IIINys levels were measured by enzyme...

  14. Ascorbic acid improves brachial artery vasodilation during progressive handgrip exercise in the elderly through a nitric oxide-mediated mechanism.

    Science.gov (United States)

    Trinity, Joel D; Wray, D Walter; Witman, Melissa A H; Layec, Gwenael; Barrett-O'Keefe, Zachary; Ives, Stephen J; Conklin, Jamie D; Reese, Van; Zhao, Jia; Richardson, Russell S

    2016-03-15

    The proposed mechanistic link between the age-related attenuation in vascular function and free radicals is an attractive hypothesis; however, direct evidence of free radical attenuation and a concomitant improvement in vascular function in the elderly is lacking. Therefore, this study sought to test the hypothesis that ascorbic acid (AA), administered intra-arterially during progressive handgrip exercise, improves brachial artery (BA) vasodilation in a nitric oxide (NO)-dependent manner, by mitigating free radical production. BA vasodilation (Doppler ultrasound) and free radical outflow [electron paramagnetic resonance (EPR) spectroscopy] were measured in seven healthy older adults (69 ± 2 yr) during handgrip exercise at 3, 6, 9, and 12 kg (∼13-52% of maximal voluntary contraction) during the control condition and nitric oxide synthase (NOS) inhibition via N(G)-monomethyl-L-arginine (L-NMMA), AA, and coinfusion of l-NMMA + AA. Baseline BA diameter was not altered by any of the treatments, while L-NMMA and L-NMMA + AA diminished baseline BA blood flow and shear rate. AA improved BA dilation compared with control at 9 kg (control: 6.5 ± 2.2%, AA: 10.9 ± 2.5%, P = 0.01) and 12 kg (control: 9.5 ± 2.7%, AA: 15.9 ± 3.7%, P vasodilation compared with control and when combined with AA eliminated the AA-induced improvement in BA vasodilation. Free radical outflow increased with exercise intensity but, interestingly, was not attenuated by AA. Collectively, these results indicate that AA improves BA vasodilation in the elderly during handgrip exercise through an NO-dependent mechanism; however, this improvement appears not to be the direct consequence of attenuated free radical outflow from the forearm.

  15. Medullary ventrolateral nitric oxide mediates the cardiac effect of electroacupuncture at "Neiguan" acupoint on acute myocardial ischemia in rats.

    Science.gov (United States)

    Lu, Juan-Xiu; Zhou, Pei-Hua; Wang, Jin; Li, Xia; Cao, Yin-Xiang; Zhou, Xu; Zhu, Da-Nian

    2004-08-25

    Experiments were performed on male Sprague-Dawley (SD) rats anesthetized with a mixture of urethane and chloralose. A rat model of acute myocardial ischemia (AMI) was made by ligation of the left anterior descending branch of the coronary artery (LAD). After the LAD ligation, the ischemia area of the left ventricular wall became somewhat pale immediately. Under a light microscope, the pathological examination revealed that all the cells were swollen and in red color when the cardiac section was stained with hematoxylin basic fuchsin picric acid (HBFP), which indicated a typical change in the myocardial ischemia. In the AMI model, it was found that cardiac functions were markedly attenuated, such as decreases in the heart rate (HR), mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), maximal rate for left ventricular pressure rising and declining (+/-dp/dt(max)), velocity of contractile element (V(CE)) and total area of cardiac force loop (L(0)), and an increase in the left ventricular end diastolic pressure (LVEDP). In such AMI rats, application of electroacupuncture (EA) at "Neiguan" acupoints (Pe 6) for 20 min could obviously improve the above-mentioned cardiac functions. After microinjection of nitro-L-arginine (L-NNA), an inhibitor of nitric oxide synthase (NOS), was made into the rostral ventrolateral medulla (RVLM), the curative effect of EA on myocardial ischemia was reduced significantly or abolished, while after microinjection of normal saline of the same volume was made into the RVLM, the improving effect of EA remained. These results suggest that the effect of EA on myocardial ischemia is possibly mediated by the nitric oxide (NO) in the RVLM.

  16. The mechanism of the nitric oxide-mediated enhancement of tert-butylhydroperoxide-induced DNA single strand breakage

    Science.gov (United States)

    Guidarelli, Andrea; Clementi, Emilio; Sciorati, Clara; Cantoni, Orazio

    1998-01-01

    Caffeine (Cf) enhances the DNA cleavage induced by tert-butylhydroperoxide (tB-OOH) in U937 cells via a mechanism involving Ca2+-dependent mitochondrial formation of DNA-damaging species (Guidarelli et al., 1997b). Nitric oxide (NO) is not involved in this process since U937 cells do not express the constitutive nitric oxide synthase (cNOS).Treatment with the NO donors S-nitroso-N-acetyl-penicillamine (SNAP, 10 μM), or S-nitrosoglutathione (GSNO, 300 μM), however, potentiated the DNA strand scission induced by 200 μM tB-OOH. The DNA lesions generated by tB-OOH alone, or combined with SNAP, were repaired with superimposable kinetics and were insensitive to anti-oxidants and peroxynitrite scavengers but suppressed by iron chelators.SNAP or GSNO did not cause mitochondrial Ca2+ accumulation but their enhancing effects on the tB-OOH-induced DNA strand scission were prevented by ruthenium red, an inhibitor of the calcium uniporter of mitochondria. Furthermore, the enhancing effects of both SNAP and GSNO were identical to and not additive with those promoted by the Ca2+-mobilizing agents Cf or ATP.The SNAP- or GSNO-mediated enhancement of the tB-OOH-induced DNA cleavage was abolished by the respiratory chain inhibitors rotenone and myxothiazol and was not apparent in respiration-deficient cells.It is concluded that, in cells which do not express the enzyme cNOS, exogenous NO enhances the accumulation of DNA single strand breaks induced by tB-OOH via a mechanism involving inhibition of complex III. PMID:9846647

  17. Oleic acid-dependent modulation of Nitric oxide associated 1 protein levels regulates nitric oxide-mediated defense signaling in Arabidopsis

    Science.gov (United States)

    The conserved cellular metabolites nitric oxide (NO) and oleic acid (18:1) are well-known regulators of disease physiologies in diverse organism. We show that NO production in plants is regulated via 18:1. Reduction in 18:1 levels, via a genetic mutation in the 18:1-synthesizing gene SUPPRESSOR OF S...

  18. Sinorhizobium meliloti Controls Nitric Oxide-Mediated Post-Translational Modification of a Medicago truncatula Nodule Protein.

    Science.gov (United States)

    Blanquet, Pauline; Silva, Liliana; Catrice, Olivier; Bruand, Claude; Carvalho, Helena; Meilhoc, Eliane

    2015-12-01

    Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about the molecular mechanisms responsible for NO effects in the legume-rhizobium interaction. Here, we investigate the contribution of the bacterial NO response to the modulation of a plant protein post-translational modification in nitrogen-fixing nodules. We made use of different bacterial mutants to finely modulate NO levels inside M. truncatula root nodules and to examine the consequence on tyrosine nitration of the plant glutamine synthetase, a protein responsible for assimilation of the ammonia released by nitrogen fixation. Our results reveal that S. meliloti possesses several proteins that limit inactivation of plant enzyme activity via NO-mediated post-translational modifications. This is the first demonstration that rhizobia can impact the course of nitrogen fixation by modulating the activity of a plant protein.

  19. Contribution of radiation-induced, nitric oxide-mediated bystander effect to radiation-induced adaptive response.

    Science.gov (United States)

    Matsumoto, H.; Ohnishi, T.

    There has been a recent upsurge of interest in radiation-induced adaptive response and bystander effect which are specific modes in stress response to low-dose low-dose rate radiation Recently we found that the accumulation of inducible nitric oxide NO synthase iNOS in wt p53 cells was induced by chronic irradiation with gamma rays followed by acute irradiation with X-rays but not by each one resulting in an increase in nitrite concentrations of medium It is suggested that the accumulation of iNOS may be due to the depression of acute irradiation-induced p53 functions by pre-chronic irradiation In addition we found that the radiosensitivity of wt p53 cells against acute irradiation with X-rays was reduced after chronic irradiation with gamma rays This reduction of radiosensitivity of wt p53 cells was nearly completely suppressed by the addition of NO scavenger carboxy-PTIO to the medium This reduction of radiosensitivity of wt p53 cells is just radiation-induced adaptive response suggesting that NO-mediated bystander effect may considerably contribute to adaptive response induced by radiation

  20. Nitric oxide mediates effects of acute, not chronic, naltrexone on LPS-induced hepatic encephalopathy in cirrhotic rats.

    Science.gov (United States)

    Ghiassy, Bentolhoda; Rahimi, Nastaran; Javadi-Paydar, Mehrak; Gharedaghi, Mohammad Hadi; Norouzi-Javidan, Abbas; Dehpour, Ahmad R

    2017-01-01

    Recent studies suggest endogenous opioids and nitric oxide (NO) are involved in the pathophysiology of hepatic encephalopathy (HE). In this study, the interaction between the opioid receptor antagonist and NO was investigated on lipopolysaccharide (LPS)-induced HE in cirrhotic rats. Male rats were divided in the sham- and bile duct ligation (BDL)-operated groups. Animals were treated with saline; naltrexone (10 mg/kg, i.p.); or L-NAME (3 mg/kg, i.p.), alone or in combination with naltrexone. To induce HE, LPS (1 mg/kg, i.p.) was injected 1 h after the final drug treatment. HE scoring, hepatic histology, and plasma NO metabolites levels and mortality rate were recorded. Deteriorated level of consciousness and mortality after LPS administration significantly ameliorated following both acute and chronic treatment with naltrexone in cirrhotic rats. However, acute and chronic administration of L-NAME did not change HE scores in cirrhotic rats. The effects of acute but not chronic treatment of naltrexone on HE parameters were reversed by L-NAME. Plasma NOx concentrations elevated in BDL rats, which were decreased after acute and chronic treatment by naltrexone or L-NAME, significantly. We suggest both acute and chronic treatment with naltrexone improved LPS-induced HE. But, only acute treatment with naltrexone may affect through NO pathway.

  1. Salt stress reduces root meristem size by nitric oxide-mediated modulation of auxin accumulation and signaling in Arabidopsis.

    Science.gov (United States)

    Liu, Wen; Li, Rong-Jun; Han, Tong-Tong; Cai, Wei; Fu, Zheng-Wei; Lu, Ying-Tang

    2015-05-01

    The development of the plant root system is highly plastic, which allows the plant to adapt to various environmental stresses. Salt stress inhibits root elongation by reducing the size of the root meristem. However, the mechanism underlying this process remains unclear. In this study, we explored whether and how auxin and nitric oxide (NO) are involved in salt-mediated inhibition of root meristem growth in Arabidopsis (Arabidopsis thaliana) using physiological, pharmacological, and genetic approaches. We found that salt stress significantly reduced root meristem size by down-regulating the expression of PINFORMED (PIN) genes, thereby reducing auxin levels. In addition, salt stress promoted AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) stabilization, which repressed auxin signaling during this process. Furthermore, salt stress stimulated NO accumulation, whereas blocking NO production with the inhibitor N(ω)-nitro-l-arginine-methylester compromised the salt-mediated reduction of root meristem size, PIN down-regulation, and stabilization of AXR3/IAA17, indicating that NO is involved in salt-mediated inhibition of root meristem growth. Taken together, these findings suggest that salt stress inhibits root meristem growth by repressing PIN expression (thereby reducing auxin levels) and stabilizing IAA17 (thereby repressing auxin signaling) via increasing NO levels. © 2015 American Society of Plant Biologists. All Rights Reserved.

  2. Lichen metabolites prevent UV light and nitric oxide-mediated plasmid DNA damage and induce apoptosis in human melanoma cells.

    Science.gov (United States)

    Russo, A; Piovano, M; Lombardo, L; Garbarino, J; Cardile, V

    2008-09-26

    In humans both UV-A and UV-B can cause gene mutations and suppress immunity, which leads to skin cancer, including melanoma. Inhibition of reactive oxygen species (ROS) and reactive nitrogen species (RNS) appears particularly promising as ROS and RNS production by both UV-A and UV-B contributes to inflammation, immunosuppression, gene mutation and carcinogenesis. We evaluated the effect of two lichen compounds, sphaerophorin (depside) and pannarin (depsidone) on pBR322 DNA cleavage induced by hydroxyl radicals (()OH), and by nitric oxide (NO), and their superoxide anion (O(2)(-)) scavenging capacity. In addition, we investigated the growth inhibitory activity of these compounds against human melanoma cells (M14 cell line). Sphaerophorin and pannarin showed a protective effect on plasmid DNA and exhibited a superoxide dismutase like effect. The data obtained in cell culture show that these lichen metabolites inhibit the growth of melanoma cells, inducing an apoptotic cell death, demonstrated by the fragmentation of genomic DNA (COMET and TUNEL Assays) and by a significant increase of caspase-3 activity, and correlated, at least in part, to the increase of ROS generation, These results confirm the promising biological properties of sphaerophorin and pannarin and encourage further investigations on their molecular mechanisms.

  3. Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings.

    Science.gov (United States)

    Bharti, Niharika; Bhatla, Satish C

    2015-01-01

    Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca(2+)]cyt in the apical region and differentiating zones of LR, indicating a critical role of [Ca(2+)] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development.

  4. Enhanced nitric oxide-mediated autophagy contributes to the hepatoprotective effects of ischemic preconditioning during ischemia and reperfusion.

    Science.gov (United States)

    Shin, Jun-Kyu; Kang, Jung-Woo; Lee, Sun-Mee

    2016-08-31

    Ischemic preconditioning (IPC) protects against liver ischemia/reperfusion (I/R) injury. Autophagy is an essential cytoprotective system that is rapidly activated by multiple stressors. Nitric oxide (NO) acts as an inducer of IPC. We examined the impact of autophagy in liver IPC and its regulation by NO. Male C57BL/6 mice were subjected to 60 min of hepatic ischemia followed by 6 h of reperfusion. IPC was achieved for 10 min of ischemia followed by 10 min of reperfusion prior to sustained ischemia. N(ω)-Nitro-l-arginine methyl ester (L-NAME, 15 mg/kg, i.v., all NOS inhibitor) and aminoguanidine (AG, 10 mg/kg, i.v., iNOS inhibitor) were injected 10 min before IPC. SB203580 (10 mg/kg, i.p., p38 inhibitor) was injected 30 min before IPC. I/R increased serum alanine aminotransferase activity. IPC attenuated this increase, which was abolished by L-NAME, but not AG. Microtubule-associated protein-1 light chain 3-II levels increased and p62 protein levels decreased after I/R; these changes were augmented by IPC and abolished by L-NAME. I/R increased liver protein expression of autophagy-related protein (Atg)12-Atg5 complex and lysosome-associated membrane protein-2. IPC augmented the expression of these proteins, which were abolished by L-NAME, but not AG. IPC also augmented the level of phosphorylated p38 MAPK induced by I/R and this phosphorylation was abolished by L-NAME. Our findings suggest that IPC-mediated NO protects against I/R-induced liver injury by enhancing autophagic flux.

  5. Role of metabolic environment on nitric oxide mediated inhibition of neointimal hyperplasia in type 1 and type 2 diabetes.

    Science.gov (United States)

    Rodriguez, Monica P; Emond, Zachary M; Wang, Zheng; Martinez, Janet; Jiang, Qun; Kibbe, Melina R

    2014-01-30

    Nitric oxide (NO) is well known to inhibit neointimal hyperplasia following arterial injury. Previously, we reported that NO was more effective at inhibiting neointimal hyperplasia in a type 2 diabetic environment than control. We also found that NO was ineffective in an uncontrolled type 1 diabetic environment; however, insulin restored the efficacy of NO. Thus, the goal of this study was to more closely evaluate the effect of insulin and glucose on the efficacy of NO at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments using different doses of insulin as well as pioglitazone. Type 1 diabetes was induced in male lean Zucker (LZ) rats with streptozotocin (60 mg/kg IP). Groups included control, moderate glucose control, and tight glucose control. Zucker diabetic fatty (ZDF) rats fed Purina 5008 chow were used as a type 2 diabetic model. Groups included no therapy, insulin therapy, or pioglitazone therapy. After 4 weeks of maintaining group assignments, the carotid artery injury model was performed. Treatment groups included: control, injury and injury plus NO. 2 weeks following arterial injury, in the type 1 diabetic rats, NO most effectively reduced the neointimal area in the moderate and tightly controlled groups (81% and 88% vs. 33%, respectively, p=0.01). In type 2 diabetic rats, the metabolic environment had no impact on the efficacy of NO (81-82% reduction for all groups). Thus, in this study, we show NO is effective at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments. A greater understanding of how the metabolic environment may impact the efficacy of NO may lead to the development of more effective NO-based therapies for patients with diabetes.

  6. Role of Metabolic Environment on Nitric Oxide Mediated Inhibition of Neointimal Hyperplasia in Type 1 and Type 2 Diabetes

    Science.gov (United States)

    Wang, Zheng; Martinez, Janet; Jiang, Qun; Kibbe, Melina R.

    2014-01-01

    Nitric oxide (NO) is well known to inhibit neointimal hyperplasia following arterial injury. Previously, we reported that NO was more effective at inhibiting neointimal hyperplasia in a type 2 diabetic environment than control. We also found that NO was ineffective in an uncontrolled type 1 diabetic environment; however, insulin restored the efficacy of NO. Thus, the goal of this study was to more closely evaluate the effect of insulin and glucose on the efficacy of NO at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments using different doses of insulin as well as pioglitazone. Type 1 diabetes was induced in male Lean Zucker (LZ) rats with streptozotocin (60mg/kg IP). Groups included control, moderate glucose control, and tight glucose control. Zucker Diabetic Fatty (ZDF) rats fed Purina 5008 chow were used as a type 2 diabetic model. Groups included no therapy, insulin therapy, or pioglitazone therapy. After 4 weeks of maintaining group assignments, the carotid artery injury model was performed. Treatment groups included: control, injury, and injury plus NO. 2 weeks following arterial injury, in the type 1 diabetic rats, NO most effectively reduced the neointimal area in the moderate and tightly controlled groups (81% and 88% vs. 33%, respectively, p=0.01). In type 2 diabetic rats, the metabolic environment had no impact on the efficacy of NO (81%–82% reduction for all groups). Thus, in this study, we show NO is effective at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments. A greater understanding of how the metabolic environment may impact the efficacy of NO may lead to the development of more effective NO-based therapies for patients with diabetes. PMID:24333562

  7. Inhibition of root meristem growth by cadmium involves nitric oxide-mediated repression of auxin accumulation and signalling in Arabidopsis.

    Science.gov (United States)

    Yuan, Hong-Mei; Huang, Xi

    2016-01-01

    The root is the first plant organ to get in contact with the toxin cadmium (Cd), which is a widespread soil contaminant. Cd inhibits the growth of the primary root, but the mechanisms underlying this inhibition remain elusive. In this study, we used physiological, pharmacological and genetic approaches to investigate the roles of nitric oxide (NO) and auxin in Cd-mediated inhibition of Arabidopsis thaliana root meristem growth. Our study demonstrated that in the first 12 h of exposure, Cd inhibits primary root elongation through a decrease in the sizes of both the elongation and meristematic zones. Following Cd exposure, a decrease in auxin levels is associated with reduced PIN1/3/7 protein accumulation, but not with reduced PIN1/3/7 transcript levels. Additionally, Cd stabilized AXR3/IAA17 protein to repress auxin signalling in this Cd-mediated process. Furthermore, decreasing Cd-induced NO accumulation with either NO-specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) or NO synthase inhibitor N(ω) -nitro-l-Arg-methylester (l-NAME) compromised the Cd-mediated inhibition of root meristem development, reduction in auxin and PIN1/3/7 accumulation, as well as stabilization of AXR3/IAA17, indicating that NO participates in Cd-mediated inhibition of root meristem growth. Taken together, our data suggest that Cd inhibits root meristem growth by NO-mediated repression of auxin accumulation and signalling in Arabidopsis. © 2015 John Wiley & Sons Ltd.

  8. Caveolin-1 is important for nitric oxide-mediated angiogenesis in fibrin gels with human umbilical vein endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Yi-ming PAN; Yong-zhong YAO; Zhang-hua ZHU; Xi-tai SUN; Yu-dong QIU; Yi-tao DING

    2006-01-01

    Aim: The role of caveolin-l (Cav-1) in angiogenesis remains poorly understood. The endothelial nitric oxide (NO) synthase (eNOS), a caveolin-interacting protein, was demonstrated to play a predominant role in vascular endothelial growth factor (VEGF) -induced angiogenesis. The purpose of our study was to examine the role of Cav-1 and the eNOS complex in NO-mediated angiogenesis. Methods: Human umbilical vein endothelial cells (HUVEC) were isolated and cultured in 3-D fibrin gels to form capillary-like tubules by VEGF stimulation. The expression of Cav-1 and eNOS was detected by semiquantitative RT-PCR. The HUVEC were treated with antisense oligonucleotides to downregulate Cav-1 expression. Both transduced and non-infected HUVEC were cultured in fibrin gels in the presence or absence of VEGF (20 ng/mL) and NG-nitro-L-arginine methyl ester (L-NAME; 5 mmol/L). NO was measured using a NO assay kit and capillary-like tubules were quantified by tubule formation index using the Image J program. Results: RT-PCR analysis revealed that Cav-1 levels steadily increased in a time-dependent manner and reached their maximum after 5 d of incubation, but there were no obvious changes in eNOS mRNA expression in response to VEGF in the fibrin gel model. VEGF (20 ng/mL) can promote NO production and the formation of capillary-like tubules, and this promoting effect of VEGF was blocked by the addition of L-NAME (5 mmol/L). When transduced HUVEC with the antisense Cav-1 oligonucleotides were plated in the fibrin gels, the capillary-like tubules were significantly fewer than those of the non-infected cells. The capillary-like tubules formation and NO production of transduced HUVEC with the antisense Cav-1 oligonucleotides cultured in fibrin gels showed no responses to the addition of VEGF (20 ng/mL) and L-NAME (5.0 mmol/L). Conclusion: NO was a critical angiogenic mediator in this model. Cav-1 was essential for NO-mediated angiogenesis and may be an important target of anti

  9. Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways

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    Mohammad Hafiz Abdul Rahim

    2016-01-01

    Full Text Available The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract of Clinacanthus nutans (Acanthaceae leaves (MECN using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA, 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg was determined using the acetic acid-induced abdominal constriction (ACT, formalin-induced paw licking (FT, and hot plate tests (HPT. The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP systems was also investigated. The results showed that MECN produced a significant (p500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist but was partially reversed by L-arginine (L-arg; a nitric oxide [NO] precursor, Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; an NO synthase inhibitor, or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor enhanced the extract’s antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems.

  10. Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways.

    Science.gov (United States)

    Abdul Rahim, Mohammad Hafiz; Zakaria, Zainul Amiruddin; Mohd Sani, Mohd Hijaz; Omar, Maizatul Hasyima; Yakob, Yusnita; Cheema, Manraj Singh; Ching, Siew Mooi; Ahmad, Zuraini; Abdul Kadir, Arifah

    2016-01-01

    The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract of Clinacanthus nutans (Acanthaceae) leaves (MECN) using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA), 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg) was determined using the acetic acid-induced abdominal constriction (ACT), formalin-induced paw licking (FT), and hot plate tests (HPT). The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) systems was also investigated. The results showed that MECN produced a significant (p 500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist) but was partially reversed by l-arginine (l-arg; a nitric oxide [NO] precursor), Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; an NO synthase inhibitor), or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor) enhanced the extract's antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems.

  11. Nitric oxide mediates the fungal elicitor-induced Taxol biosynthesis of Taxus chinensis suspension cells through the reactive oxygen species-dependent and-independent signal pathways

    Institute of Scientific and Technical Information of China (English)

    XU Maojun; DONG Jufang

    2006-01-01

    Nitric oxide and reactive oxygen species are two important signal molecules that play key roles in plant defense responses. Nitric oxide generation and oxidative burst and accumulation of reactive oxygen species are the early reactions of Taxus chinensis suspension cells to fungal elicitor prepared from the cell walls of Penicillium citrinum. In order to investigate the relationship and/or interactions of nitric oxide and reactive oxygen species in the elicitor-induced Taxol biosynthesis of T. chinensis suspension cells, we treated the cells with nitric oxide specific scavenger 2-4-carboxyphenyl-4,4,5,5-tetra- methylimidazoline-1-oxyl-3-oxide (cPITO), nitric oxide synthase inhibitor S,S(-1,3-phenylene-bis(1,2-eth- anediyl)-bis-isothiourea (PBITU), membrane NAD(P) H oxidase inhibitor diphenylene iodonium (DPI), superoxide dismutases (SOD) and catalase. The results show that pretreatment of T. chinensis cells with cPITO and DPI inhibited not only the elicitor-induced nitric oxide biosynthesis and oxidative burst, but also the elicitor-induced Taxol production, suggesting that both nitric oxide and reactive oxygen species are involved in elicitor-induced Taxol biosynthesis. Furthermore, pretreatment of the cells with cPITO and PBITU suppressed the elicitor-induced oxidative burst, indicating that the oxidative burst might be dependent on NO. Application of nitric oxide via its donor sodium nitroprusside (SNP) triggered Taxol biosynthesis of T. chinensis cells. The nitric oxide-induced Taxol production was suppressed by DPI, showing that the oxidative burst is involved in NO-triggered Taxol biosynthesis. However, nitric oxide and the fungal elicitor induced Taxol biosynthesis even though the accumulation of reactive oxygen species wass completely abolished in T. chinensis cells. Our data show that nitric oxide may mediate the elicitor-induced Taxol biosynthesis of T. chinensis suspension cells through both reactive oxygen species-dependent and -independent signal

  12. Nitric oxide mediates aortic disease in mice deficient in the metalloprotease Adamts1 and in a mouse model of Marfan syndrome.

    Science.gov (United States)

    Oller, Jorge; Méndez-Barbero, Nerea; Ruiz, E Josue; Villahoz, Silvia; Renard, Marjolijn; Canelas, Lizet I; Briones, Ana M; Alberca, Rut; Lozano-Vidal, Noelia; Hurlé, María A; Milewicz, Dianna; Evangelista, Arturo; Salaices, Mercedes; Nistal, J Francisco; Jiménez-Borreguero, Luis Jesús; De Backer, Julie; Campanero, Miguel R; Redondo, Juan Miguel

    2017-02-01

    Heritable thoracic aortic aneurysms and dissections (TAAD), including Marfan syndrome (MFS), currently lack a cure, and causative mutations have been identified for only a fraction of affected families. Here we identify the metalloproteinase ADAMTS1 and inducible nitric oxide synthase (NOS2) as therapeutic targets in individuals with TAAD. We show that Adamts1 is a major mediator of vascular homeostasis, given that genetic haploinsufficiency of Adamts1 in mice causes TAAD similar to MFS. Aortic nitric oxide and Nos2 levels were higher in Adamts1-deficient mice and in a mouse model of MFS (hereafter referred to as MFS mice), and Nos2 inactivation protected both types of mice from aortic pathology. Pharmacological inhibition of Nos2 rapidly reversed aortic dilation and medial degeneration in young Adamts1-deficient mice and in young or old MFS mice. Patients with MFS showed elevated NOS2 and decreased ADAMTS1 protein levels in the aorta. These findings uncover a possible causative role for the ADAMTS1-NOS2 axis in human TAAD and warrant evaluation of NOS2 inhibitors for therapy.

  13. Mangiferin Prevents Guinea Pig Tracheal Contraction via Activation of the Nitric Oxide-Cyclic GMP Pathway

    Science.gov (United States)

    Vieira, Aline B.; Coelho, Luciana P.; Insuela, Daniella B. R.; Carvalho, Vinicius F.; dos Santos, Marcelo H.; Silva, Patricia MR.; Martins, Marco A.

    2013-01-01

    Previous studies have described the antispasmodic effect of mangiferin, a natural glucoside xanthone (2-C-β-Dgluco-pyranosyl-1,3,6,7-tetrahydroxyxanthone) that is present in mango trees and other plants, but its mechanism of action remains unknown. The aim of this study was to examine the potential contribution of the nitric oxide-cyclic GMP pathway to the antispasmodic effect of mangiferin on isolated tracheal rings preparations. The functional effect of mangiferin on allergic and non-allergic contraction of guinea pig tracheal rings was assessed in conventional organ baths. Cultured tracheal rings were exposed to mangiferin or vehicle, and nitric oxide synthase (NOS) 3 and cyclic GMP (cGMP) levels were quantified using western blotting and enzyme immunoassays, respectively. Mangiferin (0.1–10 µM) inhibited tracheal contractions induced by distinct stimuli, such as allergen, histamine, 5-hydroxytryptamine or carbachol, in a concentration-dependent manner. Mangiferin also caused marked relaxation of tracheal rings that were precontracted by carbachol, suggesting that it has both anti-contraction and relaxant properties that are prevented by removing the epithelium. The effect of mangiferin was inhibited by the nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME) (100 µM), and the soluble guanylate cyclase inhibitor, 1H-[1], [2], [4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 µM), but not the adenylate cyclase inhibitor, 9-(tetrahydro-2-furyl)adenine (SQ22536) (100 µM). The antispasmodic effect of mangiferin was also sensitive to K+ channel blockers, such as tetraethylammonium (TEA), glibenclamide and apamin. Furthermore, mangiferin inhibited Ca2+-induced contractions in K+ (60 mM)-depolarised tracheal rings preparations. In addition, mangiferin increased NOS3 protein levels and cGMP intracellular levels in cultured tracheal rings. Finally, mangiferin-induced increase in cGMP levels was abrogated by co-incubation with either ODQ or L

  14. Mangiferin prevents guinea pig tracheal contraction via activation of the nitric oxide-cyclic GMP pathway.

    Directory of Open Access Journals (Sweden)

    Aline B Vieira

    Full Text Available Previous studies have described the antispasmodic effect of mangiferin, a natural glucoside xanthone (2-C-β-Dgluco-pyranosyl-1,3,6,7-tetrahydroxyxanthone that is present in mango trees and other plants, but its mechanism of action remains unknown. The aim of this study was to examine the potential contribution of the nitric oxide-cyclic GMP pathway to the antispasmodic effect of mangiferin on isolated tracheal rings preparations. The functional effect of mangiferin on allergic and non-allergic contraction of guinea pig tracheal rings was assessed in conventional organ baths. Cultured tracheal rings were exposed to mangiferin or vehicle, and nitric oxide synthase (NOS 3 and cyclic GMP (cGMP levels were quantified using western blotting and enzyme immunoassays, respectively. Mangiferin (0.1-10 µM inhibited tracheal contractions induced by distinct stimuli, such as allergen, histamine, 5-hydroxytryptamine or carbachol, in a concentration-dependent manner. Mangiferin also caused marked relaxation of tracheal rings that were precontracted by carbachol, suggesting that it has both anti-contraction and relaxant properties that are prevented by removing the epithelium. The effect of mangiferin was inhibited by the nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME (100 µM, and the soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ (10 µM, but not the adenylate cyclase inhibitor, 9-(tetrahydro-2-furyladenine (SQ22536 (100 µM. The antispasmodic effect of mangiferin was also sensitive to K⁺ channel blockers, such as tetraethylammonium (TEA, glibenclamide and apamin. Furthermore, mangiferin inhibited Ca²⁺-induced contractions in K⁺ (60 mM-depolarised tracheal rings preparations. In addition, mangiferin increased NOS3 protein levels and cGMP intracellular levels in cultured tracheal rings. Finally, mangiferin-induced increase in cGMP levels was abrogated by co-incubation with either ODQ

  15. Impaired functions of neural stem cells by abnormal nitric oxide-mediated signaling in an in vitro model of Niemann-Pick type C disease

    Institute of Scientific and Technical Information of China (English)

    Sun-Jung Kim; Myung-Sin Lim; Soo-Kyung Kang; Yong-Soon Lee; Kyung-Sun Kang

    2008-01-01

    Nitric oxide (NO) has been implicated in the promotion of neurodegeneration.However,little is known about the relationship between NO and the self-renewal or differentiation capacity of neural stem cells (NSCs) in neurodegenerative disease.In this study,we investigated the effect of NO on self-renewal of NSCs in an animal model for Niemann-Pick type C (NPC) disease.We found that NO production was significantly increased in NSCs from NPC1-deficient mice (NPC1-/-),which showed reduced NSC self-renewal.The number of nestin-positive cells and the size of neurospheres were both significantly decreased.The expression of NO synthase (NOS) was increased in neurospheres derived from the brain of NPC1-/- mice in comparison to wild-type neurospheres.NO-mediated activation of glycogen synthase kinase-3β(GSK3β) and caspase-3 was also observed in NSCs from NPC1-/- mice.The self-renewal ability of NSCs from NPC1-/- mice was restored by an NOS inhibitor,L-NAME,which resulted in the inhibition of GSK3β and caspase-3.In addition,the differentiation ability of NSCs was partially restored and the number of Fluoro-Jade C-positive degenerating neurons was reduced.These data suggest that overproduction of NO in NPC disease impaired the self-renewal of NSCs.Control of NO production may be key for the treatment of NPC disease.

  16. Salt Stress Reduces Root Meristem Size by Nitric Oxide-Mediated Modulation of Auxin Accumulation and Signaling in Arabidopsis1[OPEN

    Science.gov (United States)

    Liu, Wen; Li, Rong-Jun; Han, Tong-Tong; Cai, Wei; Fu, Zheng-Wei

    2015-01-01

    The development of the plant root system is highly plastic, which allows the plant to adapt to various environmental stresses. Salt stress inhibits root elongation by reducing the size of the root meristem. However, the mechanism underlying this process remains unclear. In this study, we explored whether and how auxin and nitric oxide (NO) are involved in salt-mediated inhibition of root meristem growth in Arabidopsis (Arabidopsis thaliana) using physiological, pharmacological, and genetic approaches. We found that salt stress significantly reduced root meristem size by down-regulating the expression of PINFORMED (PIN) genes, thereby reducing auxin levels. In addition, salt stress promoted AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) stabilization, which repressed auxin signaling during this process. Furthermore, salt stress stimulated NO accumulation, whereas blocking NO production with the inhibitor Nω-nitro-l-arginine-methylester compromised the salt-mediated reduction of root meristem size, PIN down-regulation, and stabilization of AXR3/IAA17, indicating that NO is involved in salt-mediated inhibition of root meristem growth. Taken together, these findings suggest that salt stress inhibits root meristem growth by repressing PIN expression (thereby reducing auxin levels) and stabilizing IAA17 (thereby repressing auxin signaling) via increasing NO levels. PMID:25818700

  17. High-affinity uptake of kynurenine and nitric oxide-mediated inhibition of indoleamine 2,3-dioxygenase in bone marrow-derived myeloid dendritic cells.

    Science.gov (United States)

    Hara, Toshiaki; Ogasawara, Nanako; Akimoto, Hidetoshi; Takikawa, Osamu; Hiramatsu, Rie; Kawabe, Tsutomu; Isobe, Ken-Ichi; Nagase, Fumihiko

    2008-02-15

    Indoleamine 2,3-dioxygenase (IDO)-initiated tryptophan metabolism along the kynurenine (Kyn) pathway in some dendritic cells (DC) such as plasmacytoid DC (pDC) regulates T-cell responses. It is unclear whether bone marrow-derived myeloid DC (BMDC) express functional IDO. The IDO expression was examined in CD11c(+)CD11b(+) BMDC differentiated from mouse bone marrow cells using GM-CSF. CpG oligodeoxynucleotides (CpG) induced the expression of IDO protein with the production of nitric oxide (NO) in BMDC in cultures for 24h. In the enzyme assay using cellular extracts of BMDC, the IDO activity of BMDC stimulated with CpG was enhanced by the addition of a NO synthase (NOS) inhibitor, suggesting that IDO activity was suppressed by NO production. On the other hand, the concentration of Kyn in the culture supernatant of BMDC was not increased by stimulation with CpG. Exogenously added Kyn was taken up by BMDC independently of CpG stimulation and NO production, and the uptake of Kyn was inhibited by a transport system L-specific inhibitor or high concentrations of tryptophan. The uptake of tryptophan by BMDC was markedly lower than that of Kyn. In conclusion, IDO activity in BMDC is down-regulated by NO production, whereas BMDC strongly take up exogenous Kyn.

  18. Nitric oxide-mediated vascular function in sepsis using passive leg movement as a novel assessment: a cross-sectional study.

    Science.gov (United States)

    Nelson, Ashley D; Rossman, Matthew J; Witman, Melissa A; Barrett-O'Keefe, Zachary; Groot, H Jonathan; Garten, Ryan S; Richardson, Russell S

    2016-05-01

    Post-cuff occlusion flow-mediated dilation (FMD) is a proposed indicator of nitric oxide (NO) bioavailability and vascular function. FMD is reduced in patients with sepsis and may be a marker of end organ damage and mortality. However, FMD likely does not solely reflect NO-mediated vasodilation, is technically challenging, and often demonstrates poor reproducibility. In contrast, passive leg movement (PLM), a novel methodology to assess vascular function, yields a hyperemic response that is predominately NO-dependent, reproducible, and easily measured. This study evaluated PLM as an approach to assess NO-mediated vascular function in patients with sepsis. We hypothesized that PLM-induced hyperemia, quantified by the increase in leg blood flow (LBF), would be attenuated in sepsis. In a cross-sectional study, 17 subjects in severe sepsis or septic shock were compared with 16 matched healthy controls. Doppler ultrasound was used to assess brachial artery FMD and the hyperemic response to PLM in the femoral artery. FMD was attenuated in septic compared with control subjects (1.1 ± 1.7% vs. 6.8 ± 1.3%; values are means ± SD). In terms of PLM, baseline LBF (196 ± 33 ml/min vs. 328 ± 20 ml/min), peak change in LBF from baseline (133 ± 28 ml/min vs. 483 ± 86 ml/min), and the LBF area under the curve (16 ± 8.3 vs. 143 ± 33) were all significantly attenuated in septic subjects. Vascular function, as assessed by both FMD and PLM, is attenuated in septic subjects compared with controls. These data support the concept that NO bioavailability is attenuated in septic subjects, and PLM appears to be a novel and feasible approach to assess NO-mediated vascular function in sepsis.

  19. Boldo prevents UV light and nitric oxide-mediated plasmid DNA damage and reduces the expression of Hsp70 protein in melanoma cancer cells.

    Science.gov (United States)

    Russo, Alessandra; Cardile, Venera; Caggia, Silvia; Gunther, Germán; Troncoso, Nicolas; Garbarino, Juan

    2011-09-01

    This study was designed to investigate the potential protective effect of a methanolic extract of Peumus boldus leaves on UV light and nitric oxide (NO)-mediated DNA damage. In addition, we investigated the growth inhibitory activity of this natural product against human melanoma cells (M14). Boldine, catechin, quercetin and rutin were identified using a HPLC method. The extract was incubated with plasmid DNA and, before irradiating the samples with UV-R, H(2) O(2) was added. For analysis of DNA single-strand breaks induced by NO, the experiments were performed by incubating the extract with Angeli's salt. In the study on M14 cell line, cell viability was measured using MTT assay. Release of lactate dehydrogenase, a marker of membrane breakdown, was also measured. For the detection of apoptosis, the evaluation of DNA fragmentation (COMET assay) and caspase-3 activity assay were employed. The expression of heat shock protein 70 (Hsp70) was detected by Western blot analysis. Generation of reactive oxygen species was measured by using a fluorescent probe. The extract (demonstrating the synergistic effect of the constituents boldine and flavonoids), showed a protective effect on plasmid DNA and selectively inhibited the growth of melanoma cells. But a novel finding was that apoptosis evoked by this natural product in M14 cells, appears to be mediated, at least in part, via the inhibition of Hsp70 expression, which may be correlated with a modulation of redox-sensitive mechanisms. These results confirm the promising biological properties of Peumus boldus and encourage in-vivo investigations into its potential anti-cancer activity. © 2011 The Authors. JPP © 2011 Royal Pharmaceutical Society.

  20. TRPA1, NMDA receptors and nitric oxide mediate mechanical hyperalgesia induced by local injection of magnesium sulfate into the rat hind paw.

    Science.gov (United States)

    Srebro, Dragana P; Vučković, Sonja M; Savić Vujović, Katarina R; Prostran, Milica Š

    2015-02-01

    Previous studies have shown that while magnesium, an antagonist of the glutamate subtype of N-methyl-D-aspartate receptors, possesses analgesic properties, it can induce writhing in rodents. The aim of this study was to determine the effect and mechanism of action of local (intraplantar) administration of magnesium sulfate (MS) on the paw withdrawal threshold (PWT) to mechanical stimuli. The PWT was evaluated by the electronic von Frey test in male Wistar rats. Tested drugs were either co-administered intraplantarly (i.pl.) with MS or given into the contralateral paw to exclude systemic effects. MS at doses of 0.5, 1.5, 3 and 6.2 mg/paw (i.pl.) induced a statistically significant (as compared to 0.9% NaCl) and dose-dependent mechanical hyperalgesia. Only isotonic MS (250 mmol/l or 6.2% or 6.2 mg/paw) induced mechanical hyperalgesia that lasted at least six hours. Isotonic MS-induced mechanical hyperalgesia was reduced in a dose-dependent manner by co-injection of camphor, a non-selective TRPA1 antagonist (0.3, 1 and 2.5 μg/paw), MK-801, a NMDA receptor antagonist (0.001, 0.025 and 0.1 μg/paw), L-NAME, a non-selective nitric oxide (NO) synthase inhibitor (20, 50 and 100 μg/paw), ARL 17477, a selective neuronal NOS inhibitor (5.7 and 17 μg/paw), SMT, a selective inducible NOS inhibitor (1 and 2.78 μg/paw), and methylene blue, a guanylate cyclase inhibitor (5, 20 and 125 μg/paw). Drugs injected into the contralateral hind paw did not produce significant effects. These results suggest that an i.pl. injection of MS produces local peripheral mechanical hyperalgesia via activation of peripheral TRPA1 and NMDA receptors and peripheral production of NO.

  1. Nitric oxide mediates stretch-induced Ca2+ release via activation of phosphatidylinositol 3-kinase-Akt pathway in smooth muscle.

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    Bin Wei

    Full Text Available BACKGROUND: Hollow smooth muscle organs such as the bladder undergo significant changes in wall tension associated with filling and distension, with attendant changes in muscle tone. Our previous study indicated that stretch induces Ca(2+ release occurs in the form of Ca(2+ sparks and Ca(2+ waves in urinary bladder myocytes. While, the mechanism underlying stretch-induced Ca2+ release in smooth muscle is unknown. METHODOLOGY/PRINCIPAL FINDINGS: We examined the transduction mechanism linking cell stretch to Ca(2+ release. The probability and frequency of Ca(2+ sparks induced by stretch were closely related to the extent of cell extension and the time that the stretch was maintained. Experiments in tissues and single myocytes indicated that mechanical stretch significantly increases the production of nitric oxide (NO and the amplitude and duration of muscle contraction. Stretch-induced Ca(2+ sparks and contractility increases were abrogated by the NO inhibitor L-NAME and were also absent in eNOS knockout mice. Furthermore, exposure of eNOS null mice to exogenously generated NO induced Ca(2+ sparks. The soluble guanylyl cyclase inhibitor ODQ did not inhibit SICR, but this process was effectively blocked by the PI3 kinase inhibitors LY494002 and wortmannin; the phosphorylation of Akt and eNOS were up-regulated by 204+/-28.6% and 258+/-36.8% by stretch, respectively. Moreover, stretch significantly increased the eNOS protein expression level. CONCLUSIONS/SIGNIFICANCE: Taking together, these results suggest that stretch-induced Ca2+ release is NO dependent, resulting from the activation of PI3K/Akt pathway in smooth muscle.

  2. Mechanisms of nitric oxide-mediated inhibition of EMT in cancer: inhibition of the metastasis-inducer Snail and induction of the metastasis-suppressor RKIP.

    Science.gov (United States)

    Baritaki, Stavroula; Huerta-Yepez, Sara; Sahakyan, Anna; Karagiannides, Iordanis; Bakirtzi, Kyriaki; Jazirehi, Ali; Bonavida, Benjamin

    2010-12-15

    The role of nitric oxide (NO) in cancer has been controversial and is based on the levels of NO and the responsiveness of the tumor type. It remains unclear whether NO can inhibit the epithelial to mesenchymal transition (EMT) in cancer cells. EMT induction is mediated, in part, by the constitutive activation of the metastasis-inducer transcription factor, Snail and EMT can be inhibited by the metastasis-suppressor Raf-1 kinase inhibitor protein (RKIP) and E-cadherin. Snail is transcriptionally regulated by NF-κB and in turn, Snail represses RKIP transcription. Hence, we hypothesized that high levels of NO, that inhibit NF-κB activity, may also inhibit Snail and induce RKIP and leading to inhibition of EMT. We show that treatment of human prostate metastatic cell lines with the NO donor, DETANONOate, inhibits EMT and reverses both the mesenchymal phenotype and the cell invasive properties. Further, treatment with DETANONOate inhibits Snail expression and DNA-binding activity in parallel with the upregulation of RKIP and E-cadherin protein levels. The pivotal roles of Snail inhibition and RKIP induction in DETANONOate-mediated inhibition of EMT were corroborated by both Snail silencing by siRNA and by ectopic expression of RKIP. The in vitro findings were validated in vivo in mice bearing PC-3 xenografts and treated with DETANONOate. The present findings show, for the first time, the novel role of high subtoxic concentrations of NO in the inhibition of EMT. Thus, NO donors may exert therapeutic activities in the reversal of EMT and metastasis.

  3. Glutathione plays an essential role in nitric oxide-mediated iron-deficiency signaling and iron-deficiency tolerance in Arabidopsis.

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    Shanmugam, Varanavasiappan; Wang, Yi-Wen; Tsednee, Munkhtsetseg; Karunakaran, Krithika; Yeh, Kuo-Chen

    2015-11-01

    Iron (Fe) deficiency is a common agricultural problem that affects both the productivity and nutritional quality of plants. Thus, identifying the key factors involved in the tolerance of Fe deficiency is important. In the present study, the zir1 mutant, which is glutathione deficient, was found to be more sensitive to Fe deficiency than the wild type, and grew poorly in alkaline soil. Other glutathione-deficient mutants also showed various degrees of sensitivity to Fe-limited conditions. Interestingly, we found that the glutathione level was increased under Fe deficiency in the wild type. By contrast, blocking glutathione biosynthesis led to increased physiological sensitivity to Fe deficiency. On the other hand, overexpressing glutathione enhanced the tolerance to Fe deficiency. Under Fe-limited conditions, glutathione-deficient mutants, zir1, pad2 and cad2 accumulated lower levels of Fe than the wild type. The key genes involved in Fe uptake, including IRT1, FRO2 and FIT, are expressed at low levels in zir1; however, a split-root experiment suggested that the systemic signals that govern the expression of Fe uptake-related genes are still active in zir1. Furthermore, we found that zir1 had a lower accumulation of nitric oxide (NO) and NO reservoir S-nitrosoglutathione (GSNO). Although NO is a signaling molecule involved in the induction of Fe uptake-related genes during Fe deficiency, the NO-mediated induction of Fe-uptake genes is dependent on glutathione supply in the zir1 mutant. These results provide direct evidence that glutathione plays an essential role in Fe-deficiency tolerance and NO-mediated Fe-deficiency signaling in Arabidopsis.

  4. Stimulation of Baroresponsive Parts of the Nucleus of the Solitary Tract Produces Nitric Oxide-mediated Choroidal Vasodilation in Rat Eye

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    Chunyan Li

    2016-10-01

    Full Text Available Preganglionic parasympathetic neurons of the ventromedial part of the superior salivatory nucleus (SSN mediate vasodilation of orbital and choroidal blood vessels, via their projection to the nitrergic pterygopalatine ganglion (PPG neurons that innervate these vessels. We recently showed that the baroresponsive part of the nucleus of the solitary tract (NTS innervates choroidal control parasympathetic preganglionic neurons of SSN in rats. As this projection provides a means by which blood pressure signals may modulate ChBF, we investigated if activation of baroresponsive NTS evokes ChBF increases in rat eye, using Laser Doppler flowmetry to measure ChBF transclerally. We found that electrical activation of ipsilateral baroresponsive NTS and its efferent fiber pathway to choroidal SSN increased mean ChBF by about 40-80% above baseline, depending on current level. The ChBF responses obtained with stimulation of baroresponsive NTS were driven by increases in both choroidal blood volume (i.e. vasodilation and choroidal blood velocity (presumed orbital vessel dilation. Stimulation of baroresponsive NTS, by contrast, yielded no significant mean increases in systemic arterial blood pressure. We further found that the increases in ChBF with NTS stimulation were significantly reduced by administration of the neuronal nitric oxide synthase inhibitor Nω-propyl-l-arginine (NPA, thus implicating nitrergic PPG terminals in the NTS-elicited ChBF increases. Our results show that NTS neurons projecting to choroidal SSN do mediate increase in ChBF, and thus suggest a role of baroresponsive NTS in the blood pressure-dependent regulation of ChBF.

  5. Stimulation of Baroresponsive Parts of the Nucleus of the Solitary Tract Produces Nitric Oxide-mediated Choroidal Vasodilation in Rat Eye

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    Li, Chunyan; Fitzgerald, Malinda E. C.; Del Mar, Nobel; Reiner, Anton

    2016-01-01

    Preganglionic parasympathetic neurons of the ventromedial part of the superior salivatory nucleus (SSN) mediate vasodilation of orbital and choroidal blood vessels, via their projection to the nitrergic pterygopalatine ganglion (PPG) neurons that innervate these vessels. We recently showed that the baroresponsive part of the nucleus of the solitary tract (NTS) innervates choroidal control parasympathetic preganglionic neurons of SSN in rats. As this projection provides a means by which blood pressure (BP) signals may modulate choroidal blood flow (ChBF), we investigated if activation of baroresponsive NTS evokes ChBF increases in rat eye, using Laser Doppler Flowmetry (LDF) to measure ChBF transclerally. We found that electrical activation of ipsilateral baroresponsive NTS and its efferent fiber pathway to choroidal SSN increased mean ChBF by about 40–80% above baseline, depending on current level. The ChBF responses obtained with stimulation of baroresponsive NTS were driven by increases in both choroidal blood volume (ChBVol; i.e., vasodilation) and choroidal blood velocity (ChBVel; possibly due to orbital vessel dilation). Stimulation of baroresponsive NTS, by contrast, yielded no significant mean increases in systemic arterial blood pressure (ABP). We further found that the increases in ChBF with NTS stimulation were significantly reduced by administration of the neuronal nitric oxide (NO) synthase inhibitor Nω-propyl-l-arginine (NPA), thus implicating nitrergic PPG terminals in the NTS-elicited ChBF increases. Our results show that the NTS neurons projecting to choroidal SSN do mediate increase in ChBF, and thus suggest a role of baroresponsive NTS in the BP-dependent regulation of ChBF. PMID:27774055

  6. Changes of nitric oxide synthase and cyclic guanosine monophosphate in form deprivation myopia in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    WU Jie; LIU Qiong; YANG Xiao; YANG Hui; WANG Xin-mei; ZENG Jun-wen

    2007-01-01

    Background The form deprivation(FD)reduces spatial contrasts and induces myopia. Nitric oxide and cyclic guanosine monophosphate(cGMP)are involved in visual signal transmission.This study investigated changes in nitric oxide synthase(NOS)activity and cGMP concentration in ocular tissues in acute and chronic form deprivation myopia.Methods Guinea pigs had one eye covered by translucent glass for 7,14 or 21 days.Untreated litter mates were used as controls.NOS activity and cGMP concentrations in the retinal,choroidal and scleral tissues of FD eyes and controleyes were analyzed by radioimmunoassay after various durations of FD.The expression of NOS subtypes was identified by immunohistochemistry.Results Myopia was successfully induced in FD eyes after 14 days.Compared with control groups,the retinal NOS activity and cGMP concentrations in the FD eyes significantly increased after 14 and 21 days while the retinal NOS activity in the FD eyes was transiently suppressed by 7 days of FD.The NOS activity and cGMP concentrations of choroid and sclera in the FD eyes were higher than in the control groups at 21 days.The three isoenzymes of nitric oxide synthase were detected in the ocular tissues of guinea pigs.Conclusions The NOS activity and cGMP concentrations were upregulated after chronic FD and the retinal NOS activity was transiently suppressed at acute FD.The function of elevated NOS activity may be mediated by cGMP.

  7. Nitric oxide mediates the vagal protective effect on ventricular fibrillation via effects on action potential duration restitution in the rabbit heart.

    Science.gov (United States)

    Brack, Kieran E; Patel, Vanlata H; Coote, John H; Ng, G André

    2007-09-01

    We have previously shown that direct vagus nerve stimulation (VNS) reduces the slope of action potential duration (APD) restitution while simultaneously protecting the heart against induction of ventricular fibrillation (VF) in the absence of any sympathetic activity or tone. In the current study we have examined the role of nitric oxide (NO) in the effect of VNS. Monophasic action potentials were recorded from a left ventricular epicardial site on innervated, isolated rabbit hearts (n = 7). Standard restitution, effective refractory period (ERP) and VF threshold (VFT) were measured at baseline and during VNS in the presence of the NO synthase inhibitor N(G)-nitro-L-arginine (L-NA, 200 microm) and during reversing NO blockade with L-arginine (L-Arg, 1 mm). Data represent the mean +/- S.E.M. The restitution curve was shifted upwards and became less steep with VNS when compared to baseline. L-NA blocked the effect of VNS whereas L-Arg restored the effect of VNS. The maximum slope of restitution was reduced from 1.17 +/- 0.14 to 0.60 +/- 0.09 (50 +/- 5%, P < 0.0001) during control, from 0.98 +/- 0.14 to 0.93 +/- 0.12 (2 +/- 10%, P = NS) in the presence of L-NA and from 1.16 +/- 0.17 to 0.50 +/- 0.10 (41 +/- 9%, P = 0.003) with L-Arg plus L-NA. ERP was increased by VNS in control from 119 +/- 6 ms to 130 +/- 6 ms (10 +/- 5%, P = 0.045) and this increase was not affected by L-NA (120 +/- 4 to 133 +/- 4 ms, 11 +/- 3%, P = 0.0019) or L-Arg with L-NA (114 +/- 4 to 123 +/- 4 ms, 8 +/- 2%, P = 0.006). VFT was increased from 3.0 +/- 0.3 to 5.8 +/- 0.5 mA (98 +/- 12%, P = 0.0017) in control, 3.4 +/- 0.4 to 3.8 +/- 0.5 mA (13 +/- 12%, P = 0.6) during perfusion with L-NA and 2.5 +/- 0.4 to 6.0 +/- 0.7 mA (175 +/- 50%, P = 0.0017) during perfusion with L-Arg plus L-NA. Direct VNS increased VFT and flattened the slope of APD restitution curve in this isolated rabbit heart preparation with intact autonomic nerves. These effects were blocked using L-NA and reversed by replenishing

  8. Cyclic nitroxides inhibit the toxicity of nitric oxide-derived oxidants: mechanisms and implications

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    Ohara Augusto

    2008-03-01

    Full Text Available The substantial therapeutic potential of tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy and related cyclic nitroxides as antioxidants has stimulated innumerous studies of their reactions with reactive oxygen species. In comparison, reactions of nitroxides with nitric oxide-derived oxidants have been less frequently investigated. Nevertheless, this is relevant because tempol has also been shown to protect animals from injuries associated with inflammatory conditions, which are characterized by the increased production of nitric oxide and its derived oxidants. Here, we review recent studies addressing the mechanisms by which cyclic nitroxides attenuate the toxicity of nitric oxidederived oxidants. As an example, we present data showing that tempol protects mice from acetaminophen-induced hepatotoxicity and discuss the possible protection mechanism. In view of the summarized studies, it is proposed that nitroxides attenuate tissue injury under inflammatory conditions mainly because of their ability to react rapidly with nitrogen dioxide and carbonate radical. In the process the nitroxides are oxidized to the corresponding oxammonium cation, which, in turn, can be recycled back to the nitroxides by reacting with upstream species, such as peroxynitrite and hydrogen peroxide, or with cellular reductants. An auxiliary protection mechanism may be down-regulation of inducible nitric oxide synthase expression. The possible therapeutic implications of these mechanisms are addressed.O considerável potencial terapêutico de tempol (4-hidroxi-2,2, 6,6-tetrametil-1piperiniloxila e nitróxidos cíclicos relacionados como antioxidantes tem estimulado inúmeros estudos de suas reações com espécies reativas derivadas de oxigênio. Em comparação, as reações de nitróxidos com oxidantes derivados do óxido nítrico têm sido investigadas menos frequentemente. Todavia, essas reações são relevantes porque o tempol é também capaz de proteger

  9. Elevated nitric oxide and 3',5' cyclic guanosine monophosphate levels in patients with alcoholic cirrhosis

    Institute of Scientific and Technical Information of China (English)

    C(i)ntia Siqueira; Miguel Carneiro de Moura; Ana J(u)lia Pedro; Paula Rocha

    2008-01-01

    AIM: To evaluate whether serum levels of nitric oxide (NO') and plasma levels of cyclic guanosine monophosphate (Cgmp) and total glutathione (GSH) are altered in patients with alcoholic cirrhosis and to examine their correlation with the severity of liver disease.METHODS: Twenty-six patients with alcoholic liver cirrhosis were studied. Serum levels of NO· and plasma levels of cGMP and GSH were measured in 7 patients with compensated alcoholic cirrhosis (Child-Pugh A) and 19 patients with advanced cirrhosis (Child-Pugh B and C).The model for end-stage liver disease (MELD) score was evaluated. Sixteen healthy volunteers served as controls.Liver enzymes and creatinine levels were also tested.RESULTS: NO· and cGMP levels were higher in patients with Child-Pugh B and C cirrhosis than in Child-Pugh A cirrhosis or controls (NO·: 21.70 ± 8.07 vs 11.70 ± 2.74; 21.70 ± 8.07 vs 7.26 ± 2.47 μmol/L, respectively;P < 0.001) and (cGMP: 20.12 ± 6.62 vs 10.14 ± 2.78;20.12 ± 6.62 vs 4.95 ± 1.21 pmol/L, respectively; P <0.001). Total glutathione levels were lower in patients with Child-Pugh B and C cirrhosis than in patients with Child-Pugh A cirrhosis or controls (16.04 ± 6.06 vs 23.01 ± 4.38 or 16.04 ± 6.06 vs 66.57 ± 26.23 μmol/L,respectively; P < 0.001). There was a significant correlation between NO· and cGMP levels in all patients with alcoholic cirrhosis. A significant negative correlation between reduced glutathione/glutathione disulfide and the MELD score was found in all cirrhotic patients. CONCLUSION: Our results suggest a role for oxidative stress in alcoholic liver cirrhosis, which is more significant in decompensated patients with higher levels of NO· and cGMP and lower GSH levels than in compensated and control patients. Altered mediator levels in decompensated patients may influence the hemodynamic changes in and progression of liver disease.

  10. Role of nitric oxide and cyclic GMP signaling in melanocyte response to hypergravity

    Science.gov (United States)

    Ivanova, Krassimira; Lambers, Britta; Tsiockas, Wasiliki; Block, Ingrid; Gerzer, Rupert

    Nitric oxide (NO) has a prominent role in many (patho)physiological processes in the skin including erythema, inflammation, and cancerogenesis. The soluble guanylyl cyclase (sGC), a key transducer in NO signaling, catalyzes the formation of the second messenger guanosine 3´,5´-cyclic monophosphate (cyclic cGMP or cGMP). For human melanocytes, which are responsible for skin pigmentation by synthesizing the pigment melanin, it has been reported that the NO/sGC/cGMP pathway is involved in UVB-induced melanogenesis. Melanin acts as a scavenger for free radicals that may arise during metabolic stress. It may also act as a photosensitizer that generates active oxygen species upon UV irradiation, which may initiate hypopigmentary disorders (e.g., vitiligo) as well as UV-induced oncogene cell transformation. In addition, melanoma, a deadly skin cancer, which arises from transformed melanocytes, is characterized by a resistance to chemotherapy. In our studies we have shown that NO can induce perturbation of melanocyte-extracellular matrix component interactions, which may contribute to loss of melanocytes or melanoma metastasis. Such NO effects appear to be modulated partly via cGMP. Moreover, we found that different guanylyl cyclase isoforms are responsible for cGMP synthesis in melanocytic cells. Normal human melanocytes and nonmetastatic melanoma cells predominantly express sGC, which appears to be associated with melanogenesis, whereas absence of NO-sensitive GC, but up-regulated activities of the natriuretic peptide-sensitive membrane guanylyl cyclase isoforms were found in highly metastatic phenotypes. Due to the growing interest in the regulation of signaling activities in normal and transformed cells under altered gravity conditions, we have further investigated whether the NO/cGMP signaling is involved in melanocyte response to gravitational stress. We found that normal human melanocytes and non-metastatic melanoma cell lines, but not highly metastatic cells

  11. Cyclic Stretch Induces Inducible Nitric Oxide Synthase and Soluble Guanylate Cyclase in Pulmonary Artery Smooth Muscle Cells

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    Kathryn N. Farrow

    2013-02-01

    Full Text Available In the pulmonary vasculature, mechanical forces such as cyclic stretch induce changes in vascular signaling, tone and remodeling. Nitric oxide is a potent regulator of soluble guanylate cyclase (sGC, which drives cGMP production, causing vasorelaxation. Pulmonary artery smooth muscle cells (PASMCs express inducible nitric oxide synthase (iNOS, and while iNOS expression increases during late gestation, little is known about how cyclic stretch impacts this pathway. In this study, PASMC were subjected to cyclic stretch of 20% amplitude and frequency of 1 Hz for 24 h and compared to control cells maintained under static conditions. Cyclic stretch significantly increased cytosolic oxidative stress as compared to static cells (62.9 ± 5.9% vs. 33.3 ± 5.7% maximal oxidation, as measured by the intracellular redox sensor roGFP. Cyclic stretch also increased sGCβ protein expression (2.5 ± 0.9-fold, sGC activity (1.5 ± 0.2-fold and cGMP levels (1.8 ± 0.2-fold, as well as iNOS mRNA and protein expression (3.0 ± 0.9 and 2.6 ± 0.7-fold, respectively relative to control cells. An antioxidant, recombinant human superoxide dismutase (rhSOD, significantly decreased stretch-induced cytosolic oxidative stress, but did not block stretch-induced sGC activity. Inhibition of iNOS with 1400 W or an iNOS-specific siRNA inhibited stretch-induced sGC activity by 30% and 68% respectively vs. static controls. In conclusion, cyclic stretch increases sGC expression and activity in an iNOS-dependent manner in PASMC from fetal lambs. The mechanism that produces iNOS and sGC upregulation is not yet known, but we speculate these effects represent an early compensatory mechanism to counteract the effects of stretch-induced oxidative stress. A better understanding of the interplay between these two distinct pathways could provide key insights into future avenues to treat infants with pulmonary hypertension.

  12. Nitric oxide donor NOR 3 inhibits ketogenesis from oleate in isolated rat hepatocytes by a cyclic GMP-independent mechanism.

    Science.gov (United States)

    Nomura, T; Ohtsuki, M; Matsui, S; Sumi-Ichinose, C; Nomura, H; Hagino, Y

    1998-01-01

    Studies were conducted to clarify the effects of nitric oxide donors NOR 3 ((+/-)-(E)-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexeneamide, FK409), SIN-1 (3-morpholinosydnonimine) and SNAP (S-nitroso-N-acetylpenicillamine) on the accumulation of cGMP and cAMP and Ca2+ mobilization as well as ketogenesis from oleate in isolated rat hepatocytes. NOR 3 caused inhibition of ketogenesis from oleate along with stimulation of cGMP accumulation in rat hepatocytes, whereas SIN-1 and SNAP exerted no effect on ketogenesis despite their marked stimulation of cGMP accumulation. Although the nitric oxide trapping agent, carboxy-PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide), antagonized the stimulation by NOR 3 of cGMP accumulation, it failed to modulate the anti-ketogenic action of NOR 3. Furthermore, neither 8-bromoguanosine-3',5'-cyclic monophosphate nor N2,2'-O-dibutyrylguanosine-3',5'-cyclic monophosphate mimicked the anti-ketogenic action of NOR 3. It is concluded in the present study that NOR 3-induced inhibition of ketogenesis in rat hepatocytes is not mediated by cGMP. The present study revealed that the remaining structure of NOR 3 from which nitric oxide had been spontaneously released had no anti-ketogenic action. We first and clearly demonstrated that nitrite production was dramatically enhanced when NOR 3 was incubated in the presence of rat hepatocytes. The mechanism whereby NOR 3 inhibits ketogenesis in rat hepatocytes will be discussed.

  13. Lower urinary tract symptoms/benign prostatic hypertrophy and vascular function: Role of the nitric oxide-phosphodiesterase type 5-cyclic guanosine 3',5'-monophosphate pathway.

    Science.gov (United States)

    Higashi, Yukihito

    2017-06-01

    It is well known that there is an association of lower urinary tract symptoms/benign prostatic hypertrophy with cardiovascular disease, suggesting that lower urinary tract symptoms/benign prostatic hypertrophy is a risk factor for cardiovascular events. Vascular function, including endothelial function and vascular smooth muscle function, is involved in the pathogenesis, maintenance and development of atherosclerosis, leading to cardiovascular events. Vascular dysfunction per se should also contribute to lower urinary tract symptoms/benign prostatic hypertrophy. Both lower urinary tract symptoms/benign prostatic hypertrophy and vascular dysfunction have cardiovascular risk factors, such as hypertension, dyslipidemia, diabetes mellitus, aging, obesity and smoking. Inactivation of the phosphodiesterase type 5-cyclic guanosine 3',5'-monophosphate-nitric oxide pathway causes lower urinary tract symptoms/benign prostatic hypertrophy through an enhancement of sympathetic nervous activity, endothelial dysfunction, increase in Rho-associated kinase activity and vasoconstriction, and decrease in blood flow of pelvic viscera. Both endogenous nitric oxide and exogenous nitric oxide act as vasodilators on vascular smooth muscle cells through an increase in the content of cyclic guanosine 3',5'-monophosphate, which is inactivated by phosphodiesterase type 5. In a clinical setting, phosphodiesterase type 5 inhibitors are widely used in patients with lower urinary tract symptoms/benign prostatic hypertrophy. Phosphodiesterase type 5 inhibitors might have beneficial effects on vascular function through not only inhibition of cyclic guanosine 3',5'-monophosphate degradation, but also increases in testosterone levels and nitric oxide bioavailability, increase in the number and improvement of the function of endothelial progenitor cells, and decrease in insulin resistance. In the present review, the relationships between lower urinary tract symptoms/benign prostatic hypertrophy, the

  14. Nitric oxide mediates the fungal elicitor-induced puerarin biosynthesis in Pueraria thomsonii Benth. suspension cells through a salicylic acid (SA)-dependent and a jasmonic acid (JA)-dependent signal pathway

    Institute of Scientific and Technical Information of China (English)

    XU Maojun; DONG Jufang; ZHU Muyuan

    2006-01-01

    Nitric oxide (NO) has emerged as a key signaling molecule in plant secondary metabolite biosynthesis recently. In order to investigate the molecular basis of NO signaling in elicitor-induced secondary metabolite biosynthesis of plant cells, we determined the contents of NO, salicylic acid (SA), jasmonic acid (JA), and puerarin in Pueraria thomsonii Benth. suspension cells treated with the elicitors prepared from cell walls of Penicillium citrinum. The results showed that the fungal elicitor induced NO burst, SA accumulation and puerarin production of P. thomsonii Benth. cells. The elicitor-induced SA accumulation and puerarin production was suppressed by nitric oxide specific scavenger cPITO, indicating that NO was essential for elicitor-induced SA and puerarin biosynthesis in P. thomsonii Benth. cells. In transgenic NahG P. thomsonii Benth. cells, the fungal elicitor also induced puerarin biosynthesis, NO burst, and JA accumulation, though the SA biosynthesis was impaired. The elicitor-induced JA accumulation in transgenic cells was blocked by cPITO, which suggested that JA acted downstream of NO and its biosynthesis was controlled by NO. External application of NO via its donor sodium nitroprusside (SNP) enhanced puerarin biosynthesis in transgenic NahG P. thomsonii Benth. cells, and the NO-triggered puerarin biosynthesis was suppressed by JA inhibitors IBU and NDGA, which indicated that NO induced puerarin production through a JA-dependent signal pathway in the transgenic cells. Exogenous application of SA suppressed the elicitor-induced JA biosynthesis and reversed the inhibition of IBU and NDGA on elicitor-induced puerarin accumulation in transgenic cells, which indicated that SA inhibited JA biosynthesis in the cells and that SA might be used as a substitute for JA to mediate the elicitor- and NO-induced puerarin biosynthesis. It was, therefore, concluded that NO might mediate the elicitor-induced puerarin biosynthesis through SA- and JA-dependent signal

  15. The nitric oxide-cyclic GMP pathway regulates FoxO and alters dopaminergic neuron survival in Drosophila.

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    Tomoko Kanao

    Full Text Available Activation of the forkhead box transcription factor FoxO is suggested to be involved in dopaminergic (DA neurodegeneration in a Drosophila model of Parkinson's disease (PD, in which a PD gene product LRRK2 activates FoxO through phosphorylation. In the current study that combines Drosophila genetics and biochemical analysis, we show that cyclic guanosine monophosphate (cGMP-dependent kinase II (cGKII also phosphorylates FoxO at the same residue as LRRK2, and Drosophila orthologues of cGKII and LRRK2, DG2/For and dLRRK, respectively, enhance the neurotoxic activity of FoxO in an additive manner. Biochemical assays using mammalian cGKII and FoxO1 reveal that cGKII enhances the transcriptional activity of FoxO1 through phosphorylation of the FoxO1 S319 site in the same manner as LRRK2. A Drosophila FoxO mutant resistant to phosphorylation by DG2 and dLRRK (dFoxO S259A corresponding to human FoxO1 S319A suppressed the neurotoxicity and improved motor dysfunction caused by co-expression of FoxO and DG2. Nitric oxide synthase (NOS and soluble guanylyl cyclase (sGC also increased FoxO's activity, whereas the administration of a NOS inhibitor L-NAME suppressed the loss of DA neurons in aged flies co-expressing FoxO and DG2. These results strongly suggest that the NO-FoxO axis contributes to DA neurodegeneration in LRRK2-linked PD.

  16. Nitric oxide mediates root K+/Na+ balance in a mangrove plant, Kandelia obovata, by enhancing the expression of AKT1-type K+ channel and Na+/H+ antiporter under high salinity.

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    Juan Chen

    Full Text Available It is well known that nitric oxide (NO enhances salt tolerance of glycophytes. However, the effect of NO on modulating ionic balance in halophytes is not very clear. This study focuses on the role of NO in mediating K(+/Na(+ balance in a mangrove species, Kandelia obovata Sheue, Liu and Yong. We first analyzed the effects of sodium nitroprusside (SNP, an NO donor, on ion content and ion flux in the roots of K. obovata under high salinity. The results showed that 100 μM SNP significantly increased K(+ content and Na(+ efflux, but decreased Na(+ content and K(+ efflux. These effects of NO were reversed by specific NO synthesis inhibitor and scavenger, which confirmed the role of NO in retaining K(+ and reducing Na(+ in K. obovata roots. Using western-blot analysis, we found that NO increased the protein expression of plasma membrane (PM H(+-ATPase and vacuolar Na(+/H(+ antiporter, which were crucial proteins for ionic balance. To further clarify the molecular mechanism of NO-modulated K(+/Na(+ balance, partial cDNA fragments of inward-rectifying K(+ channel, PM Na(+/H(+ antiporter, PM H(+-ATPase, vacuolar Na(+/H(+ antiporter and vacuolar H(+-ATPase subunit c were isolated. Results of quantitative real-time PCR showed that NO increased the relative expression levels of these genes, while this increase was blocked by NO synthesis inhibitors and scavenger. Above results indicate that NO greatly contribute to K(+/Na(+ balance in high salinity-treated K. obovata roots, by activating AKT1-type K(+ channel and Na(+/H(+ antiporter, which are the critical components in K(+/Na(+ transport system.

  17. Cell-specific expression and immunolocalization of nitric oxide synthase isoforms and the related nitric oxide/cyclic GMP signaling pathway in the ovaries of neonatal and immature rats

    Institute of Scientific and Technical Information of China (English)

    Wei ZHANG; Quan-wei WEI; Zheng-chao WANG; Wei DING; Wei WANG; Fang-xiong SHI

    2011-01-01

    Objective: The present study is designed to investigate the cellular expressions and immunolocalizations of three different nitric oxide synthase(NOS)isoforms and the related nitric oxide(NO)/cyclic guanosine monophosphate(cGMP)signaling pathway in the ovaries of neonatal and immature rats.Methods: The ovaries were obtained from ICR(Institute for Cancer Research)female Sprague-Dawley rats at postnatal days 1,5,7,10,and 19.Then we carried out the histologic examination,immunohistochemistry,measurement of NOS activity,and modifications within the NO/cGMP pathway.Results: During postnatal days 1,5,7,10,and 19,all three isoforms of NOS were mainly localized to the oocytes and expressed as a gradual increase in granulosa cells and theca cells within the growing follicle.The ovarian total NOS activities and NO levels were increased at postnatal days 7 and 10 compared with other days.Conclusions: Our findings suggest that the locally produced NO and the NO/NOS signaling systems are involved in the follicular development to puberty.

  18. Kinetics of Acid-Catalyzed Dehydration of Cyclic Hemiacetals in Organic Aerosol Particles in Equilibrium with Nitric Acid Vapor.

    Science.gov (United States)

    Ranney, April P; Ziemann, Paul J

    2016-04-28

    Previous studies have shown that 1,4-hydroxycarbonyls, which are often major products of the atmospheric oxidation of hydrocarbons, can undergo acid-catalyzed cyclization and dehydration in aerosol particles to form highly reactive unsaturated dihydrofurans. In this study the kinetics of dehydration of cyclic hemiacetals, the rate-limiting step in this process, was investigated in a series of environmental chamber experiments in which secondary organic aerosol (SOA) containing cyclic hemiacetals was formed from the reaction of n-pentadecane with OH radicals in dry air in the presence of HNO3. A particle beam mass spectrometer was used to monitor the formation and dehydration of cyclic hemiacetals in real time, and SOA and HNO3 were quantified in filter samples by gravimetric analysis and ion chromatography. Measured dehydration rate constants increased linearly with increasing concentration of HNO3 in the gas phase and in SOA, corresponding to catalytic rate constants of 0.27 h(-1) ppmv(-1) and 7.0 h(-1) M(-1), respectively. The measured Henry's law constant for partitioning of HNO3 into SOA was 3.7 × 10(4) M atm(-1), ∼25% of the value for dissolution into water, and the acid dissociation constant was estimated to be water. The results indicate that HNO3 was only weakly dissociated in the SOA and that dehydration of cyclic hemiacetals was catalyzed by molecular HNO3 rather than by H(+). The Henry's law constant and kinetics relationships measured here can be used to improve mechanisms and models of SOA formation from the oxidation of hydrocarbons in dry air in the presence of NOx, which are conditions commonly used in laboratory studies. The fate of cyclic hemiacetals in the atmosphere, where the effects of higher relative humidity, organic/aqueous phase separation, and acid catalysis by molecular H2SO4 and/or H(+) are likely to be important, is discussed.

  19. Modification of Tau by 8-Nitroguanosine 3',5'-Cyclic Monophosphate (8-Nitro-cGMP): EFFECTS OF NITRIC OXIDE-LINKED CHEMICAL MODIFICATION ON TAU AGGREGATION.

    Science.gov (United States)

    Yoshitake, Jun; Soeda, Yoshiyuki; Ida, Tomoaki; Sumioka, Akio; Yoshikawa, Misato; Matsushita, Kenji; Akaike, Takaaki; Takashima, Akihiko

    2016-10-21

    Neurofibrillar tangles caused by intracellular hyperphosphorylated tau inclusion and extracellular amyloid β peptide deposition are hallmarks of Alzheimer's disease. Tau contains one or two cysteine residues in three or four repeats of the microtubule binding region following alternative splicing of exon 10, and formation of intermolecular cysteine disulfide bonds accelerates tau aggregation. 8-Nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) acts as a novel second messenger of nitric oxide (NO) by covalently binding cGMP to cysteine residues by electrophilic properties, a process termed protein S-guanylation. Here we studied S-guanylation of tau and its effects on tau aggregation. 8-Nitro-cGMP exposure induced S-guanylation of tau both in vitro and in tau-overexpressed HEK293T cells. S-guanylated tau inhibited heparin-induced tau aggregation in a thioflavin T assay. Atomic force microscopy observations indicated that S-guanylated tau could not form tau granules and fibrils. Further biochemical analyses showed that S-guanylated tau was inhibited at the step of tau oligomer formation. In P301L tau-expressing Neuro2A cells, 8-nitro-cGMP treatment significantly reduced the amount of sarcosyl-insoluble tau. NO-linked chemical modification on cysteine residues of tau could block tau aggregation, and therefore, increasing 8-nitro-cGMP levels in the brain could become a potential therapeutic strategy for Alzheimer's disease. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Differential Contribution of the Guanylyl Cyclase-Cyclic GMP-Protein Kinase G Pathway to the Proliferation of Neural Stem Cells Stimulated by Nitric Oxide

    Directory of Open Access Journals (Sweden)

    Bruno P. Carreira

    2012-02-01

    Full Text Available Nitric oxide (NO is an important inflammatory mediator involved in the initial boost in the proliferation of neural stem cells following brain injury. However, the mechanisms underlying the proliferative effect of NO are still unclear. The aim of this work was to investigate whether cyclic GMP (cGMP and the cGMP-dependent kinase (PKG are involved in the proliferative effect triggered by NO in neural stem cells. For this purpose, cultures of neural stem cells isolated from the mouse subventricular zone (SVZ were used. We observed that long-term exposure to the NO donor (24 h, NOC-18, increased the proliferation of SVZ cells in a cGMP-dependent manner, since the guanylate cyclase inhibitor, ODQ, prevented cell proliferation. Similarly to NOC-18, the cGMP analogue, 8-Br-cGMP, also increased cell proliferation. Interestingly, shorter exposures to NO (6 h increased cell proliferation in a cGMP-independent manner via the ERK/MAP kinase pathway. The selective inhibitor of PKG, KT5823, prevented the proliferative effect induced by NO at 24 h but not at 6 h. In conclusion, the proliferative effect of NO is initially mediated by the ERK/MAPK pathway, and at later stages by the GC/cGMP/PKG pathway. Thus, our work shows that NO induces neural stem cell proliferation by targeting these two pathways in a biphasic manner.

  1. Anti-allodynic effect of mangiferin in neuropathic rats: Involvement of nitric oxide-cyclic GMP-ATP sensitive K(+) channels pathway and serotoninergic system.

    Science.gov (United States)

    de Los Monteros-Zuñiga, Antonio Espinosa; Izquierdo, Teresa; Quiñonez-Bastidas, Geovanna Nallely; Rocha-González, Héctor Isaac; Godínez-Chaparro, Beatriz

    The neurobiology of neuropathic pain is caused by injury in the central or peripheral nervous system. Recent evidence points out that mangiferin shows anti-nociceptive effect in inflammatory pain. However, its role in inflammatory and neuropathic pain and the possible mechanisms of action are not yet established. The purpose of this study was to determine the possible anti-allodynic effect of mangiferin in rats with spinal nerve ligation (SNL). Furthermore, we sought to investigate the possible mechanisms of action that contribute to these effects. Mechanical allodynia to stimulation with the von Frey filaments was measured by the up and down method. Intrathecal administration of mangiferin prevented, in a dose-dependent fashion, SNL-induced mechanical allodynia. Mangiferin-induced anti-allodynia was prevented by the intrathecal administration of L-NAME (100μg/rat, non-selective nitric oxide synthase inhibitor), ODQ (10μg/rat, inhibitor of guanylate-cyclase) and glibenclamide (50μg/rat, channel blocker of ATP-sensitive K(+) channels). Moreover, methiothepin (30μg/rat, non-selective 5-HT receptor antagonist), WAY-100635 (6μg/rat, selective 5-HT1A receptor antagonist), SB-224289 (5μg/rat, selective 5-HT1B receptor antagonist), BRL-15572 (4μg/rat, selective 5-HT1D receptor antagonist) and SB-659551 (6μg/rat, selective 5-HT5A receptor antagonist), but not naloxone (50μg/rat, non-selective opioid receptor antagonist), were able to prevent mangiferin-induced anti-allodynic effect. These data suggest that the anti-allodynic effect induced by mangiferin is mediated at least in part by the serotoninergic system, involving the activation of 5-HT1A/1B/1D/5A receptors, as well as the nitric oxide-cyclic GMP-ATP-sensitive K(+) channels pathway, but not by the opioidergic system, in the SNL model of neuropathic pain in rats.

  2. Systems Pharmacology and Rational Polypharmacy: Nitric Oxide−Cyclic GMP Signaling Pathway as an Illustrative Example and Derivation of the General Case

    Science.gov (United States)

    Garmaroudi, Farshid S.; Handy, Diane E.; Liu, Yang-Yu; Loscalzo, Joseph

    2016-01-01

    Impaired nitric oxide (NO˙)-cyclic guanosine 3', 5'-monophosphate (cGMP) signaling has been observed in many cardiovascular disorders, including heart failure and pulmonary arterial hypertension. There are several enzymatic determinants of cGMP levels in this pathway, including soluble guanylyl cyclase (sGC) itself, the NO˙-activated form of sGC, and phosphodiesterase(s) (PDE). Therapies for some of these disorders with PDE inhibitors have been successful at increasing cGMP levels in both cardiac and vascular tissues. However, at the systems level, it is not clear whether perturbation of PDE alone, under oxidative stress, is the best approach for increasing cGMP levels as compared with perturbation of other potential pathway targets, either alone or in combination. Here, we develop a model-based approach to perturbing this pathway, focusing on single reactions, pairs of reactions, or trios of reactions as targets, then monitoring the theoretical effects of these interventions on cGMP levels. Single perturbations of all reaction steps within this pathway demonstrated that three reaction steps, including the oxidation of sGC, NO˙ dissociation from sGC, and cGMP degradation by PDE, exerted a dominant influence on cGMP accumulation relative to other reaction steps. Furthermore, among all possible single, paired, and triple perturbations of this pathway, the combined perturbations of these three reaction steps had the greatest impact on cGMP accumulation. These computational findings were confirmed in cell-based experiments. We conclude that a combined perturbation of the oxidatively-impaired NO˙-cGMP signaling pathway is a better approach to the restoration of cGMP levels as compared with corresponding individual perturbations. This approach may also yield improved therapeutic responses in other complex pharmacologically amenable pathways. PMID:26985825

  3. Hypercapnic vasodilatation in isolated rat basilar arteries is exerted via low pH and does not involve nitric oxide synthase stimulation or cyclic GMP production

    DEFF Research Database (Denmark)

    You, J P; Wang, Qian; Zhang, W

    1994-01-01

    The relaxant effect of hypercapnia (15% CO2) was studied in isolated circular segments of rat basilar arteries with intact endothelium. The nitric oxide synthase inhibitor nitro-L-arginine (L-NOARG) and the cytosolic guanylate cyclase inhibitor methylene blue (MB), significantly reduced...

  4. The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-05-11

    Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  5. Role of iron in the nitric oxide-mediated fungicidal mechanism of IFN-gamma-activated murine macrophages against Paracoccidioides brasiliensis conidia Papel do ferro no mecanismo fungicida mediado pelo óxido n��trico de macrófagos murinos ativados com IFN-gama contra conídias do Paracoccidioides brasiliensis

    Directory of Open Access Journals (Sweden)

    Angel Gonzalez

    2007-02-01

    Full Text Available Iron is an essential growth element of virtually all microorganisms and its restriction is one of the mechanisms used by macrophages to control microbial multiplication. Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis, an important systemic mycosis in Latin America, is inhibited in its conidia-to-yeast conversion in the absence of iron. We studied the participation of iron in the nitric oxide (NO-mediated fungicidal mechanism against conidia. Peritoneal murine macrophages activated with 50U/mL of IFN-gamma or treated with 35 µM Deferoxamine (DEX and infected with P. brasiliensis conidia, were co-cultured and incubated for 96 h in the presence of different concentrations of holotransferrin (HOLO and FeS0(4. The supernatants were withdrawn in order to assess NO2 production by the Griess method. The monolayers were fixed, stained and observed microscopically. The percentage of the conidia-to-yeast transition was estimated by counting 200 intracellular propagules. IFN-gamma-activated or DEX-treated Mthetas presented marked inhibition of the conidia-to-yeast conversion (19 and 56%, respectively in comparison with non-activated or untreated Mthetas (80%. IFN-gamma-activated macrophages produced high NO levels in comparison with the controls. Additionally, when the activated or treated-macrophages were supplemented with iron donors (HOLO or FeSO4, the inhibitory action was reversed, although NO production remained intact. These results suggest that the NO-mediated fungicidal mechanism exerted by IFN-gamma-activated macrophages against P. brasiliensis conidia, is dependent of an iron interaction.O ferro é elemento essencial para o crescimento de microrganismos e sua limitação é um dos mecanismos usados por macrófagos para controlar a multiplicação microbiana. Paracoccidioides brasiliensis, o agente da paracoccidioidomicose, uma das micoses sistêmicas mais importantes na América Latina, é inibido em sua conversão de con

  6. Nitric oxide-soluble guanylyl cyclase-cyclic GMP signaling in the striatum: New targets for the treatment of Parkinson's disease?

    Directory of Open Access Journals (Sweden)

    Anthony R West

    2011-06-01

    Full Text Available Striatal nitric oxide (NO-producing interneurons play an important role in the regulation of corticostriatal synaptic transmission and motor behavior. Striatal NO synthesis is driven by concurrent activation of NMDA and dopamine (DA D1 receptors. NO diffuses into the dendrites of medium-sized spiny neurons (MSNs which contain high levels of NO receptors called soluble guanylyl cyclases (sGC. NO-mediated activation of sGC leads to the synthesis of the second messenger cGMP. In the intact striatum, transient elevations in intracellular cGMP primarily act to increase neuronal excitability and to facilitate glutamatergic corticostriatal transmission. NO-cGMP signaling also functionally opposes the inhibitory effects of DA D2 receptor activation on corticostriatal transmission. Not surprisingly, abnormal striatal NO-sGC-cGMP signaling becomes apparent following striatal DA depletion, an alteration thought to contribute to pathophysiological changes observed in basal ganglia circuits in Parkinson’s disease (PD. Here, we discuss recent developments in the field which have shed light on the role of NO-sGC-cGMP signaling pathways in basal ganglia dysfunction and motor symptoms associated with PD and L-DOPA-induced dyskinesias.

  7. Studies on Relationship between Serum Nitric Oxide and Plasma Cyclic Guanosine Monophosphate and Prolonged Bleeding after Medical Abortion as well as Prophylaxis and Treatment of Bleeding with Traditional Chinese Medicine

    Institute of Scientific and Technical Information of China (English)

    廖玎玲; 谭布珍; 辛华; 贺晓菊

    1999-01-01

    Objectives To study the relationship between serum nitric oxide(NO and plasma cyclic guanosine monophosphate(cGMP)and prolonged bleeding after medical abortion.Methods A total of 120women having received medical abortions at random were recruited and divided into two groups:the one(Group A,n=60) taking “Gong-Fu Mixture(Uterus-Recovering Mixture)”and the other(Group B,n=60)not taking it after abortion.On d 10,20 and 30 after medical abortion,serum NO and plasma cGMP were tested before and after mifepristone administration and 10 d later by Gresis reac-tion method and radioimmunoassay respectively.Results NO concentration in serum and cGMP concentration in plasma decreased signifi-cantly after taking mifeprlstone given(P<0. 05).Ten days later,the number of thos ewith bleeding discontinuation in the group A was significantly greater than that in the group B(P<0.05).Serum NO level and plasma cGMP level in the group A de-creased more significantly than those in the group B(P<0. 05).Conclusion The slow decrease of serum NO and plasma cGMP is closely related to prolonged bleeding after medical abortion.“Gong-Fu Mixture(uterus-recovering mixture)”is effective in prevention and treatment of prolonged bleeding.

  8. Involvement of NMDA receptors and L-arginine/nitric oxide/cyclic guanosine monophosphate pathway in the antidepressant-like effects of topiramate in mice forced swimming test.

    Science.gov (United States)

    Ostadhadi, Sattar; Khan, Muhammad Imran; Norouzi-Javidan, Abbas; Chamanara, Mohsen; Jazaeri, Farahnaz; Zolfaghari, Samira; Dehpour, Ahmad-Reza

    2016-04-01

    Topiramate (TPM) is an agent primarily used in the treatment of epilepsy. Using mice model of forced swimming test (FST) the current study was basically aimed to investigate the influence of TPM on depression by inhibiting NMDA receptor and nitric oxide-cGMP production. When TPM was administered in a dose of 20 and 30 mg/kg by i.p. route it reduced the immobility time during FST. However this effect of TPM (30 mg/kg, i.p.) in the FST was abolished when the mice were pretreated either with NMDA (75 mg/kg, i.p.), or l-arginine (750 mg/kg, i.p. NO precursor), or sildenafil (5mg/kg, i.p. Phosphodiesterase 5 inhibitor). The immobility time in the FST was reduced after administration of L-NAME (10mg/kg, i.p, a non-specific NOS inhibitor), 7-nitoinidazol (30 mg/kg, i.p. a nNOS inhibitor) or MK-801 (0.05 mg/kg, i.p, a NMDA receptor antagonist) in combination with a subeffective dose of TPM (10mg/kg, i.p.) as compared with single use of either drug. Co-administrated of lower doses of MK-801 (0.01 mg/kg) or L-NAME (1mg/kg) failed to effect immobility time. However, simultaneous administration of these two agents in the same doses with subeffective dose of TPM (10mg/kg, i.p.), reduced the immobility time during FST. None of these drugs were found to have a profound effect on the locomotor activity per se during the open field test. Taken together, our data demonstrates that TPM exhibit antidepressant-like effect which is accomplished either due to inhibition of NMDA receptors or NO-cGMP production.

  9. Determination of nitric oxide mediating intracellular Ca2+ release on neurons based on confocal microscopy imaging

    Science.gov (United States)

    Zheng, Liqin; Wang, Yuhua; He, Yipeng; Zeng, Yixiu; Zhang, Yanding; Xie, Shusen

    2014-09-01

    The gas NO is a ubiquitous intercellular messenger that modulates a wide range of physiological and pathophysiological functions. But few studies were made to study the role of NO in the Ca2+ release in dorsal root ganglion (DRG) neurons by confocal microscopy. Thus the objective of this study was to assess if NO has a role in Ca2+ signaling in DRG neurons using confocal microscopy combined with special fluorescence probe Fluo-3/AM. A 100 μM concentration of the NO donors (Sodium Nitroprusside, Dihydrate, SNP) and NO synthase inhibitor (NG-Monomethyl-L-arginine, Monoacetate salt, L-NMMA) was used in the study. Results showed that the fluorescence intensity increased rapidly after injecting SNP, which indicated that SNP could enhance intracellular Ca2+ release. And the fluorescence intensity shrank gradually with time and kept at a low level for quite a long period after loading with L-NMMA which indicated that L-NMMA could block intracellular Ca2+ release. All these results demonstrated that NO was involved in the regulation of intracellular Ca2+ release in the DRG neurons.

  10. Novel approaches to improving endothelium-dependent nitric oxide-mediated vasodilatation

    DEFF Research Database (Denmark)

    Simonsen, Ulf; Rodriguez-Rodriguez, Rosalia; Dalsgaard, Thomas

    2009-01-01

    reacting with NO. Endothelial dysfunction is therapeutically reversible and physical exercise, calcium channel blockers, angiotensin converting enzyme inhibitors, and angiotensin receptor antagonists improve flow-evoked endothelium-dependent vasodilation in patients with hypertension and diabetes. We have...... channels and an influx of calcium play an important role in G-protein coupled receptor-evoked release of NO. Thus, all three approaches increase bioavailability of NO in the vascular wall, but it remains to be addressed whether these actions have any direct benefit at a clinical level....

  11. Nitric oxide mediated Staphylococcus aureus pathogenesis and protective role of nanoconjugated vancomycin

    Institute of Scientific and Technical Information of China (English)

    Subhankari Prasad Chakraborty; Santanu Kar Mahapatra; Sumanta Kumar Sahu; Sourav Chattopadhyay; Panchanan Pramanik; Somenath Roy

    2011-01-01

    Objective:To test the survival ofStaphylococcus aureus (S. aureus) inside lymphocyte that contributes to the pathogenesis of infection and possible anti-inflammatory and antioxidative effect of nanoconjugated vancomycin againstin vivo S. aureus infection in a dose and duration dependent manner.Methods:5×106CFU/mL vancomycin-sensitive S. aureus(VSSA) and vancomycin-resistiveS. aureus (VRSA) were challenged in Swiss male mice for3 days,5 days, 10 days and15days, respectively. Bacteremia and inflammatory parameters were observed to evaluate the duration for development ofVSSA andVRSA infection.100mg/kg bw/day and500 mg/kg bw/day nanoconjugated vancomycin were administrated toVSSA andVRSA infected group for5days. Bacteremia, inflammatory parameters and oxidative stress related parameters were tested to observe the effective dose of nanoconjugated vancomycin againstVSSAandVRSA infection. Nanoconjugated vancomycin was treated at a dose of100 mg/kg bw/day and500 mg/kg bw/day, respectively, toVSSA andVRSA infected group for successive5 days,10 days and 15 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were observed to assess the effective duration of nanoconjugated vancomycin againstVSSAand VRSA infection.Results: The result revealed thatin vivoVSSA andVRSA infection developed after 5 days of challenge by elevating theNO generation in lymphocyte and serum inflammatory markers. Administration with nanoconjugated vancomycin toVSSA andVRSA infected group at a dose of100 mg/kg bw/day and500 mg/kg bw/day, respectively, for successive10 days eliminated bacterimia, decreasedNO generation in lymphocyte, serum inflammatory markers and increased antioxidant enzyme status.Conclusions:These findings suggest,in vivochallenge ofVSSA andVRSA for5 days can produce the highest degree of damage in lymphocyte which can be ameliorated by treatment with nanoconjugated vancomycin for10 successive days.

  12. Infrared Imaging of Nitric Oxide-Mediated Blood Flow in Human Sickle Cell Disease

    Science.gov (United States)

    Gorbach, Alexander M.; Ackerman, Hans C.; Liu, Wei-Min; Meyer, Joseph M.; Littel, Patricia L.; Seamon, Catherine; Footman, Eleni; Chi, Amy; Zorca, Suzana; Krajewski, Megan L.; Cuttica, Michael J.; Machado, Roberto F.; Cannon, Richard O.; Kato, Gregory J.

    2012-01-01

    Vascular dysfunction is an important pathophysiologic manifestation of sickle cell disease (SCD), a condition that increases risk of pulmonary hypertension and stroke. We hypothesized that infrared (IR) imaging would detect changes in cutaneous blood flow reflective of vascular function. We performed IR imaging and conventional strain gauge plethysmography in twenty-five adults with SCD at baseline and during intra-arterial infusions of an endothelium-dependent vasodilator acetylcholine (ACh), an endothelium-independent vasodilator sodium nitroprusside (SNP), and a NOS inhibitor L-NMMA. Skin temperature measured by IR imaging increased in a dose-dependent manner to graded infusions of ACh (+1.1° C, p < 0.0001) and SNP (+0.9° C, p < 0.0001), and correlated with dose-dependent increases in forearm blood flow (ACh: +19.9 mL/min/100mL, p < 0.0001; rs = 0.57, p = 0.003; SNP: +8.6 mL/min/100mL, p < 0.0001; r = 0.70, p = 0.0002). Although IR measurement of skin temperature accurately reflected agonist-induced increases in blood flow, it was less sensitive to decreases in blood flow caused by NOS inhibition. Baseline forearm skin temperature measured by IR imaging correlated significantly with baseline forearm blood flow (31.8±0.2° C, 6.0±0.4 mL/min/100mL; r = 0.58, p = 0.003), and appeared to represent a novel biomarker of vascular function. It predicted a blunted blood flow response to SNP (r = −0.61, p = 0.002), and was independently associated with a marker of pulmonary artery pressure, as well as hemoglobin level, diastolic blood pressure, homocysteine, and cholesterol (R2 = 0.84, p < 0.0001 for the model). IR imaging of agonist-stimulated cutaneous blood flow represents a less cumbersome alternative to plethysmography methodology. Measurement of baseline skin temperature by IR imaging may be a useful new marker of vascular risk in adults with SCD. PMID:22784510

  13. The Development Of RRx-001, A Novel Nitric-Oxide-Mediated Epigenetically Active Anticancer Agent

    Directory of Open Access Journals (Sweden)

    Jan Scicinski

    2015-08-01

    Conclusion: Early results in the ROCKET study suggest that RRx-001-mediated resensitization to previously refractory therapies may have a generalized effect, independent of KRAS or p53 status. These early results are intriguing, suggesting improved QOL and overall survival over currently approved therapy in the chemotherapy refractory colorectal cancer.

  14. Immune-relevant thrombocytes of common carp undergo parasite-induced nitric oxide-mediated apoptosis

    NARCIS (Netherlands)

    Fink, I.R.; Ribeiro, C.M.S.; Forlenza, M.; Taverne-Thiele, J.J.; Rombout, J.H.W.M.; Savelkoul, H.F.J.; Wiegertjes, G.

    2015-01-01

    Common carp thrombocytes account for 30–40% of peripheral blood leukocytes and are abundant in the healthy animals' spleen, the thrombopoietic organ. We show that, ex vivo, thrombocytes from healthy carp express a large number of immune-relevant genes, among which several cytokines and Toll-like rec

  15. [Nitric oxide].

    Science.gov (United States)

    Rovira, I

    1995-01-01

    Nitric oxide was identified as the relaxing factor derived from the endothelium in 1987. Nitric oxide synthesis allows the vascular system to maintain a state of vasodilation, thereby regulating arterial pressure. Nitric oxide is also found in platelets, where it inhibits adhesion and aggregation; in the immune system, where it is responsible for the cytotoxic action of macrophages; and in the nervous system, where it acts as neurotransmitter. A deficit in endogenous synthesis of nitric oxide contributes to such conditions as essential arterial hypertension, pulmonary hypertension and heart disease. An excess of nitrous oxide induced by endotoxins and cytokinins, meanwhile, is believed to be responsible for hypotension in septic shock and for hyperdynamic circulatory state in cirrhosis of the liver. Nitric oxide has also been implicated in the rejection of transplanted organs and in cell damage after reperfusion. Inhaled nitrous oxide gas reduces pulmonary hypertension without triggering systemic hypotension in both experimental and clinical conditions. It also produces selective vasodilation when used to ventilate specific pulmonary areas, thereby improving the ventilation/perfusion ratio and, hence, oxygenation. Nitric oxide inhalation is effective in pulmonary hypertension-coincident with chronic obstructive lung disease, in persistent neonatal pulmonary hypertension and in pulmonary hypertension with congenital or acquired heart disease. Likewise, it reduces intrapulmonary shunt in acute respiratory failure and improves gas exchange. Under experimental conditions nitric oxide acts as a bronchodilator, although it seems to be less effective for this purpose in clinical use.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Electrochemical Behavior of Aluminum in Nitric Acid

    Institute of Scientific and Technical Information of China (English)

    CHEN; Hui; ZHU; Li-yang; LIN; Ru-shan; TAN; Hong-bin; HE; Hui

    2013-01-01

    Aluminum is one of cladding materials for nuclear fuel,it is important to investigate the electrolytic dissolution of aluminum in nitric acid.The electrochemical impedance spectroscopy,polarization curve and cyclic voltammetry cure of anodic aluminum electrode in nitric acid under various conditions were collected(Fig.1).It turns out,under steady state,the thickness of the passivated film of aluminum

  17. Cyclic derangements

    CERN Document Server

    Assaf, Sami H

    2010-01-01

    A classic problem in enumerative combinatorics is to count the number of derangements, that is, permutations with no fixed point. Inspired by a recent generalization to facet derangements of the hypercube by Gordon and McMahon, we generalize this problem to enumerating derangements in the wreath product of any finite cyclic group with the symmetric group. We also give q- and (q, t)-analogs for cyclic derangements, generalizing results of Brenti and Gessel.

  18. Cyclic Voltammetry.

    Science.gov (United States)

    Evans, Dennis H.; And Others

    1983-01-01

    Cyclic voltammetry is a simple experiment that has become popular in chemical research because it can provide useful information about redox reactions in a form which is easily obtained and interpreted. Discusses principles of the method and illustrates its use in the study of four electrode reactions. (Author/JN)

  19. Cyclic Voltammetry.

    Science.gov (United States)

    Evans, Dennis H.; And Others

    1983-01-01

    Cyclic voltammetry is a simple experiment that has become popular in chemical research because it can provide useful information about redox reactions in a form which is easily obtained and interpreted. Discusses principles of the method and illustrates its use in the study of four electrode reactions. (Author/JN)

  20. Cyclic multiverses

    CERN Document Server

    Marosek, Konrad; Balcerzak, Adam

    2015-01-01

    Starting with the idea of regularization of singularities due to the variability of the fundamental constants in cosmology we first study the cyclic universe models. We find two models of oscillating mass density and pressure regularized by varying gravitational constant $G$. Then, we extend this idea onto the multiverse containing cyclic individual universes with either growing or decreasing entropy though leaving the net entropy constant. In order to get the key idea, we consider the doubleverse with the same geometrical evolution of the two "parallel" universes with their physical evolution (physical coupling constants $c(t)$ and $G(t)$) being different. An interesting point is that there is a possibility to exchange the universes at the point of maximum expansion -- the fact which was already noticed in quantum cosmology. Similar scenario is also possible within the framework of Brans-Dicke theory.

  1. Supplementary Material for: The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-01-01

    Abstract Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  2. Cyclic Vitalism

    DEFF Research Database (Denmark)

    Halse, Sven

    2014-01-01

    an enthusiastic worshipping of life, one that holds youth, health, strength and beauty as its primary attributes, and which was prevalent in all aspects of cultural life around 1900. But even the post war founders of the Vitalist re-conceptualisation of this era, Wolfdietrich Rasch and Gunter Martens, warned...... that also encompasses notions of destruction, decay and death. “All life symbols in literature around 1900 are at the same time symbols of death”. (Rasch, W. 1967:24) Through the analyses of three poems, this article aims to show concrete examples of how cyclic Vitalist thinking is embedded in poetry...

  3. Cyclic multiverses

    Science.gov (United States)

    Marosek, Konrad; Dąbrowski, Mariusz P.; Balcerzak, Adam

    2016-09-01

    Using the idea of regularization of singularities due to the variability of the fundamental constants in cosmology we study the cyclic universe models. We find two models of oscillating and non-singular mass density and pressure (`non-singular' bounce) regularized by varying gravitational constant G despite the scale factor evolution is oscillating and having sharp turning points (`singular' bounce). Both violating (big-bang) and non-violating (phantom) null energy condition models appear. Then, we extend this idea on to the multiverse containing cyclic individual universes with either growing or decreasing entropy though leaving the net entropy constant. In order to get an insight into the key idea, we consider the doubleverse with the same geometrical evolution of the two `parallel' universes with their physical evolution [physical coupling constants c(t) and G(t)] being different. An interesting point is that there is a possibility to exchange the universes at the point of maximum expansion - the fact which was already noticed in quantum cosmology. Similar scenario is also possible within the framework of Brans-Dicke theory where varying G(t) is replaced by the dynamical Brans-Dicke field φ(t) though these theories are slightly different.

  4. Maternal smoking and impaired endothelium-dependent nitric oxide-mediated relaxation of uterine small arteries in vitro

    DEFF Research Database (Denmark)

    Andersen, Malene R; Uldbjerg, Niels; Stender, Steen;

    2011-01-01

    This study aimed to investigate the endothelium-dependent relaxation of uterine small arteries from pregnant nonsmokers, smokers, and ex-smokers who stopped smoking early in pregnancy.......This study aimed to investigate the endothelium-dependent relaxation of uterine small arteries from pregnant nonsmokers, smokers, and ex-smokers who stopped smoking early in pregnancy....

  5. Modulatory role of nitric oxide in cardiac performance

    Directory of Open Access Journals (Sweden)

    Smiljić Sonja

    2014-01-01

    Full Text Available Nitric oxide is produced by almost all cardiac cells, endothelial cells, cardiomyocytes and nerve fibers. It is synthesized by an enzyme, a nitric oxide synthase, which occurs in endothelial, neural and inducible form. The distribution of nitric oxide synthase in the heart is characterized by a pronounced non-uniformity. Nitric oxide exerts its effects in physiological and pathophysiological conditions. The physiological effects of low concentrations of nitric oxide, which is released in the normal conditions under the influence of constituent enzymes, occur via cyclic guanosine monophosphate. The synthesized nitric oxide exhibits its effect in the cells where it is produced, in an autocrine manner, or by diffusing into the neighboring cells, in a paracrine manner. Nitric oxide acts by regulating the coronary vessel tonus, affecting the contractility of cardiomyocytes, generating an inotropic effect in a dose-dependent manner and controlling the cellular respiration. Other effects of nitric oxide in the cardiovascular system include the hyperpolarization of the smooth muscle cells in blood vessels, the inhibition of the monocyte adhesion, the inhibition of platelet migration, adhesion and aggregation and the proliferation of smooth muscle cells and fibroblasts. The anti-atherosclerotic effects of nitric oxide are based on these effects. Nitric oxide is a weak free radical in gaseous state, and the cytotoxic and/or the cytoprotective effects of the higher concentrations of nitric oxide are related to the chemical structure of nitric oxide as a free radical. The excessive production of nitric oxide by the activation of inducible nitric oxide synthase can lead to major irregularities in the function of cardiomyocytes and cardiac insufficiency. Understanding the nitric oxide molecular mechanisms of signaling pathways in the heart can provide a new strategic approach to prevention and treatment of cardiovascular diseases.

  6. Nitric oxide promotes survival of cerebellar granule neurons cultured in vitro through the Akt pathway

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Mei Li; Lihua Zhou

    2011-01-01

    In this study, cerebellar granule neurons were used to examine the role of nitric oxide on cell survival. The N-methyl-D-aspartic acid receptor antagonist, MK-801, and the soluble guanylate cyclase antagonist, 1H-[1, 2, 4]oxadiazolo-[4, 3-a] quinoxalin-1-one, decreased cell viability, induced caspase-3, and decreased phosphorylated-Akt levels, suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons. After administration of sodium nitroprusside, an endogenous nitric oxide donor, cell viability recovered,caspase-3 expression was decreased, and phosphorylated-Akt levels increased. This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway. Moreover, endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.

  7. Cyclic Vitalism

    DEFF Research Database (Denmark)

    Halse, Sven

    2014-01-01

    of taking such a unilateral view of what constituted a Vitalist concept of life. It could lead to a misunderstanding of Vitalist way of thinking, Rasch said, if the focus were only set upon the enthusiastic surplus, the worshipping of youth and health. To Vitalists, life is more than that. It is a totality...... that also encompasses notions of destruction, decay and death. “All life symbols in literature around 1900 are at the same time symbols of death”. (Rasch, W. 1967:24) Through the analyses of three poems, this article aims to show concrete examples of how cyclic Vitalist thinking is embedded in poetry...... of the era. The analyses include a further sub-categorisation to capture the different types of Life Force dealt with in the texts. By way of an introduction, Vitalism is discussed within the context of the scientific and social developments of the 19th Century....

  8. Multifaceted role of nitric oxide in an in vitro mouse neuronal injury model: transcriptomic profiling defines the temporal recruitment of death signalling cascades

    Science.gov (United States)

    Peng, Zhao Feng; Chen, Minghui Jessica; Manikandan, Jayapal; Melendez, Alirio J; Shui, Guanghou; Russo-Marie, Françoise; Whiteman, Matthew; Beart, Philip M; Moore, Philip K; Cheung, Nam Sang

    2012-01-01

    Abstract Nitric oxide is implicated in the pathogenesis of various neuropathologies characterized by oxidative stress. Although nitric oxide has been reported to be involved in the exacerbation of oxidative stress observed in several neuropathologies, existent data fail to provide a holistic description of how nitrergic pathobiology elicits neuronal injury. Here we provide a comprehensive description of mechanisms contributing to nitric oxide induced neuronal injury by global transcriptomic profiling. Microarray analyses were undertaken on RNA from murine primary cortical neurons treated with the nitric oxide generator DETA-NONOate (NOC-18, 0.5 mM) for 8–24 hrs. Biological pathway analysis focused upon 3672 gene probes which demonstrated at least a ±1.5-fold expression in a minimum of one out of three time-points and passed statistical analysis (one-way anova, P < 0.05). Numerous enriched processes potentially determining nitric oxide mediated neuronal injury were identified from the transcriptomic profile: cell death, developmental growth and survival, cell cycle, calcium ion homeostasis, endoplasmic reticulum stress, oxidative stress, mitochondrial homeostasis, ubiquitin-mediated proteolysis, and GSH and nitric oxide metabolism. Our detailed time-course study of nitric oxide induced neuronal injury allowed us to provide the first time a holistic description of the temporal sequence of cellular events contributing to nitrergic injury. These data form a foundation for the development of screening platforms and define targets for intervention in nitric oxide neuropathologies where nitric oxide mediated injury is causative. PMID:21352476

  9. Nitric oxide: considerations for the treatment of ischemic stroke

    Science.gov (United States)

    Terpolilli, Nicole A; Moskowitz, Michael A; Plesnila, Nikolaus

    2012-01-01

    Some 40 years ago it was recognized by Furchgott and colleagues that the endothelium releases a vasodilator, endothelium-derived relaxing factor (EDRF). Later on, several groups identified EDRF to be a gas, nitric oxide (NO). Since then, NO was identified as one of the most versatile and unique molecules in animal and human biology. Nitric oxide mediates a plethora of physiological functions, for example, maintenance of vascular tone and inflammation. Apart from these physiological functions, NO is also involved in the pathophysiology of various disorders, specifically those in which regulation of blood flow and inflammation has a key role. The aim of the current review is to summarize the role of NO in cerebral ischemia, the most common cause of stroke. PMID:22333622

  10. High-intensity interval training prevents oxidant-mediated diaphragm muscle weakness in hypertensive mice.

    Science.gov (United States)

    Bowen, T Scott; Eisenkolb, Sophia; Drobner, Juliane; Fischer, Tina; Werner, Sarah; Linke, Axel; Mangner, Norman; Schuler, Gerhard; Adams, Volker

    2017-01-01

    Hypertension is a key risk factor for heart failure, with the latter characterized by diaphragm muscle weakness that is mediated in part by increased oxidative stress. In the present study, we used a deoxycorticosterone acetate (DOCA)-salt mouse model to determine whether hypertension could independently induce diaphragm dysfunction and further investigated the effects of high-intensity interval training (HIIT). Sham-treated (n = 11), DOCA-salt-treated (n = 11), and DOCA-salt+HIIT-treated (n = 15) mice were studied over 4 wk. Diaphragm contractile function, protein expression, enzyme activity, and fiber cross-sectional area and type were subsequently determined. Elevated blood pressure confirmed hypertension in DOCA-salt mice independent of HIIT (P HIIT. Myosin heavy chain (MyHC) protein expression tended to decrease (∼30%; P = 0.06) in DOCA-salt vs. sham- and DOCA-salt+HIIT mice, whereas oxidative stress increased (P HIIT further prevented direct oxidant-mediated diaphragm contractile dysfunction (P HIIT.-Bowen, T. S., Eisenkolb, S., Drobner, J., Fischer, T., Werner, S., Linke, A., Mangner, N., Schuler, G., Adams, V. High-intensity interval training prevents oxidant-mediated diaphragm muscle weakness in hypertensive mice.

  11. Cyclic Vomiting Syndrome

    Science.gov (United States)

    ... or the flu eating certain foods, such as chocolate or cheese, or additives such as caffeine, nitrites— ... people with cyclic vomiting syndrome. Eating, Diet, and Nutrition During the prodrome and vomiting phases of cyclic ...

  12. Superextensions of cyclic semigroups

    Directory of Open Access Journals (Sweden)

    V. M. Gavrylkiv

    2013-06-01

    Full Text Available Given a cyclic semigroup $S$ we study right and left zeros,singleton left ideals, the minimal ideal, left cancelable andright cancelable elements of superextensions $lambda(S$ andcharacterize cyclic semigroups whose superextensions arecommutative.

  13. NITRIC OXIDE SYNTHESIS IN MYOCARDIUM FOLLOWING BURN INJURY IN RATS

    Institute of Scientific and Technical Information of China (English)

    王卫东; 陈宗荣; 李蓉; 楼淑芳

    1998-01-01

    The nitric oxide and cyclic GMP production in myocardium early after burn injury in tats were investigated. Nitric oxide synthase activity was measured in cytosols from the left ventricular wall of burned rats.Cytosols from the control group animals were shown to contain mainly Ca2+ dependent nitric oxide synthase (cNOS) with small amount of Ca2+ independent nitric oxide synthase (iNOS). Following burn injury,there was a marked increase in iNOS activity with a peak at 8h post-butyl, however, myocardial cNOS activity was found to decline obviously. Parallel to iNOS induction there was a significant increase in myocardial nitric oxide and cyelic GMP production. All these chenges were alleviated by treatment of the rats with dexamethasone. Since increases in cyclic GMP levels in the heart were associated with reduced myocardial contractility, it is possible that enhanced production of nitric oxide by a Ca2+ independent NO synthase accounts, at least in part, for the depression of myocardial contractility seen in burn animals and patients.

  14. Cyclic Railway Timetable Optimization

    NARCIS (Netherlands)

    L.W.P. Peeters (Leon)

    2003-01-01

    textabstractCyclic Railway Timetable Optimization describes mathematical models and solution methods for constructing high quality cyclic railway timetables. In a cyclic timetable, a train for a certain destination leaves a certain station at the same time every cycle time, say every half an hour,

  15. Cyclic Nucleotide Signalling in Kidney Fibrosis

    Directory of Open Access Journals (Sweden)

    Elisabeth Schinner

    2015-01-01

    Full Text Available Kidney fibrosis is an important factor for the progression of kidney diseases, e.g., diabetes mellitus induced kidney failure, glomerulosclerosis and nephritis resulting in chronic kidney disease or end-stage renal disease. Cyclic adenosine monophosphate (cAMP and cyclic guanosine monophosphate (cGMP were implicated to suppress several of the above mentioned renal diseases. In this review article, identified effects and mechanisms of cGMP and cAMP regarding renal fibrosis are summarized. These mechanisms include several signalling pathways of nitric oxide/ANP/guanylyl cyclases/cGMP-dependent protein kinase and cAMP/Epac/adenylyl cyclases/cAMP-dependent protein kinase. Furthermore, diverse possible drugs activating these pathways are discussed. From these diverse mechanisms it is expected that new pharmacological treatments will evolve for the therapy or even prevention of kidney failure.

  16. Cyclic phosphonium ionic liquids

    Directory of Open Access Journals (Sweden)

    Sharon I. Lall-Ramnarine

    2014-01-01

    Full Text Available Ionic liquids (ILs incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonylamide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners.

  17. Nitric oxide supersensitivity

    DEFF Research Database (Denmark)

    Olesen, J; Iversen, Helle Klingenberg; Thomsen, L L

    1993-01-01

    in a double blind design to 17 migraine patients, 17 age and sex matched healthy controls and 9 subjects with tension-type headache. The nitroglycerin-induced headache was significantly more severe in migraine sufferers, lasted longer and fulfilled diagnostic criteria for migraine more often. We have...... previously shown a similar supersensitivity to histamine which in human cerebral arteries activates endothelial H1 receptors and causes endothelial production of nitric oxide. Migraine patients are thus supersensitive to exogenous nitric oxide from nitroglycerin as well as to endothelially produced nitric...

  18. Affordable Cyclic Voltammetry

    Science.gov (United States)

    Stewart, Greg; Kuntzleman, Thomas S.; Amend, John R.; Collins, Michael J.

    2009-01-01

    Cyclic voltammetry is an important component of the undergraduate chemical curriculum. Unfortunately, undergraduate students rarely have the opportunity to conduct experiments in cyclic voltammetry owing to the high cost of potentiostats, which are required to control these experiments. By using MicroLab data acquisition interfaces in conjunction…

  19. Affordable Cyclic Voltammetry

    Science.gov (United States)

    Stewart, Greg; Kuntzleman, Thomas S.; Amend, John R.; Collins, Michael J.

    2009-01-01

    Cyclic voltammetry is an important component of the undergraduate chemical curriculum. Unfortunately, undergraduate students rarely have the opportunity to conduct experiments in cyclic voltammetry owing to the high cost of potentiostats, which are required to control these experiments. By using MicroLab data acquisition interfaces in conjunction…

  20. Cyclic anamorphic cosmology

    CERN Document Server

    Ijjas, Anna

    2016-01-01

    Cyclic models of the universe have the advantage of avoiding initial conditions problems related to postulating any sort of beginning in time. To date, the only known viable examples of cyclic models have been ekpyrotic. In this paper, we show that the recently proposed anamorphic scenario can also be made cyclic. The key to the cyclic completion is a classically stable, non-singular bounce. Remarkably, even though the bounce construction was originally developed to connect a period of contraction with a period of expansion both described by Einstein gravity, we show here that it can naturally be modified to connect an ordinary contracting phase described by Einstein gravity with a phase of anamorphic smoothing. The paper will present the basic principles and steps in constructing cyclic anamorphic models.

  1. Real Topological Cyclic Homology

    DEFF Research Database (Denmark)

    Høgenhaven, Amalie

    The main topics of this thesis are real topological Hochschild homology and real topological cyclic homology. If a ring or a ring spectrum is equipped with an anti-involution, then it induces additional structure on the topological Hochschild homology spectrum. The group O(2) acts on the spectrum......, where O(2) is the semi-direct product of T, the multiplicative group of complex number of modulus 1, by the group G=Gal(C/R). We refer to this O(2)-spectrum as the real topological Hochschild homology. This generalization leads to a G-equivariant version of topological cyclic homology, which we call...... real topological cyclic homology. The first part of the thesis computes the G-equivariant homotopy type of the real topological cyclic homology of spherical group rings at a prime p with anti-involution induced by taking inverses in the group. The second part of the thesis investigates the derived G...

  2. Spectroscopic and electrical sensing mechanism in oxidant-mediated polypyrrole nanofibers/nanoparticles for ammonia gas

    Science.gov (United States)

    Ishpal; Kaur, Amarjeet

    2013-05-01

    Ammonia gas sensing mechanism in oxidant-mediated polypyrrole (PPy) nanofibers/nanoparticles has been studied through spectroscopic and electrical investigations. PPy nanofibers/nanoparticles have been synthesized by chemical oxidation method in the presence of various oxidizing agents such as ammonium persulfate (APS), potassium persulfate (PPS), vanadium pentoxide (V2O5), and iron chloride (FeCl3). Scanning electron microscopy study revealed that PPy nanofibers of about 63, 71 and 79 nm diameters were formed in the presence of APS, PPS, V2O5, respectively, while PPy nanoparticles of about 100-110 nm size were obtained in the presence of FeCl3 as an oxidant. The structural investigations and confirmation of synthesis of PPy were established through Fourier transform infrared and Raman spectroscopy. The gas sensing behavior of the prepared PPy samples is investigated by measuring the electrical resistance in ammonia environment. The observed gas sensing response ( δR R × 100 ) at 100 ppm level of ammonia is 4.5 and 18 % for the samples prepared with oxidizing agents FeCl3 and APS, respectively, and by changing the ammonia level from 50 to 300 ppm, the sensing response varies from 4.5 to 11 % and 10 to 39 %, respectively. Out of all four samples, the PPy nanofibers prepared in the presence of APS have shown the best sensing response. The mechanism of gas sensing response of the PPy samples has been investigated through Raman spectroscopy study. The decrease of charge carrier concentration through reduction of polymeric chains has been recognized through Raman spectroscopic measurements recorded in ammonia environment.

  3. Spectroscopic and electrical sensing mechanism in oxidant-mediated polypyrrole nanofibers/nanoparticles for ammonia gas

    Energy Technology Data Exchange (ETDEWEB)

    Ishpal; Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [University of Delhi, Department of Physics and Astrophysics (India)

    2013-05-15

    Ammonia gas sensing mechanism in oxidant-mediated polypyrrole (PPy) nanofibers/nanoparticles has been studied through spectroscopic and electrical investigations. PPy nanofibers/nanoparticles have been synthesized by chemical oxidation method in the presence of various oxidizing agents such as ammonium persulfate (APS), potassium persulfate (PPS), vanadium pentoxide (V{sub 2}O{sub 5}), and iron chloride (FeCl{sub 3}). Scanning electron microscopy study revealed that PPy nanofibers of about 63, 71 and 79 nm diameters were formed in the presence of APS, PPS, V{sub 2}O{sub 5}, respectively, while PPy nanoparticles of about 100-110 nm size were obtained in the presence of FeCl{sub 3} as an oxidant. The structural investigations and confirmation of synthesis of PPy were established through Fourier transform infrared and Raman spectroscopy. The gas sensing behavior of the prepared PPy samples is investigated by measuring the electrical resistance in ammonia environment. The observed gas sensing response ({Delta}R/Rx100) at 100 ppm level of ammonia is {approx}4.5 and 18 % for the samples prepared with oxidizing agents FeCl{sub 3} and APS, respectively, and by changing the ammonia level from 50 to 300 ppm, the sensing response varies from {approx}4.5 to 11 % and {approx}10 to 39 %, respectively. Out of all four samples, the PPy nanofibers prepared in the presence of APS have shown the best sensing response. The mechanism of gas sensing response of the PPy samples has been investigated through Raman spectroscopy study. The decrease of charge carrier concentration through reduction of polymeric chains has been recognized through Raman spectroscopic measurements recorded in ammonia environment.

  4. Mechanistic Variants in Gas-Phase Metal-Oxide Mediated Activation of Methane at Ambient Conditions.

    Science.gov (United States)

    Li, Jilai; Zhou, Shaodong; Zhang, Jun; Schlangen, Maria; Usharani, Dandamudi; Shaik, Sason; Schwarz, Helmut

    2016-09-07

    The C-H bond activation of methane mediated by a prototypical heteronuclear metal-oxide cluster, [Al2Mg2O5](•+), was investigated by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in conjunction with high-level quantum mechanical calculations. Experimentally, hydrogen-atom abstraction from methane by the cluster ion [Al2Mg2O5](•+) takes place at ambient conditions. As to the mechanism, according to our computational findings, both the proton-coupled electron transfer (PCET) and the conventional hydrogen-atom transfer (HAT) are feasible and compete with each other. This is in distinct contrast to the [XYO2](+) (X, Y = Mg, Al, Si) cluster oxide ions which activate methane exclusively via the PCET route (Li, J.; Zhou, S.; Zhang, J.; Schlangen, M.; Weiske, T.; Usharani, D.; Shaik, S.; Schwarz, H. J. Am. Chem. Soc. 2016, 138, 7973-7981). The electronic origins of the mechanistically rather complex reactivity scenarios of the [Al2Mg2O5](•+)/CH4 couple were elucidated. For the PCET mechanism, in which the Lewis acid-base pair [Al(+)-O(-)] of the cluster acts as the active site, a clear correlation has been established between the nature of the transition state, the corresponding barrier height, the Lewis acidity-basicity of the [M(+)-O(-)] unit, as well as the bond order of the M(+)-O(-) bond. Also addressed is the role of the spin and charge distributions of a terminal oxygen radical site in the direct HAT route. The knowledge of the factors that control the reactivity of PCET and HAT pathways not only deepens our mechanistic understanding of metal-oxide mediated C-H bond activation but may also provide guidance for the rational design of catalysts.

  5. Cup products in Hopf cyclic cohomology via cyclic modules I

    CERN Document Server

    Rangipour, Bahram

    2007-01-01

    This is the first one in a series of two papers on the continuation of our study in cup products in Hopf cyclic cohomology. In this note we construct cyclic cocycles of algebras out of Hopf cyclic cocycles of algebras and coalgebras. In the next paper we consider producing Hopf cyclic cocycle from "equivariant" Hopf cyclic cocycles. Our approach in both situations is based on (co)cyclic modules and bi(co)cyclic modules together with Eilenberg-Zilber theorem which is different from the old definition of cup products defined via traces and cotraces on DG algebras and coalgebras.

  6. Cyclic polymers from alkynes

    Science.gov (United States)

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  7. Dispersal of human and plant pathogens biofilms via nitric oxide donors at 4 °C.

    Science.gov (United States)

    Marvasi, Massimiliano; Durie, Ian A; Henríquez, Tania; Satkute, Aiste; Matuszewska, Marta; Prado, Raphael Carvalho

    2016-12-01

    Recent studies suggest that nitric oxide donors capable of manipulating nitric oxide-mediated signaling in bacteria could induce dispersal of biofilms. Encased in extracellular polymeric substances, human and plant pathogens within biofilms are significantly more resistant to sanitizers. This is particularly a problem in refrigerated environments where food is processed. In an exercise aimed to study the potential of nitric oxide donors as biofilm dispersal in refrigerated conditions, we compared the ability of different nitric oxide donors (SNAP, NO-aspirin and Noc-5) to dislodge biofilms formed by foodborne, human and plant pathogens treated at 4 °C. The donors SNAP and Noc-5 were efficient in dispersing biofilms formed by Salmonella enterica, pathogenic Escherichia coli and Listeria innocua. The biomasses were decreased up to 30 % when compared with the untreated controls. When the plant pathogens Pectobacterium sp. and Xanthomonas sp. were tested the dispersion was mainly limited to Pectobacterium carotovorum biofilms, decreasing up to 15 % after exposure to molsidomine. Finally, the association of selected nitric oxide donors with sanitizers (DiQuat, H2O2, peracetic acid and PhenoTek II) was effective in dispersing biofilms. The best dispersal was achieved by pre-treating P. carotovorum with molsidomine and then peracetic acid. The synergistic effect was estimated up to ~35 % in dispersal when compared with peracetic acid alone. The association of nitric oxide donors with sanitizers could provide a foundation for an improved sanitization procedure for cleaning refrigerate environments.

  8. Generalized Wideband Cyclic MUSIC

    Directory of Open Access Journals (Sweden)

    Zhang-Meng Liu

    2009-01-01

    Full Text Available The method of Spectral Correlation-Signal Subspace Fitting (SC-SSF fails to separate wideband cyclostationary signals with coherent second-order cyclic statistics (SOCS. Averaged Cyclic MUSIC (ACM method made up for the drawback to some degree via temporally averaging the cyclic cross-correlation of the array output. This paper interprets ACM from another perspective and proposes a new DOA estimation method by generalizing ACM for wideband cyclostationary signals. The proposed method successfully makes up for the aforementioned drawback of SC-SSF and obtains a more satisfying performance than ACM. It is also demonstrated that ACM is a simplified form of the proposed method when only a single spectral frequency is exploited, and the integration of the frequencies within the signal bandwidth helps the new method to outperform ACM.

  9. The cyclic reduction algorithm

    Science.gov (United States)

    Bini, Dario; Meini, Beatrice

    2009-05-01

    Cyclic reduction is an algorithm invented by G.H. Golub and R. W. Hockney in the mid 1960s for solving linear systems related to the finite differences discretization of the Poisson equation over a rectangle. Among the algorithms of Gene Golub, it is one of the most versatile and powerful ever created. Recently, it has been applied to solve different problems from different applicative areas. In this paper we survey the main features of cyclic reduction, relate it to properties of analytic functions, recall its extension to solving more general finite and infinite linear systems, and different kinds of nonlinear matrix equations, including algebraic Riccati equations, with applications to Markov chains, queueing models and transport theory. Some new results concerning the convergence properties of cyclic reduction and its applicability are proved under very weak assumptions. New formulae for overcoming breakdown are provided.

  10. Vascular nitric oxide and superoxide anion contribute to sex-specific programmed cardiovascular physiology in mice.

    Science.gov (United States)

    Roghair, Robert D; Segar, Jeffrey L; Volk, Kenneth A; Chapleau, Mark W; Dallas, Lindsay M; Sorenson, Anna R; Scholz, Thomas D; Lamb, Fred S

    2009-03-01

    Intrauterine environmental pertubations have been linked to the development of adult hypertension. We sought to evaluate the interrelated roles of sex, nitric oxide, and reactive oxygen species (ROS) in programmed cardiovascular disease. Programming was induced in mice by maternal dietary intervention (DI; partial substitution of protein with carbohydrates and fat) or carbenoxolone administration (CX, to increase fetal glucocorticoid exposure). Adult blood pressure and locomotor activity were recorded by radiotelemetry at baseline, after a week of high salt, and after a week of high salt plus nitric oxide synthase inhibition (by l-NAME). In male offspring, DI or CX programmed an elevation in blood pressure that was exacerbated by N(omega)-nitro-l-arginine methyl ester administration, but not high salt alone. Mesenteric resistance vessels from DI male offspring displayed impaired vasorelaxation to ACh and nitroprusside, which was blocked by catalase and superoxide dismutase. CX-exposed females were normotensive, while DI females had nitric oxide synthase-dependent hypotension and enhanced mesenteric dilation. Despite the disparate cardiovascular phenotypes, both male and female DI offspring displayed increases in locomotor activity and aortic superoxide production. Despite dissimilar blood pressures, DI and CX-exposed females had reductions in cardiac baroreflex sensitivity. In conclusion, both maternal malnutrition and fetal glucocorticoid exposure program increases in arterial pressure in male but not female offspring. While maternal DI increased both superoxide-mediated vasoconstriction and nitric oxide mediated vasodilation, the balance of these factors favored the development of hypertension in males and hypotension in females.

  11. A novel soluble immune-type receptor (SITR in teleost fish: carp SITR is involved in the nitric oxide-mediated response to a protozoan parasite.

    Directory of Open Access Journals (Sweden)

    Carla M S Ribeiro

    Full Text Available BACKGROUND: The innate immune system relies upon a wide range of germ-line encoded receptors including a large number of immunoglobulin superfamily (IgSF receptors. Different Ig-like immune receptor families have been reported in mammals, birds, amphibians and fish. Most innate immune receptors of the IgSF are type I transmembrane proteins containing one or more extracellular Ig-like domains and their regulation of effector functions is mediated intracellularly by distinct stimulatory or inhibitory pathways. METHODOLOGY/PRINCIPAL FINDINGS: Carp SITR was found in a substracted cDNA repertoire from carp macrophages, enriched for genes up-regulated in response to the protozoan parasite Trypanoplasma borreli. Carp SITR is a type I protein with two extracellular Ig domains in a unique organisation of a N-proximal V/C2 (or I- type and a C-proximal V-type Ig domain, devoid of a transmembrane domain or any intracytoplasmic signalling motif. The carp SITR C-proximal V-type Ig domain, in particular, has a close sequence similarity and conserved structural characteristics to the mammalian CD300 molecules. By generating an anti-SITR antibody we could show that SITR protein expression was restricted to cells of the myeloid lineage. Carp SITR is abundantly expressed in macrophages and is secreted upon in vitro stimulation with the protozoan parasite T. borreli. Secretion of SITR protein during in vivo T. borreli infection suggests a role for this IgSF receptor in the host response to this protozoan parasite. Overexpression of carp SITR in mouse macrophages and knock-down of SITR protein expression in carp macrophages, using morpholino antisense technology, provided evidence for the involvement of carp SITR in the parasite-induced NO production. CONCLUSION/SIGNIFICANCE: We report the structural and functional characterization of a novel soluble immune-type receptor (SITR in a teleost fish and propose a role for carp SITR in the NO-mediated response to a protozoan parasite.

  12. Inhibition of nuclear factor-kappaB or Bax prevents endoplasmic reticulum stress- but not nitric oxide-mediated apoptosis in INS-1E cells

    DEFF Research Database (Denmark)

    Tonnesen, Morten F; Grunnet, Lars G; Friberg, Josefine

    2009-01-01

    and alternative splicing of the transcription factor Xbp-1 were exclusively activated by TG. TG exposure caused NFkappaB activation, as assessed by IkappaB degradation and NFkappaB DNA binding. Inhibition of NFkappaB or the Bcl-2 family member Bax pathways protected beta-cells against TG- but not SNAP....... Exposure of INS-1E cells to TG or SNAP caused caspase-3 cleavage and apoptosis. Both TG and SNAP induced activation of the proapoptotic transcription factor CCAAT/enhancer-binding protein homologous protein (CHOP). However, other classical ER stress-induced markers such as up-regulation of ER chaperone Bip......-induced beta-cell death. These data suggest that NO generation and direct SERCA2 inhibition cause two quantitative and qualitative different forms of ER stress. In contrast to NO, direct ER stress induced by SERCA inhibition causes activation of ER stress signaling pathways and elicit proapoptotic signaling...

  13. Inhibition of Nuclear Factor-kappa B or Bax Prevents Endoplasmic Reticulum Stress-But Not Nitric Oxide-Mediated Apoptosis in INS-1E Cells

    DEFF Research Database (Denmark)

    Tonnesen, M.F.; Grunnet, L.G.; Friberg, J.;

    2009-01-01

    elicited by NO and ER Ca2+ depletion differ, we here compare the direct effects of NO, in the form of the NO donor S-nitroso-N-acetyl-D, L-penicillamine (SNAP), with the effects of SERCA2 inhibitor thapsigargin (TG) on MAPK, nuclear factor kappa B (NF kappa B), Bcl-2 proteins, ER stress, and apoptosis...

  14. Serum from achalasia patients alters neurochemical coding in the myenteric plexus and nitric oxide mediated motor response in normal human fundus

    NARCIS (Netherlands)

    des Varannes, SB; Chevalier, J; Pimont, S; Le Neel, JC; Klotz, M; Schafer, KH; Galmiche, JP; Neunlist, M

    2006-01-01

    Background and aims: Achalasia is a disease of unknown aetiology. An immune mechanism has been suggested on the basis of previous morphological observations. The objective of this study was to test whether the serum of achalasia patients could reproduce the phenotype and functional changes that occu

  15. A novel soluble immune-type receptor (SITR) in teleost fish: carp SITR is involved in the nitric oxide-mediated response to a protozoan parasite

    NARCIS (Netherlands)

    Ribeiro, C.M.S.; Raes, G.; Ghassabeh, G.H.; Schijns, V.E.J.C.; Pontes, M.J.S.L.; Savelkoul, H.F.J.; Wiegertjes, G.F.

    2011-01-01

    Background- The innate immune system relies upon a wide range of germ-line encoded receptors including a large number of immunoglobulin superfamily (IgSF) receptors. Different Ig-like immune receptor families have been reported in mammals, birds, amphibians and fish. Most innate immune receptors of

  16. The role of nitric oxide in reproduction

    Directory of Open Access Journals (Sweden)

    McCann S.M.

    1999-01-01

    Full Text Available Nitric oxide (NO plays a crucial role in reproduction at every level in the organism. In the brain, it activates the release of luteinizing hormone-releasing hormone (LHRH. The axons of the LHRH neurons project to the mating centers in the brain stem and by afferent pathways evoke the lordosis reflex in female rats. In males, there is activation of NOergic terminals that release NO in the corpora cavernosa penis to induce erection by generation of cyclic guanosine monophosphate (cGMP. NO also activates the release of LHRH which reaches the pituitary and activates the release of gonadotropins by activating neural NO synthase (nNOS in the pituitary gland. In the gonad, NO plays an important role in inducing ovulation and in causing luteolysis, whereas in the reproductive tract, it relaxes uterine muscle via cGMP and constricts it via prostaglandins (PG.

  17. Cyclic Vomiting Syndrome

    Science.gov (United States)

    ... digestive diseases specialist (gastroenterologist). If you or your child is in the middle of a severe vomiting episode, the doctor may ... system disorders There's no cure for cyclic vomiting syndrome, so treatment ... may be prescribed: Anti-nausea drugs Sedatives Medications ...

  18. Cyclic Voltammetry Experiment.

    Science.gov (United States)

    Van Benschoten, James J.; And Others

    1983-01-01

    Describes a three-part experiment designed to introduce cyclic voltammetry to graduate/undergraduate students. Part 1 demonstrates formal reduction potential, redox electron transfer, diffusion coefficient, and electrochemical reversibility. Part 2 investigates electrochemical behavior of acetaminophen. Part 3 examines such experimental variables…

  19. On Expanded Cyclic Codes

    CERN Document Server

    Wu, Yingquan

    2008-01-01

    The paper has a threefold purpose. The first purpose is to present an explicit description of expanded cyclic codes defined in $\\GF(q^m)$. The proposed explicit construction of expanded generator matrix and expanded parity check matrix maintains the symbol-wise algebraic structure and thus keeps many important original characteristics. The second purpose of this paper is to identify a class of constant-weight cyclic codes. Specifically, we show that a well-known class of $q$-ary BCH codes excluding the all-zero codeword are constant-weight cyclic codes. Moreover, we show this class of codes achieve the Plotkin bound. The last purpose of the paper is to characterize expanded cyclic codes utilizing the proposed expanded generator matrix and parity check matrix. We analyze the properties of component codewords of a codeword and particularly establish the precise conditions under which a codeword can be represented by a subbasis. With the new insights, we present an improved lower bound on the minimum distance of...

  20. Cyclic Voltammetry Experiment.

    Science.gov (United States)

    Van Benschoten, James J.; And Others

    1983-01-01

    Describes a three-part experiment designed to introduce cyclic voltammetry to graduate/undergraduate students. Part 1 demonstrates formal reduction potential, redox electron transfer, diffusion coefficient, and electrochemical reversibility. Part 2 investigates electrochemical behavior of acetaminophen. Part 3 examines such experimental variables…

  1. Cyclic Voltammograms from First Principles

    DEFF Research Database (Denmark)

    Karlberg, Gustav; Jaramillo, Thomas; Skulason, Egill

    2007-01-01

    Cyclic voltammetry is a fundamental experimental tool for characterizing electrochemical surfaces. Whereas cyclic voltammetry is widely used within the field of electrochemistry, a way to quantitatively and directly relate the cyclic voltammogram to ab initio calculations has been lacking, even f...

  2. Nitric oxide-induced changes in endothelial expression of phosphodiesterases 2, 3, and 5

    DEFF Research Database (Denmark)

    Schankin, Christoph J; Kruse, Lars S; Reinisch, Veronika M;

    2010-01-01

    line containing such PDEs. METHODS: Real time polymerase chain reaction and Western blots were used to show expression of PDE2A, PDE3B, and PDE5A in a stable cell line of human brain microvascular endothelial cells. Effects of NO on PDE expression were analyzed at specific time intervals after......OBJECTIVE: To investigate nitric oxide (NO)-mediated changes in expression of cyclic nucleotide degrading phosphodiesterases 2A (PDE2A), PDE3B, and PDE5A in human endothelial cells. BACKGROUND: Nitric oxide induces production of cyclic guanosine monophosphate (cGMP), which along with cyclic...... adenosine monophosphate (cAMP) is degraded by PDEs. NO donors and selective inhibitors of PDE3 and PDE5 induce migraine-like headache and play a role in endothelial dysfunction during stroke. The current study investigates possible NO modulation of cGMP-related PDEs relevant to headache induction in a cell...

  3. Dynamics of cyclic machines

    CERN Document Server

    Vulfson, Iosif

    2015-01-01

    This book focuses on modern methods of oscillation analysis in machines, including cyclic action mechanisms (linkages, cams, steppers, etc.). It presents schematization techniques and mathematical descriptions of oscillating systems, taking into account the variability of the parameters and nonlinearities, engineering evaluations of dynamic errors, and oscillation suppression methods. The majority of the book is devoted to the development of new methods of dynamic analysis and synthesis for cyclic machines that form regular oscillatory systems with multiple duplicate modules.  There are also sections examining aspects of general engineering interest (nonlinear dissipative forces, systems with non-stationary constraints, impacts and pseudo-impacts in clearances, etc.)  The examples in the book are based on the widely used results of theoretical and experimental studies as well as engineering calculations carried out in relation to machines used in the textile, light, polygraphic and other industries. Particu...

  4. The Cyclic Model Simplified

    CERN Document Server

    Steinhardt, P J; Steinhardt, Paul J.; Turok, Neil

    2004-01-01

    The Cyclic Model attempts to resolve the homogeneity, isotropy, and flatness problems and generate a nearly scale-invariant spectrum of fluctuations during a period of slow contraction that precedes a bounce to an expanding phase. Here we describe at a conceptual level the recent developments that have greatly simplified our understanding of the contraction phase and the Cyclic Model overall. The answers to many past questions and criticisms are now understood. In particular, we show that the contraction phase has equation of state w>1 and that contraction with w>1 has a surprisingly similar properties to inflation with w < -1/3. At one stroke, this shows how the model is different from inflation and why it may work just as well as inflation in resolving cosmological problems.

  5. Diagnosis of Cyclic Vomiting

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-12-01

    Full Text Available In a study at Children’s Hospital, Ann Arbor, MI, and Children’s Memorial Hospital, Chicago, designed primarily to compare cost-effectiveness of three methods of management of cyclic vomiting cases, one group of patients received an extensive diagnostic evaluation, a second was treated with empiric antimigraine drugs for 2 months, and a third an upper GI series with small-bowel follow-through (UGI-SBFT plus empiric therapy.

  6. Geometry of Cyclic Pursuit

    Science.gov (United States)

    2009-12-18

    analysis of the equilibria based on linearization of the shape dynamics. In [10], the authors extend their analysis to incorporate feedback control...differentiable curves in R2, deriving our dynamics from the natural Frenet frame equations (see, e.g., [5] for details). (A three- dimensional analysis of...cyclic pursuit formulated in terms of the natural Frenet frame equations is a topic of ongoing work.) As is depicted in figure 1, we let ri denote the

  7. Equol reverses the inhibition of cyclosporin A on the proliferation and osteoblastic differentiation of bone marrow mesenchymal stem cells through estrogen receptor/nitric oxide/cyclic guanosine monophosphate signal pathway%雌激素受体/一氧化氮/环磷酸鸟苷通路介导雌马酚逆转环孢素抑制骨髓间充质干细胞增殖及向成骨细胞的分化

    Institute of Scientific and Technical Information of China (English)

    宋丽华; 黄燕; 武翠玲; 石变华

    2010-01-01

    BACKGROUND: Long term taking cyclosporin A(CsA)can inhibit osteoblastic differentiation and induce osteoporosis.Equol,which has greater binding affinity to estrogen receptors,can stimulate the proliferation and osteoblastic differentiation.OBJECTIVE: To investigate whether equol may protect against the proliferation and osteoblastic differentiation inhibited by CsA in mouse bone marrow mesenchymal stem cells(BMSCs)cultures and analyze signal pathway of protection.METHODS: Primary mouse BMSCs were cultured by using attachment method and assigned to five groups,which respectively treated with equol or/and CsA in the presence or absence of ICI182780,an estrogen receptor antagonist,and Nω-nitro-L-arginine methyl ester.Under an inverted microscope,morphological changes and mineralization ability of BMSCs were observed.The cell proliferation was measured by[3H]-thymidine incorporation.The osteoblastic differentiation and mineralization of extracellular matrix in BMSCs was assessed by measuring alkaline phosphatase activity and calcium deposition,respectively.Nitric oxide production in the conditioned media and cyclic guanosine monophosphata(cGMP)content in BMSCs were determined by using commercial nitric oxide and cGMP kit,respectively.RESULTS AND CONCLUSION: Equol reversed the decreased[3H]thymidine incorporation(P < 0.05),alkaline phosphatase activity(P < 0.05)and calcium deposition(P < 0.01)of CsA,which was accompanied with the changes of nitric oxide production(P < 0.01)and cGMP content(P < 0.01).The group by co-treatment with equol and CsA possessed higher cells growth density and small mineralized nodes than CsA group on day 12 under an inverted microscope.Moreover,the equol-reversed effect was abolished by ICI182780 and Nω-nitro-L-arginine methyl ester.These indicated that equol can reverse the inhibition of CsA on the proliferation and osteoblastic differentiation of mouse BMSCs through estrogen receptor/nitric oxide/cGMP signal pathway.%背景:长期服用环

  8. Nitric oxide-related drug targets in headache

    DEFF Research Database (Denmark)

    Olesen, Jes

    2010-01-01

    -called delayed headache that fulfils criteria for migraine without aura in migraine sufferers. Blockade of nitric oxide synthases (NOS) by L-nitromonomethylarginine effectively treats attacks of migraine without aura. Similar results have been obtained for chronic the tension-type headache and cluster headache....... Inhibition of the breakdown of cyclic guanylate phosphate (cGMP) also provokes migraine in sufferers, indicating that cGMP is the effector of NO-induced migraine. Similar evidence suggests an important role of NO in the tension-type headache and cluster headache. These very strong data from human......SUMMARY: Nitric oxide (NO) is a very important molecule in the regulation of cerebral and extra cerebral cranial blood flow and arterial diameters. It is also involved in nociceptive processing. Glyceryl trinitrate (GTN), a pro-drug for NO, causes headache in normal volunteers and a so...

  9. Overexpressed neuroglobin raises threshold for nitric oxide-induced impairment of mitochondrial respiratory activities and stress signaling in primary cortical neurons.

    Science.gov (United States)

    Singh, Shilpee; Zhuo, Ming; Gorgun, Falih M; Englander, Ella W

    2013-08-01

    Surges of nitric oxide compromise mitochondrial respiration primarily by competitive inhibition of oxygen binding to cytochrome c oxidase (complex IV) and are particularly injurious in neurons, which rely on oxidative phosphorylation for all their energy needs. Here, we show that transgenic overexpression of the neuronal globin protein, neuroglobin, helps diminish protein nitration, preserve mitochondrial function and sustain ATP content of primary cortical neurons challenged by extended nitric oxide exposure. Specifically, in transgenic neurons, elevated neuroglobin curtailed nitric oxide-induced alterations in mitochondrial oxygen consumption rates, including baseline oxygen consumption, consumption coupled with ATP synthesis, proton leak and spare respiratory capacity. Concomitantly, activation of genes involved in sensing and responding to oxidative/nitrosative stress, including the early-immediate c-Fos gene and the phase II antioxidant enzyme, heme oxygenase-1, was diminished in neuroglobin-overexpressing compared to wild-type neurons. Taken together, these differences reflect a lesser insult produced by similar concentrations of nitric oxide in neuroglobin-overexpressing compared to wild-type neurons, suggesting that abundant neuroglobin buffers nitric oxide and raises the threshold of nitric oxide-mediated injury in neurons.

  10. Cyclic Nucleotide Monophosphates and Their Cyclases in Plant Signaling

    KAUST Repository

    Gehring, Christoph A.

    2017-10-04

    The cyclic nucleotide monophosphates (cNMPs), and notably 3′,5′-cyclic guanosine monophosphate (cGMP) and 3′,5′-cyclic adenosine monophosphate (cAMP) are now accepted as key signaling molecules in many processes in plants including growth and differentiation, photosynthesis, and biotic and abiotic defense. At the single molecule level, we are now beginning to understand how cNMPs modify specific target molecules such as cyclic nucleotide-gated channels, while at the systems level, a recent study of the Arabidopsis cNMP interactome has identified novel target molecules with specific cNMP-binding domains. A major advance came with the discovery and characterization of a steadily increasing number of guanylate cyclases (GCs) and adenylate cyclases (ACs). Several of the GCs are receptor kinases and include the brassinosteroid receptor, the phytosulfokine receptor, the Pep receptor, the plant natriuretic peptide receptor as well as a nitric oxide sensor. We foresee that in the near future many more molecular mechanisms and biological roles of GCs and ACs and their catalytic products will be discovered and further establish cNMPs as a key component of plant responses to the environment.

  11. Ekpyrotic and Cyclic Cosmology

    CERN Document Server

    Lehners, Jean-Luc

    2008-01-01

    Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes - and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w=P/rho >> 1 (where P is the average pressure and rho the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, thei...

  12. Ekpyrotic and cyclic cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Lehners, Jean-Luc [Princeton Center for Theoretical Science, Jadwin Hall, Princeton University, Princeton NJ 08544 (United States)], E-mail: jlehners@princeton.edu

    2008-09-15

    Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes - and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w=P/({rho}) >>1 (where P is the average pressure and {rho} the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-Gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, their embedding in M-theory and their viability, with an emphasis on open issues and observational signatures.

  13. [Asthma and cyclic neutropenia].

    Science.gov (United States)

    Salazar Cabrera, A N; Berrón Pérez, R; Ortega Martell, J A; Onuma Takane, E

    1996-01-01

    We report a male with history of recurrent infections (recurrent oral aphtous disease [ROAD], middle ear infections and pharyngo amigdalitis) every 3 weeks since he was 7 months old. At the age of 3 years cyclic neutropenia was diagnosed with cyclic fall in the total neutrophil count in blood smear every 21 days and prophylactic antimicrobial therapy was indicated. Episodic events every 3 weeks of acute asthma and allergic rhinitis were detected at the age of 6 years old and specific immunotherapy to Bermuda grass was given during 3 years with markedly improvement in his allergic condition but not in the ROAD. He came back until the age of 16 with episodic acute asthma and ROAD. The total neutrophil count failed to 0 every 21 days and surprisingly the total eosinophil count increased up to 2,000 at the same time, with elevation of serum IgE (412 Ul/mL). Specific immunotherapy to D.pt. and Aller.a. and therapy with timomodulin was indicated. After 3 months we observed clinical improvement in the asthmatic condition and the ROAD disappeared, but the total neutrophil count did not improve. We present this case as a rare association between 2 diseases with probably no etiological relationship but may be physiopatological that could help to understand more the pathogenesis of asthma.

  14. Fragmentations of protonated cyclic-glycylglycine and cyclic-alanylalanine

    NARCIS (Netherlands)

    Shek, P. Y. I.; Lau, J. K. C.; Zhao, J. F.; Grzetic, J.; Verkerk, U. H.; Oomens, J.; Hopkinson, A. C.; Siu, K. W. M.

    2012-01-01

    Collision-induced dissociation has been used to study the fragmentations of two protonated diketopiperazines, protonated cyclic-glycylglycine and cyclic-alanylalanine. Protonated cyclo-AA lost CO and (CO + NH3) at low collision energies, channels attributed to dissociation of the O-protonated

  15. Plasma guanosine 3 ',5 '-cyclic monophosphate and severity of peri/intraventricular haemorrhage in the preterm newborn

    NARCIS (Netherlands)

    van Bel, F; Valk, L; Uiterwaal, CSPM; Egberts, J; Krediet, TG

    2002-01-01

    A poorly controlled cerebral circulation. caused by excessive production of nitric oxide. has been suggested as predisposing to peri/intraventricular haemorrhage (PIVH) in the immature neonate. It is hypothesized that a relation exists between plasma cyclic GMP (cGMP) as an effector of endogenous va

  16. Nitric oxide and cardiovascular system.

    Science.gov (United States)

    Cengel, Atiye; Sahinarslan, Asife

    2006-12-01

    Endothelium has many important functions including the control of blood-tissue permeability and vascular tonus, regulation of vascular surface properties for homeostasis and inflammation. Nitric oxide is the chief molecule in regulation of endothelial functions. Nitric oxide deficiency, which is also known as endothelial dysfunction, is the first step for the occurrence of many disease states in cardiovascular system including heart failure, hypertension, dyslipidemia, insulin resistance, diabetes mellitus, hyperhomocysteinemia and smoking. This review deals with the importance of nitric oxide for cardiovascular system. It also includes the latest improvements in the diagnosis and treatment of endothelial dysfunction.

  17. 49 CFR 173.158 - Nitric acid.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as...

  18. 49 CFR 173.337 - Nitric oxide.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric oxide. 173.337 Section 173.337... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.337 Nitric oxide. (a) Nitric oxide must be... valve and valve seat that will not deteriorate in contact with nitric oxide. Cylinders or valves may...

  19. Cyclic cohomology of Hopf algebras

    NARCIS (Netherlands)

    Crainic, M.

    2001-01-01

    We give a construction of ConnesMoscovicis cyclic cohomology for any Hopf algebra equipped with a character Furthermore we introduce a noncommutative Weil complex which connects the work of Gelfand and Smirnov with cyclic cohomology We show how the Weil complex arises naturally when looking at Hopf

  20. Nitric Oxide as a Mediator of Oxidant Lung Injury Due to Paraquat

    Science.gov (United States)

    Berisha, Hasan I.; Pakbaz, Hedayatollah; Absood, Afaf; Said, Sami I.

    1994-08-01

    At low concentrations, nitric oxide is a physiological transmitter, but in excessive concentrations it may cause cell and tissue injury. We report that in acute oxidant injury induced by the herbicide paraquat in isolated guinea pig lungs, nitric oxide synthesis was markedly stimulated, as evidenced by increased levels of cyclic GMP in lung perfusate and of nitrite and L-citrulline production in lung tissue. All signs of injury, including increased airway and perfusion pressures, pulmonary edema, and protein leakage into the airspaces, were dose-dependently attenuated or totally prevented by either N^G-nitro-L-arginine methyl ester or N^ω-nitro-L-arginine, selective and competitive inhibitors of nitric oxide synthase. Protection was reversed by excess L-arginine but not by its enantiomer D-arginine. When blood was added to the lung perfusate, the paraquat injury was moderated or delayed as it was when paraquat was given to anesthetized guinea pigs. The rapid onset of injury and its failure to occur in the absence of Ca2+ suggest that constitutive rather than inducible nitric oxide synthase was responsible for the stimulated nitric oxide synthesis. The findings indicate that nitric oxide plays a critical role in the production of lung tissue injury due to paraquat, and it may be a pathogenetic factor in other forms of oxidant tissue injury.

  1. Nitric oxide-related drug targets in headache

    DEFF Research Database (Denmark)

    Olesen, Jes

    2010-01-01

    SUMMARY: Nitric oxide (NO) is a very important molecule in the regulation of cerebral and extra cerebral cranial blood flow and arterial diameters. It is also involved in nociceptive processing. Glyceryl trinitrate (GTN), a pro-drug for NO, causes headache in normal volunteers and a so-called del......SUMMARY: Nitric oxide (NO) is a very important molecule in the regulation of cerebral and extra cerebral cranial blood flow and arterial diameters. It is also involved in nociceptive processing. Glyceryl trinitrate (GTN), a pro-drug for NO, causes headache in normal volunteers and a so......-called delayed headache that fulfils criteria for migraine without aura in migraine sufferers. Blockade of nitric oxide synthases (NOS) by L-nitromonomethylarginine effectively treats attacks of migraine without aura. Similar results have been obtained for chronic the tension-type headache and cluster headache....... Inhibition of the breakdown of cyclic guanylate phosphate (cGMP) also provokes migraine in sufferers, indicating that cGMP is the effector of NO-induced migraine. Similar evidence suggests an important role of NO in the tension-type headache and cluster headache. These very strong data from human...

  2. Cyclic $n$-gonal Surfaces

    CERN Document Server

    Broughton, S Allen

    2010-01-01

    A cyclic $n$-gonal surface is a compact Riemann surface $X$ of genus $g\\geq 2$ admitting a cyclic group of conformal automorphisms $C$ of order $n$ such that the quotient space $X/C$ has genus 0. In this paper, we provide an overview of ongoing research into automorphism groups of cyclic $n$-gonal surfaces. Much of the paper is expository or will appear in forthcoming papers, so proofs are usually omitted. Numerous explicit examples are presented illustrating the computational methods currently being used to study these surfaces.

  3. Nitric oxide donors enhance the frequency-dependence of dopamine release in nucleus accumbens

    OpenAIRE

    Hartung, Henrike; Threlfell, Sarah; Cragg, Stephanie J

    2011-01-01

    Abstract Dopamine (DA) neurotransmission in the nucleus accumbens (NAc) is critically involved in normal as well as maladaptive motivated behaviours including drug addiction. Whether the striatal neuromodulator nitric oxide (NO) influences DA release in NAc is unknown. We investigated whether exogenous NO modulates DA transmission in NAc core and how this interaction varies depending on frequency of presynaptic activation. We detected DA with cyclic voltammetry at carbon-fiber micr...

  4. Kinetics and thermodynamics of oxidation mediated reaction in L-cysteine and its methyl and ethyl esters in dimethyl sulfoxide-d6 by NMR spectroscopy

    Science.gov (United States)

    Dougherty, Ryan J.; Singh, Jaideep; Krishnan, V. V.

    2017-03-01

    L-Cysteine (L-Cys), L-Cysteine methyl ester (L-CysME) or L-Cysteine ethyl ester (L-CysEE), when dissolved in dimethyl sulfoxide, undergoes an oxidation process. This process is slow enough and leads to nuclear magnetic resonance (NMR) spectral changes that could be monitored in real time. The oxidation mediated transition is modeled as a pseudo-first order kinetics and the thermodynamic parameters are estimated using the Eyring's formulation. L-Cysteine and their esters are often used as biological models due to the remarkable thiol group that can be found in different oxidation states. This oxidation mediated transition is due to the combination of thiol oxidation to a disulfide followed by solvent-induced effects may be relevant in designing cysteine-based molecular models.

  5. Prognosis of Cyclic Vomiting Syndrome

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2016-03-01

    Full Text Available Investigators from Teikyo University School of Medicine, Tokyo, Japan, evaluated the clinical features, prognosis, and prophylaxis of cyclic vomiting syndrome and the relationship between the syndrome and levels of adrenocorticotropic/antidiuretic hormones (ACTH/ADH.

  6. Design of a cyclic multiverse

    National Research Council Canada - National Science Library

    Piao, Yun-Song

    2010-01-01

    Recently, it has been noticed that the amplification of the amplitude of curvature perturbation cycle by cycle can lead to a cyclic multiverse scenario, in which the number of universes increases cycle by cycle...

  7. Algebraic curves of maximal cyclicity

    Science.gov (United States)

    Caubergh, Magdalena; Dumortier, Freddy

    2006-01-01

    The paper deals with analytic families of planar vector fields, studying methods to detect the cyclicity of a non-isolated closed orbit, i.e. the maximum number of limit cycles that can locally bifurcate from it. It is known that this multi-parameter problem can be reduced to a single-parameter one, in the sense that there exist analytic curves in parameter space along which the maximal cyclicity can be attained. In that case one speaks about a maximal cyclicity curve (mcc) in case only the number is considered and of a maximal multiplicity curve (mmc) in case the multiplicity is also taken into account. In view of obtaining efficient algorithms for detecting the cyclicity, we investigate whether such mcc or mmc can be algebraic or even linear depending on certain general properties of the families or of their associated Bautin ideal. In any case by well chosen examples we show that prudence is appropriate.

  8. Cyclic Cushing's syndrome: an overview.

    Science.gov (United States)

    Albiger, Nora Maria Elvira; Scaroni, Carla M; Mantero, Franco

    2007-11-01

    Cyclic Cushing's syndrome (CS) is a disorder in which glucocorticoid levels are alternately normal and high, the latter occurring in episodes that can last from a few days to several months. It is more common in children than in adults. Cyclic CS may be either of the two different forms of CS (ACTH-dependent or -independent CS). Clinically, it may present with one or many symptoms, depending on the duration of disease activity and the timing of the fluctuations. A serotoninergic influence, cyclic changes in central dopaminergic tone, spontaneous episodic hemorrhage in the tumor, and the action of inflammatory cytokines with antitumor properties are some of the mechanisms suggested to explain the physiopathology of this phenomenon but the exact mechanism remains to be clarified. The cyclic pattern of hypercortisolism can delay the final diagnosis of CS and make it difficult to interpret the results of dynamic tests. Patients may have paradoxical responses to dexamethasone that can reflect increasing or decreasing levels of endogenous activity. Hormone assessments have to be repeated periodically when a diagnosis of CS is suspected. The cyclic pattern can also interfere with medical treatment because patients may show unexpected clinical and biochemical signs of hypocortisolism when cortisol secretion cyclically returns to normal, so an accurate follow-up is mandatory in these patients.

  9. Transitive oriented 3-Hypergraphs of cyclic orders

    OpenAIRE

    2012-01-01

    In this paper we introduce the definition of transitivity for oriented 3-hypergraphs in order to study partial and complete cyclic orders. This definition allow us to give sufficient conditions on a partial cyclic order to be totally extendable. Furthermore, we introduce the 3-hypergraph associated to a cyclic permutation and characterize it in terms of cyclic comparability 3-hypergraphs.

  10. Manual for Cyclic Triaxial Test

    DEFF Research Database (Denmark)

    Shajarati, Amir; Sørensen, Kris Wessel; Nielsen, Søren Kjær

    /dynamic triaxial cell is overall constructed in the same way as the static triaxial cell at Aalborg University, but with the ability to apply any kind of load sequence to the test sample. When conducting cyclic triaxial tests, it is recommended that the manual is followed very tediously since there are many steps...... and if they are done improperly or in the wrong order there is a risk of destroying the test sample or obtaining invalid results.......This manual describes the different steps that is included in the procedure for conducting a cyclic triaxial test at the geotechnical Laboratory at Aalborg University. Furthermore it contains a chapter concerning some of the background theory for the static triaxial tests. The cyclic...

  11. Hopf cyclic cohomology and transverse characteristic classes

    CERN Document Server

    Moscovici, Henri

    2010-01-01

    By refining the cyclic cohomological apparatus for computing the Hopf cyclic cohomology of the Hopf algebras associated to infinite primitive Cartan-Lie pseudogroup, we explicitly identify, as a Hopf cyclic complex, the image of the canonical homomorphism from the Gelfand-Fuks complex to the Bott complex for equivariant cohomology. Distinct from the original realization due to A. Connes and the first named author of the cyclic cohomology of such Hopf algebras as differentiable cyclic cohomology, this construction provides a convenient front-end model for their Hopf cyclic cohomology. Relying on it, we produce characteristic homomorphisms from newly developed models for Hopf cyclic characteristic classes to the cyclic cohomology of the convolution algebras of \\'etale holonomy groupoids, which in particular work in the relative case with no compactness restriction. As an illustration, we apply the latter feature to transfer the universal Hopf cyclic Chern classes found by us in a previous paper, and produce in ...

  12. Design of a cyclic multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Piao Yunsong, E-mail: yspiao@gucas.ac.c [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)

    2010-08-09

    Recently, it has been noticed that the amplification of the amplitude of curvature perturbation cycle by cycle can lead to a cyclic multiverse scenario, in which the number of universes increases cycle by cycle. However, this amplification will also inevitably induce either the ultimate end of corresponding cycle, or the resulting spectrum of perturbations inside corresponding universe is not scale invariant, which baffles the existence of observable universes. In this Letter, we propose a design of a cyclic multiverse, in which the observable universe can emerges naturally. The significance of a long period of dark energy before the turnaround of each cycle for this implementing is shown.

  13. Recursive processing of cyclic graphs.

    Science.gov (United States)

    Bianchini, Monica; Gori, Marco; Sarti, Lorenzo; Scarselli, Franco

    2006-01-01

    Recursive neural networks are a powerful tool for processing structured data. According to the recursive learning paradigm, the input information consists of directed positional acyclic graphs (DPAGs). In fact, recursive networks are fed following the partial order defined by the links of the graph. Unfortunately, the hypothesis of processing DPAGs is sometimes too restrictive, being the nature of some real-world problems intrinsically cyclic. In this paper, a methodology is proposed, which allows us to process any cyclic directed graph. Therefore, the computational power of recursive networks is definitely established, also clarifying the underlying limitations of the model.

  14. Nitric oxide: promoter or suppressor of programmed cell death?

    Science.gov (United States)

    Wang, Yiqin; Chen, Chen; Loake, Gary J; Chu, Chengcai

    2010-02-01

    Nitric oxide (NO) is a short-lived gaseous free radical that predominantly functions as a messenger and effector molecule. It affects a variety of physiological processes, including programmed cell death (PCD) through cyclic guanosine monophosphate (cGMP)-dependent and - independent pathways. In this field, dominant discoveries are the diverse apoptosis networks in mammalian cells, which involve signals primarily via death receptors (extrinsic pathway) or the mitochondria (intrinsic pathway) that recruit caspases as effector molecules. In plants, PCD shares some similarities with animal cells, but NO is involved in PCD induction via interacting with pathways of phytohormones. NO has both promoting and suppressing effects on cell death, depending on a variety of factors, such as cell type, cellular redox status, and the flux and dose of local NO. In this article, we focus on how NO regulates the apoptotic signal cascade through protein S-nitrosylation and review the recent progress on mechanisms of PCD in both mammalian and plant cells.

  15. Enhancement of dendritic branching in cultured hippocampal neurons by 17beta-estradiol is mediated by nitric oxide.

    Science.gov (United States)

    Audesirk, T; Cabell, L; Kern, M; Audesirk, G

    2003-06-01

    Both 17beta-estradiol (E2) and nitric oxide (NO) are important in neuronal development, learning and memory, and age-related memory changes. There is growing evidence that a number of estrogen receptor-mediated effects of estradiol utilize nitric oxide as an intermediary. The role of estradiol in hippocampal neuronal differentiation and function has particular implications for learning and memory. Low levels of estradiol (10nM) significantly increase dendritic branching in cultured embryonic rat hippocampal neurons (158% of control). This study investigates the hypothesis that the estrogen-stimulated increase in dendritic branching is mediated by nitric oxide. We found that nitric oxide donors also produce significantly increased dendritic branching S-nitroso-N-acetylpenicillamine (SNAP: 119%; 2,2'-(hydroxynitrosohydrazino)bis-ethanamine (NOC-18): 128% of control). We then determined that the increases in dendritic branching stimulated by estradiol or by a nitric oxide donor were both blocked by an inhibitor of guanylyl cyclase. Dendritic branching was also stimulated by a cell permeable analog of cyclic guanosine monophosphate (dibutyryl-cGMP: 173% of control). Estradiol-stimulated dendritic branching was reversed by the nitric oxide scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl imidazoline-1-oxyl 3-oxide (carboxy-PTIO). This study provides evidence that estradiol influences the development of embryonic hippocampal neurons in culture by increasing the production of nitric oxide or by increasing the sensitivity of the neurons to nitric oxide. Nitric oxide in turn stimulates dendritic branching via activation of guanylyl cyclase.

  16. Color visualization of cyclic magnitudes

    Science.gov (United States)

    Restrepo, Alfredo; Estupiñán, Viviana

    2014-02-01

    We exploit the perceptual, circular ordering of the hues in a technique for the visualization of cyclic variables. The hue is thus meaningfully used for the indication of variables such as the azimuth and the units of the measurement of time. The cyclic (or circular) variables may be both of the continuous type or the discrete type; among the first there is azimuth and among the last you find the musical notes and the days of the week. A correspondence between the values of a cyclic variable and the chromatic hues, where the natural circular ordering of the variable is respected, is called a color code for the variable. We base such a choice of hues on an assignment of of the unique hues red, yellow, green and blue, or one of the 8 even permutations of this ordered list, to 4 cardinal values of the cyclic variable, suitably ordered; color codes based on only 3 cardinal points are also possible. Color codes, being intuitive, are easy to remember. A possible low accuracy when reading instruments that use this technique is compensated by fast, ludic and intuitive readings; also, the use of a referential frame makes readings precise. An achromatic version of the technique, that can be used by dichromatic people, is proposed.

  17. Cyclic Codes of Length 2

    Indian Academy of Sciences (India)

    Manju Pruthi

    2001-11-01

    In this paper explicit expressions of + 1 idempotents in the ring $R = F_q[X]/\\langle X^{2^m}-1\\rangle$ are given. Cyclic codes of length 2 over the finite field , of odd characteristic, are defined in terms of their generator polynomials. The exact minimum distance and the dimension of the codes are obtained.

  18. Synthesis and characterization of an iron complex bearing a cyclic tetra-N-heterocyclic carbene ligand: An artifical heme analogue?

    KAUST Repository

    Anneser, Markus R.

    2015-04-20

    An iron(II) complex with a cyclic tetradentate ligand containing four N-heterocyclic carbenes was synthesized and characterized by means of NMR and IR spectroscopies, as well as by single-crystal X-ray structure analysis. The iron center exhibits an octahedral coordination geometry with two acetonitrile ligands in axial positions, showing structural analogies with porphyrine-ligated iron complexes. The acetonitrile ligands can readily be substituted by other ligands, for instance, dimethyl sulfoxide, carbon monoxide, and nitric oxide. Cyclic voltammetry was used to examine the electronic properties of the synthesized compounds. © 2015 American Chemical Society.

  19. NO, nitrotyrosine, and cyclic GMP in signal transduction

    Science.gov (United States)

    Hanafy, K. A.; Krumenacker, J. S.; Murad, F.

    2001-01-01

    Over the past 25 years, the role of nitric oxide (NO) in biology has evolved from being recognized as an environmental pollutant to an endogenously produced substance involved in cell communication and signal transduction. NO is produced by a family of enzymes called nitric oxide synthases (NOSs), which can be stimulated by a variety of factors that mediate responses to various stimuli. NO can initiate its biological effects through activation of the heterodimeric enzyme, soluble guanylyl cyclase (sGC), or through several other chemical reactions. Activation of sGC results in the production of 3',5'-cyclic guanosine monophosphate (cGMP), an intracellular second messenger signaling molecule, which can subsequently mediate such diverse physiological events such as vasodilatation and immunomodulation. Chemically reactive NO can affect physiological changes through modifications to cellular proteins, one of which is tyrosine nitration. The demonstration that NO is involved in so many biological pathways indicates the importance of this endogenously produced substance, and suggests that there is much more to be discovered about its role in biology in years to come.

  20. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2016-01-01

    Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. It is vital to reduce corrosion costs and risks in a sustainable manner. The primary objective of this effort is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys.

  1. Powers of Convex-Cyclic Operators

    Directory of Open Access Journals (Sweden)

    Fernando León-Saavedra

    2014-01-01

    Full Text Available A bounded operator T on a Banach space X is convex cyclic if there exists a vector x such that the convex hull generated by the orbit Tnxn≥0 is dense in X. In this note we study some questions concerned with convex-cyclic operators. We provide an example of a convex-cyclic operator T such that the power Tn fails to be convex cyclic. Using this result we solve three questions posed by Rezaei (2013.

  2. CYCLIC CODES OVER FORMAL POWER SERIES RINGS

    Institute of Scientific and Technical Information of China (English)

    Dougherty Steven T.; Liu Hongwei

    2011-01-01

    In this article, cyclic codes and negacyclic codes over formal power series rings are studied. The structure of cyclic codes over this class of rings is given, and the relationship between these codes and cyclic codes over finite chain rings is obtained. Using an isomorphism between cyclic and negacyclic codes over formal power series rings, the structure of negacyclic codes over the formal power series rings is obtained.

  3. 40 CFR 721.2120 - Cyclic amide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Cyclic amide. 721.2120 Section 721... Cyclic amide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a cyclic amide (PMN P-92-131) is subject to reporting under this section for...

  4. The cyclic theory of Hopf algebroids

    NARCIS (Netherlands)

    Kowalzig, N.; Posthuma, H.

    2011-01-01

    We give a systematic description of the cyclic cohomology theory of Hopf alge\\-broids in terms of its associated category of modules. Then we introduce a dual cyclic homology theory by applying cyclic duality to the underlying cocyclic object. We derive general structure theorems for these theories

  5. The Cyclic Graph of a Finite Group

    Directory of Open Access Journals (Sweden)

    Xuan Long Ma

    2013-01-01

    and characterize certain finite groups whose cyclic graphs have some properties. Then, we present some properties of the cyclic graphs of the dihedral groups D2n and the generalized quaternion groups Q4n for some n. Finally, we present some parameters about the cyclic graphs of finite noncyclic groups of order up to 14.

  6. Excitatory response of rabbit myometrium to nitric oxide in vitro.

    Science.gov (United States)

    Nakanishi, H; Matsuoka, I; Ono, T; Okawa, T; Katahira, K; Nakahata, N

    1996-05-01

    Nitric oxide (NO) at high concentration (approx. 33 microM) produced a marked excitation: increase of tension development or increase in amplitude of spontaneous contraction, in 7 out of 8 rabbit nonpregnant myometrial strips. One case produced an inhibition: disappearance of spontaneous contraction. A latent period of several sec usually preceded the excitation. The response of the myometrium to NO approx. 33 microM associated with remarkable increase in tissue cyclic GMP levels. NO approx. 33 microM reduced an inhibition, in 1 out of 3 myometrial strips taken from ovariectomized rabbits. Two cases produced an excitatory. A precursor of NO, L-Arginine 100 microM or an inhibitor of NO synthase, NG-nitro-L-arginine 100 microM also produced a transient weak excitatory response. On the contrary, 8-bromo-cyclic GMP 100 microM produced an inhibition. The excitatory response to NO 33 microM was almost unaffected by pretreatment with indomethacin 10 microM, whereas the spontaneous motility was remarkably depressed. The contractile response of the isolated rabbit myometrium to electrical field stimulation was almost unaffected by the pretreatment with L-arginine 100 microM or NG-nitro-L-arginine 100 microM. The present findings may indicate that NO has inhibitory and excitatory components on the mechanical activity of the rabbit isolated myometrium.

  7. Cyclical Fluctuations in Workplace Accidents

    OpenAIRE

    Boone, J.; J. C. VAN OURS

    2002-01-01

    This Paper presents a theory and an empirical investigation on cyclical fluctuations in workplace accidents. The theory is based on the idea that reporting an accident dents the reputation of a worker and raises the probability that he is fired. Therefore a country with a high or an increasing unemployment rate has a low (reported) workplace accident rate. The empirical investigation concerns workplace accidents in OECD countries. The analysis confirms that workplace accident rates are invers...

  8. The Oxidation of Hydrazine by Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, D.G.

    2001-07-02

    Hydrazine nitrate-nitric acid solutions are used in the ion exchange process for separating Pu-238 and Np-237 and have been found to dissolve plutonium metal in a manner advantageous to SRP metal recovery operations. Laboratory tests on the stability of hydrazine in nitric acid solutions were performed to obtain accurate data, and the results of these tests are reported here. These tests provide sufficient information to specify temperature control for hydrazine-nitric acid solutions in plant processes.

  9. Supramolecular nesting of cyclic polymers.

    Science.gov (United States)

    Kondratuk, Dmitry V; Perdigão, Luís M A; Esmail, Ayad M S; O'Shea, James N; Beton, Peter H; Anderson, Harry L

    2015-04-01

    Advances in template-directed synthesis make it possible to create artificial molecules with protein-like dimensions, directly from simple components. These synthetic macromolecules have a proclivity for self-organization that is reminiscent of biopolymers. Here, we report the synthesis of monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C–C bonds). The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organization, combining encapsulation and nesting; one nanoring adopts a near-circular conformation, thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions there is stacking or nesting, but not a combination of both.

  10. Cyclic modular beta-sheets.

    Science.gov (United States)

    Woods, R Jeremy; Brower, Justin O; Castellanos, Elena; Hashemzadeh, Mehrnoosh; Khakshoor, Omid; Russu, Wade A; Nowick, James S

    2007-03-07

    The development of peptide beta-hairpins is problematic, because folding depends on the amino acid sequence and changes to the sequence can significantly decrease folding. Robust beta-hairpins that can tolerate such changes are attractive tools for studying interactions involving protein beta-sheets and developing inhibitors of these interactions. This paper introduces a new class of peptide models of protein beta-sheets that addresses the problem of separating folding from the sequence. These model beta-sheets are macrocyclic peptides that fold in water to present a pentapeptide beta-strand along one edge; the other edge contains the tripeptide beta-strand mimic Hao [JACS 2000, 122, 7654] and two additional amino acids. The pentapeptide and Hao-containing peptide strands are connected by two delta-linked ornithine (deltaOrn) turns [JACS 2003, 125, 876]. Each deltaOrn turn contains a free alpha-amino group that permits the linking of individual modules to form divalent beta-sheets. These "cyclic modular beta-sheets" are synthesized by standard solid-phase peptide synthesis of a linear precursor followed by solution-phase cyclization. Eight cyclic modular beta-sheets 1a-1h containing sequences based on beta-amyloid and macrophage inflammatory protein 2 were synthesized and characterized by 1H NMR. Linked cyclic modular beta-sheet 2, which contains two modules of 1b, was also synthesized and characterized. 1H NMR studies show downfield alpha-proton chemical shifts, deltaOrn delta-proton magnetic anisotropy, and NOE cross-peaks that establish all compounds but 1c and 1g to be moderately or well folded into a conformation that resembles a beta-sheet. Pulsed-field gradient NMR diffusion experiments show little or no self-association at low (

  11. Nitric oxide-dependent activation of CaMKII increases diastolic sarcoplasmic reticulum calcium release in cardiac myocytes in response to adrenergic stimulation.

    Directory of Open Access Journals (Sweden)

    Jerry Curran

    Full Text Available Spontaneous calcium waves in cardiac myocytes are caused by diastolic sarcoplasmic reticulum release (SR Ca(2+ leak through ryanodine receptors. Beta-adrenergic (β-AR tone is known to increase this leak through the activation of Ca-calmodulin-dependent protein kinase (CaMKII and the subsequent phosphorylation of the ryanodine receptor. When β-AR drive is chronic, as observed in heart failure, this CaMKII-dependent effect is exaggerated and becomes potentially arrhythmogenic. Recent evidence has indicated that CaMKII activation can be regulated by cellular oxidizing agents, such as reactive oxygen species. Here, we investigate how the cellular second messenger, nitric oxide, mediates CaMKII activity downstream of the adrenergic signaling cascade and promotes the generation of arrhythmogenic spontaneous Ca(2+ waves in intact cardiomyocytes. Both SCaWs and SR Ca(2+ leak were measured in intact rabbit and mouse ventricular myocytes loaded with the Ca-dependent fluorescent dye, fluo-4. CaMKII activity in vitro and immunoblotting for phosphorylated residues on CaMKII, nitric oxide synthase, and Akt were measured to confirm activity of these enzymes as part of the adrenergic cascade. We demonstrate that stimulation of the β-AR pathway by isoproterenol increased the CaMKII-dependent SR Ca(2+ leak. This increased leak was prevented by inhibition of nitric oxide synthase 1 but not nitric oxide synthase 3. In ventricular myocytes isolated from wild-type mice, isoproterenol stimulation also increased the CaMKII-dependent leak. Critically, in myocytes isolated from nitric oxide synthase 1 knock-out mice this effect is ablated. We show that isoproterenol stimulation leads to an increase in nitric oxide production, and nitric oxide alone is sufficient to activate CaMKII and increase SR Ca(2+ leak. Mechanistically, our data links Akt to nitric oxide synthase 1 activation downstream of β-AR stimulation. Collectively, this evidence supports the hypothesis

  12. Sectoral Shifts and Cyclical Fluctuations Sectoral Shifts and Cyclical Fluctuations

    Directory of Open Access Journals (Sweden)

    Richard Rogerson

    1991-03-01

    Full Text Available Sectoral Shifts and Cyclical Fluctuations This paper studies a two sector real business cycle model in which the sectors experience different trend rates of growth and labor mobility is costly. Predictions are derived concerning the correlation between sectoral reallocation of workers and the cycle. This correlation may be positive or negative depending upon whether the growing sector displays larger or smaller fluctuations than the shrinking sector. The post- World War II period has witnessed two major patterns of sectoral change in industrialized countries: movement out of agriculture and movement out of the industrial sector. The model's basic prediction is shown to be consistent with the observed pattern of reallocation.

  13. Effect of Different Electrode Materials on the Electropolymerization Process of Aniline in Nitric Acid Media

    Science.gov (United States)

    Li, Yaozong; Yi, Yun; Yang, Weifang; Liu, Xiaoqing; Li, Yuanyuan; Wang, Wei

    2016-11-01

    The electropolymerization process of aniline on different electrode surfaces such as Pt, Au, RuTi and polyaniline film in nitric acid solution containing 1 M aniline was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Proposed electrical equivalent circuits were used to give a further analysis. Results show that the electrode materials accelerate the aniline electropolymerization remarkably as a catalyst, especially the electrochemical oxidation process of monomer aniline to its cation radical, which is the key step to incur the electropolymerization reaction of aniline on the electrode surface. The polymerization of aniline on RuTi electrode has the lowest reaction resistance for its adsorption sites, and the catalytic effects of these different electrodes decrease in the order: RuTi > polyaniline film > Pt > Au. The results also show that several states of polyaniline films are formed during the potential linear scan process in nitric acid solution and the corresponding oxidation and reduction reaction are reversible.

  14. Effect of Different Electrode Materials on the Electropolymerization Process of Aniline in Nitric Acid Media

    Science.gov (United States)

    Li, Yaozong; Yi, Yun; Yang, Weifang; Liu, Xiaoqing; Li, Yuanyuan; Wang, Wei

    2017-02-01

    The electropolymerization process of aniline on different electrode surfaces such as Pt, Au, RuTi and polyaniline film in nitric acid solution containing 1 M aniline was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Proposed electrical equivalent circuits were used to give a further analysis. Results show that the electrode materials accelerate the aniline electropolymerization remarkably as a catalyst, especially the electrochemical oxidation process of monomer aniline to its cation radical, which is the key step to incur the electropolymerization reaction of aniline on the electrode surface. The polymerization of aniline on RuTi electrode has the lowest reaction resistance for its adsorption sites, and the catalytic effects of these different electrodes decrease in the order: RuTi > polyaniline film > Pt > Au. The results also show that several states of polyaniline films are formed during the potential linear scan process in nitric acid solution and the corresponding oxidation and reduction reaction are reversible.

  15. Inducible nitric oxide synthase in renal transplantation

    NARCIS (Netherlands)

    Joles, JA; Vos, IH; Grone, HJ; Rabelink, TJ

    2002-01-01

    The importance of the endothelial isoform of nitric oxide synthase (eNOS) has been well established. Endothelium-derived nitric oxide has been shown to be essential for vascular homeostasis and modulation of eNOS has thus become a target in prevention of cardiovascular disease. The role of the induc

  16. Nitric oxide fumigation for postharvest pest control

    Science.gov (United States)

    Nitric oxide fumigation is effective against all arthropod pests at various life stages tested. Nine insect pests at various life stages and bulb mites were subjected to nitric oxide fumigation treatments under ultralow oxygen conditions of =50 ppm O2 in 1.9L glass jars as fumigation chambers. The ...

  17. The cyclical component factor model

    DEFF Research Database (Denmark)

    Dahl, Christian Møller; Hansen, Henrik; Smidt, John

    Forecasting using factor models based on large data sets have received ample attention due to the models' ability to increase forecast accuracy with respect to a range of key macroeconomic variables in the US and the UK. However, forecasts based on such factor models do not uniformly outperform...... the simple autoregressive model when using data from other countries. In this paper we propose to estimate the factors based on the pure cyclical components of the series entering the large data set. Monte Carlo evidence and an empirical illustration using Danish data shows that this procedure can indeed...

  18. Cyclic voltammetry of supported BLMs

    Science.gov (United States)

    Murgasova, Renata; Sabo, Jan; Ottova, Angelica L.; Tien, H. T.

    1996-06-01

    The transfer of an electron across a bilayer lipid membrane (BLM) is one of the BLMs most exciting processes. A number of well known electron mediators have been investigated using the method of cyclic voltammetry on a Teflon coated platinum wire, the tip of which has been modified by a self-assembled bilayer lipid membrane (s-BLM). The electrical capacitance of the s-BLM system was measured as a function of frequency. The results are discussed in terms of electron transfer and redox reactions.

  19. The biosynthesis of cyclic carotenes.

    Science.gov (United States)

    Williams, R J; Britton, G; Goodwin, T W

    1967-10-01

    1. The incorporation of (3RS)-[2-(14)C,(4R)-4-(3)H(1)]mevalonic acid into various cyclic carotenes in the fruit of the tomato mutant delta has been studied. The results confirm our previous view that the alpha-ionone ring of alpha-carotene does not arise by isomerization of a beta-ionone residue, and show that the same is also true for the alpha-ionone ring of delta- and in-carotene and alpha-zeacarotene. 2. The incorporation of (3RS)-[2-(14)C,2-(3)H(2)]mevalonic acid into alpha- and beta-carotene in carrot roots has been studied. The results show that the beta-ionone ring of beta-carotene does not arise by isomerization of the alpha-ionone residue of alpha-carotene. 3. These experiments show that alpha- and beta-ionone rings in cyclic carotenes are formed independently, probably by elimination of different protons from the same carbonium ion intermediates.

  20. [Cyclic Cushing's Syndrome - rare or rarely recognized].

    Science.gov (United States)

    Kiałka, Marta; Doroszewska, Katarzyna; Mrozińska, Sandra; Milewicz, Tomasz; Stochmal, Ewa

    2015-01-01

    Cyclic Cushing's syndrome is a type of Cushing's disease which is characterized by alternating periods of increasing and decreasing levels of cortisol in the blood. The diagnostic criteria for cyclic Cushing's syndrome are at least three periods of hypercortisolism alternating with at least two episodes of normal levels of serum cortisol concentration. The epidemiology, signs, symptoms, pathogenesis and treatment of cyclic Cushing's syndrome have been discussed.

  1. Cyclic Cohomology of the Weyl Algebra

    CERN Document Server

    Willwacher, Thomas

    2008-01-01

    We give an explicit formula for symplectically basic representatives of the cyclic cohomology of the Weyl algebra. This paper can be seen as cyclic addendum to the paper by Feigin, Felder and Shoikhet, where the analogous Hochschild case was treated. As an application, we prove a generalization of a Theorem of Nest and Tsygan concerning the relation of the Todd class and the cyclic cohomology of the differential operators on a complex manifold.

  2. Cyclic and Inductive Calculi are equivalent

    CERN Document Server

    Voicu, Razvan

    2011-01-01

    Brotherston and Simpson [citation] have formalized and investigated cyclic reasoning, reaching the important conclusion that it is at least as powerful as inductive reasoning (specifically, they showed that each inductive proof can be translated into a cyclic proof). We add to their investigation by proving the converse of this result, namely that each inductive proof can be translated into an inductive one. This, in effect, establishes the equivalence between first order cyclic and inductive calculi.

  3. Cyclic and Inductive Calculi are equivalent

    OpenAIRE

    Razvan VOICU; Li, Mengran

    2011-01-01

    Brotherston and Simpson [citation] have formalized and investigated cyclic reasoning, reaching the important conclusion that it is at least as powerful as inductive reasoning (specifically, they showed that each inductive proof can be translated into a cyclic proof). We add to their investigation by proving the converse of this result, namely that each inductive proof can be translated into an inductive one. This, in effect, establishes the equivalence between first order cyclic and inductive...

  4. Resveratrol and Endothelial Nitric Oxide

    Directory of Open Access Journals (Sweden)

    Ning Xia

    2014-10-01

    Full Text Available Nitric oxide (NO derived from the endothelial NO synthase (eNOS has antihypertensive, antithrombotic, anti-atherosclerotic and antiobesogenic properties. Resveratrol is a polyphenol phytoalexin with multiple cardiovascular and metabolic effects. Part of the beneficial effects of resveratrol are mediated by eNOS. Resveratrol stimulates NO production from eNOS by a number of mechanisms, including upregulation of eNOS expression, stimulation of eNOS enzymatic activity and reversal of eNOS uncoupling. In addition, by reducing oxidative stress, resveratrol prevents oxidative NO inactivation by superoxide thereby enhancing NO bioavailability. Molecular pathways underlying these effects of resveratrol involve SIRT1, AMPK, Nrf2 and estrogen receptors.

  5. Regulation of p53 by activated protein kinase C-delta during nitric oxide-induced dopaminergic cell death.

    Science.gov (United States)

    Lee, Sung-Jin; Kim, Dong-Chan; Choi, Bo-Hwa; Ha, Hyunjung; Kim, Kyong-Tai

    2006-01-27

    Selective cell death of dopaminergic neurons in the substantia nigra is the major cause of Parkinson disease. Current evidence suggests that this cell death could be mediated by nitric oxide by-products such as nitrate and peroxynitrite. Because protein kinase C (PKC)-delta is implicated in apoptosis of various cell types, we studied its roles and activation mechanisms in nitric oxide (NO)-induced apoptosis of SN4741 dopaminergic cells. When cells were treated with sodium nitroprusside (SNP), a NO donor, endogenous PKC-delta was nitrated and activated. Immunoprecipitation revealed that p53 co-immunoprecipitated with PKC-delta and was phosphorylated at the 15th serine residue in SNP-treated cells. An in vitro kinase assay revealed that p53 was directly phosphorylated by SNP-activated PKC-delta. The p53 Ser-15 phosphorylation was suppressed in SNP-treated cells when the NO-mediated activation of PKC-delta was inhibited by rottlerin or (-)-epigallocatechin gallate. Within 3 h of p53 phosphorylation, its protein levels increased because of decreased ubiquitin-dependent proteosomal proteolysis, whereas the protein levels of MDM2, ubiquitin-protein isopeptide ligase, were down-regulated in a p53 phosphorylation-dependent fashion. Taken together, these results demonstrate that nitration-mediated activation of PKC-delta induces the phosphorylation of the Ser-15 residue in p53, which increases its protein stability, thereby contributing to the nitric oxide-mediated apoptosis-like cell death pathway. These findings may be expanded to provide new insight into the cellular mechanisms of Parkinson disease.

  6. Nitric oxide and chronic colitis

    Directory of Open Access Journals (Sweden)

    Matthew B Grisham

    1996-01-01

    Full Text Available Nitric oxide (NO is thought to play an important role in modulating the inflammatory response by virtue of its ability to affect bloodflow, leukocyte function and cell viability. The objective of this study was to assess the role that NO may play in mediating the mucosal injury and inflammation in a model of chronic granulomatous colitis using two pharmacologically different inhibitors of nitric oxide synthase (NOS. Chronic granulomatous colitis with liver and spleen inflammation was induced in female Lewis rats via the subserosal (intramural injection of peptidoglycan/polysaccharide (PG/PS derived from group A streptococci. Chronic NOS inhibition by oral administration of NG-nitro-L-arginine methyl ester (L-NAME (15 µmol/kg/day or amino-guanidine (AG (15 µmol/ kg/day was found to attenuate the PG/PS-induced increases in macroscopic colonic inflammation scores and colonic myeloperoxidase activity. Only AG -- not L-NAME – attenuated the PG/PS-induced increases in colon dry weight. Both L-NAME and AG significantly attenuated the PG/PS-induced increases in spleen weight whereas neither was effective at significantly attenuating the PG/PS-induced increases in liver weight. Although both L-NAME and AG inhibited NO production in vivo, as measured by decreases in plasma nitrite and nitrate levels, only AG produced significantly lower values (38±3 versus 83±8 µM, respectively, P<0.05. Finally, L-NAME, but not AG, administration significantly increased mean arterial pressure from 83 mmHg in colitic animals to 105 mmHg in the PG/PS+ L-NAME-treated animals (P<0.05. It is concluded that NO may play an important role in mediating some of the pathophysiology associated with this model of chronic granulomatous colitis.

  7. Cell reorientation under cyclic stretching

    CERN Document Server

    Livne, Ariel; Geiger, Benjamin

    2014-01-01

    Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations -- cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell's passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells, measu...

  8. 21 CFR 868.2380 - Nitric oxide analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitric oxide analyzer. 868.2380 Section 868.2380...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2380 Nitric oxide analyzer. (a) Identification. The nitric oxide analyzer is a device intended to measure the concentration of nitric oxide...

  9. 21 CFR 862.3080 - Breath nitric oxide test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath nitric oxide test system. 862.3080 Section... Systems § 862.3080 Breath nitric oxide test system. (a) Identification. A breath nitric oxide test system is a device intended to measure fractional nitric oxide in human breath. Measurement of changes...

  10. Electrochemical Reduction of Oxygen and Nitric Oxide at Low Temperature on La1−xSrxFeO3−δ Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2014-01-01

    degrees C, using cone-shaped electrodes and cyclic voltammetry. It was shown that the ferrites had a higher activity towards the electrochemical reduction of nitric oxide than towards the electrochemical reduction of oxygen, in the investigated temperature range. The highest activity towards...

  11. Cyclic electrophoretic and chromatographic separation methods

    NARCIS (Netherlands)

    Eijkel, Jan C.T.; Berg, van den Albert; Manz, Andreas

    2004-01-01

    A review is given of the application of cyclic analytical methods in capillary electroseparation (CE) and liquid chromatography (LC) systems. Cyclic methods have been used since the early sixties in chromatographic systems to overcome pressure limitations to resolution. From the early nineties on th

  12. Cyclicality in Losses on Bank Loans

    NARCIS (Netherlands)

    B. Keijsers (Bart); B.F. Diris (Bart); H.J.W.G. Kole (Erik)

    2015-01-01

    markdownabstract__Abstract__ Cyclicality in the losses of bank loans is important for bank risk management. Because loans have a different risk profile than bonds, evidence of cyclicality in bond losses need not apply to loans. Based on unique data we show that the default rate and loss given defau

  13. Cyclic malyl anthocyanins in Dianthus caryophyllus.

    Science.gov (United States)

    Nakayama, M; Koshioka, M; Yoshida, H; Kan, Y; Fukui, Y; Koike, A; Yamaguchi, M

    2000-12-01

    3,5-Di-O-(beta-glucopyranosyl) pelargonidin 6''-O-4,6'''-O-1-cyclic malate and a previously reported cyanidin equivalent, 3,5-di-O-(beta-glucopyranosyl) cyanidin 6''-O-4,6'''-O-1-cyclic malate were identified from petals of deep pink and red-purple flower cultivars of Dianthus caryophyllus, respectively.

  14. Products in Hopf-Cyclic Cohomology

    CERN Document Server

    Kaygun, Atabey

    2007-01-01

    We construct several pairings in Hopf-cyclic cohomology of (co)module (co)algebras with arbitrary coefficients. The key ideas instrumental in constructing these pairings are the derived functor interpretation of Hopf-cyclic and equivariant cyclic (co)homology, and the Yoneda interpretation of Ext-groups. As a special case of one of these pairings, we recover the Connes-Moscovici characteristic map in Hopf-cyclic cohomology. We also prove that this particular pairing, along with few others, would stay the same if we replace the derived category of (co)cyclic modules with the homotopy category of (special) towers of $X$-complexes, or the derived category of mixed complexes.

  15. Specificity of the Cyclic GMP-Binding Activity and of a Cyclic GMP-Dependent Cyclic GMP Phosphodiesterase in Dictyostelium discoideum

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Walsum, Hans van; Meer, Rob C. van der; Bulgakov, Roman; Konijn, Theo M.

    1982-01-01

    The nucleotide specificity of the cyclic GMP-binding activity in a homogenate of Dictyostelium discoideum was determined by competition of cyclic GMP derivatives with [8-3H] cyclic GMP for the binding sites. The results indicate that cyclic GMP is bound to the binding proteins by hydrogen bonds at N

  16. Nitric oxide inhibits the accumulation of CD4+CD44hiTbet+CD69lo T cells in mycobacterial infection

    Science.gov (United States)

    Pearl, John E.; Torrado, Egidio; Tighe, Michael; Fountain, Jeffrey J.; Solache, Alejandra; Strutt, Tara; Swain, Susan; Appelberg, Rui; Cooper, Andrea M

    2013-01-01

    Summary Animals lacking the inducible nitric oxide synthase gene (nos2−/−) are less susceptible to M. avium strain 25291 and lack nitric oxide-mediated immunomodulation of CD4+ T cells. Here we show that the absence of nos2 results in increased accumulation of neutrophils and both CD4+ and CD8+ T cells within the M. avium-containing granuloma. Examination of the T-cell phenotype in M. avium-infected mice demonstrated that CD4+CD44hi effector T cells expressing the Th1 transcriptional regulator T-bet (T-bet+) were specifically reduced by the presence of nitric oxide. Importantly, the T-bet+ effector population could be separated into CD69hi and CD69lo populations, with the CD69lo population only able to accumulate during chronic infection within infected nos2−/− mice. Transcriptomic comparison between CD4+CD44hiCD69hi and CD4+CD44hiCD69lo populations revealed that CD4+CD44hiCD69lo cells had higher expression of the integrin itgb1/itga4 (VLA-4, CD49d/CD29). Inhibition of Nos2 activity allowed increased accumulation of the CD4+CD44hiT-bet+CD69lo population in WT mice as well as increased expression of VLA-4. These data support the hypothesis that effector T cells in mycobacterial granulomata are not a uniform effector population but exist in distinct subsets with differential susceptibility to the regulatory effects of nitric oxide. PMID:22890814

  17. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2015-01-01

    The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC), Florida, has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of NASA and the GSDO Program, the objective of this project is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys. This project is a direct follow-on to United Space Alliance (USA) work at KSC to optimize the parameters for the use of citric acid and verify effectiveness. This project will build off of the USA study to further evaluate citric acids effectiveness and suitability for corrosion protection of a number of stainless steels alloys used by NASA, the Department of Defense (DoD), and the European Space Agency (ESA).

  18. Nitric oxide bioavailability in malaria.

    Science.gov (United States)

    Sobolewski, Peter; Gramaglia, Irene; Frangos, John; Intaglietta, Marcos; van der Heyde, Henri C

    2005-09-01

    Rational development of adjunct or anti-disease therapy for severe Plasmodium falciparum malaria requires cellular and molecular definition of malarial pathogenesis. Nitric oxide (NO) is a potential target for such therapy but its role during malaria is controversial. It has been proposed that NO is produced at high levels to kill Plasmodium parasites, although the unfortunate consequence of elevated NO levels might be impaired neuronal signaling, oxidant damage and red blood cell damage that leads to anemia. In this case, inhibitors of NO production or NO scavengers might be an effective adjunct therapy. However, increasing amounts of evidence support the alternate hypothesis that NO production is limited during malaria. Furthermore, the well-documented NO scavenging by cell-free plasma hemoglobin and superoxide, the levels of which are elevated during malaria, has not been considered. Low NO bioavailability in the vasculature during malaria might contribute to pathologic activation of the immune system, the endothelium and the coagulation system: factors required for malarial pathogenesis. Therefore, restoring NO bioavailability might represent an effective anti-disease therapy.

  19. Cyclic Shearing Deformation Behavior of Saturated Clays

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay's strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The deformations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deformation and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.

  20. Integrins mediate mechanical compression-induced endothelium-dependent vasodilation through endothelial nitric oxide pathway.

    Science.gov (United States)

    Lu, Xiao; Kassab, Ghassan S

    2015-09-01

    Cardiac and skeletal muscle contraction lead to compression of intramuscular arterioles, which, in turn, leads to their vasodilation (a process that may enhance blood flow during muscle activity). Although endothelium-derived nitric oxide (NO) has been implicated in compression-induced vasodilation, the mechanism whereby arterial compression elicits NO production is unclear. We cannulated isolated swine (n = 39) myocardial (n = 69) and skeletal muscle (n = 60) arteriole segments and exposed them to cyclic transmural pressure generated by either intraluminal or extraluminal pressure pulses to simulate compression in contracting muscle. We found that the vasodilation elicited by internal or external pressure pulses was equivalent; moreover, vasodilation in response to pressure depended on changes in arteriole diameter. Agonist-induced endothelium-dependent and -independent vasodilation was used to verify endothelial and vascular smooth muscle cell viability. Vasodilation in response to cyclic changes in transmural pressure was smaller than that elicited by pharmacological activation of the NO signaling pathway. It was attenuated by inhibition of NO synthase and by mechanical removal of the endothelium. Stemming from previous observations that endothelial integrin is implicated in vasodilation in response to shear stress, we found that function-blocking integrin α5β1 or αvβ3 antibodies attenuated cyclic compression-induced vasodilation and NOx (NO(-)2 and NO(-)3) production, as did an RGD peptide that competitively inhibits ligand binding to some integrins. We therefore conclude that integrin plays a role in cyclic compression-induced endothelial NO production and thereby in the vasodilation of small arteries during cyclic transmural pressure loading.

  1. General solution of cyclic Leibniz rule

    CERN Document Server

    Kadoh, Daisuke

    2015-01-01

    We study the general solution of the cyclic Leibniz rule (CLR) which was recently proposed as a new approach to the lattice supersymmetry. Introducing some mathematical preliminaries associated with the cyclic symmetry, we find the general solution of the 2-body CLR for the naive symmetric difference operator. The main theorems of this paper state that the general solution can be uniquely expressed as (A) a linear combination of the two fundamental solutions with cyclic invariant coefficients, and (B) a linear combination of the minimal solutions with complex coefficients. Moreover, an extension to the general difference operators is also discussed.

  2. Monopod bucket foundations under cyclic lateral loading

    OpenAIRE

    Foglia, Aligi; Ibsen, Lars Bo

    2014-01-01

    The monopod bucket foundation can be a cost-reducing sub-structure for offshore wind turbines. To avoid problems during the turbine operation, the long-term effect of cyclic loading must be considered in the design of the foundation. In this paper a 1g testing rig is adopted to extend the knowledge on bucket foundations under lateral cyclic loading. The test setup is described in detail and a comprehensive experimental campaign is presented. The foundation is subjected to cyclic overturning m...

  3. Cyclic Control Optimization for a Smart Rotor

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Henriksen, Lars Christian

    2012-01-01

    The paper presents a method to determine cyclic control trajectories for a smart rotor undergoing periodic-deterministic load variations. The control trajectories result from a constrained optimization problem, where the cost function to minimize is given by the variation of the blade root flapwise...... bending moment within a rotor revolution. The method is applied to a rotor equipped with trailing edge flaps, and capable of individual blade pitching. Results show that the optimized cyclic control significantly alleviates the load variations from periodic disturbances; the combination of both cyclic...

  4. Inducible nitric oxide synthase is responsible for nitric oxide release from murine pituicytes

    DEFF Research Database (Denmark)

    Kjeldsen, T H; Rivier, C; Lee, S;

    2003-01-01

    This study investigated whether pituicytes were able to produce and release nitric oxide (NO), and which type of nitric oxide synthase (NOS) would be responsible for this phenomenon. Lipopolysaccharide (LPS) 1 micro g/ml was used as inflammatory mediator. Because pituicytes are known to secrete...

  5. Electrochemical Reduction of Oxygen and Nitric Oxide at Low Temperature on La1−xSrxCoO3−delta Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2010-01-01

    Six La1-xSrxCoO3- (x= 0, 0.05, 0.15, 0.25, 0.35, 0.50) perovskites were synthesised and characterised by powder XRD and cyclic voltammetry on cone-shaped electrodes in either air or nitric oxide in argon at 200, 300 and 400oC. At 200oC the current densities in air was highest for the strontium...

  6. Activation of Proinflammatory Responses in Cells of the Airway Mucosa by Particulate Matter: Oxidant- and Non-Oxidant-Mediated Triggering Mechanisms

    Directory of Open Access Journals (Sweden)

    Johan Øvrevik

    2015-07-01

    Full Text Available Inflammation is considered to play a central role in a diverse range of disease outcomes associated with exposure to various types of inhalable particulates. The initial mechanisms through which particles trigger cellular responses leading to activation of inflammatory responses are crucial to clarify in order to understand what physico-chemical characteristics govern the inflammogenic activity of particulate matter and why some particles are more harmful than others. Recent research suggests that molecular triggering mechanisms involved in activation of proinflammatory genes and onset of inflammatory reactions by particles or soluble particle components can be categorized into direct formation of reactive oxygen species (ROS with subsequent oxidative stress, interaction with the lipid layer of cellular membranes, activation of cell surface receptors, and direct interactions with intracellular molecular targets. The present review focuses on the immediate effects and responses in cells exposed to particles and central down-stream signaling mechanisms involved in regulation of proinflammatory genes, with special emphasis on the role of oxidant and non-oxidant triggering mechanisms. Importantly, ROS act as a central second-messenger in a variety of signaling pathways. Even non-oxidant mediated triggering mechanisms are therefore also likely to activate downstream redox-regulated events.

  7. Nitric oxide, inducible nitric oxide synthase and inflammation in veterinary medicine.

    Science.gov (United States)

    Hunter, Robert P

    2002-12-01

    Inflammation is a process consisting of a complex of cytological and chemical reactions which occur in and around affected blood vessels and adjacent tissues in response to an injury caused by a physical, chemical or biological insult. Much work has been performed in the past several years investigating inducible nitric oxide synthase (NOS, EC 1.14.13.39) and nitric oxide in inflammation. This has resulted in a rapid increase in knowledge about iNOS and nitric oxide. Nitric oxide formation from inducible NOS is regulated by numerous inflammatory mediators, often with contradictory effects, depending upon the type and duration of the inflammatory insult. Equine medicine appears to have benefited the most from the increased interest in this small, inflammatory mediator. Most of the information on nitric oxide in traditional veterinary species has been produced using models or naturally occurring inflammatory diseases of this species.

  8. Nitric Oxide and eNOS Gene in Essential Hypertension

    Directory of Open Access Journals (Sweden)

    Kamna Srivastava

    2009-04-01

    Full Text Available Background: Currently hypertension grips around 25% of the entire world population. More than 90% of the hypertensive patients suffer from essential hypertension. In Asian Indians hypertension is the predominant risk factor for Coronary Artery Disease among others. Nitric Oxide (NO is synonymous with endothelial derived relaxation factor. Acting via cGMP (cyclic guanosine monophosphate it causes smooth muscle relaxation, prevents platelet aggregation and acts as an anti-inflammatory agent. iNOS (inducible Nitric oxide synthase, nNOS(neuronal nitric oxide synthase and eNOS (endothelial nitric oxide synthase are the three enzymes producing the gas nitric oxide in the human body. eNOS is the main source of NO under physiological conditions. It is known to have a number of polymorphisms. The most well known ones being the G to T polymorphism in exon 7, the T to C polymorphism in the promoter region and the a/b polymorphism in the intron 4. While the G to T polymorphism has been associated with hypertension in many races including the north Indian population, the association of other polymorphisms has been more of a controversy. Not much study has been done on the Asians especially those in India regarding these polymorphisms. Aims: To elucidate the association between the intron4a/b polymorphism in the eNOS gene and nitric oxide levels and essential hypertension. Objectives: 1. To determine the genotype frequencies of the above mentioned polymorphism in patients and controls2. To study the levels of NO in the plasma of the patients and controls3. To find out correlation if any between this polymorphism and plasma NO levels4. To find a correlation if any between this polymorphism and essential hypertension Materials and Methods: The study design was a case control study. 10 ml of venous blood was taken from 45 patients (selected from the department of Cardiology All India Institute of Medical Sciences, ages between 25 to 55 yrs and not on any

  9. Mortar constituent of concrete under cyclic compression

    Science.gov (United States)

    Maher, A.; Darwin, D.

    1980-10-01

    The behavior of the mortar constituent of concrete under cyclic compression was studied and a simple analytic model was developed to represent its cyclic behavior. Experimental work consisted of monotonic and cyclic compressive loading of mortar. Two mixes were used, with proportions corresponding to concretes having water cement ratios of 0.5 and 0.6. Forty-four groups of specimens were tested at ages ranging from 5 to 70 days. complete monotonic and cyclic stress strain envelopes were obtained. A number of loading regimes were investigated, including cycles to a constant maximum strain. Major emphasis was placed on tests using relatively high stress cycles. Degradation was shown to be a continuous process and a function of both total strain and load history. No stability or fatigue limit was apparent.

  10. The Permutation Groups and the Equivalence of Cyclic and Quasi-Cyclic Codes

    CERN Document Server

    Guenda, Kenza

    2010-01-01

    We give the class of finite groups which arise as the permutation groups of cyclic codes over finite fields. Furthermore, we extend the results of Brand and Huffman et al. and we find the properties of the set of permutations by which two cyclic codes of length p^r can be equivalent. We also find the set of permutations by which two quasi-cyclic codes can be equivalent.

  11. Cyclic Voltammetry And Linear Sweep Voltammetry Study Of Cyclic Tertiary Amines

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ping; TIAN JinPing; YIN YingWu

    2001-01-01

    @@ Cyclic six membered a-aminonitrile have proved to be very versatile synthetic intermediates and have been widely used in the construction of a large number of indole alkaloids. In order to obtain some information about the mechanisn of electrochemical synthesis of aaminonitrile. Electrochemistry behaviors that include cyclic voltammetry and linear sweep voltammetry of cyclic tertiary amines which including N-benzylpiperidine (NBP), 1-(l-Methoxycarbonyl ethyl) piperidine (MCEP), N-methylcarbonylppiperidine (NMCP), Nethylpiperidine(NEP) was studied.

  12. Cyclic Voltammetry And Linear Sweep Voltammetry Study Of Cyclic Tertiary Amines

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Ping

    2001-01-01

    Cyclic six membered a-aminonitrile have proved to be very versatile synthetic intermediates and have been widely used in the construction of a large number of indole alkaloids. In order to obtain some information about the mechanisn of electrochemical synthesis of aaminonitrile. Electrochemistry behaviors that include cyclic voltammetry and linear sweep voltammetry of cyclic tertiary amines which including N-benzylpiperidine (NBP), 1-(l-Methoxycarbonyl ethyl) piperidine (MCEP), N-methylcarbonylppiperidine (NMCP), Nethylpiperidine(NEP) was studied.……

  13. Cyclic Oxonitriles: Stereodivergent Grignard Addition-Alkylations

    OpenAIRE

    Fleming, Fraser F.; Wei, Guoqing; Zhang, Zhiyu; Steward, Omar W.

    2007-01-01

    Sequential carbonyl addition-conjugate addition of Grignard reagents to cyclic 5–7–membered oxoalkenenitriles efficiently generates cyclic magnesiated nitriles. Alkylations of these magnesiated nitriles exhibit diastereoselectivities that depend intimately on the size of the carbocyclic ring: 5-membered oxonitriles generate magnesiated nitriles whose alkylations are controlled by steric constraints whereas 6- and 7-membered oxonitriles generate internally coordinated, C-magnesiated nitriles w...

  14. Total synthesis of cyclic heptapeptide euryjanicin B

    Institute of Scientific and Technical Information of China (English)

    Chun Mei Zhang; Jun Xiang Guo; Liang Wang; Xiao Yun Chai; Hong Gang Hu; Qiu Ye Wu

    2011-01-01

    The first synthesis of the naturally occurring cyclic peptide euryjanicin B has been achieved. A general method was described to synthesize the cyclic peptide by a two-step solid-phase/solution synthesis strategy. All the amino acids in this study are L-configuration, The linear heptapeptide was assembled by standard Fmoc chemistry on solid-phase and subsequently cyclization was carried out by solution method.

  15. Cyclic Period in the CBE Model

    CERN Document Server

    Frampton, Paul H

    2016-01-01

    In a cyclic entropy model in which the extroverse is jettisoned at turnaround with a Come Back Empty (CBE) assumption, we address matching of the contaction scale factor $\\hat{a}(t)=f(t_T){a}(t)$ to the expansion scale factor $a(t)$, where $f(t_T)$ is the ratio at turnaround of the introverse to extroverse radii. Such matching is necessary for infinite cyclicity and fixes the CBE period at $\\sim 2.6Ty$.

  16. Synthesis of Chiral Amino Cyclic Phosphoric Acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Chirai amino cyclic phosphoric acids, 5-amino-2-hydroxy-4- (4-nitrophenyl)-l, 3,2-dioxaphospho- rinane 2-oxide and 2-hydroxy-4- (4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64. 2% and 72. 8% respectively) from 2-amino-l-aryl-l,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

  17. Nitric Oxide Homeostasis in Neurodegenerative Diseases.

    Science.gov (United States)

    Hannibal, Luciana

    2016-01-01

    The role of nitric oxide in the pathogenesis and progression of neurodegenerative illnesses such as Parkinson's and Alzheimer's diseases has become prominent over the years. Increased activity of the enzymes that produce reactive oxygen species, decreased activity of antioxidant enzymes and imbalances in glutathione pools mediate and mark the neurodegenerative process. Much of the oxidative damage of proteins is brought about by the overproduction of nitric oxide by nitric oxide synthases (NOS) and its subsequent reactivity with reactive oxygen species. Proteomic methods have advanced the field tremendously, by facilitating the quantitative assessment of differential expression patterns and oxidative modifications of proteins and alongside, mapping their non-canonical functions. As a signaling molecule involved in multiple biochemical pathways, the level of nitric oxide is subject to tight regulation. All three NOS isoforms display aberrant patterns of expression in Alzheimer's disease, altering intracellular signaling and routing oxidative stress in directions that are uncompounded. This review discusses the prime factors that control nitric oxide biosynthesis, reactivity footprints and ensuing effects in the development of neurodegenerative diseases.

  18. Useful and harmful effects of nitric oxide

    Directory of Open Access Journals (Sweden)

    Jović Slavoljub

    2013-01-01

    Full Text Available In living sistems synthesis of nitric oxide occurs during metabolism from Larginin, nitrite and ascorbate. Being very significant carrier of information within numerous both physiological and pathological proceses in mammals' organisms, nitric oxid could possibly be useful as well as harmful. Nitric oxide synthesis is adjuvant in a healthy organism because it represents the basic molecule for understanding numerous processes in neurology, psychology, immunology and varios related fields. In other words, nitric oxide participate in number of physiological processes, such as: transmission of nerve signals (neurotransmitter role, regulation of smooth muscle tissue relaxation (eg. vasodilatation, peristaltic movements, immunomodulation, mastocyte activation, development of inflammatory response, apoptosis regulation, angiogenesis and glucose metabolism, normal heart functioning and antioxidation role. Besides being useful, nitric oxide can be harmful as well, because it has one unpaired electron, so consequently it is susceptible to oxidation becoming a stable free radical. Being such, it reacts quickly with superoxide-anion radical, givind at first an extremely reactive peroxinitrite anion, and subsequently peroxidnitrite acid. This acid is very dangerous causing thiol groups oxidation, tyrosine and phenylalanine nitrosylation, lipid oxidation, DNK chain splitting, nitrification and nucleic bases deamination. These damages of macromolecules can cause a series of undesirable changes which subsequently distub functions of molecules, and thus of cells, tissues and even organs. [Projekat Ministarstva nauke Republike Srbije, br. 173034 i br. 31085

  19. Antimicrobial cyclic peptides for plant disease control.

    Science.gov (United States)

    Lee, Dong Wan; Kim, Beom Seok

    2015-03-01

    Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  20. Antimicrobial Cyclic Peptides for Plant Disease Control

    Directory of Open Access Journals (Sweden)

    Dong Wan Lee

    2015-03-01

    Full Text Available Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  1. Cyclic behaviors of amorphous shape memory polymers.

    Science.gov (United States)

    Yu, Kai; Li, Hao; McClung, Amber J W; Tandon, Gyaneshwar P; Baur, Jeffery W; Qi, H Jerry

    2016-04-01

    Cyclic loading conditions are commonly encountered in the applications of shape memory polymers (SMPs), where the cyclic characteristics of the materials determine their performance during the service life, such as deformation resistance, shape recovery speed and shape recovery ratio. Recent studies indicate that in addition to the physical damage or some other irreversible softening effects, the viscoelastic nature could also be another possible reason for the degraded cyclic behavior of SMPs. In this paper, we explore in detail the influence of the viscoelastic properties on the cyclic tension and shape memory (SM) behavior of an epoxy based amorphous thermosetting polymer. Cyclic experiments were conducted first, which show that although the epoxy material does not have any visible damage or irreversible softening effect during deformation, it still exhibits obvious degradation in the cyclic tension and SM behaviors. A linear multi-branched model is utilized to assist in the prediction and understanding of the mechanical responses of amorphous SMPs. Parametric studies based on the applied model suggest that the shape memory performance can be improved by adjusting programming and recovery conditions, such as lowering the loading rate, increasing the programming temperature, and reducing the holding time.

  2. The evolution of Momordica cyclic peptides.

    Science.gov (United States)

    Mahatmanto, Tunjung; Mylne, Joshua S; Poth, Aaron G; Swedberg, Joakim E; Kaas, Quentin; Schaefer, Hanno; Craik, David J

    2015-02-01

    Cyclic proteins have evolved for millions of years across all kingdoms of life to confer structural stability over their acyclic counterparts while maintaining intrinsic functional properties. Here, we show that cyclic miniproteins (or peptides) from Momordica (Cucurbitaceae) seeds evolved in species that diverged from an African ancestor around 19 Ma. The ability to achieve head-to-tail cyclization of Momordica cyclic peptides appears to have been acquired through a series of mutations in their acyclic precursor coding sequences following recent and independent gene expansion event(s). Evolutionary analysis of Momordica cyclic peptides reveals sites that are under selection, highlighting residues that are presumably constrained for maintaining their function as potent trypsin inhibitors. Molecular dynamics of Momordica cyclic peptides in complex with trypsin reveals site-specific residues involved in target binding. In a broader context, this study provides a basis for selecting Momordica species to further investigate the biosynthesis of the cyclic peptides and for constructing libraries that may be screened against evolutionarily related serine proteases implicated in human diseases. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Some Structure Properties of the Cyclic Fuzzy Group Family

    Institute of Scientific and Technical Information of China (English)

    Hacl Akta(s); Naim (C)a(g)man

    2005-01-01

    In crisp environment, the notion of cyclic group on a set is well known. We study an extension of this classical notion to the fuzzy sets to define the concept of cyclic fuzzy subgroups. By using these cyclic fuzzy subgroups, we then define a cyclic fuzzy group family and investigate its structure properties.

  4. [Nitric oxide and lipid peroxidation].

    Science.gov (United States)

    Cristol, J P; Maggi, M F; Guérin, M C; Torreilles, J; Descomps, B

    1995-01-01

    Nitric oxide (NO) is a free radical produced enzymatically in biological systems from the guanidino group of L-arginine. Its large spectrum of biological effects is achieved through chemical interactions with different targets including oxygen (O2), superoxide (O2o-) and other oxygen reactive species (ROS), transition metals and thiols. Superoxide anions and other ROS have been reported to react with NO to produce peroxynitrite anions that can decompose to form nitrogen dioxide (NO2) and hydroxyl radial (OHo). Thus, NO has been reported to have a dual effect on lipid peroxidation (prooxidant via the peroxynitrite or antioxydant via the chelation of ROS). In the present study we have investigated in different models the in vitro and in vivo action of NO on lipid peroxidation. Copper-induced LDL oxidation were used as an in vitro model. Human LDL (100 micrograms ApoB/ml) were incubated in oxygene-saturated PBS buffer in presence or absence of Cu2+ (2.5 microM) with increasing concentrations of NO donnors (sodium nitroprussiate or nitroso-glutathione). LDL oxidation was monitored continuously for conjugated diene formation (234 nm) and 4-hydroxynonenal (HNE) accumulation. Exogenous NO prevents in a dose dependent manner the progress of copper-induced oxidation. Ischaemia-reperfusion injury (I/R), characterized by an overproduction of ROS, is used as an in vivo model. Anaesthetized rats were submitted to 1 hour renal ischaemia following by 2 hours of reperfusion. Sham-operated rats (SOP) were used as control. Lipid peroxidation was evaluated by measuring the HNE accumulated in rats kidneys in presence or absence of L-arginine or D-arginine infusion. L-arginine, but not D-arginine, enhances HNE accumulation in I/R but not in SOP (< 0.050 pmol/g tissue in SOP versus 0.6 nmol/g tissue in I/R), showing that, in this experimental conditions, NO produced from L-arginine, enhances the toxicity of ROS. This study shows that the pro- or antioxydant effects of NO are different

  5. Lower Expression of SLC27A1 Enhances Intramuscular Fat Deposition in Chicken via Down-Regulated Fatty Acid Oxidation Mediated by CPT1A

    Science.gov (United States)

    Qiu, Fengfang; Xie, Liang; Ma, Jing-e; Luo, Wen; Zhang, Li; Chao, Zhe; Chen, Shaohao; Nie, Qinghua; Lin, Zhemin; Zhang, Xiquan

    2017-01-01

    Intramuscular fat (IMF) is recognized as the predominant factor affecting meat quality due to its positive correlation with tenderness, juiciness, and flavor. Chicken IMF deposition depends on the balance among lipid synthesis, transport, uptake, and subsequent metabolism, involving a lot of genes and pathways, however, its precise molecular mechanisms remain poorly understood. In the present study, the breast muscle tissue of female Wenchang chickens (WC) (higher IMF content, 1.24 in D120 and 1.62 in D180) and female White Recessive Rock chickens (WRR; lower IMF content, 0.53 in D120 and 0.90 in D180) were subjected to RNA-sequencing (RNA-seq) analysis. Results showed that many genes related to lipid catabolism, such as SLC27A1, LPL, ABCA1, and CPT1A were down-regulated in WC chickens, and these genes were involved in the PPAR signaling pathway and formed an IPA® network related to lipid metabolism. Furthermore, SLC27A1 was more down-regulated in WRR.D180.B than in WRR.D120.B. Decreased cellular triglyceride (TG) and up-regulated CPT1A were observed in the SLC27A1 overexpression QM-7 cells, and increased cellular triglyceride (TG) and down-regulated CPT1A were observed in the SLC27A1 knockdown QM-7 cells. These results suggest that lower lipid catabolism exists in WC chickens but not in WRR chickens, and lower expression of SLC27A1 facilitate IMF deposition in chicken via down-regulated fatty acid oxidation mediated by CPT1A. These findings indicate that reduced lipid catabolism, rather than increased lipid anabolism, contributes to chicken IMF deposition. PMID:28706492

  6. 21 CFR 868.5165 - Nitric oxide administration apparatus.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitric oxide administration apparatus. 868.5165... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5165 Nitric oxide administration apparatus. (a) Identification. The nitric oxide administration apparatus is a device used to add...

  7. Regulation of cyclic GMP, cyclic amp and lactate dehydrogenase by putative neutrotransmitters in the C6 rat glioma cell line

    Energy Technology Data Exchange (ETDEWEB)

    Bottenstein, J.E.; de Vellis, J.

    1977-01-01

    In C6 cells norepinephrine and dopamine caused transient increases in cyclic GMP and cyclic AMP, as well as an induction of lactate dehydrogenase. All of these responses were blocked by 1-propranolol, suggesting mediation by a ..beta..-receptor. Phentolamine potentiated the NE-increased cAMP levels by 5-fold when NE was used at suboptimal doses, suggesting the presence of ..cap alpha..-adrenergic receptors in C6 cells. Carbamylcholine decreased the levels of both cyclic nucleotides, with hexamethonium partially reversing the effect on cyclic GMP. Dibutyryl-cyclic GMP or carbamylcholine reduced catecholamine-induced cyclic AMP levels. Serotonin increased cyclic GMP levels 60% and decreased cyclic AMP levels 36%. Calcium- and magnesium-free media inhibited the norepinephrine-induced levels of cyclic GMP and cyclic AMP respectively.

  8. Regulation of cyclic GMP, cyclic AMP and lactate dehydrogenase by putative neurotransmitters in the C6 rat glioma cell line

    Energy Technology Data Exchange (ETDEWEB)

    Bottenstein, J.E.; de Vellis, J.

    1978-01-01

    In C6 cells norepinephrine and dopamine caused transient increases in cyclic GMP and cyclic AMP, as well as an induction of lactate dehydrogenase. All of these responses were blocked by l-propranolol, suggesting mediation by a ..beta..-receptor. Phentolamine potentiated the NE-increased cAMP levels by 5-fold when NE was used at suboptimal doses, suggesting the presence of ..cap alpha..-adrenergic receptors in C6 cells. Carbamylcholine decreased the levels of both cyclic nucleotides, with hexamethonium partially reversing the effect on cyclic GMP. Dibutyryl-cyclic GMP or carbamylcholine reduced catecholamine-induced cyclic AMP levels. Serotonin increased cyclic GMP levels 60% and decreased cyclic AMP levels 36%. Calcium- and magnesium-free media inhibited the norepinephrine-induced levels of cyclic GMP and cyclic AMP respectively.

  9. Cyclic nucleotides and mitogen-activated protein kinases: regulation of simvastatin in platelet activation

    Directory of Open Access Journals (Sweden)

    Hou Ssu-Yu

    2010-06-01

    Full Text Available Abstract Background 3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA reductase inhibitors (statins have been widely used to reduce cardiovascular risk. These statins (i.e., simvastatin may exert other effects besides from their cholesterol-lowering actions, including inhibition of platelet activation. Platelet activation is relevant to a variety of coronary heart diseases. Although the inhibitory effect of simvastatin in platelet activation has been studied; the detailed signal transductions by which simvastatin inhibit platelet activation has not yet been completely resolved. Methods The aim of this study was to systematically examine the detailed mechanisms of simvastatin in preventing platelet activation. Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance studies were used to assess the antiplatelet activity of simvastatin. Results Simvastatin (20-50 μM exhibited more-potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists (i.e., thrombin. Simvastatin inhibited collagen-stimulated platelet activation accompanied by [Ca2+]i mobilization, thromboxane A2 (TxA2 formation, and phospholipase C (PLCγ2, protein kinase C (PKC, and mitogen-activated protein kinases (i.e., p38 MAPK, JNKs phosphorylation in washed platelets. Simvastatin obviously increased both cyclic AMP and cyclic GMP levels. Simvastatin markedly increased NO release, vasodilator-stimulated phosphoprotein (VASP phosphorylation, and endothelial nitric oxide synthase (eNOS expression. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the simvastatin-mediated inhibitory effects on platelet aggregation, PLCγ2 and p38 MAPK phosphorylation, and simvastatin-mediated stimulatory effects on VASP and eNOS phosphorylation. Conclusion The most important findings of this study demonstrate for the first time that inhibitory effect of simvastatin in platelet activation may involve activation of the cyclic AMP-eNOS/NO-cyclic

  10. Prostaglandin E2 potentiates interferon-γ-induced nitric oxide production in cultured rat microglia.

    Science.gov (United States)

    Nagano, Takayuki; Nishiyama, Ryo; Sanada, Ayaka; Mutaguchi, Yukiko; Ioku, Anna; Umeki, Hirohisa; Kishimoto, Satoshi; Yamanaka, Daisuke; Kimura, Shinya H; Takemura, Motohiko

    2017-02-01

    Prostaglandin E2 (PGE2 ) plays crucial roles in managing microglial activation through the prostanoid EP2 receptor, a PGE2 receptor subtype. In this study, we report that PGE2 enhances interferon-γ (IFN-γ)-induced nitric oxide production in microglia. IFN-γ increased the release of nitrite, a metabolite of nitric oxide, which was augmented by PGE2 , although PGE2 by itself slightly affects nitrite release. The potentiating effect of PGE2 was positively associated with increased expression of inducible nitric oxide synthase. In contrast to nitrite release induced by IFN-γ, lipopolysaccharide-induced nitrite release was not affected by PGE2 . An EP2 agonist, ONO-AE1-259-01 also augmented IFN-γ-induced nitrite release, while an EP1 agonist, ONO-DI-004, an EP3 agonist, ONO-AE-248, or an EP4 agonist, ONO-AE1-329, did not. In addition, the potentiating effect of PGE2 was inhibited by an EP2 antagonist, PF-04418948, but not by an EP1 antagonist, ONO-8713, an EP3 antagonist, ONO-AE3-240, or an EP4 antagonist, ONO-AE3-208, at 10(-6)  M. Among the EP agonists, ONO-AE1-259-01 alone was able to accumulate cyclic adenosine monophosphate (AMP), and among the EP antagonists, PF-04418948 was the only one able to inhibit PGE2 -increased intracellular cyclic AMP accumulation. On the other hand, IFN-γ promoted phosphorylation of signal transducer and activator of transcription 1, which was not affected by PGE2 . Furthermore, other prostanoid receptor agonists, PGD2 , PGF2α , iloprost, and U-46119, slightly affected IFN-γ-induced nitrite release. These results indicate that PGE2 potentiates IFN-γ-induced nitric oxide production in microglia through the EP2 receptor, which may shed light on one of the pro-inflammatory aspects of PGE2 . © 2016 International Society for Neurochemistry.

  11. Cyclic Strain Enhances Cellular Uptake of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Jia Hu

    2015-01-01

    Full Text Available Nanoparticles (NPs have gained increasing interest in recent years due to their potential use as drug carrier, imaging, and diagnostic agents in pharmaceutical and biomedical applications. While many cells in vivo experience mechanical forces, little is known about the correlation of the mechanical stimulation and the internalization of NPs into cells. This paper investigates the effects of applied cyclic strain on NP uptake by cells. Bovine aortic endothelial cells (BAECs were cultured on collagen-coated culture plates and placed under cyclic equal-axial strains. NPs of sizes ranging from 50 to 200 nm were loaded at a concentration of 0.02 mg/mL and cyclic strains from 5 to 15% were applied to the cells for one hour. The cyclic strain results in a significant enhancement in NP uptake, which increases almost linearly with strain level. The enhanced uptake also depends on size of the NPs with the highest uptake observed on 100 nm NP. The effect of enhanced NP uptake lasts around 13 hours after cyclic stretch. Such in vitro cell stretch systems mimic physiological conditions of the endothelial cells in vivo and could potentially serve as a biomimetic platform for drug therapeutic evaluation.

  12. Cyclic transformation of orbital angular momentum modes

    CERN Document Server

    Schlederer, Florian; Fickler, Robert; Malik, Mehul; Zeilinger, Anton

    2015-01-01

    The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D-dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D-dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally enta...

  13. Cyclic transformation of orbital angular momentum modes

    Science.gov (United States)

    Schlederer, Florian; Krenn, Mario; Fickler, Robert; Malik, Mehul; Zeilinger, Anton

    2016-04-01

    The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D-dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D-dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally entangled Bell-states.

  14. CHANGES OF NITRIC OXIDE AND PROTECTIVE EFFECTS OF NITRIC OXIDE INHIBITORS IN NEWBORN RATS WITH SEPSIS

    Institute of Scientific and Technical Information of China (English)

    史源; 李华强; 潘捷; 沈际皋

    1995-01-01

    In a newborn rat model of sepsis, the changes of nitric oxide and the protective effects of methylene blue or/and dexaraethason were investigated. The results revealed that plasma nitric oxide levels were ele-cted at 6 h and peaked at 12 h after bacterial challenge. The treatment with methylene or/and dexam-etbasone was found to Munt hypoglycenua and hyperlacdcemla, to reduce the occurrence rate of loss ot re-sponse to pain, and to prolong the survival time. Moreover, therapy by dexamethasone was shown to de-crease the 24 h mortality. The results suggested that nitric coide play an important role during the course of fatal P. aeruginosa sepsis, hut it is clear that the clinical value of nitric oxide and its inhibitors need to be further studied.

  15. Circulating nitric oxide products do not solely reflect nitric oxide release in cirrhosis and portal hypertension

    DEFF Research Database (Denmark)

    Afzelius, Pia; Bazeghi, Nassim; Bie, Peter;

    2011-01-01

    Patients with cirrhosis often develop a systemic vasodilatation and a hyperdynamic circulation with activation of vasoconstrictor systems such as the renin-angiotensin-aldosterone system (RAAS), and vasopressin. Increased nitric oxide (NO) synthesis has been implicated in the development...

  16. Nitric oxide turnover in permeable river sediment

    DEFF Research Database (Denmark)

    Schreiber, Frank; Stief, Peter; Kuypers, Marcel M M

    2014-01-01

    We measured nitric oxide (NO) microprofiles in relation to oxygen (O2) and all major dissolved N-species (ammonium, nitrate, nitrite, and nitrous oxide [N2O]) in a permeable, freshwater sediment (River Weser, Germany). NO reaches peak concentrations of 0.13 μmol L-1 in the oxic zone and is consumed...

  17. Nitric Oxide in Mammary Tumor Progression

    Science.gov (United States)

    1998-07-01

    de Miguel L, Monton M, Casado S, Lopez -Farre A: Endothelial cytosolic proteins bind to the 3’-untranslated region of endothelial nitric oxide...Vazquez AM. Cabrera L, Barral AM, Gen- 38. Morgan DA, Ruscetti FW, Gallo R: Selective in vitro delman R, Jondal M: Toxic effects of interleukin-2

  18. Nitric Oxide Synthase Inhibitors as Antidepressants

    DEFF Research Database (Denmark)

    Wegener, Gregers; Volke, Vallo

    2010-01-01

    been suggested to play major roles in the pathophysiology of mood and stress-related disorders. However, a few clinical and several pre-clinical studies, strongly suggest involvement of the nitric oxide (NO) signaling pathway in these disorders. Moreover, several of the conventional neurotransmitters...

  19. Processes regulating nitric oxide emissions from soils

    DEFF Research Database (Denmark)

    Pilegaard, Kim

    2013-01-01

    Nitric oxide (NO) is a reactive gas that plays an important role in atmospheric chemistry by influencing the production and destruction of ozone and thereby the oxidizing capacity of the atmosphere. NO also contributes by its oxidation products to the formation of acid rain. The major sources...

  20. Nitric Oxide and the Central Nervous System

    NARCIS (Netherlands)

    E. Dzoljic (Eleonora)

    1998-01-01

    textabstractDuring the last ten years, several investigators have reported that biological effects of endothelium-derived relaxing factor (EDRF; Furchgott and Zawadzki, 1980) are actually activities of a signal molecule, nitric oxide (NO; Moncada el al., 1988). This molecule is synthesised by endoth

  1. Increased nitric oxide release and expression of endothelial and inducible nitric oxide synthases in mildly changed porcine mitral valve leaflets

    DEFF Research Database (Denmark)

    Moesgaard, Sophia G; Olsen, Lisbeth H; Viuff, Birgitte M

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: Little is known of the local role of nitric oxide (NO) in heart valves in relation to heart valve diseases. The study aim was to examine NO release and the expression of both endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) in re...

  2. Increased nitric oxide release and expression of endothelial and inducible nitric oxide synthases in mildly changed porcine mitral valve leaflets

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Olsen, Lisbeth Høier; Viuff, Birgitte;

    2007-01-01

    Background and aim of the study: Little is known of the local role of nitric oxide (NO) in heart valves in relation to heart valve diseases. The study aim was to examine NO release and the expression of both endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (i...

  3. Evaluation of homogeneous electrocatalysts by cyclic voltammetry.

    Science.gov (United States)

    Rountree, Eric S; McCarthy, Brian D; Eisenhart, Thomas T; Dempsey, Jillian L

    2014-10-06

    The pursuit of solar fuels has motivated extensive research on molecular electrocatalysts capable of evolving hydrogen from protic solutions, reducing CO2, and oxidizing water. Determining accurate figures of merit for these catalysts requires the careful and appropriate application of electroanalytical techniques. This Viewpoint first briefly presents the fundamentals of cyclic voltammetry and highlights practical experimental considerations before focusing on the application of cyclic voltammetry for the characterization of electrocatalysts. Key metrics for comparing catalysts, including the overpotential (η), potential for catalysis (E(cat)), observed rate constant (k(obs)), and potential-dependent turnover frequency, are discussed. The cyclic voltammetric responses for a general electrocatalytic one-electron reduction of a substrate are presented along with methods to extract figures of merit from these data. The extension of this analysis to more complex electrocatalytic schemes, such as those responsible for H2 evolution and CO2 reduction, is then discussed.

  4. Cyclic distillation technology - A mini-review

    DEFF Research Database (Denmark)

    Bîldea, Costin Sorin; Pătruţ, Cătălin; Jørgensen, Sten Bay;

    2016-01-01

    Process intensification in distillation systems has received much attention during the past decades, with the aim of increasing both energy and separation efficiency. Various techniques, such as internal heat-integrated distillation, membrane distillation, rotating packed bed, dividing-wall columns...... and reactive distillation were studied and reported in literature. All these techniques employ the conventional continuous counter-current contact of vapor and liquid phases. Cyclic distillation technology is based on an alternative operating mode using separate phase movement which leads to key practical...... advantages in both chemical and biochemical processes. This article provides a mini-review of cyclic distillation technology. The topics covered include the working principle, design and control methods, main benefits and limitations as well as current industrial applications. Cyclic distillation can...

  5. Cyclic Polymer with Alternating Monomer Sequence.

    Science.gov (United States)

    Zhu, Wen; Li, Zi; Zhao, Youliang; Zhang, Ke

    2015-11-01

    Cyclic polymers with alternating monomer sequence are synthesized for the first time based on the ring-closure strategy. Well-defined telechelic alternating polymers are synthesized by reversible addition-fragmentation chain transfer polymerization by copolymerizing the electron acceptor monomer of N-benzylmaleimide and donor monomer of styrene with a feed ratio of 1 between them. The corresponding cyclic alternating polymers are then produced by the UV-induced Diels-Alder click reaction to ring-close the linear alternating polymer precursors under highly diluted reaction solution.

  6. On cyclic associative Abel-Grassman groupoids

    OpenAIRE

    Iqbal, Muhammad; Ahmad, Imtiaz; Shah, Muhammad; Ali, Muhammad Irfan

    2015-01-01

    A new subclass of AG-groupoids, so called, cyclic associative Abel-Grassman groupoids or CA-AG-groupoid is studied. These have been enumerated up to order $6$. A test for the verification of cyclic associativity for an arbitrary AG-groupoid has been introduced. Various properties of CA-AG-groupoids have been studied. Relationship among CA-AG-groupoids and other subclasses of AG-groupoids is investigated. It is shown that the subclass of CA-AG-groupoid is different from that of the AG{*}-group...

  7. Undrained Cyclic Behaviour of Dense Frederikshavn Sand

    DEFF Research Database (Denmark)

    Nielsen, Søren Kjær; Ibsen, Lars Bo; Sørensen, Kris Wessel

    2013-01-01

    A modified contour diagram is created for the Frederikshavn Sand in the undrained case for a relative density of ID = 80 %. It can be used to estimate the number of cycles to failure for a given combination of pore pressure, average and cyclic load ratio. The diagram is based on a series of undra......A modified contour diagram is created for the Frederikshavn Sand in the undrained case for a relative density of ID = 80 %. It can be used to estimate the number of cycles to failure for a given combination of pore pressure, average and cyclic load ratio. The diagram is based on a series...

  8. Cyclic Entropy: An Alternative to Inflationary Cosmology

    CERN Document Server

    Frampton, Paul Howard

    2015-01-01

    We address how to construct an infinitely cyclic universe model. A major consideration is to make the entropy cyclic which requires the entropy to be reset to zero in each cycle expansion to turnaround, to contraction, to bounce, etc. Here we reset entropy at the turnaround by selecting the visible universe from the multiverse which is generated by the accelerated expansion. In the model, the observed homogeneity is explained by the low entropy at the bounce, The observed flatness arises from the contraction together with the reduction in size between the expanding and contracting universe. The present flatness is predicted to be very precise.

  9. Ultrafast cyclic voltammetry with asymmetrical potential scan

    Institute of Scientific and Technical Information of China (English)

    Zhi Yong Guo; Xiang Qin Lin

    2008-01-01

    Based on the perfect ohmic drop compensation by online electronic positive feedback, ultrafast cyclic voltammetry withasymmetrical potential scan is achieved for the first time, with the reduction of anthracene acting as the test system. Compared withthe traditional cyclic voltammetry utilizing symmetrical triangular waveform as the excitation one, the new method allows a simplerapproach to mechanistic analysis of ultrafast chemical reactions coupled with a charge transfer. And perhaps more important, it alsoprovides a way to eliminate the interference of the adsorbed product in dynamic monitoring.

  10. Severe congenital cyclic neutropenia: A case report

    Science.gov (United States)

    Patil, Vidyavathi H; Hugar, Shivayogi M; Balikai, Girish; Patil, Sudha

    2016-01-01

    Congenital cyclic neutropenia syndrome is a constitutional genetic disorder which is characterized by very low number of neutrophils (neutropenia). Patients suffering from this disorder clinically present with neutropenia at early age, history of recurrent fever, ulcerations in the oral cavity, gingivitis, and other recurrent infections. This paper describes a case report of a child with recurrent mouth ulcers, fever, and later diagnosed with severe congenital cyclic neutropenia. This also emphasizes the importance of identification of rare causes of immunosuppressive conditions in children presenting with recurrent oral ulcers and poor dental hygiene, to prevent long-term complications of oral cavity and also morbidity and mortality secondary to neutropenic sepsis. PMID:27857902

  11. Development of a design methodology for high temperature cyclic applications of materials which experience cyclic softening

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L.; Stubbins, J.F. (Illinois Univ., Urbana, IL (USA). Dept. of Mechanical and Industrial Engineering)

    1988-12-01

    The project has as its original focus the high temperature behavior of 2.25 Cr-1 Mo steel, heat treated to produce a predominantly bainitic microstructure and the load carrying response of components made of this material. Experiments were carried out on uniform and notched specimens under both steady and cyclic loading using specially acquired electromechanical test machines. It emerged that a very important feature of mechanical behavior under the conditions of interest was the strong tendency of this material to cyclically soften, particularly at high temperature in the creep range, giving the illusion of a severe creep-fatigue interaction under certain conditions. This finding led to a significant component of the project being devoted to investigation of the effects of local, as opposed to generalized, cyclic softening, and the implications this phenomenon might have on the setting of allowable design stress limits. The format of this report is as follows: The second chapter is a review of the work carried out in approximately chronological order under the headings of work was carried out under the following: (1) 2.25 Cr 1 Mo Steel -- Elevated Temperature Fatigue and Environmental Effects; (2) Preliminary Studies of Advanced Austenitics; (3) A Uniaxial Constitutive Model for Cyclic Softening; (4) The Iso-Cyclic Stress-Strain Approach to Evaluation of Components in Cyclic Softening Materials; (5) Testing of High Temperature Austenitic Alloys; and (6) Design Methodology for Aging Materials -- Application to Cyclic Softening. 65 refs., 39 figs., 7 tabs.

  12. Co-crystal structures of PKG Iβ (92-227 with cGMP and cAMP reveal the molecular details of cyclic-nucleotide binding.

    Directory of Open Access Journals (Sweden)

    Jeong Joo Kim

    Full Text Available Cyclic GMP-dependent protein kinases (PKGs are central mediators of the NO-cGMP signaling pathway and phosphorylate downstream substrates that are crucial for regulating smooth muscle tone, platelet activation, nociception and memory formation. As one of the main receptors for cGMP, PKGs mediate most of the effects of cGMP elevating drugs, such as nitric oxide-releasing agents and phosphodiesterase inhibitors which are used for the treatment of angina pectoris and erectile dysfunction, respectively.We have investigated the mechanism of cyclic nucleotide binding to PKG by determining crystal structures of the amino-terminal cyclic nucleotide-binding domain (CNBD-A of human PKG I bound to either cGMP or cAMP. We also determined the structure of CNBD-A in the absence of bound nucleotide. The crystal structures of CNBD-A with bound cAMP or cGMP reveal that cAMP binds in either syn or anti configurations whereas cGMP binds only in a syn configuration, with a conserved threonine residue anchoring both cyclic phosphate and guanine moieties. The structure of CNBD-A in the absence of bound cyclic nucleotide was similar to that of the cyclic nucleotide bound structures. Surprisingly, isothermal titration calorimetry experiments demonstrated that CNBD-A binds both cGMP and cAMP with a relatively high affinity, showing an approximately two-fold preference for cGMP.Our findings suggest that CNBD-A binds cGMP in the syn conformation through its interaction with Thr193 and an unusual cis-peptide forming residues Leu172 and Cys173. Although these studies provide the first structural insights into cyclic nucleotide binding to PKG, our ITC results show only a two-fold preference for cGMP, indicating that other domains are required for the previously reported cyclic nucleotide selectivity.

  13. Mutations of PKA cyclic nucleotide-binding domains reveal novel aspects of cyclic nucleotide selectivity.

    Science.gov (United States)

    Lorenz, Robin; Moon, Eui-Whan; Kim, Jeong Joo; Schmidt, Sven H; Sankaran, Banumathi; Pavlidis, Ioannis V; Kim, Choel; Herberg, Friedrich W

    2017-07-06

    Cyclic AMP and cyclic GMP are ubiquitous second messengers that regulate the activity of effector proteins in all forms of life. The main effector proteins, the 3',5'-cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and the 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG), are preferentially activated by cAMP and cGMP, respectively. However, the molecular basis of this cyclic nucleotide selectivity is still not fully understood. Analysis of isolated cyclic nucleotide-binding (CNB) domains of PKA regulatory subunit type Iα (RIα) reveals that the C-terminal CNB-B has a higher cAMP affinity and selectivity than the N-terminal CNB-A. Here, we show that introducing cGMP-specific residues using site-directed mutagenesis reduces the selectivity of CNB-B, while the combination of two mutations (G316R/A336T) results in a cGMP-selective binding domain. Furthermore, introducing the corresponding mutations (T192R/A212T) into the PKA RIα CNB-A turns this domain into a highly cGMP-selective domain, underlining the importance of these contacts for achieving cGMP specificity. Binding data with the generic purine nucleotide 3',5'-cyclic inosine monophosphate (cIMP) reveal that introduced arginine residues interact with the position 6 oxygen of the nucleobase. Co-crystal structures of an isolated CNB-B G316R/A336T double mutant with either cAMP or cGMP reveal that the introduced threonine and arginine residues maintain their conserved contacts as seen in PKG I CNB-B. These results improve our understanding of cyclic nucleotide binding and the molecular basis of cyclic nucleotide specificity. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  14. Pore-forming bacterial toxins potently induce release of nitric oxide in porcine endothelial cells

    Science.gov (United States)

    1993-01-01

    Nitric oxide (NO) is believed to play an important role in sepsis- related hypotension. We examined the effects of two pore-forming bacterial exotoxins, Escherichia coli hemolysin and Staphylococcus aureus alpha-toxin, on NO formation in cultured porcine pulmonary artery endothelial cells. NO was quantified using a difference- spectrophotometric method based on the rapid and stoichiometric reaction of NO with oxyhemoglobin. Endothelial cyclic guanosine monophosphate levels were also monitored. Both exotoxins increased NO synthesis in endothelial cells in a time- and dose-dependent manner to an extent exceeding that observed with the ionophore A23187 or thrombin. The capacity of exotoxins to induce NO formation may be relevant in patients with severe local or systemic bacterial infections. PMID:8391061

  15. Familial hemiplegic migraine type 1 shows no hypersensitivity to nitric oxide

    DEFF Research Database (Denmark)

    Hansen, J.M.; Thomsen, L.L.; Olesen, J.

    2008-01-01

    Familial hemiplegic migraine type 1 (FHM-1) is a dominantly inherited subtype of migraine with aura and transient hemiplegia associated with mutations in the CACNA1A gene. FHM-1 shares many phenotypical similarities with common types of migraine, indicating common neurobiological pathways....... Experimental studies have established that activation of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a crucial role in migraine pathophysiology. Therefore, we tested the hypothesis that CACNA1A mutations in patients with FHM-1 are associated with hypersensitivity to NO-cGMP pathway...... (V-meanMCA) by transcranial Doppler; diameter of the superficial temporal artery (STA) by Dermascan. One patient reported migraine without aura 5 h after start of the GTN infusion. No aura was reported. The AUC(headache) in the immediate phase was more pronounced in patients than in controls (P = 0...

  16. Monitoring of the tumor response to nano-graphene oxide-mediated photothermal/photodynamic therapy by diffusion-weighted and BOLD MRI

    Science.gov (United States)

    Cao, Jianbo; An, Hengqing; Huang, Xinglu; Fu, Guifeng; Zhuang, Rongqiang; Zhu, Lei; Xie, Jin; Zhang, Fan

    2016-05-01

    Photothermal therapy (PTT) and photodynamic therapy (PDT) are promising cancer treatment modalities. Because each modality has its own set of advantages and limitations, there has been interest in developing methods that can co-deliver the two regimens for enhanced tumor treatment. Among the efforts, nano-graphene oxide-mediated phototherapies have recently attracted much attention. Nano-graphene oxide has a broad absorbance spectrum and can be loaded with photosensitizers, such as chlorin e6, with high efficiency. Chlorin e6-loaded and PEGylated nano-graphene (GO-PEG-Ce6) can be excited at 660 nm, 808 nm, or both, to induce PDT, PTT, or PDT/PTT combination. Despite the potential of the treatments, there is a lack of a diagnostic tool which can monitor their therapeutic response in a non-invasive and prognostic manner; such an ability is urgently needed for the transformation and translation of the technologies. In this study, we performed diffusion-weighted and blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) after GO-PEG-Ce6-mediated PTT, PDT, or PTT/PDT. We found that after efficient PTT, there is a significant increase of the tumor apparent diffusion coefficient (ADC) value in diffusion-weighted imaging (DWI) maps; meanwhile, an efficient PDT led to an increase of in BOLD images. In both the cases, the amplitude of the increase was correlated with the treatment outcomes. More interestingly, a synergistic treatment efficacy was observed when the PTT/PDT combination was applied, and the combination was associated with a greater ADC and increase than when either modality was used alone. In particular, the PTT/PDT condition that induced the most dramatic short-term increase of the ADC value (>70%) caused the most effective tumor control in the long-run, with 60% of the treated animals being tumor-free after 60 days. These results suggest the great promise of the combination of DWI and BOLD MRI as a tool for accurate monitoring and prognosis

  17. The coefficient of cyclic variation: a novel statistic to measure the magnitude of cyclic variation.

    Science.gov (United States)

    Fulford, Anthony Jc

    2014-01-01

    PERIODIC OR CYCLIC DATA OF KNOWN PERIODICITY ARE FREQUENTLY ENCOUNTERED IN EPIDEMIOLOGICAL AND BIOMEDICAL RESEARCH: for instance, seasonality provides a useful experiment of nature while diurnal rhythms play an important role in endocrine secretion. There is, however, little consensus on how to analysis these data and less still on how to measure association or effect size for the often complex patterns seen. A simple statistic, readily derived from Fourier regression models, provides a readily-understood measure cyclic variation in a wide variety of situations. The coefficient of cyclic variation or similar statistics derived from the variance of a Fourier series could provide a universal means of summarising the magnitude of periodic variation.

  18. Cyclic Plastic Deformation and Welding Simulation

    NARCIS (Netherlands)

    Ten Horn, C.H.L.J.

    2003-01-01

    One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose anal

  19. Cyclic viscoelastoplasticity of polypropylene/nanoclay composites

    DEFF Research Database (Denmark)

    Drozdov, A.; Christiansen, Jesper de Claville

    2012-01-01

    Observations are reported on isotactic polypropylene/organically modified nanoclay hybrids with concentrations of filler ranging from 0 to 5 wt.% in cyclic tensile tests with a stress–controlled program (oscillations between various maximum stresses and the zero minimum stress). A pronounced effect...

  20. Strongly Cyclic and Strongly Irreducible Decomposition

    Institute of Scientific and Technical Information of China (English)

    纪友清; 韩黎明

    2001-01-01

    Let W be an injective unilateral weighted shift, and let W(n) be the orthogonal direct sum of n copies of W. In this paper, we prove that, if the commutant of W is strictly cyclic, then W(n) has a unique (SI) decomposition with respect to similarity for every natural number n.

  1. Cyclic Triaxial Loading of Cohesionless Silty Sand

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2015-01-01

    To engineer efficient structures offshore, we need to extend our knowledge of soil response. Cyclic loading and high water pressure encountered offshore greatly influence cohesionless soil performance. Silty sand from Frederikshavn wind turbine farm was tested using single diameter height samples...

  2. Cyclic electron flow: facts and hypotheses.

    Science.gov (United States)

    Finazzi, Giovanni; Johnson, Giles N

    2016-09-01

    Over the last 15 years, research into the process of cyclic electron flow in photosynthesis has seen a huge resurgence. Having been considered by some in the early 1990s as a physiologically unimportant artefact, it is now recognised as essential to normal plant growth. Here, we provide an overview of the major developments covered in this special issue of photosynthesis research.

  3. Monopod bucket foundations under cyclic lateral loading

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    The monopod bucket foundation can be a cost-reducing sub-structure for offshore wind turbines. To avoid problems during the turbine operation, the long-term effect of cyclic loading must be considered in the design of the foundation. In this paper a 1g testing rig is adopted to extend the knowled...

  4. Monopod Bucket Foundations Under Cyclic Lateral Loading

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    2016-01-01

    The monopod bucket foundation has the potential to become a cost-reducing substructure for offshore wind turbines. To avoid problems during the energy converter operation, the long-term effect of cyclic loading must be considered in the design of the foundation. In this paper, a 1-g testing rig i...

  5. A New Cyclic Peptide from Schnabelia tetradonta

    Institute of Scientific and Technical Information of China (English)

    Hui DOU; Yan ZHOU; Shu lin PENG; Li Sheng DING

    2003-01-01

    A new cyclic octapeptide (schnabepeptide B) was isolated from the aerial part ofSchnabelia tetradonta (Sun) C. Y. Wu et C. Chen (Lamiaceae). Its structure was elucidated ascyclo-(NH-Trp-Gly1-Leu1-Gly2-Pro1-Pro2-Leu2-Pro3-CO) on the basis of extensive 2D NMR andMS spectra.

  6. Steady state oxygen reduction and cyclic voltammetry

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Karlberg, Gustav; Jaramillo, Thomas;

    2008-01-01

    The catalytic activity of Pt and Pt3Ni for the oxygen reduction reaction is investigated by applying a Sabatier model based on density functional calculations. We investigate the role of adsorbed OH on the activity, by comparing cyclic voltammetry obtained from theory with previously published...

  7. Hopf Algebroids and Their Cyclic Theory

    NARCIS (Netherlands)

    Kowalzig, N.

    2009-01-01

    The main objective of this thesis is to clarify concepts of generalised symmetries in noncommutative geometry (i.e., the noncommutative analogue of groupoids and Lie algebroids) and their associated (co)homologies. These ideas are incorporated by the notion of Hopf algebroids and Hopf-cyclic (co)hom

  8. Cyclic Cratonic Carbonates and Phanerozoic Calcite Seas.

    Science.gov (United States)

    Wilkinson, Bruce H.

    1982-01-01

    Discusses causes of cyclicity in cratonic carbonate sequences and evidence for and potential significance of postulated primary calcite sediment components in past Paleozoic seas, outlining problems, focusing on models explaining existing data, and identifying background. Future sedimentary geologists will need to address these and related areas…

  9. STUDY OF CYCLIC AMP IN HUMAN SEMEN

    Institute of Scientific and Technical Information of China (English)

    JIANGNing

    1989-01-01

    It had been observed that there was a close relationship between cyclic AMP and the motility, energy metabolism, capaeitation and acrosome reaction of spermatozoa. In this study a radio-immunoassay procedure for measuring cAMP concentration in sperm and

  10. Scale invariant density perturbations from cyclic cosmology

    Science.gov (United States)

    Frampton, Paul Howard

    2016-04-01

    It is shown how quantum fluctuations of the radiation during the contraction era of a comes back empty (CBE) cyclic cosmology can provide density fluctuations which re-enter the horizon during the subsequent expansion era and at lowest order are scale invariant, in a Harrison-Zel’dovich-Peebles sense. It is necessary to be consistent with observations of large scale structure.

  11. Hopf Algebroids and Their Cyclic Theory

    NARCIS (Netherlands)

    Kowalzig, N.|info:eu-repo/dai/nl/304349755

    2009-01-01

    The main objective of this thesis is to clarify concepts of generalised symmetries in noncommutative geometry (i.e., the noncommutative analogue of groupoids and Lie algebroids) and their associated (co)homologies. These ideas are incorporated by the notion of Hopf algebroids and Hopf-cyclic

  12. Nitric oxide signalling and neuronal nitric oxide synthase in the heart under stress [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Yin Hua Zhang

    2017-05-01

    Full Text Available Nitric oxide (NO is an imperative regulator of the cardiovascular system and is a critical mechanism in preventing the pathogenesis and progression of the diseased heart. The scenario of bioavailable NO in the myocardium is complex: 1 NO is derived from both endogenous NO synthases (endothelial, neuronal, and/or inducible NOSs [eNOS, nNOS, and/or iNOS] and exogenous sources (entero-salivary NO pathway and the amount of NO from exogenous sources varies significantly; 2 NOSs are located at discrete compartments of cardiac myocytes and are regulated by distinctive mechanisms under stress; 3 NO regulates diverse target proteins through different modes of post-transcriptional modification (soluble guanylate cyclase [sGC]/cyclic guanosine monophosphate [cGMP]/protein kinase G [PKG]-dependent phosphorylation, S-nitrosylation, and transnitrosylation; 4 the downstream effectors of NO are multidimensional and vary from ion channels in the plasma membrane to signalling proteins and enzymes in the mitochondria, cytosol, nucleus, and myofilament; 5 NOS produces several radicals in addition to NO (e.g. superoxide, hydrogen peroxide, peroxynitrite, and different NO-related derivatives and triggers redox-dependent responses. However, nNOS inhibits cardiac oxidases to reduce the sources of oxidative stress in diseased hearts. Recent consensus indicates the importance of nNOS protein in cardiac protection under pathological stress. In addition, a dietary regime with high nitrate intake from fruit and vegetables together with unsaturated fatty acids is strongly associated with reduced cardiovascular events. Collectively, NO-dependent mechanisms in healthy and diseased hearts are better understood and shed light on the therapeutic prospects for NO and NOSs in clinical applications for fatal human heart diseases.

  13. Cyclic-di-GMP and cyclic-di-AMP activate the NLRP3 inflammasome

    OpenAIRE

    Abdul-Sater, Ali A.; Tattoli, Ivan; Jin, Lei; Grajkowski, Andrzej; Levi, Assaf; Koller, Beverly H.; Irving C Allen; Beaucage, Serge L.; Fitzgerald, Katherine A.; Ting, Jenny P.-Y.; Cambier, John C.; Stephen E Girardin; Schindler, Christian

    2013-01-01

    Cyclic dinucleotides have been recently shown to induce type I interferon secretion. This study shows they also activate the NLRP3 inflammasome to stimulate robust IL-1b secretion through a novel pathway that does not generate mitochondrial ROS.

  14. Speciation in aqueous solutions of nitric acid.

    Science.gov (United States)

    Hlushak, S; Simonin, J P; De Sio, S; Bernard, O; Ruas, A; Pochon, P; Jan, S; Moisy, P

    2013-02-28

    In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approximation (BiMSA), or associative MSA (AMSA), in which the size and the charge of the ions in the chemical pair may differ from those of the free ions. A simultaneous fit of the osmotic coefficient and of the proportion of free ions (obtained from Raman spectroscopy experiments) led to an estimation of the speciation in nitric acid solutions. The result obtained using this procedure was compared with the estimation obtained from the Raman experiments.

  15. Alternative to Nitric Acid Passivation Project Overview

    Science.gov (United States)

    Lewis, Pattie L.

    2013-01-01

    The standard practice for protection of stainless steel is a process called passivation. This procedure results in the formation of a metal oxide layer to prevent corrosion. Typical passivation procedures call for the use of nitric acid which exhibits excellent corrosion performance; however, there are a number of environmental, worker safety, and operational issues associated with its use. The longtime military specification for the passivation of stainless steel was cancelled in favor of newer specifications which allow for the use of citric acid in place of nitric acid. Citric acid offers a variety of benefits that include increased safety for personnel, reduced environmental impact, and reduced operational costs. There have been few studies, however, to determine whether citric acid is an acceptable alternative for NASA and DoD. This paper details activities to date including development of the joint test plan, on-going and planned testing, and preliminary results.

  16. Endothelial nitric oxide synthase in the microcirculation.

    Science.gov (United States)

    Shu, Xiaohong; Keller, T C Stevenson; Begandt, Daniela; Butcher, Joshua T; Biwer, Lauren; Keller, Alexander S; Columbus, Linda; Isakson, Brant E

    2015-12-01

    Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells.

  17. TRPV1 and TRPA1 mediate peripheral nitric oxide-induced nociception in mice.

    Directory of Open Access Journals (Sweden)

    Takashi Miyamoto

    Full Text Available Nitric oxide (NO can induce acute pain in humans and plays an important role in pain sensitization caused by inflammation and injury in animal models. There is evidence that NO acts both in the central nervous system via a cyclic GMP pathway and in the periphery on sensory neurons through unknown mechanisms. It has recently been suggested that TRPV1 and TRPA1, two polymodal ion channels that sense noxious stimuli impinging on peripheral nociceptors, are activated by NO in heterologous systems. Here, we investigate the relevance of this activation. We demonstrate that NO donors directly activate TRPV1 and TRPA1 in isolated inside-out patch recordings. Cultured primary sensory neurons display both TRPV1- and TRPA1-dependent responses to NO donors. BH4, an essential co-factor for NO production, causes activation of a subset of DRG neurons as assayed by calcium imaging, and this activation is at least partly dependent on nitric oxide synthase activity. We show that BH4-induced calcium influx is ablated in DRG neurons from TRPA1/TRPV1 double knockout mice, suggesting that production of endogenous levels of NO can activate these ion channels. In behavioral assays, peripheral NO-induced nociception is compromised when TRPV1 and TRPA1 are both ablated. These results provide genetic evidence that the peripheral nociceptive action of NO is mediated by both TRPV1 and TRPA1.

  18. Nitric oxide signals postovulatory aging-induced abortive spontaneous egg activation in rats.

    Science.gov (United States)

    Premkumar, Karuppanan V; Chaube, Shail K

    2015-07-01

    The aim of this study was to determine whether an increase of intracellular nitric oxide (NO) level signals postovulatory aging-induced abortive spontaneous egg activation (SEA) in rats. Freshly ovulated eggs (arrested at metaphase-II stage; M-II) were cultured in vitro for 3 hours to induce postovulatory egg aging. The morphological changes, inducible nitric oxide synthase (iNOS) expression, NO, cytosolic free Ca(2+), 3',5' cyclic guanosine monophosphate (cGMP), cell division cycle 25B (Cdc25B) and Wee1 levels, specific phosphorylation (pThr-14/Tyr-15) as well as total cyclin-dependent kinases-1 (Cdk1) (PSTAIRE) levels were analyzed. Postovulatory aging induced generation of NO possibly through an iNOS-mediated pathway. The increase in NO level was associated with augmented cytosolic free Ca(2+) as well as cGMP levels in aged eggs. A significant increase in Wee1 level and decrease of Cdc25B level were observed in aged eggs. An accumulation of phosphorylated Cdk1 (pThr-14/Tyr-15) level was observed in aged eggs, while total Cdk1 (PSTAIR) level remained unchanged. Our study demonstrates that generation of NO through an iNOS-mediated pathway increases cytosolic free Ca2+and cGMP levels. High levels of these signal molecules trigger the accumulation of phosphorylated Cdk1 in aged eggs. Thus, NO signals the accumulation of phosphorylated Cdk1 and induces postovulatory aging-induced abortive SEA in the rat.

  19. Autoxidation kinetics of aqueous nitric oxide

    OpenAIRE

    1993-01-01

    Reports on the kinetics of the autoxidation of aqueous nitric oxide are discussed. It is concluded that the correct rate law is -d[NO]/dt = 4kaq[NO]2 [O2] with kaq = 2 × 106 M-2 · s-1 at 25°C and that a recent report of a rate law zero order in NO is incorrect. © 1993.

  20. Nitric Oxide Scavenging by Red Cell Microparticles

    OpenAIRE

    Liu, Chen; Zhao, Weixin; George J Christ; Gladwin, Mark T.; Kim-Shapiro, Daniel B.

    2013-01-01

    Red cell microparticles form during the storage of red blood cells and in diseases associated with red cell breakdown and asplenia, including hemolytic anemias such as sickle cell disease. These small phospholipid vesicles that are derived from red blood cells have been implicated in the pathogenesis of transfusion of aged stored blood and hemolytic diseases, via activation of the hemostatic system and effects on nitric oxide (NO) bioavailability. Red cell microparticles react with the import...

  1. Expression and distribution of key enzymes of the cyclic GMP signaling in the human clitoris: relation to phosphodiesterase type 5 (PDE5).

    Science.gov (United States)

    Ückert, S; Oelke, M; Albrecht, K; Breitmeier, D; Kuczyk, M A; Hedlund, P

    2011-01-01

    The clitoris contributes to the normal female sexual response cycle. A significance of cyclic guanosine monophosphate (GMP) has been assumed in the control of clitoral vascular smooth muscle. As only a few investigations on the physiology of the vascular and non-vascular clitoral tissue have been carried out, knowledge on the mechanisms controlling this particular female genital organ is still vague. It has been suggested that human clitoral corpus cavernosum smooth muscle is regulated by nitric oxide (NO)/cyclic GMP and related key enzymes, such as NO synthases (NOSs) and the phosphodiesterase type 5 (PDE5). The present study evaluated in the human clitoris, by means of immunohistochemistry, the expression and distribution of key enzymes of the cyclic GMP pathway, such as the endothelial NOS, PDE2, PDE11 and cyclic GMP-dependent protein kinase type I (cGKI) in relation to the PDE5. Immunohistochemistry revealed the presence of PDE2, PDE5 and cGKI in the smooth muscle wall of blood vessels transversing the supepithelial and stromal space. Immunosignals specific for PDE2 were also identified in interstitial-like cells located in the basal epithelial layer. Staining for PDE11A was observed in single nerve trunks located in the clitoral stroma. The results are in favor of a role of the cyclic GMP signaling in the control of clitoral blood flow. It seems likely that PDE2 and PDE11 are also involved in the mechanism of local (neuro)transmission in the clitoris.

  2. Oxygen, nitric oxide and articular cartilage

    Directory of Open Access Journals (Sweden)

    B Fermor

    2007-04-01

    Full Text Available Molecular oxygen is required for the production of nitric oxide (NO, a pro-inflammatory mediator that is associated with osteoarthritis and rheumatoid arthritis. To date there has been little consideration of the role of oxygen tension in the regulation of nitric oxide production associated with arthritis. Oxygen tension may be particularly relevant to articular cartilage since it is avascular and therefore exists at a reduced oxygen tension. The superficial zone exists at approximately 6% O2, while the deep zone exists at less than 1% O2. Furthermore, oxygen tension can alter matrix synthesis, and the material properties of articular cartilage in vitro.The increase in nitric oxide associated with arthritis can be caused by pro-inflammatory cytokines and mechanical stress. Oxygen tension significantly alters endogenous NO production in articular cartilage, as well as the stimulation of NO in response to both mechanical loading and pro-inflammatory cytokines. Mechanical loading and pro-inflammatory cytokines also increase the production of prostaglandin E2 (PGE2. There is a complex interaction between NO and PGE2, and oxygen tension can alter this interaction. These findings suggest that the relatively low levels of oxygen within the joint may have significant influences on the metabolic activity, and inflammatory response of cartilage as compared to ambient levels. A better understanding of the role of oxygen in the production of inflammatory mediators in response to mechanical loading, or pro-inflammatory cytokines, may aid in the development of strategies for therapeutic intervention in arthritis.

  3. SCATTERING BY CYCLIC POLYMERS AND COPOLYMERS AT LARGE SCATTERING VECTORS

    NARCIS (Netherlands)

    KOSMAS, M; BENOIT, H; HADZIIOANNOU, G

    1994-01-01

    General formulae allowing the evaluation of the form factors of cyclic block copolymers are established and graphs for cyclic copolymers of the form (A-B)(N) are shown. When N is large, the linear and the cyclic copolymer have the same behaviour. It is possible to extend at large angle an analytical

  4. Cyclic cocycles on deformation quantizations and higher index theorems

    NARCIS (Netherlands)

    Pflaum, M.J.; Posthuma, H.; Tang, X.

    2010-01-01

    We construct a nontrivial cyclic cocycle on the Weyl algebra of a symplectic vector space. Using this cyclic cocycle we construct an explicit, local, quasi-isomorphism from the complex of differential forms on a symplectic manifold to the complex of cyclic cochains of any formal deformation quantiza

  5. SCATTERING BY CYCLIC POLYMERS AND COPOLYMERS AT LARGE SCATTERING VECTORS

    NARCIS (Netherlands)

    KOSMAS, M; BENOIT, H; HADZIIOANNOU, G

    1994-01-01

    General formulae allowing the evaluation of the form factors of cyclic block copolymers are established and graphs for cyclic copolymers of the form (A-B)(N) are shown. When N is large, the linear and the cyclic copolymer have the same behaviour. It is possible to extend at large angle an analytical

  6. Transient Spectroscopic Properties of [60]Fullerene-Containing Cyclic Sulphoxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The properties of the triplet excited state of [60]fullerene-containing cyclic sulphoxide have been investigated by time-resolved absorption spectroscopy. Transient absorption bands of [60]fullerene-containing cyclic sulphoxide showed two decay-components, which were attributed to triplet excited states of different spin multiplicity. The properties of photoexcited states of [60]fullerene-containing cyclic sulphoxide are also reported.

  7. Cyclic cocycles on deformation quantizations and higher index theorems

    NARCIS (Netherlands)

    Pflaum, M.J.; Posthuma, H.; Tang, X.

    2010-01-01

    We construct a nontrivial cyclic cocycle on the Weyl algebra of a symplectic vector space. Using this cyclic cocycle we construct an explicit, local, quasi-isomorphism from the complex of differential forms on a symplectic manifold to the complex of cyclic cochains of any formal deformation

  8. Expression of nitric oxide synthase and guanylate cyclase in the human ciliary body and trabecular meshwork

    Institute of Scientific and Technical Information of China (English)

    WU Ren-yi; MA Ning

    2012-01-01

    Background The role played by the nitric oxide (NO) signaling pathway in the aqueous humor dynamics is still unclear.This study was designed to investigate the expression and distribution of NO synthase (NOS) isoforms and guanylate cyclase (GC) in human ciliary body,trabecular meshwork and the Schlemm's canal.Methods Twelve eyes after corneal transplantation were used.Expression of three NOS isoforms (i.e.neuronal NOS (nNOS),inducible NOS (iNOS) and endothelial NOS (eNOS)) and GC were assessed in 10 eyes by immunohistochemical staining using monoclonal or polyclonal antibody of NOS and GC.Ciliary bodies were dissected free and the total proteins were extracted.Western blotting was performed to confirm the protein expression of 3 NOS isoforms and GC.Results Expression of 3 NOS isoforms and GC were observed in the ciliary epithelium,ciliary muscle,trabecular meshwork and the endothelium of the Schlemm's canal.Immunoreactivity of nNOS was detected mainly along the apical cytoplasmic junction of the non-pigmented epithelium (NPE) and pigmented epithelial (PE) cells.Protein expressions of 3 NOS isoforms and GC were confirmed in isolated human ciliary body by Western blotting.Conclusions The expression of NOS isoforms and GC in human ciliary body suggest the possible involvement of NO and cyclic guanosine monophosphate (cyclic GMP,cGMP) signaling pathway in the ciliary body,and may play a role in both processes of aqueous humor formation and drainage.

  9. Updated role of nitric oxide in disorders of erythrocyte function.

    Science.gov (United States)

    Kahn, Marc J; Maley, Jason H; Lasker, George F; Kadowitz, Philip J

    2013-03-01

    Nitric oxide is a potent vasodilator that plays a critical role in disorders of erythrocyte function. Sickle cell disease, paroxysmal nocturnal hemoglobinuria and banked blood preservation are three conditions where nitric oxide is intimately related to dysfunctional erythrocytes. These conditions are accompanied by hemolysis, thrombosis and vasoocclusion. Our understanding of the interaction between nitric oxide, hemoglobin, and the vasculature is constantly evolving, and by defining this role we can better direct trials aimed at improving the treatments of disorders of erythrocyte function. Here we briefly discuss nitric oxide's interaction with hemoglobin through the hypothesis regarding Snitrosohemoglobin, deoxyhemoglobin, and myoglobin as nitrite reductases. We then review the current understanding of the role of nitric oxide in sickle cell disease, paroxysmal nocturnal hemoglobinuria, and banked blood, and discuss therapeutics in development to target nitric oxide in the treatment of some of these disorders.

  10. Electrochemical reduction of oxygen and nitric oxide at low temperature on La1−xSrxMnO3+δ cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2013-01-01

    Six La1−xSrxMnO3+δ (x=0, 0.05, 0.15, 0.25, 0.35, 0.50) perovskites were synthesised and characterised by powder XRD and cyclic voltammetry on cone-shaped electrodes in 10% oxygen in argon or 1% nitric oxide in argon at 200, 300 and 400°C. The activity of the manganite based perovskites were highest...

  11. Helical Two-Revolutional Cyclical Surface

    Directory of Open Access Journals (Sweden)

    Tatiana Olejníková

    2009-12-01

    Full Text Available Paper presents a family of helical two-revolutional cyclical surfaces, which arecreated by movement of the circle alongside the helical cycloidal curve, where circle islocated in the curve normal plane and its centre is on this curve. Helical cycloidal curvecan be created by simultaneous revolution of a point about two different axes 3o, 2o and byscrewing about axis 1o in the space. Form of the helical cycloidal curve and also of thehelical two-revolutional cyclical surface is dependent on the relative position of the threeaxes of revolutions, on multiples of angular velocities and orientations of separaterevolutions. Analytic representation, classification of surfaces and some of their geometricproperties are derived.

  12. The Hall Algebra of Cyclic Serial Algebra

    Institute of Scientific and Technical Information of China (English)

    郭晋云

    1994-01-01

    In this paper, orders <1 and <2 on ((Z)+)nm are introduced and also regarded as orders on the isomorphism classes of finite modules of finite .cyclic algebra R with n simple modules and all the indecomposable projective modules have length m through a one-to-one correspondence between ((Z)+)nm and the isomorphism classes of finite R modules. Using this we prove that the Hall algebra of a cyclic serial algebra is identified with its Loewy subalgebra, and its rational extension has a basis of BPW type, and is a (((Z)+)nm, <2) filtered ring with the associated graded ring as an iterated skew polynomial ring. These results are also generalized to the Hall algebra of a tube over a finite field.

  13. Bouncing and cyclic string gas cosmologies

    CERN Document Server

    Greene, Brian; Marnerides, Stefanos

    2008-01-01

    We show that, in the presence of a string gas, simple higher-derivative modifications to the effective action for gravity can lead to bouncing and cyclic cosmological models. The modifications bound the expansion rate and avoid singularities at finite times. In these models the scale factors can have long loitering phases that solve the horizon problem. Adding a potential for the dilaton gives a simple realization of the pre-big bang scenario. Entropy production in the cyclic phase drives an eventual transition to a radiation-dominated universe. As a test of the Brandenberger-Vafa scenario, we comment on the probability of decompactifying three spatial dimensions in this class of models.

  14. Cosmic Perturbations Through the Cyclic Ages

    CERN Document Server

    Erickson, J K; Steinhardt, P J; Turok, N G; Erickson, Joel K.; Gratton, Steven; Steinhardt, Paul J.; Turok, Neil

    2006-01-01

    We analyze the evolution of cosmological perturbations in the cyclic model, paying particular attention to their behavior and interplay over multiple cycles. Our key results are: (1) galaxies and large scale structure present in one cycle are generated by the quantum fluctuations in the preceding cycle without interference from perturbations or structure generated in earlier cycles and without interfering with structure generated in later cycles; (2) the ekpyrotic phase, an epoch of gentle contraction with equation of state $w\\gg 1$ preceding the hot big bang, makes the universe homogeneous, isotropic and flat within any given observer's horizon; and, (3) although the universe is uniform within each observer's horizon, the global structure of the cyclic universe is more complex, owing to the effects of superhorizon length perturbations, and cannot be described in a uniform Friedmann-Robertson-Walker picture. In particular, we show that the ekpyrotic phase is so effective in smoothing, flattening and isotropiz...

  15. Universal Cyclic Topology in Polymer Networks.

    Science.gov (United States)

    Wang, Rui; Alexander-Katz, Alfredo; Johnson, Jeremiah A; Olsen, Bradley D

    2016-05-01

    Polymer networks invariably possess topological defects: loops of different orders which have profound effects on network properties. Here, we demonstrate that all cyclic topologies are a universal function of a single dimensionless parameter characterizing the conditions for network formation. The theory is in excellent agreement with both experimental measurements of hydrogel loop fractions and Monte Carlo simulations without any fitting parameters. We demonstrate the superposition of the dilution effect and chain-length effect on loop formation. The one-to-one correspondence between the network topology and primary loop fraction demonstrates that the entire network topology is characterized by measurement of just primary loops, a single chain topological feature. Different cyclic defects cannot vary independently, in contrast to the intuition that the densities of all topological species are freely adjustable. Quantifying these defects facilitates studying the correlations between the topology and properties of polymer networks, providing a key step in overcoming an outstanding challenge in polymer physics.

  16. Detecting highly cyclic structure with complex eigenpairs

    CERN Document Server

    Klymko, Christine

    2016-01-01

    Many large, real-world complex networks have rich community structure that a network scientist seeks to understand. These communities may overlap or have intricate internal structure. Extracting communities with particular topological structure, even when they overlap with other communities, is a powerful capability that would provide novel avenues of focusing in on structure of interest. In this work we consider extracting highly-cyclic regions of directed graphs (digraphs). We demonstrate that embeddings derived from complex-valued eigenvectors associated with stochastic propagator eigenvalues near roots of unity are well-suited for this purpose. We prove several fundamental theoretic results demonstrating the connection between these eigenpairs and the presence of highly-cyclic structure and we demonstrate the use of these vectors on a few real-world examples.

  17. Generalized Toeplitz operators and cyclic vectors

    CERN Document Server

    Gassier, G; Zerouali, E H

    2003-01-01

    We give in this paper some asymptotic Von Neumann inequalities for power bounded operators in the class C subrho intersection C sub 1. and some spacial von Neumann inequalities associated with non zero elements of the point spectrum, when it is non void, of generalized Toeplitz operators. Introducing perturbed kernel, we consider classes C sub R which extend the classical classes C subrho. We give results about absolute continuity with respect to the Haar measure for operators in class C sub R intersection C sub 1. This allows us to give new results on cyclic vectors for such operators and provides invariant subspaces for their powers. Relationships between cyclic vectors for T and T* involving generalized Toeplitz operators are given and the commutativity of left brace T right brace', the commutant of T is discussed.

  18. Cyclic sieving, promotion, and representation theory

    CERN Document Server

    Rhoades, Brendon

    2010-01-01

    We prove a collection of conjectures of D. White \\cite{WComm}, as well as some related conjectures of Abuzzahab-Korson-Li-Meyer \\cite{AKLM} and of Reiner and White \\cite{ReinerComm}, \\cite{WComm}, regarding the cyclic sieving phenomenon of Reiner, Stanton, and White \\cite{RSWCSP} as it applies to jeu-de-taquin promotion on rectangular tableaux. To do this, we use Kazhdan-Lusztig theory and a characterization of the dual canonical basis of $\\mathbb{C}[x_{11}, ..., x_{nn}]$ due to Skandera \\cite{SkanNNDCB}. Afterwards, we extend our results to analyzing the fixed points of a dihedral action on rectangular tableaux generated by promotion and evacuation, suggesting a possible sieving phenomenon for dihedral groups. Finally, we give applications of this theory to cyclic sieving phenomena involving reduced words for the long elements of hyperoctohedral groups and noncrossing partitions.

  19. Cyclic and Quasi-Cyclic LDPC Codes on Row and Column Constrained Parity-Check Matrices and Their Trapping Sets

    CERN Document Server

    Huang, Qin; Lin, Shu; Abdel-Ghaffar, Khaled

    2010-01-01

    This paper is concerned with construction and structural analysis of both cyclic and quasi-cyclic codes, particularly LDPC codes. It consists of three parts. The first part shows that a cyclic code given by a parity-check matrix in circulant form can be decomposed into descendant cyclic and quasi-cyclic codes of various lengths and rates. Some fundamental structural properties of these descendant codes are developed, including the characterizations of the roots of the generator polynomial of a cyclic descendant code. The second part of the paper shows that cyclic and quasi-cyclic descendant LDPC codes can be derived from cyclic finite geometry LDPC codes using the results developed in first part of the paper. This enlarges the repertoire of cyclic LDPC codes. The third part of the paper analyzes the trapping sets of regular LDPC codes whose parity-check matrices satisfy a certain constraint on their rows and columns. Several classes of finite geometry and finite field cyclic and quasi-cyclic LDPC codes with l...

  20. Past Eras In Cyclic Cosmological Models

    CERN Document Server

    Frampton, Paul H

    2009-01-01

    In infinitely cyclic cosmology past eras are discussed using set theory and transfinite numbers. One consistent scenario, already in the literature, is where there is always a countably infinite number, $\\aleph_0$, of universes and no big bang. I describe here an alternative where the present number of universes is $\\aleph_0$ and in the infinite past there was only a finite number of universes. In this alternative model it is also possible that there was no big bang.

  1. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    J. L. Ballester

    2000-09-01

    Solar flares, prominences and CMEs are well known manifestations of solar activity. For many years, qualitative studies were made about the cyclical behaviour of such phenomena. Nowadays, more quantitative studies have been undertaken with the aim to understand the solar cycle dependence of such phenomena as well as peculiar behaviour, such as asymmetries and periodicities, occurring within the solar cycle. Here, we plan to review the more recent research concerning all these topics.

  2. Transversality for Cyclic Negative Feedback Systems

    OpenAIRE

    2014-01-01

    Transversality of stable and unstable manifolds of hyperbolic periodic trajectories is proved for monotone cyclic systems with negative feedback. Such systems in general are not in the category of monotone dynamical systems in the sense of Hirsch. Our main tool utilized in the proofs is the so-called cone of high rank. We further show that stable and unstable manifolds between a hyperbolic equilibrium and a hyperbolic periodic trajectory, or between two hyperbolic equilibria with different di...

  3. Breaking antidunes: Cyclic behavior due to hysteresis

    DEFF Research Database (Denmark)

    Deigaard, Rolf

    2006-01-01

    The cyclic behavior of breaking antidunes (growth, breaking of surface wave, obliteration) is investigated by use of a numerical model. The model includes the transition between supercritical and transcritical flow. As the antidune grows the flow becomes transcritical and a hydraulic jump is form...... upstream of the antidune crest. The relation between growth of the antidune and supercritical flow and between decay and transcritical flow is shown, and the significance of hysteresis in the flow conditions is investigated....

  4. Cyclic Strain Enhances Cellular Uptake of Nanoparticles

    OpenAIRE

    Jia Hu; Yaling Liu

    2015-01-01

    Nanoparticles (NPs) have gained increasing interest in recent years due to their potential use as drug carrier, imaging, and diagnostic agents in pharmaceutical and biomedical applications. While many cells in vivo experience mechanical forces, little is known about the correlation of the mechanical stimulation and the internalization of NPs into cells. This paper investigates the effects of applied cyclic strain on NP uptake by cells. Bovine aortic endothelial cells (BAECs) were cultured on ...

  5. Simple Current Actions of Cyclic Groups

    OpenAIRE

    Varga, Tamas

    2004-01-01

    Permutation actions of simple currents on the primaries of a Rational Conformal Field Theory are considered in the framework of admissible weighted permutation actions. The solution of admissibility conditions is presented for cyclic quadratic groups: an irreducible WPA corresponds to each subgroup of the quadratic group. As a consequence, the primaries of a RCFT with an order n integral or half-integral spin simple current may be arranged into multiplets of length k^2 (where k is a divisor o...

  6. Synthesis of a Cyclic Analogue of Galardin

    Institute of Scientific and Technical Information of China (English)

    马大为; 吴问根; 钱静; 郎深慧; 叶其壮

    2001-01-01

    A cyclic analogue 4 of galardin,a known MMP inhibitor,is designed to improve its selectivity.The synthesis of 4starts from dimethyl(S)-malate using diaselective alkylation and subsequent cyclization and amide formation as key steps.The compound 4 showed MMP inhibitory activity on all MMPs tested with IC50 ranging from 20.1 μM to 104 μM.

  7. General solution of the cyclic Leibniz rule

    Science.gov (United States)

    Kadoh, Daisuke; Ukita, Naoya

    2015-10-01

    We study the cyclic Leibniz rule (CLR) which was recently proposed as a new approach to the realization of supersymmetric quantum mechanics on the lattice. The CLR has an infinite number of solutions that give the different definitions of the lattice supersymmetric quantum mechanics. We show the general form of the solution for the naive symmetric difference operator and reveal the differences between the lattice models.

  8. Visualization of cyclic nucleotide dynamics in neurons

    Directory of Open Access Journals (Sweden)

    Kirill eGorshkov

    2014-12-01

    Full Text Available The second messengers cAMP and cGMP transduce many neuromodulatory signals from hormones and neurotransmitters into specific functional outputs. Their production, degradation and signaling are spatiotemporally regulated to achieve high specificity in signal transduction. The development of genetically encodable fluorescent biosensors has provided researchers with useful tools to study these versatile second messengers and their downstream effectors with unparalleled spatial and temporal resolution in cultured cells and living animals. In this review, we introduce the general design of these fluorescent biosensors and describe several of them in more detail. Then we discuss a few examples of using cyclic nucleotide fluorescent biosensors to study regulation of neuronal function and finish with a discussion of advances in the field. Although there has been significant progress made in understanding how the specific signaling of cyclic nucleotide second messengers is achieved, the mechanistic details in complex cell types like neurons are only just beginning to surface. Current and future fluorescent protein reporters will be essential to elucidate the role of cyclic nucleotide signaling dynamics in the functions of individual neurons and their networks.

  9. Cyclic dominance in evolutionary games: A review

    CERN Document Server

    Szolnoki, Attila; Jiang, Luo-Luo; Szczesny, Bartosz; Rucklidge, Alastair M; Perc, Matjaz

    2014-01-01

    Rock is wrapped by paper, paper is cut by scissors, and scissors are crushed by rock. This simple game is popular among children and adults to decide on trivial disputes that have no obvious winner, but cyclic dominance is also at the heart of predator-prey interactions, the mating strategy of side-blotched lizards, the overgrowth of marine sessile organisms, and the competition in microbial populations. Cyclical interactions also emerge spontaneously in evolutionary games entailing volunteering, reward, punishment, and in fact are common when the competing strategies are three or more regardless of the particularities of the game. Here we review recent advances on the rock-paper-scissors and related evolutionary games, focusing in particular on pattern formation, the impact of mobility, and the spontaneous emergence of cyclic dominance. We also review mean-field and zero-dimensional rock-paper-scissors models and the application of the complex Ginzburg-Landau equation, and we highlight the importance and use...

  10. Scale Factor Duality for Conformal Cyclic Cosmologies

    CERN Document Server

    dS, U Camara; Sotkov, G M

    2016-01-01

    The scale factor duality is a symmetry of dilaton gravity which is known to lead to pre-big-bang cosmologies. A conformal time version of the scale factor duality (SFD) was recently implemented as a UV/IR symmetry between decelerated and accelerated phases of the post-big-bang evolution within Einstein gravity coupled to a scalar field. The problem investigated in the present paper concerns the employment of the conformal time SFD methods to the construction of pre-big-bang and cyclic extensions of these models. We demonstrate that each big-bang model gives rise to two qualitatively different pre-big-bang evolutions: a contraction/expansion SFD model and Penrose's Conformal Cyclic Cosmology (CCC). A few examples of SFD symmetric cyclic universes involving certain gauged K\\"ahler sigma models minimally coupled to Einstein gravity are studied. We also describe the specific SFD features of the thermodynamics and the conditions for validity of the generalized second law in the case of Gauss-Bonnet (GB) extension ...

  11. Scale factor duality for conformal cyclic cosmologies

    Science.gov (United States)

    Camara da Silva, U.; Alves Lima, A. L.; Sotkov, G. M.

    2016-11-01

    The scale factor duality is a symmetry of dilaton gravity which is known to lead to pre-big-bang cosmologies. A conformal time version of the scale factor duality (SFD) was recently implemented as a UV/IR symmetry between decelerated and accelerated phases of the post-big-bang evolution within Einstein gravity coupled to a scalar field. The problem investigated in the present paper concerns the employment of the conformal time SFD methods to the construction of pre-big-bang and cyclic extensions of these models. We demonstrate that each big-bang model gives rise to two qualitatively different pre-big-bang evolutions: a contraction/expansion SFD model and Penrose's Conformal Cyclic Cosmology (CCC). A few examples of SFD symmetric cyclic universes involving certain gauged Kähler sigma models minimally coupled to Einstein gravity are studied. We also describe the specific SFD features of the thermodynamics and the conditions for validity of the generalized second law in the case of Gauss-Bonnet (GB) extension of these selected CCC models.

  12. Cyclical period changes in Z Chamaeleontis

    CERN Document Server

    Baptista, R; Oliveira, E; Vrielmann, S; Woudt, P A; Catalan, M S

    2002-01-01

    We report the identification of cyclical changes in the orbital period of the eclipsing dwarf nova Z Cha. We used times of mid-eclipse collected from the literature and our new eclipse timings to construct an observed-minus-calculated diagram covering 30 years of observations (1972-2002). The data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 28+/-2 yr and amplitude 1.0+/-0.2 minute. The statistical significance of this period by an F-test is larger than 99.9%. The derived fractional period change, Delta P/P= 4.4 x 10^{-7}, is comparable to that of other short-period cataclysmic variables (CVs), but is one order of magnitude smaller than those of the long-period CVs. Separate fits to the first and second half of the data lead to ephemerides with quite different cycle periods and amplitudes, indicating that the variation is not sinusoidal or, most probably, is not strictly periodic. The observed cyclical period change is possibly caused by a solar-type magnetic...

  13. Cosmology and Cosmogony in a Cyclic Universe

    Indian Academy of Sciences (India)

    Jayant V. Narlikar; Geoffrey Burbidge; R. G. Vishwakarma

    2007-06-01

    In this paper we discuss the properties of the quasi-steady state cosmological model (QSSC) developed in 1993 in its role as a cyclic model of the universe driven by a negative energy scalar field. We discuss the origin of such a scalar field in the primary creation process first described by F. Hoyle & J. V. Narlikar forty years ago. It is shown that the creation processes which take place in the nuclei of galaxies are closely linked to the high energy and explosive phenomena, which are commonly observed in galaxies at all redshifts. The cyclic nature of the universe provides a natural link between the places of origin of the microwave background radiation (arising in hydrogen burning in stars), and the origin of the lightest nuclei (H, D, He3 and He4). It also allows us to relate the large scale cyclic properties of the universe to events taking place in the nuclei of galaxies. Observational evidence shows that ejection of matter and energy from these centers in the form of compact objects, gas and relativistic particles is responsible for the population of quasi-stellar objects (QSOs) and gamma-ray burst sources in the universe. In the later parts of the paper we briefly discuss the major unsolved problems of this integrated cosmological and cosmogonical scheme – the understanding of the origin of the intrinsic redshifts, and the periodicities in the redshift distribution of the QSOs.

  14. Scale factor duality for conformal cyclic cosmologies

    Energy Technology Data Exchange (ETDEWEB)

    Silva, University Camara da; Lima, A.L. Alves; Sotkov, G.M. [Departamento de Física - CCE,Universidade Federal de Espirito Santo, 29075-900, Vitoria ES (Brazil)

    2016-11-16

    The scale factor duality is a symmetry of dilaton gravity which is known to lead to pre-big-bang cosmologies. A conformal time version of the scale factor duality (SFD) was recently implemented as a UV/IR symmetry between decelerated and accelerated phases of the post-big-bang evolution within Einstein gravity coupled to a scalar field. The problem investigated in the present paper concerns the employment of the conformal time SFD methods to the construction of pre-big-bang and cyclic extensions of these models. We demonstrate that each big-bang model gives rise to two qualitatively different pre-big-bang evolutions: a contraction/expansion SFD model and Penrose’s Conformal Cyclic Cosmology (CCC). A few examples of SFD symmetric cyclic universes involving certain gauged Kähler sigma models minimally coupled to Einstein gravity are studied. We also describe the specific SFD features of the thermodynamics and the conditions for validity of the generalized second law in the case of Gauss-Bonnet (GB) extension of these selected CCC models.

  15. Fractional Fourier domain analysis of cyclic multirate signal processing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The cyclic filter banks, which are used widely in the image subband coding, refer to signal processing on the finite field. This study investigates the fractional Fourier domain (FRFD) analysis of cyclic multirate systems based on the fractional circular convolution and chirp period. The proposed theorems include the fractional Fourier domain analysis of cyclic decimation and cyclic interpolation, the noble identities of cyclic decimation and cyclic interpolation in the FRFD, the polyphase represen-tation of cyclic signal in the FRFD, and the perfect reconstruction condition for the cyclic filter banks in the FRFD. Furthermore, this paper proposes the design methods for perfect reconstruction cyclic filter bank and cyclic filter bank with chirp modulation in the FRFD. The proposed theorems extend the multirate signal processing in the FRFD, which also advance the applications of the theorems of filter bank in the FRFD on the finite signal field, such as digital image processing. At last, the proposed design methods for the cyclic filter banks in the FRFD are validated by simulations.

  16. Multiaxial elastoplastic cyclic loading of austenitic 316L steel

    Directory of Open Access Journals (Sweden)

    V. Mazánová

    2017-04-01

    Full Text Available Cyclic stress-strain response and fatigue damage character has been investigated in austenitic stainless steel 316L. Hollow cylindrical specimens have been cyclically deformed in combined tension-compression and torsion under constant strain rate condition and different constant strain and shear strain amplitudes. In-phase and 90° out-of-phase cyclic straining was applied and the stress response has been monitored. Cyclic hardening/softening curves were assessed in both channels. Cyclic softening followed for higher strain amplitudes by long-term cyclic hardening was observed. Cyclic stress-strain curves were determined. Study of the surface damage in fractured specimens revealed the types and directions of principal cracks and the sources of fatigue crack initiation in slip bands.

  17. Hydroalcoholic Extract from Inflorescences of Achyrocline satureioides (Compositae) Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice by Attenuation in the Production of Inflammatory Cytokines and Oxidative Mediators

    Science.gov (United States)

    da Silva, Luisa Mota; Farias, Jaime Antonio Machado; Boeing, Thaise; Somensi, Lincon Bordignon; Beber, Ana Paula; Cury, Benhur Judah

    2016-01-01

    Achyrocline satureioides is a South American herb used to treat inflammatory and gastrointestinal diseases. This study evaluated intestinal anti-inflammatory effects of the hydroalcoholic extract of inflorescences of satureioides (HEAS) in dextran sulfate sodium (DSS) induced colitis in mice. Mice were orally treated with vehicle, 5-aminosalicylic acid (100 mg/kg), or HEAS (1–100 mg/kg). Clinical signs of colitis and colonic histopathological parameters were evaluated, along with the determination of levels of reduced glutathione and lipid hydroperoxide (LOOH), the superoxide dismutase (SOD), and myeloperoxidase (MPO) activity in colon. The colonic content of cytokines (TNF, IL-4, IL-6, and IL-10) was measured. Additionally, the effects of the extract on nitric oxide (NO) release by lipopolysaccharide (LPS) stimulated macrophages and diphenylpicrylhydrazyl levels were determined. Mucin levels and SOD activity, as well as the LOOH, MPO, TNF, and IL-6 accumulation in colon tissues, were normalized by the HEAS administration. In addition, the extract elicited an increase in IL-4 and IL-10 levels in colon. NO release by macrophages was inhibited by HEAS and its scavenger activity was confirmed. Together these results suggest that preparations obtained from inflorescences from A. satureioides could be used in treatment for IBD. Besides, this work corroborates the popular use of A. satureioides in inflammatory disorders. PMID:27847525

  18. Hydroalcoholic Extract from Inflorescences of Achyrocline satureioides (Compositae Ameliorates Dextran Sulphate Sodium-Induced Colitis in Mice by Attenuation in the Production of Inflammatory Cytokines and Oxidative Mediators

    Directory of Open Access Journals (Sweden)

    Luisa Mota da Silva

    2016-01-01

    Full Text Available Achyrocline satureioides is a South American herb used to treat inflammatory and gastrointestinal diseases. This study evaluated intestinal anti-inflammatory effects of the hydroalcoholic extract of inflorescences of satureioides (HEAS in dextran sulfate sodium (DSS induced colitis in mice. Mice were orally treated with vehicle, 5-aminosalicylic acid (100 mg/kg, or HEAS (1–100 mg/kg. Clinical signs of colitis and colonic histopathological parameters were evaluated, along with the determination of levels of reduced glutathione and lipid hydroperoxide (LOOH, the superoxide dismutase (SOD, and myeloperoxidase (MPO activity in colon. The colonic content of cytokines (TNF, IL-4, IL-6, and IL-10 was measured. Additionally, the effects of the extract on nitric oxide (NO release by lipopolysaccharide (LPS stimulated macrophages and diphenylpicrylhydrazyl levels were determined. Mucin levels and SOD activity, as well as the LOOH, MPO, TNF, and IL-6 accumulation in colon tissues, were normalized by the HEAS administration. In addition, the extract elicited an increase in IL-4 and IL-10 levels in colon. NO release by macrophages was inhibited by HEAS and its scavenger activity was confirmed. Together these results suggest that preparations obtained from inflorescences from A. satureioides could be used in treatment for IBD. Besides, this work corroborates the popular use of A. satureioides in inflammatory disorders.

  19. A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

    Directory of Open Access Journals (Sweden)

    Nevzat Selim Gokay

    2016-01-01

    Full Text Available The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg, inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg, or nitric oxide precursor L-arginine (200 mg/kg. After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P=0.044 positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders.

  20. Nitric oxide in liver inflammation and regeneration.

    Science.gov (United States)

    Martin-Sanz, Paloma; Hortelano, Sonsoles; Callejas, Nuria A; Goren, Nora; Casado, Marta; Zeini, Miriam; Boscá, Lisardo

    2002-12-01

    Hepatocytes express and release inflammatory mediators after challenge with bacterial cell wall molecules and proinflammatory cytokines. Nitric oxide synthase-2 (NOS-2) is expressed under these conditions and the high-output NO synthesis that follows contributes to the inflammatory response in this tissue and participates in the onset of several hepatopathies. However, in the course of liver regeneration, for example, after partial hepatectomy, NOS-2 is expressed at moderate levels and contributes to inhibit apoptosis and to favor progression in the cell cycle until the organ size and function are restored. The mechanisms involved in the regulation of NOS-2 expression under these conditions are revised.

  1. Nitric oxide and plant iron homeostasis.

    Science.gov (United States)

    Buet, Agustina; Simontacchi, Marcela

    2015-03-01

    Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes.

  2. Nitric oxide synthase inhibition and cerebrovascular regulation

    DEFF Research Database (Denmark)

    Iadecola, C; Pelligrino, D A; Moskowitz, M A;

    1994-01-01

    tone and may play an important role in selected vasodilator responses of the cerebral circulation. Furthermore, evidence has been presented suggesting that NO participates in the mechanisms of cerebral ischemic damage. Despite the widespread attention that NO has captured in recent years and the large......There is increasing evidence that nitric oxide (NO) is an important molecular messenger involved in a wide variety of biological processes. Recent data suggest that NO is also involved in the regulation of the cerebral circulation. Thus, NO participants in the maintenance of resting cerebrovascular...

  3. EFFECTS OF NITRIC ACID ON CRITICALITY SAFETY ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, B.

    2011-08-18

    As nitric acid molarity is increased, there are two competing phenomena affecting the reactivity of the system. First, there is interaction between each of the 10 wells in the basket-like insert. As the molarity of the nitric acid solution is increased (it moves from 100% water to 100% HNO{sub 3}), the hydrogen atom density decreases by about 80%. However, it remains a relatively efficient moderator. The moderating ratio of nitric acid is about 90% that of water. As the media between the wells is changed from 100% water to 100% nitric acid, the density of the media increases by 50%. A higher density typically leads to a better reflector. However, when the macroscopic scattering cross sections are considered, nitric acid is a much worse reflector than water. The effectiveness of nitric acid as a reflector is about 40% that of water. Since the media between the wells become a worse reflector and still remains an effective moderator, interaction between the wells increases. This phenomenon will cause reactivity to increase as nitric acid molarity increases. The seond phenomenon is due to the moderating ratio changing in the high concentration fissile-nitric acid solution in the 10 wells. Since the wells contain relatively small volumes of high concentration solutions, a small decrease in moderating power has a large effect on reactivity. This is due to the fact that neutrons are more likely to escape the high concentration fissile solution before causing another fission event. The result of this phenomenon is that as nitric acid molarity increases, reactivity decreases. Recent studies have shown that the second phenomenon is indeed the dominating force in determining reactivity changes in relation to nitric acid molarity changes. When considering the system as a whole, as nitric acid molarity increases, reactivity decreases.

  4. Efficient Synthesis of Cyclic Block Copolymers by Rotaxane Protocol by Linear/Cyclic Topology Transformation.

    Science.gov (United States)

    Valentina, Stephanie; Ogawa, Takahiro; Nakazono, Kazuko; Aoki, Daisuke; Takata, Toshikazu

    2016-06-20

    High-yielding synthesis of cyclic block copolymer (CBC) using the rotaxane protocol by linear-cyclic polymer topology transformation was first demonstrated. Initial complexation of OH-terminated sec-ammonium salt and a crown ether was followed by the successive living ring-opening polymerizations of two lactones to a linear block copolymer having a rotaxane structure by the final capping of the propagation end. CBC was obtained in a high yield by an exploitation of the mechanical linkage through the translational movement of the rotaxane component to transform polymer structure from linear to cyclic. Furthermore, the change of the polymer topology was translated into a macroscopic change in crystallinity of the block copolymer.

  5. Statistical damage constitutive model for rocks subjected to cyclic stress and cyclic temperature

    Science.gov (United States)

    Zhou, Shu-Wei; Xia, Cai-Chu; Zhao, Hai-Bin; Mei, Song-Hua; Zhou, Yu

    2017-08-01

    A constitutive model of rocks subjected to cyclic stress-temperature was proposed. Based on statistical damage theory, the damage constitutive model with Weibull distribution was extended. Influence of model parameters on the stress-strain curve for rock reloading after stress-temperature cycling was then discussed. The proposed model was initially validated by rock tests for cyclic stress-temperature and only cyclic stress. Finally, the total damage evolution induced by stress-temperature cycling and reloading after cycling was explored and discussed. The proposed constitutive model is reasonable and applicable, describing well the stress-strain relationship during stress-temperature cycles and providing a good fit to the test results. Elastic modulus in the reference state and the damage induced by cycling affect the shape of reloading stress-strain curve. Total damage induced by cycling and reloading after cycling exhibits three stages: initial slow increase, mid-term accelerated increase, and final slow increase.

  6. Cyclic GMP protects human macrophages against peroxynitrite-induced apoptosis

    Directory of Open Access Journals (Sweden)

    Rossi Adriano G

    2009-05-01

    Full Text Available Abstract Background Nitric oxide (NO can be both pro- and anti-apoptotic in various cell types, including macrophages. This apparent paradox may result from the actions of NO-related species generated in the microenvironment of the cell, for example the formation of peroxynitrite (ONOO-. In this study we have examined the ability of NO and ONOO- to evoke apoptosis in human monocyte-derived macrophages (MDMϕ, and investigated whether preconditioning by cyclic guanosine monophosphate (cGMP is able to limit apoptosis in this cell type. Methods Characterisation of the NO-related species generated by (Z-1- [2-(2-aminoethyl-N-(2-ammonioethylamino]diazen-1-ium-1,2-diolate (DETA/NO and 1,2,3,4-oxatriazolium, 5-amino-3-(3,4-dichlorophenyl-, chloride (GEA-3162 was performed by electrochemistry using an isolated NO electrode and electron paramagnetic resonance (EPR spectrometry. Mononuclear cells were isolated from peripheral blood of healthy volunteers and cultured to allow differentiation into MDMϕ. Resultant MDMϕ were treated for 24 h with DETA/NO (100 – 1000 μM or GEA-3162 (10 – 300 μM in the presence or absence of BAY 41–2272 (1 μM, isobutylmethylxanthine (IBMX; 1 μM, 1H- [1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ; 20 μM or 8-bromo-cGMP (1 mM. Apoptosis in MDMϕ was assessed by flow cytometric analysis of annexin V binding in combination with propidium iodide staining. Results Electrochemistry and EPR revealed that DETA/NO liberated free NO radical, whilst GEA-3162 concomitantly released NO and O2-, and is therefore a ONOO- generator. NO (DETA/NO had no effect on cell viability, but ONOO- (GEA-3162 caused a concentration-dependent induction of apoptosis in MDMϕ. Preconditioning of MDMϕ with NO in combination with the phosphodiesterase inhibitor, 3-Isobutyl-1-methylxanthine (IBMX, or the NO-independent stimulator of soluble guanylate cyclase, BAY 41–2272, significantly attenuated ONOO--induced apoptosis in a cGMP-dependent manner

  7. Involvement of nitric oxide pathways in short term modulation of tyrosine hydroxylase activity by endothelins 1 and 3 in the rat anterior hypothalamus.

    Science.gov (United States)

    Morgazo, Carolina; Perfume, Guadalupe; Legaz, Guillermina; di Nunzio, Andrea; Hope, Sandra I; Bianciotti, Liliana G; Vatta, Marcelo S

    2005-09-02

    The ability of endothelins 1 and 3 (ET-1 and ET-3) to reduce neuronal norepinephrine release through ETB receptor activation involving nitric oxide (NO) pathways in the rat anterior hypothalamus region (AHR) was previously reported. In the present work, we studied the effects of ET-1 and -3 on tyrosine hydroxylase (TH) activity and the possible involvement of NO pathways. Results showed that ET-1 and -3 (10 nM) diminished TH activity in AHR and this effect was blocked by a selective ETB receptor antagonist (100 nM BQ-788), but not by a ET(A) receptor antagonist (BQ-610). To confirm these results, 1 microM IRL-1620 (ET(B) agonist) reduced TH activity whereas 300 nM sarafotoxin S6b falled to modify it. N(omega)-Nitro-L-arginine methyl ester (10 microM), 7-nitroindazole (10 microM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-ona (10 microM), KT5823 (2 microM), inhibitors of nitric oxide synthase, neuronal nitric oxide synthase, NO-sensitive-guanylyl cyclase, and protein kinase G, respectively, did not modify the reduction of TH activity produced by ETs. In addition, both 100 microM sodium nitroprusside and 50 microM 8-bromoguanosine-3',5'-cyclic monophosphate (NO donor and guanosine-3',5'-cyclic monophosphate analog, respectively) diminished TH activity. Present results showed that ET-1 and ET-3 diminished TH activity through the activation of ET(B) receptors involving the NO/guanosine-3',5'-cyclic monophosphate/protein kinase G pathway. Taken jointly present and previous results it can be concluded that both ETs play an important role as modulators of norepinephrine neurotransmission in the rat AHR.

  8. Cyclic AMP and cyclic GMP levels in glandular stomach of restrained rats.

    Science.gov (United States)

    Zarrindast, M R; Sharghi, G; Gerayesh-Nejad, S; Djahanguiri, B

    1977-10-01

    Cyclic AMP and cyclic GMP were measured in glandular stomach of rats subjected to saline administration, cold (4 degrees C), restraint and restraint+cold after 15, 30, 60, 90 and 120 minutes. All animals subjected to restraint+cold had gastric ulceration after 2 hours. A significant but transient decrease in cAMP was observed 15 minutes after restraint+cold. A marked, sustained and significant decrease of cGMP was observed in the same group of animals. It is concluded that it seems unlikely to be a correlation between cAMP and cGMP changes of the stomach and the restraint-induced gastric ulceration.

  9. Adrenoceptor-activated nitric oxide synthesis in salivary acinar cells

    DEFF Research Database (Denmark)

    Looms, Dagnia; Dissing, Steen; Tritsaris, Katerina

    2000-01-01

    We investigated the cellular regulation of nitric oxide synthase (NOS) activity in isolated acinar cells from rat parotid and human labial salivary glands, using the newly developed fluorescent nitric oxide (NO) indicator, DAF-2. We found that sympathetic stimulation with norepinephrine (NE) caus...

  10. Catalytic abatement of nitrous oxide from nitric and production

    NARCIS (Netherlands)

    Oonk, J.

    1998-01-01

    Nitric acid production is identified as a main source of nitrous oxide. Options for emission reduction however are not available. TNO and Hydro Agri studied the technological and economic feasibility of catalytic decomposition of nitrous oxide in nitric acid tail-gases. Although in literature promis

  11. The role of nitric oxide in cancer

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including va-sodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases(NOS) comprises inducible NOS (iNOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Interest-ingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting theetiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and hasbeen associated with tumour grade, proliferation rate and expression of important signaling componentsassociated with cancer development such as the oestrogen receptor. It appears that high levels of NOSexpression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumorcells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxicallytherefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic properties.Increased NO-generation in a cell may select mutant p53 cells and contribute to tumour angiogenesis byupregulating VEGF. In addition, NO may modulate tumour DNA repair mechanisms by upregulating p53,poly(ADP-ribose) polymerase (PARP) and the DNA-dependent protein kinase (DNA-PK). An understand-ing at the molecular level of the role of NO in cancer will have profound therapeutic implications for thediagnosis and treatment of disease.

  12. Metastable Nitric Acid Trihydrate in Ice Clouds

    Science.gov (United States)

    Weiss, Fabian; Kubel, Frank; Gálvez, Oscar; Hölzel, Markus; Parker, Stewart F.; Baloh, Philipp; Iannarelli, Riccardo; Rossi, Michel J.; Grothe, Hinrich

    2016-04-01

    The composition of high altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates. The identification and formation mechanisms, however, are still unknown but are essential to understand atmospheric processing such as the seasonal ozone depletion in the lower polar stratosphere or the radiation balance of planet Earth. We found conclusive evidence for a long-predicted phase, which has been named alpha nitric acid trihydrate (alpha-NAT). This phase has been proven by combination of X-ray and neutron diffraction experiments allowing a convincing structure solution. Additionally, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong affinity between water ice and alpha-NAT has been found, which explains the experimental spectra and the phase transition kinetics essential for identification in the atmosphere. On the basis of our results, we propose a new three-step mechanism for NAT-formation in high altitude ice clouds. F. Weiss et al. Angew. Chem. Int. Ed. 2016, accepted, DOI:10.1002/anie.201510841

  13. Expired nitric oxide levels in adult asthmatics

    Directory of Open Access Journals (Sweden)

    Chiharu Okada

    1996-01-01

    Full Text Available The expired nitric oxide (NO concentration is known to be higher in asthmatic subjects than in normal subjects. To elucidate the role of NO in asthma, we examined the expired NO concentrations in relation to the type (atopic, mixed, non- atopic, and severity (mild, moderate, severe of asthmatics, as well as the influence of steroid treatment. Twenty-seven normal subjects, 48 asthmatics, 8 subjects with allergic rhinitis, and 13 subjects with pulmonary emphysema participated in the study. The expired NO concentration was significantly higher in asthmatics and patients with allergic rhinitis than in normal subjects (P<0.01. No significant difference was observed between the expired NO concentration in patients with pulmonary emphysema and that of normal subjects. The expired NO concentrations were significantly lower in non- atopic asthma than in atopic asthma. Nitric oxide levels were significantly lower in severe asthma than in mild asthma. High doses of steroid treatment are often used in severe asthma. The dose of inhaled beclomethasone and expired NO concentrations showed a negative correlation (r= −0.51587, P<0.004. Drip infusion of hydrocortisone tended to increase the exhaled NO concentration just after drip infusion, however, it decreased after 24 h. These results suggest that steroid treatment decreases the expired NO concentrations in asthmatics, although it cannot be concluded that NO increases the severity of asthma. The measurement of expired NO concentrations is an easy, non-invasive test, which may be a useful tool for monitoring the condition of asthmatics.

  14. Isolation of a Cyclic (Alkyl(aminogermylene

    Directory of Open Access Journals (Sweden)

    Liliang Wang

    2016-07-01

    Full Text Available A 1,4-addition of a dichlorogermylene dioxane complex with α,β-unsaturated imine 1 gave a dichlorogermane derivative 2 bearing a GeC3N five-membered ring skeleton. By reducing 2 with KC8, cyclic (alkyl(aminogermylene 3 was synthesized and fully characterized. Germylene 3 readily reacted with TEMPO, N2O and S8, producing the 1:2 adduct 4, the oxo-bridged dimer 5 and the sulfido-bridged dimer 6, respectively.

  15. Periodic cyclic homology of affine Hecke algebras

    CERN Document Server

    Solleveld, Maarten

    2009-01-01

    This is the author's PhD-thesis, which was written in 2006. The version posted here is identical to the printed one. Instead of an abstract, the short list of contents: Preface 5 1 Introduction 9 2 K-theory and cyclic type homology theories 13 3 Affine Hecke algebras 61 4 Reductive p-adic groups 103 5 Parameter deformations in affine Hecke algebras 129 6 Examples and calculations 169 A Crossed products 223 Bibliography 227 Index 237 Samenvatting 245 Curriculum vitae 253

  16. Cyclic groups and quantum logic gates

    Science.gov (United States)

    Pourkia, Arash; Batle, J.; Raymond Ooi, C. H.

    2016-10-01

    We present a formula for an infinite number of universal quantum logic gates, which are 4 by 4 unitary solutions to the Yang-Baxter (Y-B) equation. We obtain this family from a certain representation of the cyclic group of order n. We then show that this discrete family, parametrized by integers n, is in fact, a small sub-class of a larger continuous family, parametrized by real numbers θ, of universal quantum gates. We discuss the corresponding Yang-Baxterization and related symmetries in the concomitant Hamiltonian.

  17. Simple Current Actions of Cyclic Groups

    CERN Document Server

    Varga, T

    2004-01-01

    Permutation actions of simple currents on the primaries of a Rational Conformal Field Theory are considered in the framework of admissible weighted permutation actions. The solution of admissibility conditions is presented for cyclic quadratic groups: an irreducible WPA corresponds to each subgroup of the quadratic group. As a consequence, the primaries of a RCFT with an order n integral or half-integral spin simple current may be arranged into multiplets of length k^2 (where k is a divisor of n) or 3k^2 if the spin of the simple current is half-integral and k is odd.

  18. A cyclic universe approach to fine tuning

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Stephon, E-mail: stephon.alexander@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Department of Physics, Brown University, Providence, RI 02906 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Gleiser, Marcelo, E-mail: marcelo.gleiser@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2016-06-10

    We present a closed bouncing universe model where the value of coupling constants is set by the dynamics of a ghost-like dilatonic scalar field. We show that adding a periodic potential for the scalar field leads to a cyclic Friedmann universe where the values of the couplings vary randomly from one cycle to the next. While the shuffling of values for the couplings happens during the bounce, within each cycle their time-dependence remains safely within present observational bounds for physically-motivated values of the model parameters. Our model presents an alternative to solutions of the fine tuning problem based on string landscape scenarios.

  19. Neuronal nitric oxide synthase-rescue of dystrophin/utrophin double knockout mice does not require nNOS localization to the cell membrane.

    Directory of Open Access Journals (Sweden)

    Michelle Wehling-Henricks

    Full Text Available Survival of dystrophin/utrophin double-knockout (dko mice was increased by muscle-specific expression of a neuronal nitric oxide synthase (nNOS transgene. Dko mice expressing the transgene (nNOS TG+/dko experienced delayed onset of mortality and increased life-span. The nNOS TG+/dko mice demonstrated a significant decrease in the concentration of CD163+, M2c macrophages that can express arginase and promote fibrosis. The decrease in M2c macrophages was associated with a significant reduction in fibrosis of heart, diaphragm and hindlimb muscles of nNOS TG+/dko mice. The nNOS transgene had no effect on the concentration of cytolytic, CD68+, M1 macrophages. Accordingly, we did not observe any change in the extent of muscle fiber lysis in the nNOS TG+/dko mice. These findings show that nNOS/NO (nitric oxide-mediated decreases in M2c macrophages lead to a reduction in the muscle fibrosis that is associated with increased mortality in mice lacking dystrophin and utrophin. Interestingly, the dramatic and beneficial effects of the nNOS transgene were not attributable to localization of nNOS protein at the cell membrane. We did not detect any nNOS protein at the sarcolemma in nNOS TG+/dko muscles. This important observation shows that sarcolemmal localization is not necessary for nNOS to have beneficial effects in dystrophic tissue and the presence of nNOS in the cytosol of dystrophic muscle fibers can ameliorate the pathology and most importantly, significantly increase life-span.

  20. Direct measurements of nitric oxide release in relation to expression of endothelial nitric oxide synthase in isolated porcine mitral valves

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Olsen, Lisbeth Høier; Aasted, Bent;

    2007-01-01

    The aim of this study was to measure the direct release of nitric oxide (NO) from the porcine mitral valve using a NO microelectrode. Furthermore, the expression and localization of endothelial nitric oxide synthase (eNOS) in the mitral valve was studied using immunohistochemistry, Western blotting...

  1. CyclicCO2R: production of cyclic carbonates from CO2 using renewable feedstocks

    NARCIS (Netherlands)

    Kimball, E.; Schuurbiers, C.A.H.; Zevenbergen, J.F.; Håkonsen, S.F.; Heyn, R.; Offermans, W.; Leitner, W.; Ostapowicz, T.; Müller, T. E.; Mul, G.; North, M.; Ngomsik-Fanselow, A.F.; Sarron, E.; Sigurbjörnsson, O.; Schäffner, B.

    2013-01-01

    The consortium behind CyclicCO2R wants to kick-start the implementation of CO2 utilization technologies by converting CO2 into a high value-added product, thus providing a showcase that inspires industry to further develop technologies utilizing CO2 as a sustainable raw material and valorizing CO2

  2. CyclicCO2R: production of cyclic carbonates from CO2 using renewable feedstocks

    NARCIS (Netherlands)

    Kimball, E.; Schuurbiers, C.A.H.; Zevenbergen, J.F.; Håkonsen, S.F.; Heyn, R.; Offermans, W.; Leitner, W.; Ostapowicz, T.; Müller, T. E.; Mul, G.; North, M.; Ngomsik-Fanselow, A.F.; Sarron, E.; Sigurbjörnsson, O.; Schäffner, B.

    2013-01-01

    The consortium behind CyclicCO2R wants to kick-start the implementation of CO2 utilization technologies by converting CO2 into a high value-added product, thus providing a showcase that inspires industry to further develop technologies utilizing CO2 as a sustainable raw material and valorizing CO2 i

  3. Cyclical components of local rainfall data

    Science.gov (United States)

    Mentz, R. P.; D'Urso, M. A.; Jarma, N. M.; Mentz, G. B.

    2000-02-01

    This paper reports on the use of a comparatively simple statistical methodology to study local short time series rainfall data. The objective is to help in agricultural planning, by diminishing the risks associated with some uncertainties affecting this business activity.The analysis starts by assuming a model of unobservable components, trend, cycle, seasonal and irregular, that is well known in many areas of application. When series are in the realm of business and economics, the statistical methods popularized by the US Census Bureau US National Bureau of Economic Research are used for seasonal and cyclical estimation, respectively. The flexibility of these methods makes them good candidates to be applied in the meteorological context, and this is done in this paper for a selection of monthly rainfall time series.Use of the results to help in analysing and forecasting cyclical components is emphasized. The results are interesting. An agricultural entrepreneur, or a group of them located in a single geographical region, will profit by systematically collecting information (monthly in our work) about rainfall, and adopting the scheme of analysis described in this paper.

  4. Evolution of cyclic peptide protease inhibitors.

    Science.gov (United States)

    Young, Travis S; Young, Douglas D; Ahmad, Insha; Louis, John M; Benkovic, Stephen J; Schultz, Peter G

    2011-07-05

    We report a bacterial system for the evolution of cyclic peptides that makes use of an expanded set of amino acid building blocks. Orthogonal aminoacyl-tRNA synthetase/tRNA(CUA) pairs, together with a split intein system were used to biosynthesize a library of ribosomal peptides containing amino acids with unique structures and reactivities. This peptide library was subsequently used to evolve an inhibitor of HIV protease using a selection based on cellular viability. Two of three cyclic peptides isolated after two rounds of selection contained the keto amino acid p-benzoylphenylalanine (pBzF). The most potent peptide (G12: GIXVSL; X=pBzF) inhibited HIV protease through the formation of a covalent Schiff base adduct of the pBzF residue with the ε-amino group of Lys 14 on the protease. This result suggests that an expanded genetic code can confer an evolutionary advantage in response to selective pressure. Moreover, the combination of natural evolutionary processes with chemically biased building blocks provides another strategy for the generation of biologically active peptides using microbial systems.

  5. A cyclically actuated electrolytic drug delivery device

    KAUST Repository

    Yi, Ying

    2015-01-01

    This work, focusing on an implantable drug delivery system, presents the first prototype electrolytic pump that combines a catalytic reformer and a cyclically actuated mode. These features improve the release performance and extend the lifetime of the device. Using our platinum (Pt)-coated carbon fiber mesh that acts as a catalytic reforming element, the cyclical mode is improved because the faster recombination rate allows for a shorter cycling time for drug delivery. Another feature of our device is that it uses a solid-drug-in-reservoir (SDR) approach, which allows small amounts of a solid drug to be dissolved in human fluid, forming a reproducible drug solution for long-term therapies. We have conducted proof-of-principle drug delivery studies using such an electrolytic pump and solvent blue 38 as the drug substitute. These tests demonstrate power-controlled and pulsatile release profiles of the chemical substance, as well as the feasibility of this device. A drug delivery rate of 11.44 ± 0.56 μg min-1 was achieved by using an input power of 4 mW for multiple pulses, which indicates the stability of our system. © The Royal Society of Chemistry 2015.

  6. Cyclic integrals and reduction of rotational relativistic Birkhoffian system

    Institute of Scientific and Technical Information of China (English)

    罗绍凯

    2003-01-01

    The order reduction method of the rotational relativistic Birkhoffian equations is studied. For a rotational relativistic Birkhoffian system, the cyclic integrals can be found by using the perfect differential method. Through these cyclic integrals, the order of the system can be reduced. If the rotational relativistic Birkhoffian system has a cyclic integral, then the Birkhoffian equations can be reduced at least two degrees and the Birkhoffian form can be kept. An example is given to illustrate the application of the results.

  7. Cyclic Voltammetry of Polysulfide (Thiokol) Prepolymers and Related Compounds

    Science.gov (United States)

    1983-12-01

    low scan rates suqges t that A and B are unstable and undergo chesical reactions on the cyclic voltametry time scale. A more detailed examination is...REPOR CYCLIC VOLTAq4ETRY OF POLYSIILF!OE (THIOKOL) PREPOLYMERS AND~ RELATED COMPODWS Waldemar Nazurek ThE UPrEDT STATES NATIONAL. CZTECMNNCAL...DEPARTMENT OF DEFENCE MATERIALS RESEARCH LABORATORIES REPORT MRL-R.911 CYCLIC VOLTAP,4ETRY OF POLYSULFIDE (THIOKOL) PREPOLYMERS AND RELATEn COMPOUNDS 𔃻

  8. Cyclic cocycles on deformation quantizations and higher index theorems

    CERN Document Server

    Pflaum, M; Tang, X

    2008-01-01

    We construct a nontrivial cyclic cocycle on the Weyl algebra of a symplectic vector space. Using this cyclic cocycle we construct an explicit, local, quasi-isomorphism from the complex of differential forms on a symplectic manifold to the complex of cyclic cochains of any formal deformation quantization thereof. We prove an algebraic higher index theorem by computing the pairing between such cyclic cocycles and the $K$-theory of the formal deformation quantization. As an application, we obtain the analytic higher index theorem of Connes--Moscovici.

  9. Cyclic structures in algebraic (co)homology theories

    CERN Document Server

    Kowalzig, Niels

    2010-01-01

    This note discusses the cyclic cohomology of a left Hopf algebroid ($\\times_A$-Hopf algebra) with coefficients in a right module-left comodule, defined using a straightforward generalisation of the original operators given by Connes and Moscovici for Hopf algebras. Lie-Rinehart homology is a special case of this theory. A generalisation of cyclic duality that makes sense for arbitrary para-cyclic objects yields a dual homology theory. The twisted cyclic homology of an associative algebra provides an example of this dual theory that uses coefficients that are not necessarily stable anti Yetter-Drinfel'd modules.

  10. Production of Nitric Oxide and Expression of Inducible Nitric Oxide Synthase in Ovarian Cystic Tumors

    Directory of Open Access Journals (Sweden)

    Rosekeila Simões Nomelini

    2008-01-01

    Full Text Available Tumor sections from nonneoplastic (n=15, benign (n=28, and malignant ovarian tumors (n=20 were obtained from 63 women. Immunohistochemistry of the tumor sections demonstrated that inducible nitric oxide synthase (iNOS expression was increased in ovarian cancer samples compared to nonneoplastic or benign tumor samples. Using the Griess method, nitric oxide (NO metabolite levels were also found to be elevated in malignant tumor samples compared to benign tumor samples (P80 μM were more frequent than NO levels <80 μM, and iNOS expression in well-differentiated carcinomas was greater than in moderately/poorly differentiated carcinomas (P<.05. These data suggest an important role for NO in ovarian carcinogenesis.

  11. Nitric oxide-induced calcium release: activation of type 1 ryanodine receptor, a calcium release channel, through non-enzymatic posttranslational modification by nitric oxide

    Directory of Open Access Journals (Sweden)

    Sho eKakizawa

    2013-10-01

    Full Text Available Nitric oxide (NO is a typical gaseous messenger involved in a wide range of biological processes. In our classical knowledge, effects of NO are largely achieved by activation of soluble guanylyl cyclase to form cyclic guanosine-3’, 5’-monophosphate. However, emerging evidences have suggested another signaling mechanism mediated by NO: S-nitrosylation of target proteins.S-nitrosylation is a covalent addition of an NO group to a cysteine thiol/sulfhydryl (RSH, and categorized into non-enzymatic posttranslational modification of proteins, contrasted to enzymatic posttranslational modification of proteins, such as phosphorylation mediated by various protein kinases.Very recently, we found novel intracellular calcium (Ca2+ mobilizing mechanism, NO-induced Ca2+ release (NICR in cerebellar Purkinje cells. NICR is mediated by type 1 ryanodine receptor (RyR1, a Ca2+ release channel expressed in endoplasmic-reticular membrane. Furthermore, NICR is indicated to be dependent on S-nitrosylation of RyR1, and involved in synaptic plasticity in the cerebellum. In this review, molecular mechanisms and functional significance of NICR, as well as non-enzymatic posttranslational modification of proteins by gaseous signals, are described.

  12. Nitric oxide in liver fibrosis: The role of inducible nitric oxide synthase.

    Science.gov (United States)

    Iwakiri, Yasuko

    2015-12-01

    The inducible form of nitric oxide synthase (iNOS) is expressed in hepatic cells in pathological conditions. Its induction is involved in the development of liver fibrosis, and thus iNOS could be a therapeutic target for liver fibrosis. This review summarizes the role of iNOS in liver fibrosis, focusing on 1) iNOS biology, 2) iNOS-expressing liver cells, 3) iNOS-related therapeutic strategies, and 4) future directions.

  13. Hypoxia tolerance, nitric oxide, and nitrite

    DEFF Research Database (Denmark)

    Fago, Angela; Jensen, Frank Bo

    2015-01-01

    Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia...... survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance...

  14. Nitric oxide-releasing porous silicon nanoparticles

    Science.gov (United States)

    Kafshgari, Morteza Hasanzadeh; Cavallaro, Alex; Delalat, Bahman; Harding, Frances J.; McInnes, Steven JP; Mäkilä, Ermei; Salonen, Jarno; Vasilev, Krasimir; Voelcker, Nicolas H.

    2014-07-01

    In this study, the ability of porous silicon nanoparticles (PSi NPs) to entrap and deliver nitric oxide (NO) as an effective antibacterial agent is tested against different Gram-positive and Gram-negative bacteria. NO was entrapped inside PSi NPs functionalized by means of the thermal hydrocarbonization (THC) process. Subsequent reduction of nitrite in the presence of d-glucose led to the production of large NO payloads without reducing the biocompatibility of the PSi NPs with mammalian cells. The resulting PSi NPs demonstrated sustained release of NO and showed remarkable antibacterial efficiency and anti-biofilm-forming properties. These results will set the stage to develop antimicrobial nanoparticle formulations for applications in chronic wound treatment.

  15. Nitric Oxide and Respiratory Helminthic Diseases

    Directory of Open Access Journals (Sweden)

    Antonio Muro

    2010-01-01

    Full Text Available Nitric oxide (NO is a very simple molecule that displays very important functions both in helminths (mainly those involved in respiratory pathology and in mammalian hosts. In this paper we review four issues related to interaction of NO and lung helminthic diseases. Firstly, we evaluated data available on the NO synthesis and release by helminths and their biological role. Next, we summarized the effect of antigens obtained from different phases of the biological cycle on NO production by host mammalian cells (mainly from human sources. Thirdly, we revised the evaluation of NO on the biological activities and/or the viability of respiratory helminths. Lastly, the deleterious consequences of increased production of NO during helminthic human infection are detailed.

  16. Melatonin and its precursors scavenge nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Y.; Mori, A.; Liburdy, R.; Packer, L.

    1998-12-01

    Nitric oxide (NO) scavenging activity of melatonin, N-acetyl-5-hydroxytryptamine, serotonin, 5-hydroxytryptophan and L-tryptophan was examined by the Griess reaction using flow injection analysis. 1-Hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene(NOC-7) was used as NO generator. The Griess reagent stoichiometrically reacts with NO2-, which was converted by a cadmium-copper reduction column from the stable end products of NO oxidation. Except for tryptophan, all the compounds examined scavenged NO in a dose-dependent manner. Melatonin, which has a methoxy group in the 5-position and an acetyl side chain, exhibited the most potent scavenging activity among the compounds tested. Serotonin, N-acetyl-5-hydroxytryptamine, and 5-hydroxytryptophan, respectively, showed moderate scavenging activity compared to melatonin. Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.

  17. Nitric Oxide Synthase Inhibitors as Antidepressants

    Directory of Open Access Journals (Sweden)

    Vallo Volke

    2010-01-01

    Full Text Available Affective and anxiety disorders are widely distributed disorders with severe social and economic effects. Evidence is emphatic that effective treatment helps to restore function and quality of life. Due to the action of most modern antidepressant drugs, serotonergic mechanisms have traditionally been suggested to play major roles in the pathophysiology of mood and stress-related disorders. However, a few clinical and several pre-clinical studies, strongly suggest involvement of the nitric oxide (NO signaling pathway in these disorders. Moreover, several of the conventional neurotransmitters, including serotonin, glutamate and GABA, are intimately regulated by NO, and distinct classes of antidepressants have been found to modulate the hippocampal NO level in vivo. The NO system is therefore a potential target for antidepressant and anxiolytic drug action in acute therapy as well as in prophylaxis. This paper reviews the effect of drugs modulating NO synthesis in anxiety and depression.

  18. Citric Acid Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  19. The nitric oxide synthase of mouse spermatozoa.

    Science.gov (United States)

    Herrero, M B; Goin, J C; Boquet, M; Canteros, M G; Franchi, A M; Perez Martinez, S; Polak, J M; Viggiano, J M; Gimeno, M A

    1997-07-01

    Nitric oxide synthase (NOS) was evidenced in mature mouse spermatozoa by means of biochemical techniques and Western blot. During 120 min of incubation, 10(7) spermatozoa synthesized 7 +/- 2 pmol of L-[14C]citrulline. Besides, L-citrulline formation depended on the incubation time and on the concentration of L-arginine present in the incubation medium. Different concentrations of N(G)-nitro-L-arginine methyl ester (L-NAME) but not aminoguanidine, inhibited L-[14C]citrulline formation. Western-blot analysis of solubilized sperm proteins revealed a unique band of M(r)=140 kDa with the neural, endothelial and inducible NOS antisera tested. These results provide evidence that mature mouse sperm contains a NOS isoform and that spermatozoa have the potential ability to synthesize NO, suggesting a role for endogenous NO on mammalian sperm function.

  20. Nitric oxide turnover in permeable river sediment

    DEFF Research Database (Denmark)

    Schreiber, Frank; Stief, Peter; Kuypers, Marcel M M;

    2014-01-01

    We measured nitric oxide (NO) microprofiles in relation to oxygen (O2) and all major dissolved N-species (ammonium, nitrate, nitrite, and nitrous oxide [N2O]) in a permeable, freshwater sediment (River Weser, Germany). NO reaches peak concentrations of 0.13 μmol L-1 in the oxic zone and is consumed...... in the oxic-anoxic transition zone. Apparently, NO is produced by ammonia oxidizers under oxic conditions and consumed by denitrification under microoxic conditions. Experimental percolation of sediment cores with aerated surface water resulted in an initial rate of NO production that was 12 times higher than...... the net NO production rate in steady state. This initial NO production rate is in the same range as the net ammonia oxidation rate, indicating that NO is transiently the main product of ammonia oxidizers. Stable isotope labeling experiments with the 15N-labeled chemical NO donor S...

  1. Hypoxia tolerance, nitric oxide, and nitrite

    DEFF Research Database (Denmark)

    Fago, Angela; Jensen, Frank Bo

    2015-01-01

    Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia ...... of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals....... survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance...

  2. Autotrophic Biofilters for Oxidation of Nitric Oxide

    Institute of Scientific and Technical Information of China (English)

    陈建孟; 陈浚; LanceHershman; 王家德; DanielP.Y.Chang

    2004-01-01

    Carbon foam—a kind of new engineering material as packing material was adopted in three biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was developed on the surface of carbon foams using nitrite as its only nitric source. The moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize the thickness of the liquid film. The liquid phase nitrification test was conducted to determine the variability and the potential of performance among the three carbon foam biofilters. The investigation showed that during the NO2-—N inlet concentration of 200 g·L-1·min-1 to 800 g·L-1·min-1, the 24PPC (pores per centimeter) carbon foam biofilter had the greatest potential, achieving the NO2-—N removal efficiency of 94% to 98%. The 8PPC and 18PPC carbon foam biofilters achieved the NO2-—N removal efficiency of 15% to 21% and of 30% to 40%, respectively. The potential for this system to remove NO from a gas stream was shown on the basis of a steady removal efficiency of 41% to 50% which was attained for the 24PPC carbon foam biofilter at specified NO inlet concentration of 66.97 mg·m-3 to 267.86mg·m-3 and an empty-bed residence time of 3.5 min.

  3. Nitric oxide in the psychobiology of mental disorders

    Directory of Open Access Journals (Sweden)

    Altan Eşsizoğlu

    2009-03-01

    Full Text Available Nitric oxide is in a gaseous form and is widespread in the human body. It functions by acting as a secondary messenger in the modulatory activities of neuronal functions of the central nervous system. Nitric oxide is the first identified neurotransmitter of the nontraditional neurotransmitter family.Studies conducted on experimental animals demonstrate that nitric oxide has a neuromodulatory efficacy on the secretions of other neurotransmitters and that it has an effect on learning and memory functions, and on various neuronal mechanisms. Many studies have been conducted to investigate the location of nitric oxide in the central nervous system, its effect on anxiety and depression, its relationship with other neurotransmitters, and also about its role on neurotoxicity. There are clinical studies concerning the level of nitrate, a product of nitric oxide metabolism, and also experimental studies concerning its rewarding effect of alcohol and substance use, in patients with depression and schizophrenia. However, limited studies have been conducted to investigate its relationship with stress, which is an important factor in the etiology of psychiatric disorders. These studies demonstrate that nitric oxide is closely related with stress physiology.Nitric oxide is a neuromodulator, which is frequently being mentioned about nowadays in psychiatry. Clinical and experimental studies play an important role in the psychobiology of psychiatric disorders.

  4. Possible involvement of nitric oxide (NO) signaling pathway in the antidepressant-like effect of MK-801(dizocilpine), a NMDA receptor antagonist in mouse forced swim test.

    Science.gov (United States)

    Dhir, Ashish; Kulkarni, S K

    2008-03-01

    L-arginine-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) is an important signaling pathway involved in depression. With this information, the present study aimed to study the involvement of this signaling pathway in the antidepressant-like action of MK-801 (dizocilpine; N-methyl-d-aspartate receptor antagonist) in the mouse forced-swim test. Total immobility period was recorded in mouse forced swim test for 6 min. MK-801 (5-25 microg/kg., ip) produced a U-shaped curve in reducing the immobility period. The antidepressant-like effect of MK-801 (10 microg/kg, ip) was prevented by pretreatment with L-arginine (750 mg/kg, ip) [substrate for nitric oxide synthase (NOS)]. Pretreatment of mice with 7-nitroindazole (7-NI) (25 mg/kg, ip) [a specific neuronal nitric oxide synthase inhibitor] produced potentiation of the action of subeffective dose of MK-801 (5 microg/kg, ip). In addition, treatment of mice with methylene blue (10 mg/kg, ip) [direct inhibitor of both nitric oxide synthase and soluble guanylate cyclase] potentiated the effect of MK-801 (5 microg/kg, ip) in the forced-swim test. Further, the reduction in the immobility period elicited by MK-801 (10 microg/kg, ip) was also inhibited by pretreatment with sildenafil (5 mg/kg, ip) [phosphodiesterase 5 inhibitor]. The various modulators used in the study and their combination did not produce any changes in locomotor activity per se and in combination with MK-801. MK-801 however, at higher doses (25 microg/kg, ip) produced hyperlocomotion. The results demonstrated the involvement of nitric oxide signaling pathway in the antidepressant-like effect of MK-801 in mouse forced-swim test.

  5. Corrosion studies in fuel element reprocessing environments containing nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Beavers, J A; White, R R; Berry, W E; Griess, J C

    1982-04-01

    Nitric acid is universally used in aqueous fuel element reprocessing plants; however, in the processing scheme being developed by the Consolidated Fuel Reprocessing Program, some of the equipment will be exposed to nitric acid under conditions not previously encountered in fuel element reprocessing plants. A previous report presented corrosion data obtained in hyperazeotropic nitric acid and in concentrated magnesium nitrate solutions used in its preparation. The results presented in this report are concerned with the following: (1) corrosion of titanium in nitric acid; (2) corrosion of nickel-base alloys in a nitric acid-hydrofluoric acid solution; (3) the formation of Cr(VI), which enhances corrosion, in nitric acid solutions; and (4) corrosion of mechanical pipe connectors in nitric acid. The results show that the corrosion rate of titanium increased with the refreshment rate of boiling nitric acid, but the effect diminished rapidly as the temperature decreased. The addition of iodic acid inhibited attack. Also, up to 200 ppM of fluoride in 70% HNO/sub 3/ had no major effect on the corrosion of either titanium or tantalum. In boiling 8 M HNO/sub 3/-0.05 M HF, Inconel 671 was more resistant than Inconel 690, but both alloys experienced end-grain attack. In the case of Inconel 671, heat treatment was very important; annealed and quenched material was much more resistant than furnace-cooled material.The rate of oxidation of Cr(III) to Cr(VI) increased significantly as the nitric acid concentration increased, and certain forms of ruthenium in the solution seemed to accelerate the rate of formation. Mechanical connectors of T-304L stainless steel experienced end-grain attack on the exposed pipe ends, and seal rings of both stainless steel and a titanium alloy (6% Al-4% V) underwent heavy attack in boiling 8 M HNO/sub 3/.

  6. Brain-natriuretic peptide and cyclic guanosine monophosphate as biomarkers of myxomatous mitral valve disease in dogs

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Falk, Bo Torkel; Teerlink, Tom

    2011-01-01

    Elevations in the plasma concentrations of natriuretic peptides correlate with increased severity of myxomatous mitral valve disease (MMVD) in dogs. This study correlates the severity of MMVD with the plasma concentrations of the biomarkers N-terminal fragment of the pro-brain-natriuretic peptide...... (NT-proBNP) and its second messenger, cyclic guanosine monophosphate (cGMP). Furthermore, the l-arginine:asymmetric dimethylarginine (ADMA) ratio was measured as an index of nitric oxide availability. The study included 75 dogs sub-divided into five groups based on severity of MMVD as assessed...... by clinical examination and echocardiography. Plasma NT-proBNP and cGMP concentrations increased with increasing valve dysfunction and were significantly elevated in dogs with heart failure. The cGMP:NT-proBNP ratio decreased significantly in dogs with heart failure, suggesting the development of natriuretic...

  7. Nitric oxide in the nervous system: biochemical, developmental, and neurobiological aspects.

    Science.gov (United States)

    Cossenza, Marcelo; Socodato, Renato; Portugal, Camila C; Domith, Ivan C L; Gladulich, Luis F H; Encarnação, Thaísa G; Calaza, Karin C; Mendonça, Henrique R; Campello-Costa, Paula; Paes-de-Carvalho, Roberto

    2014-01-01

    Nitric oxide (NO) is a very reactive molecule, and its short half-life would make it virtually invisible until its discovery. NO activates soluble guanylyl cyclase (sGC), increasing 3',5'-cyclic guanosine monophosphate levels to activate PKGs. Although NO triggers several phosphorylation cascades due to its ability to react with Fe II in heme-containing proteins such as sGC, it also promotes a selective posttranslational modification in cysteine residues by S-nitrosylation, impacting on protein function, stability, and allocation. In the central nervous system (CNS), NO synthesis usually requires a functional coupling of nitric oxide synthase I (NOS I) and proteins such as NMDA receptors or carboxyl-terminal PDZ ligand of NOS (CAPON), which is critical for specificity and triggering of selected pathways. NO also modulates CREB (cAMP-responsive element-binding protein), ERK, AKT, and Src, with important implications for nerve cell survival and differentiation. Differences in the regulation of neuronal death or survival by NO may be explained by several mechanisms involving localization of NOS isoforms, amount of NO being produced or protein sets being modulated. A number of studies show that NO regulates neurotransmitter release and different aspects of synaptic dynamics, such as differentiation of synaptic specializations, microtubule dynamics, architecture of synaptic protein organization, and modulation of synaptic efficacy. NO has also been associated with synaptogenesis or synapse elimination, and it is required for long-term synaptic modifications taking place in axons or dendrites. In spite of tremendous advances in the knowledge of NO biological effects, a full description of its role in the CNS is far from being completely elucidated.

  8. Adverse experiences with nitric acid at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Durant, W.S.; Craig, D.K.; Vitacco, M.J.; McCormick, J.A.

    1991-06-01

    Nitric acid is used routinely at the Savannah River Site (SRS) in many processes. However, the site has experienced a number of adverse situations in handling nitric acid. These have ranged from minor injuries to personnel to significant explosions. This document compiles many of these events and includes discussions of process upsets, fires, injuries, and toxic effects of nitric acid and its decomposition products. The purpose of the publication is to apprise those using the acid that it is a potentially dangerous material and can react in many ways as demonstrated by SRS experience. 10 refs.

  9. Familial hemiplegic migraine type 2 does not share hypersensitivity to nitric oxide with common types of migraine

    DEFF Research Database (Denmark)

    Hansen, J.M.; Thomsen, L.L.; Marconi, R.

    2008-01-01

    Familial hemiplegic migraine type 2 (FHM-2) and common types of migraine show phenotypic similarities which may indicate a common neurobiological background. The nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a crucial role in migraine pathophysiology. Therefore, we tested...... and area under the curve (AUC) for headache score during an immediate phase (0-120 min) and a delayed phase (2-14 h) after start of infusion. We found no difference in the incidence of reported migraine between FHM-2 patients, 25% (two out of eight), and controls, 0% (0 out of nine) (95% confidence......(VmeanMCA) (P = 0.77) or AUC(STA) (P = 0.53) between FHM-2 patients and controls. GTN infusion failed to induce more migraine in FHM-2 patients than in controls. The pathophysiological pathways underlying migraine headache in FHM-2 may be different from the common types of migraine Udgivelsesdato: 2008/4...

  10. Identification of a novel Arabidopsis thaliana nitric oxide-binding molecule with guanylate cyclase activity in vitro

    KAUST Repository

    Mulaudzi, Takalani

    2011-09-01

    While there is evidence of nitric oxide (NO)-dependent signalling via the second messenger cyclic guanosine 3′,5′-monophosphate (cGMP) in plants, guanylate cyclases (GCs), enzymes that catalyse the formation of cGMP from guanosine 5′-triphosphate (GTP) have until recently remained elusive and none of the candidates identified to-date are NO-dependent. Using both a GC and heme-binding domain specific (H-NOX) search motif, we have identified an Arabidopsis flavin monooxygenase (At1g62580) and shown electrochemically that it binds NO, has a higher affinity for NO than for O 2 and that this molecule can generate cGMP from GTP in vitro in an NO-dependent manner. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  11. Beyond Inflation: A Cyclic Universe Scenario

    CERN Document Server

    Turok, N G; Turok, Neil; Seinhardt, Paul J.

    2005-01-01

    Inflation has been the leading early universe scenario for two decades, and has become an accepted element of the successful `cosmic concordance' model. However, there are many puzzling features of the resulting theory. It requires both high energy and low energy inflation, with energy densities differing by a hundred orders of magnitude. The questions of why the universe started out undergoing high energy inflation, and why it will end up in low energy inflation, are unanswered. Rather than resort to anthropic arguments, we have developed an alternative cosmology, the Cyclic universe, in which the universe exists in a very long-lived attractor state determined by the laws of physics. The model shares inflation's phenomenological successes without requiring an epoch of high energy inflation. Instead, the universe is made homogeneous and flat, and scale-invariant adiabatic perturbations are generated during an epoch of low energy acceleration like that seen today, but preceding the last big bang. Unlike inflat...

  12. Corrosive electrochemistry of jamesonite by cyclic voltammetry

    Institute of Scientific and Technical Information of China (English)

    余润兰; 胡岳华; 邱冠周; 覃文庆

    2004-01-01

    The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mV and S2O23- , SO24- are produced at potential over 470 mV. The anodic peak producing SO24- is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2 S3 appears at pH 9.18.

  13. Bucket foundations under lateral cyclic loading

    DEFF Research Database (Denmark)

    Foglia, Aligi

    -competitive in the energy market. This thesis addresses issues concerning monopod bucket foundations in the hope of providing tools and ideas that could be used to optimize the design of this sub-structure. The work is focussed on the behaviour of bucket foundations under lateral cyclic loading. Other related......To enable a prosperous development of offshore wind energy, economically feasible technologies must be developed. The monopod bucket foundation is likely to become a cost-effective sub-structure for offshore wind turbines and has the potential to make offshore wind more cost...... and propaedeutic topics, such as bucket foundations under transient lateral loading and under monotonic lateral loading, are also investigated. All the scientific work is fundamentally based on small-scale experimental tests of bucket foundations in dense water-saturated sand. The most important scientific...

  14. Extinction in four species cyclic competition

    Science.gov (United States)

    Intoy, Ben; Pleimling, Michel

    2013-08-01

    When four species compete stochastically in a cyclic way, the formation of two teams of mutually neutral partners is observed. In this paper we study through numerical simulations the extinction processes that can take place in this system both in the well mixed case as well as on different types of lattices. The different routes to extinction are revealed by the probability distribution of the domination time, i.e. the time needed for one team to fully occupy the system. If swapping is allowed between neutral partners, then the probability distribution is dominated by very long-lived states where a few very large domains persist, each domain being occupied by a mix of individuals from species that form one of the teams. Many aspects of the possible extinction scenarios are lost when only considering averaged quantities, such as for example the mean domination time.

  15. Protein Misfolding Cyclic Amplification of Infectious Prions.

    Science.gov (United States)

    Moda, Fabio

    2017-01-01

    Transmissible spongiform encephalopathies, or prion diseases, are a group of incurable disorders caused by the accumulation of an abnormally folded prion protein (PrP(Sc)) in the brain. According to the "protein-only" hypothesis, PrP(Sc) is the infectious agent able to propagate the disease by acting as a template for the conversion of the correctly folded prion protein (PrP(C)) into the pathological isoform. Recently, the mechanism of PrP(C) conversion has been mimicked in vitro using an innovative technique named protein misfolding cyclic amplification (PMCA). This technology represents a great tool for studying diverse aspects of prion biology in the field of basic research and diagnosis. Moreover, PMCA can be expanded for the study of the misfolding process associated to other neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal lobar degeneration. © 2017 Elsevier Inc. All rights reserved.

  16. Pyroelectric Harvesters for Generating Cyclic Energy

    Directory of Open Access Journals (Sweden)

    Chun-Ching Hsiao

    2015-04-01

    Full Text Available Pyroelectric energy conversion is a novel energy process which directly transforms waste heat energy from cyclic heating into electricity via the pyroelectric effect. Application of a periodic temperature profile to pyroelectric cells is necessary to achieve temperature variation rates for generating an electrical output. The critical consideration in the periodic temperature profile is the frequency or work cycle which is related to the properties and dimensions of the air layer; radiation power and material properties, as well as the dimensions and structure of the pyroelectric cells. This article aims to optimize pyroelectric harvesters by matching all these requirements. The optimal induced charge per period increases about 157% and the efficient period band decreases about 77%, when the thickness of the PZT cell decreases from 200 μm to 50 μm, about a 75% reduction. Moreover, when using the thinner PZT cell for harvesting the pyroelectric energy it is not easy to focus on a narrow band with the efficient period. However, the optimal output voltage and stored energy per period decrease about 50% and 74%, respectively, because the electrical capacitance of the 50 μm thick pyroelectric cell is about four times greater than that of the 200 μm thick pyroelectric cell. In addition, an experiment is used to verify that the work cycle to be able to critically affect the efficiency of PZT pyroelectric harvesters. Periods in the range between 3.6 s and 12.2 s are useful for harvesting thermal cyclic energy by pyroelectricity. The optimal frequency or work cycle can be applied in the design of a rotating shutter in order to control the heated and unheated periods of the pyroelectric cells to further enhance the amount of stored energy.

  17. Classifying Spaces with Virtually Cyclic Stabilisers for Certain Infinite Cyclic Extensions

    CERN Document Server

    Fluch, Martin

    2010-01-01

    Let G be an infinite cyclic extension, 1 -> B -> G -> Z -> 1, of a group B where the action of Z on the set of conjugacy classes of non-trivial elements of B is free. This class of groups includes certain ascending HNN-extensions with abelian or free base groups, certain wreath products by Z and the soluble Baumslag--Solitar groups BS(1,m) with |m|> 1. We construct a model for Evc(G), the classifying space of G for the family of virtually cyclic subgroups of G, and give bounds for the minimum dimension of Evc(G). We construct a 2-dimensional model for Evc(G) where G is a soluble Baumslag-Solitar BS(1,m) group with |m|>1 and we show that this model for Evc(G) is of minimal dimension.

  18. CYCLIC VECTORS AND CELLULAR INDECOMPOSABLE OPERATORS ON Qp SPACES

    Institute of Scientific and Technical Information of China (English)

    Ye Shanli; Lou Zengjian

    2011-01-01

    We identify the functions whose polynomial multiples are weak* dense in Qp spaces and prove that if |f(z)|≥|g(z)| and g is cyclic in Qp, then f is cyclic in Qp. We also show that the multiplication operator Mz on Qp spaces is cellular indecomposable.

  19. Cyclic Matching Pursuits with Multiscale Time-frequency Dictionaries

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Christensen, Mads Græsbøll

    2010-01-01

    We generalize cyclic matching pursuit (CMP), propose an orthogonal variant, and examine their performance using multiscale time-frequency dictionaries in the sparse approximation of signals. Overall, we find that the cyclic approach of CMP produces signal models that have a much lower approximati...

  20. Development of Pore Pressure and Material Damping during Cyclic Loading

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1994-01-01

    The behaviour of sand during cyclic loading can be characterized as "stabilization", "instant stabilization". "pore pressure buildup" and "liquefaction". The terminologies can be defined exactly by a simple mathematical formulation based on the existence of a cyclic stable state. By introducing a...

  1. Classifying spaces with virtually cyclic stabilizers for linear groups

    DEFF Research Database (Denmark)

    Degrijse, Dieter Dries; Köhl, Ralf; Petrosyan, Nansen

    2015-01-01

    We show that every discrete subgroup of GL(n, ℝ) admits a finite-dimensional classifying space with virtually cyclic stabilizers. Applying our methods to SL(3, ℤ), we obtain a four-dimensional classifying space with virtually cyclic stabilizers and a decomposition of the algebraic K-theory of its...

  2. Classifying spaces with virtually cyclic stabilizers for linear groups

    DEFF Research Database (Denmark)

    Degrijse, Dieter Dries; Köhl, Ralf; Petrosyan, Nansen

    2015-01-01

    We show that every discrete subgroup of GL(n, ℝ) admits a finite-dimensional classifying space with virtually cyclic stabilizers. Applying our methods to SL(3, ℤ), we obtain a four-dimensional classifying space with virtually cyclic stabilizers and a decomposition of the algebraic K-theory of its...

  3. Cyclic-di-GMP and cyclic-di-AMP activate the NLRP3 inflammasome.

    Science.gov (United States)

    Abdul-Sater, Ali A; Tattoli, Ivan; Jin, Lei; Grajkowski, Andrzej; Levi, Assaf; Koller, Beverly H; Allen, Irving C; Beaucage, Serge L; Fitzgerald, Katherine A; Ting, Jenny P-Y; Cambier, John C; Girardin, Stephen E; Schindler, Christian

    2013-10-01

    The cyclic dinucleotides 3'-5'diadenylate (c-diAMP) and 3'-5' diguanylate (c-diGMP) are important bacterial second messengers that have recently been shown to stimulate the secretion of type I Interferons (IFN-Is) through the c-diGMP-binding protein MPYS/STING. Here, we show that physiologically relevant levels of cyclic dinucleotides also stimulate a robust secretion of IL-1β through the NLRP3 inflammasome. Intriguingly, this response is independent of MPYS/STING. Consistent with most NLRP3 inflammasome activators, the response to c-diGMP is dependent on the mobilization of potassium and calcium ions. However, in contrast to other NLRP3 inflammasome activators, this response is not associated with significant changes in mitochondrial potential or the generation of mitochondrial reactive oxygen species. Thus, cyclic dinucleotides activate the NLRP3 inflammasome through a unique pathway that could have evolved to detect pervasive bacterial pathogen-associated molecular patterns associated with intracellular infections.

  4. Importance of nitric oxide in cadmium stress tolerance in crop plants.

    Science.gov (United States)

    Gill, Sarvajeet Singh; Hasanuzzaman, Mirza; Nahar, Kamrun; Macovei, Anca; Tuteja, Narendra

    2013-02-01

    Cadmium (Cd(2+)) is a widespread heavy metal pollutant in the environment with a long biological half-life, originating mainly from industrial processes and phosphate fertilizers. It is easily taken up by plants, resulting in toxicity symptoms, such as chlorosis, wilting, growth reduction, and cell death. This cellular toxicity might result from interactions with vital metabolic pathways, carboxyl or thiol groups of proteins and reactive oxygen species (ROS) burst in plants. Plant exposure even to low concentrations of Cd may lead to cell death but the mechanism of its toxicity is still debatable. Therefore, exploring various ways to improve crop productivity and/or alleviate Cd stress effects is one of the major areas of concern. Nitric oxide (NO) is a hydrophobic gaseous molecule involved in various physiological processes such as germination, root growth, stomatal closure, control of the flowering timing etc. NO also functions as cell signaling molecule in plants and play important roles in the regulation of plant responses to both abiotic and biotic stress conditions. At the molecular level, NO signaling includes protein modification by binding to critical cysteine residues, heme or iron-sulfur centers and tyrosine residue nitration via peroxynitrite formation (ONOO(-)), mobilization of secondary messengers (Ca(2+), cyclic GMP and cyclic ADP-Rib) and modulation of protein kinase activities. Significant research had been done to understand the NO biosynthesis and signaling in plants under stress, but several questions still need to be answered. The present review is focused specifically on the importance of NO as Cd stress modulator in crop plants.

  5. Nitric acid vapor removal by activated, impregnated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Wood, G.O.

    1996-12-31

    Laboratory and industrial workers can be exposed to vapors of nitric acid, especially in accidents, such as spills. Nitric acid can also be a product of incineration for energy production or waste (e.g., CW agent) disposal. Activated carbons containing impregnants for enhancing vapor and gas removal have been tested for effectiveness in removing vapors of nitric acid from air. The nitric acid vapor was generated from concentrated acid solutions and detected by trapping in a water bubbler for pH measurements. Both low and moderate relative humidity conditions were used. All carbons were effective at vapor contact times representative of air-purifying respirator use. One surprising observation was the desorption of low levels of ammonia from impregnated carbons. This was apparently due to residual ammonia from the impregnation processes.

  6. Nitric oxide metabolites in goldfish under normoxic and hypoxic conditions

    DEFF Research Database (Denmark)

    Hansen, Marie N.; Jensen, Frank Bo

    2010-01-01

    Nitric oxide (NO), produced by nitric oxide synthases (NOS enzymes), regulates multiple physiological functions in animals. NO exerts its effects by binding to iron (Fe) of heme groups (exemplified by the activation of soluble guanylyl cyclase) and by S-nitrosylation of proteins – and it is metab......Nitric oxide (NO), produced by nitric oxide synthases (NOS enzymes), regulates multiple physiological functions in animals. NO exerts its effects by binding to iron (Fe) of heme groups (exemplified by the activation of soluble guanylyl cyclase) and by S-nitrosylation of proteins...... levels was assessed from metabolic and respiratory variables. In normoxic goldfish, the concentrations of NO metabolites in plasma and tissues were comparable with values reported in mammals, indicative of similar NOS activity. Exposure to hypoxia [at PO2 (partial pressure of O2) values close...

  7. Inducible nitric oxide synthase mediates bone loss in ovariectomized mice.

    NARCIS (Netherlands)

    Cuzzocrea, S.; Mazzon, E.; Dugo, L.; Genovese, T.; Paola, R. Di; Ruggeri, Z.; Vegeto, E.; Caputi, A.P.; Loo, F.A.J. van de; Puzzolo, D.; Maggi, A.

    2003-01-01

    Several clinical studies have shown that bone loss may be attributed to osteoclast recruitment induced by mediators of inflammation. In different experimental paradigms we have recently demonstrated that estrogen exhibits antiinflammatory activity by preventing the induction of inducible nitric

  8. The Effect of Nitric Oxide Donor in Diabetic Wound Healing

    Directory of Open Access Journals (Sweden)

    N Dashti

    2003-10-01

    Full Text Available Diabetes is characterized by a nitric oxide deficiency at the wound site. Diabetes is a factor that influences all stages of wound healing. In animals with acute experimental diabetes induced by streptozotocin (STZ, the early inflammatory responses after wounding is impaired, fibroblast and endothelial cell proliferation is reduced as well as accumulation of reparative collagen and gain in wound breaking strenght. This study investigated whether exogenous nitric oxide supplimentation with nitric oxide donor DETA NONOate could reverse impaired healing in diabetes. The results suggest nitric oxide donor DETA NONOate can reverse impaired healing associated with diabetes (P<0.001 and urinary nitrate (NO-3 output may reflect the extent of repair in this wound model (P<0.001.

  9. Inducible nitric oxide synthase mediates bone loss in ovariectomized mice.

    NARCIS (Netherlands)

    Cuzzocrea, S.; Mazzon, E.; Dugo, L.; Genovese, T.; Paola, R. Di; Ruggeri, Z.; Vegeto, E.; Caputi, A.P.; Loo, F.A.J. van de; Puzzolo, D.; Maggi, A.

    2003-01-01

    Several clinical studies have shown that bone loss may be attributed to osteoclast recruitment induced by mediators of inflammation. In different experimental paradigms we have recently demonstrated that estrogen exhibits antiinflammatory activity by preventing the induction of inducible nitric oxid

  10. Adhesion Development and the Expression of Endothelial Nitric Oxide Synthase

    Directory of Open Access Journals (Sweden)

    David M. Svinarich

    2001-01-01

    Full Text Available Objective: This study was conducted to determine whether nitric oxide (NO, a potent vasodilator and inhibitor of thrombus formation, is involved in the formation and maintenance of adhesions.

  11. Serum nitric oxide and homocysteine as biomarkers of ectopic pregnancy

    Directory of Open Access Journals (Sweden)

    Kavitha Meiyappan

    2015-02-01

    Full Text Available Background: Aim of current study was to evaluate the role of serum homocysteine and nitric oxide in the diagnosis of ectopic pregnancy. Methods: The study included 32 patients with ruptured ectopic, 29 miscarriage patients and 30 normal pregnant women as controls. Fasting plasma homocysteine, serum folate, vitamin B12 levels and nitric oxide levels were estimated at the time of admission. Results: Plasma homocysteine levels were significantly lower in patients with ectopic pregnancy than normal pregnancy. Nitric oxide levels were significantly lower in patients with abortion. Conclusions: Patients with abortion have decreased circulating nitric oxide levels in serum while those with ectopic pregnancies have decreased homocysteine levels. [Int J Reprod Contracept Obstet Gynecol 2015; 4(1.000: 66-70

  12. Nitric oxide damages neuronal mitochondria and induces apoptosis in neurons

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The cytotoxic effect of nitric oxide on primarily cultured rat cerebellar granule cells was studied,and the mechanisms were discussed.The results showed that nitric oxide donor S-nitroso-N-acetyl-penicillamine (SNAP; 500 μmol/L) could induce apoptosis in immature cultures of cerebellar granule cells.Flow cytometry and HPLC analyses revealed that after treatment with SNAP,the mitochondrial transmembrane potential and the cellular ATP content decreased significantly.Nitric oxide scavenger hemoglobin could effectively prevent the neuronal mitochondria from dysfunction and attenuate apoptosis.The results suggested that nitric oxide activated the apoptotic program by inhibiting the activity of mitochondrial respiratory chain and thus decreasing the cellular ATP content.

  13. Nitric oxide synthase and nitric oxide alterations in chronically stressed rats: a model for nitric oxide in major depressive disorder.

    Science.gov (United States)

    Gao, Shang-Feng; Lu, Yun-Rong; Shi, Li-Gen; Wu, Xue-Yan; Sun, Bo; Fu, Xin-Yan; Luo, Jian-Hong; Bao, Ai-Min

    2014-09-01

    Nitric oxide (NO) and NO synthase-1 (NOS1) are involved in the stress response and in depression. We compared NOS-NO alterations in rats exposed to chronic unpredictable stress (CUS) with alterations in major depressive disorder (MDD) in humans. In the hypothalamus of male CUS rats we determined NOS activity, and in the paraventricular nucleus (PVN) we determined NOS1-immunoreactive (ir) cell densities and co-localization of NOS1 with stress-related neuropeptides corticotropin-releasing hormone (CRH), vasopressin (AVP) or oxytocin (OXT). We measured plasma NO levels and cortisol in male medicine-naïve MDD patients and plasma NO and corticosterone (CORT) in CUS rats. In the CUS rat total NOS activity in the hypothalamus (P=0.018) and NOS1-ir cell density in the PVN were both significantly decreased (P=0.018), while NOS1 staining was mainly expressed in OXT-ir neurons in this nucleus. Interestingly, plasma NO levels were significantly increased both in male CUS rats (P=0.001) and in male MDD patients (Pdepression.

  14. Potassium softens vascular endothelium and increases nitric oxide release

    OpenAIRE

    2009-01-01

    In the presence of aldosterone, plasma sodium in the high physiological range stiffens endothelial cells and reduces the release of nitric oxide. We now demonstrate effects of extracellular potassium on stiffness of individual cultured bovine aortic endothelial cells by using the tip of an atomic force microscope as a mechanical nanosensor. An acute increase of potassium in the physiological range swells and softens the endothelial cell and increases the release of nitric oxide. A high physio...

  15. Serum nitric oxide and homocysteine as biomarkers of ectopic pregnancy

    OpenAIRE

    Kavitha Meiyappan; Pooja Dhiman; Soundravally Rajendiren; Krishnalatha Thayagarajan; Soundara Raghavan S

    2015-01-01

    Background: Aim of current study was to evaluate the role of serum homocysteine and nitric oxide in the diagnosis of ectopic pregnancy. Methods: The study included 32 patients with ruptured ectopic, 29 miscarriage patients and 30 normal pregnant women as controls. Fasting plasma homocysteine, serum folate, vitamin B12 levels and nitric oxide levels were estimated at the time of admission. Results: Plasma homocysteine levels were significantly lower in patients with ectopic pregnancy t...

  16. Diamagnetism and Strucure of Nitric Acid-Treated Bulk Polyethylene

    OpenAIRE

    Ania, F.; Baltá Calleja, F. J.; Cagiao, M.E.

    1982-01-01

    An alternative procedure to examine the nature of the end product of nitric-acid-treated bulk polyethylene involving the measurement of the diamagnetic susceptibility is reported. This simple non-destructive method complements previous results obtained by means of IR spectroscopy. Thus after selectively removing the surface layer of the polyethylene lamellae with nitric acid (t > 50h) the diamagnetic susceptibility substantially decreases to values wich are consistent with tilted paraff...

  17. Acute chemical pneumonitis caused by nitric acid inhalation: case report

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Hyung Shim; Lee, In Jae; Ko, Eun Young; Lee, Jae Young; Kim, Hyun Beom; Hwang, Dae Hyun; Lee, Kwan Seop; Lee, Yul; Bae, Sang Hoon [Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of)

    2003-06-01

    Chemical pneumonitis induced by nitric acid inhalation is a rare clinical condition. The previously reported radiologic findings of this disease include acute permeability pulmonary edema, delayed bronchiolitis obliterans, and bronchiectasis. In very few published rare radiologic reports has this disease manifested as acute alveolar injury; we report a case of acute chemical pneumonitis induced by nitric acid inhalation which at radiography manifested as bilateral perihilar consolidation and ground-glass attenuation, suggesting acute alveolar injury.

  18. Isolation and Partial Characterization of a Cyclic GMP-Dependent Cyclic GMP-Specific Phosphodiesterase from Dictyostelium discoideum

    NARCIS (Netherlands)

    Bulgakov, Roman; Haastert, Peter J.M. van

    1983-01-01

    The cellular slime mold, Dictyostelium discoideum, contains at least two classes of phosphodiesterase activity. One class of enzymes hydrolyses cyclic AMP (cAMP) and cyclic GMP (cGMP) with approximately equal rates. Another enzyme, which is less than 5% of the total activity, specifically hydrolyses

  19. Inter-rater reliability of cyclic and non-cyclic task assessment using the hand activity level in appliance manufacturing.

    Science.gov (United States)

    Paulsen, Robert; Schwatka, Natalie; Gober, Jennifer; Gilkey, David; Anton, Dan; Gerr, Fred; Rosecrance, John

    2014-01-01

    This study evaluated the inter-rater reliability of the American Conference of Governmental Industrial Hygienists (ACGIH(®)) hand activity level (HAL), an observational ergonomic assessment method used to estimate physical exposure to repetitive exertions during task performance. Video recordings of 858 cyclic and non-cyclic appliance manufacturing tasks were assessed by sixteen pairs of raters using the HAL visual-analog scale. A weighted Pearson Product Moment-Correlation Coefficient was used to evaluate the agreement between the HAL scores recorded by each rater pair, and the mean weighted correlation coefficients for cyclic and non-cyclic tasks were calculated. Results indicated that the HAL is a reliable exposure assessment method for cyclic (r̄-bar w = 0.69) and non-cyclic work tasks (r̄-bar w = 0.68). When the two reliability scores were compared using a two-sample Student's t-test, no significant difference in reliability (p = 0.63) between these work task categories was found. This study demonstrated that the HAL may be a useful measure of exposure to repetitive exertions during cyclic and non-cyclic tasks.

  20. Comparison the effects of nitric oxide and spermidin pretreatment on alleviation of salt stress in chamomile plant (Matricaria recutita L.

    Directory of Open Access Journals (Sweden)

    Fazelian Nasrin

    2012-08-01

    Full Text Available Salt stress is an important environmental stress that produces reactive oxygen species in plants and causes oxidative injuries. In this investigation, salt stress reduced the shoot and root length, while increased the content of malondealdehyde, Hydrogen peroxide, and the activity of Ascorbate peroxidase andguaiacol peroxidase. Pretreatment of chamomile plants under salt stress with sodium nitroprussideand Spermidin caused enhancement of growth parameters and reduction of malondealdehyde and Hydrogen peroxide content. Pretreatment of plants with sodium nitroprusside remarkably increased Ascorbate peroxidase activity, while Spermidin pre-treatment significantly increased guaiacol peroxidase activity. Application of sodium nitroprusside or Spermidin with Methylene blue which is known to block cyclic guanosine monophosphate signaling pathway, reduced the protective effects of sodium nitroprussideand Spermidin in plants under salinity condition. The result of this study indicated that Methylene blue could partially and entirely abolish the protective effect of Nitric oxide on some physiological parameter. Methylene blue also has could reduce the alleviation effect of Spermidin on some of parameters in chamomile plant under salt stress, so with comparing the results of this study it seems that Spermidin probably acts through Nitric oxide pathway, but the use of 2-4- carboxyphenyl- 4,4,5,5- tetramethyl-imidazoline-1-oxyl-3-oxide is better to prove.

  1. Increased contribution of L-arginine-nitric oxide pathway in aorta of mice lacking the gene for vimentin.

    Science.gov (United States)

    Zhang, J; Henrion, D; Ebrahimian, T; Benessiano, J; Colucci-Guyon, E; Langa, F; Lévy, B I; Boulanger, C M

    2001-10-01

    Experiments were designed to investigate endothelial function in the aorta of mice lacking the gene for the cytoskeleton protein vimentin (vim -/- ). Rings with and without endothelium from wild-type (vim +/+ ), heterozygous (vim +/- ), and homozygous (vim -/- ) mice were suspended in organ chambers to record of changes in isometric tension. During phenylephrine contraction, acetylcholine evoked comparable endothelium-dependent relaxations in the three groups. In the presence of Nomega-nitro-L-arginine, acetylcholine caused endothelium-dependent contractions, which were greater in vim -/- than in vim +/+ and vim +/- aortas. Indomethacin did not affect relaxation to acetylcholine in vim +/+ or in vim +/-, but it significantly increased the maximal response in vim -/- (67 +/- 7 vs. 102 +/- 4%). Response to acetylcholine in vim -/- aortas was not affected by cyclooxygenase type 2 inhibitor NS-398, the thromboxane receptor antagonist SQ-29,548, or superoxide dismutase. Relaxations to sodium nitroprusside were not different between vim +/+ and vim -/- mice and were not affected by cyclooxygenase inhibition. Cyclic guanosine monophosphate levels, which were increased to a comparable level by acetylcholine in vim +/+ and vim -/-, were augmented by indomethacin in vim -/- aortas but not in vim +/+ aortas. Expression of endothelial nitric oxide synthase was not different between vim +/+ and vim -/- preparations. These results suggest that despite comparable endothelium-dependent responses to acetylcholine, endothelial cells from vim -/- mice release a cyclooxygenase product that compensates the augmented contribution of nitric oxide.

  2. Cyclic nucleotide specific phosphodiesterases of Leishmania major

    Directory of Open Access Journals (Sweden)

    Linder Markus

    2006-03-01

    Full Text Available Abstract Background Leishmania represent a complex of important human pathogens that belong to the systematic order of the kinetoplastida. They are transmitted between their human and mammalian hosts by different bloodsucking sandfly vectors. In their hosts, the Leishmania undergo several differentiation steps, and their coordination and optimization crucially depend on numerous interactions between the parasites and the physiological environment presented by the fly and human hosts. Little is still known about the signalling networks involved in these functions. In an attempt to better understand the role of cyclic nucleotide signalling in Leishmania differentiation and host-parasite interaction, we here present an initial study on the cyclic nucleotide-specific phosphodiesterases of Leishmania major. Results This paper presents the identification of three class I cyclic-nucleotide-specific phosphodiesterases (PDEs from L. major, PDEs whose catalytic domains exhibit considerable sequence conservation with, among other, all eleven human PDE families. In contrast to other protozoa such as Dictyostelium, or fungi such as Saccharomyces cerevisiae, Candida ssp or Neurospora, no genes for class II PDEs were found in the Leishmania genomes. LmjPDEA contains a class I catalytic domain at the C-terminus of the polypeptide, with no other discernible functional domains elsewhere. LmjPDEB1 and LmjPDEB2 are coded for by closely related, tandemly linked genes on chromosome 15. Both PDEs contain two GAF domains in their N-terminal region, and their almost identical catalytic domains are located at the C-terminus of the polypeptide. LmjPDEA, LmjPDEB1 and LmjPDEB2 were further characterized by functional complementation in a PDE-deficient S. cerevisiae strain. All three enzymes conferred complementation, demonstrating that all three can hydrolyze cAMP. Recombinant LmjPDEB1 and LmjPDEB2 were shown to be cAMP-specific, with Km values in the low micromolar range

  3. Nitric oxide negatively regulates mammalian adult neurogenesis

    Science.gov (United States)

    Packer, Michael A.; Stasiv, Yuri; Benraiss, Abdellatif; Chmielnicki, Eva; Grinberg, Alexander; Westphal, Heiner; Goldman, Steven A.; Enikolopov, Grigori

    2003-08-01

    Neural progenitor cells are widespread throughout the adult central nervous system but only give rise to neurons in specific loci. Negative regulators of neurogenesis have therefore been postulated, but none have yet been identified as subserving a significant role in the adult brain. Here we report that nitric oxide (NO) acts as an important negative regulator of cell proliferation in the adult mammalian brain. We used two independent approaches to examine the function of NO in adult neurogenesis. In a pharmacological approach, we suppressed NO production in the rat brain by intraventricular infusion of an NO synthase inhibitor. In a genetic approach, we generated a null mutant neuronal NO synthase knockout mouse line by targeting the exon encoding active center of the enzyme. In both models, the number of new cells generated in neurogenic areas of the adult brain, the olfactory subependyma and the dentate gyrus, was strongly augmented, which indicates that division of neural stem cells in the adult brain is controlled by NO and suggests a strategy for enhancing neurogenesis in the adult central nervous system.

  4. Biomimetic and microbial reduction of nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Potter, W.T.; Le, U.; Ronda, S. [Univ. of Tulsa, OK (United States)] [and others

    1995-12-31

    The biomimetic reduction of nitric oxide (NO) to nitrous oxide (N{sub 2}O) by dithiothreitol in the presence of cyanocobalamin and cobalt-centered porphyrins has been investigated. Reactions were monitored directly using Fourier Transform Infrared (FTIR) Spectroscopy vapor-phase spectra. Reaction rates were twofold faster for the corrin than for the cobalt-centered porphyrins. The stoichiometry showed the loss of two molecules of NO per molecule of N{sub 2}O produced. We have also demonstrated that the facultative anaerobe and chemoautotroph, Thiobacillus denitrificans, can be cultured anoxically in batch reactors using NO as a terminal electron acceptor with reduction to elemental nitrogen (N{sub 2}). We have proposed that the concentrated stream of NO{sub x}, as obtained from certain regenerable processes for the gas desulfurization and NO{sub x} removal, could be converted to N{sub 2} for disposal by contact with a culture of T. denitrificans. Four heterotrophic bacteria have also been identified that may be grown in batch cultures with succinate, yeast extract, or heat and alkali pretreated sewage sludge as carbon and energy sources and NO as a terminal electron acceptor. These are Paracoccus dentrificans, Pseudomonas denitrificans, Alcaligens denitrificans, and Thiophaera pantotropha.

  5. Superhydrophobic nitric oxide-releasing xerogels.

    Science.gov (United States)

    Storm, Wesley L; Youn, Jonghae; Reighard, Katelyn P; Worley, Brittany V; Lodaya, Hetali M; Shin, Jae Ho; Schoenfisch, Mark H

    2014-08-01

    Superhydrophobic nitric oxide (NO)-releasing xerogels were prepared by spray-coating a fluorinated silane/silica composite onto N-diazeniumdiolate NO donor-modified xerogels. The thickness of the superhydrophobic layer was used to extend NO release durations from 59 to 105h. The resulting xerogels were stable, maintaining superhydrophobicity for up to 1month (the longest duration tested) when immersed in solution, with no leaching of silica or undesirable fragmentation detected. The combination of superhydrophobicity and NO release reduced viable Pseudomonas aeruginosa adhesion by >2-logs. The killing effect of NO was demonstrated at longer bacterial contact times, with superhydrophobic NO-releasing xerogels resulting in 3.8-log reductions in adhered viable bacteria vs. controls. With no observed toxicity to L929 murine fibroblasts, NO-releasing superhydrophobic membranes may be valuable antibacterial coatings for implants as they both reduce adhesion and kill bacteria that do adhere. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Hemoglobin: A Nitric-Oxide Dioxygenase

    Directory of Open Access Journals (Sweden)

    Paul R. Gardner

    2012-01-01

    Full Text Available Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs. Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.

  7. Nitric oxide and teratogenesis: an update.

    Science.gov (United States)

    Tiboni, Gian Mario; Ponzano, Adalisa

    2014-01-01

    Nitric oxide (NO), generated by NO synthase (NOS) enzymes, is an important bioactive molecule involved in the regulation of several biological phenomena that are crucial for organogenesis, including gene expression, cell growth, matrix remolding, proliferation, differentiation and apoptosis. The expression of NOS isoforms in embryonic tissues is temporally and spatially regulated, and disruption of endogenous NO can lead to developmental defects. Maternal treatment with pan NOS inhibitors during early organogenesis caused severe malformations of the axial skeleton. In utero exposure during the fetal period induced limb reduction defects of vascular origin. Knock-out mice have been used to define the role of the various NOS isoforms on the origin of the abnormal development. Cardiovascular malformations, limb reduction defects, reduced growth and reduced survival have been observed in knock-out mice with targeted disruption of endothelial NOS (eNOS). Limited morphological changes were observed in mice lacking inducible NOS (iNOS) or neuronal NOS n(NOS). Results obtained with in vitro studies suggest that optimal levels of NO are required for neural tube closure. Disregulation of NO production was also recently proposed as a contributing mechanism in the origin of malformations associated with exposure to known environmental teratogens, such as valproic acid, thalidomide, copper deficiency, and diabetes.

  8. Dietary Nitrate, Nitric Oxide, and Cardiovascular Health.

    Science.gov (United States)

    Bondonno, Catherine P; Croft, Kevin D; Hodgson, Jonathan M

    2016-09-09

    Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine-NO-synthase pathway and the recently discovered enterosalivary nitrate-nitrite-NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate.

  9. Nitric oxide and cardiovascular risk factors

    Directory of Open Access Journals (Sweden)

    Livio Dai Cas

    2007-06-01

    Full Text Available The endothelium is a dynamic organ with many properties that takes part in the regulation of the principal mechanisms of vascular physiology. Its principal functions include the control of blood-tissue exchange and permeability, the vascular tonus, and the modulation of inflammatory or coagulatory mechanisms. Many vasoactive molecules, produced by the endothelium, are involved in the control of these functions. The most important is nitric oxide (NO, a gaseous molecule electrically neutral with an odd number of electrons that gives the molecule chemically reactive radical properties. Already known in the twentieth century, NO, sometimes considered as a dangerous molecule, recently valued as an important endogenous vasodilator factor. Recently, it was discovered that it is involved in several physiological mechanisms of endothelial protection (Tab. I. In 1992, Science elected it as “molecule of the year”; 6 yrs later three American researchers (Louis Ignarro, Robert Furchgott and Fried Murad obtained a Nobel Prize for Medicine and Physiology “for their discoveries about NO as signal in the cardiovascular system”.

  10. Nitric Oxide Synthases in Heart Failure

    Science.gov (United States)

    Carnicer, Ricardo; Crabtree, Mark J.; Sivakumaran, Vidhya

    2013-01-01

    Abstract Significance: The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca2+ homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology. Recent Advances: Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease. Critical Issues: Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress. Future Directions: Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance. Antioxid. Redox Signal. 18, 1078–1099. PMID:22871241

  11. Concentrations of Nitric Oxide in Rat Brain Tissues after Diffuse Brain Injury and Neuroprotection by the Selective Inducible Nitric Oxide Synthase Inhibitor Aminoguanidine

    Institute of Scientific and Technical Information of China (English)

    Yi-bao Wang; Shao-wu Ou; Guang-yu Li; Yun-hui Liu

    2005-01-01

    @@ To investigate the effects of nitric oxide (NO) and the selective inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (AG) on trauma, we explored the concentrations of nitric oxide in rat brain tissues at different time stamps after diffuse brain injury (DBI) with or without AG treatment.

  12. Evaluation and Control of Cyclic Variation in Spark Ignited Engines by a Thermodynic Model

    Institute of Scientific and Technical Information of China (English)

    纪常伟; 张红光

    2004-01-01

    An evaluation method of engine cyclic variation is proposed based on fuzzy mathematics concept. The degree of engine cyclic variation is divided into 4 levels: stable, slight variation, moderate variation and serious variation based on the statistic standard deviation of residual gas temperatures within the specified simulation cycles and the function of cyclic variation is also inducted for the cyclic variation control. Because the degree of engine cyclic variation can be estimated qualitatively, the effective control means can be applied to appease the undesired cyclic variation. Simulation result shows that for a very serious cyclic variation through the proper adjustment of the spark angle and the cyclic variation will disappear.

  13. Protein misfolding cyclic amplification of infectious prions.

    Science.gov (United States)

    Morales, Rodrigo; Duran-Aniotz, Claudia; Diaz-Espinoza, Rodrigo; Camacho, Manuel V; Soto, Claudio

    2012-06-28

    Prions are proteinaceous infectious agents responsible for the transmission of prion diseases. The lack of a procedure for cultivating prions in the laboratory has been a major limitation to the study of the unorthodox nature of this infectious agent and the molecular mechanism by which the normal prion protein (PrP(C)) is converted into the abnormal isoform (PrP(Sc)). Protein misfolding cyclic amplification (PMCA), described in detail in this protocol, is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA involves incubating materials containing minute amounts of infectious prions with an excess of PrP(C) and boosting the conversion by cycles of sonication to fragment the converting units, thereby leading to accelerated prion replication. PMCA is able to detect the equivalent of a single molecule of infectious PrP(Sc) and propagate prions that maintain high infectivity, strain properties and species specificity. A single PMCA assay takes little more than 3 d to replicate a large amount of prions, which could take years in an in vivo situation. Since its invention 10 years ago, PMCA has helped to answer fundamental questions about this intriguing infectious agent and has been broadly applied in research areas that include the food industry, blood bank safety and human and veterinary disease diagnosis.

  14. Beyond Inflation:. A Cyclic Universe Scenario

    Science.gov (United States)

    Turok, Neil; Steinhardt, Paul J.

    2005-08-01

    Inflation has been the leading early universe scenario for two decades, and has become an accepted element of the successful 'cosmic concordance' model. However, there are many puzzling features of the resulting theory. It requires both high energy and low energy inflation, with energy densities differing by a hundred orders of magnitude. The questions of why the universe started out undergoing high energy inflation, and why it will end up in low energy inflation, are unanswered. Rather than resort to anthropic arguments, we have developed an alternative cosmology, the cyclic universe [1], in which the universe exists in a very long-lived attractor state determined by the laws of physics. The model shares inflation's phenomenological successes without requiring an epoch of high energy inflation. Instead, the universe is made homogeneous and flat, and scale-invariant adiabatic perturbations are generated during an epoch of low energy acceleration like that seen today, but preceding the last big bang. Unlike inflation, the model requires low energy acceleration in order for a periodic attractor state to exist. The key challenge facing the scenario is that of passing through the cosmic singularity at t = 0. Substantial progress has been made at the level of linearised gravity, which is reviewed here. The challenge of extending this to nonlinear gravity and string theory remains.

  15. Thermophoresis of cyclic oligosaccharides in polar solvents.

    Science.gov (United States)

    Eguchi, Kazuya; Niether, Doreen; Wiegand, Simone; Kita, Rio

    2016-09-01

    Cyclodextrins are cyclic oligosaccharides which are interesting as drug delivery systems, because they can be used as containers for pharmaceutical substances. We studied the Ludwig-Soret effect of [Formula: see text]-, [Formula: see text]-, [Formula: see text]- and methyl-[Formula: see text]-cyclodextrin in water and formamide by infrared thermal diffusion forced Rayleigh scattering (IR-TDFRS). In water the Soret coefficient, S T, of [Formula: see text]-, [Formula: see text]- and [Formula: see text]-cyclodextrin increases with increasing temperature and shows a sign change from negative to positive around T = 35 (°) C, while S T of methyl-[Formula: see text]-cyclodextrin is positive in the entire investigated temperature. In formamide S T-values of all cyclodextrins coincide and show a slight decrease with temperature. We discuss the obtained results and relate the S T-values to the different hydrogen bonding capabilities of the cyclodextrins and the used solvents. It turns out that the change of S T with temperature correlates with the partition coefficient, logP, which indicates that more hydrophilic substances show a more pronounced temperature sensitivity of S T. Additionally we obtained a surprising result measuring the refractive index contrast factor with temperature, [Formula: see text] of cyclodextrins in formamide, which might be explained by a complex formation between cyclodextrins and formamide.

  16. Cyclic voltammetry of fast conducting electrocatalytic films.

    Science.gov (United States)

    Costentin, Cyrille; Savéant, Jean-Michel

    2015-07-15

    In the framework of contemporary energy challenges, cyclic voltammetry is a particularly useful tool for deciphering the kinetics of catalytic films. The case of fast conducting films is analyzed, whether conduction is of the ohmic type or proceeds through rapid electron hopping. The rate-limiting factors are then the diffusion of the substrate in solution and through the film as well as the catalytic reaction itself. The dimensionless combination of the characteristics of these factors allows reducing the number of actual parameters to a maximum of two. The kinetics of the system may then be fully analyzed with the help of a kinetic zone diagram. Observing the variations of the current-potential responses with operational parameters such as film thickness, the potential scan rate and substrate concentration allows a precise assessment of the interplay between these factors and of the values of the rate controlling factors. A series of thought experiments is described in order to render the kinetic analysis more palpable.

  17. Noise-guided evolution within cyclical interactions

    CERN Document Server

    Perc, Matjaz

    2007-01-01

    We study a stochastic predator-prey model on a square lattice, where each of the six species has two superior and two inferior partners. The invasion probabilities between species depend on the predator-prey pair and are supplemented by Gaussian noise. Conditions are identified that warrant the largest impact of noise on the evolutionary process, and the results of Monte Carlo simulations are qualitatively reproduced by a four-point cluster dynamical mean-field approximation. The observed noise-guided evolution is deeply routed in short-range spatial correlations, which is supported by simulations on other host lattice topologies. Our findings are conceptually related to the coherence resonance phenomenon in dynamical systems via the mechanism of threshold duality. We also show that the introduced concept of noise-guided evolution via the exploitation of threshold duality is not limited to predator-prey cyclical interactions, but may apply to models of evolutionary game theory as well, thus indicating its app...

  18. Property Testing for Cyclic Groups and Beyond

    CERN Document Server

    Gall, Francois Le

    2011-01-01

    This paper studies the problem of testing if an input (Gamma,*), where Gamma is a finite set of unknown size and * is a binary operation over Gamma given as an oracle, is close to a specified class of groups. Friedl et al. [Efficient testing of groups, STOC'05] have constructed an efficient tester using poly(log|Gamma|) queries for the class of abelian groups. We focus in this paper on subclasses of abelian groups, and show that these problems are much harder: Omega(|Gamma|^{1/6}) queries are necessary to test if the input is close to a cyclic group, and Omega(|Gamma|^c) queries for some constant c are necessary to test more generally if the input is close to an abelian group generated by k elements, for any fixed integer k>0. We also show that knowledge of the size of the ground set Gamma helps only for k=1, in which case we construct an efficient tester using poly(log|Gamma|) queries; for any other value k>1 the query complexity remains Omega(|Gamma|^c). All our upper and lower bounds hold for both the edit...

  19. Coarsening and biodiversity in cyclically competing species

    Science.gov (United States)

    Intoy, Ben; Pleimling, Michel

    2014-03-01

    When four species compete stochastically in a cyclic way, the formation of two teams of mutually neutral partners is observed. We study through numerical simulations the extinction processes that can take place in this system both in the well mixed case as well as on different types of lattices. The different routes to extinction are revealed by the probability distribution of the domination time, i.e. the time needed for one team to fully occupy the system. If swapping is allowed between neutral partners, then the probability distribution is dominated by very long-lived states where a few very large domains persist, each domain being occupied by a mix of individuals from species that form one of the teams. Many aspects of the possible extinction scenarios are lost when only considering averaged quantities as for example the mean domination time. We also discuss some results for a model where species, that compete in Rock-Paper-Scissor fashion, have mixed strategies rather than pure strategies. We compare the case with mixed strategy to the pure strategy case and look at similarities and differences. This work is supported by the US National Science Foundation through grant DMR-1205309.

  20. The reduction potential of nitric oxide (NO) and its importance to NO biochemistry.

    Science.gov (United States)

    Bartberger, Michael D; Liu, Wei; Ford, Eleonora; Miranda, Katrina M; Switzer, Christopher; Fukuto, Jon M; Farmer, Patrick J; Wink, David A; Houk, Kendall N

    2002-08-20

    A potential of about -0.8 (+/-0.2) V (at 1 M versus normal hydrogen electrode) for the reduction of nitric oxide (NO) to its one-electron reduced species, nitroxyl anion (3NO-) has been determined by a combination of quantum mechanical calculations, cyclic voltammetry measurements, and chemical reduction experiments. This value is in accord with some, but not the most commonly accepted, previous electrochemical measurements involving NO. Reduction of NO to 1NO- is highly unfavorable, with a predicted reduction potential of about -1.7 (+/-0.2) V at 1 M versus normal hydrogen electrode. These results represent a substantial revision of the derived and widely cited values of +0.39 V and -0.35 V for the NO/3NO- and NO/1NO- couples, respectively, and provide support for previous measurements obtained by electrochemical and photoelectrochemical means. With such highly negative reduction potentials, NO is inert to reduction compared with physiological events that reduce molecular oxygen to superoxide. From these reduction potentials, the pKa of 3NO- has been reevaluated as 11.6 (+/-3.4). Thus, nitroxyl exists almost exclusively in its protonated form, HNO, under physiological conditions. The singlet state of nitroxyl anion, 1NO-, is physiologically inaccessible. The significance of these potentials to physiological and pathophysiological processes involving NO and O2 under reductive conditions is discussed.

  1. Nitric Oxide Detection with Glassy Carbon Electrodes Coated with Charge-different Polymer Films

    Directory of Open Access Journals (Sweden)

    Jianping Lei

    2005-04-01

    Full Text Available Trace amounts of nitric oxide (NO have been determined in aqueous phosphate buffersolutions (pH=7.4 by using a glassy carbon electrode coated with three charge-different polymerfilms. The glassy carbon electrode was coated first with negatively charged Nafion film containingtetrakis(pentafluorophenylporphyrin iron(III chloride (Fe(IIITPFPP as the NO oxidation catalyst,and then with positively charged poly(acrylamide-co-diallyldimethylammonium chloride (PADDAand with neutral poly(dimethylsiloxane (silicone at the outermost layer. This polymer-coatedelectrode showed an excellent selectivity towards NO against possible concomitants in blood such asnitrite, ascorbic acid, uric acid, and dopamine. All current ratios between each concomitant and NOat the cyclic voltammogram was in 10-3 ~ 10-4. This type of electrode showed a detection limit of80 nM for NO. It was speculated from the electrochemical study in methanol that high-valent oxoiron(IV of Fe(TPFPP participated in the catalytic oxidation of NO.

  2. Sucrose-induced analgesia in mice: Role of nitric oxide and opioid receptor-mediated system

    Directory of Open Access Journals (Sweden)

    Abtin Shahlaee

    2013-01-01

    Full Text Available Background: The mechanism of action of sweet substance-induced analgesia is thought to involve activation of the endogenous opioid system. The nitric oxide (NO pathway has a pivotal role in pain modulation of analgesic compounds such as opioids. Objectives: We investigated the role of NO and the opioid receptor-mediated system in the analgesic effect of sucrose ingestion in mice. Materials and Methods: We evaluated the effect of intraperitoneal administration of 10 mg/kg of NO synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME and 20 mg/kg of opioid receptor antagonist, naltrexone on the tail flick response in sucrose ingesting mice. Results: Sucrose ingestion for 12 days induced a statistically significant increase in the latency of tail flick response which was unmodified by L-NAME, but partially inhibited by naltrexone administration. Conclusions: Sucrose-induced nociception may be explained by facilitating the release of endogenous opioid peptides. Contrary to some previously studied pain models, the NO/cyclic guanosine monophosphate (cGMP pathway had no role in thermal hyperalgesia in our study. We recommend further studies on the involvement of NO in other animals and pain models.

  3. Telmisartan Activates Endothelial Nitric Oxide Synthase via Ser1177 Phosphorylation in Vascular Endothelial Cells

    Science.gov (United States)

    Myojo, Masahiro; Nagata, Daisuke; Fujita, Daishi; Kiyosue, Arihiro; Takahashi, Masao; Satonaka, Hiroshi; Morishita, Yoshiyuki; Akimoto, Tetsu; Nagai, Ryozo; Komuro, Issei; Hirata, Yasunobu

    2014-01-01

    Because endothelial nitric oxide synthase (eNOS) has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177) in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172) and eNOS and the concentration of intracellular guanosine 3′,5′-cyclic monophosphate (cGMP). Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK) inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling. PMID:24827148

  4. Telmisartan activates endothelial nitric oxide synthase via Ser1177 phosphorylation in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Masahiro Myojo

    Full Text Available Because endothelial nitric oxide synthase (eNOS has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177 in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172 and eNOS and the concentration of intracellular guanosine 3',5'-cyclic monophosphate (cGMP. Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.

  5. Nitric oxide inhibits larval settlement in Amphibalanus amphitrite cyprids by repressing muscle locomotion and molting

    KAUST Repository

    Zhang, Gen

    2015-08-28

    Nitric oxide (NO) is a universal signaling molecule and plays a negative role in the metamorphosis of many biphasic organisms. Recently, the NO/NO (cyclic guanosine monophosphate) signaling pathway was reported to repress larval settlement in the barnacle Amphibalanus amphitrite. To understand the underlying molecular mechanism, we analyzed changes in the proteome of A. amphitrite cyprids in response to different concentrations of the NO donor sodium nitroprusside (SNP; 62.5, 250 and 1000 μM) using a label-free proteomics method. Compared with the control, the expression of 106 proteins differed in all three treatments. These differentially expressed proteins were assigned to 13 pathways based on KEGG pathway enrichment analysis. SNP treatment stimulated the expression of heat shock proteins and arginine kinase, which are functionally related to NO synthases, increased the expression levels of glutathione transferases for detoxification, and activated the iron-mediated fatty acid degradation pathway and the citrate cycle through ferritin. Moreover, NO repressed the level of myosins and cuticular proteins, which indicated that NO might inhibit larval settlement in A. amphitrite by modulating the process of muscle locomotion and molting.

  6. A novel aphrodisiac compound from an orchid that activates nitric oxide synthases.

    Science.gov (United States)

    Subramoniam, A; Gangaprasad, A; Sureshkumar, P K; Radhika, J; Arun, K B; Arun, B K

    2013-01-01

    Nitric oxide (NO) is known to have roles in several crucial biological functions including vasodilation and penile erection. There are neuronal, endothelial and inducible NO synthases that influence the levels of NO in tissues and blood. NO activates guanylate cyclase and thereby increases the levels of cyclic GMP (cGMP). Viagra (sildenafil), a top selling drug in the world for erectile dysfunction, inhibits phosphodiesterase-5, which hydrolyses cGMP to GMP. Thus, it fosters an NO-mediated increase in the levels of cGMP, which mediates erectile function. Here, we show the aphrodisiac activity of a novel chemical isolate from the flowers of an epiphytic orchid, Vanda tessellata (Roxb.) ex Don, which activates neuronal and endothelial, but not inducible, NO synthases. The aphrodisiac activity is caused by an increase in the level of NO in corpus cavernosum. The drug increases blood levels of NO as early as 30 min after oral administration. The active compound was isolated by column chromatography. Based on the spectral data, the active compound is found to be a new compound, 2,7,7-tri methyl bicyclo [2.2.1] heptane. We anticipate that our findings could lead to the development of a commercially viable and valuable drug for erectile dysfunction.

  7. Suppression of endothelin-3-induced nitric oxide synthesis by triglyceride in human endothelial cells.

    Science.gov (United States)

    Minami, M; Yokokawa, K; Kohno, M; Yasunari, K; Yoshikawa, J

    1998-01-01

    Reduced endothelium-derived nitric oxide (NO) production characterizes several vascular diseases. This study examined the effect of triglyceride on NO production induced by endothelin-3 (ET-3) in cultured human umbilical vein endothelial cells. Triglyceride-rich human plasma obtained after a high-carbohydrate diet with white wine was used in an ex vivo study. The plasma triglyceride fraction was found to consist of large amounts of palmitic and oleic acids detected by gas-liquid chromatography. Therefore, the effect of synthetic tripalmitin and triolein emulsion on NO production was also examined. ET-3 stimulated NO and guanosine 3',5'-cyclic monophosphate production and increased cytosolic Ca2+ levels in the endothelial cells (ECs). After incubation of the ECs with the triglyceride-rich plasma for 2 h, these responses to ET-3 were ameliorated in a triglyceride concentration-dependent manner (50-200 mg/dl). A synthesized emulsion of tripalmitin (100 mg/dl) and triolein (100 mg/dl) also blunted the responses to ET-3. Neither endothelial constitutive NO synthase mRNA expression nor its protein level was affected by treatment with triglycerides. These results suggest that triglyceride suppresses ET-3-induced NO synthesis in human ECs by inhibiting cytosolic Ca2+ elevation.

  8. The mycotoxin definition reconsidered towards fungal cyclic depsipeptides.

    Science.gov (United States)

    Taevernier, Lien; Wynendaele, Evelien; De Vreese, Leen; Burvenich, Christian; De Spiegeleer, Bart

    2016-04-01

    Currently, next to the major classes, cyclic depsipeptides beauvericin and enniatins are also positioned as mycotoxins. However, as there are hundreds more fungal cyclic depsipeptides already identified, should these not be considered as mycotoxins as well? The current status of the mycotoxin definition revealed a lack of consistency, leading to confusion about what compounds should be called mycotoxins. Because this is of pivotal importance in risk assessment prioritization, a clear and quantitatively expressed mycotoxin definition is proposed, based on data of widely accepted mycotoxins. Finally, this definition is applied to a set of fungal cyclic depsipeptides, revealing that some of these should indeed be considered as mycotoxins.

  9. Constacyclic and cyclic codes over finite chain rings

    Institute of Scientific and Technical Information of China (English)

    QIAN Jian-fa; MA Wen-ping

    2009-01-01

    The problem of Gray image of constacyclic code over finite chain ring is studied. A Gray map between codes over a finite chain ring and a finite field is defined. The Gray image of a linear constacyclic code over the finite chain ring is proved to be a distance invariant quasi-cyclic code over the finite field. It is shown that every code over the finite field, which is the Gray image of a cyclic code over the finite chain ring, is equivalent to a quasi-cyclic code.

  10. Laterally cyclic loading of monopile in dense sand

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Hededal, Ole; Svensson, M.

    2011-01-01

    the loading conditions. In these tests the load conditions are controlled by two load characteristics, one controlling the level of the cyclic loading and one controlling the characteristic of the cyclic loading. The centrifuge tests were performed in dense dry sand on a pile with prototype dimensions......In order to investigate the response from laterally cyclic loading of monopiles a large centrifuge tests series is ongoing at the Technical University of Denmark (DTU). This paper will present some of the tests carried out with a focus on the influence of accumulation of rotation when changing...

  11. Centrifuge modelling of a laterally cyclic loaded pile

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  12. Electrochemical Reduction of Oxygen and Nitric oxide at low Temperature on La1-xSrxCr0.97V0.03O3-δ Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2013-01-01

    Five La1-xSrxCr0.97V0.03O3-δ (x = 0, 0.05, 0.15, 0.25, 0.35) perovskites were synthesized and characterized by powder XRD and cyclic voltammetry on cone-shaped electrodes in 10% oxygen in argon or 1% nitric oxide in argon at 200, 300 and 400°C. It was shown that the activation energy...

  13. Nitric oxide production and nitric oxide synthase immunoreactivity in Naegleria fowleri.

    Science.gov (United States)

    Rojas-Hernández, Saúl; Rodríguez-Monroy, Marco A; Moreno-Fierros, Leticia; Jarillo-Luna, Adriana; Carrasco-Yepez, Marisela; Miliar-García, Angel; Campos-Rodríguez, Rafael

    2007-07-01

    Free-living ameba Naegleria fowleri produces an acute and fatal infectious disease called primary amebic meningoencephalitis (PAM), whose pathophysiological mechanism is largely unknown. The aim of this study was to investigate the role of nitric oxide (NO) in PAM. Although NO has a cytotoxic effect on various parasites, it is produced by others as part of the pathology, as is the case with Entamoeba histolytica. To test for the production of NO, we analyzed whether antibodies against mammalian NO synthase isoforms (neuronal, inducible, and endothelial) presented immunoreactivity to N. fowleri proteins. We found that the trophozoites produced NO in vitro. The Western blot results, which showed N. fowleri trophozoites, contained proteins that share epitopes with the three described mammalian NOS, but have relative molecular weights different than those described in the literature, suggesting that N. fowleri may contain undescribed NOS isoforms. Moreover, we found that trophozoites reacted to the NOS2 antibody, in amebic cultures as well as in the mouse brain infected with N. fowleri, suggesting that nitric oxide may participate in the pathogenesis of PAM. Further research aimed at determining whether N. fowleri contains active novel NOS isoforms could lead to the design of new therapies against this parasite.

  14. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  15. AMP-activated protein kinase (AMPK) regulates the insulin-induced activation of the nitric oxide synthase in human platelets.

    Science.gov (United States)

    Fleming, Ingrid; Schulz, Christian; Fichtlscherer, Birgit; Kemp, Bruce E; Fisslthaler, Beate; Busse, Rudi

    2003-11-01

    Little is known about the signaling cascades that eventually regulate the activity of the endothelial nitric oxide synthase (eNOS) in platelets. Here, we investigated the effects of insulin on the phosphorylation and activation of eNOS in washed human platelets and in endothelial cells. Insulin activated the protein kinase Akt in cultured endothelial cells and increased the phosphorylation of eNOS on Ser(1177) but failed to increase endothelial cyclic GMP levels or to elicit the relaxation of endothelium-intact porcine coronary arteries. In platelets, insulin also elicited the activation of Akt as well as the phosphorylation of eNOS and initiated NO production which was associated with increased cyclic GMP levels and the inhibition of thrombin-induced aggregation. The insulin-induced inhibition of aggregation was accompanied by a decreased Ca(2+) response to thrombin and was also prevented by N(omega) nitro-L-arginine. In platelets, but not in endothelial cells, insulin induced the activation of the AMP-activated protein kinase (AMPK), a metabolic stress-sensing kinase which was sensitive to the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin and the AMPK inhibitor iodotubercidin. Moreover, the insulin-mediated inhibition of thrombin-induced aggregation was prevented by iodotubercidin. Insulin-independent activation of the AMPK using 5-aminoimidazole-4-carboxamide ribonucleoside, increased platelet eNOS phosphorylation, increased cyclic GMP levels and attenuated platelet aggregation. These results highlight the differences in the signal transduction cascade activated by insulin in endothelial cells and platelets, and demonstrate that insulin stimulates the formation of NO in human platelets, in the absence of an increase in Ca(2+), by acti-vating PI3-K and AMPK which phosphorylates eNOS on Ser(1177).

  16. Transport of nitric oxide by perfluorocarbon emulsion.

    Science.gov (United States)

    Ortiz, Daniel; Cabrales, Pedro; Briceño, Juan C

    2013-01-01

    Perfluorocarbon (PFC) emulsions can transport and release various gases based on concentration gradients. The objective of this study was to determine the possibility of carrying and delivering exogenous nitric oxide (NO) into the circulation by simply loading PFC emulsion with NO prior infusion. PFC was equilibrated with room air (PFC) or 300 ppm NO (PFC-NO) at atmospheric pressure. Isotonic saline solution was used as a volume control (Saline). PFC and PFC-NO were infused at a dose of 3.5 mL/kg in the hamster window chamber model. Blood chemistry, and systemic and microvascular hemodynamic response were measured. Infusion of PFC preloaded with NO reduced blood pressure, induced microvascular vasodilation and increased capillary perfusion; although these changes lasted less than 30 min post infusion. On the other hand, infusion of PFC (without NO) produced vasoconstriction; however, the vasoconstriction was followed by vasodilatation at 30 min post infusion. Plasma nitrite and nitrate increased 15 min after infusion of NO preloaded PFC compared with PFC, 60 min after infusion nitrite and nitrate were not different, and 90 min after infusion plasma S-nitrosothiols increased in both groups. Infusion of NO preloaded PFC resulted in acute vascular relaxation, where as infusion of PFC (without NO) produced vasoconstriction, potentially due to NO sequestration by the PFC micelles. The late effects of PFC infusion are due to NO redistribution and plasma S-nitrosothiols. Gas solubility in PFC can provide a tool to modulate plasma vasoactive NO forms availability and improve microcirculatory function and promote increased blood flow.

  17. Nitric oxide in adaptation to altitude.

    Science.gov (United States)

    Beall, Cynthia M; Laskowski, Daniel; Erzurum, Serpil C

    2012-04-01

    This review summarizes published information on the levels of nitric oxide gas (NO) in the lungs and NO-derived liquid-phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500 m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24-48 h with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma, and/or red blood cells fell within 2h, but then returned toward baseline or slightly higher by 48 h and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than those of their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma, and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell-associated nitrogen oxides were more than 200 times higher. Other highland populations had generally higher levels although not to the degree shown by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction, although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors' and the Tibetans' high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions, and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function under hypoxic

  18. Anticonvulsant drugs, oxidative stress and nitric oxide.

    Science.gov (United States)

    Vega Rasgado, L A; Ceballos Reyes, G M; Vega-Diaz, M F

    2011-01-01

    Nitric Oxide (NO) is thought to play a fundamental role in the genesis and the spreading of epileptiform hyperactivity, although its function is unclear and controversial. As a free radical, NO may cause oxidative stress, which is emerging as an important mechanism in the etiology of seizure-induced neuronal death. Here we investigated the role of NO in seizure mechanisms through oxidative stress generation by studying the effect of anticonvulsant drugs such as amino oxyacetic acid (AAOA), valproate (VALP), diazepam (DIAZ) and gabapentin (GBPTNA) on oxidative stress in the brain, estimated as free carbonyls by the method of Dalle and Rossi, and by measuring NO by the indirect method based on the Griess reaction. Results show that, except for AAOA and VALP, anticonvulsants did not significantly affect or decreased free carbonyls, but reversed the oxidative stress produced by pentylenetetrazole (PTZ) induced convulsions. Anticonvulsants except AAOA diminished NO levels and with the exception of VALP, counteracted the increase in NO generated by PTZ. Anticonvulsants decreased oxidative stress and NO especially in hippocampus (HI) and cortex (CX), and reversed PTZ effects on both parameters. PTZ diminished NO in HI, which could be explained since PTZ caused an increase on endothelial NO synthase but a decrease in neuronal NOS expression in this brain area. Since the drugs studied are modulating GABA levels, our results suggest that seizures generated by alterations in GABAergic transmission produce oxidative stress caused by NO, which can be reversed by anticonvulsants. The effects described differ among the brain regions studied and the NO synthase isoform affected.

  19. Nitric oxide scavenging by red cell microparticles.

    Science.gov (United States)

    Liu, Chen; Zhao, Weixin; Christ, George J; Gladwin, Mark T; Kim-Shapiro, Daniel B

    2013-12-01

    Red cell microparticles form during the storage of red blood cells and in diseases associated with red cell breakdown and asplenia, including hemolytic anemias such as sickle cell disease. These small phospholipid vesicles that are derived from red blood cells have been implicated in the pathogenesis of transfusion of aged stored blood and hemolytic diseases, via activation of the hemostatic system and effects on nitric oxide (NO) bioavailability. Red cell microparticles react with the important signaling molecule NO almost as fast as cell-free hemoglobin, about 1000 times faster than red-cell-encapsulated hemoglobin. The degree to which this fast reaction with NO by red cell microparticles influences NO bioavailability depends on several factors that are explored here. In the context of stored blood preserved in ADSOL, we find that both cell-free hemoglobin and red cell microparticles increase as a function of duration of storage, and the proportion of extra erythrocytic hemoglobin in the red cell microparticle fraction is about 20% throughout storage. Normalized by hemoglobin concentration, the NO-scavenging ability of cell-free hemoglobin is slightly higher than that of red cell microparticles as determined by a chemiluminescence NO-scavenging assay. Computational simulations show that the degree to which red cell microparticles scavenge NO will depend substantially on whether they enter the cell-free zone next to the endothelial cells. Single-microvessel myography experiments performed under laminar flow conditions demonstrate that microparticles significantly enter the cell-free zone and inhibit acetylcholine, endothelial-dependent, and NO-dependent vasodilation. Taken together, these data suggest that as little as 5 μM hemoglobin in red cell microparticles, an amount formed after the infusion of one unit of aged stored packed red blood cells, has the potential to reduce NO bioavailability and impair endothelial-dependent vasodilation.

  20. Synthesis and Catalytic Activity of Two New Cyclic Tetraaza Ligands

    Directory of Open Access Journals (Sweden)

    Burkhard König

    2003-05-01

    Full Text Available Two new chiral cyclic tetraaza ligands were synthesized and characterized. Their catalytic activity was tested in the asymmetric addition of diethylzinc to benzaldehyde. The expected secondary alcohol was obtained in moderate yields, but with very low enantioselectivity.

  1. Cyclical mastalgia: Prevalence and associated determinants in Hamadan City, Iran

    Directory of Open Access Journals (Sweden)

    Fatemeh Shobeiri

    2016-03-01

    Conclusions: Most of women with breast discomfort suffered cyclical mastalgia which severity can be determined by advanced age, age of marriage, history of abortion and history of premenstrual syndrome, but inversely by oral contraceptive use and exercise activity.

  2. A constitutive model for unsaturated cemented soils under cyclic loading

    CERN Document Server

    Yang, C; Pereira, Jean-Michel; Huang, M S

    2008-01-01

    On the basis of plastic bounding surface model, the damage theory for structured soils and unsaturated soil mechanics, an elastoplastic model for unsaturated loessic soils under cyclic loading has been elaborated. Firstly, the description of bond degradation in a damage framework is given, linking the damage of soil's structure to the accumulated strain. The Barcelona Basic Model (BBM) was considered for the suction effects. The elastoplastic model is then integrated into a bounding surface plasticity framework in order to model strain accumulation along cyclic loading, even under small stress levels. The validation of the proposed model is conducted by comparing its predictions with the experimental results from multi-level cyclic triaxial tests performed on a natural loess sampled beside the Northern French railway for high speed train and about 140 km far from Paris. The comparisons show the capabilities of the model to describe the behaviour of unsaturated cemented soils under cyclic loading.

  3. A Novel Cyclic Catalytic Reformer for Hydrocarbon Fuels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses development of a compact reformer system based on a cyclic partial oxidation (POx)...

  4. Association of Marijuana Use and Cyclic Vomiting Syndrome

    Directory of Open Access Journals (Sweden)

    Mithun B. Pattathan

    2012-06-01

    Full Text Available Cannabis use has become one of the most commonly abused drugs in the world. It is estimated that each year 2.6 million individuals in the USA become new users and most are younger than 19 years of age. Reports describe marijuana use as high as 40–50% in male Cyclic Vomiting Syndrome patients. It is this interest in cannabis in the World, coupled with recognition of a cyclic vomiting illness associated with its chronic use that beckons a review of the most current articles, as well as a contribution from our own experiences in this area. The similarities we have demonstrated for both cannibinoid hyperemesis syndrome and cyclic vomiting make the case that cannibinoid hyperemesis syndrome is a subset of patients who have the diagnoses of cyclic vomiting syndrome and the role of marijuana should always be considered in the diagnosis of CVS, particularly in males.

  5. Resistance to cyclic loading of teeth restored with posts

    DEFF Research Database (Denmark)

    Sahafi, A; Peutzfeldt, A; Ravnholt, G

    2005-01-01

    This in vitro study evaluated the effect of presence of post, presence of core, and of shape, type, and surface treatment of posts on resistance to cyclic loading of crowned human teeth. For all teeth, crowns designed without ferrule were cast in sterling silver and luted with resin cement (Panavia...... F). Each tooth underwent cyclic loading of 600 N at two loads per second until failure. Teeth that had only been crowned showed significantly higher resistance to cyclic loading than teeth with cores or with post and cores. No significant differences were found between teeth restored with cores only...... or with post and cores, irrespective of surface-treatment of the posts. Teeth restored with parallel-sided cast post (ParaPost XP) and cores showed significantly higher resistance to cyclic loading than teeth with either tapered cast posts or untreated prefabricated posts of titanium alloy (ParaPost XH...

  6. Cyclic Family Symmetry and Lepton Hierarchy in Supersymmetry

    OpenAIRE

    Du, Dongsheng; Chun LIU

    1995-01-01

    A cyclic symmetry among the left-handed doublets of the three families is proposed. This symmetry can naturally result in a realistic hierarchical pattern of the fermion masses within the framework of supersymmetry with nonvanishing sneutrino vacuum expectation values.

  7. Cyclic Voltammetric Responses of Nitrate Reductase on Chemical Modified Electrodes

    Institute of Scientific and Technical Information of China (English)

    YaRuSONG; HuiBoSHAO; 等

    2002-01-01

    Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide cast on the pyrolytic graphite electrode was examined. NR on chemical modified electrode showed electrochemical cyclic voltammetric responses in phosphate buffers.

  8. Cyclical Cohabitation Among Unmarried Parents in Fragile Families.

    Science.gov (United States)

    Nepomnyaschy, Lenna; Teitler, Julien

    2013-10-01

    Building on past research suggesting that cohabitation is an ambiguous family form, the authors examined an understudied residential pattern among unmarried parents: cyclical cohabitation, in which parents have multiple cohabitation spells with each other. Using 9 years of panel data from the Fragile Families and Child Wellbeing Study (N = 2,084), they found that 10% of all parents with nonmarital births, and nearly a quarter of those living together when the child is 9 years old, are cyclical cohabitors. Cyclically cohabiting mothers reported more material hardships than mothers in most other relationship patterns but also reported more father involvement with children. On all measures of child well-being, except grade retention, children of cyclically cohabiting parents fared no worse than children of stably cohabiting biological parents and did not differ significantly from any other group.

  9. The antimycin A-sensitive pathway of cyclic electron flow

    DEFF Research Database (Denmark)

    Labs, Mathias; Rühle, Thilo; Leister, Dario Michael

    2016-01-01

    severe effects on plant growth. One of the two pathways mediating cyclic electron flow can be inhibited by antimycin A, a chemical that has also widely been used to characterize the mitochondrial respiratory chain. For the characterization of cyclic electron flow, antimycin A has been used since 1963......Cyclic electron flow has puzzled and divided the field of photosynthesis researchers for decades. This mainly concerns the proportion of its overall contribution to photosynthesis, as well as its components and molecular mechanism. Yet, it is irrefutable that the absence of cyclic electron flow has......, when ferredoxin was found to be the electron donor of the pathway. In 2013, antimycin A was used to identify the PGRL1/PGR5 complex as the ferredoxin:plastoquinone reductase completing the last puzzle piece of this pathway. The controversy has not ended, and here, we review the history of research...

  10. Cyclical Cushing's syndrome due to an atypical thymic carcinoid

    NARCIS (Netherlands)

    Meinardi, [No Value; van den Berg, G; Wolffenbuttel, BHR; Kema, IP; Dullaart, RPF

    A 43-year-old man presented with fluctuating symptoms of weight gain, shortness of breath, pretibial oedema, associated with anxiety and memory disturbances. Laboratory investigation revealed an adrenocorticotropin (ACTH)-dependent cyclical Cushing's syndrome characterised by remarkable variations

  11. Cyclic Redundancy Checking (CRC) Accelerator for Embedded Processor Datapaths

    National Research Council Canada - National Science Library

    Abdul Rehman Buzdar; Liguo Sun; Rao Kashif; Muhammad Waqar Azhar; Muhammad Imran Khan

    2017-01-01

    We present the integration of a multimode Cyclic Redundancy Checking (CRC) accelerator unit with an embedded processor datapath to enhance the processor performance in terms of execution time and energy efficiency...

  12. Gauss Sum of Index 4: (2) Non-cyclic Case

    Institute of Scientific and Technical Information of China (English)

    Jing YANG; Shi Xin LUO; Ke Qin FENG

    2006-01-01

    Assume that m≥2,p is a prime number,(m,p(p-1))=1,-1(∈)(∈)((Z)/m(Z))* and [((z)/m(Z)*:]=4.In this paper,we calculate the value of Gauss sum G(χ)=∑x(F)*qχ(x)ζTp(x) over (F)q,where q=pf,(f)=(ψ)(m)/4,χ is a multiplicative character of (F)q and T is the trace map from (F)q to (F)p.Under our assumptions,C(χ) belongs to the decomposition field K of p in (Q)(ζm) and K is an imaginary quartic abelian number field.When the Galois group Gal(K/(Q)) is cyclic,we have studied this cyclic case in another paper:"Gauss sums of index four:(1) cyclic case" (accepted by Acta Mathematica Sinica,2003).In this paper we deal with the non-cyclic case.

  13. Properties of Surface Cyclic Oligomers Present on Polyester Fiber

    Institute of Scientific and Technical Information of China (English)

    郑敏; 宋心远

    2003-01-01

    The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on properties of the cyclic oligomers on the surface of polyester fiber are studied. The components of surface oligomers are analyzed through Thin-Layer Chromatograph. The result shows that: all of the treatments, especially solvent vapor treatment, can significantly increase the content of surface cyclic oligomers. The content of cyclic trimer is increased more considerably than other oligomers. Moreover, the morphology and the distribution of surface cyclic oligomers are also different from different treatments: Dry heat and wet heat cause larger polygonal solids distributed evenly on the surface of fiber; solvent vapor makes fiber surface exhibit irregular rodlike crystal shapes randomly; ultrasonic treatment induces some obscure and smaller deposits on the surface of fiber.

  14. The Cyclical Relationship Approach in Teaching Basic Accounting Principles.

    Science.gov (United States)

    Golen, Steven

    1981-01-01

    Shows how teachers can provide a more meaningful presentation of various accounting principles by illustrating them through a cyclical relationship approach. Thus, the students see the entire accounting relationship as a result of doing business. (CT)

  15. Cyclic viscoelasticity and viscoplasticity of polypropylene/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Hog Lejre, Anne-Lise

    2012-01-01

    Observations are reported in tensile relaxation tests under stretching and retraction on poly-propylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of hybrid nanocomposites. Adjustable parameters...

  16. Safety Discrete Event Models for Holonic Cyclic Manufacturing Systems

    Science.gov (United States)

    Ciufudean, Calin; Filote, Constantin

    In this paper the expression “holonic cyclic manufacturing systems” refers to complex assembly/disassembly systems or fork/join systems, kanban systems, and in general, to any discrete event system that transforms raw material and/or components into products. Such a system is said to be cyclic if it provides the same sequence of products indefinitely. This paper considers the scheduling of holonic cyclic manufacturing systems and describes a new approach using Petri nets formalism. We propose an approach to frame the optimum schedule of holonic cyclic manufacturing systems in order to maximize the throughput while minimize the work in process. We also propose an algorithm to verify the optimum schedule.

  17. Coping with cyclic oxygen availability: evolutionary aspects.

    Science.gov (United States)

    Flück, Martin; Webster, Keith A; Graham, Jeffrey; Giomi, Folco; Gerlach, Frank; Schmitz, Anke

    2007-10-01

    Both the gradual rise in atmospheric oxygen over the Proterozoic Eon as well as episodic fluctuations in oxygen over several million-year time spans during the Phanerozoic Era, have arguably exerted strong selective forces on cellular and organismic respiratory specialization and evolution. The rise in atmospheric oxygen, some 2 billion years after the origin of life, dramatically altered cell biology and set the stage for the appearance of multicelluar life forms in the Vendian (Ediacaran) Period of the Neoproterozoic Era. Over much of the Paleozoic, the level of oxygen in the atmosphere was near the present atmospheric level (21%). In the Late Paleozoic, however, there were extended times during which the level of atmospheric oxygen was either markedly lower or markedly higher than 21%. That these Paleozoic shifts in atmospheric oxygen affected the biota is suggested by the correlations between: (1) Reduced oxygen and the occurrences of extinctions, a lowered biodiversity and shifts in phyletic succession, and (2) During hyperoxia, the corresponding occurrence of phenomena such as arthropod gigantism, the origin of insect flight, and the evolution of vertebrate terrestriality. Basic similarities in features of adaptation to hyopoxia, manifest in living organisms at levels ranging from genetic and cellular to physiological and behavioral, suggest the common and early origin of a suite of adaptive mechanisms responsive to fluctuations in ambient oxygen. Comparative integrative approaches addressing the molecular bases of phenotypic adjustments to cyclic oxygen fluctuation provide broad insight into the incremental steps leading to the early evolution of homeostatic respiratory mechanisms and to the specialization of organismic respiratory function.

  18. Cyclic Benzimidazole Derivatives and Their Antitumor Activity

    Directory of Open Access Journals (Sweden)

    Karminski-Zamola, G.

    2008-06-01

    Full Text Available Over the past years benzimidazole derivatives are one of the most extensively studied classes of heterocyclic compounds, and have received much attention from synthetic organic as well as medicinal chemists, because of their well known biological activities and their applications in several areas as materials in electronics, in electrochemistry as anticorrosive agents, as polymers or optical materials and fluorescent tags in DNA sequencing. The structure of vitamin B12, as an example, contains a benzimidazole group. Compounds containing benzimidazole nuclei show anticancer, antineoplastic, antiinfective, antibacterial, antifungal and many others activities. Due to the structural similarity of benzimidazole nuclei with some naturally occurring compounds such as purine, they can easily interact with biomolecules of the living systems. The introduction of an additional substituent on the benzimidazole nuclei has been increasing attention in the expectation that such changes could potentially affect the interaction of the molecules with biological targets. Fused cyclic benzimidazole derivatives, as benzimidazo[1,2-a]quinolines,benzimidazo[1,2-c]quinazolines, benzimidazo[2,1-b]isoquinolines and many others, have also interesting biological activities and most of them are very good anticancer agents.DNA is the molecular target of many anticancer drugs in clinical use and development. Compounds which can bind to DNA with intercalative or non-intercalative mechanism play a major role in biological processes such as gene transcription or DNA replication. Benzoannulated benzimidazole analogues contain a planar chromophore and have the ability to become inserted between adjacent base pairs of DNA double helix. Intercalators are recognized as one of the most important classes of anticancer agents. So an understanding of the drug-DNA interactions is a promising approach to developing novel reagents and plays a key role in pharmacology today.

  19. Deformation localization and cyclic strength in polycrystalline molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Sidorov, O.T.; Rakshin, A.F.; Fenyuk, M.I.

    1983-06-01

    Conditions of deformation localization and its interrelation with cyclic strength in polycrystalline molybdenum were investigated. A fatigue failure of polycrystalline molybdenum after rolling and in an embrittled state reached by recrystallization annealing under cyclic bending at room temperature takes place under nonuniform distribution of microplastic strain resulting in a temperature rise in separate sections of more than 314 K. More intensive structural changes take place in molybdenum after rolling than in recrystallized state.

  20. Defect agglomeration in ferroelectric ceramics under cyclic electric field

    Institute of Scientific and Technical Information of China (English)

    GENG LiMing; YANG Wei

    2008-01-01

    The agglomeration of point defects in ferroelectric ceramics could be driven by repeated domain switching under cyclic electric field. The evolution equation of pore concentration under cyclic electric field is derived, with the help of a relation between the pore concentration and the extent of pore agglomeration. The results of the simulation agree quantitatively with the experimental data. An integrated framework about the mechanisms of electrically induced fatigue is proposed, which links the mechanisms at different scales.

  1. Cyclical Long-term Unemployment, Skill Loss, and Monetary Policy

    OpenAIRE

    2012-01-01

    Movements in long-term unemployment (LTU) exhibit a substantial cyclical component. I develop a business cycle model featuring labor market frictions and skill loss during unemployment to capture various stylized facts about the cyclical behavior of long-term unemployment. I find that the skill loss mechanism helps reproduce negative duration dependence, high persistence in unemployment and output, volatility patterns across macroeconomic variables and the behavior of the incidence of LTU aro...

  2. Paediatric cyclical Cushing's disease due to corticotroph cell hyperplasia.

    LENUS (Irish Health Repository)

    Noctor, E

    2015-06-01

    Cushing\\'s disease is very rare in the paediatric population. Although uncommon, corticotroph hyperplasia causing Cushing\\'s syndrome has been described in the adult population, but appears to be extremely rare in children. Likewise, cyclical cortisol hypersecretion, while accounting for 15 % of adult cases of Cushing\\'s disease, has only rarely been described in the paediatric population. Here, we describe a very rare case of a 13-year old boy with cyclical cortisol hypersecretion secondary to corticotroph cell hyperplasia.

  3. Recovery of Compressively Sampled Sparse Signals using Cyclic Matching Pursuit

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Christensen, Mads Græsbøll; Gribonval, Rémi

    We empirically show how applying a pure greedy algorithm cyclically can recover compressively sampled sparse signals as well as other more computationally complex approaches, such as orthogonal greedy algorithms, iterative thresholding, and $\\ell_1$-minimization.......We empirically show how applying a pure greedy algorithm cyclically can recover compressively sampled sparse signals as well as other more computationally complex approaches, such as orthogonal greedy algorithms, iterative thresholding, and $\\ell_1$-minimization....

  4. Dynamic Cyclic Thiodepsipeptide Libraries from Thiol-Thioester Exchange

    Science.gov (United States)

    2010-04-01

    the reaction dynamics are discussed. Cyclic peptides have been described as “privileged structures” for drug design because so many natural and...inhibitors, which hold promise for treatment of cancer.4 As drug scaffolds, cyclic peptides are advantageous because they mimic native protein structure...but instead an influence of chirality on the accessibility of the thioester or thiol. We also investigated the effect of positively charged amino

  5. CYCLIC CODES OVER THE RING Zp2 OF LENGTH pe

    Institute of Scientific and Technical Information of China (English)

    Shi Minjia; Zhu Shixin

    2008-01-01

    The study of cyclic codes over rings has generated a lot of public interest. In this paper,we study cyclic codes and their dual codes over the ring Zp2 of length pe,and find a set of generators for these codes. The ranks and minimal generator sets of these codes are studied as well,which play an important role in decoding and determining the distance distribution of codes.

  6. Microgravity changes in heart structure and cyclic-AMP metabolism

    Science.gov (United States)

    Philpott, D. E.; Fine, A.; Kato, K.; Egnor, R.; Cheng, L.

    1985-01-01

    The effects of microgravity on cardiac ultrastructure and cyclic AMP metabolism in tissues of rats flown on Spacelab 3 are reported. Light and electron microscope studies of cell structure, measurements of low and high Km phosphodiesterase activity, cyclic AMP-dependent protein kinase activity, and regulatory subunit compartmentation show significant deviations in flight animals when compared to ground controls. The results indicate that some changes have occurred in cellular responses associated with catecholamine receptor interactions and intracellular signal processing.

  7. Towards an incremental maintenance of cyclic association rules

    CERN Document Server

    Ahmed, Eya ben

    2010-01-01

    Recently, the cyclic association rules have been introduced in order to discover rules from items characterized by their regular variation over time. In real life situations, temporal databases are often appended or updated. Rescanning the whole database every time is highly expensive while existing incremental mining techniques can efficiently solve such a problem. In this paper, we propose an incremental algorithm for cyclic association rules maintenance. The carried out experiments of our proposal stress on its efficiency and performance.

  8. Distributed consensus on minimum time rendezvous via cyclic alternating projection

    OpenAIRE

    Hu, Chunhe; Chen, Zongji

    2014-01-01

    In this paper, we propose a distributed algorithm to solve planar minimum time multi-vehicle rendezvous problem with non-identical velocity constraints on cyclic digraph (topology). Motivated by the cyclic alternating projection method that can compute a point's projection on the intersection of some convex sets, we transform the minimum time rendezvous problem into finding the distance between the position plane and the intersection of several second-order cones in position-time space. The d...

  9. Asymmetric synthesis of gem-diaryl substituted cyclic sulfamidates and sulfamides by rhodium-catalyzed arylation of cyclic ketimines.

    Science.gov (United States)

    Nishimura, Takahiro; Ebe, Yusuke; Fujimoto, Hiroto; Hayashi, Tamio

    2013-06-18

    Asymmetric addition of arylboronates to aryl-substituted cyclic ketimines proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of sulfamidates and sulfamides with high enantioselectivity (up to 99% ee).

  10. Effect of cyclic torsional preloading on cyclic fatigue resistance of ProTaper Next and Mtwo nickel–titanium instruments

    Directory of Open Access Journals (Sweden)

    Eugenio Pedullà

    2015-06-01

    Conclusions: Torsional preloads reduced the cyclic fatigue resistance of M-wire and conventional (as ProTaper Next and Mtwo NiTi rotary instruments except for Mtwo with 25% or 50% of torsional preloading.

  11. Nitric oxide as a carcinogen. Analysis by yeast functional assay of inactivating p53 mutations induced by nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Jun-Ichi; Tada, Mitsuhiro; Sawamura, Yutaka; Shinohe, Yumiko; Abe, Hiroshi [Laboratory for Molecular Brain Research, Department of Neurosurgery, Hokkaido University School of Medicine, Sapporo (Japan); Iggo, Richard D. [Oncogene group, Swiss Institute for Experimental Cancer Research ISREC, Epalinges (Switzerland)

    1997-10-06

    We have used a yeast p53 functional assay to study induction of mutations in the p53 tumor suppressor gene by nitric oxide and cytosine methylation. The yeast assay identifies only biologically important p53 mutations. p53 cDNA was treated with the nitric oxide donor sydnonimine, PCR-amplified and transfected into yeast. Sydnonimine produced a significant, dose-dependent increase in C:G->A:T transversions. Many important p53 mutational hotspots are postulated to arise by deamination of methylCpG in tumors. We therefore examined nitric oxide induction of mutations in p53 cDNA methylated by PCR-mediated substitution of 5-methylcytosine for cytosine or by treatment with the SssI CpG methylase. Both methylation procedures increased the baseline mutation rate, and nitric oxide treatment produced a further increase in mutation yield. Sequence analysis showed that methylation alone led to C:G->T:A transitions, whereas nitric oxide treatment simply produced more C:G->A:T transversions. Thus the most important factor in C:G->T:A transition at CpG sites identified in this experimental system is cytosine methylation, consistent with spontaneous conversion of 5-methylcytosine to thymine by deamination

  12. Pain modulation by nitric oxide in the spinal cord.

    Directory of Open Access Journals (Sweden)

    Marco Aurelio M Freire

    2009-09-01

    Full Text Available Nitric oxide (NO is a versatile messenger molecule first associated with endothelial relaxing effects. In the central nervous system (CNS, NO synthesis is primarily triggered by activation of N-methyl-D-aspartate (NMDA receptors and has a Janus face, with both beneficial and harmful properties, depending on concentration and the identity of its synthetic enzyme isoform. There are three isoforms of the NO synthesizing enzyme nitric oxide synthase (NOS: neuronal (nNOS, endothelial (eNOS, and inducible nitric oxide synthase (iNOS, each one involved with specific events in the brain. In CNS, nNOS is involved with modulation of synaptic transmission through long-term potentiation in several regions, including nociceptive circuits in the spinal cord. Here, we review the role played by NO on central pain sensitization.

  13. A nitric oxide donor (nitroglycerin) triggers genuine migraine attacks

    DEFF Research Database (Denmark)

    Thomsen, L L; Kruuse, C; Iversen, Helle Klingenberg

    1994-01-01

    Supersensitivity to induction of headache and arterial dilatation by a donor of nitric oxide (nitroglycerin) has recently been demonstrated in migraine sufferers. The aims of the present study were to examine whether the nitric oxide donor nitroglycerin may induce a typical migraine attack.......03). The time pattern of headache and estimated middle cerebral artery dilatation corresponded well. The study therefore demonstrates that activation of the nitric oxide cGMP pathway may cause typical migraine attacks......., to exclude placebo-related effects and to describe the relation between middle cerebral artery dilatation and provoked migraine. Nitroglycerin (0.5 μg/kg/min for 20 min) or placebo was infused into 12 migraine patients in a double-blind cross-over trial. Blood velocity in the middle cerebral artery...

  14. Photochemical reactions of neptunium in nitric acid solution containing photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Fukasawa, Tetsuo; Kawamura, Fumio (Hitachi Ltd., Ibaraki (Japan). Energy Research Lab.)

    1991-01-01

    Photochemical oxidation and reduction behaviors of neptunium were preliminarily investigated in 3 mol/l nitric acid solution. Nitric acid of 3 mol/l simulated the high level waste solution from a spent fuel reprocessing process. Concentrations of Np(V), Np(VI) and nitrous acid were determined with a photospectrometer, and solution potential with an electrode. Without additives, Np(VI) was reduced to Np(V) by nitrous acid which was photolytically generated from nitric acid. With a scavenger for nitrous acid, Np(V) was oxidized to extractable Np(VI) by a photolytically generated oxidizing reagent which were predicted by the solution potential measurement. The reduction rate was higher than the oxidation rate because of the larger quantity and higher reactivity of nitrous acid than an oxidizing reagent. Photocatalyst was proved to be effective for the oxidation of Np(V) to Np(VI). (author).

  15. Nitric oxide: an intermediate in nitrate reduction in Klebsiella pneumoniae

    Energy Technology Data Exchange (ETDEWEB)

    Al-Abdulla, J.M.; Aleem, M.I.H.

    1977-01-01

    When K. pneumoniae cells were grown anaerobically with nitrate as the final electron acceptor, there was a rapid reduction of nitrate to nitrite. The latter was further reduced to hydroxylamine and finally to ammonia. Nitrate, nitrite and nitric oxide, but not nitrous oxide, could accept electrons from the respiratory chain. During growth of the organism it was possible to trap nitric oxide with alkaline permanganate. The trapped gas represented only a small portion of the reduced electron acceptor. It would appear that a major portion of nitric oxide produced from nitrite reduction must be converted to an unknown nitrogenous intermediate with an oxidation state of +1 before its reduction to hydroxylamine. The possible nature of this elusive intermediate should be discussed.

  16. Nitric Oxide in Astrocyte-Neuron Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nianzhen [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Astrocytes, a subtype of glial cell, have recently been shown to exhibit Ca2+ elevations in response to neurotransmitters. A Ca2+ elevation can propagate to adjacent astrocytes as a Ca2+ wave, which allows an astrocyte to communicate with its neighbors. Additionally, glutamate can be released from astrocytes via a Ca2+-dependent mechanism, thus modulating neuronal activity and synaptic transmission. In this dissertation, the author investigated the roles of another endogenous signal, nitric oxide (NO), in astrocyte-neuron signaling. First the author tested if NO is generated during astrocytic Ca2+ signaling by imaging NO in purified murine cortical astrocyte cultures. Physiological concentrations of a natural messenger, ATP, caused a Ca2+-dependent NO production. To test the roles of NO in astrocytic Ca2+ signaling, the author applied NO to astrocyte cultures via addition of a NO donor, S-nitrosol-N-acetylpenicillamine (SNAP). NO induced an influx of external Ca2+, possibly through store-operated Ca2+ channels. The NO-induced Ca2+ signaling is cGMP-independent since 8-Br-cGMP, an agonistic analog of cGMP, did not induce a detectable Ca2+ change. The consequence of this NO-induced Ca2+ influx was assessed by simultaneously monitoring of cytosolic and internal store Ca2+ using fluorescent Ca2+ indicators x-rhod-1 and mag-fluo-4. Blockage of NO signaling with the NO scavenger PTIO significantly reduced the refilling percentage of internal stores following ATP-induced Ca2+ release, suggesting that NO modulates internal store refilling. Furthermore, locally photo-release of NO to a single astrocyte led to a Ca2+ elevation in the stimulated astrocyte and a subsequent Ca2+ wave to neighbors. Finally, the author tested the role of NO inglutamate-mediated astrocyte-neuron signaling by

  17. Nitric Oxide in Astrocyte-Neuron Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Nianzhen Li

    2002-06-27

    Astrocytes, a subtype of glial cell, have recently been shown to exhibit Ca{sup 2+} elevations in response to neurotransmitters. A Ca{sup 2+} elevation can propagate to adjacent astrocytes as a Ca{sup 2+} wave, which allows an astrocyte to communicate with its neighbors. Additionally, glutamate can be released from astrocytes via a Ca{sup 2+}-dependent mechanism, thus modulating neuronal activity and synaptic transmission. In this dissertation, the author investigated the roles of another endogenous signal, nitric oxide (NO), in astrocyte-neuron signaling. First the author tested if NO is generated during astrocytic Ca{sup 2+} signaling by imaging NO in purified murine cortical astrocyte cultures. Physiological concentrations of a natural messenger, ATP, caused a Ca{sup 2+}-dependent NO production. To test the roles of NO in astrocytic Ca{sup 2+} signaling, the author applied NO to astrocyte cultures via addition of a NO donor, S-nitrosol-N-acetylpenicillamine (SNAP). NO induced an influx of external Ca{sup 2+}, possibly through store-operated Ca{sup 2+} channels. The NO-induced Ca{sup 2+} signaling is cGMP-independent since 8-Br-cGMP, an agonistic analog of cGMP, did not induce a detectable Ca{sup 2+} change. The consequence of this NO-induced Ca{sup 2+} influx was assessed by simultaneously monitoring of cytosolic and internal store Ca{sup 2+} using fluorescent Ca{sup 2+} indicators x-rhod-1 and mag-fluo-4. Blockage of NO signaling with the NO scavenger PTIO significantly reduced the refilling percentage of internal stores following ATP-induced Ca{sup 2+} release, suggesting that NO modulates internal store refilling. Furthermore, locally photo-release of NO to a single astrocyte led to a Ca{sup 2+} elevation in the stimulated astrocyte and a subsequent Ca{sup 2+} wave to neighbors. Finally, the author tested the role of NO inglutamate-mediated astrocyte-neuron signaling by recording the astrocyte-evoked glutamate-dependent neuronal slow inward current (SIC

  18. Light activated nitric oxide releasing materials

    Science.gov (United States)

    Muizzi Casanas, Dayana Andreina

    The ability to control the location and dosage of biologically active molecules inside the human body can be critical to maximizing effective treatment of cardiovascular diseases like angina. The current standard of treatment relies on the metabolism of organonitrate drugs into nitric oxide (NO), which are not specific, and also show problems with densitization with long-term use. There is a need then to create a treatment method that gives targeted release of NO. Metal-nitrosyl (M-NO) complexes can be used for delivery of NO since the release of NO can be controlled with light. However, the NO-releasing drug must be activated with red light to ensure maximum penetration of light through tissue. However, the release of NO from M-NO complexes with red-light activation is a significant challenge since the energy required to break the metal-NO bond is usually larger than the energy provided by red light. The goal of this project was to create red- sensitive, NO-releasing materials based on Ru-salen-nitrosyl compounds. Our approach was to first modify Ru salen complexes to sensitize the photochemistry for release of NO after red light irradiation. Next, we pursued polymerization of the Ru-salen complexes. We report the synthesis and quantitative photochemical characterization of a series of ruthenium salen nitrosyl complexes. These complexes were modified by incorporating electron donating groups in the salen ligand structure at key locations to increase electron density on the Ru. Complexes with either an --OH or --OCH3 substituent showed an improvement in the quantum yield of release of NO upon blue light irradiation compared to the unmodified salen. These --OH and --OCH3 complexes were also sensitized for NO release after red light activation, however the red-sensitive complexes were unstable and showed ligand substitution on the order of minutes. The substituted complexes remained sensitive for NO release, but only after blue light irradiation. The Ru

  19. On the resolutions of cyclic Steiner triple systems with small parameters

    Directory of Open Access Journals (Sweden)

    Svetlana Topalova

    2016-09-01

    Full Text Available The paper presents useful invariants of resolutions of cyclic $STS(v$ with $v\\le 39$, namely of all resolutions of cyclic $STS(15$, $STS(21$ and $STS(27$, of the resolutions with nontrivial automorphisms of cyclic $STS(33$ and of resolutions with automorphisms of order $13$  of cyclic $STS(39$.

  20. Thyroid disorders and nitric oxide in cardiovascular adaptation to hypovolemia.

    Science.gov (United States)

    Ogonowski, Natalia; Piro, Giselle; Pessah, Déborah; Arreche, Noelia; Puchulu, Bernardita; Balaszczuk, Ana M; Fellet, Andrea L

    2016-08-01

    This study aimed to investigate whether nitric oxide participates in the cardiovascular function and haemodynamic adaptation to acute haemorrhage in animals with thyroid disorders. Sprague-Dawley rats aged 2months old treated with T3 (hyper, 20μg/100g body weight) or 0.02% methimazole (hypo, w/v) during 28days were pre-treated with N(G) nitro-l-arginine methyl ester (L-NAME) and submitted to 20% blood loss. Heart function was evaluated by echocardiography. Measurements of arterial blood pressure, heart rate, nitric oxide synthase activity and protein levels were performed. We found that hypo decreased fractional shortening and ejection fraction and increased left ventricle internal diameter. Hyper decreased ventricle diameter and no changes in cardiac contractility. Haemorrhage elicited a hypotension of similar magnitude within 10min. Then, this parameter was stabilized at about 30-40min and maintained until finalized, 120min. L-NAME rats showed that the immediate hypotension would be independent of nitric oxide. Nitric oxide synthase inhibition blunted the changes of heart rate induced by blood loss. Hyper and hypo had lower atrial enzyme activity associated with a decreased enzyme isoform in hypo. In ventricle, hyper and hypo had a higher enzyme activity, which was not correlated with changes in protein levels. Haemorrhage induced an increased heart nitric oxide production. We concluded that thyroid disorders were associated with hypertrophic remodelling which impacted differently on cardiac function and its adaptation to a hypovolemia. Hypovolemia triggered a nitric oxide synthase activation modulating the heart function to maintain haemodynamic homeostasis. This involvement depends on a specific enzyme isoform, cardiac chamber and thyroid state.