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Sample records for activity respiratory bursts

  1. Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst

    SciTech Connect

    Ahluwalia, Jatinder

    2008-10-31

    Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I{sub e}. In the present study, the effects of inhibitors of swell activated chloride channels on ROS production and on the swelling activated chloride conductance was investigated in activated human neutrophils. Tamoxifen (10 {mu}M), a specific inhibitor for swell activated chloride channels in neutrophils, completely inhibited both the PMA and FMLP stimulated respiratory burst. This inhibition of the neutrophil respiratory burst was not due to the blocking effect of tamoxifen on the swelling activated chloride conductance in these cells. These results demonstrate that a tamoxifen insensitive swell activated chloride channel has important significance during the neutrophil respiratory burst.

  2. Phagocyte respiratory burst activates macrophage erythropoietin signalling to promote acute inflammation resolution

    PubMed Central

    Luo, Bangwei; Wang, Jinsong; Liu, Zongwei; Shen, Zigang; Shi, Rongchen; Liu, Yu-Qi; Liu, Yu; Jiang, Man; Wu, Yuzhang; Zhang, Zhiren

    2016-01-01

    Inflammation resolution is an active process, the failure of which causes uncontrolled inflammation which underlies many chronic diseases. Therefore, endogenous pathways that regulate inflammation resolution are fundamental and of wide interest. Here, we demonstrate that phagocyte respiratory burst-induced hypoxia activates macrophage erythropoietin signalling to promote acute inflammation resolution. This signalling is activated following acute but not chronic inflammation. Pharmacological or genetical inhibition of the respiratory burst suppresses hypoxia and macrophage erythropoietin signalling. Macrophage-specific erythropoietin receptor-deficient mice and chronic granulomatous disease (CGD) mice, which lack the capacity for respiratory burst, display impaired inflammation resolution, and exogenous erythropoietin enhances this resolution in WT and CGD mice. Mechanistically, erythropoietin increases macrophage engulfment of apoptotic neutrophils via PPARγ, promotes macrophage removal of debris and enhances macrophage migration to draining lymph nodes. Together, our results provide evidences of an endogenous pathway that regulates inflammation resolution, with important implications for treating inflammatory conditions. PMID:27397585

  3. Respiratory burst oxidase of fertilization.

    PubMed Central

    Heinecke, J W; Shapiro, B M

    1989-01-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation of egg activation modulate the activity of the oxidase. Inhibitors were used to test the relevance of this oxidase to the respiratory burst of fertilization. Procaine, two phenothiazines, and N-ethylmaleimide (but not iodoacetamide) inhibited H2O2 production by the oxidase fraction and oxygen consumption by activated eggs. The ATP requirement suggested that protein kinase activity might regulate the respiratory burst of fertilization; consonant with this hypothesis, H-7 and staurosporine were inhibitory. The respiratory burst oxidase of fertilization is an NADPH:O2 oxidoreductase that appears to be regulated by a protein kinase; although it bears a remarkable resemblance to the neutrophil oxidase, unlike the latter it does not form O2- as its initial product. PMID:2537493

  4. ADP stimulates the respiratory burst without activation of ERK and AKT in rat alveolar macrophages.

    PubMed

    Gozal, E; Forman, H J; Torres, M

    2001-09-01

    Alveolar macrophages (AM) are the first line of defense against infection in the lungs. We previously showed that the production of superoxide and hydrogen peroxide, i.e., the respiratory burst, is stimulated by adenine nucleotides (ADP > ATP) in rat AM through signaling pathways involving calcium and protein kinase C. Here, we further show that ADP induces a rapid increase in the tyrosine phosphorylation of several proteins that was reduced by the tyrosine kinase inhibitor genistein, which also inhibited the respiratory burst. Interestingly, ADP did not trigger the activation of the mitogen-activated protein kinases ERK1 and ERK2, or that of protein kinase B/AKT, a downstream target of the phosphatidylinositol 3-kinase (PI3K) pathway. This is in contrast to another stimulus of the respiratory burst, zymosan-activated serum (ZAS), which activates both the ERK and PI3K pathways. Thus, this study demonstrates that the receptor for ADP in rat AM is not coupled to the ERK and AKT pathways and, that neither the ERK pathway nor AKT is essential to induce the activation of the NAPDH oxidase by ADP in rat AM while tyrosine kinases appeared to be required. The rate and amount of hydrogen peroxide released by the ADP-stimulated respiratory burst was similar to that produced by ZAS stimulation. The absence of ERK activation after ADP stimulation therefore suggests that hydrogen peroxide is not sufficient to activate the ERK pathway in rat AM. Nonetheless, as hydrogen peroxide was necessary for ERK activation by ZAS, this indicates that, in contrast to ADP, ZAS stimulates a pathway that is targeted by hydrogen peroxide and leads to ERK activation.

  5. Phagocytosis and Respiratory Burst Activity in Lumpsucker (Cyclopterus lumpus L.) Leucocytes Analysed by Flow Cytometry

    PubMed Central

    Haugland, Gyri T.; Jakobsen, Ragnhild Aakre; Vestvik, Nils; Ulven, Kristian; Stokka, Lene; Wergeland, Heidrun I.

    2012-01-01

    In the present study, we have isolated leucocytes from peripheral blood, head kidney and spleen from lumpsucker (Cyclopterus lumpus L.), and performed functional studies like phagocytosis and respiratory burst, as well as morphological and cytochemical analyses. Different leucocytes were identified, such as lymphocytes, monocytes/macrophages and polymorphonuclear cells with bean shaped or bilobed nuclei. In addition, cells with similar morphology as described for dendritic cells in trout were abundant among the isolated leucocytes. Flow cytometry was successfully used for measuring phagocytosis and respiratory burst activity. The phagocytic capacity and ability were very high, and cells with different morphology in all three leucocyte preparations phagocytised beads rapidly. Due to lack of available cell markers, the identity of the phagocytic cells could not be determined. The potent non-specific phagocytosis was in accordance with a high number of cells positive for myeloperoxidase, an enzyme involved in oxygen-dependent killing mechanism present in phagocytic cells. Further, high respiratory burst activity was present in the leucocytes samples, verifying a potent oxygen- dependent degradation. At present, the specific antibody immune response could not be measured, as immunoglobulin or B-cells have not yet been isolated. Therefore, analyses of the specific immune response in this fish species await further clarification. The present study presents the first analyses of lumpsucker immunity and also the first within the order Scopaeniformes. PMID:23112870

  6. Phagocytosis and respiratory burst activity in lumpsucker (Cyclopterus lumpus L.) leucocytes analysed by flow cytometry.

    PubMed

    Haugland, Gyri T; Jakobsen, Ragnhild Aakre; Vestvik, Nils; Ulven, Kristian; Stokka, Lene; Wergeland, Heidrun I

    2012-01-01

    In the present study, we have isolated leucocytes from peripheral blood, head kidney and spleen from lumpsucker (Cyclopterus lumpus L.), and performed functional studies like phagocytosis and respiratory burst, as well as morphological and cytochemical analyses. Different leucocytes were identified, such as lymphocytes, monocytes/macrophages and polymorphonuclear cells with bean shaped or bilobed nuclei. In addition, cells with similar morphology as described for dendritic cells in trout were abundant among the isolated leucocytes. Flow cytometry was successfully used for measuring phagocytosis and respiratory burst activity. The phagocytic capacity and ability were very high, and cells with different morphology in all three leucocyte preparations phagocytised beads rapidly. Due to lack of available cell markers, the identity of the phagocytic cells could not be determined. The potent non-specific phagocytosis was in accordance with a high number of cells positive for myeloperoxidase, an enzyme involved in oxygen-dependent killing mechanism present in phagocytic cells. Further, high respiratory burst activity was present in the leucocytes samples, verifying a potent oxygen- dependent degradation. At present, the specific antibody immune response could not be measured, as immunoglobulin or B-cells have not yet been isolated. Therefore, analyses of the specific immune response in this fish species await further clarification. The present study presents the first analyses of lumpsucker immunity and also the first within the order Scopaeniformes.

  7. Solubilization of the O2(-)-forming activity responsible for the respiratory burst in human neutrophils.

    PubMed

    Gabig, T G; Kipnes, R S; Babior, B M

    1978-10-10

    On exposure to suitable activating agents, neutrophils sharply alter their oxygen metabolism, showing large increases in oxygen uptake, O2 and H2O2 production, and glucose consumption via the hexose monophosphate shunt. These metabolic alterations, which together are designated the "respiratory burst," are due to the activation of a system which catalyzes the reaction: 2O2 + NADPH leads to 2O2(-) + NADP. This O2(-)-forming system is found in a particulate fraction isolated from neutrophils which had been activated with opsonized zymosan. When these particles were treated with detergent under suitable conditions, the O2(-)-forming activity was released in a form which passed through a membrane filter capable of retaining species of Mr greater than 3000,000. Soluble O2(-)-forming activity was obtained from normal activated neutrophils, but not from normal resting neutrophils or from activated neutrophils obtained from patients with chronic granulomatous disease, an inherited condition in which the respiratory burst is defective. O2(-)production by the soluble system required a reduced pyridine nucleotide as electron donor, and showed a quadratic dependence on the concentration of the solubilized preparation.

  8. Effect of 2-hydroxyethyl-methacrylate (HEMA) on the phagocytic and respiratory burst activity of human neutrophils and monocytes.

    PubMed

    Andersson, Jennie; Dahlgren, Ulf I

    2008-08-01

    Neutrophils and monocytes/macrophages (MØ), found in oral mucosa and gingival sulcus, phagocytose and kill bacteria using products produced during a respiratory burst. 2-Hydroxyethyl-methacrylate (HEMA) is a major component released from resin glass ionomer and dental adhesives. Hence, in pulp and gingiva, phagocytes can come into contact with unpolymerized HEMA monomers. The aim of this study was to examine the effects of exposure to HEMA on neutrophil and monocyte bactericidal function. Blood collected from five female volunteers was exposed in vitro to HEMA for 2 h and then phagocytosis, respiratory burst, and cellular integrity were measured using flow cytometry. Respiratory burst was quantified by measuring fluorescent rhodamine 123 generated via oxidation of dihydrorhodamine 123. Cellular membrane integrity was evaluated by staining with propidium iodide. The respiratory burst activity of the neutrophils was significantly decreased by exposure to 7.5 and 15 mM HEMA. No significant effect of HEMA was seen on the number of granulocytes or monocytes capable of performing respiratory burst. Furthermore, there was no significant effect of HEMA on the phagocytic activity of the monocytes or the granulocytes. In conclusion, HEMA did not affect the phagocytosis activity of neutrophils; however, the ability of the cells to kill internalized prey was significantly reduced.

  9. Respiratory burst activity of intestinal macrophages in normal and inflammatory bowel disease.

    PubMed Central

    Mahida, Y R; Wu, K C; Jewell, D P

    1989-01-01

    Macrophages isolated from normal mucosa (greater than 5 cm from tumour) and inflamed mucosa (from patients with inflammatory bowel disease) of colon and ileum were studied for their ability to undergo a respiratory burst as assessed by reduction of nitroblue tetrazolium to formazan. Using phorbol myristate acetate (PMA) and opsonised zymosan as triggers, only a minority (median: 8% for zymosan and 9% for PMA) of macrophages isolated from normal colonic mucosa demonstrated release of oxygen radicals. In contrast, a significantly greater (median: 17% for zymosan and 45% for PMA) proportion of macrophages isolated from inflamed colonic mucosa were able to undergo respiratory burst. Studies with normal and inflamed ileum showed similar results. Stimulation of macrophages isolated from normal colon with interferon-gamma produced only a small increase in the proportion of cells showing release of oxygen radicals. We conclude that the respiratory burst capacity of majority of macrophages isolated from normal colon and ileum is downregulated and a greater proportion of macrophages isolated from inflamed colon and ileum are able to undergo a respiratory burst. Images Fig. 2 PMID:2511088

  10. Flow cytometry analyses of phagocytic and respiratory burst activities and cytochemical characterization of leucocytes isolated from wrasse (Labrus bergylta A.).

    PubMed

    Haugland, Gyri T; Rønneseth, Anita; Wergeland, Heidrun I

    2014-07-01

    We have isolated leucocytes from peripheral blood (PBL), head kidney (HKL) and spleen (SL) of wrasse (Labrus bergylta A.) and studied the innate immune responses phagocytosis and respiratory burst using flow cytometry. Further, we have characterized the phenotypic properties of the leucocytes by cytochemical staining. We could differentiate between several subsets of leucocytes; lymphocytes, monocytes/macrophages, neutrophils, eosinophils, basophils and small leucocytes that might be precursor or immature cells. One striking observation was the eosinophils which were present among HKL, PBL and SL. The neutrophils had rounded, bean shaped or bi-lobed nuclei and resembled neutrophils in Atlantic cod (Gadus morhua L.) and lumpsucker (Cyclopterus lumpus L.), but were different from the polymorphonucleated neutrophils in Atlantic salmon (Salmo salar L.) and humans. Basophils were observed, but they were rare. Phagocytosis and respiratory burst activities were detected among different cell types. Highest phagocytic activity was observed among monocytes/macrophages and small leucocytes. Several different subtypes had ability to perform an oxygen-dependent degradation of microbes, measured as respiratory burst activity. Knowledge of the basic properties of wrasse's leucocytes and innate immunology can benefit further studies on its adaptive immune responses.

  11. Francisella noatunensis subsp. noatunensis replicates within Atlantic cod (Gadus morhua L.) leucocytes and inhibits respiratory burst activity.

    PubMed

    Vestvik, Nils; Rønneseth, Anita; Kalgraff, Cathrine A K; Winther-Larsen, Hanne C; Wergeland, Heidrun I; Haugland, Gyri T

    2013-09-01

    Francisella noatunensis subsp. noatunensis, causing granulomatosis in cod, has been shown to reside within cod immune cells, mainly within monocytes and macrophages. In the present study, we analysed the ability of the bacterium to replicate within adherent cells isolated from head kidney by in vitro infection of leucocytes. Two different technical approaches for flow cytometry analyses were performed for detection of intracellular bacteria. The presence of the wild type was assessed after identification by intracellular binding of specific antibodies to the pathogen. The other way was to use green fluorescent protein (GFP) transformed bacterium for infection studies allowing direct measurements of fluorescence from infected cells. By both methods we found an increase in fluorescence in infected cells, verifying bacterial replication, both after 4 and 28 h post infection in leucocytes isolated from head kidney (HKL). The GFP transformed bacterium was similar to the wild type in growth and infectivity pattern, showing that it can be a valuable tool for further studies of infection routes and pathology. Further, F. noatunensis subsp. noatunensis was found to inhibit respiratory burst activity, a potent pathogen killing mechanism, in cod leucocytes, but not in such cells from salmon. Our findings may indicate that inhibition of respiratory burst during Francisella infection is a key to its intracellular existence. This strategy seems to be conserved through evolution as it is also observed during infections in higher vertebrates caused by bacteria within the Francisella genus. The results presented here, showing the intracellular existence of Francisella, its replication within leucocytes and the inhibitory effect on respiratory burst, strongly support that these factors contribute to disease and pathology in infected cod. The intracellular replication shown in the present study might contribute to explain the problems of obtaining protective vaccines against

  12. Activation of the human neutrophil respiratory burst with zymosan-activated serum.

    PubMed

    Smith, R J; Iden, S S; Bowman, B J

    1984-06-15

    Zymosan-activated serum ( ZAS ) stimulated a time- and concentration-dependent generation of superoxide anion (O-2) by human neutrophils. O-2 production was rapid with maximum generation occurring 2 minutes after cell exposure to ZAS . O-2 generation is markedly reduced if cells are not preincubated with cytochalasin B prior to contact with ZAS . The amount of O-2 produced by ZAS stimulated neutrophils was enhanced in the presence of extra-cellular calcium. However, the intracellular calcium antagonist, 8-(N,N-diethylamino)-octyl-(3,4,5-trimethoxy) benzoate hydrochloride (TMB-8), caused a dose-related inhibition of ZAS -elicited O-2 production. Neutrophils pretreated with ZAS were desensitized to the subsequent exposure to this stimulus. The fact that pretreatment of neutrophils with ZAS did not diminish the capacity of these cells to generate O-2 in response to 1-O-hexadecyl/octadecyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (AGEPC),N-formyl-methionyl-leucyl-phenylalanine (FMLP) or 5(5),12(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid (LTB4), demonstrates the stimulus specific nature of ZAS -induced desensitization. Thus, ZAS , which contains the complement-derived neutrophil activator, C5a, a naturally occurring phlogistic mediator, represents a relevant probe for investigating neutrophil function.

  13. Spontaneous oscillatory burst activity in the piriform-amygdala region and its relation to in vitro respiratory activity in newborn rats.

    PubMed

    Onimaru, H; Homma, I

    2007-01-05

    The amygdala is important for the formation of emotions that are affected by olfactory information. The piriform cortex is involved in information processing related to olfaction. To investigate functional interactions between the piriform cortex and amygdala and their relation to medullary respiratory activity, we developed a novel in vitro preparation including the limbic system, brainstem, and spinal cord of newborn rats. With the use of optical and electrophysiologic recordings, we analyzed spontaneous neuronal activity in the piriform-amygdala complex in limbic-brainstem-spinal cord preparations from 0- to 1-day-old rats. For optical recordings, the preparation was stained with a voltage-sensitive dye, and inspiratory activity was monitored from the fourth cervical (C4) ventral root. Spontaneous oscillatory burst activity (up to 10/min) was detected from the rostral cut surface of limbic and para-limbic regions including the piriform cortex and amygdala. The burst activity initially appeared in the piriform cortex and then propagated to the amygdala. We averaged the imaging data in the limbic area with the use of C4 inspiratory activity as a trigger signal. The results suggest functional coupling of the rhythmic burst activity in the piriform-amygdala complex to medullary inspiratory activity, which was confirmed electrophysiologically by cross-correlation analysis of these signals. This rhythmic burst activity may be involved in the development of neuronal circuits that process information related to olfaction, emotion, and respiration.

  14. Rapid deactivation of NADPH oxidase in neutrophils: continuous replacement by newly activated enzyme sustains the respiratory burst.

    PubMed

    Akard, L P; English, D; Gabig, T G

    1988-07-01

    The cell-free system for activation of the neutrophil NADPH oxidase allowed us to examine activation of the oxidase in the absence of its NADPH-dependent turnover. The covalent sulfhydryl-modifying reagent N-ethylmaleimide completely inhibited the activation step (Ki = 40 mumol/L) in the cell-free system but had no effect on turnover of the preactivated particulate NADPH oxidase (up to 1 mmol/L). When N-ethylmaleimide was added to intact neutrophils during the period of maximal O2 generation in response to stimuli that activate the respiratory burst (phorbol myristate acetate, f-Met-Leu-Phe, opsonized zymosan, arachidonic acid), O2- generation ceased within seconds. Study of components of the cell-free activation system indicated that the cytosolic cofactor was irreversibly inhibited by N-ethylmaleimide whereas the N-ethylmaleimide-treated, membrane-associated oxidase could be activated by arachidonate and control cytosolic cofactor. Likewise, the cell-free system prepared from intact neutrophils that had been briefly exposed to N-ethylmaleimide and then washed reflected the effects of N-ethylmaleimide on the isolated cell-free components: cytosolic cofactor activity was absent, but the membrane oxidase remained fully activatable. Thus inhibition of oxidase activation by N-ethylamaleimide unmasked a rapid deactivation step that was operative in intact neutrophils but not in isolated particulate NADPH oxidase preparations. The demonstrated specificity of N-ethylmaleimide for oxidase activation and lack of effect on turnover of the NADPH oxidase suggested that sustained O2- generation by intact neutrophils was a result of continued replenishment of a small pool of active oxidase. The existence of an inactive pool of NADPH oxidase molecules in particulate preparations from stimulated neutrophils was supported more directly by activating these preparations again in the cell-free system.

  15. Immunomodulatory activity of diethylcarbamazine on humoral, cellular cytokine response and respiratory burst in BALB/c mice.

    PubMed

    Medina-De la Garza, Carlos E; Guerrero-Ramírez, Graciela; García-Hernández, Marisela; Castro-Corona, M Angeles; Torres-López, Ernesto; Brattig, Norbert W; Salinas-Carmona, Mario C

    2012-06-01

    Diethylcarbamazine (DEC) is an anthelmintic piperazine derivative drug with putative immunomodulating properties, including increased platelet and granulocyte adhesion to parasites and enhanced production of cytokines. To further analyse these properties in a well-established animal model, we evaluated the effect of DEC on antibody, cellular cytokine response and respiratory burst in BALB/c mice. Animals were challenged with a thymus-dependent (tetanus toxoid, (TT)) and with a thymus-independent (lipopolysaccharide, (LPS)) antigen and treated with DEC for seven days with two different doses (50 mg/day and 500 mg/day). Serum was assessed for antibody production at 0, 4, 7, 14, 21 and 28 days after stimulation and at 0, 24 and 48 h for IL-2, IFN-γ, IL-10 and IL-12 release. Respiratory burst of neutrophils and monocytes from peripheral blood was measured by flow cytometry. We found low-dose treatment with DEC enhanced cytokine production vs. TT and antibody production vs. LPS, whereas a higher dose enhanced significantly the respiratory burst of both polymorphonuclear leukocytes and monocytes, with a significant higher effect on the former. Our results suggest a stimulating, dose-dependent immunomodulatory effect of DEC with a higher effect on the phagocytic cells.

  16. The effects of oral consumption of selenium nanoparticles on chemotactic and respiratory burst activities of neutrophils in comparison with sodium selenite in sheep.

    PubMed

    Kojouri, Gholam Ali; Sadeghian, Sirous; Mohebbi, Abdonnaser; Mokhber Dezfouli, Mohammad Reza

    2012-05-01

    The present study was designed to compare the effects of nano-selenium and of sodium selenite on the chemotactic and respiratory burst activities of neutrophils in sheep. Fifteen sheep were randomly divided into three groups. Groups 1 and 2 received selenium nanoparticles (1 mg/kg) or sodium selenite (1 mg/kg) orally, respectively, for ten consecutive days, and the third group was considered as the control. To determine the chemotactic and respiratory burst activities of the neutrophils, the leading front assay and the NBT test were used on heparinized blood samples that were collected at different intervals (days 0, 10th, 20th, and 30th). The results obtained showed that the chemotactic activities in groups 1 and 2 increased significantly on the 10th, 20th, and 30th day, compared to day 0, and on the 20th day in comparison with the 10th day, while in group 2, there was a significant decrease on the 30th day compared to the 20th day. The chemotactic activities in group 1 were significantly higher than in group 2 on the 10th day and in the control group on the 10th, 20th, and 30th day, but the chemotactic activities in group 2 were significantly higher than those in the control group only on the 20th day. On the 30th day into the experiment, the respiratory bursts in groups 1 and 2 were significantly stronger in comparison with those at day 0. Overall, nano-selenium increased the chemotactic and respiratory burst activities more significantly than sodium selenite, which is suggestive of a stronger stimulatory effect of the Se nanoparticles on intracellular activities.

  17. Vanillin suppresses Kupffer cell-related colloidal carbon-induced respiratory burst activity in isolated perfused rat liver: anti-inflammatory implications.

    PubMed

    Galgani, José E; Núñez, Bárbara; Videla, Luis A

    2012-12-01

    The inhibition of NADPH oxidase has become a potential therapeutic target for oxidative stress-related diseases. We investigated whether vanillin modifies hepatic O(2) consumption associated with Kupffer cell functioning. The influence of vanillin on Kupffer cell functioning was studied in isolated perfused rat liver by colloidal carbon (CC) infusion (0.5 mg ml(-1)), concomitantly with sinusoidal efflux of lactate dehydrogenase (LDH) as an organ viability parameter. CC infusion increased the rate of O(2) consumption of the liver above basal values, an effect that represents the respiratory burst activity of Kupffer cells. However, CC-dependent respiratory burst activity was suppressed by previous infusion of 2 mM vanillin. Vanillin did not affect the liver CC uptake rate and liver sinusoidal efflux of LDH efflux. These findings, elicited by vanillin, were reproduced by the well-established NADPH oxidase inhibitor apocynin. In conclusion, vanillin suppresses the respiratory burst activity of Kupffer cells as assessed in intact liver, which may be associated with the inhibition of macrophage NADPH oxidase activity. Such a finding may have relevance in conditions underlying Kupffer cell-dependent up-regulation of the expression and release of pro-inflammatory mediators by redox-dependent mechanisms.

  18. Ambroxol inhibits neutrophil respiratory burst activated by alpha chain integrin adhesion.

    PubMed

    Peroni, D G; Moser, S; Gallo, G; Pigozzi, R; Tenero, L; Zanoni, L; Boner, A L; Piacentini, G L

    2013-01-01

    The purpose of the present study was to investigate the possible anti-oxidant effect(s) of Ambroxol on neutrophils activated by ligand-binding of the drug with membrane-associated adhesion integrin CD11a and to estimate dose-response changes in oxygen free radical production. The amount of free radical production by anti-CD11a- and anti-CD4-coated neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine (FMLP) and challenged with increasing concentration of Ambroxol, was evaluated within a time frame of 90 minutes. A significant dose-dependent effect response of Ambroxol on O2‾ production by cells coated with anti-CD11a antibody was observed. This preliminary study opens a new perspective on the therapeutic role of Ambroxol as an antioxidant drug and for its potential use in controlling oxidative stress, particularly in leukocyte-dependent inflammation.

  19. Inhibitory effect of lactone fractions and individual components from three species of the Achillea millefolium complex of Bulgarian origin on the human neutrophils respiratory burst activity.

    PubMed

    Choudhary, Muhammad Iqbal; Jalil, Saima; Todorova, M; Trendafilova, A; Mikhova, B; Duddeck, H; Atta-ur-Rahman

    2007-09-01

    Achillea species are widely used in folk medicine for treatment of inflammatory diseases. The inhibitory effect on the human neutrophils respiratory burst activity of total extracts, their fractions and some main constituents of the flower heads from Achillea asplenifolia, A. collina and A. distans belonging to A. millefolium complex of Bulgarian origin, were tested by the modified method of Tan and Berridge. Seven from the investigated fractions showed activity similar or higher than that of indomethacine and might be evaluated as nonsteroidal anti-inflammatory agents.

  20. Effects of various extremely low frequency magnetic fields on the free radical processes, natural antioxidant system and respiratory burst system activities in the heart and liver tissues.

    PubMed

    Canseven, Ayse Gulnihal; Coskun, Sule; Seyhan, Nesrin

    2008-10-01

    Magnetic fields (MFs) can affect biological systems by increasing the release of free radicals that are able to alter cell defense systems and breakdown tissue homeostasis. In the present study, the effects of extremely low frequency (ELF) electromagnetic fields (EMF) were investigated on free radical levels, natural antioxidant systems and respiratory burst system activities in heart and liver tissues of guinea pigs exposed to 50 Hz MFs of 1, 2 and 3 mT for 4 h/day and 8 h/day for 5 days by measuring malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH) levels and myeloperoxidase (MPO) activity. A total of sixty-two male guinea pigs, 10-12 weeks old were studied in seven groups as control and exposure groups: Group I (control), II (1 mT, 4 h/day), III (1 mT, 8 h/day), IV (2 mT, 4 h/day), V (2 mT, 8 h/day), VI (3 mT, 4 h/day), and VII (3 mT, 8 h/day). Controls were kept under the same conditions without any exposure to MF. MDA levels increased in liver in groups II and IV, but decreased in group VII for both liver and heart tissues. NOx levels declined in heart in groups II and III and in liver in groups III, V, and VI, but increased in liver in group VII. GSH levels increased in heart in groups II, IV, V, and in liver in groups V and VI and VI, but decreased in groups II and IV in liver. MPO activity decreased in liver in groups III, IV, VI and VII with respect to controls and in heart tissues in groups II, III and IV; however, there was a significant increase MPO activity in heart in group VII. From the results, it can be concluded that the intensity and exposure duration of MFs are among the effective conditions on the formation of free radicals and behaviour of antioxidant enzymes.

  1. Repeatability of flow cytometric and classical measurement of phagocytosis and respiratory burst in bovine polymorphonuclear leukocytes.

    PubMed

    Kampen, Annette H; Tollersrud, Tore; Larsen, Stig; Roth, James A; Frank, Dagmar E; Lund, Arve

    2004-01-01

    Five methods for measurement of phagocytosis and respiratory burst activity of bovine blood polymorphonuclear leukocytes (PMNs) were evaluated. Eight cows were repeatedly sampled over a two week period and parallel samples tested in all five assays to assess the repeatability and stability of the methods. In the flow cytometric phagocytosis assay, ingestion of fluorescein labeled bacteria was measured, and in the flow cytometric assay for respiratory burst, oxidation of a dye by reactive oxygen species was recorded. In the classical assays, bactericidal effect on opsonized, live bacteria was quantified by the conversion of an indicator substance, superoxide anion production was assayed by the reduction of cytochrome c, whereas myeloperoxidase activity was determined with a radioactive iodination assay. The results showed that the Phagotest, Bursttest, cytochrome c and iodination assays gave repeatable results when samples were run in the same setup on the same day. Although day-to-day variability was significant in all assays, the described methods comprise a panel of useful tests for the evaluation of phagocytosis and respiratory burst activity in bovine PMNs. The flow cytometric methods represent a convenient alternative to the classical methods for measurement of phagocytosis and respiratory burst in bovine blood PMNs.

  2. Proton stoichiometry associated with human neutrophil respiratory-burst reactions.

    PubMed

    Gabig, T G; Lefker, B A; Ossanna, P J; Weiss, S J

    1984-11-10

    Control of the intraphagosomal pH in neutrophils may be of importance in creating a microbicidal environment by regulating the activity of the O2-.-generating NADPH oxidase and the lysosomal enzymes discharged into this compartment. In this study, we examined the proton stoichiometry associated with the primary enzymatic reaction underlying the respiratory burst. A preparation of the neutrophil-derived, membrane oxidase consumed NADPH and generated O2-. with a stoichiometry of 1 NADPH:2 O2-. When the enzymatically produced O2-. was prevented from undergoing dismutation, net protons were released in an approximate 1:2 stoichiometry with O2-. generated. In contrast, when O2-. was allowed to dismutate to H2O2, net protons were consumed in a 1:1 stoichiometry with the accumulated H2O2. Thus, the delta pH associated with the NADPH oxidase-dependent production of O2-. was dictated by the fate of the generated radical. The consumption of the oxidase-generated H2O2 by the lysosomal enzyme myeloperoxidase resulted in the formation of HOCl which was trapped in the presence of taurine as the N-chloro derivative. The ratio of chlorinated product formed to H+ consumed was 1:1. The implications of these results are discussed in terms of the known intraphagosomal pH changes that occur following neutrophil stimulation. We conclude that the O2-.-generating oxidase plays a dual role in the phagosome by simultaneously creating an oxidizing environment that optimizes pH-dependent microbicidal processes.

  3. Superoxide produced by activated neutrophils efficiently reduces the tetrazolium salt, WST-1 to produce a soluble formazan: a simple colorimetric assay for measuring respiratory burst activation and for screening anti-inflammatory agents.

    PubMed

    Tan, A S; Berridge, M V

    2000-04-21

    Activation of the respiratory burst of granulocytes and macrophages by invading microorganisms is a key first line cellular defence against infection. Failure to generate this response leads to persistent life-threatening infection unless appropriate antibiotic treatment is given. The respiratory burst of neutrophils is usually measured spectrophotometrically by following ferricytochrome c reduction, and histologically by using the tetrazolium salt, nitroblue tetrazolium, which is reduced intracellularly to an insoluble formazan. In both assays, reduction is mediated by superoxide generated via NADPH oxidase. Because ferricytochrome c has a high molecular mass and high background absorbance at 550 nm, the assay lacks sensitivity and is not ideally suited to microplate measurement. We have circumvented these limitations by using the cell-impermeable, sulfonated tetrazolium salt, WST-1, which exhibits very low background absorbance and is efficiently reduced by superoxide to a stable water-soluble formazan with high molar absorptivity. This has permitted adaptation of the WST-1 assay to microplate format while retaining sensitivity. Reduction of WST-1 by activated human peripheral blood neutrophils correlated closely with ferricytochrome c reduction across a range of PMA concentrations and with time of activation by PMA and fMLP. Reduction of WST-1 was inhibited by 98% by superoxide dismutase (20 microg/ml) and by 88% by the NADPH oxidase inhibitor, diphenyleneiodinium (10 microM) but was resistant to catalase, azide and the NADH oxidase inhibitor, resiniferatoxin. WST-1 and ferricytochrome c reduction were also compared using xanthine/xanthine oxidase to generate superoxide. Under optimised assay conditions, both WST-1 and ferricytochrome c reduction were directly proportional to added xanthine. WST-1 generated approximately 2-fold greater increase in absorbance than ferricytochrome c at their respective wavelengths, and this translated into increased assay

  4. Intracellular shunting of O{sub 2}{sup −} contributes to charge compensation and preservation of neutrophil respiratory burst in the absence of voltage-gated proton channel activity

    SciTech Connect

    Decleva, Eva; Menegazzi, Renzo; Fasolo, Alba; Defendi, Federica

    2013-07-15

    Proton efflux via voltage-gated proton channels (Hv1) is considered to mediate the charge compensation necessary to preserve NADPH oxidase activity during the respiratory burst. Using the Hv1 inhibitor Zn{sup 2+}, we found that the PMA-induced respiratory burst of human neutrophils is inhibited when assessed as extracellular production of O{sub 2}{sup −} and H{sub 2}O{sub 2}, in accordance with literature studies, but, surprisingly, unaffected when measured as oxygen consumption or total (extracellular plus intracellular) H{sub 2}O{sub 2} production. Furthermore, we show that inhibiting Hv1 with Zn{sup 2+} results in an increased production of intracellular ROS. Similar results, i.e. decreased extracellular and increased intracellular ROS production, were obtained using a human granulocyte-like cell line with severely impaired Hv1 expression. Acidic extracellular pH, which dampens proton efflux, also augmented intracellular production of H{sub 2}O{sub 2}. Zinc caused an increase in the rate but not in the extent of depolarization and cytosolic acidification indicating that mechanisms other than proton efflux take part in charge compensation. Our results suggest a hitherto unpredicted mechanism of charge compensation whereby, in the absence of proton efflux, part of O{sub 2}{sup −} generated within gp91{sup phox} in the plasma membrane is shunted intracellularly down electrochemical gradient to dampen excessive depolarization. This would preserve NADPH oxidase activity under conditions such as the inflammatory exudate in which the acidic pH hinders charge compensation by proton efflux. Highlights: • Neutrophils’ respiratory burst is not inhibited by the H{sup +} channel inhibitor Zn{sup 2+}. • Intracellular production of O{sub 2}{sup −} and H{sub 2}O{sub 2} is increased in the presence of Zn{sup 2+}. • Intracellular H{sub 2}O{sub 2} production is increased in H{sup +} channels knock-down cells. • Zn{sup 2+} increases the rate but not the extent of

  5. What doesn't kill you makes you stronger: the anti-inflammatory effect of neutrophil respiratory burst.

    PubMed

    Borregaard, Niels

    2014-01-16

    In this issue of Immunity, Campbell et al. (2014) demonstrate that hypoxia caused by the respiratory burst of infiltrating neutrophils activates hypoxia inducible factor (HIF) in epithelial cells and protects the mucosa cells in an experimental model of inflammatory bowel disease.

  6. The activation of the neutrophil respiratory burst by anti-neutrophil cytoplasm autoantibody (ANCA) from patients with systemic vasculitis requires tyrosine kinases and protein kinase C activation

    PubMed Central

    Radford, D J; Lord, J M; Savage, C O S

    1999-01-01

    The ability of antineutrophil cytoplasm autoantibodies (ANCA) from patients with systemic vasculitis to stimulate protein kinase C (PKC) and tyrosine kinases was examined in human neutrophils. Using the superoxide dismutase-inhibitable reduction of ferricytochrome C, the kinetics of ANCA-induced superoxide (O2−) production were characterized and subsequently manipulated by specific inhibitors of PKC and tyrosine kinases. With this approach, ANCA IgG, but not normal IgG or ANCA F(ab′)2 fragments caused a time and dose dependent release of O2− from TNF-α primed neutrophils. The kinetics of ANCA-induced O2− production showed an initial 10–15 min lag phase compared to the N-formyl-l-methionyl-l-leucyl-l-phenylalanine response, suggesting differences in the signalling pathways recruited by these two stimuli. Inhibitor studies revealed that ANCA-activation involved members of both the Ca2+-dependent and -independent PKC isoforms and also tyrosine kinases. ANCA IgG resulted in the translocation of the βII isoform of PKC at a time corresponding to the end of the lag phase of O2− production, suggesting that PKC activity may be instrumental in processes regulating the activity of the NADPH oxidase in response to ANCA. Tyrosine phosphorylation of numerous proteins also peaked 10–15 min after stimulation with ANCA but not normal IgG. These data suggest that PKC and tyrosine kinases regulate O2− production from neutrophils stimulated with autoantibodies from patients with systemic vasculitis. PMID:10540175

  7. Effects of oxygen tension and pH on the respiratory burst of human neutrophils.

    PubMed

    Gabig, T G; Bearman, S I; Babior, B M

    1979-06-01

    The respiratory burst of human neutrophils was measured under conditions of hypoxia and low pH. O2 -- production by neutrophils activated with opsonized zymosan fell slowly as the oxygen concentration declined to 1%, then dropped more sharply, reaching negligible levels at oxygen concentrations less than 0.25%. Production was half maximal at an oxygen concentration of 0.35% (equivalent to approximately 10-microM dissolved oxygen). O2- production by the cell-free O2- -forming system prepared from zymosan-activated neutrophils showed a similar dependence on oxygen concentration. A drop in pH caused decreases in both oxygen consumption and O2-- production by zymosan-treated neutrophils, values at PH 6.0 being 10%--20% of those observed at pH 7.5. Experiments with the cell-free O2-- -forming system suggested that this decline in respiratory burst activity at low pH was due to inefficient activation of the O2-- -forming enzyme under acidic conditions.

  8. Respiratory burst in alveolar macrophages exposed to urban particles is not a predictor of cytotoxicity.

    PubMed

    Breznan, Dalibor; Goegan, Patrick; Chauhan, Vinita; Karthikeyan, Subramanian; Kumarathasan, Prem; Cakmak, Sabit; Nadeau, Denis; Brook, Jeffrey R; Vincent, Renaud

    2013-06-01

    We examined the utility of respiratory burst measurements in alveolar macrophages to assess adverse cellular changes following exposure to urban particles. Cells were obtained by bronchioalveolar lavage of Fisher 344 rats and exposed (0-100 μg/well) to urban particles (EHC-93, SRM-1648, SRM-1649, PM2.5), the soluble (EHC-93sol) and insoluble (EHC-93insol) fractions of EHC-93 (EHC-93tot), mineral particles (TiO(2), SiO(2)) and metal oxides (iron III oxide, iron II/III oxide, copper II oxide, nickel II oxide). The particle-induced respiratory burst was measured by chemiluminescence for 2h after the addition of particles. The cells were then stimulated with phorbol 12-myristate 13-acetate (PMA), yeast Zymosan fragments (Zymosan), or lipopolysaccharide plus interferon-gamma (LPS/IFN-γ) and the stimulant-induced respiratory burst was measured. Independently of the potential of particles to induce directly a respiratory burst, exposure to most particles attenuated the subsequent stimulant-induced burst. The notable exception was SiO(2), which produced a strong respiratory burst upon contact with the macrophages and enhanced the subsequent response to PMA or LPS/IFN-γ. Based on the degree of inhibition of the stimulant-dependent respiratory burst, particles were clustered into groups of high (SRM-1649, iron III oxide), intermediate (EHC-93tot, EHC-93insol, SRM-1648, VERP, iron II/III oxide, copper II oxide), and low (EHC-93sol, SiO(2), TiO2 and nickel II oxide) potency. Across these clusters, the potency of the particles to inhibit the stimulant-dependent respiratory burst showed poor correlation with cytotoxicity determined by XTT reduction assay.

  9. Flow cytometry assays of respiratory burst in Atlantic salmon (Salmo salar L.) and in Atlantic cod (Gadus morhua L.) leucocytes.

    PubMed

    Kalgraff, Cathrine A K; Wergeland, Heidrun I; Pettersen, Eirin Fausa

    2011-09-01

    The oxidation of dihydrorhodamine 123 (DHR) to the fluorescent rhodamine 123 (RHO) was detected using flow cytometry. This assay for detection of respiratory burst activity was established in peripheral blood leucocytes (PBL) and head kidney leucocytes (HKL) of Atlantic salmon and Atlantic cod. The leucocytes were stimulated by phorbol 12-myristate 13-acetate (PMA). For cod cells 10 times lower concentration of PMA had to be used compared to salmon cells, as higher concentrations were toxic and resulted in considerable cell death. The cells found to be RHO-positive were monocytes/macrophages and neutrophils based on the scatter dot plots, but for salmon also some small cells were found to have high fluorescence intensity both in the flow cytometry analyses and by fluorescence microscopy of cytospin preparations. The nature of these cells is not known. For cod leucocytes, such cells were not obvious. The instrument settings are a bit more demanding for cod, as cod cells die more easily compared to salmon cells. In both assays the limit between negative and positive cells has to be carefully considered. The presented flow cytometry protocols for measurements of respiratory burst in salmon and cod leucocytes can be applied in various studies where respiratory burst functions are involved, such as to verify if it is activated or suppressed in connection with infections and immunostimulation.

  10. Methods: implementation of in vitro and ex vivo phagocytosis and respiratory burst function assessments in safety testing.

    PubMed

    Freebern, Wendy J; Bigwarfe, Tammy J; Price, Karen D; Haggerty, Helen G

    2013-01-01

    Functional innate immune assessments, including phagocytosis and respiratory burst, are at the forefront of immunotoxicology evaluation in pre-clinical animal species. Although in the clinic and in academic science, phagocytosis, and respiratory burst assessments have been reported for over two decades, the implementation of phagocytosis and respiratory burst analyses in toxicology safety programs is just recently gaining publicity. Discussed herein are general methods, both microtiter plate-based and flow cytometric-based, for assessing phagocytosis and respiratory burst in pre-clinical species including mouse, rat, dog, and monkey. This methods-centric discussion includes a review of technologies and descriptions of method applications, with examples of results from analyses testing reported inhibitors (rottlerin, wortmannin, and SB203580) of phagocytosis and respiratory burst. Justification of implementation, strategic experimental design planning, and feasibility aspects of evaluating test article effects on phagocytosis and respiratory burst function are described within the context of a case study. The case study involves investigation of the effects of a small molecule p38 kinase inhibitor, BMS-582949, on phagocytosis and respiratory burst functions in rat and monkey neutrophils and monocytes in vitro, as well as ex vivo in these innate immune cells from monkeys administered BMS-582949 during a 1-week repeat dose investigative study. The results of the in vitro and ex vivo assessments demonstrated that BMS-582949 inhibited phagocytosis and respiratory burst. These findings correlated with incidences of opportunistic infections observed in rat and monkey toxicity studies.

  11. Bursting Types and Bifurcation Analysis in the Pre-Bötzinger Complex Respiratory Rhythm Neuron

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Lu, Bo; Liu, Shenquan; Jiang, Xiaofang

    Many types of neurons and excitable cells could intrinsically generate bursting activity, even in an isolated case, which plays a vital role in neuronal signaling and synaptic plasticity. In this paper, we have mainly investigated bursting types and corresponding bifurcations in the pre-Bötzinger complex respiratory rhythm neuron by using fast-slow dynamical analysis. The numerical simulation results have showed that for some appropriate parameters, the neuron model could exhibit four distinct types of fast-slow bursters. We also explored the bifurcation mechanisms related to these four types of bursters through the analysis of phase plane. Moreover, the first Lyapunov coefficient of the Hopf bifurcation, which can decide whether it is supercritical or subcritical, was calculated with the aid of MAPLE software. In addition, we analyzed the codimension-two bifurcation for equilibria of the whole system and gave a detailed theoretical derivation of the Bogdanov-Takens bifurcation. Finally, we obtained expressions for a fold bifurcation curve, a nondegenerate Hopf bifurcation curve, and a saddle homoclinic bifurcation curve near the Bogdanov-Takens bifurcation point.

  12. The respiratory burst activity and expression of catalase in white shrimp, Litopenaeus vannamei, during long-term exposure to pH stress.

    PubMed

    Wang, Wei-Na; Li, Bao-Sheng; Liu, Jin-Jian; Shi, Lei; Alam, M J; Su, Shi-Juan; Wu, Juan; Wang, Lei; Wang, An-Li

    2012-08-01

    In this study, changes of reactive oxygen species (ROS) and the mRNA expression of catalase of the Pacific white shrimp, Litopenaeus vannamei, exposed to pH (5.4, 6.7, 8.0, and 9.3) stress was investigated at different stress time (24, 48, 72, 96, and 120 h). Level of malondialdehyde (MDA) in shrimp also were assessed. The results revealed that acidic (pH 5.4 and 6.7) or alkaline exposure (pH 9.3) induced production of ROS hemocytes and increase of MDA level in shrimp. Moreover, the catalase mRNA expression in hepatopancreas of L. vannamei was up-regulated in 24 h at pH 5.4, in 72 h at pH 6.7 and in 48 h at pH 9.3, whereas was down-regulated significantly after 72 h acidic (pH 5.4 and 6.7) or alkaline (pH 9.4) exposure. In the present study, there was the relationship between ROS and catalase mRNA expression under normal acidic and alkaline conditions. At pH 8, the increase of catalase transcripts due to up-regulation by ROS, whereas MDA level did not significantly change, suggesting activation of corresponding protective mechanisms of detoxifying ROS is essential for the proper functioning of cells and the survival of shrimps.

  13. The respiratory burst oxidase of human neutrophils. Further studies of the purified enzyme.

    PubMed

    Glass, G A; DeLisle, D M; DeTogni, P; Gabig, T G; Magee, B H; Markert, M; Babior, B M

    1986-10-05

    A superoxide-forming oxidase from activated human neutrophil membranes was solubilized by two slightly different methods, then purified by "dye-affinity" chromatography. Kinetic studies of the purified preparations gave Vmax values of 5-10 mumol of O-2/min/mg of protein, and Km values for NADH and NADPH that were in reasonable agreement with values determined previously using particulate and crude solubilized preparations of the respiratory burst oxidase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed prominent bands at 67, 48, and 32 kDa, together with some minor contaminants, whereas gel electrophoresis under non-denaturing conditions gave a single major band that when eluted and re-electrophoresed in the presence of sodium dodecyl sulfate showed bands at 67, 48, 32 kDa. We believe that all three bands represent oxidase components. The flavin content of the purified enzyme was 20.4 +/- 2.0 S.E. pmol of FAD/microgram of protein, whereas heme averaged 0.1 +/- 0.02 pmol/microgram and ubiquinone could not be detected. Assuming that the enzyme is composed of one 67-kDa subunit, one 48-kDa subunit, and one 32-kDa subunit (i.e. that its molecular mass is approximately 150 kDa), it can be calculated to have a turnover number of 700-1500 min-1, in agreement with a value reported previously for oxidase in a particulate O-2-forming system (Cross, A. R., Parkinson, J. F., and Jones, O. T. G. (1985) Biochem. J. 226, 881-884), and to contain the following quantities of redox carriers (mol/mol): FAD, 3.0; heme, 0.015; ubiquinone, less than 0.06. It remains to be determined whether this preparation represents the complete respiratory burst oxidase or is only the pyridine nucleotide dehydrogenating component of a more complex enzyme.

  14. Effect of magnetic resonance imaging on human respiratory burst of neutrophils.

    PubMed

    Heine, J; Scheinichen, D; Jaeger, K; Herzog, T; Sümpelmann, R; Leuwer, M

    1999-03-05

    It is known that low intensity magnetic fields increase superoxide anion production during the respiratory burst of rat peritoneal neutrophils in vitro. We investigated whether the high intensity magnetic fields (1.5 T) during magnetic resonance imaging can influence the human neutrophil function under in vivo conditions. Blood samples were obtained from 12 patients immediately before and after magnetic resonance imaging (mean time 27.6(+/-11.4 min)). The induced respiratory burst was investigated by the intracellular oxidative transformation of dihydrorhodamine 123 to the fluorescent dye rhodamine 123 via flow cytometry. The respiratory burst was induced either with phorbol 12-myristate 13-acetate, Escherichia coli, N-formyl-methionyl-leucylphenylalanine or priming with tumor necrosis factor followed by FMLP stimulation. There was no significant difference between the respiratory burst before and after magnetic resonance imaging, irrespective of the stimulating agent. Short time exposure to a high intensity magnetic field during magnetic resonance imaging seems not to influence the production of radical species in living neutrophils.

  15. Isolation of the respiratory burst oxidase: the role of a flavoprotein component.

    PubMed

    Parkinson, J F; Gabig, T G

    1988-12-01

    The article reviews the enzymatic and electron transfer properties of a low-potential FAD-dependent flavoprotein that is a component of the NADPH-dependent O2-.-generating respiratory burst oxidase of phagocytes. Current methods available for isolation of the respiratory burst oxidase and the flavoprotein component of the complex are also reviewed. These studies and data obtained from affinity-labeling of respiratory burst oxidase components, suggest that the flavoprotein has a molecular weight of 65-67 kD. The prevailing evidence suggests that the flavoprotein functions as a dehydrogenase/electron transferase and can directly catalyse NADPH-dependent O2-.formation when isolated. However, in neutrophil plasma membranes, the prevailing evidence suggests that the flavoprotein functions primarily to transfer electrons from NADPH to cytochrome b-245 and that this latter redox component is the catalytic side of O2-.formation. A working model for the arrangement of the flavoprotein and cytochrome b-245 components of the respiratory burst oxidase in neutrophil membranes is proposed.

  16. Bacterial N-formyl Peptides Reduce PMA- and E.coli-induced Neutrophil Respiratory Burst in Term Neonates and Adults.

    PubMed

    Stålhammar, Maria E; Douhan Håkansson, Lena; Sindelar, Richard

    2017-02-15

    Neutrophil migration and respiratory burst is the prerequisite for efficient first line defense against invading microorganisms. However, migration and respiratory burst can be compromised in adults and especially in newborn infants, where sustained neutrophil accumulation, uncontrolled burst and reduced scavenging of ROS might cause inadvertent tissue damage due to uncontrolled inflammation. The aim of this study was to investigate the modulatory effect of the chemoattractants formyl-methionyl-leucyl-phenylalanine (fMLP) and IL-8 on respiratory burst in neutrophils from term newborn infants and adults. Whole blood from the umbilical cord of 17 healthy term newborn infants delivered by caesarean section and from 17 healthy adults as reference was preincubated with fMLP or IL-8 and stimulated with PMA or E.coli bacteria. Respiratory burst was quantified by flow cytometry analysis of dihydrorhodamine 123 fluorescence. fMLP reduced the PMA-induced respiratory burst of neutrophils from newborn infants and adults by 12% and 21% respectively (p<0.05). E.coli-induced burst was also reduced by fMLP in neutrophils from newborn infants (10%; p<0.01) and adults (6%; p<0.05). No such changes were observed with IL-8. Similar respiratory burst in response to single stimulus with PMA or E.coli were observed in both newborn infants and adults. fMLP reduced PMA- and E.coli-induced respiratory burst of neutrophils in whole blood from term newborn infants as well as in adults. The reduced respiratory burst by fMLP might be a mechanism to reduce the detrimental effects of uncontrolled inflammation during neutrophil migration. This article is protected by copyright. All rights reserved.

  17. Standardization of the antibody-dependent respiratory burst assay with human neutrophils and Plasmodium falciparum malaria.

    PubMed

    Llewellyn, David; Miura, Kazutoyo; Fay, Michael P; Williams, Andrew R; Murungi, Linda M; Shi, Jianguo; Hodgson, Susanne H; Douglas, Alexander D; Osier, Faith H; Fairhurst, Rick M; Diakite, Mahamadou; Pleass, Richard J; Long, Carole A; Draper, Simon J

    2015-09-16

    The assessment of naturally-acquired and vaccine-induced immunity to blood-stage Plasmodium falciparum malaria is of long-standing interest. However, the field has suffered from a paucity of in vitro assays that reproducibly measure the anti-parasitic activity induced by antibodies in conjunction with immune cells. Here we optimize the antibody-dependent respiratory burst (ADRB) assay, which assesses the ability of antibodies to activate the release of reactive oxygen species from human neutrophils in response to P. falciparum blood-stage parasites. We focus particularly on assay parameters affecting serum preparation and concentration, and importantly assess reproducibility. Our standardized protocol involves testing each serum sample in singlicate with three independent neutrophil donors, and indexing responses against a standard positive control of pooled hyper-immune Kenyan sera. The protocol can be used to quickly screen large cohorts of samples from individuals enrolled in immuno-epidemiological studies or clinical vaccine trials, and requires only 6 μL of serum per sample. Using a cohort of 86 samples, we show that malaria-exposed individuals induce higher ADRB activity than malaria-naïve individuals. The development of the ADRB assay complements the use of cell-independent assays in blood-stage malaria, such as the assay of growth inhibitory activity, and provides an important standardized cell-based assay in the field.

  18. Bursts of activity in collective cell migration

    PubMed Central

    Chepizhko, Oleksandr; Giampietro, Costanza; Mastrapasqua, Eleonora; Nourazar, Mehdi; Ascagni, Miriam; Sugni, Michela; Fascio, Umberto; Leggio, Livio; Malinverno, Chiara; Scita, Giorgio; Santucci, Stéphane; Alava, Mikko J.; Zapperi, Stefano; La Porta, Caterina A. M.

    2016-01-01

    Dense monolayers of living cells display intriguing relaxation dynamics, reminiscent of soft and glassy materials close to the jamming transition, and migrate collectively when space is available, as in wound healing or in cancer invasion. Here we show that collective cell migration occurs in bursts that are similar to those recorded in the propagation of cracks, fluid fronts in porous media, and ferromagnetic domain walls. In analogy with these systems, the distribution of activity bursts displays scaling laws that are universal in different cell types and for cells moving on different substrates. The main features of the invasion dynamics are quantitatively captured by a model of interacting active particles moving in a disordered landscape. Our results illustrate that collective motion of living cells is analogous to the corresponding dynamics in driven, but inanimate, systems. PMID:27681632

  19. Resveratrol and curcumin reduce the respiratory burst of Chlamydia-primed THP-1 cells.

    PubMed

    Deby-Dupont, Ginette; Mouithys-Mickalad, Ange; Serteyn, Didier; Lamy, Maurice; Deby, Carol

    2005-07-22

    The intracellular bacterium Chlamydia pneumoniae is involved in the inflammation process of atherosclerosis. We previously demonstrated that C. pneumonia infected monocytes (THP-1 cells) responded to stimulation by an increased respiratory burst linked to an increased NADPH oxidase (NOX) activity. We now tested agents acting on the assembly of the NOX subunits or on protein kinase C, a trigger of NOX activity. Apocynin, resveratrol, rutin, quercetin, curcumin, and tocopherols were tested. The cells were pre-incubated with Chlamydia and the agent for 19 h, and then stimulated with phorbol myristate acetate. The NOX activity was monitored by measuring the hydrogen peroxide production. Resveratrol and curcumin (10(-4)-10(-6) M) were better inhibitors than apocynin. alpha-Tocopherol was inactive, and gamma-tocopherol inhibitor at 10(-4) M only. Quercetin was inactive, and rutin a moderate but significant inhibitor. The inhibition by resveratrol was increased by 10(-6) M rutin or quercetin. Resveratrol and curcumin thus appeared to be interesting for atherosclerosis treatment.

  20. Influence of Rhodococcus equi on the respiratory burst of resident alveolar macrophages from horses

    SciTech Connect

    Brumbaugh, G.W.

    1986-01-01

    Rhodococcus equi is the etiologic agent of a devastating pneumonia of sporadic incidence in foals. The purpose of this study was to evaluate the influence of R. equi on the superoxide anion production, measured spectrophotometrically as the reduction of cytochrome C, and hexose monophosphate shunt activity, measured by /sup 14/CO/sub 2/ liberation from /sup 14/C-1-D-glucose, of alveolar macrophages from horses. Alveolar macrophages were harvested from 6 anesthetized, healthy, light-breed, adult horses by bronchoalveolar lavage. Following a randomized complete block design, the suspension of cells was divided into aliquots of 10/sup 6/ viable alveolar macrophages which were exposed to 1, 10 or 100 g. of opsonized R. equi or opsonized zymosan A at 37 C for 2 hours. In this study the respiratory burst of equine alveolar macrophages was only evidenced by the hexose monophosphate shunt activity and superoxide anion was not coincidentally produced. Rhodococcus equi did not adversely affect that response. The insignificant superoxide anion production by the alveolar macrophages suggests that this may not be a significant oxygen metabolite in those cells.

  1. Inhibitory effects of leaf extracts of Stachytarpheta jamaicensis (Verbenaceae) on the respiratory burst of rat macrophages.

    PubMed

    Alvarez, Ezequiel; Leiro, José Manuel; Rodríguez, Melita; Orallo, Francisco

    2004-06-01

    The anti-oxidant effects of ethyl acetate (EAcE) and n-hexane extracts (nHE) of dried leaves of Stachytarpheta jamaicensis Vahl. (Verbenaceae) on the reactive oxygen species (ROS) generating during the respiratory burst of rat peritoneal macrophages were investigated. Only EAcE, at concentrations between 0.4 and 40 microg/ml, inhibited the extracellular release of oxygen radicals by resident peritoneal macrophages stimulated with phorbol-12-myristate 13-acetate (PMA). At concentrations above 40 microg/ml, EAcE inhibited the production of nitric oxide (NO) in macrophages stimulated in vivo with sodium thioglycollate then in vitro with lipopolysaccharide (LPS) and gamma-interferon (IFN-gamma). nHE extracts at concentrations between 0.4 and 40 microg/ml did not scavenge (O-)2 generated enzymatically by hypoxanthine/xanthine oxidase (HX/XO) system, but EAcE at the same concentrations showed potent (O-)2-scavenging activity. At 40 microg/ml, EAcE also inhibited XO activity. These results suggest that the EAcE extract of S. jamaicensis may be a potential pharmaceutical value in treatment of immunopathological diseases related to oxidative stress.

  2. Priming by grepafloxacin on respiratory burst of human neutrophils: its possible mechanism.

    PubMed

    Niwa, Masayuki; Kanamori, Yutaka; Hotta, Koichi; Matsuno, Hiroyuki; Kozawa, Osamu; Fujimoto, Sadaki; Uematsu, Toshihiko

    2002-10-01

    Grepafloxacin is a broad-spectrum fluoroquinolone derivative that has good tissue penetration. We demonstrated that grepafloxacin showed a priming effect on neutrophil respiratory burst, triggered by either a chemotactic factor N-formyl-methionyl-leucyl-phenylalanine (fMLP) or leukotriene B4 (LTB4), but not by the phorbol ester phorbol 12-myristate 13-acetate (PMA). The priming effect of grepafloxacin on fMLP-stimulated superoxide generation by human neutrophils correlated with the penetration of grepafloxacin into cells. Removal of extracellular grepafloxacin did not inhibit the priming effect on fMLP-stimulated superoxide generation. Furthermore, grepafloxacin induced the translocation of p47-phox and p67-phox to the membrane fraction of neutrophils, whereas tyrosine phosphorylation was hardly observed in neutrophils exposed to grepafloxacin. The priming effect of grepafloxacin on superoxide generation from neutrophils was not inhibited by treatment with pertussis toxin, a protein-tyrosine kinase inhibitor (ST-638) or a protein kinase C inhibitor (calphostin C), or chelation of extracellular calcium. Grepafloxacin did not change the fMLP receptor-binding properties. Taken together, these findings suggest that grepafloxacin evokes a priming effect on neutrophil superoxide generation intracellularly through the translocation of p47-phox and even p67-phox protein to the membrane fractions. GTP binding protein, protein-tyrosine phosphorylation and protein kinase C activation are not involved in the priming effect.

  3. Source and role of diacylglycerol formed during phagocytosis of opsonized yeast particles and associated respiratory burst in human neutrophils

    SciTech Connect

    Della Bianca, V.; Grzeskowiak, M.; Lissandrini, D.; Rossi, F. )

    1991-06-28

    The results presented in this paper demonstrate that in human neutrophils phagocytosis of C3b/bi and IgG-opsonized yeast particles is associated with activation of phospholipase D and that this reaction is the main source of diglycerides. The demonstration is based upon the following findings: (1) the challenge of neutrophils with these opsonized particles was followed by a rapid formation of (3H)alkyl-phosphatidic acid (( 3H)alkyl-PA) and (3H)alkyl-diglyceride (( 3H)alkyl-DG) in cells labeled with (3H)alkyl-lyso-phosphatidylcholine; (2) in the presence of ethanol (3H)alkyl-phosphatidylethanol was formed, and accumulation of (3H)alkyl-PA and (3H)alkyl-DG was depressed; (3) propranolol, by inhibiting the dephosphorylation of (3H)alkyl-PA, completely inhibited the accumulation of (3H)alkyl-DG and depressed by about 75% the formation of diglyceride mass. Evidence is also presented that phagocytosis of C3b/bi and IgG-opsonized yeast particles and associated respiratory burst can take place independently of diglyceride formation and of the activity of this second messenger on protein kinase C. In fact: (a) propranolol while completely inhibited the formation of diglyceride mass did not modify either the phagocytosis or respiratory burst; (b) these two processes were insensitive to staurosporine.

  4. Respiratory burst facilitates the digestion of Escherichia coli killed by polymorphonuclear leukocytes.

    PubMed Central

    Weiss, J; Kao, L; Victor, M; Elsbach, P

    1987-01-01

    We examined factors that may limit degradation of bacterial protein of Escherichia coli S15 killed by polymorphonuclear leukocytes (PMN). Both human and rabbit PMN degraded up to 40% of [14C]amino acid-labeled protein of ingested and killed E. coli in 2 h as determined by loss of acid-precipitable radioactivity. In contrast, equally bactericidal broken-PMN preparations or isolated granules degraded only about 10% of bacterial protein regardless of pH. To determine whether activation of the respiratory burst contributes to digestion, we compared degradation by intact PMN in room air and under N2. Depletion of O2 by N2 flushing had no effect on the bactericidal activity of either human or rabbit PMN but reduced degradation by approximately 50%. Protein degradation during phagocytosis was also reduced in the presence of cyanide or azide, inhibitors of myeloperoxidase (MPO). PMN of two patients with chronic granulomatous disease ingested and killed E. coli S15 as well as did normal PMN but degraded bacterial protein as did normal PMN incubated under N2. The low degradative activity of PMN disrupted by sonication could be raised to nearly the level of intact PMN incubated in room air by preincubation of the PMN with 10(-7) M formyl-methionyl-leucyl-phenylalanine (fMLP) before sonication and by pretreatment of E. coli with MPO. Depletion of O2 or chloride during these preincubations with formyl-methionyl-leucyl-phenylalanine respectively, virtually abolished and markedly diminished stimulation of bacterial protein degradation. We conclude that enhanced MPO-mediated O2 metabolism of intact PMN plays a role in the digestion of killed E. coli. PMID:3305366

  5. Phasic Motor Activity of Respiratory and Non-Respiratory Muscles in REM Sleep

    PubMed Central

    Fraigne, Jimmy J.; Orem, John M.

    2011-01-01

    Objectives: In this study, we quantified the profiles of phasic activity in respiratory muscles (diaphragm, genioglossus and external intercostal) and non-respiratory muscles (neck and extensor digitorum) across REM sleep. We hypothesized that if there is a unique pontine structure that controls all REM sleep phasic events, the profiles of the phasic twitches of different muscle groups should be identical. Furthermore, we described how respiratory parameters (e.g., frequency, amplitude, and effort) vary across REM sleep to determine if phasic processes affect breathing. Methods: Electrodes were implanted in Wistar rats to record brain activity and muscle activity of neck, extensor digitorum, diaphragm, external intercostal, and genioglossal muscles. Ten rats were studied to obtain 313 REM periods over 73 recording days. Data were analyzed offline and REM sleep activity profiles were built for each muscle. In 6 animals, respiratory frequency, effort, amplitude, and inspiratory peak were also analyzed during 192 REM sleep periods. Results: Respiratory muscle phasic activity increased in the second part of the REM period. For example, genioglossal activity increased in the second part of the REM period by 63.8% compared to the average level during NREM sleep. This profile was consistent between animals and REM periods (η2 = 0.58). This increased activity seen in respiratory muscles appeared as irregular bursts and trains of activity that could affect rythmo-genesis. Indeed, the increased integrated activity seen in the second part of the REM period in the diaphragm was associated with an increase in the number (28.3%) and amplitude (30%) of breaths. Non-respiratory muscle phasic activity in REM sleep did not have a profile like the phasic activity of respiratory muscles. Time in REM sleep did not have an effect on nuchal activity (P = 0.59). Conclusion: We conclude that the concept of a common pontine center controlling all REM phasic events is not supported by our

  6. Bursts of Active Transport in Living Cells

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Kuo, James; Granick, Steve

    2013-11-01

    We show, using a large new data set, that the temporally resolved speed of active cargo transport in living cells follows a scaling law over several decades of time and length. The statistical regularities display a time-averaged shape that we interpret to reflect stress buildup, followed by rapid release. The scaling power law agrees quantitatively with those reported in inanimate systems (jammed colloids and granular media, and magnetic Barkhausen noise), suggesting a common origin in pushing through a crowded environment in a weak force regime. The implied regulation of the speed of active cellular transport due to environmental obstruction results in bursts of speed and acceleration. These findings extend the classical notion of molecular crowding.

  7. Bursts of active transport in living cells.

    PubMed

    Wang, Bo; Kuo, James; Granick, Steve

    2013-11-15

    We show, using a large new data set, that the temporally resolved speed of active cargo transport in living cells follows a scaling law over several decades of time and length. The statistical regularities display a time-averaged shape that we interpret to reflect stress buildup, followed by rapid release. The scaling power law agrees quantitatively with those reported in inanimate systems (jammed colloids and granular media, and magnetic Barkhausen noise), suggesting a common origin in pushing through a crowded environment in a weak force regime. The implied regulation of the speed of active cellular transport due to environmental obstruction results in bursts of speed and acceleration. These findings extend the classical notion of molecular crowding.

  8. Comparative study of β-glucan induced respiratory burst measured by nitroblue tetrazolium assay and real-time luminol-enhanced chemiluminescence assay in common carp (Cyprinus carpio L.).

    PubMed

    Vera-Jimenez, N I; Pietretti, D; Wiegertjes, G F; Nielsen, M E

    2013-05-01

    The respiratory burst is an important feature of the immune system. The increase in cellular oxygen uptake that marks the initiation of the respiratory burst is followed by the production of reactive oxygen species (ROS) such as superoxide anion and hydrogen peroxide which plays a role in the clearance of pathogens and tissue regeneration processes. Therefore, the respiratory burst and associated ROS constitute important indicators of fish health status. This paper compares two methods for quantitation of ROS produced during the respiratory burst in common carp: the widely used, single-point measurement based on the intracellular reduction of nitroblue tetrazolium (NBT) and a real-time luminol-enhanced assay based on the detection of native chemiluminescence. Both assays allowed for detection of dose-dependent changes in magnitude of the respiratory burst response induced by β-glucans in head kidney cells of carp. However, whereas the NBT assay was shown to detect the production of only superoxide anions, the real-time luminol-enhanced assay could detect the production of both superoxide anions and hydrogen peroxide. Only the chemiluminescence assay could reliably record the production of ROS on a real-time scale at frequent and continual time intervals for time course experiments, providing more detailed information on the respiratory burst response. The real-time chemiluminescence assay was used to measure respiratory burst activity in macrophage and neutrophilic granulocyte-enriched head kidney cell fractions and total head kidney cell suspensions and proved to be a fast, reliable, automated multiwell microplate assay to quantitate fish health status modulated by β-glucans.

  9. Sympathetic network drive during water deprivation does not increase respiratory or cardiac rhythmic sympathetic nerve activity.

    PubMed

    Holbein, Walter W; Toney, Glenn M

    2013-06-15

    Effects of water deprivation on rhythmic bursting of sympathetic nerve activity (SNA) were investigated in anesthetized, bilaterally vagotomized, euhydrated (control) and 48-h water-deprived (WD) rats (n = 8/group). Control and WD rats had similar baseline values of mean arterial pressure, heart rate, end-tidal CO2, and central respiratory drive. Although integrated splanchnic SNA (sSNA) was greater in WD rats than controls (P < 0.01), analysis of respiratory rhythmic bursting of sSNA revealed that inspiratory rhythmic burst amplitude was actually smaller (P < 0.005) in WD rats (+68 ± 6%) than controls (+208 ± 20%), and amplitudes of the early expiratory (postinspiratory) trough and late expiratory burst of sSNA were not different between groups. Further analysis revealed that water deprivation had no effect on either the amplitude or periodicity of the cardiac rhythmic oscillation of sSNA. Collectively, these data indicate that the increase of sSNA produced by water deprivation is not attributable to either increased respiratory or cardiac rhythmic burst discharge. Thus the sympathetic network response to acute water deprivation appears to differ from that of chronic sympathoexcitation in neurogenic forms of arterial hypertension, where increased respiratory rhythmic bursting of SNA and baroreflex adaptations have been reported.

  10. Factors influencing in vitro respiratory burst assays with head kidney leucocytes from rainbow trout, Oncorhynchus mykiss (Walbaum).

    PubMed

    Chettri, J K; Holten-Andersen, L; Buchmann, K

    2010-07-01

    Abstract Head kidney leucocytes are central elements in a number of in vivo and in vitro assays elucidating innate and adaptive immune mechanisms in teleosts following stimulation with various antigens. These systems are sensitive to several factors affecting the outcome of the assays. The present work describes the importance of temperature, cell concentration, exposure time and immune-modulatory molecules on the respiratory burst activity (RBA) of rainbow trout head kidney leucocytes in vitro. Some variation in RBA was observed among individual fish. However, use of cells pooled from four individuals produced satisfactory results following exposure to phorbol 12-myristate 13-acetate, zymosan and beta-glucan. Temperature was shown to have a significant effect on production of reactive radicals as illustrated by a high activity in cells maintained at 15-20 degrees C and a reduced activity at temperature extremes (1, 4 and 30 degrees C). Highest activity was found at a cell concentration of 1 x 10(7) cells mL(-1). Reactivity showed a clear decline when cells were exposed for more than 4 h. Moreover, incubation of cells with inhibitory substances viz., DiMePE2, cortisol and superoxide dismutase decreased the RBA. It is concluded that several biotic and abiotic factors should be taken into account when conducting RBA assays with head kidney leucocytes for elucidation of rainbow trout immune responses.

  11. Genome-Wide Analysis of Respiratory Burst Oxidase Homologs in Grape (Vitis vinifera L.)

    PubMed Central

    Cheng, Chenxia; Xu, Xiaozhao; Gao, Min; Li, Jun; Guo, Chunlei; Song, Junyang; Wang, Xiping

    2013-01-01

    Plant respiratory burst oxidase homolog (rboh) genes appear to play crucial roles in plant development, defense reactions and hormone signaling. In this study, a total of seven rboh genes from grape were identified and characterized. Genomic structure and predicted protein sequence analysis indicated that the sequences of plant rboh genes are highly conserved. Synteny analysis demonstrated that several Vvrboh genes were found in corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of the respective lineages. The expression pattern of Vvrboh genes in different tissues was assessed by qRT-PCR and two were constitutively expressed in all tissues tested. The expression profiles were similarly analyzed following exposure to various stresses and hormone treatments. It was shown that the expression levels of VvrbohA, VvrbohB and VvrbohC1 were significantly increased by salt and drought treatments. VvrbohB, VvrbohC2, and VvrbohD exhibited a dramatic up-regulation after powdery mildew (Uncinula necator (Schw.) Burr.) inoculation, while VvrbohH was down-regulated. Finally, salicylic acid treatment strongly stimulated the expression of VvrbohD and VvrbohH, while abscisic acid treatment induced the expression of VvrbohB and VvrbohH. These results demonstrate that the expression patterns of grape rboh genes exhibit diverse and complex stress-response expression signatures. PMID:24351809

  12. Peritoneal macrophages from patients with cirrhotic ascites show impaired phagocytosis and vigorous respiratory burst

    PubMed Central

    Ahmed, Abdel Motaal M.; Bomford, Adrian; Nouri-Aria, Kayhan T.; Davies, Ted; Smith, Roger; Williams, Roger

    2011-01-01

    Cirrhotic patients (CPs) are susceptible to spontaneous bacterial peritonitis (SBP). Aim of this study was to examine if this susceptibility was related to peritoneal macrophages' (PMs) altered host defence. Absorbance of phagocytosed particles by PMs from CPs was lower than that of control (31.88% vs. 77.2%). Particle opsonisation increased the absorbance to 41% in CPs' PMs, and this value remains lower than the control; 77.2%. Respiratory burst (RB) was expressed as fluorescence index values, and these were higher in PMs from CPs than in controls (82 vs. 41, 73 vs. 26 and 71 vs. 26). IFN-γ made no further increase of RB values in PMs from CPs. CD14 expression was also higher in CPs' PMs. IFN-γ significantly downregulated CD14 expression in both CPs' PMs and control. Reduced phagocytosis by predominantly CD14-positive PMs from CPs could be related to intense RB. Findings suggest altered host defence that could contribute to susceptibility to SBP. PMID:24371553

  13. Disparate effects of interferon-gamma and tumor necrosis factor-alpha on early neutrophil respiratory burst and fungicidal responses to Candida albicans hyphae in vitro.

    PubMed Central

    Diamond, R D; Lyman, C A; Wysong, D R

    1991-01-01

    We examined effects of priming with recombinant human interferon-gamma (IFN) or tumor necrosis factor-alpha (TNF) on neutrophil responses to Candida albicans hyphae. Both cytokines increased early superoxide generation after hyphal stimulation. The more pronounced effects of TNF were accompanied by an augmented surface membrane depolarization rate and were insensitive to both pertussis toxin and calcium ion chelation, but were negated by concomitant incubation with puromycin or cycloheximide during priming. IFN augmented hyphal killing despite its only minor enhancement of early respiratory burst responses, but TNF reduced neutrophil fungicidal activity to nearly 40% below those by unprimed control cells even though it enhanced early superoxide responses more dramatically. Though TNF-primed neutrophils killed hyphae at normal initial rates, IFN-primed or even unprimed cells manifested more fungicidal sustained activity. These disparate consequences of cytokine priming on hyphal destruction were paralleled by differences in late generation of potentially candidacidal oxidants, hydrogen peroxide, and hypochlorous acid. IFN added during priming failed to correct TNF-associated functional defects in neutrophil anti-Candida responses. Thus, augmentation of early respiratory burst responses to oxidant-sensitive organisms need not necessarily reflect concomitant salutary effects on microbicidal activity. Images PMID:1846880

  14. Gamma-Ray Burst Precursor Activity as Observed with BATSE

    NASA Technical Reports Server (NTRS)

    Koshut, Thomas M.; Kouveliotou, Chryssa; Paciesas, William S.; vanParadijs, Jan; Pendleton, Geoffrey N.; Briggs, Michael S.; Fishman, Gerald J.; Meegan, Charles A.

    1995-01-01

    Gamma-ray burst time histories often consist of multiple episodes of emission with the count rate dropping to the background level between adjacent episodes. We define precursor activity as any case in which the first episode (referred to as the precursor episode) has a lower peak intensity than that of the remaining emission (referred to as the main episode) and is separated from the remaining burst emission by a background interval that is at least as long as the remaining emission. We find that approx. 3% of the bursts observed with the Burst and Transient Source Experiment (BATSE) on Compton Gamma Ray Observatory (CGRO) satisfy this definition. We present the results of a study of the properties of these events. The spatial distribution of these sources is consistent with that of the larger set of all BATSE gamma-ray bursts: inhomogeneous and isotropic. A correlation between the duration of the precursor emission and the duration of the main episode emission is observed at about the 3 sigma confidence level. We find no meaningful significant correlations between or among any of the other characteristics of the precursor or main episode emission. It appears that the characteristics of the main episode emission are independent of the existence of the precursor emission.

  15. Diacylglycerol kinases activate tobacco NADPH oxidase-dependent oxidative burst in response to cryptogein.

    PubMed

    Cacas, Jean-Luc; Gerbeau-Pissot, Patricia; Fromentin, Jérôme; Cantrel, Catherine; Thomas, Dominique; Jeannette, Emmanuelle; Kalachova, Tetiana; Mongrand, Sébastien; Simon-Plas, Françoise; Ruelland, Eric

    2017-04-01

    Cryptogein is a 10 kDa protein secreted by the oomycete Phytophthora cryptogea that activates defence mechanisms in tobacco plants. Among early signalling events triggered by this microbial-associated molecular pattern is a transient apoplastic oxidative burst which is dependent on the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity of the RESPIRATORY BURST OXIDASE HOMOLOG isoform D (RBOHD). Using radioactive [(33) P]-orthophosphate labelling of tobacco Bright Yellow-2 suspension cells, we here provide in vivo evidence for a rapid accumulation of phosphatidic acid (PA) in response to cryptogein because of the coordinated onset of phosphoinositide-dependent phospholipase C and diacylglycerol kinase (DGK) activities. Both enzyme specific inhibitors and silencing of the phylogenetic cluster III of the tobacco DGK family were found to reduce PA production upon elicitation and to strongly decrease the RBOHD-mediated oxidative burst. Therefore, it appears that PA originating from DGK controls NADPH-oxidase activity. Amongst cluster III DGKs, the expression of DGK5-like was up-regulated in response to cryptogein. Besides DGK5-like is likely to be the main cluster III DGK isoform silenced in one of our mutant lines, making it a strong candidate for the observed response to cryptogein. The relevance of these results is discussed with regard to early signalling lipid-mediated events in plant immunity.

  16. Correlated bursts of activity in the neonatal hippocampus in vivo.

    PubMed

    Leinekugel, Xavier; Khazipov, Rustem; Cannon, Robert; Hirase, Hajime; Ben-Ari, Yehezkel; Buzsáki, György

    2002-06-14

    The behavior of immature cortical networks in vivo remains largely unknown. Using multisite extracellular and patch-clamp recordings, we observed recurrent bursts of synchronized neuronal activity lasting 0.5 to 3 seconds that occurred spontaneously in the hippocampus of freely moving and anesthetized rat pups. The influence of slow rhythms (0.33 and 0.1 hertz) and the contribution of both gamma-aminobutyric acid A-mediated and glutamate receptor-mediated synaptic signals in the generation of hippocampal bursts was reminiscent of giant depolarizing potentials observed in vitro. This earliest pattern, which diversifies during the second postnatal week, could provide correlated activity for immature neurons and may underlie activity-dependent maturation of the hippocampal network.

  17. Random bursts determine dynamics of active filaments.

    PubMed

    Weber, Christoph A; Suzuki, Ryo; Schaller, Volker; Aranson, Igor S; Bausch, Andreas R; Frey, Erwin

    2015-08-25

    Constituents of living or synthetic active matter have access to a local energy supply that serves to keep the system out of thermal equilibrium. The statistical properties of such fluctuating active systems differ from those of their equilibrium counterparts. Using the actin filament gliding assay as a model, we studied how nonthermal distributions emerge in active matter. We found that the basic mechanism involves the interplay between local and random injection of energy, acting as an analog of a thermal heat bath, and nonequilibrium energy dissipation processes associated with sudden jump-like changes in the system's dynamic variables. We show here how such a mechanism leads to a nonthermal distribution of filament curvatures with a non-Gaussian shape. The experimental curvature statistics and filament relaxation dynamics are reproduced quantitatively by stochastic computer simulations and a simple kinetic model.

  18. Random bursts determine dynamics of active filaments

    PubMed Central

    Weber, Christoph A.; Suzuki, Ryo; Schaller, Volker; Aranson, Igor S.; Bausch, Andreas R.; Frey, Erwin

    2015-01-01

    Constituents of living or synthetic active matter have access to a local energy supply that serves to keep the system out of thermal equilibrium. The statistical properties of such fluctuating active systems differ from those of their equilibrium counterparts. Using the actin filament gliding assay as a model, we studied how nonthermal distributions emerge in active matter. We found that the basic mechanism involves the interplay between local and random injection of energy, acting as an analog of a thermal heat bath, and nonequilibrium energy dissipation processes associated with sudden jump-like changes in the system’s dynamic variables. We show here how such a mechanism leads to a nonthermal distribution of filament curvatures with a non-Gaussian shape. The experimental curvature statistics and filament relaxation dynamics are reproduced quantitatively by stochastic computer simulations and a simple kinetic model. PMID:26261319

  19. SGR J1550-5418 Bursts Detected with the Fermi Gamma-Ray Burst Monitor during Its Most Prolific Activity

    NASA Technical Reports Server (NTRS)

    vanderHorst, A. J.; Kouveliotou, C.; Gorgone, N. M.; Kaneko, Y.; Baring, M. G.; Guiriec, S.; Gogus, E,; Granot, J.; Watts, A. L.; Lin, L.; Bhat, P. N.; Bissaldi, E.; Chaplin, V. L.; Finger, M. H.; Gehrels, N.; Gibby, M. H.; Giles, M. M.; Goldstein, A.; Gruber, D.; Harding, A. K.; McEnery, J.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Wilson-Hodge, C.

    2012-01-01

    We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties.We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J15505418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E(sub peak) and the burst fluence and average flux. For the BB+BBfits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature.We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

  20. SGR J1550-5418 BURSTS DETECTED WITH THE FERMI GAMMA-RAY BURST MONITOR DURING ITS MOST PROLIFIC ACTIVITY

    SciTech Connect

    Van der Horst, A. J.; Finger, M. H.; Kouveliotou, C.; Kaneko, Y.; Goegues, E.; Lin, L.; Baring, M. G.; Guiriec, S.; Bhat, P. N.; Chaplin, V. L.; Goldstein, A.; Granot, J.; Watts, A. L.; Bissaldi, E.; Gruber, D.; Gehrels, N.; Harding, A. K.; Gibby, M. H.; Giles, M. M.; and others

    2012-04-20

    We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties. We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J1550-5418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E{sub peak} and the burst fluence and average flux. For the BB+BB fits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high-temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature. We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

  1. Pityriarubins, novel highly selective inhibitors of respiratory burst from cultures of the yeast Malassezia furfur: comparison with the bisindolylmaleimide arcyriarubin A.

    PubMed

    Krämer, Hans-Joachim; Kessler, Dino; Hipler, Ute-Christina; Irlinger, Bernhard; Hort, Wiebke; Bödeker, Rolf-Hasso; Steglich, Wolfgang; Mayser, Peter

    2005-12-01

    Pityriasis versicolor is the most common skin mycosis in humans worldwide. Yeasts of the genus Malassezia, particularly M. furfur, a saprophyte occurring widely on human skin, are generally regarded as the causative agents. M. furfur is able to convert tryptophan into a variety of indole alkaloids, some of them showing biological properties that correlate well with certain clinical features of pityriasis versicolor. This suggests a possible role for these compounds in the pathophysiology of the disease. We here report that the novel pityriarubins A, B and C, isolated from cultures of the yeast, inhibit respiratory burst in human neutrophils, activated by various agents, in a highly selective, unexpected manner. The release of 5-lipoxygenase products after challenge of neutrophils with the calcium ionophore A23187 is also inhibited in a dose-dependent manner. These activities reflect the close structural relationship of pityriarubins to bisindolylmaleimides, which have recently gained great interest as protein kinase inhibitors.

  2. Activation of group I metabotropic glutamate receptors enhances persistent sodium current and rhythmic bursting in main olfactory bulb external tufted cells

    PubMed Central

    Ennis, Matthew

    2013-01-01

    Rhythmically bursting olfactory bulb external tufted (ET) cells are thought to play a key role in synchronizing glomerular network activity to respiratory-driven sensory input. Whereas spontaneous bursting in these cells is intrinsically generated by interplay of several voltage-dependent currents, bursting strength and frequency can be modified by local intrinsic and centrifugal synaptic input. Activation of metabotropic glutamate receptors (mGluRs) engages a calcium-dependent cation current (ICAN) that increases rhythmic bursting, but mGluRs may also modulate intrinsic mechanisms involved in bursting. Here, we used patch-clamp electrophysiology in rat olfactory bulb slices to investigate whether mGluRs modulate two key intrinsic currents involved in ET cell burst initiation: persistent sodium (INaP) and hyperpolarization-activated cation (Ih) currents. Using a BAPTA-based internal solution to block ICAN, we found that the mGluR1/5 agonist DHPG enhanced INaP but did not alter Ih. INaP enhancement consisted of increased current at membrane potentials between −60 and −50 mV and a hyperpolarizing shift in activation threshold. Both effects would be predicted to shorten the interburst interval. In agreement, DHPG modestly depolarized (∼3.5 mV) ET cells and increased burst frequency without effect on other major burst parameters. This increase was inversely proportional to the basal burst rate such that slower ET cells exhibited the largest increases. This may enable ET cells with slow intrinsic burst rates to pace with faster sniff rates. Taken with other findings, these results indicate that multiple neurotransmitter mechanisms are engaged to fine-tune rhythmic ET cell bursting to context- and state-dependent changes in sniffing frequency. PMID:24225539

  3. Nicotinamide Effects Oxidative Burst Activity of Neutrophils in Patients with Poorly Controlled Type 2 Diabetes Mellitus

    PubMed Central

    Samanci, Tülay; Demirel, Gülderen Yanikkaya; Damci, Taner; Ilkova, Hasan

    2004-01-01

    Neutrophil functions are impaired in patients with diabetes mellitus. Bacterial phagocytosis and oxidative burst activity are reduced at high glucose concentrations in diabetic patients. Defects in neutrophil oxidative burst capacity are of multifactorial origin in diabetes mellitus and correlate with glucose levels. It has been reported that neutrophil NADPH oxidase activity is impaired and superoxide production is reduced in diabetic patients with or without any infections. Nicotinamide is a vitamin B3 derivative and a NAD precursor with immunomodulatory effects. In vitro studies demonstrated that nicotinamide increases NAD and NADH content of beta cells. The authors hypothesized that nicotinamide may restore the impaired oxidative burst capacity of neutrophils in diabetic patients by increasing the NADH content as an electron donor and possibly through NADPH oxidase activity of the cell. In order to test the hypothesis, this placebo-controlled and open study was designed to evaluate neutrophil functions in infection-free poorly controlled type 2 diabetic patients as compared to healthy subjects and assess the effects of nicotinamide on neutrophil phagocytosis as well as oxidative burst activity. Thirty patients with type 2 diabetes mellitus were enrolled in the study. Sixteen were females and 14 were males, with a mean age 58 ± 10. All patients were on sulphonylurea treatment and their hemoglobin A1c (HbA1c) levels were above 7.5%. The control group consisted of 10 voluntary healthy subjects. Diabetic and control subjects were not significantly different in terms of age, body mass index (BMI), leucocyte and neutrophil counts, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR), but HbA1c and fasting glucose levels were significantly higher in patients with diabetes mellitus. Phagocytic activity and respiratory burst indexes were measured by flow cytometric analyses as previously described by Rothe and Valet (Methods Enzyml., 233, 539–548

  4. The phosphorylation targets of p47phox, a subunit of the respiratory burst oxidase. Functions of the individual target serines as evaluated by site-directed mutagenesis.

    PubMed Central

    Faust, L R; el Benna, J; Babior, B M; Chanock, S J

    1995-01-01

    The respiratory burst oxidase of phagocytes and B lymphocytes catalyzes the reduction of oxygen to O2- at the expense of NADPH. Dormant in resting cells, the oxidase is activated by exposing the cells to appropriate stimuli. During activation, p47phox, a cytosolic oxidase subunit, becomes extensively phosphorylated on a number of serines located between S303 and S379. To determine whether this phosphorylation is necessary for oxidase activation, we examined phorbol-elicited oxidase activity in EBV-transformed B lymphoblasts deficient in p47phox after transfection with plasmids expressing various S-->A mutants of p47phox. The mutant containing S-->A mutations involving all serines between S303 and S379 [S(303-379)A] was not phosphorylated, did not translocate to plasma membrane during activation and was almost devoid of function. As to individual serines, S379 was of special interest because (a) p47 phox S379 was phosphorylated in phorbol-activated lymphoblasts expressing wild-type p47phox, and (b) p47phox S379A failed to translocate to the membrane, and was as functionless as p47phox S(303-379)A; other single S-->A mutations had little effect on oxidase activity. These findings suggest that the phosphorylation of S379 may be important for oxidase activation in whole cells. Images PMID:7657821

  5. May the variable magnetic field and pulse red light induce synergy effects in respiratory burst of neutrophils in vitro?

    NASA Astrophysics Data System (ADS)

    Nawrocka-Bogusz, H.; Jaroszyk, F.

    2011-12-01

    We investigated the effect of the red light (R) (630 nm), magnetic field (MF) and magnetic field combined with the red light (MF+R) upon reactive oxygen species (ROS) production by neutrophils in vitro. The object of the research was hydrogen peroxide (H2O2) formation during neutrophils respiratory burst or within steady-state. Blood from healthy volunteers was used for the purpose of the study. Flow cytometry method, using transformation of DCFH-DA (2'7'-dichlorofluorescin diacetate) to the fluorescent DCF (2'7'-dichlorofluorescin), was used for estimation of hydrogen peroxide production. The variable magnetic field of ELF range of the mean induction equals 26.7(μT), the red light at the energy density of 1.17(J/cm2) and their combination were applied for 30 minutes each. The fundamental frequency of pulses was 180÷ 195 Hz. A statistically significant decrease of H2O2 production by neutrophils was observed. The level of the decrease was in the range of 10-30% and was dependent on the kind of applied physical factors and whether neutrophils were stimulated or not. The observation showed that the variable magnetic field combined with red light do not induce the synergy effect.

  6. Eros is a novel transmembrane protein that controls the phagocyte respiratory burst and is essential for innate immunity

    PubMed Central

    Thomas, David C.; Clare, Simon; Sowerby, John M.; Juss, Jatinder K.; Goulding, David A.; van der Weyden, Louise; Prakash, Ananth; Harcourt, Katherine; Mukhopadhyay, Subhankar; Antrobus, Robin; Bateman, Alex

    2017-01-01

    The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91phox and p22phox subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene bc017643, and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91phox and p22phox. Consequently, Eros-deficient mice quickly succumb to infection. Eros also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. Eros is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense. PMID:28351984

  7. Origin of the phagocytic respiratory burst and its role in gut epithelial phagocytosis in a basal chordate.

    PubMed

    Yang, Ping; Huang, Shengfeng; Yan, Xinyu; Huang, Guangrui; Dong, Xiangru; Zheng, Tingting; Yuan, Dongjuan; Wang, Ruihua; Li, Rui; Tan, Ying; Xu, Anlong

    2014-05-01

    The vertebrate phagocytic respiratory burst (PRB) is a highly specific and efficient mechanism for reactive oxygen species (ROS) production. This mechanism is mediated by NADPH oxidase 2 (NOX2) and used by vertebrate phagocytic leukocytes to destroy internalized microbes. Here we demonstrate the presence of the PRB in a basal chordate, the amphioxus Branchiostoma belcheri tsingtauense (bbt). We show that using the antioxidant NAC to scavenge the production of ROS significantly decreased the survival rates of infected amphioxus, indicating that ROS are indispensable for efficient antibacterial responses. Amphioxus NOX enzymes and cytosolic factors were found to colocalize in the epithelial cells of the gill, intestine, and hepatic cecum and could be upregulated after exposure to microbial pathogens. The ROS production in epithelial cell lysates could be reconstructed by supplementing recombinant cytosolic factors, including bbt-p47phox, bbt-p67phox, bbt-p47phox, and bbt-Rac; the restored ROS production could be inhibited by anti-bbt-NOX2 and anti-bbt-p67phox antibodies. We also reveal that the gut epithelial lining cells of the amphioxus are competent at bacterial phagocytosis, and there is evidence that the PRB machinery could participate in the initiation of this phagocytic process. In conclusion, we report the presence of the classical PRB machinery in nonvertebrates and provide the first evidence for the possible role of PRB in epithelial cell immunity and phagocytosis.

  8. Eros is a novel transmembrane protein that controls the phagocyte respiratory burst and is essential for innate immunity.

    PubMed

    Thomas, David C; Clare, Simon; Sowerby, John M; Pardo, Mercedes; Juss, Jatinder K; Goulding, David A; van der Weyden, Louise; Storisteanu, Daniel; Prakash, Ananth; Espéli, Marion; Flint, Shaun; Lee, James C; Hoenderdos, Kim; Kane, Leanne; Harcourt, Katherine; Mukhopadhyay, Subhankar; Umrania, Yagnesh; Antrobus, Robin; Nathan, James A; Adams, David J; Bateman, Alex; Choudhary, Jyoti S; Lyons, Paul A; Condliffe, Alison M; Chilvers, Edwin R; Dougan, Gordon; Smith, Kenneth G C

    2017-04-03

    The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91phox and p22phox subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene bc017643, and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91phox and p22phox Consequently, Eros-deficient mice quickly succumb to infection. Eros also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. Eros is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense.

  9. Diet supplementation of Pediococcus pentosaceus in cobia (Rachycentron canadum) enhances growth rate, respiratory burst and resistance against photobacteriosis.

    PubMed

    Xing, Chen-Fu; Hu, Hung-Hsi; Huang, Jian-Bin; Fang, Han-Chun; Kai, Yu-Hsuan; Wu, Yu-Chi; Chi, Shau-Chi

    2013-10-01

    Cobia (Rachycentron canadum) is an economically important fish species for aquaculture in tropical and sub-tropical areas. Cobia aquaculture industry has severely damaged due to photobacteriosis caused by Photobacterium damselae subsp. piscicida (Pdp), especially in Taiwan. Antibiotics and vaccines have been applied to control Pdp infection, but the efficacy has been inconsistent. One species of lactic acid bacteria, Pediococcus pentosaceus strain 4012 (LAB 4012), was isolated from the intestine of adult cobia, and its culture supernatant can effectively inhibit Pdp growth in vitro. The acidic pH derived from metabolic acids in LAB culture supernatant was demonstrated to be an important factor for the suppression. After a 2-week feeding of LAB 4012, the growth rate of the fed cobia was 12% higher than that of the non-fed group, and the relative percentage of survival (RPS) of the fed cobia was found to be 74.4 in Pdp immersion challenge. In addition, the respiratory burst (RB) of peripheral blood leukocytes (PBL) in the LAB 4012-fed group was significantly higher than that of the non-fed group. Although feeding LAB 4012 did not improve specific antibody response in cobia after immunization with Pdp vaccine, it still significantly raised the survival rate by 22% over that of the non-fed group after Pdp immersion challenge. Judging by the quick induction of high protection against Pdp infection and promotion of growth in larvae, LAB 4012 was considered to be a viable probiotic for cobia aquaculture.

  10. Effects of heat stress on respiratory burst, oxidative damage and SERPINH1 (HSP47) mRNA expression in rainbow trout Oncorhynchus mykiss.

    PubMed

    Wang, Yanni; Liu, Zhe; Li, Zhen; Shi, Haina; Kang, Yujun; Wang, Jianfu; Huang, Jinqiang; Jiang, Li

    2016-04-01

    For rainbow trout Oncorhynchus mykiss, high temperature is a major abiotic stress that limits its growth and productivity. In this study, spleen macrophage respiratory burst (RB), serum superoxide dismutase (SOD), serum malondialdehyde (MDA) and mRNA expression of the SERPINH1 (HSP47) gene in different tissues (liver, spleen, head kidney and heart) were measured in unstressed (18 °C) and heat-stressed (25 °C) fish. Spleen macrophage RB activity, serum SOD activity and MDA content all increased significantly (P < 0.05) during heat shock, and peaked at 8, 12 and 4 h, respectively. SERPINH1 mRNA expression responded in a time- and tissue-specific manner to heat stress, which was mainly reflected in the significant up-regulation in all tissues (P < 0.05) and greater expression in the liver than the other tissues (P < 0.05). During the heat-shock recovery period, the MDA content returned to the unstressed level. These results indicate that heat shock causes cell injury, induces oxidative damage and promotes SERPINH1 mRNA expression, which plays an important protective function during heat stress in O. mykiss. In practice, close attention should be given to temperature changes in O. mykiss production to reduce the effects of high temperature.

  11. Effects of corticotropin releasing factor on spontaneous burst activity in the piriform-amygdala complex of in vitro brain preparations from newborn rats.

    PubMed

    Fujii, Tomoko; Onimaru, Hiroshi; Homma, Ikuo

    2011-10-01

    The amygdala is an important higher regulatory center of the autonomic nervous system, involved in respiratory and cardiovascular control, and it also plays a role in the formation of emotions. Corticotropin-releasing factor (CRF) is a neuropeptide involved in stress responses. We have examined the effects of CRF on the spontaneous burst activity in the piriform-amygdala complex of rat brain preparations in vitro. Limbic-brainstem-spinal cord preparations of 0- to 1-day-old Wistar rats were isolated under deep ether anesthesia, and were superperfused in a modified Krebs solution. Bath application of 50nM CRF substantially increased the frequency of burst activity in the piriform-amygdala complex, whereas this polypeptide exerted only minor effects on C4 inspiratory activity. The excitatory effect of CRF on the amygdala burst was effectively blocked by the CRF1 antagonist, antalarmin, but not the CRF2 antagonist, astressin-2B, suggesting that CRF1 mediated the excitatory effect. The spatio-temporal pattern of the burst activity according to optical recordings was basically identical to the controls; the burst activity initially appeared in the piriform cortex and then propagated to the amygdala. The present experimental model could be useful for the study of role of the limbic system, including the amygdala, in stress responses.

  12. Central respiratory effects on motor nerve activities after organophosphate exposure in a working heart brainstem preparation of the rat.

    PubMed

    Klein-Rodewald, Tanja; Seeger, Thomas; Dutschmann, Mathias; Worek, Franz; Mörschel, Michael

    2011-09-25

    The impact of organophosphorus compound (OP) intoxication on the activity of central respiratory circuitry, causing acetylcholinesterase (AChE) inhibition and accumulation of acetylcholine in the respiratory brainstem circuits, is not understood. We investigated the central effect of the OP Crotylsarin (CRS) on respiratory network activity using the working heart brainstem preparation, which specifically allows for the analysis of central drug effects without changes in brainstem oxygenation possibly caused by drug effects on peripheral cardio-respiratory activity. Respiratory network activity was determined from phrenic and hypoglossal or vagal nerve activities (PNA, HNA, VNA). To investigate combined central and peripheral CRS effects hypo-perfusion was used mimicking additional peripheral cardiovascular collapse. Systemic CRS application induced a brief central apnea and complete AChE-inhibition in the brainstem. Subsequently, respiration was characterised by highly significant reduced PNA minute activity, while HNA showed expiratory related extra bursting indicative for activation of un-specified oro-pharyngeal behaviour. During hypo-perfusion CRS induced significantly prolonged apnoea. In all experiments respiratory activity fully recovered after 1h. We conclude that CRS mediated AChE inhibition causes only transient central breathing disturbance. Apparently intrinsic brainstem mechanisms can compensate for cholinergic over activation. Nevertheless, combination of hypo-perfusion and CRS exposure evoke the characteristic breathing arrests associated with OP poisoning.

  13. Decrement of uterine myometrial burst duration as a correlate to active labor: A Hilbert phase approach

    PubMed Central

    Govindan, Rathinaswamy B.; Vairavan, Srinivasan; Furdea, Adrian; Murphy, Pam; Preissl, Hubert; Eswaran, Hari

    2011-01-01

    We propose a novel approach based on Hilbert phase to identify the burst in the uterine myometrial activity. We apply this approach to 24 serial magnetomyographic signals recorded from four pregnant women using a 151 SQUID array system. The bursts identified with this approach are evaluated for duration and are correlated with the gestational age. In all four subjects, we find a decrease in the duration of burst as the subject approaches active labor. As was shown in animal studies, this result indicates a faster conduction time between the muscle cells which activate a larger number of muscle units in a synchronous manner. PMID:21096231

  14. Nitric oxide changes its role as a modulator of respiratory motor activity during development in the bullfrog (Rana catesbeiana).

    PubMed

    Hedrick, Michael S; Chen, Anna K; Jessop, Kristy L

    2005-10-01

    Nitric oxide (NO) is a unique chemical messenger that has been shown to play a role in the modulation of breathing in amphibians and other vertebrates. In the post-metamorphic tadpole and adult amphibian brainstem, NO, acting via the neuronal isoform of nitric oxide synthase (nNOS), is excitatory to the generation of lung burst activity. In this study, we examine the modulation of breathing by NO during development of the amphibian brainstem. Isolated brainstem preparations from pre-metamorphic and late-stage post-metamorphic tadpoles (Rana catesbeiana) were used to determine the role of NO in modulating central respiratory neural activity. Respiratory neural activity was monitored with suction electrodes recording extracellular activity of cranial nerve rootlets that innervate respiratory musculature. Brainstems were superfused with an artificial cerebrospinal fluid (aCSF) at 20-22 degrees C containing l-nitroarginine (l-NA; 1-10 mM), a non-selective NOS inhibitor. In pre-metamorphic tadpoles, l-NA increased fictive gill ventilation frequency and amplitude, and increased lung burst frequency. By contrast, l-NA applied to the post-metamorphic tadpole brainstem had little effect on fictive buccal activity, but significantly decreased lung burst frequency and the frequency of lung burst episodes. These data indicate that early in development, NO provides a tonic inhibitory input to gill and lung burst activity, but as development progresses, NO provides an excitatory input to lung ventilation. This changing role for NO coincides with the shift in importance in the different respiratory modes during development in amphibians; that is, pre-metamorphic tadpoles rely predominantly on gill ventilation whereas post-metamorphic tadpoles have lost the gills and are obligate air-breathers primarily using lungs for gas exchange. We hypothesize that NO provides a tonic input to the respiratory CPG during development and this changing role reflects the modulatory influence of NO

  15. Hypoglossal Neuropathology and Respiratory Activity in Pompe Mice

    PubMed Central

    Sandhu, Milapjit S.; Elmallah, Mai K.; Falk, Darin J.; Lane, Michael A.; Reier, Paul J.; Byrne, Barry J.; Fuller, David D.

    2011-01-01

    Pompe disease is a lysosomal storage disorder associated with systemic deficiency of acid α-glucosidase (GAA). Respiratory-related problems in Pompe disease include hypoventilation and upper airway dysfunction. Although these problems have generally been attributed to muscular pathology, recent work has highlighted the potential role of central nervous system (CNS) neuropathology in Pompe motor deficiencies. We used a murine model of Pompe disease to test the hypothesis that systemic GAA deficiency is associated with hypoglossal (XII) motoneuron pathology and altered XII motor output during breathing. Brainstem tissue was harvested from adult Gaa−/− mice and the periodic acid Schiff method was used to examine neuronal glycogen accumulation. Semi-thin (2 μm) plastic sections showed widespread medullary neuropathology with extensive cytoplasmic glycogen accumulation in XII motoneuron soma. We next recorded efferent XII bursting in anesthetized and ventilated Gaa−/− and B6/129 mice both before and after bilateral vagotomy. The coefficient of variation of respiratory cycle duration was greater in Gaa−/− compared to B6/129 mice (p < 0.01). Vagotomy caused a robust increase in XII inspiratory burst amplitude in B6/129 mice (239 ± 44% baseline; p < 0.01) but had little impact on burst amplitude in Gaa−/− mice (130 ± 23% baseline; p > 0.05). We conclude that CNS GAA deficiency results in substantial glycogen accumulation in XII motoneuron cell bodies and altered XII motor output. Therapeutic strategies targeting the CNS may be required to fully correct respiratory-related deficits in Pompe disease. PMID:21747768

  16. Effects of raspberry fruit extracts and ellagic acid on respiratory burst in murine macrophages.

    PubMed

    Raudone, Lina; Bobinaite, Ramune; Janulis, Valdimaras; Viskelis, Pranas; Trumbeckaite, Sonata

    2014-06-01

    The mechanism of action of polyphenolic compounds is attributed to their antioxidant, anti-inflammatory, and anti-proliferative properties and their effects on subcellular signal transduction, cell cycle impairment and apoptosis. A raspberry (Rubus idaeus L.) fruit extract contains various antioxidant active compounds, particularly ellagic acid (EA); however the exact intracellular mechanism of their action is not fully understood. The aim of the study was to evaluate the antioxidant effect of raspberry extracts, and that of ellagic acid by assessment of the production of the reactive oxygen species (ROS) by murine macrophage J774 cells. Raspberry extracts and their active compound EA did not affect or had very minor effects on cell viability. No significant difference in the ROS generation in arachidonic acid stimulated macrophages was determined for raspberry extracts and EA whereas in the phorbol-12 myristate-13 acetate model ROS generation was significantly (p < 0.05) reduced. Our observation that raspberry pomace extracts in vitro reduce ROS production in a J774 macrophage culture suggests that raspberry extract and ellagic acid mediated antioxidant effects may be due to the regulation of NADPH oxidase activity.

  17. Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

    PubMed Central

    Persson, Karin; Rekling, Jens C

    2011-01-01

    Abstract The brainstem contains rhythm and pattern forming circuits, which drive cranial and spinal motor pools to produce respiratory and other motor patterns. Here we used calcium imaging combined with nerve recordings in newborn mice to reveal spontaneous population activity in the ventral brainstem and in the facial nucleus. In Fluo-8 AM loaded brainstem–spinal cord preparations, respiratory activity on cervical nerves was synchronized with calcium signals at the ventrolateral brainstem surface. Individual ventrolateral neurons at the level of the parafacial respiratory group showed perfect or partial synchrony with respiratory nerve bursts. In brainstem–spinal cord preparations, cut at the level of the mid-facial nucleus, calcium signals were recorded in the dorsal, lateral and medial facial subnuclei during respiratory activity. Strong activity initiated in the dorsal subnucleus, followed by activity in lateral and medial subnuclei. Whole-cell recordings from facial motoneurons showed weak respiratory drives, and electrical field potential recordings confirmed respiratory drive to particularly the dorsal and lateral subnuclei. Putative facial premotoneurons showed respiratory-related calcium signals, and were predominantly located dorsomedial to the facial nucleus. A novel motor activity on facial, cervical and thoracic nerves was synchronized with calcium signals at the ventromedial brainstem extending from the level of the facial nucleus to the medulla–spinal cord border. Cervical dorsal root stimulation induced similar ventromedial activity. The medial facial subnucleus showed calcium signals synchronized with this novel motor activity on cervical nerves, and cervical dorsal root stimulation induced similar medial facial subnucleus activity. In conclusion, the dorsal and lateral facial subnuclei are strongly respiratory-modulated, and the brainstem contains a novel pattern forming circuit that drives the medial facial subnucleus and cervical motor

  18. Emergence of spatially heterogeneous burst suppression in a neural field model of electrocortical activity

    PubMed Central

    Bojak, Ingo; Stoyanov, Zhivko V.; Liley, David T. J.

    2015-01-01

    Burst suppression in the electroencephalogram (EEG) is a well-described phenomenon that occurs during deep anesthesia, as well as in a variety of congenital and acquired brain insults. Classically it is thought of as spatially synchronous, quasi-periodic bursts of high amplitude EEG separated by low amplitude activity. However, its characterization as a “global brain state” has been challenged by recent results obtained with intracranial electrocortigraphy. Not only does it appear that burst suppression activity is highly asynchronous across cortex, but also that it may occur in isolated regions of circumscribed spatial extent. Here we outline a realistic neural field model for burst suppression by adding a slow process of synaptic resource depletion and recovery, which is able to reproduce qualitatively the empirically observed features during general anesthesia at the whole cortex level. Simulations reveal heterogeneous bursting over the model cortex and complex spatiotemporal dynamics during simulated anesthetic action, and provide forward predictions of neuroimaging signals for subsequent empirical comparisons and more detailed characterization. Because burst suppression corresponds to a dynamical end-point of brain activity, theoretically accounting for its spatiotemporal emergence will vitally contribute to efforts aimed at clarifying whether a common physiological trajectory is induced by the actions of general anesthetic agents. We have taken a first step in this direction by showing that a neural field model can qualitatively match recent experimental data that indicate spatial differentiation of burst suppression activity across cortex. PMID:25767438

  19. Gamma-ray bursts, QSOs and active galaxies.

    PubMed

    Burbidge, Geoffrey

    2007-05-15

    The similarity of the absorption spectra of gamma-ray burst (GRB) sources or afterglows with the absorption spectra of quasars (QSOs) suggests that QSOs and GRB sources are very closely related. Since most people believe that the redshifts of QSOs are of cosmological origin, it is natural to assume that GRBs or their afterglows also have cosmological redshifts. For some years a few of us have argued that there is much optical evidence suggesting a very different model for QSOs, in which their redshifts have a non-cosmological origin, and are ejected from low-redshift active galaxies. In this paper I extend these ideas to GRBs. In 2003, Burbidge (Burbidge 2003 Astrophys. J. 183, 112-120) showed that the redshift periodicity in the spectra of QSOs appears in the redshift of GRBs. This in turn means that both the QSOs and the GRB sources are similar objects ejected from comparatively low-redshift active galaxies. It is now clear that many of the GRBs of low redshift do appear in, or very near, active galaxies.A new and powerful result supporting this hypothesis has been produced by Prochter et al. (Prochter et al. 2006 Astrophys. J. Lett. 648, L93-L96). They show that in a survey for strong MgII absorption systems along the sightlines to long-duration GRBs, nearly every sightline shows at least one absorber. If the absorbers are intervening clouds or galaxies, only a small fraction should show absorption of this kind. The number found by Prochter et al. is four times higher than that normally found for the MgII absorption spectra of QSOs. They believe that this result is inconsistent with the intervening hypothesis and would require a statistical fluctuation greater than 99.1% probability. This is what we expect if the absorption is intrinsic to the GRBs and the redshifts are not associated with their distances. In this case, the absorption must be associated with gas ejected from the QSO. This in turn implies that the GRBs actually originate in comparatively low

  20. Characterization of human erythroid burst-promoting activity derived from bone marrow conditioned media

    SciTech Connect

    Porter, P.N.; Ogawa, M.

    1982-06-01

    Bone marrow conditioned media (BMCM) increases burst number and the incorporation of /sup 59/Fe into heme by bursts when peripheral blood or bone marrow cells are cultured at limiting serum concentrations. Burst-promoting activity (BPA) has now been purified approximately 300-fold from this source by ion-exchange chromatography on DEAE-Sephadex and absorption chromatography on hydroxyapatite agarose gel. Marrow BPA increased burst number and hemoglobin (Hb) synthesis in a dose-dependent manner. A larger increase in Hb synthesis than in burst number was consistently observed, which was probably a consequence of the increase in the number of cells per burst that occurs in the presence of BPA. The role of BPA in culture could be distinguished from erythropoietin (Ep), since no bursts grew in the absence of Ep, whether or not BPA was present, and since it had no effect on the growth of erythroid colonies scored at day 5 of culture. Our purified fraction did not support the growth of CFU-C in culture. Activity was stable at temperatures of 70 degrees C or lower for 10 min; exposure to 80 degrees C resulted in approximately 50% loss of activity. BPA was completely inactivated by treatment at 100 degrees C for 10 min. Thus, human bone marrow cells produce a heat-sensitive factor that specifically promotes the growth of early erythroid progenitors in culture.

  1. Active learning of respiratory physiology improves performance on respiratory physiology examinations.

    PubMed

    Rao, S P; DiCarlo, S E

    2001-12-01

    Active involvement in the learning process has been suggested to enhance creative thinking, judgement, interpretation, and problem-solving skills. Therefore, educators are encouraged to create an active-learning environment by incorporating active-learning strategies into the class. However, there is very little documentation of the effectiveness of active-learning strategies. Furthermore, faculty are often reluctant to incorporate new strategies without documentation of the effectiveness of these strategies. To address this concern, we compared the performance of two individual classes on an identical respiratory physiology examination. One class was taught respiratory physiology using active-learning strategies. The other class was taught respiratory physiology using the traditional lecture format. The results document that students who learned using active-learning strategies did significantly better (P < 0.05) on the respiratory physiology examination than students who learned by the traditional lecture format (61 +/- 2.2 vs. 86 +/- 1.0). Thus, by actively involving students in the learning process, academic performance is enhanced.

  2. Activity of respiratory system during laser irradiation of brain structures

    NASA Astrophysics Data System (ADS)

    Merkulova, N. A.; Sergeyeva, L. I.

    1984-06-01

    The performance of one of the principal links of the respiratory system, the respiratory center, was studied as a function of the exposure of the medulla oblongata and the sensomotor zone of the cerebral hemisphere cortex to low level laser irradiation in the red wavelength of the spectrum. Experiments were done on white rats under barbital anesthesia. Under such conditions a substantial effect was observed on the activity of the respiratory center. Laser light may display activating or inhibitory influences, in some cases the bilateral symmetry of the activity of the respiratory center is affected indicating deep changes in the integrative mechanism of the functioning of the right and left sides of the hemispheres. The laser beam effect depends on many factors: specific light properties, duration of the exposure, repetition of exposures, initial functional state of the CNS, etc.

  3. [Study of cardiac, respiratory, and motor activity in rat fetuses].

    PubMed

    Timofeeva, O P; Vdovichenko, N D

    2009-01-01

    Development of the cardiac, respiratory, and motor activity was studied in rat fetuses with preserved placenta circulation was studied at the 16th, 18th, and 20th gestation days. The presence of three main movement types has been found: complexes of generalization activity, local movements, and jerks. In development of respiratory function, there is observed a gradual transition from individual inspirations to series of respiratory movements and then to formation of periodic respiration episodes. At the studied period, the heart rate has been found to increase. The existence of the slow-wave modulations it the heart rate with a period of 20-40 s has been revealed. Analysis of interrelations between the respiratory and motor systems has shown that in the 16-day fetuses, each respiratory movement is accompanied by extensor jerk. By the 20th days of embryonic development (E20), uncoupling of the respiratory and motor activities occurs. Comparison of the activity observed in the cardiac and somatomotor systems has shown that at E16, the cardiac rhythm fluctuations do not depend on the motor excitation jerks. In the 18-day fetuses, brief slowing down (decelerations) of the cardiac rhythm appeared during the motor activity jerks, whereas at E20, on the contrary, an increase of frequency (accelerations) of the cardiac rhythm occurred.

  4. Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

    NASA Technical Reports Server (NTRS)

    Noohi, Fatemeh; Kinnaird, Catherine; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar; Seidler, Rachael

    2014-01-01

    The aim of the current study was to characterize the brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit saccular Vestibular Evoked Myogenic Potentials (VEMP) (Colebatch & Halmagyi 1992; Colebatch et al. 1994). Some researchers have reported that airconducted skull tap elicits both saccular and utricle VEMPs, while being faster and less irritating for the subjects (Curthoys et al. 2009, Wackym et al., 2012). However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying the vestibular disorders related to otolith deficits. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, pre and post central gyri, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation (Bottini et al., 1994; Dieterich et al., 2003; Emri et al., 2003; Schlindwein et al., 2008; Janzen et al., 2008). Here we hypothesized that the skull tap elicits the similar pattern of cortical activity as the auditory tone burst. Subjects put on a set of MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in supine position, with eyes closed. All subjects received both forms of the stimulation, however, the order of stimulation with auditory tone burst and air-conducted skull tap was counterbalanced across subjects. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular cortex, resulting in vestibular response (Halmagyi et al., 1995). Auditory tone bursts were also delivered for comparison. To validate

  5. Light controls shoot meristem organogenic activity and leaf primordia growth during bud burst in Rosa sp.

    PubMed

    Girault, Tiffanie; Bergougnoux, Veronique; Combes, Didier; Viemont, Jean-Daniel; Leduc, Nathalie

    2008-11-01

    Light controls bud burst in many plants, which subsequently affects their architecture. Nevertheless, very little is known about this photomorphogenic process. This study ascertains the effects of light on bud burst and on two of its components, i.e. growth of preformed leaves and meristem organogenesis in six cultivars from three Rosa species (R. hybrida L., R. chinensis L., R. wichurana L.). Defoliated plants were severed above the third basal bud and exposed, either to darkness or to different intensities of white light, to blue, red or to FR, at constant temperature. Bud bursting was inhibited in darkness in the six cultivars of Rosa, but not in Arabidopsis, tomato and poplar plants under the same condition. In all Rosa cultivars, bud burst, growth of preformed leaves and meristem organogenesis were triggered by blue and red lights, and extended by increasing light intensities. FR was inhibitory of bud burst. Partial shading experiments demonstrated that bud and not stem was the active site for light perception in bud burst.

  6. The 2006-2007 Active Phase Of Anomalous X-Ray Pulsar 4U 0142+61: Radiative and Timing Changes, Bursts, and Burst Spectral Features

    NASA Technical Reports Server (NTRS)

    Gavril, Fotis P.; Dib, Rim; Kaspi, Victoria M.

    2009-01-01

    After at least 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months and included six X-ray bursts as well as many changes in the persistent X-ray emission. The bursts, the first seen from this AXP in >11 years of Rossi X-ray Timing Explorer monitoring, all occurred in the interval between 2006 April 6 and 2007 February 7. The burst durations ranged from 8-3x10(exp 3)s. The first five burst spectra are well modeled by blackbodies, with temperatures kT approx. 2 - 6 keV. However, the sixth burst had a complicated spectrum that is well characterized by a blackbody plus three emission features whose amplitude varied throughout the burst. The most prominent feature was at 14.0 keV. Upon entry into the active phase the pulsar showed a significant change in pulse morphology and a likely timing glitch. The glitch had a total frequency jump of (1.9+/-0.4)x10(exp -7) Hz, which recovered with a decay time of 17+/-2 days by more than the initial jump, implying a net spin-down of the pulsar. We discuss these events in the context of the magnetar model.

  7. Effects of physical activity on exercise tests and respiratory function

    PubMed Central

    Cheng, Y; Macera, C; Addy, C; Sy, F; Wieland, D; Blair, S

    2003-01-01

    Background: Exercise is an important component of pulmonary rehabilitation for patients with chronic lung disease. Objective: To explore the role of physical activity in maintaining cardiac and respiratory function in healthy people. Methods: Cardiorespiratory fitness was measured by a maximal treadmill test (MTT), and respiratory function was tested by spirometry. The cross sectional study included data from 24 536 healthy persons who were examined at the Cooper Clinic between 1971 and 1995; the longitudinal study included data from 5707 healthy persons who had an initial visit between 1971 and 1995 and a subsequent visit during the next five years. All participants were aged 25–55 years and completed a cardiorespiratory test and a medical questionnaire. Results: In the cross sectional study, after controlling for covariates, being active and not being a recent smoker were associated with better cardiorespiratory fitness and respiratory function in both men and women. In the follow up study, persons who remained or became active had better MTT than persons who remained or became sedentary. Men who remained active had higher forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) than the other groups. Smoking was related to lower cardiorespiratory fitness and respiratory function. Conclusions: Physical activity and non-smoking or smoking cessation is associated with maintenance of cardiorespiratory fitness. Change in physical activity habits is associated with change in cardiorespiratory fitness, but respiratory function contributed little to this association during a five year follow up. PMID:14665592

  8. Nonuniform spatial patterns of respiratory activity within biofilms during disinfection.

    PubMed Central

    Huang, C T; Yu, F P; McFeters, G A; Stewart, P S

    1995-01-01

    Fluorescent stains in conjunction with cryoembedding and image analysis were applied to demonstrate spatial gradients in respiratory activity within bacterial biofilms during disinfection with monochloramine. Biofilms of Klebsiella pneumoniae and Pseudomonas aeruginosa grown together on stainless steel surfaces in continuous-flow annular reactors were treated with 2 mg of monochloramine per liter (influent concentration) for 2 h. Relatively little biofilm removal occurred as evidenced by total cell direct counts. Plate counts (of both species summed) indicated an average 1.3-log decrease after exposure to 2 mg of monochloramine per liter. The fluorogenic redox indicator 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and the DNA stain 4',6-diamidino-2-phenylindole (DAPI) were used to differentiate respiring and nonrespiring cells in biofilms. Epifluorescence micrographs of frozen biofilm cross sections clearly revealed gradients of respiratory activity within biofilms in response to monochloramine treatment. These gradients in specific respiratory activity were quantified by calculating the ratio of CTC and DAPI intensities measured by image analysis. Cells near the biofilm-bulk fluid interface lost respiratory activity first. After 2 h of biocide treatment, greater respiratory activity persisted deep in the biofilm than near the biofilm-bulk fluid interface. PMID:7793945

  9. Strategies to Maximize Burst Lengths in Rhythmic Anti-Phase Activity of Networks with Reciprocal Inhibition

    NASA Astrophysics Data System (ADS)

    Bose, Amitabha; Rubin, Jonathan E.

    2015-06-01

    We consider repetitive activity patterns in which a pair of oscillators take turns becoming active, motivated by anti-phase bursting activity in neuronal networks. In our framework, when one unit is active, it inhibits the other, as occurs with inhibitory synaptic coupling of neurons; when the inhibition is strong enough, the inhibited unit is prevented from activating. We assume that the coupling resources available to each oscillator are constrained and allow each unit to select the amount of input that it provides to the other each time that it activates. In this setting, we investigate the strategies that each oscillator should utilize in order to maximize the number of spikes it can fire (or equivalently the amount of time it is active), corresponding to a burst of spikes in a neuron, before the other unit takes over. We derive a one-dimensional map whose fixed points correspond to periodic anti-phase bursting solutions. We introduce a novel numerical method to obtain the graph of this map and we extend the analysis to select solutions that achieve consistency between coupling resource use and recovery. Our analysis shows that corresponding to each fixed point of the map, there is actually an infinite number of related strategies that yield the same number of spikes per burst.

  10. Activation Counter Using Liquid Light-Guide for Dosimetry of Neutron Burst

    NASA Astrophysics Data System (ADS)

    Hayashi, Mitsunobu; Kawarabayashi, Jun; Tomita, Hideki; Asai, Keisuke; Maeda, Shigetaka; Tsuji, Hiroki; Iguchi, Tetsuo

    2009-08-01

    A novel activation counter is proposed using a liquid light-guide (LLG) and a suitable group of activation foils for dosimetry of neutron burst. The LLG that works as a position sensitive radiation detector, has been covered with appropriate activation materials whose threshold energies are different to each other, with a distance of a few tens of cm between them. Since the induced activities of activation foils irradiated by neutrons are detected independently by the LLG, the neutron energy distribution and its flux can be derived from the activities and their neutron cross-sections by numerical de-convolution calculation. The proposed activation counter would be suitable for the dosimetry of intense neutron burst including fast neutrons because the LLG and the activation foils have a high tolerance for radiation damage. We have designed the system configuration of the proposed activation counter. The preliminary results of the responses due to thermal and fast neutrons have been obtained successfully.

  11. The 2006-2007 Active Phase of Anomalous X-Ray Pulsar 4U 0142+61: Radiative and Timing Changes, Bursts,and Burst Spectral Features

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Dib, Rim; Kaspi, Victoria M.

    2011-01-01

    After at least 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months and included six X-ray bursts as well as many changes in the persistent X-ray emission. The bursts, the first seen from this AXP in > 11 years of Rossi X-ray Timing Explorer monitoring, all occurred in the interval between 2006 April 6 and 2007 February 7. The burst durations ranged from 0.4 - 1.8 x 10(exp 3) s. The first five burst spectra are well modeled by blackbodies, with temperatures kT approx 2 - 9 keV. However, the sixth burst had a complicated spectrum that is well characterized by a blackbody plus two emission features whose amplitude varied throughout the burst. The most prominent feature was at 14.0 keV. Upon entry into the active phase the pulsar showed a significant change in pulse morphology and a likely timing glitch. The glitch had a total frequency jump of (1.9+/-0.4) x 10(exp -7) Hz, which recovered with a decay time of 17+/-2 days by more than the initial jump, implying a net spin-down of the pulsar. Within the framework of the magnetar model, the net spin-down of the star could be explained by regions of the superfluid that rotate. slower than the rest. The bursts, flux enhancements, and pulse morphology changes can be explained as arising from crustal deformations due to stresses imposed by the highly twisted internal magnetic field. However, unlike other AXP outbursts, we cannot account for a major twist being implanted in the magnetosphere.

  12. Fast activating voltage- and calcium-dependent potassium (BK) conductance promotes bursting in pituitary cells: a dynamic clamp study

    PubMed Central

    Tabak, Joël; Tomaiuolo, Maurizio; Gonzalez-Iglesias, Arturo E.; Milescu, Lorin S.; Bertram, Richard

    2011-01-01

    The electrical activity pattern of endocrine pituitary cells regulates their basal secretion level. Rat somatotrophs and lactotrophs exhibit spontaneous bursting and have high basal levels of hormone secretion, while gonadotrophs exhibit spontaneous spiking and have low basal hormone secretion. It has been proposed that the difference in electrical activity between bursting somatotrophs and spiking gonadotrophs is due to the presence of large conductance potassium (BK) channels on somatotrophs but not on gonadotrophs. This is one example where the role of an ion channel type may be clearly established. We demonstrate here that BK channels indeed promote bursting activity in pituitary cells. Blocking BK channels in bursting lacto-somatotroph GH4C1 cells changes their firing activity to spiking, while further adding an artificial BK conductance via dynamic clamp restores bursting. Importantly, this burst-promoting effect requires a relatively fast BK activation/deactivation, as predicted by computational models. We also show that adding a fast activating BK conductance to spiking gonadotrophs converts the activity of these cells to bursting. Together, our results suggest that differences in BK channel expression may underlie the differences in electrical activity and basal hormone secretion levels among pituitary cell types and that the rapid rate of BK channel activation is key to its role in burst promotion. PMID:22090511

  13. Behavioral inspiratory inhibition: inactivated and activated respiratory cells.

    PubMed

    Orem, J

    1989-11-01

    1. Eleven adult cats were trained to stop inspiration in response to a conditioning stimulus. The conditioning stimuli were presented at the onset of inspiration at intervals of approximately 20-30 s. Intratracheal pressures, diaphragmatic activity, and the extracellular activity of single medullary respiratory neurons were recorded while the animals performed this response. 2. Inactivation of the diaphragm to the conditioning stimuli occurred at latencies that varied from 40 to 110 ms and averaged 74 +/- 32 (SD) ms. 3. The subjects of this report are 38 inspiratory neurons that were inactivated and 19 cells that were activated when inspiration was stopped behaviorally. These cells were located in the region of n. ambiguus and the ventrolateral n. of tractus solitarius. 4. The inspiratory cells that were inactivated behaviorally had the following characteristics: 1) Most had an augmenting inspiratory profile with (n = 14) or without (n = 9) postinspiratory activity. Other types were inspiratory throughout (n = 5), decrementing inspiratory (n = 3), tonic inspiratory (n = 4), early inspiratory (n = 2), and expiratory-inspiratory (n = 1). 2) Their mean discharge rate was 39 +/- 2.7 (SE) Hz. 3) The latency of their inactivation in response to the task averaged 81 +/- 4.9 (SE) ms, and 4) Their activity corresponded closely to breathing not only during the behavioral response but also during eupnea (eta 2 = 0.62 +/- 0.04, mean +/- SE) and respiratory acts such as sneezing, sniffing, meowing, and purring. 5. The cells that were activated when inspiration was stopped behaviorally had the following characteristics. 1) As a group, they had discharge profiles related to every phase of the respiratory cycle. 2) They were recorded in the same region as, and often simultaneously with, respiratory cells that were inactivated. 3) Their activity patterns were highly variable such that the signal strength and consistency of the respiratory component of that activity were weak (eta 2

  14. ETHYLENE RESPONSE FACTOR 74 (ERF74) plays an essential role in controlling a respiratory burst oxidase homolog D (RbohD)-dependent mechanism in response to different stresses in Arabidopsis.

    PubMed

    Yao, Yuan; He, Run Jun; Xie, Qiao Li; Zhao, Xian Hai; Deng, Xiao Mei; He, Jun Bo; Song, Lili; He, Jun; Marchant, Alan; Chen, Xiao-Yang; Wu, Ai-Min

    2017-03-01

    Recent studies indicate that the ETHYLENE RESPONSE FACTOR VII (ERF-VII) transcription factor is an important regulator of osmotic and hypoxic stress responses in plants. However, the molecular mechanism of ERF-VII-mediated transcriptional regulation remains unclear. Here, we investigated the role of ERF74 (a member of the ERF-VII protein family) by examining the abiotic stress tolerance of an ERF74 overexpression line and a T-DNA insertion mutant using flow cytometry, transactivation and electrophoretic mobility shift assays. 35S::ERF74 showed enhanced tolerance to drought, high light, heat and aluminum stresses, whereas the T-DNA insertion mutant erf74 and the erf74;erf75 double mutant displayed higher sensitivity. Using flow cytometry analysis, we found that erf74 and erf74;erf75 lines lack the reactive oxygen species (ROS) burst in the early stages of various stresses, as a result of the lower expression level of RESPIRATORY BURST OXIDASE HOMOLOG D (RbohD). Furthermore, ERF74 directly binds to the promoter of RbohD and activates its expression under different abiotic stresses. Moreover, induction of stress marker genes and ROS-scavenging enzyme genes under various stress conditions is dependent on the ERF74-RbohD-ROS signal pathway. We propose a pathway that involves ERF74 acting as an on-off switch controlling an RbohD-dependent mechanism in response to different stresses, subsequently maintaining hydrogen peroxide (H2 O2 ) homeostasis in Arabidopsis.

  15. Detection of Spectral Evolution in the Bursts Emitted During the 2008-2009 Active Episode of SGR J1550 - 5418

    NASA Technical Reports Server (NTRS)

    von Kienlin, Andreas; Gruber, David; Kouveliotou, Chryssa; Granot, Jonathan; Baring, Matthew G.; Gogus, Ersin; Huppenkothen, Daniela; Kaneko, Yuki; Lin, Lin; Watts, Anna L.; Bhat, Narayana; Guiriec, Sylvain; van der Horst, Alexander J.; Bissaldi, Elisabetta; Greiner, Jochen; Meegan, Charles A.; Paciesas, William S.; Preece, Robert D.; Rau, Arne

    2012-01-01

    In early October 2008, the Soft Gamma Repeater SGRJ1550 - 5418 (1E1547.0 - 5408, AXJ155052 - 5418, PSR J1550 - 5418) became active, emitting a series of bursts which triggered the Fermi Gamma-ray Burst Monitor (GBM) after which a second especially intense activity period commenced in 2009 January and a third, less active period was detected in 2009 March-April. Here we analyze the GBM data of all the bursts from the first and last active episodes. We performed temporal and spectral analysis for all events and found that their temporal characteristics are very similar to the ones of other SGR bursts, as well the ones reported for the bursts of the main episode (average burst durations 170ms). In addition, we used our sample of bursts to quantify the systematic uncertainties of the GBM location algorithm for soft gamma-ray transients to less than or equal to 8 degrees. Our spectral analysis indicates significant spectral evolution between the first and last set of events. Although the 2008 October events are best fit with a single blackbody function, for the 2009 bursts an Optically Thin Thermal Bremsstrahlung (OTTB) is clearly preferred. We attribute this evolution to changes in the magnetic field topology of the source, possibly due to effects following the very energetic main bursting episode.

  16. Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

    NASA Technical Reports Server (NTRS)

    Noohi, F.; Kinnaird, C.; Wood, S.; Bloomberg, J.; Mulavara, A.; Seidler, R.

    2016-01-01

    The current study characterizes brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either the vestibulo-spinal reflex (saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)), or the ocular muscle response (utricle-mediated ocular VEMP (oVEMP)). Some researchers have reported that air-conducted skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for the subjects. However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying otolith-specific deficits, including gait and balance problems that astronauts experience upon returning to earth. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation. Here we hypothesized that skull taps elicit similar patterns of cortical activity as the auditory tone bursts, and previous vestibular imaging studies. Subjects wore bilateral MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in the supine position, with eyes closed. Subjects received both forms of the stimulation in a counterbalanced fashion. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular system, resulting in the vestibular cortical response. Auditory tone bursts were also delivered for comparison. To validate our stimulation method, we measured the ocular VEMP outside of the scanner. This measurement showed that both skull tap and auditory

  17. Airflow synchronous with oscillatory acceleration reflects involuntary respiratory muscle activity.

    PubMed

    Brown, Richard E; Lee, Hsueh-Tze; Loring, Stephen H

    2004-06-25

    To explore mechanisms causing involuntary airflow synchronous with oscillatory axial whole body acceleration (oscillatory axial acceleration, OAA) such as that during locomotion, we monitored airflow, acceleration, and electromyograms (EMGs) of the rib cage and abdominal muscles in standing subjects undergoing OAA at 3, 6, and 9 Hz at accelerations of 0.1-0.95 g. Subjects relaxed or performed static respiratory maneuvers at constant lung volume with glottis open. Oscillatory airflows (0.01-3.01 s(-1)) synchronous with OAA were not consistent with expectations for a passive respiratory system, and were larger during active respiratory efforts than during relaxation. Peak inspiratory airflow usually preceded peak upward acceleration by 90-180 degrees. In 80% of runs with respiratory muscles voluntarily activated or relaxed, EMGs showed activity synchronous with OAA. Changes in periodic muscle activity coincided with changes in oscillatory airflow. We conclude that periodic muscle activity, probably a reflex response to body wall deformation during OAA, strongly influences the involuntary airflow synchronous with OAA.

  18. Pontine respiratory activity involved in inspiratory/expiratory phase transition

    PubMed Central

    Mörschel, Michael; Dutschmann, Mathias

    2009-01-01

    Control of the timing of the inspiratory/expiratory (IE) phase transition is a hallmark of respiratory pattern formation. In principle, sensory feedback from pulmonary stretch receptors (Breuer–Hering reflex, BHR) is seen as the major controller for the IE phase transition, while pontine-based control of IE phase transition by both the pontine Kölliker–Fuse nucleus (KF) and parabrachial complex is seen as a secondary or backup mechanism. However, previous studies have shown that the BHR can habituate in vivo. Thus, habituation reduces sensory feedback, so the role of the pons, and specifically the KF, for IE phase transition may increase dramatically. Pontine-mediated control of the IE phase transition is not completely understood. In the present review, we discuss existing models for ponto-medullary interaction that may be involved in the control of inspiratory duration and IE transition. We also present intracellular recordings of pontine respiratory units derived from an in situ intra-arterially perfused brainstem preparation of rats. With the absence of lung inflation, this preparation generates a normal respiratory pattern and many of the recorded pontine units demonstrated phasic respiratory-related activity. The analysis of changes in membrane potentials of pontine respiratory neurons has allowed us to propose a number of pontine-medullary interactions not considered before. The involvement of these putative interactions in pontine-mediated control of IE phase transitions is discussed. PMID:19651653

  19. Burst and Persistent Emission Properties during the Recent Active Episode of the Anomalous X-Ray Pulsar 1E 1841-045

    NASA Technical Reports Server (NTRS)

    Lin, Lin; Kouveliotou, Chryssa; Gogus, Ersin; van der Horst, Alexander J.; Watts, Anna L.; Baring, Matthew G.; Kaneko, Yuki; Wijers, Ralph A. M. J.; Woods, Peter M.; Barthelmy, Scott; Burgess, J. Michael; Chaplin, Vandiver; Gehrels, Neil; Goldstein, Adam; Granot, Jonathan; Guiriec, Sylvain; Mcenery, Julie; Preece, Robert D.; Tierney, David; van der Klis, Michiel; von Kienlin, Andreas; Zhang, Shuang Nan

    2011-01-01

    SWift/BAT detected the first burst from 1E 1841-045 in May 2010 with intermittent burst activity recorded through at least July 2011. Here we present Swift and Fermi/GBM observations of this burst activity and search for correlated changes to the persistent X-ray emission of the source. The T90 durations of the bursts range between 18 - 140 ms, comparable to other magnetar burst durations, while the energy released in each burst ranges between (0.8-25) x 1038 erg, which is in the low side of SGR bursts. We find that the bursting activity did not have a significant effect on the persistent flux level of the source. We argue that the mechanism leading to this sporadic burst activity in IE 1841-045 might not involve large scale restructuring (either crustal or magnetospheric) as seen in other magnetar sources.

  20. The activity of grepafloxacin against respiratory pathogens in the UK.

    PubMed

    Wise, R; Andrews, J M

    1997-12-01

    The in-vitro activity of grepafloxacin was compared with that of other antimicrobials against respiratory tract pathogens collected from 15 UK laboratories over the winter of 1995-96. Penicillin-resistant Streptococcus pneumoniae was not encountered, but macrolide resistance was seen in approximately 10% of strains. Grepafloxacin (MIC90 0.25 mg/L) was four- to eight-fold more active than ciprofloxacin. Twelve percent of Haemophilus influenzae were beta-lactamase producers, macrolides were relatively inactive yet fluoroquinolones were highly active. Moraxella catarrhalis were highly susceptible to fluoroquinolones and macrolides. The activity of grepafloxacin against respiratory tract pathogens should make it a useful agent in the treatment of infections at this site.

  1. Respiratory-like rhythmic activity can be produced by an excitatory network of non-pacemaker neuron models.

    PubMed

    Kosmidis, Efstratios K; Pierrefiche, Olivier; Vibert, Jean-François

    2004-08-01

    It is still unclear whether the respiratory-like rhythm observed in slice preparations containing the pre-Bötzinger complex is of pacemaker or network origin. The rhythm persists in the absence of inhibition, but blocking pacemaker activity did not always result in rhythm abolition. We developed a computational model of the slice to show that respiratory-like rhythm can emerge as a network property without pacemakers or synaptic inhibition. The key currents of our model cell are the low- and high-threshold calcium currents and the calcium-dependent potassium current. Depolarization of a single unit by current steps or by raising the external potassium concentration can induce periodic bursting activity. Gaussian stimulation increased the excitability of the model without evoking oscillatory activity, as indicated by autocorrelation analysis. In response to hyperpolarizing pulses, the model produces prolonged relative refractory periods. At the network level, an increase of external potassium concentration triggers rhythmic activity that can be attributed to cellular periodic bursting, network properties, or both, depending on different parameters. Gaussian stimulation also induces rhythmic activity that depends solely on network properties. In all cases, the calcium-dependent potassium current has a central role in burst termination and interburst duration. However, when periodic inhibition is considered, the activation of this current is responsible for the characteristic amplification ramp of the emerged rhythm. Our results may explain controversial results from studies blocking pacemakers in vitro and show a shift in the role of the calcium-dependent potassium current in the presence of network inhibition.

  2. Glucocorticoids Inhibit CRH/AVP-Evoked Bursting Activity of Male Murine Anterior Pituitary Corticotrophs

    PubMed Central

    Duncan, Peter J.; Tabak, Joël; Ruth, Peter; Bertram, Richard

    2016-01-01

    Corticotroph cells from the anterior pituitary are an integral component of the hypothalamic-pituitary-adrenal (HPA) axis, which governs the neuroendocrine response to stress. Corticotrophs are electrically excitable and fire spontaneous single-spike action potentials and also display secretagogue-induced bursting behavior. The HPA axis function is dependent on effective negative feedback in which elevated plasma glucocorticoids result in inhibition at the level of both the pituitary and the hypothalamus. In this study, we have used an electrophysiological approach coupled with mathematical modeling to investigate the regulation of spontaneous and CRH/arginine vasopressin-induced activity of corticotrophs by glucocorticoids. We reveal that pretreatment of corticotrophs with 100 nM corticosterone (CORT; 90 and 150 min) reduces spontaneous activity and prevents a transition from spiking to bursting after CRH/arginine vasopressin stimulation. In addition, previous studies have identified a role for large-conductance calcium- and voltage-activated potassium (BK) channels in the generation of secretagogue-induced bursting in corticotrophs. Using the dynamic clamp technique, we demonstrated that CRH-induced bursting can be switched to spiking by subtracting a fast BK current, whereas the addition of a fast BK current can induce bursting in CORT-treated cells. In addition, recordings from BK knockout mice (BK−/−) revealed that CORT can also inhibit excitability through BK-independent mechanisms to control spike frequency. Thus, we have established that glucocorticoids can modulate multiple properties of corticotroph electrical excitability through both BK-dependent and BK-independent mechanisms. PMID:27254001

  3. EMG burst presence probability: a joint time-frequency representation of muscle activity and its application to onset detection.

    PubMed

    Liu, Jie; Ying, Dongwen; Rymer, William Zev

    2015-04-13

    The purpose of this study was to quantify muscle activity in the time-frequency domain, therefore providing an alternative tool to measure muscle activity. This paper presents a novel method to measure muscle activity by utilizing EMG burst presence probability (EBPP) in the time-frequency domain. The EMG signal is grouped into several Mel-scale subbands, and the logarithmic power sequence is extracted from each subband. Each log-power sequence can be regarded as a dynamic process that transits between the states of EMG burst and non-burst. The hidden Markov model (HMM) was employed to elaborate this dynamic process since HMM is intrinsically advantageous in modeling the temporal correlation of EMG burst/non-burst presence. The EBPP was eventually yielded by HMM based on the criterion of maximum likelihood. Our approach achieved comparable performance with the Bonato method.

  4. Influences of neck afferents on sympathetic and respiratory nerve activity.

    PubMed

    Bolton, P S; Kerman, I A; Woodring, S F; Yates, B J

    1998-11-15

    It is well established that the vestibular system influences the sympathetic nervous system and the respiratory system; presumably, vestibulosympathetic and vestibulorespiratory responses participate in maintaining stable blood pressure and blood oxygenation during movement and changes in posture. Many brainstem neurons that generate vestibulospinal reflexes integrate signals from the labyrinth and neck muscles to distinguish between head movements on a stable body and whole body movements. In the present study, responses were recorded from the splanchnic (sympathetic), hypoglossal (inspiratory) and abdominal (expiratory) nerves during stimulation of the C2 dorsal root ganglion or C2 or C3 nerve branches innervating dorsal neck muscles. Stimulation of neck afferents using low current intensities, in many cases less than twice the threshold for producing an afferent volley recordable from the cord dorsum, elicited changes in sympathetic and respiratory nerve activity. These data suggest that head rotation on a stable body would elicit both cervical and vestibular inputs to respiratory motoneurons and sympathetic preganglionic neurons. The effects of cervical afferent stimulation on abdominal, splanchnic and hypoglossal nerve activity were not abolished by transection of the brainstem caudal to the vestibular nuclei; thus, pathways in addition to those involving the vestibular nuclei are involved in relaying cervical inputs to sympathetic preganglionic neurons and respiratory motoneurons. Transection of the C1-3 dorsal roots enhanced responses of the splanchnic and abdominal nerves to pitch head rotations on a fixed body but diminished responses of the hypoglossal nerve. Thus, neck and vestibular afferent influences on activity of respiratory pump muscles and sympathetic outflow appear to be antagonistic, so that responses will occur during whole body movements but not head movements on a stationary trunk. In contrast, neck and vestibular influences on tongue

  5. Cannabinoid Receptor Activation Reverses Kainate-Induced Synchronized Population Burst Firing in Rat Hippocampus

    PubMed Central

    Mason, Rob; Cheer, Joseph F.

    2009-01-01

    Cannabinoids have been shown to possess anticonvulsant properties in whole animal models of epilepsy. The present investigation sought to examine the effects of cannabinoid receptor activation on kainic acid (KA)-induced epileptiform neuronal excitability. Under urethane anesthesia, acute KA treatment (10 mg kg−1, i.p.) entrained the spiking mode of simultaneously recorded neurons from random firing to synchronous bursting (% change in burst rate). Injection of the high-affinity cannabinoid agonist (-)-11-hydroxy-8-tetrahydrocannabinol-dimethyl-heptyl (HU210, 100 μg kg−1, i.p.) following KA markedly reduced the burst frequency (% decrease in burst frequency) and reversed synchronized firing patterns back to baseline levels. Pre-treatment with the central cannabinoid receptor (CB1) antagonist N-piperidino-5-(4-clorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (rimonabant, SR141716A 3 mg kg−1, i.p.) completely prevented the actions of HU210. The present results indicate that cannabinoids exert their antiepileptic effects by impeding pathological synchronization of neuronal networks in the hippocampus. PMID:19562087

  6. New lanostanes and naphthoquinones isolated from Antrodia salmonea and their antioxidative burst activity in human leukocytes.

    PubMed

    Shen, Chien-Chang; Shen, Yuh-Chiang; Wang, Yea-Hwey; Lin, Lie-Chwen; Don, Ming-Jaw; Liou, Kuo-Tong; Wang, Wen-Yen; Hou, Yu-Chang; Chang, Tun-Tschu

    2006-02-01

    Four new compounds were isolated from the basidiomata of the fungus Antrodia salmonea, a newly identified species of Antrodia (Aphyllophorales) in Taiwan. These new compounds are named as lanosta-8,24-diene-3beta,15alpha,21-triol (1), 24-methylenelanost-8-ene-3beta,15alpha,21-triol (2), 2,3-dimethoxy-5-(2',5'-dimethoxy-3',4'-methylenedioxyphenyl)-7-methyl-[1,4]-naphthoquinone (3), and 2,3-dimethoxy-6-(2',5'-dimethoxy-3',4'-methylenedioxyphenyl)-7-methyl-[1,4]-naphthoquinone (4), respectively. Their structures were elucidated by spectroscopic methods. An in vitro cellular functional assay was performed to evaluate their anti-oxidative burst activity in human leukocytes. They showed inhibitory effects against phorbol 12-myristate-13-acetate (PMA), a direct protein kinase C activator, induced oxidative burst in neutrophils (PMN) and mononuclear cells (MNC) with 50 % inhibitory concentration (IC(50)) ranging from 3.5 to 25.8 microM. The potency order of these compounds in PMA-activated leukocytes was as 1 > 3 > 4 > 2. They were relatively less effective in formyl-Met-Leu-Phe (fMLP), a G-protein coupled receptor agonist, induced oxidative burst, except for compounds 3 and 4 in fMLP-activated PMN. These results indicated that three (1, 3, and 4) of these four newly identified compounds displayed anti-oxidative effect in human leukocytes with different potency and might confer anti-inflammatory activity to these drugs.

  7. Effect of structured physical activity on respiratory outcomes in sedentary elderly adults with mobility limitations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OBJECTIVES: To evaluate the effect of structured physical activity on respiratory outcomes in community dwelling elderly adults with mobility limitations. DESIGN: Multicenter, randomized trial of physical activity vs health education, with respiratory variables prespecified as tertiary outcomes over...

  8. Bursting Activity of Substantia Nigra pars Reticulata Neurons in Mouse Parkinsonism in Awake and Anesthetized States

    PubMed Central

    Lobb, CJ; Jaeger, D

    2015-01-01

    Electrophysiological changes in basal ganglia neurons are hypothesized to underlie motor dysfunction in Parkinson’s disease (PD). Previous results in head-restrained MPTP-treated non-human primates have suggested that increased bursting within the basal ganglia and related thalamic and cortical areas may be a hallmark of pathophysiological activity. In this study, we investigated whether there is increased bursting in substantia nigra pars reticulata (SNpr) output neurons in anesthetized and awake, head-restrained unilaterally lesioned 6-OHDA mice when compared to control mice. Confirming previous studies, we show that there are significant changes in the firing rate and pattern in SNpr neuron activity under urethane anesthesia. The regular firing pattern of control urethane-anesthetized SNpr neurons was not present in the 6-OHDA-lesioned group, as the latter neurons instead became phase locked with cortical slow wave activity (SWA). Next, we examined whether such robust electrophysiological changes between groups carried over to the awake state. SNpr neurons from both groups fired at much higher frequencies in the awake state than in the anesthetized state and surprisingly showed only modest changes between awake control and 6-OHDA groups. While there were no differences in firing rate between groups in the awake state, an increase in the coefficient of variation (CV) was observed in the 6-OHDA group. Contrary to the bursting hypothesis, this increased CV was not due to changes in bursting but was instead due to a mild increase in pausing. Together, these results suggest that differences in SNpr activity between control and 6-OHDA lesioned mice may be strongly influenced by changes in network activity during different arousal and behavioral states. PMID:25576395

  9. Transition in subicular burst firing neurons from epileptiform activity to suppressed state by feedforward inhibition.

    PubMed

    Sah, Nirnath; Sikdar, Sujit K

    2013-08-01

    The subiculum, a para-hippocampal structure positioned between the cornu ammonis 1 subfield and the entorhinal cortex, has been implicated in temporal lobe epilepsy in human patients and in animal models of epilepsy. The structure is characterized by the presence of a significant population of burst firing neurons that has been shown previously to lead epileptiform activity locally. Phase transitions in epileptiform activity in neurons following a prolonged challenge with an epileptogenic stimulus has been shown in other brain structures, but not in the subiculum. Considering the importance of the subicular burst firing neurons in the propagation of epileptiform activity to the entorhinal cortex, we have explored the phenomenon of phase transitions in the burst firing neurons of the subiculum in an in vitro rat brain slice model of epileptogenesis. Whole-cell patch-clamp and extracellular field recordings revealed a distinct phenomenon in the subiculum wherein an early hyperexcitable state was followed by a late suppressed state upon continuous perfusion with epileptogenic 4-aminopyridine and magnesium-free medium. The suppressed state was characterized by inhibitory post-synaptic potentials in pyramidal excitatory neurons and bursting activity in local fast-spiking interneurons at a frequency of 0.1-0.8 Hz. The inhibitory post-synaptic potentials were mediated by GABAA receptors that coincided with excitatory synaptic inputs to attenuate action potential discharge. These inhibitory post-synaptic potentials ceased following a cut between the cornu ammonis 1 and subiculum. The suppression of epileptiform activity in the subiculum thus represents a homeostatic response towards the induced hyperexcitability. Our results suggest the importance of feedforward inhibition in exerting this homeostatic control.

  10. The 2001 April Burst Activation of SGR 1900-14: Pulse Properties and Torque

    NASA Technical Reports Server (NTRS)

    Woods, P. M.; Kouveliotou, C.; Goegues, E.; Finger, M. H.; Feroci, M.; Mereghetti, S.; Swank, J. H.; Hurley, K.; Heise, J.; Smith D.

    2003-01-01

    We report on observations of SGR 1900+14 made with the Rossi X-Ray Timing Explorer (RXTE) and BeppoSAXduring the 2001 April burst activation of the source. Using these data, we measure the spin-down torque on the star and confirm earlier findings that the torque and burst activity are not directly correlated. We compare the X-ray pulse profile to the gamma-ray profile during the April 18 intermediate flare and show that (1) their shapes are similar and (1) the gamma-ray profile aligns closely in phase with the X-ray pulsations. The good phase alignment of the gamma-ray and X-ray profiles suggests that there was no rapid spin-down following this flare of the magnitude inferred for the August 27 giant flare. We discuss how these observations further constrain magnetic field reconfiguration models for the large flares of SGRs.

  11. Cardiac-locked bursts of muscle sympathetic nerve activity are absent in familial dysautonomia

    PubMed Central

    Macefield, Vaughan G; Norcliffe-Kaufmann, Lucy; Axelrod, Felicia B; Kaufmann, Horacio

    2013-01-01

    Familial dysautonomia (Riley–Day syndrome) is an hereditary sensory and autonomic neuropathy (HSAN type III), expressed at birth, that is associated with reduced pain and temperature sensibilities and absent baroreflexes, causing orthostatic hypotension as well as labile blood pressure that increases markedly during emotional excitement. Given the apparent absence of functional baroreceptor afferents, we tested the hypothesis that the normal cardiac-locked bursts of muscle sympathetic nerve activity (MSNA) are absent in patients with familial dysautonomia. Tungsten microelectrodes were inserted percutaneously into muscle or cutaneous fascicles of the common peroneal nerve in 12 patients with familial dysautonomia. Spontaneous bursts of MSNA were absent in all patients, but in five patients we found evidence of tonically firing sympathetic neurones, with no cardiac rhythmicity, that increased their spontaneous discharge during emotional arousal but not during a manoeuvre that unloads the baroreceptors. Conversely, skin sympathetic nerve activity (SSNA), recorded in four patients, appeared normal. We conclude that the loss of phasic bursts of MSNA and the loss of baroreflex modulation of muscle vasoconstrictor drive contributes to the poor control of blood pressure in familial dysautonomia, and that the increase in tonic firing of muscle vasoconstrictor neurones contributes to the increase in blood pressure during emotional excitement. PMID:23165765

  12. [Electrical activities of bursting-firing neurons in epileptic network reestablishment of rat hippocampus].

    PubMed

    Wang, Wen-Ting; Qin, Xing-Kui; Yin, Shi-Jin; Han, Dan

    2003-12-25

    ipsilateral or contralateral anterior dorsal HPC were elicited by the ATPDH. The results obtained suggest that bursting-firing of single BFNs is produced by the ATPDH in the anterior dorsal HPC along the longitudinal axis of the ipsilateral HPC or across the hemisphere to the opposite HPC. Rhythmic activities of the BFN may be implicated in the epileptic network reestablishment of the HPC. On the other hand, synaptic modulation of the BFN temporal series might be responsible for pathophysiological information transmission in the HPC-epileptic network.

  13. Cloning and expression analysis of the Ccrboh gene encoding respiratory burst oxidase in Citrullus colocynthis and grafting onto Citrullus lanatus (watermelon).

    PubMed

    Si, Ying; Dane, Fenny; Rashotte, Aaron; Kang, Kwonkyoo; Singh, Narendra K

    2010-06-01

    A full-length drought-responsive gene Ccrboh, encoding the respiratory burst oxidase homologue (rboh), was cloned in Citrullus colocynthis, a very drought-tolerant cucurbit species. The robh protein, also named NADPH oxidase, is conserved in plants and animals, and functions in the production of reactive oxygen species (ROS). The Ccrboh gene accumulated in a tissue-specific pattern when C. colocynthis was treated with PEG, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), or NaCl, while the homologous rboh gene did not show any change in C. lanatus var. lanatus, cultivated watermelon, during drought. Grafting experiments were conducted using C. colocynthis or C. lanatus as the rootstock or scion. Results showed that the rootstock significantly affects gene expression in the scion, and some signals might be transported from the root to the shoot. Ccrboh in C. colocynthis was found to function early during plant development, reaching high mRNA transcript levels 3 d after germination. The subcellular location of Ccrboh was investigated by transient expression of the 35S::Ccrboh::GFP fusion construct in protoplasts. The result confirmed that Ccrboh is a transmembrane protein. Our data suggest that Ccrboh might be functionally important during the acclimation of plants to stress and also in plant development. It holds great promise for improving drought tolerance of other cucurbit species.

  14. Interactions between cardiac, respiratory, and brain activity in humans

    NASA Astrophysics Data System (ADS)

    Musizza, Bojan; Stefanovska, Aneta

    2005-05-01

    The electrical activity of the heart (ECG), respiratory function and electric activity of the brain (EEG) were simultaneously recorded in conscious, healthy humans. Instantaneous frequencies of the heart beat, respiration and α-waves were then determined from 30-minutes recordings. The instantaneous cardiac frequency was defined as the inverse value of the time interval between two consecutive R-peaks. The instantaneous respiratory frequency was obtained from recordings of the excursions of thorax by application of the Hilbert transform. To obtain the instantaneous frequency of α-waves, the EEG signal recorded from the forehead was first analysed using the wavelet transform. Then the frequency band corresponding to α-waves was extracted and the Hilbert transform applied. Synchronization analysis was performed and the direction of coupling was ascertained, using pairs of instantaneous frequencies in each case. It is shown that the systems are weakly bidirectionally coupled. It was confirmed that, in conscious healthy humans, respiration drives cardiac activity. We also demonstrate from these analyses that α-activity drives both respiration and cardiac activity.

  15. Rapid toxicity testing based on mitochondrial respiratory activity

    SciTech Connect

    Haubenstricker, M.E. ); Holodnick, S.E.; Mancy, K.H. ); Brabec, M.J. )

    1990-05-01

    The need exists for rapid and inexpensive methods to determine the health effects of environmental contaminants on biological systems. One of the current research approaches for assessing cytotoxicity is to monitor the respiratory activity of the mitochondrion, a sensitive, nonspecific subcellular target site. Detected changes in mitochondrial function after the addition of a test chemical could be correlated to toxic effects. Mitochondrial respiration can be characterized by three indices: state 3 and state 4 respiratory rates, and the respiratory control ratio (RCR). State 4, the idle or resting state, results when coupled mitochondrial respire in a medium containing inorganic phosphate and a Kreb's cycle substrate in the absence of a phosphate acceptor such as adenosine diphosphate (ADP). In the presence of ADP the respiration rate increases to a maximum (state 3), accompanied by phosphorylation of ADP to adenosine triphosphate (ATP). The ratio of state 3 to state 4, or RCR, indicates how tightly the oxidative phosphorylation process is coupled. The synthesis of ATP by mitochondria is influenced by a number of compounds, most of which are either uncouplers or inhibitors.

  16. Multiplex Eukaryotic Transcription (In)activation: Timing, Bursting and Cycling of a Ratchet Clock Mechanism.

    PubMed

    Rybakova, Katja N; Bruggeman, Frank J; Tomaszewska, Aleksandra; Moné, Martijn J; Carlberg, Carsten; Westerhoff, Hans V

    2015-04-01

    Activation of eukaryotic transcription is an intricate process that relies on a multitude of regulatory proteins forming complexes on chromatin. Chromatin modifications appear to play a guiding role in protein-complex assembly on chromatin. Together, these processes give rise to stochastic, often bursting, transcriptional activity. Here we present a model of eukaryotic transcription that aims to integrate those mechanisms. We use stochastic and ordinary-differential-equation modeling frameworks to examine various possible mechanisms of gene regulation by multiple transcription factors. We find that the assembly of large transcription factor complexes on chromatin via equilibrium-binding mechanisms is highly inefficient and insensitive to concentration changes of single regulatory proteins. An alternative model that lacks these limitations is a cyclic ratchet mechanism. In this mechanism, small protein complexes assemble sequentially on the promoter. Chromatin modifications mark the completion of a protein complex assembly, and sensitize the local chromatin for the assembly of the next protein complex. In this manner, a strict order of protein complex assemblies is attained. Even though the individual assembly steps are highly stochastic in duration, a sequence of them gives rise to a remarkable precision of the transcription cycle duration. This mechanism explains how transcription activation cycles, lasting for tens of minutes, derive from regulatory proteins residing on chromatin for only tens of seconds. Transcriptional bursts are an inherent feature of such transcription activation cycles. Bursting transcription can cause individual cells to remain in synchrony transiently, offering an explanation of transcriptional cycling as observed in cell populations, both on promoter chromatin status and mRNA levels.

  17. Respiratory muscle strength in the physically active elderly.

    PubMed

    Summerhill, Eleanor M; Angov, Nadia; Garber, Carol; McCool, F Dennis

    2007-12-01

    Advancing age is associated with a decline in the strength of the skeletal muscles, including those of respiration. Respiratory muscles can be strengthened with nonrespiratory activities. We therefore hypothesized that regular exercise in the elderly would attenuate this age-related decline in respiratory muscle strength. Twenty-four healthy subjects older than 65 years were recruited (11 males and 13 females). A comprehensive physical activity survey was administered, and subjects were categorized as active (n = 12) or inactive (n = 12). Each subject underwent testing of maximum inspiratory and expiratory pressures (PI(max) and PE(max)). Diaphragmatic thickness (tdi) was measured via two-dimensional B-mode ultrasound. There were no significant differences between the active and inactive groups with respect to age (75 vs. 73 years) or body weight (69.1vs. 69.9 kg). There were more women (9) than men (3) in the inactive group. Diaphragm thickness was greater in the active group (0.31 +/- 0.06 cm vs. 0.25 +/- 0.04 cm; p = 0.011). PE(max) and PI(max) were also greater in the active group (130 +/- 44 cm H(2)O vs. 80 +/- 24 cm H(2)O; p = 0.002; and 99 +/- 32 cm H(2)O vs. 75 +/- 14 cm H(2)O; p = 0.03). There was a positive association between PI(max )and tdi (r = 0.43, p = 0.03). Regular exercise was positively associated with diaphragm muscle thickness in this cohort. As PE(max) was higher in the active group, we postulate that recruitment of the diaphragm and abdominal muscles during nonrespiratory activities may be the source of this training effect.

  18. Antioxidant activity of Calendula officinalis extract: inhibitory effects on chemiluminescence of human neutrophil bursts and electron paramagnetic resonance spectroscopy.

    PubMed

    Braga, Pier Carlo; Dal Sasso, Monica; Culici, Maria; Spallino, Alessandra; Falchi, Mario; Bertelli, Aldo; Morelli, Roberto; Lo Scalzo, Roberto

    2009-01-01

    There is growing interest in natural chemical compounds from aromatic, spicy, medicinal and other plants with antioxidant properties in order to find new sources of compounds inactivating free radicals generated by metabolic pathways within body tissue and cells, mainly polymorphonuclear leukocytes (PMNs) whose overregulated recruitment and activation generate a large amount of reactive oxygen species (ROS) and reactive nitrogen species (RNS), leading to an imbalance of redox homeostasis and oxidative stress. The aim of this study was to examine whether a propylene glycol extract of Calendula officinalis interferes with ROS and RNS during the PMN respiratory bursts, and to establish the lowest concentration at which it still exerts antioxidant activity by means of luminol-amplified chemiluminescence. Electron paramagnetic resonance (EPR) spectroscopy was also used in order to confirm the activity of the C. officinalis extract. The C. officinalis extract exerted its anti-ROS and anti-RNS activity in a concentration-dependent manner, with significant effects being observed at even very low concentrations: 0.20 microg/ml without L-arginine, 0.10 microg/ml when L-arginine was added to the test with phorbol 12-myristate 13-acetate and 0.05 microg/ml when it was added to the test with N-formyl-methionyl-leucyl-phenylalanine. The EPR study confirmed these findings, 0.20 microg/ml being the lowest concentration of C. officinalis extract that significantly reduced 2,2-diphenyl-1-picrylhydrazyl. These findings are interesting for improving the antioxidant network and restoring the redox balance in human cells with plant-derived molecules as well as extending the possibility of antagonizing the oxidative stress generated in living organisms when the balance is in favor of free radicals as a result of the depletion of cell antioxidants.

  19. Activated mouse eosinophils protect against lethal respiratory virus infection.

    PubMed

    Percopo, Caroline M; Dyer, Kimberly D; Ochkur, Sergei I; Luo, Janice L; Fischer, Elizabeth R; Lee, James J; Lee, Nancy A; Domachowske, Joseph B; Rosenberg, Helene F

    2014-01-30

    Eosinophils are recruited to the airways as a prominent feature of the asthmatic inflammatory response where they are broadly perceived as promoting pathophysiology. Respiratory virus infections exacerbate established asthma; however, the role of eosinophils and the nature of their interactions with respiratory viruses remain uncertain. To explore these questions, we established acute infection with the rodent pneumovirus, pneumonia virus of mice (PVM), in 3 distinct mouse models of Th2 cytokine-driven asthmatic inflammation. We found that eosinophils recruited to the airways of otherwise naïve mice in response to Aspergillus fumigatus, but not ovalbumin sensitization and challenge, are activated by and degranulate specifically in response to PVM infection. Furthermore, we demonstrate that activated eosinophils from both Aspergillus antigen and cytokine-driven asthma models are profoundly antiviral and promote survival in response to an otherwise lethal PVM infection. Thus, although activated eosinophils within a Th2-polarized inflammatory response may have pathophysiologic features, they are also efficient and effective mediators of antiviral host defense.

  20. Short-term sustained hypoxia induces changes in the coupling of sympathetic and respiratory activities in rats

    PubMed Central

    Moraes, Davi J A; Bonagamba, Leni G H; Costa, Kauê M; Costa-Silva, João H; Zoccal, Daniel B; Machado, Benedito H

    2014-01-01

    Individuals experiencing sustained hypoxia (SH) exhibit adjustments in the respiratory and autonomic functions by neural mechanisms not yet elucidated. In the present study we evaluated the central mechanisms underpinning the SH-induced changes in the respiratory pattern and their impact on the sympathetic outflow. Using a decerebrated arterially perfused in situ preparation, we verified that juvenile rats exposed to SH (10% O2) for 24 h presented an active expiratory pattern, with increased abdominal, hypoglossal and vagal activities during late-expiration (late-E). SH also enhanced the activity of augmenting-expiratory neurones and depressed the activity of post-inspiratory neurones of the Bötzinger complex (BötC) by mechanisms not related to changes in their intrinsic electrophysiological properties. SH rats exhibited high thoracic sympathetic activity and arterial pressure levels associated with an augmented firing frequency of pre-sympathetic neurones of the rostral ventrolateral medulla (RVLM) during the late-E phase. The antagonism of ionotropic glutamatergic receptors in the BötC/RVLM abolished the late-E bursts in expiratory and sympathetic outputs of SH rats, indicating that glutamatergic inputs to the BötC/RVLM are essential for the changes in the expiratory and sympathetic coupling observed in SH rats. We also observed that the usually silent late-E neurones of the retrotrapezoid nucleus/parafacial respiratory group became active in SH rats, suggesting that this neuronal population may provide the excitatory drive essential to the emergence of active expiration and sympathetic overactivity. We conclude that short-term SH induces the activation of medullary expiratory neurones, which affects the pattern of expiratory motor activity and its coupling with sympathetic activity. PMID:24614747

  1. Reconstruction of burst activity from calcium imaging of neuronal population via Lq minimization and interval screening

    PubMed Central

    Quan, Tingwei; Lv, Xiaohua; Liu, Xiuli; Zeng, Shaoqun

    2016-01-01

    Calcium imaging is becoming an increasingly popular technology to indirectly measure activity patterns in local neuronal networks. Based on the dependence of calcium fluorescence on neuronal spiking, two-photon calcium imaging affords single-cell resolution of neuronal population activity. However, it is still difficult to reconstruct neuronal activity from complex calcium fluorescence traces, particularly for traces contaminated by noise. Here, we describe a robust and efficient neuronal-activity reconstruction method that utilizes Lq minimization and interval screening (IS), which we refer to as LqIS. The simulation results show that LqIS performs satisfactorily in terms of both accuracy and speed of reconstruction. Reconstruction of simulation and experimental data also shows that LqIS has advantages in terms of the recall rate, precision rate, and timing error. Finally, LqIS is demonstrated to effectively reconstruct neuronal burst activity from calcium fluorescence traces recorded from large-size neuronal population. PMID:27375930

  2. Stimulus information stored in lasting active and hidden network states is destroyed by network bursts.

    PubMed

    Dranias, Mark R; Westover, M Brandon; Cash, Sidney; VanDongen, Antonius M J

    2015-01-01

    In both humans and animals brief synchronizing bursts of epileptiform activity known as interictal epileptiform discharges (IEDs) can, even in the absence of overt seizures, cause transient cognitive impairments (TCI) that include problems with perception or short-term memory. While no evidence from single units is available, it has been assumed that IEDs destroy information represented in neuronal networks. Cultured neuronal networks are a model for generic cortical microcircuits, and their spontaneous activity is characterized by the presence of synchronized network bursts (SNBs), which share a number of properties with IEDs, including the high degree of synchronization and their spontaneous occurrence in the absence of an external stimulus. As a model approach to understanding the processes underlying IEDs, optogenetic stimulation and multielectrode array (MEA) recordings of cultured neuronal networks were used to study whether stimulus information represented in these networks survives SNBs. When such networks are optically stimulated they encode and maintain stimulus information for as long as one second. Experiments involved recording the network response to a single stimulus and trials where two different stimuli were presented sequentially, akin to a paired pulse trial. We broke the sequential stimulus trials into encoding, delay and readout phases and found that regardless of which phase the SNB occurs, stimulus-specific information was impaired. SNBs were observed to increase the mean network firing rate, but this did not translate monotonically into increases in network entropy. It was found that the more excitable a network, the more stereotyped its response was during a network burst. These measurements speak to whether SNBs are capable of transmitting information in addition to blocking it. These results are consistent with previous reports and provide baseline predictions concerning the neural mechanisms by which IEDs might cause TCI.

  3. Role of glycinergic inhibition in shaping activity of saccadic burst neurons.

    PubMed

    Iwamoto, Yoshiki; Kaneko, Hitoshi; Yoshida, Kaoru; Shimazu, Hiroshi

    2009-06-01

    The immediate premotor signals for saccades are created at the level of medium-lead burst neurons (MLBNs). During fixations, MLBNs receive tonic inhibition from omnipause neurons (OPNs), which use glycine as a neurotransmitter. To elucidate the role of this inhibition, we studied discharge patterns of horizontal MLBNs following iontophoretic application of strychnine, a glycine-receptor antagonist, in alert cats. Three-barrel micropipettes were used for extracellular recording and iontophoresis. After application of strychnine, MLBNs exhibited spontaneous discharge and visual responses during intersaccadic intervals. Spikes were evoked by single-pulse stimulation of the contralateral superior colliculus (SC). These results show that MLBNs receive substantial excitatory input during intersaccadic intervals and that inhibitory action of OPNs is indeed necessary to prevent MLBNs from firing. Strychnine also affected saccade-related activity of MLBNs. The burst of activity, as in normal conditions, declined rapidly before the end of saccades but was followed by low rate spike activity, which continued beyond the end of saccades. This suggests that in normal conditions, the termination of saccades is determined by resumed inhibitory action of OPNs and not by termination of excitatory input to MLBNs. In addition, the firing rate and the number of spikes during saccades increased after strychnine application, suggesting that MLBNs receive glycinergic inhibition of non-OPN origin as well. We conclude that glycinergic inhibition plays essential roles in the maintenance of stable fixation, the termination of saccades, and the regulation of saccade size and velocity.

  4. Increase of dietary vitamin C improves haemocyte respiratory burst response and growth of juvenile grass shrimp, Penaeus monodon, fed with high dietary copper.

    PubMed

    Lee, Min-Hsien; Shiau, Shi-Yen

    2003-04-01

    Effects of dietary vitamin C (l-ascorbyl-2-monophosphate-Mg, C2MP-Mg) on growth, tissue copper (Cu) accumulation, and haemocyte superoxide anion production of juvenile grass shrimp, Penaeus monodon, fed with either adequate or high (8 x adequate) dietary Cu were studied. Three experimental diets were used: basal diet supplemented with adequate levels of both C2MP-Mg (40 mg kg diet(-1)) and Cu (20mg kg diet(-1)) (NC-NCu); basal diet supplemented with adequate C2MP-Mg and high Cu (8 x adequate) (NC-HCu); and basal diet supplemented with high C2MP-Mg (5 x adequate) and high Cu (HC-HCu). These were each fed to triplicate groups of shrimp (mean initial weight: 0.29+/-0.01 g) for 8 weeks. Highest (P< 0.01) weight gain, feed efficiency (FE) and protein efficiency ratio (PER) were observed in shrimp fed NC-NCu diet, intermediate in shrimp fed HC-HCu diet, and lowest in shrimp fed NC-HCu diet. Cu concentrations in hepatopancreas, muscle and haemolymph were highest in shrimp fed NC-HCu diet, followed by shrimp fed HC-HCu diet, and lowest for shrimp fed NC-NCu diet. Survival, total haemocyte count (THC) and intracellular superoxide anion (O-2) production were higher in shrimp fed NC-NCu diet than shrimp fed NC-HCu diet, whereas hepatosomatic index (HSI) was higher in shrimp fed NC-HCu diet than shrimp fed NC-NCu diet. However, all these parameters were similar in shrimp fed NC-NCu diet and shrimp fed HC-HCu diet. These data suggest that increase of dietary vitamin C improved haemocyte respiratory burst response and growth and prevented tissue Cu accumulation in P. monodon fed with high dietary Cu.

  5. A Codimension-2 Bifurcation Controlling Endogenous Bursting Activity and Pulse-Triggered Responses of a Neuron Model

    PubMed Central

    Barnett, William H.; Cymbalyuk, Gennady S.

    2014-01-01

    The dynamics of individual neurons are crucial for producing functional activity in neuronal networks. An open question is how temporal characteristics can be controlled in bursting activity and in transient neuronal responses to synaptic input. Bifurcation theory provides a framework to discover generic mechanisms addressing this question. We present a family of mechanisms organized around a global codimension-2 bifurcation. The cornerstone bifurcation is located at the intersection of the border between bursting and spiking and the border between bursting and silence. These borders correspond to the blue sky catastrophe bifurcation and the saddle-node bifurcation on an invariant circle (SNIC) curves, respectively. The cornerstone bifurcation satisfies the conditions for both the blue sky catastrophe and SNIC. The burst duration and interburst interval increase as the inverse of the square root of the difference between the corresponding bifurcation parameter and its bifurcation value. For a given set of burst duration and interburst interval, one can find the parameter values supporting these temporal characteristics. The cornerstone bifurcation also determines the responses of silent and spiking neurons. In a silent neuron with parameters close to the SNIC, a pulse of current triggers a single burst. In a spiking neuron with parameters close to the blue sky catastrophe, a pulse of current temporarily silences the neuron. These responses are stereotypical: the durations of the transient intervals–the duration of the burst and the duration of latency to spiking–are governed by the inverse-square-root laws. The mechanisms described here could be used to coordinate neuromuscular control in central pattern generators. As proof of principle, we construct small networks that control metachronal-wave motor pattern exhibited in locomotion. This pattern is determined by the phase relations of bursting neurons in a simple central pattern generator modeled by a chain of

  6. Antitussive activity and respiratory system effects of levodropropizine in man.

    PubMed

    Bossi, R; Braga, P C; Centanni, S; Legnani, D; Moavero, N E; Allegra, L

    1988-08-01

    Antitussive activity of the new antitussive drug, levodropropizine (S(-)-3-(4-phenyl-piperazin-1-yl)-propane-1,2-diol, DF 526), was evaluated in healthy volunteers by the classical method of citric acid-induced coughing. Levodropropizine dose-dependently reduced cough frequency. Maximal inhibition was observed at 6 h after administration. Cough intensity was also reduced, as shown by the analysis of cough noise. Levodropropizine, at the dosage of 60 mg t.i.d., had no adverse effects on respiratory function nor on airway clearance mechanisms: in fact, it did not affect spirometric parameters. Levodropropizine had no effects on the rheological properties of mucus nor on ciliary activity of airway epithelium.

  7. Detailed correlation of type III radio bursts with H alpha activity. I - Active region of 22 May 1970.

    NASA Technical Reports Server (NTRS)

    Kuiper, T. B. H.; Pasachoff, J. M.

    1973-01-01

    Comparison of observations of type III impulsive radio bursts made at the Clark Lake Radio Observatory with high-spatial-resolution cinematographic observations taken at the Big Bear Solar Observatory. Use of the log-periodic radio interferometer makes it possible to localize the radio emission uniquely. This study concentrates on the particularly active region close to the limb on May 22, 1970. Sixteen of the 17 groups were associated with some H alpha activity, 11 of them with the start of such activity.

  8. Emerging principles and neural substrates underlying tonic sleep-state-dependent influences on respiratory motor activity.

    PubMed

    Horner, Richard L

    2009-09-12

    Respiratory muscles with dual respiratory and non-respiratory functions (e.g. the pharyngeal and intercostal muscles) show greater suppression of activity in sleep than the diaphragm, a muscle almost entirely devoted to respiratory function. This sleep-related suppression of activity is most apparent in the tonic component of motor activity, which has functional implications of a more collapsible upper airspace in the case of pharyngeal muscles, and decreased functional residual capacity in the case of intercostal muscles. A major source of tonic drive to respiratory motoneurons originates from neurons intimately involved in states of brain arousal, i.e. neurons not classically involved in generating respiratory rhythm and pattern per se. The tonic drive to hypoglossal motoneurons, a respiratory motor pool with both respiratory and non-respiratory functions, is mediated principally by noradrenergic and glutamatergic inputs, these constituting the essential components of the wakefulness stimulus. These tonic excitatory drives are opposed by tonic inhibitory glycinergic and gamma-amino butyric acid (GABA) inputs that constrain the level of respiratory-related motor activity, with the balance determining net motor tone. In sleep, the excitatory inputs are withdrawn and GABA release into the brainstem is increased, thus decreasing respiratory motor tone and predisposing susceptible individuals to hypoventilation and obstructive sleep apnoea.

  9. The 2001 April Burst Activation of SGR 1900+14: Pulse Properties and Torque

    NASA Technical Reports Server (NTRS)

    Woods, P. M.; Kouveliotou, C.; Goegues, E.; Finger, M. H.; Feroci, M.; Mereghetti, S.; Swank, J. H.; Hurley, K.; Heise, J.; Smith, D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We report on observations of SGR 1900+14 made with the Rossi X-ray Timing Explorer (RXTE) and BeppoSAX during the April 2001 burst activation of the source. Using these data, we measure the spindown torque on the star and confirm earlier findings that the torque and burst activity are not directly correlated. We compare the X-ray pulse profile to the gamma-ray profile during the April 18 intermediate flare and show that (i) their shapes are similar and (ii) the gamma-ray profile aligns closely in phase with the X-ray pulsations. The good phase alignment of the gamma-ray and X-ray profiles suggests that there was no rapid spindown following this flare, in contrast to the August 27 giant flare. The absence of rapid spindown in the hours following the April 18 flare suggests that there was no significant outflow of material as was believed to be present following the August 27 flare. Finally, we discuss how these observations further constrain magnetic field reconfiguration models for the large flares of SGRs.

  10. In-vitro activity of sparfloxacin in comparison with currently available antimicrobials against respiratory tract pathogens.

    PubMed

    Baquero, F; Cantón, R

    1996-05-01

    Bacterial resistance to antimicrobial agents is an ever-increasing problem. The in-vitro activity of sparfloxacin compared with that of currently available antimicrobial agents against pathogens implicated in respiratory tract infections is reviewed. Sparfloxacin is a fluoroquinolone active against both penicillin-susceptible and -resistant strains of Streptococcus pneumoniae. It is also active against many other respiratory tract pathogens and may be a suitable alternative for empirical therapy of community-acquired respiratory tract infections.

  11. [Respiratory activity of bacteria Acinetobacter calcoaceticus TM-31 during assimilation of alkane hydrocarbons].

    PubMed

    Ignatov, O V; Grechkina, E V; Muratova, A Iu; Turkovskaia, O V; Ignatov, V V

    2000-01-01

    The respiratory activity of Acinetobacter calcoaceticus TM-31 with resect to alkane hydrocarbons was studied. The dynamics of oxygen consumption by the cells while assimilating n-hexadecane was assayed by a modified technique using an oxygen electrode. The dependence of cell respiratory activity on the amount of n-hexadecane within the concentration range of 0.03-0.66% was determined. It was demonstrated that the cells also displayed respiratory activity towards other medium-chain n-alkanes: hexane, octane, decane, tridecane, and heptadecane. Thus, we demonstrated the possibility of determining alkanes by measuring the respiratory activities of microorganisms.

  12. Immortalized Parkinson's disease lymphocytes have enhanced mitochondrial respiratory activity

    PubMed Central

    Annesley, Sarah J.; Lay, Sui T.; De Piazza, Shawn W.; Sanislav, Oana; Hammersley, Eleanor; Allan, Claire Y.; Francione, Lisa M.; Bui, Minh Q.; Chen, Zhi-Ping; Ngoei, Kevin R. W.; Tassone, Flora; Kemp, Bruce E.; Storey, Elsdon; Evans, Andrew; Loesch, Danuta Z.

    2016-01-01

    ABSTRACT In combination with studies of post-mortem Parkinson's disease (PD) brains, pharmacological and genetic models of PD have suggested that two fundamental interacting cellular processes are impaired – proteostasis and mitochondrial respiration. We have re-examined the role of mitochondrial dysfunction in lymphoblasts isolated from individuals with idiopathic PD and an age-matched control group. As previously reported for various PD cell types, the production of reactive oxygen species (ROS) by PD lymphoblasts was significantly elevated. However, this was not due to an impairment of mitochondrial respiration, as is often assumed. Instead, basal mitochondrial respiration and ATP synthesis are dramatically elevated in PD lymphoblasts. The mitochondrial mass, genome copy number and membrane potential were unaltered, but the expression of indicative respiratory complex proteins was also elevated. This explains the increased oxygen consumption rates by each of the respiratory complexes in experimentally uncoupled mitochondria of iPD cells. However, it was not attributable to increased activity of the stress- and energy-sensing protein kinase AMPK, a regulator of mitochondrial biogenesis and activity. The respiratory differences between iPD and control cells were sufficiently dramatic as to provide a potentially sensitive and reliable biomarker of the disease state, unaffected by disease duration (time since diagnosis) or clinical severity. Lymphoblasts from control and PD individuals thus occupy two distinct, quasi-stable steady states; a ‘normal’ and a ‘hyperactive’ state characterized by two different metabolic rates. The apparent stability of the ‘hyperactive’ state in patient-derived lymphoblasts in the face of patient ageing, ongoing disease and mounting disease severity suggests an early, permanent switch to an alternative metabolic steady state. With its associated, elevated ROS production, the ‘hyperactive’ state might not cause pathology

  13. Large Scale Cortical Functional Networks Associated with Slow-Wave and Spindle-Burst-Related Spontaneous Activity

    PubMed Central

    McVea, David A.; Murphy, Timothy H.; Mohajerani, Majid H.

    2016-01-01

    Cortical sensory systems are active with rich patterns of activity during sleep and under light anesthesia. Remarkably, this activity shares many characteristics with those present when the awake brain responds to sensory stimuli. We review two specific forms of such activity: slow-wave activity (SWA) in the adult brain and spindle bursts in developing brain. SWA is composed of 0.5–4 Hz resting potential fluctuations. Although these fluctuations synchronize wide regions of cortex, recent large-scale imaging has shown spatial details of their distribution that reflect underlying cortical structural projections and networks. These networks are regulated, as prior awake experiences alter both the spatial and temporal features of SWA in subsequent sleep. Activity patterns of the immature brain, however, are very different from those of the adult. SWA is absent, and the dominant pattern is spindle bursts, intermittent high frequency oscillations superimposed on slower depolarizations within sensory cortices. These bursts are driven by intrinsic brain activity, which act to generate peripheral inputs, for example via limb twitches. They are present within developing sensory cortex before they are mature enough to exhibit directed movements and respond to external stimuli. Like in the adult, these patterns resemble those evoked by sensory stimulation when awake. It is suggested that spindle-burst activity is generated purposefully by the developing nervous system as a proxy for true external stimuli. While the sleep-related functions of both slow-wave and spindle-burst activity may not be entirely clear, they reflect robust regulated phenomena which can engage select wide-spread cortical circuits. These circuits are similar to those activated during sensory processing and volitional events. We highlight these two patterns of brain activity because both are prominent and well-studied forms of spontaneous activity that will yield valuable insights into brain function in

  14. How Long does a Burst Burst?

    NASA Astrophysics Data System (ADS)

    Zhang, Bin-Bin; Zhang, Bing; Murase, Kohta; Connaughton, Valerie; Briggs, Michael S.

    2014-05-01

    Several gamma-ray bursts (GRBs) last much longer (~hours) in γ-rays than typical long GRBs (~minutes), and it has recently been proposed that these "ultra-long GRBs" may form a distinct population, probably with a different (e.g., blue supergiant) progenitor than typical GRBs. However, Swift observations suggest that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with X-Ray Telescope observations to investigate GRB central engine activity duration and to determine whether ultra-long GRBs are unusual events. We define burst duration t burst based on both γ-ray and X-ray light curves rather than using γ-ray observations alone. We find that t burst can be reliably measured in 343 GRBs. Within this "good" sample, 21.9% GRBs have t burst >~ 103 s and 11.5% GRBs have t burst >~ 104 s. There is an apparent bimodal distribution of t burst in this sample. However, when we consider an "undetermined" sample (304 GRBs) with t burst possibly falling in the gap between GRB duration T 90 and the first X-ray observational time, as well as a selection effect against t burst falling into the first Swift orbital "dead zone" due to observation constraints, the intrinsic underlying t burst distribution is consistent with being a single component distribution. We found that the existing evidence for a separate ultra-long GRB population is inconclusive, and further multi-wavelength observations are needed to draw a firmer conclusion. We also discuss the theoretical implications of our results. In particular, the central engine activity duration of GRBs is generally much longer than the γ-ray T 90 duration and it does not even correlate with T 90. It would be premature to make a direct connection between T 90 and the size of the progenitor star.

  15. Cerebellar theta burst stimulation modulates the neural activity of interconnected parietal and motor areas

    PubMed Central

    Casula, Elias Paolo; Pellicciari, Maria Concetta; Ponzo, Viviana; Stampanoni Bassi, Mario; Veniero, Domenica; Caltagirone, Carlo; Koch, Giacomo

    2016-01-01

    Voluntary movement control and execution are regulated by the influence of the cerebellar output over different interconnected cortical areas, through dentato-thalamo connections. In the present study we applied transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess the effects of cerebellar theta-burst stimulation (TBS) over the controlateral primary motor cortex (M1) and posterior parietal cortex (PPC) in a group of healthy volunteers. We found a TBS-dependent bidirectional modulation over TMS-evoked activity; specifically, cTBS increased whereas iTBS decreased activity between 100 and 200 ms after TMS, in a similar manner over both M1 and PPC areas. On the oscillatory domain, TBS induced specific changes over M1 natural frequencies of oscillation: TMS-evoked alpha activity was decreased by cTBS whereas beta activity was enhanced by iTBS. No effects were observed after sham stimulation. Our data provide novel evidence showing that the cerebellum exerts its control on the cortex likely by impinging on specific set of interneurons dependent on GABA-ergic activity. We show that cerebellar TBS modulates cortical excitability of distant interconnected cortical areas by acting through common temporal, spatial and frequency domains. PMID:27796359

  16. Adenosine promotes burst activity in guinea-pig geniculocortical neurones through two different ionic mechanisms.

    PubMed Central

    Pape, H C

    1992-01-01

    -mediated burst discharges, and (ii) the decrease in Ih inhibited the dampening effect on Ca(2+)-mediated rebound activity of beta-adrenergic receptor stimulation. 7. It is suggested that during increased levels of extracellular adenosine the response of LGND relay neurones to activating brainstem influences will be depressed, and a pattern of Ca(2+)-mediated burst firing will be favoured. PMID:1593463

  17. 76 FR 28460 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Rock Burst...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-17

    ...; Rock Burst Control Plan--Pertains to Underground Metal and Nonmetal Mines ACTION: Notice. SUMMARY: The... information collection request (ICR) titled, ``Burst Control Plan--Pertains to Underground Metal and Nonmetal... INFORMATION: Regulations 30 CFR 57.3461 requires underground metal and nonmetal mine operators to develop...

  18. Effect of short burst activities on sprint and agility performance in 11- to 12-year-old boys.

    PubMed

    Pettersen, Svein A; Mathisen, Gunnar E

    2012-04-01

    There are limited data on how coordinative sprint drills and maximal short burst activities affects children's sprint and agility performance. The purpose of the present study was to investigate the effect of short burst activities on sprint and agility performance in 11- to 12-year-old boys. A training group (TG) of 14 boys followed a 6-week, 1-hour·week(-1), training program consisting of different short burst competitive sprinting activities. Eleven boys of similar age served as controls (control group [CG]). Pre- and posttests assessed 10-m sprint, 20-m sprint, and agility performance. Results revealed significant performance improvement in all tests within TG (p < 0.05), but not between TG and CG in the 10-m sprint test. Furthermore, the relationships between the performances in straight-line sprint and agility showed a significant transfer effect (r = 0.68-0.75, p < 0.001). Findings from the present study indicate that competitive short burst activities executed with maximal effort may produce improvement in sprint and agility performance in 11- to 12-year-old boys.

  19. Matrix Metalloproteinase 9 Exerts Antiviral Activity against Respiratory Syncytial Virus

    PubMed Central

    Dabo, Abdoulaye J.; Cummins, Neville; Eden, Edward; Geraghty, Patrick

    2015-01-01

    Increased lung levels of matrix metalloproteinase 9 (MMP9) are frequently observed during respiratory syncytial virus (RSV) infection and elevated MMP9 concentrations are associated with severe disease. However little is known of the functional role of MMP9 during lung infection with RSV. To determine whether MMP9 exerted direct antiviral potential, active MMP9 was incubated with RSV, which showed that MMP9 directly prevented RSV infectivity to airway epithelial cells. Using knockout mice the effect of the loss of Mmp9 expression was examined during RSV infection to demonstrate MMP9’s role in viral clearance and disease progression. Seven days following RSV infection, Mmp9-/- mice displayed substantial weight loss, increased RSV-induced airway hyperresponsiveness (AHR) and reduced clearance of RSV from the lungs compared to wild type mice. Although total bronchoalveolar lavage fluid (BALF) cell counts were similar in both groups, neutrophil recruitment to the lungs during RSV infection was significantly reduced in Mmp9-/- mice. Reduced neutrophil recruitment coincided with diminished RANTES, IL-1β, SCF, G-CSF expression and p38 phosphorylation. Induction of p38 signaling was required for RANTES and G-CSF expression during RSV infection in airway epithelial cells. Therefore, MMP9 in RSV lung infection significantly enhances neutrophil recruitment, cytokine production and viral clearance while reducing AHR. PMID:26284919

  20. Na(+)/K(+) pump interacts with the h-current to control bursting activity in central pattern generator neurons of leeches.

    PubMed

    Kueh, Daniel; Barnett, William H; Cymbalyuk, Gennady S; Calabrese, Ronald L

    2016-09-02

    The dynamics of different ionic currents shape the bursting activity of neurons and networks that control motor output. Despite being ubiquitous in all animal cells, the contribution of the Na(+)/K(+) pump current to such bursting activity has not been well studied. We used monensin, a Na(+)/H(+) antiporter, to examine the role of the pump on the bursting activity of oscillator heart interneurons in leeches. When we stimulated the pump with monensin, the period of these neurons decreased significantly, an effect that was prevented or reversed when the h-current was blocked by Cs(+). The decreased period could also occur if the pump was inhibited with strophanthidin or K(+)-free saline. Our monensin results were reproduced in model, which explains the pump's contributions to bursting activity based on Na(+) dynamics. Our results indicate that a dynamically oscillating pump current that interacts with the h-current can regulate the bursting activity of neurons and networks.

  1. Reconfiguration of respiratory-related population activity in a rostrally tilted transversal slice preparation following blockade of inhibitory neurotransmission in neonatal rats.

    PubMed

    Funke, Frank; Müller, Michael; Dutschmann, Mathias

    2008-10-01

    Recent studies showed that respiratory rhythm generation depends on oscillators located in the pre-Bötzinger complex (pre-BötC) and the parafacial respiratory group (pFRG). To study inhibitory synaptic interactions between these two oscillators, we developed a rostrally tilted transversal slice preparation, which preserves these regions. The onset of rhythmic mass activity in the retrotrapezoid nucleus (RTN)/pFRG preceded that of the pre-BötC. Blockade of glycinergic and gamma-aminobutyric acidic inhibition synchronized pre-BötC and RTN/pFRG activity and significantly increased pre-BötC burst frequency, amplitude, and duration. Population imaging revealed recruitment of inspiratory-like neurones, while expiratory-like neurones lost their phasic activity. The reconfiguration after disinhibition reveals: (1) synaptic inhibition of the pre-BötC arising from the RTN/pFRG, (2) excitatory drive from the RTN/pFRG that triggers the pre-BötC burst. Our findings support the view that these synaptic interactions in vitro relate to the initiation of the inspiratory phase or to the steering of the expiratory-inspiratory phase transition in vivo.

  2. Emergency department syndromic surveillance providing early warning of seasonal respiratory activity in England.

    PubMed

    Hughes, H E; Morbey, R; Hughes, T C; Locker, T E; Pebody, R; Green, H K; Ellis, J; Smith, G E; Elliot, A J

    2016-04-01

    Seasonal respiratory infections place an increased burden on health services annually. We used a sentinel emergency department syndromic surveillance system to understand the factors driving respiratory attendances at emergency departments (EDs) in England. Trends in different respiratory indicators were observed to peak at different points during winter, with further variation observed in the distribution of attendances by age. Multiple linear regression analysis revealed acute respiratory infection and bronchitis/bronchiolitis ED attendances in patients aged 1-4 years were particularly sensitive indicators for increasing respiratory syncytial virus activity. Using near real-time surveillance of respiratory ED attendances may provide early warning of increased winter pressures in EDs, particularly driven by seasonal pathogens. This surveillance may provide additional intelligence about different categories of attendance, highlighting pressures in particular age groups, thereby aiding planning and preparation to respond to acute changes in EDs, and thus the health service in general.

  3. In vitro visualization of respiratory neuron activity in the newborn mouse ventral medulla.

    PubMed

    Onimaru, Hiroshi; Arata, Akiko; Arata, Satoru; Shirasawa, Senji; Cleary, Michael L

    2004-11-25

    To clarify the neuronal organization of the respiratory center of the mouse, we analyzed the spatio-temporal pattern of respiratory neuron activity in the ventral medulla of a newborn mouse preparation, using optical recordings. We also demonstrated optical images of the respiratory activity of two different lines of knock-out mice (Tlx3-/-, Pbx3-/-) that exhibit respiratory failure leading to neonatal death from dysfunction of central respiratory neuron activity. In the wild type mice, the respiratory neuron activity in the para-facial region of the rostral medulla appeared prior to inspiratory activity in the more caudal ventrolateral medulla. This rostral to caudal activity pattern was basically preserved in Tlx3-/- mice though the activity was more dispersed and weaker than in the wild type mice. Such an activity pattern was not clearly detected in Pbx3-/- mouse preparations. The difference in the spatio-temporal pattern between Tlx3-/- and Pbx3-/- suggests different levels of functional disorder of the respiratory center.

  4. UNUSUAL CENTRAL ENGINE ACTIVITY IN THE DOUBLE BURST GRB 110709B

    SciTech Connect

    Zhang Binbin; Burrows, David N.; Meszaros, Peter; Falcone, Abraham D.; Zhang Bing; Wang Xiangyu; Stratta, Giulia; D'Elia, Valerio; Frederiks, Dmitry; Golenetskii, Sergey; Cummings, Jay R.; Barthelmy, Scott D.; Gehrels, Neil; Norris, Jay P.

    2012-04-01

    The double burst, GRB 110709B, triggered the Swift/Burst Alert Telescope (BAT) twice at 21:32:39 UT and 21:43:45 UT, respectively, on 2011 July 9. This is the first time we observed a gamma-ray burst (GRB) with two BAT triggers. In this paper, we present simultaneous Swift and Konus-WIND observations of this unusual GRB and its afterglow. If the two events originated from the same physical progenitor, their different time-dependent spectral evolution suggests they must belong to different episodes of the central engine, which may be a magnetar-to-BH accretion system.

  5. Variable Spin-Down in the Soft Gamma Repeater SGR 1900+14 and Correlations with Burst Activity

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; vanParadijs, Jan; Finger, Mark H.; Thompson, Christopher; Duncan, Robert C.; Hurley, Kevin; Swank, Jean; Murakami, Toshio

    1999-01-01

    We have analyzed Rossi X-ray Timing Explorer Proportional Counter Array observation of the pulsed emission from SGR 1900+14 during September 1996, June-October 1998, and early 1999. Using these measurements and results reported elsewhere. we construct a period history of this source for 2.5 years. We find significant deviations from a steady spin-down trend during quiescence and the burst active interval. Burst And Transient Source Experiment (BATSE) observations of the burst emission are presented and correlations between the burst activity and spin-down rate of SGR 1900 + 14 are discussed. We find an 80 day interval during the summer of 1998 when the average spin-down rate is larger than the rate elsewhere by a factor of about 2.3. This enhanced spin-down may, be the result of a discontinuous spin-down event or "braking glitch" at the time of the giant flare on 27 August 1998. Furthermore find a large discrepancy between the pulsar period and average spin-down rate in X-rays as compared to radio observation for December 1998 and January 1999.

  6. Variable Spin-Down in the Soft Gamma Repeater SGR 1900+14 and Correlations with Burst Activity

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; VanParadijs, Jan; Finger, Mark H.; Thompson, Christopher; Duncan, Robert C.; Hurley, Kevin; Strohmayer, Tod; Swank, Jean; Murakami, Toshio

    1999-01-01

    We have analyzed Rossi X-ray Timing Explorer Proportional Counter Array observations of the pulsed emission from SGR 1900+ 14 during 1996 September, 1998 June-October, and early 1999. Using these measurements and results reported elsewhere, we construct a period history of this source for 2.5 yr. We find significant deviations from a steady spin-down trend during quiescence and the burst active interval. Burst and Transient Source Experiment observations of the burst emission are presented and correlations between the burst activity and spin-down rate of SGR 1900+14 are discussed. We find an 80 day interval during the summer of 1998 when the average spin-down rate is larger than the rate elsewhere by a factor approximately 2.3. This enhanced spin-down may be the result of a discontinuous spin-down event or "braking glitch" at the time of the giant flare on 1998 August 27. Furthermore, we find a large discrepancy between the pulsar period and average spin-down rate in X-rays as compared to radio observations for 1998 December and 1999 January.

  7. Substituted benzimidazoles with nanomolar activity against respiratory syncytial virus.

    PubMed

    Andries, Koen; Moeremans, Marc; Gevers, Tom; Willebrords, Rudy; Sommen, Cois; Lacrampe, Jean; Janssens, Frans; Wyde, Philip R

    2003-11-01

    A cell-based assay was used to discover compounds inhibiting respiratory syncytial virus (RSV)-induced fusion in HeLa/M cells. A lead compound was identified and subsequent synthesis of >300 analogues led to the identification of JNJ 2408068 (R170591), a low molecular weight (MW 395) benzimidazole derivative with an EC(50) (0.16 nM) against some lab strains almost 100,000 times better than that of ribavirin (15 microM). Antiviral activity was confirmed for subgroup A and B clinical isolates of human RSV and for a bovine RSV isolate. The compound did not inhibit the growth of representative viruses from other Paramyxovirus genera, i.e. HPIV2 and Mumps Virus (genus Rubulavirus), HPIV3 (genus Respirovirus), Measles virus (genus Morbillivirus) and hMPV. Efficacy in cytopathic effect inhibition assays correlated well with efficacy in virus yield reduction assays. A concentration of 10nM reduced RSV production 1000-fold in multi-cycle experiments, irrespective of the multiplicity of infection. Time of addition studies pointed to a dual mode of action: inhibition of virus-cell fusion early in the infection cycle and inhibition of cell-cell fusion at the end of the replication cycle. Two resistant mutants were raised and shown to have single point mutations in the F-gene (S398L and D486N). JNJ 2408068 was also shown to inhibit the release of proinflammatory cytokines IL-6, IL-8 and Rantes from RSV-infected A549 cells.

  8. Activation of metabotropic glutamate 5 and NMDA receptors underlies the induction of persistent bursting and associated long-lasting changes in CA3 recurrent connections.

    PubMed

    Stoop, Ron; Conquet, François; Zuber, Benoit; Voronin, Leon L; Pralong, Etienne

    2003-07-02

    The aim of this study was to describe the induction and expression mechanisms of a persistent bursting activity in a horizontal slice preparation of the rat limbic system that includes the ventral part of the hippocampus and the entorhinal cortex. Disinhibition of this preparation by bicuculline led to interictal-like bursts in the CA3 region that triggered synchronous activity in the entorhinal cortex. Washout of bicuculline after a 1 hr application resulted in a maintained production of hippocampal bursts that continued to spread to the entorhinal cortex. Separation of CA3 from the entorhinal cortex caused the activity in the latter to become asynchronous with CA3 activity in the presence of bicuculline and disappear after washout; however, in CA3, neither the induction of bursting nor its persistence were affected. Associated with the CA3 persistent bursting, a strengthening of recurrent collateral excitatory input to CA3 pyramidal cells and a decreased input to CA3 interneurons was found. Both the induction of the persistent bursting and the changes in synaptic strength were prevented by antagonists of metabotropic glutamate 5 (mGlu5) or NMDA receptors or protein synthesis inhibitors and did not occur in slices from mGlu5 receptor knock-out mice. The above findings suggest potential synaptic mechanisms by which the hippocampus switches to a persistent interictal bursting mode that may support a spread of interictal-like bursting to surrounding temporal lobe regions.

  9. Influence of age and sex on the pressor response following a spontaneous burst of muscle sympathetic nerve activity

    PubMed Central

    Vianna, Lauro C.; Hart, Emma C.; Fairfax, Seth T.; Charkoudian, Nisha; Joyner, Michael J.

    2012-01-01

    The sympathetic nervous system is critical for the beat-to-beat regulation of arterial blood pressure (BP). Although studies have examined age- and sex-related effects on BP control, findings are inconsistent and limited data are available in postmenopausal women. In addition, the majority of studies have focused on time-averaged responses without consideration for potential beat-to-beat alterations. Thus we examined whether the ability of muscle sympathetic nerve activity (MSNA) to modulate BP on a beat-to-beat basis is affected by age or sex. BP and MSNA were measured during supine rest in 40 young (20 men) and 40 older (20 men) healthy subjects. Beat-to-beat fluctuations in mean arterial pressure (MAP) were characterized for 15 cardiac cycles after each MSNA burst using signal averaging. The rise in MAP following an MSNA burst was similar between young men and women (+2.64 ± 0.3 vs. +2.57 ± 0.3 mmHg, respectively). However, the magnitude of the increase in MAP after an MSNA burst was reduced in older compared with young subjects (P < 0.05). Moreover, the attenuation of the pressor response was greater in older women (+1.20 ± 0.1 mmHg) compared with older men (+1.72 ± 0.2 mmHg; P < 0.05). Interestingly, in all groups, MAP consistently decreased after cardiac cycles without MSNA bursts (nonbursts) with the magnitude of fall greatest in older men. In summary, healthy aging is associated with an attenuated beat-to-beat increase in BP after a spontaneous MSNA burst, and this attenuation is more pronounced in postmenopausal women. Furthermore, our nonburst findings highlight the importance of sympathetic vasoconstrictor activity to maintain beat-to-beat BP, particularly in older men. PMID:22427525

  10. Reduced respiratory neural activity elicits a long-lasting decrease in the CO2 threshold for apnea in anesthetized rats.

    PubMed

    Baertsch, N A; Baker, T L

    2017-01-01

    Two critical parameters that influence breathing stability are the levels of arterial pCO2 at which breathing ceases and subsequently resumes - termed the apneic and recruitment thresholds (AT and RT, respectively). Reduced respiratory neural activity elicits a chemoreflex-independent, long-lasting increase in phrenic burst amplitude, a form of plasticity known as inactivity-induced phrenic motor facilitation (iPMF). The physiological significance of iPMF is unknown. To determine if iPMF and neural apnea have long-lasting physiological effects on breathing, we tested the hypothesis that patterns of neural apnea that induce iPMF also elicit changes in the AT and RT. Phrenic nerve activity and end-tidal CO2 were recorded in urethane-anesthetized, ventilated rats to quantify phrenic nerve burst amplitude and the AT and RT before and after three patterns of neural apnea that differed in their duration and ability to elicit iPMF: brief intermittent neural apneas, a single brief "massed" neural apnea, or a prolonged neural apnea. Consistent with our hypothesis, we found that patterns of neural apnea that elicited iPMF also resulted in changes in the AT and RT. Specifically, intermittent neural apneas progressively decreased the AT with each subsequent neural apnea, which persisted for at least 60min. Similarly, a prolonged neural apnea elicited a long-lasting decrease in the AT. In both cases, the magnitude of the AT decrease was proportional to iPMF. In contrast, the RT was transiently decreased following prolonged neural apnea, and was not proportional to iPMF. No changes in the AT or RT were observed following a single brief neural apnea. Our results indicate that the AT and RT are differentially altered by neural apnea and suggest that specific patterns of neural apnea that elicit plasticity may stabilize breathing via a decrease in the AT.

  11. Activation of respiratory muscles does not occur during cold-submergence in bullfrogs, Lithobates catesbeianus.

    PubMed

    Santin, Joseph M; Hartzler, Lynn K

    2017-01-17

    Semiaquatic frogs may not breathe air for several months because they overwinter in ice-covered ponds. In contrast to many vertebrates that experience decreased motor performance after inactivity, respiratory motor function in bullfrogs, Lithobates catesbeianus, remains functional following cold-submergence. Unlike mammalian hibernators with unloaded limb muscles and inactive locomotor systems, respiratory mechanics of frogs counterintuitively allow for ventilatory maneuvers when submerged. Thus we hypothesized that bullfrogs generate respiratory motor patterns during cold-submergence to avoid disuse and preserve motor performance. Accordingly, we measured activity of respiratory muscles (buccal floor compressor and glottal dilator) via electromyography in freely behaving bullfrogs at 20°C and 2°C. Although we confirm that ventilation cycles occur underwater at 20°C, bullfrogs did not activate either respiratory muscle when submerged acutely or chronically at 2°C. We conclude that cold-submerged bullfrogs endure respiratory motor inactivity, implying that other mechanisms, excluding underwater muscle activation, maintain a functional respiratory motor system throughout overwintering.

  12. Theta-Burst LTP

    PubMed Central

    Larson, John; Munkácsy, Erin

    2014-01-01

    This review covers the spatial and temporal rules governing induction of hippocampal long-term potentiation (LTP) by theta-burst stimulation. Induction of LTP in field CA1 by high frequency stimulation bursts that resemble the burst discharges (complex-spikes) of hippocampal pyramidal neurons involves a multiple-step mechanism. A single burst is insufficient for LTP induction because it evokes both excitatory and inhibitory currents that partially cancel and limit postsynaptic depolarization. Bursts repeated at the frequency (~5 Hz) of the endogenous theta rhythm induce maximal LTP, primarily because this frequency disables feed-forward inhibition and allows sufficient postsynaptic depolarization to activate voltage-sensitive NMDA receptors. The disinhibitory process, referred to as “priming”, involves presynaptic GABA autoreceptors that inhibit GABA release. Activation of NMDA receptors allows a calcium flux into dendritic spines that serves as the proximal trigger for LTP. We include new data showing that theta-burst stimulation is more efficient than other forms of stimulation for LTP induction. In addityion, we demonstrate that associative interactions between synapses activated during theta-bursts are limited to major dendritic domains since such interactions occur within apical or basal dendritic trees but not between them. We review evidence that recordings of electrophysiological responses during theta burst stimulation can help to determine if experimental manipulations that affect LTP do so by affecting events antecedent to the induction process, such as NMDA receptor activation, or downstream signaling cascades that result from postsynaptic calcium fluxes. Finally, we argue that theta-burst LTP represents a minimal model for stable, non-decremental LTP that is more sensitive to a variety of experimental manipulations than is LTP induced by other stimulation paradigms. PMID:25452022

  13. EGFR activation suppresses respiratory virus-induced IRF1-dependent CXCL10 production.

    PubMed

    Kalinowski, April; Ueki, Iris; Min-Oo, Gundula; Ballon-Landa, Eric; Knoff, David; Galen, Benjamin; Lanier, Lewis L; Nadel, Jay A; Koff, Jonathan L

    2014-07-15

    Airway epithelial cells are the primary cell type involved in respiratory viral infection. Upon infection, airway epithelium plays a critical role in host defense against viral infection by contributing to innate and adaptive immune responses. Influenza A virus, rhinovirus, and respiratory syncytial virus (RSV) represent a broad range of human viral pathogens that cause viral pneumonia and induce exacerbations of asthma and chronic obstructive pulmonary disease. These respiratory viruses induce airway epithelial production of IL-8, which involves epidermal growth factor receptor (EGFR) activation. EGFR activation involves an integrated signaling pathway that includes NADPH oxidase activation of metalloproteinase, and EGFR proligand release that activates EGFR. Because respiratory viruses have been shown to activate EGFR via this signaling pathway in airway epithelium, we investigated the effect of virus-induced EGFR activation on airway epithelial antiviral responses. CXCL10, a chemokine produced by airway epithelial cells in response to respiratory viral infection, contributes to the recruitment of lymphocytes to target and kill virus-infected cells. While respiratory viruses activate EGFR, the interaction between CXCL10 and EGFR signaling pathways is unclear, and the potential for EGFR signaling to suppress CXCL10 has not been explored. Here, we report that respiratory virus-induced EGFR activation suppresses CXCL10 production. We found that influenza virus-, rhinovirus-, and RSV-induced EGFR activation suppressed IFN regulatory factor (IRF) 1-dependent CXCL10 production. In addition, inhibition of EGFR during viral infection augmented IRF1 and CXCL10. These findings describe a novel mechanism that viruses use to suppress endogenous antiviral defenses, and provide potential targets for future therapies.

  14. EGFR activation suppresses respiratory virus-induced IRF1-dependent CXCL10 production

    PubMed Central

    Kalinowski, April; Ueki, Iris; Min-Oo, Gundula; Ballon-Landa, Eric; Knoff, David; Galen, Benjamin; Lanier, Lewis L.; Nadel, Jay A.

    2014-01-01

    Airway epithelial cells are the primary cell type involved in respiratory viral infection. Upon infection, airway epithelium plays a critical role in host defense against viral infection by contributing to innate and adaptive immune responses. Influenza A virus, rhinovirus, and respiratory syncytial virus (RSV) represent a broad range of human viral pathogens that cause viral pneumonia and induce exacerbations of asthma and chronic obstructive pulmonary disease. These respiratory viruses induce airway epithelial production of IL-8, which involves epidermal growth factor receptor (EGFR) activation. EGFR activation involves an integrated signaling pathway that includes NADPH oxidase activation of metalloproteinase, and EGFR proligand release that activates EGFR. Because respiratory viruses have been shown to activate EGFR via this signaling pathway in airway epithelium, we investigated the effect of virus-induced EGFR activation on airway epithelial antiviral responses. CXCL10, a chemokine produced by airway epithelial cells in response to respiratory viral infection, contributes to the recruitment of lymphocytes to target and kill virus-infected cells. While respiratory viruses activate EGFR, the interaction between CXCL10 and EGFR signaling pathways is unclear, and the potential for EGFR signaling to suppress CXCL10 has not been explored. Here, we report that respiratory virus-induced EGFR activation suppresses CXCL10 production. We found that influenza virus-, rhinovirus-, and RSV-induced EGFR activation suppressed IFN regulatory factor (IRF) 1-dependent CXCL10 production. In addition, inhibition of EGFR during viral infection augmented IRF1 and CXCL10. These findings describe a novel mechanism that viruses use to suppress endogenous antiviral defenses, and provide potential targets for future therapies. PMID:24838750

  15. A closed-loop model of the respiratory system: focus on hypercapnia and active expiration.

    PubMed

    Molkov, Yaroslav I; Shevtsova, Natalia A; Park, Choongseok; Ben-Tal, Alona; Smith, Jeffrey C; Rubin, Jonathan E; Rybak, Ilya A

    2014-01-01

    Breathing is a vital process providing the exchange of gases between the lungs and atmosphere. During quiet breathing, pumping air from the lungs is mostly performed by contraction of the diaphragm during inspiration, and muscle contraction during expiration does not play a significant role in ventilation. In contrast, during intense exercise or severe hypercapnia forced or active expiration occurs in which the abdominal "expiratory" muscles become actively involved in breathing. The mechanisms of this transition remain unknown. To study these mechanisms, we developed a computational model of the closed-loop respiratory system that describes the brainstem respiratory network controlling the pulmonary subsystem representing lung biomechanics and gas (O2 and CO2) exchange and transport. The lung subsystem provides two types of feedback to the neural subsystem: a mechanical one from pulmonary stretch receptors and a chemical one from central chemoreceptors. The neural component of the model simulates the respiratory network that includes several interacting respiratory neuron types within the Bötzinger and pre-Bötzinger complexes, as well as the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) representing the central chemoreception module targeted by chemical feedback. The RTN/pFRG compartment contains an independent neural generator that is activated at an increased CO2 level and controls the abdominal motor output. The lung volume is controlled by two pumps, a major one driven by the diaphragm and an additional one activated by abdominal muscles and involved in active expiration. The model represents the first attempt to model the transition from quiet breathing to breathing with active expiration. The model suggests that the closed-loop respiratory control system switches to active expiration via a quantal acceleration of expiratory activity, when increases in breathing rate and phrenic amplitude no longer provide sufficient ventilation. The model

  16. Respiratory Sinus Arrhythmia as an Index of Vagal Activity during Stress in Infants: Respiratory Influences and Their Control

    PubMed Central

    Ritz, Thomas; Bosquet Enlow, Michelle; Schulz, Stefan M.; Kitts, Robert; Staudenmayer, John; Wright, Rosalind J.

    2012-01-01

    Respiratory sinus arrhythmia (RSA) is related to cardiac vagal outflow and the respiratory pattern. Prior infant studies have not systematically examined respiration rate and tidal volume influences on infant RSA or the extent to which infants' breathing is too fast to extract a valid RSA. We therefore monitored cardiac activity, respiration, and physical activity in 23 six-month old infants during a standardized laboratory stressor protocol. On average, 12.6% (range 0–58.2%) of analyzed breaths were too short for RSA extraction. Higher respiration rate was associated with lower RSA amplitude in most infants, and lower tidal volume was associated with lower RSA amplitude in some infants. RSA amplitude corrected for respiration rate and tidal volume influences showed theoretically expected strong reductions during stress, whereas performance of uncorrected RSA was less consistent. We conclude that stress-induced changes of peak-valley RSA and effects of variations in breathing patterns on RSA can be determined for a representative percentage of infant breaths. As expected, breathing substantially affects infant RSA and needs to be considered in studies of infant psychophysiology. PMID:23300753

  17. New burst of the active symbiotic star BF Cyg at the beginning of 2017.

    NASA Astrophysics Data System (ADS)

    Skopal, A.; Sekeras, M.; Shugarov, S.; Shagatova, N.

    2017-02-01

    BF Cyg is an eclipsing symbiotic binary with the orbital period of 757 d. Historical light curve of BF Cyg shows a slow symbiotic-nova-like outburst (1895-1960) with superposed eruptions of the Z And type and bursts on the time scale of, or less than, one year (e.g.

  18. FAST OPTICAL VARIABILITY OF A NAKED-EYE BURST-MANIFESTATION OF THE PERIODIC ACTIVITY OF AN INTERNAL ENGINE

    SciTech Connect

    Beskin, G.; Karpov, S.; Bondar, S.; Greco, G.; Guarnieri, A.; Bartolini, C.; Piccioni, A.

    2010-08-10

    We imaged the position of the naked-eye burst, GRB080319B, before, during, and after its gamma-ray activity with sub-second temporal resolution using the TORTORA wide-field camera. The burst optical prompt emission, which reached 5.3 mag, has been detected, and its periodic optical variability has been discovered in the form of four equidistant flashes with a duration of several seconds. We also detected a strong correlation (r {approx} 0.82) between optical and gamma-ray light curves with a 2 s delay of the optical emission with respect to the gamma-ray emission. The revealed temporal structure of the optical light curve in comparison with the gamma-ray light curve can be interpreted in the framework of the model of shell collisions in the ejecta containing a significant neutron component. All observed emission features reflect the non-stationary behavior of the burst internal engine-supposedly, a hyperaccreting solar-mass black hole formed in the collapse of a massive stellar core.

  19. Patterns of brain activity in response to respiratory stimulation in patients with idiopathic hyperventilation (IHV).

    PubMed

    Jack, S; Kemp, G J; Bimson, W E; Calverley, P M A; Corfield, D R

    2010-01-01

    Dyspnoea, usually defined as an uncomfortable awareness of breathing, is one of the most frequent and distressing symptoms experienced by patients with lung disease. Idiopathic hyperventilation (IHV) has unknown aetiology and little is known about the mechanisms that cause the characteristic sustained hypocapnia and chronic dyspnoea. We have shown in IHV and other chronic respiratory disorders that air hunger is the dominant sensation during exercise, while resting breathlessness is characterised by an affective component. The increased drive to breathe in IHV, and indeed dyspnoea in all chronic respiratory disorders, might be better understood if the central mechanisms of dyspnoea were known. The aim of the present study was to characterise the cortical processing of respiratory-related sensory inputs in patients with IHV. Four patients with IHV were studied with ethical approval. Respiratory stimulation was produced using transient occlusion of inspiration (TIO) during spontaneous breathing (delivered in early inspiration with duration c. 300 ms; this is well tolerated) while BOLD fMRI was performed on a 3 Tesla Siemens Trio. TIO was associated with significant activation in sensorimotor and pre-motor cortical areas and the cerebellum, notably the anterior insula, an area previously associated with breathlessness in healthy volunteers. These preliminary observations on the pattern of brain activity in response to respiratory stimulation support the hypothesis that breathlessness in IHV may reflect inappropriate cortical processing of respiratory-related sensory inputs.

  20. Flowers of Clerodendrum volubile exacerbate immunomodulation by suppressing phagocytic oxidative burst and modulation of COX-2 activity.

    PubMed

    Erukainure, Ochuko L; Mesaik, Ahmed M; Muhammad, Aliyu; Chukwuma, Chika I; Manhas, Neha; Singh, Parvesh; Aremu, Oluwole S; Islam, Md Shahidul

    2016-10-01

    The immunomodulatory potentials of the crude methanolic extract and fractions [n-hexane (Hex), n-dichloromethane (DCM), ethyl acetate (EtOAc) and n-butanol (BuOH)] of Clerodendrum volubile flowers were investigated on whole blood phagocytic oxidative burst using luminol-amplified chemiluminescence technique. They were also investigated for their free radicals scavenging activities. The DCM fraction showed significant (p<0.05) anti-oxidative burst and free radical scavenging activities indicating high immunomodulatory and antioxidant potencies respectively. Cytotoxicity assay of the DCM fraction revealed a cytotoxic effect on CC-1 normal cell line. GCMS analysis revealed the presence of triacetin; 3,6-dimethyl-3-octanol; 2R - Acetoxymethyl-1,3,3-trimethtyl - 4t - (3-methyl-2-buten-1-yl) - 1c - cyclohexanol and Stigmastan - 3,5-diene in DCM fraction. These compounds were docked with the active sites of cyclooxygenase-2 (COX-2). Triacetin, 3,6-dimethyl-3-Octanol, and 2R-Acetoxymethyl-1,3,3-trimethtyl-4t-(3-methyl-2-buten-1-yl)-1c-cyclohexanol docked comfortably with COX-2 with good scoring function (-CDocker energy) indicating their inhibitory potency against COX-2. 3,6-dimethyl-3-Octanol, displayed the lowest predicted free energy of binding (-21.4kcalmol(-1)) suggesting its stronger interaction with COX-2, this was followed by 2R - Acetoxymethyl-1, 3, 3-trimethtyl-4t-(3-methyl-2-buten-1-yl)-1c-cyclhexanol (BE=-20.5kcalmol(-1)), and triacetin (BE=-10.9kcalmol(-1)). Stigmastan - 3,5-diene failed to dock with COX-2. The observed suppressive effect of the DCM fraction of C. volubile flower methanolic extract on phagocytic oxidative burst indicates an immunomodulatory potential. This is further reflected in its free scavenging activities and synergetic modulation of COX-2 activities by its identified compounds in silico.

  1. Number of transients/Q-bursts in ELF-band as possible criterion for global thunderstorm activity estimation.

    NASA Astrophysics Data System (ADS)

    Ondraskova, Adriena; Sevcik, Sebastian

    2015-04-01

    Schumann resonances (SR) are resonant electromagnetic oscillations in extremely low frequency band (ELF, 3 Hz - 3 kHz), which arise in the Earth-ionosphere cavity due to lightning activity in planetary range. The time records in the ELF-band consist of background signals and ELF transients/Q-bursts superimposed on the background exceeding it by a factor of 5 - 10. The former are produced by the common worldwide thunderstorm activity (100 - 150 events per second), the latter origin from individual intense distant lightning discharges (100 - 120 powerful strokes per hour). A Q-burst is produced by a combination of direct and antipodal pulses and the decisive factor for its shape follows from the source-to-observer distance (SOD). Diurnal/seasonal variations of global thunderstorm activity can be deduced from spectral amplitudes of SR modes. Here we focus on diurnal/seasonal variations of the number of ELF-transients assuming that it is another way of lightning activity estimation. To search for transients, our own code was applied to the SR vertical electric component measured in October 2004 - December 2008 at the Astronomical and Geophysical Observatory of FMPI CU, Slovakia. Limits (min-max) for the width of primary spike, time difference between primary and secondary spike and the amplitude of the spike were chosen as criteria for the identification of the burst. Cumulative spectral amplitude of the first three SR modes compared with number of ELF-transients in monthly averaged diurnal variations quite successfully confirmed, that the number of transients can be a suitable criterion for the quantification of global lightning activity.

  2. Extracellular K+ in the supraoptic nucleus of the rat during reflex bursting activity by oxytocin neurones.

    PubMed Central

    Coles, J A; Poulain, D A

    1991-01-01

    1. We have investigated changes in extracellular potassium concentration [K+]o in the supraoptic nucleus of lactating rats and in particular those that occur during the intense burst of firing by the oxytocin neurones involved in the milk ejection reflex. 2. Double-barrelled K(+)-selective microelectrodes containing a highly selective sensor based on valinomycin were lowered through the exposed cortex towards the supraoptic nucleus (SON) of female rats anaesthetized with urethane. The mean resting [K+]o in the hypothalami of five rats was 2.4 mM, S.D. = 0.3 mM. 3. Where the reference barrel recorded extracellular action potentials from an oxytocin cell, the reflex burst of firing (4 s, typical maximum 50 Hz) was accompanied by a mean increase in [K+]o (delta[K+]o) of 0.22 mM (S.E.M. = 0.02 mM, fifty-seven bursts in eight cells in seven rats). The rise in [K+]o did not begin more than 0.1 s before the onset of the burst, and began to fall from its maximum during the burst. Slow field potentials, indicative of spatial buffering of K+, were undetectable (less than 50 microV). When the electrode was advanced in steps, the amplitudes of both delta[K+]o and the action potential declined steeply to about 10% over a distance of 20 microns: K+ from oxytocin cells appears to be prevented from dispersing freely through the extracellular space of the SON. 4. When the electrode recorded action potentials from a vasopressin cell, delta[K+]o during an oxytocin cell burst was very small: 0.021 mM (S.E.M. = 0.005 mM). At other sites in the SON, where antidromic stimulation evoked a field potential but no action potential, delta[K+]o was 0.047 +/- 0.005 mM. We conclude that the reason oxytocin bursts do not affect vasopressin cells is that [K+]o rises very little around vasopressin cells. A fortiori, since the increases in [K+]o were very small except where action potentials from oxytocin cells were recorded, they can make no significant contribution to synchronizing the onsets of

  3. Mechanisms Underlying Adaptation of Respiratory Network Activity to Modulatory Stimuli in the Mouse Embryo

    PubMed Central

    Chevalier, Marc; De Sa, Rafaël; Cardoit, Laura; Thoby-Brisson, Muriel

    2016-01-01

    Breathing is a rhythmic behavior that requires organized contractions of respiratory effector muscles. This behavior must adapt to constantly changing conditions in order to ensure homeostasis, proper body oxygenation, and CO2/pH regulation. Respiratory rhythmogenesis is controlled by neural networks located in the brainstem. One area considered to be essential for generating the inspiratory phase of the respiratory rhythm is the preBötzinger complex (preBötC). Rhythmogenesis emerges from this network through the interplay between the activation of intrinsic cellular properties (pacemaker properties) and intercellular synaptic connections. Respiratory activity continuously changes under the impact of numerous modulatory substances depending on organismal needs and environmental conditions. The preBötC network has been shown to become active during the last third of gestation. But only little is known regarding the modulation of inspiratory rhythmicity at embryonic stages and even less on a possible role of pacemaker neurons in this functional flexibility during the prenatal period. By combining electrophysiology and calcium imaging performed on embryonic brainstem slice preparations, we provide evidence showing that embryonic inspiratory pacemaker neurons are already intrinsically sensitive to neuromodulation and external conditions (i.e., temperature) affecting respiratory network activity, suggesting a potential role of pacemaker neurons in mediating rhythm adaptation to modulatory stimuli in the embryo. PMID:27239348

  4. Unusual Central Engine Activity in the Double Burst GRB 110709B

    NASA Technical Reports Server (NTRS)

    Zhang, Bin-Bin; Burrows, David N.; Zhang, Bing; Meszaros, Peter; Stratta, Giulia; D'Elia, Valerio; Frederiks, Dmitry; Golenetskii, S.; Cummings, Jay R.; Wang, Xiang-Yu; Falcone, Abraham D.; Barthelmy, Scott D.; Gehrels, Neil

    2011-01-01

    The double burst, GRB 110709B, triggered Swift/BAT twice at 21:32:39 UT and 21:43:45 UT, respectively, on 9 July 2011. This is the first time we observed a GRB with two BAT triggers. In this paper, we present simultaneous Swift and Konus-WIND observations of this unusual GRB and its afterglow. If the two events are from the same physical origin, their different time-dependent spectral evolution suggest they must belong to different episodes of the central engine, which may be a magnetar-to-BH accretion system.

  5. Respiratory pattern in awake rats: effects of motor activity and of alerting stimuli.

    PubMed

    Kabir, Muammar M; Beig, Mirza I; Baumert, Mathias; Trombini, Mimosa; Mastorci, Francesca; Sgoifo, Andrea; Walker, Frederick R; Day, Trevor A; Nalivaiko, Eugene

    2010-08-04

    Our aim was to assess the impact of motor activity and of arousing stimuli on respiratory rate in the awake rats. The study was performed in male adult Sprague-Dawley (SD, n=5) and Hooded Wistar (HW, n=5) rats instrumented for ECG telemetry. Respiratory rate was recorded using whole-body plethysmograph, with a piezoelectric sensor attached for the simultaneous assessment of motor activity. All motor activity was found to be associated with an immediate increase in respiratory rate that remained elevated for the whole duration of movement; this was reflected by: i) bimodal distribution of respiratory intervals (modes for slow peak: 336+/-19 and 532+/-80 ms for HW and SD, p<0.05; modes for fast peak 128+/-6 and 132+/-7 ms for HW and SD, NS); and ii) a tight correlation between total movement time and total time of tachypnoea, with an R(2) ranging 0.96-0.99 (n=10, p<0001). The extent of motor-related tachypnoea was significantly correlated with the intensity of associated movement. Mild alerting stimuli produced stereotyped tachypnoeic responses, without affecting heart rate: tapping the chamber raised respiratory rate from 117+/-7 to 430+/-15 cpm; sudden side move--from 134+/-13 to 487+/-16 cpm, and turning on lights--from 136+/-12 to 507+/-14 cpm (n=10; p<0.01 for all; no inter-strain differences). We conclude that: i) sniffing is an integral part of the generalized arousal response and does not depend on the modality of sensory stimuli; ii) tachypnoea is a sensitive index of arousal; and iii) respiratory rate is tightly correlated with motor activity.

  6. Burst-firing activity of presumed 5-HT neurones of the rat dorsal raphe nucleus: electrophysiological analysis by antidromic stimulation.

    PubMed

    Hajós, M; Sharp, T

    1996-11-18

    We recently reported raphe neurones which frequently fired spikes in short bursts. However, the action potentials were broad and the neurones fired in a slow and regular pattern, suggesting they were an unusual type of 5-hydroxytryptamine (5-HT) neurone. In the present study, we investigated whether these putative burst-firing 5-HT neurones project to the forebrain and whether all spikes fired in bursts propagate along the axon. In anaesthetised rats, electrical stimulation of the medial forebrain bundle evoked antidromic spikes in both burst-firing neurones and in single-spiking, classical 5-HT neurones recorded in the dorsal raphe nucleus. Although the antidromic spike latency of the single-spiking and burst-firing neurones showed a clear overlap, burst-firing neurones had a significantly shorter latency than single-spiking neurones. For both burst-firing neurones and classical 5-HT neurones, antidromic spikes made collisions with spontaneously occurring spikes. Furthermore, in all burst-firing neurones tested, first, second and third order spikes in a burst could be made to collide with antidromic spike. Interestingly, in a small number of burst-firing neurones, antidromic stimulation evoked spike doublets, similar to those recorded spontaneously. From these data we conclude that burst-firing neurones in the dorsal raphe nucleus project to the forebrain, and each spike generated by the burst propagates along the axon and could thereby release transmitter (5-HT).

  7. Respiratory control determines respiration and nitrogenase activity of Rhizobium leguminosarum bacteroids.

    PubMed

    Haaker, H; Szafran, M; Wassink, H; Klerk, H; Appels, M

    1996-08-01

    The relationship between the O2 input rate into a suspension of Rhizobium leguminosarum bacteroids, the cellular ATP and ADP pools, and the whole-cell nitrogenase activity during L-malate oxidation has been studied. It was observed that inhibition of nitrogenase by excess O2 coincided with an increase of the cellular ATP/ADP ratio. When under this condition the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) was added, the cellular ATP/ADP ratio was lowered while nitrogenase regained activity. To explain these observations, the effects of nitrogenase activity and CCCP on the O2 consumption rate of R. leguminosarum bacteroids were determined. From 100 to 5 microM O2, a decline in the O2 consumption rate was observed to 50 to 70% of the maximal O2 consumption rate. A determination of the redox state of the cytochromes during an O2 consumption experiment indicated that at O2 concentrations above 5 microM, electron transport to the cytochromes was rate-limiting oxidation and not the reaction of reduced cytochromes with oxygen. The kinetic properties of the respiratory chain were determined from the deoxygenation of oxyglobins. In intact cells the maximal deoxygenation activity was stimulated by nitrogenase activity or CCCP. In isolated cytoplasmic membranes NADH oxidation was inhibited by respiratory control. The dehydrogenase activities of the respiratory chain were rate-limiting oxidation at O2 concentrations (if >300 nM. Below 300 nM the terminal oxidase system followed Michaelis-Menten kinetics (Km of 45 +/- 8 nM). We conclude that (i) respiration in R. leguminosarum bacteroids takes place via a respiratory chain terminating at a high-affinity oxidase system, (ii) the activity of the respiratory chain is inhibited by the proton motive force, and (iii) ATP hydrolysis by nitrogenase can partly relieve the inhibition of respiration by the proton motive force and thus stimulate respiration at nanomolar concentrations of O2.

  8. Na+/K+ pump interacts with the h-current to control bursting activity in central pattern generator neurons of leeches

    PubMed Central

    Kueh, Daniel; Barnett, William H; Cymbalyuk, Gennady S; Calabrese, Ronald L

    2016-01-01

    The dynamics of different ionic currents shape the bursting activity of neurons and networks that control motor output. Despite being ubiquitous in all animal cells, the contribution of the Na+/K+ pump current to such bursting activity has not been well studied. We used monensin, a Na+/H+ antiporter, to examine the role of the pump on the bursting activity of oscillator heart interneurons in leeches. When we stimulated the pump with monensin, the period of these neurons decreased significantly, an effect that was prevented or reversed when the h-current was blocked by Cs+. The decreased period could also occur if the pump was inhibited with strophanthidin or K+-free saline. Our monensin results were reproduced in model, which explains the pump’s contributions to bursting activity based on Na+ dynamics. Our results indicate that a dynamically oscillating pump current that interacts with the h-current can regulate the bursting activity of neurons and networks. DOI: http://dx.doi.org/10.7554/eLife.19322.001 PMID:27588351

  9. The interaction of intrinsic dynamics and network topology in determining network burst synchrony.

    PubMed

    Gaiteri, Chris; Rubin, Jonathan E

    2011-01-01

    The pre-Bötzinger complex (pre-BötC), within the mammalian respiratory brainstem, represents an ideal system for investigating the synchronization properties of complex neuronal circuits via the interaction of cell-type heterogeneity and network connectivity. In isolation, individual respiratory neurons from the pre-BötC may be tonically active, rhythmically bursting, or quiescent. Despite this intrinsic heterogeneity, coupled networks of pre-BötC neurons en bloc engage in synchronized bursting that can drive inspiratory motor neuron activation. The region's connection topology has been recently characterized and features dense clusters of cells with occasional connections between clusters. We investigate how the dynamics of individual neurons (quiescent/bursting/tonic) and the betweenness centrality of neurons' positions within the network connectivity graph interact to govern network burst synchrony, by simulating heterogeneous networks of computational model pre-BötC neurons. Furthermore, we compare the prevalence and synchrony of bursting across networks constructed with a variety of connection topologies, analyzing the same collection of heterogeneous neurons in small-world, scale-free, random, and regularly structured networks. We find that several measures of network burst synchronization are determined by interactions of network topology with the intrinsic dynamics of neurons at central network positions and by the strengths of synaptic connections between neurons. Surprisingly, despite the functional role of synchronized bursting within the pre-BötC, we find that synchronized network bursting is generally weakest when we use its specific connection topology, which leads to synchrony within clusters but poor coordination across clusters. Overall, our results highlight the relevance of interactions between topology and intrinsic dynamics in shaping the activity of networks and the concerted effects of connectivity patterns and dynamic heterogeneities.

  10. Respiratory Membrane endo-Hydrogenase Activity in the Microaerophile Azorhizobium caulinodans Is Bidirectional

    PubMed Central

    Sprecher, Brittany N.; Gittings, Margo E.; Ludwig, Robert A.

    2012-01-01

    Background The microaerophilic bacterium Azorhizobium caulinodans, when fixing N2 both in pure cultures held at 20 µM dissolved O2 tension and as endosymbiont of Sesbania rostrata legume nodules, employs a novel, respiratory-membrane endo-hydrogenase to oxidize and recycle endogenous H2 produced by soluble Mo-dinitrogenase activity at the expense of O2. Methods and Findings From a bioinformatic analysis, this endo-hydrogenase is a core (6 subunit) version of (14 subunit) NADH:ubiquinone oxidoreductase (respiratory complex I). In pure A. caulinodans liquid cultures, when O2 levels are lowered to <1 µM dissolved O2 tension (true microaerobic physiology), in vivo endo-hydrogenase activity reverses and continuously evolves H2 at high rates. In essence, H+ ions then supplement scarce O2 as respiratory-membrane electron acceptor. Paradoxically, from thermodynamic considerations, such hydrogenic respiratory-membrane electron transfer need largely uncouple oxidative phosphorylation, required for growth of non-phototrophic aerobic bacteria, A. caulinodans included. Conclusions A. caulinodans in vivo endo-hydrogenase catalytic activity is bidirectional. To our knowledge, this study is the first demonstration of hydrogenic respiratory-membrane electron transfer among aerobic (non-fermentative) bacteria. When compared with O2 tolerant hydrogenases in other organisms, A. caulinodans in vivo endo-hydrogenase mediated H2 production rates (50,000 pmol 109·cells−1 min−1) are at least one-thousandfold higher. Conceivably, A. caulinodans respiratory-membrane hydrogenesis might initiate H2 crossfeeding among spatially organized bacterial populations whose individual cells adopt distinct metabolic states in response to variant O2 availability. Such organized, physiologically heterogeneous cell populations might benefit from augmented energy transduction and growth rates of the populations, considered as a whole. PMID:22662125

  11. Learning-induced reduction in post-burst after-hyperpolarization (AHP) is mediated by activation of PKC.

    PubMed

    Seroussi, Yaron; Brosh, Inbar; Barkai, Edi

    2002-09-01

    We studied the role of protein kinase C (PKC) and protein kinase A (PKA) in mediating learning-related long lasting reduction of the post-burst after-hyperpolarization (AHP) in cortical pyramidal neurons. We have shown previously that pyramidal neurons in the rat piriform (olfactory) cortex from trained (TR) rats have reduced post-burst AHP for 3 days after odour-discrimination learning, and that this reduction is due to decreased conductance of calcium-dependent potassium current. In the present study, we examined whether this long-lasting reduction in AHP is mediated by second messenger systems. The broad-spectrum kinase inhibitor, H7, increased the AHP in neurons from TR rats, but not in neurons from pseudo-trained (pseudo-TR) and naive rats. Consequently, the difference in AHP amplitude between neurons from TR and control animals was diminished. This effect was also obtained by application of the specific PKC inhibitor, GF-109203x. The PKC activator, 1-Oleoyl-2-acetyl-sn-glycerol (OAG), significantly reduced the AHP in neurons from naive and pseudo-TR rats, but not in neurons from TR rats, so that the difference between the groups was abolished. The PKA-specific inhibitor, H-89, increased the AHP in neurons from all groups to a similar extent, and the difference in AHP amplitude between neurons from TR rats and neurons from controls was maintained. We suggest that while the post-burst AHP in piriform cortex pyramidal neurons is modulated by both PKC and PKA, a PKC-dependent process maintains the learning-related reduction of the AHP in these cells.

  12. When it is too hot for photosynthesis: heat-induced instability of photosynthesis in relation to respiratory burst, cell permeability changes and H₂O₂ formation.

    PubMed

    Hüve, Katja; Bichele, Irina; Rasulov, Bahtijor; Niinemets, Ulo

    2011-01-01

    Photosynthesis rate (A(n)) becomes unstable above a threshold temperature, and the recovery upon return to low temperature varies because of reasons not fully understood. We investigated responses of A(n), dark respiration and chlorophyll fluorescence to supraoptimal temperatures of varying duration and kinetics in Phaseolus vulgaris asking whether the instability of photosynthesis under severe heat stress is associated with cellular damage. Cellular damage was assessed by Evans blue penetration (enhanced membrane permeability) and by H₂O₂ generation [3,3'-diaminobenzidine 4HCl (DAB)-staining]. Critical temperature for dark fluorescence (F(0) ) rise (T(F)) was at 46-48 °C, and a burst of respiration was observed near T(F). However, A(n) was strongly inhibited already before T(F) was reached. Membrane permeability increased with temperature according to a switch-type response, with enhanced permeability observed above 48 °C. Experiments with varying heat pulse lengths and intensities underscored the threshold-type loss of photosynthetic function, and indicated that the degree of photosynthetic deterioration and cellular damage depended on accumulated heat-dose. Beyond the 'point of no return', propagation of cellular damage and reduction of photosynthesis continued upon transfer to lower temperatures and photosynthetic recovery was slow or absent. We conclude that instability of photosynthesis under severe heat stress is associated with time-dependent propagation of cellular lesions.

  13. Changes in respiratory activity induced by mastication during oral breathing in humans.

    PubMed

    Daimon, Shigeru; Yamaguchi, Kazunori

    2014-06-01

    We examined the effect of oral breathing on respiratory movements, including the number of respirations and the movement of the thoracic wall at rest and while chewing gum. Forty normal nose breathers were selected by detecting expiratory airflow from the mouth using a CO2 sensor. Chest measurements were recorded using a Piezo respiratory belt transducer, and electromyographic (EMG) activity of the masseter and trapezius muscles were recorded at rest and while chewing gum during nasal or oral breathing. Oral breathing was introduced by completely occluding the nostrils with a nose clip. During oral breathing, the respiration rate was significantly lower while chewing gum than while at rest (P < 0.05). While chewing gum, the respiration rate was significantly lower during oral breathing than during nasal breathing (P < 0.05). During oral breathing, thoracic movement was significantly higher while chewing gum than while at rest (P < 0.05). Thoracic movement was significantly greater during oral breathing than during nasal breathing (P < 0.05). The trapezius muscle exhibited significant EMG activity when chewing gum during oral breathing. The activity of the trapezius muscle coincided with increased movement of the thoracic wall. Chewing food while breathing through the mouth interferes with and decreases the respiratory cycle and promotes unusual respiratory movement of the thoracic wall, which is directed by the activity of accessory muscles of respiration.

  14. Pyrazinoic acid decreases the proton motive force, respiratory ATP synthesis activity, and cellular ATP levels.

    PubMed

    Lu, Ping; Haagsma, Anna C; Pham, Hoang; Maaskant, Janneke J; Mol, Selena; Lill, Holger; Bald, Dirk

    2011-11-01

    Pyrazinoic acid, the active form of the first-line antituberculosis drug pyrazinamide, decreased the proton motive force and respiratory ATP synthesis rates in subcellular mycobacterial membrane assays. Pyrazinoic acid also significantly lowered cellular ATP levels in Mycobacterium bovis BCG. These results indicate that the predominant mechanism of killing by this drug may operate by depletion of cellular ATP reserves.

  15. A longitudinal study of poor performance and subclinical respiratory viral activity in Standardbred trotters

    PubMed Central

    Back, Helena; Penell, Johanna; Pringle, John; Isaksson, Mats; Ronéus, Nils; Treiberg Berndtsson, Louise; Ståhl, Karl

    2015-01-01

    Introduction While clinical respiratory disease is considered a main cause of poor performance in horses, the role of subclinical respiratory virus infections is less clear and needs further investigation. Aims and objectives In this descriptive longitudinal study the relationship of markers of subclinical respiratory viral activity to occurrence of poor performance in racing Standardbred trotters was investigated. Material and methods 66 elite Standardbred trotters were followed for 13 months by nasal swabs analysed with qPCR for equine influenza virus, equine arteritis virus, equine rhinitis B virus (ERBV), equine herpesvirus type 1(EHV-1) and equine herpesvirus type 4 (EHV-4) and serology to equine rhinitis A virus (ERAV), ERBV, EHV-1 and EHV-4, as well as the acute phase protein serum amyloid A (SAA). Findings on lab analyses were subsequently assessed for possible correlations to workload performance and trainer opinion measures of poor performance. Results Despite occurrence of poor performance and subclinical viral activity the authors were unable to detect association neither between subclinical viral activity and poor performance, nor between SAA elevations and either viral activity or poor performance. Conclusions Consistent with earlier study results, antibody titres to ERBV remained high for at least a year and few horses two years or older were seronegative to either ERAV or ERBV. In absence of clinical signs, serology to common respiratory viruses appears to have little diagnostic benefit in evaluation of poor performance in young athletic horses. PMID:26392904

  16. Medullary respiratory neural activity during hypoxia in NREM and REM sleep in the cat.

    PubMed

    Lovering, Andrew T; Fraigne, Jimmy J; Dunin-Barkowski, Witali L; Vidruk, Edward H; Orem, John M

    2006-02-01

    Intact unanesthetized cats hyperventilate in response to hypocapnic hypoxia in both wakefulness and sleep. This hyperventilation is caused by increases in diaphragmatic activity during inspiration and expiration. In this study, we recorded 120 medullary respiratory neurons during sleep in hypoxia. Our goal was to understand how these neurons change their activity to increase breathing efforts and frequency in response to hypoxia. We found that the response of medullary respiratory neurons to hypoxia was variable. While the activity of a small majority of inspiratory (58%) and expiratory (56%) neurons was increased in response to hypoxia, the activity of a small majority of preinspiratory (57%) neurons was decreased. Cells that were more active in hypoxia had discharge rates that averaged 183% (inspiratory decrementing), 154% (inspiratory augmenting), 155% (inspiratory), 230% (expiratory decrementing), 191% (expiratory augmenting), and 136% (expiratory) of the rates in normoxia. The response to hypoxia was similar in non-rapid-eye-movement (NREM) and REM sleep. Additionally, changes in the profile of activity were observed in all cell types examined. These changes included advanced, prolonged, and abbreviated patterns of activity in response to hypoxia; for example, some inspiratory neurons prolonged their discharge into expiration during the postinspiratory period in hypoxia but not in normoxia. Although changes in activity of the inspiratory neurons could account for the increased breathing efforts and activity of the diaphragm observed during hypoxia, the mechanisms responsible for the change in respiratory rate were not revealed by our data.

  17. The β Subunit Increases the Ca2+ Sensitivity of Large Conductance Ca2+-activated Potassium Channels by Retaining the Gating in the Bursting States

    PubMed Central

    Nimigean, Crina M.; Magleby, Karl L.

    1999-01-01

    Coexpression of the β subunit (KV,Caβ) with the α subunit of mammalian large conductance Ca2+- activated K+ (BK) channels greatly increases the apparent Ca2+ sensitivity of the channel. Using single-channel analysis to investigate the mechanism for this increase, we found that the β subunit increased open probability (Po) by increasing burst duration 20–100-fold, while having little effect on the durations of the gaps (closed intervals) between bursts or on the numbers of detected open and closed states entered during gating. The effect of the β subunit was not equivalent to raising intracellular Ca2+ in the absence of the beta subunit, suggesting that the β subunit does not act by increasing all the Ca2+ binding rates proportionally. The β subunit also inhibited transitions to subconductance levels. It is the retention of the BK channel in the bursting states by the β subunit that increases the apparent Ca2+ sensitivity of the channel. In the presence of the β subunit, each burst of openings is greatly amplified in duration through increases in both the numbers of openings per burst and in the mean open times. Native BK channels from cultured rat skeletal muscle were found to have bursting kinetics similar to channels expressed from alpha subunits alone. PMID:10051518

  18. Amyloidosis involving the respiratory system: 5-year's experience of a multi-disciplinary group's activity.

    PubMed

    Scala, Raffaele; Maccari, Uberto; Madioni, Chiara; Venezia, Duccio; La Magra, Lidia Calogera

    2015-01-01

    Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice.

  19. Burst activity of the Crab Nebula and its pulsar at high and ultra-high energies

    NASA Astrophysics Data System (ADS)

    Lidvansky, A. S.

    2016-06-01

    Characteristics of the flares of gamma rays detected from the Crab Nebula by the AGILE and Fermi-LAT satellite instruments are compared with those of a gamma ray burst recorded by several air shower arrays on February 23, 1989 and with one recent observation made by ARGO-YBJ array. It is demonstrated that though pulsar-periodicity and energy spectra of emissions at 100 MeV (satellite gamma ray telescopes) and 100 TeV (EAS arrays) are different, their time structures seem to be similar. Moreover, may be the difference between "flares" and "waves" recently found in the Crab Nebula emission by AGILE team also exists at ultra-high energies.

  20. Change and Stability in Active and Passive Social Influence Dynamics during Natural Drinking Events: A Longitudinal Measurement-Burst Study.

    PubMed

    Cullum, Jerry; O'Grady, Megan; Armeli, Stephen; Tennen, Howard

    2012-01-01

    We examined the link between social norms and active social influences occurring during natural social drinking contexts. Across 4 yearly measurement-bursts, college students (N = 523) reported daily for 30-day periods on drinking norms, drinking offers, how many drinks they accepted, and personal drinking levels during social drinking events. In contexts where drinking norms were higher, students were more likely to both receive and comply with drinking offers. These acute social influences were highly stable throughout college, but affected men and women differently across time: Women received more drinking offers than men, especially at the beginning of college and when norms were higher, but men complied with more drinking offers per occasion. These effects were not attributable to between-person differences in social drinking motives or drinking levels, nor to within-person patterns of situation-selection. The present work suggests that context-specific drinking norms catalyze active social influence attempts, and further promote compliance drinking.

  1. High atmospheric carbon dioxide-dependent alleviation of salt stress is linked to RESPIRATORY BURST OXIDASE 1 (RBOH1)-dependent H2O2 production in tomato (Solanum lycopersicum)

    PubMed Central

    Yi, Changyu; Yao, Kaiqian; Cai, Shuyu; Li, Huizi; Zhou, Jie; Xia, Xiaojian; Shi, Kai; Yu, Jingquan; Foyer, Christine Helen; Zhou, Yanhong

    2015-01-01

    Plants acclimate rapidly to stressful environmental conditions. Increasing atmospheric CO2 levels are predicted to influence tolerance to stresses such as soil salinity but the mechanisms are poorly understood. To resolve this issue, tomato (Solanum lycopersicum) plants were grown under ambient (380 μmol mol–1) or high (760 μmol mol–1) CO2 in the absence or presence of sodium chloride (100mM). The higher atmospheric CO2 level induced the expression of RESPIRATORY BURST OXIDASE 1 (SlRBOH1) and enhanced H2O2 accumulation in the vascular cells of roots, stems, leaf petioles, and the leaf apoplast. Plants grown with higher CO2 levels showed improved salt tolerance, together with decreased leaf transpiration rates and lower sodium concentrations in the xylem sap, vascular tissues, and leaves. Silencing SlRBOH1 abolished high CO2 -induced salt tolerance and increased leaf transpiration rates, as well as enhancing Na+ accumulation in the plants. The higher atmospheric CO2 level increased the abundance of a subset of transcripts involved in Na+ homeostasis in the controls but not in the SlRBOH1-silenced plants. It is concluded that high atmospheric CO2 concentrations increase salt stress tolerance in an apoplastic H2O2 dependent manner, by suppressing transpiration and hence Na+ delivery from the roots to the shoots, leading to decreased leaf Na+ accumulation. PMID:26417022

  2. High atmospheric carbon dioxide-dependent alleviation of salt stress is linked to RESPIRATORY BURST OXIDASE 1 (RBOH1)-dependent H2O2 production in tomato (Solanum lycopersicum).

    PubMed

    Yi, Changyu; Yao, Kaiqian; Cai, Shuyu; Li, Huizi; Zhou, Jie; Xia, Xiaojian; Shi, Kai; Yu, Jingquan; Foyer, Christine Helen; Zhou, Yanhong

    2015-12-01

    Plants acclimate rapidly to stressful environmental conditions. Increasing atmospheric CO2 levels are predicted to influence tolerance to stresses such as soil salinity but the mechanisms are poorly understood. To resolve this issue, tomato (Solanum lycopersicum) plants were grown under ambient (380 μmol mol(-1)) or high (760 μmol mol(-1)) CO2 in the absence or presence of sodium chloride (100mM). The higher atmospheric CO2 level induced the expression of RESPIRATORY BURST OXIDASE 1 (SlRBOH1) and enhanced H2O2 accumulation in the vascular cells of roots, stems, leaf petioles, and the leaf apoplast. Plants grown with higher CO2 levels showed improved salt tolerance, together with decreased leaf transpiration rates and lower sodium concentrations in the xylem sap, vascular tissues, and leaves. Silencing SlRBOH1 abolished high CO2 -induced salt tolerance and increased leaf transpiration rates, as well as enhancing Na(+) accumulation in the plants. The higher atmospheric CO2 level increased the abundance of a subset of transcripts involved in Na(+) homeostasis in the controls but not in the SlRBOH1-silenced plants. It is concluded that high atmospheric CO2 concentrations increase salt stress tolerance in an apoplastic H2O2 dependent manner, by suppressing transpiration and hence Na(+) delivery from the roots to the shoots, leading to decreased leaf Na(+) accumulation.

  3. [Activity of an ampicillin/sulbactam combination in respiratory infections].

    PubMed

    Mangiarotti, P; Manara, G; Grassi, G; Gialdroni Grassi, G

    1989-01-01

    The combination of sulbactam (S) plus ampicillin (A) extends the activity of ampicillin (Amp) against beta-lactamase producing strains. This combination is therefore useful in many clinical situations including LRTI. A clinical trial was carried out to evaluate the clinical and bacteriological efficacy of S-Amp in LRTI in comparison with Amp alone. Concerning clinical outcome the results were satisfactory in 83.3% of cases for S-Amp group and 82.3% of cases for Amp group. Pathogen eradication was achieved in 87.5% and 70.5% of cases respectively for the S-Amp and Amp group.

  4. Smart helmet: Monitoring brain, cardiac and respiratory activity.

    PubMed

    von Rosenberg, Wilhelm; Chanwimalueang, Theerasak; Goverdovsky, Valentin; Mandic, Danilo P

    2015-01-01

    The timing of the assessment of the injuries following a road-traffic accident involving motorcyclists is absolutely crucial, particularly in the events with head trauma. Standard apparatus for monitoring cardiac activity is usually attached to the limbs or the torso, while the brain function is routinely measured with a separate unit connected to the head-mounted sensors. In stark contrast to these, we propose an integrated system which incorporates the two functionalities inside an ordinary motorcycle helmet. Multiple fabric electrodes were mounted inside the helmet at positions featuring good contact with the skin at different sections of the head. The experimental results demonstrate that the R-peaks (and therefore the heart rate) can be reliably extracted from potentials measured with electrodes on the mastoids and the lower jaw, while the electrodes on the forehead enable the observation of neural signals. We conclude that various vital sings and brain activity can be readily recorded from the inside of a helmet in a comfortable and inconspicuous way, requiring only a negligible setup effort.

  5. HCN channels contribute to serotonergic modulation of ventral surface chemosensitive neurons and respiratory activity

    PubMed Central

    Hawkins, Virginia E.; Hawryluk, Joanna M.; Takakura, Ana C.; Tzingounis, Anastasios V.; Moreira, Thiago S.

    2014-01-01

    Chemosensitive neurons in the retrotrapezoid nucleus (RTN) provide a CO2/H+-dependent drive to breathe and function as an integration center for the respiratory network, including serotonergic raphe neurons. We recently showed that serotonergic modulation of RTN chemoreceptors involved inhibition of KCNQ channels and activation of an unknown inward current. Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels are the molecular correlate of the hyperpolarization-activated inward current (Ih) and have a high propensity for modulation by serotonin. To investigate whether HCN channels contribute to basal activity and serotonergic modulation of RTN chemoreceptors, we characterize resting activity and the effects of serotonin on RTN chemoreceptors in vitro and on respiratory activity of anesthetized rats in the presence or absence of blockers of KCNQ (XE991) and/or HCN (ZD7288, Cs+) channels. We found in vivo that bilateral RTN injections of ZD7288 increased respiratory activity and in vitro HCN channel blockade increased activity of RTN chemoreceptors under control conditions, but this was blunted by KCNQ channel inhibition. Furthermore, in vivo unilateral RTN injection of XE991 plus ZD7288 eliminated the serotonin response, and in vitro serotonin sensitivity was eliminated by application of XE991 and ZD7288 or SQ22536 (adenylate cyclase blocker). Serotonin-mediated activation of RTN chemoreceptors was blocked by a 5-HT7-receptor blocker and mimicked by a 5-HT7-receptor agonist. In addition, serotonin caused a depolarizing shift in the voltage-dependent activation of Ih. These results suggest that HCN channels contribute to resting chemoreceptor activity and that serotonin activates RTN chemoreceptors and breathing in part by a 5-HT7 receptor-dependent mechanism and downstream activation of Ih. PMID:25429115

  6. Real-time detection of respiratory activity using an inertial measurement unit.

    PubMed

    Gollee, Henrik; Chen, Wei

    2007-01-01

    In this paper the use of an inertial measurement unit (IMU) to measure respiratory activity is presented. Movement of the abdomen was recorded by an IMU attached to a belt around the abdomen. The resulting signal was compared with reference measurements of the airflow at the mouth. The results of experimental evaluation show that the method can correctly detect the number of breaths together with the timing of the onsets of expiration and inspiration in real-time. They also indicate that the signal can be used to differentiate between different breathing situations. This novel method could therefore be suitable for use in automatic abdominal stimulation systems to support respiratory activity in tetraplegia where the stimulation is applied depending on the respirator activity of the subject.

  7. [Role of the medial region of the hypothalamus in regulating the activity of the respiratory neurons of the medulla oblongata].

    PubMed

    Baklavadzhian, O G; Nersesian, L B

    1976-10-01

    The influence of high frequency stimulation of postero- and anteromedial hypothalamic regions on the activity of single neurons of the bulbar respiratory center was studied in anesthetized cats with normal respiration. No strictly localized facilitatory or inhibitory points were found in these regions. Excitatory as well as inhibitory descending pathways were activated by the hypothalamic stimulation. The effect was mainly facilitating. The excitatory and inhibitory influences of the medial hypothalamus modulated spike activity of both inspiratory and expiratory neurons of the bulbar respiratory center. Some functional aspects of the mechanism for hypothalamic regulation of the activity of bulbar respiratory neurons are discussed.

  8. Participation of a persistent sodium current and calcium-activated nonspecific cationic current to burst generation in trigeminal principal sensory neurons

    PubMed Central

    Tsuruyama, Kentaro; Hsiao, Chie-Fang

    2013-01-01

    The properties of neurons participating in masticatory rhythmogenesis are not clearly understood. Neurons within the dorsal trigeminal principal sensory nucleus (dPrV) are potential candidates as components of the masticatory central pattern generator (CPG). The present study examines in detail the ionic mechanisms controlling burst generation in dPrV neurons in rat (postnatal day 8–12) brain stem slices using whole cell and perforated patch-clamp methods. Nominal extracellular Ca2+ concentration transformed tonic discharge in response to a maintained step pulse of current into rhythmical bursting in 38% of nonbursting neurons. This change in discharge mode was suppressed by riluzole, a persistent Na+ current (INaP) antagonist. Veratridine, which suppresses the Na+ channel inactivation mechanism, induced rhythmical bursting in nonbursting neurons in normal artificial cerebrospinal fluid, suggesting that INaP contributes to burst generation. Nominal extracellular Ca2+ exposed a prominent afterdepolarizing potential (ADP) following a single spike induced by a 3-ms current pulse, which was suppressed, but not completely blocked, by riluzole. Application of BAPTA, a Ca2+ chelator, intracellularly, or flufenamic acid, a Ca2+-activated nonspecific cationic channel (ICAN) antagonist, extracellularly to the bath, suppressed rhythmical bursting and the postspike ADP. Application of drugs to alter Ca2+ release from endoplasmic reticulum also suppressed bursting. Finally, voltage-clamp methods demonstrated that nominal Ca2+ facilitated INaP and induced ICAN. These data demonstrate for the first time that the previously observed induction in dPrV neurons of rhythmical bursting in nominal Ca2+ is mediated by enhancement of INaP and onset of ICAN, which are dependent on intracellular Ca2+. PMID:23883859

  9. Non-invasive detection of respiratory muscles activity during assisted ventilation.

    PubMed

    Heyer, Laurent; Baconnier, Pierre F; Eberhard, André; Biot, Loïc; Viale, Jean-Paul; Perdrix, Jean-Pierre; Carry, Pierre-Yves

    2002-04-01

    The instantaneous pressure applied by the respiratory muscles [Pmus(t)] of a patient under ventilatory support may be continuously assessed with the help of a model of the passive respiratory system updated cycle by cycle. Inspiratory activity (IA) is considered present when Pmus goes below a given threshold. In six patients, we compared IA with (i) inspiratory activity (IAref) obtained from esophageal pressure and diaphragmatic EMG and (ii) that (IAvent) detected by the ventilator. In any case, a ventilator support onset coincides with an IA onset but the opposite is not true. IA onset is always later than IAref beginning ((0.21 +/- 0.10 s) and IA end always precedes IAref end (0.46 +/- 0.16 s). These results clearly deteriorate when the model is not updated.

  10. Administration of memantine and imipramine alters mitochondrial respiratory chain and creatine kinase activities in rat brain.

    PubMed

    Réus, Gislaine Z; Stringari, Roberto B; Rezin, Gislaine T; Fraga, Daiane B; Daufenbach, Juliana F; Scaini, Giselli; Benedet, Joana; Rochi, Natália; Streck, Emílio L; Quevedo, João

    2012-04-01

    Several studies have appointed for a role of glutamatergic system and/or mitochondrial function in major depression. In the present study, we evaluated the creatine kinase and mitochondrial respiratory chain activities after acute and chronic treatments with memantine (N-methyl-D: -aspartate receptor antagonist) and imipramine (tricyclic antidepressant) in rats. To this aim, rats were acutely or chronically treated for 14 days once a day with saline, memantine (5, 10 and 20 mg/kg) and imipramine (10, 20 and 30 mg/kg). After acute or chronic treatments, we evaluated mitochondrial respiratory chain complexes (I, II, II-III and IV) and creatine kinase activities in prefrontal cortex, hippocampus and striatum. Our results showed that both acute and chronic treatments with memantine or imipramine altered respiratory chain complexes and creatine kinase activities in rat brain; however, these alterations were different with relation to protocols (acute or chronic), complex, dose and brain area. Finally, these findings further support the hypothesis that the effects of imipramine and memantine could be involve mitochondrial function modulation.

  11. Longevity of U cells of differentiated yeast colonies grown on respiratory medium depends on active glycolysis.

    PubMed

    Čáp, Michal; Váchová, Libuše; Palková, Zdena

    2015-01-01

    Colonies of Saccharomyces cerevisiae laboratory strains pass through specific developmental phases when growing on solid respiratory medium. During entry into the so-called alkali phase, in which ammonia signaling is initiated, 2 prominent cell types are formed within the colonies: U cells in upper colony regions, which have a longevity phenotype and activate the expression of a large number of metabolic genes, and L cells in lower regions, which die more quickly and exhibit a starvation phenotype. Here, we performed a detailed analysis of the activities of enzymes of central carbon metabolism in lysates of both cell types and determined several fermentation end products, showing that previously reported expression differences are reflected in the different enzymatic capabilities of each cell type. Hence, U cells, despite being grown on respiratory medium, behave as fermenting cells, whereas L cells rely on respiratory metabolism and possess active gluconeogenesis. Using a spectrum of different inhibitors, we showed that glycolysis is essential for the formation, and particularly, the survival of U cells. We also showed that β-1,3-glucans that are released from the cell walls of L cells are the most likely source of carbohydrates for U cells.

  12. Relation Between Prefrontal Cortex Activity and Respiratory Rate During Mental Stress Tasks: A Near-Infrared Spectroscopic Study.

    PubMed

    Murayama, Yuta; Hu, Lizhen; Sakatani, Kaoru

    2016-01-01

    In order to clarify the central mechanism controlling respiratory rate during mental stress, we examined the relation between prefrontal cortex (PFC) activity and respiratory rate during mental arithmetic (MA) tasks. Employing two-channel near-infrared spectroscopy (NIRS), we measured hemoglobin (Hb) concentration changes in the bilateral PFC during MA tasks in normal adults. To evaluate asymmetry of the PFC activity, we calculated the laterality index (LI); (R-L)/(R + L) of oxy-Hb concentration changes (R = right, L = left); positive LI scores indicate right-dominant activity, while negative scores indicate left-dominant activity. For measurements of respiratory rate, we employed a Kinect motion sensor (Microsoft). The MA tasks increased both oxy-Hb in the bilateral PFC and respiratory rate (p < 0.001). In addition, there was a significant correlation between LI and respiratory rate (r = 0.582, p < 0.02). These results indicate that the MA-induced activity in the right PFC was greater than that in the left PFC in subjects with large increases of respiratory rate, suggesting that the right PFC has a greater role in cerebral regulation of respiratory rate during mental stress.

  13. The labile respiratory activity of ribcage muscles of the rat during sleep.

    PubMed

    Megirian, D; Pollard, M J; Sherrey, J H

    1987-08-01

    1. Sleep-waking states of chronically implanted rats were identified polygraphically while recording the integrated electromyogram (e.m.g.) of extrinsic (scalenus medius and levator costae) and intrinsic (external and internal interosseous intercostal and parasternal) muscles of the thoracic cage. Rats breathed air, air enriched in CO2 (5%) or air deficient in O2 (10% O2 in N2) and were free to adopt any desired posture. 2. In non-rapid eye movement (non-r.e.m.) sleep, the scalenus medius and intercostal muscles of the cephalic spaces were always inspiratory; intercostal muscles of the mid-thoracic spaces were commonly expiratory while the more caudal ones were only occasionally expiratory. Expiratory activity, when present in quiet wakefulness, extended for a variable period of time into non-r.e.m. sleep and always disappeared in r.e.m. sleep regardless of the ribcage muscle under study. 3. Inspiratory activity, when present in non-r.e.m. sleep, was unaffected, partially attenuated or abolished at entry into r.e.m. sleep. The peak integrated e.m.g. activity of ribcage muscles was measured as a function of posture, gas mixture breathed and ribcage site: (a) the greater the degree of curled-up posture, the greater the respiratory activity of scalenus medius, an effect augmented by CO2 but depressed by hypoxia, and (b) the more caudally placed ribcage muscles exhibited respiratory activity which was essentially unaffected by posture and gas mixture inspired. 4. The presence or absence of tonic activity in ribcage respiratory muscles during non-r.e.m. sleep was unrelated to posture. When tonic activity was present, it always disappeared in r.e.m. sleep. When expiratory activity was present in non-r.e.m. sleep, it too always disappeared in r.e.m. sleep. Inspiratory activity present in non-r.e.m. sleep was variably affected at entry into r.e.m. sleep; it was unchanged, partially attenuated or abolished. 5. It is concluded that thoracic cage muscles exhibit marked

  14. Respiratory Muscle Activity During Simultaneous Stationary Cycling and Inspiratory Muscle Training.

    PubMed

    Hellyer, Nathan J; Folsom, Ian A; Gaz, Dan V; Kakuk, Alynn C; Mack, Jessica L; Ver Mulm, Jacyln A

    2015-12-01

    Inspiratory muscle training (IMT) strengthens the muscles of respiration, improves breathing efficiency, and increases fitness. The IMT is generally performed independently of aerobic exercise; however, it is not clear whether there is added benefit of performing the IMT while simultaneously performing aerobic exercise in terms of activating and strengthening inspiratory muscles. The purpose of our study was to determine the effect of IMT on respiratory muscle electromyography (EMG) activity during stationary cycling in the upright and drops postures as compared with that when the IMT was performed alone. Diaphragm and sternocleidomastoid EMG activity was measured under different resting and cycling postures, with and without the use of the IMT at 40% maximal inspiratory pressure (n = 10; mean age 37). Cycling in an upright posture while simultaneously performing the IMT resulted in a significantly greater diaphragm EMG activity than while performing the IMT at rest in upright or drops postures (p ≤ 0.05). Cycling in drops postures while performing the IMT had a significantly greater diaphragm EMG activity than when performing the IMT at rest in either upright or drops postures (p ≤ 0.05). Sternocleidomastoid muscle activity increased with both cycling and IMT, although posture had little effect. These results support our hypothesis in that the IMT while cycling increases respiratory EMG activity to a significantly greater extent than when performing the IMT solely at rest, suggesting that the combination of IMT and cycling may provide an additive training effect.

  15. Environmental factors, immune changes and respiratory diseases in troops during military activities.

    PubMed

    Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Chciałowski, Andrzej; Korsak, Jolanta

    2013-06-01

    Combat operations in contemporary theaters of war, as well as combat training, are carried out in all parts of the world, typically in a harsh environment. Specific environmental conditions, such as heat, cold, high-altitudes, desert climates, as well as chemical and biological pollution of both the atmosphere and soil, together with over-exertion, food restrictions, sleep deprivation, and psychological stress can all result in changes in the immune system and the occurrence of associated diseases. Respiratory diseases are one of the most common health problems among military personnel participating in combat training or deployed to operations in areas characterized by difficult climatic and sanitary conditions. They are, therefore, one of the main reasons for military personnel requiring ambulant and hospital treatment. The aim of the study was to discuss the influence of environmental factors and the conditions in which active duty is performed on changes in the immune system and the occurrence of respiratory tract diseases in a military environment.

  16. Dependence of synchronized bursting activity on medium stirring and the perfusion rate in a cultured network of neurons

    NASA Astrophysics Data System (ADS)

    Heo, Ryoun; Kim, Hyun; Lee, Kyoung J.

    2016-05-01

    A cultured network of neurons coupled with a multi-electrode-array (MEA) recording system has been a useful platform for investigating various issues in neuroscience and engineering. The neural activity supported by the system can be sensitive to environmental fluctuations, for example, in the medium's nutrient composition, ph, and temperature, and to mechanical disturbances, yet this issue has not been the subject. Especially, a normal practice in maintaining neuronal cell cultures involves an intermittent sequence of medium exchanges, typically at a time interval of a few days, and one such sudden medium exchange is unavoidably accompanied by many unintended disturbances. Here, based on a quantitative time-series analysis of synchronized bursting events, we explicitly demonstrate that such a medium exchange can, indeed, bring a huge change in the existing neural activity. Subsequently, we develop a medium perfusion-stirring system and an ideal protocol that can be used in conjunction with a MEA recording system, providing long-term stability. Specifically, we systematically evaluate the effects of medium stirring and perfusion rates. Unexpectedly, even some vigorous mechanical agitations do not have any impacts on neural activity. On the other hand, too much replenishment ( e.g., 1.8 ml/day for a 1.8-ml dish) of neurobasal medium results in an excitotoxicity.

  17. Mitotane alters mitochondrial respiratory chain activity by inducing cytochrome c oxidase defect in human adrenocortical cells.

    PubMed

    Hescot, Ségolène; Slama, Abdelhamid; Lombès, Anne; Paci, Angelo; Remy, Hervé; Leboulleux, Sophie; Chadarevian, Rita; Trabado, Séverine; Amazit, Larbi; Young, Jacques; Baudin, Eric; Lombès, Marc

    2013-06-01

    Mitotane, 1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane is the most effective medical therapy for adrenocortical carcinoma, but its molecular mechanism of action remains poorly understood. Although mitotane is known to have mitochondrial (mt) effects, a direct link to mt dysfunction has never been established. We examined the functional consequences of mitotane exposure on proliferation, steroidogenesis, and mt respiratory chain, biogenesis and morphology, in two human adrenocortical cell lines, the steroid-secreting H295R line and the non-secreting SW13 line. Mitotane inhibited cell proliferation in a dose- and a time-dependent manner. At the concentration of 50 μM (14 mg/l), which corresponds to the threshold for therapeutic efficacy, mitotane drastically reduced cortisol and 17-hydroxyprogesterone secretions by 70%. This was accompanied by significant decreases in the expression of genes encoding mt proteins involved in steroidogenesis (STAR, CYP11B1, and CYP11B2). In both H295R and SW13 cells, 50 μM mitotane significantly inhibited (50%) the maximum velocity of the activity of the respiratory chain complex IV (cytochrome c oxidase (COX)). This effect was associated with a drastic reduction in steady-state levels of the whole COX complex as revealed by blue native PAGE and reduced mRNA expression of both mtDNA-encoded COX2 (MT-CO2) and nuclear DNA-encoded COX4 (COX4I1) subunits. In contrast, the activity and expression of respiratory chain complexes II and III were unaffected by mitotane treatment. Lastly, mitotane exposure enhanced mt biogenesis (increase in mtDNA content and PGC1α (PPARGC1A) expression) and triggered fragmentation of the mt network. Altogether, our results provide first evidence that mitotane induced a mt respiratory chain defect in human adrenocortical cells.

  18. Image-based cytometry reveals three distinct subsets of activated granulocytes based on phagocytosis and oxidative burst.

    PubMed

    McFarlin, Brian K; Williams, Randall R; Venable, Adam S; Dwyer, Karen C; Haviland, David L

    2013-08-01

    Granulocytes play a key role in innate immunity and the most common functional assays are phagocytosis and oxidative burst. The purpose of this technical note is to use image-based flow cytometry to divide activated granulocytes into unique subsets based on their degree of phagocytosis and oxidative burst in response to different experimental incubations. Prior to the experiments, all reagents were titered to determine the lowest dose that resulted in an acceptable signal to noise ratio. Heparinized, whole blood (100 µl) was mixed with one of two bioparticles (E. coli and S. aureus) and DHE (10 µg/ml) and incubated for 5, 10, 20, 40, 60, 80, 100, 120, and 140 min in a 37°C water bath. An additional tube kept on ice was used as a negative control. All subsequent processing steps were completed on ice in the dark to minimize additional activation of cells. After the 37°C incubation, N-ethylmaleimide (15 mM) was added to halt phagocytosis, preventing the uptake of additional microparticles. Suspensions were labeled with CD66b-APC and CD45-APCeFluor780 for 60 min and a fix/lyse solution was added. Prior to acquisition, 7AAD was added to stain nuclear DNA. A minimum of 5,000 granulocyte (CD66b+) events were acquired using a Millipore-Amnis FlowSight equipped with blue (488 nm, 60 mW), red (642 nm, 100 mW), and side scatter (785 nm, 12 mW) lasers. Samples were compensated and analyzed using Amnis IDEAS software (v.5.0.983.0). Image-based analysis allowed us to divide activated granulocytes into three distinct subsets, whose relative abundance changed as a function of both bioparticle type and incubation length. The method described in this technical note represents a potential novel adaptation to common methods of assessing granulocyte function. More research is needed to test and validate our image-based method in clinical conditions that impair granulocyte function.

  19. Infection-induced respiratory burst in BALB/c macrophages kills Leishmania guyanensis amastigotes through apoptosis: possible involvement in resistance to cutaneous leishmaniasis.

    PubMed

    Sousa-Franco, Junia; Araújo-Mendes, Erica; Silva-Jardim, Izaltina; L-Santos, Jane; Faria, Daniela R; Dutra, Walderez O; Horta, Maria de Fátima

    2006-02-01

    The immune mechanisms that underlie resistance and susceptibility to leishmaniasis are not completely understood for all species of Leishmania. It is becoming clear that the immune response, the parasite elimination by the host and, as a result, the outcome of the disease depend both on the host and on the species of the infecting Leishmania. Here, we analyzed the outcome of the infection of BALB/c mice with L. guyanensis in vivo and in vitro. We showed that BALB/c mice, which are a prototype of susceptible host for most species of Leishmania, dying from these infections, develop insignificant or no cutaneous lesions and eliminate the parasite when infected with promastigotes of L. guyanensis. In vitro, we found that thioglycollate-elicited BALB/c peritoneal macrophages, which are unable to eliminate L. amazonensis without previous activation with cytokines or lipopolysaccharide, can kill L. guyanensis amastigotes. This is the first report showing that infection of peritoneal macrophages with stationary phase promastigotes efficiently triggers innate microbicidal mechanisms that are effective in eliminating the amastigotes, without exogenous activation. We demonstrated that L. guyanensis amastigotes die inside the macrophages through an apoptotic process that is independent of nitric oxide and is mediated by reactive oxygen intermediates generated in the host cell during infection. This innate killing mechanism of macrophages may account for the resistance of BALB/c mice to infection by L. guyanensis.

  20. Functional biomimetic models for the active site in the respiratory enzyme cytochrome c oxidase.

    PubMed

    Collman, James P; Decréau, Richard A

    2008-11-07

    A functional analog of the active site in the respiratory enzyme, cytochrome c oxidase (CcO) reproduces every feature in CcO's active site: a myoglobin-like heme (heme a3), a distal tridentate imidazole copper complex (Cu(B)), a phenol (Tyr244), and a proximal imidazole. When covalently attached to a liquid-crystalline SAM film on an Au electrode, this functional model continuously catalyzes the selective four-electron reduction of dioxygen at physiological potential and pH, under rate-limiting electron flux (as occurs in CcO).

  1. Cardio-respiratory and daily activity monitor based on FMCW Doppler radar embedded in a wheelchair.

    PubMed

    Postolache, Octavian; Girão, Pedro Silva; Postolache, Gabriela; Gabriel, Joaquim

    2011-01-01

    Unobtrusive monitoring of the cardio-respiratory and daily activity for wheelchair users became nowadays an important challenge, considering population aging phenomena and the increasing of the elderly with chronic diseases that affect their motion capabilities. This work reports the utilization of FMCW (frequency modulated continuous wave) Doppler radar sensors embedded in a manual wheelchair to measure the cardiac and respiratory activities and the physical activity of the wheelchair user. Another radar sensor is included in the system in order to quantify the motor activity through the wheelchair traveled distance, when the user performs the manual operation of the wheelchair. A conditioning circuit including active filters and a microcontroller based primary processing module was designed and implemented to deliver the information through Bluetooth communication protocol to an Android OS tablet computer. The main capabilities of the software developed using Android SDK and Java were the signal processing of Doppler radar measurement channel signals, graphical user interface, data storage and Wi-Fi data synchronization with remote physiological and physical activity database.

  2. Acute and Chronic Treatments with Quetiapine Increase Mitochondrial Respiratory Chain Complex Activity in the Rat Brain.

    PubMed

    Ignácio, Zuleide M; Réus, Gislaine Z; Abelaira, Helena M; Titus, Stephanie E; Carlessi, Anelise S; da Luz, Jaine R; Matias, Beatriz I; Bruchchen, Livia; Carvalho-Silva, Milena; Gomes, Lara M; Rebelo, Joyce; Streck, Emilio L; Quevedo, João

    2015-01-01

    Several studies have found that the molecular mechanisms of mitochondrial energy metabolism are impaired in major depressive disorder (MDD). Classic antidepressants and atypical antipsychotics can alter the function of enzymes involved in adenosine triphosphate (ATP) metabolism. Quetiapine is an atypical antipsychotic that, in addition to having a therapeutic benefit in treating MDD, appears to exert antioxidant and neuroprotective effects. Therefore, we aimed to evaluate the acute and chronic effects of quetiapine on the activity of enzyme complexes I to IV of the mitochondrial respiratory chain and creatine kinase (CK) in brain regions involved with MDD. After a single dose or serial injections over 14 days of quetiapine (20, 40, and 80 mg) were administered, isolates from the pre- frontal cortex, hippocampus, amygdala and nucleus accumbens were analyzed for enzyme activity levels. The enzyme activity varied according to the dose, brain region, and acute or chronic dosing protocols. In general, complexes I-III activity was increased, especially after acute administration. Acute administration also increased the activity of complex IV and CK in the amygdala while complex I was inhibited in the prefrontal cortex and nucleus accumbens. These results suggest that quetiapine produces an increase in respiratory chain complex activity, which may be underlying its efficacy against psychiatric disorders and neuronal damage.

  3. JAK inhibitors prevent migration of rheumatoid arthritis neutrophils towards interleukin-8, but do not inhibit priming of the respiratory burst or ROS production.

    PubMed

    Mitchell, Thomas S; Moots, Robert J; Wright, Helen L

    2017-04-02

    Neutrophils play a crucial role in the pathophysiology of rheumatoid arthritis (RA), via the release of reactive oxygen species (ROS), proteases and cytokines. Orally-active JAK inhibitors (JAKi), e.g. baricitinib and tofacitinib, have high clinical efficacy in RA but are linked with neutropenia and increased infections. Our aim was to determine the effect of JAK inhibition with baricitinib and tofacitinib on healthy control and RA neutrophil lifespan and function. RA (n=7) and healthy control (n=7) neutrophils were treated with baricitinib or tofacitinib for 30 min, prior to incubation in the absence or presence of GM-CSF or IFNγ. JAKi prevented GM-CSF- and IFNγ-induced apoptosis delay in RA and healthy control neutrophils in a dose-dependent manner. Baricitinib decreased the rate of chemotaxis towards IL-8, but not fMLP, in RA neutrophils. Whilst healthy control neutrophils incubated with GM-CSF became primed to produce ROS in response to stimulation with fMLP and PMA, RA neutrophils produced increased levels of ROS without the need for priming. JAKi prevented ROS release from primed healthy control neutrophils in response to fMLP, but had no effect on ROS production by RA neutrophils. Baricitinib reversed GM-CSF priming of ROS production in response to fMLP in healthy control, but not RA, neutrophils. We conclude that incubation with JAKi prevents chemotaxis of RA neutrophils towards IL-8, but does not prevent the production of ROS or increase the level of apoptosis. This may be due to the in vivo exposure of RA neutrophils to priming agents other than those that activate JAK/STAT signalling. This article is protected by copyright. All rights reserved.

  4. Inhibition of respiratory syncytial virus replication and virus-induced p38 kinase activity by berberine.

    PubMed

    Shin, Han-Bo; Choi, Myung-Soo; Yi, Chae-Min; Lee, Jun; Kim, Nam-Jung; Inn, Kyung-Soo

    2015-07-01

    Respiratory syncytial virus (RSV) causes severe lower respiratory tract infection and poses a major public health threat worldwide. No effective vaccines or therapeutics are currently available; berberine, an isoquinoline alkaloid from various medicinal plants, has been shown to exert antiviral and several other biological effects. Recent studies have shown that p38 mitogen-activated protein kinase (MAPK) activity is implicated in infection by and replication of viruses such as RSV and the influenza virus. Because berberine has previously been implicated in modulating the activity of p38 MAPK, its effects on RSV infection and RSV-mediated p38 MAPK activation were examined. Replication of RSV in epithelial cells was significantly reduced by treatment with berberine. Berberine treatment caused decrease in viral protein and mRNA syntheses. Similar to previously reported findings, RSV infection caused phosphorylation of p38 MAPK at a very early time point of infection, and phosphorylation was dramatically reduced by berberine treatment. In addition, production of interleukin-6 mRNA upon RSV infection was significantly suppressed by treatment with berberine, suggesting the anti-inflammatory role of berberine during RSV infection. Taken together, we showed that berberine, a natural compound already proven to be safe for human consumption, suppresses the replication of RSV. In addition, the current study suggests that inhibition of RSV-mediated early p38 MAPK activation, which has been implicated as an early step in viral infection, as a potential molecular mechanism.

  5. Different NF-κB activation characteristics of human respiratory syncytial virus subgroups A and B.

    PubMed

    Wu, Weining; Macdonald, Andrew; Hiscox, Julian A; Barr, John N

    2012-03-01

    Human respiratory syncytial virus (HRSV) is a member of the family Paramyxoviridae, and is responsible for serious respiratory illness in infants, the elderly and the immunocompromised. HRSV exists as two distinct lineages known as subgroups A and B, which represent two lines of divergent evolution with extensive genetic and serologic differences. While both subgroup A and B viruses contribute to overall HRSV disease, subgroup A isolates are associated with both increased frequency and morbidity of infections, and reasons for this are unclear. HRSV disease is characterized by virus-mediated cell destruction in combination with extensive inflammatory and immune modulatory responses, and for HRSV subgroup A isolates, several of these signaling pathways are regulated through activation of the transcription factor NF-κB. In contrast, the NF-κB activation characteristics of HRSV subgroup B infection remain untested. Here, we performed a quantitative and comparative analysis of NF-κB activation in response to infection of both continuous and primary cell cultures with HRSV subgroup A and B isolates. Our results showed the model HRSV subgroup A isolate consistently induced increased NF-κB activation compared to its HRSV subgroup B counterpart. The differential NF-κB activation characteristics of HRSV subgroup A and B viruses may contribute to differences in their pathogenesis.

  6. Global alliance against chronic respiratory diseases in Italy (GARD-Italy): strategy and activities.

    PubMed

    Laurendi, Giovanna; Mele, Sonia; Centanni, Stefano; Donner, Claudio F; Falcone, Franco; Frateiacci, Sandra; Lazzeri, Marta; Mangiacavallo, Antonino; Indinnimeo, Luciana; Viegi, Giovanni; Pisanti, Paola; Filippetti, Giuseppe

    2012-01-01

    The steady increase in incidence of chronic respiratory disease (CRD) now constitutes a serious public health problem. CRDs are often underdiagnosed and many patients are not diagnosed until the CRD is too severe to prevent normal daily activities. The prevention of CRDs and reducing their social and individual impacts means modifying environmental and social factors and improving diagnosis and treatment. Prevention of risk factors (tobacco smoke, allergens, occupational agents, indoor/outdoor air pollution) will significantly impact on morbidity and mortality. The Italian Ministry of Health (MoH) has made respiratory disease prevention a top priority and is implementing a comprehensive strategy with policies against tobacco smoking, indoor/outdoor pollution, obesity, and communicable diseases. Presently these actions are not well coordinated. The Global Alliance against Chronic Respiratory Diseases (GARD), set up by the World Health Organization, envisages national bodies; the GARD initiative in Italy, launched 11/6/2009, represents a great opportunity for the MoH. Its main objective is to promote the development of a coordinated CRD program in Italy. Effective prevention implies setting up a health policy with the support of healthcare professionals and citizen associations at national, regional, and district levels. What is required is a true inter-institutional synergy: respiratory diseases prevention cannot and should not be the responsibility of doctors alone, but must involve politicians/policymakers, as well as the media, local institutions, and schools, etc. GARD could be a significant experience and a great opportunity for Italy to share the GARD vision of a world where all people can breathe freely.

  7. Actinobacillus pleuropneumoniae Possesses an Antiviral Activity against Porcine Reproductive and Respiratory Syndrome Virus

    PubMed Central

    Labrie, Josée; Hernandez Reyes, Yenney; Burciaga Nava, Jorge A.; Gagnon, Carl A.; Jacques, Mario

    2014-01-01

    Pigs are often colonized by more than one bacterial and/or viral species during respiratory tract infections. This phenomenon is known as the porcine respiratory disease complex (PRDC). Actinobacillus pleuropneumoniae (App) and porcine reproductive and respiratory syndrome virus (PRRSV) are pathogens that are frequently involved in PRDC. The main objective of this project was to study the in vitro interactions between these two pathogens and the host cells in the context of mixed infections. To fulfill this objective, PRRSV permissive cell lines such as MARC-145, SJPL, and porcine alveolar macrophages (PAM) were used. A pre-infection with PRRSV was performed at 0.5 multiplicity of infection (MOI) followed by an infection with App at 10 MOI. Bacterial adherence and cell death were compared. Results showed that PRRSV pre-infection did not affect bacterial adherence to the cells. PRRSV and App co-infection produced an additive cytotoxicity effect. Interestingly, a pre-infection of SJPL and PAM cells with App blocked completely PRRSV infection. Incubation of SJPL and PAM cells with an App cell-free culture supernatant is also sufficient to significantly block PRRSV infection. This antiviral activity is not due to LPS but rather by small molecular weight, heat-resistant App metabolites (<1 kDa). The antiviral activity was also observed in SJPL cells infected with swine influenza virus but to a much lower extent compared to PRRSV. More importantly, the PRRSV antiviral activity of App was also seen with PAM, the cells targeted by the virus in vivo during infection in pigs. The antiviral activity might be due, at least in part, to the production of interferon γ. The use of in vitro experimental models to study viral and bacterial co-infections will lead to a better understanding of the interactions between pathogens and their host cells, and could allow the development of novel prophylactic and therapeutic tools. PMID:24878741

  8. Activity of Tachykinin1-Expressing Pet1 Raphe Neurons Modulates the Respiratory Chemoreflex.

    PubMed

    Hennessy, Morgan L; Corcoran, Andrea E; Brust, Rachael D; Chang, YoonJeung; Nattie, Eugene E; Dymecki, Susan M

    2017-02-15

    Homeostatic control of breathing, heart rate, and body temperature relies on circuits within the brainstem modulated by the neurotransmitter serotonin (5-HT). Mounting evidence points to specialized neuronal subtypes within the serotonergic neuronal system, borne out in functional studies, for the modulation of distinct facets of homeostasis. Such functional differences, read out at the organismal level, are likely subserved by differences among 5-HT neuron subtypes at the cellular and molecular levels, including differences in the capacity to coexpress other neurotransmitters such as glutamate, GABA, thyrotropin releasing hormone, and substance P encoded by the Tachykinin-1 (Tac1) gene. Here, we characterize in mice a 5-HT neuron subtype identified by expression of Tac1 and the serotonergic transcription factor gene Pet1, referred to as the Tac1-Pet1 neuron subtype. Transgenic cell labeling showed Tac1-Pet1 soma resident largely in the caudal medulla. Chemogenetic [clozapine-N-oxide (CNO)-hM4Di] perturbation of Tac1-Pet1 neuron activity blunted the ventilatory response of the respiratory CO2 chemoreflex, which normally augments ventilation in response to hypercapnic acidosis to restore normal pH and PCO2Tac1-Pet1 axonal boutons were found localized to brainstem areas implicated in respiratory modulation, with highest density in motor regions. These findings demonstrate that the activity of a Pet1 neuron subtype with the potential to release both 5-HT and substance P is necessary for normal respiratory dynamics, perhaps via motor outputs that engage muscles of respiration and maintain airway patency. These Tac1-Pet1 neurons may act downstream of Egr2-Pet1 serotonergic neurons, which were previously established in respiratory chemoreception, but do not innervate respiratory motor nuclei.SIGNIFICANCE STATEMENT Serotonin (5-HT) neurons modulate physiological processes and behaviors as diverse as body temperature, respiration, aggression, and mood. Using genetic tools

  9. Antiadhesive and antibiofilm activity of hyaluronic acid against bacteria responsible for respiratory tract infections.

    PubMed

    Drago, Lorenzo; Cappelletti, Laura; De Vecchi, Elena; Pignataro, Lorenzo; Torretta, Sara; Mattina, Roberto

    2014-10-01

    To address the problem of limited efficacy of existing antibiotics in the treatment of bacterial biofilm, it is necessary to find alternative remedies. One candidate could be hyaluronic acid; this study therefore aimed to evaluate the in vitro antiadhesive and antibiofilm activity of hyaluronic acid toward bacterial species commonly isolated from respiratory infections. Interference exerted on bacterial adhesion was evaluated by using Hep-2 cells, while the antibiofilm activity was assessed by means of spectrophotometry after incubation of biofilm with hyaluronic acid and staining with crystal violet. Our data suggest that hyaluronic acid is able to interfere with bacterial adhesion to a cellular substrate in a concentration-dependent manner, being notably active when assessed as pure substance. Moreover, we found that Staphylococcus aureus biofilm was more sensitive to the action of hyaluronic acid than biofilm produced by Haemophilus influenzae and Moraxella catarrhalis. In conclusion, hyaluronic acid is characterized by notable antiadhesive properties, while it shows a moderate activity against bacterial biofilm. As bacterial adhesion to oral cells is the first step for colonization, these results further sustain the role of hyaluronic acid in prevention of respiratory infections.

  10. A novel peptide with potent and broad-spectrum antiviral activities against multiple respiratory viruses

    PubMed Central

    Zhao, Hanjun; Zhou, Jie; Zhang, Ke; Chu, Hin; Liu, Dabin; Poon, Vincent Kwok-Man; Chan, Chris Chung-Sing; Leung, Ho-Chuen; Fai, Ng; Lin, Yong-Ping; Zhang, Anna Jin-Xia; Jin, Dong-Yan; Yuen, Kwok-Yung; Zheng, Bo-Jian

    2016-01-01

    A safe, potent and broad-spectrum antiviral is urgently needed to combat emerging respiratory viruses. In light of the broad antiviral activity of β-defensins, we tested the antiviral activity of 11 peptides derived from mouse β-defensin-4 and found that a short peptide, P9, exhibited potent and broad-spectrum antiviral effects against multiple respiratory viruses in vitro and in vivo, including influenza A virus H1N1, H3N2, H5N1, H7N7, H7N9, SARS-CoV and MERS-CoV. The antiviral activity of P9 was attributed to its high-affinity binding to viral glycoproteins, as well as the abundance of basic amino acids in its composition. After binding viral particles through viral surface glycoproteins, P9 entered into cells together with the viruses via endocytosis and prevented endosomal acidification, which blocked membrane fusion and subsequent viral RNA release. This study has paved the avenue for developing new prophylactic and therapeutic agents with broad-spectrum antiviral activities. PMID:26911565

  11. In vitro activity of ABT-773 versus macrolides and quinolones against resistant respiratory tract pathogens.

    PubMed

    Dubois, J; St -Pierre, C

    2001-01-01

    ABT-773, a novel ketolide, was compared to erythromycin, azithromycin, clarithromycin, ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin, gatifloxacin, and gemifloxacin against antibiotic-resistant strains recently isolated from patients with respiratory tract infections. MICs were determined by agar dilution using standard NCCLS methodology. ABT-773 (MIC(90) 0.06 mg/L) was more active than the macrolides (MIC(90) > or = 2 mg/L) and fluoroquinolones (MIC(90) > or = 0.5 mg/L) against penicillin-resistant Streptococcus pneumoniae. The fluoroquinolones were the most active agents tested against beta-lactamase-positive Haemophilus influenzae (MIC(90) < or = 0.01-0.06 mg/L), against which ABT-773 (MIC(90) 4 mg/L) was comparable to azithromycin and two- and four-fold more active than erythromycin and clarithromycin, respectively. Against beta-lactamase positive Moraxella catarrhalis, the activity of ABT-773 (MIC(90) 0.06 mg/L) was comparable to gemifloxacin, trovafloxacin, levofloxacin, and ciprofloxacin (MIC(90) 0.03-0.06 mg/L) and 4- to eightfold greater than that of clarithromycin, gatifloxacin, and erythromycin. These data suggest ABT-773 could be a valuable compound for the treatment of respiratory tract infections, including those resistant to usual oral therapy.

  12. Dualism of oxidized lipoproteins in provoking and attenuating the oxidative burst in macrophages: role of peroxisome proliferator-activated receptor-gamma.

    PubMed

    Fischer, Barbara; von Knethen, Andreas; Brüne, Bernhard

    2002-03-15

    Activation and deactivation of macrophages are of considerable importance during the development of various disease states, atherosclerosis among others. Macrophage activation is achieved by oxidized lipoproteins (oxLDL) and is determined by oxygen radical (ROS) formation. The oxidative burst was measured by flow cytometry and quantitated by oxidation of the redox-sensitive dye dichlorodihydrofluorescein diacetate. Short-time stimulation dose-dependently elicited ROS formation. Diphenylene iodonium prevented ROS formation, thus pointing to the involvement of a NAD(P)H oxidase in producing reduced oxygen species. In contrast, preincubation of macrophages with oxLDL for 16 h showed an attenuated oxidative burst upon a second contact with oxLDL. Taking into account that oxLDL is an established peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist and considering the anti-inflammatory properties of PPARgamma, we went on and showed that a PPARgamma agonist such as ciglitazone attenuated ROS formation. Along that line, major lipid peroxidation products of oxLDL, such as 9- and 13-hydroxyoctadecadienoic acid, shared that performance. Supporting evidence that PPARgamma activation accounted for reduced ROS generation came from studies in which proliferator-activated receptor response element decoy oligonucleotides, but not a mutated oligonucleotide, supplied in front of oxLDL delivery regained a complete oxidative burst upon cell activation. We conclude that oxLDL not only elicits an oxidative burst upon first contact, but also promotes desensitization of macrophages via activation of PPARgamma. Desensitization of macrophages may have important consequences for the behavior of macrophages/foam cells in atherosclerotic lesions.

  13. Muscle Transcriptional Profile Based on Muscle Fiber, Mitochondrial Respiratory Activity, and Metabolic Enzymes

    PubMed Central

    Liu, Xuan; Du, Yang; Trakooljul, Nares; Brand, Bodo; Muráni, Eduard; Krischek, Carsten; Wicke, Michael; Schwerin, Manfred; Wimmers, Klaus; Ponsuksili, Siriluck

    2015-01-01

    Skeletal muscle is a highly metabolically active tissue that both stores and consumes energy. Important biological pathways that affect energy metabolism and metabolic fiber type in muscle cells may be identified through transcriptomic profiling of the muscle, especially ante mortem. Here, gene expression was investigated in malignant hyperthermia syndrome (MHS)-negative Duroc and Pietrian (PiNN) pigs significantly differing for the muscle fiber types slow-twitch-oxidative fiber (STO) and fast-twitch-oxidative fiber (FTO) as well as mitochondrial activity (succinate-dependent state 3 respiration rate). Longissimus muscle samples were obtained 24 h before slaughter and profiled using cDNA microarrays. Differential gene expression between Duroc and PiNN muscle samples were associated with protein ubiquitination, stem cell pluripotency, amyloid processing, and 3-phosphoinositide biosynthesis and degradation pathways. In addition, weighted gene co-expression network analysis within both breeds identified several co-expression modules that were associated with the proportion of different fiber types, mitochondrial respiratory activity, and ATP metabolism. In particular, Duroc results revealed strong correlations between mitochondrion-associated co-expression modules and STO (r = 0.78), fast-twitch glycolytic fiber (r = -0.98), complex I (r=0.72) and COX activity (r = 0.86). Other pathways in the protein-kinase-activity enriched module were positively correlated with STO (r=0.93), while negatively correlated with FTO (r = -0.72). In contrast to PiNN, co-expression modules enriched in macromolecule catabolic process, actin cytoskeleton, and transcription activator activity were associated with fiber types, mitochondrial respiratory activity, and metabolic enzyme activities. Our results highlight the importance of mitochondria for the oxidative capacity of porcine muscle and for breed-dependent molecular pathways in muscle cell fibers. PMID:26681915

  14. Transcriptional burst frequency and burst size are equally modulated across the human genome

    SciTech Connect

    Dar, Roy D.; Simpson, Michael L; Weinberger, Leor S.; Razooky, B; Cox, Chris D.; McCollum, James M.; Trimeloni, Tom; Singh, A

    2012-01-01

    Gene expression occurs either as an episodic process, characterized by pulsatile bursts or as a constitutive, Poisson-like accumulation of gene products. It is not clear which mode of gene expression (constitutive versus bursty) predominates across a genome or how transcriptional dynamics are influenced by genomic position and promoter sequence. Here, we use time-lapse fluorescence microscopy, building off of theoretical studies that exploit the time-resolved structure of stochastic fluctuations in gene expression, to develop a three-dimensional method for mapping underlying gene-regulatory mechanisms. Over 8,000 individual human genomic loci were analyzed, and at virtually all loci, episodic bursting as opposed to constitutive expression was found to be the predominant mode of expression. Quantitative analysis of the expression dynamics at these 8,000 loci indicates that both frequency and size of transcriptional bursts vary equally across the human genome independent of promoter sequence. Strikingly, weaker expression loci modulate burst frequency to increase activity, while stronger expression loci modulate burst size to increase activity. Transcriptional activators, such as TNF, generate similar patterns of change in burst frequency and burst size. In summary, transcriptional bursting dominates across the human genome, both burst frequency and burst size vary by chromosomal location, and transcriptional activators alter burst frequency and burst size, depending on the expression level of the locus.

  15. RADIAL ANGULAR MOMENTUM TRANSFER AND MAGNETIC BARRIER FOR SHORT-TYPE GAMMA-RAY-BURST CENTRAL ENGINE ACTIVITY

    SciTech Connect

    Liu Tong; Gu Weimin; Hou Shujin; Liang Enwei; Lei Weihua; Lin Lin; Zhang Shuangnan; Dai Zigao

    2012-11-20

    Soft extended emission (EE) following initial hard spikes up to 100 s was observed with Swift/BAT for about half of known short-type gamma-ray bursts (SGRBs). This challenges the conversional central engine models of SGRBs, i.e., compact star merger models. In the framework of black-hole-neutron-star merger models, we study the roles of radial angular momentum transfer in the disk and the magnetic barrier around the black hole in the activity of SGRB central engines. We show that radial angular momentum transfer may significantly prolong the lifetime of the accretion process, which may be divided into multiple episodes by the magnetic barrier. Our numerical calculations based on models of neutrino-dominated accretion flows suggest that disk mass is critical for producing the observed EE. In the case of the mass being {approx}0.8 M {sub Sun }, our model can reproduce the observed timescale and luminosity of both the main and the EE episodes in a reasonable parameter set. The predicted luminosity of the EE component is lower than the observed EE within about one order of magnitude and the timescale is shorter than 20 s if the disk mass is {approx}0.2 M {sub Sun }. Swift/BAT-like instruments may be not sensitive enough to detect the EE component in this case. We argue that the EE component could be a probe for the merger process and disk formation for compact star mergers.

  16. Epidemic activity of respiratory syncytial virus is related to temperature and rainfall in equatorial tropical countries.

    PubMed

    Gamba-Sanchez, N; Rodriguez-Martinez, C E; Sossa-Briceño, M P

    2016-07-01

    Although viral acute lower respiratory infections (ALRIs) are a major public health problem in tropical low- and middle-income countries (LMICs), and there is growing evidence showing their relationship with meteorological parameters, studies performed in these countries are scarce. In an analytical cross-sectional study, we determined which of the main meteorological parameters (temperature, absolute humidity, rainfall, wind speed, and solar radiation) predicted respiratory syncytial virus (RSV) activity in a population of hospitalized children with ALRI during a 5-year period, from January 2009 to December 2013. Out of a total of 4559 children included in the study (mean age 9·2 ± 8·5 months), 2953 (64·8%) presented RSV infection during the 3-month period from March to May. In the multivariate analysis, after controlling for absolute humidity, wind speed, and solar radiation, temperature [incidence rate ratio (IRR) 2·25, 95% confidence interval (CI) 1·11-4·53, P = 0·024], and rainfall (IRR 1·01, 95% CI 1·00-1·02, P = 0·044) were independently associated with the monthly number of RSV infections. In conclusion, in Bogota, the capital of a tropical LMIC lying slightly above the equator, RSV activity peaks in the 3-month period from March to May, the main rainy period of the year in the city. In addition, rainfall and temperature are the two most important meteorological parameters that are independently associated with RSV activity in hospitalized children with ALRI in the city.

  17. Products of Submarine Fountains and Bubble-burst Eruptive Activity at 1200 m on West Mata Volcano, Lau Basin

    NASA Astrophysics Data System (ADS)

    Clague, D. A.; Rubin, K. H.; Keller, N. S.

    2009-12-01

    An eruption was observed and sampled at West Mata Volcano using ROV JASON II for 5 days in May 2009 during the NSF-NOAA eruption response cruise to this region of suspected volcanic activity. Activity was focused near the summit at the Prometheus and Hades vents. Prometheus erupted almost exclusively as low-level fountains. Activity at Hades cycled between vigorous degassing, low fountains, and bubble-bursts, building up and partially collapsing a small spatter/scoria cone and feeding short sheet-like and pillow flows. Fire fountains at Prometheus produced mostly small primary pyroclasts that include Pele's hair and fluidal fragments of highly vesicular volcanic glass. These fragments have mostly shattered and broken surfaces, although smooth spatter-like surfaces also occur. As activity wanes, glow in the vent fades, and denser, sometimes altered volcanic clasts are incorporated into the eruption. The latter are likely from the conduit walls and/or vent-rim ejecta, drawn back into the vent by inrushing seawater that replaces water entrained in the rising volcanic plume. Repeated recycling of previously erupted materials eventually produces rounded clasts resembling beach cobbles and pitted surfaces on broken phenocrysts of pyroxene and olivine. We estimate that roughly 33% of near vent ejecta are recycled. Our best sample of this ejecta type was deposited in the drawer of the JASON II ROV during a particularly large explosion that occurred during plume sampling immediately above the vent. Elemental sulfur spherules up to 5 mm in diameter are common in ejecta from both vents and occur inside some of the lava fragments Hades activity included dramatic bubble-bursts unlike anything previously observed under water. The lava bubbles, sometimes occurring in rapid-fire sequence, collapsed in the water-column, producing fragments that are quenched in less than a second to form Pele's hair, limu o Pele, spatter-like lava blobs, and scoria. All are highly vesicular

  18. In vitro activity and rodent efficacy of clinafloxacin for bovine and swine respiratory disease

    PubMed Central

    Sweeney, Michael T.; Quesnell, Rebecca; Tiwari, Raksha; LeMay, Mary; Watts, Jeffrey L.

    2013-01-01

    Clinafloxacin is a broad-spectrum fluoroquinolone that was originally developed and subsequently abandoned in the late 1990s as a human health antibiotic for respiratory diseases. The purpose of this study was to investigate the activity of clinafloxacin as a possible treatment for respiratory disease in cattle and pigs. Minimum inhibitory concentration (MIC) values were determined using Clinical and Laboratory Standards Institute recommended procedures with recent strains from the Zoetis culture collection. Rodent efficacy was determined in CD-1 mice infected systemically or intranasally with bovine Mannheimia haemolytica or Pasteurella multocida, or swine Actinobacillus pleuropneumoniae, and administered clinafloxacin for determination of ED50 (efficacious dose-50%) values. The MIC90 values for clinafloxacin against bovine P. multocida, M. haemolytica, Histophilus somni, and M. bovis were 0.125, 0.5, 0.125, and 1 μg/ml, respectively, and the MIC90 values against swine P. multocida, A. pleuropneumoniae, S. suis, and M. hyopneumoniae were í0.03, í0.03, 0.125, and í0.008 μg/ml, respectively. Efficacy in mouse models showed average ED50 values of 0.019 mg/kg/dose in the bovine M. haemolytica systemic infection model, 0.55 mg/kg in the bovine P. multocida intranasal lung challenge model, 0.08 mg/kg/dose in the bovine P. multocida systemic infection model, and 0.7 mg/kg/dose in the swine A. pleuropneumoniae systemic infection model. Clinafloxacin shows good in vitro activity and efficacy in mouse models and may be a novel treatment alternative for the treatment of respiratory disease in cattle and pigs. PMID:23785362

  19. In vitro activity and rodent efficacy of clinafloxacin for bovine and swine respiratory disease.

    PubMed

    Sweeney, Michael T; Quesnell, Rebecca; Tiwari, Raksha; Lemay, Mary; Watts, Jeffrey L

    2013-01-01

    Clinafloxacin is a broad-spectrum fluoroquinolone that was originally developed and subsequently abandoned in the late 1990s as a human health antibiotic for respiratory diseases. The purpose of this study was to investigate the activity of clinafloxacin as a possible treatment for respiratory disease in cattle and pigs. Minimum inhibitory concentration (MIC) values were determined using Clinical and Laboratory Standards Institute recommended procedures with recent strains from the Zoetis culture collection. Rodent efficacy was determined in CD-1 mice infected systemically or intranasally with bovine Mannheimia haemolytica or Pasteurella multocida, or swine Actinobacillus pleuropneumoniae, and administered clinafloxacin for determination of ED50 (efficacious dose-50%) values. The MIC90 values for clinafloxacin against bovine P. multocida, M. haemolytica, Histophilus somni, and M. bovis were 0.125, 0.5, 0.125, and 1 μg/ml, respectively, and the MIC90 values against swine P. multocida, A. pleuropneumoniae, S. suis, and M. hyopneumoniae were í0.03, í0.03, 0.125, and í0.008 μg/ml, respectively. Efficacy in mouse models showed average ED50 values of 0.019 mg/kg/dose in the bovine M. haemolytica systemic infection model, 0.55 mg/kg in the bovine P. multocida intranasal lung challenge model, 0.08 mg/kg/dose in the bovine P. multocida systemic infection model, and 0.7 mg/kg/dose in the swine A. pleuropneumoniae systemic infection model. Clinafloxacin shows good in vitro activity and efficacy in mouse models and may be a novel treatment alternative for the treatment of respiratory disease in cattle and pigs.

  20. Does breathing type influence electromyographic activity of obligatory and accessory respiratory muscles?

    PubMed

    Gutiérrez, M F; Valenzuela, S; Miralles, R; Portus, C; Santander, H; Fuentes, A D; Celhay, I

    2014-11-01

    Craniomandibular electromyographic (EMG) studies frequently include several parameters, e.g. resting, chewing and tooth-clenching. EMG activity during these parameters has been recorded in the elevator muscles, but little is known about the respiratory muscles. The aim of this study was to compare EMG activity in obligatory and accessory respiratory muscles between subjects with different breathing types. Forty male subjects were classified according to their breathing type into two groups of 20 each: costo-diaphragmatic breathing type and upper costal breathing type. Bipolar surface electrodes were placed on the sternocleidomastoid, diaphragm, external intercostal and latissimus dorsi muscles. EMG activity was recorded during the following tasks: (i) normal quiet breathing, (ii) maximal voluntary clenching in intercuspal position, (iii) natural rate chewing until swallowing threshold, (iv) short-time chewing. Diaphragm EMG activity was significantly higher in the upper costal breathing type than in the costo-diaphragmatic breathing type in all tasks (P < 0·05). External intercostal EMG activity was significantly higher in the upper costal breathing type than in the costo-diaphragmatic breathing type in tasks 3 and 4 (P < 0·05). Sternocleidomastoid and latissimus dorsi EMG activity did not show significant differences between breathing types in the tasks studied (P > 0·05). The significantly higher EMG activity observed in subjects with upper costal breathing than in the costo-diaphragmatic breathing type suggests that there could be differences in motor unit recruitment strategies depending on the breathing type. This may be an expression of the adaptive capability of muscle chains in subjects who clinically have a different thoraco-abdominal expansion during inspiration at rest.

  1. [Effect of change in activity level of catecholaminergic systems on motor, respiratory, and cardiac activities in rat embryos].

    PubMed

    Timofeeva, O P; Vdovichenko, N D; Kuznetsov, S V

    2012-01-01

    Parameters of motor, respiratory and cardiac activities were studied in rat embryos (E17-20) after changes in activity level of catecholaminergic systems. To produce conditions for excessive level of catecholamines, the animal were administered individually with preparation of L-DOPA at doses of 25, 50 and 100 mg/kg. Also studied was action of L-DOPA after blockade of D1-(antagonist - SCH-23390, 0.1 mg/kg), D2-(antagonist - sulpiride, 50 mg/kg) dopaminic, and beta2-(antagonist - propranolol, 1 mg/kg) adrenergic receptors. It was found out in E17-18 that the DOPA administration regardless of dose, while in E19-20 dose-dependently produces continuous generalized activity. Between E18 and E19, ontogenetically new is the appearance in 92 % of embryos of stereotypical head movements (circular movements, lateral and dorso-ventral flexions) following in the nearsecond rhythm. Injection of DOPA to rat embryos increased 2-6 times the number of respiratory movements by the gasping type in E17-20 and decreased the amount of episodes of continuous rhythmical respiration in E19-20. No significant heart rate changes were observed after introduction of DOPA to E17-20. There was noted a tendency for a weak acceleration of the heart rate. The changes in activities of the motor and respiratory systems due to a rise of catecholamine level are not connected with activation of the dopamine system, as they are not reduced by blockade of dopamine receptors.

  2. Three brainstem areas involved in respiratory rhythm generation in bullfrogs

    PubMed Central

    Baghdadwala, Mufaddal I; Duchcherer, Maryana; Paramonov, Jenny; Wilson, Richard J A

    2015-01-01

    an additional brainstem region that generates the priming phase. This Priming Area extends rostral and caudal of the Lung Area and is distinct from the Buccal Area. Using AMPA microinjections and reversible synaptic blockade, we demonstrate selective excitation and ablation (respectively) of priming phase activity. We also demonstrate that the Priming Area contains neurons active selectively during the priming phase. Thus, we propose that three distinct neuronal components generate the multiphase respiratory motor pattern produced by the frog brainstem: the buccal, priming and powerstroke burst generators. This raises the possibility that a similar multi-burst generator architecture mediates the three distinct phases of ventilation in mammals. PMID:25952282

  3. [Alpha-bursts and K-complex: phasic activation pattern during spontaneous recovery of correct psychomotor performance at difference stages of drowsiness].

    PubMed

    Dorokhov, V B

    2003-01-01

    It is known that phasic activation processes reveal themselves by different electrophysiological patterns depending on the sleep depth. Alpha bursts are an electrophysiological manifestation of arousal at the initial stage of sleep, whereas at the II stage K-complex becomes the main arousal pattern. We have shown earlier that during light drowsiness spontaneous recovery of correct psychomotor test performance (after an error) by a sitting subject is accompanied by EEG alpha bursts. The aim of this work was to study the EEG phasic activation pattern at deeper drowsiness during test performance by a subject in a lying position. Subjects had to press sensitive button in a lying position with closed eyes with self-paced oral counting of pressings. The experiment lasted for 40 min; EEG, EOG, and button pressing were recorded. It was shown that recovery of correct performance after errors at deeper drowsiness was accompanied by two types of EEG phasic activation patterns (PAP-1 and PAP-2). The alpha frequency component was always present in both PAP-1 and PAP-2. PAP-1 were observed at early stages of drowsiness and consisted of high-amplitude alpha bursts and EEG activity of higher frequency. PAP-2 were recorded at deeper stages and consisted of K-complexes with superposition of PAP-1. At first (medium level of drowsiness) the alpha bursts were superposed on the late slow K-complex components. With further deepening of drowsiness the early fast components of K-complex were also observed. The early appearance of K-complex during test performance at drowsiness seems to be associated with the urgent run of brain arousal systems, which at spontaneous falling asleep are in operation at the II sleep stage.

  4. Transitions to Synchrony in Coupled Bursting Neurons

    NASA Astrophysics Data System (ADS)

    Dhamala, Mukeshwar; Jirsa, Viktor K.; Ding, Mingzhou

    2004-01-01

    Certain cells in the brain, for example, thalamic neurons during sleep, show spike-burst activity. We study such spike-burst neural activity and the transitions to a synchronized state using a model of coupled bursting neurons. In an electrically coupled network, we show that the increase of coupling strength increases incoherence first and then induces two different transitions to synchronized states, one associated with bursts and the other with spikes. These sequential transitions to synchronized states are determined by the zero crossings of the maximum transverse Lyapunov exponents. These results suggest that synchronization of spike-burst activity is a multi-time-scale phenomenon and burst synchrony is a precursor to spike synchrony.

  5. MSFC Respiratory Protection Services

    NASA Technical Reports Server (NTRS)

    CoVan, James P.

    1999-01-01

    An overview of the Marshall Space Flight Center Respiratory Protection program is provided in this poster display. Respiratory protection personnel, building, facilities, equipment, customers, maintenance and operational activities, and Dynatech fit testing details are described and illustrated.

  6. Interactive effects of social adversity and respiratory sinus arrhythmia activity on reactive and proactive aggression.

    PubMed

    Zhang, Wei; Gao, Yu

    2015-10-01

    Abnormal parasympathetic nervous system (PNS)-related cardiac activity has been linked to aggression. However, little is known about how it interacts with psychosocial adversity in predisposing to reactive-proactive aggression. In the current study, 84 male and female college students self-reported reactive and proactive aggression, and were assessed for respiratory sinus arrhythmia (RSA), a measure of PNS-related cardiac activity, during rest and when they contemplated an emotion-evoking decision-making task. Regression analyses showed that (a) resting RSA was positively linked to reactive aggression in conditions of high social adversity, and (b) RSA reactivity was positively associated with reactive but negatively associated with proactive aggression, in conditions of low social adversity. Main effects were not found for psychophysiological functioning or psychosocial adversity, suggesting the importance of their interaction. Findings support a biosocial basis for aggression and add additional support for the distinctions between reactive and proactive aggression.

  7. The 60 Month All-Sky Burst Alert Telescope Survey of Active Galactic Nucleus and the Anisotropy of Nearby AGNs

    NASA Technical Reports Server (NTRS)

    Ajello, M.; Alexander, D. M.; Greiner, J.; Madejeski, G. M.; Gehrels, N.; Burlon, D.

    2014-01-01

    Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). We present the results of 60 months of observation of the hard X-ray sky with Swift/Burst Alert Telescope (BAT). In this time frame, BAT-detected (in the 15-55 keV band) 720 sources in an all-sky survey of which 428 are associated with AGNs, most of which are nearby. Our sample has negligible incompleteness and statistics a factor of approx. 2 larger over similarly complete sets of AGNs. Our sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent approx. 5% of AGN samples detected above 15 keV. We use the BAT data set to refine the determination of the log N-log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. We show that the log N-log S of AGNs selected above 10 keV is now established to approx. 10% precision. We derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9(+4.1/-2.9)× 10(exp -5)/cubic Mpc for objects with a de-absorbed luminosity larger than 2 × 10(exp 42) erg / s. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. We find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (much < 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions..

  8. Respiratory muscle activity and patient–ventilator asynchrony during different settings of noninvasive ventilation in stable hypercapnic COPD: does high inspiratory pressure lead to respiratory muscle unloading?

    PubMed Central

    Duiverman, Marieke L; Huberts, Anouk S; van Eykern, Leo A; Bladder, Gerrie; Wijkstra, Peter J

    2017-01-01

    Introduction High-intensity noninvasive ventilation (NIV) has been shown to improve outcomes in stable chronic obstructive pulmonary disease patients. However, there is insufficient knowledge about whether with this more controlled ventilatory mode optimal respiratory muscle unloading is provided without an increase in patient–ventilator asynchrony (PVA). Patients and methods Ten chronic obstructive pulmonary disease patients on home mechanical ventilation were included. Four different ventilatory settings were investigated in each patient in random order, each for 15 min, varying the inspiratory positive airway pressure and backup breathing frequency. With surface electromyography (EMG), activities of the intercostal muscles, diaphragm, and scalene muscles were determined. Furthermore, pressure tracings were derived simultaneously in order to assess PVA. Results Compared to spontaneous breathing, the most pronounced decrease in EMG activity was achieved with the high-pressure settings. Adding a high breathing frequency did reduce EMG activity per breath, while the decrease in EMG activity over 1 min was comparable with the high-pressure, low-frequency setting. With high backup breathing frequencies less breaths were pressure supported (25% vs 97%). PVAs occurred more frequently with the low-frequency settings (P=0.017). Conclusion High-intensity NIV might provide optimal unloading of respiratory muscles, without undue increases in PVA. PMID:28138234

  9. Effect of nitric oxide on mitochondrial respiratory activity of human articular chondrocytes

    PubMed Central

    Maneiro, E; Lopez-Armada, M; de Andres, M C; Carames, B; Martin, M; Bonilla, A; del Hoyo, P; Galdo, F; Arenas, J; Blanco, F

    2005-01-01

    Objective: To investigate the effect of nitric oxide (NO) on mitochondrial activity and its relation with the apoptosis of human articular chondrocytes. Materials and methods: Mitochondrial function was evaluated by analysing respiratory chain enzyme complexes, citrate synthase (CS) activities, and mitochondrial membrane potential (Δψm). The activities of the mitochondrial respiratory chain (MRC) complexes (complex I: NADH CoQ1 reductase, complex II: succinate dehydrogenase, complex III: ubiquinol cytochrome c reductase, complex IV: cytochrome c oxidase) and CS were measured in human articular chondrocytes isolated from normal cartilage. The Δψm was measured by 5,5',6,6'-tetracholoro-1,1',3,3'-tetraethylbenzimidazole carbocyanide iodide (JC-1) using flow cytometry. Apoptosis was analysed by flow cytometry. The mRNA expression of caspases was analysed by ribonuclease protection analysis and the detection of protein synthesis by western blotting. Sodium nitroprusside (SNP) was used as an NO compound donor. Results: SNP at concentrations higher than 0.5 mmol/l for 24 hours induced cellular changes characteristic of apoptosis. SNP elicited mRNA expression of caspase-3 and caspase-7 and down regulated bcl-2 synthesis in a dose and time dependent manner. Furthermore, 0.5 mM SNP induced depolarisation of the mitochondrial membrane at 5, 12, and 24 hours. Analysis of the MRC showed that at 5 hours, 0.5 mM SNP reduced the activity of complex IV by 33%. The individual inhibition of mitochondrial complex IV with azide modified the Δψm and induced apoptosis. Conclusions: This study suggests that the effect of NO on chondrocyte survival is mediated by its effect on complex IV of the MRC. PMID:15708893

  10. Prevalence and Impact of Active and Passive Cigarette Smoking in Acute Respiratory Distress Syndrome

    PubMed Central

    Hsieh, S. Jean; Zhuo, Hanjing; Benowitz, Neal L.; Thompson, B. Taylor; Liu, Kathleen D.; Matthay, Michael A.; Calfee, Carolyn S.

    2014-01-01

    Objective Cigarette smoke exposure has recently been found to be associated with increased susceptibility to trauma- and transfusion-associated acute respiratory distress syndrome (ARDS). We sought to determine 1) the prevalence of cigarette smoke exposure in a diverse multi-center sample of ARDS patients, and 2) whether cigarette smoke exposure is associated with severity of lung injury and mortality in ARDS. Design Analysis of the Albuterol for the Treatment of ALI (ALTA) and Omega ARDS Network studies. Setting Acute Respiratory Distress Syndrome Network hospitals. Patients Three hundred eighty one patients with ARDS. Interventions None. Measurements NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol), a validated tobacco-specific marker, was measured in urine samples from subjects enrolled in two NHLBI ARDS Network randomized controlled trials. Main Results Urine NNAL levels were consistent with active smoking in 36% of ARDS patients and with passive smoking in 41% of nonsmokers (vs 20% and 40% in general population, respectively). Patients with NNAL levels in the active smoking range were younger and had a higher prevalence of alcohol misuse, fewer comorbidities, lower severity of illness, and less septic shock at enrollment compared to patients with undetectable NNAL levels. Despite this lower severity of illness, the severity of lung injury did not significantly differ based on biomarker-determined smoking status. Cigarette smoke exposure was not significantly associated with death after adjusting for differences in age, alcohol use, comorbidities, and severity of illness. Conclusions In this first multicenter study of biomarker-determined cigarette smoke exposure in ARDS patients, we found that active cigarette smoke exposure was significantly more prevalent among ARDS patients compared to population averages. Despite their younger age, better overall health, and lower severity of illness, smokers by NNAL had similar severity of lung injury as patients with

  11. Expanding Voluntary Active-learning Opportunities for Pharmacy Students in a Respiratory Physiology Module

    PubMed Central

    Ernst, Hardy; Colthorpe, Kay

    2008-01-01

    Objectives To expand voluntary active-learning opportunities for bachelor of pharmacy students enrolled in a third-year human physiology and pharmacology course and determine whether the additional course components improved learning outcomes. Design Additional voluntary active-learning opportunities including a large-class tutorial, additional formative assessment, and an online discussion were added to the Respiratory Physiology Module of the course. Examination scores were compared with those from previous years. A questionnaire was administered to assess students' perception of the active-learning components. Assessment Mean examination scores increased from 69.3% ± 24.4% in 2003 to 88.9% ± 13.4% in 2004 and 86.9% ± 17.6% in 2005, after the addition of the active-learning components. Students' overall perception of the value of the active-learning activities was positive. Summary The addition of voluntary active-learning course components to a required pharmacy course resulted in improved student examination scores, and decreased failure rate, and were accomplished at low cost and with little additional staff time. PMID:18483596

  12. Sirtuin 1 Regulates Dendritic Cell Activation and Autophagy during Respiratory Syncytial Virus-Induced Immune Responses.

    PubMed

    Owczarczyk, Anna B; Schaller, Matthew A; Reed, Michelle; Rasky, Andrew J; Lombard, David B; Lukacs, Nicholas W

    2015-08-15

    Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in children worldwide. Sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, has been associated with the induction of autophagy and the regulation of inflammatory mediators. We found that Sirt1 was upregulated in mouse lung after RSV infection. Infected animals that received EX-527, a selective SIRT1 inhibitor, displayed exacerbated lung pathology, with increased mucus production, elevated viral load, and enhanced Th2 cytokine production. Gene expression analysis of isolated cell populations revealed that Sirt1 was most highly upregulated in RSV-treated dendritic cells (DCs). Upon RSV infection, EX-527-treated DCs, Sirt1 small interfering RNA-treated DCs, or DCs from conditional knockout (Sirt1(f/f)-CD11c-Cre(+)) mice showed downregulated inflammatory cytokine gene expression and attenuated autophagy. Finally, RSV infection of Sirt1(f/f)-CD11c-Cre(+) mice resulted in altered lung and lymph node cytokine responses, leading to exacerbated pathology. These data indicate that SIRT1 promotes DC activation associated with autophagy-mediated processes during RSV infection, thereby directing efficient antiviral immune responses.

  13. Influence of respiratory motor neurone activity on human autonomic and haemodynamic rhythms

    NASA Technical Reports Server (NTRS)

    Gonschorek, A. S.; Lu, L. L.; Halliwill, J. R.; Beightol, L. A.; Taylor, J. A.; Painter, J. A.; Warzel, H.; Eckberg, D. L.

    2001-01-01

    Although humans hold great advantages over other species as subjects for biomedical research, they also bring major disadvantages. One is that among the many rhythmic physiological signals that can be recorded, there is no sure way to know which individual change precedes another, or which change represents cause and which represents effect. In an attempt to deal with the inherent complexity of research conducted in intact human subjects, we developed and used a structural equation model to analyse responses of healthy young men to pharmacological changes of arterial pressure and graded inspiratory resistance, before and after vagomimetic atropine. Our model yielded a good fit of the experimental data, with a system weighted R2 of 0.77, and suggested that our treatments exerted both direct and indirect influences on the variables we measured. Thus, infusions of nitroprusside and phenylephrine exerted all of their direct effects by lowering and raising arterial pressure; the changes of R-R intervals, respiratory sinus arrhythmia and arterial pressure fluctuations that these drugs provoked, were indirect consequences of arterial pressure changes. The only direct effect of increased inspiratory resistance was augmentation of arterial pressure fluctuations. These results may provide a new way to disentangle and understand responses of intact human subjects to experimental forcings. The principal new insight we derived from our modelling is that respiratory gating of vagal-cardiac motor neurone firing is nearly maximal at usual levels of arterial pressure and inspiratory motor neurone activity.

  14. c-Jun N-terminal kinase activity is required for efficient respiratory syncytial virus production.

    PubMed

    Caly, Leon; Li, Hong-Mei; Bogoyevitch, Marie A; Jans, David A

    2017-01-29

    Respiratory syncytial virus (RSV) is a major cause of respiratory infections in infants and the elderly, leading to more deaths than influenza each year worldwide. With no RSV antiviral or efficacious vaccine currently available, improved understanding of the host-RSV interaction is urgently required. Here we examine the contribution to RSV infection of the host stress-regulated c-Jun N-terminal kinase (JNK), for the first time. Peak JNK1/2 phosphoactivation is observed at ∼24 h post-infection, correlating with the time of virus assembly. The release of infectious RSV virions from infected cells was significantly reduced by either JNK1/2 siRNA knockdown or treatment with the JNK-specific inhibitor, JNK-IN-VIII. High resolution microscopy confirmed RSV accumulation in the host cell cytoplasm. The results implicate JNK1/2 as a key host factor for RSV virus production, raising the possibility of agents targeting JNK activity as potential anti-RSV therapeutics.

  15. Cooperativity and flexibility of the protonmotive activity of mitochondrial respiratory chain.

    PubMed

    Papa, Sergio; Lorusso, Michele; Di Paola, Marco

    2006-01-01

    Functional and structural data are reviewed which provide evidence that proton pumping in cytochrome c oxidase is associated with extended allosteric cooperativity involving the four redox centers in the enzyme . Data are also summarized showing that the H+/e- stoichiometry for proton pumping in the cytochrome span of the mitochondrial respiratory chain is flexible. The DeltapH component of the bulk-phase membrane electrochemical proton gradient exerts a decoupling effect on the proton pump of both the bc1 complex and cytochrome c oxidase. A slip in the pumping efficiency of the latter is also caused by high electron pressure. The mechanistic and physiological implications of proton-pump slips are examined. The easiness with which bulk phase DeltapH causes, at least above a threshold level, decoupling of proton pumping indicates that for active oxidative phosphorylation efficient protonic coupling between redox complexes and ATP synthase takes place at the membrane surface, likely in cristae, without significant formation of delocalized DeltamuH+. A role of slips in modulating oxygen free radical production by the respiratory chain and the mitochondrial pathway of apoptosis is discussed.

  16. Effects of hypercapnia and inspiratory flow-resistive loading on respiratory activity in chronic airways obstruction.

    PubMed Central

    Altose, M D; McCauley, W C; Kelsen, S G; Cherniack, N S

    1977-01-01

    The respiratory responses to hypercapnia alone and to hypercapnia and flow-resistive loading during inspiration were studied in normal individuals and in eucapnic and hypercapnic patients with chronic airways obstruction. Responses were assessed in terms of minute ventilation and occlusion pressure (mouth pressure during airway occlusion 100 ms after the onset of inspiration). Ventilatory responses to CO2 (deltaV/deltaPCO2) were distinctly subnormal in both groups of patients with airways obstruction. The two groups of patients, however, showed different occlusion pressure responses to CO2 (deltaP100/deltaPCO2): deltaP100/deltaPCO2 was normal in the eucapnic patients but subnormal in the hypercapnic patients. Flow-resistive loading during inspiration reduced deltaV/deltaPCO2 both in normal subjects and in patients with airways obstruction. The occlusion pressure response to CO2 increased in normal subjects during flow-resistive loading but remained unchanged in both groups of patients with chronic airways obstruction. These results indicate that while chemosensitivity as determined by deltaP100/deltaPCO2 is impaired only in hypercapnic patients with chronic airways obstruction, an acute increase in flow resistance elicits a subnormal increase in respiratory efferent activity in both eucapnic and hypercapnic patients. PMID:838862

  17. Anesthetic activation of central respiratory chemoreceptor neurons involves inhibition of a THIK-1-like background K+ current

    PubMed Central

    Lazarenko, Roman M.; Fortuna, Michal G.; Shi, Yingtang; Mulkey, Daniel K.; Takakura, Ana C.; Moreira, Thiago S.; Guyenet, Patrice G.; Bayliss, Douglas A.

    2010-01-01

    At surgical depths of anesthesia, inhalational anesthetics cause a loss of motor response to painful stimuli (i.e., immobilization) that is characterized by profound inhibition of spinal motor circuits. Yet, although clearly depressed, the respiratory motor system continues to provide adequate ventilation under these same conditions. Here, we show that isoflurane causes robust activation of CO2/pH-sensitive, Phox2b-expressing neurons located in the retrotrapezoid nucleus (RTN) of the rodent brainstem, in vitro and in vivo. In brainstem slices from Phox2b-eGFP mice, the firing of pH-sensitive RTN neurons was strongly increased by isoflurane, independent of prevailing pH conditions. At least two ionic mechanisms contributed to anesthetic activation of RTN neurons: activation of a Na+-dependent cationic current and inhibition of a background K+ current. Single cell RT-PCR analysis of dissociated GFP-labeled RTN neurons revealed expression of THIK-1 (K2P13.1), a channel that shares key properties with the native RTN current (i.e., suppression by inhalational anesthetics, weak rectification, inhibition by extracellular Na+, and pH-insensitivity). Isoflurane also increased firing rate of RTN chemosensitive neurons in urethane-anesthetized rats, again independent of CO2 levels. In these animals, isoflurane transiently enhanced activity of the respiratory system, an effect that was most prominent at low levels of respiratory drive and mediated largely by an increase in respiratory frequency. These data indicate that inhalational anesthetics cause activation of RTN neurons, which serve an important integrative role in respiratory control; the increased drive provided by enhanced RTN neuronal activity may contribute, in part, to maintaining respiratory motor activity under immobilizing anesthetic conditions. PMID:20610767

  18. Respiratory syncytial virus activity and climate parameters during a 12-year period.

    PubMed

    Sirimi, Natalia; Miligkos, Michael; Koutouzi, Foteini; Petridou, Evi; Siahanidou, Tania; Michos, Athanasios

    2016-06-01

    The epidemic pattern of respiratory syncytial virus (RSV) infection during long periods and the factors that determine seasonality are not well studied. In order to correlate the RSV epidemic activity with climate parameters, we conducted a retrospective study of children (0-14 year) who were hospitalized because of respiratory tract infection and had an RSV test performed in the major tertiary pediatric hospital of Greece during a 12-year period (2002-2013). Daily data regarding temperature and humidity were obtained from the Hellenic National Meteorological Service. A total of 2030/7516 (27%) children were tested positive for RSV infection. Among RSV positive children 1945/2030 (95.8%) were infants <1 year. A peak of RSV activity was measured in years 2002, 2003, and 2006 (>35% positive). The RSV season in our area spanned from December to April, with higher incidence during January through March. The peak monthly RSV incidence was observed during February with mean temperature 10.34 °C and mean relative humidity 69.16%. Regarding climate conditions, a statistically significant positive correlation was found between monthly RSV activity and mean monthly relative humidity (rho = 0.66, P-value = 0.02), whereas a negative correlation was found with mean monthly temperature (rho = -0.81, P-value = 0.002). However, in the multivariable analysis, only the effect of mean monthly temperature remained statistically significant (IRR = 0.72, 95% CI: 0.68, 0.80). Further understanding of RSV seasonality in different geographic areas would be important in order to timely implement preventing strategies with immunoprophylaxis or future RSV vaccines.

  19. Respiratory System

    MedlinePlus

    ... this page from the NHLBI on Twitter. The Respiratory System The respiratory system is made up of organs ... vessels, and the muscles that enable breathing. The Respiratory System Figure A shows the location of the respiratory ...

  20. Water extract of Pueraria lobata Ohwi has anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines.

    PubMed

    Lin, Tzeng-Jih; Yeh, Chia-Feng; Wang, Kuo-Chih; Chiang, Lien-Chai; Tsai, Jih-Jin; Chang, Jung-San

    2013-12-01

    Human respiratory syncytial virus (HRSV) infects all age groups and causes bronchiolitis, pneumonia, and acute respiratory distress syndrome with a significant mortality rate. To date, only ribavirin has been used to manage HRSV infection. However, ribavirin is expensive with an only modest effect. Furthermore, ribavirin has several side effects, which means it has limited clinical benefit. Pueraria lobata Ohwi (P. lobata) is a common ingredient of Ge-Gen-Tang (Kakkon-to) and Sheng-Ma-Ge-Gen-Tang (Shoma-kakkon-to), which are prescriptions of Chinese traditional medicine proven to have antiviral activity against HRSV. Therefore, it was hypothesized that P. lobata might be effective against HRSV. To find a cost-effective therapeutic modality, both human upper (HEp-2) and lower (A549) respiratory tract cell lines were used to test the hypothesis that P. lobata could inhibit HRSV-induced plaque formation. Results showed that the water extract of P. lobata was effective (p < 0.0001) against HRSV-induced plaque formation. P. lobata was more effective when given prior to viral inoculation (p < 0.0001) by inhibiting viral attachment (p < 0.0001) and penetration (p < 0.0001). However, supplementation with P. lobata could not stimulate interferon secretion after HRSV infection. In conclusion, P. lobata has antiviral activity against HRSV-induced plaque formation in airway mucosa mainly by inhibiting viral attachment and internalization. Further identification of effective constituents could contribute to the prevention of HRSV infection.

  1. The Respiratory Burst and Electrolyte Leakage Induced by Sulfhydryl Blockers in Egeria densa Leaves Are Associated with H2O2 Production and Are Dependent on Ca2+ Influx1

    PubMed Central

    Marrè, Maria Teresa; Amicucci, Enrica; Zingarelli, Luisa; Albergoni, Francesco; Marrè, Erasmo

    1998-01-01

    In leaves of Egeria densa Planchon, N-ethylmaleimide (NEM) and other sulfhydryl-binding reagents induce a temporary increase in nonmitochondrial respiration (ΔQO2) that is inhibited by diphenylene iodonium and quinacrine, two known inhibitors of the plasma membrane NADPH oxidase, and are associated with a relevant increase in electrolyte leakage (M. Bellando, S. Sacco, F. Albergoni, P. Rocco, M.T. Marré [1997] Bot Acta 110: 388–394). In this paper we report data indicating further analogies between the oxidative burst induced by sulfhydryl blockers in E. densa and that induced by pathogen-derived elicitors in animal and plant cells: (a) NEM- and Ag+-induced ΔQO2 was associated with H2O2 production and both effects depended on the presence of external Ca2+; (b) Ca2+ influx was markedly increased by treatment with NEM; (c) the Ca2+ channel blocker LaCl3 inhibited ΔQO2, electrolyte release, and membrane depolarization induced by the sulfhydryl reagents; and (d) LaCl3 also inhibited electrolyte leakage induced by the direct infiltration of the leaves with H2O2. These results suggest a model in which the interaction of sulfhydryl blockers with sulfhydryl groups of cell components would primarily induce an increase in the Ca2+ cytosolic concentration, followed by membrane depolarization and activation of a plasma membrane NADPH oxidase. This latter effect, producing active oxygen species, might further influence plasma membrane permeability, leading to the massive release of electrolytes from the tissue. PMID:9847112

  2. The respiratory burst and electrolyte leakage induced by sulfhydryl blockers in egeria densa leaves are associated with H2O2 production and are dependent on Ca2+ influx

    PubMed

    Marre; Amicucci; Zingarelli; Albergoni; Marre

    1998-12-01

    In leaves of Egeria densa Planchon, N-ethylmaleimide (NEM) and other sulfhydryl-binding reagents induce a temporary increase in nonmitochondrial respiration (DeltaQO2) that is inhibited by diphenylene iodonium and quinacrine, two known inhibitors of the plasma membrane NADPH oxidase, and are associated with a relevant increase in electrolyte leakage (M. Bellando, S. Sacco, F. Albergoni, P. Rocco, M.T. Marre [1997] Bot Acta 110: 388-394). In this paper we report data indicating further analogies between the oxidative burst induced by sulfhydryl blockers in E. densa and that induced by pathogen-derived elicitors in animal and plant cells: (a) NEM- and Ag+-induced DeltaQO2 was associated with H2O2 production and both effects depended on the presence of external Ca2+; (b) Ca2+ influx was markedly increased by treatment with NEM; (c) the Ca2+ channel blocker LaCl3 inhibited DeltaQO2, electrolyte release, and membrane depolarization induced by the sulfhydryl reagents; and (d) LaCl3 also inhibited electrolyte leakage induced by the direct infiltration of the leaves with H2O2. These results suggest a model in which the interaction of sulfhydryl blockers with sulfhydryl groups of cell components would primarily induce an increase in the Ca2+ cytosolic concentration, followed by membrane depolarization and activation of a plasma membrane NADPH oxidase. This latter effect, producing active oxygen species, might further influence plasma membrane permeability, leading to the massive release of electrolytes from the tissue.

  3. Burst suppression probability algorithms: state-space methods for tracking EEG burst suppression

    NASA Astrophysics Data System (ADS)

    Chemali, Jessica; Ching, ShiNung; Purdon, Patrick L.; Solt, Ken; Brown, Emery N.

    2013-10-01

    Objective. Burst suppression is an electroencephalogram pattern in which bursts of electrical activity alternate with an isoelectric state. This pattern is commonly seen in states of severely reduced brain activity such as profound general anesthesia, anoxic brain injuries, hypothermia and certain developmental disorders. Devising accurate, reliable ways to quantify burst suppression is an important clinical and research problem. Although thresholding and segmentation algorithms readily identify burst suppression periods, analysis algorithms require long intervals of data to characterize burst suppression at a given time and provide no framework for statistical inference. Approach. We introduce the concept of the burst suppression probability (BSP) to define the brain's instantaneous propensity of being in the suppressed state. To conduct dynamic analyses of burst suppression we propose a state-space model in which the observation process is a binomial model and the state equation is a Gaussian random walk. We estimate the model using an approximate expectation maximization algorithm and illustrate its application in the analysis of rodent burst suppression recordings under general anesthesia and a patient during induction of controlled hypothermia. Main result. The BSP algorithms track burst suppression on a second-to-second time scale, and make possible formal statistical comparisons of burst suppression at different times. Significance. The state-space approach suggests a principled and informative way to analyze burst suppression that can be used to monitor, and eventually to control, the brain states of patients in the operating room and in the intensive care unit.

  4. Heterogeneity in the properties of burst-forming units of erythroid lineage in sickle cell anemia: DNA synthesis and burst-promoting activity production is related to peripheral hemoglobin F levels

    SciTech Connect

    Croizat, H.; Billett, H.H.; Nagel, R.L. )

    1990-02-15

    Circulating 14-day erythroid progenitors (BFU-E) from 28 sickle cell anemia (SS) patients with hemoglobin F (HbF) levels ranging from 2% to 16% were studied to determine their sensitivity to ({sup 3}H) thymidine kill and burst-promoting activity (BPA)-like factor production. We find that the proportion of BFU-E sensitive to 3H-dT kill, and hence active in DNA synthesis, was inversely correlated with the percent of peripheral HbF when light density (LD) mononuclear cells were used for plating. Regression analysis showed that the correlation between HbF level and BFU-E kill was highly significant (r = .88; P less than .00003). We confirmed the BPA-like factor(s) production by LD mononuclear cells of SS patients, and found, in addition, that this phenomenon is restricted to the population of SS patients with HbF levels lower than 9%. Circulating BFU-E of patients with high HbF levels are not sensitive to 3H-dT, and their mononuclear cells do not release BPA-like factor. In summary, SS patients exhibit differences in the capacity of their mononuclear cells to produce BPA activity according to their peripheral HbF level, as well as to the DNA synthesis-state of their circulating BFU-E. We conclude that erythroid progenitors differ among SS patients in relation to their peripheral HbF level.

  5. Respiratory syncytial virus M2-1 protein induces the activation of nuclear factor kappa B

    SciTech Connect

    Reimers, Kerstin . E-mail: reimers.kerstin@mh-hannover.de; Buchholz, Katja; Werchau, Hermann

    2005-01-20

    Respiratory syncytial virus (RSV) induces the production of a number of cytokines and chemokines by activation of nuclear factor kappa B (NF-{kappa}B). The activation of NF-{kappa}B has been shown to depend on viral replication in the infected cells. In this study, we demonstrate that expression of RSV M2-1 protein, a transcriptional processivity and anti-termination factor, is sufficient to activate NF-{kappa}B in A549 cells. Electromobility shift assays show increased NF-{kappa}B complexes in the nuclei of M2-1-expressing cells. M2-1 protein is found in nuclei of M2-1-expressing cells and in RSV-infected cells. Co-immunoprecipitations of nuclear extracts of M2-1-expressing cells and of RSV-infected cells revealed an association of M2-1 with Rel A protein. Furthermore, the activation of NF-{kappa}B depends on the C-terminus of the RSV M2-1 protein, as shown by NF-{kappa}B-induced gene expression of a reporter gene construct.

  6. Severe acute respiratory syndrome coronavirus E protein transports calcium ions and activates the NLRP3 inflammasome.

    PubMed

    Nieto-Torres, Jose L; Verdiá-Báguena, Carmina; Jimenez-Guardeño, Jose M; Regla-Nava, Jose A; Castaño-Rodriguez, Carlos; Fernandez-Delgado, Raul; Torres, Jaume; Aguilella, Vicente M; Enjuanes, Luis

    2015-11-01

    Severe acute respiratory syndrome coronavirus (SARS-CoV) envelope (E) protein is a viroporin involved in virulence. E protein ion channel (IC) activity is specifically correlated with enhanced pulmonary damage, edema accumulation and death. IL-1β driven proinflammation is associated with those pathological signatures, however its link to IC activity remains unknown. In this report, we demonstrate that SARS-CoV E protein forms protein-lipid channels in ERGIC/Golgi membranes that are permeable to calcium ions, a highly relevant feature never reported before. Calcium ions together with pH modulated E protein pore charge and selectivity. Interestingly, E protein IC activity boosted the activation of the NLRP3 inflammasome, leading to IL-1β overproduction. Calcium transport through the E protein IC was the main trigger of this process. These findings strikingly link SARS-CoV E protein IC induced ionic disturbances at the cell level to immunopathological consequences and disease worsening in the infected organism.

  7. Transcriptional burst frequency and burst size are equally modulated across the human genome

    PubMed Central

    Dar, Roy D.; Razooky, Brandon S.; Singh, Abhyudai; Trimeloni, Thomas V.; McCollum, James M.; Cox, Chris D.; Simpson, Michael L.; Weinberger, Leor S.

    2012-01-01

    Gene expression occurs either as an episodic process, characterized by pulsatile bursts, or as a constitutive process, characterized by a Poisson-like accumulation of gene products. It is not clear which mode of gene expression (constitutive versus bursty) predominates across a genome or how transcriptional dynamics are influenced by genomic position and promoter sequence. Here, we use time-lapse fluorescence microscopy to analyze 8,000 individual human genomic loci and find that at virtually all loci, episodic bursting—as opposed to constitutive expression—is the predominant mode of expression. Quantitative analysis of the expression dynamics at these 8,000 loci indicates that both the frequency and size of the transcriptional bursts varies equally across the human genome, independent of promoter sequence. Strikingly, weaker expression loci modulate burst frequency to increase activity, whereas stronger expression loci modulate burst size to increase activity. Transcriptional activators such as trichostatin A (TSA) and tumor necrosis factor α (TNF) only modulate burst size and frequency along a constrained trend line governed by the promoter. In summary, transcriptional bursting dominates across the human genome, both burst frequency and burst size vary by chromosomal location, and transcriptional activators alter burst frequency and burst size, depending on the expression level of the locus. PMID:23064634

  8. [Cardiac, respiratory, and motor activity in norm and after activation of catecholaminergic systems in newborn rat pups].

    PubMed

    Kuznetsov, S V; Dmitrieva, L E; Sizonov, V A

    2012-01-01

    Study of parameters of the cardiac, respiratory, and motor activity (MA) was carried out on newborn rat pups for the first day after birth (P0) and at the 14th day of postnatal development (P14) after change of the level of activity of catecholaminergic systems. The animals were administered with L-DOPA (25-100 mg/kg) and the indirect adrenomimetic isoamine (3 and 10 mg/kg). Additionally there were studied effects of L-DOPA and isoamine after blockade of D1 and D2 dopamine receptors (antagonists SCH-23390 and sulpiride). The L-DOPA administration produced a dose-dependent MA enhancement with its possible transition into the uninterrupted activity. In P0 the release of monoamines was accompanied by development of weak bradycardia. There was noted a tendency for acceleration of respiration at administration of the low dose both of L-DOPA and of isoamine and for its retardation at high doses. In P14 the L-DOPA administration was accompanied by retardation of the heart rate (HR) by 8 % and by acceleration of respiratory rate by 26%. The isoamine administration produced an insignificant decrease of HR and an increase of respiratory rate (RR) by 8% at the low dose and by 21% at the high dose of the agent. At the blockade of D1 receptors, RR remained close to the background values, while at the blockade of D2 - decreased insignificantly. Blockade of D1 and D2 receptors did not cause significant HR changes. Analysis of the HR variability has shown that both after L-DOPA administration and at blockade of dopamine receptors no unidirectional reaction was observed: in 80 % of rat pups the portion of nerve mechanisms of HR regulation increased, while in the rest--of sympathetic and humoral factors at a decrease of parasympathetic effects. In all rat pups the isoamine administration was accompanied by a shift of the specter power into the higher frequency area; in 60% of animals there were enhanced sympathetic influences. In P14 in rat pups after administration both of L

  9. [Thermoregulatory activity of the intercostal muscles under a hypercapnic load].

    PubMed

    Burachevskaia, L E

    1983-02-01

    In experiments on anesthetized cats, the reactions elicited by CO2 inhalation were studied in single motor units of the intercostal muscles activated during shivering. The excitation of the bulbar respiratory center during shivering was found to modify the activity of the respiratory and tonic motor units. Most of the respiratory motor units in a hypercapnic state increased the mean firing rate by 1.5/sec. The tonic motor units both diminished the mean firing rate and changed the pattern of activity: they began to produce bursts of spikes synchronous with the respiratory rhythm. The problems of supraspinal regulation of activity of the intercostal muscles motoneuron pool are discussed.

  10. Activity against multidrug-resistant Mycobacterium tuberculosis in Mexican plants used to treat respiratory diseases.

    PubMed

    Jimenez-Arellanes, Adelina; Meckes, Mariana; Ramirez, Raquel; Torres, Javier; Luna-Herrera, Julieta

    2003-09-01

    The increase of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) demands the search for alternative antimycobacterial drugs. The aim of this study was to evaluate plants used in Mexican traditional medicine to treat respiratory diseases for activity against MDR-TB. A group of 22 plants was screened for activity against Mycobacterium tuberculosis H37Rv and Mycobacterium avium at concentrations from 50 to 200 microg/mL. The antimycobacterial effect was determined by a microcolorimetric assay with Alamar blue dye. None of the aqueous extracts had antimycobacterial activity. Hexane extracts from Artemisia ludoviciana, Chamaedora tepejilote, Lantana hispida, Juniperus communis and Malva parviflora, and methanol extracts from Artemisia ludoviciana and Juniperus communis inhibited the growth of Mycobacterium tuberculosis. Mycobacterium avium was inhibited by Juniperus communis hexane extract and by Malva parviflora methanol extract. The active extracts were tested against monoresistant variants of Mycobacterium tuberculosis H37Rv (isoniazid, rifampin, streptomycin and ethambutol resistant) and the hexane extract of Lantana hispida showed the best activity. Lantana hispida hexane extract was also active against a group of MDR-TB clinical isolates. In contrast, it did not inhibit the growth of non-tuberculous mycobacteria. The hexane extract of Lantana hispida was fractionated by column chromatography and one of its fractions (FVI) inhibited the growth of all the MDR-TB clinical isolates at concentrations up to 25 microg/mL. This study supports the fact that selecting plants by ethnobotanical criteria enhances the probability of finding species with activity against mycobacteria, and our results point to Lantana hispida as an important source of potential compounds against MDR-TB.

  11. Fiber bragg grating sensor based device for simultaneous measurement of respiratory and cardiac activities.

    PubMed

    Chethana, K; Guru Prasad, A S; Omkar, S N; Asokan, S

    2017-02-01

    This paper reports a novel optical ballistocardiography technique, which is non-invasive, for the simultaneous measurement of cardiac and respiratory activities using a Fiber Bragg Grating Heart Beat Device (FBGHBD). The unique design of FBGHBD offers additional capabilities such as monitoring nascent morphology of cardiac and breathing activity, heart rate variability, heart beat rhythm, etc., which can assist in early clinical diagnosis of many conditions associated with heart and lung malfunctioning. The results obtained from the FBGHBD positioned around the pulmonic area on the chest have been evaluated against an electronic stethoscope which detects and records sound pulses originated from the cardiac activity. In order to evaluate the performance of the FBGHBD, quantitative and qualitative studies have been carried out and the results are found to be reliable and accurate, validating its potential as a standalone medical diagnostic device. The developed FBGHBD is simple in design, robust, portable, EMI proof, shock proof and non-electric in its operation which are desired features for any clinical diagnostic tool used in hospital environment.

  12. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people.

    PubMed

    Jung, Ju-Hyeon; Kim, Nan-Soo

    2016-03-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were collected from the right-side diaphragm, external intercostal, and sternocleidomastoid, and pulmonary functions (forced expiratory volume in 1 s, forced vital capacity, and their ratio; peak expiratory flow; and maximal inspiratory pressure) were measured. [Results] Comparison of the relative activity of the diaphragm showed significant differences between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. Furthermore, significant differences were found in sternocleidomastoid relative activity between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. [Conclusion] During inspiratory muscle training in the clinic, the patients were assisted (verbally or through feedback) by therapists to avoid overactivation of their accessory muscles (sternocleidomastoid). This study recommends that inspiratory muscle training be performed at an accurate and appropriate intensity through the practice of proper deep breathing.

  13. Prevention of adult respiratory distress syndrome with plasminogen activator in pigs.

    PubMed

    Hardaway, R M; Williams, C H; Marvasti, M; Farias, M; Tseng, A; Pinon, I; Yanez, D; Martinez, M; Navar, J

    1990-12-01

    Death from traumatic shock has been associated with loss of blood externally or internally. However, many patients die after trauma, even though blood volume restoration is adequate. Death is often due to pulmonary failure (adult respiratory distress syndrome [ARDS]). Death and ARDS have been associated with disseminated intravascular coagulation (DIC) and microclots in the lungs. Dissolution of the microclots after trauma can be achieved by activation of endogenous plasmin. Nine pigs were anesthetized for 48 h. Trauma was administered by 60 standard blows to each thigh resulting in a bruise of muscle but no skin, bone, or major vessel injury. Nutrition and respiration were maintained at normal levels. All nine pigs died with severe lung pathology and low PaO2. Ten other traumatized pigs were treated with a plasminogen activator iv 4 h after trauma. Five of these were treated with tissue plasminogen activator (tPA) and five with urokinase. All treated pigs survived 48 h and maintained a normal PaO2. Autopsy showed minimal lung pathology.

  14. Nighttime instabilities of neurophysiological, cardiovascular, and respiratory activity: integrative modeling and preliminary results

    PubMed Central

    Shusterman, Vladimir; Troy, William C.; Abdelmessih, Medhat; Hoffman, Stacy; Nemec, Jan; Strollo, Patrick J.; London, Barry; Lampert, Rachel

    2015-01-01

    Unstable (cyclical alternating pattern, or CAP) sleep is associated with surges of sympathetic nervous system activity, increased blood pressure and vasoconstriction, heightened baroreflex sensitivity, and unstable heart rhythm and breathing. In susceptible persons, CAP sleep provokes clinically significant events, including hypertensive crises, sleep-disordered breathing, and cardiac arrhythmias. Here we explore the neurophysiology of CAP sleep and its impact on cardiovascular and respiratory functions. We show that: (i) an increase in neurophysiological recovery rate can explain the emergence of slow, self-sustained, hypersynchronized A1 CAP-sleep pattern and its transition to the faster A2-A3 CAP-sleep patterns; (ii) in a two-dimensional, continuous model of cardiac tissue with heterogeneous action potential duration (APD) distribution, heart rate accelerations during CAP sleep may encounter incompletely recovered electrical excitability in cell clusters with longer APD. If the interaction between short cycle length and incomplete, spatially heterogeneous repolarization persists over multiple cycles, irregularities and asymmetry of depolarization front may accumulate and ultimately lead to a conduction block, retrograde conduction, breakup of activation waves, reentrant activity, and arrhythmias; and (iii) these modeling results are consistent with the nighttime data obtained from patients with structural heart disease (N=13) that show clusters of atrial and ventricular premature beats occurring during the periods of unstable heart rhythm and respiration that accompany CAP sleep. In these patients, CAP sleep is also accompanied by delayed adaptation of QT intervals and T-wave alternans. PMID:26341647

  15. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people

    PubMed Central

    Jung, Ju-hyeon; Kim, Nan-soo

    2016-01-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were collected from the right-side diaphragm, external intercostal, and sternocleidomastoid, and pulmonary functions (forced expiratory volume in 1 s, forced vital capacity, and their ratio; peak expiratory flow; and maximal inspiratory pressure) were measured. [Results] Comparison of the relative activity of the diaphragm showed significant differences between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. Furthermore, significant differences were found in sternocleidomastoid relative activity between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. [Conclusion] During inspiratory muscle training in the clinic, the patients were assisted (verbally or through feedback) by therapists to avoid overactivation of their accessory muscles (sternocleidomastoid). This study recommends that inspiratory muscle training be performed at an accurate and appropriate intensity through the practice of proper deep breathing. PMID:27134409

  16. Marker-less reconstruction of dense 4-D surface motion fields using active laser triangulation for respiratory motion management.

    PubMed

    Bauer, Sebastian; Berkels, Benjamin; Ettl, Svenja; Arold, Oliver; Hornegger, Joachim; Rumpf, Martin

    2012-01-01

    To manage respiratory motion in image-guided interventions a novel sparse-to-dense registration approach is presented. We apply an emerging laser-based active triangulation (AT) sensor that delivers sparse but highly accurate 3-D measurements in real-time. These sparse position measurements are registered with a dense reference surface extracted from planning data. Thereby a dense displacement field is reconstructed which describes the 4-D deformation of the complete patient body surface and recovers a multi-dimensional respiratory signal for application in respiratory motion management. The method is validated on real data from an AT prototype and synthetic data sampled from dense surface scans acquired with a structured light scanner. In a study on 16 subjects, the proposed algorithm achieved a mean reconstruction accuracy of +/- 0.22 mm w.r.t. ground truth data.

  17. Anti-viral activity of water extract of Paeonia lactiflora pallas against human respiratory syncytial virus in human respiratory tract cell lines.

    PubMed

    Lin, Tzeng-Jih; Wang, Kuo-Chih; Lin, Chun-Ching; Chiang, Lien-Chai; Chang, Jung-San

    2013-01-01

    Paeonia lactiflora Pallas (P. lactiflora, Ranunculaceae) is a common ingredient of Sheng-Ma-Ge-Gen-Tang (SMGGT; Shoma-kakkon-to) and Ge-Gen-Tang (GGT; kakkon-to). SMGGT and GGT are different prescriptions of traditional Chinese medicine with different ingredients designed for airway symptoms. Both SMGGT and GGT have anti-viral activity against human respiratory syncytial virus (HRSV). Therefore, P. lactiflora was hypothesized to be the effective ingredient of both SMGGT and GGT against HRSV. However, P. lactiflora does not have any proven antiviral activity. This study used both human upper (Human larynx epidermoid carcinoma cell line, HEp-2) and lower (human lung carcinoma cell line, A549) respiratory tract cells to test the hypothesis that a hot water extract of P. lactiflora could effectively inhibit plaque formation induced by HRSV infection. The ability of P. lactiflora to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA). The results showed that P. lactiflora was time-dependently and dose-dependently effective against HRSV in HEp-2 and A549 cells, particularly supplemented before viral inoculation (p < 0.0001). 10 μg/ml P. lactiflora had a comparable anti-HRSV activity with 10 μg/ml ribavirin, a broad-spectrum antiviral agent. P. lactiflora was dose-dependently effective against viral attachment (p < 0.0001), with a better effect on A549 cells (p < 0.0001). P. lactiflora was time-dependently (p < 0.0001) and dose-dependently (p < 0.0001) effective against viral penetration. Moreover, P. lactiflora stimulated IFN-β secretion without any effect on TNF-α secretion. Therefore, P. lactiflora could be beneficial at preventing HRSV infection by inhibiting viral attachment, internalization, and stimulating IFN secretion.

  18. Human serum activity of telithromycin, azithromycin and amoxicillin/clavulanate against common aerobic and anaerobic respiratory pathogens.

    PubMed

    Stein, Gary E; Schooley, Sharon; Tyrrell, Kerin L; Citron, Diane M; Goldstein, Ellie J C

    2007-01-01

    Telithromycin is a new ketolide antimicrobial with a good in vitro activity against both aerobic and anaerobic respiratory pathogens. In this study, we evaluated the antibacterial activity over time of telithromycin (800mg), azithromycin (500mg), and amoxicillin/clavulanate (875/125mg) in serum following single oral doses of these agents to 10 healthy subjects. Inhibitory and bactericidal titers were determined at 2, 6, 12, and 24h after each dose and the median titer was used to determine antibacterial activity. Against two azithromycin-resistant strains of Streptococcus pneumoniae, both telithromycin (MIC=0.25 and 0.5 microg/mL) and amoxicillin/clavulanate exhibited inhibitory and cidal activity for at least 6h. All three antibiotics provided prolonged (>or=12h) inhibitory activity against strains of Hemophilus influenzae (telithromycin MIC=4.0 microg/ml). Both telithromycin and amoxicillin/clavulanate exhibited rapid and prolonged inhibitory activity (>or=12h) against each of the anaerobes studied (Finegoldia [Peptostreptococcus] magna Peptostreptococcus micros, Prevotella bivia, and Prevotella melaninogenica). Moreover, both agents provided bactericidal activity against both Prevotella species. In this ex vivo pharmacodynamic study, we found that telithromycin provided rapid and prolonged antibacterial activity in serum against macrolide-resistant strains of S. pneumoniae, beta-lactamase-positive and -negative strains of H. influenzae, and common respiratory anaerobic pathogens. These findings suggest that telithromycin could have clinical utility in the treatment of community-acquired mixed aerobic-anaerobic respiratory tract infections, including chronic sinusitis and aspiration pneumonia.

  19. A novel preterm respiratory mechanics active simulator to test the performances of neonatal pulmonary ventilators

    NASA Astrophysics Data System (ADS)

    Cappa, Paolo; Sciuto, Salvatore Andrea; Silvestri, Sergio

    2002-06-01

    A patient active simulator is proposed which is capable of reproducing values of the parameters of pulmonary mechanics of healthy newborns and preterm pathological infants. The implemented prototype is able to: (a) let the operator choose the respiratory pattern, times of apnea, episodes of cough, sobs, etc., (b) continuously regulate and control the parameters characterizing the pulmonary system; and, finally, (c) reproduce the attempt of breathing of a preterm infant. Taking into account both the limitation due to the chosen application field and the preliminary autocalibration phase automatically carried out by the proposed device, accuracy and reliability on the order of 1% is estimated. The previously indicated value has to be considered satisfactory in light of the field of application and the small values of the simulated parameters. Finally, the achieved metrological characteristics allow the described neonatal simulator to be adopted as a reference device to test performances of neonatal ventilators and, more specifically, to measure the time elapsed between the occurrence of a potentially dangerous condition to the patient and the activation of the corresponding alarm of the tested ventilator.

  20. Redox-induced activation of the proton pump in the respiratory complex I

    PubMed Central

    Sharma, Vivek; Belevich, Galina; Gamiz-Hernandez, Ana P.; Róg, Tomasz; Vattulainen, Ilpo; Verkhovskaya, Marina L.; Wikström, Mårten; Hummer, Gerhard; Kaila, Ville R. I.

    2015-01-01

    Complex I functions as a redox-linked proton pump in the respiratory chains of mitochondria and bacteria, driven by the reduction of quinone (Q) by NADH. Remarkably, the distance between the Q reduction site and the most distant proton channels extends nearly 200 Å. To elucidate the molecular origin of this long-range coupling, we apply a combination of large-scale molecular simulations and a site-directed mutagenesis experiment of a key residue. In hybrid quantum mechanics/molecular mechanics simulations, we observe that reduction of Q is coupled to its local protonation by the His-38/Asp-139 ion pair and Tyr-87 of subunit Nqo4. Atomistic classical molecular dynamics simulations further suggest that formation of quinol (QH2) triggers rapid dissociation of the anionic Asp-139 toward the membrane domain that couples to conformational changes in a network of conserved charged residues. Site-directed mutagenesis data confirm the importance of Asp-139; upon mutation to asparagine the Q reductase activity is inhibited by 75%. The current results, together with earlier biochemical data, suggest that the proton pumping in complex I is activated by a unique combination of electrostatic and conformational transitions. PMID:26330610

  1. Redox-induced activation of the proton pump in the respiratory complex I.

    PubMed

    Sharma, Vivek; Belevich, Galina; Gamiz-Hernandez, Ana P; Róg, Tomasz; Vattulainen, Ilpo; Verkhovskaya, Marina L; Wikström, Mårten; Hummer, Gerhard; Kaila, Ville R I

    2015-09-15

    Complex I functions as a redox-linked proton pump in the respiratory chains of mitochondria and bacteria, driven by the reduction of quinone (Q) by NADH. Remarkably, the distance between the Q reduction site and the most distant proton channels extends nearly 200 Å. To elucidate the molecular origin of this long-range coupling, we apply a combination of large-scale molecular simulations and a site-directed mutagenesis experiment of a key residue. In hybrid quantum mechanics/molecular mechanics simulations, we observe that reduction of Q is coupled to its local protonation by the His-38/Asp-139 ion pair and Tyr-87 of subunit Nqo4. Atomistic classical molecular dynamics simulations further suggest that formation of quinol (QH2) triggers rapid dissociation of the anionic Asp-139 toward the membrane domain that couples to conformational changes in a network of conserved charged residues. Site-directed mutagenesis data confirm the importance of Asp-139; upon mutation to asparagine the Q reductase activity is inhibited by 75%. The current results, together with earlier biochemical data, suggest that the proton pumping in complex I is activated by a unique combination of electrostatic and conformational transitions.

  2. Bursts in discontinuous Aeolian saltation

    PubMed Central

    Carneiro, M. V.; Rasmussen, K. R.; Herrmann, H. J.

    2015-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of discontinuous flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the fluid threshold Shields number θc. The time delay between each burst decreases on average with the increase of the Shields number until sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain discontinuous flux even below the fluid threshold. PMID:26073305

  3. A self-adapting approach for the detection of bursts and network bursts in neuronal cultures.

    PubMed

    Pasquale, Valentina; Martinoia, Sergio; Chiappalone, Michela

    2010-08-01

    Dissociated networks of neurons typically exhibit bursting behavior, whose features are strongly influenced by the age of the culture, by chemical/electrical stimulation or by environmental conditions. To help the experimenter in identifying the changes possibly induced by specific protocols, we developed a self-adapting method for detecting both bursts and network bursts from electrophysiological activity recorded by means of micro-electrode arrays. The algorithm is based on the computation of the logarithmic inter-spike interval histogram and automatically detects the best threshold to distinguish between inter- and intra-burst inter-spike intervals for each recording channel of the array. An analogous procedure is followed for the detection of network bursts, looking for sequences of closely spaced single-channel bursts. We tested our algorithm on recordings of spontaneous as well as chemically stimulated activity, comparing its performance to other methods available in the literature.

  4. Analysis of Family Structures Reveals Robustness or Sensitivity of Bursting Activity to Parameter Variations in a Half-Center Oscillator (HCO) Model

    PubMed Central

    2016-01-01

    The underlying mechanisms that support robustness in neuronal networks are as yet unknown. However, recent studies provide evidence that neuronal networks are robust to natural variations, modulation, and environmental perturbations of parameters, such as maximal conductances of intrinsic membrane and synaptic currents. Here we sought a method for assessing robustness, which might easily be applied to large brute-force databases of model instances. Starting with groups of instances with appropriate activity (e.g., tonic spiking), our method classifies instances into much smaller subgroups, called families, in which all members vary only by the one parameter that defines the family. By analyzing the structures of families, we developed measures of robustness for activity type. Then, we applied these measures to our previously developed model database, HCO-db, of a two-neuron half-center oscillator (HCO), a neuronal microcircuit from the leech heartbeat central pattern generator where the appropriate activity type is alternating bursting. In HCO-db, the maximal conductances of five intrinsic and two synaptic currents were varied over eight values (leak reversal potential also varied, five values). We focused on how variations of particular conductance parameters maintain normal alternating bursting activity while still allowing for functional modulation of period and spike frequency. We explored the trade-off between robustness of activity type and desirable change in activity characteristics when intrinsic conductances are altered and identified the hyperpolarization-activated (h) current as an ideal target for modulation. We also identified ensembles of model instances that closely approximate physiological activity and can be used in future modeling studies. PMID:27595135

  5. Respiratory Syncytial Virus Inhibitor AZ-27 Differentially Inhibits Different Polymerase Activities at the Promoter

    PubMed Central

    Noton, Sarah L.; Nagendra, Kartikeya; Dunn, Ewan F.; Mawhorter, Michael E.; Yu, Qin

    2015-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is the leading cause of pediatric respiratory disease. RSV has an RNA-dependent RNA polymerase that transcribes and replicates the viral negative-sense RNA genome. The large polymerase subunit (L) has multiple enzymatic activities, having the capability to synthesize RNA and add and methylate a cap on each of the viral mRNAs. Previous studies (H. Xiong et al., Bioorg Med Chem Lett, 23:6789–6793, 2013, http://dx.doi.org/10.1016/j.bmcl.2013.10.018; C. L. Tiong-Yip et al., Antimicrob Agents Chemother, 58:3867–3873, 2014, http://dx.doi.org/10.1128/AAC.02540-14) had identified a small-molecule inhibitor, AZ-27, that targets the L protein. In this study, we examined the effect of AZ-27 on different aspects of RSV polymerase activity. AZ-27 was found to inhibit equally both mRNA transcription and genome replication in cell-based minigenome assays, indicating that it inhibits a step common to both of these RNA synthesis processes. Analysis in an in vitro transcription run-on assay, containing RSV nucleocapsids, showed that AZ-27 inhibits synthesis of transcripts from the 3′ end of the genome to a greater extent than those from the 5′ end, indicating that it inhibits transcription initiation. Consistent with this finding, experiments that assayed polymerase activity on the promoter showed that AZ-27 inhibited transcription and replication initiation. The RSV polymerase also can utilize the promoter sequence to perform a back-priming reaction. Interestingly, addition of AZ-27 had no effect on the addition of up to three nucleotides by back-priming but inhibited further extension of the back-primed RNA. These data provide new information regarding the mechanism of inhibition by AZ-27. They also suggest that the RSV polymerase adopts different conformations to perform its different activities at the promoter. IMPORTANCE Currently, there are no effective antiviral drugs to treat RSV infection. The RSV polymerase is an

  6. Burst-by-burst laser frequency monitor

    NASA Technical Reports Server (NTRS)

    Esproles, Carlos (Inventor)

    1994-01-01

    The invention is a system for real-time frequency monitoring and display of an RF burst where the burst frequency is analyzed and displayed on a burst-by-burst basis in order to allow for frequency control. Although the invention was made for monitoring the laser frequency of a LIDAR system, it has other applications where realtime monitoring is required. The novelty of the invention resides in the use of a counter that is reset at the beginning of each unit time of monitoring and then gated for a unit of time. The invention also has an LED bar graph for displaying the measure of frequency at the end of each unit time in either a bar length mode or a moving dot mode. In the latter mode, the operator makes necessary adjustments to maintain the dot at the center of the bar graph.

  7. Coordinated Respiratory Motor Activity in Nerves Innervating the Upper Airway Muscles in Rats.

    PubMed

    Tachikawa, Satoshi; Nakayama, Kiyomi; Nakamura, Shiro; Mochizuki, Ayako; Iijima, Takehiko; Inoue, Tomio

    2016-01-01

    Maintaining the patency of the upper airway during breathing is of vital importance. The activity of various muscles is related to the patency of the upper airway. In the present study, we examined the respiratory motor activity in the efferent nerves innervating the upper airway muscles to determine the movements of the upper airway during respiration under normocapnic conditions (pH = 7.4) and in hypercapnic acidosis (pH = 7.2). Experiments were performed on arterially perfused decerebrate rats aged between postnatal days 21-35. We recorded the efferent nerve activity in a branch of the cervical spinal nerve innervating the infrahyoid muscles (CN), the hypoglossal nerve (HGN), the external branch of the superior laryngeal nerve (SLN), and the recurrent laryngeal nerve (RLN) with the phrenic nerve (PN). Inspiratory nerve discharges were observed in all these nerves under normocapnic conditions. The onset of inspiratory discharges in the CN and HGN was slightly prior to those in the SLN and RLN. When the CO2 concentration in the perfusate was increased from 5% to 8% to prepare for hypercapnic acidosis, the peak amplitudes of the inspiratory discharges in all the recorded nerves were increased. Moreover, hypercapnic acidosis induced pre-inspiratory discharges in the CN, HGN, SLN, and RLN. The onset of pre-inspiratory discharges in the CN, HGN, and SLN was prior to that of discharges in the RLN. These results suggest that the securing of the airway that occurs a certain time before dilation of the glottis may facilitate ventilation and improve hypercapnic acidosis.

  8. Coordinated Respiratory Motor Activity in Nerves Innervating the Upper Airway Muscles in Rats

    PubMed Central

    Tachikawa, Satoshi; Nakayama, Kiyomi; Nakamura, Shiro; Mochizuki, Ayako; Iijima, Takehiko; Inoue, Tomio

    2016-01-01

    Maintaining the patency of the upper airway during breathing is of vital importance. The activity of various muscles is related to the patency of the upper airway. In the present study, we examined the respiratory motor activity in the efferent nerves innervating the upper airway muscles to determine the movements of the upper airway during respiration under normocapnic conditions (pH = 7.4) and in hypercapnic acidosis (pH = 7.2). Experiments were performed on arterially perfused decerebrate rats aged between postnatal days 21–35. We recorded the efferent nerve activity in a branch of the cervical spinal nerve innervating the infrahyoid muscles (CN), the hypoglossal nerve (HGN), the external branch of the superior laryngeal nerve (SLN), and the recurrent laryngeal nerve (RLN) with the phrenic nerve (PN). Inspiratory nerve discharges were observed in all these nerves under normocapnic conditions. The onset of inspiratory discharges in the CN and HGN was slightly prior to those in the SLN and RLN. When the CO2 concentration in the perfusate was increased from 5% to 8% to prepare for hypercapnic acidosis, the peak amplitudes of the inspiratory discharges in all the recorded nerves were increased. Moreover, hypercapnic acidosis induced pre-inspiratory discharges in the CN, HGN, SLN, and RLN. The onset of pre-inspiratory discharges in the CN, HGN, and SLN was prior to that of discharges in the RLN. These results suggest that the securing of the airway that occurs a certain time before dilation of the glottis may facilitate ventilation and improve hypercapnic acidosis. PMID:27832132

  9. Autaptic Connections Shift Network Excitability and Bursting

    PubMed Central

    Wiles, Laura; Gu, Shi; Pasqualetti, Fabio; Parvesse, Brandon; Gabrieli, David; Bassett, Danielle S.; Meaney, David F.

    2017-01-01

    We examine the role of structural autapses, when a neuron synapses onto itself, in driving network-wide bursting behavior. Using a simple spiking model of neuronal activity, we study how autaptic connections affect activity patterns, and evaluate if controllability significantly affects changes in bursting from autaptic connections. Adding more autaptic connections to excitatory neurons increased the number of spiking events and the number of network-wide bursts. We observed excitatory synapses contributed more to bursting behavior than inhibitory synapses. We evaluated if neurons with high average controllability, predicted to push the network into easily achievable states, affected bursting behavior differently than neurons with high modal controllability, thought to influence the network into difficult to reach states. Results show autaptic connections to excitatory neurons with high average controllability led to higher burst frequencies than adding the same number of self-looping connections to neurons with high modal controllability. The number of autapses required to induce bursting was lowered by adding autapses to high degree excitatory neurons. These results suggest a role of autaptic connections in controlling network-wide bursts in diverse cortical and subcortical regions of mammalian brain. Moreover, they open up new avenues for the study of dynamic neurophysiological correlates of structural controllability. PMID:28266594

  10. Smoke Extracts and Nicotine, but not Tobacco Extracts, Potentiate Firing and Burst Activity of Ventral Tegmental Area Dopaminergic Neurons in Mice

    PubMed Central

    Marti, Fabio; Arib, Ouafa; Morel, Carole; Dufresne, Virginie; Maskos, Uwe; Corringer, Pierre-Jean; de Beaurepaire, Renaud; Faure, Philippe

    2011-01-01

    Nicotine prominently mediates the behavioral effects of tobacco consumption, either through smoking or when taking tobacco by snuff or chew. However, many studies question the exclusive role of nicotine in these effects. The use of preparations containing all the components of tobacco, such as tobacco and smoke extracts, may be more suitable than nicotine alone to investigate the behavioral effects of smoking and tobacco intake. In the present study, the electrophysiological effects of tobacco and smoke on ventral tegmental area dopaminergic (DA) neurons were examined in vivo in anesthetized wild-type (WT), β2-nicotinic acetylcholine receptor (nAChR) knockout (β2−/−), α4−/−, and α6−/− mice and compared with those of nicotine alone. In WT mice, smoke and nicotine had similar potentiating effects on DA cell activity, but the action of tobacco on neuronal firing was weak and often inhibitory. In particular, nicotine triggered strong bursting activity, whereas no bursting activity was observed after tobacco extract (ToE) administration. In β2−/− mice, nicotine or extract elicited no modification of the firing patterns of DA cells, indicating that extract acts predominantly through nAChRs. The differences between DA cell activation profiles induced by tobacco and nicotine alone observed in WT persisted in α6−/− mice but not in α4−/− mice. These results would suggest that tobacco has lower addiction-generating properties compared with either nicotine alone or smoke. The weak activation and prominent inhibition obtained with ToEs suggest that tobacco contains compounds that counteract some of the activating effects of nicotine and promote inhibition on DA cell acting through α4β2*-nAChRs. The nature of these compounds remains to be elucidated. It nevertheless confirms that nicotine is the main substance involved in the tobacco addiction-related activation of mesolimbic DA neurons. PMID:21716264

  11. Knockout of the BK β2 subunit abolishes inactivation of BK currents in mouse adrenal chromaffin cells and results in slow-wave burst activity

    PubMed Central

    Martinez-Espinosa, Pedro L.; Yang, Chengtao; Gonzalez-Perez, Vivian; Xia, Xiao-Ming

    2014-01-01

    Rat and mouse adrenal medullary chromaffin cells (CCs) express an inactivating BK current. This inactivation is thought to arise from the assembly of up to four β2 auxiliary subunits (encoded by the kcnmb2 gene) with a tetramer of pore-forming Slo1 α subunits. Although the physiological consequences of inactivation remain unclear, differences in depolarization-evoked firing among CCs have been proposed to arise from the ability of β2 subunits to shift the range of BK channel activation. To investigate the role of BK channels containing β2 subunits, we generated mice in which the gene encoding β2 was deleted (β2 knockout [KO]). Comparison of proteins from wild-type (WT) and β2 KO mice allowed unambiguous demonstration of the presence of β2 subunit in various tissues and its coassembly with the Slo1 α subunit. We compared current properties and cell firing properties of WT and β2 KO CCs in slices and found that β2 KO abolished inactivation, slowed action potential (AP) repolarization, and, during constant current injection, decreased AP firing. These results support the idea that the β2-mediated shift of the BK channel activation range affects repetitive firing and AP properties. Unexpectedly, CCs from β2 KO mice show an increased tendency toward spontaneous burst firing, suggesting that the particular properties of BK channels in the absence of β2 subunits may predispose to burst firing. PMID:25267913

  12. Knockout of the BK β2 subunit abolishes inactivation of BK currents in mouse adrenal chromaffin cells and results in slow-wave burst activity.

    PubMed

    Martinez-Espinosa, Pedro L; Yang, Chengtao; Gonzalez-Perez, Vivian; Xia, Xiao-Ming; Lingle, Christopher J

    2014-10-01

    Rat and mouse adrenal medullary chromaffin cells (CCs) express an inactivating BK current. This inactivation is thought to arise from the assembly of up to four β2 auxiliary subunits (encoded by the kcnmb2 gene) with a tetramer of pore-forming Slo1 α subunits. Although the physiological consequences of inactivation remain unclear, differences in depolarization-evoked firing among CCs have been proposed to arise from the ability of β2 subunits to shift the range of BK channel activation. To investigate the role of BK channels containing β2 subunits, we generated mice in which the gene encoding β2 was deleted (β2 knockout [KO]). Comparison of proteins from wild-type (WT) and β2 KO mice allowed unambiguous demonstration of the presence of β2 subunit in various tissues and its coassembly with the Slo1 α subunit. We compared current properties and cell firing properties of WT and β2 KO CCs in slices and found that β2 KO abolished inactivation, slowed action potential (AP) repolarization, and, during constant current injection, decreased AP firing. These results support the idea that the β2-mediated shift of the BK channel activation range affects repetitive firing and AP properties. Unexpectedly, CCs from β2 KO mice show an increased tendency toward spontaneous burst firing, suggesting that the particular properties of BK channels in the absence of β2 subunits may predispose to burst firing.

  13. Plasminogen activator inhibitor I 4G/5G polymorphism in neonatal respiratory distress syndrome.

    PubMed

    Armangil, Didem; Yurdakök, Murat; Okur, Hamza; Gürgey, Aytemiz

    2011-08-01

    Fibrin monomers inhibit surfactant function. 4G/5G insertion/deletion polymorphism plays an important role in the regulation of plasminogen activator inhibitor 1 (PAI-1) gene expression. To examine the genotype distribution of PAI-1 polymorphism in 60 infants with respiratory distress syndrome (RDS) and 53 controls, an allele-specific polymerase chain reaction (PCR) was used. The proportion of 4G/4G, 4G/5G, and 5G/5G genotypes did not differ statistically between the RDS and control groups (P > .05). Having PAI-1 4G/4G genotype polymorphism appears to increase the risk of RDS (odds ratio [OR] =1.5; 95% confidence interval [CI], 0.5-4.3), although it was not statistically significant. No relation was found between the PAI-1 4G/5G polymorphisms and RDS, but there was an increased risk associated with the 4G variant of the PAI-1 gene. We believe that our findings of increased 4G allele of the PAI-1 gene in infants with RDS would also help to clarify the pathogenesis of RDS.

  14. Burst and Outburst Characteristics of Magnetar 4U 0142+61

    NASA Astrophysics Data System (ADS)

    Göğüş, Ersin; Lin, Lin; Roberts, Oliver J.; Chakraborty, Manoneeta; Kaneko, Yuki; Gill, Ramandeep; Granot, Jonathan; van der Horst, Alexander J.; Watts, Anna L.; Baring, Matthew; Kouveliotou, Chryssa; Huppenkothen, Daniela; Younes, George

    2017-01-01

    We have compiled the most comprehensive burst sample from magnetar 4U 0142+61, comprising 27 bursts from its three burst-active episodes in 2011, 2012 and the latest one in 2015 observed with Swift/Burst Alert Telescope and Fermi/Gamma-ray Burst Monitor. Bursts from 4U 0142+61 morphologically resemble typical short bursts from other magnetars. However, 4U 0142+61 bursts are less energetic compared to the bulk of magnetar bursts. We uncovered an extended tail emission following a burst on 2015 February 28, with a thermal nature, cooling over a timescale of several minutes. During this tail emission, we also uncovered pulse peak phase aligned X-ray bursts, which could originate from the same underlying mechanism as that of the extended burst tail, or an associated and spatially coincident but different mechanism.

  15. Adsorption characteristics of activated carbon fibers (ACFs) for toluene: application in respiratory protection.

    PubMed

    Balanay, Jo Anne G; Bartolucci, Alfred A; Lungu, Claudiu T

    2014-01-01

    Granular activated carbon (GAC) is currently the standard adsorbent in respirators against several gases and vapors because of its efficiency, low cost, and available technology. However, a drawback of GAC due to its granular form is its need for containment, adding weight and bulkiness to respirators. This makes respirators uncomfortable to wear, resulting in poor compliance in their use. Activated carbon fibers (ACF) are considered viable alternative adsorbent materials for developing thinner, light-weight, and efficient respirators because of their larger surface area, lighter weight, and fabric form. This study aims to determine the critical bed depth and adsorption capacity of different types of commercially available ACFs for toluene to understand how thin a respirator can be and the service life of the adsorbents, respectively. ACF in cloth (ACFC) and felt (ACFF) forms with three different surface areas per form were tested. Each ACF type was challenged with six concentrations of toluene (50, 100, 200, 300, 400, 500 ppm) at constant air temperature (23°C), relative humidity (50%), and airflow (16 LPM) at different adsorbent weights and bed depths. Breakthrough data were obtained for each adsorbent using gas chromatography with flame ionization detector. The ACFs' surface areas were measured by an automatic physisorption analyzer. The results showed that ACFC has a lower critical bed depth and higher adsorption capacity compared to ACFF with similar surface area for each toluene concentration. Among the ACF types, ACFC2000 (cloth with the highest measured surface area of 1614 ± 5 m(2)/g) has one of the lowest critical bed depths (ranging from 0.11-0.22 cm) and has the highest adsorption capacity (ranging from 595-878 mg/g). Based on these studied adsorption characteristics, it is concluded that ACF has great potential for application in respiratory protection against toluene, particularly the ACFC2000, which is the best candidate for developing thinner and

  16. The effect of growth and measurement temperature on the activity of the alternative respiratory pathway

    PubMed

    Gonzalez-Meler; Ribas-Carbo; Giles; Siedow

    1999-07-01

    A postulated role of the CN-resistant alternative respiratory pathway in plants is the maintenance of mitochondrial electron transport at low temperatures that would otherwise inhibit the main phosphorylating pathway and prevent the formation of toxic reactive oxygen species. This role is supported by the observation that alternative oxidase protein levels often increase when plants are subjected to growth at low temperatures. We used oxygen isotope fractionation to measure the distribution of electrons between the main and alternative pathways in mung bean (Vigna radiata) and soybean (Glycine max) following growth at low temperature. The amount of alternative oxidase protein in mung bean grown at 19 degrees C increased over 2-fold in both hypocotyls and leaves compared with plants grown at 28 degrees C but was unchanged in soybean cotyledons grown at 14 degrees C compared with plants grown at 28 degrees C. When the short-term response of tissue respiration was measured over the temperature range of 35 degrees C to 9 degrees C, decreases in the activities of both main and alternative pathway respiration were observed regardless of the growth temperature, and the relative partitioning of electrons to the alternative pathway generally decreased as the temperature was lowered. However, cold-grown mung bean plants that up-regulated the level of alternative oxidase protein maintained a greater electron partitioning to the alternative oxidase when measured at temperatures below 19 degrees C supporting a role for the alternative pathway in response to low temperatures in mung bean. This response was not observed in soybean cotyledons, in which high levels of alternative pathway activity were seen at both high and low temperatures.

  17. Acute Carnosine Administration Increases Respiratory Chain Complexes and Citric Acid Cycle Enzyme Activities in Cerebral Cortex of Young Rats.

    PubMed

    Macedo, Levy W; Cararo, José H; Maravai, Soliany G; Gonçalves, Cinara L; Oliveira, Giovanna M T; Kist, Luiza W; Guerra Martinez, Camila; Kurtenbach, Eleonora; Bogo, Maurício R; Hipkiss, Alan R; Streck, Emilio L; Schuck, Patrícia F; Ferreira, Gustavo C

    2016-10-01

    Carnosine (β-alanyl-L-histidine) is an imidazole dipeptide synthesized in excitable tissues of many animals, whose biochemical properties include carbonyl scavenger, anti-oxidant, bivalent metal ion chelator, proton buffer, and immunomodulating agent, although its precise physiological role(s) in skeletal muscle and brain tissues in vivo remain unclear. The aim of the present study was to investigate the in vivo effects of acute carnosine administration on various aspects of brain bioenergetics of young Wistar rats. The activity of mitochondrial enzymes in cerebral cortex was assessed using a spectrophotometer, and it was found that there was an increase in the activities of complexes I-III and II-III and succinate dehydrogenase in carnosine-treated rats, as compared to vehicle-treated animals. However, quantitative real-time RT-PCR (RT-qPCR) data on mRNA levels of mitochondrial biogenesis-related proteins (nuclear respiratory factor 1 (Nrf1), peroxisome proliferator-activated receptor-γ coactivator 1-α (Ppargc1α), and mitochondrial transcription factor A (Tfam)) were not altered significantly and therefore suggest that short-term carnosine administration does not affect mitochondrial biogenesis. It was in agreement with the finding that immunocontent of respiratory chain complexes was not altered in animals receiving carnosine. These observations indicate that acute carnosine administration increases the respiratory chain and citric acid cycle enzyme activities in cerebral cortex of young rats, substantiating, at least in part, a neuroprotector effect assigned to carnosine against oxidative-driven disorders.

  18. The Burst Mode of Protostellar Accretion

    NASA Astrophysics Data System (ADS)

    Vorobyov, E. I.; Basu, Shantanu

    2006-10-01

    We present new numerical simulations in the thin disk approximation that characterize the burst mode of protostellar accretion. The burst mode begins upon the formation of a centrifugally balanced disk around a newly formed protostar. It comprises prolonged quiescent periods of low accretion rate (typically <~10-7 Msolar yr-1) that are punctuated by intense bursts of accretion (typically >~10-4 Msolar yr-1, with duration <~100 yr) during which most of the protostellar mass is accumulated. The accretion bursts are associated with the formation of dense protostellar/protoplanetary embryos, which are later driven onto the protostar by the gravitational torques that develop in the disk. Gravitational instability in the disk, driven by continuing infall from the envelope, is shown to be an effective means of transporting angular momentum outward and mass inward to the protostar. We show that the disk mass always remains significantly less than the central protostar's mass throughout this process. The burst phenomenon is robust enough to occur for a variety of initial values of rotation rate and frozen-in (supercritical) magnetic field and a variety of density-temperature relations. Even in cases where the bursts are nearly entirely suppressed, a moderate increase in cloud size or rotation rate can lead to vigorous burst activity. We conclude that most (if not all) protostars undergo a burst mode of evolution during their early accretion history, as inferred empirically from observations of FU Orionis variables.

  19. A statistical algorithm showing coenzyme Q10 and citrate synthase as biomarkers for mitochondrial respiratory chain enzyme activities.

    PubMed

    Yubero, D; Adin, A; Montero, R; Jou, C; Jiménez-Mallebrera, C; García-Cazorla, A; Nascimento, A; O'Callaghan, M M; Montoya, J; Gort, L; Navas, P; Ribes, A; Ugarte, M D; Artuch, R

    2016-12-01

    Laboratory data interpretation for the assessment of complex biological systems remains a great challenge, as occurs in mitochondrial function research studies. The classical biochemical data interpretation of patients versus reference values may be insufficient, and in fact the current classifications of mitochondrial patients are still done on basis of probability criteria. We have developed and applied a mathematic agglomerative algorithm to search for correlations among the different biochemical variables of the mitochondrial respiratory chain in order to identify populations displaying correlation coefficients >0.95. We demonstrated that coenzyme Q10 may be a better biomarker of mitochondrial respiratory chain enzyme activities than the citrate synthase activity. Furthermore, the application of this algorithm may be useful to re-classify mitochondrial patients or to explore associations among other biochemical variables from different biological systems.

  20. Orexin-B antagonized respiratory depression induced by sevoflurane, propofol, and remifentanil in isolated brainstem-spinal cords of neonatal rats.

    PubMed

    Umezawa, Nobuo; Arisaka, Hirofumi; Sakuraba, Shigeki; Sugita, Takeo; Matsumoto, Akiko; Kaku, Yuki; Yoshida, Kazu-ichi; Kuwana, Shun-ichi

    2015-01-01

    Orexins (hypocretins) play a crucial role in arousal, feeding, and endocrine function. We previously reported that orexin-B activated respiratory neurons in the isolated brainstem-spinal cords of neonatal rats. We herein determined whether orexin-B antagonized respiratory depression induced by sevoflurane, propofol, or remifentanil. We recorded C4 nerve bursts as an index of inspiratory activity in a brainstem-spinal cord preparation. The preparation was superfused with a solution equilibrated with 3% sevoflurane alone for 10 min and the superfusate was then switched to a solution containing sevoflurane plus orexin-B. Sevoflurane decreased the C4 burst rate and the integrated C4 amplitude. The C4 burst rate and amplitude were reversed by 0.5 μM orexin-B, but not by 0.1 μM orexin-B. The decrease induced in the C4 burst rate by 10 μM propofol or 0.01 μM remifentanil was significantly antagonized by 0.1 μM orexin-B. Respiratory depression induced by a higher concentration (0.1 μM) of remifentanil was not restored by 0.1 μM orexin-B. These results demonstrated that orexin-B antagonized respiratory depression induced by sevoflurane, propofol, or remifentanil.

  1. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles; Bhat, Narayana; Connaughton, Valerie; Briggs, Michael; Diehl, Roland; Fishman, Gerald; Greiner, Jochen; Kippen, R. Marc; vonKienlin, Andreas; Kouveliotou, Chryssa; Lichti, Giselher; Paciesas, William; Preece, Robert; Steinle, Helmut; Wilson-Hodge, Colleen

    2007-01-01

    The GLAST Burst Monitor (GBM) comprises an array of NaI and BGO scintillation detectors designed to enhance the scientific return from GLAST in the study of gamma-ray bursts (GRBs). By observing in the 10 keV to 30 MeV energy range, GBM extends the spectral coverage of GRBs more than 3 decades below the LAT energy threshold. GBM computes burst locations on-board, allowing repointing of the GLAST Observatory to place strong bursts within the LAT field-of-view to observe delayed high-energy emission.

  2. Propeller tone bursts

    NASA Technical Reports Server (NTRS)

    Succi, G. P.; Munro, D. H.; Ingard, K. U.

    1983-01-01

    Intense high frequency (25-38 kHz) tone bursts have been observed in acoustic tests of a scale model of a general aviation propeller. The amplitude of the tone burst is approximately equal to the amplitude of the propeller noise signature. The conditions necessary for the production of these tone bursts are described. The experiments indicate that the origin of these bursts is a periodic flow oscillation on the suction surface of the propeller blade tips which may be due to the interaction between an oscillating shock wave and a laminar boundary layer.

  3. Depression of mitochondrial respiratory enzyme activity in rostral ventrolateral medulla during acute mevinphos intoxication in the rat.

    PubMed

    Yen, David H T; Chan, Julie Y H; Tseng, H P; Huang, C I; Lee, C H; Chan, Samuel H H; Chang, Alice Y W

    2004-04-01

    We investigated possible changes in bioenergetics at the rostral ventrolateral medulla (RVLM), a medullary site where sympathetic vasomotor tone originates and where the organophosphate poison mevinphos (Mev) acts to elicit cardiovascular intoxication. In Sprague-Dawley rats maintained under propofol anesthesia, microinjection bilaterally of Mev (10 nmol) into the RVLM induced progressive hypotension that was accompanied by an early augmentation (80-100 min post-Mev; Phase I), followed by a decrease (>100 min post-Mev; Phase II) in the power density of the vasomotor components (0-0.8 Hz) in systemic arterial pressure (SAP) signals. Enzyme assay revealed that local application of Mev into the RVLM also significantly and progressively depressed the activity of NADH cytochrome c reductase (marker for Complexes I and III) and cytochrome c oxidase (marker for Complex IV) in the mitochondrial respiratory chain of the RVLM, but not the heart. On the other hand, the activity of succinate cytochrome c reductase (marker for Complexes II and III) remained unaltered. Both the cardiovascular consequences and depression of mitochondrial respiratory chain enzymes elicited by Mev were significantly antagonized on comicroinjection of atropine (3.5 or 7 nmol) bilaterally into the RVLM. We conclude that Mev adversely effects cardiovascular control by acting as a cholinesterase inhibitor in the RVLM, whose neuronal activity is intimately related to the death process. The resulting accumulation of acetylcholine and prolonged activation of muscarinic receptors in the RVLM is manifested by a selective dysfunction of respiratory enzyme Complexes I and IV in the mitochondrial respiratory chain that underlies cardiovascular toxicity associated with organophosphate poisons such as Mev.

  4. Knockdown of sodium channel NaV1.6 blocks mechanical pain and abnormal bursting activity of afferent neurons in inflamed sensory ganglia.

    PubMed

    Xie, Wenrui; Strong, Judith A; Ye, Ling; Mao, Ju-Xian; Zhang, Jun-Ming

    2013-08-01

    Inflammatory processes in the sensory ganglia contribute to many forms of chronic pain. We previously showed that local inflammation of the lumbar sensory ganglia rapidly leads to prolonged mechanical pain behaviors and high levels of spontaneous bursting activity in myelinated cells. Abnormal spontaneous activity of sensory neurons occurs early in many preclinical pain models and initiates many other pathological changes, but its molecular basis is not well understood. The sodium channel isoform NaV1.6 can underlie repetitive firing and excitatory persistent and resurgent currents. We used in vivo knockdown of this channel via local injection of siRNA to examine its role in chronic pain after local inflammation of the rat lumbar sensory ganglia. In normal dorsal root ganglion (DRG), quantitative polymerase chain reaction showed that cells capable of firing repetitively had significantly higher relative expression of NaV1.6. In inflamed DRG, spontaneously active bursting cells expressed high levels of NaV1.6 immunoreactivity. In vivo knockdown of NaV1.6 locally in the lumbar DRG at the time of DRG inflammation completely blocked development of pain behaviors and abnormal spontaneous activity, while having only minor effects on unmyelinated C cells. Current research on isoform-specific sodium channel blockers for chronic pain is largely focused on NaV1.8 because it is present primarily in unmyelinated C fiber nociceptors, or on NaV1.7 because lack of this channel causes congenital indifference to pain. However, the results suggest that NaV1.6 may be a useful therapeutic target for chronic pain and that some pain conditions may be mediated primarily by myelinated A fiber sensory neurons.

  5. Solar S-bursts at Frequencies of 10 - 30 MHz

    NASA Astrophysics Data System (ADS)

    Melnik, V. N.; Konovalenko, A. A.; Rucker, H. O.; Dorovskyy, V. V.; Abranin, E. P.; Lecacheux, A.; Lonskaya, A. S.

    2010-06-01

    Solar S-bursts observed by the radio telescope UTR-2 in the period 2001 - 2002 are studied. The bursts chosen for a detailed analysis occurred in the periods 23 - 26 May 2001, 13 - 16 and 27 - 39 July 2002 during three solar radio storms. More than 800 S-bursts were registered in these days. Properties of S-bursts are studied in the frequency band 10 - 30 MHz. All bursts were always observed against a background of other solar radio activity such as type III and IIIb bursts, type III-like bursts, drift pairs and spikes. Moreover, S-bursts were observed during days when the active region was situated near the central meridian. Characteristic durations of S-bursts were about 0.35 and 0.4 - 0.6 s for the May and July storms, respectively. For the first time, we found that the instantaneous frequency width of S-bursts increased with frequency linearly. The dependence of drift rates on frequency followed the McConnell dependence derived for higher frequencies. We propose a model of S-bursts based on the assumption that these bursts are generated due to the confluence of Langmuir waves with fast magnetosonic waves, whose phase and group velocities are equal.

  6. The Case of the Disappearing Spindle Burst

    PubMed Central

    Tiriac, Alexandre; Blumberg, Mark S.

    2016-01-01

    Sleep spindles are brief cortical oscillations at 10–15 Hz that occur predominantly during non-REM (quiet) sleep in adult mammals and are thought to contribute to learning and memory. Spindle bursts are phenomenologically similar to sleep spindles, but they occur predominantly in early infancy and are triggered by peripheral sensory activity (e.g., by retinal waves); accordingly, spindle bursts are thought to organize neural networks in the developing brain and establish functional links with the sensory periphery. Whereas the spontaneous retinal waves that trigger spindle bursts in visual cortex are a transient feature of early development, the myoclonic twitches that drive spindle bursts in sensorimotor cortex persist into adulthood. Moreover, twitches—and their associated spindle bursts—occur exclusively during REM (active) sleep. Curiously, despite the persistence of twitching into adulthood, twitch-related spindle bursts have not been reported in adult sensorimotor cortex. This raises the question of whether such spindle burst activity does not occur in adulthood or, alternatively, occurs but has yet to be discovered. If twitch-related spindle bursts do occur in adults, they could contribute to the calibration, maintenance, and repair of sensorimotor systems. PMID:27119028

  7. Respiratory acidosis

    MedlinePlus

    ... Names Ventilatory failure; Respiratory failure; Acidosis - respiratory Images Respiratory system References Effros RM, Swenson ER. Acid-base balance. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

  8. Neutrino bursts from gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Paczynski, Bohdan; Xu, Guohong

    1994-01-01

    If gamma-ray bursts originate at cosmological distances, as strongly indicated by the results from Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO), then ultrarelativistic ejecta are the likely consequence of the highly super-Eddington luminosity of the sources. If the energy injection rate varies with time, then the Lorentz factor of the wind also varies, and the shells of ejected matter collide with each other. The collisions between baryons produce pions which decay into high-energy photons, electrons, electron positron pairs, and neutrino pairs. The bulk Lorentz factor of approximately 300 is required if our model is to be compatible with the observed millisecond variability. The strongest gamma-ray bursts are observed to deliver approximately 10(exp -4) ergs/sq cm in 100-200 keV photons. In our scenario more energy may be delivered in a neutrino burst. Typical neutrinos may be approximately 30 GeV if the protons have a Maxwellian energy distribution, and up to approximately TeV if the protons have a power-law distribution. Such neutrino bursts are close to the detection limit of the DUMAND II experiment.

  9. Respiratory Motion of The Heart and Positional Reproducibility Under Active Breathing Control

    SciTech Connect

    Jagsi, Reshma; Moran, Jean M.; Kessler, Marc L.; Marsh, Robin B. C; Balter, James M.; Pierce, Lori J. . E-mail: ljpierce@umich.edu

    2007-05-01

    Purpose: To reduce cardiotoxicity from breast radiotherapy (RT), innovative techniques are under investigation. Information about cardiac motion with respiration and positional reproducibility under active breathing control (ABC) is necessary to evaluate these techniques. Methods and Materials: Patients requiring loco-regional RT for breast cancer were scanned by computed tomography using an ABC device at various breath-hold states, before and during treatment. Ten patients were studied. For each patient, 12 datasets were analyzed. Mutual information-based regional rigid alignment was used to determine the magnitude and reproducibility of cardiac motion as a function of breathing state. For each scan session, motion was quantified by evaluating the displacement of a point along the left anterior descending artery (LAD) with respect to its position at end expiration. Long-term positional reproducibility was also assessed. Results: Displacement of the LAD was greatest in the inferior direction, moderate in the anterior direction, and lowest in the left-right direction. At shallow breathing states, the average displacement of LAD position was up to 6 mm in the inferior direction. The maximum displacement in any patient was 2.8 cm in the inferior direction, between expiration and deep-inspiration breath hold. At end expiration, the long-term reproducibility (SD) of the LAD position was 3 mm in the A-P, 6 mm in the S-I, and 4 mm in the L-R directions. At deep-inspiration breath hold, long-term reproducibility was 3 mm in the A-P, 7 mm in the S-I, and 3 mm in the L-R directions. Conclusions: These data demonstrate the extent of LAD displacement that occurs with shallow breathing and with deep-inspiration breath hold. This information may guide optimization studies considering the effects of respiratory motion and reproducibility of cardiac position on cardiac dose, both with and without ABC.

  10. Activation of necroptosis in a rat model of acute respiratory distress syndrome induced by oleic acid.

    PubMed

    Pan, Long; Yao, Dun-Chen; Yu, Yu-Zhong; Chen, Bing-Jun; Li, Sheng-Jie; Hu, Gui-He; Xi, Chang; Wang, Zi-Hui; Li, Jian-Hua; Long, Jie; Tu, Yong-Sheng

    2016-10-25

    The present study was aimed to investigate the role of necroptosis in the pathogenesis of acute respiratory distress syndrome (ARDS). The rat model of ARDS was induced by intravenous injection of oleic acid (OA), and observed for 4 h. The lung injury was evaluated by arterial blood gas, lung wet-dry weight ratio (W/D) and histological analyses. Simultaneously, bronchoalveolar lavage fluid (BALF) was collected for total and differential cell analysis and total protein determination. Tumor necrosis factor alpha (TNF-α) level in BALF was determined with a rat TNF-α ELISA kit. Expressions of receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like protein (MLKL) in lung tissue were determined by Western blot and immunohistochemical staining. The interaction between RIPK1 and RIPK3 was explored by immunoprecipitation. The results showed that, compared with those in control group, total white blood cells count (WBC), polymorphonuclear percentage (PMN%), total protein concentration, TNF-α level in BALF, W/D, and the alveolar-arterial oxygen tension difference (P(A-a)O2) in OA group were significantly increased at 4 h after OA injection. Western blot and immunostaining further showed remarkably increased expressions of RIPK1, RIPK3 and MLKL in lung tissue from OA group. Additionally, immunoprecipitation results indicated an enforced interaction between RIPK1 and RIPK3 in OA group. Collectively, the TNF-α level in BALF and the RIPK1-RIPK3-MLKL signaling pathway in lung tissue were found to be upregulated and activated with the process of ARDS. These findings implicate that RIPK1/RIPK3-mediated necroptosis plays a possible role in the pathogenesis of ARDS, which may provide a new idea to develop novel drugs for the therapy of ARDS.

  11. Breakthrough curves for toluene adsorption on different types of activated carbon fibers: application in respiratory protection.

    PubMed

    Balanay, Jo Anne G; Floyd, Evan L; Lungu, Claudiu T

    2015-05-01

    Activated carbon fibers (ACF) are considered viable alternative adsorbent materials in respirators because of their larger surface area, lighter weight, and fabric form. The purpose of this study was to characterize the breakthrough curves of toluene for different types of commercially available ACFs to understand their potential service lives in respirators. Two forms of ACF, cloth (AC) and felt (AF), with three surface areas each were tested. ACFs were challenged with six toluene concentrations (50-500 p.p.m.) at constant air temperature (23°C), relative humidity (50%), and air flow (16 l min-1) at different bed depths. Breakthrough data were obtained using continuous monitoring by gas chromatography using a gas sampling valve. The ACF specific surface areas were measured by an automatic physisorption analyzer. Results showed unique shapes of breakthrough curves for each ACF form: AC demonstrated a gradual increase in breakthrough concentration, whereas AF showed abrupt increase in concentration from the breakpoint, which was attributed to the difference in fiber density between the forms. AF has steeper breakthrough curves compared with AC with similar specific surface area. AC exhibits higher 10% breakthrough times for a given bed depth due to higher mass per bed depth compared with AF, indicating more adsorption per bed depth with AC. ACF in respirators may be appropriate for use as protection in environments with toluene concentration at the Occupational Safety and Health Administration Permissible Exposure Limit, or during emergency escape for higher toluene concentrations. ACF has shown great potential for application in respiratory protection against toluene and in the development of thinner, lighter, and more efficient respirators.

  12. Respiratory Viral Infection in Neonatal Piglets Causes Marked Microglia Activation in the Hippocampus and Deficits in Spatial Learning

    PubMed Central

    Elmore, Monica R. P.; Burton, Michael D.; Conrad, Matthew S.; Rytych, Jennifer L.; Van Alstine, William G.

    2014-01-01

    Environmental insults during sensitive periods can affect hippocampal development and function, but little is known about peripheral infection, especially in humans and other animals whose brain is gyrencephalic and experiences major perinatal growth. Using a piglet model, the present study showed that inoculation on postnatal day 7 with the porcine reproductive and respiratory syndrome virus (PRRSV) caused microglial activation within the hippocampus with 82% and 43% of isolated microglia being MHC II+ 13 and 20 d after inoculation, respectively. In control piglets, <5% of microglia isolated from the hippocampus were MHC II+. PRRSV piglets were febrile (p < 0.0001), anorectic (p < 0.0001), and weighed less at the end of the study (p = 0.002) compared with control piglets. Increased inflammatory gene expression (e.g., IL-1β, IL-6, TNF-α, and IFN-γ) was seen across multiple brain regions, including the hippocampus, whereas reductions in CD200, NGF, and MBP were evident. In a test of spatial learning, PRRSV piglets took longer to acquire the task, had a longer latency to choice, and had a higher total distance moved. Overall, these data demonstrate that viral respiratory infection is associated with a marked increase in activated microglia in the hippocampus, neuroinflammation, and impaired performance in a spatial cognitive task. As respiratory infections are common in human neonates and infants, approaches to regulate microglial cell activity are likely to be important. PMID:24501353

  13. Effect of High N-Acetylcysteine Concentrations on Antibiotic Activity against a Large Collection of Respiratory Pathogens

    PubMed Central

    Landini, Giulia; Di Maggio, Tiziana; Sergio, Francesco; Docquier, Jean-Denis; Rossolini, Gian Maria

    2016-01-01

    The effect of high N-acetylcysteine (NAC) concentrations (10 and 50 mM) on antibiotic activity against 40 strains of respiratory pathogens was investigated. NAC compromised the activity of carbapenems (of mostly imipenem and, to lesser extents, meropenem and ertapenem) in a dose-dependent fashion. We demonstrated chemical instability of carbapenems in the presence of NAC. With other antibiotics, 10 mM NAC had no major effects, while 50 mM NAC sporadically decreased (ceftriaxone and aminoglycosides) or increased (penicillins) antibiotic activity. PMID:27736757

  14. Phylogenetic trends in respiratory rhythmogenesis: insights from ectothermic vertebrates.

    PubMed

    Kinkead, Richard

    2009-08-31

    Understanding the neural substrate driving breathing has puzzled physiologists for more than a century. The discovery of the pre-Bötzinger complex (preBötC) in newborn rodents as a structure with a unique physiological function in respiratory rhythm generation was an important progress in respiratory neurobiology that stimulated much research. Owing to the extensive literature describing the location, organisation, and function of the preBötC mainly in newborn rodents, this structure has become the point of reference in studies addressing respiratory rhythm generation in other mammals and various classes of vertebrates. This paper reviews recent progress made in non-mammalian vertebrates in our understanding of the location and function of the neural networks driving respiratory activity. As in newborn rodents, data from lampreys, air breathing fish, and amphibians show that the production of eupnea is the result of interactions between multiple (at least two) rhythmogenic networks. These networks are located in anatomically distinct areas and show different functional properties in terms of their ability to produce (or not) bursting activity in the absence of synaptic inputs (e.g. pacemaker neurons) and their sensitivity to specific neuromodulators such as substance P, somatostatin, and opioids. Current data indicate that respiratory rhythmogenesis is a phylogenetically ancient function that was highly conserved throughout evolution and that a comparative approach remains important to derive broader biological principles and a more comprehensive view.

  15. 5-HT1A receptor-responsive pedunculopontine tegmental neurons suppress REM sleep and respiratory motor activity.

    PubMed

    Grace, Kevin P; Liu, Hattie; Horner, Richard L

    2012-02-01

    Serotonin type 1A (5-HT(1A)) receptor-responsive neurons in the pedunculopontine tegmental nucleus (PPTn) become maximally active immediately before and during rapid eye movement (REM) sleep. A prevailing model of REM sleep generation indicates that activation of such neurons contributes significantly to the generation of REM sleep, and if correct then inactivation of such neurons ought to suppress REM sleep. We test this hypothesis using bilateral microperfusion of the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 10 μm) into the PPTn; this tool has been shown to selectively silence REM sleep-active PPTn neurons while the activity of wake/REM sleep-active PPTn neurons is unaffected. Contrary to the prevailing model, bilateral microperfusion of 8-OH-DPAT into the PPTn (n = 23 rats) significantly increased REM sleep both as a percentage of the total recording time and sleep time, compared with both within-animal vehicle controls and between-animal time-controls. This increased REM sleep resulted from an increased frequency of REM sleep bouts but not their duration, indicating an effect on mechanisms of REM sleep initiation but not maintenance. Furthermore, an increased proportion of the REM sleep bouts stemmed from periods of low REM sleep drive quantified electrographically. Targeted suppression of 5-HT(1A) receptor-responsive PPTn neurons also increased respiratory rate and respiratory-related genioglossus activity, and increased the frequency and amplitude of the sporadic genioglossus activations occurring during REM sleep. These data indicate that 5-HT(1A) receptor-responsive PPTn neurons normally function to restrain REM sleep by elevating the drive threshold for REM sleep induction, and restrain the expression of respiratory rate and motor activities.

  16. The human respiratory gate

    NASA Technical Reports Server (NTRS)

    Eckberg, Dwain L.

    2003-01-01

    Respiratory activity phasically alters membrane potentials of preganglionic vagal and sympathetic motoneurones and continuously modulates their responsiveness to stimulatory inputs. The most obvious manifestation of this 'respiratory gating' is respiratory sinus arrhythmia, the rhythmic fluctuations of electrocardiographic R-R intervals observed in healthy resting humans. Phasic autonomic motoneurone firing, reflecting the throughput of the system, depends importantly on the intensity of stimulatory inputs, such that when levels of stimulation are low (as with high arterial pressure and sympathetic activity, or low arterial pressure and vagal activity), respiratory fluctuations of sympathetic or vagal firing are also low. The respiratory gate has a finite capacity, and high levels of stimulation override the ability of respiration to gate autonomic responsiveness. Autonomic throughput also depends importantly on other factors, including especially, the frequency of breathing, the rate at which the gate opens and closes. Respiratory sinus arrhythmia is small at rapid, and large at slow breathing rates. The strong correlation between systolic pressure and R-R intervals at respiratory frequencies reflects the influence of respiration on these two measures, rather than arterial baroreflex physiology. A wide range of evidence suggests that respiratory activity gates the timing of autonomic motoneurone firing, but does not influence its tonic level. I propose that the most enduring significance of respiratory gating is its use as a precisely controlled experimental tool to tease out and better understand otherwise inaccessible human autonomic neurophysiological mechanisms.

  17. Expiratory activation of abdominal muscle is associated with improved respiratory stability and an increase in minute ventilation in REM epochs of adult rats

    PubMed Central

    Andrews, Colin G.

    2015-01-01

    Breathing is more vulnerable to apneas and irregular breathing patterns during rapid eye movement (REM) sleep in both humans and rodents. We previously reported that robust and recurrent recruitment of expiratory abdominal (ABD) muscle activity is present in rats during REM epochs despite ongoing REM-induced muscle atonia in skeletal musculature. To develop a further understanding of the characteristics of ABD recruitment during REM epochs and their relationship with breathing patterns and irregularities, we sought to compare REM epochs that displayed ABD muscle recruitment with those that did not, within the same rats. Specifically, we investigated respiratory characteristics that preceded and followed recruitment. We hypothesized that ABD muscle recruitment would be likely to occur following respiratory irregularities and would subsequently contribute to respiratory stability and the maintenance of good ventilation following recruitment. Our data demonstrate that epochs of REM sleep containing ABD recruitments (REMABD+) were characterized by increased respiratory rate variability and increased presence of spontaneous brief central apneas. Within these epochs, respiratory events that displayed ABD muscle activation were preceded by periods of increased respiratory rate variability. Onset of ABD muscle activity increased tidal volume, amplitude of diaphragmatic contractions, and minute ventilation compared with the periods preceding ABD muscle activation. These results show that expiratory muscle activity is more likely recruited when respiration is irregular and its recruitment is subsequently associated with an increase in minute ventilation and a more regular respiratory rhythm. PMID:26338455

  18. GABAergic and glycinergic inputs modulate rhythmogenic mechanisms in the lamprey respiratory network

    PubMed Central

    Cinelli, Elenia; Mutolo, Donatella; Robertson, Brita; Grillner, Sten; Contini, Massimo; Pantaleo, Tito; Bongianni, Fulvia

    2014-01-01

    We have previously shown that GABA and glycine modulate respiratory activity in the in vitro brainstem preparations of the lamprey and that blockade of GABAA and glycine receptors restores the respiratory rhythm during apnoea caused by blockade of ionotropic glutamate receptors. However, the neural substrates involved in these effects are unknown. To address this issue, the role of GABAA, GABAB and glycine receptors within the paratrigeminal respiratory group (pTRG), the proposed respiratory central pattern generator, and the vagal motoneuron region was investigated both during apnoea induced by blockade of glutamatergic transmission and under basal conditions through microinjections of specific antagonists. The removal of GABAergic, but not glycinergic transmission within the pTRG, causes the resumption of rhythmic respiratory activity during apnoea, and reveals the presence of a modulatory control of the pTRG under basal conditions. A blockade of GABAA and glycine receptors within the vagal region strongly increases the respiratory frequency through disinhibition of neurons projecting to the pTRG from the vagal region. These neurons were retrogradely labelled (neurobiotin) from the pTRG. Intense GABA immunoreactivity is observed both within the pTRG and the vagal area, which corroborates present findings. The results confirm the pTRG as a primary site of respiratory rhythm generation, and suggest that inhibition modulates the activity of rhythm-generating neurons, without any direct role in burst formation and termination mechanisms. PMID:24492840

  19. A Non-Triggered Burst Supplement to the BATSE Gamma-Ray Burst Catalogs

    NASA Technical Reports Server (NTRS)

    Kommers, J.; Lewin, W. H.; Kouveliotou, C.; vanParadijs, J.; Pendleton, G. N.; Meegan, C. A.; Fishman, G. J.

    1998-01-01

    The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) with a real-time burst detection (or "trigger") system running onboard the spacecraft. Under some circumstances, however, a GRB may not activate the onboard burst trigger. For example, the burst may be too faint to exceed the onboard detection threshold, or it may occur while the onboard burst trigger is disabled for technical reasons. This paper is a catalog of such "non-triggered" GRBs that were detected in a search of the archival continuous data from BATSE. It lists 873 non-triggered bursts that were recorded between 1991 December 9.0 and 1997 December 17.0. For each burst, the catalog gives an estimated source direction, duration, peak flux, and fluence. Similar data are presented for 50 additional bursts of unknown origin that were detected in the 25-50 keV range; these events may represent the low-energy "tail" of the GRB spectral distribution. This catalog increases the number of GRBs detected with BATSE by 48% during the time period covered by the search.

  20. Physical Activity, Cardio-Respiratory Fitness, and Metabolic Traits in Rural Mexican Tarahumara

    PubMed Central

    Christensen, Dirk Lund; Alcalá-Sánchez, Imelda; Leal-Berumen, Irene; Conchas-Ramirez, Miguel; Brage, Soren

    2012-01-01

    Objectives To study the association between physical activity energy expenditure (PAEE) and cardio-respiratory fitness (CRF) with key metabolic traits and anthropometric measures in the Tarahumara of Mexico. Methods A cross-sectional study was carried out in five rural communities in Chihuahua, México including 64 adult Tarahumara, mean (SD) age 40.7 (12.9) years. Using a combined accelerometer and heart rate sensor, PAEE was measured over three consecutive days and nights and a sub-maximal step test was carried out in order to (1) calibrate heart rate at the individual level and (2) to estimate CRF. Random blood glucose level and resting blood pressure (BP) were measured with standard anthropometrics. Results Mean (SD) PAEE was 71.2 (30.3) kJ kg−1 day−1 and CRF was 36.6 (6.5) mlO2 min−1 kg−1. Mean (SD) glucose was 127.9 (32.4) mg/dl, with 3.3% having diabetes. Mean (SD) systolic and diastolic BP was 122 (20.8) and 82 (14.8) mm Hg, respectively, with 28.1% having hypertension. Mean body mass index was 27.5 (4.2) kg m−2, with 71.9% being overweight. Following adjustment for age and sex, weak inverse associations were observed between PAEE and systolic BP (β = −0.20, P = 0.27) and diastolic BP (β = −0.16, P = 0.23); and between CRF and systolic BP (β = −0.51, P = 0.14) and diastolic BP (β = −0.53, P = 0.06). The inverse associations with glucose were also weak and not statistically significant for neither PAEE (β = −0.01, P = 0.63) nor CRF (β = −0.05, P = 0.27). Conclusions This study suggests high levels of overweight and hypertension in the Tarahumara, and points to fitness and physical activity as potential intervention targets although findings should be confirmed in larger samples. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc. PMID:22308165

  1. The effect of artichoke (Cynara scolymus L.) extract on respiratory chain system activity in rat liver mitochondria.

    PubMed

    Juzyszyn, Z; Czerny, B; Myśliwiec, Z; Pawlik, A; Droździk, M

    2010-06-01

    The effect of artichoke extract on mitochondrial respiratory chain (MRC) activity in isolated rat liver mitochondria (including reaction kinetics) was studied. The effect of the extract on the activity of isolated cytochrome oxidase was also studied. Extract in the range of 0.68-2.72 microg/ml demonstrated potent and concentration-dependent inhibitory activity. Concentrations > or =5.4 microg/ml entirely inhibited MRC activity. The succinate oxidase system (MRC complexes II-IV) was the most potently inhibited, its activity at an extract concentration of 1.36 microg/ml being reduced by 63.3% compared with the control (p < 0.05). The results suggest a complex inhibitory mechanism of the extract. Inhibition of the succinate oxidase system was competitive (K(i) = 0.23 microg/ml), whereas isolated cytochrome oxidase was inhibited noncompetitively (K(i) = 126 microg/ml). The results of this study suggest that the salubrious effects of artichoke extracts may rely in part on the effects of their active compounds on the activity of the mitochondrial respiratory chain system.

  2. Modification of the degree of branching of a beta-(1,3)-glucan affects aggregation behavior and activity in an oxidative burst assay.

    PubMed

    Magee, Andrew S; Langeslay, Ryan R; Will, Paul M; Danielson, Michael E; Wurst, Lindsay R; Iiams, Vanessa A

    2015-12-01

    Scleroglucan is a β-(1,3)-glucan which is highly branched at the 6-position with a single glucose residue. Acid hydrolysis of a high molecular weight scleroglucan gave a medium molecular weight, freely soluble material. Linkage analysis by the partially methylated alditol acetate method showed that the solubilized material had 30% branching. When the material was subjected to partial Smith degradations, the percent branching was reduced accordingly to 12% or 17%. After the percent branching was reduced, the average molecular weight of the samples increased considerably, indicating the assembly of higher ordered aggregate structures. An aggregate number distribution analysis was applied to confirm the higher aggregated structures. These aggregated structures gave the material significantly enhanced activity in an in vitro oxidative burst assay compared to the highly branched material.

  3. Air contaminants associated with potential respiratory effects from unconventional resource development activities.

    PubMed

    McCawley, Michael

    2015-06-01

    Unconventional natural gas development uses horizontal drilling in conjunction with hydraulic fracturing to gain access to natural gas deposits which may be tightly held in shale deposits and unavailable to conventional vertical drilling operations. The intensive work required to extract this source of energy results in higher than usual numbers of vehicles involved, potential release of emissions from those vehicles in congested zones surrounding the drill site, and release of other contaminants from materials drawn back out of the borehole after fracturing of the shale. Typical contaminants would be diesel exhaust particulate and gases, volatile organic compounds and other hydrocarbons both from diesels and the drilling process, crystalline silica, used as part of the hydraulic fracturing process in kiloton quantities, and methane escaping from the borehole and piping. A rise in respiratory disease with proximity to the process has been reported in nearby communities and both silica and diesel exposures at the worksite are recognized respiratory hazards. Because of the relatively short time this process has been used to the extent it is currently being used, it is not possible to draw detailed conclusions about the respiratory hazards that may be posed. However, based on the traffic volume associated with each drill site and the number of drill sites in any locale, it is possible at least to compare the effects to that of large traffic volume highways which are known to produce some respiratory effects in surrounding areas.

  4. Learning within the Confines of a Continuing Professional Education Activity: Perspectives from Respiratory Therapists

    ERIC Educational Resources Information Center

    Wittnebel, Leonard D.

    2013-01-01

    Continuing professional education (CPE) for respiratory therapists (RTs) represent both a mandate and a desired characteristic of a profession poised to assume a more prominent role in the healthcare landscape. While it is acknowledged that education beyond the professional degree and a lifetime approach to learning is inherent due to the nature…

  5. SHEBA prompt burst dynamics

    SciTech Connect

    Kimpland, R.

    1997-12-31

    The Solution High-Energy Burst Assembly (SHEBA), located at the Los Alamos Critical Experiments Facility, is a homogeneous liquid-fueled reactor that is being prepared for prompt burst operation. As part of the preparations, a reactor safety study was performed in support of the new SHEBA experiment plan. This study looked at the maximum power, total energy yield, and maximum transient pressures that may occur in the reactor during prompt burst operation. The goal of this study is to analyze the neutronic and hydrodynamic behavior of the reactor during burst operation, and to ensure that prompt burst operation does not damage the reactor or exceed the safety envelope of the facility`s Safety Analysis Report (SAR).

  6. Gamma Ray Bursts - Observations

    NASA Technical Reports Server (NTRS)

    Gehrels, N.; Cannizzo, J. K.

    2010-01-01

    We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high energy emission.

  7. Comparative analysis of signature genes in porcine reproductive and respiratory syndrome virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation statuses of monocytic cells, e.g. monocytes, macrophages and dendritic cells (DCs), are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these cell...

  8. Critical COPD respiratory illness is linked to increased transcriptomic activity of neutrophil proteases genes

    PubMed Central

    2012-01-01

    Background Gene expression profiling (GEP) in cells obtained from peripheral blood has shown that this is a very useful approach for biomarker discovery and for studying molecular pathogenesis of prevalent diseases. While there is limited literature available on gene expression markers associated with Chronic Obstructive Pulmonary Disease (COPD), the transcriptomic picture associated with critical respiratory illness in this disease is not known at the present moment. Findings By using Agilent microarray chips, we have profiled gene expression signatures in the whole blood of 28 COPD patients hospitalized with different degrees of respiratory compromise.12 of them needed of admission to the ICU, whilst 16 were admitted to the Respiratory Medicine Service. GeneSpring GX 11.0 software was used for performing statistical comparisons of transcript levels between ICU and non-ICU patients. Ingenuity pathway analysis 8.5 (IPA) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to select, annotate and visualize genes by function and pathway (gene ontology). T-test showed evidence of 1501 genes differentially expressed between ICU and non-ICU patients. IPA and KEGG analysis of the most representative biological functions revealed that ICU patients had increased levels of neutrophil gene transcripts, being [cathepsin G (CTSG)], [elastase, neutrophil expressed (ELANE)], [proteinase 3 (PRTN3)], [myeloperoxidase (MPO)], [cathepsin D (CTSD)], [defensin, alpha 3, neutrophil-specific (DEFA3)], azurocidin 1 (AZU1)], and [bactericidal/permeability-increasing protein (BPI)] the most representative ones. Proteins codified by these genes form part of the azurophilic granules of neutrophils and are involved in both antimicrobial defence and tissue damage. This “neutrophil signature” was paralleled by the necessity of advanced respiratory and vital support, and the presence of bacterial infection. Conclusion Study of transcriptomic signatures in blood suggests an

  9. Type III Radio Burst Duration and SEP Events

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Makela, P.; Xie, H.

    2010-01-01

    Long-duration (>15 min), low-frequency (<14 MHz) type III radio bursts have been reported to be indicative of solar energetic particle events. We measured the durations of type III bursts associated with large SEP events of solar cycle 23. The Type III durations are distributed symmetrically at 1 MHz yielding a mean value of approximately 33 min (median = 32 min) for the large SEP events. When the SEP events with ground level enhancement (GLE,) are considered, the distribution is essentially unchanged (mean = 32 min, median = 30 min). To test the importance of type III bursts in indicating SEP events, we considered a set of six type III bursts from the same active region (AR 10588) whose durations fit the "long duration" criterion. We analyzed the coronal mass ejections (CMEs), flares, and type II radio bursts associated with the type III bursts. The CMEs were of similar speeds and the flares are also of similar size and duration. All but one of the type III bursts was not associated with a type II burst in the metric or longer wavelength domains. The burst without type II burst also lacked a solar energetic particle (SEP) event at energies >25 MeV. The 1-MHz duration of the type III burst (28 rein) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. This study suggests that the type III burst duration may not be a good indicator of an SEP event, consistent with the statistical study of Cliver and Ling (2009, ApJ ).

  10. Control of abdominal and expiratory intercostal muscle activity during vomiting - Role of ventral respiratory group expiratory neurons

    NASA Technical Reports Server (NTRS)

    Miller, Alan D.; Tan, L. K.; Suzuki, Ichiro

    1987-01-01

    The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal muscle activity during vomiting was investigated in cats. Two series of experiments were performed: in one, the activity of VRG E neurons was recorded during fictive vomiting in cats that were decerebrated, paralyzed, and artificially ventilated; in the second, the abdominal muscle activity during vomiting was compared before and after sectioning the axons of descending VRG E neurons in decerebrate spontaneously breathing cats. The results show that about two-thirds of VRG E neurons that project at least as far caudally as the lower thoracic cord contribute to internal intercostal muscle activity during vomiting. The remaining VRG E neurons contribute to abdominal muscle activation. As shown by severing the axons of the VRG E neurons, other, as yet unidenified, inputs (either descending from the brain stem or arising from spinal reflexes) can also produce abdominal muscle activation.

  11. Induction of Alternatively Activated Macrophages Enhances Pathogenesis during Severe Acute Respiratory Syndrome Coronavirus Infection

    PubMed Central

    Page, Carly; Goicochea, Lindsay; Matthews, Krystal; Zhang, Yong; Klover, Peter; Holtzman, Michael J.; Hennighausen, Lothar

    2012-01-01

    Infection with severe acute respiratory syndrome coronavirus (SARS-CoV) causes acute lung injury (ALI) that often leads to severe lung disease. A mouse model of acute SARS-CoV infection has been helpful in understanding the host response to infection; however, there are still unanswered questions concerning SARS-CoV pathogenesis. We have shown that STAT1 plays an important role in the severity of SARS-CoV pathogenesis and that it is independent of the role of STAT1 in interferon signaling. Mice lacking STAT1 have greater weight loss, severe lung pathology with pre-pulmonary-fibrosis-like lesions, and an altered immune response following infection with SARS-CoV. We hypothesized that STAT1 plays a role in the polarization of the immune response, specifically in macrophages, resulting in a worsened outcome. To test this, we created bone marrow chimeras and cell-type-specific knockouts of STAT1 to identify which cell type(s) is critical to protection from severe lung disease after SARS-CoV infection. Bone marrow chimera experiments demonstrated that hematopoietic cells are responsible for the pathogenesis in STAT1−/− mice, and because of an induction of alternatively activated (AA) macrophages after infection, we hypothesized that the AA macrophages were critical for disease severity. Mice with STAT1 in either monocytes and macrophages (LysM/STAT1) or ciliated lung epithelial cells (FoxJ1/STAT1) deleted were created. Following infection, LysM/STAT1 mice display severe lung pathology, while FoxJ1/STAT1 mice display normal lung pathology. We hypothesized that AA macrophages were responsible for this STAT1-dependent pathology and therefore created STAT1/STAT6−/− double-knockout mice. STAT6 is essential for the development of AA macrophages. Infection of the double-knockout mice displayed a lack of lung disease and prefibrotic lesions, suggesting that AA macrophage production may be the cause of STAT1-dependent lung disease. We propose that the control of AA

  12. Induction of alternatively activated macrophages enhances pathogenesis during severe acute respiratory syndrome coronavirus infection.

    PubMed

    Page, Carly; Goicochea, Lindsay; Matthews, Krystal; Zhang, Yong; Klover, Peter; Holtzman, Michael J; Hennighausen, Lothar; Frieman, Matthew

    2012-12-01

    Infection with severe acute respiratory syndrome coronavirus (SARS-CoV) causes acute lung injury (ALI) that often leads to severe lung disease. A mouse model of acute SARS-CoV infection has been helpful in understanding the host response to infection; however, there are still unanswered questions concerning SARS-CoV pathogenesis. We have shown that STAT1 plays an important role in the severity of SARS-CoV pathogenesis and that it is independent of the role of STAT1 in interferon signaling. Mice lacking STAT1 have greater weight loss, severe lung pathology with pre-pulmonary-fibrosis-like lesions, and an altered immune response following infection with SARS-CoV. We hypothesized that STAT1 plays a role in the polarization of the immune response, specifically in macrophages, resulting in a worsened outcome. To test this, we created bone marrow chimeras and cell-type-specific knockouts of STAT1 to identify which cell type(s) is critical to protection from severe lung disease after SARS-CoV infection. Bone marrow chimera experiments demonstrated that hematopoietic cells are responsible for the pathogenesis in STAT1(-/-) mice, and because of an induction of alternatively activated (AA) macrophages after infection, we hypothesized that the AA macrophages were critical for disease severity. Mice with STAT1 in either monocytes and macrophages (LysM/STAT1) or ciliated lung epithelial cells (FoxJ1/STAT1) deleted were created. Following infection, LysM/STAT1 mice display severe lung pathology, while FoxJ1/STAT1 mice display normal lung pathology. We hypothesized that AA macrophages were responsible for this STAT1-dependent pathology and therefore created STAT1/STAT6(-/-) double-knockout mice. STAT6 is essential for the development of AA macrophages. Infection of the double-knockout mice displayed a lack of lung disease and prefibrotic lesions, suggesting that AA macrophage production may be the cause of STAT1-dependent lung disease. We propose that the control of AA

  13. Respiratory papillomas

    PubMed Central

    Alagusundaramoorthy, Sayee Sundar; Agrawal, Abhinav

    2016-01-01

    Papillomas are known to occur in the lower respiratory tract. They are however, rare compared to their occurrence in the upper respiratory tract. These are generally exophytic tumors in the more proximal upper airways however cases with more distal location with an inverted growth pattern have also been described in the literature. These can be solitary or multiple and multifocality associated with multiple papillomas in the upper respiratory/aerodigestive tract. The four major types of respiratory papillomas are (1) Recurrent respiratory papillomas, (2) solitary squamous papillomas, (3) solitary glandular papillomas, (4) mixed papillomas. We review the incidence, etiopathology, diagnosis, and possible treatment modalities and algorithms for these respiratory papillomas. PMID:27625447

  14. Type III burst pair

    NASA Astrophysics Data System (ADS)

    Ning, Zongjun; Fu, Qijun; Lu, Quankang

    2000-05-01

    We present a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0-2.0 GHz) of the Beijing Astronomical Observatory (BAO). Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. We call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is a nice interpretation of type III burst pair since the plasma beta β~=0.01 is much less than 1 and the beams have velocity of about 1.07×10^8 cm s^-1 after leaving the reconnection region if we assume that the ambient magnetic field strength is about 100 G.

  15. Type III burst pair.

    NASA Astrophysics Data System (ADS)

    Zongjun, Ning; Fu, Qijun; Quankang, Lu

    2000-05-01

    Presents a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0 - 2.0 GHz) of the Beijing Astronomical Observatory. Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. The authors call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is an interpretation of type III burst pair.

  16. In vitro interferon γ improves the oxidative burst activity of neutrophils in patients with chronic granulomatous disease with a subtype of gp91phox deficiency

    PubMed Central

    Uygun, Dilara F. Kocacik; Köksoy, Sadi; Şahin, Emel; Yeğin, Olcay

    2015-01-01

    Aim of this study Chronic granulomatous disease (CGD) is a genetically heterogeneous primary immunodeficiency caused by a defect in phagocyte production of oxygen metabolites, and resulting in infections produced by catalase-positive microorganisms and fungi. Interferon γ (IFN-γ) has a multitude of effects on the immune system. Although preliminary studies with CGD patients on treatment with IFN-γ showed that it enhanced phagocytosis and superoxide production, ongoing studies did not reveal a significant increase of this function. Here we investigated the oxidative capacity of phagocytes in different subtypes of CGD patients on treatment with IFN-γ in vitro. Material and methods Fifty-seven patients with CGD from 14 immunology centres were enrolled to our multi-centre study. Twenty-one patients were studied as controls. Oxidative burst assay with dihydrorhodamine 123 (DHR) was used and the stimulation index (SI) was calculated with respect to CGD subtypes in both neutrophils and monocytes before, and then one and 24 hours after adding IFN-γ. Results Upon comparison of the SIs of the patients’ neutrophils before in vitro IFN-γ at hour 0, and after adding IFN-γ at hour 1 and 24 were compared, and the differences were determined between hours 0-24 and hours 1-24. This difference was especially apparent between hours 1-24. In CGD subtypes, particularly in gp91phox subtype, it was seen that, following in vitro IFN-γ, SIs of neutrophils began to increase after hour 1, and that increase became more apparent at hour 24. Conclusions Our study showed that IFN-γ treatment may increase the oxidative bursting activity by increasing the superoxide production in neutrophils, particularly in gp91phox subtype. PMID:26155184

  17. Cold preservation of isolated hepatocytes in UW solution: experimental studies on the respiratory activity at 0 degrees C.

    PubMed

    Llarrull, Maria Soledad; Pizarro, Maria Dolores; Scandizzi, Angel L; Bottai, Hebe; Guibert, Edgardo E; Rodriguez, Joaquin V

    2007-01-01

    To date, little attention has been paid to the role of the gas milieu in preservation solutions and its effect on cell viability. Dissolved O2 in the preservation media may be an important parameter to consider. In this study we polarographically measured the O2 concentration in air-equilibrated UW solution at 0 degrees C, as well as the respiratory activity of isolated hepatocytes cold-preserved in this solution up to 72 hours. To perform measurements at 0 degrees C, it was first necessary to characterize the sensor behavior at low temperatures. We verified that the sensor response is still linear at this temperature but the rate of response is significantly slower. The O2 solubility in UW-air solution at 0 degrees C was determined using a modified physical method and it was 410 microM O2, which, as expected, is lower than the solubility in water at the same temperature (453 microM O2). Isolated hepatocytes cold-stored in UW-air solution retained a measurable respiratory activity during a period of 72 hours. The O2 consumption rate was 0.48 +/- 0.13 nmol/O2/min/10(6) cells, which represents 1% of the control value at 36 degrees C (61.46 +/- 14.61 nmol/O2/min/10(6) cells). The respiratory activity and cell viability were well maintained during the preservation period. At present, preservation conditions need to be improved for cells to remain functionally active. Dissolved O2 may be required for energy re-synthesis but it also leads to an increment in reactive oxygen species. The O2 concentration in the preservation solution should be carefully controlled, reaching a compromise between cell requirement and toxicity.

  18. Respiratory Failure

    MedlinePlus

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  19. Respiratory system

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G., Jr.

    1973-01-01

    The general anatomy and function of the human respiratory system is summarized. Breathing movements, control of breathing, lung volumes and capacities, mechanical relations, and factors relevant to respiratory support and equipment design are discussed.

  20. On vortex bursting

    NASA Technical Reports Server (NTRS)

    Werle, H.

    1984-01-01

    Vortex bursting is studied by means of visualization. The physical behavior of the phenomenon is emphasized, and its similarity with boundary layer separation or wake bursting becomes apparent. The essential influence of an increasing pressure gradient on the initiation, the position and the type of bursting is clearly confirmed. The evolution of the phenomena as a function of several parameters is analyzed in the case of delta wings, alone or installed on aircraft models, and compared with the results of similar wind tunnel or flight tests.

  1. Serotonergic mechanisms are necessary for central respiratory chemoresponsiveness in situ

    PubMed Central

    Corcoran, Andrea E.; Richerson, George B.; Harris, Michael B.

    2013-01-01

    Evidence from in vivo and in vitro experiments conclude that serotonin (5-HT) neurons are involved in and play an important role in central respiratory CO2/H+ chemosensitivity. This study was designed to assess the importance of 5-HT neurons and 5-HT receptor activation in the frequency and amplitude components of the hypercapnic response of the respiratory network in the unanesthetized perfused in situ juvenile rat brainstem preparation that exhibits patterns of phrenic nerve discharge similar to breathing in vivo. Exposure to a hypercapnic perfusate increased phrenic burst frequency and/or amplitude, the neural correlates of breathing frequency and tidal volume in vivo. Hypercapnic responses were also assessed during exposure to ketanserin (5-HT2 receptor antagonist), and 8-OH-DPAT (inhibiting 5-HT neurons via 5-HT1A autoreceptors). Neither of these drugs substantially altered baseline activity, however, both abolished hypercapnic responses of the respiratory network. These data illustrate that 5-HT neurons and 5-HT receptor activation are not required for respiratory rhythm generation per se, but are critical for CO2 responses in situ, supporting the hypothesis that 5-HT neurons play an important role in central ventilatory chemosensitivity in vivo. PMID:23454177

  2. Respiratory alkalosis

    MedlinePlus

    ... shortness of breath. Alternative Names Alkalosis - respiratory Images Respiratory system References Effros RM, Swenson ER. Acid-base balance. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

  3. A Nontriggered Burst Supplement to the BATSE Gamma-Ray Burst Catalogs

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2001-01-01

    The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) with a real-time burst detection (or "trigger") system running onboard the spacecraft. Under some circumstances, however, a GRB may not activate the on-board burst trigger. For example, the burst may be too faint to exceed the on-board detection threshold, or it may occur while the on-board burst trigger is disabled for technical reasons. This paper describes a catalog of 873 "nontriggered" GRBs that were detected in a search of the archival continuous data from BATSE recorded between 1991 December 9.0 and 1997 December 17.0. For each burst, the catalog gives an estimated source direction, duration, peak flux, and fluence. Similar data are presented for 50 additional bursts of unknown origin that were detected in the 25-50 keV range; these events may represent the low-energy "tail" of the GRB spectral distribution. This catalog increases the number of GRBs detected with BATSE by 48% during the time period covered by the search.

  4. Alteration of bursting properties in interneurons during locust flight.

    PubMed

    Ramirez, J M; Pearson, K G

    1993-11-01

    1. The contribution of bursting properties to the generation of the flight motor pattern was examined for two identified interneurons (interneurons 566 and 567) in the flight system of the locust Locusta migratoria by means of intracellular recording and stimulation techniques. These interneurons are important elements in transmitting proprioceptive information from the hindwing tegula to wing elevator motoneurons. 2. Offset currents injected into these neurons revealed that bursts are triggered in the intact flying animal by synaptic input from tegula afferents (n = 10). These bursts lead to an amplification of proprioceptive input that is crucial for the generation of the intact flight motor pattern. In the absence of afferent input the activity of these neurons remained subthreshold for triggering a burst. This explains why these neurons exhibit only weak rhythmic oscillations in deafferented animals. 3. The property of interneuron 566 to burst was conditional, always being expressed during flight (n = 14) and occurring only occasionally in the quiescent animal. In the absence of flight, stimulation of tegula afferents never evoked bursts in interneuron 566 (n = 7) and depolarizing current pulses evoked weak bursts in only three of nine preparations. In 2 of 14 animals, bursting property of interneuron 566 was enhanced just after the termination of flight. 4. Variability in the bursting property was also found for interneuron 567. In the quiescent animal, tegula-evoked compound excitatory postsynaptic potentials were not sufficient to trigger bursts (n = 3) but depolarizing current pulses evoked always weak rhythmic bursting activity (n = 4). This bursting property was also variable and in one animal we found long-lasting plateau potentials that could be evoked by current injection after flight was elicited several times. 5. The data presented demonstrate that the capacity to burst is conditional in the interneurons 566 and 567. Bursting properties are always

  5. INTEGRAL burst alert service

    NASA Technical Reports Server (NTRS)

    Pedersen, H.; Jennings, D.; Mereghetti, S.; Teegarden, B.

    1997-01-01

    The detection, accurate positioning, and spectral analysis of cosmic gamma ray bursts is an objective of the International Gamma Ray Astrophysics Laboratory (INTEGRAL) mission. Due to their unpredictable nature, gamma ray bursts can only be observed in serendipity mode. In order to allow and promote multiwavelength follow-up observations of such events, it is desirable to make the information available to the astrophysics community with a minimum delay through the use of Internet. Ideally, the data dissemination should occur within a few seconds of the start of the burst event so that follow up observations can proceed while gamma rays are still being emitted. The technical feasibility of building such a system to disseminate INTEGRAL burst alerts in real time is currently under consideration, the preliminary results of which are presented. It is concluded that such an alert service is technically feasible.

  6. CMEs and frequency cutoff of solar bursts

    NASA Astrophysics Data System (ADS)

    Stanislavsky, Al.; Konovalenko, Al.; Koval, Ar.; Volvach, Y.; Zarka, P.

    2016-05-01

    Radio observations of solar bursts with high-frequency cutoff by the radio telescope UTR-2 (near Kharkiv, Ukraine) at 8-33 MHz on 17-19 August 2012 are presented. Such cutoff may be attributed to the emergence of the burst sources behind limb of the Sun with respect to an observer on the Earth. The events are strongly associated with solar eruptions occurred in a new active region. Ray tracing simulations show that the CMEs play a constructive role for the behind-limb bursts to be detected in ground-based observations. Likely, due to tunnel-like cavities with low density in CMEs, the radio emission of behind-limb solar bursts can be directed towards the Earth.

  7. GLAST's GBM Burst Trigger

    NASA Technical Reports Server (NTRS)

    Band, D.; Briggs, M.; Connaughton, V.; Kippen, M.; Preece, R.

    2003-01-01

    The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

  8. Respiratory muscle plasticity.

    PubMed

    Rowley, Katharine L; Mantilla, Carlos B; Sieck, Gary C

    2005-07-28

    Plasticity of respiratory muscles must be considered in the context of their unique physiological demands. The continuous rhythmic activation of respiratory muscles makes them among the most active in the body. Respiratory muscles, especially the diaphragm, are non-weight-bearing, and thus, in contrast to limb muscles, are not exposed to gravitational effects. Perturbations in normal activation and load known to induce plasticity in limb muscles may not cause similar adaptations in respiratory muscles. In this review, we explore the structural and functional properties of the diaphragm muscle and their response to alterations in load and activity. Overall, relatively modest changes in diaphragm structural and functional properties occur in response to perturbations in load or activity. However, disruptions in the normal influence of phrenic innervation by frank denervation, tetrodotoxin nerve block and spinal hemisection, induce profound changes in the diaphragm, indicating the substantial trophic influence of phrenic motoneurons on diaphragm muscle.

  9. [Respiratory responses to microinjections of leptin into the solitary tract nucleus].

    PubMed

    Iniushkin, A N; Iniushkina, E M; Merkulova, N A

    2008-01-01

    Regulatory polypeptide leptin, apart from its well-known hypothalamic effects, stimulates ventilation. The present study on anaesthetised rats was undertaken to elucidate the respiratory effects of 10(-10)-10(-4) M leptin microinjected into the solitary tract nucleus, containing a high concentration of leptin receptors. Injections of 10(-8)-10(-4) M leptin induced dose-dependent increase in ventilation, tidal volume and electric activity of inspiratory muscles; 10(-6) M leptin additionally induced a short-term increase in respiratory frequency and a shortening of both inspiratory and expiratory duration. The respiratory responses to leptin is also characterised by appearance of sighs: deep and prolonged inspirations associated with an augmented burst in the activity of the inspiratory muscles and prolonged post-sigh inter-burst interval. The results taken together with evidence of high concentration of specific leptin ObRb-receptor in the solitary tract nucleus suggest involvement of endogenous leptin in the control of breathing via dorsal structures of the respiratory center.

  10. The relative importance of respiratory water loss in scorpions is correlated with species habitat type and activity pattern.

    PubMed

    Gefen, Eran

    2011-01-01

    Scorpions exhibit some of the lowest recorded water loss rates compared with those of other terrestrial arthropods of similar body size. Evaporative water loss (EWL) includes cuticular transpiration and respiratory water loss (RWL) from gas exchange surfaces, that is, book lung lamellae. Estimated fractions of cuticular and respiratory losses currently available from the literature show considerable variation, at least partly as a result of differences in methodology. This study reports RWL rates and their relative importance in scorpions from two families (Buthidae and Scorpionidae), including both xeric and mesic species (or subspecies). Two of the included Buthidae were surface-dwelling species, and another inhabits empty burrows of other terrestrial arthropods. This experimental design enabled correlating RWL importance with scorpion phylogeny, habitat type, and/or homing behavior. Buthidae species exhibited significantly lower EWL rates compared with those of Scorpionidae, whereas effects of habitat type and homing behavior were not significant. Resting RWL rates were not significantly affected by scorpion phylogeny, but rates for the xeric species (totaling ~10% of EWL rates at 30°C) were significantly lower compared with those of mesic species. These lower RWL values were correlated with significantly lower H(2)O/CO(2) emission rates in xeric species. The experimental setup and ~24-h duration of each individual recording allowed estimating the effect of interspecific variation in activity on RWL proportions. The high respiratory losses in active hydrated Scorpio maurus fuscus, totaling 30% of EWL, suggest that behavioral discretion in this species is a more likely mechanism for body water conservation under stressful conditions when compared with the responses of other studied species.

  11. Respiratory muscle activity during REM sleep in patients with diaphragm paralysis.

    PubMed

    Bennett, J R; Dunroy, H M A; Corfield, D R; Hart, N; Simonds, A K; Polkey, M I; Morrell, M J

    2004-01-13

    The diaphragm is the main inspiratory muscle during REM sleep. It was hypothesized that patients with isolated bilateral diaphragm paralysis (BDP) might not be able to sustain REM sleep. Polysomnography with EMG recordings was undertaken from accessory respiratory muscles in patients with BDP and normal subjects. Patients with BDP had a normal quantity of REM sleep (mean +/- SD, 18.6 +/- 7.5% of total sleep time) achieved by inspiratory recruitment of extradiaphragmatic muscles in both tonic and phasic REM, suggesting brainstem reorganization.

  12. Efficacy of high-flow oxygen by nasal cannula with active humidification in a patient with acute respiratory failure of neuromuscular origin.

    PubMed

    Díaz-Lobato, Salvador; Folgado, Miguel Angel; Chapa, Angel; Mayoralas Alises, Sagrario

    2013-12-01

    The treatment of choice for patients with respiratory failure of neuromuscular origin, especially in patients with hypercapnic respiratory acidosis, is noninvasive ventilation (NIV). Endotracheal intubation and invasive ventilation are indicated for patients with severe respiratory compromise or failure of NIV. In recent years, high-flow oxygen therapy and active humidification devices have been introduced, and emerging evidence suggests that high-flow oxygen may be effective in various clinical settings, such as acute respiratory failure, after cardiac surgery, during sedation and analgesia, in acute heart failure, in hypoxemic respiratory distress, in do-not-intubate patients, in patients with chronic cough and copious secretions, pulmonary fibrosis, or cancer, in critical areas and the emergency department. We report on a patient with amyotrophic lateral sclerosis who arrived at the emergency department with acute hypercapnic respiratory failure. She did not tolerate NIV and refused intubation, but was treated successfully with heated, humidified oxygen via high-flow nasal cannula. Arterial blood analysis after an hour on high-flow nasal cannula showed improved pH, P(aCO2), and awareness. The respiratory acidosis was corrected, and she was discharged after 5 days of hospitalization. Her response to high-flow nasal cannula was similar to that expected with NIV. We discuss the mechanisms of action of heated, humidified high-flow oxygen therapy.

  13. Dexmedetomidine and clonidine induce long-lasting activation of the respiratory rhythm generator of neonatal mice: possible implication for critical care.

    PubMed

    Voituron, Nicolas; Hilaire, Gérard; Quintin, Luc

    2012-01-15

    Dexmedetomidine and clonidine are alpha-2 adrenoceptor agonists increasingly used in the critical care unit as sedative agents for their benzodiazepine-sparing effects and their limited depressing effect on breathing. However adverse effects on breathing have been also reported with alpha-2 adrenoceptor agonists and their central effects on the respiratory rhythm generator are poorly known. We therefore examined the effects of dexmedetomidine, clonidine, the alpha-2 adrenoceptor antagonist yohimbine and the benzodiazepine midazolam on the activity of the isolated respiratory rhythm generator of neonatal mice using medullary preparations where the respiratory rhythm generator continued to function in vitro. For the first time, we showed that 5min bath applications of dexmedetomidine or clonidine activated the respiratory rhythm generator for periods over than 30min. Second, we showed that the long-lasting effect of dexmedetomidine implicated receptors other than alpha-2 adrenoceptors as it persisted after their blockade with yohimbine. Third, we reported that 5min bath applications of the benzodiazepine midazolam significantly depressed the respiratory rhythm generator, and that this depression was prevented by pre-treatment with either dexmedetomidine or clonidine. Although further experiments are still required to identify the mechanisms through which dexmedetomidine and clonidine activate the respiratory rhythm generator, our current in vitro results in neonatal mice support the use of dexmedetomidine and clonidine in the critical care unit.

  14. Nuclear respiratory factors 1 and 2 utilize similar glutamine-containing clusters of hydrophobic residues to activate transcription.

    PubMed Central

    Gugneja, S; Virbasius, C M; Scarpulla, R C

    1996-01-01

    Nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2) are ubiquitous transcription factors that have been implicated in the control of nuclear genes required for respiration, heme biosynthesis, and mitochondrial DNA transcription and replication. Recently, both factors have been found to be major transcriptional determinants for a subset of these genes that define a class of simple promoters involved in respiratory chain expression. Here, functional domains required for transactivation by NRF-1 have been defined. An atypical nuclear localization signal resides in a conserved amino-terminal region adjacent to the DNA binding domain and consists of functionally redundant clusters of basic residues. A second domain in the carboxy-terminal half of the molecule is necessary for transcriptional activation. The activation domains of both NRF-1 and NRF-2 were extensively characterized by both deletion and alanine substitution mutagenesis. The results show that these domains do not fall into known classes defined by a preponderance of amino acid residues, including glutamines, prolines, or isoleucines, as found in other eukaryotic activators. Rather, in both factors, a series of tandemly arranged clusters of hydrophobic amino acids were required for activation. Although all of the functional clusters contain glutamines, the glutamines differ from the hydrophobic residues in that they are inconsequential for activation. Unlike the NRF-2 domain, which contains its essential hydrophobic motifs within 40 residues, the NRF-1 domain spans about 40% of the molecule and appears to have a bipartite structure. The findings indicate that NRF-1 and NRF-2 utilize similar hydrophobic structural motifs for activating transcription. PMID:8816484

  15. Expression of the Bovine NK-Lysin Gene Family and Activity against Respiratory Pathogens

    PubMed Central

    Chen, Junfeng; Yang, Chingyuan; Tizioto, Polyana C.; Huang, Huan; Lee, Mi O. K.; Payne, Harold R.; Lawhon, Sara D.; Schroeder, Friedhelm; Taylor, Jeremy F.; Womack, James E.

    2016-01-01

    Unlike the genomes of many mammals that have a single NK-lysin gene, the cattle genome contains a family of four genes, one of which is expressed preferentially in the lung. In this study, we compared the expression of the four bovine NK-lysin genes in healthy animals to animals challenged with pathogens known to be associated with bovine respiratory disease (BRD) using transcriptome sequencing (RNA-seq). The expression of several NK-lysins, especially NK2C, was elevated in challenged relative to control animals. The effects of synthetic peptides corresponding to functional region helices 2 and 3 of each gene product were tested on both model membranes and bio-membranes. Circular dichroism spectroscopy indicated that these peptides adopted a more helical secondary structure upon binding to an anionic model membrane and liposome leakage assays suggested that these peptides disrupt membranes. Bacterial killing assays further confirmed the antimicrobial effects of these peptides on BRD-associated bacteria, including both Pasteurella multocida and Mannhemia haemolytica and an ultrastructural examination of NK-lysin-treated P. multocida cells by transmission electron microscopy revealed the lysis of target membranes. These studies demonstrate that the expanded bovine NK-lysin gene family is potentially important in host defense against pathogens involved in bovine respiratory disease. PMID:27409794

  16. Automated determination of wakefulness and sleep in rats based on non-invasively acquired measures of movement and respiratory activity.

    PubMed

    Zeng, Tao; Mott, Christopher; Mollicone, Daniel; Sanford, Larry D

    2012-03-15

    The current standard for monitoring sleep in rats requires labor intensive surgical procedures and the implantation of chronic electrodes which have the potential to impact behavior and sleep. With the goal of developing a non-invasive method to determine sleep and wakefulness, we constructed a non-contact monitoring system to measure movement and respiratory activity using signals acquired with pulse Doppler radar and from digitized video analysis. A set of 23 frequency and time-domain features were derived from these signals and were calculated in 10s epochs. Based on these features, a classification method for automated scoring of wakefulness, non-rapid eye movement sleep (NREM) and REM in rats was developed using a support vector machine (SVM). We then assessed the utility of the automated scoring system in discriminating wakefulness and sleep by comparing the results to standard scoring of wakefulness and sleep based on concurrently recorded EEG and EMG. Agreement between SVM automated scoring based on selected features and visual scores based on EEG and EMG were approximately 91% for wakefulness, 84% for NREM and 70% for REM. The results indicate that automated scoring based on non-invasively acquired movement and respiratory activity will be useful for studies requiring discrimination of wakefulness and sleep. However, additional information or signals will be needed to improve discrimination of NREM and REM episodes within sleep.

  17. East Coast Fever Caused by Theileria parva Is Characterized by Macrophage Activation Associated with Vasculitis and Respiratory Failure

    PubMed Central

    Schneider, David A.; Frevert, Charles W.; Nelson, Danielle D.; Morrison, W. Ivan; Knowles, Donald P.

    2016-01-01

    Respiratory failure and death in East Coast Fever (ECF), a clinical syndrome of African cattle caused by the apicomplexan parasite Theileria parva, has historically been attributed to pulmonary infiltration by infected lymphocytes. However, immunohistochemical staining of tissue from T. parva infected cattle revealed large numbers of CD3- and CD20-negative intralesional mononuclear cells. Due to this finding, we hypothesized that macrophages play an important role in Theileria parva disease pathogenesis. Data presented here demonstrates that terminal ECF in both Holstein and Boran cattle is largely due to multisystemic histiocytic responses and resultant tissue damage. Furthermore, the combination of these histologic changes with the clinical findings, including lymphadenopathy, prolonged pyrexia, multi-lineage leukopenia, and thrombocytopenia is consistent with macrophage activation syndrome. All animals that succumbed to infection exhibited lymphohistiocytic vasculitis of small to medium caliber blood and lymphatic vessels. In pulmonary, lymphoid, splenic and hepatic tissues from Holstein cattle, the majority of intralesional macrophages were positive for CD163, and often expressed large amounts of IL-17. These data define a terminal ECF pathogenesis in which parasite-driven lymphoproliferation leads to secondary systemic macrophage activation syndrome, mononuclear vasculitis, pulmonary edema, respiratory failure and death. The accompanying macrophage phenotype defined by CD163 and IL-17 is presented in the context of this pathogenesis. PMID:27195791

  18. Activation of the epidermal growth factor receptor by respiratory syncytial virus results in increased inflammation and delayed apoptosis.

    PubMed

    Monick, Martha M; Cameron, Kelli; Staber, Janice; Powers, Linda S; Yarovinsky, Timur O; Koland, John G; Hunninghake, Gary W

    2005-01-21

    Respiratory syncytial virus (RSV) preferentially infects lung epithelial cells. Infection by RSV leads to an extended inflammatory response, characterized by the release of interleukin-8 (IL-8). Activation of ERK MAP kinase is required for both RSV-induced inflammation and the extended survival of infected cells. In this study, we analyzed the role of the epidermal growth factor receptor (EGFR) in RSV activation of ERK. We demonstrate for the first time that RSV activates EGFR in lung epithelial cells. Activation of EGFR results in increased ERK activity, contributing to both the inflammatory response (IL-8 release) and prolonging the survival of RSV-infected cells. Inhibition of EGFR with siRNA decreased both ERK activation and IL-8 production after RSV. In analyzing the effect of EGFR activation on survival of RSV-infected cells, we found that EGFR activation by RSV resulted in ERK-dependent alterations in the balance of pro- versus anti-apoptotic Bcl2 proteins. RSV altered the balance between pro- and anti-apoptotic Bcl2 proteins (increased BclxL and decreased BimEL) increasing the relative amount of pro-survival proteins. This occurred in an EGFR-dependent manner. This study supports an important role for EGFR activity in the lifespan and inflammatory potential of RSV-infected epithelial cells.

  19. Phase analysis method for burst onset prediction

    NASA Astrophysics Data System (ADS)

    Stellino, Flavio; Mazzoni, Alberto; Storace, Marco

    2017-02-01

    The response of bursting neurons to fluctuating inputs is usually hard to predict, due to their strong nonlinearity. For the same reason, decoding the injected stimulus from the activity of a bursting neuron is generally difficult. In this paper we propose a method describing (for neuron models) a mechanism of phase coding relating the burst onsets with the phase profile of the input current. This relation suggests that burst onset may provide a way for postsynaptic neurons to track the input phase. Moreover, we define a method of phase decoding to solve the inverse problem and estimate the likelihood of burst onset given the input state. Both methods are presented here in a unified framework, describing a complete coding-decoding procedure. This procedure is tested by using different neuron models, stimulated with different inputs (stochastic, sinusoidal, up, and down states). The results obtained show the efficacy and broad range of application of the proposed methods. Possible applications range from the study of sensory information processing, in which phase-of-firing codes are known to play a crucial role, to clinical applications such as deep brain stimulation, helping to design stimuli in order to trigger or prevent neural bursting.

  20. Effect of mitochondrial genome rearrangement on respiratory activity, photosynthesis, photorespiration and energy status of MSC16 cucumber (Cucumis sativus) mutant.

    PubMed

    Juszczuk, Izabela M; Flexas, Jaume; Szal, Bozena; Dabrowska, Zofia; Ribas-Carbo, Miquel; Rychter, Anna M

    2007-12-01

    The effects of changes in mitochondrial DNA in cucumber (Cucumis sativus L.) mosaic mutant (MSC16) on respiration, photosynthesis and photorespiration were analyzed under non-stressed conditions. Decreased respiratory capacity of complex I in MSC16 mitochondria was indicated by lower respiration rates of intact mitochondria with malate and by rotenone-inhibited NADH or malate oxidation in the presence of alamethicin. Moreover, blue native PAGE indicated decreased intensity of protein bands of respiratory chain complex I in MSC16 leaves. Concerning the redox state, complex I impairment could be compensated to some extent by increased external NADH dehydrogenases (ND(ex)NADH) and alternative oxidase (AOX) capacity, the latter presenting differential expression in the light and in the dark. Although MSC16 mitochondria have a higher AOX protein level and an increased capacity, the AOX activity measured in the dark conditions by oxygen discrimination technique is similar to that in wild-type (WT) plants. Photosynthesis induction by light followed different patterns in WT and MSC16, suggesting changes in feedback chloroplast DeltapH caused by different adenylate levels. At steady-state, net photosynthesis was only slightly impaired in MSC16 mutants, while photorespiration rate (PR) was significantly increased. This was the result of large decreases in both stomatal and mesophyll conductance to CO2, which resulted in a lower CO2 concentration in the chloroplasts. The observed changes on CO2 diffusion caused by mitochondrial mutations open a whole new view of interaction between organelle metabolism and whole tissue physiology. The sum of all the described changes in photosynthetic and respiratory metabolism resulted in a lower ATP availability and a slower plant growth.

  1. Respiratory alkalosis.

    PubMed

    Foster, G T; Vaziri, N D; Sassoon, C S

    2001-04-01

    Respiratory alkalosis is an extremely common and complicated problem affecting virtually every organ system in the body. This article reviews the various facets of this interesting problem. Respiratory alkalosis produces multiple metabolic abnormalities, from changes in potassium, phosphate, and calcium, to the development of a mild lactic acidosis. Renal handling of the above ions is also affected. The etiologies may be related to pulmonary or extrapulmonary disorders. Hyperventilation syndrome is a common etiology of respiratory alkalosis in the emergency department setting and is a diagnosis by exclusion. There are many cardiac effects of respiratory alkalosis, such as tachycardia, ventricular and atrial arrhythmias, and ischemic and nonischemic chest pain. In the lungs, vasodilation occurs, and in the gastrointestinal system there are changes in perfusion, motility, and electrolyte handling. Therapeutically, respiratory alkalosis is used for treatment of elevated intracranial pressure. Correction of a respiratory alkalosis is best performed by correcting the underlying etiology.

  2. Effects of ambient ozone on respiratory function in active, normal children

    SciTech Connect

    Spektor, D.M.; Lippmann, M.; Lioy, P.J.; Thurston, G.D.; Citak, K.

    1988-01-01

    Respiratory functions were measured daily by spirometry over four weeks at a summer camp in northwestern New Jersey. Multiple regression analyses indicated that O{sub 3} concentration, cumulative daily O{sub 3} exposure, ambient temperature, and humidity were the most explanatory environmental variables for daily variations in function, and that O{sub 3} concentration had the strongest influence on FVC, PEFR, and MMEf. For FEV1, cumulative daily O{sub 3} exposure and heat stress had greater relative effects. Linear regressions were performed for each child between O{sub 3} concentration and function, and all average slopes were significantly negative (p <0.05) for PVC, FEV1, PEFR and MMEF for all children, and for boys and girls separately. The implications of these short-term effects are unknown. However, the results in these free living children are comparable to those found in chamber studies with comparable exposures.

  3. Glucagon treatment of rats activates the respiratory chain of liver mitochondria at more than one site.

    PubMed

    Halestrap, A P

    1987-02-18

    The rate of reduction of ferricyanide in the presence and absence of antimycin and ubiquinone-1 was measured using liver mitochondria from control and glucagon treated rats. Glucagon treatment was shown to increase electron flow from both NADH and succinate to ubiquinone, and from ubiquinone to cytochrome c. 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was shown to inhibit the oxidation of glutamate + malate to a much greater extent than that of succinate or duroquinol. Spectral and kinetic studies confirmed that electron flow between NADH and ubiquinone was the primary site of action but that the interaction of the ubiquinone pool with complex 3 was also affected. The effects of various respiratory chain inhibitors on the rate of uncoupled oxidation of succinate and glutamate + malate by control and glucagon treated mitochondria were studied. The stimulation of respiration seen in the mitochondria from glucagon treated rats was maintained or increased as respiration was progressively inhibited with DCMU, 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), 2-heptyl-4-hydroxyquinoline-n-oxide (HQNO) and colletotrichin, but greatly reduced when inhibition was produced with malonate or antimycin. These data were also shown to support the conclusion that glucagon treatment may cause some stimulation of electron flow through NADH dehydrogenase, succinate dehydrogenase and through the bc1 complex, probably at the point of interaction of the complexes with the ubiquinone pool. The effects of glucagon treatment on duroquinol oxidation and the inhibitor titrations could not be mimicked by increasing the matrix volume, nor totally reversed by aging of mitochondria. These are both processes that have been suggested as the means by which glucagon exerts its effects on the respiratory chain (Armston, A.E., Halestrap, A.P. and Scott, R.D., 1982, Biochim. Biophys. Acta 681, 429-439). It is concluded that an additional mechanism for regulating electron flow must exist and a

  4. Pathologic changes induced in respiratory tract mucosa by polycyclic hydrocarbons of differing carcinogenic activity.

    PubMed Central

    Topping, D. C.; Pal, B. C.; Martin, D. H.; Nelson, F. R.; Nettesheim, P.

    1978-01-01

    Seven aromatic polycyclic hydrocarbons (PCHs) were investigated for their toxic effects on respiratory mucosa: benzo(e)pyrene (BeP), pyrene, anthracene, benz(a)anthracene(BaA), dibenz(a,c)anthracene(DBacA), benzo (a)pyrene (BaP), and dimethylbenz(a)anthracene (DMBA). The compounds were chosen because they comprise a spectrum of PCHs ranging from noncarcinogens, to initiators, to weak and strong carcinogens. All of them except DMBA are environmentally relevant chemicals. The chemicals were tested over an 8-week period. Heterotopic tracheal transplants were continously exposed and the histopathologic effects induced by the various PCHs were periodically assessed semiquantitatively. All PCHs exhibited varying degrees of toxicity for respiratory epithelium and submucosa. BeP clearly showed the least toxicity followed by pyrene and anthracene. BaA and DBacA caused marked epithelial and submucosal changes. In addition to epithelial hyperplasia, undifferentiated epithelium and squamous metaplasia developed. Marked mononuclear infiltration occurred in the subepithelial connective tissue. With BaP the epithelial and submucosal changes were similar but were much stronger. DMBA was the most toxic substance, causing epithelial necrosis followed by generalized keratinizing squamous metaplasia; the subepithelial changes consisted of an early acellular exudate and, later (at 8 weeks), marked condensation and hyalinization of the lamina propria. The toxic response pattern of the tracheal mucosa to carcinogenic agents was characterized by the chronicity of epithelial and connective tissue damage, as opposed to the short-lived hyperplastic and inflammatory response elicited by the noncarcinogens and weak initiators. Images Figure 2 Figure 1 PMID:102204

  5. Intermittent Theta Burst Over M1 May Increase Peak Power of a Wingate Anaerobic Test and Prevent the Reduction of Voluntary Activation Measured with Transcranial Magnetic Stimulation.

    PubMed

    Giboin, Louis-Solal; Thumm, Patrick; Bertschinger, Raphael; Gruber, Markus

    2016-01-01

    Despite the potential of repetitive transcranial magnetic stimulation (rTMS) to improve performances in patients suffering from motor neuronal afflictions, its effect on motor performance enhancement in healthy subjects during a specific sport task is still unknown. We hypothesized that after an intermittent theta burst (iTBS) treatment, performance during the Wingate Anaerobic Test (WAnT) will increase and supraspinal fatigue following the exercise will be lower in comparison to a control treatment. Ten subjects participated in two randomized experiments consisting of a WAnT 5 min after either an iTBS or a control treatment. We determined voluntary activation (VA) of the right knee extensors with TMS (VATMS) and with peripheral nerve stimulation (VAPNS) of the femoral nerve, before and after the WAnT. T-tests were applied to the WAnT results and a two way within subject ANOVA was applied to VA results. The iTBS treatment increased the peak power and the maximum pedalling cadence and suppressed the reduction of VATMS following the WAnT compared to the control treatment. No behavioral changes related to fatigue (mean power and fatigue index) were observed. These results indicate for the first time that iTBS could be used as a potential intervention to improve anaerobic performance in a sport specific task.

  6. Intermittent Theta Burst Over M1 May Increase Peak Power of a Wingate Anaerobic Test and Prevent the Reduction of Voluntary Activation Measured with Transcranial Magnetic Stimulation

    PubMed Central

    Giboin, Louis-Solal; Thumm, Patrick; Bertschinger, Raphael; Gruber, Markus

    2016-01-01

    Despite the potential of repetitive transcranial magnetic stimulation (rTMS) to improve performances in patients suffering from motor neuronal afflictions, its effect on motor performance enhancement in healthy subjects during a specific sport task is still unknown. We hypothesized that after an intermittent theta burst (iTBS) treatment, performance during the Wingate Anaerobic Test (WAnT) will increase and supraspinal fatigue following the exercise will be lower in comparison to a control treatment. Ten subjects participated in two randomized experiments consisting of a WAnT 5 min after either an iTBS or a control treatment. We determined voluntary activation (VA) of the right knee extensors with TMS (VATMS) and with peripheral nerve stimulation (VAPNS) of the femoral nerve, before and after the WAnT. T-tests were applied to the WAnT results and a two way within subject ANOVA was applied to VA results. The iTBS treatment increased the peak power and the maximum pedalling cadence and suppressed the reduction of VATMS following the WAnT compared to the control treatment. No behavioral changes related to fatigue (mean power and fatigue index) were observed. These results indicate for the first time that iTBS could be used as a potential intervention to improve anaerobic performance in a sport specific task. PMID:27486391

  7. Statistical Properties of SGR 1900+14 Bursts

    NASA Technical Reports Server (NTRS)

    Gogus, Ersin; Woods, Peter M.; Kouveliotou, Chryssa; vanParadijs, Jan; Briggs, Michael S.; Duncan, Robert C.; Thompson, Christopher

    1999-01-01

    We study the statistics of soft gamma repeater (SGR) bursts, using a data base of 187 events detected with BATSE and 837 events detected with RXTE PCA, all from SGR 1900+14 during its 1998-1999 active phase. we find that the fluence or energy distribution of bursts is consistent with a power law of index 1.66, over 4 orders of magnitude. This scale-free distribution resembles the Gutenberg-Richter Law for earthquakes, and gives evidence for self-organized criticality in SGRS. The distribution of time intervals between successive bursts from SGR 1900+14 is consistent with a log-normal distribution. There is no correlation between burst intensity and the waiting times till the next burst, but there is some evidence for a correlation between burst intensity and the time elapsed since the previous burst. We also find a correlation between the duration and the energy of the bursts, but with significant scatter. In all these statistical properties, SGR bursts resemble earthquakes and solar flares more closely than they resemble any known accretion-powered or nuclear-powered phenomena. Thus our analysis lends support to the hypothesis that the energy source for SGR bursts is internal to the neutron star, and plausibly magnetic.

  8. Statistical Properties of SGR 1900+14 Bursts

    NASA Technical Reports Server (NTRS)

    Gogus, Ersin; Woods, Peter M.; Kouveliotou, Chryssa; VanParadijs, Jan

    1999-01-01

    We study the statistics of soft gamma repeater (SGR) bursts using a database of 187 events detected with BATSE and 837 events detected with the Rossi X-Ray Timing Explorer Proportional Counter Array: all events are from SGR 1900+14 during its 1998-1999 active phase. We find that the fluence or energy distribution of bursts is consistent with a power law of index 1.66, over 4 orders of magnitude. This scale-free distribution resembles the Gutenberg-Richter law for earthquakes and gives evidence for self-organized criticality in SGRS. The distribution of time intervals between successive bursts from SGR 1900+14 is consistent with a lognormal distribution. There is no correlation between burst intensity and the waiting times till the next burst, but there is some evidence for a correlation between burst intensity and the time elapsed since the previous burst. We also find a correlation between the duration and the energy of the bursts, but with significant scatter. In all these statistical properties, SGR bursts resemble earthquakes and solar flares more closely than they resemble any known accretion-powered or nuclear-powered phenomena. Thus, our analysis lends support to the hypothesis that the energy source for SGR bursts is internal to the neutron star and plausibly magnetic.

  9. PKCepsilon activation augments cardiac mitochondrial respiratory post-anoxic reserve--a putative mechanism in PKCepsilon cardioprotection.

    PubMed

    McCarthy, Joy; McLeod, Christopher J; Minners, Jan; Essop, M Faadiel; Ping, Peipei; Sack, Michael N

    2005-04-01

    Modest cardiac-overexpression of constitutively active PKCepsilon (aPKCepsilon) in transgenic mice evokes cardioprotection against ischemia. As aPKCepsilon interacts with mitochondrial respiratory-chain proteins we hypothesized that aPKCepsilon modulates respiration to induce cardioprotection. Using isolated cardiac mitochondria wild-type and aPKCepsilon mice display similar basal mitochondrial respiration, rate of ATP synthesis and adenosine nucleotide translocase (ANT) functional content. Conversely, the aPKCepsilon mitochondria exhibit modest hyperpolarization of their inner mitochondrial membrane potential (DeltaPsi(m)) compared to wild-type mitochondrial by flow cytometry. To assess whether this hyperpolarization engenders resilience to simulated ischemia, anoxia-reoxygenation experiments were performed. Mitochondria were exposed to 45 min anoxia followed by reoxygenation. At reoxygenation, aPKCepsilon mitochondria recovered ADP-dependent respiration to 44 +/- 3% of baseline compared to 28 +/- 2% in WT controls (P = 0.03) in parallel with enhanced ATP synthesis. This preservation in oxidative phosphorylation is coupled to greater ANT functional content [42% > concentration of atractyloside for inhibition in the aPKCepsilon mitochondria vs. WT control (P < 0.0001)], retention of mitochondrial cytochrome c and conservation of DeltaPsi(m). These data demonstrate that mitochondria from PKCepsilon activated mice are intrinsically resilient to anoxia-reoxygenation compared to WT controls. This resilience is in part due to enhanced recovery of oxidative phosphorylation coupled to maintained ANT activity. As maintenance of ATP is a prerequisite for cellular viability we conclude that PKCepsilon activation augmented mitochondrial respiratory capacity in response to anoxia-reoxygenation may contribute to the PKCepsilon cardioprotective program.

  10. A Burst to See

    NASA Astrophysics Data System (ADS)

    2008-04-01

    On 19 March, Nature was particularly generous and provided astronomers with the wealth of four gamma-ray bursts on the same day. But that was not all: one of them is the most luminous object ever observed in the Universe. Despite being located in a distant galaxy, billions of light years away, it was so bright that it could have been seen, for a brief while, with the unaided eye. ESO PR Photo 08a/08 ESO PR Photo 08a/08 The REM Telescope and TORTORA Camera Gamma-ray bursts (GRBs) are short flashes of energetic gamma-rays lasting from less than a second to several minutes. They release a tremendous quantity of energy in this short time making them the most powerful events since the Big Bang. It is now widely accepted that the majority of the gamma-ray bursts signal the explosion of very massive, highly evolved stars that collapse into black holes. Gamma-ray bursts, which are invisible to our eyes, are discovered by telescopes in space. After releasing their intense burst of high-energy radiation, they become detectable for a short while in the optical and in the near-infrared. This 'afterglow' fades very rapidly, making detailed analysis possible for only a few hours after the gamma-ray detection. This analysis is important in particular in order to determine the GRB's distance and, hence, intrinsic brightness. The gamma-ray burst GRB 080319B was detected by the NASA/STFC/ASI Swift satellite. "It was so bright that it almost blinded the Swift instruments for a while," says Guido Chincarini, Italian principal investigator of the mission. A bright optical counterpart was soon identified in the Boötes Constellation (the "Bear Driver" or "Herdsman"). A host of ground-based telescopes reacted promptly to study this new object in the sky. In particular, the optical emission was detected by a few wide-field cameras on telescopes that constantly monitor a large fraction of the sky, including the TORTORA camera in symbiosis with the 0.6-m REM telescope located at La Silla

  11. Fast Radio Bursts

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria M.

    2017-01-01

    Fast Radio Bursts (FRBs) are a recently discovered phenomenon consisting of short (few ms) bursts of radio waves that have dispersion measures that strongly suggest an extragalactic and possibly cosmological origin. Current best estimates for the rate of FRBs is several thousand per sky per day at radio frequencies near 1.4 GHz. Even with so high a rate, to date, fewer than 20 FRBs have been reported, with one source showing repeated bursts. In this talk I will describe known FRB properties including what is known about the lone repeating source, as well as models for the origin of these mysterious events. I will also describe the CHIME radio telescope, currently under construction in Canada. Thanks to its great sensitivity and unprecedented field-of-view, CHIME promises major progress on FRBs.

  12. Evaluation of endotoxin (LPS) activity in bovine blood using neutrophil dependent chemiluminescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to evaluate the applicability of a neutrophil chemiluminescence-based assay for the measurement of LPS stimulatory activity in bovine whole blood. The assay is based on the capacity for LPS to trigger the respiratory oxidative burst activity (RBA) of autologous neutroph...

  13. Characterizing Oscillatory Bursts in Single-Trial EEG Data

    NASA Technical Reports Server (NTRS)

    Knuth, K. H.; Shah, A. S.; Lakatos, P.; Schroeder, C. E.

    2004-01-01

    Oscillatory bursts in numerous bands ranging from low (theta) to high frequencies (e.g., gamma) undoubtedly play an important role in cortical dynamics. Largely because of the inadequacy of existing analytic techniques. however, oscillatory bursts and their role in cortical processing remains poorly understood. To study oscillatory bursts effectively one must be able to isolate them and characterize them in the single trial. We describe a series of straightforward analysis techniques that produce useful indices of burst characteristics. First, stimulus-evoked responses are estimated using Differentially Variable Component Analysis (dVCA), and are subtracted from the single-trial. The single-trial characteristics of the evoked responses are stored to identify possible correlations with burst activity. Time-frequency (T-F), or wavelet, analyses are then applied to the single trial residuals. While T-F plots have been used in recent studies to identify and isolate bursts, we go further by fitting each burst in the T-F plot with a two-dimensional Gaussian. This provides a set of burst characteristics, such as, center time. burst duration, center frequency. frequency dispersion. and amplitude, all of which contribute to the accurate characterization of the individual burst. The burst phase can also be estimated. Burst characteristics can be quantified with several standard techniques (e.g.. histogramming and clustering), as well as Bayesian techniques (e.g., blocking) to allow a more parametric description analysis of the characteristics of oscillatory bursts, and the relationships of specific parameters to cortical excitability and stimulus integration.

  14. The Glast Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles

    2000-01-01

    The Gamma-Ray Large Area Space Telescope (GLAST) will include a secondary instrument to augment the observatory's capabilities for GRB studies. The GLAST Burst Monitor (GBK is a collaboration between Marshall Space Flight Center, the University of Huntsville, Alabama, and the Max Plank Institute for Extraterrestrial Physics. The purpose of the GBM is to extend energy coverage below the main instrument's lower limit of about 20 MeV, and to provide an on-board burst trigger and approximate location. The instrument consists of twelve NaI detectors and two BGO detectors. This combination provides energy coverage from a few keV up to about 30 MeV.

  15. Interplanetary Type IV Bursts

    NASA Astrophysics Data System (ADS)

    Hillaris, A.; Bouratzis, C.; Nindos, A.

    2016-08-01

    We study the characteristics of moving type IV radio bursts that extend to hectometric wavelengths (interplanetary type IV or type {IV}_{{IP}} bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz - 20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraso, and the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay Radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs, and SXR flares. The majority of the events (45) were characterized as compact, their duration was on average 106 minutes. This type of events was, mostly, associated with M- and X-class flares (40 out of 45) and fast CMEs, 32 of these events had CMEs faster than 1000 km s^{-1}. Furthermore, in 43 compact events the CME was possibly subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long-lived type {IV}_{{IP}} bursts was detected, with durations from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal

  16. Absence of detectable influenza RNA transmitted via aerosol during various human respiratory activities--experiments from Singapore and Hong Kong.

    PubMed

    Tang, Julian W; Gao, Caroline X; Cowling, Benjamin J; Koh, Gerald C; Chu, Daniel; Heilbronn, Cherie; Lloyd, Belinda; Pantelic, Jovan; Nicolle, Andre D; Klettner, Christian A; Peiris, J S Malik; Sekhar, Chandra; Cheong, David K W; Tham, Kwok Wai; Koay, Evelyn S C; Tsui, Wendy; Kwong, Alfred; Chan, Kitty; Li, Yuguo

    2014-01-01

    Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cough, from 0.1 m and 0.5 m distance, onto a mouth-breathing manikin. Aerosolised droplets exhaled from the volunteers and entering the manikin's mouth were collected with PTFE filters and an aerosol sampler, in separate experiments. Virus detection was performed using an in-house influenza RNA reverse-transcription polymerase chain reaction (RT-PCR) assay. No influenza RNA was detected from any of the PTFE filters or air samples. For the Singapore experiments, 6 influenza-infected volunteers were asked to breathe (nasal/mouth breathing), talk (counting in English/second language), cough (from 1 m/0.1 m away) and laugh, onto a thermal, breathing manikin. The manikin's face was swabbed at specific points (around both eyes, the nostrils and the mouth) before and after exposure to each of these respiratory activities, and was cleaned between each activity with medical grade alcohol swabs. Shadowgraph imaging was used to record the generation of these respiratory aerosols from the infected volunteers and their impact onto the target manikin. No influenza RNA was detected from any of these swabs with either team's in-house diagnostic influenza assays. All the influenza-infected volunteers had diagnostic swabs taken at recruitment that confirmed influenza (A/H1, A/H3 or B) infection with high viral loads, ranging from 10(5)-10(8) copies/mL (Hong Kong volunteers/assay) and 10(4)-10(7) copies/mL influenza viral RNA (Singapore volunteers/assay). These findings suggest that influenza RNA may not be readily transmitted from naturally-infected human source to susceptible recipients via these natural respiratory activities, within these

  17. Other Community Respiratory Viruses.

    PubMed

    Wunderink, Richard G

    2017-03-01

    Polymerase chain reaction-based diagnosis has become the standard for viral pneumonia and other respiratory tract infections. Expansion of respiratory viral panels (RVPs) outside of influenza and, possibly, respiratory syncytial virus has led to the ability to diagnose viral infections for which no approved specific antiviral treatment exists. Careful clinical evaluation of the patient with a positive RVP is, therefore, critical given the limited repertoire of treatments. Generic treatments with intravenous immunoglobulin, ribavirin, and interferons may benefit select severe viral pneumonia patients, whereas cidofovir has activity for severe adenoviral pneumonia.

  18. Short-burst oxygen therapy for COPD patients: a 6-month randomised, controlled study.

    PubMed

    Eaton, T; Fergusson, W; Kolbe, J; Lewis, C A; West, T

    2006-04-01

    Short-burst oxygen therapy (SBOT) remains widely advocated for patients with chronic obstructive pulmonary disease (COPD), despite a lack of supporting evidence. The aim of this randomised, double-blind, placebo-controlled, parallel group study was to determine whether SBOT improves health-related quality of life (HRQL) or reduces acute healthcare utilisation in patients discharged following an acute exacerbation of COPD. Consecutive patients were screened; 78 of 331 were eligible for randomisation to cylinder oxygen, cylinder air or usual care following discharge. Patients were elderly with high acute healthcare utilisation, forced expiratory volume in one second of <1 L and had dyspnoea limiting daily activity but were not hypoxaemic at rest. Over the 6-month study period, there were no significant differences between patient groups in HRQL (Chronic Respiratory Questionnaire (CRQ), 36-item Short-Form Health Survey, Hospital Anxiety and Depression Scale) except for CRQ emotion domain. There were no significant differences in acute healthcare utilisation. Time to readmission was greatest in the usual care group. Cylinder use was high initially, but rapidly fell to very low levels within weeks in both cylinder oxygen and air groups. In conclusion, the availability of short-burst oxygen therapy for chronic obstructive pulmonary disease patients discharged from hospital following an acute exacerbation did not improve health-related quality of life or reduce acute healthcare utilisation. These results provide no support for the widespread use of short-burst oxygen therapy.

  19. Herschel Far-infrared Photometry of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. I. PACS Observations

    NASA Astrophysics Data System (ADS)

    Meléndez, M.; Mushotzky, R. F.; Shimizu, T. T.; Barger, A. J.; Cowie, L. L.

    2014-10-01

    Far-Infrared (FIR) photometry from the Photodetector Array Camera and Spectrometer on the Herschel Space Observatory is presented for 313 nearby, hard X-ray selected galaxies from the 58 month Swift Burst Alert Telescope (BAT) Active Galactic Nuclei catalog. The present data do not distinguish between the FIR luminosity distributions at 70 and 160 μm for Seyfert 1 and Seyfert 2 galaxies. This result suggests that if the FIR emission is from the nuclear obscuring material surrounding the accretion disk, then it emits isotropically, independent of orientation. Alternatively, a significant fraction of the 70 and 160 μm luminosity could be from star formation, independent of active galactic nucleus (AGN) type. Using a non-parametric test for partial correlation with censored data, we find a statistically significant correlation between the AGN intrinsic power (in the 14-195 keV band) and the FIR emission at 70 and 160 μm for Seyfert 1 galaxies. We find no correlation between the 14-195 keV and FIR luminosities in Seyfert 2 galaxies. The observed correlations suggest two possible scenarios: (1) if we assume that the FIR luminosity is a good tracer of star formation, then there is a connection between star formation and the AGN at sub-kiloparsec scales, or (2) dust heated by the AGN has a statistically significant contribution to the FIR emission. Using a Spearman rank-order analysis, the 14-195 keV luminosities for the Seyfert 1 and 2 galaxies are weakly statistically correlated with the F 70/F 160 ratios. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  20. Herschel far-infrared photometry of the swift burst alert telescope active galactic nuclei sample of the local universe. I. PACS observations

    SciTech Connect

    Meléndez, M.; Mushotzky, R. F.; Shimizu, T. T.; Barger, A. J.; Cowie, L. L.

    2014-10-20

    Far-Infrared (FIR) photometry from the Photodetector Array Camera and Spectrometer on the Herschel Space Observatory is presented for 313 nearby, hard X-ray selected galaxies from the 58 month Swift Burst Alert Telescope (BAT) Active Galactic Nuclei catalog. The present data do not distinguish between the FIR luminosity distributions at 70 and 160 μm for Seyfert 1 and Seyfert 2 galaxies. This result suggests that if the FIR emission is from the nuclear obscuring material surrounding the accretion disk, then it emits isotropically, independent of orientation. Alternatively, a significant fraction of the 70 and 160 μm luminosity could be from star formation, independent of active galactic nucleus (AGN) type. Using a non-parametric test for partial correlation with censored data, we find a statistically significant correlation between the AGN intrinsic power (in the 14-195 keV band) and the FIR emission at 70 and 160 μm for Seyfert 1 galaxies. We find no correlation between the 14-195 keV and FIR luminosities in Seyfert 2 galaxies. The observed correlations suggest two possible scenarios: (1) if we assume that the FIR luminosity is a good tracer of star formation, then there is a connection between star formation and the AGN at sub-kiloparsec scales, or (2) dust heated by the AGN has a statistically significant contribution to the FIR emission. Using a Spearman rank-order analysis, the 14-195 keV luminosities for the Seyfert 1 and 2 galaxies are weakly statistically correlated with the F {sub 70}/F {sub 160} ratios.

  1. Abnormal Bursting as a Pathophysiological Mechanism in Parkinson's Disease

    PubMed Central

    Lobb, CJ

    2014-01-01

    Despite remarkable advances in Parkinson's disease (PD) research, the pathophysiological mechanisms causing motor dysfunction remain unclear, possibly delaying the advent of new and improved therapies. Several such mechanisms have been proposed including changes in neuronal firing rates, the emergence of pathological oscillatory activity, increased neural synchronization, and abnormal bursting. This review focuses specifically on the role of abnormal bursting of basal ganglia neurons in PD, where a burst is a physiologically-relevant, transient increase in neuronal firing over some reference period or activity. After reviewing current methods for how bursts are detected and what the functional role of bursts may be under normal conditions, existing studies are reviewed that suggest that bursting is abnormally increased in PD and that this increases with worsening disease. Finally, the influence of therapeutic approaches for PD such as dopamine-replacement therapy with levodopa or dopamine agonists, lesions, or deep brain stimulation on bursting is discussed. Although there is insufficient evidence to conclude that increased bursting causes motor dysfunction in PD, current evidence suggests that targeted investigations into the role of bursting in PD may be warranted. PMID:24729952

  2. Nanoelectropulse intracellular perturbation and electropermeabilization technology: phospholipid translocation, calcium bursts, chromatin rearrangement, cardiomyocyte activation, and tumor cell sensitivity.

    PubMed

    Vernier, P Thomas; Sun, Yinghua; Wang, Jingjing; Thu, Mya Mya; Garon, Edward; Valderrabano, Miguel; Marcu, Laura; Koeffler, H Phillip; Gundersen, Martin A

    2005-01-01

    Nanosecond, megavolt-per-meter pulsed electric fields scramble the asymmetric arrangement of phospholipids in the plasma membrane, release intracellular calcium, trigger cardiomyocyte activity, and induce apoptosis in mammalian cancer cells, without the permeabilizing effects associated with longer, lower-field pulses. Dose dependencies with respect to pulse width, amplitude, and repetition rate, and total pulse count are observed for all of these phenomena. Sensitivities vary among cell types; cells of lymphoid origin growing in suspension are more susceptible to nanoelectropulse exposure than solid tumor lines. Simple electrical models of the cell are useful for first-order explanations, but more sophisticated treatments will be required for analysis and prediction at both biomolecular and tissue levels.

  3. Systematic, active surveillance for Middle East respiratory syndrome coronavirus in camels in Egypt

    PubMed Central

    Ali, Mohamed A; Shehata, Mahmoud M; Gomaa, Mokhtar R; Kandeil, Ahmed; El-Shesheny, Rabeh; Kayed, Ahmed S; El-Taweel, Ahmed N; Atea, Mohamed; Hassan, Nagla; Bagato, Ola; Moatasim, Yassmin; Mahmoud, Sara H; Kutkat, Omnia; Maatouq, Asmaa M; Osman, Ahmed; McKenzie, Pamela P; Webby, Richard J; Kayali, Ghazi

    2017-01-01

    Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe human infections and dromedary camels are considered an intermediary host. The dynamics of natural infection in camels are not well understood. Through systematic surveillance in Egypt, nasal, rectal, milk, urine and serum samples were collected from camels between June 2014 and February 2016. Locations included quarantines, markets, abattoirs, free-roaming herds and farmed breeding herds. The overall seroprevalence was 71% and RNA detection rate was 15%. Imported camels had higher seroprevalence (90% vs 61%) and higher RT-PCR detection rates (21% vs 12%) than locally raised camels. Juveniles had lower seroprevalence than adults (37% vs 82%) but similar RT-PCR detection rates (16% vs 15%). An outbreak in a breeding herd, showed that antibodies rapidly wane, that camels become re-infected, and that outbreaks in a herd are sustained for an extended time. Maternal antibodies titers were very low in calves regardless of the antibody titers of the mothers. Our results support the hypothesis that camels are a reservoir for MERS-CoV and that camel trade is an important route of introducing the virus into importing countries. Findings related to waning antibodies and re-infection have implications for camel vaccine development, disease management and zoonotic threat. PMID:28050021

  4. A continuum model of transcriptional bursting

    PubMed Central

    Corrigan, Adam M; Tunnacliffe, Edward; Cannon, Danielle; Chubb, Jonathan R

    2016-01-01

    Transcription occurs in stochastic bursts. Early models based upon RNA hybridisation studies suggest bursting dynamics arise from alternating inactive and permissive states. Here we investigate bursting mechanism in live cells by quantitative imaging of actin gene transcription, combined with molecular genetics, stochastic simulation and probabilistic modelling. In contrast to early models, our data indicate a continuum of transcriptional states, with a slowly fluctuating initiation rate converting the gene between different levels of activity, interspersed with extended periods of inactivity. We place an upper limit of 40 s on the lifetime of fluctuations in elongation rate, with initiation rate variations persisting an order of magnitude longer. TATA mutations reduce the accessibility of high activity states, leaving the lifetime of on- and off-states unchanged. A continuum or spectrum of gene states potentially enables a wide dynamic range for cell responses to stimuli. DOI: http://dx.doi.org/10.7554/eLife.13051.001 PMID:26896676

  5. Local cortical dynamics of burst suppression in the anaesthetized brain.

    PubMed

    Lewis, Laura D; Ching, Shinung; Weiner, Veronica S; Peterfreund, Robert A; Eskandar, Emad N; Cash, Sydney S; Brown, Emery N; Purdon, Patrick L

    2013-09-01

    Burst suppression is an electroencephalogram pattern that consists of a quasi-periodic alternation between isoelectric 'suppressions' lasting seconds or minutes, and high-voltage 'bursts'. It is characteristic of a profoundly inactivated brain, occurring in conditions including hypothermia, deep general anaesthesia, infant encephalopathy and coma. It is also used in neurology as an electrophysiological endpoint in pharmacologically induced coma for brain protection after traumatic injury and during status epilepticus. Classically, burst suppression has been regarded as a 'global' state with synchronous activity throughout cortex. This assumption has influenced the clinical use of burst suppression as a way to broadly reduce neural activity. However, the extent of spatial homogeneity has not been fully explored due to the challenges in recording from multiple cortical sites simultaneously. The neurophysiological dynamics of large-scale cortical circuits during burst suppression are therefore not well understood. To address this question, we recorded intracranial electrocorticograms from patients who entered burst suppression while receiving propofol general anaesthesia. The electrodes were broadly distributed across cortex, enabling us to examine both the dynamics of burst suppression within local cortical regions and larger-scale network interactions. We found that in contrast to previous characterizations, bursts could be substantially asynchronous across the cortex. Furthermore, the state of burst suppression itself could occur in a limited cortical region while other areas exhibited ongoing continuous activity. In addition, we found a complex temporal structure within bursts, which recapitulated the spectral dynamics of the state preceding burst suppression, and evolved throughout the course of a single burst. Our observations imply that local cortical dynamics are not homogeneous, even during significant brain inactivation. Instead, cortical and, implicitly

  6. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.

    2004-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) observatory, scheduled for launch in 2007, comprises the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM). spectral changes that are known to occur within GRBs. between the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and the Max Planck Institute for Extraterrestrial Physics. It consists of an array of NaI and BGO scintillation detectors operating in the 10 kev to 25 MeV range. The field of view includes the entire unocculted sky when the observatory is pointing close to the zenith. The GBM will enhance LAT observations of GRBs by extending the spectral coverage into the range of current GRB databases, and will provide a trigger for reorienting the spacecraft to observe delayed emission from bursts outside the LAT field of view. GBM is expected to trigger on about 200 bursts per year, and will provide on-board locations of strong bursts accurate to better than 10 degrees.

  7. Respiratory Modulation of Spontaneous Subthreshold Synaptic Activity in Olfactory Bulb Granule Cells Recorded in Awake, Head-Fixed Mice

    PubMed Central

    Youngstrom, Isaac A.

    2015-01-01

    Although the firing patterns of principal neurons in the olfactory bulb are known to be modulated strongly by respiration even under basal conditions, less is known about whether inhibitory local circuit activity in the olfactory bulb (OB) is modulated phasically. The diverse phase preferences of principal neurons in the OB and olfactory cortex that innervate granule cells (GCs) may interfere and prevent robust respiratory coupling, as suggested by recent findings. Using whole-cell recording, we examined the spontaneous, subthreshold membrane potential of GCs in the OBs of awake head-fixed mice. We found that, during periods of basal respiration, the synaptic input to GCs was strongly phase modulated, leading to a phase preference in the average, cycle-normalized membrane potential. Subthreshold phase tuning was heterogeneous in both mitral and tufted cells (MTCs) and GCs but relatively constant within each GC during periods of increased respiratory frequency. The timing of individual EPSPs in GC recordings also was phase modulated with the phase preference imparted by large-amplitude EPSPs, with fast kinetics often matching the phase tuning of the average membrane potential. These results suggest that activity in a subset of excitatory afferents to GCs, presumably including cortical feedback projections and other sources of large-amplitude unitary EPSPs, function to provide a timing signal linked to respiration. The phase preference we find in the membrane potential may provide a mechanism to dynamically modulate recurrent and lateral dendrodendritic inhibition of MTCs and to selective engage a subpopulation of interneurons based on the alignment of their phase tuning relative to sensory-driven MTC discharges. PMID:26063910

  8. Aspirin activation of eosinophils and mast cells: implications in the pathogenesis of aspirin-exacerbated respiratory disease.

    PubMed

    Steinke, John W; Negri, Julie; Liu, Lixia; Payne, Spencer C; Borish, Larry

    2014-07-01

    Reactions to aspirin and nonsteroidal anti-inflammatory drugs in patients with aspirin-exacerbated respiratory disease (AERD) are triggered when constraints upon activated eosinophils, normally supplied by PGE2, are removed secondary to cyclooxygenase-1 inhibition. However, the mechanism driving the concomitant cellular activation is unknown. We investigated the capacity of aspirin itself to provide this activation signal. Eosinophils were enriched from peripheral blood samples and activated with lysine ASA (LysASA). Parallel samples were stimulated with related nonsteroidal anti-inflammatory drugs. Activation was evaluated as Ca2+ flux, secretion of cysteinyl leukotrienes (CysLT), and eosinophil-derived neurotoxin (EDN) release. CD34+ progenitor-derived mast cells were also used to test the influence of aspirin on human mast cells with measurements of Ca2+ flux and PGD2 release. LysASA induced Ca2+ fluxes and EDN release, but not CysLT secretion from circulating eosinophils. There was no difference in the sensitivity or extent of activation between AERD and control subjects, and sodium salicylate was without effect. Like eosinophils, aspirin was able to activate human mast cells directly through Ca2+ flux and PGD2 release. AERD is associated with eosinophils maturing locally in a high IFN-γ milieu. As such, in additional studies, eosinophil progenitors were differentiated in the presence of IFN-γ prior to activation with aspirin. Eosinophils matured in the presence of IFN-γ displayed robust secretion of both EDN and CysLTs. These studies identify aspirin as the trigger of eosinophil and mast cell activation in AERD, acting in synergy with its ability to release cells from the anti-inflammatory constraints of PGE2.

  9. The correlation between the gamma-ray flashes and electron bursts associated with thunderstorm activity in the near-Earth space

    NASA Astrophysics Data System (ADS)

    Savushkina, L. V.; Aleksandrin, S. Yu; Galper, A. M.; Koldashov, S. V.

    2017-01-01

    This paper is dedicated to study of the interrelation between gamma-ray flashes of atmospheric origin, associated with lightning discharges, and high-energy electron bursts registered in the near-Earth space below the radiation belt. The database of high-energy electron bursts in the energy range of 3-30 MeV obtained in ARINA and VSPLESK satellite experiments and the database of terrestrial gamma-ray flashes with energies up to 17 MeV registered by the NASA RHESSI satellite are used in the work. The results of the analysis of electron bursts and gamma ray flashes that coincide in time and located at the same L-shell are presented at this work.

  10. Effects of ambient ozone on respiratory function in active, normal children

    SciTech Connect

    Spektor, D.M.; Lippmann, M.; Lioy, P.J.; Thurston, G.D.; Citak, K.; James, D.J.; Bock, N.; Speizer, F.E.; Hayes, C.

    1988-02-01

    Respiratory functions were measured on a daily basis by spirometry over a period of 4 wk at a summer camp at Fairview Lake in northwestern New Jersey. Fifty-three boys and 38 girls 8 to 15 yr of age participated in the study on at least 7 days; 37 children were in residence for 4 wk, 34 for the first 2 wk only; and 20 for the last 2 wk. There were 72 whites, 15 blacks, 3 Asians, and 1 Hispanic in the study group. Multiple regression analyses indicated that the O/sub 3/ concentration in the previous hour, the cumulative daily O/sub 3/ exposure during the hours between 9 A.M. and the function measurement, ambient temperature, and humidity were the most explanatory environmental variables for daily variations in function, with the 1 - h O/sub 3/ concentration having the strongest influence. Linear regressions were performed for each child between O/sub 3/ concentration and function, and all average slopes were significantly negative (p less than 0.05) for FVC, FEV1, PEFR, and FEF25-75 for all children, and for boys and girls separately. Comparable results were obtained in data subsets (i.e., children studied during the first or second 2 wk only, and for data sets truncated at O/sub 3/ less than 80 and O/sub 3/ less than 60 ppb). The average regression slopes (+/- SE) for FVC and FEV1, respectively, were -1.03 +/- 0.24 and -1.42 +/- 0.17 ml/ppb, whereas for PEFR and FEF25-75 they were -6.78 +/- 0.73 and -2.48 +/- 0.26 ml/s/ppb.

  11. [Impacts of root-zone hypoxia stress on muskmelon growth, its root respiratory metabolism, and antioxidative enzyme activities].

    PubMed

    Liu, Yi-Ling; Li, Tian-Lai; Sun, Zhou-Ping; Chen, Ya-Dong

    2010-06-01

    By using aeroponics culture system, this paper studied the impacts of root-zone hypoxia (10% O2 and 5% O2) stress on the plant growth, root respiratory metabolism, and antioxidative enzyme activities of muskmelon at its fruit development stage. Root-zone hypoxia stress inhibited the plant growth of muskmelon, resulting in the decrease of plant height, root length, and fresh and dry biomass. Comparing with the control (21% O2), hypoxia stress reduced the root respiration rate and malate dehydrogenase (MDH) activity significantly, and the impact of 5% O2 stress was more serious than that of 10% O2 stress. Under hypoxic conditions, the lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and the malondialdehyde (MDA) content were significantly higher than the control. The increment of antioxidative enzyme activities under 10% O2 stress was significantly higher than that under 5% O2 stress, while the MDA content was higher under 5% O2 stress than under 10% O2 stress, suggesting that when the root-zone oxygen concentration was below 10%, the aerobic respiration of muskmelon at its fruit development stage was obviously inhibited while the anaerobic respiration was accelerated, and the root antioxidative enzymes induced defense reaction. With the increasing duration of hypoxic stress, the lipid peroxidation would be aggravated, resulting in the damages on muskmelon roots, inhibition of plant growth, and decrease of fruit yield and quality.

  12. Study On Burst Location Technology under Steady-state in Water Distribution System

    NASA Astrophysics Data System (ADS)

    Liu, Xianpin; Li, Shuping; Wang, Shaowei; He, Fang; He, Zhixun; Cao, Guodong

    2010-11-01

    According to the characteristics of hydraulic information under the state of burst in water distribution system, to get the correlation of monitoring values and burst location and locate the position of burst on time by mathematical fitting. This method can effectively make use of the information of SCADA in water distribution system to active locating burst position. A new idea of burst location in water distribution systems to shorten the burst time, reduce the impact on urban water supply, economic losses and waste of water resources.

  13. Organotypic slice cultures containing the preBötzinger complex generate respiratory-like rhythms

    PubMed Central

    Phillips, Wiktor S.; Herly, Mikkel; Del Negro, Christopher A.

    2015-01-01

    Study of acute brain stem slice preparations in vitro has advanced our understanding of the cellular and synaptic mechanisms of respiratory rhythm generation, but their inherent limitations preclude long-term manipulation and recording experiments. In the current study, we have developed an organotypic slice culture preparation containing the preBötzinger complex (preBötC), the core inspiratory rhythm generator of the ventrolateral brain stem. We measured bilateral synchronous network oscillations, using calcium-sensitive fluorescent dyes, in both ventrolateral (presumably the preBötC) and dorsomedial regions of slice cultures at 7–43 days in vitro. These calcium oscillations appear to be driven by periodic bursts of inspiratory neuronal activity, because whole cell recordings from ventrolateral neurons in culture revealed inspiratory-like drive potentials, and no oscillatory activity was detected from glial fibrillary associated protein-expressing astrocytes in cultures. Acute slices showed a burst frequency of 10.9 ± 4.2 bursts/min, which was not different from that of brain stem slice cultures (13.7 ± 10.6 bursts/min). However, slice cocultures that include two cerebellar explants placed along the dorsolateral border of the brainstem displayed up to 193% faster burst frequency (22.4 ± 8.3 bursts/min) and higher signal amplitude (340%) compared with acute slices. We conclude that preBötC-containing slice cultures retain inspiratory-like rhythmic function and therefore may facilitate lines of experimentation that involve extended incubation (e.g., genetic transfection or chronic drug exposure) while simultaneously being amenable to imaging and electrophysiology at cellular, synaptic, and network levels. PMID:26655824

  14. RADIATION MECHANISM AND JET COMPOSITION OF GAMMA-RAY BURSTS AND GeV-TeV-SELECTED RADIO-LOUD ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Zhang Jin; Lu Ye; Zhang Shuangnan; Liang Enwei; Sun Xiaona; Zhang Bing

    2013-09-01

    Gamma-ray bursts (GRBs) and GeV-TeV-selected radio-loud active galactic nuclei (AGNs) are compared based on our systematic modeling of the observed spectral energy distributions of a sample of AGNs with a single-zone leptonic model. We show that the correlation between the jet power (P{sub jet}) and the prompt gamma-ray luminosity (L{sub jet}) of GRBs is consistent, within the uncertainties, with the correlation between jet power and the synchrotron peak luminosity (L{sub s,jet}) of flat spectrum radio quasars (FSRQs). Their radiation efficiencies ({epsilon}) are also comparable (>10% for most sources), which increase with the bolometric jet luminosity (L{sub bol,jet}) for FSRQs and with the L{sub jet} for GRBs with similar power-law indices. BL Lac objects (BL Lacs) do not follow the P{sub jet}-L{sub s,jet} relation of FSRQs. They have lower {epsilon} and L{sub bol,jet} values than FSRQs, and a tentative L{sub bol,jet}-{epsilon} relation is also found, with a power-law index different from that of the FSRQs. The magnetization parameters ({sigma}) of FSRQs are on average larger than that of BL Lacs. They are anti-correlated with {epsilon} for the FSRQs, but positively correlated with {epsilon} for the BL Lacs. GeV narrow-line Seyfert 1 galaxies potentially share similar properties with FSRQs. Based on the analogy between GRBs and FSRQs, we suggest that the prompt gamma-ray emission of GRBs is likely produced by the synchrotron process in a magnetized jet with high radiation efficiency, similar to FSRQs. The jets of BL Lacs, on the other hand, are less efficient and are likely more matter-dominated.

  15. Upconversion nanoparticle-mediated photodynamic therapy induces THP-1 macrophage apoptosis via ROS bursts and activation of the mitochondrial caspase pathway

    PubMed Central

    Zhu, Xing; Wang, Hao; Zheng, Longbin; Zhong, Zhaoyu; Li, Xuesong; Zhao, Jing; Kou, Jiayuan; Jiang, Yueqing; Zheng, Xiufeng; Liu, Zhongni; Li, Hongxia; Cao, Wenwu; Tian, Ye; Wang, You; Yang, Liming

    2015-01-01

    Atherosclerosis (AS) is the most vital cardiovascular disease, which poses a great threat to human health. Macrophages play an important role in the progression of AS. Photodynamic therapy (PDT) has emerged as a useful therapeutic modality not only in the treatment of cancer but also in the treatment of AS. The purpose of this study was to determine the molecular mechanisms underlying the activity of PDT, using mesoporous-silica-coated upconversion fluorescent nanoparticles encapsulating chlorin e6 (UCNPs-Ce6) in the induction of apoptosis in THP-1 macrophages. Here, we investigated the ability of UCNPs-Ce6-mediated PDT to induce THP-1 macrophage apoptosis by facilitating the induction of reactive oxygen species (ROS) and regulation of mitochondrial permeability transition pore (MPTP) to depolarize mitochondrial membrane potential (MMP). Both Bax translocation and the release of cytochrome C were examined using immunofluorescence and Western blotting. Our results indicated that the levels of ROS were significantly increased in the PDT group, resulting in both MPTP opening and MMP depolarization, which led to apoptosis. In addition, immunofluorescence and Western blotting revealed that PDT induced both Bax translocation and the release of cytochrome C, as well as upregulation of cleaved caspase-9, cleaved caspase-3, and cleaved poly(ADP-ribose) polymerase. Therefore, we demonstrated that UCNPs-Ce6-mediated PDT induces apoptosis in THP-1 macrophages via ROS bursts. The proapoptotic factor Bax subsequently translocates from the cytosol to the mitochondria, resulting in the MPTP opening and cytochrome C release. This study demonstrated the great potential of UCNPs-Ce6-mediated PDT in the treatment of AS. PMID:26045663

  16. RELATIONSHIP BETWEEN THE KINETIC POWER AND BOLOMETRIC LUMINOSITY OF JETS: LIMITATION FROM BLACK HOLE X-RAY BINARIES, ACTIVE GALACTIC NUCLEI, AND GAMMA-RAY BURSTS

    SciTech Connect

    Ma, Renyi; Hou, Shujin; Xie, Fu-Guo E-mail: fgxie@shao.ac.cn

    2014-01-01

    The correlation between the kinetic power P {sub jet} and intrinsic bolometric luminosity L {sub jet} of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al., we re-investigate this correlation with additional sources of black hole X-ray binaries (BXBs) in hard/quiescent states and low-luminosity active galactic nuclei (LLAGNs). The new sample includes 29 sets of data from 7 BXBs and 20 LLAGNs, with P {sub jet} and L {sub jet} being derived from spectral modeling of the quasi-simultaneous multi-band spectra under the accretion jet scenario. Compared to previous works, the range of luminosity is now enlarged to more than 20 decades, i.e., from ∼10{sup 31} erg s{sup –1} to ∼10{sup 52} erg s{sup –1}, which allows for better constraining of the correlation. One notable result is that the jets in BXBs and LLAGNs almost follow the same P {sub jet}-L {sub jet} correlation that was obtained from blazars and gamma-ray bursts. The slope indices we derived are 1.03 ± 0.01 for the whole sample, 0.85 ± 0.06 for the BXB subsample, 0.71 ± 0.11 for the LLAGN subsample, and 1.01 ± 0.05 for the LLAGN-blazar subsample, respectively. The correlation index around unit implies the independence of jet efficiency on the luminosity or kinetic power. Our results may further support the hypothesis that similar physical processes exist in the jets of various black hole systems.

  17. Herschel far-infrared photometry of the Swift Burst Alert Telescope active galactic nuclei sample of the local universe - II. SPIRE observations

    NASA Astrophysics Data System (ADS)

    Shimizu, T. Taro; Meléndez, Marcio; Mushotzky, Richard F.; Koss, Michael J.; Barger, Amy J.; Cowie, Lennox L.

    2016-03-01

    We present far-infrared (FIR) and submillimetre photometry from the Herschel Space Observatory's Spectral and Photometric Imaging Receiver (SPIRE) for 313 nearby (z < 0.05) active galactic nuclei (AGN). We selected AGN from the 58 month Swift Burst Alert Telescope (BAT) catalogue, the result of an all-sky survey in the 14-195 keV energy band, allowing for a reduction in AGN selection effects due to obscuration and host galaxy contamination. We find 46 per cent (143/313) of our sample is detected at all three wavebands and combined with our Photoconductor Array Camera and Spectrometer (PACS) observations represents the most complete FIR spectral energy distributions of local, moderate-luminosity AGN. We find no correlation among the 250, 350, and 500 μm luminosities with 14-195 keV luminosity, indicating the bulk of the FIR emission is not related to the AGN. However, Seyfert 1s do show a very weak correlation with X-ray luminosity compared to Seyfert 2s and we discuss possible explanations. We compare the SPIRE colours (F250/F350 and F350/F500) to a sample of normal star-forming galaxies, finding the two samples are statistically similar, especially after matching in stellar mass. But a colour-colour plot reveals a fraction of the Herschel-BAT AGN are displaced from the normal star-forming galaxies due to excess 500 μm emission (E500). Our analysis shows E500 is strongly correlated with the 14-195 keV luminosity and 3.4/4.6 μm flux ratio, evidence the excess is related to the AGN. We speculate these sources are experiencing millimetre excess emission originating in the corona of the accretion disc.

  18. Leader neurons in population bursts of 2D living neural networks

    NASA Astrophysics Data System (ADS)

    Eckmann, J.-P.; Jacobi, Shimshon; Marom, Shimon; Moses, Elisha; Zbinden, Cyrille

    2008-01-01

    Eytan and Marom (2006 J. Neurosci. 26 8465-76) recently showed that the spontaneous bursting activity of rat neuron cultures includes 'first-to-fire' cells that consistently fire earlier than others. Here, we analyze the behavior of these neurons in long-term recordings of spontaneous activity of rat hippocampal and rat cortical neuron cultures from three different laboratories. We identify precursor events that may either subside ('aborted bursts') or can lead to a full-blown burst ('pre-bursts'). We find that the activation in the pre-burst typically has a first neuron ('leader'), followed by a localized response in its neighborhood. Locality is diminished in the bursts themselves. The long-term dynamics of the leaders is relatively robust, evolving with a half-life of 23-34 h. Stimulation of the culture alters the leader distribution, but the distribution stabilizes within about 1 h. We show that the leaders carry information about the identity of the burst, as measured by the signature of the number of spikes per neuron in a burst. The number of spikes from leaders in the first few spikes of a precursor event is furthermore shown to be predictive with regard to the transition into a burst (pre-burst versus aborted burst). We conclude that the leaders play a role in the development of the bursts and conjecture that they are part of an underlying sub-network that is excited first and then acts as a nucleation center for the burst.

  19. The Double Firing Burst

    NASA Astrophysics Data System (ADS)

    2008-09-01

    Astronomers from around the world combined data from ground- and space-based telescopes to paint a detailed portrait of the brightest explosion ever seen. The observations reveal that the jets of the gamma-ray burst called GRB 080319B were aimed almost directly at the Earth. Uncovering the disc ESO PR Photo 28/08 A Gamma-Ray Burst with Two Jets Read more on this illuminating blast in the additional story. GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye (ESO 08/08). In a paper to appear in the 11 September issue of Nature, Judith Racusin of Penn State University, Pennsylvania (USA), and a team of 92 co-authors report observations across the electromagnetic spectrum that began 30 minutes before the explosion and followed it for months afterwards. "We conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000," says Guido Chincarini, a member of the team. Gamma-ray bursts are the Universe's most luminous explosions. Most occur when massive stars run out of fuel. As a star collapses, it creates a black hole or neutron star that, through processes not fully understood, drives powerful gas jets outward. As the jets shoot into space, they strike gas previously shed by the star and heat it, thereby generating bright afterglows. The team believes the jet directed toward Earth contained an ultra-fast component just 0.4 degrees across (this is slightly smaller than the apparent size of the Full Moon). This jet is contained within another slightly less energetic jet about 20 times wider. The broad component is more typical of other bursts. "Perhaps every gamma-ray burst has a narrow jet, but astronomers miss it most of the time," says team member Stefano Covino. "We happened to view this monster down the barrel of the very narrow and energetic jet, and the chance for

  20. Burst Populations and Detector Sensitivity

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2003-01-01

    The F(sub T) (peak bolometric photon flux) vs. E(sub p) (peak energy) plane is a powerful tool to compare the burst populations detected by different detectors. Detector sensitivity curves in this plane demonstrate which burst populations the detectors will detect. For example, future CZT-based detectors will show the largest increase in sensitivity for soft bursts, and will be particularly well- suited to study X-ray rich bursts and X-ray Flashes. Identical bursts at different redshifts describe a track in the F(sub T)-E(sub p) plane.

  1. A single amino acid deletion in the matrix protein of porcine reproductive and respiratory syndrome virus confers resistance to a polyclonal swine antibody with broadly neutralizing activity.

    PubMed

    Trible, Benjamin R; Popescu, Luca N; Monday, Nicholas; Calvert, Jay G; Rowland, Raymond R R

    2015-06-01

    Assessment of virus neutralization (VN) activity in 176 pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV) identified one pig with broadly neutralizing activity. A Tyr-10 deletion in the matrix protein provided escape from broad neutralization without affecting homologous neutralizing activity. The role of the Tyr-10 deletion was confirmed through an infectious clone with a Tyr-10 deletion. The results demonstrate differences in the properties and specificities of VN responses elicited during PRRSV infection.

  2. [Treatment of cough in respiratory tract infections - the effect of combining the natural active compounds with thymol].

    PubMed

    Schönknecht, Karina; Krauss, Hanna; Jambor, Jerzy; Fal, Andrzej M

    2016-01-01

    Cough is one of the characteristic symptoms of upper respiratory tract infections (URI). Herbal medicines are often used in the treatment of the cough associated with infection and to accelerate recovery or support the immune system. An example of such products are extracts of thyme and primrose, and also their combination with thymol. Thymus vulgaris is a spasmolytic, antimicrobial, anti-inflammatory, immunomodulatory and antioxidant agent. The most important component responsible for the activity of thyme is thymol contained in the volatile thyme oil. Primrose is, most of all, a saponine agent with expectorant and secretolytic activity, showing also spasmolytic, anti-inflammatory and antimicrobial effects. Because of the additive effects of the mentioned extracts and their wide activity profile they are often used as a combination drug. The use of this combination was assessed in the URI with the effects of alleviation of cough and dyspnea, and shortening the length of the disease. The effectiveness of the drug containing the extracts of thyme and primrose with the addition of thymol (Bronchosol®) was comparable to synthetic ambroxol and its safety has been proved. Moreover, the in-vitro antibacterial and antifungal effects of this drug have been evaluated.

  3. An off-line implementation of the stable isotope technique for measurements of alternative respiratory pathway activities.

    PubMed

    Nagel, O W; Waldron, S; Jones, H G

    2001-11-01

    In situ measurements of alternative respiratory pathway activity are needed to provide insight into the energy efficiency of plant metabolism under various conditions in the field. The only reliable method at present to measure alternative oxidase (AOX) activity is through measurement of changes in delta(18)O(O(2)), which to date has only been used in laboratory environments. We have developed a cuvette system to measure partitioning of electrons to AOX that is suitable for off-line use and for field experiments. Plant samples are enclosed in airtight cuvettes and O(2) consumption is monitored. Gas samples from the cuvette are stored in evacuated gas containers until measurement of delta(18)O(O(2)). We have validated this method using differing plant material to assess AOX activity. Fractionation factors were calculated from delta(18)O(O(2)) measurements, which could be measured with an accuracy and precision to 0.1 per thousand and 0.3 per thousand, respectively. Potential sources of error are discussed and quantified. Our method provides results similar to those obtained with laboratory incubations on-line to a mass spectrometer but greatly increases the potential for adoption of the stable isotope method.

  4. The respiratory pattern in Drosophila melanogaster selected for desiccation resistance is not associated with the observed evolution of decreased locomotory activity.

    PubMed

    Williams, Adrienne E; Rose, Michael R; Bradley, Timothy J

    2004-01-01

    We examined spontaneous locomotory behavior and respiratory pattern in replicate outbred populations of Drosophila melanogaster selected for desiccation resistance or starvation resistance, as well as their control and ancestral populations. Use of these populations allows us to compare evolved behavioral changes in response to different stress selections. We also reasoned that previously observed changes in respiratory patterns following selection for increased desiccation resistance might be associated with or even caused by changes in locomotory behavior. We measured spontaneous locomotory behavior using video recordings and a computer-based tracking system while simultaneously measuring patterns of CO(2) release from single fruit flies. Statistically significant differences in behavior were observed to be correlated with selection regime. Reduced levels of spontaneous locomotory activity were observed in moist air in both desiccation- and starvation-selected populations compared with their controls. Interestingly, in dry air, only the desiccation-selected flies continue to show reduced spontaneous locomotory activity. No correlation was found between the level of locomotory activity of individual flies and the respiratory patterns of those flies, indicating that the reduced activity levels that have evolved in these flies did not directly cause the documented changes in their respiratory pattern.

  5. Scaling up strategies of the chronic respiratory disease programme of the European Innovation Partnership on Active and Healthy Ageing (Action Plan B3: Area 5).

    PubMed

    Bousquet, J; Farrell, J; Crooks, G; Hellings, P; Bel, E H; Bewick, M; Chavannes, N H; de Sousa, J Correia; Cruz, A A; Haahtela, T; Joos, G; Khaltaev, N; Malva, J; Muraro, A; Nogues, M; Palkonen, S; Pedersen, S; Robalo-Cordeiro, C; Samolinski, B; Strandberg, T; Valiulis, A; Yorgancioglu, A; Zuberbier, T; Bedbrook, A; Aberer, W; Adachi, M; Agusti, A; Akdis, C A; Akdis, M; Ankri, J; Alonso, A; Annesi-Maesano, I; Ansotegui, I J; Anto, J M; Arnavielhe, S; Arshad, H; Bai, C; Baiardini, I; Bachert, C; Baigenzhin, A K; Barbara, C; Bateman, E D; Beghé, B; Kheder, A Ben; Bennoor, K S; Benson, M; Bergmann, K C; Bieber, T; Bindslev-Jensen, C; Bjermer, L; Blain, H; Blasi, F; Boner, A L; Bonini, M; Bonini, S; Bosnic-Anticevitch, S; Boulet, L P; Bourret, R; Bousquet, P J; Braido, F; Briggs, A H; Brightling, C E; Brozek, J; Buhl, R; Burney, P G; Bush, A; Caballero-Fonseca, F; Caimmi, D; Calderon, M A; Calverley, P M; Camargos, P A M; Canonica, G W; Camuzat, T; Carlsen, K H; Carr, W; Carriazo, A; Casale, T; Cepeda Sarabia, A M; Chatzi, L; Chen, Y Z; Chiron, R; Chkhartishvili, E; Chuchalin, A G; Chung, K F; Ciprandi, G; Cirule, I; Cox, L; Costa, D J; Custovic, A; Dahl, R; Dahlen, S E; Darsow, U; De Carlo, G; De Blay, F; Dedeu, T; Deleanu, D; De Manuel Keenoy, E; Demoly, P; Denburg, J A; Devillier, P; Didier, A; Dinh-Xuan, A T; Djukanovic, R; Dokic, D; Douagui, H; Dray, G; Dubakiene, R; Durham, S R; Dykewicz, M S; El-Gamal, Y; Emuzyte, R; Fabbri, L M; Fletcher, M; Fiocchi, A; Fink Wagner, A; Fonseca, J; Fokkens, W J; Forastiere, F; Frith, P; Gaga, M; Gamkrelidze, A; Garces, J; Garcia-Aymerich, J; Gemicioğlu, B; Gereda, J E; González Diaz, S; Gotua, M; Grisle, I; Grouse, L; Gutter, Z; Guzmán, M A; Heaney, L G; Hellquist-Dahl, B; Henderson, D; Hendry, A; Heinrich, J; Heve, D; Horak, F; Hourihane, J O' B; Howarth, P; Humbert, M; Hyland, M E; Illario, M; Ivancevich, J C; Jardim, J R; Jares, E J; Jeandel, C; Jenkins, C; Johnston, S L; Jonquet, O; Julge, K; Jung, K S; Just, J; Kaidashev, I; Kaitov, M R; Kalayci, O; Kalyoncu, A F; Keil, T; Keith, P K; Klimek, L; Koffi N'Goran, B; Kolek, V; Koppelman, G H; Kowalski, M L; Kull, I; Kuna, P; Kvedariene, V; Lambrecht, B; Lau, S; Larenas-Linnemann, D; Laune, D; Le, L T T; Lieberman, P; Lipworth, B; Li, J; Lodrup Carlsen, K; Louis, R; MacNee, W; Magard, Y; Magnan, A; Mahboub, B; Mair, A; Majer, I; Makela, M J; Manning, P; Mara, S; Marshall, G D; Masjedi, M R; Matignon, P; Maurer, M; Mavale-Manuel, S; Melén, E; Melo-Gomes, E; Meltzer, E O; Menzies-Gow, A; Merk, H; Michel, J P; Miculinic, N; Mihaltan, F; Milenkovic, B; Mohammad, G M Y; Molimard, M; Momas, I; Montilla-Santana, A; Morais-Almeida, M; Morgan, M; Mösges, R; Mullol, J; Nafti, S; Namazova-Baranova, L; Naclerio, R; Neou, A; Neffen, H; Nekam, K; Niggemann, B; Ninot, G; Nyembue, T D; O'Hehir, R E; Ohta, K; Okamoto, Y; Okubo, K; Ouedraogo, S; Paggiaro, P; Pali-Schöll, I; Panzner, P; Papadopoulos, N; Papi, A; Park, H S; Passalacqua, G; Pavord, I; Pawankar, R; Pengelly, R; Pfaar, O; Picard, R; Pigearias, B; Pin, I; Plavec, D; Poethig, D; Pohl, W; Popov, T A; Portejoie, F; Potter, P; Postma, D; Price, D; Rabe, K F; Raciborski, F; Radier Pontal, F; Repka-Ramirez, S; Reitamo, S; Rennard, S; Rodenas, F; Roberts, J; Roca, J; Rodriguez Mañas, L; Rolland, C; Roman Rodriguez, M; Romano, A; Rosado-Pinto, J; Rosario, N; Rosenwasser, L; Rottem, M; Ryan, D; Sanchez-Borges, M; Scadding, G K; Schunemann, H J; Serrano, E; Schmid-Grendelmeier, P; Schulz, H; Sheikh, A; Shields, M; Siafakas, N; Sibille, Y; Similowski, T; Simons, F E R; Sisul, J C; Skrindo, I; Smit, H A; Solé, D; Sooronbaev, T; Spranger, O; Stelmach, R; Sterk, P J; Sunyer, J; Thijs, C; To, T; Todo-Bom, A; Triggiani, M; Valenta, R; Valero, A L; Valia, E; Valovirta, E; Van Ganse, E; van Hage, M; Vandenplas, O; Vasankari, T; Vellas, B; Vestbo, J; Vezzani, G; Vichyanond, P; Viegi, G; Vogelmeier, C; Vontetsianos, T; Wagenmann, M; Wallaert, B; Walker, S; Wang, D Y; Wahn, U; Wickman, M; Williams, D M; Williams, S; Wright, J; Yawn, B P; Yiallouros, P K; Yusuf, O M; Zaidi, A; Zar, H J; Zernotti, M E; Zhang, L; Zhong, N; Zidarn, M; Mercier, J

    2016-01-01

    Action Plan B3 of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) focuses on the integrated care of chronic diseases. Area 5 (Care Pathways) was initiated using chronic respiratory diseases as a model. The chronic respiratory disease action plan includes (1) AIRWAYS integrated care pathways (ICPs), (2) the joint initiative between the Reference site MACVIA-LR (Contre les MAladies Chroniques pour un VIeillissement Actif) and ARIA (Allergic Rhinitis and its Impact on Asthma), (3) Commitments for Action to the European Innovation Partnership on Active and Healthy Ageing and the AIRWAYS ICPs network. It is deployed in collaboration with the World Health Organization Global Alliance against Chronic Respiratory Diseases (GARD). The European Innovation Partnership on Active and Healthy Ageing has proposed a 5-step framework for developing an individual scaling up strategy: (1) what to scale up: (1-a) databases of good practices, (1-b) assessment of viability of the scaling up of good practices, (1-c) classification of good practices for local replication and (2) how to scale up: (2-a) facilitating partnerships for scaling up, (2-b) implementation of key success factors and lessons learnt, including emerging technologies for individualised and predictive medicine. This strategy has already been applied to the chronic respiratory disease action plan of the European Innovation Partnership on Active and Healthy Ageing.

  6. The afferent activity of the superior laryngeal nerve, and respiratory reflexes specifically responding to intralaryngeal pressure changes in anesthetized Shiba goats.

    PubMed

    Sekizawa, S; Tsubone, H; Hishida, N; Kuwahara, M; Sugano, S

    1997-10-01

    This study was aimed at characterizing the superior laryngeal nerve (SLN) afferent activities under four different respiratory conditions, i.e., tracheostomy breathing (TB), upper airway breathing (UAB), tracheal occlusion (TO) and upper airway occlusion (UAO), and investigating respiratory changes in response to transmural pressures applied to the larynx in anesthetized Shiba goats. The activity recorded from the whole SLN increased at both inspiration and expiration during TB, UAB and TO, while an expiratory augmentation accompanied by an inspiratory inhibition was found during UAO. Based on recordings from 109 thin filament-preparations, 47 units were identified as 'drive' receptors, 31 as 'pressure' receptors (22 'positive' and 9 'negative' pressure receptors), and the rest 31 as 'non-modulated type' of receptors. The posterior cricoarytenoid (PCA) muscle activity showed a clear inspiratory modulation during UAB and was significantly enhanced by negative pressure applied to the isolated upper airway, where such an augmented activity was abolished by bilateral section of the SLN. No significant changes were found in the respiratory cycle during application of negative pressures to the larynx. The respiratory modulation of the SLN in Shiba goats was essentially identical to that reported for rabbits, rats and guinea pigs, but not in dogs. The reflex response of the upper airway muscles to the laryngeal pressure changes in Shiba goats were found to be less noticeable than in rabbits and dogs.

  7. A repeating fast radio burst

    NASA Astrophysics Data System (ADS)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  8. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  9. Respiratory Therapists

    MedlinePlus

    ... programs typically include courses in human anatomy and physiology, chemistry, physics, microbiology, pharmacology, and math. Other courses ... and math skills. Respiratory therapists must understand anatomy, physiology, and other sciences and be able to calculate ...

  10. Jovian type III radio bursts

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Gurnett, D. A.; Scarf, F. L.

    1989-01-01

    Radio bursts have been observed in the Voyager plasma wave data from Jupiter that bear a striking resemblance to solar type III radio bursts. The emissions lie in the frequency range near 10 kHz, have durations of a minute or so, and occur in a set of periodically spaced bursts. The spacing between primary bursts is typically 15 min, but the bursts may have additional components which recur on time scales of about 3 min. The similarity with solar type III radio bursts suggests a source mechanism involving the movement of energetic electrons through a density gradient in the plasma surrounding Jupiter. The periodicity of bursts suggests Io may be involved in the generation of waves, since the timing is similar to the Alfven wave travel time from one hemisphere to the other through the Io torus.

  11. [Effect of 2,4-dinitrophenol on the rat liver respiratory activity and ATP content after hypothermic storage and following reperfusion].

    PubMed

    Cherkashyna, D V; Tkachova, O M; Somov, O Iu; Semenchenko, O A; Lebedyns'kyĭ, O S; Petrenko, O Iu

    2008-01-01

    The influence of oxidative phosphorylation uncoupler 2,4-dinitrophenol (DNP) presence in preserving solution on the rat liver respiratory activity and ATP content after 18 h of hypothermic storage (HS) and following normothermic reperfusion (NR) was investigated. DNP presence on the HS stage led to decrease of ATP level as compared with the control. After DNP removal during NR the gradual recovery of oxidative phosphorylation coupling occurred. This fact resulted in improvement of mitochondrial functional state (V4 respiration rate decrease, respiratory control and ATP level increase).

  12. Inflammatory cells and cellular activation in the lower respiratory tract in Churg-Strauss syndrome

    PubMed Central

    Schnabel, A.; Csernok, E.; Braun, J.; Gross, W.

    1999-01-01

    BACKGROUND—To obtain insight into the mechanisms of tissue injury in lung disease due to Churg-Strauss syndrome (CSS), the bronchoalveolar lavage (BAL) cell profile and the levels in the BAL fluid of cell products released by activated eosinophils and neutrophils were assessed.
METHODS—Thirteen patients with active progressive CSS (n = 7) or CSS in partial remission (n = 6) underwent clinical staging and bronchoalveolar lavage. The levels of eosinophil cationic protein (ECP), myeloperoxidase (MPO), and peroxidase activity in the BAL fluid were determined and the results were compared with those of 19 patients with pulmonary active Wegener's granulomatosis (WG) and nine control subjects.
RESULTS—In patients with progressive CSS the BAL cell profile was dominated by eosinophils, neutrophil elevation being the exception. The eosinophilia was associated with high ECP levels (4.39 ng/ml and 0.40 ng/ml in the two CSS groups compared with unmeasurable values in the controls). Individual patients with highly active CSS also had raised MPO levels, comparable to the levels in the most active WG patients. Peroxidase activity in the BAL fluid was 1.26 U/ml and 0.10 U/ml in the two groups of patients with CSS and 0.20 U/ml in the controls. Pulmonary disease in patients with WG was characterised by an extensive increase in MPO (0.30ng/ml versus 0.13 ng/ml in the controls) together with high peroxidase activity in the BAL fluid (4.37 U/ml), but only a small increase in ECP levels was seen. No correlation was found between the ECP and MPO levels in patients with CSS which suggests that eosinophil and neutrophil activation vary independently of each other.
CONCLUSIONS—These findings suggest that, in addition to eosinophil activation, neutrophil activation is an important feature in some patients with highly active CSS. The balance of neutrophil and eosinophil involvement appears to be variable and this may be one explanation for the individually variable treatment

  13. Statistical Properties of SGR J1550-5418 Bursts

    NASA Technical Reports Server (NTRS)

    Gorgone, Nicholas M.

    2010-01-01

    Magnetars are slowly rotating neutron stars with extreme magnetic fields, over 10(exp 15) Gauss. Only few have been discovered in the last 30 years. These sources are dormant most of their lifetimes and become randomly active emitting multiple soft gamma-ray bursts. We present here our results on the temporal analysis of 300 bursts from Soft Gamma Repeater SGR J1550-5418 recorded with the Gamma-ray Burst Monitor (GBM) onboard the Fermi Observatory during its activation on January 22-29, 2009. We employed an un-triggered burst search in the energy range 8-100keV to collect all events from the source, besides the ones that triggered GBM. For the entire sample of bursts we determined their durations, rise and decay times. We study here the statistical properties of these characteristics and discuss how these may help us better understand the physical characteristics of the magnetar model.

  14. [Respiratory distress].

    PubMed

    Galili, D; Garfunkel, A; Elad, S; Zusman, S P; Malamed, S F; Findler, M; Kaufman, E

    2002-01-01

    Dental treatment is usually conducted in the oral cavity and in very close proximity to the upper respiratory airway. The possibility of unintentionally compromising this airway is high in the dental environment. The accumulation of fluid (water or blood) near to the upper respiratory airway or the loosening of teeth fragmentations and fallen dental instruments can occur. Also, some of the drugs prescribed in the dental practice are central nervous system depressants and some are direct respiratory drive depressors. For this reason, awareness of the respiratory status of the dental patient is of paramount importance. This article focuses on several of the more common causes of respiratory distress, including airway obstruction, hyperventilation, asthma, bronchospasm, pulmonary edema, pulmonary embolism and cardiac insufficiency. The common denominator to all these conditions described here is that in most instances the patient is conscious. Therefore, on the one hand, valuable information can be retrieved from the patient making diagnosis easier than when the patient is unconscious. On the other hand, the conscious patient is under extreme apprehension and stress under such situations. Respiratory depression which occurs during conscious sedation or following narcotic analgesic medication will not be dealt with in this article. Advanced pain and anxiety control techniques such as conscious sedation and general anesthesia should be confined only to operators who undergo special extended training.

  15. In vitro activity of five tetracyclines and some other antimicrobial agents against four porcine respiratory tract pathogens.

    PubMed

    Pijpers, A; Van Klingeren, B; Schoevers, E J; Verheijden, J H; Van Miert, A S

    1989-09-01

    The minimal inhibitory concentrations (MIC) of five tetracyclines and ten other antimicrobial agents were determined for four porcine bacterial respiratory tract pathogens by the agar dilution method. For the following oxytetracycline-susceptible strains, the MIC50 ranges of the tetracyclines were: P. multocida (n = 17) 0.25-0.5 micrograms/ml; B. bronchiseptica (n = 20) 0.25-1.0 micrograms/ml; H. pleuropneumoniae (n = 20) 0.25-0.5 micrograms/ml; S. suis Type 2 (n = 20) 0.06-0.25 micrograms/ml. For 19 oxytetracycline-resistant P. multocida strains the MIC50 of the tetracyclines varied from 64 micrograms/ml for oxytetracycline to 0.5 micrograms/ml for minocycline. Strikingly, minocycline showed no cross-resistance with oxytetracycline, tetracycline, chlortetracycline and doxycycline in P. multocida and in H. pleuropneumoniae. Moreover, in susceptible strains minocycline showed the highest in vitro activity followed by doxycycline. Low MIC50 values were observed for chloramphenicol, ampicillin, flumequine, ofloxacin and ciprofloxacin against P. multocida and H. pleuropneumoniae. B. bronchiseptica was moderately susceptible or resistant to these compounds. As expected tiamulin, lincomycin, tylosin and spiramycin were not active against H. pleuropneumoniae. Except for flumequine, the MIC50 values of nine antimicrobial agents were low for S. suis Type 2. Six strains of this species showed resistance to the macrolides and lincomycin.

  16. PADMA-28, a traditional tibetan herbal preparation inhibits the respiratory burst in human neutrophils, the killing of epithelial cells by mixtures of oxidants and pro-inflammatory agonists and peroxidation of lipids.

    PubMed

    Ginsburg, I; Sadovnik, M; Sallon, S; Milo-Goldzweig, I; Mechoulam, R; Breuer, A; Gibbs, D; Varani, J; Roberts, S; Cleator, E; Singh, N

    1999-01-01

    Both aqueous and methanolic fractions derived from the Tibetan preparation PADMA-28 (a mixture of 22 plants) used as an anti-atherosclerotic agent, and which is non-cytolytic to a variety of mammalian cells, were found to strongly inhibit (1) the killing of epithelial cells in culture induced by 'cocktails' comprising oxidants, membrane perforating agents and proteinases; (2) the generation of luminol-dependent chemiluminescence in human neutrophils stimulated by opsonized bacteria; (3) the peroxidation of intralipid (a preparation rich in phopholipids) induced in the presence of copper; and (4) the activity of neutrophil elastase. It is proposed that PADMA-28 might prove beneficial for the prevention of cell damage induced by synergism among pro-inflammatory agonists which is central in the initiation of tissue destruction in inflammatory and infectious conditions.

  17. In Vitro Activity of Solithromycin against Bordetella pertussis, an Emerging Respiratory Pathogen

    PubMed Central

    Vicino, David; Fernandes, Prabhavathi

    2016-01-01

    There has been an increase in the number of pertussis cases reported since the introduction of the acellular pertussis vaccine. While children that present with pertussis have a characteristic whooping cough, adults can simply have a persistent, nonspecific cough and remain undiagnosed. Macrolide antibiotics, such as azithromycin, are the currently recommended treatment for pertussis. Solithromycin is a new macrolide and the first fluoroketolide with broad activity against a wide spectrum of bacterial pathogens and has completed clinical development for community-acquired bacterial pneumonia. This study reports the potent in vitro activity of solithromycin against a collection of recent isolates of Bordetella pertussis. PMID:27620481

  18. Activation of respiratory epithelial cells by wood smoke particles persists beyond immediate exposure.

    EPA Science Inventory

    The biological effect of particles on epithelial cells involves, in part, oxidant generation and a cascade of reactions culminating in inflammatory mediator release. Whether there is an immediate short-lived activation or continued persistent response of the cells to the particle...

  19. Cardiac Mitochondrial Respiratory Dysfunction and Tissue Damage in Chronic Hyperglycemia Correlate with Reduced Aldehyde Dehydrogenase-2 Activity

    PubMed Central

    Deshpande, Mandar; Thandavarayan, Rajarajan A.; Xu, Jiang; Yang, Xiao-Ping; Palaniyandi, Suresh S.

    2016-01-01

    Aldehyde dehydrogenase (ALDH) 2 is a mitochondrial isozyme of the heart involved in the metabolism of toxic aldehydes produced from oxidative stress. We hypothesized that hyperglycemia-mediated decrease in ALDH2 activity may impair mitochondrial respiration and ultimately result in cardiac damage. A single dose (65 mg/kg; i.p.) streptozotocin injection to rats resulted in hyperglycemia with blood glucose levels of 443 ± 9 mg/dl versus 121 ± 7 mg/dl in control animals, p<0.0001, N = 7–11. After 6 months of diabetes mellitus (DM) induction, the rats were sacrificed after recording the functionality of their hearts. Increase in the cardiomyocyte cross sectional area (446 ± 32 μm2 Vs 221 ± 10 μm2; p<0.0001) indicated cardiac hypertrophy in DM rats. Both diastolic and systolic dysfunctions were observed with DM rats compared to controls. Most importantly, myocardial ALDH2 activity and levels were reduced, and immunostaining for 4HNE protein adducts was increased in DM hearts compared to controls. The mitochondrial oxygen consumption rate (OCR), an index of mitochondrial respiration, was decreased in mitochondria isolated from DM hearts compared to controls (p<0.0001). Furthermore, the rate of mitochondrial respiration and the increase in carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP)-induced maximal respiration were also decreased with chronic hyperglycemia. Chronic hyperglycemia reduced mitochondrial OXPHOS proteins. Reduced ALDH2 activity was correlated with mitochondrial dysfunction, pathological remodeling and cardiac dysfunction, respectively. Our results suggest that chronic hyperglycemia reduces ALDH2 activity, leading to mitochondrial respiratory dysfunction and consequently cardiac damage and dysfunction. PMID:27736868

  20. Preserved respiratory and phagocytic functions of phagocytes exposed to flat sheet plasmapheresis equipment.

    PubMed

    Jungi, T W; Aeschbacher, B; Nydegger, U E

    1987-09-01

    Monocytes and polymorphonuclear leukocytes (PMN) were tested for functional integrity after exposure to flat sheet plasmapheresis equipment. Purified PMN were tested for chemiluminescence activity in response to a variety of triggers of the respiratory burst. Monocytes were assessed for their capacity to ingest erythrocytes sensitized with varying amounts of IgG antibodies. Both assays were demonstrated to be sensitive hallmarks of functional modulation. However, no functional differences were noted between phagocytes from blood collected prior to pheresis and those exposed to flat sheet plasmapheresis cylinders. These data suggest that plasmapheresis with the Autopheresis C system does not influence the respiratory and phagocytic function of phagocytes returned back to the donor and implies that contact of phagocytes with artificial surfaces and/or their exposure to surface-activated plasma factors generated in the collection cylinder are minimal when using this plasmapheresis method.

  1. Action potential bursts enhance transmitter release at a giant central synapse.

    PubMed

    Zhang, Bo; Sun, Liang; Yang, Yi-Mei; Huang, Hong-Ping; Zhu, Fei-Peng; Wang, Li; Zhang, Xiao-Yu; Guo, Shu; Zuo, Pan-Li; Zhang, Claire X; Ding, Jiu-Ping; Wang, Lu-Yang; Zhou, Zhuan

    2011-05-01

    Patterns of action potentials (APs), often in the form of bursts, are critical for coding and processing information in the brain. However, how AP bursts modulate secretion at synapses remains elusive. Here, using the calyx of Held synapse as a model we compared synaptic release evoked by AP patterns with a different number of bursts while the total number of APs and frequency were fixed. The ratio of total release produced by multiple bursts to that by a single burst was defined as 'burst-effect'.We found that four bursts of 25 stimuli at 100 Hz increased the totalcharge of EPSCs to 1.47 ± 0.04 times that by a single burst of 100 stimuli at the same frequency.Blocking AMPA receptor desensitization and saturation did not alter the burst-effect, indicating that it was mainly determined by presynaptic mechanisms. Simultaneous dual recordings of presynaptic membrane capacitance (Cm) and EPSCs revealed a similar burst-effect, being 1.58±0.13by Cm and 1.49±0.05 by EPSCs. Reducing presynapticCa2+ influx by lowering extracellular Ca2+concentration or buffering residual intracellular Ca2+ with EGTA inhibited the burst-effect. We further developed a computational model largely recapitulating the burst-effect and demonstrated that this effect is highly sensitive to dynamic change in availability of the releasable pool of synaptic vesicles during various patterns of activities. Taken together, we conclude that AP bursts modulate synaptic output mainly through intricate interaction between depletion and replenishment of the large releasable pool. This burst-effect differs from the somatic burst-effect previously described from adrenal chromaffin cells, which substantially depends on activity-induced accumulation of Ca2+ to facilitate release of a limited number of vesicles in the releasable pool. Hence, AP bursts may play an important role in dynamically regulating synaptic strength and fidelity during intense neuronal activity at central synapses.

  2. The effects of inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise on chronic stroke patients’ respiratory muscle activation

    PubMed Central

    Seo, KyoChul; Hwan, Park Seung; Park, KwangYong

    2017-01-01

    [Purpose] The purpose of this study is to examine the effects of inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise on chronic stroke patients’ respiratory muscle activation. [Subjects and Methods] All experimental subjects performed exercises five times per week for four weeks. Thirty chronic stroke patients were randomly assign to an experimental group of 15 patients and a control group of 15 patients. The experimental group underwent exercises consisting of basic exercise treatment for 15 minutes and inspiratory diaphragm breathing exercise and expiratory pursed-lip breathing exercise for 15 minutes and the control group underwent exercises consisting of basic exercise treatment for 15 minutes and auto-med exercise for 15 minutes. The activation levels of respiratory muscles were measured before and after the experiment using MP 150WSW to obtain the results of the experiment. [Results] In the present study, when the pulmonary functions of the experimental group and the control group before and after the experiment were compared, whereas the experimental group showed significant differences in all sections. In the verification of intergroup differences between the experimental group and the control group before and after the experiment. [Conclusion] The respiratory rehabilitation exercise is considered to be capable of inducing positive effects on stroke patients’ respiratory muscles through diaphragm breathing exercise and lip puckering breathing exercise. PMID:28356632

  3. High-Frequency Cutoff in Type III Bursts

    NASA Astrophysics Data System (ADS)

    Stanislavsky, A. A.; Konovalenko, A. A.; Volvach, Ya. S.; Koval, A. A.

    In this article we report about a group of solar bursts with high-frequency cutoff, observed on 19 August of 2012 near 8:23 UT, simultaneously by three different radio telescopes: the Ukrainian decameter radio telescope (8-33 MHz), the French Nancay Decametric Array (10-70 MHz) and the Italian San Vito Solar Observatory of RSTN (25-180 MHz). Morphologically the bursts are very similar to the type III bursts. The solar activity is connected with the emergency of a new group of solar spots on the far side of the Sun with respect to observers on Earth. The solar bursts accompany many moderate flares over eastern limb. The refraction of the behind-limb radio bursts towards the Earth is favorable, if CMEs generate low-density cavities in solar corona.

  4. Simultaneous flow cytometric evaluation of phagocytosis and oxidative burst in human polymorphonuclear cells.

    PubMed

    Horvathova, M; Wsolova, L; Jahnova, E

    2005-01-01

    Phagocytosis and oxidative burst (OXIBURST) activity of human polymorphonuclear cells (PMNs) has been simultaneously measured directly in whole blood samples. The ingestion of yeast was assessed by the phagocytosis activity (FA) and phagocytosis index (FI), and the respiratory burst of PMNs was determined as dihydroethidine (DHE) oxidation. We received comparable results in the ingestion of yeast cells by PMNs using either light microscopy (77.31+/-7.56) or flow cytometry detection method (78.26+/-5.14). The significant differences (p<0.05) in FI and OXIBURST activity were find in the patients (2.29+/-0.29 and 14.67+/-3.99, respectively) when compared to healthy donors (1.64+/-0.21 and 32.38+/-14.94, respectively). The two-color flow cytometric procedure permits measurement of two different functions of neutrophils in one step. This flow cytometric procedure is simple, rapid and has the potential to be an alternative assay to test leukocyte function. (Fig. 3, Ref: 30.)

  5. Activation of Akt/FKHR in the medulla oblongata contributes to spontaneous respiratory recovery after incomplete spinal cord injury in adult rats.

    PubMed

    Felix, M S; Bauer, S; Darlot, F; Muscatelli, F; Kastner, A; Gauthier, P; Matarazzo, V

    2014-09-01

    After incomplete spinal cord injury (SCI), patients and animals may exhibit some spontaneous functional recovery which can be partly attributed to remodeling of injured neural circuitry. This post-lesion plasticity implies spinal remodeling but increasing evidences suggest that supraspinal structures contribute also to the functional recovery. Here we tested the hypothesis that partial SCI may activate cell-signaling pathway(s) at the supraspinal level and that this molecular response may contribute to spontaneous recovery. With this aim, we used a rat model of partial cervical hemisection which injures the bulbospinal respiratory tract originating from the medulla oblongata of the brainstem but leads to a time-dependent spontaneous functional recovery of the paralyzed hemidiaphragm. We first demonstrate that after SCI the PI3K/Akt signaling pathway is activated in the medulla oblongata of the brainstem, resulting in an inactivation of its pro-apoptotic downstream target, forkhead transcription factor (FKHR/FOXO1A). Retrograde labeling of medullary premotoneurons including respiratory ones which project to phrenic motoneurons reveals an increased FKHR phosphorylation in their cell bodies together with an unchanged cell number. Medulla infusion of the PI3K inhibitor, LY294002, prevents the SCI-induced Akt and FKHR phosphorylations and activates one of its death-promoting downstream targets, Fas ligand. Quantitative EMG analyses of diaphragmatic contractility demonstrate that the inhibition of medulla PI3K/Akt signaling prevents spontaneous respiratory recovery normally observed after partial cervical SCI. Such inhibition does not however affect either baseline contractile frequency or the ventilatory reactivity under acute respiratory challenge. Together, these findings provide novel evidence of supraspinal cellular contribution to the spontaneous respiratory recovery after partial SCI.

  6. Pressure overload-induced mild cardiac hypertrophy reduces left ventricular transmural differences in mitochondrial respiratory chain activity and increases oxidative stress

    PubMed Central

    Kindo, Michel; Gerelli, Sébastien; Bouitbir, Jamal; Charles, Anne-Laure; Zoll, Joffrey; Hoang Minh, Tam; Monassier, Laurent; Favret, Fabrice; Piquard, François; Geny, Bernard

    2012-01-01

    Objective: Increased mechanical stress and contractility characterizes normal left ventricular (LV) subendocardium (Endo) but whether Endo mitochondrial respiratory chain complex activities is reduced as compared to subepicardium (Epi) and whether pressure overload-induced LV hypertrophy (LVH) might modulate transmural gradients through increased reactive oxygen species (ROS) production is unknown. Methods: LVH was induced by 6 weeks abdominal aortic banding and cardiac structure and function were determined with echocardiography and catheterization in sham-operated and LVH rats (n = 10 for each group). Mitochondrial respiration rates, coupling, content and ROS production were measured in LV Endo and Epi, using saponin-permeabilized fibers, Amplex Red fluorescence and citrate synthase activity. Results: In sham, a transmural respiratory gradient was observed with decreases in endo maximal oxidative capacity (−36.7%, P < 0.01) and complex IV activity (−57.4%, P < 0.05). Mitochondrial hydrogen peroxide (H2O2) production was similar in both LV layers. Aortic banding induced mild LVH (+31.7% LV mass), associated with normal LV fractional shortening and end diastolic pressure. LVH reduced maximal oxidative capacity (−23.6 and −33.3%), increased mitochondrial H2O2 production (+86.9 and +73.1%), free radical leak (+27.2% and +36.3%) and citrate synthase activity (+27.2% and +36.3%) in Endo and Epi, respectively. Transmural mitochondrial respiratory chain complex IV activity was reduced in LVH (−57.4 vs. −12.2%; P = 0.02). Conclusions: Endo mitochondrial respiratory chain complexes activities are reduced compared to LV Epi. Mild LVH impairs mitochondrial oxidative capacity, increases oxidative stress and reduces transmural complex IV activity. Further studies will be helpful to determine whether reduced LV transmural gradient in mitochondrial respiration might be a new marker of a transition from uncomplicated toward complicated LVH. PMID:22934079

  7. CXCL14 displays antimicrobial activity against respiratory tract bacteria and contributes to clearance of Streptococcus pneumoniae pulmonary infection.

    PubMed

    Dai, Chen; Basilico, Paola; Cremona, Tiziana Patrizia; Collins, Paul; Moser, Bernhard; Benarafa, Charaf; Wolf, Marlene

    2015-06-15

    CXCL14 is a chemokine with an atypical, yet highly conserved, primary structure characterized by a short N terminus and high sequence identity between human and mouse. Although it induces chemotaxis of monocytic cells at high concentrations, its physiological role in leukocyte trafficking remains elusive. In contrast, several studies have demonstrated that CXCL14 is a broad-spectrum antimicrobial peptide that is expressed abundantly and constitutively in epithelial tissues. In this study, we further explored the antimicrobial properties of CXCL14 against respiratory pathogens in vitro and in vivo. We found that CXCL14 potently killed Pseudomonas aeruginosa, Streptococcus mitis, and Streptococcus pneumoniae in a dose-dependent manner in part through membrane depolarization and rupture. By performing structure-activity studies, we found that the activity against Gram-negative bacteria was largely associated with the N-terminal peptide CXCL141-13. Interestingly, the central part of the molecule representing the β-sheet also maintained ∼62% killing activity and was sufficient to induce chemotaxis of THP-1 cells. The C-terminal α-helix of CXCL14 had neither antimicrobial nor chemotactic effect. To investigate a physiological function for CXCL14 in innate immunity in vivo, we infected CXCL14-deficient mice with lung pathogens and we found that CXCL14 contributed to enhanced clearance of Streptococcus pneumoniae, but not Pseudomonas aeruginosa. Our comprehensive studies reflect the complex bactericidal mechanisms of CXCL14, and we propose that different structural features are relevant for the killing of Gram-negative and Gram-positive bacteria. Taken together, our studies show that evolutionary-conserved features of CXCL14 are important for constitutive antimicrobial defenses against pneumonia.

  8. Periodic Bursts of Jovian Non-Io Decametric Radio Emission

    NASA Technical Reports Server (NTRS)

    Panchenko, M.; Rucker, H O.; Farrell, W. M.

    2013-01-01

    During the years 2000-2011 the radio instruments onboard Cassini, Wind and STEREO spacecraft have Recorded a large amount of the Jovian decametric radio emission (DAM). In this paper we report on the analysis of the new type of Jovian periodic radio bursts recently revealed in the decametric frequency range. These bursts, which are non-Io component of DAM, are characterized by a strong periodic reoccurrence over several Jovian days with a period approx. = 1:5% longer than the rotation rate of the planet's magnetosphere (System III). The bursts are typically observed between 4 and 12 MHz and their occurrence probability has been found to be significantly higher in the sector of Jovian Central Meridian Longitude between 300 deg. and 60 deg. (via 360 deg.). The stereoscopic multispacecraft observations have shown that the radio sources of the periodic bursts radiate in a non-axisymmetric hollow cone-like pattern and sub-corotate with Jupiter remaining active during several planet's rotations. The occurrence of the periodic non-Io DAM bursts is strongly correlated with pulses of the solar wind ram pressure at Jupiter. Moreover the periodic bursts exhibit a tendency to occur in groups every approx. 25 days. The polarization measurements have shown that the periodic bursts are right hand polarized radio emission associated with the Northern magnetic hemisphere of Jupiter. We suggest that periodic non-Io DAM bursts may be connected with the interchange instability in Io plasma torus triggered by the solar wind.

  9. Periodic bursts of Jovian non-Io decametric radio emission.

    PubMed

    Panchenko, M; Rucker, H O; Farrell, W M

    2013-03-01

    During the years 2000-2011 the radio instruments onboard Cassini, Wind and STEREO spacecraft have recorded a large amount of the Jovian decametric radio emission (DAM). In this paper we report on the analysis of the new type of Jovian periodic radio bursts recently revealed in the decametric frequency range. These bursts, which are non-Io component of DAM, are characterized by a strong periodic reoccurrence over several Jovian days with a period [Formula: see text] longer than the rotation rate of the planet's magnetosphere (System III). The bursts are typically observed between 4 and 12 MHz and their occurrence probability has been found to be significantly higher in the sector of Jovian Central Meridian Longitude between 300° and 60° (via 360°). The stereoscopic multispacecraft observations have shown that the radio sources of the periodic bursts radiate in a non-axisymmetric hollow cone-like pattern and sub-corotate with Jupiter remaining active during several planet's rotations. The occurrence of the periodic non-Io DAM bursts is strongly correlated with pulses of the solar wind ram pressure at Jupiter. Moreover the periodic bursts exhibit a tendency to occur in groups every [Formula: see text] days. The polarization measurements have shown that the periodic bursts are right hand polarized radio emission associated with the Northern magnetic hemisphere of Jupiter. We suggest that periodic non-Io DAM bursts may be connected with the interchange instability in Io plasma torus triggered by the solar wind.

  10. Periodic bursts of Jovian non-Io decametric radio emission

    PubMed Central

    Panchenko, M.; Rucker, H.O.; Farrell, W.M.

    2013-01-01

    During the years 2000–2011 the radio instruments onboard Cassini, Wind and STEREO spacecraft have recorded a large amount of the Jovian decametric radio emission (DAM). In this paper we report on the analysis of the new type of Jovian periodic radio bursts recently revealed in the decametric frequency range. These bursts, which are non-Io component of DAM, are characterized by a strong periodic reoccurrence over several Jovian days with a period ≈1.5% longer than the rotation rate of the planet's magnetosphere (System III). The bursts are typically observed between 4 and 12 MHz and their occurrence probability has been found to be significantly higher in the sector of Jovian Central Meridian Longitude between 300° and 60° (via 360°). The stereoscopic multispacecraft observations have shown that the radio sources of the periodic bursts radiate in a non-axisymmetric hollow cone-like pattern and sub-corotate with Jupiter remaining active during several planet's rotations. The occurrence of the periodic non-Io DAM bursts is strongly correlated with pulses of the solar wind ram pressure at Jupiter. Moreover the periodic bursts exhibit a tendency to occur in groups every ∼25 days. The polarization measurements have shown that the periodic bursts are right hand polarized radio emission associated with the Northern magnetic hemisphere of Jupiter. We suggest that periodic non-Io DAM bursts may be connected with the interchange instability in Io plasma torus triggered by the solar wind. PMID:23585696

  11. Periodic bursts of Jovian non-Io decametric radio emission

    NASA Astrophysics Data System (ADS)

    Panchenko, M.; Rucker, H. O.; Farrell, W. M.

    2013-03-01

    During the years 2000-2011 the radio instruments onboard Cassini, Wind and STEREO spacecraft have recorded a large amount of the Jovian decametric radio emission (DAM). In this paper we report on the analysis of the new type of Jovian periodic radio bursts recently revealed in the decametric frequency range. These bursts, which are non-Io component of DAM, are characterized by a strong periodic reoccurrence over several Jovian days with a period ≈1.5% longer than the rotation rate of the planet's magnetosphere (System III). The bursts are typically observed between 4 and 12 MHz and their occurrence probability has been found to be significantly higher in the sector of Jovian Central Meridian Longitude between 300° and 60° (via 360°). The stereoscopic multispacecraft observations have shown that the radio sources of the periodic bursts radiate in a non-axisymmetric hollow cone-like pattern and sub-corotate with Jupiter remaining active during several planet's rotations. The occurrence of the periodic non-Io DAM bursts is strongly correlated with pulses of the solar wind ram pressure at Jupiter. Moreover the periodic bursts exhibit a tendency to occur in groups every ∼25 days. The polarization measurements have shown that the periodic bursts are right hand polarized radio emission associated with the Northern magnetic hemisphere of Jupiter. We suggest that periodic non-Io DAM bursts may be connected with the interchange instability in Io plasma torus triggered by the solar wind.

  12. The Relationship between Mitochondrial Respiratory Chain Activities in Muscle and Metabolites in Plasma and Urine: A Retrospective Study

    PubMed Central

    Alban, Corinne; Fatale, Elena; Joulani, Abed; Ilin, Polina; Saada, Ann

    2017-01-01

    The relationship between 114 cases with decreased enzymatic activities of mitochondrial respiratory chain (MRC) complexes I-V (C I-V) in muscle and metabolites in urine and plasma was retrospectively examined. Less than 35% disclosed abnormal plasma amino acids and acylcarnitines, with elevated alanine and low free carnitine or elevated C4-OH-carnitine as the most common findings, respectively. Abnormal urine organic acids (OA) were detected in 82% of all cases. In CI and CII defects, lactic acid (LA) in combination with other metabolites was the most common finding. 3-Methylglutaconic (3MGA) acid was more frequent in CIV and CV, while Tyrosine metabolites, mainly 4-hydroxyphenyllactate, were common in CI and IV defects. Ketones were present in all groups but more prominent in combined deficiencies. There was a significant strong correlation between elevated urinary LA and plasma lactate but none between urine Tyrosine metabolites and plasma Tyrosine or urinary LA and plasma Alanine. All except one of 14 cases showed elevated FGF21, but correlation with urine OA was weak. Although this study is limited, we conclude that urine organic acid test in combination with plasma FGF21 determination are valuable tools in the diagnosis of mitochondrial diseases. PMID:28287425

  13. Gamma Ray Bursts

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  14. UWB dual burst transmit driver

    SciTech Connect

    Dallum, Gregory E; Pratt, Garth C; Haugen, Peter C; Zumstein, James M; Vigars, Mark L; Romero, Carlos E

    2012-04-17

    A dual burst transmitter for ultra-wideband (UWB) communication systems generates a pair of precisely spaced RF bursts from a single trigger event. An input trigger pulse produces two oscillator trigger pulses, an initial pulse and a delayed pulse, in a dual trigger generator. The two oscillator trigger pulses drive a gated RF burst (power output) oscillator. A bias driver circuit gates the RF output oscillator on and off and sets the RF burst packet width. The bias driver also level shifts the drive signal to the level that is required for the RF output device.

  15. Spatiotemporal chaos from bursting dynamics

    SciTech Connect

    Berenstein, Igal; De Decker, Yannick

    2015-08-14

    In this paper, we study the emergence of spatiotemporal chaos from mixed-mode oscillations, by using an extended Oregonator model. We show that bursting dynamics consisting of fast/slow mixed mode oscillations along a single attractor can lead to spatiotemporal chaotic dynamics, although the spatially homogeneous solution is itself non-chaotic. This behavior is observed far from the Hopf bifurcation and takes the form of a spatiotemporal intermittency where the system locally alternates between the fast and the slow phases of the mixed mode oscillations. We expect this form of spatiotemporal chaos to be generic for models in which one or several slow variables are coupled to activator-inhibitor type of oscillators.

  16. Respiratory patterns and metabolism in tenebrionid and carabid beetles from the Simpson Desert, Australia.

    PubMed

    Duncan, F D; Dickman, C R

    2001-12-01

    The respiratory physiology of four species of Australian desert-dwelling beetle was examined using a flow-through respirometry system over the temperature range of 20-40°C. The two species of tenebrionid beetles (Heleus waitei and Pterohelaeus sp.) did not exhibit the discontinuous gas exchange cycles (DGC), a mechanism to possibly reduce respiratory water loss rates, observed in other arid-dwelling beetles. There were small increases in metabolic rate with temperature resulting in a Q 10 of 1.84 for H. waitei and 1.99 for Pterohelaeus sp. Furthermore, H. waitei has no increase in metabolic rate over the temperature range 25-35°C (Q 10=1). The two species of carabid beetles (Cerotalis sp. and Carenum sp.) displayed the DGC respiratory pattern, having long flutter and burst periods. Both species also exhibited spiracular movement or muscular pumping in the burst period. Relatively low Q 10 values of 1.31 and 1.64 were measured for Cerotalis sp. and Carenum sp., respectively. Cerotalis sp. had no increase in metabolic rate over the temperature range 20-35°C (Q 10=1). In both species the temperature-associated increases in metabolic rate were modulated by increases in DGC frequency. All the four beetle species studied have fused elytra, a closed subelytral cavity and are nocturnally active, which should assist in reducing respiratory water loss rates, and occupy similar microhabitats. Thus we propose that the difference in respiratory patterns found between the tenebrionid and carabid beetles is related to their thorax morphology, food type and food availability.

  17. Changes in the Size of the Active Microbial Pool Explain Short-Term Soil Respiratory Responses to Temperature and Moisture

    PubMed Central

    Salazar-Villegas, Alejandro; Blagodatskaya, Evgenia; Dukes, Jeffrey S.

    2016-01-01

    abiotic conditions activated soil microorganisms. We conclude that soil respiratory responses to short-term changes in environmental conditions are better explained by changes in AMB than in TMB. These results suggest that decomposition models that explicitly represent microbial carbon pools should take into account the active microbial pool, and researchers should be cautious in comparing modeled microbial pool sizes with measurements of TMB. PMID:27148213

  18. Low-Frequency Type III Bursts and Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Nat; Makela, Pertti

    2010-01-01

    We analyzed the coronal mass ejections (CMEs), flares, and type 11 radio bursts associated with a set of six low frequency (<14 MHz) extended type III bursts from active region 10588. The durations were measured at 1 and 14 MHz using high resolution data from Wind/WAVES and were within the range (>15 min) normally used to define these bursts. All but one of the type III bursts was not associated with a type 11 burst in the metric or longer wavelength domains. The burst without type 11 burst also lacked a solar energetic particle (SEP) event at energies >25 MeV. The 1-MHz duration of the type III burst (28 min) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. The CMEs were of similar speeds and the flares are also of similar size and duration. This study suggests that the type III burst duration may not be a good indicator of an SEP event.

  19. Purification of Ovine Respiratory Complex I Results in a Highly Active and Stable Preparation.

    PubMed

    Letts, James A; Degliesposti, Gianluca; Fiedorczuk, Karol; Skehel, Mark; Sazanov, Leonid A

    2016-11-18

    NADH-ubiquinone oxidoreductase (complex I) is the largest (∼1 MDa) and the least characterized complex of the mitochondrial electron transport chain. Because of the ease of sample availability, previous work has focused almost exclusively on bovine complex I. However, only medium resolution structural analyses of this complex have been reported. Working with other mammalian complex I homologues is a potential approach for overcoming these limitations. Due to the inherent difficulty of expressing large membrane protein complexes, screening of complex I homologues is limited to large mammals reared for human consumption. The high sequence identity among these available sources may preclude the benefits of screening. Here, we report the characterization of complex I purified from Ovis aries (ovine) heart mitochondria. All 44 unique subunits of the intact complex were identified by mass spectrometry. We identified differences in the subunit composition of subcomplexes of ovine complex I as compared with bovine, suggesting differential stability of inter-subunit interactions within the complex. Furthermore, the 42-kDa subunit, which is easily lost from the bovine enzyme, remains tightly bound to ovine complex I. Additionally, we developed a novel purification protocol for highly active and stable mitochondrial complex I using the branched-chain detergent lauryl maltose neopentyl glycol. Our data demonstrate that, although closely related, significant differences exist between the biochemical properties of complex I prepared from ovine and bovine mitochondria and that ovine complex I represents a suitable alternative target for further structural studies.

  20. Fermi/GAMMA-RAY BURST MONITOR OBSERVATIONS OF SGR J0501+4516 BURSTS

    SciTech Connect

    Lin Lin; Zhang Shuangnan; Kouveliotou, Chryssa; Van der Horst, Alexander J.; Finger, Mark H.; Guiriec, Sylvain; Preece, Robert; Chaplin, Vandiver; Bhat, Narayan; Woods, Peter M.; Goegues, Ersin; Kaneko, Yuki; Scargle, Jeffrey; Von Kienlin, Andreas; Watts, Anna L.; Wijers, Ralph A. M. J.; Gehrels, Neil; Harding, Alice

    2011-10-01

    We present our temporal and spectral analyses of 29 bursts from SGR J0501+4516, detected with the gamma-ray burst monitor on board the Fermi Gamma-ray Space Telescope during 13 days of the source's activation in 2008 (August 22- September 3). We find that the T{sub 90} durations of the bursts can be fit with a log-normal distribution with a mean value of {approx}123 ms. We also estimate for the first time event durations of soft gamma repeater (SGR) bursts in photon space (i.e., using their deconvolved spectra) and find that these are very similar to the T{sub 90} values estimated in count space (following a log-normal distribution with a mean value of {approx}124 ms). We fit the time-integrated spectra for each burst and the time-resolved spectra of the five brightest bursts with several models. We find that a single power law with an exponential cutoff model fits all 29 bursts well, while 18 of the events can also be fit with two blackbody functions. We expand on the physical interpretation of these two models and we compare their parameters and discuss their evolution. We show that the time-integrated and time-resolved spectra reveal that E{sub peak} decreases with energy flux (and fluence) to a minimum of {approx}30 keV at F = 8.7 x 10{sup -6} erg cm{sup -2} s{sup -1}, increasing steadily afterward. Two more sources exhibit a similar trend: SGRs J1550-5418 and 1806-20. The isotropic luminosity, L{sub iso}, corresponding to these flux values is roughly similar for all sources (0.4-1.5 x 10{sup 40} erg s{sup -1}).

  1. Brief (<1 sec) delays to particle activation, and their influence on deposition patterns in the respiratory system

    NASA Astrophysics Data System (ADS)

    Ruehl, C. R.; Kleeman, M. J.; Chuang, P. Y.; Nenes, A.

    2010-12-01

    Recent field measurements have demonstrated that some ambient particles can act as cloud condensation nuclei (CCN) when exposed to water vapor supersaturations only after delays on the order of several seconds. It is therefore plausible that other CCN experience even shorter delays (i.e. one second or less) before activation. Such brief delays could prevent activation in two situations: in cases when maximum supersaturation in an updraft is brief, which might be expected in a polluted cloud, and in the human respiratory system, in which supersaturation can occur during inhalation. The latter situation is relevant because such a delay could allow particles to penetrate more deeply into the lungs and thus may enhance any health effects associated with the particles. We modified a lung deposition model to account for particle hygroscopicity to determine the size and composition ranges of particles that might have their deposition patterns affected by such delays. We also made measurements of the CCN activity of particles sampled in Davis, CA, during July 2010 at a site approximately one km from interstate 80. We used a continuous-flow thermal gradient chamber that had been modified to produce high supersaturations for approximately one second or less, and compared the concentration of CCN produced during a “slow” (~1 s) exposure and a “fast” (<0.5 sec) exposure. [CCN]fast was equal to 850 +/- 850 cm-3, while [CCN]slow was 1610 +/- 1190 cm-3, suggesting that approximately half of ambient CCN experience brief delays to activation. The [CCN]fast:[CCN]slow ratio ranged from approximately 0.2 to 1, with lower values typically in the morning and higher values in the late afternoon/evening. The [CCN]fast:[CCN]slow ratio for ammonium sulfate calibration aerosol was 1.10 +/- 0.30. Analysis of the diameter distributions of the resulting droplets supports the hypothesis that variation in this ratio is due to brief kinetic delays. We use these inferred delays in our lung

  2. In vitro effect of copper chloride exposure on reactive oxygen species generation and respiratory chain complex activities of mitochondria isolated from broiler liver.

    PubMed

    Su, Rongsheng; Wang, Rongmei; Guo, Shining; Cao, Huabin; Pan, Jiaqiang; Li, Chengmei; Shi, Dayou; Tang, Zhaoxin

    2011-12-01

    This study is to examine if Cu(2+) can act directly on mitochondria or indirectly by producing reactive oxygen species (ROS), isolated broiler hepatic mitochondria were exposed to different concentrations of Cu(2+) (10, 30, 50 μM). Respiratory chain complex activities, ROS generation, respiratory control ratio (RCR) and mitochondrial membrane potential were investigated. Dose-dependent inhibition of respiratory chain complexes and induction of ROS were observed, which coincided with decreasing RCR both with glutamate + malate or succinate. Further investigation indicated that the membrane potential determined by rhodamine 123 release decreased after CuCl(2) exposure at 30 and 50 μM. In addition, the effects of the antioxidants NAC (200 μM) and GSH (200 μM) were studied at 50 μM Cu(2+). The results indicate that Cu can induce mitochondrial dysfunction in excessive dose and the effect of Cu(2+) exposure on respiratory chain is not site-specific, and antioxidants can protect the mitochondrial function by reducing the formation of free radicals.

  3. Applicability of tetrazolium salts for the measurement of respiratory activity and viability of groundwater bacteria

    USGS Publications Warehouse

    Hatzinger, P.B.; Palmer, P.; Smith, R.L.; Penarrieta, C.T.; Yoshinari, T.

    2003-01-01

    A study was undertaken to measure aerobic respiration by indigenous bacteria in a sand and gravel aquifer on western Cape Cod, MA using tetrazolium salts and by direct oxygen consumption using gas chromatography (GC). In groundwater and aquifer slurries, the rate of aerobic respiration calculated from the direct GC assay was more than 600 times greater than that using the tetrazolium salt 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT). To explain this discrepancy, the toxicity of INT and two additional tetrazolium salts, sodium 3???-[1-(phenylamino)-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6-nitro) benzenesulfonic acid hydrate (XTT) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), to bacterial isolates from the aquifer was investigated. Each of the three tetrazolium salts was observed to be toxic to some of the groundwater isolates at concentrations normally used in electron transport system (ETS) and viability assays. For example, incubation of cells with XTT (3 mM) caused the density of four of the five groundwater strains tested to decline by more than four orders of magnitude. A reasonable percentage (>57%) of cells killed by CTC and INT contained visible formazan crystals (the insoluble, reduced form of the salts) after 4 h of incubation. Thus, many of the cells reduced enough CTC or INT prior to dying to be considered viable by microscopic evaluation. However, one bacterium (Pseudomonas fluorescens) that remained viable and culturable in the presence of INT and CTC, did not incorporate formazan crystals into more than a few percent of cells, even after 24 h of incubation. This strain would be considered nonviable based on traditional tetrazolium salt reduction assays. The data show that tetrazolium salt assays are likely to dramatically underestimate total ETS activity in groundwater and, although they may provide a reasonable overall estimate of viable cell numbers in a community of groundwater bacteria, some specific strains may

  4. Respiratory gas transport, metabolic status, and locomotor capacity of the Christmas Island red crab Gecarcoidea natalis assessed in the field with respect to dichotomous seasonal activity levels.

    PubMed

    Adamczewska, A M; Morris, S

    2000-05-01

    Red crabs, Gecarcoidea natalis, exhibit seasonal activity patterns: low activity during the dry season when they shelter in burrows to avoid dehydration, and high activity during the wet season. Red crabs were examined in situ in the rainforest of Christmas Island to determine if there were underlying seasonal differences in the capacity for exercise and associated metabolism. During both seasons, free-ranging (FR) crabs engaged in their normal activities and, together with crabs induced to exercise for 5 min, were sampled for haemolymph and muscle tissue. Respiratory gases in the haemolymph and key metabolites were measured to assess differences in metabolic status of FR and exercised crabs. Actively foraging FR crabs during the wet season exhibited a relative haemolymph hypoxia (2.9 kPa) and accumulated an extra 3 mmol. litre(-1) of CO(2) compared to the relatively inactive FR crabs during the dry season. Wet-season crabs appeared to be in a state of relative respiratory acidosis compared to dry-season animals. This hypercapnia may arise as a consequence of a relative hypoventilation in animals with a relatively higher metabolic rate during the wet season. Oxygenation of pulmonary and arterial haemolymph was similar and remained high after 5 min of exercise, indicating that the gills and lungs functioned similarly in gas exchange in both FR and exercised crabs. During exercise, venous O(2) reserves decreased and red crabs experienced a mixed respiratory/metabolic acidosis. Similar changes, after 5 min of enforced exercise, in metabolite concentrations, pH and respiratory gas status in the haemolymph during both sampling seasons suggest that the crabs maintain similar capacity to increase exercise during the wet and the dry seasons, despite the differences in underlying physiological status. This is important since after prolonged inactivity during the dry season, with the arrival of moonsoonal rains, red crabs must engage in their annual breeding migration.

  5. L-carnosine modulates respiratory burst and reactive oxygen species production in neutrophil biochemistry and function: may oral dosage form of non-hydrolized dipeptide L-carnosine complement anti-infective anti-influenza flu treatment, prevention and self-care as an alternative to the conventional vaccination?

    PubMed

    Babizhayev, Mark A; Deyev, Anatoliy I; Yegorov, Yegor E

    2014-05-01

    Influenza A is a viral disease of global dimension, presenting with high morbidity and mortality in annual epidemics, and in pandemics which are of infrequent occurrence but which have very high attack rates. Influenza vaccines of the future must be directed toward use of conserved group-specific viral antigens, such as are present in transitional proteins which are exposed during the fusion of virus to the host cell. Influenza probes revealed a continuing battle for survival between host and parasite in which the host population updates the specificity of its pool of humoral immunity by contact with and response to infection with the most recent viruses which possess altered antigenic specificity in their hemagglutinin (HA) ligand. It is well known that the HA protein is found on the surface of the influenza virus particle and is responsible for binding to receptors on host cells and initiating infection. Polymorphonuclear neutrophils (PMN) have been reported to be involved in the initial host response to influenza A virus (IAV). Early after IAV infection, neutrophils infiltrate the airway probably due to release of chemokines that attract PMN. Clearly, severe IAV infection is characterized by increased neutrophil influx into the lung or upper respiratory tract. Carnosine (β-alanyl-L-histidine) and anserine (N-β-alanyl-1-methyl-L-histidine) are found in skeletal muscle of most vertebrates, including those used for food; for example, 100 g of chicken breast contains 400 mg (17.6 mmol/L) of carnosine and 1020 mg (33.6 mmol/l) of anserine. Carnosine-stimulated respiratory burst in neutrophils is a universal biological mechanism of influenza virus destruction. Our own studies revealed previously unappreciated functional effects of carnosine and related histidine containing compounds as a natural biological prevention and barrier against Influenza virus infection, expand public understanding of the antiviral properties of imidazole-containing dipeptide based

  6. Mycorrhiza-induced lower oxidative burst is related with higher antioxidant enzyme activities, net H2O2 effluxes, and Ca2+ influxes in trifoliate orange roots under drought stress.

    PubMed

    Zou, Ying-Ning; Huang, Yong-Ming; Wu, Qiang-Sheng; He, Xin-Hua

    2015-02-01

    Mechanisms of arbuscular mycorrhiza (AM)-induced lower oxidative burst of host plants under drought stress (DS) are not elucidated. A noninvasive microtest technology (NMT) was used to investigate the effects of Funneliformis mosseae on net fluxes of root hydrogen peroxide (H2O2) and calcium ions (Ca2+) in 5-month-old Poncirus trifoliata, in combination with catalase (CAT) and superoxide dismutase (SOD) activities as well as tissue superoxide radical (O2•-) and H2O2 concentrations under DS and well-watered (WW) conditions. A 2-month DS (55% maximum water holding capacity of growth substrates) significantly inhibited AM fungal root colonization, while AM symbiosis significantly increased plant biomass production, irrespective of water status. F. mosseae inoculation generally increased SOD and CAT activity but decreased O2•- and H2O2 concentrations in leaves and roots under WW and DS. Compared with non-AM seedlings, roots of AM seedlings had significantly higher net H2O2 effluxes and net Ca2+ influxes, especially in the meristem zone, but lower net H2O2 efflux in the elongation zone. Net Ca2+ influxes into roots were significantly positively correlated with root net H2O2 effluxes but negatively with root H2O2 concentrations. Results from this study suggest that AM-induced lower oxidative burst is related with higher antioxidant enzyme activities, root net H2O2 effluxes, and Ca2+ influxes under WW and DS.

  7. Respiratory Home Health Care

    MedlinePlus

    ... Healthy Living > Living With Lung Disease > Respiratory Home Health Care Font: Aerosol Delivery Oxygen Resources Immunizations Pollution Nutrition ... Disease Articles written by Respiratory Experts Respiratory Home Health Care Respiratory care at home can contribute to improved ...

  8. Mitochondrial Respiratory Defect Causes Dysfunctional Lactate Turnover via AMP-activated Protein Kinase Activation in Human-induced Pluripotent Stem Cell-derived Hepatocytes*

    PubMed Central

    Im, Ilkyun; Jang, Mi-jin; Park, Seung Ju; Lee, Sang-Hee; Choi, Jin-Ho; Yoo, Han-Wook; Kim, Seyun; Han, Yong-Mahn

    2015-01-01

    A defective mitochondrial respiratory chain complex (DMRC) causes various metabolic disorders in humans. However, the pathophysiology of DMRC in the liver remains unclear. To understand DMRC pathophysiology in vitro, DMRC-induced pluripotent stem cells were generated from dermal fibroblasts of a DMRC patient who had a homoplasmic mutation (m.3398T→C) in the mitochondrion-encoded NADH dehydrogenase 1 (MTND1) gene and that differentiated into hepatocytes (DMRC hepatocytes) in vitro. DMRC hepatocytes showed abnormalities in mitochondrial characteristics, the NAD+/NADH ratio, the glycogen storage level, the lactate turnover rate, and AMPK activity. Intriguingly, low glycogen storage and transcription of lactate turnover-related genes in DMRC hepatocytes were recovered by inhibition of AMPK activity. Thus, AMPK activation led to metabolic changes in terms of glycogen storage and lactate turnover in DMRC hepatocytes. These data demonstrate for the first time that energy depletion may lead to lactic acidosis in the DMRC patient by reduction of lactate uptake via AMPK in liver. PMID:26491018

  9. Swift's 500th Gamma Ray Burst

    NASA Video Gallery

    On April 13, 2010, NASA's Swift Gamma-ray Burst Explorer satellite discovered its 500th burst. Swift's main job is to quickly localize each gamma-ray burst (GRB), report its position so that others...

  10. Powerful Radio Burst Indicates New Astronomical Phenomenon

    NASA Astrophysics Data System (ADS)

    2007-09-01

    Hawking. The newly-discovered radio burst, the researchers said, might be the "last gasp" of a black hole as it finally evaporates completely. "We're actively looking for more of these powerful, short bursts, in other archival pulsar surveys, and hope to resolve the mystery of their origin," said McLaughlin. "In addition, if we can associate these events with galaxies of known distance, the radio dispersion we measure can be used as a powerful new way to determine the amount of material in intergalactic space," she added. The Parkes radio telescope is part of the Australia Telescope, which is funded by the Commonwealth of Australia for operation as a National Facility. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  11. Administration of Harmine and Imipramine Alters Creatine Kinase and Mitochondrial Respiratory Chain Activities in the Rat Brain

    PubMed Central

    Réus, Gislaine Z.; Stringari, Roberto B.; Gonçalves, Cinara L.; Scaini, Giselli; Carvalho-Silva, Milena; Jeremias, Gabriela C.; Jeremias, Isabela C.; Ferreira, Gabriela K.; Streck, Emílio L.; Hallak, Jaime E.; Zuardi, Antônio W.; Crippa, José A.; Quevedo, João

    2012-01-01

    The present study evaluated mitochondrial respiratory chain and creatine kinase activities after administration of harmine (5, 10, and 15 mg/kg) and imipramine (10, 20, and 30 mg/kg) in rat brain. After acute treatment occurred an increase of creatine kinase in the prefrontal with imipramine (20 and 30 mg/kg) and harmine in all doses, in the striatum with imipramine (20 and 30 mg/kg) and harmine (5 and 10 mg/kg); harmine (15 mg/kg) decreased creatine kinase. In the chronic treatment occurred an increase of creatine kinase with imipramine (20 mg/kg), harmine (5 mg/kg) in the prefrontal with imipramine (20 and 30 mg/kg) and harmine (5 and 10 mg/kg) in the striatum. In the acute treatment, the complex I increased in the prefrontal with harmine (15 mg/kg) and in the striatum with harmine (10 mg/kg); the complex II decreased with imipramine (20 and 30 mg/kg) in the striatum; the complex IV increased with imipramine (30 mg/kg) in the striatum. In the chronic treatment, the complex I increased with harmine (5 mg/kg) in the prefrontal; the complex II increased with imipramine (20 mg/kg) in the prefrontal; the complex IV increased with harmine (5 mg/kg) in the striatum. Finally, these findings further support the hypothesis that harmine and imipramine could be involved in mitochondrial function. PMID:21969912

  12. The effect of feedback respiratory exercise on muscle activity, craniovertebral angle, and neck disability index of the neck flexors of patients with forward head posture

    PubMed Central

    Kang, Jeong-il; Jeong, Dae-Keun; Choi, Hyun

    2016-01-01

    [Purpose] This study aimed to simultaneously investigate the activities of the sternocleidomastoid muscle and scalenus anterior muscle, which are agonists of neck and breathing accessory muscles, by implementing breathing exercises. [Subjects and Methods] Thirteen subjects were selected for the experimental group, which performed feedback respiratory exercises with McKenzie exercises, and 12 subjects were selected for the control group, which performed McKenzie exercises alone. The intervention program was performed for 30 minutes a session, once a day, four times a week, and for 2 weeks before conducting the experiment. Before intervention, muscle activity was measured using surface electromyogram, and the neck disability index was evaluated. [Results] There were meaningful differences in activities of the sternocleidomastoid muscle and the scalenus anterior muscle, craniovertebral angle, and neck disability index within both the experimental group and control group after intervention. There also were meaningful differences in sternocleidomastoid muscle and neck disability index changes between groups. [Conclusion] Neck flexors as accessory respiratory muscle can affect inefficient respiratory imbalance of forward head posture patients. Multimodal intervention method should be studied continually and not be exposed to upper chest breathing patterns by preventing such phenomenon. PMID:27799674

  13. The effect of feedback respiratory exercise on muscle activity, craniovertebral angle, and neck disability index of the neck flexors of patients with forward head posture.

    PubMed

    Kang, Jeong-Il; Jeong, Dae-Keun; Choi, Hyun

    2016-09-01

    [Purpose] This study aimed to simultaneously investigate the activities of the sternocleidomastoid muscle and scalenus anterior muscle, which are agonists of neck and breathing accessory muscles, by implementing breathing exercises. [Subjects and Methods] Thirteen subjects were selected for the experimental group, which performed feedback respiratory exercises with McKenzie exercises, and 12 subjects were selected for the control group, which performed McKenzie exercises alone. The intervention program was performed for 30 minutes a session, once a day, four times a week, and for 2 weeks before conducting the experiment. Before intervention, muscle activity was measured using surface electromyogram, and the neck disability index was evaluated. [Results] There were meaningful differences in activities of the sternocleidomastoid muscle and the scalenus anterior muscle, craniovertebral angle, and neck disability index within both the experimental group and control group after intervention. There also were meaningful differences in sternocleidomastoid muscle and neck disability index changes between groups. [Conclusion] Neck flexors as accessory respiratory muscle can affect inefficient respiratory imbalance of forward head posture patients. Multimodal intervention method should be studied continually and not be exposed to upper chest breathing patterns by preventing such phenomenon.

  14. An interacting loop model of solar flare bursts

    NASA Technical Reports Server (NTRS)

    Emslie, A. G.

    1981-01-01

    As a result of the strong heating produced at chromospheric levels during a solar flare burst, the local gas pressure can transiently attain very large values in certain regions. The effectiveness of the surrounding magnetic field at confining this high pressure plasma is therefore reduced and the flaring loop becomes free to expand laterally. In so doing it may drive magnetic field lines into neighboring, nonflaring, loops in the same active region, causing magnetic reconnection to take place and triggering another flare burst. The features of this interacting loop model are found to be in good agreement with the energetics and time structure of flare associated solar hard X-ray bursts.

  15. Exploratory study of EEG burst characteristics in preterm infants.

    PubMed

    Simayijiang, Zhayida; Backman, Sofia; Ulén, Johannes; Wikström, Sverre; Åstrom, Kalle

    2013-01-01

    In this paper, we study machine learning techniques and features of electroencephalography activity bursts for predicting outcome in extremely preterm infants. It was previously shown that the distribution of interburst interval durations predicts clinical outcome, but in previous work the information within the bursts has been neglected. In this paper, we perform exploratory analysis of feature extraction of burst characteristics and use machine learning techniques to show that such features could be used for outcome prediction. The results are promising, but further verification in larger datasets is needed to obtain conclusive results.

  16. Bursts de raios gama

    NASA Astrophysics Data System (ADS)

    Braga, J.

    2003-02-01

    Nos últimos anos, graças principalmente aos dados obtidos pelo Compton Gamma-Ray Observatory e pelo satélite ítalo-holandês BeppoSAX, grandes avanços foram obtidos no nosso conhecimento sobre os fascinantes e enigmáticos fenômenos conhecidos por "bursts"de raios gama. Neste trabalho é feita uma revisão sobre a fenomenologia desses misteriosos objetos e são apresentados os desenvolvimentos recentes nessa área palpitante da astrofísica moderna, ressaltando tanto os resultados observacionais obtidos até o momento quanto os modelos teóricos propostos para explixá-los.

  17. Quantum key based burst confidentiality in optical burst switched networks.

    PubMed

    Balamurugan, A M; Sivasubramanian, A

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

  18. Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

    PubMed Central

    Balamurugan, A. M.; Sivasubramanian, A.

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks. PMID:24578663

  19. Respiratory Distress

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The University of Miami School of Medicine asked the Research Triangle Institute for assistance in improvising the negative pressure technique to relieve respiratory distress in infants. Marshall Space Flight Center and Johnson Space Center engineers adapted this idea to the lower-body negative-pressure system seals used during the Skylab missions. Some 20,000 babies succumb to respiratory distress in the U.S. each year, a condition in which lungs progressively lose their ability to oxygenate blood. Both positive and negative pressure techniques have been used - the first to force air into lungs, the second to keep infant's lungs expanded. Negative pressure around chest helps the baby expand his lungs and maintain proper volume of air. If doctors can keep the infant alive for four days, the missing substance in the lungs will usually form in sufficient quantity to permit normal breathing. The Skylab chamber and its leakproof seals were adapted for medical use.

  20. Burst Detector Sensitivity: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2005-01-01

    I compare the burst detection sensitivity of CGRO's BATSE, Swift's BAT, the GLAST Burst Monitor (GBM) and EXIST as a function of a burst s spectrum and duration. A detector's overall burst sensitivity depends on its energy sensitivity and set of accumulations times (Delta)t; these two factors shape the detected burst population. For example, relative to BATSE, the BAT s softer energy band decreases the detection rate of short, hard bursts, while the BAT s longer accumulation times increase the detection rate of long, soft bursts. Consequently, Swift is detecting long, low fluence bursts (2-3 x fainter than BATSE).

  1. Bifurcations of the respiratory pattern produced with phasic vagal stimulation in the rat.

    PubMed

    Sammon, M; Romaniuk, J R; Bruce, E N

    1993-08-01

    Geometric methods from nonlinear dynamics are employed to evaluate dynamic processing of vagal afferent information by the respiratory central pattern generator (RCPG). While measuring airflow and diaphragm EMG, we applied brief electrical stimuli (40- to 130-ms duration) to one afferent vagus of bilaterally vagotomized urethan-anesthetized rats during every breath at various phases of the respiratory cycle. Stimuli applied during early or late inspiration of every breath evoke highly predictable one-dimensional responses: reversible (graded inhibition) or irreversible (off-switching) inhibition of inspiratory activity, respectively. Stimulation during midinspiration produces higher-dimensional oscillations that wander unpredictably over a continuum of graded inhibition and off-switching; "spiral" attractors and "horseshoe" return maps at this phase are characteristic of Silnikov's bifurcation. Stimuli applied during early expiration always prolonged expiratory duration, but those delivered during midexpiration evoked unpredictable wandering between prolongations and shortening of expiratory duration. A narrow time window surrounds the expiratory-inspiratory (E-I) transition, where stimuli elicit either breaths of short duration and low amplitude (irreversible E-I transition, decreased total respiratory cycle duration) or transient bursts of inspiratory activity at the E-I transition followed by a prolonged breath (reversible E-I transition, increased total respiratory cycle duration). We conclude that RCPG "gating" of and adaptation to vagal feedback combine to produce complex breath-to-breath dynamics in the rat that are consistent with low-dimensional chaos.

  2. Physiological noise correction using ECG-derived respiratory signals for enhanced mapping of spontaneous neuronal activity with simultaneous EEG-fMRI.

    PubMed

    Abreu, Rodolfo; Nunes, Sandro; Leal, Alberto; Figueiredo, Patrícia

    2016-08-12

    The study of spontaneous brain activity based on BOLD-fMRI may be seriously compromised by the presence of signal fluctuations of non-neuronal origin, most prominently due to cardiac and respiratory mechanisms. Methods used for modeling and correction of the so-called physiological noise usually rely on the concurrent measurement of cardiac and respiratory signals. In simultaneous EEG-fMRI recordings, which are primarily aimed at the study of spontaneous brain activity, the electrocardiogram (ECG) is typically measured as part of the EEG setup but respiratory data are not generally available. Here, we propose to use the ECG-derived respiratory (EDR) signal estimated by Empirical Mode Decomposition (EMD) as a surrogate of the respiratory signal, for retrospective physiological noise correction of typical simultaneous EEG-fMRI data. A physiological noise model based on these physiological signals (P-PNM) complemented with fMRI-derived noise regressors was generated, and evaluated, for 17 simultaneous EEG-fMRI datasets acquired from a group of seven epilepsy patients imaged at 3T. The respiratory components of P-PNM were found to explain BOLD variance significantly in addition to the cardiac components, suggesting that the EDR signal was successfully extracted from the ECG, and P-PNM outperformed an image-based model (I-PNM) in terms of total BOLD variance explained. Further, the impact of the correction using P-PNM on fMRI mapping of patient-specific epileptic networks and the resting-state default mode network (DMN) was assessed in terms of sensitivity and specificity and, when compared with an ICA-based procedure and a standard pre-processing pipeline, P-PNM achieved the best performance. Overall, our results support the feasibility and utility of extracting physiological noise models of the BOLD signal resorting to ECG data exclusively, with substantial impact on the simultaneous EEG-fMRI mapping of resting-state networks, and, most importantly, epileptic networks

  3. Burst Firing is a Neural Code in an Insect Auditory System

    PubMed Central

    Eyherabide, Hugo G.; Rokem, Ariel; Herz, Andreas V. M.; Samengo, Inés

    2008-01-01

    Various classes of neurons alternate between high-frequency discharges and silent intervals. This phenomenon is called burst firing. To analyze burst activity in an insect system, grasshopper auditory receptor neurons were recorded in vivo for several distinct stimulus types. The experimental data show that both burst probability and burst characteristics are strongly influenced by temporal modulations of the acoustic stimulus. The tendency to burst, hence, is not only determined by cell-intrinsic processes, but also by their interaction with the stimulus time course. We study this interaction quantitatively and observe that bursts containing a certain number of spikes occur shortly after stimulus deflections of specific intensity and duration. Our findings suggest a sparse neural code where information about the stimulus is represented by the number of spikes per burst, irrespective of the detailed interspike-interval structure within a burst. This compact representation cannot be interpreted as a firing-rate code. An information-theoretical analysis reveals that the number of spikes per burst reliably conveys information about the amplitude and duration of sound transients, whereas their time of occurrence is reflected by the burst onset time. The investigated neurons encode almost half of the total transmitted information in burst activity. PMID:18946533

  4. Effects of image noise, respiratory motion, and motion compensation on 3D activity quantification in count-limited PET images

    NASA Astrophysics Data System (ADS)

    Siman, W.; Mawlawi, O. R.; Mikell, J. K.; Mourtada, F.; Kappadath, S. C.</