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Sample records for gamma activation of115in

  1. gamma. -hexachlorocyclohexane (. gamma. -HCH) activates washed rabbit platelets

    SciTech Connect

    Lalau-Keraly, C.; Delautier, D.; Benveniste, J.; Puiseux-Dao, S.

    1986-03-01

    In guinea-pig macrophages, ..gamma..-HCH triggers activation of the phosphatidylinositol cycle and Ca/sup 2 +/ mobilization. Since these two biochemical events are also involved in platelet activation, the authors examined the effects of ..gamma..-HCH on washed rabbit platelets. Release of /sup 14/C-serotonin (/sup 14/C-5HT) and ATP from platelets prelabelled with /sup 14/C-5HT was measured simultaneously with aggregation. ..gamma..-HCH induced shape-change, aggregation and release reaction of platelets. Maximal aggregation (89 arbitrary units, AU), was observed using 170 ..mu..M ..gamma..-HCH, and was associated with 38.1 +/- 6.9% and 161 +/- 48 nM for /sup 14/C-5HT and ATP release respectively (mean +/- 1 SD, n=3). Using 80 ..mu..M ..gamma..-HCH yielded 18 AU, 12.8 +/- 1.0% and 27 +/- 14 nM for aggregation, C-5HT and ATP release respectively (n=3). No effect was observed with 40 ..mu.. M ..gamma..-HCH. Aspirin (ASA), a cyclooxygenase blocker, did not affect ..gamma..-HCH-induced platelet activation. Apyrase (APY), an ADP scavenger, inhibited by 90% aggregation induced by 170 ..mu..M ..gamma..-HCH and slightly inhibited (15%) the /sup 14/C-5HT release. In the presence of both ASA and APY, 96% inhibition of aggregation and 48% inhibition of /sup 14/C-5HT release were observed. Thus, ..gamma..-HCH induced platelet activation in a dose-dependent manner ADP, but not cyclooxygenase-dependent arachidonate metabolites, is involved in ..gamma..-HCH-induced aggregation, whereas, both appear to play a role in ..gamma..-HCH-induced release reaction.

  2. Gamma source for active interrogation

    DOEpatents

    Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

    2009-09-29

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

  3. Gamma source for active interrogation

    SciTech Connect

    Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

    2012-10-02

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

  4. Sex differences, gamma activity and schizophrenia.

    PubMed

    Slewa-Younan, S; Gordon, E; Williams, L; Haig, A R; Goldberg, E

    2001-03-01

    This study explores the possibility that the more favourable clinical prognosis in females with schizophrenia may be associated with their greater network interconnectedness, which is possibly reflected in enhanced "Gamma" (40 Hz) electrical brain activity. An auditory "oddball" task was administered to 35 patients with schizophrenia and 35 age and sex matched controls (25 males and 10 females). Peak Gamma amplitude (from a time series of Gamma activity averaged for 40 target stimuli, as well as the immediately preceding 40 background tones) was examined across 19 sites. Peak Gamma activity occurred 250 to 450 ms in targets and 350 to 550 ms in backgrounds. Multiple within and between group MANOVAs were undertaken analysing both Peak Gamma amplitude (microvolts) and latency (milliseconds). Within-group, the control males showed a pattern of earlier Gamma latency in the right compared with the left hemisphere (F(1, 33)=3.70, p<.06), while control females exhibited delayed latency frontally compared with the posterior region (F(1, 33)=6.25, p<.04). This male lateralization finding and the anterior/posterior gradient in females is consistent with Goldberg's model. The patient group however, failed to show this male lateralized and female frontal-posterior pattern of Gamma activity, suggesting suboptimal network integration in the patient group, in both males and females. PMID:11328687

  5. Gamma rays from active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Kazanas, Demosthenes

    1990-01-01

    The general properties of Active Galactic Nuclei (AGN) and quasars are reviewed with emphasis on their continuum spectral emission. Two general classes of models for the continuum are outlined and critically reviewed in view of the impending GRO (Gamma Ray Observatory) launch and observations. The importance of GRO in distinguishing between these models and in general in furthering the understanding of AGN is discussed. The very broad terms the status of the current understanding of AGN are discussed.

  6. Gamma Band Activity in the Reticular Activating System

    PubMed Central

    Urbano, Francisco J.; Kezunovic, Nebojsa; Hyde, James; Simon, Christen; Beck, Paige; Garcia-Rill, Edgar

    2012-01-01

    This review considers recent evidence showing that cells in three regions of the reticular activating system (RAS) exhibit gamma band activity, and describes the mechanisms behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine subcoeruleus nucleus dorsalis (SubCD) all fire in the beta/gamma band range when maximally activated, but no higher. The mechanisms behind this ceiling effect have been recently elucidated. We describe recent findings showing that every cell in the PPN have high-threshold, voltage-dependent P/Q-type calcium channels that are essential, while N-type calcium channels are permissive, to gamma band activity. Every cell in the Pf also showed that P/Q-type and N-type calcium channels are responsible for this activity. On the other hand, every SubCD cell exhibited sodium-dependent subthreshold oscillations. A novel mechanism for sleep–wake control based on well-known transmitter interactions, electrical coupling, and gamma band activity is described. The data presented here on inherent gamma band activity demonstrates the global nature of sleep–wake oscillation that is orchestrated by brainstem–thalamic mechanism, and questions the undue importance given to the hypothalamus for regulation of sleep–wakefulness. The discovery of gamma band activity in the RAS follows recent reports of such activity in other subcortical regions like the hippocampus and cerebellum. We hypothesize that, rather than participating in the temporal binding of sensory events as seen in the cortex, gamma band activity manifested in the RAS may help stabilize coherence related to arousal, providing a stable activation state during waking and paradoxical sleep. Most of our thoughts and actions are driven by pre-conscious processes. We speculate that continuous sensory input will induce gamma band activity in the RAS that could participate in the processes of

  7. Pedunculopontine Gamma Band Activity and Development

    PubMed Central

    Garcia-Rill, Edgar; Luster, Brennon; Mahaffey, Susan; MacNicol, Melanie; Hyde, James R.; D’Onofrio, Stasia M.; Phillips, Cristy

    2015-01-01

    This review highlights the most important discovery in the reticular activating system in the last 10 years, the manifestation of gamma band activity in cells of the reticular activating system (RAS), especially in the pedunculopontine nucleus, which is in charge of waking and rapid eye movement (REM) sleep. The identification of different cell groups manifesting P/Q-type Ca2+ channels that control waking vs. those that manifest N-type channels that control REM sleep provides novel avenues for the differential control of waking vs. REM sleep. Recent discoveries on the development of this system can help explain the developmental decrease in REM sleep and the basic rest-activity cycle. PMID:26633526

  8. Pedunculopontine Gamma Band Activity and Development.

    PubMed

    Garcia-Rill, Edgar; Luster, Brennon; Mahaffey, Susan; MacNicol, Melanie; Hyde, James R; D'Onofrio, Stasia M; Phillips, Cristy

    2015-01-01

    This review highlights the most important discovery in the reticular activating system in the last 10 years, the manifestation of gamma band activity in cells of the reticular activating system (RAS), especially in the pedunculopontine nucleus, which is in charge of waking and rapid eye movement (REM) sleep. The identification of different cell groups manifesting P/Q-type Ca(2+) channels that control waking vs. those that manifest N-type channels that control REM sleep provides novel avenues for the differential control of waking vs. REM sleep. Recent discoveries on the development of this system can help explain the developmental decrease in REM sleep and the basic rest-activity cycle. PMID:26633526

  9. Gamma Band Activity in the RAS-intracellular mechanisms

    PubMed Central

    Garcia-Rill, E.; Kezunovic, N.; D’Onofrio, S.; Luster, B.; Hyde, J.; Bisagno, V.; Urbano, F.J.

    2014-01-01

    Gamma band activity participates in sensory perception, problem solving, and memory. This review considers recent evidence showing that cells in the reticular activating system (RAS) exhibit gamma band activity, and describes the intrinsic membrane properties behind such manifestation. Specifically, we discuss how cells in the mesopontine pedunculopontine nucleus (PPN), intralaminar parafascicular nucleus (Pf), and pontine Subcoeruleus nucleus dorsalis (SubCD) all fire in the gamma band range when maximally activated, but no higher. The mechanisms involve high threshold, voltage-dependent P/Q-type calcium channels or sodium-dependent subthreshold oscillations. Rather than participating in the temporal binding of sensory events as in the cortex, gamma band activity in the RAS may participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our actions. We address three necessary next steps resulting from these discoveries, an intracellular mechanism responsible for maintaining gamma band activity based on persistent G-protein activation, separate intracellular pathways that differentiate between gamma band activity during waking vs during REM sleep, and an intracellular mechanism responsible for the dysregulation in gamma band activity in schizophrenia. These findings open several promising research avenues that have not been thoroughly explored. What are the effects of sleep or REM sleep deprivation on these RAS mechanisms? Are these mechanisms involved in memory processing during waking and/or during REM sleep? Does gamma band processing differ during waking vs REM sleep after sleep or REM sleep deprivation? PMID:24309750

  10. Enhanced gamma-ray activity from the Crab nebula

    NASA Astrophysics Data System (ADS)

    Buehler, R.; Ciprini, S.

    2016-01-01

    Preliminary LAT analysis indicates enhanced gamma-ray activity from the Crab nebula. The daily-averaged gamma-ray emission (E > 100 MeV) from the direction of the Crab Nebula has surpassed 4.0 x 10^-6 ph cm^-2 s^-1 five times in the last 12 days.

  11. Relation of gamma oscillations in scalp recordings to muscular activity.

    PubMed

    Pope, Kenneth J; Fitzgibbon, Sean P; Lewis, Trent W; Whitham, Emma M; Willoughby, John O

    2009-06-01

    We recorded scalp electrical activity before and after full neuro-muscular paralysis in 5 volunteers and determined differences due to elimination of muscular activity on several standard applications of EEG. Due to paralysis, there were reductions in 'noisiness' of the standard scalp recordings which were maximal over the peripheral scalp, not explained by abolition of movement artefact, and best accounted for by sustained EMG activity in resting individuals. There was a corresponding reduction in spectral power in the gamma range. In central leads, the extent of gamma frequency coherence during a non-time-locked mental task (1 s epochs) was reduced by paralysis, likely due to a reduction in gamma-frequency coherence in widely arising EMG signals. In a time-locked mental task (auditory oddball), evoked responses were qualitatively unaffected by paralysis but 3 of 4 induced gamma responses were obscured by EMG. PMID:19229605

  12. Active galaxies and the diffuse Gamma-Ray background

    NASA Technical Reports Server (NTRS)

    Kazanas, D.; Protheroe, R. J.

    1983-01-01

    A model for the origin of relativistic particles and gamma rays in active galactic nuclei and quasars, together with recent HEAO-1 observations of the spectra of active galaxies from 2 to 165 keV, provide the basis for a reexamination of the nature of the extragalactic gamma ray background. Active galaxies account for the observed background if their X-ray spectra steepen to E.021 above 100 keV, as observed in Cen-A, together with a further steepening to E.021 as a result of absorption of gamma rays by photon-photon pair production interactions with X-ray photons. The compactness of active galaxies required to give this steepening is consistent with estimates of their typical luminosity and radius.

  13. Gamma-irradiated bacterial preparation having anti-tumor activity

    SciTech Connect

    Vass, A.A.; Tyndall, R.L.; Terzaghi-Howe, P.

    1999-11-16

    This application describes a bacterial preparation from Pseudomonas species isolated {number{underscore}sign}15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  14. Taking into account photofission effects in gamma-activation analysis

    SciTech Connect

    Dayvdov, M.G.; Kishel'gof, V.V.; Naumov, A.P.; Trukhov, A.V.

    1986-11-01

    The authors proposed a method for calculating the effect of photofission of U and Th, which is based on the well-known laws of physics of photofission and methods for calculating the activity of fission products. The authors compared the results of numerical calculations of the gamma spectra of photofission products with the measurements performed with a Ge (Li) detector with the spectra from activated model samples of U and Th. The method developed enables calculating the coefficients of interference and is also applicable to the solution of the problems of optimization of gamma activation analysis taking into account U and Th fission.

  15. Gamma-irradiated bacterial preparation having anti-tumor activity

    DOEpatents

    Vass, Arpad A.; Tyndall, Richard L.; Terzaghi-Howe, Peggy

    1999-01-01

    A bacterial preparation from Pseudomonas species isolated #15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  16. Peptide-based, irreversible inhibitors of gamma-secretase activity.

    PubMed

    Piper, Siân C; Amtul, Zareen; Galiñanes-Garcia, Laura; Howard, Victor G; Ziani-Cherif, Chewki; McLendon, Chris; Rochette, Marjorie J; Fauq, Abdul; Golde, Todd E; Murphy, M Paul

    2003-06-01

    The characterization of the enzymes responsible for amyloid beta-peptide (Abeta) production is considered to be a primary goal towards the development of future therapeutics for the treatment of Alzheimer's disease. Inhibitors of gamma-secretase activity were critical in demonstrating that the presenilins (PSs) likely comprised at least part of the active site of the gamma-secretase enzyme complex, with two highly conserved membrane aspartates presumably acting as catalytic residues. However, whether or not these aspartates are actually the catalytic residues of the enzyme complex or are merely essential for normal PS function and/or maturation is still unknown. In this paper, we report the development of reactive inhibitors of gamma-secretase activity that are functionally irreversible. Since such inhibitors have been shown to bind catalytic residues in other aspartyl proteases (e.g., HIV protease), they might be used to determine if the transmembrane aspartates of PSs are involved directly in substrate cleavage. PMID:12763025

  17. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    SciTech Connect

    Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Kwan, J.W.

    2008-08-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  18. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    SciTech Connect

    Ludewigt, B. A.; Henestroza, E.; Kwan, J. W.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Antolak, A. J.

    2009-03-10

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the {sup 11}B(p,{gamma}){sup 12}C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the {sup 11}B(p,{gamma}){sup 12}C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB{sub 6} tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 {mu}s long pulses, and a 1% duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  19. Hippocampal theta, gamma, and theta-gamma coupling: effects of aging, environmental change, and cholinergic activation

    PubMed Central

    Jacobson, Tara K.; Howe, Matthew D.; Schmidt, Brandy; Hinman, James R.; Escabí, Monty A.

    2013-01-01

    Hippocampal theta and gamma oscillations coordinate the timing of multiple inputs to hippocampal neurons and have been linked to information processing and the dynamics of encoding and retrieval. One major influence on hippocampal rhythmicity is from cholinergic afferents. In both humans and rodents, aging is linked to impairments in hippocampus-dependent function along with degradation of cholinergic function. Cholinomimetics can reverse some age-related memory impairments and modulate oscillations in the hippocampus. Therefore, one would expect corresponding changes in these oscillations and possible rescue with the cholinomimetic physostigmine. Hippocampal activity was recorded while animals explored a familiar or a novel maze configuration. Reexposure to a familiar situation resulted in minimal aging effects or changes in theta or gamma oscillations. In contrast, exploration of a novel maze configuration increased theta power; this was greater in adult than old animals, although the deficit was reversed with physostigmine. In contrast to the theta results, the effects of novelty, age, and/or physostigmine on gamma were relatively weak. Unrelated to the behavioral situation were an age-related decrease in the degree of theta-gamma coupling and the fact that physostigmine lowered the frequency of theta in both adult and old animals. The results indicate that age-related changes in gamma and theta modulation of gamma, while reflecting aging changes in hippocampal circuitry, seem less related to aging changes in information processing. In contrast, the data support a role for theta and the cholinergic system in encoding and that hippocampal aging is related to impaired encoding of new information. PMID:23303862

  20. Cowplex usage of the gold gamma - activation analysis information

    SciTech Connect

    Degtyarev, S.I.

    1993-12-31

    A simultaneous gold assay method, evaluation of gold`s grain number and weight, and lithologic type, of ore bearing rock, is described. The basis of this method is gamma activation analysis which permits the assay of 500 grams of gold samples crushed up to 3 mm.

  1. Active galaxies and the diffuse gamma-ray background

    NASA Technical Reports Server (NTRS)

    Kazanas, D.; Protheroe, R. J.

    1983-01-01

    Active galaxies are shown to account for the observed gamma ray background radiation if a steepening of the spectra above about 100 keV is present. An analytical model is discussed in which protons undergo Fermi acceleration at a shock in a spherical accretion flow onto a massive black hole. Relativistic protons with power law spectra, nuclear interactions producing gamma rays from neutal pion decay and electrons from pion-mu meson-electron decay, with a power law spectrum above several hundred MeV, synchrotron and inverse Compton losses steepening the electron spectrum, a photon spectrum close to the pion gamma spectrum and a high-energy gamma ray spectrum steepened by photon-photon pair production interactions with X rays are covered in the model. Comparisons are made with HEAO 2 data on active galaxies, which have estimated luminosities and radii consistent with the compactness necessary for producing the steepening predicted by the model. The active galaxies spectra would be described by a spherical accretion-shock model.

  2. Gamma power is phase-locked to posterior alpha activity.

    PubMed

    Osipova, Daria; Hermes, Dora; Jensen, Ole

    2008-01-01

    Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30-70 Hz) is phase-locked to alpha oscillations (8-13 Hz) in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs) reflects a window of excitability. PMID:19098986

  3. Antioxidant activity potential of gamma irradiated carrageenan.

    PubMed

    Abad, Lucille V; Relleve, Lorna S; Racadio, Charles Darwin T; Aranilla, Charito T; De la Rosa, Alumanda M

    2013-09-01

    The antioxidant capacity of irradiated κ-, ι-, λ-carrageenans were investigated using the hydroxyl radical scavenging assay, reducing power assay and DPPH radical scavenging capacity assay. The degree of oxidative inhibition increased with increasing concentration and dose. The type of carrageenan had also an influence on its antioxidant activity which followed the order of lambda

  4. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    NASA Astrophysics Data System (ADS)

    Ludewigt, B. A.; Antolak, A. J.; Henestroza, E.; Kwan, J. W.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.

    2009-03-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,γ)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,γ)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 μs long pulses, and a 1% duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  5. The optimization of gamma spectra processing in prompt gamma neutron activation analysis (PGNAA)

    NASA Astrophysics Data System (ADS)

    Pinault, Jean-Louis; Solis, Jose

    2009-04-01

    The uncertainty of the elemental analysis is one of the major factors governing the utility of on-line Prompt Gamma Neutron Activation Analysis (PGNAA) in the blending and sorting of bulk materials. In this paper, a general method applicable to Gamma spectra processing is presented and applied to PGNAA in mineral industry. Based on the Fourier transform of spectra and their de-correlation in the Fourier space (the improvement of the conditioning of the correlation matrix), processing of overlapping of characteristic peaks minimizes the propagation of random errors, which optimizes the accuracy and decreases the detection limits of elemental analyses. In comparison with classical methods based on the linear combinations of relevant regions of spectra the improvement may be considerable, especially when several elements are interfering. The method is applied to four case stories covering both borehole logging and on-line analysis on conveyor belt of raw materials.

  6. Planetary Geochemistry Using Active Neutron and Gamma Ray Instrumentation

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    The Pulsed Neutron Generator-Gamma Ray And Neutron Detector (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth, The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asterOIds, comets and the satellites of the outer planets, Gamma-Ray Spectrometers have been incorporated into numerous orbital planetary science missions and, especially in the case of Mars Odyssey, have contributed detailed maps of the elemental composition over the entire surface of Mars, Neutron detectors have also been placed onboard orbital missions such as the Lunar Reconnaissance Orbiter and Lunar Prospector to measure the hydrogen content of the surface of the moon, The DAN in situ experiment on the Mars Science Laboratory not only includes neutron detectors, but also has its own neutron generator, However, no one has ever combined the three into one instrument PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument that can determine subsurface elemental composition without drilling. We are testing PNG-GRAND at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 m x 1 m granite structure in an empty field, We will present data from the operation of PNG-GRAND in various experimental configurations on a known sample in a geometry that is identical to that which can be achieved on a planetary surface. We will also compare the material composition results inferred from our experiments to both an independent laboratory elemental composition analysis and MCNPX computer modeling results,

  7. Analyses of Oxyanion Materials by Prompt Gamma Activation Analysis

    SciTech Connect

    Firestone, Richard B; Perry, D.L.; English, G.A.; Firestone, R.B.; Leung, K.-N.; Garabedian, G.; Molnar, G.L.; Revay, Zs.

    2008-03-24

    Prompt gamma activation analysis (PGAA) has been used to analyze metal ion oxyanion materials that have multiple applications, including medicine, materials, catalysts, and electronics. The significance for the need for accurate, highly sensitive analyses for the materials is discussed in the context of quality control of end products containing the parent element in each material. Applications of the analytical data for input to models and theoretical calculations related to the electronic and other properties of the materials are discussed.

  8. Dependency of {gamma}-secretase complex activity on the structural integrity of the bilayer

    SciTech Connect

    Zhou, Hua; Zhou, Shuxia; Walian, Peter J.; Jap, Bing K.

    2010-11-12

    Research highlights: {yields} Partial solubilization of membranes with CHAPSO can increase {gamma}-secretase activity. {yields} Completely solubilized {gamma}-secretase is inactive. {yields} Purified {gamma}-secretase regains activity after reconstitution into lipid bilayers. {yields} A broad range of detergents can be used to successfully reconstitute {gamma}-secretase. -- Abstract: {gamma}-secretase is a membrane protein complex associated with the production of A{beta} peptides that are pathogenic in Alzheimer's disease. We have characterized the activity of {gamma}-secretase complexes under a variety of detergent solubilization and reconstitution conditions, and the structural state of proteoliposomes by electron microscopy. We found that {gamma}-secretase activity is highly dependent on the physical state or integrity of the membrane bilayer - partial solubilization may increase activity while complete solubilization will abolish it. The activity of well-solubilized {gamma}-secretase can be restored to near native levels when properly reconstituted into a lipid bilayer environment.

  9. Implications of gamma band activity in the pedunculopontine nucleus.

    PubMed

    Garcia-Rill, E; Luster, B; D'Onofrio, S; Mahaffey, S; Bisagno, V; Urbano, F J

    2016-07-01

    The fact that the pedunculopontine nucleus (PPN) is part of the reticular activating system places it in a unique position to modulate sensory input and fight-or-flight responses. Arousing stimuli simultaneously activate ascending projections of the PPN to the intralaminar thalamus to trigger cortical high-frequency activity and arousal, as well as descending projections to reticulospinal systems to alter posture and locomotion. As such, the PPN has become a target for deep brain stimulation for the treatment of Parkinson's disease, modulating gait, posture, and higher functions. This article describes the latest discoveries on PPN physiology and the role of the PPN in a number of disorders. It has now been determined that high-frequency activity during waking and REM sleep is controlled by two different intracellular pathways and two calcium channels in PPN cells. Moreover, there are three different PPN cell types that have one or both calcium channels and may be active during waking only, REM sleep only, or both. Based on the new discoveries, novel mechanisms are proposed for insomnia as a waking disorder. In addition, neuronal calcium sensor protein-1 (NCS-1), which is over expressed in schizophrenia and bipolar disorder, may be responsible for the dysregulation in gamma band activity in at least some patients with these diseases. Recent results suggest that NCS-1 modulates PPN gamma band activity and that lithium acts to reduce the effects of over expressed NCS-1, accounting for its effectiveness in bipolar disorder. PMID:26597124

  10. High-energy gamma-ray observations of active galaxies

    NASA Technical Reports Server (NTRS)

    Fichtel, Carl E.

    1994-01-01

    During the period from 1992 May to early 1992 November, the Energetic Gamma-Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory obtained high-energy gamma-ray data for most of the sky. A total of 18 active galaxies have been seen with high certainty, and it is expected that more will be found in the data when a more thorough analysis is complete. All of those that have been seen are radio-loud quasars or BL Lacertae objects; most have already been identified as blazars. No Seyfert galaxies have been found thus far. If the spectra are represented as a power law in energy, spectral slopes ranging from approximately -1.7 to -2.4 are found. A wide range of z-values exits in the observed sample, eight having values in excess of 1.0. Time variations have been seen, with the timescale for a significant change being as short as days in at least one case. These results imply the existence of very large numbers of relativistic particles, probably close to the central object. Although a large extrapolation is required, their existence also suggests that these active galactic nuclei may be the source of the extragalactic cosmic rays.

  11. Prompt gamma activation analysis: An old technique made new

    SciTech Connect

    English, Jerry; Firestone, Richard; Perry, Dale; Leung, Ka-Ngo; Reijonen, Jani; Garabedian, Glenn; Bandong, Bryan; Molnar, Gabor; Revay, Zsolt

    2002-12-01

    The long list of contributors to the prompt gamma activation analysis (PGAA) project is important because it highlights the broad cast of active PGAA researchers from various facilities and backgrounds. PGAA is basically a simple process in principle that was traditionally difficult in application. It is an old technique that has for years been tied to and associated exclusively with nuclear reactor facilities, which has limited its acceptance as a general, analytical tool for identifying and quantifying elements or, more precisely, isotopes, whether radioactive or nonradioactive. Field use was not a viable option.

  12. An experimental search for gamma radiation associated with thunderstorm activity

    SciTech Connect

    Fryberger, D.

    1992-11-01

    This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and [gt] 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

  13. An experimental search for gamma radiation associated with thunderstorm activity

    SciTech Connect

    Fryberger, D.

    1992-11-01

    This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and {gt} 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

  14. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    SciTech Connect

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  15. The evaluated gamma-ray activation file (EGAF)

    SciTech Connect

    Firestone, R.B.; Molnar, G.L.; Revay, Zs.; Belgya, T.; McNabb, D.P.; Sleaford, B.W.

    2004-09-22

    The Evaluated Gamma-ray Activation File (EGAF), a new database of prompt and delayed neutron capture g-ray cross sections, has been prepared as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project to develop a ''Database of Prompt Gamma-rays from Slow Neutron Capture for Elemental Analysis.'' Recent elemental g-ray cross-section measurements performed with the guided neutron beam at the Budapest Reactor have been combined with data from the literature to produce the EGAF database. EGAF contains thermal cross sections for {approx} 35,000 prompt and delayed g-rays from 262 isotopes. New precise total thermal radiative cross sections have been derived for many isotopes from the primary and secondary gamma-ray cross sections and additional level scheme data. An IAEA TECDOC describing the EGAF evaluation and tabulating the most prominent g-rays will be published in 2004. The TECDOC will include a CD-ROM containing the EGAF database in both ENSDF and tabular formats with an interactive viewer for searching and displaying the data. The Isotopes Project, Lawrence Berkeley National Laboratory continues to maintain and update the EGAF file. These data are available on the Internet from both the IAEA and Isotopes Project websites.

  16. Minimum Detectable Activity for Tomographic Gamma Scanning System

    SciTech Connect

    Venkataraman, Ram; Smith, Susan; Kirkpatrick, J. M.; Croft, Stephen

    2015-01-01

    For any radiation measurement system, it is useful to explore and establish the detection limits and a minimum detectable activity (MDA) for the radionuclides of interest, even if the system is to be used at far higher values. The MDA serves as an important figure of merit, and often a system is optimized and configured so that it can meet the MDA requirements of a measurement campaign. The non-destructive assay (NDA) systems based on gamma ray analysis are no exception and well established conventions, such the Currie method, exist for estimating the detection limits and the MDA. However, the Tomographic Gamma Scanning (TGS) technique poses some challenges for the estimation of detection limits and MDAs. The TGS combines high resolution gamma ray spectrometry (HRGS) with low spatial resolution image reconstruction techniques. In non-imaging gamma ray based NDA techniques measured counts in a full energy peak can be used to estimate the activity of a radionuclide, independently of other counting trials. However, in the case of the TGS each “view” is a full spectral grab (each a counting trial), and each scan consists of 150 spectral grabs in the transmission and emission scans per vertical layer of the item. The set of views in a complete scan are then used to solve for the radionuclide activities on a voxel by voxel basis, over 16 layers of a 10x10 voxel grid. Thus, the raw count data are not independent trials any more, but rather constitute input to a matrix solution for the emission image values at the various locations inside the item volume used in the reconstruction. So, the validity of the methods used to estimate MDA for an imaging technique such as TGS warrant a close scrutiny, because the pair-counting concept of Currie is not directly applicable. One can also raise questions as to whether the TGS, along with other image reconstruction techniques which heavily intertwine data, is a suitable method if one expects to measure samples whose activities

  17. Gamma dose from activation of internal shields in IRIS reactor.

    PubMed

    Agosteo, Stefano; Cammi, Antonio; Garlati, Luisella; Lombardi, Carlo; Padovani, Enrico

    2005-01-01

    The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressuriser and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield. PMID:16381688

  18. Comparison of activation effects in {gamma}-ray detector materials

    SciTech Connect

    Truscott, P.R.; Evans, H.E.; Dyer, C.S.; Peerless, C.L.; Flatman, J.C.; Cosby, M.; Knight, P.; Moss, C.E.

    1996-06-01

    Activation induced by cosmic and trapped radiation in {gamma}-ray detector materials represents a significant source of background for space-based detector systems. Selection of detector materials should therefore include consideration of this background source. Results are presented from measurements of induced radioactivity in different scintillators activated either as a result of irradiation by mono-energetic protons at accelerator facilities, or flight on board the Space Shuttle. Radiation transport computer codes are used to help compare the effects observed from the scintillators, by identifying and quantifying the influence on the background spectra from more than one hundred of the radionuclides produced by spallation. For the space experiment data, the simulation results also permit determination of the contributions to detector activation from the different sources of radiation in the Shuttle cabin.

  19. Calibration of the delayed-gamma neutron activation facility

    SciTech Connect

    Ma, R.; Zhao, X.; Rarback, H.M.; Yasumura, S.; Dilmanian, F.A.; Moore, R.I.; Lo Monte, A.F.; Vodopia, K.A.; Liu, H.B.; Economos, C.D.; Nelson, M.E.; Aloia, J.F.; Vaswani, A.N.; Weber, D.A.; Pierson, R.N. Jr.; Joel, D.D.

    1996-02-01

    The delayed-gamma neutron activation facility at Brookhaven National Laboratory was originally calibrated using an anthropomorphic hollow phantom filled with solutions containing predetermined amounts of Ca. However, 99{percent} of the total Ca in the human body is not homogeneously distributed but contained within the skeleton. Recently, an artificial skeleton was designed, constructed, and placed in a bottle phantom to better represent the Ca distribution in the human body. Neutron activation measurements of an anthropomorphic and a bottle (with no skeleton) phantom demonstrate that the difference in size and shape between the two phantoms changes the total body calcium results by less than 1{percent}. To test the artificial skeleton, two small polyethylene jerry-can phantoms were made, one with a femur from a cadaver and one with an artificial bone in exactly the same geometry. The femur was ashed following the neutron activation measurements for chemical analysis of Ca. Results indicate that the artificial bone closely simulates the real bone in neutron activation analysis and provides accurate calibration for Ca measurements. Therefore, the calibration of the delayed-gamma neutron activation system is now based on the new bottle phantom containing an artificial skeleton. This change has improved the accuracy of measurement for total body calcium. Also, the simple geometry of this phantom and the artificial skeleton allows us to simulate the neutron activation process using a Monte Carlo code, which enables us to calibrate the system for human subjects larger and smaller than the phantoms used as standards. {copyright} {ital 1996 American Association of Physicists in Medicine.}

  20. Ligands for the Nuclear Peroxisome Proliferator-Activated Receptor Gamma.

    PubMed

    Sauer, Sascha

    2015-10-01

    Nuclear receptors are ligand-activated transcription factors, which represent a primary class of drug targets. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is a key player in various biological processes. PPARγ is widely known as the target protein of the thiazolidinediones for treating type 2 diabetes. Moreover, PPARγ ligands can induce anti-inflammatory and potentially additional beneficial effects. Recent mechanistic insights of PPARγ modulation give hope the next generation of efficient PPARγ-based drugs with fewer side effects can be developed. Furthermore, chemical approaches that make use of synergistic action of combinatorial ligands are promising alternatives for providing tailored medicine. Lessons learned from fine-tuning the action of PPARγ can provide avenues for efficient molecular intervention via many other nuclear receptors to combat common diseases. PMID:26435213

  1. Examination of the mechanism by which heparin antagonizes activation of a model endothelium by interferon-gamma (IFN-gamma).

    PubMed

    Douglas, M S; Rix, D A; Dark, J H; Talbot, D; Kirby, J A

    1997-03-01

    IFN-gamma increases the potential immunogenicity of vascular endothelial cells by up-regulation of intercellular adhesion molecule-1 (ICAM-1) and class I MHC antigen expression and by induction of class II MHC antigens and certain chemokines. In this study the mechanism by which the glycosaminoglycan (GAG) heparin antagonizes the activation of a model endothelium by IFN-gamma was investigated. Radioligand binding assays demonstrated that total binding of 125I-IFN-gamma to the EAhy.926 endothelial hybridoma cell line was reduced in the presence of heparin or heparan sulphate (HS); the structurally dissimilar GAG chondroitin sulphate had no effect. Treatment of the cells with chlorate, a metabolic inhibitor of GAG sulphation, was found to reduce both the subsequent binding of IFN-gamma and its ability to induce expression of class II MHC antigens. Treatment with heparinase II dramatically reduced the binding of IFN-gamma, while chondroitin ABC lyase had no effect. A cationic peptide from the C-terminal region of IFN-gamma was also found to reduce binding of intact IFN-gamma to the cells. These results appear to demonstrate that IFN-gamma is sequestered at the surface of endothelial cells by electrostatic interaction between specific basic amino acid residues and sulphated domains on HS, the most abundant endothelial GAG. This interaction is competitively inhibited by heparin, which is structurally related to HS. These observations are consistent with the model that IFN-gamma is bound by membrane-associated HS before engagement with the high-affinity receptor and signal transduction. Inhibition of the interaction between proinflammatory cytokines and membrane-associated GAG molecules may provide a mechanism for inducing clinically useful immunosuppression. PMID:9067536

  2. Minimum Detectable Activity in gamma spectrometry and its use in low level activity measurements.

    PubMed

    Done, L; Ioan, M-R

    2016-08-01

    In this paper there are described three different algorithms of Minimum Detectable Activity (MDA) calculus, and its use in high resolution gamma spectrometry. In the first part, few introductive theoretical aspects related to the MDA are presented. Further, the theory was applied to real gamma rays spectrometry measurements and the results were compared with the activities reference values. Two different gamma spectrometry systems, both of them using High Purity Germanium (HPGe) detectors, but having different efficiencies, were used. Samples having different geometries and radionuclides content were measured. The measured samples were made by dissolving of some acids containing anthropogenic radionuclides in water, obtaining a density of 1g/cm(3). Choosing this type of matrix was done because of its high homogeneity. PMID:27172893

  3. Gamma band unit activity and population responses in the pedunculopontine nucleus.

    PubMed

    Simon, Christen; Kezunovic, Nebojsa; Ye, Meijun; Hyde, James; Hayar, A; Williams, D K; Garcia-Rill, E

    2010-07-01

    The pedunculopontine nucleus (PPN) is involved in the activated states of waking and paradoxical sleep, forming part of the reticular activating system (RAS). The studies described tested the hypothesis that single unit and/or population responses of PPN neurons are capable of generating gamma band frequency activity. Whole cell patch clamp recordings (immersion chamber) and population responses (interface chamber) were conducted on 9- to 20-day-old rat brain stem slices. Regardless of cell type (I, II, or III) or type of response to the nonselective cholinergic receptor agonist carbachol (excitation, inhibition, biphasic), almost all PPN neurons fired at gamma band frequency, but no higher, when subjected to depolarizing steps (50 +/- 2 Hz, mean +/- SE). Nonaccommodating neurons fired at 18-100 Hz throughout depolarizing steps, while most accommodating neurons exhibited gamma band frequency of action potentials followed by gamma band membrane oscillations. These oscillations were blocked by the sodium channel blocker tetrodotoxin (TTX), suggesting that at least some are mediated by sodium currents. Population responses in the PPN showed that carbachol induced peaks of activation in the theta and gamma range, while glutamatergic receptor agonists induced overall increases in activity at theta and gamma frequencies, although in differing patterns. Gamma band activity appears to be a part of the intrinsic membrane properties of PPN neurons, and the population as a whole generates different patterns of gamma band activity under the influence of specific transmitters. Given sufficient excitation, the PPN may impart gamma band activation on its targets. PMID:20463196

  4. Gamma Band Unit Activity and Population Responses in the Pedunculopontine Nucleus

    PubMed Central

    Simon, Christen; Kezunovic, Nebojsa; Ye, Meijun; Hyde, James; Hayar, A.; Williams, D. K.

    2010-01-01

    The pedunculopontine nucleus (PPN) is involved in the activated states of waking and paradoxical sleep, forming part of the reticular activating system (RAS). The studies described tested the hypothesis that single unit and/or population responses of PPN neurons are capable of generating gamma band frequency activity. Whole cell patch clamp recordings (immersion chamber) and population responses (interface chamber) were conducted on 9- to 20-day-old rat brain stem slices. Regardless of cell type (I, II, or III) or type of response to the nonselective cholinergic receptor agonist carbachol (excitation, inhibition, biphasic), almost all PPN neurons fired at gamma band frequency, but no higher, when subjected to depolarizing steps (50 ± 2 Hz, mean ± SE). Nonaccommodating neurons fired at 18–100 Hz throughout depolarizing steps, while most accommodating neurons exhibited gamma band frequency of action potentials followed by gamma band membrane oscillations. These oscillations were blocked by the sodium channel blocker tetrodotoxin (TTX), suggesting that at least some are mediated by sodium currents. Population responses in the PPN showed that carbachol induced peaks of activation in the theta and gamma range, while glutamatergic receptor agonists induced overall increases in activity at theta and gamma frequencies, although in differing patterns. Gamma band activity appears to be a part of the intrinsic membrane properties of PPN neurons, and the population as a whole generates different patterns of gamma band activity under the influence of specific transmitters. Given sufficient excitation, the PPN may impart gamma band activation on its targets. PMID:20463196

  5. Germa-gamma-lactones as novel inhibitors of bacterial urease activity.

    PubMed

    Amtul, Zareen; Follmer, Cristian; Mahboob, Sumera; Atta-Ur-Rahman; Mazhar, Muhammad; Khan, Khalid M; Siddiqui, Rafat A; Muhammad, Sajjad; Kazmi, Syed A; Choudhary, Mohammad Iqbal

    2007-05-01

    Organogermanium compounds have been used as pharmacological agents. However, very few reports are available on the synthesis and antibacterial activities of lactones containing organogermaniums. The purpose of the present investigation was to determine the effects of different lactone-substituted organogermaniums on bacterial growth and their urease activity. We report synthesis of 12 germa-gamma-lactones (GeL) and their antimicrobial activities against several bacterial pathogens. Antibacterial action of all GeL was highly selective against Gram-negative bacilli, particularly Proteus mirabilis, an important pathogen infecting the urinary tract. Furthermore, our data indicate that 8-quinoline derivatives were more potent against P. mirabilis than 2-methyl-8-quinoline. For example, the beta-(o-methylphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone and beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone were maximally active with MIC(90) of 61 and 94 microM, respectively. In vitro studies demonstrated a linear correlation between antibacterial activity and inhibition of P. mirabilis urease enzyme. Further kinetic analyses revealed that inhibition occurred in a noncompetitive and concentration-dependent manner with the minimum IC(50) of 31 microM for beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone. In conclusion, these findings suggest that GeL have potential to be developed as antimicrobial agents against P. mirabilis infection. PMID:17367756

  6. Peroxisome proliferator-activated receptor gamma overexpression suppresses proliferation of human colon cancer cells

    SciTech Connect

    Tsukahara, Tamotsu; Haniu, Hisao

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer We examined the correlation between PPAR{gamma} expression and cell proliferation. Black-Right-Pointing-Pointer PPAR{gamma} overexpression reduces cell viability. Black-Right-Pointing-Pointer We show the synergistic effect of cell growth inhibition by a PPAR{gamma} agonist. -- Abstract: Peroxisome proliferator-activated receptor gamma (PPAR{gamma}) plays an important role in the differentiation of intestinal cells and tissues. Our previous reports indicate that PPAR{gamma} is expressed at considerable levels in human colon cancer cells. This suggests that PPAR{gamma} expression may be an important factor for cell growth regulation in colon cancer. In this study, we investigated PPAR{gamma} expression in 4 human colon cancer cell lines, HT-29, LOVO, DLD-1, and Caco-2. Real-time polymerase chain reaction (PCR) and Western blot analysis revealed that the relative levels of PPAR{gamma} mRNA and protein in these cells were in the order HT-29 > LOVO > Caco-2 > DLD-1. We also found that PPAR{gamma} overexpression promoted cell growth inhibition in PPAR{gamma} lower-expressing cell lines (Caco-2 and DLD-1), but not in higher-expressing cells (HT-29 and LOVO). We observed a correlation between the level of PPAR{gamma} expression and the cells' sensitivity for proliferation.

  7. Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) agonist, independently of PPAR{gamma} in human glioma cells

    SciTech Connect

    Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung; Kim, Hye Jin; Yang, Jin Mo; Ryu, Somi; Noh, Yoo Hun; Lee, Soo Hyun; Son, Meong Hi; Jung, Hye Lim; Yoo, Keon Hee; Koo, Hong Hoe; Sung, Ki Woong

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Greater than 30 {mu}M ciglitazone induces cell death in glioma cells. Black-Right-Pointing-Pointer Cell death by ciglitazone is independent of PPAR{gamma} in glioma cells. Black-Right-Pointing-Pointer CGZ induces cell death by the loss of MMP via decreased Akt. -- Abstract: Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPAR{gamma} in CGZ-induced cell death was examined. At concentrations of greater than 30 {mu}M, CGZ, a synthetic PPAR{gamma} agonist, activated caspase-3 and induced apoptosis in T98G cells. Treatment of T98G cells with less than 30 {mu}M CGZ effectively induced cell death after pretreatment with 30 {mu}M of the PPAR{gamma} antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPAR{gamma} was down-regulated cells by siRNA, lower concentrations of CGZ (<30 {mu}M) were sufficient to induce cell death, although higher concentrations of CGZ ( Greater-Than-Or-Slanted-Equal-To 30 {mu}M) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPAR{gamma}. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPAR{gamma} in glioma cells, by down-regulating Akt activity and inducing MMP collapse.

  8. Visual Cortical Gamma-Band Activity During Free Viewing of Natural Images

    PubMed Central

    Brunet, Nicolas; Bosman, Conrado A.; Roberts, Mark; Oostenveld, Robert; Womelsdorf, Thilo; De Weerd, Peter; Fries, Pascal

    2015-01-01

    Gamma-band activity in visual cortex has been implicated in several cognitive operations, like perceptual grouping and attentional selection. So far, it has been studied primarily under well-controlled visual fixation conditions and using well-controlled stimuli, like isolated bars or patches of grating. If gamma-band activity is to subserve its purported functions outside of the laboratory, it should be present during natural viewing conditions. We recorded neuronal activity with a 252-channel electrocorticographic (ECoG) grid covering large parts of the left hemisphere of 2 macaque monkeys, while they freely viewed natural images. We found that natural viewing led to pronounced gamma-band activity in the visual cortex. In area V1, gamma-band activity during natural viewing showed a clear spectral peak indicative of oscillatory activity between 50 and 80 Hz and was highly significant for each of 65 natural images. Across the ECoG grid, gamma-band activity during natural viewing was present over most of the recorded visual cortex and absent over most remaining cortex. After saccades, the gamma peak frequency slid down to 30–40 Hz at around 80 ms postsaccade, after which the sustained 50- to 80-Hz gamma-band activity resumed. We propose that gamma-band activity plays an important role during natural viewing. PMID:24108806

  9. The WISE Gamma-Ray Strip Parametrization: The Nature of the Gamma-Ray Active Galactic Nuclei of Uncertain Type

    SciTech Connect

    Massaro, F.; D'Abrusco, R.; Tosti, G.; Ajello, M.; Gasparrini, D.; Grindlay, J.E.; Smith, Howard A.; /Harvard-Smithsonian Ctr. Astrophys.

    2012-04-02

    Despite the large number of discoveries made recently by Fermi, the origins of the so called unidentified {gamma}-ray sources remain unknown. The large number of these sources suggests that among them there could be a population that significantly contributes to the isotropic gamma-ray background and is therefore crucial to understand their nature. The first step toward a complete comprehension of the unidentified {gamma}-ray source population is to identify those that can be associated with blazars, the most numerous class of extragalactic sources in the {gamma}-ray sky. Recently, we discovered that blazars can be recognized and separated from other extragalactic sources using the infrared (IR) WISE satellite colors. The blazar population delineates a remarkable and distinctive region of the IR color-color space, the WISE blazar strip. In particular, the subregion delineated by the {gamma}-ray emitting blazars is even narrower and we named it as the WISE Gamma-ray Strip (WGS). In this paper we parametrize the WGS on the basis of a single parameter s that we then use to determine if {gamma}-ray Active Galactic Nuclei of the uncertain type (AGUs) detected by Fermi are consistent with the WGS and so can be considered blazar candidates. We find that 54 AGUs out of a set 60 analyzed have IR colors consistent with the WGS; only 6 AGUs are outliers. This result implies that a very high percentage (i.e., in this sample about 90%) of the AGUs detected by Fermi are indeed blazar candidates.

  10. Reduction in cortical gamma synchrony during depolarized state of slow wave activity in mice

    PubMed Central

    Hwang, Eunjin; McNally, James M.; Choi, Jee Hyun

    2013-01-01

    EEG gamma band oscillations have been proposed to account for the neural synchronization crucial for perceptual integration. While increased gamma power and synchronization is generally observed during cognitive tasks performed during wake, several studies have additionally reported increased gamma power during sleep or anesthesia, raising questions about the characteristics of gamma oscillation during impaired consciousness and its role in conscious processing. Phase-amplitude modulation has been observed between slow wave activity (SWA, 0.5–4 Hz) and gamma oscillations during ketamine/xylazine anesthesia or sleep, showing increased gamma activity corresponding to the depolarized (ON) state of SWA. Here we divided gamma activity into its ON and OFF (hyperpolarized) state components based on the phase of SWA induced by ketamine/xylazine anesthesia and compared their power and synchrony with wake state levels in mice. We further investigated the state-dependent changes in both gamma power and synchrony across primary motor and primary somatosensory cortical regions and their interconnected thalamic regions throughout anesthesia and recovery. As observed previously, gamma power was as high as during wake specifically during the ON state of SWA. However, the synchrony of this gamma activity between somatosensory-motor cortical regions was significantly reduced compared to the baseline wake state. In addition, the somatosensory-motor cortical synchrony of gamma oscillations was reduced and restored in an anesthetic state-dependent manner, reflecting the changing depth of anesthesia. Our results provide evidence that during anesthesia changes in long-range information integration between cortical regions might be more critical for changes in consciousness than changes in local gamma oscillatory power. PMID:24379760

  11. Synthetic method and biological activities of cis-fused alpha-methylene gamma-lactones.

    PubMed

    Higuchi, Yohsuke; Shimoma, Fumito; Ando, Masayoshi

    2003-06-01

    A reliable method was developed for the synthesis of cis-fused alpha-methylene gamma-lactones via alpha-methyl gamma-lactones. Bromination of alpha-methyl gamma-lactones with LDA/CBr(4) or TMSOTf/PTAB and successive dehydrobromination with DBU or TBAF of the resulting alpha-bromo-alpha-methyl gamma-lactones gave the desired alpha-methylene gamma-lactones in high yield. This method was successfully applied to the synthesis of biologically active compounds. alpha-Methylene gamma-lactone derivatives 1c, 2c, 4c, and 17 showed cell growth inhibitory activity to P388 lymphocytic leukemia. They also showed significant activities to crop diseases. Thus, alpha-methylene gamma-lactone 1c showed preventive activity in controlling scab of apple caused by Venturia inaequalis. alpha-Methylene gamma-lactones 2c, 4c, 17, and 18 also showed significant preventive activities in controlling damping off of cucumber caused by Pythium aphanidermatum. PMID:12828467

  12. Coincidence Prompt Gamma-Ray Neutron Activation Analysis

    SciTech Connect

    R.P. gandner; C.W. Mayo; W.A. Metwally; W. Zhang; W. Guo; A. Shehata

    2002-11-10

    The normal prompt gamma-ray neutron activation analysis for either bulk or small beam samples inherently has a small signal-to-noise (S/N) ratio due primarily to the neutron source being present while the sample signal is being obtained. Coincidence counting offers the possibility of greatly reducing or eliminating the noise generated by the neutron source. The present report presents our results to date on implementing the coincidence counting PGNAA approach. We conclude that coincidence PGNAA yields: (1) a larger signal-to-noise (S/N) ratio, (2) more information (and therefore better accuracy) from essentially the same experiment when sophisticated coincidence electronics are used that can yield singles and coincidences simultaneously, and (3) a reduced (one or two orders of magnitude) signal from essentially the same experiment. In future work we will concentrate on: (1) modifying the existing CEARPGS Monte Carlo code to incorporate coincidence counting, (2) obtaining coincidence schemes for 18 or 20 of the common elements in coal and cement, and (3) optimizing the design of a PGNAA coincidence system for the bulk analysis of coal.

  13. O-GlcNAc modification of PPAR{gamma} reduces its transcriptional activity

    SciTech Connect

    Ji, Suena; Park, Sang Yoon; Roth, Juergen; Kim, Hoe Suk; Cho, Jin Won

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer We found that PPAR{gamma} is modified by O-GlcNAc in 3T3-L1 adipocytes. Black-Right-Pointing-Pointer The Thr54 of PPAR{gamma}1 is the major O-GlcNAc site. Black-Right-Pointing-Pointer Transcriptional activity of PPAR{gamma}1 was decreased on treatment with the OGA inhibitor. -- Abstract: The peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}), a member of the nuclear receptor superfamily, is a key regulator of adipogenesis and is important for the homeostasis of the adipose tissue. The {beta}-O-linked N-acetylglucosamine (O-GlcNAc) modification, a posttranslational modification on various nuclear and cytoplasmic proteins, is involved in the regulation of protein function. Here, we report that PPAR{gamma} is modified by O-GlcNAc in 3T3-L1 adipocytes. Mass spectrometric analysis and mutant studies revealed that the threonine 54 of the N-terminal AF-1 domain of PPAR{gamma} is the major O-GlcNAc site. Transcriptional activity of wild type PPAR{gamma} was decreased 30% by treatment with the specific O-GlcNAcase (OGA) inhibitor, but the T54A mutant of PPAR{gamma} did not respond to inhibitor treatment. In 3T3-L1 cells, an increase in O-GlcNAc modification by OGA inhibitor reduced PPAR{gamma} transcriptional activity and terminal adipocyte differentiation. Our results suggest that the O-GlcNAc state of PPAR{gamma} influences its transcriptional activity and is involved in adipocyte differentiation.

  14. Controlling nuclear JAKs and STATs for specific gene activation by IFN{gamma}

    SciTech Connect

    Noon-Song, Ezra N.; Ahmed, Chulbul M.; Dabelic, Rea; Canton, Johnathan; Johnson, Howard M.

    2011-07-08

    Highlights: {yields} Gamma interferon (IFN{gamma}) and its receptor subunit, IFNGR1, interact with the promoter region of IFN{gamma}-associated genes along with transcription factor STAT1{alpha}. {yields} We show that activated Janus kinases pJAK2 and pJAK1 also associate with IFNGR1 in the nucleus. {yields} The activated Janus kinases are responsible for phosphorylation of tyrosine 41 on histone H3, an important epigenetic event for specific gene activation. -- Abstract: We previously showed that gamma interferon (IFN{gamma}) and its receptor subunit, IFNGR1, interacted with the promoter region of IFN{gamma}-activated genes along with transcription factor STAT1{alpha}. Recent studies have suggested that activated Janus kinases pJAK2 and pJAK1 also played a role in gene activation by phosphorylation of histone H3 on tyrosine 41. This study addresses the question of the role of activated JAKs in specific gene activation by IFN{gamma}. We carried out chromatin immunoprecipitation (ChIP) followed by PCR in IFN{gamma} treated WISH cells and showed association of pJAK1, pJAK2, IFNGR1, and STAT1 on the same DNA sequence of the IRF-1 gene promoter. The {beta}-actin gene, which is not activated by IFN{gamma}, did not show this association. The movement of activated JAK to the nucleus and the IRF-1 promoter was confirmed by the combination of nuclear fractionation, confocal microscopy and DNA precipitation analysis using the biotinylated GAS promoter. Activated JAKs in the nucleus was associated with phosphorylated tyrosine 41 on histone H3 in the region of the GAS promoter. Unphosphorylated JAK2 was found to be constitutively present in the nucleus and was capable of undergoing activation in IFN{gamma} treated cells, most likely via nuclear IFNGR1. Association of pJAK2 and IFNGR1 with histone H3 in IFN{gamma} treated cells was demonstrated by histone H3 immunoprecipitation. Unphosphorylated STAT1 protein was associated with histone H3 of untreated cells. IFN{gamma

  15. Effects of Muslims praying (Salat) on EEG gamma activity.

    PubMed

    Doufesh, Hazem; Ibrahim, Fatimah; Safari, Mohammad

    2016-08-01

    This study investigates the difference of mean gamma EEG power between actual and mimic Salat practices in twenty healthy Muslim subjects. In the actual Salat practice, the participants were asked to recite and performing the physical steps in all four stages of Salat; whereas in the mimic Salat practice, they were instructed to perform only the physical steps without recitation. The gamma power during actual Salat was statistically higher than during mimic Salat in the frontal and parietal regions in all stages. In the actual Salat practice, the left hemisphere exhibited significantly higher mean gamma power in all cerebral regions and all stages, except the central-parietal region in the sitting position, and the frontal area in the bowing position. Increased gamma power during Salat, possibly related to an increase in cognitive and attentional processing, supports the concept of Salat as a focus attention meditation. PMID:27502795

  16. Activation of AMPK alpha and gamma-isoform complexes in the intact ischemic rat heart

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AMP-activated protein kinase (AMPK) plays a key role in modulating cellular metabolic processes. AMPK, a serine-threonine kinase, is a heterotrimeric complex of catalytic alpha-subunits and regulatory beta- and gamma-subunits with multiple isoforms. Mutations in the cardiac gamma(2)-isoform have bee...

  17. 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

  18. Activation of PPAR{gamma} is not involved in butyrate-induced epithelial cell differentiation

    SciTech Connect

    Ulrich, S.; Waechtershaeuser, A.; Loitsch, S.; Knethen, A. von; Bruene, B.; Stein, J. . E-mail: j.stein@em.uni-frankfurt.de

    2005-10-15

    Histone deacetylase-inhibitors affect growth and differentiation of intestinal epithelial cells by inducing expression of several transcription factors, e.g. Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) or vitamin D receptor (VDR). While activation of VDR by butyrate mainly seems to be responsible for cellular differentiation, the activation of PPAR{gamma} in intestinal cells remains to be elucidated. The aim of this study was to determine the role of PPAR{gamma} in butyrate-induced cell growth inhibition and differentiation induction in Caco-2 cells. Treatment with PPAR{gamma} ligands ciglitazone and BADGE (bisphenol A diglycidyl) enhanced butyrate-induced cell growth inhibition in a dose- and time-dependent manner, whereas cell differentiation was unaffected after treatment with PPAR{gamma} ligands rosiglitazone and MCC-555. Experiments were further performed in dominant-negative PPAR{gamma} mutant cells leading to an increase in cell growth whereas butyrate-induced cell differentiation was again unaffected. The present study clearly demonstrated that PPAR{gamma} is involved in butyrate-induced inhibition of cell growth, but seems not to play an essential role in butyrate-induced cell differentiation.

  19. Activities of gamma-glutamyl transpeptidase and erythrocyte glutathione dependent enzymes in nasopharyngeal carcinoma patients and normal controls.

    PubMed

    Ngah, W Z; Shamaan, N A; Said, M H; Azhar, M T

    1993-01-01

    Plasma gamma-glutamyltranspeptidase (gamma-GT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were determined in normal and nasopharyngeal carcinoma (NPC) patients. No difference in enzyme activities was observed in the three major races of the Malaysian population, i.e. Malay, Chinese and Indian patients. However, plasma gamma-GT, erythrocyte glutathione S-transferase (GST) and GPx activities were significantly increased in all NPC patients, while GR activity remained unchanged. Patients with elevated plasma gamma-GT activities also had increased GST and GPx activities. Plasma gamma-GT and GPx activities were then found to be affected by treatment. Patients with plasma gamma-GT activity greater than 70 IU/l had very poor prognoses but patients with decreased gamma-GT activities were found to be in remission. PMID:8105826

  20. Prompt Gamma-Ray Neutron Activation Analysis (PGNAA) for Elemental Analysis

    SciTech Connect

    Robin P. Gardner

    2006-04-11

    This research project was to improve the prompt gamma-ray neutron activation analysis (PGNAA) measurement approach for bulk analysis, oil well logging, and small sample thermal enutron bean applications.

  1. Enhanced Stimulus-Induced Gamma Activity in Humans during Propofol-Induced Sedation

    PubMed Central

    Diukova, Ana; Singh, Krish; Hall, Judith; Wise, Richard

    2013-01-01

    Stimulus-induced gamma oscillations in the 30–80 Hz range have been implicated in a wide number of functions including visual processing, memory and attention. While occipital gamma-band oscillations can be pharmacologically modified in animal preparations, pharmacological modulation of stimulus-induced visual gamma oscillations has yet to be demonstrated in non-invasive human recordings. Here, in fifteen healthy humans volunteers, we probed the effects of the GABAA agonist and sedative propofol on stimulus-related gamma activity recorded with magnetoencephalography, using a simple visual grating stimulus designed to elicit gamma oscillations in the primary visual cortex. During propofol sedation as compared to the normal awake state, a significant 60% increase in stimulus-induced gamma amplitude was seen together with a 94% enhancement of stimulus-induced alpha suppression and a simultaneous reduction in the amplitude of the pattern-onset evoked response. These data demonstrate, that propofol-induced sedation is accompanied by increased stimulus-induced gamma activity providing a potential window into mechanisms of gamma-oscillation generation in humans. PMID:23483920

  2. Specification of High Activity Gamma-Ray Sources.

    ERIC Educational Resources Information Center

    International Commission on Radiation Units and Measurements, Washington, DC.

    The report is concerned with making recommendations for the specifications of gamma ray sources, which relate to the quantity of radioactive material and the radiation emitted. Primary consideration is given to sources in teletherapy and to a lesser extent those used in industrial radiography and in irradiation units used in industry and research.…

  3. Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination.

    PubMed

    Morgan, Helen M; Muthukumaraswamy, Suresh D; Hibbs, Carina S; Shapiro, Kimron L; Bracewell, R Martyn; Singh, Krish D; Linden, David E J

    2011-12-01

    The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80-100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination. PMID:21940605

  4. IP receptor-dependent activation of PPAR{gamma} by stable prostacyclin analogues

    SciTech Connect

    Falcetti, Emilia; Flavell, David M.; Staels, Bart; Tinker, Andrew; Haworth, Sheila G.; Clapp, Lucie H. . E-mail: l.clapp@ucl.ac.uk

    2007-09-07

    Stable prostacyclin analogues can signal through cell surface IP receptors or by ligand binding to nuclear peroxisome proliferator-activated receptors (PPARs). So far these agents have been reported to activate PPAR{alpha} and PPAR{delta} but not PPAR{gamma}. Given PPAR{gamma} agonists and prostacyclin analogues both inhibit cell proliferation, we postulated that the IP receptor might elicit PPAR{gamma} activation. Using a dual luciferase reporter gene assay in HEK-293 cells stably expressing the IP receptor or empty vector, we found that prostacyclin analogues only activated PPAR{gamma} in the presence of the IP receptor. Moreover, the novel IP receptor antagonist, RO1138452, but not inhibitors of the cyclic AMP pathway, prevented activation. Likewise, the anti-proliferative effects of treprostinil observed in IP receptor expressing cells, were partially inhibited by the PPAR{gamma} antagonist, GW9662. We conclude that PPAR{gamma} is activated through the IP receptor via a cyclic AMP-independent mechanism and contributes to the anti-growth effects of prostacyclin analogues.

  5. Membrane Potential Dynamics of Spontaneous and Visually Evoked Gamma Activity in V1 of Awake Mice

    PubMed Central

    Perrenoud, Quentin; Pennartz, Cyriel M. A.; Gentet, Luc J.

    2016-01-01

    Cortical gamma activity (30–80 Hz) is believed to play important functions in neural computation and arises from the interplay of parvalbumin-expressing interneurons (PV) and pyramidal cells (PYRs). However, the subthreshold dynamics underlying its emergence in the cortex of awake animals remain unclear. Here, we characterized the intracellular dynamics of PVs and PYRs during spontaneous and visually evoked gamma activity in layers 2/3 of V1 of awake mice using targeted patch-clamp recordings and synchronous local field potentials (LFPs). Strong gamma activity patterned in short bouts (one to three cycles), occurred when PVs and PYRs were depolarizing and entrained their membrane potential dynamics regardless of the presence of visual stimulation. PV firing phase locked unconditionally to gamma activity. However, PYRs only phase locked to visually evoked gamma bouts. Taken together, our results indicate that gamma activity corresponds to short pulses of correlated background synaptic activity synchronizing the output of cortical neurons depending on external sensory drive. PMID:26890123

  6. Transcriptional activation of peroxisome proliferator-activated receptor-{gamma} requires activation of both protein kinase A and Akt during adipocyte differentiation

    SciTech Connect

    Kim, Sang-pil; Ha, Jung Min; Yun, Sung Ji; Kim, Eun Kyoung; Chung, Sung Woon; Hong, Ki Whan; Kim, Chi Dae; Bae, Sun Sik

    2010-08-13

    Research highlights: {yields} Elevated cAMP activates both PKA and Epac. {yields} PKA activates CREB transcriptional factor and Epac activates PI3K/Akt pathway via Rap1. {yields} Akt modulates PPAR-{gamma} transcriptional activity in concert with CREB. -- Abstract: Peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) is required for the conversion of pre-adipocytes. However, the mechanism underlying activation of PPAR-{gamma} is unclear. Here we showed that cAMP-induced activation of protein kinase A (PKA) and Akt is essential for the transcriptional activation of PPAR-{gamma}. Hormonal induction of adipogenesis was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), by a protein kinase A (PKA) inhibitor (H89), and by a Rap1 inhibitor (GGTI-298). Transcriptional activity of PPAR-{gamma} was markedly enhanced by 3-isobutyl-1-methylxanthine (IBMX), but not insulin and dexamethasone. In addition, IBMX-induced PPAR-{gamma} transcriptional activity was blocked by PI3K/Akt, PKA, or Rap1 inhibitors. 8-(4-Chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT-2'-O-Me-cAMP) which is a specific agonist for exchanger protein directly activated by cAMP (Epac) significantly induced the activation of Akt. Furthermore, knock-down of Akt1 markedly attenuated PPAR-{gamma} transcriptional activity. These results indicate that both PKA and Akt signaling pathways are required for transcriptional activation of PPAR-{gamma}, suggesting post-translational activation of PPAR-{gamma} might be critical step for adipogenic gene expression.

  7. Gamma irradiation improves the antioxidant activity of Aloe vera (Aloe barbadensis miller) extracts

    NASA Astrophysics Data System (ADS)

    Mi Lee, Eun; Bai, Hyoung-Woo; Sik Lee, Seung; Hyun Hong, Sung; Cho, Jae-Young; Yeoup Chung, Byung

    2012-08-01

    Aloe has been widely used in food products, pharmaceuticals, and cosmetics because of its aromatic and therapeutic properties. In the present study, the ethanolic extracts of aloe gel were gamma-irradiated from 10 to 100 kGy. After gamma irradiation, the color of the ethanolic extracts of aloe gel changed to red; this color persisted up to 40 kGy but disappeared above 50 kGy. Liquid chromatography/mass spectrometry analysis demonstrated the production of a new, unknown compound (m/z=132) after gamma irradiation of the ethanolic extracts of aloe gel. The amount of this unknown compound increased with increasing irradiation up to 80 kGy, and it was degraded at 100 kGy. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by the 1,1-diphenyl-2-picrylhydrazyl-radical scavenging capacity. The antioxidant activity of aloe extract was dramatically increased from 53.9% in the non-irradiated sample to 92.8% in the sample irradiated at 40 kGy. This strong antioxidant activity was retained even at 100 kGy. These results indicate that gamma irradiation of aloe extract can enhance its antioxidant activity through the formation of a new compound. Based on these results, increased antioxidant activity of aloe extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  8. Interferon-gamma induces the synthesis and activation of cytosolic phospholipase A2.

    PubMed Central

    Wu, T; Levine, S J; Lawrence, M G; Logun, C; Angus, C W; Shelhamer, J H

    1994-01-01

    Both IFN-alpha/beta and IFN-gamma have recently been demonstrated to induce a rapid but transient activation of phospholipase A2 (PLA2) in BALB/c 3T3 fibroblasts and a human neuroblastoma cell line. We report that IFN-gamma induces the synthesis and prolonged activation of cytosolic phospholipase A2 (cPLA2) in a human bronchial epithelial cell line (BEAS 2B). Treatment of the cells with IFN-gamma (300 U/ml) increased the release of [3H]arachidonic acid (AA) from prelabeled cells with a maximal effect at 12 h after stimulation. The increased [3H]AA release was inhibited by the PLA2 inhibitor p-bromophenacyl bromide (10(-5) M). Calcium ionophore A23187 (10(-5) M) further increased the [3H]AA release from the IFN-gamma-treated cells. Subcellular enzyme activity assay revealed that IFN-gamma increased PLA2 activity in both the cytosol and membrane fractions with a translocation of the cPLA2 to cell membranes in a Ca(2+)-free cell lysing buffer. Treatment with IFN-gamma also induced the release of 15-HETE, an arachidonic acid metabolite. Immunoblot showed that IFN-gamma induced the synthesis of cPLA2 protein. Nuclear run-on assay demonstrated that IFN-gamma initiated cPLA2 gene transcription within 15 min, and this effect was sustained at 4 h and returned to near control level at 12 h. The cPLA2 mRNA level was assayed by reverse transcription and PCR. IFN-gamma was found to increase the cPLA2 mRNA after 2-24 h treatment. Furthermore, the IFN-gamma induced cPLA2 mRNA increase was blocked by inhibitors of protein kinase C and calcium/calmodulin-dependent protein kinases, suggesting the involvement of these protein kinases in IFN-gamma-induced gene expression of cPLA2. This study shows that IFN-gamma induces the synthesis and prolonged activation of cPLA2. Images PMID:8113394

  9. Structural recognition and functional activation of Fc[gamma]R by innate pentraxins

    SciTech Connect

    Lu, Jinghua; Marnell, Lorraine L.; Marjon, Kristopher D.; Mold, Carolyn; Du Clos, Terry W.; Sun, Peter D.

    2009-10-05

    Pentraxins are a family of ancient innate immune mediators conserved throughout evolution. The classical pentraxins include serum amyloid P component (SAP) and C-reactive protein, which are two of the acute-phase proteins synthesized in response to infection. Both recognize microbial pathogens and activate the classical complement pathway through C1q. More recently, members of the pentraxin family were found to interact with cell-surface Fc{gamma} receptors (Fc{gamma}R) and activate leukocyte-mediated phagocytosis. Here we describe the structural mechanism for pentraxin's binding to Fc{gamma}R and its functional activation of Fc{gamma}R-mediated phagocytosis and cytokine secretion. The complex structure between human SAP and Fc{gamma}RIIa reveals a diagonally bound receptor on each SAP pentamer with both D1 and D2 domains of the receptor contacting the ridge helices from two SAP subunits. The 1:1 stoichiometry between SAP and Fc{gamma}RIIa infers the requirement for multivalent pathogen binding for receptor aggregation. Mutational and binding studies show that pentraxins are diverse in their binding specificity for Fc{gamma}R isoforms but conserved in their recognition structure. The shared binding site for SAP and IgG results in competition for Fc{gamma}R binding and the inhibition of immune-complex-mediated phagocytosis by soluble pentraxins. These results establish antibody-like functions for pentraxins in the Fc{gamma}R pathway, suggest an evolutionary overlap between the innate and adaptive immune systems, and have new therapeutic implications for autoimmune diseases.

  10. Peroxisome proliferator-activated receptor-{gamma} as a regulator of lung inflammation and repair.

    PubMed

    Standiford, Theodore J; Keshamouni, Venkateshwar G; Reddy, Raju C

    2005-01-01

    Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily that regulate the expression of genes involved in a variety of biological processes, including lipid metabolism and insulin sensitivity. Members of the PPAR family-in particular, PPAR-gamma-have more recently been shown to broadly regulate inflammatory and reparative responses. PPAR-gamma is expressed in both alveolar macrophages and neutrophils, and the ligand-dependent activation of this receptor results in suppression of leukocyte effector responses, including cytokine production, the elaboration of reactive oxygen and nitrogen species, and migratory responses. In addition to antiinflammatory effects, PPAR-gamma regulates diverse processes in lung stromal/parenchymal cells, including cell growth, differentiation, and apoptosis. Studies examining in vivo effects of PPAR-gamma have produced complex and at times conflicting results. However, evidence to date generally suggests that PPAR-gamma functions to dampen inflammation and injury in various animal models of acute lung injury. PPAR-gamma may also play an important role in other inflammatory/immune lung diseases, including ischemia-reperfusion injury, allergic airway inflammation, and cancer. The role of PPAR-gamma in human lung diseases, including acute lung injury, requires further study. PMID:16222042

  11. Fermi-LAT detection of ongoing gamma-ray activity from the new gamma-ray source Fermi J1654-1055 (PMN J1632-1052)

    NASA Astrophysics Data System (ADS)

    Kocevski, D.; Ajello, M.; Buson, S.; Buehler, R.; Giomi, M.

    2016-02-01

    During the week between February 8 and 15, 2016, the Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, observed gamma-ray activity from a new transient source, Fermi J1654-1055.

  12. Implementation of gamma-ray instrumentation for solid solar system bodies using neutron activation method

    NASA Astrophysics Data System (ADS)

    Litvak, M. L.; Golovin, D. V.; Jun, I.; Kozyrev, A. S.; Mitrofanov, I. G.; Sanin, A. B.; Shvetsov, V. N.; Timoshenko, G. N.; Zontikov, A.

    2016-06-01

    In this paper we present the results of ground tests performed with a flight model and with industry prototypes of passive and active gamma ray spectrometers with the objective of understanding their capability to distinguish the elemental composition of planetary bodies in the solar system. The gamma instrumentation, which was developed for future space missions was used in the measurements at a special ground test facility where a simulant of planetary material was fabricated with a martian-like composition. In this study, a special attention was paid to the gamma lines from activation reaction products generated by a pulsed neutron generator. The instrumentation was able to detect and identify gamma lines attributed to O, Na, Mg, Al, Si, K, Ca and Fe.

  13. Intracellular mechanisms modulating gamma band activity in the pedunculopontine nucleus (PPN).

    PubMed

    Luster, Brennon R; Urbano, Francisco J; Garcia-Rill, Edgar

    2016-06-01

    The pedunculopontine nucleus is a part of the reticular activating system, and is active during waking and REM sleep. Previous results showed that all PPN cells tested fired maximally at gamma frequencies when depolarized. This intrinsic membrane property was shown to be mediated by high-threshold N- and P/Q-type Ca(2+) channels. Recent studies show that the PPN contains three independent populations of neurons which can generate gamma band oscillations through only N-type channels, only P/Q-type channels, or both N- and P/Q-type channels. This study investigated the intracellular mechanisms modulating gamma band activity in each population of neurons. We performed in vitro patch-clamp recordings of PPN neurons from Sprague-Dawley rat pups, and applied 1-sec ramps to induce intrinsic membrane oscillations. Our results show that there are two pathways modulating gamma band activity in PPN neurons. We describe populations of neurons mediating gamma band activity through only N-type channels and the cAMP/PKA pathway (presumed "REM-on" neurons), through only P/Q-type channels and the CaMKII pathway (presumed "Wake-on" neurons), and a third population which can mediate gamma activity through both N-type channels and cAMP/PK and P/Q-type channels and CaMKII (presumed "Wake/REM-on" neurons). These novel results suggest that PPN gamma oscillations are modulated by two independent pathways related to different Ca(2+) channel types. PMID:27354537

  14. PPAR-gamma activation fails to provide myocardial protection in ischemia and reperfusion in pigs.

    PubMed

    Xu, Ya; Gen, Michael; Lu, Li; Fox, Jennifer; Weiss, Sara O; Brown, R Dale; Perlov, Daniel; Ahmad, Hasan; Zhu, Peili; Greyson, Clifford; Long, Carlin S; Schwartz, Gregory G

    2005-03-01

    Peroxisome proliferator-activated receptor (PPAR)-gamma modulates substrate metabolism and inflammatory responses. In experimental rats subjected to myocardial ischemia-reperfusion (I/R), thiazolidinedione PPAR-gamma activators reduce infarct size and preserve left ventricular function. Troglitazone is the only PPAR-gamma activator that has been shown to be protective in I/R in large animals. However, because troglitazone contains both alpha-tocopherol and thiazolidinedione moieties, whether PPAR-gamma activation per se is protective in myocardial I/R in large animals remains uncertain. To address this question, 56 pigs were treated orally for 8 wk with troglitazone (75 mg x kg(-1) x day(-1)), rosiglitazone (3 mg x kg(-1) x day(-1)), or alpha-tocopherol (73 mg x kg(-1) x day(-1), equimolar to troglitazone dose) or received no treatment. Pigs were then anesthetized and subjected to 90 min of low-flow regional myocardial ischemia and 90 min of reperfusion. Myocardial expression of PPAR-gamma, determined by ribonuclease protection assay, increased with troglitazone and rosiglitazone compared with no treatment. Rosiglitazone had no significant effect on myocardial contractile function (Frank-Starling relations), substrate uptake, or expression of proinflammatory cytokines during I/R compared with untreated pigs. In contrast, preservation of myocardial contractile function and lactate uptake were greater and cytokine expression was attenuated in pigs treated with troglitazone or alpha-tocopherol compared with untreated pigs. Multivariate analysis indicated that presence of an alpha-tocopherol, but not a thiazolidinedione, moiety in the test compound was significantly related to greater contractile function and lactate uptake and lower cytokine expression during I/R. We conclude that PPAR-gamma activation is not protective in a porcine model of myocardial I/R. Protective effects of troglitazone are attributable to its alpha-tocopherol moiety. These findings, in

  15. Protein tyrosine kinase activity is essential for Fc gamma receptor-mediated intracellular killing of Staphylococcus aureus by human monocytes.

    PubMed Central

    Zheng, L; Nibbering, P H; Zomerdijk, T P; van Furth, R

    1994-01-01

    Our previous study revealed that the intracellular killing of Staphylococcus aureus by human monocytes after cross-linking Fc gamma receptor I (Fc gamma RI) or Fc gamma RII is a phospholipase C (PLC)-dependent process. The aim of the present study was to investigate whether protein tyrosine kinase (PTK) activity plays a role in the Fc gamma R-mediated intracellular killing of bacteria and activation of PLC in these cells. The results showed that phagocytosis of bacteria by monocytes was not affected by the PTK inhibitors genistein and tyrphostin-47. The intracellular killing of S. aureus by monocytes after cross-linking Fc gamma RII or Fc gamma RII with anti-Fc gamma R monoclonal antibody and a bridging antibody or with human immunoglobulin G (IgG) was inhibited by these compounds in a dose-dependent fashion. The production of O2- by monocytes after stimulation with IgG or IgG-opsonized S. aureus was almost completely blocked by the PTK inhibitor. These results indicate that inhibition of PTK impairs the oxygen-dependent bactericidal mechanisms of monocytes. Genistein and tyrphostin-47, which do not affect the enzymatic activity of purified PLC, prevented activation of PLC after cross-linking Fc gamma RI or Fc gamma RII, measured as an increase in the intracellular inositol 1,4,5-trisphosphate concentration. Cross-linking Fc gamma RI or Fc gamma RII induced rapid tyrosine phosphorylation of several proteins in monocytes, one of which was identified as PLC-gamma 1, and the phosphorylation could be completely blocked by PTK inhibitors, leading to the conclusion that activation of PLC after cross-linking Fc gamma R in monocytes is regulated by PTK activity. Together, these results demonstrate that PTK activity is essential for the activation of PLC which is involved in the Fc gamma R-mediated intracellular killing of S. aureus by human monocytes. Images PMID:7927687

  16. Two Active States of the Narrow-Line Gamma-Ray-Loud AGN GB 1310 + 487

    NASA Technical Reports Server (NTRS)

    Sokolovsky, K. V.; Schinzel, F. K.; Tanaka, Y. T.; Abolmasov, P. K.; Angelakis, E.; Bulgarelli, A.; Carrasco, L.; Cenko, S. B.; Cheung, C. C.; Clubb, K. I.; D'Ammando, F.; Escande, L.; Fegan, S. J.; Filippenko, A. V.; Finke, J. D.; Fuhrmann, L.; Fukazawa, Y.; Hays, E.; Healey, S. E.; Ikejiri, Y.; Itoh, R.; Kawabata, K. S.; Komatsu, T.; Kovalev, Yu. A.; Kovalev, Y. Y.; Krichbaum, T. P.

    2014-01-01

    Context. Previously unremarkable, the extragalactic radio source GB1310 487 showed gamma-ray flare on 2009 November 18, reaching a daily flux of approximately 10(exp -6) photons cm(exp -2) s(exp -1) at energies E greater than 100MeV and became one of the brightest GeV sources for about two weeks. Its optical spectrum shows strong forbidden-line emission while lacking broad permitted lines, which is not typical for a blazar. Instead, the spectrum resembles those of narrow emission-line galaxies. Aims. We investigate changes in the object's radio-to-GeV spectral energy distribution (SED) during and after the prominent gamma-ray flare with the aim of determining the nature of the object and of constraining the origin of the variable high-energy emission. Methods. The data collected by the Fermi and AGILE satellites at gamma-ray energies; Swift at X-ray and ultraviolet (UV); the Kanata, NOT, and Keck telescopes at optical; OAGH and WISE at infrared (IR); and IRAM30m, OVRO 40m, Effelsberg 100m, RATAN-600, and VLBA at radio are analyzed together to trace the SED evolution on timescales of months. Results. The gamma-ray radio-loud narrow-line active galactic nucleus (AGN) is located at redshift z = 0.638. It shines through an unrelated foreground galaxy at z = 0.500. The AGN light is probably amplified by gravitational lensing. The AGN SED shows a two-humped structure typical of blazars and gamma-ray-loud narrow-line Seyfert 1 galaxies, with the high-energy (inverse-Compton) emission dominating by more than an order of magnitude over the low-energy (synchrotron) emission during gamma-ray flares. The difference between the two SED humps is smaller during the low-activity state. Fermi observations reveal a strong correlation between the gamma-ray flux and spectral index, with the hardest spectrum observed during the brightest gamma-ray state. The gamma-ray flares occurred before and during a slow rising trend in the radio, but no direct association between gamma-ray and

  17. Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex

    PubMed Central

    Lu, Yao; Truccolo, Wilson; Wagner, Fabien B.; Vargas-Irwin, Carlos E.; Ozden, Ilker; Zimmermann, Jonas B.; May, Travis; Agha, Naubahar S.; Wang, Jing

    2015-01-01

    Transient gamma-band (40–80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions. PMID:25761956

  18. Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex.

    PubMed

    Lu, Yao; Truccolo, Wilson; Wagner, Fabien B; Vargas-Irwin, Carlos E; Ozden, Ilker; Zimmermann, Jonas B; May, Travis; Agha, Naubahar S; Wang, Jing; Nurmikko, Arto V

    2015-06-01

    Transient gamma-band (40-80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions. PMID:25761956

  19. Spontaneous fast gamma activity in the septal hippocampal region correlates with spatial learning in humans.

    PubMed

    Cornwell, B R; Overstreet, C; Grillon, C

    2014-03-15

    Hippocampal neuronal populations exhibit multiple kinds of activity patterns, from the dominant theta rhythm during active exploration to high-frequency ripple-like activity during periods of relative inactivity. In animals, evidence is rapidly accruing that these high-frequency ripple activity patterns subserve retention of spatial learning performance. In a translational effort to address the possible function of offline hippocampal processes in humans, we measured spontaneous gamma activity during an awake rest period within a virtual spatial learning context. Whole-head magnetoencephalographic (MEG) recordings were taken while healthy participants (N=24) quietly rested (eyes open) between encoding and retrieval phases of a hippocampal-dependent virtual Morris water maze task. Results are that fast gamma activity (80-140 Hz) in the septal or posterior region of the hippocampus (bilaterally) was positively correlated across participants with subsequent within-session spatial learning rate. Fast gamma did not predict initial retrieval performance following rest, failing to provide evidence of a direct link between spontaneous high-frequency activity patterns during awake rest and consolidation of previous spatial memories. The findings nevertheless are consistent with a prospective role for offline human hippocampal processes in spatial learning and indicate that higher spontaneous gamma activity in the septal hippocampal region is related to faster updating of spatial knowledge in familiar virtual surroundings. PMID:24388977

  20. Renewed gamma-ray activity of the Blazar 3C 454.3 detected by AGILE

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Parmiggiani, N.; Fioretti, V.; Zoli, A.; Lucarelli, F.; Verrecchia, F.; Pittori, C.; Vercellone, S.; Piano, G.; Munar-Adrover, P.; Tavani, M.; Donnarumma, I.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-06-01

    The AGILE satellite is detecting a significant enhancement in gamma-ray activity from the FSRQ 3C 454.3 (known as 1AGLR J2254+1609) since the recent AGILE ATel #9157, and the optical activity reported in ATel #9150.

  1. Induction of indoleamine 2,3-dioxygenase: a mechanism of the antitumor activity of interferon. gamma

    SciTech Connect

    Ozaki, Y.; Edelstein, M.P.; Duch, D.S.

    1988-02-01

    The antiproliferative effects of interferon ..cap alpha.. (IFN-..cap alpha..) and interferon ..gamma.. (IFN-..gamma..) were found to be cell-dependent. Among the human cell lines examined, IFN-..gamma.. had a greater antiproliferative effect against cell lines that exhibited induction of indoleamine 2,3-dioxygenase, such as the KB oral carcinoma or WiDr colon adenocarcinoma, than against those that lacked the enzyme activity, such as the SW480 colon adenocarcinoma of NCI-H128 small-cell lung carcinoma. Induction of this dioxygenase showed a clear temporal relationship with increased metabolism of L-tryptophan and the depletion of this amino acid in the culture medium. While 70-80% of L-tryptophan remained in the medium of IFN-..cap alpha..- or vehicle-treated cells, virtually all of this amino acid was depleted in the medium of the IFN-..gamma..-treated group following 2-3 days of culture. Supplementing the growth medium with additional L-tryptophan reversed the antiproliferative effect of IFN-..gamma.. against KB cells in a dose- and time-dependent manner. The antiproliferative effects of IFN-..cap alpha.. and IFN-..gamma.. on SW480 and NCI-H128 cells, which are independent of the dioxygenase activity, and the inability of added L-tryptophan to reverse the effects of IFN-..gamma.. in WiDr cells suggest multiple mechanisms of action of the IFNs. The data show that the antiproliferative effect of IFN-..gamma.. through induction of indoleamine 2,3-dioxygenase, with a consequent L-tryptophan deprivation, is an effective means of regulating cell growth.

  2. HCV core protein induces hepatic lipid accumulation by activating SREBP1 and PPAR{gamma}

    SciTech Connect

    Kim, Kook Hwan; Hong, Sung Pyo; Kim, KyeongJin; Park, Min Jung; Kim, Kwang Jin; Cheong, JaeHun . E-mail: molecule85@pusan.ac.kr

    2007-04-20

    Hepatic steatosis is a common feature in patients with chronic hepatitis C virus (HCV) infection. HCV core protein plays an important role in the development of hepatic steatosis in HCV infection. Because SREBP1 (sterol regulatory element binding protein 1) and PPAR{gamma} (peroxisome proliferators-activated receptor {gamma}) are involved in the regulation of lipid metabolism of hepatocyte, we sought to determine whether HCV core protein may impair the expression and activity of SREBP1 and PPAR{gamma}. In this study, it was demonstrated that HCV core protein increases the gene expression of SREBP1 not only in Chang liver, Huh7, and HepG2 cells transiently transfected with HCV core protein expression plasmid, but also in Chang liver-core stable cells. Furthermore, HCV core protein enhanced the transcriptional activity of SREBP1. In addition, HCV core protein elevated PPAR{gamma} transcriptional activity. However, HCV core protein had no effect on PPAR{gamma} gene expression. Finally, we showed that HCV core protein stimulates the genes expression of lipogenic enzyme and fatty acid uptake associated protein. Therefore, our finding provides a new insight into the mechanism of hepatic steatosis by HCV infection.

  3. A peroxisome proliferator-activated receptor-gamma agonist and other constituents from Chromolaena odorata.

    PubMed

    Dat, Nguyen Tien; Lee, Kyeong; Hong, Young-Soo; Kim, Young Ho; Minh, Chau Van; Lee, Jung Joon

    2009-06-01

    Peroxisome proliferator-activated receptors (PPARs) are key regulators of lipid and glucose metabolism and have become important therapeutic targets for various diseases. The phytochemical investigation of the chloroform-soluble extract of Chromolaena odorata led to the isolation of a PPAR-gamma agonist, (9 S,13 R)-12-oxo-phytodienoic acid (1), together with 12 other compounds. The structures of chromomoric acid G (2), a new dehydrogenated derivative of 1, and chromolanone (3) were elucidated based on spectroscopic methods. Compound 1 showed a significant effect on PPAR-gamma activation in comparison with rosiglitazone. However, compound 2 was inactive, suggesting that the dehydrogenation of the prostaglandin-like structure in 1 abrogates its PPAR-gamma agonistic activity. PMID:19242902

  4. Gamma radiation effects on phenolics, antioxidants activity and in vitro digestion of pistachio ( Pistachia vera) hull

    NASA Astrophysics Data System (ADS)

    Behgar, M.; Ghasemi, S.; Naserian, A.; Borzoie, A.; Fatollahi, H.

    2011-09-01

    The effect of gamma radiation (10, 20, 30, 40, 50 and 60 kGy) on tannin, total phenolics, antioxidants activity and in vitro digestion of pistachio hulls has been investigated in this study. The possibility of using the radial diffusion method based on software measurement of the rings area has also been investigated in this study. The software based method in radial diffusion method showed a higher r2 (0.995) value when compared to the traditional method. Irradiation reduced the tannin content ( P<0.01) and activity of antioxidants ( P<0.05) of pistachio hull extracts but increased the total phenolic content ( P<0.05). There was no effect of gamma irradiation on the in vitro digestion of the pistachio hull. Irradiation decreased the digestion rate of the pistachio hull at the dose of 40 kGy when compared to the control. This study showed that gamma irradiation decreased tannin and antioxidants activity of pistachio hull.

  5. Testing of regolith of celestial bolides with active neutron gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Vostrukhin, Andrey; Mitrofanov, Igor; Golovin, Dmitry; Litvak, Maxim; Sanin, Anton

    2015-04-01

    Current space instruments for studying planet's surface include gamma ray spectrometers that detect natural radioactive isotopes as well as gamma-rays induced in subsurface by galactic cosmic rays. When measuring from celestial body's surface, statistics and amount of detected elements can be dramatically increased with active methods, where soil exposed to artificial flux of particles. One good example is the Russian Dynamic Albedo of Neutron (DAN) instrument onboard Martian Science Laboratory mission (Curiosity rover) developed in 2005-2011. It is the first active neutron spectrometer flown to another planet as part of a landed mission to investigate subsurface water distribution and which has now successfully operated for more than two years on the Martian surface. Presentation describes a number of space instruments for different landers and rovers being developed in Russian Space Research Institute for studying Moon and Mars, as well as method of active neutron and gamma spectrometry overview.

  6. Results of mobile gamma scanning activities in St. Louis, Missouri

    SciTech Connect

    Rodriguez, R E; Witt, D A; Cottrell, W D; Carrier, R F

    1991-06-01

    From 1942 through approximately 1966, the Mallinckrodt Chemical Works operated four plants in St. Louis, Missouri, for the Manhattan Engineer District and the Atomic Energy Commission. A variety of production processes using uranium- and radium-bearing ore materials were performed at the plants. It is the policy of the DOE to verify that radiological conditions at such sites or facilities comply with current DOE guidelines. Guidelines for release and use of such sites have become more stringent as research has provided more information since previous cleanups. The Formerly Utilized Sites Remedial Action Program (FUSRAP) was established as part of that effort to confirm the closeout status of facilities under contract to agencies preceding DOE during early nuclear energy development. Under the FUSRAP program, the Mallinckrodt properties have been previously investigated to determine the extent of on-site radiological contamination. At the request of DOE, Oak Ridge National Laboratory (ORNL) conducted a survey in May 1990, of public roadways and suspected haul routes between the Mallinckrodt plant and storage sites in St. Louis to ensure that no residual radioactive materials were conveyed off-site. A mobile gamma scanning van with an on-board computer system was used to identify possible anomalies. Suspect areas are those displaying measurements deviating from gamma exposure rates identified as typical for radiologically unenhanced areas in the vicinity of the areas of interest. The instrumentation highlighted three anomaly locations each of which measured less than 1m{sup 2} in size. None of the slightly elevated radiation levels originated from material associated with former AEC-related processing operations in the area. The anomalies resulted from elevated concentrations of radionuclides present in phosphate fertilizers, increased thorium in road-base gravel, and emanations from the radioactive storage site near the Latty Avenue airport. 9 refs., 3 figs.

  7. The Differential Interactions of Peroxisome Proliferator-Activated Receptor [gamma] Ligands with Tyr473 Is a Physical Basis for Their Unique Biological Activities

    SciTech Connect

    Einstein, Monica; Akiyama, Taro E.; Castriota, Gino A.; Wang, Chuanlin F.; McKeever, Brian; Mosley, Ralph T.; Becker, Joseph W.; Moller, David E.; Meinke, Peter T.; Wood, Harold B.; Berger, Joel P.

    2008-08-01

    Despite their proven antidiabetic efficacy, widespread use of peroxisome proliferator-activated receptor (PPAR){gamma} agonists has been limited by adverse cardiovascular effects. To overcome this shortcoming, selective PPAR{gamma} modulators (SPPAR{gamma}Ms) have been identified that have antidiabetic efficacy comparable with full agonists with improved tolerability in preclinical species. The results of structural studies support the proposition that SPPAR{gamma}Ms interact with PPAR{gamma} differently from full agonists, thereby providing a physical basis for their novel activities. Herein, we describe a novel PPAR{gamma} ligand, SPPAR{gamma}M2. This compound was a partial agonist in a cell-based transcriptional activity assay, with diminished adipogenic activity and an attenuated gene signature in cultured human adipocytes. X-ray cocrystallography studies demonstrated that, unlike rosiglitazone, SPPAR{gamma}M2 did not interact with the Tyr473 residue located within helix 12 of the ligand binding domain (LBD). Instead, SPPAR{gamma}M2 was found to bind to and activate human PPAR{gamma} in which the Tyr473 residue had been mutated to alanine (hPPAR{gamma}Y473A), with potencies similar to those observed with the wild-type receptor (hPPAR{gamma}WT). In additional studies, we found that the intrinsic binding and functional potencies of structurally distinct SPPAR{gamma}Ms were not diminished by the Y473A mutation, whereas those of various thiazolidinedione (TZD) and non-TZD PPAR{gamma} full agonists were reduced in a correlative manner. These results directly demonstrate the important role of Tyr473 in mediating the interaction of full agonists but not SPPAR{gamma}Ms with the PPAR{gamma} LBD, thereby providing a precise molecular determinant for their differing pharmacologies.

  8. Gamma-glutamyltransferase activity in mammary gland of pregnant rats and its regulation by ovarian hormones, prolactin and placental lactogen.

    PubMed Central

    Bussmann, L E; Deis, R P

    1984-01-01

    Ovariectomy and ovariectomy plus hysterectomy on day 18 of pregnancy increased gamma-glutamyltransferase activity in the mammary gland. The withdrawal of progesterone and the subsequent release of prolactin are responsible for the rise in enzyme activity. Rat placental lactogen in the absence of prolactin and progesterone is able to induce gamma-glutamyltransferase activity. PMID:6149746

  9. Utilization of recycled neutron source to teach prompt gamma analysis activation-PGNA

    NASA Astrophysics Data System (ADS)

    Delgado-Correal, Camilo; Munera, Hector

    2008-03-01

    Neutron activation analysis based on prompt gamma ray emission has significantly developed during the past twenty years. The technique is particularly suited for the identification of low atomic number elements, as nitrogen that is a main component of drugs and explosives. Identification of these substances is important in the context of humanitarian demining, and in the control of illicit traffic of drugs and explosives. As a good example of recycling of radioactive sources, a ^241Am-Be neutron source emitting 10^7neutron/s, that was not longer in use for other purposes at Ingeominas, was used to build a neutron irradiator that can be used to teach prompt gamma ray analysis, and other nuclear techniques. We irradiated individual samples, each about 4 gram, of three different elements: nitrogen in urea, silicon in milled rock, and cadmium in cadmium oxide. The prompt gamma rays emitted in the nuclear reactions ^112Cd (neutron,gamma) ^113Cd, ^28Si (neutron,gamma) ^29Si and ^14N (neutron,gamma) ^15N were identified using a well-type NaI (Tl) detector, connected to a multi-channel analyzer.

  10. Carbonic anhydrase III regulates peroxisome proliferator-activated receptor-{gamma}2

    SciTech Connect

    Mitterberger, Maria C.; Kim, Geumsoo; Rostek, Ursula; Levine, Rodney L.; Zwerschke, Werner

    2012-05-01

    Carbonic anhydrase III (CAIII) is an isoenzyme of the CA family. Because of its low specific anhydrase activity, physiological functions in addition to hydrating CO{sub 2} have been proposed. CAIII expression is highly induced in adipogenesis and CAIII is the most abundant protein in adipose tissues. The function of CAIII in both preadipocytes and adipocytes is however unknown. In the present study we demonstrate that adipogenesis is greatly increased in mouse embryonic fibroblasts (MEFs) from CAIII knockout (KO) mice, as demonstrated by a greater than 10-fold increase in the induction of fatty acid-binding protein-4 (FABP4) and increased triglyceride formation in CAIII{sup -/-} MEFs compared with CAIII{sup +/+} cells. To address the underlying mechanism, we investigated the expression of the two adipogenic key regulators, peroxisome proliferator-activated receptor-{gamma}2 (PPAR{gamma}2) and CCAAT/enhancer binding protein-{alpha}. We found a considerable (approximately 1000-fold) increase in the PPAR{gamma}2 expression in the CAIII{sup -/-} MEFs. Furthermore, RNAi-mediated knockdown of endogenous CAIII in NIH 3T3-L1 preadipocytes resulted in a significant increase in the induction of PPAR{gamma}2 and FABP4. When both CAIII and PPAR{gamma}2 were knocked down, FABP4 was not induced. We conclude that down-regulation of CAIII in preadipocytes enhances adipogenesis and that CAIII is a regulator of adipogenic differentiation which acts at the level of PPAR{gamma}2 gene expression. -- Highlights: Black-Right-Pointing-Pointer We discover a novel function of Carbonic anhydrase III (CAIII). Black-Right-Pointing-Pointer We show that CAIII is a regulator of adipogenesis. Black-Right-Pointing-Pointer We demonstrate that CAIII acts at the level of PPAR{gamma}2 gene expression. Black-Right-Pointing-Pointer Our data contribute to a better understanding of the role of CAIII in fat tissue.

  11. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L.

    NASA Astrophysics Data System (ADS)

    Tahir, D.; Halide, H.; Wahab, A. W.; Kurniawan, D.

    2014-09-01

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  12. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L

    SciTech Connect

    Tahir, D. Halide, H. Kurniawan, D.; Wahab, A. W.

    2014-09-25

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  13. Two cis-DNA elements involved in myeloid-cell-specific expression and gamma interferon (IFN-gamma) activation of the human high-affinity Fc gamma receptor gene: a novel IFN regulatory mechanism.

    PubMed Central

    Perez, C; Wietzerbin, J; Benech, P D

    1993-01-01

    The human high-affinity receptor for the constant region of immunoglobulin G (human Fc gamma R1) is encoded by two mRNAs induced selectively by gamma interferon (IFN-gamma) and expressed in cells of myeloid lineage. The cis-DNA element (GRR) previously found to confer IFN-gamma responsiveness to this gene acts as an inducible enhancer and is the target of an IFN-gamma-activated factor(s) (GIRE-BP) in cells of different origins. Although the GRR motif is not related to the DNA elements involved in the regulation of other IFN-stimulated genes, GIRE-BP binding depends on the IFN-gamma-dependent activation of the 91-kDa protein known to be one of the factors of a transcriptional complex activated by IFN-alpha. Deletions of the Fc gamma R1 promoter allowed us to identify a 25-bp element, downstream from the GRR motif, conferring cell-type-specific expression. This element, called MATE (myeloid activating transcription element), is the DNA target for constitutive factors forming two complexes, MATE-BP1 and MATE-BP2. In accordance with the functional analysis, MATE-BP binding activities were detected in extracts prepared from myeloid cell lines such as THP-1, HL-60, and U-937 but not in HeLa cell extracts. The MATE motif is present not only in the promoter of other Fc receptor genes but also in several promoters of genes whose expression is restricted to monocytic cells. Our results suggest that human Fc gamma R1 gene expression in myeloid cells is initiated by the interaction of IFN-gamma-activated factors with cell-type-specific factors through their binding to the GRR and MATE motifs. Images PMID:8455606

  14. Effect of gamma irradiation on the physiological activity of Korean soybean fermented foods, Chungkookjang and Doenjang

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Son, Jun-Ho; Yook, Hong-Sun; Jo, Cheorun; Kim, Dong-Ho

    2002-06-01

    Effects of gamma irradiation on the physiological activity of Korean soybean fermented foods were investigated. Chungkookjang, the whole cooked soybean product and Doenjang, soybean paste were purchased and irradiated at 5, 10 and 20 kGy of absorbed doses. The physiological activity was evaluated by angiotensin converting enzyme inhibition, xanthine oxidase inhibition, tyrosinase inhibition and radical scavenging ability and results indicated that at 10 kGy or below did not show any significant change on physiological activities by irradiation.

  15. Activation of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) induces cell death through MAPK-dependent mechanism in osteoblastic cells

    SciTech Connect

    Kim, Sung Hun; Yoo, Chong Il; Kim, Hui Taek; Park, Ji Yeon; Kwon, Chae Hwa; Keun Kim, Yong . E-mail: kim430@pusan.ac.kr

    2006-09-01

    The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPAR{gamma} agonists in osteoblastic cells. Ciglitazone and troglitazone, PPAR{gamma} agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPAR{alpha} agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPAR{gamma} antagonist GW9662. Ciglitazone treatment caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis.

  16. Synthesis of theanine from glutamic acid gamma-methyl ester and ethylamine catalyzed by Escherichia coli having gamma-glutamyltranspeptidase activity.

    PubMed

    Zhang, Fei; Zheng, Qing-Zhong; Jiao, Qing-Cai; Liu, Jun-Zhong; Zhao, Gen-Hai

    2010-08-01

    Glutamic acid gamma-methyl ester (GAME) was used as substrate for theanine synthesis catalyzed by Escherichia coli cells possessing gamma-glutamyltranspeptidase activity. The yield was about 1.2-fold higher than with glutamine as substrate. The reaction was optimal at pH 10 and 45 degrees C, and the optimal substrate ratio of GAME to ethylamine was 1:10 (mol/mol). With GAME at 100 mmol, 95 mmol theanine was obtained after 8 h. PMID:20383735

  17. Results of mobile gamma scanning activities in Tonawanda, New York

    SciTech Connect

    Cottrell, W.D.; Witt, D.A.; Rodriguez, R.E.; Carrier, R.F.

    1990-12-01

    During the 1940s, the Linde Air Products Division of Union Carbide operated a plant in Tonawanda, New York, for the Manhattan Engineer District (MED) and the Atomic Energy Commission (AEC). Uranium production and some nickel processing were conducted at the site. It is the policy of the US Department of Energy (DOE) to verify that radiological conditions at such sites or facilities comply with current DOE guidelines. Guidelines for release and use of such sites have become more stringent as research has provided more information since previous cleanups. The Formerly Utilized Sites Remedial Action Program (FUSRAP) was established as part of that effort to confirm the closeout status of facilities under contract to agencies preceding DOE during early nuclear energy development. Under the FUSRAP program, the Linde site itself has been previously investigated to determine the extent of on-site radiological contamination. As a precaution to insure that no residual radioactive materials were transported off-site, the Department of Energy requested that ORNL survey the area in the vicinity of the Linde Plant, the waste water treatment facility on Tower Road, the Sheridan Park Fire Station (District 4), and the Tonawanda Landfill to assess whether any residual radioactive material could be detected. The survey was conducted the week of April 3, 1990. Results of analysis of soil samples from the Tonawanda Landfill revealed slightly elevated concentrations of {sup 238}U and {sup 226}Ra suggestive of residuals from former Linde Plant operations. Therefore, it is recommended that additional surveying of the landfill property and of Sheridan Creek from south of the Linde property to its confluence with the Niagara River be conducted. The survey should include the measurement of gamma radiation levels and radionuclide analysis of silt samples. 6 refs., 4 figs., 1 tab.

  18. Pedunculopontine Nucleus Gamma Band Activity-Preconscious Awareness, Waking, and REM Sleep.

    PubMed

    Urbano, Francisco J; D'Onofrio, Stasia M; Luster, Brennon R; Beck, Paige B; Hyde, James Robert; Bisagno, Veronica; Garcia-Rill, Edgar

    2014-01-01

    The pedunculopontine nucleus (PPN) is a major component of the reticular activating system (RAS) that regulates waking and REM sleep, states of high-frequency EEG activity. Recently, we described the presence of high threshold, voltage-dependent N- and P/Q-type calcium channels in RAS nuclei that subserve gamma band oscillations in the mesopontine PPN, intralaminar parafascicular nucleus (Pf), and pontine subcoeruleus nucleus dorsalis (SubCD). Cortical gamma band activity participates in sensory perception, problem solving, and memory. Rather than participating in the temporal binding of sensory events as in the cortex, gamma band activity in the RAS may participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our actions. That is, the RAS may play an early permissive role in volition. Our latest results suggest that (1) the manifestation of gamma band activity during waking may employ a separate intracellular pathway compared to that during REM sleep, (2) neuronal calcium sensor (NCS-1) protein, which is over expressed in schizophrenia and bipolar disorder, modulates gamma band oscillations in the PPN in a concentration-dependent manner, (3) leptin, which undergoes resistance in obesity resulting in sleep dysregulation, decreases sodium currents in PPN neurons, accounting for its normal attenuation of waking, and (4) following our discovery of electrical coupling in the RAS, we hypothesize that there are cell clusters within the PPN that may act in concert. These results provide novel information on the mechanisms controlling high-frequency activity related to waking and REM sleep by elements of the RAS. PMID:25368599

  19. Pedunculopontine Nucleus Gamma Band Activity-Preconscious Awareness, Waking, and REM Sleep

    PubMed Central

    Urbano, Francisco J.; D’Onofrio, Stasia M.; Luster, Brennon R.; Beck, Paige B.; Hyde, James Robert; Bisagno, Veronica; Garcia-Rill, Edgar

    2014-01-01

    The pedunculopontine nucleus (PPN) is a major component of the reticular activating system (RAS) that regulates waking and REM sleep, states of high-frequency EEG activity. Recently, we described the presence of high threshold, voltage-dependent N- and P/Q-type calcium channels in RAS nuclei that subserve gamma band oscillations in the mesopontine PPN, intralaminar parafascicular nucleus (Pf), and pontine subcoeruleus nucleus dorsalis (SubCD). Cortical gamma band activity participates in sensory perception, problem solving, and memory. Rather than participating in the temporal binding of sensory events as in the cortex, gamma band activity in the RAS may participate in the processes of preconscious awareness, and provide the essential stream of information for the formulation of many of our actions. That is, the RAS may play an early permissive role in volition. Our latest results suggest that (1) the manifestation of gamma band activity during waking may employ a separate intracellular pathway compared to that during REM sleep, (2) neuronal calcium sensor (NCS-1) protein, which is over expressed in schizophrenia and bipolar disorder, modulates gamma band oscillations in the PPN in a concentration-dependent manner, (3) leptin, which undergoes resistance in obesity resulting in sleep dysregulation, decreases sodium currents in PPN neurons, accounting for its normal attenuation of waking, and (4) following our discovery of electrical coupling in the RAS, we hypothesize that there are cell clusters within the PPN that may act in concert. These results provide novel information on the mechanisms controlling high-frequency activity related to waking and REM sleep by elements of the RAS. PMID:25368599

  20. Measuring the activity of a 51Cr neutrino source based on the gamma-radiation spectrum

    NASA Astrophysics Data System (ADS)

    Gorbachev, V. V.; Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-01

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of 51Cr is presented.

  1. AGILE confirmation of enhanced gamma-ray activity from the Blazar 1ES 1959+650

    NASA Astrophysics Data System (ADS)

    Lucarelli, F.; Pittori, C.; Verrecchia, F.; Bulgarelli, A.; Fioretti, V.; Zoli, A.; Piano, G.; Munar-Adrover, P.; Tavani, M.; Donnarumma, I.; Vercellone, S.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-06-01

    Following ATel #9148, reporting multi-wavelength activity from the BL Lac type blazar 1ES 1959+650, AGILE also detects increased gamma-ray emission above 100 MeV from a position compatible with this BL Lac source.

  2. Chemical synthesis of nucleoside-gamma-[32P]triphosphates of high specific activity.

    PubMed

    Janecka, A; Panusz, H; Pankowski, J; Koziołkiewicz, W

    1980-01-01

    A simple chemical procedure for the preparation of four common ribonucleoside 5-gamma-[32P]triphosphates of high specific activity (up to 10 Ci/mmole) based on the condensation of orthophosphoric acid with the corresponding nucleoside 5-diphosphate in the presence of ethyl chloroformate as well as the methods of purification and identification of the products are described. PMID:7375446

  3. Stability evaluation and correction of a pulsed neutron generator prompt gamma activation analysis system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Source output stability is important for accurate measurement in prompt gamma neutron activation. This is especially true when measuring low-concentration elements such as in vivo nitrogen (~2.5% of body weight). We evaluated the stability of the compact DT neutron generator within an in vivo nitrog...

  4. Chemical composition and lipoxygenase activity in soybeans (Glycine max L. Merr.) submitted to gamma irradiation

    NASA Astrophysics Data System (ADS)

    Barros, Érica Amanda de; Broetto, Fernando; Bressan, Dayanne F.; Sartori, Maria M. P.; Costa, Vladimir E.

    2014-05-01

    Soybeans are an important food due to their functional and nutritional characteristics. However, consumption by western populations is limited by the astringent taste of soybeans and their derivatives which results from the action of lipoxygenase, an enzyme activated during product processing. The aim of this study was to evaluate the effect of gamma irradiation on the chemical composition and specific activity of lipoxygenase in different soybean cultivars. Soybeans were stored in plastic bags and irradiated with doses of 2.5, 5 and 10 kGy. The chemical composition (moisture, protein, lipids, ashes, crude fiber, and carbohydrates) and lipoxygenase specific activity were determined for each sample. Gamma irradiation induced a small increase of protein and lipid content in some soybean cultivars, which did not exceed the highest content of 5% and 26%, respectively, when compared to control. Lipoxygenase specific activity decreased in the three cultivars with increasing gamma irradiation dose. In conclusion, the gamma irradiation doses used are suitable to inactivate part of lipoxygenase while not causing expressive changes in the chemical composition of the cultivars studied.

  5. Vitamin E, glutathione S-transferase and gamma-glutamyl transpeptidase activities in cultured hepatocytes of rats treated with carcinogens.

    PubMed

    Ong, F B; Wan Ngah, W Z; Top, A G; Khalid, B A; Shamaan, N A

    1994-03-01

    1. The effects of alpha-tocopherol and gamma-tocotrienol on glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (gamma-GT) activities in cultured hepatocytes prepared from rats treated with diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) were investigated. 2. Both the alpha-tocopherol and gamma-tocotrienol treated hepatocytes showed significantly higher (P < 0.05) GST activities than untreated hepatocytes prepared from the carcinogen treated rats in the first 3 days of culture. Treatment with alpha-tocopherol and gamma-tocotrienol generally resulted in a tendency to increase the GST activities above that in the untreated hepatocytes. 3. Treatment with high doses (125-250 microM) of alpha-tocopherol and low doses (12.5-25 microM) of gamma-tocotrienol generally resulted in a significant reduction in gamma-GT activities at 1-3 days. gamma-GT activities are reduced as the dose of alpha-tocopherol and gamma-tocotrienol are increased. PMID:7910569

  6. 1,25 dihydroxyvitamin D3 stimulates phospholipase C-gamma in rat colonocytes: role of c-Src in PLC-gamma activation.

    PubMed Central

    Khare, S; Bolt, M J; Wali, R K; Skarosi, S F; Roy, H K; Niedziela, S; Scaglione-Sewell, B; Aquino, B; Abraham, C; Sitrin, M D; Brasitus, T A; Bissonnette, M

    1997-01-01

    Our laboratory has previously demonstrated that 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) rapidly stimulated polyphosphoinositide (PI) hydrolysis, raised intracellular Ca2+, and activated two Ca2+-dependent protein kinase C (PKC) isoforms, PKC-alpha and -betaII in the rat large intestine. We also showed that the direct addition of 1,25(OH)2D3 to isolated colonic membranes failed to stimulate PI hydrolysis, but required secosteroid treatment of intact colonocytes, suggesting the involvement of a soluble factor. Furthermore, this PI hydrolysis was restricted to the basal lateral plasma membrane of these cells. In the present studies, therefore, we examined whether polyphosphoinositide-phospholipase C-gamma (PI-PLC-gamma), a predominantly cytosolic isoform of PI-PLC, was involved in the hydrolysis of colonic membrane PI by 1,25(OH)2D3. This isoform has been shown to be activated and membrane-associated by tyrosine phosphorylation. We found that 1,25(OH)2D3 caused a significant increase in the biochemical activity, particulate association, and the tyrosine phosphorylation of PLC-gamma, specifically in the basal lateral membranes. This secosteroid also induced a twofold increase in the activity of Src, a proximate activator of PLC-gamma in other cells, with peaks at 1 and 9 min in association with Src tyrosine dephosphorylation. 1,25(OH)2D3 also increased the physical association of activated c-Src with PLC-gamma. In addition, Src isolated from colonocytes treated with 1,25(OH)2D3, demonstrated an increased ability to phosphorylate exogenous PLC-gamma in vitro. Inhibition of 1,25(OH)2D3-induced Src activation by PP1, a specific Src family protein tyrosine kinase inhibitor, blocked the ability of this secosteroid to stimulate the translocation and tyrosine phosphorylation of PLC-gamma in the basolateral membrane (BLM). Src activation was lost in D deficiency, and was reversibly restored with the in vivo repletion of 1,25(OH)2D3. These studies demonstrate for the first time

  7. Spatial and temporal relationships of electrocorticographic alpha and gamma activity during auditory processing.

    PubMed

    Potes, Cristhian; Brunner, Peter; Gunduz, Aysegul; Knight, Robert T; Schalk, Gerwin

    2014-08-15

    Neuroimaging approaches have implicated multiple brain sites in musical perception, including the posterior part of the superior temporal gyrus and adjacent perisylvian areas. However, the detailed spatial and temporal relationship of neural signals that support auditory processing is largely unknown. In this study, we applied a novel inter-subject analysis approach to electrophysiological signals recorded from the surface of the brain (electrocorticography (ECoG)) in ten human subjects. This approach allowed us to reliably identify those ECoG features that were related to the processing of a complex auditory stimulus (i.e., continuous piece of music) and to investigate their spatial, temporal, and causal relationships. Our results identified stimulus-related modulations in the alpha (8-12 Hz) and high gamma (70-110 Hz) bands at neuroanatomical locations implicated in auditory processing. Specifically, we identified stimulus-related ECoG modulations in the alpha band in areas adjacent to primary auditory cortex, which are known to receive afferent auditory projections from the thalamus (80 of a total of 15,107 tested sites). In contrast, we identified stimulus-related ECoG modulations in the high gamma band not only in areas close to primary auditory cortex but also in other perisylvian areas known to be involved in higher-order auditory processing, and in superior premotor cortex (412/15,107 sites). Across all implicated areas, modulations in the high gamma band preceded those in the alpha band by 280 ms, and activity in the high gamma band causally predicted alpha activity, but not vice versa (Granger causality, p<1e(-8)). Additionally, detailed analyses using Granger causality identified causal relationships of high gamma activity between distinct locations in early auditory pathways within superior temporal gyrus (STG) and posterior STG, between posterior STG and inferior frontal cortex, and between STG and premotor cortex. Evidence suggests that these

  8. The WISE Gamma-Ray Strip Parameterization: The Nature of the Gamma-Ray Active Galactic Nuclei of Uncertain Type

    NASA Astrophysics Data System (ADS)

    Massaro, F.; D'Abrusco, R.; Tosti, G.; Ajello, M.; Gasparrini, D.; Grindlay, J. E.; Smith, Howard A.

    2012-05-01

    Despite the large number of discoveries made recently by Fermi, the origins of the so-called unidentified γ-ray sources remain unknown. The large number of these sources suggests that there could be a population among them that significantly contributes to the isotropic gamma-ray background and it is therefore crucial to understand their nature. The first step toward a complete comprehension of the unidentified γ-ray source population is to identify those that can be associated with blazars, the most numerous class of extragalactic sources in the γ-ray sky. Recently, we discovered that blazars can be recognized and separated from other extragalactic sources using the infrared (IR) WISE satellite colors. The blazar population delineates a remarkable and distinctive region of the IR color-color space, the WISE blazar strip. In particular, the subregion delineated by the γ-ray emitting blazars is even narrower and we named it the WISE Gamma-ray Strip (WGS). In this paper, we parameterize the WGS on the basis of a single parameter s that we then use to determine if γ-ray active galactic nuclei of the uncertain type (AGUs) detected by Fermi are consistent with the WGS and can be considered blazar candidates. We find that 54 AGUs out of a set of 60 analyzed have IR colors consistent with the WGS; only 6 AGUs are outliers. This result implies that a very high percentage (i.e., in this sample about 90%) of the AGUs detected by Fermi are indeed blazar candidates.

  9. Active Neutron and Gamma-Ray Instrumentation for In Situ Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, A.; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    We describe the development of an instrument capable of detailed in situ bulk geochemical analysis of the surface of planets, moons, asteroids, and comets. This instrument technology uses a pulsed neutron generator to excite the solid materials of a planet and measures the resulting neutron and gamma-ray emission with its detector system. These time-resolved neutron and gamma-ray data provide detailed information about the bulk elemental composition, chemical context, and density distribution of the soil within 50 cm of the surface. While active neutron scattering and neutron-induced gamma-ray techniques have been used extensively for terrestrial nuclear well logging applications, our goal is to apply these techniques to surface instruments for use on any solid solar system body. As described, experiments at NASA Goddard Space Flight Center use a prototype neutron-induced gamma-ray instrument and the resulting data presented show the promise of this technique for becoming a versatile, robust, workhorse technology for planetary science, and exploration of any of the solid bodies in the solar system. The detection of neutrons at the surface also provides useful information about the material. This paper focuses on the data provided by the gamma-ray detector.

  10. THE REMARKABLE {gamma}-RAY ACTIVITY IN THE GRAVITATIONALLY LENSED BLAZAR PKS 1830-211

    SciTech Connect

    Donnarumma, I.; De Rosa, A.; Vittorini, V.; Tavani, M.; Striani, E.; Pacciani, L.; Popovic, L. C.; Simic, S.; Kuulkers, E.; Vercellone, S.; Verrecchia, F.; Pittori, C.; Giommi, P.; Barbiellini, G.; Bulgarelli, A.

    2011-08-01

    We report the extraordinary {gamma}-ray activity (E > 100 MeV) of the gravitationally lensed blazar PKS 1830-211 (z = 2.507) detected by AGILE between 2010 October and November. On October 14, the source experienced a factor of {approx}12 flux increase with respect to its average value and remained brightest at this flux level ({approx}500 x 10{sup -8} photons cm{sup -2} s{sup -1}) for about four days. The one-month {gamma}-ray light curve across the flare showed a mean flux F(E > 100 MeV) = 200 x 10{sup -8} photons cm{sup -2} s{sup -1}, which resulted in a factor of four enhancement with respect to the average value. Following the {gamma}-ray flare, the source was observed in near-IR (NIR)-optical energy bands at the Cerro Tololo Inter-American Observatory and in X-Rays by Swift/X-Ray Telescope and INTEGRAL/IBIS. The main result of these multifrequency observations is that the large variability observed in {gamma}-rays does not have a significant counterpart at lower frequencies: no variation greater than a factor of {approx}1.5 appeared in the NIR and X-Ray energy bands. PKS 1830-211 is then a good '{gamma}-ray only flaring' blazar showing substantial variability only above 10-100 MeV. We discuss the theoretical implications of our findings.

  11. Stimulus-induced and state-dependent sustained gamma activity is tightly coupled to the hemodynamic response in humans.

    PubMed

    Koch, Stefan P; Werner, Peter; Steinbrink, Jens; Fries, Pascal; Obrig, Hellmuth

    2009-11-01

    A prompt behavioral response to a stimulus depends both on the salience of the stimulus as well as the subject's preparedness. Thus, both stimulus properties and cognitive factors, such as attention, may determine the strength of neuronal synchronization in the gamma range. For a comprehensive investigation of stimulus-response processing through noninvasive imaging, it is, however, a crucial issue whether both kinds of gamma modulation elicit a hemodynamic response. Here, we show that, in the human visual cortex, stimulus strength and internal state modulate sustained gamma activity and hemodynamic response in close correspondence. When participants reported velocity changes of gratings varying in contrast, gamma activity (35-70 Hz) increased systematically with contrast. For stimuli of constant contrast, the amplitude of gamma activity before the behaviorally relevant velocity change was inversely correlated to the behavioral response latency. This indicates that gamma activity also reflects an overall attentive state. For both sources of variance, gamma activity was tightly coupled to the hemodynamic response measured through optical topography. Because of the close relationship between high-frequency neuronal activity and the hemodynamic signal, we conclude that both stimulus-induced and state-dependent gamma activity trigger a metabolic demand and are amenable to vascular-based imaging. PMID:19890006

  12. Antioxidant activities of fucoidan degraded by gamma irradiation and acidic hydrolysis

    NASA Astrophysics Data System (ADS)

    Lim, Sangyong; Choi, Jong-il; Park, Hyun

    2015-04-01

    Low molecular weight fucoidan, prepared by radical degradation using gamma ray was investigated for its antioxidant activities with different assay methods. As the molecular weight of fucoidan decreased with a higher absorbed dose, ferric-reducing antioxidant power values increased, but β-carotene bleaching inhibition did not change significantly. The antioxidant activity of acid-degraded fucoidan was also examined to investigate the effect of different degradation methods. At the same molecular weight, fucoidan degraded by gamma irradiation showed higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity than that observed with the acidic method. This result reveals that in addition to molecular weight, the degradation method affects the antioxidant activity of fucoidan.

  13. Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks?

    PubMed Central

    Martin, Claire; Ravel, Nadine

    2014-01-01

    Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to “bind” distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15–40 Hz) and gamma (60–100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory. PMID:25002840

  14. To Perceive or Not Perceive: The Role of Gamma-band Activity in Signaling Object Percepts

    PubMed Central

    Castelhano, João; Rebola, José; Leitão, Bruno; Rodriguez, Eugenio; Castelo-Branco, Miguel

    2013-01-01

    The relation of gamma-band synchrony to holistic perception in which concerns the effects of sensory processing, high level perceptual gestalt formation, motor planning and response is still controversial. To provide a more direct link to emergent perceptual states we have used holistic EEG/ERP paradigms where the moment of perceptual “discovery” of a global pattern was variable. Using a rapid visual presentation of short-lived Mooney objects we found an increase of gamma-band activity locked to perceptual events. Additional experiments using dynamic Mooney stimuli showed that gamma activity increases well before the report of an emergent holistic percept. To confirm these findings in a data driven manner we have further used a support vector machine classification approach to distinguish between perceptual vs. non perceptual states, based on time-frequency features. Sensitivity, specificity and accuracy were all above 95%. Modulations in the 30–75 Hz range were larger for perception states. Interestingly, phase synchrony was larger for perception states for high frequency bands. By focusing on global gestalt mechanisms instead of local processing we conclude that gamma-band activity and synchrony provide a signature of holistic perceptual states of variable onset, which are separable from sensory and motor processing. PMID:23785494

  15. Gamma band activity and the P3 reflect post-perceptual processes, not visual awareness

    PubMed Central

    Pitts, Michael A.; Padwal, Jennifer; Fennelly, Daniel; Martínez, Antígona; Hillyard, Steven A.

    2014-01-01

    A primary goal in cognitive neuroscience is to identify neural correlates of conscious perception (NCC). By contrasting conditions in which subjects are aware versus unaware of identical visual stimuli, a number of candidate NCCs have emerged, among them induced gamma band activity in the EEG and the P3 event-related potential. In most previous studies, however, the critical stimuli were always directly relevant to the subjects’ task, such that aware versus unaware contrasts may well have included differences in post-perceptual processing in addition to differences in conscious perception per se. Here, in a series of EEG experiments, visual awareness and task relevance were manipulated independently. Induced gamma activity and the P3 were absent for task-irrelevant stimuli regardless of whether subjects were aware of such stimuli. For task-relevant stimuli, gamma and the P3 were robust and dissociable, indicating that each reflects distinct post-perceptual processes necessary for carrying-out the task but not for consciously perceiving the stimuli. Overall, this pattern of results challenges a number of previous proposals linking gamma band activity and the P3 to conscious perception. PMID:25063731

  16. Gamma Activity Coupled to Alpha Phase as a Mechanism for Top-Down Controlled Gating

    PubMed Central

    Bonnefond, Mathilde; Jensen, Ole

    2015-01-01

    Coupling between neural oscillations in different frequency bands has been proposed to coordinate neural processing. In particular, gamma power coupled to alpha phase is proposed to reflect gating of information in the visual system but the existence of such a mechanism remains untested. Here, we recorded ongoing brain activity using magnetoencephalography in subjects who performed a modified Sternberg working memory task in which distractors were presented in the retention interval. During the anticipatory pre-distractor period, we show that the phase of alpha oscillations was coupled with the power of high (80-120Hz) gamma band activity, i.e. gamma power consistently was lower at the trough than at the peak of the alpha cycle (9-12Hz). We further show that high alpha power was associated with weaker gamma power at the trough of the alpha cycle. This result is in line with alpha activity in sensory region implementing a mechanism of pulsed inhibition silencing neuronal firing every ~100 ms. PMID:26039691

  17. The activation mechanism of alpha1beta2gamma2S and alpha3beta3gamma2S GABAA receptors.

    PubMed

    Keramidas, Angelo; Harrison, Neil L

    2010-01-01

    The alpha1beta2gamma2 and alpha3beta3gamma2 are two isoforms of gamma-aminobutyric acid type A (GABAA) receptor that are widely distributed in the brain. Both are found at synapses, for example in the thalamus, where they mediate distinctly different inhibitory postsynaptic current profiles, particularly with respect to decay time. The two isoforms were expressed in HEK293 cells, and single-channel activity was recorded from outside-out patches. The kinetic characteristics of both isoforms were investigated by analyzing single-channel currents over a wide range of GABA concentrations. Alpha1beta2gamma2 channels exhibited briefer active periods than alpha3beta3gamma2 channels over the entire range of agonist concentrations and had lower intraburst open probabilities at subsaturating concentrations. Activation mechanisms were constructed by fitting postulated schemes to data recorded at saturating and subsaturating GABA concentrations simultaneously. Reaction mechanisms were ranked according to log-likelihood values and how accurately they simulated ensemble currents. The highest ranked mechanism for both channels consisted of two sequential binding steps, followed by three conducting and three nonconducting configurations. The equilibrium dissociation constant for GABA at alpha3beta3gamma2 channels was approximately 2.6 microM compared with approximately 19 microM for alpha1beta2gamma2 channels, suggesting that GABA binds to the alpha3beta3gamma2 channels with higher affinity. A notable feature of the mechanism was that two consecutive doubly liganded shut states preceded all three open configurations. The lifetime of the third shut state was briefer for the alpha3beta3gamma2 channels. The longer active periods, higher affinity, and preference for conducting states are consistent with the slower decay of inhibitory currents at synapses that contain alpha3beta3gamma2 channels. The reaction mechanism we describe here may also be appropriate for the analysis of other

  18. Time course of lipolytic activity and lipid peroxidation after whole-body gamma irradiation of rats

    SciTech Connect

    Rejholcova, M.; Wilhelm, J.

    1989-01-01

    The content of fluorescing products of lipid peroxidation (LFP) and hormone-stimulated lipolytic activity were determined in rat epididymal adipose tissue during a 29-day interval after whole-body gamma irradiation. An increase in LFP was accompanied by a decrease in lipolytic activity. It is suggested that these effects are interrelated and that the decrease in lipolysis in irradiated, semi fasting rats is an additional deteriorating factor leading to death in some animals.

  19. Anti-diabetic action of Punica granatum flower extract: Activation of PPAR-{gamma} and identification of an active component

    SciTech Connect

    Huang, Tom H.W.; Peng Gang; Kota, Bhavani P.; Li, George Q.; Yamahara, Johji; Roufogalis, Basil D.; Li Yuhao . E-mail: yuhao@pharm.usyd.edu.au

    2005-09-01

    Peroxisome proliferator-activated receptor (PPAR)-{gamma} activators are widely used in the treatment of type 2 diabetes because they improve the sensitivity of insulin receptors. Punica granatum flower (PGF) has been used as an anti-diabetic medicine in Unani medicinal literature. The mechanism of actions is, however, unknown. In the current study, we demonstrated that 6-week oral administration of methanol extract from PGF (500 mg/kg, daily) inhibited glucose loading-induced increase of plasma glucose levels in Zucker diabetic fatty rats (ZDF), a genetic animal model for type 2 diabetes, whereas it did not inhibit the increase in Zucker lean rats (ZL). The treatment did not lower the plasma glucose levels in fasted ZDF and ZL rats. Furthermore, RT-PCR results demonstrated that the PGF extract treatment in ZDF rats enhanced cardiac PPAR-{gamma} mRNA expression and restored the down-regulated cardiac glucose transporter (GLUT)-4 (the insulin-dependent isoform of GLUTs) mRNA. These results suggest that the anti-diabetic activity of PGF extract may result from improved sensitivity of the insulin receptor. From the in vitro studies, we demonstrated that the PGF extract enhanced PPAR-{gamma} mRNA and protein expression and increased PPAR-{gamma}-dependent mRNA expression and activity of lipoprotein lipase in human THP-1-differentiated macrophage cells. Phytochemical investigation demonstrated that gallic acid in PGF extract is mostly responsible for this activity. Thus, our findings indicate that PPAR-{gamma} is a molecular target for PGF extract and its prominent component gallic acid, and provide a better understanding of the potential mechanism of the anti-diabetic action of PGF.

  20. Anti-diabetic action of Punica granatum flower extract: activation of PPAR-gamma and identification of an active component.

    PubMed

    Huang, Tom H W; Peng, Gang; Kota, Bhavani P; Li, George Q; Yamahara, Johji; Roufogalis, Basil D; Li, Yuhao

    2005-09-01

    Peroxisome proliferator-activated receptor (PPAR)-gamma activators are widely used in the treatment of type 2 diabetes because they improve the sensitivity of insulin receptors. Punica granatum flower (PGF) has been used as an anti-diabetic medicine in Unani medicinal literature. The mechanism of actions is, however, unknown. In the current study, we demonstrated that 6-week oral administration of methanol extract from PGF (500 mg/kg, daily) inhibited glucose loading-induced increase of plasma glucose levels in Zucker diabetic fatty rats (ZDF), a genetic animal model for type 2 diabetes, whereas it did not inhibit the increase in Zucker lean rats (ZL). The treatment did not lower the plasma glucose levels in fasted ZDF and ZL rats. Furthermore, RT-PCR results demonstrated that the PGF extract treatment in ZDF rats enhanced cardiac PPAR-gamma mRNA expression and restored the down-regulated cardiac glucose transporter (GLUT)-4 (the insulin-dependent isoform of GLUTs) mRNA. These results suggest that the anti-diabetic activity of PGF extract may result from improved sensitivity of the insulin receptor. From the in vitro studies, we demonstrated that the PGF extract enhanced PPAR-gamma mRNA and protein expression and increased PPAR-gamma-dependent mRNA expression and activity of lipoprotein lipase in human THP-1-differentiated macrophage cells. Phytochemical investigation demonstrated that gallic acid in PGF extract is mostly responsible for this activity. Thus, our findings indicate that PPAR-gamma is a molecular target for PGF extract and its prominent component gallic acid, and provide a better understanding of the potential mechanism of the anti-diabetic action of PGF. PMID:16102567

  1. Altered polymorphonuclear leukocyte Fc gamma R expression contributes to decreased candicidal activity during intraabdominal sepsis

    SciTech Connect

    Simms, H.H.; D'Amico, R.; Monfils, P.; Burchard, K.W. )

    1991-03-01

    We investigated the effects of untreated intraabdominal sepsis on polymorphonuclear leukocyte (PMN) candicidal activity. Two groups of swine were studied. Group I (n=6) underwent sham laparotomy, group II (n=7) underwent cecal ligation and incision. Untreated intraabdominal sepsis resulted in a progressive decrease in PMN candicidal activity. Concomitant rosetting and phagocytosis assays demonstrated a decrease in both the attachment and phagocytosis of Candida albicans opsonized with both normal and septic swine serum by PMNs in group II. Iodine 125-labeled swine immunoglobulin G (IgG) and fluorescein isothioalanate (FITC)-labeled swine IgG were used to investigate Fc gamma receptor ligand interactions. Scatchard analyses demonstrated a progressive decline in both the binding affinity constant and number of IgG molecules bound per PMN. Stimulation of the oxidative burst markedly reduced 125I-labeled IgG binding in both group I and group II, with a greater decrement being seen in animals with intraabdominal sepsis. Further, in group II, PMN recycling of the Fc gamma receptor to the cell surface after generation of the oxidative burst was reduced by postoperative day 4. Binding of monoclonal antibodies to Fc gamma receptor II, but not Fc gamma receptor I/III markedly reduced intracellular candicidal activity. Immunofluorescence studies revealed a homogeneous pattern of FITC-IgG uptake by nearly all group I PMNs, whereas by postoperative day 8 a substantial number of PMNs from group II failed to internalize the FITC-IgG. These studies suggest that untreated intraabdominal sepsis reduces PMN candicidal activity and that this is due, in part, to altered PMN Fc gamma receptor ligand interactions.

  2. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    SciTech Connect

    Firestone, Richard B; English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Leung, Ka-Ngo; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-02-13

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents.1-3. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity.

  3. Identification of estrogenic activity change in sewage, industrial and livestock effluents by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Ahn, Byeong-Yong; Kang, Sung-Wook; Yoo, Jisu; Kim, Woong-Ki; Bae, Paek-Hyun; Jung, Jinho

    2012-11-01

    In this study, reduction of estrogenic activity in three different types of effluents from sewage, industrial and livestock wastewater treatment plants by gamma-irradiation was investigated using the yeast two-hybrid assay. After gamma-ray treatment at a dose of 10 kGy, estrogenic activities of sewage, industrial and livestock effluents decreased from 4.4 to 3.0, 1.5 to 1.0 and 16 to 9.9 ng-EEQ L-1, respectively. The substantial reduction of estrogenic activity in livestock effluent was attributable to the degradation of 17β-estradiol (E2), estrone (E1) and 17α-ethynylestradiol (EE2). Although bisphenol A (BPA) was found at the highest concentration in all effluents, its contribution to the estrogenic activity was not significant due to its low relative estrogenic potency. Meanwhile, the calculated estrogenic activity based on concentrations of E2, E1, EE2 and BPA in the effluents significantly differed from the measured ones. Overestimation may have resulted by dissolved organic matters in effluents inhibiting the estrogenic activity of E2, E1, EE2 and BPA, whereas underestimation was likely due to estrogenic by-products generated by gamma-irradiation.

  4. The use of an active coded aperture for improved directional measurements in high energy gamma-ray astronomy

    NASA Technical Reports Server (NTRS)

    Johansson, A.; Beron, B. L.; Campbell, L.; Eichler, R.; Hofstadter, R.; Hughes, E. B.; Wilson, S.; Gorodetsky, P.

    1980-01-01

    The coded aperture, a refinement of the scatter-hole camera, offers a method for the improved measurement of gamma-ray direction in gamma-ray astronomy. Two prototype coded apertures have been built and tested. The more recent of these has 128 active elements of the heavy scintillator BGO. Results of tests for gamma-rays in the range 50-500 MeV are reported and future application in space discussed.

  5. Chronic stimulation of cultured neuronal networks boosts low-frequency oscillatory activity at theta and gamma with spikes phase-locked to gamma frequencies

    NASA Astrophysics Data System (ADS)

    Leondopulos, Stathis S.; Boehler, Michael D.; Wheeler, Bruce C.; Brewer, Gregory J.

    2012-04-01

    Slow wave oscillations in the brain are essential for coordinated network activity but have not been shown to self-organize in vitro. Here, the development of dissociated hippocampal neurons into an active network with oscillations on multi-electrode arrays was evaluated in the absence and presence of chronic external stimulation. Significant changes in signal power were observed in the range of 1-400 Hz with an increase in amplitude during bursts. Stimulation increased oscillatory activity primarily in the theta (4-11 Hz) and slow gamma (30-55 Hz) bands. Spikes were most prominently phase-locked to the slow gamma waves. Notably, the dissociated network self-organized to exhibit sustained delta, theta, beta and gamma oscillations without input from cortex, thalamus or organized pyramidal cell layers.

  6. Interferon gamma regulates accumulation of the proteasome activator PA28 and immunoproteasomes at nuclear PML bodies.

    PubMed

    Fabunmi, R P; Wigley, W C; Thomas, P J; DeMartino, G N

    2001-01-01

    PA28 is an interferon (gamma) (IFN(gamma)) inducible proteasome activator required for presentation of certain major histocompatibility (MHC) class I antigens. Under basal conditions in HeLa and Hep2 cells, a portion of nuclear PA28 is concentrated at promyelocytic leukemia oncoprotein (PML)-containing bodies also commonly known as PODs or ND10. IFN(gamma) treatment greatly increased the number and size of the PA28- and PML-containing bodies, and the effect was further enhanced in serum-deprived cells. PML bodies are disrupted in response to certain viral infections and in diseases such as acute promyelocytic leukemia (APL). Like PML, PA28 was delocalized from PML bodies by expression of the cytomegalovirus protein, IE1, and in NB4 cells, an APL model line. Moreover, retinoic acid treatment, which causes remission of APL in patients and reformation of PML-containing bodies in NB4 cells, relocalized PA28 to this site. In contrast, the proteasome, the functional target of PA28, was not detected at PML bodies under basal conditions in HeLa and Hep2 cells, but IFN(gamma) promoted accumulation of 'immunoproteasomes' at this site. These results establish PA28 as a novel component of nuclear PML bodies, and suggest that PA28 may assemble or activate immunoproteasomes at this site as part of its role in proteasome-dependent MHC class I antigen presentation. PMID:11112687

  7. Telmisartan prevented cognitive decline partly due to PPAR-{gamma} activation

    SciTech Connect

    Mogi, Masaki; Li Jianmei; Tsukuda, Kana; Iwanami, Jun; Min, Li-Juan; Sakata, Akiko; Fujita, Teppei; Iwai, Masaru; Horiuchi, Masatsugu

    2008-10-24

    Telmisartan is a unique angiotensin receptor blocker (ARB) and partial agonist of peroxisome proliferator-activated receptor (PPAR)-{gamma}. Here, we investigated the preventive effect of telmisartan on cognitive decline in Alzheimer disease. In ddY mice, intracerebroventricular injection of A{beta} 1-40 significantly attenuated their cognitive function evaluated by shuttle avoidance test. Pretreatment with a non-hypotensive dose of telmisartan significantly inhibited such cognitive decline. Interestingly, co-treatment with GW9662, a PPAR-{gamma} antagonist, partially inhibited this improvement of cognitive decline. Another ARB, losartan, which has less PPAR-{gamma} agonistic effect, also inhibited A{beta}-injection-induced cognitive decline; however the effect was smaller than that of telmisartan and was not affected by GW9662. Immunohistochemical staining for A{beta} showed the reduced A{beta} deposition in telmisartan-treated mice. However, this reduction was not observed in mice co-administered GW9662. These findings suggest that ARB has a preventive effect on cognitive impairment in Alzheimer disease, and telmisartan, with PPAR-{gamma} activation, could exert a stronger effect.

  8. Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

    NASA Technical Reports Server (NTRS)

    Shih, K. L.; Souza, K. A.

    1978-01-01

    The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

  9. Radioactivity of Potassium Solutions: A Comparison of Calculated Activity to Measured Activity from Gross Beta Counting and Gamma Spectroscopy

    SciTech Connect

    Gaylord, R F

    2005-07-26

    In order to determine if the measured beta activity for a solution containing potassium was exactly as predicted, particularly since the CES gas counter is not calibrated specifically with K-40, an experiment was conducted to compare measured activities from two radioanalytical methods (gamma spectroscopy and gas proportional counting) to calculated activities across a range of potassium concentrations. Potassium, being ubiquitous and naturally radioactive, is a well-known and common interference in gross beta counting methods. By measuring the observed beta activity due to K-40 in potassium-containing solutions across a wide range of concentrations, it was found that the observed beta activity agrees well with the beta activity calculated from the potassium concentration measured by standard inorganic analytical techniques, such as ICP-OES, and that using the measured potassium concentration to calculate the expected beta activity, and comparing this to the observed beta activity to determine if potassium can account for all the observed activity in a sample, is a valid technique. It was also observed that gamma spectroscopy is not an effective means of measuring K-40 activity below approximately 700 pCi/L, which corresponds to a solution with approximately 833 mg/L total potassium. Gas proportional counting for gross beta activity has a much lower detection limit, typically 20-50 picoCi/L for a liquid low in total dissolved solids, which corresponds to a potassium concentration of approximately 30-70 ppm K.

  10. Characterization of the human activator protein-2gamma (AP-2gamma) gene: control of expression by Sp1/Sp3 in breast tumour cells.

    PubMed Central

    Hasleton, Mark D; Ibbitt, J Claire; Hurst, Helen C

    2003-01-01

    The activator protein-2 (AP-2) family of DNA-binding transcription factors are developmentally regulated and also play a role in human neoplasia. In particular, the AP-2gamma protein has been shown to be overexpressed in a high percentage of breast tumours. In the present study, we report the complete sequence determination of the human TFAP2C gene encoding the AP-2gamma transcription factor plus the mapping of the transcription start site used in breast tumour-derived cells. The 5'-end of the gene lies within a CpG island and transcription is initiated at a single site within a classical initiator motif. We have gone on to investigate why some breast tumour-derived cell lines readily express AP-2gamma, whereas others do not, and show that the proximal promoter (+191 to -312) is differentially active in the two cell phenotypes. DNase footprinting led to the identification of three Sp1/Sp3-binding sites within this region, two of which are absolutely required both for promoter function and cell-type-specific activity. By Western blotting a panel of expressing and non-expressing breast tumour lines we show that the latter have higher levels of Sp3. Furthermore, increasing Sp3 levels in AP-2gamma-expressing cells led to the repression of AP-2gamma promoter activity, particularly when Sp3 inhibitory function was maximized through sumoylation. We propose that differences in the level and activity of Sp3 between breast tumour lines can determine the expression level of their AP-2gamma gene. PMID:12733991

  11. Active galactic nuclei at gamma-ray energies

    NASA Astrophysics Data System (ADS)

    Dermer, Charles Dennison; Giebels, Berrie

    2016-06-01

    Active Galactic Nuclei can be copious extragalactic emitters of MeV-GeV-TeV γ rays, a phenomenon linked to the presence of relativistic jets powered by a super-massive black hole in the center of the host galaxy. Most of γ-ray emitting active galactic nuclei, with more than 1500 known at GeV energies, and more than 60 at TeV energies, are called "blazars". The standard blazar paradigm features a jet of relativistic magnetized plasma ejected from the neighborhood of a spinning and accreting super-massive black hole, close to the observer direction. Two classes of blazars are distinguished from observations: the flat-spectrum radio-quasar class (FSRQ) is characterized by strong external radiation fields, emission of broad optical lines, and dust tori. The BL Lac class (from the name of one of its members, BL Lacertae) corresponds to weaker advection-dominated flows with γ-ray spectra dominated by the inverse Compton effect on synchrotron photons. This paradigm has been very successful for modeling the broadband spectral energy distributions of blazars. However, many fundamental issues remain, including the role of hadronic processes and the rapid variability of a few FSRQs and several BL Lac objects whose synchrotron spectrum peaks at UV or X-ray frequencies. A class of γ-ray-emitting radio galaxies, which are thought to be the misaligned counterparts of blazars, has emerged from the results of the Fermi-Large Area Telescope and of ground-based Cherenkov telescopes. Soft γ-ray emission has been detected from a few nearby Seyfert galaxies, though it is not clear whether those γ rays originate from the nucleus. Blazars and their misaligned counterparts make up most of the ≳100 MeV extragalactic γ-ray background (EGB), and are suspected of being the sources of ultra-high energy cosmic rays. The future "Cherenkov Telescope Array", in synergy with the Fermi-Large Area Telescope and a wide range of telescopes in space and on the ground, will write the next chapter

  12. Interaction of ultraviolet and X-ray radiation with gamma rays produced by a jet in active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Zbyszewska, Magda

    1994-01-01

    Recent observations by the Compton Gamma-Ray Observatory give evidence for the existence of a type of blazar with strong gamma-ray emission. Data obtained by EGRET for the quasar 3C 279 show a spectrum between 100 MeV and 10 GeV. Photons of such energies should interact with the X-rays and produce positron/electron pairs. If the optical depth against pair production for the gamma rays is large (tau(gamma gamma) greater than 1), the gamma-ray spectrum should be affected. The importance of this process has been pointed out by, e.g., Maraschi, Ghisellini, & Celotti (1992). Several works (e.g., Dermer 1993; Zbyszewska 1993; Sikora, Begelman, & Rees 1993) concerning gamma-ray radiation from quasar 3C 279 have proposed a model in which the gamma rays are produced via interaction between a moving cloud of relativistic electrons and external soft photons. The presence of gamma rays in active galactic nuclei spectra gives constraints on the localization and the luminosity of the medium which produces ultraviolet/X-ray photons. We investigate what conditions should be fulfilled in the above model to avoid the absorption of the gamma rays due to pair production.

  13. Telmisartan protects against diabetic vascular complications in a mouse model of obesity and type 2 diabetes, partially through peroxisome proliferator activated receptor-{gamma}-dependent activity

    SciTech Connect

    Toyama, Kensuke; Nakamura, Taishi; Kataoka, Keiichiro; Yasuda, Osamu; Fukuda, Masaya; Tokutomi, Yoshiko; Dong, Yi-Fei; Ogawa, Hisao; Kim-Mitsuyama, Shokei

    2011-07-08

    Highlights: {yields} Telmisartan, an angiotensin receptor blocker, acts as a partial PPAR{gamma} agonist. {yields} The protective effects of telmisartan against diabetic vascular injury were associated with attenuation of vascular NF{kappa}B activation and TNF {alpha}. {yields} PPAR{gamma} activity of telmisartan was involved in the normalization of vascular PPAR{gamma} downregulation in diabetic mice. {yields} We provided the first evidence indicating that PPAR{gamma} activity of telmisartan contributed to the protective effects of telmisartan against diabetic vascular complication. -- Abstract: Experimental and clinical data support the notion that peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) activation is associated with anti-atherosclerosis as well as anti-diabetic effect. Telmisartan, an angiotensin receptor blocker (ARB), acts as a partial PPAR{gamma} agonist. We hypothesized that telmisartan protects against diabetic vascular complications, through PPAR{gamma} activation. We compared the effects of telmisartan, telmisartan combined with GW9662 (a PPAR{gamma} antagonist), and losartan with no PPAR{gamma} activity on vascular injury in obese type 2 diabetic db/db mice. Compared to losartan, telmisartan significantly ameliorated vascular endothelial dysfunction, downregulation of phospho-eNOS, and coronary arterial remodeling in db/db mice. More vascular protective effects of telmisartan than losartan were associated with greater anti-inflammatory effects of telmisartan, as shown by attenuation of vascular nuclear factor kappa B (NF{kappa}B) activation and tumor necrosis factor {alpha}. Coadministration of GW9662 with telmisartan abolished the above mentioned greater protective effects of telmisartan against vascular injury than losartan in db/db mice. Thus, PPAR{gamma} activity appears to be involved in the vascular protective effects of telmisartan in db/db mice. Moreover, telmisartan, but not losartan, prevented the downregulation of

  14. Intercomparison of activity size distributions of thoron progeny by alpha- and gamma-counting methods.

    PubMed

    Cheng, Y S; Yu, C C; Tu, K W

    1994-01-01

    It is difficult to calibrate sampling devices using radon or thoron progeny or particles measuring 1-4 nm; therefore, an interlaboratory comparison is important to verify the performance of graded diffusion batteries for the activity size distributions of the "unattached" progeny. This paper describes the results of an interlaboratory comparison of 220Rn progeny size distributions using graded diffusion batteries by alpha- and gamma-counting methods with different data inversion schemes. Graded diffusion batteries designed at the Inhalation Toxicology Research Institute and at the Environmental Measurement Laboratory were used in the study. Screens and backup filters from the Environmental Measurement Laboratory-graded diffusion batteries were counted simultaneously in alpha counters for total alpha activities, and those of the Inhalation Toxicology Research Institute-graded diffusion batteries were counted in a gamma detector for gamma activities from 212Pb. Because of the different counting methods and data analysis procedures used, this interlaboratory study of 220Rn progeny allows a more rigorous way of testing instrument performance. 212Pb particles generated in well-controlled environments of oxygen, nitrogen, or oxygen with 1 ppm of nitrogen oxide were measured. In general, good agreement in activity size distributions was obtained from these two methods. Some differences observed in individual size spectra were attributable to the data inversion programs used in each laboratory. When the data were analyzed by the same computer program, most differences disappeared. PMID:8253581

  15. Activity determination, kinetic analyses and isoenzyme identification of gamma glutamyltransferase in human neutrophils.

    PubMed

    Sener, Azize; Yardimci, Turay

    2005-05-31

    Gamma-glutamyltransferase (GGT, EC 2.3.2.2) which hydrolyzes glutathione (GSH), is required for the maintenance of normal intracellular GSH concentration. GGT is a membrane enzyme present in leukocytes and platelets. Its activity has also been observed in human neutrophils. In this study, GGT was purified from Triton X-100 solubilized neutrophils and its kinetic parameters were determined. For kinetic analyses of transpeptidation reaction, gamma-glutamyl p-nitroanilide was used as the substrate and glycylglycine as the acceptor. Apparent K(m) values were determined as 1.8 mM for gamma-glutamyl p-nitroanilide and 16.9 mM for glycylglycine. The optimum pH of GGT activity was 8.2 and the optimum temperature was 37 degrees C. It had thermal stability with 58 % relative activity at 56 degrees C for 30 min incubation. L-serine, in the presence of borate, was detected as the competitive inhibitor. Bromcresol green inhibited neutrophil GGT activity as a noncompetitive inhibitor. The neutrophils seem to contain only the isoenzyme that is present in platelets. We characterized the kinetic properties and compared the type of the isoenzyme of neutrophil GGT with platelet GGT via polyacrylamide gel electrophoresis (PAGE) under a standard set of conditions. PMID:15943911

  16. Cellular and circuit models of increased resting-state network gamma activity in schizophrenia.

    PubMed

    White, R S; Siegel, S J

    2016-05-01

    Schizophrenia (SCZ) is a disorder characterized by positive symptoms (hallucinations, delusions), negative symptoms (blunted affect, alogia, reduced sociability, and anhedonia), as well as persistent cognitive deficits (memory, concentration, and learning). While the biology underlying subjective experiences is difficult to study, abnormalities in electroencephalographic (EEG) measures offer a means to dissect potential circuit and cellular changes in brain function. EEG is indispensable for studying cerebral information processing due to the introduction of techniques for the decomposition of event-related activity into its frequency components. Specifically, brain activity in the gamma frequency range (30-80Hz) is thought to underlie cognitive function and may be used as an endophenotype to aid in diagnosis and treatment of SCZ. In this review we address evidence indicating that there is increased resting-state gamma power in SCZ. We address how modeling this aspect of the illness in animals may help treatment development as well as providing insights into the etiology of SCZ. PMID:26577758

  17. Active Neutron and Gamma Ray Instrumentation for In Situ Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    The Pulsed Neutron Generator-Gamma Ray And Neutron Detectors (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA-GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Menus, asteroids, comets and the satellites of the outer planets. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions and, especially its the case of the Mars Odyssey GRS, have contributed detailed maps of the elemental composition over the entire surface of Mars. However, orbital gamma ray measurements have low spatial sensitivity (100's of km) due to their low surface emission rates from cosmic rays and subsequent need to be averaged over large surface areas. PNG-GRAND overcomes this impediment by incorporating a powerful neutron excitation source that permits high sensitivity surface and subsurface measurements of bulk elemental compositions. PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument to determine subsurface elemental composition without needing to drill into a planet's surface a great advantage in mission design. We are currently testing PNG-GRAND prototypes at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 in x 1 m granite structure placed outdoors in an empty field. Because an independent trace elemental analysis has been performed on the material, this granite sample is a known standard with which to compare both Monte Carlo simulations and our experimentally measured elemental composition data. We will present data from operating PNG-GRAND in various experimental configurations on a

  18. Phenotypic and functional characteristics of active suppressor cells against IFN-gamma production in PHA-stimulated cord blood lymphocytes

    SciTech Connect

    Seki, H.; Taga, K.; Matsuda, A.; Uwadana, N.; Hasui, M.; Miyawaki, T.; Taniguchi, N.

    1986-11-15

    Cord blood mononuclear cells (MNC) were defective in their ability to produce interferon-gamma (IFN-gamma) on stimulation with phytohemagglutinin (PHA) or recombinant interleukin 2, whereas cord MNC could induce comparable amounts of IFN-gamma with adult controls on stimulation with a streptococcal preparation, OK-432. Moreover, irradiation of cord MNC with 1500 rad before PHA stimulation could restore the IFN-gamma production. Kinetic studies indicated that such augmentation of IFN-gamma production by irradiation was evident when cord MNC were irradiated before or by 12 hr of PHA-stimulated culture. But irradiation after 18 hr or more of PHA stimulation did not exert any significant augmentation on IFN-gamma production by cord MNC. It seemed most likely that the ability of IFN-gamma production is already mature at birth, but radiosensitive suppressor effectors on IFN-gamma production are activated within cord MNC at an early stage of PHA stimulation, resulting in poor IFN-gamma production by cord MNC. PHA-induced IFN-gamma production by OKT3+, OKT4+, and OKT8- cord cells were markedly enhanced by irradiation with 1,500 rad before the culture. Coculture experiments disclosed that cord OKT4+ cells, but not OKT4- cells, when prestimulated with PHA for 24 hr, exerted active suppression on PHA-induced IFN-gamma production by adult MNC in a dose-dependent manner. These results suggested that radiosensitive suppressor effectors on IFN-gamma production were induced within the OKT4+ T cell subset of cord MNC on PHA stimulation.

  19. Transitions, cross sections and neutron binding energy in 186Re by Prompt Gamma Activation Analysis

    NASA Astrophysics Data System (ADS)

    Lerch, A. G.; Hurst, A. M.; Firestone, R. B.; Revay, Zs.; Szentmiklosi, L.; McHale, S. R.; McClory, J. W.; Detwiler, B.; Carroll, J. J.

    2014-03-01

    The nuclide 186Re possesses an isomer with 200,000 year half-life while its ground state has a half-life of 3.718 days. It is also odd-odd and well-deformed nucleus, so should exhibit a variety of other interesting nuclear-structure phenomena. However, the available nuclear data is rather sparse; for example, the energy of the isomer is only known to within + 7 keV and, with the exception of the J?=1- ground state, every proposed level is tentative in the ENSDF. Previously, Prompt Gamma Activation Analysis (PGAA) was utilized to study natRe with 186,188Re being produced via thermal neutron capture. Recently, an enriched 185Re target was irradiated by thermal neutrons at the Budapest Research Reactor to build on those results. Prompt (primary and secondary) and delayed gamma-ray transitions were measured with a large-volume, Compton-suppressed HPGe detector. Absolute cross sections for each gamma transition were deduced and corrected for self attenuation within the sample. Fifty-two primary gamma-ray transitions were newly identified and used to determine a revised value of the neutron binding energy. DICEBOX was used to simulate the decay scheme and the total radiative thermal neutron capture cross section was found to be 97+/-3 b Supported by DTRA (Detwiler) through HDTRA1-08-1-0014.

  20. Gamma-ray active galactic nucleus type through machine-learning algorithms

    NASA Astrophysics Data System (ADS)

    Hassan, T.; Mirabal, N.; Contreras, J. L.; Oya, I.

    2013-01-01

    The Fermi Gamma-ray Space Telescope (Fermi) is producing the most detailed inventory of the gamma-ray sky to date. Despite tremendous achievements approximately 25 per cent of all Fermi extragalactic sources in the Second Fermi Large Area Telescope Catalogue (2FGL) are listed as active galactic nuclei (AGN) of uncertain type. Typically, these are suspected blazar candidates without a conclusive optical spectrum or lacking spectroscopic observations. Here, we explore the use of machine-learning algorithms - random forests and support vector machines - to predict specific AGN subclass based on observed gamma-ray spectral properties. After training and testing on identified/associated AGN from the 2FGL we find that 235 out of 269 AGN of uncertain type have properties compatible with gamma-ray BL Lacertae and flat-spectrum radio quasars with accuracy rates of 85 per cent. Additionally, direct comparison of our results with class predictions made after following the infrared colour-colour space of Massaro et al. shows that the agreement rate is over four-fifths for 54 overlapping sources, providing independent cross-validation. These results can help tailor follow-up spectroscopic programmes and inform future pointed surveys with ground-based Cherenkov telescopes.

  1. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    SciTech Connect

    Staples, P.; Prettyman, T.; Lestone, J.

    1998-12-01

    The authors have used a tomographic gamma scanner (TGS) to produce tomographic prompt gamma-ray neutron activation analysis imaging (PGNAA) of heterogeneous matrices. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. The authors are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis (NDA) technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source-to-sample coupling term. To assist in the determination of the coupling term, the authors have obtained images for a range of sample that are very well characterized, such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. They then compare the measurements to MCNP calculations. For an accurate quantitative measurement, it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes.

  2. Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone attenuates postincisional pain by regulating macrophage polarization

    SciTech Connect

    Hasegawa-Moriyama, Maiko; Ohnou, Tetsuya; Godai, Kohei; Kurimoto, Tae; Nakama, Mayo; Kanmura, Yuichi

    2012-09-14

    Highlights: Black-Right-Pointing-Pointer Rosiglitazone attenuated postincisional pain. Black-Right-Pointing-Pointer Rosiglitazone alters macrophage polarization to F4/80{sup +}CD206{sup +} M2 macrophages at the incisional sites. Black-Right-Pointing-Pointer Transplantation of rosiglitazone-treated macrophages produced analgesic effects. -- Abstract: Acute inflammation triggered by macrophage infiltration to injured tissue promotes wound repair and may induce pain hypersensitivity. Peroxisome proliferator-activated receptor {gamma} (PPAR){gamma} signaling is known to regulate heterogeneity of macrophages, which are often referred to as classically activated (M1) and alternatively activated (M2) macrophages. M1 macrophages have considerable antimicrobial activity and produce a wide variety of proinflammatory cytokines. In contrast, M2 macrophages are involved in anti-inflammatory and homeostatic functions linked to wound healing and tissue repair. Although it has been suggested that PPAR{gamma} agonists attenuate pain hypersensitivity, the molecular mechanism of macrophage-mediated effects of PPAR{gamma} signaling on pain development has not been explored. In this study, we investigated the link between the phenotype switching of macrophage polarization induced by PPAR{gamma} signaling and the development of acute pain hypersensitivity. Local administration of rosiglitazone significantly ameliorated hypersensitivity to heat and mechanical stimuli, and paw swelling. Consistent with the down-regulation of nuclear factor {kappa}B (NF{kappa}B) phosphorylation by rosiglitazone at the incisional sites, the number of F4/80{sup +}iNOS{sup +} M1 macrophages was decreased whereas numbers of F4/80{sup +}CD206{sup +} M2 macrophages were increased in rosiglitazone-treated incisional sites 24 h after the procedure. In addition, gene induction of anti-inflammatory M2-macrophage-associated markers such as arginase1, FIZZ1 and interleukin (IL)-10 were significantly increased, whereas

  3. Interferon-gamma-dependent cytotoxic activation of human astrocytes and astrocytoma cells.

    PubMed

    Hashioka, Sadayuki; Klegeris, Andis; Schwab, Claudia; McGeer, Patrick L

    2009-12-01

    Astrocytes and microglia become activated in a broad spectrum of inflammatory neurodegenerative diseases. Activated microglia are widely believed to be the principal source of inflammation-induced neuronal degeneration in these disorders. To investigate the neurotoxic potential of human astrocytes, we exposed them and human astrocytic U-373 MG cells to a variety of inflammatory stimulants. We then assessed the effects of their supernatants on human SH-SY5 cells. When astrocytes and U-373 MG cells were stimulated with interferon (IFN)-gamma (150U/ml), their supernatants significantly reduced SH-SY5Y cell viability. Other powerful inflammatory stimulants such as lipopolysaccharide (0.5mug/ml), tumor necrosis factor-alpha (10ng/ml) and interleukin-1beta (10ng/ml), alone or in combination, were without effect. These combinations were also unable to enhance the IFN-gamma effect. The induced cytotoxicities were reversed by JAK inhibitor I, a potent and specific inhibitor of JAKs. This result indicates that the neurotoxic effect was proceeding through the IFN-gamma receptor (IFNGR)-JAK-STAT intracellular pathway. To establish that the IFNGR is expressed on both cultured astrocytes and U-373 MG cells, we performed RT-PCR on total RNA extracts to identify a specific IFNGR product. We showed the protein product on these cultured cells by immunocytochemistry using an antibody to IFNGR. Finally, using human postmortem material, we showed sharp upregulation of the IFNGR on activated astrocytes in affected areas in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. These findings suggest that activated astrocytes may become neurotoxic when stimulated by IFN-gamma and may therefore exacerbate the pathology in a spectrum of neurodegenerative diseases. PMID:18375019

  4. Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

    DOEpatents

    Smith, Donald L.; Ikeda, Yujiro; Uno, Yoshitomo

    1996-01-01

    Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the .sup.16 O(n,p).sup.16 N reaction using .sup.14 -MeV neutrons produced at the neutron source via the .sup.3 H(d,n).sup.4 He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second .sup.16 N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1-2 minutes.

  5. Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

    DOEpatents

    Smith, D.L.; Ikeda, Yujiro; Uno, Yoshitomo

    1996-11-05

    Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the {sup 16}O(n,p){sup 16}N reaction using {sup 14}N-MeV neutrons produced at the neutron source via the {sup 3}H(d,n){sup 4}He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second {sup 16}N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1--2 minutes. 15 figs.

  6. Music training leads to the development of timbre-specific gamma band activity

    PubMed Central

    Shahin, Antoine J.; Roberts, Larry E.; Chau, Wilkin; Trainor, Laurel J.; Miller, Lee M.

    2015-01-01

    Oscillatory gamma band activity (GBA, 30–100Hz) has been shown to correlate with perceptual and cognitive phenomena including feature binding, template matching, and learning and memory formation. We hypothesized that if GBA reflects highly learned perceptual template matching, we should observe its development in musicians specific to the timbre of their instrument of practice. EEG was recorded in adult professional violinists and amateur pianists as well as in four- and five-year-old children studying piano in the Suzuki method before they commenced music lessons and one year later. The adult musicians showed robust enhancement of induced (non-time-locked) GBA, specifically to their instrument of practice, with the strongest effect in professional violinists. Consistent with this result, the children receiving piano lessons exhibited increased power of induced GBA for piano tones with one year of training, while children not taking lessons showed no effect. In comparison to induced GBA, evoked (time-locked) gamma band activity (30–90 Hz, ~80 ms latency) was present only in adult groups. Evoked GBA was more pronounced in musicians than non-musicians, with synchronization equally exhibited for violin and piano tones but enhanced for these tones compared to pure tones. Evoked gamma activity may index the physical properties of a sound and is modulated by acoustical training, while induced GBA may reflect higher perceptual learning and is shaped by specific auditory experiences. PMID:18375147

  7. Beta- and gamma-band activity reflect predictive coding in the processing of causal events.

    PubMed

    van Pelt, Stan; Heil, Lieke; Kwisthout, Johan; Ondobaka, Sasha; van Rooij, Iris; Bekkering, Harold

    2016-06-01

    In daily life, complex events are perceived in a causal manner, suggesting that the brain relies on predictive processes to model them. Within predictive coding theory, oscillatory beta-band activity has been linked to top-down predictive signals and gamma-band activity to bottom-up prediction errors. However, neurocognitive evidence for predictive coding outside lower-level sensory areas is scarce. We used magnetoencephalography to investigate neural activity during probability-dependent action perception in three areas pivotal for causal inference, superior temporal sulcus, temporoparietal junction and medial prefrontal cortex, using bowling action animations. Within this network, Granger-causal connectivity in the beta-band was found to be strongest for backward top-down connections and gamma for feed-forward bottom-up connections. Moreover, beta-band power in TPJ increased parametrically with the predictability of the action kinematics-outcome sequences. Conversely, gamma-band power in TPJ and MPFC increased with prediction error. These findings suggest that the brain utilizes predictive-coding-like computations for higher-order cognition such as perception of causal events. PMID:26873806

  8. Music training leads to the development of timbre-specific gamma band activity.

    PubMed

    Shahin, Antoine J; Roberts, Larry E; Chau, Wilkin; Trainor, Laurel J; Miller, Lee M

    2008-05-15

    Oscillatory gamma band activity (GBA, 30-100 Hz) has been shown to correlate with perceptual and cognitive phenomena including feature binding, template matching, and learning and memory formation. We hypothesized that if GBA reflects highly learned perceptual template matching, we should observe its development in musicians specific to the timbre of their instrument of practice. EEG was recorded in adult professional violinists and amateur pianists as well as in 4- and 5-year-old children studying piano in the Suzuki method before they commenced music lessons and 1 year later. The adult musicians showed robust enhancement of induced (non-time-locked) GBA, specifically to their instrument of practice, with the strongest effect in professional violinists. Consistent with this result, the children receiving piano lessons exhibited increased power of induced GBA for piano tones with 1 year of training, while children not taking lessons showed no effect. In comparison to induced GBA, evoked (time-locked) gamma band activity (30-90 Hz, approximately 80 ms latency) was present only in adult groups. Evoked GBA was more pronounced in musicians than non-musicians, with synchronization equally exhibited for violin and piano tones but enhanced for these tones compared to pure tones. Evoked gamma activity may index the physical properties of a sound and is modulated by acoustical training, while induced GBA may reflect higher perceptual learning and is shaped by specific auditory experiences. PMID:18375147

  9. The 124Sb activity standardization by gamma spectrometry for medical applications

    NASA Astrophysics Data System (ADS)

    de Almeida, M. C. M.; Iwahara, A.; Delgado, J. U.; Poledna, R.; da Silva, R. L.

    2010-07-01

    This work describes a metrological activity determination of 124Sb, which can be used as radiotracer, applying gamma spectrometry methods with hyper pure germanium detector and efficiency curves. This isotope with good activity and high radionuclidic purity is employed in the form of meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam) to treat leishmaniasis. 124Sb is also applied in animal organ distribution studies to solve some questions in pharmacology. 124Sb decays by β-emission and it produces several photons (X and gamma rays) with energy varying from 27 to 2700 keV. Efficiency curves to measure point 124Sb solid sources were obtained from a 166mHo standard that is a multi-gamma reference source. These curves depend on radiation energy, sample geometry, photon attenuation, dead time and sample-detector position. Results for activity determination of 124Sb samples using efficiency curves and a high purity coaxial germanium detector were consistent in different counting geometries. Also uncertainties of about 2% ( k=2) were obtained.

  10. Circulating gamma delta T cells are activated and depleted during progression of high-grade gliomas: Implications for gamma delta T cell therapy of GBM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glioblastoma multiforme (GBM) remains frustratingly impervious to any existing therapy. We have previously shown that GBM is sensitive to recognition and lysis by ex vivo activated gamma delta T cells, a minor subset of lymphocytes that innately recognize autologous stress-associated target antigens...

  11. Mycobacterium tuberculosis induces apoptosis in gamma/delta T lymphocytes from patients with advanced clinical forms of active tuberculosis.

    PubMed Central

    Duarte, R; Kindlelán, J M; Carracedo, J; Sánchez-Guijo, P; Ramírez, R

    1997-01-01

    Antigens from inactivated Mycobacterium tuberculosis H37Ra induce activation in a subpopulation of gamma/delta (gamma/delta) T lymphocytes in a manner that resembles that of superantigens from alpha/beta T cells. After culture in vitro with H37Ra proteins, gamma/delta T lymphocytes from patients with advanced clinical forms of active tuberculosis (ACF-TBC) display cytotoxic activity against homotypic target cells exposed to H37Ra. Cytotoxicity by gamma/delta T lymphocytes from ACF-TBC patients occurs in a range similar to that observed in healthy subjects. Following activation, H37Ra-stimulated gamma/delta T lymphocytes from healthy subjects did proliferate in the presence of exogenous recombinant human interleukin 2. However, under the same conditions, gamma/delta T lymphocytes from ACF-TBC patients not only did not proliferate but died by apoptosis. These results suggest that in gamma/delta T lymphocytes from patients with ACF-TBC, antigens from M. tuberculosis may induce cell activation that leads to apoptotic cell death. PMID:9008275

  12. Gamma irradiation: a method to produce an abiotic control for biological activated carbon.

    PubMed

    Stoquart, C; Vázquez-Rodríguez, G A; Servais, P; Barbeau, B

    2013-01-01

    The aim of this paper was to investigate the feasibility of using gamma irradiation to inhibit the microbial activity of biological powder activated carbon (PAC) without impacting its adsorptive properties. First of all, the range of dose of gamma rays required to produce abiotic PAC was selected on the basis of heterotrophic plate counts (HPC) inactivation and methylene blue (MB) adsorption kinetics. Doses inferior to 10 kGy were not sufficient to inhibit the culture of heterotrophic bacteria. On the other hand, doses superior to 15 kGy were demonstrated to affect the adsorption rate of MB. Consequently, a dose comprised between 10 and 15 kGy was selected for further investigation. In order to validate the adequacy of the range of dose (i.e. 10-15 kGy), adsorption characteristics were tested by monitoring the removal kinetics of refractory dissolved organic carbon (RDOC). No significant differences were observed between irradiated and non-irradiated biological PAC for the adsorption of RDOC. Irradiated, non-irradiated and virgin PAC were also evaluated in terms of abundance of viable (using the LIVE/DEAD BacLight method) bacteria and in terms of heterotrophic biomass activity. The results of the BacLight method demonstrated that attachment of the biofilm on the PAC was not impacted by the irradiation and heterotrophic activity measurements demonstrated that the latter could be radically reduced in the range of dose selected. In conclusion, when using a proper dose, the gamma irradiation of colonized activated carbon drastically reduced the heterotrophic activity on activated carbon without significantly impacting its adsorptive behaviour. PMID:24617066

  13. Structural and Biochemical Basis for the Binding Selectivity of Peroxisome Proliferator-activated Receptor [gamma] to PGC-1[alpha

    SciTech Connect

    Li, Yong; Kovach, Amanda; Suino-Powell, Kelly; Martynowski, Dariusz; Xu, H. Eric

    2008-07-23

    The functional interaction between the peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) and its coactivator PGC-1{alpha} is crucial for the normal physiology of PPAR{gamma} and its pharmacological response to antidiabetic treatment with rosiglitazone. Here we report the crystal structure of the PPAR{gamma} ligand-binding domain bound to rosiglitazone and to a large PGC-1{alpha} fragment that contains two LXXLL-related motifs. The structure reveals critical contacts mediated through the first LXXLL motif of PGC-1{alpha} and the PPAR{gamma} coactivator binding site. Through a combination of biochemical and structural studies, we demonstrate that the first LXXLL motif is the most potent among all nuclear receptor coactivator motifs tested, and only this motif of the two LXXLL-related motifs in PGC-1{alpha} is capable of binding to PPAR{gamma}. Our studies reveal that the strong interaction of PGC-1{alpha} and PPAR{gamma} is mediated through both hydrophobic and specific polar interactions. Mutations within the context of the full-length PGC-1{alpha} indicate that the first PGC-1{alpha} motif is necessary and sufficient for PGC-1{alpha} to coactivate PPAR{gamma} in the presence or absence of rosiglitazone. These results provide a molecular basis for specific recruitment and functional interplay between PPAR{gamma} and PGC-1{alpha} in glucose homeostasis and adipocyte differentiation.

  14. Biochemical composition and antioxidant activities of Arthrospira (Spirulina) platensis in response to gamma irradiation.

    PubMed

    Shabana, Effat Fahmy; Gabr, Mahmoud Ali; Moussa, Helal Ragab; El-Shaer, Enas Ali; Ismaiel, Mostafa M S

    2017-01-01

    Arthrospira (Spirulina) platensis is a blue-green alga, rich with bioactive components and nutrients. To evaluate effect of gamma irradiation, A. platensis was exposed to different doses of 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5kGy. The data showed that the phenolic and proline contents significantly increased with the increase of gamma irradiation doses up to 2.0kGy, above which a reduction was observed. The soluble proteins and malondialdehyde (MDA) contents were stimulated by all tested irradiation doses. Furthermore, the vitamins (A, K and B group) and mineral contents (N, P, Na, K, Ca, Mg and Fe) were stimulated by the irradiation doses compared with the control. The activities of some N-assimilating and antioxidant enzymes were significantly increased with the irradiation doses up to 2.0kGy. This study suggests the possible use of gamma irradiation as a stimulatory agent to raise the nutritive value and antioxidant activity of A. platensis. PMID:27507509

  15. Prompt gamma neutron activation analysis of toxic elements in radioactive waste packages.

    PubMed

    Ma, J-L; Carasco, C; Perot, B; Mauerhofer, E; Kettler, J; Havenith, A

    2012-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R&D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages. In particular, the amount of toxic elements present in radioactive waste packages must be assessed before they can be accepted in repository facilities in order to avoid pollution of underground water reserves. To this aim, the Nuclear Measurement Laboratory of CEA-Cadarache has started to study the performances of Prompt Gamma Neutron Activation Analysis (PGNAA) for elements showing large capture cross sections such as mercury, cadmium, boron, and chromium. This paper reports a comparison between Monte Carlo calculations performed with the MCNPX computer code using the ENDF/B-VII.0 library and experimental gamma rays measured in the REGAIN PGNAA cell with small samples of nickel, lead, cadmium, arsenic, antimony, chromium, magnesium, zinc, boron, and lithium to verify the validity of a numerical model and gamma-ray production data. The measurement of a ∼20kg test sample of concrete containing toxic elements has also been performed, in collaboration with Forschungszentrum Jülich, to validate the model in view of future performance studies for dense and large LL-MA waste packages. PMID:22406218

  16. Relativistic particles and gamma-rays in quasars and active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Protheroe, R. J.; Kazanas, D.

    1983-01-01

    A model for a class of quasars and active galactic nuclei is described in which a shock around a massive black hole randomizes the infall kinetic energy of spherically accreting matter producing a nonthermal spectrum of high energy protons. These protons may be responsible for the secondary production (via tau + or - decay) of the radio emitting high energy electrons and also of high energy gamma rays (via Pi decay and inverse Compton interactions of the electrons). The correlation between radio and gamma ray emission implied by the model is in good agreement with observations of 3C273. Observation of the flux of high energy neutrinos from quasars may provide a test for the model.

  17. Relativistic particles and gamma-ray in quasars and active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Protheroe, R. J.; Kazanas, D.

    1982-01-01

    A model for a class of quasars and active galactic nuclei is described in which a shock around a massive black hole randomizes the infall kinetic energy of spherically accreting matter producing a nonthermal spectrum of high energy protons. These protons may be responsible for the secondary production (via tau + or - decay) of the radio emitting high energy electrons and also of high energy gamma rays (via pi decay and inverse Compton interactions of the electrons). The correlation between radio and gamma ray emission implied by the model is in good agreement with observations of 3C273. Observation of the flux of high energy neutrinos from quasars may provide a test for the model.

  18. Determination of boron in materials by cold neutron prompt gamma-ray activation analysis.

    PubMed

    Paul, Rick L

    2005-01-01

    An instrument for cold neutron prompt gamma-ray activation analysis (PGAA), located at the NIST Center for Neutron Research (NCNR), has proven useful for the measurement of boron in a variety of materials. Neutrons, moderated by passage through liquid hydrogen at 20 K, pass through a (58)Ni coated guide to the PGAA station in the cold neutron guide hall of the NCNR. The thermal equivalent neutron fluence rate at the sample position is 9 x 10(8) cm(-2) s(-1). Prompt gamma rays are measured by a cadmium- and lead-shielded high-purity germanium detector. The instrument has been used to measure boron mass fractions in minerals, in NIST SRM 2175 (Refractory Alloy MP-35-N) for certification of boron, and most recently in semiconductor-grade silicon. The limit of detection for boron in many materials is <10 ng g(-1). PMID:15614360

  19. Stabilization of prompt gamma-ray neutron activation analysis (PGNAA) spectra from NaI detectors

    NASA Astrophysics Data System (ADS)

    Metwally, W. A.; Gardner, R. P.

    2004-06-01

    NaI detectors are still used frequently in industrial Prompt Gamma-Ray Neutron Activation Analysis applications such as in bulk material analysis. They have the advantages of being efficient for high-energy gamma rays, being relatively rugged, and being able to be used without cooling. When using NaI detectors, and consequently photomultiplier tubes, the quality of the data can drastically deteriorate through gain and zero shifts that result in spectral smearing due to temperature and/or counting rate changes. A new offline approach is presented to stabilize the NaI spectral drift. The approach is not sensitive to the cause of the drift and takes into account the NaI and ADC non-linearities. Peak resolution is improved substantially when this approach is used in the presence of spectral drift.

  20. A synthetic antagonist for the peroxisome proliferator-activated receptor gamma inhibits adipocyte differentiation.

    PubMed

    Wright, H M; Clish, C B; Mikami, T; Hauser, S; Yanagi, K; Hiramatsu, R; Serhan, C N; Spiegelman, B M

    2000-01-21

    While searching for natural ligands for the peroxisome proliferator-activated receptor (PPAR) gamma, we identified a synthetic compound that binds to this receptor. Bisphenol A diglycidyl ether (BADGE) is a ligand for PPARgamma with a K(d(app)) of 100 microM. This compound has no apparent ability to activate the transcriptional activity of PPARgamma; however, BADGE can antagonize the ability of agonist ligands such as rosiglitazone to activate the transcriptional and adipogenic action of this receptor. BADGE also specifically blocks the ability of natural adipogenic cell lines such as 3T3-L1 and 3T3-F442A cells to undergo hormone-mediated cell differentiation. These results provide the first pharmacological evidence that PPARgamma activity is required for the hormonally induced differentiation of adipogenic cells. PMID:10636887

  1. Peroxisome proliferator-activated receptor {gamma} is expressed in hippocampal neurons and its activation prevents {beta}-amyloid neurodegeneration: role of Wnt signaling

    SciTech Connect

    Inestrosa, Nibaldo C. . E-mail: ninestr@genes.bio.puc.cl; Godoy, Juan A.; Quintanilla, Rodrigo A.; Koenig, Cecilia S.; Bronfman, Miguel

    2005-03-10

    The molecular pathogenesis of Alzheimer's disease (AD) involves the participation of the amyloid-{beta}-peptide (A{beta}), which plays a critical role in the neurodegeneration that triggers the disease. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors, which are members of the nuclear receptor family. We report here that (1) PPAR{gamma} is present in rat hippocampal neurons in culture. (2) Activation of PPAR{gamma} by troglitazone and rosiglitazone protects rat hippocampal neurons against A{beta}-induced neurodegeneration, as shown by the 3-[4,5 -2yl]-2,5-diphenyltetrazolium bromide (MTT) reduction assay, immunofluorescence using an anti-heavy neurofilament antibody, and quantitative electron microscopy. (3) Hippocampal neurons treated with several PPAR{gamma} agonists, including troglitazone, rosiglitazone, and ciglitazone, prevent the excitotoxic A{beta}-induced rise in bulk-free Ca{sup 2+}. (4) PPAR{gamma} activation results in the modulation of Wnt signaling components, including the inhibition of glycogen synthase kinase-3{beta} (GSK-3{beta}) and an increase of the cytoplasmic and nuclear {beta}-catenin levels. We conclude that the activation of PPAR{gamma} prevents A{beta}-induced neurodegeneration by a mechanism that may involve a cross talk between neuronal PPAR{gamma} and the Wnt signaling pathway. More important, the fact that the activation of PPAR{gamma} attenuated A{beta}-dependent neurodegeneration opens the possibility to fight AD from a new therapeutic perspective.

  2. Activation of mutant protein kinase C{gamma} leads to aberrant sequestration and impairment of its cellular function

    SciTech Connect

    Doran, Graeme; Davies, Kay E.; Talbot, Kevin

    2008-08-01

    Mutations in protein kinase C{gamma} (PKC{gamma}) cause the neurodegenerative disease spinocerebellar ataxia type 14 (SCA14). In this study, expression of an extensive panel of known SCA14-associated PKC{gamma} mutations as fusion proteins in cell culture led to the consistent formation of cytoplasmic aggregates in response to purinoceptor stimulation. Aggregates co-stained with antibodies to phosphorylated PKC{gamma} and the early endosome marker EEA1 but failed to redistribute to the cell membrane under conditions of oxidative stress. These studies suggest that Purkinje cell damage in SCA14 may result from a reduction of PKC{gamma} activity due its aberrant sequestration in the early endosome compartment.

  3. Search for gamma-ray-emitting active galactic nuclei in the Fermi-LAT unassociated sample using machine learning

    SciTech Connect

    Doert, M.; Errando, M. E-mail: errando@astro.columbia.edu

    2014-02-10

    The second Fermi-LAT source catalog (2FGL) is the deepest all-sky survey available in the gamma-ray band. It contains 1873 sources, of which 576 remain unassociated. Machine-learning algorithms can be trained on the gamma-ray properties of known active galactic nuclei (AGNs) to find objects with AGN-like properties in the unassociated sample. This analysis finds 231 high-confidence AGN candidates, with increased robustness provided by intersecting two complementary algorithms. A method to estimate the performance of the classification algorithm is also presented, that takes into account the differences between associated and unassociated gamma-ray sources. Follow-up observations targeting AGN candidates, or studies of multiwavelength archival data, will reduce the number of unassociated gamma-ray sources and contribute to a more complete characterization of the population of gamma-ray emitting AGNs.

  4. In vitro activation of a transcription factor by gamma interferon requires a membrane-associated tyrosine kinase and is mimicked by vanadate.

    PubMed Central

    Igarashi, K; David, M; Larner, A C; Finbloom, D S

    1993-01-01

    Gamma interferon (IFN-gamma) activates the formation of a DNA-binding protein complex (FcRF gamma) that recognizes the gamma response region (GRR) of the promoter for the human high-affinity Fc gamma receptor. In a membrane-enriched fraction prepared from human peripheral blood monocytes, IFN-gamma activation of FcRF gamma occurred within 1 min and was ATP dependent. Activation of FcRF gamma required a tyrosine kinase activity, and recognition of the GRR sequence by FcRF gamma could be abrogated by treatment with a tyrosine-specific protein phosphatase. Treatment of cells with vanadate alone resulted in the formation of FcRF gamma without the need for IFN-gamma. UV cross-linking and antibody competition experiments demonstrated that the FcRF gamma complex was composed of at least two components: the 91-kDa protein of the IFN-alpha-induced transcription complex ISGF3 and a 43-kDa component that bound directly to the GRR. Therefore, specificity for IFN-induced transcriptional activation of early response genes requires at least two events: (i) ligand-induced activation of membrane-associated protein by tyrosine phosphorylation and (ii) formation of a complex composed of an activated membrane protein(s) and a sequence-specific DNA-binding component. Images PMID:8321205

  5. Spectral evolution of active galactic nuclei: A unified description of the X-ray and gamma

    NASA Technical Reports Server (NTRS)

    Leiter, D.; Boldt, E.

    1982-01-01

    A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually emerge from an earlier stage at z approx = 4 in which they are the thermal X-ray sources responsible for most of the cosmic X-ray background (CXB). The conjecture is pursued that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx. 10 to the 8th power years these central black holes are spun-up to a canonical Kerr equilibrium state (A/M = 0.998; Thorne 1974) and shown how they then can lead to spectral evolution involving non-thermal emission extending to gamma rays, at the expense of reduced thermal disk radiation. That major portion of the CXB remaining after the contribution of usual AGN are considered, while a superposition of AGN sources at z 1 can account for the gamma ray background. Extensive X-ray measurements carried out with the HEAO 1 and 2 missions as well as gamma ray and optical data are shown to compare favorably with principal features of this model.

  6. Transcriptional regulation of the presenilin-1 gene controls gamma-secretase activity.

    PubMed

    Lee, Sebum; Das, Hriday K

    2010-01-01

    Inhibition of basal JNK activity by JNK inhibitor SP600125 or JNK1siRNA repressed presenilin-1 (PS1) expression in SK-N-SH cells by augmenting the level of p53, a repressor of the PS1 gene (1). We now showed that repression of PS1 transcription by JNK inhibitor SP600125 inhibited gamma-secretase mediated processing of amyloid precursor protein (APP) resulting in the accumulation of C99 fragment and the reduction of secreted Abeta40 level without altering the expression of nicastrin (NCT). Co-treatment of cells with SP600125 and p53 inhibitor, pifithrin-alpha, partially nullified the suppressive effects of SP610025 on PS1 expression and secreted Abeta40 level. Suppression of JNK1 by JNK1siRNA also decreased Abeta40 level. Furthermore, overexpression of the repressors p53, ZNF237 and CHD3 of the PS1 gene also suppressed the processing of APP through repression of PS1 transcription by deacetylation of histone at the PS1 promoter. Transcriptional activator Ets2 increased PS1 protein and secreted Abeta40 levels without affecting the expression of NCT by activating PS1 transcription via hyper-acetylation of histone at the PS1 promoter. Therefore, regulation of PS1 transcription modulates gamma-secretase activity. PMID:20036849

  7. GABAB receptor-mediated activation of astrocytes by gamma-hydroxybutyric acid

    PubMed Central

    Gould, Timothy; Chen, Lixin; Emri, Zsuzsa; Pirttimaki, Tiina; Errington, Adam C.; Crunelli, Vincenzo; Parri, H. Rheinallt

    2014-01-01

    The gamma-aminobutyric acid (GABA) metabolite gamma-hydroxybutyric acid (GHB) shows a variety of behavioural effects when administered to animals and humans, including reward/addiction properties and absence seizures. At the cellular level, these actions of GHB are mediated by activation of neuronal GABAB receptors (GABABRs) where it acts as a weak agonist. Because astrocytes respond to endogenous and exogenously applied GABA by activation of both GABAA and GABABRs, here we investigated the action of GHB on astrocytes on the ventral tegmental area (VTA) and the ventrobasal (VB) thalamic nucleus, two brain areas involved in the reward and proepileptic action of GHB, respectively, and compared it with that of the potent GABABR agonist baclofen. We found that GHB and baclofen elicited dose-dependent (ED50: 1.6 mM and 1.3 µM, respectively) transient increases in intracellular Ca2+ in VTA and VB astrocytes of young mice and rats, which were accounted for by activation of their GABABRs and mediated by Ca2+ release from intracellular store release. In contrast, prolonged GHB and baclofen exposure caused a reduction in spontaneous astrocyte activity and glutamate release from VTA astrocytes. These findings have key (patho)physiological implications for our understanding of the addictive and proepileptic actions of GHB. PMID:25225100

  8. Isohumulones, bitter acids derived from hops, activate both peroxisome proliferator-activated receptor alpha and gamma and reduce insulin resistance.

    PubMed

    Yajima, Hiroaki; Ikeshima, Emiko; Shiraki, Maho; Kanaya, Tomoka; Fujiwara, Daisuke; Odai, Hideharu; Tsuboyama-Kasaoka, Nobuyo; Ezaki, Osamu; Oikawa, Shinichi; Kondo, Keiji

    2004-08-01

    The peroxisome proliferator-activated receptors (PPARs) are dietary lipid sensors that regulate fatty acid and carbohydrate metabolism. The hypolipidemic effects of fibrate drugs and the therapeutic benefits of the thiazolidinedione drugs are due to their activation of PPARalpha and -gamma, respectively. In this study, isohumulones, the bitter compounds derived from hops that are present in beer, were found to activate PPARalpha and -gamma in transient co-transfection studies. Among the three major isohumulone homologs, isohumulone and isocohumulone were found to activate PPARalpha and -gamma. Diabetic KK-Ay mice that were treated with isohumulones (isohumulone and isocohumulone) showed reduced plasma glucose, triglyceride, and free fatty acid levels (65.3, 62.6, and 73.1%, respectively, for isohumulone); similar reductions were found following treatment with the thiazolidinedione drug, pioglitazone. Isohumulone treatment did not result in significant body weight gain, although pioglitazone treatment did increase body weight (10.6% increase versus control group). C57BL/6N mice fed a high fat diet that were treated with isohumulones showed improved glucose tolerance and reduced insulin resistance. Furthermore, these animals showed increased liver fatty acid oxidation and a decrease in size and an increase in apoptosis of their hypertrophic adipocytes. A double-blind, placebo-controlled pilot study for studying the effect of isohumulones on diabetes suggested that isohumulones significantly decreased blood glucose and hemoglobin A1c levels after 8 weeks (by 10.1 and 6.4%, respectively, versus week 0). These results suggest that isohumulones can improve insulin sensitivity in high fat diet-fed mice with insulin resistance and in patients with type 2 diabetes. PMID:15178687

  9. In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

    SciTech Connect

    Munive, Marco; Revilla, Angel; Solis, Jose L.

    2007-10-26

    A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO{sub 3} was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl{sub 2}Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm.

  10. Functions of Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) in Gynecologic Disorders

    PubMed Central

    Ren, Ping; Zhang, Yuquan; Huang, Yan; Yang, Yingli; Jiang, Ming

    2015-01-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of a class of nuclear hormone receptors intimately involved in the regulation of expression of myriad genes that regulate energy metabolism, cell differentiation, apoptosis, and inflammation. Although originally discovered as a pivotal regulator of adipocyte differentiation, the roles that PPARγ plays in gynecological disorders are still unknown. There are a number of studies on the functions of PPARγ and its agonists in gynecological disorders. In this mini-review, we provide a brief summary of the advances in recent years. PMID:25987855

  11. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    SciTech Connect

    Williams, R.E.

    1981-10-12

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

  12. Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

    NASA Astrophysics Data System (ADS)

    Van Phu, Dang; Quoc, Le Anh; Duy, Nguyen Ngoc; Lan, Nguyen Thi Kim; Du, Bui Duy; Luan, Le Quang; Hien, Nguyen Quoc

    2014-04-01

    Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli ( E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

  13. Radiation does from medical in-vivo prompt gamma-ray activation using a mobile nuclear reactor.

    PubMed

    Chung, C; Chen, C P; Chang, P S

    1988-10-01

    A method of medical diagnosis of toxic elements, using a neutron beam from a mobile nuclear reactor to perform partial-body in-vivo prompt gamma-ray activation technique, has been developed. Both neutron and gamma-ray dose equivalents in an irradiated phantom and around medical researchers were measured and evaluated. Neutron flux at various kinetic energies was measured using an activation foil technique, and the neutron dose equivalents at tissues of risk inside the irradiated phantom were calculated by neutron transport code. Gamma-ray dose equivalents inside the irradiated phantom and around the nuclear reactor were measured by thermoluminescent dosimeters. The risk associated with the neutron and gamma radiation dose equivalents received by both the irradiated phantom and medical researchers were evaluated in detail. The radiation safety of the in-vivo medical diagnosis using the mobile nuclear reactor, under the context of radiation protection guidelines, is discussed. PMID:3170218

  14. Production of interferon-gamma by in vivo tumor-sensitized T cells: Association with active antitumor immunity

    SciTech Connect

    Bursuker, I.; Pearce, M.T. )

    1990-02-01

    The state of active immunity to Meth A fibrosarcoma in mice immunized with an admixture of Meth A cells and Propionibacterium acnes is associated with possession by the host of spleen cells capable of producing interferon-gamma (IFN-gamma) upon in vitro restimulation with irradiated tumor cells. The ability of spleen cells from immunized mice to produce IFN-gamma in response to irradiated Meth A cells decays as active antitumor immunity is replaced by a state of immunological memory. The IFN-producing cells are L3T4+Ly2+, cyclophosphamide-sensitive and radiosensitive T cells, as determined by their sensitivity to corresponding monoclonal antibodies and complement. The induction of IFN-gamma production by in vivo tumor-sensitized T cells is tumor specific, in that spleen cells from mice immunized against Meth A fibrosarcoma can produce IFN in response to irradiated Meth A cells but not in response to another syngeneic tumor M109 lung carcinoma.

  15. Measured Activities of Al and Ni in gamma-(Ni) and gamma'-(Ni)3Al in the Ni-Al-Pt System

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2007-01-01

    Adding Pt to Ni-Al coatings is critical to achieving the required oxidation protection of Ni-based superalloys, but the nature of the Pt effect remains unresolved. This research provides a fundamental part of the answer by measuring the influence of Pt on the activities of Al and Ni in gamma-(Ni), gamma prime-(Ni)3Al and liquid in the Ni-Al-Pt system. Measurements have been made at 25 compositions in the Ni-rich corner over the temperature range, T = 1400-1750 K, by the vapor pressure technique with a multiple effusion-cell mass spectrometer (multi-cell KEMS). These measurements clearly show adding Pt (for X(sub Pt) less than 0.25) decreases a(Al) while increasing a(Ni). This solution behavior supports the idea that Pt increases Al transport to an alloy / Al2O3 interface and also limits the interaction between the coating and substrate alloys in the gamma-(Ni) + gamma prime-(Ni)3Al region. This presentation will review the progress of this study.

  16. Gamma irradiation induced disintegration of waste activated sludge for biological hydrogen production

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-04-01

    In this paper, gamma irradiation was applied for the disintegration and dissolution of waste activated sludge produced during the biological wastewater treatment, and the solubilized sludge was used as substrate for bio-hydrogen production. The experimental results showed that the solubilization of waste activated sludge was 53.7% at 20 kGy and pH=12, and the SCOD, polysaccharides, protein, TN and TP contents in the irradiated sludge solutions was 3789.6 mg/L, 268.3 mg/L, 1881.5 mg/L, 132.3 mg/L and 80.4 mg/L, respectively. The irradiated sludge was used for fermentative hydrogen production, and the hydrogen yield was 10.5±0.7 mL/g SCODconsumed. It can be concluded that the irradiated waste activated sludge could be used as a low-cost substrate for fermentative hydrogen production.

  17. Determination of hydrogen in metals, semiconductors, and other materials by cold neutron prompt gamma-ray activation analysis

    SciTech Connect

    Paul, R.L.; Lindstrom, R.M.

    1998-12-31

    Cold neutron prompt gamma-ray activation analysis has proven useful for nondestructive measurement of trace hydrogen. The sample is irradiated in a beam of neutrons; the presence of hydrogen is confirmed by the emission of a 2223 keV gamma-ray. Detection limits for hydrogen are 3 mg/kg in quartz and 8 mg/kg in titanium. The authors have used the technique to measure hydrogen in titanium alloys, germanium, quartz, fullerenes and their derivatives, and other materials.

  18. Calcium ionophore and phorbol ester activation of proliferation and. gamma. -IFN production by neonatal mononuclear cells (MNCs)

    SciTech Connect

    Bryson, Y.J.; Kuhls, T.L.; Pineda, E.

    1986-03-01

    Human neonatal MNCs have a dissociation between prolif. and ..gamma..-IFN prod. Although cord MNCs display normal-high prolif. following lectin stim., ..gamma..-IFN prod. is greatly diminished compared to adult MNCs. Increasing data support a 2-stimuli requirement for human T-cell activation as noted in the T-cell line Jurkat as well as in peripheral T-cells. They have compared prolif. and ..gamma..-IFN responses of cord and adult MNCs to the calcium ionophore A23187, phorbol myristate acetate (PMA), PHA and their combinations. Cord and adult MNCs had similar prolif. responses to A23187, PMA and PHA. PMA alone acted as a weak mitogen compared to PHA. Optimal A23187 alone caused very low amts of prolif. Either PMA or A23187 suppressed PHA-stim. prolif. while A23187 augmented PMA-induced prolif. A23187, PMA or PHA alone prod. ..gamma..-IFN in adult but not cord MNCs. The addition of PMA or A23187 augmented the PHA-induced ..gamma..-IFN prod. in both cord and adult MNCs (6..-->..80 IU vs 240..-->..480 IU resp). When combined, A23187 and PMA stim. optimal and comparable amts of ..gamma..-IFN in adult and cord MNCs (480 IU). From these findings they conclude that although the stimuli for ..gamma..-IFN and prolif. may be similar, there is an absolute requirement for 2 stimuli (PMA/A23187) for ..gamma..-IFN prod. by cord cells and optimal prod. in adult MNCs. The defect of ..gamma..-IFN prod. observed in PHA stim. neonatal MNCs can be corrected using a calcium ionophore and protein kinase C activator.

  19. Multiscale Aspects of Generation of High-Gamma Activity during Seizures in Human Neocortex123

    PubMed Central

    Marcuccilli, Charles J.; Ben-Mabrouk, Faiza; Lew, Sean M.; Goodman, Robert R.; McKhann, Guy M.; Frim, David M.; Kohrman, Michael H.; Schevon, Catherine A.; van Drongelen, Wim

    2016-01-01

    High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. However, the effects of the spatiotemporal dynamics of seizure on HG power generation are not well understood. Here, we studied HG generation and propagation, using a three-step, multiscale signal analysis and modeling approach. First, we analyzed concurrent neuronal and microscopic network HG activity in neocortical slices from seven intractable epilepsy patients. We found HG activity in these networks, especially when neurons displayed paroxysmal depolarization shifts and network activity was highly synchronized. Second, we examined HG activity acquired with microelectrode arrays recorded during human seizures (n = 8). We confirmed the presence of synchronized HG power across microelectrode records and the macroscale, both specifically associated with the core region of the seizure. Third, we used volume conduction-based modeling to relate HG activity and network synchrony at different network scales. We showed that local HG oscillations require high levels of synchrony to cross scales, and that this requirement is met at the microscopic scale, but not within macroscopic networks. Instead, we present evidence that HG power at the macroscale may result from harmonics of ongoing seizure activity. Ictal HG power marks the seizure core, but the generating mechanism can differ across spatial scales. PMID:27257623

  20. Activator protein-2gamma (AP-2gamma) expression is specifically induced by oestrogens through binding of the oestrogen receptor to a canonical element within the 5'-untranslated region.

    PubMed Central

    Orso, Francesca; Cottone, Erika; Hasleton, Mark D; Ibbitt, J Claire; Sismondi, Piero; Hurst, Helen C; De Bortoli, Michele

    2004-01-01

    The activator protein 2 (AP-2) transcription factors are essential proteins for oestrogenic repression of the ERBB2 proto-oncogene in breast cancer cells. In the present study, we have examined the possible oestrogenic regulation of AP-2 genes themselves in breast-tumour-derived lines. As early as 1 h after oestrogen treatment, AP-2gamma mRNA was markedly increased, whereas AP-2alpha was down-regulated, but with slower kinetics, and AP-2beta was not affected at all. Addition of anti-oestrogens ablated these effects. Modulation of the protein levels corresponded to changes in the transcript levels, thus suggesting that in oestrogen-treated cells, an inversion of the balance between AP-2alpha and AP-2gamma isoforms occurs. The 5'-untranslated region (5'-UTR) of the human AP-2gamma gene contains one consensus and one degenerate oestrogen-responsive element (ERE). Reporter constructs carrying the AP-2gamma promoter and the 5'-UTR were up-regulated by oestrogens in transient transfection assays. Deletion of the most conserved (but not of the degenerate) ERE from reporter constructs abrogated the oestrogenic response, although both ERE-containing segments were footprinted in DNaseI protection assays. In vitro binding assays demonstrated the ability of oestrogen receptor alpha (ERalpha) to bind to this site, and chromatin immunoprecipitation analysis of the endogenous gene showed that ERalpha occupies this region in response to oestrogens. We conclude that AP-2gamma is a primary oestrogen-responsive gene and suggest that AP-2 proteins may mediate some oestrogenic responses. PMID:14565844

  1. Estrogen-related receptor gamma is a key regulator of muscle mitochondrial activity and oxidative capacity.

    PubMed

    Rangwala, Shamina M; Wang, Xiaomei; Calvo, Jennifer A; Lindsley, Loren; Zhang, Yunyu; Deyneko, Galina; Beaulieu, Valerie; Gao, Jiaping; Turner, Gordon; Markovits, Judit

    2010-07-16

    Estrogen-related receptor gamma (ERRgamma) regulates the perinatal switch to oxidative metabolism in the myocardium. We wanted to understand the significance of induction of ERRgamma expression in skeletal muscle by exercise. Muscle-specific VP16ERRgamma transgenic mice demonstrated an increase in exercise capacity, mitochondrial enzyme activity, and enlarged mitochondria despite lower muscle weights. Furthermore, peak oxidative capacity was higher in the transgenics as compared with control littermates. In contrast, mice lacking one copy of ERRgamma exhibited decreased exercise capacity and muscle mitochondrial function. Interestingly, we observed that increased ERRgamma in muscle generates a gene expression profile that closely overlays that of red oxidative fiber-type muscle. We further demonstrated that a small molecule agonist of ERRbeta/gamma can increase mitochondrial function in mouse myotubes. Our data indicate that ERRgamma plays an important role in causing a shift toward slow twitch muscle type and, concomitantly, a greater capacity for endurance exercise. Thus, the activation of this nuclear receptor provides a potential node for therapeutic intervention for diseases such as obesity, which is associated with reduced oxidative metabolism and a lower type I fiber content in skeletal muscle. PMID:20418374

  2. Memory impairment and alterations in prefrontal cortex gamma band activity following methamphetamine sensitization

    PubMed Central

    Linsenbardt, David N.; Lapish, Christopher C.

    2015-01-01

    Rationale Repeated methamphetamine (MA) use leads to increases in the incentive motivational properties of the drug as well as cognitive impairments. These behavioral alterations persist for some time following abstinence, and neuroadaptations in the structure and function of the prefrontal cortex (PFC) are particularly important for their expression. However, there is a weak understanding of the changes in neural firing and oscillatory activity in the PFC evoked by repeated drug use, thus complicating the development of novel treatment strategies for addiction. Objectives The purpose of the current study was to assess changes in cognitive and brain function following MA sensitization. Methods Sensitization was induced in rats, then temporal and recognition memory were assessed after 1 or 30 days of abstinence. Electrophysiological recordings from the medial PFC were also acquired from rats whereupon simultaneous measures of oscillatory and spiking activity were examined. Results Impaired temporal memory was observed after 1 and 30 days of abstinence. However, recognition memory was only impaired after 1 day of abstinence. An injection of MA profoundly decreased neuronal firing rate and the anesthesia-induced slow oscillation (SO) in both sensitized (SENS) and control (CTRL) rats. Strong correlations were observed between the SO and gamma band power, which was altered in SENS animals. A decrease in the number of neurons phase-locked to the gamma oscillation was also observed in SENS animals. Conclusions The changes observed in PFC function may play an integral role in the expression of the altered behavioral phenotype evoked by MA sensitization. PMID:25572530

  3. Structural basis of the oxidative activation of the carboxysomal [gamma]-carbonic anhydrase, CcmM

    SciTech Connect

    Peña, Kerry L.; Castel, Stephane E.; de Araujo, Charlotte; Espie, George S.; Kimber, Matthew S.

    2010-04-26

    Cyanobacterial RuBisCO is sequestered in large, icosahedral, protein-bounded microcompartments called carboxysomes. Bicarbonate is pumped into the cytosol, diffuses into the carboxysome through small pores in its shell, and is then converted to CO{sub 2} by carbonic anhydrase (CA) prior to fixation. Paradoxically, many {beta}-cyanobacteria, including Thermosynechococcus elongatus BP-1, lack the conventional carboxysomal {beta}-CA, ccaA. The N-terminal domain of the carboxysomal protein CcmM is homologous to {gamma}-CA from Methanosarcina thermophila (Cam) but recombinant CcmM derived from ccaA-containing cyanobacteria show no CA activity. We demonstrate here that either full length CcmM from T. elongatus, or a construct truncated after 209 residues (CcmM209), is active as a CA - the first catalytically active bacterial {gamma}-CA reported. The 2.0 {angstrom} structure of CcmM209 reveals a trimeric, left-handed {beta}-helix structure that closely resembles Cam, except that residues 198-207 form a third {alpha}-helix stabilized by an essential Cys194-Cys200 disulfide bond. Deleting residues 194-209 (CcmM193) results in an inactive protein whose 1.1 {angstrom} structure shows disordering of the N- and C-termini, and reorganization of the trimeric interface and active site. Under reducing conditions, CcmM209 is similarly partially disordered and inactive as a CA. CcmM protein in fresh E. coli cell extracts is inactive, implying that the cellular reducing machinery can reduce and inactivate CcmM, while diamide, a thiol oxidizing agent, activates the enzyme. Thus, like membrane-bound eukaryotic cellular compartments, the {beta}-carboxysome appears to be able to maintain an oxidizing interior by precluding the entry of thioredoxin and other endogenous reducing agents.

  4. Effect of gamma irradiation on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils

    NASA Astrophysics Data System (ADS)

    Zantar, Said; Haouzi, Rachid; Chabbi, Mohamed; Laglaoui, Amin; Mouhib, Mohammed; Mohammed Boujnah; Bakkali, Mohammed; Zerrouk, Mounir Hassani

    2015-10-01

    The effects of gamma irradiation doses (10, 20 and 30 kGy) on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils (EOs) have been studied. The chromatographic analysis showed that the studied EOs were constituted mainly by carvacrol for T. vulgaris and pulegone for M. pulegium. Gamma irradiation on the studied doses, affects quantitatively and not qualitatively some components of the investigated oils. This effect was dose dependent. While the antioxidant activity remains stable at any dose applied for the plants studied, the antimicrobial activity increased in the irradiated samples for gram negative bacteria and did not change for gram+bacteria. This study supports that gamma irradiation employed at sterilizing doses did not compromise the biological activities of medicinal and aromatic plants.

  5. Contralateral parahippocampal gamma-band activity determines noise-like tinnitus laterality: a region of interest analysis.

    PubMed

    Vanneste, S; Heyning, P Van de; Ridder, D De

    2011-12-29

    Tinnitus is described as an auditory perception in the absence of any external sound source. Tinnitus loudness has been correlated to sustained high frequency gamma-band activity in auditory cortex. It remains unknown whether unilateral tinnitus is always generated in the left auditory cortex, irrespective of the side on which the tinnitus is perceived, or in the contralateral auditory cortex. In order to solve this enigma source localized electroencephalographic (EEG) recordings of a homogenous group of unilateral left and right-sided tinnitus patients presenting with noise-like tinnitus was analyzed. Based on a region of interest analysis, the most important result of this study is that tinnitus lateralization depended on the gamma-band activity of the contralateral parahippocampal area. As for the auditory cortex no differences were found between left-sided and right-sided tinnitus patients. However, in comparison to a control group both left and right-sided tinnitus patients had an increased gamma-band activity in both the left and right primary and secondary auditory cortex. Thus whereas in tinnitus the primary and secondary auditory cortices of both sides are characterized by increased gamma-band activity, the side on which the tinnitus is perceived relates to gamma-band activity in the contralateral parahippocampal area. PMID:21920411

  6. Peroxisome proliferator-activated receptor gamma signaling in human sperm physiology

    PubMed Central

    Liu, Li-Li; Xian, Hua; Cao, Jing-Chen; Zhang, Chong; Zhang, Yong-Hui; Chen, Miao-Miao; Qian, Yi; Jiang, Ming

    2015-01-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the PPARs, which are transcription factors of the steroid receptor superfamily. PPARγ acts as an important molecule for regulating energy homeostasis, modulates the hypothalamic-pituitary-gonadal (HPG) axis, and is reciprocally regulated by HPG. In the human, PPARγ protein is highly expressed in ejaculated spermatozoa, implying a possible role of PPARγ signaling in regulating sperm energy dissipation. PPARγ protein is also expressed in Sertoli cells and germ cells (spermatocytes). Its activation can be induced during capacitation and the acrosome reaction. This mini-review will focus on how PPARγ signaling may affect fertility and sperm quality and the potential reversibility of these adverse effects. PMID:25851655

  7. Calibration of the Brookhaven National Laboratory delayed gamma neutron activation facility to measure total body calcium.

    PubMed

    Ma, R; Stamatelatos, I E; Yasumura, S

    2000-05-01

    Differences in body size and shape can cause large variances in the in vivo results of neutron activation analysis. To introduce corrections for body size for the delayed gamma neutron activation facility at Brookhaven National Laboratory, "reference man"-sized and "reference woman"-sized phantoms were constructed. Simulation results using the Monte Carlo Neutron and Photon Transport code also provided correction factors for people of different sizes. For individuals with a body mass index (BMI = weight (kg)/height (m)2) between 20 and 30, no correction was required. At BMIs greater than 30, the effects of neutron attenuation were significant and a correction factor of CF = -0.0192 x BMI + 1.5635 can be applied. PMID:10865727

  8. Activity of Candida rugosa lipase immobilized on gamma-Fe2O3 magnetic nanoparticles.

    PubMed

    Dyal, Ansil; Loos, Katja; Noto, Mayumi; Chang, Seung W; Spagnoli, Chiara; Shafi, Kurikka V P M; Ulman, Abraham; Cowman, Mary; Gross, Richard A

    2003-02-19

    We report the stability and enzymatic activity of Candida rugosa Lipase (E.C.3.1.1.3) immobilized on gamma-Fe2O3 magnetic nanoparticles. The immobilization strategies were either reacting the enzyme amine group with a nanoparticle surface acetyl, or amine groups. In the former, the enzyme was attached through a C=N bond, while in the latter it was connected using glutaraldehyde. AFM images show an average particle size of 20 +/- 10 nm after deconvolution. The enzymatic activity of the immobilized lipase was determined by following the ester cleavage of p-nitrophenol butyrate. The covalently immobilized enzyme was stabile and reactive over 30 days. PMID:12580578

  9. PI3K{gamma} activation by CXCL12 regulates tumor cell adhesion and invasion

    SciTech Connect

    Monterrubio, Maria; Mellado, Mario; Carrera, Ana C.

    2009-10-16

    Tumor dissemination is a complex process, in which certain steps resemble those in leukocyte homing. Specific chemokine/chemokine receptor pairs have important roles in both processes. CXCL12/CXCR4 is the most commonly expressed chemokine/chemokine receptor pair in human cancers, in which it regulates cell adhesion, extravasation, metastatic colonization, angiogenesis, and proliferation. All of these processes require activation of signaling pathways that include G proteins, phosphatidylinositol-3 kinase (PI3K), JAK kinases, Rho GTPases, and focal adhesion-associated proteins. We analyzed these pathways in a human melanoma cell line in response to CXCL12 stimulation, and found that PI3K{gamma} regulates tumor cell adhesion through mechanisms different from those involved in cell invasion. Our data indicate that, following CXCR4 activation after CXCL12 binding, the invasion and adhesion processes are regulated differently by distinct downstream events in these signaling cascades.

  10. Peroxisome proliferator-activated receptor gamma activators affect the maturation of human monocyte-derived dendritic cells.

    PubMed

    Gosset, P; Charbonnier, A S; Delerive, P; Fontaine, J; Staels, B; Pestel, J; Tonnel, A B; Trottein, F

    2001-10-01

    Peroxisome proliferator-activated receptor gamma (PPARgamma ), a member of the nuclear receptor superfamily, has recently been described as a modulator of macrophage functions and as an inhibitor of T cell proliferation. Here, we investigated the role of PPARgamma in dendritic cells (DC), the most potent antigen-presenting cells. We showed that PPARgamma is highly expressed in immature human monocyte-derived DC (MDDC) and that it may affect the immunostimulatory function of MDDC stimulated with lipopolysaccharide (LPS) or via CD40 ligand (CD40L). We found that the synthetic PPARgamma agonist rosiglitazone (as well as pioglitazone and troglitazone) significantly increases on LPS- and CD40L-activated MDDC, the surface expression of CD36 (by 184% and 104%, respectively) and CD86 (by 54% and 48%), whereas it reduces the synthesis of CD80 (by 42% and 42%). Moreover, activation of PPARgamma resulted in a dramatic decreased secretion of the Th1-promoting factor IL-12 in LPS- and CD40L-stimulated cells (by 47% and 62%), while the production of IL-1beta, TNF-alpha, IL-6 and IL-10 was unaffected. Finally, PPARgamma ligands down-modulate the synthesis of IFN-gamma -inducible protein-10 (recently termed as CXCL10) and RANTES (CCL5), both chemokines involved in the recruitment of Th1 lymphocytes (by 49% and 30%), but not the levels of the Th2 cell-attracting chemokines,macrophage-derived chemokine (CCL22) and thymus and activation regulated chemokine (CCL17), in mature MDDC. Taken together, our data suggest that activation of PPARgamma in human DC may have an impact in the orientation of primary and secondary immune responses by favoring type 2 responses. PMID:11592060

  11. The Prompt Gamma Neutron Activation Analysis Facility at ICN-Pitesti

    SciTech Connect

    Barbos, D.; Paunoiu, C.; Mladin, M.; Cosma, C.

    2008-08-14

    PGNAA is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. PGNAA is characterized by its capability for nondestructive multi-elemental analysis and its ability to analyse elements that cannot be determined by INAA. By means of this PGNAA method we are able to increase the performance of INAA method. A facility has been developed at Institute for Nuclear Research-Pitesti so that the unique features of prompt gamma-ray neutron activation analysis can be used to measure trace and major elements in samples. The facility is linked at the radial neutron beam tube at ACPR-TRIGA reactor. During the PGNAA-facility is in use the ACPR reactor will be operated in steady-state mode at 250 KW maximum power. The facility consists of a radial beam-port, external sample position with shielding, and induced prompt gamma-ray counting system.Thermal neutron flux with energy lower than cadmium cut-off at the sample position was measured using thin gold foil is: {phi}{sub scd} = 1.10{sup 6} n/cm{sup 2}/s with a cadmium ratio of:80.The gamma-ray detection system consist of an HpGe detector of 16% efficiency (detector model GC1518) with 1.85 keV resolution capability. The HpGe is mounted with its axis at 90 deg. with respect to the incident neutron beam at distance about 200mm from the sample position. To establish the performance capabilities of the facility, irradiation of pure element or sample compound standards were performed to identify the gama-ray energies from each element and their count rates.

  12. Peroxisome-proliferator-activated receptor-{gamma} agonists inhibit the release of proinflammatory cytokines from RSV-infected epithelial cells

    SciTech Connect

    Arnold, Ralf . E-mail: ralf.arnold@medizin.uni-magdeburg.de; Koenig, Wolfgang

    2006-03-15

    The epithelial cells of the airways are the target cells for respiratory syncytial virus (RSV) infection and the site of the majority of the inflammation associated with the disease. Recently, peroxisome-proliferator-activated receptor {gamma} (PPAR{gamma}), a member of the nuclear hormone receptor superfamily, has been shown to possess anti-inflammatory properties. Therefore, we investigated the role of PPAR{gamma} agonists (15d-PGJ{sub 2}, ciglitazone and troglitazone) on the synthesis of RSV-induced cytokine release from RSV-infected human lung epithelial cells (A549). We observed that all PPAR{gamma} ligands inhibited dose-dependently the release of TNF-{alpha}, GM-CSF, IL-1{alpha}, IL-6 and the chemokines CXCL8 (IL-8) and CCL5 (RANTES) from RSV-infected A549 cells. Concomitantly, the PPAR{gamma} ligands diminished the cellular amount of mRNA encoding for IL-6, CXCL8 and CCL5 and the RSV-induced binding activity of the transcription factors NF-{kappa}B (p65/p50) and AP-1 (c-fos), respectively. Our data presented herein suggest a potential application of PPAR{gamma} ligands in the anti-inflammatory treatment of RSV infection.

  13. Antioxidant activity of gamma-oryzanol: mechanism of action and its effect on oxidative stability of pharmaceutical oils.

    PubMed

    Juliano, Claudia; Cossu, Massimo; Alamanni, Maria Cristina; Piu, Luisella

    2005-08-11

    Gamma-oryzanol, a phytosteryl ferulate mixture extracted from rice bran oil, has a wide spectrum of biological activities; in particular, it has antioxidant properties and is often used in cosmetic formulations as a sunscreen. The first objective of the present investigation was to elucidate the molecular mechanism(s) of the antioxidant activity of gamma-oryzanol by utilising different in vitro model systems, such as scavenging of stable DPPH radical, OH and O2- radicals scavenging, and azocompound AMVN-initiated lipid peroxidation. The effect of gamma-oryzanol on the oxidative stability of vegetable oils of pharmaceutical and cosmetic interest was then evaluated in a oxidation accelerate test and compared with the effect of the well-known antioxidants BHA and BHT. Our results demonstrate that gamma-oryzanol is an organic radical scavenger able to prevent AMVN-triggered lipoperoxidation. Moreover, when added to oils at concentrations ranging between 2.5 and 10 mmol/kg, gamma-oryzanol shows a dose-dependent increase of the induction times; in particular, it improved the oxidative stability of oils very prone to lipoperoxidation because of their high content of polyunsaturated fatty acids. On the ground of our results, we can conclude that gamma-oryzanol may have a potential application for the stabilization of lipidic raw materials. PMID:16005170

  14. Novel time-dependent vascular actions of {delta}{sup 9}-tetrahydrocannabinol mediated by peroxisome proliferator-activated receptor gamma

    SciTech Connect

    O'Sullivan, Saoirse E. . E-mail: Saoirse.o'sullivan@nottingham.ac.uk; Tarling, Elizabeth J.; Bennett, Andrew J.; Kendall, David A.; Randall, Michael D.

    2005-11-25

    Cannabinoids have widespread effects on the cardiovascular system, only some of which are mediated via G-protein-coupled cell surface receptors. The active ingredient of cannabis, {delta}{sup 9}-tetrahydrocannabinol (THC), causes acute vasorelaxation in various arteries. Here we show for the first time that THC also causes slowly developing vasorelaxation through activation of peroxisome proliferator-activated receptors gamma (PPAR{gamma}). In vitro, THC (10 {mu}M) caused time-dependent vasorelaxation of rat isolated arteries. Time-dependent vasorelaxation to THC was similar to that produced by the PPAR{gamma} agonist rosiglitazone and was inhibited by the PPAR{gamma} antagonist GW9662 (1 {mu}M), but not the cannabinoid CB{sub 1} receptor antagonist AM251 (1 {mu}M). Time-dependent vasorelaxation to THC requires an intact endothelium, nitric oxide, production of hydrogen peroxide, and de novo protein synthesis. In transactivation assays in cultured HEK293 cells, THC-activated PPAR{gamma}, transiently expressed in combination with retinoid X receptor {alpha} and a luciferase reporter gene, in a concentration-dependent manner (100 nM-10 {mu}M). In vitro incubation with THC (1 or 10 {mu}M, 8 days) stimulated adipocyte differentiation in cultured 3T3L1 cells, a well-accepted property of PPAR{gamma} ligands. The present results provide strong evidence that THC is a PPAR{gamma} ligand, stimulation of which causes time-dependent vasorelaxation, implying some of the pleiotropic effects of cannabis may be mediated by nuclear receptors.

  15. Activated AMPK inhibits PPAR-{alpha} and PPAR-{gamma} transcriptional activity in hepatoma cells.

    PubMed

    Sozio, Margaret S; Lu, Changyue; Zeng, Yan; Liangpunsakul, Suthat; Crabb, David W

    2011-10-01

    AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-α (PPAR-α) are critical regulators of short-term and long-term fatty acid oxidation, respectively. We examined whether the activities of these molecules were coordinately regulated. H4IIEC3 cells were transfected with PPAR-α and PPAR-γ expression plasmids and a peroxisome-proliferator-response element (PPRE) luciferase reporter plasmid. The cells were treated with PPAR agonists (WY-14,643 and rosiglitazone), AMPK activators 5-aminoimidazole-4-carboxamide riboside (AICAR) and metformin, and the AMPK inhibitor compound C. Both AICAR and metformin decreased basal and WY-14,643-stimulated PPAR-α activity; compound C increased agonist-stimulated reporter activity and partially reversed the effect of the AMPK activators. Similar effects on PPAR-γ were seen, with both AICAR and metformin inhibiting PPRE reporter activity. Compound C increased basal PPAR-γ activity and rosiglitazone-stimulated activity. In contrast, retinoic acid receptor-α (RAR-α), another nuclear receptor that dimerizes with retinoid X receptor (RXR), was largely unaffected by the AMPK activators. Compound C modestly increased AM580 (an RAR agonist)-stimulated activity. The AMPK activators did not affect PPAR-α binding to DNA, and there was no consistent correlation between effects of the AMPK activators and inhibitor on PPAR and the nuclear localization of AMPK-α subunits. Expression of either a constitutively active or dominant negative AMPK-α inhibited basal and WY-14,643-stimulated PPAR-α activity and basal and rosiglitazone-stimulated PPAR-γ activity. We concluded that the AMPK activators AICAR and metformin inhibited transcriptional activities of PPAR-α and PPAR-γ, whereas inhibition of AMPK with compound C activated both PPARs. The effects of AMPK do not appear to be mediated through effects on RXR or on PPAR/RXR binding to DNA. These effects are independent of kinase activity and instead appear to

  16. Comparison of Tuberculin Activity in the Interferon-gamma Assay for the Diagnosis of Bovine Tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle infected with bovine tuberculosis still represent a serious regulatory and health concern in a variety of countries. Early diagnosis using the in vitro interferon gamma (IFN-gamma) assay has been applied for more than a decade. Briefly, IFN-gamma responses in whole blood cultures stimulated w...

  17. Partial proteolysis as a probe of the conformation of the gamma subunit in activated soluble and membrane-bound chloroplast coupling factor 1.

    PubMed

    Schumann, J; Richter, M L; McCarty, R E

    1985-09-25

    Treatments that enhance the latent ATPase activity of the chloroplast coupling factor (CF1) also induce hypersensitivity of the gamma subunit toward trypsin. A number of different gamma subunit cleavage products are formed (Moroney, J. V., and McCarty, R. E. (1982) J. Biol. Chem. 257, 5910-5914). We have compared the gamma cleavage products of membrane-bound and isolated CF1, activated either by reduction of the gamma disulfide bond or by removal of the epsilon subunit. The gamma subunit of isolated CF1 lacking the epsilon subunit was cleaved to a 27,000-Da species. The same cleavage site became exposed following energy-dependent conformational changes in the membrane-bound enzyme. Activation by reduction of the gamma disulfide bond also exposed this site. However, the gamma subunit of reduced CF1 was cleaved rapidly at an additional site and trypsin treatment gave rise to a 25,000-Da gamma species. The small peptide generated by the second cleavage contains one of the cysteinyl residues of the reduced disulfide bridge of gamma. This peptide dissociates from the enzyme and can be isolated by gel filtration. The close proximity of the trypsin cleavage sites to the disulfide bond of gamma is discussed with respect to the effects of tryptic cleavage on the ATPase activity of CF1. The data indicate that structural changes in a limited region of the gamma subunit strongly influence the catalytic properties of both soluble and membrane-bound CF1. PMID:2864336

  18. Visuotactile motion congruence enhances gamma-band activity in visual and somatosensory cortices.

    PubMed

    Krebber, Martin; Harwood, James; Spitzer, Bernhard; Keil, Julian; Senkowski, Daniel

    2015-08-15

    When touching and viewing a moving surface our visual and somatosensory systems receive congruent spatiotemporal input. Behavioral studies have shown that motion congruence facilitates interplay between visual and tactile stimuli, but the neural mechanisms underlying this interplay are not well understood. Neural oscillations play a role in motion processing and multisensory integration. They may also be crucial for visuotactile motion processing. In this electroencephalography study, we applied linear beamforming to examine the impact of visuotactile motion congruence on beta and gamma band activity (GBA) in visual and somatosensory cortices. Visual and tactile inputs comprised of gratings that moved either in the same or different directions. Participants performed a target detection task that was unrelated to motion congruence. While there were no effects in the beta band (13-21Hz), the power of GBA (50-80Hz) in visual and somatosensory cortices was larger for congruent compared with incongruent motion stimuli. This suggests enhanced bottom-up multisensory processing when visual and tactile gratings moved in the same direction. Supporting its behavioral relevance, GBA was correlated with shorter reaction times in the target detection task. We conclude that motion congruence plays an important role for the integrative processing of visuotactile stimuli in sensory cortices, as reflected by oscillatory responses in the gamma band. PMID:26026813

  19. Adsorption of odorous sulfur compounds onto activated carbons modified by gamma irradiation.

    PubMed

    Vega, Esther; Sánchez-Polo, Manuel; Gonzalez-Olmos, Rafael; Martin, María J

    2015-11-01

    A commercial activated carbon (AC) was modified by gamma irradiation and was tested as adsorbent for the removal of ethyl mercaptan, dimethyl disulfide and dimethyl disulfide in wet conditions. Modifications were carried out under five different conditions: irradiation in absence of water, in presence of ultrapure water, in ultrapure water at pH=1.0 and 1000 mg L(-1) Cl(-), in ultrapure water at pH=7.5 and 1000 mg L(-1) Br(-), and in ultrapure water at pH=12.5 and 1000 mg L(-1) NO3(-). The chemical properties of each AC were characterized by elemental analysis, temperature programmed desorption and X-ray photoelectron spectroscopy. Outcomes show that a large number of oxygen functional groups were incorporated in the AC surface by gamma irradiation, especially in the AC irradiated in the presence of ultrapure water. The dynamic adsorption test results reveal that the incorporation of oxygen functional groups did not enhance the adsorption capacities for dimethyl sulfide and dimethyl disulfide. A significant improvement in the ethyl mercaptan adsorption capacity was correlated with the incorporation of phenolic groups in the AC surface. Moreover, diethyl disulfide was detected as by-product of ethyl mercaptan oxidation process under wet conditions and its formation depended on the chemical properties of ACs. PMID:26160734

  20. Clonal expansions of activated gamma/delta T cells in recent-onset multiple sclerosis.

    PubMed Central

    Shimonkevitz, R; Colburn, C; Burnham, J A; Murray, R S; Kotzin, B L

    1993-01-01

    Multiple sclerosis (MS) is a chronic disease characterized by focal demyelination of the white matter of the brain and spinal cord. Central nervous system damage appears to be mediated by infiltrating T lymphocytes and macrophages, and a central role for autoreactive CD4+ T cells has been proposed. However, the initial immune events that lead to the chronic process of MS remain unidentified. We now present evidence that a subset of T lymphocytes bearing gamma/delta T-cell antigen receptors has been activated in patients with recent-onset disease. Cells recovered from the cerebrospinal fluid of subjects with MS were cultured for short periods of time in medium supplemented with T-cell growth factors. Expansions of V delta 1 and V delta 2 T-cell receptor-bearing lymphocytes were found only in cell populations obtained from subjects with recent-onset disease. Similar populations were not expanded in subjects with chronic MS or other neurological diseases. Junctional region sequencing showed the expanded gamma/delta T cells to be oligoclonal in nature, suggestive of specific stimulation by antigen. These results reveal a fundamental difference in the immunopathogenesis of acute vs. chronic disease and provide additional insight into the autoimmune nature of MS. PMID:8430106

  1. OBLIQUE SHOCKS AS THE ORIGIN OF RADIO TO GAMMA-RAY VARIABILITY IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Hughes, Philip A.; Aller, Margo F.; Aller, Hugh D. E-mail: mfa@umich.edu

    2011-07-10

    The 'shock in jet' model for centimeter-waveband blazar variability is revisited, allowing for arbitrary shock orientation with respect to the jet flow direction, and both random and ordered magnetic field. It is shown that oblique shocks can explain events with swings in polarization position angle much less than the 90{sup 0} associated with transverse structures, while retaining the general characteristics of outbursts, including spectral behavior and level of peak percentage polarization. Models dominated by a force-free, minimum energy magnetic field configuration (essentially helical) display a shallow rise in percentage polarization and frequency-dependent swing in polarization position angle not in agreement with the results of single-dish monitoring observations, implying that the field is predominantly random in the quiescent state. Outbursts well explained by the 'shock in jet' model are present during {gamma}-ray flaring in several sources, supporting the idea that shock events are responsible for activity from the radio to {gamma}-ray bands.

  2. Effects of gamma irradiation on physicochemical properties, antioxidant and microbial activities of sour cherry juice

    NASA Astrophysics Data System (ADS)

    Arjeh, Edris; Barzegar, Mohsen; Ali Sahari, Mohammad

    2015-09-01

    Recently, due to the beneficial effects of bioactive compounds, demand for minimally processed fruits and fruit juices has increased rapidly in the world. In this study, sour cherry juice (SCJ) was exposed to gamma irradiation at 0.0, 0.5, 1.5, 3.0, 4.5, and 6.0 kGy and then stored at 4 °C for 60 days. Total soluble solids (TSS), total acidity (TA), color, total phenolic content (TPC), total monomeric anthocyanin content (TMC), antioxidant activity, organic acid profile, and microbial analysis were evaluated at regular intervals during the storage. Results indicated that irradiation did not have any significant effect on TSS, while level of TA increased significantly at the dose of 6 kGy (p<0.05). Furthermore, irradiation treatment and storage time led to a significant increase in L* and b* values and a decrease in a* values. Total monomeric anthocyanin content of the irradiated SCJ was lower than that of the non-irradiated one (24% at 3.0 kGy) and also changed toward a more negative direction during the storage (63% at 3.0 kGy for 60 days). There was a significant decrease in the antioxidant activity (DPPH radical scavenging and FRAP assay) in both irradiated and stored SCJs. After irradiation (0-6 kGy), the results showed that the concentration of malic and oxalic acid significantly increased; but, the concentration of ascorbic, citric, fumaric, and succinic acids significantly decreased. Gamma irradiation with doses of ≥3 kGy resulted in overall reduction in microbial loads. Based on the results obtained from the changes of physicochemical properties, antioxidant activity, and microbial analysis, irradiation of SCJ at doses of higher than 3.0 kGy is not recommended.

  3. Phosphoinositide 3-kinase-gamma induces Xenopus oocyte maturation via lipid kinase activity.

    PubMed Central

    Hehl, S; Stoyanov, B; Oehrl, W; Schönherr, R; Wetzker, R; Heinemann, S H

    2001-01-01

    Type-I phosphoinositide 3-kinases (PI3Ks) were characterized as a group of intracellular signalling proteins expressing both protein and lipid kinase activities. Recent studies implicate PI3Ks as mediators of oocyte maturation, but the molecular mechanisms are poorly defined. Here we used the Xenopus oocyte expression system as a model to investigate a possible contribution of the gamma-isoform of PI3K (PI3Kgamma) in the different pathways leading to cell-cycle progression by monitoring the time course of germinal vesicle breakdown (GVBD). Expression of a constitutive active PI3Kgamma (PI3Kgamma-CAAX) induced GVBD and increased the levels of phosphorylated Akt/protein kinase B and mitogen-activated protein kinase (MAPK). Furthermore, PI3Kgamma-CAAX accelerated progesterone-induced GVBD, but had no effect on GVBD induced by insulin. The effects of PI3Kgamma-CAAX could be suppressed by pre-incubation of the oocytes with LY294002, PD98059 or roscovitine, inhibitors of PI3K, MEK (MAPK/extracellular-signal-regulated protein kinase kinase) and cdc2/cyclin B kinase, respectively. Mutants of PI3Kgamma-CAAX, in which either lipid kinase or both lipid and protein kinase activities were altered or eliminated, did not induce significant GVBD. Our data demonstrate that expression of PI3Kgamma in Xenopus oocytes accelerates their progesterone-induced maturation and that lipid kinase activity is required to induce this effect. PMID:11736661

  4. Characterization of HPGe gamma spectrometric detectors systems for Instrumental Neutron Activation Analysis (INAA) at the Colombian Geological Survey

    NASA Astrophysics Data System (ADS)

    Sierra, O.; Parrado, G.; Cañón, Y.; Porras, A.; Alonso, D.; Herrera, D. C.; Peña, M.; Orozco, J.

    2016-07-01

    This paper presents the progress made by the Neutron Activation Analysis (NAA) laboratory at the Colombian Geological Survey (SGC in its Spanish acronym), towards the characterization of its gamma spectrometric systems for Instrumental Neutron Activation Analysis (INAA), with the aim of introducing corrections to the measurements by variations in sample geometry. Characterization includes the empirical determination of the interaction point of gamma radiation inside the Germanium crystal, through the application of a linear model and the use of a fast Monte Carlo N-Particle (MCNP) software to estimate correction factors for differences in counting efficiency that arise from variations in sample density between samples and standards.

  5. Reversal of evoked gamma oscillation deficits is predictive of antipsychotic activity with a unique profile for clozapine

    PubMed Central

    Hudson, M R; Rind, G; O'Brien, T J; Jones, N C

    2016-01-01

    Recent heuristic models of schizophrenia propose that abnormalities in the gamma frequency cerebral oscillations may be closely tied to the pathophysiology of the disorder, with hypofunction of N-methyl-d-aspartate receptors (NMDAr) implicated as having a crucial role. Prepulse inhibition (PPI) is a behavioural measure of sensorimotor gating that is disrupted in schizophrenia. We tested the ability for antipsychotic drugs with diverse pharmacological actions to (1) ameliorate NMDAr antagonist-induced disruptions to gamma oscillations and (2) attenuate NMDAr antagonist-induced disruptions to PPI. We hypothesized that antipsychotic-mediated improvement of PPI deficits would be accompanied by a normalization of gamma oscillatory activity. Wistar rats were implanted with extradural electrodes to facilitate recording of electroencephalogram during PPI behavioural testing. In each session, the rats were administered haloperidol (0.25 mg kg−1), clozapine (5 mg kg−1), olanzapine (5 mg kg−1), LY379268 (3 mg kg−1), NFPS (sarcosine, 1 mg kg−1), d-serine (1800 mg kg−1) or vehicle, followed by the NMDAr antagonists MK-801(0.16 mg kg−1), ketamine (5 mg kg−1) or vehicle. Outcome measures were auditory-evoked, as well as ongoing, gamma oscillations and PPI. Although treatment with all the clinically validated antipsychotic drugs reduced ongoing gamma oscillations, clozapine was the only compound that prevented the sensory-evoked gamma deficit produced by ketamine and MK-801. In addition, clozapine was also the only antipsychotic that attenuated the disruption to PPI produced by the NMDAr antagonists. We conclude that disruptions to evoked, but not ongoing, gamma oscillations caused by NMDAr antagonists are functionally relevant, and suggest that compounds, which restore sensory-evoked gamma oscillations may improve sensory processing in patients with schizophrenia. PMID:27093066

  6. Reversal of evoked gamma oscillation deficits is predictive of antipsychotic activity with a unique profile for clozapine.

    PubMed

    Hudson, M R; Rind, G; O'Brien, T J; Jones, N C

    2016-01-01

    Recent heuristic models of schizophrenia propose that abnormalities in the gamma frequency cerebral oscillations may be closely tied to the pathophysiology of the disorder, with hypofunction of N-methyl-d-aspartate receptors (NMDAr) implicated as having a crucial role. Prepulse inhibition (PPI) is a behavioural measure of sensorimotor gating that is disrupted in schizophrenia. We tested the ability for antipsychotic drugs with diverse pharmacological actions to (1) ameliorate NMDAr antagonist-induced disruptions to gamma oscillations and (2) attenuate NMDAr antagonist-induced disruptions to PPI. We hypothesized that antipsychotic-mediated improvement of PPI deficits would be accompanied by a normalization of gamma oscillatory activity. Wistar rats were implanted with extradural electrodes to facilitate recording of electroencephalogram during PPI behavioural testing. In each session, the rats were administered haloperidol (0.25 mg kg(-1)), clozapine (5 mg kg(-1)), olanzapine (5 mg kg(-1)), LY379268 (3 mg kg(-1)), NFPS (sarcosine, 1 mg kg(-1)), d-serine (1800 mg kg(-1)) or vehicle, followed by the NMDAr antagonists MK-801(0.16 mg kg(-1)), ketamine (5 mg kg(-1)) or vehicle. Outcome measures were auditory-evoked, as well as ongoing, gamma oscillations and PPI. Although treatment with all the clinically validated antipsychotic drugs reduced ongoing gamma oscillations, clozapine was the only compound that prevented the sensory-evoked gamma deficit produced by ketamine and MK-801. In addition, clozapine was also the only antipsychotic that attenuated the disruption to PPI produced by the NMDAr antagonists. We conclude that disruptions to evoked, but not ongoing, gamma oscillations caused by NMDAr antagonists are functionally relevant, and suggest that compounds, which restore sensory-evoked gamma oscillations may improve sensory processing in patients with schizophrenia. PMID:27093066

  7. Wakayama Symposium: Peroxisome Proliferator-Activated Receptor-gamma (PPARγ) and Meibomian Gland Dysfunction

    PubMed Central

    Jester, James V.; Brown, Donald J.

    2012-01-01

    Recently we have shown that mouse and human meibomian glands undergo specific age-related changes, including decreased acinar cell proliferation, acinar atrophy, and altered peroxisome proliferator-activated receptor gamma (PPARγ) localization from cytoplasmic-vesicular/nuclear in young mice and humans to nuclear in old mice and humans. Since PPARγ is a lipid-sensitive, nuclear receptor implicated in regulating adipocyte and sebocyte differentiation and lipogenesis, our findings suggest that PPARγ may be involved in modulating meibomian gland differentiation during aging. Based on these findings, we propose that aging of the meibomian gland results in downregulation of PPARγ, leading to decreased meibocyte differentiation and lipid synthesis, gland atrophy, and a hyposecretory meibomian gland dysfunction. PMID:23084144

  8. Transcriptional activity of interferon gamma and two subunits of its receptor as molecular markers of myocarditis.

    PubMed

    Smolik, Sławomir; Domal-Kwiatkowska, Dorota; Nowalany-Kozielska, Ewa; Wojnicz, Romuald; Swiatowska, Longina; Ludmiła, Weglarz

    2008-01-01

    Inflammatory cytokines have an important role in the pathogenesis of myocarditis, but still little is known about the importance of interferon gamma (IFNg) in this disease. The aim of the study was to evaluate the prognostic value of the initial transcriptional activity of IFNg and two subunits of its receptor as measured with the use of QRT-PCR and SYBRGreen chemistry in the group of 63 patients with clinically confirmed myocarditis who were treated with statin or immunosupressive therapy. The initial values of IFNg and the ratio of IFNgRb/IFNgRa were statistically different in the analyzed group of patients. The prognostic value of IFNg and IFNgRb/IFNgRa was determined by logistic regression analysis. PMID:19172849

  9. Near Infrared Activity Close to the Crab Pulsar Correlated with Giant Gamma-ray Flares

    NASA Technical Reports Server (NTRS)

    Rudy, Alexander R.; Max, Claire E.; Weisskopf, Martin C.

    2014-01-01

    We describe activity observed in the near-infrared correlated with a giant gamma-ray flare in the Crab Pulsar. The Crab Pulsar has been observed by the Fermi and AGILE satellites to flare for a period of 3 to 7 days, once every 1-1.5 years, increasing in brightness by a factor of 3-10 between 100MeV and 1GeV. We used Keck NIRC2 laser guide star adaptive optics imaging to observe the Crab Pulsar and environs before and during the March 2013 flare. We discuss the evidence for the knot as the location of the flares, and the theoretical implications of these observations. Ongoing target-of-opportunity programs hope to confirm this correlation for future flares.

  10. Carvacrol, a component of thyme oil, activates PPARalpha and gamma and suppresses COX-2 expression.

    PubMed

    Hotta, Mariko; Nakata, Rieko; Katsukawa, Michiko; Hori, Kazuyuki; Takahashi, Saori; Inoue, Hiroyasu

    2010-01-01

    Cyclooxygenase-2 (COX-2), the rate-limiting enzyme in prostaglandin biosynthesis, plays a key role in inflammation and circulatory homeostasis. Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors belonging to the nuclear receptor superfamily and are involved in the control of COX-2 expression, and vice versa. Here, we show that COX-2 promoter activity was suppressed by essential oils derived from thyme, clove, rose, eucalyptus, fennel, and bergamot in cell-based transfection assays using bovine arterial endothelial cells. Moreover, from thyme oil, we identified carvacrol as a major component of the suppressor of COX-2 expression and an activator of PPARalpha and gamma. PPARgamma-dependent suppression of COX-2 promoter activity was observed in response to carvacrol treatment. In human macrophage-like U937 cells, carvacrol suppressed lipopolysaccharide-induced COX-2 mRNA and protein expression, suggesting that carvacrol regulates COX-2 expression through its agonistic effect on PPARgamma. These results may be important in understanding the antiinflammatory and antilifestyle-related disease properties of carvacrol. PMID:19578162

  11. Hint1 knockout results in a compromised activation of protein kinase C gamma in the brain.

    PubMed

    Zhang, Fan; Fang, Zhenfei; Wang, Jia Bei

    2015-10-01

    Previous studies have implicated a role of the histidine triad nucleotide-binding protein 1 (Hint1) in the pathogenesis of schizophrenia. Protein kinase C gamma (PKCγ) could be potentially involved in the Hint1-implicated pathogenesis since PKCγ was identified as a Hint1 interacting protein. Recently, a debate was brought forward from the understanding how Hint1 affects the expression and activity of PKCγ in the brain. In the present study, we use Hint1 knockout mice and biochemical analysis to define the effect of Hint1 on protein PKCγ. Our data reveal that Hint1-deficiency in mouse brains led to increased protein levels of PKCγ in the cortex and hippocampus, the striatum and thalamus and amygdala. Without stimulation, PKCγ protein in Hint1-deficient brain displayed a basal activity that was reflected by control-leveled phosphorylations of PKCγ T514 and T674 at its kinase domain. Upon psycho-stimulation, both sites of PKCγ T514 and T674 were activated in these brain structures via phosphorylation; however, the phosphorylation level at the site of PKCγ T674 apparently attenuated in Hint1-deficient mice compared to wild-type control. Thus, we conclude that Hint1 deficiency leads to an increased protein level of PKCγ in the brain and a compromised activation response of PKCγ upon stimulation. These findings suggest an inhibitory role of Hint1 on the protein PKCγ in the brain and an impaired PKCγ-mediated phosphorylation signal in Hint1-deficient neuron. PMID:26133792

  12. Identification of novel peroxisome proliferator-activated receptor-gamma (PPARγ) agonists using molecular modeling method.

    PubMed

    Gee, Veronica M W; Wong, Fiona S L; Ramachandran, Lalitha; Sethi, Gautam; Kumar, Alan Prem; Yap, Chun Wei

    2014-11-01

    Peroxisome proliferator-activated receptor-gamma (PPARγ) plays a critical role in lipid and glucose homeostasis. It is the target of many drug discovery studies, because of its role in various disease states including diabetes and cancer. Thiazolidinediones, a synthetic class of agents that work by activation of PPARγ, have been used extensively as insulin-sensitizers for the management of type 2 diabetes. In this study, a combination of QSAR and docking methods were utilised to perform virtual screening of more than 25 million compounds in the ZINC library. The QSAR model was developed using 1,517 compounds and it identified 42,378 potential PPARγ agonists from the ZINC library, and 10,000 of these were selected for docking with PPARγ based on their diversity. Several steps were used to refine the docking results, and finally 30 potentially highly active ligands were identified. Four compounds were subsequently tested for their in vitro activity, and one compound was found to have a K i values of <5 μM. PMID:25168706

  13. Effect of. gamma. -irradiated DNA on the activity of DNA polymerase. [/sup 60/Co

    SciTech Connect

    Leadon, S.A.; Ward, J.F.

    1981-06-01

    A cell-free assay was developed to measure the effect of ..gamma..-irradiated DNA template on the ability of DNA polymerase to copy unirradiated template. Doses as low as 1 krad were able to decrease (approx. 15%) the activity of both bacterial and mammalian DNA polymerases in the assay. The percentage of polymerase activity decreased as the dose received by the template increased. The reduction in DNA polymerase activity was shown to be due to an inhibition of the enzyme by the irradiated DNA. Irradiated poly(dA-dT) was more effective in reducing polymerase activity than calf thymus DNA. Thus the polymerase-inhibition site(s) appears to be associated with base damage, specifically adenine or thymine. Using a free-radical scavenger, OH radicals were found to be involved in producing the damage sites. The interaction between irradiated DNA and DNA polymerase was found to be specific for the enzyme and not for other proteins present in the assay. The inhibition of DNA polymerase occurred prior to or during the initiation of DNA synthesis rather than after initiation of synthesis, i.e., during elongation.

  14. Effect of gamma irradiation on the antimicrobial and free radical scavenging activities of Glycyrrhiza glabra root

    NASA Astrophysics Data System (ADS)

    Fatima Khattak, Khanzadi; James Simpson, Thomas

    2010-04-01

    The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25 kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the present study showed that radiation treatment up to 20 kGy does not affect the antifungal and antibacterial activity of the plant. While sample irradiated at 25 kGy does showed changes in the antibacterial activity against some selected pathogens. No significant differences in the phenolic contents were observed for control and samples irradiated at 5, 10 and 15 kGy radiation doses. However, phenolic contents increased in samples treated with 20 and 25 kGy doses. The DPPH scavenging activity significantly ( p<0.05) increased in all irradiated samples of the plant.

  15. Effect of gamma irradiation on the microbial load, nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome

    NASA Astrophysics Data System (ADS)

    Khattak, Khanzadi Fatima; Simpson, Thomas James; Ihasnullah

    2009-03-01

    The assurance of microbial quality is necessary to make plant materials suitable for human consumption and commercialization. The aim of the present study was to evaluate the possibility to apply the gamma radiation treatment on the rhizome samples of Nelumbo nucifera for microbial decontamination. The radiation processing was carried out at dose levels of 1, 2, 4 and 6 kGy. The irradiated and control samples were analyzed for microbial load, organoleptic acceptance, extraction yield, proximate composition, phenolic contents and DPPH scavenging activity. The results indicated that gamma radiation treatment significantly reduced microbial load and increased the storability of the irradiated samples. The treated samples were also acceptable sensorically. The extraction yield and phenolic contents increased with the increase of radiation dose. Gamma radiation also enhanced the DPPH scavenging activity.

  16. Irbesartan increased PPAR{gamma} activity in vivo in white adipose tissue of atherosclerotic mice and improved adipose tissue dysfunction

    SciTech Connect

    Iwai, Masaru; Kanno, Harumi; Senba, Izumi; Nakaoka, Hirotomo; Moritani, Tomozo; Horiuchi, Masatsugu

    2011-03-04

    Research highlights: {yields} Atherosclerotic apolipoprotein E-deficient (ApoEKO) mice were treated with irbesartan. {yields} Irbesartan decreased white adipose tissue weight without affecting body weight. {yields} DNA-binding for PPAR{gamma} was increased in white adipose tissue in vivo by irbesartan. {yields} Irbesartan increased adipocyte number in white adipose tissue. {yields} Irbesatan increased the expression of adiponectin and leptin in white adipose tissue. -- Abstract: The effect of the PPAR{gamma} agonistic action of an AT{sub 1} receptor blocker, irbesartan, on adipose tissue dysfunction was explored using atherosclerotic model mice. Adult male apolipoprotein E-deficient (ApoEKO) mice at 9 weeks of age were treated with a high-cholesterol diet (HCD) with or without irbesartan at a dose of 50 mg/kg/day for 4 weeks. The weight of epididymal and retroperitoneal adipose tissue was decreased by irbesartan without changing food intake or body weight. Treatment with irbesartan increased the expression of PPAR{gamma} in white adipose tissue and the DNA-binding activity of PPAR{gamma} in nuclear extract prepared from adipose tissue. The expression of adiponectin, leptin and insulin receptor was also increased by irbesartan. These results suggest that irbesartan induced activation of PPAR{gamma} and improved adipose tissue dysfunction including insulin resistance.

  17. Long-term exercise increases the DNA binding activity of peroxisome proliferator-activated receptor gamma in rat adipose tissue.

    PubMed

    Petridou, Anatoli; Tsalouhidou, Sofia; Tsalis, George; Schulz, Thorsten; Michna, Horst; Mougios, Vassilis

    2007-08-01

    The aim of the present study was to examine the effect of 8 weeks of voluntary wheel running on the gene expression, at the protein level, of 2 enzymes involved in lipogenesis (fatty acid synthase [FAS] and diacylglycerol acyl transferase 1), 2 proteins involved in lipolysis (hormone-sensitive lipase [HSL] and perilipin), and 3 transcription factors mediating the induction of genes involved in lipid metabolism (the alpha, gamma, and delta members of the peroxisome proliferator-activated receptor, or PPAR, family) in rat liver, gastrocnemius muscle, epididymal fat, and subcutaneous fat. Proteins were measured through Western blot analysis in the tissues of 11 trained and 14 untrained rats. The trained rats had lower FAS in the liver; higher FAS, HSL, and perilipin in epididymal fat; and higher HSL in subcutaneous fat. In addition, the trained rats had higher total protein concentrations in both fat depots. No significant differences in the liver, muscle, or adipose tissue PPAR contents were found between groups. However, the DNA binding activity of PPARgamma, measured through an enzyme immunoassay-based method, was higher in both fat depots of the trained rats. Our findings suggest that long-term wheel running had significant effects on the concentrations of proteins playing key roles in lipogenesis and lipolysis in rat liver and adipose tissue. These effects may be due to PPAR activation rather than induction, rendering the transcriptional regulation of target genes more economical and flexible. The activation of PPARgamma with exercise may mediate its beneficial effect on insulin sensitivity. PMID:17618946

  18. Peroxisome proliferator-activated receptor-gamma ligands inhibit proliferation and induce apoptosis in mantle cell lymphoma.

    PubMed

    Eucker, Jan; Sterz, Jan; Krebbel, Holger; Zavrski, Ivana; Kaiser, Martin; Zang, Chuanbing; Heider, Ulrike; Jakob, Christian; Elstner, Elena; Sezer, Orhan

    2006-08-01

    Peroxisome proliferator-activated receptor-gamma, a nuclear receptor and transcription factor, and its natural and synthetic ligands have become a focus of novel approaches to induction of apoptosis in solid tumors and hematologic malignancies, including malignant B-lineage cells. The effect on mantle cell lymphoma, a subtype with dismal prognosis, has not yet been analyzed. We investigated the effect of 15-deoxy-delta-12,14-prostaglandin J2 (15d-PGJ2), pioglitazone (PGZ) or rosiglitazone (RGZ) on human mantle cell lymphoma cell lines (GRANTA-519, Hbl-2 and JeKo-1). Mantle cell lymphoma cell lines exhibited a high expression of Peroxisome proliferator-activated receptor-gamma protein in Western blot analysis. MTT assays revealed anti-proliferative effects induced by both 15d-PGJ2, the natural activator of Peroxisome proliferator-activated receptor-gamma, and PGZ and RGZ, synthetic Peroxisome proliferator-activated receptor-gamma ligands, in a dose-dependent manner. At a dose of 50 micromol/l, 15d-PGJ2 induced growth inhibition in all cell lines. The anti-proliferative effect of PGZ and RGZ was slightly lower. Induction of apoptosis was indicated by annexin V staining. At a dose of 50 micromol/l, 15d-PGJ2 led to apoptosis in all cell lines (87-99%) after 48 h of incubation. Again, the apoptotic effect with thiazolidinediones was slightly lower at the same dose level. This is the first study evaluating Peroxisome proliferator-activated receptor-gamma expression and its therapeutic implications in human mantle cell lymphoma cells. Thiazolidinediones comprise anti-lymphoma activity in vitro and should be further explored for the treatment of mantle cell lymphoma. PMID:16926626

  19. Antibacterial activity of starch/acrylamide/allyl triphenyl phosphonium bromide copolymers synthesized by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Song, Weiqiang; Guo, Zhengchao; Zhang, Linqi; Zheng, Hongjuan; Zhao, Zhiwei

    2013-10-01

    Starch/acrylamide/allyl triphenyl phosphonium bromide (St/AM/TP) copolymers were synthesized by simultaneous gamma irradiation and characterized by FTIR and 1H NMR techniques, weight measurement and titration method. Moreover, their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. At St/AM/TP 6:8.4:5.6 g, copolymers with higher graft ratio (G) and higher (AM+TP) graft efficiency (EAM+TP) were obtained at 3 and 6 kGy, while cationic degree (CD) and TP graft efficiency (ETP) continuously increased with absorbed dose from 1 to 6 kGy. All of the copolymers were capable of killing >99.75% of 107 CFU/ml S. aureus within 30 mins. Moreover, at 3 kGy, G, EAM+TP and ETP increased with AM/TP from 0:14 to 11.2:2.8 g at St/(AM+TP) 6:14 g, while the optimum CD and antibacterial activity were achieved at AM/TP 7:7 and 8.4:5.6 g. In addition, at 3 kGy, G, EAM+TP and CD increased with St/(AM+TP) from 6:3 to 6:18 g at AM/TP 8.4:5.6 g, while the optimum antibacterial activity was achieved at 6:10 to 6:18 g, and the optimum ETP was achieved at 6:14.

  20. Enhanced Clearance of Pseudomonas aeruginosa by Peroxisome Proliferator-Activated Receptor Gamma.

    PubMed

    Bedi, Brahmchetna; Yuan, Zhihong; Joo, Myungsoo; Zughaier, Susu M; Goldberg, Joanna B; Arbiser, Jack L; Hart, C Michael; Sadikot, Ruxana T

    2016-07-01

    The pathogenic profile of Pseudomonas aeruginosa is related to its ability to secrete a variety of virulence factors. Quorum sensing (QS) is a mechanism wherein small diffusible molecules, specifically acyl-homoserine lactones, are produced by P. aeruginosa to promote virulence. We show here that macrophage clearance of P. aeruginosa (PAO1) is enhanced by activation of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARγ). Macrophages treated with a PPARγ agonist (pioglitazone) showed enhanced phagocytosis and bacterial killing of PAO1. It is known that PAO1 QS molecules are inactivated by PON-2. QS molecules are also known to inhibit activation of PPARγ by competitively binding PPARγ receptors. In accord with this observation, we found that infection of macrophages with PAO1 inhibited expression of PPARγ and PON-2. Mechanistically, we show that PPARγ induces macrophage paraoxonase 2 (PON-2), an enzyme that degrades QS molecules produced by P. aeruginosa Gene silencing studies confirmed that enhanced clearance of PAO1 in macrophages by PPARγ is PON-2 dependent. Further, we show that PPARγ agonists also enhance clearance of P. aeruginosa from lungs of mice infected with PAO1. Together, these data demonstrate that P. aeruginosa impairs the ability of host cells to mount an immune response by inhibiting PPARγ through secretion of QS molecules. These studies define a novel mechanism by which PPARγ contributes to the host immunoprotective effects during bacterial infection and suggest a role for PPARγ immunotherapy for P. aeruginosa infections. PMID:27091928

  1. Gamma activity of stream sediment feldspars as ceramic raw materials and their environmental impact.

    PubMed

    Aboelkhair, Hatem; Ibrahim, Tarek; Saad, Ahmed

    2012-08-01

    In situ gamma spectrometric measurements have been performed to characterise the natural radiation that emitted from the stream sediment feldspars in Wadi El Missikat and Wadi Homret El Gergab, Eastern Desert, Egypt. The measurements of potassium (K, %), equivalent uranium (eU, ppm) and equivalent thorium (eTh, ppm) were converted into specific activities and equivalent dose rate. The average specific activities were 1402 Bq kg(-1) for K, 113 Bq kg(-1) for eU and 108 Bq kg(-1) for eTh in Wadi El Missikat, while they were 1240, 104 and 185 Bq kg(-1) in Wadi Homret El Gergab. The calculated outdoor average effective dose rates was 1.1 mSv y(-1) in wadi El Missikat and 1.3 mSv y(-1) in Wadi Homret El Gergab. The terrestrial-specific activities and effective dose rate levels of the natural radioactivity in the two areas lie within the international recommended limits for occupational feldspar quarry workers. On the other hand, these results indicated that irradiation is higher than the allowable level for members of the public. Therefore, quarrying the feldspar sediments from these locations as ceramic raw materials may yield an undesired impact on the environment, especially through the indoor applications. PMID:22171098

  2. Involvement of protein kinase D in Fc gamma-receptor activation of the NADPH oxidase in neutrophils.

    PubMed Central

    Davidson-Moncada, Jan K; Lopez-Lluch, Guillermo; Segal, Anthony W; Dekker, Lodewijk V

    2002-01-01

    Protein kinases involved in the activation of the NADPH oxidase by Fc gamma receptors in neutrophils were studied. Of three different protein kinase C (PKC) inhibitors, Gö 6976 inhibited the NADPH oxidase completely, whereas bisindolylmaleimide I and Ro 31-8220 caused a 70-80% inhibition. Thus a Gö 6976-sensitive, bisindolylmaleimide I/Ro 31-8220-insensitive component contributes to NADPH oxidase activation induced by Fc gamma receptors. Down-regulation of PKC isotypes resulted in inhibition of Fc gamma-receptor-activated NADPH oxidase, but a down-regulation-insensitive component was still present. This component was sensitive to Gö 6976, but insensitive to Ro 31-8220. It has been shown previously that protein kinase D/PKC-mu (PKD) shows this same pharmacology in vitro. We show that PKD is present in neutrophils and that, in contrast with PKC isotypes, PKD is not down-regulated. Therefore PKD may participate in NADPH oxidase activation. To obtain direct evidence for this we adopted an antisense approach. Antisense PKD inhibited NADPH oxidase induced by Fc gamma-receptor stimulation by 50% and the Ro 31-8220-insensitive component in the activation was inhibited by antisense PKD. In vitro kinase assays showed that PKD is activated by presenting IgG-opsonized particles to neutrophils. Furthermore, PKD localizes to the area of particle intake in the cell and phosphorylates two of the three cytosolic components of the NADPH oxidase, p40(phox) and p47(phox). Taken together, these data indicate that Fc gamma receptors engage PKD in the regulation of the NADPH oxidase. PMID:11903052

  3. COHN analysis: Body composition measurements based on the associated particle imaging and prompt-gamma neutron activation analysis techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The measurement of the body's carbon (C), oxygen (O), hydrogen (H), and nitrogen (N) content can be used to calculate the relative amounts of fat, protein, and water. A system based on prompt-gamma neutron activation analysis (PGNAA), coupled with the associated particle imaging (API) technique, is...

  4. INITIATION/PROMOTION BIOASSAY IN RAT LIVER: USE OF GAMMA GLUTAMYLTRANSPEPTIDASE-POSITIVE FOCI TO INDICATE CARCINOGENIC ACTIVITY

    EPA Science Inventory

    Gamma Glutamyltranspeptidase (GGTase)-positive foci have been used to indicate activity in an initiation/promotion bioassay in rat liver. This rat liver foci bioassay has been proposed for inclusion in tier 2 of a three tier decision tree approach to carcinogenesis testing where ...

  5. Measuring the activity of a {sup 51}Cr neutrino source based on the gamma-radiation spectrum

    SciTech Connect

    Gorbachev, V. V. Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-15

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of {sup 51}Cr is presented.

  6. Increased Event-Related Potentials and Alpha-, Beta-, and Gamma-Activity Associated with Intentional Actions

    PubMed Central

    Karch, Susanne; Loy, Fabian; Krause, Daniela; Schwarz, Sandra; Kiesewetter, Jan; Segmiller, Felix; Chrobok, Agnieszka I.; Keeser, Daniel; Pogarell, Oliver

    2016-01-01

    Objective: Internally guided actions are defined as being purposeful, self-generated and offering choices between alternatives. Intentional actions are essential to reach individual goals. In previous empirical studies, internally guided actions were predominantly related to functional responses in frontal and parietal areas. The aim of the present study was to distinguish event-related potentials and oscillatory responses of intentional actions and externally guided actions. In addition, we compared neurobiological findings of the decision which action to perform with those referring to the decision whether or not to perform an action. Methods: Twenty-eight subjects participated in adapted go/nogo paradigms, including a voluntary selection condition allowing participants to (1) freely decide whether to press the response button or (2) to decide whether they wanted to press the response button with the right index finger or the left index finger. Results: The reaction times were increased when participants freely decided whether and how they wanted to respond compared to the go condition. Intentional processes were associated with a fronto-centrally located N2 and P3 potential. N2 and P3 amplitudes were increased during intentional actions compared to instructed responses (go). In addition, increased activity in the alpha-, beta- and gamma-frequency range was shown during voluntary behavior rather than during externally guided responses. Conclusion: These results may indicate that an additional cognitive process is needed for intentional actions compared to instructed behavior. However, the neural responses were comparatively independent of the kind of decision that was made (1) decision which action to perform; (2) decision whether or not to perform an action). Significance: The study demonstrates the importance of fronto-central alpha-, beta-, and gamma oscillations for voluntary behavior. PMID:26834680

  7. Hypoxia differentially regulates the mitogen- and stress-activated protein kinases. Role of Ca2+/CaM in the activation of MAPK and p38 gamma.

    PubMed

    Conrad, P W; Millhorn, D E; Beitner-Johnson, D

    2000-01-01

    Hypoxic/ischemic trauma is a primary factor in the pathology of various vascular, pulmonary, and cerebral disease states. Yet, the signaling mechanisms by which cells respond and adapt to changes in oxygen levels are not clearly established. The effects of hypoxia on the stress- and mitogen-activated protein kinase (SAPK and MAPK) signaling pathways were studied in PC12 cells. Exposure to moderate hypoxia (5% O2) was found to progressively stimulate phosphorylation and activation of p38 gamma in particular, and also p38 alpha, two isoforms of the p38 family of stress-activated protein kinases. In contrast, hypoxia had no effect on enzyme activity of p38 beta, p38 beta 2, p38 delta, or on JNK, another stress-activated protein kinase. Prolonged hypoxia also induced phosphorylation and activation of p42/p44 MAPK, although this activation was modest when compared to NGF and UV-induced activation. We further showed that activation of p38 gamma and MAPK during hypoxia requires calcium, as treatment with Ca(2+)-free media or the calmodulin antagonist, W13, blocked the activation of p38 gamma and MAPK, respectively. These studies demonstrate that an extremely typical physiological stress (hypoxia) causes selective activation of specific elements of the SAPKs and MAPKs, and identifies Ca+2/CaM as a critical upstream activator. PMID:10849670

  8. Fermi LAT detection of an increase of gamma-ray activity of S5 1044+71

    NASA Astrophysics Data System (ADS)

    D'Ammando, F.; Orienti, M.

    2014-01-01

    The Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope, has observed gamma-ray flaring activity from a source positionally consistent with the flat spectrum radio quasar S5 1044+71 (also known as 2FGL J1048.3+7144, Nolan et al. 2012, ApJS, 199, 31) with radio coordinates R.A.: 162.1150829 deg, Dec: 71.7266494 deg (J2000; Johnston et al. 1995, AJ, 110, 880) at redshift z=1.15 (Polatidis et al.

  9. A procedure for the standardization of gamma reference sources for quality assurance in activity measurements of radiopharmaceuticals.

    PubMed

    Oropesa, P; Serra, R; Gutiérrez, S; Hernández, A T

    2002-06-01

    A simplified procedure for the standardization of gamma reference sources, for use in quality assurance of activity measurements during production and application of radiopharmaceuticals in Cuban nuclear medicine laboratories, is described. The method is based on the reliable achievement of consistent measurements by both gamma-spectrometry and ionization chamber techniques, and allows to obtain reference sources with uncertainties lower than 2%. Experimental setup, validation procedure and typical results obtained for 99mTc, 131I, 201Tl and 153Sm are described and discussed. The method will serve also as a secondary reference system for radioactivity measurements in the country. PMID:12102334

  10. Gamma rays as an effective tool for removing undesirable color without adverse changes in biological activities of red beet extracts

    NASA Astrophysics Data System (ADS)

    Lee, Seung Sik; Lee, Eun Mi; Hong, Sung Hyun; Bai, Hyoung-Woo; Lee, In Chul; Chung, Byung Yeoup

    2012-08-01

    The ethanolic extracts of red beet (Beta vulgaris L.) hairy root were used to investigate the removal of color and improvement of biological activity for enhanced industrial applications. The extracts were exposed to gamma rays ranging from 2.5 to 30 kGy. The red beet hairy root is composed of two major red-colorants, betanin and isobetanin. Gamma ray radiation at 5 kGy remarkably reduced the levels of the major colorants by 94% and the reddish color was eliminated by doses greater than 10 kGy. Color removal was likely due to the gamma ray radiolysis of ethanol. Although details on the mechanism responsible for the decay of the chromophore have not been entirely determined, our results suggest that the free radicals that are produced during this process are capable of destroying the chromophore group in isobetanin, thus bleaching the substrate solution. In spite of the degradation of the major colorants, the biological activities of constituents of the extract such as DPPH radical scavenging and tyrosinase inhibition were negligibly affected by the gamma ray radiation up to 20 kGy. The antioxidant activity was 92.7% in control samples and 90.0-92.0% in irradiated samples (2.5-20 kGy), and a slight decrease to 87.5% was observed for gamma ray radiation at 30 kGy. In addition, tyrosinase inhibition activity has also the same pattern; the activity is slightly increased from 50.7% of control to 49.1-52.8% of irradiated samples (2.5-20 kGy) with a 46.8% at 30 kGy.

  11. SOLIDIFICATION TESTING FOR A HIGH ACTIVITY WASTESTREAM FROM THE SAVANNAH RIVER SITE USING GROUT AND GAMMA RADIATION SHEILDING MATERIALS - 10017

    SciTech Connect

    Burns, H.

    2009-11-10

    The U.S. Department of Energy (DOE) tasked MSE Technology Applications, Inc. (MSE) with evaluating grouts that include gamma radiation shielding materials to solidify surrogates of liquid aqueous radioactive wastes from across the DOE Complex. The Savannah River Site (SRS) identified a High Activity Waste (HAW) that will be treated and solidified at the Waste Solidification Building (WSB) for surrogate grout testing. The HAW, which is produced at the Mixed Oxide Fuel Fabrication Facility (MFFF), is an acidic aqueous wastestream generated by the alkaline treatment process and the aqueous purification process. The HAW surrogate was solidified using Portland cement with and without the inclusion of different gamma radiation shielding materials to determine the shielding material that is the most effective to attenuate gamma radiation for this application.

  12. Letter: Iatrogenic lipomatosis: a rare manifestation of treatment with a peroxisome proliferator-activated receptor gamma agonist.

    PubMed

    Femia, Alisa; Klein, Peter A

    2010-01-01

    Lipomas are common benign neoplasms of adipose tissue. Lipomatosis, the progressive appearance of multiple lipomas, is most often associated with specific congenital, familial, or idiopathic syndromes. In one reported case, the development of multiple lipomas occurred as a result of treatment with rosiglitazone, a peroxisome proliferator-activated receptor (PPAR) gamma agonist. We report a second case of lipomatosis occurring as a result of treatment with a PPAR gamma agonist. This case occurred in a 77-year-old woman who developed multiple lipomas two years after beginning treatment with pioglitazone, a PPAR gamma agonist. Histopathologic examination confirmed these lesions to be lipomas. Within four weeks of discontinuation of pioglitazone, regression of the lipomas began. We describe a case of PPAR agonist-induced lipoma formation, review relevant literature, and provide a molecular mechanism for this side effect. PMID:20409422

  13. Temporal Variations of Gamma-Ray for Detecting Crustal Activity Changes in the Longitudinal Valley, Eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Fu, C. C.; Wang, P. G.; Lee, L. C.; Lin, C. H.; Giuliani, G.; Ouzounov, D.

    2014-12-01

    A gamma-ray station was established along the Longitudinal Valley Fault, which is an extremely active high-angle thrust with NNE-striking on the boundary between Eurasia plate and Philippine Sea plate. Stresses arise in the crust in accordance with crustal deformations due to plate motions and geodynamic processes. Gamma-ray emission associated with the radioactive decay of radon is continuously recorded in the station, considered to be discharged into surface from deep source area. Fluctuations of gamma-ray data are found to show a clear inverse correction with atmospheric temperature. Based on the linear regression method, possible temperature effects can be removed and the corrected data can be obtained. Variations exceeding the normal trend can be used to identify events associated with geodynamic processes such as earthquake. These anomalies usually appeare as procursors a few days before the local earthquakes, which occur in eastern Taiwan. It is noted that there are two significant increases in the gamma-ray counting rate during the period of 20th to 25th March and the period of 22nd April to 1st May. These increases are observed one week before the earthquake swarm. Furthermore, a progressive anomalies were recorded two weeks before the Fanglin earthquake (ML = 5.9, May 21, 2014) located in the Longitudinal Valley area. A continuous monitoring on the multiple parameters can improve our understanding of the relationship between the observed gamma-ray variations and the regional crustal stress/strain in the area.

  14. Radio afterglow rebrightening: evidence for multiple active phases in gamma-ray burst central engines

    NASA Astrophysics Data System (ADS)

    Li, Long-Biao; Zhang, Zhi-Bin; Rice, Jared

    2015-09-01

    The rebrightening phenomenon is an interesting feature in some X-ray, optical, and radio afterglows of gamma-ray bursts (GRBs). Here, we propose a possible energy-supply assumption to explain the rebrightenings of radio afterglows, in which the central engine with multiple active phases can supply at least two GRB pulses in a typical GRB duration time. Considering the case of double pulses supplied by the central engine, the double pulses have separate physical parameters, except for the number density of the surrounding interstellar medium (ISM). Their independent radio afterglows are integrated by the ground detectors to form the rebrightening phenomenon. In this Letter, we firstly simulate diverse rebrightening light curves under consideration of different and independent physical parameters. Using this assumption, we also give our best fit to the radio afterglow of GRB 970508 at three frequencies of 1.43, 4.86, and 8.46 GHz. We suggest that the central engine may be active continuously at a timescale longer than that of a typical GRB duration time as many authors have suggested (e.g., Zhang et al., Astrophys. J. 787:66, 2014; Gao and Mészáros, Astrophys. J. 802:90, 2015), and that it may supply enough energy to cause the long-lasting rebrightenings observed in some GRB afterglows.

  15. [Thiazolidinediones in type 2 diabetes. Role of peroxisome proliferator-activated receptor gamma (PPARgamma)].

    PubMed

    Dubois, M; Vantyghem, M-C; Schoonjans, K; Pattou, F

    2002-12-01

    Thiazolidinediones (TZDs) form a new class of oral antidiabetic agents. They improve insulin sensitivity and reduce glycemia, lipidemia and insulinemia in patients with type 2 diabetes. Their mechanism is original, since they activate the nuclear receptor Peroxisome Proliferator-Activated Receptor gamma (PPARgamma), altering the expression of genes involved in glucose and lipid homeostasis. Stimulating PPARgamma improves insulin sensitivity via several mechanisms: 1) it raises the expression of GLUT4 glucose transporter; 2) it regulates release of adipocyte-derived signaling factors that affect insulin sensitivity in muscle, and 3) it contributes to a turn-over in adipose tissue, inducing the production of smaller, more insulin sensitive adipocytes. TZDs also affect free fatty acids (FFA) lipotoxicity on islets, improving pancreatic B-cell function. In addition, triglycerides and FFA levels are lowered by TZDs. Two TZDs, rosiglitazone and pioglitazone, have recently obtained the European commercial licence, but their use is restricted to the association with metformin or sulfonylureas. At the moment, they are indicated in type 2 diabetes but could be of interest in a broader array of diseases related to insulin resistance. As for side effects, rosiglitazone and pioglitazone may cause increased plasma volume, edema and dose-related weight gain. TZDs offer an attractive option in the treatment of type 2 diabetes, though it may be too soon to determine if they prevent vascular complications, as do other oral antidiabetic agents. An important issue for the future will be to assess the influence of weight gain in the long time. PMID:12527853

  16. Peroxisome proliferator-activated receptor gamma agonists as insulin sensitizers: from the discovery to recent progress.

    PubMed

    Cho, Nobuo; Momose, Yu

    2008-01-01

    An epidemic of metabolic diseases including type 2 diabetes and obesity is undermining the health of people living in industrialized societies. There is an urgent need to develop innovative therapeutics. The peroxisome proliferator-activated receptor gamma (PPARgamma) is one of the ligand-activated transcription factors in the nuclear hormone receptor superfamily and a pivotal regulator of glucose and lipid homeostasis. The discovery of PPARgamma as a target of multimodal insulin sensitizers, represented by thiazolidinediones (TZDs), has attracted remarkable scientific interest and had a great impact on the pharmaceutical industry. With the clinical success of the PPARgamma agonists, pioglitazone (Actos) and rosiglitazone (Avandia), development of novel and potent insulin-sensitizing agents with diverse clinical profiles has been accelerated. Currently, a number of PPARgamma agonists from different chemical classes and with varying pharmacological profiles are being developed. Despite quite a few obstacles to the development of PPAR-related drugs, PPARgamma-targeted agents still hold promise. There are new concepts and encouraging evidence emerging that suggest this class can yield improved anti-diabetic agents. This review covers the discovery of TZDs, provides an overview of PPARgamma including the significance of PPARgamma as a drug target, describes the current status of a wide variety of novel PPARgamma ligands including PPAR dual and pan agonists and selective PPARgamma modulators (SPPARgammaMs), and highlights new approaches for identifying agents targeting PPARgamma in the treatment of type 2 diabetes. PMID:19075761

  17. Synchronous and Asynchronous Theta and Gamma Activity during Episodic Memory Formation

    PubMed Central

    Burke, John F.; Zaghloul, Kareem A.; Jacobs, Joshua; Williams, Ryan B.; Sperling, Michael R.; Sharan, Ashwini D.; Kahana, Michael J.

    2013-01-01

    To test the hypothesis that neural oscillations synchronize to mediate memory encoding, we analyzed electrocorticographic recordings taken as 68 human neurosurgical patients studied and subsequently recalled lists of common words. To the extent that changes in spectral power reflect synchronous oscillations, we would expect those power changes to be accompanied by increases in phase synchrony between the region of interest and neighboring brain areas. Contrary to the hypothesized role of synchronous gamma oscillations in memory formation, we found that many key regions that showed power increases during successful memory encoding also exhibited decreases in global synchrony. Similarly, cortical theta activity that decreases during memory encoding exhibits both increased and decreased global synchrony depending on region and stage of encoding. We suggest that network synchrony analyses, as used here, can help to distinguish between two major types of spectral modulations: (1) those that reflect synchronous engagement of regional neurons with neighboring brain areas, and (2) those that reflect either asynchronous modulations of neural activity or local synchrony accompanied by global disengagement from neighboring regions. We show that these two kinds of spectral modulations have distinct spatiotemporal profiles during memory encoding. PMID:23283342

  18. Effect of heterodimer partner RXR{alpha} on PPAR{gamma} activation function-2 helix in solution

    SciTech Connect

    Lu Jianyun Chen Minghe; Stanley, Susan E.; Li, Ellen

    2008-01-04

    The structural mechanism of allosteric communication between retinoid X receptor (RXR) and its heterodimer partners remains controversial. As a first step towards addressing this question, we report a nuclear magnetic resonance (NMR) study on the GW1929-bound peroxisome proliferator-activated receptor gamma (PPAR{gamma}) ligand-binding domain (LBD) with and without the 9-cis-retinoic acid (9cRA)-bound RXR{alpha} LBD. Sequence-specific {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, and {sup 13}CO resonance assignments have been established for over 95% of the 275 residues in the PPAR{gamma} LBD monomer. The {sup 1}HN, {sup 15}N, and {sup 13}CO chemical shift perturbations induced by the RXR{alpha} LBD binding are located at not only the heterodimer interface that includes the C-terminal residue Y477 but also residues Y473 and K474 in the activation function-2 (AF-2) helix. This result suggests that 9cRA-bound RXR{alpha} can affect the PPAR{gamma} AF-2 helix in solution and demonstrates that NMR is a powerful new tool for studying the mechanism of allosteric ligand activation in RXR heterodimers.

  19. Glutathione S-transferase and gamma-glutamyl transpeptidase activities in cultured rat hepatocytes treated with tocotrienol and tocopherol.

    PubMed

    Ong, F B; Wan Ngah, W Z; Shamaan, N A; Md Top, A G; Marzuki, A; Khalid, A K

    1993-09-01

    1. The effect of tocotrienol and tocopherol on glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (GGT) activities in cultured rat hepatocytes were investigated. 2. Tocotrienol and tocopherol significantly decreased GGT activities at 5 days in culture but tocotrienol also significantly decreased GGT activities at 1-2 days. 3. Tocotrienol and tocopherol treatment significantly decreased GST activities at 3 days compared to the control but tocotrienol also decreased GST activities at 1-3 days. 4. Tocotrienol showed a more pronounced effect at a dosage of greater than 50 microM tocotrienol at 1-3 days in culture compared to the control. PMID:7903615

  20. The signalling pathways of interleukin-6 and gamma interferon converge by the activation of different transcription factors which bind to common responsive DNA elements.

    PubMed Central

    Yuan, J; Wegenka, U M; Lütticken, C; Buschmann, J; Decker, T; Schindler, C; Heinrich, P C; Horn, F

    1994-01-01

    Interleukin-6 (IL-6) and gamma interferon (IFN-gamma) induce a partially overlapping set of genes, including the genes for interferon regulatory factor 1 (IRF-1), intercellular adhesion molecule 1 (ICAM-1), and the acute-phase protein alpha 2-macroglobulin. We report here that the rat alpha 2-macroglobulin promoter is activated by IFN-gamma in human hepatoma (HepG2) cells and that the IFN-gamma response element maps to the same site previously defined as the acute-phase response element (APRE), which binds the IL-6-activated transcription factor APRF (acute-phase response factor). As was reported for fibroblasts, the IFN-gamma-regulated transcription factor GAF is phosphorylated at tyrosine after IFN-gamma treatment of HepG2 cells. IFN-gamma posttranslationally activates a protein which specifically binds to the alpha 2-macroglobulin APRE. This protein is shown to be identical or closely related to GAF. Although APRF and GAF are shown to represent different proteins, their binding sequence specificities are very similar. APRF and GAF bind equally well to the APRE sequences of various acute-phase protein genes as well as to the IFN-gamma response elements of the IRF-1, ICAM-1, and other IFN-gamma-inducible genes. Transient transfection analysis revealed that the IFN-gamma response elements of the IRF-1 and ICAM-1 promoters are able to confer responsiveness to both IFN-gamma and IL-6 onto a heterologous promoter. Therefore, APRF and GAF are likely to be involved in the transcriptional induction of these immediate-early genes by IL-6 and IFN-gamma, respectively. Taken together, these results demonstrate that two functionally distinct hormones, IL-6 and IFN-gamma, act through common regulatory elements to which different transcription factors sharing almost the same sequence specificity bind. Images PMID:7509445

  1. Up-regulation of gamma-glutamyl transpeptidase (GGT) activity in growth perturbed C6 astrocytes.

    PubMed

    Mares, V; Malík, R; Lisá, V; Sedo, A

    2005-05-20

    Activity of gamma-glutamyl transpeptidase (GGT) was studied in astrocyte-like C6 glial cells modulated in growth and maturation by different concentration of serum and dibutyryl cyclic AMP (Db-cAMP) supplement in culture medium. After reduction of serum concentration from 10% to 0.1%, the number of GGT positive cells determined histochemically increased 3.1 times and the GGT activity/mg protein in whole cell lysates was 5.1 times higher. In cultures with 0.1% serum + Db-cAMP, the histochemically and biochemically assayed GGT activity exceeded 5.1 and 7.9 times the values measured in control 10% serum cultures, respectively. The up-regulation of GGT was accompanied by an inhibition of proliferation, enhanced differentiation and hypertrophy of cells. In addition, the process of metabolic perturbation and/or cellular stress was revealed in these cultures by the (i) growth-support release followed by shrinkage and death of a small number of cells and (ii) higher oxidation of 2'7'dichlorofluorescein diacetate to its fluorescent form in the adherent/viable cells. The observed up-regulation of GGT is considered to primarily reflect increased metabolism of glutathione and/or the maintenance of the redox potential in cells stressed by sub-optimal concentration of serum and Db-cAMP supplement. The concomitant cellular hypertrophy and differentiation and their relationship to increased activity of GGT await further investigation. The study suggests that up-regulation of GGT can contribute to adaptation of astrocytic cells to metabolic and/or oxidative perturbances occurring under various pathological conditions, including radiation- and drug-induced toxicity. PMID:15893589

  2. Controversial role of gamma-glutamyl transferase activity in cisplatin nephrotoxicity.

    PubMed

    Fliedl, Lukas; Wieser, Matthias; Manhart, Gabriele; Gerstl, Matthias P; Khan, Abdulhameed; Grillari, Johannes; Grillari-Voglauer, Regina

    2014-01-01

    Nephrotoxicity of chemotherapeutics is a major hindrance in the treatment of various tumors. Therefore, test systems that reflect mechanisms of human kidney toxicity are necessary, and to reduce animal testing cell culture based systems have to be developed. One cell type that is of specific interest in this regard are renal proximal tubular epithelial cells, as they reabsorb substances from human primary urine filtrates and thus are exposed to urinary excreted xenobiotics and are a major target of cisplatin toxicity. While animal studies using gamma glutamyl transferase (GGT) knock-out mice or GGT inhibitors show that GGT activity increases kidney toxicity of cisplatin, the use of various cell models gives contradictory results. We therefore used a cell panel of immortalized human renal proximal tubular epithelial (RPTECs) cell lines differing in GGT activity. Low GGT activity resulted in high cisplatin sensitivity, as observed in RPTEC-SV40 cells or after siRNA mediated knock-down of GGT in RPTEC/TERT1 cells that have high GGT activity. However, the addition of GGT did not rescue, but also increased cisplatin sensitivity and adding GGT inhibitor as well as substrate (glutathione) or product (cysteinyl-glycine) of GGT resulted in decreased sensitivity. While our data suggest that the use of cell panels are of value in toxicology and toxicogenomics, they also emphasize on the complex interplay of toxins with the intracellular and extracellular microenvironment. In addition, we hypothesize that especially epithelial barrier formation and polarity of RPTECs need to be considered in toxicity models to validly predict the in vivo situation. PMID:24664430

  3. Effect of gamma irradiation on the pigments and the biological activities of methanolic extracts from leaves of centipedegrass (Eremochloa ophiuroides Munro)

    NASA Astrophysics Data System (ADS)

    Lee, Eun Mi; Lee, Seung Sik; Bai, Hyoung-Woo; Cho, Jae-Young; Kim, Tae Hoon; Chung, Byung Yeoup

    2013-10-01

    Extracts from centipedegrass (Eremochloa ophiuroides Munro) have been previously identified as having beneficial effects medically and cosmetically. In this study, the effects of gamma irradiation on pigment removal and biological activities of centipedegrass extracts to promote industrial application were investigated. The methanolic extracts were exposed to gamma irradiation at dose ranging from 2 to 20 kGy. The major pigments of centipedegrass extracts, cyanidin-3-O-glucoside and cyanidin-3-O-(6″-malonyl-)glucoside, were found to be effectively removed by gamma irradiation above 10 kGy. Although the reddish-orange color of the cyanidins was markedly decreased by gamma irradiation, the biological activities were relatively unaffected. The biological activities such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, inhibition of tyrosinase activity, and inhibition of elastase activity in methanolic extracts were modulated from 50.5% to 70.2%, from 50.9% to 65.8% and from 65.6% to 94.0%, respectively. Surprisingly, the biological activities have the highest activities after 6-8 kGy of gamma irradiation. These results indicate that despite pigment degradation, biological activities were maintained or increased by gamma irradiation. Based on these results, gamma irradiation may be a useful tool to remove the undesirable reddish-orange color present in centipedegrass without any loss of biological activities, thereby promoting its utility in industrial applications such as manufacturing of cosmetic products.

  4. Biochemical signal transmitted by Fc gamma receptors: phospholipase A2 activity of Fc gamma 2b receptor of murine macrophage cell line P388D1.

    PubMed Central

    Suzuki, T; Saito-Taki, T; Sadasivan, R; Nitta, T

    1982-01-01

    The detergent lysate of the P388D1 macrophage cell line was subjected to affinity chromatography on two different media, Sepharose coupled to heat-aggregated human IgG (IgG-Sepharose) and Sepharose coupled to the phosphatidylcholine analog rac-1-(9-carboxyl)nonyl-2-hexadecylglycero-3-phosphocholine (PC-Sepharose). Both IgG- and phosphatidylcholine-binding proteins were further purified by Sephadex G-100 gel filtration and isoelectric focusing in the presence of 6 M urea. The isolated IgG-binding proteins specifically bound to IgG2a, but not to IgG2b, whereas the isolated phosphatidylcholine-binding proteins specifically bound to IgG2b but not to IgG2a. Phosphatidylcholine-binding proteins possessed a typical phospholipase A2 activity (phosphatide 2-acylhydrolase, EC 3.1.1.4), which was maximal (10 mumol/min per mg of protein) at pH 9.5, depended on Ca2+, and was specific for cleavage of fatty acid from the C-2 position of the glycerol backbone of phosphatidylcholine. The noted enzymatic activity was augmented 4-fold by preincubating phosphatidylcholine-binding proteins with heat-aggregated murine IgG2b but not with IgG2a. IgG-binding proteins, on the other hand, are devoid of any detectable phospholipase A2 activity. Thus, the functional significance of Fc gamma 2b receptor of P388D1 macrophage cell line would be the generation of phospholipase A2 activity at the cell surface upon specific binding to Fc gamma 2b fragment. PMID:6804944

  5. Analysis of Induced Gamma Activation by D-T Neutrons in Selected Fusion Reactor Relevant Materials with EAF-2010

    NASA Astrophysics Data System (ADS)

    Klix, Axel; Fischer, Ulrich; Gehre, Daniel

    2016-02-01

    Samples of lanthanum, erbium and titanium which are constituents of structural materials, insulating coatings and tritium breeder for blankets of fusion reactor designs have been irradiated in a fusion peak neutron field. The induced gamma activities were measured and the results were used to check calculations with the European activation system EASY-2010. Good agreement for the prediction of major contributors to the contact dose rate of the materials was found, but for minor contributors the calculation deviated up to 50%.

  6. Constitutive Smad signaling and Smad-dependent collagen gene expression in mouse embryonic fibroblasts lacking peroxisome proliferator-activated receptor-{gamma}

    SciTech Connect

    Ghosh, Asish K Wei, Jun; Wu, Minghua; Varga, John

    2008-09-19

    Transforming growth factor-{beta} (TGF-{beta}), a potent inducer of collagen synthesis, is implicated in pathological fibrosis. Peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) is a nuclear hormone receptor that regulates adipogenesis and numerous other biological processes. Here, we demonstrate that collagen gene expression was markedly elevated in mouse embryonic fibroblasts (MEFs) lacking PPAR-{gamma} compared to heterozygous control MEFs. Treatment with the PPAR-{gamma} ligand 15d-PGJ{sub 2} failed to down-regulate collagen gene expression in PPAR-{gamma} null MEFs, whereas reconstitution of these cells with ectopic PPAR-{gamma} resulted in their normalization. Compared to control MEFs, PPAR-{gamma} null MEFs displayed elevated levels of the Type I TGF-{beta} receptor (T{beta}RI), and secreted more TGF-{beta}1 into the media. Furthermore, PPAR-{gamma} null MEFs showed constitutive phosphorylation of cellular Smad2 and Smad3, even in the absence of exogenous TGF-{beta}, which was abrogated by the ALK5 inhibitor SB431542. Constitutive Smad2/3 phosphorylation in PPAR-{gamma} null MEFs was associated with Smad3 binding to its cognate DNA recognition sequences, and interaction with coactivator p300 previously implicated in TGF-{beta} responses. Taken together, these results indicate that loss of PPAR-{gamma} in MEFs is associated with upregulation of collagen synthesis, and activation of intracellular Smad signal transduction, due, at least in part, to autocrine TGF-{beta} stimulation.

  7. Interleukin 10 inhibits macrophage microbicidal activity by blocking the endogenous production of tumor necrosis factor alpha required as a costimulatory factor for interferon gamma-induced activation.

    PubMed Central

    Oswald, I P; Wynn, T A; Sher, A; James, S L

    1992-01-01

    Interleukin 10 (IL-10) inhibits interferon gamma-induced macrophage activation for cytotoxicity against larvae of the human parasite Schistosoma mansoni by suppressing production of the toxic effector molecule nitric oxide (NO). In this study, the mechanism of IL-10 action was identified as inhibition of endogenous tumor necrosis factor alpha (TNF-alpha) production by interferon gamma-activated macrophages. TNF-alpha appears to serve as a cofactor for interferon gamma-mediated activation, since both schistosomulum killing and NO production were inhibited by anti-TNF-alpha antibody, whereas TNF-alpha alone was unable to stimulate these macrophage functions. IL-10 blocked TNF-alpha production by interferon gamma-treated macrophages at the levels of both protein and mRNA synthesis. Addition of exogenous TNF-alpha reversed IL-10-mediated suppression of macrophage cytotoxic activity as well as NO production. Likewise, addition of a macrophage-triggering agent (bacterial lipopolysaccharide or muramyl dipeptide), which induced the production of TNF-alpha, also reversed the suppressive effect of IL-10 on cytotoxic function. In contrast to IL-10, two other cytokines, IL-4 and transforming growth factor beta, which also inhibit macrophage activation for schistosomulum killing and NO production, did not substantially suppress endogenous TNF-alpha production. These results, therefore, describe a separate pathway by which macrophage microbicidal function is inhibited by the down-regulatory cytokine IL-10. Images PMID:1528880

  8. Phosphorylation-dependent sumoylation regulates estrogen-related receptor-alpha and -gamma transcriptional activity through a synergy control motif.

    PubMed

    Tremblay, Annie M; Wilson, Brian J; Yang, Xiang-Jiao; Giguère, Vincent

    2008-03-01

    Interplay between different posttranslational modifications of transcription factors is an important mechanism to achieve an integrated regulation of gene expression. For the estrogen-related receptors (ERRs) alpha and gamma, regulation by posttranslational modifications is still poorly documented. Here we show that transcriptional repression associated with the ERR amino-terminal domains is mediated through sumoylation at a conserved phospho-sumoyl switch, psiKxEPxSP, that exists within a larger synergy control motif. Arginine substitution of the sumoylatable lysine residue or alanine substitution of a nearby phosphorylatable serine residue (serine 19 in ERRalpha) increased the transcriptional activity of both ERRalpha and -gamma. In addition, phospho-mimetic substitution of the serine residue with aspartate restored the sumoylation and transcriptional repression activity. The increased transcriptional activity of the sumoylation-deficient mutants was more pronounced in the presence of multiple adjacent ERR response elements. We also identified protein inhibitor of activated signal transducer and activator of transcription y as an interacting partner and a small ubiquitin-related modifier E3 ligase for ERRalpha. Importantly, analysis with a phospho-specific antibody revealed that sumoylation of ERRalpha in mouse liver requires phosphorylation of serine 19. Taken together, these results show that the interplay of phosphorylation and sumoylation in the amino-terminal domain provides an additional mechanism to regulate the transcriptional activity of ERRalpha and -gamma. PMID:18063693

  9. Rapid and transient activation of gamma/delta T cells to interferon gamma production, NK cell-like killing and antigen processing during acute virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gamma/delta T cells are the majority peripheral blood T cells in young cattle. The role of gamma/delta T cells in innate responses against infection with foot-and-mouth disease virus (FMDV) was analyzed on 5 consecutive days following infection. Before infection, bovine gamma/delta T cells expressed...

  10. The associations of physical activity and adiposity with alanine aminotransferase and gamma-glutamyltransferase.

    PubMed

    Lawlor, Debbie A; Sattar, Naveed; Smith, George Davey; Ebrahim, Shah

    2005-06-01

    The mechanisms linking obesity and inactivity to diabetes mellitus are unclear. Recent studies have shown associations of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) with diabetes. In a random sample of 3,789 British women aged 60-79 years, the authors examined the associations of obesity and physical activity with ALT and GGT (1999-2001). Both body mass index and waist:hip ratio were independently (of each other, physical activity, alcohol consumption, smoking, and childhood and adulthood social class) positively and linearly associated with ALT and GGT. In adjusted models, a one-standard-deviation increase in body mass index was associated with a 0.46-units/liter (95% confidence interval (CI): 0.16, 0.75) increase in ALT and a 2.14-units/liter (95% CI: 0.99, 3.30) increase in GGT. Similar results for a one-standard-deviation increase in waist:hip ratio were 13.96 (95% CI: 10.44, 17.48) for ALT and 39.44 (95% CI: 25.89, 52.98) for GGT. Frequency of physical activity was inversely and linearly associated with GGT in fully adjusted models, but the inverse association with ALT was attenuated towards the null after adjustment for body mass index and waist:hip ratio. Adjustment for ALT and GGT resulted in some attenuation of the strong linear associations of body mass index and waist:hip ratio with diabetes. These findings provide some support for the suggestion that the relation between obesity and diabetes is, at least in part, mediated by liver pathology. PMID:15901629