Sample records for katrin erg veiko

  1. Status of the neutrino mass experiment KATRIN

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bornschein, L.; Bornschein, B.; Sturm, M.

    The most sensitive way to determine the neutrino mass scale without further assumptions is to measure the shape of a tritium beta spectrum near its kinematic end-point. Tritium is the nucleus of choice because of its low endpoint energy, superallowed decay and simple atomic structure. Within an international collaboration the Karlsruhe Tritium Neutrino experiment (KATRIN) is currently being built up at KIT. KATRIN will allow a model-independent measurement of the neutrino mass scale with an expected sensitivity of 0.2 eV/c{sup 2} (90% CL). KATRIN will use a source of ultrapure molecular tritium. This contribution presents the status of the KATRINmore » experiment, thereby focusing on its Calibration and Monitoring System (CMS), which is the last component being subject to research/development. After a brief overview of the KATRIN experiment in Section II the CMS is introduced in Section III. In Section IV the Beta Induced X-Ray Spectroscopy (BIXS) as method of choice to monitor the tritium activity of the KATRIN source is described and first results are presented.« less

  2. Focal-plane detector system for the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Amsbaugh, J. F.; Barrett, J.; Beglarian, A.; Bergmann, T.; Bichsel, H.; Bodine, L. I.; Bonn, J.; Boyd, N. M.; Burritt, T. H.; Chaoui, Z.; Chilingaryan, S.; Corona, T. J.; Doe, P. J.; Dunmore, J. A.; Enomoto, S.; Formaggio, J. A.; Fränkle, F. M.; Furse, D.; Gemmeke, H.; Glück, F.; Harms, F.; Harper, G. C.; Hartmann, J.; Howe, M. A.; Kaboth, A.; Kelsey, J.; Knauer, M.; Kopmann, A.; Leber, M. L.; Martin, E. L.; Middleman, K. J.; Myers, A. W.; Oblath, N. S.; Parno, D. S.; Peterson, D. A.; Petzold, L.; Phillips, D. G.; Renschler, P.; Robertson, R. G. H.; Schwarz, J.; Steidl, M.; Tcherniakhovski, D.; Thümmler, T.; Van Wechel, T. D.; VanDevender, B. A.; Vöcking, S.; Wall, B. L.; Wierman, K. L.; Wilkerson, J. F.; Wüstling, S.

    2015-04-01

    The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.

  3. Focal-plane detector system for the KATRIN experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Amsbaugh, J. F.; Barrett, J.; Beglarian, A.

    Here, the local plane detector system for the KArlsiuhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high vacuum system, a high vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system, It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.

  4. Focal-plane detector system for the KATRIN experiment

    DOE PAGES

    Amsbaugh, J. F.; Barrett, J.; Beglarian, A.; ...

    2015-01-09

    Here, the local plane detector system for the KArlsiuhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high vacuum system, a high vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system, It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation.

  5. Methodology and application of high performance electrostatic field simulation in the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Corona, Thomas

    The Karlsruhe Tritium Neutrino (KATRIN) experiment is a tritium beta decay experiment designed to make a direct, model independent measurement of the electron neutrino mass. The experimental apparatus employs strong ( O[T]) magnetostatic and (O[10 5 V/m]) electrostatic fields in regions of ultra high (O[10-11 mbar]) vacuum in order to obtain precise measurements of the electron energy spectrum near the endpoint of tritium beta-decay. The electrostatic fields in KATRIN are formed by multiscale electrode geometries, necessitating the development of high performance field simulation software. To this end, we present a Boundary Element Method (BEM) with analytic boundary integral terms in conjunction with the Robin Hood linear algebraic solver, a nonstationary successive subspace correction (SSC) method. We describe an implementation of these techniques for high performance computing environments in the software KEMField, along with the geometry modeling and discretization software KGeoBag. We detail the application of KEMField and KGeoBag to KATRIN's spectrometer and detector sections, and demonstrate its use in furthering several of KATRIN's scientific goals. Finally, we present the results of a measurement designed to probe the electrostatic profile of KATRIN's main spectrometer in comparison to simulated results.

  6. Forecasting neutrino masses from combining KATRIN and the CMB observations: Frequentist and Bayesian analyses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Host, Ole; Lahav, Ofer; Abdalla, Filipe B.

    We present a showcase for deriving bounds on the neutrino masses from laboratory experiments and cosmological observations. We compare the frequentist and Bayesian bounds on the effective electron neutrino mass m{sub {beta}} which the KATRIN neutrino mass experiment is expected to obtain, using both an analytical likelihood function and Monte Carlo simulations of KATRIN. Assuming a uniform prior in m{sub {beta}}, we find that a null result yields an upper bound of about 0.17 eV at 90% confidence in the Bayesian analysis, to be compared with the frequentist KATRIN reference value of 0.20 eV. This is a significant difference whenmore » judged relative to the systematic and statistical uncertainties of the experiment. On the other hand, an input m{sub {beta}}=0.35 eV, which is the KATRIN 5{sigma} detection threshold, would be detected at virtually the same level. Finally, we combine the simulated KATRIN results with cosmological data in the form of present (post-WMAP) and future (simulated Planck) observations. If an input of m{sub {beta}}=0.2 eV is assumed in our simulations, KATRIN alone excludes a zero neutrino mass at 2.2{sigma}. Adding Planck data increases the probability of detection to a median 2.7{sigma}. The analysis highlights the importance of combining cosmological and laboratory data on an equal footing.« less

  7. Sedimentary record of erg migration

    NASA Astrophysics Data System (ADS)

    Porter, M. L.

    1986-06-01

    The sedimentary record of erg (eolian sand sea) migration consists of an idealized threefold division of sand-sea facies sequences. The basal division, here termed the fore-erg, is composed of a hierarchy of eolian sand bodies contained within sediments of the flanking depositional environment. These sand bodies consist of eolian strata deposited by small dune complexes, zibars, and sand sheets. The fore-erg represents the downwind, leading edge of the erg and records the onset of eolian sedimentation. Basin subsidence coupled with erg migration places the medial division, termed the central erg, over the fore-erg strata. The central erg, represented by a thick accumulation of large-scale, cross-stratified sandstone, is the product of large draa complexes. Eolian influence on regional sedimentation patterns is greatest in the central erg, and most of the sand transported and deposited in the erg is contained within this region. Reduction in sand supply and continued erg migration will cover the central-erg deposits with a veneer of back-erg deposits. This upper division of the erg facies sequence resembles closely the fore-erg region. Similar types of eolian strata are present and organized in sand bodies encased in sediments of the upwind flanking depositional environment(s). Back-erg deposits may be thin due to limited eolian influence on sedimentation or incomplete erg migration, or they may be completely absent because of great susceptibility to postdepositional erosion. Tectonic, climatic, and eustatic influences on sand-sea deposition will produce distinctive variations or modifications of the idealized erg facies sequence. The resulting variants in the sedimentary record of erg migration are illustrated with ancient examples from western North America, Europe, southern Africa, and South America.

  8. The ERG Science Center

    NASA Astrophysics Data System (ADS)

    Miyoshi, Yoshizumi; Hori, Tomoaki; Shoji, Masafumi; Teramoto, Mariko; Chang, T. F.; Segawa, Tomonori; Umemura, Norio; Matsuda, Shoya; Kurita, Satoshi; Keika, Kunihiro; Miyashita, Yukinaga; Seki, Kanako; Tanaka, Yoshimasa; Nishitani, Nozomu; Kasahara, Satoshi; Yokota, Shoichiro; Matsuoka, Ayako; Kasahara, Yoshiya; Asamura, Kazushi; Takashima, Takeshi; Shinohara, Iku

    2018-06-01

    The Exploration of energization and Radiation in Geospace (ERG) Science Center serves as a hub of the ERG project, providing data files in a common format and developing the space physics environment data analysis software and plug-ins for data analysis. The Science Center also develops observation plans for the ERG (Arase) satellite according to the science strategy of the project. Conjugate observations with other satellites and ground-based observations are also planned. These tasks contribute to the ERG project by achieving quick analysis and well-organized conjugate ERG satellite and ground-based observations.

  9. First transmission of electrons and ions through the KATRIN beamline

    NASA Astrophysics Data System (ADS)

    Arenz, M.; Baek, W.-J.; Beck, M.; Beglarian, A.; Behrens, J.; Bergmann, T.; Berlev, A.; Besserer, U.; Blaum, K.; Bode, T.; Bornschein, B.; Bornschein, L.; Brunst, T.; Buzinsky, N.; Chilingaryan, S.; Choi, W. Q.; Deffert, M.; Doe, P. J.; Dragoun, O.; Drexlin, G.; Dyba, S.; Edzards, F.; Eitel, K.; Ellinger, E.; Engel, R.; Enomoto, S.; Erhard, M.; Eversheim, D.; Fedkevych, M.; Fischer, S.; Formaggio, J. A.; Fränkle, F. M.; Franklin, G. B.; Friedel, F.; Fulst, A.; Gil, W.; Glück, F.; Gonzalez Ureña, A.; Grohmann, S.; Grössle, R.; Gumbsheimer, R.; Hackenjos, M.; Hannen, V.; Harms, F.; Haußmann, N.; Heizmann, F.; Helbing, K.; Herz, W.; Hickford, S.; Hilk, D.; Hillesheimer, D.; Howe, M. A.; Huber, A.; Jansen, A.; Kellerer, J.; Kernert, N.; Kippenbrock, L.; Kleesiek, M.; Klein, M.; Kopmann, A.; Korzeczek, M.; Kovalík, A.; Krasch, B.; Kraus, M.; Kuckert, L.; Lasserre, T.; Lebeda, O.; Letnev, J.; Lokhov, A.; Machatschek, M.; Marsteller, A.; Martin, E. L.; Mertens, S.; Mirz, S.; Monreal, B.; Naumann, U.; Neumann, H.; Niemes, S.; Off, A.; Ortjohann, H.-W.; Osipowicz, A.; Otten, E.; Parno, D. S.; Pollithy, A.; Poon, A. W. P.; Priester, F.; Ranitzsch, P. C.-O.; Rest, O.; Robertson, R. G. H.; Roccati, F.; Rodenbeck, C.; Röllig, M.; Röttele, C.; Ryšavý, M.; Sack, R.; Saenz, A.; Schimpf, L.; Schlösser, K.; Schlösser, M.; Schönung, K.; Schrank, M.; Seitz-Moskaliuk, H.; Sentkerestiová, J.; Sibille, V.; Slezák, M.; Steidl, M.; Steinbrink, N.; Sturm, M.; Suchopar, M.; Suesser, M.; Telle, H. H.; Thorne, L. A.; Thümmler, T.; Titov, N.; Tkachev, I.; Trost, N.; Valerius, K.; Vénos, D.; Vianden, R.; Vizcaya Hernández, A. P.; Weber, M.; Weinheimer, C.; Weiss, C.; Welte, S.; Wendel, J.; Wilkerson, J. F.; Wolf, J.; Wüstling, S.; Zadoroghny, S.

    2018-04-01

    The Karlsruhe Tritium Neutrino (KATRIN) experiment is a large-scale effort to probe the absolute neutrino mass scale with a sensitivity of 0.2 eV (90% confidence level), via a precise measurement of the endpoint spectrum of tritium β-decay. This work documents several KATRIN commissioning milestones: the complete assembly of the experimental beamline, the successful transmission of electrons from three sources through the beamline to the primary detector, and tests of ion transport and retention. In the First Light commissioning campaign of autumn 2016, photoelectrons were generated at the rear wall and ions were created by a dedicated ion source attached to the rear section; in July 2017, gaseous 83mKr was injected into the KATRIN source section, and a condensed 83mKr source was deployed in the transport section. In this paper we describe the technical details of the apparatus and the configuration for each measurement, and give first results on source and system performance. We have successfully achieved transmission from all four sources, established system stability, and characterized many aspects of the apparatus.

  10. Measurement and reduction of low-level radon background in the KATRIN experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fränkle, F. M.

    The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c{sup 2}. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn)more » atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.« less

  11. Measurement and reduction of low-level radon background in the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Fränkle, F. M.

    2013-08-01

    The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c2. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn) atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.

  12. Dynamics of hERG closure allow novel insights into hERG blocking by small molecules.

    PubMed

    Schmidtke, Peter; Ciantar, Marine; Theret, Isabelle; Ducrot, Pierre

    2014-08-25

    Today, drug discovery routinely uses experimental assays to determine very early if a lead compound can yield certain types of off-target activity. Among such off targets is hERG. The ion channel plays a primordial role in membrane repolarization and altering its activity can cause severe heart arrhythmia and sudden death. Despite routine tests for hERG activity, rather little information is available for helping medicinal chemists and molecular modelers to rationally circumvent hERG activity. In this article novel insights into the dynamics of hERG channel closure are described. Notably, helical pairwise closure movements have been observed. Implications and relations to hERG inactivation are presented. Based on these dynamics novel insights on hERG blocker placement are presented, compared to literature, and discussed. Last, new evidence for horizontal ligand positioning is shown in light of former studies on hERG blockers.

  13. A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Behrens, J.; Ranitzsch, P. C.-O.; Beck, M.; Beglarian, A.; Erhard, M.; Groh, S.; Hannen, V.; Kraus, M.; Ortjohann, H.-W.; Rest, O.; Schlösser, K.; Thümmler, T.; Valerius, K.; Wierman, K.; Wilkerson, J. F.; Winzen, D.; Zacher, M.; Weinheimer, C.

    2017-06-01

    The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200 {meV/c^2} (90% C. L.) by a precision measurement of the shape of the tritium β -spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software "Kassiopeia", which was developed in the KATRIN collaboration over recent years.

  14. Ex Vivo ERG analysis of photoreceptors using an In Vivo ERG system

    PubMed Central

    Vinberg, Frans; Kolesnikov, Alexander V.; Kefalov, Vladimir J.

    2014-01-01

    The Function of the retina and effects of drugs on it can be assessed by recording transretinal voltage across isolated retina that is perfused with physiological medium. However, building ex vivo ERG apparatus requires substantial amount of time, resources and expertise. Here we adapted a commercial in vivo ERG system for transretinal ERG recordings from rod and cone photoreceptors and compared rod and cone signalling between ex vivo and in vivo environments. We found that the rod and cone a- and b-waves recorded with the transretinal ERG adapter and a standard in vivo ERG system are comparable to those obtained from live anesthetized animals. However, ex vivo responses are somewhat slower and their oscillatory potentials are suppressed as compared to those recorded in vivo. We found that rod amplification constant (A) was comparable between ex vivo and in vivo conditions, ∼10 - 30 s-2 depending on the choice of response normalization. We estimate that the A in cones is between 3 and 6 s-2 in ex vivo conditions and by assuming equal A in vivo we arrive to light funnelling factor of 3 for cones in the mouse retina. The ex vivo ERG adapter provides a simple and affordable alternative to designing a custom-built transretinal recordings setup for the study of photoreceptors. Our results provide a roadmap to the rigorous quantitative analysis of rod and cone responses made possible with such a system. PMID:24959652

  15. ERG Oncoprotein Expression in Prostate Cancer: Clonal Progression of ERG-Positive Tumor Cells and Potential for ERG-Based Stratification

    DTIC Science & Technology

    2010-01-01

    staining results as ERG positive or negative. Analysis of ERG mRNA by branched-chain DNA ( bDNA ) signal amplification One 4-mm thick section was selected...patients treated with radical prostatectomy by using bDNA assay as described in Materials and Methods. Consecutive tissue slides from whole-mounted FFPE

  16. Radon induced background processes in the KATRIN pre-spectrometer

    NASA Astrophysics Data System (ADS)

    Fränkle, F. M.; Bornschein, L.; Drexlin, G.; Glück, F.; Görhardt, S.; Käfer, W.; Mertens, S.; Wandkowsky, N.; Wolf, J.

    2011-10-01

    The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale tritium β-decay experiment to determine the effective electron anti-neutrino mass by investigating the kinematics of tritium β-decay with a sensitivity of 200 meV/c 2 using the MAC-E filter technique. In order to reach this sensitivity, a low background level of 10 -2 counts per second (cps) is required. This paper describes how the decay of radon in a MAC-E filter generates background events, based on measurements performed at the KATRIN pre-spectrometer test setup. Radon (Rn) atoms, which emanate from materials inside the vacuum region of the KATRIN spectrometers, are able to penetrate deep into the magnetic flux tube so that the α-decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn α-decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. While low-energy electrons (<100 eV) directly contribute to the background in the signal region, higher energy electrons can be stored magnetically inside the volume of the spectrometer. Depending on their initial energy, they are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules and, since the detector is not able to distinguish these secondary electrons from the signal electrons, an increased background rate over an extended period of time is generated.

  17. Properties of 83mKr conversion electrons and their use in the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Vénos, D.; Sentkerestiová, J.; Dragoun, O.; Slezák, M.; Ryšavý, M.; Špalek, A.

    2018-02-01

    The gaseous 83mKr will be used as a source of monoenergetic conversion electrons for systematic studies and calibration of the energy scale in the KArlsruhe TRItium Neutrino experiment (KATRIN). Using all existing experimental data the adopted values of the electron binding energies for free krypton were established and the basic conversion electron properties in 83mKr decay were compiled. Modes of the measurements with gaseous 83mKr were suggested for KATRIN.

  18. ERG induces epigenetic activation of Tudor domain-containing protein 1 (TDRD1) in ERG rearrangement-positive prostate cancer.

    PubMed

    Kacprzyk, Lukasz A; Laible, Mark; Andrasiuk, Tatjana; Brase, Jan C; Börno, Stefan T; Fälth, Maria; Kuner, Ruprecht; Lehrach, Hans; Schweiger, Michal R; Sültmann, Holger

    2013-01-01

    Overexpression of ERG transcription factor due to genomic ERG-rearrangements defines a separate molecular subtype of prostate tumors. One of the consequences of ERG accumulation is modulation of the cell's gene expression profile. Tudor domain-containing protein 1 gene (TDRD1) was reported to be differentially expressed between TMPRSS2:ERG-negative and TMPRSS2:ERG-positive prostate cancer. The aim of our study was to provide a mechanistic explanation for the transcriptional activation of TDRD1 in ERG rearrangement-positive prostate tumors. Gene expression measurements by real-time quantitative PCR revealed a remarkable co-expression of TDRD1 and ERG (r(2) = 0.77) but not ETV1 (r(2)<0.01) in human prostate cancer in vivo. DNA methylation analysis by MeDIP-Seq and bisulfite sequencing showed that TDRD1 expression is inversely correlated with DNA methylation at the TDRD1 promoter in vitro and in vivo (ρ = -0.57). Accordingly, demethylation of the TDRD1 promoter in TMPRSS2:ERG-negative prostate cancer cells by DNA methyltransferase inhibitors resulted in TDRD1 induction. By manipulation of ERG dosage through gene silencing and forced expression we show that ERG governs loss of DNA methylation at the TDRD1 promoter-associated CpG island, leading to TDRD1 overexpression. We demonstrate that ERG is capable of disrupting a tissue-specific DNA methylation pattern at the TDRD1 promoter. As a result, TDRD1 becomes transcriptionally activated in TMPRSS2:ERG-positive prostate cancer. Given the prevalence of ERG fusions, TDRD1 overexpression is a common alteration in human prostate cancer which may be exploited for diagnostic or therapeutic procedures.

  19. Reconstitution of the ERG Gene Expression Network Reveals New Biomarkers and Therapeutic Targets in ERG Positive Prostate Tumors

    PubMed Central

    Dubovenko, Alexey; Serebryiskaya, Tatiana; Nikolsky, Yuri; Nikolskaya, Tatiana; Perlina, Ally; JeBailey, Lellean; Bureeva, Svetlana; Katta, Shilpa; Srivastava, Shiv; Dobi, Albert; Khasanova, Tatiana

    2015-01-01

    Background: Despite a growing number of studies evaluating cancer of prostate (CaP) specific gene alterations, oncogenic activation of the ETS Related Gene (ERG) by gene fusions remains the most validated cancer gene alteration in CaP. Prevalent gene fusions have been described between the ERG gene and promoter upstream sequences of androgen-inducible genes, predominantly TMPRSS2 (transmembrane protease serine 2). Despite the extensive evaluations of ERG genomic rearrangements, fusion transcripts and the ERG oncoprotein, the prognostic value of ERG remains to be better understood. Using gene expression dataset from matched prostate tumor and normal epithelial cells from an 80 GeneChip experiment examining 40 tumors and their matching normal pairs in 40 patients with known ERG status, we conducted a cancer signaling-focused functional analysis of prostatic carcinoma representing moderate and aggressive cancers stratified by ERG expression. Results: In the present study of matched pairs of laser capture microdissected normal epithelial cells and well-to-moderately differentiated tumor epithelial cells with known ERG gene expression status from 20 patients with localized prostate cancer, we have discovered novel ERG associated biochemical networks. Conclusions: Using causal network reconstruction methods, we have identified three major signaling pathways related to MAPK/PI3K cascade that may indeed contribute synergistically to the ERG dependent tumor development. Moreover, the key components of these pathways have potential as biomarkers and therapeutic target for ERG positive prostate tumors. PMID:26000039

  20. Electron line shape and transmission function of the KATRIN monitor spectrometer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Slezák, M.

    Knowledge of the neutrino mass is of particular interest in modern neutrino physics. Besides the neutrinoless double beta decay and cosmological observation information about the neutrino mass is obtained from single beta decay by observing the shape of the electron spectrum near the endpoint. The KATRIN β decay experiment aims to push the limit on the effective electron antineutrino mass down to 0.2 eV/c{sup 2}. To reach this sensitivity several systematic effects have to be under control. One of them is the fluctuations of the absolute energy scale, which therefore has to be continuously monitored at very high precision. Thismore » paper shortly describes KATRIN, the technique for continuous monitoring of the absolute energy scale and recent improvements in analysis of the monitoring data.« less

  1. Indexing molecules for their hERG liability.

    PubMed

    Rayan, Anwar; Falah, Mizied; Raiyn, Jamal; Da'adoosh, Beny; Kadan, Sleman; Zaid, Hilal; Goldblum, Amiram

    2013-07-01

    The human Ether-a-go-go-Related-Gene (hERG) potassium (K(+)) channel is liable to drug-inducing blockage that prolongs the QT interval of the cardiac action potential, triggers arrhythmia and possibly causes sudden cardiac death. Early prediction of drug liability to hERG K(+) channel is therefore highly important and preferably obligatory at earlier stages of any drug discovery process. In vitro assessment of drug binding affinity to hERG K(+) channel involves substantial expenses, time, and labor; and therefore computational models for predicting liabilities of drug candidates for hERG toxicity is of much importance. In the present study, we apply the Iterative Stochastic Elimination (ISE) algorithm to construct a large number of rule-based models (filters) and exploit their combination for developing the concept of hERG Toxicity Index (ETI). ETI estimates the molecular risk to be a blocker of hERG potassium channel. The area under the curve (AUC) of the attained model is 0.94. The averaged ETI of hERG binders, drugs from CMC, clinical-MDDR, endogenous molecules, ACD and ZINC, were found to be 9.17, 2.53, 3.3, -1.98, -2.49 and -3.86 respectively. Applying the proposed hERG Toxicity Index Model on external test set composed of more than 1300 hERG blockers picked from chEMBL shows excellent performance (Matthews Correlation Coefficient of 0.89). The proposed strategy could be implemented for the evaluation of chemicals in the hit/lead optimization stages of the drug discovery process, improve the selection of drug candidates as well as the development of safe pharmaceutical products. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  2. Escitalopram block of hERG potassium channels.

    PubMed

    Chae, Yun Ju; Jeon, Ji Hyun; Lee, Hong Joon; Kim, In-Beom; Choi, Jin-Sung; Sung, Ki-Wug; Hahn, Sang June

    2014-01-01

    Escitalopram, a selective serotonin reuptake inhibitor, is the pharmacologically active S-enantiomer of the racemic mixture of RS-citalopram and is widely used in the treatment of depression. The effects of escitalopram and citalopram on the human ether-a-go-go-related gene (hERG) channels expressed in human embryonic kidney cells were investigated using voltage-clamp and Western blot analyses. Both drugs blocked hERG currents in a concentration-dependent manner with an IC50 value of 2.6 μM for escitalopram and an IC50 value of 3.2 μM for citalopram. The blocking of hERG by escitalopram was voltage-dependent, with a steep increase across the voltage range of channel activation. However, voltage independence was observed over the full range of activation. The blocking by escitalopram was frequency dependent. A rapid application of escitalopram induced a rapid and reversible blocking of the tail current of hERG. The extent of the blocking by escitalopram during the depolarizing pulse was less than that during the repolarizing pulse, suggesting that escitalopram has a high affinity for the open state of the hERG channel, with a relatively lower affinity for the inactivated state. Both escitalopram and citalopram produced a reduction of hERG channel protein trafficking to the plasma membrane but did not affect the short-term internalization of the hERG channel. These results suggest that escitalopram blocked hERG currents at a supratherapeutic concentration and that it did so by preferentially binding to both the open and the inactivated states of the channels and by inhibiting the trafficking of hERG channel protein to the plasma membrane.

  3. Tests of by-pass diodes at cryogenic temperatures for the KATRIN magnets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gil, W.; Bolz, H.; Jansen, A.

    The Karlsruhe Tritium Neutrino experiment (KATRIN) requires a series of superconducting solenoid magnets for guiding beta-electrons from the source to the detector. By-pass diodes will operate at liquid helium temperatures to protect the superconducting magnets and bus bars in case of quenches. The operation conditions of the by-pass diodes depend on the different magnet systems of KATRIN. Therefore, different diode stacks are designed with adequate copper heat sinks assuming adiabatic conditions. The by-pass diode stacks have been submitted to cold tests both at liquid nitrogen and liquid helium temperatures for checking operation conditions. This report presents the test set upmore » and first results of the diode characteristics at 300 K and 77 K, as well as of endurance tests of the diode stacks at constant current load at 77 K and 4.2 K.« less

  4. Gaseous 83mKr generator for KATRIN

    NASA Astrophysics Data System (ADS)

    Sentkerestiová, J.; Dragoun, O.; Lebeda, O.; Ryšavý, M.; Sturm, M.; Vénos, D.

    2018-04-01

    Monoenergetic conversion electrons from the 83mKrKr isomeric state have been proven to be useful in the calibration of several tritium neutrino mass and dark matter experiments. In this paper the design and characteristics of the gaseous 83mKrKr generator, including the 83Rb/83mKrKr source behavior in tritium, for the KATRIN experiment are presented. Using Si(Li) and silicon drift detectors (SDD) detectors, the half-life of the 83mKrKr isomeric state was measured to be 1.8620 ± 0.0019 h.

  5. ERG oncoprotein expression in prostate carcinoma patients of different ethnicities.

    PubMed

    Kelly, Gregory M; Kong, Yink Heay; Dobi, Albert; Srivastava, Shiv; Sesterhenn, Isabell A; Pathmanathan, Rajadurai; Tan, Hui Meng; Tan, Shyh-Han; Cheong, Sok Ching

    2015-01-01

    Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 ( TMPRSS2 ) -ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the

  6. ERG oncoprotein expression in prostate carcinoma patients of different ethnicities

    PubMed Central

    KELLY, GREGORY M.; KONG, YINK HEAY; DOBI, ALBERT; SRIVASTAVA, SHIV; SESTERHENN, ISABELL A.; PATHMANATHAN, RAJADURAI; TAN, HUI MENG; TAN, SHYH-HAN; CHEONG, SOK CHING

    2015-01-01

    Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology

  7. Multifocal ERG findings in carriers of X-linked retinoschisis

    PubMed Central

    Kim, Linda S.; Seiple, William; Szlyk, Janet P.

    2006-01-01

    Purpose To determine whether retinal dysfunction in obligate carriers of X-linked retinoschisis (XLRS) could be observed in local electroretinographic responses obtained with the multifocal electroretinogram (mfERG). Methods Nine obligate carriers of XLRS (mean age, 46.2 years) were examined for the study. Examination of each carrier included an ocular examination and mfERG testing. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40° in diameter. The amplitudes and implicit times in each location for the mfERG were compared with the corresponding values determined for a group of 34 normally-sighted, age-similar control subjects. Results Mapping of 103 local electroretinographic response amplitudes and implicit times within a central 40° area with the mfERG showed regions of reduced mfERG amplitudes and delayed implicit times in two of nine carriers. Conclusions The mfERG demonstrated areas of retinal dysfunction in two carriers of XLRS. When present, retinal dysfunction was evident in the presence of a normal-appearing fundus. Multifocal ERG testing can be useful for identifying some carriers of XLRS. PMID:17180613

  8. hERG Blockade by Iboga Alkaloids.

    PubMed

    Alper, Kenneth; Bai, Rong; Liu, Nian; Fowler, Steven J; Huang, Xi-Ping; Priori, Silvia G; Ruan, Yanfei

    2016-01-01

    The iboga alkaloids are a class of naturally occurring and synthetic compounds, some of which modify drug self-administration and withdrawal in humans and preclinical models. Ibogaine, the prototypic iboga alkaloid that is utilized clinically to treat addictions, has been associated with QT prolongation, torsades de pointes and fatalities. hERG blockade as IKr was measured using the whole-cell patch clamp technique in HEK 293 cells. This yielded the following IC50 values: ibogaine manufactured by semisynthesis via voacangine (4.09 ± 0.69 µM) or by extraction from T. iboga (3.53 ± 0.16 µM); ibogaine's principal metabolite noribogaine (2.86 ± 0.68 µM); and voacangine (2.25 ± 0.34 µM). In contrast, the IC50 of 18-methoxycoronaridine, a product of rational synthesis and current focus of drug development was >50 µM. hERG blockade was voltage dependent for all of the compounds, consistent with low-affinity blockade. hERG channel binding affinities (K i) for the entire set of compounds, including 18-MC, ranged from 0.71 to 3.89 µM, suggesting that 18-MC binds to the hERG channel with affinity similar to the other compounds, but the interaction produces substantially less hERG blockade. In view of the extended half-life of noribogaine, these results may relate to observations of persistent QT prolongation and cardiac arrhythmia at delayed intervals of days following ibogaine ingestion. The apparent structure-activity relationships regarding positions of substitutions on the ibogamine skeleton suggest that the iboga alkaloids might provide an informative paradigm for investigation of the structural biology of the hERG channel.

  9. Neutrinos secretly converting to lighter particles to please both KATRIN and the cosmos

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farzan, Yasaman; Hannestad, Steen, E-mail: yasaman@theory.ipm.ac.ir, E-mail: sth@phys.au.dk

    Within the framework of the Standard Model of particle physics and standard cosmology, observations of the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO) set stringent bounds on the sum of the masses of neutrinos. If these bounds are satisfied, the upcoming KATRIN experiment which is designed to probe neutrino mass down to ∼ 0.2 eV will observe only a null signal. We show that the bounds can be relaxed by introducing new interactions for the massive active neutrinos, making neutrino masses in the range observable by KATRIN compatible with cosmological bounds. Within this scenario, neutrinos convert to new stablemore » light particles by resonant production of intermediate states around a temperature of T∼ keV in the early Universe, leading to a much less pronounced suppression of density fluctuations compared to the standard model.« less

  10. Deletion of the Candida glabrata ERG3 and ERG11 genes: effect on cell viability, cell growth, sterol composition, and antifungal susceptibility.

    PubMed Central

    Geber, A; Hitchcock, C A; Swartz, J E; Pullen, F S; Marsden, K E; Kwon-Chung, K J; Bennett, J E

    1995-01-01

    We have cloned and sequenced the structural genes encoding the delta 5,6 sterol desaturase (ERG3 gene) and the 14 alpha-methyl sterol demethylase (ERG11 gene) from Candida glabrata L5 (leu2). Single and double mutants of these genes were created by gene deletion. The phenotypes of these mutants, including sterol profiles, aerobic viabilities, antifungal susceptibilities, and generation times, were studied. Strain L5D (erg3 delta::LEU2) accumulated mainly ergosta-7,22-dien-3 beta-ol, was aerobically viable, and remained susceptible to antifungal agents but had a slower generation time than its parent strain. L5LUD (LEU2 erg11 delta::URA3) strains required medium supplemented with ergosterol and an anaerobic environment for growth. A spontaneous aerobically viable mutant, L5LUD40R (LEU erg11 delta::URA3), obtained from L5LUD (LEU2 erg11 delta::URA3), was found to accumulate lanosterol and obtusifoliol, was resistant to azole antifungal agents, demonstrated some increase in resistance to amphotericin B, and exhibited a 1.86-fold increase in generation time in comparison with L5 (leu2). The double-deletion mutant L5DUD61 (erg3 delta::LEU2 erg11 delta::URA3) was aerobically viable, produced mainly 14 alpha-methyl fecosterol, and had the same antifungal susceptibility pattern as L5LUD40R (LEU2 erg11 delta::URA3), and its generation time was threefold greater than that of L5 (leu2). Northern (RNA) analysis revealed that the single-deletion mutants had a marked increase in message for the undeleted ERG3 and ERG11 genes. These results indicate that differences in antifungal susceptibilities and the restoration of aerobic viability exist between the C. glabrata ergosterol mutants created in this study and those sterol mutants with similar genetic lesions previously reported for Saccharomyces cerevisiae. PMID:8593007

  11. Commissioning of the vacuum system of the KATRIN Main Spectrometer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Arenz, M.; Babutzka, M.; Bahr, M.

    The KATRIN experiment will probe the neutrino mass by measuring the β-electron energy spectrum near the endpoint of tritium β-decay. We performed an integral energy analysis by an electro-static spectrometer (``Main Spectrometer''), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m 3, and a complex inner electrode system with about 120 000 individual parts. The strong magnetic field that guides the β-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. Furthermore, a system consisting of 6 turbo-molecular pumps andmore » 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300 °C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10 -11 mbar range. We demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.« less

  12. Commissioning of the vacuum system of the KATRIN Main Spectrometer

    DOE PAGES

    Arenz, M.; Babutzka, M.; Bahr, M.; ...

    2016-04-07

    The KATRIN experiment will probe the neutrino mass by measuring the β-electron energy spectrum near the endpoint of tritium β-decay. We performed an integral energy analysis by an electro-static spectrometer (``Main Spectrometer''), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m 3, and a complex inner electrode system with about 120 000 individual parts. The strong magnetic field that guides the β-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. Furthermore, a system consisting of 6 turbo-molecular pumps andmore » 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300 °C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10 -11 mbar range. We demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.« less

  13. Reduced Erg Dosage Impairs Survival of Hematopoietic Stem and Progenitor Cells.

    PubMed

    Xie, Ying; Koch, Mia Lee; Zhang, Xin; Hamblen, Melanie J; Godinho, Frank J; Fujiwara, Yuko; Xie, Huafeng; Klusmann, Jan-Henning; Orkin, Stuart H; Li, Zhe

    2017-07-01

    ERG, an ETS family transcription factor frequently overexpressed in human leukemia, has been implicated as a key regulator of hematopoietic stem cells. However, how ERG controls normal hematopoiesis, particularly at the stem and progenitor cell level, and how it contributes to leukemogenesis remain incompletely understood. Using homologous recombination, we generated an Erg knockdown allele (Erg kd ) in which Erg expression can be conditionally restored by Cre recombinase. Erg kd/kd animals die at E10.5-E11.5 due to defects in endothelial and hematopoietic cells, but can be completely rescued by Tie2-Cre-mediated restoration of Erg in these cells. In Erg kd/+ mice, ∼40% reduction in Erg dosage perturbs both fetal liver and bone marrow hematopoiesis by reducing the numbers of Lin - Sca-1 + c-Kit + (LSK) hematopoietic stem and progenitor cells (HSPCs) and megakaryocytic progenitors. By genetic mosaic analysis, we find that Erg-restored HSPCs outcompete Erg kd/+ HSPCs for contribution to adult hematopoiesis in vivo. This defect is in part due to increased apoptosis of HSPCs with reduced Erg dosage, a phenotype that becomes more drastic during 5-FU-induced stress hematopoiesis. Expression analysis reveals that reduced Erg expression leads to changes in expression of a subset of ERG target genes involved in regulating survival of HSPCs, including increased expression of a pro-apoptotic regulator Bcl2l11 (Bim) and reduced expression of Jun. Collectively, our data demonstrate that ERG controls survival of HSPCs, a property that may be used by leukemic cells. Stem Cells 2017;35:1773-1785. © 2017 AlphaMed Press.

  14. DEREGULATION OF DUX4 AND ERG IN ACUTE LYMPHOBLASTIC LEUKEMIA

    PubMed Central

    Zhang, Jinghui; McCastlain, Kelly; Yoshihara, Hiroki; Xu, Beisi; Chang, Yunchao; Churchman, Michelle L.; Wu, Gang; Li, Yongjin; Wei, Lei; Iacobucci, Ilaria; Liu, Yu; Qu, Chunxu; Wen, Ji; Edmonson, Michael; Payne-Turner, Debbie; Kaufmann, Kerstin B.; Takayanagi, Shin-ichiro; Wienholds, Erno; Waanders, Esmé; Ntziachristos, Panagiotis; Bakogianni, Sofia; Wang, Jingjing; Aifantis, Iannis; Roberts, Kathryn G.; Ma, Jing; Song, Guangchun; Easton, John; Mulder, Heather L.; Chen, Xiang; Newman, Scott; Ma, Xiaotu; Rusch, Michael; Gupta, Pankaj; Boggs, Kristy; Vadodaria, Bhavin; Dalton, James; Liu, Yanling; Valentine, Marcus L; Ding, Li; Lu, Charles; Fulton, Robert S.; Fulton, Lucinda; Tabib, Yashodhan; Ochoa, Kerri; Devidas, Meenakshi; Pei, Deqing; Cheng, Cheng; Yang, Jun; Evans, William E.; Relling, Mary V.; Pui, Ching-Hon; Jeha, Sima; Harvey, Richard C.; Chen, I-Ming L; Willman, Cheryl L.; Marcucci, Guido; Bloomfield, Clara D.; Kohlschmidt, Jessica; Mrózek, Krzysztof; Paietta, Elisabeth; Tallman, Martin S.; Stock, Wendy; Foster, Matthew C.; Racevskis, Janis; Rowe, Jacob M.; Luger, Selina; Kornblau, Steven M.; Shurtleff, Sheila A; Raimondi, Susana C.; Mardis, Elaine R.; Wilson, Richard K.; Dick, John E.; Hunger, Stephen P; Loh, Mignon L.; Downing, James R.; Mullighan, Charles G.

    2016-01-01

    Chromosomal rearrangements deregulating hematopoietic transcription factors are common in acute lymphoblastic leukemia (ALL).1,2 Here, we show that deregulation of the homeobox transcription factor gene DUX4 and the ETS transcription factor gene ERG are hallmarks of a subtype of B-progenitor ALL that comprises up to 7% of B-ALL. DUX4 rearrangement and overexpression was present in all cases, and was accompanied by transcriptional deregulation of ERG, expression of a novel ERG isoform, ERGalt, and frequent ERG deletion. ERGalt utilizes a non-canonical first exon whose transcription was initiated by DUX4 binding. ERGalt retains the DNA-binding and transactivating domains of ERG, but inhibits wild-type ERG transcriptional activity and is transforming. These results illustrate a unique paradigm of transcription factor deregulation in leukemia, in which DUX4 deregulation results in loss-of-function of ERG, either by deletion or induction of expression of an isoform that is a dominant negative inhibitor of wild type ERG function. PMID:27776115

  15. The ubiquitin ligase TRIM25 targets ERG for degradation in prostate cancer.

    PubMed

    Wang, Shan; Kollipara, Rahul K; Humphries, Caroline G; Ma, Shi-Hong; Hutchinson, Ryan; Li, Rui; Siddiqui, Javed; Tomlins, Scott A; Raj, Ganesh V; Kittler, Ralf

    2016-10-04

    Ets related gene (ERG) is a transcription factor that is overexpressed in 40% of prostate tumors due to a gene fusion between ERG and TMPRSS2. Because ERG functions as a driver of prostate carcinogenesis, understanding the mechanisms that influence its turnover may provide new molecular handles to target the protein. Previously, we found that ERG undergoes ubiquitination and then is deubiquitinated by USP9X in prostate cancer cells to prevent its proteasomal degradation. Here, we identify Tripartite motif-containing protein 25 (TRIM25) as the E3 ubiquitin ligase that ubiquitinates the protein prior to its degradation. TRIM25 binds full-length ERG, and it also binds the N-terminally truncated variants of ERG that are expressed in tumors with TMPRSS2-ERG fusions. We demonstrate that TRIM25 polyubiquitinates ERG in vitro and that inactivation of TRIM25 resulted in reduced polyubiquitination and stabilization of ERG. TRIM25 mRNA and protein expression was increased in ERG rearrangement-positive prostate cancer specimens, and we provide evidence that ERG upregulates TRIM25 expression. Thus, overexpression of ERG in prostate cancer may cause an increase in TRIM25 activity, which is mitigated by the expression of the deubiquitinase USP9X, which is required to stabilize ERG.

  16. The ubiquitin ligase TRIM25 targets ERG for degradation in prostate cancer

    PubMed Central

    Wang, Shan; Kollipara, Rahul K.; Humphries, Caroline G.; Ma, Shi-Hong; Hutchinson, Ryan; Li, Rui; Siddiqui, Javed; Tomlins, Scott A.; Raj, Ganesh V.; Kittler, Ralf

    2016-01-01

    Ets related gene (ERG) is a transcription factor that is overexpressed in 40% of prostate tumors due to a gene fusion between ERG and TMPRSS2. Because ERG functions as a driver of prostate carcinogenesis, understanding the mechanisms that influence its turnover may provide new molecular handles to target the protein. Previously, we found that ERG undergoes ubiquitination and then is deubiquitinated by USP9X in prostate cancer cells to prevent its proteasomal degradation. Here, we identify Tripartite motif-containing protein 25 (TRIM25) as the E3 ubiquitin ligase that ubiquitinates the protein prior to its degradation. TRIM25 binds full-length ERG, and it also binds the N-terminally truncated variants of ERG that are expressed in tumors with TMPRSS2-ERG fusions. We demonstrate that TRIM25 polyubiquitinates ERG in vitro and that inactivation of TRIM25 resulted in reduced polyubiquitination and stabilization of ERG. TRIM25 mRNA and protein expression was increased in ERG rearrangement-positive prostate cancer specimens, and we provide evidence that ERG upregulates TRIM25 expression. Thus, overexpression of ERG in prostate cancer may cause an increase in TRIM25 activity, which is mitigated by the expression of the deubiquitinase USP9X, which is required to stabilize ERG. PMID:27626314

  17. Probability Based hERG Blocker Classifiers.

    PubMed

    Wang, Zhi; Mussa, Hamse Y; Lowe, Robert; Glen, Robert C; Yan, Aixia

    2012-09-01

    The US Food and Drug Administration (FDA) require in vitro human ether-a-go-go related (hERG) ion channel affinity tests for all drug candidates prior to clinical trials. In this study, probabilistic-based methods were employed to develop prediction models on hERG inhibition prediction, which are different from traditional QSAR models that are mainly based on supervised 'hard point' (HP) classification approaches giving 'yes/no' answers. The obtained models can 'ascertain' whether or not a given set of compounds can block hERG ion channels. The results presented indicate that the proposed probabilistic-based method can be a valuable tool for ranking compounds with respect to their potential cardio-toxicity and will be promising for other toxic property predictions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Low Frequency of the ERG Oncogene Alterations in Prostate Cancer Patients from India.

    PubMed

    Rawal, Sudhir; Young, Denise; Williams, Molly; Colombo, Monica; Krishnappa, Raghunath; Petrovics, Gyorgy; McLeod, David G; Srivastava, Shiv; Sesterhenn, Isabell A

    2013-01-01

    ERG oncogene fusions (predominantly TMPRSS2-ERG) represent the most common (50-70% frequency) and validated prostate cancer (CaP) genome alteration in the Western countries. A common TMPRSS2-ERG fusion type leads to the androgen dependent tumor cell specific expression of the TMPRSS2-ERG fusion transcript and amino terminally truncated ERG oncoprotein. CaP prevalence and aggressiveness, as well as genomic alterations vary in different geographic locations in the world. Recent studies from our group highlighted significantly lower frequency of ERG alterations in prostate index tumors of African American men (~30%) in comparison to Caucasian Americans (~60%). Further, much lower frequencies (10 -25%) of ERG alterations have been reported in studies from China and Japan. There is no study on ERG alterations in CaP patients from India, representing a significant portion of the world male population. This study focuses on the frequency of ERG oncoprotein expression in CaP patients from India. De-identified formalin-fixed paraffin-embedded (FFPE) specimens from radical prostatectomy (RP) specimens of 51 patients from the Rajiv Gandhi Cancer Institute and Research Centre (RGCI), New Delhi, India, were analyzed for ERG alterations. The ERG oncoprotein expression as a surrogate of ERG gene fusions was analyzed by using a highly specific ERG monoclonal antibody (9FY). TMPRSS2-ERG fusion was assessed by fluorescent in situ hybridization (FISH) assays using the break-apart ERG probes. Specimens reflecting prior hormonal treatment, or lacking any tumor content, were excluded from the analyses. Of the thirty evaluable specimens, ERG positive tumors were present in 8 cases (27%) and one tumor specimen exhibited rare ERG positive cells. None of the benign glands were positive for ERG supporting previous studies showing complete specificity of the ERG oncoprotein for detection of tumors cells in prostate. Frequency of ERG oncoprotein expression is much lower in CaP patients from

  19. Natural products modulating the hERG channel: heartaches and hope.

    PubMed

    Kratz, Jadel M; Grienke, Ulrike; Scheel, Olaf; Mann, Stefan A; Rollinger, Judith M

    2017-08-02

    Covering: 1996-December 2016The human Ether-à-go-go Related Gene (hERG) channel is a voltage-gated potassium channel playing an essential role in the normal electrical activity in the heart. It is involved in the repolarization and termination of action potentials in excitable cardiac cells. Mutations in the hERG gene and hERG channel blockage by small molecules are associated with increased risk of fatal arrhythmias. Several drugs have been withdrawn from the market due to hERG channel-related cardiotoxicity. Moreover, as a result of its notorious ligand promiscuity, this ion channel has emerged as an important antitarget in early drug discovery and development. Surprisingly, the hERG channel blocking profile of natural compounds present in frequently consumed botanicals (i.e. dietary supplements, spices, and herbal medicinal products) is not routinely assessed. This comprehensive review will address these issues and provide a critical compilation of hERG channel data for isolated natural products and extracts over the past two decades (1996-2016). In addition, the review will provide (i) a solid basis for the molecular understanding of the physiological functions of the hERG channel, (ii) the translational potential of in vitro/in vivo results to cardiotoxicity in humans, (iii) approaches for the identification of hERG channel blockers from natural sources, (iv) future perspectives for cardiac safety guidelines and their applications within phytopharmaceuticals and dietary supplements, and (v) novel applications of hERG channel modulation (e.g. as a drug target).

  20. hERG trafficking inhibition in drug-induced lethal cardiac arrhythmia.

    PubMed

    Nogawa, Hisashi; Kawai, Tomoyuki

    2014-10-15

    Acquired long QT syndrome induced by non-cardiovascular drugs can cause lethal cardiac arrhythmia called torsades de points and is a significant problem in drug development. The prolongation of QT interval and cardiac action potential duration are mainly due to reduced physiological function of the rapidly activating voltage-dependent potassium channels encoded by human ether-a-go-go-related gene (hERG). Structurally diverse groups of drugs are known to directly inhibit hERG channel conductance. Therefore, the ability of acute hERG inhibition is routinely assessed at the preclinical stages in pharmaceutical testing. Recent findings indicated that chronic treatment with various drugs not only inhibits hERG channels but also decreases hERG channel expression in the plasma membrane of cardiomyocytes, which has become another concern in safety pharmacology. The mechanisms involve the disruption of hERG trafficking to the surface membrane or the acceleration of hERG protein degradation. From this perspective, we present a brief overview of mechanisms of drug-induced trafficking inhibition and pathological regulation. Understanding of drug-induced hERG trafficking inhibition may provide new strategies for predicting drug-induced QT prolongation and lethal cardiac arrhythmia in pharmaceutical drug development. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. The Role ERG and CXCR4 in Prostate Cancer Progression

    DTIC Science & Technology

    2011-06-01

    axis functions in PC progression to enhance invasion and metastasis. To address the regulation of CXCR4 expression, we identified several putative ERG...interaction between ERG factor and CXCR4 gene promoter and link these activities with TMPRSS2-ERG translocations and enhanced metastasis of tumor cells via...and increased VCaP nuclear extract protein in assay enhanced the intensity of bands (Figure 1D). Inclusion of anti-ERG antibodies super shifted

  2. [The reproducibility of multifocal ERG recordings].

    PubMed

    Meigen, T; Friedrich, A

    2002-09-01

    Multifocal electroretinogram recordings (mfERG) can be used to detect a local dysfunction of the retina. In this study we tested both the intrasessional and inter-sessional reproducibility of mfERG amplitudes. MfERGs from 6 eyes of 6 normal subjects were recorded on two different days using DTL electrodes. The relative coefficient of variation ( RCV) was used to quantify the amplitude reproducibility. We tested the effect of (a) session (inter- vs. intrasessional), (b) recording duration (7.3 vs. 3.6 min), (c) trace type (hexagon traces vs. ring averages), and (d) amplitude definition (peak-trough analysis vs. scalar product) on RCV. RCV was 6.5+/-0.4% (Mean+/-SEM, n=96) when averaged across all recording conditions and all subjects. The ANOVA showed a significant difference ( p=0.018) between hexagon traces and ring averages. Another significant effect ( p=0.016) occurred for the interaction of (a) and (b). MfERGs can be recorded with a high degree of reproducibility even for short recording durations and single hexagon traces. As the factor (a) did not show a significant effect, the new placement of the DTL electrode in the second session does not necessarily increase the retest variability compared to a second recording within the same session.

  3. Calibration of high voltages at the ppm level by the difference of ^{83{m}}Kr conversion electron lines at the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Arenz, M.; Baek, W.-J.; Beck, M.; Beglarian, A.; Behrens, J.; Bergmann, T.; Berlev, A.; Besserer, U.; Blaum, K.; Bode, T.; Bornschein, B.; Bornschein, L.; Brunst, T.; Buzinsky, N.; Chilingaryan, S.; Choi, W. Q.; Deffert, M.; Doe, P. J.; Dragoun, O.; Drexlin, G.; Dyba, S.; Edzards, F.; Eitel, K.; Ellinger, E.; Engel, R.; Enomoto, S.; Erhard, M.; Eversheim, D.; Fedkevych, M.; Fischer, S.; Formaggio, J. A.; Fränkle, F. M.; Franklin, G. B.; Friedel, F.; Fulst, A.; Gil, W.; Glück, F.; Ureña, A. Gonzalez; Grohmann, S.; Grössle, R.; Gumbsheimer, R.; Hackenjos, M.; Hannen, V.; Harms, F.; Haußmann, N.; Heizmann, F.; Helbing, K.; Herz, W.; Hickford, S.; Hilk, D.; Hillesheimer, D.; Howe, M. A.; Huber, A.; Jansen, A.; Kellerer, J.; Kernert, N.; Kippenbrock, L.; Kleesiek, M.; Klein, M.; Kopmann, A.; Korzeczek, M.; Kovalík, A.; Krasch, B.; Kraus, M.; Kuckert, L.; Lasserre, T.; Lebeda, O.; Letnev, J.; Lokhov, A.; Machatschek, M.; Marsteller, A.; Martin, E. L.; Mertens, S.; Mirz, S.; Monreal, B.; Neumann, H.; Niemes, S.; Off, A.; Osipowicz, A.; Otten, E.; Parno, D. S.; Pollithy, A.; Poon, A. W. P.; Priester, F.; Ranitzsch, P. C.-O.; Rest, O.; Robertson, R. G. H.; Roccati, F.; Rodenbeck, C.; Röllig, M.; Röttele, C.; Ryšavý, M.; Sack, R.; Saenz, A.; Schimpf, L.; Schlösser, K.; Schlösser, M.; Schönung, K.; Schrank, M.; Seitz-Moskaliuk, H.; Sentkerestiová, J.; Sibille, V.; Slezák, M.; Steidl, M.; Steinbrink, N.; Sturm, M.; Suchopar, M.; Suesser, M.; Telle, H. H.; Thorne, L. A.; Thümmler, T.; Titov, N.; Tkachev, I.; Trost, N.; Valerius, K.; Vénos, D.; Vianden, R.; Hernández, A. P. Vizcaya; Weber, M.; Weinheimer, C.; Weiss, C.; Welte, S.; Wendel, J.; Wilkerson, J. F.; Wolf, J.; Wüstling, S.; Zadoroghny, S.

    2018-05-01

    The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at - 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two ^{83{m}}Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor M=1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.

  4. ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis

    PubMed Central

    Luna-Tapia, Arturo; Peters, Brian M.; Eberle, Karen E.; Kerns, Morgan E.; Foster, Timothy P.; Marrero, Luis; Noverr, Mairi C.; Fidel, Paul L.

    2015-01-01

    Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed. PMID:26231054

  5. Mechanism and pharmacological rescue of berberine-induced hERG channel deficiency

    PubMed Central

    Yan, Meng; Zhang, Kaiping; Shi, Yanhui; Feng, Lifang; Lv, Lin; Li, Baoxin

    2015-01-01

    Berberine (BBR), an isoquinoline alkaloid mainly isolated from plants of Berberidaceae family, is extensively used to treat gastrointestinal infections in clinics. It has been reported that BBR can block human ether-a-go-go-related gene (hERG) potassium channel and inhibit its membrane expression. The hERG channel plays crucial role in cardiac repolarization and is the target of diverse proarrhythmic drugs. Dysfunction of hERG channel can cause long QT syndrome. However, the regulatory mechanisms of BBR effects on hERG at cell membrane level remain unknown. This study was designed to investigate in detail how BBR decreased hERG expression on cell surface and further explore its pharmacological rescue strategies. In this study, BBR decreases caveolin-1 expression in a concentration-dependent manner in human embryonic kidney 293 (HEK293) cells stably expressing hERG channel. Knocking down the basal expression of caveolin-1 alleviates BBR-induced hERG reduction. In addition, we found that aromatic tyrosine (Tyr652) and phenylalanine (Phe656) in S6 domain mediate the long-term effect of BBR on hERG by using mutation techniques. Considering both our previous and present work, we propose that BBR reduces hERG membrane stability with multiple mechanisms. Furthermore, we found that fexofenadine and resveratrol shorten action potential duration prolongated by BBR, thus having the potential effects of alleviating the cardiotoxicity of BBR. PMID:26543354

  6. ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis.

    PubMed

    Luna-Tapia, Arturo; Peters, Brian M; Eberle, Karen E; Kerns, Morgan E; Foster, Timothy P; Marrero, Luis; Noverr, Mairi C; Fidel, Paul L; Palmer, Glen E

    2015-10-01

    Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Technical design and commissioning of the KATRIN large-volume air coil system

    NASA Astrophysics Data System (ADS)

    Erhard, M.; Behrens, J.; Bauer, S.; Beglarian, A.; Berendes, R.; Drexlin, G.; Glück, F.; Gumbsheimer, R.; Hergenhan, J.; Leiber, B.; Mertens, S.; Osipowicz, A.; Plischke, P.; Reich, J.; Thümmler, T.; Wandkowsky, N.; Weinheimer, C.; Wüstling, S.

    2018-02-01

    The KATRIN experiment is a next-generation direct neutrino mass experiment with a sensitivity of 0.2 eV (90% C.L.) to the effective mass of the electron neutrino. It measures the tritium β-decay spectrum close to its endpoint with a spectrometer based on the MAC-E filter technique. The β-decay electrons are guided by a magnetic field that operates in the mT range in the central spectrometer volume; it is fine-tuned by a large-volume air coil system surrounding the spectrometer vessel. The purpose of the system is to provide optimal transmission properties for signal electrons and to achieve efficient magnetic shielding against background. In this paper we describe the technical design of the air coil system, including its mechanical and electrical properties. We outline the importance of its versatile operation modes in background investigation and suppression techniques. We compare magnetic field measurements in the inner spectrometer volume during system commissioning with corresponding simulations, which allows to verify the system's functionality in fine-tuning the magnetic field configuration. This is of major importance for a successful neutrino mass measurement at KATRIN.

  8. Intrafocal heterogeneity of ERG protein expression and gene fusion pattern in prostate cancer.

    PubMed

    Suh, Ja Hee; Park, Jeong Hwan; Lee, Cheol; Moon, Kyung Chul

    2017-10-01

    Prostate cancer is considered to be highly heterogeneous, with various morphologic features and biologic behaviors. The TMPRSS2-ERG gene fusion is the most frequently observed genetic aberration in prostate cancer. The aim of this study was to elucidate the intrafocal heterogeneity of ERG gene fusion status. ERG immunohistochemistry (IHC) was performed in samples from 168 prostate cancer patients who had undergone radical prostatectomy, and 40 cases showing ERG-positive IHC staining were selected for tissue microarray (TMA) construction. Two to six representative cores were selected from each tumor focus. In the cases with heterogeneous ERG IHC staining intensity, the areas showing different intensities were separately selected. Using the TMA blocks, IHC and fluorescence in situ hybridization (FISH) were conducted to evaluate the heterogeneity of ERG protein expression and ERG fusion gene patterns, respectively, in a single tumor focus. Heterogeneity of ERG IHC staining was defined as the simultaneous presence of negative and positive cores in the same tumor focus. Heterogeneity of ERG FISH was defined by the presence of cores with positive and negative FISH signals or cores with break-apart and interstitial deletion FISH signals in the same tumor focus. A total of 202 TMA cores were isolated from 40 ERG-positive cases. Of the 202 total cores, 19 were negative for ERG IHC staining, and 46 showed 1+, 52 showed 2+, and 85 showed 3+ ERG staining intensity. Eleven cores were negative for ERG FISH signal, 119 cores showed ERG break-apart FISH signals, and the remaining 72 cores revealed interstitial deletion. Intrafocal heterogeneity of ERG IHC staining was found in 20% (8/40) of cases, and intrafocal heterogeneity of ERG gene fusion pattern was found in 32.5% (13/40) of cases. In summary, this study showed significantly frequent intrafocal heterogeneity of ERG protein expression, gene fusion status and fusion pattern. This heterogeneity can be caused by the development

  9. Autoinhibitory mechanisms of ERG studied by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Lu, Yan; Salsbury, Freddie R.

    2015-01-01

    ERG, an ETS-family transcription factor, acts as a regulator of differentiation of early hematopoietic cells. It contains an autoinhibitory domain, which negatively regulates DNA-binding. The mechanism of autoinhibitory is still illusive. To understand the mechanism, we study the dynamical properties of ERG protein by molecular dynamics simulations. These simulations suggest that DNA binding autoinhibition associates with the internal dynamics of ERG. Specifically, we find that (1), The N-C terminal correlation in the inhibited ERG is larger than that in uninhibited ERG that contributes to the autoinhibition of DNA-binding. (2), DNA-binding changes the property of the N-C terminal correlation from being anti-correlated to correlated, that is, changing the relative direction of the correlated motions and (3), For the Ets-domain specifically, the inhibited and uninhibited forms exhibit essentially the same dynamics, but the binding of the DNA decreases the fluctuation of the Ets-domain. We also find from PCA analysis that the three systems, even with quite different dynamics, do have highly similar free energy surfaces, indicating that they share similar conformations.

  10. Statistical sensitivity on right-handed currents in presence of eV scale sterile neutrinos with KATRIN

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steinbrink, Nicholas M.N.; Weinheimer, Christian; Glück, Ferenc

    The KATRIN experiment aims to determine the absolute neutrino mass by measuring the endpoint region of the tritium β-spectrum. As a large-scale experiment with a sharp energy resolution, high source luminosity and low background it may also be capable of testing certain theories of neutrino interactions beyond the standard model (SM). An example of a non-SM interaction are right-handed currents mediated by right-handed W bosons in the left-right symmetric model (LRSM). In this extension of the SM, an additional SU(2){sub R} symmetry in the high-energy limit is introduced, which naturally includes sterile neutrinos and predicts the seesaw mechanism. In tritiummore » β decay, this leads to an additional term from interference between left- and right-handed interactions, which enhances or suppresses certain regions near the endpoint of the beta spectrum. In this work, the sensitivity of KATRIN to right-handed currents is estimated for the scenario of a light sterile neutrino with a mass of some eV. This analysis has been performed with a Bayesian analysis using Markov Chain Monte Carlo (MCMC). The simulations show that, in principle, KATRIN will be able to set sterile neutrino mass-dependent limits on the interference strength. The sensitivity is significantly increased if the Q value of the β decay can be sufficiently constrained. However, the sensitivity is not high enough to improve current upper limits from right-handed W boson searches at the LHC.« less

  11. Statistical sensitivity on right-handed currents in presence of eV scale sterile neutrinos with KATRIN

    NASA Astrophysics Data System (ADS)

    Steinbrink, Nicholas M. N.; Glück, Ferenc; Heizmann, Florian; Kleesiek, Marco; Valerius, Kathrin; Weinheimer, Christian; Hannestad, Steen

    2017-06-01

    The KATRIN experiment aims to determine the absolute neutrino mass by measuring the endpoint region of the tritium β-spectrum. As a large-scale experiment with a sharp energy resolution, high source luminosity and low background it may also be capable of testing certain theories of neutrino interactions beyond the standard model (SM). An example of a non-SM interaction are right-handed currents mediated by right-handed W bosons in the left-right symmetric model (LRSM). In this extension of the SM, an additional SU(2)R symmetry in the high-energy limit is introduced, which naturally includes sterile neutrinos and predicts the seesaw mechanism. In tritium β decay, this leads to an additional term from interference between left- and right-handed interactions, which enhances or suppresses certain regions near the endpoint of the beta spectrum. In this work, the sensitivity of KATRIN to right-handed currents is estimated for the scenario of a light sterile neutrino with a mass of some eV. This analysis has been performed with a Bayesian analysis using Markov Chain Monte Carlo (MCMC). The simulations show that, in principle, KATRIN will be able to set sterile neutrino mass-dependent limits on the interference strength. The sensitivity is significantly increased if the Q value of the β decay can be sufficiently constrained. However, the sensitivity is not high enough to improve current upper limits from right-handed W boson searches at the LHC.

  12. TMPRSS2-ERG gene fusion in small cell carcinoma of the prostate.

    PubMed

    Guo, Charles C; Dancer, Jane Y; Wang, Yan; Aparicio, Ana; Navone, Nora M; Troncoso, Patricia; Czerniak, Bogdan A

    2011-01-01

    Recent studies have shown that most prostate cancers carry the TMPRSS2-ERG gene fusion. Here we evaluated the TMPRSS2-ERG gene fusion in small cell carcinoma of the prostate (n = 12) in comparison with small cell carcinoma of the urinary bladder (n = 12) and lung (n = 11). Fluorescence in situ hybridization demonstrated rearrangement of the ERG gene in 8 cases of prostatic small cell carcinoma (67%), and the rearrangement was associated with deletion of the 5' ERG gene in 7 cases, but rearrangement of the ERG gene was not present in any small cell carcinoma of the urinary bladder or lung. Next we evaluated the TMPRSS2-ERG gene fusion in nude mouse xenografts that were derived from 2 prostatic small cell carcinomas carrying the TMPRSS2-ERG gene fusion. Two transcripts encoded by the TMPRSS2-ERG gene fusion were detected by reverse transcriptase polymerase chain reaction, and DNA sequencing demonstrated that the 2 transcripts were composed of fusions of exon 1 of the TMPRSS2 gene to exon 4 or 5 of the ERG gene. Our study demonstrates the specific presence of TMPRSS2-ERG gene fusion in prostatic small cell carcinoma, which may be helpful in distinguishing small cell carcinoma of prostatic origin from nonprostatic origins. The high prevalence of the TMPRSS2-ERG gene fusion in prostatic small cell carcinoma as well as adenocarcinoma implies that small cell carcinoma may share a common pathogenic pathway with adenocarcinoma in the prostate. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. hERG K+ channel-associated cardiac effects of the antidepressant drug desipramine.

    PubMed

    Staudacher, Ingo; Wang, Lu; Wan, Xiaoping; Obers, Sabrina; Wenzel, Wolfgang; Tristram, Frank; Koschny, Ronald; Staudacher, Kathrin; Kisselbach, Jana; Koelsch, Patrick; Schweizer, Patrick A; Katus, Hugo A; Ficker, Eckhard; Thomas, Dierk

    2011-02-01

    Cardiac side effects of antidepressant drugs are well recognized. Adverse effects precipitated by the tricyclic drug desipramine include prolonged QT intervals, torsade de pointes tachycardia, heart failure, and sudden cardiac death. QT prolongation has been primarily attributed to acute blockade of hERG/I(Kr) currents. This study was designed to provide a more complete picture of cellular effects associated with desipramine. hERG channels were expressed in Xenopus laevis oocytes and human embryonic kidney (HEK 293) cells, and potassium currents were recorded using patch clamp and two-electrode voltage clamp electrophysiology. Ventricular action potentials were recorded from guinea pig cardiomyocytes. Protein trafficking and cell viability were evaluated in HEK 293 cells and in HL-1 mouse cardiomyocytes by immunocytochemistry, Western blot analysis, or colorimetric MTT assay, respectively. We found that desipramine reduced hERG currents by binding to a receptor site inside the channel pore. hERG protein surface expression was reduced after short-term treatment, revealing a previously unrecognized mechanism. When long-term effects were studied, forward trafficking was impaired and hERG currents were decreased. Action potential duration was prolonged upon acute and chronic desipramine exposure. Finally, desipramine triggered apoptosis in cells expressing hERG channels. Desipramine exerts at least four different cellular effects: (1) direct hERG channel block, (2) acute reduction of hERG surface expression, (3) chronic disruption of hERG trafficking, and (4) induction of apoptosis. These data highlight the complexity of hERG-associated drug effects.

  14. Articular cartilage endurance and resistance to osteoarthritic changes require transcription factor Erg.

    PubMed

    Ohta, Yoichi; Okabe, Takahiro; Larmour, Colleen; Di Rocco, Agnese; Maijenburg, Marijke W; Phillips, Amanda; Speck, Nancy A; Wakitani, Shigeyuki; Nakamura, Takashi; Yamada, Yoshihiko; Enomoto-Iwamoto, Motomi; Pacifici, Maurizio; Iwamoto, Masahiro

    2015-10-01

    To determine whether and how the transcription factor Erg participates in the genesis, establishment, and maintenance of articular cartilage. Floxed Erg mice were mated with Gdf5-Cre mice to generate conditional mutants lacking Erg in their joints. Joints of mutant and control mice were subjected to morphologic and molecular characterization and also to experimental surgically induced osteoarthritis (OA). Gene expression, promoter reporter assays, and gain- and loss-of-function in vitro tests were used to characterize molecular mechanisms of Erg action. Conditional Erg ablation did not elicit obvious changes in limb joint development and overall phenotype in juvenile mice. However, as mice aged, joints of mutant mice degenerated spontaneously and exhibited clear OA-like phenotypic defects. Joints in juvenile mutant mice were more sensitive to surgically induced OA and became defective sooner than operated joints in control mice. Global gene expression data and other studies identified parathyroid hormone-related protein (PTHrP) and lubricin as possible downstream effectors and mediators of Erg action in articular chondrocytes. Reporter assays using control and mutated promoter-enhancer constructs indicated that Erg acted on Ets DNA binding sites to stimulate PTHrP expression. Erg was up-regulated in severely affected areas in human OA articular cartilage but remained barely appreciable in areas of less affected cartilage. The study shows for the first time that Erg is a critical molecular regulator of the endurance of articular cartilage during postnatal life and that Erg can mitigate spontaneous and experimental OA. Erg appears to do this through regulating expression of PTHrP and lubricin, factors known for their protective roles in joints. © 2015, American College of Rheumatology.

  15. Tuning hERG out: Antitarget QSAR Models for Drug Development

    PubMed Central

    Braga, Rodolpho C.; Alves, Vinícius M.; Silva, Meryck F. B.; Muratov, Eugene; Fourches, Denis; Tropsha, Alexander; Andrade, Carolina H.

    2015-01-01

    Several non-cardiovascular drugs have been withdrawn from the market due to their inhibition of hERG K+ channels that can potentially lead to severe heart arrhythmia and death. As hERG safety testing is a mandatory FDA-required procedure, there is a considerable interest for developing predictive computational tools to identify and filter out potential hERG blockers early in the drug discovery process. In this study, we aimed to generate predictive and well-characterized quantitative structure–activity relationship (QSAR) models for hERG blockage using the largest publicly available dataset of 11,958 compounds from the ChEMBL database. The models have been developed and validated according to OECD guidelines using four types of descriptors and four different machine-learning techniques. The classification accuracies discriminating blockers from non-blockers were as high as 0.83–0.93 on external set. Model interpretation revealed several SAR rules, which can guide structural optimization of some hERG blockers into non-blockers. We have also applied the generated models for screening the World Drug Index (WDI) database and identify putative hERG blockers and non-blockers among currently marketed drugs. The developed models can reliably identify blockers and non-blockers, which could be useful for the scientific community. A freely accessible web server has been developed allowing users to identify putative hERG blockers and non-blockers in chemical libraries of their interest (http://labmol.farmacia.ufg.br/predherg). PMID:24805060

  16. Getting to the heart of hERG K+ channel gating

    PubMed Central

    Perry, Matthew D; Ng, Chai-Ann; Mann, Stefan A; Sadrieh, Arash; Imtiaz, Mohammad; Hill, Adam P; Vandenberg, Jamie I

    2015-01-01

    Potassium ion channels encoded by the human ether-a-go-go related gene (hERG) form the ion-conducting subunit of the rapid delayed rectifier potassium current (IKr). Although hERG channels exhibit a widespread tissue distribution they play a particularly important role in the heart. There has been considerable interest in hERG K+ channels for three main reasons. First, they have very unusual gating kinetics, most notably rapid and voltage-dependent inactivation coupled to slow deactivation, which has led to the suggestion that they may play a specific role in the suppression of arrhythmias. Second, mutations in hERG are the cause of 30–40% of cases of congenital long QT syndrome (LQTS), the commonest inherited primary arrhythmia syndrome. Third, hERG is the molecular target for the vast majority of drugs that cause drug-induced LQTS, the commonest cause of drug-induced arrhythmias and cardiac death. Drug-induced LQTS has now been reported for a large range of both cardiac and non-cardiac drugs, in which this side effect is entirely undesired. In recent years there have been comprehensive reviews published on hERG K+ channels (Vandenberg et al. 2012) and we will not re-cover this ground. Rather, we focus on more recent work on the structural basis and dynamics of hERG gating with an emphasis on how the latest developments may facilitate translational research in the area of stratifying risk of arrhythmias. PMID:25820318

  17. Voltage-Dependent Gating of hERG Potassium Channels

    PubMed Central

    Cheng, Yen May; Claydon, Tom W.

    2012-01-01

    The mechanisms by which voltage-gated channels sense changes in membrane voltage and energetically couple this with opening of the ion conducting pore has been the source of significant interest. In voltage-gated potassium (Kv) channels, much of our knowledge in this area comes from Shaker-type channels, for which voltage-dependent gating is quite rapid. In these channels, activation and deactivation are associated with rapid reconfiguration of the voltage-sensing domain unit that is electromechanically coupled, via the S4–S5 linker helix, to the rate-limiting opening of an intracellular pore gate. However, fast voltage-dependent gating kinetics are not typical of all Kv channels, such as Kv11.1 (human ether-à-go-go related gene, hERG), which activates and deactivates very slowly. Compared to Shaker channels, our understanding of the mechanisms underlying slow hERG gating is much poorer. Here, we present a comparative review of the structure–function relationships underlying activation and deactivation gating in Shaker and hERG channels, with a focus on the roles of the voltage-sensing domain and the S4–S5 linker that couples voltage sensor movements to the pore. Measurements of gating current kinetics and fluorimetric analysis of voltage sensor movement are consistent with models suggesting that the hERG activation pathway contains a voltage independent step, which limits voltage sensor transitions. Constraints upon hERG voltage sensor movement may result from loose packing of the S4 helices and additional intra-voltage sensor counter-charge interactions. More recent data suggest that key amino acid differences in the hERG voltage-sensing unit and S4–S5 linker, relative to fast activating Shaker-type Kv channels, may also contribute to the increased stability of the resting state of the voltage sensor. PMID:22586397

  18. Targeting TMPRSS2-ERG in Prostate Cancer

    DTIC Science & Technology

    2015-09-01

    small molecule microarrays ( SMM ) with lysates overexpressing ERG (months 1-12) 3a. Request compounds from compound management that scored from...preliminary SMM screen using 293T lysates overexpressing ERG (months 1-2 – completed November 2013) 3b. Reprint slides with compounds from 3a for...counter SMM assays (months 3-4 – completed December 2013) 3c. Perform counter SMM assay with 293T lysates expressing unrelated protein (months 5-10

  19. Targeting TMPRSS2-ERG in Prostate Cancer

    DTIC Science & Technology

    2014-09-01

    microarrays ( SMM ) with lysates overexpressing ERG (months 1-12) 3a. Request compounds from compound management that scored from preliminary SMM ...screen using 293T lysates overexpressing ERG (months 1-2 – completed November 2013) 3b. Reprint slides with compounds from 3a for counter SMM ...assays (months 3-4 – completed December 2013) 3c. Perform counter SMM assay with 293T lysates expressing unrelated protein (months 5-10 – completed

  20. Immunohistochemical expression of ERG in the molecular epidemiology of fatal prostate cancer study.

    PubMed

    Weinmann, Sheila; Van Den Eeden, Stephen K; Haque, Reina; Chen, Chuhe; Richert-Boe, Kathryn; Schwartzman, Jacob; Gao, Lina; Berry, Deborah L; Kallakury, Bhaskar V S; Alumkal, Joshi J

    2013-09-01

    Gene fusions between the ERG transcription factor and the androgen-regulated gene TMPRSS2 occur in a subset of prostate cancers and contribute to transformation of prostatic epithelial cells. Prior reports have used fluorescence in situ hybridization (FISH) or quantitative PCR (QPCR) to determine the presence of TMPRSS2-ERG fusions or ERG expression, respectively. Recently, several groups have reported on immunohistochemistry (IHC) to measure ERG expression, which is much more readily performed in clinical practice. However, the prior studies examining ERG expression by IHC had small sample sizes or they failed to clarify the association of ERG protein expression with important clinico-pathological features or prostate cancer-specific mortality. To address these deficits, we evaluated ERG expression by IHC in 208 radical prostatectomy samples from the Kaiser Permanente Molecular Epidemiology of Fatal Prostate Cancer (MEFPC) study, a case-control study of prostate cancer-specific mortality. Nuclear ERG expression was seen in neoplastic prostate epithelia in 49 of the samples (23.7%). ERG expression in tumor cells was associated with higher tumor stage (OR = 2.0, 95% confidence interval 1.0-4.0, P value = 0.04). ERG immunoreactivity was positively associated with prostate cancer-specific mortality, although the confidence interval was wide (OR = 1.9, 95% confidence interval 0.88-4.0, P value = 0.10). Our results demonstrate that ERG protein expression is readily quantifiable with an existing commercial antibody. Evaluating ERG protein expression may improve our ability to identify the subset of more aggressive, invasive prostate cancers. © 2013 Wiley Periodicals, Inc.

  1. Antibody-independent Targeted Quantification of TMPRSS2-ERG Fusion Protein Products in Prostate Cancer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    He, Jintang; Sun, Xuefei; Shi, Tujin

    2014-10-01

    Fusions between the transmembrane protease serine 2 (TMPRSS2) and ETS related gene (ERG) represent one of the most specific biomarkers that define a distinct molecular subtype of prostate cancer. The studies on TMPRSS2-ERG gene fusions have seldom been performed at the protein level, primarily due to the lack of high-quality antibodies or an antibody-independent method that is sufficiently sensitive for detecting the truncated ERG protein products resulting from TMPRSS2-ERG gene fusions and alternative splicing. Herein, we applied a recently developed PRISM (high-pressure high-resolution separations with intelligent selection and multiplexing)-SRM (selected reaction monitoring) strategy for quantifying ERG protein in prostate cancermore » cell lines and tumors. The highly sensitive PRISM-SRM assays led to confident detection of 6 unique ERG peptides in either the TMPRSS2-ERG positive cell lines or tissues but not in the negative controls, indicating that ERG protein expression is highly correlated with TMPRSS2-ERG gene rearrangements. Significantly, our results demonstrated for the first time that at least two groups of ERG protein isoforms were simultaneously expressed at variable levels in TMPRSS2-ERG positive samples as evidenced by concomitant detection of two mutually exclusive peptides. Three peptides shared across almost all fusion protein products were determined to be the most abundant peptides, and hence can be used as “signature” peptides for detecting ERG overexpression resulting from TMPRSS2-ERG gene fusion. These PRISM-SRM assays provide valuable tools for studying TMPRSS2-ERG gene fusion protein products, thus improving our understanding of the role of TMPRSS2-ERG gene fusion in the biology of prostate cancer.« less

  2. Hsp40 Chaperones Promote Degradation of the hERG Potassium Channel*

    PubMed Central

    Walker, Valerie E.; Wong, Michael J. H.; Atanasiu, Roxana; Hantouche, Christine; Young, Jason C.; Shrier, Alvin

    2010-01-01

    Loss of function mutations in the hERG (human ether-a-go-go related gene or KCNH2) potassium channel underlie the proarrhythmic cardiac long QT syndrome type 2. Most often this is a consequence of defective trafficking of hERG mutants to the cell surface, with channel retention and degradation at the endoplasmic reticulum. Here, we identify the Hsp40 type 1 chaperones DJA1 (DNAJA1/Hdj2) and DJA2 (DNAJA2) as key modulators of hERG degradation. Overexpression of the DJAs reduces hERG trafficking efficiency, an effect eliminated by the proteasomal inhibitor lactacystin or with DJA mutants lacking their J domains essential for Hsc70/Hsp70 activation. Both DJA1 and DJA2 cause a decrease in the amount of hERG complexed with Hsc70, indicating a preferential degradation of the complex. Similar effects were observed with the E3 ubiquitin ligase CHIP. Both the DJAs and CHIP reduce hERG stability and act differentially on folding intermediates of hERG and the disease-related trafficking mutant G601S. We propose a novel role for the DJA proteins in regulating degradation and suggest that they act at a critical point in secretory pathway quality control. PMID:19940115

  3. ERG Expression Levels in Prostate Tumors Reflect Functional Status of the Androgen Receptor (AR) as a Consequence of Fusion of ERG with AR Regulated Gene Promoters

    DTIC Science & Technology

    2010-01-01

    mathematically defined in the following formulas. ARGI = Σ (I PMEPA1 + IPSA +INKX3.1+IODC1+IAMD1) ARFI=CI=ARGI+IERG Detection of TMPRSS2-ERG Fusion Junctions...ERG expression into the Androgen Receptor Function Index, ARFI. ARGI = Σ (I PMEPA1 + IPSA +INKX3.1+IODC1+IAMD1) ARFI=CI=ARGI+IERG In the high ERG

  4. Getting to the heart of hERG K(+) channel gating.

    PubMed

    Perry, Matthew D; Ng, Chai-Ann; Mann, Stefan A; Sadrieh, Arash; Imtiaz, Mohammad; Hill, Adam P; Vandenberg, Jamie I

    2015-06-15

    Potassium ion channels encoded by the human ether-a-go-go related gene (hERG) form the ion-conducting subunit of the rapid delayed rectifier potassium current (IKr ). Although hERG channels exhibit a widespread tissue distribution they play a particularly important role in the heart. There has been considerable interest in hERG K(+) channels for three main reasons. First, they have very unusual gating kinetics, most notably rapid and voltage-dependent inactivation coupled to slow deactivation, which has led to the suggestion that they may play a specific role in the suppression of arrhythmias. Second, mutations in hERG are the cause of 30-40% of cases of congenital long QT syndrome (LQTS), the commonest inherited primary arrhythmia syndrome. Third, hERG is the molecular target for the vast majority of drugs that cause drug-induced LQTS, the commonest cause of drug-induced arrhythmias and cardiac death. Drug-induced LQTS has now been reported for a large range of both cardiac and non-cardiac drugs, in which this side effect is entirely undesired. In recent years there have been comprehensive reviews published on hERG K(+) channels (Vandenberg et al. 2012) and we will not re-cover this ground. Rather, we focus on more recent work on the structural basis and dynamics of hERG gating with an emphasis on how the latest developments may facilitate translational research in the area of stratifying risk of arrhythmias. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  5. Global Analysis Reveals Families of Chemical Motifs Enriched for hERG Inhibitors

    PubMed Central

    Du, Fang; Babcock, Joseph J.; Yu, Haibo; Zou, Beiyan; Li, Min

    2015-01-01

    Promiscuous inhibition of the human ether-à-go-go-related gene (hERG) potassium channel by drugs poses a major risk for life threatening arrhythmia and costly drug withdrawals. Current knowledge of this phenomenon is derived from a limited number of known drugs and tool compounds. However, in a diverse, naïve chemical library, it remains unclear which and to what degree chemical motifs or scaffolds might be enriched for hERG inhibition. Here we report electrophysiology measurements of hERG inhibition and computational analyses of >300,000 diverse small molecules. We identify chemical ‘communities’ with high hERG liability, containing both canonical scaffolds and structurally distinctive molecules. These data enable the development of more effective classifiers to computationally assess hERG risk. The resultant predictive models now accurately classify naïve compound libraries for tendency of hERG inhibition. Together these results provide a more complete reference map of characteristic chemical motifs for hERG liability and advance a systematic approach to rank chemical collections for cardiotoxicity risk. PMID:25700001

  6. Molecular dynamics studies on the DNA-binding process of ERG.

    PubMed

    Beuerle, Matthias G; Dufton, Neil P; Randi, Anna M; Gould, Ian R

    2016-11-15

    The ETS family of transcription factors regulate gene targets by binding to a core GGAA DNA-sequence. The ETS factor ERG is required for homeostasis and lineage-specific functions in endothelial cells, some subset of haemopoietic cells and chondrocytes; its ectopic expression is linked to oncogenesis in multiple tissues. To date details of the DNA-binding process of ERG including DNA-sequence recognition outside the core GGAA-sequence are largely unknown. We combined available structural and experimental data to perform molecular dynamics simulations to study the DNA-binding process of ERG. In particular we were able to reproduce the ERG DNA-complex with a DNA-binding simulation starting in an unbound configuration with a final root-mean-square-deviation (RMSD) of 2.1 Å to the core ETS domain DNA-complex crystal structure. This allowed us to elucidate the relevance of amino acids involved in the formation of the ERG DNA-complex and to identify Arg385 as a novel key residue in the DNA-binding process. Moreover we were able to show that water-mediated hydrogen bonds are present between ERG and DNA in our simulations and that those interactions have the potential to achieve sequence recognition outside the GGAA core DNA-sequence. The methodology employed in this study shows the promising capabilities of modern molecular dynamics simulations in the field of protein DNA-interactions.

  7. Reduction in cryptosporidiosis associated with introduction of enhanced filtration of drinking water at Loch Katrine, Scotland.

    PubMed

    Pollock, K G J; Young, D; Robertson, C; Ahmed, S; Ramsay, C N

    2014-01-01

    Previous evidence has suggested an association between cryptosporidiosis and consumption of unfiltered drinking water from Loch Katrine in Scotland. Before September 2007, the water was only micro-strained and chlorinated; however, since that time, coagulation and rapid gravity filtration have been installed. In order to determine risk factors associated with cryptosporidiosis, including drinking water, we analysed data on microbiologically confirmed cases of cryptosporidiosis from 2004 to 2010. We identified an association between the incidence of cryptosporidiosis and unfiltered Loch Katrine drinking water supplied to the home (odds ratio 1.86, 95% confidence interval 1.11-3.11, P = 0.019). However, while filtration appears to be associated with initially reduced rates of cryptosporidiosis, evidence suggests it may paradoxically make those consumers more susceptible to other transmission routes in the long-term. These findings support implementation of similar treatment for other unfiltered drinking-water supplies, as a means of reducing cryptosporidiosis associated with drinking water.

  8. Identification of quaternary ammonium compounds as potent inhibitors of hERG potassium channels

    PubMed Central

    Xia, Menghang; Shahane, Sampada; Huang, Ruili; Titus, Steven A.; Shum, Enoch; Zhao, Yong; Southall, Noel; Zheng, Wei; Witt, Kristine L.; Tice, Raymond R.; Austin, Christopher P.

    2011-01-01

    The human ether-a-go-go-related gene (hERG) channel, a member of a family of voltage-gated potassium (K+) channels, plays a critical role in the repolarization of the cardiac action potential. The reduction of hERG channel activity as a result of adverse drug effects or genetic mutations may cause QT interval prolongation and potentially lead to acquired long QT syndrome. Thus, screening for hERG channel activity is important in drug development. Cardiotoxicity associated with the inhibition of hERG channels by environmental chemicals is also a public health concern. To assess the inhibitory effects of environmental chemicals on hERG channel function, we screened the National Toxicology Program (NTP) collection of 1408 compounds by measuring thallium influx into cells through hERG channels. Seventeen compounds with hERG channel inhibition were identified with IC50 potencies ranging from 0.26 to 22 μM. Twelve of these compounds were confirmed as hERG channel blockers in an automated whole cell patch clamp experiment. In addition, we investigated the structure-activity relationship of seven compounds belonging to the quaternary ammonium compound (QAC) series on hERG channel inhibition. Among four active QAC compounds, tetra-n-octylammonium bromide was the most potent with an IC50 value of 260 nM in the thallium influx assay and 80 nM in the patch clamp assay. The potency of this class of hERG channel inhibitors appears to depend on the number and length of their aliphatic side-chains surrounding the charged nitrogen. Profiling environmental compound libraries for hERG channel inhibition provides information useful in prioritizing these compounds for cardiotoxicity assessment in vivo. PMID:21362439

  9. [Follow-up on MEWDS by fundus perimetry and multifocal ERG with the SLO].

    PubMed

    Bültmann, S; Martin, M; Rohrschneider, K

    2002-09-01

    Most conventional techniques for examination such as perimetry or ERG may not be sensitive enough to detect functional alterations due to MEWDS precisely. We report on a follow-up performed by fundus perimetry and the new technique of multifocal ERG using the scanning laser ophthalmoscope. A 24-year-old female patient (VA 0.2/0.8) was followed up for 7 weeks with these techniques as well as Octopus perimetry, fluorescence angiography, Ganzfeld ERG and biomicroscopy. Multifocal ERG stimulation (mfERG, Retiscan) was performed with the SLO. Visual acuity improved from 0.2 to 0.8 and the central relative scotoma disappeared while a relevant increase of P1-wave amplitudes in mfERG could be observed. Combining objective measurements from the fundus controlled SLO-mfERG and results from fundus perimetry enable good correlation of morphology and results, even for minor alterations of the macula only accessible by few established clinical examinations.

  10. Characterizing the molecular features of ERG-positive tumors in primary and castration resistant prostate cancer.

    PubMed

    Roudier, Martine P; Winters, Brian R; Coleman, Ilsa; Lam, Hung-Ming; Zhang, Xiaotun; Coleman, Roger; Chéry, Lisly; True, Lawrence D; Higano, Celestia S; Montgomery, Bruce; Lange, Paul H; Snyder, Linda A; Srivastava, Shiv; Corey, Eva; Vessella, Robert L; Nelson, Peter S; Üren, Aykut; Morrissey, Colm

    2016-06-01

    The TMPRSS2-ERG gene fusion is detected in approximately half of primary prostate cancers (PCa) yet the prognostic significance remains unclear. We hypothesized that ERG promotes the expression of common genes in primary PCa and metastatic castration-resistant PCa (CRPC), with the objective of identifying ERG-associated pathways, which may promote the transition from primary PCa to CRPC. We constructed tissue microarrays (TMA) from 127 radical prostatectomy specimens, 20 LuCaP patient-derived xenografts (PDX), and 152 CRPC metastases obtained immediately at time of death. Nuclear ERG was assessed by immunohistochemistry (IHC). To characterize the molecular features of ERG-expressing PCa, a subset of IHC confirmed ERG+ or ERG- specimens including 11 radical prostatectomies, 20 LuCaP PDXs, and 45 CRPC metastases underwent gene expression analysis. Genes were ranked based on expression in primary PCa and CRPC. Common genes of interest were targeted for IHC analysis and expression compared with biochemical recurrence (BCR) status. IHC revealed that 43% of primary PCa, 35% of the LuCaP PDXs, and 18% of the CRPC metastases were ERG+ (12 of 48 patients [25%] had at least one ERG+ metastasis). Based on gene expression data and previous literature, two proteins involved in calcium signaling (NCALD, CACNA1D), a protein involved in inflammation (HLA-DMB), CD3 positive immune cells, and a novel ERG-associated protein, DCLK1 were evaluated in primary PCa and CRPC metastases. In ERG+ primary PCa, a weak association was seen with NCALD and CACNA1D protein expression. HLA-DMB association with ERG was decreased and CD3 cell number association with ERG was changed from positive to negative in CRPC metastases compared to primary PCa. DCLK1 was upregulated at the protein level in unpaired ERG+ primary PCa and CRPC metastases (P = 0.0013 and P < 0.0001, respectively). In primary PCa, ERG status or expression of targeted proteins was not associated with BCR-free survival

  11. The Shift of ERG B-Wave Induced by Hours' Dark Exposure in Rodents

    PubMed Central

    Li, Dake; Fang, Qi; Yu, Hongbo

    2016-01-01

    Purpose Dark adaptation can induce a rapid functional shift in the retina, and after that, the retinal function is believed to remain stable during the continuous dark exposure. However, we found that electroretinograms (ERG) b-waves gradually shifted during 24 hours’ dark exposure in rodents. Detailed experiments were designed to explore this non-classical dark adaptation. Methods In vivo ERG recording in adult and developing rodents after light manipulations. Results We revealed a five-fold decrease in ERG b-waves in adult rats that were dark exposed for 24 hours. The ERG b-waves significantly increased within the first hour’s dark exposure, but after that decreased continuously and finally attained steady state after 1 day’s dark exposure. After 3 repetitive, 10 minutes’ light exposure, the dark exposed rats fully recovered. This recovery effect was eye-specific, and light exposure to one eye could not restore the ERGs in the non-exposed eye. The prolonged dark exposure-induced functional shift was also reflected in the down-regulation on the amplitude of intensity-ERG response curve, but the dynamic range of the responsive light intensity remained largely stable. Furthermore, the ERG b-wave shifts occurred in and beyond classical critical period, and in both rats and mice. Importantly, when ERG b-wave greatly shifted, the amplitude of ERG a-wave did not change significantly after the prolonged dark exposure. Conclusions This rapid age-independent ERG change demonstrates a generally existing functional shift in the retina, which is at the entry level of visual system. PMID:27517462

  12. The Shift of ERG B-Wave Induced by Hours' Dark Exposure in Rodents.

    PubMed

    Li, Dake; Fang, Qi; Yu, Hongbo

    2016-01-01

    Dark adaptation can induce a rapid functional shift in the retina, and after that, the retinal function is believed to remain stable during the continuous dark exposure. However, we found that electroretinograms (ERG) b-waves gradually shifted during 24 hours' dark exposure in rodents. Detailed experiments were designed to explore this non-classical dark adaptation. In vivo ERG recording in adult and developing rodents after light manipulations. We revealed a five-fold decrease in ERG b-waves in adult rats that were dark exposed for 24 hours. The ERG b-waves significantly increased within the first hour's dark exposure, but after that decreased continuously and finally attained steady state after 1 day's dark exposure. After 3 repetitive, 10 minutes' light exposure, the dark exposed rats fully recovered. This recovery effect was eye-specific, and light exposure to one eye could not restore the ERGs in the non-exposed eye. The prolonged dark exposure-induced functional shift was also reflected in the down-regulation on the amplitude of intensity-ERG response curve, but the dynamic range of the responsive light intensity remained largely stable. Furthermore, the ERG b-wave shifts occurred in and beyond classical critical period, and in both rats and mice. Importantly, when ERG b-wave greatly shifted, the amplitude of ERG a-wave did not change significantly after the prolonged dark exposure. This rapid age-independent ERG change demonstrates a generally existing functional shift in the retina, which is at the entry level of visual system.

  13. Identification and Characterization of Four Azole-Resistant erg3 Mutants of Candida albicans▿

    PubMed Central

    Martel, Claire M.; Parker, Josie E.; Bader, Oliver; Weig, Michael; Gross, Uwe; Warrilow, Andrew G. S.; Rolley, Nicola; Kelly, Diane E.; Kelly, Steven L.

    2010-01-01

    Sterol analysis identified four Candida albicans erg3 mutants in which ergosta 7,22-dienol, indicative of perturbations in sterol Δ5,6-desaturase (Erg3p) activity, comprised >5% of the total sterol fraction. The erg3 mutants (CA12, CA488, CA490, and CA1008) were all resistant to fluconazole, voriconazole, itraconazole, ketoconazole, and clotrimazole under standard CLSI assay conditions (MIC values, ≥256, 16, 16, 8, and 1 μg ml−1, respectively). Importantly, CA12 and CA1008 retained an azole-resistant phenotype even when assayed in the presence of FK506, a multidrug efflux inhibitor. Conversely, CA488, CA490, and three comparator isolates (CA6, CA14, and CA177, in which ergosterol comprised >80% of the total sterol fraction and ergosta 7,22-dienol was undetectable) all displayed azole-sensitive phenotypes under efflux-inhibited assay conditions. Owing to their ergosterol content, CA6, CA14, and CA177 were highly sensitive to amphotericin B (MIC values, <0.25 μg ml−1); CA1008, in which ergosterol comprised <2% of the total sterol fraction, was less sensitive (MIC, 1 μg ml−1). CA1008 harbored multiple amino acid substitutions in Erg3p but only a single conserved polymorphism (E266D) in sterol 14α-demethylase (Erg11p). CA12 harbored one substitution (W332R) in Erg3p and no residue changes in Erg11p. CA488 and CA490 were found to harbor multiple residue changes in both Erg3p and Erg11p. The results suggest that missense mutations in ERG3 might arise in C. albicans more frequently than currently supposed and that the clinical significance of erg3 mutants, including those in which additional mechanisms also contribute to resistance, should not be discounted. PMID:20733039

  14. Development of Peptidomimetic Inhibitors of the ERG Gene Fusion Product in Prostate Cancer.

    PubMed

    Wang, Xiaoju; Qiao, Yuanyuan; Asangani, Irfan A; Ateeq, Bushra; Poliakov, Anton; Cieślik, Marcin; Pitchiaya, Sethuramasundaram; Chakravarthi, Balabhadrapatruni V S K; Cao, Xuhong; Jing, Xiaojun; Wang, Cynthia X; Apel, Ingrid J; Wang, Rui; Tien, Jean Ching-Yi; Juckette, Kristin M; Yan, Wei; Jiang, Hui; Wang, Shaomeng; Varambally, Sooryanarayana; Chinnaiyan, Arul M

    2017-04-10

    Transcription factors play a key role in the development of diverse cancers, and therapeutically targeting them has remained a challenge. In prostate cancer, the gene encoding the transcription factor ERG is recurrently rearranged and plays a critical role in prostate oncogenesis. Here, we identified a series of peptides that interact specifically with the DNA binding domain of ERG. ERG inhibitory peptides (EIPs) and derived peptidomimetics bound ERG with high affinity and specificity, leading to proteolytic degradation of the ERG protein. The EIPs attenuated ERG-mediated transcription, chromatin recruitment, protein-protein interactions, cell invasion and proliferation, and tumor growth. Thus, peptidomimetic targeting of transcription factor fusion products may provide a promising therapeutic strategy for prostate cancer as well as other malignancies. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. ERG and other discriminators between advanced hydroxychloroquine retinopathy and retinitis pigmentosa.

    PubMed

    Nair, Archana A; Marmor, Michael F

    2017-06-01

    To study whether the ERG and other clinical findings help to distinguish between advanced hydroxychloroquine (HCQ) retinopathy and pericentral or diffuse retinitis pigmentosa (RP) with similar fundus appearance. We conducted a retrospective analysis of patients with advanced HCQ retinopathy (n = 11), pericentral RP (n = 8) and diffuse RP (n = 8). Pericentral RP was defined as having limited fundus damage and relatively normal flicker ERG time-to-peak. Diffuse RP had typical loss of the rod ERG and flicker timing delay. All patients showed reduced amplitude of the ISCEV responses in the full-field electroretinogram (ERG). Aspects of history, visual field results, fundus appearance, fundus autofluorescence and ocular coherence tomography were also compared. Relative to pericentral RP, patients with HCQ toxicity showed delayed flicker ERG time-to-peak and lower ERG amplitudes, particularly combined rod-cone responses. Relative to diffuse RP, most HCQ toxicity patients had some preserved rod ERG response, and there was no obvious predilection for rod over cone damage. In addition, patients with HCQ toxicity usually lacked markers of long-standing degeneration such as bone spicule figures or severe loss of peripheral field. History of familial disease and long-standing night blindness were specific to RP. While the early signs of HCQ damage are typically regional in the posterior pole, advanced disease is characteristically diffuse (unlike pericentral RP). This is appropriate for a systemic toxin, as is the finding that rods and cones were both affected in the ERG to a similar degree (unlike genetic rod-cone dystrophies). For patients with severe HCQ exposure and some of our discriminatory findings, and no family history or prior night blindness, HCQ toxicity is a sufficient diagnosis without invoking a second rare disease (Occam's razor).

  16. Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mertens, Susanne

    In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

  17. Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

    DOE PAGES

    Mertens, Susanne

    2015-03-24

    In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

  18. Channel sialic acids limit hERG channel activity during the ventricular action potential.

    PubMed

    Norring, Sarah A; Ednie, Andrew R; Schwetz, Tara A; Du, Dongping; Yang, Hui; Bennett, Eric S

    2013-02-01

    Activity of human ether-a-go-go-related gene (hERG) 1 voltage-gated K(+) channels is responsible for portions of phase 2 and phase 3 repolarization of the human ventricular action potential. Here, we questioned whether and how physiologically and pathophysiologically relevant changes in surface N-glycosylation modified hERG channel function. Voltage-dependent hERG channel gating and activity were evaluated as expressed in a set of Chinese hamster ovary (CHO) cell lines under conditions of full glycosylation, no sialylation, no complex N-glycans, and following enzymatic deglycosylation of surface N-glycans. For each condition of reduced glycosylation, hERG channel steady-state activation and inactivation relationships were shifted linearly by significant depolarizing ∼9 and ∼18 mV, respectively. The hERG window current increased significantly by 50-150%, and the peak shifted by a depolarizing ∼10 mV. There was no significant change in maximum hERG current density. Deglycosylated channels were significantly more active (20-80%) than glycosylated controls during phases 2 and 3 of action potential clamp protocols. Simulations of hERG current and ventricular action potentials corroborated experimental data and predicted reduced sialylation leads to a 50-70-ms decrease in action potential duration. The data describe a novel mechanism by which hERG channel gating is modulated through physiologically and pathophysiologically relevant changes in N-glycosylation; reduced channel sialylation increases hERG channel activity during the action potential, thereby increasing the rate of action potential repolarization.

  19. Characterizing the molecular features of ERG-positive tumors in primary and castration resistant prostate cancer

    PubMed Central

    Roudier, Martine P; Winters, Brian R; Coleman, Ilsa; Lam, Hung-Ming; Zhang, Xiaotun; Coleman, Roger; Chéry, Lisly; True, Lawrence D.; Higano, Celestia S.; Montgomery, Bruce; Lange, Paul H.; Snyder, Linda A.; Srivistava, Shiv; Corey, Eva; Vessella, Robert L.; Nelson, Peter S.; Üren, Aykut; Morrissey, Colm

    2017-01-01

    Background The TMPRSS2-ERG gene fusion is detected in approximately half of primary prostate cancers (PCa) yet the prognostic significance remains unclear. We hypothesized that ERG promotes the expression of common genes in primary PCa and metastatic castration-resistant PCa (CRPC), with the objective of identifying ERG-associated pathways, which may promote the transition from primary PCa to CRPC. Methods We constructed tissue microarrays (TMA) from 127 radical prostatectomy specimens, 20 LuCaP patient-derived xenografts (PDX), and 152 CRPC metastases obtained immediately at time of death. Nuclear ERG was assessed by immunohistochemistry (IHC). To characterize the molecular features of ERG-expressing PCa, a subset of IHC confirmed ERG+ or ERG-specimens including 11 radical prostatectomies, 20 LuCaP PDXs, and 45 CRPC metastases underwent gene expression analysis. Genes were ranked based on expression in primary PCa and CRPC. Common genes of interest were targeted for IHC analysis and expression compared with biochemical recurrence (BCR) status. Results IHC revealed that 43% of primary PCa, 35% of the LuCaP PDXs, and 18% of the CRPC metastases were ERG+ (12 of 48 patients [25%] had at least 1 ERG+ metastasis). Based on gene expression data and previous literature, two proteins involved in calcium signaling (NCALD, CACNA1D), a protein involved in inflammation (HLA-DMB), CD3 positive immune cells, and a novel ERG-associated protein, DCLK1 were evaluated in primary PCa and CRPC metastases. In ERG+ primary PCa, a weak association was seen with NCALD and CACNA1D protein expression. HLA-DMB expression and the presence of CD3 positive immune cells were decreased in CRPC metastases compared to primary PCa. DCLK1 was upregulated at the protein level in unpaired ERG+ primary PCa and CRPC metastases (p=0.0013 and p<0.0001, respectively). In primary PCa, ERG status or expression of targeted proteins was not associated with BCR-free survival. However for primary PCa, ERG+DCLK1

  20. Compilation and physicochemical classification analysis of a diverse hERG inhibition database

    NASA Astrophysics Data System (ADS)

    Didziapetris, Remigijus; Lanevskij, Kiril

    2016-12-01

    A large and chemically diverse hERG inhibition data set comprised of 6690 compounds was constructed on the basis of ChEMBL bioactivity database and original publications dealing with experimental determination of hERG activities using patch-clamp and competitive displacement assays. The collected data were converted to binary format at 10 µM activity threshold and subjected to gradient boosting machine classification analysis using a minimal set of physicochemical and topological descriptors. The tested parameters involved lipophilicity (log P), ionization (p K a ), polar surface area, aromaticity, molecular size and flexibility. The employed approach allowed classifying the compounds with an overall 75-80 % accuracy, even though it only accounted for non-specific interactions between hERG and ligand molecules. The observed descriptor-response profiles were consistent with common knowledge about hERG ligand binding site, but also revealed several important quantitative trends, as well as slight inter-assay variability in hERG inhibition data. The results suggest that even weakly basic groups (p K a < 6) might substantially contribute to hERG inhibition potential, whereas the role of lipophilicity depends on the compound's ionization state, and the influence of log P decreases in the order of bases > zwitterions > neutrals > acids. Given its robust performance and clear physicochemical interpretation, the proposed model may provide valuable information to direct drug discovery efforts towards compounds with reduced risk of hERG-related cardiotoxicity.

  1. Dynamic regulation of canonical TGFβ signalling by endothelial transcription factor ERG protects from liver fibrogenesis.

    PubMed

    Dufton, Neil P; Peghaire, Claire R; Osuna-Almagro, Lourdes; Raimondi, Claudio; Kalna, Viktoria; Chuahan, Abhishek; Webb, Gwilym; Yang, Youwen; Birdsey, Graeme M; Lalor, Patricia; Mason, Justin C; Adams, David H; Randi, Anna M

    2017-10-12

    The role of the endothelium in protecting from chronic liver disease and TGFβ-mediated fibrosis remains unclear. Here we describe how the endothelial transcription factor ETS-related gene (ERG) promotes liver homoeostasis by controlling canonical TGFβ-SMAD signalling, driving the SMAD1 pathway while repressing SMAD3 activity. Molecular analysis shows that ERG binds to SMAD3, restricting its access to DNA. Ablation of ERG expression results in endothelial-to-mesenchymal transition (EndMT) and spontaneous liver fibrogenesis in EC-specific constitutive hemi-deficient (Erg cEC-Het ) and inducible homozygous deficient mice (Erg iEC-KO ), in a SMAD3-dependent manner. Acute administration of the TNF-α inhibitor etanercept inhibits carbon tetrachloride (CCL 4 )-induced fibrogenesis in an ERG-dependent manner in mice. Decreased ERG expression also correlates with EndMT in tissues from patients with end-stage liver fibrosis. These studies identify a pathogenic mechanism where loss of ERG causes endothelial-dependent liver fibrogenesis via regulation of SMAD2/3. Moreover, ERG represents a promising candidate biomarker for assessing EndMT in liver disease.The transcription factor ERG is key to endothelial lineage specification and vascular homeostasis. Here the authors show that ERG balances TGFβ signalling through the SMAD1 and SMAD3 pathways, protecting the endothelium from endothelial-to-mesenchymal transition and consequent liver fibrosis in mice via a SMAD3-dependent mechanism.

  2. Physical and functional interaction between integrins and hERG potassium channels.

    PubMed

    Arcangeli, A; Becchetti, A; Cherubini, A; Crociani, O; Defilippi, P; Guasti, L; Hofmann, G; Pillozzi, S; Olivotto, M; Wanke, E

    2004-11-01

    Integrins are adhesion receptors capable of transmitting intracellular signals that regulate many different cellular functions. Among integrin-mediated signals, the activation of ion channels can be included. We demonstrated that a long-lasting activation of hERG (human ether-a-go-go-related gene) potassium channels occurs in both human neuroblastoma and leukaemia cells after the activation of the beta1 integrin subunit. This activation is apparently a determining factor inducing neurite extension and osteoclastic differentiation in both the cell types. More recently, we provided evidences that beta1 integrins and hERG channels co-precipitate in both the cell types. Preliminary results suggest that a macromolecular signalling complex indeed occurs between integrins and the hERG1 protein and that hERG channel activity can modulate integrin downstream signalling.

  3. Characterization of Erg K+ Channels in α- and β-Cells of Mouse and Human Islets*

    PubMed Central

    Hardy, Alexandre B.; Fox, Jocelyn E. Manning; Giglou, Pejman Raeisi; Wijesekara, Nadeeja; Bhattacharjee, Alpana; Sultan, Sobia; Gyulkhandanyan, Armen V.; Gaisano, Herbert Y.; MacDonald, Patrick E.; Wheeler, Michael B.

    2009-01-01

    Voltage-gated eag-related gene (Erg) K+ channels regulate the electrical activity of many cell types. Data regarding Erg channel expression and function in electrically excitable glucagon and insulin producing cells of the pancreas is limited. In the present study Erg1 mRNA and protein were shown to be highly expressed in human and mouse islets and in α-TC6 and Min6 cells α- and β-cell lines, respectively. Whole cell patch clamp recordings demonstrated the functional expression of Erg1 in α- and β-cells, with rBeKm1, an Erg1 antagonist, blocking inward tail currents elicited by a double pulse protocol. Additionally, a small interference RNA approach targeting the kcnh2 gene (Erg1) induced a significant decrease of Erg1 inward tail current in Min6 cells. To investigate further the role of Erg channels in mouse and human islets, ratiometric Fura-2 AM Ca2+-imaging experiments were performed on isolated α- and β-cells. Blocking Erg channels with rBeKm1 induced a transient cytoplasmic Ca2+ increase in both α- and β-cells. This resulted in an increased glucose-dependent insulin secretion, but conversely impaired glucagon secretion under low glucose conditions. Together, these data present Erg1 channels as new mediators of α- and β-cell repolarization. However, antagonism of Erg1 has divergent effects in these cells; to augment glucose-dependent insulin secretion and inhibit low glucose stimulated glucagon secretion. PMID:19690348

  4. Ion Conduction through the hERG Potassium Channel

    PubMed Central

    Cavalli, Andrea; Recanatini, Maurizio

    2012-01-01

    The inward rectifier voltage-gated potassium channel hERG is of primary importance for the regulation of the membrane potential of cardiomyocytes. Unlike most voltage-gated K+-channels, hERG shows a low elementary conductance at physiological voltage and potassium concentration. To investigate the molecular features underlying this unusual behavior, we simulated the ion conduction through the selectivity filter at a fully atomistic level by means of molecular dynamics-based methods, using a homology-derived model. According to our calculations, permeation of potassium ions can occur along two pathways, one involving site vacancies inside the filter (showing an energy barrier of about 6 kcal mol−1), and the other characterized by the presence of a knock-on intermediate (about 8 kcal mol−1). These barriers are indeed in accordance with a low conductance behavior, and can be explained in terms of a series of distinctive structural features displayed by the hERG ion permeation pathway. PMID:23133669

  5. Theory, modeling, and integrated studies in the Arase (ERG) project

    NASA Astrophysics Data System (ADS)

    Seki, Kanako; Miyoshi, Yoshizumi; Ebihara, Yusuke; Katoh, Yuto; Amano, Takanobu; Saito, Shinji; Shoji, Masafumi; Nakamizo, Aoi; Keika, Kunihiro; Hori, Tomoaki; Nakano, Shin'ya; Watanabe, Shigeto; Kamiya, Kei; Takahashi, Naoko; Omura, Yoshiharu; Nose, Masahito; Fok, Mei-Ching; Tanaka, Takashi; Ieda, Akimasa; Yoshikawa, Akimasa

    2018-02-01

    Understanding of underlying mechanisms of drastic variations of the near-Earth space (geospace) is one of the current focuses of the magnetospheric physics. The science target of the geospace research project Exploration of energization and Radiation in Geospace (ERG) is to understand the geospace variations with a focus on the relativistic electron acceleration and loss processes. In order to achieve the goal, the ERG project consists of the three parts: the Arase (ERG) satellite, ground-based observations, and theory/modeling/integrated studies. The role of theory/modeling/integrated studies part is to promote relevant theoretical and simulation studies as well as integrated data analysis to combine different kinds of observations and modeling. Here we provide technical reports on simulation and empirical models related to the ERG project together with their roles in the integrated studies of dynamic geospace variations. The simulation and empirical models covered include the radial diffusion model of the radiation belt electrons, GEMSIS-RB and RBW models, CIMI model with global MHD simulation REPPU, GEMSIS-RC model, plasmasphere thermosphere model, self-consistent wave-particle interaction simulations (electron hybrid code and ion hybrid code), the ionospheric electric potential (GEMSIS-POT) model, and SuperDARN electric field models with data assimilation. ERG (Arase) science center tools to support integrated studies with various kinds of data are also briefly introduced.[Figure not available: see fulltext.

  6. The relationship of TMPRSS2-ERG gene fusion between primary and metastatic prostate cancers.

    PubMed

    Guo, Charles C; Wang, Yan; Xiao, Li; Troncoso, Patricia; Czerniak, Bogdan A

    2012-05-01

    Recent studies have revealed the presence of TMPRSS2-ERG gene fusion in both primary and metastatic prostate cancers. However, the relationship between primary and corresponding metastatic prostate cancers with respect to the status of this gene fusion remains unclear. Using fluorescence in situ hybridization, we evaluated the rearrangement of the ERG gene in the radical prostatectomy specimens and corresponding lymph node metastases from 19 patients with prostate cancer. The mean age of the patients was 61 years, and the median Gleason score in the radical prostatectomy specimens was 7 (4 + 3). Prostate cancer was unifocal in 6 cases and multifocal in 13 cases, including 10 with 2 foci and 3 with 3 foci. In the primary prostate cancers, rearrangement of the ERG gene was observed in 13 cases and associated with deletion of the 5' ERG gene in 8 cases. In the metastases, the ERG rearrangement was present in 10 cases and associated with deletion of the 5' ERG gene in 6 cases. In unifocal prostate cancers, the status of the ERG rearrangement was concordant between the primary prostate cancer and metastasis in 5 of 6 cases. In multifocal prostate cancer, despite a significant interfocal discordance, the status of the ERG rearrangement was concordant between the index (largest) primary tumor focus and metastasis in all 13 cases. Our study demonstrates a close relationship of the TMPRSS2-ERG gene fusion status between primary and metastatic prostate cancer. The concordance of the ERG gene rearrangement status between the index primary tumor focus and metastasis suggests that metastasis most likely arises from the index tumor focus in multifocal prostate cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. FR171456 is a specific inhibitor of mammalian NSDHL and yeast Erg26p

    PubMed Central

    Helliwell, Stephen B.; Karkare, Shantanu; Bergdoll, Marc; Rahier, Alain; Leighton-Davis, Juliet R.; Fioretto, Celine; Aust, Thomas; Filipuzzi, Ireos; Frederiksen, Mathias; Gounarides, John; Hoepfner, Dominic; Hofmann, Andreas; Imbert, Pierre-Eloi; Jeker, Rolf; Knochenmuss, Richard; Krastel, Philipp; Margerit, Anais; Memmert, Klaus; Miault, Charlotte V.; Rao Movva, N.; Muller, Alban; Naegeli, Hans-Ulrich; Oberer, Lukas; Prindle, Vivian; Riedl, Ralph; Schuierer, Sven; Sexton, Jessica A.; Tao, Jianshi; Wagner, Trixie; Yin, Hong; Zhang, Juan; Roggo, Silvio; Reinker, Stefan; Parker, Christian N.

    2015-01-01

    FR171456 is a natural product with cholesterol-lowering properties in animal models, but its molecular target is unknown, which hinders further drug development. Here we show that FR171456 specifically targets the sterol-4-alpha-carboxylate-3-dehydrogenase (Saccharomyces cerevisiae—Erg26p, Homo sapiens—NSDHL (NAD(P) dependent steroid dehydrogenase-like)), an essential enzyme in the ergosterol/cholesterol biosynthesis pathway. FR171456 significantly alters the levels of cholesterol pathway intermediates in human and yeast cells. Genome-wide yeast haploinsufficiency profiling experiments highlight the erg26/ERG26 strain, and multiple mutations in ERG26 confer resistance to FR171456 in growth and enzyme assays. Some of these ERG26 mutations likely alter Erg26 binding to FR171456, based on a model of Erg26. Finally, we show that FR171456 inhibits an artificial Hepatitis C viral replicon, and has broad antifungal activity, suggesting potential additional utility as an anti-infective. The discovery of the target and binding site of FR171456 within the target will aid further development of this compound. PMID:26456460

  8. Rab11-dependent Recycling of the Human Ether-a-go-go-related Gene (hERG) Channel*

    PubMed Central

    Chen, Jeffery; Guo, Jun; Yang, Tonghua; Li, Wentao; Lamothe, Shawn M.; Kang, Yudi; Szendrey, John A.; Zhang, Shetuan

    2015-01-01

    The human ether-a-go-go-related gene (hERG) encodes the pore-forming subunit of the rapidly activating delayed rectifier potassium channel (IKr). A reduction in the hERG current causes long QT syndrome, which predisposes affected individuals to ventricular arrhythmias and sudden death. We reported previously that hERG channels in the plasma membrane undergo vigorous internalization under low K+ conditions. In the present study, we addressed whether hERG internalization occurs under normal K+ conditions and whether/how internalized channels are recycled back to the plasma membrane. Using patch clamp, Western blot, and confocal imaging analyses, we demonstrated that internalized hERG channels can effectively recycle back to the plasma membrane. Low K+-enhanced hERG internalization is accompanied by an increased rate of hERG recovery in the plasma membrane upon reculture following proteinase K-mediated clearance of cell-surface proteins. The increased recovery rate is not due to enhanced protein synthesis, as hERG mRNA expression was not altered by low K+ exposure, and the increased recovery was observed in the presence of the protein biosynthesis inhibitor cycloheximide. GTPase Rab11, but not Rab4, is involved in the recycling of hERG channels. Interfering with Rab11 function not only delayed hERG recovery in cells after exposure to low K+ medium but also decreased hERG expression and function in cells under normal culture conditions. We concluded that the recycling pathway plays an important role in the homeostasis of plasma membrane-bound hERG channels. PMID:26152716

  9. In vitro chronic effects on hERG channel caused by the marine biotoxin Azaspiracid-2

    PubMed Central

    Ferreiro, Sara F.; Vilariño, Natalia; Louzao, M.Carmen; Nicolaou, K. C.; Frederick, Michael O.; Botana, Luis M.

    2014-01-01

    Azaspiracids (AZAs) are marine biotoxins produced by the dinoflagellate Azadinium spinosum that accumulate in many shellfish species. Azaspiracid poisoning caused by AZA-contaminated seafood consumption is primarily manifested by diarrhea in humans. To protect human health, AZA-1, AZA-2 and AZA-3 content in seafood has been regulated by food safety authorities in many countries. Recently AZAs have been reported as a low/moderate hERG channel blockers. Furthermore AZA-2 has been related to arrhythmia appearance in rats, suggesting potential heart toxicity. In this study AZA-2 in vitro effects on hERG channel after chronic exposure are analyzed to further explore potential cardiotoxicity. The amount of hERG channel in the plasma membrane, hERG channel trafficking and hERG currents were evaluated up to 12 h of toxin exposure. In these conditions AZA-2 caused an increase of hERG levels in the plasma membrane, probably related to hERG retrograde trafficking impairment. Although this alteration did not translate into an increase of hERG channel-related current, more studies will be necessary to understand its mechanism and to know what consequences could have in vivo. These findings suggest that azaspiracids might have chronic cardiotoxicity related to hERG channel trafficking and they should not be overlooked when evaluating the threat to human health. PMID:25286396

  10. Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and Caucasian Americans

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-13-2-0096 TITLE: Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and...Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and Caucasian Americans Sb. GRANT NUMBER W81 XWH-13-2...differences in the distribution of key clinico-pathologic patient features and molecular determinants for both ERG positive and ERG negative prostate cancer

  11. Simulation of background from low-level tritium and radon emanation in the KATRIN spectrometers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leiber, B.; Collaboration: KATRIN Collaboration

    The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment for the model independent determination of the mass of electron anti-neutrinos with a sensitivity of 200 meV/c{sup 2}. It investigates the kinematics of electrons from tritium beta decay close to the endpoint of the energy spectrum at 18.6 keV. To achieve a good signal to background ratio at the endpoint, a low background rate below 10{sup −2} counts per second is required. The KATRIN setup thus consists of a high luminosity windowless gaseous tritium source (WGTS), a magnetic electron transport system with differential and cryogenic pumping for tritium retention, andmore » electro-static retarding spectrometers (pre-spectrometer and main spectrometer) for energy analysis, followed by a segmented detector system for counting transmitted beta-electrons. A major source of background comes from magnetically trapped electrons in the main spectrometer (vacuum vessel: 1240 m{sup 3}, 10{sup −11} mbar) produced by nuclear decays in the magnetic flux tube of the spectrometer. Major contributions are expected from short-lived radon isotopes and tritium. Primary electrons, originating from these decays, can be trapped for hours, until having lost almost all their energy through inelastic scattering on residual gas particles. Depending on the initial energy of the primary electron, up to hundreds of low energetic secondary electrons can be produced. Leaving the spectrometer, these electrons will contribute to the background rate. This contribution describes results from simulations for the various background sources. Decays of {sup 219}Rn, emanating from the main vacuum pump, and tritium from the WGTS that reaches the spectrometers are expected to account for most of the background. As a result of the radon alpha decay, electrons are emitted through various processes, such as shake-off, internal conversion and the Auger deexcitations. The corresponding simulations were done using the

  12. TMPRSS2-ERG gene fusion status in minute (minimal) prostatic adenocarcinoma.

    PubMed

    Albadine, Roula; Latour, Mathieu; Toubaji, Antoun; Haffner, Michael; Isaacs, William B; A Platz, Elizabeth; Meeker, Alan K; Demarzo, Angelo M; Epstein, Jonathan I; Netto, George J

    2009-11-01

    Minute prostatic adenocarcinomas are considered to be of insufficient virulence. Given recent suggestions of TMPRSS2-ERG gene fusion association with aggressive prostatic adenocarcinoma, we evaluated the incidence of TMPRSS2-ERG fusion in minute prostatic adenocarcinomas. A total of 45 consecutive prostatectomies with minute adenocarcinoma were used for tissue microarray construction. A total of 63 consecutive non-minimal, Gleason Score 6 tumors, from a separate PSA Era prostatectomy tissue microarray, were used for comparison. FISH was carried out using ERG break-apart probes. Tumors were assessed for fusion by deletion (Edel) or split (Esplit), duplicated fusions and low-level copy number gain in normal ERG gene locus. Minute adenocarcinomas: Fusion was evaluable in 32/45 tumors (71%). Fifteen out of 32 (47%) tumors were positive for fusion. Six (19%) were of the Edel class and 7 (22%) were classified as combined Edel+Esplit. Non-minute adenocarcinomas (pT2): Fusion was identified in 20/30 tumors (67%). Four (13%) were of Edel class and 5 (17%) were combined Edel+Esplit. Duplicated fusions were encountered in 5 (16%) tumors. Non-minute adenocarcinomas (pT3): Fusion was identified in 19/33 (58%). Fusion was due to a deletion in 6 (18%) tumors. Seven tumors (21%) were classified as combined Edel+Esplit. One tumor showed Esplit alone. Duplicated fusions were encountered in 3 (9%) cases. The incidence of duplicated fusions was higher in non-minute adenocarcinomas (13 vs 0%; P=0.03). A trend for higher incidence of low-level copy number gain in normal ERG gene locus without fusion was noted in non-minute adenocarcinomas (10 vs 0%; P=0.07). We found a TMPRSS2-ERG fusion rate of 47% in minute adenocarcinomas. The latter is not significantly different from that of grade matched non-minute adenocarcinomas. The incidence of duplicated fusion was higher in non-minute adenocarcinomas. Our finding of comparable rate of TMPRSS2-ERG fusion in minute adenocarcinomas may argue

  13. External protons destabilize the activated voltage sensor in hERG channels.

    PubMed

    Shi, Yu Patrick; Cheng, Yen May; Van Slyke, Aaron C; Claydon, Tom W

    2014-03-01

    Extracellular acidosis shifts hERG channel activation to more depolarized potentials and accelerates channel deactivation; however, the mechanisms underlying these effects are unclear. External divalent cations, e.g., Ca(2+) and Cd(2+), mimic these effects and coordinate within a metal ion binding pocket composed of three acidic residues in hERG: D456 and D460 in S2 and D509 in S3. A common mechanism may underlie divalent cation and proton effects on hERG gating. Using two-electrode voltage clamp, we show proton sensitivity of hERG channel activation (pKa = 5.6), but not deactivation, was greatly reduced in the presence of Cd(2+) (0.1 mM), suggesting a common binding site for the Cd(2+) and proton effect on activation and separable effects of protons on activation and deactivation. Mutational analysis confirmed that D509 plays a critical role in the pH dependence of activation, as shown previously, and that cooperative actions involving D456 and D460 are also required. Importantly, neutralization of all three acidic residues abolished the proton-induced shift of activation, suggesting that the metal ion binding pocket alone accounts for the effects of protons on hERG channel activation. Voltage-clamp fluorimetry measurements demonstrated that protons shifted the voltage dependence of S4 movement to more depolarized potentials. The data indicate a site and mechanism of action for protons on hERG activation gating; protonation of D456, D460 and D509 disrupts interactions between these residues and S4 gating charges to destabilize the activated configuration of S4.

  14. The oncogenic gene fusion TMPRSS2: ERG is not a diagnostic or prognostic marker for ovarian cancer

    PubMed Central

    Huang, Lillian; Schauer, Isaiah G; Zhang, Jing; Mercado-Uribe, Imelda; Deavers, Michael T; Huang, Jiaoti; Liu, Jinsong

    2011-01-01

    TMPRSS2:ERG is a gene fusion resulting from the chromosomal rearrangement of the androgen-regulated TMPRSS2 gene and the ETS transcription factor ERG, leading to the over-expression of the oncogenic molecule ERG. This gene rearrangement has been found in approximately half of all prostate cancers and ERG overexpression is considered as a novel diagnostic marker for prostate carcinoma. However, little is known about the role of the TMPRSS2:ERG gene fusion in ovarian cancer. The purpose of this study was to test ERG expression in ovarian cancer and its potential as a diagnostic marker for ovarian carcinoma progression. A tissue microarray containing 180 ovarian cancer tissues of various pathological types and grades were examined by immunohistochemical analysis for expression of ERG. We also used 40 prostate carcinoma tissues and 40 normal tissues for comparison in parallel experiments. ERG-positive expression was detected in 40% of the prostate tumor cancer, as well as in internal positive control endothelial cells, confirming over-expression of ERG in prostate cancer at relatively the same rate observed by others. In contrast, all of the ovarian tumor patient tissues of varying histologic types were ERG-negative, despite some positivity in endothelial cells. These results suggest that the oncogenic gene fusion TMPRSS2:ERG does not occur in ovarian cancer relative to prostate cancer. Therefore, development of ERG expression profile would not be a useful diagnostic or prognostic marker for ovarian cancer patient screening. PMID:22076164

  15. The oncogenic gene fusion TMPRSS2: ERG is not a diagnostic or prognostic marker for ovarian cancer.

    PubMed

    Huang, Lillian; Schauer, Isaiah G; Zhang, Jing; Mercado-Uribe, Imelda; Deavers, Michael T; Huang, Jiaoti; Liu, Jinsong

    2011-01-01

    TMPRSS2:ERG is a gene fusion resulting from the chromosomal rearrangement of the androgen-regulated TMPRSS2 gene and the ETS transcription factor ERG, leading to the over-expression of the oncogenic molecule ERG. This gene rearrangement has been found in approximately half of all prostate cancers and ERG overexpression is considered as a novel diagnostic marker for prostate carcinoma. However, little is known about the role of the TMPRSS2:ERG gene fusion in ovarian cancer. The purpose of this study was to test ERG expression in ovarian cancer and its potential as a diagnostic marker for ovarian carcinoma progression. A tissue microarray containing 180 ovarian cancer tissues of various pathological types and grades were examined by immunohistochemical analysis for expression of ERG. We also used 40 prostate carcinoma tissues and 40 normal tissues for comparison in parallel experiments. ERG-positive expression was detected in 40% of the prostate tumor cancer, as well as in internal positive control endothelial cells, confirming over-expression of ERG in prostate cancer at relatively the same rate observed by others. In contrast, all of the ovarian tumor patient tissues of varying histologic types were ERG-negative, despite some positivity in endothelial cells. These results suggest that the oncogenic gene fusion TMPRSS2:ERG does not occur in ovarian cancer relative to prostate cancer. Therefore, development of ERG expression profile would not be a useful diagnostic or prognostic marker for ovarian cancer patient screening.

  16. Dynamic regulation of VEGF-inducible genes by an ERK/ERG/p300 transcriptional network.

    PubMed

    Fish, Jason E; Cantu Gutierrez, Manuel; Dang, Lan T; Khyzha, Nadiya; Chen, Zhiqi; Veitch, Shawn; Cheng, Henry S; Khor, Melvin; Antounians, Lina; Njock, Makon-Sébastien; Boudreau, Emilie; Herman, Alexander M; Rhyner, Alexander M; Ruiz, Oscar E; Eisenhoffer, George T; Medina-Rivera, Alejandra; Wilson, Michael D; Wythe, Joshua D

    2017-07-01

    The transcriptional pathways activated downstream of vascular endothelial growth factor (VEGF) signaling during angiogenesis remain incompletely characterized. By assessing the signals responsible for induction of the Notch ligand delta-like 4 (DLL4) in endothelial cells, we find that activation of the MAPK/ERK pathway mirrors the rapid and dynamic induction of DLL4 transcription and that this pathway is required for DLL4 expression. Furthermore, VEGF/ERK signaling induces phosphorylation and activation of the ETS transcription factor ERG, a prerequisite for DLL4 induction. Transcription of DLL4 coincides with dynamic ERG-dependent recruitment of the transcriptional co-activator p300. Genome-wide gene expression profiling identified a network of VEGF-responsive and ERG-dependent genes, and ERG chromatin immunoprecipitation (ChIP)-seq revealed the presence of conserved ERG-bound putative enhancer elements near these target genes. Functional experiments performed in vitro and in vivo confirm that this network of genes requires ERK, ERG and p300 activity. Finally, genome-editing and transgenic approaches demonstrate that a highly conserved ERG-bound enhancer located upstream of HLX (which encodes a transcription factor implicated in sprouting angiogenesis) is required for its VEGF-mediated induction. Collectively, these findings elucidate a novel transcriptional pathway contributing to VEGF-dependent angiogenesis. © 2017. Published by The Company of Biologists Ltd.

  17. Oncogenicity and Selective Inhibition of ERG Splicing Variants in Prostate Cancer

    DTIC Science & Technology

    2010-09-01

    cancer specific TMPRSS2-ERG gene fusion products RNA Society’s 2010 Annual Meeting, Seattle, (2010). A manuscript is in preparation and planned for...21 and comparison with the region of conserved synteny on mouse chromosome 16. Gene, 2004. 324: p. 65-77. 20. Carrere , S., et al., Erg proteins

  18. RNA interference targeting E637K mutation rescues hERG channel currents and restores its kinetic properties.

    PubMed

    Lu, Xiaoli; Yang, Xi; Huang, Xiaoyan; Huang, Chen; Sun, Huan Huan; Jin, Lihua; Xu, Weifeng; Mao, Haiyan; Guo, Junming; Zhou, Jianqing; Lian, Jiangfang

    2013-01-01

    Long QT syndrome (LQTS) is a monogenic proarrhythmic disorder that predisposes affected individuals to sudden death from tachyarrhythmia. As an inherited disease, LQTS cannot be completely cured by conventional treatment modalities. Individualized gene therapy is a promising therapeutic approach. The purpose of this study was to investigate the role of small interference RNA (siRNA) on expression of E637K-hERG (human ether-a-go-go-related gene) mutant and whether it can be used to rescue the mutant's dominant-negative suppressive effects on hERG protein channel function. Western blot was performed to select the most sensitive siRNAs to target E637K-hERG mutant knockdown. Confocal laser scanning microscope was performed to monitor cellular localization of wild-type (WT)-hERG and E637K-hERG with or without siRNA. Patch-clamp technique was used to assess the effect of siRNA on the electrophysiologic characteristics of the rapidly activating delayed rectifier K(+) current I(Kr) of the hERG protein channel. siRNA led to a significant decrease in the level of E637K-hERG protein but did not affect the level of WT-hERG protein. WT-hERG localization in cells coexpressing E637K-hERG mutant was restored to the membrane by siRNA. The siRNA-mediated inhibition of E637K-hERG mutant restored the maximum current and tail current amplitudes. Furthermore, siRNA treatment rescued the kinetic properties of WT/E637K-hERG protein channel to a level comparable to that of WT-hERG protein channel. Our findings illustrated that siRNA can effectively inhibit E637K-hERG protein expression and rescue the dominant-negative effect of this mutation by restoring the kinetic properties of hERG protein channel. It has potential clinical implications with regard to the possibility of using siRNA in the treatment of LQTS. Copyright © 2013 Heart Rhythm Society. All rights reserved.

  19. Endocytosis of hERG Is Clathrin-Independent and Involves Arf6

    PubMed Central

    Abuarab, Nada; Smith, Andrew J.; Hardy, Matthew E. L.; Elliott, David J. S.; Sivaprasadarao, Asipu

    2013-01-01

    The hERG potassium channel is critical for repolarisation of the cardiac action potential. Reduced expression of hERG at the plasma membrane, whether caused by hereditary mutations or drugs, results in long QT syndrome and increases the risk of ventricular arrhythmias. Thus, it is of fundamental importance to understand how the density of this channel at the plasma membrane is regulated. We used antibodies to an extracellular native or engineered epitope, in conjunction with immunofluorescence and ELISA, to investigate the mechanism of hERG endocytosis in recombinant cells and validated the findings in rat neonatal cardiac myocytes. The data reveal that this channel undergoes rapid internalisation, which is inhibited by neither dynasore, an inhibitor of dynamin, nor a dominant negative construct of Rab5a, into endosomes that are largely devoid of the transferrin receptor. These results support a clathrin-independent mechanism of endocytosis and exclude involvement of dynamin-dependent caveolin and RhoA mechanisms. In agreement, internalised hERG displayed marked overlap with glycosylphosphatidylinositol-anchored GFP, a clathrin-independent cargo. Endocytosis was significantly affected by cholesterol extraction with methyl-β-cyclodextrin and inhibition of Arf6 function with dominant negative Arf6-T27N-eGFP. Taken together, we conclude that hERG undergoes clathrin-independent endocytosis via a mechanism involving Arf6. PMID:24392021

  20. Towards a Structural View of Drug Binding to hERG K+ Channels.

    PubMed

    Vandenberg, Jamie I; Perozo, Eduardo; Allen, Toby W

    2017-10-01

    The human ether-a-go-go-related gene (hERG) K + channel is of great medical and pharmaceutical relevance. Inherited mutations in hERG result in congenital long-QT syndrome which is associated with a markedly increased risk of cardiac arrhythmia and sudden death. hERG K + channels are also remarkably susceptible to block by a wide range of drugs, which in turn can cause drug-induced long-QT syndrome and an increased risk of sudden death. The recent determination of the near-atomic resolution structure of the hERG K + channel, using single-particle cryo-electron microscopy (cryo-EM), provides tremendous insights into how these channels work. It also suggests a way forward in our quest to understand why these channels are so promiscuous with respect to drug binding. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. [ERG diagnosis and differential diagnosis: results of examination over 6 years].

    PubMed

    Stemeyer, G; Stähli, P

    1996-05-01

    This study reviews the patient material first from the point of view of referral diagnosis. Secondly, we focus on difficulties in selective differential diagnoses. 1501 patients underwent electroretinographic (ERG) testing from 1989 to 1994, amounting to 1815 ERG recordings, including follow-up examinations. The technique applied is full-field, single flash ERG with selective stimulation of the rod- and of the cone-systems. In 3.8% (57 cases) the ERG was performed under general anesthesia in outpatients. Tapetoretinal degenerations, toxic retinal side effects, inflammatory disease and ocular trauma represented, in this order, the major groups of referral diagnoses aside from unclear visual loss. The documentation or the exclusion of tapetoretinal degeneration represented the largest share (57%) of the application of the diagnostic procedure. 171 cases of isolated retinitis pigmentosa (RP) and 33 cases of syndromic RP were identified. Frequent and rare diagnostic entities and their differential diagnoses within this group are discussed. Inevitably, a number of diagnostic decisions remain problematic, in particular at the first examination. These diagnostic difficulties are addressed also and include the differentiation between RP sine pigmento and congenital amaurosis Leber in infants, RP with macular involvement vs. cone-rod degeneration, unilateral RP vs. postinflammatory conditions, and progressive cone dystrophy vs. achromatopsia, cone-rod degeneration or Stargardt's disease. Frequent and meaningful indications for ERG recording and difficult diagnostic decisions arise from this review of a relatively large group of patients. A number of diagnoses can hardly, if not at all be established without ERG testing. These include retinal cause of visual loss in infants, congenital amaurosis Leber, RP sine pigmento, early stages of RP, carrier status in XL RP and in choroideremia, progressive cone dystrophy, toxic retinopathy without fundus changes, retinal involvement

  2. ERG signaling in prostate cancer is driven through PRMT5-dependent methylation of the Androgen Receptor.

    PubMed

    Mounir, Zineb; Korn, Joshua M; Westerling, Thomas; Lin, Fallon; Kirby, Christina A; Schirle, Markus; McAllister, Gregg; Hoffman, Greg; Ramadan, Nadire; Hartung, Anke; Feng, Yan; Kipp, David Randal; Quinn, Christopher; Fodor, Michelle; Baird, Jason; Schoumacher, Marie; Meyer, Ronald; Deeds, James; Buchwalter, Gilles; Stams, Travis; Keen, Nicholas; Sellers, William R; Brown, Myles; Pagliarini, Raymond A

    2016-05-16

    The TMPRSS2:ERG gene fusion is common in androgen receptor (AR) positive prostate cancers, yet its function remains poorly understood. From a screen for functionally relevant ERG interactors, we identify the arginine methyltransferase PRMT5. ERG recruits PRMT5 to AR-target genes, where PRMT5 methylates AR on arginine 761. This attenuates AR recruitment and transcription of genes expressed in differentiated prostate epithelium. The AR-inhibitory function of PRMT5 is restricted to TMPRSS2:ERG-positive prostate cancer cells. Mutation of this methylation site on AR results in a transcriptionally hyperactive AR, suggesting that the proliferative effects of ERG and PRMT5 are mediated through attenuating AR's ability to induce genes normally involved in lineage differentiation. This provides a rationale for targeting PRMT5 in TMPRSS2:ERG positive prostate cancers. Moreover, methylation of AR at arginine 761 highlights a mechanism for how the ERG oncogene may coax AR towards inducing proliferation versus differentiation.

  3. ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones

    PubMed Central

    Pessia, Mauro; Servettini, Ilenio; Panichi, Roberto; Guasti, Leonardo; Grassi, Silvarosa; Arcangeli, Annarosa; Wanke, Enzo; Pettorossi, Vito Enrico

    2008-01-01

    The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage-gated K+ channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike-generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro, by analysing the spontaneous discharge and the response to square-, ramp- and sinusoid-like intracellular DC current injections in extracellular and whole-cell patch-clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY-123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike-frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid-like current, ERG channel block caused frequency-dependent gain enhancement and phase-lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties. PMID:18718985

  4. ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones.

    PubMed

    Pessia, Mauro; Servettini, Ilenio; Panichi, Roberto; Guasti, Leonardo; Grassi, Silvarosa; Arcangeli, Annarosa; Wanke, Enzo; Pettorossi, Vito Enrico

    2008-10-15

    The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage-gated K(+) channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike-generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro, by analysing the spontaneous discharge and the response to square-, ramp- and sinusoid-like intracellular DC current injections in extracellular and whole-cell patch-clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY-123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike-frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid-like current, ERG channel block caused frequency-dependent gain enhancement and phase-lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties.

  5. Interaction among hERG channel blockers is a potential mechanism of death in caffeine overdose.

    PubMed

    Zheng, Jifeng; Zhao, Wei; Xu, Kai; Chen, Qingmao; Chen, Yingying; Shen, Yueliang; Xiao, Liping; Jiang, Liqin; Chen, Yuan

    2017-04-05

    Caffeine overdose death is due to cardiac arrest, but its mechanism has not been explored in detail. In this study, our data showed that caffeine significantly prolonged the heart rate-corrected QT interval (QTc) of rabbits in vivo (P<0.05; n=7). Caffeine was also found to be a hERG channel blocker with an IC 50 of 5.04mM (n=5). Although these two findings likely link caffeine overdose death with hERG channel blockade, the amount of caffeine consumption needed to reach the IC 50 is very high. Further study demonstrated that addition another hERG blocker could lower the consumption of caffeine significantly, no matter whether two hERG blockers share the same binding sites. Our data does not rule out other possibility, however, it suggests that there is a potential causal relationship between caffeine overdose death with hERG channel and the interaction among these hERG blockers. Published by Elsevier B.V.

  6. Assessment of the Absolute Excitatory Level of the Retina by Flicker ERG.

    PubMed

    Tanimoto, Naoyuki; Seeliger, Mathias W

    2018-01-01

    Electroretinography (ERG) is important for functional diagnostics of the retina. Types of information about retinal function obtainable by ERG differ depending on recording conditions, e.g., a combination of light stimulus and adaptation. In terms of stimulation, single-flash and flicker stimuli are frequently used because response properties have been well investigated, allowing an assessment of fundamental retinal functionality; for example, how photoreceptors and bipolar cells, including signal transmission between them, are affected under pathological conditions. Usually, ERGs are recorded with a nonzero lower cutoff frequency of amplifiers to avoid certain artifacts, and additionally, responses are averaged over time so that non-event-related signals are cancelled out. However, the improved signal quality is associated with a loss of information. Especially in steady-state flicker ERG, information about the absolute baseline of recordings is missing because the prestimulus baseline is not included on the recording trace as well as because a zero response is obtained in all cases in which the signal baseline stays constant for a sufficient amount of time. In other words, it is impossible to tell from the conventional flicker ERG whether a zero signal is obtained under conditions of maximal or no excitation of the visual system. In this chapter, we describe a direct current ERG protocol (featuring a lower cutoff frequency of zero) with repetitive single flashes mimicking conventional flicker that contains a defined onset. Using this recording protocol, it is possible to assess not only the absolute excitatory level of the retina but also the development of steady-state responses from the single flash response.

  7. Discovery and characterization of small molecules targeting the DNA-binding ETS domain of ERG in prostate cancer

    PubMed Central

    Kim, Ari; Yen, Paul; Mroczek, Marta; Nouri, Mannan; Lien, Scott; Axerio-Cilies, Peter; Dalal, Kush; Yau, Clement; Ghaidi, Fariba; Guo, Yubin; Yamazaki, Takeshi; Lawn, Sam; Gleave, Martin E.; Gregory-Evans, Cheryl Y.

    2017-01-01

    Genomic alterations involving translocations of the ETS-related gene ERG occur in approximately half of prostate cancer cases. These alterations result in aberrant, androgen-regulated production of ERG protein variants that directly contribute to disease development and progression. This study describes the discovery and characterization of a new class of small molecule ERG antagonists identified through rational in silico methods. These antagonists are designed to sterically block DNA binding by the ETS domain of ERG and thereby disrupt transcriptional activity. We confirmed the direct binding of a lead compound, VPC-18005, with the ERG-ETS domain using biophysical approaches. We then demonstrated VPC-18005 reduced migration and invasion rates of ERG expressing prostate cancer cells, and reduced metastasis in a zebrafish xenograft model. These results demonstrate proof-of-principal that small molecule targeting of the ERG-ETS domain can suppress transcriptional activity and reverse transformed characteristics of prostate cancers aberrantly expressing ERG. Clinical advancement of the developed small molecule inhibitors may provide new therapeutic agents for use as alternatives to, or in combination with, current therapies for men with ERG-expressing metastatic castration-resistant prostate cancer. PMID:28465491

  8. Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and Caucasian Americans

    DTIC Science & Technology

    2014-10-01

    Tomlins SA, Mudaliar KM, et al: Antibody-based detection of ERG rearrangement-positive prostate cancer. Neoplasia 12: 590-598, 2010. 8. Braun M, Goltz D...detection of ERG rearrangement-positive prostate cancer. Neoplasia 12: 590-598, 2010. 16. Braun M, Goltz D, Shaikhibrahim Z, et al: ERG protein

  9. IL-6 Overexpression in ERG-Positive Prostate Cancer Is Mediated by Prostaglandin Receptor EP2.

    PubMed

    Merz, Constanze; von Mässenhausen, Anne; Queisser, Angela; Vogel, Wenzel; Andrén, Ove; Kirfel, Jutta; Duensing, Stefan; Perner, Sven; Nowak, Michael

    2016-04-01

    Prostate cancer is the most diagnosed cancer in men and multiple risk factors and genetic alterations have been described. The TMPRSS2-ERG fusion event and the overexpression of the transcription factor ERG are present in approximately 50% of all prostate cancer patients, however, the clinical outcome is still controversial. Prostate tumors produce various soluble factors, including the pleiotropic cytokine IL-6, regulating cellular processes such as proliferation and metastatic segregation. Here, we used prostatectomy samples in a tissue microarray format and analyzed the co-expression and the clinicopathologic data of ERG and IL-6 using immunohistochemical double staining and correlated the read-out with clinicopathologic data. Expression of ERG and IL-6 correlated strongly in prostate tissue samples. Forced expression of ERG in prostate tumor cell lines resulted in significantly increased secretion of IL-6, whereas the down-regulation of ERG decreased IL-6 secretion. By dissecting the underlying mechanism in prostate tumor cell lines we show the ERG-mediated up-regulation of the prostanoid receptors EP2 and EP3. The prostanoid receptor EP2 was overexpressed in human prostate cancer tissue. Furthermore, the proliferation rate and IL-6 secretion in DU145 cells was reduced after treatment with EP2-receptor antagonist. Collectively, our study shows that the expression of ERG in prostate cancer is linked to the expression of IL-6 mediated by the prostanoid receptor EP2. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  10. A novel assessment of nefazodone-induced hERG inhibition by electrophysiological and stereochemical method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shin, Dae-Seop; Park, Myoung Joo; Lee, Hyang-Ae

    2014-02-01

    Nefazodone was used widely as an antidepressant until it was withdrawn from the U.S. market in 2004 due to hepatotoxicity. We have investigated methods to predict various toxic effects of drug candidates to reduce the failure rate of drug discovery. An electrophysiological method was used to assess the cardiotoxicity of drug candidates. Small molecules, including withdrawn drugs, were evaluated using a patch-clamp method to establish a database of hERG inhibition. Nefazodone inhibited hERG channel activity in our system. However, nefazodone-induced hERG inhibition indicated only a theoretical risk of cardiotoxicity. Nefazodone inhibited the hERG channel in a concentration-dependent manner with anmore » IC{sub 50} of 45.3 nM in HEK-293 cells. Nefazodone accelerated both the recovery from inactivation and its onset. Nefazodone also accelerated steady-state inactivation, although it did not modify the voltage-dependent character. Alanine mutants of hERG S6 and pore region residues were used to identify the nefazodone-binding site on hERG. The hERG S6 point mutants Y652A and F656A largely abolished the inhibition by nefazodone. The pore region mutant S624A mildly reduced the inhibition by nefazodone but T623A had little effect. A docking study showed that the aromatic rings of nefazodone interact with Y652 and F656 via π–π interactions, while an amine interacted with the S624 residue in the pore region. In conclusion, Y652 and F656 in the S6 domain play critical roles in nefazodone binding. - Highlights: • Nefazodone inhibits hERG channels with an IC{sub 50} of 45.3 nM in HEK-293 cells. • Nefazodone blocks hERG channels by binding to the open channels. • Y652 and F656 are important for binding of nefazodone. • The aromatic rings of nefazodone interact with Y652 and F656 via π–π interactions.« less

  11. The hERG K+ channel: target and antitarget strategies in drug development.

    PubMed

    Raschi, Emanuel; Vasina, Valentina; Poluzzi, Elisabetta; De Ponti, Fabrizio

    2008-03-01

    The human ether-à-go-go related gene (hERG) K+ channel is of great interest for both basic researchers and clinicians because its blockade by drugs can lead to QT prolongation, which is a risk factor for torsades de pointes, a potentially life-threatening arrhythmia. A growing list of agents with "QT liability" have been withdrawn from the market or restricted in their use, whereas others did not even receive regulatory approval for this reason. Thus, hERG K+ channels have become a primary antitarget (i.e. an unwanted target) in drug development because their blockade causes potentially serious side effects. On the other hand, the recent identification and functional characterization of hERG K+ channels not only in the heart, but also in several other tissues (e.g. neurons, smooth muscle and cancer cells) may have far reaching implications for drug development for a possible exploitation of hERG as a target, especially in oncology and cardiology.

  12. A Critical Assessment of Combined Ligand-based and Structure-based Approaches to hERG Channel Blocker Modeling

    PubMed Central

    Du-Cuny, Lei; Chen, Lu; Zhang, Shuxing

    2014-01-01

    Blockade of hERG channel prolongs the duration of the cardiac action potential and is a common reason for drug failure in preclinical safety trials. Therefore, it is of great importance to develop robust in silico tools to predict potential hERG blockers in the early stages of drug discovery and development. Herein we described comprehensive approaches to assess the discrimination of hERG-active and -inactive compounds by combining QSAR modeling, pharmacophore analysis, and molecular docking. Our consensus models demonstrated high predictive capacity and improved enrichment, and they could correctly classify 91.8% of 147 hERG blockers from 351 inactives. To further enhance our modeling effort, hERG homology models were constructed and molecular docking studies were conducted, resulting in high correlations (R2=0.81) between predicted and experimental binding affinities. We expect our unique models can be applied to efficient screening for hERG blockades, and our extensive understanding of the hERG-inhibitor interactions will facilitate the rational design of drugs devoid of hERG channel activity and hence with reduced cardiac toxicities. PMID:21902220

  13. Case of paraneoplastic retinopathy with retinal ON-bipolar cell dysfunction and subsequent resolution of ERGs.

    PubMed

    Ueno, Shinji; Nakanishi, Ayami; Nishi, Kayo; Suzuki, Shiro; Terasaki, Hiroko

    2015-02-01

    To report a patient with cancer-associated retinopathy and retinal ON-bipolar cell dysfunction who had a resolution of the electroretinograms (ERGs) after a resection of an ovarian cancer and chemotherapy. A 71-year-old Japanese female patient visited us complaining of night blindness and photopsia in both eyes for 6 months. Her visual acuity was 20/20 in both eyes, and fundus examination, fluorescence angiography, and optical coherence tomography showed no abnormalities in both eyes. The rod responses of the ERGs were absent and bright-flash ERGs were electronegative. The ON responses of the focal macular ERGs and full-field long-flash ERGs were absent. These ERG findings indicate an ON-bipolar cell dysfunction. A general physical examination revealed the presence of ovarian cancer. After resection of the ovarian cancer and adjuvant chemotherapy, the ERGs of the left eye completely recovered within 2 years and those of right eye recovered subsequently. The autoantibody against transient receptor potential melastatin 1 (TRPM1) was not detected in the serum. Our case demonstrates that retinal ON-bipolar dysfunction can be caused by ovarian cancer. Our case indicates that some autoantibodies against other than TRPM1 might cause transient dysfunction of retinal ON-bipolar cells.

  14. Mechanism of hERG channel block by the psychoactive indole alkaloid ibogaine.

    PubMed

    Thurner, Patrick; Stary-Weinzinger, Anna; Gafar, Hend; Gawali, Vaibhavkumar S; Kudlacek, Oliver; Zezula, Juergen; Hilber, Karlheinz; Boehm, Stefan; Sandtner, Walter; Koenig, Xaver

    2014-02-01

    Ibogaine is a psychoactive indole alkaloid. Its use as an antiaddictive agent has been accompanied by QT prolongation and cardiac arrhythmias, which are most likely caused by human ether a go-go-related gene (hERG) potassium channel inhibition. Therefore, we studied in detail the interaction of ibogaine with hERG channels heterologously expressed in mammalian kidney tsA-201 cells. Currents through hERG channels were blocked regardless of whether ibogaine was applied via the extracellular or intracellular solution. The extent of inhibition was determined by the relative pH values. Block occurred during activation of the channels and was not observed for resting channels. With increasing depolarizations, ibogaine block grew and developed faster. Steady-state activation and inactivation of the channel were shifted to more negative potentials. Deactivation was slowed, whereas inactivation was accelerated. Mutations in the binding site reported for other hERG channel blockers (Y652A and F656A) reduced the potency of ibogaine, whereas an inactivation-deficient double mutant (G628C/S631C) was as sensitive as wild-type channels. Molecular drug docking indicated binding within the inner cavity of the channel independently of the protonation of ibogaine. Experimental current traces were fit to a kinetic model of hERG channel gating, revealing preferential binding of ibogaine to the open and inactivated state. Taken together, these findings show that ibogaine blocks hERG channels from the cytosolic side either in its charged form alone or in company with its uncharged form and alters the currents by changing the relative contribution of channel states over time.

  15. Stereoselective Inhibition of the hERG1 Potassium Channel

    PubMed Central

    Grilo, Liliana Sintra; Carrupt, Pierre-Alain; Abriel, Hugues

    2010-01-01

    A growing number of drugs have been shown to prolong cardiac repolarization, predisposing individuals to life-threatening ventricular arrhythmias known as Torsades de Pointes. Most of these drugs are known to interfere with the human ether à-gogo related gene 1 (hERG1) channel, whose current is one of the main determinants of action potential duration. Prolonged repolarization is reflected by lengthening of the QT interval of the electrocardiogram, as seen in the suitably named drug-induced long QT syndrome. Chirality (presence of an asymmetric atom) is a common feature of marketed drugs, which can therefore exist in at least two enantiomers with distinct three-dimensional structures and possibly distinct biological fates. Both the pharmacokinetic and pharmacodynamic properties can differ between enantiomers, as well as also between individuals who take the drug due to metabolic polymorphisms. Despite the large number of reports about drugs reducing the hERG1 current, potential stereoselective contributions have only been scarcely investigated. In this review, we present a non-exhaustive list of clinically important molecules which display chiral toxicity that may be related to hERG1-blocking properties. We particularly focus on methadone cardiotoxicity, which illustrates the importance of the stereoselective effect of drug chirality as well as individual variations resulting from pharmacogenetics. Furthermore, it seems likely that, during drug development, consideration of chirality in lead optimization and systematic assessment of the hERG1 current block with all enantiomers could contribute to the reduction of the risk of drug-induced LQTS. PMID:21833176

  16. North Polar Erg

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    This VIS image was taken at 81 degrees North latitude during Northern spring. This region of the north polar erg is dominated by a different form of dunes than yesterday's image.

    Image information: VIS instrument. Latitude 81.4, Longitude 121.9 East (238.1 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. The Windowless Gaseous Tritium Source (WGTS) of the KATRIN experiment

    NASA Astrophysics Data System (ADS)

    Heizmann, Florian; Seitz-Moskaliuk, Hendrik; KATRIN Collaboration

    2017-09-01

    The Karlsruhe Tritium Neutrino Experiment (KATRIN) will perform a direct, kinematics-based measurement of the neutrino mass with a sensitivity of 200 meV (90 % C. L.), which will be reached after 3 years of measurement time. The neutrino mass is obtained by investigating the shape of the energy spectrum of tritium β-decay electrons close to the endpoint at 18.6 keV with a spectrometer of MAC-E filter type. This contribution reviews the current status of the tritium source cryostat and magnet system which is currently in its first cool-down phase. Furthermore, the next steps of the comprehensive pre-tritium measurement programme to characterise the apparatus and investigate important systematics are outlined. This work is supported by BMBF (05A14VK2) and the Helmholtz Association.

  18. Advance in ERG Analysis: From Peak Time and Amplitude to Frequency, Power, and Energy

    PubMed Central

    Lina, Jean-Marc; Lachapelle, Pierre

    2014-01-01

    Purpose. To compare time domain (TD: peak time and amplitude) analysis of the human photopic electroretinogram (ERG) with measures obtained in the frequency domain (Fourier analysis: FA) and in the time-frequency domain (continuous (CWT) and discrete (DWT) wavelet transforms). Methods. Normal ERGs (n = 40) were analyzed using traditional peak time and amplitude measurements of the a- and b-waves in the TD and descriptors extracted from FA, CWT, and DWT. Selected descriptors were also compared in their ability to monitor the long-term consequences of disease process. Results. Each method extracted relevant information but had distinct limitations (i.e., temporal and frequency resolutions). The DWT offered the best compromise by allowing us to extract more relevant descriptors of the ERG signal at the cost of lesser temporal and frequency resolutions. Follow-ups of disease progression were more prolonged with the DWT (max 29 years compared to 13 with TD). Conclusions. Standardized time domain analysis of retinal function should be complemented with advanced DWT descriptors of the ERG. This method should allow more sensitive/specific quantifications of ERG responses, facilitate follow-up of disease progression, and identify diagnostically significant changes of ERG waveforms that are not resolved when the analysis is only limited to time domain measurements. PMID:25061605

  19. The amiodarone derivative KB130015 activates hERG1 potassium channels via a novel mechanism

    PubMed Central

    Gessner, Guido; Macianskiene, Regina; Starkus, John G.; Schönherr, Roland; Heinemann, Stefan H.

    2010-01-01

    Human ether à go-go related gene (hERG1) potassium channels underlie the repolarizing IKr current in the heart. Since they are targets of various drugs with cardiac side effects we tested whether the amiodarone derivative 2-methyl-3-(3,5-diiodo-4-carboxymethoxybenzyl)benzofuran (KB130015) blocks hERG1 channels like its parent compound. Using patch-clamp and two-electrode voltage-clamp techniques we found that KB130015 blocks native and recombinant hERG1 channels at high voltages, but it activates them at low voltages. The activating effect has an apparent EC50 value of 12 μM and is brought about by an about 4-fold acceleration of activation kinetics and a shift in voltage-dependent activation by −16 mV. Channel activation was not use-dependent and was independent of inactivation gating. KB130015 presumably binds to the hERG1 pore from the cytosolic side and functionally competes with hERG1 block by amiodarone, E4031 (N-[4-[[1-[2-(6-methyl-2-pyridinyl)ethyl] -4-piperidinyl] carbonyl] phenyl] methanesulfonamide dihydrochloride), and sertindole. Vice versa, amiodarone attenuates hERG1 activation by KB130015. Based on synergic channel activation by mallotoxin and KB130015 we conclude that the hERG1 pore contains at least two sites for activators that are functionally coupled among each other and to the cavity-blocker site. KB130015 and amiodarone may serve as lead structures for the identification of hERG1 pore-interacting drugs favoring channel activation vs. block. PMID:20097192

  20. Small Molecule Inhibitors of ERG and ETV1 in Prostate Cancer

    DTIC Science & Technology

    2016-06-01

    transition associated genes in ERG treated tumors. However, immunohistochemical analyses of these proteins in the tumors of treated and untreated animals...10). We determined that epithelial- mesenchymal transition (EMT) associated proteins RASAL2, VIM, NREP, and BCL11A were decreased among others. ERG...35 and 86.2 xenografts. RNASeq was performed to identify genes that were suppressed by YK-4-279. Epithelial- mesenchymal transition associated

  1. Analytical platform evaluation for quantification of ERG in prostate cancer using protein and mRNA detection methods

    DOE PAGES

    He, Jintang; Schepmoes, Athena A.; Shi, Tujin; ...

    2015-01-01

    Background: The established methods for detecting prostate cancer (CaP) are based on tests using PSA (blood), PCA3 (urine), and AMACR (tissue) as biomarkers in patient samples. The demonstration of ERG oncoprotein overexpression due to gene fusion in CaP has thus provided ERG as an additional biomarker. Based on this, we hypothesized that ERG protein quantification methods can be of use in the diagnosis of prostate cancer. Methods: Therefore, an antibody-free assay for ERG3 protein detection was developed based on PRISM (high-pressure high-resolution separations with intelligent selection and multiplexing)-SRM (selected reaction monitoring) mass spectrometry. We utilized TMPRSS2-ERG positive VCaP and TMPRSS2-ERGmore » negative LNCaP cells to simulate three different sample types (cells, tissue, and post-DRE urine sediment). Results: Recombinant ERG3 protein spiked into LNCaP cell lysates could be detected at levels as low as 20 pg by PRISM-SRM analysis. The sensitivity of the PRISM-SRM assay was around approximately 10,000 VCaP cells in a mixed cell population model of VCaP and LNCaP cells. Interestingly, ERG protein could be detected in as few as 600 VCaP cells spiked into female urine. The sensitivity of the in-house enzyme-linked immunosorbent assay (ELISA) was similar to the PRISM-SRM assay, with detection of 30 pg of purified recombinant ERG3 protein and 10,000 VCaP cells. On the other hand, qRT-PCR exhibited a higher sensitivity, as TMPRSS2-ERG transcripts were detected in as few as 100 VCaP cells, in comparison to NanoString methodologies which detected ERG from 10,000 cells. Conclusions: Based on this data, we propose that the detection of both ERG transcriptional products with RNA-based assays, as well as protein products of ERG using PRISM-SRM assays, may be of clinical value in developing diagnostics and prognostics assays for prostate cancer given their sensitivity, specificity, and reproducibility.« less

  2. [Lead compound optimization strategy(5) – reducing the hERG cardiac toxicity in drug development].

    PubMed

    Zhou, Sheng-bin; Wang, Jiang; Liu, Hong

    2016-10-01

    The potassium channel encoded by the human ether-a-go-go related gene(hERG) plays a very important role in the physiological and pathological processes in human. hERG potassium channel determines the outward currents which facilitate the repolarization of the myocardial cells. Some drugs were withdrawn from the market for the serious side effect of long QT interval and arrhythmia due to blockade of hERG channel. The strategies for lead compound optimization are to reduce inhibitory activity of hERG potassium channel and decrease cardiac toxicity. These methods include reduction of lipophilicity and basicity of amines, introduction of hydroxyl and acidic groups, and restricting conformation.

  3. Manipulation of GES and ERG20 for geraniol overproduction in Saccharomyces cerevisiae.

    PubMed

    Jiang, Guo-Zhen; Yao, Ming-Dong; Wang, Ying; Zhou, Liang; Song, Tian-Qing; Liu, Hong; Xiao, Wen-Hai; Yuan, Ying-Jin

    2017-05-01

    Manipulation of monoterpene synthases to maximize flux towards targeted products from GPP (geranyl diphosphate) is the main challenge for heterologous monoterpene overproduction, in addition to cell toxicity from compounds themselves. In our study, by manipulation of the key enzymes geraniol synthase (GES) and farnesyl diphosphate synthase (Erg20), geraniol (a valuable acyclic monoterpene alcohol) overproduction was achieved in Saccharomyces cerevisiae with truncated 3-hydroxy-3-methylglutaryl-coenzyme reductase (tHMGR) and isopentenyl diphosphate isomerase (IDI1) overexpressed. The expressions of all above engineered genes were under the control of Gal promoter for alleviating product toxicity. Geraniol production varied from trace amount to 43.19mg/L (CrGES, GES from Catharanthus roseus) by screening of nine GESs from diverse species. Further through protein structure analysis and site-directed mutation in CrGES, it was firstly demonstrated that among the high-conserved amino acid residues located in active pocket, Y436 and D501 with strong affinity to diphosphate function group, were critical for the dephosphorylation (the core step for geraniol formation). Moreover, the truncation position of the transit peptide from the N-terminus of CrGES was found to influence protein expression and activity significantly, obtaining a titer of 191.61mg/L geraniol in strain with CrGES truncated at S43 (t3CrGES). Furthermore, directed by surface electrostatics distribution of t3CrGES and Erg20 WW (Erg20 F96W-N127W ), co-expression of the reverse fusion of Erg20 ww /t3CrGES and another copy of Erg20 WW promoted the geraniol titer to 523.96mg/L at shakes flask level, due to enhancing GPP accessibility led by protein interaction of t3CrGES-Erg20 WW and the free Erg20 WW . Eventually, a highest reported titer of 1.68g/L geraniol in eukaryote cells was achieved in 2.0L fed-batch fermentation under carbon restriction strategy. Our research opens large opportunities for other

  4. Investigation of miscellaneous hERG inhibition in large diverse compound collection using automated patch-clamp assay

    PubMed Central

    Yu, Hai-bo; Zou, Bei-yan; Wang, Xiao-liang; Li, Min

    2016-01-01

    Aim: hERG potassium channels display miscellaneous interactions with diverse chemical scaffolds. In this study we assessed the hERG inhibition in a large compound library of diverse chemical entities and provided data for better understanding of the mechanisms underlying promiscuity of hERG inhibition. Methods: Approximately 300 000 compounds contained in Molecular Library Small Molecular Repository (MLSMR) library were tested. Compound profiling was conducted on hERG-CHO cells using the automated patch-clamp platform–IonWorks Quattro™. Results: The compound library was tested at 1 and 10 μmol/L. IC50 values were predicted using a modified 4-parameter logistic model. Inhibitor hits were binned into three groups based on their potency: high (IC50<1 μmol/L), intermediate (1 μmol/L< IC50<10 μmol/L), and low (IC50>10 μmol/L) with hit rates of 1.64%, 9.17% and 16.63%, respectively. Six physiochemical properties of each compound were acquired and calculated using ACD software to evaluate the correlation between hERG inhibition and the properties: hERG inhibition was positively correlative to the physiochemical properties ALogP, molecular weight and RTB, and negatively correlative to TPSA. Conclusion: Based on a large diverse compound collection, this study provides experimental evidence to understand the promiscuity of hERG inhibition. This study further demonstrates that hERG liability compounds tend to be more hydrophobic, high-molecular, flexible and polarizable. PMID:26725739

  5. Targeting TMPRSS2 ERG in Prostate Cancer

    DTIC Science & Technology

    2016-09-01

    Assay development for surface Plasmon resonance with purified ERG protein (months 31-36, completed July 2016) 7c. Perform thermal shift and...surface Plasmon resonance on compounds and determine binding constants (months 37-42, completed July 2016) Task 8. Identify FDA approved drugs that

  6. Automated Patch-Clamp Methods for the hERG Cardiac Potassium Channel.

    PubMed

    Houtmann, Sylvie; Schombert, Brigitte; Sanson, Camille; Partiseti, Michel; Bohme, G Andrees

    2017-01-01

    The human Ether-a-go-go Related Gene (hERG) product has been identified as a central ion channel underlying both familial forms of elongated QT interval on the electrocardiogram and drug-induced elongation of the same QT segment. Indeed, reduced function of this potassium channel involved in the repolarization of the cardiac action potential can produce a type of life-threatening cardiac ventricular arrhythmias called Torsades de Pointes (TdP). Therefore, hERG inhibitory activity of newly synthetized molecules is a relevant structure-activity metric for compound prioritization and optimization in medicinal chemistry phases of drug discovery. Electrophysiology remains the gold standard for the functional assessment of ion channel pharmacology. The recent years have witnessed automatization and parallelization of the manual patch-clamp technique, allowing higher throughput screening on recombinant hERG channels. However, the multi-well plate format of automatized patch-clamp does not allow visual detection of potential micro-precipitation of poorly soluble compounds. In this chapter we describe bench procedures for the culture and preparation of hERG-expressing CHO cells for recording on an automated patch-clamp workstation. We also show that the sensitivity of the assay can be improved by adding a surfactant to the extracellular medium.

  7. Transcription factor ERG and joint and articular cartilage formation during mouse limb and spine skeletogenesis.

    PubMed

    Iwamoto, Masahiro; Tamamura, Yoshihiro; Koyama, Eiki; Komori, Toshihisa; Takeshita, Nobuo; Williams, Julie A; Nakamura, Takashi; Enomoto-Iwamoto, Motomi; Pacifici, Maurizio

    2007-05-01

    Articular cartilage and synovial joints are critical for skeletal function, but the mechanisms regulating their development are largely unknown. In previous studies we found that the ets transcription factor ERG and its alternatively-spliced variant C-1-1 have roles in joint formation in chick. Here, we extended our studies to mouse. We found that ERG is also expressed in developing mouse limb joints. To test regulation of ERG expression, beads coated with the joint master regulator protein GDF-5 were implanted close to incipient joints in mouse limb explants; this led to rapid and strong ectopic ERG expression. We cloned and characterized several mammalian ERG variants and expressed a human C-1-1 counterpart (hERG3Delta81) throughout the cartilaginous skeleton of transgenic mice, using Col2a1 gene promoter/enhancer sequences. The skeletal phenotype was severe and neonatal lethal, and the transgenic mice were smaller than wild type littermates and their skeletons were largely cartilaginous. Limb long bone anlagen were entirely composed of chondrocytes actively expressing collagen IX and aggrecan as well as articular markers such as tenascin-C. Typical growth plates were absent and there was very low expression of maturation and hypertrophy markers, including Indian hedgehog, collagen X and MMP-13. The results suggest that ERG is part of molecular mechanisms leading chondrocytes into a permanent developmental path and become joint forming cells, and may do so by acting downstream of GDF-5.

  8. Imaging Erg and Jun transcription factor interaction in living cells using fluorescence resonance energy transfer analyses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Camuzeaux, Barbara; Spriet, Corentin; Heliot, Laurent

    2005-07-15

    Physical interactions between transcription factors play important roles in modulating gene expression. Previous in vitro studies have shown a transcriptional synergy between Erg protein, an Ets family member, and Jun/Fos heterodimer, members of the bZip family, which requires direct Erg-Jun protein interactions. Visualization of protein interactions in living cells is a new challenge in biology. For this purpose, we generated fusion proteins of Erg, Fos, and Jun with yellow and cyan fluorescent proteins, YFP and CFP, respectively. After transient expression in HeLa cells, interactions of the resulting fusion proteins were explored by fluorescence resonance energy transfer microscopy (FRET) in fixedmore » and living cells. FRET between YFP-Erg and CFP-Jun was monitored by using photobleaching FRET and fluorescence lifetime imaging microscopy. Both techniques revealed the occurrence of intermolecular FRET between YFP-Erg and CFP-Jun. This is stressed by loss of FRET with an YFP-Erg version carrying a point mutation in its ETS domain. These results provide evidence for the interaction of Erg and Jun proteins in living cells as a critical prerequisite of their transcriptional synergy, but also for the essential role of the Y371 residue, conserved in most Ets proteins, in this interaction.« less

  9. Targeting TMPRSS2-ERG in Prostate Cancer

    DTIC Science & Technology

    2017-11-01

    phosphorylated proteins in ERG positive versus negative cell lines following suppression of kinases by shRNA or knockout using CRISPR /Cas9...the cofactor is below detection by silver staining. Future experiments are aimed at generating a stable cell line using CRISPR /Cas9 that has

  10. Structural implications of hERG K+ channel block by a high-affinity minimally structured blocker

    PubMed Central

    Helliwell, Matthew V.; Zhang, Yihong; El Harchi, Aziza; Du, Chunyun; Hancox, Jules C.; Dempsey, Christopher E.

    2018-01-01

    Cardiac potassium channels encoded by human ether-à-go-go–related gene (hERG) are major targets for structurally diverse drugs associated with acquired long QT syndrome. This study characterized hERG channel inhibition by a minimally structured high-affinity hERG inhibitor, Cavalli-2, composed of three phenyl groups linked by polymethylene spacers around a central amino group, chosen to probe the spatial arrangement of side chain groups in the high-affinity drug-binding site of the hERG pore. hERG current (IhERG) recorded at physiological temperature from HEK293 cells was inhibited with an IC50 of 35.6 nm with time and voltage dependence characteristic of blockade contingent upon channel gating. Potency of Cavalli-2 action was markedly reduced for attenuated inactivation mutants located near (S620T; 54-fold) and remote from (N588K; 15-fold) the channel pore. The S6 Y652A and F656A mutations decreased inhibitory potency 17- and 75-fold, respectively, whereas T623A and S624A at the base of the selectivity filter also decreased potency (16- and 7-fold, respectively). The S5 helix F557L mutation decreased potency 10-fold, and both F557L and Y652A mutations eliminated voltage dependence of inhibition. Computational docking using the recent cryo-EM structure of an open channel hERG construct could only partially recapitulate experimental data, and the high dependence of Cavalli-2 block on Phe-656 is not readily explainable in that structure. A small clockwise rotation of the inner (S6) helix of the hERG pore from its configuration in the cryo-EM structure may be required to optimize Phe-656 side chain orientations compatible with high-affinity block. PMID:29545312

  11. Inhibitory action of methadone and its metabolites on erg-mediated K+ current in GH₃ pituitary tumor cells.

    PubMed

    Huang, Mei-Han; Shen, Ai-Yu; Wang, Trey-Shy; Wu, Hui-Ming; Kang, Ya-Fei; Chen, Chia-Tai; Hsu, Tai-I; Chen, Bing-Shuo; Wu, Sheng-Nan

    2011-02-04

    Methadone (Mtd) is a widely used opioid drug associated with the side effect of hyperprolactinemia. The mechanism of how Mtd induces prolactin secretion remains unclear. The effects of Mtd and its two main metabolites (EDDP: (±)-2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium percholarate and EMDP: 2-ethyl-5-methyl-3,3-dipnehyl-1-pyrroline) on ion currents were investigated in GH₃ pituitary tumor cells. Hyperpolarization-elicited K+ currents in GH₃ cells bathed in a high-K(+), Ca(2+)-free solution were studied to evaluate the effects of Mtd and other related compounds on the ether-à-go-go-related-gene (erg) K(+) current (I(K(erg))). Mtd suppressed the amplitude of I(K(erg)) in a concentration-dependent manner with an IC(50) value of 10.4 μM. With the aid of a minimal binding scheme, the inhibitory action of Mtd on I(K(erg)) was estimated with a dissociation constant of 8.2 μM. Mtd tended to increase the rate of I(K(erg)) deactivation in a voltage-dependent fashion. EDDP (10 μM) had no effect on I(K(erg)), while EMDP (10μM) slightly suppressed it. In GH₃ cells incubated with naloxone (30 μM), the Mtd-induced inhibition of I(K(erg)) remained unaltered. Under cell-attached voltage-clamp recordings, Mtd increased the frequency of spontaneous action currents with no change in current amplitude. Similarly, Mtd can suppress I(K(erg)) in differentiated NG108-15 cells; dynorphin A(1-13) did not reverse Mtd-induced inhibition of I(K(erg)). This study shows that Mtd has a depressant effect on I(K(erg)), and suggests its ability to affect membrane excitability and prolactin secretion. The cyclization of Mtd, in which EDDP and EMDP are formed, tends to be critical in removal of the Mtd binding to erg K+ channel. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. [Effects of pressure induced retinal ischemia on ERG in rabbit].

    PubMed

    Song, G; Yang, X; Zhang, Z; Zhang, D

    2001-12-01

    To observe the effects of pressure induced retinal ischemia on electroretinogram(ERG) in rabbit. Retinal ischemia was induced in rabbits by increasing intraocular pressure at 30 mmHg, 60 mmHg, 90 mmHg, 120 mmHg for 45 minutes, and retinal function was monitored by eletroretinography. There was no difference on ERG before or after the experiment both in 30 mmHg group and control one. In 60 mmHg pressure induced ischemia eyes, the amplitudes of the b-wave and OPs wave reduced significantly. Four hours after reperfusion, they were totally recovered. After an ischemic insult of 90 mmHg or 120 mmHg for 45 minutes, there was no response of ERG. Four hours later, the amplitudes of the b-wave and OPs wave were 66.912 +/- 20.157 and 16.423 +/- 3.965 the former, 38.852 +/- 23.438 and 8.610 +/- 12.090 the latter, respectively. These results suggest that higher intraocular pressure causes more severe retina ischemic damage, and less recovery ability.

  13. Thermal inertia and radar reflectivity of the Martian north polar ERG: Low-density aggregates

    NASA Technical Reports Server (NTRS)

    Herkenhoff, K. E.

    1993-01-01

    The north polar layered deposits on Mars appear to be the source of the dark material that comprises the north polar erg. The physical properties and chemical composition of the erg material therefore have important implications for the origin and evolution of the Martian layered deposits. Viking bistatic radar and infrared thermal mapping (IRTM) data indicate that the bulk density of the erg material is lower than that of the average Martian surface. These data are consistent with hypotheses involving formation of filamentary sublimation residue (FSR) particles from erosion of the layered deposits. The color and albedo of the erg and of the layered deposits, and the presence of magnetic material on Mars, suggest that the dark material is composed of low-density aggregates of magnetic dust grains, perhaps similar to FSR particles created in laboratory experiments.

  14. North Polar Erg

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    This VIS image was taken at 82 degrees North latitude during Northern spring. As with yesterday's image, the dunes are still partially frost covered. This region is part of the north polar erg (sand sea), note the complexity and regional coverage of the dunes.

    Image information: VIS instrument. Latitude 81.2, Longitude 118.2 East (241.8 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Characterization of the rod photoresponse isolated from the dark-adapted primate ERG.

    PubMed

    Jamison, J A; Bush, R A; Lei, B; Sieving, P A

    2001-01-01

    The a-wave of the human dark-adapted ERG is thought to derive from activity of rod photoreceptors. However, other sources within the retina could potentially perturb this simple equation. We investigated the extent to which the short-latency dark-adapted rod a-wave of the primate ERG is dominated by the rod photoresponse and the applicability of the phototransduction model to fit the rod a-wave. Dark-adapted Ganzfeld ERGs were elicited over a 5-log-unit intensity range using short bright xenon flashes, and the light-adapted cone responses were subtracted to isolate the rod ERG a-wave. Intravitreal 4-phosphono-butyric acid (APB) and cis-2,3-piperidine-dicarboxylic acid (PDA) were applied to isolate the photoreceptor response. The Hood and Birch version of the phototransduction model, Rmax[1 - e(-I x S x (t-t(eff)))2], was fitted to the a-wave data while allowing Rmax and S to vary. Three principle observations were made: (1) At flash intensities > or =0.77 log sc-td-s the leading edge of the normalized rod ERG a-wave tracks the isolated photoreceptor response across the first 20 ms or up to the point of b-wave intrusion. The rod ERG a-wave was essentially identical to the isolated receptor response for all intensities that produce peak responses within 14 ms after the flash. (2) The best fit of sensitivity (S) was not affected by APB and/or PDA, suggesting that the inner retina contributes very little to the dark-adapted a-wave. (3) APB always reduced the maximum dark-adapted a-wave amplitude (by 15-30%), and PDA always increased it (by 7-15%). Using the phototransduction model, both events can be interpreted as a scaling of the photoreceptor dark current. This suggests that activity of postreceptor cells somehow influences the rod dark current, possibly by feedback through horizontal cells (although currently not demonstrated for the rod system), or by altering the ionic concentrations near the photoreceptors, or by neuromodulator effects mediated by dopamine or

  16. Early Lineage Priming by Trisomy of Erg Leads to Myeloproliferation in a Down Syndrome Model

    PubMed Central

    Ng, Ashley P.; Hu, Yifang; Metcalf, Donald; Hyland, Craig D.; Ierino, Helen; Phipson, Belinda; Wu, Di; Baldwin, Tracey M.; Kauppi, Maria; Kiu, Hiu; Di Rago, Ladina; Hilton, Douglas J.; Smyth, Gordon K.; Alexander, Warren S.

    2015-01-01

    Down syndrome (DS), with trisomy of chromosome 21 (HSA21), is the commonest human aneuploidy. Pre-leukemic myeloproliferative changes in DS foetal livers precede the acquisition of GATA1 mutations, transient myeloproliferative disorder (DS-TMD) and acute megakaryocytic leukemia (DS-AMKL). Trisomy of the Erg gene is required for myeloproliferation in the Ts(1716)65Dn DS mouse model. We demonstrate here that genetic changes specifically attributable to trisomy of Erg lead to lineage priming of primitive and early multipotential progenitor cells in Ts(1716)65Dn mice, excess megakaryocyte-erythroid progenitors, and malignant myeloproliferation. Gene expression changes dependent on trisomy of Erg in Ts(1716)65Dn multilineage progenitor cells were correlated with those associated with trisomy of HSA21 in human DS hematopoietic stem and primitive progenitor cells. These data suggest a role for ERG as a regulator of hematopoietic lineage potential, and that trisomy of ERG in the context of DS foetal liver hemopoiesis drives the pre-leukemic changes that predispose to subsequent DS-TMD and DS-AMKL. PMID:25973911

  17. TMPRSS2:ERG Gene Fusions in Prostate Cancer of West African Men and a Meta-Analysis of Racial Differences

    PubMed Central

    Zhou, Cindy Ke; Young, Denise; Yeboah, Edward D; Coburn, Sally B; Tettey, Yao; Biritwum, Richard B; Adjei, Andrew A; Tay, Evelyn; Niwa, Shelley; Truelove, Ann; Welsh, Judith; Mensah, James E; Hoover, Robert N; Sesterhenn, Isabell A; Hsing, Ann W; Srivastava, Shiv; Cook, Michael B

    2017-01-01

    Abstract The prevalence of fusions of the transmembrane protease, serine 2, gene (TMPRSS2) with the erythroblast transformation-specific–related gene (ERG), or TMPRSS2:ERG, in prostate cancer varies by race. However, such somatic aberration and its association with prognostic factors have neither been studied in a West African population nor been systematically reviewed in the context of racial differences. We used immunohistochemistry to assess oncoprotein encoded by the ERG gene as the established surrogate of ERG fusion genes among 262 prostate cancer biopsies from the Ghana Prostate Study (2004–2006). Poisson regression with robust variance estimation provided prevalence ratios and 95% confidence intervals of ERG expression in relation to patient characteristics. We found that 47 of 262 (18%) prostate cancers were ERG-positive, and being negative for ERG staining was associated with higher Gleason score. We further conducted a systematic review and meta-analysis of TMPRSS2:ERG fusions in relation to race, Gleason score, and tumor stage, combining results from Ghana with 40 additional studies. Meta-analysis showed the prevalence of TMPRSS2:ERG fusions in prostate cancer to be highest in men of European descent (49%), followed by men of Asian (27%) and then African (25%) descent. The lower prevalence of TMPRSS2:ERG fusions in men of African descent implies that alternative genomic mechanisms might explain the disproportionately high prostate cancer burden in such populations. PMID:28633309

  18. Colorimetric TMPRSS2-ERG Gene Fusion Detection in Prostate Cancer Urinary Samples via Recombinase Polymerase Amplification.

    PubMed

    Koo, Kevin M; Wee, Eugene J H; Trau, Matt

    2016-01-01

    TMPRSS2 (Exon 1)-ERG (Exon 4) is the most frequent gene fusion event in prostate cancer (PC), and is highly PC-specific unlike the current serum prostate specific antigen (PSA) biomarker. However, TMPRSS2-ERG levels are currently measured with quantitative reverse-transcription PCR (RT-qPCR) which is time-consuming and requires costly equipment, thus limiting its use in clinical diagnostics. Herein, we report a novel rapid, cost-efficient and minimal-equipment assay named "FusBLU" for detecting TMPRSS2-ERG gene fusions from urine. TMPRSS2-ERG mRNA was amplified by isothermal reverse transcription-recombinase polymerase amplification (RT-RPA), magnetically-isolated, and detected through horseradish peroxidase (HRP)-catalyzed colorimetric reaction. FusBLU was specific for TMPRSS2-ERG mRNA with a low visual detection limit of 10(5) copies. We also demonstrated assay readout versatility on 3 potentially useful platforms. The colorimetric readout was detectable by naked eye for a quick yes/no evaluation of gene fusion presence. On the other hand, a more quantitative TMPRSS2-ERG detection was achievable by absorbance/electrochemical measurements. FusBLU was successfully applied to 12 urinary samples and results were validated by gold-standard RT-qPCR. We also showed that sediment RNA was likely the main source of TMPRSS2-ERG mRNA in urinary samples. We believe that our assay is a potential clinical screening tool for PC and could also have wide applications for other disease-related fusion genes.

  19. Electron {sup 83}Rb/{sup 83m}Kr Source for the Energy Scale Monitoring in the KATRIN Experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zboril, Miroslav; Nuclear Physics Institute of the ASCR, p. r. i., CZ-25068 Rez; Collaboration: KATRIN Collaboration

    The KATRIN (KArlsruhe TRItium Neutrino) experiment investigates the endpoint region of the tritium {beta}-spectrum aiming for the sensitivity on the neutrino mass of 0.2 eV (90% C.L.). A spectrometer of the MAC-E filter (Magnetic Adiabatic Collimation with an Electrostatic filter) type will be used for a total time of at least 5 years. An unrecognized shift of the filtering potential would directly influence the resulting neutrino mass. To continuously monitor the filtering potential the high voltage (HV) will be simultaneously applied to an additional MAC-E filter spectrometer. In this monitor spectrometer suitable electron sources based on atomic/nuclear standards will bemore » utilized. As one of such monitoring tools the solid {sup 83}Rb/{sup 83m}Kr source is intended. It provides conversion electrons from {sup 83m}Kr(t{sub 1/2} = 1.83 h) which is continuously generated by {sup 83}Rb(t{sub 1/2}{approx_equal}86 d). The Calibration and Monitoring task of the KATRIN project demands the long-term energy stability {Delta}E/E of the K-32 conversion electron line (E = 17.8 keV, {Gamma} = 2.7 eV) of {+-}1.6 ppm/month.« less

  20. Pleiotropic biological activities of alternatively spliced TMPRSS2/ERG fusion gene transcripts

    PubMed Central

    Wang, Jianghua; Cai, Yi; Yu, Wendong; Ren, Chengxi; Spencer, David M.; Ittmann, Michael

    2008-01-01

    TMPRSS2/ERG gene fusions are found in the majority of prostate cancers; however, there is significant heterogeneity in the 5′ region of the alternatively spliced fusion gene transcripts. We have found that there is also significant heterogeneity within the coding exons as well. There is variable inclusion of a 72-bp exon and other novel alternatively spliced isoforms. To assess the biological significance of these alternatively spliced transcripts, we expressed various transcripts in primary prostatic epithelial cells and in an immortalized prostatic epithelial cell line, PNT1a. The fusion gene transcripts promoted proliferation, invasion and motility with variable activities that depended on the structure of the 5′ region encoding the TMPRSS2/ERG fusion and the presence of the 72-bp exon. Cotransfection of different isoforms further enhanced biological activity, mimicking the situation in vivo, in which multiple isoforms are expressed. Finally, knockdown of the fusion gene in VCaP cells resulted in inhibition of proliferation in vitro and tumor progression in an in vivo orthotopic mice model. Our results indicate that TMPRSS2/ERG fusion isoforms have variable biological activities promoting tumor initiation and progression and are consistent with our previous clinical observations indicating that certain TMPRSS2/ERG fusion isoforms are significantly correlated with more aggressive disease. PMID:18922926

  1. Effect of Voriconazole on Candida tropicalis Biofilms: Relation with ERG Genes Expression.

    PubMed

    Fernandes, Tânia; Silva, Sónia; Henriques, Mariana

    2016-10-01

    Candida tropicalis has emerged as the third most prevalent fungal pathogens and its ability to form biofilms has been considered one of the most important virulence factors, since biofilms represent high tolerance to antifungal agents. However, the mechanisms of C. tropicalis biofilm resistance to antifungals remain poorly understood. Thus, the main aim of this work was to infer about the effect of voriconazole on the formation and control of C. tropicalis biofilms and disclose its relationship with ERG genes' expression. Planktonic cells tolerance of several C. tropicalis clinical isolates to voriconazole was determined through of antifungal susceptibility test, and the effect of this azole against C. tropicalis biofilm formation and pre-formed biofilms was evaluated by cultivable cells determination and total biomass quantification. ERG genes expression was analyzed by quantitative real-time polymerase chain reaction. This work showed that C. tropicalis resistance to voriconazole is strain dependent and that voriconazole was able to partially control biofilm formation, but was unable to eradicate C. tropicalis pre-formed biofilms. Moreover, C. tropicalis biofilms resistance to voriconazole seems to be associated with alterations of sterol content in the cell membrane, resulting in ERG genes overexpression. Voriconazole is unable to control C. tropicalis biofilms, and the overexpression of ERG genes is a possible mechanism of biofilm resistance.

  2. F463L increases the potential of dofetilide on human ether-a-go-go-related gene (hERG) channels.

    PubMed

    Cheng, Gong; Wu, Jine; Han, Wenqi; Sun, Chaofeng

    2018-06-01

    Mutations in genes related to long QT syndrome (LQTS) is recognized as an independent risk of drug-induced LQTS. We previously screened a mutation F463L in a Chinese patient with LQT2, syncope, and epilepsy. Here, we planned to illustrate how F463L influences the action of dofetilide on hERG channels. F463L-hERG plasmids were transfected into the stable Human Embryonic Kidney 293 (HEK293) cells expressing WT-hERG to generate heterozygous mutant (WT + F463L-hERG). Whole-cell patch clamp and laser confocal scanning microscopy were used to evaluate electrophysiological consequences and the membrane distribution of hERG protein. In comparison of WT-hERG channels exposed to dofetilide, heterozygous F463L-hERG channels showed a reduction in the density of tail currents when exposed amidarone. F463L-hERG also altered the action of dofetilide on the gating properties of hERG channels. Images of dofetilide-treated cells expressing heterozygous F463L showed a severe retention and reduction of protein expression on the membrane compared to WT. In conclusion, dofetilide displays a powerful inhibitory effect on the currents from cells expressing heterozygous F463L, thus showing an additive suppression of currents by F463L with dofetilide. © 2018 Wiley Periodicals, Inc.

  3. MAPK/ERK2 phosphorylates ERG at serine 283 in leukemic cells and promotes stem cell signatures and cell proliferation

    PubMed Central

    Huang, Y; Thoms, JAI; Tursky, ML; Knezevic, K; Beck, D; Chandrakanthan, V; Suryani, S; Olivier, J; Boulton, A; Glaros, EN; Thomas, SR; Lock, RB; MacKenzie, KL; Bushweller, JH; Wong, JWH; Pimanda, JE

    2018-01-01

    Aberrant ERG (v-ets avian erythroblastosis virus E26 oncogene homolog) expression drives leukemic transformation in mice and high expression is associated with poor patient outcomes in acute myeloid leukemia (AML) and T-acute lymphoblastic leukemia (T-ALL). Protein phosphorylation regulates the activity of many ETS factors but little is known about ERG in leukemic cells. To characterize ERG phosphorylation in leukemic cells, we applied liquid chromatography coupled tandem mass spectrometry and identified five phosphorylated serines on endogenous ERG in T-ALL and AML cells. S283 was distinct as it was abundantly phosphorylated in leukemic cells but not in healthy hematopoietic stem and progenitor cells (HSPCs). Overexpression of a phosphoactive mutant (S283D) increased expansion and clonogenicity of primary HSPCs over and above wild-type ERG. Using a custom antibody, we screened a panel of primary leukemic xenografts and showed that ERG S283 phosphorylation was mediated by mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling and in turn regulated expression of components of this pathway. S283 phosphorylation facilitates ERG enrichment and transactivation at the ERG +85 HSPC enhancer that is active in AML and T-ALL with poor prognosis. Taken together, we have identified a specific post-translational modification in leukemic cells that promotes progenitor proliferation and is a potential target to modulate ERG-driven transcriptional programs in leukemia. PMID:27055868

  4. Localization and functional consequences of a direct interaction between TRIOBP-1 and hERG proteins in the heart.

    PubMed

    Jones, David K; Johnson, Ashley C; Roti Roti, Elon C; Liu, Fang; Uelmen, Rebecca; Ayers, Rebecca A; Baczko, Istvan; Tester, David J; Ackerman, Michael J; Trudeau, Matthew C; Robertson, Gail A

    2018-03-22

    Reduced levels of the cardiac human (h)ERG ion channel protein and the corresponding repolarizing current I Kr can cause arrhythmia and sudden cardiac death, but the underlying cellular mechanisms controlling hERG surface expression are not well understood. Here, we identified TRIOBP-1, an F-actin-binding protein previously associated with actin polymerization, as a putative hERG-interacting protein in a yeast-two hybrid screen of a cardiac library. We corroborated this interaction by performing Förster resonance energy transfer (FRET) in HEK293 cells and co-immunoprecipitation in HEK293 cells and native cardiac tissue. TRIOBP-1 overexpression reduced hERG surface expression and current density, whereas reducing TRIOBP-1 expression via shRNA knockdown resulted in increased hERG protein levels. Immunolabeling in rat cardiomyocytes showed that native TRIOBP-1 colocalized predominantly with myosin-binding protein C and secondarily with rat ERG. In human stem cell-derived cardiomyocytes, TRIOBP-1 overexpression caused intracellular co-sequestration of hERG signal, reduced native I Kr and disrupted action potential repolarization. Ca 2+ currents were also somewhat reduced and cell capacitance was increased. These findings establish that TRIOBP-1 interacts directly with hERG and can affect protein levels, I Kr magnitude and cardiac membrane excitability. © 2018. Published by The Company of Biologists Ltd.

  5. A DNA methylation microarray-based study identifies ERG as a gene commonly methylated in prostate cancer.

    PubMed

    Schwartzman, Jacob; Mongoue-Tchokote, Solange; Gibbs, Angela; Gao, Lina; Corless, Christopher L; Jin, Jennifer; Zarour, Luai; Higano, Celestia; True, Lawrence D; Vessella, Robert L; Wilmot, Beth; Bottomly, Daniel; McWeeney, Shannon K; Bova, G Steven; Partin, Alan W; Mori, Motomi; Alumkal, Joshi

    2011-10-01

    DNA methylation of promoter regions is a common event in prostate cancer, one of the most common cancers in men worldwide. Because prior reports demonstrating that DNA methylation is important in prostate cancer studied a limited number of genes, we systematically quantified the DNA methylation status of 1505 CpG dinucleotides for 807 genes in 78 paraffin-embedded prostate cancer samples and three normal prostate samples. The ERG gene, commonly repressed in prostate cells in the absence of an oncogenic fusion to the TMPRSS2 gene, was one of the most commonly methylated genes, occurring in 74% of prostate cancer specimens. In an independent group of patient samples, we confirmed that ERG DNA methylation was common, occurring in 57% of specimens, and cancer-specific. The ERG promoter is marked by repressive chromatin marks mediated by polycomb proteins in both normal prostate cells and prostate cancer cells, which may explain ERG's predisposition to DNA methylation and the fact that tumors with ERG DNA methylation were more methylated, in general. These results demonstrate that bead arrays offer a high-throughput method to discover novel genes with promoter DNA methylation such as ERG, whose measurement may improve our ability to more accurately detect prostate cancer.

  6. Geospace exploration project: Arase (ERG)

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Kasaba, Y.; Shinohara, I.; Takashima, T.; Asamura, K.; Matsumoto, H.; Higashio, N.; Mitani, T.; Kasahara, S.; Yokota, S.; Wang, S.; Kazama, Y.; Kasahara, Y.; Yagitani, S.; Matsuoka, A.; Kojima, H.; Katoh, Y.; Shiokawa, K.; Seki, K.; Fujimoto, M.; Ono, T.; ERG project Group

    2017-06-01

    The ERG (Exploration of energization and Radiation in Geospace) is Japanese geospace exploration project. The project focuses on relativistic electron acceleration mechanism of the outer belt and dynamics of space storms in the context of the cross-energy coupling via wave-particle interactions. The project consists of the satellite observation team, the ground-based network observation team, and integrated-data analysis/simulation team. The satellite was launched on December 20 2016 and has been nicknamed, “Arase”. This paper describes overview of the project and future plan for observations.

  7. Concurrent nuclear ERG and MYC protein overexpression defines a subset of locally advanced prostate cancer: Potential opportunities for synergistic targeted therapeutics.

    PubMed

    Udager, Aaron M; DeMarzo, Angelo M; Shi, Yang; Hicks, Jessica L; Cao, Xuhong; Siddiqui, Javed; Jiang, Hui; Chinnaiyan, Arul M; Mehra, Rohit

    2016-06-01

    Recurrent ERG gene fusions, the most common genetic alterations in prostate cancer, drive overexpression of the nuclear transcription factor ERG, and are early clonal events in prostate cancer progression. The nuclear transcription factor MYC is also frequently overexpressed in prostate cancer and may play a role in tumor initiation and/or progression. The relationship between nuclear ERG and MYC protein overexpression in prostate cancer, as well as the clinicopathologic characteristics and prognosis of ERG-positive/MYC high tumors, is not well understood. Immunohistochemistry (IHC) for ERG and MYC was performed on formalin-fixed, paraffin-embedded tissue from prostate cancer tissue microarrays (TMAs), and nuclear staining was scored semi-quantitatively (IHC product score range = 0-300). Correlation between nuclear ERG and MYC protein expression and association with clinicopathologic parameters and biochemical recurrence after radical prostatectomy was assessed. 29.1% of all tumor nodules showed concurrent nuclear ERG and MYC protein overexpression (i.e., ERG-positive/MYC high), including 35.0% of secondary nodules. Overall, there was weak positive correlation between ERG and MYC expression across all tumor nodules (rpb  = 0.149, P = 0.045), although this correlation was strongest in secondary nodules (rpb  = 0.520, P = 0.019). In radical prostatectomy specimens, ERG-positive/MYC high tumors were positively associated with the presence of extraprostatic extension (EPE), relative to all other ERG/MYC expression subgroups, however, there was no significant association between concurrent nuclear ERG and MYC protein overexpression and time to biochemical recurrence. Concurrent nuclear ERG and MYC protein overexpression is common in prostate cancer and defines a subset of locally advanced tumors. Recent data indicates that BET bromodomain proteins regulate ERG gene fusion and MYC gene expression in prostate cancer, suggesting possible synergistic

  8. Overcoming hERG affinity in the discovery of maraviroc; a CCR5 antagonist for the treatment of HIV.

    PubMed

    Price, David A; Armour, Duncan; de Groot, Marcel; Leishman, Derek; Napier, Carolyn; Perros, Manos; Stammen, Blanda L; Wood, Anthony

    2008-01-01

    Avoiding cardiac liability associated with blockade of hERG (human ether a go-go) is key for successful drug discovery and development. This paper describes the work undertaken in the discovery of a potent CCR5 antagonist, maraviroc 34, for the treatment of HIV. In particular the use of a pharmacophore model of the hERG channel and a high throughput binding assay for the hERG channel are described that were critical to elucidate SAR to overcome hERG liabilities. The key SAR involves the introduction of polar substituents into regions of the molecule where it is postulated to undergo hydrophobic interactions with the ion channel. Within the CCR5 project there appeared to be no strong correlation between hERG affinity and physiochemical parameters such as pKa or lipophilicity. It is believed that chemists could apply these same strategies early in drug discovery to remove hERG interactions associated with lead compounds while retaining potency at the primary target.

  9. TMPRSS2-ERG gene fusions are infrequent in prostatic ductal adenocarcinomas.

    PubMed

    Lotan, Tamara L; Toubaji, Antoun; Albadine, Roula; Latour, Mathieu; Herawi, Mehsati; Meeker, Alan K; DeMarzo, Angelo M; Platz, Elizabeth A; Epstein, Jonathan I; Netto, George J

    2009-03-01

    Ductal adenocarcinoma of the prostate is an unusual subtype that may be associated with a more aggressive clinical course, and is less responsive to conventional therapies than the more common prostatic acinar adenocarcinoma. However, given its frequent association with an acinar component at prostatectomy, some have challenged the concept of prostatic ductal adenocarcinoma as a distinct clinicopathologic entity. We studied the occurrence of the TMPRSS2-ERG gene fusion, in 40 surgically resected ductal adenocarcinoma cases, and in their associated acinar component using fluorescence in situ hybridization. A group of 38 'pure' acinar adenocarcinoma cases matched with the ductal adenocarcinoma group for pathological grade and stage was studied as a control. Compared with the matched acinar adenocarcinoma cases, the TMPRSS2-ERG gene fusion was significantly less frequently observed in ductal adenocarcinoma (45 vs 11% of cases, P=0.002, Fisher's exact test). Here, of the ductal adenocarcinoma cases with the gene fusion, 75% were fused through deletion, and the remaining case was fused through translocation. The TMPRSS2-ERG gene fusion was also rare in the acinar component of mixed ductal-acinar tumors when compared with the pure acinar adenocarcinoma controls (5 vs 45%, P=0.001, Fisher's exact test). In 95% of the ductal adenocarcinoma cases in which a concurrent acinar component was analyzed, there was concordance for presence/absence of the TMPRSS2-ERG gene fusion between the different histologic subtypes. In the control group of pure acinar adenocarcinoma cases, 59% were fused through deletion and 41% were fused through translocation. The presence of the TMPRSS2-ERG gene fusion in some cases of prostatic ductal adenocarcinoma supports the concept that ductal adenocarcinoma and acinar adenocarcinoma may be related genetically. However, the significantly lower rate of the gene fusion in pure ductal adenocarcinoma cases underscores the fact that genetic and biologic

  10. Role of the pH in state-dependent blockade of hERG currents

    NASA Astrophysics Data System (ADS)

    Wang, Yibo; Guo, Jiqing; Perissinotti, Laura L.; Lees-Miller, James; Teng, Guoqi; Durdagi, Serdar; Duff, Henry J.; Noskov, Sergei Yu.

    2016-10-01

    Mutations that reduce inactivation of the voltage-gated Kv11.1 potassium channel (hERG) reduce binding for a number of blockers. State specific block of the inactivated state of hERG block may increase risks of drug-induced Torsade de pointes. In this study, molecular simulations of dofetilide binding to the previously developed and experimentally validated models of the hERG channel in open and open-inactivated states were combined with voltage-clamp experiments to unravel the mechanism(s) of state-dependent blockade. The computations of the free energy profiles associated with the drug block to its binding pocket in the intra-cavitary site display startling differences in the open and open-inactivated states of the channel. It was also found that drug ionization may play a crucial role in preferential targeting to the open-inactivated state of the pore domain. pH-dependent hERG blockade by dofetilie was studied with patch-clamp recordings. The results show that low pH increases the extent and speed of drug-induced block. Both experimental and computational findings indicate that binding to the open-inactivated state is of key importance to our understanding of the dofetilide’s mode of action.

  11. ERG/AKR1C3/AR Constitutes a Feed-Forward Loop for AR Signaling in Prostate Cancer Cells.

    PubMed

    Powell, Katelyn; Semaan, Louie; Conley-LaComb, M Katie; Asangani, Irfan; Wu, Yi-Mi; Ginsburg, Kevin B; Williams, Julia; Squire, Jeremy A; Maddipati, Krishna R; Cher, Michael L; Chinni, Sreenivasa R

    2015-06-01

    Intratumoral androgen synthesis in prostate cancer contributes to the development of castration-resistant prostate cancer (CRPC). Several enzymes responsible for androgen biosynthesis have been shown to be overexpressed in CRPC, thus contributing to CRPC in a castrated environment. The TMPRSS2-ERG transcription factor has been shown to be present in primary prostate cancer tumors as well as CRPC tumors. We hypothesize that TMPRSS2-ERG fusions regulate androgen biosynthetic enzyme (ABE) gene expression and the production of androgens, which contributes to the development of CRPC. We used a panel of assays, including lentivirus transduction, gene expression, chromatin immunoprecipitation and sequencing, liquid chromatography-mass spectrometric quantitation, immunocytochemistry, immunohistochemistry, and bioinformatics analysis of gene microarray databases, to determine ERG regulation of androgen synthesis. We found that ERG regulated the expression of the ABE AKR1C3 in prostate cancer cells via direct binding to the AKR1C3 gene. Knockdown of ERG resulted in reduced AKR1C3 expression, which caused a reduction in both DHT synthesis and PSA expression in VCaP prostate cancer cells treated with 5α-androstanedione (5α-Adione), a DHT precursor metabolite. Immunohistochemical staining revealed that ERG was coexpressed with AKR1C3 in prostate cancer tissue samples. These data suggest that AKR1C3 catalyzes the biochemical reduction of 5α-Adione to DHT in prostate cancer cells, and that ERG regulates this step through upregulation of AKR1C3 expression. Elucidation of ERG regulation of ABEs in CRPC may help to stratify TMPRSS2-ERG fusion-positive prostate cancer patients in the clinic for anti-androgen receptor-driven therapies; and AKR1C3 may serve as a valuable therapeutic target in the treatment of CRPC. ©2015 American Association for Cancer Research.

  12. Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer

    DTIC Science & Technology

    2017-10-01

    SUPPLEMENTARY NOTES 14. ABSTRACT Prostate cancer (PCA) is a clinically and genetically heterogeneous and the development of a molecular classification is...AWARD NUMBER: W81XWH-16-1-0739 TITLE: Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer PRINCIPAL...AND SUBTITLE 5a. CONTRACT NUMBER Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer 5b. GRANT NUMBER W81XWH

  13. ADMET Evaluation in Drug Discovery. 16. Predicting hERG Blockers by Combining Multiple Pharmacophores and Machine Learning Approaches.

    PubMed

    Wang, Shuangquan; Sun, Huiyong; Liu, Hui; Li, Dan; Li, Youyong; Hou, Tingjun

    2016-08-01

    Blockade of human ether-à-go-go related gene (hERG) channel by compounds may lead to drug-induced QT prolongation, arrhythmia, and Torsades de Pointes (TdP), and therefore reliable prediction of hERG liability in the early stages of drug design is quite important to reduce the risk of cardiotoxicity-related attritions in the later development stages. In this study, pharmacophore modeling and machine learning approaches were combined to construct classification models to distinguish hERG active from inactive compounds based on a diverse data set. First, an optimal ensemble of pharmacophore hypotheses that had good capability to differentiate hERG active from inactive compounds was identified by the recursive partitioning (RP) approach. Then, the naive Bayesian classification (NBC) and support vector machine (SVM) approaches were employed to construct classification models by integrating multiple important pharmacophore hypotheses. The integrated classification models showed improved predictive capability over any single pharmacophore hypothesis, suggesting that the broad binding polyspecificity of hERG can only be well characterized by multiple pharmacophores. The best SVM model achieved the prediction accuracies of 84.7% for the training set and 82.1% for the external test set. Notably, the accuracies for the hERG blockers and nonblockers in the test set reached 83.6% and 78.2%, respectively. Analysis of significant pharmacophores helps to understand the multimechanisms of action of hERG blockers. We believe that the combination of pharmacophore modeling and SVM is a powerful strategy to develop reliable theoretical models for the prediction of potential hERG liability.

  14. Effect of shorter dark adaptation on ISCEV standard DA 0.01 and DA 3 skin ERGs in healthy adults.

    PubMed

    Hamilton, R; Graham, K

    2016-08-01

    To quantify dark-adapted (DA) skin ERG changes during 20 min of dark adaptation. Sixteen healthy adult subjects were dark-adapted for 20 min during which ISCEV standard dim (0.01 phot cd s m(-2)) white flash ERGs were recorded at 1, 2, 3, 4, 5, 10, 15 and 20 min, and bright (3 phot cd s m(-2)) white ERGs were recorded at 2, 5, 10, 15 and 20 min without mydriasis and using skin electrodes. Amplitudes and peak times were normalised to 20 min values. Halving dark adaptation from 20 to 10 min had no measureable effect on the DA 3 ERG and caused a 10 % amplitude loss (range 0-23 %) only for the DA 0.01 ERG b-wave amplitude. No significant peak time changes resulted, nor increased parameter variability. Reducing dark adaptation from 20 to 10 min or even less has an effect on only DA 0.01 ERGs. Shorter dark adaptation than 20 min may not compromise the clinical utility of the ERG providing clinics adhere to the usual standards of adequate reference data.

  15. Use of molecular modeling aided design to dial out hERG liability in adenosine A(2A) receptor antagonists.

    PubMed

    Deng, Qiaolin; Lim, Yeon-Hee; Anand, Rajan; Yu, Younong; Kim, Jae-hun; Zhou, Wei; Zheng, Junying; Tempest, Paul; Levorse, Dorothy; Zhang, Xiaoping; Greene, Scott; Mullins, Deborra; Culberson, Chris; Sherborne, Brad; Parker, Eric M; Stamford, Andrew; Ali, Amjad

    2015-08-01

    Molecular modeling was performed on a triazolo quinazoline lead compound to help develop a series of adenosine A2A receptor antagonists with improved hERG profile. Superposition of the lead compound onto MK-499, a benchmark hERG inhibitor, combined with pKa calculations and measurement, identified terminal fluorobenzene to be responsible for hERG activity. Docking of the lead compound into an A2A crystal structure suggested that this group is located at a flexible, spacious, and solvent-exposed opening of the binding pocket, making it possible to tolerate various functional groups. Transformation analysis (MMP, matched molecular pair) of in-house available experimental data on hERG provided suggestions for modifications in order to mitigate this liability. This led to the synthesis of a series of compounds with significantly reduced hERG activity. The strategy used in the modeling work can be applied to other medicinal chemistry programs to help improve hERG profile. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Postsynaptic ERG potassium channels limit muscle excitability to allow distinct egg-laying behavior states in C. elegans

    PubMed Central

    Collins, Kevin M.; Koelle, Michael R.

    2013-01-01

    C. elegans regulates egg laying by alternating between an inactive phase and a serotonin-triggered active phase. We found that the conserved ERG potassium channel UNC-103 enables this two-state behavior by limiting excitability of the egg-laying muscles. Using both high-speed video recording and calcium imaging of egg-laying muscles in behaving animals, we found that the muscles appear to be excited at a particular phase of each locomotor body bend. During the inactive phase, this rhythmic excitation infrequently evokes calcium transients or contraction of the egg-laying muscles. During the serotonin-triggered active phase, however, these muscles are more excitable and each body bend is accompanied by a calcium transient that drives twitching or full contraction of the egg-laying muscles. We found that ERG null mutants lay eggs too frequently, and that ERG function is necessary and sufficient in the egg-laying muscles to limit egg laying. ERG K+ channels localize to postsynaptic sites in the egg-laying muscle, and mutants lacking ERG have more frequent calcium transients and contractions of the egg-laying muscles even during the inactive phase. Thus ERG channels set postsynaptic excitability at a threshold so that further adjustments of excitability by serotonin generate two distinct behavioral states. PMID:23303953

  17. Hypermethylated ERG as a cell-free fetal DNA biomarker for non-invasive prenatal testing of Down syndrome.

    PubMed

    Chen, Xi; Xiong, Likuan; Zeng, Ting; Xiao, Kelin; Huang, Yanping; Guo, Hui; Ren, Jinghui

    2015-04-15

    Previous reports have shown that the ERG gene is hypermethylated in the placenta and hypomethylated in maternal blood cells. In this study, we explore the feasibility of hypermethylated ERG as a cell-free fetal (cff) DNA biomarker for non-invasive prenatal testing (NIPT) of Down syndrome. We randomly selected 90 healthy pregnant women, including 30 cases at each trimester of pregnancy. In addition, 15 pregnant women were recruited as the case group whose fetuses had been confirmed to have trisomy 21 by amniotic fluid analysis at 18th to 26th week gestation. Using HpaII, MspІ to digest cell-free maternal plasma DNA, we performed SYBR Green PCR to detect methylated sites of ERG sequences, and analyzed the concentrations of cff DNA in maternal plasma in different gestational trimesters and the case group. The ERG median concentrations of the maternal plasma after Hpa II digestion (LG copies/ml) in first, second and third-trimesters were 5.38, 6.10, and 7.04, respectively (Kruskal-Wallis, P<0.01); and that in the trisomy 21 case group was 6.85, which was higher than the second-trimester (Mann-Whitney, P<0.01). The study demonstrated that ERG gene is hypermethylated in cff DNA but hypomethylated in maternal DNA; and the median concentration of ERG gene in the trisomy 21 case group is higher than that in the gestational trimester matched normal group. ERG gene, as a fetal DNA biomarker, may be useful for NIPT of Down syndrome. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. PCA3 Reference Set Application: T2-Erg-Martin Sanda-Emory (2014) — EDRN Public Portal

    Cancer.gov

    We hypothesize that combining T2:erg (T2:erg) fusion and PCA3 detection in urine collected after digital rectal exam can improve the specificity of identifying clinically significant prostate cancer presence over the standard PSA and DRE. To address this hypothesis we propose to validate the performance of the urinary T2:erg in a multiplex model predicting the diagnosis of clinically significant prostate cancer on subsequent prostate biopsy using post-DRE pre biopsy urine specimens from a cohort of 900 men on the EDRN’s PCA3 trial.

  19. Effects of Tannic Acid, Green Tea and Red Wine on hERG Channels Expressed in HEK293 Cells.

    PubMed

    Chu, Xi; Guo, Yusong; Xu, Bingyuan; Li, Wenya; Lin, Yue; Sun, Xiaorun; Ding, Chunhua; Zhang, Xuan

    2015-01-01

    Tannic acid presents in varying concentrations in plant foods, and in relatively high concentrations in green teas and red wines. Human ether-à-go-go-related gene (hERG) channels expressed in multiple tissues (e.g. heart, neurons, smooth muscle and cancer cells), and play important roles in modulating cardiac action potential repolarization and tumor cell biology. The present study investigated the effects of tannic acid, green teas and red wines on hERG currents. The effects of tannic acid, teas and red wines on hERG currents stably transfected in HEK293 cells were studied with a perforated patch clamp technique. In this study, we demonstrated that tannic acid inhibited hERG currents with an IC50 of 3.4 μM and ~100% inhibition at higher concentrations, and significantly shifted the voltage dependent activation to more positive potentials (Δ23.2 mV). Remarkably, a 100-fold dilution of multiple types of tea (green tea, oolong tea and black tea) or red wine inhibited hERG currents by ~90%, and significantly shifted the voltage dependent activation to more positive potentials (Δ30.8 mV and Δ26.0 mV, respectively). Green tea Lung Ching and red wine inhibited hERG currents, with IC50 of 0.04% and 0.19%, respectively. The effects of tannic acid, teas and red wine on hERG currents were irreversible. These results suggest tannic acid is a novel hERG channel blocker and consequently provide a new mechanistic evidence for understanding the effects of tannic acid. They also revealed the potential pharmacological basis of tea- and red wine-induced biology activities.

  20. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase.

    PubMed

    Kaneshiro, Edna S; Johnston, Laura Q; Nkinin, Stephenson W; Romero, Becky I; Giner, José-Luis

    2015-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The Pneumocystis carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions, whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild-type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy ((1)H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ(24(28)) -sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

  1. Effects of Tannic Acid, Green Tea and Red Wine on hERG Channels Expressed in HEK293 Cells

    PubMed Central

    Xu, Bingyuan; Li, Wenya; Lin, Yue; Sun, Xiaorun; Ding, Chunhua; Zhang, Xuan

    2015-01-01

    Tannic acid presents in varying concentrations in plant foods, and in relatively high concentrations in green teas and red wines. Human ether-à-go-go-related gene (hERG) channels expressed in multiple tissues (e.g. heart, neurons, smooth muscle and cancer cells), and play important roles in modulating cardiac action potential repolarization and tumor cell biology. The present study investigated the effects of tannic acid, green teas and red wines on hERG currents. The effects of tannic acid, teas and red wines on hERG currents stably transfected in HEK293 cells were studied with a perforated patch clamp technique. In this study, we demonstrated that tannic acid inhibited hERG currents with an IC50 of 3.4 μM and ~100% inhibition at higher concentrations, and significantly shifted the voltage dependent activation to more positive potentials (Δ23.2 mV). Remarkably, a 100-fold dilution of multiple types of tea (green tea, oolong tea and black tea) or red wine inhibited hERG currents by ~90%, and significantly shifted the voltage dependent activation to more positive potentials (Δ30.8 mV and Δ26.0 mV, respectively). Green tea Lung Ching and red wine inhibited hERG currents, with IC50 of 0.04% and 0.19%, respectively. The effects of tannic acid, teas and red wine on hERG currents were irreversible. These results suggest tannic acid is a novel hERG channel blocker and consequently provide a new mechanistic evidence for understanding the effects of tannic acid. They also revealed the potential pharmacological basis of tea- and red wine-induced biology activities. PMID:26625122

  2. Assessing the Contribution of the Oscillatory Potentials to the Genesis of the Photopic ERG with the Discrete Wavelet Transform.

    PubMed

    Gauvin, Mathieu; Dorfman, Allison L; Trang, Nataly; Gauthier, Mercedes; Little, John M; Lina, Jean-Marc; Lachapelle, Pierre

    2016-01-01

    The electroretinogram (ERG) is composed of slow (i.e., a-, b-waves) and fast (i.e., oscillatory potentials: OPs) components. OPs have been shown to be preferably affected in some diseases (such as diabetic retinopathy), while the a- and b-waves remain relatively intact. The purpose of this study was to determine the contribution of OPs to the building of the ERG and to examine whether a signal mostly composed of OPs could also exist. DWT analyses were performed on photopic ERGs (flash intensities: -2.23 to 2.64 log cd·s·m -2 in 21 steps) obtained from normal subjects ( n = 40) and patients ( n = 21) affected with a retinopathy. In controls, the %OP value (i.e., OPs energy/ERG energy) is stimulus- and amplitude-independent (range: 56.6-61.6%; CV = 6.3%). In contrast, the %OPs measured from the ERGs of our patients varied significantly more (range: 35.4%-89.2%; p < 0.05) depending on the pathology, some presenting with ERGs that are almost solely composed of OPs. In conclusion, patients may present with a wide range of %OP values. Findings herein also support the hypothesis that, in certain conditions, the photopic ERG can be mostly composed of high-frequency components.

  3. Structure and Function of the Splice Variants of TMPRSS2-ERG, a Prevalent Genomic Alteration in Prostate Cancer

    DTIC Science & Technology

    2011-09-01

    the ETS family of transcription factors showing diverse expression patterns in human tissues (Turner and Watson, 2008). ERG, similar to other...and adult mouse tissues . Most striking of these observations was highly selective and abundant expression of erg protein in endothelial cells of...mouse tissues . We for the first time clarified that endogenous ERG was not expressed in normal mouse prostate epithelium (Mohamed et al., 2010

  4. The Role of Monoubiquitination in Endocytic Degradation of Human Ether-a-go-go-related Gene (hERG) Channels under Low K+ Conditions*

    PubMed Central

    Sun, Tao; Guo, Jun; Shallow, Heidi; Yang, Tonghua; Xu, Jianmin; Li, Wentao; Hanson, Christian; Wu, James G.; Li, Xian; Massaeli, Hamid; Zhang, Shetuan

    2011-01-01

    A reduction in extracellular K+ concentration ([K+]o) causes cardiac arrhythmias and triggers internalization of the cardiac rapidly activating delayed rectifier potassium channel (IKr) encoded by the human ether-a-go-go-related gene (hERG). We investigated the role of ubiquitin (Ub) in endocytic degradation of hERG channels stably expressed in HEK cells. Under low K+ conditions, UbKO, a lysine-less mutant Ub that only supports monoubiquitination, preferentially interacted and selectively enhanced degradation of the mature hERG channels. Overexpression of Vps24 protein, also known as charged multivesicular body protein 3, significantly accelerated degradation of mature hERG channels, whereas knockdown of Vps24 impeded this process. Moreover, the lysosomal inhibitor bafilomycin A1 inhibited degradation of the internalized mature hERG channels. Thus, monoubiquitination directs mature hERG channels to degrade through the multivesicular body/lysosome pathway. Interestingly, the protease inhibitor lactacystin inhibited the low K+-induced hERG endocytosis and concomitantly led to an accumulation of monoubiquitinated mature hERG channels, suggesting that deubiquitination is also required for the endocytic degradation. Consistently, overexpression of the endosomal deubiquitinating enzyme signal transducing adaptor molecule-binding protein significantly accelerated whereas knockdown of endogenous signal transducing adaptor molecule-binding protein impeded degradation of the mature hERG channels under low K+ conditions. Thus, monoubiquitin dynamically mediates endocytic degradation of mature hERG channels under low K+ conditions. PMID:21177251

  5. A tritium activity monitor for the KATRIN Experiment

    NASA Astrophysics Data System (ADS)

    Schmitt, Udo

    2008-06-01

    The KArlsruhe TRItium Neutrino experiment KATRIN is designed to measure the absolute neutrino mass scale by analyzing the endpoint region of the tritium beta-decay spectrum with a sensitivity of 0.2 eV/c2 (90 % C.L.). A high-luminous windowless gaseous tritium source with an activity of 1.7 · 1011 Bq will produce the decay electrons, their energy spectrum will be analyzed by a combination of two electrostatic retarding spectrometers with magnetic adiabatic collimation (MAC-E-filter). Fluctuations of the source column density and inelastic scattering processes within the source affect the energy distribution of the decay electrons. Hence, a precise and continuous monitoring of the source activity is necessary to correct the data taken by the main detector. A prototype of the beam monitor detector, based on a silicon drift diode, has been developed to measure an expected counting rate in the range of 106/(s · mm2). The detector element shall be moveable across the complete beam in a magnetic field of 0.8 T, resulting in a beam diameter of 20 cm. A precise sensor positioning device has been designed and built to be compatible with the primary beamline vacuum of 10-11 mbar.

  6. Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X).

    PubMed

    Thomas, Dierk; Hammerling, Bettina C; Wimmer, Anna-Britt; Wu, Kezhong; Ficker, Eckhard; Kuryshev, Yuri A; Scherer, Daniel; Kiehn, Johann; Katus, Hugo A; Schoels, Wolfgang; Karle, Christoph A

    2004-12-01

    The human ether-a-go-go-related gene (hERG) encodes the rapid component of the cardiac repolarizing delayed rectifier potassium current, I(Kr). The direct interaction of the commonly used protein kinase C (PKC) inhibitor bisindolylmaleimide I (BIM I) with hERG, KvLQT1/minK, and I(Kr) currents was investigated in this study. hERG and KvLQT1/minK channels were heterologously expressed in Xenopus laevis oocytes, and currents were measured using the two-microelectrode voltage clamp technique. In addition, hERG currents in stably transfected human embryonic kidney (HEK 293) cells, native I(Kr) currents and action potentials in isolated guinea pig ventricular cardiomyocytes were recorded using whole-cell patch clamp electrophysiology. Bisindolylmaleimide I blocked hERG currents in HEK 293 cells and Xenopus oocytes in a concentration-dependent manner with IC(50) values of 1.0 and 13.2 muM, respectively. hERG channels were primarily blocked in the open state in a frequency-independent manner. Analysis of the voltage-dependence of block revealed a reduction of inhibition at positive membrane potentials. BIM I caused a shift of -20.3 mV in the voltage-dependence of inactivation. The point mutations tyrosine 652 alanine (Y652A) and phenylalanine 656 alanine (F656A) attenuated hERG current blockade, indicating that BIM I binds to a common drug receptor within the pore region. KvLQT1/minK currents were not significantly altered by BIM I. Finally, 1 muM BIM I reduced native I(Kr) currents by 69.2% and lead to action potential prolongation. In summary, PKC-independent effects have to be carefully considered when using BIM I as PKC inhibitor in experimental models involving hERG channels and I(Kr) currents.

  7. Comparison of the Earth's high-latitude disturbances with energetic electrons measured by the ERG/Arase satellite

    NASA Astrophysics Data System (ADS)

    Chiang, C. Y.; Chang, T. F.; Tam, S. W. Y.; Syugu, W. J.; Kazama, Y.; Wang, B. J.; Wang, S. Y.; Kasahara, S.; Yokota, S.; Hori, T.; Yoshizumi, M.; Shinohara, I.

    2017-12-01

    The Exploration of energization and Radiation in Geospace (ERG) satellite has been successfully launched from the Uchinoura Space Center in December 2016. The main goal of the ERG project is to elucidate acceleration and loss mechanisms of relativistic electrons in the radiation belts. In addition, the apogee of the ERG satellite's orbit often exceeds the edge of outer radiation belt in radial distance. Thus the data measured from the higher-L region may be associated with the activities observed in the Earth's high-latitude region. We statistically compare the Auroral Electrojet (AE) index with the data measured by the Low-Energy Particle Experiments - Electron Analyzer (LEP-e) and Medium-Energy Particle Experiments - Electron Analyzer (MEP-e) onboard the ERG satellite in the past months. With the selected data for L > 7, we statistically investigate the contributions of the different electron energies observed in various magnetic local time (MLT) sectors to the Earth's high-latitude disturbances.

  8. Integrated analysis of drug-induced gene expression profiles predicts novel hERG inhibitors.

    PubMed

    Babcock, Joseph J; Du, Fang; Xu, Kaiping; Wheelan, Sarah J; Li, Min

    2013-01-01

    Growing evidence suggests that drugs interact with diverse molecular targets mediating both therapeutic and toxic effects. Prediction of these complex interactions from chemical structures alone remains challenging, as compounds with different structures may possess similar toxicity profiles. In contrast, predictions based on systems-level measurements of drug effect may reveal pharmacologic similarities not evident from structure or known therapeutic indications. Here we utilized drug-induced transcriptional responses in the Connectivity Map (CMap) to discover such similarities among diverse antagonists of the human ether-à-go-go related (hERG) potassium channel, a common target of promiscuous inhibition by small molecules. Analysis of transcriptional profiles generated in three independent cell lines revealed clusters enriched for hERG inhibitors annotated using a database of experimental measurements (hERGcentral) and clinical indications. As a validation, we experimentally identified novel hERG inhibitors among the unannotated drugs in these enriched clusters, suggesting transcriptional responses may serve as predictive surrogates of cardiotoxicity complementing existing functional assays.

  9. Integrated Analysis of Drug-Induced Gene Expression Profiles Predicts Novel hERG Inhibitors

    PubMed Central

    Babcock, Joseph J.; Du, Fang; Xu, Kaiping; Wheelan, Sarah J.; Li, Min

    2013-01-01

    Growing evidence suggests that drugs interact with diverse molecular targets mediating both therapeutic and toxic effects. Prediction of these complex interactions from chemical structures alone remains challenging, as compounds with different structures may possess similar toxicity profiles. In contrast, predictions based on systems-level measurements of drug effect may reveal pharmacologic similarities not evident from structure or known therapeutic indications. Here we utilized drug-induced transcriptional responses in the Connectivity Map (CMap) to discover such similarities among diverse antagonists of the human ether-à-go-go related (hERG) potassium channel, a common target of promiscuous inhibition by small molecules. Analysis of transcriptional profiles generated in three independent cell lines revealed clusters enriched for hERG inhibitors annotated using a database of experimental measurements (hERGcentral) and clinical indications. As a validation, we experimentally identified novel hERG inhibitors among the unannotated drugs in these enriched clusters, suggesting transcriptional responses may serve as predictive surrogates of cardiotoxicity complementing existing functional assays. PMID:23936032

  10. Interaction between the cardiac rapidly (IKr) and slowly (IKs) activating delayed rectifier potassium channels revealed by low K+-induced hERG endocytic degradation.

    PubMed

    Guo, Jun; Wang, Tingzhong; Yang, Tonghua; Xu, Jianmin; Li, Wentao; Fridman, Michael D; Fisher, John T; Zhang, Shetuan

    2011-10-07

    Cardiac repolarization is controlled by the rapidly (I(Kr)) and slowly (I(Ks)) activating delayed rectifier potassium channels. The human ether-a-go-go-related gene (hERG) encodes I(Kr), whereas KCNQ1 and KCNE1 together encode I(Ks). Decreases in I(Kr) or I(Ks) cause long QT syndrome (LQTS), a cardiac disorder with a high risk of sudden death. A reduction in extracellular K(+) concentration ([K(+)](o)) induces LQTS and selectively causes endocytic degradation of mature hERG channels from the plasma membrane. In the present study, we investigated whether I(Ks) compensates for the reduced I(Kr) under low K(+) conditions. Our data show that when hERG and KCNQ1 were expressed separately in human embryonic kidney (HEK) cells, exposure to 0 mM K(+) for 6 h completely eliminated the mature hERG channel expression but had no effect on KCNQ1. When hERG and KCNQ1 were co-expressed, KCNQ1 significantly delayed 0 mM K(+)-induced hERG reduction. Also, hERG degradation led to a significant reduction in KCNQ1 in 0 mM K(+) conditions. An interaction between hERG and KCNQ1 was identified in hERG+KCNQ1-expressing HEK cells. Furthermore, KCNQ1 preferentially co-immunoprecipitated with mature hERG channels that are localized in the plasma membrane. Biophysical and pharmacological analyses indicate that although hERG and KCNQ1 closely interact with each other, they form distinct hERG and KCNQ1 channels. These data extend our understanding of delayed rectifier potassium channel trafficking and regulation, as well as the pathology of LQTS.

  11. hERG blocking potential of acids and zwitterions characterized by three thresholds for acidity, size and reactivity.

    PubMed

    Nikolov, Nikolai G; Dybdahl, Marianne; Jónsdóttir, Svava Ó; Wedebye, Eva B

    2014-11-01

    Ionization is a key factor in hERG K(+) channel blocking, and acids and zwitterions are known to be less probable hERG blockers than bases and neutral compounds. However, a considerable number of acidic compounds block hERG, and the physico-chemical attributes which discriminate acidic blockers from acidic non-blockers have not been fully elucidated. We propose a rule for prediction of hERG blocking by acids and zwitterionic ampholytes based on thresholds for only three descriptors related to acidity, size and reactivity. The training set of 153 acids and zwitterionic ampholytes was predicted with a concordance of 91% by a decision tree based on the rule. Two external validations were performed with sets of 35 and 48 observations, respectively, both showing concordances of 91%. In addition, a global QSAR model of hERG blocking was constructed based on a large diverse training set of 1374 chemicals covering all ionization classes, externally validated showing high predictivity and compared to the decision tree. The decision tree was found to be superior for the acids and zwitterionic ampholytes classes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Involvement of Caveolin in Low K+-induced Endocytic Degradation of Cell-surface Human Ether-a-go-go-related Gene (hERG) Channels*

    PubMed Central

    Massaeli, Hamid; Sun, Tao; Li, Xian; Shallow, Heidi; Wu, Jimmy; Xu, Jianmin; Li, Wentao; Hanson, Christian; Guo, Jun; Zhang, Shetuan

    2010-01-01

    Reduction in the rapidly activating delayed rectifier K+ channel current (IKr) due to either mutations in the human ether-a-go-go-related gene (hERG) or drug block causes inherited or drug-induced long QT syndrome. A reduction in extracellular K+ concentration ([K+]o) exacerbates long QT syndrome. Recently, we demonstrated that lowering [K+]o promotes degradation of IKr in rabbit ventricular myocytes and of the hERG channel stably expressed in HEK 293 cells. In this study, we investigated the degradation pathways of hERG channels under low K+ conditions. We demonstrate that under low K+ conditions, mature hERG channels and caveolin-1 (Cav1) displayed a parallel time-dependent reduction. Mature hERG channels coprecipitated with Cav1 in co-immunoprecipitation analysis, and internalized hERG channels colocalized with Cav1 in immunocytochemistry analysis. Overexpression of Cav1 accelerated internalization of mature hERG channels in 0 mm K+o, whereas knockdown of Cav1 impeded this process. In addition, knockdown of dynamin 2 using siRNA transfection significantly impeded hERG internalization and degradation under low K+o conditions. In cultured neonatal rat ventricular myocytes, knockdown of caveolin-3 significantly impeded low K+o-induced reduction of IKr. Our data indicate that a caveolin-dependent endocytic route is involved in low K+o-induced degradation of mature hERG channels. PMID:20605793

  13. Evidence for the hERG Liability of Antihistamines, Antipsychotics, and Anti-Infective Agents: A Systematic Literature Review From the ARITMO Project.

    PubMed

    Hazell, Lorna; Raschi, Emanuel; De Ponti, Fabrizio; Thomas, Simon H L; Salvo, Francesco; Ahlberg Helgee, Ernst; Boyer, Scott; Sturkenboom, Miriam; Shakir, Saad

    2017-05-01

    A systematic review was performed to categorize the hERG (human ether-a-go-go-related gene) liability of antihistamines, antipsychotics, and anti-infectives and to compare it with current clinical risk of torsade de pointes (TdP). Eligible studies were hERG assays reporting half-minimal inhibitory concentrations (IC50). A "hERG safety margin" was calculated from the IC50 divided by the peak human plasma concentration (free C max ). A margin below 30 defined hERG liability. Each drug was assigned an "uncertainty score" based on volume, consistency, precision, and internal and external validity of evidence. The hERG liability was compared to existing knowledge on TdP risk (www.credibledrugs.org). Of 1828 studies, 82 were eligible, allowing calculation of safety margins for 61 drugs. Thirty-one drugs (51%) had evidence of hERG liability including 6 with no previous mention of TdP risk (eg, desloratadine, lopinavir). Conversely, 16 drugs (26%) had no evidence of hERG liability including 6 with known, or at least conditional or possible, TdP risk (eg, chlorpromazine, sulpiride). The main sources of uncertainty were the validity of the experimental conditions used (antihistamines and antipsychotics) and nonuse of reference compounds (anti-infectives). In summary, hERG liability was categorized for 3 widely used drug classes, incorporating a qualitative assessment of the strength of available evidence. Some concordance with TdP risk was observed, although several drugs had hERG liability without evidence of clinical risk and vice versa. This may be due to gaps in clinical evidence, limitations of hERG/C max data, or other patient/drug-specific factors that contribute to real-life TdP risk. © 2016, The American College of Clinical Pharmacology.

  14. Prostate cancer risk regions at 8q24 and 17q24 are differentially associated with somatic TMPRSS2:ERG fusion status

    PubMed Central

    Luedeke, Manuel; Rinckleb, Antje E.; FitzGerald, Liesel M.; Geybels, Milan S.; Schleutker, Johanna; Eeles, Rosalind A.; Teixeira, Manuel R.; Cannon-Albright, Lisa; Ostrander, Elaine A.; Weikert, Steffen; Herkommer, Kathleen; Wahlfors, Tiina; Visakorpi, Tapio; Leinonen, Katri A.; Tammela, Teuvo L.J.; Cooper, Colin S.; Kote-Jarai, Zsofia; Edwards, Sandra; Goh, Chee L.; McCarthy, Frank; Parker, Chris; Flohr, Penny; Paulo, Paula; Jerónimo, Carmen; Henrique, Rui; Krause, Hans; Wach, Sven; Lieb, Verena; Rau, Tilman T.; Vogel, Walther; Kuefer, Rainer; Hofer, Matthias D.; Perner, Sven; Rubin, Mark A.; Agarwal, Archana M.; Easton, Doug F.; Al Olama, Ali Amin; Benlloch, Sara; Hoegel, Josef; Stanford, Janet L.

    2016-01-01

    Abstract Molecular and epidemiological differences have been described between TMPRSS2:ERG fusion-positive and fusion-negative prostate cancer (PrCa). Assuming two molecularly distinct subtypes, we have examined 27 common PrCa risk variants, previously identified in genome-wide association studies, for subtype specific associations in a total of 1221 TMPRSS2:ERG phenotyped PrCa cases. In meta-analyses of a discovery set of 552 cases with TMPRSS2:ERG data and 7650 unaffected men from five centers we have found support for the hypothesis that several common risk variants are associated with one particular subtype rather than with PrCa in general. Risk variants were analyzed in case-case comparisons (296 TMPRSS2:ERG fusion-positive versus 256 fusion-negative cases) and an independent set of 669 cases with TMPRSS2:ERG data was established to replicate the top five candidates. Significant differences (P < 0.00185) between the two subtypes were observed for rs16901979 (8q24) and rs1859962 (17q24), which were enriched in TMPRSS2:ERG fusion-negative (OR = 0.53, P = 0.0007) and TMPRSS2:ERG fusion-positive PrCa (OR = 1.30, P = 0.0016), respectively. Expression quantitative trait locus analysis was performed to investigate mechanistic links between risk variants, fusion status and target gene mRNA levels. For rs1859962 at 17q24, genotype dependent expression was observed for the candidate target gene SOX9 in TMPRSS2:ERG fusion-positive PrCa, which was not evident in TMPRSS2:ERG negative tumors. The present study established evidence for the first two common PrCa risk variants differentially associated with TMPRSS2:ERG fusion status. TMPRSS2:ERG phenotyping of larger studies is required to determine comprehensive sets of variants with subtype-specific roles in PrCa. PMID:27798103

  15. Trafficking-deficient hERG K+ channels linked to long QT syndrome are regulated by a microtubule-dependent quality control compartment in the ER

    PubMed Central

    Smith, Jennifer L.; McBride, Christie M.; Nataraj, Parvathi S.; Bartos, Daniel C.; January, Craig T.

    2011-01-01

    The human ether-a-go-go related gene (hERG) encodes the voltage-gated K+ channel that underlies the rapidly activating delayed-rectifier current in cardiac myocytes. hERG is synthesized in the endoplasmic reticulum (ER) as an “immature” N-linked glycoprotein and is terminally glycosylated in the Golgi apparatus. Most hERG missense mutations linked to long QT syndrome type 2 (LQT2) reduce the terminal glycosylation and functional expression. We tested the hypothesis that a distinct pre-Golgi compartment negatively regulates the trafficking of some LQT2 mutations to the Golgi apparatus. We found that treating cells in nocodazole, a microtubule depolymerizing agent, altered the subcellular localization, functional expression, and glycosylation of the LQT2 mutation G601S-hERG differently from wild-type hERG (WT-hERG). G601S-hERG quickly redistributed to peripheral compartments that partially colocalized with KDEL (Lys-Asp-Glu-Leu) chaperones but not calnexin, Sec31, or the ER golgi intermediate compartment (ERGIC). Treating cells in E-4031, a drug that increases the functional expression of G601S-hERG, prevented the accumulation of G601S-hERG to the peripheral compartments and increased G601S-hERG colocalization with the ERGIC. Coexpressing the temperature-sensitive mutant G protein from vesicular stomatitis virus, a mutant N-linked glycoprotein that is retained in the ER, showed it was not restricted to the same peripheral compartments as G601S-hERG at nonpermissive temperatures. We conclude that the trafficking of G601S-hERG is negatively regulated by a microtubule-dependent compartment within the ER. Identifying mechanisms that prevent the sorting or promote the release of LQT2 channels from this compartment may represent a novel therapeutic strategy for LQT2. PMID:21490315

  16. Exclusion of aldose reductase as a mediator of ERG deficits in a mouse model of diabetic eye disease.

    PubMed

    Samuels, Ivy S; Lee, Chieh-Allen; Petrash, J Mark; Peachey, Neal S; Kern, Timothy S

    2012-11-01

    Streptozotocin (STZ)-induced diabetes is associated with reductions in the electrical response of the outer retina and retinal pigment epithelium (RPE) to light. Aldose reductase (AR) is the first enzyme required in the polyol-mediated metabolism of glucose, and AR inhibitors have been shown to improve diabetes-induced electroretinogram (ERG) defects. Here, we used control and AR -/- mice to determine if genetic inactivation of this enzyme likewise inhibits retinal electrophysiological defects observed in a mouse model of type 1 diabetes. STZ was used to induce hyperglycemia and type 1 diabetes. Diabetic and age-matched nondiabetic controls of each genotype were maintained for 22 weeks, after which ERGs were used to measure the light-evoked components of the RPE (dc-ERG) and the neural retina (a-wave, b-wave). In comparison to their nondiabetic controls, wildtype (WT) and AR -/- diabetic mice displayed significant decreases in the c-wave, fast oscillation, and off response components of the dc-ERG but not in the light peak response. Nondiabetic AR -/- mice displayed larger ERG component amplitudes than did nondiabetic WT mice; however, the amplitude of dc-ERG components in diabetic AR -/- animals were similar to WT diabetics. ERG a-wave amplitudes were not reduced in either diabetic group, but b-wave amplitudes were lower in WT and AR -/-diabetic mice. These findings demonstrate that the light-induced responses of the RPE and outer retina are disrupted in diabetic mice, but these defects are not due to photoreceptor dysfunction, nor are they ameliorated by deletion of AR. This latter finding suggests that benefits observed in other studies utilizing pharmacological inhibitors of AR might have been secondary to off-target effects of the drugs.

  17. Quasiperiodic modulations of energetic electron fluxes in the ULF range observed by the ERG satellite

    NASA Astrophysics Data System (ADS)

    Teramoto, M.; Hori, T.; Kurita, S.; Yoshizumi, M.; Saito, S.; Higashio, N.; Mitani, T.; Matsuoka, A.; Park, I.; Takashima, T.; Nomura, R.; Nose, M.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Shinohara, I.

    2017-12-01

    Exploration of energization and Radiation in Geospace (ERG) satellite was successfully launched on December 20, 2016. The Extremely High-Energy Electron Experiment (XEP) and High-Energy Electron Experiments (HEP-L and HEP-H) are carried by the ERG satellite to observe energetic electrons. These instruments frequently observed quasiperiodic modulations of energetic electron fluxes with period of 100-600 sec. Continuous flux modulations with the period of 600 s appeared in the 700keV-3.6MeV energy range during the period 0920UT-1120UT on March 31, 2017 when the ERG satellite was located at L 5.5-6.1 and MLT 3-4 h. We compare these flux modulations with the magnetic field observed by the Magnetic Field Experiment (MGF) on the ERG satellite. It is found that these flux modulations are not accompanied by corresponding magnetic signatures. It indicates that these quasiperiodic flux modulations are not caused by drift-resonant interactions between ULF waves and energetic electrons, at least locally. In this study, we will show several events and discuss possible mechanism for quasiperiodic flux modulations of energetic electrons on XEP and HEP.

  18. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase (SAM:SMT)

    PubMed Central

    Kaneshiro, Edna S.; Johnston, Laura Q.; Nkinin, Stephenson W.; Romero, Becky I.; Giner, José-Luis

    2014-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The P. carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography (HPLC) and proton nuclear magnetic resonance spectroscopy (1H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ24(28)-sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii. PMID:25230683

  19. In silico design of novel hERG-neutral sildenafil-like PDE5 inhibitors.

    PubMed

    Kayık, Gülru; Tüzün, Nurcan Ş; Durdagi, Serdar

    2017-10-01

    Cyclic nucleotide phosphodiesterase enzymes (PDEs) have functions in regulating the levels of intracellular second messengers, 3', 5'-cyclic adenosine monophosphate (cAMP) and 3', 5'-cyclic guanosine monophosphate (cGMP), via hydrolysis and decomposing mechanisms in cells. They take essential roles in modulating various cellular activities such as memory and smooth muscle functions. PDE type 5 (PDE5) inhibitors enhance the vasodilatory effects of cGMP in the corpus cavernosum and they are used to treat erectile dysfunction. Patch clamp experiments showed that the IC 50 values of the human ether-à-go-go-related gene (hERG1) potassium (K) ion channel blocking affinity of PDE5 inhibitors sildenafil, vardenafil, and tadalafil as 33, 12, and 100 μM, respectively. hERG1 channel is responsible for the regulation of the action potential of human ventricular myocyte by contributing the rapid component of delayed rectifier K + current (I Kr ) component of the cardiac action potential. In this work, interaction patterns and binding affinity predictions of selected PDE5 inhibitors against the hERG1 channel are studied. It is attempted to develop PDE5 inhibitor analogs with lower binding affinity to hERG1 ion channel while keeping their pharmacological activity against their principal target PDE5 using in silico methods. Based on detailed analyses of docking poses and predicted interaction energies, novel analogs of PDE5 inhibitors with lower predicted binding affinity to hERG1 channels without loosing their principal target activity were proposed. Moreover, molecular dynamics (MD) simulations and post-processing MD analyses (i.e. Molecular Mechanics/Generalized Born Surface Area calculations) were performed. Detailed analysis of molecular simulations helped us to better understand the PDE5 inhibitor-target binding interactions in the atomic level. Results of this study can be useful for designing of novel and safe PDE5 inhibitors with enhanced activity and other tailored

  20. Transcription Factor Erg Variants and Functional Diversification of Chondrocytes during Limb Long Bone Development

    PubMed Central

    Iwamoto, Masahiro; Higuchi, Yoshinobu; Koyama, Eiki; Enomoto-Iwamoto, Motomi; Kurisu, Kojiro; Yeh, Helena; Abrams, William R.; Rosenbloom, Joel; Pacifici, Maurizio

    2000-01-01

    During limb development, chondrocytes located at the epiphyseal tip of long bone models give rise to articular tissue, whereas the more numerous chondrocytes in the shaft undergo maturation, hypertrophy, and mineralization and are replaced by bone cells. It is not understood how chondrocytes follow these alternative pathways to distinct fates and functions. In this study we describe the cloning of C-1-1, a novel variant of the ets transcription factor ch-ERG. C-1-1 lacks a short 27–amino acid segment located ∼80 amino acids upstream of the ets DNA binding domain. We found that in chick embryo long bone anlagen, C-1-1 expression characterizes developing articular chondrocytes, whereas ch-ERG expression is particularly prominent in prehypertrophic chondrocytes in the growth plate. To analyze the function of C-1-1 and ch-ERG, viral vectors were used to constitutively express each factor in developing chick leg buds and cultured chondrocytes. We found that virally driven expression of C-1-1 maintained chondrocytes in a stable and immature phenotype, blocked their maturation into hypertrophic cells, and prevented the replacement of cartilage with bone. It also induced synthesis of tenascin-C, an extracellular matrix protein that is a unique product of developing articular chondrocytes. In contrast, virally driven expression of ch-ERG significantly stimulated chondrocyte maturation in culture, as indicated by increases in alkaline phosphatase activity and deposition of a mineralized matrix; however, it had modest effects in vivo. The data show that C-1-1 and ch-ERG have diverse biological properties and distinct expression patterns during skeletogenesis, and are part of molecular mechanisms by which limb chondrocytes follow alternative developmental pathways. C-1-1 is the first transcription factor identified to date that appears to be instrumental in the genesis and function of epiphyseal articular chondrocytes. PMID:10893254

  1. Thermal behavior and ice-table depth within the north polar erg of Mars

    NASA Astrophysics Data System (ADS)

    Putzig, Nathaniel E.; Mellon, Michael T.; Herkenhoff, Kenneth E.; Phillips, Roger J.; Davis, Brian J.; Ewer, Kenneth J.; Bowers, Lauren M.

    2014-02-01

    We fully resolve a long-standing thermal discrepancy concerning the north polar erg of Mars. Several recent studies have shown that the erg's thermal properties are consistent with normal basaltic sand overlying shallow ground ice or ice-cemented sand. Our findings bolster that conclusion by thoroughly characterizing the thermal behavior of the erg, demonstrating that other likely forms of physical heterogeneity play only a minor role, and obviating the need to invoke exotic materials. Thermal inertia as calculated from orbital temperature observations of the dunes has previously been found to be more consistent with dust-sized materials than with sand. Since theory and laboratory data show that dunes will only form out of sand-sized particles, exotic sand-sized agglomerations of dust have been invoked to explain the low values of thermal inertia. However, the polar dunes exhibit the same darker appearance and color as that of dunes found elsewhere on the planet that have thermal inertia consistent with normal sand-sized basaltic grains, whereas Martian dust deposits are generally lighter and redder. The alternative explanation for the discrepancy as a thermal effect of a shallow ice table is supported by our analysis of observations from the Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System and by forward modeling of physical heterogeneity. In addition, our results exclude a uniform composition of dark dust-sized materials, and they show that the thermal effects of the dune slopes and bright interdune materials evident in high-resolution images cannot account for the erg's thermal behavior.

  2. On- and off-response ERGs elicited by sawtooth stimuli in normal subjects and glaucoma patients.

    PubMed

    Pangeni, Gobinda; Lämmer, Robert; Tornow, Ralf P; Horn, Folkert K; Kremers, Jan

    2012-06-01

    The aim of this study is to measure the on- and off-responses and their response asymmetries elicited by sawtooth stimuli in normal subjects and glaucoma patients. Furthermore, the correlation between the ERGs and other functional and structural parameters are investigated. Full-field stimuli were produced using a Ganzfeld bowl with Light Emitting Diodes (LEDs) as light sources. On- and off-response ERGs were recorded from 17 healthy subjects, 12 pre-perimetric and 15 perimetric glaucoma patients using 4-Hz luminance rapid-on and rapid-off sawtooth stimuli (white light; mean luminance 55 cd/m(2)) at 100% contrast. The on- and off-responses were added to study response asymmetries. In addition, flash ERGs were elicited by red stimuli (200 cd/m(2)) on a blue background (10 cd/m(2)). The mean deviations (MD) of the visual field defects were obtained by standard automated perimetry. The retinal nerve fibre layer thickness (RNFLT) was measured with Spectral Domain Optical Coherence Tomography (SOCT). We studied the correlation between ERG response amplitudes, visual field mean deviation (MDs) and RNFLT values. The on-responses showed an initial negative (N-on) followed by a positive (P-on), a late positive (LP-on) and a late negative responses (LN-on). The off-responses showed an initial positive (P-off) a late positive (LP-off) and a late negative response (LN-off). The addition of on- and off-responses revealed an initial positive (P-add) and a late negative response (LN-add). The on-response components (N-on, P-on and LN-on) in the glaucoma patients were relatively similar to those of the control subjects. However, the LP-on was significantly elevated (p = 0.03) in perimetric patients. The LP-off was significantly elevated (p < 0.001), and the amplitude of LN-off was significantly reduced in perimetric patients (p = 0.02). The LN-add amplitude was significantly reduced (p < 0.001) and delayed (p = 0.03) in perimetric patients. The amplitudes of the LN-off and LN

  3. Heterogeneity of PTEN and ERG expression in prostate cancer on core needle biopsies: implications for cancer risk stratification and biomarker sampling.

    PubMed

    Shah, Rajal B; Bentley, James; Jeffery, Zach; DeMarzo, Angelo M

    2015-05-01

    ERG and PTEN biomarkers are increasingly being analyzed on prostate core biopsies (NBXs); ERG as a marker of clonality and number of separately arising tumor foci and PTEN for prognostic information. Yet, in patients with multiple biopsy cores positive for cancer (PCa), there is no standardized approach for interrogation of these biomarkers in terms of the number of positive cores to evaluate. A total of 194 NBX cases containing more than one positive core with cancer were evaluated for ERG overexpression and PTEN loss by immunostaining (immunohistochemistry) of all positive cores. ERG overexpression or PTEN loss in at least one cancer core was present in 111 (57%) and 69 (36%) cases respectively. ERG overexpression was significantly associated with PTEN loss (P < .0001), and PTEN loss was associated with a high Gleason score (P < .0001). Inter- and intra-tumor core staining heterogeneity for ERG overexpression occurred in 42% and 5% cases and for PTEN loss both intra- and inter-tumor core heterogeneity was 68%. PTEN staining was highly discordant between PCa sites regardless of laterality. When the Gleason score was non-uniform across PCa sites, the combination of cores showing the highest Gleason score and largest tumor volume provided the best representation of ERG overexpression (92%) and PTEN loss (98%). When grades were uniform across cancer sites, the highest tumor volume core was generally representative of ERG overexpression (90%) but was less representative for PTEN loss (76%). Our results suggest that knowledge of this heterogeneity is critical for developing optimal yet cost-effective strategies to identify these underlying molecular abnormalities. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Histone deacetylase inhibitors, valproic acid and trichostatin-A induce apoptosis and affect acetylation status of p53 in ERG-positive prostate cancer cells

    PubMed Central

    FORTSON, WENDELL S.; KAYARTHODI, SHUBHALAXMI; FUJIMURA, YASUO; XU, HUALI; MATTHEWS, ROLAND; GRIZZLE, WILLIAM E.; RAO, VEENA N.; BHAT, GANAPATHY K.; REDDY, E. SHYAM P.

    2012-01-01

    An ETS family member, ETS Related Gene (ERG) is involved in the Ewing family of tumors as well as leukemias. Rearrangement of the ERG gene with the TMPRSS2 gene has been identified in the majority of prostate cancer patients. Additionally, overexpression of ERG is associated with un- favorable prognosis in prostate cancer patients similar to leukemia patients. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) regulate transcription as well as epigenetic status of genes through acetylation of both histones and transcription factors. Deregulation of HATs and HDACs is frequently seen in various cancers, including prostate cancer. Many cellular oncogenes as well as tumor viral proteins are known to target either or both HATs and HDACs. Several studies have demonstrated that there are alterations of HDAC activity in prostate cancer cells. Recently, we found that ERG binds and inhibits HATs, which suggests that ERG is involved in deregulation of protein acetylation. Additionally, it has been shown that ERG is associated with a higher expression of HDACs. In this study, we tested the effect of the HDAC inhibitors valproic acid (VPA) and trichostatin-A (TSA) on ERG-positive prostate cancer cells (VCaP). We found that VPA and TSA induce apoptosis, upregulate p21/Waf1/CIP1, repress TMPRSS2-ERG expression and affect acetylation status of p53 in VCaP cells. These results suggest that HDAC inhibitors might restore HAT activity through two different ways: by inhibiting HDAC activity and by repressing HAT targeting oncoproteins such as ERG. PMID:21519790

  5. Microwave remote sensing of Saharan ergs and Amazon vegetation

    NASA Astrophysics Data System (ADS)

    Stephen, Haroon

    This dissertation focuses on relating spaceborne microwave data to the geophysical characteristics of the Sahara desert and the Amazon vegetation. Radar and radiometric responses of the Saharan ergs are related to geophysical properties of sand formations and near surface winds. The spatial and temporal variability of the Amazon vegetation is studied using multi-frequency and multi-polarization data. The Sahara desert includes large expanses of sand dunes called ergs that are constantly reshaped by prevailing winds. Radar backscatter (sigma°) measurements observed at various incidence (theta) and azimuth (φ) angles from the NASA Scatterometer (NSCAT), the ERS scatterometer (ESCAT), the SeaWinds scatterometer aboard QuikScat (QSCAT), and the Precipitation Radar (TRMM-PR) aboard the Tropical Rain Monitoring Mission (TRMM) are used to model the sigma° response from sand dunes. Backscatter theta and φ variation depends upon the slopes and orientations of the dune slopes. Sand dunes are modeled as a composite of tilted rough facets, which are characterized by a probability distribution of tilt. The small ripples are modeled as cosinusoidal surface waves that contribute to the return signal at Bragg angles. The sigma° response is high at look angles equal to the mean tilts of the rough facets and is lower elsewhere. The modeled sigma° response is similar to NSCAT and ESCAT observations. sigma° also varies spatially and reflects the spatial inhomogeneity of the sand surface. A model incorporating the sigma° φ-modulation and spatial inhomogeneity is proposed. The maxima of the φ-modulation at theta = 33° reflect the orientation of the slip-sides on the sand surface. These slip-side orientations are consistent with the European Centre for Medium-Range Weather Forecasts wind directions spatially and temporally. Radiometric emissions from the ergs have strong dependence on the surface geometry. The radiometric temperature (Tb) of ergs is modeled as the weighted sum

  6. Rehabilitating drug-induced long-QT promoters: in-silico design of hERG-neutral cisapride analogues with retained pharmacological activity.

    PubMed

    Durdagi, Serdar; Randall, Trevor; Duff, Henry J; Chamberlin, Adam; Noskov, Sergei Y

    2014-03-08

    The human ether-a-go-go related gene 1 (hERG1), which codes for a potassium ion channel, is a key element in the cardiac delayed rectified potassium current, IKr, and plays an important role in the normal repolarization of the heart's action potential. Many approved drugs have been withdrawn from the market due to their prolongation of the QT interval. Most of these drugs have high potencies for their principal targets and are often irreplaceable, thus "rehabilitation" studies for decreasing their high hERG1 blocking affinities, while keeping them active at the binding sites of their targets, have been proposed to enable these drugs to re-enter the market. In this proof-of-principle study, we focus on cisapride, a gastroprokinetic agent withdrawn from the market due to its high hERG1 blocking affinity. Here we tested an a priori strategy to predict a compound's cardiotoxicity using de novo drug design with molecular docking and Molecular Dynamics (MD) simulations to generate a strategy for the rehabilitation of cisapride. We focused on two key receptors, a target interaction with the (adenosine) receptor and an off-target interaction with hERG1 channels. An analysis of the fragment interactions of cisapride at human A2A adenosine receptors and hERG1 central cavities helped us to identify the key chemical groups responsible for the drug activity and hERG1 blockade. A set of cisapride derivatives with reduced cardiotoxicity was then proposed using an in-silico two-tier approach. This set was compared against a large dataset of commercially available cisapride analogs and derivatives. An interaction decomposition of cisapride and cisapride derivatives allowed for the identification of key active scaffolds and functional groups that may be responsible for the unwanted blockade of hERG1.

  7. Rehabilitating drug-induced long-QT promoters: In-silico design of hERG-neutral cisapride analogues with retained pharmacological activity

    PubMed Central

    2014-01-01

    Background The human ether-a-go-go related gene 1 (hERG1), which codes for a potassium ion channel, is a key element in the cardiac delayed rectified potassium current, IKr, and plays an important role in the normal repolarization of the heart’s action potential. Many approved drugs have been withdrawn from the market due to their prolongation of the QT interval. Most of these drugs have high potencies for their principal targets and are often irreplaceable, thus “rehabilitation” studies for decreasing their high hERG1 blocking affinities, while keeping them active at the binding sites of their targets, have been proposed to enable these drugs to re-enter the market. Methods In this proof-of-principle study, we focus on cisapride, a gastroprokinetic agent withdrawn from the market due to its high hERG1 blocking affinity. Here we tested an a priori strategy to predict a compound’s cardiotoxicity using de novo drug design with molecular docking and Molecular Dynamics (MD) simulations to generate a strategy for the rehabilitation of cisapride. Results We focused on two key receptors, a target interaction with the (adenosine) receptor and an off-target interaction with hERG1 channels. An analysis of the fragment interactions of cisapride at human A2A adenosine receptors and hERG1 central cavities helped us to identify the key chemical groups responsible for the drug activity and hERG1 blockade. A set of cisapride derivatives with reduced cardiotoxicity was then proposed using an in-silico two-tier approach. This set was compared against a large dataset of commercially available cisapride analogs and derivatives. Conclusions An interaction decomposition of cisapride and cisapride derivatives allowed for the identification of key active scaffolds and functional groups that may be responsible for the unwanted blockade of hERG1. PMID:24606761

  8. Bag1 Co-chaperone Promotes TRC8 E3 Ligase-dependent Degradation of Misfolded Human Ether a Go-Go-related Gene (hERG) Potassium Channels.

    PubMed

    Hantouche, Christine; Williamson, Brittany; Valinsky, William C; Solomon, Joshua; Shrier, Alvin; Young, Jason C

    2017-02-10

    Cardiac long QT syndrome type 2 is caused by mutations in the human ether a go-go-related gene (hERG) potassium channel, many of which cause misfolding and degradation at the endoplasmic reticulum instead of normal trafficking to the cell surface. The Hsc70/Hsp70 chaperones assist the folding of the hERG cytosolic domains. Here, we demonstrate that the Hsp70 nucleotide exchange factor Bag1 promotes hERG degradation by the ubiquitin-proteasome system at the endoplasmic reticulum to regulate hERG levels and channel activity. Dissociation of hERG complexes containing Hsp70 and the E3 ubiquitin ligase CHIP requires the interaction of Bag1 with Hsp70, but this does not involve the Bag1 ubiquitin-like domain. The interaction with Bag1 then shifts hERG degradation to the membrane-anchored E3 ligase TRC8 and its E2-conjugating enzyme Ube2g2, as determined by siRNA screening. TRC8 interacts through the transmembrane region with hERG and decreases hERG functional expression. TRC8 also mediates degradation of the misfolded hERG-G601S disease mutant, but pharmacological stabilization of the mutant structure prevents degradation. Our results identify TRC8 as a previously unknown Hsp70-independent quality control E3 ligase for hERG. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. The Role of mf-ERG in the Diagnosis and Treatment of Age-Related Macular Degeneration: Electrophysiological Features of AMD.

    PubMed

    Moschos, Marilita M; Nitoda, Eirini

    2018-01-01

    Age-related macular cegeneration (AMD) is the leading cause of visual dysfunction worldwide, affecting 9-25% of individuals between 65 and 75 years old. We have reviewed the published articles investigating the role of multifocal electroretinogram (mf-ERG) in the diagnosis and treatment of AMD. Visual evoked potentials have revealed decreased amplitudes and higher latencies in patients with AMD, while the degeneration of photoreceptors and abnormalities of retinal pigment epithelium can be identified by electro-oculogram recordings. Moreover, ERG can detect the functional abnormalities observed in AMD and evaluate each therapeutic approach. The record of local electrophysiological responses coming from different retinal areas can be accurately performed by mfERG. The accuracy of mfERG in detecting the degeneration of photoreceptors, as well the disturbances of macular function, could be useful both in the early diagnosis of AMD and the assessment of treatment efficacy.

  10. Application of Wave Distribution Function Method to the ERG/PWE Data

    NASA Astrophysics Data System (ADS)

    Ota, M.; Kasahara, Y.; Matsuda, S.; Kojima, H.; Matsuoka, A.; Hikishima, M.; Kasaba, Y.; Ozaki, M.; Yagitani, S.; Tsuchiya, F.; Kumamoto, A.

    2017-12-01

    The ERG (Arase) satellite was launched on 20 December 2016 to study acceleration and loss mechanisms of relativistic electrons in the Earth's magnetosphere. The Plasma Wave Experiment (PWE), which is one of the science instruments on board the ERG satellite, measures electric field and magnetic field. The PWE consists of three sub-systems; EFD (Electric Field Detector), OFA/WFC (Onboard Frequency Analyzer and Waveform Capture), and HFA (High Frequency Analyzer).The OFA/WFC measures electromagnetic field spectra and raw waveforms in the frequency range from few Hz to 20 kHz. The OFA produces three kind of data; OFA-SPEC (power spectrum), OFA-MATRIX (spectral matrix), and OFA-COMPLEX (complex spectrum). The OFA-MATRIX measures ensemble averaged complex cross-spectra of two electric field components, and of three magnetic field components. The OFA-COMPLEX measures instantaneous complex spectra of electric and magnetic fields. These data are produced every 8 seconds in the nominal mode, and it can be used for polarization analysis and wave propagation direction finding.In general, spectral matrix composed by cross-spectra of observed signals is used for direction finding, and many algorithms have been proposed. For example, Means method and SVD method can be applied on the assumption that the spectral matrix is consists of a single plane wave, while wave distribution function (WDF) method is applicable even to the data in which multiple numbers of plane waves are simultaneously included. In this presentation, we introduce the results when the WDF method is applied to the ERG/PWE data.

  11. Cell Surface Expression of Human Ether-a-go-go-related Gene (hERG) Channels Is Regulated by Caveolin-3 Protein via the Ubiquitin Ligase Nedd4-2*

    PubMed Central

    Guo, Jun; Wang, Tingzhong; Li, Xian; Shallow, Heidi; Yang, Tonghua; Li, Wentao; Xu, Jianmin; Fridman, Michael D.; Yang, Xiaolong; Zhang, Shetuan

    2012-01-01

    The human ether-a-go-go-related gene (hERG) encodes the rapidly activating delayed rectifier potassium channel (IKr) which plays an important role in cardiac repolarization. A reduction or increase in hERG current can cause long or short QT syndrome, respectively, leading to fatal cardiac arrhythmias. The channel density in the plasma membrane is a key determinant of the whole cell current amplitude. To gain insight into the molecular mechanisms for the regulation of hERG density at the plasma membrane, we used whole cell voltage clamp, Western blotting, and immunocytochemical methods to investigate the effects of an integral membrane protein, caveolin-3 (Cav3) on hERG expression levels. Our data demonstrate that Cav3, hERG, and ubiquitin-ligase Nedd4-2 interact with each other and form a complex. Expression of Cav3 thus enhances the hERG-Nedd4-2 interaction, leading to an increased ubiquitination and degradation of mature, plasma-membrane localized hERG channels. Disrupting Nedd4-2 interaction with hERG by mutations eliminates the effects of Cav3 on hERG channels. Knockdown of endogenous Cav3 or Nedd4-2 in cultured neonatal rat ventricular myocytes using siRNA led to an increase in native IKr. Our data demonstrate that hERG expression in the plasma membrane is regulated by Cav3 via Nedd4-2. These findings extend our understanding of the regulation of hERG channels and cardiac electrophysiology. PMID:22879586

  12. Acute macular neuroretinopathy: contribution of spectral-domain optical coherence tomography and multifocal ERG.

    PubMed

    Maschi, Célia; Schneider-Lise, Bérengère; Paoli, Vincent; Gastaud, Pierre

    2011-06-01

    Acute macular neuroretinopathy is a rare disease which occurs in young women and causes sudden paracentral scotoma and typical reddish-brown macular lesions. We report two cases of young women suffering from acute macular neuroretinopathy which we observed with spectral-domain Spectralis HRA-OCT and multifocal ERG at 3 and 7 months. Imaging revealed an early hyper-reflectivity of the photoreceptor layer, which changed into hyporeflectivity in the first week and remained the same in the following months, whereas visual field improved. Our findings show involvement primarly of the outer retina, and confirm OCT and mf ERG as important tools for diagnosis and follow-up of pathologic changes in AMNR, as other diagnostic tests often remain normal.

  13. The effects of deoxyelephantopin on the cardiac delayed rectifier potassium channel current (IKr) and human ether-a-go-go-related gene (hERG) expression.

    PubMed

    Teah, Yi Fan; Abduraman, Muhammad Asyraf; Amanah, Azimah; Adenan, Mohd Ilham; Sulaiman, Shaida Fariza; Tan, Mei Lan

    2017-09-01

    Elephantopus scaber Linn and its major bioactive component, deoxyelephantopin are known for their medicinal properties and are often reported to have various cytotoxic and antitumor activities. This plant is widely used as folk medicine for a plethora of indications although its safety profile remains unknown. Human ether-a-go-go-related gene (hERG) encodes the cardiac I Kr current which is a determinant of the duration of ventricular action potentials and QT interval. The hERG potassium channel is an important antitarget in cardiotoxicity evaluation. This study investigated the effects of deoxyelephantopin on the current, mRNA and protein expression of hERG channel in hERG-transfected HEK293 cells. The hERG tail currents following depolarization pulses were insignificantly affected by deoxyelephantopin in the transfected cell line. Current reduction was less than 40% as compared with baseline at the highest concentration of 50 μM. The results were consistent with the molecular docking simulation and hERG surface protein expression. Interestingly, it does not affect the hERG expression at both transcriptional and translational level at most concentrations, although higher concentration at 10 μM caused protein accumulation. In conclusion, deoxyelephantopin is unlikely a clinically significant hERG channel and I kr blocker. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A quantitative proteomics approach identifies ETV6 and IKZF1 as new regulators of an ERG-driven transcriptional network

    PubMed Central

    Unnikrishnan, Ashwin; Guan, Yi F.; Huang, Yizhou; Beck, Dominik; Thoms, Julie A. I.; Peirs, Sofie; Knezevic, Kathy; Ma, Shiyong; de Walle, Inge V.; de Jong, Ineke; Ali, Zara; Zhong, Ling; Raftery, Mark J.; Taghon, Tom; Larsson, Jonas; MacKenzie, Karen L.; Van Vlierberghe, Pieter; Wong, Jason W. H.; Pimanda, John E.

    2016-01-01

    Aberrant stem cell-like gene regulatory networks are a feature of leukaemogenesis. The ETS-related gene (ERG), an important regulator of normal haematopoiesis, is also highly expressed in T-ALL and acute myeloid leukaemia (AML). However, the transcriptional regulation of ERG in leukaemic cells remains poorly understood. In order to discover transcriptional regulators of ERG, we employed a quantitative mass spectrometry-based method to identify factors binding the 321 bp ERG +85 stem cell enhancer region in MOLT-4 T-ALL and KG-1 AML cells. Using this approach, we identified a number of known binders of the +85 enhancer in leukaemic cells along with previously unknown binders, including ETV6 and IKZF1. We confirmed that ETV6 and IKZF1 were also bound at the +85 enhancer in both leukaemic cells and in healthy human CD34+ haematopoietic stem and progenitor cells. Knockdown experiments confirmed that ETV6 and IKZF1 are transcriptional regulators not just of ERG, but also of a number of genes regulated by a densely interconnected network of seven transcription factors. At last, we show that ETV6 and IKZF1 expression levels are positively correlated with expression of a number of heptad genes in AML and high expression of all nine genes confers poorer overall prognosis. PMID:27604872

  15. hERG1 channels are overexpressed in glioblastoma multiforme and modulate VEGF secretion in glioblastoma cell lines

    PubMed Central

    Masi, A; Becchetti, A; Restano-Cassulini, R; Polvani, S; Hofmann, G; Buccoliero, A M; Paglierani, M; Pollo, B; Taddei, G L; Gallina, P; Di Lorenzo, N; Franceschetti, S; Wanke, E; Arcangeli, A

    2005-01-01

    Recent studies have led to considerable advancement in our understanding of the molecular mechanisms that underlie the relentless cell growth and invasiveness of human gliomas. Partial understanding of these mechanisms has (1) improved the classification for gliomas, by identifying prognostic subgroups, and (2) pointed to novel potential therapeutic targets. Some classes of ion channels have turned out to be involved in the pathogenesis and malignancy of gliomas. We studied the expression and properties of K+ channels in primary cultures obtained from surgical specimens: human ether a gò-gò related (hERG)1 voltage-dependent K+ channels, which have been found to be overexpressed in various human cancers, and human ether a gò-gò-like 2 channels, that share many of hERG1's biophysical features. The expression pattern of these two channels was compared to that of the classical inward rectifying K+ channels, IRK, that are widely expressed in astrocytic cells and classically considered a marker of astrocytic differentiation. In our study, hERG1 was found to be specifically overexpressed in high-grade astrocytomas, that is, glioblastoma multiforme (GBM). In addition, we present evidence that, in GBM cell lines, hERG1 channel activity actively contributes to malignancy by promoting vascular endothelial growth factor secretion, thus stimulating the neoangiogenesis typical of high-grade gliomas. Our data provide important confirmation for studies proposing the hERG1 channel as a molecular marker of tumour progression and a possible target for novel anticancer therapies. PMID:16175187

  16. Photopic ERG negative response from amacrine cell signaling in RCS rat retinal degeneration.

    PubMed

    Machida, Shigeki; Raz-Prag, Dorit; Fariss, Robert N; Sieving, Paul A; Bush, Ronald A

    2008-01-01

    The authors investigated photopic electroretinographic changes during degeneration in the Royal College of Surgeons (RCS) and transgenic P23H rhodopsin rat models, including the cellular origins of a large corneal-negative component that persists in the RCS rat. Photopic and scotopic electroretinograms (ERGs) were recorded from dystrophic RCS (RCS-p(+)/Lav) rats (4-18 weeks old) and transgenic rhodopsin Pro23His line 1 (P23H) rats (4-30 weeks old). Age-matched congenic (RCS-rdy(+)p(+)/Lav) and Sprague-Dawley rats were used as controls. N-methyl-DL-aspartic acid (NMA), dopamine, and gamma-aminobutyric acid (GABA) were injected intravitreally, and optic nerve sectioning (ONS) was performed to suppress or remove inner retinal neuron activity. Retinal morphology for cone cell counts and immunohistochemistry for quantification of Kir4.1 channels were performed at various stages of degeneration. As degeneration progressed, the photopic ERG of RCS dystrophic rats was distinctly different from that of P23H rats, primarily because of the growth of a corneal-negative response (RCS-NPR) after the b-wave in RCS rats. This response had a peak time similar to the photopic negative response (PhNR) in controls but with a more gradual recovery phase, and it was not affected by ONS. The PhNR in P23H rats declined linearly with the b-wave. NMA and GABA eliminated the RCS-NPR and uncovered a larger b-wave in RCS rats at late stages of degeneration, but NMA had little effect on the ERG in P23H rats. The NMA-sensitive negative response in RCS rats declined with age more slowly than did the NMA-isolated b-wave. The density of Kir4.1 channels at the endfeet of Müller cells and in the proximal retina increased significantly between 6 to 10 weeks and 14 weeks of age in the RCS rat retina but not in the P23H rat retina. The photopic ERG of the dystrophic RCS rat retina becomes increasingly electronegative because of an aberrant negative response, originating from amacrine cell activity

  17. Mitigating hERG Inhibition: Design of Orally Bioavailable CCR5 Antagonists as Potent Inhibitors of R5 HIV-1 Replication

    PubMed Central

    2012-01-01

    A series of CCR5 antagonists representing the thiophene-3-yl-methyl ureas were designed that met the pharmacological criteria for HIV-1 inhibition and mitigated a human ether-a-go-go related gene (hERG) inhibition liability. Reducing lipophilicity was the main design criteria used to identify compounds that did not inhibit the hERG channel, but subtle structural modifications were also important. Interestingly, within this series, compounds with low hERG inhibition prolonged the action potential duration (APD) in dog Purkinje fibers, suggesting a mixed effect on cardiac ion channels. PMID:24900457

  18. Evaluation of ERG and SPINK1 by Immunohistochemical Staining and Clinicopathological Outcomes in a Multi-Institutional Radical Prostatectomy Cohort of 1067 Patients.

    PubMed

    Brooks, James D; Wei, Wei; Hawley, Sarah; Auman, Heidi; Newcomb, Lisa; Boyer, Hilary; Fazli, Ladan; Simko, Jeff; Hurtado-Coll, Antonio; Troyer, Dean A; Carroll, Peter R; Gleave, Martin; Lance, Raymond; Lin, Daniel W; Nelson, Peter S; Thompson, Ian M; True, Lawrence D; Feng, Ziding; McKenney, Jesse K

    2015-01-01

    Distinguishing between patients with early stage, screen detected prostate cancer who must be treated from those that can be safely watched has become a major issue in prostate cancer care. Identification of molecular subtypes of prostate cancer has opened the opportunity for testing whether biomarkers that characterize these subtypes can be used as biomarkers of prognosis. Two established molecular subtypes are identified by high expression of the ERG oncoprotein, due to structural DNA alterations that encode for fusion transcripts in approximately ½ of prostate cancers, and over-expression of SPINK1, which is purportedly found only in ERG-negative tumors. We used a multi-institutional prostate cancer tissue microarray constructed from radical prostatectomy samples with associated detailed clinical data and with rigorous selection of recurrent and non-recurrent cases to test the prognostic value of immunohistochemistry staining results for the ERG and SPINK1 proteins. In univariate analysis, ERG positive cases (419/1067; 39%) were associated with lower patient age, pre-operative serum PSA levels, lower Gleason scores (≤ 3+4=7) and improved recurrence free survival (RFS). On multivariate analysis, ERG status was not correlated with RFS, disease specific survival (DSS) or overall survival (OS). High-level SPINK1 protein expression (33/1067 cases; 3%) was associated with improved RFS on univariate and multivariate Cox regression analysis. Over-expression of either protein was not associated with clinical outcome. While expression of ERG and SPINK1 proteins was inversely correlated, it was not mutually exclusive since 3 (0.28%) cases showed high expression of both. While ERG and SPINK1 appear to identify discrete molecular subtypes of prostate cancer, only high expression of SPINK1 was associated with improved clinical outcome. However, by themselves, neither ERG nor SPINK1 appear to be useful biomarkers for prognostication of early stage prostate cancer.

  19. Evaluation of ERG and SPINK1 by Immunohistochemical Staining and Clinicopathological Outcomes in a Multi-Institutional Radical Prostatectomy Cohort of 1067 Patients

    PubMed Central

    Brooks, James D.; Wei, Wei; Hawley, Sarah; Auman, Heidi; Newcomb, Lisa; Boyer, Hilary; Fazli, Ladan; Simko, Jeff; Hurtado-Coll, Antonio; Troyer, Dean A.; Carroll, Peter R.; Gleave, Martin; Lance, Raymond; Lin, Daniel W.; Nelson, Peter S.; Thompson, Ian M.; True, Lawrence D.; Feng, Ziding; McKenney, Jesse K.

    2015-01-01

    Distinguishing between patients with early stage, screen detected prostate cancer who must be treated from those that can be safely watched has become a major issue in prostate cancer care. Identification of molecular subtypes of prostate cancer has opened the opportunity for testing whether biomarkers that characterize these subtypes can be used as biomarkers of prognosis. Two established molecular subtypes are identified by high expression of the ERG oncoprotein, due to structural DNA alterations that encode for fusion transcripts in approximately ½ of prostate cancers, and over-expression of SPINK1, which is purportedly found only in ERG-negative tumors. We used a multi-institutional prostate cancer tissue microarray constructed from radical prostatectomy samples with associated detailed clinical data and with rigorous selection of recurrent and non-recurrent cases to test the prognostic value of immunohistochemistry staining results for the ERG and SPINK1 proteins. In univariate analysis, ERG positive cases (419/1067; 39%) were associated with lower patient age, pre-operative serum PSA levels, lower Gleason scores (≤3+4=7) and improved recurrence free survival (RFS). On multivariate analysis, ERG status was not correlated with RFS, disease specific survival (DSS) or overall survival (OS). High-level SPINK1 protein expression (33/1067 cases; 3%) was associated with improved RFS on univariate and multivariate Cox regression analysis. Over-expression of either protein was not associated with clinical outcome. While expression of ERG and SPINK1 proteins was inversely correlated, it was not mutually exclusive since 3 (0.28%) cases showed high expression of both. While ERG and SPINK1 appear to identify discrete molecular subtypes of prostate cancer, only high expression of SPINK1 was associated with improved clinical outcome. However, by themselves, neither ERG nor SPINK1 appear to be useful biomarkers for prognostication of early stage prostate cancer. PMID

  20. Development of a High-Throughput Flow Cytometry Assay to Monitor Defective Trafficking and Rescue of Long QT2 Mutant hERG Channels

    PubMed Central

    Kanner, Scott A.; Jain, Ananya; Colecraft, Henry M.

    2018-01-01

    Long QT Syndrome (LQTS) is an acquired or inherited disorder characterized by prolonged QT interval, exertion-triggered arrhythmias, and sudden cardiac death. One of the most prevalent hereditary LQTS subtypes, LQT2, results from loss-of-function mutations in the hERG channel, which conducts IKr, the rapid component of the delayed rectifier K+ current, critical for cardiac repolarization. The majority of LQT2 mutations result in Class 2 deficits characterized by impaired maturation and trafficking of hERG channels. Here, we have developed a high-throughput flow cytometric assay to analyze the surface and total expression of wild-type (WT) and mutant hERG channels with single-cell resolution. To test our method, we focused on 16 LQT2 mutations in the hERG Per-Arnt-Sim (PAS) domain that were previously studied via a widely used biochemical approach that compares levels of 135-kDa immature and 155-kDa fully glycosylated hERG protein to infer surface expression. We confirmed that LQT2 mutants expressed in HEK293 cells displayed a decreased surface density compared to WT hERG, and were differentially rescued by low temperature. However, we also uncovered some notable differences from the findings obtained via the biochemical approach. In particular, three mutations (N33T, R56Q, and A57P) with apparent WT-like hERG glycosylation patterns displayed up to 50% decreased surface expression. Furthermore, despite WT-like levels of complex glycosylation, these mutants have impaired forward trafficking, and exhibit varying half-lives at the cell surface. The results highlight utility of the surface labeling/flow cytometry approach to quantitatively assess trafficking deficiencies associated with LQT2 mutations, to discern underlying mechanisms, and to report on interventions that rescue deficits in hERG surface expression. PMID:29725305

  1. Overexpression of Both ERG11 and ABC2 Genes Might Be Responsible for Itraconazole Resistance in Clinical Isolates of Candida krusei

    PubMed Central

    He, Xiaoyuan; Zhao, Mingfeng; Chen, Jinyan; Wu, Rimao; Zhang, Jianlei; Cui, Rui; Jiang, Yanyu; Chen, Jie; Cao, Xiaoli; Xing, Yi; Zhang, Yuchen; Meng, Juanxia; Deng, Qi; Sui, Tao

    2015-01-01

    Objective To study the main molecular mechanisms responsible for itraconazole resistance in clinical isolates of Candida krusei. Methods The 14α-demethylases encoded by ERG11 gene in the 16 C.krusei clinical isolates were amplified by polymerase chain reaction (PCR), and their nucleotide sequences were determined to detect point mutations. Meanwhile, ERG11 and efflux transporters (ABC1 and ABC2) genes were determined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) for their expression in itraconazole-resistant (R), itraconazole-susceptible dose dependent (SDD) and itraconazole-susceptible (S) C.krusei at the mRNA level. Results We found 7-point mutations in ERG11 gene of all the C.krusei clinical isolates, including 6 synonymous mutations and 1 missense mutation (C44T). However, the missense mutation was found in the three groups. The mRNA levels of ERG11 gene in itraconazole-resistant isolates showed higher expression compared with itraconazole-susceptible dose dependent and itraconazole-susceptible ones (P = 0.015 and P = 0.002 respectively). ABC2 gene mRNA levels in itraconazole-resistant group was significantly higher than the other two groups, and the levels of their expression in the isolates appeared to increase with the decrease of susceptibility to itraconazole (P = 0.007 in SDD compared with S, P = 0.016 in SDD with R, and P<0.001 in S with R respectively). While ABC1 gene presented lower expression in itraconazole resistant strains. However, the mRNA levels of ERG11, ABC1 and ABC2 in a C.krusei (CK10) resistant to both itraconazole and voriconazole were expressed highest in all the itraconazole-resistant isolates. Conclusions There are ERG11 gene polymorphisms in clinical isolates of C.krusei. ERG11 gene mutations may not be involved in the development of itraconazole resistance in C.krusei. ERG11 and ABC2 overexpression might be responsible for the acquired itraconazole resistance of these clinical isolates. PMID

  2. MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress.

    PubMed

    Wang, Qi; Hu, Weina; Lei, Mingming; Wang, Yong; Yan, Bing; Liu, Jun; Zhang, Ren; Jin, Yuanzhe

    2013-01-01

    To investigate if microRNAs (miRNAs) play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders. We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+) current. H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2), with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking. Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.

  3. Modeling the Mechanism of GR/c-Jun/Erg Crosstalk in Apoptosis of Acute Lymphoblastic Leukemia

    PubMed Central

    Chen, Daphne Wei-Chen; Krstic-Demonacos, Marija; Schwartz, Jean-Marc

    2012-01-01

    Acute lymphoblastic leukemia (ALL) is one of the most common forms of malignancy that occurs in lymphoid progenitor cells, particularly in children. Synthetic steroid hormones glucocorticoids (GCs) are widely used as part of the ALL treatment regimens due to their apoptotic function, but their use also brings about various side effects and drug resistance. The identification of the molecular differences between the GCs responsive and resistant cells therefore are essential to decipher such complexity and can be used to improve therapy. However, the emerging picture is complicated as the activities of genes and proteins involved are controlled by multiple factors. By adopting the systems biology framework to address this issue, we here integrated the available knowledge together with experimental data by building a series of mathematical models. This rationale enabled us to unravel molecular interactions involving c-Jun in GC induced apoptosis and identify Ets-related gene (Erg) as potential biomarker of GC resistance. The results revealed an alternative possible mechanism where c-Jun may be an indirect GR target that is controlled via an upstream repressor protein. The models also highlight the importance of Erg for GR function, particularly in GC sensitive C7 cells where Erg directly regulates GR in agreement with our previous experimental results. Our models describe potential GR-controlled molecular mechanisms of c-Jun/Bim and Erg regulation. We also demonstrate the importance of using a systematic approach to translate human disease processes into computational models in order to derive information-driven new hypotheses. PMID:23181019

  4. Modeling the Mechanism of GR/c-Jun/Erg Crosstalk in Apoptosis of Acute Lymphoblastic Leukemia.

    PubMed

    Chen, Daphne Wei-Chen; Krstic-Demonacos, Marija; Schwartz, Jean-Marc

    2012-01-01

    Acute lymphoblastic leukemia (ALL) is one of the most common forms of malignancy that occurs in lymphoid progenitor cells, particularly in children. Synthetic steroid hormones glucocorticoids (GCs) are widely used as part of the ALL treatment regimens due to their apoptotic function, but their use also brings about various side effects and drug resistance. The identification of the molecular differences between the GCs responsive and resistant cells therefore are essential to decipher such complexity and can be used to improve therapy. However, the emerging picture is complicated as the activities of genes and proteins involved are controlled by multiple factors. By adopting the systems biology framework to address this issue, we here integrated the available knowledge together with experimental data by building a series of mathematical models. This rationale enabled us to unravel molecular interactions involving c-Jun in GC induced apoptosis and identify Ets-related gene (Erg) as potential biomarker of GC resistance. The results revealed an alternative possible mechanism where c-Jun may be an indirect GR target that is controlled via an upstream repressor protein. The models also highlight the importance of Erg for GR function, particularly in GC sensitive C7 cells where Erg directly regulates GR in agreement with our previous experimental results. Our models describe potential GR-controlled molecular mechanisms of c-Jun/Bim and Erg regulation. We also demonstrate the importance of using a systematic approach to translate human disease processes into computational models in order to derive information-driven new hypotheses.

  5. Ets-1 promoter-associated noncoding RNA regulates the NONO/ERG/Ets-1 axis to drive gastric cancer progression.

    PubMed

    Li, Dan; Chen, Yajun; Mei, Hong; Jiao, Wanju; Song, Huajie; Ye, Lin; Fang, Erhu; Wang, Xiaojing; Yang, Feng; Huang, Kai; Zheng, Liduan; Tong, Qiangsong

    2018-05-18

    Emerging studies have indicated the essential functions of long noncoding RNAs (lncRNAs) during cancer progression. However, whether lncRNAs contribute to the upregulation of v-ets erythroblastosis virus E26 oncogene homolog 1 (Ets-1), an established oncogenic protein facilitating tumor invasion and metastasis, in gastric cancer remains elusive. Herein, we identified Ets-1 promoter-associated noncoding RNA (pancEts-1) as a novel lncRNA associated with the gastric cancer progression via mining of publicly available datasets and rapid amplification of cDNA ends. RNA pull-down, RNA immunoprecipitation, in vitro binding, and RNA electrophoretic mobility shift assays indicated the binding of pancEts-1 to non-POU domain containing octamer binding (NONO) protein. Mechanistically, pancEts-1 facilitated the physical interaction between NONO and Ets related gene (ERG), resulting in increased ERG transactivation and transcription of Ets-1 associated with gastric cancer progression. In addition, pancEts-1 facilitated the growth and aggressiveness of gastric cancer cells via interacting with NONO. In gastric cancer tissues, pancEts-1, NONO, and ERG were upregulated and significantly correlated with Ets-1 levels. High levels of pancEts-1, NONO, ERG, or Ets-1 were respectively associated with poor survival of gastric cancer patients, whereas simultaneous expression of all of them (HR = 3.012, P = 0.105) was not an independent prognostic factor for predicting clinical outcome. Overall, these results demonstrate that lncRNA pancEts-1 exhibits oncogenic properties that drive the progression of gastric cancer via regulating the NONO/ERG/Ets-1 axis.

  6. MicroRNA-224 targets ERG2 and contributes to malignant progressions of meningioma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Maomao; Deng, Xiaodong; Ying, Qi

    2015-05-01

    MicroRNA-224 is overexpressed in various malignant tumors with poor prognosis, which plays a critical role in biological processes including cell proliferation, apoptosis and several developmental and physiological progressions. However, the potential association between miR-224 and clinical outcome in patients with meningiomas remains unknown. Here, we investigate miR-224 expression and biological functions in meningiomas. MiR-224 expression was measured by Northern blot analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in meningioma and normal brain tissues. Kaplan–Meier analysis and Cox regression analysis were used to exam its correlation with clinicopathological features and prognostic value. The biological effects of miR-224 on the cellmore » proliferation and apoptosis in meningioma cells were examined by MTT assay and apoptosis assay. We found the expression levels of miR-224 were significantly higher in meningioma tissues than that in normal brain, positively correlated with advanced pathological grade. Kaplan–Meier analysis indicated that meningioma patients with low miR-224 expression exhibited significantly prolonged overall and recurrence-free survival. Furthermore, we demonstrated that ERG2 was an identical candidate target gene of MiR-224 in vitro. Our results indicated that downregulation of miR-224 suppressed cell growth and resulted in the enhancement of cell apoptosis through activation of the ERG2-BAK-induced apoptosis pathway. Our findings imply the miR-224 expression could predict the overall survival and recurrence-free survival of patients with meningioma and it might be a promising therapeutic target for treating malignant meningiomas. - Highlights: • MiR-224 expression is correlates with prognosis in meningioma patients. • ERG2 is a novel downstream target of miR-224. • MiR-224 suppressed cell growth and enhanced apoptosis in IOMM-Lee and CH157 cells. • MiR-224 is an upstream regulator of

  7. Mechanisms of zolpidem-induced long QT syndrome: acute inhibition of recombinant hERG K+ channels and action potential prolongation in human cardiomyocytes derived from induced pluripotent stem cells

    PubMed Central

    Jehle, J; Ficker, E; Wan, X; Deschenes, I; Kisselbach, J; Wiedmann, F; Staudacher, I; Schmidt, C; Schweizer, PA; Becker, R; Katus, HA; Thomas, D

    2013-01-01

    Background and Purpose Zolpidem, a short-acting hypnotic drug prescribed to treat insomnia, has been clinically associated with acquired long QT syndrome (LQTS) and torsade de pointes (TdP) tachyarrhythmia. LQTS is primarily attributed to reduction of cardiac human ether-a-go-go-related gene (hERG)/IKr currents. We hypothesized that zolpidem prolongs the cardiac action potential through inhibition of hERG K+ channels. Experimental Approach Two-electrode voltage clamp and whole-cell patch clamp electrophysiology was used to record hERG currents from Xenopus oocytes and from HEK 293 cells. In addition, hERG protein trafficking was evaluated in HEK 293 cells by Western blot analysis, and action potential duration (APD) was assessed in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. Key Results Zolpidem caused acute hERG channel blockade in oocytes (IC50 = 61.5 μM) and in HEK 293 cells (IC50 = 65.5 μM). Mutation of residues Y652 and F656 attenuated hERG inhibition, suggesting drug binding to a receptor site inside the channel pore. Channels were blocked in open and inactivated states in a voltage- and frequency-independent manner. Zolpidem accelerated hERG channel inactivation but did not affect I–V relationships of steady-state activation and inactivation. In contrast to the majority of hERG inhibitors, hERG cell surface trafficking was not impaired by zolpidem. Finally, acute zolpidem exposure resulted in APD prolongation in hiPSC-derived cardiomyocytes. Conclusions and Implications Zolpidem inhibits cardiac hERG K+ channels. Despite a relatively low affinity of zolpidem to hERG channels, APD prolongation may lead to acquired LQTS and TdP in cases of reduced repolarization reserve or zolpidem overdose. PMID:23061993

  8. Vacancy-ordering effects in AlB2-type ErGe2 - x(0.4 < x < or = 0.5).

    PubMed

    Christensen, Jeppe; Lidin, Sven; Malaman, Bernard; Venturini, Gerard

    2008-06-01

    In the Er-Ge system, the compostion range ErGe(2) to Er(2)Ge(3) has been investigated. Eight samples were produced by arc melting of the elements, and analyzed using X-ray powder diffraction. Nine crystal structures were found to be present in the samples. The structures are described as a homologous series and presented within the superspace formalism using the superspace group X2/m(alpha0gamma)0s, X representing the centring vector ((1/2), (1/2), 0, (1/2)). In this description the modulation vector q = (alphaa* + gammac*) is shown to be a direct measure of the Ge content as ErGe(2 - alpha) (alpha falls in the range 1\\over 3 to (1/2)). The large composition range is achieved by extended vacancy ordering in the planar 6(3) net of Ge with subsequent relaxation.

  9. A human ether-á-go-go-related (hERG) ion channel atomistic model generated by long supercomputer molecular dynamics simulations and its use in predicting drug cardiotoxicity.

    PubMed

    Anwar-Mohamed, Anwar; Barakat, Khaled H; Bhat, Rakesh; Noskov, Sergei Y; Tyrrell, D Lorne; Tuszynski, Jack A; Houghton, Michael

    2014-11-04

    Acquired cardiac long QT syndrome (LQTS) is a frequent drug-induced toxic event that is often caused through blocking of the human ether-á-go-go-related (hERG) K(+) ion channel. This has led to the removal of several major drugs post-approval and is a frequent cause of termination of clinical trials. We report here a computational atomistic model derived using long molecular dynamics that allows sensitive prediction of hERG blockage. It identified drug-mediated hERG blocking activity of a test panel of 18 compounds with high sensitivity and specificity and was experimentally validated using hERG binding assays and patch clamp electrophysiological assays. The model discriminates between potent, weak, and non-hERG blockers and is superior to previous computational methods. This computational model serves as a powerful new tool to predict hERG blocking thus rendering drug development safer and more efficient. As an example, we show that a drug that was halted recently in clinical development because of severe cardiotoxicity is a potent inhibitor of hERG in two different biological assays which could have been predicted using our new computational model. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Voltage-sensing domain mode shift is coupled to the activation gate by the N-terminal tail of hERG channels.

    PubMed

    Tan, Peter S; Perry, Matthew D; Ng, Chai Ann; Vandenberg, Jamie I; Hill, Adam P

    2012-09-01

    Human ether-a-go-go-related gene (hERG) potassium channels exhibit unique gating kinetics characterized by unusually slow activation and deactivation. The N terminus of the channel, which contains an amphipathic helix and an unstructured tail, has been shown to be involved in regulation of this slow deactivation. However, the mechanism of how this occurs and the connection between voltage-sensing domain (VSD) return and closing of the gate are unclear. To examine this relationship, we have used voltage-clamp fluorometry to simultaneously measure VSD motion and gate closure in N-terminally truncated constructs. We report that mode shifting of the hERG VSD results in a corresponding shift in the voltage-dependent equilibrium of channel closing and that at negative potentials, coupling of the mode-shifted VSD to the gate defines the rate of channel closure. Deletion of the first 25 aa from the N terminus of hERG does not alter mode shifting of the VSD but uncouples the shift from closure of the cytoplasmic gate. Based on these observations, we propose the N-terminal tail as an adaptor that couples voltage sensor return to gate closure to define slow deactivation gating in hERG channels. Furthermore, because the mode shift occurs on a time scale relevant to the cardiac action potential, we suggest a physiological role for this phenomenon in maximizing current flow through hERG channels during repolarization.

  11. A Direct Interaction between the Sigma-1 Receptor and the hERG Voltage-gated K+ Channel Revealed by Atomic Force Microscopy and Homogeneous Time-resolved Fluorescence (HTRF®)*

    PubMed Central

    Balasuriya, Dilshan; D'Sa, Lauren; Talker, Ronel; Dupuis, Elodie; Maurin, Fabrice; Martin, Patrick; Borgese, Franck; Soriani, Olivier; Edwardson, J. Michael

    2014-01-01

    The sigma-1 receptor is an endoplasmic reticulum chaperone protein, widely expressed in central and peripheral tissues, which can translocate to the plasma membrane and modulate the function of various ion channels. The human ether-à-go-go-related gene encodes hERG, a cardiac voltage-gated K+ channel that is abnormally expressed in many human cancers and is known to interact functionally with the sigma-1 receptor. Our aim was to investigate the nature of the interaction between the sigma-1 receptor and hERG. We show that the two proteins can be co-isolated from a detergent extract of stably transfected HEK-293 cells, consistent with a direct interaction between them. Atomic force microscopy imaging of the isolated protein confirmed the direct binding of the sigma-1 receptor to hERG monomers, dimers, and tetramers. hERG dimers and tetramers became both singly and doubly decorated by sigma-1 receptors; however, hERG monomers were only singly decorated. The distribution of angles between pairs of sigma-1 receptors bound to hERG tetramers had two peaks, at ∼90 and ∼180° in a ratio of ∼2:1, indicating that the sigma-1 receptor interacts with hERG with 4-fold symmetry. Homogeneous time-resolved fluorescence (HTRF®) allowed the detection of the interaction between the sigma-1 receptor and hERG within the plane of the plasma membrane. This interaction was resistant to sigma ligands, but was decreased in response to cholesterol depletion of the membrane. We suggest that the sigma-1 receptor may bind to hERG in the endoplasmic reticulum, aiding its assembly and trafficking to the plasma membrane. PMID:25266722

  12. Proline Scan of the hERG Channel S6 Helix Reveals the Location of the Intracellular Pore Gate

    PubMed Central

    Thouta, Samrat; Sokolov, Stanislav; Abe, Yuki; Clark, Sheldon J.; Cheng, Yen M.; Claydon, Tom W.

    2014-01-01

    In Shaker-like channels, the activation gate is formed at the bundle crossing by the convergence of the inner S6 helices near a conserved proline-valine-proline motif, which introduces a kink that allows for electromechanical coupling with voltage sensor motions via the S4-S5 linker. Human ether-a-go-go-related gene (hERG) channels lack the proline-valine-proline motif and the location of the intracellular pore gate and how it is coupled to S4 movement is less clear. Here, we show that proline substitutions within the S6 of hERG perturbed pore gate closure, trapping channels in the open state. Performing a proline scan of the inner S6 helix, from Ile655 to Tyr667 revealed that gate perturbation occurred with proximal (I655P-Q664P), but not distal (R665P-Y667P) substitutions, suggesting that Gln664 marks the position of the intracellular gate in hERG channels. Using voltage-clamp fluorimetry and gating current analysis, we demonstrate that proline substitutions trap the activation gate open by disrupting the coupling between the voltage-sensing unit and the pore of the channel. We characterize voltage sensor movement in one such trapped-open mutant channel and demonstrate the kinetics of what we interpret to be intrinsic hERG voltage sensor movement. PMID:24606930

  13. Statistical analysis of low-energy electron fluxes in the radiation belt: ERG LEP-e measurements

    NASA Astrophysics Data System (ADS)

    Chang, T. F.; Chiang, C. Y.; Tam, S. W. Y.; Syugu, W. J.; Kazama, Y.; Wang, B. J.; Wang, S. Y.; Hori, T.; Yoshizumi, M.; Shinohara, I.

    2017-12-01

    The Exploration of energization and Radiation in Geospace (ERG) satellite, which is led by Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), has observed the Earth's radiation belts for several months. Through years of efforts, Taiwan team successfully delivered the low-energy particle experiments - electron analyzer (LEP-e) for deployment on the ERG satellite. In Taiwan, the project is led by Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in partnership with National Cheng Kung University (NCKU). The LEP-e instrument measures a 3-D velocity distribution function of low energy electrons ranging from 20 eV to 19 keV. We provide an overview of electron fluxes within the radiation belts using the LEP-e instrument data obtained in the past months. The L-shell plots are made upon 100 eV, 1 keV and 10 keV, respectively, to display the electron flux in various L-shells measured by the ERG satellite. The enhancement of the electron fluxes is found to show correspondence with the increase of ring current intensity. These electrons are found to migrate inwards as the ring current increases. We also investigate the 3-D distribution of the electron fluxes and discuss the contribution of the energetic electrons to the ring current.

  14. Rod- versus cone-driven ERGs at different stimulus sizes in normal subjects and retinitis pigmentosa patients.

    PubMed

    Aher, Avinash J; McKeefry, Declan J; Parry, Neil R A; Maguire, John; Murray, I J; Tsai, Tina I; Huchzermeyer, Cord; Kremers, Jan

    2018-02-01

    To study how rod- and cone-driven responses depend on stimulus size in normal subjects and patients with retinitis pigmentosa (RP), and to show that comparisons between responses to full-field (FF) and smaller stimuli can be useful in diagnosing and monitoring disorders of the peripheral retina without the need for lengthy dark adaptation periods. The triple silent substitution technique was used to isolate L-cone-, M-cone- and rod-driven ERGs with 19, 18 and 33% photoreceptor contrasts, respectively, under identical mean luminance conditions. Experiments were conducted on five normal subjects and three RP patients. ERGs on control subjects were recorded at nine different temporal frequencies (between 2 and 60 Hz) for five different stimulus sizes: FF, 70°, 60°, 50° and 40° diameter circular stimuli. Experiments on RP patients involved rod- and L-cone-driven ERG measurements with FF and 40° stimuli at 8 and 48 Hz. Response amplitudes were defined as those of the first harmonic component after Fourier analysis. In normal subjects, rod-driven responses displayed a fundamentally different behavior than cone-driven responses, particularly at low temporal frequencies. At low and intermediate temporal frequencies (≤ 12 Hz), rod-driven signals increased by a factor of about four when measured with smaller stimuli. In contrast, L- and M-cone-driven responses in this frequency region did not change substantially with stimulus size. At high temporal frequencies (≥ 24 Hz), both rod- and cone-driven response amplitudes decreased with decreasing stimulus size. Signals obtained from rod-isolating stimuli under these conditions are likely artefactual. Interestingly, in RP patients, both rod-driven and L-cone-driven ERGs were similar using 40° and FF stimuli. The increased responses with smaller stimuli in normal subjects to rod-isolating stimuli indicate that a fundamentally different mechanism drives the ERGs in comparison with the cone-driven responses. We

  15. Assessment of long-term outcomes associated with urinary prostate cancer antigen 3 and TMPRSS2:ERG gene fusion at repeat biopsy.

    PubMed

    Merdan, Selin; Tomlins, Scott A; Barnett, Christine L; Morgan, Todd M; Montie, James E; Wei, John T; Denton, Brian T

    2015-11-15

    In men with clinically localized prostate cancer who have undergone at least 1 previous negative biopsy and have elevated serum prostate-specific antigen (PSA) levels, long-term health outcomes associated with the assessment of urinary prostate cancer antigen 3 (PCA3) and the transmembrane protease, serine 2 (TMPRSS2):v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG) gene fusion (T2:ERG) have not been investigated previously in relation to the decision to recommend a repeat biopsy. The authors performed a decision analysis using a decision tree for men with elevated PSA levels. The probability of cancer was estimated using the Prostate Cancer Prevention Trial Risk Calculator (version 2.0). The use of PSA alone was compared with the use of PCA3 and T2:ERG scores, with each evaluated independently, in combination with PSA to trigger a repeat biopsy. When PCA3 and T2:ERG score evaluations were used, predefined thresholds were established to determine whether the patient should undergo a repeat biopsy. Biopsy outcomes were defined as either positive (with a Gleason score of <7, 7, or >7) or negative. Probabilities and estimates of 10-year overall survival and 15-year cancer-specific survival were derived from previous studies and a literature review. Outcomes were defined as age-dependent and Gleason score-dependent 10-year overall and 15-year cancer-specific survival rates and the percentage of biopsies avoided. Incorporating the PCA3 score (biopsy threshold, 25; generated based on the urine PCA3 level normalized to the amount of PSA messenger RNA) or the T2:ERG score (biopsy threshold, 10; based on the urine T2:ERG level normalized to the amount of PSA messenger RNA) into the decision to recommend repeat biopsy would have avoided 55.4% or 64.7% of repeat biopsies for the base-case patient, respectively, and changes in the 10-year survival rate were only 0.93% or 1.41%, respectively. Multi-way sensitivity analyses suggested that these results were robust

  16. Highly specific targeting of the TMPRSS2/ERG fusion gene using liposomal nanovectors

    PubMed Central

    Shao, Longjiang; Tekedereli, Ibrahim; Wang, Jianghua; Yuca, Erkan; Tsang, Susan; Sood, Anil; Lopez-Berestein, Gabriel; Ozpolat, Bulent; Ittmann, Michael

    2012-01-01

    Purpose The TMPRSS2/ERG (T/E) fusion gene is present in half of all prostate cancer (PCa) tumors. Fusion of the oncogenic ERG gene with the androgen-regulated TMPRSS2 gene promoter results in expression of fusion mRNAs in PCa cells. The junction of theTMPRSS2 and ERG derived portions of the fusion mRNA constitutes a cancer specific target in cells containing the T/E fusion gene. Targeting the most common alternatively spliced fusion gene mRNA junctional isoforms in vivo using siRNAs in liposomal nanovectors may potentially be a novel, low toxicity treatment for PCa. Experimental Design We designed and optimized siRNAs targeting the two most common T/E fusion gene mRNA junctional isoforms (Type III or Type VI). Specificity of siRNAs was assessed by transient co-transfection in vitro. To test their ability to inhibit growth of PCa cells expressing these fusion gene isoforms in vivo, specific siRNAs in liposomal nanovectors were used to treat mice bearing orthotopic or subcutaneous xenograft tumors expressing the targeted fusion isoforms. Results The targeting siRNAs were both potent and highly specific in vitro. In vivo they significantly inhibited tumor growth. The degree of growth inhibition was variable and was correlated with the extent of fusion gene knockdown. The growth inhibition was associated with marked inhibition of angiogenesis and, to a lesser degree, proliferation and a marked increase in apoptosis of tumor cells. No toxicity was observed. Conclusions Targeting the T/E fusion junction in vivo with specific siRNAs delivered via liposomal nanovectors is a promising therapy for men with PCa. PMID:23052253

  17. Highly specific targeting of the TMPRSS2/ERG fusion gene using liposomal nanovectors.

    PubMed

    Shao, Longjiang; Tekedereli, Ibrahim; Wang, Jianghua; Yuca, Erkan; Tsang, Susan; Sood, Anil; Lopez-Berestein, Gabriel; Ozpolat, Bulent; Ittmann, Michael

    2012-12-15

    The TMPRSS2/ERG (T/E) fusion gene is present in half of all prostate cancer tumors. Fusion of the oncogenic ERG gene with the androgen-regulated TMPRSS2 gene promoter results in expression of fusion mRNAs in prostate cancer cells. The junction of theTMPRSS2- and ERG-derived portions of the fusion mRNA constitutes a cancer-specific target in cells containing the T/E fusion gene. Targeting the most common alternatively spliced fusion gene mRNA junctional isoforms in vivo using siRNAs in liposomal nanovectors may potentially be a novel, low-toxicity treatment for prostate cancer. We designed and optimized siRNAs targeting the two most common T/E fusion gene mRNA junctional isoforms (type III or type VI). Specificity of siRNAs was assessed by transient co-transfection in vitro. To test their ability to inhibit growth of prostate cancer cells expressing these fusion gene isoforms in vivo, specific siRNAs in liposomal nanovectors were used to treat mice bearing orthotopic or subcutaneous xenograft tumors expressing the targeted fusion isoforms. The targeting siRNAs were both potent and highly specific in vitro. In vivo they significantly inhibited tumor growth. The degree of growth inhibition was variable and was correlated with the extent of fusion gene knockdown. The growth inhibition was associated with marked inhibition of angiogenesis and, to a lesser degree, proliferation and a marked increase in apoptosis of tumor cells. No toxicity was observed. Targeting the T/E fusion junction in vivo with specific siRNAs delivered via liposomal nanovectors is a promising therapy for men with prostate cancer. ©2012 AACR.

  18. Overexpression of erg1 gene in Trichoderma harzianum CECT 2413: effect on the induction of tomato defence-related genes.

    PubMed

    Cardoza, R E; Malmierca, M G; Gutiérrez, S

    2014-09-01

    To investigate the effect of the overexpression of erg1 gene of Trichoderma harzianum CECT 2413 (T34) on the Trichoderma-plant interactions and in the biocontrol ability of this fungus. Transformants of T34 strain overexpressing erg1 gene did not show effect on the ergosterol level, although a drastic decrease in the squalene level was observed in the transformants at 96 h of growth. During interaction with plants, the erg1 overexpression resulted in a reduction of the priming ability of several tomato defence-related genes belonging to the salicylate pathway, and also of the TomLoxA gene, which is related to the jasmonate pathway. Interestingly, other jasmonate-related genes, such as PINI and PINII, were slightly induced. The erg1 overexpressed transformants also showed a reduced ability to colonize tomato roots. The ergosterol biosynthetic pathway might play an important role in regulating Trichoderma-plant interactions, although this role does not seem to be restricted to the final product; instead, other intermediates such as squalene, whose role in the Trichoderma-plant interaction has not been characterized, would also play an important role. The functional analysis of genes involved in the synthesis of ergosterol could provide additional strategies to improve the ability of biocontrol of the Trichoderma strains and their interaction with plants. © 2014 The Society for Applied Microbiology.

  19. The role of hERG1 ion channels in epithelial-mesenchymal transition and the capacity of riluzole to reduce cisplatin resistance in colorectal cancer cells.

    PubMed

    Fortunato, Angelo

    2017-08-01

    The transition of cells from the epithelial to the mesenchymal state (EMT) plays an important role in tumor progression. EMT allows cells to acquire mobility, stem-like behavior and resistance to apoptosis and drug treatment. These features turn EMT into a central process in tumor biology. Ion channels are attractive targets for the treatment of cancer since they play critical roles in controlling a wide range of physiological processes that are frequently deregulated in cancer. Here, we investigated the role of ether-a-go-go-related 1 (hERG1) ion channels in the EMT of colorectal cancer cells. We studied the epithelial-mesenchymal profile of different colorectal cancer-derived cell lines and the expression of hERG1 potassium channels in these cell lines using real-time PCR. Next, we knocked down hERG1 expression in HCT116 cells using lentivirus mediated RNA interference and characterized the hERG1 silenced cells in vitro and in vivo. Finally, we investigated the capacity of riluzole, an ion channel-modulating drug used in humans to treat amyotrophic lateral sclerosis, to reduce the resistance of the respective colorectal cancer cells to the chemotherapeutic drug cisplatin. We found that of the colorectal cancer-derived cell lines tested, HCT116 showed the highest mesenchymal profile and a high hERG1 expression. Subsequent hERG1 expression knockdown induced a change in cell morphology, which was accompanied by a reduction in the proliferative and tumorigenic capacities of the cells. Notably, we found that hERG1expression knockdown elicited a reversion of the EMT profile in HCT116 cells with a reacquisition of the epithelial-like profile. We also found that riluzole increased the sensitivity of HCT116 cisplatin-resistant cells to cisplatin. Our data indicate that hERG1 plays a role in the EMT of colorectal cancer cells and that its knockdown reduces the proliferative and tumorigenic capacities of these cells. In addition, we conclude that riluzole may be used in

  20. BDNF improves the efficacy ERG amplitude maintenance by transplantation of retinal stem cells in RCS rats.

    PubMed

    Tian, Chunyu; Weng, Chuan Chuang; Yin, Zheng Qin

    2010-01-01

    The aim of this study was to evaluate the efficacy of subretinal transplantation of rat retinal stem cell when combined with Brain-derived neurotrophic factor (BDNF) in a rat model of retinal degeneration - Royal College of Surgeons (RCS) rats. Retinal stem cells were derived from embryonic day 17 Long-Evans rats and pre-labeled with fluorescence pigment-DiI prior to transplant procedures. RCS rats received injections of retinal stem cells, stem cells+BDNF, phosphate buffered saline or BNDF alone (n = 3 eyes for each procedure). At 1, 2 and 3 months after transplantation, the electroretinogram (ERG) was assessed and the outer nuclear layer thickness measured. The eyes receiving retinal stem cell and stem cell+BDNF transplants showed better photoreceptor maintenance than the other groups (P < 0.01) at all time points. One month after retina transplantation, the amplitudes of rod-ERG and Max-ERG b waves were significantly higher the eyes with stem cells+BDNF (P < 0.01), however, this difference was not seen at two and three months post transplantation. BDNF treatment alone group (without transplanted cells) had no effect when compared to buffer injections. The present results indicate that BDNF can enhance the short-term efficacy of the retinal stem cell transplantation in treating retinal degenerative disease.

  1. Wavelet decomposition analysis in the two-flash multifocal ERG in early glaucoma: a comparison to ganglion cell analysis and visual field.

    PubMed

    Brandao, Livia M; Monhart, Matthias; Schötzau, Andreas; Ledolter, Anna A; Palmowski-Wolfe, Anja M

    2017-08-01

    To further improve analysis of the two-flash multifocal electroretinogram (2F-mfERG) in glaucoma in regard to structure-function analysis, using discrete wavelet transform (DWT) analysis. Sixty subjects [35 controls and 25 primary open-angle glaucoma (POAG)] underwent 2F-mfERG. Responses were analyzed with the DWT. The DWT level that could best separate POAG from controls was compared to the root-mean-square (RMS) calculations previously used in the analysis of the 2F-mfERG. In a subgroup analysis, structure-function correlation was assessed between DWT, optical coherence tomography and automated perimetry (mf103 customized pattern) for the central 15°. Frequency level 4 of the wavelet variance analysis (144 Hz, WVA-144) was most sensitive (p < 0.003). It correlated positively with RMS but had a better AUC. Positive relations were found between visual field, WVA-144 and GCIPL thickness. The highest predictive factor for glaucoma diagnostic was seen in the GCIPL, but this improved further by adding the mean sensitivity and WVA-144. mfERG using WVA analysis improves glaucoma diagnosis, especially when combined with GCIPL and MS.

  2. Celastrol suppresses tumor cell growth through targeting an AR-ERG-NF-κB pathway in TMPRSS2/ERG fusion gene expressing prostate cancer.

    PubMed

    Shao, Longjiang; Zhou, Zhansong; Cai, Yi; Castro, Patricia; Dakhov, Olga; Shi, Ping; Bai, Yaoxia; Ji, Huixiang; Shen, Wenhao; Wang, Jianghua

    2013-01-01

    The TMPRSS2/ERG (T/E) fusion gene is present in the majority of all prostate cancers (PCa). We have shown previously that NF-kB signaling is highly activated in these T/E fusion expressing cells via phosphorylation of NF-kB p65 Ser536 (p536). We therefore hypothesize that targeting NF-kB signaling may be an efficacious approach for the subgroup of PCas that carry T/E fusions. Celastrol is a well known NF-kB inhibitor, and thus may inhibit T/E fusion expressing PCa cell growth. We therefore evaluated Celastrol's effects in vitro and in vivo in VCaP cells, which express the T/E fusion gene. VCaP cells were treated with different concentrations of Celastrol and growth inhibition and target expression were evaluated. To test its ability to inhibit growth in vivo, 0.5 mg/kg Celastrol was used to treat mice bearing subcutaneous VCaP xenograft tumors. Our results show Celastrol can significantly inhibit the growth of T/E fusion expressing PCa cells both in vitro and in vivo through targeting three critical signaling pathways: AR, ERG and NF-kB in these cells. When mice received 0.5 mg/kg Celastrol for 4 times/week, significant growth inhibition was seen with no obvious toxicity or significant weight loss. Therefore, Celastrol is a promising candidate drug for T/E fusion expressing PCa. Our findings provide a novel strategy for the targeted therapy which may benefit the more than half of PCa patients who have T/E fusion expressing PCas.

  3. Identification of Small Molecules Targeting the Posttranscriptional Control of ERG Expression

    DTIC Science & Technology

    2012-10-01

    ied. To establish a cell line expressing lucife rase-ERG fusion protein, the vector along pRL-CMV-Rluc expressing Renilla luciferase gene was...expanded, and examined for the e xpression of t wo different luciferases. A clone expressing both Firefly luciferase and Renilla luciferase was selected...treated with the individual chemical at 10 μM for 24 h. The dual luciferase activities were measured. The ratio of Firefly to Renilla lu ciferase

  4. The Role of ERG and CXCR4 in Prostate Cancer Progression

    DTIC Science & Technology

    2012-06-01

    cells. CXCR4 is a chemokine receptor that has been shown to function as a key receptor for homing of circulating tumor cells to secondary sites...T., Cordon -Cardo, C., Gerald, W., and Pandolfi, P. P. Aberrant ERG expression cooperates with loss of PTEN to promote cancer progression in the...be exon 0, which when included in the fusion is found to be associated with less aggressive behavior and therefore more favorab le prognosis

  5. A functional Kv1.2-hERG chimaeric channel expressed in Pichia pastoris

    PubMed Central

    Dhillon, Mandeep S.; Cockcroft, Christopher J.; Munsey, Tim; Smith, Kathrine J.; Powell, Andrew J.; Carter, Paul; Wrighton, David C.; Rong, Hong-lin; Yusaf, Shahnaz P.; Sivaprasadarao, Asipu

    2014-01-01

    Members of the six-transmembrane segment family of ion channels share a common structural design. However, there are sequence differences between the members that confer distinct biophysical properties on individual channels. Currently, we do not have 3D structures for all members of the family to help explain the molecular basis for the differences in their biophysical properties and pharmacology. This is due to low-level expression of many members in native or heterologous systems. One exception is rat Kv1.2 which has been overexpressed in Pichia pastoris and crystallised. Here, we tested chimaeras of rat Kv1.2 with the hERG channel for function in Xenopus oocytes and for overexpression in Pichia. Chimaera containing the S1–S6 transmembrane region of HERG showed functional and pharmacological properties similar to hERG and could be overexpressed and purified from Pichia. Our results demonstrate that rat Kv1.2 could serve as a surrogate to express difficult-to-overexpress members of the six-transmembrane segment channel family. PMID:24569544

  6. Peptide Immunization Against ERG and Immunogenic Mutations to Treat Prostate Cancer

    DTIC Science & Technology

    2014-09-01

    or erg295 (QlWQFllel) were produced by the nIH tetramer facility at emory Uni- versity (atlanta, ga ). Splenocytes from HHD mice were stained with... 350 –358. 39. Bijker MS, van den Eeden SJ, Franken KL, Melief CJ, Offringa R, et al. (2007) CD8+ CTL priming by exact peptide epitopes in incomplete...Medicine, Atlanta, GA . 3 Department of Medicine, Renal Division, Brigham and Women’s Hospital, and Harvard Medical School, Boston, MA Running

  7. The Role of ERG and CXCR4 in Prostate Cancer Progression

    DTIC Science & Technology

    2010-06-01

    Attard, G., Clark, J., Ambroisine, L., Fisher, G., Kovacs, G., Flohr, P., Berney , D., Foster, C. S., Fletcher, A., Gerald, W. L., Moller, H., Reuter...Parker, M. D., Foster, C. S., Berney , D., Kovacs, G., and Cooper, C. S. Complex patterns of ETS gene alteration arise during cancer development in...Kovacs G, Flohr P, Berney D, Foster CS, Fletcher A, Gerald WL, et al. (2008). Duplication of the fusion of TMPRSS2 to ERG sequences identifies fatal

  8. Validation and Clinical Utility of the hERG IC50:Cmax Ratio to Determine the Risk of Drug-Induced Torsades de Pointes: A Meta-Analysis.

    PubMed

    Lehmann, David F; Eggleston, William D; Wang, Dongliang

    2018-03-01

    Use of the QT interval corrected for heart rate (QTc) on the electrocardiogram (ECG) to predict torsades de pointes (TdP) risk from culprit drugs is neither sensitive nor specific. The ratio of the half-maximum inhibitory concentration of the hERG channel (hERG IC50) to the peak serum concentration of unbound drug (C max ) is used during drug development to screen out chemical entities likely to cause TdP. To validate the use of the hERG IC50:C max ratio to predict TdP risk from a culprit drug by its correlation with TdP incidence. Medline (between 1966 and March 2017) was accessed for hERG IC50 and C max values from the antihistamine, fluoroquinolone, and antipsychotic classes to identify cases of drug-induced TdP. Exposure to a culprit drug was estimated from annual revenues reported by the manufacturer. Inclusion criteria for TdP cases were provision of an ECG tracing that demonstrated QTc prolongation with TdP and normal serum values of potassium, calcium, and magnesium. Cases reported in patients with a prior rhythm disturbance and those involving a drug interaction were excluded. The Meta-Analysis of Observational Studies in Epidemiology checklist was used for epidemiological data extraction by two authors. Negligible risk drugs were defined by an hERG IC50:C max ratio that correlated with less than a 5% chance of one TdP event for every 100 million exposures (relative risk [RR] 1.0). The hERG IC50:C max ratio correlated with TdP risk (0.312; 95% confidence interval 0.205-0.476, p<0.0001), a ratio of 80 (RR 1.0). The RR from olanzapine is on par with loratadine; ziprasidone is comparable with ciprofloxacin. Drugs with an RR greater than 50 include astemizole, risperidone, haloperidol, and thioridazine. The hERG IC50:C max ratio was correlated with TdP incidence for culprit drugs. This validation provides support for the potential use of the hERG IC50:C max ratio for clinical decision making in instances of drug selection where TdP risk is a concern. © 2018

  9. Development and Comparison of hERG Blocker Classifiers: Assessment on Different Datasets Yields Markedly Different Results.

    PubMed

    Marchese Robinson, Richard L; Glen, Robert C; Mitchell, John B O

    2011-05-16

    In recent years, considerable effort has been invested in the development of classification models for prospective hERG inhibitors, due to the implications of hERG blockade for cardiotoxicity and the low throughput of functional hERG assays. We present novel approaches for binary classification which seek to separate strong inhibitors (IC50 <1 µM) from 'non-blockers' exhibiting moderate (1-10 µM) or weak (IC50 ≥10 µM) inhibition, as required by the pharmaceutical industry. Our approaches are based on (discretized) 2D descriptors, selected using Winnow, with additional models generated using Random Forest (RF) and Support Vector Machines (SVMs). We compare our models to those previously developed by Thai and Ecker and by Dubus et al. The purpose of this paper is twofold: 1. To propose that our approaches (with Matthews Correlation Coefficients from 0.40 to 0.87 on truly external test sets, when extrapolation beyond the applicability domain was not evident and sufficient quantities of data were available for training) are competitive with those currently proposed in the literature. 2. To highlight key issues associated with building and assessing truly predictive models, in particular the considerable variation in model performance when training and testing on different datasets. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Application of empirical Bayes methods to predict the rate of decline in ERG at the individual level among patients with retinitis pigmentosa.

    PubMed

    Qiu, Weiliang; Sandberg, Michael A; Rosner, Bernard

    2018-05-31

    Retinitis pigmentosa is one of the most common forms of inherited retinal degeneration. The electroretinogram (ERG) can be used to determine the severity of retinitis pigmentosa-the lower the ERG amplitude, the more severe the disease is. In practice for career, lifestyle, and treatment counseling, it is of interest to predict the ERG amplitude of a patient at a future time. One approach is prediction based on the average rate of decline for individual patients. However, there is considerable variation both in initial amplitude and in rate of decline. In this article, we propose an empirical Bayes (EB) approach to incorporate the variations in initial amplitude and rate of decline for the prediction of ERG amplitude at the individual level. We applied the EB method to a collection of ERGs from 898 patients with 3 or more visits over 5 or more years of follow-up tested in the Berman-Gund Laboratory and observed that the predicted values at the last (kth) visit obtained by using the proposed method based on data for the first k-1 visits are highly correlated with the observed values at the kth visit (Spearman correlation =0.93) and have a higher correlation with the observed values than those obtained based on either the population average decline rate or those obtained based on the individual decline rate. The mean square errors for predicted values obtained by the EB method are also smaller than those predicted by the other methods. Copyright © 2018 John Wiley & Sons, Ltd.

  11. Interactions between voltage sensor and pore domains in a hERG K+ channel model from molecular simulations and the effects of a voltage sensor mutation.

    PubMed

    Colenso, Charlotte K; Sessions, Richard B; Zhang, Yi H; Hancox, Jules C; Dempsey, Christopher E

    2013-06-24

    The hERG K(+) channel is important for establishing normal electrical activity in the human heart. The channel's unique gating response to membrane potential changes indicates specific interactions between voltage sensor and pore domains that are poorly understood. In the absence of a crystal structure we constructed a homology model of the full hERG membrane domain and performed 0.5 μs molecular dynamics (MD) simulations in a hydrated membrane. The simulations identify potential interactions involving residues at the extracellular surface of S1 in the voltage sensor and at the N-terminal end of the pore helix in the hERG model. In addition, a diffuse interface involving hydrophobic residues on S4 (voltage sensor) and pore domain S5 of an adjacent subunit was stable during 0.5 μs of simulation. To assess the ability of the model to give insight into the effects of channel mutation we simulated a hERG mutant that contains a Leu to Pro substitution in the voltage sensor S4 helical segment (hERG L532P). Consistent with the retention of gated K(+) conductance, the L532P mutation was accommodated in the S4 helix with little disruption of helical structure. The mutation reduced the extent of interaction across the S4-S5 interface, suggesting a structural basis for the greatly enhanced deactivation rate in hERG L532P. The study indicates that pairwise comparison of wild-type and mutated channel models is a useful approach to interpreting functional data where uncertainty in model structures exist.

  12. Pharmacological and electrophysiological characterization of nine, single nucleotide polymorphisms of the hERG-encoded potassium channel

    PubMed Central

    Männikkö, R; Overend, G; Perrey, C; Gavaghan, CL; Valentin, J-P; Morten, J; Armstrong, M; Pollard, CE

    2010-01-01

    Background and purpose: Potencies of compounds blocking KV11.1 [human ether-ago-go-related gene (hERG)] are commonly assessed using cell lines expressing the Caucasian wild-type (WT) variant. Here we tested whether such potencies would be different for hERG single nucleotide polymorphisms (SNPs). Experimental approach: SNPs (R176W, R181Q, Del187-189, P347S, K897T, A915V, P917L, R1047L, A1116V) and a binding-site mutant (Y652A) were expressed in Tet-On CHO-K1 cells. Potencies [mean IC50; lower/upper 95% confidence limit (CL)] of 48 hERG blockers was estimated by automated electrophysiology [IonWorks™ HT (IW)]. In phase one, rapid potency comparison of each WT-SNP combination was made for each compound. In phase two, any compound-SNP combinations from phase one where the WT upper/lower CL did not overlap with those of the SNPs were re-examined. Electrophysiological WT and SNP parameters were determined using conventional electrophysiology. Key results: IW detected the expected sixfold potency decrease for propafenone in Y652A. In phase one, the WT lower/upper CL did not overlap with those of the SNPs for 77 compound-SNP combinations. In phase two, 62/77 cases no longer yielded IC50 values with non-overlapping CLs. For seven of the remaining 15 cases, there were non-overlapping CLs but in the opposite direction. For the eight compound-SNP combinations with non-overlapping CLs in the same direction as for phase 1, potencies were never more than twofold apart. The only statistically significant electrophysiological difference was the voltage dependence of activation of R1047L. Conclusion and implications: Potencies of hERG channel blockers defined using the Caucasian WT sequence, in this in vitro assay, were representative of potencies for common SNPs. This article is part of a themed section on QT safety. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2010 PMID:19673885

  13. The effects of hypoxia on the ERG in paediatric cerebral malaria.

    PubMed

    Lochhead, J; Movaffaghy, A; Falsini, B; Harding, S; Riva, C; Molyneux, M

    2010-02-01

    Cerebral malaria (CM) is a disease of high mortality worldwide. It can be associated with malarial retinopathy (MR) resulting from impaired perfusion within the retinal microvasculature. Areas of capillary non-perfusion (CNP) appear white (retinal whitening) on ophthalmoloscopy. In this study, electrophysiological investigations were performed to investigate the physiological consequences of these hypoxic and ischaemic changes. Children admitted with CM were assessed for inclusion in the study. Those with MR underwent further detailed fundus assessment to quantify retinal whitening and were then designated a severity score. Electrophysiological recordings were performed using a miniganzfeldt stimulator with calibration to the International Society for Clinical Electrophysiology of Visual (ISCEV) standards. ERG data were then analysed with respect to presence of MR and also graded disease severity. Thirty-one children were recruited with a diagnosis of CM, 20 had MR (group 1), and 11 had absent MR (group 2). Statistical analyses of these two groups showed a significant relationship between reduced single flash cone b wave amplitude (CBWA) and increased severity of retinal whitening/CNP (P<0.05). Cone and maximal response b : a wave ratios remained >1 in all subjects. Retinal whitening/CNP in MR is associated with significant changes in ERG cone b wave function. The relatively high b : a ratio is compatible with the high frequency of MR resolution without sequelae.

  14. Prognostic relevance of proliferation markers (Ki-67, PHH3) within the cross-relation of ERG translocation and androgen receptor expression in prostate cancer.

    PubMed

    Goltz, Diane; Montani, Matteo; Braun, Martin; Perner, Sven; Wernert, Nicolas; Jung, Klaus; Dietel, Manfred; Stephan, Carsten; Kristiansen, Glen

    2015-12-01

    We evaluated the prognostic value of the mitosis-associated marker phosphorylated histone H3 (PHH3) and Ki-67 in prostate cancer with respect to ERG status and androgen receptor (AR) expression.PHH3 and Ki-67 expression was immunohistochemically detected and digitally quantitated in a radical prostatectomy cohort (n = 640). The results were correlated to clinicopathological parameters including biochemical recurrence times. Prognostic values of PHH3 and Ki-67 were analysed by Cox regression and Kaplan-Meier statistics.In prostate cancer, mean Ki-67 and PHH3 rates were 3.40% (95%CI 3.16-3.63%) and 0.0152% (95%CI 0.0112-0.0191%), respectively.Ki-67 showed a significant correlation with Gleason scores, pT status, margin status, and AR expression, while PHH3 showed a significant correlation with Gleason scores and pT status. Univariate analyses for biochemical recurrence times demonstrated a significant prognostic value for median Ki-67 rate and for the PHH3 rate of the 90th percentile. Of importance, in patient subgroups stratified according to AR expression and ERG translocation, the prognostic power of proliferation markers PHH3 and Ki-67 was markedly enhanced in ERG translocation negative and high-level AR expressing ERG translocation positive prostate cancers.As expected, the proliferation markers PHH3 and Ki-67 predict adverse outcome of prostate cancer and have a particularly pronounced prognostic value in specific molecular subsets of prostate cancer (ERG- or AR+).

  15. Performance of Machine Learning Algorithms for Qualitative and Quantitative Prediction Drug Blockade of hERG1 channel.

    PubMed

    Wacker, Soren; Noskov, Sergei Yu

    2018-05-01

    Drug-induced abnormal heart rhythm known as Torsades de Pointes (TdP) is a potential lethal ventricular tachycardia found in many patients. Even newly released anti-arrhythmic drugs, like ivabradine with HCN channel as a primary target, block the hERG potassium current in overlapping concentration interval. Promiscuous drug block to hERG channel may potentially lead to perturbation of the action potential duration (APD) and TdP, especially when with combined with polypharmacy and/or electrolyte disturbances. The example of novel anti-arrhythmic ivabradine illustrates clinically important and ongoing deficit in drug design and warrants for better screening methods. There is an urgent need to develop new approaches for rapid and accurate assessment of how drugs with complex interactions and multiple subcellular targets can predispose or protect from drug-induced TdP. One of the unexpected outcomes of compulsory hERG screening implemented in USA and European Union resulted in large datasets of IC 50 values for various molecules entering the market. The abundant data allows now to construct predictive machine-learning (ML) models. Novel ML algorithms and techniques promise better accuracy in determining IC 50 values of hERG blockade that is comparable or surpassing that of the earlier QSAR or molecular modeling technique. To test the performance of modern ML techniques, we have developed a computational platform integrating various workflows for quantitative structure activity relationship (QSAR) models using data from the ChEMBL database. To establish predictive powers of ML-based algorithms we computed IC 50 values for large dataset of molecules and compared it to automated patch clamp system for a large dataset of hERG blocking and non-blocking drugs, an industry gold standard in studies of cardiotoxicity. The optimal protocol with high sensitivity and predictive power is based on the novel eXtreme gradient boosting (XGBoost) algorithm. The ML-platform with XGBoost

  16. Evaluating the Efficacy of ERG Targeted Therapy in vivo for Prostate Tumors

    DTIC Science & Technology

    2016-06-01

    we used may have undergone silencing which is a well characterized phenomenon in transgenic mice.  Re-initiated breeding for novel bitransgenic...a target for prostate cancer therapy by using novel transgenic mice. As many as 50% of prostate cancers possess a chromosomal translocation... breeding of more mice using a different tetO-ERG founder line and are in the midst of processing samples for analysis. Despite these setbacks

  17. Predicting QT prolongation in humans during early drug development using hERG inhibition and an anaesthetized guinea-pig model

    PubMed Central

    Yao, X; Anderson, D L; Ross, S A; Lang, D G; Desai, B Z; Cooper, D C; Wheelan, P; McIntyre, M S; Bergquist, M L; MacKenzie, K I; Becherer, J D; Hashim, M A

    2008-01-01

    Background and purpose: Drug-induced prolongation of the QT interval can lead to torsade de pointes, a life-threatening ventricular arrhythmia. Finding appropriate assays from among the plethora of options available to predict reliably this serious adverse effect in humans remains a challenging issue for the discovery and development of drugs. The purpose of the present study was to develop and verify a reliable and relatively simple approach for assessing, during preclinical development, the propensity of drugs to prolong the QT interval in humans. Experimental approach: Sixteen marketed drugs from various pharmacological classes with a known incidence—or lack thereof—of QT prolongation in humans were examined in hERG (human ether a-go-go-related gene) patch-clamp assay and an anaesthetized guinea-pig assay for QT prolongation using specific protocols. Drug concentrations in perfusates from hERG assays and plasma samples from guinea-pigs were determined using liquid chromatography-mass spectrometry. Key results: Various pharmacological agents that inhibit hERG currents prolong the QT interval in anaesthetized guinea-pigs in a manner similar to that seen in humans and at comparable drug exposures. Several compounds not associated with QT prolongation in humans failed to prolong the QT interval in this model. Conclusions and implications: Analysis of hERG inhibitory potency in conjunction with drug exposures and QT interval measurements in anaesthetized guinea-pigs can reliably predict, during preclinical drug development, the risk of human QT prolongation. A strategy is proposed for mitigating the risk of QT prolongation of new chemical entities during early lead optimization. PMID:18587422

  18. ``High energy Electron exPeriment (HEP)'' onboard the ERG satellite

    NASA Astrophysics Data System (ADS)

    Mitani, T.; Takashima, T.; Kasahara, S.; Miyake, W.; Hirahara, M.

    2017-12-01

    The Exploration of energization and Radiation in Geospace (ERG) satellite was successfully launched on December 20, 2016, and now explores how relativistic electrons in the radiation belts are generated during space storms. "High energy Electron exPeriment (HEP)" onboard the ERG satellite observes 70 keV - 2 MeV electrons and provides three-dimensional velocity distribution of electrons every spacecraft spin period. Electrons are observed by two types of camera designs, HEP-L and HEP-H, with regard to geometrical factor and energy range. HEP-L observes 0.1 - 1 MeV electrons and its geometrical factor (G-factor) is 10-3 cm2 str, and HEP-H observes 0.7 - 2 MeV and G-factor is 10-2 cm2 str. HEP-L and HEP-H each consist of three pin-hole type cameras, and each camera consist of mechanical collimator, stacked silicon semiconductor detectors and readout ASICs. HEP-H has larger opening angle of the collimator and more silicon detectors to observe higher energy electrons than HEP-L. The initial checkout in orbit was carried out in February 2017 and it was confirmed that there was no performance degradation by comparing the results of the initial checkout in orbit and the prelaunch function tests. Since late March, HEP has carried out normal observation. HEP observed losses and recovery of the outer radiation belt electrons several times up to now. In this presentation we introduce the HEP instrument design, prelaunch tests results and report the initial results in orbit.

  19. Facultative Sterol Uptake in an Ergosterol-Deficient Clinical Isolate of Candida glabrata Harboring a Missense Mutation in ERG11 and Exhibiting Cross-Resistance to Azoles and Amphotericin B

    PubMed Central

    Hull, Claire M.; Parker, Josie E.; Bader, Oliver; Weig, Michael; Gross, Uwe; Warrilow, Andrew G. S.; Kelly, Diane E.

    2012-01-01

    We identified a clinical isolate of Candida glabrata (CG156) exhibiting flocculent growth and cross-resistance to fluconazole (FLC), voriconazole (VRC), and amphotericin B (AMB), with MICs of >256, >256, and 32 μg ml−1, respectively. Sterol analysis using gas chromatography-mass spectrometry (GC-MS) revealed that CG156 was a sterol 14α-demethylase (Erg11p) mutant, wherein 14α-methylated intermediates (lanosterol was >80% of the total) were the only detectable sterols. ERG11 sequencing indicated that CG156 harbored a single-amino-acid substitution (G315D) which nullified the function of native Erg11p. In heterologous expression studies using a doxycycline-regulatable Saccharomyces cerevisiae erg11 strain, wild-type C. glabrata Erg11p fully complemented the function of S. cerevisiae sterol 14α-demethylase, restoring growth and ergosterol synthesis in recombinant yeast; mutated CG156 Erg11p did not. CG156 was culturable using sterol-free, glucose-containing yeast minimal medium (glcYM). However, when grown on sterol-supplemented glcYM (with ergosta 7,22-dienol, ergosterol, cholestanol, cholesterol, Δ7-cholestenol, or desmosterol), CG156 cultures exhibited shorter lag phases, reached higher cell densities, and showed alterations in cellular sterol composition. Unlike comparator isolates (harboring wild-type ERG11) that became less sensitive to FLC and VRC when cultured on sterol-supplemented glcYM, facultative sterol uptake by CG156 did not affect its azole-resistant phenotype. Conversely, CG156 grown using glcYM with ergosterol (or with ergosta 7,22-dienol) showed increased sensitivity to AMB; CG156 grown using glcYM with cholesterol (or with cholestanol) became more resistant (MICs of 2 and >64 μg AMB ml−1, respectively). Our results provide insights into the consequences of sterol uptake and metabolism on growth and antifungal resistance in C. glabrata. PMID:22615281

  20. The human ether-a-go-go-related gene (hERG) current inhibition selectively prolongs action potential of midmyocardial cells to augment transmural dispersion.

    PubMed

    Yasuda, C; Yasuda, S; Yamashita, H; Okada, J; Hisada, T; Sugiura, S

    2015-08-01

    The majority of drug induced arrhythmias are related to the prolongation of action potential duration following inhibition of rapidly activating delayed rectifier potassium current (I(Kr)) mediated by the hERG channel. However, for arrhythmias to develop and be sustained, not only the prolongation of action potential duration but also its transmural dispersion are required. Herein, we evaluated the effect of hERG inhibition on transmural dispersion of action potential duration using the action potential clamp technique that combined an in silico myocyte model with the actual I(Kr) measurement. Whole cell I(Kr) current was measured in Chinese hamster ovary cells stably expressing the hERG channel. The measured current was coupled with models of ventricular endocardial, M-, and epicardial cells to calculate the action potentials. Action potentials were evaluated under control condition and in the presence of 1, 10, or 100 μM disopyramide, an hERG inhibitor. Disopyramide dose-dependently increased the action potential durations of the three cell types. However, action potential duration of M-cells increased disproportionately at higher doses, and was significantly different from that of epicardial and endocardial cells (dispersion of repolarization). By contrast, the effects of disopyramide on peak I(Kr) and instantaneous current-voltage relation were similar in all cell types. Simulation study suggested that the reduced repolarization reserve of M-cell with smaller amount of slowly activating delayed rectifier potassium current levels off at longer action potential duration to make such differences. The action potential clamp technique is useful for studying the mechanism of arrhythmogenesis by hERG inhibition through the transmural dispersion of repolarization.

  1. The Study of the plasmaspheric refilling using the data from the ERG, the VAPs, the ground-based magnetometers and the IPE model

    NASA Astrophysics Data System (ADS)

    Obana, Y.; Maruyama, N.; Masahito, N.; Matsuoka, A.; Teramoto, M.; Nomura, R.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Kasahara, Y.; Matsuda, S.; Kumamoto, A.; Tsuchiya, F.; Yoshizumi, M.; Shinohara, I.

    2017-12-01

    Earth's inner magnetosphere is a complex dynamical region of geo space comprising plasma populations with wide energy ranges, the plasmasphere, ring current, and radiation belts. They form a closely coupled system, thus, the plasmasphere is the lowest energy population in the inner magnetosphere, but the accurate prediction of the evolution of the plasmasphere is critical in understanding the dynamics of the inner magnetosphere, which include even the highest energy population, the radiation belts. In this study, we study plasmaspheric refilling following geomagnetic storms using data from ERG-MGF, ERG-PWE, RBSP-EMFISIS and Ground-based magneto­meters. DC magnetic field data measured by ERG-MGF, RBSP-EMFISIS and ground-based magnetometers provides the frequency of the toroidal mode field line resonances. From this information, the equatorial plasma mass density is estimated by solving the MHD wave equation for suitable models of the magnetic field and the field line density distribution. ERG-PWE and RBSP-EMFISIS provide measurements of wave electric and magnetic field, thus we can estimate the local electron density from the plasma wave spectrograms by identifying narrow-band emission at the upper-hybrid resonance frequency. Furthermore, using Ionosphere Plasmasphere Electrodynamics Model (IPE), we calculate the plasmaspheric refilling rates and evaluate the relative contribution of various mechanisms (heating, neutral particle density, composition and wings, etc.) to the refilling rate.

  2. Analysis of the ergosterol biosynthesis pathway cloning, molecular characterization and phylogeny of lanosterol 14 α-demethylase (ERG11) gene of Moniliophthora perniciosa.

    PubMed

    de Oliveira Ceita, Geruza; Vilas-Boas, Laurival Antônio; Castilho, Marcelo Santos; Carazzolle, Marcelo Falsarella; Pirovani, Carlos Priminho; Selbach-Schnadelbach, Alessandra; Gramacho, Karina Peres; Ramos, Pablo Ivan Pereira; Barbosa, Luciana Veiga; Pereira, Gonçalo Amarante Guimarães; Góes-Neto, Aristóteles

    2014-10-01

    The phytopathogenic fungus Moniliophthora perniciosa (Stahel) Aime & Philips-Mora, causal agent of witches' broom disease of cocoa, causes countless damage to cocoa production in Brazil. Molecular studies have attempted to identify genes that play important roles in fungal survival and virulence. In this study, sequences deposited in the M. perniciosa Genome Sequencing Project database were analyzed to identify potential biological targets. For the first time, the ergosterol biosynthetic pathway in M. perniciosa was studied and the lanosterol 14α-demethylase gene (ERG11) that encodes the main enzyme of this pathway and is a target for fungicides was cloned, characterized molecularly and its phylogeny analyzed. ERG11 genomic DNA and cDNA were characterized and sequence analysis of the ERG11 protein identified highly conserved domains typical of this enzyme, such as SRS1, SRS4, EXXR and the heme-binding region (HBR). Comparison of the protein sequences and phylogenetic analysis revealed that the M. perniciosa enzyme was most closely related to that of Coprinopsis cinerea.

  3. Structural refinement of the hERG1 pore and voltage-sensing domains with ROSETTA-membrane and molecular dynamics simulations.

    PubMed

    Subbotina, Julia; Yarov-Yarovoy, Vladimir; Lees-Miller, James; Durdagi, Serdar; Guo, Jiqing; Duff, Henry J; Noskov, Sergei Yu

    2010-11-01

    The hERG1 gene (Kv11.1) encodes a voltage-gated potassium channel. Mutations in this gene lead to one form of the Long QT Syndrome (LQTS) in humans. Promiscuous binding of drugs to hERG1 is known to alter the structure/function of the channel leading to an acquired form of the LQTS. Expectably, creation and validation of reliable 3D model of the channel have been a key target in molecular cardiology and pharmacology for the last decade. Although many models were built, they all were limited to pore domain. In this work, a full model of the hERG1 channel is developed which includes all transmembrane segments. We tested a template-driven de-novo design with ROSETTA-membrane modeling using side-chain placements optimized by subsequent molecular dynamics (MD) simulations. Although backbone templates for the homology modeled parts of the pore and voltage sensors were based on the available structures of KvAP, Kv1.2 and Kv1.2-Kv2.1 chimera channels, the missing parts are modeled de-novo. The impact of several alignments on the structure of the S4 helix in the voltage-sensing domain was also tested. Herein, final models are evaluated for consistency to the reported structural elements discovered mainly on the basis of mutagenesis and electrophysiology. These structural elements include salt bridges and close contacts in the voltage-sensor domain; and the topology of the extracellular S5-pore linker compared with that established by toxin foot-printing and nuclear magnetic resonance studies. Implications of the refined hERG1 model to binding of blockers and channels activators (potent new ligands for channel activations) are discussed. © 2010 Wiley-Liss, Inc.

  4. Computational Modeling Reveals Key Contributions of KCNQ and hERG Currents to the Malleability of Uterine Action Potentials Underpinning Labor

    PubMed Central

    Tong, Wing-Chiu; Tribe, Rachel M.; Smith, Roger; Taggart, Michael J.

    2014-01-01

    The electrical excitability of uterine smooth muscle cells is a key determinant of the contraction of the organ during labor and is manifested by spontaneous, periodic action potentials (APs). Near the end of term, APs vary in shape and size reflecting an ability to change the frequency, duration and amplitude of uterine contractions. A recent mathematical model quantified several ionic features of the electrical excitability in uterine smooth muscle cells. It replicated many of the experimentally recorded uterine AP configurations but its limitations were evident when trying to simulate the long-duration bursting APs characteristic of labor. A computational parameter search suggested that delayed rectifying K+ currents could be a key model component requiring improvement to produce the longer-lasting bursting APs. Of the delayed rectifying K+ currents family it is of interest that KCNQ and hERG channels have been reported to be gestationally regulated in the uterus. These currents exhibit features similar to the broadly defined uterine I K1 of the original mathematical model. We thus formulated new quantitative descriptions for several I KCNQ and I hERG. Incorporation of these currents into the uterine cell model enabled simulations of the long-lasting bursting APs. Moreover, we used this modified model to simulate the effects of different contributions of I KCNQ and I hERG on AP form. Our findings suggest that the alterations in expression of hERG and KCNQ channels can potentially provide a mechanism for fine tuning of AP forms that lends a malleability for changing between plateau-like and long-lasting bursting-type APs as uterine cells prepare for parturition. PMID:25474527

  5. Ivabradine prolongs phase 3 of cardiac repolarization and blocks the hERG1 (KCNH2) current over a concentration-range overlapping with that required to block HCN4.

    PubMed

    Lees-Miller, James P; Guo, Jiqing; Wang, Yibo; Perissinotti, Laura L; Noskov, Sergei Y; Duff, Henry J

    2015-08-01

    In Europe, ivabradine has recently been approved to treat patients with angina who have intolerance to beta blockers and/or heart failure. Ivabradine is considered to act specifically on the sinoatrial node by inhibiting the If current (the funny current) to slow automaticity. However, in vitro studies show that ivabradine prolongs phase 3 repolarization in ventricular tissue. No episodes of Torsades de Pointes have been reported in randomized clinical studies. The objective of this study is to assess whether ivabradine blocked the hERG1 current. In the present study we discovered that ivabradine prolongs action potential and blocks the hERG current over a range of concentrations overlapping with those required to block HCN4. Ivabradine produced tonic, rather than use-dependent block. The mutation Y652A significantly suppressed pharmacologic block of hERG by ivabradine. Disruption of C-type inactivation also suppressed block of hERG1 by ivabradine. Molecular docking and molecular dynamics simulations indicate that ivabradine may access the inner cavity of the hERG1 via a lipophilic route and has a well-defined binding site in the closed state of the channel. Structural organization of the binding pockets for ivabradine is discussed. Ivabradine blocks hERG and prolongs action potential duration. Our study is potentially important because it indicates the need for active post marketing surveillance of ivabradine. Importantly, proarrhythmia of a number of other drugs has only been discovered during post marketing surveillance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Enhanced oxidative killing of azole-resistant Candida glabrata strains with ERG11 deletion.

    PubMed Central

    Kan, V L; Geber, A; Bennett, J E

    1996-01-01

    The susceptibility of genetically defined Candida glabrata strains to killing by H2O2 and neutrophils was assessed. Fluconazole-susceptible L5L and L5D strains demonstrated survival rates higher than those of two fluconazole-resistant strains lacking the ERG11 gene coding for 14 alpha-demethylase. Fluconazole resistance can occur by mechanisms which increase fungal susceptibility to oxidative killing by H2O2 and neutrophils. PMID:8807069

  7. Clonal Evaluation of Prostate Cancer by ERG/SPINK1 Status to Improve Prognosis Prediction

    DTIC Science & Technology

    2017-12-01

    meaning that most men with prostate cancer have multiple, genetically distinct cancers. Pathologists cannot assess clonality by routine microscopic...Hence, in this proposal we utilized dual ERG/SPINK1 immunohistochemistry (IHC)—as a readout of clonal, mutually exclusive molecular subtypes—to assess...multiclonal (also referred to as multifocal), meaning that more than 80% of men with prostate cancer actually have multiple, genetically distinct

  8. Age-related change in fast adaptation mechanisms measured with the scotopic full-field ERG.

    PubMed

    Tillman, Megan A; Panorgias, Athanasios; Werner, John S

    2016-06-01

    To quantify the response dynamics of fast adaptation mechanisms of the scotopic ERG in younger and older adults using full-field m-sequence flash stimulation. Scotopic ERGs were measured for a series of flashes separated by 65 ms over a range of 260 ms in 16 younger (20-26, 22.2 ± 2.1; range mean ±1 SD) and 16 older (65-85, 71.2 ± 7) observers without retinal pathology. A short-wavelength (λ peak = 442 nm) LED was used for scotopic stimulation, and the flashes ranged from 0.0001 to 0.01 cd s m(-2). The complete binary kernel series was derived from the responses to the m-sequence flash stimulation, and the first- and second-order kernel responses were analyzed. The first-order kernel represented the response to a single, isolated flash, while the second-order kernels reflected the adapted flash responses that followed a single flash by one or more base intervals. B-wave amplitudes of the adapted flash responses were measured and plotted as a function of interstimulus interval to describe the recovery of the scotopic ERG. A linear function was fitted to the linear portion of the recovery curve, and the slope of the line was used to estimate the rate of fast adaptation recovery. The amplitudes of the isolated flash responses and rates of scotopic fast adaptation recovery were compared between the younger and older participants using a two-way ANOVA. The isolated flash responses and rates of recovery were found to be significantly lower in the older adults. However, there was no difference between the two age groups in response amplitude or recovery rate after correcting for age-related changes in the density of the ocular media. These results demonstrated that the rate of scotopic fast adaptation recovery of normal younger and older adults is similar when stimuli are equated for retinal illuminance.

  9. Onboard Processing on PWE OFA/WFC (Onboard Frequency Analyzer/Waveform Capture) aboard the ERG (ARASE) Satellite

    NASA Astrophysics Data System (ADS)

    Matsuda, S.; Kasahara, Y.; Kojima, H.; Kasaba, Y.; Yagitani, S.; Ozaki, M.; Imachi, T.; Ishisaka, K.; Kurita, S.; Ota, M.; Kumamoto, A.; Tsuchiya, F.; Yoshizumi, M.; Matsuoka, A.; Teramoto, M.; Shinohara, I.

    2017-12-01

    Exploration of energization and Radiation in Geospace (ERG) is a mission for understanding particle acceleration, loss mechanisms, and the dynamic evolution of space storms in the context of cross-energy and cross-regional coupling [Miyoshi et al., 2012]. The ERG (ARASE) satellite was launched on December 20, 2016, and successfully inserted into an orbit. The Plasma Wave Experiment (PWE) is one of the science instruments on board the ERG satellite to measure electric field and magnetic field in the inner magnetosphere. PWE consists of three sub-components, EFD (Electric Field Detector), OFA/WFC (Onboard Frequency Analyzer and Waveform Capture), and HFA (High Frequency Analyzer). Especially, OFA/WFC measures electric and magnetic field spectrum and waveform from a few Hz to 20 kHz. OFA/WFC processes signals detected by a couple of dipole wire-probe antenna (WPT) and tri-axis magnetic search coils (MSC) installed onboard the satellite. The PWE-OFA subsystem calculates and produces three kind of data; OFA-SPEC (power spectrum), OFA-MATRIX (spectrum matrix), and OFA-COMPLEX (complex spectrum). They are continuously processed 24 hours per day and all data are sent to the ground. OFA-MATRIX and OFA-COMPLEX are used for polarization analyses and direction finding of the plasma waves. The PWE-WFC subsystem measures raw (64 kHz sampled) and down-sampled (1 kHz sampled) burst waveform detected by the WPT and the MSC sensors. It activates by a command, automatic triggering, and scheduling. The initial check-out process of the PWE successfully completed, and initial data has been obtained. In this presentation, we introduce onboard processing technique on PWE OFA/WFC and its initial results.

  10. Components of gating charge movement and S4 voltage-sensor exposure during activation of hERG channels.

    PubMed

    Wang, Zhuren; Dou, Ying; Goodchild, Samuel J; Es-Salah-Lamoureux, Zeineb; Fedida, David

    2013-04-01

    The human ether-á-go-go-related gene (hERG) K(+) channel encodes the pore-forming α subunit of the rapid delayed rectifier current, IKr, and has unique activation gating kinetics, in that the α subunit of the channel activates and deactivates very slowly, which focuses the role of IKr current to a critical period during action potential repolarization in the heart. Despite its physiological importance, fundamental mechanistic properties of hERG channel activation gating remain unclear, including how voltage-sensor movement rate limits pore opening. Here, we study this directly by recording voltage-sensor domain currents in mammalian cells for the first time and measuring the rates of voltage-sensor modification by [2-(trimethylammonium)ethyl] methanethiosulfonate chloride (MTSET). Gating currents recorded from hERG channels expressed in mammalian tsA201 cells using low resistance pipettes show two charge systems, defined as Q(1) and Q(2), with V(1/2)'s of -55.7 (equivalent charge, z = 1.60) and -54.2 mV (z = 1.30), respectively, with the Q(2) charge system carrying approximately two thirds of the overall gating charge. The time constants for charge movement at 0 mV were 2.5 and 36.2 ms for Q(1) and Q(2), decreasing to 4.3 ms for Q(2) at +60 mV, an order of magnitude faster than the time constants of ionic current appearance at these potentials. The voltage and time dependence of Q2 movement closely correlated with the rate of MTSET modification of I521C in the outermost region of the S4 segment, which had a V(1/2) of -64 mV and time constants of 36 ± 8.5 ms and 11.6 ± 6.3 ms at 0 and +60 mV, respectively. Modeling of Q(1) and Q(2) charge systems showed that a minimal scheme of three transitions is sufficient to account for the experimental findings. These data point to activation steps further downstream of voltage-sensor movement that provide the major delays to pore opening in hERG channels.

  11. In silico Analysis of Conformational Changes Induced by Mutation of Aromatic Binding Residues: Consequences for Drug Binding in the hERG K+ Channel

    PubMed Central

    Knape, Kirsten; Linder, Tobias; Wolschann, Peter; Beyer, Anton; Stary-Weinzinger, Anna

    2011-01-01

    Pharmacological inhibition of cardiac hERG K+ channels is associated with increased risk of lethal arrhythmias. Many drugs reduce hERG current by directly binding to the channel, thereby blocking ion conduction. Mutation of two aromatic residues (F656 and Y652) substantially decreases the potency of numerous structurally diverse compounds. Nevertheless, some drugs are only weakly affected by mutation Y652A. In this study we utilize molecular dynamics simulations and docking studies to analyze the different effects of mutation Y652A on a selected number of hERG blockers. MD simulations reveal conformational changes in the binding site induced by mutation Y652A. Loss of π-π-stacking between the two aromatic residues induces a conformational change of the F656 side chain from a cavity facing to cavity lining orientation. Docking studies and MD simulations qualitatively reproduce the diverse experimentally observed modulatory effects of mutation Y652A and provide a new structural interpretation for the sensitivity differences. PMID:22194911

  12. The 5-HT(4) agonists cisapride, mosapride, and CJ-033466, a Novel potent compound, exhibit different human ether-a-go-go-related gene (hERG)-blocking activities.

    PubMed

    Toga, Tetsuo; Kohmura, Yumi; Kawatsu, Ryoichi

    2007-10-01

    The blocking effect of three 5-HT(4) agonists, cisapride, mosapride, and the newly discovered CJ-033466 on the human ether-a-go-go-related gene (hERG) channel was studied using a whole cell patch-clamp technique in HEK293 cells. Cisapride was found to be the most potent of the hERG blockers. CJ-033466 had the widest safety margin between its hERG blocking activity and 5-HT(4) agonism among the tested compounds. This suggests a lower clinical risk of cardiac arrhythmia in CJ-033466 compared with the other 2 agonists. Therefore, CJ-033466 has the potential to be a drug with higher therapeutic efficacy and less cardiac risk than both cisapride and mosapride.

  13. Analysis of the ergosterol biosynthesis pathway cloning, molecular characterization and phylogeny of lanosterol 14 α-demethylase (ERG11) gene of Moniliophthora perniciosa

    PubMed Central

    de Oliveira Ceita, Geruza; Vilas-Boas, Laurival Antônio; Castilho, Marcelo Santos; Carazzolle, Marcelo Falsarella; Pirovani, Carlos Priminho; Selbach-Schnadelbach, Alessandra; Gramacho, Karina Peres; Ramos, Pablo Ivan Pereira; Barbosa, Luciana Veiga; Pereira, Gonçalo Amarante Guimarães; Góes-Neto, Aristóteles

    2014-01-01

    The phytopathogenic fungus Moniliophthora perniciosa (Stahel) Aime & Philips-Mora, causal agent of witches’ broom disease of cocoa, causes countless damage to cocoa production in Brazil. Molecular studies have attempted to identify genes that play important roles in fungal survival and virulence. In this study, sequences deposited in the M. perniciosa Genome Sequencing Project database were analyzed to identify potential biological targets. For the first time, the ergosterol biosynthetic pathway in M. perniciosa was studied and the lanosterol 14α-demethylase gene (ERG11) that encodes the main enzyme of this pathway and is a target for fungicides was cloned, characterized molecularly and its phylogeny analyzed. ERG11 genomic DNA and cDNA were characterized and sequence analysis of the ERG11 protein identified highly conserved domains typical of this enzyme, such as SRS1, SRS4, EXXR and the heme-binding region (HBR). Comparison of the protein sequences and phylogenetic analysis revealed that the M. perniciosa enzyme was most closely related to that of Coprinopsis cinerea. PMID:25505843

  14. Spatial gradients in action potential duration created by regional magnetofection of hERG are a substrate for wavebreak and turbulent propagation in cardiomyocyte monolayers.

    PubMed

    Campbell, Katherine; Calvo, Conrado J; Mironov, Sergey; Herron, Todd; Berenfeld, Omer; Jalife, José

    2012-12-15

    Spatial dispersion of action potential duration (APD) is a substrate for the maintenance of cardiac fibrillation, but the mechanisms are poorly understood. We investigated the role played by spatial APD dispersion in fibrillatory dynamics. We used an in vitro model in which spatial gradients in the expression of ether-à-go-go-related (hERG) protein, and thus rapid delayed rectifying K(+) current (I(Kr)) density, served to generate APD dispersion, high-frequency rotor formation, wavebreak and fibrillatory conduction. A unique adenovirus-mediated magnetofection technique generated well-controlled gradients in hERG and green fluorescent protein (GFP) expression in neonatal rat ventricular myocyte monolayers. Computer simulations using a realistic neonatal rat ventricular myocyte monolayer model provided crucial insight into the underlying mechanisms. Regional hERG overexpression shortened APD and increased rotor incidence in the hERG overexpressing region. An APD profile at 75 percent repolarization with a 16.6 ± 0.72 ms gradient followed the spatial profile of hERG-GFP expression; conduction velocity was not altered. Rotors in the infected region whose maximal dominant frequency was 12.9 Hz resulted in wavebreak at the interface (border zone) between infected and non-infected regions; dominant frequency distribution was uniform when the maximal dominant frequency was <12.9 Hz or the rotors resided in the uninfected region. Regularity at the border zone was lowest when rotors resided in the infected region. In simulations, a fivefold regional increase in I(Kr) abbreviated the APD and hyperpolarized the resting potential. However, the steep APD gradient at the border zone proved to be the primary mechanism of wavebreak and fibrillatory conduction. This study provides insight at the molecular level into the mechanisms by which spatial APD dispersion contributes to wavebreak, rotor stabilization and fibrillatory conduction.

  15. Spatial gradients in action potential duration created by regional magnetofection of hERG are a substrate for wavebreak and turbulent propagation in cardiomyocyte monolayers

    PubMed Central

    Campbell, Katherine; Calvo, Conrado J; Mironov, Sergey; Herron, Todd; Berenfeld, Omer; Jalife, José

    2012-01-01

    Spatial dispersion of action potential duration (APD) is a substrate for the maintenance of cardiac fibrillation, but the mechanisms are poorly understood. We investigated the role played by spatial APD dispersion in fibrillatory dynamics. We used an in vitro model in which spatial gradients in the expression of ether-à-go-go-related (hERG) protein, and thus rapid delayed rectifying K+ current (IKr) density, served to generate APD dispersion, high-frequency rotor formation, wavebreak and fibrillatory conduction. A unique adenovirus-mediated magnetofection technique generated well-controlled gradients in hERG and green fluorescent protein (GFP) expression in neonatal rat ventricular myocyte monolayers. Computer simulations using a realistic neonatal rat ventricular myocyte monolayer model provided crucial insight into the underlying mechanisms. Regional hERG overexpression shortened APD and increased rotor incidence in the hERG overexpressing region. An APD profile at 75 percent repolarization with a 16.6 ± 0.72 ms gradient followed the spatial profile of hERG-GFP expression; conduction velocity was not altered. Rotors in the infected region whose maximal dominant frequency was ≥12.9 Hz resulted in wavebreak at the interface (border zone) between infected and non-infected regions; dominant frequency distribution was uniform when the maximal dominant frequency was <12.9 Hz or the rotors resided in the uninfected region. Regularity at the border zone was lowest when rotors resided in the infected region. In simulations, a fivefold regional increase in IKr abbreviated the APD and hyperpolarized the resting potential. However, the steep APD gradient at the border zone proved to be the primary mechanism of wavebreak and fibrillatory conduction. This study provides insight at the molecular level into the mechanisms by which spatial APD dispersion contributes to wavebreak, rotor stabilization and fibrillatory conduction. PMID:23090949

  16. The S4–S5 Linker Acts as a Signal Integrator for hERG K+ Channel Activation and Deactivation Gating

    PubMed Central

    Ng, Chai Ann; Perry, Matthew D.; Tan, Peter S.; Hill, Adam P.; Kuchel, Philip W.; Vandenberg, Jamie I.

    2012-01-01

    Human ether-à-go-go-related gene (hERG) K+ channels have unusual gating kinetics. Characterised by slow activation/deactivation but rapid inactivation/recovery from inactivation, the unique gating kinetics underlie the central role hERG channels play in cardiac repolarisation. The slow activation and deactivation kinetics are regulated in part by the S4–S5 linker, which couples movement of the voltage sensor domain to opening of the activation gate at the distal end of the inner helix of the pore domain. It has also been suggested that cytosolic domains may interact with the S4–S5 linker to regulate activation and deactivation kinetics. Here, we show that the solution structure of a peptide corresponding to the S4–S5 linker of hERG contains an amphipathic helix. The effects of mutations at the majority of residues in the S4–S5 linker of hERG were consistent with the previously identified role in coupling voltage sensor movement to the activation gate. However, mutations to Ser543, Tyr545, Gly546 and Ala548 had more complex phenotypes indicating that these residues are involved in additional interactions. We propose a model in which the S4–S5 linker, in addition to coupling VSD movement to the activation gate, also contributes to interactions that stabilise the closed state and a separate set of interactions that stabilise the open state. The S4–S5 linker therefore acts as a signal integrator and plays a crucial role in the slow deactivation kinetics of the channel. PMID:22359612

  17. PASS Reference Set Application: Lin UW (2010) TMPRSS2-ERG-PCA-PASS — EDRN Public Portal

    Cancer.gov

    Active surveillance is used to manage low-risk prostate cancer. Both PCA3 and TMPRSS2:ERG are promising biomarkers that may be associated with aggressive disease. This study examines the correlation of these biomarkers with higher cancer volume and grade determined at the time of biopsy in an active surveillance cohort.

  18. Arabidopsis ERG28 Tethers the Sterol C4-Demethylation Complex to Prevent Accumulation of a Biosynthetic Intermediate That Interferes with Polar Auxin Transport[C][W

    PubMed Central

    Mialoundama, Alexis Samba; Jadid, Nurul; Brunel, Julien; Di Pascoli, Thomas; Heintz, Dimitri; Erhardt, Mathieu; Mutterer, Jérôme; Bergdoll, Marc; Ayoub, Daniel; Van Dorsselaer, Alain; Rahier, Alain; Nkeng, Paul; Geoffroy, Philippe; Miesch, Michel; Camara, Bilal; Bouvier, Florence

    2013-01-01

    Sterols are vital for cellular functions and eukaryotic development because of their essential role as membrane constituents. Sterol biosynthetic intermediates (SBIs) represent a potential reservoir of signaling molecules in mammals and fungi, but little is known about their functions in plants. SBIs are derived from the sterol C4-demethylation enzyme complex that is tethered to the membrane by Ergosterol biosynthetic protein28 (ERG28). Here, using nonlethal loss-of-function strategies focused on Arabidopsis thaliana ERG28, we found that the previously undetected SBI 4-carboxy-4-methyl-24-methylenecycloartanol (CMMC) inhibits polar auxin transport (PAT), a key mechanism by which the phytohormone auxin regulates several aspects of plant growth, including development and responses to environmental factors. The induced accumulation of CMMC in Arabidopsis erg28 plants was associated with diagnostic hallmarks of altered PAT, including the differentiation of pin-like inflorescence, loss of apical dominance, leaf fusion, and reduced root growth. PAT inhibition by CMMC occurs in a brassinosteroid-independent manner. The data presented show that ERG28 is required for PAT in plants. Furthermore, it is accumulation of an atypical SBI that may act to negatively regulate PAT in plants. Hence, the sterol pathway offers further prospects for mining new target molecules that could regulate plant development. PMID:24326590

  19. Partial preservation of rod and cone ERG function following subretinal injection of ARPE-19 cells in RCS rats.

    PubMed

    Sauvé, Y; Pinilla, I; Lund, R D

    2006-04-01

    We quantified rod- and cone-related electroretinogram (ERG) responses following subretinal injections of the human-derived retinal pigment epithelial (hRPE) cell line ARPE-19 at age P23 to prevent progressive photoreceptor loss in the Royal College of Surgeons (RCS) rat. Culture medium-injected eyes served as sham controls. At P60, in comparison with sham-injected eyes, all recordings from hRPE-injected eyes showed preserved scotopic a- and b-waves, oscillatory potentials, double-flash-derived rod b-waves and photopic cone b-waves, and flicker critical fusion frequencies and amplitudes. Although the actual preservation did not exceed 10% of a-wave and 20% of b-wave amplitude values in non-dystrophic RCS and deteriorated rapidly by P90, rod- and cone-related ERG parameters were still recordable up to P120 unlike the virtually unresponsive sham-injected eyes.

  20. Machine learning algorithms for the prediction of hERG and CYP450 binding in drug development.

    PubMed

    Klon, Anthony E

    2010-07-01

    The cost of developing new drugs is estimated at approximately $1 billion; the withdrawal of a marketed compound due to toxicity can result in serious financial loss for a pharmaceutical company. There has been a greater interest in the development of in silico tools that can identify compounds with metabolic liabilities before they are brought to market. The two largest classes of machine learning (ML) models, which will be discussed in this review, have been developed to predict binding to the human ether-a-go-go related gene (hERG) ion channel protein and the various CYP isoforms. Being able to identify potentially toxic compounds before they are made would greatly reduce the number of compound failures and the costs associated with drug development. This review summarizes the state of modeling hERG and CYP binding towards this goal since 2003 using ML algorithms. A wide variety of ML algorithms that are comparable in their overall performance are available. These ML methods may be applied regularly in discovery projects to flag compounds with potential metabolic liabilities.

  1. The ARASE (ERG) magnetic field investigation

    NASA Astrophysics Data System (ADS)

    Matsuoka, Ayako; Teramoto, Mariko; Nomura, Reiko; Nosé, Masahito; Fujimoto, Akiko; Tanaka, Yoshimasa; Shinohara, Manabu; Nagatsuma, Tsutomu; Shiokawa, Kazuo; Obana, Yuki; Miyoshi, Yoshizumi; Mita, Makoto; Takashima, Takeshi; Shinohara, Iku

    2018-03-01

    The fluxgate magnetometer for the Arase (ERG) spacecraft mission was built to investigate particle acceleration processes in the inner magnetosphere. Precise measurements of the field intensity and direction are essential in studying the motion of particles, the properties of waves interacting with the particles, and magnetic field variations induced by electric currents. By observing temporal field variations, we will more deeply understand magnetohydrodynamic and electromagnetic ion-cyclotron waves in the ultra-low-frequency range, which can cause production and loss of relativistic electrons and ring-current particles. The hardware and software designs of the Magnetic Field Experiment (MGF) were optimized to meet the requirements for studying these phenomena. The MGF makes measurements at a sampling rate of 256 vectors/s, and the data are averaged onboard to fit the telemetry budget. The magnetometer switches the dynamic range between ± 8000 and ± 60,000 nT, depending on the local magnetic field intensity. The experiment is calibrated by preflight tests and through analysis of in-orbit data. MGF data are edited into files with a common data file format, archived on a data server, and made available to the science community. Magnetic field observation by the MGF will significantly improve our knowledge of the growth and decay of radiation belts and ring currents, as well as the dynamics of geospace storms.

  2. Changes in cortical cytoskeletal and extracellular matrix gene expression in prostate cancer are related to oncogenic ERG deregulation.

    PubMed

    Schulz, Wolfgang A; Ingenwerth, Marc; Djuidje, Carolle E; Hader, Christiane; Rahnenführer, Jörg; Engers, Rainer

    2010-09-22

    The cortical cytoskeleton network connects the actin cytoskeleton to various membrane proteins, influencing cell adhesion, polarity, migration and response to extracellular signals. Previous studies have suggested changes in the expression of specific components in prostate cancer, especially of 4.1 proteins (encoded by EPB41 genes) which form nodes in this network. Expression of EPB41L1, EPB41L2, EPB41L3 (protein: 4.1B), EPB41L4B (EHM2), EPB41L5, EPB49 (dematin), VIL2 (ezrin), and DLG1 (summarized as "cortical cytoskeleton" genes) as well as ERG was measured by quantitative RT-PCR in a well-characterized set of 45 M0 prostate adenocarcinoma and 13 benign tissues. Hypermethylation of EPB41L3 and GSTP1 was compared in 93 cancer tissues by methylation-specific PCR. Expression of 4.1B was further studied by immunohistochemistry. EPB41L1 and EPB41L3 were significantly downregulated and EPB41L4B was upregulated in cancer tissues. Low EPB41L1 or high EPB41L4B expression were associated with earlier biochemical recurrence. None of the other cortical cytoskeleton genes displayed expression changes, in particular EPB49 and VIL2, despite hints from previous studies. EPB41L3 downregulation was significantly associated with hypermethylation of its promoter and strongly correlated with GSTP1 hypermethylation. Protein 4.1B was detected most strongly in the basal cells of normal prostate epithelia. Its expression in carcinoma cells was similar to the weaker one in normal luminal cells. EPB41L3 downregulation and EPB41L4B upregulation were essentially restricted to the 22 cases with ERG overexpression. Expression changes in EPB41L3 and EPB41L4B closely paralleled those previously observed for the extracellular matrix genes FBLN1 and SPOCK1, respectively. Specific changes in the cortical cytoskeleton were observed during prostate cancer progression. They parallel changes in the expression of extracellular matrix components and all together appear to be associated with oncogenic ERG

  3. SPINK1 Overexpression in Localized Prostate Cancer: a Rare Event Inversely Associated with ERG Expression and Exclusive of Homozygous PTEN Deletion.

    PubMed

    Huang, Kuo-Cheng; Evans, Andrew; Donnelly, Bryan; Bismar, Tarek A

    2017-04-01

    SPINK1 is proposed as potential prognostic marker in prostate cancer (PCA). However, its relation to PTEN and ERG in localized PCA remains unclear. The study population consisted of two independent cohorts of men treated by radical prostatectomy for localized PCA (discovery n = 218 and validation n = 129). Patterns of association between SPINK1 and each of ERG and PTEN were evaluated by immunohistochemistry and fluorescence in situ hybridization. Associations between SPINK1 expression and various pathologic parameters and clinical outcome were also investigated. SPINK1 was expressed in 15.3 % and 10.9 % of cases in the discovery and validation cohort, respectively. SPINK expression was observed in 5.56 % of high-grade prostatic intraepithelial neoplasia and 1.1 % of adjacent morphologically benign prostatic glands. SPINK1 and ERG expression were almost exclusive, with only 1.0 % of the cases co-expressing both in the same core sample. SPINK1 interfocal and within-core heterogeneity was noted in 29.2 % and 64.6 % of cases, respectively. SPINK1 expression was not significantly associated with PTEN deletion in the two cohorts (p = 0.871 for discovery cohort and p = 0.293 for validation cohort). While SPINK1 expression did occur with hemizygous PTEN deletion, there was a complete absence of SPINK1 expression in PCA showing homozygous PTEN deletion, which was confirmed in the validation cohort (p = 0.02). Despite SPINK1's association with higher Gleason score (>7) (p = 0.02), it was not associated with other pathological parameters or biochemical recurrence post-radical prostatectomy. We documented absolute exclusivity between SPINK1 overexpression and homozygous PTEN deletion in localized PCA. SPINK1 and ERG expressions are exclusive events in PCA. SPINK1 is not of added prognostic value in localized PCA.

  4. Anti-addiction drug ibogaine inhibits hERG channels: a cardiac arrhythmia risk!

    PubMed Central

    Boehm, Stefan; Sandtner, Walter; Hilber, Karlheinz

    2016-01-01

    Ibogaine, an alkaloid derived from the African shrub Tabernanthe iboga, has shown promising anti-addictive properties in animals. Anecdotal evidence suggests that ibogaine is also anti-addictive in humans. Thus, it alleviates drug craving and impedes relapse of drug use. Although not licensed as therapeutic drug, and despite evidence that ibogaine may disturb the rhythm of the heart, this alkaloid is currently used as an anti-addiction drug in alternative medicine. Here we report that therapeutic concentrations of ibogaine reduce currents through human ERG potassium channels. Thereby, we provide a mechanism by which ibogaine may generate life-threatening cardiac arrhythmias. PMID:22458604

  5. Strong expression of the neuronal transcription factor FOXP2 is linked to an increased risk of early PSA recurrence in ERG fusion-negative cancers.

    PubMed

    Stumm, Laura; Burkhardt, Lia; Steurer, Stefan; Simon, Ronald; Adam, Meike; Becker, Andreas; Sauter, Guido; Minner, Sarah; Schlomm, Thorsten; Sirma, Hüseyin; Michl, Uwe

    2013-07-01

    Transcription factors of the forkhead box P (FOXP1-4) family have been implicated in various human cancer types before. The relevance and role of neuronal transcription factor FOXP2 in prostate cancer is unknown. A tissue microarray containing samples from more than 11 000 prostate cancers from radical prostatectomy specimens with clinical follow-up data was analysed for FOXP2 expression by immunohistochemistry. FOXP2 data were also compared with pre-existing ERG fusion (by fluorescence in situ hybridisation and immunohistochemistry) and cell proliferation (Ki67 labelling index) data. There was a moderate to strong FOXP2 protein expression in basal and secretory cells of normal prostatic glands. As compared with normal cells, FOXP2 expression was lost or reduced in 25% of cancers. Strong FOXP2 expression was linked to advanced tumour stage, high Gleason score, presence of lymph node metastases and early tumour recurrence (p<0.0001; each) in ERG fusion-negative, but not in ERG fusion-positive cancers. High FOXP2 expression was linked to high Ki67 labelling index (p<0.0001) in all cancers irrespective of ERG fusion status. These data demonstrate that similar high FOXP2 protein levels as in normal prostate epithelium exert a 'paradoxical' oncogenic role in 'non fusion-type' prostate cancer. It may be speculated that interaction of FOXP2 with members of pathways that are specifically activated in 'non fusion-type' cancers may be responsible for this phenomenon.

  6. Development of recombinant cell line co-expressing mutated Nav1.5, Kir2.1, and hERG for the safety assay of drug candidates.

    PubMed

    Fujii, Masato; Ohya, Susumu; Yamamura, Hisao; Imaizumi, Yuji

    2012-07-01

    To provide a high-throughput screening method for human ether-a-go-go-gene-related gene (hERG) K(+) channel inhibition, a new recombinant cell line, in which single action potential (AP)-induced cell death was produced by gene transfection. Mutated human cardiac Na(+) channel Nav1.5 (IFM/Q3), which shows extremely slow inactivation, and wild-type inward rectifier K(+) channel, Kir2.1, were stably co-expressed in HEK293 cells (IFM/Q3+Kir2.1). In IFM/Q3+Kir2.1, application of single electrical stimulation (ES) elicited a long AP lasting more than 30 s and led cells to die by more than 70%, whereas HEK293 co-transfected with wild-type Nav1.5 and Kir2.1 fully survived. The additional expression of hERG K(+) channels in IFM/Q3+Kir2.1 shortened the duration of evoked AP and thereby markedly reduced the cell death. The treatment of the cells with hERG channel inhibitors such as nifekalant, E-4031, cisapride, terfenadine, and verapamil, recovered the prolonged AP and dose-dependently facilitated cell death upon ES. The EC(50) values to induce the cell death were 3 µM, 19 nM, 17 nM, 74 nM, and 3 µM, respectively, whereas 10 µM nifedipine did not induce cell death. Results indicate the high utility of this cell system for hERG K(+) channel safety assay.

  7. Toward a New Gold Standard for Early Safety: Automated Temperature-Controlled hERG Test on the PatchLiner®

    PubMed Central

    Polonchuk, Liudmila

    2012-01-01

    The Patchliner® temperature-controlled automated patch clamp system was evaluated for testing drug effects on potassium currents through human ether-à-go-go related gene (hERG) channels expressed in Chinese hamster ovary cells at 35–37°C. IC50 values for a set of reference drugs were compared with those obtained using the conventional voltage clamp technique. The results showed good correlation between the data obtained using automated and conventional electrophysiology. Based on these results, the Patchliner® represents an innovative automated electrophysiology platform for conducting the hERG assay that substantially increases throughput and has the advantage of operating at physiological temperature. It allows fast, accurate, and direct assessment of channel function to identify potential proarrhythmic side effects and sets a new standard in ion channel research for drug safety testing. PMID:22303293

  8. Detection of sand encroachment patterns in desert oases. The case of Erg Chebbi (Morocco).

    PubMed

    Puy, Arnald; Herzog, Manuel; Escriche, Pedro; Marouche, Amou; Oubana, Yousef; Bubenzer, Olaf

    2018-06-11

    Desert oases are fragile agrarian areas, very vulnerable to sand encroachment by wind. Ensuring their conservation highly depends on our capacity to identify sand encroachment patterns, e.g. the origin of sand and its spatial distribution in the irrigated plots. Here we show how to tackle this issue using the case study of Erg Chebbi (Morocco), where two oases (Hassilabiad and Merzouga) are surrounded by dunes, Hamada and alluvial sediments from the Wadi Ziz. We combine field interviews with the study of wind dynamics, sediment sampling, Particle Size Distribution (PSD) tests and End-Member Modelling Analysis (EMMA). We observe that the most relevant contributor to sand encroachment is the Wadi Ziz (30%), followed by the Hamada (28%), an undetermined source of dust (25%), and the Erg dunes (16%). These genetically different sediments cluster unevenly in the oases, indicating the existence of areas with contrasting degrees of exposure to sedimentary sources. The results allow to define on solid grounds which sand source areas should be stabilized first in order to obtain the greatest reduction in sand encroachment. Our approach also provides policy-makers with better tools to identify which spots are specially vulnerable to accumulate a specific sediment, thus allowing for a more nuanced management of sand in oasis environments. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Use of the multifocal electroretinogram (mfERG) for assessing the response of 670 nm light emitting diodes (LED) photoillumination in an animal model with laser retinal injuries

    NASA Astrophysics Data System (ADS)

    DiCarlo, Cheryl D.; Brown, Jeremiah; Grado, Andres; Sankovich, James; Zwick, Harry; Lund, David J.; Stuck, Bruce E.

    2004-07-01

    There is no uniformly accepted objective method to diagnose the functional extent of retinal damage following laser eye injury and there is no uniform therapy for laser retinal injury. J.T. Eells, et al, reported the use of Light Emitting Diodes (LED) photoillumination (670 nm) for methanol-induced retinal toxicity in rats. The findings indicated a preservation of retinal architecture, as determined by histopathology and a partial functional recovery of photoreceptors, as determined by electroretinogram (ERG), in the LED exposed methanol-intoxicated rats. The purpose of this study is to use multifocal electroretinography (mfERG) to evaluate recovery of retinal function following treatment with LED photoillumination in a cynomolgus monkey laser retinal injury model. Control and LED array (670 nm) illuminated animals received macular Argon laser lesions (514 nm, 130 mW, 100 ms). LED array exposure was accomplished for 4 days for a total dose of 4 J/cm2 per day. Baseline and post-laser exposure mfERGs were performed. mfERG results for five animals post-laser injury but prior to treatment (Day 0) showed increased implicit times and P1 waveform amplitudes when compared to a combined laboratory normal and each animal's baseline normal values. In general, preliminary mfERG results of our first five subjects recorded using both the 103-hexagon and 509-hexagon patterns indicate a more rapid functional recovery in the LED illuminated animal as compared to the control by the end of the fourth day post-exposure. Research is continuing to determine if this difference in functional return is seen in additional subjects and if statistical significance exists.

  10. Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and Caucasian Americans

    DTIC Science & Technology

    2016-10-01

    enriched for European ancestry in cases with the fusion compared to cases without the fusion will be captured. A total of 400 AA individuals with CaP...variants (SNPs), admixture mapping, European and African ancestry, somatic mutations, aggressive cancer, nomograms 3. ACCOMPLISHMENTS: o What were the... European ancestry in cases with the TMPRSS2-ERG fusion, compared to cases without the fusion, will be captured. A total of 400 AA individuals will be

  11. Thermal behavior and ice-table depth within the north polar erg of Mars

    USGS Publications Warehouse

    Putzig, Nathaniel E.; Mellon, Michael T.; Herkenhoff, Kenneth E.; Phillips, Roger J.; Davis, Brian J.; Ewer, Kenneth J.; Bowers, Lauren M.

    2014-01-01

    We fully resolve a long-standing thermal discrepancy concerning the north polar erg of Mars. Several recent studies have shown that the erg’s thermal properties are consistent with normal basaltic sand overlying shallow ground ice or ice-cemented sand. Our findings bolster that conclusion by thoroughly characterizing the thermal behavior of the erg, demonstrating that other likely forms of physical heterogeneity play only a minor role, and obviating the need to invoke exotic materials. Thermal inertia as calculated from orbital temperature observations of the dunes has previously been found to be more consistent with dust-sized materials than with sand. Since theory and laboratory data show that dunes will only form out of sand-sized particles, exotic sand-sized agglomerations of dust have been invoked to explain the low values of thermal inertia. However, the polar dunes exhibit the same darker appearance and color as that of dunes found elsewhere on the planet that have thermal inertia consistent with normal sand-sized basaltic grains, whereas Martian dust deposits are generally lighter and redder. The alternative explanation for the discrepancy as a thermal effect of a shallow ice table is supported by our analysis of observations from the Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System and by forward modeling of physical heterogeneity. In addition, our results exclude a uniform composition of dark dust-sized materials, and they show that the thermal effects of the dune slopes and bright interdune materials evident in high-resolution images cannot account for the erg’s thermal behavior.

  12. Low-energy particle experiments-ion mass analyzer (LEPi) onboard the ERG (Arase) satellite

    NASA Astrophysics Data System (ADS)

    Asamura, K.; Kazama, Y.; Yokota, S.; Kasahara, S.; Miyoshi, Y.

    2018-05-01

    Low-energy ion experiments-ion mass analyzer (LEPi) is one of the particle instruments onboard the ERG satellite. LEPi is an ion energy-mass spectrometer which covers the range of particle energies from < 0.01 to 25 keV/q. Species of incoming ions are discriminated by a combination of electrostatic energy-per-charge analysis and the time-of-flight technique. The sensor has a planar field-of-view, which provides 4π steradian coverage by using the spin motion of the satellite. LEPi started its nominal observation after the initial checkout and commissioning phase in space. [Figure not available: see fulltext.

  13. Structure and Function of the Splice Variants of TMPRSS2-ERG, a Prevalent Genomic Alteration in Prostate Cancer

    DTIC Science & Technology

    2012-09-01

    apoptosis through VE-cadherin. Blood 2008; 111: 3498–3506. 20 Ellett F, Kile BT, Lieschke GJ. The role of the ETS factor erg in zebrafish...angiogenesis and endothelial apoptosis through VE-cadherin. Blood 111, 3498–3506 (2008). 46. Ellett, F., Kile , B. T. & Lieschke, G. J. The role of

  14. The Plasma Wave Experiment (PWE) on board the Arase (ERG) satellite

    NASA Astrophysics Data System (ADS)

    Kasahara, Yoshiya; Kasaba, Yasumasa; Kojima, Hirotsugu; Yagitani, Satoshi; Ishisaka, Keigo; Kumamoto, Atsushi; Tsuchiya, Fuminori; Ozaki, Mitsunori; Matsuda, Shoya; Imachi, Tomohiko; Miyoshi, Yoshizumi; Hikishima, Mitsuru; Katoh, Yuto; Ota, Mamoru; Shoji, Masafumi; Matsuoka, Ayako; Shinohara, Iku

    2018-05-01

    The Exploration of energization and Radiation in Geospace (ERG) project aims to study acceleration and loss mechanisms of relativistic electrons around the Earth. The Arase (ERG) satellite was launched on December 20, 2016, to explore in the heart of the Earth's radiation belt. In the present paper, we introduce the specifications of the Plasma Wave Experiment (PWE) on board the Arase satellite. In the inner magnetosphere, plasma waves, such as the whistler-mode chorus, electromagnetic ion cyclotron wave, and magnetosonic wave, are expected to interact with particles over a wide energy range and contribute to high-energy particle loss and/or acceleration processes. Thermal plasma density is another key parameter because it controls the dispersion relation of plasma waves, which affects wave-particle interaction conditions and wave propagation characteristics. The DC electric field also plays an important role in controlling the global dynamics of the inner magnetosphere. The PWE, which consists of an orthogonal electric field sensor (WPT; wire probe antenna), a triaxial magnetic sensor (MSC; magnetic search coil), and receivers named electric field detector (EFD), waveform capture and onboard frequency analyzer (WFC/OFA), and high-frequency analyzer (HFA), was developed to measure the DC electric field and plasma waves in the inner magnetosphere. Using these sensors and receivers, the PWE covers a wide frequency range from DC to 10 MHz for electric fields and from a few Hz to 100 kHz for magnetic fields. We produce continuous ELF/VLF/HF range wave spectra and ELF range waveforms for 24 h each day. We also produce spectral matrices as continuous data for wave direction finding. In addition, we intermittently produce two types of waveform burst data, "chorus burst" and "EMIC burst." We also input raw waveform data into the software-type wave-particle interaction analyzer (S-WPIA), which derives direct correlation between waves and particles. Finally, we introduce our

  15. Electroretinogram (ERG) to photic stimuli should be carefully distinct from photic brainstem reflex in patients with deep coma.

    PubMed

    Mitsuhashi, Masahiro; Hitomi, Takefumi; Aoyama, Akihiro; Kaido, Toshimi; Ikeda, Akio; Takahashi, Ryosuke

    2017-08-31

    Patient 1: A 35-year-old woman became deep coma because of intracranial hemorrhage after pulmonary surgery. Patient 2: A 39-year-old woman became deep coma because of cerebellar hemorrhage after hepatic surgery. Scalp-recorded digital electroencephalography (EEG) showed electrocerebral inactivity in both cases. In addition, both EEG showed repetitive discharges at bilateral frontopolar electrodes in response to photic stimuli. The amplitude and latency of the discharges was 17 μV and 24 msec in case 1, and 9 μV and 27 msec in case 2 respectively. The activity at left frontopolar electrode disappeared after coverage of the ipsilateral eye. Based on these findings, we could exclude the possibility of brainstem response and judged it as electroretinogram (ERG). Photic stimulation is a useful activation method in EEG recording, and we can also evaluate brainstem function by checking photic blink reflex if it is evoked. However, we should be cautious about the distinction of ERG from photic blink reflex when brain death is clinically suspected.

  16. Structural, functional and blood perfusion changes in the rat retina associated with elevated intraocular pressure, measured simultaneously with a combined OCT+ERG system

    PubMed Central

    Tan, Bingyao; MacLellan, Benjamin; Mason, Erik

    2018-01-01

    Acute elevation of intraocular pressure (IOP) to ischemic and non-ischemic levels can cause temporary or permanent changes in the retinal morphology, function and blood flow/blood perfusion. Previously, such changes in the retina were assessed separately with different methods in clinical studies and animal models. In this study, we used a combined OCT+ ERG system in combination with Doppler OCT and OCT angiography (OCTA) imaging protocols, in order to evaluate simultaneously and correlate changes in the retinal morphology, the retinal functional response to visual stimulation, and the retinal blood flow/blood perfusion, associated with IOP elevation to ischemic and non-ischemic levels in rats. Results from this study suggest that the inner retina responds faster to IOP elevation to levels greater than 30 mmHg with significant reduction of the total retinal blood flow (TRBF), decrease of the capillaries’ perfusion and reduction of the ON bipolar cells contribution to the ERG traces. Furthermore, this study showed that ischemic levels of IOP elevation cause an additional significant decrease in the ERG photoreceptor response in the posterior retina. Thirty minutes after IOP normalization, retinal morphology, blood flow and blood perfusion recovered to baseline values, while retinal function did not recover completely. PMID:29509807

  17. Origin of the Sinai-Negev erg, Egypt and Israel: mineralogical and geochemical evidence for the importance of the Nile and sea level history

    USGS Publications Warehouse

    Muhs, Daniel R.; Roskin, Joel; Tsoar, Haim; Skipp, Gary; Budahn, James R.; Sneh, Amihai; Porat, Naomi; Stanley, Jean-Daniel; Katra, Itzhak; Blumberg, Dan G.

    2013-01-01

    The Sinai–Negev erg occupies an area of 13,000 km2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative to K-feldspar and plagioclase. However, Sinai wadi sands have abundant calcite, whereas Nile Delta sands have little or no calcite. Overall, the mineralogical data suggest that the dunes are derived dominantly from the Nile Delta, with Sinai wadi sands being a minor contributor. Geochemical data that proxy for both the light mineral fraction (SiO2/10–Al2O3 + Na2O + K2O–CaO) and heavy mineral fraction (Fe2O3–MgO–TiO2) also indicate a dominant Nile Delta source for the dunes. Thus, we report here the first empirical evidence that the Sinai–Negev dunes are derived dominantly from the Nile Delta. Linkage of the Sinai–Negev erg to the Nile Delta as a source is consistent with the distribution of OSL ages of Negev dunes in recent studies. Stratigraphic studies show that during the Last Glacial period, when dune incursions in the Sinai–Negev erg began, what is now the Nile Delta area was characterized by a broad, sandy, minimally vegetated plain, with seasonally dry anastomosing channels. Such conditions were ideal for providing a ready source of sand for aeolian transport under what were probably much stronger glacial-age winds. With the post-glacial rise in sea level, the Nile River began to aggrade. Post-glacial sedimentation has been dominated by fine-grained silts and clays. Thus, sea level, along with favorable climatic conditions, emerges as a major influence on the timing of dune

  18. Crystallographic and magnetic structure of the novel compound ErGe 1.83

    NASA Astrophysics Data System (ADS)

    Oleksyn, O.; Schobinger-Papamantellos, P.; Ritter, C.; de Groot, C. H.; Buschow, K. H. J.

    1997-02-01

    The crystal structure and the magnetic ordering of the novel orthorhombic compound ErGe 2-x has been studied by neutron powder diffraction and magnetic measurements. The crystal structure belongs to the DyGe 1.85-type (space group Cmc2 1)·ErGe 2-x ( x = 0.17 (2)) orders antiferromagnetically below TN = 6 K and displays a metamagnetic behaviour. The magnetic cell has the same size as the chemical unit cell ( q = 0 ). The magnetic space group is Cmc2 1 (Sh 36173). At T = 1.5 K the magnetic moments of the two erbium sites have the same ordered magnetic moment values of 7.63 (6) μB/Er and are antiferromagnetically coupled leading to an uniaxial structure along the a direction.

  19. ZO-1 expression is suppressed by GM-CSF via miR-96/ERG in brain microvascular endothelial cells.

    PubMed

    Zhang, Hu; Zhang, Shuhong; Zhang, Jilin; Liu, Dongxin; Wei, Jiayi; Fang, Wengang; Zhao, Weidong; Chen, Yuhua; Shang, Deshu

    2018-05-01

    The level of granulocyte-macrophage colony-stimulating factor (GM-CSF) increases in some disorders such as vascular dementia, Alzheimer's disease, and multiple sclerosis. We previously reported that in Alzheimer's disease patients, a high level of GM-CSF in the brain parenchyma downregulated expression of ZO-1, a blood-brain barrier tight junction protein, and facilitated the infiltration of peripheral monocytes across the blood-brain barrier. However, the molecular mechanism underlying regulation of ZO-1 expression by GM-CSF is unclear. Herein, we found that the erythroblast transformation-specific (ETS) transcription factor ERG cooperated with the proto-oncogene protein c-MYC in regulation of ZO-1 transcription in brain microvascular endothelial cells (BMECs). The ERG expression was suppressed by miR-96 which was increased by GM-CSF through the phosphoinositide-3 kinase (PI3K)/Akt pathway. Inhibition of miR-96 prevented ZO-1 down-regulation induced by GM-CSF both in vitro and in vivo. Our results revealed the mechanism of ZO-1 expression reduced by GM-CSF, and provided a potential target, miR-96, which could block ZO-1 down-regulation caused by GM-CSF in BMECs.

  20. keV-Scale sterile neutrino sensitivity estimation with time-of-flight spectroscopy in KATRIN using self-consistent approximate Monte Carlo

    NASA Astrophysics Data System (ADS)

    Steinbrink, Nicholas M. N.; Behrens, Jan D.; Mertens, Susanne; Ranitzsch, Philipp C.-O.; Weinheimer, Christian

    2018-03-01

    We investigate the sensitivity of the Karlsruhe Tritium Neutrino Experiment (KATRIN) to keV-scale sterile neutrinos, which are promising dark matter candidates. Since the active-sterile mixing would lead to a second component in the tritium β-spectrum with a weak relative intensity of order sin ^2θ ≲ 10^{-6}, additional experimental strategies are required to extract this small signature and to eliminate systematics. A possible strategy is to run the experiment in an alternative time-of-flight (TOF) mode, yielding differential TOF spectra in contrast to the integrating standard mode. In order to estimate the sensitivity from a reduced sample size, a new analysis method, called self-consistent approximate Monte Carlo (SCAMC), has been developed. The simulations show that an ideal TOF mode would be able to achieve a statistical sensitivity of sin ^2θ ˜ 5 × 10^{-9} at one σ , improving the standard mode by approximately a factor two. This relative benefit grows significantly if additional exemplary systematics are considered. A possible implementation of the TOF mode with existing hardware, called gated filtering, is investigated, which, however, comes at the price of a reduced average signal rate.

  1. The Novel PIM1 Inhibitor NMS-P645 Reverses PIM1-Dependent Effects on TMPRSS2/ERG Positive Prostate Cancer Cells And Shows Anti-Proliferative Activity in Combination with PI3K Inhibition.

    PubMed

    Mologni, Luca; Magistroni, Vera; Casuscelli, Francesco; Montemartini, Marisa; Gambacorti-Passerini, Carlo

    2017-01-01

    PIM1 is over-expressed in multiple tumors, including prostate cancer (PCa). PIM1 upregulation is mediated by direct binding of the ERG transcription factor to its promoter. About 50% of PCa cases are characterized by the presence of the TMPRSS2/ERG fusion, leading to ERG over-expression and thus to PIM1 transcriptional activation. PIM kinases are considered as weak oncogenes, but when combined with additional genetic alterations can induce strong transforming effects. Here we show anti-proliferative activity of the newly described PIM1 inhibitor NMS-P645 in combination with the PI3K inhibitor GDC-0941 in TMPRSS2/ERG positive and negative PCa cells. Treatment with NMS-P645 alone can reverse PIM1-mediated pro-survival signals in prostate cells, such as activation of STAT3 through Tyr705 phosphorylation and resistance to taxane-based treatments, but does not exert a strong anti-tumoral effect. However, the simultaneous treatment with NMS-P645 and GDC-0941 induces a significant anti-proliferative response in PCa cells. These results support the use of combination strategies with PIM and PI3K inhibitors as effective treatment for PCa cases.

  2. Effects of dopamine D1 receptor blockade on the ERG b- and d-waves during blockade of ionotropic GABA receptors.

    PubMed

    Popova, Elka; Kostov, Momchil; Kupenova, Petia

    2016-01-01

    Some data indicate that the dopaminergic and GABAergic systems interact in the vertebrate retina, but the type of interactions is not well understood. In this study we investigated the effect of dopamine D 1 receptor blockade by 75 μM SCH 23390 on the electroretinographic ON (b-wave) and OFF (d-wave) responses in intact frog eyecup preparations and in eyecups where the ionotropic GABA receptors were blocked by 50 μM picrotoxin. Student's t -test, One-way repeated measures ANOVA with Bonferroni post-hoc test and Two-way ANOVA were used for statistical evaluation of the data. We found that SCH 23390 alone significantly enhanced the amplitude of the b- and d-waves without altering their latency. The effect developed rapidly and was fully expressed within 8-11 min after the blocker application. Picrotoxin alone also markedly enhanced the amplitude of the ERG ON and OFF responses and increased their latency significantly. The effect was fully expressed within 25-27 min after picrotoxin application and remained very stable in the next 20 min. The effects of SCH 23390 and picrotoxin are similar to that reported in our previous studies. When SCH 23390 was applied on the background of the fully developed picrotoxin effect, it diminished the amplitude of the b- and d-waves in comparison to the corresponding values obtained during application of picrotoxin alone. Our results demonstrate that the enhancing effect of D 1 receptor blockade on the amplitude of the ERG b- and d-waves is not evident during the ionotropic GABA receptor blockade, indicating an interaction between these neurotransmitter systems in the frog retina. We propose that the inhibitory effect of endogenous dopamine mediated by D 1 receptors on the ERG ON and OFF responses in the frog retina may be due to the dopamine-evoked GABA release.

  3. Effect of pathologic revision and Ki67 and ERG immunohistochemistry on predicting radical prostatectomy outcome in men initially on active surveillance.

    PubMed

    Bokhorst, Leonard P; Roobol, Monique J; Bangma, Chris H; van Leenders, Geert J

    2017-07-01

    To investigate if pathologic biopsy reevaluation and implementation of immunohistochemical biomarkers could improve prediction of radical prostatectomy outcome in men initially on active surveillance. Biopsy specimens from diagnosis until switching to radical prostatectomy in men initially on active surveillance in the Dutch part of the Prostate cancer Research International Active Surveillance (PRIAS) study were collected and revised by a single pathologist. Original and revised biopsy Gleason score were compared and correlated with radical prostatectomy Gleason score. Biopsy specimens were immunohistochemically stained for Ki67 and ERG. Predictive ability of clinical characteristics and biomarkers on Gleason ≥7 or ≥pT3 on radical prostatectomy was tested using logistic regression and ROC curve analysis. A total of 150 biopsies in 95 men were revised. In 13% of diagnostic or second-to-last biopsies and 20% of the last biopsies on active surveillance revision of Gleason score resulted in change of recommendation (ie, active treatment or active surveillance). Concordance with Gleason score on radical prostatectomy was however similar for both the revised and original Gleason on biopsy. Ki67 and ERG were not statistically significant predictors of Gleason ≥7 or ≥pT3 on radical prostatectomy. Although interobserver differences in pathology reporting on biopsy could result in a change of management strategy in approximately 13-20% of men on active surveillance, both pathological revision and tested biomarkers (Ki67 and ERG) did not improve prediction of outcome on radical prostatectomy. Undersampling of most aggressive tumor remains the main focus in order to increase accurate grading at time of treatment decision making. © 2017 Wiley Periodicals, Inc.

  4. Comparative evaluation of urinary PCA3 and TMPRSS2: ERG scores and serum PHI in predicting prostate cancer aggressiveness.

    PubMed

    Tallon, Lucile; Luangphakdy, Devillier; Ruffion, Alain; Colombel, Marc; Devonec, Marian; Champetier, Denis; Paparel, Philippe; Decaussin-Petrucci, Myriam; Perrin, Paul; Vlaeminck-Guillem, Virginie

    2014-07-30

    It has been suggested that urinary PCA3 and TMPRSS2:ERG fusion tests and serum PHI correlate to cancer aggressiveness-related pathological criteria at prostatectomy. To evaluate and compare their ability in predicting prostate cancer aggressiveness, PHI and urinary PCA3 and TMPRSS2:ERG (T2) scores were assessed in 154 patients who underwent radical prostatectomy for biopsy-proven prostate cancer. Univariate and multivariate analyses using logistic regression and decision curve analyses were performed. All three markers were predictors of a tumor volume≥0.5 mL. Only PHI predicted Gleason score≥7. T2 score and PHI were both independent predictors of extracapsular extension(≥pT3), while multifocality was only predicted by PCA3 score. Moreover, when compared to a base model (age, digital rectal examination, serum PSA, and Gleason sum at biopsy), the addition of both PCA3 score and PHI to the base model induced a significant increase (+12%) when predicting tumor volume>0.5 mL. PHI and urinary PCA3 and T2 scores can be considered as complementary predictors of cancer aggressiveness at prostatectomy.

  5. The N–Terminal Tail of hERG Contains an Amphipathic α–Helix That Regulates Channel Deactivation

    PubMed Central

    Mobli, Mehdi; Ke, Ying; Kuchel, Philip W.; King, Glenn F.; Stock, Daniela; Vandenberg, Jamie I.

    2011-01-01

    The cytoplasmic N–terminal domain of the human ether–a–go–go related gene (hERG) K+ channel is critical for the slow deactivation kinetics of the channel. However, the mechanism(s) by which the N–terminal domain regulates deactivation remains to be determined. Here we show that the solution NMR structure of the N–terminal 135 residues of hERG contains a previously described Per–Arnt–Sim (PAS) domain (residues 26–135) as well as an amphipathic α–helix (residues 13–23) and an initial unstructured segment (residues 2–9). Deletion of residues 2–25, only the unstructured segment (residues 2–9) or replacement of the α–helix with a flexible linker all result in enhanced rates of deactivation. Thus, both the initial flexible segment and the α–helix are required but neither is sufficient to confer slow deactivation kinetics. Alanine scanning mutagenesis identified R5 and G6 in the initial flexible segment as critical for slow deactivation. Alanine mutants in the helical region had less dramatic phenotypes. We propose that the PAS domain is bound close to the central core of the channel and that the N–terminal α–helix ensures that the flexible tail is correctly orientated for interaction with the activation gating machinery to stabilize the open state of the channel. PMID:21249148

  6. Contribution of Interstitial Deletion of 21q22.2-3 per se to Prostate Cancer Progression in Tumors Harboring TMPRSS2-ERG Translocations

    DTIC Science & Technology

    2015-12-01

    harboring TMPRSS2-ERG translocations PRINCIPAL INVESTIGATOR: Yan Dong CONTRACTING ORGANIZATION: Tulane University New Orleans , LA 70112...AND ADDRESS(ES) Tulane University AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 6823 Saint Charles Ave New Orleans , LA 70118-5665 9

  7. Computational Models for Understanding of Structure, Function and Pharmacology of the Cardiac Potassium Channel Kv11.1 (hERG).

    PubMed

    Wacker, Soren; Noskov, Sergei Yu; Perissinotti, Laura L

    2017-01-01

    The rapid delayed rectifier current IKr is one of the major K+ currents involved in repolarization of the human cardiac action potential. Various inherited or drug-induced forms of the long QT syndrome (LQTS) in humans are linked to functional and structural modifications in the IKr conducting channels. IKr is carried by the potassium channel Kv11.1 encoded by the gene KCNH2 (commonly referred to as human ether-a-go-go-related gene or hERG) [1, 2]. The first necessary step for predicting emergent drug effects on the heart is determining and modeling the binding thermodynamics and kinetics of primary and major off-target drug interactions with subcellular targets. The bulk of drugs that target hERG channels are known to have complex interactions at the atomic scale. Accordingly, one of the goals for this review is to provide comprehensive guide in the universe of computational models aiming to refine our understanding of structure-function relations in Kv11.1 and its isoforms. The special emphasis is placed on the mapping of drug binding sites and tentative mechanisms of channel inhibition and activation by drugs. An overview over recent structural models and mapping of binding sites for blockers and activators of IKr current along with the discussion on agreements and discrepancies among different models is presented. There is an apparent reciprocity or feedback loop between drug binding and action potential of the cardiac myocytes. Thus one has to connect drug binding to a particular receptor so that its functional consequences impact on the action potential duration. The natural pathway is to develop multi-scale models that connect between receptor and cellular scales. The potential for such multi-scale model development is discussed through the lens of common gating models. Accordingly, the second part of this review covers an ongoing development of the kinetic models of gating transitions and cardiac ion currents carried by hERG channels with and without drug

  8. X-linked retinoschisis: RS1 mutation severity and age affect the ERG phenotype in a cohort of 68 affected male subjects.

    PubMed

    Bowles, Kristen; Cukras, Catherine; Turriff, Amy; Sergeev, Yuri; Vitale, Susan; Bush, Ronald A; Sieving, Paul A

    2011-11-29

    To assess the effect of age and RS1 mutation on the phenotype of X-linked retinoschisis (XLRS) subjects using the clinical electroretinogram (ERG) in a cross-sectional analysis. Sixty-eight XLRS males 4.5 to 55 years of age underwent genotyping, and the retinoschisis (RS1) mutations were classified as less severe (27 subjects) or more severe (41 subjects) based on the putative impact on the protein. ERG parameters of retinal function were analyzed by putative mutation severity with age as a continuous variable. The a-wave amplitude remained greater than the lower limit of normal (mean, -2 SD) for 72% of XLRS males and correlated with neither age nor mutation class. However, b-wave and b/a-ratio amplitudes were significantly lower in the more severe than in the less severe mutation groups and in older than in younger subjects. Subjects up to 10 years of age with more severe RS1 mutations had significantly greater b-wave amplitudes and faster a-wave trough implicit times than older subjects in this group. RS1 mutation putative severity and age both had significant effects on retinal function in XLRS only in the severe mutation group, as judged by ERG analysis of the b-wave amplitude and the b/a-ratio, whereas the a-wave amplitude remained normal in most. A new observation was that increasing age (limited to those aged 55 and younger) caused a significant delay in XLRS b-wave onset (i.e., a-wave implicit time), even for those who retained considerable b-wave amplitudes. The delayed b-wave onset suggested that dysfunction of the photoreceptor synapse or of bipolar cells increases with age of XLRS subjects.

  9. Dynamic control of ERG20 expression combined with minimized endogenous downstream metabolism contributes to the improvement of geraniol production in Saccharomyces cerevisiae.

    PubMed

    Zhao, Jianzhi; Li, Chen; Zhang, Yan; Shen, Yu; Hou, Jin; Bao, Xiaoming

    2017-01-31

    Microbial production of monoterpenes provides a promising substitute for traditional chemical-based methods, but their production is lagging compared with sesquiterpenes. Geraniol, a valuable monoterpene alcohol, is widely used in cosmetic, perfume, pharmaceutical and it is also a potential gasoline alternative. Previously, we constructed a geraniol production strain by engineering the mevalonate pathway together with the expression of a high-activity geraniol synthase. In this study, we further improved the geraniol production through reducing the endogenous metabolism of geraniol and controlling the precursor geranyl diphosphate flux distribution. The deletion of OYE2 (encoding an NADPH oxidoreductase) or ATF1 (encoding an alcohol acetyltransferase) both involving endogenous conversion of geraniol to other terpenoids, improved geraniol production by 1.7-fold or 1.6-fold in batch fermentation, respectively. In addition, we found that direct down-regulation of ERG20 expression, the branch point regulating geranyl diphosphate flux, does not improve geraniol production. Therefore, we explored dynamic control of ERG20 expression to redistribute the precursor geranyl diphosphate flux and achieved a 3.4-fold increase in geraniol production after optimizing carbon source feeding. Furthermore, the combination of dynamic control of ERG20 expression and OYE2 deletion in LEU2 prototrophic strain increased geraniol production up to 1.69 g/L with pure ethanol feeding in fed-batch fermentation, which is the highest reported production in engineered yeast. An efficient geraniol production platform was established by reducing the endogenous metabolism of geraniol and by controlling the flux distribution of the precursor geranyl diphosphate. The present work also provides a production basis to synthesis geraniol-derived chemicals, such as monoterpene indole alkaloids.

  10. Stabilization of the Activated hERG Channel Voltage Sensor by Depolarization Involves the S4-S5 Linker.

    PubMed

    Thouta, Samrat; Hull, Christina M; Shi, Yu Patrick; Sergeev, Valentine; Young, James; Cheng, Yen M; Claydon, Thomas W

    2017-01-24

    Slow deactivation of hERG channels is critical for preventing cardiac arrhythmia yet the mechanistic basis for the slow gating transition is unclear. Here, we characterized the temporal sequence of events leading to voltage sensor stabilization upon membrane depolarization. Progressive increase in step depolarization duration slowed voltage-sensor return in a biphasic manner (τ fast = 34 ms, τ slow  = 2.5 s). The faster phase of voltage-sensor return slowing correlated with the kinetics of pore opening. The slower component occurred over durations that exceeded channel activation and was consistent with voltage sensor relaxation. The S4-S5 linker mutation, G546L, impeded the faster phase of voltage sensor stabilization without attenuating the slower phase, suggesting that the S4-S5 linker is important for communications between the pore gate and the voltage sensor during deactivation. These data also demonstrate that the mechanisms of pore gate-opening-induced and relaxation-induced voltage-sensor stabilization are separable. Deletion of the distal N-terminus (Δ2-135) accelerated off-gating current, but did not influence the relative contribution of either mechanism of stabilization of the voltage sensor. Lastly, we characterized mode-shift behavior in hERG channels, which results from stabilization of activated channel states. The apparent mode-shift depended greatly on recording conditions. By measuring slow activation and deactivation at steady state we found the "true" mode-shift to be ∼15 mV. Interestingly, the "true" mode-shift of gating currents was ∼40 mV, much greater than that of the pore gate. This demonstrates that voltage sensor return is less energetically favorable upon repolarization than pore gate closure. We interpret this to indicate that stabilization of the activated voltage sensor limits the return of hERG channels to rest. The data suggest that this stabilization occurs as a result of reconfiguration of the pore gate upon opening

  11. Structure and Function of the Splice Variants of TMPRSS2-ERG, a Prevalent Genomic Alteration in Prostate Cancer

    DTIC Science & Technology

    2009-09-01

    binding ETS domain) and five type II (without ETS domain). Fusion-positive type I– and type II–containing phages were amplified with T3 and T7 primers...will be performed to identify the authentic 3’ UTRs from the mRNA pool from CaP patient specimens. Using phage excision strategy, we will use to... phage DNA sequences plasmids (cDNA) clones were generated by using phage excision strategy. Figure 1. ERG splice variants in prostate cancer

  12. Strategies for high-altitude adaptation revealed from high-quality draft genome of non-violacein producing Janthinobacterium lividum ERGS5:01.

    PubMed

    Kumar, Rakshak; Acharya, Vishal; Singh, Dharam; Kumar, Sanjay

    2018-01-01

    A light pink coloured bacterial strain ERGS5:01 isolated from glacial stream water of Sikkim Himalaya was affiliated to Janthinobacterium lividum based on 16S rRNA gene sequence identity and phylogenetic clustering. Whole genome sequencing was performed for the strain to confirm its taxonomy as it lacked the typical violet pigmentation of the genus and also to decipher its survival strategy at the aquatic ecosystem of high elevation. The PacBio RSII sequencing generated genome of 5,168,928 bp with 4575 protein-coding genes and 118 RNA genes. Whole genome-based multilocus sequence analysis clustering, in silico DDH similarity value of 95.1% and, the ANI value of 99.25% established the identity of the strain ERGS5:01 (MCC 2953) as a non-violacein producing J. lividum . The genome comparisons across genus Janthinobacterium revealed an open pan-genome with the scope of the addition of new orthologous cluster to complete the genomic inventory. The genomic insight provided the genetic basis of freezing and frequent freeze-thaw cycle tolerance and, for industrially important enzymes. Extended insight into the genome provided clues of crucial genes associated with adaptation in the harsh aquatic ecosystem of high altitude.

  13. Interactions between charged residues in the transmembrane segments of the voltage-sensing domain in the hERG channel.

    PubMed

    Zhang, M; Liu, J; Jiang, M; Wu, D-M; Sonawane, K; Guy, H R; Tseng, G-N

    2005-10-01

    Studies on voltage-gated K channels such as Shaker have shown that positive charges in the voltage-sensor (S4) can form salt bridges with negative charges in the surrounding transmembrane segments in a state-dependent manner, and different charge pairings can stabilize the channels in closed or open states. The goal of this study is to identify such charge interactions in the hERG channel. This knowledge can provide constraints on the spatial relationship among transmembrane segments in the channel's voltage-sensing domain, which are necessary for modeling its structure. We first study the effects of reversing S4's positive charges on channel activation. Reversing positive charges at the outer (K525D) and inner (K538D) ends of S4 markedly accelerates hERG activation, whereas reversing the 4 positive charges in between either has no effect or slows activation. We then use the 'mutant cycle analysis' to test whether D456 (outer end of S2) and D411 (inner end of S1) can pair with K525 and K538, respectively. Other positive charges predicted to be able, or unable, to interact with D456 or D411 are also included in the analysis. The results are consistent with predictions based on the distribution of these charged residues, and confirm that there is functional coupling between D456 and K525 and between D411 and K538.

  14. Functional Characterization of the Protein Product of the Prostate Carcinoma Gene Fusion TMPRSS2:ERG Using the Proteomic and Microarray Analyses

    DTIC Science & Technology

    2009-07-01

    AD_________________ ( Leave blank) Award Number: W81XWH-08-1-0048 TITLE: Functional...cancer human cell lines, T98G and U2OS, in order to test for cell-line specific effects . After infecting equal number of cells with the viruses carrying... Guava ™ FACS analyzer with the ViaCount™ kit (Millipore). As shown in Fig. 7, VCaP cells infected with ERG or ERGa once again failed to proliferate

  15. Total petroleum systems of the Grand Erg/Ahnet Province, Algeria and Morocco; the Tanezzuft-Timimoun, Tanezzuft-Ahnet, Tanezzuft-Sbaa, Tanezzuft Mouydir, Tanezzuft-Benoud, and Tanezzuft-Bechar/Abadla

    USGS Publications Warehouse

    Klett, T.R.

    2000-01-01

    Undiscovered, conventional oil and gas resources were assessed within total petroleum systems of the Grand Erg/Ahnet Province (2058) as part of the U.S. Geological Survey World Petroleum Assessment 2000. The majority of the Grand Erg/ Ahnet Province is in western Algeria; a very small portion extends into Morocco. The province includes the Timimoun Basin, Ahnet Basin, Sbaa Basin, Mouydir Basin, Benoud Trough, Bechar/Abadla Basin(s), and part of the Oued Mya Basin. Although several petroleum systems may exist within each of these basins, only seven ?composite? total petroleum systems were identified. Each total petroleum system occurs in a separate basin, and each comprises a single assessment unit. The main source rocks are the Silurian Tanezzuft Formation (or lateral equivalents) and Middle to Upper Devonian mudstone. Maturation history and the major migration pathways from source to reservoir are unique to each basin. The total petroleum systems were named after the oldest major source rock and the basin in which it resides. The estimated means of the undiscovered conventional petroleum volumes in total petroleum systems of the Grand Erg/ Ahnet Province are as follows: [MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids] Total Petroleum System MMBO BCFG MMBNGL Tanezzuft-Timimoun 31 1,128 56 Tanezzuft-Ahnet 34 2,973 149 Tanezzuft-Sbaa 162 645 11 Tanezzuft-Mouydir 12 292 14 Tanezzuft-Benoud 72 2,541 125 Tanezzuft-Bechar/Abadla 16 441 22

  16. Multifocal ERG reveals long distance effects of a local bleach in the retina.

    PubMed

    Kretschmann, U; Tornow, R P; Zrenner, E

    1998-06-01

    To examine the distribution of ERG-activity in the central visual field after local bleaching of the fovea, multifocal electroretinograms were recorded in eight normal volunteers before, during and after recurrent light exposure. During bleaching (90% bleached pigment), the response density (scalar product) of the foveal area (0-2 degrees eccentricity) decreased from 10.7 +/- 3.5 to 4.1 +/- 1.9 nV/degree2 (P < 0.001). The average activity in the extrafoveal macular area was unchanged, while the amplitudes were frequently (in 53 of 54 areas) enhanced at 5-30.5 degrees eccentricity. Here the average response density changed from 3.1 +/- 0.9 to 3.5 +/- 1.0 nV/degree2 (P < 0.001). A fast recovery of foveal responses after cessation of bleaching occurred. Besides a strong decrease of response in the directly bleached area, local bleaching led to enhanced activity mainly 3-27 degrees distant from the bleached area.

  17. Mechanistic Insight into Human ether-à-go-go-related Gene (hERG) K+ Channel Deactivation Gating from the Solution Structure of the EAG Domain

    PubMed Central

    Muskett, Frederick W.; Thouta, Samrat; Thomson, Steven J.; Bowen, Alexander; Stansfeld, Phillip J.; Mitcheson, John S.

    2011-01-01

    Human ether-à-go-go-related gene (hERG) K+ channels have a critical role in cardiac repolarization. hERG channels close (deactivate) very slowly, and this is vital for regulating the time course and amplitude of repolarizing current during the cardiac action potential. Accelerated deactivation is one mechanism by which inherited mutations cause long QT syndrome and potentially lethal arrhythmias. hERG deactivation is highly dependent upon an intact EAG domain (the first 135 amino acids of the N terminus). Importantly, deletion of residues 2–26 accelerates deactivation to a similar extent as removing the entire EAG domain. These and other experiments suggest the first 26 residues (NT1–26) contain structural elements required to slow deactivation by stabilizing the open conformation of the pore. Residues 26–135 form a Per-Arnt-Sim domain, but a structure for NT1–26 has not been forthcoming, and little is known about its site of interaction on the channel. In this study, we present an NMR structure for the entire EAG domain, which reveals that NT1–26 is structurally independent from the Per-Arnt-Sim domain and contains a stable amphipathic helix with one face being positively charged. Mutagenesis and electrophysiological studies indicate that neutralizing basic residues and breaking the amphipathic helix dramatically accelerate deactivation. Furthermore, scanning mutagenesis and molecular modeling studies of the cyclic nucleotide binding domain suggest that negatively charged patches on its cytoplasmic surface form an interface with the NT1–26 domain. We propose a model in which NT1–26 obstructs gating motions of the cyclic nucleotide binding domain to allosterically stabilize the open conformation of the pore. PMID:21135103

  18. High-energy electron experiments (HEP) aboard the ERG (Arase) satellite

    NASA Astrophysics Data System (ADS)

    Mitani, Takefumi; Takashima, Takeshi; Kasahara, Satoshi; Miyake, Wataru; Hirahara, Masafumi

    2018-05-01

    This paper reports the design, calibration, and operation of high-energy electron experiments (HEP) aboard the exploration of energization and radiation in geospace (ERG) satellite. HEP detects 70 keV-2 MeV electrons and generates a three-dimensional velocity distribution for these electrons in every period of the satellite's rotation. Electrons are detected by two instruments, namely HEP-L and HEP-H, which differ in their geometric factor (G-factor) and range of energies they detect. HEP-L detects 70 keV-1 MeV electrons and its G-factor is 9.3 × 10-4 cm2 sr at maximum, while HEP-H observes 0.7-2 MeV electrons and its G-factor is 9.3 × 10-3 cm2 sr at maximum. The instruments utilize silicon strip detectors and application-specific integrated circuits to readout the incident charge signal from each strip. Before the launch, we calibrated the detectors by measuring the energy spectra of all strips using γ-ray sources. To evaluate the overall performance of the HEP instruments, we measured the energy spectra and angular responses with electron beams. After HEP was first put into operation, on February 2, 2017, it was demonstrated that the instruments performed normally. HEP began its exploratory observations with regard to energization and radiation in geospace in late March 2017. The initial results of the in-orbit observations are introduced briefly in this paper.[Figure not available: see fulltext.

  19. Calcium channel blocker use and risk of prostate cancer by TMPRSS2:ERG gene fusion status

    PubMed Central

    Geybels, Milan S.; McCloskey, Karen D.; Mills, Ian G.; Stanford, Janet L.

    2017-01-01

    Background Calcium channel blockers (CCBs) may affect prostate cancer (PCa) growth by various mechanisms including those related to androgens. The fusion of the androgen-regulated gene TMPRSS2 and the oncogene ERG (TMPRSS2:ERG or T2E) is common in PCa, and prostate tumors that harbor the gene fusion are believed to represent a distinct disease subtype. We studied the association of CCB use with the risk of PCa, and molecular subtypes of PCa defined by T2E status. Methods Participants were residents of King County, Washington, recruited for population-based case–control studies (1993–1996 or 2002–2005). Tumor T2E status was determined by fluorescence in situ hybridization using tumor tissue specimens from radical prostatectomy. Detailed information on use of CCBs and other variables was obtained through in-person interviews. Binomial and polytomous logistic regression were used to generate odds ratios (ORs) and 95% confidence intervals (CIs). Results The study includes 1,747 PCa patients and 1,635 age-matched controls. A subset of 563 patients treated with radical prostatectomy had T2E status determined, of which 295 were T2E positive (52%). Use of CCBs (ever vs. never) was not associated with overall PCa risk. However, among European-American men, users had a reduced risk of higher-grade PCa (Gleason scores ≥7: adjusted OR = 0.64; 95% CI: 0.44–0.95). Further, use of CCBs was associated with a reduced risk of T2E positive PCa (adjusted OR = 0.38; 95% CI: 0.19–0.78), but was not associated with T2E negative PCa. Conclusions This study found suggestive evidence that use of CCBs is associated with reduced relative risks for higher Gleason score and T2E positive PCa. Future studies of PCa etiology should consider etiologic heterogeneity as PCa subtypes may develop through different causal pathways. PMID:27753122

  20. Incorporating sprint training with endurance training improves anaerobic capacity and 2,000-m Erg performance in trained oarsmen.

    PubMed

    Stevens, Alexander W J; Olver, Terry T; Lemon, Peter W R

    2015-01-01

    A 2,000-m time-trial performance, aerobic capacity, and anaerobic capacity were assessed in 16 trained oarsmen after sprint interval training (SIT) replaced a portion of an endurance-based training program (EBTSIT) vs. an endurance-based program alone (EBTAlone). The EBTSIT involved 10 SIT sessions over 4 weeks, in addition to 12 continuous exercise sessions, 2 anaerobic threshold exercise sessions, and 4 strength training sessions. The EBTAlone consisted of 20 continuous, 6 anaerobic threshold, 2 interval exercise sessions, and 8 strength training sessions. Time-trial performance (2,000-m erg performance) improved with EBTSIT (baseline = 414.6 ± 18.5, post = 410.6 ± 17.5 seconds; p < 0.001) but only approached significance in EBTAlone (baseline = 413.0 ± 27.7, post = 411.4 ± 27.9 seconds; p = 0.06). In a 60-second "all-out" anaerobic capacity test, peak power output (PPO) increased significantly with EBTSIT (PPO: EBTSIT: baseline = 566 ± 82, post = 623 ± 60 W; p = 0.02) but not with EBTAlone (EBTAlone: baseline = 603 ± 81, post = 591 ± 123 W; p = 0.59). Changes in average power output (APO) also approached significance (p = 0.07) (APO: EBTSIT: baseline = 508 ± 48, post = 530 ± 52 W; EBTAlone: baseline = 532 ± 55, post = 533 ± 68 W). Neither group experienced any change in aerobic capacity ((Equation is included in full-text article.)or ventilatory threshold; p ≥ 0.16). We conclude that replacing a portion of EBT with SIT can improve both 2,000-m erg performance and anaerobic capacity, while maintaining aerobic fitness in trained oarsmen. Incorporating SIT within endurance training programs may be useful during periods of low-volume training, to improve performance without sacrificing aerobic capacity.

  1. NMR solution structure of the N-terminal domain of hERG and its interaction with the S4-S5 linker

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Qingxin; Gayen, Shovanlal; Chen, Angela Shuyi

    Research highlights: {yields} The N-terminal domain (NTD, eag domain) containing 135 residues of hERG was expressed and purified from E. coli cells. {yields} Solution structure of NTD was determined with NMR spectroscopy. {yields} The alpha-helical region (residues 13-23) was demonstrated to possess the characteristics of an amphipathic helix. {yields} NMR titration confirmed the interaction between NTD and the peptide from the S4-S5 linker. -- Abstract: The human Ether-a-go-go Related Gene (hERG) potassium channel mediates the rapid delayed rectifier current (IKr) in the cardiac action potential. Mutations in the 135 amino acid residue N-terminal domain (NTD) cause channel dysfunction or mis-translocation.more » To study the structure of NTD, it was overexpressed and purified from Escherichia coli cells using affinity purification and gel filtration chromatography. The purified protein behaved as a monomer under purification conditions. Far- and near-UV, circular dichroism (CD) and solution nuclear magnetic resonance (NMR) studies showed that the purified protein was well-folded. The solution structure of NTD was obtained and the N-terminal residues 13-23 forming an amphipathic helix which may be important for the protein-protein or protein-membrane interactions. NMR titration experiment also demonstrated that residues from 88 to 94 in NTD are important for the molecular interaction with the peptide derived from the S4-S5 linker.« less

  2. Correlation of Visually Evoked Functional and Blood Flow Changes in the Rat Retina Measured With a Combined OCT+ERG System.

    PubMed

    Tan, Bingyao; Mason, Erik; MacLellan, Benjamin; Bizheva, Kostadinka K

    2017-03-01

    To correlate visually evoked functional and blood flow changes in the rat retina measured simultaneously with a combined optical coherence tomography and electroretinography system (OCT+ERG). Male Brown Norway (n = 6) rats were dark adapted and anesthetized with ketamine/xylazine. Visually evoked changes in the retinal blood flow (RBF) and functional response were measured simultaneously with an OCT+ERG system with 3-μm axial resolution in retinal tissue and 47-kHz image acquisition rate. Both single flash (10 and 200 ms) and flicker (10 Hz, 20% duty cycle, 1- and 2-second duration) stimuli were projected onto the retina with a custom visual stimulator, integrated into the OCT imaging probe. Total axial RBF was calculated from circular Doppler OCT scans by integrating over the arterial and venal flow. Temporary increase in the RBF was observed with the 10- and 200-ms continuous stimuli (∼1% and ∼4% maximum RBF change, respectively) and the 10-Hz flicker stimuli (∼8% for 1-second duration and ∼10% for 2-second duration). Doubling the flicker stimulus duration resulted in ∼25% increase in the RBF peak magnitude with no significant change in the peak latency. Single flash (200 ms) and flicker (10 Hz, 1 second) stimuli of the same illumination intensity and photon flux resulted in ∼2× larger peak RBF magnitude and ∼25% larger RBF peak latency for the flicker stimulus. Short, single flash and flicker stimuli evoked measureable RBF changes with larger RBF magnitude and peak latency observed for the flicker stimuli.

  3. Kv11.1 (hERG)-induced cardiotoxicity: a molecular insight from a binding kinetics study of prototypical Kv11.1 (hERG) inhibitors

    PubMed Central

    Yu, Z; IJzerman, A P; Heitman, L H

    2015-01-01

    Background and Purpose Drug-induced arrhythmia due to blockade of the Kv11.1 channel (also known as the hERG K+ channel) is a frequent side effect. Previous studies have primarily focused on equilibrium parameters, i.e. affinity or potency, of drug candidates at the channel. The aim of this study was to determine the kinetics of the interaction with the channel for a number of known Kv11.1 blockers and to explore a possible correlation with the affinity or physicochemical properties of these compounds. Experimental Approach The affinity and kinetic parameters of 15 prototypical Kv11.1 inhibitors were evaluated in a number of [3H]-dofetilide binding assays. The lipophilicity (logKW-C8) and membrane partitioning (logKW-IAM) of these compounds were determined by means of HPLC analysis. Key Results A novel [3H]-dofetilide competition association assay was set up and validated, which allowed us to determine the binding kinetics of the Kv11.1 blockers used in this study. Interestingly, the compounds' affinities (Ki values) were correlated to their association rates rather than dissociation rates. Overall lipophilicity or membrane partitioning of the compounds were not correlated to their affinity or rate constants for the channel. Conclusions and Implications A compound's affinity for the Kv11.1 channel is determined by its rate of association with the channel, while overall lipophilicity and membrane affinity are not. In more general terms, our findings provide novel insights into the mechanism of action for a compound's activity at the Kv11.1 channel. This may help to elucidate how Kv11.1-induced cardiotoxicity is governed and how it can be circumvented in the future. PMID:25296617

  4. A complicated story of frost and wind: Present-day gully activity within the north polar erg, Mar

    NASA Astrophysics Data System (ADS)

    Diniega, Serina; Hansen, Candice; Allen, Amanda; Grisby, Nathan; Li, Zheyu Joey

    2016-10-01

    Analyses of high-resolution observations have shown that the dunes within the martian north polar erg (AKA Olympia Undae) are currently very active on seasonal and yearly timescales, with 20-60% of the dunes within five polar dune fields undergoing the formation of alcove-apron features each Mars year. Previous studies have hypothesized formation mechanisms, based on observations of when new alcove and alcove-apron features form within an individual field through one Mars year. However, results are ill-constrained (and thus different hypotheses have been proposed) as the polar hood and winter night mean very few images are taken during the actual period of activity. In this study, we mitigate this limitation by examining several fields over several Mars years -- thus bringing aggregated results as well as detailed correlation checks against environmental conditions and seasonal processes to bear on the problem. From this, we propose a new process that appears consistent with all observations: (1) small alcoves form along the dune brink in the autumn (under the polar hood) due to instabilities induced by the night-formation and morning-sublimation of frost. As autumn progresses, the seasonal frost layer builds over the altered dune slope. (2) In the early spring, sublimation activity is concentrated and/or enhanced over these alcoves, causing further erosion and the formation of larger alcove-apron features. From the planform dimensions of the newly formed alcoves, we can estimate the volume of sand moved down the dune slope during one period of activity and estimate the aeolian sediment flux by looking at how quickly the alcoves are erased. We find that, over a Mars year, the amount of material moved via alcove-apron activity and via the wind are both comparable to aeolian sand flux estimates over dunes within lower-latitude regions of Mars. Thus it appears that the formation of alcoves-aprons is a significant mechanism for dune advancement and evolution within the

  5. Nontoxic concentration of ceftazidime and flomoxef sodium for intravitreal use--evaluated by in-vitro ERG.

    PubMed

    Tanabe, J; Kitano, K; Suzuki, T; Okayama, Y; Mochizuki, K; Kawasaki, K

    1990-01-01

    The effects of ceftazidime (CAZ) and flomoxef sodium (FMOX) on the in-vitro electroretinogram (ERG) of albino rabbits were studied. The a-wave, the b-wave and the oscillatory potential (OP) were unchanged by 0.3mM (0.19mg/ml) CAZ-containing solution. The OP was suppressed by 0.5mM (0.32mg/ml) CAZ. The a-wave, the b-wave and the OP were unchanged by 0.5mM (0.26mg/ml) FMOX. The OP was suppressed and its peak latency was delayed by 2mM (0.52mg/ml) FMOX. The concentration of 0.3mM (0.19mg/ml) CAZ was higher than its minimum inhibitory concentration (MIC) against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Serratia marcescens and Propionibacterium acnes. The concentration of 0.5mM (0.26mg/ml) FMOX was higher than its MIC against Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens and Propionibacterium acnes.

  6. Functional characterization of a novel hERG variant in a family with recurrent sudden infant death syndrome: Retracting a genetic diagnosis.

    PubMed

    Sergeev, Valentine; Perry, Frances; Roston, Thomas M; Sanatani, Shubhayan; Tibbits, Glen F; Claydon, Thomas W

    2018-03-01

    Long QT syndrome (LQTS) is the most common cardiac ion channelopathy and has been found to be responsible for approximately 10% of sudden infant death syndrome (SIDS) cases. Despite increasing use of broad panels and now whole exome sequencing (WES) in the investigation of SIDS, the probability of identifying a pathogenic mutation in a SIDS victim is low. We report a family-based study who are afflicted by recurrent SIDS in which several members harbor a variant, p.Pro963Thr, in the C-terminal region of the human-ether-a-go-go (hERG) gene, published to be responsible for cases of LQTS type 2. Functional characterization was undertaken due to the variable phenotype in carriers, the discrepancy with published cases, and the importance of identifying a cause for recurrent deaths in a single family. Studies of the mutated ion channel in in vitro heterologous expression systems revealed that the mutation has no detectable impact on membrane surface expression, biophysical gating properties such as activation, deactivation and inactivation, or the amplitude of the protective current conducted by hERG channels during early repolarization. These observations suggest that the p.Pro963Thr mutation is not a monogenic disease-causing LQTS mutation despite evidence of co-segregation in two siblings affected by SIDS. Our findings demonstrate some of the potential pitfalls in post-mortem molecular testing and the importance of functional testing of gene variants in determining disease-causation, especially where the impacts of cascade screening can affect multiple generations. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Can one measure the Cosmic Neutrino Background?

    NASA Astrophysics Data System (ADS)

    Faessler, Amand; Hodák, Rastislav; Kovalenko, Sergey; Šimkovic, Fedor

    The Cosmic Microwave Background (CMB) yields information about our Universe at around 380,000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter, the Cosmic Neutrino Background (CNB) should give information about a much earlier time of our Universe, around one second after the BB. Probably, the most promising method to “see” the CNB is the capture of the electron neutrinos from the Background by Tritium, which then decays into 3He and an electron with the energy of the the Q-value = 18.562keV plus the electron neutrino rest mass. The “KArlsruhe TRItium Neutrino” (KATRIN) experiment, which is in preparation, seems presently the most sensitive proposed method for measuring the electron antineutrino mass. At the same time, KATRIN can also look by the reaction νe(˜ 1.95K) +3H →3He + e-(Q = 18.6keV + m νec2). The capture of the Cosmic Background Neutrinos (CNB) should show in the electron spectrum as a peak by the electron neutrino rest mass above Q. Here, the possibility to see the CNB with KATRIN is studied. A detection of the CNB by KATRIN seems not to be possible at the moment. But KATRIN should be able to determine an upper limit for the local electron neutrino density of the CNB.

  8. Can one measure the Cosmic Neutrino Background?

    NASA Astrophysics Data System (ADS)

    Faessler, Amand; Hodák, Rastislav; Kovalenko, Sergey; Šimkovic, Fedor

    The Cosmic Microwave Background (CMB) yields information about our Universe at around 380,000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter, the Cosmic Neutrino Background (CNB) should give information about a much earlier time of our Universe, around one second after the BB. Probably, the most promising method to "see" the CNB is the capture of the electron neutrinos from the Background by Tritium, which then decays into 3He and an electron with the energy of the the Q-value = 18.562 keV plus the electron neutrino rest mass. The "KArlsruhe TRItium Neutrino" (KATRIN) experiment, which is in preparation, seems presently the most sensitive proposed method for measuring the electron antineutrino mass. At the same time, KATRIN can also look by the reaction νe(˜1.95K) + 3H → 3He + e-(Q = 18.6keV + mνec2). The capture of the Cosmic Background Neutrinos (CNB) should show in the electron spectrum as a peak by the electron neutrino rest mass above Q. Here, the possibility to see the CNB with KATRIN is studied. A detection of the CNB by KATRIN seems not to be possible at the moment. But KATRIN should be able to determine an upper limit for the local electron neutrino density of the CNB.

  9. Evaluation of urinary prostate cancer antigen-3 (PCA3) and TMPRSS2-ERG score changes when starting androgen-deprivation therapy with triptorelin 6-month formulation in patients with locally advanced and metastatic prostate cancer.

    PubMed

    Martínez-Piñeiro, Luis; Schalken, Jack A; Cabri, Patrick; Maisonobe, Pascal; de la Taille, Alexandre

    2014-10-01

    To assess prostate cancer antigen-3 (PCA3) and TMPRSS2-ERG scores in patients with advanced and metastatic prostate cancer at baseline and after 6 months of treatment with triptorelin 22.5 mg, and analyse these scores in patient-groups defined by different disease characteristics. The Triptocare study was a prospective, open-label, multicentre, single-arm, Phase III study of triptorelin 22.5 mg in men with locally advanced or metastatic prostate cancer, who were naïve to androgen-deprivation therapy (ADT). The primary objective was to model the urinary PCA3 change at 6 months, according to baseline variables. Other outcome measures included urinary PCA3 and TMPRSS2-ERG scores and statuses, and serum testosterone and prostate-specific antigen (PSA) levels at baseline and at 1, 3 and 6 months after initiation of ADT. Safety was assessed by recording adverse events and changes in laboratory parameters. The intent-to-treat population comprised 322 patients; 39 (12.1%) had non-assessable PCA3 scores at baseline, and 109/322 (33.9%), 215/313 (68.7%) and 232/298 (77.9%) had non-assessable PCA3 scores at 1, 3 and 6 months, respectively. Baseline Gleason score was the only variable associated with non-assessability of PCA3 score at 6 months (P = 0.017) - the hazard of having a non-assessable PCA3 score at 6 months was 1.824-fold higher (95% confidence interval 1.186-2.805) in patients with a Gleason score ≥8 vs those with a Gleason score ≤6. The median PCA3 scores at baseline were significantly higher in patients aged ≥65 years vs those aged <65 years and in patients with a serum PSA level <100 ng/mL vs those with serum PSA level of >200 ng/mL. The median PCA3 score was significantly lower in patients with metastasis than in patients with no metastasis or unknown metastasis status. TMPRSS2-ERG scores ≥35 were considered positive (n = 149 [51.6%]). Age, presence of metastasis, PSA level and Gleason score at baseline were not associated with a significant

  10. Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network

    NASA Astrophysics Data System (ADS)

    Shiokawa, Kazuo; Katoh, Yasuo; Hamaguchi, Yoshiyuki; Yamamoto, Yuka; Adachi, Takumi; Ozaki, Mitsunori; Oyama, Shin-Ichiro; Nosé, Masahito; Nagatsuma, Tsutomu; Tanaka, Yoshimasa; Otsuka, Yuichi; Miyoshi, Yoshizumi; Kataoka, Ryuho; Takagi, Yuki; Takeshita, Yuhei; Shinbori, Atsuki; Kurita, Satoshi; Hori, Tomoaki; Nishitani, Nozomu; Shinohara, Iku; Tsuchiya, Fuminori; Obana, Yuki; Suzuki, Shin; Takahashi, Naoko; Seki, Kanako; Kadokura, Akira; Hosokawa, Keisuke; Ogawa, Yasunobu; Connors, Martin; Michael Ruohoniemi, J.; Engebretson, Mark; Turunen, Esa; Ulich, Thomas; Manninen, Jyrki; Raita, Tero; Kero, Antti; Oksanen, Arto; Back, Marko; Kauristie, Kirsti; Mattanen, Jyrki; Baishev, Dmitry; Kurkin, Vladimir; Oinats, Alexey; Pashinin, Alexander; Vasilyev, Roman; Rakhmatulin, Ravil; Bristow, William; Karjala, Marty

    2017-11-01

    The plasmas (electrons and ions) in the inner magnetosphere have wide energy ranges from electron volts to mega-electron volts (MeV). These plasmas rotate around the Earth longitudinally due to the gradient and curvature of the geomagnetic field and by the co-rotation motion with timescales from several tens of hours to less than 10 min. They interact with plasma waves at frequencies of mHz to kHz mainly in the equatorial plane of the magnetosphere, obtain energies up to MeV, and are lost into the ionosphere. In order to provide the global distribution and quantitative evaluation of the dynamical variation of these plasmas and waves in the inner magnetosphere, the PWING project (study of dynamical variation of particles and waves in the inner magnetosphere using ground-based network observations, http://www.isee.nagoya-u.ac.jp/dimr/PWING/) has been carried out since April 2016. This paper describes the stations and instrumentation of the PWING project. We operate all-sky airglow/aurora imagers, 64-Hz sampling induction magnetometers, 40-kHz sampling loop antennas, and 64-Hz sampling riometers at eight stations at subauroral latitudes ( 60° geomagnetic latitude) in the northern hemisphere, as well as 100-Hz sampling EMCCD cameras at three stations. These stations are distributed longitudinally in Canada, Iceland, Finland, Russia, and Alaska to obtain the longitudinal distribution of plasmas and waves in the inner magnetosphere. This PWING longitudinal network has been developed as a part of the ERG (Arase)-ground coordinated observation network. The ERG (Arase) satellite was launched on December 20, 2016, and has been in full operation since March 2017. We will combine these ground network observations with the ERG (Arase) satellite and global modeling studies. These comprehensive datasets will contribute to the investigation of dynamical variation of particles and waves in the inner magnetosphere, which is one of the most important research topics in recent space

  11. LBNL Neutrino Astrophysics

    Science.gov Websites

    The KATRIN experiment The KATRIN experiment is designed to make a direct measurement of the mass experiment, scaled up by an order of magnitude in size, precision and tritium source intensity from previous experiments. Visit the experiment home page for more information. Gallery SimpleViewer requires JavaScript and

  12. Dune-slope activity due to frost and wind throughout the north polar erg, Mars

    PubMed Central

    DINIEGA, SERINA; HANSEN, CANDICE J.; ALLEN, AMANDA; GRIGSBY, NATHAN; LI, ZHEYU; PEREZ, TYLER; CHOJNACKI, MATTHEW

    2018-01-01

    Repeat, high-resolution imaging of dunes within the Martian north polar erg have shown that these dune slopes are very active, with alcoves forming along the dune brink each Mars year. In some areas, a few hundred cubic metres of downslope sand movement have been observed, sometimes moving the dune brink ‘backwards’. Based on morphological and activity-timing similarities of these north polar features to southern dune gullies, identifying the processes forming these features is likely to have relevance for understanding the general evolution/modification of dune gullies. To determine alcove-formation model constraints, we have surveyed seven dune fields, each over 1–4 Mars winters. Consistent with earlier reports, we found that alcove-formation activity occurs during the autumn–winter seasons, before or while the stable seasonal frost layer is deposited. We propose a new model in which alcove formation occurs during the autumn, and springtime sublimation activity then enhances the feature. Summertime winds blow sand into the new alcoves, erasing small alcoves over a few Mars years. Based on the observed rate of alcove erasure, we estimated the effective aeolian sand transport flux. From this, we proposed that alcove formation may account for 2–20% of the total sand movement within these dune fields. PMID:29731538

  13. Dune-slope activity due to frost and wind throughout the north polar erg, Mars.

    PubMed

    Diniega, Serina; Hansen, Candice J; Allen, Amanda; Grigsby, Nathan; Li, Zheyu; Perez, Tyler; Chojnacki, Matthew

    2017-01-01

    Repeat, high-resolution imaging of dunes within the Martian north polar erg have shown that these dune slopes are very active, with alcoves forming along the dune brink each Mars year. In some areas, a few hundred cubic metres of downslope sand movement have been observed, sometimes moving the dune brink 'backwards'. Based on morphological and activity-timing similarities of these north polar features to southern dune gullies, identifying the processes forming these features is likely to have relevance for understanding the general evolution/modification of dune gullies. To determine alcove-formation model constraints, we have surveyed seven dune fields, each over 1-4 Mars winters. Consistent with earlier reports, we found that alcove-formation activity occurs during the autumn-winter seasons, before or while the stable seasonal frost layer is deposited. We propose a new model in which alcove formation occurs during the autumn, and springtime sublimation activity then enhances the feature. Summertime winds blow sand into the new alcoves, erasing small alcoves over a few Mars years. Based on the observed rate of alcove erasure, we estimated the effective aeolian sand transport flux. From this, we proposed that alcove formation may account for 2-20% of the total sand movement within these dune fields.

  14. A key role for peroxynitrite-mediated inhibition of cardiac ERG (Kv11.1) K+ channels in carbon monoxide–induced proarrhythmic early afterdepolarizations

    PubMed Central

    Al-Owais, Moza M.; Hettiarachchi, Nishani T.; Kirton, Hannah M.; Hardy, Matthew E.; Boyle, John P.; Scragg, Jason L.; Steele, Derek S.; Peers, Chris

    2017-01-01

    Exposure to CO causes early afterdepolarization arrhythmias. Previous studies in rats have indicated that arrhythmias arose as a result of augmentation of the late Na+ current. The purpose of the present study was to examine the basis for CO-induced arrhythmias in guinea pig myocytes in which action potentials (APs) more closely resemble those of human myocytes. Whole-cell current- and voltage-clamp recordings were made from isolated guinea pig myocytes as well as from human embryonic kidney 293 (HEK293) cells that express wild-type or a C723S mutant form of ether-a-go-go–related gene (ERG; Kv11.1). We also monitored the formation of peroxynitrite (ONOO−) in HEK293 cells fluorimetrically. CO—applied as the CO-releasing molecule, CORM-2—prolonged the APs and induced early afterdepolarizations in guinea pig myocytes. In HEK293 cells, CO inhibited wild-type, but not C723S mutant, Kv11.1 K+ currents. Inhibition was prevented by an antioxidant, mitochondrial inhibitors, or inhibition of NO formation. CO also raised ONOO− levels, an effect that was reversed by the ONOO− scavenger, FeTPPS [5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrinato-iron(III)], which also prevented the CO inhibition of Kv11.1 currents and abolished the effects of CO on Kv11.1 tail currents and APs in guinea pig myocytes. Our data suggest that CO induces arrhythmias in guinea pig cardiac myocytes via the ONOO−-mediated inhibition of Kv11.1 K+ channels.—Al-Owais, M. M., Hettiarachchi, N. T., Kirton, H. M., Hardy, M. E., Boyle, J. P., Scragg, J. L., Steele, D. S., Peers, C. A key role for peroxynitrite-mediated inhibition of cardiac ERG (Kv11.1) K+ channels in carbon monoxide–induced proarrhythmic early afterdepolarizations. PMID:28743763

  15. SHOCK AND VIBRATION COMPUTER PROGRAMS. REVIEWS AND SUMMARIES

    DTIC Science & Technology

    1975-01-01

    hurricanes , special for- mulas nay have to be conaidered. Ice Ice load la usually specified by the thickness of the ice and by the ice- breaking force...Vibration Institute 5401 Katrine Downers Grove, Illinois 60515 Attn: Dr. Ronald. L. Eshleman, Director Critical Speeds ot a Rptor-Bearlng System...Instruction manual, and exanples. Contact: The Vibration Institute 5401 Katrine Downers Grove, 111. 60515 KOUTIMi MACHINSW 477 Attn; Dr. Ronald L

  16. Fluvial channel-belts, floodbasins, and aeolian ergs in the Precambrian Meall Dearg Formation (Torridonian of Scotland): Inferring climate regimes from pre-vegetation clastic rock records

    NASA Astrophysics Data System (ADS)

    Lebeau, Lorraine E.; Ielpi, Alessandro

    2017-07-01

    The interpretation of climate regimes from facies analysis of Precambrian clastic rocks has been challenging thus far, hindering full reconstructions of landscape dynamics in pre-vegetation environments. Yet, comparisons between different and co-active sedimentary realms, including fluvial-channelised, floodplain, and aeolian hold the potential to shed further light on this thematic. This research discusses a fluvial-aeolian record from the 1.2 Ga Meall Dearg Formation, part of the classic Torridonian succession of Scotland. Tentatively considered to date as a braided-fluvial deposit, this unit is here reappraised as the record of fluvial channel-belts, floodbasins, and aeolian ergs. Fluvial deposits with abundant transitional- to upper-flow regime structures (mostly cross-beds with tangential sets and plane/antidunal beds) and simple, low-relief sediment bars indicate a low-sinuosity, ephemeral style. Floodbasin deposits consist of plane and cross-beds ubiquitously bounded by symmetrical ripples, and rare sediment bars related to the progradation of splay complexes in temporary flooded depressions. Aeolian deposits occur nearby basement topography, and are dominated by large-scale, pin-stripe laminated cross-beds, indicative of intermountain ergs. Neither ephemeral-fluvial nor intermountain aeolian systems can be considered as reliable indicators of local climate, since their sedimentary style is respectively controlled by catchment size and shape, and basin topography relative to groundwater tables. Contrarily, the occurrence of purely clastic - rather than carbonate or evaporitic - floodplain strata can be more confidently related to humid regimes. In brief, this study provides new insight into an overlooked portion of the Torridonian succession of Scotland, and discusses climate inferences for Precambrian clastic terrestrial rocks.

  17. Alleviating CYP and hERG liabilities by structure optimization of dihydrofuran-fused tricyclic benzo[d]imidazole series - Potent, selective and orally efficacious microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors: Part-2.

    PubMed

    Muthukaman, Nagarajan; Deshmukh, Sanjay; Tambe, Macchindra; Pisal, Dnyandeo; Tondlekar, Shital; Shaikh, Mahamadhanif; Sarode, Neelam; Kattige, Vidya G; Sawant, Pooja; Pisat, Monali; Karande, Vikas; Honnegowda, Srinivasa; Kulkarni, Abhay; Behera, Dayanidhi; Jadhav, Satyawan B; Sangana, Ramchandra R; Gudi, Girish S; Khairatkar-Joshi, Neelima; Gharat, Laxmikant A

    2018-04-15

    In an effort to identify CYP and hERG clean mPGES-1 inhibitors from the dihydrofuran-fused tricyclic benzo[d]imidazole series lead 7, an extensive structure-activity relationship (SAR) studies were performed. Optimization of A, D and E-rings in 7 afforded many potent compounds with human whole blood potency in the range of 160-950 nM. Selected inhibitors 21d, 21j, 21m, 21n, 21p and 22b provided selectivity against COX-enzymes and mPGES-1 isoforms (mPGES-2 and cPGES) along with sufficient selectivity against prostanoid synthases. Most of the tested analogs demonstrated required metabolic stability in liver microsomes, low hERG and CYP liability. Oral pharmacokinetics and bioavailability of lead compounds 21j, 21m and 21p are discussed in multiple species like rat, guinea pig, dog, and cynomolgus monkey. Besides, these compounds revealed low to moderate activity against human pregnane X receptor (hPXR). The selected lead 21j further demonstrated in vivo efficacy in acute hyperalgesia (ED 50 : 39.6 mg/kg) and MIA-induced osteoarthritic pain models (ED 50 : 106 mg/kg). Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Acute alteration of cardiac ECG, action potential, I{sub Kr} and the human ether-a-go-go-related gene (hERG) K{sup +} channel by PCB 126 and PCB 77

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Mi-Hyeong; Park, Won Sun; Jo, Su-Hyun, E-mail: suhyunjo@kangwon.ac.kr

    2012-07-01

    Polychlorinated biphenyls (PCBs) have been known as serious persistent organic pollutants (POPs), causing developmental delays and motor dysfunction. We have investigated the effects of two PCB congeners, 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) and 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) on ECG, action potential, and the rapidly activating delayed rectifier K{sup +} current (I{sub Kr}) of guinea pigs' hearts, and hERG K{sup +} current expressed in Xenopus oocytes. PCB 126 shortened the corrected QT interval (QTc) of ECG and decreased the action potential duration at 90% (APD{sub 90}), and 50% of repolarization (APD{sub 50}) (P < 0.05) without changing the action potential duration at 20% (APD{submore » 20}). PCB 77 decreased APD{sub 20} (P < 0.05) without affecting QTc, APD{sub 90}, and APD{sub 50}. The PCB 126 increased the I{sub Kr} in guinea-pig ventricular myocytes held at 36 °C and hERG K{sup +} current amplitude at the end of the voltage steps in voltage-dependent mode (P < 0.05); however, PCB 77 did not change the hERG K{sup +} current amplitude. The PCB 77 increased the diastolic Ca{sup 2+} and decreased Ca{sup 2+} transient amplitude (P < 0.05), however PCB 126 did not change. The results suggest that PCB 126 shortened the QTc and decreased the APD{sub 90} possibly by increasing I{sub Kr}, while PCB 77 decreased the APD{sub 20} possibly by other modulation related with intracellular Ca{sup 2+}. The present data indicate that the environmental toxicants, PCBs, can acutely affect cardiac electrophysiology including ECG, action potential, intracellular Ca{sup 2+}, and channel activity, resulting in toxic effects on the cardiac function in view of the possible accumulation of the PCBs in human body. -- Highlights: ► PCBs are known as serious environmental pollutants and developmental disruptors. ► PCB 126 shortened QT interval of ECG and action potential duration. ► PCB 126 increased human ether-a-go-go-related K{sup +} current and I{sub Kr

  19. NS1643 Interacts around L529 of hERG to Alter Voltage Sensor Movement on the Path to Activation

    PubMed Central

    Guo, Jiqing; Cheng, Yen May; Lees-Miller, James P.; Perissinotti, Laura L.; Claydon, Tom W.; Hull, Christina M.; Thouta, Samrat; Roach, Daniel E.; Durdagi, Serdar; Noskov, Sergei Y.; Duff, Henry J.

    2015-01-01

    Activators of hERG1 such as NS1643 are being developed for congenital/acquired long QT syndrome. Previous studies identify the neighborhood of L529 around the voltage-sensor as a putative interacting site for NS1643. With NS1643, the V1/2 of activation of L529I (−34 ± 4 mV) is similar to wild-type (WT) (−37 ± 3 mV; P > 0.05). WT and L529I showed no difference in the slope factor in the absence of NS1643 (8 ± 0 vs. 9 ± 0) but showed a difference in the presence of NS1643 (9 ± 0.3 vs. 22 ± 1; P < 0.01). Voltage-clamp-fluorimetry studies also indicated that in L529I, NS1643 reduces the voltage-sensitivity of S4 movement. To further assess mechanism of NS1643 action, mutations were made in this neighborhood. NS1643 shifts the V1/2 of activation of both K525C and K525C/L529I to hyperpolarized potentials (−131 ± 4 mV for K525C and −120 ± 21 mV for K525C/L529I). Both K525C and K525C/K529I had similar slope factors in the absence of NS1643 (18 ± 2 vs. 34 ± 5, respectively) but with NS1643, the slope factor of K525C/L529I increased from 34 ± 5 to 71 ± 10 (P < 0.01) whereas for K525C the slope factor did not change (18 ± 2 at baseline and 16 ± 2 for NS1643). At baseline, K525R had a slope factor similar to WT (9 vs. 8) but in the presence of NS1643, the slope factor of K525R was increased to 24 ± 4 vs. 9 ± 0 mV for WT (P < 0.01). Molecular modeling indicates that L529I induces a kink in the S4 voltage-sensor helix, altering a salt-bridge involving K525. Moreover, docking studies indicate that NS1643 binds to the kinked structure induced by the mutation with a higher affinity. Combining biophysical, computational, and electrophysiological evidence, a mechanistic principle governing the action of some activators of hERG1 channels is proposed. PMID:25809253

  20. Novel Terminal Bipheny-Based Diapophytoene Desaturases (CrtN) Inhibitors as Anti-MRSA/VISR/LRSA Agents with Reduced hERG Activity.

    PubMed

    Li, Baoli; Ni, Shuaishuai; Mao, Fei; Chen, Feifei; Liu, Yifu; Wei, Hanwen; Chen, Wenhua; Zhu, Jin; Lan, Lefu; Li, Jian

    2018-01-11

    CrtN has been identified as an attractive and druggable target for treating pigmented Staphylococcus aureus infections. More than 100 new compounds were synthesized, which target the overwhelming the defects of the CrtN inhibitor 1. Analogues 23a and 23b demonstrated a significant activity against pigmented S. aureus Newman and 13 MRSA strains (IC 50 = 0.02-10.5 nM), along with lower hERG inhibition (IC 50 > 30 μM, ∼10-fold decrease in comparison with 1). Furthermore, 23a and 23b were confirmed to reduce the staphylococcal load in the kidney and heart in a mouse model with normal treatment deeper than pretreatment ones, comparable even with vancomycin and linezolid. Remarkably, 23a could strongly block the pigment biosynthesis of these nine multidrug-resistant MRSA strains, including excellent activity against LRSA strains and VISA strains in vivo, and all of which demonstrated that 23a has a huge potential against intractable MRSA, VISA, and LRSA issues as a therapeutic drug.

  1. Magnetic Search Coil (MSC) of Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite

    NASA Astrophysics Data System (ADS)

    Ozaki, Mitsunori; Yagitani, Satoshi; Kasahara, Yoshiya; Kojima, Hirotsugu; Kasaba, Yasumasa; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Sasaki, Takashi; Yumoto, Takahiro

    2018-05-01

    This paper presents detailed performance values of the Magnetic Search Coil (MSC) that is part of the Plasma Wave Experiment on board the Arase (ERG) satellite. The MSC consists of a three-axis search coil magnetometer with a 200-mm-long magnetic core. The MSC plays a central role in the magnetic field observations, particularly for whistler mode chorus and hiss waves in a few kHz frequency range, which may cause local acceleration and/or rapid loss of radiation belt electrons. Accordingly, the MSC was carefully designed and developed to operate well in harsh radiation environments. To ascertain the wave-normal vectors, polarizations, and refractive indices of the plasma waves in a wide frequency band, the output signals detected by the MSC are fed into the two different wave receivers: one is the WaveForm Capture/Onboard Frequency Analyzer for waveform and spectrum observations in the frequency range from a few Hz up to 20 kHz, and the other is the High Frequency Analyzer for spectrum observations in the frequency range from 10 to 100 kHz. The noise equivalent magnetic induction of the MSC is 20 {fT/Hz}^{1/2} at a frequency of 2 kHz, and the null depth of directionality is - 40 dB, which is equivalent to an angular error less than 1°. The MSC on board the Arase satellite is the first experiment using a current-sensitive preamplifier for probing the plasma waves in the radiation belts.[Figure not available: see fulltext.

  2. Obesity and Prostate Cancer Risk According to Tumor TMPRSS2:ERG Gene Fusion Status

    PubMed Central

    Egbers, Lieke; Luedeke, Manuel; Rinckleb, Antje; Kolb, Suzanne; Wright, Jonathan L.; Maier, Christiane; Neuhouser, Marian L.; Stanford, Janet L.

    2015-01-01

    The T2E gene fusion, formed by fusion of the transmembrane protease, serine 2, gene (TMPRSS2) with the erythroblast transformation-specific (ETS)-related gene (ERG), is found in approximately 50% of prostate cancers and may characterize distinct molecular subtypes of prostate cancer with different etiologies. We investigated the relationship between body mass index (BMI; weight (kg)/height (m)2) and prostate cancer risk by T2E status. Study participants were residents of King County, Washington, recruited for 2 population-based case-control studies conducted in 1993–1996 and 2002–2005. Tumor T2E status was determined for 563 prostate cancer patients who underwent radical prostatectomy. Information on weight, height, and covariables was obtained through in-person interviews. We performed polytomous logistic regression to calculate odds ratios and 95% confidence intervals for T2E-positive and -negative prostate cancer. Comparing the highest BMI quartile with the lowest, inverse associations were observed between recent (≥29.7 vs. <24.5: odds ratio = 0.66, 95% confidence interval: 0.45, 0.97) and maximum (≥31.8 vs. <25.9: odds ratio = 0.69, 95% confidence interval: 0.47, 1.02) BMI and the risk of T2E-positive prostate cancer. No significant associations were seen for men with T2E-negative tumors. This study provides evidence that obesity is specifically associated with reduced risk of developing androgen-responsive T2E fusion–positive tumors. The altered steroid hormone profile in obese men may contribute to this inverse association. PMID:25852077

  3. High-resolution mapping of D16Led-1, Gart, Gas-r, Cbr, Pcp-4, and Erg on distal mouse chromosome 16

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mjaatvedt, A.E.; Citron, M.P.; Reeves, R.H.

    1993-08-01

    More than 500 backcross progeny from four inter-subspecific backcrosses were typed for six markers on distal mouse chromosome 16. Five of these represented genes that mapped within the Sod-1 to Ets-2 interval, which was shown previously to contain the weaver (wv) gene. The map order, including previously mapped reference markers, is (cen)-D16H21S16-D16Led-1-App-Sod-1-Gart-Gas-4-Cbr-wv-Pep-4-Erg-Ets-2. This gene order recapitulates the order of the genes on human chromosome 21 where known. Two of these markers further define the region containing the weaver gene to a 3.9-cM segment between Cbr and Pcp-4. In addition, Pep-4 was localized to human chromosome 21 by the presence ofmore » a human-specific restriction fragment in WAV-17, a mouse-human somatic cell hybrid with human chromosome 31 as the only human contribution. 26 refs., 3 figs., 3 tabs.« less

  4. Kinesin spindle protein (KSP) inhibitors. Part 3: synthesis and evaluation of phenolic 2,4-diaryl-2,5-dihydropyrroles with reduced hERG binding and employment of a phosphate prodrug strategy for aqueous solubility.

    PubMed

    Garbaccio, Robert M; Fraley, Mark E; Tasber, Edward S; Olson, Christy M; Hoffman, William F; Arrington, Kenneth L; Torrent, Maricel; Buser, Carolyn A; Walsh, Eileen S; Hamilton, Kelly; Schaber, Michael D; Fernandes, Christine; Lobell, Robert B; Tao, Weikang; South, Vicki J; Yan, Youwei; Kuo, Lawrence C; Prueksaritanont, Thomayant; Slaughter, Donald E; Shu, Cathy; Heimbrook, David C; Kohl, Nancy E; Huber, Hans E; Hartman, George D

    2006-04-01

    2,4-Diaryl-2,5-dihydropyrroles have been discovered to be novel, potent and water-soluble inhibitors of KSP, an emerging therapeutic target for the treatment of cancer. A potential concern for these basic KSP inhibitors (1 and 2) was hERG binding that can be minimized by incorporation of a potency-enhancing C2 phenol combined with neutral N1 side chains. Aqueous solubility was restored to these, and other, non-basic inhibitors, through a phosphate prodrug strategy.

  5. Patients With Long-QT Syndrome Caused by Impaired hERG-Encoded Kv11.1 Potassium Channel Have Exaggerated Endocrine Pancreatic and Incretin Function Associated With Reactive Hypoglycemia

    PubMed Central

    Hyltén-Cavallius, Louise; Iepsen, Eva W.; Wewer Albrechtsen, Nicolai J.; Svendstrup, Mathilde; Lubberding, Anniek F.; Hartmann, Bolette; Jespersen, Thomas; Linneberg, Allan; Christiansen, Michael; Vestergaard, Henrik; Pedersen, Oluf; Holst, Jens J.; Kanters, Jørgen K.

    2017-01-01

    Background: Loss-of-function mutations in hERG (encoding the Kv11.1 voltage-gated potassium channel) cause long-QT syndrome type 2 (LQT2) because of prolonged cardiac repolarization. However, Kv11.1 is also present in pancreatic α and β cells and intestinal L and K cells, secreting glucagon, insulin, and the incretins glucagon-like peptide-1 (GLP-1) and GIP (glucose-dependent insulinotropic polypeptide), respectively. These hormones are crucial for glucose regulation, and long-QT syndrome may cause disturbed glucose regulation. We measured secretion of these hormones and cardiac repolarization in response to glucose ingestion in LQT2 patients with functional mutations in hERG and matched healthy participants, testing the hypothesis that LQT2 patients have increased incretin and β-cell function and decreased α-cell function, and thus lower glucose levels. Methods: Eleven patients with LQT2 and 22 sex-, age-, and body mass index–matched control participants underwent a 6-hour 75-g oral glucose tolerance test with ECG recording and blood sampling for measurements of glucose, insulin, C-peptide, glucagon, GLP-1, and GIP. Results: In comparison with matched control participants, LQT2 patients had 56% to 78% increased serum insulin, serum C-peptide, plasma GLP-1, and plasma GIP responses (P=0.03–0.001) and decreased plasma glucose levels after glucose ingestion (P=0.02) with more symptoms of hypoglycemia (P=0.04). Sixty-three percent of LQT2 patients developed hypoglycemic plasma glucose levels (<70 mg/dL) versus 36% control participants (P=0.16), and 18% patients developed serious hypoglycemia (<50 mg/dL) versus none of the controls. LQT2 patients had defective glucagon responses to low glucose, P=0.008. β-Cell function (Insulin Secretion Sensitivity Index-2) was 2-fold higher in LQT2 patients than in controls (4398 [95% confidence interval, 2259–8562] versus 2156 [1961–3201], P=0.03). Pharmacological Kv11.1 blockade (dofetilide) in rats had similar effect

  6. Reisen im freien Fall - Teil 2: Das Zwillingsparadoxon aus dem Blickwinkel der ART

    NASA Astrophysics Data System (ADS)

    Sonne, Bernd; Weiß, Reinhard

    2013-07-01

    Nachdem wir uns mit den Prinzipien der ART und einigen Beispielen vertraut gemacht haben, kommen wir nun zur Berechnung des Zwillingsparadoxons aus Sicht des reisenden Zwillings. Dabei spielt das Äquivalenzprinzip eine große Rolle. Deshalb wird die Bewegungssituation noch einmal erläutert, diesmal aus Sicht von Katrin. Sie befindet sich in ihrem System S'in Ruhe. In ihrem System läuft die Zeit t'ab. Nach dem Start fühlt Katrin jedoch eine Kraft, die sie als Gravitationskraft interpretieren kann. Sie merkt es daran, dass sie in den Sitz gedrückt wird. Nach einiger Zeit werden die Triebwerke abgeschaltet, und das Raumschiff fliegt mit konstanter Geschwindigkeit weiter, Phase 2. Anschließend wird der Schub der Triebwerke solange umgekehrt, bis das Raumschiff irgendwo mit der Geschwindigkeit null am Umkehrpunkt U landet, Phase 3 (Abb. 15.1). Die Erde, auf der sich Michael befindet, bewegt sich mit x'(t') aus Sicht von Katrin im freien Fall von ihr weg, s. das Experiment mit dem steigenden Fahrstuhl in Abschn. 13.2.1.

  7. Evolution of ionospheric convection and ULFs during the 27 March 2017 storm: ERG-SuperDARN campaign

    NASA Astrophysics Data System (ADS)

    Hori, T.; Nishitani, N.; Shepherd, S. G.; Ruohoniemi, J. M.; Connors, M. G.; Teramoto, M.; Nakano, S.; Seki, K.; Takahashi, N.; Kasahara, S.; Yokota, S.; Mitani, T.; Takashima, T.; Higashio, N.; Matsuoka, A.; Asamura, K.; Kazama, Y.; Wang, S. Y.; Tam, S. W. Y.; Miyoshi, Y.; Shinohara, I.

    2017-12-01

    The Exploration of energization and Radiation in Geospace (ERG) satellite, which was nicknamed "Arase" after its launch on late December, 2016, has successfully started regular observations recently. In concert with in situ measurement made by Arase in the inner magnetosphere, campaign observations with SuperDARN radars have been conducted with a special scan mode "interleaved_normalscan" since March, 2017. Some of the radars being operated in the special mode observed the dynamic evolution of ionospheric convection including superimposed ULF-like convection fluctuations with frequencies of mHz over the North American sector during a moderate magnetic storm on March 27, 2017. The large-scale evolution provided by the radar observations in the early morning sector shows that the ionospheric convection changed direction between westward and eastward several times in the course of the storm main phase. Some meso-scale patchy structures seen on 2-D profiles of the line-of-sight (LOS) velocity propagated both westward and eastward just after a major substorm intensification. Interestingly, the velocity fluctuations were accompanied by a drifting energetic electron population as observed by particle instruments onboard Arase. A simulation of the inner magnetosphere coupled with a global MHD simulation for this event reproduces intense particle injections in the premidnight sector, consistent with the energy dispersion of the observed drifting population. A detailed interpretation of the observations including those captured by Arase is discussed and compared with the simulation results.

  8. Magnetic phase diagram of ErGe 1-xSi x (0

    NASA Astrophysics Data System (ADS)

    Thuéry, P.; El Maziani, F.; Clin, M.; Schobinger-Papamantellos, P.; Buschow, K. H. J.

    1993-10-01

    The composition-temperature magnetic phase diagram of ErGe 1- xSi x (0 < x < 1) has been deduced from the powder neutron diffraction investigation of the magnetic structure of several samples in the 1.5-15 K range. These compounds present an antiferromagnetic behaviour with 7.2 < TN < 11.5 K. Four magnetic phases are present: two that are commensurate with the crystal lattice (wavevectors (1/2,0,1/2) and (0,0,1/2) and two incommensurate (wavevectors (0,0, kz and ( k' x,0, k' z) with a slight deviation of kx, k' x and k' z from 1/2). Whatever x, an incommensurate phase appears below TN, the wavevector being (0,0, kz) for x < 0.40 and ( k' x,0, k' z) for x > 0.40. For 0.17 ≥ x ≤ 0.55, a first-order transition occurs as function of the temperature between these two phases. For x ≥ 0.65, a lock-in transition takes place at TIC, leading from the wavevector ( k' x,0, k' z) to (1/2,0,1/2), as was already observed in ErSi. Finally, for x < 0.17 or 0.55 < x < 0.65, the wavevectors of the incommensurate phases characterized by (0,0, kz) or ( k' x,0, k' z) respectively remain unchanged in the whole temperature range below TN. For x≥0.65, a small amount of a magnetic phase characterized by the wavevector (0,0, 1/2) coexists with the main phases, below a Néel temperature T' N slightly lower than TN. In all cases, the erbium magnetic moments are colinear along the orthorhombic α-axis; the arrangement of the moments in the commensurate phases is the same as in ErSi and the incommensurate orderings correspond to sine-wave amplitude modulations. A brief account on the theoretical interpretation of this phase diagram is finally given.

  9. Discovery of 5-Chloro-1-(5-chloro-2-(methylsulfonyl)benzyl)-2-imino-1,2-dihydropyridine-3-carboxamide (TAK-259) as a Novel, Selective, and Orally Active α1D Adrenoceptor Antagonist with Antiurinary Frequency Effects: Reducing Human Ether-a-go-go-Related Gene (hERG) Liabilities.

    PubMed

    Sakauchi, Nobuki; Kohara, Yasuhisa; Sato, Ayumu; Suzaki, Tomohiko; Imai, Yumi; Okabe, Yuichi; Imai, Shigemitsu; Saikawa, Reiko; Nagabukuro, Hiroshi; Kuno, Haruhiko; Fujita, Hisashi; Kamo, Izumi; Yoshida, Masato

    2016-04-14

    A novel structural class of iminopyridine derivative 1 was identified as a potent and selective human α1D adrenoceptor (α1D adrenergic receptor; α1D-AR) antagonist against α1A- and α1B-AR through screening of an in-house compound library. From initial structure-activity relationship studies, we found lead compound 9m with hERG K(+) channel liability. To develop analogues with reduced hERG K(+) channel inhibition, a combination of site-directed mutagenesis and docking studies was employed. Further optimization led to the discovery of (R)-9s and 9u, which showed antagonistic activity by a bladder strip test in rats with bladder outlet obstruction, as well as ameliorated cystitis-induced urinary frequency in rats. Ultimately, 9u was selected as a clinical candidate. This is the first study to show the utility of iminopyridine derivatives as selective α1D-AR antagonists and evaluate their effects in vivo.

  10. Detection of Gene Rearrangements in Circulating Tumor Cells: Examples of ALK-, ROS1-, RET-Rearrangements in Non-Small-Cell Lung Cancer and ERG-Rearrangements in Prostate Cancer.

    PubMed

    Catelain, Cyril; Pailler, Emma; Oulhen, Marianne; Faugeroux, Vincent; Pommier, Anne-Laure; Farace, Françoise

    2017-01-01

    Circulating tumor cells (CTCs) hold promise as biomarkers to aid in patient treatment stratification and disease monitoring. Because the number of cells is a critical parameter for exploiting CTCs for predictive biomarker's detection, we developed a FISH (fluorescent in situ hybridization) method for CTCs enriched on filters (filter-adapted FISH [FA-FISH]) that was optimized for high cell recovery. To increase the feasibility and reliability of the analyses, we combined fluorescent staining and FA-FISH and developed a semi-automated microscopy method for optimal FISH signal identification in filtration-enriched CTCs . Here we present these methods and their use for the detection and characterization of ALK-, ROS1-, RET-rearrangement in CTCs from non-small-cell lung cancer and ERG-rearrangements in CTCs from prostate cancer patients.

  11. Medium-Energy Particle experiments (MEPs) for the Exploration of energization and Radiation in Geospace (ERG) mission

    NASA Astrophysics Data System (ADS)

    Kasahara, S.; Yokota, S.; Mitani, T.; Asamura, K.; Hirahara, M.; Shibano, Y.; Yamamoto, K.; Takashima, T.

    2017-12-01

    ERG (Exploration of energization and Radiation in Geospace) is the geospace exploration spacecraft, which was launched on 20 December 2016. The mission goal is to unveil the physics behind the drastic radiation belt variability during space storms. One of key observations is the measurement of ions and electrons in the medium-energy range (10-200 keV), since these particles excite EMIC, magnetosonic, and whistler waves, which are theoretically suggested to play significant roles in the relativistic electron acceleration and loss. Medium-Energy Particle experiments - electron analyser (MEP-e) measures the energy and the direction of each incoming electron in the range of 7 to 87 keV. The sensor covers 2π radian disk-like field-of-view with 16 detectors, and the solid angle coverage is achieved by using spacecraft spin motion. The electron energy is independently measured by an electrostatic analyser and avalanche photodiodes, enabling the significant background reduction. Medium-Energy Particle experiments - ion mass analyzer (MEP-i) measures the energy, mass, and charge state of the direction of each incoming ion in the medium-energy range (<10 to >180 keV/q). MEP-i thus provides the velocity distribution functions of medium-energy ions (e.g., protons and oxygens), from which we can obtain significant information on local ion energization and pitch angle scattering in the inner magnetosphere. Heavy ion measurements can also play an important role to restrict global mass transport including the ionosphere and the plasmasheet. Here we show the technical approaches, data output, and highlights of initial observations.

  12. Two missense mutations, E123Q and K151E, identified in the ERG11 allele of an azole-resistant isolate of Candida kefyr recovered from a stem cell transplant patient for acute myeloid leukemia.

    PubMed

    Couzigou, Célia; Gabriel, Frédéric; Biteau, Nicolas; Fitton-Ouhabi, Valérie; Noël, Thierry; Accoceberry, Isabelle

    2014-07-01

    We report on the first cloning and nucleotide sequencing of an ERG11 allele from a clinical isolate of Candida kefyr cross-resistant to azole antifungals. It was recovered from a stem cell transplant patient, in an oncohematology unit exhibiting unexpected high prevalence of C. kefyr. Two amino acid substitutions were identified: K151E, whose role in fluconazole resistance was already demonstrated in Candida albicans, and E123Q, a new substitution never described so far in azole-resistant Candida yeast.

  13. Final scientific and technical report: New experiments to measure the neutrino mass scale

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Monreal, Benjamin

    In this work, we made material progress towards future measurements of the mass of the neutrino. The neutrino is a fundamental particle, first observed in the 1950s and subjected to particularly intense study over the past 20 years. It is now known to have some, non-zero mass, but we are in an unusual situation of knowing the mass exists but not knowing what value it takes. The mass may be determined by precise measurements of certain radioactive decay distributions, particularly the beta decay of tritium. The KATRIN experiment is an international project which is nearing the beginning of a tritiummore » measurement campaign using a large electrostatic spectrumeter. This research included participation in KATRIN, including construction and delivery of a key calibration subsystem, the ``Rear Section''. To obtain sensitivity beyond KATRIN's, new techniques are required; this work included R&D on a new technique we call CRES (Cyclotron Resonance Electron Spectroscopy) which has promise to enable even more sensitive tritium decay measurements. We successfully carried out CRES spectroscopy in a model system in 2014, making an important step towards the design of a next-generation tritium experiment with new neutrino mass measurement abilities.« less

  14. Two missense mutations, E123Q and K151E, identified in the ERG11 allele of an azole-resistant isolate of Candida kefyr recovered from a stem cell transplant patient for acute myeloid leukemia

    PubMed Central

    Couzigou, Célia; Gabriel, Frédéric; Biteau, Nicolas; Fitton-Ouhabi, Valérie; Noël, Thierry; Accoceberry, Isabelle

    2014-01-01

    We report on the first cloning and nucleotide sequencing of an ERG11 allele from a clinical isolate of Candida kefyr cross-resistant to azole antifungals. It was recovered from a stem cell transplant patient, in an oncohematology unit exhibiting unexpected high prevalence of C. kefyr. Two amino acid substitutions were identified: K151E, whose role in fluconazole resistance was already demonstrated in Candida albicans, and E123Q, a new substitution never described so far in azole-resistant Candida yeast. PMID:24936404

  15. Benchmarking the ERG valve tip and MRI Interventions Smart Flow neurocatheter convection-enhanced delivery system's performance in a gel model of the brain: employing infusion protocols proposed for gene therapy for Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Sillay, Karl; Schomberg, Dominic; Hinchman, Angelica; Kumbier, Lauren; Ross, Chris; Kubota, Ken; Brodsky, Ethan; Miranpuri, Gurwattan

    2012-04-01

    Convection-enhanced delivery (CED) is an advanced infusion technique used to deliver therapeutic agents into the brain. CED has shown promise in recent clinical trials. Independent verification of published parameters is warranted with benchmark testing of published parameters in applicable models such as gel phantoms, ex vivo tissue and in vivo non-human animal models to effectively inform planned and future clinical therapies. In the current study, specific performance characteristics of two CED infusion catheter systems, such as backflow, infusion cloud morphology, volume of distribution (mm3) versus the infused volume (mm3) (Vd/Vi) ratios, rate of infusion (µl min-1) and pressure (mmHg), were examined to ensure published performance standards for the ERG valve-tip (VT) catheter. We tested the hypothesis that the ERG VT catheter with an infusion protocol of a steady 1 µl min-1 functionality is comparable to the newly FDA approved MRI Interventions Smart Flow (SF) catheter with the UCSF infusion protocol in an agarose gel model. In the gel phantom models, no significant difference was found in performance parameters between the VT and SF catheter. We report, for the first time, such benchmark characteristics in CED between these two otherwise similar single-end port VT with stylet and end-port non-stylet infusion systems. Results of the current study in agarose gel models suggest that the performance of the VT catheter is comparable to the SF catheter and warrants further investigation as a tool in the armamentarium of CED techniques for eventual clinical use and application.

  16. Development of Electric Field and Plasma Wave Investigations for Future Space Weather Missions: ERG, SCOPE, and beyond

    NASA Astrophysics Data System (ADS)

    Kasaba, Y.; Kumamoto, A.; Ono, T.; Misawa, H.; Kojima, H.; Yagitani, S.; Kasahara, Y.; Ishisaka, K.

    2009-04-01

    The electric field and plasma wave investigation is important for the clarification of global plasma dynamics and energetic processes in the planetary Magnetospheric studies. We have several missions which will contribute those objectives. the small-sized radiation belt mission, ERG (Energization and Radiation in Geospace), the cross-scale formation flight mission, SCOPE, the BepiColombo mission to Mercury, and the small-sized and full-scale Jovian mission in future. Those will prevail the universal plasma mechanism and processes in the space laboratory. The main purposes of electric field and plasma wave observation for those missions are: (1) Examination of the theories of high-energy particle acceleration by plasma waves, (2) identification of the origin of electric fields in the magnetosphere associated with cross-scale coupling processes, (3) diagnosis of plasma density, temperature and composition, and (4) investigation of wave-particle interaction and mode conversion processes. Simultaneous observation of plasma waves and energetic particles with high resolution will enable us to investigate the wave-particle interaction based on quasi-linear theory and non-linear models. In this paper, we will summarize the current plan and efforts for those future activities. In order to achieve those objectives, the instrument including sensitive sensors (the long wire / stem antennae, the search-coil / loop antennae) and integrated receiver systems are now in development, including the direct identification of nonlinear wave-particle interactions associated will be tried by Wave-particle Correlator. And, as applications of those development, we will mention to the space interferometer and the radar sounder technologies.

  17. Identifying events with prominent fluctuations common to particle and wave observations by the ERG/Arase satellite

    NASA Astrophysics Data System (ADS)

    Chiang, C. Y.; Tam, S. W. Y.; Chang, T. F.; Syugu, W. J.; Kazama, Y.; Wang, S. Y.; Wang, B. J.; Asamura, K.; Higashio, N.; Kasahara, S.; Kasahara, Y.; Matsuoka, A.; Mitani, T.; Yokota, S.; Miyoshi, Y.; Shinohara, I.

    2017-12-01

    The Energization and Radiation in Geospace (ERG) satellite, launched in December 2016 and also known as "Arase" since then, began its regular observations of the inner magnetosphere in March 2017. On board the satellite are various instruments for the measurements of electrons and ions of various energy ranges, and electric and magnetic fields at various frequencies. The electron instruments include the Low-Energy Particle Experiments - Electron Analyzer (LEP-e), which performs measurements of electrons in the energy range between 20 eV and 19 keV, and three other experiments, Medium-Energy Particle Experiments - Electron Analyzer (MEP-e), High-Energy Electron Experiments (HEP) and Extremely High-Energy Electron Experiments (XEP), respectively covering the medium, high, and extremely high energy ranges up to 20 MeV. Ion measurements are performed by Low-Energy Particle Experiments - Ion Mass Analyzer (LEP-i) and Medium-Energy Particle Experiments - Ion Mass Analyzer (MEP-i) together for energies between 10 eV and 180 keV per unit charge, while the electric and magnetic fields are observed by Plasma Wave Experiment (PWE) and Magnetic Field Experiment (MGF).As LEP-e focuses on the lowest energy range among the electron sensors, it is expected to cover the largest electron population in the observations. Hence, significant variations in the LEP-e measurements are indicators of physical processes that affect a majority of electrons. Over several months, LEP-e has observed a number of events in which the measured electron counts exhibit prominent fluctuations at regular time scales. These events are examined also using measurements of the other aforementioned experiments, and it is found that similar prominent fluctuations are also observed by all of those instruments in quite a few events. In this presentation, we focus on such events and discuss the similarities and differences among them.

  18. Functional characterization of Kv11.1 (hERG) potassium channels split in the voltage-sensing domain.

    PubMed

    de la Peña, Pilar; Domínguez, Pedro; Barros, Francisco

    2018-03-23

    Voltage-dependent KCNH family potassium channel functionality can be reconstructed using non-covalently linked voltage-sensing domain (VSD) and pore modules (split channels). However, the necessity of a covalent continuity for channel function has not been evaluated at other points within the two functionally independent channel modules. We find here that by cutting Kv11.1 (hERG, KCNH2) channels at the different loops linking the transmembrane spans of the channel core, not only channels split at the S4-S5 linker level, but also those split at the intracellular S2-S3 and the extracellular S3-S4 loops, yield fully functional channel proteins. Our data indicate that albeit less markedly, channels split after residue 482 in the S2-S3 linker resemble the uncoupled gating phenotype of those split at the C-terminal end of the VSD S4 transmembrane segment. Channels split after residues 514 and 518 in the S3-S4 linker show gating characteristics similar to those of the continuous wild-type channel. However, breaking the covalent link at this level strongly accelerates the voltage-dependent accessibility of a membrane impermeable methanethiosulfonate reagent to an engineered cysteine at the N-terminal region of the S4 transmembrane helix. Thus, besides that of the S4-S5 linker, structural integrity of the intracellular S2-S3 linker seems to constitute an important factor for proper transduction of VSD rearrangements to opening and closing the cytoplasmic gate. Furthermore, our data suggest that the short and probably rigid characteristics of the extracellular S3-S4 linker are not an essential component of the Kv11.1 voltage sensing machinery.

  19. Autoimmune retinopathy with RPE hypersensitivity and 'negative ERG' in X-linked hyper-IgM syndrome.

    PubMed

    Schuster, Andreas; Apfelstedt-Sylla, Eckart; Pusch, Carsten M; Zrenner, Eberhart; Thirkill, Charles E

    2005-01-01

    To report the clinical, electrophysiological, and immunological features of a patient with X-linked hyper-IgM immunodeficiency syndrome type 1 (HIGM1) accompanied by a novel type of autoimmune retinopathy, including retinal pigment epithelium (RPE) hypersensitivity. Comprehensive ophthalmological examinations, electrophysiological function testing, and inquiries into the immunological status of a 13-year-old presenting with subacute loss of vision in association with a molecularly confirmed diagnosis of HIGM1 were performed. The patient was genotyped by a PCR-based sequence tag content mapping strategy to define the genetic defect within the causative X-HIM gene TNFSF5. Since conventional allogenic bone marrow transplantation has been reported to cure HIGM1, a peripheral blood stem-cell transplantation was performed. (1) The patient's reduced visual acuity included prolonged dark adaptation and visual field constriction. Electrophysiology revealed a 'negative ERG' indicating post-receptoral dysfunction. (2) Initial immunological examination of the patient's serum identified abnormal antibody activity with components of the photoreceptors and the inner nuclear layer. The patient later developed indications of RPE hypersensitivity. A massively reduced light-peak to dark-trough ratio of the EOG slow oscillations (L/D ratio) corresponded to impaired RPE-photoreceptor complex function. (3) Molecular genetic analyses revealed the patient to be nullizygous for the tumor necrosis factor ligand member 5 gene (TNFSF5; CD40LG). A large chromosomal deletion of approximately 27.6-32.3 kb in size was identified in Xq26. (4) The transplant with its associated immunomodulation appeared to worsen rather than improve the patient's condition. The fundus appearance and electrophysiological function testing revealed indications of atypical retinal degeneration. However, the clinical course and the serological findings were consistent with those of ocular autoimmunity involving both

  20. Modulation of hERG potassium channel gating normalizes action potential duration prolonged by dysfunctional KCNQ1 potassium channel

    PubMed Central

    Zhang, Hongkang; Zou, Beiyan; Yu, Haibo; Moretti, Alessandra; Wang, Xiaoying; Yan, Wei; Babcock, Joseph J.; Bellin, Milena; McManus, Owen B.; Tomaselli, Gordon; Nan, Fajun; Laugwitz, Karl-Ludwig; Li, Min

    2012-01-01

    Long QT syndrome (LQTS) is a genetic disease characterized by a prolonged QT interval in an electrocardiogram (ECG), leading to higher risk of sudden cardiac death. Among the 12 identified genes causal to heritable LQTS, ∼90% of affected individuals harbor mutations in either KCNQ1 or human ether-a-go-go related genes (hERG), which encode two repolarizing potassium currents known as IKs and IKr. The ability to quantitatively assess contributions of different current components is therefore important for investigating disease phenotypes and testing effectiveness of pharmacological modulation. Here we report a quantitative analysis by simulating cardiac action potentials of cultured human cardiomyocytes to match the experimental waveforms of both healthy control and LQT syndrome type 1 (LQT1) action potentials. The quantitative evaluation suggests that elevation of IKr by reducing voltage sensitivity of inactivation, not via slowing of deactivation, could more effectively restore normal QT duration if IKs is reduced. Using a unique specific chemical activator for IKr that has a primary effect of causing a right shift of V1/2 for inactivation, we then examined the duration changes of autonomous action potentials from differentiated human cardiomyocytes. Indeed, this activator causes dose-dependent shortening of the action potential durations and is able to normalize action potentials of cells of patients with LQT1. In contrast, an IKr chemical activator of primary effects in slowing channel deactivation was not effective in modulating action potential durations. Our studies provide both the theoretical basis and experimental support for compensatory normalization of action potential duration by a pharmacological agent. PMID:22745159

  1. [AML(M7) associated with t(16;21)(p11;q22) showing relapse after unrelated bone marrow transplantation and disappearance of TLS/FUS-ERG mRNA].

    PubMed

    Fukushima, Y; Fujii, N; Tabata, Y; Nishimura, Y; Fusaoka, T; Yoshihara, T; Tsunamoto, K; Kasubuchi, Y; Morimoto, A; Hibi, S; Taketani, K; Hayashi, Y; Imashuku, S

    2001-06-01

    A 3-year-old boy with poorly prognostic acute megakaryoblastic leukemia (AML M7) showing t(16;21)(p11;q22) karyotype underwent unrelated bone marrow transplantation (U-BMT) during his first hematological remission. The conditioning regimen consisted of BU, VP-16 and L-PAM. Engraftment was smooth, but the patient developed grade I acute GVHD. During hematological remission before U-BMT, the TLS/FUS-ERG chimeric transcript of t(16;21)(p11;q22) was consistently detectable as minimal residual disease (MRD) by RT-PCR. However, after U-BMT it soon became undetectable. There was no detectable MRD until 7 months after U-BMT, but bone marrow relapse occurred 10 months after U-BMT. We consider that U-BMT is a promising treatment for t(16;21)(p11;q22) AML. However, an intensified conditioning regimen or modification of GVHD prophylaxis is needed.

  2. Azimuthal Structure of the Sand Erg that Encircles the North Polar Water-Ice Cap

    NASA Astrophysics Data System (ADS)

    Teodoro, L. A.; Elphic, R. C.; Eke, V. R.; Feldman, W. C.; Maurice, S.; Pathare, A.

    2011-12-01

    The sand erg that completely encircles the perennial water-ice cap that covers the Martian north geographic pole displays considerable azimuthal structure as seen in visible and near-IR images. Much of this structure is associated with the terminations of the many steep troughs that cut spiral the approximately 3 km thick polar ice cap. Other contributions come from the katabatic winds that spill over steep-sided edges of the cap, such as what bounds the largest set of dunes that comprise Olympia Undae. During the spring and summer months when these winds initiate from the higher altitudes that contain sublimating CO2 ice, which is very cold and dry, heat adiabatically when they compress as they lose altitude. These winds should then remove H2O moisture from the uppermost layer of the sand dunes that are directly in their path. Two likely locations where this desiccation may occur preferentially is at the termination of Chasma Boreale and the ice cap at Olympia Undae. We will search for this effect by sharpening the spatial structure of the epithermal neutron counting rates measured at northern high latitudes using the Mars Odyssey Neutron Spectrometer (MONS). The epithermal range of neutron energies is nearly uniquely sensitive to the hydrogen content of surface soils, which should likely be in the form of H2O/OH molecules/radicals. We therefore convert epithermal counting rates in terms of Water-Equivalent-Hydrogen, WEH. However, MONS counting-rate data have a FWHM of ~550 km., which is sufficiently broad to prevent a close association of WEH variability with images of geological features. In this study, we reduce spurious features in the instrument smeared neutron counting rates through deconvolution. We choose the PIXON numerical deconvolution technique for this purpose. This technique uses a statistical approach (Pina 2001, Eke 2001), which is capable of removing spurious features in the data in the presence of noise. We have previously carried out a detailed

  3. The magnetic field investigation on the ARASE (ERG) mission: Data characteristics and initial scientific results

    NASA Astrophysics Data System (ADS)

    Matsuoka, A.; Teramoto, M.; Nomura, R.; Nose, M.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Nagatsuma, T.; Shiokawa, K.; Obana, Y.; Miyoshi, Y.; Takashima, T.; Shinohara, I.

    2017-12-01

    The ARASE (ERG) satellite was successfully launched on December 20 2016. A fluxgate magnetometer (MGF) was built for the ARASE satellite to measure DC and low-frequency magnetic field. The requirements to the magnetic field measurements by ARASE was defined as (1) accuracy of the absolute field intensity is within 5 nT (2) angular accuracy of the field direction is within 1 degree (3) measurement frequency range is from DC to 60Hz or wider. MGF measures the vector magnetic field with the original sampling frequency of 256 Hz. The dynamic range is switched between +/-8000nT and +/- 60000nT according to the background field intensity. The MGF initial checkout was carried on January 10th 2017, when the MGF normal performance and downlinked data were confirmed. The 5-m length MAST for the sensor was deployed on 17th January. The nominal operation of MGF started in March 2017. The MGF data are calibrated based on the results from the ground experiments and in-orbit data analysis. The MGF CDF files are distributed by the ARASE Science Center and available by Space Physics Environment Data Analysis Software (SPEDAS). The acceleration process of the charged particles in the inner magnetosphere is considered to be closely related to the deformation and perturbation of the magnetic field. Accurate measurement of the magnetic field is required to understand the acceleration mechanism of the charged particles, which is one of the major scientific objectives of the ARASE mission. We designed a fluxgate magnetometer which is optimized to investigate following topics; (1) accurate measurement of the background magnetic field - the deformation of the magnetic field and its relationship with the particle acceleration. (2) MHD waves - measurement of the ULF electromagnetic waves of frequencies about 1mHz (Pc4-5), and investigation of the radiation-belt electrons radially diffused by the resonance with the ULF waves. (3) EMIC waves - measurement of the electromagnetic ion

  4. hERG1/Kv11.1 activation stimulates transcription of p21waf/cip in breast cancer cells via a calcineurin-dependent mechanism.

    PubMed

    Perez-Neut, Mathew; Rao, Vidhya R; Gentile, Saverio

    2016-09-13

    The function of Kv11.1 is emerging in breast cancer biology, as a growing body of evidence indicates that the hERG1/Kv11.1 potassium channel is aberrantly expressed in several cancer types including breast cancers.The biological effects of Kv11.1 channel blockers and their associated side effects are very well known but the potential use of Kv11.1 activators as an anticancer strategy are still unexplored. In our previous work, we have established that stimulation of the Kv11.1 potassium channel activates a senescent-like program that is characterized by a significant increase in tumor suppressor protein levels, such as p21waf/cip and p16INK4A. In this study we investigated the mechanism linking Kv11.1 stimulation to augmentation of p21waf/cip protein level. We have demonstrated that the Kv11.1 channel activator NS1643 activates a calcineurin-dependent transcription of p21waf/cip and that this event is fundamental for the inhibitory effect of NS1643 on cell proliferation. Our results reveal a novel mechanism by which stimulation of Kv11.1 channel leads to transcription of a potent tumor suppressor and suggest a potential therapeutic use for Kv11.1 channel activators.

  5. hERG1/Kv11.1 activation stimulates transcription of p21waf/cip in breast cancer cells via a calcineurin-dependent mechanism

    PubMed Central

    Perez-Neut, Mathew; Rao, Vidhya R.; Gentile, Saverio

    2016-01-01

    The function of Kv11.1 is emerging in breast cancer biology, as a growing body of evidence indicates that the hERG1/Kv11.1 potassium channel is aberrantly expressed in several cancer types including breast cancers. The biological effects of Kv11.1 channel blockers and their associated side effects are very well known but the potential use of Kv11.1 activators as an anticancer strategy are still unexplored. In our previous work, we have established that stimulation of the Kv11.1 potassium channel activates a senescent-like program that is characterized by a significant increase in tumor suppressor protein levels, such as p21waf/cip and p16INK4A. In this study we investigated the mechanism linking Kv11.1 stimulation to augmentation of p21waf/cip protein level. We have demonstrated that the Kv11.1 channel activator NS1643 activates a calcineurin-dependent transcription of p21waf/cip and that this event is fundamental for the inhibitory effect of NS1643 on cell proliferation. Our results reveal a novel mechanism by which stimulation of Kv11.1 channel leads to transcription of a potent tumor suppressor and suggest a potential therapeutic use for Kv11.1 channel activators. PMID:25945833

  6. Multifocal electroretinogram contributes to differentiation of various clinical pictures within a family with Bardet-Biedl syndrome.

    PubMed

    Praidou, A; Hagan, R; Nayak, H; Chandna, A

    2014-09-01

    To demonstrate the use of the multifocal electroretinogram (mfERG) in addition to the full-field electroretinogram (ERG) in defining varying clinical pictures in children within a family with Bardet-Biedl syndrome (BBS). All members from a family generation underwent a detailed history and examination before proceeding to a detailed ERG in accordance with the International Society of Clinical Electrophysiology for Vision protocol and a rapid, low-resolution mfERG. Of the sibling pair, the 13-year-old boy showed reduced vision and atypical maculopathy and the 10-year-old sister showed normal vision and atrophic maculopathy. Parents had normal ocular examination. The male sibling had reduced rod and cone full-field ERG responses with a relatively spared central response from the mfERG suggesting central macular sparing. In contrast, for the female sibling, the ERG was normal for the cone pathway although reduced for rod pathway, with mfERG showing central involvement. The mother had rod responses at the lower end of normal range, a normal cone pathway, and a normal mfERG. The father showed a normal ERG and mfERG. The mfERG is a useful adjunct to full-field ERG in the paediatric population and in family studies.

  7. A GLIMPSE INTO THE EYE OF THE EMERGENCY RESPONSE AT EPA KATRINA AND RITA

    EPA Science Inventory

    This presentation was given at the Texas Environmental Health Association Annual Meeting in Round Rock, TX on October 12, 2005. The keynote address was focused on the conditions after Katrins, organizing response, field response, EPA's role in emergency response, what is EPA doi...

  8. Gating mechanism of Kv11.1 (hERG) K+ channels without covalent connection between voltage sensor and pore domains.

    PubMed

    de la Peña, Pilar; Domínguez, Pedro; Barros, Francisco

    2018-03-01

    Kv11.1 (hERG, KCNH2) is a voltage-gated potassium channel crucial in setting the cardiac rhythm and the electrical behaviour of several non-cardiac cell types. Voltage-dependent gating of Kv11.1 can be reconstructed from non-covalently linked voltage sensing and pore modules (split channels), challenging classical views of voltage-dependent channel activation based on a S4-S5 linker acting as a rigid mechanical lever to open the gate. Progressive displacement of the split position from the end to the beginning of the S4-S5 linker induces an increasing negative shift in activation voltage dependence, a reduced z g value and a more negative ΔG 0 for current activation, an almost complete abolition of the activation time course sigmoid shape and a slowing of the voltage-dependent deactivation. Channels disconnected at the S4-S5 linker near the S4 helix show a destabilization of the closed state(s). Furthermore, the isochronal ion current mode shift magnitude is clearly reduced in the different splits. Interestingly, the progressive modifications of voltage dependence activation gating by changing the split position are accompanied by a shift in the voltage-dependent availability to a methanethiosulfonate reagent of a Cys introduced at the upper S4 helix. Our data demonstrate for the first time that alterations in the covalent connection between the voltage sensor and the pore domains impact on the structural reorganizations of the voltage sensor domain. Also, they support the hypothesis that the S4-S5 linker integrates signals coming from other cytoplasmic domains that constitute either an important component or a crucial regulator of the gating machinery in Kv11.1 and other KCNH channels.

  9. Multifocal electroretinograms.

    PubMed

    Creel, Donnell J

    2011-12-04

    A limitation of traditional full-field electroretinograms (ERG) for the diagnosis of retinopathy is lack of sensitivity. Generally, ERG results are normal unless more than approximately 20% of the retina is affected. In practical terms, a patient might be legally blind as a result of macular degeneration or other scotomas and still appear normal, according to traditional full field ERG. An important development in ERGs is the multifocal ERG (mfERG). Erich Sutter adapted the mathematical sequences called binary m-sequences enabling the isolation from a single electrical signal an electroretinogram representing less than each square millimeter of retina in response to a visual stimulus. Results that are generated by mfERG appear similar to those generated by flash ERG. In contrast to flash ERG, which best generates data appropriate for whole-eye disorders. The basic mfERG result is based on the calculated mathematical average of an approximation of the positive deflection component of traditional ERG response, known as the b-wave. Multifocal ERG programs measure electrical activity from more than a hundred retinal areas per eye, in a few minutes. The enhanced spatial resolution enables scotomas and retinal dysfunction to be mapped and quantified. In the protocol below, we describe the recording of mfERGs using a bipolar speculum contact lens. Components of mfERG systems vary between manufacturers. For the presentation of visible stimulus, some suitable CRT monitors are available but most systems have adopted the use of flat-panel liquid crystal displays (LCD). The visual stimuli depicted here, were produced by a LCD microdisplay subtending 35-40 degrees horizontally and 30-35 degrees vertically of visual field, and calibrated to produce multifocal flash intensities of 2.7 cd s m(-2). Amplification was 50K. Lower and upper bandpass limits were 10 and 300 Hz. The software packages used were VERIS versions 5 and 6.

  10. A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram

    PubMed Central

    Zele, Andrew J.; Kambhampati, Pradeep K.; Aher, Avinash; McKeefry, Declan; Parry, Neil; Maguire, John; Murray, Ian

    2017-01-01

    Purpose We introduce a method for determining the impulse response function (IRF) of the ERG derived from responses to temporal white noise (TWN) stimuli. Methods This white noise ERG (wnERG) was recorded in participants with normal trichromatic vision to full-field (Ganzfeld) and 39.3° diameter focal stimuli at mesopic and photopic mean luminances and at different TWN contrasts. The IRF was obtained by cross-correlating the TWN stimulus with the wnERG. Results We show that wnERG recordings are highly repeatable, with good signal-to-noise ratio, and do not lead to blink artifacts. The wnERG resembles a flash ERG waveform with an initial negativity (N1) followed by a positivity (P1), with amplitudes that are linearly related to stimulus contrast. These N1 and N1-P1 components showed commonalties in implicit times with the a- and b-waves of flash ERGs. There was a clear transition from rod- to cone-driven wnERGs at ∼1 photopic cd.m−2. We infer that oscillatory potentials found with the flash ERG, but not the wnERG, may reflect retinal nonlinearities due to the compression of energy into a short time period during a stimulus flash. Conclusion The wnERG provides a new approach to study the physiology of the retina using a stimulation method with adaptation and contrast conditions similar to natural scenes to allow for independent variation of stimulus strength and mean luminance, which is not possible with the conventional flash ERG. Translational Relevance The white noise ERG methodology will be of benefit for clinical studies and animal models in the evaluation of hypotheses related to cellular redundancy to understand the effects of disease on specific visual pathways. PMID:29109907

  11. Ergothioneine Is a Secreted Antioxidant in Mycobacterium smegmatis

    PubMed Central

    Williams, Monique J.; Wiid, Ian J.; Hiten, Nicholas F.; Viljoen, Albertus J.; Pietersen, Ray-Dean D.; van Helden, Paul D.

    2013-01-01

    Ergothioneine (ERG) and mycothiol (MSH) are two low-molecular-weight thiols synthesized by mycobacteria. The role of MSH has been extensively investigated in mycobacteria; however, little is known about the role of ERG in mycobacterial physiology. In this study, quantification of ERG at various points in the growth cycle of Mycobacterium smegmatis revealed that a significant portion of ERG is found in the culture media, suggesting that it is actively secreted. A mutant of M. smegmatis lacking egtD (MSMEG_6247) was unable to synthesize ERG, confirming its role in ERG biosynthesis. Deletion of egtD from wild-type M. smegmatis and an MSH-deficient mutant did not affect their susceptibility to antibiotics tested in this study. The ERG- and MSH-deficient double mutant was significantly more sensitive to peroxide than either of the single mutants lacking either ERG or MSH, suggesting that both thiols play a role in protecting M. smegmatis against oxidative stress and that ERG is able to partly compensate for the loss of MSH. PMID:23629716

  12. Africa’s Evolving Infosystems: A Pathway to Security and Stability

    DTIC Science & Technology

    2011-03-01

    Another problem involved the development of a missing persons identification system to be deployed in the aftermath of a hurricane or other...Activism in Africa (Cape Town: Pamba- zuka Press, 2010). 26 Sheila Kinkade and Katrin Verclas, Wireless Technology for Social Change (Wash- ington, DC: UN

  13. Kamstrupp's Wow-Effect: Re-Examined and Expanded

    ERIC Educational Resources Information Center

    King, Elizabeth M.; Dickmann, Ellyn M.; Johnson, Barbara Z.

    2016-01-01

    This review examines Anne Katrine Kamstrupp's article "The wow-effect in science teacher education; technology; sociomateriality." In the discussion below we explore three key areas of her ethnographic research. First, we reconsider Kamstrupp's article through the lens of technology as a pedagogical choice and philosophy. This is…

  14. Calpain activation by ROS mediates human ether-a-go-go-related gene protein degradation by intermittent hypoxia.

    PubMed

    Wang, N; Kang, H S; Ahmmed, G; Khan, S A; Makarenko, V V; Prabhakar, N R; Nanduri, J

    2016-03-01

    Human ether-a-go-go-related gene (hERG) channels conduct delayed rectifier K(+) current. However, little information is available on physiological situations affecting hERG channel protein and function. In the present study we examined the effects of intermittent hypoxia (IH), which is a hallmark manifestation of sleep apnea, on hERG channel protein and function. Experiments were performed on SH-SY5Y neuroblastoma cells, which express hERG protein. Cells were exposed to IH consisting of alternating cycles of 30 s of hypoxia (1.5% O2) and 5 min of 20% O2. IH decreased hERG protein expression in a stimulus-dependent manner. A similar reduction in hERG protein was also seen in adrenal medullary chromaffin cells from IH-exposed neonatal rats. The decreased hERG protein was associated with attenuated hERG K(+) current. IH-evoked hERG protein degradation was not due to reduced transcription or increased proteosome/lysomal degradation. Rather it was mediated by calcium-activated calpain proteases. Both COOH- and NH2-terminal sequences of the hERG protein were the targets of calpain-dependent degradation. IH increased reactive oxygen species (ROS) levels, intracellular Ca(2+) concentration ([Ca(2+)]i), calpain enzyme activity, and hERG protein degradation, and all these effects were prevented by manganese-(111)-tetrakis-(1-methyl-4-pyridyl)-porphyrin pentachloride, a membrane-permeable ROS scavenger. These results demonstrate that activation of calpains by ROS-dependent elevation of [Ca(2+)]i mediates hERG protein degradation by IH. Copyright © 2016 the American Physiological Society.

  15. Gaseous 83mKr generator of monoenergetic electrons based on 83Rb deposited in zeolite

    NASA Astrophysics Data System (ADS)

    Sentkerestiová, J.; Vénos, D.; Slezák, M.

    2017-09-01

    The gaseous 83mKr electron source is currently used in neutrino mass experiments KATRIN and Project 8, dark matter experiments XENON, LUX and DarkSide, and ALICE (CERN) experiment. The main attractive features of this radioactive noble gas are its monoenergetic conversion electrons with well known energies and a half-life of 1.8 h, which is short enough to avoid any long-lasting contamination of the system. The long half-life of the mother 83Rb isotope (T1/2 = 86.2 d) enables more time demanding measurement. Particularly, in the neutrino mass experiments with gaseous tritium in which the 83mKr is applied in the same manner as the tritium, the K-32 conversion electrons with energy conveniently close to the beta spectrum endpoint represent an important test and calibration tool. Here, the design and characteristics of the gaseous 83mKr generator, including the 83mKr source itself, for KATRIN (KArlsruhe TRItium Neutrino) experiment are presented.

  16. Cone responses in Usher syndrome types 1 and 2 by microvolt electroretinography.

    PubMed

    Zein, Wadih M; Falsini, Benedetto; Tsilou, Ekaterina T; Turriff, Amy E; Schultz, Julie M; Friedman, Thomas B; Brewer, Carmen C; Zalewski, Christopher K; King, Kelly A; Muskett, Julie A; Rehman, Atteeq U; Morell, Robert J; Griffith, Andrew J; Sieving, Paul A

    2014-11-25

    Progressive decline of psychophysical cone-mediated measures has been reported in type 1 (USH1) and type 2 (USH2) Usher syndrome. Conventional cone electroretinogram (ERG) responses in USH demonstrate poor signal-to-noise ratio. We evaluated cone signals in USH1 and USH2 by recording microvolt level cycle-by-cycle (CxC) ERG. Responses of molecularly genotyped USH1 (n = 18) and USH2 (n = 24) subjects (age range, 15-69 years) were compared with those of controls (n = 12). A subset of USH1 (n = 9) and USH2 (n = 9) subjects was examined two to four times over 2 to 8 years. Photopic CxC ERG and conventional 30-Hz flicker ERG were recorded on the same visits. Usher syndrome subjects showed considerable cone flicker ERG amplitude losses and timing phase delays (P < 0.01) compared with controls. USH1 and USH2 had similar rates of progressive logarithmic ERG amplitude decline with disease duration (-0.012 log μV/y). Of interest, ERG phase delays did not progress over time. Two USH1C subjects retained normal response timing despite reduced amplitudes. The CxC ERG method provided reliable responses in all subjects, whereas conventional ERG was undetectable in 7 of 42 subjects. Cycle-by-cycle ERG showed progressive loss of amplitude in both USH1 and USH2 subjects, comparable to that reported with psychophysical measures. Usher subjects showed abnormal ERG response latency, but this changed less than amplitude with time. In USH syndrome, CxC ERG is more sensitive than conventional ERG and warrants consideration as an outcome measure in USH treatment trials. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  17. Evaluation of Hydroxychloroquine Retinopathy With Multifocal Electroretinography

    PubMed Central

    So, Scott C.; Hedges, Thomas R.; Schuman, Joel S.; Quireza, Maria Luz Amaro

    2007-01-01

    BACKGROUND AND OBJECTIVE To describe the changes revealed by multifocal electroretinography (ERG) in patients taking hydroxychloroquine. PATIENTS AND METHODS Six patients being treated for various inflammatory conditions with hydroxychloroquine for periods ranging from 8 months to 7 years were consecutively evaluated. Each examination included measurement of Snellen visual acuities, Amsler grid assessment, and automated visual field testing. In some cases, funduscopic examinations were complimented by photography and fluorescein angiography. Multifocal ERG was performed for all patients. RESULTS Three patients (six eyes) were found to have distinctive abnormalities on multifocal ERG consisting of pericentral depression of ERG signals. The abnormalities on multifocal ERG corresponded with the patients’ subjective descriptions and the visual field depiction of their pericentral scotomas. All affected patients had been taking hydroxychloroquine for at least 7 years. One patient with generalized depression on multifocal ERG had possible hydroxychloroquine retinopathy. Two patients (three eyes) had relatively normal results on multifocal ERG. CONCLUSION Multifocal ERG objectively demonstrates depression of signals in the perifoveal region in visually symptomatic patients with long-term hydroxychloroquine use. Even patients with normal visual acuity and no fundus abnormalities can have abnormal results. Although we have not yet identified patients with abnormalities on multifocal ERG before the onset of symptoms, multifocal ERG may be useful in monitoring patients at risk and may provide an earlier opportunity to identify maculopathy. PMID:12757106

  18. Novel 473-bp deletion in XLRS1 gene in a Japanese family with X-linked juvenile retinoschisis.

    PubMed

    Shinoda, Kei; Ohde, Hisao; Ishida, Susumu; Inoue, Makoto; Oguchi, Yoshihisa; Mashima, Yukihiko

    2004-07-01

    To present the clinical features of two brothers with molecularly confirmed X-linked juvenile retinoschisis (xlRS) but with non-characteristic electrophysiological findings. Comprehensive ophthalmological examinations were performed. The electroretinograms (ERGs) were recorded under ISCEV standards, and ERGs elicited by long-duration stimuli were also evaluated. Standard genetic analysis of peripheral blood leukocytes was performed. Molecular testing revealed a novel 473-bp deletion including exon 4 in the XLRS1 gene in both siblings. This resulted in a frameshift mutation and a premature termination at codon 78. The scotopic and photopic ERGs were reduced, but the "negative-type" ERG, characteristic of xlRS, was not observed. Flicker ERGs were also highly reduced. Long-duration stimuli elicited ERGs with a complete loss of the b-wave and a preservation of the off-response, i.e., negative-type ERG. The phenotype/genotype relationship was not determined. The consistency of the ERGs elicited by long-duration stimuli in xlRS patients suggests that this type of stimuli provides responses that are a better indicator for the progression or stage of the disease.

  19. Trichodiene Production in a Trichoderma harzianum erg1-Silenced Strain Provides Evidence of the Importance of the Sterol Biosynthetic Pathway in Inducing Plant Defense-Related Gene Expression.

    PubMed

    Malmierca, M G; McCormick, S P; Cardoza, R E; Monte, E; Alexander, N J; Gutiérrez, S

    2015-11-01

    Trichoderma species are often used as biocontrol agents against plant-pathogenic fungi. A complex molecular interaction occurs among the biocontrol agent, the antagonistic fungus, and the plant. Terpenes and sterols produced by the biocontrol fungus have been found to affect gene expression in both the antagonistic fungus and the plant. The terpene trichodiene (TD) elicits the expression of genes related to tomato defense and to Botrytis virulence. We show here that TD itself is able to induce the expression of Botrytis genes involved in the synthesis of botrydial (BOT) and also induces terpene gene expression in Trichoderma spp. The terpene ergosterol, in addition to its role as a structural component of the fungal cell membranes, acts as an elicitor of defense response in plants. In the present work, using a transformant of T. harzianum, which is silenced in the erg1 gene and accumulates high levels of squalene, we show that this ergosterol precursor also acts as an important elicitor molecule of tomato defense-related genes and induces Botrytis genes involved in BOT biosynthesis, in both cases, in a concentration-dependent manner. Our data emphasize the importance of a balance of squalene and ergosterol in fungal interactions as well as in the biocontrol activity of Trichoderma spp.

  20. Implantation and Recording of Wireless Electroretinogram and Visual Evoked Potential in Conscious Rats.

    PubMed

    Charng, Jason; He, Zheng; Bui, Bang; Vingrys, Algis; Ivarsson, Magnus; Fish, Rebecca; Gurrell, Rachel; Nguyen, Christine

    2016-06-29

    The full-field electroretinogram (ERG) and visual evoked potential (VEP) are useful tools to assess retinal and visual pathway integrity in both laboratory and clinical settings. Currently, preclinical ERG and VEP measurements are performed with anesthesia to ensure stable electrode placements. However, the very presence of anesthesia has been shown to contaminate normal physiological responses. To overcome these anesthesia confounds, we develop a novel platform to assay ERG and VEP in conscious rats. Electrodes are surgically implanted sub-conjunctivally on the eye to assay the ERG and epidurally over the visual cortex to measure the VEP. A range of amplitude and sensitivity/timing parameters are assayed for both the ERG and VEP at increasing luminous energies. The ERG and VEP signals are shown to be stable and repeatable for at least 4 weeks post surgical implantation. This ability to record ERG and VEP signals without anesthesia confounds in the preclinical setting should provide superior translation to clinical data.

  1. Lovastatin synergizes with itraconazole against planktonic cells and biofilms of Candida albicans through the regulation on ergosterol biosynthesis pathway.

    PubMed

    Zhou, Yujie; Yang, Hong; Zhou, Xuedong; Luo, Hongke; Tang, Fan; Yang, Jin; Alterovitz, Gil; Cheng, Lei; Ren, Biao

    2018-06-01

    The increase of fungal infectious diseases and lack of safe and efficacious antifungal drugs result in the urgent need of new therapeutic strategies. Here, we repurposed the lovastatin (LOV) as a synergistic antifungal potentiator to itraconazole (ITZ) against Candida albicans planktonic cells and biofilms in vitro for the first time. Mutants from ergosterol biosynthesis pathway were employed and key gene expression profiles of ergosterol pathway were also measured. LOV single treatment was unable to inhibit C. albicans strains except the ERG3 and ERG11 double mutant. LOV and ITZ combination was capable of inhibiting the C. albicans planktonic cells and biofilms synergistically including the ITZ resistant mutants. The synergistic antifungal ability was stronger in either ERG11 or ERG3 dysfunctional mutants compared to wild type. The combination lost the synergistic activities in the ERG11 and ERG3 double mutant, while it was sensitive to LOV single treatment. The expression of HMG1, encoding HMG-CoA the target of LOV, was significantly upregulated in ERG11 and ERG3 double mutant strain by the treatment of the combination at 1.5 and 3 h. The combination also significantly increased the HMG1 expression in mutants from ergosterol pathway compared with wild type. The ERG11 and ERG3 gene expressions were upregulated by ITZ and its combination with LOV, but seemingly not by LOV single treatment after 1.5 and 3 h. The combination of LOV and ITZ on C. albicans planktonic cells and biofilms highlights its potential clinical practice especially against the azole drug-resistant mutants.

  2. Loss of functional K+ channels encoded by ether-à-go-go-related genes in mouse myometrium prior to labour onset

    PubMed Central

    Greenwood, I A; Yeung, S Y; Tribe, R M; Ohya, S

    2009-01-01

    There is a growing appreciation that ion channels encoded by the ether-à-go-go-related gene family have a functional impact in smooth muscle in addition to their accepted role in cardiac myocytes and neurones. This study aimed to assess the expression of ERG1–3 (KCNH1–3) genes in the murine myometrium (smooth muscle layer of the uterus) and determine the functional impact of the ion channels encoded by these genes in pregnant and non-pregnant animals. Quantitative RT-PCR did not detect message for ERG2 and 3 in whole myometrial tissue extracts. In contrast, message for two isoforms of mERG1 were readily detected with mERG1a more abundant than mERG1b. In isometric tension studies of non-pregnant myometrium, the ERG channel blockers dofetilide (1 μm), E4031 (1 μm) and Be-KM1 (100 nm) increased spontaneous contractility and ERG activators (PD118057 and NS1643) inhibited spontaneous contractility. In contrast, neither ERG blockade nor activation had any effect on the inherent contractility in myometrium from late pregnant (19 days gestation) animals. Moreover, dofetilide-sensitive K+ currents with distinctive ‘hooked’ kinetics were considerably smaller in uterine myocytes from late pregnant compared to non-pregnant animals. Expression of mERG1 isoforms did not alter throughout gestation or upon delivery, but the expression of genes encoding auxillary subunits (KCNE) were up-regulated considerably. This study provides the first evidence for a regulation of ERG-encoded K+ channels as a precursor to late pregnancy physiological activity. PMID:19332483

  3. Time-Dependent Decline in Multifocal Electroretinogram Requires Faster Recording Procedures in Anesthetized Pigs

    PubMed Central

    Sørensen, Nina Buus; Christiansen, Anders Tolstrup; Kjær, Troels Wesenberg; Klemp, Kristian; la Cour, Morten; Kiilgaard, Jens Folke

    2017-01-01

    Purpose The time-dependent effect of anesthetics on the retinal function is debated. We hypothesize that in anesthetized animals there is a time-dependent decline that requires optimized multifocal electroretinogram (mfERG) recording procedures. Methods Conventional and four-frame global-flash mfERG recordings were obtained approximately 15, 60, and 150 minutes after the induction of propofol anesthesia (20 pigs) and isoflurane anesthesia (nine pigs). In six of the propofol-anesthetized pigs, the mfERG recordings were split in 3-minute segments. Two to 4 weeks after initial recordings, an intraocular injection of tetrodotoxin (TTX) was given and the mfERG was rerecorded as described above. Data were analyzed using mixed models in SAS statistical software. Results Propofol significantly decreases the conventional and global-flash amplitudes over time. The only significant effect of isoflurane is a decrease in the global-flash amplitudes. At 15 minutes after TTX injection several of the mfERG amplitudes are significantly decreased. There is a linear correlation between the conventional P1 and the global-flash DR mfERG-amplitude (R2 = 0.82, slope = 0.72, P < 0.0001). There is no significant difference between the 3-minute and the prolonged mfERG recordings for conventional amplitudes and the global-flash direct response. The global flash–induced component significantly decreases with prolonged mfERG recordings. Conclusions A 3-minute mfERG recording and a single stimulation protocol is sufficient in anesthetized pigs. Recordings should be obtained immediately after the induction of anesthesia. The effect of TTX is significant 15 minutes after injection, but is contaminated by the effect of anesthesia 90 minutes after injection. Therefore, the quality of mfERG recordings can be further improved by determining the necessary time-of-delay from intraocular injection of a drug to full effect. Translational Relevance General anesthesia is a possible source of error in mfERG

  4. The effect of topical anesthesia on the rat electroretinogram.

    PubMed

    Sandalon, Shai; Ofri, Ron

    2009-04-01

    Topical anesthetics are recommended when electroretinograms (ERGs) are recorded using contact lens electrodes. However, these drugs act by blocking voltage-gated Na+ channels. Since such channels have been located in both the inner and outer retina of many species, topical anesthesia could affect the ERG recordings in these subjects. The purpose of this study was to evaluate the effects of oxybuprocaine, a commonly used ester local anesthetic, on the rat ERG. Full-field scotopic and pattern ERGs (PERGs) were recorded successively from both eyes of seven rats. One eye was randomly treated with oxybuprocaine 15 min prior to recording. In 10 rats unilateral full-field photopic ERG recordings were conducted prior to, and 15 min after, treatment. B-wave amplitude ratios of the experimental/control eyes were 1.13, 1.30, and 1.35 for the three intensities used to record scotopic ERG responses, and 1.04 for the photopic ERG responses. PERG amplitude ratios of the experimental/control eyes were 1.10, 1.21, 1.21, 1.24, and 1.26 for the five patterns used. Treatment had no significant negative effect on signal amplitude or implicit time of the full-field ERG or PERG. In fact, amplitudes of signals from treated eyes tended to be (insignificantly) higher, though this might reflect better position of the active electrode rather than a biological effect. We conclude that oxybuprocaine has no negative effect on the rat ERG.

  5. The effects of fundus photography on the multifocal electroretinogram.

    PubMed

    Suresh, Sandip; Tienor, Brian J; Smith, Scott D; Lee, Michael S

    2016-02-01

    To determine the effect of flash fundus photography (FFP) on the multifocal electroretinogram (mfERG). Ten subjects underwent mfERG testing on three separate dates. Subjects received either mfERG without FFP, mfERG at 5 and 15 min after FFP, or mfERG at 30 and 45 min after FFP on each date. The FFP groups received 10 fundus photographs followed by mfERG testing, first of the right eye then of the left eye 10 min later. Data were averaged and analyzed in six concentric rings at each time point. Average amplitude and implicit times of the N1, P1, and N2 peaks for each concentric ring at each time point after FFP were compared to baseline. Flash fundus photography did not lead to a significant change of amplitude or implicit times of N1, P1, or N2 at 5 min after light exposure. These findings suggest that it is acceptable to perform mfERG testing without delay after performance of FFP.

  6. Abnormal dark-adapted electroretinogram in Best's vitelliform macular degeneration.

    PubMed

    Lachapelle, P; Quigley, M G; Polomeno, R C; Little, J M

    1988-10-01

    It is generally well accepted that in Best's vitelliform macular degeneration (BVMD) the electroretinogram (ERG) is normal whereas the electro-oculogram (EOG) is markedly abnormal. We describe a patient in whom BVMD was suspected on the basis of the clinical findings, EOG and family history (one of her daughters had the typical vitelliform lesion). However, her dark-adapted ERG was markedly abnormal. Similar anomalies were found in the dark-adapted ERG of the daughter. While the temporal features of the various ERG waves were well preserved, a substantial decrease in the amplitude of specific segments of the ERG signal was observed. A similar decrease in the amplitude of the oscillatory potentials was also found. We believe that this unusual combination of BVMD and abnormal dark-adapted ERG may be due to the reported reduced penetrance and variable expressivity of the BVMD gene(s).

  7. Effect of indocyanine green angiography using infrared fundus camera on subsequent dark adaptation and electroretinogram.

    PubMed

    Wen, Feng; Yu, Minzhong; Wu, Dezheng; Ma, Juanmei; Wu, Lezheng

    2002-07-01

    To observe the effect of indocyanine green angiography (ICGA) with infrared fundus camera on subsequent dark adaptation and the Ganzfeld electroretinogram (ERG), the ERGs of 38 eyes with different retinal diseases were recorded before and after ICGA during a 40-min dark adaptation period. ICGA was performed with Topcon 50IA retina camera. Ganzfeld ERG was recorded with Neuropack II evoked response recorder. The results showed that ICGA did not affect the latencies and the amplitudes in ERG of rod response, cone response and mixed maximum response (p>0.05). It suggests that ICGA using infrared fundus camera could be performed prior to the recording of the Ganzfeld ERG.

  8. Mitragynine and its potential blocking effects on specific cardiac potassium channels

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tay, Yea Lu; Teah, Yi Fan; Chong, Yoong Min

    2016-08-15

    Mitragyna speciosa Korth is known for its euphoric properties and is frequently used for recreational purposes. Several poisoning and fatal cases involving mitragynine have been reported but the underlying causes remain unclear. Human ether-a-go-go-related gene (hERG) encodes the cardiac I{sub Kr} current which is a determinant of the duration of ventricular action potentials and QT interval. On the other hand, I{sub K1}, a Kir current mediated by Kir2.1 channel and I{sub KACh}, a receptor-activated Kir current mediated by GIRK channel are also known to be important in maintaining the cardiac function. This study investigated the effects of mitragynine on themore » current, mRNA and protein expression of hERG channel in hERG-transfected HEK293 cells and Xenopus oocytes. The effects on Kir2.1 and GIRK channels currents were also determined in the oocytes. The hERG tail currents following depolarization pulses were inhibited by mitragynine with an IC{sub 50} value of 1.62 μM and 1.15 μM in the transfected cell line and Xenopus oocytes, respectively. The S6 point mutations of Y652A and F656A attenuated the inhibitor effects of mitragynine, indicating that mitragynine interacts with these high affinity drug-binding sites in the hERG channel pore cavity which was consistent with the molecular docking simulation. Interestingly, mitragynine does not affect the hERG expression at the transcriptional level but inhibits the protein expression. Mitragynine is also found to inhibit I{sub KACh} current with an IC{sub 50} value of 3.32 μM but has no significant effects on I{sub K1}. Blocking of both hERG and GIRK channels may cause additive cardiotoxicity risks. - Highlights: • The potential cardiac potassium channel blocking properties of mitragynine were investigated. • Mitragynine blocks hERG channel and I{sub Kr} in hERG-transfected HEK293 cells and hERG cRNA-injected Xenopus oocytes. • Mitragynine inhibits the hERG protein but not the mRNA expression.

  9. The multifocal electroretinogram in X-linked juvenile retinoschisis.

    PubMed

    Huang, Shizhou; Wu, Dezheng; Jiang, Futian; Luo, Guangwei; Liang, Jiongji; Wen, Feng; Yu, Minzhong; Long, Shixian; Wu, Lezheng

    2003-05-01

    To measure and compare the multifocal electroretinography in normal control and X-linked juvenile retinoschisis, 13 cases (13 right eyes) of normal control and nine cases (17 eyes) of X-linked juvenile retinoschisis were measured with VERIS Science 4.0. Four cases (eight eyes) out of the nine retinoschisis cases were tested with Ganzfeld ERG at the same day. The results showed statistically significant difference of average response densities and latencies in six ring retinal regions between the normal control and retinoschisis. The trace array and 3-D topography of multifocal ERG showed multi-area amplitude decrease with absence or reduction of central peak amplitude in patients with retinoschisis. The P1/N1 ratio of multifocal ERG average response densities in six ring retinal regions was different from the b/a ratio of Ganzfeld ERG. The multifocal ERG and Ganzfeld ERG each had its advantage in the diagnosis of retinoschisis.

  10. Rod-driven OFF pathway responses in the distal retina: dark-adapted flicker electroretinogram in mouse.

    PubMed

    Lei, Bo

    2012-01-01

    The rodent retina does not exhibit a positive OFF-response in the electroretinogram (ERG), which makes it difficult to evaluate its OFF-pathway functions in vivo. We studied the rod-driven OFF pathway responses by using a dark-adapted 10-Hz flicker ERG procedure in mouse. Conventional ERGs and 10-Hz dark-adapted flicker ERGs were obtained in wild-type mice (C57BL/6), in mice with pure rod (cpfl1) or pure cone (rho(-/-)) function, and in nob1 mice which have a selective ON-pathway defect. To isolate the response from ON or OFF pathway, glutamate analogs 2-amino-4-phosphobutyric acid (APB, an ON pathway blocker) and cis-2, 3-piperidine-dicarboxylic acid (PDA, an OFF pathway blocker), were injected intravitreally. The amplitude-intensity profile of the dark-adapted 10-Hz flicker ERG in the wild-type mice exhibits two peaks at middle and high light intensities. The two peaks represent rod- and cone-driven responses respectively. In APB-treated C57BL/6 mice and in nob1 mice, the dark-adapted ERG b-waves were absent. However, both rod- and cone-driven OFF pathway responses were evident with flicker ERG recording. At middle light intensities that activate only rod system, the flicker ERG responses in saline-injected nob1 mice were similar to those in APB-injected cpfl1 mice and wild-type mice. These responses are sensitive to PDA. The amplitudes of these rod-driven OFF pathway responses were approximately 20% of the total rod-driven flicker ERG responses. We demonstrate that the rod-OFF bipolar cell pathway is functional in the outer retina. The dark-adapted flicker ERG is practical for the evaluation of rod- and cone-driven responses, and the residual OFF pathway signals in subjects with ON pathway defects.

  11. Down-regulation of ether-a-go-go-related gene potassium channel protein through sustained stimulation of AT1 receptor by angiotensin II.

    PubMed

    Cai, Yue; Wang, Yuhong; Xu, Jia; Zuo, Xu; Xu, Yanfang

    2014-09-26

    We investigated the effects of AT1 receptor stimulation by angiotensin II (Ang II) on human ether-a-go-go-related gene (hERG) potassium channel protein in a heterogeneous expression system with the human embryonic kidney (HEK) 293 cells which stably expressed hERG channel protein and were transiently transfected with the human AT1 receptors (HEK293/hERG). Western-blot analysis showed that Ang II significantly decreased the expression of mature hERG channel protein (155-kDa band) in a time- and dose-dependent manner without affecting the level of immature hERG channel protein (135-kDa band). The relative intensity of 155-kDa band was 64.7±6.8% of control (P<0.01) after treatment of Ang II at 100nM for 24h. To investigate the effect of Ang II on the degradation of mature hERG channel protein, we blocked forward trafficking from ER to Golgi with a Golgi transit inhibitor brefeldin A (10μM). Ang II significantly enhanced the time-dependent reduction of mature hERG channel protein. In addition, the proteasomal inhibitor lactacystin (5μM) inhibited Ang II-mediated the reduction of mature hERG channel protein, but the lysosomal inhibitor bafilomycin A1 (1μM) had no effect on the protein. The protein kinase C (PKC) inhibitor bisindolylmaleimide 1 (1μM) antagonized the reduction of mature hERG channel protein induced by Ang II. The results indicate that sustained stimulation of AT1 receptors by Ang II reduces the mature hERG channel protein via accelerating channel proteasomal degradation involving the PKC pathway. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Altered sterol metabolism in budding yeast affects mitochondrial iron-sulfur (Fe-S) cluster synthesis.

    PubMed

    Ward, Diane M; Chen, Opal S; Li, Liangtao; Kaplan, Jerry; Bhuiyan, Shah Alam; Natarajan, Selvamuthu K; Bard, Martin; Cox, James E

    2018-05-17

    Ergosterol synthesis is essential for cellular growth and viability of the budding yeast Saccharomyces cerevisiae, and intracellular sterol distribution and homeostasis are therefore highly regulated in this species. Erg25 is an iron-containing C4-methyl sterol oxidase that contributes to the conversion of 4,4-dimethylzymosterol to zymosterol, a precursor of ergosterol. The ERG29 gene encodes an endoplasmic reticulum (ER)-associated protein, and here we identified a role for Erg29 in the methyl sterol oxidase step of ergosterol synthesis. ERG29 deletion resulted in lethality in respiring cells, but respiration-incompetent (Rho- or Rho0) cells survived, suggesting that Erg29 loss leads to accumulation of oxidized sterol metabolites that affect cell viability. Down-regulation of ERG29 expression in Δerg29 cells indeed led to accumulation of methyl sterol metabolites, resulting in increased mitochondrial oxidants and a decreased ability of mitochondria to synthesize iron-sulfur (Fe-S) clusters due to reduced levels of Yfh1, the mammalian frataxin homolog, which is involved in mitochondrial Fe metabolism. Using a high-copy genomic library, we identified suppressor genes that permitted growth of Δerg29 cells on respiratory substrates, and these included genes encoding the mitochondrial proteins Yfh1, Mmt1, Mmt2, and Pet20, which reversed all phenotypes associated with loss of ERG29. Of note, loss of Erg25 also resulted in accumulation of methyl sterol metabolites and also increased mitochondrial oxidants and degradation of Yfh1. We propose that accumulation of toxic intermediates of the methyl sterol oxidase reaction increase mitochondrial oxidants, which affect Yfh1 protein stability. These results indicate an interaction between sterols generated by ER proteins and mitochondrial iron metabolism. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Genetic transformation of Neurospora tetrasperma, demonstration of repeat-induced point mutation (RIP) in self-crosses and a screen for recessive RIP-defective mutants.

    PubMed Central

    Bhat, Ashwin; Tamuli, Ranjan; Kasbekar, Durgadas P

    2004-01-01

    The pseudohomothallic fungus Neurospora tetrasperma is naturally resistant to the antibiotic hygromycin. We discovered that mutation of its erg-3 (sterol C-14 reductase) gene confers a hygromycin-sensitive phenotype that can be used to select transformants on hygromycin medium by complementation with the N. crassa erg-3+ and bacterial hph genes. Cotransformation of hph with PCR-amplified DNA of other genes enabled us to construct strains duplicated for the amplified DNA. Using transformation we constructed self-fertile strains that were homoallelic for an ectopic erg-3+ transgene and a mutant erg-3 allele at the endogenous locus. Self-crosses of these strains yielded erg-3 mutant ascospores that produced colonies with the characteristic morphology on Vogel's sorbose agar described previously for erg-3 mutants of N. crassa. The mutants were generated by repeat-induced point mutation (RIP), a genome defense process that causes numerous G:C to A:T mutations in duplicated DNA sequences. Homozygosity for novel recessive RIP-deficient mutations was signaled by self-crosses of erg-3-duplication strains that fail to produce erg-3 mutant progeny. Using this assay we isolated a UV-induced mutant with a putative partial RIP defect. RIP-induced mutants were isolated in rid-1 and sad-1, which are essential genes, respectively, for RIP and another genome defense mechanism called meiotic silencing by unpaired DNA. PMID:15280231

  14. Color vision abnormality as an initial presentation of the complete type of congenital stationary night blindness.

    PubMed

    Tan, Xue; Aoki, Aya; Yanagi, Yasuo

    2013-01-01

    Patients with the complete form of congenital stationary night blindness (CSNB) often have reduced visual acuity, myopia, impaired night vision, and sometimes nystagmus and strabismus, however, they seldom complain of color vision abnormality. A 17-year-old male who was at technical school showed abnormalities in the color perception test for employment, and was referred to our hospital for a detailed examination. He had no family history of color vision deficiency and no other symptoms. During the initial examination, his best-corrected visual acuity was 1.2 in both eyes. His fundus showed no abnormalities except for somewhat yellowish reflex in the fovea of both eyes. Electroretinogram (ERG) showed a good response in cone ERG and 30 Hz flicker ERG, however, the bright flash, mixed rod and cone ERG showed a negative type with a reduced b-wave (positive deflection). There was no response in the rod ERG, either. From the findings of the typical ERG, the patient was diagnosed with complete congenital stationary night blindness. This case underscores the importance of ERG in order to diagnose the cause of a color vision anomaly.

  15. Case of adult-onset neuronal intranuclear hyaline inclusion disease with negative electroretinogram.

    PubMed

    Yamada, Wataru; Takekoshi, Akira; Ishida, Kyoko; Mochizuki, Kiyofumi; Sone, Jun; Sobue, Gen; Hayashi, Yuichi; Inuzuka, Takashi; Miyake, Yozo

    2017-06-01

    To report the findings in a 72-year-old man with neuronal intranuclear hyaline inclusion disease (NIHID) with the negative-type electroretinogram (ERG) and without night blindness. Standard ophthalmological examinations including the medical history, measurements of the best-corrected visual acuity and intraocular pressures, slit-lamp biomicroscopy, ophthalmoscopy, spectral-domain optical coherence tomography, fundus autofluorescence, and perimetry were performed. In addition, neurological and electrophysiological examinations were performed. NIHID was confirmed by skin biopsy. The ophthalmologic examinations revealed sluggish pupillary reflexes without visual disturbances and retinal abnormalities. The amplitudes of the dark-adapted 0.01 ERG was absent, and light-adapted 3 ERG and light-adapted 30 Hz flicker ERG were reduced in amplitude and delayed in implicit time. The rod system was more severely affected than the cone system, indicating that NIHID is classified as one of rod-cone dysfunction syndrome. The dark-adapted 3 ERG consisted of a markedly reduced b-wave with larger a-wave (negative ERG), but the amplitude of a-wave was smaller than normal. Since the ophthalmoscopical findings and the subjective visual functions may be essentially normal, the characteristic ERG abnormalities can be an important findings in adult-onset NIHID without night blindness.

  16. Electroretinography: A biopotential to assess the function/dysfunction of the retina

    NASA Astrophysics Data System (ADS)

    Quintana, Quinteros; Benedetto, M. L.; Maldonado, M. M.; de Payer E., A. C. Vera; Contin, M. A.

    2016-04-01

    The Electroretinography (ERG) is a noninvasive technique that allows the assessment of functional integrity of the retina. The ERG recordings are biopotencials acquired in the corneal surface as a response of retinal tissue against controlled light stimuli. In clinical ophthalmology ERG is not commonly used but nowadays, because of the high incidence of degenerative diseases of the retina (RD), its use should be increased. Like other biopotentials as electrocardiography (ECG), electroencephalogram (EEG) and electromyography (EMG), ERG is a low amplitude signal, in this case a few hundred of microvolts (µV), which must be fitted and processed. The ERG signals are affected in morphology in the presence of pathologies that affects the integrity of the different retinal cell groups, for example due to some RD. In advanced cases of RD recordings can be abolished in the time domain; and yet in them it is believed that there is relevant clinical information making the ERG a great potential diagnostic tool.

  17. Comparing three different modes of electroretinography in experimental glaucoma: diagnostic performance and correlation to structure.

    PubMed

    Wilsey, Laura; Gowrisankaran, Sowjanya; Cull, Grant; Hardin, Christy; Burgoyne, Claude F; Fortune, Brad

    2017-04-01

    To compare diagnostic performance and structure-function correlations of multifocal electroretinogram (mfERG), full-field flash ERG (ff-ERG) photopic negative response (PhNR) and transient pattern-reversal ERG (PERG) in a non-human primate (NHP) model of experimental glaucoma (EG). At baseline and after induction of chronic unilateral IOP elevation, 43 NHP had alternating weekly recordings of retinal nerve fiber layer thickness (RNFLT) by spectral domain OCT (Spectralis) and retinal function by mfERG (7F slow-sequence stimulus, VERIS), ff-ERG (red 0.42 log cd-s/m 2 flashes on blue 30 scotopic cd/m 2 background, LKC UTAS-E3000), and PERG (0.8° checks, 99% contrast, 100 cd/m 2 mean, 5 reversals/s, VERIS). All NHP were followed at least until HRT-confirmed optic nerve head posterior deformation, most to later stages. mfERG responses were filtered into low- and high-frequency components (LFC, HFC, >75 Hz). Peak-to-trough amplitudes of LFC features (N1, P1, N2) and HFC RMS amplitudes were measured and ratios calculated for HFC:P1 and N2:P1. ff-ERG parameters included A-wave (at 10 ms), B-wave (trough-to-peak) and PhNR (baseline-to-trough) amplitudes as well as PhNR:B-wave ratio. PERG parameters included P50 and N95 amplitudes as well as N95:P50 ratio and N95 slope. Diagnostic performance of retinal function parameters was compared using the area under the receiver operating characteristic curve (A-ROC) to discriminate between EG and control eyes. Correlations to RNFLT were compared using Steiger's test. Study duration was 15 ± 8 months. At final follow-up, structural damage in EG eyes measured by RNFLT ranged from 9% above baseline (BL) to 58% below BL; 29/43 EG eyes (67%) and 0/43 of the fellow control eyes exhibited significant (>7%) loss of RNFLT from BL. Using raw parameter values, the largest A-ROC findings for mfERG were: HFC (0.82) and HFC:P1 (0.90); for ff-ERG: PhNR (0.90) and PhNR:B-wave (0.88) and for PERG: P50 (0.64) and N95 (0.61). A-ROC increased

  18. The use of exploratory analyses within the National Institute for Health and Care Excellence single technology appraisal process: an evaluation and qualitative analysis.

    PubMed

    Kaltenthaler, Eva; Carroll, Christopher; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2016-04-01

    As part of the National Institute for Health and Care Excellence (NICE) single technology appraisal (STA) process, independent Evidence Review Groups (ERGs) critically appraise the company submission. During the critical appraisal process the ERG may undertake analyses to explore uncertainties around the company's model and their implications for decision-making. The ERG reports are a central component of the evidence considered by the NICE Technology Appraisal Committees (ACs) in their deliberations. The aim of this research was to develop an understanding of the number and type of exploratory analyses undertaken by the ERGs within the STA process and to understand how these analyses are used by the NICE ACs in their decision-making. The 100 most recently completed STAs with published guidance were selected for inclusion in the analysis. The documents considered were ERG reports, clarification letters, the first appraisal consultation document and the final appraisal determination. Over 400 documents were assessed in this study. The categories of types of exploratory analyses included fixing errors, fixing violations, addressing matters of judgement and the ERG-preferred base case. A content analysis of documents (documentary analysis) was undertaken to identify and extract relevant data, and narrative synthesis was then used to rationalise and present these data. The level and type of detail in ERG reports and clarification letters varied considerably. The vast majority (93%) of ERG reports reported one or more exploratory analyses. The most frequently reported type of analysis in these 93 ERG reports related to the category 'matters of judgement', which was reported in 83 (89%) reports. The category 'ERG base-case/preferred analysis' was reported in 45 (48%) reports, the category 'fixing errors' was reported in 33 (35%) reports and the category 'fixing violations' was reported in 17 (18%) reports. The exploratory analyses performed were the result of issues

  19. Issues Related to the Frequency of Exploratory Analyses by Evidence Review Groups in the NICE Single Technology Appraisal Process.

    PubMed

    Kaltenthaler, Eva; Carroll, Christopher; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2017-06-01

    Evidence Review Groups (ERGs) critically appraise company submissions as part of the National Institute for Health and Care Excellence (NICE) Single Technology Appraisal (STA) process. As part of their critique of the evidence submitted by companies, the ERGs undertake exploratory analyses to explore uncertainties in the company's model. The aim of this study was to explore pre-defined factors that might influence or predict the extent of ERG exploratory analyses. The aim of this study was to explore predefined factors that might influence or predict the extent of ERG exploratory analyses. We undertook content analysis of over 400 documents, including ERG reports and related documentation for the 100 most recent STAs (2009-2014) for which guidance has been published. Relevant data were extracted from the documents and narrative synthesis was used to summarise the extracted data. All data were extracted and checked by two researchers. Forty different companies submitted documents as part of the NICE STA process. The most common disease area covered by the STAs was cancer (44%), and most ERG reports (n = 93) contained at least one exploratory analysis. The incidence and frequency of ERG exploratory analyses does not appear to be related to any developments in the appraisal process, the disease area covered by the STA, or the company's base-case incremental cost-effectiveness ratio (ICER). However, there does appear to be a pattern in the mean number of analyses conducted by particular ERGs, but the reasons for this are unclear and potentially complex. No clear patterns were identified regarding the presence or frequency of exploratory analyses, apart from the mean number conducted by individual ERGs. More research is needed to understand this relationship.

  20. A CTG Clade Candida Yeast Genetically Engineered for the Genotype-Phenotype Characterization of Azole Antifungal Resistance in Human-Pathogenic Yeasts.

    PubMed

    Accoceberry, Isabelle; Rougeron, Amandine; Biteau, Nicolas; Chevrel, Pauline; Fitton-Ouhabi, Valérie; Noël, Thierry

    2018-01-01

    A strain of the opportunistic pathogenic yeast Candida lusitaniae was genetically modified for use as a cellular model for assessing by allele replacement the impact of lanosterol C14α-demethylase ERG11 mutations on azole resistance. Candida lusitaniae was chosen because it is susceptible to azole antifungals, it belongs to the CTG clade of yeast, which includes most of the Candida species pathogenic for humans, and it is haploid and easily amenable to genetic transformation and molecular modeling. In this work, allelic replacement is targeted at the ERG11 locus by the reconstitution of a functional auxotrophic marker in the 3' intergenic region of ERG11 Homologous and heterologous ERG11 alleles are expressed from the resident ERG11 promoter of C. lusitaniae , allowing accurate comparison of the phenotypic change in azole susceptibility. As a proof of concept, we successfully expressed in C. lusitaniae different ERG11 alleles, either bearing or not bearing mutations retrieved from a clinical context, from two phylogenetically distant yeasts, C. albicans and Kluyveromyces marxianus Candida lusitaniae constitutes a high-fidelity expression system, giving specific Erg11p-dependent fluconazole MICs very close to those observed with the ERG11 donor strain. This work led us to characterize the phenotypic effect of two kinds of mutation: mutation conferring decreased fluconazole susceptibility in a species-specific manner and mutation conferring fluconazole resistance in several yeast species. In particular, a missense mutation affecting amino acid K143 of Erg11p in Candida species, and the equivalent position K151 in K. marxianus , plays a critical role in fluconazole resistance. Copyright © 2017 American Society for Microbiology.

  1. Structure-activity relationships of pentamidine-affected ion channel trafficking and dofetilide mediated rescue.

    PubMed

    Varkevisser, R; Houtman, M J C; Linder, T; de Git, K C G; Beekman, H D M; Tidwell, R R; Ijzerman, A P; Stary-Weinzinger, A; Vos, M A; van der Heyden, M A G

    2013-07-01

    Drug interference with normal hERG protein trafficking substantially reduces the channel density in the plasma membrane and thereby poses an arrhythmic threat. The chemical substructures important for hERG trafficking inhibition were investigated using pentamidine as a model drug. Furthermore, the relationship between acute ion channel block and correction of trafficking by dofetilide was studied. hERG and K(IR)2.1 trafficking in HEK293 cells was evaluated by Western blot and immunofluorescence microscopy after treatment with pentamidine and six pentamidine analogues, and correction with dofetilide and four dofetilide analogues that displayed different abilities to inhibit IKr . Molecular dynamics simulations were used to address mode, number and type of interactions between hERG and dofetilide analogues. Structural modifications of pentamidine differentially affected plasma membrane levels of hERG and K(IR)2.1. Modification of the phenyl ring or substituents directly attached to it had the largest effect, affirming the importance of these chemical residues in ion channel binding. PA-4 had the mildest effects on both ion channels. Dofetilide corrected pentamidine-induced hERG, but not K(IR)2.1 trafficking defects. Dofetilide analogues that displayed high channel affinity, mediated by pi-pi stacks and hydrophobic interactions, also restored hERG protein levels, whereas analogues with low affinity were ineffective. Drug-induced trafficking defects can be minimized if certain chemical features are avoided or 'synthesized out'; this could influence the design and development of future drugs. Further analysis of such features in hERG trafficking correctors may facilitate the design of a non-blocking corrector for trafficking defective hERG proteins in both congenital and acquired LQTS. © 2013 The British Pharmacological Society.

  2. Edge-Region Grouping in Figure-Ground Organization and Depth Perception

    ERIC Educational Resources Information Center

    Palmer, Stephen E.; Brooks, Joseph L.

    2008-01-01

    Edge-region grouping (ERG) is proposed as a unifying and previously unrecognized class of relational information that influences figure-ground organization and perceived depth across an edge. ERG occurs when the edge between two regions is differentially grouped with one region based on classic principles of similarity grouping. The ERG hypothesis…

  3. Alteration of rod and cone function in children with Usher syndrome.

    PubMed

    Malm, Eva; Ponjavic, Vesna; Möller, Claes; Kimberling, William J; Stone, Edwin S; Andréasson, Sten

    2011-01-01

    To evaluate the retinal function, with emphasis on phenotype and rate of progression, in infants and children with different genotypes of Usher syndrome. Fourteen children (2-10 years of age) with retinitis pigmentosa and hearing impairment were examined with full-field electroretinography (ERG) during general anesthesia, ophthalmologic examination, and genetic analysis. Five children were repeatedly examined (follow-up 5-10 years) with full-field ERG under local anesthesia and in 2 children multifocal ERG and optical coherence tomography (OCT) were performed. These results were compared to full-field ERG data from 58 children without retinal eye disorder. Six children were genotyped as Usher 1B, 2A, and 3A. Full-field ERG demonstrated early alterations corresponding to a rod-cone dystrophy in all children. A remaining rod function could be verified in the majority of the children up to 4 years of age. After 4 years of age, there was a further deterioration of the rod function; the progress was severe in Usher types 1 and 2 and moderate in Usher type 3. In all children, the cone function was moderately reduced, in a few cases almost normal. The results from the 58 children without retinal disorder confirm that full-field ERG during general anesthesia is reliable. Multifocal ERG confirmed a preserved central cone function and in OCT there were discrete structural alterations. Full-field ERG during general anesthesia in children with Usher syndrome demonstrates variable phenotypes and different degrees in rate of progression during childhood.

  4. Juvenile X-linked retinoschisis with normal scotopic b-wave in the electroretinogram at an early stage of the disease.

    PubMed

    Eksandh, Louise; Andréasson, Sten; Abrahamson, Magnus

    2005-09-01

    To report four cases of genetically verified juvenile X-linked retinoschisis (XLRS) with normal scotopic b-waves in full-field ERG, including one patient with a novel mutation (W50X) in the RS1 gene. Four XLRS patients from different families were examined with regard to visual acuity, kinetic perimetry, fundus photography, full-field ERG, and OCT. Two of these patients were also examined with multifocal-ERG (mfERG). Mutations in the RS1 gene were identified by sequence analysis. The full-field ERG presented normal b-wave amplitudes on scotopic white-light stimulation. OCT and mfERG presented macular schisis and macular dysfunction. Genetic analysis revealed a deletion of exon 1 and the promotor region in one patient and mutations giving rise to the amino acid substitutions R209C and W96R in two others. The fourth patient carried a novel mutation in exon 3 of the RS1 gene (nt 149 G-->A), causing the introduction of a stop codon after amino acid 49 in the RS protein. Four young males with XLRS did not present with reduction in the scotopic b-wave amplitude on full-field ERG, which is otherwise often considered to be characteristic of the disease. Full-field ERG and molecular genetic analysis of the RS1 gene still remain the most important diagnostic tools for this retinal disorder, although the OCT can be a valuable complement in order to make the diagnosis at an early stage.

  5. Development of extended-release solid dispersion granules of tacrolimus: evaluation of release mechanism and human oral bioavailability.

    PubMed

    Tsunashima, Daisuke; Yamashita, Kazunari; Ogawara, Ken-Ichi; Sako, Kazuhiro; Hakomori, Tadashi; Higaki, Kazutaka

    2017-12-01

    We aimed to prepare a once-daily modified-release oral formulation of tacrolimus by utilizing an extended-release granules (ERG). Extended-release granules were prepared using ethylcellulose (EC), hydroxypropylmethylcellulose (HPMC) and lactose via a solvent evaporation method with ethanol. Physicochemical and biopharmaceutical studies were performed to determine the formulation with optimum release profile of tacrolimus from ERG. Tacrolimus existed in an amorphous state in ERG. Tacrolimus release from ERG was attenuated by EC and facilitated by lactose, suggesting that drug release kinetics could adequately be regulated by these components. Those release profiles were consistent with Higuchi's equation, suggesting a diffusion-type release mechanism. Smooth surface of ERG changed to the structure with pores after the release test, likely derived from the dissolution of HPMC and lactose. But ERG structure formed by EC was still maintained after the release test, leading to the longer maintenance of diffusion-type release. Two ERG formulations selected by blood concentration simulation successfully provided long-term retention of tacrolimus in blood in a human absorption study. We successfully developed the formulation exhibiting a significant reduction in C max , the longer mean residence time and AUC close to that of an immediate-release tacrolimus formulation, being preferred from the viewpoint of safe and effective immunosuppressant pharmacotherapy. © 2017 Royal Pharmaceutical Society.

  6. Immunohistochemical expression of Ets-related gene-transcriptional factor in adenocarcinoma prostate and its correlation with Gleason score.

    PubMed

    Mannan, Rahul; Bhasin, Tejinder Singh; Manjari, Mridu; Singh, Gagandeep; Bhatia, Puneet Kaur; Sharma, Sonam

    2016-01-01

    Prostate carcinoma is the second leading cause of cancer-related deaths in males worldwide. The burden is expected to grow 1.7 million new cases and 499,000 new deaths by 2030. In developing countries such as India, prostate carcinoma will show an increase by 140% in the next few years. Although the diagnosis of prostate carcinoma can usually be made on histological features, now a days many immunohistochemical (IHC) markers are used to distinguish it from benign mimickers as well as in predicting prognosis and treatment. Out of these markers, Ets-related gene (ERG product) is a proto-oncogene which participates in chromosomal translocations and is frequently over expressed in prostate carcinoma which harbors ERG-transmembrane protease, serine 2 fusion. Fifty cases of carcinoma prostate diagnosed in needle biopsies and prostatic chips, in the Department of Pathology of a tertiary care teaching hospital in Punjab, India, were included in the present study. The slides were observed under the light microscope, and Gleason scoring was done using the 2005 International Society of Urological Pathology modified Gleason system. IHC study for ERG expression was done on all the cases, for which anti-ERG monoclonal rabbit clone antibody EP111 (Dako, Denmark) was used. Lymphocytes and endothelial cells were taken as in built positive controls for staining. The intensity of ERG positivity was scored as no staining (0), weak staining (+1), moderate staining (+2) and intense staining (+3). The H score was then calculated by multiplying the intensity of the stain with the percentage (0-100) of the cells showing that staining intensity. The H-score has a range of 0-300. The relationship between IHC expression and clinico-pathological parameters was compared and analyzed using Chi-square test. P < 0.05 was considered statistically significant. Majority of patients included in the study were in the age group of 61-80 (84% of the total). When ERG expression was studied with age

  7. TRIMS: Validating T2 Molecular Effects for Neutrino Mass Experiments

    NASA Astrophysics Data System (ADS)

    Lin, Ying-Ting; Bodine, Laura; Enomoto, Sanshiro; Kallander, Matthew; Machado, Eric; Parno, Diana; Robertson, Hamish; Trims Collaboration

    2017-01-01

    The upcoming KATRIN and Project 8 experiments will measure the model-independent effective neutrino mass through the kinematics near the endpoint of tritium beta-decay. A critical systematic, however, is the understanding of the molecular final-state distribution populated by tritium decay. In fact, the current theory incorporated in the KATRIN analysis framework predicts an observable that disagrees with an experimental result from the 1950s. The Tritium Recoil-Ion Mass Spectrometer (TRIMS) experiment will reexamine branching ratio of the molecular tritium (T2) beta decay to the bound state (3HeT+). TRIMS consists of a magnet-guided time-of-flight mass spectrometer with a detector located on each end. By measuring the kinetic energy and time-of-flight difference of the ions and beta particles reaching the detectors, we will be able to distinguish molecular ions from atomic ones and hence derive the ratio in question.We will give an update on simulation software, analysis tools, and the apparatus, including early commissioning results. U.S. Department of Energy Office of Science, Office of Nuclear Physics, Award Number DE-FG02-97ER41020.

  8. Nuclear C-MYC expression level is associated with disease progression and potentially predictive of two year overall survival in prostate cancer.

    PubMed

    Zeng, Wen; Sun, Hanying; Meng, Fankai; Liu, Zeming; Xiong, Jing; Zhou, Sheng; Li, Fan; Hu, Jia; Hu, Zhiquan; Liu, Zheng

    2015-01-01

    Upregulation of nuclear C-MYC protein has been reported to be an early event in prostate cancer (PCa); however, its clinicopathological and prognostic significance remain controversial. We determined the association of nuclear C-MYC protein expression with clinicopathological parameters, prognosis, ETS-related gene (ERG) expression, and TMPRSS2-ERG status in PCa. Nuclear C-MYC and ERG expression by immunohistochemistry and TMPRSS2-ERG status by triple-color probe fluorescence in situ hybridization assay were determined in 50 hormone-naïve PCa patients and 31 radical prostatectomy specimens. Nuclear C-MYC immunostaining was negative, positive, and strong positive in 27.5%, 32.5%, and 40.0% of cases, respectively. C-MYC immunostaining was significantly associated with clinical T stage (P < 0.001), distant metastasis at the time of diagnosis (P < 0.001) and TMPRSS2-ERG status (P = 0.001) but not with ERG immunostaining (P = 0.818). In the Kaplan-Meier analysis, C-MYC positive cases were found to have worse 2-year OS compared with C-MYC negative cases (P = 0.027). However, in the univariate Cox analysis, only TMPRSS2-ERG status (hazard ratio [HR] 0.189, 95% CI 0.057-0.629; P = 0.007) and distant metastasis (HR 3.545, 95% CI 1.056-11.894; P = 0.040) were significantly associated with 2-year OS. After adjusting for these two factors, TMPRSS2-ERG status still impacted 2-year OS (HR 0.196, 95% CI 0.049-0.778; P = 0.020). Nuclear C-MYC overexpression may be associated with disease progression and potentially predictive of 2-year OS in PCa. This is the first study to demonstrate an association between nuclear C-MYC immunostaining and TMPRSS2-ERG status in PCa.

  9. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Wenhu, E-mail: wenhu.huang@pfizer.com; Collette, Walter; Twamley, Michelle

    Retinal ocular toxicity is among the leading causes of drug development attrition in the pharmaceutical industry. Electroretinography (ERG) is a non-invasive functional assay used to assess neuro-retinal physiological integrity by measuring the electrical responses. To directly assess the utility of ERG, a series of studies was conducted following intravitreal and/or iv administration of pan-cyclin-dependent kinase inhibitors: AG-012,986 and AG-024,322 in rats. Both compounds have previously shown to induce retinal toxicity. Retinal injury was evaluated by ERG, histopathology and TUNEL staining. Intravitreal injection of AG-012,986 at ≥ 10 μg/eye resulted in decreases (60%) in ERG b-wave and microscopic changes of mildmore » to moderate retinal degeneration, and at 30 μg/eye led to additional ophthalmic findings. Intravenous administration of AG-012,986 daily at ≥ 5 mg/kg resulted in dose-related decreases (25 to 40%) in b-wave and sporadic to intense positive TUNEL staining. Intravitreal injection of AG-024,322 at 30 μg/eye also resulted in decreases (50 to 60%) in b-wave, mild to marked retinal degeneration and mild vitreous debris. These experiments demonstrate that ERG can be used as a sensitive and reliable functional tool to evaluate retinal toxicity induced by test compounds in rats complementing other classical ocular safety measurements. - Highlights: • There were strong correlations of ERG readouts to in vivo ophthalmic exams, TUNEL assay, and histopathology. • ERG appears to be more sensitive and can detect retinal functional changes at a very early stage of pathogenesis. • ERG can be incorporated into routine exploratory toxicity study to identify compound ocular safety issues. • In drug discovery, ERG is a quick, non-invasive, sensitive and reliable tool in retinal toxicity de-risking.« less

  10. Relation Between Macular Retinal Ganglion Cell/Inner Plexiform Layer Thickness and Multifocal Electroretinogram Measures in Experimental Glaucoma

    PubMed Central

    Luo, Xunda; Patel, Nimesh B.; Rajagopalan, Lakshmi P.; Harwerth, Ronald S.; Frishman, Laura J.

    2014-01-01

    Purpose. We investigated relations between macular retinal ganglion cell plus inner plexiform layer (RGC+IPL) thickness and macular retinal function revealed by multifocal electroretinonography (mfERG) in a nonhuman primate model of experimental glaucoma. Methods. Retinal ganglion cell (RGC) structure and function were followed with spectral-domain optical coherence tomography (SD-OCT) and ERGs in five macaques with unilateral experimental glaucoma. Linear regression was used to study correlations in control (Con) and experimental (Exp) eyes between peripapillary retinal nerve fiber layer (RNFL) thickness, macular RGC+IPL thickness, multifocal photopic negative response (mfPhNR) and high-frequency multifocal oscillatory potentials (mfOP) in slow-sequence mfERG, and low-frequency component (mfLFC) in global-flash mfERG. We used ANOVA and paired t-tests to compare glaucoma-related mfERG changes between superior and inferior hemifields, foveal hexagon, inner three rings, and four quadrants of macula. Results. Average macular RGC+IPL and temporal RNFL thickness were strongly correlated (r2 = 0.90, P < 0.001). In hexagon-by-hexagon analysis, all three mfERG measures were correlated (P < 0.001) with RGC+IPL thickness for Con (r2, 0.33–0.51) and Exp eyes (r2, 0.17–0.35). The RGC structural and functional metrics decreased as eccentricity increased. The reduction in amplitude of mfERG measures in Exp eyes relative to Con eyes was proportionally greater, in general, than the relative thinning of RGC+IPL at the same location for eyes in which structural loss was not evident, or mild to moderate. Although not statistically significant, percent amplitude reduction of mfERG measures was greatest in the inferior temporal quadrant. Conclusions. Macular RGC+IPL thickness and mfERG measures of RGC function can be complementary tools in assessing glaucomatous neuropathy. PMID:24970256

  11. Clinical Phenotypes and Prognostic Full-Field Electroretinographic Findings in Stargardt Disease

    PubMed Central

    ZAHID, SARWAR; JAYASUNDERA, THIRAN; RHOADES, WILLIAM; BRANHAM, KARI; KHAN, NAHEED; NIZIOL, LESLIE M.; MUSCH, DAVID C.; HECKENLIVELY, JOHN R.

    2013-01-01

    PURPOSE To investigate the relationships between clinical and full-field electroretinographic (ERG) findings and progressive loss of visual function in Stargardt disease. DESIGN Retrospective cohort study. METHODS We performed a retrospective review of data from 198 patients with Stargardt disease. Measures of visual function over time, including visual acuity, quantified Goldmann visual fields, and full-field ERG data were recorded. Data were analyzed using SAS statistical software. Subgroup analyses were performed on 148 patients with ERG phenotypic data, 46 patients with longitudinal visual field data, and 92 patients with identified ABCA4 mutations (46 with 1 mutation, and 47 with 2 or more mutations). RESULTS Of 46 patients with longitudinal visual field data, 8 patients with faster central scotoma progression rates had significantly worse scotopic B-wave amplitudes at their initial assessment than 20 patients with stable scotomata (P = .014) and were more likely to have atrophy beyond the arcades (P = .047). Overall, 47.3% of patients exhibited abnormal ERG results, with rod–cone dysfunction in 14.2% of patients, cone–rod dysfunction in 17.6% of patients, and isolated cone dysfunction in 15.5% of patients. Abnormal values in certain ERG parameters were associated significantly with (maximum-stimulation A- and B-wave amplitudes) or tended toward (photopic and scotopic B-wave amplitudes) a higher mean rate of central scotoma progression compared with those patients with normal ERG values. Scotoma size and ERG parameters differed significantly between those with a single mutation versus those with multiple mutations. CONCLUSIONS Full-field ERG examination provides clinically relevant information regarding the severity of Stargardt disease, likelihood of central scotoma expansion, and visual acuity deterioration. Patients also may exhibit an isolated cone dystrophy on ERG examination. PMID:23219216

  12. Characterization of Squalene Epoxidase of Saccharomyces cerevisiae by Applying Terbinafine-Sensitive Variants▿

    PubMed Central

    Ruckenstuhl, Christoph; Lang, Silvia; Poschenel, Andrea; Eidenberger, Armin; Baral, Pravas Kumar; Kohút, Peter; Hapala, Ivan; Gruber, Karl; Turnowsky, Friederike

    2007-01-01

    Squalene epoxidase (SE) is the target of terbinafine, which specifically inhibits the fungal enzyme in a noncompetitive manner. On the basis of functional homologies to p-hydroxybenzoate hydroxylase (PHBH) from Pseudomonas fluorescens, the Erg1 protein contains two flavin adenine dinucleotide (FAD) domains and one nucleotide binding (NB) site. By in vitro mutagenesis of the ERG1 gene, which codes for the Saccharomyces cerevisiae SE, we isolated erg1 alleles that conferred increased terbinafine sensitivity or that showed a lethal phenotype when they were expressed in erg1-knockout strain KLN1. All but one of the amino acid substitutions affected conserved FAD/nucleotide binding sites. The G25S, D335X (W, F, P), and G210A substitutions in the FADI, FADII, and NB sites, respectively, rendered the SE variants nonfunctional. The G30S and L37P variants exhibited decreased enzymatic activity, accompanied by a sevenfold increase in erg1 mRNA levels and an altered sterol composition, and rendered KLN1 more sensitive not only to allylamines (10 to 25 times) but also to other ergosterol biosynthesis inhibitors. The R269G variant exhibited moderately reduced SE activity and a 5- to 10-fold increase in allylamine sensitivity but no cross-sensitivity to the other ergosterol biosynthesis inhibitors. To further elucidate the roles of specific amino acids in SE function and inhibitor interaction, a homology model of Erg1p was built on the basis of the crystal structure of PHBH. All experimental data obtained with the sensitive Erg1 variants support this model. In addition, the amino acids responsible for terbinafine resistance, although they are distributed along the sequence of Erg1p, cluster on the surface of the Erg1p model, giving rise to a putative binding site for allylamines. PMID:17043127

  13. Structure-activity relationships of pentamidine-affected ion channel trafficking and dofetilide mediated rescue

    PubMed Central

    Varkevisser, R; Houtman, M J C; Linder, T; de Git, K C G; Beekman, H D M; Tidwell, R R; IJzerman, A P; Stary-Weinzinger, A; Vos, M A; van der Heyden, M A G

    2013-01-01

    Background and Purpose Drug interference with normal hERG protein trafficking substantially reduces the channel density in the plasma membrane and thereby poses an arrhythmic threat. The chemical substructures important for hERG trafficking inhibition were investigated using pentamidine as a model drug. Furthermore, the relationship between acute ion channel block and correction of trafficking by dofetilide was studied. Experimental Approach hERG and KIR2.1 trafficking in HEK293 cells was evaluated by Western blot and immunofluorescence microscopy after treatment with pentamidine and six pentamidine analogues, and correction with dofetilide and four dofetilide analogues that displayed different abilities to inhibit IKr. Molecular dynamics simulations were used to address mode, number and type of interactions between hERG and dofetilide analogues. Key Results Structural modifications of pentamidine differentially affected plasma membrane levels of hERG and KIR2.1. Modification of the phenyl ring or substituents directly attached to it had the largest effect, affirming the importance of these chemical residues in ion channel binding. PA-4 had the mildest effects on both ion channels. Dofetilide corrected pentamidine-induced hERG, but not KIR2.1 trafficking defects. Dofetilide analogues that displayed high channel affinity, mediated by pi-pi stacks and hydrophobic interactions, also restored hERG protein levels, whereas analogues with low affinity were ineffective. Conclusions and Implications Drug-induced trafficking defects can be minimized if certain chemical features are avoided or ‘synthesized out’; this could influence the design and development of future drugs. Further analysis of such features in hERG trafficking correctors may facilitate the design of a non-blocking corrector for trafficking defective hERG proteins in both congenital and acquired LQTS. PMID:23586323

  14. Natural sleep modifies the rat electroretinogram.

    PubMed Central

    Galambos, R; Juhász, G; Kékesi, A K; Nyitrai, G; Szilágyi, N

    1994-01-01

    We show here electroretinograms (ERGs) recorded from freely moving rats during sleep and wakefulness. Bilateral ERGs were evoked by flashes delivered through a light-emitting diode implanted under the skin above one eye and recorded through electrodes inside each orbit near the optic nerve. Additional electrodes over each visual cortex monitored the brain waves and collected flash-evoked cortical potentials to compare with the ERGs. Connections to the stimulating and recording instruments through a plug on the head made data collection possible at any time without physically disturbing the animal. The three major findings are (i) the ERG amplitude during slow-wave sleep can be 2 or more times that of the waking response; (ii) the ERG patterns in slow-wave and REM sleep are different; and (iii) the sleep-related ERG changes closely mimic those taking place at the same time in the responses evoked from the visual cortex. We conclude that the mechanisms that alter the visual cortical-evoked responses during sleep operate also and similarly at the retinal level. PMID:8197199

  15. The role of visual evoked potential and electroretinography in the preoperative assessment of osteo-keratoprosthesis or osteo-odonto-keratoprosthesis surgery.

    PubMed

    de Araujo, Aline L; Charoenrook, Victor; de la Paz, Maria F; Temprano, Jose; Barraquer, Rafael I; Michael, Ralph

    2012-09-01

    To determine the value of electroretinography (ERG) and visual evoked potential (VEP) in predicting visual outcome in patients undergoing osteo-keratoprosthesis (OKP) or osteo-odonto-keratoprosthesis (OOKP) surgery. We performed a retrospective cohort study of 143 eyes in 101 patients who underwent OKP or OOKP surgery. The subjects underwent ERG, VEP testing or both up to 6 months prior to surgery. The ERG and VEP results were classified into four categories based on wave amplitude, latency and configuration. The main outcome was the maximum best-corrected visual acuity (maxBCVA) reached at any time postoperatively. One hundred thirty-four cases had undergone preoperative ERG, 82 VEP and 73 both examinations. The sensitivities of ERG and VEP to detect maxBCVA≥0.05 were 68.5% and 87%, respectively, while the specificity was 63.2% for ERG and 47.4% for VEP. The maxBCVA was significantly better in patients with normal ERG (p=0.033) and those with normal VEP (p=0.048), once having defined appropriate normal and abnormal cut-off levels. When comparing fellow eyes in patients who underwent surgery in both eyes, maxBCVA was better in the eyes that had better VEP results (p=0.013). Eyes demonstrating normal ERG or VEP achieved better visual outcome than those with abnormal results. In addition, VEP proved instrumental in determining the eye with the best prognosis when comparing both eyes of a given patient. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

  16. Normal clinical electroretinography parameters for poodle, Labrador retriever, Thai ridgeback, and Thai Bangkaew

    PubMed Central

    Sussadee, Metita; Phavaphutanon, Janjira; Kornkaewrat, Kornchai

    2015-01-01

    The purpose of the present study was to establish normal electroretinogram (ERG) parameters using 56 normal eyes of four dog breeds common in Thailand: poodle, Labrador retriever, Thai ridgeback, and Thai Bangkaew. Standard ERG findings were bilaterally recorded using a handheld multi-species ERG unit with an ERG-jet lens electrode for 28 dogs under preanesthesia with diazepam, anesthesia with propofol, and anesthesia maintenance with isoflurane. There were significant differences in the mean values of ERG amplitudes and implicit times among the four dog breeds (p < 0.05) except for the b-wave implicit time of the photopic 30 Hz flicker response with 3 cd.s/m2 (p = 0.610). Out of the four breeds, Thai Bangkaew had the longest implicit time (p < 0.001) of scotopic low intensity responses, b-wave of scotopic standard intensity responses (3 cd.s/m2), a-wave of the higher intensity response (10 cd.s/m2), and a-wave of the photopic single flash response (3 cd.s/m2). For the b/a ratio, only the ratio of the Cone response was significantly different among the different breeds. In this summary, normal ERG parameters for four dog breeds were reported. Data from the investigation supported the hypothesis that determination of breed-specific limits of normality for ERG responses is necessary for individual clinics and laboratories. PMID:25269713

  17. Electroretinogram assessment of children with sensorineural hearing loss: implications for screening.

    PubMed

    West, Stephanie K; Hindocha, Maya; Hogg, Chris R; Holder, Graham E; Moore, Anthony T; Reddy, M Ashwin

    2015-10-01

    The guidelines of the National Deaf Children's Society recommend that children with sensorineural hearing loss (SNHL) be routinely screened for ophthalmological problems and suggest electroretinography (ERG) to exclude Usher syndrome. The present study reports the nature and prevalence of abnormal ERG findings in a cohort of children with SNHL undergoing ERG with the aim of identifying risk factors for the diagnosis of Usher syndrome. The medical records of children (<18 years of age) with SNHL referred for ERG at Moorfields Eye Hospital, London, between January 2009 and December 2011 were retrospectively reviewed. Patients were included if they had been referred with SNHL by an audiological medicine consultant and the primary indication for electrodiagnostic testing was possible Usher syndrome. A total of 84 cases met inclusion criteria of which 13 (15%) had ERG findings showing rod-cone dysfunction consistent with a diagnosis of Usher syndrome. Two patients with retinal pigmentary changes had normal ERGs and were diagnosed with rubella retinopathy based on the clinical findings. Risk factor analysis showed that age of ≥8 years at the time of ERG, sex, and bilateral hearing loss were not predictive of a diagnosis of Usher syndrome. However, the presence of or referral for cochlear implants, having relevant symptoms and/or clinical signs consistent with a retinal dystrophy, and profound hearing loss were all highly predictive. ERG is a useful diagnostic tool in children with SNHL and should be performed in children with SNHL who have cochlear implants and/or have signs or symptoms of retinal dystrophy. A focused approach could have potential cost-saving benefit. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  18. Edge-region grouping in figure-ground organization and depth perception.

    PubMed

    Palmer, Stephen E; Brooks, Joseph L

    2008-12-01

    Edge-region grouping (ERG) is proposed as a unifying and previously unrecognized class of relational information that influences figure-ground organization and perceived depth across an edge. ERG occurs when the edge between two regions is differentially grouped with one region based on classic principles of similarity grouping. The ERG hypothesis predicts that the grouped side will tend to be perceived as the closer, figural region. Six experiments are reported that test the predictions of the ERG hypothesis for 6 similarity-based factors: common fate, blur similarity, color similarity, orientation similarity, proximity, and flicker synchrony. All 6 factors produce the predicted effects, although to different degrees. In a 7th experiment, the strengths of these figural/depth effects were found to correlate highly with the strength of explicit grouping ratings of the same visual displays. The relations of ERG to prior results in the literature are discussed, and possible reasons for ERG-based figural/depth effects are considered. We argue that grouping processes mediate at least some of the effects we report here, although ecological explanations are also likely to be relevant in the majority of cases.

  19. Edge-Region Grouping in Figure-Ground Organization and Depth Perception

    PubMed Central

    Palmer, Stephen E.; Brooks, Joseph L.

    2008-01-01

    Edge-region grouping (ERG) is proposed as a unifying and previously unrecognized class of relational information that influences figure-ground organization and perceived depth across an edge. ERG occurs when the edge between two regions is differentially grouped with one region based on classic principles of similarity grouping. The ERG hypothesis predicts that the grouped side will tend to be perceived as the closer, figural region. Six experiments are reported that test the predictions of the ERG hypothesis for six similarity-based factors: common fate, blur similarity, color similarity, orientation similarity, proximity, and flicker synchrony. All six factors produce the predicted effects, although to different degrees. In the seventh experiment, the strengths of these figural/depth effects were found to correlate highly with the strength of explicit grouping ratings of the same visual displays. The relations of ERG to prior results in the literature are discussed, and possible reasons for ERG-based figural/depth effects are considered. We argue that grouping processes mediate at least some of the effects we report here, although ecological explanations are also likely to be relevant in the majority of cases. PMID:19045980

  20. Inhibition of Schistosoma mansoni ether-a-go-go related gene-encoded potassium channels leads to hypermotility and impaired egg production.

    PubMed

    Parker-Manuel, S J; Hahnel, S; Grevelding, C G

    2015-11-01

    The purpose of this work was to investigate the effect of ether-a-go-go related gene (ERG) potassium channel inhibition on Schistosoma mansoni. Use of dofetilide to block the schistosome ERGs resulted in a striking 'corkscrew' effect. The worms were unable to control their motility; they were hypermotile. The treated worms produced abnormal eggs, some of which consisted of little more than a spine. One of the S. mansoni ERGs (SmERGs), Smp_161140, was chosen for further study by RNAi. The transcript was knocked down to 50% compared to the controls. These RNAi-treated worms demonstrated seizure-like movements. In S. mansoni, as in other organisms, ERG channels seem to play a role in regulating muscle excitability. This work shows that egg production can be greatly reduced by effectively targeting muscle coordination in these important parasites. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Comparison of the human multifocal electroretinogram a-wave response and adaptive optics imaging of cone photoreceptor numbers

    NASA Astrophysics Data System (ADS)

    Klein, Michael W.

    Studies that have used pharmacological agents in non human primates (e.g., Hood et al., IOVS 2002) indicate that electrical activity of cone photoreceptors, depolarizing cone bipolar cells and horizontal cells are all likely to contribute to the multifocal electroretinogram (mfERG) a-wave. The purpose of this study was to examine the relationship between the mfERG a-wave and co-localized cone spatial density individually measured in young healthy human subjects. mfERGs (0.1-300Hz) were recorded from 4 subjects (20-29 years) with a system from Veris Science (EDI, Inc.) using 2.4 degree unstretched hexagons from 206 retinal locations presented at 30 frames per m-step on a 75Hz monitor with m-sequence exponent of 9 and flash strength 9.9 cd-s/m 2. mfERG a-wave amplitude was measured from baseline at 10 milliseconds on the leading edge of the a-wave. In vivo cone images were obtained at 24 retinal locations using a custom-built Adaptive Optics Confocal Scanning Laser Ophthalmoscope. Cone spatial density was measured from a 100x100mum centered on the mfERG hexagons at 24 retinal locations. mfERG a-wave amplitude as well as cone density reduced with increase in retinal eccentricity from the fovea and the a-wave amplitude and cone density were positively correlated for each subject (r2=0.35 to 0.49 and p = 0.0049 to 0.0002). The coefficient of variation (CV) of the mfERG a-wave amplitude across subjects at each retinal location (16-62%) was larger than the CV of the cone density (8-37%) at the same location. The results indicate that underlying cone density accounts for a significant portion (up to nearly 70%) of the variance in the mfERG a-wave amplitude across retinal eccentricity. Other factors likely contribute to the variance (approximately 30%) of the measured mfERG parameters.

  2. Effectiveness of Vascular Markers (Immunohistochemical Stains) in Soft Tissue Sarcomas.

    PubMed

    Naeem, Namra; Mushtaq, Sajid; Akhter, Noreen; Hussain, Mudassar; Hassan, Usman

    2018-05-01

    To ascertain the effectiveness of IHC markers of vascular origin like CD31, CD34, FLI1 and ERG in vascular soft tissue sarcomas including angiosarcomas, Kaposi sarcomas, epithelioid hemangioendothelioma and a non-vascular soft tissue sarcoma (Epithelioid sarcoma). Descriptive study. Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, from 2011 to 2017. Diagnosed cases of angiosarcomas (n=48), epithelioid hemangioendothelioma (n=9), Kaposi sarcoma (n=9) and epithelioid sarcoma (n=20) were selected. Immunohistochemical staining as performed on formalin fixed paraffin embedded sections. The sections were stained for the following markers: CD34 (VENTANA clone Q Bend 10), CD31 (Leica clone 1 A 10), FLI1 (CELL MARQUE clone MRQ-1) and ERG (CELL MARQUE clone EP111). A complete panel of CD34, CD31 and ERG was applied on 8/48 cases of angiosarcomas with triple positivity in 6 cases. Eight cases showed positivity for only CD31 and ERG and 2 cases showed positivity for only ERG. A complete panel of CD34, CD31 and ERG was applied on 3/9 cases of epithelioid hemangioendothelioma with positivity for all markers in 2 cases. Combined positivity for ERG and CD34 was seen in 2 cases and on 4 cases only CD31 immunohistochemical was solely applied with 100% positivity. FLI1 was not applied on any case. Among 9 cases of Kaposi sarcoma, ERG, CD34 and CD31 in combination were applied on only 1 case with triple positivity. Remaining cases show positivity for either CD34, CD31 or FLI1. Majority of cases of epithelioid sarcomas were diagnosed on the basis of cytokeratin and CD34 positivity with loss of INI1. The other vascular markers showed negativity in all cases. Among these four markers, ERG immunohistochemical stain is highly effective for endothelial differentiation due to its specific nuclear staining pattern in normal blood vessel endothelial cells (internal control) as well as neoplastic cells of vascular tumors and lack of background staining.

  3. Environmental Support to Amphibious Craft, Patrol Boats, and Coastal Ships: An Annotated Bibliography

    DTIC Science & Technology

    2008-03-05

    article describes the utility of the system to provide information on water level changes around Tampa Bay during Hurricane Andrew. Such a system could...sufficient observations. 85. Wyatt, Lucy R., Jim J. Green, Klaus-Werner Gurgel, Jose C. Nieto Borge, Konstanze Reichert, Katrin Hessner, Heinz Günther...through the ecosystems, and (5) patterns, frequencies and effects of disturbances such as hurricanes , landuse changes or forest harvesting. 99. Marine

  4. EVALUATION OF FULL-FIELD ELECTRORETINOGRAM REDUCTIONS AFTER OCRIPLASMIN TREATMENT

    PubMed Central

    Benz, Matthew S.; Miller, Daniel M.; Antoszyk, Andrew N.; Markoff, Joseph; Kozma, Petra; Meunier, Esmeralda; Sergott, Robert C.

    2018-01-01

    Purpose: To explore a possible association between full-field electroretinograms with vitreomacular adhesion resolution and best-corrected visual acuity as part of the prospective, randomized, double-masked, sham-controlled Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial studying ocriplasmin. Methods: The ERG substudy enrolled 62 of 220 OASIS subjects (randomized 2:1) and analyzed full-field electroretinograms and their association with both vitreomacular adhesion resolution and best-corrected visual acuity from baseline through Month 24. Electroretinogram reductions were defined as acute full-field electroretinogram reductions in amplitude of ≥40% from baseline occurring at postinjection Day 7 or Day 28. Results: In the ocriplasmin group, 16/40 (40%) subjects developed ERG reductions, compared to 1/21 (4.8%) in the sham group; 13/16 (81.3%) and 1/1 (100%) resolved by study end, respectively. A total of 11/16 (68.8%) ocriplasmin-treated subjects with ERG reductions achieved vitreomacular adhesion resolution, compared to those without (9/24, 37.5%). The ocriplasmin-treated subjects with ERG reductions also gained more letters on average (11.3 vs. 9.3 letters) from baseline and had a difference of 6.7 letters in mean best-corrected visual acuity by study end compared to those without ERG reductions. Conclusion: Ocriplasmin-treated subjects with ERG reductions had a higher rate of vitreomacular adhesion resolution and showed better visual improvement than their counterparts without ERG reductions or sham subjects by study end. PMID:28198785

  5. Multifocal electroretinographical changes in monkeys with experimental ocular hypertension: a longitudinal study.

    PubMed

    Kremers, Jan; Doelemeyer, Arno; Polska, Elzbieta A; Moret, Fabrice; Lambert, Christian; Lambrou, George N

    2008-07-01

    To study the time course of changes in the multifocal electroretinograms (mfERG) in monkeys with experimental ocular hypertension (OHT). The mfERGs were recorded in 12 eyes out of 6 monkeys. Two baseline measurements were used to quantify the reproducibility, the inter-ocular and the inter-individual variability of the ERG signals. Thereafter, the trabeculum of one eye of each animal was laser-coagulated in one to three sessions to induce OHT. ERG measurements were repeated regularly in a period of 18 months and the changes in ERG waveforms were quantified. All animals displayed OHT (between 20 and 50 mmHg) in the laser-coagulated eyes. An ERG change was defined as the sum of differences during the first 90 ms between the laser-coagulated eye and the same eye before laser coagulation and between the laser-coagulated eye and the non-treated fellow eye. Three animals displayed significant changes for nearly all retinal areas and all stimulus conditions. The three remaining animals displayed significant changes only in one comparison, indicating very mild changes. The data indicate that a high stimulus contrast is more sensitive to detect changes, probably because of a better signal-to-noise ratio. Moreover, the comparisons with the fellow eye are more sensitive to detect changes than comparisons with the measurements before laser-coagulation. OHT does not always lead to ERG changes. Comparisons with fellow eyes using high contrast stimuli are more sensitive to detect changes related to OHT.

  6. Ergothioneine Contents in Fruiting Bodies and Their Enhancement in Mycelial Cultures by the Addition of Methionine

    PubMed Central

    Lee, Wi Young; Ahn, Jin Kwon; Ka, Kang-Hyeon

    2009-01-01

    The levels of ergothioneine (ERG), which have been shown to act as an excellent antioxidant, were determined in both fruiting bodies and mycelia of various mushroom species. We found that ERG accumulated at different levels in fruiting bodies of mushrooms and showed up to a 92.3-fold difference between mushrooms. We also found that ERG accumulated at higher levels in mycelia than in fruiting bodies of economically important mushroom species such as Ganoderma neo-japonicum, G. applanatum and Paecilomyces tenuipes. The addition of 2 mM methionine (Met) to mycelial culture medium increased the ERG contents in most mushroom species tested, indicating that Met is a good additive to enhance the ERG levels in a variety of mushroom species. Taking these results into consideration, we suggest that the addition of Met to the mycelial culture medium is an efficient way to enhance the antioxidant properties in economically important mushroom species. PMID:23983506

  7. Improving monoterpene geraniol production through geranyl diphosphate synthesis regulation in Saccharomyces cerevisiae.

    PubMed

    Zhao, Jianzhi; Bao, Xiaoming; Li, Chen; Shen, Yu; Hou, Jin

    2016-05-01

    Monoterpenes have wide applications in the food, cosmetics, and medicine industries and have recently received increased attention as advanced biofuels. However, compared with sesquiterpenes, monoterpene production is still lagging in Saccharomyces cerevisiae. In this study, geraniol, a valuable acyclic monoterpene alcohol, was synthesized in S. cerevisiae. We evaluated three geraniol synthases in S. cerevisiae, and the geraniol synthase Valeriana officinalis (tVoGES), which lacked a plastid-targeting peptide, yielded the highest geraniol production. To improve geraniol production, synthesis of the precursor geranyl diphosphate (GPP) was regulated by comparing three specific GPP synthase genes derived from different plants and the endogenous farnesyl diphosphate synthase gene variants ERG20 (G) (ERG20 (K197G) ) and ERG20 (WW) (ERG20 (F96W-N127W) ), and controlling endogenous ERG20 expression, coupled with increasing the expression of the mevalonate pathway by co-overexpressing IDI1, tHMG1, and UPC2-1. The results showed that overexpressing ERG20 (WW) and strengthening the mevalonate pathway significantly improved geraniol production, while expressing heterologous GPP synthase genes or down-regulating endogenous ERG20 expression did not show positive effect. In addition, we constructed an Erg20p(F96W-N127W)-tVoGES fusion protein, and geraniol production reached 66.2 mg/L after optimizing the amino acid linker and the order of the proteins. The best strain yielded 293 mg/L geraniol in a fed-batch cultivation, a sevenfold improvement over the highest titer previously reported in an engineered S. cerevisiae strain. Finally, we showed that the toxicity of geraniol limited its production. The platform developed here can be readily used to synthesize other monoterpenes.

  8. l-Ergothioneine improves the developmental potential of in vitro sheep embryos without influencing OCTN1-mediated cross-membrane transcript expression.

    PubMed

    Mishra, A; Reddy, I J; Dhali, A; Javvaji, P K

    2018-04-02

    SummaryThe objective of the study was to investigate the effect of l-ergothioneine (l-erg) (5 mM or 10 mM) supplementation in maturation medium on the developmental potential and OCTN1-dependant l-erg-mediated (10 mM) change in mRNA abundance of apoptotic (Bcl2, Bax, Casp3 and PCNA) and antioxidant (GPx, SOD1, SOD2 and CAT) genes in sheep oocytes and developmental stages of embryos produced in vitro. Oocytes matured with l-erg (10 mM) reduced their embryo toxicity by decreasing intracellular ROS and increasing intracellular GSH in matured oocytes that in turn improved developmental potential, resulting in significantly (P < 0.05) higher percentages of cleavage (53.72% vs 38.86, 46.56%), morulae (34.36% vs 20.62, 25.84%) and blastocysts (14.83% vs 6.98, 9.26%) compared with other lower concentrations (0 mM and 5 mM) of l-erg without change in maturation rate. l-Erg (10 mM) treatment did not influence the mRNA abundance of the majority of apoptotic and antioxidant genes studied in the matured oocytes and developmental stages of embryo. A gene expression study found that the SLC22A4 gene that encodes OCTN1, an integral membrane protein and specific transporter of l-erg was not expressed in oocytes and developmental stages of embryos. Therefore it was concluded from the study that although there was improvement in the developmental potential of sheep embryos by l-erg supplementation in maturation medium, there was no change in the expression of the majority of the genes studied due to the absence of the SLC22A4 gene in oocytes and embryos that encode OCTN1, which is responsible for transportation of l-erg across the membrane to alter gene expression.

  9. PTEN Loss as Determined by Clinical-grade Immunohistochemistry Assay Is Associated with Worse Recurrence-free Survival in Prostate Cancer.

    PubMed

    Lotan, Tamara L; Wei, Wei; Morais, Carlos L; Hawley, Sarah T; Fazli, Ladan; Hurtado-Coll, Antonio; Troyer, Dean; McKenney, Jesse K; Simko, Jeffrey; Carroll, Peter R; Gleave, Martin; Lance, Raymond; Lin, Daniel W; Nelson, Peter S; Thompson, Ian M; True, Lawrence D; Feng, Ziding; Brooks, James D

    2016-06-01

    PTEN is the most commonly deleted tumor suppressor gene in primary prostate cancer (PCa) and its loss is associated with poor clinical outcomes and ERG gene rearrangement. We tested whether PTEN loss is associated with shorter recurrence-free survival (RFS) in surgically treated PCa patients with known ERG status. A genetically validated, automated PTEN immunohistochemistry (IHC) protocol was used for 1275 primary prostate tumors from the Canary Foundation retrospective PCa tissue microarray cohort to assess homogeneous (in all tumor tissue sampled) or heterogeneous (in a subset of tumor tissue sampled) PTEN loss. ERG status as determined by a genetically validated IHC assay was available for a subset of 938 tumors. Associations between PTEN and ERG status were assessed using Fisher's exact test. Kaplan-Meier and multivariate weighted Cox proportional models for RFS were constructed. When compared to intact PTEN, homogeneous (hazard ratio [HR] 1.66, p = 0.001) but not heterogeneous (HR 1.24, p = 0.14) PTEN loss was significantly associated with shorter RFS in multivariate models. Among ERG-positive tumors, homogeneous (HR 3.07, p < 0.0001) but not heterogeneous (HR 1.46, p = 0.10) PTEN loss was significantly associated with shorter RFS. Among ERG-negative tumors, PTEN did not reach significance for inclusion in the final multivariate models. The interaction term for PTEN and ERG status with respect to RFS did not reach statistical significance ( p = 0.11) for the current sample size. These data suggest that PTEN is a useful prognostic biomarker and that there is no statistically significant interaction between PTEN and ERG status for RFS. We found that loss of the PTEN tumor suppressor gene in prostate tumors as assessed by tissue staining is correlated with shorter time to prostate cancer recurrence after radical prostatectomy.

  10. In Vitro Cardiovascular Effects of Dihydroartemisin-Piperaquine Combination Compared with Other Antimalarials

    PubMed Central

    Crumb, William; Pace, Silvia; Ubben, David; Wible, Barb; Yan, Gan-Xin; Funck-Brentano, Christian

    2012-01-01

    The in vitro cardiac properties of dihydroartemisinin (DHA) plus piperaquine phosphate (PQP) were compared with those of other antimalarial compounds. Results with antimalarial drugs, chosen on the basis of their free therapeutic maximum concentration in plasma (Cmax), were expressed as the fold of that particular effect with respect to their Cmax. The following tests were used at 37°C: hERG (human ether-à-go-go-related gene) blockade and trafficking, rabbit heart ventricular preparations, and sodium and slow potassium ion current interference (INa and IKs, respectively). Chloroquine, halofantrine, mefloquine, and lumefantrine were tested in the hERG studies, but only chloroquine, dofetilide, lumefantrine, and the combination of artemether-lumefantrine were used in the rabbit heart ventricular preparations, hERG trafficking studies, and INa and IKs analyses. A proper reference was used in each test. In hERG studies, the high 50% inhibitory concentration (IC50) of halofantrine, which was lower than its Cmax, was confirmed. All the other compounds blocked hERG, with IC50s ranging from 3- to 30-fold their Cmaxs. In hERG trafficking studies, the facilitative effects of chloroquine at about 30-fold its Cmax were confirmed and DHA blocked it at a concentration about 300-fold its Cmax. In rabbit heart ventricular preparations, dofetilide, used as a positive control, revealed a high risk of torsades de pointes, whereas chloroquine showed a medium risk. Neither DHA-PQP nor artemether-lumefantrine displayed an in vitro signal for a significant proarrhythmic risk. Only chloroquine blocked the INa ion current and did so at about 30-fold its Cmax. No effect on IKs was detected. In conclusion, despite significant hERG blockade, DHA-PQP and artemether-lumefantrine do not appear to induce potential torsadogenic effects in vitro, affect hERG trafficking, or block sodium and slow potassium ion currents. PMID:22391528

  11. Molecular basis and drug sensitivity of the delayed rectifier (IKr) in the fish heart.

    PubMed

    Hassinen, Minna; Haverinen, Jaakko; Vornanen, Matti

    2015-01-01

    Fishes are increasingly used as models for human cardiac diseases, creating a need for a better understanding of the molecular basis of fish cardiac ion currents. To this end we cloned KCNH6 channel of the crucian carp (Carassius carassius) that produces the rapid component of the delayed rectifier K(+) current (IKr), the main repolarising current of the fish heart. KCNH6 (ccErg2) was the main isoform of the Kv11 potassium channel family with relative transcript levels of 98.9% and 99.6% in crucian carp atrium and ventricle, respectively. KCNH2 (ccErg1), an orthologue to human cardiac Erg (Herg) channel, was only slightly expressed in the crucian carp heart. The native atrial IKr and the cloned ccErg2 were inhibited by similar concentrations of verapamil, terfenadine and KB-R7943 (P>0.05), while the atrial IKr was about an order of magnitude more sensitive to E-4031 than ccErg2 (P<0.05) suggesting that some accessory β-subunits may be involved. Sensitivity of the crucian carp atrial IKr to E-4031, terfenadine and KB-R7943 was similar to what has been reported for the Herg channel. In contrast, the sensitivity of the crucian carp IKr to verapamil was approximately 30 times higher than the previously reported values for the Herg current. In conclusion, the cardiac IKr is produced by non-orthologous gene products in fish (Erg2) and mammalian hearts (Erg1) and some marked differences exist in drug sensitivity between fish and mammalian Erg1/2 which need to be taken into account when using fish heart as a model for human heart. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Pattern-reversal electroretinograms in unilateral glaucoma.

    PubMed

    Wanger, P; Persson, H E

    1983-06-01

    Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded from 11 patients with unilateral glaucoma. All glaucomatous eyes had reduced amplitudes both compared to the opposite eye in the same patient and to reference values. In 10 of the 11 cases this reduction was below the level of normal variation. The difference in pattern-reversal ERG amplitude means from glaucomatous and opposite eyes was statistically significant. No differences were observed in flash ERGs or OPs. The histopathologic correlate to the visual field defects in glaucoma is retinal ganglion cell degeneration. The present electrophysiologic findings support the view, based on results from animal experiments, that the pattern-reversal ERG reflects ganglion cell activity.

  13. A search for X-ray emission from a nearby pulsar - PSR 1929 + 10

    NASA Technical Reports Server (NTRS)

    Alpar, A.; Brinkmann, W.; Oegelman, H.; Kiziloglu, U.; Pines, D.

    1987-01-01

    Observations of the radio pulsar PSR 1929 + 10 with the Exosat observatory are reported. A 2 sigma upper limit of 0.0005 cts/s was obtained in the 0.04-2.4 keV range, which translates into a luminosity upper limit of 2 x 10 to the 29th erg/s for a power-law source with photon number index 1-3, and a luminosity upper limit of 10 to the 30th erg/s corresponding to a temperature of 190,000 K for a blackbody with radius 10 km. The implications of these upper limits for various models and their compatibility with the positive detection of this source by the Einstein Observatory are discussed.

  14. The Great Pretenders Among the ULX Class

    NASA Technical Reports Server (NTRS)

    Christodoulou, Dimitris M.; Laycock, Silas G. T.; Kazanas, Demosthenes; Cappallo, Rigel; Contopoulos, Ioannis

    2017-01-01

    The recent discoveries of pulsed X-ray emission from three ultraluminous X-ray (ULX) sources have finally enabled us to recognize a subclass within the ULX class: the great pretenders, neutron stars (NSs) that appear to emit X-ray radiation at isotropic luminosities Lx = 7 x 10(exp 39) erg/s - 1 x 10(exp 41) erg/s only because their emissions are strongly beamed toward our direction and our sight lines are offset by only a few degrees from their magnetic-dipole axes. The three known pretenders appear to be stronger emitters than the presumed black holes of the ULX class, such as Holmberg II & IX X-1, IC10 X-1 and NGC 300 X-1. For these three NSs, we have adopted a single reasonable assumption, that their brightest observed outbursts unfold at the Eddington rate, and we have calculated both their propeller states and their surface magnetic-field magnitudes. We find that the results are not at all different from those recently obtained for the Magellanic Be/X-ray pulsars: the three NSs reveal modest magnetic fields of about 0.3 - 0.4 TG and beamed propeller-line X-ray luminosities of approx. 10(exp 36) - 10(exp 37) erg/s, substantially below the Eddington limit.

  15. Effect of anoxia on the electroretinogram of three anoxia-tolerant vertebrates.

    PubMed

    Stensløkken, Kåre-Olav; Milton, Sarah L; Lutz, Peter L; Sundin, Lena; Renshaw, Gillian M C; Stecyk, Jonathan A W; Nilsson, Göran E

    2008-08-01

    To survive anoxia, neural ATP levels have to be defended. Reducing electrical activity, which accounts for 50% or more of neural energy consumption, should be beneficial for anoxic survival. The retina is a hypoxia sensitive part of the central nervous system. Here, we quantify the in vivo retinal light response (electroretinogram; ERG) in three vertebrates that exhibit varying degrees of anoxia tolerance: freshwater turtle (Trachemys scripta), epaulette shark (Hemiscyllium ocellatum) and leopard frog (Rana pipiens). A virtually total suppression of ERG in anoxia, probably resulting in functional blindness, has previously been seen in the extremely anoxia-tolerant crucian carp (Carassius carassius). Surprisingly, the equally anoxia-tolerant turtle, which strongly depresses brain and whole-body metabolism during anoxia, exhibited a relatively modest anoxic reduction in ERG: the combined amplitude of turtle ERG waves was reduced by approximately 50% after 2 h. In contrast, the shark b-wave amplitude practically disappeared after 30 min of severe hypoxia, and the frog b-wave was decreased by approximately 75% after 40 min in anoxia. The specific A(1) adenosine receptor antagonist CPT significantly delayed the suppression of turtle ERG, while the hypoxic shark ERG was unaffected by the non-specific adenosine receptor antagonist aminophylline, suggesting adenosinergic involvement in turtle but not in shark.

  16. Kassiopeia: a modern, extensible C++ particle tracking package

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Furse, Daniel; Groh, Stefan; Trost, Nikolaus

    The Kassiopeia particle tracking framework is an object-oriented software package using modern C++ techniques, written originally to meet the needs of the KATRIN collaboration. Kassiopeia features a new algorithmic paradigm for particle tracking simulations which targets experiments containing complex geometries and electromagnetic fields, with high priority put on calculation efficiency, customizability, extensibility, and ease-of-use for novice programmers. To solve Kassiopeia's target physics problem the software is capable of simulating particle trajectories governed by arbitrarily complex differential equations of motion, continuous physics processes that may in part be modeled as terms perturbing that equation of motion, stochastic processes that occur inmore » flight such as bulk scattering and decay, and stochastic surface processes occurring at interfaces, including transmission and reflection effects. This entire set of computations takes place against the backdrop of a rich geometry package which serves a variety of roles, including initialization of electromagnetic field simulations and the support of state-dependent algorithm-swapping and behavioral changes as a particle's state evolves. Thanks to the very general approach taken by Kassiopeia it can be used by other experiments facing similar challenges when calculating particle trajectories in electromagnetic fields. It is publicly available at https://github.com/KATRIN-Experiment/Kassiopeia.« less

  17. Kassiopeia: a modern, extensible C++ particle tracking package

    DOE PAGES

    Furse, Daniel; Groh, Stefan; Trost, Nikolaus; ...

    2017-05-16

    The Kassiopeia particle tracking framework is an object-oriented software package using modern C++ techniques, written originally to meet the needs of the KATRIN collaboration. Kassiopeia features a new algorithmic paradigm for particle tracking simulations which targets experiments containing complex geometries and electromagnetic fields, with high priority put on calculation efficiency, customizability, extensibility, and ease-of-use for novice programmers. To solve Kassiopeia's target physics problem the software is capable of simulating particle trajectories governed by arbitrarily complex differential equations of motion, continuous physics processes that may in part be modeled as terms perturbing that equation of motion, stochastic processes that occur inmore » flight such as bulk scattering and decay, and stochastic surface processes occurring at interfaces, including transmission and reflection effects. This entire set of computations takes place against the backdrop of a rich geometry package which serves a variety of roles, including initialization of electromagnetic field simulations and the support of state-dependent algorithm-swapping and behavioral changes as a particle's state evolves. Thanks to the very general approach taken by Kassiopeia it can be used by other experiments facing similar challenges when calculating particle trajectories in electromagnetic fields. It is publicly available at https://github.com/KATRIN-Experiment/Kassiopeia.« less

  18. Kassiopeia: a modern, extensible C++ particle tracking package

    NASA Astrophysics Data System (ADS)

    Furse, Daniel; Groh, Stefan; Trost, Nikolaus; Babutzka, Martin; Barrett, John P.; Behrens, Jan; Buzinsky, Nicholas; Corona, Thomas; Enomoto, Sanshiro; Erhard, Moritz; Formaggio, Joseph A.; Glück, Ferenc; Harms, Fabian; Heizmann, Florian; Hilk, Daniel; Käfer, Wolfgang; Kleesiek, Marco; Leiber, Benjamin; Mertens, Susanne; Oblath, Noah S.; Renschler, Pascal; Schwarz, Johannes; Slocum, Penny L.; Wandkowsky, Nancy; Wierman, Kevin; Zacher, Michael

    2017-05-01

    The Kassiopeia particle tracking framework is an object-oriented software package using modern C++ techniques, written originally to meet the needs of the KATRIN collaboration. Kassiopeia features a new algorithmic paradigm for particle tracking simulations which targets experiments containing complex geometries and electromagnetic fields, with high priority put on calculation efficiency, customizability, extensibility, and ease-of-use for novice programmers. To solve Kassiopeia's target physics problem the software is capable of simulating particle trajectories governed by arbitrarily complex differential equations of motion, continuous physics processes that may in part be modeled as terms perturbing that equation of motion, stochastic processes that occur in flight such as bulk scattering and decay, and stochastic surface processes occurring at interfaces, including transmission and reflection effects. This entire set of computations takes place against the backdrop of a rich geometry package which serves a variety of roles, including initialization of electromagnetic field simulations and the support of state-dependent algorithm-swapping and behavioral changes as a particle’s state evolves. Thanks to the very general approach taken by Kassiopeia it can be used by other experiments facing similar challenges when calculating particle trajectories in electromagnetic fields. It is publicly available at https://github.com/KATRIN-Experiment/Kassiopeia.

  19. Characterization of 1577 primary prostate cancers reveals novel biological and clinicopathologic insights into molecular subtypes.

    PubMed

    Tomlins, Scott A; Alshalalfa, Mohammed; Davicioni, Elai; Erho, Nicholas; Yousefi, Kasra; Zhao, Shuang; Haddad, Zaid; Den, Robert B; Dicker, Adam P; Trock, Bruce J; DeMarzo, Angelo M; Ross, Ashley E; Schaeffer, Edward M; Klein, Eric A; Magi-Galluzzi, Cristina; Karnes, R Jeffrey; Jenkins, Robert B; Feng, Felix Y

    2015-10-01

    Prostate cancer (PCa) molecular subtypes have been defined by essentially mutually exclusive events, including ETS gene fusions (most commonly involving ERG) and SPINK1 overexpression. Clinical assessment may aid in disease stratification, complementing available prognostic tests. To determine the analytical validity and clinicopatholgic associations of microarray-based molecular subtyping. We analyzed Affymetrix GeneChip expression profiles for 1577 patients from eight radical prostatectomy cohorts, including 1351 cases assessed using the Decipher prognostic assay (GenomeDx Biosciences, San Diego, CA, USA) performed in a laboratory with Clinical Laboratory Improvements Amendment certification. A microarray-based (m-) random forest ERG classification model was trained and validated. Outlier expression analysis was used to predict other mutually exclusive non-ERG ETS gene rearrangements (ETS(+)) or SPINK1 overexpression (SPINK1(+)). Associations with clinical features and outcomes by multivariate logistic regression analysis and receiver operating curves. The m-ERG classifier showed 95% accuracy in an independent validation subset (155 samples). Across cohorts, 45% of PCas were classified as m-ERG(+), 9% as m-ETS(+), 8% as m-SPINK1(+), and 38% as triple negative (m-ERG(-)/m-ETS(-)/m-SPINK1(-)). Gene expression profiling supports three underlying molecularly defined groups: m-ERG(+), m-ETS(+), and m-SPINK1(+)/triple negative. On multivariate analysis, m-ERG(+) tumors were associated with lower preoperative serum prostate-specific antigen and Gleason scores, but greater extraprostatic extension (p<0.001). m-ETS(+) tumors were associated with seminal vesicle invasion (p=0.01), while m-SPINK1(+)/triple negative tumors had higher Gleason scores and were more frequent in Black/African American patients (p<0.001). Clinical outcomes were not significantly different among subtypes. A clinically available prognostic test (Decipher) can also assess PCa molecular subtypes

  20. Novel Nomogram That Predicts Aggressive Disease and Treatment Failure Among African-American Men with Prostate Cancer

    DTIC Science & Technology

    2014-10-01

    and 55 AA men within the SCORE database. To date, 6 biomarkers have been analyzed including TMPRSS2-ERG, AMACR, PSMA , RB, c- Myc, and AR. We...analyzed so far including TMPRSS2-ERG, AMACR, PSMA , RB, c-Myc, and AR. In this cohort we observed statistically significant differences in marker...clinical practice. Not yet addressed Conclusion: Of the 20 biomarkers selected, six have been interrogated by IHC including TMPRSS2-ERG, AMACR, PSMA

  1. Abnormal electroretinogram associated with developmental brain anomalies.

    PubMed Central

    Cibis, G W; Fitzgerald, K M

    1995-01-01

    PURPOSE: We have encountered abnormal ERGs associated with optic nerve hypoplasia, macular, optic nerve and chorioretinal colobomata and developmental brain anomalies. Brain anomalies include cortical dysgenesis, lissencephaly, porencephaly, cerebellar and corpus callosum hypoplasia. We describe six exemplar cases. METHODS: Scotopic and photopic ERGs adherent to international standards were performed as well as photopic ERGs to long-duration stimuli. CT or MRI studies were also done. The ERGs were compared to age-matched normal control subjects. RESULTS: ERG changes include reduced amplitude b-waves to blue and red stimuli under scotopic testing conditions. Implicit times were often delayed. The photopic responses also showed reduced amplitude a- and b-waves with implicit time delays. The long-duration photopic ERG done in one case shows attenuation of both ON- and OFF-responses. CONCLUSIONS: Common underlying developmental genetic or environmental unifying casualties are speculated to be at fault in causing these cases of associated retinal and brain abnormalities. No single etiology is expected. Multiple potential causes acting early in embryogenesis effecting neuronal induction, migration and differentiation are theorized. These occur at a time when brain and retinal cells are sufficiently undifferentiated to be similarly effected. We call these cases examples of Brain Retina Neuroembryodysgenesis (BRNED). Homeobox and PAX genes with global neuronal developmental influences are gene candidates to unify the observed disruption of brain and retinal cell development. The ERG can provide a valuable clinical addition in understanding and ultimately classifying these disorders. Images FIGURE 1 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 PMID:8719676

  2. The Type and Impact of Evidence Review Group Exploratory Analyses in the NICE Single Technology Appraisal Process.

    PubMed

    Carroll, Christopher; Kaltenthaler, Eva; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2017-06-01

    As part of the UK National Institute for Health and Care Excellence (NICE) single technology appraisal process, independent evidence review groups (ERGs) critically appraise a company's submission relating to a specific technology and indication. To explore the type of additional exploratory analyses conducted by ERGs and their impact on the recommendations made by NICE. The 100 most recently completed single technology appraisals with published guidance were selected for inclusion. A content analysis of relevant documents was undertaken to identify and extract relevant data, and narrative synthesis was used to rationalize and present these data. The types of exploratory analysis conducted in relation to companies' models were fixing errors, addressing violations, addressing matters of judgment, and the provision of a new, ERG-preferred base case. Ninety-three of the 100 ERG reports contained at least one of these analyses. The most frequently reported type of analysis in these 93 ERG reports related to the category "Matters of judgment," which was reported in 83 reports (89%). At least one of the exploratory analyses conducted and reported by an ERG is mentioned in 97% of NICE appraisal consultation documents and 94% of NICE final appraisal determinations, and had a clear influence on recommendations in 72% of appraisal consultation documents and 47% of final appraisal determinations. These results suggest that the additional analyses undertaken by ERGs in the appraisal of company submissions are highly influential in the policy-making and decision-making process. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  3. The plasma wave experiment (PWE) on board the Arase (ERG) Satellite Initial results and collaboration with the ground network stations and Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Kasahara, Y.; Matsuda, S.; Kasaba, Y.; Kojima, H.; Tsuchiya, F.; Kumamoto, A.; Ozaki, M.; Yagitani, S.; Ishisaka, K.; Miyoshi, Y.; Hikishima, M.; Kitahara, M.; Katoh, Y.; Ota, M.; Kurita, S.; Shoji, M.; Imachi, T.; Teramoto, M.; Matsuoka, A.; Shinohara, I.; Hosokawa, K.; Ogawa, Y.; Shiokawa, K.; Kadokura, A.; Wygant, J. R.; Kletzing, C.

    2017-12-01

    The ERG (Exploration of energization and Radiation in Geospace) project is a mission to study acceleration and loss mechanisms of relativistic electrons around the Earth. To achieve comprehensive observations of plasma/particles, fields, and waves, the Arase satellite was launched on December 20, 2016. The Plasma Wave Experiment (PWE) is one of scientific instruments on board Arase. It measures electric field from DC to 10 MHz by the wire-probe antennas (WPT), and magnetic field from a few Hz to 100 kHz by the magnetic search coils (MSC). Three kinds of receivers are implemented in the PWE; EFD (Electric Field Detector), OFA/WFC (Onboard Frequency Analyzer and Waveform Capture), and HFA (High Frequency Analyzer). Several kinds of operational modes are implemented in the PWE, and the telemetry data consists of several kinds of data such as power spectrum, waveform, spectral matrix and DC E-field. The Arase has started nominal scientific operation in March 2017. Varieties of wave phenomena such as chorus, EMIC, and lightning whistlers have been successfully observed by the PWE. The wave activities are sometimes correlated with drastic variation of electron density derived from UHR frequency along the trajectory. We have also conducted cooperative observations with the ground-based stations, Van Allen Probes and the other satellites in the magnetosphere. During these conjunction periods, we intensively conducted the PWE burst mode operations, by which waveforms were continuously captured and once stored in the mission data recorder (MDR). The data stored in the MDP were selected and downloaded to the tracking stations according to the decision of the stakeholders of the campaign observation. In the presentation, we introduce the initial observation results of the PWE as well as quick report on the conjunction studies with the ground network stations and Van Allen Probes. Acknowledgements: We are greatly indebted to Mitsubishi Heavy Industries Ltd. for their

  4. Petroleum Independence: A Business Case and Strategy

    DTIC Science & Technology

    2006-04-14

    examples of this are the OPEC increases in 1973-74, Iranian Revolution of 1979, 1990 Iraqi invasion of Kuwait, and the Katrina hurricane disaster in 2005...retreat of glaciers.88 More hurricanes , droughts, and tropical diseases are likely caused by the fact that our last decade was reported as the hottest in...filelibrary/ Katrin aSlides.pdf ; Internet; accessed on December 7, 2005. Economic 37 lower-priced energy, and improved energy efficiencies. Regardless of

  5. Education and Training Issues Related to Major Disasters

    DTIC Science & Technology

    2005-11-04

    Mississippi that were affected by Hurricane Katrine would be permitted to reduce their academic year from 30 weeks of instructional time to 26 weeks... hurricanes . In addition, it is estimated that approximately 30 institutions of higher education (IHEs) in the affected areas have been severely damaged...of Hurricanes Katrina and Rita on employment probably resulted in the loss of between 293,000 and 480,000 jobs. Many of these individuals will not

  6. Regulation of the Response to Radiotherapy and Hyperthermia in Prostate Cancer by the 26s Proteasome

    DTIC Science & Technology

    2003-04-01

    Didanosine had been used in 62.5% of patients with gynaecomastia compared with 44.3% of indi- Volker Paech, Thore Lorenzen, Ariane von Krosigk, viduals...without disease. Nelfinavir was given to 62.5% Katrin Graefe, Albrecht Stoehr and And as Plettenberg, of the individuals with gynaecomastia . but was...any. Gynaecomastia caused by HAART has been reported Received: 10 January 2002;’acc ted: 15 January 2002. for several drugs, e.g. efavirenz

  7. Very Luminous X-ray Point Sources in Starburst Galaxies

    NASA Astrophysics Data System (ADS)

    Colbert, E.; Heckman, T.; Ptak, A.; Weaver, K. A.; Strickland, D.

    Extranuclear X-ray point sources in external galaxies with luminosities above 1039.0 erg/s are quite common in elliptical, disk and dwarf galaxies, with an average of ~ 0.5 and dwarf galaxies, with an average of ~0.5 sources per galaxy. These objects may be a new class of object, perhaps accreting intermediate-mass black holes, or beamed stellar mass black hole binaries. Starburst galaxies tend to have a larger number of these intermediate-luminosity X-ray objects (IXOs), as well as a large number of lower-luminosity (1037 - 1039 erg/s) point sources. These point sources dominate the total hard X-ray emission in starburst galaxies. We present a review of both types of objects and discuss possible schemes for their formation.

  8. High-Speed Ultra-High-Resolution Optical Coherence Tomography Findings in Hydroxychloroquine Retinopathy

    PubMed Central

    Rodriguez-Padilla, Julio A.; Hedges, Thomas R.; Monson, Bryan; Srinivasan, Vivek; Wojtkowski, Maciej; Reichel, Elias; Duker, Jay S.; Schuman, Joel S.; Fujimoto, James G.

    2007-01-01

    Objectives To compare structural changes in the retina seen on high-speed ultra–high-resolution optical coherence tomography (hsUHR-OCT) with multifocal electroretinography (mfERG) and automated visual fields in patients receiving hydroxychloroquine. Methods Fifteen patients receiving hydroxychloroquine were evaluated clinically with hsUHR-OCT, mfERG, and automated visual fields. Six age-matched subjects were imaged with hsUHR-OCT and served as controls. Results Distinctive discontinuity of the perifoveal photoreceptor inner segment/outer segment junction and thinning of the outer nuclear layer were seen with hsUHR-OCT in patients with mild retinal toxic effects. Progression to complete loss of the inner segment/outer segment junction and hyperscattering at the outer segment level were seen in more advanced cases. The mfERG abnormalities correlated with the hsUHR-OCT findings. Asymptomatic patients had normal hsUHR-OCT and mfERG results. Conclusion Distinctive abnormalities in the perifoveal photoreceptor inner segment/outer segment junction were seen on hsUHR-OCT in patients receiving hydroxychloroquine who also were symptomatic and had abnormalities on automated visual fields and mfERG. PMID:17562988

  9. Neuroprotective Dose Response in RCS Rats Implanted with Microphotodiode Arrays

    PubMed Central

    Pardue, Machelle T.; Kim, Moon K.; Walker, Tiffany A.; Faulkner, Amanda E.; Chow, Alan Y.; Ciavatta, Vincent T.

    2012-01-01

    Purpose Neuropreservation of retinal function and structure in RCS rats following implantation of a microphotodiode array (MPA) has been shown in previous studies(Pardue et al. 2005a; Pardue et al. 2005b). Since microphotodiodes produce electrical currents in proportion to the intensity of incident light, increased light exposure may result in greater neuroprotective effects. Our previous studies suggested that the frequency of light exposure to electroretinogram (ERG) flash stimuli might provide increased neuroprotection. Thus, in this study, we examined the dose response of subretinal electrical stimulation by exposing RCS rats implanted with MPAs to variable durations and combinations of two different lighting regimens: pulsing incandescent bulbs and xenon stimuli from an ERG Ganzfeld. While incandescent light regimens did not produce any significant differences in ERG function, we found significantly greater dark-adapted ERG b-wave amplitudes in RCS rats that received weekly versus biweekly ERGs over the course of 8 weeks of follow-up. These results suggest that subretinal electrical stimulation may be optimized to produce greater neuroprotective effects by dosing with periodic higher current. PMID:22183323

  10. One-step electrodeposition of graphene loaded nickel oxides nanoparticles for acetaminophen detection.

    PubMed

    Liu, Gui-Ting; Chen, Hui-Fen; Lin, Guo-Ming; Ye, Ping-ping; Wang, Xiao-Ping; Jiao, Ying-Zhi; Guo, Xiao-Yu; Wen, Ying; Yang, Hai-Feng

    2014-06-15

    An electrochemical sensor of acetaminophen (AP) based on electrochemically reduced graphene (ERG) loaded nickel oxides (Ni2O3-NiO) nanoparticles coated onto glassy carbon electrode (ERG/Ni2O3-NiO/GCE) was prepared by a one-step electrodeposition process. The as-prepared electrode was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The electrocatalytic properties of ERG/Ni2O3-NiO modified glassy carbon electrode toward the oxidation of acetaminophen were analyzed via cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrodes of Ni2O3-NiO/GCE, ERG/GCE, and Ni2O3-NiO deposited ERG/GCE were fabricated for the comparison and the catalytic mechanism understanding. The studies showed that the one-step prepared ERG/Ni2O3-NiO/GCE displayed the highest electro-catalytic activity, attributing to the synergetic effect derived from the unique composite structure and physical properties of nickel oxides nanoparticles and graphene. The low detection limit of 0.02 μM (S/N=3) with the wide linear detection range from 0.04 μM to 100 μM (R=0.998) was obtained. The resulting sensor was successfully used to detect acetaminophen in commercial pharmaceutical tablets and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Multifocal and full-field electroretinogram changes associated with color-vision loss in mercury vapor exposure.

    PubMed

    Ventura, Dora F; Costa, Marcelo T V; Costa, Marcelo F; Berezovsky, Adriana; Salomão, Solange R; Simões, Ana Luíza; Lago, Marcos; Pereira, Luiz H M Canto; Faria, Marcília A M; De Souza, John M; Silveira, Luiz Carlos L

    2004-01-01

    We evaluated the color vision of mercury-contaminated patients and investigated possible retinal origins of losses using electroretinography. Participants were retired workers from a fluorescent lamp industry diagnosed with mercury contamination (n = 43) and age-matched controls (n = 21). Color discrimination was assessed with the Cambridge Colour Test (CCT). Retinal function was evaluated by using the ISCEV protocol for full-field electroretinography (full-field ERG), as well as by means of multifocal electroretinography (mfERG). Color-vision losses assessed by the CCT consisted of higher color-discrimination thresholds along the protan, deutan, and tritan axes and significantly larger discrimination ellipses in mercury-exposed patients compared to controls. Full-field ERG amplitudes from patients were smaller than those of the controls for the scotopic response b-wave, maximum response, sum of oscillatory potentials (OPs), 30-Hz flicker response, and light-adapted cone response. OP amplitudes measured in patients were smaller than those of controls for O2 and O3. Multifocal ERGs recorded from ten randomly selected patients showed smaller N1-P1 amplitudes and longer latencies throughout the 25-deg central field. Full-field ERGs showed that scotopic, photopic, peripheral, and midperipheral retinal functions were affected, and the mfERGs indicated that central retinal function was also significantly depressed. To our knowledge, this is the first demonstration of retinal involvement in visual losses caused by mercury toxicity.

  12. Simultaneous chromatic and luminance human electroretinogram responses.

    PubMed

    Parry, Neil R A; Murray, Ian J; Panorgias, Athanasios; McKeefry, Declan J; Lee, Barry B; Kremers, Jan

    2012-07-01

    The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats' ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing.

  13. Simultaneous chromatic and luminance human electroretinogram responses

    PubMed Central

    Parry, Neil R A; Murray, Ian J; Panorgias, Athanasios; McKeefry, Declan J; Lee, Barry B; Kremers, Jan

    2012-01-01

    The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats’ ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing. PMID:22586211

  14. The Emotional Resources Group: Provisional outcome data for a pilot six-session emotion regulation programme for secondary care.

    PubMed

    Bacon, Thomas; Doughty, Caitriona; Summers, Andrew; Wiffen, Benjamin; Stanley, Zoe; McAlpine, Susan

    2018-06-01

    To examine the effectiveness of a new, six-session emotion regulation group intervention designed for the secondary care setting: The Emotional Resources Group (ERG). In this pilot study, participants were recruited by referral from secondary care mental health services. Forty-seven individuals participated in the study. Participants who attended the ERG were compared on measures of emotion regulation, well-being, and self-efficacy, pre- and post-intervention. Intent-to-treat analyses indicated highly statistically significant improvements in measures of emotion regulation, well-being, and self-efficacy, accompanied by large effect sizes. In addition, improvements in emotion regulation produced good rates of both reliable and clinically significant change. The ERG may be an effective, brief intervention to improve emotion regulation in the secondary care setting, worthy of further evaluation. Clinical implications Emotion regulation may be an appropriate treatment target to improve well-being and self-efficacy in a transdiagnostic population. The ERG may be effective as a brief emotion regulation intervention for secondary care mental health settings. Outcomes of the ERG appear to be equivalent to other more intensive group-based emotion regulation interventions. The ERG's tailored design may be responsible for positive outcomes. Limitations There was a small sample size. There was no control group. There was no follow-up data. © 2018 The British Psychological Society.

  15. Multifocal electroretinogram and central visual field testing in central areolar choroidal dystrophy.

    PubMed

    Gundogan, Fatih Cakir; Dinç, Umut Asli; Erdem, Uzeyir; Ozge, Gokhan; Sobaci, Gungor

    2010-01-01

    To study multifocal electroretinogram (mfERG) and its relation to retinal sensitivity assessed by Humphrey visual field (HVF) analysis in central areolar choroidal dystrophy (CACD). Seven eyes of 4 patients with CACD and 15 normal control subjects were examined. mfERG and central 30/2 HVF were tested for each participant. Ring analysis in mfERG was evaluated. HVF results were evaluated in 5 concentric rings in order to compare the results to concentric ring analysis in mfERG. The differences between control subjects and patients were evaluated by Mann-Whitney U test and the correlations were assessed by Spearman test. Mean Snellen acuity was 0.49+/-0.10 in patients. HVF revealed central scotoma in 6 of 7 eyes (85.7%), whereas a paracentral scotoma extending to fixation point was detected in 1 eye. The retinal sensitivities in 5 concentric rings in HVF were significantly lower (p<0.001 for ring 1 to ring 4, and p=0.017 in ring 5) in CACD patients. Similarly, CACD patients had lower P1/N1 amplitudes (p<0.05) and delayed P1/N1 implicit times (p<0.05). In CACD, in the areas of scotoma detected by HVF, mfERG values were depressed. However, both mfERG and HVF abnormalities were found outside the areas of ophthalmoscopically normal retinal areas.

  16. Functional and Structural Findings of Neurodegeneration in Early Stages of Diabetic Retinopathy: Cross-sectional Analyses of Baseline Data of the EUROCONDOR Project.

    PubMed

    Santos, Ana Rita; Ribeiro, Luísa; Bandello, Francesco; Lattanzio, Rosangela; Egan, Catherine; Frydkjaer-Olsen, Ulrik; García-Arumí, José; Gibson, Jonathan; Grauslund, Jakob; Harding, Simon P; Lang, Gabriele E; Massin, Pascale; Midena, Edoardo; Scanlon, Peter; Aldington, Stephen J; Simão, Sílvia; Schwartz, Christian; Ponsati, Berta; Porta, Massimo; Costa, Miguel Ângelo; Hernández, Cristina; Cunha-Vaz, José; Simó, Rafael

    2017-09-01

    This cross-sectional study evaluated the relationship between 1 ) functional and structural measurements of neurodegeneration in the initial stages of diabetic retinopathy (DR) and 2 ) the presence of neurodegeneration and early microvascular impairment. We analyzed baseline data of 449 patients with type 2 diabetes enrolled in the European Consortium for the Early Treatment of Diabetic Retinopathy (EUROCONDOR) study (NCT01726075). Functional studies by multifocal electroretinography (mfERG) evaluated neurodysfunction, and structural measurements using spectral domain optical coherence tomography (SD-OCT) evaluated neurodegeneration. The mfERG P1 amplitude was more sensitive than the P1 implicit time and was lower in patients with Early Treatment of Diabetic Retinopathy Study (ETDRS) level 20-35 than in patients with ETDRS level <20 ( P = 0.005). In 58% of patients, mfERG abnormalities were present in the absence of visible retinopathy. Correspondence between SD-OCT thinning and mfERG abnormalities was shown in 67% of the eyes with ETDRS <20 and in 83% of the eyes with ETDRS level 20-35. Notably, 32% of patients with ETDRS 20-35 presented no abnormalities in mfERG or SD-OCT. We conclude that there is a link between mfERG and SD-OCT measurements that increases with the presence of microvascular impairment. However, a significant proportion of patients in our particular study population (ETDRS ≤35) had normal ganglion cell-inner plexiform layer thickness and normal mfERG findings. We raise the hypothesis that neurodegeneration may play a role in the pathogenesis of DR in many but not in all patients with type 2 diabetes. © 2017 by the American Diabetes Association.

  17. Myosin 6 is required for iris development and normal function of the outer retina.

    PubMed

    Samuels, Ivy S; Bell, Brent A; Sturgill-Short, Gwen; Ebke, Lindsey A; Rayborn, Mary; Shi, Lanying; Nishina, Patsy M; Peachey, Neal S

    2013-11-01

    To determine the molecular basis and the pathologic consequences of a chemically induced mutation in the translational vision research models 89 (tvrm89) mouse model with ERG defects. Mice from a G3 N-ethyl-N-nitrosourea mutagenesis program were screened for behavioral abnormalities and defects in retinal function by ERGs. The chromosomal position for the recessive tvrm89 mutation was determined in a genome-wide linkage analysis. The critical region was refined, and candidate genes were screened by direct sequencing. The tvrm89 phenotype was characterized by circling behavior, in vivo ocular imaging, detailed ERG-based studies of the retina and RPE, and histological analysis of these structures. The tvrm89 mutation was localized to a region on chromosome 9 containing Myo6. Sequencing identified a T→C point mutation in the codon for amino acid 480 in Myo6 that converts a leucine to a proline. This mutation does not confer a loss of protein expression levels; however, mice homozygous for the Myo6(tvrm89) mutation display an abnormal iris shape and attenuation of both strobe-flash ERGs and direct-current ERGs by 4 age weeks, neither of which is associated with photoreceptor loss. The tvrm89 phenotype mimics that reported for Myosin6-null mice, suggesting that the mutation confers a loss of myosin 6 protein function. The observation that homozygous Myo6(tvrm89) mice display reduced ERG a-wave and b-wave components, as well as components of the ERG attributed to RPE function, indicates that myosin 6 is necessary for the generation of proper responses of the outer retina to light.

  18. Spectroscopic and Photometric Observations of a Five-Magnitude Flare Event on UV Ceti

    DTIC Science & Technology

    1992-05-12

    bremsstrahlung spectrum. The energy emitted by the flare in the U band is approxi- mately 5.OX 10oi ergs. The corresotonding total flare energy in white !ight is...temporal resolutions. A strong violet continuum is seen which cannot be reproduced solely with a thermal bremsstrahlung spectrum. The energy emitted by...the flare in the U band is approxi- mately 5.0 X 1031 ergs. The corresponding total flare energy in white light is estimated to be 1.2X 1032 ergs

  19. Electrophysiological assessment for early detection of retinal dysfunction in β-thalassemia major patients.

    PubMed

    Dettoraki, Maria; Kattamis, Antonis; Ladas, Ioannis; Maragkos, Konstantinos; Koutsandrea, Chryssanthi; Chatzistefanou, Klio; Laios, Konstantinos; Brouzas, Dimitrios; Moschos, Marilita M

    2017-07-01

    The purpose of this study was to assess the role of various diagnostic tests in early detection of retinal changes in β-thalassemia major patients. Thirty-eight visually asymptomatic β-thalassemia major patients receiving regular blood transfusions and iron-chelation therapy with deferoxamine (group A, n = 13), deferasirox (group B, n = 11) or deferoxamine with deferiprone (group C, n = 14) and fourteen age- and sex- matched healthy individuals were included in the study. All participants underwent ophthalmoscopy, full-field electroretinography (ERG), visual evoked potentials (VEP), multifocal electroretinography (mfERG), fundus autofluorescence (FAF) imaging and optical coherence tomography (OCT) scans. Retinal pigment epithelium changes were present in two cases. Scotopic ERG demonstrated decreased a-wave amplitude in groups A, B and C (p = 0.03, p = 0.002 and p = 0.002, respectively) and decreased b-wave amplitude in groups B and C (p = 0.002 and p = 0.01, respectively) compared to controls. Photopic ERG showed delayed b-wave latency in groups A and C (p = 0.03 and p = 0.03, respectively) ERG maximal combined response and VEP response did not differ between groups. MfERG showed reduced retinal response density in ring 1 in groups A, B, C (p < 0.001, p < 0.001, p = 0.001, respectively) and ring 2 in group B (p = 0.02) and delayed latency in ring 5 in groups A and B (p = 0.04 and p = 0.04, respectively). Abnormal FAF images appeared in three cases and OCT abnormalities in one case, whereas no changes were observed in controls (p = 0.55 and p = 1.00, respectively). Full-field ERG and mfERG are more sensitive tools for detecting early retinal changes in β-thalassemia patients compared with ophthalmoscopy, VEP, FAF imaging and OCT scans.

  20. PTEN Loss as Determined by Clinical-grade Immunohistochemistry Assay Is Associated with Worse Recurrence-free Survival in Prostate Cancer

    PubMed Central

    Lotan, Tamara L.; Wei, Wei; Morais, Carlos L.; Hawley, Sarah T.; Fazli, Ladan; Hurtado-Coll, Antonio; Troyer, Dean; McKenney, Jesse K.; Simko, Jeffrey; Carroll, Peter R.; Gleave, Martin; Lance, Raymond; Lin, Daniel W.; Nelson, Peter S.; Thompson, Ian M.; True, Lawrence D.; Feng, Ziding; Brooks, James D.

    2015-01-01

    Background PTEN is the most commonly deleted tumor suppressor gene in primary prostate cancer (PCa) and its loss is associated with poor clinical outcomes and ERG gene rearrangement. Objective We tested whether PTEN loss is associated with shorter recurrence-free survival (RFS) in surgically treated PCa patients with known ERG status. Design, setting, and participants A genetically validated, automated PTEN immunohistochemistry (IHC) protocol was used for 1275 primary prostate tumors from the Canary Foundation retrospective PCa tissue microarray cohort to assess homogeneous (in all tumor tissue sampled) or heterogeneous (in a subset of tumor tissue sampled) PTEN loss. ERG status as determined by a genetically validated IHC assay was available for a subset of 938 tumors. Outcome measurements and statistical analysis Associations between PTEN and ERG status were assessed using Fisher’s exact test. Kaplan-Meier and multivariate weighted Cox proportional models for RFS were constructed. Results and limitations When compared to intact PTEN, homogeneous (hazard ratio [HR] 1.66, p = 0.001) but not heterogeneous (HR 1.24, p = 0.14) PTEN loss was significantly associated with shorter RFS in multivariate models. Among ERG-positive tumors, homogeneous (HR 3.07, p < 0.0001) but not heterogeneous (HR 1.46, p = 0.10) PTEN loss was significantly associated with shorter RFS. Among ERG-negative tumors, PTEN did not reach significance for inclusion in the final multivariate models. The interaction term for PTEN and ERG status with respect to RFS did not reach statistical significance (p = 0.11) for the current sample size. Conclusions These data suggest that PTEN is a useful prognostic biomarker and that there is no statistically significant interaction between PTEN and ERG status for RFS. Patient summary We found that loss of the PTEN tumor suppressor gene in prostate tumors as assessed by tissue staining is correlated with shorter time to prostate cancer recurrence after radical

  1. France: Factors Shaping Foreign Policy, and Issues in U.S.-French Relations

    DTIC Science & Technology

    2006-01-03

    national governments to expend public funds on enhancing the competitiveness of key companies. See Bennhold, Katrin , “ Sarkozy Urges Europe to Forge...consternés par la fragilité de leur puissance,” Le Monde, Sept. 3, 2005, p. 3; “ Hurricane Katrina: French Assistance,” doc. supplied by French embassy, Sept...the United States as having feet of clay. Hurricane Katrina fueled this sentiment. The French media was both puzzled by and critical of the U.S

  2. Earth observations taken during the STS-103 mission

    NASA Image and Video Library

    1999-12-24

    STS103-710-084 (19-27 December 1999)--- One of the astronauts aboard the Earth-orbiting Space Shuttle Discovery used a handheld 70mm camera to photograph the great sand seas which occupy northern Algeria. They are Grand Erg Oriental (Eastern Sand Sea) and Grand Erg Occidental (Western Sand Sea). Both sand seas occupy depressions that are separated by a north-south rise called Mizab. Ergs are areas of large accumulations of sand that take the form of actively shifting dunes, fossilized dunes, or extensive sand sheets.

  3. Four peer reviews in support of the Tier 3 rulemaking ...

    EPA Pesticide Factsheets

    Peer review of ERG's KenCaryl (CO) estimated summer hot-soak distributions report in support of the Tier 3 rulemaking To peer review ERG's KenCaryl (CO) estimated summer hot-soak distributions report (for Tier 3 rulemaking)

  4. Characterization of 1,577 Primary Prostate Cancers Reveals Novel Biological and Clinicopathological Insights into Molecular Subtypes

    PubMed Central

    Tomlins, Scott A.; Alshalalfa, Mohammed; Davicioni, Elai; Erho, Nicholas; Yousefi, Kasra; Zhao, Shuang; Haddad, Zaid; Den, Robert B.; Dicker, Adam P.; Trock, Bruce; DeMarzo, Angelo; Ross, Ashley; Schaeffer, Edward M.; Klein, Eric A.; Magi-Galluzzi, Cristina; Karnes, Jeffery R.; Jenkins, Robert B.; Feng, Felix Y.

    2015-01-01

    Background Prostate cancer (PCa) molecular subtypes have been defined by essentially mutually exclusive events, including ETS gene fusions (most commonly involving ERG) and SPINK1 over-expression. Clinical assessment may aid in disease stratification, complementing available prognostic tests. Objective To determine the analytical validity and clinicopatholgical associations of microarray-based molecular subtyping. Design, Setting and Participants We analyzed Affymetrix GeneChip expression profiles for 1,577 patients from eight radical prostatectomy (RP) cohorts, including 1,351 cases assessed using the Decipher prognostic assay (performed in a CLIA-certified laboratory). A microarray-based (m-) random forest ERG classification model was trained and validated. Outlier expression analysis was used to predict other mutually exclusive non-ERG ETS gene rearrangements (ETS+) or SPINK1 over-expression (SPINK1+). Outcome Measurements Associations with clinical features and outcomes by multivariable logistic regression analysis and receiver operating curves. Results and Limitations The m-ERG classifier showed 95% accuracy in an independent validation subset (n=155 samples). Across cohorts, 45%, 9%, 8% and 38% of PCa were classified as m-ERG+, m-ETS+, m-SPINK1+, and triple negative (m-ERG−/m-ETS−/m-SPINK1−), respectively. Gene expression profiling supports three underlying molecularly defined groups (m-ERG+, m-ETS+ and m-SPINK1+/triple negative). On multivariable analysis, m-ERG+ tumors were associated with lower preoperative serum PSA and Gleason scores, but enriched for extraprostatic extension (p<0.001). m-ETS+ tumors were associated with seminal vesicle invasion (p=0.01), while m-SPINK1+/triple negative tumors had higher Gleason scores and were more frequent in Black/African American patients (p<0.001). Clinical outcomes were not significantly different between subtypes. Conclusions A clinically available prognostic test (Decipher) can also assess PCa molecular

  5. Ophthalmic Evaluation in Beta-Thalassemia.

    PubMed

    Merchant, Rashid H; Punde, Hrishikesh; Thacker, Neepa; Bhatt, Deepak

    2017-07-01

    To determine the association of ocular manifestations in beta-thalassemia with the patient's age, blood transfusion requirements, average serum ferritin and dose and duration of iron chelation therapy. Sixty multi-transfused beta thalassemia patients of 12 to 18 y of age on chelation therapy were included in this cross-sectional analysis. Structural and functional evaluation of the retina was done using Optical coherence tomography (OCT) and Electroretinography (ERG), including flash ERG and Pattern ERG (PERG). Routine ophthalmic examination and B scan of the eye was also done. Flash ERG a-waves and b-waves were recorded, however only a-wave amplitude was evaluated. Pattern ERG n35, n95 and p50 waves were recorded and p50 wave amplitude was evaluated. The a-wave on flash and p50 on pattern waves represent retinal photoreceptor epithelium (RPE) photoreceptor response, which is mainly affected in beta-thalassemia. Ocular changes were detected in 38.3% and a significant correlation was noted with increase in age (p = 0.045) but not with serum ferritin, transfusion requirements or chelation therapy. Refractive errors were found in 14 cases (23%), such as myopia with astigmatism in 13 (21.7%) and only myopia in 6 subjects (10%). OCT abnormality was noted in 1 patient (1.7%) who had thinning of central retina; right eye 132 μm and left eye 146 μm (n > 200 μm). Abnormalities were noted in a-wave amplitude on flash ERG in 20% of cases, while reduced p50 amplitude on PERG was noted in 15%. A significant correlation was noted between ocular findings and increase in age, but not with serum ferritin, transfusion requirements or chelation therapy. ERG appears to be a promising tool for screening patients with beta-thalassemia and can serve as a follow-up test for evaluating retinal function.

  6. Correlation between human ether‐a‐go‐go‐related gene channel inhibition and action potential prolongation

    PubMed Central

    Saxena, P; Hortigon‐Vinagre, M P; Beyl, S; Baburin, I; Andranovits, S; Iqbal, S M; Costa, A; IJzerman, A P; Kügler, P; Timin, E

    2017-01-01

    Background and Purpose Human ether‐a‐go‐go‐related gene (hERG; Kv11.1) channel inhibition is a widely accepted predictor of cardiac arrhythmia. hERG channel inhibition alone is often insufficient to predict pro‐arrhythmic drug effects. This study used a library of dofetilide derivatives to investigate the relationship between standard measures of hERG current block in an expression system and changes in action potential duration (APD) in human‐induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs). The interference from accompanying block of Cav1.2 and Nav1.5 channels was investigated along with an in silico AP model. Experimental Approach Drug‐induced changes in APD were assessed in hiPSC‐CMs using voltage‐sensitive dyes. The IC50 values for dofetilide and 13 derivatives on hERG current were estimated in an HEK293 expression system. The relative potency of each drug on APD was estimated by calculating the dose (D150) required to prolong the APD at 90% (APD90) repolarization by 50%. Key Results The D150 in hiPSC‐CMs was linearly correlated with IC50 of hERG current. In silico simulations supported this finding. Three derivatives inhibited hERG without prolonging APD, and these compounds also inhibited Cav1.2 and/or Nav1.5 in a channel state‐dependent manner. Adding Cav1.2 and Nav1.2 block to the in silico model recapitulated the direction but not the extent of the APD change. Conclusions and Implications Potency of hERG current inhibition correlates linearly with an index of APD in hiPSC‐CMs. The compounds that do not correlate have additional effects including concomitant block of Cav1.2 and/or Nav1.5 channels. In silico simulations of hiPSC‐CMs APs confirm the principle of the multiple ion channel effects. PMID:28681507

  7. Retinal cross talk in the mammalian visual system

    PubMed Central

    Tang, Xiaolan; Tzekov, Radouil

    2016-01-01

    The existence and functional relevance of efferent optic nerve fibers in mammals have long been debated. While anatomical evidence for cortico-retinal and retino-retinal projections is substantial, physiological evidence is lacking, as efferent fibers are few in number and are severed in studies of excised retinal tissue. Here we show that interocular connections contribute to retinal bioelectrical activity in adult mammals. Full-field flash electroretinograms (ERGs) were recorded from one or both eyes of Brown-Norway rats under dark-adapted (n = 16) and light-adapted (n = 11) conditions. Flashes were confined to each eye by an opaque tube that blocked stray light. Monocular flashes evoked a small (5–15 μV) signal in the nonilluminated eye, which was named “crossed ERG” (xERG). The xERG began under dark-adapted conditions with a positive (xP1) wave that peaked at 70–90 ms and ended with slower negative (xN1) and positive (xP2) waves from 200 to 400 ms. xN1 was absent under light-adapted conditions. Injection of tetrodotoxin in either eye (n = 15) eliminated the xERG. Intraocular pressure elevation of the illuminated eye (n = 6) had the same effect. The treatments also altered the ERG b-wave in both eyes, and the alterations correlated with xERG disappearance. Optic nerve stimulation (n = 3) elicited a biphasic compound action potential in the nonstimulated nerve with 10- to 13-ms latency, implying that the xERG comes from slow-conducting (W type) fibers. Monocular dye application (n = 7) confirmed the presence of retino-retinal ganglion cells in adult rats. We conclude that mammalian eyes communicate directly with each other via a handful of optic nerve fibers. The cross talk alters retinal activity in rats, and perhaps other animals. PMID:26984426

  8. Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery.

    PubMed

    Hoffman, Allison; Sisler, Steve; Pappania, Marie; Hsu, Kimberly; Ross, Maya; Ofri, Ron

    2018-05-01

    To determine whether pre-operative electroretinography (ERG) predicts postoperative vision in dogs undergoing retinal reattachment surgery (RRS). This 18-month prospective study recorded signalment, duration, cause, and extent of retinal detachment and pre-operative vision status. Rod and mixed rod-cone ERG responses were recorded prior to RRS. Referring veterinary ophthalmologists assessed vision 2 months postoperatively. Thirty dogs (40 affected eyes) aged 4 months to 12.1 years were included. The detachment extent was 150 ° -320 ° in 15 of 40 eyes, 360 ° in 24 of 40 eyes, and not recorded in one eye. Most dogs had a genetic predisposition for retinal detachment. Eight eyes of seven dogs had previous cataract surgery. Mean estimated duration of detachment prior to surgery was 24.5 ± 19.6 days. Pre-operatively, 34 of 40 eyes were blind, two of 40 eyes were sighted, and four of 40 eyes had severely diminished vision. Compared to normative ERG values in our clinics, pre-operative ERGs were classified as "normal" in five of 40 eyes, "attenuated" in seven of 40 eyes, and "flat" in 28 of 40 eyes. Following RRS, the retina was fully reattached in all operated eyes. Two-month postoperatively, 30 of 40 eyes had "normal" vision as defined by referring veterinary ophthalmologists, six of 40 eyes had "limited" or "diminished" vision and four of 40 eyes were blind. Normal vision was regained in 12 of 12 (100%) of eyes with normal or attenuated pre-operative ERG's, but only in 18 of 28 (64%) of eyes with flat pre-operative ERG 's (Linear-by-linear test, P = 0.029). A recordable pre-operative ERG, even if attenuated, is associated with return of vision in canine RRS patients, and is a favorable prognostic indicator. © 2017 American College of Veterinary Ophthalmologists.

  9. Evidence for a crucial modulating role of the sodium channel in the QTc prolongation related to antipsychotics.

    PubMed

    Silvestre, Jordi S; O'Neill, Michael F; Prous, Josep R

    2014-04-01

    Blockade of the cardiac hERG channel is recognized as the main mechanism underlying the QT prolongation induced by many classes of drugs, including antipsychotics. However, antipsychotics interact with a variety of other pharmacological targets that could also modulate cardiac function. The present study aims to identify those key factors involved in the QT prolongation induced by antipsychotics. The interactions of 28 antipsychotics were measured on a variety of pharmacological targets. Binding affinity (K(i)), functional channel blockade (IC₅₀), and the corresponding ratios to total and free plasma drug concentration were compared with the corrected QT changes (QTc) associated with the therapeutic use of these drugs by multivariable linear regression analysis to determine the best predictors of QTc. Besides confirming hERG as the primary predictor of QTc, all analyses consistently show the concomitant involvement of Na(V)1.5 channel as modulating factor of the QTc related to hERG blockade. In particular, the hERG/Na(V)1.5 ratio explains the 57% of the overall QTc variability associated with antipsychotics. Since it is known that inhibition of late I Na could offset the dysfunctional effects of hERG blockade, we hypothesize the inhibition of late I(Na) as a crucial compensatory mechanism of the QTc associated with antipsychotics and hence an important factor to consider concomitantly with hERG blockade to appraise the arrhythmogenic risk of these drugs more accurately.

  10. Transcriptional profiling analysis of Penicillium digitatum, the causal agent of citrus green mold, unravels an inhibited ergosterol biosynthesis pathway in response to citral.

    PubMed

    OuYang, Qiuli; Tao, Nengguo; Jing, Guoxing

    2016-08-11

    Green mold caused by Penicillium digitatum is the most damaging postharvest diseases of citrus fruit. Previously, we have observed that citral dose-dependently inhibited the mycelial growth of P. digitatum, with the minimum inhibitory concentration (MIC) of 1.78 mg/mL, but the underlying molecular mechanism is barely understood. In this study, the transcriptional profiling of the control and 1/2MIC-citral treated P. digitatum mycelia after 30 min of exposure were analyzed by RNA-Seq. A total of 6355 genes, including 2322 up-regulated and 4033 down-regulated genes, were found to be responsive to citral. These genes were mapped to 155 KEGG pathways, mainly concerning mRNA surveillance, RNA polymerase, RNA transport, aminoacyl-tRNA biosynthesis, ABC transporter, glycolysis/gluconeogenesis, citrate cycle, oxidative phosphorylation, sulfur metabolism, nitrogen metabolism, inositol phosphate metabolism, fatty acid biosynthesis, unsaturated fatty acids biosynthesis, fatty acid metabolism, and steroid biosynthesis. Particularly, citral exposure affected the expression levels of five ergosterol biosynthetic genes (e.g. ERG7, ERG11, ERG6, ERG3 and ERG5), which corresponds well with the GC-MS results, the reduction in ergosterol content, and accumulation of massive lanosterol. In addition, ERG11, the gene responsible for lanosterol 14α-demethylase, was observed to be the key down-regulated gene in response to citral. Our present finding suggests that citral could exhibit its antifungal activity against P. digitatum by the down-regulation of ergosterol biosynthesis.

  11. Classical Accreting Pulsars with NICER

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2014-01-01

    Soft excesses are very common center dot Lx > 1038 erg/s - reprocessing by optically thick material at the inner edge of the accretion disk center dot Lx < 1036 erg/s - photoionized or collisionally heated diffuse gas or thermal emission from the NS surface center dot Lx 1037 erg/s - either or both types of emission center dot NICER observations of soft excesses in bright X-ray pulsars combined with reflection modeling will constrain the ionization state, metalicity and dynamics of the inner edge of the magnetically truncated accretion disk Reflection models of an accretion disk for a hard power law - Strong soft excess below 3 keV from hot X-ray heated disk - For weakly ionized case: strong recombination lines - Are we seeing changes in the disk ionization in 4U1626-26? 13 years of weekly monitoring with RXTE PCA center dot Revealed an unexpectedly large population of Be/X-ray binaries compared to the Milky Way center dot Plotted luminosities are typical of "normal" outbursts (once per orbit) center dot The SMC provides an excellent opportunity to study a homogenous population of HMXBs with low interstellar absorption for accretion disk studies. Monitoring with NICER will enable studies of accretion disk physics in X-ray pulsars center dot The SMC provides a potential homogeneous low-absorption population for this study center dot NICER monitoring and TOO observations will also provide measurements of spinfrequencies, QPOs, pulsed fluxes, and energy spectra.

  12. Wide-field fundus autofluorescence abnormalities and visual function in patients with cone and cone-rod dystrophies.

    PubMed

    Oishi, Maho; Oishi, Akio; Ogino, Ken; Makiyama, Yukiko; Gotoh, Norimoto; Kurimoto, Masafumi; Yoshimura, Nagahisa

    2014-05-20

    To evaluate the clinical utility of wide-field fundus autofluorescence (FAF) in patients with cone dystrophy and cone-rod dystrophy. Sixteen patients with cone dystrophy (CD) and 41 patients with cone-rod dystrophy (CRD) were recruited at one institution. The right eye of each patient was included for analysis. We obtained wide-field FAF images using a ultra-widefield retinal imaging device and measured the area of abnormal FAF. The association between the area of abnormal FAF and the results of visual acuity measurements, kinetic perimetry, and electroretinography (ERG) were investigated. The mean age of the participants was 51.4 ± 17.4 years, and the mean logarithm of the minimum angle of resolution was 1.00 ± 0.57. The area of abnormal FAF correlated with the scotoma measured by the Goldman perimetry I/4e isopter (ρ = 0.79, P < 0.001). The area also correlated with amplitudes of the rod ERG (ρ = -0.63, P < 0.001), combined ERG a-wave (ρ = -0.72, P < 0.001), combined ERG b-wave (ρ = -0.66, P < 0.001), cone ERG (ρ = -0.44, P = 0.001), and flicker ERG (ρ = -0.47, P < 0.001). The extent of abnormal FAF reflects the severity of functional impairment in patients with cone-dominant retinal dystrophies. Fundus autofluorescence measurements are useful for predicting retinal function in these patients. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  13. Creation, characterization and utilization of Cryptococcus neoformans mutants sensitive to micafungin.

    PubMed

    Toh-E, Akio; Ohkusu, Misako; Shimizu, Kiminori; Yamaguchi, Masashi; Ishiwada, Naruhiko; Watanabe, Akira; Kamei, Katsuhiko

    2017-12-01

    We constructed deletion mutants of Cryptococcus neoformans var neoformans (serotype D) genes encoding late ergosterol biosynthetic pathway enzymes and found that the mutations enhanced susceptibility to various drugs including micafungin, one of the echinocandins, to which wild-type Cryptococcus strains show no susceptibility. Furthermore, through isolation of a mutant resistant to micafungin from a micafungin-sensitive erg mutant and genetic analysis of it, we found that the responsible mutation occurred in the hotspot 2 of FKS1 encoding β-1, 3-glucan synthase, indicating that micafungin inhibited the growth of the erg mutant via inhibiting Fks1 activity. Addition of ergosterol to the culture of the erg mutants recovered the resistance to micafungin, suggesting that the presence of ergosterol in membrane inhibits the accession of micafungin to its target. We found that a loss of one of genes encoding subunits of v-ATPase, VPH1, made Cryptococcus cells sensitive to micafungin. Our observation that the erg2 vph1 double mutant was more sensitive to micafungin than either single mutant suggests that these two genes act differently in becoming resistant to micafungin. The erg mutants allowed us to study the physiological significance of β-1, 3-glucan synthesis in C. neoformans; the inhibition of β-1, 3-glucan synthesis induced cell death and changes in cellular morphology. By observing the erg mutant cells recovering from the growth inhibition imposed by micafungin, we recognized β-1, 3-glucan synthesis would suppress filamentous growth in C. neoformans.

  14. X-ray and radio observations of flares from the RS Canum Venaticorum system UX ARIETIS

    NASA Astrophysics Data System (ADS)

    Tsuru, T.; Makishima, K.; Ohashi, T.; Inoue, H.; Koyama, K.; Turner, M. J. L.; Barstow, M. A.; McHardy, I. M.; Pye, J. P.; Tsunemi, H.; Kitamoto, S.; Taylor, A. R.; Nelson, R. F.

    In July 1987 the RS CVn system UX Ari was observed in the 2-20-keV X-ray band by Ginga, immediately followed by 5-GHz radio observations. UX Ari was found to be very active at both radio and X-ray frequencies. Quiescent X-ray emission with a luminosity of 3 x 10 to the 31st erg/s (in the 2-20-keV band) was detected, together with two intense X-ray flares up to 2 x 10 to the 32nd and 6 x 10 to the 31st erg/s, respectively. Both flare and quiescent X-ray spectra are well fitted by single-temperature thermal bremsstrahlung models, with the continuum temperature and emission measure in the range 4-7 kev (in kT) and (2-10) x 10 to the 54th/cu cm, respectively.

  15. Dark matter in the local group of galaxies

    NASA Astrophysics Data System (ADS)

    Morley, P. D.; Buettner, D. J.

    We describe the neutrino flavor (e = electron, μ = muon, τ = tau) masses as mi=e,μ,τ = m + Δmi with |Δmi| m < 1 and probably |Δmi| m ≪ 1. The quantity m is the degenerate neutrino mass. Because neutrino flavor is not a quantum number, this degenerate mass appears in the neutrino equation-of-state [P. D. Morley and D. J. Buettner, Int. J. Mod. Phys. D (2014), doi:10.1142/s0218271815500042.]. We apply a Monte Carlo computational physics technique to the Local Group (LG) of galaxies to determine an approximate location for a Dark Matter embedding Condensed Neutrino Object (CNO) [P. D. Morley and D. J. Buettner, Int. J. Mod. Phys. D (2016), doi:10.1142/s0218271816500899.]. The calculation is based on the rotational properties of the only spiral galaxies within the LG: M31, M33 and the Milky Way. CNOs could be the Dark Matter everyone is looking for and we estimate the CNO embedding the LG to have a mass 5.17 × 1015 M⊙ and a radius 1.316 Mpc, with the estimated value of m ≃ 0.8 eV/c2. The up-coming KATRIN experiment [https://www.katrin.kit.edu.] will either be the definitive result or eliminate condensed neutrinos as a Dark Matter candidate.

  16. Absolute neutrino mass measurements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wolf, Joachim

    2011-10-06

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments inmore » Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.« less

  17. Toluene Inhalation Exposure for 13 Weeks Causes Persistent Changes in Electroretinograms of Long-Evans Rats

    PubMed Central

    Boyes, William K.; Bercegeay, Mark; Degn, Laura; Beasley, Tracey E.; Evansky, Paul A.; Mwanza, Jean Claude; Geller, Andrew M.; Pinckney, Charles; Nork, T. Michael; Bushnell, Philip J.

    2016-01-01

    Studies of humans chronically exposed to volatile organic solvents have reported impaired visual functions, including low contrast sensitivity and reduced color discrimination. These reports, however, lacked confirmation from controlled laboratory experiments. To address this question experimentally, we examined visual function by recording visual evoked potentials (VEP) and/or electroretinograms (ERG) from four sets of rats exposed repeatedly to toluene. In addition, eyes of the rats were examined with an ophthalmoscope and some of the retinal tissues were evaluated for rod and M-cone photoreceptor immunohistochemistry. The first study examined rats following exposure to 0, 10, 100 or 1000 ppm toluene by inhalation (6 hr/d, 5 d/wk) for 13 weeks. One week after the termination of exposure, the rats were implanted with chronically indwelling electrodes and the following week pattern-elicited VEPs were recorded. VEP amplitudes were not significantly changed by toluene exposure. Four to five weeks after completion of exposure, rats were dark-adapted overnight, anesthetized, and several sets of electroretinograms (ERG) were recorded. In dark-adapted ERGs recorded over a 5-log (cd-s/m2) range of flash luminance, b-wave amplitudes were significantly reduced at high stimulus luminance values in rats previously exposed to 1000 ppm toluene. A second set of rats, exposed concurrently with the first set, was tested approximately one year after the termination of 13 weeks of exposure to toluene. Again, dark-adapted ERG b-wave amplitudes were reduced at high stimulus luminance values in rats previously exposed to 1000 ppm toluene. A third set of rats was exposed to the same concentrations of toluene for only 4 weeks, and a fourth set of rats exposed to 0 or 1000 ppm toluene for 4 weeks were tested approximately 1 year after the completion of exposure. No statistically significant reductions of ERG b-wave amplitude were observed in either set of rats exposed for 4 weeks. No

  18. X-ray spectroscopy of the super soft source RXJ0925.7-475

    NASA Technical Reports Server (NTRS)

    Ebisawa, Ken; Asai, Kazumi; Dotani, Tadayasu; Mukai, Koji; Smale, Alan

    1996-01-01

    The super soft source (SSS) RXJ 0925.7-475 was observed with the Advanced Satellite for Cosmology and Astrophysics (ASCA) solid state spectrometer and its energy spectrum was analyzed. A simple black body model does not fit the data, and several absorption edges of ionized heavy elements are required. Without the addition of absorption edges, the best-fit black body radius and the estimated bolometric luminosity are 6800 (d/1 kpc) km and 1.2 x 10(exp 37) (d/1 kps)(exp 2) erg/s, respectively. The introduction of absorption edges significantly reduces the best-fit radius and luminosity to 140 (d/1 KPS) km and 6 x 10(exp 34) (d/1 kpc)(exp 2) erg/s, respectively. This suggests that the estimation of the emission region size and luminosity of SSS based on the black body model fit to the observed data is not reliable.

  19. How fast can an AGN shut down? XMM-Newton observation of IC 2497

    NASA Astrophysics Data System (ADS)

    Schawinski, Kevin

    2008-10-01

    We propose to observe IC 2497 with XMM-Newton to detect, or rule out, an obscured AGN that might account for the illumination of `Hanny's Voorwerp'. The Voorwerp is a highly ionised cloud of gas extended over 15-25 kpc next to the spiral galaxy IC 2497. There is no source of ionisation within the Voorwerp, implicating a luminous 1E44 erg/s AGN in IC 2497 as the source. Swift XRT observations do not yield a detection, allowing the presence of a highly obscured, sufficiently luminous AGN. With 34 ksec of XMM observations, we could detect an obscured AGN down to 1E42 erg/s. We can thus either locate an obscured AGN, or we can for the first time constrain the shutdown time scale for a powerful AGN, as it drops by a factor of 100 in luminosity in 1E5 years.

  20. Pattern reversal responses in man and cat: a comparison.

    PubMed

    Schuurmans, R P; Berninger, T

    1984-01-01

    In 42 enucleated and arterially perfused cat eyes, graded potentials were recorded from the retina (ERG) and from the optic nerve ( ONR ) in response to checker-board stimuli, reversing at a low temporal frequency in a square wave mode. The ERG and ONR responses show an almost perfect duplication of the response to each reversal of the pattern and exhibit, in contrast to luminance responses, striking similarities in response characteristics such as amplitude, wave shape and time course. Furthermore, the amplitude versus check size plots coincide in both responses. In cat, pattern reversal responses can be recorded from 74 to 9 min of arc, correlating to the cat's visual resolution. In man, almost identical responses can be recorded for the pattern ERG. However, in accordance with the difference in visual resolution in man and cat, a parallel shift for the human pattern reversal ERG response to higher spatial frequencies is observed.

  1. Rabbit electroretinograms evoked by 632.8nm laser flash stimuli

    NASA Astrophysics Data System (ADS)

    Yang, Zai-Fu; Chen, Hong-Xia; Wang, Jia-Rui; Guan, Bo-Lin; Yu, Guang-Yuan; Zhang, Xiao-Na; Zhang, Wen-Yuan; Yang, Jing-Geng

    2012-12-01

    The flash electroretinography is a standard electrophysiological method and widely employed in basic research and ophthalmology clinics, of which the stimulus is usually white flash from dome stimulator. However, little is known about the electroretinograms (ERGs) evoked by monochromatic laser flash stimuli. The goal of this research effort is to quantify the ERGs of dark-adapted New Zealand rabbits elicited by He-Ne laser flash with wavelength 632.8 nm. The flash field was a Maxwellian viewing disc with angular subtense of 8.5°, 13.3° or 20.2°. The stimulus duration was 12 ms, 22 ms, 70 ms or 220 ms. The laser flash power incident on the cornea varied from 2.2 nW through 22 mW. Under the condition of 20 ms stimulus duration and 20.2° flash field, the ERG of New Zealand rabbit was compared with that of Chinchilla gray rabbit. Results showed that for the ERG b-wave, with the increase of laser energy, the amplitude first increased, then met a trough and finally increased again, the implicit time decreased first and then met a platform. While for the ERG a-wave, the amplitude increased and the implicit time decreased monotonically. Longer stimulus duration led to lower b-wave amplitude under equal flash power level. The flash field size showed limited effect on the ERG, especially on the low energy end. As compared with the pigmented rabbit, the albino rabbit was more sensitive and the threshold energy for b-wave excitation was about 10 times lower.

  2. Strategies to reduce the risk of drug-induced QT interval prolongation: a pharmaceutical company perspective.

    PubMed

    Pollard, C E; Valentin, J-P; Hammond, T G

    2008-08-01

    Drug-induced prolongation of the QT interval is having a significant impact on the ability of the pharmaceutical industry to develop new drugs. The development implications for a compound causing a significant effect in the 'Thorough QT/QTc Study' -- as defined in the clinical regulatory guidance (ICH E14) -- are substantial. In view of this, and the fact that QT interval prolongation is linked to direct inhibition of the hERG channel, in the early stages of drug discovery the focus is on testing for and screening out hERG activity. This has led to understanding of how to produce low potency hERG blockers whilst retaining desirable properties. Despite this, a number of factors mean that when an integrated risk assessment is generated towards the end of the discovery phase (by conducting at least an in vivo QT assessment) a QT interval prolongation risk is still often apparent; inhibition of hERG channel trafficking and partitioning into cardiac tissue are just two confounding factors. However, emerging information suggests that hERG safety margins have high predictive value and that when hERG and in vivo non-clinical data are combined, their predictive value to man, whilst not perfect, is >80%. Although understanding the anomalies is important and is being addressed, of greater importance is developing a better understanding of TdP, with the aim of being able to predict TdP rather than using an imperfect surrogate marker (QT interval prolongation). Without an understanding of how to predict TdP risk, high-benefit drugs for serious indications may never be marketed.

  3. Phenotypes in defined genotypes including siblings with Usher syndrome.

    PubMed

    Malm, Eva; Ponjavic, Vesna; Möller, Claes; Kimberling, William J; Andréasson, Sten

    2011-06-01

    To characterize visual function in defined genotypes including siblings with Usher syndrome. Thirteen patients with phenotypically different subtypes of Usher syndrome, including 3 families with affected siblings, were selected. Genetic analysis and ophthalmological examinations including visual fields, full-field electroretinography (ERG), multifocal electroretinography (mf ERG), and optical coherence tomography (OCT) were assessed. The patients' degree of visual handicap was evaluated by a questionnaire (ADL). Twelve of thirteen patients were genotyped as Usher 1B, 1D, 1F, 2A, 2C or 3A. In 12 of 13 patients examined with ERG the 30 Hz flickering light response revealed remaining cone function. In 3 of the patients with Usher type 1 mf ERG demonstrated a specific pattern, with a sharp distinction between the area with reduced function and the central area with remaining macular function and normal peak time. OCT demonstrated loss of foveal depression with distortion of the foveal architecture in the macula in all patients. The foveal thickness ranged from 159 to 384 µm and was not correlated to retinal function. Three siblings shared the same mutation for Usher 2C but in contrast to previous reports regarding this genotype, 1 of them diverged in phenotype with substantially normal visual fields, almost normal OCT and mf ERG findings, and only moderately reduced rod and cone function according to ERG. Evaluation of visual function comprising both the severity of the rod cone degeneration and the function in the macular region confirm phenotypical heterogeneity within siblings and between different genotypes of Usher syndrome.

  4. Retinal toxicity related to hydroxychloroquine in patients with systemic lupus erythematosus and rheumatoid arthritis.

    PubMed

    Telek, Hande Husniye; Yesilirmak, Nilufer; Sungur, Gulten; Ozdemir, Yaprak; Yesil, Nesibe Karahan; Ornek, Firdevs

    2017-12-01

    To compare the retinal toxicity due to hydroxychloroquine (HCQ) use in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) using multifocal electroretinography (mfERG), fundus autofluorescence (FAF) and optical coherence tomography (OCT). Patients who were using HCQ due to SLE and RA, and healthy subjects evaluated in this study. Central foveal thickness (CFT), inner-outer segment (IS-OS) junction irregularity, retinal nerve fiber layer thickness, mfERG and FAF measurements were performed to evaluate retinal toxicity. Study included 35 eyes of 35 SLE patients, 40 eyes of 40 RA patients and 20 eyes of 20 healthy subjects. In SLE group, retinal abnormality was found in three eyes with mfERG, in one eye with FAF and in four eyes with OCT. In RA group, retinal abnormality was found in 10 eyes with mfERG, in five eyes with FAF and in nine eyes with OCT. A statistically significant difference was found with respect to mfERG between "eyes with abnormal responses and without abnormal responses" and "eyes with abnormal responses and controls" (p < 0.05). A statistically significant difference was found with respect to CFT between "eyes with IS-OS junction irregularities and without IS-OS junction irregularities" and "eyes with/without IS-OS junction irregularities and controls" (p < 0.05). The use of HCQ seems to cause retinal toxicity more often in RA patients compared to SLE patients. For the early detection of retinal changes, OCT and mfERG can be used as screening tools due to their higher sensitivity rates compared to other tests.

  5. Expected utility versus expected regret theory versions of decision curve analysis do generate different results when treatment effects are taken into account.

    PubMed

    Hozo, Iztok; Tsalatsanis, Athanasios; Djulbegovic, Benjamin

    2018-02-01

    Decision curve analysis (DCA) is a widely used method for evaluating diagnostic tests and predictive models. It was developed based on expected utility theory (EUT) and has been reformulated using expected regret theory (ERG). Under certain circumstances, these 2 formulations yield different results. Here we describe these situations and explain the variation. We compare the derivations of the EUT- and ERG-based formulations of DCA for a typical medical decision problem: "treat none," "treat all," or "use model" to guide treatment. We illustrate the differences between the 2 formulations when applied to the following clinical question: at which probability of death we should refer a terminally ill patient to hospice? Both DCA formulations yielded identical but mirrored results when treatment effects are ignored; they generated significantly different results otherwise. Treatment effect has a significant effect on the results derived by EUT DCA and less so on ERG DCA. The elicitation of specific values for disutilities affected the results even more significantly in the context of EUT DCA, whereas no such elicitation was required within the ERG framework. EUT and ERG DCA generate different results when treatment effects are taken into account. The magnitude of the difference depends on the effect of treatment and the disutilities associated with disease and treatment effects. This is important to realize as the current practice guidelines are uniformly based on EUT; the same recommendations can significantly differ if they are derived based on ERG framework. © 2016 The Authors. Journal of Evaluation in Clinical Practice Published by John Wiley & Sons Ltd.

  6. Molecular Mechanism of Terbinafine Resistance in Saccharomyces cerevisiae

    PubMed Central

    Leber, Regina; Fuchsbichler, Sandra; Klobučníková, Vlasta; Schweighofer, Natascha; Pitters, Eva; Wohlfarter, Kathrin; Lederer, Mojca; Landl, Karina; Ruckenstuhl, Christoph; Hapala, Ivan; Turnowsky, Friederike

    2003-01-01

    Ten mutants of the yeast Saccharomyces cerevisiae resistant to the antimycotic terbinafine were isolated after chemical or UV mutagenesis. Molecular analysis of these mutants revealed single base pair exchanges in the ERG1 gene coding for squalene epoxidase, the target of terbinafine. The mutants did not show cross-resistance to any of the substrates of various pleiotropic drug resistance efflux pumps tested. The ERG1 mRNA levels in the mutants did not differ from those in the wild-type parent strains. Terbinafine resistance was transmitted with the mutated alleles in gene replacement experiments, proving that single amino acid substitutions in the Erg1 protein were sufficient to confer the resistance phenotype. The amino acid changes caused by the point mutations were clustered in two regions of the Erg1 protein. Seven mutants carried the amino acid substitutions F402L (one mutant), F420L (one mutant), and P430S (five mutants) in the C-terminal part of the protein; and three mutants carried an L251F exchange in the central part of the protein. Interestingly, all exchanges identified involved amino acids which are conserved in the squalene epoxidases of yeasts and mammals. Two mutations that were generated by PCR mutagenesis of the ERG1 gene and that conferred terbinafine resistance mapped in the same regions of the Erg1 protein, with one resulting in an L251F exchange and the other resulting in an F433S exchange. The results strongly indicate that these regions are responsible for the interaction of yeast squalene epoxidase with terbinafine. PMID:14638499

  7. Disease course of patients with unilateral pigmentary retinopathy.

    PubMed

    Potsidis, Emorfily; Berson, Eliot L; Sandberg, Michael A

    2011-11-29

    To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Mean annual rates of change for the affected eyes were -4.9% for visual field area, -4.7% for ERG amplitude to 0.5-Hz flashes, and -4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥ 40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity.

  8. ERF is a Potential ERK-Modulated Tumor Suppressor in Prostate Cancer

    DTIC Science & Technology

    2017-10-01

    15 20 P = 0 .0 17 P < 0 .0 00 1 CRISPR –Cas9 sgERF CRISPR –Cas9 sgNT –dox (TetOn_Flag–ERF) +dox (TetOn_Flag–ERF) shNT, sgNT shERF_2, sgNT shERF_2...Pten−/−;R26ERG/ERG organoids infected with CRISPR –Cas9 targeting ERF (sgERF). Data are median ± interquartile range; n = 10 tumours per condition, P...cancer21. We next asked whether ERF could modulate oncogenicity mediated by ERG expression. First, we used CRISPR –Cas9 (clustered regularly interspaced

  9. Endogenous Reference Genes and Their Quantitative Real-Time PCR Assays for Genetically Modified Bread Wheat (Triticum aestivum L.) Detection.

    PubMed

    Yang, Litao; Quan, Sheng; Zhang, Dabing

    2017-01-01

    Endogenous reference genes (ERG) and their derivate analytical methods are standard requirements for analysis of genetically modified organisms (GMOs). Development and validation of suitable ERGs is the primary step for establishing assays that monitoring the genetically modified (GM) contents in food/feed samples. Herein, we give a review of the ERGs currently used for GM wheat analysis, such as ACC1, PKABA1, ALMT1, and Waxy-D1, as well as their performances in GM wheat analysis. Also, we discussed one model for developing and validating one ideal RG for one plant species based on our previous research work.

  10. Maculopathy following exposure to visible and infrared radiation from a laser pointer: a clinical case study.

    PubMed

    Hanson, James V M; Sromicki, Julian; Mangold, Mario; Golling, Matthias; Gerth-Kahlert, Christina

    2016-04-01

    Laser pointer devices have become increasingly available in recent years, and their misuse has caused a number of ocular injuries. Online distribution channels permit trade in devices which may not conform to international standards in terms of their output power and spectral content. We present a case study of ocular injury caused by one such device. The patient was examined approximately 9 months following laser exposure using full-field and multifocal electroretinography (ERG and MF-ERG), electrooculography (EOG), and optical coherence tomography (OCT), in addition to a full ophthalmological examination. MF-ERG, OCT, and the ophthalmological examination were repeated 7 months after the first examination. The output of the laser pointer was measured. Despite severe focal damage to the central retina visible fundoscopically and with OCT, all electrophysiological examinations were quantitatively normal; however, qualitatively the central responses of the MF-ERG appeared slightly reduced. When the MF-ERG was repeated 7 months later, all findings were normal. The laser pointer was found to emit both visible and infrared radiation in dangerous amounts. Loss of retinal function following laser pointer injury may not always be detectable using standard electrophysiological tests. Exposure to non-visible radiation should be considered as a possible aggravating factor when assessing cases of alleged laser pointer injury.

  11. The determination of dark adaptation time using electroretinography in conscious miniature Schnauzer dogs.

    PubMed

    Yu, Hyung-Ah; Jeong, Man-Bok; Park, Shin-Ae; Kim, Won-Tae; Kim, Se-Eun; Chae, Je-Min; Yi, Na-Young; Seo, Kang-Moon

    2007-12-01

    The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd.s/m(2) was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p < 0.05). Thereafter, no significant differences in amplitude occurred over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 +/- 18.47 microV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p < 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 +/- 17.79 microV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs.

  12. Surveys with Athena: results from detailed SIXTE simulations

    NASA Astrophysics Data System (ADS)

    Lanzuisi, G.; Comastri, A.; Aird, J.; Brusa, M.; Cappelluti, N.; Gilli, R.; Matute, I.

    2017-10-01

    "Formation and early growth of BH' and "Accretion by supermassive BH through cosmic time' are two of the scientific objectives of the Athena mission. To these and other topics (i.e. first galaxy groups, cold and warm obscuration and feedback signatures in AGN at high z), a large fraction (20-25%) of the Athena Mock Observing Plan is devoted, in the form of a multi-tiered (deep-medium-wide) survey with the WFI. We used the flexible SIXTE simulator to study the impact of different instrumental configurations, in terms of WFI FOV, mirror psf, background levels, on the performance in the three layers of the WFI survey. We mainly focus on the scientific objective that drives the survey configuration: the detection of at least 10 AGN at z=6-8 with Log(LX)=43-43.5 erg/s and 10 at z=8.10 with Log(LX)=44-44.5 erg/s. Implications for other scientific objectives involved in the survey are also discussed.

  13. Cone dysfunctions in retinitis pigmentosa with retinal nerve fiber layer thickening.

    PubMed

    Sobacı, Güngör; Ozge, Gökhan; Gündoğan, Fatih Ç

    2012-01-01

    To investigate whether or not thicker retinal nerve fiber layer (RNFL) in retinitis pigmentosa (RP) patients relates to functional abnormalities of the photoreceptors. Optical coherence tomography-based RNFL thickness was measured by Stratus-3™ (Zeiss, Basel, Switzerland) optical coherence tomography and electroretinogram (ERG) recordings made using the RETI-port(®) system (Roland, Wiesbaden, Germany) in 27 patients with retinitis pigmentosa and in 30 healthy subjects. Photopic ERG b-wave amplitude, cone ERG b-wave latency, 30 Hz flicker amplitude, and 30 Hz flicker latency had significant correlations to the RNFL-temporal (r = -0.55, P = 0.004, r = 0.68, P = 0.001, r = -0.65, P = 0.001, and r = -0.52, P = 0.007, respectively). Eyes with thicker RNFL (ten eyes) differed significantly from those with thinner RNFL (eight eyes) regarding cone ERG b-wave latency values only (P = 0.001). Thicker RNFL in patients with retinitis pigmentosa may be associated with functional abnormality of the cone system.

  14. Energies of GRB blast waves and prompt efficiencies as implied by modelling of X-ray and GeV afterglows

    NASA Astrophysics Data System (ADS)

    Beniamini, Paz; Nava, Lara; Duran, Rodolfo Barniol; Piran, Tsvi

    2015-11-01

    We consider a sample of 10 gamma-ray bursts with long-lasting ( ≳ 102 s) emission detected by Fermi/Large Area Telescope and for which X-ray data around 1 d are also available. We assume that both the X-rays and the GeV emission are produced by electrons accelerated at the external forward shock, and show that the X-ray and the GeV fluxes lead to very different estimates of the initial kinetic energy of the blast wave. The energy estimated from GeV is on average ˜50 times larger than the one estimated from X-rays. We model the data (accounting also for optical detections around 1 d, if available) to unveil the reason for this discrepancy and find that good modelling within the forward shock model is always possible and leads to two possibilities: (i) either the X-ray emitting electrons (unlike the GeV emitting electrons) are in the slow-cooling regime or (ii) the X-ray synchrotron flux is strongly suppressed by Compton cooling, whereas, due to the Klein-Nishina suppression, this effect is much smaller at GeV energies. In both cases the X-ray flux is no longer a robust proxy for the blast wave kinetic energy. On average, both cases require weak magnetic fields (10-6 ≲ ɛB ≲ 10-3) and relatively large isotropic kinetic blast wave energies 10^{53} erg<{E}_{0,kin}<10^{55} erg corresponding to large lower limits on the collimated energies, in the range 10^{52} erg<{E}_{θ ,kin}<5× 10^{52} erg for an ISM (interstellar medium) environment with n ˜ 1 cm-3 and 10^{52} erg<{E}_{θ ,kin}<10^{53} erg for a wind environment with A* ˜ 1. These energies are larger than those estimated from the X-ray flux alone, and imply smaller inferred values of the prompt efficiency mechanism, reducing the efficiency requirements on the still uncertain mechanism responsible for prompt emission.

  15. Simultaneous X-Ray, Gamma-Ray, and Radio Observations of the Repeating Fast Radio Burst FRB 121102

    NASA Astrophysics Data System (ADS)

    Scholz, P.; Bogdanov, S.; Hessels, J. W. T.; Lynch, R. S.; Spitler, L. G.; Bassa, C. G.; Bower, G. C.; Burke-Spolaor, S.; Butler, B. J.; Chatterjee, S.; Cordes, J. M.; Gourdji, K.; Kaspi, V. M.; Law, C. J.; Marcote, B.; McLaughlin, M. A.; Michilli, D.; Paragi, Z.; Ransom, S. M.; Seymour, A.; Tendulkar, S. P.; Wharton, R. S.

    2017-09-01

    We undertook coordinated campaigns with the Green Bank, Effelsberg, and Arecibo radio telescopes during Chandra X-ray Observatory and XMM-Newton observations of the repeating fast radio burst FRB 121102 to search for simultaneous radio and X-ray bursts. We find 12 radio bursts from FRB 121102 during 70 ks total of X-ray observations. We detect no X-ray photons at the times of radio bursts from FRB 121102 and further detect no X-ray bursts above the measured background at any time. We place a 5σ upper limit of 3 × 10‑11 erg cm‑2 on the 0.5–10 keV fluence for X-ray bursts at the time of radio bursts for durations < 700 ms, which corresponds to a burst energy of 4 × 1045 erg at the measured distance of FRB 121102. We also place limits on the 0.5–10 keV fluence of 5 × 10‑10 and 1 × 10‑9 erg cm‑2 for bursts emitted at any time during the XMM-Newton and Chandra observations, respectively, assuming a typical X-ray burst duration of 5 ms. We analyze data from the Fermi Gamma-ray Space Telescope Gamma-ray Burst Monitor and place a 5σ upper limit on the 10–100 keV fluence of 4 × 10‑9 erg cm‑2 (5 × 1047 erg at the distance of FRB 121102) for gamma-ray bursts at the time of radio bursts. We also present a deep search for a persistent X-ray source using all of the X-ray observations taken to date and place a 5σ upper limit on the 0.5–10 keV flux of 4 × 10‑15 erg s‑1 cm‑2 (3 × 1041 erg s‑1 at the distance of FRB 121102). We discuss these non-detections in the context of the host environment of FRB 121102 and of possible sources of fast radio bursts in general.

  16. Molecular evidence that invasive adenocarcinoma can mimic prostatic intraepithelial neoplasia (PIN) and intraductal carcinoma through retrograde glandular colonization.

    PubMed

    Haffner, Michael C; Weier, Christopher; Xu, Meng Meng; Vaghasia, Ajay; Gürel, Bora; Gümüşkaya, Berrak; Esopi, David M; Fedor, Helen; Tan, Hsueh-Li; Kulac, Ibrahim; Hicks, Jessica; Isaacs, William B; Lotan, Tamara L; Nelson, William G; Yegnasubramanian, Srinivasan; De Marzo, Angelo M

    2016-01-01

    Prostate cancer often manifests as morphologically distinct tumour foci and is frequently found adjacent to presumed precursor lesions such as high-grade prostatic intraepithelial neoplasia (HGPIN). While there is some evidence to suggest that these lesions can be related and exist on a pathological and morphological continuum, the precise clonal and temporal relationships between precursor lesions and invasive cancers within individual tumours remain undefined. Here, we used molecular genetic, cytogenetic, and histological analyses to delineate clonal, temporal, and spatial relationships between HGPIN and cancer lesions with distinct morphological and molecular features. First, while confirming the previous finding that a substantial fraction of HGPIN lesions associated with ERG-positive cancers share rearrangements and overexpression of ERG, we found that a significant subset of such HGPIN glands exhibit only partial positivity for ERG. This suggests that such ERG-positive HGPIN cells either rapidly invade to form adenocarcinoma or represent cancer cells that have partially invaded the ductal and acinar space in a retrograde manner. To clarify these possibilities, we used ERG expression status and TMPRSS2-ERG genomic breakpoints as markers of clonality, and PTEN deletion status to track temporal evolution of clonally related lesions. We confirmed that morphologically distinct HGPIN and nearby invasive cancer lesions are clonally related. Further, we found that a significant fraction of ERG-positive, PTEN-negative HGPIN and intraductal carcinoma (IDC-P) lesions are most likely clonally derived from adjacent PTEN-negative adenocarcinomas, indicating that such PTEN-negative HGPIN and IDC-P lesions arise from, rather than give rise to, the nearby invasive adenocarcinoma. These data suggest that invasive adenocarcinoma can morphologically mimic HGPIN through retrograde colonization of benign glands with cancer cells. Similar clonal relationships were also seen for

  17. [The extraction and analysis of a- and b- wave from electroretinogram in human].

    PubMed

    Chen, Zi-he; Zheng, Chang-wei; Lei, Bo

    2013-12-01

    To determine the frequency range of a-b wave complex in the dark- and light-adapted electroretinogram (ERG) and to isolate the pure a- and b- waves. Case series study. Full-field ERGs were recorded in 16 eyes of 8 normal volunteers from October to November 2011. Digital filtering technique was used to extract the a- and b-waves from dark- and light-adapted ERG responses. The timings of a- and b-wave were measured to determine the frequency range of a-b wave complex. Major frequency components were determined from power spectra using fast Fourier transform (FFT). The effect of different order settings in the digital filter were compared to investigate the optimum condition, where the oscillatory potential (OP) was completely removed while the amplitudes and phases of the a- and b- waves were less affected. The Student-t test was used to compare the frequency range of a-b wave complex in dark- and light-adapted ERG. The averaged frequency range of the dark-adapted a-b wave complex was from (14.99 ± 2.39) to (25.35 ± 3.77) Hz, compared with (25.22 ± 6.56) to (32.47 ± 3.68) Hz for the light-adapted a-b wave complex, respectively, indicating the frequency range of the dark-adapted a-b wave complex was significantly less than the light-adapted a-b wave complex (t = 7.910, 7.693; both P < 0.01). The third order of the digital filter and a passband of 1 to 45 Hz was the best choice in term of removing the high frequency OP from the waveform of ERG and keeping the amplitude and phase of the a- and b- waves. The frequency of a-b wave complex is lower than that of OP. Therefore the a- and b- waves can be isolated from OP using different digital filter settings in human ERG. A third order and a passband of 1 to 45 Hz is the best choice to extract pure a- and b- waves from the original ERG.

  18. The NuSTAR Serendipitous Survey: The 40-month Catalog and the Properties of the Distant High-Energy X-Ray Source Population

    NASA Technical Reports Server (NTRS)

    Lansbury, G. B.; Stern, D.; Aird, J.; Alexander, D. M.; Fuentes, C.; Harrison, F. A.; Treister, E.; Bauer, F. E.; Tomsick, J. A.; Balokovic, M.; hide

    2017-01-01

    We present the first full catalog and science results for the Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey. The catalog incorporates data taken during the first 40 months of NuSTAR operation, which provide approx. 20 Ms of effective exposure time over 331 fields, with an areal coverage of 13 deg2, and 497 sources detected in total over the 324 keV energy range. There are 276 sources with spectroscopic redshifts and classifications, largely resulting from our extensive campaign of ground-based spectroscopic follow-up. We characterize the overall sample in terms of the X-ray, optical, and infrared source properties. The sample is primarily composed of active galactic nuclei (AGNs), detected over a large range in redshift from z = 0.002 to 3.4 (median of [z] = 0.56), but also includes 16 spectroscopically confirmed Galactic sources. There is a large range in X-ray flux, from log(f_3-24 keV/erg/s/sq cm) approx. -14 to -11, and in rest-frame 10-40 keV luminosity, from log(L10-40 keV/erg/s) approx. 39 to 46, with a median of 44.1. Approximately 79% of the NuSTAR sources have lower-energy (<10 keV) X-ray counterparts from XMM-Newton, Chandra, and Swift XRT. The mid-infrared (MIR) analysis, using WISE all-sky survey data, shows that MIR AGN color selections miss a large fraction of the NuSTAR-selected AGN population, from approx. 15% at the highest luminosities (LX> 10(exp 44) erg/s) to 80 at the lowest luminosities (LX > 10(exp 43) erg/s).

  19. Nickel-foam-supported ruthenium oxide/graphene sandwich composite constructed via one-step electrodeposition route for high-performance aqueous supercapacitors

    NASA Astrophysics Data System (ADS)

    Li, Meng; He, Hanwei

    2018-05-01

    A high-performance supercapacitor both considered high power and high energy density is needed for its applications such as portable electronics and electric vehicles. Herein, we construct a high-performance ruthenium oxide/graphene (RuO2-ERG) composite directly grown on Ni foam through cyclic voltammetric deposition process. The RuO2-ERG composite with sandwich structure is achieved effectively from a mixed solution of graphene oxide and ruthenium trichloride in the -1.4 V to 1.0 V potential range at a scan rate of 5 mV s-1. The electrochemical performance is optimized by tuning the concentration of the ruthenium trichloride. This integrative RuO2-ERG composite electrode can effectively maintains the accessible surface for redox reaction and stable channels for electrolyte penetration, leading to an improved electrochemical performance. Symmetrical aqueous supercapacitors based on RuO2-ERG electrodes exhibit a wider operational voltage window of 1.5 V. The optimized RuO2-ERG electrode displays a superior specific capacitance with 89% capacitance retention upon increasing the current density by 50 times. A high energy density of 43.8 W h kg-1 at a power density of 0.75 kW kg-1 is also obtained, and as high as 39.1 W h kg-1 can be retained at a power density of 37.5 kW kg-1. In addition, the capacitance retention is still maintained at 92.8% even after 10,000 cycles. The excellent electrochemical performance, long-term cycle stability, and the ease of preparation demonstrate that this typical RuO2-ERG electrode has great potentialities to develop high-performance supercapacitors.

  20. The effects of retinal abnormalities on the multifocal visual evoked potential.

    PubMed

    Chen, John Y; Hood, Donald C; Odel, Jeffrey G; Behrens, Myles M

    2006-10-01

    To examine the effects on the amplitude and latency of the multifocal visual evoked potential (mfVEP) in retinal diseases associated with depressed multifocal electroretinograms (mfERG). Static automated perimetry (SAP), mfERGs, and mfVEPs were obtained from 15 individuals seen by neuro-ophthalmologists and diagnosed with retinal disease based on funduscopic examination, visual field, and mfERG. Optic neuropathy was ruled out in all cases. Diagnoses included autoimmune retinopathy (n = 3), branch retinal arterial occlusion (n = 3), branch retinal vein occlusion (n = 1), vitamin A deficiency (n = 1), digoxin/age-related macular degeneration (n = 1), multiple evanescent white dot syndrome (n = 1), and nonspecific retinal disease (n = 5). Patients were selected from a larger group based on abnormal mfERG amplitudes covering a diameter of 20 degrees or greater. Fourteen (93%) of 15 patients showed significant mfVEP delays, as determined by either mean latency or the probability of a cluster of delayed local responses. Thirteen of 15 patients had normal mfVEP amplitudes in regions corresponding to markedly reduced or nonrecordable mfERG responses. These findings can be mimicked in normal individuals by viewing the display through a neutral-density filter. Retinal diseases can result in mfVEPs of relatively normal amplitudes, often with delays, in regions showing decreased mfERG responses and visual field sensitivity loss. Consequently, a retinal problem can be missed, or dismissed as functional, if a diagnosis is based on an mfVEP of normal or near-normal amplitude. Further, in patients with marked mfVEP delays, a retinal problem could be confused with optic neuritis, especially in a patient with a normal appearing fundus.

  1. Disease Course of Patients with Unilateral Pigmentary Retinopathy

    PubMed Central

    Potsidis, Emorfily; Berson, Eliot L.

    2011-01-01

    Purpose. To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Methods. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Results. Mean annual rates of change for the affected eyes were −4.9% for visual field area, −4.7% for ERG amplitude to 0.5-Hz flashes, and −4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). Conclusions. The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity. PMID:21989720

  2. Witnessing the first sign of retinitis pigmentosa onset in the allegedly normal eye of a case of unilateral RP: a 30-year follow-up.

    PubMed

    Gauvin, Mathieu; Chakor, Hadi; Koenekoop, Robert K; Little, John M; Lina, Jean-Marc; Lachapelle, Pierre

    2016-06-01

    A patient initially presented with constricted visual field, attenuated retinal vasculature, pigmentary clumping and reduced ERG in OS only, suggestive of unilateral retinitis pigmentosa (RP). This patient was subsequently seen on eight occasions (over three decades), and, with time, the initially normal eye (OD) gradually showed signs of RP-like degeneration. The purpose of this study was to evaluate which clinical modality (visual field, funduscopy or electroretinography) could have first predicted this fate. At each time points, data obtained from our patient were compared to normative data using Z tests. At initial visit, all tests were significantly (p < 0.05) altered in OS and normal in OD. Visual field and retinal vessel diameter in OD reduced gradually to reach statistical significance at the 5th visit and 6th visit (21 and 22 years after the first examination, respectively). In OD, the amplitude of the scotopic and photopic ERGs reduced gradually and was significantly smaller than normal at the 2nd visit (after 11 years) and 3rd visit (after 18 years), respectively. When the photopic ERG was analyzed using the discrete wavelet transform (DWT), we were able to detect a significant change at the 2nd visit (after 11 years) instead of the 3rd visit (18 years). Our study allowed us to witness the earliest manifestation of an RP disease process. The ERG was the first test to detect significant RP changes. A significantly earlier detection of ERG anomalies was obtained when the DWT was used, demonstrating its advantage for early detection of ERG changes.

  3. Electroretinographic modifications induced by agomelatine: a novel avenue to the understanding of the claimed antidepressant effect of the drug?

    PubMed Central

    Fornaro, Michele; Bandini, Fabio; Cestari, Luca; Cordano, Christian; Ogliastro, Carla; Albano, Claudio; De Berardis, Domenico; Martino, Matteo; Escelsior, Andrea; Rocchi, Giulio; Fornaro, Pantaleo; De Pasquale, Concetta

    2014-01-01

    Background Agomelatine, the first melatonergic antidepressant, has been postulated to enhance the dopaminergic activity at the central nervous system by 5-hydroxytryptamine receptor type 2C (5-HT2C) antagonism, yet the impact of melatonergic agonism on this pathway is unclear. Previous studies employing simplified, yet reliable, proxy (retinal) measures of the central nervous system dopaminergic activity, namely the standard electroretinogram (ERG) technique, suggested a reduction of the dopaminergic activity of the main ERG parameter, the b-wave, by pure melatonin, notably a hormone devoid of any antidepressant activity. Therefore, the antidepressant effects of the melatonergic antidepressant drug agomelatine should be reflected by a differential b-wave trend at ERG versus the effect exerted by pure melatonin, which was eventually found to be due to a contrasting effect on central dopaminergic transmission between the two drugs. Objective and methods The aim of the present preliminary ERG study carried out on healthy volunteers (n=23) receiving agomelatine was to explore the impact of this antidepressant drug on b-wave amplitude and latency of cones in daylight conditions using standard ERG. Results As postulated, agomelatine induced an enhancement of retinal dopaminergic activity, in contrast to what has been previously documented for melatonin. Conclusion Given the limits of this explorative study, especially the lack of a control group and that of a luminance response function to measure retinal sensitivity, further studies in clinical samples are recommended to allow more tenable conclusions about the potential role of ERG in discriminating between 5-HT antagonism and melatonergic (MT) agonism in relationship to the claimed antidepressant effect of agomelatine. PMID:24899809

  4. Rotational modulation and flares on RS Canum Venaticorum and BY Draconis-type stars. XV - Observations of Proxima Centauri and solar calibration data

    NASA Technical Reports Server (NTRS)

    Haisch, B. M.; Butler, C. J.; Foing, B.; Rodono, M.; Giampapa, M. S.

    1990-01-01

    Results are reported from simultaneous Exosat and IUE observations of flaring in Proxima Cen on March 2, 1985. The data are presented in extensive tables and sample spectra and discussed in detail. The peak emission of the soft-X-ray flare is found to be about 3 x 10 to the 27th erg/sec, with energy about 3 x 10 to the 30th erg and an associated increase in Mg II flux to 17,000-67,000 erg/sq cm sec, or about an order of magnitude lower than the solar value. The presence of flare- and microflare-related processes heating the corona is inferred.

  5. Effective molecular targeting of CDK4/6 and IGF-1R in a rare FUS-ERG fusion CDKN2A-deletion doxorubicin-resistant Ewing's sarcoma patient-derived orthotopic xenograft (PDOX) nude-mouse model

    PubMed Central

    Murakami, Takashi; Singh, Arun S.; Kiyuna, Tasuku; Dry, Sarah M.; Li, Yunfeng; James, Aaron W.; Igarashi, Kentaro; Kawaguchi, Kei; DeLong, Jonathan C.; Zhang, Yong; Hiroshima, Yukihiko; Russell, Tara; Eckardt, Mark A.; Yanagawa, Jane; Federman, Noah; Matsuyama, Ryusei; Chishima, Takashi; Tanaka, Kuniya; Bouvet, Michael; Endo, Itaru; Eilber, Fritz C.; Hoffman, Robert M.

    2016-01-01

    Ewing's sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewing's sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewing's sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm3: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewing's sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer. PMID:27286459

  6. Effective molecular targeting of CDK4/6 and IGF-1R in a rare FUS-ERG fusion CDKN2A-deletion doxorubicin-resistant Ewing's sarcoma patient-derived orthotopic xenograft (PDOX) nude-mouse model.

    PubMed

    Murakami, Takashi; Singh, Arun S; Kiyuna, Tasuku; Dry, Sarah M; Li, Yunfeng; James, Aaron W; Igarashi, Kentaro; Kawaguchi, Kei; DeLong, Jonathan C; Zhang, Yong; Hiroshima, Yukihiko; Russell, Tara; Eckardt, Mark A; Yanagawa, Jane; Federman, Noah; Matsuyama, Ryusei; Chishima, Takashi; Tanaka, Kuniya; Bouvet, Michael; Endo, Itaru; Eilber, Fritz C; Hoffman, Robert M

    2016-07-26

    Ewing's sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewing's sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewing's sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm3: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewing's sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer.

  7. Scotopic electroretinography in fishing cat (Prionailurus viverrinus) and leopard cat (Prionailurus bengalensis).

    PubMed

    Sussadee, Metita; Vorawattanatham, Narathip; Pinyopummin, Anuchai; Phavaphutanon, Janjira; Thayananuphat, Aree

    2017-05-01

    To establish baseline normal scotopic electroretinograpic (ERG) parameters for two wild cat species: fishing cats (FC) and leopard cats (LC). Twelve normal, FC and eight LC kept in the Chiang Mai Night Safari Zoo, Thailand. The mean ages of FC and LC were 7.08 and 5.00 years, respectively. All animals were studied using a standard scotopic protocol of a portable, handheld, multi-species electroretinography (HMsERG). There were significant differences in the means of ERG b-wave amplitude of the rod response (Rod, 0.01 cd.s/m 2 ), a- and b-wave amplitudes of standard light intensity of rod and cone response (Std R&C, 3 cd.s/m 2 ) and b-wave amplitude of high light intensity of rod and cone response (Hi-int R&C, 10 cd.s/m 2 ) with LC having higher amplitudes than FC. There was no significant difference in a- and b- wave implicit time except for the b-wave of Hi-int (P=0.03). No significant differences were observed in b/a amplitude ratios. Data from this report provides reference values for scotopic ERG measurements in these two wild cat species. It showed that the normal scotopic ERG responses have some differences between the two species which might be due to the skull conformation, eye size or physiology of the retina. © 2016 American College of Veterinary Ophthalmologists.

  8. The determination of dark adaptation time using electroretinography in conscious Miniature Schnauzer dogs

    PubMed Central

    Yu, Hyung-Ah; Jeong, Man-Bok; Park, Shin-Ae; Kim, Won-Tae; Kim, Se-Eun; Chae, Je-Min; Yi, Na-Young

    2007-01-01

    The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd·s/m2 was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p < 0.05). Thereafter, no significant differences in amplitude occured over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 ± 18.47 µV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p < 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 ± 17.79 µV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs. PMID:17993756

  9. Colliding neutron stars. Gravitational waves, neutrino emission, and gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Ruffert, M.; Janka, H.-Th.

    1998-10-01

    Three-dimensional hydrodynamical simulations are presented for the direct head-on or off-center collision of two neutron stars, employing a basically Newtonian PPM code but including the emission of gravitational waves and their back-reaction on the hydrodynamical flow. A physical nuclear equation of state is used that allows us to follow the thermodynamical evolution of the stellar matter and to compute the emission of neutrinos. Predicted gravitational wave signals, luminosities and waveforms, are presented. The models are evaluated for their implications for gamma-ray burst scenarios. We find an extremely luminous outburst of neutrinos with a peak luminosity of more than 4* 10(54) erg/s for several milliseconds. This leads to an efficiency of about 1% for the annihilation of neutrinos with antineutrinos, corresponding to an average energy deposition rate of more than 10(52) erg/s and a total energy of about 10(50) erg deposited in electron-positron pairs around the collision site within 10 ms. Although these numbers seem very favorable for gamma-ray burst scenarios, the pollution of the e(+/-) pair-plasma cloud with nearly 10(-1} M_{sun) of dynamically ejected baryons is 5 orders of magnitude too large. Therefore the formation of a relativistically expanding fireball that leads to a gamma-ray burst powered by neutrino emission from colliding neutron stars is definitely ruled out.

  10. Novel Phenotypic and Genotypic Findings in X-Linked Retinoschisis

    PubMed Central

    Tsang, Stephen H.; Vaclavik, Veronika; Bird, Alan C.; Robson, Anthony G.; Holder, Graham E.

    2009-01-01

    Objective To describe atypical phenotypes associated with the retinoschisis (X-linked, juvenile) 1 mutation (RS1). Methods Seven patients with multiple fine white dots at the macula and reduced visual acuity were evaluated. Six patients underwent pattern and full-field electroretinography (ERG). On-off ERG, optical coherence tomography, and fundus autofluorescence imaging were performed in some patients. Mutational screening of RS1 was prompted by the ERG findings. Results Fine white dots resembling drusenlike deposits and sometimes associated with retinal pigment epithelial abnormalities were present in the maculae. An electronegative bright-flash ERG configuration was present in all patients tested, and abnormal pattern ERG findings confirmed macular dysfunction. A parafoveal ring of high-density autofluorescence was present in 3 eyes; 1 patient showed high-density foci concordant with the white dots. Optical coherence tomography did not show foveal schisis in 3 of 4 eyes. All patients carried mutations in RS1, including 1 with a novel 206T→C mutation in exon 4. Conclusions Multiple fine white dots at the macula may be the initial fundus feature in RS1 mutation. Electrophysiologic findings suggest dysfunction after phototransduction and enable focused mutational screening. Autofluorescence imaging results suggest early retinal pigment epithelium involvement; a parafoveal ring of high-density autofluorescence has not previously been described in this disorder. PMID:17296904

  11. Squalene epoxidase as a target for manipulation of squalene levels in the yeast Saccharomyces cerevisiae.

    PubMed

    Garaiová, Martina; Zambojová, Veronika; Simová, Zuzana; Griač, Peter; Hapala, Ivan

    2014-03-01

    Squalene is a valuable natural substance with several biotechnological applications. In the yeast Saccharomyces cerevisiae, it is produced in the isoprenoid pathway as the first precursor dedicated to ergosterol biosynthesis. The aim of this study was to explore the potential of squalene epoxidase encoded by the ERG1 gene as the target for manipulating squalene levels in yeast. Highest squalene levels (over 1000 μg squalene per 10(9)  cells) were induced by specific point mutations in ERG1 gene that reduced activity of squalene epoxidase and caused hypersensitivity to terbinafine. This accumulation of squalene in erg1 mutants did not significantly disturb their growth. Treatment with squalene epoxidase inhibitor terbinafine revealed a limit in squalene accumulation at 700 μg squalene per 10(9)  cells which was associated with pronounced growth defects. Inhibition of squalene epoxidase activity by anaerobiosis or heme deficiency resulted in relatively low squalene levels. These levels were significantly increased by ergosterol depletion in anaerobic cells which indicated feedback inhibition of squalene production by ergosterol. Accumulation of squalene in erg1 mutants and terbinafine-treated cells were associated with increased cellular content and aggregation of lipid droplets. Our results prove that targeted genetic manipulation of the ERG1 gene is a promising tool for increasing squalene production in yeast. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd.

  12. Bevacizumab for metastatic colorectal cancer: a NICE single technology appraisal.

    PubMed

    Whyte, Sophie; Pandor, Abdullah; Stevenson, Matt

    2012-12-01

    The National Institute for Health and Clinical Excellence (NICE) invited the manufacturer of bevacizumab (Roche Products) to submit evidence for the clinical and cost effectiveness of this drug for the treatment of patients with metastatic colorectal cancer (mCRC), as part of the Institute's Single Technology Appraisal (STA) process. The School of Health and Related Research (ScHARR) at the University of Sheffield was commissioned to act as the Evidence Review Group (ERG). This paper provides a description of the company submission, the ERG review and NICE's subsequent decisions. The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology provided within the manufacturer's submission to NICE. The ERG also independently searched for relevant evidence and modified the manufacturer's decision analytic model to examine the impact of altering some of the key assumptions. The main clinical effectiveness data were derived from a phase III, multicentre, multinational, two-arm, randomized, open-label study with the primary objective of confirming the non-inferiority of oxaliplatin plus capecitabine (XELOX) compared with oxaliplatin plus 5-fluorouracil and folinic acid (FOLFOX-4) in adult patients with histologically confirmed mCRC who had not previously been treated. The ERG considered that the NO16966 trial was of reasonable methodological quality and demonstrated a significant improvement in both progression-free and overall survival when bevacizumab is added to either XELOX or FOLFOX-4. The ERG considered that the size of the actual treatment effect of bevacizumab was uncertain due to trial design limitations, imbalance of a known prognostic factor, relatively short treatment duration compared with that allowed within the trial protocol, and interpretation of the statistical analyses. The manufacturer's submission included a de novo economic evaluation using a cost-effectiveness model built in Microsoft® Excel. The ERG

  13. Initial report of the High Frequency Analyzer (HFA) onboard the ARASE (ERG) Satellite: Observations of the plasmasphere evolution and auroral kilometric radiation from the both hemisphere

    NASA Astrophysics Data System (ADS)

    Kumamoto, A.; Tsuchiya, F.; Kasahara, Y.; Kasaba, Y.; Kojima, H.; Yagitani, S.; Ishisaka, K.; Imachi, T.; Ozaki, M.; Matsuda, S.; Shoji, M.; Matsuoka, A.; Katoh, Y.; Miyoshi, Y.; Shinohara, I.; Obara, T.

    2017-12-01

    High Frequency Analyzer (HFA) is a subsystem of the Plasma Wave Experiment (PWE) onboard the ARASE (ERG, Exploration of energization and Radiation in Geospace) spacecraft for observation of radio and plasma waves in a frequency range from 0.01 to 10 MHz. In ARASE mission, HFA is expected to perform the following observations: (1) Upper hybrid resonance (UHR) waves in order to determine the electron number density around the spacecraft. (2) Magnetic field component of the chorus waves in a frequency range from 20 kHz to 100 kHz. (3) Radio and plasma waves excited via wave particle interactions and mode conversion processes in storm-time magnetosphere.HFA is operated in the following three observation modes: EE-mode, EB-mode, and PP-mode. In far-Earth region, HFA is operated in EE-mode. Spectrogram of two orthogonal or right and left-handed components of electric field in perpendicular directions to the spin axis of the spacecraft are obtained. In the near-Earth region, HFA is operated in EB-mode. Spectrogram of one components of electric field in perpendicular direction to the spin plane, and one component of the magnetic field in parallel direction to the spin axis are obtained. In EE and EB-modes, the frequency range from 0.01 to 10 MHz are covered with 480 frequency steps. The time resolution is 8 sec. We also prepared PP mode to measure the locations and structures of the plasmapause at higher resolution. In PP-mode, spectrogram of one electric field component in a frequency range from 0.01-0.4 MHz (PP1) or 0.1-1 MHz (PP2) can be obtained at time resolution of 1 sec.After the successful deployment of the wire antenna and search coils mast and initial checks, we could start routine observations and detect various radio and plasma wave phenomena such as upper hybrid resonance (UHR) waves, electrostatic electron cyclotron harmonic (ESCH) waves, auroral kilometric radiation (AKR), kilometric continuum (KC) and Type-III solar radio bursts. In the presentation, we

  14. Unique forbidden beta decays and neutrino mass

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dvornický, Rastislav, E-mail: dvornicky@dnp.fmph.uniba.sk; Comenius University, Mlynská dolina F1, SK-842 48 Bratislava; Šimkovic, Fedor

    The measurement of the electron energy spectrum in single β decays close to the endpoint provides a direct determination of the neutrino masses. The most sensitive experiments use β decays with low Q value, e.g. KATRIN (tritium) and MARE (rhenium). We present the theoretical spectral shape of electrons emitted in the first, second, and fourth unique forbidden β decays. Our findings show that the Kurie functions for these unique forbidden β transitions are linear in the limit of massless neutrinos like the Kurie function of the allowed β decay of tritium.

  15. X-Ray Emission from the Nuclear Region of Arp 220

    NASA Astrophysics Data System (ADS)

    Paggi, Alessandro; Fabbiano, Giuseppina; Risaliti, Guido; Wang, Junfeng; Karovska, Margarita; Elvis, Martin; Maksym, W. Peter; McDowell, Jonathan; Gallagher, Jay

    2017-05-01

    We present an imaging and spectral analysis of the nuclear region of the ultraluminous infrared galaxy merger of Arp 220, using deep Chandra-ACIS observations summing up to ˜ 300 {{ks}}. Narrowband imaging with subpixel resolution of the innermost nuclear region reveals two distinct Fe-K emitting sources, coincident with the infrared and radio nuclear clusters. These sources are separated by 1‧ (˜380 pc). The X-ray emission is extended and elongated in the eastern (E) nucleus, like the disk emission observed in millimeter radio images, suggesting a starburst dominance in this region. We estimate an Fe-K equivalent width of ≳ 1 {keV} for both sources and observe 2-10 keV luminosities of ˜ 2× {10}40 {{erg}} {{{s}}}-1 (western, W) and ˜ 3× {10}40 {{erg}} {{{s}}}-1 (E). In the 6-7 keV band the emission from these regions is dominated by the 6.7 keV Fe xxv line, suggesting a contribution from collisionally ionized gas. The thermal energy content of this gas is consistent with the kinetic energy injection in the interstellar medium by SNe II. However, nuclear winds from a hidden active galactic nucleus (AGN) (\\upsilon ˜ 2000 {{km}} {{{s}}}-1) cannot be excluded. The 3σ upper limits on the neutral Fe-Kα flux of the nuclear regions correspond to the intrinsic AGN 2-10 keV luminosities of < 1× {10}42 {{erg}} {{{s}}}-1 (W) and < 0.4× {10}42 {{erg}} {{{s}}}-1 (E). For typical AGN spectral energy distributions the bolometric luminosities are < 3× {10}43 {{erg}} {{{s}}}-1 (W) and < 8× {10}43 {{erg}} {{{s}}}-1 (E), and black hole masses of < 1× {10}5 {M}⊙ (W) and < 5× {10}5 {M}⊙ (E) are evaluated for Eddington limited AGNs with a standard 10% efficiency.

  16. What monitor can replace the cathode-ray tube for visual stimulation to elicit multifocal electroretinograms?

    PubMed

    Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Seki, Keisuke; Nagasaka, Eiichiro; Iwata, Takeshi; Mizota, Atsushi

    2014-08-05

    To compare a conventional cathode-ray tube (CRT) screen to organic light-emitting diode (OLED) and liquid crystal display (LCD) screens as visual stimulators to elicit multifocal electroretinograms (mfERGs), mfERGs were recorded from seven eyes of seven healthy volunteers (21 ± 2 years). The mfERGs elicited by a conventional CRT screen (S710, Compaq Computer Co.) were compared to those elicited by a studio-grade master OLED monitor (PVM-1741, Sony, Japan) and a conventional LCD (S1721, Flexscan, Eizo Nanao Corp., Japan). The luminance changes of each monitor were measured with a photodiode. CRT, OLED, and LCD screens with a frame frequency of 60 Hz were studied. A hexagonal stimulus array with 61 stimulus elements was created on each monitor. The serial white stimuli of the OLED screen at 60 Hz did not fuse, and that of the LCD screens fused. The amplitudes of P1 and P2 of the first-order kernels of the mfERGs were not significantly different from those elicited by the CRT and OLED screens, and the P1 amplitude of the first-order kernel elicited by the LCD stimuli was significantly smaller than that elicited by the CRT in all the groups of the averaged hexagonal elements. The implicit times were approximately 10 ms longer in almost all components elicited by the LCD screen compared to those elicited by the CRT screen. The mfERGs elicited by monitors other than the CRT should be carefully interpreted, especially those elicited by LCD screens. The OLED had good performance, and we conclude that it can replace the CRT as a stimulator for mfERGs; however, a collection of normative data is recommended. © 2014 ARVO.

  17. Extragalactic High-energy Transients: Event Rate Densities and Luminosity Functions

    NASA Astrophysics Data System (ADS)

    Sun, Hui; Zhang, Bing; Li, Zhuo

    2015-10-01

    Several types of extragalactic high-energy transients have been discovered, which include high-luminosity and low-luminosity long-duration gamma-ray bursts (GRBs), short-duration GRBs, supernova shock breakouts (SBOs), and tidal disruption events (TDEs) without or with an associated relativistic jet. In this paper, we apply a unified method to systematically study the redshift-dependent event rate densities and the global luminosity functions (GLFs; ignoring redshift evolution) of these transients. We introduce some empirical formulae for the redshift-dependent event rate densities for different types of transients and derive the local specific event rate density, which also represents its GLF. Long GRBs (LGRBs) have a large enough sample to reveal features in the GLF, which is best charaterized as a triple power law (PL). All the other transients are consistent with having a single-power-law (SPL) LF. The total event rate density depends on the minimum luminosity, and we obtain the following values in units of Gpc-3 yr-1: {0.8}-0.1+0.1 for high-luminosity LGRBs above 1050 erg s-1 {164}-65+98 for low-luminosity LGRBs above 5 × 1046 erg s-1 {1.3}-0.3+0.4, {1.2}-0.3+0.4, and {3.3}-0.8+1.0 above 1050 erg s-1 for short GRBs with three different merger delay models (Gaussian, lognormal, and PL); {1.9}-1.2+2.4× {10}4 above 1044 erg s-1 for SBOs, {4.8}-2.1+3.2× {10}2 for normal TDEs above 1044 erg s-1 and {0.03}-0.02+0.04 above 1048 erg s-1 for TDE jets as discovered by Swift. Intriguingly, the GLFs of different kinds of transients, which cover over 12 orders of magnitude, are consistent with an SPL with an index of -1.6.

  18. Monitoring the effect of mild ischemia with a built-in light-emitting diode contact lens electrode and a low-cost custom-made apparatus.

    PubMed

    Fleischman, A; Parvari, U; Oron, Y; Geyer, O

    2012-06-01

    Electroretinography (ERG) is widely used in clinical work and research to assess the retinal function. We evaluated an easy to build ERG setup adapted for small animals comprising two contact lens electrodes with a built-in light-emitting diode and a custom-made amplification system. The system's sensitivity was tested by monitoring ERG in albino rat eyes subjected to mild ischemia. Flash ERG was recorded by two contact lens electrodes positioned on the rat's corneas and used alternately as test or reference. The a- and b-wave amplitudes, a-wave latency, b-wave implicit time and oscillatory potentials (OPs) were analyzed. Ischemia was achieved by elevating the intraocular pressure in the eye's anterior chamber. ERG was recorded on post-ischemia (PI) days -1, 1, 3 and 7. Morphological changes were analyzed on hematoxylin/eosin stained 5 µm sections of control 7d PI retinas. In control eyes, ERG exhibited a pattern similar to a standard recording. Retinas subjected to mild ischemia preserved ordered layered morphology, exhibiting approximately 30% loss of ganglion cells and no changes in gross morphology. By day 3 PI, ischemia caused an increase in the a-wave amplitude (from 34.9 ± 2.7 to 45.4 ± 4.3 µV), a decrease in the b-wave amplitude (from 248 ± 13 to 162 ± 8 µV), an increase in a-wave latency (from 11.1 ± 0.3 to 17.3 ± 1.4 ms) and b-wave implicit time (from 81.0 ± 1.6 to 90.0 ± 2.5 ms), and attenuation of OPs. The described setup proved sensitive and reliable for evaluating subtle changes in the retinal function in small animals.

  19. Uplift, Feedback, and Buoyancy: Radio Lobe Dynamics in NGC 4472

    NASA Astrophysics Data System (ADS)

    Gendron-Marsolais, M.; Kraft, R. P.; Bogdan, A.; Hlavacek-Larrondo, J.; Forman, W. R.; Jones, C.; Su, Y.; Nulsen, P.; Randall, S. W.; Roediger, E.

    2017-10-01

    We present results from deep (380 ks) Chandra observations of the active galactic nucleus (AGN) outburst in the massive early-type galaxy NGC 4472. We detect cavities in the gas coincident with the radio lobes and estimate the eastern and western lobe enthalpy to be (1.1+/- 0.5)× {10}56 erg and (3+/- 1)× {10}56 erg and the average power required to inflate the lobes to be (1.8+/- 0.9)× {10}41 erg s-1 and (6+/- 3)× {10}41 erg s-1, respectively. We also detect enhanced X-ray rims around the radio lobes with sharp surface brightness discontinuities between the shells and the ambient gas. The temperature of the gas in the shells is less than that of the ambient medium, suggesting that they are not AGN-driven shocks but rather gas uplifted from the core by the buoyant rise of the radio bubbles. We estimate the energy required to lift the gas to be up to (1.1+/- 0.3)× {10}56 erg and (3+/- 1)× {10}56 erg for the eastern and western rims, respectively, constituting a significant fraction of the total outburst energy. A more conservative estimate suggests that the gas in the rim was uplifted at a smaller distance, requiring only 20%-25% of this energy. In either case, if a significant fraction of this uplift energy is thermalized via hydrodynamic instabilities or thermal conduction, our results suggest that it could be an important source of heating in cool core clusters and groups. We also find evidence for a central abundance drop in NGC 4472. The iron abundance profile shows that the region along the cavity system has a lower metallicity than the surrounding undisturbed gas, similar to the central region. This also shows that bubbles have lifted low-metallicity gas from the center.

  20. Characterization of macular structure and function in two Swedish families with genetically identified autosomal dominant retinitis pigmentosa

    PubMed Central

    Abdulridha-Aboud, Wissam; Kjellström, Ulrika; Andréasson, Sten

    2016-01-01

    Purpose To study the phenotype in two families with genetically identified autosomal dominant retinitis pigmentosa (adRP) focusing on macular structure and function. Methods Clinical data were collected at the Department of Ophthalmology, Lund University, Sweden, for affected and unaffected family members from two pedigrees with adRP. Examinations included optical coherence tomography (OCT), full-field electroretinography (ffERG), and multifocal electroretinography (mfERG). Molecular genetic screening was performed for known mutations associated with adRP. Results The mode of inheritance was autosomal dominant in both families. The members of the family with a mutation in the PRPF31 (p.IVS6+1G>T) gene had clinical features characteristic of RP, with severely reduced retinal rod and cone function. The degree of deterioration correlated well with increasing age. The mfERG showed only centrally preserved macular function that correlated well with retinal thinning on OCT. The family with a mutation in the RHO (p.R135W) gene had an extreme intrafamilial variability of the phenotype, with more severe disease in the younger generations. OCT showed pathology, but the degree of morphological changes was not correlated with age or with the mfERG results. The mother, with a de novo mutation in the RHO (p.R135W) gene, had a normal ffERG, and her retinal degeneration was detected merely with the reduced mfERG. Conclusions These two families demonstrate the extreme inter- and intrafamilial variability in the clinical phenotype of adRP. This is the first Swedish report of the clinical phenotype associated with a mutation in the PRPF31 (p.IVS6+1G>T) gene. Our results indicate that methods for assessment of the central retinal structure and function may improve the detection and characterization of the RP phenotype. PMID:27212874