Linfoma de células T/natural killer extranodal de tipo nasal enmascarado en una sinusopatía

Introducción: El linfoma de células T citotóxico/natural killer extranodal de tipo nasal es poco frecuente, pero con alta tasa de mortalidad. Las manifestaciones clínicas de la enfermedad pueden simular una infección de senos paranasales. Objetivo: Presentar las manifestaciones clínicas de un paciente de 34 años de edad con diagnóstico de linfoma de células T citotóxico/ natural killer extranodal de tipo nasal. Caso clínico: Se presenta un paciente masculino de 34 años de edad con rinorrea verdosa fétida recurrente y obstrucción en fosa nasal derecha. En la evaluación inicial sugiere sinusitis crónica, sin embargo, debido al empeoramiento de las manifestaciones clínicas se realiza una tomografía computarizada que muestra lesiones sugestivas de infiltración neoplásica, una biopsia de la lesión confirma el diagnóstico de linfoma de células T/natural killer extranodal de tipo nasal. Conclusiones: Los linfomas de células T citotóxico/natural killer extranodal de tipo nasal son considerados neoplasias poco frecuentes, caracterizadas por el patrón rápidamente progresivo con afectación ósea; en su etapa inicial presenta manifestaciones clínicas similares a una sinusitis. La tomografía computarizada y la histopatología, son indispensables en el diagnóstico de la enfermedad

Signal pathways underlying homocysteine-induced production of MCP-1 and IL-8 in cultured human whole blood

Aim : To elucidate the mechanisms underlying homocysteine (Hcy)-induced chemokine production. Methods : Human whole blood was pretreated with inhibitors of calmodulin (CaM), protein kinase C (PKC), protein tyrosine kinase (PTK), mitogen-activated protein kinase (MAPK), and NF-ΚB and activators of PPARΓ for 60 min followed by incubation with Hcy 100 Μmol/L for 32 h. The levels of mitogen chemokine protein (MCP)-1 and interleukin-8 (IL-8) were determined by enzyme-linked immunosorbant assay (ELISA). Results : Inhibitors of PKC (calphostin C, 50-500 nmol/L and RO-31-8220, 10–100 nmol/L), CaM (W7, 28–280 Μmol/L), ERK1/2 MAPK (PD 98059, 2–20 Μmol/L), p38 MAPK (SB 203580, 0.6–6 Μmol/L), JNK MAPK (curcumin, 2–10 Μmol/L), and NF-ΚB (PDTC, 10-100 nmol/L) markedly reduced Hcy 100 Μmol/L-induced production of MCP-1 and IL-8 in human cultured whole blood, but the inhibitors of PTK (genistein, 2.6–26 Μmol/L and tyrphostin, 0.5-5 Μmol/L) had no obvious effect on MCP-1 and IL-8 production. PPARΓ activators (ciglitazone 30 Μmol/L and troglitazone 10 Μmol/L) depressed the Hcy-induced MCP-1 production but not IL-8 production in the cultured whole blood. Conclusion : Hcy-induced MCP-1 and IL-8 production is mediated by activated signaling pathways such as PKC, CaM, MAPK, and NF-ΚB. Our results not only provide clues for the signal transduction pathways mediating Hcy-induced chemokine production, but also offer a plausible explanation for a pathogenic role of hyperhomocysteinemia in these diseases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75644/1/j.1745-7254.2005.00005.x.pd

Progresso realizado pelo Agrosalud no aumento do conteúdo de ferro e zinco em grão de arroz.

A abordagem 'fast-track' está sendo utilizada na escolha de linhagens e variedades tradicionais/melhoradas de arroz com elevados teores de ferro e zinco no grão. 5.743 amostras, incluindo linhagens melhoradas do CIAT e NARs, foram analisadas quanto ao conteúdo de ferro e zinco pelo método de absorção atômica. Algumas linhagens apresentaram entre 5 e 7 ppm de ferro, e estão sendo avaliadas para adaptação local pelos colaboradores do AgroSalud. No Brasil, a Embrapa identificou variedades locais com até 12.6 e 42.2 ppm de ferro e zinco, respectivamente, que estão sendo utilizadas como genitores de novas cultivares. Atividades de melhoramento estão sendo realizadas na Colômbia, República Dominicana, Brasil, Cuba, Nicarágua, Bolívia, Panamá e no CIAT, atendendo ao objetivo de lançar cultivares biofortificadas em 2009-2010.Resumo também em inglês

The 2HWC HAWC Observatory Gamma Ray Catalog

We present the first catalog of TeV gamma-ray sources realized with the recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the most sensitive wide field-of-view TeV telescope currently in operation, with a 1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an instantaneous field of view >1.5 sr and >90% duty cycle, it continuously surveys and monitors the sky for gamma ray energies between hundreds GeV and tens of TeV. HAWC is located in Mexico at a latitude of 19 degree North and was completed in March 2015. Here, we present the 2HWC catalog, which is the result of the first source search realized with the complete HAWC detector. Realized with 507 days of data and represents the most sensitive TeV survey to date for such a large fraction of the sky. A total of 39 sources were detected, with an expected contamination of 0.5 due to background fluctuation. Out of these sources, 16 are more than one degree away from any previously reported TeV source. The source list, including the position measurement, spectrum measurement, and uncertainties, is reported. Seven of the detected sources may be associated with pulsar wind nebulae, two with supernova remnants, two with blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR

Very high energy particle acceleration powered by the jets of the microquasar SS 433

SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of $\sim0.26c$ extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets. SS 433 differs from other microquasars in that the accretion is believed to be super-Eddington, and the luminosity of the system is $\sim10^{40}$ erg s$^{-1}$. The lobes of W50 in which the jets terminate, about 40 pc from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed. At higher energies (>100 GeV), the particle fluxes of $\gamma$ rays from X-ray hotspots around SS 433 have been reported as flux upper limits. In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons interacting with the ambient gas. Here we report TeV $\gamma$-ray observations of the SS 433/W50 system where the lobes are spatially resolved. The TeV emission is localized to structures in the lobes, far from the center of the system where the jets are formed. We have measured photon energies of at least 25 TeV, and these are certainly not Doppler boosted, because of the viewing geometry. We conclude that the emission from radio to TeV energies is consistent with a single population of electrons with energies extending to at least hundreds of TeV in a magnetic field of $\sim16$~micro-Gauss.Comment: Preprint version of Nature paper. Contacts: S. BenZvi, B. Dingus, K. Fang, C.D. Rho , H. Zhang, H. Zho

Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC

We present results from daily monitoring of gamma rays in the energy range $\sim0.5$ to $\sim100$ TeV with the first 17 months of data from the High Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2 steradians and duty cycle of $>95$% are unique features compared to other TeV observatories that allow us to observe every source that transits over HAWC for up to $\sim6$ hours each sidereal day. This regular sampling yields unprecedented light curves from unbiased measurements that are independent of seasons or weather conditions. For the Crab Nebula as a reference source we find no variability in the TeV band. Our main focus is the study of the TeV blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a power law index $\Gamma=2.21 \pm0.14_{\mathrm{stat}}\pm0.20_{\mathrm{sys}}$ and an exponential cut-off $E_0=5.4 \pm 1.1_{\mathrm{stat}}\pm 1.0_{\mathrm{sys}}$ TeV. For Mrk 501, we find an index $\Gamma=1.60\pm 0.30_{\mathrm{stat}} \pm 0.20_{\mathrm{sys}}$ and exponential cut-off $E_0=5.7\pm 1.6_{\mathrm{stat}} \pm 1.0_{\mathrm{sys}}$ TeV. The light curves for both sources show clear variability and a Bayesian analysis is applied to identify changes between flux states. The highest per-transit fluxes observed from Mrk 421 exceed the Crab Nebula flux by a factor of approximately five. For Mrk 501, several transits show fluxes in excess of three times the Crab Nebula flux. In a comparison to lower energy gamma-ray and X-ray monitoring data with comparable sampling we cannot identify clear counterparts for the most significant flaring features observed by HAWC.Comment: 18 pages, 10 figures, accepted for publication in The Astrophysical Journa

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

The unexpectedly high flux of cosmic ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the HighAltitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.Comment: 16 pages (including supplementary material), 5 figure