Constraints on Sub-GeV Dark-Matter-Electron Scattering from the DarkSide-50 Experiment.

We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100 MeV/c^{2}.

Low-Mass Dark Matter Search with the DarkSide-50 Experiment.

We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20 GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso. The analysis is based on the ionization signal, for which the DarkSide-50 time projection chamber is fully efficient at 0.1 keVee. The observed rate in the detector at 0.5 keVee is about 1.5 event/keVee/kg/d and is almost entirely accounted for by known background sources. We obtain a 90% C.L. exclusion limit above 1.8 GeV/c^{2} for the spin-independent cross section of dark matter WIMPs on nucleons, extending the exclusion region for dark matter below previous limits in the range 1.8-6 GeV/c^{2}.

Quantitative phase retrieval with picosecond X-ray pulses from the ATF Inverse Compton Scattering source.

Quantitative phase retrieval is experimentally demonstrated using the Inverse Compton Scattering X-ray source available at the Accelerator Test Facility (ATF) in the Brookhaven National Laboratory. Phase-contrast images are collected using in-line geometry, with a single X-ray pulse of approximate duration of one picosecond. The projected thickness of homogeneous samples of various polymers is recovered quantitatively from the time-averaged intensity of transmitted X-rays. The data are in good agreement with the expectations showing that ATF Inverse Compton Scattering source is suitable for performing phase-sensitive quantitative X-ray imaging on the picosecond scale. The method shows promise for quantitative imaging of fast dynamic phenomena.

Grainyhead-like Transcription Factors in Craniofacial Development.

Craniofacial development in vertebrates involves the coordinated growth, migration, and fusion of several facial prominences during embryogenesis, processes governed by strict genetic and molecular controls. A failure in any of the precise spatiotemporal sequences of events leading to prominence fusion often leads to anomalous facial, skull, and jaw formation-conditions termed craniofacial defects (CFDs). Affecting approximately 0.1% to 0.3% of live births, CFDs are a highly heterogeneous class of developmental anomalies, which are often underpinned by genetic mutations. Therefore, identifying novel disease-causing mutations in genes that regulate craniofacial development is a critical prerequisite to develop new preventive or therapeutic measures. The Grainyhead-like ( GRHL) transcription factors are one such gene family, performing evolutionarily conserved roles in craniofacial patterning. The antecedent member of this family, Drosophila grainyhead ( grh), is required for head skeleton development in fruit flies, loss or mutation of Grhl family members in mouse and zebrafish models leads to defects of both maxilla and mandible, and recently, mutations in human GRHL3 have been shown to cause or contribute to both syndromic (Van Der Woude syndrome) and nonsyndromic palatal clefts. In this review, we summarize the current knowledge regarding the craniofacial-specific function of the Grainyhead-like family in multiple model species, identify some of the major target genes regulated by the Grhl transcription factors in craniofacial patterning, and, by examining animal models, draw inferences as to how these data will inform the likely roles of GRHL factors in human CFDs comprising palatal clefting. By understanding the molecular networks regulated by Grhl2 and Grhl3 target genes in other systems, we can propose likely pathways that mediate the effects of these transcription factors in human palatogenesis.

Anti-apoptotic gene Bcl2 is required for stapes development and hearing.

In this paper we describe novel and specific roles for the apoptotic regulators Bcl2 and Bim in hearing and stapes development. Bcl2 is anti-apoptotic while Bim is pro-apoptotic. Characterization of the auditory systems of mice deficient for these molecules revealed that Bcl2⁻/⁻ mice suffered severe hearing loss. This was conductive in nature and did not affect sensory cells of the inner ear, with cochlear hair cells and neurons present and functional. Bcl2⁻/⁻ mice were found to have a malformed, often monocrural, porous stapes (the small stirrup-shaped bone of the middle ear), but a normally shaped malleus and incus. The deformed stapes was discontinuous with the incus and sometimes fused to the temporal bones. The defect was completely rescued in Bcl2⁻/⁻Bim⁻/⁻ mice and partially rescued in Bcl2⁻/⁻Bim⁺/⁻ mice, which displayed high-frequency hearing loss and thickening of the stapes anterior crus. The Bcl2⁻/⁻ defect arose in utero before or during the cartilage stage of stapes development. These results implicate Bcl2 and Bim in regulating survival of second pharyngeal arch or neural crest cells that give rise to the stapes during embryonic development.

Niveles séricos de inmunoglobulinas en niños con infecciones a repetición / Serum immunoglobulin levels in children with recurrent infections

Las infecciones a repetición en niños, se deben generalmente a trastornos en la inmunidad humoral. El objetivo del trabajo fue evaluar los niveles séricos de inmunoglobulinas en niños con infecciones a repetición. Se incluyeron 17 niños (6 mujeres y 11 varones), con una edad promedio de 5 años (0 a 14 años), en el periodo comprendido de marzo de 2006 a julio de 2007. Previo consentimiento de los padres, se recolectaron los datos en una ficha y se tomaron las muestras de sangre. La determinación del nivel de inmunoglobulina se realizó por los métodos de Inmunodifusión radial y quimioluminiscencia. Las neumonías fueron las infecciones referidas más frecuentes. Se encontraron niveles de IgA < 5 mg/dl en 2 pacientes (12 %); IgG < 400 mg/dl en 2 pacientes (12 %); IgM > 250 mg/dl en 11 pacientes (64,7 %) y niveles de IgE > 91 mg/dl en 13 pacientes (77 %). En esta serie de 17 pacientes con infecciones a repetición se ha encontrado dos pacientes (12%), con diagnóstico de Inmunodeficiencia primaria con déficit de IgG. La evaluación del estado inmunológico de los pacientes con infecciones a repetición es de gran importancia, porque contribuye al diagnóstico precoz que mejora el pronóstico y previene de posibles complicaciones a los pacientes.

Recurrent infections in children are usually due to humoral immunity disorders. Our objective was to determine serum immunoglobulin levels in children with recurrent infections. We included 17 children (six females and 11 males) with an average age of 5 years (0-14 years) during the period of March 2006 to July 2007. After parental consent, we recorded their data on a chart and took blood samples. Determination of immunoglobulin levels was done by radial immunodiffusion and chemiluminescence. Pneumonia was the most frequently reported type of infection. IgA levels found were <5 mg/dl in 2 patients (12%); IgG <400 mg/dl in 2 patients (12%); IgM >250 mg/dl in 11 patients (64.7%), and IgE levels >91 mg/dl in 13 patients (77%).In this series of 17 patients with recurrent infections we found two patients (12%) diagnosed with primary immunodeficiency involving IgG deficiency. Immunological assessment of patients with recurrent infections is of great importance because it helps reach early diagnosis that improves prognosis and helps avoids complications for patients.

Niveles séricos de factor de necrosis tumoral-α e interferón-γ en pacientes con dengue febril / Serum levels of tumor necrosis factor-α and interferon-γ in patients with dengue

Los monocitos/macrófagos constituyen las células diana para el virus dengue, activando linfocitos T, liberando citoquinas proinflamatorias como el Factor de Necrosis Tumoral alfa e Interferón gamma. El objetivo del estudio fue determinar TNF-α e IFN-γ en suero de pacientes dengue IgM positivo e IgM negativo, que concurrieron al Instituto de Investigaciones en Ciencias de la Salud, de febrero a abril 2007. Se realizó un estudio analítico en 163 sueros de pacientes con dengue, 143 IgM positivo y 20 IgM negativo, de ambos sexos con edad promedio de 30 y rango entre 18 a 70 años. El anticuerpo IgM para dengue y las citoquinas fueron determinados por ELISA de captura. En los 143 sueros dengue IgM positivo, el IFN-γ se detectó en 73% (104/143) con valores entre 558 y superiores a 2000 pg/ml y en el 27% (39/143) valores por debajo del punto de corte. Se encontró una diferencia estadísticamente significativa comparado con sueros dengue IgM negativo (p = < 0.005). El TNF-α se detectó en 24% (35/143) sueros IgM positivo, de los cuales 33 presentaron valores entre 45 a 176 pg/ml y 2 con valores superiores a 2000 pg/ml. No hubo significancia estadística comparando con sueros dengue IgM negativo (p = 0.26). Niveles elevados de IFN-γ y TNF-α podrían ser considerados marcadores de pronóstico para la progresión al dengue hemorrágico. Se debería tener en cuenta la potencial significancia terapéutica de estas citoquinas que podrían ayudar en las estrategias de inhibir o inducir perfiles de citoquinas adecuadas en respuesta al dengue.

Monocytes/macrophages are target cells for dengue virus, taking part in the activation of T lymphocytes, releasing proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). The objective of this study was to determine TNF-α and IFN-γ in sera of dengue patients with IgM positive and negative who attended the Instituto de Investigaciones en Ciencias de la Salud from February to April 2007. An analytical study was performed in 163 sera of dengue patients, 143 IgM positive and 20 IgM negative, men and women with an mean age of 30 years and a range from 18 to 70 years. The IgM antibody for dengue and the serum levels of cytokines were performed by capture ELISA. Serum levels of IFN-γ were detected in 73% (104/143) of the patients with dengue IgM positive, with values between 558 and higher than 2000 pg/ml, and in 27% (39/143) were below the cut-off value. A statistically significative difference was found when they were compared with dengue IgM negative sera (p=<0.005). TNF-α serum levels were detected in 24% (35/143) of the dengue IgM positive patients, 33 patients presented values between 45 and 176 pg/ml and 2 had values above 2000 pg/ml. No statistical significance was found when these values were compared with those of dengue IgM negative sera (p=0.26). IFN-γ and TNF-α high levels could be considered prognostic markers for progression to hemorrhagic dengue. The potential therapeutic significance of these cytokines should be considered as they could help in the strategies to inhibit or induce appropriate cytokine profiles in response to dengue virus.

Frecuencia de los patrones de anticuerpos anti-nucleares en pacientes con sospecha clínica de LES / Frequency of antinuclear antibody patterns in patients with SLE clinical suspicion

Las enfermedades autoinmunes son alteraciones de los mecanismos de tolerancia inmunológica, con producción de anticuerpos contra antígenos propios, como los anticuerpos antinucleares (ANA), que detectados por inmunofluorescencia indirecta,permiten reconocer varios patrones nucleares y citoplasmáticos, como en el Lupus Eritematoso Sistémico (LES). El objetivo del estudio fue describir los patrones de tinciónde ANA en sueros de pacientes con sospecha clínica de LES, que concurrieron al Instituto de Investigaciones en Ciencias de la Salud, durante el año 2008. En este estudio observacional descriptivo, se analizaron 150 sueros positivos para ANA, codificados,respetando la confidencialidad de los mismos. Para la determinación de ANA se utilizaron láminas con células HEp-2 (BIO-RAD-USA), y el conjugado fue anti human IgG de Sigma(USA); la técnica fue inmunofluorescencia indirecta. Del total de 150 pacientes estudiados, 134 (89%) fueron mujeres y 16 (11%) hombres, cuyas edades estaban comprendidas entre 11 y 87 años. De los sueros positivos analizados para ANA, 44 (29%)correspondieron al patrón periférico, 18(12%) puntillado grueso, 39(26%) puntillado fino,42(28%) homogéneo, 5(3%) nucleolar y 2(1.3%) citoplásmico puntillado fino. En este estudio se encontró en mayor porcentaje el patrón periférico, seguido del homogéneo y puntillado fino, los cuales se hallan asociados a pacientes con LES, indicando un pronóstico poco favorable para estos pacientes.

Autoimmune diseases are alterations of the immunological tolerance mechanisms, with production of antibodies against self-antigens, such as antinuclear antibodies (ANA), which are detected by indirect immunofluorescence, and allow the recognition of several nuclear and cytoplasmic patterns, as shown in the systemic lupus erythematosus (SLE).The objective of this study was to describe the ANA staining patterns in sera of patients with clinical suspicion of SLE that attended the Instituto de Investigaciones en Ciencias de la Salud during 2008. In this descriptive observational study, 150 coded positive ANA sera were analyzed, respecting the confidentiality of patients. ANA determination was made by indirect immunofluorescence using slides with HEp-2 cells (BIO-RAD-USA) and aantihuman-IgG-fluorescein conjugate from Sigma (USA). Of the 150 studied patients, 134 (89%) were females and 16 (11%) males with ages between 11 and 87 years. Of the ANA positive sera analyzed, 44 (29%) showed peripheral patterns, 18 (12%) coarse speckled patterns, 39 (26%) fine speckled patterns, 42 (28%) homogeneous patterns, 5 (3%) nucleolar patterns and 2 (1.3%) fine speckled cytoplasmic patterns. In this study, the peripheral pattern was found in greater percentage, followed by homogeneous and fine speckled patterns, which are associated to patients with SLE, indicating an unfavorable prognosis for these patients.

Concordancia entre las pruebas de ELISA avidez IgG desarrollados en el Instituto de Investigaciones en Ciencias de la Salud y un ELISA avidez comercial / Concordance between the IgG avidity ELISA tests developed at the Instituto de Investigaciones en Ciencias de la Salud and a commercial avidity ELISA

La infección aguda de toxoplasmosis en la mujer durante el embarazo en su mayor parte es asintomática y detectable solo por anticuerpos lo que podría afectar severamenteal feto si no es diagnosticada y tratada precozmente. En este estudio observacionalanalítico de corte transverso se comparó la prueba de ELISA Avidez IgG paratoxoplasmosis desarrollado en el Instituto de Investigaciones en Ciencias de la Salud(IICS) con un test comercial de avidez InmunoLISA Organics USA. Para la concordanciase utilizó 41 sueros mantenidos a -20 ºC procedentes de la seroteca del Departamento de Producción-Bioquímica seleccionados al azar. La concordancia obtenida fue de 92.7% y un índice de Kappa de 0.820 con IC95% (0.6-1) y p<0.0001. El índice bajo de avidez sugiere una infección aguda pero para el diagnóstico debería estar acompañado de otras pruebas serológicas y la clínica del paciente. En cambio un índice alto es diagnóstico de una infección crónica.

The acute infection caused by Toxoplasma gondii in pregnant women is mostly asymptomatic and detectable only by antibodies that could severely affect the fetus if the infection is not diagnosed and treated precociously. In this cross-sectional observational,the analytical the IgG avidity ELISA test for toxoplasmosis, developed at the Instituto de Investigaciones en Ciencias de la Salud (IICS), was compared to a commercial avidity kit InmunoLISA (Organics, USA). For the concordance, 41 serum samples kept at -20ºC atthe Department of Production-Biochemistry of IICS were tested. The concordance obtained was 92.7% and a Kappa index of 0.820 with IC95% (0.6-1) and p <0.0001. The low avidity index suggests an acute infection but for diagnosis this result should beaccompanied by other serologic tests and clinical symptoms. Instead, a high avidity index suggests a chronic infection.

Concordancia de antígenos de dengue en el ELISA de captura de IgM (MAC ELISA) en el IICS-UNA / Concordance of dengue antigens M antibody-capture ELISA (MAC ELISA) in the IICS-UNA

El dengue es una enfermedad aguda grave considerada actualmente como infección reemergente, cuyo vector principal es el Aedes aegypti. En Paraguay en el 2007 fueron reportados 28.181 casos, 55 se clasificaron como fiebre hemorrágica del dengue de los cuales 7 fallecieron. El 90% de los casos fueron de Asunción y del Departamento Central,10% del resto del país. En los últimos años se han desarrollado diferentes sistemas inmunoenzimáticos para el diagnóstico del dengue, entre ellos el ELISA de captura de IgM (MAC ELISA). El objetivo de este estudio observacional analítico de corte transverso fu ecomparar la prueba del MAC ELISA desarrollada en el Instituto de Investigaciones en Ciencias de la Salud (IICS) utilizando antígenos suministrados por el Instituto Pedro Kouri(IPK) de Cuba y el Evandro Chagas de Brasil, con el kit comercial ELISA IgM por capturapara virus del dengue (Focus Diagnostics Inc. Cypress, CA, USA). Fueron seleccionados alazar 92 sueros de pacientes codificados que concurrieron al IICS con sospecha de dengue, respetándose la confidencialidad de los mismos. La concordancia obtenida fue del94.6% (Índice Kappa: 0.891) utilizando el antígeno del IPK y 96.7% (Índice Kappa:0.9350) con el antígeno del Evandro Chagas, mostrándose alta significancia estadística(p<0.00001) en ambos casos. La excelente concordancia obtenida con los dos antígenos indica que los mismos pueden ser utilizados indistintamente en la prueba del MAC ELISA desarrollada en el IICS, a fin de apoyar el diagnóstico del dengue a menor costo y quesería de producción local.

Dengue is an acute disease currently considered a re-emerging infection, whose main vector is Aedes aegypti. In 2007, 28,181 cases were reported in Paraguay, 55 were classified as dengue hemorrhagic fever and seven of them died. Ninety percent of the cases were from Asunción and the Central Department and the remaining 10% from the rest of the country. In recent years various immunoenzymatic systems have been developed immunoassay for the diagnosis of dengue, including the M antibody captureELISA (MAC ELISA). The aim of this cross-sectional observational study was to compare the MAC ELISA test developed at the Instituto de Investigaciones en Cienciad de la Salud(IICS) using antigens supplied by the Instituto Pedro Kouri (IPK) of Cuba and Evandro Chagas of Brazil with a commercial kit of M antibody capture ELISA for dengue virus (Focus Diagnostics Inc. Cypress, CA, USA). Ninety two coded serum samples wererandomly selected from patients who attended the IICS with suspected dengue, respecting their confidentiality. The concordance obtained was 94.6% (Kappa Index: 0.891) using the IPK antigen and 96.7% (Kappa index: 0.9350) with the antigen from Evandro Chagas showing high statistical significance (p<0.00001) in both cases. The excellent concordance obtained with the two antigens indicates that they can be used indistinctly in the MAC ELISA test developed in the IICS to support the diagnosis of dengue at a lower cost and would be locally produced.