744 research outputs found
Adoptive transfer of dendritic cells modulates immunogenesis and tolerogenesis in a neonatal model of murine cutaneous leishmaniasis
We evaluated the adoptive transfer of DCs on Leishmania (L.) mexicana-infected neonatal BALB/c mice. DCs were isolated and purified from the spleens of the following donor groups: a) Adult BALB/c mice infected during adulthood with L. (L) mexicana; b) Adult BALB/c mice infected during neonatal life; c) Healthy neonatal BALB/c mice; d) Healthy adult BALB/c mice. A neonatal model of infection, generated after inoculation with 5 × 10(5 )promastigotes of L. (L) mexicana, was used as the infection control group. Sixteen hours after intraperitoneal transfer of DCs (1 × 10(3), 1 × 10(5), or 1 × 10(6 )cells/ml), neonatal recipient BALB/c mice were infected. The adoptive transfer of DCs diminished disease progression in neonatal mice. This reduction depends on the quantity and provenance of transferred DCs, since the effect was more evident with high numbers of DCs from adult mice infected during adulthood and healthy neonatal mice. Protection was significantly reduced in animals receiving DCs from healthy adult mice but it was absent in mice receiving DCs from adult mice infected during neonatal life. These results suggest that genetic susceptibility to Leishmania infection can be modified during neonatal life, and that the period of life when antigens are encountered is crucial in influencing the capacity of DCs to induce resistance or tolerance
Estudio ultraestructural de la fagocitosis de promastigotes y amastigotes de Leishmania mexicana por la línea de células dendríticas FSDC
Introduction. Dendritic cells, which capture and present antigen to activate unprimed T cell, arefound in most tissues.Objective. This work describes the ultrastructure of Leishmania mexicana phagocytosis by thefetal skin dendritic cell (FSDC) line, a Langerhans cell line isolated from mouse fetal epidermisimmortalized by retroviral transduction of the v-myc oncogene.Materials and methods. Leishmania amastigotes were obtained from mouse (BALB/c) lesionand promastigotes from culture (24°C) of the lesion. FSDC cells were cultured with parasites (5parasites per cell) using IMDM medium, during 24 hours. Control and infected cultures wereprocessed for transmission electron microscopy. Semi-thin sections counterstained with toluidine blue to evaluate phagocytosis and thin sections counterstained with uranyl acetate and leadcitrate were made.Results. 13.42% of the FSDC phagocytosed promastigotes; 8% contained a single parasiteand 5.2% phagocytosed 2 or more. 20% of the FSDC phagocytosed amastigotes; 10% containeda single parasite and 10% phagocytosed 2 or more. Ultrastructurally, promastigotes in contactwith FSDC by the flagellum or the posterior pole were observed. The parasitophorous vacuolesharbouring promastigotes were small organelles containing one or two parasites each.Parasitophorous vacuoles containing amastigotes were larger (8μm diameter) with one orseveral parasites free or attached to the vacuole at the posterior pole.Conclusion. The low rate of infected FSDC cells was characteristic and the parasitophorousvacuole showed similar characteristics to those observed in macrophages. The parasite densityin the infected cells was 1 to 3 parasites per cell. These observations highlight the need to studythe relationship between phagocytic capacity and function.Introducción. Las células dendríticas están presentes en la mayoría de los tejidos, ellas capturany presentan antígenos para activar a los linfocitos T.Objetivo. Se describe ultraestructuralmente la fagocitosis de Leishmania mexicana por lalínea de células dendríticas FSDC, una línea de células de Langerhans obtenida de la epidermisfetal de ratón, e inmortalizada por la transducción retroviral del oncogen v-myc.Materiales y métodos. Se obtuvieron amastigotes de la lesión de ratones Balb/c y promastigotesa partir del cultivo (24°C) de la lesión. Las FSDC se cultivaron con los parásitos en unaproporción de 5 parásitos por célula, en medio IMDM, durante 24 horas. Los cultivos infectadosy los controles se procesaron para microscopía electrónica de transmisión. Se hicieron cortessemifinos contrastados con azul de toluidina para evaluar porcentaje de fagocitosis y finos,contrastados con acetato de uranilo y citrato de plomo.Resultados. El 13,42% de las FSDC fagocitaron promastigotes; de ellas el 8% contenían unparásito y el restante 5,2% fagocitó dos o más. El 20% de las FSDC fagocitaron amastigotes;10% contenían un parásito y 10% dos o más. Ultraestructuralmente se observaron promastigotesen contacto con las células por el flagelo o por el polo posterior. Los fagosomas que conteníanpromastigotes eran organelos estrechos con uno ó dos parásitos. Los que conteníanamastigotes eran de gran tamaño (8 μm) con uno o varios parásitos, libres o adosados a lamembrana del fagosoma por su polo posterior.Conclusión. La infección de las FSDC se caracterizó por una baja tasa de células infectadasal ser expuestas a promastigotes o amastigotes. La vacuola parasitofora presentó característicassimilares a las de los macrófagos. En su mayoría las FSDC presentaban 1 a 3 parásitos porcélula. Las observaciones plantean la necesidad de estudiar la relación entre capacidad defagocitosis y función
Anion Redox Chemistry in the Cobalt Free 3d Transition Metal Oxide Intercalation Electrode Li[LiNiMn]O
Conventional intercalation cathodes for lithium batteries store charge in redox reactions associated with the transition metal cations, e.g., Mn3+/4+ in LiMn2O4, and this limits the energy storage of Li-ion batteries. Compounds such as Li[Li0.2Ni0.2Mn0.6]O2 exhibit a capacity to store charge in excess of the transition metal redox reactions. The additional capacity occurs at and above 4.5 V versus Li+/Li. The capacity at 4.5 V is dominated by oxidation of the O2– anions accounting for ?0.43 e–/formula unit, with an additional 0.06 e–/formula unit being associated with O loss from the lattice. In contrast, the capacity above 4.5 V is mainly O loss, ?0.08 e–/formula. The O redox reaction involves the formation of localized hole states on O during charge, which are located on O coordinated by (Mn4+/Li+). The results have been obtained by combining operando electrochemical mass spec on 18O labeled Li[Li0.2Ni0.2Mn0.6]O2 with XANES, soft X-ray spectroscopy, resonant inelastic X-ray spectroscopy, and Raman spectroscopy. Finally the general features of O redox are described with discussion about the role of comparatively ionic (less covalent) 3d metal–oxygen interaction on anion redox in lithium rich cathode materials
Systematic review and meta-analysis on the adverse events of rimonabant treatment: Considerations for its potential use in hepatology
<p>Abstract</p> <p>Background</p> <p>The cannabinoid-1 receptor blockers have been proposed in the management of obesity and obesity-related liver diseases (fatty liver as NAFLD or NASH). Due to increasing number of patients to be potentially treated and the need to assess the advantage of this treatment in terms of risk/benefit, we analyze the side events reported during the treatment with rimonabant by a systematic review and meta-analysis of all randomized controlled studies.</p> <p>Methods</p> <p>All published randomized controlled trials using rimonabant <it>versus </it>placebo in adult subjects were retrieved. Relative risks (RR) with 95% confidence interval for relevant adverse events and number needed to harm was calculated.</p> <p>Results</p> <p>Nine trials (n = 9635) were considered. Rimonabant 20 mg was associated with an increased risk of adverse event (RR 1.35; 95%CI 1.17-1.56), increased discontinuation rate (RR 1.79; 95%CI 1.35-2.38), psychiatric (RR 2.35; 95%CI 1.66-3.34), and nervous system adverse events (RR 2.35; 95%CI 1.49-3.70). The number needed to harm for psychiatric adverse events is 30.</p> <p>Conclusion</p> <p>Rimonabant is associated with an increased risk of adverse events. Despite of an increasing interest for its use on fatty liver, the security profile and efficacy it is needs to be carefully assessed before its recommendation. At present the use of rimonabant on fatty liver cannot be recommended.</p
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
Immunization against Leishmania major Infection Using LACK- and IL-12-Expressing Lactococcus lactis Induces Delay in Footpad Swelling
BACKGROUND: Leishmania is a mammalian parasite affecting over 12 million individuals worldwide. Current treatments are expensive, cause severe side effects, and emerging drug resistance has been reported. Vaccination is the most cost-effective means to control infectious disease but currently there is no vaccine available against Leishmaniasis. Lactococcus lactis is a non-pathogenic, non-colonizing Gram-positive lactic acid bacterium commonly used in the dairy industry. Recently, L. lactis was used to express biologically active molecules including vaccine antigens and cytokines. METHODOLOGY/PRINCIPAL FINDINGS: We report the generation of L. lactis strains expressing the protective Leishmania antigen, LACK, in the cytoplasm, secreted or anchored to the bacterial cell wall. L. lactis was also engineered to secrete biologically active single chain mouse IL-12. Subcutaneous immunization with live L. lactis expressing LACK anchored to the cell wall and L. lactis secreting IL-12 significantly delayed footpad swelling in Leishmania major infected BALB/c mice. The delay in footpad swelling correlated with a significant reduction of parasite burden in immunized animals compared to control groups. Immunization with these two L. lactis strains induced antigen-specific multifunctional T(H)1 CD4(+) and CD8(+) T cells and a systemic LACK-specific T(H)1 immune response. Further, protection in immunized animals correlated with a Leishmania-specific T(H)1 immune response post-challenge. L. lactis secreting mouse IL-12 was essential for directing immune responses to LACK towards a protective T(H)1 response. CONCLUSIONS/SIGNIFICANCE: This report demonstrates the use of L. lactis as a live vaccine against L. major infection in BALB/c mice. The strains generated in this study provide the basis for the development of an inexpensive and safe vaccine against the human parasite Leishmania
Vitamin D and risk of pregnancy related hypertensive disorders: Mendelian randomisation study
Objective To use mendelian randomisation to investigate whether 25-hydroxyvitamin D concentration has a causal effect on gestational hypertension or pre-eclampsia. Design One and two sample mendelian randomisation analyses. Setting Two European pregnancy cohorts (Avon Longitudinal Study of Parents and Children, and Generation R Study), and two case-control studies (subgroup nested within the Norwegian Mother and Child Cohort Study, and the UK Genet
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