Malarial pigment haemozoin, IFN-gamma, TNF-alpha, IL-1beta and LPS do not stimulate expression of inducible nitric oxide synthase and production of nitric oxide in immuno-purified human monocytes

<p>Abstract</p> <p>Background</p> <p>Enhanced production of nitric oxide (NO) following upmodulation of the inducible isoform of NO synthase (iNOS) by haemozoin (HZ), inflammatory cytokines and LPS may provide protection against <it>Plasmodium falciparum </it>malaria by killing hepatic and blood forms of parasites and inhibiting the cytoadherence of parasitized erythrocytes (RBC) to endothelial cells. Monocytes and macrophages are considered to contribute importantly to protective upregulation of iNOS and production of NO. Data obtained with murine phagocytes fed with human HZ and synthetic HZ (sHZ) indicate that supplemental treatment of those cells with IFN-gamma elicited significant increases in protein and mRNA expression of iNOS and NO production, providing a potential mechanism linking HZ phagocytosis and increased production of NO. Purpose of this study was to analyse the effect of <it>P. falciparum </it>HZ and sHZ supplemental to treatment with IFN-gamma and/or a stimulatory cytokine-LPS mix on iNOS protein and mRNA expression in immuno-purified human monocytes.</p> <p>Methods</p> <p>Adherent immunopurified human monocytes (purity >85%), and murine phagocytic cell lines RAW 264.7, N11 and ANA1 were fed or not with <it>P. falciparum </it>HZ or sHZ and treated or not with IFN-gamma or a stimulatory cytokine-LPS mix. Production of NO was quantified in supernatants, iNOS protein and mRNA expression were measured after immunoprecipitation and Western blotting and quantitative RT-PCT, respectively.</p> <p>Results</p> <p>Phagocytosis of HZ/sHZ by human monocytes did not increase iNOS protein and mRNA expression and NO production either after stimulation by IFN-gamma or the cytokine-LPS mix. By contrast, in HZ/sHZ-laden murine macrophages, identical treatment with IFN-gamma and the cytokine-LPS mix elicited significant increases in protein and mRNA expression of iNOS and NOS metabolites production, in agreement with literature data.</p> <p>Conclusion</p> <p>Results indicate that human monocytes fed or not with HZ/sHZ were constantly unable to express iNOS and generate NOS metabolites even after stimulation with IFN-gamma or a cytokine-LSP mix that were very active on HZ-fed murine phagocytic lines. Present data do not support the hypothesis that monocytes are mediators of anti-parasitic defence in clinical malaria via activation of iNOS and production of NO, and suggest caution in extrapolating data obtained with murine or hybrid systems to human malaria.</p

Recent results from Pb-Au collisions at 158 GeV/c per nucleon obtained with the CERES spectrometer

During the 1996 lead run time, CERES has accumulated 42 million events, corresponding to a factor of 5 more statistics than in 1995 and 2.5 million events of a special photon-run. We report on the results of the low-mass e$^+$e$^-$-pair analysis. Since the most critical item is the poor signal-to-background ratio we also discuss the understanding of this background, in absolute terms, with the help of a detailed Monte Carlo simulation. We show preliminary results of the photon analysis and summarize the results of the hadron analysis preliminarily reported on already at QM'97Comment: 10 pages, 9 figures, Proceedings of the XIV Int. Conf. on Nucleus-Nucleus Collisions,Quark Matter 99, Torino, Italy, May 10 - 15, 199

Cartografiar el conocimiento en la Universidad hoy. Una investigación de caso en la perspectiva compleja

te artículo asume procesos y resultados de una investigación sobre el conocimiento en la universidad desde la perspectiva compleja. Presenta el “caso” de una carrera universitaria. Se trabaja la trama teoría-práctica, a la luz de las evidencias provenientes de las fuentes de diferentes actores, tomando, a la universidad como institución auto-eco-organizativa en un transcurrir recursivo, dialógico, complementario y hologramático. El conocimiento que en ella se construye y valida es explicado/comprendido en procesos integradores en la disputa disciplina- multidisciplina- interdisciplina- transdisciplina. Desde lo teórico, se focaliza en perspectivas epistemológicas y educacionales complejas que aportan principios organizadores del pensar superadores de estilos anquilosados, disjuntos y simplificadores. Desde lo empírico, revela lo que piensan y accionan los actores de la comunidad educativa. Se da cuenta de  resultados entretejidos obtenidos a través de métodos, técnicas e instrumentos que responden a una investigación cualitativa -cuantitativa atravesados por la triangulació

Historia y Complejidad. La Historia del Tiempo Presente

El campo historiográfico de la Historia del Tiempo Presente, con su discurso peculiar nos propone una alternativa científica de alta capacidad explicativa para entender las claves de la relación pasado-presente-futuro. El planteo de este artículo busca contribuir en la conceptualización de la historia protagonizada por las generaciones vivas de la Argentina y América Latina, mediante categorías de análisis que consideran los fenómenos de crisis, de incertidumbre de tiempo corto – el acontecimiento-, con una apuesta fuerte por la interdisciplinariedad y por la atención a lo político, valorando la información proporcionada por los testimonios orales, la literatura, la música y el cine que dan cuenta de las sociedades que los produjeron y las nuevas fuentes electrónicas. El paradigma de la complejidad posibilita pensar la historia del tiempo presente concibiendo a la realidad como una dificultad perpetua para ser explicada, abriéndose a un gran número de posibilidades de interpretación

Low-noise monolithic bipolar front-end for silicon drift detectors

Abstract A very low noise, 32-channel preamplifier/shaper chip has been designed for the analogue readout of silicon detectors. The circuit has been optimized in view of the operation of silicon drift detectors, which have very low capacitance and produce gaussian signals of σ of few tens of ns. The chip (OLA) has been designed and manufactured using the SHPi full-custom bipolar process by Tektronix. Each channel is composed by a preamplifier, a shaper and a symmetrical line driver, which allows to drive either a positive and a negative single ended output separately on 50 Ω impedance or a differential twisted pair. The intrinsic peaking time of the circuit is ∼60 ns , and the noise is below 250 electrons at zero input load capacitance. The power consumption is 2 mW/channel, mostly due to the output driver

Esquema de selección de la Raza Caprina Malagueña

Un esquema de selección debe entenderse como un programa de actuaciones que tienen como objetivo último, incrementar la rentabilidad económica de la explotación aumentando los rendimientos productivos o disminuyendo los costes asociados. Ambos objetivos dependen de un conjunto de caracteres que en parte están determinados por factores genéticos y en parte por condicionantes que podrán definirse como del medio ambiente o ambientales

Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum

We report a measurement of low-mass electron pairs observed in 158 GeV/nucleon Pb-Au collisions. The pair yield integrated over the range of invariant masses 0.2 < m < 2.0 GeV is enhanced by a factor of 3.5 +/- 0.4 (stat) +/- 0.9 (syst) over the expectation from neutral meson decays. As observed previously in S-Au collisions, the enhancement is most pronounced in the invariant-mass region 300-700 MeV. For Pb-Au we find evidence for a strong increase of the enhancement with centrality. In addition, we show that the enhancement covers a wide range in transverse momentum, but is largest at the lowest observed pt.Comment: 17 pages, 4 figures, submitted to Phys.Lett.