María José Luque Cubero

Effect of bottlenecking on evolution of the nonstructural protein 3 gene of hepatitis C virus during sexually transmitted acute resolving infection.

ABSTRACT Sexual partners of patients infected with the hepatitis C virus (HCV) often have detectable HCV-specific T-cell responses in the absence of seroconversion, suggesting unapparent, spontaneously resolving infection. To determine whether differences in the evolutionary potential of bottlenecked inoculum may explain the low rate of HCV persistence after sexual exposure, we have investigated changes in the entire HCV nonstructural 3 (NS3) gene over time in a chronic carrier and compared his viral quasispecies with that of the acute-phase isolate of his sexual partner, who developed acute resolving hepatitis C. The overall rate of accumulation of mutations, estimated by regression analysis of six consecutive consensus NS3 sequences over 8 years, was 1.5 × 10−3 mutations per site per year, with small intersample fluctuations related to changes in environmental conditions. Comparison of quasispecies parameters in one isolate of the chronic carrier with those of the acute-phase isolate of the infected partner revealed a higher heterogeneity and lower proportion of nonsynonymous mutations in the former. All NS3 sequences from the acute-phase isolate clustered with a single sequence from the chronic isolate, despite complete HLA mismatch between the patients, suggesting bottlenecking during transmission. The low risk of viral persistence after sexual exposure to HCV may be related to the selection of a limited number of viral particles carrying a particular combination of mutations which may further limit the potential of a relatively homogeneous quasispecies to rapidly diversify and overcome the immune response of the exposed host.

Hepatitis C virus (HCV)-specific T-cell responses among recombinant immunoblot assay-3-indeterminate blood donors: a confirmatory evidence of HCV exposure.

BACKGROUND: Blood donors are routinely screened for hepatitis C virus (HCV) infection. Some show weak anti‐HCV responses, often restricted to a single antigen on confirmatory immunoblot (recombinant immunoblot assay [RIBA]) testing. The aim of this study was to investigate the extent to which such RIBA‐indeterminate donors had previously been exposed to HCV.

Nosocomial transmission of hepatitis C virus during contrast-enhanced computed tomography scanning.

We have investigated two cases of acute hepatitis C that occurred in patients who underwent digestive endoscopy and contrast-enhanced computed tomography (CT) scanning at two different centers. Investigations to identify the sources of infection included an on-site review of diagnostic procedures, interview of the involved healthcare staff, serological testing of the patients who underwent the procedures before and after the index cases and a molecular analysis of viral isolates from the patients and from potential viremic sources. In both cases, the epidemiological investigation identified a chronic hepatitis C virus (HCV) carrier who had been subjected to CT-scanning immediately before the index patient. Genetic distance and molecular phylogenetic analyzes of HCV sequences showed a close relationship between the isolates from these carriers and those from the acute-hepatitis patients, strongly suggesting that patient-to-patient transmission had occurred during CT. This is the first report describing two well documented cases of HCV nosocomial patient-to-patient transmission during contrast-enhanced CT scanning.

Application of Eller's Optical Machine to the Determination of the Molecular Structure of Gases by Electron Diffraction

We present in this paper a new application of the Ellers Optical Machine which allows one to reduce extraordinarily the time of calculations required in the trial and error method. We made the application to the chloride monoxide molecule.

Reversal of nonstructural protein 3‐specific CD4+ T cell dysfunction in patients with persistent hepatitis C virus infection

Summary.  Hepatitis C virus (HCV)‐specific T cell responses are essential for HCV control, and chronic infection is characterized by functionally altered antigen‐specific T cells. It has been proposed that the early inactivation of specific CD4+ T cell responses may be involved in establishment of HCV persistence. We have investigated whether HCV‐specific CD4+ T cells dysfunction can be reversed in vitro. Nonstructural protein 3 (NS3) and core‐specific CD4+ T cells from eight chronically infected and eight spontaneously resolved HCV individuals were selected through transient CD154 (CD40 ligand) expression, and their functional profile (IFN‐γ, IL‐2, TNF‐α, IL‐10 and IL‐4 production by enzyme‐linked immunospot assay, cytometric bead array and intracellular cytokine staining, and proliferation by carboxy‐fluorescein diacetate succinimidyl ester dilution assay) was determined both ex vivo and after in vitro expansion of sorted CD154‐expressing cells in the absence of specific antigen in IL‐7/IL‐15‐supplemented medium. Ex vivo bulk CD4+ T cells from chronic patients expressed CD154 in most cases, albeit at lower frequencies than those of resolved patients (0.11%vs 0.41%; P = 0.01), when stimulated with NS3, but not core, although they had a markedly impaired capacity to produce IL‐2 and IFN‐γ. Antigen‐free in vitro expansion of NS3‐specific CD154+ cells from chronic patients restored IFN‐γ and IL‐2 production and proliferation to levels similar to those of patients with spontaneously resolved infection. Hence, NS3‐specific CD4+ T cell response can be rescued in most chronic HCV patients by in vitro expansion in the absence of HCV‐specific antigen. These results might provide a rationale for adoptive immunotherapy.

New strategies for the treatment of hepatitis C virus infection and implications of resistance to new direct-acting antiviral agents

Persistent hepatitis C virus (HCV) infection is a leading cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma and the major indication for liver transplantation in adults. Current standard of care treatment (SOC) with pegylated-interferon-α 2 and ribavirin (RBV) has a limited efficacy and is associated with significant side effects frequently associated with poor compliance or treatment discontinuation, requiring specialized and frequent monitoring. To overcome the limited efficacy of SOC, more than 50 direct-acting antiviral agents (DAA) designed to target viral-encoded proteins essential in the HCV life cycle are currently under development. The rapid selection of resistant mutants associated with the quasispecies nature of HCV with high mutation and replication rates is one of the main challenges for the new HCV therapies. Predictive host and viral factors together with combination of DAAs with or without IFN and/or RBV need to be accurately evaluated to design the most effective individualized treatment strategy within the shortest time interval and with minimum side effects.

Unit Cell and Space Group of Hg(CN)2.SC(NH2)2

A PRELIMINARY X-ray investigation of the crystal structure of Hg(CN)2.SC(NH2)2 has been made.

Aprendizaje colaborativo en comunidades de práctica en entornos de exclusión social. Un análisis de las interacciones

En este articulo se analizan las interacciones educativas que permiten crear un entorno de colaboracion. El estudio se realiza en una comunidad de practica particular, la Quinta Dimension (5D), un modelo de actividad educativa basado en la cooperacion entre universidad y comunidad, donde se promueve el aprendizaje colaborativo mediado por las TIC. Disenado por el Laboratory of Comparative Human Cognition de la Universidad de California, bajo la direccion de Michael Cole, y fundamentada en la concepcion del enfoque historico cultural del desarrollo humano, se ha adaptado a las culturas locales en diversos paises. En Espana existe una red 5D cuya primera experiencia ha sido la Casa de Shere Rom (CSR), disenada para desarrollar formas de aprendizaje significativo para poblaciones que presentan altos indices de absentismo, abandono y fracaso escolar. La CSR, objeto de analisis en este articulo, es un espacio comunitario en horario extraescolar que atiende a ninos de etnia gitana. Se trata de un proyecto de investigacion-accion participativa, al tiempo que un laboratorio para el desarrollo de nuevas formas de aprendizaje colaborativo que posteriormente se han implementado en horario lectivo en diversas escuelas situadas en entornos con riesgo de exclusion social. Con el fin de analizar los procesos de incorporacion a la comunidad de practicas, las formas de colaboracion para el aprendizaje y la creacion colectiva de una ‘ideocultura’ de significados compartidos, se examinan aqui las interacciones en parejas de ninos y estudiantes universitarios que colaboran para resolver tareas. Mediante un estudio cualitativo, cuyo analisis se ha realizado con el apoyo del programa ATLAS.ti, se pretende responder a las siguientes preguntas: ?Que hacen los participantes para que la interaccion funcione? ?Y para colaborar? ?Que indica que forman parte de esta comunidad? ?Y que indica que tienen un conocimiento compartido del juego o de la tarea concreta?