Mechanisms of protective immunity against asexual blood stages of Plasmodium falciparum in the experimental host Saimiri

In the Saimiri monkey, an experimental host for human malaria, acquired protection against Plasmodium falciparum blood stages depends on the IgG antibody populations developed. In vivo protective anti-falciparum activity of IgG antibodies is correlated with the in vivo opsonizing activity promoting phagocytosis of parasited red bloood cells. In contrast, non protective antibodies inhibit this mechanism by competing at the target level. A similar phenomenon can be and human infection. Anti-cytoadherent and anti-rosette antibodies developed by Saimiri and humans prevent the development of physiopathological events like cerebral malaria which can also occur in this experimental host. Furthermore, transfer to protective human anti-falciparum IgG antibodies into infected Saimiri monkeys exerts an anti parasite activity as efficient as that observed when it is transfered into acute falciparum malaria patients, making the Saimiri an even more attractive host. Studies on the role of immunocompetent cells in the protective immune reponse are still in their infancy, however the existance of a restricted polymorphism of MHC II class molecules in the Saimiri confers additional theoretical and practical importance to this model.

Trypanosoma cruzi recognition by macrophages and muscle cells: perspectives after a 15-year study

Macrophages and muscle cells are the main targets for invasion of Trypanosoma cruzi. Ultrastructural studies of this phenomenon in vitro showed that invasion occurs by endocytosis, with attachment and internalization being mediated by different components capable of recognizing epi-or trypomastigotes (TRY). A parasitophorus vacuole was formed in both cell types, thereafter fusing with lysosomes. Then, the mechanism of T. cruzi invasion of host cells (HC) is essentially similar (during a primary infection in the abscence of a specific immune response), regardless of wether the target cell is a professional or a non-professional phagocytic cell. Using sugars, lectins, glycosidases, proteinases and proteinase inhibitors, we observed that the relative balance between exposed sialic acid and galactose/N-acetyl galactosamine (GAL) residues on the TRY surface, determines the parasite's capacity to invade HC, and that lectin-mediated phagocytosis with GAL specificity is important for internalization of T. cruzi into macrophages. On the other hand, GAL on the surface to heart muscle cells participate on TRY adhesion. TRY need to process proteolytically both the HC and their own surface, to expose the necessary ligands and receptors that allow binding to, and internalization in the host cell. The diverse range of molecular mechanisms which the parasite could use to invade the host cell may correspond to differences in the available "receptors"on the surface of each specific cell type. Acute phase components, with lectin or proteinase inhibitory activities (a-macroglobulins), may also be involved in T. cruzi-host cell interaction.

Is the thymus a target organ in infectious diseases?

The thymus is a central lymphoid organ, in wich T cell precursors differentiale and generate most of the so-called T cell reprtoire. Along with a variety of acute infectious diseases, we and others determined important changes in both microenvironmental and lymphoid compartments of the organ. For example, one major and common feature observed in acute viral, bacterial and parasitic diseases, is a depletion of cortical thymocytes, mostly those bearing the CD4-CD8 double positive phenotype. This occurs simmultaneously to the relative enrichment in medullary CD4 or CD8 single positive cells, expressing high densities of the CD3 complex. Additionally we noticed a variety of changes in the thymic microenvironment (and particularly is epithelial component), comprising abnormal location of thymic epithelial cell subsets as well has a denser Ia-bearing cellular network. Moreover, the extracellular matrix network was altered with an intralobular increase of basement membrane proteins that positively correlated with the degree of thymocyte death. Lastly, anti-thymic cell antibodies were detected in both human and animal models of infectious diseases, and in some of them a phenomenon of molecular mimicry could be evidenced. Taken together, the data receiwed herein clearly show that the thymus should be regarded as a target in infectious diseases.

Evaluation of virulence factors in environmental isolates of Vibrio species

Strains of Vibrio parahaemolyticus, Vibrio fluvialis and Vibrio mimicus isolated from seafood and seawater were examined for characteristics related to infectivity, such as enzymatic activity and animal assays. All strains hydrolysed DNA, starch, gelatin and chitin. Variable results were obtained with the haemolysin, chondroitin, collagen, elastin and lecithin tests. Production of thermostable direct haemolysin by V. parahaemolyticus was detected in 7.1% strains derived from seafood and 2%from seawater. In the animal assays, strains of V. fluvialis showed positive results at skin PF (75%), mouse lethality (100%), but no fluid accumulation in the suckling mice model was noted. Concerning V. mimicus, results showed skin PF (100%), mouse lethality (100%) and fluid accumulation in suckling mice (66.6%).

Vulnerability to poverty: A microeconometric approach and application to the Republic of Haiti

This paper investigates vulnerability to poverty in Haiti. Research in vulnerability in developing countries has been scarce due to the high data requirements of vulnerability studies (e.g. panel or long series of cross-sections). The methodology adopted here allows the assessment of vulnerability to poverty by exploiting the short panel structure of nested data at different levels. The decomposition method reveals that vulnerability in Haiti is largely a rural phenomenon and that schooling correlates negatively with vulnerability. Most importantly, among the different shocks affecting household's income, it is found that meso-level shocks are in general far more important than covariate shocks. This finding points to some interesting policy implications in decentralizing policies to alleviate vulnerability to poverty.

Prophytaxie de l'ostéoporose cortisonique: qui, quand et quoi [Prevention of cortisone-induced osteoporosis: who, when and what?]

Glucocorticoid-induced osteoporosis is a known phenomenon with already an increased fracture risk at 2.5 mg of prednisone daily over 3 months. This risk appears to be independent of bone densitometry results, in contradiction with published guidelines. With the creation of our Department of Musculoskeletal Medicine, we wanted to edict clear recommendations for the prevention of steroid-induced osteoporosis. In addition to the standard general measures to prevent osteoporosis and calcium and vitamin D supplementation, we advocate the use of a specific treatment for osteoporosis in all cases when the duration of corticosteroid therapy is not strictly limited and shorter than 3 months. Bisphosphonates are the treatment of choice, while the analogue of parathyroid hormone remains an alternative in cases with a very high fracture risk.

Mujeres inmigradas y prácticas sociolegales en situaciones de violencia en la pareja: diferencias, desigualdades y disidencias en los contextos de atención

La investigación aborda el problema de la violencia de género dentro de la pareja en mujeres inmigrantes. El objetivo es conocer el impacto de los dispositivos sociolegales sobre las propias mujeres inmigrantes, a la vez que se conoce como el fenómeno de la inmigración ha influido en las prácticas institucionales. Los resultados indican efectos de protección y a la vez efectos perversos en los dispositivos sociolegales que se cuidan de las mujeres inmigradas. Se hacen propuestas para una intervención más situada y reflexiva.

Anti-embryonation immunity in murine schistosomiasis japonica (Philippines)

The hypothesis that granuloma modulation and disease abatement in chronic infection with Schistosoma japonicum could be ascribed to antibody-mediated effects on egg maturation and egg viability, arose from studies performed with mice in the Philippines. This novel hypothesis has not yet been integrated into the schistosomiasis literature despite being formulated more than a decade ago. One reason for this is that the phenomenon might be confined to S. japonicum, even S. japonicum (Philippines).

A one-year monitoring of nicotine use in sport: frontier between potential performance enhancement and addiction issues.

Tobacco consumption is a global epidemic responsible for a vast burden of disease. With pharmacological properties sought-after by consumers and responsible for addiction issues, nicotine is the main reason of this phenomenon. Accordingly, smokeless tobacco products are of growing popularity in sport owing to potential performance enhancing properties and absence of adverse effects on the respiratory system. Nevertheless, nicotine does not appear on the 2011 World Anti-Doping Agency (WADA) Prohibited List or Monitoring Program by lack of a comprehensive large-scale prevalence survey. Thus, this work describes a one-year monitoring study on urine specimens from professional athletes of different disciplines covering 2010 and 2011. A method for the detection and quantification of nicotine, its major metabolites (cotinine, trans-3-hydroxycotinine, nicotine-N'-oxide and cotinine-N-oxide) and minor tobacco alkaloids (anabasine, anatabine and nornicotine) was developed, relying on ultra-high pressure liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-TQ-MS/MS). A simple and fast dilute-and-shoot sample treatment was performed, followed by hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS) operated in positive electrospray ionization (ESI) mode with multiple reaction monitoring (MRM) data acquisition. After method validation, assessing the prevalence of nicotine consumption in sport involved analysis of 2185 urine samples, accounting for 43 different sports. Concentrations distribution of major nicotine metabolites, minor nicotine metabolites and tobacco alkaloids ranged from 10 (LLOQ) to 32,223, 6670 and 538 ng/mL, respectively. Compounds of interest were detected in trace levels in 23.0% of urine specimens, with concentration levels corresponding to an exposure within the last three days for 18.3% of samples. Likewise, hypothesizing conservative concentration limits for active nicotine consumption prior and/or during sport practice (50 ng/mL for nicotine, cotinine and trans-3-hydroxycotinine and 25 ng/mL for nicotine-N'-oxide, cotinine-N-oxide, anabasine, anatabine and nornicotine) revealed a prevalence of 15.3% amongst athletes. While this number may appear lower than the worldwide smoking prevalence of around 25%, focusing the study on selected sports highlighted more alarming findings. Indeed, active nicotine consumption in ice hockey, skiing, biathlon, bobsleigh, skating, football, basketball, volleyball, rugby, American football, wrestling and gymnastics was found to range between 19.0 and 55.6%. Therefore, considering the adverse effects of smoking on the respiratory tract and numerous health threats detrimental to sport practice at top level, likelihood of smokeless tobacco consumption for performance enhancement is greatly supported.

In the name of democracy: Disobedience and value-oriented citizenship

Recently, some scholars have highlighted a paradoxical phenomenon existing in democratic systems:Those people who show the greatest support for democracy are also those most willing to protestagainst the authority and to question it. However, if we consider the tasks of contemporary democraticcitizenship in a social-psychological perspective, this apparent paradox becomes understandable.Obedience to authority may ensure the continuity of social and group life, but disobedience may becrucial in stopping the authority relationship from degenerating into an authoritarian one. FollowingKelman and Hamilton's analysis of legitimacy dynamics, we consider how actions of disobediencemay serve the defence of democracy. In particular, by considering the different ways in which peoplerelate to the political system, the relevance of so-called value-oriented citizens in supportingdemocracy will be considered.

"Periodic crises": Clément Juglar between theories of crises and theories of business cycles

Business cycle theory is normally described as having evolved out of a previous tradition of writers focusing exclusively on crises. In this account, the turning point is seen as residing in Clément Juglar's contribution on commercial crises and their periodicity. It is well known that the champion of this view is Schumpeter, who propagated it on several occasions. The same author, however, pointed to a number of other writers who, before and at the same time as Juglar, stressed one or another of the aspects for which Juglar is credited primacy, including the recognition of periodicity and the identification of endogenous elements enabling the recognition of crises as a self-generating phenomenon. There is indeed a vast literature, both primary and secondary, relating to the debates on crises and fluctuations around the middle of the nineteenth century, from which it is apparent that Juglar's book Des Crises Commerciales et de leur Retour Périodique en France, en Angleterre et aux États-Unis (originally published in 1862 and very much revised and enlarged in 1889) did not come out of the blue but was one of the products of an intellectual climate inducing the thinking of crises not as unrelated events but as part of a more complex phenomenon consisting of recurring crises related to the development of the commercial world - an interpretation corroborated by the almost regular occurrence of crises at about 10-year intervals.

Living in the Wrong Neighbourhood: State Failure and its Implications for Neighbouring Countries

Why and how do failed states affect neighbouring countries? The attention of the international community towards state failure has grown significantly in recent years, improving the understanding of this phenomenon; nevertheless, the knowledge about the influence of state failure on neighbouring countries remain scarce. This research aims at contributing to filling up the existing gap by analyzing two different cases of state failure –Liberia and Afghanistan– and its consequences on four of their neighbours –Sierra Leone, Guinea, Pakistan and Tajikistan. More concretely, this research investigates the importance of insurgency movements in the relationship between these countries. The research argues that failed states generate conflict-enhancing mechanisms –which might lead to conflict outbreak– in their neighbours through the creation of informal networks. The empiric evidence shows how insurgency-based informal networks have a decisive role in the outbreak of conflict.

Paraphrasing : scope and typology : a computational approach

This PhD project aims to study paraphrasing, initially understood as the different ways in which the same content is expressed linguistically. We will go into that concept in depth trying to define and delimit its scope more accurately. In that sense, we also aim to discover which kind of structures and phenomena it covers. Although there exist some paraphrasing typologies, the great majority of them only apply to English, and focus on lexical and syntactic transformations. Our intention is to go further into this subject and propose a paraphrasing typology for Spanish and Catalan combining lexical, syntactic, semantic and pragmatic knowledge. We apply a bottom-up methodology trying to collect evidence of this phenomenon from the data. For this purpose, we are initially using the Spanish Wikipedia as our corpus. The internal structure of this encyclopedia makes it a good resource for extracting paraphrasing examples for our investigation. This empirical approach will be complemented with the use of linguistic knowledge, and by comparing and contrasting our results to previously proposed paraphrasing typologies in order to enlarge the possible paraphrasing forms found in our corpus. The fact that the same content can be expressed in many different ways presents a major challenge for Natural Language Processing (NLP) applications. Thus, research on paraphrasing has recently been attracting increasing attention in the fields of NLP and Computational Linguistics. The results obtained in this investigation would be of great interest in many of these applications.

Recrudescence induced by cyclophosphamide of chronic Trypanosoma cruzi infection in mice is influenced by the parasite strain

Reactivation of chronic chagasic patients may occur upon use of immunosuppressive drugs related to kidney or heart transplantation or when they are affected by concomitant HIV infection. This recrudescence, however, does not occur in all chagasic patients exposed to immunosuppressive agents. We therefore investigated the influence of Trypanosoma cruzi strains in the recrudescence of the parasitism in mice at the chronic phase treated with cyclophosphamide, an immunosuppressor that blocks lymphocytes DNA synthesis and therefore controls B cells response. A large variation was detected in the percentages of newly established acute phases in the groups of mice inoculated with the different strains. We suggest that reactivation of chronic T. cruzi infections is influenced by the parasite intrinsic characteristics, a phenomenon that might occur in the human disease.

Trypanosoma cruzi infection in offspring born to chagasic C3H/He mice

This study reports the effects of Trypanosoma cruzi infection induced in C3H/He male and female mice born to chagasic mice. An experimental model was established infecting female C3H/He mice with a low virulent T. cruzi clone. In this model, mating, fertilization, pregnancy evolution and delivery was carried out successfully. The offspring was infected at four, six and eigth weeks of age. The results showed that the offspring born to chagasic mothers present decreased resistance to acquired T. cruzi infection. This decreased resistance was expressed by higher levels of parasitaemia and higher mortality rates in offspring born to chagasic mothers than in controls. Age and sex were shown to be important factors of this phenomenon. The results suggest that maternal immune system products can modulate the immune response of the offspring.