Sérotypes de Salmonella isolés chez les petits ruminants abattus à Dakar

Une enquête sur le portage chronique de Salmonella chez les petits ruminants sacrifiés à l'abattoir de Dakar est effectuée. Les ganglions mésentériques de 1 108 ovins et 1 018 caprins sont recueillis. Après enrichissement en milieu sélénite, 90 souches sont isolées appartenant à 52 sérotypes. 2 sérotypes nouveaux sont découverts: S. derklé et S. lodé et 3 sérotypes rapportés pour la première fois au Sénégal: S. lawra, S. ruiru et S. tornow. Le taux d'infection chez le mouton s'établit à 4,7 p. 100 et chez la chèvre à 3,6 p. 100. Ces résultats sont voisins de ceux obtenus dans d'autres pays africains. L'incidence sur l'hygiène publique du portage chronique de Salmonella chez les petits ruminants est discuté

Portage de Salmonella chez Testudo sulcata, tortue terrestre du Sénégal

Une enquête épidémiologique est effectuée sur le portage chronique de Salmonella chez une tortue africaine Testudo sulcata. 30 prélèvements d'excréments ont permis de mettre en évidence 6 sérotypes: S. oranienburg, S. corvallis, S. durban, S. ilandoff, S. bahrenfeld, S. adelaïde. S. bahrenfeld est isolé pour la première fois au Sénégal. Les possibilités de contamination de l'homme et d'espèces animales domestiques sont envisagée

Juicios heurísticos sobre probabilidad en alumnos del profesorado en matemática

En el presente trabajo se analizó la presencia de razonamientos heurísticos en alumnas del Profesorado en Matemática que ya habían cursado la asignatura “Probabilidad y Estadística” y que asistieron a un taller sobre enseñanza de la probabilidad. Los problemas utilizados son ítems de investigación citados por Shaughnessy (1992). Se detectaron razonamientos inapropiados en los problemas relacionados con el descuido del tamaño de muestra, la falacia de la proporción baja y el error de atribución fundamental. Además se percibieron dificultades de argumentación en las respuestas brindadas. A partir de una exploración acerca de las respuestas obtenidas en este grupo reducido de alumnas se intentó formular líneas de investigación a futuro sobre posibles implicancias en los planes de formación

An ex-vivo Human Intestinal Model to Study Entamoeba histolytica Pathogenesis

Amoebiasis (a human intestinal infection affecting 50 million people every year) is caused by the protozoan parasite Entamoeba histolytica. To study the molecular mechanisms underlying human colon invasion by E. histolytica, we have set up an ex vivo human colon model to study the early steps in amoebiasis. Using scanning electron microscopy and histological analyses, we have established that E. histolytica caused the removal of the protective mucus coat during the first two hours of incubation, detached the enterocytes, and then penetrated into the lamina propria by following the crypts of Lieberkühn. Significant cell lysis (determined by the release of lactodehydrogenase) and inflammation (marked by the secretion of pro-inflammatory molecules such as interleukin 1 beta, interferon gamma, interleukin 6, interleukin 8 and tumour necrosis factor) were detected after four hours of incubation. Entamoeba dispar (a closely related non-pathogenic amoeba that also colonizes the human colon) was unable to invade colonic mucosa, lyse cells or induce an inflammatory response. We also examined the behaviour of trophozoites in which genes coding for known virulent factors (such as amoebapores, the Gal/GalNAc lectin and the cysteine protease 5 (CP-A5), which have major roles in cell death, adhesion (to target cells or mucus) and mucus degradation, respectively) were silenced, together with the corresponding tissue responses. Our data revealed that the signalling via the heavy chain Hgl2 or via the light chain Lgl1 of the Gal/GalNAc lectin is not essential to penetrate the human colonic mucosa. In addition, our study demonstrates that E. histolytica silenced for CP-A5 does not penetrate the colonic lamina propria and does not induce the host's pro-inflammatory cytokine secretion

On-site screening of farming-induced chronic obstructive pulmonary disease with the use of an electronic mini-spirometer: results of a pilot study in Brittany, France.

International audiencePURPOSE: Dairy farming is a risk factor for the development of chronic obstructive pulmonary disease (COPD). We assessed the prevalence of farming-induced COPD (FI-COPD) using a new screening device, and we analyzed symptoms and occupational risk factors. METHODS: We performed on-site screening study of bronchial obstruction using an electronic mini-spirometer (EMS) on an entire population of dairy farmers (n = 147) from two villages in Brittany, France. Suspected bronchial obstruction (FEV1/FEV6 <0.8) was confirmed with standardized lung function tests (FEV1/FVC ≤0.7). We assessed past medical histories, respiratory symptoms, and occupational tasks of subjects with bronchial obstruction; asthmatics were defined as atopic and/or reversible; smoking-induced COPD patients were defined as non-reversible, non-atopic with smoking histories (≥5 PY); and FI-COPD patients were defined as non-reversible, non-atopic, and non-smokers. RESULTS: Using the EMS, 30.6% (n = 45) of dairy farmers were suspected of bronchial obstruction and underwent standardized spirometry. The FEV1/FEV6 ratio and FEV1/FVC ratio were in good agreement (r² = 0.66, P < 0.0001). The prevalence of confirmed bronchial obstruction was 9.5% (n = 14), which included 4 asthmatics, 3 smoking-induced COPD subjects, and 7 FI-COPD subjects. All the COPD patients were GOLD Stage II, and none were aware of their respiratory disease. Foddering duration was significantly higher in FI-COPD subjects compared with non-obstructive subjects, with 44 versus 17 min/day, respectively. CONCLUSIONS: The EMS was a convenient mean of screening for bronchial obstruction, especially in on-site settings, and allowed us to diagnose FI-COPD in a non-spontaneously complaining dairy farmer population. Foddering was considered a significant risk factor

Oil extraction kinetics of hydrothermally pretreated canola seeds

In this work the kinetics of oil extraction from spring canola seeds subjected to a hydrothermal pretreatment with direct steam (393 K, 5 min) was studied. The differences between the seed internal structure generated by the application of this pretreatment and that of the untreated sample (ground sample) were observed by scanning electron microscopy. Oil from both samples was extracted with hexane at different times and temperatures using a stirred batch system. Oil yield increased up to 46 % due to the hydrothermal treatment. A model was proposed to explain the oil extraction process from hydrothermally pretreated and untreated canola seeds, taking into account two main mechanisms: a washing process of the surface oil from the seed, and a diffusion process. Parameters of the model were fitted, and values of the oil fraction extracted during the washing step (0.27 and 0.50 for untreated and hydrothermally treated canola seeds, respectively) and the effective diffusion coefficient (3.1–9.4.10- 12 m2 s 1 ) were obtained. The latter value showed an Arrhenius-type temperature dependence in the untreated sample, but the diffusion coefficient did not vary with temperature when oil diffusion was analyzed using hydrothermally pretreated seeds.Fil: Zárate, Valeria. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Grupo Tecnologias de Semillas; ArgentinaFil: Perez, Ethel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Crapiste, Guillermo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Nolasco, Susana M.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Grupo Tecnologias de Semillas; ArgentinaFil: Fernández, María Belén. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Grupo Tecnologias de Semillas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin