Effects of environmental Bisphenol A exposures on germ cell development and Leydig cell function in the human fetal testis

<div><p>Background</p><p>Using an organotypic culture system termed human Fetal Testis Assay (hFeTA) we previously showed that 0.01 μM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models.</p><p>Methods</p><p>Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 μM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 μM BPA (~ 500 μg/kg/day) in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 μM and 0.038 μM respectively. Mice grafted with second trimester testes received 0.5 and 50 μg/kg/day BPA by oral gavage for 5 weeks.</p><p>Results</p><p>With first trimester human testes, using the hFeTA model, 10 μM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice.</p><p>Conclusions</p><p>Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.</p></div

Être catéchiste : témoigner d’une expérience. Enquêtes auprès des catéchistes en Belgique (Vicariats de Bruxelles et du Brabant wallon) et en France (Diocèses de Nanterre et Créteil)

La première partie de l’ouvrage rend compte des résultats de l’enquête belge menée par le Centre universitaire de théologie pratique (UCL) auprès de personnes engagées en catéchèse dans la partie francophone du diocèse de Malines-Bruxelles entre novembre 2012 et janvier 2013. Il est rendu compte des constats qui se dégagent de 337 réponses reçues et des résultats de l’analyse statistique des données récoltées. La deuxième partie de l’ouvrage présente les résultats de l’enquête française, fruit d'un travail réalisé au cours de l'année universitaire 2013-2014 à l'Institut Supérieur de Pastorale Catéchétique (ICP) dans les diocèses de de Créteil et de Nanterre. 44 personnes ont été rencontrées. Les entretiens ont fait l'objet d'un double dépouillement : l'un à partir de relectures collectives pour repérer comment se construisait une identité de catéchistes, l'autre par informatique. La troisième partie de l’ouvrage s’arrête aux convergences qui se dégagent des deux enquêtes, en particulier en ce qui concerne le rapport entre expérience et doctrine, la relation aux enfants, aux parents, à l’institution ecclésiale et le rapport des catéchistes à leur expérience catéchétique

Tsunami deposits in Santiago Island (Cape Verde archipelago) as possible evidence of a massive flank failure of Fogos volcano

International audienc

Chez les spiroplasmes le codon UGA n'est pas non sens et semble coder pour le tryptophane

National audienc

Interactive Learning of Nanophysics Phenomena

This paper describes a new method of teaching and experimenting nanophysics effects using a nanomnipulator. This nano-manipulator is formed by a multi-sensory platform connected to an AFM and/or to virtual nano-scenes produced by a real-time simulator. The first objective of this work is the evaluation of a custom-made nanomanipulator compared to the use of a classical Atomic Force Microscope (AFM) interface. These instruments are used to teach one-dimensional nano-physical phenomenon, the approach-retract (AR) one, to university students at master level. The second objective is to determine the role of each sensorial rendering (force, visual and sound) and their combination, in the understanding process of the AR phenomenon. These two objectives have been evaluated quantitatively and qualitatively by analysing student practical work reports

Educational Tool for Nanophysics Using Multisensory Rendering

The presentation and the evaluation of an educational tool used to teach physical phenomena that take place at a nanometer scale are the central objectives of the work presented in this paper. Through concepts and tools, the real phenomena are connected to the virtual world, which furnish sensorial representations (haptic, visual, auditory) for the student who is experimenting. A computer representation of the nanoscene at the atomic level offers a multisensory tangible artifact of nanoworld inaccessible entities. The parameters accessibility allows students to design by themselves and perceive various contact interactions, to understand the origins of complex phenomena as the approach-retract nano-palpating effect. An interactive way for teaching and understanding the differences between the nanoscale physics and the macroscale physics is illustrated through an experience when students shake the Drosophilae leg. Real nanomanipulations on various samples by means of the developed multisensorial platform confirm better results in student comprehension and dexterity for achieving the same item as with the classical tools

Left atrial remodelling assessed by 2D and 3D echocardiography identifies paroxysmal atrial fibrillation

Aims Paroxysmal atrial fibrillation (PAF) is common, often silent, and can be difficult to detect. Echocardiographic parameters assessing left atrial (LA) remodelling correlated with atrial fibrosis in permanent AF, but less is known about earlier stages such as PAF. We aimed to evaluate whether 2D and 3D echocardiographic (2DE and 3DE) assessment of LA anatomy and function is able to identify patients with PAF.Methods and results This case control study included 102 patients without overt heart disease, 44 patients with PAF. Anatomical remodelling was assessed using indexed maximal, minimal, and preatrial contraction volumes. Reservoir, conduit, and pump functions were assessed by volume and strain methods. All parameters were assessed by 2DE and 3DE and were compared between the two groups. Receiver-operating characteristic curves were constructed for each parameter for PAF prediction. PAF patients had bigger LA volumes than non-PAF group. Using 3DE, all atrial functions were impaired in the PAF group, regardless of the parameters used (all P < 0.05), whereas using 2DE, conduit function did not reach significant difference. Areas under the curve (AUCs) for 3D parameters were higher than those for equivalent 2DE parameters. PAF was best predicted by LA minimal indexed volume assessed by 2DE or 3DE (AUC 0.82 and 0.86, respectively) and 3D-LA ejection fraction and area strain (AUC = 0.82 and 0.81, respectively).Conclusion Anatomical and functional LA remodelling assessed by 2DE and 3DE is independently and strongly associated with PAF, suggesting that these parameters can help identify PAF

Antimicrobial peptides in oyster hemolymph: the bacterial connection.

International audienceWe have explored antimicrobial compounds in oyster hemolymph and purified four active peptides with molecular masses of 4464, 3158, 655 and 636 Da. While no exploitable structural elements were obtained for the former three, a partial amino acid sequence (X-P-P-X-X-I-V) was obtained for the latter, named Cg-636. Due to both its low MM and the presence of exotic amino acid residue (X), we suspected a bacterial origin and tracked cultivable hemolymph-resident bacteria of oyster for their antimicrobial abilities. Supernatants of 224 hemolymph resident bacteria coming from 60 oysters were screened against 10 target bacteria including aquaculture pathogens. Around 2% (5 strains) revealed antimicrobial activities. They belong to Pseudoalteromonas and Vibrio genera. Two closely related strains named hCg-6 and hCg-42 have been shown to produce Bacteriocin-Like Inhibitory Substances (BLIS) even in oyster hemolymph. We report herein first BLIS-producing bacteria isolated from bivalve hemolymph. These results strongly suggest that hemolymph resident bacteria may prevent pathogen establishment and pave the way for considering a role of resident bacteria into bivalve defense

La formation d’ingénieurs en alternance

Le rythme et la progressivité de la formation sont souvent en cause lorsque l'on met en œuvre des contrats d'apprentissage. La conception et l’appropriation de ces rythmes intéressent tous les acteurs des formations d’ingénieurs en alternance (responsables, tuteurs, apprentis). L’état de la recherche sur cette question centrale évolue. Nous en rendons compte ici à travers des textes de réflexion, une mise en perspective historique et des témoignages de cas pratiques, comme celui de la formation dispensée par le CFA Ingénieurs 2000. Apparaissent alors dans la construction et la mise en œuvre des formations professionnelles les nuances entre temporalité prescrite, ressentie et vécue.Work-based engineering training articulates two main contexts (firms and universities), and specifically an agenda with time of production and time of formation. This bookinvestigates time lived by trainee engineers and their engineering tutors in this work-based training contexts