Université Nantes Angers Le Mans

About: Université Nantes Angers Le Mans is a education organization based out in Nantes, France. It is known for research contribution in the topics: Geology & Finite element method. The organization has 434 authors who have published 249 publications receiving 7208 citations. The organization is also known as: PRES Universite Nantes Angers Le Mans.

Microbiological risk assessments in food industry

Abstract: Microbiological risk assessment (MRA) is a structured process for determining the public health risk associated with biological hazards in a food. It includes hazard identification, exposure assessment, hazard characterization, and risk characterization. Based upon MRA, food safety management is shifting from hazard-based to risk-based management. When performing quantitative MRA (QMRA), mathematical models are used to describe the propagation of microorganisms from the raw materials to the consumer’s plate, the consumption pattern, and subsequent illness. Also, in QMRA, both variability and uncertainty inherent to biological data are taken into account through probability distributions. Estimating quantitatively the risk provides the flexibility of comparing the efficiency of different risk-reduction measures, which could be potentially implemented at the operational level, by predicting their effect on the model output. This chapter is focused on the presentation of these concepts, using as much as possible examples of applications in an industrial context.

Celiprolol induces β3-adrenoceptors-dependent relaxation in isolated porcine coronary arteries

Abstract: In porcine coronary arteries (PCAs), celiprolol, a selective β(1)-adrenoceptors antagonist, induces vasodilatation by an endothelium- and nitric oxide (NO)-dependent pathway. However, the mechanisms of that vascular effect have not been precisely established. β(3)-Adrenoceptors have been shown to be involved in the relaxation per se of various vascular beds, including coronary vessels. Thus, we evaluated (i) the presence of β(3)-adrenoceptors in the PCA and (ii) their role in celiprolol-induced vasodilatation. PCA rings were placed in organ baths and preconstricted with KCl. All experiments were performed in the presence of nadolol (a β(1)/β(2)-adrenoceptor antagonist). Cumulative concentration-response curves to SR 58611A and ICI 215001 (2 β(3)-adrenoceptor agonists) and to celiprolol were constructed. We also used semiquantitative reverse transcription - polymerase chain reaction, which clearly showed the presence of β(3)-adrenoceptor transcripts. SR 58611A, ICI 215001, and celiprolol induced concentration-dependent relaxations in PCA rings. SR 58611A-induced relaxation was almost abolished after removal of endothelium or pretreatment with L-NAME (a NO synthase inhibitor). The vasorelaxations induced by SR 58611A and celiprolol were inhibited in the presence of SR 59230A and L-748337 (2 selective β(3)-adrenoceptor antagonists). We showed (i) that PCAs possess functional β(3)-adrenoceptors mediating endothelium- and NO-dependent relaxation, and (ii) that celiprolol exerts a β(3)-adrenoceptor agonistic activity in this vascular bed.

L’ulcère de Buruli – Un modèle de recherche transversale dynamique au sein du réseau des Instituts Pasteur

Abstract: Buruli ulcer is an endemic severe human skin disease caused by Mycobacterium ulcerans, which prevails in western Africa in swampy areas and primarily hits children. Its gravity comes from the extent of tissue destruction, created by the toxin mycolactone. We describe here how the Centre Pasteur of Cameroon, with the help of the ministry of Health, gathered a network of multidisciplinary partners to fight against Buruli ulcer starting in the years 2000. The Centre Pasteur develops three missions : patient care, training of health care workers and research on the insect vector. Ten years of efforts resulted in significant medical advances such as the design of an early diagnostic test using PCR, or the observation that bed net use significantly decreased the risk of Buruli ulcer, offering useful prevention ; on the research side, entomological studies on aquatic bugs, coupled with epidemiological data, point to the role of these insects in the transmission of the disease. This study examplifies how an efficient network can contribute to the prevention and treatment of debilitating infectious diseases.

Diagnostic différentiel entre récidive tumorale et radionécrose après radiothérapie stéréotaxique d’une métastase cérébrale

Abstract: Resume L’imagerie par resonance magnetique (IRM) est un examen cle dans le suivi des metastases cerebrales irradiees. Certaines prises de contraste suspectes posent le probleme du diagnostic differentiel entre une recidive tumorale et une radionecrose. Les nouvelles techniques multimodales (perfusion et spectrometrie) et la tomographie par emission de positons (TEP) permettent d’affiner le diagnostic et se posent en alternative d’un prelevement histologique par biopsie stereotaxique, seule methode fiable, mais invasive. Nous rapportons ici le cas d’une patiente atteinte d’une metastase frontale gauche d’un carcinome mammaire sept mois apres la prise en charge chirurgicale, suivie d’une radiotherapie stereotaxique du lit operatoire. L’IRM en zone irradiee a constate une prise de contraste suspecte pour laquelle la distinction entre recidive tumorale et radionecrose n’a pas pu etre determinee sur les sequences de perfusion. La realisation d’une TEP au ( 18 F)-fluorodesoxyglucose (FDG) a permis de mettre en evidence une lesion hypermetabolique. Apres exerese chirurgicale, l’analyse histologique retrouvait principalement de la radionecrose associee a la presence de cellules carcinomateuses. Malgre l’IRM multimodale, la distinction entre une recidive tumorale et une radionecrose reste souvent difficile. La TEP-FDG est une aide diagnostique, en faveur de la recidive, en cas de lesion hypermetabolique. D’autres traceurs (fluores ou marques au carbone 11) sont interessants mais ne sont pas disponibles dans tous les centres. La biopsie stereotaxique reste a discuter si le doute persiste, avec un changement d’attitude therapeutique a la cle.