Étude de la négativité de discordance dans l'amusie congénitale

L’amusie congénitale est un trouble neuro-développemental qui s’exprime par un déficit de discrimination tonale fine. Le cerveau des amusiques ne répond pas aux petites différences de hauteur, tel que révélé par l’absence de la composante de potentiel évoqué P3b, qui est associée aux processus de discrimination tonale tardifs et conscients. Peu d’études se sont penchées sur les mécanismes précoces et préconscients de discrimination tonale chez les amusiques, qui peuvent être étudiés par l’entremise d’une composante de potentiel évoqué appelée la négativité de discordance (MMN). Certaines études ont démontré qu’il est possible d’enregistrer la MMN pendant la présentation d’un film avec la trame sonore en simultané aux sons visant à évoquer la composante. Toutefois, une étude a démontré que la présentation de la trame sonore réduisait l’amplitude de la MMN, sans néanmoins clarifier la nature de l’effet d’interférence en cause. Les objectifs du présent projet sont d’abord, d’investiguer les effets à l’origine de la réduction d’amplitude de la MMN observée lors de la présentation d’un film avec la trame sonore, puis d’évaluer cette même composante chez les amusiques. La première étude visait à déterminer si un effet d’interférence attentionnelle ou acoustique était en cause dans la réduction d’amplitude observée sur la MMN lors de la présentation de la trame sonore d’un film. Les résultats ont montré qu’un effet de masquage acoustique, attribuable à la trame sonore, était responsable de la réduction d’amplitude de la MMN, cette dernière augmentant au fur et à mesure que l’intensité sonore de la trame du film était réduite. La seconde étude a été conduite dans le but d’investiguer la MMN chez les amusiques et de vérifier si le complexe d’ondes anormales N2b-P3b, observé en réponse aux grandes différences tonales chez les amusiques, pouvait être attribuable à un effet de saillance des stimuli. Dans un premier temps, nous avons comparé la MMN des amusiques à celle des contrôles, puis nous avons modifié le paradigme expérimental visant à évoquer la N2b-P3b en ajustant les probabilités d’occurrence des sons présentés aux contrôles en fonction des sons perçus par les amusiques. Les résultats ont montré que le cerveau des amusiques parvient à discriminer les différences de hauteur à un niveau précoce et préconscient, tel que révélé par une MMN normale, mais que les réponses cérébrales plus tardives, associées au processus de discrimination des hauteurs conscient, sont anormales chez les amusiques, et ce, uniquement pour les petites différences de hauteur, tel que révélé par l’absence de la P3b. En conclusion, ces résultats démontrent que l’amplitude de la MMN est affectée de manière significative par la présentation de la trame sonore d’un film et que cela est attribuable à un effet d’interférence acoustique. Dans un deuxième temps, nous avons démontré que les mécanismes précoces et préconscients de discrimination tonale sont préservés chez les amusiques, et que le déficit sous-jacent à l’amusie congénitale est attribuable à une atteinte du processus de discrimination tonale fine associé à un niveau de traitement cérébral tardif et conscient, le complexe d’ondes anormales N2b-P3b étant pour sa part attribuable à un effet de saillance des stimuli.Congenital amusia is a neurodevelopmental disorder which is characterized by a deficit in fine-grained pitch discrimination. In fact, the amusic brain does not respond to small pitch changes, such as reflected by the absence of the event-related (ERP) component P3b, which is associated to late and conscious pitch discrimination processes. Until now, very few studies focused on early preconscious levels of processing in amusia, which can be studied through an ERP component called the mismatch negativity (MMN). Some studies have demonstrated that the MMN can be recorded while playing the soundtrack of a movie in concurrence with the MMN-critical tones. However, one study demonstrated that playing the movie soundtrack reduced MMN amplitude, but did not investigate the origin of this effect. The main goals of this project are, first, to investigate the nature of the effect responsible for the MMN reduction observed when playing a movie soundtrack, and secondly, to evaluate the MMN in congenital amusia. The first study aimed to investigate if an attentionnal or acoustical interference effect could account for the reduction in MMN amplitude observed when playing the movie soundtrack. The results showed that an acoustical masking effect of the movie soundtrack was responsible for the reduction in MMN amplitude. In fact, MMN amplitude increased as the intensity level of the movie soundtrack decreased. The goal of the second study was to investigate the MMN in congenital amusia, but also to explore if the abnormal N2b-P3b complex observed in amusics in a previous study could be accounted for by an effect of salience of the stimuli. Thus, we first compared the MMN results between amusics and controls, and then, we modified the experimental paradigm meant to evoke the N2b-P3b by adjusting the probabilities of occurrence of the sounds presented to the controls as a function of the sounds perceived by their matched amusics. The results showed that the amusic brain can detect all pitch changes at an early and preconscious level of processing, such as demonstrated by a normal MMN in both groups. Furthermore, our results showed that the amusic brain does not respond normally solely to small pitch changes at a later conscious level of processing, such as revealed by the absence of the P3b, thus showing that the abnormal N2b-P3b complex of ERP components observed in a previous study is better explained by a saliency effect of the stimuli and does not represent an electrophysiological anomaly specific to congenital amusia. In conclusion, our results have first shown that MMN amplitude is decreased by presenting a movie soundtrack and this is due to a masking effect at the acoustical level of the soundtrack over the MMN-critical tones. Finally, our second study showed that the early preconscious mechanisms of pitch discrimination are preserved in congenital amusia, and that the pitch deficit underlying congenital amusia is limited to an anomaly in the late and conscious processing of small pitch changes, the abnormal N2b-P3b complex being rather explained by an effect of salience of the stimuli

A License-Based Search Engine

International audienceThe reuse of licensed resources to produce new ones is very common and encouraged on the Web. But producing resources whose licenses are compliant with all reused resource licenses is not easy. It is necessary to know (1) the set of licenses with which the license of the produced resource is compliant and (2) what are the available resources whose licenses are part of this set. With CaLi, we provide an answer to the first concern. CaLi is a lattice-based model that partially orders licenses in terms of compatibility and compliance. In this demonstration, we illustrate the usability of CaLi through a prototype for the second concern. That is, based on a CaLi ordering of licenses we implement a license-based search engine which can answer questions such as "find licensed resources that can be reused under a given license" or "find licensed resources that can reuse a resource that has a particular license"

Impact of cleaning and disinfection procedures on microbial ecology and Salmonella antimicrobial resistance in a pig slaughterhouse

International audienceTo guarantee food safety, a better deciphering of ecology and adaptation strategies of bacterial pathogens such as Salmonella in food environments is crucial. The role of food processing conditions such as cleaning and disinfection procedures on antimicrobial resistance emergence should especially be investigated. In this work, the prevalence and antimicrobial resistance of Salmonella and the microbial ecology of associated surfaces communities were investigated in a pig slaughterhouse before and after cleaning and disinfection procedures. Salmonella were detected in 67% of samples and isolates characterization revealed the presence of 15 PFGE-patterns belonging to five serotypes: S.4,5,12:i:-, Rissen, Typhimurium, Infantis and Derby. Resistance to ampicillin, sulfamethoxazole, tetracycline and/or chloramphenicol was detected depending on serotypes. 16S rRNA-based bacterial diversity analyses showed that Salmonella surface associated communities were highly dominated by the Moraxellaceae family with a clear site-specific composition suggesting a persistent colonization of the pig slaughterhouse. Cleaning and disinfection procedures did not lead to a modification of Salmonella susceptibility to antimicrobials in this short-term study but they tended to significantly reduce bacterial diversity and favored some genera such as Rothia and Psychrobacter. Such data participate to the construction of a comprehensive view of Salmonella ecology and antimicrobial resistance emergence in food environments in relation with cleaning and disinfection procedures

A new method for the evaluation of the end-to-end distance of the knee ligaments and popliteal complex during passive knee flexion

Background: Accurate knowledge about the length variation of the knee ligaments (ACL, PCL, MCL and LCL) and the popliteal complex during knee flexion/extension is essential for modelling and clinical applications. The aimof the present study is to provide this information by using an original technique able to faithfully reproduce the continuous passive knee flexion–extension kinematics and to reliably identify each ligament/tendon attachment site. Methods: Twelve lower limbs (femur, tibia, fibula, patella)were tested and set inmotion (0–120°) using an ad hoc rig. Tibio-femoral kinematics was obtained using an optoelectronic system. A 3D digital model of each bone was obtained using low-dosage stereoradiography. Knee specimens were dissected and the insertion of each ligament and popliteal complex were marked with radio opaque paint. ACL, PCL and MCL were separated into two bundles. Bone epiphyses were CT-scanned to obtain a digital model of each ligament insertion. Bones and attachment site models were registered and the end-to-end distance variation of each ligament/tendon was computed over knee flexion. Results: A tibial internal rotation of 18°±4° with respect to the femur was observed. The different bundles of the ACL, MCL and LCL shortened, whereas all bundles of the PCL lengthened. The popliteal complex was found to shorten until 30° of knee flexion and then to lengthen. Conclusion: The end-to-end distance variation of the knee ligaments and popliteal complex can be estimated during knee flexion using a robust and reliable method based on marking the ligaments/tendon insertions with radiopaque paint. Level of evidence: Level IVThanks to Ann-Laure Pollastri for her technical support and to Louis Dagneaux for helping during the experimental session. The authors also thank the ParisTech BiomecAM chair program on subject-specific musculoskeletal modelling. This research was approved by the ethics committee of the human anatomy lab of the University of Caen (Basse Normandie, France)

Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis

BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF. METHODS: We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF. RESULTS: Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001). CONCLUSIONS: NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome. LAY SUMMARY: Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF

Women and postfertilization effects of birth control: consistency of beliefs, intentions and reported use

BACKGROUND: This study assesses the consistency of responses among women regarding their beliefs about the mechanisms of actions of birth control methods, beliefs about when human life begins, the intention to use or not use birth control methods that they believe may act after fertilization or implantation, and their reported use of specific methods. METHODS: A questionnaire was administered in family practice and obstetrics and gynecology clinics in Salt Lake City, Utah, and Tulsa, Oklahoma. Participants included women ages 18–50 presenting for any reason and women under age 18 presenting for family planning or pregnancy care. Analyses were based on key questions addressing beliefs about whether specific birth control methods may act after fertilization, beliefs about when human life begins, intention to use a method that may act after fertilization, and reported use of specific methods. The questionnaire contained no information about the mechanism of action of any method of birth control. Responses were considered inconsistent if actual use contradicted intentions, if one intention contradicted another, or if intentions contradicted beliefs. RESULTS: Of all respondents, 38% gave consistent responses about intention to not use or to stop use of any birth control method that acted after fertilization, while 4% gave inconsistent responses. The corresponding percentages for birth control methods that work after implantation were 64% consistent and 2% inconsistent. Of all respondents, 34% reported they believed that life begins at fertilization and would not use any birth control method that acts after fertilization (a consistent response), while 3% reported they believed that life begins at fertilization but would use a birth control method that acts after fertilization (inconsistent). For specific methods of birth control, less than 1% of women gave inconsistent responses. A majority of women (68% or greater) responded accurately about the mechanism of action of condoms, abstinence, sterilization, and abortion, but a substantial percentage of women (between 19% and 57%) were uncertain about the mechanisms of action of oral contraceptives, intrauterine devices (IUDs), Depo-Provera, or natural family planning. CONCLUSION: Women who believe that life begins at fertilization may not intend to use a birth control method that could have postfertilization effects. More research is needed to understand the relative importance of postfertilization effects for women in other populations, and in relation to other properties of and priorities for birth control methods. However, many women were uncertain about the mechanisms of action of specific methods. To respect the principles of informed consent, some women may need more education about what is known and not known about the mechanisms of action of birth control methods