Accumulation and Changes in Composition of Collagens in Subcutaneous Adipose Tissue After Bariatric Surgery

International audienceExtracellular matrix (ECM) in sc adipose tissue (scAT) undergoes pathological remodeling during obesity. However, its evolution during weight loss remains poorly explored.Objective:The objective of the investigation was to study the histological, transcriptomic, and physical characteristics of scAT ECM remodeling during the first year of bariatric surgery (BS)-induced weight loss and their relationships with metabolic and bioclinical improvements.Design, Setting, Patients, and Interventions:A total of 118 morbidly obese candidates for BS were recruited and followed up during 1 year after BS.Main Outcome Measures:scAT surgical biopsy and needle aspiration as well as scAT stiffness measurement were performed in three subgroups before and after BS. Fourteen nonobese, nondiabetic subjects served as controls.Results:Significantly increased picrosirius-red-stained collagen accumulation in scAT after BS was observed along with fat mass loss, despite metabolic and inflammatory improvements and undetectable changes of scAT stiffness. Collagen accumulation positively associated with M2-macrophages (CD163+ cells) before BS but negatively afterward. Expression levels of genes encoding ECM components (eg, COL3A1, COL6A1, COL6A2, ELN), cross-linking enzymes (eg, lysyl oxidase [LOX], LOXL4, transglutaminase), metalloproteinases, and their inhibitors were modified 1 year after BS. LOX expression and protein were significantly decreased and associated with decreased fat mass as well as other cross-linking enzymes. Although total collagen I and VI staining decreased 1 year after BS, we found increased degraded collagen I and III in scAT, suggesting increased degradation.Conclusions:After BS-induced weight loss and related metabolic improvements, scAT displays major collagen remodeling with an increased picrosirius-red staining that relates to increased collagen degradation and importantly decreased cross-linking. These features are in agreement with adequate ECM adaptation during fat mass loss- See more at: http://press.endocrine.org/doi/10.1210/jc.2015-3348#sthash.PLeUvzKd.dpu

Accuracy of FibroScan Controlled Attenuation Parameter and Liver Stiffness Measurement in Assessing Steatosis and Fibrosis in Patients With Non-alcoholic Fatty Liver Disease.

BACKGROUND & AIMS: We estimated the accuracy of FibroScan vibration-controlled transient elastography controlled attenuation parameter (CAP) and liver stiffness measurements (LSMs) in assessing steatosis and fibrosis in patients with suspected NAFLD. METHODS: We collected data from 450 consecutive adults who underwent liver biopsy analysis for suspected NAFLD at 7 centers in the United Kingdom from March 2014 through January 2017. FibroScan examinations with M or XL probe were completed within the 2 weeks of the biopsy analysis (404 had a valid examination). The biopsies were scored by 2 blinded expert pathologists according to non-alcoholic steatohepatitis clinical research network criteria. Diagnostic accuracy was estimated using the area under the receiver operating characteristic curves (AUROC) for the categories of steatosis and fibrosis. We assessed effects of disease prevalence on positive and negative predictive values. For LSMs, the effects of histological parameters and probe type were appraised using multivariable analysis. RESULTS: Using biopsy analysis as the reference standard, we found that CAP identified patients with steatosis with an AUROCs of 0.87 (95% CI, 0.82-0.92) for S≥S1, 0.77 (95% CI, 0.71-0.82) for S≥S2, and 0.70 (95% CI, 0.64-0.75) for S=S3. Youden cut-off values for S≥S1, S≥S2 and S≥S3 were 302 dB/m, 331 dB/m, and 337 dB/m respectively. LSM identified patients with fibrosis with AUROCs of 0.77 (95% CI, 0.72-0.82) for F≥F2, 0.80 (95% CI, 0.75-0.84) for F≥F3, and 0.89 (95% CI, 0.84-0.93) for F=F4. Youden cut-off values for F≥F2, F≥F3 and F=F4 were 8.2 kPa, 9.7 kPa, and 13.6 kPa respectively. Applying the optimal cut-off values, determined from this cohort, to populations of lower fibrosis prevalence increased negative predictive values and reduced positive predictive values. Multivariable analysis found that the only parameter that significantly affect LSMs was fibrosis stage (P<10-16); we found no association with steatosis or probe type. CONCLUSIONS: In a prospective analysis of patients with NAFLD, we found CAP and LSMs by FibroScan to assess liver steatosis and fibrosis, respectively, with AUROC values ranging from 0.7 to 0.89. Probe type and steatosis did not affect LSMs

Towards harmonization of image velocimetry techniques for river surface velocity observations

Since the turn of the 21st Century, image based velocimetry techniques have become an increasingly popular approach for determining open-channel flow in a range of hydrological settings across Europe, and beyond. Simultaneously, a range of large-scale image velocimetry algorithms have been developed, equipped with differing image pre-processing, and analytical capabilities. Yet in operational hydrometry, these techniques are utilised by few competent authorities. Therefore, imagery collected for image velocimetry analysis, along with validation data is required both to enable inter-comparisons between these differing approaches and to test their overall efficacy. Through benchmarking exercises, it will be possible to assess which approaches are best suited for a range of fluvial settings, and to focus future software developments. Here we collate, and describe datasets acquired from six countries across Europe and Asia, consisting of videos that have been subjected to a range of pre-processing, and image velocimetry analysis (Perks et al., 2019, https://doi.org/10.4121/uuid:34764be1-31f9-4626-8b11-705b4f66b95a). Validation data is available for 12 of the 13 case studies presented enabling these data to be used for validation and accuracy assessment

Traitement et analyse du signal ultrasonore pour la caractérisation de l'os cortical

This work deals with the ultrasonic characterization of cortical bone. In a first part, the signals acquired with a 1-MHz axial transmission device are analyzed. A later contribution occuring after the first arriving signal is studied after the application of a wave separation procedure. This contribution is shown to be of interest for the ultrasonic characterization of cortical bone. Indeed, experiments performed in vitro on human radii show that this contribution is associated with a flexural wave guided which is dependent on the cortical thickness. In addition, this contribution has a lower frequency content than the first arriving signal and is associated with a different propagation mode. Therefore, a more thorough analysis of the ultrasonic signals enables a multi-modal/multi-frequency approach. In a second part, the ultrasonic attenuation is evaluated in an in vitro experimental study on bovine cortical bone samples. Ultrasonic attenuation is shown to be dependent on bone properties and micro-structure. Furthermore, this parameter seems to be more sensitive than the longitudinal wave velocity to bone parameters. Attenuation, in combination with ultrasonic wave velocity, is of interest and may provide a more comprehensive characterization of cortical boneCe travail de thèse porte sur l’analyse et le traitement des signaux ultrasonores pour la caractérisation de l’os cortical. La première partie est dédiée à l’analyse des signaux acquis par un prototype de sonde de transmission axiale à 1 MHz. Nous montrons qu’une contribution arrivant après le premier signal présente un intérêt pour la caractérisation ultrasonore de l’os cortical. En effet, cette contribution évaluée sur des radius humains in vitro est associée à une onde de flexion propagée dans l’os qui est dépendante de l’épaisseur corticale. L’analyse de cette contribution a nécessité le développement d’une technique de séparation d’ondes. Cette contribution étant plus basse fréquence que le premier signal et associée à un mode de propagation différent, nous montrons ainsi qu’une analyse plus poussée du signal peut permettre une approche multi-modes/multi-fréquences. Dans une seconde partie, nous montrons l’intérêt de l’évaluation de l’atténuation ultrasonore pour la caractérisation de l’os cortical. Lors d’une étude expérimentale in vitro sur des échantillons corticaux bovins, nous montrons la dépendance d’un paramètre d’atténuation aux propriétés osseuses et à la micro-structure. De plus, ce paramètre semble plus sensible aux propriétés osseuses que ne l’est la vitesse de l’onde longitudinale. Ainsi, l’atténuation évaluée en complément de la vitesse pourrait permettre de caractériser de manière plus complète l’os cortica

Signal processing and analysis of ultrasound dedicated to cortical bone characterization

Ce travail de thèse porte sur l’analyse et le traitement des signaux ultrasonores pour la caractérisation de l’os cortical. La première partie est dédiée à l’analyse des signaux acquis par un prototype de sonde de transmission axiale à 1 MHz. Nous montrons qu’une contribution arrivant après le premier signal présente un intérêt pour la caractérisation ultrasonore de l’os cortical. En effet, cette contribution évaluée sur des radius humains in vitro est associée à une onde de flexion propagée dans l’os qui est dépendante de l’épaisseur corticale. L’analyse de cette contribution a nécessité le développement d’une technique de séparation d’ondes. Cette contribution étant plus basse fréquence que le premier signal et associée à un mode de propagation différent, nous montrons ainsi qu’une analyse plus poussée du signal peut permettre une approche multi-modes/multi-fréquences. Dans une seconde partie, nous montrons l’intérêt de l’évaluation de l’atténuation ultrasonore pour la caractérisation de l’os cortical. Lors d’une étude expérimentale in vitro sur des échantillons corticaux bovins, nous montrons la dépendance d’un paramètre d’atténuation aux propriétés osseuses et à la micro-structure. De plus, ce paramètre semble plus sensible aux propriétés osseuses que ne l’est la vitesse de l’onde longitudinale. Ainsi, l’atténuation évaluée en complément de la vitesse pourrait permettre de caractériser de manière plus complète l’os corticalThis work deals with the ultrasonic characterization of cortical bone. In a first part, the signals acquired with a 1-MHz axial transmission device are analyzed. A later contribution occuring after the first arriving signal is studied after the application of a wave separation procedure. This contribution is shown to be of interest for the ultrasonic characterization of cortical bone. Indeed, experiments performed in vitro on human radii show that this contribution is associated with a flexural wave guided which is dependent on the cortical thickness. In addition, this contribution has a lower frequency content than the first arriving signal and is associated with a different propagation mode. Therefore, a more thorough analysis of the ultrasonic signals enables a multi-modal/multi-frequency approach. In a second part, the ultrasonic attenuation is evaluated in an in vitro experimental study on bovine cortical bone samples. Ultrasonic attenuation is shown to be dependent on bone properties and micro-structure. Furthermore, this parameter seems to be more sensitive than the longitudinal wave velocity to bone parameters. Attenuation, in combination with ultrasonic wave velocity, is of interest and may provide a more comprehensive characterization of cortical bon

Traitement et analyse du signal ultrasonore pour la caractérisation de l'os cortical

Ce travail de thèse porte sur l analyse et le traitement des signaux ultrasonores pour la caractérisation de l os cortical. La première partie est dédiée à l analyse des signaux acquis par un prototype de sonde de transmission axiale à 1 MHz. Nous montrons qu une contribution arrivant après le premier signal présente un intérêt pour la caractérisation ultrasonore de l os cortical. En effet, cette contribution évaluée sur des radius humains in vitro est associée à une onde de flexion propagée dans l os qui est dépendante de l épaisseur corticale. L analyse de cette contribution a nécessité le développement d une technique de séparation d ondes. Cette contribution étant plus basse fréquence que le premier signal et associée à un mode de propagation différent, nous montrons ainsi qu une analyse plus poussée du signal peut permettre une approche multi-modes/multi-fréquences. Dans une seconde partie, nous montrons l intérêt de l évaluation de l atténuation ultrasonore pour la caractérisation de l os cortical. Lors d une étude expérimentale in vitro sur des échantillons corticaux bovins, nous montrons la dépendance d un paramètre d atténuation aux propriétés osseuses et à la micro-structure. De plus, ce paramètre semble plus sensible aux propriétés osseuses que ne l est la vitesse de l onde longitudinale. Ainsi, l atténuation évaluée en complément de la vitesse pourrait permettre de caractériser de manière plus complète l os corticalThis work deals with the ultrasonic characterization of cortical bone. In a first part, the signals acquired with a 1-MHz axial transmission device are analyzed. A later contribution occuring after the first arriving signal is studied after the application of a wave separation procedure. This contribution is shown to be of interest for the ultrasonic characterization of cortical bone. Indeed, experiments performed in vitro on human radii show that this contribution is associated with a flexural wave guided which is dependent on the cortical thickness. In addition, this contribution has a lower frequency content than the first arriving signal and is associated with a different propagation mode. Therefore, a more thorough analysis of the ultrasonic signals enables a multi-modal/multi-frequency approach. In a second part, the ultrasonic attenuation is evaluated in an in vitro experimental study on bovine cortical bone samples. Ultrasonic attenuation is shown to be dependent on bone properties and micro-structure. Furthermore, this parameter seems to be more sensitive than the longitudinal wave velocity to bone parameters. Attenuation, in combination with ultrasonic wave velocity, is of interest and may provide a more comprehensive characterization of cortical bonePARIS12-Bib. électronique (940280011) / SudocPARIS-EST-Université (770839901) / SudocSudocFranceF

Changes in the distribution of colonising and infecting Candida spp. isolates, antifungal drug consumption and susceptibility in a French intensive care unit: A 10-year study

International audienceMonitoring fungal ecology and resistance to antifungal agents within intensive care units (ICU) is essential for the management of invasive fungal infections. Therefore, a retrospective descriptive study was carried in the ICU of Nimes University Hospital, France, from 2007 to 2016. As the majority of invasive fungal infections in ICU are caused by Candida species, the study objectives were to describe Candida species distribution, to assess candidaemia incidence and to monitor the antifungal drug susceptibility of Candida isolates and the consumption of antifungal agents. Among the recorded invasive Candida infections (n=244), 43% were intra-abdominal and 22% bloodstream infections. Candida albicans was the most frequent species (55.8%), followed by Candida glabrata (14.1%), Candida tropicalis (10%), Candida parapsilosis (8%) and Candida krusei (5.3%). Candidaemia incidence was 4.49 per 1000 admissions. The mean consumption of antifungal agents was of 170.5 defined daily doses (DDD) for 1000 hospital days (HD) per year. Changes in antifungal drug consumption were observed, with an increased use of echinocandins (from 17.96 DDD/1000 HD in 2007 to 48.76 DDD/1000 HD in 2016), and the total treatment cost tripled during the study period. No significant change in fungal ecology or in the emergence of resistant species was observed; indeed, only 1.1% of isolates presented an unusual resistance to antifungal agents