CT Characteristics of Pheochromocytoma: Relevance for the Evaluation of Adrenal Incidentaloma.

BACKGROUND: Up to 7% of all adrenal incidentalomas (AIs) are pheochromocytomas (PCCs). In the evaluation of AI, it is generally recommended that PCC be excluded by measurement of plasma-free or 24-hour urinary fractionated metanephrines. However, recent studies suggest that biochemical exclusion of PCC not be performed for lesions with CT characteristics of an adrenocortical adenoma (ACA). AIM: To determine the proportion of PCCs with ACA-like attenuation or contrast washout on CT. METHODS: For this multicenter retrospective study, two central investigators independently analyzed the CT reports of 533 patients with 548 histologically confirmed PCCs. Data on tumor size, unenhanced Hounsfield units (HU), absolute percentage washout (APW), and relative percentage washout (RPW) were collected in addition to clinical parameters. RESULTS: Among the 376 PCCs for which unenhanced attenuation data were available, 374 had an attenuation of >10 HU (99.5%). In the two exceptions (0.5%), unenhanced attenuation was exactly 10 HU, which lies just within the range of ≤10 HU that would suggest a diagnosis of ACA. Of 76 PCCs with unenhanced HU > 10 and available washout data, 22 (28.9%) had a high APW and/or RPW, suggestive of ACA. CONCLUSION: Based on the lack of PCCs with an unenhanced attenuation of <10 HU and the low proportion (0.5%) of PCCs with an attenuation of 10 HU, it seems reasonable to abstain from biochemical testing for PCC in AIs with an unenhanced attenuation of ≤10 HU. The assessment of contrast washout, however, is unreliable for ruling out PCC

Etude Multi-Echelle et Multi-Physique de l’Ordre d’Introduction des Phases d’une Emulsion

International audiencePour optimiser la stabilité d'une émulsion, une investigation multi-échelle est nécessaire. Les moyens préventifs classiques d'étude se font par l'analyse de l'inversion de phase (H/E ou E/H) ou par le changement de paramètres, tels que la composition, le procédé d'émulsification et les conditions environnementales. Ce travail consiste en une étude préliminaire multiphysique et multi échelle, par un changement d'ordre d'introduction des phases. Les caractéristiques mécaniques et électriques sont étudiées à deux échelles d'investigation par deux nouvelles techniques : rhéologie ultrasonore et impédancemétrie radiofréquence. La comparaison des caractéristiques, macroscopiques et mésoscopiques, cherche à identifier les grandeurs d'influence précurseurs d'une (in)stabilité

Multimodal O/W emulsion structuration characterization using water and emulsion thickening ranges

International audienceTo ensure the stability of emulsions, a thickening agent is often used to induce a higher viscosity of the continuous aqueous phase and reduce the possibility of gravitational separation(1). In some cases, these agents require a base to increase the thickening of emulsions and this process can be observed by following the viscosity as a function of the pH(2). Our work attempts to show the link between gelation process and emulsion stability investigated through the use of two innovative measurement techniques at the mesoscopic scale: micro-rheology by ultrasounds and electrical complex dielectric characterization by contactless radiofrequency spectroscopy. The first one allows to better understand the emulsion structuration through the measurement of the visco-elastic properties(3). The second one is used to get information about polarizability of the mixing and conductivity of the continuous phase(4). A comparison is done between the aqueous phase (water + Carbopol® CETD 2050: gel phase) and the equivalent emulsion (aqueous phase + oil: Isopropyl Palmitate + surfactants: Eumulgin® SMO 20/Cutina® GMS V), for different pH by changing the amount of base (Triethanolamine). Both are made on the same pH range (3.5 – 6) to emphasize steric behavior rather than the electrical one. The mesoscopic characterizations highlight the impact of oil on the gelation state. They also show the limits of pH adjustments on increasing viscosity and electronic repulsion between oil droplets, which are stability-promoting factors. The results are completed by complementary classical characterizations such as conductivity, rheological and optical microscopy measurements, to correlate them with documented macroscopic knowledge(5). (1) Piorkowski D.T., et al, 2014(2) Abdolmaleki K., et al, 2016(3) Gauthier V., et al, 2017(4) Dinh T.H.N., et al, 2016(5) Gutowski I., et al, 200

Phase Inversion Temperature Monitoring with Contactless RF Impedancemetry for O/W Emulsion Optimization

International audienceThe phase inversion temperature (PIT) designates the temperature for which a heated emulsion changes from an Oil-in-Water (O/W) state to a Water-in-Oil (W/O) state during a rise in temperature[1]. This important parameter is used to optimize the emulsion stability by finding an optimal storage condition or on the contrary to determine the optimal formulation for oil recovery[2]. The PIT can be affected by three main variables: formulation, composition and protocol[3], and several technics can be used to identify this singular temperature. It is mostly determined by conductometry at a macroscopic scale and it can also be followed by viscosity measurements or endothermic transition determination[4]. In order to optimize the formulation, it is interesting to evaluate the PIT accurately at a mesoscopic scale. Our work aims to identify the PIT and the inner changes taking place in O/W emulsions by monitoring the complex dielectric properties at radiofrequency (RF) range (140 MHz). A contactless RF impedance measuring device developed by the SATIE Laboratory is used[5]. This non-destructive and non-invasive technique allows to measure simultaneously conductivity (σ) and permittivity (ε) evolutions of complex fluids. The first one is directly related to the charge mobility while the second one is related to the polarizability. The ratio between the dissipated and stored energies provides information on the internal structure of the studied environment.The measurement results obtained with our RF impedancemeter are compared with those obtained by low frequency conductivity. The measurements are carried out in parallel between 10 to 90°C for eleven different chosen compositions. This comparison shows phenomena measured respectively at two scales of investigation: mesoscopic and macroscopic. This comparison helps to link the electrical evolutions inside the emulsions. These measurements also enable to monitor the stability of these emulsions over time and to correlate them with the overall structuration of the emulsions. These results were supplemented by additional observations by optical microscopy and ultrasonic rheology.[1]K. Shinoda and H. Arai, “The Effect of Phase Volume on the Phase Inversion Temperature of Emulsions Stabilized with Nonionic Surfactants,” J. Colloid Interface Sci., vol. 25, no. 3, pp. 429–431, 1967, doi: https://doi.org/10.1016/0021-9797(67)90051-3.[2]G. Lemahieu, J. F. Ontiveros, V. Molinier, and J.-M. Aubry, “Using the dynamic Phase Inversion Temperature (PIT) as a fast and effective method to track optimum formulation for Enhanced Oil Recovery,” J. Colloid Interface Sci., vol. 557, pp. 746–756, 2019, doi: https://doi.org/10.1016/j.jcis.2019.09.050.[3]J. L. Salager, “Emulsion Phase Inversion Phenomena,” in Emulsions and Emulsion Stability, 2006, pp. 185–226.[4]V. B. Souza, L. S. Spinelli, G. Gonzalez, and C. R. E. Mansur, “Determination of the phase inversion temperature of orange oil/water emulsions by rheology and microcalorimetry,” Anal. Lett., vol. 42, no. 17, pp. 2864–2878, 2009, doi: 10.1080/00032710903137392.[5]X. Zhou, “Nouveau systeme de controle radiofréquence de micro-algues pour la santé et le bien-être,” Université de Cergy Pontoise, 2016

Multimodal O/W emulsion structuration characterization using water and emulsion thickening ranges

International audienceTo ensure the stability of emulsions, a thickening agent is often used to induce a higher viscosity of the continuous aqueous phase and reduce the possibility of gravitational separation(1). In some cases, these agents require a base to increase the thickening of emulsions and this process can be observed by following the viscosity as a function of the pH(2). Our work attempts to show the link between gelation process and emulsion stability investigated through the use of two innovative measurement techniques at the mesoscopic scale: micro-rheology by ultrasounds and electrical complex dielectric characterization by contactless radiofrequency spectroscopy. The first one allows to better understand the emulsion structuration through the measurement of the visco-elastic properties(3). The second one is used to get information about polarizability of the mixing and conductivity of the continuous phase(4). A comparison is done between the aqueous phase (water + Carbopol® CETD 2050: gel phase) and the equivalent emulsion (aqueous phase + oil: Isopropyl Palmitate + surfactants: Eumulgin® SMO 20/Cutina® GMS V), for different pH by changing the amount of base (Triethanolamine). Both are made on the same pH range (3.5 – 6) to emphasize steric behavior rather than the electrical one. The mesoscopic characterizations highlight the impact of oil on the gelation state. They also show the limits of pH adjustments on increasing viscosity and electronic repulsion between oil droplets, which are stability-promoting factors. The results are completed by complementary classical characterizations such as conductivity, rheological and optical microscopy measurements, to correlate them with documented macroscopic knowledge(5). (1) Piorkowski D.T., et al, 2014(2) Abdolmaleki K., et al, 2016(3) Gauthier V., et al, 2017(4) Dinh T.H.N., et al, 2016(5) Gutowski I., et al, 200

Another Multiparametric Way In Planning Of Experiments For O/W Emulsion Design

International audienceDefining an effective way to design stable emulsions with limited resources is a challenge that every laboratory is facing at least once. Two ways of experiments have been trending as a cost-and-time-efficient method to explore factor impact (environmental ones such as temperature, or inherent like composition), and finally optimize formulations: i. multidimensional methods based on a dichotomic approach which require to change parameters one by one. These methods are commonly known to be quite ineffective to accurately correlate parameters; ii. in Design of Experiments (DOE), only a restricted number of experiments are required to understand, develop and predict new paths to formulation or new theories, though it usually requires specific and expensive software and specific mathematic skills. Our work aims to show a resource-effective way to plan experiments based on a random equidistribution of raw material ratios (Oil/Surfactants/Water: O/S/W) in order to identify O/W emulsion stability condition boundary

Another Multiparametric Way In Planning Of Experiments For O/W Emulsion Design

International audienceDefining an effective way to design stable emulsions with limited resources is a challenge that every laboratory is facing at least once. Two ways of experiments have been trending as a cost-and-time-efficient method to explore factor impact (environmental ones such as temperature, or inherent like composition), and finally optimize formulations: i. multidimensional methods based on a dichotomic approach which require to change parameters one by one. These methods are commonly known to be quite ineffective to accurately correlate parameters; ii. in Design of Experiments (DOE), only a restricted number of experiments are required to understand, develop and predict new paths to formulation or new theories, though it usually requires specific and expensive software and specific mathematic skills. Our work aims to show a resource-effective way to plan experiments based on a random equidistribution of raw material ratios (Oil/Surfactants/Water: O/S/W) in order to identify O/W emulsion stability condition boundary

sHSPs under temperature and pressure: The opposite behaviour of lens alpha-crystallins and yeast HSP26

International audienceSmall angle X-ray scattering was used to follow the temperature and pressure induced structural transitions of polydisperse native calf lens alpha-crystallins and recombinant human alphaB-crystallins and of monodisperse yeast HSP26. The alpha-crystallins were known to increase in size with increasing temperature, whereas HSP26 partially dissociates into dimers. SAXS intensity curves demonstrated that the average 40-mer calf alpha-crystallin converted into 80-mer in a narrow temperature range, from 60 to 69 °C, whereas the average 30-mer alphaB-crystallin was continuously transformed into 60-mer at lower temperature, from 40 to 60 °C. These temperature-induced transitions were irreversible. Similar transitions, yet reversible, could be induced with pressure in the 100 to 300 MPa pressure range. Moreover, temperature and pressure could be combined to lower the transition temperatures. On the other hand, SAXS curves recorded during pressure scans from 0.1 to 200 MPa with monodisperse 24-mer HSP26 revealed dissociation of the 24-mer into dimers. This dissociation was complete and reversible. Whatever the sHSP, a decrease of partial specific volume was found to be associated with the pressure induced quaternary structure transitions, in agreement with the hypothesis that such transitions represent a first step on the protein denaturation pathway

Soft Matter Characterization From Ultrasonic Microrheology and Fractional Calculus

International audienc