Contributions of the qualitative Qualicor study embedded in a cohort study on the circumstances of SARS-CoV 2 infection in France.

OBJECTIVES: This study aims to understand a major result of ComCor, an online epidemiological study conducted to identify the circumstances of COVID-19 infection in France from 2020 to 2022: One third of respondents reported ignoring the circumstances of their infection. METHODS: We conducted a qualitative study through semi-structured interviews, diagnosed in spring or summer 2021. Interviews were audio recorded, transcribed, and thematically analyzed. RESULTS: Fifty interviews were conducted. Half of the participants in Qualicor were able to identify several at-risk situations, most often involving their entourage (family, friends, colleagues), but were uncertain as to which specific situation was the source of infection. Less than one quarter strongly suspected a specific situation without certainty, a similar proportion were unable to identify any circumstances, and only two people were certain about the origin of the infection. Several factors contributed to this lack of knowledge: a desire to conceal these circumstances (in a few rare cases), limitations of the questionnaire, lack of knowledge about how the virus is transmitted, selective perception of at-risk situations, co-existence of several possible sources of infection, and the difficulty of taking an objective view of certain circumstances of transmission. CONCLUSION: Our study shows the benefits of a mixed approach designed to better understand the perception of Covid 19 contamination circumstances in the French population. It also highlights the need to strengthen or improve communication on modes of virus transmission, especially airborne transmission, and the importance of maintaining certain preventive behaviors after vaccination.

Variability and uncertainty of 18F-FDG PET imaging protocols for assessing inflammation in atherosclerosis: suggestions for improvement.

UNLABELLED: PET with (18)F-FDG shows promise for the evaluation of metabolic activities in atherosclerotic plaques. Although recommendations regarding the acquisition and measurement protocols to be used for (18)F-FDG PET imaging of atherosclerosis inflammation have been published, there is no consensus regarding the most appropriate protocols, and the image reconstruction approach has been especially overlooked. Given the small size of the targeted lesions, the reconstruction and measurement methods might strongly affect the results. We determined the differences in results due to the protocol variability and identified means of increasing the measurement reliability. METHODS: An extensive literature search was performed to characterize the variability in atherosclerosis imaging and quantification protocols. Highly realistic simulations of atherosclerotic carotid lesions based on real patient data were designed to determine how the acquisition and processing protocol parameters affected the measured values. RESULTS: In 49 articles, we identified 53 different acquisition protocols, 51 reconstruction protocols, and 46 quantification methods to characterize atherosclerotic lesions from (18)F-FDG PET images. The most important parameters affecting the measurement accuracy were the number of iterations used for reconstruction and the postfiltering applied to the reconstructed images, which could together make the measured standardized uptake values (SUVs) vary by a factor greater than 3. Image sampling, acquisition duration, and metrics used for the measurements also affected the results to a lesser extent (SUV varying by a factor of 1.3 at most). For an acceptable SUV variability, the lowest bias in SUV was observed using an 8-min acquisition per bed position; ordered-subset expectation maximization reconstruction with at least 120 maximum likelihood expectation maximization equivalent iterations, including a point spread function model using a 1 mm(3) voxel size; and no postfiltering. Because of the partial-volume effect, measurement bias remained greater than 60%. The use and limitations of the target-to-blood activity ratio metrics are also presented and discussed. CONCLUSION: (18)F-FDG PET protocol harmonization is needed in atherosclerosis imaging. Optimized protocols can significantly reduce the measurement errors in wall activity estimates, but PET systems with higher spatial resolution and advanced partial-volume corrections will be required to accurately assess plaque inflammation from (18)F-FDG PET.

Potato fiber protects the small intestinal wall against the toxic influence of acrylamide.

OBJECTIVE: Acrylamide is a neurotoxic, genotoxic substance present in many commonly consumed food products and has been shown to have carcinogenic effects in rodents. The protective effects (if any) of potato fiber preparations, composed of cell wall material from potatoes, against the toxic influence of dietary acrylamide on the small intestinal wall were investigated. METHODS: Male mice of the BALB/c strain were used in the study. Acrylamide was administered to the mice in their drinking water (0.5 mg/kg of body weight per day) and one of two types of potato fiber preparations (heated or raw potato fiber preparation) was added to their feed (2% addition to their feed). Histomorphometry of the small intestinal wall, hemoglobin adducts of acrylamide, animal weight, and feed and water consumption analyses were performed. RESULTS: Acrylamide altered the morphology and histology of the small intestinal wall, decreasing proliferation, myenteron and submucosal thicknesses, villus length, fractal dimension, crypt depth, crypt number, and the small intestinal absorptive surface. Conversely, apoptosis, hemoglobin adduct levels, intensity of epithelium staining, enterocyte number, villus epithelial thickness, and crypt width and parameters associated with nerve ganglia were increased. The two potato fiber preparations that were used abolished the negative influences of acrylamide on the small intestinal wall and had no influence on the hemoglobin adduct levels of acrylamide. CONCLUSION: The negative impact of acrylamide on the histologic structure, regeneration, and innervation of the small intestinal wall and the absorptive function of the small intestinal mucosa can be abolished by dietary potato fiber preparations.