Processing of blood samples influences PBMC viability and outcome of cell-mediated immune responses in antiretroviral therapy-naïve HIV-1-infected patients

AbstractIntracellular cytokine staining (ICS) assay is increasingly used in vaccine clinical trials to measure antigen-specific T-cell mediated immune (CMI) responses in cryopreserved peripheral blood mononuclear cells (PBMCs) and whole blood. However, recent observations indicate that several parameters involved in blood processing can impact PBMC viability and CMI responses, especially in antiretroviral therapy (ART)-naïve HIV-1-infected individuals.In this phase I study (NCT01610427), we collected blood samples from 22 ART-naïve HIV-1-infected adults. PBMCs were isolated and processed for ICS assay. The individual and combined effects of the following parameters were investigated: time between blood collection and PBMC processing (time-to-process: 2, 7 or 24h); time between PBMC thawing and initiation of in vitro stimulation with HIV-1 antigens (resting-time: 0, 2, 6 and 18h); and duration of antigen-stimulation in PBMC cultures (stimulation-time: 6h or overnight). The cell recovery after thawing, cell viability after ICS and magnitude of HIV-specific CD8+ T-cell responses were considered to determine the optimal combination of process conditions. The impact of time-to-process (2 or 4h) on HIV-specific CD8+ T-cell responses was also assessed in a whole blood ICS assay.A higher quality of cells in terms of recovery and viability (up to 81% and >80% respectively) was obtained with shorter time-to-process (less than 7h) and resting-time (less than 2h) intervals. Longer (overnight) rather than shorter (6h) stimulation-time intervals increased the frequency of CD8+-specific T-cell responses using ICS in PBMCs without change of the functionality. The CD8+ specific T-cell responses detected using fresh whole blood showed a good correlation with the responses detected using frozen PBMCs.Our results support the need of standardized procedures for the evaluation of CMI responses, especially in HIV-1-infected, ART-naïve patients

Control of Rest:Activity by a Dopaminergic Ultradian Oscillator and the Circadian Clock

There is long-standing evidence for rhythms in locomotor activity, as well as various other aspects of physiology, with periods substantially shorter than 24 h in organisms ranging from fruit flies to humans. These ultradian oscillations, whose periods frequently fall between 2 and 6 h, are normally well integrated with circadian rhythms; however, they often lack the period stability and expression robustness of the latter. An adaptive advantage of ultradian rhythms has been clearly demonstrated for the common vole, suggesting that they may have evolved to confer social synchrony. The cellular substrate and mechanism of ultradian rhythm generation have remained elusive so far, however recent findings—the subject of this review—now indicate that ultradian locomotor rhythms rely on an oscillator based on dopamine, dubbed the dopaminergic ultradian oscillator (DUO). These findings also reveal that the DUO period can be lengthened from <4 to >48 h by methamphetamine treatment, suggesting that the previously described methamphetamine-sensitive (circadian) oscillator represents a long-period manifestation of the DUO

« Une infime poignée de traîtres » ?

Le jeune Paul apparaît au premier abord comme un garçon que l’on pourrait qualifier d’ordinaire. Second enfant d’une famille qui en compte quatre, il fréquente l’école Saint-Luc à Mons où il est décrit comme un bon élève et un brave enfant dont personne n’a jamais eu à se plaindre. Fils d’artisan, il vit avec sa famille dans une maison de commerce de Mons. En dehors de l’école, il occupe son temps en fréquentant notamment un mouvement de jeunesse. Si ce tableau ne semble rien comporter de not..

What Does the History of Research on the Repair of DNA Double-Strand Breaks Tell Us?—A Comprehensive Review of Human Radiosensitivity

Our understanding of the molecular and cellular response to ionizing radiation (IR) has progressed considerably. This is notably the case for the repair and signaling of DNA double-strand breaks (DSB) that, if unrepaired, can result in cell lethality, or if misrepaired, can cause cancer. However, through the different protocols, techniques, and cellular models used during the last four decades, the DSB repair kinetics and the relationship between cellular radiosensitivity and unrepaired DSB has varied drastically, moving from all-or-none phenomena to very complex mechanistic models. To date, personalized medicine has required a reliable evaluation of the IR-induced risks that have become a medical, scientific, and societal issue. However, the molecular bases of the individual response to IR are still unclear: there is a gap between the moderate radiosensitivity frequently observed in clinic but poorly investigated in the publications and the hyper-radiosensitivity of rare but well-characterized genetic diseases frequently cited in the mechanistic models. This paper makes a comprehensive review of semantic issues, correlations between cellular radiosensitivity and unrepaired DSB, shapes of DSB repair curves, and DSB repair biomarkers in order to propose a new vision of the individual response to IR that would be more coherent with clinical reality

Exploitation du screening pour une reconstruction accélérée en imagerie ultrasonore pour le CND

International audienceDans le contexte du Contrôle Non Destructif (CND), nous proposons d'utiliser une méthode de screening dynamique dans un algorithme d'optimisation en norme ℓ 1 pour accélérer la déconvolution des images ultrasonores formées par faisceaux. Les images étant parcimonieuses, cette technique permet d'éliminer, au cours de l'optimisation, une partie des variables d'optimisation (i.e. des pixels) qui seront de valeur nulle dans la solution finale. Nous testons la méthode proposée pour l'inspection d'un échantillon d'acier qui contient des trous étroitement espacés et de petite taille. Les résultats montrent que le screening élimine jusqu'à 97% des pixels et que l'algorithme de reconstruction gagne jusqu'à un facteur 4 en temps de calcul, sans altérer la reconstruction