Nouveaux aspects de la prise en charge de l'hypertension artérielle chez le patient insuffisant rénal chronique [New aspects of hypertension management in patients with chronic kidney disease].

Hypertension is a frequent finding in patients with chronic kidney disease. Whether primary or secondary to renal disease, hypertension remains an important risk factory for the progression of chronic kidney disease and the occurrence of cardiovascular events. The objective of this paper is to review different treatment strategies in hypertensive CKD patients, with the exclusion of patients with renal replacement therapy such as dialysis or renal transplantation.

Magnetoencephalography demonstrates multiple asynchronous generators during human sleep spindles.

Sleep spindles are approximately 1 s bursts of 10-16 Hz activity that occur during stage 2 sleep. Spindles are highly synchronous across the cortex and thalamus in animals, and across the scalp in humans, implying correspondingly widespread and synchronized cortical generators. However, prior studies have noted occasional dissociations of the magnetoencephalogram (MEG) from the EEG during spindles, although detailed studies of this phenomenon have been lacking. We systematically compared high-density MEG and EEG recordings during naturally occurring spindles in healthy humans. As expected, EEG was highly coherent across the scalp, with consistent topography across spindles. In contrast, the simultaneously recorded MEG was not synchronous, but varied strongly in amplitude and phase across locations and spindles. Overall, average coherence between pairs of EEG sensors was approximately 0.7, whereas MEG coherence was approximately 0.3 during spindles. Whereas 2 principle components explained approximately 50% of EEG spindle variance, >15 were required for MEG. Each PCA component for MEG typically involved several widely distributed locations, which were relatively coherent with each other. These results show that, in contrast to current models based on animal experiments, multiple asynchronous neural generators are active during normal human sleep spindles and are visible to MEG. It is possible that these multiple sources may overlap sufficiently in different EEG sensors to appear synchronous. Alternatively, EEG recordings may reflect diffusely distributed synchronous generators that are less visible to MEG. An intriguing possibility is that MEG preferentially records from the focal core thalamocortical system during spindles, and EEG from the distributed matrix system.

PAX5 activates the transcription of the human telomerase reverse transcriptase gene in B cells.

Telomerase is an RNA-dependent DNA polymerase that synthesizes telomeric DNA. Its activity is not detectable in most somatic cells but it is reactivated during tumorigenesis. In most cancers, the combination of hTERT hypermethylation and hypomethylation of a short promoter region is permissive for low-level hTERT transcription. Activated and malignant lymphocytes express high telomerase activity, through a mechanism that seems methylation-independent. The aim of this study was to determine which mechanism is involved in the enhanced expression of hTERT in lymphoid cells. Our data confirm that in B cells, some T cell lymphomas and non-neoplastic lymph nodes, the hTERT promoter is unmethylated. Binding sites for the B cell-specific transcription factor PAX5 were identified downstream of the ATG translational start site through EMSA and ChIP experiments. ChIP assays indicated that the transcriptional activation of hTERT by PAX5 does not involve repression of CTCF binding. In a B cell lymphoma cell line, siRNA-induced knockdown of PAX5 expression repressed hTERT transcription. Moreover, ectopic expression of PAX5 in a telomerase-negative normal fibroblast cell line was found to be sufficient to activate hTERT expression. These data show that activation of hTERT in telomerase-positive B cells is due to a methylation-independent mechanism in which PAX5 plays an important role.

Polychlorinated and polybrominated biphenyls

This volume of the IARC Monographs provides evaluations of the carcinogenicity of polychlorinated biphenyls and polybrominated biphenyls. Polychlorinated biphenyls are a class of aromatic compounds comprising 209 congeners, each containing 1 to 10 chlorine atoms attached to a biphenyl nucleus. Technical products, which were manufactured to obtain a certain degree of chlorination, are mixtures of numerous congeners. These products were widely used as dielectric fluid in capacitors and transformers, and to a lesser extent in building materials. Although their production and use has been banned in most countries, these compounds are ubiquitous environmental pollutants, including in polar regions and the deep ocean, because they are persistent and bioaccumulate. Worldwide monitoring programmes have shown that polychlorinated biphenyls are present in most samples of human milk. An IARC Monographs Working Group reviewed epidemiological evidence, animal bioassays, and mechanistic and other relevant data to reach conclusions as to the carcinogenic hazard to humans of polychlorinated biphenyls, of the subclass of dioxinlike polychlorinated biphenyls, and of polybrominated biphenyls.

Transient detectable viremia and the risk of viral rebound in patients from the Swiss HIV Cohort Study.

BACKGROUND: Temporary increases in plasma HIV RNA ('blips') are common in HIV patients on combination antiretroviral therapy (cART). Blips above 500 copies/mL have been associated with subsequent viral rebound. It is not clear if this relationship still holds when measurements are made using newer more sensitive assays. METHODS: We selected antiretroviral-naive patients that then recorded one or more episodes of viral suppression on cART with HIV RNA measurements made using more sensitive assays (lower limit of detection below 50 copies/ml). We estimated the association in these episodes between blip magnitude and the time to viral rebound. RESULTS: Four thousand ninety-four patients recorded a first episode of viral suppression on cART using more sensitive assays; 1672 patients recorded at least one subsequent suppression episode. Most suppression episodes (87 %) were recorded with TaqMan version 1 or 2 assays. Of the 2035 blips recorded, 84 %, 12 % and 4 % were of low (50-199 copies/mL), medium (200-499 copies/mL) and high (500-999 copies/mL) magnitude respectively. The risk of viral rebound increased as blip magnitude increased with hazard ratios of 1.20 (95 % CI 0.89-1.61), 1.42 (95 % CI 0.96-2.19) and 1.93 (95 % CI 1.24-3.01) for low, medium and high magnitude blips respectively; an increase of hazard ratio 1.09 (95 % CI 1.03 to 1.15) per 100 copies/mL of HIV RNA. CONCLUSIONS: With the more sensitive assays now commonly used for monitoring patients, blips above 200 copies/mL are increasingly likely to lead to viral rebound and should prompt a discussion about adherence.

Reliability and validity of nonverbal thin slices in social interactions

Four studies investigated the reliability and validity of thin slices of nonverbal behavior from social interactions including (1) how well individual slices of a given behavior predict other slices in the same interaction; (2) how well a slice of a given behavior represents the entirety of that behavior within an interaction; (3) how long a slice is necessary to sufficiently represent the entirety of a behavior within an interaction; (4) which slices best capture the entirety of behavior, across different behaviors; and (5) which behaviors (of six measured behaviors) are best captured by slices. Notable findings included strong reliability and validity for thin slices of gaze and nods, and that a 1.5 min slice from the start of an interaction may adequately represent some behaviors. Results provide useful information to researchers making decisions about slice measurement of behavior.

Risk factors of postictal generalized EEG suppression in generalized convulsive seizures.

OBJECTIVE: To identify the clinical determinants of occurrence of postictal generalized EEG suppression (PGES) after generalized convulsive seizures (GCS). METHODS: We reviewed the video-EEG recordings of 417 patients included in the REPO2MSE study, a multicenter prospective cohort study of patients with drug-resistant focal epilepsy. According to ictal semiology, we classified GCS into 3 types: tonic-clonic GCS with bilateral and symmetric tonic arm extension (type 1), clonic GCS without tonic arm extension or flexion (type 2), and GCS with unilateral or asymmetric tonic arm extension or flexion (type 3). Association between PGES and person-specific or seizure-specific variables was analyzed after correction for individual effects and the varying number of seizures. RESULTS: A total of 99 GCS in 69 patients were included. Occurrence of PGES was independently associated with GCS type (p < 0.001) and lack of early administration of oxygen (p < 0.001). Odds ratio (OR) for GCS type 1 in comparison with GCS type 2 was 66.0 (95% confidence interval [CI 5.4-801.6]). In GCS type 1, risk of PGES was significantly increased when the seizure occurred during sleep (OR 5.0, 95% CI 1.2-20.9) and when oxygen was not administered early (OR 13.4, 95% CI 3.2-55.9). CONCLUSION: The risk of PGES dramatically varied as a function of GCS semiologic characteristics. Whatever the type of GCS, occurrence of PGES was prevented by early administration of oxygen.

Les paradoxes de l'argumentation en contexte d'éducation : s'accorder sur les désaccords. Analyse d'interactions argumentatives dans un dispositif de formation en psychologie à l'Université

Dans le chapitre « Les paradoxes de l'argumentation en contexte d'éducation: s'accorder sur les désaccords », Muller Mirza part de l'idée qu'à la différence des situations ordinaires de désaccords, les dispositifs utilisant l'argumentation dans des contextes d'éducation demandent aux participants précisément de résoudre ces désaccords. Leur sont donc interdites, par contrat plus ou moins implicite, les échappatoires auxquelles nous recourons volontiers dans les discours quotidiens qui permettent d'éviter de problématiser la question en discussion. C'est dire qu'elle aborde directement une difficulté souvent signalée dans les études sur l'argumentation en contexte éducatif : la tension entre d'une part l'expression de points de vue différents, étape nécessaire à la construction des connaissances, et d'autre part la préservation de la relation entre les interlocuteurs, de leurs faces. Le chapitre propose comme objet de discussion le rôle de cette tension dans des situations d'apprentissage en analysant des productions argumentatives réalisées dans le cadre d'un dispositif particulier. Il invite ainsi à une réflexion non seulement sur les ingrédients des dispositifs pédagogiques qui permettraient de prendre en compte cette tension mais aussi sur les méthodes d'analyse des interactions argumentatives. L'étude de cas met en scène des étudiants de master en psychologie sociale, dans le cadre d'un jeu de rôle : ils sont placés dans la perspective de leur futur métier, et figurent des psychologues conseillant des éducateurs face à des jeunes qui utilisent des insultes racistes entre eux. Le dispositif mis en oeuvre satisfait quatre exigences d'ordre théorique, favorables selon l'auteure à une bonne résolution des désaccords : le ménagement des faces des interlocuteurs en fixant des rôles ne correspondant pas nécessairement aux positions de chacun ; la construction de connaissances,préalable à la discussion ; la médiation de l'échange par un outil, ici un « chat », qui permet d'échanger les points de vue et d'apporter une dimension réflexive en cours d'interaction sur les points de vue exprimés ; le fait de donner du sens à l'activité, en simulant une situation professionnelle potentielle. L'analyse des échanges a été réalisée sur onze corpus constitués par les étudiants en petits groupes de trois ou quatre travaillant sur un logiciel de « chat ». Les questions abordées étaient les suivantes : Comment les interlocuteurs négocient-ils les désaccords qui apparaissent au cours des échanges? Ces désaccords sont-ils propices à une problématisation? Les participants mettent-ils en oeuvre des dynamiques d'« exploration » du désaccord relevé? Cette analyse, inspirée d'une approche socioculturelle reprise en partie des travaux de Neil Mercer sur les « discours exploratoires », met en évidence des dynamiques argumentatives de qualité au cours desquels les désaccords sont non seulement exprimés mais également problématisés au sein des groupes. Elle met entre autres en évidence que le sens de l'activité pour les étudiants est en partie tributaire d'un contrat didactique et pédagogique : leurs échanges sont la base de leur évaluation universitaire. Néanmoins la similitude entre situation d'enseignement et situation professionnelle a largement été perçue par les étudiants et motivante pour eux, ce qui a certainement concouru également à la qualité des échanges.