Effect of information processing slowness on reading comprehension skills among traumatic brain injured children

Reading abilities can be seriously compromised by a traumatic brain injury (TBI) in childhood. However, only a few researchers have specifically studied these types of abilities following a TBI, leaving nature of reading deficits unclear. This research project examines the influence of speed of information processing, decoding abilities and phonological awareness on reading comprehension deficits among children who sustained a moderate or severe TBI. The performance of a TBI group (n = 27) was compared to the one of 27 control children. This study demonstrated that TBI children present a significantly lower performance on a simple reading comprehension task, compared to children who have never experienced a TBI. Furthermore, the results showed that TBI children are significantly slower in decoding and less efficient in a task involving phonological awareness as compared to non-injured children

Famille et traitement de la toxicomanie chez les adolescents : étude de cas

L’importance d’impliquer la famille dans le traitement de réadaptation en toxicomanie chez les adolescents fait consensus, mais la nature de son influence demeure peu documentée. Objectifs. Le but de cette étude de cas est de mieux comprendre la contribution de l’implication familiale dans ce processus de réadaptation. Méthode. Des entrevues individuelles semi-structurées ont été menées auprès de deux jeunes en traitement de la toxicomanie, leurs parents et les cliniciens les ayant suivis. Des données quantitatives complémentaires pré et post-traitement sur la gravité des problèmes familiaux et de consommation auprès de deux jeunes ont été recueillies. Résultats. Les récits de ces différents acteurs soulignent les bienfaits d’une implication parentale constante à travers les différentes étapes du traitement.There is a general consensus as to the importance of involving the family in the rehabilitation treatment of adolescent substance abuse; but there is little documentation as concerns the nature of family influence in this matter. The objective of the present study is to come to a better understanding of how family involvement contributes to the rehabilitation process. The method consists of semi-standardized individual interviews carried out with two youngsters undergoing substance abuse treatment, and with the parents and clinicians monitoring their progress. We have also collected complementary pre- and post-treatment data regarding the seriousness of family difficulties and substance abuse experienced by these two young people. Results. The narratives of these various stakeholders underline the benefits of a constant parental involvement at each stage of the rehabilitation treatment

Évaluation de l'efficacité des mesures du gouvernement fédéral visant à réduire le nonylphénol et ses dérivés éthoxylés

Depuis que le nonylphénol et ses dérivés éthoxylés ont été déclarés toxiques en 2001 en vertu de la Loi canadienne sur la protection de l’environnement (1999), des mesures de réduction de ces substances ont été mises en oeuvre par le gouvernement fédéral dans cinq secteurs d’activités industrielles. Néanmoins, aucun bilan global sur l’efficacité de ces actions n’avait été effectué à ce jour. Une analyse des données existantes de réduction des NP-NPE dans chacun des secteurs industriels ciblés permet d’évaluer le succès des mesures prises et de dégager certaines recommandations qui pourront influencer la suite des actions concernées

Étude de l'EEG quantifié en éveil et en sommeil chez des adolescents présentant un trouble anxieux

Les troubles anxieux sont parmi les troubles psychiatriques les plus souvent diagnostiqués chez les adolescents. Ces troubles sont souvent accompagnés de nombreuses comorbidités, dont des difficultés de sommeil. L’objectif principal de cette thèse est de caractériser l’activité corticale à l’éveil et pendant le sommeil à l’aide de l’EEG quantifié chez une population d’adolescents présentant un trouble anxieux, et de la comparer à un groupe témoin d’adolescents. Dans un second temps, on cherche à savoir si l’activité EEG des patients anxieux corrèle avec différentes mesures cliniques. Deux études permettent de répondre à ces objectifs, une première portant sur l’activité EEG au cours de l’éveil, et une seconde portant sur l’activité EEG au cours du sommeil (SL et SP). La première étude démontre que l’activité EEG des deux groupes ne présente pas de différence à l’EEG le soir. Par contre, le matin, les patients anxieux présentent une activité significativement supérieure à celle des contrôles aux électrodes centrales (0,75-10 Hz et 13-20 Hz) ainsi qu’aux électrodes occipitales (2,5-7,75 Hz). Dans la seconde étude, nous avons analysé l’activité EEG absolue et relative en SL et en SP. Nous avons trouvé une activité absolue significativement supérieure à l’EEG de la région centrale chez les participants du groupe anxieux : en SLP (stades 3 et 4) sur l’ensemble des bandes de fréquence, en stade 2 sur les bandes de fréquence thêta, alpha et beta seulement. Finalement, en SP, les différences sont trouvées en alpha et beta, et non en thêta et delta. Les résultats obtenus à ces deux études suggèrent la présence de mécanismes de synchronisation et de filtrage inadéquats au niveau de la boucle thalamo-corticale, entraînant une hypervigilance du SNC. Quant aux corrélations entre l’activité EEG et les mesures cliniques, les résultats obtenus dans les deux études révèlent que les fréquences lentes (thêta et delta) de l’activité d’éveil le matin corrèlent à la fois avec l’anxiété de trait et d’état et les fréquences rapides (Alpha et Beta) de l’EEG du sommeil corrèlent sélectivement avec l’anxiété d’état. Il semble donc exister un lien entre les mesures cliniques et l’activité EEG. Une hausse d’activité EEG pourrait être un indicateur de la sévérité accrue des symptômes anxieux.Anxiety disorders are among the most diagnosed psychiatric disorders in the adolescent population. These disorders are often accompanied by different comorbidities, such as sleep problems. The main objective of this thesis is to characterize the cortical activity during wake and sleep, using quantified EEG, in a population of adolescents presenting an anxiety disorder, and to compare these results to those of a control group of adolescents. Secondly, we wish to verify if the EEG activity of the anxious participants correlates with different clinical measures. Two different studies are conducted in order to attain our objectives, the first one being on the EEG activity during wake, and the second being on the EEG activity during sleep (slow wave sleep and rapid eye movement sleep). The first study reveals that the EEG activity from both groups does not differ in the evening. However, in the morning, anxious participants display an increased activity on central electrodes (0.75-10 Hz and 13-20 Hz), and on occipital electrodes (2.5-7.75 Hz). In the second study, we demonstrate that anxious participants show an increased absolute EEG activity on central electrodes: in slow wave sleep (stages 3 and 4), it is found on all frequency bands, in stage 2, it is found on the theta, alpha and beta frequency bands. Finally, in rapid eye movement sleep, the differences are only in alpha and beta, and not in theta and delta. These data suggest the impairment of thalamo-cortical gating mechanisms in adolescents with anxiety disorders, leading to CNS hyperarousal. As for the correlations between the EEG activity and the clinical measures, the results from our studies reveal that the slow frequencies (theta and delta) of morning wake EEG correlate with both trait and state anxiety, while fast frequencies (alpha and beta) from the sleep EEG correlate specifically with state anxiety. Thus, there appears to be an association between EEG activity and clinical measures. An increased EEG activity could be an indicator of the severity of the anxious symptoms

Economic instruments for biodiversity conservation

Biodiversity loss has become a global concern. We now realise that biodiversity directly affects our well-being, providing various services (esthetical values, goods, fibres, spiritual, regulation of climate, of illnesses, of air and water quality, protection against erosion, etc.). However, biodiversity is now eroding at an alarming rate and habitat loss/conversion, climate change, nutrient loading, surexploitation, and invasive species have been identified as the main causes of this increasingly rapid biodiversity loss. One reason why biodiversity loss is still widespread is that markets generally fail to incorporate the total value associated to biodiversity (especially non-market values), which generates externalities and lead to what is known as market distortions. This will often lead to unsustainable practices and discourage long term investments favouring natural resources conservation. With the internalisation of all externalities, the market can achieve its role and allocate resources efficiently. This can be done using economic instruments. Among the economic tools that can be used in biodiversity-related issues there is establishing property rights, market creation and enhancement, charges, fiscal instruments, financial assistance, liability systems and environmental funds. Economic instruments have the potential to induce changes in behaviour in a cost-effective manner, they are also flexible tools that are recognized to increase the efficiency of environmental management, they generate financial resources, create incentives for investments, and stimulate private agents to engage in environmental protection. Although economic instruments can be effective and flexible mechanisms, strong limitations have been identified for their application in developing countries. Among these constraints there are problems linked to the difficulty of valuing biodiversity, institutional constraints, lack of inclusion of local communities, ideological resistance, administrative complexity and limited application in the context of threatened species. Although transfer of technological and financial support could help to resolve some institutional problems, other problems such as corruption can be much more difficult to address. The challenge is thus to develop an integrated strategy that includes short-term direct conservation actions with longer term strategies oriented toward sustainable development. If one takes a look at the specific case of the north-eastern Brazilian Atlantic forest, biodiversity conservation represents a major challenge. Effectively, the original cover has been reduced to 2% due to forest conversion for sugarcane production and forest lies on the private lands of sugarcane companies. Protection of biodiversity and associated ecosystem services thus require commitment of commodity producers, as well as direct investments in conservation. Economical instruments can be used to incite private companies to engage in conservation activities. Examples of how economic instruments could be used include environmental certification and eco-labelling of companies engaging in conservation projects, charge schemes such as pesticide and fertilizer charges, tax deductions offered to companies that engage into reforestation or conservation activities, etc. Although application of economic tools can be strongly limited by institutional factors, they have a strong potential to stimulate conservation actions. Perhaps, economic instruments must thus be implemented as part of a global strategy that will include both short-term direct actions and longer term initiatives. This would include educational programs, economic instruments, and direct payments into a comprehensive strategy we would also work at reinforcing institutional frameworks

Electrophysiologic characteristics of cells spanning the left ventricular wall of human heart: Evidence for presence of M cells

Objectives.The present work was designed to provide an initial characterization of M cells in the normal human heart.Background.Recent studies have uncovered a unique population of cells in the midmyocardial region of the canine ventricle. These cells, named M cells, were found to possess electrophysiologic features and a pharmacologic responsiveness different from those of other myocardial cells. Although well characterized in the dog, their presence or absence in the human heart is unknown.Methods.Standard microelectrode techniques were used to map slices of ventricular free wall obtained from normal human hearts (n = 4). Preparations were paced at cycle lengths ranging from 1 to 10 s.Results.We identified three cell subtypes: endocardial, subepicardial (M cells) and epicardial cells. The principal features differentiating M cells from the other cell subtypes were their longer action potential duration, more accentuated action potential duration rate relations and greater maximal rate of increase in action potential upstroke (Vmax). Our findings suggest that M cells represent ∼ 30% of the cellular mass of the left ventricular wall. Concordance between changes in their repolarization and changes in QTU interval provide support for the role of M cells in the generation of the electrocardiographic (ECG) U wave.Conclusions.This study provides evidence for the existence of M cells in the human heart that contribute to heterogeneity of repolarization within the ventricular wall. Our findings provide strong support for the hypothesis that M cells contribute importantly to the manifestation of the U wave on the ECG

A mutation in the Icsbp1 gene causes susceptibility to infection and a chronic myeloid leukemia–like syndrome in BXH-2 mice

BXH-2 mice develop a fatal myeloid leukemia by a two-step mutagenic process. First, a BXH-2–specific recessive mutation causes a myeloproliferative syndrome. Second, retroviral insertions alter oncogenes or tumor suppressors, resulting in clonal expansion of leukemic cells. We have identified a recessive locus on chromosome 8 (Myls) that is responsible for myeloproliferation in BXH-2. This Myls interval has been narrowed down to 2 Mb and found to contain several positional candidates, including the interferon consensus sequence–binding protein 1 gene (Icsbp, also known as interferon regulatory factor 8 [IRF8]). We show that BXH-2 mice carry a mutation (915 C to T) resulting in an arginine-to-cysteine substitution at position 294 within the predicted IRF association domain of the protein. Although expression of Icsbp1 mRNA transcripts is normal in BXH-2 splenocytes, these cells are unable to produce interleukin 12 and interferon-γ in response to activating stimuli, confirming that R294C behaves as a loss-of-function mutation. Myeloproliferation in BXH-2 mice is concomitant to increased susceptibility to Mycobacterium bovis (BCG) despite the presence of resistance alleles at the Nramp1 locus. These results suggest a two-step model for chronic myeloid leukemia in BXH-2, in which inactivation of Icsbp1 predisposes to myeloproliferation and immunodeficiency. This event is required for retroviral replication, and subsequent insertional mutagenesis that causes leukemia in BXH-2 mice

Thyroid hormone receptor {beta} (TR{beta}) and liver X receptor (LXR) regulate carbohydrate response element binding protein (ChREBP) expression in a tissue selective manner.

Thyroid hormone- (TR) and Liver X- (LXR)receptors are transcription factors involved in lipogenesis. Both receptors recognize the same consensus DNA response element in vitro. It was previously shown that their signalling pathways interact in the control of cholesterol elimination in the liver. In the present study ChREBP, a major transcription factor controlling the activation of glucose-induced lipogenesis in liver, is characterized as a direct target of thyroid hormones(TH) in liver and white adipose tissue(WAT), the two main lipogenic tissues in mice. Using genetic and molecular approaches ChREBP is shown to be specifically regulated by TRbeta, but not by TRalpha in vivo even in WAT where both TR isoforms are expressed. However this isotype specificity is not found in vitro. This TRbeta specific regulation correlates with the loss of TH-induced lipogenesis in TRbeta-/- mice. Fasting/refeeding experiments show that TRbeta is not required for the activation of ChREBP expression particularly marked in WAT following refeeding. However TH can stimulate ChREBP expression in WAT even under fasting conditions suggesting completely independent pathways. Since ChREBP has been described as an LXR target, the interaction of LXR and TRbeta in ChREBP regulation was assayed both in vitro and in vivo. Each receptor recognizes a different response element on the ChREBP promoter, located only eight base pairs apart.There is a crosstalk between LXR and TRbeta signalling on the ChREBP promoter in liver but not in WAT where LXR does not regulate ChREBP expression. The molecular basis for this crosstalk has been determined in in vitro systems

Test-retest reliability of diffusion measures extracted along white matter language fiber bundles using HARDI-based tractography

High angular resolution diffusion imaging (HARDI)-based tractography has been increasingly used in longitudinal studies on white matter macro- and micro-structural changes in the language network during language acquisition and in language impairments. However, test-retest reliability measurements are essential to ascertain that the longitudinal variations observed are not related to data processing. The aims of this study were to determine the reproducibility of the reconstruction of major white matter fiber bundles of the language network using anatomically constrained probabilistic tractography with constrained spherical deconvolution based on HARDI data, as well as to assess the test-retest reliability of diffusion measures extracted along them. Eighteen right-handed participants were scanned twice, one week apart. The arcuate, inferior longitudinal, inferior fronto-occipital, and uncinate fasciculi were reconstructed in the left and right hemispheres and the following diffusion measures were extracted along each tract: fractional anisotropy, mean, axial, and radial diffusivity, number of fiber orientations, mean length of streamlines, and volume. All fiber bundles showed good morphological overlap between the two scanning timepoints and the test-retest reliability of all diffusion measures in most fiber bundles was good to excellent. We thus propose a fairly simple, but robust, HARDI-based tractography pipeline reliable for the longitudinal study of white matter language fiber bundles, which increases its potential applicability to research on the neurobiological mechanisms supporting language

Thyroid hormone receptors are required for the melatonin-dependent control of Rfrp gene expression in mice.

Mammals adapt to seasons using a neuroendocrine calendar defined by the photoperiodic change in the nighttime melatonin production. Under short photoperiod, melatonin inhibits the pars tuberalis production of TSHβ, which, in turn, acts on tanycytes to regulate the deiodinase 2/3 balance resulting in a finely tuned seasonal control of the intra-hypothalamic thyroid hormone T3. Despite the pivotal role of this T3 signaling for synchronizing reproduction with the seasons, T3 cellular targets remain unknown. One candidate is a population of hypothalamic neurons expressing Rfrp, the gene encoding the RFRP-3 peptide, thought to be integral for modulating rodent's seasonal reproduction. Here we show that nighttime melatonin supplementation in the drinking water of melatonin-deficient C57BL/6J mice mimics photoperiodic variations in the expression of the genes Tshb, Dio2, Dio3, and Rfrp, as observed in melatonin-proficient mammals. Notably, we report that this melatonin regulation of Rfrp expression is no longer observed in mice carrying a global mutation of the T3 receptor, TRα, but is conserved in mice with a selective neuronal mutation of TRα. In line with this observation, we find that TRα is widely expressed in the tanycytes. Altogether, our data demonstrate that the melatonin-driven T3 signal regulates RFRP-3 neurons through non-neuronal, possibly tanycytic, TRα.journal article2020 Aug 102020 08 10importe