ECOBES

Jonquière, Canada
Jonquière, Canada
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Gagnon C.,Université de Sherbrooke | Chouinard M.C.,University of Quebec at Chicoutimi | Laberge L.,Ecobes | Laberge L.,University of Quebec at Chicoutimi | And 10 more authors.
Neuromuscular Disorders | Year: 2010

The complexity and variability of disease manifestations in myotonic dystrophy (DM1) pose a challenge for the clinical management of patients. The follow-up of DM1 patients has been described as fragmented, inadequate or even deficient for many patients. Through a systematic review of the medical and social literature and a validation process with a DM1 expert panel, we summarized systemic and social concerns clinically relevant to DM1 and revisited recommendations for treatment. This article summarizes common manifestations of the central nervous system, visual, respiratory, cardiac, gastro-intestinal, genito-urinary, muscular and metabolic impairments. In addition, we emphasized the social features of DM1 such as low education attainment, low employment, poor familial and social environment and poor social participation. While cardiac, respiratory and swallowing problems affect life expectancy, it is often excessive daytime sleepiness, fatigue, gastro-intestinal and cognitive behavioural manifestations that are the most disabling features of the disorder. A more holistic approach in the management of DM1 and a purposeful integrated organization of care involving all members of the patients' environment including family, clinicians, decision-makers and community organizations are needed to move out of the spiral of disease and handicap and move toward optimal citizenship and quality of life. © 2010 Elsevier B.V.


Ken L.W.K.,University of Toronto | Abrahamowicz M.,McGill University | Leonard G.T.,Montreal Neurological Institute | Reischl E.,University of Quebec at Chicoutimi | And 8 more authors.
Journal of Psychiatry and Neuroscience | Year: 2015

Background: Preference for fatty foods is a risk factor for obesity. It is a complex behaviour that involves the brain reward system and is regulated by genetic and environmental factors, such as the opioid receptor mu-1 gene (OPRM1) and prenatal exposure to maternal cigarette smoking (PEMCS). We examined whether OPRM1 and PEMCS interact in influencing fat intake and whether exposure-­ associated epigenetic modifications of OPRM1 may mediate this gene-environment interaction. Methods: We studied adolescents from a French Canadian genetic founder population, half of whom were exposed prenatally to maternal cigarette smoking. Fat intake was assessed with a 24-hour food recall in the form of a structured interview conducted by a trained nutritionist. The OPRM1 variant rs2281617 was genotyped for the whole sample with the Illumina Human610-Quad and HumanOmniExpress BeadChips. Methylation of blood DNA was assessed at 21 CpGs across OPRM1 in a subset of the sample using the Illumina HumanMethylation450 BeadChip. Results: We included 956 adolescents in our study. In the whole sample, OPRM1 (T carrier in rs2281617) was associated with lower fat intake (-1.6%, p = 0.017), and PEMCS was associated with higher fat intake (+1.6%, p = 0.005). OPRM1 and PEMCS interacted with each other (p = 0.003); the “protective” (fat intake-lowering) allele of OPRM1 was associated with lower fat intake in nonexposed (-3.2%, p < 0.001) but not in exposed individuals (+0.8%, p = 0.42). Further, PEMCS was associated with lower DNA methylation across multiple CpGs across OPRM1 in exposed versus nonexposed individuals (p = 0.031). Limitations: A limitation of our study was its cross-­ sectional design. Conclusion: Our study suggests that PEMCS may interact with OPRM1 in increasing fat preference. Silencing of the protective OPRM1 allele in exposed adolescents might be related to epigenetic modification of this gene. © 2015 8872147 Canada Inc. or its licensors.


Mareckova K.,Rotman Research Institute | Mareckova K.,University of Nottingham | Mareckova K.,Masaryk University | Chakravarty M.M.,Rotman Research Institute | And 16 more authors.
Brain Structure and Function | Year: 2015

We used magnetic resonance (MR) images obtained in same-sex and opposite-sex dizygotic twins (n = 119, 8 years of age) to study possible effects of prenatal androgens on craniofacial features. Using a principal component analysis of 19 craniofacial landmarks placed on the MR images, we identified a principal component capturing craniofacial features that distinguished females with a presumed differential exposure to prenatal androgens by virtue of having a male (vs. a female) co-twin (Cohen’s d = 0.76). Subsequently, we tested the possibility that this craniofacial “signature” of prenatal exposure to androgens predicts brain size, a known sexually dimorphic trait. In an independent sample of female adolescents (singletons; n = 462), we found that the facial signature predicts up to 8 % of variance in brain size. These findings are consistent with the organizational effects of androgens on brain development and suggest that the facial signature derived in this study could complement other indirect measures of prenatal exposure to androgens. © 2014, Springer-Verlag Berlin Heidelberg.


Wong A.P.Y.,University of Toronto | Wong A.P.Y.,Rotman Research Institute | Pipitone J.,Kimel Family Translational Imaging Genetics Research Laboratory | Park M.T.M.,Kimel Family Translational Imaging Genetics Research Laboratory | And 14 more authors.
NeuroImage | Year: 2014

The pituitary gland is a key structure in the hypothalamic-pituitary-gonadal (HPG) axis - it plays an important role in sexual maturation during puberty. Despite its small size, its volume can be quantified using magnetic resonance imaging (MRI). Here, we study a cohort of 962 typically developing adolescents from the Saguenay Youth Study and estimate pituitary volumes using a newly developed multi-atlas segmentation method known as the MAGeT Brain algorithm. We found that age and puberty stage (controlled for age) each predicts adjusted pituitary volumes (controlled for total brain volume) in both males and females. Controlling for the effects of age and puberty stage, total testosterone and estradiol levels also predict adjusted pituitary volumes in males and pre-menarche females, respectively. These findings demonstrate that the pituitary gland grows during adolescence, and its volume relates to circulating plasma-levels of sex steroids in both males and females. © 2014 Elsevier Inc.


Markova D.,Rotman Research Institute | Markova D.,Maastricht University | Richer L.,University of Quebec at Chicoutimi | Pangelinan M.,Rotman Research Institute | And 10 more authors.
Hormones and Behavior | Year: 2016

Distinct differences in the human voice emerge during adolescence, with males producing deeper and more resonant voices than females by the end of sexual maturation. Using magnetic resonance images of heads and voice recordings obtained in 532 typically developing adolescents, we investigate what might be the drivers of this change in voice, and the subjective judgment of the voice "maleness" and "femaleness".We show clear sex differences in the morphology of voice-related structures during adolescence, with males displaying strong associations between age (and puberty) and both vocal-fold and vocal-tract length; this was not the case in female adolescents. At the same time, males (compared with females) display stronger associations between age (and puberty) with both fundamental frequency and formant position. In males, vocal morphology was a mediator in the relationship between bioavailable testosterone and acoustic indices.Subjective judgment of the voice sex could be predicted by the morphological and acoustic parameters in males only: the length of vocal folds and its acoustic counterpart, fundamental frequency, is a larger predictor of subjective "maleness" of a voice than vocal-tract length and formant position. © 2016 Elsevier Inc.


Chakravarty M.M.,Rotman Research Institute | Chakravarty M.M.,The Hospital for Sick Children | Aleong R.,Rotman Research Institute | Leonard G.,Montreal Neurological Institute | And 12 more authors.
PLoS ONE | Year: 2011

Quantitative analysis of craniofacial morphology is of interest to scholars working in a wide variety of disciplines, such as anthropology, developmental biology, and medicine. T1-weighted (anatomical) magnetic resonance images (MRI) provide excellent contrast between soft tissues. Given its three-dimensional nature, MRI represents an ideal imaging modality for the analysis of craniofacial structure in living individuals. Here we describe how T1-weighted MR images, acquired to examine brain anatomy, can also be used to analyze facial features. Using a sample of typically developing adolescents from the Saguenay Youth Study (N = 597; 292 male, 305 female, ages: 12 to 18 years), we quantified inter-individual variations in craniofacial structure in two ways. First, we adapted existing nonlinear registration-based morphological techniques to generate iteratively a group-wise population average of craniofacial features. The nonlinear transformations were used to map the craniofacial structure of each individual to the population average. Using voxel-wise measures of expansion and contraction, we then examined the effects of sex and age on inter-individual variations in facial features. Second, we employed a landmark-based approach to quantify variations in face surfaces. This approach involves: (a) placing 56 landmarks (forehead, nose, lips, jaw-line, cheekbones, and eyes) on a surface representation of the MRI-based group average; (b) warping the landmarks to the individual faces using the inverse nonlinear transformation estimated for each person; and (3) using a principal components analysis (PCA) of the warped landmarks to identify facial features (i.e. clusters of landmarks) that vary in our sample in a correlated fashion. As with the voxel-wise analysis of the deformation fields, we examined the effects of sex and age on the PCA-derived spatial relationships between facial features. Both methods demonstrated significant sexual dimorphism in craniofacial structure in areas such as the chin, mandible, lips, and nose. © 2011 Chakravarty et al.


Mareckova K.,Rotman Research Institute | Mareckova K.,University of Nottingham | Weinbrand Z.,Rotman Research Institute | Chakravarty M.M.,Rotman Research Institute | And 14 more authors.
Hormones and Behavior | Year: 2011

Sex identification of a face is essential for social cognition. Still, perceptual cues indicating the sex of a face, and mechanisms underlying their development, remain poorly understood. Previously, our group described objective age- and sex-related differences in faces of healthy male and female adolescents (12-18 years of age), as derived from magnetic resonance images (MRIs) of the adolescents' heads. In this study, we presented these adolescent faces to 60 female raters to determine which facial features most reliably predicted subjective sex identification. Identification accuracy correlated highly with specific MRI-derived facial features (e.g. broader forehead, chin, jaw, and nose). Facial features that most reliably cued male identity were associated with plasma levels of testosterone (above and beyond age). Perceptible sex differences in face shape are thus associated with specific facial features whose emergence may be, in part, driven by testosterone. © 2011 Elsevier Inc.


Pangelinan M.M.,Rotman Research Institute | Leonard G.,Montreal Neurological Institute | Perron M.,ECOBES | Perron M.,University of Quebec at Chicoutimi | And 7 more authors.
Brain Structure and Function | Year: 2016

Some of the known sex differences in white matter emerge during adolescence. Here, we replicate and extend our previous findings of sex differences in the structure of the corticospinal tract (Perrin et al. 2009; Hervé et al. 2009). In a large normative sample of adolescents, we observed age × sex interactions in the signal intensity of T1-weighted (T1W) images (n = 941) and in magnetization transfer ratio (MTR; n = 761); both features were inversely associated with age in males but not in females. Moreover, we hypothesized that the age-related differences in CST structure exhibited by males would be mediated by differences in puberty stage and levels of bioavailable testosterone. We confirmed this prediction using mediation analysis with bootstrapping. These findings suggest that sex differences in the CST structure observed during male adolescence may be due to multiple processes associated with puberty, including (but not limited to) the rising levels of testosterone. © 2014, Springer-Verlag Berlin Heidelberg.


PubMed | University of Calgary, University of Quebec at Chicoutimi, The Hospital of Sick Children, Rotman Research Institute and 2 more.
Type: Journal Article | Journal: Brain structure & function | Year: 2016

Some of the known sex differences in white matter emerge during adolescence. Here, we replicate and extend our previous findings of sex differences in the structure of the corticospinal tract (Perrin et al. 2009; Herv et al. 2009). In a large normative sample of adolescents, we observed agesex interactions in the signal intensity of T1-weighted (T1W) images (n=941) and in magnetization transfer ratio (MTR; n=761); both features were inversely associated with age in males but not in females. Moreover, we hypothesized that the age-related differences in CST structure exhibited by males would be mediated by differences in puberty stage and levels of bioavailable testosterone. We confirmed this prediction using mediation analysis with bootstrapping. These findings suggest that sex differences in the CST structure observed during male adolescence may be due to multiple processes associated with puberty, including (but not limited to) the rising levels of testosterone.


Melka M.G.,University of Toronto | Abrahamowicz M.,McGill University | Leonard G.T.,Montreal Neurological Institute | Perron M.,ECOBES | And 7 more authors.
PLoS ONE | Year: 2013

Visceral fat (VF) promotes the development of metabolic syndrome (MetS), which emerges as early as in adolescence. The clustering of MetS components suggests shared etiologies, but these are largely unknown and may vary between males and females. Here, we investigated the latent structure of pre-clinical MetS in a community-based sample of 286 male and 312 female adolescents, assessing their abdominal adiposity (VF) directly with magnetic resonance imaging. Principal component analysis of the five MetS-defining variables (VF, blood pressure [BP], fasting serum triglycerides, HDL-cholesterol and glucose) identified two independent components in both males and females. The first component was sex-similar; it explained >30% of variance and was loaded by all but BP variables. The second component explained >20% of variance; it was loaded by BP similarly in both sexes but additional loading by metabolic variables was sex-specific. This sex-specificity was not detected in analyses that used waist circumference instead of VF. In adolescence, MetS-defining variables cluster into at least two sub-syndromes: (1) sex-similar metabolic abnormalities of obesity-induced insulin resistance and (2) sex-specific metabolic abnormalities associated with BP elevation. These results suggest that the etiology of MetS may involve more than one pathway and that some of the pathways may differ between males and females. Further, the sex-specific metabolic abnormalities associated with BP elevation suggest the need for sex-specific prevention and treatment strategies of MetS. © 2013 Melka et al.

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