Montreal Children's Hospital

About: Montreal Children's Hospital is a healthcare organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 3842 authors who have published 4816 publications receiving 200198 citations.

Executive functions and physical aggression after controlling for attention deficit hyperactivity disorder, general memory, and IQ.

Abstract: This study examined the role of ADHD in the association between physical aggression and two types of executive functions. Boys received a cognitive-neuropsychological test battery over the ages of 13, 14, and 15 years. Diagnostic Interview Schedule for Children (DISC 2.25) data were collected from the boys and one parent between ages 14 and 16, and an IQ estimate was obtained at age 15. Three groups, diering in stability and level of physical aggression since kindergarten, were formed: Stable Aggressive, Unstable Aggressive, and Nonaggressive. Composite scores of validated executive function tests of working memory representing subjective ordering and conditional association learning were formed. A MANCOVA (N fl 149) using ADHD status, teacher-rated negative emotionality, general memory abilities, and IQ as covariates was performed on the two composite scores. ADHD and teacher-rated emotionality did not provide significant adjustment to the dependent variables. Number of ADHD symptoms was negatively associated only with general memory and IQ. General memory contributed significantly to adjusting for conditional association test scores. Group dierences indicated lower conditional association scores for Unstable Aggressive boys relative to the other groups. Both IQ and general memory abilities interacted with subjective ordering within the groups. Specifically, Stable Aggressive boys performed poorly on this measure and did not benefit from increases in IQ whereas Nonaggressive boys performed best and were not disadvantaged by lower general memory abilities. This suggests a relationship exists between aspects of working memory and a history of physical aggression regardless of ADHD and IQ.

Molecular Profiling Identifies Prognostic Subgroups of Pediatric Glioblastoma and Shows Increased YB-1 Expression in Tumors

Abstract: Purpose Pediatric glioblastoma (pGBM) is a rare, but devastating brain tumor. In contrast to GBM in adults (aGBM), little is known about the mechanisms underlying its development. Our aim is to gain insight into the molecular pathways of pGBM. Materials and Methods Thirty-two pGBM and seven aGBM samples were investigated using biochemical and transcriptional profiling. Ras and Akt pathway activation was assessed through the phosphorylation of downstream effectors, and gene expression profiles were generated using the University Health Network Human 19K cDNA arrays. Results were validated using real-time polymerase chain reaction and immunohistochemistry and compared with existing data sets on aGBM. Results There are at least two subsets of pGBM. One subset, associated with Ras and Akt pathway activation, has very poor prognosis and exhibits increased expression of genes related to proliferation and to a neural stem-cell phenotype, similar to findings in aggressive aGBM. This subset was still molecularly d...

Potential significance of genomic imprinting defects for reproduction and assisted reproductive technology

Abstract: Recent studies suggest a possible link between human assisted reproductive technology and genomic imprinting disorders. Assisted reproductive technology includes the isolation, handling and culture of gametes and early embryos at times when imprinted genes are likely to be particularly vulnerable to external influences. Evidence of sex-specific differences in imprint acquisition suggests that male and female germ cells may be susceptible to perturbations in imprinted genes at specific prenatal and postnatal stages. Imprints acquired first during gametogenesis must be maintained during preimplantation development when reprogramming of the overall genome occurs. In this review, we will discuss both new developments in our understanding of genomic imprinting including the mechanisms and timing of imprint erasure, acquisition and maintenance during germ cell development and early embryogenesis as well as the implications of this research for future epigenetic studies in reproduction and assisted reproductive technology.

Characterization of Insulin-Like Growth Factor Receptors in Rat Anterior Pituitary, Hypothalamus, and Brain

Abstract: Studies were undertaken to determine whether the insulin-like growth factors (IGF-I and -II), bind to specific membrane receptors in the pituitary and brain. Anterior pituitary glands, hypothalami, and brains (minus hypothalami) were obtained from adult male Sprague-Dawley rats (225–300 g) and 15,000 × g membranes prepared by differential centrifugation. Binding of 125I-IGF-I and 125I-IGF-II to all three membrane preparations was specific, time and temperature dependent, reversible, and increased in proportion to increasing concentrations of membrane protein or labeled ligand. Neither the pH of the assay buffer (6.5–8.5) nor the presence or absence of 1 mg/ml bacitracin had any significant effect on the levels of specific binding. In all three membrane preparations IGF-II specific binding was 3–5 times higher than that observed for IGF-I, and unlabeled IGF-II displaced either 125I-IGF-I or 125I-IGF-II better than comparable concentrations of IGF-I. All three membrane preparations showed similar low specif...