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.

What’s New in Limb Lengthening and Deformity Correction

Abstract: This update summarizes select articles pertaining to limb lengthening and deformity correction that were published between January 1, 2014, and December 31, 2014. ### Guided Growth Angular deformities in growing children can often be corrected with use of guided growth. Although two-hole 3.5-mm reconstruction plates with 4-mm cancellous screws provide an economical and effective alternative to design-specific, tension-band plating systems, their 10% screw breakage rate merits consideration of the use of larger (4.5-mm) cortical screws1. Caution must be used when applying medial distal-femoral temporary tension-band plates to prevent impingement or injury to the medial patellofemoral ligament2. Despite more implant-related complications, medial malleolar transphyseal screws in comparison with tension-band plates can result in faster corrections3. Ankle valgus in children with spina bifida can be effectively corrected with the use of a medial malleolar screw4. Following guided growth treatment, physical therapy readily resolves the delayed return to function that most commonly occurs in children who are older than eleven years of age and in patients who are undergoing bilateral procedures, distal femoral plating, or procedures involving four or more implants5. A modified technique for insertion of tension-band plates has decreased operative time and incision size6. Parallel compared with divergent screw configuration was favorable in a synthetic-bone guided-growth model7. Tension-band plates at the trochanteric apophysis may have a role as a non-osteotomy containment strategy for Legg-Calve-Perthes disease8. ### Limb-Length Discrepancy A comparison of lateral elbow and left hand radiographs for assessing skeletal maturity revealed that the elbow radiographs were preferred during the growth spurt and the hand radiographs were more useful following the growth spurt9. When evaluating the effectiveness of percutaneous physeal ablation with a drill and burr technique (the Canale method) compared with that of transphyseal screws (the Metaizeau method), …

The early crying paradox : A modest proposal.

Abstract: In contemporary Western societies, infants in the first 3 months cry more than at any other time during their life. Although this crying is believed to function to assure nutrition, protection, and mother-infant interaction thought to be essential for later attachment, it also predisposes to complaints of excessive crying ("colic"), discontinuing breast-feeding, and, in the extreme case, child abuse. A resolution of this apparent paradox is proposed based on evidence that elements of caregiving are important determinants of some aspects of early crying. It is argued that early human crying under caretaking conditions typical in Western societies is characterized by prolonged crying bouts, that it is specifically the length of crying bouts (rather than frequency or pattern) that is affected by caregiving practice, and that prolonged crying bouts are probably not characteristic with caretaking practices typical in non-Western societies and possibly in our evolutionary past. It is suggested that caregiving behaviors may recruit normal physiological functions that potentiate cry bout duration in Western caregiving contexts, but reduce it in others. Frequent, short bouts are sufficient, and probably better suited than long bouts, to promote all the positive and presumably adaptive functions claimed for infant crying. Furthermore, they may have provided a mechanism by which infants could enhance their own fitness.

Molecular Characterization of Choroid Plexus Tumors Reveals Novel Clinically Relevant Subgroups

Abstract: Purpose To investigate molecular alterations in choroid plexus tumors (CPT) using a genome-wide high-throughput approach to identify diagnostic and prognostic signatures that will refine tumor stratification and guide therapeutic options. Experimental design One hundred CPTs were obtained from a multi-institutional tissue and clinical database. Copy-number (CN), DNA methylation, and gene expression signatures were assessed for 74, 36, and 40 samples, respectively. Molecular subgroups were correlated with clinical parameters and outcomes. Results Unique molecular signatures distinguished choroid plexus carcinomas (CPC) from choroid plexus papillomas (CPP) and atypical choroid plexus papillomas (aCPP); however, no significantly distinct molecular alterations between CPPs and aCPPs were observed. Allele-specific CN analysis of CPCs revealed two novel subgroups according to DNA content: hypodiploid and hyperdiploid CPCs. Hyperdiploid CPCs exhibited recurrent acquired uniparental disomy events. Somatic mutations in TP53 were observed in 60% of CPCs. Investigating the number of mutated copies of p53 per sample revealed a high-risk group of patients with CPC carrying two copies of mutant p53, who exhibited poor 5-year event-free (EFS) and overall survival (OS) compared with patients with CPC carrying one copy of mutant p53 (OS: 14.3%, 95% confidence interval, 0.71%-46.5% vs. 66.7%, 28.2%-87.8%, respectively, P = 0.04; EFS: 0% vs. 44.4%, 13.6%-71.9%, respectively, P = 0.03). CPPs and aCPPs exhibited favorable survival. Discussion Our data demonstrate that differences in CN, gene expression, and DNA methylation signatures distinguish CPCs from CPPs and aCPPs; however, molecular similarities among the papillomas suggest that these two histologic subgroups are indeed a single molecular entity. A greater number of copies of mutated TP53 were significantly associated to increased tumor aggressiveness and a worse survival outcome in CPCs. Collectively, these findings will facilitate stratified approaches to the clinical management of CPTs.

Bovine SNRPN Methylation Imprint in Oocytes and Day 17 In Vitro-Produced and Somatic Cell Nuclear Transfer Embryos

Abstract: Findings from recent studies have suggested that the low survival rate of animals derived via somatic cell nuclear transfer (SCNT) may be in part due to epigenetic abnormalities brought about by this procedure. DNA methylation is an epigenetic modification of DNA that is implicated in the regulation of imprinted genes. Genes subject to genomic imprinting are expressed monoallelically in a parent of origin-dependent manner and are important for embryo growth, placental function, and neurobehavioral processes. The vast majority of imprinted genes have been studied in mice and humans. Herein, our objectives were to characterize the bovine SNRPN gene in gametes and to compare its methylation profile in in vivo-produced, in vitro-produced, and SCNT-derived Day 17 elongating embryos. A CpG island within the 5' region of SNRPN was identified and examined using bisulfite sequencing. SNRPN alleles were unmethylated in sperm, methylated in oocytes, and approximately 50% methylated in somatic samples. The examined SNRPN region appeared for the most part to be normally methylated in three in vivo-produced Day 17 embryos and in eight in vitro-produced Day 17 embryos examined, while alleles from Day 17 SCNT embryos were severely hypomethylated in seven of eight embryos. In this study, we showed that the SNRPN methylation profiles previously observed in mouse and human studies are also conserved in cattle. Moreover, SCNT-derived Day 17 elongating embryos were abnormally hypomethylated compared with in vivo-produced and in vitro-produced embryos, which in turn suggests that SCNT may lead to faulty reprogramming or maintenance of methylation imprints at this locus.

Understanding ischemic retinopathies: emerging concepts from oxygen-induced retinopathy

Abstract: Ischemic retinopathies, such as retinopathy of prematurity and diabetic retinopathy are characterized by an initial microvascular degeneration, followed by an abnormal hypoxia-induced neovascularization. Oxygen-induced retinopathy (OIR) is a well-established in vivo model of ischemic retinopathies, which, although the triggering insult varies, all share a common end result of capillary loss. Understanding the mechanisms of normal retinal vascular development as well as the pathophysiological processes leading to the primary vascular loss is the key to develop treatments to prevent the sight-threatening neovascularization associated with human ischemic retinopathies. The importance of oxygen-dependant vascular endothelial growth factor in the pathophysiology of both phases of OIR has long been recognized. However, recent studies point out that OIR is a multifactorial disease, resulting from additive effects of an unbalanced expression of pro- and anti-angiogenic factors, interrelated with protective effects of nutritional factors and cytotoxic effects of oxidative and nitro-oxidative stress-dependant mediators. This review summarizes the most recent aspects of the research on OIR conducted in our laboratory and others, with a particular focus on the role of new mediators of nitro-oxidative stress, the trans-arachidonic acids, in microvascular degeneration, and on a novel pathway of metabolic signaling where hypoxia-driven succinate, via receptor GPR91, governs normal and pathological retinal angiogenesis.