The Child and Family Research Institute

Vancouver, Canada

The Child and Family Research Institute

Vancouver, Canada
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Booth B.G.,Simon Fraser University | Miller S.P.,The Hospital for Sick Children | Miller S.P.,University of British Columbia | Miller S.P.,University of Toronto | And 11 more authors.
NeuroImage | Year: 2016

We introduce the STEAM DTI analysis engine: a whole brain voxel-based analysis technique for the examination of diffusion tensor images (DTIs). Our STEAM analysis technique consists of two parts. First, we introduce a collection of statistical templates that represent the distribution of DTIs for a normative population. These templates include various diffusion measures from the full tensor, to fractional anisotropy, to 12 other tensor features. Second, we propose a voxel-based analysis (VBA) pipeline that is reliable enough to identify areas in individual DTI scans that differ significantly from the normative group represented in the STEAM statistical templates. We identify and justify choices in the VBA pipeline relating to multiple comparison correction, image smoothing, and dealing with non-normally distributed data. Finally, we provide a proof of concept for the utility of STEAM on a cohort of 134 very preterm infants. We generated templates from scans of 55 very preterm infants whose T1 MRI scans show no abnormalities and who have normal neurodevelopmental outcome. The remaining 79 infants were then compared to the templates using our VBA technique. We show: (a) that our statistical templates display the white matter development expected over the modeled time period, and (b) that our VBA results detect abnormalities in the diffusion measurements that relate significantly with both the presence of white matter lesions and with neurodevelopmental outcomes at 18 months. Most notably, we show that STEAM produces personalized results while also being able to highlight abnormalities across the whole brain and at the scale of individual voxels. While we show the value of STEAM on DTI scans from a preterm infant cohort, STEAM can be equally applied to other cohorts as well. To facilitate this whole-brain personalized DTI analysis, we made STEAM publicly available at © 2015 Elsevier Inc.

Karakochuk C.D.,University of British Columbia | Karakochuk C.D.,The Child and Family Research Institute | Whitfield K.C.,University of British Columbia | Whitfield K.C.,The Child and Family Research Institute | And 12 more authors.
Journal of Nutrition | Year: 2015

Background: Anemia is common in Cambodian women. Potential causes include micronutrient deficiencies, genetic hemoglobin disorders, inflammation, and disease. Objectives: We aimed to investigate factors associated with anemia (low hemoglobin concentration) in rural Cambodian women (18-45 y) and to investigate the relations between hemoglobin disorders and other iron biomarkers. Methods: Blood samples were obtained from 450 women. A complete blood count was conducted, and serum and plasma were analyzed for ferritin, soluble transferrin receptor (sTfR), folate, vitamin B-12, retinol binding protein (RBP), C-reactive protein (CRP), and a1 acid glycoprotein (AGP). Hemoglobin electrophoresis and multiplex polymerase chain reaction were used to determine the prevalence and type of genetic hemoglobin disorders. Results: Overall, 54% of women had a genetic hemoglobin disorder, which included 25 different genotypes (most commonly, hemoglobin E variants and α3.7-thalassemia). Of the 420 nonpregnant women, 29.5% had anemia (hemoglobin <120 g/L), 2% had depleted iron stores (ferritin <15 mg/L), 19% had tissue iron deficiency (sTfR >8.3 μg/L), <3% had folate deficiency (<3 μg/L), and 1%had vitamin B-12 deficiency (<150 pmol/L). Prevalences of iron deficiency anemia (IDA) were 14.2% and 1.5% in those with and without hemoglobin disorders, respectively. There was no biochemical evidence of vitamin A deficiency (RBP <0.7 μmol/L). Acute and chronic inflammation were prevalent among 8% (CRP >5 mg/L) and 26% (AGP >1 g/L) of nonpregnant women, respectively. By using an adjusted linear regression model, the strongest predictors of hemoglobin concentration were hemoglobin E homozygous disorder and pregnancy status. Other predictors were 2 other heterozygous traits (hemoglobin E and Constant Spring), parity, RBP, log ferritin, and vitamin B-12. Conclusions: Multiple biomarkers for anemia and iron deficiency were significantly influenced by the presence of hemoglobin disorders, hence reducing their diagnostic sensitivity. Further investigation of the unexpectedly low prevalence of IDA in Cambodian women is warranted. © 2015 American Society for Nutrition.

Karakochuk C.D.,University of British Columbia | Karakochuk C.D.,The Child and Family Research Institute | Whitfield K.C.,University of British Columbia | Whitfield K.C.,The Child and Family Research Institute | And 12 more authors.
Journal of Nutrition | Year: 2015

Background: Ferritin and soluble transferrin receptor (sTfR) concentrations are commonly used to assess iron deficiency (ID); however, they are influenced by multiple factors. Objectives: We assessed associations between numerous variables and both ferritin and sTfR concentrations in Cambodian women and compared ID prevalence through the use of study-generated correction factors (CFs) for ferritin with those from a published meta-analysis. Methods: Venous blood from 450 women (aged 18-45 y) was assessed for hemoglobin (Hb), ferritin, sTfR, retinol binding protein, folate, vitamin B-12, C-reactive protein, α-1 acid glycoprotein (AGP), and genetic Hb disorders. Linear regression was used to calculate geometric mean ratios (95% CIs) for ferritin and sTfR concentrations. Results: The variant Hb EE genotype was associated with 50% (14%, 96%) and 51% (37%, 66%) higher geometric mean ferritin and sTfR concentrations, respectively, than was the normal Hb AA genotype; a 1-g/L increase in AGP was associated with 99% (50%, 162%) and 48% (33%, 64%) higher concentrations in the same variables, respectively. ID prevalence in nonpregnant women (n = 420) was 2% (n = 9) with the use of ferritin <15 μg/L and 18% (n = 79) with the use of sTfR >8.3 μg/L as criteria. ID prevalence with the use of sTfR was higher in women with the Hb EE genotype (n = 17; 55%) than in those with the Hb AA genotype (n = 20; 10%); and in women with the Hb AA genotype and chronic inflammation (n = 10; 18%) than in that group of women without chronic inflammation (n = 10; 7%) (P < 0.05). No differences in ID prevalence were found with the use of ferritin between women with Hb EE and AA genotypes (P=1.0) or by chronic inflammation status (P=0.32). There were no differences in mean ferritin concentrations among all 450 women when study-generated CFs were compared with those from the meta-analysis (P = 0.87). Conclusions: Compared with sTfR, ferritin concentrations appear to reflect more accurately true ID in rural Cambodian women. The CFs from a published meta-analysis were appropriate for use in this population with a high prevalence of Hb disorders and inflammation. © 2015 American Society for Nutrition.

Cotton A.M.,University of British Columbia | Cotton A.M.,NRC Steacie Institute for Molecular Sciences | Price E.M.,University of British Columbia | Price E.M.,The Child and Family Research Institute | And 10 more authors.
Human Molecular Genetics | Year: 2015

X-chromosome inactivation (XCI) achieves dosage compensation between males and females through the silencing of the majority of genes on one of the female X chromosomes. Thus, the female X chromosomes provide a unique opportunity to study euchromatin and heterochromatin of allelic regions within the same nuclear environment. We examined the interplay of DNA methylation (DNAm) with CpG density, transcriptional activity and chromatin state at genes on the X chromosome using over 1800 female samples analysed with the Illumina Infinium Human Methylation450 BeadChip. DNAm was used to predict an inactivation status for 63 novel transcription start sites (TSSs) across 27 tissues. There was high concordance of inactivation status across tissues, with 62% of TSSs subject to XCI in all 27 tissues examined, whereas 9% escaped from XCI in all tissues, and the remainder showed variable escape from XCI between females in subsets of tissues. Inter-female and twin data supported a model of predominately cis-acting influences on inactivation status. The level of expression from the inactive X relative to the active X correlated with the amount of female promoter DNAm to a threshold of ~30%, beyond which genes were consistently subject to inactivation. The inactive X showed lower DNAm than the active X at intragenic and intergenic regions for genes subject to XCI, but not at genes that escape from inactivation. Our categorization of genes that escape from X inactivation provides candidates for sex-specific differences in disease. © The Author 2014. Published by Oxford University Press.

Martin-Herz S.P.,University of Washington | Zatzick D.F.,University of Washington | McMahon R.J.,Simon Fraser University | McMahon R.J.,The Child and Family Research Institute
Clinical Child and Family Psychology Review | Year: 2012

This paper comprehensively reviews the published literature investigating health-related quality of life (HRQOL) following general traumatic injury in individuals between birth and 18 years. Studies were not considered if they primarily compared medical treatment options, evaluated physical function but not other aspects of HRQOL, or focused on non-traumatic wounds. Specific injury types (e. g., burn injury) were also not included. A total of 16 studies met criteria. Participants were age 1-18 years, with 12 studies considering children 5 years of age or older. Males were overrepresented. Injury severity averaged mostly in the moderate range. HRQOL deficits were noted in injured samples in all studies except the two with the longest time to follow-up (6-11 years). Some improvement was seen 6 months to 2 years after injury. Factors associated with HRQOL deficits were investigated, with acute and posttraumatic stress disorder symptoms showing the strongest relationship. Research to date in this area is impressive, particularly the number of studies using prospective longitudinal investigations and validated measures. Challenges remain regarding methodologic differences, assessment of preinjury status, retention of participants, and management of missing data. Suggested future directions include extension of follow-up duration, utilization of pediatric self-report when possible, inclusion of younger children, and development of intervention programs. © 2012 Springer Science+Business Media, LLC.

Christians J.K.,Simon Fraser University | Beristain A.G.,University of British Columbia | Beristain A.G.,The Child and Family Research Institute
Cell Adhesion and Migration | Year: 2016

Proper placental development and function is crucial for a healthy pregnancy, and there has been substantial research to identify markers of placental dysfunction for the early detection of pregnancy complications. Low first-trimester levels of a disintegrin and metalloproteinase 12 (ADAM12) and pregnancy-associated plasma protein-A (PAPP-A) have been consistently associated with the subsequent development of preeclampsia and fetal growth restriction. These molecules are both metalloproteinases secreted by the placenta that cleave insulin-like growth factor binding proteins (IGFBPs), although ADAM12 also has numerous other substrates. Recent work has identified ADAM12, and particularly its shorter variant, ADAM12S, as a regulator of the migration and invasion of trophoblasts into the lining of the uterus, a critical step in normal placental development. While the mechanisms underlying this regulation are not yet clear, they may involve the liberation of heparin-binding EGF-like growth factor (HB-EGF) and/or IGFs from IGFBPs. In contrast, there has been relatively little functional work examining PAPP-A or the IGFBP substrates of ADAM12 and PAPP-A. Understanding the functions of these markers and the mechanisms underlying their association with disease could improve screening strategies and enable the development of new therapeutic interventions. © 2016 Taylor & Francis Group, LLC.

Aghababaei M.,University of British Columbia | Perdu S.,The Child and Family Research Institute | Irvine K.,The Child and Family Research Institute | Beristain A.G.,University of British Columbia | Beristain A.G.,The Child and Family Research Institute
Molecular Human Reproduction | Year: 2014

During pregnancy, stromal- and vascular-remodeling trophoblasts serve critical roles in directing placental development acquiring pro-invasive characteristics. The A Disintegrin and Metalloproteinase (ADAM) family of multifunctional proteins direct cellular processes across multiple organ systems via their intrinsic catalytic, cell adhesive and intracellular signaling properties. ADAM12, existing as two distinct splice variants (ADAM12L and ADAM12S), is highly expressed in the human placenta and promotes cell migration and invasion in several tumor cell lines; however, its role in trophoblast biology is unknown. In this study, ADAM12 was localized to anchoring trophoblast columns in first trimester placentas and to highly invasive extracellular matrix-degrading trophoblasts in placental villous explants. The importance of ADAM12 in directing trophoblast invasion was tested using loss-of and gain-of-function strategies, where siRNA-directed knockdown of ADAM12 inhibited trophoblast cell invasion while over-expression promoted migration and invasion in two trophoblastic cell models. In placental villous explant cultures, siRNA-directed loss of ADAM12 significantly dampened trophoblast column outgrowth. Additionally, we provide functional evidence for the ADAM12S variant in promoting trophoblast invasion and column outgrowth through a mechanism requiring its catalytic activity. This is the first study to assign a function for ADAM12 in trophoblast biology, where ADAM12 may play a central role regulating the behavior of invasive trophoblast subsets in early pregnancy. This study also underlines the importance of ADAM12L and ADAM12S in directing cell motility in normal developmental processes outside of cancer, specifically highlighting a potentially important function of ADAM12S in directing early placental development. © The Author 2013. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved.

Crosley E.J.,Simon Fraser University | Dunk C.E.,Mount Sinai Hospital | Beristain A.G.,University of British Columbia | Beristain A.G.,The Child and Family Research Institute | Christians J.K.,Simon Fraser University
Reproductive Biology and Endocrinology | Year: 2014

Background: Adverse gestational outcomes such as preeclampsia (PE) and intrauterine growth restriction (IUGR) are associated with placental insufficiency. Normal placental development relies on the insulin-like growth factors -I and -II (IGF-I and -II), in part to stimulate trophoblast proliferation and extravillous trophoblast (EVT) migration. The insulin-like growth factor binding proteins (IGFBPs) modulate the bioavailability of IGFs in various ways, including sequestration, potentiation, and/or increase in half-life. The roles of IGFBP-4 and -5 in the placenta are unknown, despite consistent associations between pregnancy complications and the levels of two IGFBP-4 and/or -5 proteases, pregnancy-associated plasma protein -A and -A2 (PAPP-A and PAPP-A2). The primary objective of this study was to elucidate the effects of IGFBP-4 and -5 on IGF-I and IGF-II in a model of EVT migration. A related objective was to determine the timing and location of IGFBP-4 and -5 expression in the placental villi. Methods: We used wound healing assays to examine the effects of IGFBP-4 and -5 on the migration of HTR-8/SVneo cells following 4 hours of serum starvation and 24 hours of treatment. Localization of IGFBP-4, -5 and PAPP-A2 was assessed by immunohistochemical staining of first trimester placental sections. Results: 2 nM IGF-I and -II each increased HTR-8/SVneo cell migration with IGF-I increasing migration significantly more than IGF-II. IGFBP-4 and -5 showed different levels of inhibition against IGF-I. 20 nM IGFBP-4 completely blocked the effects of 2 nM IGF-I, while 20 nM IGFBP-5 significantly reduced the effects of 2 nM IGF-I, but not to control levels. Either 20 nM IGFBP-4 or 20 nM IGFBP-5 completely blocked the effects of 2 nM IGF-II. Immunohistochemistry revealed co-localization of IGFBP-4, IGFBP-5 and PAPP-A2 in the syncytiotrophoblast layer of first trimester placental villi as early as 5 weeks of gestational age. Conclusions: IGFBP-4 and -5 show different levels of inhibition on the migration-stimulating effects of IGF-I and IGF-II, suggesting different roles for PAPP-A and PAPP-A2. Moreover, co-localization of the pappalysins and their substrates within placental villi suggests undescribed roles of these molecules in early placental development. © Crosley et al.; licensee BioMed Central Ltd.

PubMed | the Child and Family Research Institute
Type: Journal Article | Journal: CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne | Year: 2012

There have been several published reports of inflammatory ocular adverse events, mainly uveitis and scleritis, among patients taking oral bisphosphonates. We examined the risk of these adverse events in a pharmacoepidemiologic cohort study.We conducted a retrospective cohort study involving residents of British Columbia who had visited an ophthalmologist from 2000 to 2007. Within the cohort, we identified all people who were first-time users of oral bisphosphonates and who were followed to the first inflammatory ocular adverse event, death, termination of insurance or the end of the study period. We defined an inflammatory ocular adverse event as scleritis or uveitis. We used a Cox proportional hazard model to determine the adjusted rate ratios. As a sensitivity analysis, we performed a propensity-score-adjusted analysis.The cohort comprised 934,147 people, including 10,827 first-time users of bisphosphonates and 923,320 nonusers. The incidence rate among first-time users was 29/10,000 person-years for uveitis and 63/10,000 person-years for scleritis. In contrast, the incidence among people who did not use oral bisphosphonates was 20/10,000 person-years for uveitis and 36/10,000 for scleritis (number needed to harm: 1100 and 370, respectively). First-time users had an elevated risk of uveitis (adjusted relative risk [RR] 1.45, 95% confidence interval [CI] 1.25-1.68) and scleritis (adjusted RR 1.51, 95% CI 1.34-1.68). The rate ratio for the propensity-score-adjusted analysis did not change the results (uveitis: RR 1.50, 95% CI 1.29-1.73; scleritis: RR 1.53, 95% CI 1.39-1.70).People using oral bisphosphonates for the first time may be at a higher risk of scleritis and uveitis compared to people with no bisphosphonate use. Patients taking bisphosphonates must be familiar with the signs and symptoms of these conditions, so that they can immediately seek assessment by an ophthalmologist.

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