Paediatrics (RCH) - Research Publications

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    Stability of combined Le Fort I maxillary advancement and mandibular reduction.
    Arpornmaeklong, P ; Shand, JM ; Heggie, AA (Walter de Gruyter GmbH, 2003-11)
    BACKGROUND: There have been reports that correction of severe Class III abnormality by single jaw surgery may invite relapse in the long-term. The purpose of this study was to retrospectively evaluate the stability of combined Le Fort I maxillary advancement and bilateral sagittal split osteotomies for mandibular reduction. METHODS: Thirty patients with a skeletal Class III malocclusion underwent bimaxillary surgery using rigid fixation and interpositional bone grafting of the maxilla. The average age was 24.4 years, and the mean follow-up period was 20 months (Range: 12-63 months). Post-operative changes were measured on lateral cephalometric radiographs using an anatomical best-fit technique. RESULTS: The maxilla was advanced, on average, 6.1 mm (SD: 1.8 mm) and repositioned superiorly at PNS 1.9 mm (SD: 2.1 mm). The mandible was repositioned posteriorly 5.6 mm ISD: 4.2 mm) at menton, which also auto-rotated superiorly. At follow-up, the maxilla relapsed horizontally 0.6 mm (SD: 1.1 mm, p < 0.01) with no significant vertical change. The maxillary central incisors were proclined and the interincisal angle was reduced. Menton relapsed anteriorly 1.4 mm (SD: 2.7 mm, p < 0.01), and gonion rotated superiorly 1.5 mm (SD: 2.3 mm, p < 0.001). In 67 per cent of cases menton moved anteriorly less than 2.5 mm. The overjet and overbite did not change significantly. CONCLUSIONS: The data show that 12-months post-operatively, maxillary advancement combined with mandibular setback was relatively stable in the horizontal and vertical planes.
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    Normal skeletal development of mice lacking matrilin 1:: Redundant function of matrilins in cartilage?
    Aszódi, A ; Bateman, JF ; Hirsch, E ; Baranyi, M ; Hunziker, EB ; Hauser, N ; Bösze, Z ; Fässler, R (AMER SOC MICROBIOLOGY, 1999-11)
    Matrilin 1, or cartilage matrix protein, is a member of a novel family of extracellular matrix proteins. To date, four members of the family have been identified, but their biological role is unknown. Matrilin 1 and matrilin 3 are expressed in cartilage, while matrilin 2 and matrilin 4 are present in many tissues. Here we describe the generation and analysis of mice carrying a null mutation in the Crtm gene encoding matrilin 1. Anatomical and histological studies demonstrated normal development of homozygous mutant mice. Northern blot and biochemical analyses show no compensatory up-regulation of matrilin 2 or 3 in the cartilage of knockout mice. Although matrilin 1 interacts with the collagen II and aggrecan networks of cartilage, suggesting that it may play a role in cartilage tissue organization, studies of collagen extractability indicated that collagen fibril maturation and covalent cross-linking were unaffected by the absence of matrilin 1. Ultrastructural analysis did not reveal any abnormalities of matrix organization. These data suggest that matrilin 1 is not critically required for cartilage structure and function and that matrilin 1 and matrilin 3 may have functionally redundant roles.
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    Analysis of the assembly profiles for mitochondrial- and nuclear-DNA-encoded subunits into complex I
    Lazarou, M ; McKenzie, M ; Ohtake, A ; Thorburn, DR ; Ryan, MT (AMER SOC MICROBIOLOGY, 2007-06)
    Complex I of the respiratory chain is composed of at least 45 subunits that assemble together at the mitochondrial inner membrane. Defects in human complex I result in energy generation disorders and are also implicated in Parkinson's disease and altered apoptotic signaling. The assembly of this complex is poorly understood and is complicated by its large size and its regulation by two genomes, with seven subunits encoded by mitochondrial DNA (mtDNA) and the remainder encoded by nuclear genes. Here we analyzed the assembly of a number of mtDNA- and nuclear-gene-encoded subunits into complex I. We found that mtDNA-encoded subunits first assemble into intermediate complexes and require significant chase times for their integration into the holoenzyme. In contrast, a set of newly imported nuclear-gene-encoded subunits integrate with preexisting complex I subunits to form intermediates and/or the fully assembly holoenzyme. One of the intermediate complexes represents a subassembly associated with the chaperone B17.2L. By using isolated patient mitochondria, we show that this subassembly is a productive intermediate in complex I assembly since import of the missing subunit restores complex I assembly. Our studies point to a mechanism of complex I biogenesis involving two complementary processes, (i) synthesis of mtDNA-encoded subunits to seed de novo assembly and (ii) exchange of preexisting subunits with newly imported ones to maintain complex I homeostasis. Subunit exchange may also act as an efficient mechanism to prevent the accumulation of oxidatively damaged subunits that would otherwise be detrimental to mitochondrial oxidative phosphorylation and have the potential to cause disease.
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    No long-term evidence of hyporesponsiveness after use of pneumococcal conjugate vaccine in children previously immunized with pneumococcal polysaccharide vaccine
    Licciardi, PV ; Toh, ZQ ; Clutterbuck, EA ; Balloch, A ; Marimla, RA ; Tikkanen, L ; Lamb, KE ; Bright, KJ ; Rabuatoka, U ; Tikoduadua, L ; Boelsen, LK ; Dunne, EM ; Satzke, C ; Cheung, YB ; Pollard, AJ ; Russell, FM ; Mulholland, EK (Elsevier, 2016-06)
    Background: A randomized controlled trial in Fiji examined the immunogenicity and effect on nasopharyngeal carriage after 0, 1, 2, or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7; Prevnar) in infancy followed by 23-valent pneumococcal polysaccharide vaccine (23vPPV; Pneumovax) at 12 months of age. At 18 months of age, children given 23vPPV exhibited immune hyporesponsiveness to a micro-23vPPV (20%) challenge dose in terms of serotype-specific IgG and opsonophagocytosis, while 23vPPV had no effect on vaccine-type carriage. Objective: This follow-up study examined the long-term effect of the 12-month 23vPPV dose by evaluating the immune response to 13-valent pneumococcal conjugate vaccine (PCV13) administration 4 to 5 years later. Methods: Blood samples from 194 children (now 5-7 years old) were taken before and 28 days after PCV13 booster immunization. Nasopharyngeal swabs were taken before PCV13 immunization. We measured levels of serotype-specific IgG to all 13 vaccine serotypes, opsonophagocytosis for 8 vaccine serotypes, and memory B-cell responses for 18 serotypes before and after PCV13 immunization. Results: Paired samples were obtained from 185 children. There were no significant differences in the serotype-specific IgG, opsonophagocytosis, or memory B-cell response at either time point between children who did or did not receive 23vPPV at 12 months of age. Nasopharyngeal carriage of PCV7 and 23vPPV serotypes was similar among the groups. Priming with 1, 2, or 3 PCV7 doses during infancy did not affect serotype-specific immunity or carriage. Conclusion: Immune hyporesponsiveness induced by 23vPPV in toddlers does not appear to be sustained among preschool children in this context and does not affect the pneumococcal carriage rate in this age group.
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    ANTIGENIC VARIATION IN PLASMODIUM-FALCIPARUM
    BIGGS, BA ; GOOZE, L ; WYCHERLEY, K ; WOLLISH, W ; SOUTHWELL, B ; LEECH, JH ; BROWN, GV (NATL ACAD SCIENCES, 1991-10)
    Antigenic variation of infectious organisms is a major factor in evasion of the host immune response. However, there has been no definitive demonstration of this phenomenon in the malaria parasite Plasmodium falciparum. In this study, cloned parasites were examined serologically and biochemically for the expression of erythrocyte surface antigens. A cloned line of P. falciparum gave rise to progeny that expressed antigenically distinct forms of an erythrocyte surface antigen but were otherwise identical. This demonstrates that antigenic differences on the surface of P. falciparum-infected erythrocytes can arise by antigenic variation of clonal parasite populations. The antigenic differences were shown to result from antigenic variation of the parasite-encoded protein, the P. falciparum erythrocyte membrane protein 1.
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    The Australasian Society for Infectious Diseases guidelines for the diagnosis, management and prevention of infections in recently arrived refugees: an abridged outline
    Murray, RJ ; Davis, JS ; Burgner, DP (WILEY, 2009-04-20)
    About 13,000 refugees are currently accepted for migration into Australia each year, many of whom have spent protracted periods living in extremely disadvantaged circumstances. As a result, medical practitioners are increasingly managing recently arrived refugees with acute and chronic infectious diseases. The Australasian Society for Infectious Diseases has formulated guidelines for the diagnosis, management and prevention of infection in newly arrived refugees. This article is an abridged version of the guidelines, which are available in full at . All refugees should be offered a comprehensive health assessment, ideally within 1 month of arrival in Australia, that includes screening for and treatment of tuberculosis, malaria, blood-borne viral infections, schistosomiasis, helminth infection, sexually transmitted infections, and other infections (eg, Helicobacter pylori) as indicated by clinical assessment; and assessment of immunisation status, and catch-up immunisations where appropriate. The assessment can be undertaken by a general practitioner or within a multidisciplinary refugee health clinic, with use of an appropriate interpreter when required. The initial assessment should take place over at least two visits: the first for initial assessment and investigation and the second for review of results and treatment or referral.
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    The Effect of Intermittent Antenatal Iron Supplementation on Infant Outcomes in Rural Vietnam: A Cluster Randomized Trial
    Hanieh, S ; Ha, T ; Simpson, J ; Casey, G ; Khuong, N ; Thoang, D ; Thuy, T ; Pasricha, S-R ; Tran, T ; Tuan, T ; Dwyer, T ; Fisher, J ; Biggs, B-A (SCIENCEDOMAIN International, 2015)
    Objectives: Intermittent antenatal iron supplementation is an attractive alternative to daily dosing during pregnancy, however the impact of this strategy on infant outcomes remains unclear. We compared the effect of intermittent antenatal iron supplementation with daily iron supplementation on maternal and infant outcomes in rural Vietnam. Methods: This cluster randomised trial was conducted in Ha Nam province, Vietnam. 1,258 pregnant women in 104 communes were assigned to daily iron-folic acid (IFA), twice weekly IFA, or twice weekly multiple micronutrient (MMN) supplementation. Primary outcome was birth weight. Results: There was no difference in birth weights of infants of women receiving twice weekly IFA compared to daily IFA (mean difference [MD] 28 g; 95% CI -22 to 78), or twice weekly MMN compared to daily IFA (MD -36.8 g; 95% CI -82 to 8.2). At 32 wk gestation, maternal ferritin was lower in women receiving twice weekly compared to daily IFA (geometric mean ratio (GMR) 0.73; 95% CI 0.67 to 0.80), and in women receiving twice weekly MMN compared to daily IFA (GMR 0.62; 95% CI 0.57 to 0.68), with no difference in hemoglobin levels. Infants of mothers who received twice weekly IFA had higher cognitive scores at 6 mo of age compared to those who received daily IFA (MD 1.89; 95% CI 0.23 to 3.56). Conclusions: Twice-weekly antenatal IFA supplementation achieved similar mean birthweight, and improved cognitive scores in infants at 6 months of age, compared to daily IFA supplementation, and should be considered for use in settings with low anemia prevalence.
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    Excessive alcohol use and its association with risky sexual behaviour: a cross-sectional analysis of data from Victorian secondary school students
    Agius, P ; Taft, A ; Hemphill, S ; Toumbourou, J ; McMorris, B (WILEY, 2013-02)
    OBJECTIVE: Estimate the prevalence of sexual behaviour and alcohol use and examine the association between excessive alcohol use and risky sexual behaviour in late secondary students in Victoria, Australia. METHOD: The sample of Year 11 students from government and independent schools participating in the 2008 International Youth Development Study (n=450) was representative of the Victorian school population. Logistic regression analyses examined the associations between sexual behaviour, binge and compulsive drinking, adjusting for socio-demographic, school and family factors. RESULTS: Under half (44%) the students had experienced sex in the past year, half (50%) had engaged in binge drinking in the past two weeks and 26% reported compulsive drinking in the past year. Of those who reported sex in the past year (n=197), 34% had sex without a condom at the last sexual encounter and 28% later regretted sex due to alcohol. The likelihood of experiencing sex was increased by binge (OR=2.44, 95%CI 1.44-4.12) and compulsive drinking (OR=2.15, 95%CI 1.29-3.60). For those sexually active, binge drinking increased the risk of having three or more sexual partners (OR=3.37, 95%CI 1.11-10.26) and compulsive drinking increased the likelihood of regretted sex due to alcohol (OR=4.43, 95%CI 2.10-9.31). Excessive drinking was not associated with condom non-use. CONCLUSION AND IMPLICATIONS: Risky sex - multiple sexual partners and regretted sex due to alcohol - and excessive drinking are highly prevalent and co-associated among Victorian late secondary students.
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    The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry
    Roston, TM ; Yuchi, Z ; Kannankeril, PJ ; Hathaway, J ; Vinocur, JM ; Etheridge, SP ; Potts, JE ; Maginot, KR ; Salerno, JC ; Cohen, MI ; Hamilton, RM ; Pflaumer, A ; Mohammed, S ; Kimlicka, L ; Kanter, RJ ; LaPage, MJ ; Collins, KK ; Gebauer, RA ; Temple, JD ; Batra, AS ; Erickson, C ; Miszczak-Knecht, M ; Kubus, P ; Bar-Cohen, Y ; Kantoch, M ; Thomas, VC ; Hessling, G ; Anderson, C ; Young, M-L ; Choi, SHJ ; Ortega, MC ; Lau, YR ; Johnsrude, CL ; Fournier, A ; Van Petegem, F ; Sanatani, S (OXFORD UNIV PRESS, 2018-03)
    AIMS: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes. METHODS AND RESULTS: This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities. CONCLUSION: This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.
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    Atrioventricular block after ASD closure
    Asakai, H ; Weskamp, S ; Eastaugh, L ; d'Udekem, Y ; Pflaumer, A (BMJ PUBLISHING GROUP, 2016)
    OBJECTIVE: Secundum atrial septal defect (ASD) is a common congenital heart defect. There is limited data on both early and late atrioventricular (AV) block post ASD closure. The aim of this study was to determine the incidence and risk factors of AV block associated with ASD closure. METHODS: A retrospective analysis of all patients who underwent ASD closure either with a device or surgical method at the Royal Children's Hospital Melbourne between 1996 and 2010 was performed. Baseline demographics, procedural details and follow-up data were collected from medical records. RESULTS: A total of 378 patients were identified; 242 in the device group and 136 in the surgical group. Fourteen patients (3.7%) had AV block (1 with second degree and 13 with first degree) at a median follow-up of 28 months; 11/242 (4.5%) in the device group and 3/135 (2.2%) in the surgical group (p=0.39). Six patients had new-onset AV block after ASD closure. In the device subgroup, patients with AV block at follow-up had a larger indexed device size compared with those without (22 (15-31) vs 18(7-38), p=0.02). Multivariate analysis revealed the presence of AV block either pre procedure or post procedure to be the only variables associated with late AV block. CONCLUSIONS: Late AV block in patients with repaired ASD is rare and most likely independent of the technique used. In the device subgroup, the only risk factor identified to be associated with late AV block was the presence of either preprocedural or postprocedural AV block, so long-term follow-up for these patients should be provided.