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North Adelaide, Australia

Hosking J.,Womens and Childrens Hospital | Zoanetti D.,Womens and Childrens Hospital | Zoanetti D.,University of Adelaide | Carlyle A.,Princess Margaret Hospital | And 4 more authors.
Paediatric Anaesthesia | Year: 2012

Objectives: To review airway management with anesthesia for children with Treacher Collins syndrome (TCS) and determine whether intubation was more difficult with increasing age. Background: Treacher Collins syndrome is a rare disorder of craniofacial development characterized by maxillary, zygomatic, and mandibular dysplasia. TCS is associated with difficult intubation, but reports of airway management are limited to case reports and small cases series. Children with TCS may require multiple general anesthetics, and it has been suggested that intubation becomes more difficult with increasing age. Methods: A retrospective case note review of children with TCS from birth to 18 years undergoing anesthesia from 1971 to 2011 in a single center was performed. Demographic data, procedure type, anesthesia type, method of airway management, modified Cormack-Lehane (MCL) grade of laryngoscopic view, and any other descriptions of airway difficulty or complications were collated. Results: Of 59 patients with TCS, 35 children underwent a total of 240 anesthetics, most commonly for craniofacial surgery. Final airway management consisted of face mask 17%, laryngeal mask airway 16%, endotracheal intubation 49%, and 18% had a preexisting tracheostomy. The laryngeal mask airway provided an adequate airway in all cases when it was used. MCL grade was recorded in 97 cases involving 28 patients: 7% grade 1, 9% grade 2a, 31% grade 2b, 26% grade 3, and 27% grade 4. Fifteen (54%) patients were MCL grade 4 on at least one occasion. Failed intubation occurred in 6 (5%) of 123 cases of planned intubation. The procedure was canceled in two cases (0.8%) because of failure to intubate. Intubation techniques other than conventional direct laryngoscopy were used in 41% of cases. MCL grade increased with increasing age (P = 0.007). Conclusions: Most children with TCS have difficult laryngoscopic views with many requiring specialized intubation techniques. Direct laryngoscopy becomes more difficult with increasing age. The laryngeal mask airway is a good choice of airway when endotracheal intubation is not required. © 2012 Blackwell Publishing Ltd. Source

Breik O.,Royal Melbourne Hospital | Breik O.,University of Adelaide | Tivey D.,University of Adelaide | Umapathysivam K.,University of Adelaide | And 2 more authors.
International Journal of Oral and Maxillofacial Surgery | Year: 2016

Mandibular distraction osteogenesis (MDO) is increasingly used for neonates and infants with upper airway obstruction secondary to micrognathia. This systematic review was conducted to determine the effectiveness of MDO in the treatment of airway obstruction. The databases searched included PubMed, Embase, Scopus, and grey literature sources. The inclusion criteria were applied to identify studies in children with clinical evidence of micrognathia/Pierre Robin sequence (PRS) who had failed conservative treatments, including both syndromic and non-syndromic patients. Overall 66 studies were included in this review. Primary MDO for the relief of upper airway obstruction was found to be successful at preventing tracheostomy in 95% of cases. Syndromic patients were found to have a four times greater odds of failure compared to those with isolated PRS. The most common causes of failure were previously undiagnosed lower airway obstruction, central apnoea, undiagnosed neurological abnormalities, and the presence of additional cardiovascular co-morbidities. MDO was less effective (81% success rate) at facilitating decannulation of tracheostomy-dependent children (P < 0.0001). Failure in these patients was most commonly due to severe preoperative gastro-oesophageal reflux disease, swallowing dysfunction, and tracheostomy-related complications. The failure rate was higher when MDO was performed at an age of ≥24 months. More studies are needed to evaluate the long-term implications of MDO on facial development and long-term complications. © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Source

Wiszniak S.,University of South Australia | Mackenzie F.E.,University College London | Anderson P.,Australian Craniofacial Unit | Anderson P.,University of Adelaide | And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Jaw morphogenesis depends on the growth of Meckel's cartilage during embryogenesis. However, the cell types and signals that promote chondrocyte proliferation for Meckel's cartilage growth are poorly defined. Here we show that neural crest cells (NCCs) and their derivatives provide an essential source of the vascular endothelial growth factor (VEGF) to enhance jaw vascularization and stabilize the major mandibular artery. We further show in two independent mouse models that blood vessels promote Meckel's cartilage extension. Coculture experiments of arterial tissue with NCCs or chondrocytes demonstrated that NCC-derived VEGF promotes blood vessel growth and that blood vessels secrete factors to instruct chondrocyte proliferation. Computed tomography and X-ray scans of patients with hemifacial microsomia also showed that jaw hypoplasia correlates with mandibular artery dysgenesis. We conclude that cranial NCCs and their derivatives provide an essential source of VEGF to support blood vessel growth in the developing jaw, which in turn is essential for normal chondrocyte proliferation, and therefore jaw extension. © 2015, National Academy of Sciences. All rights reserved. Source

Dwivedi P.P.,Womens and Childrens Health Research Institute | Dwivedi P.P.,University of Adelaide | Anderson P.J.,Womens and Childrens Health Research Institute | Anderson P.J.,University of Adelaide | And 3 more authors.
BMC Biotechnology | Year: 2012

Background: Achieving efficient introduction of plasmid DNA into primary cultures of mammalian cells is a common problem in biomedical research. Human primary cranial suture cells are derived from the connective mesenchymal tissue between the bone forming regions at the edges of the calvarial plates of the skull. Typically they are referred to as suture mesenchymal cells and are a heterogeneous population responsible for driving the rapid skull growth that occurs in utero and postnatally. To better understand the molecular mechanisms involved in skull growth, and in abnormal growth conditions, such as craniosynostosis, caused by premature bony fusion, it is essential to be able to easily introduce genes into primary bone forming cells to study their function.Results: A comparison of several lipid-based techniques with two electroporation-based techniques demonstrated that the electroporation method known as nucleofection produced the best transfection efficiency. The parameters of nucleofection, including cell number, amount of DNA and nucleofection program, were optimized for transfection efficiency and cell survival. Two different genes and two promoter reporter vectors were used to validate the nucleofection method and the responses of human primary suture mesenchymal cells by fluorescence microscopy, RT-PCR and the dual luciferase assay. Quantification of bone morphogenetic protein (BMP) signalling using luciferase reporters demonstrated robust responses of the cells to both osteogenic BMP2 and to the anti-osteogenic BMP3.Conclusions: A nucleofection protocol has been developed that provides a simple and efficient, non-viral alternative method for in vitro studies of gene and protein function in human skull growth. Human primary suture mesenchymal cells exhibit robust responses to BMP2 and BMP3, and thus nucleofection can be a valuable method for studying the potential competing action of these two bone growth factors in a model system of cranial bone growth. © 2012 Dwivedi et al.; licensee BioMed Central Ltd. Source

Cakouros D.,University of Adelaide | Isenmann S.,University of Adelaide | Cooper L.,University of Adelaide | Zannettino A.,University of Adelaide | And 3 more authors.
Molecular and Cellular Biology | Year: 2012

The main impairment to tissue maintenance during aging is the reduced capacity for stem cell self-renewal over time due to senescence, the irreversible block in proliferation. We have previously described that the basic helix-loop-helix (bHLH) transcription factor Twist-1 can greatly enhance the life span of bone marrow-derived mesenchymal stem/stromal cells (MSCs). In the present study, we show that Twist-1 potently suppresses senescence and the Ink4A/Arf locus with a dramatic decrease in the expression of p16 and to some extent a decrease in p14. Furthermore, the polycomb group protein and histone methyltransferase Ezh2, which suppresses the Ink4A/Arf locus, was found to be induced by Twist-1, resulting in an increase in H3K27me3 along the Ink4A/Arf locus, repressing transcription of both p16/p14 and senescence of human MSCs. Furthermore, Twist-1 inhibits the expression of the bHLH transcription factor E47, which is normally expressed in senescent MSCs and induces transcription of the p16 promoter. Reduced Twist-1 wild-type expression and function in bone cells derived from Saethre-Chotzen patients also revealed an increase in senescence. These studies for the first time link Twist-1 to histone methylation of the Ink4A/Arf locus by controlling the expression of histone methyltransferases as well as the expression of other bHLH factors. © 2012, American Society for Microbiology. Source

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