Melbourne Dental School - Research Publications
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ItemMaxillonasal dysplasia (Binder syndrome): a lateral cephalometric assessment.(Walter de Gruyter GmbH, 2002-11)Binder syndrome or maxillonasal dysplasia was first described by Binder in 1962, and is a disorder characterised by nasomaxillary hypoplasia. The records of 33 patients who had been diagnosed clinically with Binder syndrome at the Royal Children's Hospital of Melbourne were examined. Of these 33 patients, 14 were selected because they met the incusion criteria: that they had not had prior surgical and/or orthodontic treatment, and that high-quality lateral cephalometric radiographs were available. The craniofacial morphology of these patients was determined on lateral cephalometric radiographs and compared with published age- and sex-matched norms. In agreement with published studies, the anteroposterior lengths of the anterior cranial base and maxilla were reduced, and the majority of patients had a Class III skeletal relationship. Although the lower incisors tended to be prominent, both overjet and overbite 'ell within the ranges for the normal population. Despite the fact that the orthodontic and surgical treatment for patients with Binder syndrome is normally carried out within specialised units, clinicians should be aware of the variety of ways in which this condition may present.
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ItemNo Preview AvailableRegulation of the endosomal SNARE protein syntaxin 7 by colony-stimulating factor 1 in macrophages(AMER SOC MICROBIOLOGY, 2008-10)Colony-stimulating factor 1 (CSF-1) is the main growth factor controlling the development of macrophages from myeloid progenitor cells. However, CSF-1 also regulates some of the key effector functions of macrophages (e.g., phagocytosis and cytokine secretion). The endosomal SNARE protein syntaxin 7 (Stx7) regulates vesicle trafficking events involved in phagocytosis and cytokine secretion. Therefore, we investigated the ability of CSF-1 to regulate Stx7. CSF-1 upregulated Stx7 expression in primary mouse macrophages; it also upregulated expression of its SNARE partners Vti1b and VAMP8 but not Stx8. Additionally, CSF-1 induced the rapid serine phosphorylation of Stx7 and enhanced its binding to Vti1b, Stx8, and VAMP8. Bioinformatics analysis and results from experiments with kinase inhibitors suggested the CSF-1-induced phosphorylation of Stx7 was mediated by protein kinase C and Akt in response to phosphatidylinositol 3-kinase activation. Based on mutagenesis studies, CSF-1 appeared to increase the binding of Stx7 to its SNARE partners by inducing the phosphorylation of serine residues in the Habc domain and/or "linker" region of Stx7. Thus, CSF-1 is a key regulator of Stx7 expression and function in macrophages. Furthermore, the effects of CSF-1 on Stx7 may provide a mechanism for the regulation of macrophage effector functions by CSF-1.
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ItemBilateral Distraction Osteogenesis of Vascularized Iliac Crest Free Flaps Used in Mandibular Reconstruction.(Ovid Technologies (Wolters Kluwer Health), 2016-03)Vascularized free flaps have become the gold standard in reconstructing large segmental mandibular defects; however, even when bony union and soft-tissue coverage is achieved, insufficient bone stock and altered facial contour can create functional and cosmetic problems for the patient. There have been limited case reports on the use of secondary distraction osteogenesis to address these issues. The authors report a case of bilateral mandibular distraction of deep circumflex iliac artery free flaps, used for mandibular reconstruction after total mandibulectomy for treatment of osteosarcoma. Performed for reasons of retrognathia and facilitation of dental prosthetic rehabilitation, this is the first case of bilateral horizontal distraction osteogenesis of deep circumflex iliac artery free flaps reported in the literature.
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ItemKimura's disease: an uncommon cause of head and neck masses with potentially serious sequelae(OXFORD UNIV PRESS, 2015-10)Kimura's disease (KD) typically presents as a mass in the head and neck region in association with eosinophilia and elevated serum IgE. Excisional biopsy is often required in order to obtain an adequate sample for histological diagnosis and exclude malignancy. If suspected, patients should also be investigated for renal involvement as this may complicate KD. Treatment options include surgical excision and medical therapies such as corticosteroids depending on the extent and severity of disease.
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ItemSupport for the Microgenderome: Associations in a Human Clinical Population.(Springer Science and Business Media LLC, 2016-01-13)The 'microgenderome' provides a paradigm shift that highlights the role of sex differences in the host-microbiota interaction relevant for autoimmune and neuro-immune conditions. Analysis of cross-sectional self-report and faecal microbial data from 274 patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) suggests that commensal gut microorganisms may play both protective and deleterious roles in symptom expression. Results revealed significant sex-specific interactions between Firmicutes (Clostridium, Streptococcus, Lactobacillus and Enterococcus) and ME/CFS symptoms (including neurological, immune and mood symptoms), regardless of compositional similarity in microbial levels across the sexes. Extending animal studies, we provide support for the microgenderome in a human clinical population. Applied and mechanistic research needs to consider sex-interactions when examining the composition and function of human microbiota.
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ItemSleep quality and the treatment of intestinal microbiota imbalance in Chronic Fatigue Syndrome: A pilot study.(Georg Thieme Verlag KG, 2015-11)Chronic Fatigue Syndrome (CFS) is a multisystem illness, which may be associated with imbalances in gut microbiota. This study builds on recent evidence that sleep may be influenced by gut microbiota, by assessing whether changes to microbiota in a clinical population known to have both poor sleep and high rates of colonization with gram-positive faecal Streptococcus, can improve sleep. Twenty-one CFS participants completed a 22- day open label trial. Faecal microbiota analysis was performed at baseline and at the end of the trial. Participants were administered erythromycin 400 mg b.d. for 6 days. Actigraphy and questionnaires were used to monitor sleep, symptoms and mood. Changes in patients who showed a clinically significant change in faecal Streptococcus after treatment (responders; defined as post-therapy distribution<6%) were compared to participants who did not respond to treatment. In the seven responders, there was a significant increase in actigraphic total sleep time (p=0.028) from baseline to follow up, compared with non-responders. Improved vigour scores were associated with a lower Streptococcus count (ρ=-0.90, p=0.037). For both the responders and the whole group, poorer mood was associated with higher Lactobacillus. Short term antibiotic treatment appears to be insufficient to effect sustainable changes in the gut ecosystem in most CFS participants. Some improvement in objective sleep parameters and mood were found in participants with reduced levels of gram-positive gut microbiota after antibiotic treatment, which is encouraging. Further study of possible links between gut microorganisms and sleep and mood disturbances is warranted.
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ItemExamining the relationship between childhood health conditions and health service utilisation at school entry and subsequent academic performance in a large cohort of Australian children(WILEY-BLACKWELL, 2016-07)AIM: Chronic health conditions are associated with poor academic outcomes. This study examines the relationship between health conditions, specialist health service utilisation and academic performance in Australian children. METHODS: This was a quasi-longitudinal study where School Entrant Health Questionnaire (a survey tool with parent report on children's health) data for 24 678 children entering school in 2008 was matched with the 2011 National Assessment Program - Literacy and Numeracy (NAPLAN). Linear and logistic regressions were used to examine associations between health conditions, use of a specialist health service and reading and numeracy scores. RESULTS: The study comprised 24 678 children. Children with allergies, very low birth weight, developmental delay, diabetes, spina bifida, cystic fibrosis, birth abnormality, speech problems, intellectual disability and attention-deficit/hyperactivity disorder had lower numeracy scores than those without any of these conditions (P < 0.05). The same children had higher odds (1.2-5.8) of being at or below the national minimum standard for numeracy. Children with developmental delay, epilepsy, dental problems, speech, intellectual disabilities and low birth weight had lower reading scores than those without these conditions (P < 0.05) and had higher odds of being at (odds ratio: 1.3) or below (odds ratio: 3.7) the national minimum standard for reading. Children with health conditions who had ever accessed specialist health services did not differ in their academic performance from those that had not used specialist health services. CONCLUSIONS: Some health conditions put children at risk of poorer academic performance, and interventions to prevent this such as appropriate support services in schools should be considered.
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ItemAntimicrobial activity and regulation of CXCL9 and CXCL10 in oral keratinocytes(WILEY, 2016-10)Chemokine (C-X-C motif) ligand (CXCL)9 and CXCL10 are dysregulated in oral inflammatory conditions, and it is not known if these chemokines target microorganisms that form oral biofilm. The aim of this study was to investigate the antimicrobial activity of CXCL9 and CXCL10 on oral microflora and their expression profiles in oral keratinocytes following exposure to inflammatory and infectious stimuli. Streptococcus sanguinis was used as a model and Escherichia coli as a positive control. The antimicrobial effect of CXCL9/CXCL10 was tested using a radial diffusion assay. mRNA transcripts were isolated from lipopolysaccharide (LPS)-treated and untreated (control) oral keratinocyte cell lines at 2-, 4-, 6-, and 8-h time-points of culture. The CXCL9/10 expression profile in the presence or absence of interferon-γ (IFN-γ) was assessed using semiquantitative PCR. Although both chemokines demonstrated antimicrobial activity, CXCL9 was the most effective chemokine against both S. sanguinis and E coli. mRNA for CXCL10 was expressed in control cells and its production was enhanced at all time-points following stimulation with LPS. Conversely, CXCL9 mRNA was not expressed in control or LPS-stimulated cells. Finally, stimulation with IFN-γ enhanced basal expression of both CXCL9 and CXCL10 in oral keratinocytes. Chemokines derived from oral epithelium, particularly CXCL9, demonstrate antimicrobial properties. Bacterial and inflammatory-stimulated up-regulation of CXCL9/10 could represent a key element in oral bacterial colonization homeostasis and host-defense mechanisms.
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ItemCandida virulence and ethanol-derived acetaldehyde production in oral cancer and non-cancer subjects(WILEY, 2016-11)OBJECTIVES: To compare biofilm-forming ability, hydrolytic enzymes and ethanol-derived acetaldehyde production of oral Candida isolated from the patients with oral cancer and matched non-oral cancer. MATERIAL AND METHODS: Fungal biofilms were grown in RPMI-1640 medium, and biofilm mass and biofilm activity were assessed using crystal violet staining and XTT salt reduction assays, respectively. Phospholipase, proteinase, and esterase production were measured using agar plate method, while fungal acetaldehyde production was assessed via gas chromatography. RESULTS: Candida isolated from patients with oral cancer demonstrated significantly higher biofilm mass (P = 0.031), biofilm metabolic activity (P < 0.001), phospholipase (P = 0.002), and proteinase (P = 0.0159) activity than isolates from patients with non-oral cancer. High ethanol-derived acetaldehyde-producing Candida were more prevalent in patients with oral cancer than non-oral cancer (P = 0.01). In univariate regression analysis, high biofilm mass (P = 0.03) and biofilm metabolic activity (P < 0.001), high phospholipase (P = 0.003), and acetaldehyde production ability (0.01) were significant risk factors for oral cancer; while in the multivariate regression analysis, high biofilm activity (0.01) and phospholipase (P = 0.01) were significantly positive influencing factors on oral cancer. CONCLUSION: These data suggest a significant positive association between the ability of Candida isolates to form biofilms, to produce hydrolytic enzymes, and to metabolize alcohol to acetaldehyde with their ability to promote oral cancer development.
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ItemThirty-six month clinical evaluation of a highly filled flowable composite for direct posterior restorations(WILEY, 2016-09)BACKGROUND: The aim of this randomized controlled study was to evaluate the clinical performance of a highly filled flowable composite compared to a conventional paste-type composite in direct posterior restorations after 36 months. METHODS: A total of 58 mid-size to extensive posterior composite restorations were randomly placed in 32 patients, mean age of 43.9 years (range 25-76), using either a conventional composite Estelite Sigma Quick (Conventional) or a highly filled flowable composite G-aenial Universal Flo with a two-step self-etch adhesive. The restorations were evaluated after placement (baseline) and at 6, 12, 24 and 36 months according to the FDI criteria. RESULTS: At the 36-month follow-up, 42 restorations were evaluated in 21 patients. After 36 months, the difference between highly filled flowable and conventional restorations was not statistically significant with respect to all evaluation parameters (p < 0.05). No secondary caries was observed. CONCLUSIONS: The highly filled flowable composite showed a comparable clinical effectiveness as the conventional paste composite in posterior restorations over 36 months.