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Gregory M.K.,Rheumatology Unit | Lester S.E.,Basil Hetzel Institute for Medical Research | Cook-Johnson R.J.,Rheumatology Unit | Gibson R.A.,University of Adelaide | And 3 more authors.
European Journal of Human Genetics | Year: 2011

Dietary essential polyunsaturated fatty acids (PUFAs) require fatty acid desaturases (FADS) for conversion to long-chain PUFAs (LCPUFAs), which are critical for many aspects of human health. A Δ6-desaturase deficiency in a single patient was attributed to an insertion mutation in the FADS2 promoter. Later population studies have shown this thymidine nucleotide (T) insertion to be a common polymorphism (rs3834458). We examined correlations between rs3834458 variants and fatty acid evidence of FADS2 activity in a cohort of rheumatoid arthritis patients selected for low or nil consumption of n-3 LCPUFA as fish or fish oil. The presence of the T allele was associated with higher FADS2 activity, as indicated by higher conversion of plasma n-3 PUFA to LCPUFA. However, the T-insertion/deletion polymorphism did not affect FADS2 promoter activity in luciferase reporter assays in HepG2 or NIH/3T3 cells. Our results indicate that the polymorphism rs3834458 does not appear to directly affect FADS2 promoter activity and is not responsible for a previously reported Δ6-desaturase deficiency. © 2011 Macmillan Publishers Limited All rights reserved.

Ng J.,University of Adelaide | Ng J.,Basil Hetzel Institute for Medical Research | Kidd S.P.,University of Adelaide
International Journal of Medical Microbiology | Year: 2013

Of the known proteins which use nickel as a co-factor, Haemophilus influenzae contains only urease and glyoxalase I (gloA). We have recently reported that this pathogen harbours a unique nickel uptake system (nikKLMQO-nimR). Unusually, the disruption of the nickel uptake system (nikQ or nimR mutants) resulted in cells that aggregated and formed an increased biofilm compared to the wild type cells. Using a gloA mutant strain and urease-specific inhibitor we showed that this phenotype is not due to the loss-of-function of these enzymes. By generating H. influenzae " resting cells" which are enzymatically inactive but maintain their structural integrity we have shown that the cell aggregation in the nikQ/. nimR mutants is not due to the loss of enzymatic function. The nikQ mutant was unable to accumulate nickel but the addition of excess nickel did restore intracellular nickel levels and this resulted in the nikQ mutant returning to the wild type " free-living" phenotype; cells with no aggregation and no biofilm formation. We used a range of techniques which showed that the nikQ mutant possesses changes to its cell surface properties. The mutant was more negatively charged than wild type cells as well as being more hydrophobic. Analysis of the outer membrane constituents showed that there were molecular differences. Although the nikQ mutant appears to grow the same as its wild type cell we have shown that there is a change in the " lifestyle" of these nickel limited cells and this induces changes to the surface of the cell to promote cell-cell aggregation and biofilm formation. © 2013 Elsevier GmbH.

Cummins A.G.,Basil Hetzel Institute for Medical Research | Alexander B.G.,Queen Elizabeth Hospital | Chung A.,Queen Elizabeth Hospital | Teo E.,Queen Elizabeth Hospital | And 4 more authors.
American Journal of Gastroenterology | Year: 2011

Objectives: The Marsh classification is a semiquantitative method for the diagnosis and monitoring of changes in duodenal biopsies in celiac disease. We have explored the possibility that quantitative changes in villous area and crypt length (morphometry) may provide better information on changes in duodenal morphology, particularly after the introduction of a gluten-free diet. Methods: We measured villous height, apical and basal villous widths, and crypt length in 57 adults with celiac disease and 83 control subjects. Villous area was calculated as a trapezoid approximation. Serial changes in villous area and crypt length were determined at regular intervals for up to 4 years after the introduction of a gluten-free diet. Morphometric changes were also correlated with Marsh grade, self-reported adherence to a gluten-free diet, and changes in celiac serology. Results: The gluten-free diet resulted in a progressive increase in villous area and a progressive decrease in crypt length. Morphometric improvement reached a plateau after 6-12 months with mean villous area attaining a value approximately half that of control subjects. Morphometric data were more sensitive than Marsh grade. Improvement in morphometric indices was significantly associated with the disappearance of anti-endomysial IgA antibody but not with dietary compliance. Conclusions: Morphometry is a sensitive way to document changes in duodenal biopsies in celiac disease. In adults treated with a gluten-free diet, it is uncommon for villous area to return to values observed in control subjects, but morphometric improvement is associated with the disappearance of anti-endomysial IgA antibody. © 2011 by the American College of Gastroenterology.

Collins M.G.,Central Northern Adelaide Renal and Transplantation Service | Collins M.G.,Basil Hetzel Institute for Medical Research | Collins M.G.,University of Adelaide | Rogers N.M.,Central Northern Adelaide Renal and Transplantation Service | And 11 more authors.
Journal of Medical Primatology | Year: 2014

Background: Common marmosets are known to develop an IgM glomerulopathy, which has been linked with 'wasting marmoset' syndrome. This study investigated renal pathology in a colony of marmosets, with and without weight loss. Methods: Renal histology, immunofluorescence, and electron microscopy were performed on marmosets euthanized for research or for weight loss. Serum and urine biochemistry were measured during life and at euthanasia. Results: Histology from 25 adult marmosets (19 research and 6 weight loss) showed mesangial expansion in the majority of glomeruli. Mesangial changes correlated with electron-dense deposits and IgM deposition by immunofluorescence; negligible other pathology was seen. Glomerular basement membrane thickness appeared increased compared to reported human measurements. Low-grade proteinuria was present in all animals, but did not progress. Renal function was normal in all animals. Conclusions: Marmosets develop a glomerulopathy characterized by mesangial expansion, IgM deposition, and proteinuria. This is a benign occurrence and not specifically associated with weight loss. © 2014 John Wiley & Sons A/S.

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