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Dive into the research topics where M. J. Ahern is active.

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Featured researches published by M. J. Ahern.


Annals of the Rheumatic Diseases | 2002

Receptor activator NF-kappaB ligand (RANKL) expression in synovial tissue from patients with rheumatoid arthritis, spondyloarthropathy, osteoarthritis, and from normal patients: semiquantitative and quantitative analysis

Tania N. Crotti; Malcolm D. Smith; Helen Weedon; M. J. Ahern; D M Findlay; Maarten C. Kraan; P P Tak

Objectives: To compare receptor activator of NF-κB ligand (RANKL) production in the synovial tissue from patients with active rheumatoid arthritis (RA), inactive RA, spondyloarthropathies (SpA), osteoarthritis, and from normal subjects. In addition, to establish the cell lineages expressing RANKL in these tissues. Methods: Immunohistological analysis of frozen synovial tissue biopsy specimens was performed using a monoclonal antibody (mAb) to detect RANKL. Sections were evaluated by computer assisted image analysis and semiquantitative analysis to compare RANKL expression between groups. Dual and sequential labelling with mAb RANKL and cell lineage specific monoclonal antibodies were used to determine the types of cells expressing RANKL. Results: Higher levels of RANKL were expressed in tissues from patients with active RA and SpA than in tissues from patients with inactive RA, osteoarthritis, and from normal subjects. RANKL protein was associated with CD3 antigen-positive lymphocytes and some macrophages. RANKL was predominantly associated with activated, memory T cells (CD45Ro positive cells) in patients with active RA and spondyloarthropathy (SpA). Conclusions: The highest levels of RANKL were detected in patients with RA with active synovitis and in some patients with SpA. An increase in RANKL in the inflamed joint of patients with RA, produced by infiltrating activated T cells and macrophages, is likely to be an important cause of joint erosions in RA.


Biomaterials | 2004

Factors regulating osteoclast formation in human tissues adjacent to peri-implant bone loss: expression of receptor activator NFκB, RANK ligand and osteoprotegerin

Tania N. Crotti; Malcolm D. Smith; David M. Findlay; Hala Zreiqat; M. J. Ahern; Helen Weedon; G Hatzinikolous; M. Capone; Christopher A. Holding

Aseptic bone loss adjacent to orthopedic joint implants is a common cause of joint implant failure in humans. This study investigates the expression of key regulators of osteoclast formation, receptor activator NFkappaB (RANK), Receptor activator of NFkappaB ligand (RANKL) and osteoprotegerin (OPG), in the peri-implant tissues of patients with osteolysis compared with levels in synovial tissues from osteoarthritic and healthy subjects. Immunohistochemical studies demonstrated that significantly higher levels of RANKL protein (p<0.05) were found in the peri-implant tissues of patients with implant failure than in similar tissues from osteoarthritic and healthy subjects. In contrast, OPG protein levels were similar in all tissues. RANKL, expressed as mRNA and protein, was predominantly associated with cells containing wear particles. Dual labeling studies showed that the cells expressing RANKL protein were macrophages. In situ hybridization studies confirmed that mRNA encoding for these proteins is also expressed by cells in the peri-implant tissues. In addition, RANK mRNA was expressed in cells that contained wear particles. These findings show that abnormally high levels of RANKL are expressed in peri-implant tissues of patients with prosthetic loosening and that these abnormal levels of RANKL may significantly contribute to aseptic implant loosening.


Annals of the Rheumatic Diseases | 2003

Suprascapular nerve block (using bupivacaine and methylprednisolone acetate) in chronic shoulder pain

Ernst Michael Shanahan; M. J. Ahern; Malcolm D. Smith; M Wetherall; Barry Bresnihan; Oliver FitzGerald

Background: Shoulder pain from inflammatory arthritis and/or degenerative disease is a common cause of morbidity in the community. It is difficult to treat and there are limited data on the efficacy of most interventions. Suprascapular nerve block has shown promise in limited trials in reducing shoulder pain. There have been no large randomised placebo controlled trials examining the efficacy of suprascapular nerve block for shoulder pain in arthritis and/or degenerative disease using pain and disability end points. Objective: To perform a randomised, double blind, placebo controlled trial of the efficacy of suprascapular nerve block for shoulder pain in rheumatoid arthritis (RA) and/or degenerative disease of the shoulder. Methods: 83 people with chronic shoulder pain from degenerative disease or RA took part in the trial. If a person had two painful shoulders, these were randomised separately. A total of 108 shoulders were randomised. Patients in the group receiving active treatment had a single suprascapular nerve block following the protocol described by Dangoisse et al, while those in the other group received a placebo injection of normal saline administered subcutaneously. The patients were followed up for 12 weeks by an observer who was unaware of the randomisation and reviewed at weeks 1, 4, and 12 after the injection. Pain, disability, and range of movement data were gathered. Results: Clinically and statistically significant improvements in all pain scores, all disability scores, and some range of movement scores in the shoulders receiving suprascapular nerve block compared with those receiving placebo were seen at weeks 1, 4, and 12. There were no significant adverse effects in either group. Conclusion: Suprascapular nerve block is a safe and efficacious treatment for the treatment of shoulder pain in degenerative disease and/or arthritis. It improves pain, disability, and range of movement at the shoulder compared with placebo. It is a useful adjunct treatment for the practising clinician to assist in the management of a difficult and common clinical problem.


Internal Medicine Journal | 2001

Scleroderma in South Australia: epidemiological observations of possible pathogenic significance

P. J. Roberts-Thomson; M. Jones; Paul Hakendorf; A. A. S. S. Kencana Dharmapatni; Jenny Walker; J. G. Macfarlane; Malcolm D. Smith; M. J. Ahern

Background: Scleroderma is an autoimmune disorder of unknown cause. Previous epidemiological studies have suggested some regional clustering and associations with occupations involving exposure to silica dusts and hydrocarbons.


Annals of the Rheumatic Diseases | 2003

Microarchitecture and protective mechanisms in synovial tissue from clinically and arthroscopically normal knee joints

Malcolm D. Smith; E C Barg; Helen Weedon; V. Papengelis; Tjm Smeets; P P Tak; Maarten C. Kraan; Mark Coleman; M. J. Ahern

Background: Synovial biopsies are used to study synovial immunopathology and are increasingly applied for the evaluation of new therapeutic strategies in chronic arthritis. Therefore, it is essential to be informed on the complete spectrum of synovial immunopathology. Objective: To describe the cellular content, cytokine and cell adhesion molecule expression in synovial tissue from clinically and arthroscopically normal knees. Methods: Synovial tissue was obtained from 20 normal subjects at the time of knee joint arthroscopy for unexplained knee pain. Tissue sections were studied for basic histopathology and for a range of cell surface markers, cytokines, and cell adhesion molecules by immunoperoxidase staining. Stained sections were evaluated by semiquantitative scoring and digital image analysis. Results: Normal synovial tissue is composed predominantly of fibrofatty areolar tissue, with a variable thickness of intimal lining, composed of both CD68 positive macrophages and CD55 positive fibroblast-like synoviocytes. Interleukin 1 receptor antagonist (IL1Ra) was frequently detected in the synovial membrane of normal subjects (mean (SD) integrated optical density (IOD)=3809.6 (3893.9)), but both tumour necrosis factor α (TNFα) and interleukin 1β (IL1β) were rarely detected. In addition, cell adhesion molecules were rarely detected in the normal synovial membrane, with the exception of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Osteoprotegerin (OPG) expression was abundant on synovial lining macrophages (mean (SD) IOD=5276 (4716) as well as endothelial cells (mean (SD) IOD=557 (226)), but receptor activator of nuclear factor κ ligand (RANKL) expression was rarely seen. Conclusions: The normal synovial membrane has a variable architecture, including thickness of the lining and the subintimal cell infiltrate, with little inflammatory cytokine production or expression of cell adhesion molecules. The excess of OPG expression over RANKL and IL1Ra over IL1 may be important for protection against joint damage


Immunology and Cell Biology | 1993

A comprehensive analysis of peripheral blood lymphocytes in healthy aged humans by flow cytometry

Xiaoning Xu; Ian Beckman; M. J. Ahern; John Bradley

This study used a panel of mAb and multiparameter flow cytometry to assess the composition of PBL from healthy aged individuals. The results showed that while total lymphocyte numbers altered only marginally in the aged (≥ 70 years) there were significant changes in the distribution of various sub‐populations; for example, there were lower numbers of CD3+ and CD8+ cells, and higher numbers of CD16+ (NK) cells. As a direct result of these changes the numbers of CD2+ cells remained unchanged in the aged compared with young adult controls (18–25 years). The number of CD4+ T cells expressing CD45RO isoform (memory cells) exceeded the number of CD4+ CD45RA+ (naive) cells in aged donors, whereas the converse was true for young donors. In addition, associated with this increase in CD45RO+ cells, the aged showed an expanded population of CD45RO+ T cells displaying low surface levels of CD45RO. These data suggest that shifts in the distribution of regulatory T cell subsets may play a role in age‐related changes in immune response.


Internal Medicine Journal | 2005

Isolated pulmonary hypertension in scleroderma

Sally Cox; Jennifer G. Walker; Mark Coleman; Maureen Rischmueller; Susanna Proudman; Malcolm D. Smith; M. J. Ahern; P. J. Roberts-Thomson

Background: Isolated pulmonary hypertension (PHT) is now the most frequent cause of disease‐related death in limited cutaneous scleroderma, the commonest disease variant of this disabling connective tissue disorder. Endothelin‐1 receptor antagonists provide symptomatic benefit but to date have not been shown to prolong survival.


Annals of the Rheumatic Diseases | 2001

Measurement of cytokine and adhesion molecule expression in synovial tissue by digital image analysis.

Maarten C. Kraan; Malcolm D. Smith; Helen Weedon; M. J. Ahern; Ferdinand C. Breedveld; P P Tak

OBJECTIVE Digital image analysis (DIA) offers the opportunity to quantify the stained area and staining intensity when synovial tissue (ST) is investigated by immunohistochemical analysis. This study aimed at determining the sensitivity of DIA compared with semiquantitative analysis (SQA). METHODS Paired ST samples were obtained from the knee joint of 10 patients with rheumatoid arthritis (RA) with active disease and after follow up when complete clinical remission was achieved. ST samples of 10 subjects with non-inflammatory knee pain served as controls. Immunohistochemistry with antibodies against interleukin 1β (IL1β) and vascular cell adhesion molecule 1 (VCAM-1) was applied using two staining protocols with 3-amino-9-ethylcarbazole (AEC) orp-diethylaminobenzaldehyde (DAB) as dye. All sections were analysed semiquantitatively (0–4) and DIA of up to a maximum of 60 high power fields (HPF). The average integrated optical density was calculated as the product of the stained area (corrected for total tissue area) and the optical density. RESULTS Both SQA and DIA enabled the assessment of differences in IL1β and VCAM-1 expression between ST from active RA, RA in remission, and controls. SQA and DIA showed excellent correlations (IL1βr s=0.867; p<0.0001: VCAM-1r s=0.828; p<0.0001). A limited analysis of one region with six HPF still allowed adequate discrimination compared with an extended analysis of three regions with a total of 60 HPF. In general, the red dye (AEC) resulted in better discrimination than the brown (DAB) staining. CONCLUSION DIA offers a reliable, reproducible, and sensitive analysis of ST sections stained for cytokines and adhesion molecules.


Internal Medicine Journal | 2003

Scleroderma renal crisis: poor outcome despite aggressive antihypertensive treatment

Jennifer G. Walker; M. J. Ahern; Malcolm D. Smith; Mark Coleman; K. Pile; Maureen Rischmueller; Leslie G. Cleland; P. J. Roberts-Thomson

Background:  Scleroderma renal crisis (SRC) is a rare but feared complication of scleroderma. Angiotensin‐converting enzyme (ACE) inhibition has significantly improved survival, but it is unknown whether prophylactic ACE inhibitors will prevent this complication.


International Journal of Rheumatic Diseases | 2012

South Australian Scleroderma Register: autoantibodies as predictive biomarkers of phenotype and outcome

Scott W. Graf; Paul Hakendorf; Susan Lester; Karen Patterson; Jenny Walker; Malcolm D. Smith; M. J. Ahern; P. J. Roberts-Thomson

Aim:  To investigate the relationship between scleroderma‐specific autoantibodies and clinical phenotype and survival in South Australian patients with scleroderma.

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Malcolm D. Smith

Repatriation General Hospital

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Helen Weedon

Repatriation General Hospital

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Mark Coleman

Flinders Medical Centre

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Angela Parker

Repatriation General Hospital

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