A rheumatologist's perspective on musculoskeletal ultrasound in rheumatology: comment on the editorial by Roemer et al.
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Biomedical subjects
Publications and source records attributed to David Kane.
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BACKGROUND: Monoclonal antibodies are used extensively throughout the biomedical sciences for detection of antigens, either in vitro or in vivo. We, for example, have used them for quantitation of proteins on "reverse-phase" protein lysate arrays. For those studies, we quality-controlled > 600 available monoclonal antibodies and also needed to develop precise information on the genes that encode their antigens. Translation among the various protein and gene identifier types proved non-trivial because of one-to-many and many-to-one relationships. To organize the antibody, protein, and gene information, we initially developed a relational database in Filemaker for our own use. When it became apparent that the information would be useful to many other researchers faced with the need to choose or characterize antibodies, we developed it further as AbMiner, a fully relational web-based database under MySQL, programmed in Java. DESCRIPTION: AbMiner is a user-friendly, web-based relational database of information on > 600 commercially available antibodies that we validated by Western blot for protein microarray studies. It includes many types of information on the antibody, the immunogen, the vendor, the antigen, and the antigen's gene. Multiple gene and protein identifier types provide links to corresponding entries in a variety of other public databases, including resources for phosphorylation-specific antibodies. AbMiner also includes our quality-control data against a pool of 60 diverse cancer cell types (the NCI-60) and also protein expression levels for the NCI-60 cells measured using our high-density "reverse-phase" protein lysate microarrays for a selection of the listed antibodies. Some other available database resources give information on antibody specificity for one or a couple of cell types. In contrast, the data in AbMiner indicate specificity with respect to the antigens in a pool of 60 diverse cell types from nine different tissues of origin. CONCLUSION: AbMiner is a relational database that provides extensive information from our own laboratory and other sources on more than 600 available antibodies and the genes that encode the antibodies' antigens. The data will be made freely available at http://discover.nci.nih.gov/abminer.
Alternative RNA splicing greatly increases proteome diversity and may thereby contribute to tissue-specific functions. We carried out genome-wide quantitative analysis of alternative splicing using a custom Affymetrix microarray to assess the role of the neuronal splicing factor Nova in the brain. We used a stringent algorithm to identify 591 exons that were differentially spliced in the brain relative to immune tissues, and 6.6% of these showed major splicing defects in the neocortex of Nova2-/- mice. We tested 49 exons with the largest predicted Nova-dependent splicing changes and validated all 49 by RT-PCR. We analyzed the encoded proteins and found that all those with defined brain functions acted in the synapse (34 of 40, including neurotransmitter receptors, cation channels, adhesion and scaffold proteins) or in axon guidance (8 of 40). Moreover, of the 35 proteins with known interaction partners, 74% (26) interact with each other. Validating a large set of Nova RNA targets has led us to identify a multi-tiered network in which Nova regulates the exon content of RNAs encoding proteins that interact in the synapse.
Modulation by proinflammatory mediators indicate that NURR1 induction represents a point of convergence of distinct signaling pathways, suggesting an important common role for this transcription factor in mediating multiple inflammatory signals. The present study identifies NURR1 as a molecular target of methotrexate (MTX) action in human inflammatory joint disease and examines the mechanism through which MTX modulates NURR1 expression. MTX significantly suppresses expression of NURR1 in vivo in patients with active psoriatic arthritis (n = 10; p < 0.002) who were prescribed low-dose MTX for management of peripheral arthritis. Importantly, reduction in NURR1 levels correlate (n = 10; r = 0.57; p = 0.009) with changes in disease activity score (both clinical and laboratory parameters). MTX selectively modulates NURR1 levels induced by inflammatory stimuli and growth factors in resident cell populations of synovial tissue. In primary human synoviocytes and microvascular endothelial cells, we observe dose-dependent differential effects of MTX on steady-state and inducible NURR1 levels. Our data confirms that adenosine, and its stable analog 5'-N-ethylcarboxamideadenosine, can mimic the differential effects of MTX on NURR1 transcription. In addition, we verify that the inhibitory effect of low-dose MTX on NURR1 activation is mediated through the adenosine receptor A2. More specifically, our data distinguishes the selective involvement of the A2A receptor subtype in these responses. In summary, these findings establish the nuclear orphan receptor NURR1 as a molecular target of MTX action in human inflammatory joint disease and demonstrate that the immunomodulatory actions of MTX on NURR1 expression are mediated through adenosine release.
Psoriatic arthritis (PsA) presents many diagnostic, management and research challenges for rheumatologists who wish to obtain early diagnosis, differentiate synovitis and enthesitis, monitor disease activity accurately and objectively, prevent the development of structural damage, deliver local therapy accurately, and obtain PsA tissue for research purposes. Musculoskeletal ultrasound (MSUS) is widely used by European rheumatologists in their clinical practice to meet these challenges and has the potential to become the rheumatologist's stethoscope in Europe and North America. This paper examines the evidence that MSUS can improve clinical evaluation of patients with PsA for synovitis and enthesitis, that MSUS is more sensitive than plain radiography in detecting structural damage in joints, that MSUS can improve the success of joint aspiration and guide biopsy of PsA tissues. Recent exciting developments in the management of PsA are detailed including the role of power Doppler in the diagnosis of enthesitis in PsA, the role of MSUS in objective monitoring of disease activity, the evaluation of MSUS in the diagnosis of sacroiliitis, and the use of MSUS to guide therapeutic injection of the sacroiliac joints.
In the majority of patients with psoriatic arthritis (PsA), it is a chronic progressive disease, and only 12% of patients with early PsA will be in disease-modifying antirheumatic drug-free remission at 2 years. Radiologic damage occurs in the early stages of PsA; up to 47% of patients with PsA have radiologic erosions after 2 years. This article reviews the clinical features of early PsA, pathologic insights into PsA gleaned from studies of early PsA, and the current state of diagnostic imaging and therapeutics in early PsA.
Ultrasound (US) has great potential as an outcome in rheumatoid arthritis trials for detecting bone erosions, synovitis, tendon disease, and enthesopathy. It has a number of distinct advantages over magnetic resonance imaging, including good patient tolerability and ability to scan multiple joints in a short period of time. However, there are scarce data regarding its validity, reproducibility, and responsiveness to change, making interpretation and comparison of studies difficult. In particular, there are limited data describing standardized scanning methodology and standardized definitions of US pathologies. This article presents the first report from the OMERACT ultrasound special interest group, which has compared US against the criteria of the OMERACT filter. Also proposed for the first time are consensus US definitions for common pathological lesions seen in patients with inflammatory arthritis.
OBJECTIVE: Methotrexate is one of the most commonly used disease-modifying antirheumatic drugs in the management of psoriatic arthritis (PsA). Despite the differences between the inflammation in PsA and rheumatoid arthritis (RA), the effects of methotrexate on the synovium have been described solely in RA. In this study, we sought to determine the effects of methotrexate on the inflammatory infiltrate and on cytokine and metalloproteinase gene expression in the synovium of PsA patients. METHODS: Ten patients with PsA (median duration 18 months) underwent arthroscopy and synovial biopsy of an inflamed knee before and after clinical improvement induced by methotrexate. Immunohistologic analysis was performed using antibodies to CD3, CD4, CD8, CD68, factor VIII, vascular cell adhesion molecule, E-selectin, and intercellular adhesion molecule (ICAM). Matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of metalloproteinases 1 (TIMP-1) messenger RNA (mRNA) were quantified by competitive reverse transcription-polymerase chain reaction (RT-PCR). Interleukin-1alpha (IL-1alpha), IL-1beta, IL-2, IL-4, IL-5, IL-8, IL-10, IL-12p35, IL-12p40, IL-15, interferon-gamma (IFNgamma), and tumor necrosis factor alpha (TNFalpha) mRNA expression was quantified by real-time PCR. RESULTS: Patients received a median methotrexate dosage of 13.75 mg/week (range 7.5-15) for a median of 11.5 months (range 7-14 months). The Ritchie Articular Index, swollen joint count, and Disease Activity Score were significantly reduced. There was a decrease in all immunohistologic staining, although this was statistically significant only for CD3, CD4, CD8, CD68, E-selectin, and ICAM. Despite clinical improvement in all patients, there was a residual T cell infiltrate in all synovial biopsy tissues. The synovial lining layer thickness, but not hypervascularity, was significantly reduced. There was also a significant reduction in MMP-3, but not TIMP-1, expression. Before treatment, PsA synovium was characterized by a predominant expression of the proinflammatory cytokines IL-15, IFNgamma, IL-1beta, and TNFalpha and the antiinflammatory cytokine IL-10. Methotrexate reduced synovial IL-1alpha, IL-1beta, IL-8, IL-10, IL-15, IFNgamma, and TNFalpha mRNA expression, but the effect was significant only for IL-8. CONCLUSION: Methotrexate produced a clinical response in PsA by reducing, but not abolishing, the inflammatory infiltrate, adhesion molecule expression, and MMP-3 and proinflammatory cytokine gene expression, particularly IL-8, in the synovium. Methotrexate did not reduce hypervascularity, which is a prominent differentiating feature of PsA synovium.
The successful introduction of anti-tumor necrosis factor (TNF) therapies in psoriasis and psoriatic arthritis has sharpened considerable interest in this chronic and frequently disabling disease. Unlike the situation in rheumatoid arthritis, where anti-TNF therapies were introduced after years of painstaking research which confirmed a key proinflammatory role for TNF, the evidence for TNF having a key role in psoriatic arthritis has lagged behind. In this paper, the emerging immunohistochemical, genetic, and clinical literature relating to TNF's role in skin and joint manifestations of this disease is reviewed and areas for future research are suggested.
The fate of anthropogenic substances in the environment is increasingly determined using multimedia mass balance models. It is, therefore, critical to fully understand how such models work and what their limitations are. The effects of uncertainty and variation in the chemical properties, discharges, and landscape parameters on model outcome have been examined by other researchers. Here, the role of landscape properties in controlling region-to-region differences in chemical fate is examined. Specifically, regions of Canada and the ChemCAN model are used to explore the region-to-region difference in fate for benzo[a]pyrene, hexachlorobenzene, tetrachloroethylene, alpha-hexachlorocyclohexane, 2,2',5,5'-tetrachlorobiphenyl (PCB 52), and atrazine emitted individually to air, water, and soil. To facilitate the same analysis in other places a description of the model and the methods for obtaining the landscape parameters used here are given. Differences in fate are the unique result of combining the input parameters of chemical properties, emission data, and landscape parameters. While region-to-region differences are small compared to the chemical-to-chemical differences that may span many orders of magnitude for physical-chemical or degradation properties, chemical fate is not the same for regions of differing landscape parameters. It is therefore concluded that the quality of results obtained from regional environmental fate models can be improved by the use of region-specific landscape parameters.
OBJECTIVE: The distinct and different patterns of radiological damage in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) may be a product of the relative balance of proteolytic enzyme and inhibitor gene expression in synovial tissue. This study compared metalloproteinase gene expression in synovium located proximal to the cartilage-pannus junction (CPJ) and distal to the CPJ (non-CPJ) in patients with PsA and RA. METHODS: Synovial biopsies were obtained from CPJ and non-CPJ sites under direct vision at arthroscopy of an inflamed knee in patients with PsA (n = 12) and RA (n = 12) who were not under disease modifying antirheumatic drug treatment. A competitive, quantitative RT-PCR technique was established for synovial RNA using a polycompetitor construct containing mRNA-specific primer sites for collagenase (MMP-1), stromelysin (MMP-3), tissue inhibitor of metalloproteinase-1 (TIMP-1), and GAPDH. cDNA products were separated and quantified by ethidium bromide stained gel electrophoresis and mRNA values were normalized relative to GAPDH expression. RESULTS: MMP-1, MMP-3, and TIMP-1 mRNA were upregulated in RA and PsA synovium with a prodestructive (MMP-1 + MMP-3)/TIMP-1 balance in both diseases. Similar levels of MMP mRNA expression were observed in PsA and RA despite the presence of less radiological erosion in the PsA group. No difference was observed in the degree of upregulation of MMP-1, MMP-3, or TIMP-1 mRNA in paired biopsies from CPJ and non-CPJ sites in either PsA (n = 8) or RA (n = 10). The ratio of TIMP-1 expression in CPJ compared to non-CPJ biopsies was higher in patients with nonerosive disease (10.1 +/- 27.8) than in erosive patients (0.75 +/- 0.27; p = 0.07). CONCLUSION: PsA and RA have similar levels of MMP-1, MMP-3, and TIMP-1 mRNA expression in synovium. There is no evidence of increased metalloproteinase mRNA expression at the CPJ in RA or PsA. The different patterns of radiological progression seen in RA and PsA were not explained by differences in synovial mRNA expression of MMP-1, MMP-3, or TIMP-1.
MatchMiner is a freely available program package for batch navigation among gene and gene product identifier types commonly encountered in microarray studies and other forms of 'omic' research. The user inputs a list of gene identifiers and then uses the Merge function to find the overlap with a second list of identifiers of either the same or a different type or uses the LookUp function to find corresponding identifiers.
OBJECTIVE: To determine whether functional cytokine gene polymorphisms influence disease susceptibility and phenotype in patients with psoriatic arthritis (PsA). METHODS: DNA was obtained from 147 PsA patients and 389 controls. Seven functional proinflammatory (interleukin-1beta [IL-1beta] +3953, IL-6 -174, tumor necrosis factor alpha [TNFalpha] -308, TNFbeta +252) and antiinflammatory (IL-10 -1082, IL-10 -592, IL-1 receptor antagonist [intron 2, 86 bp, variable-number tandem repeat]) gene polymorphisms were detected by polymerase chain reaction and restriction fragment length polymorphism assays. RESULTS: No significant difference in genotype frequencies was observed between the control and the PsA patient populations, and no association with Steinbrocker functional class, disease classification (polyarticular or oligoarticular), presence of spinal involvement, or age at PsA onset was observed. The presence of joint erosions was significantly associated with the TNFalpha -308 and TNFbeta +252 polymorphisms (P < 0.0001 and P = 0.0017, respectively). Frequencies of the TNFalpha -308 and TNFbeta +252 genotypes were also significantly different (P = 0.0078 and P = 0.0486, respectively) in a group of progressors (patients with early PsA in whom the number of joint erosions in the hands and feet increased over a median interval of 24 months) compared with a group of nonprogressors. Age at psoriasis onset was significantly associated with the TNFbeta +252 and TNFalpha -308 polymorphisms (P = 0.0003 and P = 0.0081, respectively). The TNFB2B2 and TNFalpha -308 AA genotypes were associated with the earliest mean ages at psoriasis onset. CONCLUSION: The TNFalpha -308 and TNFbeta +252 polymorphisms were significantly associated with age at psoriasis onset, presence of joint erosions in PsA, and progression of joint erosions in early PsA. TNF gene polymorphisms may be useful prognostic markers in PsA, and these results support the rationale for using anti-TNF treatment in patients with severe, progressive PsA.
OBJECTIVE: To analyze S-100 protein expression, in the form of myeloid-related protein 8 (MRP8), MRP14, and the heterodimer MRP8/MRP14, in psoriatic arthritis (PsA) patients compared with rheumatoid arthritis (RA) and spondylarthropathy (SpA) patients, and to determine the effect of methotrexate (MTX) on the MRP antigen expression in PsA patients. METHODS: Serum, synovial fluid (SF), and synovium (taken at arthroscopy) samples were obtained from PsA (before and after MTX treatment), RA, and SpA patients. Concentrations of MRP8/MRP14 in serum and SF were measured by enzyme-linked immunosorbent assay. Expression of MRP8, MRP14, and MRP8/MRP14 in synovium was determined by immunohistochemistry. RESULTS: MRP8, MRP14, and MRP8/MRP14 levels were increased in serum, SF, and synovium from PsA, RA, and SpA patients. In all 3 groups, paired samples of serum and SF showed significantly higher MRP8/MRP14 levels in SF (mean +/- SD 15310 +/- 16999 ng/ml [median 11400]) than in serum (908 +/- 679 ng/ml [median 695]) (P = 0.0001). MRP8/MRP14 levels in serum correlated with systemic parameters of disease activity (erythrocyte sedimentation rate [ESR] r = 0.55, P = 0.005; C-reactive protein [CRP] level r = 0.55, P = 0.005), whereas levels in SF correlated with local parameters of disease activity (white blood cell count r = 0.45, P = 0.01; acute-phase serum amyloid A level r = 0.32, P = 0.03). MRP expression was significantly higher in the synovial sublining layer (SLL) of PsA patients compared with RA and SpA patients. MRP antigens were predominantly expressed in perivascular areas of the SLL in PsA patients. Following MTX treatment, MRP expression in serum and synovium from PsA patients was significantly reduced. Serum levels of MRP were more sensitive to the effects of MTX than were the ESR, CRP, or clinical joint scores. CONCLUSION: MRP levels in serum and SF correlate with local and systemic inflammation and are equally increased in PsA, RA, and SpA patients. In contrast, MRP8, MRP14, and MRP8/MRP14 expression in the SLL of PsA patients is increased, particularly in perivascular regions, compared with that in RA and SpA patients, suggesting a central role of MRP proteins in transendothelial migration of leukocytes in PsA. Moreover, MRP expression is reduced following MTX treatment. MRP proteins may represent a novel therapeutic target in inflammatory arthritis.
The concentration and glycosylation of alpha(1)-acid glycoprotein (AGP) alter significantly during inflammation. A definitive physiological role for AGP remains elusive and is the subject of extensive investigation. This study investigated the influence of AGP on the activity of collagenase-3, an important mediator of cartilage destruction in rheumatoid arthritis. AGP was isolated from normal and rheumatoid plasma. Fucosylation was determined by high pH anion-exchange chromatography; sialylation was assessed following enzymatic digest. Rheumatoid AGP displayed elevated fucosylation and sialylation compared with normal. The influence of each sample on collagenase-3 activity was measured fluorometrically. AGP influenced collagenase-3 catalysis and collagen binding, with catalytic activity correlating with fucosylation. Rheumatoid AGP exhibited less efficient inhibition than normal plasma AGP. It is hypothesized that AGP within rheumatoid synovial fluid may be inadequate to prevent excessive cartilage destruction and hence may exacerbate the disease process.
OBJECTIVE: Musculoskeletal ultrasonography allows real-time imaging of joint structures and may be used to complement clinical examination in rheumatological practice. We compared ultrasonography (US) with clinical examination (CE) in the detection of effusion, suprapatellar bursitis, and Baker's cyst of the knee in rheumatoid arthritis (RA) in order to determine whether US provided additional clinical information. METHODS: A total of 22 patients with RA (ACR criteria) underwent independent clinical and US examination of both knees for suprapatellar bursitis, knee effusion, and presence of Baker's cyst. US was performed using an ATL HDI 3000 machine with L7-4 MHz and CL10-5 MHz probes. Clinical examination was performed using standard techniques by an experienced rheumatologist. Patients with previous knee surgery were excluded from the study. RESULTS: A total of 44 knees were examined at a total of 130 sites (one patient was unable to lie prone for US of popliteal fossae). US detected soft tissue abnormality (suprapatellar bursitis, knee effusion, or Baker's cyst) at 54/130 (42%) sites, while CE detected soft tissue abnormality at 36/130 (28%) sites. US detected 17 (39%) cases of suprapatellar bursitis in 44 knees, 7 (16%) of which were detected on CE. US detected 27 (61%) knee joint effusions in 44 knees, 16 (36.36%) of which were detected on CE. US detected 10 (23.81%) Baker's cysts in 42 knees, 2 (4.76%) of which were detected on CE. Taking US of the knee as the gold standard, CE was specific but not sensitive in the detection of soft tissue abnormality of the knee in RA. CONCLUSION: US is more sensitive than CE in the detection of suprapatellar bursitis, knee effusion, and Baker's cyst in RA. CE underestimates knee inflammation in RA. This has implications for the use of CE as a component of standardized disease activity scores and in guiding knee joint aspiration.
This study investigates the effect of alpha(1)-acid glycoprotein (AGP) isolated from both normal and rheumatoid plasma on type II collagen fibril formation. Rheumatoid samples were obtained over 2 years from two patients with early arthritis. The glycosylation of each sample was analysed to establish any correlation with fibrillogenesis. Rheumatoid AGP displays increased fucosylation compared to normal AGP. In both patients the fucosylation dipped after 1 year, then rose again over year 2. It is proposed that year 1 corresponds to the acute phase of the disease and the onset of chronic inflammation after this time produces a subsequent increase in fucosylation. Rheumatoid AGP influences type II collagen fibrillogenesis. Native fibrils were produced but with differences in the rate and extent of fibrillogenesis depending on AGP concentration and fucosylation. Low concentrations produced a decrease in fibrillogenesis rate and fibril diameter. High concentrations produced fibrils at a rate and diameter dependent on fucosylation. Highly fucosylated AGP produced narrow fibrils slowly, whereas poorly fucosylated AGP produced thicker fibrils more quickly. We propose that differences in glycosylation (especially fucosylation) of AGP are responsible for differences in collagen fibrillogenesis and this phenomenon may contribute to the exacerbation of cartilage destruction in rheumatoid arthritis.
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