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Biomedical subjects

P Dieppe

Publications and source records attributed to P Dieppe.

At least 19 recordsLinked to original sources
PubMed1997

Osteoarthritis in ankle and knee joints.

Ankle and knee joints differ in their susceptibility to osteoarthritis (OA). This article reviews literature on differences between these joints. A Medline search and search of bibliographies of review articles was conducted. Knee cartilage degeneration leads to the development of OA with clinical symptoms, whereas the ankle cartilage develops fissures that do not appear to progress to later stages of OA. Epidemiological studies support these findings. Factors that might explain this phenomena include differences in joint motion, cartilage thickness, congruency, mechanical forces, and even evolutionary changes. Data suggest that chondrocytes from the two joints may respond differently to stimuli. Comparisons of cartilage from the knee and ankle joint of the same donor may provide a better understanding of the biochemical and molecular processes that induce the pathogenesis of OA and may provide new approaches to early detection and treatment.

Ankle↗
PubMed1997

Bone formers: osteophyte and enthesophyte formation are positively associated.

OBJECTIVE: To test the hypothesis that enthesophyte formation and osteophyte growth are positively associated and to look for associations between bone formation at different sites on the skeleton so that a simple measure of bone formation could be derived. METHODS: Visual examination of 337 adult skeletons. All common sites of either enthesophyte or osteophyte formation were inspected by a single observer who graded bone formation at these sites on a 0-3 scale. The total score for each feature was divided by the number of sites examined to derive an enthesophyte and an osteophyte score. Cronbach's alpha and principal components analysis were used to identify groupings. RESULTS: Enthesophyte formation was associated with gender (M > F) and age. There was a positive correlation between enthesophytes and osteophytes (r = 0.65, 95% confidence interval, 0.58 to 0.71) which remained after correction for age and gender. Principal components analysis indicated four different groupings of enthesophyte formation. By choosing one site from each group a simple index of total skeletal bone formation could be derived. CONCLUSIONS: Osteophytes and enthesophytes are associated, such that a proportion of the population can be classified as "bone formers". Enthesophyte groupings provide some clues to aetiopathogenesis. Bone formation should be investigated as a possible determinant of the heterogeneity of outcome and of treatment responses in common musculoskeletal disorders.

Adult↗
PubMed1997

Quantitative magnetic resonance imaging of the knee: a method of measuring response to intra-articular treatments.

OBJECTIVES: To investigate the potential of quantitative magnetic resonance imaging (MRI) to differentiate between therapeutically induced changes in inflammation and synovial proliferation in rheumatoid arthritis (RA) of the knee. METHODS: MRI of the knee was performed on patients with RA before and one week after injection with corticosteroid (triamcinolone acetonide, TA group, n = 9) and before, four, and 12 weeks after injection with yttrium-90 plus TA (TA+Y group, n = 7). MRI scans were analysed by subjective visual grading by a trained observer and by computer aided quantitation for three features: synovial fluid volume, synovial pannus volume, and synovial enhancement after intravenous contrast agent. RESULTS: All TA subjects improved clinically at one week but the effects of TA+Y were more variable. TA significantly reduced synovial enhancement and effusion volume, whereas TA+Y at 12 weeks tended to increase synovial enhancement and decrease pannus volume. Quantitative MRI values agreed well with subjective assessment of scans. Comparison of calculated change on MRI scan before and immediately after aspiration with actual volume aspirated showed high correlation (r = 0.96). CONCLUSIONS: Quantitative MRI correlates with subjective visual assessment and, at least for synovial fluid, is accurate. MRI can differentiate actions of two therapeutic modalities on various pathological processes and is sensitive enough to detect change after one week. With the additional advantage of lack of observer bias, it will probably become a useful tool in the development and assessment of existing and novel treatments.

Adult↗
PubMed1996

Caring effects.

Explore the source record for details and available documents.

Adult↗
PubMed1996

Advantages of an increased dose of MRI contrast agent for enhancing inflammatory synovium.

MRI intravenous contrast enhancement of inflammatory synovium has been studied at two different doses to determine to what extent enhancement is dose dependent. 19 patients with clinically active rheumatoid arthritis involving a knee were scanned twice, one week apart, using 0.1 mmol/kg of gadoteridol (ProHance) on the first occasion and 0.3 mmol/kg on the second. Static pre-and post-contrast images together with dynamic images immediately following injection were obtained on a 1.0T scanner. On subjective assessment, 84% of patients showed improved enhancement. 47% showed more enhancing tissue, a clearer delineation of enhancing tissue or both. Objectively, enhancement was increased significantly at the higher dose, as judged by the percentage increase in mean signal intensity within regions of interest plotted over the suprapatellar pouch (1723% v. 1005% enhancement P < 0.05). In practical terms the better visualization of enhancing tissue achieved with higher doses is likely to reduce margins of error in attempts at quantification from MRI scans, particularly of synovial volume, but emphasizes also the need for care and consistency to be exercised in calculating the exact dose of contrast medium to be administered.

Adult↗
PubMed1996

Pain mechanisms in osteoarthritis of the knee: effect of intraarticular anesthetic.

OBJECTIVE: The causes of pain in osteoarthritis (OA) remain unclear. We examined the effect of intraarticular (IA) local anesthetic (LA) on pain perception in OA knee to test the hypothesis that pain arises from structures in contact with the intraarticular surface. The effect of intervention on one knee on perception of pain in the other was also studied. METHODS: Using a single blind, blind observer design, 20 subjects with bilateral symptomatic OA knee were randomized to receive either IA LA (bupivacaine 0.25%, 5 ml) or placebo into the most painful knee. Pain from both knees was assessed at 1 h, 24 h, and 7 days using a 100 mm visual analog scale (VAS). Pain descriptors using a standardized questionnaire (McGill) were recorded. RESULTS: At 1 h there was a significant fall in pain in LA knees (median VAS 61.5 to 0.0; p = 0.007). The change at VAS was significantly different between knees receiving LA and placebo (median change -45.5 vs +3.5; p = 0.03). 6/10 LA knees scored 0 on VAS at 1 h. Noninjected knees also showed a fall in pain scores. For knees contralateral to those receiving LA, the fall was from median 28.0 to 1.0 (p = 0.08). The reduction in pain was much less in knees contralateral to those receiving placebo (median 43.5 to 38.0), though the difference between the changes did not reach statistical significance. VAS scores remained below baseline for 7 days, though this difference was not significant. McGill pain scores fell in the LA group (for all categories of pain), but did not change in the placebo group. CONCLUSION: Pain in some cases of OA knee can be abolished by IA LA, suggesting that the structures responsible for pain are in contact with the intraarticular environment. As well, interventions in one knee have significant effects on pain perception in the contralateral knee.

Aged↗
PubMed1995

Serum hyaluronic acid level as a predictor of disease progression in osteoarthritis of the knee.

OBJECTIVE: To investigate the prognostic value of serum hyaluronic acid (HA) and keratan sulfate (KS) levels in relation to tibiofemoral osteoarthritis (OA) of the knee. METHODS: Clinical and demographic data were collected on 94 patients. Radiographs were obtained at study entry and at 5-year followup. Disease progression was defined as 2 mm of joint space narrowing of any tibiofemoral compartment, and/or knee joint surgery during the study period. Serum HA and KS were measured and levels were correlated with entry data and disease progression. RESULTS: At entry, HA levels were significantly related to disease duration (P = 0.036), minimum joint space (P = 0.049), and previous surgery (P = 0.001). After these variables were taken into account, patients whose disease had progressed were shown to have had significantly higher levels of HA at baseline compared with those whose disease had not progressed (P = 0.019). However, there were no significant differences in levels of serum KS between those with and those without disease progression, at entry (P = 0.779) or at subsequent visits. CONCLUSION: These results suggest that serum HA levels predict disease outcome in OA of the knee and confirm that a single measurement of the serum level of KS is not useful as a prognostic marker in OA.

Age Factors↗
PubMed1995

Evidence for a causal relationship between the structure, size, and load of calcium pyrophosphate dihydrate crystals, and attacks of pseudogout.

OBJECTIVE: To investigate any relationship between the nature, size, and numbers of synovial fluid (SF) calcium pyrophosphate dihydrate (CPPD) crystals, and attacks of pseudogout. METHODS: Knee SF was aspirated from nine selected patients, first during an attack of pseudogout (acute sample) and again later when the attack had subsided (interval sample). CPPD crystals were extracted, weighed, examined by high resolution transmission electron microscopy (HRTEM), and characterised by size and crystal habit (monoclinic or triclinic). Structural analysis was carried out by x ray powder diffraction (XRD) and the proportions of monoclinic to triclinic CPPD were estimated from densitometric measurements of selected key reflections. RESULTS: The mean crystal size, by HRTEM, indicated that the crystals in the acute sample were larger than those in the interval sample. The ratio of monoclinic to triclinic CPPD, whether estimated from their morphological appearance by HRTEM, or from XRD, was greater in the acute than in the interval sample in all nine patients. The total amount of extracted mineral varied, but in every patient the concentration of CPPD per ml of fluid, and the total mineral per joint, were greater in the acute sample than in the interval sample. CONCLUSION: In this highly selected group of patients, the large numbers of CPPD crystals associated with attacks of pseudogout included a greater proportion of monoclinic crystals, and larger crystals, than those present when inflammation had subsided. A special, phlogistic population of crystals may exist, originating in different joint tissues, or cleared in a different manner, than the more common populations of smaller crystals with a greater proportion of triclinic CPPD, seen in chronic disease.

Acute Disease↗
PubMed1995

Therapeutic targets in osteoarthritis.

Osteoarthritis (OA) can be considered as a disease process, amenable to therapy, or as a consequence of evolution, resulting in special disadvantages to long lived humans. Possible therapeutic targets are considered for both models of the condition. Targets for a disease process might include inhibition of tissue destruction, or the stimulation of natural repair processes. Therapeutic targets for the disadvantages of OA include novel approaches to the treatment of pain and physical disability. The 2 approaches are not mutually exclusive, and both should be pursued.

Disability Evaluation↗
PubMed1994

Taping the patella medially: a new treatment for osteoarthritis of the knee joint?

OBJECTIVE: To test the hypothesis that medial taping of the patella reduces the symptoms of osteoarthritis of the knee when the patellofemoral joint is affected. DESIGN: Randomised, single blind, crossover trial of three different forms of taping of the knee joint. Each tape (medial, lateral, or neutral) was applied for four days, with three days of no treatment between tape positions. SUBJECTS: 14 patients with established, symptomatic osteoarthritis of the knee and both clinical and radiographic evidence of patellofemoral compartment disease. MAIN OUTCOME MEASURES: Daily visual analogue scale ratings for pain; patients' rating of change with each treatment; and tape preference. RESULTS: Medial taping of the patella was significantly better than the neutral or lateral taping for pain scores, symptom change, and patient preference. The medial tape resulted in a 25% reduction in knee pain. CONCLUSION: Patella taping is a simple, safe, cheap way of providing short term pain relief in patients with osteoarthritis of the patellofemoral joint.

Aged↗
PubMed1994

Biological markers in rheumatoid arthritis.

Rheumatoid arthritis is characterized by chronic inflammation associated with considerable damage to the musculoskeletal system, particularly in and around diarthrodial joints. By using newly developed immunoassays and chemically based assays for cartilage-, bone-, and synovium-derived molecules, which are products of synthesis and/or degradation, it is now possible to detect the release of these molecules and their degradation products into body fluids such as serum, synovial fluid, and urine. This release is influenced significantly by the inflammatory process and reflects the damage caused to these tissues by chronic inflammation. Some new markers for skeletal metabolism are reviewed and examples are given of how they determine the damaging effects of this chronic inflammatory disease on these tissues before changes are observed radiologically. Some of these markers have both prognostic value and potential for rapidly interpreting the effects of therapy.

Aged↗