Rate of cartilage loss at two years predicts subsequent total knee arthroplasty: a prospective study

OBJECTIVE

To determine whether cartilage volume loss is an independent predictor of knee replacement.

DESIGN

Prospective community based, four year prospective cohort study.

METHODS

123 subjects with mild to moderate symptomatic radiographic knee osteoarthritis were recruited by either advertising, the Victorian branch of the Arthritis Foundation of Australia, treating general practitioners, orthopaedic surgeons, or rheumatologists; 113 completed the study. Magnetic resonance imaging was carried out at baseline and at 2 years on the symptomatic knee. Rate of change in tibial cartilage volume was calculated. Subjects were then followed up at year 4 to determine whether they had undergone a knee replacement.

RESULTS

The rate of tibial cartilage loss over two years was an independent predictor of knee replacement at four years. For every 1% increase in the rate of tibial cartilage loss there was a 20% increase risk of undergoing a knee replacement at four years (95% confidence interval, 10% to 30%). Those in the highest tertile of tibial cartilage loss had 7.1 (1.4 to 36.5) higher odds of undergoing a knee replacement than those in the lowest tertile. WOMAC score at baseline, female sex, and tibial bone size (but not age and radiographic score) were also predictors of knee replacement.

CONCLUSIONS

The data suggest that treatment targeted at reducing the rate of knee cartilage loss in subjects with symptomatic osteoarthritis may delay knee replacement. This has important implications in terms of prevention and therapeutic interventions in osteoarthritis.

Early radiographic osteoarthritis is associated with substantial changes in cartilage volume and tibial bone surface area in both males and females

OBJECTIVE

To describe the association between early radiographic osteoarthritis of the knee (ROA), knee cartilage volume and tibial bone surface area.

METHODS

Cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61). Articular cartilage volume, bone area and volume were determined at the patella, medial tibial and lateral tibial compartments by processing images acquired in the sagittal plane using T1-weighted fat saturation MRI. ROA was assessed with a standing semiflexed radiograph and the OARSI atlas for joint space narrowing and osteophytosis. Both radiographs and MRIs were performed in the right knee and read by different observers.

RESULTS

ROA (predominantly grade 1) was present in 17% of subjects of which medial joint space narrowing was most common (14%) followed by medial osteophytes (6%). Grade one medial joint space narrowing was associated with substantial reductions in cartilage volume at both the medial and lateral tibial and patellar sites within the knee (adjusted mean difference 11-13%, all P<0.001) while grade one osteophytosis was associated with substantial increases in both lateral and medial tibial joint surface area (adjusted mean difference 10-16%, all P<0.001). In contrast, osteophytosis was not associated with a significant change in cartilage volume and joint space narrowing was not associated with a significant change in tibial bone area (all P>0.05).

CONCLUSIONS

Early medial compartment ROA is associated with substantial reductions in cartilage volume and increases in bone area. These large changes, when combined with similar measurement error for MRI and radiographs, suggest that MRI may be superior at detecting and hence understanding early osteoarthritis of the knee in humans.

Q2 evolution of the neutron spin structure moments using a 3He target

We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)[2g(1)(x,Q2)+3g(2)(x,Q2)]dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.

A systematic genomewide linkage study in 353 sib pairs with schizophrenia

We undertook a genomewide linkage study in a total of 353 affected sib pairs (ASPs) with schizophrenia. Our sample consisted of 179 ASPs from the United Kingdom, 134 from Sweden, and 40 from the United States. We typed 372 microsatellite markers at approximately 10-cM intervals. Our strongest finding was a LOD score of 3.87 on chromosome 10q25.3-q26.3, with positive results being contributed by all three samples and a LOD-1 interval of 15 cM. This finding achieved genomewide significance (P<.05), on the basis of simulation studies. We also found two regions, 17p11.2-q25.1 (maximum LOD score [MLS] = 3.35) and 22q11 (MLS = 2.29), in which the evidence for linkage was highly suggestive. Linkage to all of these regions has been supported by other studies. Moreover, we found strong evidence for linkage (genomewide P<.02) to 17p11.2-q25.1 in a single pedigree with schizophrenia. In our view, the evidence is now sufficiently compelling to undertake detailed mapping studies of these three regions.

Sex differences in knee cartilage volume in adults: role of body and bone size, age and physical activity

OBJECTIVE

To test the hypothesis that sex differences in knee cartilage volume may be mediated through body and bone size, age and/or physical activity.

METHODS

A cross-sectional convenience sample of 372 subjects (males 43%; mean age 45 yr, range 26-61) was studied. Articular cartilage volumes and bone size were determined at the patella, medial and lateral tibia by processing images acquired in the sagittal plane using T1-weighted fat saturation magnetic resonance imaging. Height, weight, physical activity (lower limb muscle strength, endurance fitness and questionnaire items) and radiographic osteoarthritis (ROA) were measured.

RESULTS

Gender explained 33-42% of the variation in knee cartilage volumes (all P < 0.001). Males had 33-42% higher cartilage volume than females at all sites. In the whole group, the magnitude of sex differences decreased to 8-18% after adjustment for body height, weight and bone size, but remained significant (all P < 0.05). Further adjustment for physical activity had no effect on the sex differences. The sex differences in cartilage volume were greater in those aged over 50 compared with those aged under 50 (P < 0.05 for age-sex interaction at all sites) and were independent of ROA.

CONCLUSIONS

Men have substantially higher knee cartilage volumes than women. These sex differences appear to be mediated in part by body and bone size but a significant amount remains unexplained. Furthermore, the differences become more marked over the age of 50 yr suggesting that both cartilage development and cartilage loss in later life contribute to sex differences in cartilage volume. Further longitudinal studies in large samples will be required to confirm these findings.

Interpreting change scores on the Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40)

OBJECTIVES

To determine the amount of change over time on the five dimensions of the 40-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) that are subjectively meaningful to patients. Minimally important differences (MID), effect sizes (ES) and standardized response means (SRM) are calculated for respondents who indicate only a little change over the time of the study whilst mean change scores, ES and SRM statistics are calculated for those who indicated much change.

DESIGN

Postal survey. Copies of the ALSAQ-40 were completed on two occasions three months apart. Respondents were also asked to indicate how much change they had experienced since baseline on each of the five domains of the questionnaire.

SETTING

All patient members of the Motor Neurone Disease Association for England, Wales and Northern Ireland.

SUBJECTS

Seven hundred and sixty-four patient members returned questionnaires at baseline and follow-up.

RESULTS

For those reporting minor change since baseline results varied across dimensions. For example a MID was reflected in a change of 6.67 (SD 16.52) points for the Communication dimension, whilst for the Emotional functioning dimension the change was 2.67 (SD 15.45) points. Similarly ESs and SRMs varied considerably across dimensions. Mean change over time, ES and SRM statistics for those who reported that their health was much worse at follow-up were substantially larger: for example, mean changes ranged from 6.87 (SD 15.87) to 13.79 (SD 22.60).

CONCLUSIONS

Results indicate the minimum magnitude of change that is subjectively meaningful to patients. Results indicate that smaller changes than have been suggested previously as significant have a subjectively meaningful adverse effect upon patients.

Mutation screening of the Homer gene family and association analysis in schizophrenia

Homer proteins are a group of proteins that regulate group 1 metabotropic glutamate receptor function. As altered glutamate function has been implicated in many neuro psychiatric disorders, particularly schizophrenia, we have screened all three known Homer genes for sequence variation for use under the candidate gene association paradigm. We found seven SNPs, including three in exons. Of these, none was non-synonymous. Allele frequencies of all the detected SNPs were estimated in DNA pools of 368 schizophrenics and 368 controls. Only one (Homer 1 IVS4 + 18A > G) was associated with schizophrenia in this sample, a finding confirmed by individual genotyping (P = 0.01). However, in our extended sample of 680 cases and 671 controls, the evidence for association diminished (P = 0.05). Our results suggest it is unlikely that sequence variants in the Homer genes contribute to the aetiology of schizophrenia, but the variants we identified are plausible candidates for other neuropsychiatric phenotypes.

Adipose thyrotrophin receptor expression is elevated in Graves' and thyroid eye diseases ex vivo and indicates adipogenesis in progress in vivo

The thyrotrophin receptor (TSHR) provides an autoantigenic link between the thyroid and orbit in Graves' (GD) and thyroid eye diseases (TED). We measured TSHR transcripts in different fat depots to determine whether TSHR expression levels are influenced by the autoimmune/inflammatory process and/or thyroid hormone status, using quantitative real-time PCR. Nine intact or fractionated adipose samples, from patients with GD and/or TED, were analysed ex vivo. Eight expressed the TSHR, at levels approaching the thyroid, and one was at the limit of detection. Thirteen/fifteen orbital and abdominal fat samples from patients free of GD and TED, measured ex vivo, were negative for TSHR transcripts and two were at the limit of detection. All preadipocyte samples induced to differentiate in vitro expressed the TSHR. To investigate the influence of thyroid hormone status on adipose TSHR expression, we induced hyper- and hypothyroidism in BALBc mice by administering tri-iodothyronine and propylthiouracil respectively. In euthyroid animals, whole fat samples were at the limit of detection and were not altered by thyroid hormone status. The results show that adipose TSHR expression ex vivo indicates adipogenesis in progress in vivo and is associated with the autoimmune/inflammatory process in GD and TED but is not restricted to the orbit or influenced by thyroid hormone status.

Oral administration of type II collagen suppresses pro-inflammatory mediator production by synoviocytes in rats with adjuvant arthritis

The objective of this study was to investigate the effect of the oral administration of type II collagen (CII) on pro-inflammatory mediator production by synoviocytes in rats with adjuvant arthritis (AA). Sprague-Dawley rats were fed with bovine CII either before immunization with Complete Freund's adjuvant (CFA) or after initiation of arthritis. Hind paw secondary swelling was measured and synoviocytes were harvested. Sera from portal vein of oral tolerized rats were collected and in vitro synoviocytes culture or synoviocytes-Peyer's Patches (PP) cells coculture system were developed. Interleukin (IL)-1 activity was measured by a mouse thymocyte activation assayed by MTT dye reduction and tumour necrosis factor (TNF) activity was measured by an L929 cytotoxicity bioassay. Nitric oxide (NO) and malondialdehyde (MDA) levels were measured by biochemical methods. We found that feeding with CII (5, 50 and 500 micro g/kg) for 7 days before immunization significantly suppressed hind paw secondary swelling measured at day 16, 20, 24 and 28 (all P < 0.01) and pro-inflammatory mediator (IL-1, TNF, NO and MDA) production by synoviocytes (all P < 0.01) in rats with AA. Feeding with CII (5, 50 and 500 micro g/kg) for 7 days after initiation of arthritis had a similar effect. CII (1, 10, 100 micro g/ml) had no effect on IL-1 and TNF production by synoviocytes in vitro, but CII 10 micro g/ml suppressed IL-1 and TNF production by synoviocytes-PP cells coculture system (P < 0.01), which was antagonized by anti-TGF-beta antibody (10 micro g/ml) (P < 0.01). Portal serum (1 : 10) from oral tolerized rats suppressed IL-1 and TNF production by synoviocytes (P < 0.01), which was also antagonized by anti-TGF-beta antibody (10 micro g/ml) (P < 0.01). We conclude that oral administration of CII had prophylactic and therapeutic effects on AA and over-production of IL-1, TNF, NO and MDA by synoviocytes was suppressed. Bystander active suppression may be the main mechanism of oral CII in the suppression of synoviocyte function.

Quadriceps voluntary activation at different joint angles measured by two stimulation techniques

People are able to fully activate their quadriceps at mid-length during a brief isometric contraction but it is uncertain whether this is the case at other muscle lengths. With the twitch superimposition technique for determining levels of voluntary activation (VA), the muscle may be stimulated through the intramuscular branches of the nerve or via the nerve trunk itself. The former technique is easier to use, but different populations of motor units may be stimulated if the joint position is changed to alter muscle length. The purpose of this study was to investigate quadriceps VA at a range of knee joint angles using both magnetic stimulation of the motor nerve and percutaneous electrical stimulation over the muscle belly. Eight healthy subjects (six females, mean age 29 years) performed maximal voluntary contractions of the quadriceps at knee joint angles at 10-110 degrees of flexion. Surface electromyography (EMG) of quadriceps and hamstrings was recorded as an indication of the amount of muscle activity. Nearly all subjects showed >95% VA at all joint angles. VA did not vary with joint angle nor were there significant differences between the two stimulation techniques. Similarly, there was no significant effect of knee joint angle on the EMG activity of either muscle group. These findings indicate that VA of the quadriceps during a brief isometric contraction is not affected by muscle length and can be measured by either stimulation technique.

Histopathological biomarkers in estuarine fish species for the assessment of biological effects of contaminants

The increasing emphasis on the assessment and monitoring of estuarine ecosystems has highlighted the need to deploy appropriate biological indices for these locations. Fish diseases and histopathology, with a broad range of causes, are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of historical exposure. This study reports on the histopathological alterations observed in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde), differently impacted by contaminants, including PAHs. A biannual sampling regime was used to identify the important seasonal variations that occur in terms of the observed biological effects. Inflammatory lesions and hepatocellular fibrillar inclusions attained their highest prevalence in P. flesus captured from the Tyne, Tees and Mersey. The presence of pre-neoplastic and neoplastic toxicopathic lesions was highest in P. flesus captured from these sites, when compared to fish from the Aide reference site. In particular, the prevalence of hepatic foci of cellular alteration (up to 43.3%) and hepatocellular adenoma (up to 10%) were highest in P. flesus captured from the Mersey estuary. Intersex (ovotestis) was only recorded in male P.flesus captured from the Mersey estuary (up to 8.3%) and from male Z. viviparous captured from the Tyne estuary (25%). Pathologies associated with the gill and the kidney were also most prevalent in fish captured from the Tyne, Tees and Mersey estuaries. This study has successfully applied histopathology to an estuarine monitoring program, both for the recording of toxicopathic lesions in the liver and other organs, and for the detection of the endpoint of endocrine disruption, intersex. As such, it provides a powerful integrative tool for the assessment of biological effects of contaminants in these environments.

A randomized controlled trial of phytoestrogen supplementation, growth and bone turnover in adolescent males

OBJECTIVE

To assess the effect of phytoestrogens on bone turnover and growth in adolescent boys.

DESIGN

Randomized double-blind placebo-controlled trial.

SETTING

Single school in northwest Tasmania.

PARTICIPANTS

Adolescent boys (treatment n=69, placebo n=59, mean age 16.8 y).

INTERVENTIONS

Six weeks of isoflavone supplementation (Novasoy, 50 mg daily of isoflavone equivalents). Bone turnover markers (bone specific alkaline phosphatase (BAP) and pyridinoline creatinine ratio (PYR)) were measured at baseline and follow-up.

RESULTS

Despite marked increases in urinary genistein and daidzein in the treatment arm (both P<0.001), there were no significant differences in BAP, PYR or short-term height or weight change. This applied to both intention-to-treat and per protocol analysis. Neither was there a significant correlation between urinary genistein and daidzein levels and BAP or PYR.

CONCLUSIONS

Phytoestrogen supplementation to the level of usual Japanese dietary intake has no measurable effect on bone turnover in adolescent boys. Longer-term studies of bone density may be desirable but it is unlikely that there will be a large effect in either girls or boys given the lower endogenous oestrogen levels in boys.