Probing motor dynamics at the muscle level-Acoustic myography in Parkinson's disease

Acoustic myography (AMG) noninvasively probes muscle activity. We explored whether AMG captures abnormal motor activity in patients with Parkinson's disease (PD) and how this activity is modulated by antiparkinsonian medication. Twenty patients with PD underwent AMG of the biceps, triceps, extensor carpi radialis longus, and adductor policis muscles of the more affected arm during active and passive movements, using a mobile AMG device (CURO, Denmark). AMG and assessment of motor symptoms were performed in a pragmatic off-medication state, as well as one and 3 h after oral intake of 200 mg levodopa. Three AMG parameters were calculated using the CURO analysis system. Motor efficiency was expressed by the E-score, muscle fiber recruitment by the temporal T-score, spatial summation by the S-score, and S/T ratio. Twenty age- and sex-matched healthy subjects served as controls. Group mean values were statistically compared using unpaired two-tailed adjusted t-test and ANOVA with Tukey´s correction for multiple comparison (p ≤ 0.05). For the biceps and extensor carpi radialis longus muscles, the active movement S:T ratio was lower in PD relative to healthy controls. The E-score was also lower during active and passive flexion/extension movements in the off-medication state. No significant between-group differences in the AMG scores were noted for the triceps muscle during active or passive movements. The active S:T ratio and the E-score during active elbow flexion and extension may offer a useful means to quickly assess abnormal motor activity and the effect of drug treatment in PD.

AB0103 SITE SPECIFICITY OF RHEUMATOID ARTHRITIS INFLAMMATION: A SECONDARY ANALYSIS OF BIOPSIES FROM RADIAL AND ULNAR ASPECTS OF MCP JOINTS

Background

Ulnar drift is a common complication of Rheumatoid Arthritis (RA) (1,2). There is no clear consensus regarding the etiology of the hand deformity. Observations from corrective hand surgery and other studies have noted more pronounced inflammation in the radial site of the MCP-joints (3,4). This could partly explain the pathophysiology behind the ulnar deviation.

Objectives

To determine if there is more pronounced inflammation, measured by increased CD-68 expression (5) and Krenn-synovitis score (6), at the radial side of the MCP joints when compared to the ulnar side, in patients with verified RA.

Methods

We included RA patients from a previous study who had biopsies taken from the most affected joints based on clinical examination and ultrasound (7). Twenty-nine PIP-, MCP- and wrist-joints were biopsied. Biopsies from the MCP-joints were taken from the dorso-ulnar and dorso-radial concavity. Inflammation was graded by the Krenn-synovitis score (0-9) and the density of CD-68-positive cells (%). The difference between radial and ulnar joint inflammation was calculated by paired t-test. P-value <0.05 was considered statistically significant.

Results

In 8 patients biopsies were taken from both the ulnar and the radial site of the same MCP-joint. The mean difference in inflammation on the radial and ulnar site of MCP-joints was based on differences in CD-68 density: 0,67% (95%-CI -4,77 to 6,10; P = 0,77) (Figure 1) and Krenn-score: 0,83 (95%-CI -1,31 to 2,98; P = 0,36), respectively.

Figure 1.

Paired data on CD-68 percentage in radial and ulnar sites

Conclusion

There was no difference in concentration of inflammatory cells or overall synovial pathology between the radial and ulnar site of MCP-joints in RA patients. The impression of a more pronounced inflamed synovium on the radial site of MCP joints, as observed during surgery, does not seem to arise from an immunological preference, but rather to be linked to a larger synovial volume.

References

[1]Wise KS: The anatomy of the metacarpo-phalangeal joints, with observations of the aetiology of ulnar drift. J. Bone Joint Surg. Br. 1975; 57:485–90

[2]Johnsson PM, Eberhardt K: Hand deformities are important signs of disease severity in patients with early rheumatoid arthritis. Rheumatology 2009; 48:1398–1401

[3]Philpott H.T. Synovial tissue perivascular edema is associated with altered gait patterns in patients with knee osteoarthritis, Osteoarthritis and Cartilage. 2022; 30(1): 42-51

[4]Tan AL, Tanner SF, Conaghan PG, et al.: Role of metacarpophalangeal joint anatomic factors in the distribution of synovitis and bone erosion in early rheumatoid arthritis. Arthritis Rheum. 2003; 48:1214–22

[5]Zhang X.-P: Addition of Fibroblast-Stromal Cell Markers to Immune Synovium Pathotypes Better Predicts Radiographic Progression at 1 Year in Active Rheumatoid Arthritis, Frontiers in Immunology 2021; 12: 778480

[6]Krenn V, Morawietz L, Burmester G-R, et al.: Synovitis score: discrimination between chronic low-grade and high-grade synovitis. Histopathology 2006; 49:358–364

[7]Andersen M, Ellegaard K, Hebsgaard JB, et al.: Ultrasound colour Doppler is associated with synovial pathology in biopsies from hand joints in rheumatoid arthritis patients: a cross-sectional study. Ann. Rheum. Dis. 2014; 73:678–683

Acknowledgements

The authors would like to thank the study participants as well as Inger Wätjen, Eva Littrup Andersen, Mette Okkels, Jette Møller Frøsig and Suzi Høeg Madsen for technical assistance. I have no acknowledgements to declare.

Disclosure of Interests

Katrine Skovsgaard Itenov: None declared, Niels Søe: None declared, Else Marie Bartels: None declared, Henning Bliddal: None declared, Martin Andersen Grant/research support from: The primary study was supported by unrestricted grants from Novo Nordisk, Employee of: Was employed at Novo Nordisk A/S during the conduction of the study.

The effects of weight loss on imaging outcomes in osteoarthritis of the hip or knee in people who are overweight or obese: a systematic review

OBJECTIVE

To evaluate the structural effects of weight loss on hip or knee osteoarthritis (OA) and to summarize which structural joint pathologies have been examined and the evidence for the outcome measurement instruments applied.

DESIGN

Based on a pre-specified protocol (available: PROSPERO CRD42017065263), we conducted a systematic search of the bibliographic databases, Medline, Embase and Web of Science identifying longitudinal articles reporting the effects of weight loss on structural imaging outcomes in OA of the hip or knee in people who are overweight or obese.

RESULTS

From 1625 potentially eligible records, 14 articles (from 6 cohorts) were included. 2 cohorts were derived from RCTs. Evaluated pathologies were: articular cartilage (n = 7), joint space width (n = 3), bone marrow lesions (n = 5), synovitis (n = 2), effusion (n = 1), meniscus (n = 3), bone marrow density (n = 1) and infrapatellar fat pad (IPFP; n = 2). Cartilage showed conflicting results when evaluating cartilage thickness by direct thickness measurements. Compositional dGEMRIC and T2 mapping measures in early knee OA showed trends towards reduced cartilage degeneration. Joint space width on conventional radiographs showed no change. Weight loss reduced the size of the IPFP. Synovitis and effusion were not affected. Following weight loss DXA showed bone loss at the hip.

CONCLUSION

We did not find consistent evidence of the effects of weight loss on OA structural pathology in people who are overweight or obese. There is a need to achieve consensus on which structural pathologies and measurements to apply in weight loss and OA research.

Relationship between weight loss in obese knee osteoarthritis patients and serum biomarkers of cartilage breakdown: secondary analyses of a randomised trial

OBJECTIVE

To explore effects of weight loss and maintenance on serum cartilage biomarkers denaturation neoepitope for Collagen2 (Coll2-1) and Fibulin3 fragment (Fib3-2), as well as correlations between Coll2-1 and Fib3-2 and symptomatic improvement, in a knee osteoarthritis (KOA) population.

DESIGN

192 obese KOA patients followed a 16 week weight loss intervention and 52 weeks weight maintenance (ClinicalTrials.gov identifier: NCT00655941). Assessments were at 0, 8, 16 and 68 weeks. Serum Coll2-1 and Fib3-2 were determined with ELISA, and symptoms by the Knee Osteoarthritis Outcome Score (KOOS) questionnaire. Changes from week 0 and association between changes from baseline in body weight and Coll2-1, Fib3-2, and the 5 KOOS domains were assessed at all time points.

RESULTS

Coll2-1 changes from baseline showed a decrease at week 8 (P = 0.0002), no change at week 16 (P = 0.49), and an increase at week 68 (P = 0.036). Fib3-2 showed an increase from baseline at week 8 (P = 0.0015) and 16 (P < 0.0001), but none at week 68 (P = 0.23). No statistically significant correlations were found between changes in body weight and Coll2-1 and Fib3-2 at any time point (r < 0.05; P > 0.49). At all time-points there were significant positive correlations between changes from baseline in Coll2-1 and in KOOS_{Sports/Recreation} (week 8, 16, 68: r = 0.17; P = 0.03; r = 0.16; P = 0.04; and r = 0.17; P = 0.04, respectively).

CONCLUSION

The clinical improvement after a substantial weight loss and weight maintenance in KOA patients was not associated with decrease in markers of cartilage breakdown Coll2-1 or Fib3-2, even with indications of a slightly negative effect.

New perspectives on the development of muscle contractures following central motor lesions

Muscle contractures are common in patients with central motor lesions, but the mechanisms responsible for the development of contractures are still unclear. Increased or decreased neural activation, protracted placement of a joint with the muscle in a short position and muscle atrophy have been suggested to be involved, but none of these mechanisms are sufficient to explain the development of muscle contractures alone. Here we propose that changes in tissue homeostasis in the neuromuscular-tendon-connective tissue complex is at the heart of the development of contractures, and that an integrated physiological understanding of the interaction between neural, mechanical and metabolic factors, as well as genetic and epigenetic factors, is necessary in order to unravel the mechanisms that result in muscle contractures. We hope thereby to contribute to a reconsideration of how and why muscle contractures develop in a way which will open a window towards new insight in this area in the future.

Changes in ultrasound assessed markers of inflammation following intra-articular steroid injection combined with exercise in knee osteoarthritis: exploratory outcome from a randomized trial

OBJECTIVE

Knee osteoarthritis (KOA) is a multifactorial joint disease affecting many people worldwide. Recommended treatments for KOA include exercise and steroid injections, or a combination of these. The objective of this exploratory outcome analysis of a randomized trial was to assess changes in inflammation markers assessed by ultrasound imaging (US) in KOA secondary to intra-articular corticosteroid injection given prior to exercise therapy.

DESIGN

This study is a sub-study to a larger clinical trial which compared the clinical effects of steroid injection in KOA to placebo injection, both given prior to exercise therapy. The US outcomes were changes from baseline in US-assessed synovial size, Doppler activity presence in the synovial membrane, and numbers of US-detected Baker's cysts. US was performed at baseline, week 14 (exercise stop), and week 26 (follow-up).

RESULTS

Fifty participants received steroid injection, and 50 received placebo injection. All participants received 12 weeks of exercise. Forty-five and 44, respectively, completed the study. At week 14, the group difference in the change in synovium thickness was 2.2 mm (95%, confidence interval (CI) -0.5 to 4.8), P = 0.11. There were no group differences in the changes in distribution of patients with presence of synovial Doppler activity (P = 0.98) or Baker's cysts (P = 0.35). There were no statistically significant differences between groups at week 26 in any outcome.

CONCLUSION

Intra-articular steroid injection of KOA-patients prior to a 3 months exercise programme did not reduce synovial hypertrophy, synovial Doppler activity, or Baker's cyst presence more than a placebo saline injection according to US-assessments.

TRIAL REGISTRATION

EudraCT: 2012-002607-18.

Correlations between fatigue and disease duration, disease activity, and pain in patients with rheumatoid arthritis: a systematic review

OBJECTIVES

Rheumatoid arthritis (RA) patients suffer from disabling fatigue but the causes of this condition are unknown. Our aim was to assess which of the variables disease activity, disease duration, and pain is associated with fatigue.

METHOD

We conducted a systematic literature search in MEDLINE and EMBASE, followed by selection of studies according to set criteria, data extraction, and statistical analyses of the relationships in RA between fatigue and the following covariates: disease duration, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the 28-joint Disease Activity Score (DAS28), swollen to tender joint count ratio (STR), and pain. Linear regression analyses of fatigue regressed on each of the six covariates, and a multiple regression analysis where fatigue was regressed on the six covariates through a forward selection procedure was carried out with construction of correlation measures between fatigue and the covariates.

RESULTS

A total of 121 studies were included in the analyses, including > 100 000 RA patients. A high level of fatigue was seen even in well-treated patients, demonstrating fatigue as a major problem in RA. Fatigue was found to be positively correlated with pain, CRP, DAS28, and ESR but not with the STR or disease duration, with pain as the overall domineering factor.

CONCLUSIONS

Fatigue has a substantial influence on the lives of RA patients, independent of disease duration. Pain is the domineering factor in the experience and degree of fatigue. Disease activity is positively correlated to fatigue but does not contribute substantially when pain is considered. Optimal pain relief is therefore an important part of the treatment to improve fatigue in RA.

Danish VISA-A questionnaire with validation and reliability testing for Danish-speaking Achilles tendinopathy patients

The VISA-A questionnaire has proven to be a valid and reliable tool for assessing severity of Achilles tendinopathy (AT). The aim was to translate and cross-culturally adapt the VISA-A questionnaire for a Danish-speaking AT population, and subsequently perform validity and reliability tests. Translation and following cross-cultural adaptation was performed as translation, synthesis, reverse translation, expert review, and pretesting. The final Danish version (VISA-A-DK) was tested for reliability on healthy controls (n = 75) and patients (n = 36). Tests for internal consistency, validity, and structure were performed on 71 patients. VISA-A-DK showed good reliability for patients (r = 0.80 ICC = 0.79) and healthy individuals (r = 0.98 ICC = 0.97). Internal consistency was 0.73 (Cronbach's alpha). The mean VISA-A-DK score in AT patients was 51 [47-55]. This was significantly lower than healthy controls with a score of 93 (90-95). Criterion validity was considered good when comparing the scores of the Danish version with the original version in both healthy individuals and patients. VISA-A-DK is a valid and reliable instrument and has shown compatible to the original version in assessment of AT patients. VISA-A-DK is a useful tool in the assessment of AT, both in research and in a clinical setting.

Patient-Reported Outcome (PRO) questionnaires for young to middle-aged adults with hip and groin disability: a systematic review of the clinimetric evidence

BACKGROUND/AIM

To recommend Patient-Reported Outcome (PRO) questionnaires to measure hip and groin disability in young-aged to middle-aged adults.

METHODS

A systematic review was performed in June 2014. The methodological quality of the studies included was determined using the COnsensus-based Standards for the selection of health Measurement INstruments list (COSMIN) together with standardised evaluations of measurement properties of each PRO.

RESULTS

Twenty studies were included. Nine different questionnaires for patients with hip disability, and one for hip and groin disability, were identified. Hip And Groin Outcome Score (HAGOS), Hip Outcome Score (HOS), International Hip Outcome Tool-12 (IHOT-12) and IHOT-33 were the most thoroughly investigated PROs and studies including these PROs reported key aspects of the COSMIN checklist. HAGOS and IHOT-12 were based on studies with the least ratings of poor study methodology (23% and 31%, respectively), whereas IHOT-33 and HOS had a somewhat larger distribution (46%). These PROs all contain adequate measurement qualities for content validity (except HOS), test-retest reliability, construct validity, responsiveness and interpretability. No information or poor quality rating on methodological aspects made it impossible to fully evaluate the remaining PROs at present.

CONCLUSIONS

HAGOS, HOS, IHOT-12 and IHOT-33 can be recommended for assessment of young-aged to middle-aged adults with pain related to the hip joint, undergoing non-surgical treatment or hip arthroscopy. At present, HAGOS is the only PRO also aimed for young-aged to middle-aged adults presenting with groin pain and is recommended for use in this population.

TRIAL REGISTRATION NUMBER

CRD42014009995.

Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials

The aim of this study was to assess the clinical efficacy and safety of oral ginger for symptomatic treatment of osteoarthritis (OA) by carrying out a systematic literature search followed by meta-analyses on selected studies. Inclusion criteria were randomized controlled trials (RCTs) comparing oral ginger treatment with placebo in OA patients aged >18 years. Outcomes were reduction in pain and reduction in disability. Harm was assessed as withdrawals due to adverse events. The efficacy effect size was estimated using Hedges' standardized mean difference (SMD), and safety by risk ratio (RR). Standard random-effects meta-analysis was used, and inconsistency was evaluated by the I-squared index (I(2)). Out of 122 retrieved references, 117 were discarded, leaving five trials (593 patients) for meta-analyses. The majority reported relevant randomization procedures and blinding, but an inadequate intention-to-treat (ITT) analysis. Following ginger intake, a statistically significant pain reduction SMD = -0.30 ([95% CI: [(-0.50, -0.09)], P = 0.005]) with a low degree of inconsistency among trials (I(2) = 27%), and a statistically significant reduction in disability SMD = -0.22 ([95% CI: ([-0.39, -0.04)]; P = 0.01; I(2) = 0%]) were seen, both in favor of ginger. Patients given ginger were more than twice as likely to discontinue treatment compared to placebo ([RR = 2.33; 95% CI: (1.04, 5.22)]; P = 0.04; I(2) = 0%]). Ginger was modestly efficacious and reasonably safe for treatment of OA. We judged the evidence to be of moderate quality, based on the small number of participants and inadequate ITT populations. Prospero: CRD42011001777.

Effect of a 16 weeks weight loss program on osteoarthritis biomarkers in obese patients with knee osteoarthritis: a prospective cohort study

OBJECTIVE

Changes in biomarkers for bone and cartilage in knee osteoarthritis (KOA) may reflect changes in tissue turnover induced by interventions. The aim of this study was to assess the effect on osteoarthritis biomarkers of an intensive weight loss intervention in obese KOA patients.

METHODS

192 obese KOA patients followed a 16 weeks weight loss intervention (ClinicalTrials.gov: NCT00655941). Serum Cartilage Oligomeric Matrix Protein (sCOMP), Urine C-terminal telopeptide of collagen type II (uCTX-II) and type I (uCTX-I) were determined by enzyme-linked immunoassay (ELISA) at baseline and after 16 weeks. Patient-reported symptoms were assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS) Questionnaire without the sports and recreation score (KOOS-4). Change from baseline was analyzed using Analysis of CoVariance (ANCOVA) adjusting for sex, age, and body mass index (BMI). Bivariate associations were analyzed using Spearman's test of rank correlation.

RESULTS

175 patients completed the treatment and lost mean 13.4 (95% CI: 12.5-14.4) kg. sCOMP concentration decreased on average 1.1 (95% CI: -1.5 to -0.8) U/L with a correlation to weight loss (r = -0.17, P = 0.028), but not to change in KOOS-4 (r = -0.13, P = 0.091). uCTX-II increased significantly, mean 69 (95% CI: 31-106) ng/mmol creatinine, with no relation to weight loss (P = 0.14). Change in uCTX-II was reversely related to change in KOOS-4 (r = -0.28, P = 0.0003). uCTX-I increased, mean 67 (95% CI: 47-87) μg/mmol creatinine, and correlated to weight loss (r = 0.22, P = 0.0007), while not to KOOS-4 (P = 0.93).

CONCLUSION

A rapid substantial weight loss in obese KOA patients was weakly, while significantly associated with a reduction in sCOMP, and increases in both uCTX-II and uCTX-I.

Correlations between radiographic assessments and MRI features of knee osteoarthritis--a cross-sectional study

OBJECTIVES

To assess correlations between Kellgren & Lawrence (KL) gradings, minimum joint space width (mJSW) measurements and the Boston Leeds Osteoarthritis Knee Score (BLOKS) within a cohort of obese patients with knee osteoarthritis (KOA).

METHODS

192 Participants were recruited from an outpatient clinic (ClinicalTrials.gov: NCT00655941). Inclusion criteria were age ≥50 years, body mass index (BMI) ≥30 kg/m(2) plus symptomatic and verified KOA. 1.5 T magnetic resonance imaging (MRI) scans were assessed using BLOKS and bi-plane radiography by mJSW and KL. Statistics used were Spearman rank correlation coefficients.

RESULTS

The average patient was 63 years of age, female and had a BMI of 37. KL gradings correlated to cartilage damage, bone marrow lesions and meniscus pathology (r = 0.15-0.76) and similar results were found for the relationship between BLOKS and mJSW. BLOKS assessed knee joint pathology co-segregated with compartment and grade specific KL (P < 0.0001). BLOKS variables were statistically significant correlated, particularly in the medial tibiofemoral compartment (r = 0.42-0.80). Adjusting for age, gender and BMI did not alter these associations.

CONCLUSION

Extensive pathological damage is present even in mild radiographic KOA and BLOKS gradings and KL scores increase together. Analyses of compartment specific KL scores revealed differences in their relationship to the assessed MRI variables. Our study displays the segregation of MRI gradings with respect to location and level of radiographic scores, reveals a high inter-dependency of MRI-assessed structures, and describes some redundancy of specific BLOKS variables.

Weight loss is effective for symptomatic relief in obese subjects with knee osteoarthritis independently of joint damage severity assessed by high-field MRI and radiography

OBJECTIVE

With an increasing prevalence of older and obese citizens, the problems of knee osteoarthritis (KOA) will escalate. Weight loss is recommended for obese KOA patients and in a majority of cases this leads to symptomatic relief. We hypothesized that pre-treatment structural status of the knee joint, assessed by radiographs, 1.5 T magnetic resonance imaging (MRI) and knee-joint alignment, may influence the symptomatic changes following a significant weight reduction.

DESIGN

Patients were recruited from a Department of Rheumatology. Eligibility criteria were age above 50 years, body mass index ≥ 30 kg/m(2), primary KOA diagnosed according to the American College of Rheumatology (ACR) criteria and having verified structural damage. Patients underwent a 16 weeks dietary programme with formula products and counselling. MRI and radiographs of the most symptomatic knee were obtained at baseline and assessed for structural damage using the Boston-Leeds Osteoarthritis of the Knee Score, minimum joint space width and Kellgren-Lawrence score. Imaging variables, muscle strength and degree of alignment, were examined as predictors of changes in Knee Osteoarthritis Outcome Score (KOOS) and Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) - Osteoarthritis Research Society International (OARSI) Responder Criterion.

RESULTS

Structural damage at baseline assessed by imaging, muscle strength or knee-joint alignment showed no statistically significant association to changes in KOOS pain and function in daily living (r ≤ 0.13; P>0.05) or the OMERACT-OARSI Responder Criterion (OR 0.48-1.68; P-values ≥ 0.13).

CONCLUSIONS

Presence of joint damage did not preclude symptomatic relief following a clinically relevant weight loss in older obese patients with KOA. Neither muscle strength nor knee-joint alignment was associated with the degree of symptomatic relief.

Calcium-dependence of Donnan potentials in glycerinated rabbit psoas muscle in rigor, at and beyond filament overlap; a role for titin in the contractile process

In glycerinated rabbit psoas muscle, Donnan potential measurements demonstrated that the net electric charge on the actin-myosin matrix undergoes a sharp switch-like transition at pCa(50) = 6.8. The potentials are 2 mV less negative at the lower pCa(2+) (P < 0.001). If ATP is present, the muscle contracts and breaks the microelectrode. Therefore the rigor state was studied. There is no reason to suppose a priori that a similar voltage switch does not occur during contraction, however. Calcium dependence is still apparent in muscles stretched beyond overlap (sarcomere length>3.8 μm) and is also seen in the gap filaments between the A- and I-band ends; further stretching abolishes the dependence. These experiments strongly suggest that calcium dependence is controlled initially by the titin component, and that this control is lost when titin filaments break. We suppose that that effect is mediated by the titin kinase in the M-line region and may involve the extensible PEVK region of titin. There is great interest in the electric charge on proteins in muscle within the structural system. We suggest how changes in these charges may control the calcium activation process. We also suggest some simple experimental approaches that could clarify these effects.

Articular cartilage thickness measured with US is not as easy as it appears: a systematic review of measurement techniques and image interpretation

BACKGROUND

Theoretically, the high spatial resolution of US makes it well suited to monitor the decrease in articular cartilage thickness in osteoarthritis. A requirement is, however, that the borders of the cartilage are correctly identified and that the cartilage is measured under orthogonal insonation. If US measurements are compared to measurements with other techniques, they should be corrected for the higher sound speed in cartilage.

PURPOSE

To study whether investigators correctly identify the articular cartilage, whether they insonate orthogonally, and whether they correct for sound speed.

MATERIALS AND METHODS

A literature search limited to the last 10 years of studies applying US to measure cartilage thickness.

RESULTS

15 studies were identified and they referred to another 8 studies describing methods of thickness measurement. 11 of the 15 studies identified the superficial cartilage border incorrectly, and 6 applied oblique insonation. 2 of the 15 studies corrected for sound speed. Of the further 8 studies, one might correctly identify the superficial cartilage border, 4 applied oblique insonation, and none corrected for sound speed.

CONCLUSION

We found that the majority of studies over the last 10 years, evaluating articular cartilage thickness with US, underestimated the cartilage thickness by not including the leading interface as part of the cartilage. Since the cartilage is relatively thin, this error is substantial. Some investigators also overestimated cartilage thickness by using oblique insonation of the cartilage. By not correcting for the high sound speed in cartilage, most investigators underestimated the cartilage thickness.

The number needed to treat for second-generation biologics when treating established rheumatoid arthritis: a systematic quantitative review of randomized controlled trials

OBJECTIVE

To evaluate the number needed to treat (NNT) and the number needed to harm (NNH) of the second-generation biologics abatacept, certolizumab, golimumab, rituximab, and tocilizumab in patients with established rheumatoid arthritis (RA) taking concomitant methotrexate (MTX).

METHODS

A systematic literature search of MEDLINE, EMBASE, Web of Science, and the Cochrane Register of Controlled Trials was conducted up to 1 November 2009. We selected any published randomized, double-blind, MTX-controlled study including RA patients with a mean disease duration of at least 5 years before entering a pivotal trial on second-generation biological therapy. Studies eligible for inclusion involved patients, who had previously shown inadequate response to conventional disease-modifying anti-rheumatic drug (DMARD) therapy. Pre-specified binary outcomes were extracted with a preference for 1-year data (6-month data were used if no data were available for 1 year). Two reviewers independently extracted the data necessary to estimate the absolute measures in a non-responder intention-to-treat (ITT) analysis.

RESULTS

Five randomized controlled trials, one for each of the drugs, were selected and data extracted according to published data at endpoint for American College of Rheumatology 50% (ACR50)-responding patients, and withdrawals due to adverse events. NNT ranged from four to six treated patients to achieve one ACR50 response, while withdrawals due to adverse events were few and non-significant compared to the placebo group, except for rituximab administered as 1000 mg.

CONCLUSION

Comparable efficacy was shown by the five biological agents studied, with few adverse events. However, for rituximab, tocilizumab, and golimumab, only 6-month data were available, hampering the external validity with regard to long-term efficacy and tolerability. A low dose (500 mg) of rituximab may be as effective as the recommended dose of 1000 mg.

Isokinetic and isometric muscle strength in a healthy population with special reference to age and gender

AIM

Muscle strength is an excellent indicator of general health when based on reliable measurements. Muscle strength data for a healthy population are rare or non-existent. The aim of the present study was to measure a set of normal values for isometric and isokinetic muscle strength for all the major joint movements of the body and, from these data, to create a basis for comparison of the muscle strength of an individual with the expected value in a normal population.

METHODS

A randomly selected group, aged 20-80 years, from the Copenhagen City Heart Study were studied. The group was subgrouped according to age and gender. Isometric and isokinetic muscle strength was measured in each subject across the main joints in the body. A statistical model was developed that encompassed the three main muscle groups: upper limbs, trunk and lower limbs.

RESULTS

Muscle strength in healthy men decreases in a linear fashion from the age of 25 years down to between 54% and 89% at the age of 75 years, and seems not highly dependent on any other parameter than age. For women, the muscle strength is dependent on weight and is only related to age from around 40 years of age. The decrease in muscle strength from the age around 40 to 75 years is 48-92%. For most muscle groups, men are 1.5-2 times stronger than women, with the oldest men having strength similar to that observed among the youngest women.

CONCLUSION

We developed a model to compare the isometric and isokinetic muscle strength of all the major joint movements of an individual with values for a healthy man or woman at any age in the range of 20-80 years. In all age groups, women have lower muscle strength than men. Men's muscle strength declines with age, while women's muscle strength declines from the age of 41 years.

Validity, reliability and responsiveness of patient-reported outcome questionnaires when assessing hip and groin disability: a systematic review

BACKGROUND

Novel treatment interventions are advancing rapidly in the management of hip and groin disability in the physically active young to middle-aged population.

OBJECTIVE

To recommend the most suitable patient-reported outcome (PRO) questionnaires for the assessment of hip and groin disability based on a systematic review of evidence of validity, reliability and responsiveness of these instruments.

METHODS

MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, PsycINFO, SportsDiscus and Web of Science were all searched up to January 2009. Two reviewers independently rated measurement properties of the PRO questionnaires in the included studies, according to a standardised criteria list.

RESULTS

The computerised search identified 2737 publications. Forty-one publications investigating measurement properties of PRO questionnaires assessing hip or groin disability were included in the study. Twelve different questionnaires designed for patients with hip disability and one questionnaire for patients with groin disability were identified. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) contains adequate measurement qualities to evaluate patients with hip osteoarthritis (OA) or total hip replacement (THR). Hip Outcome Score (HOS) is the best available questionnaire for evaluating hip arthroscopy, but the Inguinal Pain Questionnaire, the only identified questionnaire evaluating groin disability, does not contain adequate measurement qualities.

CONCLUSIONS

HOOS is recommended for evaluating patients with hip OA undergoing non-surgical treatment and surgical interventions such as THR. HOS is recommended for evaluating patients undergoing hip arthroscopy. Current and new PRO questionnaires should also be evaluated in younger patients (age <50) with hip and/or groin disability, including surgical and non-surgical patients.

Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials

Observational studies have found that dietary calcium intake is inversely related to body weight and body fat mass. One explanatory mechanism is that dietary calcium increases faecal fat excretion. To examine the effect of calcium from dietary supplements or dairy products on quantitative faecal fat excretion, we performed a systematic review with meta-analysis. We included randomized, controlled trials of calcium (supplements or dairy) in healthy subjects, where faecal fat excretion was measured. Meta-analyses used random-effects models with changes in faecal fat excreted expressed as standardized mean differences, as the studies assessed the same outcome but measured in different ways. An increased calcium intake resulted in increased excretion of faecal fat by a standardized mean difference of 0.99 (95% confidence intervals: 0.63-1.34; P < 0.0001; expected to correspond to approximately 2g day(-1)) with moderate heterogeneity (I(2) = 49.5%) indicating some inconsistency in trial outcomes. However, the dairy trials showed homogeneous outcomes (I(2)=0%) indicating consistency among these trials. We estimated that increasing the dairy calcium intake by 1241 mg day(-1) resulted in an increase in faecal fat of 5.2 (1.6-8.8) g day(-1). In conclusion, dietary calcium has the potential to increase faecal fat excretion to an extent that could be relevant for prevention of weight (re-)gain. Long-term studies are required to establish its potential contribution.

Does the hip powder of Rosa canina (rosehip) reduce pain in osteoarthritis patients?--a meta-analysis of randomized controlled trials

OBJECTIVE

Meta-analysis of randomized controlled trials (RCTs)--of a hip powder of Rosa canina (rosehip) preparation for symptomatic treatment of osteoarthritis (OA), in order to estimate the empirical efficacy as a pain reducing compound.

METHOD

RCTs from systematic searches were included if they explicitly stated that OA patients were randomized to either rosehip or placebo. The primary outcome was reduction in pain calculated as effect size (ES), defined as the standardized mean difference (SMD). As secondary analysis the number of responders to therapy was analyzed as Odds Ratios (OR), and expressed as the Number Needed to Treat (NNT). Restricted Maximum Likelihood (REML) methods were applied for the meta-analyses using mixed effects models.

RESULTS

The three studies (287 patients and a median trial-duration of 3 months)--all supported by the manufacturer (Hyben-Vital International)--showed a reduction in pain scores by rosehip powder (145 patients) compared to placebo (142 patients): ES of 0.37 [95% confidence interval (CI): 0.13-0.60], P=0.002. Test for homogeneity seemed to support that the efficacy was consistent across trials (I(2)=0%). Thus it seems reasonable to assume that the three studies were measuring the same overall effect. It seemed twice as likely that a patient allocated to rosehip powder would respond to therapy, compared to placebo (OR=2.19; P=0.0009); corresponding to a NNT of six (95% CI: 4-13) patients.

CONCLUSIONS

Although based on a sparse amount of data, the results of the present meta-analysis indicate that rosehip powder does reduce pain; accordingly it may be of interest as a nutraceutical, although its efficacy and safety need evaluation and independent replication in a future large-scale/long-term trial.

Symptomatic efficacy of avocado-soybean unsaponifiables (ASU) in osteoarthritis (OA) patients: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy of preparations with avocado-soybean unsaponifiables (ASUs) in osteoarthritis (OA) patients using meta-analysis on randomized controlled trials (RCTs).

METHOD

RCTs from systematic searches were included if they explicitly stated that hip and/or knee OA patients were randomized to either ASU or placebo. The co-primary outcome was reduction in pain and Lequesne index, leading to effect size (ES), calculated as the standardized mean difference. As secondary analysis, the number of responders to therapy was analyzed as odds ratios (ORs). Restricted maximum likelihood methods were applied for the meta-analyses, using mixed effects models.

RESULTS

Four trials--all supported by the manufacturer--were included, with 664 OA patients with either hip (41.4%) or knee (58.6%) OA allocated to either 300 mg ASU (336) or placebo (328). Average trial duration was 6 months (range: 3-12 months). Though based on heterogeneous results, the combined pain reduction favored ASU (I(2) = 83.5%, ES = 0.39 [95% confidence intervals: 0.01-0.76], P=0.04). Applying the Lequesne index also favored ASU (I(2) = 61.0%, ES = 0.45 [0.21-0.70], P = 0.0003). Secondarily, the number of responders following ASU compared to placebo (OR = 2.19, P = 0.007) corresponded to a number needed to treat of six (4-21) patients.

CONCLUSIONS

Based on the available evidence, patients may be recommended to give ASU a chance for e.g., 3 months. Meta-analysis data support better chances of success in patients with knee OA than in those with hip OA.

Aquatic exercise for the treatment of knee and hip osteoarthritis

BACKGROUND

Clinical experience indicates that aquatic exercise may have advantages for osteoarthritis patients.

OBJECTIVES

To compare the effectiveness and safety of aquatic-exercise interventions in the treatment of knee and hip osteoarthritis.

SEARCH STRATEGY

We searched MEDLINE from 1949, EMBASE from 1980, CENTRAL (Issue 2, 2006), CINAHL from 1982, Web of Science from 1945, all up to May 2006. There was no language restriction.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised clinical trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed the internal validity of included trials and extracted data. Pooled results were analyzed using standardized mean differences (SMD).

MAIN RESULTS

There is a lack of high-quality studies in this area. In total, six trials (800 participants) were included. At the end of treatment for combined knee and hip osteoarthritis, there was a small-to-moderate effect on function (SMD 0.26, 95% confidence interval (CI) 0.11 to 0.42) and a small-to-moderate effect on quality of life (SMD 0.32, 95% CI 0.03 to 0.61). A minor effect of a 3% absolute reduction (0.6 fewer points on a 0 to 20 scale) and 6.6% relative reduction from baseline was found for pain. There was no evidence of effect on walking ability or stiffness immediately after end of treatment. No evidence of effect on pain, function or quality of life were observed on the one trial including participants with hip osteoarthritis alone. Only one trial was identified including knee osteoarthritis alone, comparing aquatic exercise with land-based exercise. Immediately after treatment, there was a large effect on pain (SMD 0.86, 95%CI 0.25 to 1.47; 22% relative percent improvement), but no evidence of effect on stiffness or walking ability. Only two studies reported adverse effects, that is, the interventions did not increase self-reported pain or symptom scores. No radiographic evaluation was performed in any of the included studies.

AUTHORS' CONCLUSIONS

Aquatic exercise appears to have some beneficial short-term effects for patients with hip and/or knee OA while no long-term effects have been documented. Based on this, one may consider using aquatic exercise as the first part of a longer exercise programme for osteoarthritis patients. The controlled and randomised studies in this area are still too few to give further recommendations on how to apply the therapy, and studies of clearly defined patient groups with long-term outcomes are needed to decide on the further use of this therapy in the treatment of osteoarthritis.

The Uremic Environment and Muscle Dysfunction in Man and Rat

BACKGROUND

Patients reaching end-stage renal disease experience debilitating fatigue, with progression of this disease, rendering patients dysfunctional in their everyday lives.

METHODS

In vivo measurements of muscle function, assessed using surface electromyography (EMG), were made on 25 patients prior to and after a session of hemodialysis (HD) treatment, along side in vitro measurements of muscle function in isolated rat muscles incubated in normal or uremic conditions approximating to those found in uremic rats (rat uremic: RU) or uremic humans (human uremic: HU).

RESULTS

HD significantly affected plasma values, e.g. reducing urea (69%), creatinine (62%), potassium (23%) and phosphate (48%) concentrations in patients (all p < 0.01). Treatment also improved the EMG frequency of 2nd dorsal interosseous (fast-twitch) (p < 0.01), although no change was noted for vastus lateralis (slow-twitch). In isolated rat muscles, a uremic environment had no significant effect on slow-twitch soleus during field stimulation, however, in fast-twitch extensor digitorum longus, a significant 23% (RU) and 22% (HU) faster rate of decline in force was measured, compared to controls (p < 0.001 and p < 0.01, respectively).

CONCLUSION

It is concluded that (1) muscle weakness and its electrophysiological correlates may be rapidly induced by uremic solutes and rapidly reversed when the solutes are removed by dialysis, and (2) fast-twitch muscles are more readily affected by uremic conditions than slow-twitch muscles.

Learning effect of isokinetic measurements in healthy subjects, and reliability and comparability of Biodex and Lido dynamometers

The aim of this study was to examine the learning effect during a set of isokinetic measurements, to evaluate the reliability of the Biodex System 3 PRO dynamometer, and to compare the Biodex System 3 PRO and the Lido Active dynamometers on both extension and flexion over the elbow and the knee at 60 degrees s(-1). Thirteen (nine women, four men) healthy participants were measured five times using the Biodex and once using the Lido dynamometer. The intervals between the first four tests were 20 min, and 1 week between tests 4 and 5. Between Biodex and Lido measurements there was a 20 min time interval. When comparing the first five measurements (Biodex), no systematic effect over time and an excellent reliability were found with respect to elbow and knee flexion and extension. No difference in muscle strength (Nm) between the Biodex and Lido was observed for knee flexion (P = 0.59), knee extension (P = 0.18) and elbow extension (P = 0.63). However, elbow flexion showed a 14.8% (95% CI: 11.2-18.4%; P = 0.0001) higher peak torque on Biodex. In conclusion, no learning effect was observed and the Biodex proved to be a highly reliable isokinetic dynamometer. A difference was observed when comparing Biodex and Lido on elbow flexion, but the difference did not outrange the expected variation found with a typical isokinetic measurement, which is why both sets of equipment seem applicable in clinical practice.

Collagen structure in skin from fibromyalgia patients

The distribution and amount of collagen in skin from a non-tender-point area from fibromyalgia patients was assessed by quantitative analysis of amino acids and by electron and light microscopy. Skin biopsies were obtained from the front of the thigh of 27 females who fulfilled the American College of Rheumatology criteria of fibromyalgia and from eight control subjects who were matched for gender, age and physical activity. Amino acids were determined by high-performance liquid chromatography. Electron and light microscopic investigations were carried out to examine tissue structure. Among the collagen-related amino acids, the mean number of hydroxyproline residues per 1,000 residues was 52.5 and 63.4 in fibromyalgia patients and control subjects, respectively (p = 0.050); proline residues were 81.7 and 110.0 (p = 0.006); and hydroxylysine residues were 14.7 and 10.1 (p = 0.002). The total amount of skin protein in proportion to dry tissue weight was 83.4% and 72.6% in fibromyalgia and controls, respectively (p = 0.037). The overall microscopic picture was normal. The lamellar structure of the perineurium and a deficiency in collagen packing in the endoneurium was observed more frequently and to a larger extent in fibromyalgia patients than in controls. In conclusion, there are some differences between the amino acid composition of skin proteins in fibromyalgia patients compared with controls. The amount of collagen may be lower in skin from fibromyalgia patients, and collagen packing in the endoneurium may be less dense.

Effects of antisecretory factor-derived peptides on contractions in guinea pig colon

Two antisecretory factor (AF)-derived peptides have been studied in relation to effects on motility of guinea pig colon. Colon segments were isolated from adult guinea pigs and incubated in Tyrode Ringer. Motility was measured as the force and frequency of contractions upon addition of the derived peptides AF 1 (8 amino acids (aa)) and AF 3 (10 amino acids). At the lowest concentration (5 pM), peptide AF 1 induced a negative effect on the force of contraction in colon segments; an effect that was abolished by the cholinergic agonist carbachol. Peptide AF 3 induced a significant increase in the force of colon contractions at all concentrations (5-180 pM), with carbachol only reducing the effect of peptide AF 3 at a concentration of 15 pM. Both peptides increased contractile frequency, although the overall response was lower for peptide AF 3 than for peptide AF 1. It is concluded that antisecretory factor-derived peptides may play a role in regulating colon motility such that under pathophysiological conditions, they may serve to hasten the evacuation of noxious agents from the large intestine.

Collagen and muscle pathology in fibromyalgia patients

OBJECTIVE

To measure collagen concentration and search for muscle pathology in muscle non-tender-point areas from fibromyalgia (FM) patients.

METHODS

Muscle biopsies were obtained from m. vastus lateralis of 27 carefully selected, female fibromyalgia patients, and from eight age-matched female control subjects. Amino acids were determined by HPLC and electron microscopy was performed.

RESULTS

The FM patients had lower hydroxyproline and lower total concentration of the major amino acids of collagen than the controls. No significant difference was seen in the concentration of the major amino acids of myosin or of total protein. Electron microscopy showed no significant differences between FM patients and controls although atrophied muscle fibrils occurred in FM patients only, but frequencies were not significantly different.

CONCLUSION

Fibromyalgia patients had a significantly lower amount of intramuscular collagen. This may lower the threshold for muscle micro-injury and thereby result in non-specific signs of muscle pathology.

Use of isokinetic muscle strength as a measure of severity of rheumatoid arthritis: a comparison of this assessment method for RA with other assessment methods for the disease

The aim of this study was to study the association between isokinetic muscle strength (IMS) and other clinical indicators of disability and disease activity in patients with rheumatoid arthritis (RA). A cohort of 36 RA patients was followed over a 1-year period with five measurements of disease activity at regular intervals during this time. IMS was measured at seven angular velocities in both knees, on five separate occasions. The measurement was expressed by the level of the fitted line of the seven peak torque values--IMS30. The association between IMS30 and clinical indicators was stated. As an indicator of disability the score from the Stanford Health Assessment Questionnaire (HAQ) was used. As indicators of disease activity morning stiffness, an index of swelling and pain in the joint, erythrocyte sedimentation rate (ESR) and haemoglobin (Hb) were chosen. Larsen's X-ray score was used as an indicator of bone destruction due to longer-lasting disease activity. IMS was significantly associated with the HAQ score, but not with indicators of disease activity or radiological findings. IMS was significantly associated with changes in indicators of disease activity, but not with the changes in the HAQ score, or in the X-ray-score. IMS showed the strongest association with changes in the degree of arthritis of the knee. In conclusion, IMS was associated with the HAQ score and can therefore be used when measuring outcome in a specific group of RA patients. Changes in IMS were associated with indicators of changes in disease activity, and are therefore usable as a measure of patient outcome. Of particular importance is that IMS decreased if a patient developed active arthritis in the knee, and normalised again when the inflammation decreased.

A method to reduce the number of measured parameters when using isokinetic muscle strength as a clinical indicator in rheumatoid arthritis patients

The aim of the study was to present a method enabling a reduction of the number of measurements when quantifying isokinetic muscle strength (IMS), and to describe an expression for IMS which is independent of measuring conditions. IMS is a measure of muscle strength used to categorise patients and to assess changes over time. IMS measurements involve one or several measures of peak torque at different chosen angular velocities. Comparisons between studies are difficult and an expression of IMS independent of measuring conditions is needed. Thirty-six women with rheumatoid arthritis were followed for 1 year. IMS was measured on five occasions on both knees at seven angular velocities, giving 10 sets of peak-torque data for each patient. The log[peak-torque]-angular-velocity diagram showed a linear relationship. From this, the peak-torque value at the chosen angular velocity of 30 degrees/s (IMS30) was estimated for each test and the uncertainties involved were quantified. IMS30 is a reliable parameter when comparing effort between knees, visits and patients, and may be based on three sets of data only. IMS may be expressed by a single value, IMS30, representing the fitted line in a log[peak-torque]-angular-velocity diagram. The regression line may be fitted by three or more angular velocities. In principle, IMS30 is independent of the chosen angular velocity, which makes it possible to use an estimated value as IMS30 to compare results, studies and centres in between.

[Evidence-based grounds of physical therapy. Focus on training/exercise therapy of musculoskeletal problems]

Evidence of the benefit of exercise for patients with musculoskeletal problems was examined by analysing meta-analyses and systematic reviews. The literature search was confined to studies where pain and/or function was used as the outcome measure. Twenty-three meta-analyses/systematic reviews were covered, and the methodical quality was assessed. Nine out of twelve meta-analyses showed that exercise had a positive effect on groups groups diagnosed with intermittent claudication, fibromyalgia, incontinence, low back pain, and stroke, whereas one meta-analysis (exercise to prevent falls in the elderly) showed no effect. Of the systematic reviews, six out of 12 showed a positive effect and five were inconclusive, owing to the lack of clinical trials. We conclude that much more research in the field of exercise and physiotherapy is needed.

[Pool exercise therapy of rheumatoid arthritis]

Aquatic therapy is a subgroup of balneotherapy and consists of exercises in a hot water pool. It uses the physical properties of water to achieve better mobility for patients whose pain, lack of muscle strength, and joint deformities are inhibiting factors when exercising on land. Pool therapy shows positive effects as part of the treatment of rheumatoid arthritis patients, but too few studies with an acceptable design and a well-defined patient group have been carried out. The documentation available on aquatic therapy indicates that more large clinical, controlled, and randomised studies must be conducted.

MRI of the plantar structures of the foot after falanga torture

Falanga is an ancient form of punishment or torture but is still commonly reported by our refugees. The late result of caning the heel and ball of the foot is a chronic painful condition with few clinical signs. The aim of the present study was to assess, by MRI, possible morphologic characteristics of the heel and ball of the foot, related to falanga and pain in correlation to clinical findings. Magnetic resonance imaging of the foot was obtained in 12 victims exposed to falanga torture and 9 healthy volunteers. Sagittal T1-weighted spin-echo images (TR 616-840 ms, TE 20 ms), T2-weighted spin-echo images (TR 1900 ms, TE 90 ms), and short tau inversion recovery (STIR) images (TR 1200 ms, TE 15 ms, TI 100 ms) were performed. The central portion of the plantar aponeurosis was generally significantly thicker in victims exposed to falanga torture as compared with that of controls (P < 0.05). In all except one of the victims, MRI demonstrated two layers of the thickened plantar aponeurosis: a deeper portion with normal homogeneous low signal intensity (SI) appearance, and a superficial layer with characteristic areas of mixed SI on both T1- and T2-weighted images. There were no signs of chronic muscular compartment syndromes, and the thickness of the plantar pad did not differ between the two groups. Magnetic resonance imaging may demonstrate morphologic characteristics of the plantar aponeurosis which may confirm falanga torture. Further imaging with more specific sequences is warranted to demonstrate the supposed injuries in the compartmental fat tissue chambers and the vascularity of the ball pad of the foot.

Oxygen and lactate concentrations measured in vivo in the intervertebral discs of patients with scoliosis and back pain

STUDY DESIGN

Oxygen concentrations in intervertebral discs were measured in 10 patients during discography and in 13 patients with scoliosis and 11 patients with back pain during spinal surgery. Lactate concentration profiles were measured in 12 of these discs. The discs were graded for degeneration by magnetic resonance imaging and histology where possible.

OBJECTIVES

To determine if oxygen and lactate levels in human discs vary with degree of degeneration. Failure of nutrient transport is thought to lead to disc degeneration.

SUMMARY OF BACKGROUND DATA

The disc is avascular. Oxygen is used by the disc cells, and lactate is produced. Low oxygen and high lactate concentrations have been measured in the center of healthy animal discs.

METHODS

Oxygen concentrations were measured amprometrically. The sterilized gold-needle electrode was introduced into the disc during discography or after the disc was exposed surgically via an anterior approach. Concentration profiles of each disc took approximately 5 minutes to measure. Lactate concentrations were measured biochemically on the excised disc segment.

RESULTS

Oxygen concentrations were highest at the disc surface and fell toward the center. Lactate concentrations showed the reverse profile. Oxygen levels were very variable, ranging from 5-150 mm Hg in the center of the nucleus. No correlation was seen with age, pathology, or degree of degeneration. Lactate concentrations ranged for the most part from 2 mmol/L to 6 mmol/L.

CONCLUSIONS

Concentrations of metabolites depend on cellular activity and on transport of the metabolite between the blood supply and the cell. The correlation between degeneration and nutrition cannot be determined only from metabolite concentrations; measurements of metabolic activity and nutrient transport rates also are required.

The myosin molecule--charge response to nucleotide binding

A decrease in the net fixed electric charge in the A-bands of cross-striated muscle was observed by Bartels and Elliott [2,10] when the muscle went from the rigor to the relaxed condition. The current work localises the source of the charge decrease by following the net charge on myosin (in the form of concentrated gels) and also myosin rod and light meromyosin gels when the gels are exposed to different concentrations of ATP. The work includes a study of muscle A-bands when the muscle is exposed to the same variations in ATP concentrations as the protein gels. The work shows that (i) Only 100-200 microns ATP is needed to initiate the charge decrease between the rigor and relaxed conditions; (ii) the effect of ATP is seen in the muscle A-band and the myosin and myosin rod gels, but not in LMM gels; (iii) pyrophosphate (PPi) shows a similar charge effect to ATP. ADP does not affect the charge on myosin gels, on the other hand. The results suggest that the charge decrease caused by ATP or PPi is due to ligand interaction with one or more sites on the myosin molecule. This interaction causes a disseminated effect in the protein, and a consequent loss in net negative charge either by a decrease in the absorption, of anions to Saroff sites on the protein, or, less probably, by an increase in the absorption of cations at those sites.

Single cell morphology of muscle in patients with chronic muscle pain

In 119 patients referred with suspected fibromyalgia, biopsies from the quadriceps muscle were analyzed for "rubber band" morphology, and isokinetic quadriceps strength was measured. Eighty-four fulfilled the criteria for fibromyalgia, 26 had chronic myofascial pain (CMP) and 9 had other diseases including 5 with concomitant fibromyalgia. Twenty-four CMP patients and 48 fibromyalgia patients were randomly selected to match with regard to sex, age, smoking and drinking habits. "Rubber band" morphology was blindly graded on a biopsy score scale from 0 to 2. A statistically significant difference in biopsy score was found between the two matched groups (P = 0.003); median biopsy score in fibromyalgia was 0.42 and 0.25 in CMP. A cut-off value at 0.33 gave a specificity of 71% and a sensitivity of 63%. Isokinetic muscle strength did not differ in the fibromyalgia and CMP groups and was not related to the biopsy score. "Rubber band" morphology is seen more often in fibromyalgia patients than in CMP patients. The exact genesis of this phenomenon is still unknown but theories connected with the possible pathogenesis of the syndrome are presented.

Patients with polymyositis show changes in muscle protein charges

Polymyositis (PM) appears with indolent proximal muscle weakness and is an inflammatory disease with breakdown of muscle cells. In our study the protein charge concentrations of the contractile proteins in the A and I bands were determined, applying a microelectrode technique. Patients with PM show a lower protein charge concentration than healthy control subjects which may be caused by the breakdown and removal of the proteins in the contractile filaments. A tool to judge the state of the disease as well as an aid in diagnosis may have been found in this method.

A structural study of gels, in the form of threads, of myosin and myosin rod

Images

Diffuse X-ray scatter from myosin heads in oriented synthetic filaments

X-ray results are presented concerning the structural state of myosin heads of synthetic filaments in threads. These were made from purified rabbit skeletal muscle myosin and studied by x-ray diffraction and electron microscopy by Cooke et al. (Cooke, P. H., E. M. Bartels, G. F. Elliott, and R. A. Hughes, 1987, Biophys. J., 51:947-957). X-ray patterns show a meridional peak at a spacing of 14.4 nm. We concentrate here on the only other feature of the axial pattern: this is a central region of diffuse scatter, which we find to be similar to that obtained from myosin heads in solution (Mendelson, R. A., K. M. Kretzschmar, 1980, Biochemistry, 19:4103-4108). This means that the myosin heads have very large random displacements in all directions from their average positions, and that they are practically randomly oriented. The myosin heads do not contribute to the 14.4-nm peak, which must come entirely from the backbone. Comparison with x-ray data from the unstriated Taenia coli muscle of the guinea pig indicates that in this muscle at least 75% of the diffuse scatter comes from disordered myosin heads. The results confirm that the diffuse scatter in x-ray patterns from specimens that contain myosin filaments can yield information about the structural behavior of the myosin heads.

Histological abnormalities in muscle from patients with certain types of fibrositis

In muscle biopsy specimens from fibrositis patients and healthy subjects no differences in electrical charges on the contractile proteins were detected with a microelectrode technique. However, microscopical examination of fibrositis muscle showed muscle fibres connected by a network of reticular or elastic fibres which are absent in normal muscle and which may be the cause of the disorder.

Donnan potentials in rabbit psoas muscle in rigor

Collins and Edwards (1971, Am. J. Physiol., 221:1130-1133) have shown that a tissue potential can be measured with microelectrodes in glycerinated muscle and that this potential is consistent with a Donnan equilibrium of small ions due to the concentration of net fixed electric charge on the contractile proteins. This approach has been combined with x-ray and light diffraction measurements of the muscle lattice dimensions, and the data are used to determine the thick filament charge and thin filament charge under a variety of different conditions. The thick filament charge is a function of the bathing solution, in particular its pH and ionic composition. These parameters are important in determining the volume of the equilibrium lattice and possibly are involved in the contraction mechanism itself.

Donnan potentials from the A- and I-bands of glycerinated and chemically skinned muscles, relaxed and in rigor

Using a combination of microelectrode measurements and high-power microscopy we have demonstrated that different Donnan potentials can be recorded from the A- and I-bands of glycerinated and chemically skinned muscles in rigor, so that the A-band fixed charge concentration exceeds the I-band fixed charge concentration in the rigor condition. In relaxation the two potentials, and therefore the two charge concentrations, are equal in the two bands. X-ray data are presented for relaxed and rigor rat semitendinosus muscle, chemically skinned, and actin and myosin filament charges are calculated under a variety of conditions. Our conclusions are that (a) the fixed (protein) charge is different in the A- and I-bands of striated muscle in the rigor state; (b) the fixed charges are equal in the A- and I-bands of relaxed muscle; (c) the largest charge change between relaxation and rigor is on the thick filament. This occurs whether or not the myosin heads are cross-linked to the thin filaments. (d) Possibly an event on the myosin molecule, the binding of ATP (or certain other ligands) causes a disseminated change that modifies the ion-binding capacity of the myosin rods, or part of them.

Latency relaxation in frog skeletal muscle under hypertonic conditions

The effect of exposure to hypertonic conditions on latency relaxation (LR), twitch tension and resting tension in frog toe muscle was studied. Measurements were carried out in standard and hypertonic conditions (1 to 3.6 times standard tonicity) and following transversal stimulation. In hypertonic conditions, the LR showed increased duration and decreased amplitude. Both time course and amplitude showed the same dependency on sarcomere length as in standard conditions. The fall in amplitude and extension of the time course was proportional to the increase in tonicity up to 2.2 times the tonicity of the standard. At higher tonicities the time course extended earlier and diverged from the linear dependency, the amplitude falling later with increasing tonicity. The LR was abolished at tonicities exceeding 3 times the standard. In hypertonic conditions the twitch tension was reduced and extended, but showed the same dependency on sarcomere length as in standard conditions. The amplitude showed the same dependency on tonicity as the LR amplitude. The time course extended in a non-linear way with growing tonicity. In hypertonic conditions the resting tension was higher than or the same as in standard conditions, and the dependency on sarcomere length was the same.