Agreement, reliability and validity in 3 shoulder questionnaires in patients with rotator cuff disease

Background Self-report questionnaires play an important role as outcome measures in shoulder research. Having an estimate of the measurement error of these questionnaires is of importance when assessing follow-up results after treatment and when planning intervention studies. The aim of this study was to cross-culturally adapt the Norwegian version of the OSS and WORC questionnaire and examine and compare agreement, reliability and construct validity of the disease-specific shoulder questionnaire WORC with two commonly used shoulder questionnaires, SPADI and OSS, in patients with rotator cuff disease. Methods 74 patients with rotator cuff disease were recruited from the outpatient clinic of the Physical Medicine and Rehabilitation Department at Ullevaal University Hospital in Oslo, Norway. A test-retest design was used, and the questionnaires were filled out by the patients at the clinic, with a one week interval between test administrations. Agreement (repeatability coefficient), reliability (ICC) and construct validity were examined and compared for WORC, SPADI and OSS. Results Reliability analysis was restricted to the 55 patients (51 ± 10 yrs) who reported no change between test administrations according to scoring on a global scale. The agreement, reliability and construct validity was moderate for all three questionnaires with ICC ranging from 0.83 to 0.85, repeatability coefficient from 16.1 to 19.7 and Spearman rank correlations between total scores from r = 0.57 to 0.69. There was a lower degree of floor and ceiling effects in SPADI compared to WORC and OSS. Conclusion We conclude that the agreement and reliability of the three shoulder questionnaires examined, WORC index, SPADI and OSS are acceptable and that differences between scores were small. The Norwegian version of the questionnaires is acceptable for assessing Norwegian-speaking patients with rotator cuff disease. The moderate agreement and construct validity should be taken into consideration when assessing follow-up results after treatment and in the planning of prospective studies

Molecular basis for atovaquone binding to the cytochrome bc₁ complex

Atovaquone is a substituted 2-hydroxynaphthoquinone that is used therapeutically to treat Plasmodium falciparum malaria, Pneumocystis carinii pneumonia, and Toxoplasma gondii toxoplasmosis. It is thought to act on these organisms by inhibiting the cytochrome bc1 complex. We have examined the interaction of atovaquone with the bc1 complex isolated from Saccharomyces cerevisiae, a surrogate, nonpathogenic fungus. Atovaquone inhibits the bc1 complex competitively with apparent Ki = 9 nm, raises the midpoint potential of the Rieske iron-sulfur protein from 285 to 385 mV, and shifts the g values in the EPR spectrum of the Rieske center. These results indicate that atovaquone binds to the ubiquinol oxidation pocket of the bc1 complex, where it interacts with the Rieske iron-sulfur protein. A computed energy-minimized structure for atovaquone liganded to the yeast bc1 complex suggests that a phenylalanine at position 275 of cytochrome b in the bovine bc1 complex, as opposed to leucine at the equivalent position in the yeast enzyme, is responsible for the decreased sensitivity of the bovine bc1 complex (Ki = 80 nm) to atovaquone. When a L275F mutation was introduced into the yeast cytochrome b, the sensitivity of the yeast enzyme to atovaquone decreased (Ki = 100 nm) with no loss in activity, confirming that the L275F exchange contributes to the differential sensitivity of these two species to atovaquone. These results provide the first molecular description of how atovaquone binds to the bc1 complex and explain the differential inhibition of the fungal versus mammalian enzymes

Improvement of the Van Lieshout hand function test for tetraplegia using a Rasch analysis.

Item does not contain fulltextSTUDY DESIGN: Cross-sectional study. OBJECTIVE: The Van Lieshout hand function test for tetraplegia (VLT) measures the quality of arm-hand functioning in persons with tetraplegia. It is valid, reliable and responsive. However, it does not satisfy all the criteria for interval level measurement. The present study aims to apply the Rasch model to the VLT short form (VLT-SF) to upgrade its scale type towards interval level, and to verify if the requirements of an objective measure are satisfied in the revised version. SETTING: Eight Dutch Rehabilitation centres. METHODS: The VLT-SF data of 73 tetraplegic patients were Rasch-analysed (RUMM2030 software, RUMM Laboratory Pty Ltd, Perth, Australia) to verify the order of response categories, unidimensionality and reliability of the VLT-SF, and to assess its applicability regardless of (motor) lesion completeness. RESULTS: Seven of the ten VLT-SF items showed disordered response categories. The six original response categories were therefore recoded into three or four categories. After recoding, all items satisfied the model requirement of unidimensionality. The items were relatively well-targeted on the subjects' arm-hand skilled performance measures, leading to a good person separation index (R=0.91). The difficulty hierarchy of the VLT-SF items was invariant across patient subgroups of (motor) lesion completeness. CONCLUSIONS: Provided that response categories are recoded, VLT-SF Rasch analysis showed that the requirements of an objective measure were satisfied. This allows to compare the measurements of different patients quantitatively, and to follow their results over time.1 oktober 201

Effects of dynamic sitting interventions on tissue oxygenation in individuals with spinal cord disorders

Study Design: An explorative cross-sectional study. Objectives: The objective of this study was to investigate the possibility of imposing dynamic sitting behavior on individuals with spinal cord disorders by using the Dynasit chair and to investigate its effect on the (sub-)cutaneous tissue oxygenation. Setting: Rehabilitation Centre het Roessingh, Enschede, the Netherlands. Subjects: Ten male subjects with a spinal cord disorder. Methods: The Dynasit chair, an experimental simulator chair, containing mechanical concepts for postural adjustments, regulation of tuberal load and pelvic rotation, was developed to allow individuals with a spinal cord disorder to sit in a dynamic way. An experiment was carried out in which a dynamic sitting pattern was imposed. The sitting pattern consisted of series of actuated changes in posture, tuberal load and pelvic orientation. Effects of these changes on (sub-)cutaneous buttock tissue oxygenation were investigated by transcutaneous measurement of tissue oxygenation. Results: Nonparametric statistical analyses were carried out on nine subjects that completed the study. Results showed significant positive effects (P<0.05) of actuated changes in tuberal load on the cutaneous and subcutaneous tissue oxygenation. Conclusion: The Dynasit chair is effective in imposing dynamic sitting behavior in individuals with a spinal cord disorder and consequently might reduce the chance of tissue degradatio