Publications by authors named "Schuller W"

Purpose: The minimal important change (MIC) is defined as the smallest within-individual change in a patient-reported outcome measure (PROM) that patients on average perceive as important. We describe a method to estimate this value based on longitudinal confirmatory factor analysis (LCFA). The method is evaluated and compared with a recently published method based on longitudinal item response theory (LIRT) in simulated and real data.

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We evaluated the responsiveness of the Patient Reported Outcome Information System Pain Interference item bank in patients with musculoskeletal pain by testing predefined hypotheses about the relationship between the change scores on the item bank, change scores on legacy instruments and Global Ratings of Change (GRoC), and we estimated Minimal Important Change (MIC). Patients answered the full Dutch-Flemish V1.1 item bank.

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Background: In The Netherlands, low back pain patients can consult physicians specialized in musculoskeletal (MSK) medicine. Previous studies have reported on the characteristics of patients consulting MSK physicians, and the treatment options used. There are no studies yet reporting on the course of Low Back Pain (LBP) after treatment by musculoskeletal (MSK) physicians in The Netherlands.

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Introduction: Transition ratings (TRs) are single item measures which ask patients to report on their health change. They allow for a simple assessment of improvement or deterioration and are frequently used as an "anchor" to determine interpretation thresholds on a patient-reported outcome measure (PROM). Despite their widespread use, a routinely applicable method to assess their reliability is lacking.

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We studied the psychometric properties of the 39-item v1.1 Dutch-Flemish Patient-Reported Outcomes Measurement Information System Pain Behavior item bank in a sample of 1,602 patients with musculoskeletal complaints. We evaluated the assumptions of the underlying item response theory (IRT) model (unidimensionality and local dependency with confirmatory factor analyses), and monotonicity with scalability coefficients).

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Purpose: To investigate the validity of comparisons across patients with different musculoskeletal disorders and persons from the general population by evaluating differential item functioning (DIF) for the PROMIS physical function (PROMIS-PF), pain interference (PROMIS-PI), and pain behavior (PROMIS-PB) item banks.

Methods: Patients with chronic pain, rheumatoid arthritis (RA), or osteoarthritis (OA); patients receiving physiotherapy (PT); and persons from the Dutch general population completed the full Dutch-Flemish PROMIS-PF (121-items), PROMIS-PI (40-items), or PROMIS-PB (39-items) banks. DIF was assessed with ordinal logistic regression models and McFadden's pseudo R-change of ≥ 2% as critical value.

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Study Design: A cross-sectional study.

Objective: The aim of this study was to validate the Dutch-Flemish PROMIS Pain Interference item bank in patients with musculoskeletal complaints.

Summary Of Background Data: PROMIS item banks have been developed and validated in the US.

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Background: Various health care professionals apply Spinal Manipulative Treatment (SMT) in daily practice. While the characteristics of chiropractors and manual therapists and the characteristics of their patient populations are well described, there is little research about physicians who use SMT techniques. A distinct group of physicians in The Netherlands has been trained in musculoskeletal (MSK) medicine, which includes the use of SMT.

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Melanoma is a malignant tumor in which UVA (320-400 nm) radiation is considered to be an important risk factor. But the role of UVA in melanoma progression toward an invasive phenotype is still not adequately investigated. For most proliferating tumor cells the preference of aerobic glycolysis has been described as the Warburg effect.

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Background: Reported values of the minimal important change (MIC) and the smallest detectable change (SDC) for the neck disability index (NDI) differ strongly, raising questions about the generalizability of these parameters. The SDC and the MIC are possibly influenced by the study design or by the study population. We studied the influence of the type of anchor, the definition of improvement and population characteristics on the SDC and the MIC of the NDI.

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UVR suppresses the immune system through the induction of regulatory T cells (Tregs). UVR-induced DNA damage has been recognized as the major molecular trigger involved, as reduction of DNA damage by enhanced repair prevents the compromise to the immune system by UVR. Nevertheless, other signaling events may also be involved.

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Background: Suppression of the adaptive immune system by UV radiation plays an important role in photocarcinogenesis. Exacerbation of skin infections has been proposed as a further consequence of UV-induced immunosuppression. Clinically bacterial infections are not a problem.

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Xeroderma pigmentosum (XP) is a genetic disorder characterised by hypo-/hyperpigmentation, increased sensitivity to ultraviolet (UV)-radiation and an up to 2000-fold increased skin cancer risk. Cells from XP-patients are defective in nucleotide excision repair (NER) responsible for repair of UV-induced DNA damage. This defect accounts for their mutator phenotype but does not predict their increased skin cancer risk.

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Background: The regulatory mechanisms underlying tissue specificity are a crucial part of the development and maintenance of multicellular organisms. A genome-wide analysis of promoters in the context of gene-expression patterns in tissue surveys provides a means of identifying the general principles for these mechanisms.

Results: We introduce a definition of tissue specificity based on Shannon entropy to rank human genes according to their overall tissue specificity and by their specificity to particular tissues.

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Objective: The aim of the study was to identify differences in the diagnosis and treatment of nonspecific low back pain among 3 professional groups in the Netherlands: orthomanual physicians, manual therapists, and chiropractors.

Methods: Information was obtained from training materials from professional groups, literature searches, and observation of selected practitioners at work.

Results: In The Netherlands, there are differences in education between the 3 professional groups.

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The aim of this study was to investigate seroprevalences to zoonotic pathogens in hunters, to compare the results with other predisposed occupational groups already investigated and to propose preventive measures. Blood samples were taken from 146 male and 3 female hunters from the provinces of Styria and Burgenland in the south-east of Austria and anamnestic data were obtained using a questionnaire. The serological investigations included the following bacterial, viral and parasitic zoonotic agents or zoonoses, respectively (antibody prevalence rates in brackets): borreliosis (IgG 42%, IgM 7%), brucellosis (1%), chlamydiosis (3%), ehrlichiosis (IgG 15%, IgM 3%), leptospirosis (10%), tularaemia (3%), Q fever (0%), encephalomyocarditis virus (EMCV, 15%), Puumala-Hantavirus (10%), Newcastle Disease virus (4%), Echinococcus multilocularis/E.

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The aim of this study was to investigate the seroprevalences to zoonotic pathogens in hunters, to propose preventive measures and to obtain more information about the occurrence of zoonotic pathogens in local wild animal populations. From 146 male and 3 female hunters originating from the south-eastern Austrian federal states of Styria and Burgenland blood samples were taken and anamnestic data were obtained using a questionnaire. The serological investigations included the following viral, bacterial and parasitic zoonotic agents or zoonoses, respectively (antibody-seroprevalences in brackets): encephalomyocarditis virus (EMCV, 15%), Puumala-Hantavirus (10%), Newcastle Disease virus (NDV, 4%), borreliosis (IgG 42%, IgM 7%), brucellosis (1%), chlamydiosis (3%), ehrlichiosis (IgG 15%, IgM 3%), leptospirosis (10%), tularaemia (3%), Q fever (0%), Echinococcus multilocularis/E.

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The proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-Screen assay) was applied for quantitative determination of total estrogenic activity in 24-h composite effluent samples from 16 municipal and two industrial sewage treatment plants (STPs) in the state of Baden-Württemberg, southwestern Germany. The estrogenic efficacy relative to the positive control, 17beta-estradiol, was between 26 and 74% (median, 48%) for the 16 municipal STPs. Estradiol equivalent concentrations (EEQs) were between 0.

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24 h samples of untreated and treated wastewater were taken in parallel from a modern municipal sewage plant in southern Germany in March and June 1998. After solid phase extraction, total estrogenic activity was quantitatively measured with a miniaturized E-screen assay and the levels of nine estrogenic phenolic chemicals analyzed by HRGC/LRMS. 17Beta-estradiol equivalent concentrations (EEQ) were 58 and 70 ng/l in the influent and 6 ng/l in the effluent, indicating that the load of estrogenic activity of the wastewater was reduced by about 90% in the sewage plant.

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The experimental infection of two goats with Trypanosoma vivax trypanosomes provided samples for analysis using parasitology techniques and antigen-detection enzyme-linked immunosorbent assays (ELISAs) for T. vivax, T. congolense and T.

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A simplified proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-screen assay) was optimized and validated for the sensitive quantitative determination of total estrogenic activity in effluent samples from municipal sewage plants. After solid phase extraction of 1 l sewage on either 0.2 g polystyrene copolymer (ENV+) or 1 g RP-C18 material and removal of the solvent, analysis of the extracts in the E-screen assay could be performed without any clean-up step.

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The E-Screen assay serves as an in vitro tool for the detection of estrogenic activity of chemicals and extracts of environmental samples. Based on the induction of proliferation in human estrogen receptor-positive MCF-7 breast cancer cells we could substantially simplify the assay. As one important step of validation we applied the modified assay for testing nine known xenoestrogens.

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This paper describes the second part of a longtime-study, started in 1987. Serologic investigations for detecting antibodies against Maedi Visna-virus (MVV) were performed, involving an institute own sheep flock. The method used was the immunodiffusiontest.

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The antigen expression of immature erythroid bone marrow cells was studied using two recently generated monoclonal antibodies (mAb), mAb 67A4 and 9C4, with specificities for the epithelial cell adhesion molecule E-cadherin (E-cad; mAb 67A4), and a novel 110 kDa differentiation antigen (mAb 9C4) with unknown molecular structure. Pappenheim staining of FACS-purified cells labeled with mAb 9C4 and anti-glycophorin A (GA) revealed that the majority of the 9C4+GA- and 9C4+GA+ cells consisted of erythroblasts. In contrast, the E-cad-positive population comprised normoblasts and erythroblasts.

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