2,665 research outputs found

    Adaptive logics: a parametric approach

    Full text link

    Astronomical Observations

    Get PDF
    OBJECTIVE: To investigate the role of Fcg receptor (FcgR) genes in susceptibility to rheumatoid arthritis (RA) using family based studies, to examine possible interactions between FcgR genotypes and the shared epitope (SE), and to assess linkage disequilibrium between FcgR loci. METHODS: Association studies were performed in 95 Caucasian, single-case, nuclear Caucasian families with both parents alive using haplotype based haplotype relative risk (HHRR) and transmission disequilibrium test (TDT) statistics. Three FcgR polymorphisms (FcgRIIA-131H/R, FcgRIIIA-158V/F, and FcgRIIIB-NA1/NA2) were genotyped using polymerase chain reaction methods. Linkage analysis was performed using 3 microsatellite markers (D1S498, D1S2844, D1S2762) flanking the FcgR region in an independent set of 90 Caucasian, multiple-case families. Potential effects of disease heterogeneity, including sex and the presence of rheumatoid factor, SE, and erosive or nodular disease, were taken into account in the analysis. Logistic regression analysis was performed to determine whether FcgR alleles are independent risk factors for the susceptibility to and/or severity of RA. Linkage disequilibrium was calculated using pairwise linkage disequilibrium statistics. RESULTS: HHRR and TDT analysis showed no evidence of preferential transmission of any FcgR alleles studied, and there were no important associations with any given disease phenotype. Moreover, neither linkage to microsatellite markers close to the FcgR genes on chromosome 1 nor linkage disequilibrium between FcgR loci was present in our population. The distribution of inherited genotypes provided evidence for an interaction between the SE and the FcgRIIIA-158V allele and between the SE and the FcgRIIIA-158V-FcgRIIA-131H 2-locus haplotype since the combined presence of these factors increased the susceptibility to RA (OR 4.13, 95% CI 1.6-10.62 and OR 2.83, 95% CI 1.25-6.38, respectively). However, regression analysis showed that neither the 158V allele nor the 158V-131H haplotype contributed as independent factors to susceptibility or severity of RA. CONCLUSION: Isolated FcgR genes do not play a major independent role in susceptibility to RA. To a limited extent, the presence of high-binding alleles at the FcgRIIIA locus or at the FcgRIIIA-FcgRIIA haplotype might predispose to RA in SE positive individuals

    Identifying disrupted biological factors and patient-tailored interventions for chronic fatigue in adolescents and young adults with Q-Fever Fatigue Syndrome, Chronic Fatigue Syndrome and Juvenile Idiopathic Arthritis (QFS-study): study protocol for a randomized controlled trial with single-subject experimental case series design

    Get PDF
    Background: Chronic fatigue with a debilitating effect on daily life is a frequently reported symptom among adolescents and young adults with a history of Q-fever infection (QFS). Persisting fatigue after infection may have a biological origin with psychological and social factors contributing to the disease phenotype. This is consistent with the biopsychosocial framework, which considers fatigue to be the result of a complex interaction between biological, psychological, and social factors. In line, similar manifestations of chronic fatigue are observed in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and juvenile idiopathic arthritis (JIA). Cognitive behavioral therapy is often recommended as treatment for chronic fatigue, considering its effectiveness on the group level. However, not everybody benefits on the individual level. More treatment success at the individual level might be achieved with patient-tailored treatments that incorporate the biopsychosocial framework. Methods: In addition to biological assessments of blood, stool, saliva, and hair, the QFS-study consists of a randomized controlled trial (RCT) in which a single-subject experimental case series (N=1) design will be implemented using Experience Sampling Methodology in fatigued adolescents and young adults with QFS, CFS/ME, and JIA (aged 12–29). With the RCT design, the effectiveness of patient-tailored PROfeel lifestyle advices will be compared against generic dietary advices in reducing fatigue severity at the group level. Pre-post analyses will be conducted to determine relevance of intervention order. By means of the N=1 design, effectiveness of both advices will be measured at the individual level. Discussion: The QFS-study is a comprehensive study exploring disrupted biological factors and patient-tailored lifestyle advices as intervention in adolescent and young adults with QFS and similar manifestations of chronic fatigue. Practical or operational issues are expected during the study, but can be overcome through innovative study design, statistical approaches, and recruitment strategies. Ultimately, the study aims to contribute to biological research and (personalized) treatment in QFS and similar manifestations of chronic fatigue. Trial registration: Trial NL8789. Registered July 21, 2020

    Dynamic modeling of experience sampling methodology data reveals large heterogeneity in biopsychosocial factors associated with persistent fatigue in young people living with a chronic condition

    Get PDF
    Objective: To evaluate associations between self-reported biopsychosocial factors and persistent fatigue with dynamic single-case networks. Methods: 31 persistently fatigued adolescents and young adults with various chronic conditions (aged 12 to 29 years) completed 28 days of Experience Sampling Methodology (ESM) with five prompts per day. ESM surveys consisted of eight generic and up to seven personalized biopsychosocial factors. Residual Dynamic Structural Equation Modeling (RDSEM) was used to analyze the data and derive dynamic single-case networks, controlling for circadian cycle effects, weekend effects, and low-frequency trends. Networks included contemporaneous and cross-lagged associations between biopsychosocial factors and fatigue. Network associations were selected for evaluation if both significant (α < 0.025) and relevant (β ≥ 0.20). Results: Participants chose 42 different biopsychosocial factors as personalized ESM items. In total, 154 fatigue associations with biopsychosocial factors were found. Most associations were contemporaneous (67.5%). Between chronic condition groups, no significant differences were observed in the associations. There were large inter-individual differences in which biopsychosocial factors were associated with fatigue. Contemporaneous and cross-lagged associations with fatigue varied widely in direction and strength. Conclusions: The heterogeneity found in biopsychosocial factors associated with fatigue underlines that persistent fatigue stems from a complex interplay between biopsychosocial factors. The present findings support the need for personalized treatment of persistent fatigue. Discussing the dynamic networks with the participant can be a promising step towards tailored treatment. Trial registration: No. NL8789 (http://www.trialregister.nl

    Paediatric short fatigue questionnaire, a 4-item fatigue questionnaire for children

    Get PDF
    Objective: To investigate whether a paediatric Short Fatigue Questionnaire (pSFQ) assesses a valid construct for subjective fatigue, to assess its psychometric properties and provide a cut-off score for severe fatigue in children. Methods: The pSFQ consists of 4 items from the Checklist Individual Strength-8 (CIS-8). Data of previous studies using the CIS-8 were used to assess the pSFQ in healthy children (n = 316), children with chronic fatigue syndrome (n = 173), and children with a chronic disease (n = 442). All children were 12–18 years old. Confirmatory factor analysis (CFA) was performed, followed by Cronbach alpha's to investigate internal consistency, and Spearman's correlations to assess construct validity. With ROC analysis, we determined a cut-off score for severe fatigue and provide normative data on the pSFQ for children with and without a chronic disease. Results: CFA confirmed a one-factor model in the pSFQ representing subjective fatigue. Cronbach's alpha ranged from good to excellent (0.84–0.94), as did construct validity (−0.76 and − 0.87 for correlation with two other fatigue measurements). ROC analysis delivered a cut-off score of ≥21, with a sensitivity of 93.9% and specificity of 96.2% for severe fatigue. Normative data for children with and without a chronic disease showed similar patterns compared to other fatigue questionnaires. Conclusion: The pSFQ is a practical and reliable screening instrument for severe fatigue in children with and without a chronic disease, and effectively reduces the questionnaire length with 50% compared to the conventional CIS-8

    Lower hair cortisol concentration in adolescent and young adult patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Q-Fever Fatigue Syndrome compared to controls

    Get PDF
    Background: In patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), momentary cortisol concentrations in blood, urine, and saliva are lower compared to healthy controls. Long-term cortisol concentration can be assessed through hair, but it is unclear whether these concentrations are also lower. Additionally, it is unknown if lower cortisol extends to other patients suffering from persistent fatigue and how hair cortisol concentration (HCC) relates to fatigue levels. Therefore, this study examines HCC in fatigued patients with ME/CFS, Q fever Fatigue Syndrome (QFS), Post-COVID-19 condition (PCC), and Juvenile Idiopathic Arthritis (JIA). Methods: Adolescent and young adult patients with ME/CFS (n=12), QFS (n=20), PCC (n=8), JIA (n=19), and controls (n=57) were included. Patients participated in a randomized cross-over trial (RCT) targeting fatigue through lifestyle and dietary self-management strategies. HCC was measured pre-post RCT in patients and once in controls, quantified using a LC-MS/MS-based method. Fatigue severity was measured with the Checklist Individual Strength-8. HCC was compared between groups with ANOVAs. Relations between HCC, fatigue severity, and other variables were investigated using linear regression analyses. Results: The ME/CFS (p=.009) and QFS (p=.047) groups had lower HCC compared to controls. Overall, HCC was negatively associated with the presence of symptoms related to chronic fatigue syndromes (e.g., sleeping issues, often feeling tired, trouble thinking clearly; β=-0.018, p=.035), except in the QFS group (β=.063, p<.001). Baseline HCC did not predict fatigue improvement during the RCT (p=.449), and HCC increased during the trial (Mdif=.076, p=.021) regardless of clinically relevant fatigue improvement (p=.658). Conclusion: Lower cortisol concentration can also be observed in the long-term. Lower HCC is not limited to ME/CFS, as it was also observed in QFS. The role of cortisol may differ between these diagnoses and appears to be unrelated to fatigue levels

    Minimally invasive mitral valve surgery: a systematic safety analysis

    Get PDF
    Objective Minimally invasive surgery is increasingly adopted as an alternative to conventional sternotomy for mitral valve pathology in many centres worldwide. A systematic safety analysis based on a comprehensive list of pre-specified 30-day complications defined by the Mitral Valve Academic Consortium (MVARC) criteria is lacking. The aim of the current study was to systematically analyse the safety of minimally invasive mitral valve surgery in our centre based on the MVARC definitions. Methods All consecutive patients undergoing minimally invasive mitral valve surgery through right mini-thoracotomy in our institution within 10 years were studied retrospectively. The primary outcome was a composite of 30-day major complications based on MVARC definitions. Results 745 patients underwent minimally invasive mitral valve surgery (507 repair, 238 replacement), with a mean age of 62.9±12.3 years. The repair was successful in 95.8%. Overall 30-day mortality was 1.2% and stroke rate 0.3%. Freedom from any 30-day major complications was 87.2%, and independent predictors were left ventricular ejection fraction <50% (OR 1.78; 95% CI 1.02 to 3.02) and estimated glomerular filtration rate <60 mL/min/1.73 m 2 (OR 1.98; 95% CI 1.17 to 3.26). Conclusions Minimally invasive mitral valve surgery is a safe technique and is associated with low 30-day mortality and stroke rate
    corecore