88 research outputs found

    An atomic force microscope operating at hypergravity for in situ measurement of cellular mechano-response

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    We present a novel atomic force microscope (AFM) system, operational in liquid at variable gravity, dedicated to image cell shape changes of cells in vitro under hypergravity conditions. The hypergravity AFM is realized by mounting a stand-alone AFM into a large-diameter centrifuge. The balance between mechanical forces, both intra- and extracellular, determines both cell shape and integrity. Gravity seems to be an insignificant force at the level of a single cell, in contrast to the effect of gravity on a complete (multicellular) organism, where for instance bones and muscles are highly unloaded under near weightless (microgravity) conditions. However, past space flights and ground based cell biological studies, under both hypogravity and hypergravity conditions have shown changes in cell behaviour (signal transduction), cell architecture (cytoskeleton) and proliferation. Thus the role of direct or indirect gravity effects at the level of cells has remained unclear. Here we aim to address the role of gravity on cell shape. We concentrate on the validation of the novel AFM for use under hypergravity conditions. We find indications that a single cell exposed to 2 to 3 × g reduces some 30–50% in average height, as monitored with AFM. Indeed, in situ measurements of the effects of changing gravitational load on cell shape are well feasible by means of AFM in liquid. The combination provides a promising technique to measure, online, the temporal characteristics of the cellular mechano-response during exposure to inertial forces

    Event-related potentials indicate motivational relevance of cocaine cues in abstinent cocaine addicts

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    Rationale: Motivational drive and its underlying affect-related states are the core mechanisms that precede the seeking and taking of drugs in substance dependence. Objective: The present study aimed to investigate the motivational relevance of cocaine cues and whether or not an appetitive emotional system is involved employing event-related potential (ERP) measurements. Methods: Cocaine-addicted subjects and healthy controls were exposed to neutral and cocaine-related pictures whilst ERPs were recorded simultaneously over frontal, parietal and midline sites. Results: Patients exhibited ERP amplitude discrepancies between neutral and cocaine-related pictures for N300, late slow positive wave (LSPW) and sustained slow positive wave (SSPW), whilst this effect was absent in control subjects. Differences in neutral and cocaine cue-evoked ERP waves were also found at left frontal sites for LSPW and SSPW in the patient group only. No group-specific cue-evoked ERP amplitudes were observed at parietal and midline sites. Conclusion: The findings confirm the assumption that cocaine cues induce motivational relevance in cocaine-dependent individuals. It is possible that exposure to cocaine cues triggers an appetitive emotional system since left frontal sites are assumed to be involved in processing positive emotional-laden stimuli. The present study provides evidence that the sensitivity of ERP correlates for cocaine cues may be an indicator of motivational and emotional processes in drug-dependent individuals. © Springer-Verlag 2004

    From "being at war" to "getting back on your feet": a qualitative study on experiences of patients with systemic sclerosis treated with hematopoietic stem cell transplantation

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    Objectives:To gain insight into the experiences of patients with diffuse cutaneous systemic sclerosis during and after autologous hematopoietic stem cell transplantation.Methods:Semi-structured interviews were conducted with patients who underwent hematopoietic stem cell transplantation in four university hospitals in the Netherlands. Interviews were transcribed verbatim and thematically analyzed.Results:Nine male and seven female patients were interviewed, median age 47 years (range: 27-68). Patients mentioned their life was severely disrupted before hematopoietic stem cell transplantation and remained unsettled a long time after treatment. Uncertainty because of disease progression, loss of control over health and the sense of time and fear of treatment-related adverse events were common during hospitalization. After hematopoietic stem cell transplantation, patients experienced more physical limitations than they had expected, and recovery took longer and was mentally taxing. Going back to work and finding a new balance in personal relations and social life was complicated. Patients described various strategies to deal with challenges. Family and friends provided essential support, although many experienced a dwindling social circle. Most patients also appreciated peer support. All patients were satisfied with the low threshold for contact with physicians and nurses during hospitalization. However, aftercare focused on medical aspects rather than on psychological well-being and social issues. Moreover, patients would have preferred to be better prepared on what to expect after discharge, and lacked information about self-management, prognosis, optimal recovery, work, sexuality, and family planning.Conclusion:Hematopoietic stem cell transplantation has a major physical and psychological impact on patients with diffuse cutaneous systemic sclerosis. The course of recovery after this intensive therapy was unexpectedly long for some patients and offer of support was far less pro-active post-HSCT compared to pre-HSCT and during HSCT.Analysis and support of clinical decision makin

    Bone Mineral Density in Sjögren Syndrome Patients with and Without Distal Renal Tubular Acidosis

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    Primary Sjögren’s syndrome (pSS) can be complicated by distal renal tubular acidosis (dRTA), which may contribute to low bone mineral density (BMD). Our objective was to evaluate BMD in pSS patients with and without dRTA as compared with healthy controls. BMD of lumbar spine (LS) and femoral neck (FN) was measured in 54 pSS patients and 162 healthy age- and sex-matched controls by dual-energy X-ray absorptiometry (DXA). dRTA was defined as inability to reach urinary pH <5.3 after an ammonium chloride (NH4Cl) test. LS- and FN-BMD were significantly higher in pSS patients compared with controls (1.18 ± 0.21 g/cm2 for patients vs. 1.10 ± 0.18 g/cm2 for controls, P = 0.00

    Treatment decision-making in diffuse cutaneous systemic sclerosis: a patient's perspective

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    Objectives. To examine the treatment decision-making process of patients with dcSSc in the context of haematopoietic stem cell transplantation (HSCT).Methods. A qualitative semi-structured interview study was done in patients before or after HSCT, or patients who chose another treatment than HSCT. Thematic analysis was used. Shared decision-making (SDM) was assessed with the 9-item Shared Decision Making Questionnaire (SDM-Q-9).Results. Twenty-five patients [16 male/nine female, median age 47 (range 27-68) years] were interviewed: five pre-HSCT, 16 post-HSCT and four following other treatment. Whereas the SDM-Q-9 showed the decision-making process was perceived as shared [median score 81/100 (range 49-100)], we learned from the interviews that the decision was predominantly made by the rheumatologist, and patients were often steered towards a treatment option. Strong guidance of the rheumatologist was appreciated because of a lack of accessible, reliable and SSc-specific information, due to the approach of the decision-making process of the rheumatologist, the large consequence of the decision and the trust in their doctor. Expectations of outcomes and risks also differed between patients. Furthermore, more than half of patients felt they had no choice but to go for HSCT, due to rapid deterioration of health and the perception of HSCT as 'the holy grail'.Conclusion. This is the first study that provides insight into the decision-making process in dcSSc. This process is negatively impacted by a lack of disease-specific education about treatment options. Additionally, we recommend exploring patients' preferences and understanding of the illness to optimally guide decision-making and to provide tailor-made information.Analysis and support of clinical decision makin

    B-cell dysregulation in Crohn's disease is partially restored with infliximab therapy

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    Background: B-cell depletion can improve a variety of chronic inflammatory diseases, but does not appear beneficial for patients with Crohn's disease. Objective: To elucidate the involvement of B cells in Crohn's disease, we here performed an 'in depth' analysis of intestinal and blood B-cells in this chronic inflammatory disease. Methods: Patients with Crohn's disease were recruited to study B-cell infiltrates in intestinal biopsies (n = 5), serum immunoglobulin levels and the phenotype and molecular characteristics of blood B-cell subsets (n = 21). The effects of infliximab treatment were studied in 9 patients. Results: Granulomatous tissue showed infiltrates of B lymphocytes rather than Ig-secreting plasma cells. Circulating transitional B cells and CD21low B cells were elevated. IgM memory B cells were reduced and natural effector cells showed decreased replication histories and somatic hypermutation (SHM) levels. In contrast, IgG and IgA memory B cells were normally present and their Ig gene transcripts carried increased SHM levels. The numbers of transitional and natural effector cells were normal in patients who responded clinically well to infliximab. Conclusions: B cells in patients with Crohn's disease showed signs of chronic stimulation with localization to granulomatous tissue and increased molecular maturation of IgA and IgG. Therapy with TNFα-blockers restored the defect in IgM memory B-cell generation and normalized transitional B-cell levels, making these subsets candidate markers for treatment monitoring. Together, these results suggest a chronic, aberrant B-cell response in patients with Crohn's disease, which could be targeted with new therapeutics that specifically regulate B-cell function

    Characteristics of difficult-to-treat rheumatoid arthritis: results of an international survey

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    Objectives: Patients with difficult-to-treat rheumatoid arthritis (RA) remain symptomatic despite treatment according to current European League Against Rheumatism (EULAR) management recommendations. These focus on early phases of the disease and pharmacological management. We aimed to identify characteristics of difficult-to-treat RA and issues to be addressed in its workup and management that are not covered by current management recommendations. Methods: An international survey was conducted among rheumatologists with multiple-choice questions on disease characteristics of difficult-to-treat RA. Using open questions, additional items to be addressed and items missing in current management recommendations were identified. Results: 410 respondents completed the survey: 50% selected disease activity score assessing 28 joints &gt;3.2 OR presence of signs suggestive of active disease as characteristics of difficult-to-treat RA; 42% selected fatigue; 48% selected failure to ≥2 conventional synthetic disease-modifying antirheumatic drugs (DMARDs) AND ≥2 biological/targeted synthetic DMARDs; 89% selected inability to taper glucocorticoids below 5 mg or 10 mg prednisone equivalent daily. Interfering comorbidities, extra-articular manifestations and polypharmacy were identified as important issues missing in current management recommendations. Conclusions: There is wide variation in concepts of difficult-to-treat RA. Several important issues regarding these patients are not addressed by current EULAR recommendations

    Pelvic floor dysfunction is not a risk factor for febrile urinary tract infection in adults

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    OBJECTIVE To determine whether pelvic floor dysfunction (PFD) might be a risk factor for or consequence of febrile urinary tract infection (UTI), as UTI in adults is a common infection in which an underlying urological abnormality is often considered, and as in children, PFD is also thought to have a pathophysiological role in adults with UTI. PATIENTS AND METHODS A multicentre case-control study was conducted at 26 primary-care centres and at six Emergency Departments of regional hospitals. Cases were consecutive patients aged >= 18 years, who presented with febrile UTI. Controls were randomly selected subjects who visited their general practitioner for reasons other than UTI or fever. A validated pelvic floor questionnaire (the Pelvic Floor Inventories Leiden, PelFIs) was used to assess pelvic floor function. RESULTS Between October 2006 and December 2007, 153 cases were included; of these, the completed questionnaires of 102 (response rate 67%) were compared to those of 100 of 110 (response rate 91%) controls. The median age of cases and controls was 65 and 58 years, respectively; 40% of cases and controls were men. The percentage of PelFIs outcomes consistent with PFD were comparable between cases and controls, at 21% vs 23%, respectively (odds ratio 0.9, 95% confidence interval, CI, 0.4-1.78). In the multivariate analysis, comorbidity (odds ratio 4.9, 95% CI 2.2-11.1) and a history of UTI (odds ratio 2.5, 95% CI 1.0-6.1) were independent significant risk factors for febrile UTI, whereas PFD was not (odds ratio 1.0, 0.5-2.2). Within the group of cases, PFD was not associated with bacteriuria during assessment of PelFIs (odds ratio 1.1, 95% CI 0.4-3.5) and inversely related to a history of UTI within the previous year (odds ratio 0.2, 0.1-0.9). CONCLUSIONS PFD is common among adults but it does not seem to be a risk factor for febrile UTI.Immunogenetics and cellular immunology of bacterial infectious disease
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