RESUMEN

The DARWIN observatory is a proposed next-generation experiment with 40 tonnes of liquid xenon as an active target in a time projection chamber. To study challenges related to the construction and operation of a multi-tonne scale detector, we have designed and constructed a vertical, full-scale demonstrator for the DARWIN experiment at the University of Zurich. Here, we present the first results from a several-months run with 343kg of xenon and electron drift lifetime and transport measurements with a 53cm tall purity monitor immersed in the cryogenic liquid. After 88days of continuous purification, the electron lifetime reached a value of (664±23)µs. We measured the drift velocity of electrons for electric fields in the range (25-75) V/cm, and found values consistent with previous measurements. We also calculated the longitudinal diffusion constant of the electron cloud in the same field range, and compared with previous data, as well as with predictions from an empirical model.

RESUMEN

For the first time, a small dual-phase (liquid/gas) xenon time projection chamber was equipped with a top array of silicon photomultipliers for light and charge readout. Here we describe the instrument in detail, as well as the data processing and the event position reconstruction algorithms. We obtain a spatial resolution of ∼ 1.5 mm in the horizontal plane. To characterise the detector performance, we show calibration data with internal 83 m Kr and 37 Ar sources, and we detail the production of the latter as well as its introduction into the system. We finally compare the observed light and charge yields down to electronic recoil energies of 2.82 keV to predictions based on NEST v2.0.

Asunto(s)

RESUMEN

This article elucidates changes in the recommended diagnostics and therapy of fibromyalgia (FM). The recommendations from major internationally recognized guidelines are compared with the newest recommendations of the European League Against Rheumatism (EULAR) that in contrast to the guidelines surprisingly recommend physical exercise after patient education for all FM patients. The differences between the guidelines and the EULAR recommendations are critically discussed in particular because although the literature referred to in the guidelines was similar, the analysis led to different recommendations. Finally, we try to predict how patients will be treated 10 years from now, for which knowledge from the guidelines and the initial approaches that diagnosed heterogeneity in FM are included. Empirically based questions will drive mechanism-based approaches as opposed to simply reacting to symptoms, in order to meet the challenge of an individual, mechanism-oriented treatment.

Asunto(s)

RESUMEN

BACKGROUND: The etiology of fibromyalgia syndrome is not yet fully understood. Current hypotheses suggest a potential role of gamma-hydroxybutyrate (GHB) in influencing endocrinological abnormalities in patients with fibromyalgia. OBJECTIVE: The aim of the study was to investigate whether low dose GHB as a growth-hormone releasing substance reduces pain intensity and improves depressive mood, physical impairment and sleep quality in outpatients with fibromyalgia. Additionally, adverse events were recorded. MATERIAL AND METHODS: The pilot study was conducted in the outpatient clinic for pain at the clinic for anesthesiology and surgical intensive care of the Charité Universitätsmedizin Berlin. In the study 25 female patients with fibromyalgia according to the criteria of the American College of Rheumatology were randomized into 2 groups. Over 15 weeks patients of the intervention group received 25 mg/kg body weight oral GHB before going to bed and were compared with a placebo control group. In addition, all patients participated in operant behavioral pain treatment in a group setting. Dependent variables were pain intensity, depressive mood, physical impairment and quality of sleep. RESULTS: There were no group differences in the course of pain intensity (p = 0.61), depressive mood (p = 0.16), physical impairment (p = 0.25) and quality of sleep (p = 0.44); however, all symptoms improved across the groups from pretherapy to posttherapy. Low dose GHB did not increase growth hormone blood concentrations. The number of adverse events that were reported more than two times was similar in both groups. DISCUSSION: Administration of low dose GHB did not yield clinical improvements in female outpatients with fibromyalgia. General improvement in the course of treatment may have resulted from operant behavioral pain therapy. Future studies on GHB should control hypothetical risk factors for identification of non-responders.

Asunto(s)

RESUMEN

The interaction of cardiovascular dynamics and pain perception is an important component of intrinsic pain regulation. In healthy subjects acute pain stimuli cause increased sympathetic arousal and increased mean arterial pressure. Arterial baroreceptors sense phasic blood pressure changes and relay the information to the lower brainstem via the dorsomedial nucleus tractus solitarius (dmNTS). Projections in the brainstem and also higher cortical areas result in elevation of blood pressure as part of the autonomic nervous system as well as modulation of sleep, anxiety and pain. In healthy subjects there is an inverse relationship between blood pressure and pain sensitivity but this relationship is impaired in chronic pain patients. Persistent stress, pain behavior and classical and operant conditioning mechanisms reduce baroreflex sensitivity (BRS) and dmNTS activity in a subgroup of patients. This leads to a decrease of autonomic regulatory function as well as reduced pain inhibition. Importantly, baroreflex function can be modulated by cognitive and affective processes. This article reviews the role of the baroreflex arc as a possible crucial factor in the development and maintenance of chronic pain. The importance of learning mechanisms is described. Mechanism-based individualized treatment approaches for patients with hypertensive stress reactivity are also critically discussed.

Asunto(s)

RESUMEN

BACKGROUND: Determination of psychophysiological effects of operant behavioural (OBT) and cognitive behavioural treatment (CBT) for fibromyalgia patients. METHODS: One hundred and fifteen female patients randomized to OBT (N = 43), CBT (N = 42), or whole-body infrared heat (IH) (N = 30) were compared before and after group treatment as well as at 6- and 12-month follow-ups using intent-to-treat analysis (12 drop-outs). Thirty matched pain-free controls (CON) served as reference group for the initial psychophysiological analysis. Surface electromyogram (EMG), blood pressure, heart rate (HR) and skin conductance levels (SCL) were continuously recorded during adaptation, baseline, social conflict, mental arithmetic and relaxation tasks. RESULTS: At baseline, fibromyalgia patients showed higher SCL and HR, lower diastolic blood pressure and EMG in comparison to controls. OBT and CBT compared to IH significantly reduced pain intensity [OBT: effect size (ES) = 1.21 CI: 0.71-1.71, CBT: ES = 1.23, CI: 0.72-1.74]. OBT increased diastolic blood pressure [ES = 1.13, CI: 0.63-1.63 and CBT reduced SCL (ES) = -0.66, CI: -1.14-0.18] 12 months after treatment. Both CBT and OBT significantly increased EMG levels (OBT: ES = 0.97, CI: 0.48-1.46, CBT: ES = 1.17, CI: 0.67-1.68). In contrast, the IH group did not show any significant changes in the psychophysiological parameters. CONCLUSION: Increased diastolic blood pressure and decreased pain after OBT suggest a reactivation of baroreflex-mechanisms in fibromyalgia and a normalization of the blood pressure and pain functional relationship. Reduced SCL following CBT may indicate reduced general arousal levels. Increased muscle tension after CBT and OBT suggest a normalization of physical parameters. The reduction in pain seems to be mediated by different psychophysiological processes, providing support for mechanism-based treatments might be indicated for CBT and OBT. WHAT DOES THIS STUDY ADD?: Differential physiological stress responses followed different psychological interventions. While OBT influenced blood pressure by restoring blood pressure-pain interaction, CBT reduced stress-related sudomotor activity. These results implicate specific mediating mechanisms in fibromyalgia suggesting a basis for matching based on specific patient psychophysiological features.

Asunto(s)

RESUMEN

The current article reviews the cognitive-behavioral (CB) and operant-behavioral perspectives on chronic pain and suggests an answer to the question why changes in behaviors, attitudes, and emotions are associated with decreases in pain severity and impact discussing potential psychobiological mechanisms that may underlie cognitive and behavioral techniques. The impact of learning such as classical and operant conditioning in behaviors and physical responses including baroreflex sensitivity (BRS), as well as the influence of cognitions on pain perception and impact will be presented to explain general efficacy of cognitive-behavior therapy (CBT) and operant-behavioral therapy (OBT) in the treatment of people with fibromyalgia (FM) describing some of the limitations of published outcome studies. We discuss advances in moderation and mediation of treatment outcomes. Lastly, we will discuss the need for research that takes into account evidence-based medicine, methods that address treatment responders and non-responders, individual trajectories, how we might advance and refine CBT and OBT, and strategies related to relapse prevention, maintenance, and adherence-enhancement taking advantage of evolving, technological methods of service delivery. We provide recommendations of how to move forward in approaching studies of CBT and OBT efficacy as a function of better understanding of patient characteristics and contextual factors. We advocate for the potential of the CB perspective and principle of learning for all health care providers regardless of discipline or training and will give examples for making more effective the patient-rheumatologist-relationship by using the principles discussed.

Asunto(s)

RESUMEN

BACKGROUND: The scheduled update to the German S3 guidelines on fibromyalgia syndrome (FMS) by the Association of the Scientific Medical Societies ("Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften", AWMF; registration number 041/004) was planned starting in March 2011. MATERIALS AND METHODS: The development of the guidelines was coordinated by the German Interdisciplinary Association for Pain Therapy ("Deutsche Interdisziplinären Vereinigung für Schmerztherapie", DIVS), 9 scientific medical societies and 2 patient self-help organizations. Eight working groups with a total of 50 members were evenly balanced in terms of gender, medical field, potential conflicts of interest and hierarchical position in the medical and scientific fields. Literature searches were performed using the Medline, PsycInfo, Scopus and Cochrane Library databases (until December 2010). The grading of the strength of the evidence followed the scheme of the Oxford Centre for Evidence-Based Medicine. RESULTS: Current data do not identify distinct etiologic or pathophysiological factors mediating development of FMS. The development of FMS is associated with inflammatory rheumatic diseases (EL2b), with gene polymorphisms of the 5-hydroxytryptamine (HT)(2) receptor (EL3a), lifestyle factors (smoking, obesity, lack of physical activity; EL2b), physical and sexual abuse in childhood and adulthood (EL3a). CONCLUSION: FMS is most likely the result of various pathogenetic factors and pathophysiological mechanisms. The English full-text version of this article is available at SpringerLink (under "Supplemental").

Asunto(s)

RESUMEN

Due to its complexity, there is currently an incomplete understanding of temporomandibular joint (TMJ) function, especially in relation to the morphological interplay of the condyle and the disc as well as the disc, the Os temporale and the lateral pterygoid muscle. This also holds true for synovial flow and synovial pumps, the existence of which we postulate and for which we present a theory of their mechanism. In view of the complexity of mandibular movements and the morphology and function of the TMJ, we need to know how precisely a reconstruction of the TMJ, if necessary, must be adapted to nature. An analysis of the morphology of the functional states of the mandible, as well as the synovial pump system, should at least provide a basis for moulding reconstructions.

Asunto(s)

RESUMEN

BACKGROUND AND OBJECTIVE: One way of determining the direction of growth of the mandible is to consider the temporomandibular joint and movement of the mandible as a four-joint gear system, regarding growth then as an extension of the gear system. Our aim was to examine any correlations between the type of biomechanical growth extension and change in the maxilomandibular relation after Class II therapy. SUBJECTS AND METHODS: A total of 130 lateral cephalograms-before and after orthodontic treatment-were available from 65 adolescent class II patients with open bite or deep bite. The two lateral cephalograms from each patient were superimposed on the occlusal plane. Cephalometric values and the vertical base point deviation were determined from biomechanical analyses, together with three distances and three angles. RESULTS: No correlation between the cephalometric data and distances or angles were observed. Although there were no significant differences in the distances, we did note significant differences in all three angles (p < 0.05). CONCLUSION: If gear system extension during growth is considered, this can be interpreted as meaning that the occlusal plane of those patients with an initially open bite dropped during treatment, but that it rose in patients with an initially deep bite.

Asunto(s)

RESUMEN

OBJECTIVE: The heterogeneity of cognitive-behavioral patterns in patients with fibromyalgia (FM) has been proposed to underlie the variability in treatment outcomes. It has previously been shown that pain-avoidance and pain-persistence treatments tailored to the patient's pattern are effective in improving physical and psychological functioning and overall impact in high-risk patients with heightened psychological distress. In the present study, the cognitive-behavioral effects of these treatments were evaluated to provide insight into the main proposed mechanisms, specifically pain-avoidance behaviors and activity pacing in the pain-avoidance and pain-persistence treatments, respectively. METHODS: High-risk FM patients were classified into 2 groups, pain avoidance and pain persistence, and randomized in groups to the relevant treatment or waiting-list control condition. The pain-avoidance and pain-persistence treatments both comprised 16 twice-weekly sessions of cognitive-behavioral therapy and exercise training. Cognitive--behavioral factors assessed at pre- and posttreatment and 6 months of followup were evaluated using linear mixed models. RESULTS: A significant treatment effect was found for pain-avoidance behavior in the pain-avoidance treatment and for activity pacing in the pain-persistence treatment, showing improvements in the treatment condition relative to the controls. Furthermore, the effect on functioning was mediated by changes in pain-avoidance behavior in the pain-avoidance treatment and by changes in activity pacing in the pain-persistence treatment. Both treatments also showed significant improvements in other relevant cognitive-behavioral factors. CONCLUSION: Both the pain-avoidance and pain-persistence treatments are effective in improving cognitive-behavioral factors in high-risk FM patients. Pain-avoidance behavior and activity pacing might be important mediating mechanisms for beneficial outcomes in pain-avoidance and pain-persistence treatments, respectively.

Asunto(s)

RESUMEN

The motion patterns of mandibular points were recorded in vivo in closed, free movements of the mandible parallel to the sagittal-vertical plane. The points ran along loops which were valued by their area and length. All points whose loops included the same area under regarding the sense of circulation formed a straight line. Lines belonging to different areas were parallel. When the absolute areas of the oops were plotted for particular points a hollow depression with two minima resulted. The point that showed the lowest minimum in the depression corresponded to the position of the neuromuscular mandibular axis of rotation. The points running along equal loop lengths formed elliptical lines with a minimum below the condyle. The lines of constant loop area and loop length were overlaid with lateral radiographs, to match the patterns of motion with anatomical structures. The mandibular axis of rotation lay mostly cranial anterior of the condyle whereas the point with the shortest path lay mainly below this axis point, inside the bony structures. The row of teeth in the maxilla was found to be located below the line of minimal loop lengths. The cervical spine was arranged along the depression of the minimal absolute areas.

Asunto(s)

RESUMEN

OBJECTIVE: To write a systematic review on the etiology and pathophysiology of the fibromyalgia syndrome (FMS) and of chronic widespread pain (CWP). METHODS: An interdisciplinary level-3 guideline (i.e. systematic literature search and assessment, logic analysis, formal consensus procedure) for the diagnosis and therapy of FMS was created in cooperation with 10 medical and psychological societies and 2 patient self-help organizations. A literature search was performed covering all available review articles on the etiology and pathophysiology of FMS and CWP using the Cochrane Collaboration Reviews (1993-12/2006), Medline (1980-2006), PsychInfo (1966-12/2006), and Scopus (1980-12/2006). For the assignment of evidence classes the system of the Oxford Centre for Evidence-Based Medicine was applied. Consensus was achieved by a multi-step nominal group procedure. RESULTS: FMS aggregates in families (evidence level 2c). Physical and psychological stress at the workplace are risk factors for the development of CWP and FMS. Affective disorders are risk factors for the development and maintenance of FMS. Operant learning mechanisms and sensitization are risk factors for the chronification of FMS (evidence levels 2b). Several factors are associated with the pathophysiology of FMS, but the causal relationship is unclear. This includes alterations of central pain pathways, hyporeactivity of the hypothalamus-pituitary-adrenal axis, increased systemic pro-inflammatory and reduced anti-inflammatory cytokine profiles and disturbances in the dopaminergic and serotonergic systems. CONCLUSIONS: FMS is the common final product of various etiological factors and pathophysiological mechanisms.

Asunto(s)

RESUMEN

BACKGROUND: A guideline for the treatment and diagnostic procedures in fibromyalgia syndrome (FMS) was developed in cooperation with 10 German medical and psychological associations and 2 patient self-help groups. METHODS: A systematic literature search including all controlled studies of evaluated multicomponent therapy was performed in the Cochrane Collaboration Reviews (1993-12/2006), Medline (1980-12/2006), PsychInfo (1966-12/2006) and Scopus (1980-12/ 2006). Levels of evidence were assigned according to the classification system of the Oxford Centre for Evidence-Based Medicine. Grading of the strengths of recommendations was done according to the German program for disease management guidelines. Standardized procedures to reach a consensus on recommendations were used. RESULTS: Cognitive and operant behavioral therapy is strongly recommended (grade A). Guided imagery/hypnotherapy and written emotional disclosure are recommended (grade B). CONCLUSIONS: Psychotherapeutic programs tailored to FMS subgroups should be developed and tested.

Asunto(s)

RESUMEN

In 2005, the Physikalisch-Technische Bundesanstalt (PTB) and the QSA Global GmbH (QSA) organised a national comparison of (99m)Tc solution measurements. The purpose of this comparison was to gain information on the quality of routine activity measurements carried out in the field of nuclear medicine in Germany. In addition to this, an ampoule containing a calibrated (99m)Tc solution was sent from PTB to the Bureau International des Poids et Mesures (BIPM) to have the activity result entered into the database of the International Reference System (SIR), and thus demonstrating traceability of the measurements to the SI. In the following, we will report on the activity standardisation carried out at the PTB, and on the way in which the national comparison had been organised, and we will provide information on the analysis as well as on its results.

Asunto(s)

RESUMEN

OBJECTIVE: Central pain processing is altered in patients with fibromyalgia syndrome (FMS). The serotonin metabolism, especially the 5-HT3 receptor, seems to play an important role. METHODS: We investigated the effect of the local injection of the 5-HT3 receptor antagonist tropisetron on the perception and central processing of pain in FMS patients using painful mechanical stimulation and functional magnetic resonance imaging (fMRI) within the framework of a pre-/posttreatment double-blind design. RESULTS: In the contralateral primary somatosensory cortex, contralateral posterior insula, and anterior cingulate cortex, we found that the activation was significantly reduced after treatment. On average, patients rated the stimulation-induced pain intensity as stronger in the session after treatment compared to before treatment, although the individual data revealed a heterogeneous pattern. All patients showed sensitisation during the painful stimulation, which was not influenced by the treatment. CONCLUSIONS: Both the sensory-discriminative and motivational-affective components of pain as measured by fMRI were altered by tropisetron.

Asunto(s)

RESUMEN

This contribution presents the psychosocial, psychopathological, psycho- and elektrophysiological as well as endocrine results in the aetiopathogenesis of fibromyalgia syndrome (FMS). Three subgroups could be differentiated based on psychosocial learning processes. They differ in pain intensity and interference, affective distress, activity and spouse responses. They influence pain behavior and CNS activity in the sense of operant conditioning. The relationship between dysregulated pain modulation in the CNS and endocrine dysregulation of the HPA-axis, which seems to be relevant for the autonome hyporeaction of muscle and blood pressure, are discussed. The "dynamic processing model for FMS" is presented.

Asunto(s)