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| 5. |
- Dawson, Andreas, et al.
(författare)
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Effects of Acute Experimental Stress on Pain Sensitivity and Cortisol Levels in Healthy Participants : A Randomized Crossover Pilot Study
- 2020
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Ingår i: Journal of oral & facial pain and headache. - : Quintessence publishing co inc. - 2333-0384. ; 34:3, s. 281-290
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To investigate pain sensitivity in the masseter muscle and index finger in response to acute psychologic stress in healthy participants. Methods: Fifteen healthy women (23.7 +/- 2.3 years) participated in two randomized sessions: in the experimental stress session, the Paced Auditory Serial Addition Task (PASAT) was used to induce acute stress, and in the control session, a control task was performed. Salivary cortisol, perceived stress levels, electrical and pressure pain thresholds (PTs), and pain tolerance levels (PTLs) were measured at baseline and after each task. Mixed-model analysis was used to test for significant interaction effects between time and session. Results: An interaction effect between time and session occurred for perceived stress levels (P < .001); perceived stress was significantly higher after the experimental task than after the control task (P < .01). No interaction effects occurred for salivary cortisol levels, electrical PTs, or pressure PTLs. Although significant interactions did occur for electrical PTL (P < .05) and pressure PT (P < .001), the simple effects test could not identify significant differences between sessions at any time point. Conclusion: The PASAT evoked significant levels of perceived stress; however, pain sensitivity to mechanical or electrical stimuli was not significantly altered in response to the stress task, and the salivary cortisol levels were not altered in response to the PASAT. These results must be interpreted with caution, and more studies with larger study samples are needed to increase the clinical relevant understanding of the pain mechanisms and psychologic stress.
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| 6. |
- Dawson, Andreas, et al.
(författare)
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The effect of botulinum toxin A on patients with persistent idiopathic dentoalveolar pain : A systematic review
- 2020
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Ingår i: Journal of Oral Rehabilitation. - : John Wiley & Sons. - 1365-2842 .- 0305-182X. ; 47:9, s. 1184-1191
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It has been suggested that botulinum toxin A (BONT-A) is a safe and effective treatment in relieving pain in patients with persistent idiopathic dentoalveolar pain (PIDP).OBJECTIVES: This study aimed to systematically evaluate all the available studies investigating the pain-relieving effects of BONT-A in patients with PIDP.METHODS: A systematic search with specific search terms was made in PubMed, Web of Science and Scopus. Two authors screened titles and abstracts and selected eligible studies for inclusion in the systematic review. The quality of the studies was evaluated by the 12 items Quality Assessment Tool for Observational studies (Pre-Post) Studies with No Control Group, and the level of evidence was assessed according to GRADE.RESULTS: Three observational studies of 3695 identified were included (445 overlapping studies; 3247 excluded studies). All studies were uncontrolled observational studies investigating the pain-relieving effect of BONT-A in patients with PIDP. The included studies had a fair quality (moderate risk of bias) and insufficient level of evidence. The pain reducing effect by BONT-A injections was in average 50% or more in two studies, in one study 3 out of 4 patients became almost pain free.CONCLUSIONS: This systematic review shows that presently the level of scientific evidence is insufficient to evaluate the pain-relieving effect of BONT-A injections in patients with PIDP. There are indications that BONT-A injections could be a possible management option for patients with PIDP that seems to be safe and with few adverse events. There is a need for well-designed placebo-controlled, double-blind RCTs.
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| 7. |
- Lüscher, Bernhard, et al.
(författare)
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ADP-ribosyltransferases, an update on function and nomenclature
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:23, s. 7399-7410
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Tidskriftsartikel (refereegranskat)abstract
- ADP-ribosylation, a modification of proteins, nucleic acids, and metabolites, confers broad functions, including roles in stress responses elicited, for example, by DNA damage and viral infection and is involved in intra- and extracellular signaling, chromatin and transcriptional regulation, protein biosynthesis, and cell death. ADP-ribosylation is catalyzed by ADP-ribosyltransferases (ARTs), which transfer ADP-ribose from NAD+ onto substrates. The modification, which occurs as mono- or poly-ADP-ribosylation, is reversible due to the action of different ADP-ribosylhydrolases. Importantly, inhibitors of ARTs are approved or are being developed for clinical use. Moreover, ADP-ribosylhydrolases are being assessed as therapeutic targets, foremost as antiviral drugs and for oncological indications. Due to the development of novel reagents and major technological advances that allow the study of ADP-ribosylation in unprecedented detail, an increasing number of cellular processes and pathways are being identified that are regulated by ADP-ribosylation. In addition, characterization of biochemical and structural aspects of the ARTs and their catalytic activities have expanded our understanding of this protein family. This increased knowledge requires that a common nomenclature be used to describe the relevant enzymes. Therefore, in this viewpoint, we propose an updated and broadly supported nomenclature for mammalian ARTs that will facilitate future discussions when addressing the biochemistry and biology of ADP-ribosylation. This is combined with a brief description of the main functions of mammalian ARTs to illustrate the increasing diversity of mono- and poly-ADP-ribose mediated cellular processes.
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| 8. |
- Puschmann, Andreas, et al.
(författare)
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Heterozygous PINK1 p.G411S increases risk of Parkinson's disease via a dominant-negative mechanism
- 2017
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Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 140:1, s. 98-117
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Tidskriftsartikel (refereegranskat)abstract
- SEE GANDHI AND PLUN-FAVREAU DOI101093/AWW320 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: It has been postulated that heterozygous mutations in recessive Parkinson's genes may increase the risk of developing the disease. In particular, the PTEN-induced putative kinase 1 (PINK1) p.G411S (c.1231G>A, rs45478900) mutation has been reported in families with dominant inheritance patterns of Parkinson's disease, suggesting that it might confer a sizeable disease risk when present on only one allele. We examined families with PINK1 p.G411S and conducted a genetic association study with 2560 patients with Parkinson's disease and 2145 control subjects. Heterozygous PINK1 p.G411S mutations markedly increased Parkinson's disease risk (odds ratio = 2.92, P = 0.032); significance remained when supplementing with results from previous studies on 4437 additional subjects (odds ratio = 2.89, P = 0.027). We analysed primary human skin fibroblasts and induced neurons from heterozygous PINK1 p.G411S carriers compared to PINK1 p.Q456X heterozygotes and PINK1 wild-type controls under endogenous conditions. While cells from PINK1 p.Q456X heterozygotes showed reduced levels of PINK1 protein and decreased initial kinase activity upon mitochondrial damage, stress-response was largely unaffected over time, as expected for a recessive loss-of-function mutation. By contrast, PINK1 p.G411S heterozygotes showed no decrease of PINK1 protein levels but a sustained, significant reduction in kinase activity. Molecular modelling and dynamics simulations as well as multiple functional assays revealed that the p.G411S mutation interferes with ubiquitin phosphorylation by wild-type PINK1 in a heterodimeric complex. This impairs the protective functions of the PINK1/parkin-mediated mitochondrial quality control. Based on genetic and clinical evaluation as well as functional and structural characterization, we established p.G411S as a rare genetic risk factor with a relatively large effect size conferred by a partial dominant-negative function phenotype.
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| 27. |
- Abdelwahab, Mahmoud Tareq, et al.
(författare)
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Clofazimine pharmacokinetics in patients with TB : dosing implications
- 2020
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Ingår i: Journal of Antimicrobial Chemotherapy. - : OXFORD UNIV PRESS. - 0305-7453 .- 1460-2091. ; 75:11, s. 3269-3277
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Tidskriftsartikel (refereegranskat)abstract
- Background: Clofazimine is in widespread use as a key component of drug-resistant TB regimens, but the recommended dose is not evidence based. Pharmacokinetic data from relevant patient populations are needed to inform dose optimization. Objectives: To determine clofazimine exposure, evaluate covariate effects on variability, and simulate exposures for different dosing strategies in South African TB patients. Patients and methods: Clinical and pharmacokinetic data were obtained from participants with pulmonary TB enrolled in two studies with intensive and sparse sampling for up to 6 months. Plasma concentrations were measured by LC-MS/MS and interpreted with non-Linear mixed-effects modelling. Body size descriptors and other potential covariates were tested on pharmacokinetic parameters. We simulated different dosing regimens to safely shorten time to average daily concentration above a putative target concentration of 0.25 mg/L. Results: We analysed 1570 clofazimine concentrations from 139 participants; 79 (57%) had drug-resistant TB and 54 (39%) were HIV infected. Clofazimine pharmacokinetics were well characterized by a three-compartment model. Clearance was 11.5 L/h and peripheral volume 10500 L for a typical participant. Lower plasma exposures were observed in women during the first few months of treatment, explained by higher body fat fraction. Model-based simulations estimated that a Loading dose of 200 mg daily for 2 weeks would achieve average daily concentrations above a target efficacy concentration 37 days earlier in a typical TB participant. Conclusions: Clofazimine was widely distributed with a Long elimination half-Life. Disposition was strongly influenced by body fat content, with potential dosing implications for women with TB.
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| 28. |
- Abdelwahab, Mahmoud Tareq, et al.
(författare)
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Effect of Clofazimine Concentration on QT Prolongation in Patients Treated for Tuberculosis
- 2021
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Ingår i: Antimicrobial Agents and Chemotherapy. - : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 65:7
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Tidskriftsartikel (refereegranskat)abstract
- Clofazimine is classified as a WHO group B drug for the treatment of rifampin-resistant tuberculosis. QT prolongation, which is associated with fatal cardiac arrhythmias, is caused by several antitubercular drugs, including clofazimine, but there are no data quantifying the effect of clofazimine concentration on QT prolongation. Our objective was to describe the effect of clofazimine exposure on QT prolongation. Fifteen adults drug-susceptible tuberculosis patients received clofazimine monotherapy as 300mg daily for 3 days, followed by 100mg daily in one arm of a 2-week, multiarm early bactericidal activity trial in South Africa. Pretreatment Fridericia-corrected QT (QTcF) (105 patients, 524 electrocardiograms [ECGs]) and QTcFs from the clofazimine monotherapy arm matched with clofazimine plasma concentrations (199 ECGs) were interpreted with a nonlinear mixed-effects model. Clofazimine was associated with significant QT prolongation described by a maximum effect (Emax) function. We predicted clofazimine exposures using 100-mg daily doses and 2 weeks of loading with 200 and 300mg daily, respectively. The expected proportions of patients with QTcF change from baseline above 30 ms (DQTcF. 30) were 2.52%, 11.6%, and 23.0% for 100-, 200-, and 300-mg daily doses, respectively. At steady state, the expected proportion with Delta QTcF of >30 ms was 23.7% and with absolute QTcF of >450 ms was 3.42% for all simulated regimens. The use of loading doses of 200 and 300mg is not predicted to expose patients to an increased risk of QT prolongation, compared with the current standard treatment, and is, therefore, an alternative option for more quickly achieving therapeutic concentrations.
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| 29. |
- Ayoun Alsoud, Rami, et al.
(författare)
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Combined quantitative tuberculosis biomarker model for time-to-positivity and colony forming unit to support tuberculosis drug development
- 2023
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Ingår i: Frontiers in Pharmacology. - : Frontiers Media S.A.. - 1663-9812. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Biomarkers are quantifiable characteristics of biological processes. In Mycobacterium tuberculosis, common biomarkers used in clinical drug development are colony forming unit (CFU) and time-to-positivity (TTP) from sputum samples. This analysis aimed to develop a combined quantitative tuberculosis biomarker model for CFU and TTP biomarkers for assessing drug efficacy in early bactericidal activity studies. Daily CFU and TTP observations in 83 previously patients with uncomplicated pulmonary tuberculosis after 7 days of different rifampicin monotherapy treatments (10-40 mg/kg) from the HIGHRIF1 study were included in this analysis. The combined quantitative tuberculosis biomarker model employed the Multistate Tuberculosis Pharmacometric model linked to a rifampicin pharmacokinetic model in order to determine drug exposure-response relationships on three bacterial sub-states using both the CFU and TTP data simultaneously. CFU was predicted from the MTP model and TTP was predicted through a time-to-event approach from the TTP model, which was linked to the MTP model through the transfer of all bacterial sub-states in the MTP model to a one bacterial TTP model. The non-linear CFU-TTP relationship over time was well predicted by the final model. The combined quantitative tuberculosis biomarker model provides an efficient approach for assessing drug efficacy informed by both CFU and TTP data in early bactericidal activity studies and to describe the relationship between CFU and TTP over time.
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| 30. |
- Bajramaj, Ermira, et al.
(författare)
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The Effect of Microdialysis Catheter Insertion on Glutamate and Serotonin Levels in Masseter Muscle in Patients with Myofascial Temporomandibular Disorders and Healthy Controls
- 2019
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Ingår i: Diagnostics. - : MDPI. - 2075-4418. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Myofascial temporomandibular disorders (TMD) are the most common cause of chronic pain in the orofacial region. Microdialysis has been used to study metabolic changes in the human masseter muscle. The insertion of the microdialysis probe causes acute tissue trauma that could affect the metabolic milieu and thereby influence the results when comparing healthy subjects to those with TMD. This study aimed to investigate the levels of serotonin and glutamate during the acute tissue trauma period in healthy subjects and in patients with TMD. Microdialysis was carried out in 15 patients with TMD and 15 controls, and samples were collected every 20 min during a period of 140 min. No significant alterations of serotonin or glutamate were observed over the 2 h period for the healthy subjects. For the TMD group, a significant decrease in serotonin was observed over time (p < 0.001), followed by a significant increase between 120 and 140 min (p < 0.001). For glutamate, a significant reduction was observed at 40 min compared to baseline. The results showed that there was a spontaneous increase of serotonin 2 h after the insertion of the catheter in patients with TMD. In conclusion, the results showed that there are differences in the masseter muscle levels of serotonin and glutamate during acute nociception in patients with myofascial TMD compared to healthy subjects.
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| 31. |
- Blanton, Michael R., et al.
(författare)
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Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
- 2017
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Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
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| 34. |
- Dawson, Andreas, et al.
(författare)
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ASSESSMENT OF PROPRIOCEPTIVE ALLODYNIA AFTER TOOTH CLENCHING
- 2010
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Ingår i: Abstracts of the 13th World Congress of Pain. - : IASP (International Association for the Study of Pain and Omnipress).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Eccentric muscle exercise can induce delayed onset muscle soreness (DOMS). It is known that vibratory stimulus is an effective method to stimulate mechanoreceptors and that 80-Hz vibratory stimulus increases pain in an eccentric exercised muscle (Weerakkody et al. 2001). Lund (1994) suggested that bruxism is related to DOMS. This study evaluates the effects of experimental tooth clenching on vibrotactile and pressure sensitivity in healthy females. Methods: Sixteen healthy females (mean age 32 ± 10) participated in this study, which comprised three sessions. In each session participants were randomly assigned to a tooth clenching exercise, with a clenching level of 10%, 20%, or 40% of maximal voluntary clenching (MVC). The first day of each session, patients did six bouts of tooth clenching exercises, each bout lasting 5 minutes during 1 hour. Registrations were made at baseline, after each bout of tooth clenching (short perspective), and after 24 and 48 hours. A Vibrameter®was used to measure the vibration threshold (VT). A fixed vibratory stimulus (100 Hz, 399.99-μm amplitude) was applied for 15 s and the perceived intensity of vibration (PIV) and perceived discomfort (PD) were rated on 0-50-100 scales (0 = no sensation; 50 = pain threshold/discomfort; 100 = worst imaginable pain/worst imaginable discomfort). An electronic algometer was used to measure pressure pain thresholds (PPT). A 0-10 visual analogue scale (VAS) measured pain intensity (VP) and fatigue (VF). All registrations were made on the central and most prominent part of the right masseter muscle. Results: No main effects of contraction level was observed for VT (P=0.184) or PIV (P=0.628), but there were significant time effects (P<0.001; P<0.05) with significant increases in VT at 30, 40, 50 and 60 min (Dunnett: P<0.05) and significant increase in PIV at 40 min compared to baseline (Dunnett: P<0.05). There were no main effects of contraction level (P=0.524) or time (P=0.705) for PD. For PPT there was no effect of contraction (P=0.819) but a significant time effect (P<0.01) with decreases at 50 and 60 min compared to baseline (Dunnett: P<0.05). Main effects of contraction level and time were observed for VP and VF (both P<0.001). VP and VF were significantly increased at 40% MVC, and at 10-60 min and at 24 h follow-up. Conclusions: This study demonstrated that tooth clenching alters VT only in the short term perspective. Tooth clenching at different levels is associated with moderate levels of pain and fatigue and changes in PPT. The effect on PIV and PD was small, thus suggesting that tooth clenching is not directly related to DOMS.
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| 35. |
- Dawson, Andreas, et al.
(författare)
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Assessment of proprioceptive allodynia after tooth clenching exercises
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Bruxism is suggested to be a risk factor of temporomandibular disorders and a contributing factor to delayed onset muscle soreness (DOMS). Assessments of proprioceptive allodynia—a phenomenon that occurs in muscles with DOMS—could indicate whether bruxism leads to DOMS. This study evaluated whether experimental tooth clenching leads to DOMS. Sixteen healthy females (mean age 32 ± 10 years) participated in three 60-min sessions with 15-min follow-ups at 24 and 48 h. Participants were randomly assigned tooth clenching exercises with clenching levels of 10%, 20%, or 40% of maximal voluntary clenching (MVC). A Vibrameter® measured perceived intensity of vibration (PIV) and perceived discomfort (PD), which were assessed on 0–50–100 numeric rating scales. An electronic algometer measured pressure pain thresholds (PPT). A 0–100-mm visual analogue scale measured pain intensity (VASpain) and fatigue (VASfatigue). Measurements were made on the right masseter muscle. Clenching level had no main effect on PIV and time effects (p < 0.05) were only observed at 40 min (Dunnet: p < 0.01). Clenching level and time had no effect on PD. Only time effects were significant for PPT (p < 0.01) with reductions at 50 and 60 min compared to baseline (Dunnett: p’s < 0.05). Clenching level and time had main effects for VASpain and VASfatigue (p < 0.001). We conclude that experimental tooth clenching at various levels is not related to DOMS—since no signs of proprioceptive allodynia were observed—but to a development of moderate levels of pain and fatigue and reduced PPT.
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| 36. |
- Dawson, Andreas, et al.
(författare)
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Assessment of Proprioceptive Allodynia After Tooth-Clenching Exercises
- 2012
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Ingår i: Journal of Orofacial Pain. - : Quintessence. - 1064-6655 .- 1945-3396. ; 26:1, s. 39-48
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To (A) evaluate test-retest reliability of vibrotactile sensitivity in the masseter muscle and (B) test if (1) the vibration threshold is decreased after experimental tooth clenching, (2) intense vibrations exacerbate pain after tooth clenching, (3) pain and fatigue are increased after tooth clenching, and (4) pressure pain thresholds are decreased after tooth clenching. METHODS: In part A, 25 healthy female volunteers (mean age: 42 ± 12 years) participated, and 16 healthy females (mean age 32 ± 10 years) participated in three 60-minute sessions, each with 24- and 48-hour follow-ups in part B. Participants were randomly assigned tooth-clenching exercises with clenching levels of 10%, 20%, or 40% of maximal voluntary clenching. A Vibrameter applied to the right masseter muscle measured perceived intensity of vibration and perceived discomfort, which were assessed on 0-50-100 numeric rating scales. An electronic algometer measured pressure pain threshold (PPT). Two 0- to 100-mm visual analog scales measured pain intensity (VASpain) and fatigue (VASfatigue). Measurements were made on the right masseter muscle. Interclass correlation coefficient (ICC) was used to calculate test-retest reliability of VT measurements. Outcome variables were tested with two-way ANOVAs for repeated measures and Dunnett's post-hoc test. RESULTS: Moderate long-term (ICC 0.59) and good short-term (ICC 0.92) reliability was found for VT on the masseter muscle. Clenching level had no main effect on perceived intensity of vibration; time effects (P < .05) were only observed at 40 minutes (Dunnett's test: P < .01). Clenching level and time had no effect on perceived discomfort. Only time effects were significant for PPT (P < .01), with reductions at 50 and 60 minutes compared to baseline (Dunnett's test: P < .05). Clenching level and time had main effects for VASpain and VASfatigue (P < .001). Conclusion: Experimental tooth clenching appears to evoke moderate levels of pain and fatigue and short-lasting hyperalgesia to mechanical stimulation, but not proprioceptive allodynia. The absence of proprioceptive allodynia does not necessarily exclude delayed onset muscle soreness (DOMS) but warrants further studies on the clinical manifestations of DOMS in jaw muscles.
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| 37. |
- Dawson, Andreas, et al.
(författare)
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Comparison of pain thresholds and pain tolerance levels between Middle Easterners and Swedes and between genders
- 2009
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Ingår i: Journal of Oral Rehabilitation. - : Wiley. - 1365-2842 .- 0305-182X. ; 36:4, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study evaluates the presence of culture and gender differences in pain thresholds and pain tolerance levels between Middle Easterners and Swedes. METHODS: Sixty-four healthy individuals, 32 Middle Easterners (16 men and 16 women, mean age: 24.6 +/- 3.4 years) and 32 Swedes (16 men and 16 women, mean age: 24 +/- 3.5 years) participated in the study. Three experimental pain tests were conducted in each participant. Pain thresholds and pain tolerance levels were measured using an algometer (mechanical stimulus), the PainMatcher((R)) (electric stimulus) and cold pressor test (thermal stimulus). RESULTS: While no significant differences in pain thresholds were observed between Middle Easterners and Swedes in algometer and cold pressor tests, differences in pain tolerance levels were significant (P < 0.01 for both tests). All between-culture differences in pain perception, pain threshold and pain tolerance level were non-significant when measured with the PainMatcher. Significant between-gender differences were observed only in pain threshold with the PainMatcher (P < 0.05) and in pain tolerance level with the algometer (P < 0.01) and the PainMatcher (P <0.001). CONCLUSION: This study found significant differences in two out of three pain tolerance level tests - but not pain threshold tests - between the Middle Eastern and Swedish cultures and between genders. These differences were more pronounced between Middle Eastern and Swedish men than between Middle Eastern and Swedish women. Gender differences were more pronounced within the Swedish than the Middle Eastern culture. These findings indicate that culture and gender influence pain experience.
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| 38. |
- Dawson, Andreas, et al.
(författare)
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Development of a quality-assessment tool for experimental bruxism studies : reliability and validity
- 2013
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Ingår i: Journal of Orofacial Pain. - : Quintessence. - 1064-6655 .- 1945-3396. ; 27:2, s. 111-122
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To combine empirical evidence and expert opinion in a formal consensus method in order to develop a quality-assessment tool for experimental bruxism studies in systematic reviews. METHODS: Tool development comprised five steps: (1) preliminary decisions, (2) item generation, (3) face-validity assessment, (4) reliability and discriminitive validity assessment, and (5) instrument refinement. The kappa value and phi-coefficient were calculated to assess inter-observer reliability and discriminative ability, respectively. RESULTS: Following preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was compiled. Eleven experts were invited to join a Delphi panel and 10 accepted. Four Delphi rounds reduced the preliminary tool-Quality-Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS)- to 8 items: study aim, study sample, control condition or group, study design, experimental bruxism task, statistics, interpretation of results, and conflict of interest statement. Consensus among the Delphi panelists yielded good face validity. Inter-observer reliability was acceptable (k = 0.77). Discriminative validity was excellent (phi coefficient 1.0; P < .01). During refinement, 1 item (no. 8) was removed. CONCLUSION: Qu-ATEBS, the seven-item evidence-based quality assessment tool developed here for use in systematic reviews of experimental bruxism studies, exhibits face validity, excellent discriminative validity, and acceptable inter-observer reliability. Development of quality assessment tools for many other topics in the orofacial pain literature is needed and may follow the described procedure.
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| 39. |
- Dawson, Andreas, et al.
(författare)
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Dopamine in plasma : a biomarker for myofascial TMD pain?
- 2016
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Ingår i: Journal of Headache and Pain. - : Springer. - 1129-2369 .- 1129-2377. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dopaminergic pathways could be involved in the pathophysiology of myofascial temporomandibular disorders (M-TMD). This study investigated plasma levels of dopamine and serotonin (5-HT) in patients with M-TMD and in healthy subjects. METHODS: Fifteen patients with M-TMD and 15 age- and sex-matched healthy subjects participated. The patients had received an M-TMD diagnosis according to the Research Diagnostic Criteria for TMD. Perceived mental stress, pain intensity (0-100-mm visual analogue scale), and pressure pain thresholds (PPT, kPa) over the masseter muscles were assessed; a venous blood sample was taken. RESULTS: Dopamine in plasma differed significantly between patients with M-TMD (4.98 ± 2.55 nM) and healthy controls (2.73 ± 1.24 nM; P < 0.01). No significant difference in plasma 5-HT was observed between the groups (P = 0.75). Patients reported significantly higher pain intensities (P < 0.001) and had lower PPTs (P < 0.01) compared with the healthy controls. Importantly, dopamine in plasma correlated significantly with present pain intensity (r = 0.53, n = 14, P < 0.05) and perceived mental stress (r = 0.34, n = 28, P < 0.05). CONCLUSIONS: The results suggest that peripheral dopamine might be involved in modulating peripheral pain. This finding, in addition to reports in other studies, suggests that dopaminergic pathways could be implicated in the pathophysiology of M-TMD but also in other chronic pain conditions. More research is warranted to elucidate the role of peripheral dopamine in the pathophysiology of chronic pain.
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| 41. |
- Dawson, Andreas, et al.
(författare)
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Effect of experimental tooth clenching on the release of β-endorphin
- 2014
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Ingår i: Journal of oral & facial pain and headache. - : Quintessence. - 2333-0384 .- 2333-0376. ; 28:2, s. 159-164
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To investigate the association between experimental tooth clenching and the release of β-endorphin in patients with myofascial temporomandibular disorders (M-TMD) and healthy subjects. METHODS: Fifteen M-TMD patients and 15 healthy subjects were included and assigned an experimental tooth-clenching task. Venous blood was collected and pain intensity was noted on a visual analog scale. The masseter pressure pain threshold (PPT) was assessed 2 hours before the clenching task and immediately after. A mixed-model analysis of variance was used for statistical analyses. RESULTS: Significant main effects for time and group were observed for pain intensity and PPT, with significantly lower mean values of pain intensity (P < .001) and PPT (P < .01) after the clenching task compared with baseline. M-TMD patients had significantly higher pain intensity (P < .001) and significantly lower PPT (P < .05) than healthy subjects. No significant time or group effects were observed for the level of β-endorphin. Neither pain intensity nor PPT correlated significantly with β-endorphin levels. CONCLUSION: This experimental tooth-clenching task was not associated with significant alterations in β-endorphin levels over time, but with mechanical hyperalgesia and low to moderate levels of pain in healthy subjects and M-TMD patients, respectively. More research is required to understand the role of the β-endorphinergic system in the etiology of M-TMD
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| 42. |
- Dawson, Andreas, et al.
(författare)
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Effects of Experimental Tooth Clenching on Pain and Intramuscular Release of 5-HT and Glutamate in Patients With Myofascial TMD
- 2015
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Ingår i: The Clinical Journal of Pain. - : Lippincott, Williams andamp; Wilkins. - 0749-8047 .- 1536-5409. ; 31:8, s. 740-749
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: It has been suggested that tooth clenching may be associated with local metabolic changes, and is a risk factor for myofascial temporomandibular disorders (M-TMD). This study investigated the effects of experimental tooth clenching on the levels of 5-HT, glutamate, pyruvate, and lactate, as well as on blood flow and pain intensity, in the masseter muscles of M-TMD patients. Methods: Fifteen patients with M-TMD and 15 pain-free controls participated. Intramuscular microdialysis was performed to collect 5-HT, glutamate, pyruvate, and lactate and to assess blood flow. Two hours after the insertion of a microdialysis catheter, participants performed a 20-minute repetitive tooth clenching task (50% of maximal voluntary contraction). Pain intensity was measured throughout. Results: A significant effect of group (P less than 0.01), but not of time, was observed on 5-HT levels and blood flow. No significant effects of time or group occurred on glutamate, pyruvate, or lactate levels. Time and group had significant main effects on pain intensity (P less than 0.05 and less than 0.001). No significant correlations were identified between: (1) 5-HT, glutamate, and pain intensity; or between (2) pyruvate, lactate, and blood flow. Discussion: This experimental tooth clenching model increased jaw muscle pain levels in M-TMD patients and evoked low levels of jaw muscle pain in controls. M-TMD patients had significantly higher levels of 5-HT than controls and significantly lower blood flow. These 2 factors may facilitate the release of other algesic substances that may cause pain.
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| 43. |
- Dawson, Andreas
(författare)
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Experimental tooth clenching : a model for studying mechanisms of muscle pain
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- “I felt like I’d done three rounds with Mike Tyson…all becauseI was grinding my teeth in my sleep”, så beskrev en patient somintervjuades av Daily Mail i en artikel där det ökade problemet medöverbelastning i käkarna beskrevs, vilket kan leda till tandslitage,muskelsmärta, och frakturer på tandmaterial. Det personliga lidandet,och de ekonomiska kostnaderna för både individ och samhälle ärstort. Bruxism innebär en daglig och/eller nattlig tandpressningeller tandgnissling och anges med en förekomst av ca 10-20% ibefolkningen.Tidigare undersökningar har visat att tandpressning ochpsykologisk stress är vanligare bland patienter med kroniskmuskelsmärta i ansiktet jämfört med friska försökspersoner, ochanses kunna bidra till kronisk muskelsmärta i ansiktet, så kalladmyofasciell temporomandibulär dysfunktion (M-TMD). Dethar även föreslagits att bruxism, t ex tandpressning, kan leda tillträningsvärk i tuggmuskulaturen. M-TMD är ett smärttillstånd somkan drabba tuggmuskulaturen och är ungefär dubbelt så vanligt hoskvinnor som hos män. Vanligt förekommande symtom är smärtaoch ömhet i tuggmuskulaturen, men även en reducerad tuggfunktion.Flera studier har använt sig av experimentellatandpressningsmodeller för att öka förståelsen mellan tandpressningoch smärta i tuggmuskulaturen. I dessa studier har olika stor bitkraftanvänts vid tandpressningen, vilket resulterar i att det blir svårt attjämföra resultaten från dessa studier och dra slutsatser om vilkatandpressningsmodeller som är de mest optimala.12Vid tandpressning så kan det bli syrefattigt i tuggmuskulaturen,vilket kan resultera i en frisättning av smärtframkallande substanser,såsom serotonin och glutamat. I tuggmuskulaturen finns detsmärtreceptorer som kan aktiveras av dessa substanser. I tidigarestudier har man observerat att patienter med M-TMD har en högrehalt av dessa substanser i tuggmuskulaturen jämfört med friskaindivider.Finns det ett samband mellan tandpressning och träningsvärk?Hur kommer det sig att patienter med M-TMD har en högre haltav serotonin och glutamat i tuggmuskulaturen? Denna kunskapsaknas idag, således var det övergripande målet med denna avhandlingatt öka kunskapen om detta. På sikt kan denna kunskap bidra tillförbättrade diagnostiska metoder, och behandlingsmodeller.I studie I så utvecklades ett instrument som undersöker kvalitetenpå experimentella bruxismstudier, som senare kan användas i ensystematisk översikt, så att slutsatser kan dras avseende de mestoptimala experimentella bruxism modellerna som inducerar ensmärta på friska individer som efterliknar den kliniska smärtan sompatienter med M-TMD uppvisar.I studie II undersöktes sambandet mellan tandpressning vidolika bitkraftsnivåer och träningsvärk. Våra resultat antyder attträningsvärk i tuggmuskulaturen inte tycks uppstå efter experimentelltandpressning hos friska individer.I delstudier III och IV undersöktes frisättning av serotonin ochglutamat efter tandpressning hos friska individer och patienter medM-TMD med hjälp av mikrodialys. De huvudsakliga fynden var attvi kunde bekräfta tidigare fynd, att patienter med M-TMD har enhögre halt av serotonin i tuggmuskulaturen. Däremot utsöndradesdessa substanser inte i samband med tandpressning, varken hosfriska individer eller hos patienter.
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| 44. |
- Dawson, Andreas
(författare)
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Käkmuskelsmärta : mekanismer och effekt av behandling
- 2010
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Ingår i: Tandläkartidningen. - 0039-6982. ; :3, s. 58-59
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Kronisk käkmuskelsmärta, så kallad myofasciell temporomandibulär dysfunktion (m-tmd), kännetecknas av smärta vid tuggning, begränsad tuggfunktion och gapsvårigheter. Den leder ofta till nedsatt daglig funktion och minskad livskvalitet. Förekomsten i befolkningen är ungefär tio procent och man har funnit att det är vanligare bland kvinnor än män [1]. I dag saknas det kunskap om de underliggande mekanismerna till kronisk muskelsmärta, likaså varför det är vanligare bland kvinnor. Syftet med projektet är att få ökad kunskap om de mekanismer som bidrar till muskelsmärtan, samt att i en randomiserad studie utvärdera den smärtlindrande effekten av beteendeterapi. Hypotesen som ligger till grund för forskningsprojektet är att tandpressning orsakar en frisättning av serotonin i tuggmuskulaturen, som både bidrar till och underhåller m-tmd. Denna perifera frisättning påverkas av både östrogen och kortisol. Om hypotesen stämmer bör specifik terapi inriktad på att minska överbelastning i tuggsystemet leda till att halten av intramuskulärt serotonin reduceras och därigenom också smärtlindring.
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| 45. |
- Dawson, Andreas, et al.
(författare)
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Pain and intramuscular release of algesic substances in the masseter muscle after experimental tooth-clenching exercises in healthy subjects
- 2013
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Ingår i: Journal of Orofacial Pain. - : Quintessence Publishing. - 1064-6655 .- 1945-3396 .- 2333-0384. ; 27:4, s. 350-360
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Tidskriftsartikel (refereegranskat)abstract
- AIMS:To investigate whether experimental tooth clenching leads to a release of algesic substances in the masseter muscle.METHODS:Thirty healthy subjects (16 females, 14 males) participated. During two sessions, separated by at least 1 week, intramuscular microdialysis was performed to collect masseter muscle 5-hydroxytryptamine (5-HT) and glutamate as well as the metabolic markers pyruvate and lactate. Two hours after the start of microdialysis, participants were randomized to a 20-min repetitive experimental tooth-clenching task (50% of maximal voluntary contraction) or a control session (no clenching). Pain and fatigue were measured throughout. The Friedman and Wilcoxon tests were used for statistical analyses.RESULTS:No alterations were observed in the concentrations of 5-HT, glutamate, pyruvate, and lactate over time in the clenching or control session, or between sessions at various time points. Pain (P < .01) and fatigue (P < .01) increased significantly over time in the clenching session and were significantly higher after clenching than in the control session (P < .01).CONCLUSION:Low levels of pain and fatigue developed with this experimental tooth-clenching model, but they were not associated with an altered release of 5-HT, glutamate, lactate, or pyruvate. More research is required to elucidate the peripheral release of algesic substances in response to tooth clenching.
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| 46. |
- Hidalgo-Crespo, José, et al.
(författare)
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An exploratory study for product-as-a-service (PaaS) offers development for electrical and electronic equipment
- 2024
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Ingår i: Procedia CIRP. - 2212-8271. ; 122, s. 521-526
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Tidskriftsartikel (refereegranskat)abstract
- Manufacturing enterprises continue to grapple with transforming from their existing business model, which revolves around designing and selling tangible products, to business models centered on providing a blend of products and services. Product-as-a-Service (PaaS) emerges as a business strategy capable of catalyzing the shift toward higher levels of circularity. However, effecting changes in operational methodologies and value delivery mechanisms is imperative, consequently prompting modifications in the core business strategies of these companies. The objective of this study is to discern and categorize prevailing PaaS business models for electrical and electronic equipment (EEE). The Business Model Canvas (BMC) is introduced as a foundational tool to facilitate this transition, emphasizing the central role of the value proposition within the business model. Additionally, the study underscores the importance of robust take-back systems and repairability in PaaS implementation, particularly within the EEE sector. It highlights the need for novel partnerships, redesigned reverse logistics networks, and efficient product assessment methods to facilitate environmentally responsible decisions. Furthermore, the research evaluates the financial implications of PaaS adoption through Life Cycle Costing (LCC), emphasizing its value in predicting and addressing temporary financial complications, thereby ensuring a smoother transition to service-oriented business models.
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| 47. |
- Hudson, Lawrence N, et al.
(författare)
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The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project
- 2017
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 7:1, s. 145-188
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Tidskriftsartikel (refereegranskat)abstract
- The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
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| 48. |
- Ikoma, Tomoko, et al.
(författare)
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Effects of Low-Intensity Contractions of Different Craniofacial Muscles in Healthy Participants : An Experimental Cross-Over Study
- 2018
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Ingår i: Headache. - : John Wiley & Sons. - 0017-8748 .- 1526-4610. ; 58:4, s. 559-569
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Tidskriftsartikel (refereegranskat)abstract
- Objective.-Repetitive jaw-muscle activity characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible, ie, bruxism, is traditionally linked to pain and unpleasantness in the active muscles. The aim of this study was to investigate the effects of standardized craniofacial muscle contractions on self-reported symptoms. Methods.-Sixteen healthy volunteers performed six 5-minute bouts of 20% maximal voluntary contraction task of the jaw-closing (Jaw), the orbicularis-oris (O-oris), and the orbicularis-oculi (O-oculi) muscles. Participants rated their perceived pain, unpleasantness, fatigue, and mental stress levels before, during, and after the contraction tasks on 0-10 Numeric Rating Scales (NRS). Each muscle contraction task (= 1 session) was separated by at least 1 week and the order of the sessions was randomized in each subject. Results.-All muscle contraction tasks evoked significant increases in NRS scores of pain (mean +/- SD: Jaw; 3.8 +/- 2.7, O-oris; 1.9 +/- 2.2, O-oculi; 1.4 +/- 1.3, P < .014), unpleasantness (Jaw; 4.1 +/- 2.5, O-oris; 2.1 +/- 1.9, O-oculi; 2.9 +/- 1.8, P<.001), fatigue (Jaw; 5.8 +/- 2.0, O-oris; 3.2 +/- 2.3, O-oculi; 3.6 +/- 1.9, P<.001), and mental stress (Jaw; 4.1 +/- 2.1, O-oris; 2.2 +/- 2.7, O-oculi; 2.9 +/- 2.2, P<.001). The Jaw contractions were associated with higher NRS scores compared with the O-oris and the O-oculi contractions (P<.005) without differences between the O-oris and the O-oculi (P>.063). All symptoms disappeared within 1 day (P>.469). Conclusions.-The results showed that submaximal static contractions of different craniofacial muscle groups could evoke transient, mild to moderate levels of muscle pain and fatigue and increased stress scores. The fatigue resistance may differ between different muscle groups. Further studies are warranted to better understand the contribution of specific craniofacial muscle groups for the characteristic presentation of musculoskeletal pain conditions in the head.
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| 49. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 50. |
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