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  • 1.
    Bäckryd, Emmanuel
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Do low levels of Beta-endorphin in the cerebrospinal fluid indicate defective top-down inhibition in patients with chronic neuropathic pain? A cross-sectional, comparative study2014In: Pain medicine (Malden, Mass.), ISSN 1526-2375, E-ISSN 1526-4637, Vol. 15, no 1, p. 111-119Article in journal (Refereed)
    Abstract [en]

    Objective

    Pain medicine still lacks mechanism-specific biomarkers to guide diagnosis and treatment, and defective top-down modulation is an important factor in the pathophysiology of chronic pain conditions. Using modern analytical tools and advanced multivariate statistical analysis, the aim of this study was to revisit two classical potential biomarkers of pro- and anti-nociception in humans (substance P and beta-endorphin), focusing particularly on the cerebrospinal fluid (CSF).

    Design

    Cross-sectional, comparative, observational study.

    Subjects

    Patients with chronic, post-traumatic and/or post-surgical, neuropathic pain refractory to conventional treatment (N = 15) and healthy controls (N = 19) were included.

    Methods

    Samples were taken from CSF and blood, and levels of substance P and beta-endorphin were investigated using a Luminex technology kit.

    Results

    We found low levels of beta-endorphin in the CSF of neuropathic pain patients (66 ± 11 pcg/mL) compared with healthy controls (115 ± 14 pcg/mL) (P = 0.017). Substance P levels in the CSF did not differ (20 ± 2 pcg/mL, 26 ± 2, P = 0.08). However, our multivariate data analysis showed that belonging to the patient group was associated with low levels of both substances in the CSF. A higher correlation between the levels of beta-endorphin and substance P in CSF was found in healthy controls than in patients (rs = 0.725, P < 0.001 vs rs = 0.574, P = 0.032).

    Conclusions

    Patients with chronic neuropathic pain due to trauma or surgery had low levels of beta-endorphin in the CSF. We speculate that this could indicate a defective top-down modulation of pain in chronic neuropathic pain. Our results also illustrate the importance of taking a system-wide, multivariate approach when searching for biomarkers.

  • 2.
    Ernberg, M.
    et al.
    Karolinska Institutet, Huddinge, Sweden.
    Castrillon, E.E.
    Aarhus University, Denmark.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    List, T.
    Malmö University, Sweden.
    Svensson, P.
    Aarhus University and Aarhus University Hospital, Denmark.
    Experimental myalgia induced by repeated infusion of acidicsaline into the human masseter muscle does not cause the release of algesic substances2013In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 17, no 4, p. 539-550Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Animal studies have shown that two repeated intramuscular injections of acidic saline induce mechanical allodynia that lasts for 4 weeks with spread to the contralateral side. In this study, we tested the hypothesis that two repeated intramuscular infusions of acidic saline into the human masseter muscle is associated with pain, mechanical allodynia and release of algesic substances. Eighteen healthy volunteers participated. On day 1, 2.5 mL of acidic saline (pH 3.3) was infused into one of the masseter muscles and isotonic saline (pH 6.0) into the other (randomized and single-blind). Two days later, intramuscular microdialysis was performed to sample serotonin, glutamate, pyruvate, lactate and glucose, during which the saline infusions were repeated. Pain and pressure pain thresholds (PPTs) were recorded before and after infusions on both days.

    RESULTS:

    Pain intensity induced by the infusions was higher after acidic than that after isotonic saline (p < 0.05). PPTs were decreased on both sides after microdialysis compared with baseline day 1 (p's < 0.05), but there were no differences in PPTs between sides at any time point. The levels of serotonin, glutamate, pyruvate, lactate or glucose did not change significantly during microdialysis.

    CONCLUSION:

    Infusion of acidic saline caused low levels of muscle pain, but no mechanical allodynia and no increased release of algesic substances. The value of this model appears modest, but future studies could be performed with larger sample size and higher flow rate before definite conclusions about the validity of the model for craniofacial myalgia can be drawn.

  • 3.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ernberg, Malin
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Mannerkorpi, Kaisa
    Section of Physiotherapy, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden / University of Gothenburg Centre for Person-Centred Care (GPCC), Sahlgrenska Academy, Gothenburg, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, Eva
    Department of Clinical Neuroscience and Osher Centre for Integrative Medicine, Karolinska Institute, Stockholm, Sweden.
    Christidis, Nikolaos
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Increased Interstitial Concentrations of Glutamate and Pyruvate in Vastus Lateralis of Women with Fibromyalgia Syndrome Are Normalized after an Exercise Intervention: a Case-Control Study2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 10, p. 14article id e0162010Article in journal (Refereed)
    Abstract [en]

    Background Fibromyalgia syndrome (FMS) is associated with central alterations, but controversies exist regarding the presence and role of peripheral factors. Microdialysis (MD) can be used in vivo to study muscle alterations in FMS. Furthermore for chronic pain conditions such as FMS, the mechanisms for the positive effects of exercise are unclear. This study investigates the interstitial concentrations of algesics and metabolites in the vastus lateralis muscle of 29 women with FMS and 28 healthy women before and after an exercise intervention. Methods All the participants went through a clinical examination and completed a questionnaire. In addition, their pressure pain thresholds (PPTs) in their upper and lower extremities were determined. For both groups, MD was conducted in the vastus lateralis muscle before and after a 15-week exercise intervention of mainly resistance training of the lower limbs. Muscle blood flow and interstitial muscle concentrations of lactate, pyruvate, glutamate, glucose, and glycerol were determined. Results FMS was associated with significantly increased interstitial concentrations of glutamate, pyruvate, and lactate. After the exercise intervention, the FMS group exhibited significant decreases in pain intensity and in mean interstitial concentrations of glutamate, pyruvate, and glucose. The decrease in pain intensity in FMS correlated significantly with the decreases in pyruvate and glucose. In addition, the FMS group increased their strength and endurance. Conclusion This study supports the suggestion that peripheral metabolic and algesic muscle alterations are present in FMS patients and that these alterations contribute to pain. After an exercise intervention, alterations normalized, pain intensity decreased (but not abolished), and strength and endurance improved, all findings that suggest the effects of exercise are partially peripheral.

  • 4.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Hilgenfeldt, Ulrich
    University of Heidelberg.
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Kristiansen, Jesper
    National Research Centre for the Working Environment.
    Sogaard, Karen
    National Research Centre for the Working Environment.
    Rosendal, Lars
    Cyncron A/S.
    Bradykinin and kallidin levels in the trapezius muscle in patients with work-related trapezius myalgia, in patients with whiplash associated pain, and in healthy controls - A microdialysis study of women2008In: PAIN, ISSN 0304-3959, Vol. 139, no 3, p. 578-587Article in journal (Refereed)
    Abstract [en]

    The origins of chronic Muscle pain development and maintenance are debated regarding the relative contributions of peripheral nociception and central pain processing. Bradykinin (BKN) and kallidin (KAL) have been suggested to be algesic kinins involved in muscle pain. This in vivo study investigates whether there were significant differences in interstitial muscle concentrations of BKN and KAL between chronic work-related trapezius myalgia (TM), chronic whiplash associated disorders (WAD), and healthy controls (CON). These subjects were studied Lit rest, during a 20-min repetitive low-force exercise and recovery. The interstitial concentrations of BKN and KAL of trapezius were determined using the microdialysis technique. The interstitial concentration of KAL was overall significantly higher in TM than in CON. [KAL] and [BKN] increased significantly during the brief exercise in all groups. The increase in [BKN] during exercise was significantly higher in TM than in the other two groups,whereas the increase in [KAL] during exercise was highest in WAD. In chronic pain, positive correlations existed between the two kinins and the difference in pain intensity between recovery and baseline. In this in vivo study of two groups of patients with chronic pain clinically involving the trapezius muscle, we found alterations - most prominent in TM in the interstitial concentrations of BKN and KAL. The results indicated that the two kinins were involved in aspects of hyperalgesia.

  • 5.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kristiansen, Jesper
    National Research Centre Working Environm, Denmark.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Saltin, Bengt
    University of Copenhagen, Denmark.
    Sogaard, Karen
    University of Southern Denmark, Denmark.
    Sjogaard, Gisela
    University of Southern Denmark, Denmark.
    Algogenic substances and metabolic status in work-related Trapezius Myalgia: a multivariate explorative study2014In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 15, no 357Article in journal (Refereed)
    Abstract [en]

    Background: This study compares the levels of algesic substances between subjects with trapezius myalgia (TM) and healthy controls (CON) and explores the multivariate correlation pattern between these substances, pain, and metabolic status together with relative blood flow changes reported in our previous paper (Eur J Appl Physiol 108: 657-669, 2010). Methods: 43 female workers with (TM) and 19 females without (CON) trapezius myalgia were - using microdialysis - compared for differences in interstitial concentrations of interleukin-6 (IL-6), bradykinin (BKN), serotonin (5-HT), lactate dehydrogenas (LDH), substance P, and N-terminal propeptide of procollagen type I (PINP) in the trapezius muscle at rest and during repetitive/stressful work. These data were also used in multivariate analyses together with previously presented data (Eur J Appl Physiol 108: 657-669, 2010): trapezius muscle blood flow, metabolite accumulation, oxygenation, and pain development and sensitivity. Results: Substance P was significantly elevated in TM (p=0.0068). No significant differences were found in the classical algesic substances (p: 0.432-0.926). The multivariate analysis showed that blood flow related variables, interstitial concentrations of metabolic (pyruvate), and algesic (BKN and K+) substances were important for the discrimination of the subjects to one of the two groups (R-2: 0.19-0.31, pless than0.05). Pain intensity was positively associated with levels of 5-HT and K+ and negatively associated with oxygenation indicators and IL-6 in TM (R-2: 0.24, pless than0.05). A negative correlation existed in TM between mechanical pain sensitivity of trapezius and BKN and IL-6 (R-2: 0.26-0.39, pless than0.05). Conclusion: The present study increased understanding alterations in the myalgic muscle. When considering the system-wide aspects, increased concentrations of lactate, pyruvate and K+ and decreased oxygenation characterized TM compared to CON. There are three major possible explanations for this finding: the workers with pain had relatively low severity of myalgia, metabolic alterations preceded detectable alterations in levels of algesics, or peripheral sensitization and other muscle alterations existed in TM. Only SP of the investigated algesic substances was elevated in TM. Several of the algesics were of importance for the levels of pain intensity and mechanical pain sensitivity in TM. These results indicate peripheral contribution to maintenance of central nociceptive and pain mechanisms and may be important to consider when designing treatments.

  • 6.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Potential Muscle Biomarkers of Chronic Myalgia in Humans - A Systematic Review of Microdialysis Studies2012In: Biomarker / [ed] Tapan Kumar Khan, INTECH, 2012, p. 102-132Chapter in book (Other academic)
    Abstract [en]

    The impact of biomarkers in present day health care system, health management and healthy life is enormous. Clinicians need them for diagnosis, prognosis, effect of therapeutic intervention, and most importantly, for early detection of a disease. Pharmaceutical industries need them for new drug discovery and drug efficiency test. Regulatory authorities need them for testing toxicity and environmental impact. Epidemiologists need them for population screening and risk factor determination. In post genomic era biomarkers would have a huge impact in personalized medicine and personalized health management. This scope of this book is not limited to just a few of the most important aspects of biomarkers but covers wide variety of subjects, from biomarkers cancer to neurodegenerative diseases. Chapters cover variety of aspects, from modern cell based technologies to molecular imaging; from drug discovery to critical care prognosis. A great amount of information is also devoted to bioinformatics and statistics. There is an enormous potential for commercial value of biomarkers. The global diagnostic market accounts for only 1-2% of government healthcare expense, however, it influences on 60-70% decisions in healthcare. My sincere thanks go to all the contributors of this book who took the extra effort beyond their busy schedules. Last, but not least I would like to express my gratitude to the publishing group for their tireless support

  • 7.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Forsberg, Frida
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stensson, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Chronic Widespread Pain: Increased Glutamate and Lactate Concentrations in the Trapezius Muscle and Plasma2014In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 30, no 5, p. 409-420Article, review/survey (Refereed)
    Abstract [en]

    BACKGROUND:: Chronic widespread pain (CWP), including fibromyalgia syndrome (FM), is associated with prominent negative consequences. CWP has been associated with alterations in the central processing of nociception. Whereas some researchers consider CWP/FM as a central hyperexcitability pain condition, others suggest that the central alterations are maintained by peripheral nociceptive input. Microdialysis can be used in vivo to study muscle alterations in chronic myalgia. AIM:: The aim of the study was to investigate the plasma and interstitial concentrations of metabolites and algesics in the trapezius muscle of women with CWP and in pain-free women (CON).

    MATERIALS AND METHODS:: Seventeen women with CWP and 24 CON went through a clinical examination and completed a questionnaire; the pressure pain thresholds in the upper and lower extremities were registered. Microdialysis was conducted in the trapezius muscle, and a blood sample was drawn. Muscle blood flow, interstitial muscle concentrations, and plasma concentrations of lactate, pyruvate, glutamate, glucose, and glycerol (not in the plasma) were determined.

    RESULTS:: CWP patients had significantly increased interstitial muscle (P=0.02 to 0.001) and plasma (P=0.026 to 0.017) concentrations of lactate and glutamate. No significant differences existed in blood flow between CWP and CON. The interstitial concentrations-but not the plasma levels-of glutamate and lactate correlated significantly with aspects of pain such as pressure pain thresholds of the trapezius (R=0.22) and tibialis anterior (R=0.18) and the mean pain intensity (R=0.10) in CWP but not in CON.

    CONCLUSIONS:: The present study supports the suggestion that aspects of pain and central alterations in CWP/FM are influenced by peripheral tissue alterations.

  • 8.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Lemming, Dag
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Kristiansen, Jesper
    Cyncron A/S.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Peolsson, Michael
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Rosendal, Lars
    National Research Centre for the Working Environment.
    Biochemical alterations in the trapezius muscle of patients with chronic whiplash associated disorders (WAD): A microdialysis study2008In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 12, no 1, p. 82-93Article in journal (Refereed)
    Abstract [en]

    The mechanisms behind the development of chronic trapezius myalgia in patients with whiplash associated disorders (WAD) appear to involve both peripheral and central components, but the specific contribution of alterations in muscle is not clear. Female patients with WAD and involvement of trapezius (N = 22) and female controls (N = 20; CON) were studied during an experiment compromised of rest (baseline), 20 min repetitive low-force exercise and 120 min recovery. Their interstitial concentrations of serotonin (5-HT), glutamate, lactate, pyruvate, potassium, interleukin-6 (IL-6), and blood flow were determined in the trapezius muscle using a microdialysis technique. Pressure pain thresholds (PPT) over trapezius and tibialis anterior muscles were also assessed. In WAD, we found signs of generalized hypersensitivity according to PPT. The WAD group had significantly higher interstitial [IL-6] and [5-HT] in the trapezius than the CON. [Pyruvate] was overall significantly lower in WAD, and with lactate it showed another time-pattern throughout the test. In the multivariate regression analysis of pain intensity [5-HT] was the strongest regressor and positively correlated with pain intensity in WAD. In addition, blood flow, [pyruvate], and [potassium] influenced the pain intensity in a complex time dependent way. These findings may indicate that peripheral nociceptive processes are activated in WAD with generalized hypersensitivity for pressure and they are not identical with those reported in chronic work-related trapezius myalgia, which could indicate different pain mechanisms.

  • 9.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Soderberg, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine .
    Salvador Puigvert, Laia
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Rosendal, Lars
    TrialConsult, Gentofte, Denmark.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    INCREASED INTERSTITIAL CONCENTRATIONS OF PYRUVATE AND LACTATE IN THE TRAPEZIUS MUSCLE OF PATIENTS WITH FIBROMYALGIA: A MICRODIALYSIS STUDY2010In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 42, no 7, p. 679-687Article in journal (Refereed)
    Abstract [en]

    Objective: The aim of this study was to compare the interstitial concentrations of pyruvate, lactate and glutamate in the trapezius muscle between patients with fibromyalgia syndrome and healthy controls. Design: Comparative cross-sectional study. Subjects: Patients with fibromyalgia (n=19) and healthy controls (n=19); all women. Methods: Subjects answered a questionnaire about different aspects of pain. Pressure pain thresholds over the trapezius and tibialis anterior muscles were determined. The interstitial concentrations of pyruvate, lactate and glutamate were determined in the resting trapezius muscle by the microdialysis technique, with samples collected every hour for 5 consecutive hours. Pain intensity was also rated. Results: Significantly higher interstitial concentrations of pyruvate and lactate were found in patients with fibromyalgia syndrome. The multivariate regression analyses of group membership and pressure pain thresholds of the trapezius confirmed the importance of pyruvate and lactate. Conclusion: Different mechanisms that may increase pyruvate and lactate in patients with fibromyalgia syndrome are discussed. Improved understanding of peripheral muscle alterations in patients with fibromyalgia syndrome could lead to mechanism-based rehabilitation.

  • 10.
    Ghafouri, Bijar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Sjörs, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Leandersson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Interstitial concentration of serotonin is increased in myalgic human trapezius muscle during rest, repetitive work and mental stress - an in vivo microdialysis study2010In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 70, no 7, p. 478-486Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The pathophysiology of trapezius myalgia is not fully elucidated. Serotonin (5-HT) is involved in modulation of nociception and hyperalgesia. Our aim was to compare the interstitial 5-HT levels of the trapezius muscle in women with chronic trapezius myalgia and in pain-free controls.

    MATERIALS AND METHODS: Microdialysate of the trapezius muscle collected every 20 minutes during rest, work (100 min) and stress (20 min) was used to study the dynamics of 5-HT in women with chronic trapezius myalgia (MYA; n=18) and in pain-free controls (CON; n=30).

    RESULTS: MYA had higher levels of 5-HT than CON at baseline, during repetitive work, during mental stress and during recovery. There were no significant time effects on 5-HT levels.

    CONCLUSION: 5-HT has the potential of a biomarker of chronic myalgia. Elevated levels of 5-HT may be involved in maintenance of habitual chronic pain and might contribute to increased pain during exercise by facilitating the effect of released algesic substances linked to such muscle demands.

  • 11.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Umeå University, Umeå, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Fowler, Christopher J.
    Umeå University, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Effects of Two Different Specific Neck Exercise Interventions on Palmitoylethanolamide and Stearoylethanolamide Concentrations in the Interstitium of the Trapezius Muscle in Women with Chronic Neck Shoulder Pain2014In: Pain medicine (Malden, Mass.), ISSN 1526-2375, E-ISSN 1526-4637, Vol. 15, no 8, p. 1379-1389Article in journal (Refereed)
    Abstract [en]

    Purpose. Chronic neck/shoulder pain (CNSP) is one of the most common pain conditions. The understanding of mechanisms, including the peripheral balance between nociceptive and antinociceptive processes, is incomplete. N-acylethanolamines (NAEs) are a class of endogenous compounds that regulate inflammation and pain. The aim of this study was to investigate the levels of two NAEs: the peroxisome proliferator-activated receptor type-a ligand palmitoylethanolamide (PEA) and stearoylethanolamide (SEA) in the muscle interstitium of the trapezius muscle in women with CNSP randomized to two different neck specific training programs and in a healthy pain-free control group (CON). Materials and Methods. Fifty-seven women with CNSP were randomized to strength + stretch or stretch alone exercise programs. Twenty-nine subjects underwent microdialysis procedure before and after 4-6 months of exercise. Twenty-four CON subjects underwent microdialysis procedure before and after 4-6 months without any intervention in between. Microdialysate samples were collected from the trapezius muscle and analyzed by mass spectrometry for PEA and SEA levels. Results. PEA and SEA levels were significantly higher in CNSP patients compared with CON. PEA was significantly higher in CNSP than in CON after both training programs. SEA was significantly higher in CNSP than in CON after stretch alone but not after strength + stretch training. A significant positive correlation was found between changes in pain intensity and in SEA levels in the strength + stretch group, but not in the stretch alone group. Conclusion. Our results indicate that exercise interventions differentially affect the levels of the bioactive lipids PEA and SEA in the interstitium of the trapezius muscle in women with CNSP.

  • 12.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stensson, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Fowler, Christopher J.
    Umeå University, Sweden .
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Palmitoylethanolamide and stearoylethanolamide levels in the interstitium of the trapezius muscle of women with chronic widespread pain and chronic neck-shoulder pain correlate with pain intensity and sensitivity2013In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 154, no 9, p. 1649-1658Article in journal (Refereed)
    Abstract [en]

    Chronic widespread pain (CWP) is a complex condition characterized by central hyperexcitability and altered descending control of nociception. However, nociceptive input from deep tissues is suggested to be an important drive. N-Acylethanolamines (NAEs) are endogenous lipid mediators involved in regulation of inflammation and pain. Previously we have reported elevated levels of the 2 NAEs, the peroxisome proliferator-activated receptor type-alpha ligand N-palmitoylethanolamine (PEA) and N-stearoylethanolamine (SEA) in chronic neck/shoulder pain (CNSP). In the present study, the levels of PEA and SEA in women with CWP (n = 18), CNSP (n = 34) and healthy controls (CON, n = 24) were investigated. All subjects went through clinical examination, pressure pain threshold measurements and induction of experimental pain in the tibialis anterior muscle. Microdialysis dialysate of the trapezius was collected before and after subjects performed a repetitive low-force exercise and analyzed by mass spectrometry. The levels of PEA and SEA in CNSP were significantly higher post exercise compared with CWP, and both pre and post exercise compared with CON. Levels of both NAEs decreased significantly pre to post exercise in CWP. Intercorrelations existed between aspects of pain intensity and sensitivity and the level of the 2 NAEs in CWP and CNSP. This is the first study demonstrating that CNSP and CWP differ in levels of NAEs in response to a low-force exercise which induces pain. Increases in pain intensity as a consequence of low-force exercise were associated with low levels of PEA and SEA in CNSP and CWP. These results indicate that PEA and SEA have antinociceptive roles in humans.

  • 13.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Fowler, Christopher J.
    Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    High Levels of N-Palmitoylethanolamide and N-Stearoylethanolamide in Microdialysate Samples from Myalgic Trapezius Muscle in Women2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 11Article in journal (Refereed)
    Abstract [en]

    Background: N-acylethanolamines (NAEs) are endogenous compounds that regulate inflammation and pain. These include the cannabinoid ligand anandamide (AEA) and the peroxisome proliferator-activated receptor-a ligand palmitoylethanolamide (PEA). Little is known as to the levels of NAEs in pain states in human, particularly in the skeletal muscle. The aim of this study was to investigate the levels of these lipid mediators in muscle dialysate from women with chronic neck-/shoulder pain compared to healthy controls. Methods: Eleven women with chronic neck-/shoulder pain and eleven healthy women participated in this study. All participants went through microdialysis procedures in the trapezius muscle. Muscle dialysate samples were collected during four hours and analysed by nano liquid chromatography tandem mass spectrometry (nLC-MS/MS). Results: We were able to detect AEA, PEA, N-stearoylethanolamine (SEA) and 2-arachidonoylglycerol (2-AG) in a single chromatographic run. Of the NAEs studied, PEA and SEA were clearly detectable in the muscle microdialysate samples. The muscle dialysate levels of PEA and SEA were significantly higher in myalgic subjects compared to healthy controls. Conclusion: This study demonstrates that microdialysis in combination with mass spectrometry can be used for analysing NAEs in human muscle tissue regularly over time. Furthermore the significant group differences in the concentration of PEA and SEA in this study might fill an important gap in our knowledge of mechanisms in chronic myalgia in humans. In the long run this expanded understanding of nociceptive and anitinociceptive processes in the muscle may provide a base for ameliorating treatment and rehabilitation of pain.

  • 14.
    Grimby-Ekman, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. University of Gothenburg, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Bjork, Jonas
    Lund University, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Comorbidities, intensity, frequency and duration of pain, daily functioning and health care seeking in local, regional, and widespread pain-a descriptive population-based survey (SwePain)2015In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 16, no 165Article in journal (Refereed)
    Abstract [en]

    Background: The clinical knowledge of factors related to the spread of pain on the body has increased and understanding these factors is essential for effective pain treatment. This population-based study examines local (LP), regional (RP), and widespread pain (WSP) on the body regarding comorbidities, pain aspects, and impact of pain and elucidates how the spread of pain varies over time. Material and methods: A postal questionnaire that addressed pain aspects (intensity, frequency, duration and anatomical spreading on a body manikin), comorbidities and implications of pain (i.e., work situation, physical activity, consumption of health care and experience of hospitality and treatment of health care) was sent to 9000 adults living in southeastern Sweden. Of these, 4774 (53 %) completed and returned the questionnaire. After 9 weeks, a follow-up questionnaire was sent to the 2983 participants who reported pain in the first questionnaire (i.e. 62 % of 4774 subjects). Of these, 1940 completed and returned the questionnaire (i.e. 65 % of 2983 subjects). The follow-up questionnaire included the same items as the first questionnaire. Results: This study found differences in intensity, frequency and duration of pain, comorbidities, aspects of daily functioning and health care seeking in three pain categories based on spreading of pain: LP, RP and WSP. Compared to the participants with RP and LP, the participants with WSP had lower education and worse overall health, including more frequent heart disease and hypertension. In addition, participants with WSP had more intense, frequent, and long-standing pain, required more medical consultations, and experienced more impact on work. The participants with RP constituted an intermediate group regarding frequency and intensity of pain, and impact on work. The participants with LP were the least affected group regarding these factors. A substantial transition to RP had occurred by the 9-week follow-up. Conclusions: This study shows an association between increased spread of pain and prevalence of heart disease, hypertension, more severe pain characteristics (i.e., intensity, frequency and duration), problems with common daily activities and increased health care seeking. The WSP group was the most affected group and the LP group was the least affected group. Regarding these factors, RP was an obvious intermediate group. The transitions between the pain categories warrant research that broadly investigates factors that increase and decrease pain.

  • 15.
    Hadrevi, J
    et al.
    Umeå University, Sweden .
    Ghafouri, Bijar
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center. Linköping University, Department of Medical and Health Sciences, Division of Community Medicine.
    Sjörs, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Antti, H
    Umeå University, Sweden .
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Crenshaw, A G.
    University of Gavle, Sweden .
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Hellstrom, F
    University of Gavle, Sweden .
    Comparative metabolomics of muscle interstitium fluid in human trapezius myalgia: an in vivo microdialysis study2013In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 113, no 12, p. 2977-2989Article in journal (Refereed)
    Abstract [en]

    The mechanisms behind trapezius myalgia are unclear. Many hypotheses have been presented suggesting an altered metabolism in the muscle. Here, muscle microdialysate from healthy and myalgic muscle is analysed using metabolomics. Metabolomics analyse a vast number of metabolites, enabling a comprehensive explorative screening of the cellular processes in the muscle. less thanbrgreater than less thanbrgreater thanMicrodialysate samples were obtained from the shoulder muscle of healthy and myalgic subjects that performed a work and stress test. Samples from the baseline period and from the recovery period were analysed using gas chromatography-mass spectrometry (GC-MS) together with multivariate analysis to detect differences in extracellular content of metabolites between groups. Systematic differences in metabolites between groups were identified using multivariate analysis and orthogonal partial least square discriminate analysis (OPLS-DA). A complementary Mann-Whitney U test of group difference in individual metabolites was also performed. less thanbrgreater than less thanbrgreater thanA large number of metabolites were detected and identified in this screening study. At baseline, no systematic differences between groups were observed according to the OPLS-DA. However, two metabolites, l-leucine and pyroglutamic acid, were significantly more abundant in the myalgic muscle compared to the healthy muscle. In the recovery period, systematic difference in metabolites between the groups was observed according to the OPLS-DA. The groups differed in amino acids, fatty acids and carbohydrates. Myristic acid and putrescine were significantly more abundant and beta-d-glucopyranose was significantly less abundant in the myalgic muscle. less thanbrgreater than less thanbrgreater thanThis study provides important information regarding the metabolite content, thereby presenting new clues regarding the pathophysiology of the myalgic muscle.

  • 16.
    Hadrevi, Jenny
    et al.
    Umeå University, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Hellstrom, Fredrik
    University of Gävle, Sweden.
    Multivariate Modeling of Proteins Related to Trapezius Myalgia, a Comparative Study of Female Cleaners with or without Pain2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 9Article in journal (Refereed)
    Abstract [en]

    The prevalence of chronic trapezius myalgia is high in women with high exposure to awkward working positions, repetitive movements and movements with high precision demands. The mechanisms behind chronic trapezius myalgia are not fully understood. The purpose of this study was to explore the differences in protein content between healthy and myalgic trapezius muscle using proteomics. Muscle biopsies from 12 female cleaners with work-related trapezius myalgia and 12 pain free female cleaners were obtained from the descending part of the trapezius. Proteins were separated with two-dimensional differential gel electrophoresis (2D-DIGE) and selected proteins were identified with mass spectrometry. In order to discriminate the two groups, quantified proteins were fitted to a multivariate analysis: partial least square discriminate analysis. The model separated 28 unique proteins which were related to glycolysis, the tricaboxylic acid cycle, to the contractile apparatus, the cytoskeleton and to acute response proteins. The results suggest altered metabolism, a higher abundance of proteins related to inflammation in myalgic cleaners compared to healthy, and a possible alteration of the contractile apparatus. This explorative proteomic screening of proteins related to chronic pain in the trapezius muscle provides new important aspects of the pathophysiology behind chronic trapezius myalgia.

  • 17.
    Hadrévi, Jenny
    et al.
    Umeå University, Sweden.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Carlsson, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Linköping University, Faculty of Medicine and Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Hellström, Fredrik
    University of Gävle, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Myosin light chain and calcium regulating protein differences in chronic musculoskeletal neck and shoulder pain2016In: Journal of Integrated OMICS, ISSN 2182-0287, Vol. 6, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Proteomic screening analysis has detected myosin light chain (MLC) as a protein implied to be involved in chronic musculoskeletal neck and shoulder pain. Several analyses of MLC proteins have stated a difference in phosphorylation being the determining factor for protein activation hence altered contrability of the muscle in i.e. senescence. In continuation of a previous publication, this study is an attempt to analyze the different MLC isoforms by mass spectrometry and immune-analyses in myalgic and healthy trapezius muscle. In the present study no differences in phosphorylation level between the corresponding individual proteins were detected using LC-MSMS and immunoblotting; instead we assigned different isoforms of regulatory MLCs. To further elucidate the contrability: calcium (Ca2+) regulatory proteins, sarco(endo)plasmic reticulum Ca2+ ATPase 1 (SERCA-1) and calsequestrine (CSQ) were analyzed by western blot. The analysis revealed a significantly increased abundance of SERCA-1 protein in the myalgic muscle and a significantly increased abundance of CSQ in healthy muscle. Myalgic muscle contraction patterns have in previous studies shown to differ from healthy muscle which may be connected to the Ca2+ availability in the muscle. Here we present the proteomic characterization of differences in Ca2+ regulating proteins and particularly regulatory MLCs in trapezius muscle of women with chronic musculoskeletal neck and shoulder pain.

  • 18.
    Järemo, Pirjo
    et al.
    Division of Nursing, Department of Neurobiology, Care Sciences and Society, Karolinska University, Huddinge, Sweden.
    Arman, M.
    Division of Nursing, Department of Neurobiology, Care Sciences and Society, Karolinska University, Huddinge, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gottberg, K.
    Division of Nursing, Department of Neurobiology, Care Sciences and Society, Karolinska University, Huddinge, Sweden.
    Illness beliefs among patients with chronic widespread pain - associations with self-reported health status, anxiety and depressive symptoms and impact of pain2017In: BMC Psychology, E-ISSN 2050-7283, Vol. 5, no 24Article in journal (Refereed)
    Abstract [en]

    Chronic widespread pain (CWP) is a disabling condition associated with a decrease in health. Illness beliefs are individual and are acquired during life. Constraining beliefs may prevent patients from regaining health. Understanding these patients’ illness beliefs may be a way to improve the health care they are offered. The aim of this study was to describe illness beliefs among patients with CWP and associations with self-reported health, anxiety and depressive symptoms, and impact of pain.

  • 19.
    Jöud, Anna
    et al.
    Division of Occupational and Environmental Medicine, Department of Laboratory Medicine Lund, Lund University, Lund, Sweden.
    Björk, Jonas
    Division of Occupational and Environmental Medicine, Department of Laboratory Medicine Lund, Lund University, Lund, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Grimby-Ekman, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Health Metrics, University of Gothenburg, Gothenburg, Sweden..
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    The association between pain characteristics, pain catastrophizing and health care use: Baseline results from the SWEPAIN cohort2017In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 16, p. 122-128, article id S1877-8860(17)30122-2Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND AIM: Pain is common and adds to the global burden of disease. However, individuals suffering from pain are a heterogeneous group in terms of pain spreading, intensity and duration. While pain influences overall health care consultation not everyone with pain consult health care. To be able to provide health care matching the patients' needs increased knowledge about what factors determines the decision to consult health care is essential. The aim of this study was to explore the combined importance of pain spreading, intensity, duration and pain catastrophizing for consulting health care.

    METHODS: In this cross-sectional study we used population based survey data from southeast Sweden (SWEPAIN) including 7792 individuals' aged 16-85 reporting pain. We used Modified Poisson regressions to analyse factors of importance related to the decision to consult health care.

    RESULTS: High and moderate pain intensity, as compared to low, increases the probability of consulting health care (High PR=1.7 [95% CI 1.51-1.88], moderate PR=1.2 [1.15-1.41]). Having widespread pain, as compared to localised pain, increased the probability of consulting health (PR=1.2 [1.03-1.36). Pain duration was not associated with increased probability of consulting health care (PR=1.0 CI0.88-1.07). However an interaction (p=0.05) between pain duration and pain catastrophizing beliefs was seen indicating a combined importance of the two when consulting health care.

    CONCLUSION: Our result suggests that pain intensity, pain spreading and pain catastrophizing independently influence the decision to consult health care while there is an interaction effect between pain duration and pain catastrophizing beliefs where the importance of pain catastrophizing believes differ with pain duration; the importance of pain catastrophizing believes differ with pain duration.

    IMPLICATIONS: Treatment and rehabilitation strategies should incorporate this finding in order to meet the individual's needs focusing on the biopsychosocial model within health care focusing not only on actual pain reliefs but also on for example acceptance and behavioural changes.

  • 20.
    Karlson, Bjorn
    et al.
    Lund University.
    Jonsson, Peter
    Lund University.
    Palsson, Birgitta
    Lund University.
    Abjornsson, Gunnel
    Lund University.
    Malmberg, Birgitta
    Lund University.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Osterberg, Kai
    Lund University.
    Return to work after work after a workplace-oriented intervention for patients on sick-leave for burnout - a prospective controlled study2010In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 10Article in journal (Refereed)
    Abstract [en]

    Background: In the present study the effect of a workplace-oriented intervention for persons on long-term sick leave for clinical burnout, aimed at facilitating return to work (RTW) by job-person match through patient-supervisor communication, was evaluated. We hypothesised that the intervention group would show a more successful RTW than a control group. Methods: In a prospective controlled study, subjects were identified by the regional social insurance office 2-6 months after the first day on sick leave. The intervention group (n = 74) was compared to a control group who had declined participation, being matched by length of sick leave (n = 74). The RTW was followed up, using sick-listing register data, until 1.5 years after the time of intervention. Results: There was a linear increase of RTW in the intervention group during the 1.5-year follow-up period, and 89% of subjects had returned to work to some extent at the end of the follow-up period. The increase in RTW in the control group came to a halt after six months, and only 73% had returned to work to some extent at the end of the 1.5-year follow-up. Conclusions: We conclude that the present study demonstrated an improvement of long-term RTW after a workplace-oriented intervention for patients on long-term sick leave due to burnout. Trial registration: Current Controlled Trials NCT01039168.

  • 21.
    Karlsson, Linn
    et al.
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Region Östergötland, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Bäckryd, Emmanuel
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Olausson, Patrik
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Intramuscular pain modulatory substances before and after exercise in women with chronic neck pain2015In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 19, no 8, p. 1075-1085Article in journal (Refereed)
    Abstract [en]

    BackgroundIn peripheral tissue, several substances influence pain and pain modulation. Exercise has been found to decrease pain and improve function for chronic pain conditions, but how and why exercise produces beneficial effects remains unclear. This study investigates whether aspects of pain and concentrations of substances with algesic, analgesic and metabolic functions differ between women with chronic neck shoulder pain (CNSP) and healthy women (CON) and whether changes are found after an exercise intervention for CNSP. MethodsForty-one women with CNSP and 24 CON subjects were included. The participants attended two microdialysis sessions with 4-6 months between the experiments. During this period, the CNSP subjects underwent an exercise intervention. Expression levels of substance P, beta-endorphin, cortisol, glutamate, lactate and pyruvate as well as pain intensity and pressure pain thresholds were analysed. ResultsAt baseline, higher concentrations of glutamate and beta-endorphin and lower concentrations of cortisol in CNSP than CON were found. After exercise, decreased levels of substance P and possibly of glutamate, increased levels of beta-endorphin and cortisol as well as decreased pain intensity and increased pain pressure thresholds were found for CNSP. ConclusionsThe findings at baseline indicated algesic and analgesic alterations in the painful trapezius muscles. The findings for CNSP after the exercise intervention, with changes in peripheral substances and decreased pain intensity and sensitivity, could reflect a long-term physiological effect of the exercise.

  • 22.
    Karlsson, Linn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Takala, Esa-Pekka
    Finnish Institute Occupat Heatlh, Finland .
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Evaluation of pain and function after two home exercise programs in a clinical trial on women with chronic neck pain - with special emphasises on completers and responders2014In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 15, no 6Article in journal (Refereed)
    Abstract [en]

    Background: Different types of exercises can help manage chronic neck pain. Supervised exercise interventions are widely used, but these protocols require substantial resources. The aim of this trial, which focused on adherence, was to evaluate two home exercise interventions. Methods: This parallel group randomized controlled trial included 57 women randomly allocated into two groups - a strength training group (STRENGTH, 34 subjects) and a stretching group (STRETCH, 23 subjects). The interventions focused on the neck and shoulder muscles and lasted for 12 months. The STRENGTH group performed weight training and ended each session with stretching exercises. These stretching exercises constituted the entirety of the STRETCH groups training session. Both groups were instructed to exercise three times per week. All the participants kept an exercise diary. In addition, all participants were offered support via phone and e-mail. The primary outcomes were pain intensity and function. The trial included a four-to six-month and a twelve-month follow-up. A completer in this study exercised at least 1,5 times per week during eight unbroken weeks. A responder in this study reported clinically significant improvements on pain and function. The statistical analyses used the Mann Whitney U-test, Wilcoxon signed-rank test, and X-2 test. Results: At four-to six-months, the numbers of completers were 19 in the STRENGTH group and 17 in the STRETCH group. At twelve months, the corresponding numbers were 11 (STRENGTH) and 10 (STRETCH). At four-to six-months, the proportions of subjects reporting clinically important changes (STRENGTH and STRETCH) were for neck pain: 47% and 41%, shoulder pain: 47% and 47%, function: 37% and 29%. At twelve months, the corresponding numbers were for neck pain: 45% and 40%, shoulder pain: 55% and 50%, function: 55% and 20%. Conclusions: No differences in the two primary outcomes between the two interventions were found, a finding that may be due to the insufficient statistical power of the study. Both interventions based on home exercises improved the two primary outcomes, but the adherences were relatively low. Future studies should investigate ways to improve adherence to home exercise treatments.

  • 23.
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Arbetsrelaterade senfäste-nerv- och muskelsmärtor2006In: Rehabiliteringsmedicin: Teori och Praktik / [ed] Jörgen Borg, Lund: Studenlitteratur , 2006, 1, p. 149-155Chapter in book (Other academic)
    Abstract [sv]

    Kapitel om rehabiliteringsmedicinens utveckling och nuvarande plats i sjukvården samt begrepp och metodik inleder boken. I två delar ges därefter rehabiliteringsmedicinska aspekter på de dominerande sjukdomsgrupperna - komplexa smärttillstånd respektive skador och sjukdomar i nervsystemet. Som avslutning beskrivs bland annat  stressrelaterade tillstånd. Läroboken är avsedd för grundutbildning av läkare, arbetsterapeuter och sjukgymnaster, logopeder samt för läkare under AT-tjänstgöring. Den är också lämplig som introduktion i specialistutbildningen i rehabiliteringsmedicin, geriatrik, neurologi och smärtlindring. Vidareutbildningar av olika vårdyrkesgrupper kan ha nytta av boken och den kan också användas som referenslitteratur av yrkesverksamma med intresse för rehabiliteringsmedicin

  • 24.
    Larsson, Britt
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Balogh, Istvan
    Is there a relationship between fibromyalgia syndrome and work conditions?2005In: Journal of Musculoskeletal Pain, ISSN 1058-2452, E-ISSN 1540-7012, Vol. 13, no 4Article in journal (Refereed)
    Abstract [en]

    Objectives: This study examines the initial course of the fibromyalgia syndrome [FMS] and the influence of physical and psychosocial workplace factors on developing FMS. Methods: Patients with FMS were recruited to participate in a structured interview about pain and physical and psychosocial load. In addition, they participated in a clinical examination. Physical load in occupational life was assessed by two validated indices relevant for risk evaluation of pain in the upper extremities and the neck. Results: Of the 116 female FMS patients [25-45 years] recruited, 64 agreed to participate. Seventy percent of the participants noted that their pain started out as localized pain. The neck [52 percent], the shoulders [45 percent], and the low back [28 percent] were the regions most frequently engaged. The localized pain worsened to widespread pain [median six years after start of pain]. For the 71 percent of the participants who were working at the onset of pain, the onset occurred after eight occupationally active years. They scored relatively high on the validated measures of physical load for the employment period, including the time for onset of pain. To a higher degree, the FMS patients had heavy and light repetitive work compared to the age-matched women from the same geographic area. The odds ratio affected by FMS when occupied in heavy or light repetitive work was 5.1 [95 percent CI: 3.4-7.7] compared to subjects occupied in administration, computer work, or medium heavy variable work-tasks. Conclusions: Job strain and strenuous events were more common in the FMS group than in the control group. The majority of FMS patients had been exposed to a substantially risky physical work-load. Hence, we consider physical workload as an important risk factor for localized pain and for FMS. Occurrence of job strain probably enhances the risk for the development of FMS. The frequently reported strenuous events might have contributed to spreading localized pain. © 2005 by The Haworth Press, Inc. All rights reserved.

  • 25.
    Larsson, Britt
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Karlsson, Jan-Eric
    Yrkesmedicin Lunds universitet.
    Nielsen, Jörn
    Yrkesmedicin Lunds universitet.
    Respiratory and ocular symptoms in workers exposed to potassium aluminium-tetrafluoride soldering flux2007In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 80, no 7, p. 627-633Article in journal (Refereed)
    Abstract [en]

    Background: Exposure to aluminium compounds, such as fluorides in gaseous and particulate form, places people who work in potrooms at risk for respiratory symptoms. Workers in potrooms, however, also are exposed to a number of other air contaminants. In this study, we present the first report of a dose-response relationship after exposure to potassium aluminium tetrafluoride (KAlF4) and the influence of smoking and atopy. Materials: All workers (308) from an industrial plant that used KAlF as soldering flux were invited to participate in the study. In all, 289 workers participated and 118 employees not exposed to chemicals in their professional work served as an unexposed group. Methods: In the first step, all subjects answered a questionnaire concerning respiratory symptoms and work history, and participated in a lung function examination. In a second step, all workers who reported work-related complaints from lower respiratory airways were invited to participate in medical examination, methacholine test, screening test of respiratory allergy, and skin prick test against KAlF4. Results: The exposed subjects had more symptoms than the unexposed group, dry cough odds ratio (OR): 5.17 (confidence interval 1.79-15.0), stuffy nose: 2.3 (1.25-4.22), nose bleeding: 10.7 (3.26-35.3) and ocular symptoms 5.01 (1.92-13.1) except for chest tightening and wheezing, and shortness of breath. The symptoms appeared in a dose response-like manner although the ORs between high and low exposed were significant for only chest tightening and wheezing, 2.62 (1.30-5.26) and stuffy nose 2.1 (1.22-3.66). Smokers and atopics did not report more frequent work-related symptoms. Smokers were significantly less hyperreactive than non-smokers, indicating a healthy-worker effect. No one showed a positive skin prick test against KAlF4. Conclusion: In spite of exposure levels of KAlF4well below the new Swedish threshold limit, value frequent respiratory and ocular symptoms were reported. No evidence of IgE mediated allergy was found. © Springer-Verlag 2007.

  • 26.
    Larsson, Britt
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Rosendal, L
    DanTrials AS, Denmark.
    Kristiansen, J
    Denmark.
    Sjogaard, G
    Denmark.
    Sogaard, K
    Denmark.
    Ghafouri, Bijar
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Abdiu, Avni
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Kjaer, M
    Bispebjerg Hospital.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Responses of algesic and metabolic substances to 8 h of repetitive manual work in myalgic human trapezius muscle2008In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 140, no 3, p. 479-490Article in journal (Refereed)
    Abstract [en]

    The trapezius muscle often develops pain as the result of repetitive and stressful work tasks although it is unclear to what extent this pain is due to alterations in muscle concentrations of algesic/nociceptive substances. Twenty women with chronic neck- and shoulder pain (TM) whose work required highly repetitive work tasks and 20 pain-free female colleagues (CON) were studied during and after a full 8-hour workday. We collected microdialysates from their dominant/most painful trapezius muscle; concentrations of serotonin, glutamate, lactate, pyruvate, potassium, bradykinin, and cytokines and blood flow were determined. In addition, we measured surface electromyogram, task exposure level, pain intensity, perceived mental stress, and urine-cortisol. In connection to the clinical neck and Shoulder examination, we determined pressure pain thresholds (PPTs) over the trapezius and tibialis muscles. TM had higher concentrations Of glutamate (71 +/- 42 vs. 36 +/- 15 mu mol l(-1)) and pyruvate (187 +/- 89 vs. 125 +/- 63 mu mol l(-1)) than CON. Interstitial serotonin was higher ill TM (before work: 10.6 +/- 10.8 vs. 2.2 +/- 1.2 nM; after work: 9.2 +/- 8.3 vs. 1.5 +/- 2.9 nM). The trapezius blood flow during the working day was higher in TM than in CON. TM had lower PPT and higher pain intensity throughout the working day. No differences in EMG, task exposure level, Mental Stress, Or Urine-cortisol in the groups were found. These findings Support the idea that peripheral nociceptive processes are activated ill Occupationally active Subjects, who are diagnosed with trapezius myalgia. In contrast, no sign of low blood flow or increased stress or muscle activity markers were found in TM.

  • 27.
    Larsson, Britt
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Sögaard, Karen
    National Research Centre for Working Environment, Copenhagen, Denmark.
    Rosendahl, Lars
    Department of Clinical Operations Birkeröd, Denmark.
    Work related neck-shoulder pain: a review on magnitude, risk factors, biochemical characteristics, clinical picture and preventive interventions2007In: Baillière's Best Practice & Research: Clinical Rheumatology, ISSN 1521-6942, E-ISSN 1532-1770, Vol. 21, no 3, p. 447-463Article in journal (Refereed)
    Abstract [en]

    The purpose of this review is to scrutinize the physiology of neck-shoulder pain and trapezius myalgia based on the most recent scientific literature. Therefore, systematic literature searches have been conducted. Occurrence of neck-shoulder pain, risk factors for development of neck-shoulder pain, and its work-relatedness are addressed. Furthermore, the latest information on the biochemical milieu within healthy and painful neck-shoulder muscles is reviewed. Finally diagnosis of and intervention for neck and shoulder pain are discussed. © 2007 Elsevier Ltd. All rights reserved.

  • 28.
    Olausson, Patrik
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Relative recovery over time – an in vivo microdialysisstudy of human skeletal muscle2013In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 73, no 1, p. 10-16Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    The microdialysis technique is a method for sampling endogenous molecules from the interstitial compartments of varying tissues and relies on diffusion of molecules between the tissue and a perfusate via a membrane. Such samples do not allow determination of the true interstitial concentration but only a certain percentage. This gives rise to one of the most crucial parameter that needs to be considered for a dependable microdialysis; the relative recovery. Relative recovery states the efficiency of which an analyte is extracted from its external medium. Aim. To investigate the relative recovery of small molecules (< 20 kDa) such as lactate, fluid recovery and the reproducibility of the relative recovery at group and individual level of the microdialysis technique applied in muscle.

    MATERIALS AND METHODS:

    Using in vivo microdialysis of the trapezius muscle of 65 women from two separate occasions 4-6 months apart. Relative recovery of small molecules was measured from samples collected every 20 min during a period of 220 min.

    RESULTS:

    Good reproducibility at group level of catheters with cut-offs 100 and 20kDa were found. Furthermore, there was a high and steady relative recovery with an overall good fluid recovery. Poor reproducibility was found at the individual level for both catheters.

    CONCLUSIONS:

    This study demonstrates that when using microdialysis in skeletal muscle relative recovery is stable over time and is not affected by low-force exercise. Although there is a good reproducibility at group level this is not the case at the individual level. Thus in vivo, the relative recovery should be determined for each test subject and at each test occasion.

  • 29.
    Olausson, Patrik
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Linköping University, Department of Medical and Health Sciences, Division of Community Medicine.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Identification of Proteins from Interstitium of Trapezius Muscle in Women with Chronic Myalgia Using Microdialysis in Combination with Proteomics2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 12Article in journal (Refereed)
    Abstract [en]

    Background: Microdialysis (MD) of the trapezius muscle has been an attractive technique to investigating small molecules and metabolites in chronic musculoskeletal pain in human. Large biomolecules such as proteins also cross the dialysis membrane of the catheters. In this study we have applied in vivo MD in combination with two dimensional gel electrophoresis (2-DE) and mass spectrometry to identify proteins in the extracellular fluid of the trapezius muscle. Materials and Methods: Dialysate from women with chronic trapezius myalgia (TM; n = 37), women with chronic wide spread pain (CWP; n = 18) and healthy controls (CON; n = 22) was collected from the trapezius muscle using a catheter with a cut-off point of 100 kDa. Proteins were separated by two-dimensional gel electrophoresis and visualized by silver staining. Detected proteins were identified by nano liquid chromatography in combination with tandem mass spectrometry. Results: Ninety-seven protein spots were identified from the interstitial fluid of the trapezius muscle; 48 proteins in TM and 30 proteins in CWP had concentrations at least two-fold higher or lower than in CON. The identified proteins pertain to several functional classes, e.g., proteins involved in inflammatory responses. Several of the identified proteins are known to be involved in processes of pain such as: creatine kinase, nerve growth factor, carbonic anhydrase, myoglobin, fatty acid binding protein and actin aortic smooth muscle. Conclusions: In this study, by using in vivo microdialysis in combination with proteomics a large number of proteins in muscle interstitium have been identified. Several of the identified proteins were at least two-fold higher or lower in chronic pain patients. The applied techniques open up for the possibility of investigating protein changes associated with nociceptive processes of chronic myalgia. © 2012 Olausson et al.

  • 30.
    Palstam, Annie
    et al.
    Gothenburg University, Sweden; University of Gothenburg Centre Person Centre Care GPCC, Sweden.
    Larsson, Anette
    Gothenburg University, Sweden; University of Gothenburg Centre Person Centre Care GPCC, Sweden.
    Bjersing, Jan
    Gothenburg University, Sweden.
    Lofgren, Monika
    Karolinska Institute, Sweden.
    Ernberg, Malin
    Karolinska Institute, Sweden.
    Bileviciute-Ljungar, Lndre
    Karolinska Institute, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Sjörs, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, Eva
    Karolinska Institute, Sweden; Karolinska Institute, Sweden.
    Mannerkorpi, Kaisa
    Gothenburg University, Sweden; University of Gothenburg Centre Person Centre Care GPCC, Sweden .
    PERCEIVED EXERTION AT WORK IN WOMEN WITH FIBROMYALGIA: EXPLANATORY FACTORS AND COMPARISON WITH HEALTHY WOMEN2014In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 46, no 8, p. 773-780Article in journal (Refereed)
    Abstract [en]

    Objective: To investigate perceived exertion at work in women with fibromyalgia. Design: A controlled cross-sectional multi-centre study. Subjects and methods: Seventy-three women with fibromyalgia and 73 healthy women matched by occupation and physical workload were compared in terms of perceived exertion at work (0-14), muscle strength, 6-min walk test, symptoms rated by Fibromyalgia Impact Questionnaire (FIQ), work status (25-100%), fear avoidance work beliefs (0-42), physical activity at work (7-21) and physical workload (1-5). Spearmans correlation coefficient and linear regression analysis were conducted. Results: Perceived exertion at work was significantly higher in the fibromyalgia group than in the reference group (p=0.002), while physical activity at work did not differ between the groups. Physical capacity was lower and symptom severity higher in fibromyalgia compared with references (pless than0.05). In fibromyalgia, perceived exertion at work showed moderate correlation with physical activity at work, physical workload and fear avoidance work beliefs (r(s) = 0.53 0.65, pless than0.001) and a fair correlation with anxiety (r(s) = 0.26, p=0.027). Regression analysis indicated that the physical activity at work and fear avoidance work beliefs explained 50% of the perceived exertion at work. Conclusion: Women with fibromyalgia perceive an elevated exertion at work, which is associated with physical work-related factors and factors related to fear and anxiety.

  • 31.
    Peolsson, Michael
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine .
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Brodin, L.-A.
    School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    A pilot study using tissue velocity ultrasound imaging (TVI) to assess muscle activity pattern in patients with chronic trapezius myalgia2008In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 9, no 127Article in journal (Refereed)
    Abstract [en]

    Background. Different research techniques indicate alterations in muscle tissue and in neuromuscular control of aching muscles in patients with chronic localized pain. Ultrasound can be used for analysis of muscle tissue dynamics in clinical practice. Aim. This study introduces a new muscle tissue sensitive ultrasound technique in order to provide a new methodology for providing a description of local muscle changes. This method is applied to investigate trapezius muscle tissue response - especially with respect to specific regional deformation and deformation rates - during concentric shoulder elevation in patients with chronic trapezius myalgia and healthy controls before and after pain provocation. Methods. Patients with trapezius myalgia and healthy controls were analyzed using an ultrasound system equipped with tissue velocity imaging (TVI). The patients performed a standardized 3-cm concentric shoulder elevation before and after pain provocation/exercise at a standardized elevation tempo (30 bpm). A standardized region of interest (ROI), an ellipsis with a size that captures the upper and lower fascia of the trapezius muscle (4 cm width) at rest, was placed in the first frame of the loop registration of the elevation. The ROI was re-anchored frame by frame following the same anatomical landmark in the basal fascia during all frames of the concentric phase. In cardiac measurement, tissue velocities are measured in the axial projection towards and against the probe where red colour represents shortening and red lengthening. In the case of measuring the trapezius muscle, tissue deformation measurements are made orthogonally, thus, indirectly. Based on the assumption of muscle volume incompressibility, blue represents tissue contraction and red relaxation. Within the ROI, two variables were calculated as a function of time: deformation and deformation rate. Hereafter, max, mean, and quadratic mean values (RMS) of each variable were calculated and compared before and after pain provocation/ exercise. Results. This new methodology seems valuable when looking at local muscle changes and studying the mechanism behind chronic muscle pain. The univariate analyses indicate that patients with chronic trapezius myalgia after pain provocation due to exercise at group level showed decreased strain and unchanged strain rate while healthy controls had unchanged strain and increased strain rate. However, the multivariate analysis indicates that most patients showed lower levels according to both strain and strain rate after exercise compared to most controls. Conclusion. Tissue velocity imaging can help describe musculoskeletal tissue activity and dynamics in patients with chronic pain conditions. An altered muscle tissue dynamic after pain provocation/exercise among the majority of trapezius myalgia patients compared with the healthy controls was found. © 2008 Peolsson et al, licensee BioMed Central Ltd.

  • 32.
    Persson, Ann L
    et al.
    Umeå University.
    Sjolund, Bengt H
    Umeå University.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Three Clusters of Different Properties Characterize Women with Chronic Trapezius Myalgia2008In: Journal of Musculoskeletal Pain, ISSN 1058-2452, E-ISSN 1540-7012, Vol. 16, no 4, p. 287-297Article in journal (Refereed)
    Abstract [en]

    Objectives: A correlative study on data from 14 women with unilateral chronic shoulder pain was undertaken.

    Methods: Data were obtained on evoked pain and pressure pain thresholds [PPTs] changes upon muscle exertion and biopsy findings on capillary density and Muscular pathology. The PPTs were measured in the trapezius muscle, before and after a static abduction endurance test of the shoulder [electronic algometer]. Holding time and pain intensity was registered. Capillarization and ragged red fibers, cytochrome-c-oxidase negative fibers, and moth-eaten muscle fibers were analyzed in the same trapezius muscles.

    Results: Principal component analysis was used for multivariate analysis, showing a model with three statistically significant components. The first component explained 33 percent of the variation. Pressure pain threshold changes were positively correlated with capillarization, and negatively correlated with prevalence of moth-eaten fibers and cytochrome-c-oxidase negative fibers. The second component explained 23 percent of the variation, and reflected the correlations between holding time, differences in pain and PPTs, i.e., between various aspects of perceived pain after exertion. The third component explained 19 percent of the variation. The pain difference correlated positively with the prevalence of cytochrome-c-oxidase negative fibers and raggedred fibers; subjects with high prevalence of these two fiber types presented increased pain. In summary, Our results suggest that not only capillarization and histopathological findings of the trapezius muscle, but also centrally modulated pain intensity and PPT changes after muscle exertion are associated.

    Conclusions: Three clusters of different properties were revealed in women with trapezius myalgia, highlighting the multifactorial mechanisms responsible. These components may have prognostic value.

  • 33.
    Persson, Roger
    et al.
    National Research Centre of Working Environment, Denmark.
    Helene Garde, Anne
    National Research Centre of Working Environment, Denmark.
    Marie Hansen, Ase
    National Research Centre of Working Environment, Denmark.
    Osterberg, Kai
    Lund University.
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Orbaek, Palle
    National Research Centre of Working Environment, Denmark.
    Karlson, Bjorn
    Lund University.
    Seasonal Variation in Human Salivary Cortisol Concentration2008In: Chronobiology International, ISSN 0742-0528, E-ISSN 1525-6073, Vol. 25, no 6, p. 923-937Article in journal (Refereed)
    Abstract [en]

    Measurement of cortisol concentration can contribute important information about an individuals ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month-to-month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30min, +8h, and at 21:00h. Data were analyzed by a repeated measures design with month (12 levels) and time-of-day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p0.4). The main effects of month and time-of-day were statistically significant (p0.001). Highest concentrations were observed in February, March, and April, and lowest concentrations were observed in July and August. There were no statistically significant effects in any of the other measures, or between men and women. In conclusion, a seasonal variation in salivary cortisol concentrations was detected in an occupationally active population. Thus, seasonal variation needs to be taken into account when designing and evaluating field studies and interventions and when making comparisons across studies.

  • 34.
    Peterson, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Carlfjord, Siw
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Schaller, Anne
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Using education and support strategies to improve the way nurses assess regular and transient pain: A quality improvement study of three hospitals2017In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 16, no 1, p. 15-21Article in journal (Refereed)
    Abstract [en]

    Background and aims

    Systematic and regular pain assessment has been shown to improve pain management. Well-functioning pain assessments require using strategies informed by well-established theory. This study evaluates documented pain assessments reported in medical records and by patients, including reassessment using a Numeric Rating Scale (NRS) after patients receive rescue medication.

    Methods

    Documentation surveys (DS) and patient surveys (PS) were performed at baseline (BL), after six months, and after 12 months in 44 in-patient wards at the three hospitals in Östergötland County, Sweden. Nurses and nurse assistants received training on pain assessment and support. The Knowledge to Action Framework guided the implementation of new routines.

    Results

    According to DS pain assessment using NRS, pain assessment increased significantly: from 7% at baseline to 36% at 12 months (p < 0.001). For PS, corresponding numbers were 33% and 50% (p < 0.001). According to the PS, the proportion of patients who received rescue medication and who had been reassessed increased from 73% to 86% (p = 0.003). The use of NRS to document pain assessment after patients received rescue medication increased significantly (4% vs. 17%; p < 0.001).

    Conclusions

    After implementing education and support strategies, systematic pain assessment increased, an encouraging finding considering the complex contexts of in-patient facilities. However, the achieved assessment levels and especially reassessments related to rescue medication were clinically unsatisfactory. Future studies should include nursing staff and physicians and increase interactivity such as providing online education support. A discrepancy between documented and reported reassessment in association with given rescue medication might indicate that nurses need better ways to provide pain relief.

    Implications

    The fairly low level of patient-reported pain via NRS and documented use of NRS before and 12 months after the educational programme stresses the need for education on pain management in nursing education. Implementations differing from traditional educational attempts such as interactive implementations might complement educational programmes given at the work place. Standardized routines for pain management that include the possibility for nurses to deliver pain medication within well-defined margins might improve pain management and increase the use of pain assessments. Further research is needed that examines the large discrepancy between patient-reported pain management and documentation in the medical recording system of transient pain.

  • 35.
    Rosendal, Lars
    et al.
    Arbetsmiljöinstitutet, Köpenhamn, Danmark.
    Kristiansen, Jesper
    Arbetsmiljöinstitutet, Köpenhamn, Danmark.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Sögaard, Karen
    Arbetsmiljöinstitutet, Köpenhamn, Danmark.
    Peolsson, Michael
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine.
    Kjaer, Michael
    Bispebjerg sjukhus, Köpenhamn, Danmark.
    Sörensen, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia2005In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 119, no 1-3, p. 201-209Article in journal (Refereed)
    Abstract [en]

    The mechanisms behind the development of work-related trapezius pain are suggested to involve both peripheral and central components, but the specific contribution of alterations in muscle nociceptive and other substances is not clear. Female patients with chronic trapezius myalgia (N=19, TM) and female controls (N=20, CON) were studied at rest, during 20 min repetitive low-force exercise and recovery, and had their interstitial concentrations of potassium (K+), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and collagen turnover determined in the trapezius muscle by the microdialysis technique. K+ levels were at all time points higher in TM than in CON (P<0.0001). Baseline levels of LDH and IL-6 were similar in both groups. In response to exercise pain intensity, rated perceived exertion, and the concentrations of K+, LDH and IL-6 increased significantly in both groups. [K+] immediately decreased to baseline levels in CON but remained elevated during the first 20 min of recovery in TM (P<0.01) whereafter it returned to baseline level. In all subjects taken together mean [K+] correlated negatively with pressure pain threshold of trapezius (P<0.001), positively with mean pain intensity VAS (P<0.001) and mean perceived exertion (P<0.001). Rises in muscle LDH and IL-6 as well as the anabolic ratio for collagen type I was not significantly different between groups. In conclusion, patients with chronic pain in the trapezius muscle had increased levels of interstitial potassium. This finding could be causally related to myalgia or secondary to pain due to deconditioned muscle or altered muscle activity pattern. © 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  • 36.
    Sandberg, Margareta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden.
    Lindberg, Lars-Göran
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Different patterns of blood flow response in the trapezius muscle following needle stimulation (acupuncture) between healthy subjects and patients with fibromyalgia and work-related trapezius myalgia2005In: European Journal of Pain, ISSN 1090-3801, Vol. 9, no 5, p. 497-510Article in journal (Refereed)
    Abstract [en]

    Needle stimulation (acupuncture) has recently been shown to increase blood flow in the tibialis anterior muscle and overlying skin in healthy subjects (HS) and patients with fibromyalgia (FM). The aim of the present study was to examine the effect of needle stimulation on local blood flow in the trapezius muscle and overlying skin in HS and two groups of patients suffering from chronic pain in the trapezius muscle, i.e., FM and work-related trapezius myalgia (TM) patients. Two modes of needling, deep muscle stimulation (Deep) and subcutaneous needle insertion (SC), were performed at the upper part of the shoulder and blood flow was monitored for 60 min post-stimulation. Blood flow changes were measured non-invasively by using a new application of photoplethysmography. Increased blood flow in the trapezius muscle and overlying skin was found in all three groups following both Deep and SC. In HS, Deep was superior to SC in increasing skin and muscle blood flow, whereas in FM, SC was as effective as, or even more effective, than Deep. In the severely affected TM patients, no differences were found between the stimuli, and generally, a lesser blood flow response to the stimuli was found. At Deep, the muscle blood flow increase was significantly larger in HS, compared to the two patient groups. Positive correlations were found between muscle blood flow at Deep and pressure pain threshold in the trapezius muscle, neck movement and pain experienced at the stimulation, and negative correlations were found with spontaneous pain-related variables, symptom duration and age, pointing to less favorable results with worsening of symptoms, and to the importance of nociceptor activation in blood flow increase. It was hypothesized that the different patterns of muscle blood flow response to the needling may mirror a state of increased sympathetic activity and a generalized hypersensitivity in the patients. The intensity of stimulation should be taken into consideration when applying local needle stimulation (acupuncture) in order to increase the trapezius muscle blood flow in chronic pain conditions.

  • 37.
    Schaller, Anne
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Lindblad, Mona
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Liedberg, Gunilla M
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Health Sciences.
    Experiences of Pain: A Longitudinal, Qualitative Study of Patients with Head and Neck Cancer Recently Treated with Radiotherapy2015In: Pain Management Nursing, ISSN 1524-9042, E-ISSN 1532-8635, Vol. 16, no 3, p. 336-345Article in journal (Refereed)
    Abstract [en]

    It is not unusual for patients with head and neck cancer (HNC) to suffer from both tumor- and treatment-related pain that is difficult to alleviate despite individualized pain management. The aim of this qualitative study was to describe how HNC patients experience pain and how pain influences those who are treated with radiotherapy (RT). Qualitative semistructured interviews were performed 1 and 6 months after patients completed RT. The interviews addressed symptoms, moods, and suffering. The study included 26 patients with HNC who had recently completed RT. The interviews were analyzed using manifest content analysis. The main category was: HNC patients did not report that their severe physical pain influenced their psychological suffering, but it did influence their social lives. Furthermore, four categories were revealed: pain in the head and neck region, overwhelming fatigue, altered mood and preoccupied mind, and decreased participation and changed relationships. Physical pain, psychological distress, and social withdrawal were prominent at both interviews and consequently their situation can be considered as chronic. Remarkably, patients did not express a clear relationship between pain and psychological load. This may imply a biomedical view of pain or may reflect the difficult situation patients were in (i.e., facing a possibly life-threatening cancer). Thus, their situation might require a prioritization and might negatively affect the possibility of identifying the interaction between the different pain dimensions. The biopsychosocial model of chronic pain aims to understand the interaction between pain and psychosocial factors. Interventions aiming to teach patients with HNC how to internalize the biopsychosocial model framework to manage pain could be useful and should be evaluated in future research.

  • 38.
    Schaller, Anne
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Liedberg, Gunilla
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    How relatives of patients with head and neck cancer experience pain, disease progression and treatment: A qualitative interview study2014In: European Journal of Oncology Nursing, ISSN 1462-3889, E-ISSN 1532-2122, Vol. 18, no 4, p. 405-410Article in journal (Refereed)
    Abstract [en]

    Purpose: This study of relatives to patients with head and neck cancer (HNC) treated with radiotherapy describes how the relatives experienced the patients situation, especially with respect to pain, and how the relatives themselves experienced the situation. Methods: Semi-structured interviews of 21 relatives to HNC patients who suffered from pain were conducted, and a qualitative content analysis was performed. Results: The relatives experienced that the patients suffered from physical, psychological, and social pain. A dark picture consisting of lack of participation and knowledge, psychological distress, and lack of support were reported. Thus, a main category: relatives struggle with loved ones pains related to head and neck cancer treatment and with their own demanding situation - was based on the following four categories: inability to relieve and comprehend the physical suffering of the patients; overwhelming emotions were experienced that affect the patients and the relatives themselves; in need of support from the health care service; and altered daily activities and family roles due to illness and treatment. Conclusion: In patients physical, psychological, and social pain were prominent and in relatives psychological distress, lack of knowledge and support were experienced. Thus, to reduce pain and anxiety in patients and relatives, the health care professionals should provide relevant knowledge about pain management. The health care professionals should also provide educational interventions that address the psychological and social factors that impact pain for HNC patients and their relatives. Well-thought supporting care and easily accessible information about practical concerns should be offered to HNC patients and their relatives.

  • 39.
    Sjogaard, Gisela
    et al.
    University South Denmark.
    Rosendal, Lars
    Trial Consult, Gentofte, Denmark .
    Kristiansen, Jesper
    National Research Centre for Working Environment.
    Blangsted, Anne K
    National Research Centre for Working Environment.
    Skotte, Jorgen
    National Research Centre for Working Environment.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Saltin, Bengt
    University of Copenhagen.
    Sogaard, Karen
    University South Denmark.
    Muscle oxygenation and glycolysis in females with trapezius myalgia during stress and repetitive work using microdialysis and NIRS2010In: EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, ISSN 1439-6319, Vol. 108, no 4, p. 657-669Article in journal (Refereed)
    Abstract [en]

    The aim of this investigation was to study female workers active in the labour market for differences between those with trapezius myalgia (MYA) and without (CON) during repetitive pegboard (PEG) and stress (STR) tasks regarding (1) relative muscle load, (2) trapezius muscle blood flow, (3) metabolite accumulation, (4) oxygenation, and (5) pain development. Among 812 female employees (age 30-60 years) at 7 companies with high prevalence of neck/shoulder complaints, clinical examination identified 43 MYA and 19 CON. At rest, during PEG, and STR the trapezius muscle was measured using (1) EMG and MMG, (2) microdialysis, and (3) NIRS. Further, subjective pain ratings were scored (VAS). EMGrms in %MVE (Maximal Voluntary EMG-activity), was significantly higher among MYA than CON during PEG (11.74 +/- A 9.09 vs. 7.42 +/- A 5.56%MVE) and STR (5.47 +/- A 5.00 vs. 3.28 +/- A 1.94%MVE). MANOVA showed a group and time effect regarding data from the microdialysis: for MYA versus CON group differences demonstrated lower muscle blood flow and higher lactate and pyruvate concentrations. Potassium and glucose only showed time effects. NIRS showed similar initial decreases in oxygenation with PEG in both groups, but only in CON a significant increase back to baseline during PEG. VAS score at rest was highest among MYA and increased during PEG, but not for CON. The results showed significant differences between CON and MYA regarding muscle metabolism at rest and with PEG and STR. Higher relative muscle load during PEG and STR, insufficient muscle blood flow and oxygenation may account for the higher lactate, pyruvate and pain responses among MYA versus CON.

  • 40.
    Sjors, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Dahlman, Joakim
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Falkmer, Torbjorn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Paediatric Habilitation Community Service.
    Gerdle, Bjorn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia2009In: BMC MUSCULOSKELETAL DISORDERS, ISSN 1471-2474, Vol. 10, no 63Article in journal (Refereed)
    Abstract [en]

    Background: Repetitive and stressful work tasks have been linked to the development of pain in the trapezius muscle, although the underlying mechanisms still remain unclear. In earlier studies, it has been hypothesized that chronic muscle pain conditions are associated with imbalance in the autonomic nervous system, predominantly expressed as an increased sympathetic activity. This study investigates whether women with chronic trapezius myalgia show higher muscle activity and increased sympathetic tone at baseline and during repetitive low-force work and psychosocial stress, compared with pain-free controls. Methods: Eighteen women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON) were studied during baseline rest, 100 min of repetitive low-force work, 20 min of psychosocial stress (Trier Social Stress Test, TSST), and 80 min recovery. The subjects rated their pain intensity, stress and energy level every 20 min throughout the experiment. Muscle activity was measured by surface electromyography in the trapezius muscle (EMGtrap) and deltoid muscle (EMGdelt). Autonomic reactivity was measured through heart rate (HR), skin conductance (SCL), blood pressure (MAP) and respiration rate (Resp). Results: At baseline, EMGtrap, stress ratings, and HR were higher in MYA than in CON. Energy ratings, EMGdelt, SCL, MAP and Resp were, however, similar in the two groups. Significant main group effects were found for pain intensity, stress ratings and EMGtrap. Deltoid muscle activity and autonomic responses were almost identical in MYA and CON during work, stress and recovery. In MYA only, pain intensity and stress ratings increased towards the end of the repetitive work. Conclusion: We found increased muscle activity during uninstructed rest in the painful muscle of a group of women with trapezius myalgia. The present study could not confirm the hypothesis that chronic trapezius myalgia is associated with increased sympathetic activity. The suggestion of autonomic imbalance in patients with chronic local or regional musculoskeletal pain needs to be further investigated.

  • 41.
    Sjörs, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Karlson, Björn
    Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Sweden.
    Österberg, Kai
    Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Sweden.
    Dahlman, Joakim
    Human Factors, Shipping and Marine Technology, Chalmers University of Technology, Göteborg, Sweden.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Salivary cortisol response to acute stress and its relation to psychological factors in women with chronic trapezius myalgia – a pilot study2010In: Psychoneuroendocrinology, ISSN 0306-4530, E-ISSN 1873-3360, Vol. 35, no 5, p. 674-685Article in journal (Refereed)
    Abstract [en]

    This study investigated differences in HPA axis function, measured as salivary cortisol concentrations, between 18 women with chronic trapezius myalgia (MYA) and 30 healthy female controls. In addition, the interactions between HPA axis reactions to psychosocial stress and aspects of pain, health and psychological symptoms were analyzed. Salivary cortisol was measured both in daily life, to assess the circadian profile, and in the laboratory during light repetitive work and standardized psychosocial stress (Trier Social Stress Test, TSST). MYA and CON exhibited similar circadian rhythms and comparable salivary cortisol response magnitudes after TSST. In subjects defined as responders to the TSST, the mean peak time point of the cortisol response after TSST differed significantly between MYA and CON. Furthermore, negative psychological states and higher pain intensity were related to a slower HPA axis response to TSST. Low circadian variations in cortisol and smaller cortisol responses to TSST were found among subjects scoring high on anxiety sensitivity. Thus, a relatively favorable sample of female chronic trapezius myalgia patients exhibited normal circadian rhythm and normal salivary cortisol response magnitudes after a psychosocial stress test. In the subgroup of responders, the MYA group showed indications of a slower salivary cortisol response to psychosocial stress. Further studies are needed to elucidate the possibility of altered HPA axis activity in terms of a slower salivary cortisol response.

  • 42.
    Sjörs, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Persson, Ann L
    Rehabil and Research Centre Torture Victims, Copenhagen.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain2011In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 12, p. 230-230Article in journal (Refereed)
    Abstract [en]

    Background: Neck-shoulder pain conditions, e. g., chronic trapezius myalgia, have been associated with sensory disturbances such as increased sensitivity to experimentally induced pain. This study investigated pain sensitivity in terms of bilateral pressure pain thresholds over the trapezius and tibialis anterior muscles and pain responses after a unilateral hypertonic saline infusion into the right legs tibialis anterior muscle and related those parameters to intensity and area size of the clinical pain and to psychological factors (sleeping problems, depression, anxiety, catastrophizing and fear-avoidance). less thanbrgreater than less thanbrgreater thanMethods: Nineteen women with chronic non-traumatic neck-shoulder pain but without simultaneous anatomically widespread clinical pain (NSP) and 30 age-matched pain-free female control subjects (CON) participated in the study. less thanbrgreater than less thanbrgreater thanResults: NSP had lower pressure pain thresholds over the trapezius and over the tibialis anterior muscles and experienced hypertonic saline-evoked pain in the tibialis anterior muscle to be significantly more intense and locally more widespread than CON. More intense symptoms of anxiety and depression together with a higher disability level were associated with increased pain responses to experimental pain induction and a larger area size of the clinical neck-shoulder pain at its worst. less thanbrgreater than less thanbrgreater thanConclusion: These results indicate that central mechanisms e. g., central sensitization and altered descending control, are involved in chronic neck-shoulder pain since sensory hypersensitivity was found in areas distant to the site of clinical pain. Psychological status was found to interact with the perception, intensity, duration and distribution of induced pain (hypertonic saline) together with the spreading of clinical pain. The duration and intensity of pain correlated negatively with pressure pain thresholds.

  • 43.
    Stenström Ling, Ingrid
    et al.
    Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Individualized pharmacological treatment of oral mucositis pain in patients with head and neck cancer receiving radiotherapy2011In: Supportive Care in Cancer, ISSN 0941-4355, E-ISSN 1433-7339, Vol. 19, no 9, p. 1343-1350Article in journal (Refereed)
    Abstract [en]

    Purpose Pain is a prominent symptom in radiotherapy-induced oral mucositis (OM). This study assesses the effect of pharmacological treatment in head and neck cancer patients with OM-induced pain and swallowing difficulties. less thanbrgreater than less thanbrgreater thanMethods This study included 82 patients with head and neck cancer undergoing radiotherapy and referred to the Pain and Rehabilitation Centre at Linkoping University Hospital in Sweden because of OM-induced pain. During 1 week, pain assessment, onset of individually tailored choice of drugs, treatment evaluation, and adjustments, were undertaken. Combinations of acetaminophen, non-steroid anti-inflammatory drug (NSAID), and opioids were by steps applied. To evaluate effects, the patients answered the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-head and neck 35 in connection with the initial pain assessment and 1 week later. less thanbrgreater than less thanbrgreater thanResults Worsening of soreness in mouth and overall worsening of swallowing difficulties were seen in the patients referred within the third week of radiotherapy, showing increased severity of OM during the current week (n = 59). Pain and swallowing difficulties were unchanged in patients referred later than the third week, showing unchanged severity of OM during the current week (n = 23). less thanbrgreater than less thanbrgreater thanConclusion The answers to the questionnaire showed that the individualized pain treatment with systemic analgesics exploited to the highest degree was insufficient. Future development of pharmacological possibilities for treatment of OM-related pain is urgent. In addition, development of structured nursing care and patient self-care can contribute to improved pain relief.

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