| 1. |
- Larsson, Britt, et al.
(författare)
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The prevalences of cytochrome c oxidase negative and superpositive fibres and ragged-red fibres in the trapezius muscle of female cleaners with and without myalgia and of female healthy controls
- 2000
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Ingår i: Pain. - 1872-6623 .- 0304-3959. ; 84:2-3, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- The association of cytochrome c oxidase negative fibres (COX-negative) and ragged-red fibres (RR-fibres) with work related trapezius myalgia has been proposed. Hitherto studies have been small or without control groups. The aim of the present study was to investigate the prevalences of RR-fibres and COX-negative fibres in female cleaners with (n=25) and without (n=23) trapezius myalgia and in clinically healthy female teachers (n=21). The cleaners did mainly floor cleaning requiring monotonous loading on the trapezius muscle. A questionnaire covering background data and aspects of pain (prevalence, duration, intensity and influence on daily living) was answered. Biopsies were obtained from the trapezius muscle by an open surgical technique. The three groups did not differ in prevalence of COX-negative or COX-superpositive (i.e. type-I fibres with extremely strong brownish reaction in both the COX and SDH/COX stainings) fibres. The prevalence of COX-negative fibres was age dependent. Two subgroups of RR-fibres were present when stained for COX; COX-negative (73%) and COX-superpositive (26%) fibres. Forty-two percent of the COX-negative fibres were RR-fibres and 79% of the COX-superpositive were RR-fibres. A significantly (P=0.002) higher proportion of the COX-superpositive fibres in the cleaners were RR-fibres compared to the teachers. Multivariate regression analysis revealed that age, occupation as cleaner and a tender point in the trapezius were significantly associated with increased prevalences of RR-fibres; a cleaner with a tender point had a 4.35 higher prevalence of RR-fibres compared to a teacher without a tender point. No correlations between other pain related variables and prevalence of RR-fibres were noted. In conclusion, RR-fibres but not COX-negative or COX-superpositive fibres were correlated with cleaning work tasks and with a tender point in the trapezius.
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| 2. |
- Amandusson, Åsa, 1974-, et al.
(författare)
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Estrogen-induced alterations of spinal cord enkephalin gene expression
- 1999
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Ingår i: Pain. - : Elsevier. - 0304-3959 .- 1872-6623. ; 83:2, s. 243-248
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Tidskriftsartikel (refereegranskat)abstract
- Enkephalin-synthesizing neurons in the super®cial laminae of the spinal and trigeminal dorsal horn are critical components of the endogenous pain-modulatory system. We have previously demonstrated that these neurons display intracellular estrogen receptors, suggesting that estrogen can potentially influence their enkephalin expression. By using Northern blot, we now show that a bolus injection of estrogen results in a rapid increase in spinal cord enkephalin mRNA levels in ovariectomized female rats. Thus, 4 h after estrogen administration the enkephalin mRNA-expression in the lumbar spinal cord was on average 68% higher (P , 0:05) than in control animals injected with vehicle only. A small increase in the amount of enkephalin mRNA was also seen after 8 h (P , 0:05), whereas no difference between estrogen-injected and control animals was found after 24 h or at time periods shorter than 4 h. Taken together with the previous anatomical data, the present findings imply that estrogen has an acute effect on spinal opioid levels in areas involved in the transmission of nociceptive information.
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| 3. |
- Berglund, Birgitta, et al.
(författare)
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Quantitative and qualitative perceptual analysis of cold dysesthesia and hyperalgesia in fibromyalgia.
- 2002
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Ingår i: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 96:1-2, s. 177-87
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Tidskriftsartikel (refereegranskat)abstract
- Somatosensory perception thresholds, perceived intensity, and quality of perceptions were assessed in 20 women with fibromyalgia syndrome (FMS) and in 20 healthy age-matched female controls. All patients and controls scaled perceived intensity and described perceived quality of randomized thermal (Thermotest) and tactile (von Frey filaments) stimulation. Perceived intensity was scaled by free-number magnitude estimation and interindividual comparability was accomplished by Master Scaling. Perceived quality was assessed by choosing verbal descriptors from a list. Thenar was used as a reference for each modality tested. All patients were able to reliably scale perceived intensity at thenar, as well as in pain-affected body areas. Perception thresholds for cold pain, heat pain, cold-pain tolerance and heat-pain tolerance were significantly lower in patients than controls. For cold and tactile stimulation, the master scaled perceived intensities were significantly higher in patients' pain-affected areas, whereas for warmth/heat stimulation, the intensities were significantly lower. In the qualitative perceptual analysis the most striking and significant finding was the aberration of cold-evoked perceptions in all patients: most stimuli in the range of 30-10 degrees C were reported as heat or other paresthetic or dysesthetic perceptions. The perceptual quality of warmth, and of touch, did not differ from the controls. Another aberration was observed in the nociceptive range of thermal and of tactile stimulation as significantly more frequent pain-related descriptors than in controls. This indicates a general nociceptive facilitation in addition to the lower thermal pain thresholds. The combination of cold hyperesthesia, cold dysesthesia, and multimodal hyperalgesia suggests a selective pathophysiology at a particular level of integration, possibly in the insular cortex. It is suggested that the aberrations revealed by the supraliminal sensory evaluation may be generic for FMS. Particularly, the aberrations established in all patients for perceived quality and intensity in the cold sensory channel may be an additional diagnostic criterion.
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| 4. |
- Bergström, Gunnar, Professor, et al.
(författare)
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Reliability and factor structure of the Multidimensional Pain Inventory--Swedish Language Version (MPI-S).
- 1998
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Ingår i: Pain. - : LWW. - 0304-3959 .- 1872-6623. ; 75:1, s. 101-10
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Tidskriftsartikel (refereegranskat)abstract
- The psychological assessment of chronic pain is often accomplished using questionnaires such as the (West Haven-Yale) Multidimensional Pain Inventory ((WHY)MPI) which is constructed to capture the multidimensionality of chronic pain. The (WHY)MPI theoretically originates from behavioural and cognitive behavioural theories of pain. It is divided into three parts and measures psychosocial and behavioural consequences of pain. This questionnaire has displayed satisfactory psychometric properties and translations of the original English version into German and Dutch have been demonstrated to be reliable and valid. The aim of this study was to test the reliability and factor structure of a Swedish translation of the (WHY)MPI, the MPI-S, and also to test the generalisability of the factor structure found for the (WHY)MPI. We performed analyses of internal consistency using Cronbach's alpha, and carried out a confirmatory factor analysis (CFA) employing LISREL-8 on a population of 682 patients suffering from chronic musculoskeletal pain. Test-retest analysis was accomplished on a sub-sample of 54 individuals taken from the aforementioned population. For sections 1 and 2 of the MPI-S the overall reliability and stability were good, and after the exclusion of four items, the factor structure was similar to other versions of the MPI. For section 3, despite removal of five questions, the proposed factor structure could not be replicated. This part of the inventory is designed to measure the extent of different types of activities, and our results suggest that this section may only be used for assessing general activity level. We conclude that, with a few adjustments, the analyses yielded satisfactory results for sections 1 and 2 of the MPI-S regarding its factor structure, reliability and generalisability. For section 3 the hypothesised factor structure could not be confirmed.
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| 5. |
- Bergström, Gunnar, Professor, et al.
(författare)
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The impact of psychologically different patient groups on outcome after a vocational rehabilitation program for long-term spinal pain patients
- 2001
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Ingår i: Pain. - : LWW. - 0304-3959 .- 1872-6623. ; 93:3, s. 229-237
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Tidskriftsartikel (refereegranskat)abstract
- A better knowledge of differential treatment outcomes for subgroups of chronic spinal pain patients may, for instance, help clinicians in treatment planning or pain researchers in treatment outcome research. The purpose of this prospective study was to evaluate the predictive validity of a subgroup classification based on the Swedish version of the (West Haven Yale) Multidimensional Pain Inventory, the MPI-S. Patients referred to a vocational rehabilitation program were classified into one of three groups, labeled ‘adaptive copers’, ‘dysfunctional’ patients, and ‘interpersonally distressed’ patients, and followed over an 18-month follow-up period. The outcome variables were absence from work (defined as sick listing plus early retirement), general health status, and utilization of health care resources. To our knowledge, the predictive validity of the MPI subgroups has not been evaluated regarding sick listing and early retirement after rehabilitation. As hypothesized, the results showed that the ‘dysfunctional’ patient group had significantly more registered absences from work and reported higher utilization of health care, over the follow-up period compared to the ‘adaptive copers’. Furthermore, as hypothesized, the ‘interpersonally distressed’ and ‘dysfunctional’ patient groups report a poorer general health status than the ‘adaptive copers’ over the whole follow-up period. However, contrary to our hypothesis, the proportion of improved patients did not differ significantly between the subgroups. Altogether, the predictive validity of the MPI-S subgroup classification was mainly confirmed. The clinical implications of this study suggest that the matching of treatment to patient needs may enhance treatment outcome, reduce pain and suffering among chronic spinal pain patients and facilitate a better health economic allocation of treatment resources.
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| 6. |
- Brattberg, Gunilla, et al.
(författare)
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The prevalence of pain among the oldest old in Sweden
- 1996
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Ingår i: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 67:1, s. 29-34
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Tidskriftsartikel (refereegranskat)abstract
- Although there is information available about pain in elderly persons, there have been very few studies about pain among the oldest old. In Sweden, 8% of the population is older than 74 years, and 2% is older than 84 years. It is the group over 74 which is growing fastest in proportion to the entire population. The aims of the present study are (a) to analyze if pain increases or decreases with age in the oldest age groups and (b) to study gender differences regarding pain. The present study of a random sample (n = 537) of the oldest old in Sweden shows that there is some evidence of decreased musculoskeletal pain with age. Among women, total reported pain decreases with age. Among men, there is an increase of reported severe pain with age. Including the results from another Swedish population survey of individuals aged 18-84, there is evidence that the prevalence of pain among the older elderly is comparable to the prevalence of pain among the middle-aged (45-64) and is higher than the prevalence among the younger elderly (65-75). Musculoskeletal pain is more common among old women than old men but for chest pain and abdominal pain there is no difference. The sex difference is more pronounced for multiple and severe pain complaints. The prevalence of mild or severe pain in any of the studied locations in the whole study group (77+) was 73% and for individuals over 85 years, 68%. For multiple pain, the figures were 47% for all older elderly (77+) and 46% for individuals over 85 years of age. For severe pain in at least one location, corresponding figures were 33% and 35%.
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| 7. |
- Buer, Nina, 1960-, et al.
(författare)
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Fear-avoidance beliefs and catastrophizing : occurrence and risk factor in back pain and ADL in the general population
- 2002
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Ingår i: Pain. - 0304-3959 .- 1872-6623. ; 99:3, s. 485-491
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Tidskriftsartikel (refereegranskat)abstract
- Fear-avoidance beliefs and catastrophizing have been shown to be powerful cognitions in the process of developing chronic pain problems and there is a need for increased knowledge in early stages of pain.The objectives of this study were therefore, firstly, to examine the occurrence of fear-avoidance beliefs and catastrophizing in groups with different degrees of non-chronic spinal pain in a general population, and secondly to assess if fear-avoidance beliefs and catastrophizing were related to current ratings of pain and activities of daily living (ADL).The study was a part of a population based back pain project and the study sample consisted of 917 men and women, 35-45 years old, either pain-free or with non-chronic spinal pain. The results showed that fear-avoidance beliefs as well as catastrophizing occur in this general population of non-patients. The levels were moderate and in catastrophizing a 'dose-response' pattern was seen, such that more the catastrophizing was, the more was pain. The study showed two relationships, which were between fear-avoidance and ADL as well as between catastrophizing and pain intensity. Logistic regression analyses were performed with 95% confidence intervals and the odds ratio for fear-avoidance beliefs and ADL was 2.5 and for catastrophizing and pain 1.8, both with confidence interval above unity. The results suggest that fear-avoidance beliefs and catastrophizing may play an active part in the transition from acute to chronic pain and clinical implications include screening and early intervention. (C) 2002 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.
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| 8. |
- Craig, AD, et al.
(författare)
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Association of spinothalamic lamina I neurons and their ascending axons with calbindin-immunoreactivity in monkey and human
- 2002
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Ingår i: Pain. - 0304-3959 .- 1872-6623. ; 97:1-2, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- The calbindin-immunoreactivity of spinothalamic (STT) lamina I neurons and their ascending axons was examined in two experiments. In the first experiment, lamina I STT neurons in macaque monkeys were double-labeled for calbindin and for retrogradely transported WGA*HRP following large (n=2) or small (n=1) injections that included the posterior thalamus. Most, but not all (78%) of the contralateral retrogradely labeled lamina I STT cells were positive for calbindin. Calbindin-immunoreactivity was not selectively associated with any particular anatomical type of lamina I STT cell, 82% of the fusiform cells, 78% of the pyramidal cells and 67% of the multipolar cells were double-labeled. In the second experiment, oblique transverse sections from upper cervical spinal segments of three macaque monkeys, one squirrel monkey and five humans were stained for calbindin-immunoreactivity. In each case, a distinct bundle of fibers was densely stained in the middle of the lateral funiculus. This matches the location of anterogradely labeled ascending lamina I axons observed in prior work in cats and monkeys, and it matches the location of the classically described 'lateral spinothalamic tract' in humans. This bundle had variable shape across cases, an observation that might have clinical significance. These findings support the view that lamina I STT neurons are involved in spinal cordotomies that reduce pain, temperature and itch sensations. ⌐ 2002 International Association for the study of Pain. Published by Elsevier Science B.V. All rights reserved.
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| 9. |
- Graven-Nilsen, T, et al.
(författare)
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Ketamine reduces muscle pain, temporal summation, and referred pain in fibromyalgia patients
- 2000
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Ingår i: Pain. - 0304-3959 .- 1872-6623. ; 85:3, s. 483-491
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Tidskriftsartikel (refereegranskat)abstract
- Central mechanisms related to referred muscle pain and temporal summation of muscular nociceptive activity are facilitated in fibromyalgia syndrome (FMS) patients. The present study assessed the effects of an NMDA-antagonist (ketamine) on these central mechanisms. FMS patients received either i.v. placebo or ketamine (0.3 mg/kg, Ketalar(«)) given over 30 min on two separate occasions. Habitual pain intensity was assessed on a visual analogue scale (VAS). Initially, 29 FMS patients received ketamine or isotonic saline to determine which patients were ketamine responders (>50% decrease in pain intensity at rest by active drug on two consecutive VAS assessments). Fifteen out of 17 ketamine-responders were included in the second part of the study. Before and after ketamine or placebo, experimental local and referred pain was induced by intramuscular (i.m.) infusion of hypertonic saline (0.7 ml, 5%) into the tibialis anterior (TA) muscle. The saline-induced pain intensity was assessed on an electronic VAS, and the distribution of pain drawn by the subject. In addition, the pain threshold (PT) to i.m. electrical stimulation was determined for single stimulus and five repeated (2 Hz, temporal summation) stimuli. The pressure PT of the TA muscle was determined, and the pressure PT and pressure pain tolerance threshold were determined at three bilaterally located tenderpoints (knee, epicondyle, and mid upper trapezius). VAS scores of pain at rest were progressively reduced during ketamine infusion compared with placebo infusion. Pain intensity (area under the VAS curve) to the post-drug infusion of hypertonic saline was reduced by ketamine (-18.4▒0.3% of pre-drug VAS area) compared with placebo (29.9▒18.8%, P<0.02). Local and referred pain areas were reduced by ketamine (-12.0▒14.6% of pre-drug pain areas) compared with placebo (126.3▒83.2%, P<0.03). Ketamine had no significant effect on the PT to single i.m. electrical stimulation. However, the span between the PT to single and repeated i.m. stimuli was significantly decreased by the ketamine (-42.3▒15.0% of pre-drug PT) compared with placebo (50.5▒49.2%, P<0.03) indicating a predominant effect on temporal summation. Mean pressure pain tolerance from the three paired tenderpoints was increased by ketamine (16.6▒6.2% of pre-drug thresholds) compared with placebo (-2.3▒4.9%, P<0.009). The pressure PT at the TA muscle was increased after ketamine (42.4▒9.2% of pre-drug PT) compared with placebo (7.0▒6.6%, P<0.011). The present study showed that mechanisms involved in referred pain, temporal summation, muscular hyperalgesia, and muscle pain at rest were attenuated by the NMDA-antagonist in FMS patients. It suggested a link between central hyperexcitability and the mechanisms for facilitated referred pain and temporal summation in a sub-group of the fibromyalgia syndrome patients. Whether this is specific for FMS patients or a general phenomena in painful musculoskeletal disorders is not known. Copyright (C) 2000 International Association for the Study of Pain. Published by Elsevier Science B.V.
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| 10. |
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