European journal of pain : EJP
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The purpose of this study was to investigate the pressure pain thresholds (PPTs) with respect to the Erector spinae and the hip muscles in 87 patients with subacute non-specific low back pain (LBP) and to evaluate the relationship between the PPTs and disability. In order to establish reference values, 64 healthy subjects were examined with respect to PPTs and used as a control group against the group of LBP patients. The mean PPT values of the Erector spinae and the hip at all examined points of the LBP group were significantly lower (p<0.001) in comparison to the PPT values of the healthy group. ⋯ The correlation between having LBP or not in the whole group (n=151) and PPT, was highest at the L3 level of the Erector spinae (r=-0.710, p<0.001). When the group of patients with LBP was divided into two subgroups in terms of having an Oswestry disability index (ODI) lower than 40 ("moderate LBP disability") or an ODI higher than 40 ("severe LBP disability") it was surprising to notice that there was no significant difference between the PPTs of the Erector spinae and the hip musculature. This study has shown the possibility of the existence of muscular disorder in the lumbar part of the Erector spinae in patients with non-specific low back pain, but also reveals the strong inter-individual differences in muscular fibrosis sensitivity and pain behaviour related to gender.
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It is well known that the response to painful stimuli varies between individuals and this could be consequence of individual differences to pain sensitivity that may be related to genetic factors. Catechol-O-methyltransferase (COMT) is one of the enzymes that metabolize catecholamine neurotransmitters. Differences in the activity of COMT influence the functions of these neurotransmitters. ⋯ To elucidate the possible role of COMT polymorphism in the susceptibility to neuropathic pain, we have performed a case-control study in a Spanish population. Analysis of the (Val158Met) COMT polymorphism was performed by PCR amplification and DNA digestion with restriction enzymes. Our study concludes that functional Val158Met polymorphism of COMT gene is not associated to increased susceptibility to neuropathic pain.
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Glutamate may be released from muscle nociceptors and thereby contribute to mechanisms underlying acute and chronic muscle pain. In vivo concentration of glutamate during muscle pain has not previously been studied in either animals or humans. In the present study, we aimed to study the in vivo concentration of glutamate before, during and after acute pain of trapezius muscle in humans using the microdialysis technique. ⋯ Muscle blood flow increased significantly over time in response to infusion of chemical mixture and placebo (p = 0.001). However, we found no difference in changes in muscle blood flow between chemical mixture and placebo (p > 0.05). In conclusion, the present study demonstrates no signs of increased release of glutamate from myofascial nociceptors during and after acute experimentally induced muscle pain and tenderness.
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This study was designed to assess the impact of a refractory angina programme on the health related quality of life for patients with chronic refractory angina (CRA) one year following enrolment. ⋯ Implementation of the national refractory angina guidelines in a prospective study of 69 consecutive CRA patients significantly improved health related quality of life status at one year.
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Pain possesses both sensory and affective dimensions, which are highly correlated yet distinct. Comparison of these dimensions within experimental pain settings has resulted in the construct of relative unpleasantness. Relative unpleasantness is defined as the amount of affective unpleasantness elicited for a given sensory magnitude. ⋯ Relative unpleasantness was not correlated with distress, anxiety, or depression, which were pronounced in the FM group. Clinical pain in patients with FM was perceived to be more unpleasant than the evoked pain stimuli. These results are consistent with the concept that chronic pain may reduce the relative unpleasantness of evoked pain sensations.