European journal of pain : EJP
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We previously found that for both men and women odors influence mood, which in turn influences pain unpleasantness perception. Others showed that the steroid androstadienone modulates mood differently in men and women, improving mood in women and worsening it or leaving it unchanged in men. Based on its dissociable effect on mood, we hypothesized that women exposed to androstadienone would report lower pain unpleasantness than when exposed to the vehicle, while men would show no change or the reverse pattern. Because of the expected beneficial effect of pleasant odors on mood in both men and women, all subjects should report lower pain unpleasantness when exposed to the pleasant odor compared to the unscented air. ⋯ Planned comparisons confirmed that, in the absence of pain, androstadienone improved mood only in women, while the pleasant odorants improved mood for all subjects. However, these positive mood changes did not persist with the introduction of pain. Consistent with the absence of positive mood changes, pain unpleasantness was not modulated. Unexpectedly, the presence of androstadienone increased perceived pain intensity especially in women, suggesting an effect of androstadienone on pain perception, independent of mood changes. Heightened attentional state may be responsible.
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Mounting evidence supports the hypothesis that spinal microglia modulate the development and maintenance of some chronic pain states. Here we examined the role of spinal microglia following both peripheral inflammatory insult and peripheral nerve injury. We observed significant ipsilateral dorsal horn microglia activation 2 weeks after injury and bilateral activation 50 days following nerve injury as well as 24 h following intraplantar zymosan but not intraplantar complete Freund's adjuvant (CFA). ⋯ These data suggest a role for spinal glia in the persistence of mechanical hyperalgesia following peripheral nerve injury. However, activation of spinal microglia contralaterally did not correlate to nociception. Furthermore, it would appear that the time course of microglia activation and their contribution to inflammatory pain is dependent on the inflammatory stimulus administered.
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Multicenter Study
Adult attachment variables predict depression before and after treatment for chronic pain.
The complex relationship between chronic pain and depression has long been of clinical and empirical interest. Although attachment theory has been described as a "theory of affect regulation", and has been lauded as a developmental framework for chronic pain, surprisingly little research specifically considers the links between adult attachment variables and pain-related depression. ⋯ Of particular interest was the finding that comfort with closeness was the unique predictor of lower levels of post-treatment depression, usurping pain intensity and pre-treatment depression. These results are discussed in terms of clinical implications, and suggest that adult attachment theory may prove a valuable perspective in pain treatment programs.
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The etiology of complex regional pain syndrome (CRPS) is unclear yet. Recently autoantibodies and antecedent viral infections have been discussed to be involved in the pathogenesis of CRPS. ⋯ All CRPS 2 patients were positive. 10.2% of the CRPS patients and 10.0% of the controls had AECA (n.s.) and AECA were not associated with parvovirus B19 seropositivity. Our findings suggest the involvement of parvovirus B19, but not autoantibody-mediated endothelial cell damage, in the pathogenesis of CRPS.
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Evoked or experimental pain is often used as a model for the study of clinical pain, yet there are little data regarding the relationship between the two. In addition, there are few data regarding the types of stimuli and stimulus intensities that are most closely related to clinical pain. In this study, 36 subjects with fibromyalgia (FM), chronic fatigue syndrome (CFS), or both syndromes were administered measures of clinical pain and underwent a dolorimetry evaluation. ⋯ Both intensity and unpleasantness ratings of pressure delivered using random staircase methods were significantly associated with clinical pain at low, moderate and high levels, and the strength of the association was greater at increasingly noxious stimulus intensities. These findings suggest that random pressure stimulation as an experimental pain model in these populations more closely reflects the clinical pain for these conditions. These findings merit consideration when designing experimental studies of clinical pain associated with FM and CFS.