The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial Multicenter Study
The Relationship of Endocannabinoidome Lipid Mediators With Pain and Psychological Stress in Women With Fibromyalgia: A Case-Control Study.
Characterized by chronic widespread pain, generalized hyperalgesia, and psychological stress, fibromyalgia (FM) is difficult to diagnose and lacks effective treatments. Endocannabinoids-arachidonoylethanolamide (AEA), 2-arachidonoylglycerol (2-AG), and the related oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and stearoylethanolamide (SEA)-are endogenous lipid mediators with analgesic and anti-inflammatory characteristics, in company with psychological modulating properties (eg, stress and anxiety), and are included in a new emerging "ome," the endocannabinoidome. This case-control study compared the concentration differences of AEA, OEA, PEA, SEA, and 2-AG in 104 women with FM and 116 healthy control subjects. ⋯ Thus plasma lipids alone are not good biomarkers for FM. PERSPECTIVE: This study reports about elevated plasma levels of endocannabinoidome lipid mediators in FM. The lipids' suitability to work as biomarkers for FM in the clinic were low; however, their altered levels indicate that a metabolic asymmetry is ongoing in FM, which could serve as a baseline during explorative FM pain management.
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Randomized Controlled Trial
The Influence of Placebo Analgesia Manipulations on Pain Report, the Nociceptive Flexion Reflex, and Autonomic Responses to Pain.
Expectations for pain relief and experience/conditioning are psychological factors that contribute to placebo analgesia, yet few studies have studied the physiological mechanisms underlying their effects. This study randomized 133 participants to 4 groups: an expectation only (E-only) group, a conditioning only (C-only) group, an expectation plus conditioning (E+C) group, and a natural history (NH) control group. Painful electric stimulations were delivered before and after an inert cream was applied to the site of stimulation. ⋯ PERSPECTIVE: This study assessed whether placebo analgesia manipulations that include expectations, conditioning, or both modulate the NFR (measure of spinal nociception). Only the manipulation that involved expectations and conditioning inhibited pain, but both expectation manipulations facilitated NFR. This suggests a complex modulation of spinal neurons by placebo manipulations.
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Randomized Controlled Trial
Exploring the Role of Negative Cognitions in the Relationship Between Ethnicity, Sleep, and Pain in Women With Temporomandibular Joint Disorder.
Negative cognitions are central to the perpetuation of chronic pain and sleep disturbances. Patients with temporomandibular joint disorder (TMJD), a chronic pain condition characterized by pain and limitation in the jaw area, have a high comorbidity of sleep disturbances that possibly exacerbate their condition. Ethnic group differences are documented in pain, sleep, and coping, yet the mechanisms driving these differences are still unclear, especially in clinical pain populations. ⋯ These findings identify pain catastrophizing as a potentially important link between ethnicity and clinical pain and suggest that interventions targeting pain-related helplessness could improve both sleep and pain, especially for African American patients. Perspective:Pain-related helplessness and insomnia severity contribute to ethnic differences found in clinical pain among woman with TMJD. Findings can potentially inform interventions that target insomnia and catastrophizing to assist in reducing ethnic disparities in clinical pain.