Pain
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Bradykinin (BK) is an inflammatory mediator that can evoke oedema and vasodilatation, and is a potent algogen signalling via the B1 and B2 G-protein coupled receptors. In naïve skin, BK is effective via constitutively expressed B2 receptors (B2R), while B1 receptors (B1R) are purported to be upregulated by inflammation. The aim of this investigation was to optimise BK delivery to investigate the algesic effects of BK and how these are modulated by inflammation. ⋯ We have optimised a versatile experimental model by which BK and its analogues can be administered to human skin. We have found that there is an early phase of BK-induced pain which partly depends on the release of inflammatory mediators by MCs; however, subsequent hyperalgesia is not dependent on MC degranulation. In naïve skin, B2R signaling predominates, however, cutaneous inflammation results in enhanced B1R responses.
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The present study investigated the role of observer pain catastrophizing and personal pain experience as possible moderators of attention to varying levels of facial pain expression in others. Eye movements were recorded as a direct and continuous index of attention allocation in a sample of 35 undergraduate students while viewing slides presenting picture pairs consisting of a neutral face combined with either a low, moderate, or high expressive pain face. Initial orienting of attention was measured as latency and duration of first fixation to 1 of 2 target images (i.e., neutral face vs pain face). ⋯ With respect to attentional maintenance, participants reporting high catastrophizing and pain intensity demonstrated significantly longer gaze duration for all face types (neutral and pain expression), relative to low catastrophizing counterparts. Finally, independent of catastrophizing, higher reported pain intensity contributed to decreased attentional maintenance to pain faces vs neutral faces. Theoretical implications and further research directions are discussed.
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Randomized Controlled Trial
Efficacy of melatonin in the treatment of endometriosis: a phase II, randomized, double-blind, placebo-controlled trial.
Endometriosis-associated chronic pelvic pain (EACPP) presents with an intense inflammatory reaction. Melatonin has emerged as an important analgesic, antioxidant, and antiinflammatory agent. This trial investigates the effects of melatonin compared with a placebo on EACPP, brain-derived neurotrophic factor (BDNF) level, and sleep quality. ⋯ Melatonin improved sleep quality, reduced the risk of using an analgesic by 80%, and reduced BNDF levels independently of its effect on pain. This study provides additional evidence regarding the analgesic effects of melatonin on EACPP and melatonin's ability to improve sleep quality. Additionally, the study revealed that melatonin modulates the secretion of BDNF and pain through distinct mechanisms.
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Randomized Controlled Trial
The Pain Course: a randomised controlled trial of a clinician-guided Internet-delivered cognitive behaviour therapy program for managing chronic pain and emotional well-being.
The present study evaluated the efficacy of a clinician-guided Internet-delivered cognitive behaviour therapy (iCBT) program, the Pain Course, to reduce disability, anxiety, and depression associated with chronic pain. Sixty-three adults with chronic pain were randomised to either a Treatment Group or waitlist Control Group. Treatment consisted of 5 iCBT-based lessons, homework tasks, additional resources, weekly e-mail or telephone contact from a Clinical Psychologist, and automated e-mails. ⋯ These outcomes were sustained at follow-up and participants rated the program as highly acceptable. Overall, the clinician spent a total mean time of 81.54 minutes (SD 30.91 minutes) contacting participants during the program. The results appear better than those reported in iCBT studies to date and provide support for the potential of clinician-guided iCBT in the treatment of disability, anxiety, and depression for people with chronic pain.