Pain
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Chronic and recurrent pain not associated with a disease is very common in childhood and adolescence, but studies of pain prevalence have yielded inconsistent findings. This systematic review examined studies of chronic and recurrent pain prevalence to provide updated aggregated prevalence rates. The review also examined correlates of chronic and recurrent pain such as age, sex, and psychosocial functioning. ⋯ Pain prevalence rates were generally higher in girls and increased with age for most pain types. Lower socioeconomic status was associated with higher pain prevalence especially for headache. Most studies did not meet quality criteria.
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Randomized Controlled Trial Comparative Study
TRP-channel-specific cutaneous eicosanoid release patterns.
Analyzing mechanisms and key players in peripheral nociception nonneuronal skin cells are getting more and more into focus. Herein we investigated the functional expression of TRPV1 and TRPA1 in human keratinocytes and fibroblasts and assessed proinflammatory lipid mediator release upon their stimulation as well as sensory effects after topical application, combining in vitro and in vivo approaches. In vitro, the expression of functional TRPV1 and TRPA1 channels on fibroblasts and keratinocytes was confirmed via immunofluorescence, qualitative real time (RT) polymerase chain reaction, and cellular Ca(2+) influx measurements. ⋯ In parallel, heat pain thresholds were reduced by both agents after short-term topical application, but only AITC provoked a long-lasting local erythema. In conclusion, the agonist-induced activation of nociceptors by TRPA1 and TRPV1 elicits painful sensations, whereas nonneuronal tissue cells respond with differential release of inflammatory mediators, thus influencing local vasodilatation and neuronal sensitization. These results have implications for the application of transient receptor potential antagonists to improve inflammatory skin conditions and pain management.
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Persistent postoperative pain is a common complication of surgery, including surgical interventions for cancer. So far, there is limited information about the prevalence and clinical characteristics of pain after lymph node biopsy and dissection in patients with malignant melanoma. In this study, a questionnaire was sent out to all surviving patients (n=402) after surgery for cutaneous malignant melanoma at the Aalborg Hospital Department of Plastic Surgery, Aalborg, Denmark. ⋯ At the clinical follow-up, 10 out of 12 patients with pain both met the criteria of the recently proposed grading system for probable neuropathic pain and used descriptors on the DN4 questionnaire suggestive of neuropathic pain. Different patterns of sensory profiles were observed in single patients, suggesting heterogeneous sensory processing within single patients. This study suggested that nerve injury was the main underlying mechanism of persistent pain after lymph node excision.
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Complex regional pain syndrome (CRPS) is a painful condition affecting one or more extremities of the body, marked by a wide variety of symptoms and signs that are often difficult to manage because the pathophysiology is incompletely understood. Thus, diverse treatments might be ineffective. A recent report revealed the presence of autoantibodies against differentiated autonomic neurons in CRPS patients. ⋯ We identified these autoantibodies as immunoglobulin G directed against peptide sequences from the second extracellular loop of these receptors. The identification of functionally active autoantibodies in serum samples from CRPS patients supports an autoimmune pathogenesis of CRPS. Thus, our findings contribute to the further understanding of this disease, could help in the diagnosis in future, and encourage new treatment strategies focusing on the immune system.
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The human 'pain network' includes cortical areas that are activated during the response to painful stimuli (termed category 1) or during psychological processes that modulate pain, for example, distraction (termed category 2). These categories include parts of the parasylvian (PS), medial frontal (MF), and paracentral cortex (S1&M1). Here we test the hypothesis that causal interactions both within and between category 1 and category 2 modules occur during attention to a painful stimulus. ⋯ The proportion of contacts involved in interactions with PS was greater during distraction vs attention while activation was less, which suggests that distraction involves an inhibitory process in PS. Functional interactions between categories were overwhelmingly in the direction from category 2>1, particularly for contacts in MF which often had a driver role. These results demonstrate that MF is densely interconnected throughout the 'pain network' so that stimulation of MF might be used to disrupt the 'pain network' as a therapy for pain.