Pain
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Negatively biased memories for pain (ie, recalled pain is higher than initial report) robustly predict future pain experiences. During early childhood, parent-child reminiscing has been posited as playing a critical role in how children's memories are constructed and reconstructed; however, this has not been empirically demonstrated. This study examined the role of parent-child reminiscing about a recent painful surgery in young children's pain memory development. ⋯ Greater parental use of pain words predicted more negatively biased pain memories. Although there were no sex and parent-role differences in pain memory biases, mothers and fathers differed in how they reminisced with their boys vs girls. This research underscores the importance of parent-child reminiscing in children's pain memory development and may be used to inform the development of a parent-led memory reframing intervention to improve pediatric pain management.
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Functional abdominal pain disorders (FAPDs) are common among young individuals. To date, relatively little is known regarding the function of the endogenous analgesic mechanisms in this vulnerable group. Therefore, this case-control study aimed to compare conditioned pain modulation (CPM), pressure algometry, and psychosocial variables in 39 young children (aged 6-12 years) with FAPD and 36 age- and sex-matched pain-free controls. ⋯ Parents of children with FAPD catastrophized more about their child's pain than parents of healthy children (P < 0.001). No sex differences were found for the experimental pain measurements (P > 0.05), nor was there a significant correlation between the child- and parent-reported questionnaires and the CPM effect (P > 0.05). In summary, young children with FAPD demonstrated secondary hyperalgesia and decreased functioning of endogenous analgesia.
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Data from preclinical research have been suggested to suffer from a lack of inherent reproducibility across laboratories. The goal of our study was to replicate findings from a previous report that demonstrated positive effects of Meteorin, a novel neurotrophic factor, in a rat model of neuropathic pain induced by chronic constriction injury (CCI). Notably, 5 to 6 intermittent subcutaneous (s.c.) injections of Meteorin had been reported to produce reversal of mechanical allodynia/thermal hyperalgesia after injury, wherein maximum efficacy of Meteorin was reached slowly and outlasted the elimination of the compound from the blood by several weeks. ⋯ Systemic administration of recombinant mouse Meteorin (0.5 and 1.8 mg/kg, s.c.) at days 10, 12, 14, 17, and 19 after CCI produced a prolonged reversal of neuropathic hypersensitivity with efficacy comparable with that obtained with gabapentin (100 mg/kg, orally). Despite some protocol deviations (eg, nociceptive endpoint, animal vendor, testing laboratory, investigator, etc.) being incurred, these did not affect study outcome. By paying careful attention to key facets of study design, using bioactive material, and confirming drug exposure, the current data have replicated the salient findings of the previous study, promoting confidence in further advancement of this novel molecule as a potential therapy for neuropathic pain.
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Residual lower-limb pain after low back surgery (postsurgical sciatica) and complex regional pain syndrome (CRPS) involving a lower limb are separate conditions but may share some mechanisms (eg, tissue inflammation, neuroimmune disturbances, and central neuroplasticity). As adrenergically evoked pain contributes, in part, to CRPS, whether an adrenergic mechanism also contributes to postsurgical sciatica was investigated in this study. Immunohistochemistry was used to identify α1-adrenoceptors (α1-AR) on nerve fibres and other targets in the affected and contralateral skin of 25 patients with postsurgical sciatica, and α1-AR expression was investigated in relation to pain and pinprick hyperalgesia after intradermal injection of the α1-AR agonist phenylephrine. ⋯ Sensitivity to pressure-pain, pinprick, and cold-pain was greater in the ipsilateral than contralateral forehead of the entire cohort, but sensory disturbances were most pronounced in patients with additional CRPS-like features. Together, these findings suggest that bilateral distal neuropathy and central neuroplastic changes are involved not only in the pathophysiology of CRPS but also in postsurgical sciatica. This may have treatment implications for patients with postsurgical sciatica.