European journal of pain : EJP
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We have studied scalding-type burn injury-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in the spinal dorsal horn, which is a recognised marker for spinal nociceptive processing. At 5min after severe scalding injury to mouse hind-paw, a substantial number of phosphorylated ERK1/2 (pERK1/2) immunopositive neurons were found in the ipsilateral dorsal horn. At 1h post-injury, the number of pERK1/2-labelled neurons remained substantially the same. ⋯ By 6h post-injury, the number of labelled neurons was reduced on both sides without there being significant difference between the two sides. A similar pattern of severe scalding injury-induced activation of ERK1/2 in spinal dorsal horn neurons over the same time-course was found in mice which lacked the transient receptor potential type 1 receptor (TRPV1) except that the extent to which ERK1/2 was activated in the ipsilateral dorsal horn at 5 min post-injury was significantly greater in wild-type animals when compared to TRPV1 null animals. This difference in activation of ERK1/2 in spinal dorsal horn neurons was abolished within 1h after injury, demonstrating that TRPV1 is not essential for the maintenance of ongoing spinal nociceptive processing in inflammatory pain conditions in mouse resulting from at least certain types of severe burn injury.
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Despite using prescribed pain medications, patients with neuropathic pain continue to experience moderate to severe pain. There is a growing recognition of a potent peripheral opioid analgesia in models of inflammatory and neuropathic pain. The goal of this study was to characterize the temporal and spatial expression of mu opioid receptor (mOR) mRNA and protein in primary afferent neurons in a rat L5 spinal nerve ligation model of persistent neuropathic pain. ⋯ Western blot analysis revealed a persistent increase in mOR protein expression, although immunohistochemistry showed no change in number of mOR-positive neurons in the uninjured L4 DRG. Interestingly, mOR protein expression was reduced in the skin on days 14 and 35 post-nerve injury and in the L4 and L5 spinal cord on day 35 post-nerve injury. These temporal and anatomically specific changes in mOR expression following nerve injury are likely to have functional consequences on pain-associated behaviors and opioid analgesia.
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Multicenter Study
Multi-centre European study of breakthrough cancer pain: pain characteristics and patient perceptions of current and potential management strategies.
This study involved 320 cancer patients from four Northern European countries. Patients with breakthrough pain were questioned about the characteristics of their pain, the current management of their pain, and the acceptability/utility of alternative routes of administration. The median number of episodes was 3/day. ⋯ Forty-two percent patients would definitely consider using an intranasal product, with 26% patients stating they would definitely not use such a preparation; patients from Denmark and Sweden were less likely to answer positively, and a positive response was associated with male gender, and previous use of the route. Forty-four percent patients reported regular nasal problems. Sixty percent patients would definitely consider using a subcutaneous product, and 44% patients would definitely consider using an intrapulmonary product.
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To assess whether symptoms of fibromyalgia (FM) predict disability retirement or mortality. ⋯ Symptoms associated with FM strongly correlate with early disability retirement. Lifestyle problems associated with high symptom load need prompt management to avoid increased risk of mortality.
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Major efforts to develop objective measurement tools for neonatal pain assessment have been made. However, the challenge of measuring pain in neonates remains suggesting that contextual factors (cFs) might alter their responses to pain. Although the role of cFs is increasingly discussed as crucial for pain assessment, they are not well described in the literature and are rarely considered in the clinical setting despite their importance. ⋯ This review supports the influence of some cFs on pain response. However, the results remain inconclusive which may be, in part, related to the heterogeneity of the studies. Contextual factors need further investigation for a better understanding of the magnitude of their effect on pain response.