European journal of pain : EJP
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The neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) play a pivotal role in the generation and maintenance of hyperalgesia. In the present study we analyzed NGF and BDNF levels in human skin of the upper arm and axilla skin sites by dermal microdialysis and multiplexed assay. Skin sensitization and inflammatory responses were evoked experimentally by repetitive shaving of one axilla provoking local erythema and reduced heat pain thresholds. ⋯ On average, NGF levels were analyzed at 14.6 fg/microg/ml and BDNF values at 202 fg/microg/ml. These data demonstrate enhanced level of neurotrophin release in inflamed human skin in vivo which might well contribute to peripheral sensitization. Analyses of neurotrophic factors by dermal microdialysis are useful endogenous markers to further explore their role in neuronal sensitization processes in human.
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Comparative Study
Comparison of dorsal root ganglion gene expression in rat models of traumatic and HIV-associated neuropathic pain.
To elucidate the mechanisms underlying peripheral neuropathic pain in the context of HIV infection and antiretroviral therapy, we measured gene expression in dorsal root ganglia (DRG) of rats subjected to systemic treatment with the anti-retroviral agent, ddC (Zalcitabine) and concomitant delivery of HIV-gp120 to the rat sciatic nerve. L4 and L5 DRGs were collected at day 14 (time of peak behavioural change) and changes in gene expression were measured using Affymetrix whole genome rat arrays. Conventional analysis of this data set and Gene Set Enrichment Analysis (GSEA) was performed to discover biological processes altered in this model. ⋯ We identified 39 genes/expressed sequence tags that are differentially expressed in the same direction in both models. Most of these have not previously been implicated in mechanical hypersensitivity and may represent novel targets for therapeutic intervention. As an external control, the RNA expression of three genes was examined by RT-PCR, while the protein levels of two were studied using western blot analysis.
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Emerging evidence indicates that meanings attributed to pain contribute to tolerance and coping among affected individuals. However, links between pain appraisals and coping responses have received little attention within a broader interpersonal context. In this experiment, effects of appraisal on pain tolerance and coping were examined in adult dyads. ⋯ Pain language was also most prominent in transactions of threatened dyads. Finally, use of attention diversion by observers contributed to pain tolerance, independent of participant factors (reported pain, appraisal condition, reported coping) and pain language in conversations during immersions. The study highlights how appraisal contributes not only to pain tolerance and coping in the affected individual but also to care-giving efforts of others in their social environment.
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A task group of the Science Committee of the Association for Palliative Medicine of Great Britain and Ireland (APM) was convened to produce some up-to-date, evidence-based, practical, clinical guidelines on the management of cancer-related breakthrough pain in adults. On the basis of a review of the literature, the task group was unable to make recommendations about any individual interventions, but was able to make a series of 12 recommendations about certain generic strategies. However, most of the aforementioned recommendations are based on limited evidence (i.e., case series, expert opinion). The task group also proposed a definition of breakthrough pain, and some diagnostic criteria for breakthrough pain.