European journal of pain : EJP
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Randomized Controlled Trial
Temporal summation of pressure pain during muscle hyperalgesia evoked by nerve growth factor and eccentric contractions.
Nerve growth factor (NGF) has a key role in the generation and potentiation of pain. Its centrally sensitizing effects may facilitate pain responses to noxious stimulus. This study assessed (1) the influence of NGF on delayed onset muscle soreness (DOMS) in shoulder muscles; and (2) the temporal summation of pressure pain during hyperalgesia induced by NGF and DOMS. ⋯ The NGF injected side had higher pain ratings during temporal summation at 1s ISI compared with the contralateral side 24h after injections. Intramuscular administration of NGF intensified the DOMS responses, evoking facilitated temporal summation. Central as well as peripheral sensitization mechanisms may play a role in the facilitation.
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Cutaneous C-fiber afferents show two distinct types of cold sensitivity corresponding to non-noxious and noxious cold sensations. Here, responses to cold stimulation of afferent fibers regenerating in the rat sural nerve were studied in vivo 7-14 days after nerve crush and compared with responses to mechanical and heat stimulation. The physiological stimuli were applied to the sural nerve at or distal to the lesion site. ⋯ They were also heat-sensitive (n=25) and/or mechanosensitive (n=20). These C-fibers were, apart from their cold sensitivity, functionally indistinguishable from C-fibers with mechano- and/or heat sensitivity only. Thus regenerating cutaneous C-fibers show two types of cold sensitivity similar to those observed in intact skin: fibers of one group are predominantly sensitive to cooling, whereas the others are polymodal.
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Review Meta Analysis
Psychosocial predictors and correlates for chronic post-surgical pain (CPSP) - a systematic review.
Chronic post-surgical pain (CPSP) is a serious problem. Incidence as high as 50% has been reported, depending on type of surgery undergone. Because the etiology of chronic pain is grounded in the bio-psychosocial model, physical, psychological, and social factors are implicated in the development of CPSP. ⋯ Other factors were determined to have either unlikely (grade of association=3) or inconclusive (grade of association=2) correlations. In addition, results were examined in light of the type of surgery undergone. This review is intended as a first step to develop an instrument for identifying patients at high risk for CPSP, to optimize clinical pain management.
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Randomized Controlled Trial Comparative Study
Gastrointestinal symptoms under opioid therapy: a prospective comparison of oral sustained-release hydromorphone, transdermal fentanyl, and transdermal buprenorphine.
The purpose of this trial was to evaluate the effect of long-term treatment with oral sustained-release hydromorphone, transdermal fentanyl, and transdermal buprenorphine on nausea, emesis and constipation. ⋯ Gastrointestinal symptoms of cancer pain patients undergoing an opioid therapy are related to multifactorial causes. Transdermal opioids showed no benefit over oral controlled-release hydromorphone with regard to gastrointestinal symptoms. The conversion ratios for transdermal fentanyl, transdermal buprenorphine, and oral hydromorphone did not accord to the literature, because of differing occurrences of opioid tolerance after long-term therapy.
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Loss of function is usually considered the major consequence of spinal cord injury (SCI). However, pain severely compromises the quality of life in nearly 70% of SCI patients. The principal aim of this study was to assess the contribution of Tumor necrosis factor alpha (TNF-alpha) to SCI pain. ⋯ Furthermore, minocycline decreased the expression of noxious-stimulation-induced c-Fos, suggesting an effect on evoked neuronal activity. This study demonstrates that TNF-alpha plays an important role in the establishment of neuropathic pain following SCI, seemingly dependent on microglial activation. Pharmacological targeting of TNF-alpha may offer therapeutic opportunities for treating SCI pain.