Pain
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Randomized Controlled Trial Multicenter Study
Acupuncture in patients with acute low back pain: a multicentre randomised controlled clinical trial.
Reviews of the efficacy of acupuncture as a treatment for acute low back pain have concluded that there is insufficient evidence for its efficacy and that more research is needed to evaluate it. A multicentre randomized controlled trial was conducted at 4 primary-care centres in Spain to evaluate the effects of acupuncture in patients with acute nonspecific low back pain in the context of primary care. A total of 275 patients with nonspecific acute low back pain (diagnosed by their general practitioner) were recruited and assigned randomly to 4 different groups: conventional treatment either alone or complemented by 5 sessions over a 2-week period of true acupuncture, sham acupuncture, or placebo acupuncture per patient. ⋯ The primary outcome was the reduction in Roland Morris Disability Questionnaire scores of 35% or more after 2weeks' treatment. The patients in the 3 types of acupuncture groups were blinded to the treatments, but those who received conventional treatment alone were not. In the analysis adjusted for the total sample (true acupuncture relative risk 5.04, 95% confidence interval 2.24-11.32; sham acupuncture relative risk 5.02, 95% confidence interval 2.26-11.16; placebo acupuncture relative risk 2.57 95% confidence interval 1.21-5.46), as well as for the subsample of occupationally active patients, all 3 modalities of acupuncture were better than conventional treatment alone, but there was no difference among the 3 acupuncture modalities, which implies that true acupuncture is not better than sham or placebo acupuncture.
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Sex differences in the spinal processing of somatic and visceral stimuli contribute to greater female sensitivity in many pain disorders. The present study examined spinal mechanisms that contribute to sex differences in visceral sensitivity. The visceromotor response to colorectal distention (CRD) was more robust in normal female rats and after intracolonic mustard oil compared with that in male rats. ⋯ After intracolonic mustard oil, there was no longer a sex difference in the effect of APV nor GluN1 expression in LS segments, but greater female expression in TL segments. These data document a sex difference in spinal processing of nociceptive visceral stimuli from the normal and inflamed colon. Differences in dorsal horn neuronal activity and NMDA receptor expression contribute to the sex differences in the visceral sensitivity observed in awake rats.
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The manifestation of chronic, neuropathic pain includes elevated levels of the cytokine tumor necrosis factor-alpha (TNF). Previously, we have shown that the hippocampus, an area of the brain most notable for its role in learning and memory formation, plays a fundamental role in pain sensation. Using an animal model of peripheral neuropathic pain, we have demonstrated that intracerebroventricular infusion of a TNF antibody adjacent to the hippocampus completely alleviated pain. ⋯ Sensitivity to mechanical stimulation also developed bilaterally in the rat hind paws. In support of these behavioral findings, immunoreactive staining for TNF, bioactive levels of TNF, and levels of TNF mRNA per polymerase chain reaction analysis were assessed in several brain regions and found to be increased only in the hippocampus. These findings indicate that the specific elevation of TNF in the hippocampus is not a consequence of pain, but in fact induces these behaviors/symptoms.
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Randomized Controlled Trial Multicenter Study
Randomized control trial of topical clonidine for treatment of painful diabetic neuropathy.
A length-dependent neuropathy with pain in the feet is a common complication of diabetes (painful diabetic neuropathy). It was hypothesized that pain may arise from sensitized-hyperactive cutaneous nociceptors, and that this abnormal signaling may be reduced by topical administration of the α(2)-adrenergic agonist, clonidine, to the painful area. This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. ⋯ In subjects with a capsaicin pain rating ⩾2 (0-10, NPRS), the mean decrease in foot pain was 2.6 for active compared to 1.4 for placebo (P=0.01). Topical clonidine gel significantly reduces the level of foot pain in painful diabetic neuropathy subjects with functional (and possibly sensitized) nociceptors in the affected skin as revealed by testing with topical capsaicin. Screening for cutaneous nociceptor function may help distinguish candidates for topical therapy for neuropathic pain.