Pain
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The current study examined patients with temporomandibular disorders (TMD) (n=20) and pain-free controls (n=28) under stress and relaxation conditions. Interleukin-6 (IL-6), norepinephrine and epinephrine (NE and E) were measured both before and during each of two conditions: a non-stressful relaxation period and a speech stressor. Ischemic pain sensitivity was also assessed after each of these conditions. ⋯ After controlling for depressed mood, TMD patients as a whole showed a significantly blunted response in IL-6 levels produced during stress as compared to controls (beta=0.31*). Although TMD subjects as a whole did not show the expected greater pain sensitivity to the ischemic task, those displaying a less optimistic style did exhibit lower pain tolerance times (beta=-0.61*) and higher pain unpleasantness ratings (beta=0.48*), compared with low optimism controls and high optimism TMD patients. Less optimistic TMD patients also had higher NE and IL-6 levels during stress than other TMD patients, while optimism was unrelated to responses in controls (*P<0.05).
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Transcutaneous electrical nerve stimulation (TENS) partially reduces primary hyperalgesia and is frequency dependent such that high frequency TENS produces approximately a 30% reduction in hyperalgesia whereas low frequency TENS has no effect. Both high and low frequency TENS completely reduce secondary hyperalgesia by activation of mu and delta- opioid receptors in the spinal cord and rostral-ventral medulla suggesting an opiate mediated analgesia. Clonidine in combination with opiates produces a synergistic interaction such that there is a potentiated reduction in hyperalgesia. ⋯ The ED50s for heat and mechanical hyperalgesia following low frequency TENS with clonidine were 0.002 and 0.2 mg/kg, respectively and those following high frequency TENS with clonidine were 0.005 and 0.15 mg/kg, respectively. Thus, combined use of clonidine and TENS enhances the reduction in analgesia produced by TENS and enhances the potency of clonidine. It would thus be expected that one would reduce the side effects of clonidine and enhance analgesic efficacy with combinations of pharmaceutical and non-pharmaceutical treatments.
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Randomized Controlled Trial Clinical Trial
Experimental incision-induced pain in human skin: effects of systemic lidocaine on flare formation and hyperalgesia.
In order to try to gain a better understanding of the mechanisms of post-operative pain, this study was designed to psychophysically determine physiological and pharmacological characteristics of experimental pain induced by a 4-mm-long incision through the skin, fascia and muscle in the volar forearm of humans. In experiment 1, the subjects (n=8) were administered lidocaine systemically (a bolus injection of 2mg/kg for a period of 5 min followed by an intravenous infusion of 2mg/kg/h for another 40 min), and then the incision was made. In experiment 2, cumulative doses of lidocaine (0.5-2mg/kg) were systemically injected in the subjects (n=8) 30 min after the incision had been made, when primary and secondary hyperalgesia had fully developed. ⋯ Pre-traumatic treatment with lidocaine would temporarily stabilize the sensitized nerves in the injured area, but the nerves would be sensitized after completion of the administration. Post-traumatic treatment with lidocaine reduced primary and secondary hyperalgesia that had fully developed. However, the finding that the suppressive effect of lidocaine on secondary hyperalgesia was temporary suggests that the development and maintenance of secondary hyperalgesia are caused by different mechanisms.
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Randomized Controlled Trial Clinical Trial
Tailored cognitive-behavioral therapy in early rheumatoid arthritis for patients at risk: a randomized controlled trial.
Recent developments in chronic pain research suggest that effectiveness of cognitive-behavioral therapy (CBT) may be optimized when applying early, customized treatments to patients at risk. For this purpose, a randomized, controlled trial with tailor-made treatment modules was conducted among patients with relatively early rheumatoid arthritis (RA disease duration of <8 years), who had been screened for psychosocial risk profiles. All participants received standard medical care from a rheumatologist and rheumatology nurse consultant. ⋯ Specifically, fatigue and depression were significantly reduced at post-treatment and at the 6-month follow-up in the CBT condition in comparison to the control condition, while perceived support increased at follow-up assessment. In addition, helplessness decreased at post-treatment and follow-up assessment, active coping with stress increased at post-treatment, and compliance with medication increased at follow-up assessment in the CBT condition in comparison to the control condition. Results indicate the effectiveness of tailor-made CBT for patients at risk in relatively early RA, and supply preliminary support for the idea that customizing treatments to patient characteristics may be a way to optimize CBT effectiveness in RA patients.