Pain
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Randomized Controlled Trial Comparative Study
Cancer pain and its relationship to systemic inflammation: an exploratory study.
Pain is the commonest symptom in cancer patients, whereas inflammation is implicated in cancer development and progression. The relationship between pain and inflammation in cancer is therefore of interest; however, it is challenging to examine because multiple factors may affect these variables. This study assessed the relationship between cancer pain and systemic inflammation using a retrospective analysis of 2 clinical trial datasets of patients with cancer cachexia. ⋯ Many factors can affect pain and inflammation in cancer, demonstrating that any relationship that exists between pain and inflammation is of interest. This is in keeping with work showing this relationship in nonmalignant pain. Studies targeting inflammation and assessing its effect on pain in cancer would be an important step in the research agenda.
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Randomized Controlled Trial Comparative Study
Neuropharmacological basis of rTMS-induced analgesia: the role of endogenous opioids.
We investigated the role of endogenous opioid systems in the analgesic effects induced by repetitive transcranial magnetic stimulation (rTMS). We compared the analgesic effects of motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC) stimulation before and after naloxone or placebo treatment, in a randomized, double-blind crossover design, in healthy volunteers. Three groups of 12 volunteers were selected at random and given active stimulation (frequency 10Hz, at 80% motor threshold intensity, 1500 pulses per session) of the right M1, active stimulation of the right DLPFC, or sham stimulation, during two experimental sessions 2 weeks apart. ⋯ This study demonstrates, for the first time, the involvement of endogenous opioid systems in rTMS-induced analgesia. The differential effects of naloxone on M1 and DLPFC stimulation suggest that the analgesic effects induced by the stimulation of these 2 cortical sites are mediated by different mechanisms. Endogenous opioids are shown to be involved in the analgesic effects of repetitive transcranial magnetic stimulation of the motor cortex.
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Randomized Controlled Trial Comparative Study
Effectiveness of small daily amounts of progressive resistance training for frequent neck/shoulder pain: randomised controlled trial.
Regular physical exercise is a cornerstone in rehabilitation programs, but adherence to comprehensive exercise remains low. This study determined the effectiveness of small daily amounts of progressive resistance training for relieving neck/shoulder pain in healthy adults with frequent symptoms; 174 women and 24 men working at least 30 h per week and with frequent neck/shoulder pain were randomly assigned to resistance training with elastic tubing for 2 or 12 minutes per day 5 times per week, or weekly information on general health (control group). Primary outcomes were changes in intensity of neck/shoulder pain (scale 0 to 10), examiner-verified tenderness of the neck/shoulder muscles (total tenderness score of 0 to 32), and isometric muscle strength at 10 weeks. Compared with the control group, neck/shoulder pain and tenderness, respectively, decreased 1.4 points (95% confidence interval -2.0 to -0.7, p<0.0001) and 4.2 points (95% confidence interval -5.7 to -2.7, p<0.0001) in the 2-minute group and 1.9 points (95% confidence interval -2.5 to -1.2, p<0.0001) and 4.4 points (95% confidence interval -5.9 to -2.9, p<0.0001) in the 12-minute group. Compared with the control group, muscle strength increased 2.0 Nm (95% confidence interval 0.5 to 3.5Nm, p=0.01) in the 2-minute group and 1.7Nm (95% confidence interval 0.2 to 3.3 Nm, p=0.02) in the 12-minute group. In conclusion, as little as 2 minutes of daily progressive resistance training for 10 weeks results in clinically relevant reductions of pain and tenderness in healthy adults with frequent neck/shoulder symptoms.
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Randomized Controlled Trial
Duloxetine in patients with central neuropathic pain caused by spinal cord injury or stroke: a randomized, double-blind, placebo-controlled trial.
The mechanisms underlying central neuropathic pain are poorly understood. Pain inhibitory mechanisms including sertononergic and norepinephrine systems may be dysfunctional. In this randomized, double-blinded, placebo-controlled trial we evaluated the effects of duloxetine on pain relief (spontaneous pain and evoked pain), tolerability, health status, and quality of life in patients with central pain related to cerebrovascular lesions or spinal cord lesions. ⋯ No significant differences were observed in the other domains of the SF36, the Pain Disability Index, and the EQ-5D. While this trial showed no significant effect on pain intensity, duloxetine revealed a biologic effect. It would be worthwhile to suspend our judgement and to perform more studies to evaluate the role of duloxetine in modulation of the symptoms of central neuropathic pain.
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Randomized Controlled Trial
Treating pain with pain: supraspinal mechanisms of endogenous analgesia elicited by heterotopic noxious conditioning stimulation.
While being exposed to an intensive tonic pain stimulus at one area of the body, another phasic pain stimulus applied to a remote site is perceived as less painful. The neurophysiological basis for this "pain inhibits pain" phenomenon has been presumed to be an activation of the spino-bulbo-spinal mechanism termed "diffuse noxious inhibitory controls." However, several additional mechanisms such as an activation of the descending pain control system may contribute to this observation. Here we investigated the underlying supraspinal mechanisms of "heterotopic noxious conditioning stimulations" (HNCS), representing this specific experimental constellation. ⋯ These effects were in part reversed by naloxone, speaking for the contribution of endogenous opioid neurotransmission to this mechanism. Taken together, these results demonstrate a substantial contribution of higher-order brain regions to the phenomenon of hypoalgesia during HNCS. Functional magnetic resonance imaging shows how the human brain is involved in heterotopic noxious conditioning and reveals active supraspinal pain modulatory mechanisms during dual pain stimulation.