Articles: hyperalgesia.
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We have previously shown that intradermal injection of high-molecular-weight hyaluronan (500-1200 kDa) produces localized antihyperalgesia in preclinical models of inflammatory and neuropathic pain. In the present experiments, we studied the therapeutic effect of topical hyaluronan, when combined with each of 3 transdermal drug delivery enhancers (dimethyl sulfoxide [DMSO], protamine or terpene), in preclinical models of inflammatory and neuropathic pain. Topical application of 500 to 1200 kDa hyaluronan (the molecular weight range used in our previous studies employing intradermal administration), dissolved in 75% DMSO in saline, markedly reduced prostaglandin E 2 (PGE 2 ) hyperalgesia, in male and female rats. ⋯ The topical administration of a combination of hyaluronan with 2 other transdermal drug delivery enhancers, protamine and terpene, also attenuated CIPN hyperalgesia, an effect that was more prolonged than with DMSO vehicle. Repeated administration of topical hyaluronan prolonged the duration of antihyperalgesia. Our results support the use of topical hyaluronan, combined with chemically diverse nontoxic skin penetration enhancers, to induce marked antihyperalgesia in preclinical models of inflammatory and neuropathic pain.
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Opioids are metabolised by enzymes the activities of which vary with the circadian rhythm. We examined whether opioid infusions administered at different times of the day produce varying degrees of opioid-induced hyperalgesia (OIH) in animal experiments and clinical studies. ⋯ NCT05234697.
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Observational Study
Pre- and post-headache phases of migraine: multi-country results from the CaMEO - International Study.
Individuals with migraine frequently experience pre- and post-headache symptoms. This analysis aimed to characterize the relative frequency and burden of pre- and post-headache symptoms in people with migraine using data collected through the Chronic Migraine Epidemiology and Outcomes - International Study. ⋯ Pre- and post-headache phases of migraine are common, carry unrecognized burden, and may be a target for treatment.
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Observing someone experience pain relief or exacerbation after an intervention may induce placebo hypoalgesia or nocebo hyperalgesia. Understanding the factors that contribute to these effects could help in the development of strategies for optimizing treatment of chronic pain conditions. We systematically reviewed and meta-analyzed the literature on placebo hypoalgesia and nocebo hyperalgesia induced by observational learning (OL). ⋯ Overall, the meta-analysis demonstrates that OL can shape placebo hypoalgesia and nocebo hyperalgesia. More research is needed to identify predictors of these effects and to study them in clinical populations. In the future, OL could be an important tool to help maximize placebo hypoalgesia in clinical settings.
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Observational Study
Motor Imagery and Pain Processing in Patients with Entrapment Neuropathies: A Cross-Sectional Study.
(1) To assess the ability to generate both kinesthetic and visual motor imagery in participants with carpal tunnel syndrome (CTS), compared with asymptomatic participants. (2) To assess the influence of psychophysiological and functional variables in the motor imagery process. ⋯ CTS patients have greater difficulty generating motor images than asymptomatic individuals. Patients also spend more time during mental tasks. CTS patients present a relationship between temporal summation and the capacity to generate kinesthetic images. In addition, the CST patients presented a correlation between chronometry mental tasking and mechanical hyperalgesia.