Pain
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Although preclinical studies generally report robust antinociceptive effects of cannabinoids in rodent persistent pain models, randomized controlled trials in chronic pain patients report limited pain relief from cannabis/cannabinoids. Differences between animal and human studies that may contribute to these discrepant findings include route of cannabis/cannabinoid administration, type of cannabis/cannabinoid, and how pain is measured. To address these factors, rats with complete Freund adjuvant (CFA)-induced hind paw inflammation were exposed acutely or repeatedly to vaporized cannabis extract that was either tetrahydrocannabinol (THC) or cannabidiol (CBD)dominant. ⋯ Acute exposure to vaporized CBD-dominant cannabis extract (200 mg/mL) did not produce any effects in either sex; repeated exposure to this extract (100, 200, or 400 mg/mL) decreased mechanical allodynia in male rats only. Sex differences (or lack thereof) in the effects of vaporized cannabis extracts were not explained by sex differences in plasma levels of THC, CBD, or their major metabolites. These results suggest that although vaporized THC-dominant extract is likely to be modestly effective against inflammatory pain in both male and female rats, tolerance may develop, and the CBD-dominant extract may be effective only in male rats.
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Randomized Controlled Trial
Adjunctive virtual reality pain relief after traumatic injury: a proof-of-concept within-person randomized trial.
In this study, we hypothesized that immersive virtual reality (VR) environments may reduce pain in patients with acute traumatic injuries, including traumatic brain injuries. We performed a randomized within-subject study in patients hospitalized with acute traumatic injuries, including traumatic brain injury with moderate pain (numeric pain score ≥3 of 10). We compared 3 conditions: (1) an immersive VR environment (VR Blu), (2) a content control with the identical environment delivered through nonimmersive tablet computer (Tablet Blu), and (3) a second control composed of donning VR headgear without content to control for placebo effects and sensory deprivation (VR Blank). ⋯ VR Blu was perceived as most effective by patients for pain reduction (F 2,66.84 = 16.28, P < 0.001), and changes in measures of parasympathetic activity including heart rate variability (F 2,55.511 = 7.87, P < 0.001) and pupillary maximum constriction velocity (F 2,61.41 = 3.50, 1-tailed P = 0.038) echoed these effects. There were no effects on opioid usage. These findings outlined a potential clinical benefit for mollifying pain related to traumatic injuries.
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Randomized Controlled Trial
Conflicts hurt: social stress predicts elevated pain and sadness after mild inflammatory increases.
Individuals respond differently to inflammation. Pain, sadness, and fatigue are common correlates of inflammation among breast cancer survivors. Stress may predict response intensity. ⋯ At each visit, a trained experimenter administered the Daily Inventory of Stressful Events to assess social and nonsocial stress exposure within the past 24 hours. After statistical adjustment for relevant demographic and behavioral covariates, the most consistent results were that survivors who reported more chronic social stress reported more pain and sadness in response to IL-1Ra increases. Frequent and ongoing social stress may sensitize the nervous system to the effects of inflammation, with potential implications for chronic pain and depression risk among breast cancer survivors.
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Chemotherapy-induced peripheral neuropathic pain (CIPNP) is an adverse effect observed in up to 80% of patients of cancer on treatment with cytostatic drugs including paclitaxel and oxaliplatin. Chemotherapy-induced peripheral neuropathic pain can be so severe that it limits dose and choice of chemotherapy and has significant negative consequences on the quality of life of survivors. Current treatment options for CIPNP are limited and unsatisfactory. ⋯ In addition, the levels of protein ERK, a marker for neuronal activity, were significantly reduced in dorsal root ganglion neurons derived from TRPM3 deficient mice compared with control after oxaliplatin administration. Moreover, intraperitoneal injection of a TRPM3 antagonist, isosakuranetin, effectively reduced the oxaliplatin-induced pain behavior in response to cold and mechanical stimulation in mice with an acute form of oxaliplatin-induced peripheral neuropathy. In summary, TRPM3 represents a potential new target for the treatment of neuropathic pain in patients undergoing chemotherapy.
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Current automated pain assessment methods only focus on infants or youth. They are less practical because the children who suffer from postoperative pain in clinical scenarios are in a wider range of ages. In this article, we present a large-scale Clinical Pain Expression of Children (CPEC) dataset for postoperative pain assessment in children. ⋯ The CPANN achieves 82.1% accuracy and 73.9% macro-F1 score on the testing set of CPEC. The CPANN is faster, more convenient, and more objective compared with using pain scales according to the specific type of pain or children's condition. This study demonstrates the effectiveness of deep learning-based method for automated pain assessment in children.