Pain
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In previous studies that examined the impact of attention biases (ABs) on later pain outcomes, reaction times (RTs) in response to brief stimulus presentations had been used as measures of attention. Consequently, little is known about effects of ABs assessed during presentations of cues or biases in prolonged attention towards pain stimuli as influences on subsequent functioning. ⋯ However, participants who gazed at injury images for longer durations during I-N trials reported significantly more pain and interference at follow-up than did peers who gazed at injury images for less time, even after the impact of other significant baseline predictors had been controlled. In sum, results provided initial evidence for gaze biases reflecting prolonged vigilance towards pain-related information as a potential risk factor for relative elevations in pain and interference from chronic pain.
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Nerve growth factor (NGF) and its receptors TrkA and p75 play a key role in the development and function of peripheral nociceptive neurons. Here, we describe novel technology to selectively photoablate TrkA-positive nociceptors through delivery of a phototoxic agent coupled to an engineered NGF ligand and subsequent near-infrared illumination. We demonstrate that this approach allows for on demand and localized reversal of pain behaviors in mouse models of acute, inflammatory, neuropathic, and joint pain. ⋯ Similarly, in models of inflammatory, osteoarthritic, and neuropathic pain, mechanical hypersensitivity was abolished for 3 weeks after a single treatment regime. We demonstrate that this loss of pain behavior coincides with the retraction of neurons from the skin which then reinnervate the epidermis after 3 weeks corresponding with the return of mechanical hypersensitivity. Thus NGF-mediated photoablation is a minimally invasive approach to reversibly silence nociceptor input from the periphery, and control pain and hypersensitivity to mechanical stimuli.
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Randomized Controlled Trial Multicenter Study
Onset of action of naldemedine in the treatment of opioid-induced constipation in patients with chronic noncancer pain: results from 2 randomized, placebocontrolled, phase 3 trials.
Opioid-induced constipation (OIC) is a common side effect of chronic opioid therapy. Previously, naldemedine, a peripherally acting μ-opioid receptor antagonist demonstrated efficacy in the treatment of OIC. In this exploratory analysis, the onset of action of naldemedine was evaluated in 2 identically designed phase 3, randomized, placebo-controlled trials. ⋯ Treatment-emergent adverse events were reported most frequently on day 1, followed by a decrease from days 2 to 7. Naldemedine had a timely onset of effect, and gastrointestinal adverse events largely resolved within the first week. These findings should assist clinicians counseling patients with chronic noncancer pain on expectations when initiating naldemedine for OIC.
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Clinical Trial
Recovery of physical activity after cesarean delivery and its relationship with pain.
Pain and physical activity are tightly intertwined. Although their relationship has been explored in chronic pain conditions, we know little about the pattern of recovery in activity and its short- and long-term relationship with pain after surgery. We recruited 103 women undergoing elective cesarean delivery and acquired daily pain assessments and hourly steps in 98 of them for 2 months after surgery. ⋯ A patient's previous experience of pain was not associated with current activity as well as current activity was not associated with future pain scores. These data, although limited by the study of a single operation in a unique social circumstance with low risk of chronic postsurgical pain, demonstrate feasibility of measuring hourly activity for 2 months after surgery. Recovery from pain and inactivity are tightly correlated, and the negative relationship between within-day pain and activity without interday carryover relationships is in stark contrast to findings in chronic pain conditions.