European journal of pain : EJP
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Electrical low-frequency stimulation (LFS) of nociceptive skin afferents reliably induces long-term depression (LTD) of pain. Recent experiments have assessed the effects of LTD on pain perception by using a simple one-dimensional rating scale. The psychophysical study investigated the impact of noxious LFS on the sensory and affective aspects of pain perception by multidimensional rating scales. ⋯ Both components decrease during noxious, conditioning LFS and remain depressed for at least one hour. Reduction of sharp pain points to Adelta fiber mediated LTD. These results stress the analgesic potency of LTD and its possible impact on future therapy in chronic pain.
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Bortezomib is a proteasome inhibitor showing strong antitumor activity against many tumors, primarily multiple myeloma. Bortezomib-induced neuropathic pain is the main side effect and the dose-limiting factor of the drug in clinical practice. In order to obtain a pre-clinical model to reproduce the characteristic pain symptoms in bortezomib-treated patients, we developed an animal model of bortezomib-induced nociceptive sensory neuropathy. ⋯ The pathological examination revealed a dose-dependent axonopathy of the unmyelinated fibers in nerves of treated animals. No pathological alteration in most of DRG satellite cells and neurons was observed. Therefore, this animal model may be useful for studying the neurotoxicity and pain onset mechanisms related to bortezomib treatment.
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Randomized Controlled Trial
Effects of low-dose intranasal (S)-ketamine in patients with neuropathic pain.
NMDA receptors are involved in the development and maintenance of neuropathic pain. We evaluated the efficacy and safety of intranasal (S)-ketamine, one of the most potent clinically available NMDA receptor antagonists. ⋯ Intranasal administration of low dose (S)-ketamine rapidly induces adequate plasma concentrations of (S)-ketamine and subsequently of its metabolite (S)-norketamine. The time course of analgesia correlated with plasma concentrations.
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Randomized Controlled Trial
The role of current mood and stop rules on physical task performance: an experimental investigation in patients with work-related upper extremity pain.
Patients with work-related upper extremity pain (WRUED) experience disability in daily life activities. The factors that influence levels of disability are still unclear. Both excessive avoidance and persistence have been suggested, but the affective and motivational processes that underlie these behaviours have not been scrutinized. ⋯ Results showed that physical task performance was predicted by pain-related fear, current mood, stop rule. However, the predicted moodxstop rule interaction was not found, and there was no influence of gender, pain severity, and pain catastrophizing on task performance. The findings suggest that not only pain-related fear, but current mood and goal context factors independently affect physical performance in patients with WRUED.
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Comparative Study
A comparison of anatomical pain sites from a tertiary care sample: evidence of disconnect between functional and perceived disability specific to lower back pain.
Heterogeneity has been identified within chronic musculoskeletal pain (CMP) patient samples; however, investigations have typically focused on psychological constructs or coping (e.g., pain-related anxiety, catastrophizing) in this regard. Furthermore, studies to date have included either samples presenting with a specific anatomical site (e.g., only lower back pain) or a mix of anatomical sites (e.g., lower back, shoulder, or leg pain) as the primary pain complaint, without making comparisons based on the anatomical site of reported pain. For example, patients with chronic lower back pain (CLBP) may differ from those with chronic upper or lower extremity pain (ULEP) in presentation, recovery trajectory, and psychological variables. ⋯ Specifically, CLBP patients reported increasing perceived disability despite improvements in functional deficit, whereas ULEP patients did not. These findings suggest a disconnect between perceived disability and function that may be specific to lower back pain. Implications and directions for future research are discussed.