European journal of pain : EJP
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A significant number of patients with Gaucher disease (GD) suffer from chronic or acute pain that reduces their quality of life. A mutation in lysosomal enzyme β-glucosidase (GCase) leads to an accumulation of glucocerebroside in the macrophage-lineage cells, causing the development of clinical symptoms. Novel studies have revealed that ambroxol (trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanol), the well-known mucolytic drug, acts as a chaperone for the mutant, misfolded enzyme. ⋯ However, when the dose was increased up to 450mg/d, the intensity of pain diminished and subsided within the following months. Two of three attempts to reduce the dose of ambroxol resulted in a pain relapse within a week, which subsided after resetting the previous, higher dose. This observation of the effects of ambroxol in a GD patient is worth considering for other GD patients with chronic pain.
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The dorsal root (DRG) and trigeminal (TG) ganglia contain cell bodies of sensory neurons of spinal and trigeminal systems, respectively. They are homologs of each other; however, differences in how the two systems respond to injury exist. Trigeminal nerve injuries rarely result in chronic neuropathic pain (NP). To date, no genes involved in the differential response to nerve injury between the two systems have been identified. We examined transcriptional changes involved in the development of trigeminal and spinal NP. ⋯ We present distinct transcriptional alterations in the TG and DRG that may contribute to differences observed in the corresponding mononeuropathies. Since the trigeminal system seems more resistant to developing NP following trauma our findings lay ground for future research to detect genes and pathways that may act in a protective or facilitatory manner. These may be novel and important therapeutic targets.
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Review Meta Analysis
Effectiveness of motor imagery and action observation training on musculoskeletal pain intensity: A systematic review and meta-analysis.
Movement representation techniques such as motor imagery (MI) and action observation (AO) could play an important role in the field of rehabilitation of patients with musculoskeletal pain; however, the effects of these tools on clinical pain remain unclear. Our objective is therefore to develop a systematic review and meta-analysis of the effects of MI and AO regarding the pain intensity on patients with musculoskeletal pain. ⋯ Movement representation techniques in combination with usual care are capable of producing a decrease in pain intensity compared with conventional treatment, in both post-surgical and chronic pain. However, the very low-quality evidence found regarding these techniques showed that more research is needed for their application in a clinical context.
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Randomized Controlled Trial
A randomised, double-blind, crossover, dose ranging study to determine the optimal dose of oral opioid to treat breakthrough pain for patients with advanced cancer already established on regular opioids.
Pain in people with advanced cancer is prevalent. When a stable dose of opioids is established, people still experience episodic breakthrough pain for which dosing of an immediate release opioid is usually a proportion of the total daily dose. ⋯ Despite the widespread use of immediate release morphine solution for breakthrough cancer pain, the ideal dose derived from background dose has not been determined in an adequately powered randomized, double-blind, crossover, dose ranging study. This study tested three dose levels in people with advanced cancer. Given no differences in time to onset, level of analgesia achieved, nor side effects, the lowest dose tested (1/12th of the daily dose) should be used.
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Placebo effects are considered to be learning phenomena. There is a growing body of evidence supporting the role of both classical conditioning and observational learning in the induction of placebo effects. However, the third basic learning process, operant conditioning, was not considered as a mechanism of placebo effects until very recently. Unlike classically conditioned responses, which are induced by stimuli that precede the behaviour, operant behaviours are shaped and maintained by their consequences. Thus, placebo effects may not only result from pairing an active intervention with the stimuli that accompany its administration (placebo) but also positive (e.g. the ability to perform a desired activity) or negative reinforcement (e.g. pain relief) of placebo administration may increase the frequency of taking placebos in the future. The paper reviews the evidence supporting the idea of operant conditioning as a mechanism of placebo effects and discusses it in the context of the general principles of operant conditioning, the operant conditioning account of pain modulation and research findings on the role of operant conditioning in pain modulation. ⋯ The operant conditioning account of placebo effects is discussed from the theoretical perspective of the general principles of operant conditioning and the operant conditioning account of pain modulation. The paper identifies seven lines of research on the role of operant conditioning in producing placebo effects, and highlights the practical implications of the operant conditioning account of placebo effects both for routine clinical practice and the placebo arms of randomized controlled trials.