Pain
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Controlled Clinical Trial
Structural abnormalities of the trigeminal root revealed by diffusion tensor imaging in patients with trigeminal neuralgia caused by neurovascular compression: a prospective, double-blind, controlled study.
Because diffusion tensor imaging (DTI) is able to assess tissue integrity, we used diffusion to detect abnormalities in trigeminal nerves (TGN) in patients with trigeminal neuralgia (TN) caused by neurovascular compression (NVC). We also studied anatomical TGN parameters (cross-sectional area [CSA] and volume [V]). Using DTI sequencing in a 3-T magnetic resonance imaging (MRI) scanner, we measured the fraction of anisotropy (FA) and the apparent diffusion coefficient (ADC) of TGN in 10 patients selected as candidates to have microvascular decompression (MVD) for TN, and 6 normal control subjects. ⋯ The Spearman correlation coefficient showed a strong negative correlation between increase in ADC and loss of V (r=-0.7173) and loss of CSA (r=-0.7416) in affected nerves. DTI revealed alteration in the FA and ADC values of the affected TGN. These alterations were correlated with atrophic changes in patients with TN caused by NVC.
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Parent perceptions of and responses to pain have been identified as important factors in understanding pain-related disability among children and adolescents with chronic pain. The ability to accept chronic pain rather than focus on ways to avoid or control it has been linked to positive outcomes in chronic pain research. To examine parent beliefs about child acceptance of pain, the Chronic Pain Acceptance Questionnaire, parent report (CPAQ-P), was developed and administered to 195 parents of children with persistent pain evaluated in a multidisciplinary pain clinic. ⋯ For construct validity, parent beliefs about child acceptance were negatively correlated with parent pain catastrophizing and parent fear of pain. Greater acceptance was also negatively associated with protective parent responses to pain. These results support the CPAQ-P as a promising measure for assessing parent beliefs about child acceptance of pain and reinforce the importance of the social context and parental influence on child functioning.
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Randomized Controlled Trial
Randomized trial of a DVD intervention to improve readiness to self-manage joint pain.
A DVD (digital video disk) intervention to increase readiness to self-manage joint pain secondary to hemophilia was informed by a 2-phase, motivational-volitional model of readiness to self-manage pain, and featured the personal experiences of individuals with hemophilia. The DVD was evaluated in a randomized controlled trial in which 108 men with hemophilia completed measures of readiness to self-manage pain (Pain Stages of Change Questionnaire) before and 6 months after receiving the DVD plus information booklet (n=57) or just the booklet (n=51). The effect of the DVD was assessed by comparing changes in Pain Stages of Change Questionnaire scores (precontemplation, contemplation, and action/maintenance) between groups. ⋯ Significant use×time effects showed that benefits in terms of contemplation and action/maintenance were restricted to those who used the interventions at least once. The results show that low-intensity interventions in DVD format can improve the motivational impact of written information, and could be used to help prepare people with chronic pain for more intensive self-management interventions. The findings are consistent with a 2-phase, motivational-volitional model of pain self-management, and provide the first insights to our knowledge of readiness to self-manage pain in hemophilia.
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Endothelin-1 is a vasoactive peptide that activates both the endothelin A (ET(A)) and endothelin B (ET(B)) receptors, and is secreted in high concentrations in many different cancer environments. Although ET(A) receptor activation has an established nociceptive effect in cancer models, the role of ET(B) receptors on cancer pain is controversial. EDNRB, the gene encoding the ET(B) receptor, has been shown to be hypermethylated and transcriptionally silenced in many different cancers. ⋯ ET(B) mRNA expression is reduced in the human oral squamous cell carcinoma lesions as a consequence of EDNRB hypermethylation. Using a mouse cancer pain model, we show that ET(B) receptor re-expression attenuates cancer-induced pain. These findings identify EDNRB methylation as a novel regulatory mechanism in cancer-induced pain and suggest that demethylation therapy targeted at the cancer microenvironment has the potential to thwart pain-producing mechanisms at the source, thus freeing patients of systemic analgesic toxicity.
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Fear of pain (FOP) and its effect on placebo analgesia was investigated. It was hypothesized that FOP should interfere with placebo-mediated pain inhibition and result in weaker placebo responding in pain intensity, pain unpleasantness, stress, and event-related potentials to contact heat pain. Thirty-three subjects participated in a balanced 2 condition (natural history, placebo)×3 test (pretest, posttest 1, posttest 2) within-subject design, tested on 2 separate days. ⋯ FOP was related to reduced placebo responding on P2 amplitude, whereas placebo responding on N2 amplitude was unaffected by FOP. Higher placebo responses on N2 and P2 amplitudes were both related to higher placebo analgesic magnitude in pain unpleasantness. In conclusion, increased FOP was found to reduce subjective and electrophysiological placebo analgesic responses.