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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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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This study examined the influence of patients' likability on pain estimations made by observers. Patients' likability was manipulated by means of an evaluative conditioning procedure: pictures of patients were combined with either positive, neutral, or negative personal traits. Next, videos of the patients were presented to 40 observers who rated the pain. ⋯ The effect on pain estimations was only found with regard to patients expressing high-intensity pain. There was no effect on response bias (i.e., the overall tendency to indicate pain). These findings suggest that we take the pain of patients we do not like less seriously than the pain of patients we like.