Pain
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For reasons unknown, temporomandibular disorder (TMD) can manifest as localized pain or in conjunction with widespread pain. We evaluated relationships between cytokines and TMD without or with widespread palpation tenderness (TMD-WPT or TMD+WPT, respectively) at protein, transcription factory activity, and gene levels. Additionally, we evaluated the relationship between cytokines and intermediate phenotypes characteristic of TMD and WPT. ⋯ Interactions were observed between TGFβ1 and IL-8 SNPs: an additional copy of the TGFβ1 rs2241719 minor T allele was associated with twice the odds of TMD+WPT among individuals homozygous for the IL-8 rs4073 major A allele, and half the odds of TMD+WPT among individuals heterozygous for rs4073. These results demonstrate how pro- and antiinflammatory cytokines contribute to the pathophysiology of TMD and WPT in genetically susceptible people. Furthermore, they identify MCP-1, IL-1ra, IL-8, and TGFβ1 as potential diagnostic markers and therapeutic targets for pain in patients with TMD.
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We report the first nationwide survey of the impact of neuropathic pain, as opposed to nonneuropathic pain, on quality of life and health care utilization in the French general population. A postal questionnaire was sent to a representative sample of 4554 respondents from an initial nationwide survey of 30,155 subjects with or without chronic pain. It included pain characteristics (Neuropathic Pain Symptom Inventory, DN4), quality of life (Medical Outcomes Short Form 12, SF-12), sleep, anxiety/depressive symptoms (Hospital Anxiety and Depression Scale) and health care utilization. ⋯ They also made greater use of health care facilities, particularly as concerned neurological treatments and visits to neurologists (21% vs 9%; P<.01). Multivariate analyses showed that the neuropathic characteristics of pain made an independent contribution to quality-of-life impairment (P<.0001 and P=.0005 for the physical and mental scores of the SF-12 respectively). Our study indicates that the disease burden of chronic pain depends on the nature of the pain, independently of its intensity and duration.
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Research has demonstrated that health care practitioners' adherence to guidelines for managing low back pain (LBP) remain suboptimal in recommending work absence, but specific beliefs about their role in maintaining patients at work have not been adequately researched. We examined private musculoskeletal practitioners' (chiropractors, osteopaths, and physiotherapists) beliefs and reported clinical behaviours in reference to patients' work. A cross-sectional postal questionnaire of 900 musculoskeletal practitioners included the Attitudes to Back pain in musculoskeletal practitioners questionnaires, reported frequency of four work-related behaviours, and a new measure of practitioners' work-related beliefs. ⋯ Our study confirms that, in contrast to current guidelines, many practitioners believe that LBP necessitates work absence. Overall, practitioners perceived their role in returning patients to work as limited, and believed that direct contact with employers was beyond their remit. In the UK, physiotherapists appear to be better placed to liaise with work in terms of both their beliefs and activities.
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Spatial summation (SS) and spatial discrimination (SD) are essential for pain perception. In the cold-pain sensation, these processes have hardly been studied. Our aim was to study the SS and SD of cold pain, as well as the SS of cold-pain threshold (CPT) in hairy and glabrous skin. ⋯ CPT was significantly higher in hairy than glabrous skin, but the amount of SS of CPT was similar in the 2 skin types. Noxious cold-evoked thermal qualities were more common in the glabrous than the hairy skin. In conclusion: (1) SS and SD of cold pain are reciprocal; (2) whereas cold pain can summate over large distances, the SD of cold pain is poor; (3) SS of cold pain does not exist between contralateral body sides, however, inhibition occurs; (4) SS is independent of skin type and sensitivity to cold pain; (5) differences in pain quality between hairy and glabrous skin may reflect innervation differences.
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Persistent pain after resolution of clinically appreciable signs of arthritis poses a therapeutic challenge, and immunosuppressive therapies do not meet this medical need. To investigate this conversion to persistent pain, we utilized the K/BxN serum transfer arthritis model, which has persistent mechanical hypersensitivity despite the resolution of visible inflammation. Toll-like receptor (TLR) 4 has been implicated as a potential therapeutic target in neuropathic and other pain models. ⋯ WT arthritic mice had reduced spinal levels of the anti-inflammatory prostaglandin 15-deoxy-Δ(12,14)-PGJ(2) (15d-PGJ(2)) on day 6, compared to IT LPS-RS-treated mice. Direct IT application of 15d-PGJ(2) (0.5 μg) on day 6 improved mechanical hypersensitivity in arthritic mice within 15 min. Hence, TLR4 signaling altered spinal bioactive lipid profiles in the serum transfer model and played a critical role in the transition from acute to chronic postinflammatory mechanical hypersensitivity.