Pain
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In many countries timely access to care is a growing problem. As medical costs escalate health care resources must be prioritized. In this context there is an increasing need for benchmarks and best practices in wait-time management. ⋯ It was concluded that wait-times for chronic pain treatment of 6 months or longer are medically unacceptable. Further study is necessary to determine at what stage the deterioration begins from the onset of pain to treatment and the impact of waiting on treatment outcomes. Most important is the need to improve access to appropriate care for patients with chronic pain, an escalating public health care problem with significant human and economic costs.
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Comparative Study
Individual differences in pain sensitivity: genetic and environmental contributions.
Large individual differences in pain sensitivity present a challenge for medical diagnosis and may be of importance for the development of chronic pain. Variance in pain sensitivity is partially mediated by genetic factors, but the extent of this contribution is uncertain. We examined cold-pressor pain and contact heat pain in 53 identical (MZ) and 39 fraternal (DZ) twin pairs, and 4 single twins to determine the heritability of the two phenotypes, and the extent to which the same genetic and environmental factors affect both pain modalities. ⋯ These findings demonstrate that cold-pressor pain and contact heat pain are mainly distinct phenomena from both a genetic and an environmental standpoint. This may partly explain disparate results in genetic association studies and argues for caution in generalizing genetic findings from one pain modality to another. It also indicates that differences in pain scale usage account for a minor portion of the variance, providing strong support for the validity of subjective pain ratings as measures of experienced pain.
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Comparative Study
Population-based cohort study of incident and persistent arm pain: role of mental health, self-rated health and health beliefs.
To investigate whether somatising tendency, low mood and poor self-rated health (SRH) predict incident arm pain, and whether these factors and beliefs about causation and prognosis predict symptom persistence, we conducted an 18-month postal follow-up in 1798 working-aged subjects, sampled from the registers of five British general practices. At baseline questions were asked about pain in the arm (lasting >or=1day in the prior 12months), mental health (Short-Form 36 (SF-36MH)), somatising tendency (the Brief Symptom Inventory (BSI)), SRH, and beliefs about causation and prognosis. At follow-up we asked about arm pain in the last four weeks, and whether it had been present on >or=14days. ⋯ Even stronger associations were found for arm pain on >or=14days. Persistent pain was significantly more common among those who attributed their pain to work or stress, and in those who expected symptoms still to be a problem in 12months. Thus, SRH and mental health indices were strong predictors of incident and persistent arm pain in adults from the community, while persistence was also predicted by beliefs about causation and prognosis.
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Comparative Study
Enhanced LTP of primary afferent neurotransmission in AMPA receptor GluR2-deficient mice.
Ca(2+)-permeable-AMPA receptors (AMPARs) are expressed in the superficial dorsal horn (SDH, laminae I/II) of the spinal cord, the area involved in transmission and modulation of sensory information, including nociception. A possible role of Ca(2+)-permeable-AMPARs in synaptic strengthening has been suggested in postnatal DH cultures, but their role in the long-lasting activity-dependent synaptic plasticity of primary afferent neurotransmission in the adult mouse SDH has not been investigated. In the present study the role of Ca(2+)-permeable-AMPARs in the regulation of long-lasting synaptic plasticity, specifically long-term potentiation (LTP) and long-term depression (LTD) in the SDH, was investigated using mice deficient in AMPAR GluR2 subunit. ⋯ The LTP could be induced in the presence of the NMDA receptor antagonist d-AP5, and L-type Ca(2+) channel blockers, suggesting that Ca(2+)-permeable-AMPARs are sufficient to induce LTP in the SDH neurons of adult mouse spinal cord. In contrast, the induction of HFS-LTD is reduced in the SDH of GluR2 mutants. These results suggest an important role for AMPAR GluR2 subunit in regulating synaptic plasticity with potential relevance for long-lasting hypersensitivity in pathological states.
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Comparative Study
A pain assessment scale for population-based studies: development and validation of the pain module of the Standard Evaluation Questionnaire.
The objectives of this study were to develop and validate a tool for assessing pain in population-based observational studies and to develop three subscales for back/neck, upper extremity and lower extremity pain. Based on a literature review, items were extracted from validated questionnaires and reviewed by an expert panel. The initial questionnaire consisted of a pain manikin and 34 items relating to (i) intensity of pain in different body regions (7 items), (ii) pain during activities of daily living (18 items) and (iii) various pain modalities (9 items). ⋯ Correlation coefficients between subscales and three validated instruments (WOMAC, SPADI and Oswestry) ranged from 0.62 to 0.79. The final Pain Standard Evaluation Questionnaire (SEQ Pain) included 28 items and the pain manikin and accounted for the multidimensionality of pain by assessing pain location and intensity, pain during activity, triggers and time of onset of pain and frequency of pain medication. It was found to be reliable and valid for the assessment of pain in population-based observational studies.