Pain
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Back pain severity has extensively been targeted in clinical and epidemiologic studies. However, despite the importance of a valid pain severity grading its adequate conceptualization in the general population has received comparatively little attention. The potentially misleading influence of measurement error remains unclear. ⋯ This classification showed statistically significant and clinically important associations to health-related variables. Our results confirm the high burden of back pain in the general population but suggest a different categorization of those with severe back pain. This entails consequences on how to best target this important health problem from a public health perspective.
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Plasticity in the spinal dorsal horn may contribute to the development of pain following peripheral nerve injury. Shank proteins are a constituent family of the post-synaptic density (PSD), and they may play a role in synaptic plasticity through activity-dependent synaptic remodeling and growth. In this study we examined the early consequences of the loose ligation of the sciatic nerve on Shank1 protein and message levels in the PSD of spinal dorsal horn neurons. ⋯ The same pre-treatment prevented both the early signs of pain behavior. Intrathecal pre-treatment with either MK-801 or U0126 similarly prevented the Shank1 accumulation and alleviated both the behavioral signs of pain. The early accumulation of Shank1 in the PSD of dorsal horn neurons may be a necessary step in the injury-associated plasticity that in time leads to the development of persistent pain.
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More than 1 in 10 adults in the general population experience chronic widespread body pain (CWP), which lies at one end of a continuous spectrum of pain ranging in both severity and duration. Neuroendocrine factors can modify the effect of known psychological and psychosocial risk factors for progression along the spectrum of pain and development of CWP, and genetic variants that affect neuroendocrine and neural processing potentially affect susceptibility to chronic pain development. We have examined variants across genes encoding the beta2-adrenergic receptor (ADRB2) and catecholamine-O-methyltransferase (COMT) - key neuroendocrine signalling factors - in a large population-based sample to determine whether these may be involved in pain progression and CWP development. ⋯ There were no associations of either CWP or pain status with COMT genotypes or haplotypes. These results are the first to suggest that functional ADRB2 variants are involved in regulating pain status at a population level. A role for COMT in chronic pain development was not identified, though could not be excluded.
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The Quantitative Sensory Testing (QST) protocol of the German research network on neuropathic pain (DFNS) encompassing all somatosensory modalities assesses the functioning of different nerve fibers and of central pathways. The aim of our study was: (1) to explore, whether this QST protocol is feasible for children, (2) to detect distribution properties of QST data and the impact of body site, age and gender and (3) to establish reference values for QST in children and adolescents. The QST protocol of the DFNS with modification of instructions and pain rating was used in 176 children aged 6.12-16.12years for six body sites. ⋯ Girls were more sensitive to thermal detection and pain stimuli, but not to mechanical detection and pain stimuli. Reference values differ from adults, but distribution properties (range, variance, and side differences) were similar and plausible for statistical factors. Our results demonstrate that the full QST protocol is feasible and valid for children over 5years of age with their own reference values.