Pain
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Multicenter Study Comparative Study
Sensory profiles and immune related expression patterns of patients with and without neuropathic pain after peripheral nerve lesion.
In this multicenter cross-sectional study, we determined sensory profiles of patients with (NL-1) and without neuropathic pain (NL-0) after nerve lesion and assessed immune-related systemic gene expression. Patients and matched healthy controls filled in questionnaires and underwent neurological examination, neurophysiological studies, quantitative sensory testing, and blood withdrawal. Neuropathic pain was present in 67/95 (71%) patients (NL-1). ⋯ Gene expression of peptidylglycine α-amidating monooxygenase was higher in NL patients compared with healthy controls (NL-1, P < 0.01; NL-0, P < 0.001). Also, gene expression of tumor necrosis factor-α was higher in NL-1 patients compared with NL-0 (P < 0.05), and interleukin-1ß was higher, but IL-10 was lower in NL-1 patients compared with healthy controls (P < 0.05 each). Our study reveals that nerve lesion presents with small and large nerve fiber dysfunction, which may contribute to the presence and intensity of neuropathic pain and which is associated with a systemic proinflammatory pattern.
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Chronic pain continues to be a significant global burden despite the availability of a variety of nonpharmacologic and pharmacologic treatment options. Thus, there is a need for new analgesics with novel mechanisms of action. ⋯ The potential role of NGF in osteoarthritis and chronic low-back pain signaling is also examined to provide a mechanistic basis for the observed efficacy of NGF-Abs in clinical trials of these particular pain states. Finally, the safety profile of NGF-Abs in terms of common adverse events, joint safety, and nerve structure/function is discussed.
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Arrhythmic fluctuations in neural activity occur at many levels of the nervous system. Such activity does not have a characteristic temporal periodicity but can exhibit statistical similarities, most commonly power-law scaling behavior, which is indicative of scale-free dynamics. The recurrence of scaling laws across many different systems and its manifestation in behavior has prompted a search for unifying principles in human brain function. ⋯ Increases in the scaling exponent were positively correlated with fMRI signal variance and negatively correlated with the patient's self-reported headache intensity. These changes in the fMRI signal suggest that the temporal structure of amplitude fluctuations carries valuable information about the dynamic state of the underlying neuronal networks and ensuing sensory impairments in migraine. The demonstrated scaling laws pose a novel quantitative approach for examining clinically relevant interindividual variability in migraine and other pain disorders.