Pain
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Complex regional pain syndrome (CRPS) is a painful condition affecting one or more extremities of the body, marked by a wide variety of symptoms and signs that are often difficult to manage because the pathophysiology is incompletely understood. Thus, diverse treatments might be ineffective. A recent report revealed the presence of autoantibodies against differentiated autonomic neurons in CRPS patients. ⋯ We identified these autoantibodies as immunoglobulin G directed against peptide sequences from the second extracellular loop of these receptors. The identification of functionally active autoantibodies in serum samples from CRPS patients supports an autoimmune pathogenesis of CRPS. Thus, our findings contribute to the further understanding of this disease, could help in the diagnosis in future, and encourage new treatment strategies focusing on the immune system.
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We have proposed that neuropathic pain engages emotional learning, suggesting the involvement of the hippocampus. Because cytokines in the periphery contribute to induction and maintenance of neuropathic pain but might also participate centrally, we used 2 neuropathic pain models, chronic constriction injury (CCI) and spared nerve injury (SNI), to investigate the temporal profile of hippocampal cytokine gene expression in 2 rat strains that show different postinjury behavioral threshold sensitivities. SNI induced long-lasting allodynia in both strains, while CCI induced allodynia with time-dependent recovery in Sprague Dawley (SD) and no allodynia in Wistar Kyoto (WK) rats. ⋯ Conversely, in SD rats, SNI resulted in sustained and robust increased hippocampal IL-1β expression, which was only transient in rats with CCI. In this strain, IL-6 expression was not affected in any of the 2 injury models and IL-1ra expression was significantly increased in rats with SNI or CCI at late phases. We found that the degree and development of neuropathic pain depend on the specific nerve injury model and rat strain; that hippocampal IL-1β mRNA levels correlate with neuropathic pain behavior; that, in contrast to sham-operated animals, there are no correlations between hippocampal IL-1β and IL-1ra or IL-6 in neuropathic rats; and that alterations in cytokine expression are restricted to the hippocampus contralateral to the injury side, again implying that the observed changes reflect nociception.
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Multicenter Study
The mediating role of pain in substance use and depressive symptoms among Multicenter AIDS Cohort Study (MACS) participants.
Pain in human immunodeficiency virus (HIV) frequently co-occurs with substance use and depression. The complex associations among patient characteristics, pain, depression, and drug use in HIV suggests a role for testing models that can account for relationships simultaneously, control for HIV status, and also test for mediation. Using structural equation modeling, the current study examined associations among pain, sociodemographics, illicit drug use, and depressive symptoms in 921 HIV-seropositive and 1019 HIV-seronegative men from the Multicenter AIDS Cohort Study, an ongoing prospective study of the natural history of HIV infection among gay/bisexual men. ⋯ HIV-seropositive status predicted more use of inhaled nitrites. In this cohort, having lower CD4+ cell counts (predicted by HIV status), being African American, less educated, and older were all associated with more pain, which, in turn, was associated with more illicit drug use and more depressive symptoms. The results underscore the need for adequate pain management, particularly among vulnerable subgroups of HIV-seropositive and HIV-seronegative men to reduce the risk of drug use and depression.
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Persistent postoperative pain is a common complication of surgery, including surgical interventions for cancer. So far, there is limited information about the prevalence and clinical characteristics of pain after lymph node biopsy and dissection in patients with malignant melanoma. In this study, a questionnaire was sent out to all surviving patients (n=402) after surgery for cutaneous malignant melanoma at the Aalborg Hospital Department of Plastic Surgery, Aalborg, Denmark. ⋯ At the clinical follow-up, 10 out of 12 patients with pain both met the criteria of the recently proposed grading system for probable neuropathic pain and used descriptors on the DN4 questionnaire suggestive of neuropathic pain. Different patterns of sensory profiles were observed in single patients, suggesting heterogeneous sensory processing within single patients. This study suggested that nerve injury was the main underlying mechanism of persistent pain after lymph node excision.
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Recent research has begun to examine discrete caregiver pain management behaviors in the infant immunization context. However, there is a dearth of research exploring more global caregiving constructs, such as emotional availability, which can be used to examine the overall sensitivity of caregiver pain management. The aim of the present study was to examine the relationships between caregiver sensitivity (emotional availability) and infant pain behavior (baseline, immediately post-needle, 1 min after needle) over the first year of life. ⋯ Caregiver sensitivity to the infant in pain is predicted most reliably from previous caregiver sensitivity, not infant pain behaviour. The significant concurrent relationship between caregiver sensitivity and infant pain behaviours is not seen until 12 months, replicating patterns in the infant development literature regarding the time at which the attachment relationship between parent and child can be reliably measured. Discussion addresses implications for both researchers and clinicians who work with infants in pain.