The journal of pain : official journal of the American Pain Society
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There is growing interest in the role that positive aspects of psychological adjustment, such as pain acceptance, hope, and optimism, may play in explaining adjustment in persons suffering from persistent pain. This study conducted in obese patients with persistent musculoskeletal pain (N = 89) examined the degree to which pain acceptance and hope explained pain intensity, pain unpleasantness, psychological distress, and pain-related disability, after controlling for the effects of optimism. In correlational analyses, pain acceptance and optimism were associated with psychological distress and pain disability with hope being related to only psychological distress. Pain acceptance, optimism, and hope were not significantly associated with pain. Hierarchical linear regression (HLR) analyses found that pain acceptance remained a significant predictor of psychological distress and pain disability after controlling for optimism, demographic, and medical variables. HLR analyses found that hope was not a significant predictor of psychological distress after controlling for optimism, pain acceptance, and demographic and medical variables. The results of this study are important because they indicate that pain acceptance, hope, and optimism are all related to pain adjustment. They also highlight the importance of controlling for optimism when examining the effects of pain acceptance and hope on pain adjustment. ⋯ In a sample of obese patients with persistent musculoskeletal pain, pain acceptance was a significant predictor of psychological distress and pain disability even after controlling for optimism, demographic, and medical variables. These results add to the growing literature on the importance of pain acceptance in understanding adjustment to persistent pain.
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Glial cell line-derived neurotrophic factor (GDNF), a survival-promoting factor for a subset of nociceptive small-diameter neurons, has been shown to exert analgesic effects on neuropathic pain. However, its detailed mechanisms of action are still unknown. In the present study, we investigated the site-specific analgesic effects of GDNF in the neuropathic pain state using lentiviral vector-mediated GDNF overexpression in mice with left fifth lumbar (L5) spinal nerve ligation (SNL) as a neuropathic pain model. A lentiviral vector expressing both GDNF and enhanced green fluorescent protein (EGFP) was constructed and injected into the left dorsal spinal cord, uninjured fourth lumbar (L4) dorsal root ganglion (DRG), injured L5 DRG, or plantar skin of mice. In SNL mice, injection of the GDNF-EGFP-expressing lentivirus into the dorsal spinal cord or uninjured L4 DRG partially but significantly reduced the mechanical allodynia in association with an increase in GDNF protein expression in each virus injection site, whereas injection into the injured L5 DRG or plantar skin had no effects. These results suggest that GDNF exerts its analgesic effects in the neuropathic pain state by acting on the central terminals of uninjured DRG neurons and/or on the spinal cells targeted by the uninjured DRG neurons. ⋯ This article shows that GDNF exerts its analgesic effects on neuropathic pain by acting on the central terminals of uninjured DRG neurons and/or on the spinal cells targeted by these neurons. Therefore, research focusing on these GDNF-dependent neurons in the uninjured DRG would provide a new strategy for treating neuropathic pain.
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The objective of this study was to assess the quality of websites presenting treatment information for postherpetic neuralgia. The term "postherpetic neuralgia treatment" was searched using the Google and Yahoo search engines. Fifty websites from each were evaluated using the Journal of the American Medical Association (JAMA) benchmarks, the Health on the Net (HON) seal, and the DISCERN instrument. The treatments suggested on each website were compared with 3 recognized first-line treatment options (antidepressants, anticonvulsants, and topical lidocaine). Less than half of the included websites fulfilled all JAMA benchmark requirements. Less than one-third of the websites displayed the HON seal. The DISCERN instrument evaluation revealed that most websites were of moderate quality. Commercial websites tended to be inferior in comparison to noncommercial websites. Most websites recommended at least 2 of the 3 recommended treatments as well as several second- and third-line treatments. One-third to one-half of websites recommended a nonbeneficial treatment. In conclusion, many different postherpetic neuralgia treatments are found on the Internet and patients may be left separating recommended treatments from nonrecommended treatments without help from their healthcare providers. ⋯ This study examined the quality of websites related to postherpetic neuralgia treatment. The results demonstrated that most websites offering advice on postherpetic neuralgia treatment are of only moderate quality and often offer treatment suggestions that are nonbeneficial. Patients and providers must use caution when taking advice from these sites.