Pain
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Erythromelalgia is a condition characterized by attacks of red, hot, painful extremities with relief of symptoms by cooling and aggravation by warmth. Although the main emphasis has been on pathophysiological mechanisms related to circulatory changes, recent reports have focused on an involvement of efferent small nerve fibers indicating a neuropathic component. Since the symptoms resemble those described in neuropathic pain, we wanted to investigate the possible affection of afferent nerve fibers. ⋯ Seven patients had brush-evoked allodynia and fourteen had punctate hyperalgesia inside or close to the symptomatic areas in their feet. When comparing the individual results, there is a tendency to clustering of patients in two separate groups; reduced small fiber input/no hyperalgesia and normal thermal thresholds/hyperalgesia. Our results showing an affection of afferent small nerve fibers together with the nature of the symptoms, suggest that the pain experienced by erythromelalgia patients could have a neuropathic component.
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Comparative Study
Gender differences in pain, coping, and mood in individuals having osteoarthritic knee pain: a within-day analysis.
This study examined gender differences in prospective within-day assessments of pain, pain coping, and mood in men and women having OA, and analyzed gender differences in dynamic relations between pain, mood, and pain coping. A sample of 64 women and 36 men diagnosed as having pain due to osteoarthritis of the knee(s) rated their pain, pain coping, and mood two times each day (once in the afternoon and once in the evening) for 30 days using a booklet format. Two gender differences were found in between person-analyses: women used more problem focused coping than men, and women who catastrophized were less likely than men to report negative mood. ⋯ Third, men were more likely than women to use emotion-focused coping when their mood was more negative. Finally, men were more likely than women to experience an increase in negative mood and a decrease in positive mood in the morning after an evening of increased pain. Taken together, these findings underscore the importance of obtaining multiple daily assessments when studying gender differences in the pain experience.
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Comparative Study
Pain catastrophizing and social support in married individuals with chronic pain: the moderating role of pain duration.
In the current study, 96 married chronic pain patients were recruited from the community to test hypotheses about the roles of catastrophizing and psychological distress in relation to perceived support from close others. It was expected that pain duration would moderate the relationship between catastrophizing and perceived support and between catastrophizing and psychological distress. In addition, distress was hypothesized to mediate the relationship between the pain duration-catastrophizing interaction and support. ⋯ Pain duration did not interact with catastrophizing in relating to psychological distress, which precluded the examination of distress as a mediator between the pain duration-catastrophizing interaction and support. Moreover, psychological distress did not significantly mediate the relationships between pain catastrophizing and perceived support. These findings are discussed in the context of cognitive-behavioral and interpersonal perspectives of pain.
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Comparative Study
c-fos and CRF receptor gene transcription in the brain of acetic acid-induced somato-visceral pain in rats.
We aimed to characterize neuronal and corticotrophin-releasing (CRF) pathways in a model of somato-visceral pain in rats. Male rats received an intraperitoneal (i.p.) injection of either vehicle (controls) or acetic acid (AA) and were sacrificed 1, 2, 3, 4, or 6 h later. Coronal frozen sections of the brain were cut and mRNAs encoding the rat c-fos, CRF(1), CRF(2 alpha,beta) receptors were assayed by in situ hybridisation histochemistry. ⋯ In contrast, no expression of CRF(2) transcripts was observed in the PVN either in basal conditions or after AA i.p. These data argue for an activation of CRF pathways within the PVN in this model of somato-visceral pain. The use of CRF antagonists, particularly of the CRF(1) type, should have an interest in somato-visceral pain pathology.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Pregabalin for the treatment of painful diabetic peripheral neuropathy: a double-blind, placebo-controlled trial.
A randomized, double-blind, placebo-controlled, parallel-group, multicenter, 8-week trial (with subsequent open-label phase) evaluated the effectiveness of pregabalin in alleviating pain associated with diabetic peripheral neuropathy (DPN). For enrollment, patients must have had at baseline: 1- to 5-year history of DPN pain; pain score > or =40 mm (Short-Form McGill Pain Questionnaire [SF-MPQ] visual analogue scale); average daily pain score of > or =4 (11-point numerical pain rating scale [0 = no pain, 10 = worst possible pain]). One hundred forty-six (146) patients were randomized to receive placebo (n = 70) or pregabalin 300 mg/day (n = 76). ⋯ Pregabalin was well tolerated despite a greater incidence of dizziness and somnolence than placebo. Most adverse events were mild to moderate and did not result in withdrawal. Pregabalin was safe and effective in decreasing pain associated with DPN, and also improved mood, sleep disturbance, and quality of life.