European journal of pain : EJP
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The present study examined the influence of innocuous skin cooling on the perception and neurophysiological correlates of brief noxious CO2 laser stimuli. In nine normal subjects, brief CO2 laser pulses of four different intensities (duration 50 ms; diameter 5 mm; intensity range 5.8-10.6 mJ/mm2) were delivered at random every 5-10 s on the dorsum of the hand. Innocuous skin cooling was performed by a thermode (20 degrees C; 3x3 cm) with a central hole for the laser test stimuli. ⋯ Reaction times were delayed. The late-LEPs, correlates of Adelta-nociceptor activations, were also significantly depressed while the ultra-late LEPs, correlates of C-nociceptors, were not affected. Taken together, these results strongly suggest that innocuous skin cooling interfered with the sensory processing of laser heat stimuli and more prominently with those related to Adelta-nociceptive input.
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Buprenorphine is a potent opioid analgesic with partial agonistic properties at mu-opioid receptors. This study investigated the interaction potential with several full mu-agonists in the tail-flick test in mice. We further examined the reversibility of buprenorphine antinociception by different mu-opioid receptor antagonists. ⋯ Our results suggest that the antinociceptive effect of buprenorphine is mainly, if not exclusively, mediated by activation of mu-opioid receptors. They confirm clinical experience that in the analgesic dose range a switch between buprenorphine and full mu-agonists is possible without loss of analgesic efficacy and without a refractory period between the termination of buprenorphine analgesia and the onset of action of the new mu-opioid treatment. Antinociception of buprenorphine is sensitive towards mu-opioid receptor antagonists and incomplete inhibition can be improved by increasing the dose or repetitive dosing.
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Review Meta Analysis
Human brain mechanisms of pain perception and regulation in health and disease.
The perception of pain due to an acute injury or in clinical pain states undergoes substantial processing at supraspinal levels. Supraspinal, brain mechanisms are increasingly recognized as playing a major role in the representation and modulation of pain experience. These neural mechanisms may then contribute to interindividual variations and disabilities associated with chronic pain conditions. ⋯ The nociceptive system is now recognized as a sensory system in its own right, from primary afferents to multiple brain areas. Pain experience is strongly modulated by interactions of ascending and descending pathways. Understanding these modulatory mechanisms in health and in disease is critical for developing fully effective therapies for the treatment of clinical pain conditions.
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Randomized Controlled Trial Clinical Trial
The effect of venlafaxine on ongoing and experimentally induced pain in neuropathic pain patients: a double blind, placebo controlled study.
The aim of this randomized double blind placebo controlled study was to investigate the effectiveness and the safety of venlafaxine XR 75 and 150 mg on ongoing pain and on quantitative sensory tests in 60 patients with neuropathic pain for 8 weeks. ⋯ The study showed significant effect of venlafaxine in the manifestations of hyperalgesia and temporal summation, but not on the ongoing pain intensity. Furthermore, the quantitative sensory tests provided complementing information to the clinical measures.
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There is a lack of valid epidemiological data on malignancy-associated pain in modern pediatric oncology. Pediatric oncology patients (self-assessment) and their parents from 28 hospitals were questioned using age-adapted, structured interviews and validated pain assessment tools. Pain intensity was measured by the NRS and Bieri faces scale. ⋯ Multivariate analyses depicted general physical condition either "severely reduced" (ASA status 3) (OR 4.0, 95% CI 1.1-14.7, p=0.037) or "moderately reduced" (ASA status 2) (OR 1.8, 95% CI 1.1-2.9, p=0.018), "in-patient status" (OR 1.8, 95% CI 1.2-2.9, p=0.010), and "co-morbidity present" (OR 3.5, 95% CI 1.1-10.7, p=0.030) as risk factors for severe to maximal pain. General anesthesia was the only factor significantly (OR 0.14, 95% CI 0.05-0.39, p<0.01) associated with a reduction in the proportion of patients suffering severe to maximal pain during bone marrow aspiration. Our data emphasize both the importance of in-house acute pain control and the need for general anesthesia during painful procedures in pediatric oncology.