Pain
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Questions have been raised about the potential neurotoxicity of the neuraxial use of ketamine although ketamine and its active enantiomer S(+)-ketamine have been used intrathecally and epidurally (caudally) for the management of perioperative pain and in a variety of chronic pain syndromes. Clinical experience following neuraxial administration of S(+)-ketamine has been documented without reference to local central nervous system toxicity following this approach. ⋯ However, postmortem observation of the spinal cord and nerve roots revealed severe histological abnormalities including central chromatolysis, nerve cell shrinkage, neuronophagia, microglial upregulation, and gliosis. Based on our results, neuraxial administration of S (+)-ketamine cannot be recommended for clinical practise before a systematic study of toxicology of neuraxial S(+)-ketamine in animals or humans has been performed.
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Comparative Study
Pronociceptive role of peripheral and spinal 5-HT7 receptors in the formalin test.
The possible pronociceptive role of peripheral and spinal 5-HT7 receptors in the formalin test was assessed. Local administration of 5-HT7 (SB-269970, 2.5-77.1 nmol/paw), but not 5-HT(1A) (WAY-100635, 1-60 nmol/paw), receptor antagonist significantly reduced formalin-induced flinching. Local 5-hydroxytryptamine (5-HT, 3-100 nmol/paw) or 5-carboxamidotryptamine (5-CT, 0.3-3 nmol/paw) (a 5-HT7/1A receptor agonist) augmented, in a dose-dependent manner, 0.5% formalin-induced nociceptive behavior. ⋯ In addition, the spinal antinociceptive effect of 5-CT was partially reversed by WAY-100635 (10 nmol/rat). The spinal antinociceptive effect of 5-HT was unaffected either by SB-269970 (77 nmol/rat) or WAY-100635 (10 nmol/rat). Data suggest that 5-HT7, but not 5-HT1A, receptors play a pronociceptive role in peripheral and spinal sites in the rat formalin test.
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Comparative Study
A longitudinal study on the predictive validity of the fear-avoidance model in low back pain.
Recently, fear-avoidance models have been quite influential in understanding the transition from acute to chronic low back pain (LBP). Not only has pain-related fear been found to be associated with disability and increased pain severity, but also treatment focused at reducing pain-related fear has shown to successfully reduce disability levels. In spite of these developments, there is still a lack in well-designed prospective studies examining the role of pain-related fear in acute back pain. ⋯ A backward ordinal regression analysis showed previous LBP history and pain intensity to be the most important predictors of end of study GCPS. Of the fear-avoidance model variables, only negative affect added to this model. Our results do not really support the longitudinal validity of the fear-avoidance model, but they do feed the discussion on the role of pain-related fear in early stages of LBP.
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In this systematic review effectiveness of analgesics for pain after tonsillectomy in children was evaluated and trial methodology of the included studies explored. Databases were searched for randomised, controlled studies on systemic paracetamol, NSAIDs and opioids. Eighty-four studies were evaluated for inclusion. ⋯ Because of highly variable methodology and lack of sensitivity only limited conclusions on clinical efficacy of analgesics investigated can be drawn. No analgesic in single prophylactic dose provided analgesia for day of operation. Further studies are needed to find the optimal analgesic(s) for pain after tonsillectomy in children.