Pain
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The L5 spinal nerve ligation model of neuropathic pain in rats has been proposed as a model for sympathetically maintained pain (SMP) based on the effects of surgical or chemical sympathectomy on nerve injury induced behavior. In an attempt to confirm that the lesion produces an animal model of SMP, surgical sympathectomies were independently conducted in two different laboratories (Johns Hopkins and University Kiel) using male Sprague-Dawley (n = 30) or Wistar rats (n = 14). The L5 spinal nerve was ligated or cut and ligated. ⋯ Experiments in Wistar and Sprague-Dawley rats yielded the same results. Potential reasons for the discrepancies between the present study and earlier reports are discussed. These results indicate that an L5 spinal nerve injury rat model is not a reliable model for SMP.
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The systemic administration of anti-nerve growth factor (NGF) antibodies can prevent local sensory hypersensitivity and block nociceptive fibers from sprouting into denervated adult rat skin. However, in the case of chronic constriction injury (CCI) in a rat, there is evidence that NGF reverses some effects of axotomy and alleviates thermal hyperalgesia. It is with this in mind that we investigated the influence of local anti-NGF and NGF on neuropathic pain and collateral sprouting caused by CCI. ⋯ The results show that the effect of anti-NGF is delayed at the onset, is short in duration, and is dependent on the dosage. However, anti-NGF but not NGF blocked collateral sprouting and decreased the severity of autotomy, suggesting that anti-NGF may be a better potential alternative analgesic for the treatment of neuropathic pain in humans. The different initiation times to abolish thermal hyperalgesia by anti-NGF (delayed onset) and NGF (early onset) suggests that alterations in neurotrophic factors contribute to the development of behavioral hyperalgesia via a complex mechanism in CCI rats.
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Randomized Controlled Trial Multicenter Study Clinical Trial
Oral transmucosal fentanyl citrate (OTFC) for the treatment of breakthrough pain in cancer patients: a controlled dose titration study.
Oral transmucosal fentanyl citrate (OTFC) is a novel opioid formulation in which the potent synthetic mu-agonist fentanyl is embedded in a sweetened matrix that is dissolved in the mouth. It is undergoing investigation as a treatment for cancer-related breakthrough pain, a prevalent phenomenon defined as a transitory flare of moderate to severe pain that interrupts otherwise controlled persistent pain. There have been no controlled trials of other treatments for this condition. ⋯ OTFC appears to be a safe and effective therapy for breakthrough pain, and dose titration can usually identify a unit dose capable of providing adequate analgesia. If the lack of a relationship between the effective OTFC dose and fixed schedule opioid regimen is confirmed, dose titration may be needed in the clinical use of this formulation. Further investigation of OTFC as a specific treatment for breakthrough pain is warranted.
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Randomized Controlled Trial Clinical Trial
Spatial and temporal summation of sensory and affective dimensions of deep somatic pain.
There is considerable evidence in support of differential information processing of the sensory-discriminative and motivational-affective meanings of pain. The purpose of this work was to examine whether temporal (acute, tonic, persistent) and spatial (local, regional, widespread) aspects of deep somatic pain influence the sensory and affective dimensions of pain. Acute pain consisted of a short bout of pain, lasting about 100 s. ⋯ Affective scores showed the most significant increases from acute to tonic pain, particularly with greater spatial involvement. The significant increases in sensory scores observed when contrasting persistent facial pain alone and in combination with widespread musculoskeletal pain was attributed to the broader body experience. Because the perceptual correlates of tonic and matched persistent (chronic) pain states were similar, we concluded that it does not require months for the development of the sensory and affective meaning of persistent pain as assumed.
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Comparative Study Clinical Trial
Postoperative pain assessment and management in adolescents.
A 3-year study investigated the experience and management of postoperative pain following elective surgery in an adolescent sample, using a variety of valid, reliable instruments and semi-structured interviews. In addition to the adolescent subjects, the views of one parent of each adolescent were sought and a sample of health professionals comprising surgeons, anaesthetists and nurses were interviewed about acute pain in adolescent patients. ⋯ Pain, experienced by most adolescents on the 1st and 3rd postoperative days, was influenced by the presence of anxiety and depression, in addition to the maturational stage; differences between in-patients and day cases are highlighted. Recommendations for practice include the need for more effective pain management and raising awareness of the importance of both psychological state and adjustment to adolescence in this age-group.