European journal of pain : EJP
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L5 and L6 spinal nerve ligation (SNL) in rats leads to behavioral signs of neuropathic pain including mechanical allodynia. The purposes of this study were to investigate the role of the intact L4 spinal nerve in the development of mechanical allodynia following L5 and L6 SNL and, as a result, to develop a modified model of neuropathic pain. As a first set of experiments, in addition to tight ligation of the left L5 and L6 spinal nerves, the intact L4 spinal nerve was manipulated either (1) by gentle repeated stretching of the L4 spinal nerve immediately after L5 and L6 SNL or (2) by intermittent mechanical stimulation to the ipsilateral paw during the first week after SNL. ⋯ These results suggest that afferent activity of the intact L4 spinal nerve aids in the development of mechanical allodynia in the SNL model of neuropathic pain. The addition of a chromic gut loop around the intact L4 spinal nerve can augment the development of mechanical allodynia following SNL of L5. We propose this latter as a useful and practical animal model of neuropathic pain.
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We have recently demonstrated dose-related analgesic-induced reductions in the occurrence of 7 behavioural activities following midline laparotomy in rats. For these behaviours to be useful in evaluating pain in laboratory rats they must be shown to occur after different types of surgery, and frequently enough to allow rapid scoring of animals. Here, the relevant behaviours were used to test the analgesic efficacy of meloxicam with a variation of our previous laparotomy model. ⋯ Irrespective of whether analyses included only 5 or all 10 min of the observation period, the relevant behaviours occurred significantly more often in rats given saline or low dose meloxicam than in those given 1 or 2 mg/kg of meloxicam, or any dose of carprofen. We conclude that this technique of quantifying post-surgery behaviour is an effective pain scoring method following abdominal surgery in rats, and that 1 mg/kg meloxicam significantly attenuates laparotomy induced pain. Since only a short observation period is required, this approach represents an important practical advance in assessing abdominal pain severity and clinical drug potency.
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In this paper, it is investigated whether an implicit evaluative-negative attitude towards back-stressing activities exists in pain-free subjects and in chronic low back pain patients. Using an affective priming task, it was investigated whether pictures of threatening back-stressing movements (primes) facilitate (respectively, slow down) the categorisation of subsequent evaluative-negative (evaluative-positive) words (targets). ⋯ In line with previous research, it is argued that this reverse priming effect is owing to the evaluative extremity of the primes: patients recognize the possibility that extreme primes will interfere with the categorisation of the targets and overcompensate for this possible effect. The implications for the prevention of negative attitudes towards back-stressing activities in non-clinical and clinical samples are discussed.
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The aim of this research was to explore the impact that diagnostic status has on information processing biases among chronic pain (CP) and ankylosing spondylitis (AS) patients. AS patients, CP patients, and healthy hospital staff controls, completed a questionnaire and short computer task. During the computer task participants endorsed sensory, depression, illness, and neutral adjectives, following a cue question (which facilitated encoding of the adjectives in relation to the self). ⋯ The diagnosed AS group showed a bias towards sensory stimuli, perhaps reflecting the presence of an enduring and over-riding pain schema. The non-pain control group also displayed a sensory bias, which was attributed to a frequency effect as a result of working in an environment where they were regularly exposed to sensory language. The results are discussed in relation to existing literature in this area and implications for clinical practice are provided.
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Black and white pain drawings were introduced as a proposed means to identify patients, presenting with low back pain, who demonstrated functional overlay upon neurological testing. The use of color may enhance the usefulness of such pain drawings, but has not been described for adult patients. ⋯ Our findings agree with previous observations using black and white pain drawings, indicating that colored pain drawings are no less useful than the black and white approach. Further research is necessary to examine the psychometric properties and clinical usefulness of colored pain drawings to predict outcomes and/or determine treatment.