European journal of pain : EJP
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Temporal summation of pain is suggested to be an important factor during various clinical conditions. Controversies exist as to whether temporal summation exists for Adeltafibre-mediated first pain. The aim of the present human experimental study was to investigate the importance of stimulus configuration (intensity, inter-pulse interval, location) for temporal summation of radiant (laser)- and contact-heat-induced pain. ⋯ Taking the latency from stimulation to perception into consideration, we were able to differentiate and find summation of first (Adeltafibre-mediated) and second pain (C fibre-mediated). Summation of first pain was more pronounced for high (38 degrees C) than for low (30-32 degrees C) baseline temperature. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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The extent of surgical trauma was related to postoperative pain intensity in a previous study. However, more extensive surgical procedures with higher baseline pain intensity did not appear to influence the ability to document the additive analgesic effect of codeine when given with paracetamol, partly due to large interindividual variation in baseline pain intensity. The aim of the present study was to attempt to improve upside assay sensitivity in this dental pain model by: (1) selecting patients with high baseline pain intensity; and (2) closer supervision of outpatients>> drug intake and compliance with protocol. ⋯ More pain relief was revealed when codeine 60 mg was added to paracetamol 1000 mg on the following measures of effect: change of pain intensity with time (p<0.05, Mann-Whitney), sum of pain intensities (p=0.019), pain intensity difference (p=0.05), sum of pain intensity differences (p<0.05), pain reduction index (p<0.05) and global-evaluation score (p=0.006). The study confirms that this dental pain model, when controlled for sufficient and homogeneous baseline pain and patient compliance, does have sufficient upside assay sensitivity to discriminate between paracetamol with and without codeine. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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We have previously reported that intrathecal (i.t.) implantation of bovine chromaffin cells has an anti-allodynic effect in a rat model of mechanical and cold allodynia-like neuropathic pain after spinal cord injury. The technique of encapsulation of the cells by a semipermeable membrane has been developed recently. The present study was undertaken to investigate the effects of encapsulated bovine chromaffin cells on the allodynia-like pain in the same model. ⋯ The results indicate that spinal implantation of encapsulated xenogeneic chromaffin cells may be useful in treating some refractory painful states associated with spinal cord injury. Immunoisolation of chromaffin cells by a semipermeable membrane may inhibit immunorejection, prolong the survival of the cells and enhance their anti-allodynic effect. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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The tricyclic antidepressant imipramine has shown analgesic effect in human clinical and experimental pain studies. The aim of the present study was to test the effect of imipramine on a pure short-term nociceptive stimulus with pin-prick pain quality. In a randomized, placebo-controlled, double-blind, crossover study, the hypoalgesic effect of a single oral dose of 100 mg imipramine was investigated in 10 healthy volunteers. ⋯ This study demonstrates the important fact that a drug may show clear analgesic effect in some experimental pain models while it is without effect in other models; e.g. imipramine is known to affect pain tolerance and summation thresholds. Pre-clinical tests of potentially analgesic drugs should therefore be based on different pain-stimulation modalities. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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The characteristics of chest pain due to suspected acute myocardial infarction and morphine use during the first 3 hospital days are described in a population of 2988 consecutive patients admitted to hospital. The duration of pain was usually less than 24 h (mean 20.9+/-0.55 h), and only 24.8% of patients experienced chest pain of longer duration. The majority of patients had only one attack of pain, but 34.4% experienced four or more attacks during hospitalization. ⋯ When intravenous morphine is given, it attains full effect 20 min after injection. Furthermore, the active morphine metabolites M3G and M6G appear rapidly in the circulation, which could influence the analgesic response to morphine treatment. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.