Pain
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Central pain syndromes (CPS) could be caused by disinhibition of spinothalamic excitability or by other central nervous system (CNS) changes caused by reduced spinothalamic function. To examine these possibilities, we studied 11 patients (ages 51-82 years) with unilateral central pain and with reproducible cerebral evoked vertex potentials in response to cutaneous stimulation of the normal side with pulses from an infra-red CO2 laser. All patients had normal tactile and kinesthetic sensation; one had slightly decreased vibratory sense bilaterally. ⋯ In contrast, laser stimulation of the affected side failed to evoke either N or P potentials in 6 patients, all of whom had lateralized increased thresholds for warm, heat pain, or deep pain, or reduced ratings of laser pulse sensation. Although 1 patient had increased ratings of laser pulse sensation, the amplitude of the LEP was always reduced on the side of increased pain or heat threshold in these CPS patients (Fisher exact test: P = 0.015). These results reflect primarily a deficit in spinothalamic tract function and do not suggest excessive CNS responses to synchronous activation of cutaneous heat nociceptors in patients with CPS.
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Randomized Controlled Trial Clinical Trial
The opposite effects of the opiate antagonist naloxone and the cholecystokinin antagonist proglumide on placebo analgesia.
Discovery of the involvement of endogenous opiates in placebo analgesia represents an important step in understanding the mechanisms underlying placebo response. In the present study, we investigated the effects of the opiate antagonist naloxone and the cholecystokinin antagonist proglumide on placebo analgesia in a human model of experimentally induced ischemic pain. First, we found that part of the placebo response was reversed by naloxone, confirming previous studies on the role of opioids in the placebo phenomenon. ⋯ The placebo effect can thus be modulated in two opposite directions: it can be partially abolished by naloxone and potentiated by proglumide. The fact that placebo potentiation by proglumide occurred only in placebo responders, but not in non-responders, suggests that activation of an endogenous opiate system is a necessary condition for the action of proglumide. These results suggest an inhibitory role for cholecystokinin in placebo response, although the low affinity of proglumide for cholecystokinin receptors does not rule out the possibility of other mechanisms.
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Comparative Study Clinical Trial Controlled Clinical Trial
Comparison between celiac plexus block and morphine treatment on quality of life in patients with pancreatic cancer pain.
Twenty-one patients with pancreatic cancer pain were studied to evaluate the effectiveness of celiac plexus block (CPB) on pain relief and quality of life (QOL), compared to the traditional NSAID-morphine treatment. The criteria were morphine consumption, visual analogue pain scale (VAS), performance status (PS) determined by medical and nursing staffs, and answers to QOL questionnaires. Morphine consumption, VAS, PS, and self-assessed QOL scores were taken when the administration of morphine was necessary for pain relief and those scores were used as control. ⋯ Self-assessed QOL scores did not ameliorate statistically after CPB; however, they did deteriorate remarkably in the patients treated only with morphine-NSAID during their survival periods, while they deteriorated only slightly in the CPB group. There were fewer side effects after CPB. These results indicate CPB does not directly improve QOL in patients with pancreatic cancer pain, but it may prevent deterioration in QOL by the long-lasting analgesic effect, limitation of side effects and the reduction of morphine consumption, compared to treatment only with NSAID-morphine.
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Comparative Study Clinical Trial
Active and passive coping strategies in chronic pain patients.
This study assessed the validity of active and passive coping dimensions in chronic pain patients (n = 76) using the Coping Strategies Questionnaire and the Vanderbilt Pain Management Inventory. The validity of active and passive coping dimensions was supported; passive coping was strongly related to general psychological distress and depression, and active coping was associated with activity level and was inversely related to psychological distress. In addition, the Coping Strategies Questionnaire was found to be a more psychometrically sound measure of active and passive coping than the Vanderbilt Pain Management Inventory.
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Clinical Trial
Anger management style, hostility and spouse responses: gender differences in predictors of adjustment among chronic pain patients.
This study examined whether relationships between anger management style (anger suppression; anger expression) and adjustment variables for patients with chronic pain depend on patient hostility, and/or depend on a patient's gender. A 'spouse response model' was also evaluated to test whether patient expression of hostile anger is linked to infrequent positive and frequent negative responses from spouses, and hence to poor adjustment. ⋯ Among men, support was also found for a spouse response model: pain severity and activity interference for High Anger Expressors was partly accounted for by negative spouse responses. Results suggest that discriminations among patients may be made based on anger management style in interaction with level of hostile attitude and the patient's gender, and that these distinctions may have implications for understanding mechanisms of pain and disability, and for designing appropriate treatment.