Pain
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Comparative Study
Heterotopic nociceptive conditioning stimuli and mental task modulate differently the perception and physiological correlates of short CO2 laser stimuli.
The present study was aimed at examining the specificity of the action of heterotopic nociceptive conditioning stimulation (HNCS) by comparing its effects of those induced by a mental task (MT). Five test stimuli made from short CO2 laser pulses (duration: 40 msec; diameter: 10 mm; intensity: 0.25-0.8 Joules) were delivered every 30 to 45 sec at random to 4 different spots on the skin of the upper lip in 3 groups of 10 healthy subjects. The two most intense stimuli were perceived as painful, the two least intense stimuli as warm, and the intermediate stimulus as hot or near painful. ⋯ Pain perception (first pain) threshold was increased in both conditioning stimulations; however, the stimulus-response curve and the neurophysiological correlates were differently affected. During HNCS, the stimulus-response curve was depressed and T was increased mainly for the intermediate stimulus, whilst CEP power density was reduced for all stimulus intensities; discrimination performance near pain threshold was dramatically depressed. During MT, the stimulus-response curve was shifted down toward higher stimulus intensities, T was equally increased for all stimulus intensities, whereas CEP power density was not changed; discrimination performance remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
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A consecutive sample of 53 chronic cancer pain patients were administered 5 different pain intensity scales: a visual analogue scale (VAS), a numerical rating scale from 0 to 10 (NRS), a verbal rating scale (VRS), the Italian Pain Questionnaire (Italian version of the McGill Pain Questionnaire) (PRI), and the Integrated Pain Score (IPS) which is an instrument designed at the Pain Therapy and Palliative Care Division of the National Cancer Institute of Milan to integrate pain intensity and duration in a single measure. These scales were administered before and after a definite therapy change. ⋯ A single factor clearly emerged explaining most of the different scales variability. A logistic regression analysis showed that VAS, NRS, VRS were more strongly associated with IRS than PRI and IPS.
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The streptozocin-induced diabetic rat has been put forward as a model of chronic pain with signs of hyperalgesia and allodynia that may reflect signs observed in diabetic humans. The aim of this work was to assess, in streptozocin-induced diabetic rats, the pharmacological activity to several analgesic drugs known to be effective (clomipramine, amitriptyline, desipramine, clonidine, lidocaine), ineffective (aspirin), or with a doubtful effectiveness (morphine) in human painful diabetic neuropathy. The animals were submitted to a mechanical pain test (paw pressure) and the ability of the drugs to reverse diabetes-induced hyperalgesia was tested. ⋯ Lidocaine (1-9 mg/kg, i.v.) had prolonged efficacy on mechanical hyperalgesia. Aspirin (100 mg/kg, i.v.) was without effect and morphine (0.5-4 mg/kg, i.v.) induced a dose-dependent antinociceptive effect but at doses twice as high as those used in normal rats. These results demonstrate the high pharmacological predictivity of this model of painful diabetes and suggest that in this pathological condition, among the drugs acting on monoaminergic transmission, noradrenergic drugs seem the most active.
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Randomized Controlled Trial Comparative Study Clinical Trial
Patient-controlled epidural analgesia in obstetric anaesthetic practice.
A randomised single-blind controlled study was made of 60 patients to evaluate the effectiveness of epidural patient-controlled analgesia (PCA) device for obstetric management compared with a continuous infusion system. In both cases 0.125% plain bupivacaine was used. It was found that epidural PCA is at least as effective as an infusion system in producing analgesia and has the advantages of increased satisfaction and reduction of local anaesthetic requirement. Whether there are also advantages resulting from less obstetric intervention at delivery has not been proven.
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Review Historical Article
The role of psychological factors in chronic pain. I. A half century of study.
This review examines a half century of thought about the role of psychological factors in chronic pain. Changing views are discussed, and representative examples of pain research based on psychoanalytic, behavioural, cognitive, and psychophysiological theories are presented and evaluated. ⋯ Studies reviewed show that an earlier concept, based on simple formulations of psychological causation, has been replaced by more comprehensive explanations comprising both physical and psychological influences. Further methodological and conceptual problems are discussed in the second paper of this 2-part review.