Pain
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To examine the pathophysiological mechanisms of vascular disturbances and to assess the role of the sympathetic nervous system, 12 patients with reflex sympathetic dystrophy (RSD) of the hand were studied using laser Doppler flowmetry. Cutaneous blood flow, skin resistance and skin temperature were measured at the affected and contralateral hands. Sympathetic vasoconstrictor reflexes were induced bilaterally by deep inspiration. ⋯ Therefore, they have to be interpreted with care when defining reliable diagnostic criteria. (2) Vascular disturbances in RSD are not due to constant overactivity of sympathetic vasoconstrictor neurons. Changes in vascular sensitivity to cold temperature and circulating catecholamines may be responsible for vascular abnormalities. Alternatively, RSD may be associated with an abnormal (side different) reflex pattern of sympathetic vasoconstrictor neurons due to thermoregulatory and emotional stimuli generated in the central nervous system. (3) After sympathectomy, denervation supersensitivity of blood vessels and intense vasomotion may be associated with recurrence of pain in some patients.
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The present report provides evidence that axons in the medial part of the posterior column at T10 convey ascending nociceptive signals from pelvic visceral organs. This evidence was obtained from human surgical case studies and histological verification of the lesion in one of these cases, along with neuroanatomical and neurophysiological findings in animal experiments. A restricted lesion in this area can virtually eliminate pelvic pain due to cancer. ⋯ Since it is reasonable to attribute the favorable results of limited midline myelotomies to the interruption of axons of visceral nociceptive projection neurons in the posterior column, we have performed experiments in rats to test this hypothesis. The results in rats indicate that the dorsal column does indeed include a nociceptive component that signals pelvic visceral pain. The pathway includes neurons of the postsynaptic dorsal column pathway at the L6-S1 segmental level, axons of these neurons in the fasciculus gracilis, and neurons of the nucleus gracilis and the ventral posterolateral nucleus of the thalamus.
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This study assesses the anti-inflammatory/analgesic effects of ketoprofen a non-steroidal anti-inflammatory drug, using the method of c-Fos immunoreactivity at the spinal cord level in two models of noxious stimulation: carrageenan-induced inflammatory pain or acute noxious heat. Ketoprofen was pre-administered intravenously or orally 25 min before an intraplantar injection of carrageenan (6 mg in 150 microliters of saline) in hindpaw of the non-anaesthetised rat or before a single noxious heat (52 degrees C, 15 sec) stimulation of hindpaw of the anaesthetised rat. Three hours after carrageenan or 2 h after noxious heat, the number of spinal c-Fos protein-like immunoreactive (c-Fos-LI) neurons in L4-L5 segments and both the ankle and paw diameter, the indicator of peripheral oedema, were assessed. ⋯ In contrast, the same doses of both the intravenous and oral pre-administration of ketoprofen did not influence either the spinal c-Fos protein expression nor slightly enhanced paw diameter induced by a single noxious heat stimulation. This study suggests a predominant peripheral site, without excluding a central site of action of ketoprofen in the carrageenan-induced inflammation. The method of c-Fos protein-like immunoreactivity revealed ketoprofen to be more potent in comparison to members of other families of non-steroidal anti-inflammatory drugs, previously studied in the same experimental conditions of carrageenan-induced inflammatory pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Epidural and subcutaneous morphine in the management of cancer pain: a double-blind cross-over study.
Ten patients who suffered from severe cancer-related pain participated in a randomised, double-blind and cross-over study to compare the effectiveness and acceptability of epidural and subcutaneous administration of morphine. The patients titrated themselves pain-free in 48 h using a patient controlled analgesia system. ⋯ The two modes of morphine administration turned out to be comparable in terms of both effectiveness and acceptability. Both treatments provided better pain relief with less adverse effects compared with the prestudy oral morphine treatment.
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The nature and duration of pain associated with herpes zoster is highly variable. This review of research on pain in acute herpes zoster and postherpetic neuralgia (PHN) explores those observations relevant to the definition and pathogenesis of PHN and the design of treatment trials. A model for the pathogenesis of PHN is presented, which gains support from studies of risk factors. Several directions for future research are identified.