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The oxygen-15 water bolus positron emission tomography (PET) method was used to image regional brain activity in 4 patients with chronic post-traumatic neuropathic pain confined to one lower limb and in 1 patient with post-herpetic neuralgia. In comparison to 13 normal subjects, scans of the patients disclosed a statistically significant decrease in(More)
The PET H2 15O-bolus method was used to image regional brain activity in normal human subjects during intense pain induced by intradermal injection of capsaicin and during post-capsaicin mechanical allodynia (the perception of pain from a normally non-painful stimulus). Images of regional cerebral blood flow were acquired during six conditions: (i) rest;(More)
Low-frequency oscillations (<0.08 Hz) have been detected in functional magnetic resonance imaging studies, and appear to be synchronized between functionally related areas. The effect of anesthetic agents on cortical activity is not completely characterized. This study assessed the effect of anesthesia on the temporal relations in activity in the motor(More)
Objective.  The safety and efficacy of intrathecal (IT) ziconotide was studied in a randomized, double-blind, placebo-controlled trial. Materials and Methods.  Patients (169 ziconotide, 86 placebo) with severe chronic nonmalignant pain unresponsive to conventional therapy and a visual analog scale of pain intensity (VASPI score) ≥ 50 mm were treated over a(More)
NMDA antagonists and opioids relieve experimentally produced hyperalgesia in animals and humans, presumably by attenuating a heightened central nervous system response to afferent input. A few small studies in patients have suggested that intravenous boluses or rapid infusions of the N-methyl-D-aspartate (NMDA) antagonist ketamine relieve some neuropathic(More)
Because a variety of mechanisms may generate pain in neuropathic pain syndromes, conventional clinical trial methods may fail to identify some potentially useful drugs; a drug affecting just a single mechanism may work in too few patients to yield a statistically significant result for the trial. To test a previous clinical observation that approximately(More)
BACKGROUND Functional magnetic resonance imaging offers a compelling, new perspective on altered brain function but is sparsely used in studies of anesthetic effect. To examine effects on verbal memory encoding, the authors imaged human brain response to auditory word stimulation using functional magnetic resonance imaging at different concentrations of an(More)
BACKGROUND Isoflurane administration is known to increase extracellular dopamine (DA) concentration. Because the dopamine transporter (DAT) is a key regulator of DA, it is likely affected by isoflurane. This study investigates the hypothesis that isoflurane inhibits DA reuptake by causing DAT to be trafficked into the cell. METHODS Rhesus monkeys were(More)
BACKGROUND Isoflurane increases extracellular dopamine concentration and causes trafficking of the dopamine transporter (DAT) in transfected cells. Also, the binding potentials of highly specific positron-emitting DAT ligands are altered by isoflurane in rhesus monkeys. The purpose of this study was to determine the dose-response curve for isoflurane(More)
The authors review research on the intermediate- and long-term effects of taking opioid medication on cognitive functioning in patients with chronic cancer and noncancer pain. Opioids seem to be more likely to worsen cognitive performance during the first few days of use and during the first few hours after a given dose, particularly on timed performance in(More)