Anesthesiology
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Randomized Controlled Trial Comparative Study
Feasibility of closed-loop titration of propofol and remifentanil guided by the spectral M-Entropy monitor.
This randomized controlled trial describes automated coadministration of propofol and remifentanil, guided by M-Entropy analysis of the electroencephalogram. The authors tested the hypothesis that a novel dual-loop controller with an M-Entropy monitor increases time spent within predetermined target entropy ranges. ⋯ Intraoperative automated control of hypnosis and analgesia guided by M-Entropy is clinically feasible and more precise than skilled manual control.
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Comparative Study Clinical Trial
First human administration of MR04A3: a novel water-soluble nonbenzodiazepine sedative.
JM-1232(-), (-)-3-[2-(4-methyl-1-piperazinyl)-2-oxoethyl]-2-phenyl-3,5,6,7-tetrahydrocyclopenta [f]isoindol-1(2H)-one, molecular formula, C(24)H(27)N(3)O(2); molecular weight, 389.49, is a novel isoindoline water-soluble benzodiazepine receptor agonist with favorable anesthetic/sedative properties in animals. MR04A3 is a 1% aqueous presentation of JM-1232(-). ⋯ MR04A3 is hypnotic in man with a satisfactory hemodynamic and safety profile.
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Propofol exposure to neurons during synaptogenesis results in apoptosis, leading to cognitive dysfunction in adulthood. Previous work from our laboratory showed that isoflurane neurotoxicity occurs through p75 neurotrophin receptor (p75(NTR)) and subsequent cytoskeleton depolymerization. Given that isoflurane and propofol both suppress neuronal activity, we hypothesized that propofol also induces apoptosis in developing neurons through p75(NTR). ⋯ These results demonstrate that propofol induces apoptosis in developing neurons in vivo and in vitro and implicate a role for p75(NTR) and the downstream effector RhoA kinase.
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Exposure of rhesus macaque fetuses for 24 h or neonates for 9 h to ketamine anesthesia causes neuroapoptosis in the developing brain. The current study clarifies the minimum exposure required for and the extent and spatial distribution of ketamine-induced neuroapoptosis in rhesus fetuses and neonates. ⋯ The developing rhesus macaque brain is sensitive to the apoptogenic action of ketamine at both a fetal and neonatal age, and exposure duration of 5 h is sufficient to induce a significant neuroapoptosis response at either age. The pattern of neurodegeneration induced by ketamine in fetuses was different from that in neonates, and loss of neurons attributable to ketamine exposure was 2.2 times greater in the fetal than neonatal brains.
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Comparative Study
Impaired nociception and peripheral opioid antinociception in mice lacking both kinin B1 and B2 receptors.
Kinins (e.g., bradykinin) acting through the constitutively expressed B2 and the injury-induced B1 receptors are involved in pain and hyperalgesia, as previously shown by use of receptor-selective antagonists and single-receptor knockout models. Because the overall contribution of kinins to painful processes remains unclear, the aim of this study was to analyze pain-related behaviors of mice unable to respond to kinins because of a lack of both B1 and B2 receptors. ⋯ These data suggest that kinins are important for nociception associated with acute short-lasting inflammation but are less essential in chronic stages of pain. The results also highlight a new protective function of kinins via interactions with the opioid system.