The conformational and structural properties of the inhalational anesthetic isoflurane (1-chloro-2,2,2-trifluoroethyl difluoromethyl ether) have been probed in a supersonic jet expansion using Fourier-transform microwave (FT-MW) spectroscopy. Two conformers of the isolated molecule were identified from the rotational spectrum of the parent and several (37)Cl and (13)C isotopologues detected in natural abundance. The two most stable structures of isoflurane are characterized by an anti carbon skeleton (τ(C(1)-C(2)-O-C(3)) = 137.8(11)° or 167.4(19)°), differing in the trans (AT) or gauche (AG) orientation of the difluoromethyl group. The conformational abundances in the jet were estimated from relative intensity measurements as (AT)/(AG) ≈ 3:1. The structural preferences of the molecule have been rationalized with supporting ab initio calculations and natural-bond-orbital (NBO) analysis, which suggest that the molecule is stabilized by hyperconjugative effects. The NBO analysis of donor-acceptor (LP → σ*) interactions showed that these stereoelectronic effects decrease from the AT to AG conformations, so the conformational preferences can be accounted for in terms of the generalized anomeric effect.
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http://dx.doi.org/10.1039/c0cp02465a | DOI Listing |
Can J Vet Res
January 2025
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1.
The objective of this prospective study was to investigate whether repeated consecutive general anesthesia in horses undergoing 2 different anesthetic protocols could lead to improved recovery scores. Six healthy female Standardbred horses (453 ± 57 kg; 6.5 ± 4.
View Article and Find Full Text PDFIndian J Med Res
November 2024
Department of Receptor Biology and Tumor Metastasis, Chittaranjan National Cancer Institute, Kolkata, India.
Background & objectives The choice of anesthetic for better perioperative conservation of immune responses has always been contentious. This study investigated the differential impact of the intravenous anesthetic, propofol, and the volatile anesthetic, isoflurane on the T cell immune responses, if any, among individuals going through perioperative breast cancer. Methods Perioperative blood samples (preoperative, intraoperative and postoperative) collected from participants with breast cancer in two arms namely isoflurane arm (n=50) and the propofol arm (n=50) were analyzed for T cell immune response using flow cytometry and ELISA.
View Article and Find Full Text PDFFront Pharmacol
December 2024
Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.
Background: Mice play a crucial role in studying the mechanisms of general anesthesia. However, identifying reliable EEG markers for different depths of anesthesia induced by multifarious agents remains a significant challenge. Spindle activity, typically observed during NREM sleep, reflects synchronized thalamocortical activity and is characterized by a frequency range of 7-15 Hz and a duration of 0.
View Article and Find Full Text PDFVet Sci
November 2024
Department of Veterinary Medical Sciences, University of Bologna, 40126 Bologna, Italy.
The aim of this retrospective clinical study was to compare the combinations of ketamine/diazepam (KD group) and tiletamine/zolazepam (TZ group) for the induction of general anaesthesia in horses undergoing elective surgery. The data from the clinical and the anaesthetic records of 138 horses from 2021 to 2023 were evaluated, and the horses were divided in two groups: KD ( = 60) and TZ ( = 72). The horses were premedicated with romifidine and methadone IV; anaesthesia was induced with ketamine/diazepam for the KD group and tiletamine/zolazepam for the TZ group and was maintained with isoflurane and a constant rate infusion of romifidine.
View Article and Find Full Text PDFPsychedelic Med (New Rochelle)
December 2024
Departments of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Introduction: Psychedelic-induced experiences are thought to play an important role in the therapeutic actions of rapid-acting antidepressants. General anesthesia is one scenario in which patients can be rendered unconscious and masked to the psychedelic treatment, providing a simple yet effective method to examine drug-induced changes in the brain devoid of experiences.
Methods: Chronically stressed adult C57/BL6 male mice were given subhypnotic ketamine alone or ketamine and GABAergic anesthetic isoflurane at sedative (0.
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