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Current Opinion in Anaesthesiology Oct 2021To summarize the current data on neuroprotection derived by noble gas treatment focusing on xenon and argon. (Review)
Review
PURPOSE OF REVIEW
To summarize the current data on neuroprotection derived by noble gas treatment focusing on xenon and argon.
RECENT FINDINGS
Both xenon and argon have demonstrated neuroprotective properties in an array of disease models. However, current data for argon after traumatic brain injury (TBI) is conflicting. Recent human data is only available for xenon showing some beneficial aspects (fewer adverse events) but no effect on outcomes, such as incidence of postoperative delirium.
SUMMARY
Promising results are available for neuroprotection derived by noble gas treatment. Results for xenon are more consistent than those for argon. The mechanism of action of xenon (noncompetitive NMDA-receptor inhibition) is also better understood compared with that of argon. The evidence for argon's neuroprotective actions (particularly after TBI) remains uncertain.
Topics: Argon; Humans; Neuroprotection; Neuroprotective Agents; Noble Gases; Xenon
PubMed: 34224430
DOI: 10.1097/ACO.0000000000001033 -
Annual Review of Marine Science Jan 2019Natural mechanisms in the ocean, both physical and biological, concentrate carbon in the deep ocean, resulting in lower atmospheric carbon dioxide. The signals of these... (Review)
Review
Natural mechanisms in the ocean, both physical and biological, concentrate carbon in the deep ocean, resulting in lower atmospheric carbon dioxide. The signals of these carbon pumps overlap to create the observed carbon distribution in the ocean, making the individual impact of each pump difficult to disentangle. Noble gases have the potential to directly quantify the physical carbon solubility pump and to indirectly improve estimates of the biological organic carbon pump. Noble gases are biologically inert, can be precisely measured, and span a range of physical properties. We present dissolved neon, argon, and krypton data spanning the Atlantic, Southern, Pacific, and Arctic Oceans. Comparisons between deep-ocean observations and models of varying complexity enable the rates of processes that control the carbon solubility pump to be quantified and thus provide an important metric for ocean model skill. Noble gases also provide a powerful means of assessing air-sea gas exchange parameterizations.
Topics: Arctic Regions; Carbon Dioxide; Noble Gases; Oceans and Seas; Seawater
PubMed: 30216737
DOI: 10.1146/annurev-marine-121916-063604 -
British Journal of Pharmacology Apr 2015Several noble gases, although classified as inert substances, exert a tissue-protective effect in different experimental models when applied before organ ischaemia as an... (Review)
Review
Several noble gases, although classified as inert substances, exert a tissue-protective effect in different experimental models when applied before organ ischaemia as an early or late preconditioning stimulus, after ischaemia as a post-conditioning stimulus or when given in combination before, during and/or after ischaemia. A wide range of organs can be protected by these inert substances, in particular cardiac and neuronal tissue. In this review we summarize the data on noble gas-induced cardioprotection, focusing on the underlying protective mechanisms. We will also look at translatability of experimental data to the clinical situation.
Topics: Animals; Cardiotonic Agents; Helium; Humans; Ischemic Preconditioning, Myocardial; Xenon
PubMed: 25363501
DOI: 10.1111/bph.12994 -
Journal of Environmental Radioactivity Nov 2021Gaseous fission products have been produced via thermal neutron irradiation of a highly-enriched uranium target and extracted using a custom gas processing system for... (Review)
Review
Gaseous fission products have been produced via thermal neutron irradiation of a highly-enriched uranium target and extracted using a custom gas processing system for measurement on a prototype, high-resolution β - γ coincidence detection system. The gas was extracted and measured in two stages in order to measure the prompt and β-delayed fission products. This paper presents an overview of the system used to produce gaseous fission products, and the results of the advanced coincidence spectrometry techniques used to identify and quantify decays from the radionuclides produced, including the noble gases Kr, Kr, Kr, Xe, Xe, Xe and Xe, as well as I and Rb. The measurements were validated by determination of the nuclear decay half-lives, specifically for the ground state decay of Xe, which was found to be 9.15(49) hours and consistent with the literature value. This work demonstrates the UK capability to produce gaseous radionuclides for quality assurance and calibration purposes in Radionuclide Laboratories supporting the Comprehensive Nuclear-Test-Ban Treaty (CTBT).
Topics: Air Pollutants, Radioactive; Noble Gases; Radiation Monitoring; Radioisotopes; Xenon Radioisotopes
PubMed: 34492603
DOI: 10.1016/j.jenvrad.2021.106733 -
Current Drug Delivery 2018Surgical operations are impossible without administering proper analgesia. Advancement in the field of anesthesia has invariably resulted in the accomplishment of all... (Review)
Review
Surgical operations are impossible without administering proper analgesia. Advancement in the field of anesthesia has invariably resulted in the accomplishment of all surgical processes without any inconvenience. Admittedly, the use of noble gas is on the decline. The noble gases may not interact chemically with any other substance under normal temperature and pressure but they may interact with proteins and lipids. Different anesthetic molecules may stimulate either proteins or lipids in membrane. There is a connection between the anesthetic molecules and the hydrophobic region of the membrane. In the present review, we attempt to highlight the interaction between the anesthetic molecule with proteins and lipids and their effects. We sketched few noble gases and some other existing molecules such as halothane and alcohol which interacted with proteins and lipids.
Topics: Anesthetics; Animals; Humans; Lipids; Noble Gases; Proteins
PubMed: 30124152
DOI: 10.2174/1567201815666180820101255 -
British Journal of Anaesthesia Aug 2022The noble gases argon and xenon are potential novel neuroprotective treatments for acquired brain injuries. Xenon has already undergone early-stage clinical trials in... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The noble gases argon and xenon are potential novel neuroprotective treatments for acquired brain injuries. Xenon has already undergone early-stage clinical trials in the treatment of ischaemic brain injuries, with mixed results. Argon has yet to progress to clinical trials as a treatment for brain injury. Here, we aim to synthesise the results of preclinical studies evaluating argon and xenon as neuroprotective therapies for brain injuries.
METHODS
After a systematic review of the MEDLINE and Embase databases, we carried out a pairwise and stratified meta-analysis. Heterogeneity was examined by subgroup analysis, funnel plot asymmetry, and Egger's regression.
RESULTS
A total of 32 studies were identified, 14 for argon and 18 for xenon, involving measurements from 1384 animals, including murine, rat, and porcine models. Brain injury models included ischaemic brain injury after cardiac arrest (CA), neurological injury after cardiopulmonary bypass (CPB), traumatic brain injury (TBI), and ischaemic stroke. Both argon and xenon had significant (P<0.001), positive neuroprotective effect sizes. The overall effect size for argon (CA, TBI, stroke) was 18.1% (95% confidence interval [CI], 8.1-28.1%), and for xenon (CA, TBI, stroke) was 34.1% (95% CI, 24.7-43.6%). Including the CPB model, only present for xenon, the xenon effect size (CPB, CA, TBI, stroke) was 27.4% (95% CI, 11.5-43.3%). Xenon, both with and without the CPB model, was significantly (P<0.001) more protective than argon.
CONCLUSIONS
These findings provide evidence to support the use of xenon and argon as neuroprotective treatments for acquired brain injuries. Current evidence suggests that xenon is more efficacious than argon overall.
Topics: Animals; Argon; Brain Injuries; Brain Ischemia; Heart Arrest; Mice; Neuroprotection; Neuroprotective Agents; Noble Gases; Rats; Stroke; Swine; Xenon
PubMed: 35688658
DOI: 10.1016/j.bja.2022.04.016 -
Critical Care Medicine Sep 2016Noble gases have been attributed to organ protective effects in ischemia reperfusion injury in a variety of medical conditions, including cerebral and cardiac ischemia,... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Noble gases have been attributed to organ protective effects in ischemia reperfusion injury in a variety of medical conditions, including cerebral and cardiac ischemia, acute kidney injury, and transplantation. The aim of this study was to appraise the available evidence by systematically reviewing the literature and performing meta-analyses.
DATA SOURCES
PubMed, EMBASE, and the Cochrane Library.
STUDY SELECTION
Inclusion criteria specified any articles on noble gases and either ischemia reperfusion injury or transplantation. In vitro studies, publications without full text, review articles, and letters were excluded.
DATA EXTRACTION
Information on noble gas, organ, species, model, length of ischemia, conditioning and noble gas dose, duration of administration of the gas, endpoints, and effects was extracted from 79 eligible articles. Study quality was evaluated using the Jadad scale. Effect sizes were extracted from the articles or retrieved from the authors to allow meta-analyses using the random-effects approach.
DATA SYNTHESIS
Argon has been investigated in cerebral, myocardial, and renal ischemia reperfusion injury; helium and xenon have additionally been tested in hepatic ischemia reperfusion injury, whereas neon was only explored in myocardial ischemia reperfusion injury. The majority of studies show a protective effect of these noble gases on ischemia reperfusion injury across a broad range of experimental conditions, organs, and species. Overall study quality was low. Meta-analysis for argon was only possible in cerebral ischemia reperfusion injury and did not show neuroprotective effects. Helium proved neuroprotective in rodents and cardioprotective in rabbits, and there were too few data on renal ischemia reperfusion injury. Xenon had the most consistent effects, being neuroprotective in rodents, cardioprotective in rodents and pigs, and renoprotective in rodents.
CONCLUSIONS
Helium and xenon show organ protective effects mostly in small animal ischemia reperfusion injury models. Additional information on timing, dosing, and comparative efficacy of the different noble gases, as well as confirmation in large animal models, is needed before designing clinical trials.
Topics: Animals; Humans; Noble Gases; Reperfusion Injury
PubMed: 27071065
DOI: 10.1097/CCM.0000000000001717 -
Reports on Progress in Physics.... Nov 2014Hyperpolarized noble gases (HNGs), polarized to approximately 50% or higher, have led to major advances in magnetic resonance (MR) imaging of porous structures and... (Review)
Review
Hyperpolarized noble gases (HNGs), polarized to approximately 50% or higher, have led to major advances in magnetic resonance (MR) imaging of porous structures and air-filled cavities in human subjects, particularly the lung. By boosting the available signal to a level about 100 000 times higher than that at thermal equilibrium, air spaces that would otherwise appear as signal voids in an MR image can be revealed for structural and functional assessments. This review discusses how HNG MR imaging differs from conventional proton MR imaging, how MR pulse sequence design is affected and how the properties of gas imaging can be exploited to obtain hitherto inaccessible information in humans and animals. Current and possible future imaging techniques, and their application in the assessment of normal lung function as well as certain lung diseases, are described.
Topics: Animals; Humans; Lung; Magnetic Resonance Imaging; Noble Gases; Spectrum Analysis
PubMed: 25360484
DOI: 10.1088/0034-4885/77/11/116701 -
Pharmacology & Therapeutics Apr 2016The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological... (Review)
Review
The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological properties. Despite a relative paucity of knowledge of their mechanisms of action, some of the noble gases have been used successfully in the clinic. Studies with xenon have suggested that the noble gases as a class may exhibit valuable biological properties such as anaesthesia; amelioration of ischemic damage; tissue protection prior to transplantation; analgesic properties; and a potentially wide range of other clinically useful effects. Xenon has been shown to be safe in humans, and has useful pharmacokinetic properties such as rapid onset, fast wash out etc. The main limitations in wider use are that: many of the fundamental biochemical studies are still lacking; the lighter noble gases are likely to manifest their properties only under hyperbaric conditions, impractical in surgery; and administration of xenon using convectional gaseous anaesthesia equipment is inefficient, making its use very expensive. There is nonetheless a significant body of published literature on the biochemical, pharmacological, and clinical properties of noble gases but no comprehensive reviews exist that summarize their properties and the existing knowledge of their models of action at the molecular (atomic) level. This review provides such an up-to-date summary of the extensive, useful biological properties of noble gases as drugs and prospects for wider application of these atoms.
Topics: Animals; Humans; Noble Gases; Xenon
PubMed: 26896563
DOI: 10.1016/j.pharmthera.2016.02.002 -
European Radiology 1998The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications.... (Review)
Review
The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications. Non-radioactive noble gases with a nuclear spin 1/2 (He-3, Xe-129) can be hyperpolarized by optical pumping. Polarization is transferred from circularly polarized laser light to the noble-gas atoms via alkali-metal vapors (spin exchange) or metastable atoms (metastability exchange). Hyperpolarization results in a non-equilibrium polarization five orders of magnitude higher than the Boltzmann equilibrium compensating for the several 1000 times lower density of noble gases as compared with liquid state hydrogen concentrations in tissue and allows for short imaging times. Hyperpolarization can be stored sufficiently long (3 h to 6 days) to allow for transport and application. Magnetic resonance systems require a broadband radio-frequency system - which is generally available for MR spectroscopy - and dedicated coils. The hyperpolarized gases are administered as inhalative "contrast agents" allowing for imaging of the airways and airspaces. Besides the known anesthetic effect of xenon, no adverse effects are observed in volunteers or patients. Pulse sequences are optimized to effectively use the non-renewable hyperpolarization before it decays or is destroyed, using fast low-flip-angles strategies to allow for dynamic/breath-hold imaging of highly diffusible (He) or soluble (Xe) gases with in vivo T1-times well below 1 min. Since helium is not absorbed in considerable amounts, its application is restricted to the lung. Xe-129 is also under investigation for imaging of white matter disease and functional studies of cerebral perfusion. Magnetic resonance imaging using hyperpolarized gases is emerging as a technical challenge and opportunity for the MR community. Preliminary experience suggests potential for functional imaging of pulmonary ventilation and cerebral perfusion.
Topics: Adult; Animals; Brain; Brain Diseases; Female; Guinea Pigs; Helium; Humans; Image Enhancement; Image Processing, Computer-Assisted; Isotopes; Lung; Lung Diseases; Magnetic Resonance Imaging; Mice; Noble Gases; Xenon Isotopes
PubMed: 9601972
DOI: 10.1007/s003300050479